Study And Application Of Ammonia Absorption Of Sulfuric Acid Tail Gas

In this paper,the sulphuric acid tail gas produced in the production of sulfuric acid from pyrite is taken as the research object.The tail gas of sulfuric acid contains sulfur dioxide,sulfur trioxide?acid mist?and a little nitrogen,and the sulfur dioxide and sulfur trioxide in the tail gas are corrosive.The temperature produced by the solution in water has higher requirements on the equipment,and the tail gas of sulfuric acid has a great pollution on the air.It synthesizes the specific characteristics of our products?sulfuric acid,ammonium phosphate,synthetic ammonia,sodium nitrite and sodium nitrate?.The SO2 and acid mist produced by the secondary washing of dilute ammonia water produced by the ammonia production line were put forward to reduce the characteristic pollutants in the tail gas.After the decomposition of concentrated sulfuric acid,the main product of ammonium sulfite,the sulfur dioxide gas returned to the conversion stage and continued to be converted to produce concentrated sulfuric acid,and the 35% ammonia sulphate liquid was sent to the phosphoric acid workshop as the nitrogen nutrient of monoammonium phosphate.Because of the high decomposition rate of ammonium sulfite by using concentrated sulfuric acid as acid hydrolyzer,the absorption equilibrium is achieved in the cycle.In view of the chemical and physical properties of the substances produced after the absorption of sulfuric acid tail gas,the large equipment made of FRP was used as the main equipment to prevent the damage caused by the corrosion of the product ammonium sulfate and the temperature to the equipment,and to prolong the maintenance time of the equipment.From many aspects,such as plane layout and elevation arrangement,etc.Consider,as small an area as possible,easy to operate and monitor.Before the revamping,our company has 150000 tons / year and 200000 tons / year pyrite acid plant,350000 ton / year pyrite acid plant tail gas acid fog?SO3?is 33 mg / m ³so₂ total emission total 474.2 t / a so₃ emission total 28.6t/a:The consumption of 350000 tons of pyrite sulphuric acid production tail gas absorption unit is 15% ammonia water 1066.4 tons / a and 35% ammonium sulfate 1780.8 tons / a.On the basis of the secondary washing tail gas,the equipment added one more process water to clean and adjust the sulfur dioxide and acid mist in the sulfuric acid tail gas thoroughly.The large FRP equipment is used to reduce the excessive volume of the equipment caused by temperature and corrosion,and the spray system is used to increase the contact surface between exhaust gas and detergent,to accelerate the washing efficiency and to reduce the washing time.The equipment covers a small area,the process is relatively simple and easy to master,the advanced instruments and monitoring equipment are adopted,the DCS system is simple and clear,easy to monitor and operate,and greatly reduces the labor intensity and labor level of the operators.The successful implementation of the project has saved the utilization of ammonia water by product of synthetic ammonia,reduced the damage of dilute ammonia water to the environment,and played a good social,economic and environmental benefit to the discharge of sulfuric acid tail gas to the standard.