Date of Award

12-2016

Level of Access

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Chemical Engineering

Advisor

William DeSisto

Second Committee Member

M. Clayton Wheeler

Third Committee Member

Brian Frederick

Abstract

In the context of a petroleum-deprived future, the use of biomass as a source of renewable energy has become imperative to meet increasing energy demands. Fast pyrolysis of lignocellulosic biomass has been researched extensively as a promising process for converting lignocellulosic biomass into energy-dense fuels. Though this technology holds promise for a sustainable energy source, its commercial applications are still hindered due to instability of pyrolysis oil resulting from the high oxygen content of the oil. Research in our group has shown that calcium pretreatment of biomass prior to pyrolysis stabilizes the bio-oil by significantly lowering the oxygen content of the oil. Among the choices of calcium salts studied, calcium formate showed the highest relative yield alongside with deoxygenation activity. Calcium formate decomposes to hydrogen and carbon monoxide during pyrolysis, which is believed to slow the formation of char from secondary pyrolysis reactions resulting in improved bio-oil yields. While atmospheric pyrolysis has proven to be quite inexpensive and robust process, elevated pressure pyrolysis (up to 150 psig), however, can offer some enhancements in chemical reaction kinetics without hugely increasing operating costs. This applies to further reduction of char formation during secondary pyrolysis reactions with calcium formate as well as catalytic pyrolysis reactions that utilize a reducing gas such as hydrogen. The present work seeks to gain an understanding of the effect of pressurized pyrolysis of biomass on the product composition and yield. In this work, pressurized pyrolysis of calcium formate-pretreated biomass at varying pressures is explored. Varying calcium loadings in pretreatment stage was also looked at. The pyrolysis process will be described along with detailed physical and chemical analysis of the pyrolysis products. The analytical results provide some insights into how reactor dynamics directly affects the pyrolysis products and yields.

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