MIT develops initial step toward carbon sequestration

Results: MIT researchers have developed designs for a new kind of coal-burning power plant, called a pressurized oxy-fuel combustion system, whose carbon-dioxide emissions are concentrated and pressurized so that they can be injected into deep geological formations. This system is a way to reduce the energy penalty that all carbon-capture systems for power plants have compared to regular fossil-fuel plants, and could thus be an enabling technology to help make carbon capture and sequestration systems (CCS) practical and affordable. While all carbon capture systems incur about a one-third reduction in plant efficiency, this system reduces that penalty.

Why it matters: Since more than 90 percent of world energy production uses fossil fuels, finding ways to burn them without adding greenhouse gases to the atmosphere is seen a crucial step toward curbing global climate change. The new system not only would eliminate the carbon dioxide emissions from the plant, but could produce savings by reducing the size of some components in the plant.

How they did it: Professor of mechanical engineering Ahmed Ghoniem and his team designed a coal-plant combustion chamber that burns the fuel under pressure, and uses a stream of pure oxygen instead of ordinary air, which is 79 percent nitrogen. They did both simulations and lab-scale tests of the new system to demonstrate a 3 percent improvement in efficiency compared to an unpressurized oxy-fuel system.

Next steps: The Italian energy company ENEL, which sponsored the research, plans to build a pilot plant using the system in the next few years. In the meantime, Ghoniem and his team are continuing to fine-tune the technology, hoping to improve the energy efficiency improvement to 10 to 15 percent.

Funding: Funding was provided by ENEL of Italy.

*** For longer version of the story, please visit: http://web.mit.edu/newsoffice/2009/oxyfuel-coal.html ***

Source: “Analysis of oxy-fuel combustion power cycle using a pressurized coal combustor,” by Jongsup Hong, Ahmed Ghoniem, et al, in Energy, August 2009.

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