Robert Wooley

Lignocellulosic Biomass to Ethanol Process Design and Economics Utilizing Co-Current Dilute Acid Prehydrolysis and Enzymatic Hydrolysis Current and Futuristic Scenarios

The National Renewable Energy Laboratory (NREL) has undertaken a complete review and update of the process design and economic model for the biomass-to-ethanol enzymatic based process. The process design includes the core technologies being researched by the U.S. Department of Energy (DOE): prehydrolysis, simultaneous saccharification and co-fermentation, and cellulase enzyme production. In addition, all ancillary areas--feed handling, product recovery and purification, wastewater treatment lignin burner and boiler--turbogenerator, and utilities--are included. NREL engaged Delta-T Corporation to assist in the process design evaluation, equipment costing, and overall plant integration. The process design and costing for the lignin burner and boiler turbogenerator has been reviewed by Reaction Engineering Inc. and the wastewater treatment by Merrick and Company. An overview of both reviews is included here. The purpose of this update was to ensure that the process design and equipment costs were reasonable and consistent with good engineering practice for plants of this type using available technical data. This work has resulted in an economic model that can be used to predict the cost of producing ethanol from cellulosic biomass using this technology if a plant were to be built in the next few years. The model was also extended using technology improvements that are expected to be developed based on the current DOE research plan. Future process designs and cost estimates are given for the years 2005, 2010, and 2015.

Determining the Cost of Producing Ethanol from Corn Starch and Lignocellulosic Feedstocks

The mature corn-to-ethanol industry has many similarities to the emerging lignocellulose-to-ethanol industry. It is certainly possible that some of the early practitioners of this new technology will be the current corn ethanol producers. In order to begin to explore synergies between the two industries, a joint project between two agencies responsible for aiding these technologies in the Federal government was established. This joint project of the USDA-ARS and DOE/NREL looked at the two processes on a similar process design and engineering basis, and will eventually explore ways to combine them. This report describes the comparison of the processes, each producing 25 million annual gallons of fuel ethanol. This paper attempts to compare the two processes as mature technologies, which requires assuming that the technology improvements needed to make the lignocellulosic process commercializable are achieved, and enough plants have been built to make the design well-understood. Ass umptions about yield and design improvements possible from continued research were made for the emerging lignocellulose process. In order to compare the lignocellulose-to-ethanol process costs with the commercial corn-to-ethanol costs, it was assumed that the lignocellulose plant was an Nth generation plant, built after the industry had been sufficiently established to eliminate first-of-a-kind costs. This places the lignocellulose plant costs on a similar level with the current, established corn ethanol industry, whose costs are well known. The resulting costs of producing 25 million annual gallons of fuel ethanol from each process were determined. The figure below shows the production cost breakdown for each process. The largest cost contributor in the corn starch process is the feedstock; for the lignocellulosic process it is the capital cost, which is represented by depreciation cost on an annual basis.

Process Design and Costing of Bioethanol Technology: A Tool for Determining the Status and Direction of Research and Development

Bioethanol is a fuel‐grade ethanol made from trees, grasses, and waste materials. It represents a sustainable substitute for gasoline in todays passenger cars. Modeling and design of processes for making bioethanol are critical tools used in the U.S. Department of Energys bioethanol research and development program. We use such analysis to guide new directions for research and to help us understand the level at which and the time when bioethanol will achieve commercial success. This paper provides an update on our latest estimates for current and projected costs of bioethanol. These estimates are the result of very sophisticated modeling and costing efforts undertaken in the program over the past few years. Bioethanol could cost anywhere from

The effect of overliming on the toxicity of dilute acid pretreated lignocellulosics: the role of inorganics, uronic acids and ether-soluble organics.

1.16 to

Softwood forest thinnings as a biomass source for ethanol production: a feasibility study for California.

1.44 per gallon, depending on the technology and the availability of low cost feedstocks for conversion to ethanol. While this cost range opens the door to fuel blending opportunities, in which ethanol can be used, for example, to improve the octane rating of gasoline, it is not currently competitive with gasoline as a bulk fuel. Research strategies and goals described in this paper have been translated into cost savings for ethanol. Our analysis of these goals shows that the cost of ethanol could drop by 40 cents per gallon over the next ten years by taking advantage of exciting new tools in biotechnology that will improve yield and performance in the conversion process.

Implementing Systems Engineering in the U. S. Department of Energy Office of the Biomass Program

Although the treatment of dilute acid pretreated lignocellulosics with calcium hydroxide or carbonate (overliming) is known to improve the fermentability of carbohydrate-rich hydrolyzate streams, a firm understanding of the chemistry behind the process is lacking. Quantitative evaluation of inorganics, uronic acids, and non-polar organics indicates that only a portion of the improvement can be ascribed to these materials. Upon overliming the concentrations of inorganics either increase (Ca, Mg), decrease (Fe, P, Zn, K) or remain relatively the same (Al, Na). Furthermore, organic compounds that are not extractable with tert-butyl methyl ether (MTBE) are toxic to Zymomonas mobilis CP4(pZB5). Overliming and direct neutralization are somewhat effective in removing sulfate anions, although sulfate toxicity is considerably less than that of acetic acid. Uronic acids were found to be non-toxic under pH controlled conditions.

Process Design Report for Wood Feedstock: Lignocellulosic Biomass to Ethanol Process Desing and Economics Utilizing Co-Current Dilute Acid Prehydrolysis and Enzymatic Hydrolysis Current and Futuristic Scenarios

A plan has been put forth to strategically thin northern California forests to reduce fire danger and improve forest health. The resulting biomass residue, instead of being open burned, can be converted into ethanol that can be used as a fuel oxygenate or an octane enhancer. Economic potential for a biomass‐to‐ethanol facility using this softwood biomass was evaluated for two cases: stand‐alone and co‐located. The co‐located case refers to a specific site with an existing biomass power facility near Martell, California. A two‐stage dilute acid hydrolysis process is used for the production of ethanol from softwoods, and the residual lignin is used to generate steam and electricity. For a plant processing 800 dry tonnes per day of feedstock, the co‐located case is an economically attractive concept. Total estimated capital investment is approximately

A Nine-Zone Simulating Moving Bed for the Recovery of Glucose and Xylose from Biomass Hydrolyzate

70 million for the co‐located plant, and the resulting internal rate of return (IRR) is about 24% using 25% equity financing. A sensitivity analysis showed that ethanol selling price and fixed capital investment have a substantial effect on the IRR. It can be concluded that such a biomass‐to‐ethanol plant seems to be an appealing proposition for California, if ethanol replaces methyl tert‐butyl ether, which is slated for a phaseout.

ORIGINAL RESEARCH: The eco-profiles for current and near-future NatureWorks® polylactide (PLA) production

The DOE Biomass Program is tackling the challenge of advancing biomass energy technologies and systems from concept to commercial adoption with a goal of enabling the production and use of biofuels to help reduce future U.S. oil consumption. The complexity of the biomass-to-biofuels system of systems and the combined dynamics of the existing agriculture, forestry, energy and transportation markets within which it operates pose challenges for reaching consensus on both a concept of operations and preferred strategies for transitioning to a significantly larger biofuels industry that is secure, reliable, environmentally responsible, and supportive of a thriving economy. To ensure that the program is focused on the activities critical to achieving its goal, the program is implementing systems engineering processes, practices, and tools to guide informed decision-making.

Standing-wave design of tandem SMB for linear multicomponent systems

The National Renewable Energy Laboratory (NREL) has undertaken a complete review and update of the process design and economic model for the biomass-to-ethanol process based on co-current dilute acid prehydrolysis, along with simultaneous saccharification (enzymatic) and co-fermentation. The process design includes the core technologies being researched by the U.S. Department of Energy (DOE): prehydrolysis, simultaneous saccharification and co-fermentation, and cellulase enzyme production.