|The Rentech Process is based on Fischer-Tropsch chemistry. Click to enlarge.
The Rialto Renewable Energy Center (Rialto Project) is designed to produce approximately 600 barrels per day of renewable synthetic fuels and export approximately 35 MW of renewable electric power. The carbon footprint of the plant is designed to be near zero as the fuels and power would be produced only from renewable feedstocks.
RenDiesel, the renewable synthetic diesel to be produced at the facility, meets all applicable fuels standards, is compatible with existing engines and pipelines and burns cleanly, with emissions of particulates and other regulated pollutants significantly lower than the emissions from the combustion of CARB ultra-low sulfur diesel. The low carbon footprint of RenDiesel would help the transportation sector meet targets established by the Low Carbon Fuel Standard.
The power generated by the Rialto Project is expected to qualify under California’s Renewable Portfolio Standard (RPS) program, which requires utilities to increase the amount of electric power they sell from qualified renewable-energy resources. The plant will be capable of providing enough electricity for approximately 30,000 homes.
Rentech has entered into a licensing agreement with SilvaGas Corporation for biomass gasification technology for the Rialto facility. Between 1998 and 2001, a 400 ton-per-day plant using the SilvaGas biomass gasification technology successfully operated in Burlington, VT, producing synthesis gas (syngas) from wood-based biomass in a series of operating campaigns.
That plant was built in partnership with the US Department of Energy, Battelle Columbus Laboratory and the National Renewable Energy Laboratory (NREL).
The Battelle Memorial Institute originally developed the “Low Gas Inlet Velocity High Throughput Gasification Process” in the 1980s. This process is now known as the SilvaGas process.
The conditioned syngas will be converted by the Rentech Process in a commercial scale reactor to finished, ultra-clean products such as synthetic diesel and naphtha using upgrading technologies under an alliance between Rentech and UOP, a Honeywell Company. (Earlier post.)
|The Rentech reactor. Click to enlarge.
The Rentech Process uses a slurry bubble column reactor. Synthesis gas is fed into the bottom of the reactor where it is mixed with liquid wax and Rentech’s proprietary iron-based catalyst. The catalyst and wax are collectively referred to as slurry.
The reaction is exothermic and steam is generated in the internals of the reactor to produce steam and to remove heat and control the reaction temperature.
While some other Fischer-Tropsch technologies use a fixed bed reactor, Rentech says the slurry bubble reactor as it is simpler in design, less expensive to build and operate, and also provides for an easier scale up than the fixed-bed reactor. Additionally, Rentech believes that a slurry-bed reactor provides better product yield than the alternative.
Renewable electric power will be produced at the facility by using conventional high-efficiency gas turbine technology. The power is anticipated to be sold to local utilities under the California RPS program.
Having completed preliminary scoping studies, Rentech has engaged Jacobs Engineering Group Inc. to conduct the feasibility engineering phase of the project, which is expected to be completed over the next several months. This work will advance project development activities including preliminary design and plot plans and provide construction cost estimates that would then continue to be refined throughout the subsequent detailed engineering phases of the project. Based on the range of current preliminary scoping cost and yield estimates, the Rialto Project is expected to provide rates of return that would make the project commercially viable.
Rentech has an exclusive option on a site for the Rialto Project within the proposed Rialto Eco-Industrial Park, which is located adjacent to an existing City of Rialto Wastewater Treatment Plant and EnerTech Environmental Regional Bio-Solids Processing Facility. The location allows the proposed Rialto Facility to take advantage of established infrastructure including access to water, wastewater disposal and zoning.
The primary feedstock for the Rialto Project will be urban woody green waste such as yard clippings, for which Rentech is currently negotiating supply agreements. The location of the project will provide local green waste haulers with a cost-effective alternative to increasingly scarce landfills for the disposal of woody green waste. The plant is designed to also use biosolids for a portion of the feedstock which is expected to be provided under a supply agreement with EnerTech Environmental.
We expect the Rialto Project to be the prototype for many waste-to-fuels projects for Rentech. These projects are being designed at smaller scale than fossil-based projects, and feedstock costs are low or negative, resulting in significant potential returns on investment.—Doug Miller, Executive Vice President of Renewable Energy Businesses for Rentech
In 2005, Rentech acquired a Royster-Clark nitrogen fertilizer plant in East Dubuque, Illinois, in a $50-million deal for a platform for Rentech’s polygeneration strategy: the co-production of fertilizer, Fischer-Tropsch synthetic fuels and electric power via coal gasification. (Earlier post.)