流化催化裂化烟气SO_(3) 形成转化规律及排放特性研究

Study on Formation,Transformation and Emission Characteristics of SO_(3)in FCC Flue Gas

SO_(3)是造成流化催化裂化湿法脱硫烟气蓝色烟羽现象和后部设备腐蚀堵塞的主要原因。采用改进的异丙醇吸收法,研究分析了SO_(3)在两套催化裂化装置再生器、SCR(选择性催化还原法)脱硝反应器和湿法烟气脱硫装置的生成转化规律。研究结果表明:从再生器到脱硫塔出口,除经过SCR反应器后SO_(3)浓度略有升高外,SO_(3)浓度不断降低;SCR脱硝催化剂在一定程度上促进了SO_(2)向SO_(3)转化,使得SO_(3)浓度小幅上升,而SO_(2)浓度略有下降;两套装置湿法脱硫对SO_(3)的脱除率分别为69.4%和85.2%。硫转移剂能有效促进烟气中的硫向干气和液化石油气中转移,明显降低烟气中SO_(3)浓度,但难以彻底消除烟气蓝色烟羽现象。

SO_(3)is the main reason for the blue plume of flue gas from wet desulfurization process in FCC unit;besides,it leads to the corrosion and blockage of the equipment.The formation and transformation of SO_(3)in regenerators,SCR reactors and wet flue gas desulfurization devices of two FCC units were studied by using improved isopropanol absorption method.The results showed the concentration of SO_(3)decreased continuously from the regenerator to the outlet of the desulfurization tower,except for a slight rise through the SCR reactor;SCR catalyst promoted the conversion of SO_(2)to SO_(3)to a certain extent,which made the concentration of SO_(3)increase slightly,but that of SO_(2)decrease slightly;The removal rates of SO_(3)in the two units were 69.4%and 85.2%,respectively.In addition,the effect of sulfur transfer agent on sulfur conversion and SO_(3)removal was studied.It indicated the agent can effectively promote sulfur transfer from flue gas to dry gas and liquefied gas,as well as significantly reduce SO_(3)concentration in flue gas,but it was difficult to completely eliminate blue plume of flue gas.