活性半焦在喷动床内脱硫过程的数值模拟

Numerical simulation of desulfurization in a spouted bed using activated semi-coke particles

提出将炭法烟气脱硫工艺结合喷动床技术来脱除烟气中的SO2,以达到节能减排的目标.以气固两相流体动力学为基础,采用欧拉双流体模型及颗粒动力学理论,引入修正的非均相脱硫动力学模型,对喷动床应用活性半焦颗粒脱硫的过程进行模拟.获得了喷动床具有喷射区、环隙区和喷泉区的流动状态及床内SO2浓度的分布情况.通过对不同工况下模拟结果的分析比较,表明了喷动床环隙区内脱硫效果最好,得出了反应温度和烟气的含氧量及湿度对脱硫效率的影响规律,其中烟气中湿度提高4%,脱硫效率大约提高20%.说明了在实际工程中,适当提高反应温度和烟气中O2与蒸汽的含量有利于提高活性半焦的脱硫效率.

For energy conservation and emission reduction,a spouted bed reactor using activated semi-coke particles to remove SO2 from flue gases was studied.The behavior of a gas-solid flow in the spouted bed was simulated by using the Euler-Euler two-fluid modeling approach,incorporating a kinetic-frictional constitutive model for dense assemblies of the particles.The developed model of a heterogeneous reaction considering the effect of the concentration of activated semi-coke was also used to predict the rate of desulfurization in the spouted bed.The distribution of SO2 and overall flow patterns including a stable spout region,a fountain region,and an annular down comer region within the spouted bed were obtained well.Then,the simulation results of different operating conditions were compared.The results show that the rate of desulfurization in the annular region is much higher,and the temperature of reaction along with the concentrations of O2 and H2O in flue gases have a prominent effect on efficiency of desulfurization.The humidity in the flue gas was increased by 4% and the efficiency of desulfurization was increased by 20% or so.Such research verifies that the efficiency of desulfurization in the spouted bed will be enhanced by proper elevation of the reacting temperature,the concentrations of O2,and humidity in flue gases.