Oxygenated octane enhancers: Syngas to isobutylene. Technical progress report No. 18, July 1, 1995--September 30, 1995

The goals of this project are to develop a catalyst and process for the conversion of syngas to isobutanol. The research will identify and optimize key catalyst and process characteristics. In addition, the commercial potential of the new process will be evaluated by an economic analysis. The combination of the best conditions from independent process variable studies has afforded the best performance to date with the 2% Pt on Zn/Mn/Zr oxide catalyst. At 325{degrees}C, 300 psig, 7/1 MeOH/EtOH molar feed ratio and 1 hr{sup {minus}1} MEOH WH 22.20% selectivity to isobutanol is obtained with 55 and 97% conversions of methanol and ethanol, respectively. The results of this run will be used as a basis for the economic evaluation of a higher alcohols process. The ability of the Pt on Zn/Mn/Zr oxide catalyst to produce isobutanol in the presence of high partial pressures of H{sub 2} has been investigated. Such operation could allow the integration of a higher alcohol process with a conventional methanol synthesis plant by placing it within the methanol synthesis recycle loop. However, higher alcohol yields are severely suppressed by a large H{sub 2} cofeed, even at pressures as low as 50 psig. Elimination of the H{sub 2} co-feed did not restore the performance of the catalyst to expected levels, suggesting that the high H{sub 2} partial pressure has caused degradation of the catalyst. No further testing of high H{sub 2} conditions is planned. The commercial system has been modeled using the product slate obtained from the ``best case`` pilot plant conditions combined with the assumption of equilibrium CO, H{sub 2}O, CO{sub 2} and H{sub 2} makes. A stand-alone isobutanol plant processing 500 MT/D synthesis gas-derived methanol can yield 92 MT/D isobutanol and additional 20 MT/D assuming complete hydrogenation of isobutyraldehyde which accumulates in the liquid recycle loop. The economic analyses of this system are pending