Flue-gas NO/sub x/ removal system operates on coal-fired power plant

A selective catalytic-reduction (SCR) device may advance nitrogen oxide emission control technology enough to retain high power plant standards even if the regulations are relaxed. After successful testing of the SCR at Japanese coal-fired plants, the technology is well developed and the system is commercially available. The flue gas stream is sprayed with ammonia, which reacts with nitrogen oxide to form gaseous nitrogen and water. The cost of annually replacing the titanium oxide and vanadium oxide catalyst is a major problem of the system. Local emission regulations are tougher in Japan and are expected to be even more stringent as the coal conversion process proceeds. Facing the problem of lowering both nitrogen and sulfur oxide emissions to reduce acid rain, government policies show a definite trend toward putting the burden on power plants because the technology is more advanced than for automobile emissions. (DCK)