660MW燃煤机组SCR流场模拟优化与喷氨优化运行

Optimization of flow and ammonia injection by numerical simulation of SCR for a 660 MW coal-fired unit

以某电厂660 MW亚临界燃煤机组SCR烟气脱硝系统为研究对象,对SCR反应器内烟气流动以及喷氨分布均匀性进行数值模拟研究。通过对比首层催化剂前烟气速度分布及NH_3浓度分布,研究了SCR反应器内均流部件对烟气流场均匀特性的影响,并且在数值模拟的基础上对喷氨方式进行了优化调整研究。研究结果表明:优化调整烟道内均流部件对速度、浓度均匀性有显著改善作用;通过分析流场不均匀性得到的分区喷氨方法能够进一步优化NH_3在烟道中分布;现场试验验证了调节喷氨格栅阀门可降低SCR反应器出口NO_x浓度。本文研究可为燃煤机组SCR系统导流板优化及实际电厂喷氨优化调试提供参考。

Selective catalytic reduction（ SCR） is the most widely used denitration technology.A numerical study was carried out to evaluate the uniformity of gas flow and ammonia injection in the SCR denitration system of a 660 MW coal-fired unit.The influence of arrangement and structure of deflector on flow field in the system was investigated through comparing the uniformity of flue gas velocity and NH3 concentration distribution in the top catalyst layer.The optimized ammonia injection mode was also studied based on the numerical simulation.Results show that the optimization of arrangement and structure of deflectors significantly improved the uniformity of flue field and NH3 concentration distribution.The distribution of NH3 concentration in the top catalyst layer was further optimized by the partitional ammonia injection mode,which produced through the simulation results.And the site tests verify that the outlet NOx concentration of the SCR system was reduced by the control of the valve of ammonia injection grid.This paper aims to provide an optimized method of deflector and ammonia injection mode for the SCR system of power plant.