Process development and demonstration of coal and biomass indirect liquefaction to synthetic iso-paraffinic kerosene

To demonstrate coal- and biomass-to-liquid (CBTL) hydrocarbon fuel technology, a supported, iron-based Fischer–Tropsch (FT) catalyst was developed. The catalyst preparation procedure was optimized and then scaled up to produce 2 kg of catalyst to fill a pilot-scale FT reactor system. Synthesis gas was produced from a fluidized-bed gasification system that is capable of processing up to 9 kg/h of coal and biomass. Impurities from the raw syngas such as sulfur, tars, and particulate matter were reduced to levels that would not significantly diminish FT catalyst performance. The gasification and FT reactor systems were operated continuously for 5 days on feed stocks consisting of sub-bituminous coal and blends of coal and various biomass sources such as olive pits, switchgrass, and dried distillers' grain. Liquid and wax hydrocarbon products were collected and subsequently upgraded into synthetic isoparaffinic kerosene, which used elements of a proprietary process for converting crop oils into jet fuel. The finished fuel very nearly met specifications for synthetic military-grade isoparaffinic kerosene.

► Fe–Cu–K–La Fischer–Tropsch catalysts on bimodal alumina supports were developed.
► FT catalysts were tested in a lab reactor and optimum conditions were selected.
► FT catalyst was tested in a pilot reactor with coal/biomass derived syngas.
► FT liquids were upgraded to specification compliant jet fuel.