Sweetening Of Natural Gas With Sulfolane Activated Methyl Diethanolamine

The growing demands of natural gas led to the improvement of the existing sweetening processes for the well-being of public,energy and emission control.Changqing oilfield natural gas plant is situated in the northwestern part of China.The key equipment in the plant for the gas processing is the absorber and regenerator column,the design and processing scale of a single piece equipment is 375×10⁴m³/day.Though the absorber is using 40%(wt)MDEA in the process,but the concentration of H₂S in the processed natural gas still does not meet the requirements of GB-17820-2018.In this work,a study is carried out for H₂O-CO₂-sulfolane activated MDEA-H₂S is merged into the acid-gas-chemical solvents in Aspen HYSYS V9.The rigorous kinetic model is utilized to simulate and validate the plant.The results showed that 5%sulfolane activated 35%MDEA improved the absorption ability of H₂S(mg/m³)and CO₂(mol%)by 99.71%and 56.79%,respectively,and reduced the reboiler duty(MW)by 10.84%.Sensitivity analysis are carried out on the sulfolane activated MDEA solution concentration,circulation rates,temperature,reflux ratio,pressure and trays number of the absorber and regenerator column.With the increasing of activated MDEA concentration,it is observed that the absorber column efficiency decreased significantly.The study revealed that H₂S/CO₂absorption is improved by the activated lean MDEA solution circulation rates.H₂S/CO₂solubilities are considerably decreased with intensifying lean activated MDEA temperature.Sulfolane activated MDEA has a low mass loss compared to MDEA with temperature rising.It is identified that the growing number of trays in the absorber column decreases the concentrations of both H₂S and CO₂ in the sweet gas stream.Sulfolane activated MDEA reduced the absorber column internal temperature(oC).Increasing the regenerator column pressure maximized the temperature of the reboiler and hence reduce the reboiler duty.Regenerator column feed temperature effect both the reflux ratio and reboiler duty.Increasing the regenerator column feed temperature decreased the reflux ratio and reboiler duty.It is observed that increasing the regenerator column trays improved the H₂S/CO₂ desorption and good quality of clean activated MDEA is regenerated.