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Wangda Qu

Document Type

Thesis - University Access Only

Award Date


Degree Name

Master of Science (MS)


Agricultural and Biosystems Engineering

First Advisor

Lin Wei


The thermo-chemical conversion of biomass to hydrocarbons has been investigated for decades as an alternative to using petroleum-derived fuels. Equipment and feedstock have improved, but, biomass conversion efficiency and bio-oil quality still remain challenges. This study aims to investigate the conversion paths of biomass to raw bio-oil and raw bio-oil to upgraded fungible biofuels. The goal is to design and evaluate the new paths and reactors on biomass conversion and bio-oil upgrading. A proprietary fast pyrolysis reactor was used to carry out the study of thermo-chemical conversion of lignocellulosic biomass to raw bio-oil. This reactor converted biomass to bio-oil at a rate of 1 to 2 kilograms per hour. Corn stover and pine sawdust were the feedstocks used for this study. The bio-oil produced was also characterized. Bio-oil produced from pine sawdust had better qualities than that produced from corn stover in moisture content (47.04 wt % versus 54.88 wt %), energy content (13.81 MJ/kg versus 10.19 MJ/kg), and viscosity (9.8 cP versus 3.2 cP). Upgrading the aqueous fraction of raw bio-oil (light bio-oil) was performed using a high pressure fixed-bed reactor (HPF). Catalysts and process conditions were varied and compared. The upgraded light bio-oil had a carbon content of ~ 80 wt %, and an oxygen content of ~ 9 wt %. Heavy bio-oil fraction (viscosity greater than 5000 cP) was upgraded using an autoclave. Catalyst Ru/AC and HZSM-5 were used as catalyst. Process condition named H250+C400 (Hydrotreating at 250°C for 4 hours than instantly cracking at 400°C for 1~2 minutes) was observed the most effective for the heavy bio-oil upgrading. Viscosity of the upgraded heavy bio-oil was reduced from 8710 cP to 70 cP, and the oxygen content decreased from 33.90 wt % to 9.48 wt %. Upgraded heavy bio-oil’s properties were improved significantly and can be easily further refined to fungible drop-in fuels.

Library of Congress Subject Headings

Lignocellulose -- Biotechnology
Biomass conversion
Biomass energy
Liquid fuels


Includes bibliographical references (pages 74-87)



Number of Pages



South Dakota State University


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