Published: December 2011
Fischer-Tropsch synthesis generally involves the synthesis of alkane waxes (of varying chain lengths) and oxygenates from synthesis gas (syngas), which consists primarily of a mixture of carbon monoxide and hydrogen. When configured to maximize the production of paraffinic hydrocarbons, the resulting intermediate product mix is often described as "synthetic crude oil" (syncrude).
Since most of world's gas reserves are in the form of relatively small fields that would be inadequate for world-scale Fischer-Tropsch gas-to-liquids (GTL) production capacities, interest is increasing in new and improved Fischer-Tropsch GTL production technologies that may be viable at low production capacities (below 10,000 bpd) because less than 10% of the world's gas fields are large enough to sustain a 10,000+ bpd Fischer-Tropsch GTL plant. Reducing the production rate to 2,000 bpd makes approximately 40% of gas fields viable sources. Also of particular interest would be process technologies that would enable Fischer-Tropsch GTL production on floating production, storage, and offloading (FPSO) vessels which are finding increased use in the development of oil fields in remote deep water tracts with no alternative economical outlet for associated gas.
The primary limitations of conventional Fischer-Tropsch GTL technology include the removal of process heat that can produce hot spots and severely shorten catalyst life, and effective management of two-phase flow as synthesis gas transforms into liquid hydrocarbons via Fischer-Tropsch chemistry. Both of these issues can be addressed with microchannel process technology, which improves heat transfer and controls flow through many parallel channels. When utilized in modular fashion, the application of microchannel process technology is a natural fit for converting associated gas into synthetic crude via the Fischer-Tropsch GTL process.
This PEP report reviews the leading technologies for sub-"world scale" production of natural gas-derived synthetic fuels via Fischer-Tropsch synthesis. Two gas-to-syncrude production process designs and their estimated production economics are presented, one of which is based on Syntroleum GTL technology, and the other is a modular GTL process based on microchannel technology offered by Velocys.