Novel Process Enhances Thermal Conversion of Shale Gas to Diesel
Several U.S. refineries in the 1920s and 1930s used thermal, non-catalytic conversions of light olefins in the production of motor fuels. However, the resulting fuels had relatively low octane levels and required harsh operating conditions, ultimately giving way to solid-acid catalytic processes.
CISTAR researchers at Purdue have demonstrated at the laboratory scale a thermal olefin conversion process selective for linear terminal olefin products for the second step of a two-step process operation needed to convert abundant US shale hydrocarbons to liquid transportation fuels. Thermal, non-catalytic, free-radical ethylene oligomerization at temperatures between 300oC and 500 oC and at pressures from 1.5 bar to 45 bar produced linearly terminal olefin products with only minor yields of side-products and coke. This process can be potentially applied to both large- and small-scale applications near the shale gas wellhead. As natural gas production increases, there is a potential $20 billion market for conversion of ethane, propane, and butane to liquid fuels. A patent on this technology has been licensed by one of the CISTAR industrial partners.