Research On Simulation Optimization Of Concentrated Sulfuric Acid Acetylene Purification And Recycling Waste Sulfuric Acid

Polyvinyl chloride?PVC?is one of the world's five largest thermoplastic general plastics,widely used in industry,agriculture,construction,power communications,medicine and other fields.Acetylene is an important raw material of calcium carbide acetylene method in the production of PVC,which purity determines the quality of PVC products.This paper analyzes the problems existing in the process of concentrated sulfuric acid acetylene purification and acetylene pressure swing adsorption?PSA?in the chlor alkali for the goal of high efficiency and green production.For the annual production capacity of 125 thousand tons of refined acetylene gas plant,to solve those issues above,this paper uses the chemical process flow simulation software to get the optimum process operating parameters in concentrated sulfuric acid clean acetylene section and the PSA of acetylene section.In order to solve the difficult problem of waste sulfuric acid treatment,this paper puts forward the method that the carbide slag neutralizes the waste sulfuric acid.Through the above methods,to achieve chlor-alkali enterprises green production and sustainable development.The VLE data of H₂S-H₂O system is reliable by the results of the thermodynamic consistency test.Then the binary interaction parameters of the ELECNRTL thermodynamic model and the Herry coefficients of C₂H₂ and H₂S were fitted and regression.And according to the comparison of calculated value and actual production data,the ELECNRTL model can simulate acetylene cleaning process accurately.To simulate and optimize the concentrated sulfuric acid acetylene cleaning process,single factor method was used to get the best operational parameters,including operating pressure,theoretical stage,operating temperature,absorbent flow rate and circulation flow rate.After optimizing,the flow rate of concentrated sulfuric acid decreased from 992 kg·h-1 to 700 kg·h-1,and the concentrated sulfuric acid saving was 29.44%;the flow rate of lye decreased from 800 kg·h-1 to 700 kg·h-1,and the lye saving was 12.50%;the flow rate of cooling water decreased from 9400 kg·h-1 to 1000 kg·h-1,and the cooling water saving was 89.36%.Through the optimization and modification,the total saving raw materials cost was 1.467 million·a-1,and an acetylene gas with mass fraction of 99.54%was obtained.In order to further purifying refined acetylene gas,this paper simulates and analyzes the PSA of acetylene by Aspen Adsorption.By analyzing the molecular sieve particle size,operating pressure of adsorption,bed height and feed flow rate parameters in PSA,the suitable parameters were determined and the adsorption time was prolonged.The operation process was changed from the original 5-tower PSA process to the 3-tower PSA process.After optimizing,the mass fraction of acetylene gas reached 99.99%,and the capacity of treating acetylene gas was expanded to 1.4 times,and the molecular sieve life was extended.To solve the difficult problem of waste sulfuric acid produced in the acetylene cleaning section,combined with the existing raw material-carbide slag,the scheme of using the carbide slag to neutralize the waste sulfuric acid was put forward and studied.Through the process,5953.6t·a-1 of the waste sulfuric acid and 4824t·a-1 of the carbide slag were disposed.At the same time,gypsum and sulfur brings economic and environmental benefits to the enterprise.