|-- Introduction |-- Special Feature |-- Environment |-- Economy |-- Society |-- Integration |-- Others • Addendum |-- Report Site map Air Pollution Control Measures Control of sulfur oxides (SOx) Flue gas desulfurization facilities Flue gas desulfurization facilities, which cause SOx in flue gas to react with lime and thereby removes it (the wet limestone-gypsum process), have been installed in the No. 1 & 2 Reactors of Yokosuka Thermal Power Station. Though originally designed to complement fuel measures, more advanced flue gas desulfurization facilities have also been installed in Hitachinaka Thermal Power Station, which is exclusively fueled by coal. They are also due to be installed in the No. 5 & 6 Reactors of Hirono Thermal Power Station. Control of nitrogen oxides (NOx) Flue gas denitrification facilities Flue gas denitrification facilities inject ammonia into flue gas containing NOx, promote a chemical reaction through the effects of a catalyst, and degrade NOx into N2 and H2O (ammonia-based selective catalytic reduction). These facilities have been introduced into Chiba Thermal Power Station and Yokohama Thermal Power Station, among others. Improvement of combustion methods The following are representative examples of methods of reducing NOx emissions by controling the combustion temperature inside boilers or gas turbine burners. (1) Methods of improving combustion inside boilers  • The Flue Gas Recirculation Method A method of reducing oxygen density in combustion air by mixing some flue gas and thereby causing slower combustion.  • The 2-Stage Combustion Method A method of causing slower combustion by leading combustion air into the boiler in two stages (burner and over-air port).  • Low-NOx burners Burners that reduce the high-temperature burning area. (2) Methods of improving combustion inside gas turbines  • Premixed combustion system A method of mixing air and fuel before burning, therebysecuring uniform and stable combustion. Control of soot and dust emissions Electrostatic precipitators High-performance electrostatic precipitators have been installed in all thermal power stations (except those fueled exclusively by gas, which emit no soot or dust).