Lignocellulosic thermal pyrolysis

Simple thermal pyrolysis of lignocellulosics with or without additives has been reviewed by several authors (15-17). In contrast to microwave pyrolysis, reasonably extensive conventional pyrolysis product characterization has been conducted for certain types of biomass (15-25) and some of these results will be compared to those cited here. To these authors knowledge, no single study on microwave pyrolysis (plasma or di-electric loss mode) has identified the components of all product fractions nor their relative amounts work reported here has been extended by others (43,44) to include pyrolysis studies of biomass fractions and other types of biomass with the emphasis on detailed product characterization, formation kinetics, and effect of transport rates. 

Up to about 70 C, plant tissues are thermally stable, as they must be in nature to avoid damage from prolonged direct exposure to the sun. Pyrolysis, the chemical decomposition by heat, starts in dry lignocellulosics around 100 C, in moist ones below 80 C. It accelerates as temperature rises, peaking in many organic materials between 275 and 300 C, at which point cellulose disintegrates. 

These adsorptions appear to be inconsistent with the evolution of carbon dioxide and other volatiles out of the charring solid in the pyrolysis process. The adsorptive properties develop as pyrolysis frees sites for adsorption debris escaping from thermally decomposing lignocellulosics leaves the char residue with a highly reactive, eagerly adsorbing inner surface. 

Various chemistries and processes can be applied to convert lignocellulosic materials into valuable fuels and chemicals [3, 19]. For instance, thermal reactions are exploited in the pyrolysis of biomass to charcoal, oil and/or gases and its gasifica-... 

Pyrolysis kinetics of all the selected lignocellulosic wastes is properly described over the wide thermal degradation range 25°C 900°C by a model that considers an increasing dependence of the activation energy on the temperature and waste conversion with the process course. Appreciable differences in the estimated kinetic parameters are found. 

In diis chapter, the main technical aspects of different thermochemical processes for biomass conversion are discussed. In addition, various hydro-thermal treatments applied to lignocellulosic biomass for the production of fermentable sugars, hydrogen or other value-added products are presented. This chapter also describes about pyrolysis along with its various parameters that influence conversion product yields. Bio-oil, which is a complex mixture or both aqueous and organic biomass components, is discussed in details along with its catalytic upgrading for use as transportation fuel. 

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