(165c) Partial Oxidative Pyrolysis of Biomass

Xianglan Bai ^{1, 4}, Kwang Ho Kim^{2, 4}, Marge Rover ⁴ and Robert C. Brown ^3,4

1. Department of Aerospace Engineering

2. Department of Agricultural and Biosystem Engineering

3. Department of Mechanical Engineering

4. Center for Sustainable Environmental Technologies

Iowa State University Ames, Iowa 50010

Fundamental studies of biomass pyrolysis are conducted in micro-scale pyrolysis/GC systems.  In such systems, biomass is usually pyrolyzed in an inert atmosphere because of the operational constraints on the GC. In contrast, industrial-scale pyrolysis reactor systems, operating with a continuous flow of biomass into the reactor, convey air within the void space surrounding biomass particles with the result that a significant amount of oxygen can be present during pyrolysis. Considering the strong reactivity of oxygen, thermal depolymerization in industrial-scale pyrolysis reactor systems could be quite different from the reactions in micropyrolyzers. The influence of oxygen on thermal depolymerization of biomass must be addressed in order to improve our understanding for better control of pyrolysis in industrial-scale pyrolyzers.

In the present study, red oak feedstock was pyrolyzed in a lab-scale fluidized bed using nitrogen gas mixed with oxygen at concentrations range from 0 % to 4.2 % as sweep gas.  The effects of oxygen on the yields of pyrolysis products including bio-oil, char and noncondensable gases were investigated. The chemical compositions and physio-chemical properties of bio-oil obtained from oxidative pyrolysis and pure pyrolysis were compared quantitatively to examine the effects of oxygen concentration on pyrolysis products. The properties of the char obtained at different test conditions were also studied.