Rentech (RDC) announced today that it would purchase Royster-Clark Nitrogen of East Dubuqe, IL, a fertilizer producer, and convert the existing natural gas-fed plant to coal-fed gasification plant. The conversion calls for two gasification trains and a spare, standby gasifier, to process 5,200 tons per day of coal. The conversion will increase the capacity of the plant from 830 tons per day to 900 tons per day of nitrogen (in the form of ammonia) as well as producing 87 million gallons per year of Fischer-Tropsch (FT) liquid fuels and a surplus of electricity. The conversion is estimated to take three and one-half years. RDC will use the Conocco-Phillips gasification process with its slurry reactor, iron-based catalyst FT process. Rentech believes that when the project is completed it will be the first U.S. plant to produce commercial quantities of fuel using coal-to liquids (CTL) technology.
In its press release Rentech states:
The conversion will also address issues within the domestic nitrogen fertilizer industry which has suffered from high volatile natural gas prices since 1999. By co-producing nitrogen fertilizer, FT fuels and electricity from coal derived synthesis gas, RDC will be maximizing the thermal efficiency of the facility and utilizing the BTU output of the plant with the highest value products while in turn improving the profitability of the overall process.
Their website gives the following description of their technology:
Rentech is the developer and licensor of a patented and proprietary Fischer-Tropsch gas-to-liquids process (GTL) for conversion of synthesis gas made from natural gas, industrial off-gas, or solid or liquid carbon-bearing materials into high-value fuels and chemicals. They have successfully operated a 250 GPD pilot plant that has that proved the Company's commercial slurry reactor design and iron-based catalyst life. The three-step Rentech process converts first converts feedstock to synthesis gas. This synthesis gas is then sent to a slurry reactor that contains Rentech’s patented and proprietary iron catalyst. In this reactor the synthesis gas is converted to an ultra-low sulfur, ultra-low aromatic liquid that is then processed into various high-grade products such as fuels, solvents, waxes, or lube oil stock. They use a slurry reactor design with iron catalyst as it provides the lowest CAPEX and OPEX, high carbon conversion efficiency as well as the ability to convert the widest range of feedstocks.
This type of facility allows CTL technology to be developed on a relatively small scale while any kinks are worked out of the process. By producing nitrogen as the primary product, with electricity and FT liquids the process economics are improved considerably. Similarly DOE has conducted a study that indicated that adding a CTL stream to an IGCC electrical plant improves the economics of the total facility. This philosophy is used in the other coal-to liquids project in the US, the Gilberton project, where electricity is the primary product and FT liquids are the secondary product.