- Email: [email protected]
Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char
Journal of the Energy Institute xxx (2017) 1e14
Contents lists available at ScienceDirect
Journal of the Energy Institute journal homepage: http://www.journals.elsevier.com/journal-of-the-energyinstitute
Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char Neelanjan Bhattacharjee, Asit Baran Biswas* Department of Chemical Engineering, University of Calcutta, UCSTA, 92 A. P. C. Road, Kolkata 700 009, West Bengal, India
a r t i c l e i n f o
a b s t r a c t
Article history: Received 21 October 2016 Received in revised form 22 February 2017 Accepted 27 February 2017 Available online xxx
In the present work, fast pyrolysis of Alternanthera philoxeroides was evaluated with a focus to study the chemical and physical characteristics of bio-oil produced and to determine its practicability as a transportation fuel. Pyrolysis of A. philoxeroides was conducted inside a semi batch quartz glass reactor to determine the effect of different operating conditions on the pyrolysis product yield. The thermal pyrolysis of A. philoxeroides were performed at a temperature range from 350 to 550 C at a constant heating rate of 25 C/min & under nitrogen atmosphere at a flow rate of 0.1 L/min, which yielded a total 40.10 wt.% of bio-oil at 450 C. Later, some more sets of experiments were also performed to see the effect on pyrolysis product yield with change in operating conditions like varying heating rates (50 C/min, 75 C/min & 100 C/min) and different flow rates of nitrogen (0.2, 0.3, 0.4 & 0.5 L/min). The yield of biooil during different heating rate (25, 50, 75 and 100 C/min) was found to be more (43.15 wt.%) at a constant heating rate of 50 C/min with 0.2 L/min N2 gas flow rate and at a fixed pyrolysis temperature of 450 C. The High Heating Value (HHV) value of bio-oil (8.88 MJ/kg) was very less due to presence of oxygen in the biomass. However, the high heating value of bio-char (20.41 MJ/kg) was more, and has the potential to be used as a solid fuel. The thermal degradation of A. philoxeroides was studied in TGA under inert atmosphere. The characterization of bio-oil was done by elemental analyser (CHNS/O analyser), FTIR, & GC/MS. The char was characterized by elemental analyser (CHNS/O analysis), SEM, BET and FT-IR techniques. The chemical characterization showed that the bio-oil could be used as a transportation fuel if upgraded or blended with other fuels. The bio-oil can also be used as feedstock for different chemicals. The bio-char obtained from A. philoxeroides can be used for adsorption purposes because of its high surface area. © 2017 Energy Institute. Published by Elsevier Ltd. All rights reserved.
Keywords: A. philoxeroides biomass Pyrolysis Bio-oil Bio-char
1. Introduction Our present world relies on energy, obtained from different sources of fossil fuels. Due to vast expanding urbanization in cities throughout the world, reliability on fossils fuels has also plummeted. Hunger for energy needs is depleting fossil fuel sources day by day. With increase in energy demands, rise in petroleum prices and environmental related problems alternative way needs to be implemented. This crisis can only be overcome by the use of biomass, which is the third largest energy source present in today's world. For the production of conventional hydrocarbon transportation fuels, the only renewable source of fixed carbon is biomass [1]. Biomass generally consists of cellulose, hemicellulose, & lignin, which are good source of fuels and chemicals. Biomass can be converted into transportation fuels by two major processes viz. (a) thermo-chemical (combustion, gasification, pyrolysis, liquefaction, hydrogenation, carbonization and torrefaction) and (b) biochemical (anaerobic and aerobic fermentation to produce ethanol, butanol, methanol, etc.). Different structures of biomass decomposed at various temperature ranges. Lignin decomposes at higher temperature range compare to cellulose and hemicellulose, which decomposes at lower temperature range. Hence, lignin gains thermal stability during thermal degradation [2]. Out of these processes
* Corresponding author. E-mail address: [email protected] (A.B. Biswas). http://dx.doi.org/10.1016/j.joei.2017.02.011 1743-9671/© 2017 Energy Institute. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
2
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
pyrolysis is more efficient to convert biomass into three different states of matter (solid: char, liquid: bio-oil, gas: Syn-gas). The bio-oil obtained from different biomass via thermo-chemical conversion, consists more than 300 organic compounds. Bio-oil thus obtained from thermo-chemical conversion is a good source of feedstock for different chemical manufacturing, and also has higher energy content compare to biomass, and can be transported easily. Another advantage of bio-oil is that it is cleaner than biomass, since many impurities (minerals and metals) are left in the bio-char after pyrolysis [3]. The bio-oil can be upgraded to refined fuels, which can be use directly or blended with different petroleum products or use as chemical feedstock [4]. Due to their high viscosity, poor heating value, corrosiveness and instability, their direct use as conventional fuels may present some difficulties [5,6]. The bio-char can also be used as solid fuel or used for other applications such as soil modification, manufacturing of activated carbon and bio-carbon electrodes or used in metallurgical and leisure industries [7e9]. The Syn-gas which is composed of methane, carbon dioxide, hydrogen, carbon monoxide, trace amount of propane and other compounds, can be used to fire boilers for electricity generation or can be used as an alternative to Liquid petroleum gas. Invasive aquatic weeds possess problem to native flora and fauna. They have capability to absorb all nutrients from wetlands within two weeks and destroy all native plants, causing huge problems [10]. They pose problems by blocking waterways, jamming turbines in hydel power plants, reducing native fish population, inflecting water, providing shelter to disease causing insects, etc. Therefore, they should be destroyed or converted into organic manure and transportation fuels. There have been many studies on the pyrolysis of different weeds to produce bio-oil and other products. Kittiphop Promdee et al. [11], carried pyrolysis experiments of Manila Grass and water hyacinth in tube furnace reactor in N2 atmosphere in temperature range of 450e600 C to study the effect of feeding rate, the control gas flow, the temperatures in reactor and reactor operate on pyrolysis product yields. Nazim Muradov et al., carried the pyrolysis of fast-growing aquatic biomass e Lemna minor (commonly known as duckweed) in a quartz tube reactor purged with argon gas (36e150 ml/min) at temperature range from 400 to 700 C with the emphasis on the characterization of main products of pyrolysis. During the experiment, it was observed that even at relatively low rates of pyrolysis (at 500 C) it is possible to obtain in excess of 40 wt.% of bio-oil from dry duckweed. Faster pyrolysis rates would significantly increase the bio-oil yield [12]. Seung-Soo Kim et al.; carried the pyrolysis of Milkweed in a thermo-gravimetric analyser and a bubbling fluidized bed reactor in nitrogen atmosphere at a gas flow rate of 40 ml/min, in a pyrolysis temperature maintained between 425 C and 550 C to see the effect of temperature on pyrolysis yield. From the experiment Seung Kim et al. concluded that unlike other lignocellulosic biomass, milkweed has a higher HHV (>30 MJ/kg) and higher density and pH compared to other biomass, and can be easily converted to hydrocarbon fuel [13]. P. Manara et al. carried the pyrolysis of red seaweed residues by means of a thermo-gravimetric analyser and a fast pyrolysis captive sample reactor at a range of 450e650 C in helium atmosphere. P. Manara found that product yield distribution is a function of the feedstock and the temperature & at medium temperature (550 C), pyrolysis gives higher oil (reaching values of 70 wt.%) yields and lower char yields. Alternanthera philoxeroides, (Martius) Grisebach, a South American weed of the family amaranthaceae has also been discovered in Madhya Pradesh, Maharashtra, Assam, Meghalaya, Arunachal Pradesh, Bihar, Haryana, Himachal Pradesh, Karnataka, Kerala, Orissa, Tamil Nadu, Uttarakhand, Uttar Pradesh and West Bengal. Like several other American weeds, these invasive weeds might have reached India along with some packing material during the Second World War. The species was collected for the first time in India near an aerodrome at Calcutta [14]. Alligator weeds have a negative impact on waterways; it reduces oxygen content, light penetration in water also reduces water flow. It also has a negative impact on zoological and botanical habitat such as fish and birds, death of other water plants. It is rather difficult to control and helps in the breeding of mosquitoes. In this study, A. philoxeroides was selected as feedstock for bio-fuel production and objectives of the study are as follows: 1. Determine the effect of pyrolysis temperature, sweeping gas flow rates, & heating rates on product yield. 2. Characterization of the liquid product obtained at ideal pyrolysis condition and to investigate whether it can be used as an alternative of fossil fuels or as feedstocks for different chemical manufacturing. 3. Characterization of the bio-char obtained as a result of pyrolysis and find its applicability as a solid fuel.
2. Experimental setup and procedure 2.1. Raw material preparation The biomass sample (feedstock) used in the study was obtained from Howrah district, West Bengal, India. Prior to use, the biomass was thoroughly washed to remove any foreign materials that came with the plant. The cleaned sample was then sun dried for 7 long days and later dried in a hot air oven at 100 ± 5 C for 4 h to remove all unbound moisture. The dried sample was then grinded and passed through a screen of 72 B.S. The screened samples were used for the fast pyrolysis process. 2.2. Pyrolysis system The pyrolysis was carried out in the experimental setup given in Fig. 1. The glass reactor was 12.7 cm in height and has 3 cm of internal diameter. The glass reactor was connected to a fractionating column, having dimension of 30 cm in height and internal diameter of 3 cm. The fractionating column was insulated up to condenser opening to avoid heat loss and pre-condensation. The reactor was heated externally by 800 Watts electric muffle furnace. Temperature within the reactor was measured by a k-type thermocouple attached to an external PID controller. Another PID controller controlled the heating rate and temperature of furnace. The outlet of the reactor was connected to a series of condensers to condense the vapours coming out of the reactor. The condensate was collected in measuring cylinder after the experiment. The yields of the liquid product and chars were determined by weighing. The Syn-gas volume was measured by downwards displacement of water. The compositional analysis of Syn-gas by GCeMS gave out the exact mol %, of the different gases present. Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
3
Fig. 1. Schematic diagram of pyrolysis experimental setup. 1) Nitrogen cylinder; 2) Rotameter; 3) K-type thermocouple connected to PID controller; 4) Insulated fractionation Column; 5) Muffle Furnace; 6) Pyrex Glass Reactor; 7) PID controller; 8) Ice cooled 30 L water tank; 9) Submersible Pump; 10) Liebig Condenser; 11) Separating funnel; 12) Condenser; 13) Condensers; 14) Gas vent.
Liquid yieldð%Þ ¼
Char yield % ¼
gas yield % ¼
wt of liquid; grams 100 wt of dry biomass; grams
char weight 100 feed weight
Sum of the masses of every component of Syn gas 100 wt of dry biomass; grams
Loss % ¼ 100 ðLiquid yield þ char þ GasÞ
(1)
(2)
(3) (4)
The liquid yield consists to two different phases, the top layer is the bio-oil and bottom one is the aqueous layer. The bio-oil was separated from the aqueous phase with the help of separating funnel. The separated bio-oil was later bottled and kept for further analysis. Syn-gas produced during different temperatures of pyrolysis was measured by water displacement method and was collected overtime for compositional analysis. The pyrolysis experiments were performed thrice for better results. One-way analysis of variance (ANOVA) was conducted in origin 8 using the data obtained from the pyrolysis of A. philoxeroides. To check whether the values (pyrolysis yield) obtain because of difference in temperature, variation in N2 gas flow rate and effect of different heating rate are statically significant, the probability P value needs to be determined. If P values are small, then it is doubtful that the differences in the values of dependent variables observed are coincidental and due to random sampling [12]. 2.3. Characterization 2.3.1. Proximate analysis The proximate analysis of the dry biomass sample (feedstock) was determined by IS: 1350-1(1984) method for the evaluation of moisture, ash, volatile and fixed carbon content. Proximate analysis is an easiest way to determine the fuel quality of a solid material. High moisture & ash content will have a negative effect on heating rate of biomass and lower combustion efficiency, high volatile content of a solid fuel is not appreciable because it will require higher oxygen during combustion [15]. 2.3.2. Ultimate analysis The ultimate analysis or elemental analysis of the dry biomass sample was determined by using ZEISS EVO 18 (Germany) and Perkin Elmer 2400 II CHNS/O; analyser for the evaluation of carbon, hydrogen, nitrogen, oxygen, phosphorous, and other elements. Ultimate analysis helps in evaluating theoretical air required for complete combustion, volume of fuel gas generated per kg of fuel fired, water vapour & sulphur content of flue gas. Carbon and hydrogen content of fuel help in the determination of calorific value, when the sum of these components is subtracted from 100, it gives oxygen percentage [16]. Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
4
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
2.3.3. Compositional analysis The compositional analysis (hemicelluloses, cellulose and lignin) of the dry biomass sample was determined by following the method prescribed by Haiping Yang et al. [17]. 2.3.3.1. Extractive analysis. The dry biomass sample of A. philoxeroides (X1) was leached with a mixture of ethyl alcohol/benzene in 1:2 volumes at room temperature for 3 h. Later a Whatman filter paper 41 was used to separate the biomass ethyl alcohol/benzene mixture. The leached biomass was then dried in a hot air oven maintained at 85 ± 5 C, for constant weight. The residue was then cooled in a desiccator and weighted again (X2). The extractive weight percentage was the calculated using the below formula:
Extractive analysisðWÞ ¼
ðX1 X2Þ 100 X1
(5)
2.3.3.2. Lignin analysis. Nearly 1 g of sample (X3) from the leached residue was transferred into a conical flask of 500 ml. Prepare a 200 ml solution of H2SO4 (98%) of 1 N and pour this solution into the conical flask. Seal the conical flask mouth with non-absorbing cotton and keep the mixture at 8e15 C for 24 h. After 24 h, add about 200 ml of double distil water into the mixture and place it inside an autoclave for 20 min (15 psi). Place a perforated porcelain funnel of 90 mm over a conical flask (500 ml) with side outlet, connected to a vacuum source for filtration. Place a weighted Whatman 41 filter paper (90 mm) over the perforated porcelain funnel and pour the mixture over it, little by little. Add double distil water in small volumes until the treated biomass becomes neutral (pH). Carefully place the Whatman 41 filter paper over a petri dish (Dia: 100 mm) and heat it inside a hot air oven maintained at 100 ± 5 C. Place the dried sample inside desiccator until constant weight is obtained (X4). The lignin weight percentage was calculated using the below formula:
Lignin Analysis ¼
ðX3 X4Þ 100 X3
(6)
2.3.3.3. Hemicellulose content. About 1 g of sample (X5) from the leached residue was transferred into a conical flask of 500 ml. Prepare a 150 ml solution of NaOH of 1 N and pour this solution into the conical flask. Seal the conical flask with non-adsorbing cotton and boil it inside an autoclave for 20 min maintained at 15 psi. Place a perforated porcelain funnel of 90 mm over a conical flask (500 ml) with side outlet, connected to a vacuum source. The residue was filtered with distilled water. This process was continued until water remained neutral, which means have to be removed ions and salts, and air-drying. Later the residue was dried in a hot oven at 100 ± 5 C for constant weight. The residue was cooled inside a desiccator and then weighted (X6). The hemicellulose wt.% is calculated by using below formula.
Hemicellulose Content ¼
ðX5 X6Þ 100 X5
(7)
2.3.3.4. Cellulose content. The cellulose weight % was calculated using the below formula:
Cellulose content ¼ 100 ðExtractive content þ Lignin content þ hemicellulose contentÞ
(8)
2.3.4. High heating value (HHV) To determine the high heating value of biomass, bio-oil & bio-char, a model used in Friedl et al. [18] was considered. The data obtained from CHNS/O analysis were put in that model, to determine the high heating value of the substances. High Heating value (MJ/kg): (3.55C2 232C 2230 H þ 51.2 C H þ 131N þ 20600)/(1000) [18].
2.3.5. pH determination Bio-char pH was determined by mixing 1 g of bio-char in 50 ml of deionised water and was sonicated for 1 h. The supernatant was tested for determining pH by a digital pH meter. 2.3.6. Thermal analysis Thermo-gravimetric analysis of the dry biomass sample was determined by using TA instrument SDT-Q600 Simultaneous TGA/DSC, V8.2 Build 100. About 5 mg of dry biomass sample was placed over an Al2O3 crucible and was heated up-to a final temperature of 600 C at 25 C/ min under inert (N2) atmosphere. In order to avoid undesirable oxidation during the thermal decomposition of dry biomass sample, a constant flow rate 0.1 L/min of N2 was maintained inside the apparatus. 2.3.7. Water content of bio-oil The water content helps in determining the quality of bio-oil, which can affect the heating values, pH, viscosity and the storage characteristics. The water content of the bio-oil was determined by dean stark apparatus using toluene as solvent. About 10 ml of bio-oil was mixed with 80 ml of toluene and placed in a 250 ml flask connected to a dean stark apparatus. Azeotropic distillation separates the water from toluene. Water left in flask was cooled before weighing [19].
Water content % ¼
Weight of water 100 weight of bio oil
(9)
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
5
2.3.8. Total acid number Presence of acid and other impurities in bio-oil can be corrosive for storage materials. The total acid number of bio-oil was determined by following ASTM D664. KOH is used as a base to neutralise the acid present in 1 g of bio-oil. About 0.3 g of bio-oil was mixed with 5 ml of diethyl ether and titrated against 0.1 M KOH solution using phenolphthalein as indicator. The acid value is determined as follows [20]:
ml of 0 : 1M KOH consumed by sample Molarity of KOH 56:1 Weight in grams of the sample
(10)
2.3.9. FT-IR The functional groups characterization of bio-oil and bio-char was conducted in a Thermo-Fisher Scientific Nicolet i35 (iD3 ATR) (FT-IR) at 4 cm1 resolution in the range of 4000e600 cm1. 2.3.10. GCeMS analysis The GCeMS analysis of the bio-oil samples was carried out using a Clarus 500 GC instrument (PerkineElmer) equipped with a TCD and was coupled to a Clarus 500 MS system (PerkineElmer). The bio-oil was dissolved in HPLC grade dichloromethane and filtered before gas chromatography and mass spectroscopy analysis. About 1 ml of sample was injected though the injecting vent for 30 s. The injecting temperature was 270 C and helium was used as a carrier gas at a flow rate of 2 ml/min. The oven temperature was maintained at 40 C during the first 4 min, later heated at a rate of 5 C/min to a final temperature of 280 C with a total run time of 45 min. A polar capillary column (BP-5) of internal diameter 0.25 mm and length 30 m was used for the analysis of chemical compounds present in the bio-oil. The compounds present in bio-oil were ionised at 70 eV in an electron impact ionization device (MS). The ion source temperature and interface temperature was maintained at 210 C & 225 C. The chromatogram data obtained after analysis were determined through National institute of science and technology (NIST) library. The Syn-gas samples collected at different pyrolysis temperature were analysed on an Agilent 6890N GC equipped with HID (H2) and TCD (CO2, CO, CH4, C2H6, & C3H8). Oven was programmed to hold at 55 C for 7 min, ramp at 20 C/ min up-to 250 C and again hold for 15 min. The detectors were maintained at 150 C and for quantification, mixture of different gases were also used. 2.3.11. SEM analysis The surface morphology of bio-char was determined using ZEISS EVO 18 SEM analyser at a magnification of 5KX with an acceleration voltage of 15 KV. The sample was pasted over a carbon tape and later coated with nano gold dust and analysed under hydrogen atmosphere. 2.3.12. BET analysis The surface area of biomass and bio char was determined using Quantacrome instruments NOVA 1000 BET surface area and pore size analyser in nitrogen atmosphere. The sample was degassed in vacuum chamber at 50 & 180 C for 5 h under nitrogen atmosphere. The degassed sample was then analysed in a Dewar containing liquid nitrogen. 3. Results and discussions 3.1. Compositional analysis of A. philoxeroides biomass powder The proximate analysis and ultimate analysis of the A. philoxeroides biomass powder is outlined in Table 1. From Table 1, it is evident that the A. philoxeroides biomass powder has lower moisture content and higher volatile matter content which will pleasant for bio-oil
Table 1 Proximate and ultimate analysis of biomass. Biomass (wt.%) Properties (proximate) Moisture content Volatile matter content Fixed carbon content Ash content Extractive content Hemicellulose content Lignin content Cellulose Properties (Ultimate) Carbon Hydrogen Nitrogen Oxygen Phosphorous (EDX analysis) HHV (MJ/kg) H/C O/C N/C P/C Empirical formula
4.16 53.87 23.81 18.16 14.71 32.13 24.15 29.01 35.26 5.79 3.65 54.94 0.36 14.85 MJ/kg 1.97 1.17 0.09 0.0082 CH1.97 N0.09 O1.17 P0.0082
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
6
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
production [21], but due to its higher ash content it will have a negative effect on bio-oil yield and will also yield more bio-char and Syn-gas [22]. Higher ash content in biomass will lead to less release of volatile matter during heating, resulting into higher bio-char content and lowering heating value of the feedstock. The biomass sample has a higher volatile matter content which can result in less loss of fixed carbon during pyrolysis [23]. HHV depends upon carbon, oxygen and ash content in the feedstock. Higher percentage of carbon content with lower percentage of oxygen and ash contents results in higher HHV of the feedstock. The HHV of the feedstock was 14.85 MJ/kg [18], which is due to higher O/C and ash content in the feedstock. 3.2. Thermal analysis of biomass The thermal stability and volatile component fraction can be determined by thermo-gravimetric analysis by monitoring the change in weight during the heating of the specimen. The analysis is mainly carried out in the presence of air, nitrogen or inert gases such as helium and argon. Thermo-gravimetric analysis of alligator weed was conducted in presence of N2 at a heating rate of 25 C/min in Fig. 2. The first region of thermal degradation of biomass occurred in between 115 C, which resulted in a weight loss of 4.93%, due to presence of moisture and few volatile. The second region of thermal degradation occurred at a temperature range of 115 Ce356 C, which resulted a total weight loss of 63.38% due to decomposition of cellulose, hemi-cellulose and formation of volatiles (carbon dioxide and carbon mono-oxide) and loss of oxygenated, nitrogen, and other elemental compounds. The third stage of thermal degradation occurred in the temperature range of 356 Ce600 C, with a loss in weight of 31.69% due to degradation of lignin as well as original structure also gets destroyed. After this temperature, no further decomposition takes place. From DTG curve, it is evident that dehydration happens below 120 C, de-volatilisation takes place from 120 to 380 C & decomposition happens from 380 to 600 C. The result of TGA and DTG curve shows that 350e550 C temperature range would be optimal for pyrolysis zone. The yield of char at different pyrolysis temperature is quite similar to the results obtain from TGA, which is shown in Table 2. The higher char yield was due to the presence of higher inorganic material, which can be characterised as ash. 3.3. Influence of temperature on pyrolysis product yields To verify the effect of temperature on the yield of pyrolysis product, several experiments were conducted at various temperature intervals, ranging from 350, 375, 400, 425, 450, 475, 500, 525 & 550 C at a constant heating rate of 25 C/min with a sweeping N2 gas flow rate of 0.1 L/min. From Table 3 and Fig. 3, it can be concluded that, with the rise in temperature from 350 C to 450 C, the yield of oil (32.13e40.1 wt.%) and yield of gas increased (12.71e23.14 wt.%) while decrease in bio-char yield (50.56e34.21 wt.%). The decrease in char percentage was due to the secondary decomposition and loss of volatile matter at higher pyrolysis temperature [24,25]. Increase in temperature caused higher gas yield and lower oil yield, which was due to the secondary cracking of pyrolysis vapour at higher pyrolysis temperature [26]. Since the pyrolysis process is fast, the vapour residence time (Table 3), decreased with increase in temperature. Since, shorter vapour residence time in heated zone yielded high bio-oil percentage over char. The loss percentage was >10% up-to 450 C and further rise in temperature from 450 C to 550 C caused higher loss percentage. From the above analysis, it can be concluded that the optimum temperature for oil production is 450 C in case of A. philoxeroides in the present experimental conditions. After subjecting the experimental data in one-way ANOVA (origin 8), the obtained P is significant at 0.05 level using Tukey model. The p values indicate that the variation in yield (liquid, char, & gas) due to change in temperature from 350 C to 550 C are statistically significant. The composition of Syn-gas obtained as a result of pyrolysis with fixed N2 gas flow rate & heating rate (25 C/min) is also illustrated in Table 3. The major gaseous product of A. philoxeroides pyrolysis are H2, CO2, CO, CH4, C2H6 and C3H8. Out of these six major gases, percentage of CO2 was more, which later decreased with rise in pyrolysis temperature. The concentration of CH4 increased with rise in temperature. The percentage of H2 also increased at elevated temperature of pyrolysis due to severe cracking of all the condensable and non-condensable products. The reaction between CO2 and carbon in char also lead to the increase of CO percentage at higher pyrolysis temperature, due to reverse Boudouard reaction [27e29]. Reverse Boudouard reaction is mainly responsible for CO2 depletion.
Fig. 2. TGA and DTG of Alternanthera philoxeroides biomass powder.
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
7
Table 2 Comparison of char obtained from TGA and pyrolysis. Temperature C
TGA (wt.%)
Pyrolysis Char (wt.%)
350 375 400 425 450 475 500 525
54.103 40.94 37.58 35.26 33.19 30.59 27.75 25.16
50.56 45.05 39.67 36.01 34.21 31.27 28.61 26.57
Table 3 Influence of different pyrolysis temperature on product yields at constant heating rate of 25 C/min & 0.1 L/min (N2 gas) flow rate. Characteristics
Temperature C
350
375
400
425
450
475
500
525
550
Muffle furnace Yield wt.%
Time taken to reach@ 25 C/min (Heating rate) Total Liquid Organics Water Char Gas Loss Closure (%) Reaction time N2 gas Syn-gas Time (s) Gas selectivity H2 CO2 CO CH4 C2H6 C3H8 g/mol
14 32.13 10.72 21.40 50.56 12.71 4.60 95.4 48 0.1 0.048 2.03 mol% 4.352 71.28 18.04 4.53 0.68 1.37 121.6
15 33.96 13.73 20.43 45.05 13.74 7.25 92.75 46 0.1 0.057 1.94 mol% 4.596 69.93 18.59 4.67 0.78 1.48 80.43
16 35.32 15.91 19.41 39.67 15.77 9.24 90.76 44 0.1 0.064 1.48 mol% 4.74 68.17 18.48 4.88 0.84 2.59 68.39
17 38.14 18.27 19.27 36.01 16.38 9.47 90.53 41 0.1 0.071 1.33 mol% 4.78 69.25 18.63 4.49 0.56 2.29 55.57
18 40.10 19.99 20.11 34.21 16.48 9.21 90.79 37 0.1 0.08 1.06 mol% 5.03 67.16 19.45 4.93 0.65 2.78 43.77
19 38.77 18.56 20.21 31.27 17.98 11.98 88.02 33 0.1 0.093 0.91 mol% 5.09 68.13 19.51 5.04 0.88 1.35 32.37
20 36.42 17.16 19.26 28.61 19.81 15.16 84.84 29 0.1 0.13 0.85 mol% 8.44 61.27 20.52 6.63 0.93 2.21 20.82
21 34.74 14.71 20.03 26.57 21.58 17.11 82.59 24 0.1 0.178 0.79 mol% 9.73 57.39 22.19 6.78 0.97 2.94 8.84
22 31.93 13.80 18.13 23.70 23.14 21.23 78.77 19 0.1 0.251 0.72 mol% 15.04 55.45 19.77 6.93 0.68 2.13 4.45
Time (min) Flow rate L/min Flow rate L/min Vapour residence time Sys-gas composition analysis
Molecular weight
3.4. Influence of sweeping gas flow rate on pyrolysis product yields Nitrogen flow has an impact on the residence time of vapour phase and restrains the secondary cracking reactions at vapour phase [30]. To determine the influence of the sweeping gas flow rate, experiments was carried out under varying nitrogen flow rates of 0.1, 0.2, 0.3, 0.4, & 0.5 L/min at a fixed pyrolysis temperature of 450 C, with a constant heating rate of 25 C/min. The effect of sweeping gas flow on pyrolysis product yield is represented in Table 4 and Fig. 4. The maximum oil yield was 42.28% with a sweeping gas flow rate of 0.2 L/min. Short vapour residence time (0.98 s) of pyrolysis vapours in the reactor was due to the high flow rates of sweeping N2 gas. The maximum yield of bio-oil can only be accomplished with short vapour
Fig. 3. Influence of different pyrolysis temperature on product yields at constant heating rate of 25 C/min & 0.1 L/min (N2) flow rate.
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
8
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
Table 4 Influence of sweeping gas flow rate on pyrolysis product yields at fixed pyrolysis temperature @ 450 C. Characteristics
Temperature C
450
450
450
450
450
Muffle furnace Yield wt.%
Time taken to reach 450 C @ 25 C/min (Heating rate) Total Liquid Organics Water Char Gas Loss Closure (%) Reaction time N2 gas Syn-gas Time (s) Gas selectivity H2 CO2 CO CH4 C2H6 C3H8 g/mol
18 40.10 19.99 20.11 34.21 16.48 9.21 90.79 37 0.1 0.08 1.06 mol% 5.03 67.16 19.45 4.93 0.65 2.78 43.77
18 42.28 23.17 19.11 30.33 20.54 6.85 93.15 35 0.2 0.106 0.98 mol% 5.28 66.89 19.83 5.16 0.78 2.06 99.72
18 38.48 19.27 19.21 28.37 21.46 11.29 88.31 31 0.3 0.125 0.95 mol% 5.13 66.38 19.88 5.23 0.81 2.57 161.35
18 36.25 16.22 20.03 27.01 23.77 12.97 87.03 29 0.4 0.148 0.93 mol% 5.13 66.36 19.92 5.19 0.88 2.52 204.52
18 33.96 15.17 18.78 26.23 23.89 15.92 84.07 26 0.5 0.166 0.89 mol% 5.17 66.28 19.80 5.21 0.93 2.61 254.15
Time (min) Flow rate L/min Flow rate L/min Vapour residence time Sys-gas composition analysis
Molecular weight
Fig. 4. Influence of sweeping gas flow rate on pyrolysis product yields at fixed pyrolysis temperature @ 450 C.
residence time of pyrolysis vapours and lower char yield. From Table 4, it was evident the vapour residence time reduced with increase in the flow rate of N2 gas. The yield of pyrolysed oil at 0.2 L/min was more compared to 0.3, 0.4 and 0.5 L/min. Moreover, increasing inert gas flow rate from 0.1 to 0.5 L/min caused higher percentage of volatile matter production. Since, fast flow rate stops the ideal quenching of thermally cracked pyrolysis vapours. As a result, chemical reactions stops before the valuable initial reaction products can be degraded [31,32]. It can be concluded from the experiment that 0.2 L/min is the best sweeping gas flow for pyrolysed oil production at 450 C. After subjecting the experimental data in one-way ANOVA (origin 8), it showed Sig 1 (significance ¼ 1), which indicated that the means difference is significant at the 0.05 level. The p (<0.005) values indicate that the variation in yield (liquid, char, & gas) due to variation in N2 gas flow rate from 0.1 to 0.5 L/min is statistically significant. The composition of pyrolysis gas as a function of N2 flow rate is shown in Table 4. The major gaseous product are same as obtained in Table 3. There is no significant change in the percent composition of gaseous product in case of different flow rate of N2. CO2 was the major component among the present gases accounting to about 60e70%. However, the molecular weight of gas increased from 43.77 g/mol to 254.15 g/mol when the flow rate was increased from 0.1 to 0.5 L/min. 3.5. Influence of heating rate on pyrolysis product yield The third group of experiments was conducted to determine the effect of heating rate on the pyrolysis yields. These experiments were conducted with four different heating rates of 25, 50, 75 & 100 C/min at a fixed pyrolysis temperature of 450 C and were swept with a gas flow rate of 0.2 L/min. In fast pyrolysis the liquid product yield is higher since the fast heating rates allow the conversion of thermally unstable biomass compounds to a liquid product due reduced heat and mass transfer limitations, before they form undesired coke [2,33]. Experimental results are given in Table 5 and Fig. 5. Secondary reactions will occur due to increase in residence time in pyrolysis. Higher liquid products are produced in fast pyrolysis compared to slow pyrolysis. Increase in heating rate from 25 C/min to 50 C/min resulted in an increase of bio-oil yield from 42.28% to 43.15%, later decreased to 37.13% when increased from 75 C/min to 100 C/min. With the rise in heating rate from 25 to 100 C/min, the yield of char decreased from 30.33% to 24.67% and yield of gas increased from 20.54% to 21.03%. From Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
9
Table 5 Influence of heating rate on pyrolysis product yield at fixed N2 flow rate and 450 C. Heating rate
Muffle furnace Temperature Yield wt.%
Time taken to reach 450 C C Total liquid Organics Water Char Gas Loss Closure (%) Reaction time N2 gas Syn-gas Time (seconds) Gas Selectivity H2 CO2 CO CH4 C2H6 C3H8 g/mol
Time (min) Flow rate L/min Flow rate L/min Vapour Residence Time Sys-gas composition analysis
Molecular weight
C/min
25
50
75
100
18 450 42.28 23.17 19.11 30.33 20.54 6.85 93.5 35 0.2 0.106 0.98 mol% 5.28 66.89 19.83 5.16 0.78 2.06 99.72
9 450 43.15 24.66 18.49 28.74 21.09 7.02 92.98 34 0.2 0.113 0.92 mol% 5.33 66.11 19.86 5.19 0.81 2.10 87.75
6 450 40.02 22.15 18.07 26.28 21.02 12.68 87.52 32 0.2 0.119 0.82 mol% 5.44 65.84 19.89 5.17 0.85 2.83 79.13
4.5 450 37.13 19.45 17.68 24.67 21.03 17.17 82.83 31 0.2 0.123 0.78 mol% 5.45 65.53 19.87 5.22 0.94 2.99 74.06
Fig. 5. Influence of heating rate on pyrolysis product yield at fixed N2 gas flow rate and 450 C temperature.
the experiment, it is clear that at higher heating rates the yield of char decreases compared to lower heating rates, due to faster depolymerization of solid biomass to primary volatiles [34]. Therefore, from the experiment it can be concluded that the optimum yield of bio-oil is possible at a pyrolysis temperature of 450 C, at a heating rate of 50 C/min with a sweeping gas flow rate of 0.2 L/min. The statistical analysis of the data from Table 5, regarding variation of heating rate on pyrolysis product yield, indicate that the variation of heating rate on pyrolysis yield at constant temperature (450 C) and N2 gas (0.2 L/min) flow rate is not significant, since the value of P is above 0.05. However, the value of p was <0.05, in case of char, gas and loss respect to heating rate, which indicated that the mean difference is significant at 0.05 level. The composition of pyrolysis gas as a function of different heating rate is shown in Table 5. The major gaseous product is same as obtained in Tables 3 and 4. There is no significant change in the percent composition of gaseous product in case of different heating rates. CO2 was the major component among the present gases accounting to about <70% >60%. However, the molecular weight of gas decreased from 99.72 g/ mol to 74.06 g/mol when the heating rate was increased from 25 C/min to 100 C/min. 3.6. Characterization of bio-oil The physical and chemical characteristic of bio-oil is represented in Table 6. The potentiality of bio-oil to be used as a fuel depends on its heating value. The HHV of A. philoxeroides weed bio-oil was found to be 8.88 MJ/kg, which was little more than the result obtained by WuJun Liu et al. [10]. The elemental values in Table 1, are lower compare to raw material, so its energy density will also be less. Since, biomass derived fuel contains higher oxygen content compared to fossil fuel, therefore its heating value and energy density will be inferior compare to commercial fuels such as diesel and petrol and will also lead to ignition delay [35]. The average chemical composition of bio-oil was found to be CH4.20 N0.06 O2.10 P0.0024. The H/C ratio of bio-oil is somewhat closer to methane. The water content in bio-oil was found to 18.49 wt.% Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
10
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14 Table 6 Physical properties of bio-oil obtained at 450 C. Properties
Bio-oil
Carbon Hydrogen Nitrogen Phosphorous* Oxygen H/C O/C N/C P/C Empirical formula Viscosity @ 100 C Density Flash point Fire point Appearance Odour Miscibility Initial boiling point Final boiling point
23.61 8.27 1.74 0.07 66.31 4.20 2.10 0.06 0.0024 CH4.20 N0.06 O2.10 P0.0024 4.12 cSt 0.9473 kg/m3 52 C 67 C Dark brown Smoky CH4, CHCl3, CH2Cl2, etc 94 370
*
EDX analysis.
(450 C, 0.2 L/min at 50 C/min) of the pyrolysis bio-oil, due to high oxygen content of biomass structure consisting mainly of cellulose, hemicellulose and lignin [36]. The bio-oil has lower ash content, which means that it can use as clean fuel oil. The pH of the bio-oil was found to be 6.26, which is lower due the presence of organic acid. The acid number of the bio-oil was found to be 41.26 mg KOH g1. In comparison to conventional transportation fuel (Table 7) the viscosity and density of the A. philoxeroides bio-oil was found to be more. Higher viscosity and density may lead to poor flow characteristics, stability and will cause high-pressure drops in pipelines leading to higher pumping costs and atomization in engine [37]. Higher density and viscosity of the bio-oil can be modified by blending with different commercial fuel or by upgrading with help of catalyst addition. The initial boiling point of the pyrolysis oil was 94 C, which means that the liquid contains considerable amount of volatile matter. The pyrolysis oil consists of wide verity of chemicals, which can be identified by determining the organic groups by FT-IR analysis represented in Fig. 6. Broad and strong absorbance spectra of A. philoxeroides was observed at 3220.76 cm1 indicates the presence of Table 7 Comparison of fuel properties of Alternanthera philoxeroides weeds bio-oil with conventional transportation fuels. Properties fuels
Specific gravity 15/15 C
Kinematic viscosity @ 40 C
Flash point ( C)
Fire point ( C)
HHV (MJ/kg)
Initial boiling point ( C)
Final boiling point ( C)
Alternanthera philoxeroides weed bio-oil Gasoline [41] Diesel [41]
0.9486
24.67
52
67
8.88
94
370
0.72e0.78 0.82e0.85
0.400e0.550 [39] 2e5.5
43 53e80
53 to 60 [38] 65e95 [40]
42e46 42e45
27 172
225 350
Fig. 6. FT-IR of bio-oil obtained at 450 C.
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
11
alcohols and phenols. The CeH stretching vibration at 2956.43, 2923.33 cm1 and 2853.06 cm1 indicates the presence of methylene group. The PeH sharp vibration at 2361.60 cm1 and 2341.12 cm1 indicates the presence of phosphine. The presence of carboxyl group of aldehyde and ketone can be seen at a vibration of 1704.62 cm1. The C]C stretching vibration at 1659.92 cm1, 1608.67 cm1, 1559.34 cm1, 1556.62 cm1, & 1514.91 cm1 indicated the presence of alkenes and aromatics compounds. The N]O asymmetric stretch vibration at 1514.31 cm1 indicated the presence of nitro groups. The presence of nitro group in bio-oil will lead to the formation of aliphatic nitrogenous compounds. The CeH deformation at 1455.92 cm1 indicated the presence of alkanes. The CeO vibration at 1377.61 cm1 indicates the presence of carboxylic acids. The AreN stretching vibration at 1326.51 indicated the presence of amines. The CeO stretching vibration at 1272.29, 1242.21 cm1 & 1221.03 cm1, indicates the presence of ethers. The OeH bending and C]C stretching from 975 to 525 cm1 indicates the presence of mono, polycyclic, substituted aromatics rings in bio-oil. Out of many compounds present in bio-oil only 26 compounds are enlisted in Table 8. The various organic products present in the bio-oil (Fig. 7) were Alcohol, Aldehyde, Amine, Ketone, Alkenes & Alkanes. The bio-oil from A. philoxeroides contains 20.59% of phenols, 11.07% amines, 14.59% aldehydes, 15.07% ketones, 16.44% alkenes, and 15.22% alkanes. The higher percentage of phenols in the bio-oil is due to the decomposition of lignin and impurities present in water [42,43]. The main phenolic compounds present in bio-oil are phenols, 2-methoxy-
Table 8 GCeMS of bio-oil at 450 C. Retention time (min)
Compound
Area %
Classification
Formula
4.52 4.79 4.86 5.96 6.25 7.37 8.83 9.07 9.27 10.05 11.32 11.37 12.32 14.37 14.51 16.99 17.03 18.72 18.76 19.09 20.66 21.78 22.136 23.80 24.08 25.60 26.32
Phenol Acetic acid Ethylene-di-amine Benzylamine 2-methoxy-phenol 2,4,5-Trimethoxy-benzaldehyde 3-Methyl-1,2-cyclopentanedione 1-methyl-2-nitro-benzene Pyrocatechol 2-ethenyl-naphthalene 5-Methylfuran-2-carbaldehyde Cyclopent-2-enone 2-Furylcarboxaldehyde 2,4,6-Trimethoxyacetophenone 1,3,5-trimethyl-benzene 2,4,4-Trimethyl-2-pentylamine Isothiocyanato-Methane Tridecane 1-Hydroxy-2-propanone 2,6-dimethyl-phenol Triphenyl-silanol 2,4-di-tert-butyl-phenol Tetracosane Resorcinol 2,3,6-trimethylnaphalene 4,5-Dimethyl-4,5-dihydro-1H-pyrazole 3,4,5-trimethoxy-a-methyl-phenethylamine
5.15 2.54 1.84 5.43 4.51 3.53 2.89 4.19 2.14 5.79 3.82 2.73 6.14 2.22 3.15 1.74 2.01 4.58 7.23 2.17 2.53 4.18 3.45 2.05 3.31 1.10 2.06
Alcohol Carboxylic acid Amine Amine Alcohol Aldehyde Ketone Alkene Alcohol Alkene Aldehyde Ketone Aldehyde Ketone Alkene Amine Alkane Alkane Ketone Alcohol Alcohol Alcohol Alkane Alcohol Alkene Aldehyde Amine
C6H6O C2H4O2 C2H8N2 C7H9N C7H8O2 C10H12O4 C6H8O2 C7H7NO2 C6H6O2 C12H10 C6H6O3 C5H6O C5H4O2 C11H14O4 C9H12 C8H19N C2H3NS C13H28 C3H6O2 C9H12 C18H16OSi C14H22O C24H50 C6H6O2 C13H14 C8H10N2 C12H19NO3
Fig. 7. GCeMS of bio-oil at 450 C.
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
12
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
Phenol, 2, 6-dimethyl-Phenol, and 2,4-di-tert-Butyl-Phenol. Acid present in bio-oil will lead to corrosion. If acids can be separated from biooil, they have the potential to be used as a chemical feedstock. The presence of oxygenated compounds in bio-oil will have a negative effect in the heating value of bio-oil. In order to utilize bio-oil effectively for energy generation, proper separation of oxygenated compounds is necessary. The presence of nitrogenous compounds in bio-oil is due to the conversion of amino acids into amines. The carbon chain length in bio-oil ranges from C2eC24, which is similar to conventional transportation fuel. 3.7. Characterization of bio-char The carbon content and calorific value of bio-char was found to be more in comparison to biomass and bio-oil, which supplements its usage as activated carbon and solid fuel. Increase in fixed carbon content is due to low volatile matter content in bio-char, so less liberation of fixed carbon. The elemental analysis of bio-char showed significant decrease in oxygen and slight variation in hydrogen, nitrogen and phosphorous content. Lower oxygen content helps to increase in the percentage of carbon content in A. philoxeroides sample during pyrolysis. The proximate and ultimate analysis of bio-char is represented in Table 9. The functional group characterization of bio-char obtained at 450 C is shown in Fig. 8. Broad and strong absorbance spectra of A. philoxeroides was observed in the region between 3600 and 3400 cm1 indicating the presence of carbohydrates and proteins. With increase in temperature, the spectrum reduced, due to conversion of carbohydrates and protein during the reaction. Strong CeH stretching (methyl and methylene groups) absorbance spectra can be seen in bio-oil, where as weak aliphatic CeH stretching can be seen in case of bio-char due to heat resistance RCH2CH3 structures [44]. The vibration at 1568.49 and 1557.64 cm1 indicates the presence of aromatic rings. The OeH bending and C]C stretching from 975 to 525 cm1 indicates the presence of mono, polycyclic, substituted aromatics rings in bio-char. At elevated temperature most of the functional groups will vanished and only char will remain in the form of aromatic polymer carbon atom [45]. Chemicals adsorption, reactivity and combustion property depends on the surface area of bio-char. The surface area of the biomass was found to be 36.5 m2/g and the surface area of the bio-char increased to 123.71 m2/g after pyrolysis at 450 C. Due to high surface area compare to its biomass, the char could be used for adsorption. However, with increase in temperature of pyrolysis up-to 550 C the surface area of bio-char increased to 375.2 m2/g. The surface area of bio-char increased with rise in temperature due release of volatile matter resulting from secondary decomposition. The SEM images of biomass and bio-char at 5KX magnification at an acceleration voltage of 15 KV are given in Fig. 9. The comparison of both the SEM images of biomass and bio-char highlights the morphological changes happening after devolatization steps. The release of Table 9 Proximate and ultimate analysis of bio-char obtained at 450 C. Properties
Bio-char
Moisture, wt.% Volatile matter wt.% Ash content wt.% Fixed carbon content wt.% Carbon Hydrogen Nitrogen Oxygen Phosphorous H/C O/C N/C P/C HHV (MJ/kg) Empirical formula
0.63 16.68 31.84 50.85 52.39 3.66 4.29 39.11 0.55 0.84 0.56 0.07 0.0084 20.41 CH0.84 N0.07 O0.56 P0.0084
Fig 8. FT-IR of bio-char at 450 C.
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
13
Fig 9. SEM images of (a) biomass and, (b, c) bio-char obtained at 450 C and 550 C.
volatile matter at elevated temperature leads to formation of rough textures on the surface and heterogeneous distribution of pores in biochar. The increase in pores size and surface is due to the fast thermal decomposition of lignin at elevated temperatures. The average pore diameter at 450 C was 4.83 mm and later increased to 11.64 mm at 550 C. The increase in the pore diameter with rise in temperature was due to the coalescence of smaller pores, which leads to large internal cavities and more open structures [45e47]. 4. Conclusion In this study, A. philoxeroides biomass was found to be feasible for bio-oil production from pyrolysis. ❖ The maximum liquid yield was found to be 40.10% at a sweeping gas flow rate of 0.1 L/min at 450 C, at a constant heating rate of 25 C/min. ❖ However, with varying sweeping gas flow rate from 0.1 to 0.5 L/min, the yield of bio-oil increased to 42.28% only at a sweeping gas flow rate of 0.2 L/min at a constant heating rate of 25 C/min. ❖ With varying heating rate, the yield of bio-oil increased to 43.15% at a heating rate of 50 C/min. ❖ Loss percentage can be minimised by the use of chillers, cryogenic medium, etc. ❖ The percentage of phenol and oxygenated compounds were more in bio-oil analysed by GCeMS and FT-IR. ❖ The carbon chain length in bio-oil lied from C2eC24 and its empirical formula was found to be CH4.20N0.06O2.10P0.0024. ❖ The bio-char attained during pyrolysis had a higher calorific value of 20.41 MJ/kg compare to biomass and bio-oil. The surface area and pore size of bio-char increased from 4.83 mm, 123.71 m2/g to 11.64 mm, 375.2 m2/g with rise in temperature. ❖ From the analysis, it can be concluded that the obtained bio-oil can be utilized as a fuel by upgrading or blending with other fuels. The bio-char has the potential to be utilised as a solid fuel. References [1] A.H. Gerhauser, A.V. Bridgwater, Production of renewable phenolic resins by thermochemical conversion of biomass, Renew. Sust. Energy Rev. 12 (2008) 2092e2116. € [2] Bas¸ak Burcu Uzun, Esin Apaydin-Varol, Funda Ates¸, Nurgül Ozbay, Ays¸e Eren Pütün, Synthetic fuel production from tea waste: characterisation of bio-oil and bio-char, Fuel 89 (2010) 176e184. [3] G. van Rossum, S.R.A. Kersten, W.P.M. van swaaij, Ind. Chem. Res. 46 (2007) 3959. [4] S. Yorgun, S. Sensoz, O.M. Kockar, Characterization of the pyrolysis oil produced in the slow pyrolysis of sunflower-extracted bagasse, Biomass Bio-energy 20 (2001) 141e148. [5] S. Vitolo, M. Seggiani, P. Frediani, G. Ambrosini, L. Politi, Catalytic upgrading of pyrolytic oils to fuel over different zeolites, Fuel 78 (1999) 1147e1159. [6] S. Zhang, Y. Yan, T. Li, Z. Ren, Upgrading of liquid fuel from the pyrolysis of biomass, Bioresour. Technol. 96 (2005) 545e550. [7] A.V. Bridgwater, Biomass pyrolysis technologies, in: G. Grassi, G. Gosse, G. Dos Santos (Eds.), Biomass Energy Ind. Environ. 5th E.C. Conference, Elsevier, London, New York, 1990, pp. 2489e2496. [8] C. Di Blasi, Modeling chemical and physical processes of wood and biomass pyrolysis, Prog. Energy Combust. 34 (2008) 47e90. lu, E. Tetik, E. Gollu, Biofuel production using slow pyrolysis of the straw and stalk of rapeseed plant, Fuel Process. Technol. 59 (1999) 1e12. [9] F. Karaosmanog [10] Wu-Jun Liu, Fan-Xin Zeng, Hong Jiang, Hang-Qing Yu, Total recovery of nitrogen and phosphorus from three wetland plants by fast pyrolysis technology, Bioresour. Technol. 102 (3) (November 2011) 3471e3479. [11] Kittiphop Promdee, Tharapong Vitidsant, Supot Vanpetch, Comparative study of some physical and chemical properties of bio-oil from Manila grass and water hyacinth transformed by pyrolysis process, Int. J. Chem. Eng. Appl. 3 (1) (February 2012). [12] Nazim Muradov, Beatriz Fidalgo, Amit C. Gujar, Ali T-Raissi, Pyrolysis of fast-growing aquatic biomass e Lemna minor (duckweed): characterization of pyrolysis products, Bioresour. Technol. 101 (2010) 8424e8428. [13] Seung-Soo Kim, Foster A. Agblevor, Thermogravimetric analysis and fast pyrolysis of Milkweed, Bioresour. Technol. 169 (2014) 367e373. [14] J.K. Maheshwari, Alligator weed in Indian lakes, Letter to nature, Nat. 206 (19 June 1965) 1270. [15] Ankit Agrawalla, Sachin Kumar, R.K. Singh, Pyrolysis of groundnut de-oiled cake and characterization of the liquid product, Bioresour. Technol. 102 (22) (November 2011) 10711e10716. [16] Beena Patel, Bharat Gami, Biomass characterization and its use as solid fuel for combustion, Iran. J. Energy Environ. 3 (2) (2012) 123e128. [17] Haiping Yang, Rong Yan, Hanping Chen, Dong Ho Lee, Chuguang Zheng, Characteristics of hemicellulose, cellulose and lignin pyrolysis, Fuel 86 (2007) 1781e1788. [18] A. Friedl, E. Padouvas, H. Rotter, K. Varmuza, Prediction of heating values of biomass fuel from elemental composition, Anal. Chim. Acta 544 (1e2) (15 July 2005) 191e198. [19] T. Cornelissen, M. Jans, J. Yperman, G. Reggers, S. Schreurs, R. Carleer, Flash co-pyrolysis of biomass with polyhydroxybutyrate: Part 1. Influence onbio-oil yield, water content, heating value and the production of chemicals, Fuel 87 (2008) 2523e2532.
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
14
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
[20] Rahul Singh Chutia, Rupam Kataki, Thallada Bhaskar, Characterization of liquid and solid product from pyrolysis of Pongamiaglabradeoiled cake, Bioresour. Technol. 165 (2014) 336e342. [21] Tanmya Rout, Debalaxshmi Pradhan, R.K. Singh, Namrata Kumari, Exhaustive study of products obtained from coconut shell pyrolysis, J. Environ. Chem. Eng. 4 (3) (September 2016) 3696e3705. [22] Haibo Xie, Nicholas Gathergood, The Role of Green Chemistry in Biomass Processing and Conversion, 2012, pp. 45e46. [23] N.K. Nayan, S. Kumar, R.K. Singh, Production of the liquid fuel by thermal pyrolysis of neem seed, Fuel 103 (2013) 437e443. [24] O. Onay, O. Mete Kockar, Fixed-bed pyrolysis of rapeseed (Brassica napus L.), Biomass Bioenergy 26 (3) (2004) 289e299. [25] P. Kim, A. Johnson, C.W. Edmunds, M. Radosevich, F. Vogt, T.G. Rials, N. Labbe, Surface functionality and carbon structures in lignocellulosic-derivedbiochars produced by fast pyrolysis, Energy Fuels 25 (10) (2011) 4693e4703. [26] J.M. Encinar, J.F. Gonzalez, J. Gonzalez, Fixed-bed pyrolysis of Cynaracardunculus L. product yields and compositions, Fuel Process. Technol. 68 (3) (2000) 209e222. €l Becidan, Øyvind Skreiberg, Johan E. Hustad, Products distribution and gas release in pyrolysis of thermally thick biomass residues samples, J. Anal. Appl. [27] Michae Pyrolysis 78 (1) (January 2007) 207e213. ndez, A. Domínguez, Y. Ferna ndez, J.J. Pis, Evidence of self-gasification during the microwave-induced pyrolysis of coffee hulls, Energy Fuels 21 (1) (2007) [28] J.A. Mene 373e378. [29] Haiping Yanga, Rong Yanb, Hanping Chena, Dong Ho Leeb, David Tee Liang, Chuguang Zhenga, Pyrolysis of palm oil wastes for enhanced production of hydrogen rich gases, Fuel Process. Technol. 87 (10) (October 2006) 935e942. [30] B.B. Uzun, A.E. Putun, E. Putun, Composition of products obtained via fast pyrolysis of olive-oil residue: effect of pyrolysis temperature, J. Anal. Appl. Pyrolysis 79 (2007) 147e153. [31] A.E. Putun, N. Ozbay, E. Apaydin-Varol, B.B. Uzun, F. Ates, Rapid and slow pyrolysis of pistachio shell: effect of pyrolysis conditions on the product yields and characterization of the liquid product, Int. J. Energy Res. 31 (2007) 506e514. [32] R. Maggi, B. Delmon, Comparison between slow and flash-pyrolysis oils from biomass, Fuel 73 (1994) 671e677. [33] Lecture-10, Principles of Pyrolysis. http://eagri.tnau.ac.in/eagri50/AENG352/lec10.pdf. [34] G. Chen, Q. Yu, K. Sjostrom, Reactivity of char from pyrolysis of birch wood, J. Anal. Appl. Pyrolysis 40e41 (1997) 491e499. [35] Lu. Qjang, Wenzhi Li, Xifeng Zhu, Overview of applications of biomass fast pyrolysis oil, Energy Convers. Manag. 50 (2009) 1376e1383. [36] N. Worasuwannarak, T. Sonobe, W. Tanthapanichakoon, Pyrolysis behaviours of rice straw, rice husk and corncob by TG-MS technique, J. Anal. Appl. Pyrolysis 78 (2007) 265e271. [37] www.ilpi.com/msds/ref/flashpoint.html. [38] www.engineersedge.com/fluid_flow/kimematic-viscousity-table.htm. [39] Vikranth Volli, R.K. Singh, Production of bio-oil from de-oiled cakes by thermal pyrolysis, Fuel 96 (2012) 579e585. [40] T. Siengchum, M. Isenberg, S.S.C. Chuang, Fast pyrolysis of coconut biomassdan FTIR study, Fuel 105 (2013) 559e565. [41] Petroleum Product Surveys, Motor Gasoline, Summer, Winter 1986/1987, National Institute for Petroleum and Energy Research, 1986. http://www.afdc.energy.gov/afdc/ pdfs/fueltable.pdf. [42] B. Hasanah, The chemical composition and physical properties of the light and heavy tar resulted from coconut shell pyrolysis, J. Pure Appl. Chem. Res. 1 (2012) 26e32. [43] B. Sukhbaatar, P.H. Steele, L.L. Ingram, M.G. Kim, An exploratory study on the removal of acetic and formic acids from bio-oil, BioResources 4 (2009) 1319e1329. [44] Peigao Duan, Zhoufan Chang, Yuping Xu, Xiujun Bai, Feng Wang, Lei Zhang, Hydrothermal processing of duckweed: effect of reaction conditions on product distribution and composition, Bioresour. Technol. 135 (2013) 710e719. [45] V. Gomez-Serrano, P.M. Alvarez, J. Jaramillo, F.J. Beltran, Formation of oxygen complexes by ozonation of carbonaceous materials prepared from cherry stones, I, Therm. Eff. Carbon 40 (2002) 513e522. [46] M. Guerrero, M.P. Ruiz, M.U. Alzueta, R. Bilbao, A. Millera, Pyrolysis of eucalyptus at different heating rates: studies of char characterization and oxidative reactivity, J. Anal. Appl. Pyrolysis 74 (2005) 307e314. [47] E. Apaydin-Varol, E. Putun, A.E. Putun, Slow pyrolysis of pistachio shell, Fuel 86 (2007) 1892e1899.
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
Contents lists available at ScienceDirect
Journal of the Energy Institute journal homepage: http://www.journals.elsevier.com/journal-of-the-energyinstitute
Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char Neelanjan Bhattacharjee, Asit Baran Biswas* Department of Chemical Engineering, University of Calcutta, UCSTA, 92 A. P. C. Road, Kolkata 700 009, West Bengal, India
a r t i c l e i n f o
a b s t r a c t
Article history: Received 21 October 2016 Received in revised form 22 February 2017 Accepted 27 February 2017 Available online xxx
In the present work, fast pyrolysis of Alternanthera philoxeroides was evaluated with a focus to study the chemical and physical characteristics of bio-oil produced and to determine its practicability as a transportation fuel. Pyrolysis of A. philoxeroides was conducted inside a semi batch quartz glass reactor to determine the effect of different operating conditions on the pyrolysis product yield. The thermal pyrolysis of A. philoxeroides were performed at a temperature range from 350 to 550 C at a constant heating rate of 25 C/min & under nitrogen atmosphere at a flow rate of 0.1 L/min, which yielded a total 40.10 wt.% of bio-oil at 450 C. Later, some more sets of experiments were also performed to see the effect on pyrolysis product yield with change in operating conditions like varying heating rates (50 C/min, 75 C/min & 100 C/min) and different flow rates of nitrogen (0.2, 0.3, 0.4 & 0.5 L/min). The yield of biooil during different heating rate (25, 50, 75 and 100 C/min) was found to be more (43.15 wt.%) at a constant heating rate of 50 C/min with 0.2 L/min N2 gas flow rate and at a fixed pyrolysis temperature of 450 C. The High Heating Value (HHV) value of bio-oil (8.88 MJ/kg) was very less due to presence of oxygen in the biomass. However, the high heating value of bio-char (20.41 MJ/kg) was more, and has the potential to be used as a solid fuel. The thermal degradation of A. philoxeroides was studied in TGA under inert atmosphere. The characterization of bio-oil was done by elemental analyser (CHNS/O analyser), FTIR, & GC/MS. The char was characterized by elemental analyser (CHNS/O analysis), SEM, BET and FT-IR techniques. The chemical characterization showed that the bio-oil could be used as a transportation fuel if upgraded or blended with other fuels. The bio-oil can also be used as feedstock for different chemicals. The bio-char obtained from A. philoxeroides can be used for adsorption purposes because of its high surface area. © 2017 Energy Institute. Published by Elsevier Ltd. All rights reserved.
Keywords: A. philoxeroides biomass Pyrolysis Bio-oil Bio-char
1. Introduction Our present world relies on energy, obtained from different sources of fossil fuels. Due to vast expanding urbanization in cities throughout the world, reliability on fossils fuels has also plummeted. Hunger for energy needs is depleting fossil fuel sources day by day. With increase in energy demands, rise in petroleum prices and environmental related problems alternative way needs to be implemented. This crisis can only be overcome by the use of biomass, which is the third largest energy source present in today's world. For the production of conventional hydrocarbon transportation fuels, the only renewable source of fixed carbon is biomass [1]. Biomass generally consists of cellulose, hemicellulose, & lignin, which are good source of fuels and chemicals. Biomass can be converted into transportation fuels by two major processes viz. (a) thermo-chemical (combustion, gasification, pyrolysis, liquefaction, hydrogenation, carbonization and torrefaction) and (b) biochemical (anaerobic and aerobic fermentation to produce ethanol, butanol, methanol, etc.). Different structures of biomass decomposed at various temperature ranges. Lignin decomposes at higher temperature range compare to cellulose and hemicellulose, which decomposes at lower temperature range. Hence, lignin gains thermal stability during thermal degradation [2]. Out of these processes
* Corresponding author. E-mail address: [email protected] (A.B. Biswas). http://dx.doi.org/10.1016/j.joei.2017.02.011 1743-9671/© 2017 Energy Institute. Published by Elsevier Ltd. All rights reserved.
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
2
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
pyrolysis is more efficient to convert biomass into three different states of matter (solid: char, liquid: bio-oil, gas: Syn-gas). The bio-oil obtained from different biomass via thermo-chemical conversion, consists more than 300 organic compounds. Bio-oil thus obtained from thermo-chemical conversion is a good source of feedstock for different chemical manufacturing, and also has higher energy content compare to biomass, and can be transported easily. Another advantage of bio-oil is that it is cleaner than biomass, since many impurities (minerals and metals) are left in the bio-char after pyrolysis [3]. The bio-oil can be upgraded to refined fuels, which can be use directly or blended with different petroleum products or use as chemical feedstock [4]. Due to their high viscosity, poor heating value, corrosiveness and instability, their direct use as conventional fuels may present some difficulties [5,6]. The bio-char can also be used as solid fuel or used for other applications such as soil modification, manufacturing of activated carbon and bio-carbon electrodes or used in metallurgical and leisure industries [7e9]. The Syn-gas which is composed of methane, carbon dioxide, hydrogen, carbon monoxide, trace amount of propane and other compounds, can be used to fire boilers for electricity generation or can be used as an alternative to Liquid petroleum gas. Invasive aquatic weeds possess problem to native flora and fauna. They have capability to absorb all nutrients from wetlands within two weeks and destroy all native plants, causing huge problems [10]. They pose problems by blocking waterways, jamming turbines in hydel power plants, reducing native fish population, inflecting water, providing shelter to disease causing insects, etc. Therefore, they should be destroyed or converted into organic manure and transportation fuels. There have been many studies on the pyrolysis of different weeds to produce bio-oil and other products. Kittiphop Promdee et al. [11], carried pyrolysis experiments of Manila Grass and water hyacinth in tube furnace reactor in N2 atmosphere in temperature range of 450e600 C to study the effect of feeding rate, the control gas flow, the temperatures in reactor and reactor operate on pyrolysis product yields. Nazim Muradov et al., carried the pyrolysis of fast-growing aquatic biomass e Lemna minor (commonly known as duckweed) in a quartz tube reactor purged with argon gas (36e150 ml/min) at temperature range from 400 to 700 C with the emphasis on the characterization of main products of pyrolysis. During the experiment, it was observed that even at relatively low rates of pyrolysis (at 500 C) it is possible to obtain in excess of 40 wt.% of bio-oil from dry duckweed. Faster pyrolysis rates would significantly increase the bio-oil yield [12]. Seung-Soo Kim et al.; carried the pyrolysis of Milkweed in a thermo-gravimetric analyser and a bubbling fluidized bed reactor in nitrogen atmosphere at a gas flow rate of 40 ml/min, in a pyrolysis temperature maintained between 425 C and 550 C to see the effect of temperature on pyrolysis yield. From the experiment Seung Kim et al. concluded that unlike other lignocellulosic biomass, milkweed has a higher HHV (>30 MJ/kg) and higher density and pH compared to other biomass, and can be easily converted to hydrocarbon fuel [13]. P. Manara et al. carried the pyrolysis of red seaweed residues by means of a thermo-gravimetric analyser and a fast pyrolysis captive sample reactor at a range of 450e650 C in helium atmosphere. P. Manara found that product yield distribution is a function of the feedstock and the temperature & at medium temperature (550 C), pyrolysis gives higher oil (reaching values of 70 wt.%) yields and lower char yields. Alternanthera philoxeroides, (Martius) Grisebach, a South American weed of the family amaranthaceae has also been discovered in Madhya Pradesh, Maharashtra, Assam, Meghalaya, Arunachal Pradesh, Bihar, Haryana, Himachal Pradesh, Karnataka, Kerala, Orissa, Tamil Nadu, Uttarakhand, Uttar Pradesh and West Bengal. Like several other American weeds, these invasive weeds might have reached India along with some packing material during the Second World War. The species was collected for the first time in India near an aerodrome at Calcutta [14]. Alligator weeds have a negative impact on waterways; it reduces oxygen content, light penetration in water also reduces water flow. It also has a negative impact on zoological and botanical habitat such as fish and birds, death of other water plants. It is rather difficult to control and helps in the breeding of mosquitoes. In this study, A. philoxeroides was selected as feedstock for bio-fuel production and objectives of the study are as follows: 1. Determine the effect of pyrolysis temperature, sweeping gas flow rates, & heating rates on product yield. 2. Characterization of the liquid product obtained at ideal pyrolysis condition and to investigate whether it can be used as an alternative of fossil fuels or as feedstocks for different chemical manufacturing. 3. Characterization of the bio-char obtained as a result of pyrolysis and find its applicability as a solid fuel.
2. Experimental setup and procedure 2.1. Raw material preparation The biomass sample (feedstock) used in the study was obtained from Howrah district, West Bengal, India. Prior to use, the biomass was thoroughly washed to remove any foreign materials that came with the plant. The cleaned sample was then sun dried for 7 long days and later dried in a hot air oven at 100 ± 5 C for 4 h to remove all unbound moisture. The dried sample was then grinded and passed through a screen of 72 B.S. The screened samples were used for the fast pyrolysis process. 2.2. Pyrolysis system The pyrolysis was carried out in the experimental setup given in Fig. 1. The glass reactor was 12.7 cm in height and has 3 cm of internal diameter. The glass reactor was connected to a fractionating column, having dimension of 30 cm in height and internal diameter of 3 cm. The fractionating column was insulated up to condenser opening to avoid heat loss and pre-condensation. The reactor was heated externally by 800 Watts electric muffle furnace. Temperature within the reactor was measured by a k-type thermocouple attached to an external PID controller. Another PID controller controlled the heating rate and temperature of furnace. The outlet of the reactor was connected to a series of condensers to condense the vapours coming out of the reactor. The condensate was collected in measuring cylinder after the experiment. The yields of the liquid product and chars were determined by weighing. The Syn-gas volume was measured by downwards displacement of water. The compositional analysis of Syn-gas by GCeMS gave out the exact mol %, of the different gases present. Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
3
Fig. 1. Schematic diagram of pyrolysis experimental setup. 1) Nitrogen cylinder; 2) Rotameter; 3) K-type thermocouple connected to PID controller; 4) Insulated fractionation Column; 5) Muffle Furnace; 6) Pyrex Glass Reactor; 7) PID controller; 8) Ice cooled 30 L water tank; 9) Submersible Pump; 10) Liebig Condenser; 11) Separating funnel; 12) Condenser; 13) Condensers; 14) Gas vent.
Liquid yieldð%Þ ¼
Char yield % ¼
gas yield % ¼
wt of liquid; grams 100 wt of dry biomass; grams
char weight 100 feed weight
Sum of the masses of every component of Syn gas 100 wt of dry biomass; grams
Loss % ¼ 100 ðLiquid yield þ char þ GasÞ
(1)
(2)
(3) (4)
The liquid yield consists to two different phases, the top layer is the bio-oil and bottom one is the aqueous layer. The bio-oil was separated from the aqueous phase with the help of separating funnel. The separated bio-oil was later bottled and kept for further analysis. Syn-gas produced during different temperatures of pyrolysis was measured by water displacement method and was collected overtime for compositional analysis. The pyrolysis experiments were performed thrice for better results. One-way analysis of variance (ANOVA) was conducted in origin 8 using the data obtained from the pyrolysis of A. philoxeroides. To check whether the values (pyrolysis yield) obtain because of difference in temperature, variation in N2 gas flow rate and effect of different heating rate are statically significant, the probability P value needs to be determined. If P values are small, then it is doubtful that the differences in the values of dependent variables observed are coincidental and due to random sampling [12]. 2.3. Characterization 2.3.1. Proximate analysis The proximate analysis of the dry biomass sample (feedstock) was determined by IS: 1350-1(1984) method for the evaluation of moisture, ash, volatile and fixed carbon content. Proximate analysis is an easiest way to determine the fuel quality of a solid material. High moisture & ash content will have a negative effect on heating rate of biomass and lower combustion efficiency, high volatile content of a solid fuel is not appreciable because it will require higher oxygen during combustion [15]. 2.3.2. Ultimate analysis The ultimate analysis or elemental analysis of the dry biomass sample was determined by using ZEISS EVO 18 (Germany) and Perkin Elmer 2400 II CHNS/O; analyser for the evaluation of carbon, hydrogen, nitrogen, oxygen, phosphorous, and other elements. Ultimate analysis helps in evaluating theoretical air required for complete combustion, volume of fuel gas generated per kg of fuel fired, water vapour & sulphur content of flue gas. Carbon and hydrogen content of fuel help in the determination of calorific value, when the sum of these components is subtracted from 100, it gives oxygen percentage [16]. Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
4
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
2.3.3. Compositional analysis The compositional analysis (hemicelluloses, cellulose and lignin) of the dry biomass sample was determined by following the method prescribed by Haiping Yang et al. [17]. 2.3.3.1. Extractive analysis. The dry biomass sample of A. philoxeroides (X1) was leached with a mixture of ethyl alcohol/benzene in 1:2 volumes at room temperature for 3 h. Later a Whatman filter paper 41 was used to separate the biomass ethyl alcohol/benzene mixture. The leached biomass was then dried in a hot air oven maintained at 85 ± 5 C, for constant weight. The residue was then cooled in a desiccator and weighted again (X2). The extractive weight percentage was the calculated using the below formula:
Extractive analysisðWÞ ¼
ðX1 X2Þ 100 X1
(5)
2.3.3.2. Lignin analysis. Nearly 1 g of sample (X3) from the leached residue was transferred into a conical flask of 500 ml. Prepare a 200 ml solution of H2SO4 (98%) of 1 N and pour this solution into the conical flask. Seal the conical flask mouth with non-absorbing cotton and keep the mixture at 8e15 C for 24 h. After 24 h, add about 200 ml of double distil water into the mixture and place it inside an autoclave for 20 min (15 psi). Place a perforated porcelain funnel of 90 mm over a conical flask (500 ml) with side outlet, connected to a vacuum source for filtration. Place a weighted Whatman 41 filter paper (90 mm) over the perforated porcelain funnel and pour the mixture over it, little by little. Add double distil water in small volumes until the treated biomass becomes neutral (pH). Carefully place the Whatman 41 filter paper over a petri dish (Dia: 100 mm) and heat it inside a hot air oven maintained at 100 ± 5 C. Place the dried sample inside desiccator until constant weight is obtained (X4). The lignin weight percentage was calculated using the below formula:
Lignin Analysis ¼
ðX3 X4Þ 100 X3
(6)
2.3.3.3. Hemicellulose content. About 1 g of sample (X5) from the leached residue was transferred into a conical flask of 500 ml. Prepare a 150 ml solution of NaOH of 1 N and pour this solution into the conical flask. Seal the conical flask with non-adsorbing cotton and boil it inside an autoclave for 20 min maintained at 15 psi. Place a perforated porcelain funnel of 90 mm over a conical flask (500 ml) with side outlet, connected to a vacuum source. The residue was filtered with distilled water. This process was continued until water remained neutral, which means have to be removed ions and salts, and air-drying. Later the residue was dried in a hot oven at 100 ± 5 C for constant weight. The residue was cooled inside a desiccator and then weighted (X6). The hemicellulose wt.% is calculated by using below formula.
Hemicellulose Content ¼
ðX5 X6Þ 100 X5
(7)
2.3.3.4. Cellulose content. The cellulose weight % was calculated using the below formula:
Cellulose content ¼ 100 ðExtractive content þ Lignin content þ hemicellulose contentÞ
(8)
2.3.4. High heating value (HHV) To determine the high heating value of biomass, bio-oil & bio-char, a model used in Friedl et al. [18] was considered. The data obtained from CHNS/O analysis were put in that model, to determine the high heating value of the substances. High Heating value (MJ/kg): (3.55C2 232C 2230 H þ 51.2 C H þ 131N þ 20600)/(1000) [18].
2.3.5. pH determination Bio-char pH was determined by mixing 1 g of bio-char in 50 ml of deionised water and was sonicated for 1 h. The supernatant was tested for determining pH by a digital pH meter. 2.3.6. Thermal analysis Thermo-gravimetric analysis of the dry biomass sample was determined by using TA instrument SDT-Q600 Simultaneous TGA/DSC, V8.2 Build 100. About 5 mg of dry biomass sample was placed over an Al2O3 crucible and was heated up-to a final temperature of 600 C at 25 C/ min under inert (N2) atmosphere. In order to avoid undesirable oxidation during the thermal decomposition of dry biomass sample, a constant flow rate 0.1 L/min of N2 was maintained inside the apparatus. 2.3.7. Water content of bio-oil The water content helps in determining the quality of bio-oil, which can affect the heating values, pH, viscosity and the storage characteristics. The water content of the bio-oil was determined by dean stark apparatus using toluene as solvent. About 10 ml of bio-oil was mixed with 80 ml of toluene and placed in a 250 ml flask connected to a dean stark apparatus. Azeotropic distillation separates the water from toluene. Water left in flask was cooled before weighing [19].
Water content % ¼
Weight of water 100 weight of bio oil
(9)
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
5
2.3.8. Total acid number Presence of acid and other impurities in bio-oil can be corrosive for storage materials. The total acid number of bio-oil was determined by following ASTM D664. KOH is used as a base to neutralise the acid present in 1 g of bio-oil. About 0.3 g of bio-oil was mixed with 5 ml of diethyl ether and titrated against 0.1 M KOH solution using phenolphthalein as indicator. The acid value is determined as follows [20]:
ml of 0 : 1M KOH consumed by sample Molarity of KOH 56:1 Weight in grams of the sample
(10)
2.3.9. FT-IR The functional groups characterization of bio-oil and bio-char was conducted in a Thermo-Fisher Scientific Nicolet i35 (iD3 ATR) (FT-IR) at 4 cm1 resolution in the range of 4000e600 cm1. 2.3.10. GCeMS analysis The GCeMS analysis of the bio-oil samples was carried out using a Clarus 500 GC instrument (PerkineElmer) equipped with a TCD and was coupled to a Clarus 500 MS system (PerkineElmer). The bio-oil was dissolved in HPLC grade dichloromethane and filtered before gas chromatography and mass spectroscopy analysis. About 1 ml of sample was injected though the injecting vent for 30 s. The injecting temperature was 270 C and helium was used as a carrier gas at a flow rate of 2 ml/min. The oven temperature was maintained at 40 C during the first 4 min, later heated at a rate of 5 C/min to a final temperature of 280 C with a total run time of 45 min. A polar capillary column (BP-5) of internal diameter 0.25 mm and length 30 m was used for the analysis of chemical compounds present in the bio-oil. The compounds present in bio-oil were ionised at 70 eV in an electron impact ionization device (MS). The ion source temperature and interface temperature was maintained at 210 C & 225 C. The chromatogram data obtained after analysis were determined through National institute of science and technology (NIST) library. The Syn-gas samples collected at different pyrolysis temperature were analysed on an Agilent 6890N GC equipped with HID (H2) and TCD (CO2, CO, CH4, C2H6, & C3H8). Oven was programmed to hold at 55 C for 7 min, ramp at 20 C/ min up-to 250 C and again hold for 15 min. The detectors were maintained at 150 C and for quantification, mixture of different gases were also used. 2.3.11. SEM analysis The surface morphology of bio-char was determined using ZEISS EVO 18 SEM analyser at a magnification of 5KX with an acceleration voltage of 15 KV. The sample was pasted over a carbon tape and later coated with nano gold dust and analysed under hydrogen atmosphere. 2.3.12. BET analysis The surface area of biomass and bio char was determined using Quantacrome instruments NOVA 1000 BET surface area and pore size analyser in nitrogen atmosphere. The sample was degassed in vacuum chamber at 50 & 180 C for 5 h under nitrogen atmosphere. The degassed sample was then analysed in a Dewar containing liquid nitrogen. 3. Results and discussions 3.1. Compositional analysis of A. philoxeroides biomass powder The proximate analysis and ultimate analysis of the A. philoxeroides biomass powder is outlined in Table 1. From Table 1, it is evident that the A. philoxeroides biomass powder has lower moisture content and higher volatile matter content which will pleasant for bio-oil
Table 1 Proximate and ultimate analysis of biomass. Biomass (wt.%) Properties (proximate) Moisture content Volatile matter content Fixed carbon content Ash content Extractive content Hemicellulose content Lignin content Cellulose Properties (Ultimate) Carbon Hydrogen Nitrogen Oxygen Phosphorous (EDX analysis) HHV (MJ/kg) H/C O/C N/C P/C Empirical formula
4.16 53.87 23.81 18.16 14.71 32.13 24.15 29.01 35.26 5.79 3.65 54.94 0.36 14.85 MJ/kg 1.97 1.17 0.09 0.0082 CH1.97 N0.09 O1.17 P0.0082
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
6
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
production [21], but due to its higher ash content it will have a negative effect on bio-oil yield and will also yield more bio-char and Syn-gas [22]. Higher ash content in biomass will lead to less release of volatile matter during heating, resulting into higher bio-char content and lowering heating value of the feedstock. The biomass sample has a higher volatile matter content which can result in less loss of fixed carbon during pyrolysis [23]. HHV depends upon carbon, oxygen and ash content in the feedstock. Higher percentage of carbon content with lower percentage of oxygen and ash contents results in higher HHV of the feedstock. The HHV of the feedstock was 14.85 MJ/kg [18], which is due to higher O/C and ash content in the feedstock. 3.2. Thermal analysis of biomass The thermal stability and volatile component fraction can be determined by thermo-gravimetric analysis by monitoring the change in weight during the heating of the specimen. The analysis is mainly carried out in the presence of air, nitrogen or inert gases such as helium and argon. Thermo-gravimetric analysis of alligator weed was conducted in presence of N2 at a heating rate of 25 C/min in Fig. 2. The first region of thermal degradation of biomass occurred in between 115 C, which resulted in a weight loss of 4.93%, due to presence of moisture and few volatile. The second region of thermal degradation occurred at a temperature range of 115 Ce356 C, which resulted a total weight loss of 63.38% due to decomposition of cellulose, hemi-cellulose and formation of volatiles (carbon dioxide and carbon mono-oxide) and loss of oxygenated, nitrogen, and other elemental compounds. The third stage of thermal degradation occurred in the temperature range of 356 Ce600 C, with a loss in weight of 31.69% due to degradation of lignin as well as original structure also gets destroyed. After this temperature, no further decomposition takes place. From DTG curve, it is evident that dehydration happens below 120 C, de-volatilisation takes place from 120 to 380 C & decomposition happens from 380 to 600 C. The result of TGA and DTG curve shows that 350e550 C temperature range would be optimal for pyrolysis zone. The yield of char at different pyrolysis temperature is quite similar to the results obtain from TGA, which is shown in Table 2. The higher char yield was due to the presence of higher inorganic material, which can be characterised as ash. 3.3. Influence of temperature on pyrolysis product yields To verify the effect of temperature on the yield of pyrolysis product, several experiments were conducted at various temperature intervals, ranging from 350, 375, 400, 425, 450, 475, 500, 525 & 550 C at a constant heating rate of 25 C/min with a sweeping N2 gas flow rate of 0.1 L/min. From Table 3 and Fig. 3, it can be concluded that, with the rise in temperature from 350 C to 450 C, the yield of oil (32.13e40.1 wt.%) and yield of gas increased (12.71e23.14 wt.%) while decrease in bio-char yield (50.56e34.21 wt.%). The decrease in char percentage was due to the secondary decomposition and loss of volatile matter at higher pyrolysis temperature [24,25]. Increase in temperature caused higher gas yield and lower oil yield, which was due to the secondary cracking of pyrolysis vapour at higher pyrolysis temperature [26]. Since the pyrolysis process is fast, the vapour residence time (Table 3), decreased with increase in temperature. Since, shorter vapour residence time in heated zone yielded high bio-oil percentage over char. The loss percentage was >10% up-to 450 C and further rise in temperature from 450 C to 550 C caused higher loss percentage. From the above analysis, it can be concluded that the optimum temperature for oil production is 450 C in case of A. philoxeroides in the present experimental conditions. After subjecting the experimental data in one-way ANOVA (origin 8), the obtained P is significant at 0.05 level using Tukey model. The p values indicate that the variation in yield (liquid, char, & gas) due to change in temperature from 350 C to 550 C are statistically significant. The composition of Syn-gas obtained as a result of pyrolysis with fixed N2 gas flow rate & heating rate (25 C/min) is also illustrated in Table 3. The major gaseous product of A. philoxeroides pyrolysis are H2, CO2, CO, CH4, C2H6 and C3H8. Out of these six major gases, percentage of CO2 was more, which later decreased with rise in pyrolysis temperature. The concentration of CH4 increased with rise in temperature. The percentage of H2 also increased at elevated temperature of pyrolysis due to severe cracking of all the condensable and non-condensable products. The reaction between CO2 and carbon in char also lead to the increase of CO percentage at higher pyrolysis temperature, due to reverse Boudouard reaction [27e29]. Reverse Boudouard reaction is mainly responsible for CO2 depletion.
Fig. 2. TGA and DTG of Alternanthera philoxeroides biomass powder.
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
7
Table 2 Comparison of char obtained from TGA and pyrolysis. Temperature C
TGA (wt.%)
Pyrolysis Char (wt.%)
350 375 400 425 450 475 500 525
54.103 40.94 37.58 35.26 33.19 30.59 27.75 25.16
50.56 45.05 39.67 36.01 34.21 31.27 28.61 26.57
Table 3 Influence of different pyrolysis temperature on product yields at constant heating rate of 25 C/min & 0.1 L/min (N2 gas) flow rate. Characteristics
Temperature C
350
375
400
425
450
475
500
525
550
Muffle furnace Yield wt.%
Time taken to reach@ 25 C/min (Heating rate) Total Liquid Organics Water Char Gas Loss Closure (%) Reaction time N2 gas Syn-gas Time (s) Gas selectivity H2 CO2 CO CH4 C2H6 C3H8 g/mol
14 32.13 10.72 21.40 50.56 12.71 4.60 95.4 48 0.1 0.048 2.03 mol% 4.352 71.28 18.04 4.53 0.68 1.37 121.6
15 33.96 13.73 20.43 45.05 13.74 7.25 92.75 46 0.1 0.057 1.94 mol% 4.596 69.93 18.59 4.67 0.78 1.48 80.43
16 35.32 15.91 19.41 39.67 15.77 9.24 90.76 44 0.1 0.064 1.48 mol% 4.74 68.17 18.48 4.88 0.84 2.59 68.39
17 38.14 18.27 19.27 36.01 16.38 9.47 90.53 41 0.1 0.071 1.33 mol% 4.78 69.25 18.63 4.49 0.56 2.29 55.57
18 40.10 19.99 20.11 34.21 16.48 9.21 90.79 37 0.1 0.08 1.06 mol% 5.03 67.16 19.45 4.93 0.65 2.78 43.77
19 38.77 18.56 20.21 31.27 17.98 11.98 88.02 33 0.1 0.093 0.91 mol% 5.09 68.13 19.51 5.04 0.88 1.35 32.37
20 36.42 17.16 19.26 28.61 19.81 15.16 84.84 29 0.1 0.13 0.85 mol% 8.44 61.27 20.52 6.63 0.93 2.21 20.82
21 34.74 14.71 20.03 26.57 21.58 17.11 82.59 24 0.1 0.178 0.79 mol% 9.73 57.39 22.19 6.78 0.97 2.94 8.84
22 31.93 13.80 18.13 23.70 23.14 21.23 78.77 19 0.1 0.251 0.72 mol% 15.04 55.45 19.77 6.93 0.68 2.13 4.45
Time (min) Flow rate L/min Flow rate L/min Vapour residence time Sys-gas composition analysis
Molecular weight
3.4. Influence of sweeping gas flow rate on pyrolysis product yields Nitrogen flow has an impact on the residence time of vapour phase and restrains the secondary cracking reactions at vapour phase [30]. To determine the influence of the sweeping gas flow rate, experiments was carried out under varying nitrogen flow rates of 0.1, 0.2, 0.3, 0.4, & 0.5 L/min at a fixed pyrolysis temperature of 450 C, with a constant heating rate of 25 C/min. The effect of sweeping gas flow on pyrolysis product yield is represented in Table 4 and Fig. 4. The maximum oil yield was 42.28% with a sweeping gas flow rate of 0.2 L/min. Short vapour residence time (0.98 s) of pyrolysis vapours in the reactor was due to the high flow rates of sweeping N2 gas. The maximum yield of bio-oil can only be accomplished with short vapour
Fig. 3. Influence of different pyrolysis temperature on product yields at constant heating rate of 25 C/min & 0.1 L/min (N2) flow rate.
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
8
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
Table 4 Influence of sweeping gas flow rate on pyrolysis product yields at fixed pyrolysis temperature @ 450 C. Characteristics
Temperature C
450
450
450
450
450
Muffle furnace Yield wt.%
Time taken to reach 450 C @ 25 C/min (Heating rate) Total Liquid Organics Water Char Gas Loss Closure (%) Reaction time N2 gas Syn-gas Time (s) Gas selectivity H2 CO2 CO CH4 C2H6 C3H8 g/mol
18 40.10 19.99 20.11 34.21 16.48 9.21 90.79 37 0.1 0.08 1.06 mol% 5.03 67.16 19.45 4.93 0.65 2.78 43.77
18 42.28 23.17 19.11 30.33 20.54 6.85 93.15 35 0.2 0.106 0.98 mol% 5.28 66.89 19.83 5.16 0.78 2.06 99.72
18 38.48 19.27 19.21 28.37 21.46 11.29 88.31 31 0.3 0.125 0.95 mol% 5.13 66.38 19.88 5.23 0.81 2.57 161.35
18 36.25 16.22 20.03 27.01 23.77 12.97 87.03 29 0.4 0.148 0.93 mol% 5.13 66.36 19.92 5.19 0.88 2.52 204.52
18 33.96 15.17 18.78 26.23 23.89 15.92 84.07 26 0.5 0.166 0.89 mol% 5.17 66.28 19.80 5.21 0.93 2.61 254.15
Time (min) Flow rate L/min Flow rate L/min Vapour residence time Sys-gas composition analysis
Molecular weight
Fig. 4. Influence of sweeping gas flow rate on pyrolysis product yields at fixed pyrolysis temperature @ 450 C.
residence time of pyrolysis vapours and lower char yield. From Table 4, it was evident the vapour residence time reduced with increase in the flow rate of N2 gas. The yield of pyrolysed oil at 0.2 L/min was more compared to 0.3, 0.4 and 0.5 L/min. Moreover, increasing inert gas flow rate from 0.1 to 0.5 L/min caused higher percentage of volatile matter production. Since, fast flow rate stops the ideal quenching of thermally cracked pyrolysis vapours. As a result, chemical reactions stops before the valuable initial reaction products can be degraded [31,32]. It can be concluded from the experiment that 0.2 L/min is the best sweeping gas flow for pyrolysed oil production at 450 C. After subjecting the experimental data in one-way ANOVA (origin 8), it showed Sig 1 (significance ¼ 1), which indicated that the means difference is significant at the 0.05 level. The p (<0.005) values indicate that the variation in yield (liquid, char, & gas) due to variation in N2 gas flow rate from 0.1 to 0.5 L/min is statistically significant. The composition of pyrolysis gas as a function of N2 flow rate is shown in Table 4. The major gaseous product are same as obtained in Table 3. There is no significant change in the percent composition of gaseous product in case of different flow rate of N2. CO2 was the major component among the present gases accounting to about 60e70%. However, the molecular weight of gas increased from 43.77 g/mol to 254.15 g/mol when the flow rate was increased from 0.1 to 0.5 L/min. 3.5. Influence of heating rate on pyrolysis product yield The third group of experiments was conducted to determine the effect of heating rate on the pyrolysis yields. These experiments were conducted with four different heating rates of 25, 50, 75 & 100 C/min at a fixed pyrolysis temperature of 450 C and were swept with a gas flow rate of 0.2 L/min. In fast pyrolysis the liquid product yield is higher since the fast heating rates allow the conversion of thermally unstable biomass compounds to a liquid product due reduced heat and mass transfer limitations, before they form undesired coke [2,33]. Experimental results are given in Table 5 and Fig. 5. Secondary reactions will occur due to increase in residence time in pyrolysis. Higher liquid products are produced in fast pyrolysis compared to slow pyrolysis. Increase in heating rate from 25 C/min to 50 C/min resulted in an increase of bio-oil yield from 42.28% to 43.15%, later decreased to 37.13% when increased from 75 C/min to 100 C/min. With the rise in heating rate from 25 to 100 C/min, the yield of char decreased from 30.33% to 24.67% and yield of gas increased from 20.54% to 21.03%. From Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
9
Table 5 Influence of heating rate on pyrolysis product yield at fixed N2 flow rate and 450 C. Heating rate
Muffle furnace Temperature Yield wt.%
Time taken to reach 450 C C Total liquid Organics Water Char Gas Loss Closure (%) Reaction time N2 gas Syn-gas Time (seconds) Gas Selectivity H2 CO2 CO CH4 C2H6 C3H8 g/mol
Time (min) Flow rate L/min Flow rate L/min Vapour Residence Time Sys-gas composition analysis
Molecular weight
C/min
25
50
75
100
18 450 42.28 23.17 19.11 30.33 20.54 6.85 93.5 35 0.2 0.106 0.98 mol% 5.28 66.89 19.83 5.16 0.78 2.06 99.72
9 450 43.15 24.66 18.49 28.74 21.09 7.02 92.98 34 0.2 0.113 0.92 mol% 5.33 66.11 19.86 5.19 0.81 2.10 87.75
6 450 40.02 22.15 18.07 26.28 21.02 12.68 87.52 32 0.2 0.119 0.82 mol% 5.44 65.84 19.89 5.17 0.85 2.83 79.13
4.5 450 37.13 19.45 17.68 24.67 21.03 17.17 82.83 31 0.2 0.123 0.78 mol% 5.45 65.53 19.87 5.22 0.94 2.99 74.06
Fig. 5. Influence of heating rate on pyrolysis product yield at fixed N2 gas flow rate and 450 C temperature.
the experiment, it is clear that at higher heating rates the yield of char decreases compared to lower heating rates, due to faster depolymerization of solid biomass to primary volatiles [34]. Therefore, from the experiment it can be concluded that the optimum yield of bio-oil is possible at a pyrolysis temperature of 450 C, at a heating rate of 50 C/min with a sweeping gas flow rate of 0.2 L/min. The statistical analysis of the data from Table 5, regarding variation of heating rate on pyrolysis product yield, indicate that the variation of heating rate on pyrolysis yield at constant temperature (450 C) and N2 gas (0.2 L/min) flow rate is not significant, since the value of P is above 0.05. However, the value of p was <0.05, in case of char, gas and loss respect to heating rate, which indicated that the mean difference is significant at 0.05 level. The composition of pyrolysis gas as a function of different heating rate is shown in Table 5. The major gaseous product is same as obtained in Tables 3 and 4. There is no significant change in the percent composition of gaseous product in case of different heating rates. CO2 was the major component among the present gases accounting to about <70% >60%. However, the molecular weight of gas decreased from 99.72 g/ mol to 74.06 g/mol when the heating rate was increased from 25 C/min to 100 C/min. 3.6. Characterization of bio-oil The physical and chemical characteristic of bio-oil is represented in Table 6. The potentiality of bio-oil to be used as a fuel depends on its heating value. The HHV of A. philoxeroides weed bio-oil was found to be 8.88 MJ/kg, which was little more than the result obtained by WuJun Liu et al. [10]. The elemental values in Table 1, are lower compare to raw material, so its energy density will also be less. Since, biomass derived fuel contains higher oxygen content compared to fossil fuel, therefore its heating value and energy density will be inferior compare to commercial fuels such as diesel and petrol and will also lead to ignition delay [35]. The average chemical composition of bio-oil was found to be CH4.20 N0.06 O2.10 P0.0024. The H/C ratio of bio-oil is somewhat closer to methane. The water content in bio-oil was found to 18.49 wt.% Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
10
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14 Table 6 Physical properties of bio-oil obtained at 450 C. Properties
Bio-oil
Carbon Hydrogen Nitrogen Phosphorous* Oxygen H/C O/C N/C P/C Empirical formula Viscosity @ 100 C Density Flash point Fire point Appearance Odour Miscibility Initial boiling point Final boiling point
23.61 8.27 1.74 0.07 66.31 4.20 2.10 0.06 0.0024 CH4.20 N0.06 O2.10 P0.0024 4.12 cSt 0.9473 kg/m3 52 C 67 C Dark brown Smoky CH4, CHCl3, CH2Cl2, etc 94 370
*
EDX analysis.
(450 C, 0.2 L/min at 50 C/min) of the pyrolysis bio-oil, due to high oxygen content of biomass structure consisting mainly of cellulose, hemicellulose and lignin [36]. The bio-oil has lower ash content, which means that it can use as clean fuel oil. The pH of the bio-oil was found to be 6.26, which is lower due the presence of organic acid. The acid number of the bio-oil was found to be 41.26 mg KOH g1. In comparison to conventional transportation fuel (Table 7) the viscosity and density of the A. philoxeroides bio-oil was found to be more. Higher viscosity and density may lead to poor flow characteristics, stability and will cause high-pressure drops in pipelines leading to higher pumping costs and atomization in engine [37]. Higher density and viscosity of the bio-oil can be modified by blending with different commercial fuel or by upgrading with help of catalyst addition. The initial boiling point of the pyrolysis oil was 94 C, which means that the liquid contains considerable amount of volatile matter. The pyrolysis oil consists of wide verity of chemicals, which can be identified by determining the organic groups by FT-IR analysis represented in Fig. 6. Broad and strong absorbance spectra of A. philoxeroides was observed at 3220.76 cm1 indicates the presence of Table 7 Comparison of fuel properties of Alternanthera philoxeroides weeds bio-oil with conventional transportation fuels. Properties fuels
Specific gravity 15/15 C
Kinematic viscosity @ 40 C
Flash point ( C)
Fire point ( C)
HHV (MJ/kg)
Initial boiling point ( C)
Final boiling point ( C)
Alternanthera philoxeroides weed bio-oil Gasoline [41] Diesel [41]
0.9486
24.67
52
67
8.88
94
370
0.72e0.78 0.82e0.85
0.400e0.550 [39] 2e5.5
43 53e80
53 to 60 [38] 65e95 [40]
42e46 42e45
27 172
225 350
Fig. 6. FT-IR of bio-oil obtained at 450 C.
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
11
alcohols and phenols. The CeH stretching vibration at 2956.43, 2923.33 cm1 and 2853.06 cm1 indicates the presence of methylene group. The PeH sharp vibration at 2361.60 cm1 and 2341.12 cm1 indicates the presence of phosphine. The presence of carboxyl group of aldehyde and ketone can be seen at a vibration of 1704.62 cm1. The C]C stretching vibration at 1659.92 cm1, 1608.67 cm1, 1559.34 cm1, 1556.62 cm1, & 1514.91 cm1 indicated the presence of alkenes and aromatics compounds. The N]O asymmetric stretch vibration at 1514.31 cm1 indicated the presence of nitro groups. The presence of nitro group in bio-oil will lead to the formation of aliphatic nitrogenous compounds. The CeH deformation at 1455.92 cm1 indicated the presence of alkanes. The CeO vibration at 1377.61 cm1 indicates the presence of carboxylic acids. The AreN stretching vibration at 1326.51 indicated the presence of amines. The CeO stretching vibration at 1272.29, 1242.21 cm1 & 1221.03 cm1, indicates the presence of ethers. The OeH bending and C]C stretching from 975 to 525 cm1 indicates the presence of mono, polycyclic, substituted aromatics rings in bio-oil. Out of many compounds present in bio-oil only 26 compounds are enlisted in Table 8. The various organic products present in the bio-oil (Fig. 7) were Alcohol, Aldehyde, Amine, Ketone, Alkenes & Alkanes. The bio-oil from A. philoxeroides contains 20.59% of phenols, 11.07% amines, 14.59% aldehydes, 15.07% ketones, 16.44% alkenes, and 15.22% alkanes. The higher percentage of phenols in the bio-oil is due to the decomposition of lignin and impurities present in water [42,43]. The main phenolic compounds present in bio-oil are phenols, 2-methoxy-
Table 8 GCeMS of bio-oil at 450 C. Retention time (min)
Compound
Area %
Classification
Formula
4.52 4.79 4.86 5.96 6.25 7.37 8.83 9.07 9.27 10.05 11.32 11.37 12.32 14.37 14.51 16.99 17.03 18.72 18.76 19.09 20.66 21.78 22.136 23.80 24.08 25.60 26.32
Phenol Acetic acid Ethylene-di-amine Benzylamine 2-methoxy-phenol 2,4,5-Trimethoxy-benzaldehyde 3-Methyl-1,2-cyclopentanedione 1-methyl-2-nitro-benzene Pyrocatechol 2-ethenyl-naphthalene 5-Methylfuran-2-carbaldehyde Cyclopent-2-enone 2-Furylcarboxaldehyde 2,4,6-Trimethoxyacetophenone 1,3,5-trimethyl-benzene 2,4,4-Trimethyl-2-pentylamine Isothiocyanato-Methane Tridecane 1-Hydroxy-2-propanone 2,6-dimethyl-phenol Triphenyl-silanol 2,4-di-tert-butyl-phenol Tetracosane Resorcinol 2,3,6-trimethylnaphalene 4,5-Dimethyl-4,5-dihydro-1H-pyrazole 3,4,5-trimethoxy-a-methyl-phenethylamine
5.15 2.54 1.84 5.43 4.51 3.53 2.89 4.19 2.14 5.79 3.82 2.73 6.14 2.22 3.15 1.74 2.01 4.58 7.23 2.17 2.53 4.18 3.45 2.05 3.31 1.10 2.06
Alcohol Carboxylic acid Amine Amine Alcohol Aldehyde Ketone Alkene Alcohol Alkene Aldehyde Ketone Aldehyde Ketone Alkene Amine Alkane Alkane Ketone Alcohol Alcohol Alcohol Alkane Alcohol Alkene Aldehyde Amine
C6H6O C2H4O2 C2H8N2 C7H9N C7H8O2 C10H12O4 C6H8O2 C7H7NO2 C6H6O2 C12H10 C6H6O3 C5H6O C5H4O2 C11H14O4 C9H12 C8H19N C2H3NS C13H28 C3H6O2 C9H12 C18H16OSi C14H22O C24H50 C6H6O2 C13H14 C8H10N2 C12H19NO3
Fig. 7. GCeMS of bio-oil at 450 C.
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
12
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
Phenol, 2, 6-dimethyl-Phenol, and 2,4-di-tert-Butyl-Phenol. Acid present in bio-oil will lead to corrosion. If acids can be separated from biooil, they have the potential to be used as a chemical feedstock. The presence of oxygenated compounds in bio-oil will have a negative effect in the heating value of bio-oil. In order to utilize bio-oil effectively for energy generation, proper separation of oxygenated compounds is necessary. The presence of nitrogenous compounds in bio-oil is due to the conversion of amino acids into amines. The carbon chain length in bio-oil ranges from C2eC24, which is similar to conventional transportation fuel. 3.7. Characterization of bio-char The carbon content and calorific value of bio-char was found to be more in comparison to biomass and bio-oil, which supplements its usage as activated carbon and solid fuel. Increase in fixed carbon content is due to low volatile matter content in bio-char, so less liberation of fixed carbon. The elemental analysis of bio-char showed significant decrease in oxygen and slight variation in hydrogen, nitrogen and phosphorous content. Lower oxygen content helps to increase in the percentage of carbon content in A. philoxeroides sample during pyrolysis. The proximate and ultimate analysis of bio-char is represented in Table 9. The functional group characterization of bio-char obtained at 450 C is shown in Fig. 8. Broad and strong absorbance spectra of A. philoxeroides was observed in the region between 3600 and 3400 cm1 indicating the presence of carbohydrates and proteins. With increase in temperature, the spectrum reduced, due to conversion of carbohydrates and protein during the reaction. Strong CeH stretching (methyl and methylene groups) absorbance spectra can be seen in bio-oil, where as weak aliphatic CeH stretching can be seen in case of bio-char due to heat resistance RCH2CH3 structures [44]. The vibration at 1568.49 and 1557.64 cm1 indicates the presence of aromatic rings. The OeH bending and C]C stretching from 975 to 525 cm1 indicates the presence of mono, polycyclic, substituted aromatics rings in bio-char. At elevated temperature most of the functional groups will vanished and only char will remain in the form of aromatic polymer carbon atom [45]. Chemicals adsorption, reactivity and combustion property depends on the surface area of bio-char. The surface area of the biomass was found to be 36.5 m2/g and the surface area of the bio-char increased to 123.71 m2/g after pyrolysis at 450 C. Due to high surface area compare to its biomass, the char could be used for adsorption. However, with increase in temperature of pyrolysis up-to 550 C the surface area of bio-char increased to 375.2 m2/g. The surface area of bio-char increased with rise in temperature due release of volatile matter resulting from secondary decomposition. The SEM images of biomass and bio-char at 5KX magnification at an acceleration voltage of 15 KV are given in Fig. 9. The comparison of both the SEM images of biomass and bio-char highlights the morphological changes happening after devolatization steps. The release of Table 9 Proximate and ultimate analysis of bio-char obtained at 450 C. Properties
Bio-char
Moisture, wt.% Volatile matter wt.% Ash content wt.% Fixed carbon content wt.% Carbon Hydrogen Nitrogen Oxygen Phosphorous H/C O/C N/C P/C HHV (MJ/kg) Empirical formula
0.63 16.68 31.84 50.85 52.39 3.66 4.29 39.11 0.55 0.84 0.56 0.07 0.0084 20.41 CH0.84 N0.07 O0.56 P0.0084
Fig 8. FT-IR of bio-char at 450 C.
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
13
Fig 9. SEM images of (a) biomass and, (b, c) bio-char obtained at 450 C and 550 C.
volatile matter at elevated temperature leads to formation of rough textures on the surface and heterogeneous distribution of pores in biochar. The increase in pores size and surface is due to the fast thermal decomposition of lignin at elevated temperatures. The average pore diameter at 450 C was 4.83 mm and later increased to 11.64 mm at 550 C. The increase in the pore diameter with rise in temperature was due to the coalescence of smaller pores, which leads to large internal cavities and more open structures [45e47]. 4. Conclusion In this study, A. philoxeroides biomass was found to be feasible for bio-oil production from pyrolysis. ❖ The maximum liquid yield was found to be 40.10% at a sweeping gas flow rate of 0.1 L/min at 450 C, at a constant heating rate of 25 C/min. ❖ However, with varying sweeping gas flow rate from 0.1 to 0.5 L/min, the yield of bio-oil increased to 42.28% only at a sweeping gas flow rate of 0.2 L/min at a constant heating rate of 25 C/min. ❖ With varying heating rate, the yield of bio-oil increased to 43.15% at a heating rate of 50 C/min. ❖ Loss percentage can be minimised by the use of chillers, cryogenic medium, etc. ❖ The percentage of phenol and oxygenated compounds were more in bio-oil analysed by GCeMS and FT-IR. ❖ The carbon chain length in bio-oil lied from C2eC24 and its empirical formula was found to be CH4.20N0.06O2.10P0.0024. ❖ The bio-char attained during pyrolysis had a higher calorific value of 20.41 MJ/kg compare to biomass and bio-oil. The surface area and pore size of bio-char increased from 4.83 mm, 123.71 m2/g to 11.64 mm, 375.2 m2/g with rise in temperature. ❖ From the analysis, it can be concluded that the obtained bio-oil can be utilized as a fuel by upgrading or blending with other fuels. The bio-char has the potential to be utilised as a solid fuel. References [1] A.H. Gerhauser, A.V. Bridgwater, Production of renewable phenolic resins by thermochemical conversion of biomass, Renew. Sust. Energy Rev. 12 (2008) 2092e2116. € [2] Bas¸ak Burcu Uzun, Esin Apaydin-Varol, Funda Ates¸, Nurgül Ozbay, Ays¸e Eren Pütün, Synthetic fuel production from tea waste: characterisation of bio-oil and bio-char, Fuel 89 (2010) 176e184. [3] G. van Rossum, S.R.A. Kersten, W.P.M. van swaaij, Ind. Chem. Res. 46 (2007) 3959. [4] S. Yorgun, S. Sensoz, O.M. Kockar, Characterization of the pyrolysis oil produced in the slow pyrolysis of sunflower-extracted bagasse, Biomass Bio-energy 20 (2001) 141e148. [5] S. Vitolo, M. Seggiani, P. Frediani, G. Ambrosini, L. Politi, Catalytic upgrading of pyrolytic oils to fuel over different zeolites, Fuel 78 (1999) 1147e1159. [6] S. Zhang, Y. Yan, T. Li, Z. Ren, Upgrading of liquid fuel from the pyrolysis of biomass, Bioresour. Technol. 96 (2005) 545e550. [7] A.V. Bridgwater, Biomass pyrolysis technologies, in: G. Grassi, G. Gosse, G. Dos Santos (Eds.), Biomass Energy Ind. Environ. 5th E.C. Conference, Elsevier, London, New York, 1990, pp. 2489e2496. [8] C. Di Blasi, Modeling chemical and physical processes of wood and biomass pyrolysis, Prog. Energy Combust. 34 (2008) 47e90. lu, E. Tetik, E. Gollu, Biofuel production using slow pyrolysis of the straw and stalk of rapeseed plant, Fuel Process. Technol. 59 (1999) 1e12. [9] F. Karaosmanog [10] Wu-Jun Liu, Fan-Xin Zeng, Hong Jiang, Hang-Qing Yu, Total recovery of nitrogen and phosphorus from three wetland plants by fast pyrolysis technology, Bioresour. Technol. 102 (3) (November 2011) 3471e3479. [11] Kittiphop Promdee, Tharapong Vitidsant, Supot Vanpetch, Comparative study of some physical and chemical properties of bio-oil from Manila grass and water hyacinth transformed by pyrolysis process, Int. J. Chem. Eng. Appl. 3 (1) (February 2012). [12] Nazim Muradov, Beatriz Fidalgo, Amit C. Gujar, Ali T-Raissi, Pyrolysis of fast-growing aquatic biomass e Lemna minor (duckweed): characterization of pyrolysis products, Bioresour. Technol. 101 (2010) 8424e8428. [13] Seung-Soo Kim, Foster A. Agblevor, Thermogravimetric analysis and fast pyrolysis of Milkweed, Bioresour. Technol. 169 (2014) 367e373. [14] J.K. Maheshwari, Alligator weed in Indian lakes, Letter to nature, Nat. 206 (19 June 1965) 1270. [15] Ankit Agrawalla, Sachin Kumar, R.K. Singh, Pyrolysis of groundnut de-oiled cake and characterization of the liquid product, Bioresour. Technol. 102 (22) (November 2011) 10711e10716. [16] Beena Patel, Bharat Gami, Biomass characterization and its use as solid fuel for combustion, Iran. J. Energy Environ. 3 (2) (2012) 123e128. [17] Haiping Yang, Rong Yan, Hanping Chen, Dong Ho Lee, Chuguang Zheng, Characteristics of hemicellulose, cellulose and lignin pyrolysis, Fuel 86 (2007) 1781e1788. [18] A. Friedl, E. Padouvas, H. Rotter, K. Varmuza, Prediction of heating values of biomass fuel from elemental composition, Anal. Chim. Acta 544 (1e2) (15 July 2005) 191e198. [19] T. Cornelissen, M. Jans, J. Yperman, G. Reggers, S. Schreurs, R. Carleer, Flash co-pyrolysis of biomass with polyhydroxybutyrate: Part 1. Influence onbio-oil yield, water content, heating value and the production of chemicals, Fuel 87 (2008) 2523e2532.
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011
14
N. Bhattacharjee, A.B. Biswas / Journal of the Energy Institute xxx (2017) 1e14
[20] Rahul Singh Chutia, Rupam Kataki, Thallada Bhaskar, Characterization of liquid and solid product from pyrolysis of Pongamiaglabradeoiled cake, Bioresour. Technol. 165 (2014) 336e342. [21] Tanmya Rout, Debalaxshmi Pradhan, R.K. Singh, Namrata Kumari, Exhaustive study of products obtained from coconut shell pyrolysis, J. Environ. Chem. Eng. 4 (3) (September 2016) 3696e3705. [22] Haibo Xie, Nicholas Gathergood, The Role of Green Chemistry in Biomass Processing and Conversion, 2012, pp. 45e46. [23] N.K. Nayan, S. Kumar, R.K. Singh, Production of the liquid fuel by thermal pyrolysis of neem seed, Fuel 103 (2013) 437e443. [24] O. Onay, O. Mete Kockar, Fixed-bed pyrolysis of rapeseed (Brassica napus L.), Biomass Bioenergy 26 (3) (2004) 289e299. [25] P. Kim, A. Johnson, C.W. Edmunds, M. Radosevich, F. Vogt, T.G. Rials, N. Labbe, Surface functionality and carbon structures in lignocellulosic-derivedbiochars produced by fast pyrolysis, Energy Fuels 25 (10) (2011) 4693e4703. [26] J.M. Encinar, J.F. Gonzalez, J. Gonzalez, Fixed-bed pyrolysis of Cynaracardunculus L. product yields and compositions, Fuel Process. Technol. 68 (3) (2000) 209e222. €l Becidan, Øyvind Skreiberg, Johan E. Hustad, Products distribution and gas release in pyrolysis of thermally thick biomass residues samples, J. Anal. Appl. [27] Michae Pyrolysis 78 (1) (January 2007) 207e213. ndez, A. Domínguez, Y. Ferna ndez, J.J. Pis, Evidence of self-gasification during the microwave-induced pyrolysis of coffee hulls, Energy Fuels 21 (1) (2007) [28] J.A. Mene 373e378. [29] Haiping Yanga, Rong Yanb, Hanping Chena, Dong Ho Leeb, David Tee Liang, Chuguang Zhenga, Pyrolysis of palm oil wastes for enhanced production of hydrogen rich gases, Fuel Process. Technol. 87 (10) (October 2006) 935e942. [30] B.B. Uzun, A.E. Putun, E. Putun, Composition of products obtained via fast pyrolysis of olive-oil residue: effect of pyrolysis temperature, J. Anal. Appl. Pyrolysis 79 (2007) 147e153. [31] A.E. Putun, N. Ozbay, E. Apaydin-Varol, B.B. Uzun, F. Ates, Rapid and slow pyrolysis of pistachio shell: effect of pyrolysis conditions on the product yields and characterization of the liquid product, Int. J. Energy Res. 31 (2007) 506e514. [32] R. Maggi, B. Delmon, Comparison between slow and flash-pyrolysis oils from biomass, Fuel 73 (1994) 671e677. [33] Lecture-10, Principles of Pyrolysis. http://eagri.tnau.ac.in/eagri50/AENG352/lec10.pdf. [34] G. Chen, Q. Yu, K. Sjostrom, Reactivity of char from pyrolysis of birch wood, J. Anal. Appl. Pyrolysis 40e41 (1997) 491e499. [35] Lu. Qjang, Wenzhi Li, Xifeng Zhu, Overview of applications of biomass fast pyrolysis oil, Energy Convers. Manag. 50 (2009) 1376e1383. [36] N. Worasuwannarak, T. Sonobe, W. Tanthapanichakoon, Pyrolysis behaviours of rice straw, rice husk and corncob by TG-MS technique, J. Anal. Appl. Pyrolysis 78 (2007) 265e271. [37] www.ilpi.com/msds/ref/flashpoint.html. [38] www.engineersedge.com/fluid_flow/kimematic-viscousity-table.htm. [39] Vikranth Volli, R.K. Singh, Production of bio-oil from de-oiled cakes by thermal pyrolysis, Fuel 96 (2012) 579e585. [40] T. Siengchum, M. Isenberg, S.S.C. Chuang, Fast pyrolysis of coconut biomassdan FTIR study, Fuel 105 (2013) 559e565. [41] Petroleum Product Surveys, Motor Gasoline, Summer, Winter 1986/1987, National Institute for Petroleum and Energy Research, 1986. http://www.afdc.energy.gov/afdc/ pdfs/fueltable.pdf. [42] B. Hasanah, The chemical composition and physical properties of the light and heavy tar resulted from coconut shell pyrolysis, J. Pure Appl. Chem. Res. 1 (2012) 26e32. [43] B. Sukhbaatar, P.H. Steele, L.L. Ingram, M.G. Kim, An exploratory study on the removal of acetic and formic acids from bio-oil, BioResources 4 (2009) 1319e1329. [44] Peigao Duan, Zhoufan Chang, Yuping Xu, Xiujun Bai, Feng Wang, Lei Zhang, Hydrothermal processing of duckweed: effect of reaction conditions on product distribution and composition, Bioresour. Technol. 135 (2013) 710e719. [45] V. Gomez-Serrano, P.M. Alvarez, J. Jaramillo, F.J. Beltran, Formation of oxygen complexes by ozonation of carbonaceous materials prepared from cherry stones, I, Therm. Eff. Carbon 40 (2002) 513e522. [46] M. Guerrero, M.P. Ruiz, M.U. Alzueta, R. Bilbao, A. Millera, Pyrolysis of eucalyptus at different heating rates: studies of char characterization and oxidative reactivity, J. Anal. Appl. Pyrolysis 74 (2005) 307e314. [47] E. Apaydin-Varol, E. Putun, A.E. Putun, Slow pyrolysis of pistachio shell, Fuel 86 (2007) 1892e1899.
Please cite this article in press as: N. Bhattacharjee, A.B. Biswas, Pyrolysis of Alternanthera philoxeroides (alligator weed): Effect of pyrolysis parameter on product yield and characterization of liquid product and bio char, Journal of the Energy Institute (2017), http://dx.doi.org/10.1016/ j.joei.2017.02.011