CCS and Power Systems
Advanced Energy Systems - Gasification Systems
Advanced Acid Gas Separation Technology for Clean Power and Syngas Applications
Performer: Air Products and Chemicals, Inc.
Project No: FE0013363
Program Background and Project Benefits
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.
Air Products has developed a proprietary alternative to conventional syngas cleanup, combining a Sour Pressure Swing Adsorption (PSA) step that separates CO2 and H2S from the desired products, and a tailgas disposition block which separates the sulfur-containing compounds and purifies the CO2 to a sequestration-grade product. Specifically, Air Products will test a two-bed PSA unit on a slipstream of authentic, high-hydrogen syngas based on low-rank coal at the National Carbon Capture Center; also a multi-bed process development unit (PDU) will be operated, refining the reliability of predictions of PSA performance at commercial scale. The information obtained from the two-bed PSA unit and the PDU will be combined to build a techno-economic assessment of PSA utilization for methanol production, as well as to update techno-economic assessments of the technology for IGCC.