Gasification technologies convert coal and biomass into synthesis gas feed streams that can be used for power generation cycles or converted into value-added chemicals and transportation fuels. However, coal-derived synthesis gas contains many trace contaminants that should be removed prior to downstream processes. TDA Research, Inc. (TDA) is developing a low-cost, high capacity sorbent that can remove ammonia (NH3) and hydrogen cyanide (HCN) and trace metal contaminants (such as mercury, arsenic, and selenium) from coal- and coal/biomass-derived synthesis gas in a single process step. TDA will determine the effect of operating parameters, conduct multiple-cycle experiments, and test sorbent life. Unlike the commercially available gas clean-up technologies, the TDA multi-contaminant control system operates above the dew point of the synthesis gas (500 degrees Fahrenheit). With this technology, the synthesis gas would not have to be cooled in order to remove the contaminants, thus improving the thermal efficiency of the process. This technology has the potential to improve the energy efficiency and process economics for producing electric power from coal gasification.
Gasification is used to convert a solid feedstock, such as coal, petcoke, or biomass, into a gaseous form, referred to as synthesis gas or syngas, which is primarily hydrogen and carbon monoxide. With gasification-based technologies, pollutants can be captured and disposed of or converted to useful products. Gasification can generate clean power by adding steam to the syngas in a water-gas-shift reactor to convert the carbon monoxide to carbon dioxide (CO2) and to produce additional hydrogen. The hydrogen and CO2 are separated—the hydrogen is used to make power and the CO2 is sent to storage, converted to useful products or used for EOR. In addition to efficiently producing electric power, a wide range of transportation fuels and chemicals can be produced from the cleaned syngas, thereby providing the flexibility needed to capitalize on the changing economic market. As a result, gasification provides a flexible technology option for using domestically available resources while meeting future environmental emission standards. Polygeneration plants that produce multiple products are uniquely possible with gasification technologies. The Gasification Systems program is developing technologies in three key areas to reduce the cost and increase the efficiency of producing syngas: (1) Feed Systems, (2) Gasifier Optimization and Plant Supporting Systems, and (3) Syngas Processing Systems.
Syngas processing research and development underway emphasizes technologies that can be efficiently integrated into the plant, optimized with the temperature and pressure requirements of other systems, and meet product delivery specifications. A major cost element in gasification plants is converting raw syngas into a pure and specific gas used to create the plant's target product suite. High-hydrogen, low-methane, ultraclean syngas is versatile and can be used for power production with CO2 capture, fuels or chemicals production, and for many polygeneration applications. The technologies being developed are focused on high-efficiency processes that operate at moderate to high temperatures and clean syngas of all contaminants to the extremely low levels needed for chemical production—often significantly lower than the U.S. Environmental Protection Agency (EPA) required levels for power plants.
TDA’s is developing a low-cost, high capacity sorbent for use in their multi-contaminant control system. This technology has the potential to improve the energy efficiency and process economics for producing electric power from coal gasification because it can remove ammonia (NH3) and hydrogen cyanide (HCN) and trace metal contaminants (such as mercury, arsenic, and selenium) from coal and coal-biomass derived synthesis gas in a single process step and operates above the dew point of the synthesis gas (500 degrees Fahrenheit).
Click to view Presentations, Papers, and Publications