(373e) Fischer-Tropsch Synthesis in Microstructured Reactors: from Laboratory to Commercial Systems

The GTL process is the result of concerted technical effort at the turn of the last century to produce motor fuels from Germany's plentiful coal supplies. Franz Fischer and Hans Tropsch developed processes in the 1920's to convert CO and hydrogen to higher hydrocarbons using iron and cobalt catalysts. The technology was successfully commercialized during the 1930's and 1940's. Interest in the FT process waned in the post-war years, but was later adopted by Sasol of South Africa. In recent years, interest in the FT process has intensified in response to a global increase in oil prices and potential shocks to production. At present several commercial FT processes are used: a tubular fixed bed, slurry bed, fluid bed, and circulating fluid bed. All processes are operated with a Gas Hourly Space Velocity (GHSV) less than 1000 hr-1 with a selectivity to the undesired methane side product near 10%. Methane production is a strong function of temperature, as the catalyst temperature increases with the exothermic reaction, the methane selectivity continues to rise. The use of microstructured reactors for GTL has demonstrated improved temperature control and reduced methane selectivity for GHSV's greater than 10,000 hr-1, but in small capacity reactors. The scaleup challenge of enhanced FT performance in large scale microstructured reactors has not yet been addressed in the literature. This work will describe the key steps to scaleup of the technology, including flow distribution, manuafacturing, and catalyst integration and stability. Technologies have been developed to minimize flow maldistribution across multichannel devices with hundreds to thousands of parallel channels. Similarly, manufacturing methods have been developed for the multichannel devices. Catalyst performance at the large scale has matched that at the small scale. These topics are woven to explore the commercial development of the technology.