PROGRAM AREA OVERVIEW --

10. Coal Gasification Technologies

Coal gasification offers a versatile and clean way to convert the energy content of coal into electricity, hydrogen, other high quality transportation fuels, and high-value chemicals to meet specific market needs. Most importantly, in a time of electricity and fuel price spikes, flexible gasification systems can provide a capability to operate on low-cost, widely-available feedstocks. Gasification may be one of the best ways to produce clean-burning hydrogen for tomorrow's automobiles and power-generating fuel cells. Hydrogen and other coal gases can also be used to fuel power-generating turbines or as the chemical "building blocks" for a wide range of commercial products. The Office of Fossil Energy is working on coal gasifier technology advances that enhance efficiency, environmental performance, and reliability. Grant applications are sought only for the following subtopics:

a. Technologies to Produce High-Value Added Products from Coal Gasification—The positive economic impact of technologies that produce high value-added products and/or materials from the coal gasification process and its byproducts would expedite the development of coal gasification. For this subtopic, grant applications are sought for novel technologies to convert coal gasification byproduct(s) into a value-added material. Of particular interest are innovative technologies that maximize the value of byproducts from inferior coal gasification feedstocks, such as high-sulfur coal, or a mixture containing at least 75% coal along with biomass and/or municipal/industrial waste. Approaches should include laboratory-scale experimentation aimed at defining the critical processes applicable to the creation of value-added materials. Grant applications should describe how the value-added material will be used and identify likely end users or markets. In addition, downstream plans for commercializing the value-added material/product should be addressed, along with how the remaining non-value-added byproducts will be handled in an environmentally-friendly manner.

b. Improved Methods for Cleanup of Multiple Contaminants—Grant applications are sought for cleaning/conditioning of the synthesis gas produced from the gasification of carbonaceous fuels in advanced power systems, hydrogen production, and chemical/liquid fuel production, at significantly reduced capital and operating cost. Proposed technologies may be conceptual or experimental, but must have the potential to remove multiple syngas contaminants to near zero limits, due both to environmental considerations and to prevent fouling of downstream equipment and/or catalysts. Contaminants of interest are Hg, As, Se, Cd, NH₃, and Cl. Process conditions of interest include temperatures from 400ºF to 700ºF and pressures from 300 to 1000 psi.

Of particular interest are multi-contaminant control concepts that result in a significant reduction in the number of unit operations and processes. All approaches must be economically attractive and minimize loss of, but preferably increase, overall system efficiency.

c. Novel Concepts in Air Separation (Non-Cryogenic)—Oxygen is the third largest commodity chemical in the U.S., with an annual market over $2B. However, the high cost of oxygen has been a barrier to the widespread application of oxygen-enriched combustion and oxygen-blown gasification in coal-fired power plants. Grant applications are sought to develop new concepts for the non-cryogenic separation of oxygen from air at temperatures ranging from ambient to 900ºC. Some approaches of interest include the development of: (1) novel membrane compositions including, but not limited to, inorganic, ceramic, or porous materials or a combination thereof – approaches may include first producing oxygen-rich air, followed by cost-effective separation of the oxygen to commercial purity by a different technique; (2) oxidation-reduction approaches using appropriate oxygen carriers, including new approaches for enhancing the intrinsic oxygen storage capacity of candidate carriers; (3) catalytic porous substrates for depositing thin-films of oxygen conductors, in order to improve oxygen separation flux; and (4) advanced oxygen storage materials that are mechanically stable through thermal and pressure cycles, in order to improve the performance of the chemical looping technique. Grant applications must describe the potential economic advantage of the proposed technology over conventional cryogenic air separation processes.

d. Novel Gasifier Concepts—Current commercial gasification systems, based on concepts developed many years ago, use steam gasification at high temperature and elevated pressure to produce a mixture of hydrogen and carbon monoxide. Unfortunately, many problems remain. The high temperatures cause significant materials problems. The elevated pressure makes solids feeding difficult: lock hoppers are expensive and often problematic. The need to use water slurry feed systems to smoothly carry the coal into the gasifier results in efficiency losses, but is a common feed mechanism because its reliability is critical for profitable gasifier operation (a problem exacerbated with low ranked coal because of its high water content). Overall, these processes are mechanically complex, leading to high capital costs, long construction times, and significant downtime for repairs. To make matters worse, the syngas from current commercial gasification systems is contaminated with trace metals and small amounts of such gases as hydrogen cyanide, hydrogen chloride, nitrogen, sulfur, and even carbon dioxide. To address these problems, grant applications are sought to develop: (1) gasifiers that operate at lower temperatures and pressures and/or produce a cleaner syngas product, and (2) novel gasifier feed systems. Grant applications also are sought to develop gasifiers that produce syngas with high hydrogen or methane content; such fuels would help meet the needs of the hydrogen economy and will be more directly compatible with fuel cells.

Finally, grant applications are sought to develop small gasifiers with less than 100 MWe equivalent capacity, or to improve the economics of existing small scale gasifiers. Smaller gasifiers can be used to meet the needs of distributed generation and allow the use of opportunity fuels that exist in smaller quantities in some locations. Designs for small scale systems must address the loss of economy-of-scale advantages and consider the overall economics for these small scale power and/or poly-generation applications.

For this solicitation, gasifiers must use coal for at least 75% of their fuel input. Grant applications submitted under this subtopic should include carefully crafted laboratory-scale experimentation aimed at defining the critical processes that control the proposed gasification concept. Applications must describe how successful development will result in lower cost and more efficient gasifier operation, compared to conventional systems.

References:

1. Gasification Technologies, U.S. Department of Energy (DOE), National Energy Technology Laboratory Web site. (http://www.netl.doe.gov/coal/. In the circle at the center of the page, select “Gasification Technologies.”)

2. Gasification Technology R&D, U.S. DOE Office of Fossil Energy Web site. (http://fossil.energy.gov/programs/powersystems/gasification/)

3. Carbon Capture Research, U.S. Department of Energy, Office of Fossil Energy Web site. (http://fossil.energy.gov/programs/sequestration/capture/)

4. “FutureGen - A Sequestration and Hydrogen Research Initiative,” U.S. Department of Energy, Office of Fossil Energy, February 2003. (http://fossil.energy.gov/programs/powersystems/futuregen/futuregen_factsheet.pdf)

5. Hydrogen and Other Clean Fuels, U.S. DOE Office of Fossil Energy Web site. (http://fossil.energy.gov/programs/fuels/)

6. Browning, G. J., et al., “The Effects of Heterogeneous Slag Character on Viscosity and Slag Flow in IGCC Gasifiers,” International Flame Research Foundation Combustion Journal, Communication No. 199901, December 1999. (ISSN: 1562-479X) (Full text available at: http://www.journal.ifrf.net/199901browning.html.

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