膜式水冷壁结构燃磷塔的开发与传质传热的数值模拟(Ⅱ)传热特性影响因素分析

Simulation of mass and heat transfer in new phosphoric acid tower with circular water wall(Ⅱ) Analysis of influence on heat transfer

利用已建立的数学模型考察了燃磷量、过剩空气系数、壁面温度、辐射吸收系数对新型燃磷塔的最高燃烧温度、烟气排放温度、壁面最大热流和平均热流的影响.模拟结果表明,无论过剩空气系数固定还是空气流量固定,随燃磷量的增大,最高燃烧温度、烟气出口温度、壁面平均热流和最大热流都呈上升趋势.在燃磷量不变情况下,最高燃烧温度、壁面最大热流和平均热流均随过剩空气系数的增大而减小,但烟气出口温度缓慢增加.壁面温度对最高燃烧温度、壁面最大热流和平均热流影响不明显,但烟气出口温度随壁面温度的升高而增加较大.辐射吸收系数对最高燃烧温度和壁面最大热流影响很大,随辐射吸收系数的增大,最高燃烧温度和烟气出口温度会下降,而壁面最大热流和平均热流会上升.

The effects of parameters on maximum combustion temperature, smog exit temperature, maximum wall heat flux, averaged wall heat flux of a new phosphoric acid tower with circular water wall were discussed, including phosphorus consumption, excess air coefficient, wall temperature and radiation absorption coefficient, with the mathematical model developed in Part Ⅰ. The predicted results showed that maximum combustion temperature, smog exit temperature, maximum wall heat flux and averaged wall heat flux would increase with increasing phosphorus mass flow rate when excess-air coefficient or air flow rate was constant. Under the condition of constant phosphorus mass flow rate, the smog exit temperature would increase slowly while other parameters would decrease with increasing excess air coefficient. Wall temperature had a remarkable effect on smog exit temperature, whereas its effect on other parameters was not obvious. In addition, radiation absorption coefficient had a remarkable effect on maximum combustion temperature and maximum wall heat flux in the new phosphoric acid tower.