Abstract
Bio-oil from the pyrolysis of biomass is an important renewable source for liquid fuel. However, the application of bio-oil has been severely restricted due to its high viscosity, acidity, and low heating value. Thus, it has been necessary to upgrade bio-oil for automobile fuel via catalytic deoxygenation reactions. Herein, the effects of the zeolite ZSM-5 on the pyrolysis of four biomass materials (corn cob, corn straw, pine powder, and cellulose) were investigated via TG-FTIR (thermogravimetric analyzer coupled with a Fourier transform infrared spectrometer) to better understand the working mechanism of ZSM-5. The contents of the products of H2O, CO, CO2, and the C-O, C=O, and OH groups evolved with increasing pyrolytic temperature were monitored by FTIR. It was found that the relative contents of the C-O and C=O groups were decreased under the catalysis of ZSM-5, while the formations of CO, H2O, and the OH containing compounds were promoted. To explain the regulations, reaction routes were speculated and the catalytic conversion mechanisms were deduced.
Download PDF
Full Article
Influence of the Zeolite ZSM-5 on Catalytic Pyrolysis of Biomass via TG-FTIR
Ze Wang,* Siwei Liu, Weigang Lin, and Wenli Song
Bio-oil from the pyrolysis of biomass is an important renewable source for liquid fuel. However, the application of bio-oil has been severely restricted due to its high viscosity, acidity, and low heating value. Thus, it has been necessary to upgrade bio-oil for automobile fuel via catalytic deoxygenation reactions. Herein, the effects of the zeolite ZSM-5 on the pyrolysis of four biomass materials (corn cob, corn straw, pine powder, and cellulose) were investigated via TG-FTIR (thermogravimetric analyzer coupled with a Fourier transform infrared spectrometer) to better understand the working mechanism of ZSM-5. The contents of the products of H2O, CO, CO2, and the C-O, C=O, and OH groups evolved with increasing pyrolytic temperature were monitored by FTIR. It was found that the relative contents of the C-O and C=O groups were decreased under the catalysis of ZSM-5, while the formations of CO, H2O, and the OH containing compounds were promoted. To explain the regulations, reaction routes were speculated and the catalytic conversion mechanisms were deduced.
Keywords: Biomass; Catalysis; Upgrading; Mechanism; ZSM-5
Contact information: State Key Laboratory of Multi-Phase Complex System, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China;
* Corresponding author: wangze@home.ipe.ac.cn
INTRODUCTION
Bio-oil from the pyrolysis of biomass is an important renewable source for liquid fuel and/or for chemicals (Huber et al. 2006; Mohan et al. 2006; Bridgwater 2012). However, the application of bio-oil has been severely restricted due to its high viscosity and acidity and low heating value. Thus, efforts had been made to upgrade bio-oil for use as an automobile fuel via catalytic deoxygenation reactions (Williams and Horne 1995; Vitolo et al. 1999; Nokkosmaki et al. 2000; Thring et al. 2000; Williams and Nugranad 2000; Karagöz et al. 2005; Adam et al. 2006; Antonakou et al. 2006; Huber et al. 2006; Nilsen et al. 2007; Triantafyllidis et al. 2007; Song et al. 2010; Vispute et al. 2010; Stefanidis et al. 2011; Stephanidis et al. 2011; Campanella and Harold 2012). The investigations focused on zeolites due to their relatively greater effect and lower cost (Williams and Horne 1995; Vitolo et al. 1999; Thring et al. 2000; Williams and Nugranad 2000; Adam et al. 2006; Antonakou et al. 2006; Nilsen et al. 2007; Triantafyllidis et al. 2007; Vispute et al. 2010; Stefanidis et al. 2011; Stephanidis et al. 2011; Campanella and Harold 2012).
The Li research group (Fan et al. 2013; Gong et al. 2011; Huang et al. 2012) had systematically investigated the effect of La/HZSM-5 catalyst on producing light olefins from conversions of various biomass materials such as cellulose, hemicellulose, lignin, rice husk, sawdust, sugarcane bagasse, and bio-oil as well. It was found that the biomass with higher content of cellulose or hemicellulose generated more olefins than those with higher content of lignin, and the addition of lanthanum played an important role in promoting the formation of olefins. Additionally, the effect of current on transformation of bio-oil to BTX by catalysis of HZSM-5 was also investigated (Bi et al. 2013), and the results revealed that the methoxy, hydroxyl, and methyl groups in aromatics could be effectively removed in the current-enhanced catalytic process. Stephanidis et al. (2011) investigated the effect of ZSM-5 on the pyrolysis of beech wood before and after hydrothermal pretreatment. It was found that under the catalysis of ZSM-5, the contents of H2O and CO were increased significantly, while the content of CO2 was decreased distinctly for both raw and pretreated beech wood. The contents of the C=O containing components (acids, aldehydes, and ketones) were decreased remarkably under ZSM-5 catalysis in both systems; the content of esters was increased in the raw beech wood system but remained almost unchanged in the pretreated system. For components containing C-O-C bonds, the furan content was increased in both of the raw and pretreated systems; the content of other ethers was only increased by a modest degree in the raw beech wood system but was decreased remarkably in the pretreated system. For the components containing C-OH bond, the content of phenols was decreased, but the content of alcohols was increased for both systems. The formation of aromatics was promoted obviously in both systems. In the Williams’ work (Williams and Horne 1995), the contents of H2O, CO, and CO2 were all increased remarkably during the pyrolysis of wood waste via ZSM-5 catalysis. However, for the pyrolysis of Lignocel HBS 150-500, Stefanidis et al. (2011) observed that the CO content was increased, the CO2 content changed very little, and the generation of H2O was only weakly promoted by ZSM-5 catalysis. The concentration of acids, aldehydes, and ketones were decreased remarkably, but esters were more generated under the catalysis of high surface area of ZSM-5. Phenols and alcohols were more generated. The concentration of furans was decreased under the catalysis of low surface area of ZSM-5, but increased by high surface area of ZSM-5. Campanella and Harold (2012) investigated the pyrolysis of chlorella under the catalysis of ZSM-5 and the results were found similar to those obtained by Stefanidis et al. (2011), in that the CO content was remarkably increased and the CO2 content changed very little, though H2O was promoted more distinctly and the alcohol content decreased slightly.
As previous investigations illustrated, the extent of the catalytic effects varied with different biomass resources and with different reaction conditions. Furthermore, the problems of short catalyst life-time and poor reproducibility hindered the industrial applications of zeolites severely, and the reasons for the problems were vague. Thus, it was worthwhile to investigate the working mechanisms of zeolites to improve their effects.
In this paper, the effect of ZSM-5 zeolite on the pyrolysis of four biomass materials of corn cob (CC), corn straw (CS), pine powder (PN), and cellulose (CE) were investigated via a thermogravimetric analyzer (TG) coupled with a Fourier transform infrared spectrometer (FTIR). The compounds containing C-O, C=O, and OH groups and the products of H2O, CO, and CO2 evolved with increasing temperature were monitored by FTIR to better understand the catalytic mechanism.
EXPERIMENTAL
An instrument of thermogravimetric analyzer (Netzsch 449C, Germany) coupled with a Fourier transform infrared spectrometer (Bruker Equinox 55, America) was used in this research. Biomass samples were pyrolyzed in the TG analyzer, and the pyrolytic volatiles were carried away by a carrier gas of pure N2 (60 mL/min) through a transfer line to a gas cell for IR analysis. All samples were heated from 40 °C to 900 °C at 30 °C/min in the pyrolysis zone, and the transfer line and gas cell were kept at 210 °C. In each run, 12 mg of a biomass sample was loaded into a crucible, and the amount of ZSM-5 used was about 3 mg. The IR spectrometer scanned from 400 to 4000 cm-1, and a spectrum was obtained every 32 scans.
RESULTS AND DISCUSSION
TG Analysis
The TG and DTG curves of CC, CS, PN, and CE are shown in Fig. 1. The figure shows that the pyrolysis of CC and CS started at about 200 °C, the initial pyrolytic temperature of PN followed at around 250 °C, and CE started the pyrolytic process at about 300 °C. Consequently, the main pyrolytic processes of CS and CC ended earlier at about 380 °C, and those of PN and CE ended later at around 420 °C. As shown in the DTG curves, two weight loss peaks can be identified in the CC, CS, and PN curves, while only one peak appears in the CE curve.
As previous investigations illustrated (Wang et al. 2011; Zhou et al. 2013), for biomass materials, the initial pyrolysis of hemicellulose was early, cellulose started the pyrolysis later and proceeded fastest within a narrow temperature range, and lignin pyrolyzed slowly in a broad temperature range with a low initial pyrolytic temperature. Therefore, the first DTG peak was attributed to the pyrolysis of hemicellulose, and the second peak was due to cellulose. The short and broad DTG peak of lignin always overlapped the peaks of hemicellulose and cellulose, influencing the shapes of the first two peaks. Herein, the first peak (Peak 1) of CC was sharpest, the Peak 1 of CS was of average intensity, and the Peak 1 of PN was bluntest. By comparison with the typical TG and DTG curves of these three main biomass components, it could be deduced that hemicellulose was more abundant in CC and CS than in PN, while PN was richer in cellulose and lignin.
Very little difference could be identified in the initial pyrolytic temperatures in the TG curves or the peak positions in the DTG curves between the catalytic and non-catalytic systems. This result indicated that ZSM-5 did not remarkably promote or inhibit the primary pyrolysis of the biomass samples under the experimental conditions and instead might mainly influence the secondary reactions of the pyrolytic products, when the released volatiles contacted the surface of the catalyst. This was similar to the phenomena as reported by Güngör et al. (2012), where the pyrolysis of pine bark under the catalysis of ReUS-Y was conducted by TG analysis.
Fig. 1. TG and DTG curves from the pyrolysis of CC, CS, PN, and CE (black curve: non-catalytic pyrolysis of biomass; red curve: catalytic pyrolysis of biomass).
IR Analysis
Spectra from the pyrolysis of pure biomass materials
The IR spectra of the volatiles produced by the pyrolysis of solo biomass materials as pyrolytic temperature increased are shown in Fig. 2. The spectrum bands of major products and chemical groups are listed in Table 1. Figure 2 shows that the products of CO, CO2, H2O, and the groups of C-O, C=O, and OH could be accurately identified, and the release of the volatiles began steeply and proceeded rapidly. The carbonyl compounds and CO2, were two of the most abundant components in all volatile systems. The C=O signal was much stronger than that of CO2 in the PN and CE systems, while in the CC and CS systems much more CO2 was generated.
Table 1. Spectral Bands Assigned for Major Products, Chemical Groups (cm-1)
Fig. 2. IR spectra of the pyrolysates evolved from solo biomass materials with increasing pyrolytic temperature
Effect of ZSM-5 catalysis on the pyrolysis reaction
The ratio between the transmission intensity of a certain spectrum band and the total transmission intensity of the whole spectrum band (restricted from 950 cm-1 to 4000 cm-1 to erase the interference of significant noise at wavenumbers lower than 950 cm-1), was used for comparison between the catalytic and non-catalytic systems. Absolute IR values may be influenced by many uncertain factors, such as the differences of the sample amount for TG analysis, baseline drifting of IR signals, variations in the transparency of the glasses (ZnSe and KBr) in the gas cell after a period of usage, etc. These factors may cause absolute IR values to vary irregularly, creating difficulties when comparing between systems with tiny changes. Thus, the relative contents of components expressed as transmission percentages are more suitable for comparison between the catalytic and non-catalytic systems. The changes in the transmission percentages with increasing pyrolytic temperature are shown in Fig. 3. In Fig. 3, a lower percentage value means an increased relative content of the component, as a higher content of a component induces a weaker permeability to its IR signal.
Figure 3 illustrates that, for the four biomass pyrolytic systems, the transmission percentages of the compounds containing C-O and C=O groups under catalysis were all higher than those in the non-catalytic systems, while the percentages of CO, OH, and H2O were decreased under the catalysis of ZSM-5. The value of CO2 changed very little between the catalytic and non-catalytic systems. These trends signified that the contents of C-O and C=O groups were decreased under the catalysis of ZSM-5. The formation of CO, H2O, and the OH containing compounds were promoted, and the CO2 content remained relatively stable. Considering the relations between the promoted and inhibited components under catalysis, it could be deduced that the compounds containing C-O or C=O groups were partially converted to CO, H2O, and the OH containing compounds by partial removal of the oxygen atom from the pyrolytic liquid; thus, the oxygen content was decreased under catalysis. The generated water may occupy the active Lewis acid sides on the surface of the catalyst, and the Bronsted acid may be consumed as the reaction proceeds, explaining the deactivation of the catalyst.
Fig. 3 (Part 1). Transmission percentages of some components changed with increasing temperature (black curve: non-catalytic pyrolysis of biomass; red curve: catalytic pyrolysis of biomass)
Fig. 3 (Part 2). Transmission percentages of some components changed with increasing temperature (black curve: non-catalytic pyrolysis of biomass; red curve: catalytic pyrolysis of biomass)
Comparison with Literature for Analysis
The effect of ZSM-5 may differ in manner or extent due to different biomass materials or reaction conditions. Thus, some literature results were collected for comparison among each other and with the present results, as listed in Table 2.
Through the comparison among the literature results, the pyrolysis of the biomass materials exhibited a common trend of increased contents of CO, H2O, and aromatics, and decreased acid, aldehyde, and ketone contents under ZSM-5 catalysis. In general, the sum of acids, aldehydes, and ketones comprised the majority of the C=O containing components, so the C=O content should be decreased under catalysis whether the content of esters was increased or reduced. The effects of ZSM-5 on the contents of CO2, esters, furans, ethers, and phenols varied with different raw materials and reaction conditions.
In the present work, the increased contents of CO and H2O and the decreased C=O content were in accordance with the common trends; the CO2 content changed very little, which was not unusual compared to the decreased, increased, or stable CO2 contents reported in the literature. The IR analysis can instantaneously provide information on chemical group distribution of a mixture, but it can hardly identify single organic compounds as done by GC/MS, due to the severe overlaps of too many peaks in the complex mixtures. However, it is still possible to deduce some chemical conversions according to the increased and decreased contents of chemical groups. As deduced in formulas (1) and (2), CO2 is mainly derived from carboxylic acids and CO is mainly derived from the carbonyl groups of aldehydes and ketones. CO may also be generated from carboxylic acids with the formation of alcohols (or H2O) as by-products. The promoting effect of ZSM-5 on the conversions of aldehydes or ketones to CO is supported by the increased content of CO for all materials under all conditions. If the promoting effect of ZSM-5 on the conversion of carboxylic acids to CO2 is more distinct, the content of CO2 is to be increased; if the conversion of carboxylic acids to CO and OH is more pronounced, the CO2 content may be reduced and the CO and OH (or H2O) contents may be increased; if the promoting and inhibiting effect of ZSM-5 on the formation of CO2 behaves in similar degree, the CO2 content may change very little.
The products of H2O and the OH containing compounds may not only be derived from carboxylic acids as mentioned in formula (1) but may also be generated from the C-O containing compounds as showed in formula (3).
Table 2. Effect of ZSM-5 on Reported Product Distributions
Notes: [A]- Stephanidis et al. 2011; [B]- Williams et al. 1995; [C]- Stefanidis et al. 2011; [D]- Campanella and Harold 2012; BW- beech wood; HTBW- hydrothermal treated beech wood; WW- wood waste; LC- Lignocel HBS 150-500; CR- chlorella; ar- aromatics; ac- acids; al- aldehydes; ke- ketones; es- esters; ah- alcohols; fu- furans; et- ethers; ph- phenols; ↑- increased; ↓- reduced; ↑↓ -increased or reduced depends on surface area of catalyst; ≈- in similar level.
The decreasing extents of C-O and C=O in the CC, CS, and PN systems were much more significant than those in the CE system, indicating a poor catalytic activity of ZSM-5 on pure cellulose. The enhanced conversions of the CC, CS, and PN samples could be attributed to the inherent catalytic effects of ash materials (Bridgwater 2012) and the interactions among the various components.
Mechanism Discussion
A possible catalytic mechanism for the conversion from C=O to CO and from C-O to OH (or H2O) was speculated, as shown in Fig. 4 and Fig. 5. In the two figures, the model formula of zeolite was a simplified form of the one used in the book of Industrial Catalysis (Tang et al. 2010). In the conversion route from C=O to CO, the C=O group first adsorbs onto the surface of ZSM-5 via the interaction between the O atom of the C=O group and the Lewis acid site on Al atom. Then, some electrons from the O atom may move close to the C atom, which may promote the scission of the C-C bond to form an adsorbed R1– on the surface of ZSM-5 that is stabilized by the Lewis acid site. In the following steps, some electrons from R2 may shift to the C atom of the C=O group, which causes the release of CO and forms an adsorbed R2+ on the O atom of ZSM-5. The adsorbed R1– and R2+ may combine together further and generate a new R1-R2 compound, or they may react with any other free radicals to form other products.
Fig. 4. Catalytic reaction routes from C=O to CO
In the route from C-O to OH or to H2O, the O atom of the C-O-C(H) group may first adsorb onto the surface of ZSM-5 at the Lewis acid site, and a hydrogen bond may be generated between the O atom of ZSM-5 and the β-H of the organic compound. The ethers or alcohols are then converted to alkenes by the β-H elimination reaction.
Fig. 5. Catalytic reaction routes from C-O to OH (or H2O)
CONCLUSIONS
1. The C=O signal was much stronger than that of CO2 in the pyrolysates of PN and CE, while in the CC and CS systems much more CO2 was generated.
2. The contents of the C-O and C=O containing components were decreased under the catalysis of ZSM-5, the formations of CO, H2O, and the OH containing compounds were promoted, and the content of CO2 remained relatively stable.
3. It was deduced that carboxylic acids may be converted to CO2, or to CO and alcohols (or H2O). CO may also be derived from aldehydes or ketones. The C-O-C(H) group may be converted to H-O-C(H) to generate alcohols or H2O during ZSM-5 catalysis.
4. In the conversion route from C=O to CO, the adsorption of C=O onto the surface of ZSM-5 via the interaction between the O atom of the C=O group and the Lewis acid site on Al atom, is probably the first catalytic activation step.
5. In the route from C-O to OH or to H2O, the adsorption of the O atom of the C-O-C(H) group onto the surface of ZSM-5 at the Lewis acid site and the formation of a hydrogen bond between the O atom of ZSM-5 and the 
of the organic compound may be the key activation steps.
ACKNOWLEDGMENTS
The authors are grateful for the support from the National Natural Science Fund (51476180) and (91434105).
REFERENCES CITED
Adam, J., Antonakou, E., Lappas, A., Stocker, M., Nilsen, M. H., Bouzga, A., Hustad, J. E., and Oye, G. (2006). “In situ catalytic upgrading of biomass derived fast pyrolysis vapours in a fixed bed reactor using mesoporous materials,” Micropor. Mesopor. Mat. 96 (1-3), 93-101. DOI:10.1016/j.micromeso.2006.06.021
Antonakou, E., Lappas, A., Nilsen, M. H., Bouzga, A., and Stocker, M. (2006). “Evaluation of various types of Al-MCM-41 materials as catalysts in biomass pyrolysis for the production of bio-fuels and chemicals,” Fuel 85 (14-15), 2202-2212. DOI:10.1016/j.fuel.2006.03.021
Bi, P., Yuan, Y., Fan, M., Jiang, P., Zhai, Q., and Li, Q. (2013). “Production of aromatics through current-enhanced catalytic conversion of bio-oil tar,” Bioresour. Technol. 136, 222-229. DOI: 10.1016/j.biortech.2013.02.100
Bridgwater, A. V. (2012). “Review of fast pyrolysis of biomass and product upgrading,” Biomass Bioenerg. 38, 68-94. DOI:10.1016/j.biombioe.2011.01.048
Campanella, A., and Harold, M. P. (2012). “Fast pyrolysis of microalgae in a falling solids reactor: Effects of process variables and zeolite catalysts,” Biomass Bioenerg. 46, 218-232.DOI:10.1016/j.biombioe.2012.08.023
Fan, M., Jiang, P., Bi, P., Deng, S., Yan, L., Zhai, Q., Wang, T., and Li, Q. (2013). “Directional synthesis of ethylbenzene through catalytic transformation of lignin,” Bioresour. Technol. 143, 59-67. DOI: 10.1016/j.biortech.2013.05.097
Gong, F., Yang, Z., Hong, C., Huang, W., Ning, S., Zhang, Z., Xu, Y., and Li, Q. (2011). “Selective conversion of bio-oil to light olefins: Controlling catalytic cracking for maximum olefins,” Bioresour. Technol. 102, 9247-9254. DOI: 10.1016/j.biortech.2011.07.009
Güngör, A., Önenç, S., Uçar, S., and Yanik, J. (2012). “Comparison between the “one-step” and “two-step” catalytic pyrolysis of pine bark,” J. Anal. Appl. Pyrol. 97, 39-48. DOI: 10.1016/j.jaap.2012.06.011
Huang, W., Gong, F., Fan, M., Zhai, Q., Hong, C., and Li, Q. (2012). “Production of light olefins by catalytic conversion of lignocellulosic biomass with HZSM-5 zeolite impregnated with 6wt.% lanthanum,” Bioresour. Technol. 121, 248-255. DOI: 10.1016/j.biortech.2012.05.141
Huber, G. W., Iborra, S., and Corma, A. (2006). “Synthesis of transportation fuels from biomass: chemistry, catalysts, and engineering,” Chem. Rev. 106 (9), 4044-4098. DOI: 10.1021/cr068360d
Karagöz, S., Bhaskar, T., Muto, A., Sakata, Y., Oshiki, T., and Kishimoto, T. (2005). “Low-temperature catalytic hydrothermal treatment of wood biomass: Analysis of liquid products,” Chem. Eng. J. 108(1-2), 127-137. DOI:10.1016/j.cej.2005.01.007
Mohan, D., Pittman, C. U., and Steele, P. H. (2006). “Pyrolysis of wood/biomass for bio-oil: A critical review,” Energy & Fuels 20 (3), 848-889. DOI: 10.1021/ef0502397
Nilsen, M. H., Antonakou, E., Bouzga, A., Lappas, A., Mathisen, K., and Stocker, M. (2007). “Investigation of the effect of metal sites in Me-Al-MCM-41 (Me = Fe, Cu or Zn) on the catalytic behavior during the pyrolysis of wooden based biomass,” Micropor. Mesopor. Mat. 105(1-2), 189-203. DOI:10.1016/j.micromeso.2007.05.059
Nokkosmaki, M. I., Kuoppala, E. T., Leppamaki, E. A., and Krause, A. O. I. (2000). “Catalytic conversion of biomass pyrolysis vapours with zinc oxide,” J. Anal. Appl. Pyrol. 55 (1), 119-131. DOI:10.1016/S0165-2370(99)00071-6
Song, M., Zhong, Z., and Dai, J. (2010). “Different solid acid catalysts influence on properties and chemical composition change of upgrading bio-oil,” J. Anal. Appl. Pyrol. 89 (2), 166-170. DOI:10.1016/j.jaap.2010.07.007
Stefanidis, S. D., Kalogiannis, K. G., Iliopoulou, E. F., Lappas, A. A., and Pilavachi, P. A. (2011). “In-situ upgrading of biomass pyrolysis vapors: Catalyst screening on a fixed bed reactor,” Bioresource Technol. 102 (17), 8261-8267. DOI:10.1016/j.biortech.2011.06.032
Stephanidis, S., Nitsos, C., Kalogiannis, K., Iliopoulou, E. F., Lappas, A. A., and Triantafyllidis, K. S. (2011). “Catalytic upgrading of lignocellulosic biomass pyrolysis vapours: Effect of hydrothermal pre-treatment of biomass,” Catal. Today. 167 (1), 37-45. DOI:10.1016/j.cattod.2010.12.049
Tang, X., Wang, H., and Wang, F. (2010). “Solid acid and base catalysts,” Industrial Catalysis, Xu, Y., and Jin, J. (eds.), Chemical Industry Press, Beijing. Page 65.
Thring, R. W., Katikaneni, S. P. R., and Bakhshi, N. N. (2000). “The production of gasoline range hydrocarbons from Alcell(R) lignin using HZSM-5 catalyst,” Fuel Process Technol. 62 (1), 17-30. DOI:10.1016/S0378-3820(99)00061-2
Triantafyllidis, K. S., Iliopoulou, E. F., Antonakou, E. V., Lappas, A. A., Wang, H., and Pinnavaia, T. J. (2007). “Hydrothermally stable mesoporous aluminosilicates (MSU-S) assembled from zeolite seeds as catalysts for biomass pyrolysis,” Micropor. Mesopor. Mat. 99 (1-2), 132-139. DOI:10.1016/j.micromeso.2006.09.019
Vispute, T. P., Zhang H., Sanna, A., Xiao, R., and Huber, W. G. (2010). “Renewable chemical commodity feedstocks from integrated catalytic processing of pyrolysis oils,” Science 330(6008), 1222-1227. DOI: 10.1126/science.1194218
Vitolo, S., Seggiani, M., Frediani, P., Ambrosini, G., and Politi, L. (1999). “Catalytic upgrading of pyrolytic oils to fuel over different zeolites,” Fuel 78 (10), 1147-1159. DOI:10.1016/S0016-2361(99)00045-9
Wang, S., Guo, X., Wang, K., Luo, Z. (2011). “Influence of the interaction of components on the pyrolysis behavior of biomass,” J. Anal. Appl. Pyrol. 91 (1), 183-189. DOI: 10.1016/j.jaap.2011.02.006
Williams, P. T., and Horne, P. A. (1995). “The influence of catalyst regeneration on the composition of zeolite-upgraded biomass pyrolysis oils,” Fuel 74 (12), 1839-1851. DOI:10.1016/0016-2361(95)80017-C
Williams, P. T., and Nugranad, N. (2000). “Comparison of products from the pyrolysis and catalytic pyrolysis of rice husks,” Energy 25 (6), 493-513. DOI:10.1016/S0360-5442(00)00009-8
Zhou, H., Long, Y., Meng, A., Li, Q., and Zhang, Y. (2013). “The pyrolysis simulation of five biomass species by hemi-cellulose, cellulose and lignin based on thermogravimetric curves,” Thermochim. Acta566, 36-43. DOI: 10.1016/j.tca.2013.04.040
Article submitted: December 15, 2014; Peer review completed: May 15, 2015; Revised version received and accepted: May 25, 2015; Published: June 2, 2015.
DOI: 10.15376/biores.10.3.4485-4497