空预器冷端再热防堵技术的数值模拟研究及应用

Numerical Simulation and Application of Reheating Anti⁃blocking Technology in Cold Segment of Preheater

为了解决空预器堵塞问题,确定了以热二次风为热源的冷端再热防堵方案,其中再热分仓设置在二次风侧与烟气侧之间。搭建了空预器冷端再热数值计算模型,对50%BMCR工况下的冷端再热参数进行了数值模拟验证,并进行了实际改造应用。数值计算结果表明:50%BMCR工况下,再热风量为80 t/h时,可保证空预器再热分仓温度稳定在200℃以上,进而抑制硫酸氢铵沉积。实际应用结果表明:改造后,空预器差压可以长期维持1.0 kPa以下,同时降低排烟温度3~5℃,提高的一次风温、二次风温分别为2℃和3℃,提高了机组运行的经济性。

In order to solve the blocking problem of the air preheater,a cold segment reheating anti⁃blocking scheme with hot secondary air as the heat source was released,in which the reheat sub⁃silo was set between the secondary air silo and the flue gas silo.The numerical calculation model of the cold segment reheat is built,and the numerical simulation of the cold segment reheat parameters on the 50%BMCR condition are carried out,and the practical application has done.The numerical calculation results show that:on 50%BMCR condition,when the reheat air volume is 80t/h,the temperature of the air preheater reheat sub⁃silo can be guaranteed to be stable above 200℃,thereby inhibiting the deposition of am⁃monium hydrogen sulfate.The practical application results show that:after the transformation,the differential pressure of the air preheater can be maintained below 1.0kPa for a long time,while the exhaust gas temperature is reduced by 3~5℃.And the primary air temperature and the secondary air temperature are increased by 2℃and 3℃respectively,the transformation enhanced the economy of unit operation.