To date, two entities within the State of Mississippi have constructed full-scale facilities that convert waste products into synthesis gas (syngas). The composition of these gases can be controlled during syngas generation, which is a great advantage over the previously performed work on refinery waste gases, in that a customized syngas can potentially be tailored to best match the needs of a high performing ethanol producers within a commercial fermenter. Common compositional percentages reported by one of these facilities are on the order of 45% hydrogen, 25% carbon monoxide, 20% carbon dioxide, and the balance made up primarily of methane and aromatic compounds. One of the two full scale facilities in Mississippi has selected an abiotic catalytic process to produce ethanol (located in Aberdeen, MS). The other facility, located in Winona, MS (one hour west of MSU), has decided to pursue the use of the biotic fermentation process discussed above. This facility will utilize waste sawdust generated from several sawmills within a short radius of the plant to process approximately 65 tons per day. Estimated conversion rates reported from the literature are in the approximately 3,500 - 4,500 gallons per day of ethanol range using the 65 tpd biomass feedrate (i.e. ~55 - 70 gallons per ton).

MSU has entered into a developmental agreement with the Winona Plant (owned by Mississippi Ethanol Inc. [ME]) to assist in the incorporation of a fermentation process into a full-scale facility that will convert the syngas into ethanol. The fermentation process design focuses on the use of the fermentation technique previously developed under DOE funding. This effort will only focus on matching the DOE process to the syngas produced by ME without any additional efforts in terms of development of new organisms, furthering optimization techniques using a wide variety of potential enhancement techniques, and researching of potential new process configurations to optimize ethanol and other product recoveries (i.e. acetic acid). The current collaborative effort between ME and MSU is not being undertaken as a research and development project, but a design oriented venture. The R&D effort being developed under this proposal is a research and development effort that could yield key information and technology that could greatly assist ME in ensuring the commercial viability of their venture, while providing an excellent industrial-scale backdrop for proving the techniques potentially developed under the requested DOE-EPSCoR funding.

Fermentation of acid hydrolyzate is presently being commercially advanced by an Australian consortium comprised of the Manildra Group, the State Forests of New South Wales, Apace Research, and the Australian Greenhouse Office. This effort is being conducted in conjunction with TVA and USM. The project team estimates completion of a research and development pilot plant in 2002 that will convert hardwood sawdust into ethanol. In this pilot plant, hardwood sawdust will be impregnated with concentrated sulfuric acid using twin screw extruders fabricated from Alloy 20 stainless steel. Thereafter, the extruder output stream is diluted with water and then hydrolyzed in a zirconium tube reactor at elevated temperatures. The hydrolyzate from the tube reactor is filtered to remove solids and then routed to a continuous ion exclusion separation system. The dilute acid stream from the separation system is concentrated and then reused in impregnation. The sugars from the separation system are routed to fermentation for conversion to ethanol. It is expected that the Australian pilot plant will have a yield greater than 55 gallons of ethanol per ton of dry hardwood sawdust (Hester et al. 1997).