| Natural gas with H2S can be used as a clean energy after being purified. The sour gas the process of alkanolamine desulfurization also needs to be treated so that the exhaust gas can be discharged to meet the requirements of environmental protection, and sulfur recovery is a good way to deal with sour gas. The process of direct oxidation process has gradually attracted people's attention because the Claus process can not be used for low concentration H2S acid gas.The acid gas can not use the traditional Claus method whose content of H2S in acid gas of a purification plant in CNPC is very low (1.3%-4.5%), which belongs to a very poor acid gas. The plant used Clinsulf-DO sulfur recovery process for sulfur recovery according to the temperament characteristic of acid gas in the purification plant, but it can not meet the national requirements of environmental protection because of the low sulfur recovery rate and high concentrations of SO2 emissions in the running process., this paper put forward three kinds of process combined with the temperament characteristics of acid gas in the plant to solve this problem:to retain the original Clinsulf-DO process, and the old equipment was improved by using existing technology and mature process to improve the sulfur recovery rate and meet the emission concentration standard of SO2 in the exhaust;to replace the original process with a completely new technology of Selectox direct oxidation process; to change the original process into a complex iron oxidation process, that is, LO-CAT process in order to improve the sulfur recovery rate and meet the emission concentration standard of SO2 in the exhaust.In this paper, process simulation software is used to simulate the Clinsulf-DO process and Selectox process, and the calculation of LO-CAT process is carried out. Then, the results of the three were compared and analyzed. Finally, the Clinsulf-DO process was determined to carry out. The influencing factors analysis of the process is carried out in the paper according to the problems existing in the process of Clinsulf-DO, including the influence of preheating temperature, reaction temperature, H2S/O2 ratio, concentration of H2S, CO2 concentration and catalyst on the process. Then, the main equipment of the process equipment is simulated and analyzed, such as the temperature distribution of the adiabatic section, the data and the arrangement of the cooling pipe of isothermal section. The technology of Clinsulf-DO is improved on this basis from two aspects in the paper, the first purpose is to improve the conversion rate of H2S and try our best to reduce the content of SO2 in the tail gas, the reactor is improved to ensure that the temperature in the adiabatic section is not over-temperature, isothermal temperature is uniformity to enhance the H2S conversion rate; the second purpose is to reduce the content of SO2 in the tail gas, improve the sulfur recovery rate. The process is improved by using a physical solvent to absorb H2S and SO2 in the tail gas, and recycled to the reactor, and oxidation reaction is carried out to obtain elemental sulfur. Sulfur yield of improved process is increased from 94.47% to 99.11%. Sulfur recovery rate has been significantly improved, SO2 emission concentration is reduced from 5489mg/m3 to 139.4mg/m3 which is meeting the national emission requirements. |
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