SCR脱硝反应器烟道内部流场的数值模拟与优化

Simulated calculation and optimization of internal flow field of selective catalytic reduction denitrification reactor flue

为优化无锡某电厂选择性催化还原脱硝反应器烟道内部流场,研究导流板和整流器对流场的影响,基于FLUENT软件和SIMPLE算法,采用RNG k-ε湍流模型和离散相模型数值模拟导流装置安装前、安装后和优化后3种情况下的烟道内部气流流动和固体颗粒流动。研究表明,导流板可以改善烟道内气流分布,同时保证气流进入催化剂层前的速度小于6 m/s,速度不均匀系数小于15%;整流器对改善气流流动、避免涡流存在具有重要作用,且对压降影响较小;合理的导流板结构和布置可以有效减小压降,导流板优化后压降降低至109.9 Pa。

In order to optimize the internal flow field of selective catalytic reduction( SCR) denitrification reactor flue of a certain power plant in Wuxi and to study the influences of deflectors and flow adjuster,RNG k-ε turbulence model and discrete model were adopted,based on software FLUENT and SIMPLE algorithm,to calculate the flow of flue gas and solid particles under three cases,that is,before installation,after installation,after optimization of guide devices. Results show that deflectors can improve the distribution of flue gas and they can also ensure that the gas velocity and nonuniform coefficient are below 6 m / s and 15%,respectively before gas entering the catalyst layer; flow adjuster is important to improve the flue gas flow and avoid vortex existence,and it affects pressure drop tinily; reasonable structures and arrangements of deflectors can reduce effectively the pressure drop which minishes to 109. 9 Pa after optimization.