Research In On Flow Field Optimization Control Of SCR Denitrification For 300MW Unit

Nox emission standards of coal-fired power plants have been gradually raised,and the denitrification transformation of coal-fired power plants has been basically completed in China.Most coal-fired power plants adopt selective catalytic reduction(SCR)for denitrification,mainly because of its high denitrification efficiency and relatively perfect technology.However,the application of this technology in China is relatively late,and some problems are encountered in the process of design,installation and use.In the long-term operation of 300 MW boiler,there are some problems,such as partial wear of rectifier grille and catalyst,low denitrification efficiency and high ammonia escape.Aiming at the uneven distribution of flow field and dust in SCR denitrification system of a 300 MW unit,three optimization schemes of inlet flue diversion device of SCR reactor were proposed based on the measurement results and numerical simulation results of denitrification system entrance.The numerical simulation results show that the pressure loss increases by 69 Pa,42 Pa and 25 Pa in turn compared with the original scheme.The uniformity of smoke and dust mass concentration distribution in the cross section above the catalyst is optimized scheme 2>optimized scheme 1>optimized scheme 3>prototype.The uniformity of smoke and gas flow field,smoke and dust concentration field and smoke and dust distribution with large particle size is considered comprehensively.The final transformation scheme is optimized.Program 2.After the implementation of the optimization scheme 2,the flue gas velocity at the measuring points of the inlet and outlet sections of the denitrification reactor was measured,and the simulation calculation of the flue gas concentration was carried out on the basis of this.The results show that the non-uniformity of smoke and dust concentration in the cross section above the catalyst decreases from 81.12%to 69.19%,which is better than the expected value(70.20%),the non-uniformity of flow field increases from 8.42%to 9.09%,which is 0.17%higher than the expected value(8.928%),and the pressure loss increases by 44 Pa.The modification effect is basically in line with the expected value.