Rentech (AMEX: RTK) is a United States company engaged in development and commercialization of a patented and proprietary Fischer-Tropsch process for the conversion of various feedstocks to liquids fuels and chemicals. Rentech's process involves using a molten wax slurry reactor with an iron catalyst.

In 2009 Rentech acquired SilvaGas Inc and its biomass gasification system, which was developed in a partnership between Battelle Labs and the U.S. Department of Energy as part of their Biomass Power Program. The gasifier produced synthetic gas for power production at the McNeil Power Station in Burlington, VT, from 200 dry tons per day of wood chips. Rentech plans to use the renamed Rentech-SilvaGas gasification system in stand alone power production facilities and in bio-refineries.

Rentech's Product Demonstration Unit, located in Commerce City, Colorado, is the first fully integrated synthetic fuels and chemicals facility in the United States. The PDU started up and produced its first fuel during the summer of 2008. The PDU produces approximately 10 barrels per day (1.6 m³/d) of ultra-clean diesel, aviation fuels and naphtha. It is intended to serve as a testing ground for feedstock such as natural gas, petroleum coke and biomass, and as an end-to-end demonstration center for the production process of synthetic fuels.