Research On CO₂ And H₂S Removal From Natural Gases And Antifoaming Performance Of UDS Solvent

In order to meet the increasingly stringent emissions regulations, it is required that the sour components such as CO2 and H2S are reduced to lower and lower level. It has been an urgent problem in current field of natural gas purification of China how to develop purification process and efficient solvent for meeting various requirements. In the consideration of the present problem, the UDS solvent with excellent efficiencies on removing sour components such as CO2 and H2S has been developed in this laboratory. In this paper, the performances of UDS solvent on removing CO2 as well as H2S from natural gas were studied and compared with those of MDEA. The antifoaming performance of UDS solvent was investigated and improved.Firstly, the kinetic performances of CO2 absorption into solutions of UDS-F were determined, under the conditions of temperature of 323K, UDS-F concentrations of 4.37 mol·L-1. The absorption rates of CO2 into UDS-F solutions N and the observed overall rate constant kobs were 6.82×10'6 kmol·m-2·s-1 and 7683.57 s-1 respectively, the absorption activation energy Ea were 44.92 kJ·mol-1. Under the similar absorption conditions, UDS-F showed greater N than MDEA. The results obtained from atomospheric absorption experiment indicated that UDS-F solvent showed good performances while purifying simulated oilfield associated gas. In the condition of temperature of 35℃, Vg/Vl of around 250, and mass fraction of 30%, the contents of H2S and CO2 in purified gas were lower than 2 ppm and lower than 20 ppm respectively, which reduced the possibility of hydrate formation in conveying process. The results of side-stream and industrial tests in Puguang Gas PurificationPlant indicated that UDS solvent showed excellent purification performances for high sour natural gas. As compared to MDEA, UDS solvent displayed the same H2S removal performance and higher CO2 removal performance. Furthermore, UDS solvent showed excellent antifoaming performance with adding of 20 ppm DF - E defoaming agent.