Study On Natural Gas Purification And Acid Gas Treatment Process Of High Carbon And Sulfur Ratio

This paper is aimed at dealing with the handing method of high carbon-sulfur ratio natural gas. Analyzing the characters of this kind of natural gas, the suitable purification process is presented, including MDEA/DEA desulfurization and decarbonization process and TEG dehydration process. The sulfur treatment options of sulfuric acid gas with low sulfur concentration were discussed, such as direct incineration, Claus process and direct oxidation method.The Aspen HYSYS is conducted to simulate the purification process of high carbon-sulfur ratio natural gas, and the simulation results show that:the optimal operating conditions are DEA molar ratio of3.5%, circulating ratio of100m3/h, absorption column stage of16, and the operating pressure of5000kPa; for TEG dehydration process, the favorable TEG mass concentration of99%, and the dew point of the purified gas is-11℃. The H2S content in dry gas is13.42mg/m3, and the concentration of CO2in dry gas is2.97%, and the production of dry gas is192.888×104Nm3/d. The quality of the dry gas is satisfied the second standard of GB17820-2012. The concentration of H2S in sour gas is8791.6mg/m3, with94.66%of CO2, and the flow rate of sour gas is6.9624x104Nm3/d.The results of three kinds of sulfur treatment strategies of sulfuric acid gas of high carbon-sulfur ratio are shown as follows:The SO2content of the off-gas generated from burning directly of acid gas is lower than the second standard of GB16297-1996, so the off-gas is suitable for direct emissions, and the hight of the exhaust funnel is set to60m; Because the H2S content of acid gas is less than5%, so using the Claus process must provide a concentrated acid gas H2S, MDEA amine using an acid gas absorbent concentration of H2S provides poor results; the sour gas through the process of ferric oxide process can simply let into the atmosphere after incineration.