Catalysts, fast pyrolysis

Fast pyrolysis oil has almost the same elemental composition as the biomass itself hence it can be seen as a kind of liquid wood. It can be transported, can be pressurized and processed more easily than solid biomass. One of the major difficulties in the catalytic conversion of solid biomass is achieving effident con-tad between the heterogeneous catalyst (which is most of the times a solid) and the biomass itself. In this context, bio-oil provides more options for easier catalytic conversion. However, pyrolysis is a very complex and the oil is a difficult to handle chemical mixture. Complete vaporization, for instance, is not possible because part of the components start to decompose and polymerize upon heating... 

Char acts as an effective vapour cracking catalyst at fast pyrolysis reaction temperatures so rapid and effective char separation/elutriation is important,... 

Fast pyrolysis is a process with no need of oxygen that converts biomass into a mixture of low-molecular weight oxygenates to be subsequently cracked and steam reformed. A hydrogen yield of 80 % of the theoretical maximum has been obtained in experimental studies. The marketing of the byproducts seems possible. Focus of research is being laid upon the catalytic reforming step to minimize carbon formation on the catalyst [19, 67]. 

Pyrolysis vapors made by the fast pyrolysis of softwood are very reactive with ZSM-5 catalyst to form a liquid hydrocarbon product, which is similar to that formed from methanol. Although the catalyst is deactivated relatively quickly with pyrolysis vapors compared to methanol, experimentation indicates that the catalyst... 

Catalytic fast pyrolysis Re-USY, H-ZSM-5, P-zeolite Catalyst ensures further cracking of the pyrolysis intermediates and oxygen removal, resulting in the formation of hydrocarbons [61]... 

Cheng Y-T, Jae J, Shi J, Fan W, Huber GW (2012) Production of renewable aromatic compounds by catalytic fast pyrolysis of lignocellulosic biomass with bifiinctional Ga/ZSM-5 catalysts. Angew Chem Int Ed 51(6) 1387-1390... 

Wildschut J, Iqbal M, Mahfud FH, Cabrera IM, Venderbosch RH, Heeres HI (2010) Insights in the hydrotreatment of fast pyrolysis oil using a ruthenium on carbon catalyst. Energ Environ Sci 3(7) 962-970... 

Yu YQ, Li XY, Su L, Zhang Y, Wang YJ, Zhang HZ (2012) The role of shape selectivity in catalytic fast pyrolysis of lignin with zeolite catalysts. Appl Catal A 447 115... 

To conclude, bio-oU, the hquid product formed from fast pyrolysis of biomass, can be considered as one of the most promising renewable feedstocks for hydrogen or syngas production. Nevertheless, deactivation of catalysts often occurs during SR of biooil (Zhang et al., 2014), and the use of H2-selective membranes even increases this problem as the hydrogen is removed from the reaction side. 

CFP [Catalytic Fast Pyrolysis] A process for converting lignocellulosic biomass into a mixture of aromatic hydrocarbons, notably / -xylene. It uses a fluidized bed at 500°C-1000°C and a modified ZSM-5 zeolite catalyst. Invented by G.W. Huber and colleagues at the University of Massachusetts-Amherst and licensed through Anellotech. The first plant is scheduled for completion in 2014. 

Pattiya, A., Titiloye, J. O., Bridgwater, A. V. Fast pyrolysis of cassava rhizome in the presence of catalysts. J Anal Appl Pyrolysis 2008, 81, 72-79. 

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... 

A high aromatics selectivity, however, requires proper catalyst selection. Zhang et al. studied the fast pyrolysis of corncob in absence and presence of a catalyst (ie, ZSM-5) [287]. The presence of the catalyst increased the yields of noncondensable gas, water, and coke, while decreasing the liquid and char yields. The catalyst induced a decrease of the oxygen content of the liquid fraction by more than 25%. These studies indicate the importance of a catalyst during biomass pyrolysis. The most important catalytic parameters affecting the product distribution are pore structure and acid site type. This was demonstrated by testing siUcalite, a material with the same pore structure as ZSM-5 but with intrinsic different acid sites, and siUca-alumina, an amorphous material with Brpnsted acid sites, in the catalytic pyrolysis of... 

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