Degree Type

Dissertation

Date of Award

2008

Degree Name

Doctor of Philosophy

Department

Mechanical Engineering

First Advisor

Robert C. Brown

Second Advisor

Steven J. Hoff

Third Advisor

Song-Charng Kong

Abstract

Gasification is one means of transforming biomass so that it can be more easily utilized as a renewable source of thermal energy, transportation fuel, and chemicals. Under typical gasification conditions it is not uncommon that a portion of the carbon entering with the biomass leaves the reactor unconverted as char. Understanding and improving carbon conversion during biomass gasification in an atmospheric bubbling fluidized bed reactor is the focus of this study.;To better understand the intricacies of biomass gasification a carbon conversion analytic methodology was developed. The methodology is based on a mass balance of the fixed carbon entering and leaving the gasifier. It allows fixed carbon leaving the reactor by elutriation to be distinguished from that which has been chemically converted. Carbon conversion analysis was applied to several steady state gasification experiments in a laboratory scale bubbling fluidized bed reactor utilizing ground seed corn as the feedstock. The impact on the gasification of ground seed corn was investigated for variations in the equivalence ratio, the gasification temperature, the superficial gas velocity, the biomass particle size, and the concentration of H2O entering the reactor. Insights gleaned from these experiments suggest that carbon conversion during gasification of ground seed corn in a bubbling fluidized bed is limited by elutriation of char comminuted by either fragmentation or chemically assisted attrition. Consequently, increased carbon conversion was realized with reductions in the superficial gas velocity through the reactor.

DOI

https://doi.org/10.31274/rtd-180813-17025

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Kevin Jay Timmer

Language

en

Proquest ID

AAI3316178

OCLC Number

270720131

ISBN

9780549688082

File Format

application/pdf

File Size

171 pages

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