Date of Award
1993
Degree Type
Dissertation
Degree Name
Doctor of Philosophy
Abstract
The science of biomass fast pyrolysis is relatively young and incomplete. To date, there has been no systematic attempt to define fast pyrolysis in terms of chemistry, product distribution, kinetics, heat transfer requirements, and requisite process conditions. Neither has there been any experimental work which tracks the reaction progress as a function of both temperature and residence time. Furthermore, the literature provides a fragmented and often contradictory view of the nature of fast pyrolysis.;This thesis provides a coherent picture of the fast pyrolysis of cellulose and wood via an extensive literature review and systematic research. The literature review is an essential element of the thesis. It is not an uncritical summary, but is an interpretive integration of published knowledge. As such, it provides a comprehensive structure for the characterization of biomass fast pyrolysis.;The literature review suggests that fast pyrolysis reactions consist of biomass activation followed by primary fragmentation and secondary vapour-phase cracking; the secondary cracking reactions are the focus of the thesis experimental work. This work was carried out predominantly in the Ultrapyrolysis plant at the University of Western Ontario, and to a lesser degree in the RTP plant at Ensyn Technologies Inc.;Both reactor systems provide extremely rapid heat transfer to biomass combined with precise control of short residence times. In order to prove the integrity and reliability of the hardware, initial work involved the rapid pyrolysis of a model compound (ethane) and a comparison of the use of both gaseous and solid particulate heat transfer media. The cornerstone work involved the systematic characterization of the product distribution of secondary cracking reactions as a function of temperature and residence time. The ranges of temperatures and residence times under investigation were 650 to 900{dollar}\sp\circ{dollar}C and 30 ms to 1 s, respectively. The data from this work was used to generate rate equations for the secondary reactions of cellulose and wood fast pyrolysis. Finally, a cooperative study was conducted with the University of Waterloo to compare cellulose fast pyrolysis results from two independent reactor systems. The joint study exhibited excellent agreement and congruity over a broad range of pyrolysis temperatures.
Recommended Citation
Graham, Robert George, "A Characterization Of The Fast Pyrolysis Of Cellulose And Wood Biomass" (1993). Digitized Theses. 2292.
https://ir.lib.uwo.ca/digitizedtheses/2292