Performance Study Of Steel Slag As An Absorbent Based On Wet Flue Gas Desulfurization Technology

FGD technology is the most effective way to control SO₂ pollution in the world,and wet FGD technology by calcium-based absorbent is widely used.Calcium-based wet FGD technology uses CaCO₃ and CaO as the absorbent customarily;the product is gypsum,while China is rich in resources of gypsum.On the other hand,CaO is expensive as an absorbent. So finding a cheap and efficient absorbent makes a great sense both in reducing cost and in protecting environment.Steel slag contains a large amount of CaO and it is the industrial waste from the process of metallurgy,so it has a potential for an absorbent.In this research, steel slag is prepared as a new absorbent in the rotating-stream-tray scrubber to study its performance.The research is willing to develop a cheap,efficient and practical absorbent.At the same time,it opens up a new way to disposal the waste.Effects of some key operating parameters such as liquid/gas ratio(L/G),inlet SO₂ concentration(y₀) and inlet temperatures(T₀) on SO₂ removal efficiency had been studied to make a best condition for FGD process.Comparison and research are analyzed when steel slag is slurried with pure water and sea water based on the single factor experiment.In order to understand the mechanism of desulfurization from steel slag,in the experiment MgO, Fe₂O₃,Al₂O₃ and SiO₂ are slurried with CaO respectively,and their effects on SO₂ removal in steel slag are analyzed.The two from Fe₂O₃,Al₂O₃ and SiO₂ are slurried with CaO respectively,and their synergistic effects on SO₂ removal in steel slag are analyzed.And finally steel slag has been characterized before and after SO₂ capture.The results show that the SO₂ removal efficiency can reach above 85%under conditions as following:the concentration of the absorbent solution is 2%,the inlet temperature is 55℃, and liquid/gas ratio is above 4.85L/m³.Furthermore,MgO,Fe₂O₃,Al₂O₃ and SiO₂ have positive functions while Fe₂O₃+Al₂O₃ has a synergistic effect on the increase of SO₂ removal efficiency.The experiment results prove that steel slag is an effective absorbent for FGD process in rotating-stream-tray scrubber.