Economic Feasibility of Corn Stover Torrefaction for Distributed Processing Systems

This study investigated the economic feasibility of distributed or decentralized torrefaction bio-refining using corn stover feedstock to generate value added products. Distributed bio-refining systems would be able to operate on private farm and commercial scales, eliminating the need for large capital investment for large processing facilities and decreasing logistical concerns for harvesting and marketing corn stover. A techno-economic model was developed to analyze the economics of harvesting techniques, logistics, processing requirements, and end product utilization. With the model, a base case analysis was established to analyze average values and to create a basis in which to compare a variety of economic scenarios. A sensitivity analysis was also completed to investigate outcomes based on variability of crop yields and product price, as well as costs associated with harvesting stover, input for operating the torrefaction system, and capital costs of equipment. Results of the analyses were quantified with respect to input costs required to generate torrefied products, potential profit of processed products, and the payback period of the production and conversion system. Preliminary results indicated that processing corn stover feedstock within a distribution torrefaction bio-refining system had high potential, in terms of economic feasibility, over a wide range of scenarios. Results indicated that payback periods as low as five years were possible under a wide variety of applications and operating costs. In addition to operating economically, it was also shown that end products could have increasing profit potential as a value added product.