低温烟气脱硝旋流流化反应器的传热特性

Heat transfer characteristics of low-temperature flue gas denitrification swirlfluidization reactor

现行工业低温烟气脱硝技术需对烟气及整个反应系统进行整体加热以达到催化剂高效反应的温度,存在能耗高的问题。由于脱硝反应仅在高温催化颗粒的微界面上进行,提出以高温催化剂颗粒为循环热载体,利用旋流流化反应器使其与低温烟气中的氮氧化物快速接触,发生脱硝反应的新方法。通过CFD和DEM耦合计算,模拟研究了旋流流化反应器中高温催化剂颗粒和低温烟气间的传热特性。调控因素主要包括进口气速、进料速率、进口烟气温度。结果表明,在催化剂进料速率为25 g·s^(-1)、进口气速为7.5 m·s^(-1)(空速81000 h^(-1))时,反应器出口催化剂平均温度可达200℃以上(催化剂高效活性温度区间为200~300℃),对比直接加热低温烟气的方式,不考虑加热与传热过程热量损失,可直接节约能耗28.36%。本研究对比低温烟气脱硝中整体加热烟气的方式,可为低温烟气脱硝技术的优化提供参考。

At present,for industrial low-temperature flue gas denitrification,the flue gas and the whole reaction system is heated to achieve the efficient reaction temperature of the catalyst,the overall energy consumption of whihc is high.Based on the denitrification reaction on the face of high-temperature catalytic particles,a new method for rapid reaction with nitrogen oxides in low-temperature flue gas in a cyclone fluidization reactor using high-temperature catalyst particles as the circulating heat carrier was proposed.Through the coupling calculation of CFD and DEM,the heat transfer characteristics between high-temperature catalyst particles and low-temperature flue gas in the cyclone fluidization reactor were simulated and studied,and the regulatory factors mainly included inlet gas velocity,feed rate and inlet flue gas temperature.The results showed that when the catalyst feed rate was 25 g·s^(-1)and the inlet gas velocity was 7.5 m·s^(-1)(airspeed 81000 h^(-1)),the average temperature of the catalyst outlet of the reactor could reach more than 200°C(the efficient active interval of the catalyst was 200~300°C).Compared with the direct heating of low-temperature flue gas,the direct energy consumption saving reached 28.36%without considering the heat loss in the heating and heat transfer process.