Fast pyrolysis of contaminated sawdust in a circulating fluidised bed reactor

Accepted Manuscript Title: Fast Pyrolysis of Contaminated Sawdust in a Circulating Fluidised Bed Reactor Author: Keyoon Duanguppama Nuchida Suwapaet Adisak Pattiya PII: DOI: Reference:

S0165-2370(15)30448-4 http://dx.doi.org/doi:10.1016/j.jaap.2015.12.025 JAAP 3644

To appear in:

J. Anal. Appl. Pyrolysis

Received date: Revised date: Accepted date:

11-7-2015 14-12-2015 31-12-2015

Please cite this article as: Keyoon Duanguppama, Nuchida Suwapaet, Adisak Pattiya, Fast Pyrolysis of Contaminated Sawdust in a Circulating Fluidised Bed Reactor, Journal of Analytical and Applied Pyrolysis http://dx.doi.org/10.1016/j.jaap.2015.12.025 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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Fast Pyrolysis of Contaminated Sawdust in a Circulating Fluidised Bed Reactor Keyoon Duanguppama, Nuchida Suwapaet, Adisak Pattiya* [email protected] Bio-Energy and Renewable Resources Research Unit, Faculty of Engineering, Mahasarakham University, Kamriang, Kantharawichai, Maha Sarakham 44150, Thailand *

Corresponding author: Tel.: +664 375 4321x 3036; fax: +664 375 4316.

2 Highlights - Contaminated sawdust gave 67wt% bio-oil yield with 30 MJ/kg LHV. - Effects of solid and liquid contaminants on pyrolysis products are discussed. - Mineral oil contaminants led to bio-oil yield increase. - Bio-oil contained large proportion of hydrocarbons. - Contaminants increased bio-oil viscosity and LHV and decreased char LHV.

3 Abstract Sawdust contaminated with mineral oils and solids was pyrolysed in a circulating fluidised bed (CFB) reactor. The objectives are to investigate the influences of pyrolysis temperature (400-600°C) and the contaminants on product yields and properties. The results show that bio-oil reached its maximum yield of 67 wt% at 500°C and had a lower heating value (LHV) of ~30 MJ/kg. At this temperature, the char yield of 18 wt% with an LHV of 18 MJ/kg and the gas yield of 15 wt% with an LHV of 28 MJ/Nm3 were obtained. Increasing the temperature tended to reduce the bio-oil water content and stability, while increasing its LHV and viscosity. The presence of mineral oils increased the organic bio-oil yield by suppressing the reaction water and increased the heating value of the non-condensable gas by nearly 3fold. Both solid and liquid contaminants increased the bio-oil viscosity and LHV and decreased the char LHV. In addition, GC/MS analysis of bio-oils from contaminated sawdust showed the presence of C12-C44 hydrocarbon components. Keywords: Bio-oil; Circulating fluidised-bed; Contaminated Sawdust; Fast pyrolysis

4 1. Introduction Sawdust as a residue from wood-processing industries, such as saw mill and furniture factories, can be utilised for particle board manufacture, char coal production, mushroom cultivation and heat generation. In a more advanced note, the sawdust could be used as raw material in gasification for the production of synthesis gas [1] and fast pyrolysis for the production of bio-oil [2]. Pietrzak has shown that sawdust pellets can be used as adsorbents for NO2 removal [3]. Some applications of sawdust generate wastes which may be contaminated with inorganic matter. One of the most interesting applications is the use of sawdust for oil spill adsorption in metal-working factories and automobile service garages. Although this application is not worldwide and in some contries such as USA, Japan and Germany, the car producers try to avoid any solid material to collect oil residues but rather try to clean the parts with only air or assisted with some little amounts of liquids, in some developing countries like Thailand, the use of sawdust or other solid material for oil spill cleaning is existing due to low cost. The oils spilled include engine oil, gear oil, machine oil gasoline and diesel. The sawdust is contaminated with these mineral oils and some metal particles as well as some soil or dust. In Thailand alone, it is estimated that more than 12,000 ton per year of this type of contaminated sawdust (CS) is generated [4]. This CS is regarded as a hazardous waste. Proper management of this waste could be expensive. This CS may be a valuable raw material for a thermochemical conversion process like fast pyrolysis. Fast pyrolysis typically transforms a solid biomass into a liquid biofuel with solid char and gases as by-products. In fast pyrolysis, biomass is rapidly heated in the absence of oxygen at about 400-600C to generate vapour, which is quickly cooled down to room temperature. The condensed liquid is normally termed “bio-oil”. Fast pyrolysis was also used on some waste materials such as plastics [5], sewage sludge [6], pig compost [6], waste electrical and electronic equipment [7], wood waste [8], heavy metal contaminated biomass [9], waste furniture sawdust [2], biomass/waste tyres [8] and sawdust/waste printed circuit boards [10]. Thus, fast pyrolysis has been shown to be an efficient way to manage both hazardous and non-hazardous materials as it not only decomposes the wastes, but also produces valuable fuels at the same time. In 2010, Stals et al reported pyrolysis of biomass contaminated with heavy metal in a lab-scale semi-continuous reactor [9]. They showed that up to 49 wt% of bio-oil could be produced at 450C. The bio-oil contained 35 wt% of water and had a higher heating value of 15.8 MJ/kg. In addition, Heo et al studied waste furniture sawdust fast pyrolysis in a fluidised-bed reactor at 400-550C [2]. The waste furniture sawdust was contaminated with

5 solid particles including soil and sand. They achieved bio-oil yields of 42-58 wt%, the char yield of 20-38 wt% and the gas yield of 15-38 wt%. They also demonstrated that the pyrolysis temperature significantly affected the yields and the water content of bio-oil. Although Heo et al tested the contaminated sawdust waste from fast pyrolysis, they did not assess the effect of the contaminant material on product yield and properties [2]. Moreover, the contaminants of the biomass used by Stals et al [9] and Heo et al [2] were only solid particles. Unlike the heavy metal contaminated biomass and waste furniture sawdust, the CS from metal-working industries investigated in this study contained not only solid soil/dust/metals, but also mineral oils spilled from the working surface. The effect of these solid and liquid contaminants on fast pyrolysis of biomass is not yet well understood. Therefore, the impact of solid and liquid contaminants (soil/dust/metals and mineral oil) in sawdust from metal-working industries on yields and properties of fast pyrolysis products is investigated in this work. Fast pyrolysis experiments were carried out in a circulating fluidised bed (CFB) reactor. Before investigating the effect of the contaminants, the effect of the pyrolysis temperature was studied using the CS in the range from 400 - 600C in order to identify the optimum pyrolysis temperature of the biomass for maximising the bio-oil yield. The influence of the contaminants (solids and mineral oil) was investigated by pyrolysing three biomass samples – contaminated sawdust (CS), uncontaminated sawdust (UCS) and hexane extracted contaminated sawdust (HCS). For each experiment, mass balance was measured to obtain the product distribution. The properties of the liquid bio-oil and solid char were also determined.

2. Materials and methods 2.1 Biomass feedstock Biomass samples were obtained from a metal-working plant in Maha Sarakham Province, Thailand. The biomass was ground and sieved into 75-600 m. Their main characteristics are summarised in Table 1. The uncontaminated sawdust (UCS) was the sample before being used by the metal-working plant. The hexane-extracted contaminated sawdust (HCS) was obtained to observe the effect of the mineral oil absorbed in the sawdust. The CS contained ~24 wt% of mineral oil and ~6 wt% solid contaminant, whereas the HCS contained ~7 wt% solid contaminant. It is important to note that the solid contaminant is the solid added to the biomass due to contamination when the biomass is used as cleaning material and it is calculated as weight percentage in dry biomass. It becomes part of the ash in

6 the CS and HCS samples when burning, thus making the ash content of the CS and HCS samples higher than that of the UCS sample. In proximate analysis, the contents of moisture, volatile matter and ash were determined following ASTM E1756-01, E872-82 and E1755-01 methods, whereas the fixed carbon was calculated by difference. The proportions of carbon, hydrogen, nitrogen and sulphur were determined by a Leco CHNS Determinators analyser according to ISO/IEEC guide 22 and EN 45014 elemental analysis at the Center for Scientific and Technological Equipment (CSTE), Suranaree University of Technology, Nakhon Ratchasima Province, Thailand. The higherheating value (HHV) of the biomass was measured with a S.M.D. Torino Bomb Calorimeter following DIN 51900, while the lower heating value (LHV) was calculated:

( ) where

( )

(

)

is latent heat of vapourisation at 30°C (2.430 MJ/kg),

(1) is mass of water

produced from combustion of 1 kg of hydrogen ( = 8.936) [11] and H is weight percentage of hydrogen on dry basis. Table 1 shows that the CS had similar volatile matter content to the UCS, but higher ash content due to the presence of soil and metal particles. The CS had higher carbon content and lower oxygen content than the UCS ones, leading to a higher heating value. This is due to the presence of the mineral oil. Table 1 also shows that after extracting the CS with hexane to obtain HCS, the volatile matter decreased 18 wt%, the ash increased ~8 wt% and the fixed carbon increased 10 wt%. The decrease of the volatile matter results from the removal of the mineral oil. The increase of the ash and fixed carbon contents is due to the decrease of the volatile proportion. To identify the elements in the solid contaminants, the elemental composition of ash in biomass was determined by SEM-EDX (scanning electron microscopy with energy-dispersive Xray analysis). A JEOL JSM-6460LV scanning electron microscope was used at an accelerating voltage of 21 kV, a working distance of 11 mm and a spotsize of 49. The electron detector was secondary electron imaging (SEI). The SEM was connected with an Oxford Instruments INCA X-sight LN2 energy dispersive spectroscope. The results show that Fe and Ca are the major contaminants and Al, P, K, P and Mn are minor contaminants.

7 2.2 Fluidising medium Silica sand was used as a fluidising and heat transfer medium. Prior to each experiment, the sand was burnt at 575°C for 24 hours and sieved to a particle size of 75-212 µm. The sand had a bulk density of 1,282±2 kg/m3 and a particle density of 2,564±3 kg/m3. For each experiment, approximately 300 g of sand was applied. 2.3 Fast pyrolysis apparatus Fast pyrolysis of biomass was performed in a circulating fluidised-bed (CFB) reactor unit, designed and constructed at the Bio-Energy and Renewable Resources Research Unit, Maha Sarakham University, Thailand. Its schematic diagram is shown in Fig.1. Its main components are a biomass hopper, a reactor, a preheater, a char combustor, two cyclone separators, a hot filter and a bio-oil collection set. The biomass hopper was made of a PVC tube and had a capacity of 0.01 m3 and could hold approximately 1.5 kg of the CS. The biomass particles could be fed to the reactor by nitrogen flow entrainment via a feeding tube with a cooling jacket to prevent premature pyrolysis. The reactor, preheater, char combustor, cyclones and hot filter were made from 304 stainless steel tubing. The reactor or riser had an internal diameter of 14 mm and the height of 500 mm. The pre-heater was used to heat the inlet nitrogen and air. The char combustor had an internal diameter of 51 mm and a height of 152 mm. The first cyclone was designed to separate the silica sand from char and pyrolysis vapour. However, part of the coarse char particles was also circulated with the silica sand and combusted in the char combustor. The second cyclone was designed to remove fine char particles from pyrolysis vapour and collect them in the char pot. The hot filter was a fixed bed of glass wool. For each experiment, about 10 g of glass wool was put in the filter and it was changed for every run. The bio-oil collection set included a water-cooled condenser, an electrostatic precipitator (ESP), two dry ice/acetone condensers, three bio-oil pots and a cotton wool filter. The water-cooled condenser was a double tube heat exchanger. The ESP operated at 12 kV DC was used to aid the bio-oil collection. The liquid product from the water-cooled condenser and the ESP was mixed and collected in Bio-oil pot 1 (see Fig 1). The dry ice/acetone condensers were of cold-finger type. The temperature of the dry ice and acetone mixture was about -70C. The liquid condensed in the dry ice/acetone condensers was collected in Bio-oil pots 2 and 3. The cotton wool filter was made from a PVC tube and was used to filter some volatile components or moisture left in the exit gas prior to the collection of the non-condensable gas.

8 2.4 Fast pyrolysis experiments The pyrolysis temperatures measured and controlled at TC3 (see Fig.1) were set at 400, 450, 500, 550 and 600C to determine the optimum temperature for bio-oil production. The optimum temperature was then used for two experiments using the UCS and HCS biomass samples. These two experiments investigated the effects of solid and liquid contaminants on products yields and bio-oil properties. For all experiments, the preheater temperature (TC1) was set 50C above the pyrolysis temperature. The temperatures of the cyclone (TC6) and the hot filter (TC7) were controlled at ~420C to prevent re-condensation, re-polymerisation or secondary cracking of the pyrolysis vapour. The nitrogen flow at the top (FC4) and the side (FC3) of the hopper was 2 L/min, whereas the fluidising nitrogen flow (FC2) was 4 L/min. The air flow rate to the char combustor was 1.5 L/min. For each experiment, approximately 100 g of biomass was fed to the reactor at a feed rate of 100 g/h. The total experimental run duration was 1 hour. When the pyrolysis experiment finished, the reactor and heated parts were left to cool to room temperature. Then, the reactor unit was dismantled and each part was weighed for mass balance calculation. 2.5 Reproducibility (Precision) Reproducibility of the bio-oil production in the circulating fluidised-bed reactor was checked at five pyrolysis temperatures (400, 450, 500, 550 and 600C). Each pyrolysis temperature was tested in triplicate. It was found that the reproducibility, which is calculated as the average standard deviation (S.D.) of each pyrolysis temperature experiment, was ± 0.7% for total bio-oil ± 0.4% for char, ± 0.7% for gas, ± 0.2% for heavy bio-oil, ± 0.1% for light bio-oil, ± 0.2% for organic bio-oil and ± 0.1% for reaction water yields.

2.6 Mass balance The liquid bio-oil, solid char and non-condensable gases are the main products from fast pyrolysis. The yields of each product were calculated by weighing all parts of the fast pyrolysis systems that mainly comprised of biomass, silica sand, circulating fluidised-bed reactor, cyclone separators, hot filter and product collection unit, before and after each experiment. The total bio-oil yields were determined as a liquid weight from the product collection unit including water-cooled condenser, ESP, bio-oil pot 1, dry ice/acetone condensers, bio-oil pot 2, bio-oil pot 3 and cotton wool filter. The char yields were the

9 combined solid masses collected from the reactor, cyclones, hot filter, transfer line and the solids in bio-oil. The gas yields were calculated by difference. In fact, the gas yield can be measured using a volumetric gas meter, a pressure gauge and a thermocouple. The total volume, pressure and temperature data can be used together with the gas composition measured from the GC to calculate the mass yield of the gas using an ideal gas correlation. However, this method was not adopted in this work since the other method is simpler and give comparable results.

2.7 Bio-oil analysis The bio-oil products collected from the water-cooled heat exchanger and electrostatic precipitator (ESP), or heavy bio-oil, was analysed for water content, solids content, ash content, pH value, density, high heating value, viscosity and stability. For light bio-oil obtained from the dry ice/acetone condensers, only water content and pH value were determined. Each analysis was performed in triplicate.

2.7.1 Water content The water content of the bio-oil was analysed following ASTM E203 by volumetric Karl Fischer titration (Mettler Toledo V20) with Merck CombiTitrant 5 keto as the titration reagent and Merck Combi solvent keto as the titration solvent. 2.7.2 Solids content Solids content of bio-oil was determined following ASTM D7579 as methanoldichloromethane (1:1) insoluble material by using a vacuum filtration technique. Approximately 1-2 g of bio-oil was filtered through a pre-dried and pre-weighed Whatman No. 3 qualitative filter paper with particle retention of 6 m. The bio-oil was then washed with dichloromethane until the filtrate was clear to ensure that there was no organic liquid left on the filter paper. The filter paper with the residues was air-dried for 15 min, dried in an oven at 105C for 30 min, cooled in a desiccator and weighed. The solids content was then calculated as the percentage of the solid residues in the bio-oil. This method was suggested by Oasmaa and Peacocke [12]. 2.7.3 Ash content The ash content of bio-oil was determined according to DIN EN 7. Approximately 3 g of bio-oil sample in a pre-dried and pre-weighed crucible was heated at 105C for 12 hours to remove water and volatile compounds and to prevent foaming and splashing. The

10 sample was then heated at 775C for 24 hours or until constant weight. The percentages of the solid residues of the initial bio-oil were calculated as ash content.

2.7.4 pH value The bio-oil pH was measured by a UB-10 Denver instrument pH meter. Prior to the analysis the pH meter was calibrated with buffer solutions of pH 4, 7 and 10. Approximately 10 ml of bio-oil sample from each experimental run was analysed.

2.7.5 Density The density of bio-oil was determined using a 5 ml density bottle at room temperature (~30°C).

2.7.6 Heating value The higher heating value (HHV) of bio-oil on as produced-basis was determined by an S.M.D. Torino bomb calorimeter according to the DIN 51900 method. Approximately 1 g of bio-oil sample in a cap was placed in a bomb or reaction chamber. The bomb was filled with an excess amount of oxygen. The bomb was then installed in a bucket filled with 2,000 ml of water. The bio-oil sample was ignited by an electrically heated wire. The change of the water temperature was recorded by a computerised system. The bomb calorimeter was calibrated with benzoic acid.

2.7.7 Viscosity and stability The kinematic viscosity of bio-oil was measured according to ASTM D445. An opaque Cannon-Fenske viscometer (size -350) was used at a constant temperature of 40C. The stability of bio-oil was determined as the percentage of the viscosity change of fresh and aged bio-oils. The viscosity of the fresh bio-oil ( whereas that of aged bio-oil (

) was measured within 24 hours of production,

) was measured after storing bio-oil in a closed container at

80C for 24 hours, which is equivalent to storing at room temperature for 1 year [13]. The viscosity change and the ageing rate were calculated by equations (2) and (3): viscosity

(2)

ein rate

(3)

11 2.7.8 GC/MS analysis Bio-oil was diluted in methanol-dichloromethane (1:1) to obtain 10 wt% concentration. The samples were filtered through a Filtrex nylon filter with 0.2 µm pore size prior to the injection. The gas chromatography/mass spectrometry (GC/MS) analysis of biooil was conducted using an SHIMADZU Gas Chromatograph Mass Spectrometer model GCMS-QP2010. The separation was made on a 30 m × 0.25 mm id Restex Rtx-5MS column (Restex, USA) with 0.25 m film thickness. Its phase composition was 5% diphenyl -95%dimethylpolysiloxane. The GC oven temperature was held at 60°C for 2 min and programmed to rise from 60°C to 270°C at 5°C/min. The oven was maintained at this final temperature for 5 min. The injector temperature was 270°C with a split ratio of 100. Helium was the carrier gas with a linear velocity of 40 cm/s. The capillary column was directly connected to a metal quardrupole mass filter with pre-rod Mass Analyser and Electron multiplier detector. The mass spectrometer was operated with electron impact (EI) mode at ion source and interface temperatures of 250 and 230°C, respectively, with ionisation energy of 70 eV. The mass range from m/z 20 to 650 was scanned with a scan event of 0.5 s. Data acquisition and processing was performed using SHIMADZU LabSolutions GCMS solution software.

2.8 Char analysis Char samples were analysed for their higher heating value. The method for HHV of the char was similar to that for bio-oil samples as described earlier in section 2.7.6

2.9 Non-condensable gas analysis Non-condensable gases were analysed with a gas chromatograph (GC) (Shimadzu GC8A) equipped with a thermal conductivity detector (TCD). The columns were Porapak N (80/100 SS 2.3 mm I.D. × 1 m) and Unibeads C (60/80 SS Col. 3 mm. I.D. × 2 m). The carrier gas was high purity argon (99.995%). The concentrations of hydrogen (H2), carbon monoxide (CO), carbon dioxide (CO2), nitrogen (N2), methane (CH4), ethene (C2H4) and ethane (C2H6) were determined.

12 3. Results and discussion 3.1 Product yields 3.1.1 Effect of pyrolysis temperature on product yields The effects of pyrolysis temperature in the range of 400-600°C on the yield of the products derived from the contaminated sawdust sample are shown in Fig. 2. The main products include total bio-oil, char and gas. The total bio-oil is the combination of the heavy bio-oil collected from Bio-oil Pot 1 and the light bio-oil collected in Pots 2 and 3 (see Fig. 1.). Fig. 2(a) shows yields for organic bio-oil and reaction water components. The organic bio-oil is the non-water part of the liquid product. Its yield was determined by calculation based on the water content of the heavy and light phases of the bio-oil, rather than physical separation. Therefore, the liquid part that is not organic bio-oil is merely water generated by pyrolysis reactions such as dehydration. It is important to note that the “reaction water” is water that produced from pyrolysis reactions. The original water derived from biomass is not included in the reaction water since the calculation is based on dry biomass basis and the mass of water in the biomass feedstock was subtracted from the total water in the liquid biooil. According to Fig. 2, it is possible to analyse the effect of the pyrolysis temperature on products yields by considering two steps of the temperature change (400-500°C and 500600°C). Fig. 2(a) shows that when the pyrolysis temperature was increased from 400°C to 500°C, the total bio-oil yield increased from 56 wt% to 67 wt% on dry biomass basis. This corresponds to the reduction of the char yields from 21 wt% to 18 wt% and and gas yields from 23 wt% to 15 wt%. This implies that the bio-oil yield increase of 11 wt% came from the non-condensable gas of 8 wt% and the char of 3 wt%. The shift of gas to bio-oil with increase of the pyrolysis temperature in this case is somewhat different from typical biomass fast pyrolysis. This could be related to the difference in the biomass feedstock as the current sawdust was contaminated with mineral oils and metals. For example, when a typical woody biomass, cassava rhizome, was pyrolysed in a fluidised-bed reactor, when the temperature increased from 400°C to 472°C, the total bio-oil yield increased from 55 wt% to 63 wt% [14]. This 8 wt% increase was attributed to reduction of char yield, rather than gas yield. This is because the char yield decreased from 40 wt% to 25 wt%, whereas the gas yield increased from 5 wt% to 12 wt% [14]. This confirms that the contaminated sawdust behaved differently from typical woody biomass. Nonetheless, jatropha oil cake pyrolysis in a fluidised-bed reactor showed similar trend to the current findings. Raja et al [15] found that when increasing the pyrolysis temperature from 350°C to 500°C, the total bio-oil increased from 42 wt% to 64 wt% in conjunction with a reduction of char yield from 15 wt% to 4 wt% and gas

13 yield from 43 wt% to 32 wt% [15]. In this case, the 22 wt% increase of the bio-oil yield could be derived from gas yield as well. The increase of the pyrolysis temperature from 400°C to 500°C that led to the reduction of the gas yield in Fig. 2(a) could be due to the increased thermal decomposition of some heavy mineral oil in the contaminated sawdust leading to the production of additional hydrocarbon gases. These gaseous hydrocarbons might be involved in the pyrolysis reactions in a similar way to the recycling of product gas. Heo et al reported that when the product gas stream containing CO, CO2 and C1-C4 hydrocarbons was recycled to the reactor, the total bio-oil yield increased from 58 wt% to 65 wt% when waste furniture sawdust was pyrolysed, whereas the char yield was constant and the gas yield decreased from 14 wt% to 7 wt% [2]. When the temperature increased beyond 500°C to 600°C, the bio-oil yield reduced from 67 wt% to 58 wt%, whereas the char yield decreased from 18 wt% to 16 wt% and the gas yield increased from 15wt% to 26 wt%. This reduction of the bio-oil yield is attributed to the secondary thermal cracking of the pyrolysis vapour to generate non-condensable gases. Fig. 2(a) also shows that the change of the organic bio-oil yield with temperature tracks the total bio-oil yield since the reaction water yields are nearly constant at 11-13 wt%. Few literature studies of biomass fast pyrolysis reported the effect of pyrolysis temperature on the reaction water yield. Only the reaction water yields of palm oil empty fruit bunches (EFB) pyrolysis were reported to be 14-15 wt% for pyrolysis temperature of 400-600°C [16]. The contaminated sawdust pyrolysis in this work gave slightly less reaction water than the EFB biomass pyrolysis. The optimum pyrolysis temperature for contaminated sawdust is 500°C, the yields were - for total bio-oil – 67%, organics – 55% and reaction water 12 wt%. This total bio-oil yield is about 6 wt% lower than that reported by Lappas et al when clean biomass (Lignocell HBS 150-500) was pyrolysed in a circulating fluidised bed reactor [17]. Nevertheless, Lappas et al reported a maximum organic liquid yield of 55 wt% together with reaction water yield of 18 wt% at the riser or reactor temperature of 457°C [17]. Thus, contaminated sawdust reaction water yield was significantly lower than for typical biomass. Although the contaminated sawdust investigated in this work contained a significant (24%) amount of mineral oils such as engine oil, gear oil, gasoline and diesel, the maximum total bio-oil yield (67 wt%) was not extraordinarily high compared to typical biomass such as sawdust [18], cassava rhizome and stalk [14] and eucalyptus bark [19]. These biomasses gave maximum bio-oil yields in the range of 61-65 wt% [14, 18, 19]. The solid contaminants may be a possible explanation for this. The influence of solid metals present in biomass during

14 pyrolysis has been studied by several researchers [20-25] and found that the inorganic species can catalyse biomass decomposition and char-forming reactions, resulting in the reduction of liquid yields and the formation of char and non-condensable gases. It is also well-known that the metals influence the thermal decomposition mechanism during fast pyrolysis by enhancing the fragmentation (ring scission) of the monomers making up the macro-polymer chains [23, 26]. From Table 1, CS samples contained 11% ash. This ash was composed of some metals, soil and dust, which could act as catalyst for char forming or vapour cracking reactions, thus producing char and permanent gas at the expense of bio-oil. Nevertheless, the total bio-oil yield from the contaminated sawdust in this work was higher than those from waste furniture sawdust (58wt%) [2] and heavy metal contaminated biomass (40 wt%) [9]. Fig. 2(b) compares the yields for heavy and light bio-oils. The effect of the pyrolysis temperature on both portions of bio-oil is somewhat similar to that on the total bio-oil. At 500°C, the maximum yields were 54 wt% for heavy and 13 wt% for light bio-oils. The yields of these two fractions can be controlled by the temperature of condenser cooling water. If the temperature is increased, the bio-oil would shift from the heavy fraction to the light fraction. In this way, the bio-oil properties can also be controlled, especially the water content, heating value, viscosity and stability.

3.1.2 Effect of sawdust contamination on product yields

Fig. 3(a) shows that the product yields for CS and UCS were somewhat similar. The CS gave slightly lower (~2 wt%) total bio-oil yield and slightly higher gas yield compared to the UCS, whereas their char yields were similar at 18 wt%. HCS sample yields were significantly different from CS and UCS. The bio-oil yield decreased to 46 and the char increased to 39 wt%. This is due to the lower volatile matter content and the higher ash content of the HCS sample [27, 28]. Noting the heavy and light fraction in Fig. 3(b), it is apparent that the main influence on the total bio-oil yield was the heavy faction. Interestingly, Fig. 3(c) shows that although the CS bio-oil yield was lower than that of UCS, its organic bio-oil was significantly higher 55 wt% compared to 44 wt%. This is due to the lower reaction water of the CS biooil ~12 wt% compared to 25 wt% of the UCS one. Fig. 3(c) also shows that the organic and reaction water yields of the HCS were lower than those of the UCS - the same trend as the total bio-oil yield (Fig. 3(a)) and the heavy and light bio-oil (Fig. 3(b)).

15 Considering Fig. 3(a), (b) and (c) together, it can be noted that the CS sample containing 24 wt% mineral oils and 6 wt% solid contaminants gave maximum organic bio-oil yield. This part of bio-oil consisted of the degradation products of mineral oils together with cellulose, hemicellulose and lignin devivatives. Although the CS contained high solids, its total bio-oil yield was only slightly lower than that of the UCS. This implies that the presence of mineral oils significantly affected the bio-oil yield, specifically the organic part. In addition, the effect of solid contaminants can be understood by comparing the yields for HCS and UCS. HCS containing 6 wt% solid contaminants without the mineral oils gave lower biooil yields for all components (heavy and light bio-oils or organics and reaction water) than the UCS. This bio-oil reduction caused a significant increase (21 wt%) of the char yield and a small increase (1 wt%) of the gas yield. From this, it can be deduced that the mineral oil contaminants increased the organic bio-oil at the expense of the reaction water and the solid contaminants lowered the bio-oil proportion with the increase of the char yield.

3.1.3 Effect of pyrolysis temperature on composition of gaseous products The composition of non-condensable gases obtained from fast pyrolysis of CS samples at 5 different temperatures is shown in Fig. 4. Surprisingly, only three gases were detected: H2, CH4 and C2H4, whereas CO2 and CO, which are typically found from biomass pyrolysis such as empty fruit bunches [16], waste furniture sawdust [2], cassava plants [29] and jatropha oil cake [15] were not detected. In fact, it is expected that CO2 and CO was produced from lignocellulosic part of the feedstock. However, significant propotion of H2, CH4 and C2H4 was produced from contaminated mineral oils which eclipsed the CO2 and CO proportion due to detection limit of the instrument. Methane was the main component. Increasing the temperature from 400°C to 500°C increased H2 composition at the expense of the CH4 composition. Further increase of the temperature to 600°C did not increase H2 concentration but rather increased the proportion of C2H4 from non-dectable to 22%. The increase of C2H4 is expected to be due to the increased thermal decomposition of cellulose and the contaminated mineral oil. Lanza et al reported the increase of C2H4 yield from 5 wt% to 14 wt% when the pyrolysis temperature in a free-fall reactor increased from 700 to 900°C [30]. In addition, Lam et al found when pyrolysing waste automotive engine oil in a microwave-heated reactor that the C2H4 composition increased from 8 vol% at 500°C to 21 vol% at 550°C and 24 vol% at 600°C [31]. Based on the product gas yield, the higher heating values (HHV) and lower heating values (LHV) of the product gas produced at different pyrolysis temperatures were calculated

16 and the results are shown in Table 2. The LHV of the product gas obtained at pyrolysis temperature of 400°C was 32 MJ/Nm3 and reduced to 29 and 28 MJ/Nm3 with the increase of the temperature to 450 and 500°C, respectively. This corresponds to the decrease of CH4 composition. However, further increase to 550°C and 600°C led to the LHV increase to 33 and 34 MJ/Nm3, respectively. This was due to the increase of C2H4. The LHVs of the product gas produced from fast pyrolysis of pine powder at 550°C in a circulating fluidised bed reactor were in the range of 21-24 MJ/Nm3 [32]. This is slightly lower than the CS gas. Thus the mineral oil contaminants enhanced the heating value of the product gas to a small extent.

3.1.4 Effect of sawdust contamination on composition of the gaseous products The effect of liquid and solid contaminants on pyrolysis gas composition is shown in Fig. 5. Clearly, the composition of gases from UCS and HCS are similar. The samples differ only in presence of the solid contaminants, so it can be concluded that the solids did not affect the gas composition. Interestingly, CS containing mineral oils and solids gave significantly different gas composition from the uncontaminated sample. Methane and hydrogen increased to a point that CO, CO2 and C2H4 could not be detected. Based on the composition of the UCS and HCS gases, their lower heating values (LHV) were 9-10 MJ/Nm3, compared with 28 MJ/Nm3 for CS gas. This confirms the positive effect of the mineral oil contamination on the product gas. Since the gas from fast pyrolysis of contaminated sawdust had a relatively high LHV, it may be used as a potential fuel for gas turbine power generation. However, it is likely that the gas may contain Cl in the gas stream and can be harmful to the devices. Therefore, it is suggested that these chlorinated compounds must be determined and removed prior to using the gas as fuel. 3.2 Product properties 3.2.1 Effect of pyrolysis temperature on product properties Bio-oil samples produced from fast pyrolysis of contaminated sawdust (CS) at several temperatures were analysed for water content, solids content, ash, pH, density, higher heating value and viscosity. The results are summarised in Table 3. For water content, both fractions (heavy and light) were analysed. It can be seen that the water content of heavy bio-oil decreased from 12 wt% at 400°C to about 4 wt% at 450-600°C. The change of the bio-oil water content due to the increase of pyrolysis temperature found in this work differs significantly from literature. Heo et al [2] reported that, for furniture sawdust, their bio-oil water content increased from 40 wt% to 60 wt% when temperature increased from 400°C to

17 550°C. Similarly, for the same temperature increase, Pattiya and Suttibak [14] found that the water content of cassava rhizome bio-oil increased from 15 wt% to 24 wt%. The reduction of the water content with pyrolysis temperature for CS is ascribed to the mineral oil in the biomass. When the temperature was increased to 450°C, the mineral oil vapourised and recondensed to become liquid portion. This is consistent with the results of Lam et al [31] that waste automotive engine oil gave significantly higher pyrolysis oil yield when the temperature was increased from 400°C to 450, 500 and 550°C. For light bio-oil, their water content was not influenced by the pyrolysis temperature and was ~76-80 wt%. Since this fraction contained mainly water, it cannot be used as fuel, but may be used as raw material for chemical production such as acids or pesticide. Table 3 also shows that the solids and ash contents of heavy bio-oil were constant with the pyrolysis temperature range. The solids content was ~0.4 wt%, whereas the ash content was 0.1 wt%. In addition, the pyrolysis temperature did not affect the pH and density of the bio-oil. The heavy bio-oil pH of 3.4-3.9 was slightly higher than that of the light bio-oil, which was about 2.6-2.8. It is interesting to note that the density of heavy bio-oil was 0.8-0.9 kg/dm3. This is lower than that of typical bio-oil, which is usually 1.1-1.3 kg/dm3 [33]. The CS bio-oil density is similar to that of petroleum oils or their pyrolysis liquid products. The pyrolysis oil produced from waste automotive engine oil in a microwave-heated pyrolyser was 0.7 kg/dm3 [34]. Therefore, mineral oil contaminants significantly affect the pyrolysis liquid density. The lower heating value (LHV) of CS heavy bio-oil was 28 MJ/kg at the pyrolysis temperature of 400°C and increased to 30 MJ/kg at 450 and 500°C. Increase beyond 550°C did not significantly affect the LHV. The LHV increase corresponds to the decrease of water content or the expected increase of the mineral oil pyrolysis liquid product. This relationship between the bio-oil heating value and the pyrolysis temperature is similar to reports from Garcia-Perez et al [35] where oil mallee woody biomass was fast pyrolysed in a fluidised bed reactor at 350-580°C.

Only heavy bio-oil was measured for viscosity, whereas the viscosity of the light biooil and the mixture of heavy and light bio-oils was determined. This is because only heavy bio-oil can be used as fuel, whereas the light phase contained significant proportion of water, thus having very low viscosity. Therefore, the light bio-oil was not suitable for fuel application. At 400°C, the kinematic and dynamic viscosities of fresh CS heavy bio-oil were 82 cSt and 73 cP and they increased with the pyrolysis temperature to 229 cSt and 191 cP,

18 respectively, at 550°C. Then, further increase of the temperature to 600°C resulted in a decrease of the viscosity to 182 cSt or 159 cP. Therefore, it is obvious that the pyrolysis temperature affected the kinematic and dynamic viscosities of the heavy bio-oil since it affected the water content. The bio-oil water content is known to significantly influence the viscosity. Oasmaa et al reported that when bio-oil from pine reduced its water content from 33 wt% to 16 wt%, its viscosity increased from 14 to 35 cSt [36]. A similar trend was also reported by Garcia-Perez et al who found that the dynamic viscosity of their bio-oil increased from 50 mPa.s at the pyrolysis temperature of 350°C to 100 mPa.s at 450°C and decreased to 40 mPa.s when the temperature was further increased to 580°C [35]. They related the biooil viscosity with its water content and the amount of water-insoluble compounds. In other words, high bio-oil viscosity resulted from lower water content and higher water-insoluble compounds [35]. The stability of bio-oil can be assessed through the viscosity change and the ageing rate. The viscosity change and the ageing rate increased when increasing the pyrolysis temperature from 400°C to 450°C. Further increase of the temperature to 600°C did not significantly affect the stability. This indicates that the most stable bio-oil was obtained at 400°C. This trend corresponds to the change of water content: the bio-oil from biomass pyrolysis is more stable when the water content is high. However, if the water content of biooil is too high, a phase separation could take place. Diebold and Czernik also showed that when the water content of their bio-oil produced from biomass in a vertex reactor increased from 20 to 25 wt%, the ageing rate decreased from 2.5 to 2.2 cP/h [37]. Table 3 also shows the effect of pyrolysis temperature on char heating value: the heating value of char from fast pyrolysis of CS is independent of the temperature. This is in good agreement with literature when alkaline copper quaternary-treated wood and sugar cane straw were pyrolysed in fluid bed reactors [38, 39]. The LHV of the treated wood char was around 28-29 MJ/kg for the pyrolysis temperatureof 353-511°C [38], whereas that of straw char was in the range of 12-13 MJ/kg for 470-600°C [39]. 3.2.2 Effect of sawdust contamination on product properties At 500°C, the total bio-oil and the organics reached its maximum yield (Fig.2). Therefore, this temperature was adopted for the pyrolysis of uncontaminated (UCS) and hexane-extrated contaminated sawdust (HCS) in order to investigate the effect of contamination on bio-oil and char properties as summarised in Table 3.

19 Since the heavy bio-oil is the main pyrolysis liquid product, its main properties were compared with those of the Grades G and D biofuel according to ASTM D7544-12 [33]. The water content of all heavy bio-oils produced in this work met the requirement of 30 wt% maximum. The UCS had highest water content (23 wt% for heavy and 88 wt% for light biooil) and CS (4 wt% for heavy and 76 wt% for light bio-oil). This shows that contamination with mineral oils and metals lowered the water content. When comparing the water content of CS and HCS bio-oils, the lower water content of CS bio-oil may be attributed to the mineral oils in the biomass feedstock. Table 1 shows that the oil contaminant in the CS sample was 24 wt%. Therefore, part of the mineral oil vapourised and recondensed adding to non-aqueous portion of the pyrolysis liquid products. To measure the effect of solid metal contaminants, the HCS and UCS bio-oils are compared since metal contaminants were only in the HCS samples. The results show that the metals could reduce the water content of bio-oil. There are two hypotheses for these unexpected results. The first is that the HCS still contained some residual mineral oils. To test this hypothesis, the HCS bio-oil density can be compared to the CS and UCS bio-oils. The density of the CS bio-oil (0.9 kg/dm3) was much lower than those of the HCS and UCS ones (1.2 kg/dm3). To a certain extent, this could imply that the mineral oils existed mainly in the CS sample, whereas HCS contained negligible residual mineral oil. As a consequence, the first hypothesis cannot well explain why the water content of the HCS bio-oil was lower than that of the UCS one. In the second hypothesis, it is expected that the metal contaminant powder could aid heat transfer during pyrolysis reaction, thus increasing the heating rate. It is well-known that reaction water is reduced when increasing biomass heating rate [40]. For example, the water content of relatively-slow pyrolysis liquids, such as those from fixed bed reactors, was higher than that of the fast pyrolysis liquids [41]. Table 3 also shows that the contaminants did not affect the solids content, ash content and pH of both bio-oil fractions. Although the solids content only met the Grade G biofuel requirement, the ash content met the requirement for both grades. The solids and ash content can be further reduced or improve by hot vapor filtration such as glass wool fixed bed filter [14] and moving-bed granular filter [42]. The higher heating values (HHV) and lower heating values (LHV) on wet and dry bases are tabulated. It is apparent that the CS bio-oil had the highest HHV and LHV on both bases. This is unsurprising due to the presence of the mineral oils in the CS feedstock. Since mineral oil from petroleum contains negligible oxygenated compounds, thus possessing high heating value, typically higher than 40 MJ/kg, the presence of small quantity of these mineral

20 oils can then significantly increase the overall heating value of the pyrolysis liquid. On wet basis, the HHV and LHV of HCS bio-oil was higher than that of the UCS one. This is owing to the much lower water content of the UCS liquid. Nevertheless, on dry basis, the HCS biooil had nearly the same HHV and LHV as the UCS one. This can, therefore, confirm that there was no mineral oil left after the hexane extraction. According to the ASTM D7544-12, the pyrolysis liquid viscosity should be lower than 125 mm2/s (cSt) or equivalent to 150 cP if the liquid density is 1.2 kg/dm3 in order to be used as biofuel in industrial burners. The current results show that only uncontaminated and hexane extracted contaminated sawdust bio-oils met this viscosity requirement. However when the bio-oils were aged for a period equivalent to1 year, their viscosity increased significantly and only UCS bio-oil viscosity was lower than 125 cSt. It can be noticed that the bio-oils viscosity was directly related to their water content: the higher the water content, the lower the viscosity. This relationship has already been reported [36]. Therefore, the effect of mineral oil and solid metal contamination on bio-oil viscosity can be explained by the changes of the water content: the presence of mineral oils and solid metals led to the increase of viscosity. For uncontaminated sample, the fresh bio-oil viscosity was 18 cSt or 22 cP. This is similar to literature data when wheat straw [28], cassava residues [14], paddy residues [43] and eucalyptus bark [19] were pyrolysed and the bio-oil viscosities was around 5-16 cSt or 619 cP. To measure the bio-oil stability, the percentage of the viscosity change and the ageing rate were calculated. It was found that of the viscosity changes were 34% for CS, 41% for HCS and 55% for UCS. However, the ageing rate based on kinematic and dynamic viscosity was higher for CS bio-oil than for HCS and UCS bio-oils. Therefore, it is not possible to conclude that the stability of the bio-oil was improved or worsen when the biomass is contaminated with the mineral oils and solid metals. To chemically observe the influence of the contaminants on bio-oil products, GC/MS analysis of the heavy bio-oils derived from CS, UCS and HCS was performed. The chromatograms are shown in Fig.6 with main identified components and Table 4 shows all identified chemicals with the percentages of chromatographic peak areas. It can be seen that the chemicals found in CS bio-oil are significantly different from those in UCS and HCS biooils. It is clear that the CS bio-oils contained large proportion of hydrocarbon compounds, which was influenced by the petroleum oil contaminants. It is worthwhile to note that the hydrocarbons identified in the CS bio-oil including dodecane (C12H24), octadecene (C18H36), phenanthrene (C26H48), hexacosane (C26H54), pentadecene (C15H30), eicosene (C20H40),

21 nonadecene (C19H38) and tricosane (C23H48) were also found in pyrolysis of waste lubricating oil [44], waste machinery oil [45], oilfield sludge [46] and waste automotive engine oil [34], thus implying that the liquid contaminants contained these oils. The influence of metal contaminants on bio-oil chemical composition can be noticed by comparing the identified chemicals from UCS and HCS bio-oils. It is apparent that the presence of metals led to the reduction of phenolic compounds such as 2,6-dimethoxy phenol and 2,6-dimethoxy-4-(2propenyl) phenol with the production of certain carbonyl compounds such as 2-butanone, propanal and 2(5H)-furanone. The char LHVs were ~18 MJ/kg for CS and HCS, and 23.5 MJ/kg for UCS. It is clear that mineral oil did not effect the char heating value as the LHVs and HHVs of the CS and HCS were similar. UCS char had the highest heating value because the original biomass contained less ash and no additional solid contaminants. Consequently, it can be concluded that the solid contaminants led to a reduction of the char heating value. Nonetheless, CS char still had higher HHV than the chars derived from fast pyrolysis of other types of biomass such as sugar cane straw [39] and bamboo sawdust [47] for which the char LHV was ~13 MJ/kg. 4. Conclusions Fast pyrolysis of contaminated sawdust in a circulating fluidised bed reactor was significantly influenced by the reaction temperature and the liquid and solid contaminants. Increasing the pyrolysis temperature tended to reduce bio-oil water content to a minimum of ~4 wt%, while increasing its LHV and viscosity and decreasing its stability. The contamination with mineral oils gave positive results by increasing the organic bio-oil yield, especially hydrocarbon components, reducing the reaction water and increasing the heating value of the non-condensable gas by nearly 3-fold. Both solids and liquid contaminants did not change the bio-oil pH, solids and ash content, but increased its viscosity and LHV, as well as decreased the char LHV. Acknowledgment Financial support from Mahasarakham University under the contract number 5711017/2557 is gratefully acknowledged.

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25 Figure Captions Fig. 1. Schematic diagram of the fast pyrolysis unit.

Accepted Manuscript Title: Fast Pyrolysis of Contaminated Sawdust in a Circulating Fluidised Bed Reactor Author: Keyoon Duanguppama Nuchida Suwapaet Adisak Pattiya PII: DOI: Reference:

S0165-2370(15)30448-4 http://dx.doi.org/doi:10.1016/j.jaap.2015.12.025 JAAP 3644

To appear in:

J. Anal. Appl. Pyrolysis

Received date: Revised date: Accepted date:

11-7-2015 14-12-2015 31-12-2015

Please cite this article as: Keyoon Duanguppama, Nuchida Suwapaet, Adisak Pattiya, Fast Pyrolysis of Contaminated Sawdust in a Circulating Fluidised Bed Reactor, Journal of Analytical and Applied Pyrolysis http://dx.doi.org/10.1016/j.jaap.2015.12.025 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

27 Fig. 3. Effect of sawdust contamination on the yields of (a) main products (b) heavy bio-oil and light bio-oil (c) organic bio-oil and reaction water

(a)

(b)

(c)

28 Fig. 4. Effect of pyrolysis temperatures on composition of gaseous products

29 Fig. 5. Effect of sawdust contamination on composition of gaseous products

30 Fig. 6. Chromatograms of bio-oils produced from the three sawdust samples at a pyrolysis temperature of 500C

31 Tables Table 1 Characteristics of sawdust samples.

Analysis Proximate analysis (wt%, dry basis) Moisturea Volatile matter Fixed carbonb Ash Oil contaminant (wt%) Solid contaminant (wt%) Ash elemental composition (ppm in dry biomass) Magnesium (Mg) Aluminium (Al) Silicon (Si) Phosphorus (P) Chlorine (Cl) Potassium (K) Calcium (Ca) Manganese (Mn) Iron (Fe)

Contaminated sawdust (CS)

Uncontaminated sawdust (UCS)

Hexane-extracted contaminated sawdust (HCS)

6.1±0.1 81.6±0 7.2±0.1 11.2±0.1 23.7±0.0 6.1±0.0

7.8±0.1 82.9±0.2 10±0.5 7.1±0.2 N/A N/A

1.1±0.1 63.8±0 17.2±0.1 19±0.0 N/A 6.8±0.0

5,958±3 3,039±1 10,771±1 2,778±1 2,359±1 6,978±2 43,885±10 2,681±1 33,570±12

15,489±6 627±23 23,632±11 655±1 731±23 5,050±7 22,445±19 1,640±3 731±6

9,316±2 4,509±2 19,507±3 4,332±2 1,989±2 8,677±3 91,434±5 3,616±2 46,620±7

62.6±0.8 9±0.3 0.1±0.2 0.3±0.0 28.1±0.5 567±1 1,418±2

53.4±0.8 8±0.3 0.8±0.2 0.1±0.0 37.8±0.5 367±1 918±1

50.5±0.8 6±0.3 1±0.2 0.1±0.0 42.3±0.5 459±1 1,146±1

23.2±1 21.6±1

19.2±1 17.7±1

19.7±1 18.7±1

Ultimate analysis (wt%, dry, ash-free basis) Carbon Hydrogen Nitrogen Sulfur Oxygenc Bulk density (kg/m3) Particle density (kg/m3) Heating values (MJ/kg, as-receive basis) Higher heating value (HHV) Lower heating value (LHV) a As-received basis b c

Calculated from 100 - Volatile matter - Ash

Calculated from 100 - Carbon - Hydrogen – Nitrogen - Sulfur

32 Table 2 Heating values of pyrolysis gas Biomass feedstock

Contaminated Sawdust (CS)

Uncontaminated Sawdust (UCS) Hexane-extracted Contaminated Sawdust (HCS)

Pyrolysis temperature (°C) 400 450 500 550 600

HHV (MJ/Nm3) (MJ/kg) 35.1 36.8 32.7 34.2 31.5 32.9 36.2 37.2 37.8 38.7

LHV (MJ/Nm3) (MJ/kg) 31.5 33.1 29.3 30.6 28.2 29.5 32.9 33.7 34.4 35.2

500

10.0

10.0

9.5

9.4

500

11.0

11.0

10.4

10.3

33 Table 3 Properties of bio-oil and char from contaminated sawdust (CS) at different temperature and uncontaminated sawdust (UCS) and hexaneextracted contaminated sawdust (HCS) pyrolysed at 500°C Bio-oil properties Water content (wt%) Solids content (wt%) Ash (wt%) pH Density (kg/dm3) HHV of Heavy bio-oil (MJ/kg) LHV of Heavy bio-oil (MJ/kg) Viscosity at 40 °C

Viscosity change (%) Ageing rate Heating value of char

Biomass 400 12.2±0.9 79.1±0.8 0.4±0.1 0.1±0.3 3.4±0.1 2.7±1.5 0.9±0.0 30.2±0.5 34.4±0.5 28.4±0.5 32.6±0.5

450 4.3±0.1 79.7±0.3 0.4±0.0 0.1±0.0 3.7±0.2 2.6±0.1 0.9±0.0 31.7±0.5 33.2±0.5 29.9±0.5 31.3±0.5

CS 500 3.8±0.1 76.3±1.5 0.4±0.0 0.1±0.0 3.5±0.1 2.8±0.1 0.9±0.0 31.5±0.5 32.8±0.5 29.7±0.5 30.9±0.5

82.2±0.5 72.7±0.5

192.6±0.5 170.3±0.5

219±0.5 191.3±0.5

228.7±0.5 190.6±0.5

182.5±0.5 158.8±0.5

18.2±0.5 21.7±0.5

98.4±0.5 115.6±0.5

125 max 150 max

125 max 150 max

Kinematic (cSt/h) Dynamic (cP/h)

108.7±0.5 96.1±0.5 32.2±0.5 0.98±0.02 1.10±0.02

265.6±0.5 234.8±0.5 37.9±0.5 2.69±0.02 3.04±0.02

294.4±0.5 257.2±0.5 34.4±0.5 2.75±0.02 3.14±0.02

306.6±0.5 255.4±0.5 34±0.5 2.70±0.02 3.24±0.02

253.0±0.5 220.2±0.5 38.7±0.5 2.56±0.02 2.94±0.02

28.2±0.5 33.6±0.5 54.7±0.5 0.49±0.02 0.42±0.02

138.3±0.5 162.4±0.5 40.6±0.5 1.95±0.02 1.66±0.02

125 max 150 max N/A N/A N/A

125 max 150 max N/A N/A N/A

HHV (MJ/kg) LHV (MJ/kg)

18.4±0.5 17.6±0.5

18.4±0.5 17.7±0.5

18.5±0.5 17.7±0.5

18.6±0.5 17.8±0.5

18.6±0.5 17.8±0.5

24.4±0.5 23.5±0.5

18.6±0.5 17.8±0.5

N/A N/A

N/A N/A

Pyrolysis temperatures (C) Heavy bio-oil Light bio-oil Heavy bio-oil Heavy bio-oil Heavy bio-oil Light bio-oil Heavy bio-oil Wet basis Dry basis Wet basis Dry basis Fresh heavy bio-oil Kinematic (cSt, mm2/s) Dynamic (cP, mPa.s) Aged heavy bio-oil Kinematic (cSt, mm2/s) Dynamic (cP, mPa.s)

*Grade G pyrolysis liquid biofuel is intended for use in industrial burners and commercial/industrial burners requiring lower solids and ash content

550 3.8±0.6 78.8±0.2 0.5±0.0 0.1±0.0 3.7±0.1 2.8±0.1 0.8±0.0 31.4±0.5 32.6±0.5 29.6±0.5 30.8±0.5

600 4.6±0.2 77.5±0.8 0.4±0.0 0.1±0.0 3.5±0.1 2.7±0.1 0.9±0.0 31.5±0.5 33.0±0.5 29.7±0.5 31.2±0.5

UCS 500 22.8±0.8 87.8±0.9 0.4±0.0 0.1±0.0 3.7±0.1 2.8±0.1 1.2±0.0 23.9±0.5 30.9±0.5 22.2±0.5 29.5±0.5

HCS 500 9.8±0.4 77.8±0.5 0.5±0.0 0.1±0.0 3.5±0.5 2.7±0.1 1.2±0.0 26.8±0.5 29.7±0.5 25.3±0.5 28.4±0.5

ASTM D7544-12* [33] Grade G Grade D 30 max 30 max N/A N/A 2.5 max 0.25 max 0.25 max 0.15 max Report Report N/A N/A 1.1–1.3 1.1–1.3 15 min 15 min 21 min 21 min N/A N/A N/A N/A

Grade D pyrolysis liquid is intended for use in

34 Table 4 Major chemicals in CS, UCS and HCS heavy bio-oils identified by GC/MS Retention time (min) 2.37 2.62 2.77 3.07 3.52 3.91 4.08 4.51 5.06 5.13 5.25 6.14 6.20 6.67 7.07 7.83 8.26 9.46 9.55 9.59 9.68 12.49 12.93 13.23 13.41 13.49 14.40 15.13 16.83 17.76 17.77 18.09 19.29 19.36 20.93 21.25 21.37 21.54 21.57 22.18 22.65 24.38 24.91 25.26 25.37 26.00 27.05 31.06 38.69 39.43 39.83 40.60 41.33 41.72 42.07 43.16 44.14 44.56 45.91 48.94

Compound name Propane 2-Butanone Propanal Diethoxymethyl acetate 2-Furancarboxaldehyde Butanal 2-Propanone Tetrahydrofuran-5-on-2-methanol 2(5H)-Furanone 2-Cyclohexen-1-ol 1,2-Cyclopentanedione Propanoic acid 2-Furancarboxaldehyde Phenol 3-Cyclobutene-1,2-dione, 3,4-dihydroxy 1,2-Cyclopentanedione, 3-methyl 3,4-Octanedione 2,5-Dimethyl-4-hydroxy-3(2H)-furanone 1-Dodecene Phenol, 2-methoxy Cyclopropyl carbinol Phenol, 2-methoxy-4-methyl 2-Propenoic acid 1-Butanol, 4-butoxy Guanosine, 2'-deoxy 2-Furancarboxaldehyde, 5-(hydroxymethyl) 1,2-Benzenediol, 3-methoxy 1-Pentadecene Phenol, 2,6-dimethoxy 9-Octadecene 1,2,3-Benzenetriol Benzaldehyde, 3-hydroxy-4-methoxy 1,2,4-Trimethoxybenzene Phenol, 2-methoxy-4-(1-propenyl) Levoglucosan Benzene, 1,2,3-trimethoxy-5-methyl 2-Propanone, 1-(4-hydroxy-3-methoxyphenyl) Methyl 3-O-acetylpentopyranoside Pentanoic acid, 4-oxo4-Methyl-2,5-dimethoxybenzaldehyde 9-Eicosene Benzaldehyde, 4-hydroxy-3,5-dimethoxy 1-Octadecene Phenol, 2,6-dimethoxy-4-(2-propenyl) 3,5-Dimethoxy-4-hydroxyphenylacetic acid Ethanone, 1-(4-hydroxy-3,5-dimethoxyphenyl) 1-Nonadecene 3,5-Dimethoxy-4-hydroxycinnamaldehyde Hentriacontane 17-Pentatriacontene Hentriacontane Pentatriacontane Tricosane Tetracontane Tetratetracontane Triacontane Hexacosane Pentatriacontane Hexacosane,13-dodecyl Phenanthrene

Formula C7H16O2 C6H10O3 C3 H6O C7H14O4 C5H4O2 C6H12O C5H8O3 C11H16O7 C4H4O2 C6 H10O C5H6O2 C5H8O2 C6H6O2 C6H6O C4H2O4 C6H8O2 C8H14O2 C6H8O3 C12H24 C7H8O2 C4H8O C8H10O2 C6H10O2 C8H18O2 C10H13N5O4 C6H6O3 C7H8O3 C15H30 C8H10O3 C18H36 C6H6O3 C8H8O3 C9H12O3 C10H12O2 C6H10O5 C10H14O3 C10H12O3 C8H14O6 C5H8O3 C10H12O3 C20H40 C9H10O4 C18H36 C11H14O3 C10H12O5 C10H12O4 C19H38 C11H12O4 C31H64 C35H70 C31H64 C35H72 C23H48 C40H82 C44H90 C30H62 C26H54 C35H72 C38H78 C26H48 Total area (%)

Chromotographic Peak Area (%) CS 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.30 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.47 0.00 6.82 0.00 0.00 0.00 1.48 0.00 0.00 0.00 0.00 0.00 0.00 1.24 0.00 0.99 0.00 0.00 0.00 0.71 0.00 3.09 1.33 5.81 3.07 4.24 9.11 6.44 13.25 25.24 9.70 1.27 2.44 100

UCS 1.16 2.53 1.93 0.78 2.46 0.68 0.00 1.54 1.47 0.71 1.42 0.00 1.18 0.45 2.10 1.03 0.00 0.51 0.00 1.23 0.00 1.21 0.00 0.00 0.00 2.31 0.61 0.00 3.49 0.00 1.36 1.08 2.73 1.05 52.66 1.36 0.44 0.00 1.00 0.89 0.00 1.21 0.00 3.21 1.97 1.39 0.00 0.84 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100

HCS 1.01 3.56 3.00 1.25 2.56 1.12 0.60 1.17 3.25 0.00 1.15 0.26 0.61 0.62 2.18 1.22 0.83 0.36 0.00 1.01 0.80 1.27 2.06 0.59 0.64 1.35 0.54 0.00 2.88 0.00 0.00 0.43 2.29 0.00 53.81 0.50 0.31 1.20 0.00 0.00 0.00 1.29 0.00 0.81 1.45 1.36 0.00 0.66 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 100