Document Type

Thesis - University Access Only

Award Date

2012

Degree Name

Master of Science (MS)

Department / School

Mechanical Engineering

First Advisor

Michael P. Twedt

Abstract

This research paper was designed to study the cost-effectiveness of various ethanol conversion processes. This paper provides a general overview of advanced ethanol conversion processes and an analysis of the conversion economics for such systems. The analysis was unique in that it focused on the economics of the ethanol facilities versus the process of producing the ethanol. The research attempted to focus on the main factors that could affect the ethanol production cost for various ethanol facilities. The largest contributing factors were then calculated as a dollar per gallon of ethanol to use a price that could be easily compared to the market value of ethanol. Using the factors described in the rest of the paper, mainly facility capital cost, feedstock cost, and conversion efficiency, an economic model was created that helped determine the individual effects impact on the different ethanol facilities. The goal of this analysis was to model different types of ethanol production processes in order to determine and compare their economic costs and values. The conversion processes evaluated in this study were Dry Mill Com Ethanol, Biochemical (Cellulosic) Ethanol using Chemical Extraction, Biochemical (Cellulosic) Ethanol using Mechanical Extrusion, Thermo-Chemical Ethanol using Fischer-Tropsch Synthesis, and Thermo-Chemical Ethanol using Fermentation Based Conversion. The Biochemical and Thermo-Chemical ethanol processes were the two advanced conversion processes; while the Dry Mill Com Ethanol was considered the baseline conversion process or control to judge feasibility. For the advanced biofuels, a dedicated non-food based feedstock was chosen to be used in the facility. The feedstock used in the advanced conversion process for this analysis was Prairie Cord Grass (Spartina pectinata). Prairie Cord Grass is similar to other biomass feedstocks in its basic chemical composition, is available in the upper-Midwest, is a hardy plant, and grows well in the lowland areas that aren't generally favorable farming condition for food based products. The ethanol facilities were sized in the modeling to produce 50 million gallons of ethanol per year using their respective feedstock. The average costs used in the analysis are shown below, but the full analysis is shown in the complete paper. The following production values do not include facility capital costs. The Dry Mill Com Ethanol production facility was modeled to produce ethanol at a cost of $1.65 per gallon of ethanol produced. The Biochemical Ethanol using Chemical Extraction production facility was modeled to produce ethanol at a cost of $2.32 ($0. 78 more than the Dry Mill Com Ethanol production facility) per gallon of ethanol produced. The Biochemical Ethanol with Mechanical Extrusion production facility was modeled to produce ethanol at cost of $2.19 ($0.54 more than the Dry Mill Com Ethanol production facility) per gallon of ethanol produced. The Thermo-Chemical Ethanol using Fischer-Tropsch Synthesis production facility was modeled to produce ethanol at a cost of $1.61 ($0.04 less than the Dry Mill Com Ethanol production facility) per gallon of ethanol produced. The Thermo-Chemical Ethanol using a Fermentation Based Conversion production facility was modeled to produce ethanol at a cost of $1 .55 ($0.10 less than the Dry Mill Com Ethanol production facility) per gallon of ethanol produced. From these results, the thermal chemical facility was able to produce ethanol cheaper than the dry mill facility without accounting for the cost of the facility while the biochemical facilities were still more expensive than the dry mill com ethanol facility. In order to account for the differences in capital, each facility was built brand new on an empty section of land and had a 10 year 7% interest loan that needed to be paid back. The Dry Mill Com Ethanol production facility was determined to cost $100 million in capital; the Biochemical Ethanol using Chemical Extraction production facility was determined to cost $300 million in capital; the Biochemical Ethanol with Mechanical Extrusion production facility was determined to cost $350 million in capital; the ThermoChemical Ethanol with Fischer-Tropsch synthesis production facility was determined to cost $200 million in capital; and the Thermo-Chemical Ethanol using Fermentation Based Conversion production facility was determined to cost $175 million in capital. For the Dry Mill Com Ethanol production facility, meeting the Return on Investment criteria produces the final break even cost of ethanol to be $1.93 per gallon of ethanol produced. The Biochemical Ethanol using Chemical Extraction production facility yields $3 .17 ($1.24 more than the Dry Mill Com Ethanol production facility) per gallon of ethanol produced. The Biochemical Ethanol using Mechanical Extrusion production facility yields $3 .19 ($1.26 more than the Dry Mill Com Ethanol production facility) per gallon of ethanol produced. The Thermo-Chemical Ethanol from Fischer Tropsch synthesis production facility yields $2.17 ($0.24 more than the Dry Mill Com Ethanol production facility) per gallon of ethanol produced. The Thermo-Chemical Ethanol from Fermentation production facility yields $2.05 ($0.12 more than the Dry Mill Com Ethanol production facility) per gallon of ethanol produced. While the thermochemical ethanol conversion was determined to be cheaper to produce, the higher cost of the production facility drove the total cost of the ethanol higher than that of the dry mill com ethanol. In conclusion, it was found that Thermo-Chemical facility was competitive with the Dry Mill Com ethanol facility without regard to the facility cost. However, the Dry Mill Com Ethanol production facility was modeled using the current, historically high price of com at $3.92 per bushel com ($140 per ton com) compared to the $100 per ton prairie cord grass for the other conversion production facilities. This historically high priced com allows Thermo Chemical Ethanol production facilities to compete with Dry Mill Com Ethanol production facility. Finally, the Thermo Chemical Ethanol production facility produces a lower cost fuel in comparison to the Biochemical Ethanol production facility, both with and without facility costs included.

Library of Congress Subject Headings

Ethanol as fuel -- Economic aspects
Ethanol as fuel -- Technological innovations -- Economic aspects
Ethanol fuel industry

Publisher

South Dakota State University

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Rights Statement

In Copyright