A pair of new technologies could reduce the cost of capturing carbon dioxide from coal plants and help utilities comply with existing and proposed environmental regulations, including requirements to reduce greenhouse-gas emissions. Both involve burning coal in the presence of pure oxygen rather than air, which is mostly nitrogen. Major companies including Toshiba, Shaw, and Itea have announced plans to build demonstration plants for the technologies in coming months.
The basic idea of burning fossil fuels in pure oxygen isn't new. The drawback is that it's more expensive than conventional coal plant technology, because it requires additional equipment to separate oxygen and nitrogen. The new technologies attempt to offset at least some of this cost by improving efficiency and reducing capital costs in other areas of a coal plant. Among other things, they simplify the after-treatment required to meet U.S. Environmental Protection Agency regulations.
One of the new technologies, which involves pressurizing the oxygen, is being developed by a partnership between ThermoEnergy, based in Worcester, Massachusetts, and the major Italian engineering firm Itea. A version of it has been demonstrated at a small plant in Singapore that can generate about 15 megawatts of heat (enough for about five megawatts of electricity).