The conversion of lignocellulosic biomass to fuels and chemicals is an active area of research at the National Renewable Energy Laboratory (NREL). Thermochemical and enzymatic processes are used to convert cellulose and hemicellulose to their component sugars for subsequent fermentation to useful products. NREL currently employ a high-temperature, dilute sulfuric acid pretreatment to hydrolyze hemicellulose followed by enzymatic hydrolysis of the cellulose. NREL is seeking to reduce both operating and capital cost by increasing the concentration of solids processed during enzymatic hydrolysis and fermentation processes. However, operating at high solid concentrations is challenging due to limited understanding of the rheological and mixing characteristics of high-solid biomass slurries and subsequent problems with heat and mass transfer. In addition, dynamic changes in rheology and mixing requirements can occur as the cellulose structure is broken down during enzymatic hydrolysis. The objective of this effort is to develop a fundamental understanding of the rheology and mixing of high-solids biomass slurries, ultimately generating information useful for process design. Interested parties can address ONE OR BOTH of the following topics: 1. Characterization and Modeling the Rheology of High-Solids Biomass Slurries. This study should identify and quantify the factors that influence rheology of high-solids biomass slurries during enzymatic hydrolysis leading to development of mathematical models. The models should describe slurry rheology in terms of measurable parameters and slurry/biomass characteristics as they undergo transformation during enzymatic hydrolysis. Some of the factors that we believe are likely to influence rheology are listed below. · Physical parameters – concentration of solids and particle size. · Chemical structure– type of plant material and structure modification during chemical pretreatment and during enzymatic hydrolysis · Interaction between biomass particles – electrostatic, friction, entanglement · Characteristics of external fluid – pH, ionic strength, viscosity While the above list is not exhaustive, it indicates the complexity involved in describing the rheology of high-solids biomass slurries. 2. Reactor Design and Mixing of High-Solids Biomass Slurries. This study should develop reactor(s) designs to achieve good enzyme distribution and uniform temperature control with low mixing power input during high-solids enzymatic hydrolysis. This task would likely involve the following components: · Design, purchase and/or construction of bench- and pilot-scale reactors · Performance testing · Development of fluid dynamic models to assist in scale-up Pretreated corn stover will be the material for these studies, although, pretreated poplar might be included as another test biomass source at a later stage during the project(s). Chemically pretreated biomass will be supplied by NREL as part of this effort. Interested parties should have a proven ability (i.e., facility and equipment) to perform this work, previous experience with the subject matter, and the ability to develop a strong experimental plan addressing project goals. The responses to this SOURCES SOUGHT DOCUMENT is limited to 8 pages of single spaced text of 12-point font or equivalent, with a minimum of 1 inch margins all around. Brevity is encouraged. Any organizations interested in working with NREL to provide the above described effort may mail a list of qualifications, based on the either both topics or one of the two topics, including subpoints, discussed above. Qualifications should be mailed to the following: Deborah J. Bullard, National Renewable Energy Laboratory, MS 3511, 1617 Cole Blvd., Golden, CO 80401-3393. Submittals by e-mail are acceptable and should be sent to the following: [email protected]. Electronic format of the Sources Sought response shall be in MSWord/Excel or WordPerfect. DO NOT SEND SCANNED .PDF files. TELEPHONE CALLS WILL NOT BE ACCEPTED. Qualifications will be responsive to the items listed above. Responses to this notice, whether mailed hard copy or sent electronically, must be received by 3:00 MST, Novemer 22, 2004. Responding to this request identifies your organization as an interested candidate only. Your submittal is NOT in response to a Request for Proposals (RFP).

Bid Protests Not Available