Upgrading of wood pyrolysis

Chen, N.Y. Walsh, D.E. Koenig, L.R. "Fluidized bed upgrading of wood pyrolysis liquids and related compounds." In This Volume. 

Fluidized-Bed Upgrading of Wood Pyrolysis Liquids and Related Compounds... 

Low-Pressure Upgrading of Vacuum-Pyrolysis Oils from Wood... 

Renaud M, Giandmaison JL, Roy C, Ktiliaguine S. 1988. Low pressure upgrading of vacuum-pyrolysis oils from wood. In Soltes EJ, Milne TA (editors). Pyrolysis Oils from Biomass. American Chemictil Society Symposium Series 376. American Chemictil Society. 

Meier D., Wehlte S., Wulzinger P. Faix O. (1996) Upgrading of bio-oils and flash pyrolysis of CCB-treated wood waste. In Bio-oil Production and Utilization-Proceedings of the 2nd EU-Canada Workshop on Thermal Processing. (Ed. by Bridgwater AV Boocock DGB) CPL Press, UK, pp. 1402-1412... 

DeGroot, W.F. Pan, W-P. Rahman, M.D. Richards, G.N. "Esurly products of pyrolysis of wood." In Production. Analysis and Upgrading of Oils from Biomass. Vorres, K.S., Ed., American Chemical Society, Division of Fuel Chemistry Abstracts, 1987, 32(2). 36. 

Laboratory (4) and Process Development Unit (5,6) studies originally conducted at the Universite de Sherbrooke, and now conducted jointly with the private industry at Universite Laval, province of Quebec, have led to the conclusion that thermal decomposition under reduced pressure is an attractive approach for the conversion of biomass into chemicals and fuels products. The process uses a multiple-hearth furnace for wood pyrolysis. This approach is characterized by a low pressure and a short residence time of the vapor products in the rciactor. When compared with conventional, atmospheric pressure carbonization, vacuum pyrolysis has the potential to significantly enhance the yields of organic liquid products with respect to solid and gaseous products. The pyrolysis oils (biooils) obtained from this process can be deoxygenated into transportation fuels upon further upgrading (7). Specialty as well as commodity (Pakdel, H. Roy, C. Biomass, in press) chemicals can also be extracted from the pyrolysis oil product. 

Figure 2 shows the products obtained in a scheme in which direct upgrading of the wood pyrolysis liquids over ZSM-5 occurs in parallel with upgrading of methanol obtained from synthesis gas derived from gasification of the pyrolysis char. In Figure 3, the methanol is mixed with the pyrolysis liquids prior to co-processing over ZSM-5. Approximately 40 lbs. of methanol per 100 lbs. of dry wood feed is potentially available from the char and pyrolysis gas products. 

Stated differently, without char gasification, only about 6% of the carbon in the wood could be upgraded to hydrocarbon products even if all the oxygenates produced by pyrolysis were recycled to extinction. Parallel upgrading of methanol derived from char gasification can increase this value to approximately 36%, i.e., about 6% from the pyrolysis liquids and 30% from methanol. Methanol co-processing boosts the percent of wood carbon transformed into... 

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],... 

Pyrolysis oil (bio-oil) is produced in fast and flash pyrolysis processes and can be used for indirect co-firing for power production in conventional power plants and potentially as a high energy density intermediate for the final production of chemicals and/or transportation fuels. Gas chromatographic analysis of the liqtrid fraction of pyrolysis products from beech wood is given in Table 3.6 (Demirbas, 2007). Biocmde resrrlts from severe hydrothermal upgrading (HTU) of relatively wet biomass and potentially can be used for the production of materials, chemicals,... 

The overall conclusion is that pyrolysis liquid may be produced and fired at the same cost level as pellets from wood. At present though, development work on pyrolysis liquid has to secure an acceptable and even quality of the upgraded wood fuel as far as that of pellets. 

Many biomass pyrolysis processes convert 55%-65% of dry biomass to a very inexpensive pyrolysis oil (1-3). Costs of the oils will range from 0.02- 0.08/lb of oil, depending on the biomass feedstock cost ( 10- 40/dry ton biomass). Therefore, these inexpensive oils, rich in phenolic fractions, acids, and furan-derivatives could be feedstocks for further upgrading or could be used because of their reactivity, in applications such as thermosetting resins and other wood-bonding methods. One of the... 

The oil fractions collected on the six hearthes of a wood vacuum pyrolysis process demonstration unit have been upgraded to hydrocarbons in the C5-C10 range on a ZSM-5 catalyst. The use of a precoker at reaction temperature has been demonstrated and C5-Ci 0 hydrocarbons yields of the order of 30 wt% of oil fed, have been reached. GC/FTIR analyses of the heavier liquids collected after the precoker indicate that the acids in the oils play a dominant role in the gas phase reactions occurring in the precoker. 

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