Degree Type


Date of Award


Degree Name

Master of Science


Mechanical Engineering

First Advisor

Robert C. Brown


This study compares capital and production costs of two biomass-to-liquid production plants based on gasification. The goal is to produce liquid transportation fuels via Fischer-Tropsch synthesis with electricity as co-product. The biorefineries are fed by 2000 metric tons per day of corn stover. The first biorefinery scenario is an oxygen-fed, low temperature (870yC), non-slagging, fluidized bed gasifier and the second scenario an oxygen-fed, high temperature (1300yC), slagging, entrained flow gasifier. Both are followed by catalytic Fischer-Tropsch synthesis and hydroprocessing to naphtha and distillate liquid fractions.

Process modeling software is utilized to organize the mass and energy streams and cost estimation software is used to generate equipment costs. Economic analysis is performed to estimate the capital investment and operating costs. A 20 year discounted cash flow rate of return (DCFROR) analysis is developed to estimate a fuel product value (PV) at a net present value of zero with 10% internal rate of return. All costs are adjusted to the year 2007.

Results show that the total capital investment required for nth plant scenarios are $610 million and $500 million, for high temperature and low temperature scenarios, respectively. PV for the high temperature and low temperature scenarios are estimated to be $4.30 and $4.80 per gallon of gasoline equivalent (GGE), respectively. The main reason for a difference in PV between the scenarios is because of a higher carbon efficiency and subsequent higher fuel yield for the high temperature scenario. Sensitivity analysis is also performed on process and economic parameters which shows that total capital investment and feedstock cost are among the most influential parameters affecting the PV while least influential parameters include per pass Fischer-Tropsch reaction conversion extent, inlet feedstock moisture, and catalyst cost.

In order to estimate the cost of a pioneer plant (1st of its kind) an analysis is performed which inflates total capital investment and deflates the plant output for the first several years of operation. Base case results of this analysis estimate a pioneer plant investment to be $1.3 billion and $1.0 billion for high temperature and low temperature scenarios, respectively. Resulting respective PV are estimated to be $7.40 and $7.70 per GGE for pioneer plant.

Copyright Owner

Ryan Michael Swanson



Date Available


File Format


File Size

172 pages