Rentech has ordered the gasifier and product upgrading units needed for the Fischer-Tropsch (FT) Coal-to-Liquids (CTL) Product Development Unit (PDU) it will be building at the Sand Creek facility in Commerce City, Colorado near Denver. (Earlier post.)
The PDU has been engineered to produce 10-15 barrels per day of FT diesel, naphtha and jet fuel through the Rentech CTL process technology.
A gasifier from BioConversion Technology, LLC capable of processing 25-35 tons per day of coal will provide the synthesis gas (a combination of hydrogen and carbon monoxide). Rentech will primarily process eastern and western coal at the facility with the capability to also process petroleum coke as well as biomass.
|Klepper gasification system|
BioConversion Technology uses a gasification technology it calls the Klepper Pyrolytic Steam Reforming Gasifier (PSRG) with a Staged Temperature Reaction Process (STRP). (The company also offers the Klepper Ethanol Reactor which catalytically converts syngas into ethanol. BioConversion Technology is Robert (Bud) Klepper’s company.)
The Klepper PSRG with STRP system typically generates syngas from coal, coal slurry, coal fines and other biomass feedstocks with energy content in the range of 400–600 BTU/ft3 at an average thermal energy conversion efficiency of 75%.
The Klepper system has the highest energy efficiency of any system and the highest syngas energy content of any thermochemical biomass conversion system that has been developed for biomass inputs of less than 1,000 tons/day, according to a comparative evaluation of such systems performed for the East Bay Municipal Utility District in Oakland, California.
The Klepper PSRG with STRP employs an entrained flow principle (using a gas to propel the pulverized feedstock through the direct fired reaction zone) but features two separate reactors: a devolitization reactor and a reforming reactor.
The devolitization reactor slowly raises the temperature of the feed material through 450°F (the temperature at which combustion will occur) until a substantial portion of the oxygen has reacted with more reactive material in the feed.
Once the available oxygen has been reacted at below combustion temperature, the feed material temperature is raised to a higher temperature, for example 650°F, prior to combination with super heated steam (1,500°F) and a subsequent rise in temperature to react with the carbonaceous feed material and produce the CO- and H2-rich syngas.
The Klepper system uses the produced syngas and process steam to propel the feedstock through the segregated steam reforming reactor. Among other things, this technique raises the calorific value of the syngas by not diluting the product syngas with nitrogen or carbon dioxide as is the case with an air-blown gasifier. Nor does it require a costly separate supply of oxygen or the elevated temperatures and “run-away” pyrolysis issues associated with the use of an oxygen-blown gasifier.
This multi-stage approach results in a very high conversion efficiency, while at the same time, keeping the tar content in the produced gas extremely low. Another unique feature specific to the Klepper system is that the cyclones and water condenser are integrated and contained within the biomass gasification chamber. This design conserves space and reduces the loss of heat energy.
The product upgrading system will be engineered and fabricated by Zeton, Inc.
The Sand Creek site, which originally operated as a methanol facility, will have the existing natural gas reformer and methanol synthesis unit removed. All of the associated product storage tanks and some utilities will be retained.
Rentech plans to begin site construction—assuming it clears the state and local permitting process—in the second calendar quarter of 2006. The company believes that the integrated CTL facility will be ready for commissioning and startup in the fourth calendar quarter of 2006.
The facility will provide test quantities of FT fuels to numerous groups which have expressed a strong interest in acquiring commercial quantities of Rentech’s fuels, including the Department of Defense; major metropolitan areas such as Chicago and Houston; and state and local government entities in California, Illinois, Ohio, Montana and Wyoming.
BioConversion Technology: Clean Coal Without Compromise