| The promulgation of GB 39728-2020"Emission Standards for Air Pollutants in Onshore Oil and Gas Mining Industry"is an important step to implement the new development concept and achieve the goal of energy saving and emission reduction,and the promulgation of GB39728-2020 is a clear regulation on the management and emission of air pollutants from the national level.However,the SO2 mass concentration in the exhaust gas of a natural gas purification plant in southwest China is 3778mg/m3,which is much higher than the requirement of less than 400mg/m3 in the exhaust gas of natural gas purification plants with sulfur recovery scale greater than 200t/d in the latest version of the national standard to be implemented in 2023.In order to solve the problem of high SO2 concentration in the tail gas of this natural gas purification plant,an additional tail gas treatment process is needed to improve the sulfur recovery rate and reduce the SO2 concentration in the tail gas based on the existing sulfur recovery process.Based on this,this thesis takes the additional tail gas treatment process as the research object,establishes the sulfur recovery and tail gas treatment process calculation model,carries out the model adaptability analysis and process parameter optimization,recommends the best combination of process parameters applicable to this tail gas treatment process,and provides theoretical guidance for the field application of the tail gas treatment process.The main research results are as follows.（1）Based on the field tail gas treatment process,a sulfur recovery process model was built with the help of Pro Max and HYSYS software,and the model calibration was carried out using field data.The results show that the sulfur recovery rate of the revised model is 99.87%and the SO2 mass concentration in the exhaust gas is 394mg/m3,which meets the needs of exhaust gas treatment.On this basis,the model adaptability analysis was carried out by using response surface analysis,and the effects of acid gas treatment volume,acid gas composition,absorption tower inlet pressure and temperature on absorber circulation volume were discussed in detail,and the interaction law between H2S content,CO2 content and treatment volume and the influence law on absorber circulation volume were explored.（2）Based on SPSS software and Design-Exper software,the study on the influence of single and multiple factors on the purification effect of tail gas treatment process was carried out,and the significance of the influence of single and multiple factors was analyzed.125k Pa,the absorber circulation volume is not less than 40m3/h,the absorber concentration is not less than 30%,the number of plates is not less than 18,and the mass concentration of SO2 in the tail gas is less than 400mg/m3,the significance order of each influencing factor is obtained,and the function relationship between the mass concentration of SO2 in the tail gas and the process energy consumption is established respectively.（3）Based on RSM and BP neural network,the optimization of tail gas treatment process parameters was completed with the variable parameters of absorption tower inlet gas temperature,absorption tower inlet gas pressure,absorber circulation volume and absorption tower plate number,and the lowest energy consumption as the target,and the optimal combination of process parameters was determined as follows:absorption tower inlet gas temperature 30℃,inlet gas pressure 105.19k Pa,absorber circulation volume 39.68m3/h The optimal combination of process parameters was determined as follows:absorption tower inlet gas temperature 30℃,inlet gas pressure 105.19k Pa,absorber circulation volume 39.68m3/h,absorption tower plate number 18,SO2 mass concentration in tail gas 397.6mg/m3,energy consumption 13765.1k W,which provides theoretical guidance for the treatment of tail gas emission from this natural gas purification plant. |
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