CCS and Power Systems
Advanced Energy Systems - Gasification Systems
Coal - Carbon Dioxide (CO2) Slurry Feeding System for Pressurized Gasifiers
Performer: Massachusetts Institute of Technology
Project No: FE0012500
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.
Feed systems research is underway to reduce the cost and increase the efficiency, through design and advanced plant integration, of fuel and oxygen feed to commercial gasifiers. High-pressure solid feed systems will expand the use of our nation's Western low-cost, low-rank coals for high-pressure gasifiers (currently limited to more expensive fuel), enable co-feeding of coal with other advantageous fuels (such as biomass), and encourage higher pressure (and therefore more efficient) operation of dry feed gasifiers. ITM technology will lower the cost of oxygen production through reduced capital costs, and result in more efficient IGCC power plants through turbine integration, as compared to today's commercially available, energy intensive technology for oxygen production—cryogenic air separation.
The Massachusetts Institute of Technology project is developing and assessing a coal-CO2 slurry feeding system. As opposed to conventional coal-water slurry feeding, the coal-CO2 slurry feeding approach avoids the thermal efficiency loss incurred by addition of slurry water, particularly when feeding low-rank coals already high in moisture content, and allows high-pressure operation while avoiding the high capital cost and limited pressure range of dry coal feeding using lock-hopper technology. This new coal feeding method has the potential to improve the efficiency and economics of coal-based power generation with carbon capture and reduce the costs of converting coal to gasoline and diesel fuels.