Pyrolysis vapors, upgrading

The yield of products from catalytic pyrolysis depends on catalyst type and catalyst to feed ratios besides pyrolysis temperature and residence time (Ojha and Vinu, 2015). Different types of catalysts have different properties such as surface acidity, specific surface area, pore size, and pore size distributions which also determine the yield and selectivity of various products. The range of different functionalities of the catalysts should be matched to the various pyrolysis feedstocks as each feedstock may have a preferred pyrolysis catalyst. Therefore research has been precise in developing particular catalysts for specific raw material (depending on pyrolysis reactor). The section below describes the properties and effect specific catalysts have on pyrolysis vapor upgrading. 

Diebold, J.P. Scahill, J.W. "Biomass to gasoline (BTG) upgrading pyrolysis vapors to aromatic gasoline with zeolite catalysts at atmospheric pressure." In This Volume. 

Upgrading Pyrolysis Vapors to Aromatic Gasoline with Zeolite Catalysis at Atmospheric Pressure... 

Catalytic upgrading of pyrolysis oils or in situ catalytic upgrading of pyrolysis vapors can be carried out to provide mixtures of potential value as chemical feedstocks. Wheat straw hgnin was converted to ethylbenzene in a two-step sequence, first via pyrolytic depolymerization over a composite Re-Y/HZSM-5 (25) catalyst and subsequent conversion to ethylbenzene via treatment with EtOH... 

Aho, A., Kumar, N., Lashkul, A. V, Eranen, K., Ziolek, M., Decyk, P, Salmi, T, Holmbom, B., Hupa, M., Murzin, D. Y. Catalytic upgrading of woody biomass derived pyrolysis vapors over iron modified zeolites in a dual-fluidized bed reactor. Fuel 2010, 89,... 

To begin, we discuss the upgrading of bio-oils by means of cracking and hydrodeoxygenatioa This will be followed by upgrading pyrolysis vapors and cataljdic pyrolysis. Finally, a short overview of catalytic fast pyrolysis of lignin will close this part of the chapter. 

Examination of the catalytic properties of catalysts in the upgrading of pyrolysis vapors is regularly performed in a fixed-bed configuration, in which the biomass substrate and catalyst bed are separated and the pyrolysis vapors are driven over the catalyst bed by an inert gas flow. 

Studied [269,272,273], Both ZSM-5 catalysts emerge as the best catalysts with the highest yields of hydrocarbon products and lowest coke formation [269], The aromatics yield tends to decrease in the order ZSM-5 >H-beta>H-mordenite>H-ferrierite/HY [273], Stefanidis et al. demonstrated that, in comparison to a range of amorphous catalysts such as alumina, zirconia/ titania, and magnesium oxide, ZSM-5 is more suitable for the reduction of undesirable compounds and production of aromatics in the upgrading of pyrolysis vapors from beech wood [274], The excellent performance of ZSM-5 is attributed to the important role of its medium pore size [269], Besides, Park et al. pointed out that ZSM-5 is more efficient than Y zeolites due to the proper distribution of strong acid sites [275],... 

During the in-bed catal54ic fast pyrolysis, the pyrolysis is carried out in the direct presence of the zeolite, that is the substrate and the catalyst are in physical contact during pyrolysis. Compared to cataljdic upgrading of pyrolysis vapors, the zeolite impact in catalytic fast pyrolysis is much higher due to a better contact of the substrate and intermediates with the zeoUte. A disadvantage of catalytic fast pyrolysis is the higher coke deposition on the... 

Similar to the upgrading of pyrolysis vapors, the effect of metal incorporation was extensively studied. Hicks et al. tested ZSM-5, hierarchical ZSM-5 (meso-ZSM-5, synthesized using a dry-gel method followed by steam-assisted crystallization), and their Ce-incorporated analogues in the catalytic pyrolysis of glucose at 600°C [291]. ZSM-5 and Ce/ZSM-5 yielded mainly aromatics, while meso-ZSM-5 and especially Ce/meso-ZSM-5 exhibited product distributions greatly shifted from aromatics to oxygenated chemicals like aldehydes, furans. 

Diebold J, ScahiU J. Biomass to gasoline—upgrading pyrolysis vapors to aromatic gasoline with zeolite catalysis at atmospheric-pressure. ACS Symp Ser 1988 376 264—76. 

Home PA, WiUiams PT. The effect of zeolite ZSM-5 catalyst deactivation during the upgrading of biomass-derived pyrolysis vapors. J Anal Appl Pyrolysis 1995 34 65-85. 

Stefanidis SD, Kalogiannis KG, lliopoulou EE, Lappas AA, Pilavachi PA. In-situ upgrading of biomass pyrolysis vapors catalyst screening on a fixed bed reactor. Bioresour Technol 2011 102 8261-7. 

Iliopoulou EF, Stefanidis SD, Kalogiannis KG, Debmitis A, Lappas AA, Triantafybidis KS. Catalytic upgrading of biomass pyrolysis vapors using transition metal-modified ZSM-5 zeobte. Appl Catal B 2012 127 281-90. 

In the process of the catalytic conversion of biomass to biooil, the incorporation of different types of metals such as Bi, Ce, Co, Cu, Fe, Ga, Na, and Ni into the catalysts can play a very important role. Among the different metals Ni has been shown to display the best activities in combination with a ZSM-5 catalyst for the conversion of oxygenated compounds to hydrocarbon species (French and Czemik, 2010). Studies on the catalytic upgradation of pyrolysis vapor obtained from biomass have shown that the product composition may depend on the nature of the catalyst. 

Kaewpengkrow, P., Atong, D., Sricharoenchaikul, V., 2014. Catalytic upgrading of pyrolysis vapors from Jatropha wastes using alumina, zirconia and titania based catalysts. Bioresource Technology 163, 262—269. 

Pyrolysis vapors are directly upgraded without bio-oil condensation and vaporizing processes ... 

Lu, Q., et al., 2010a. Catal3dic upgrading of biomass fast pyrolysis vapors with nano metal oxides an analytical py-GC/MS study. Energies 3 (11), 1805. 

Veses, A., et al., 2015. Catal3dic upgrading of biomass derived pyrolysis vapors over metal-loaded ZSM-5 zeolites effect of different metal cations on the bio-oH final properties. Microporous and Mesoporous Materials 209 (0), 189—196. 

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