基于CFD的某330MW燃煤机组SCR脱硝系统混合器优化与验证

为探明混合器形式对于燃煤机组SCR脱硝系统性能的影响，运用数值三维模拟对330 MW燃煤机组SCR脱硝系统烟道中烟气流动速度、温度、氨浓度以及流动方向进行了模拟计算，并采用物理模型对数值模拟结果进行验证。对比研究了使用不同形式混合器上下游速度场、NH₃浓度场、压力损失及加工难度。结果表明：梯形板混合器加工简单、扰动范围大、压力损失大、对下游速度场影响大；扭叶片式混合器阻力小、对下游速度场几乎没有影响，但扰动范围小、安装角度要求高；六角星形混合器综合性能介于梯形板及扭叶片式混合器之间。六角星形混合器能够较好地实现NH₃与烟气混合，下游速度场均匀性及NH₃浓度均匀性满足设计要求。

MICROMIXER IMPROVEMENT AND VERIFICATION FOR AN SCR DENITRATION SYSTEM OF A 330 MW COAL-FIRED POWER UNIT BASED ON CFD

In this paper, the flow velocity, temperature, ammonia concentration, and flow direction of flue gas in the SCR denitration system of a 330 MW coal-fired power unit were simulated by three-dimensional numerical simulation, and then the numerical simulation results were verified by a physical model. The results showed that the trapezoidal micromixer had the advantages of simple processing, large disturbance range, large pressure loss, and great influence on the downstream velocity field; the twisted vane micromixer had lower resistance and effect on the downstream velocity field, but smaller disturbance range and higher requirements on the installation angle. The comprehensive performance of hexagonal micromixer was between trapezoidal micromixer and twisted vane micromixer. The hexagonal micromixer could better realize the mixing of NH₃ and flue gas, and the uniformity of downstream velocity field and NH₃ concentration met the design requirements.