气体硫黄还原磷石膏制酸新工艺预还原数值模拟

Numerical simulation of pre-reduction for a new process of acid production from phosphogypsum by gas sulfur reduction

气体硫黄还原磷石膏制酸联产硫铝酸盐水泥熟料是处理工业固废磷石膏的新工艺技术,通过计算流体力学(CFD)与实验验证相结合的方法对该系统的还原炉进行研究分析,利用基于欧拉-拉格朗日的组分运输模型实现还原炉内气体硫黄和磷石膏生料颗粒的多相流化学反应过程的数值仿真计算,通过对数值仿真结果与中试试验数据的分析对比,得到了还原炉内温度、速度、组分、浓度场等关键工艺参数,且还原炉内气固相运动轨迹以及温度场分布均稳定。在入炉气体硫黄温度1023K、CaSO_(4)与气体硫黄的摩尔比为3.14∶1的条件下,CaSO_(4)预还原率达到26.84%,满足深度还原的要求。数值模拟关键显性工艺参数与中试系统运行数据吻合度高,误差仅为3.82%~4.84%,为气体硫黄还原磷石膏工艺技术的优化开发提供了数据支撑。

The gas sulfur reduction of phosphogypsum for acid co-production of sulfoaluminate cement clinker is a new process technology for treating industrial solid waste phosphogypsum.The reduction furnace of this system was studied and analyzed by combining computational fluid dynamics(CFD)and experimental validation,and the numerical simulation of the multiphase flow chemical reaction process of gas sulfur and phosphogypsum raw material particles in the reduction furnace was realized by using the Euler-Lagrange based component transport model.By comparing the numerical simulation results with the pilot test data,the key process parameters such as temperature,velocity,components and concentration fields in the reduction furnace were obtained,and the trajectory of gas-solid phase motion and temperature field distribution in the reduction furnace were stable.Under the condition that the inlet gas sulfur temperature was 1023K and the molar ratio of CaSO_(4) to gas sulfur was 3.14∶1,the pre-reduction rate of CaSO_(4) reached 26.84%,which met the requirement of deep reduction.The numerical simulation of key dominant process parameters agreed well with the pilot system operation data with an error of only 3.82%—4.84%,which provided data support for the optimization and development of gas sulfur reduction phosphogypsum process technology.