Abstract:Based on the condition of a subcritical 600MW selective catalytic reduction (SCR) abnormal large ammonia consumption, denitration system operation difficult, NOx large fluctuation and air preheater blockage and other problems, the author analyzed the outlet  NOxdensity and flow field. By adjusting ammonia injection grid, the unit operation was optimized, density field was almost equally distributed. Testing point deviation was lowered to under 15%. Decreasing of air preheater resistance pressure difference reach to 26.13%.

Keywords:600MW unit, subcritical unit, boiler, denitration, SCR improvement, NOx density;flow field;air preheater