Study On The Process Of Sulfuric Acid Tail Gas Treatment By Ionic Liquid Method

In this paper,the desulfurization process of tail sulfate is studied.According to the actual situation,the technological design and equipment design of desulfurization device for tail sulfate are carried out according to the gas volume of 120000Nm³/H.In terms of process design,on the basis of the original one-to-one suction process,an ion-liquid recycling absorption process is used to use the chemical absorption characteristics of Ionic liquids to absorb SO₂ in tail gas at low temperatures,reduce the emission of sulfur dioxide in tail gas,and then desorption of SO₂ at high temperatures.More than 99% pure?dry?SO₂ gas is obtained for the production of liquid SO₂ and 98% concentrated sulfuric acid.In terms of equipment design,in order to improve the absorption and regeneration efficiency,equipment such as absorption tower,drying tower,liquid heat exchanger,poor liquid cooler were designed and selected,and control requirements were put forward for the main process operation conditions.During the trial operation period of the device,it was found that SO₂ in the exhaust gas desulfurization device was up to 30 g/Nm³ due to the low conversion efficiency of SO₂ during the driving process of the sulfuric acid device.Due to the dissolution of SO₂ in the circulating liquid,the p H of the circulating liquid rapidly decreased.At p H below 4.0 and temperature above 100?,there is a SO32-dismutation reaction to produce a elemental sulfur blockage device.The optimization and control measures are put forward for the problem of exposure during the test run of the device.The following conclusions are obtained: The first is to optimize the process flow,control the residence time of circulating liquid in the regeneration tower less than 20 minutes,and the p H ?4 to inhibit the disproportionation reaction of SO32-in the circulating liquid;the second is that the device can operate steadily,the sulfur dioxide emission concentration in the tail gas is less than 300 mg/Nm³,which is lower than the national emission standard of 400 mg/Nm³.After adding the static demister,the acid mist will be reduced from 30 mg/Nm³ to 5 mg/Nm³;the third is to increase the freezing desalti After that,the problem of crystallization blockage of sodium salt has been solved.Fourthly,ionic liquid desulfurization process is an environmental protection process,and no other waste and by-products are produced in the process of production and operation.