With an eye toward the development of cleaner coal-derived liquid fuels that can someday power cars, trucks, tanks, and even jets, the National Energy Technology Laboratory (NETL) has been supporting researchers at the University of Kentucky as they close in on an innovation that could someday advance the state of the art for transportation fuels production.

In an ongoing 5-year project, the researchers have advanced the design, construction, and operation of a small-scale pilot plant that gasifies coal and coal/biomass blends to form syngas (a mixture of carbon monoxide and hydrogen) and then converts the syngas to liquid fuels. The facility, located at the University of Kentucky’s Center for Applied Energy Research, has a 1‑barrel‑per‑day liquids fuel capacity and is intended to develop meaningful information about the technology; its scalability, cost, and economics; and product characteristics and quality.

The process centers upon a technology that has its roots in 1920s Germany, when scientists discovered a way to convert coal-derived syngas into liquid hydrocarbons. The process is called Fischer-Tropsch synthesis. Researchers at the Kentucky pilot plant feed coal-derived syngas from a gasifier to a Fischer-Tropsch process reactor where it is reacted over a catalyst to produce what is called Fischer-Tropsch wax. The wax is then “cracked” to the desired range of liquid hydrocarbons. The overall process converts coal into a liquid product that can be refined into liquid fuel suitable for use in a range of applications.

In coal-to-liquids technologies, emissions are avoided by removing certain constituents, such as sulfur, during the gasification process. In addition, the gasification process uses oxygen instead of air to produce the syngas, which allows carbon dioxide to be more easily stripped away. As a result, coal-to-liquids fuel products are considered clean-burning.

The NETL-supported project is advancing scientific knowledge about the production of liquid hydrocarbon fuels from coal and/or coal-biomass mixtures. The work is also identifying efficient and clean ways to handle and process coal/biomass mixtures, ensuring that those mixtures are compatible with delivery systems and amenable to efficient gasifier operations.