- Email: [email protected]
Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis
Biomass and Bioenergy xxx (2016) 1e11
Contents lists available at ScienceDirect
Biomass and Bioenergy journal homepage: http://www.elsevier.com/locate/biombioe
Research paper
Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis Konstantinos G. Kalogiannis a, *, Stylianos D. Stefanidis a, b, Chrysoula M. Michailof a, Angelos A. Lappas a, ** a b
Chemical Process and Energy Resources Institute, Centre for Research and Technology Hellas, 6th km Harilaou-Thermi road, 57001, Thessaloniki, Greece Department of Mechanical Engineering, University of Western Macedonia, Bakola & Sialvera, 50100, Kozani, Greece
a r t i c l e i n f o
a b s t r a c t
Article history: Received 29 February 2016 Received in revised form 29 June 2016 Accepted 1 July 2016 Available online xxx
Castor oil is a vegetable oil obtained by pressing the seeds of the castor oil plant (Ricinus communis). Its production leads to high volumes of solid residues, the castor bean cakes. The main objective of this study was to investigate the potential of these castor bean cakes as a valuable source for production of high added value products such as bio-fuels and renewable chemicals. The upgrading of the castor bean cakes was attempted via thermochemical processes; specifically fast thermal and catalytic pyrolysis. Initially thermal pyrolysis of two different castor cakes and one type of castor stalks took place in a fixed bed fast pyrolysis reactor. The best feed was chosen for catalytic pyrolysis testing where industrially available microporous and one mesoporous catalyst were studied. Mass balances and products characterization via elemental analysis and two dimensional gas chromatography coupled to time-of-flight mass spectrometry (GCxGC-TOFMS) in the case of the liquid products allowed for the estimation of the catalytic effect in each case. © 2016 Published by Elsevier Ltd.
Keywords: Castor bean cake Biomass pyrolysis ZSM-5 Catalytic upgrading GCxGC-ToFMS
1. Introduction Castor (Ricinus Communis L.) is an oilseed crop containing a very high oil mass fraction ranging from 42 to 58% of the seeds weight. The castor oil is not used for edible purposes as it contains ricinoleic acid, a monounsaturated hydroxy 18-carbon fatty acid at 84e90% of its total fatty acid mass fraction [1]. Among fatty acids, ricinoleic acid is unusual in that it has a hydroxyl functional group on the 12th carbon. This functional group causes ricinoleic acid (and castor oil) to be more polar than most fats. The chemical reactivity of the alcohol group also allows chemical derivatization that is not possible with most other seed oils. Because of its ricinoleic acid mass fraction, castor oil is a valuable feedstock, commanding a higher price than other seed oils. Castor oil and its derivatives are used in the manufacturing of soaps, lubricants, hydraulic and brake fluids, paints, dyes, coatings, inks, cold resistant plastics, waxes and polishes, nylon, pharmaceuticals and perfumes [2]. In 2013, a total of 681,000 tonnes of castor oil was produced
* Corresponding author. ** Corresponding author. E-mail addresses: [email protected] (K.G. Kalogiannis), [email protected]. gr (A.A. Lappas).
globally with India production accounting for more than 81% of the total world production. The castor oil prices for 2013 were more than 1600 $ t1. However, the castor oil production is accompanied by high volumes of byeproducts such as the extracted castor cakes or the residues of the plant (e.g. leaves, stems etc.) that may amount up to quantities equal or higher than the oil itself thereby affecting the economics of the total castor production [3,4]. In addition, the castor cake contains significant amounts of allergens and ricin, a protein with toxicity for humans and animals, while the stems and residual plant parts contain alkaloids and in particular ricinine, which is also toxic for humans and animals. Evidently, these factors limit the uses of the by-products to certain applications such as their use as fertilizer, while the castor cakes might also be used for animal feed but only after detoxification treatments [5]. Consequently, alternative processes for the utilization and valorization of castor cake, stalks etc. are required. On the other hand, renewable energy has been the focus of research efforts in the past years due to the increasing world energy demand, finite oil/natural gas reserves and concerns over energy security and the protection of the environment. This has strongly motivated our society to search for alternative energy sources and specifically liquid transportation fuels [6e8]. Biomass is an abundant renewable carbon source that can help mitigate the
http://dx.doi.org/10.1016/j.biombioe.2016.07.001 0961-9534/© 2016 Published by Elsevier Ltd.
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
2
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
dependence on fossil fuels and the emission of greenhouse gases, via its conversion to gaseous, liquid and solid energy carriers through thermochemical processes (i.e. fast and/or slow pyrolysis, gasification etc.). Biomass fast pyrolysis is a very interesting technology for the production of liquid oil (bio-oil), which is considered to be a very promising biofuel/bioenergy carrier and a source of renewable high added value chemicals. Bio-oil is a complex mixture of oxygenated compounds originating from the thermal decomposition of the cellulose, hemicellulose and lignin, the main constituents of lignocellulosic biomass [9e13]. The acids, ketones, aldehydes and other oxygenates in the bio-oil are responsible for a series of undesirable properties, such as low calorific value, corrosiveness, instability under storage and transportation conditions, immiscibility with hydrocarbon fuels and high viscosity [14]. In order to upgrade the low quality bio-oil produced by thermal pyrolysis, heterogeneous catalysts are employed [15e17]. The pyrolysis vapors come in contact with a solid catalyst and are cracked, deoxygenated and selectively converted to more desirable compounds, such as aromatic hydrocarbons and simpler phenols. This results in a lighter bio-oil with improved properties and higher calorific mass fraction. Oxygen is removed in the form of gas CO2 and CO and by the formation of H2O. The application of fast pyrolysis presents an interesting alternative for the valorization of by-products from the castor oil production, however to the best of the authors’ knowledge it has been scarcely reported in the literature. Among the few dedicated publications is one from Aldobouni et al. [18] who pyrolyzed castor bean cakes for production of bio-oil and carbon adsorbents from the residual pyrolysis char, while Santos et al. studied the kinetics of castor bean presscake pyrolysis [19]. This work presents the thermal and catalytic fast pyrolysis of castor cakes and stalks from castor plants cultivated in Southern Greece during 2013. Four commercially available catalysts have been studied for their effect on the pyrolysis products. Much emphasis has been placed on the analysis of the bio-oils by GCxGC-ToFMS in order to clarify the composition of the bio-oils and elucidate the effect of the catalysts.
2. Materials and methods 2.1. Biomass samples and characterization Three biomass samples were used in this study; two castor bean cakes (castor cake #1 and castor cake #2) and a sample of castor stalks. Carbon, hydrogen and nitrogen mass fractions in the biomass samples were determined by a CHN LECO-800 elemental analyzer from Leco Corporation (USA). Oxygen mass fraction was determined by difference. The moisture mass fraction was measured by drying a pre-weighed sample at 105 C for 4 h. The total ash mass fraction was measured by combustion of 2 g of sample in a muffle furnace at 600 C for 16 h. Inductive coupled plasma-atomic emission spectroscopy (ICP-AES) was used for the determination of the inorganic mass fraction of the biomass samples, utilizing a Perkin Elmer Plasma 400 spectrometer. The hemicellulose, cellulose and lignin mass fraction were determined according to the well-known NREL methods (NREL/TP-510-42618 [20] and NREL/TP-510-42619 [21]). Finally the protein mass fraction was measured according to the N-Kjeldahl method (AOAC 955.04). For further information regarding the initial castor plants the reader is kindly referred to the work by Merkouropoulos et al. [22] where castor cake #1, castor cake#2 originated from the hybrids H11 and H14 respectively while the castor stalks used in this work were those from the H14 variant.
2.2. Catalysts For thermal pyrolysis silica sand was used that acted as inert material. The silica sand had particle size ranging between 90 and 500 mm, near zero specific surface area, due to the zero internal porosity of silica sand particles, and no acidity nor basicity. It was therefore a fully inert material with no catalytic effect that served as the base case material for testing different feedstocks and pyrolysis temperatures. N2 adsorption-desorption experiments at 196 C were performed on an Automatic Volumetric Sorption Analyzer (Autosorb-1, Quantachrome) for the determination of surface area (BET method), total pore volume at P/Po ¼ 0.99, micropore volume (t-plot method), and pore size distribution (BJH method) of the samples that were previously outgassed at 150 C for 16 h under vacuum at 5 109 Torr. For catalytic pyrolysis commercially available catalysts were used which are presented in Table 1. It should be noted that all the catalysts were fluidizable and in a microparticle formulation. Their average size ranged between 60 and 90 mm, which is typical of the commercially available catalysts. The ZSM-5 catalyst labeled ZSM-5, along with its Co-doped variant, labeled Co-ZSM-5, had 30% by mass of the ZSM-5 zeolite on a silicaalumina matrix with a Si to Al mass ratio of 20. The FCC catalyst was itself a USY zeolite on a silica-alumina matrix. All the above catalysts were microporous, in contrast to the Al-MCM-41 catalyst that was a mesoporous acidic material. 2.3. Description of bench scale biomass fast pyrolysis unit and experimental procedures and conditions 2.3.1. Description of bench scale biomass fast pyrolysis unit All pyrolysis experiments were performed at 500 C and 600 C, using a bench-scale fixed bed reactor, made of stainless steel 316 and heated by a 3-zone furnace. The temperature of each zone was independently controlled using temperature controllers. The catalyst bed temperature was used as the experiment temperature and this was monitored with a thermowell. A specially designed piston system was used to introduce the biomass feedstock into the reactor. A constant stream of N2 was fed from the top of the reactor for the continuous withdrawal of the products and maintenance of the inert atmosphere during pyrolysis. The products exited from the bottom of the reactor in gaseous form and were condensed in a glass receiver submerged in a cooling bath kept at 17 C. Noncondensable gases were collected in a gas collection system. A filter placed between the glass receiver and the gas collection system recovered any condensable gases that were not condensed in the receiver. A schematic diagram of the experimental set-up is given in Fig. 1. Further details may be found elsewhere [15]. 2.3.2. Pyrolysis process and products collection The reactor was filled with 0.7 g catalyst or silica sand for the catalytic and non-catalytic tests respectively and the piston was filled with 1.5 g of biomass. As soon as the desired temperature was reached, the biomass was introduced into the reactor and the experiment began using 100 cm3 min1 nitrogen flow. At the end of the experiment (15 min), the reactor was cooled and purged for 10 min with N2 (50 cm3 min1). For all tests the reactor temperature was kept constant at the selected temperature. The catalyst bed dimensions depend on the catalyst’s apparent bulk density. Residence times depend on catalyst bed height, catalyst bed void fraction and cracked gases volume. A typical residence time of the vapor phase in the bed was 31 ms (calculated for the FCC catalyst). The above described catalytic pyrolysis experiments are of the “exbed” type, i.e. there is no mixing of the solid biomass with the solid catalyst or silica sand.
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
3
Table 1 Catalyst properties employed in this study. Catalyst
Surface area (m2 g1)
Mean pore diameter (1010 m)
Microporosity (cm3 g1)
Mesoporosity (cm3 g1)
Silica sand ZSM-5 Co-ZSM-5 FCC Al-MCM-41
0 138 131 176 337
e 40 36 6 e
e 0.037 0.036 0.035 e
e 0.071 0.082 0.242 e
Fig. 1. Schematic view of CPERI bench scale fixed bed biomass pyrolysis unit.
The liquid products were collected and quantitatively measured in the pre-weighted glass receiver. The pyrolytic vapors, upon their condensation in the glass receiver, formed multiple phases; an aqueous phase, a liquid organic phase and viscous organic deposits on the receiver walls. A method for collecting a representative biooil sample for analysis is described elsewhere [15]. The gas products were collected and measured by the water displacement method and the amount of the solid residue formed was measured by direct weighing. The solid products consisted of charcoal (biomass residue) and coke-on-catalyst formed by thermal and catalytic cracking, as well as a very small amount of unreacted biomass. The unreacted biomass was subtracted from all mass balance calculations. The amount of condensable vapors recovered in the filter was also measured by direct weighing and was added to the liquid products yield. Three experiments under the same conditions were run for each catalytic material in order to ensure repeatability and the average values from the three experimental runs were used.
2.3.3. Methods for pyrolysis gases and bio-oil analysis The water mass fraction of the bio-oil was determined by the Karl-Fischer method (ASTM E203-08) and the carbon, hydrogen and nitrogen mass fraction was determined with an elemental CHN
LECO-800 analyzer. The gaseous products were qualitatively and quantitatively analysed on a HP 5890 Series II gas chromatograph, equipped with four columns (Precolumn: OV-101; Columns: Porapak N, Molecular Sieve 5A and Rt-Qplot (30 m 0.53 mm ID) and two detectors (TCD and FID). Gas products consisted of CO, CO2, CH4, H2 and hydrocarbons with up to 6 carbon atoms.
2.3.4. GCxGC-ToFMS bio-oil characterization Qualitative and quantitative analysis of the bio-oils was performed by means of GCxGC-ToFMS. The analytical system employed consisted of an Agilent 7890A gas chromatograph with an Agilent 7683B series (Agilent Technologies, Palo Alto, CA, USA) injector connected to a Pegasus 4D time-of-flight mass spectrometer from Leco Instruments (St. Joseph, MI, USA). The samples for the GCxGC-ToFMS analysis were prepared from a separate pyrolysis experiment, where the sample collection from the receiver was performed by addition of a weighed amount of MeOH. The samples were further appropriately diluted in MeOH prior to injection, without any other pretreatment. The analysis of the samples was both qualitative and quantitative and further details regarding the chromatographic method employed have been previously reported in detail [23].
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
4
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
3. Results and discussion 3.1. Characterization of biomass samples Characterization of the three feedstocks used in this study is presented in Table 2. Elemental analysis showed that the castor bean cakes have lower oxygen mass fraction compared to more typical biomass such as the castor stalks, but they have significantly higher N-mass fraction, due to their alkaloid and protein concentration [24]. Additionally, ICP analysis (Table 2) showed very high mass fraction of some alkali metals, specifically Potassium (K), Magnesium (Mg), Calcium (Ca) and in the case of the castor bean cakes Phosphorus (P) as well. Finally, the extractives, lignin, cellulose, hemicellulose and proteins mass fraction is presented for all feeds. The castor bean cakes differ significantly to the castor stalks. They have very low cellulose and hemicellulose mass fraction but an increased extractives mass fraction. The extractives represent the non-structural components of biomass and include waxes, inorganic material, nitrogenous material, sugar acids, and nonstructural components [25] and in this particular case, residual castor oil as well. Additionally, castor bean cakes have increased proteins mass fraction. In contrast the castor plant stalks bear higher resemblance to a typical lignocellulosic biomass with low protein and higher cellulose and hemicellulose mass fractions.
3.2. Fast pyrolysis experimental results 3.2.1. Thermal pyrolysis In Table 3 the mass balances of the main products, that is gases, coke, water and bio-oil organic phase are presented. In the case of both castor cake samples, both the organic phase and coke production were higher compared to the castor stalks. Gases and water production on the other hand were lower in the case of the castor cakes. Increasing temperature resulted in enhanced cracking of the bio-oil vapors. This in turn led to an increase in the gases and water production while coke and the bio-oil organic phase yields were reduced, as has been also previously reported [26,27]. Especially in the case of the castor bean cake #2, increasing the reaction temperature led to an increase of the light hydrocarbons
Table 2 Castor bean cakes and stalks elemental, ICP and biomass components analysis on dry feedstock. Elemental analysis (% by mass)
Castor cake#1
Castor cake#2
Castor stalks
C H O N Ash Alkali (% by mass) Al Ca Cu Fe Na Mg Mn K P Zn Component, (% by mass) Extractives Hemicellulose Cellulose Acid insoluble lignin Acid soluble lignin Proteins
50.8 6.8 33.6 3.2 5.6
51.7 7.0 31.5 4.2 5.6
43.2 6.1 44.7 1.6 4.4
0.002 0.366 0.002 0.008 0.059 0.511 0.002 1.230 1.070 0.009
0.003 0.290 0.002 0.007 0.077 0.485 0.002 1.352 1.053 0.008
0.0112 0.896 0.001 0.006 0.039 0.131 0.001 0.624 0.221 0.002
29.5 4.4 3.8 29.3 5.1 23.0
29.4 5.2 3.5 33.0 4.5 23.1
18.6 13.6 33.4 17.6 2.5 4.9
yields, C1eC6 as can be seen in Table 4. The secondary decomposition of char at higher temperatures has also been found to produce some gaseous products, increasing the overall gas yield [28]. Interestingly enough, the castor cakes produced better quality bio-oils with significantly lower oxygen mass fraction compared to the castor stalks (Table 3), assumingly due to the presence of residual oil in the cake. This was confirmed by the significantly higher CO2 yield, compared to CO yield from castor stalks, which could be attributed to decarboxylation reactions of the fatty acids of residual castor oils. However, increasing the reaction temperature had an adverse effect for the castor cakes. The bio-oil yield was decreased as noted above, but also the bio-oil quality worsened since its oxygen mass fraction increased, in particular in the case of the castor cake #2. The increase of the oxygen mass fraction is attributed to the overcracking of the bio-oil vapors. Essentially, more light hydrocarbons were formed, which were received as gases that reduced the carbon available in the bio-oil. This is not typical of lignocellulosic biomass as can be seen in the case of the high temperature pyrolysis of the castor stalks. In the case of the castor stalks, increasing the reaction temperature led to the expected decrease in the bio-oil yield, accompanied by a slight decrease of the bio-oil’s oxygen mass fraction due to enhanced deoxygenation. These findings are graphically represented in Fig. 2 where bio-oil yield is presented versus the oxygen mass fraction of the bio-oil. In addition, comparing the two castor bean cakes, it appears that castor bean cake #2 resulted in slightly higher bio-oil yield with a lower oxygen mass fraction. Taking these into account, it was decided to test catalytic pyrolysis at 500 C and with the castor bean cake #2. The composition of the three thermal bio-oils was elucidated by GCxGC-ToFMS analysis. The qualitative identification of the compounds was based mainly on the match of the spectra with those of the official library NIST05, considering as minimum identification criteria S/N at 50 and similarity value at 700. Borderline group-type classification was employed for the determination of the specific elution areas of the different classes of compounds on the chromatogram. In total 7 groups were clearly defined in the chromatographic space: 1. Acids and esters, 2. Aldehydes and ketones (including furanoics and cyclic carbonyl compounds), 3. Hydrocarbons (non-aromatic saturated and unsaturated hydrocarbons), 4. Aromatic hydrocarbons, 5. Phenolic compounds (including guaiacols, syringols, anisols and catechols), 6. Long-chain organic acids and 7. Sugars [29]. Fig. 3 presents the chromatograms of castor cake #2 and castor stalks bio-oil. The chromatogram of castor cake #1 bio-oil was the same as that of castor cake #2 bio-oil and therefore it is not presented. By comparing the peak density in each area of the chromatogram, it is possible to get a primary rough estimation of the differences the samples might present. More than 400 peaks were detected in the castor cake bio-oils and 281 in the castor stalk bio-oil. The total number of unidentified peaks in each chromatogram was very small. It is worth pointing out that the major part of the detected bio-oil’s chromatogram area (>1%) is attributed to less than 20 peaks (Table 5). However, for a better representation of the compounds distribution over the chromatographic area, the individual peaks were assigned to groups, and the summation of their relative area % is presented in Fig. 4. The relative area % peaks distribution of the castor cake bio-oils indicate that it is rich in organic acids (mainly long chain) [30] and phenolic derivatives. The main peak in the chromatogram (Fig. 3a) corresponds to undecylenic acid and represents almost 20% of total chromatographic area. Undecylenic acid, along with heptanal, are formed as a result of the thermal decomposition of ricinoleic acid at temperatures higher than 300 C [31,32]. Furthermore, the decomposition of the residual oil of the castor cakes results in the
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
5
Table 3 Thermal pyrolysis mass balances and dry bio-oil elemental composition. Feedstock þ pyrolysis temperature
Castor Castor Castor Castor Castor a
Cake#1 þ 500 C Cake#2 þ 500 C stalks þ500 C Cake#2 þ 600 C stalks þ600 C
Yields, % by mass on dry feedstock
Bio-oil organic phase, % by mass
Bio-oil
Water
Organics
Gas
Coke
C
H
N
Oa
52.5 52.4 56.3 46.9 48.9
18.8 18.0 29.5 20.5 26.8
33.7 34.4 26.8 26.5 22.1
12.4 13.0 19.1 22.6 27.3
35.1 34.6 24.6 30.5 23.8
63.4 64.0 58.0 59.9 58.8
10.1 10.2 7.7 9.6 7.7
9.9 9.5 0.6 10.1 0.4
16.6 16.3 33.7 20.4 33.1
Oxygen mass fraction is calculated by difference.
Table 4 Thermal pyrolysis gases on dry feedstock. Feedstock þ pyrolysis temperature
Castor Castor Castor Castor Castor
Cake#1 þ 500 C Cake#2 þ 500 C stalks þ500 C Cake#2 þ 600 C stalks þ600 C
Individual gas yields, % by mass on dry feedstock CO2
CO
H2
CH4
C2H6
C2H4
C3H8
C3H6
C4eC6
8.5 9.2 12.7 10.2 14.7
2.1 2.1 4.9 4.4 8.8
0.0 0.0 0.0 0.1 0.2
0.3 0.3 0.6 1.5 1.8
0.3 0.3 0.2 0.8 0.4
0.2 0.2 0.1 2.0 0.4
0.2 0.1 0.1 0.3 0.1
0.2 0.3 0.1 1.6 0.3
0.6 0.5 0.4 1.7 0.6
Fig. 2. Thermal pyrolysis bio-oil yield vs bio-oil oxygen mass fraction.
formation of saturated and unsaturated hydrocarbons [33] with Cchain length between C9 to C20, as indicated by the peaks in the respective area. Additionally, the castor cake bio-oils contain a significant number of N-compounds, due to the thermal decomposition of the proteins in the castor cakes. In particular, proteins produce large amounts of nitrogen heterocycles, pyrroles, and indoles [33]. However, these compounds are distributed throughout the chromatogram and co-eluted in the areas of the oxygenated compounds with similar structure (i.e. pyrrole and its derivatives are eluted in the aldehydes and ketones area along with furans) therefore they could not be separated as a specific group. The Ncompounds identified are mainly pyrrole, pyridine and amide derivatives, with amides and pyrroles being the prevailing groups. Similar results pertaining the groups of compounds in the castor cake bio-oils were presented in the work of Silva et al. [34], however the distribution of the groups is different due to the different
Fig. 3. GCxGC-ToFMS chromatograms of (a) castor cake #2 bio-oil (b) castor stalk bio-oil (the chromatogram of castor cake #1 bio-oil is the same as that of castor cake #2 bio-oil and therefore is not presented here).
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
6
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
Table 5 Distribution of peaks based on relative peak area and number of total, unidentified and quantified peaks (numbers in parentheses correspond to total peak area). Sample
Total peaks
Castor 405 cake#1 Castor 461 cake#2 Castor 281 stalks
Unidentified peaks
No. of peaks with rel. Area >1%
No. of peaks with rel. Area >0.5%
No. of peaks with rel. Area >0.3%
No. of peaks with rel. Area >0.1%
%Area quantified
No. of quantified peaks
78 (3.4%)
16 (61.9%)
26 (68.7%)
48 (77.6%)
114 (89.0%)
31.2
32
60 (2.9%)
16 (61.9%)
29 (69.9%)
48 (77.6%)
110 (88.1%)
29.4
34
27 (0.6%)
18 (70.2%)
33 (80.7%)
45 (85.01%)
96 (93.6%)
83.7
104
Fig. 4. Distribution of groups detected in the thermal bio-oils based on their relative area % (AR: aromatic hydrocarbons, ALI: aliphatic hydrocarbons, PH: phenolic compounds, FUR: furanic compounds, AC: organic acids, EST: esters, AL: alcohols, ETH: ethers, ALD: aldehydes, KET: ketones, PAH: polyaromatic hydrocarbons, SUG: sugars, NIT: N-compounds, UN:unidentified).
production conditions (slow pyrolysis at 380 C). In the case of castor stalks bio-oil, its chromatographic profile (Fig. 3b) is similar to that resulting from conventional woody biomasses. It contains primarily phenolic compounds, mainly due to the decomposition of lignin, along with carbonyl compounds (i.e. furfural and cyclopentanones) due to the cellulose and hemicellulose decomposition. The prevailing peak in the chromatogram is that of acetic acid (in the acids area at the beginning of the chromatogram), which represents almost 40% of the total chromatographic space. Neither long-chain organic acids nor hydrocarbons are detected. However, due to the small protein mass fraction of the
stalks (4.9% by mass) some N-compounds are detected, mainly cyclic 5 and 6-membered compounds. A GCxGC-ToFMS quantification method for bio-oils originating from lignocellulosic biomass has been previously developed and applied for the analysis of bio-oils of different origin [23,29,35]. This method has been applied in this case as well, however since it does not include N-compounds neither long-chain organic acids, only a very small percentage of the castor cake bio-oil was estimated quantitatively (5.3 and 4.1% mass fraction of the organic phase of the bio-oil). In both cases, the main compounds identified were acetic acid (3.2 and 2.4% by mass respectively), catechol and methyl
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
catechols. It should be noted that acetic acid which is a typical component of the thermal bio-oils, was detected at very low concentration in this case, due to the very low mass fraction of cellulose and hemicellulose in the original biomass. On the contrary, the castor stalk bio-oil composition is quantified to a greater extent. In particular, 10.2% by mass of the organic phase of the castor stalks bio-oil is attributed to organic acids (mainly acetic acid), 8% by mass is attributed to phenolic compounds (syringol and 1,2-benzendiol are the main components), while 9.4% by mass corresponds to total carbonyl compounds (30 ,50 -Dimethoxyacetophenone, furfural, furanone and cyclopentanone derivatives are the main components).
3.2.2. Catalytic pyrolysis The ZSM-5 and FCC catalysts are industrially available catalysts while the Co-ZSM-5 is the industrially available catalyst impregnated with 5% by mass Co by the wet impregnation method which can be found elsewhere [36]. The experimental results of catalytic pyrolysis of castor cake #2 are presented in Tables 6 and 7. In Table 6 the mass balances of the main products, that is gases, coke, water and bio-oil organic phase are presented. The elemental analysis of the derived organic phases of the bio-oils is also presented in Table 6. The individual gases yields when the various catalysts were applied are presented in Table 7. In all cases the in situ catalytic upgrading leads to increase in the water yield, gases and coke, while the bio-oil yield is decreased. The use of catalysis increased gases production, especially the light hydrocarbons, in part due to further cracking of some of the residual castor oil towards lower MW products such as C4eC6. The Co doped ZSM-5 and the FCC catalysts had a milder effect while the ZSM-5 and the Al-MCM-41 mesoporous catalyst appear to be the most active materials, producing the least bio-oil. A significant difference was noted between these two materials. The ZSM-5 catalyst did not increase coke production, while the Al-MCM-41 increased coke production significantly. Table 6 presents the C measured on the silica sand particles and the various catalysts. The C on the catalyst is catalytically produced coke due to the conversion reactions taking place when the bio-oil vapors come into contact with the catalyst. The ZSM-5 catalyst, known for its shape selectivity and two dimensional pore structure, did not significantly increase coke production (only ~ 2% by mass C on catalyst was measured). The Al-MCM-41 on the other hand, allowed condensation reactions to continue on its large mesopores leading to polyaromatics and increased coke production. The Co-ZSM-5 and the FCC catalysts produced more coke but still quite lower compared to the mesoporous Al-MCM-41. In Table 6 the elemental analysis of the produced bio-oils is presented on a dry basis. The ZSM-5 catalyst produced the most deoxygenated bio-oil with an oxygen mass fraction of less than 7%. In addition, the N-mass fraction of the bio-oil also decreased which is a further positive effect. The Al-MCM-41 catalyst on the other hand barely deoxygenated the bio-oil, although it sacrificed a significant part of the
7
Table 7 Catalytic pyrolysis gases on dry feedstock. Catalyst
Silica sand ZSM-5 Al-MCM-41 Co/ZSM-5 FCC
Individual gas yields, % by mass on dry feedstock CO2
CO
H2
CH4
C2H6
C2H4
C3H8
C3H6
C4eC6
9.2 8.6 9.1 8.9 8.8
2.1 2.6 2.4 2.6 2.3
0 0 0 0.1 0
0.3 0.4 0.5 0.3 0.4
0.3 0.3 0.5 0.3 0.4
0.2 0.4 0.3 0.4 0.3
0.1 0.2 0.3 0.2 0.3
0.3 0.7 0.4 0.7 0.4
0.5 1.5 1.2 1.1 1
bio-oil yield. This adverse effect was attributed to the mesoporosity of the material. The large mesopores allowed for condensation reactions to continue uncontrolled, leading to the transformation of aromatic compounds to polyaromatic and then to coke. This resulted in increased carbon losses towards the solid coke product which in turn meant that less carbon was available for the liquid product. This effect has also been reported by other researchers. They found that pore enlargements led to higher molecular weight products [37]. Adam et al. studied four different Al-MCM-41 materials and found that PAHs yield increased significantly while pore size enlargement had a deteriorating effect on the bio-oil quality [38]. Antonakou et al. made similar observations studying Al-MCM41 materials with different Si/Al ratios, where it was found that biooil yield decreased while coke production increased significantly [39]. Jackson et al. also compared a ZSM-5 zeolite to a mesoporous Al-MCM-41 for the upgrading of lignin pyrolysis vapors and observed that the AlMCM-41 catalyst behaved similarly to the ZSM5, although it was not as effective at deoxygenating the liquid phase and gave more naphthalenics than simple aromatics [40]. In our work, the ZSM-5 catalyst, which features a very well defined microporous structure, minimized condensation reactions, managing to keep the carbon in the liquid product, hence the increased process efficiency. Fig. 5 presents the above findings schematically, where bio-oil yield is presented vs the bio-oil oxygen mass fraction. The catalytic bio-oils were further analysed by GCxGC-ToFMS.
Fig. 5. Catalytic pyrolysis bio-oil yield vs bio-oil oxygen mass fraction.
Table 6 Catalytic pyrolysis mass balances and dry bio-oil elemental composition. Catalyst
Silica sand ZSM-5 Al-MCM-41 Co/ZSM-5 FCC
Yields, % by mass on dry feedstock
C on cat.
Bio-oil
Water
Organics
Gas
Coke
52.4 52.8 48.8 52.2 52.4
18.0 26.1 23.3 21.1 22.0
34.4 26.7 25.5 31.1 30.4
13.0 14.7 14.7 14.6 13.9
34.6 32.5 36.5 33.2 33.7
0.16 1.98 9.48 3.54 3.59
Bio-oil organic phase, % by mass on dry oil C (ORG)
H (ORG)
N (ORG)
O (ORG)
64.0 75.3 65.2 66.7 69.8
10.2 9.8 10.3 10.3 10.1
9.5 8.1 8.8 9.5 11.3
16.3 6.8 15.7 13.5 8.8
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
8
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
The respective chromatograms are presented in Fig. 6 while in Table 8 the total number of detected peaks is presented. The number of peaks in the catalytic bio-oils is almost twice that detected in the thermal bio-oils, indicating the extensive cracking of the biomasses to smaller compounds. The graphic representation of the peaks distribution in the assigned groups, based on their relative area % is presented in Fig. 7. The catalysts selected had a marked effect on the composition of the bio-oils compared to the thermal castor cake bio-oil, as there is an increase in the hydrocarbons (both non-aromatic and aromatic) mass fraction and a decrease in the phenolics and acids mass fraction. In particular, the catalysts increased the aromatics mass fraction in the order ZSM-5 > Co-ZSM-5 > FCC > Al-MCM-41. The respective quantitative analysis revealed that the aromatics concentration was 1.85 > 1.06>0.91 > 0.87% by mass of the organic phase of the bio-oils (the respective concentration for the thermal castor cake #2 bio-oil was 0.05% by mass) and was attributed
mainly to toluene, benzene and alkyl-benzenes. The bio-oil from the thermal pyrolysis of castor cake contains few non-aromatic hydrocarbons, and in particular olefins, possibly due to the thermal decomposition of the residual oil (Fig. 4). The addition of catalysts not only increased the non-aromatic hydrocarbons mass fraction but also had an effect on the type of hydrocarbons produced. The non-aromatic hydrocarbons mass fraction in the catalytic bio-oils decreased in the order Al-MCM-41 > FCC > ZSM5>Co-ZSM-5 which corresponds to actual concentration of 3.21 > 2.51>1.94 > 1.19% by mass of the organic phase of the bio-oils respectively and in each case was higher than the 0.09% by mass of the thermal bio-oil. In order to clarify the effect of the catalysts, the hydrocarbons peak areas were normalized based on their total area in each sample and were further divided to subgroups of n- and isoparaffins, n- and iso-olefins, as well as saturated and unsaturated naphthenes (Fig. 7). Based on the results, ZSM-5 and Co/ZSM-5 promote the formation of n- and iso-olefins while their tendency
Fig. 6. GCxGC-ToFMS chromatograms of catalytic bio-oils (A) ZSM-5, (B) Co-ZSM-5, (C) FCC, (D) Al-MCM-41.
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
9
Table 8 Distribution of peaks based on relative peak area and number of total, unidentified and quantified peaks (numbers in parenthesis correspond to total peak area). Sample
Total peaks
Unidentified peaks
No. of peaks with rel. Area >1%
No. of peaks with rel. Area No. of peaks with rel. Area No. of peaks with rel. Area %Area >0.5% >0.3% >0.1% quantified
Quantified
ZSM-5 FCC Co-ZSM5 Al_MCM_41
758 683 530 945
64 59 52 69
19 17 19 13
33 35 31 37
271 240 177 331
(3.2%) (1.6%) (1.5%) (1.1%)
(45.9%) (42.2%) (58.5%) (30.7%)
(55.6%) (55.1%) (66.8%) (46.6%)
51 60 45 68
(62.6%) (64.6%) (72.1%) (58.1%)
148 162 124 170
(79.6%) (81.3%) (84.9%) (75.8%)
59.6 53.2 52.9 54.2
Fig. 7. Distribution of groups detected in the catalytic bio-oils based on their relative chromatographic area %.
to form aromatics is reflected by the increase of the naphthenes. The doping of ZSM-5 with Co decreased the overall hydrocarbons produced compared to ZSM-5, but contrary to ZSM-5 it promoted the formation of paraffins. Similar behaviour is demonstrated by the FCC catalyst. Among the catalysts, the highest non-aromatic hydrocarbons mass fraction is produced by the Al-MCM-41 and is distributed mainly between n- and iso-olefins. This was expected
since the Al-MCM-41 material is an amorphous mesoporous material and is therefore suitable for cracking large molecules such as the residual organic acids found in the castor bean cake, towards lower molecular weight products. The shape selectivity of the ZSM5 material on the other hand increased the production of aromatic hydrocarbons. Regarding the phenolics concentration it has been decreased, compared to the respective concentration in the thermal
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
10
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
bio-oil, in the order ZSM-5> Co/ZSM-5> FCC > Al-MCM-41 which corresponds to quantitative concentrations of 3.00 > 2.37>2.12 > 1.45% by mass of the organic phase of the biooils respectively as compared to the 1.37% by mass of the organic phase of the thermal bio-oil. The relative area of the phenolics of the thermal castor cake #2 bio-oil appears higher in Fig. 7, due to the fact that the chromatogram contains fewer peaks than the respective chromatograms of the catalytic bio-oils and consequently the relative area attributed to phenolics is higher. The actual quantitative analysis of the phenolics clarified the difference and highlighted the importance of differentiating between semiquantitative and quantitative results. As far as the acids are concerned, the thermal castor cake #2 bio-oil had a high peak attributed to undecylenic acid (18.8% of the chromatographic area). This peak was significantly lower in the catalytic bio-oils in the order Co-ZSM-5 >ZSM-5 ¼ FCC > Al-MCM-41, however the actual mass fraction of this acid could not be quantified. Nonetheless, the acetic acid mass fraction was determined quantitatively and was found to increase from 2.4% by mass of the organic phase in the thermal biooil to 6.2, 5.9 and 4.8% by mass in Co-ZSM-5, ZSM-5 and FCC bio-oils respectively, while it decreased to 1.8% by mass in the organic phase of the Al-MCM-41 bio-oil. Had there been a separation of the aqueous and organic phase of these bio-oils, most of the acetic acid would have partitioned to the aqueous phase, leaving the organic phase with decreased acidity compared to a thermal bio-oil, but in this case phase separation was not possible due to sample quantity limitations and therefore the total bio-oil was analysed. Finally the N-compounds occupy a significant percent of the chromatographic area and appear recalcitrant to the catalysts, as also indicated by the N-mass fraction of the catalytic bio-oils (Table 6). It appears that due to the catalysts the amides and pyridines are decreased, while the nitriles are increased, an effect most pronounced in the case of Al-MCM-41. The pyrrole derivatives appear unaffected by the catalysts tested. 4. Conclusions This work focused on investigating the thermal and catalytic pyrolysis of castor bean cakes and stalks at different temperatures in a fixed bed unit. Castor bean cakes were found to pyrolyze much more efficiently compared to castor stalks. This was attributed to the residual castor oil in the castor cakes that increased the organic oil yield while allowing for the transformation of the residual castor oil into valuable compounds such as aromatic hydrocarbons. The pyrolysis temperature of 500 C was found to be the most suitable one, since at the higher temperature of 600 C overcracking led to less bio-oil yield with higher oxygen mass fraction reducing the overall process efficiency. This was attributed to overcracking of the bio-oil vapors that resulted in a shift of the available C from the biooil towards gas products, especially light hydrocarbons. Moreover, GCxGC analysis revealed that the thermal oils consisted of organic acids, in particular undecylenic acid, due to the degradation of residual oils in the feed. Due to the high mass fraction of proteins in the castor cakes, a significant number of N- compounds was also detected. In situ catalytic upgrading allowed for the efficient deoxygenation of the castor bean cake bio-oil in a much more efficient manner, yielding a bio-oil with oxygen mass fraction less than 7% in the case of the ZSM-5 catalyst. The ZSM-5 catalyst was also found to decrease the N- mass fraction of the bio-oil. According to the chromatographic analysis ZSM-5 catalyst resulted in the increase of aromatic compounds such as benzene, toluene and xylene. The mesoporous Al-MCM-41 and the FCC catalyst on the other hand produced more aliphatic hydrocarbons but had significant losses of C towards coke production, especially so in the case of the mesoporous material. Overall, the castor cakes were found to
be a very interesting feedstock for the production of pyrolysis biooil, especially so in the case of the in situ catalytic upgrading that produced a higher quality product that could be potentially upgraded towards fuel. Acknowledgements The authors wish to acknowledge funding of this research from the project JONAН-FUEL, “CASTOR bean (JONAH seed) cultivation in central Macedonia, Greece and industrial exploitation of its derivatives towards BIOFUELs’ production”, agreement no. ISR_3176, which is co-funded by Greece and the European Regional Development Fund, under OPCE II and within the program ‘Bilateral R&D cooperation between Greece and Israel 2013e2015’. References ndez-Martínez, Velasco, in: J.M. Ferna ndez-Martínez, L. Velasco Castor, [1] Ferna S.K. Gupta (Eds.), Technological Innovations in Major World Oil Crops, Breeding, vol. 1, Springer, New York, 2012, pp. 237e265. [2] H. Mutlu, M.A.R. Meier, Castor oil as a renewable resource for the chemical industry, Eur J Lipid Sci. Technol. 112 (1) (2010) 10e30. [3] M. Pavaskar, A. Kshirsagar, Global Castor oil and indian monopoly, Financ. Vis. 1 (5) (2013) 15e19. n, Design and analysis of a second and [4] J. Moncada, C.A. Cardona, L.E. Rinco third generation biorefinery: the case of castor bean and microalgae, Bioresour. Technol. 198 (2015) 836e843. [5] L.S. Severino, D.L. Auld, M. Baldanzi, M.J.D. C^ andido, G. Chen, W. Crosby, et al., A review on the challenges for increased production of castor, Agron. J. 104 (4) (2012) 853e880. [6] H.B. Goyal, D. Seal, R.C. Saxena, Bio-fuels from thermochemical conversion of renewable resources: a review, Renew. Sustain. Energy Rev. 12 (2) (2008) 504e517. [7] Y.C. Lin, G.W. Huber, The critical role of heterogeneous catalysis in lignocellulosic biomass conversion, Energy Environ. Sci. 2 (2009) 68e80. [8] G.W. Huber, S. Iborra, A. Corma, Synthesis of transportation fuels from biomass: chemistry, catalysts, and engineering, Chem. Rev. 106 (9) (2006) 4044e4098. [9] A.V. Bridgwater, Review of fast pyrolysis of biomass and product upgrading, Biomass Bioenergy 38 (March) (2012) 68e94. [10] M. Islam, R. Zailani, F. Ani, Pyrolytic oil from fluidised bed pyrolysis of oil palm shell and its characterisation, Renewable 17 (1999) 73e84. [11] A. Demirbas, Biomass resource facilities and biomass conversion processing for fuels and chemicals, Energy Convers. Manage. 24 (11) (2001) 1357e1378. [12] A. Oasmaa, S. Czernik, Fuel oil quality of biomass pyrolysis oils: state of the art for the end users, Energy Fuels 13 (1999) 914e921. [13] S.D. Stefanidis, K.G. Kalogiannis, E.F. Iliopoulou, C.M. Michailof, P.A. Pilavachi, A.A. Lappas, A study of lignocellulosic biomass pyrolysis via the pyrolysis of cellulose, hemicellulose and lignin, J Anal. Appl. Pyr. 105 (January) (2014) 143e150. [14] S. Xiu, A. Shahbazi, Bio-oil production and upgrading research: a review, Renew. Sustain. Energy Rev. 16 (2012) 4406e4414. [15] S.D. Stefanidis, K.G. Kalogiannis, E.F. Iliopoulou, A.A. Lappas, P.A. Pilavachi, Insitu upgrading of biomass pyrolysis vapors: catalyst screening on a fixed bed reactor, Bioresour. Technol. 102 (17) (2011) 8261e8267. [16] H.J. Park, J.I. Dong, J.K. Jeon, K.S. Yoo, J.H. Yim, J.M. Sohn, Y.K. Park, Conversion of the pyrolytic vapor of radiata pine over zeolites, J. Ind. Eng. Chem. 13 (2007) 182e189. [17] B. Valle, A.G. Gayubo, A.T. Aguayo, M. Olazar, J. Bilbao, Selective production of aromatics by crude bio-oil valorization with a nickel-modified HZSM-5 zeolite catalyst, Energy Fuels 24 (3) (2010) 2060e2070. [18] I.A. Aldobouni, A.B. Fadhil, I.K. Saied, Conversion of De-oiled castor seed cake into bio-oil and carbon adsorbents, Energy Sources Part A 37 (24) (2015) 2617e2624. [19] N.A.V. Santos, Z.M. Magriotis, A.A. Saczk, G.T.A. F assio, S.S. Vieira, Kinetic study of pyrolysis of castor beans (Ricinuscommunis L.) presscake: an alternative use for solid waste arising from the biodiesel production, Energy Fuels 29 (4) (2015) 2351e2357. [20] http://www.nrel.gov/docs/gen/fy13/42618.pdf. [21] http://www.nrel.gov/docs/gen/fy08/42619.pdf. [22] G. Merkouropoulos, A. Kapazoglou, V. Drosou, E. Jacobs, A. Krozlig, C. Papadopoulos, et al., Dwarf hybrids of the bioenergy crop Ricinus communis suitable for mechanized harvesting reveal differences in morphophysiological characteristics and seed metabolic profiles, Euphytica (2016 May), http://dx.doi.org/10.1007/s10681-016-1702-6. [23] C. Michailof, T. Sfetsas, S. Stefanidis, K. Kalogiannis, G. Theodoridis, A. Lappas, Quantitative and qualitative analysis of hemicellulose, cellulose and lignin bio-oils by comprehensive two-dimensional gas chromatography with timeof-flight mass spectrometry, J. Chromatogr. A 1369 (November) (2014) 147e160.
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11 [24] E. Alexopoulou, Y. Papatheohari, F. Zanetti, K. Tsiotas, I. Papamichael, M. Christou, et al., Comparative studies on several castor (Ricinus communis L.) hybrids: growth, yields, seed oil and biomass characterization, Ind. Crops. Prod. 75 (August) (2015) 8e13. [25] J.B. Sluiter, R.O. Ruiz, C.J. Scarlata, A.D. Sluiter, D.W. Templeton, Compositional analysis of lignocellulosic feedstocks. 1. Review and description of methods, J. Agric. Food Chem. 58 (16) (2010) 9043e9053. [26] K.H. Kim, jy Kim, T.S. Cho, J.W. Choi, Influence of pyrolysis temperature on physicochemical properties of biochar obtained from the fast pyrolysis of pitch pine (Pinus rigida), Bioresour. Technol. 118 (August) (2012) 158e162. [27] S. Sensoz, D. Angin, Pyrolysis of safflower (Charthamus tinctorius L.) seed press cake: part 1. The effects of pyrolysis parameters on the product yields, Bioresour. Technol. 99 (13) (2008) 5492e5497. lez, J. Gonz [28] J.M. Encinar, J.F. Gonza alez, Fixed-bed pyrolysis of Cynara cardunculus L. product yields and compositions, Fuel Process Technol. 68 (3) (2000) 209e222. [29] T. Sfetsas, C. Michailof, A. Lappas, Q. Li, B. Kneale, Qualitative and quantitative analysis of pyrolysis oil by gas chromatography with flame ionization detection and comprehensive two-dimensional gas chromatography with time-offlightmass spectrometry, J. Chromatogr. A 1218 (2011) 3317e3325. [30] E. Doumer, G.G.C. Arízaga, Da Silva da, C.I. Yamamoto, E.H. Novotny, J.M. Santos, et al., Slow pyrolysis of different Brazilian waste biomasses as sources of soil conditioners and energy, and for environmental protection, J Anal. Appl. Pyr. 113 (2015) 434e443. [31] B. Vishwanadham, R.H. Sripathi, D. Sadasivudu, A.A. Khan, Pyrolysis of castor oil methylesters to 10-undecenoic acid and heptaldehyde, Indian J Chem. Technol. 2 (1995) 119e128. [32] g Das, rk Trivedi, A.K. Vasishtha, Heptaldehyde and undecylenic acid from
11
Castor oil, J Am. Oil Chem. Soc 66 (1989) 938e941. [33] P. Biller, A.B. Ross, Potential yields and properties of oil from the hydrothermal liquefaction of microalgae with different biochemical content, Bioresour. Technol. 102 (1) (2011) 215e225. [34] R.V.S. Silva, A. Casilli, A.L. Sampaio, B.M.F. Avila, M.C.C. Veloso, D.A. Azevedo, G.A. Romeiro, The analytical characterization of castor seed cake pyrolysis biooils by using comprehensive GC coupled to time of flight mass spectrometry, J. Anal. Appl. Pyr. 106 (March) (2014) 152e159. € holm, Py[35] K.G. Kalogiannis, S.D. Stefanidis, C.M. Michailof, A.A. Lappas, E. Sjo rolysis of lignin with 2DGC quantification of lignin oil: effect of lignin type, process temperature and ZSM-5 in situ upgrading, J Anal. Appl. Pyr. 115 (September) (2015) 410e418. [36] E.F. Iliopoulou, S.D. Stefanidis, K.G. Kalogiannis, A. Delimitis, A.A. Lappas, K.S. Triantafyllidis, Catalytic upgrading of biomass pyrolysis vapours using transition metal-modified ZSM-5 zeolite, Appl. Catal. B Environ. 127 (October) (2012) 281e290. [37] J. Adam, M. Blazso, E. Meszaros, M. Stocker, M. Nilsen, A. Bouzga, et al., Pyrolysis of biomass in the presence of Al-MCM-41 type catalysts, Fuel 84 (12e13) (2005) 1494e1502. [38] J. Adam, E. Antonakou, A. Lappas, M. Stocker, M.H. Nilsen, A. Bouzga, In situ catalytic upgrading of biomass derived fast pyrolysis vapours in a fixed bed reactor using mesoporous materials, Microporous Mesoporous Mater. 96 (1e3) (2006) 93e101. [39] E. Antonakou, A. Lappas, M.H. Nilsen, A. Bouzga, M. Stocker, Evaluation of various types of Al-MCM-41 materials as catalysts in biomass pyrolysis for the production of bio-fuels and chemicals, Fuel 85 (14e15) (2006) 2202e2212. [40] M.A. Jackson, D.L. Compton, A.A. Boateng, Screening heterogeneous catalysts for the pyrolysis of lignin, J Anal. Appl. Pyr. 85 (2009) 226e230.
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
Contents lists available at ScienceDirect
Biomass and Bioenergy journal homepage: http://www.elsevier.com/locate/biombioe
Research paper
Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis Konstantinos G. Kalogiannis a, *, Stylianos D. Stefanidis a, b, Chrysoula M. Michailof a, Angelos A. Lappas a, ** a b
Chemical Process and Energy Resources Institute, Centre for Research and Technology Hellas, 6th km Harilaou-Thermi road, 57001, Thessaloniki, Greece Department of Mechanical Engineering, University of Western Macedonia, Bakola & Sialvera, 50100, Kozani, Greece
a r t i c l e i n f o
a b s t r a c t
Article history: Received 29 February 2016 Received in revised form 29 June 2016 Accepted 1 July 2016 Available online xxx
Castor oil is a vegetable oil obtained by pressing the seeds of the castor oil plant (Ricinus communis). Its production leads to high volumes of solid residues, the castor bean cakes. The main objective of this study was to investigate the potential of these castor bean cakes as a valuable source for production of high added value products such as bio-fuels and renewable chemicals. The upgrading of the castor bean cakes was attempted via thermochemical processes; specifically fast thermal and catalytic pyrolysis. Initially thermal pyrolysis of two different castor cakes and one type of castor stalks took place in a fixed bed fast pyrolysis reactor. The best feed was chosen for catalytic pyrolysis testing where industrially available microporous and one mesoporous catalyst were studied. Mass balances and products characterization via elemental analysis and two dimensional gas chromatography coupled to time-of-flight mass spectrometry (GCxGC-TOFMS) in the case of the liquid products allowed for the estimation of the catalytic effect in each case. © 2016 Published by Elsevier Ltd.
Keywords: Castor bean cake Biomass pyrolysis ZSM-5 Catalytic upgrading GCxGC-ToFMS
1. Introduction Castor (Ricinus Communis L.) is an oilseed crop containing a very high oil mass fraction ranging from 42 to 58% of the seeds weight. The castor oil is not used for edible purposes as it contains ricinoleic acid, a monounsaturated hydroxy 18-carbon fatty acid at 84e90% of its total fatty acid mass fraction [1]. Among fatty acids, ricinoleic acid is unusual in that it has a hydroxyl functional group on the 12th carbon. This functional group causes ricinoleic acid (and castor oil) to be more polar than most fats. The chemical reactivity of the alcohol group also allows chemical derivatization that is not possible with most other seed oils. Because of its ricinoleic acid mass fraction, castor oil is a valuable feedstock, commanding a higher price than other seed oils. Castor oil and its derivatives are used in the manufacturing of soaps, lubricants, hydraulic and brake fluids, paints, dyes, coatings, inks, cold resistant plastics, waxes and polishes, nylon, pharmaceuticals and perfumes [2]. In 2013, a total of 681,000 tonnes of castor oil was produced
* Corresponding author. ** Corresponding author. E-mail addresses: [email protected] (K.G. Kalogiannis), [email protected]. gr (A.A. Lappas).
globally with India production accounting for more than 81% of the total world production. The castor oil prices for 2013 were more than 1600 $ t1. However, the castor oil production is accompanied by high volumes of byeproducts such as the extracted castor cakes or the residues of the plant (e.g. leaves, stems etc.) that may amount up to quantities equal or higher than the oil itself thereby affecting the economics of the total castor production [3,4]. In addition, the castor cake contains significant amounts of allergens and ricin, a protein with toxicity for humans and animals, while the stems and residual plant parts contain alkaloids and in particular ricinine, which is also toxic for humans and animals. Evidently, these factors limit the uses of the by-products to certain applications such as their use as fertilizer, while the castor cakes might also be used for animal feed but only after detoxification treatments [5]. Consequently, alternative processes for the utilization and valorization of castor cake, stalks etc. are required. On the other hand, renewable energy has been the focus of research efforts in the past years due to the increasing world energy demand, finite oil/natural gas reserves and concerns over energy security and the protection of the environment. This has strongly motivated our society to search for alternative energy sources and specifically liquid transportation fuels [6e8]. Biomass is an abundant renewable carbon source that can help mitigate the
http://dx.doi.org/10.1016/j.biombioe.2016.07.001 0961-9534/© 2016 Published by Elsevier Ltd.
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
2
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
dependence on fossil fuels and the emission of greenhouse gases, via its conversion to gaseous, liquid and solid energy carriers through thermochemical processes (i.e. fast and/or slow pyrolysis, gasification etc.). Biomass fast pyrolysis is a very interesting technology for the production of liquid oil (bio-oil), which is considered to be a very promising biofuel/bioenergy carrier and a source of renewable high added value chemicals. Bio-oil is a complex mixture of oxygenated compounds originating from the thermal decomposition of the cellulose, hemicellulose and lignin, the main constituents of lignocellulosic biomass [9e13]. The acids, ketones, aldehydes and other oxygenates in the bio-oil are responsible for a series of undesirable properties, such as low calorific value, corrosiveness, instability under storage and transportation conditions, immiscibility with hydrocarbon fuels and high viscosity [14]. In order to upgrade the low quality bio-oil produced by thermal pyrolysis, heterogeneous catalysts are employed [15e17]. The pyrolysis vapors come in contact with a solid catalyst and are cracked, deoxygenated and selectively converted to more desirable compounds, such as aromatic hydrocarbons and simpler phenols. This results in a lighter bio-oil with improved properties and higher calorific mass fraction. Oxygen is removed in the form of gas CO2 and CO and by the formation of H2O. The application of fast pyrolysis presents an interesting alternative for the valorization of by-products from the castor oil production, however to the best of the authors’ knowledge it has been scarcely reported in the literature. Among the few dedicated publications is one from Aldobouni et al. [18] who pyrolyzed castor bean cakes for production of bio-oil and carbon adsorbents from the residual pyrolysis char, while Santos et al. studied the kinetics of castor bean presscake pyrolysis [19]. This work presents the thermal and catalytic fast pyrolysis of castor cakes and stalks from castor plants cultivated in Southern Greece during 2013. Four commercially available catalysts have been studied for their effect on the pyrolysis products. Much emphasis has been placed on the analysis of the bio-oils by GCxGC-ToFMS in order to clarify the composition of the bio-oils and elucidate the effect of the catalysts.
2. Materials and methods 2.1. Biomass samples and characterization Three biomass samples were used in this study; two castor bean cakes (castor cake #1 and castor cake #2) and a sample of castor stalks. Carbon, hydrogen and nitrogen mass fractions in the biomass samples were determined by a CHN LECO-800 elemental analyzer from Leco Corporation (USA). Oxygen mass fraction was determined by difference. The moisture mass fraction was measured by drying a pre-weighed sample at 105 C for 4 h. The total ash mass fraction was measured by combustion of 2 g of sample in a muffle furnace at 600 C for 16 h. Inductive coupled plasma-atomic emission spectroscopy (ICP-AES) was used for the determination of the inorganic mass fraction of the biomass samples, utilizing a Perkin Elmer Plasma 400 spectrometer. The hemicellulose, cellulose and lignin mass fraction were determined according to the well-known NREL methods (NREL/TP-510-42618 [20] and NREL/TP-510-42619 [21]). Finally the protein mass fraction was measured according to the N-Kjeldahl method (AOAC 955.04). For further information regarding the initial castor plants the reader is kindly referred to the work by Merkouropoulos et al. [22] where castor cake #1, castor cake#2 originated from the hybrids H11 and H14 respectively while the castor stalks used in this work were those from the H14 variant.
2.2. Catalysts For thermal pyrolysis silica sand was used that acted as inert material. The silica sand had particle size ranging between 90 and 500 mm, near zero specific surface area, due to the zero internal porosity of silica sand particles, and no acidity nor basicity. It was therefore a fully inert material with no catalytic effect that served as the base case material for testing different feedstocks and pyrolysis temperatures. N2 adsorption-desorption experiments at 196 C were performed on an Automatic Volumetric Sorption Analyzer (Autosorb-1, Quantachrome) for the determination of surface area (BET method), total pore volume at P/Po ¼ 0.99, micropore volume (t-plot method), and pore size distribution (BJH method) of the samples that were previously outgassed at 150 C for 16 h under vacuum at 5 109 Torr. For catalytic pyrolysis commercially available catalysts were used which are presented in Table 1. It should be noted that all the catalysts were fluidizable and in a microparticle formulation. Their average size ranged between 60 and 90 mm, which is typical of the commercially available catalysts. The ZSM-5 catalyst labeled ZSM-5, along with its Co-doped variant, labeled Co-ZSM-5, had 30% by mass of the ZSM-5 zeolite on a silicaalumina matrix with a Si to Al mass ratio of 20. The FCC catalyst was itself a USY zeolite on a silica-alumina matrix. All the above catalysts were microporous, in contrast to the Al-MCM-41 catalyst that was a mesoporous acidic material. 2.3. Description of bench scale biomass fast pyrolysis unit and experimental procedures and conditions 2.3.1. Description of bench scale biomass fast pyrolysis unit All pyrolysis experiments were performed at 500 C and 600 C, using a bench-scale fixed bed reactor, made of stainless steel 316 and heated by a 3-zone furnace. The temperature of each zone was independently controlled using temperature controllers. The catalyst bed temperature was used as the experiment temperature and this was monitored with a thermowell. A specially designed piston system was used to introduce the biomass feedstock into the reactor. A constant stream of N2 was fed from the top of the reactor for the continuous withdrawal of the products and maintenance of the inert atmosphere during pyrolysis. The products exited from the bottom of the reactor in gaseous form and were condensed in a glass receiver submerged in a cooling bath kept at 17 C. Noncondensable gases were collected in a gas collection system. A filter placed between the glass receiver and the gas collection system recovered any condensable gases that were not condensed in the receiver. A schematic diagram of the experimental set-up is given in Fig. 1. Further details may be found elsewhere [15]. 2.3.2. Pyrolysis process and products collection The reactor was filled with 0.7 g catalyst or silica sand for the catalytic and non-catalytic tests respectively and the piston was filled with 1.5 g of biomass. As soon as the desired temperature was reached, the biomass was introduced into the reactor and the experiment began using 100 cm3 min1 nitrogen flow. At the end of the experiment (15 min), the reactor was cooled and purged for 10 min with N2 (50 cm3 min1). For all tests the reactor temperature was kept constant at the selected temperature. The catalyst bed dimensions depend on the catalyst’s apparent bulk density. Residence times depend on catalyst bed height, catalyst bed void fraction and cracked gases volume. A typical residence time of the vapor phase in the bed was 31 ms (calculated for the FCC catalyst). The above described catalytic pyrolysis experiments are of the “exbed” type, i.e. there is no mixing of the solid biomass with the solid catalyst or silica sand.
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
3
Table 1 Catalyst properties employed in this study. Catalyst
Surface area (m2 g1)
Mean pore diameter (1010 m)
Microporosity (cm3 g1)
Mesoporosity (cm3 g1)
Silica sand ZSM-5 Co-ZSM-5 FCC Al-MCM-41
0 138 131 176 337
e 40 36 6 e
e 0.037 0.036 0.035 e
e 0.071 0.082 0.242 e
Fig. 1. Schematic view of CPERI bench scale fixed bed biomass pyrolysis unit.
The liquid products were collected and quantitatively measured in the pre-weighted glass receiver. The pyrolytic vapors, upon their condensation in the glass receiver, formed multiple phases; an aqueous phase, a liquid organic phase and viscous organic deposits on the receiver walls. A method for collecting a representative biooil sample for analysis is described elsewhere [15]. The gas products were collected and measured by the water displacement method and the amount of the solid residue formed was measured by direct weighing. The solid products consisted of charcoal (biomass residue) and coke-on-catalyst formed by thermal and catalytic cracking, as well as a very small amount of unreacted biomass. The unreacted biomass was subtracted from all mass balance calculations. The amount of condensable vapors recovered in the filter was also measured by direct weighing and was added to the liquid products yield. Three experiments under the same conditions were run for each catalytic material in order to ensure repeatability and the average values from the three experimental runs were used.
2.3.3. Methods for pyrolysis gases and bio-oil analysis The water mass fraction of the bio-oil was determined by the Karl-Fischer method (ASTM E203-08) and the carbon, hydrogen and nitrogen mass fraction was determined with an elemental CHN
LECO-800 analyzer. The gaseous products were qualitatively and quantitatively analysed on a HP 5890 Series II gas chromatograph, equipped with four columns (Precolumn: OV-101; Columns: Porapak N, Molecular Sieve 5A and Rt-Qplot (30 m 0.53 mm ID) and two detectors (TCD and FID). Gas products consisted of CO, CO2, CH4, H2 and hydrocarbons with up to 6 carbon atoms.
2.3.4. GCxGC-ToFMS bio-oil characterization Qualitative and quantitative analysis of the bio-oils was performed by means of GCxGC-ToFMS. The analytical system employed consisted of an Agilent 7890A gas chromatograph with an Agilent 7683B series (Agilent Technologies, Palo Alto, CA, USA) injector connected to a Pegasus 4D time-of-flight mass spectrometer from Leco Instruments (St. Joseph, MI, USA). The samples for the GCxGC-ToFMS analysis were prepared from a separate pyrolysis experiment, where the sample collection from the receiver was performed by addition of a weighed amount of MeOH. The samples were further appropriately diluted in MeOH prior to injection, without any other pretreatment. The analysis of the samples was both qualitative and quantitative and further details regarding the chromatographic method employed have been previously reported in detail [23].
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
4
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
3. Results and discussion 3.1. Characterization of biomass samples Characterization of the three feedstocks used in this study is presented in Table 2. Elemental analysis showed that the castor bean cakes have lower oxygen mass fraction compared to more typical biomass such as the castor stalks, but they have significantly higher N-mass fraction, due to their alkaloid and protein concentration [24]. Additionally, ICP analysis (Table 2) showed very high mass fraction of some alkali metals, specifically Potassium (K), Magnesium (Mg), Calcium (Ca) and in the case of the castor bean cakes Phosphorus (P) as well. Finally, the extractives, lignin, cellulose, hemicellulose and proteins mass fraction is presented for all feeds. The castor bean cakes differ significantly to the castor stalks. They have very low cellulose and hemicellulose mass fraction but an increased extractives mass fraction. The extractives represent the non-structural components of biomass and include waxes, inorganic material, nitrogenous material, sugar acids, and nonstructural components [25] and in this particular case, residual castor oil as well. Additionally, castor bean cakes have increased proteins mass fraction. In contrast the castor plant stalks bear higher resemblance to a typical lignocellulosic biomass with low protein and higher cellulose and hemicellulose mass fractions.
3.2. Fast pyrolysis experimental results 3.2.1. Thermal pyrolysis In Table 3 the mass balances of the main products, that is gases, coke, water and bio-oil organic phase are presented. In the case of both castor cake samples, both the organic phase and coke production were higher compared to the castor stalks. Gases and water production on the other hand were lower in the case of the castor cakes. Increasing temperature resulted in enhanced cracking of the bio-oil vapors. This in turn led to an increase in the gases and water production while coke and the bio-oil organic phase yields were reduced, as has been also previously reported [26,27]. Especially in the case of the castor bean cake #2, increasing the reaction temperature led to an increase of the light hydrocarbons
Table 2 Castor bean cakes and stalks elemental, ICP and biomass components analysis on dry feedstock. Elemental analysis (% by mass)
Castor cake#1
Castor cake#2
Castor stalks
C H O N Ash Alkali (% by mass) Al Ca Cu Fe Na Mg Mn K P Zn Component, (% by mass) Extractives Hemicellulose Cellulose Acid insoluble lignin Acid soluble lignin Proteins
50.8 6.8 33.6 3.2 5.6
51.7 7.0 31.5 4.2 5.6
43.2 6.1 44.7 1.6 4.4
0.002 0.366 0.002 0.008 0.059 0.511 0.002 1.230 1.070 0.009
0.003 0.290 0.002 0.007 0.077 0.485 0.002 1.352 1.053 0.008
0.0112 0.896 0.001 0.006 0.039 0.131 0.001 0.624 0.221 0.002
29.5 4.4 3.8 29.3 5.1 23.0
29.4 5.2 3.5 33.0 4.5 23.1
18.6 13.6 33.4 17.6 2.5 4.9
yields, C1eC6 as can be seen in Table 4. The secondary decomposition of char at higher temperatures has also been found to produce some gaseous products, increasing the overall gas yield [28]. Interestingly enough, the castor cakes produced better quality bio-oils with significantly lower oxygen mass fraction compared to the castor stalks (Table 3), assumingly due to the presence of residual oil in the cake. This was confirmed by the significantly higher CO2 yield, compared to CO yield from castor stalks, which could be attributed to decarboxylation reactions of the fatty acids of residual castor oils. However, increasing the reaction temperature had an adverse effect for the castor cakes. The bio-oil yield was decreased as noted above, but also the bio-oil quality worsened since its oxygen mass fraction increased, in particular in the case of the castor cake #2. The increase of the oxygen mass fraction is attributed to the overcracking of the bio-oil vapors. Essentially, more light hydrocarbons were formed, which were received as gases that reduced the carbon available in the bio-oil. This is not typical of lignocellulosic biomass as can be seen in the case of the high temperature pyrolysis of the castor stalks. In the case of the castor stalks, increasing the reaction temperature led to the expected decrease in the bio-oil yield, accompanied by a slight decrease of the bio-oil’s oxygen mass fraction due to enhanced deoxygenation. These findings are graphically represented in Fig. 2 where bio-oil yield is presented versus the oxygen mass fraction of the bio-oil. In addition, comparing the two castor bean cakes, it appears that castor bean cake #2 resulted in slightly higher bio-oil yield with a lower oxygen mass fraction. Taking these into account, it was decided to test catalytic pyrolysis at 500 C and with the castor bean cake #2. The composition of the three thermal bio-oils was elucidated by GCxGC-ToFMS analysis. The qualitative identification of the compounds was based mainly on the match of the spectra with those of the official library NIST05, considering as minimum identification criteria S/N at 50 and similarity value at 700. Borderline group-type classification was employed for the determination of the specific elution areas of the different classes of compounds on the chromatogram. In total 7 groups were clearly defined in the chromatographic space: 1. Acids and esters, 2. Aldehydes and ketones (including furanoics and cyclic carbonyl compounds), 3. Hydrocarbons (non-aromatic saturated and unsaturated hydrocarbons), 4. Aromatic hydrocarbons, 5. Phenolic compounds (including guaiacols, syringols, anisols and catechols), 6. Long-chain organic acids and 7. Sugars [29]. Fig. 3 presents the chromatograms of castor cake #2 and castor stalks bio-oil. The chromatogram of castor cake #1 bio-oil was the same as that of castor cake #2 bio-oil and therefore it is not presented. By comparing the peak density in each area of the chromatogram, it is possible to get a primary rough estimation of the differences the samples might present. More than 400 peaks were detected in the castor cake bio-oils and 281 in the castor stalk bio-oil. The total number of unidentified peaks in each chromatogram was very small. It is worth pointing out that the major part of the detected bio-oil’s chromatogram area (>1%) is attributed to less than 20 peaks (Table 5). However, for a better representation of the compounds distribution over the chromatographic area, the individual peaks were assigned to groups, and the summation of their relative area % is presented in Fig. 4. The relative area % peaks distribution of the castor cake bio-oils indicate that it is rich in organic acids (mainly long chain) [30] and phenolic derivatives. The main peak in the chromatogram (Fig. 3a) corresponds to undecylenic acid and represents almost 20% of total chromatographic area. Undecylenic acid, along with heptanal, are formed as a result of the thermal decomposition of ricinoleic acid at temperatures higher than 300 C [31,32]. Furthermore, the decomposition of the residual oil of the castor cakes results in the
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
5
Table 3 Thermal pyrolysis mass balances and dry bio-oil elemental composition. Feedstock þ pyrolysis temperature
Castor Castor Castor Castor Castor a
Cake#1 þ 500 C Cake#2 þ 500 C stalks þ500 C Cake#2 þ 600 C stalks þ600 C
Yields, % by mass on dry feedstock
Bio-oil organic phase, % by mass
Bio-oil
Water
Organics
Gas
Coke
C
H
N
Oa
52.5 52.4 56.3 46.9 48.9
18.8 18.0 29.5 20.5 26.8
33.7 34.4 26.8 26.5 22.1
12.4 13.0 19.1 22.6 27.3
35.1 34.6 24.6 30.5 23.8
63.4 64.0 58.0 59.9 58.8
10.1 10.2 7.7 9.6 7.7
9.9 9.5 0.6 10.1 0.4
16.6 16.3 33.7 20.4 33.1
Oxygen mass fraction is calculated by difference.
Table 4 Thermal pyrolysis gases on dry feedstock. Feedstock þ pyrolysis temperature
Castor Castor Castor Castor Castor
Cake#1 þ 500 C Cake#2 þ 500 C stalks þ500 C Cake#2 þ 600 C stalks þ600 C
Individual gas yields, % by mass on dry feedstock CO2
CO
H2
CH4
C2H6
C2H4
C3H8
C3H6
C4eC6
8.5 9.2 12.7 10.2 14.7
2.1 2.1 4.9 4.4 8.8
0.0 0.0 0.0 0.1 0.2
0.3 0.3 0.6 1.5 1.8
0.3 0.3 0.2 0.8 0.4
0.2 0.2 0.1 2.0 0.4
0.2 0.1 0.1 0.3 0.1
0.2 0.3 0.1 1.6 0.3
0.6 0.5 0.4 1.7 0.6
Fig. 2. Thermal pyrolysis bio-oil yield vs bio-oil oxygen mass fraction.
formation of saturated and unsaturated hydrocarbons [33] with Cchain length between C9 to C20, as indicated by the peaks in the respective area. Additionally, the castor cake bio-oils contain a significant number of N-compounds, due to the thermal decomposition of the proteins in the castor cakes. In particular, proteins produce large amounts of nitrogen heterocycles, pyrroles, and indoles [33]. However, these compounds are distributed throughout the chromatogram and co-eluted in the areas of the oxygenated compounds with similar structure (i.e. pyrrole and its derivatives are eluted in the aldehydes and ketones area along with furans) therefore they could not be separated as a specific group. The Ncompounds identified are mainly pyrrole, pyridine and amide derivatives, with amides and pyrroles being the prevailing groups. Similar results pertaining the groups of compounds in the castor cake bio-oils were presented in the work of Silva et al. [34], however the distribution of the groups is different due to the different
Fig. 3. GCxGC-ToFMS chromatograms of (a) castor cake #2 bio-oil (b) castor stalk bio-oil (the chromatogram of castor cake #1 bio-oil is the same as that of castor cake #2 bio-oil and therefore is not presented here).
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
6
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
Table 5 Distribution of peaks based on relative peak area and number of total, unidentified and quantified peaks (numbers in parentheses correspond to total peak area). Sample
Total peaks
Castor 405 cake#1 Castor 461 cake#2 Castor 281 stalks
Unidentified peaks
No. of peaks with rel. Area >1%
No. of peaks with rel. Area >0.5%
No. of peaks with rel. Area >0.3%
No. of peaks with rel. Area >0.1%
%Area quantified
No. of quantified peaks
78 (3.4%)
16 (61.9%)
26 (68.7%)
48 (77.6%)
114 (89.0%)
31.2
32
60 (2.9%)
16 (61.9%)
29 (69.9%)
48 (77.6%)
110 (88.1%)
29.4
34
27 (0.6%)
18 (70.2%)
33 (80.7%)
45 (85.01%)
96 (93.6%)
83.7
104
Fig. 4. Distribution of groups detected in the thermal bio-oils based on their relative area % (AR: aromatic hydrocarbons, ALI: aliphatic hydrocarbons, PH: phenolic compounds, FUR: furanic compounds, AC: organic acids, EST: esters, AL: alcohols, ETH: ethers, ALD: aldehydes, KET: ketones, PAH: polyaromatic hydrocarbons, SUG: sugars, NIT: N-compounds, UN:unidentified).
production conditions (slow pyrolysis at 380 C). In the case of castor stalks bio-oil, its chromatographic profile (Fig. 3b) is similar to that resulting from conventional woody biomasses. It contains primarily phenolic compounds, mainly due to the decomposition of lignin, along with carbonyl compounds (i.e. furfural and cyclopentanones) due to the cellulose and hemicellulose decomposition. The prevailing peak in the chromatogram is that of acetic acid (in the acids area at the beginning of the chromatogram), which represents almost 40% of the total chromatographic space. Neither long-chain organic acids nor hydrocarbons are detected. However, due to the small protein mass fraction of the
stalks (4.9% by mass) some N-compounds are detected, mainly cyclic 5 and 6-membered compounds. A GCxGC-ToFMS quantification method for bio-oils originating from lignocellulosic biomass has been previously developed and applied for the analysis of bio-oils of different origin [23,29,35]. This method has been applied in this case as well, however since it does not include N-compounds neither long-chain organic acids, only a very small percentage of the castor cake bio-oil was estimated quantitatively (5.3 and 4.1% mass fraction of the organic phase of the bio-oil). In both cases, the main compounds identified were acetic acid (3.2 and 2.4% by mass respectively), catechol and methyl
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
catechols. It should be noted that acetic acid which is a typical component of the thermal bio-oils, was detected at very low concentration in this case, due to the very low mass fraction of cellulose and hemicellulose in the original biomass. On the contrary, the castor stalk bio-oil composition is quantified to a greater extent. In particular, 10.2% by mass of the organic phase of the castor stalks bio-oil is attributed to organic acids (mainly acetic acid), 8% by mass is attributed to phenolic compounds (syringol and 1,2-benzendiol are the main components), while 9.4% by mass corresponds to total carbonyl compounds (30 ,50 -Dimethoxyacetophenone, furfural, furanone and cyclopentanone derivatives are the main components).
3.2.2. Catalytic pyrolysis The ZSM-5 and FCC catalysts are industrially available catalysts while the Co-ZSM-5 is the industrially available catalyst impregnated with 5% by mass Co by the wet impregnation method which can be found elsewhere [36]. The experimental results of catalytic pyrolysis of castor cake #2 are presented in Tables 6 and 7. In Table 6 the mass balances of the main products, that is gases, coke, water and bio-oil organic phase are presented. The elemental analysis of the derived organic phases of the bio-oils is also presented in Table 6. The individual gases yields when the various catalysts were applied are presented in Table 7. In all cases the in situ catalytic upgrading leads to increase in the water yield, gases and coke, while the bio-oil yield is decreased. The use of catalysis increased gases production, especially the light hydrocarbons, in part due to further cracking of some of the residual castor oil towards lower MW products such as C4eC6. The Co doped ZSM-5 and the FCC catalysts had a milder effect while the ZSM-5 and the Al-MCM-41 mesoporous catalyst appear to be the most active materials, producing the least bio-oil. A significant difference was noted between these two materials. The ZSM-5 catalyst did not increase coke production, while the Al-MCM-41 increased coke production significantly. Table 6 presents the C measured on the silica sand particles and the various catalysts. The C on the catalyst is catalytically produced coke due to the conversion reactions taking place when the bio-oil vapors come into contact with the catalyst. The ZSM-5 catalyst, known for its shape selectivity and two dimensional pore structure, did not significantly increase coke production (only ~ 2% by mass C on catalyst was measured). The Al-MCM-41 on the other hand, allowed condensation reactions to continue on its large mesopores leading to polyaromatics and increased coke production. The Co-ZSM-5 and the FCC catalysts produced more coke but still quite lower compared to the mesoporous Al-MCM-41. In Table 6 the elemental analysis of the produced bio-oils is presented on a dry basis. The ZSM-5 catalyst produced the most deoxygenated bio-oil with an oxygen mass fraction of less than 7%. In addition, the N-mass fraction of the bio-oil also decreased which is a further positive effect. The Al-MCM-41 catalyst on the other hand barely deoxygenated the bio-oil, although it sacrificed a significant part of the
7
Table 7 Catalytic pyrolysis gases on dry feedstock. Catalyst
Silica sand ZSM-5 Al-MCM-41 Co/ZSM-5 FCC
Individual gas yields, % by mass on dry feedstock CO2
CO
H2
CH4
C2H6
C2H4
C3H8
C3H6
C4eC6
9.2 8.6 9.1 8.9 8.8
2.1 2.6 2.4 2.6 2.3
0 0 0 0.1 0
0.3 0.4 0.5 0.3 0.4
0.3 0.3 0.5 0.3 0.4
0.2 0.4 0.3 0.4 0.3
0.1 0.2 0.3 0.2 0.3
0.3 0.7 0.4 0.7 0.4
0.5 1.5 1.2 1.1 1
bio-oil yield. This adverse effect was attributed to the mesoporosity of the material. The large mesopores allowed for condensation reactions to continue uncontrolled, leading to the transformation of aromatic compounds to polyaromatic and then to coke. This resulted in increased carbon losses towards the solid coke product which in turn meant that less carbon was available for the liquid product. This effect has also been reported by other researchers. They found that pore enlargements led to higher molecular weight products [37]. Adam et al. studied four different Al-MCM-41 materials and found that PAHs yield increased significantly while pore size enlargement had a deteriorating effect on the bio-oil quality [38]. Antonakou et al. made similar observations studying Al-MCM41 materials with different Si/Al ratios, where it was found that biooil yield decreased while coke production increased significantly [39]. Jackson et al. also compared a ZSM-5 zeolite to a mesoporous Al-MCM-41 for the upgrading of lignin pyrolysis vapors and observed that the AlMCM-41 catalyst behaved similarly to the ZSM5, although it was not as effective at deoxygenating the liquid phase and gave more naphthalenics than simple aromatics [40]. In our work, the ZSM-5 catalyst, which features a very well defined microporous structure, minimized condensation reactions, managing to keep the carbon in the liquid product, hence the increased process efficiency. Fig. 5 presents the above findings schematically, where bio-oil yield is presented vs the bio-oil oxygen mass fraction. The catalytic bio-oils were further analysed by GCxGC-ToFMS.
Fig. 5. Catalytic pyrolysis bio-oil yield vs bio-oil oxygen mass fraction.
Table 6 Catalytic pyrolysis mass balances and dry bio-oil elemental composition. Catalyst
Silica sand ZSM-5 Al-MCM-41 Co/ZSM-5 FCC
Yields, % by mass on dry feedstock
C on cat.
Bio-oil
Water
Organics
Gas
Coke
52.4 52.8 48.8 52.2 52.4
18.0 26.1 23.3 21.1 22.0
34.4 26.7 25.5 31.1 30.4
13.0 14.7 14.7 14.6 13.9
34.6 32.5 36.5 33.2 33.7
0.16 1.98 9.48 3.54 3.59
Bio-oil organic phase, % by mass on dry oil C (ORG)
H (ORG)
N (ORG)
O (ORG)
64.0 75.3 65.2 66.7 69.8
10.2 9.8 10.3 10.3 10.1
9.5 8.1 8.8 9.5 11.3
16.3 6.8 15.7 13.5 8.8
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
8
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
The respective chromatograms are presented in Fig. 6 while in Table 8 the total number of detected peaks is presented. The number of peaks in the catalytic bio-oils is almost twice that detected in the thermal bio-oils, indicating the extensive cracking of the biomasses to smaller compounds. The graphic representation of the peaks distribution in the assigned groups, based on their relative area % is presented in Fig. 7. The catalysts selected had a marked effect on the composition of the bio-oils compared to the thermal castor cake bio-oil, as there is an increase in the hydrocarbons (both non-aromatic and aromatic) mass fraction and a decrease in the phenolics and acids mass fraction. In particular, the catalysts increased the aromatics mass fraction in the order ZSM-5 > Co-ZSM-5 > FCC > Al-MCM-41. The respective quantitative analysis revealed that the aromatics concentration was 1.85 > 1.06>0.91 > 0.87% by mass of the organic phase of the bio-oils (the respective concentration for the thermal castor cake #2 bio-oil was 0.05% by mass) and was attributed
mainly to toluene, benzene and alkyl-benzenes. The bio-oil from the thermal pyrolysis of castor cake contains few non-aromatic hydrocarbons, and in particular olefins, possibly due to the thermal decomposition of the residual oil (Fig. 4). The addition of catalysts not only increased the non-aromatic hydrocarbons mass fraction but also had an effect on the type of hydrocarbons produced. The non-aromatic hydrocarbons mass fraction in the catalytic bio-oils decreased in the order Al-MCM-41 > FCC > ZSM5>Co-ZSM-5 which corresponds to actual concentration of 3.21 > 2.51>1.94 > 1.19% by mass of the organic phase of the bio-oils respectively and in each case was higher than the 0.09% by mass of the thermal bio-oil. In order to clarify the effect of the catalysts, the hydrocarbons peak areas were normalized based on their total area in each sample and were further divided to subgroups of n- and isoparaffins, n- and iso-olefins, as well as saturated and unsaturated naphthenes (Fig. 7). Based on the results, ZSM-5 and Co/ZSM-5 promote the formation of n- and iso-olefins while their tendency
Fig. 6. GCxGC-ToFMS chromatograms of catalytic bio-oils (A) ZSM-5, (B) Co-ZSM-5, (C) FCC, (D) Al-MCM-41.
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
9
Table 8 Distribution of peaks based on relative peak area and number of total, unidentified and quantified peaks (numbers in parenthesis correspond to total peak area). Sample
Total peaks
Unidentified peaks
No. of peaks with rel. Area >1%
No. of peaks with rel. Area No. of peaks with rel. Area No. of peaks with rel. Area %Area >0.5% >0.3% >0.1% quantified
Quantified
ZSM-5 FCC Co-ZSM5 Al_MCM_41
758 683 530 945
64 59 52 69
19 17 19 13
33 35 31 37
271 240 177 331
(3.2%) (1.6%) (1.5%) (1.1%)
(45.9%) (42.2%) (58.5%) (30.7%)
(55.6%) (55.1%) (66.8%) (46.6%)
51 60 45 68
(62.6%) (64.6%) (72.1%) (58.1%)
148 162 124 170
(79.6%) (81.3%) (84.9%) (75.8%)
59.6 53.2 52.9 54.2
Fig. 7. Distribution of groups detected in the catalytic bio-oils based on their relative chromatographic area %.
to form aromatics is reflected by the increase of the naphthenes. The doping of ZSM-5 with Co decreased the overall hydrocarbons produced compared to ZSM-5, but contrary to ZSM-5 it promoted the formation of paraffins. Similar behaviour is demonstrated by the FCC catalyst. Among the catalysts, the highest non-aromatic hydrocarbons mass fraction is produced by the Al-MCM-41 and is distributed mainly between n- and iso-olefins. This was expected
since the Al-MCM-41 material is an amorphous mesoporous material and is therefore suitable for cracking large molecules such as the residual organic acids found in the castor bean cake, towards lower molecular weight products. The shape selectivity of the ZSM5 material on the other hand increased the production of aromatic hydrocarbons. Regarding the phenolics concentration it has been decreased, compared to the respective concentration in the thermal
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
10
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11
bio-oil, in the order ZSM-5> Co/ZSM-5> FCC > Al-MCM-41 which corresponds to quantitative concentrations of 3.00 > 2.37>2.12 > 1.45% by mass of the organic phase of the biooils respectively as compared to the 1.37% by mass of the organic phase of the thermal bio-oil. The relative area of the phenolics of the thermal castor cake #2 bio-oil appears higher in Fig. 7, due to the fact that the chromatogram contains fewer peaks than the respective chromatograms of the catalytic bio-oils and consequently the relative area attributed to phenolics is higher. The actual quantitative analysis of the phenolics clarified the difference and highlighted the importance of differentiating between semiquantitative and quantitative results. As far as the acids are concerned, the thermal castor cake #2 bio-oil had a high peak attributed to undecylenic acid (18.8% of the chromatographic area). This peak was significantly lower in the catalytic bio-oils in the order Co-ZSM-5 >ZSM-5 ¼ FCC > Al-MCM-41, however the actual mass fraction of this acid could not be quantified. Nonetheless, the acetic acid mass fraction was determined quantitatively and was found to increase from 2.4% by mass of the organic phase in the thermal biooil to 6.2, 5.9 and 4.8% by mass in Co-ZSM-5, ZSM-5 and FCC bio-oils respectively, while it decreased to 1.8% by mass in the organic phase of the Al-MCM-41 bio-oil. Had there been a separation of the aqueous and organic phase of these bio-oils, most of the acetic acid would have partitioned to the aqueous phase, leaving the organic phase with decreased acidity compared to a thermal bio-oil, but in this case phase separation was not possible due to sample quantity limitations and therefore the total bio-oil was analysed. Finally the N-compounds occupy a significant percent of the chromatographic area and appear recalcitrant to the catalysts, as also indicated by the N-mass fraction of the catalytic bio-oils (Table 6). It appears that due to the catalysts the amides and pyridines are decreased, while the nitriles are increased, an effect most pronounced in the case of Al-MCM-41. The pyrrole derivatives appear unaffected by the catalysts tested. 4. Conclusions This work focused on investigating the thermal and catalytic pyrolysis of castor bean cakes and stalks at different temperatures in a fixed bed unit. Castor bean cakes were found to pyrolyze much more efficiently compared to castor stalks. This was attributed to the residual castor oil in the castor cakes that increased the organic oil yield while allowing for the transformation of the residual castor oil into valuable compounds such as aromatic hydrocarbons. The pyrolysis temperature of 500 C was found to be the most suitable one, since at the higher temperature of 600 C overcracking led to less bio-oil yield with higher oxygen mass fraction reducing the overall process efficiency. This was attributed to overcracking of the bio-oil vapors that resulted in a shift of the available C from the biooil towards gas products, especially light hydrocarbons. Moreover, GCxGC analysis revealed that the thermal oils consisted of organic acids, in particular undecylenic acid, due to the degradation of residual oils in the feed. Due to the high mass fraction of proteins in the castor cakes, a significant number of N- compounds was also detected. In situ catalytic upgrading allowed for the efficient deoxygenation of the castor bean cake bio-oil in a much more efficient manner, yielding a bio-oil with oxygen mass fraction less than 7% in the case of the ZSM-5 catalyst. The ZSM-5 catalyst was also found to decrease the N- mass fraction of the bio-oil. According to the chromatographic analysis ZSM-5 catalyst resulted in the increase of aromatic compounds such as benzene, toluene and xylene. The mesoporous Al-MCM-41 and the FCC catalyst on the other hand produced more aliphatic hydrocarbons but had significant losses of C towards coke production, especially so in the case of the mesoporous material. Overall, the castor cakes were found to
be a very interesting feedstock for the production of pyrolysis biooil, especially so in the case of the in situ catalytic upgrading that produced a higher quality product that could be potentially upgraded towards fuel. Acknowledgements The authors wish to acknowledge funding of this research from the project JONAН-FUEL, “CASTOR bean (JONAH seed) cultivation in central Macedonia, Greece and industrial exploitation of its derivatives towards BIOFUELs’ production”, agreement no. ISR_3176, which is co-funded by Greece and the European Regional Development Fund, under OPCE II and within the program ‘Bilateral R&D cooperation between Greece and Israel 2013e2015’. References ndez-Martínez, Velasco, in: J.M. Ferna ndez-Martínez, L. Velasco Castor, [1] Ferna S.K. Gupta (Eds.), Technological Innovations in Major World Oil Crops, Breeding, vol. 1, Springer, New York, 2012, pp. 237e265. [2] H. Mutlu, M.A.R. Meier, Castor oil as a renewable resource for the chemical industry, Eur J Lipid Sci. Technol. 112 (1) (2010) 10e30. [3] M. Pavaskar, A. Kshirsagar, Global Castor oil and indian monopoly, Financ. Vis. 1 (5) (2013) 15e19. n, Design and analysis of a second and [4] J. Moncada, C.A. Cardona, L.E. Rinco third generation biorefinery: the case of castor bean and microalgae, Bioresour. Technol. 198 (2015) 836e843. [5] L.S. Severino, D.L. Auld, M. Baldanzi, M.J.D. C^ andido, G. Chen, W. Crosby, et al., A review on the challenges for increased production of castor, Agron. J. 104 (4) (2012) 853e880. [6] H.B. Goyal, D. Seal, R.C. Saxena, Bio-fuels from thermochemical conversion of renewable resources: a review, Renew. Sustain. Energy Rev. 12 (2) (2008) 504e517. [7] Y.C. Lin, G.W. Huber, The critical role of heterogeneous catalysis in lignocellulosic biomass conversion, Energy Environ. Sci. 2 (2009) 68e80. [8] G.W. Huber, S. Iborra, A. Corma, Synthesis of transportation fuels from biomass: chemistry, catalysts, and engineering, Chem. Rev. 106 (9) (2006) 4044e4098. [9] A.V. Bridgwater, Review of fast pyrolysis of biomass and product upgrading, Biomass Bioenergy 38 (March) (2012) 68e94. [10] M. Islam, R. Zailani, F. Ani, Pyrolytic oil from fluidised bed pyrolysis of oil palm shell and its characterisation, Renewable 17 (1999) 73e84. [11] A. Demirbas, Biomass resource facilities and biomass conversion processing for fuels and chemicals, Energy Convers. Manage. 24 (11) (2001) 1357e1378. [12] A. Oasmaa, S. Czernik, Fuel oil quality of biomass pyrolysis oils: state of the art for the end users, Energy Fuels 13 (1999) 914e921. [13] S.D. Stefanidis, K.G. Kalogiannis, E.F. Iliopoulou, C.M. Michailof, P.A. Pilavachi, A.A. Lappas, A study of lignocellulosic biomass pyrolysis via the pyrolysis of cellulose, hemicellulose and lignin, J Anal. Appl. Pyr. 105 (January) (2014) 143e150. [14] S. Xiu, A. Shahbazi, Bio-oil production and upgrading research: a review, Renew. Sustain. Energy Rev. 16 (2012) 4406e4414. [15] S.D. Stefanidis, K.G. Kalogiannis, E.F. Iliopoulou, A.A. Lappas, P.A. Pilavachi, Insitu upgrading of biomass pyrolysis vapors: catalyst screening on a fixed bed reactor, Bioresour. Technol. 102 (17) (2011) 8261e8267. [16] H.J. Park, J.I. Dong, J.K. Jeon, K.S. Yoo, J.H. Yim, J.M. Sohn, Y.K. Park, Conversion of the pyrolytic vapor of radiata pine over zeolites, J. Ind. Eng. Chem. 13 (2007) 182e189. [17] B. Valle, A.G. Gayubo, A.T. Aguayo, M. Olazar, J. Bilbao, Selective production of aromatics by crude bio-oil valorization with a nickel-modified HZSM-5 zeolite catalyst, Energy Fuels 24 (3) (2010) 2060e2070. [18] I.A. Aldobouni, A.B. Fadhil, I.K. Saied, Conversion of De-oiled castor seed cake into bio-oil and carbon adsorbents, Energy Sources Part A 37 (24) (2015) 2617e2624. [19] N.A.V. Santos, Z.M. Magriotis, A.A. Saczk, G.T.A. F assio, S.S. Vieira, Kinetic study of pyrolysis of castor beans (Ricinuscommunis L.) presscake: an alternative use for solid waste arising from the biodiesel production, Energy Fuels 29 (4) (2015) 2351e2357. [20] http://www.nrel.gov/docs/gen/fy13/42618.pdf. [21] http://www.nrel.gov/docs/gen/fy08/42619.pdf. [22] G. Merkouropoulos, A. Kapazoglou, V. Drosou, E. Jacobs, A. Krozlig, C. Papadopoulos, et al., Dwarf hybrids of the bioenergy crop Ricinus communis suitable for mechanized harvesting reveal differences in morphophysiological characteristics and seed metabolic profiles, Euphytica (2016 May), http://dx.doi.org/10.1007/s10681-016-1702-6. [23] C. Michailof, T. Sfetsas, S. Stefanidis, K. Kalogiannis, G. Theodoridis, A. Lappas, Quantitative and qualitative analysis of hemicellulose, cellulose and lignin bio-oils by comprehensive two-dimensional gas chromatography with timeof-flight mass spectrometry, J. Chromatogr. A 1369 (November) (2014) 147e160.
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001
K.G. Kalogiannis et al. / Biomass and Bioenergy xxx (2016) 1e11 [24] E. Alexopoulou, Y. Papatheohari, F. Zanetti, K. Tsiotas, I. Papamichael, M. Christou, et al., Comparative studies on several castor (Ricinus communis L.) hybrids: growth, yields, seed oil and biomass characterization, Ind. Crops. Prod. 75 (August) (2015) 8e13. [25] J.B. Sluiter, R.O. Ruiz, C.J. Scarlata, A.D. Sluiter, D.W. Templeton, Compositional analysis of lignocellulosic feedstocks. 1. Review and description of methods, J. Agric. Food Chem. 58 (16) (2010) 9043e9053. [26] K.H. Kim, jy Kim, T.S. Cho, J.W. Choi, Influence of pyrolysis temperature on physicochemical properties of biochar obtained from the fast pyrolysis of pitch pine (Pinus rigida), Bioresour. Technol. 118 (August) (2012) 158e162. [27] S. Sensoz, D. Angin, Pyrolysis of safflower (Charthamus tinctorius L.) seed press cake: part 1. The effects of pyrolysis parameters on the product yields, Bioresour. Technol. 99 (13) (2008) 5492e5497. lez, J. Gonz [28] J.M. Encinar, J.F. Gonza alez, Fixed-bed pyrolysis of Cynara cardunculus L. product yields and compositions, Fuel Process Technol. 68 (3) (2000) 209e222. [29] T. Sfetsas, C. Michailof, A. Lappas, Q. Li, B. Kneale, Qualitative and quantitative analysis of pyrolysis oil by gas chromatography with flame ionization detection and comprehensive two-dimensional gas chromatography with time-offlightmass spectrometry, J. Chromatogr. A 1218 (2011) 3317e3325. [30] E. Doumer, G.G.C. Arízaga, Da Silva da, C.I. Yamamoto, E.H. Novotny, J.M. Santos, et al., Slow pyrolysis of different Brazilian waste biomasses as sources of soil conditioners and energy, and for environmental protection, J Anal. Appl. Pyr. 113 (2015) 434e443. [31] B. Vishwanadham, R.H. Sripathi, D. Sadasivudu, A.A. Khan, Pyrolysis of castor oil methylesters to 10-undecenoic acid and heptaldehyde, Indian J Chem. Technol. 2 (1995) 119e128. [32] g Das, rk Trivedi, A.K. Vasishtha, Heptaldehyde and undecylenic acid from
11
Castor oil, J Am. Oil Chem. Soc 66 (1989) 938e941. [33] P. Biller, A.B. Ross, Potential yields and properties of oil from the hydrothermal liquefaction of microalgae with different biochemical content, Bioresour. Technol. 102 (1) (2011) 215e225. [34] R.V.S. Silva, A. Casilli, A.L. Sampaio, B.M.F. Avila, M.C.C. Veloso, D.A. Azevedo, G.A. Romeiro, The analytical characterization of castor seed cake pyrolysis biooils by using comprehensive GC coupled to time of flight mass spectrometry, J. Anal. Appl. Pyr. 106 (March) (2014) 152e159. € holm, Py[35] K.G. Kalogiannis, S.D. Stefanidis, C.M. Michailof, A.A. Lappas, E. Sjo rolysis of lignin with 2DGC quantification of lignin oil: effect of lignin type, process temperature and ZSM-5 in situ upgrading, J Anal. Appl. Pyr. 115 (September) (2015) 410e418. [36] E.F. Iliopoulou, S.D. Stefanidis, K.G. Kalogiannis, A. Delimitis, A.A. Lappas, K.S. Triantafyllidis, Catalytic upgrading of biomass pyrolysis vapours using transition metal-modified ZSM-5 zeolite, Appl. Catal. B Environ. 127 (October) (2012) 281e290. [37] J. Adam, M. Blazso, E. Meszaros, M. Stocker, M. Nilsen, A. Bouzga, et al., Pyrolysis of biomass in the presence of Al-MCM-41 type catalysts, Fuel 84 (12e13) (2005) 1494e1502. [38] J. Adam, E. Antonakou, A. Lappas, M. Stocker, M.H. Nilsen, A. Bouzga, In situ catalytic upgrading of biomass derived fast pyrolysis vapours in a fixed bed reactor using mesoporous materials, Microporous Mesoporous Mater. 96 (1e3) (2006) 93e101. [39] E. Antonakou, A. Lappas, M.H. Nilsen, A. Bouzga, M. Stocker, Evaluation of various types of Al-MCM-41 materials as catalysts in biomass pyrolysis for the production of bio-fuels and chemicals, Fuel 85 (14e15) (2006) 2202e2212. [40] M.A. Jackson, D.L. Compton, A.A. Boateng, Screening heterogeneous catalysts for the pyrolysis of lignin, J Anal. Appl. Pyr. 85 (2009) 226e230.
Please cite this article in press as: K.G. Kalogiannis, et al., Castor bean cake residues upgrading towards high added value products via fast catalytic pyrolysis, Biomass and Bioenergy (2016), http://dx.doi.org/10.1016/j.biombioe.2016.07.001