Low NO{sub x} bituminous coal firing systems for large steam generators

The environmental legislation in Germany for large scale coal fired steam generators requires a limit for the NO{sub x} emissions of 200 mg/m{sup 3} [97.56 ppm] (standard temperature and pressure, dry, 6% O{sub 2}). For lignite fired plants this limit can be achieved by pure primary side measures. Bituminous coal fired steam generators, however, have to be equipped with SCR plants in order to reduce the primary NO{sub x} emissions. It is pointed out in this paper that despite the existence of SCR plants, there are economic incentives to reduce further the primary NO{sub x} emissions. Additionally the milestones of the realization of the EVT low NO{sub x} firing system are high-lighted as well. These milestones comprise experiments in an entrained flow reactor, studies in computational reactive fluid dynamics of full scale furnaces, and the operation results after the realization in a power plant with 110 MW{sub el}. Also the scale-up to a steam generator unit with 750 MW{sub el} has been outlined. In the meantime for this plant the EVT low NO{sub x} firing system has been successfully realized and thus the NO{sub x} emissions could be reduced from 415 ppm (before modification) to below the guaranteed value ofmore » 170 ppm (s.t.p., dry, 6% O{sub 2}).« less