A significant reduction in air pollutants emitted by coal-fired power plants is achievable with oxy-circulating Oxy-circulating fluidized bed combustion system can separate carbon dioxide during the combustion process, use various types of fuels and significantly reduce exhaust gas and air pollutants emission. Source: Korea Institute of Energy Research fluidized bed combustion technology advanced by researchers in South Korea.

The combustion system enables separation of carbon dioxide, accepts low grade fuels and markedly reduces emissions of sulfur oxides and nitrogen oxides by combining oxy-combustion and circulating fluidized bed processes. Biomass is cofired with coal at temperatures up to 950° C using pure oxygen instead of air.

Experiments conducted in a test rig demonstrated greater pollutant emission reductions with oxygen versus air-firing. Nitrogen oxides, sulfur dioxide and carbon monoxide reductions of 29%, 31% and 18%, respectively, were documented with 24% volume oxygen. Carbon dioxide concentrations in flue gas are reduced by 90%, and thermal input can increase from 100 kW to 200 kW thermal when the oxygen concentration increases from 21% to 60%

The elevated oxygen concentration used plays a critical role in improving the combustion system's efficiency. While current technology uses oxygen concentrations at the 40% level, increasing the concentration to 60% or greater can translate into smaller-sized, stackless combustion facilities with relatively lower capital and operating costs.

Researchers from the National Research Council of Science & Technology, Korea Institute of Energy Research, Korea Institute of Industrial Technology, Korea Research Institute of Standards and Science and Korea Institute of Machinery and Materials contributed to this development.