Date of Award

12-2014

Level of Access

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Chemical Engineering

Advisor

Clayton Wheeler

Second Committee Member

William J. DeSisto

Third Committee Member

Douglas W. Bousfield

Abstract

The purpose of this study is to determine the capital and operating cost for producing liquid fuel from biomass by using Formate-Assisted Pyrolysis (FAsP) process. Many studies have been published about producing liquid fuel from biomass by using fast pyrolysis. Fast pyrolysis produces bio-oil with 60% mass yield; however, the bio-oil is unstable, has a high amount of oxygen (35 wt%) and requires high capital cost to upgrade it. Formate-Assisted Pyrolysis (FAsP), a new method being developed at the University of Maine, produces a bio-oil that is more stable and has less amount oxygen. FAsP uses the same operating conditions as fast pyrolysis (500 °C and atmospheric pressure), but also integrates the thermal decomposition of formate salts. Typical FAsP oil has (15 wt%) oxygen and 40% energy yield. Experiments were done by another student using different calcium formate/biomass ratios.

An Aspen Plus® process model has been developed for a 2000 dry metric ton of biomass per day FAsP plant. The model includes feedstock sizing and drying, pyrolysis, hydrogen production and hydrotreatment of FAsP oils, and recycle of calcium. The char is used to provide heat for the kiln reactor. Other gases from upgrading and pyrolysis are used to produce hydrogen which is necessary for bio-oil upgrading. The bio-oil is upgraded to reach a final 18% gasoline/diesel mass yield and 42% energy yield based on the dry biomass fed.

The total capital investment for a grass-roots plant was estimated to be US$276 million with an annual cost of manufacturing of US$171 million. With a 20 year project life, a minimum selling price for hydrocarbon fuel was determined to be US$3.91 per gallon with a 15% return on investment.

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