Lignocellulosic biomass pyrolysis

Value-Added Products from Lignocellulosic Biomass Pyrolysis... 

Lignocellulose biomass is a mixture of phenolic lignin and carbohydrates -cellulose and hemi-cellulose. It grows abundantly on earth and is largely available as agricultural and forestry residues. Lignocellulose can be converted via four major routes pyrolysis, gasification, hydrolysis and fermentation. 

The present chapter discusses aspects, known by the authors, of (a) biomass as feedstock, (b) the concept of bio-refinery, (c) thermochemical routes from lignocellulosic biomass to fuels, and (d) the contribution of catalytic technology. The main focus will be on the catalytic conversion of fast pyrolysis oil into fuels with regard to problems encountered currently and the challenges for future research and development. 

Gonzalez-Vila,F. J.,Tinoco, P., Almendros, G., and Martin,F. (2001). Pyrolysis-GC-MS analysis of the formation and degradation stages of charred residues from lignocellulosic biomass. I. Agric. Food Chem. 49,1128-1131. 

The following examples of pyrolysis equations are oversimplified, but show the essentials. The simplified formula C3(H 0)2 (MW 72) represents the dahf-composition of the organic part in wood, straw or any other lignocellulosic biomass. 

Antal Jr., M. J., "Biomass Pyrolysis A Review of the Literature, Part I Carbohydrate Pyrolysis (vol. 1, pi75-239, 1982) Part II Lignocellulose Pyrolysis (vol. 2, p 1-96, 1985), In Advances in Solar Energy, Eds. K. W. Boer and J. A. Duffie, American Solar Energy Society, New York. 

Antal M. J. (1985) Biomass pyrolysis A review of the literature, part 2-lignocellulosic pyrolysis, in Advances in Solar Energy (Ed. by Boer K. W. and Duflie J. A) 2, 175-255. Plenum Press, New York... 

Antal, M.J., Jr. "Biomass pyrolysis a review of the literature. Part II-lignocellulose pyrolysis." In Adv. in Solar Energy. Boer, K.W. Duffie, J.W. Eds., American Solar Energy Society Boulder CO, 1986, 2, 175. 

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... 

Bu Q, Lei H, Ren S, Wanga L, Holladay J, Qin Zhang A, Tang J, Ruan R. (2011). Phenol and phenolics from lignocellulosic biomass by catalytic microwave pyrolysis. Bioresour Technol, 102, 7004-7007. 

Crude bio-oil (BO) obtained by flash pyrolysis of lignocellulosic biomass contains large proportions of aldehydic compounds. These were successfully hydrogenated to the corresponding alcohols in a water-dichloromethane biphasic system with a catalyst prepared in situ from RuCl3-3H20 and TPPTS at 45-70°C and 0.6 MPa H2 (93). 

Table 8.3 Major chemicals from the pyrolysis of lignocellulosic biomass ...

Pyrolysis of lignocellulosic biomass leads to an array of useful products including liquid and solid derivatives and fuel gases. At the beginning of the twentieth century, pyrolysis processes were utilized for the commercial production of a wide range of fuels, solvents, chemicals, and other products from biomass feedstocks. At the time, the dry distillation of wood for the production of charcoal was the mainstay of the chemical industry. 

As can be seen from Figure 8.6, fast pyrolysis is the primary technology to convert lignocellulosic biomass into biooil, char, and gas. The biooil is feedstock for a subsequent biorefinery approach that aims to further process the biooil into a spectrum of value-added products. This elegant concept is further schematically presented in Figure 8.7. 

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