流动布置方式对三分仓回转式空气预热器热力性能和硫酸氢铵沉积规律的影响

基于有限差分方法的回转式空气预热器热力计算模型,分析了在烟气顺流-逆流,二次风顺流-逆流,一次风顺流-逆流等流动布置方式下,流体和蓄热元件温度分布以及硫酸氢铵(ABS)沉积区域分布的变化规律。结果表明:当流动布置方式由逆流改为逆流-顺流混合型式后,流体与金属温度场分布改变显著。在二次风顺流-逆流,一次风顺流-逆流布置方式下,烟气分仓蓄热元件最高温度、最低温度以及平均温度随元件高度的分布曲线,随改变流向(顺流)空气流量比例的增加而趋于上凸;在烟气顺流-逆流布置方式下,烟气分仓蓄热元件最高温度、最低温度以及平均温度随元件高度的分布曲线,随改变流向(逆流)烟气流量比例的增加而趋于下凹;与采用烟气顺流-逆流布置方式相比,采用二次风顺流-逆流或一次风顺流-逆流布置方式,提高中温段和冷端平均壁温的效率更高,通过调节改变流向的流体流量比例,可以有效控制硫酸氢铵(ABS)沉积区域完全在吹灰通透性较好的冷端范围内,是更推荐的流动布置方式。

Influence of Flow Arrangement Pattern on Thermal Performance of Tri-sector Rotary Regenerative Air Pre-heater and Deposition Rule for Ammonium Bisulfate

The paper analyzed rules for temperature field distribution for fluids and metal components,and deposition area of ammonium bisulfate (ABS) of rotary air pre-heater under the flow arrangement patterns for parallel flow counter flow for flue gas,secondary air and primary air.The finite difference method is used in this study.The result shows that when flow arrangement pattern is changed from counter flow to mixed pattern for parallel flow-counter flow,distributions for fluid and metal temperature field change clearly.Under the arrangement patterns of parallel flow-counter flow of secondary air and primary air,the highest,lowest and average temperatures in the sectional regenerative heat storage component of flue gas tend to have a convex shape with the increase of air flow rate in the parallel flow.Under the arrangement pattern for parallel flow-counter flow of flue gas,the highest,lowest and average temperatures in sectional regenerative heat storage component of flue gas tend to have a concave shape with the increase of air flow rate in the parallel flow.Compared with the arrangement pattern subject to parallel flow-counter flow of flue gas,the efficiency for improving average wall temperature in medium temperature section and cold end is higher for the parallel flow-counter flow of secondary air or primary air,which can effectively ensure that deposition area for ammonium bisulfate (ABS) is totally within the cold end scope with relatively good transparency for soot blowing.This latter flow arrangement method is preferred and recommended.