PILOT PLANTS. Fischer-Tropsch Oil Circulation Processes

Abstract

A summary of Fischer-Tropsch process development is given including the essential features of the German fixed bed system and the hot gas recycle and oil circulation processes; the oil slurry and fluidized bed systems are briefly described. Most of the pilot plant experimentation at the Bureau of Mines has been directed toward the development of the oil circulation process because a simple converter design could be used and precise operating control attained in such a system. Several moderately successful experiments, which employed a cooling oil circulating through a fixed catalyst bed, were operated. However, shutdowns were necessitated after 3 or 4 months of synthesis because the catalyst particles became cemented together, and an excessive pressure drop developed across the catalyst bed. This problem of catalyst cementing was circumvented by employing a moving bed of catalyst in which lifting action of the circulating oil was used to expand the catalyst bed and keep the particles in motion. Details of induction and synthesis operations, operating data, analyses of gas and liquid streams, calculated yields, and a typical product distribution are given for various experiments. Calculated yields of gasoline and diesel products resulting from thermal and catalytic cracking of heavy distillate and waxmore » are given along with characterization of the gasoline and diesel oil.« less