循环镁法烟气脱硫产物MgSO_3的热解回用工艺研究

Study of Pyrolysis and Recycling of MgSO_3 in FGD Process by Magnesia

通过类似于固定床的热解实验,研究了循环镁法烟气脱硫产物亚硫酸镁的最佳热解工艺条件。在确定可能的影响因素后,通过控制变量法,以二氧化硫产生率、亚硫酸镁分解率、产物活性为判定标准,优化各个控制因素后,得到了亚硫酸镁的最佳热解工艺条件为:热解温度550℃,升温速率10K/min,并且在热解前须对亚硫酸镁进行充分干燥。经测定,该条件下热解样品中二氧化硫产生率达到92%,亚硫酸镁分解率接近80%,热解后的氧化镁纯度为43.5%,并具有较高的反应活性,可作为脱硫剂回用。由于惰性物质的存在,实际脱硫副产物的热解效果略逊于亚硫酸镁样品,应努力控制其中惰性物质的含量。

This paper studies the best pyrolysis conditions in the recovery process of magnesium sulphites by fixed-bed pyrolysis experiments. An optimal control is taken to get the highest producing peneent of sulfur dioxide, magnesia yield and magnesia activity after confirming the likely impact factors. The optimal reaction condition is as listed, 550℃ as the pyrolysis temperature, lOK/min as the heating rate and drying magnesium sulphites before pyrolysis. Under this optimal condition, the producing pencent of sulfur dioxide is up to 92%, the decomposition rate of magnesium sulfite is near 80%, the purity of magnesia is 43.5% and its reaction activity is also superior. It can be reused as a desulfurizer. Because of the existence of inertia products, the pyrolysis effect of the real FGD byproducts is slightly inferior to magnesium sulphites, the content of inertia products should be strively controlled.