Thesis
Torrefaction of Douglas fir pellets and bio-oil upgrading
Washington State University
Master of Science (MS), Washington State University
2015
Handle:
https://hdl.handle.net/2376/102987
Abstract
The main objective of this thesis is to investigate the effects of reaction conditions on torrefaction product distribution. The effects of reaction conditions of Parr reactor torrefaction on the yields of products were first determined. The reaction temperature and time significantly influenced the yields of biochar, bio-oil, and non-condensable gases. Three linear models were developed to predict the product yields as a function of reaction temperature and time. Gas Chromatography Mass Spectrometry (GC/MS) analysis of bio-oil showed that the bio-oils were mainly composed of furans, phenolics, sugars, ketones/aldehydes, and organic acids. The amounts of each compound varied with the reaction conditions. Higher heating values (HHV) of torrefied biomass ranged from 19.45-27.02 MJ/kg, approximately 5-46% increase compared to the HHV of raw biomass. The energy yields of biochar from 57.07-68.56% implied that energy was partially retained in the torrefied biomass. One linear model as a function of reaction temperature and time was developed to predict the energy yield. Another objective is to assess the feasibility of conducting lab-scale torrefaction using Parr reactor through comparison with microwave torrefaction. Comparison of Parr reactor and microwave torrefaction was performed. Results shown that biochar yields of Parr reactor torrefaction are 20.58% lower than those of microwave torrefaction on average. And, the energy yields of biochar from Parr reactor torrefaction are 15.39% lower than those of microwave torrefaction on average. As one of the main products of torrefaction, Parr reactor torrefaction derived bio-oil upgrading by ZSM-5 zeolite catalyst was studied. The result shown that the quality of bio-oil has significantly improved by zeolite cracking. Guaiacols and hydrocarbons were the most abundant compounds which is about 48 area%. It was found that hydrocarbon content increased by 885%, from 2.01 area% to 17.80 area%. Also, the acid content was eliminated, which indicates that zeolite cracking overcame one of the major disadvantages of bio-oil.
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Details
- Title
- Torrefaction of Douglas fir pellets and bio-oil upgrading
- Creators
- Yupeng Liu
- Contributors
- Hanwu Lei (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Systems Engineering, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525105801842
- Language
- English
- Resource Type
- Thesis