Low Sulfur Content, High Carbon Sulfur Ratio, Natural Gas Desulfurization And Decarbonization Process

The purification of low sulphur and high ratio of carbon to sulfur to natural gas is different from the previous process of sour natural gas,so the development and utilization are still in its starting stage in our country. Through building model of the MDEA absorber, several affecting actors are analyzed. This paper targets at the characteristics of low sulphur and high ratio of carbon to sulfur to natural gas, to determine to use MDEA, MDEA+DEA as desulfurization and decarbonization solvent, and analyzes and studies technology parameters and energy consumption of the desulfurization and decarburization process.This paper maks simulation study on the performance of three kinds of MDEA solution activator including EA, DEA and PZ. Under the same renewable energy consumption, the regeneration effect of lean amine liquid is in the order:DEA> PZ> MEA, under same solvent circulation amount, CO2 purifying degree is in the relation that PZ> MEA> DEA. For comprehensive consideration, when CO2 is more than 5%, desulfurization decarburization of low sulphur and high ratio of carbon to sulfur to natural gas chooses MDEA/DEA mixed amine as absorption solvent, when CO2 is less than 5%, low sulphur and high ratio of carbon to sulfur to natural gas uses MDEA solution as absorption solvent.Purification technology case of typical low sulphur and high ratio of carbon to sulfur to natural gas is simulated and simulation results show that the appropriate proportion of MDEA solution:DEA is determined that is H2O=40%:5%:55%(mass ratio). According to the solution formula, the key analysis and discusses are done on the main technological parameters affecting desulfurization and decarburization process, and the reasonable process parameters are obtained:temperature of feed gas into the tower is 25?, the absorption pressure is 4.5 MPa, regeneration temperature is 121?, the temperature of barren fluid into the absorption tower is 42?, absorption tower plate number is 20. Gas purification quality can satisfy the demands of GB 17820-2012.Energy consumption of MDEA/DEA method desulfurization decarburization process on low sulphur and high ratio of carbon to sulfur to natural gas is studied to determine the influence on performance by processing conditions like content of feed gas, absorption tower pressure, CO2 and H2S content in feed gas. Through the response surface method, Quadratic regression relationship is established among H2S content in the feed gas, CO2 content in the feed gas and temperature variable of barren solution into the tower and the flow rate of equired barren solution and required energy consumption. Application of response surface analysis method is used to analyze interaction function of multiple factor, interaction relationship of the various factors is:interaction between flow rate of feed gas and CO2 content in feed gas> nteraction between flow rate of feed gas and H2S content of feed gas> interaction between CO2 content in feed gas and barren solution temperature> interaction between H2S content in feed gas and barren solution temperature.