Economics of Pretreatment for Biological Processing

Economics of Pretreatment for Biological Processing

Ling Tao¹, Andy Aden¹ and Richard T. Elander¹

¹ National Renewable Energy Laboratory, 1617 Cole Blvd., Golden, CO 80401, USA

Abstract:

A broad understanding of pretreatment economics within an overall conversion context will be presented.  The importance of pretreatment in the overall economics of the biorefinery is addressed along with the key parameters that influence the pretreatment economics.  A large array of pretreatment technology options exist and are currently being researched and developed in this study. There appear to be many performances and cost tradeoffs for these varying technologies.  Only through continued R&D will these tradeoffs be more fully understood. Process economics, especially the promising pretreatment technologies studied in the Consortium for Applied Fundamentals and Innovation (CAFI) projects, are analyzed and compared in details in this work. The six pretreatment technologies vary greatly in terms of their process design and projected total capital investment. Pretreatment area capital costs are based on past research, existing databases and engineering judgments, and include not only pretreatment reactor costs, but also pretreatment chemical recovery and recycle equipment costs for the processes that use high pretreatment chemical loadings. More accurate cost estimates for each pretreatment process will require specific vendor quotations based on pretreatment process conditions and any pretreatment chemical recovery requirements. Overall ethanol yield, which is largely based on achieved overall sugar yield achieved in pretreatment and subsequent enzymatic hydrolysis steps, is one of the single-most important factors in determining projected ethanol costs for each process. Many key variables and parameters can have significant impact on the pretreatment economics.  While many are discussed within this talk, continuing R&D will generate data that further guide the development of the biomass conversion industry.