Acid Gas Phase Analysis And Ground Reinjection Process Research

Along with the development of Chinese economy,the acid gases such as H2S、CO2 which generated by the petroleum industry、coal chemical industry and natural gas fields are gradually increasing.The equipment、environment and personal safety are all threatened by these acid gases,so how to deal with these acid gases is the most important problem.China usually adopts sulfur recovery technology,that converts H2S into sulfur,CO2 and the SO2 which produced by the sulfur recovery technology are directly discharged,that is harmful to the environment.Due to the strict regulations,acid gas injection has become the environmentally friendly way to deal with the acid gas.The design of acid gas injection needs a thorough knowledge of the phase equilibrium of acid gas,so this paper firstly analyzes the equilibrium of acid gas.It points out that,the Peng-Robinson equation is good fit of the non-aqueous phase and the water content of hydrocarbons through comparing the experimental data and the calculation results for PR equation,but its accuracy of prediction is poor in the water content of acid gas.Through modifying binary interaction coefficients of H2S-H2O、CO2-H2O,the accuracy of prediction of water content of acid gas has improved.This paper proposes three schemes of acid gas injection based on the study of acid gas phase behavior,stablishes calculation model by the Hysys and the modified binary interaction.The results show that the injection recovery rates of H2S and CO2 in second schemes and the third schemes are 99.99%and 100%,and the economic cost of the third scheme is lower than that in second scheme.The TEG dehydration can be set after the third stage,the propane refrigerant can be set after the second stage or the third stage and the,and the last one is recommended because of the energy and effect.The investment of acid gas injection process is 63.9%of the sulfur recovery process without consideration of acid gas injection subsidies and sulfur product revenue,and it shows that the acid gas injection technology is feasible.