Degree Type

Dissertation

Date of Award

2013

Degree Name

Doctor of Philosophy

Department

Agricultural and Biosystems Engineering

First Advisor

Matthew J. Darr

Abstract

Corn stover is the primary feedstock choice for most of the first-generation cellulosic biorefineries in the Midwest, and their rated capacities are in between 76 and 114 million liters per year (MLPY) (i.e., 20 and 30 million gallons per year (MGPY)). For the uninterrupted operation of these plants, a year-round supply of corn stover needs to be secured, which will require a robust, efficient, cost-effective and environmentally-balanced feedstock supply chain. However, there is limited techno-economic and environmental know-how in this area. Thus, the main objective of this dissertation is to stochastically analyze the technoeconomics, life-cycle energy use, and greenhouse gas emissions (GHGE) of the corn stover biomass feedstock supply chain having high likelihood of industrial implementation by the first-generation Midwest-based 114 MLPY (30 MGPY) cellulosic biorefineries using production-scale field data collected in Iowa. Different components of this supply chain include corn stover harvesting, collection and stacking at the field-edge, handling and transportation of bales from the field-edge to the distributed centralized facilities for storage, and then to the biorefinery plant, and finally the audit of nutrients removed with stover from the field. A Midwest-based 114 MLPY cellulosic biorefinery, on an average, requires around 374 thousand std. Mg (413 thousand std. ton) of corn stover feedstock each year, and the execution of different supply chain activities to deliver this quantity of stover to the plant, on an average, requires around 250 thousand hours equivalent of labor and 4.3 million L (1.2 million gal) of diesel fuel. Average cost, energy use, and GHGE for biorefinery gate delivered stover are estimated to be 121.9 $-std. Mg-1 (110.6 $-std. ton-1), 1502 MJ std. Mg-1 (1.3 million BTU std. ton-1), and 95.2 kg CO2e std. Mg-1 (190.4 lb CO2e std. ton-1), respectively. Furthermore, bale density and length, harvest rate, baler field efficiency and fuel consumption, dry matter loss, nitrogen removed with stover harvest, and harvest window are the top five parameters influencing the overall cost, energy use, and GHGE of the supply chain. In addition to these results, this dissertation discusses some potential strategies to reduce the supply chain costs, energy use, and GHGE.

DOI

https://doi.org/10.31274/etd-180810-3563

Copyright Owner

Ajay Shah

Language

en

File Format

application/pdf

File Size

237 pages

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