Thermodynamic and economic analysis of ethane recovery processes based on rich gas

Abstract A novel enhanced split heat-exchanging (ESH) process with self-refrigeration and absorber is proposed in this article. And a feed gas condition of a proposed ethane recovery plant in China is selected as basic data to simulate and analyze the recycle split vapor process with propane refrigeration (RSVP) and the ESH process. The results show: ① The ethane recovery rate of the RSVP and ESH processes can reach over 95%; ② The ESH process has obvious energy saving advantages compared with the RSVP process; ③ The ESH process has better heat integration in precooling cold box than the RSVP process. And the difference in the exergy destruction between the two processes is mainly reflected in the cold box LNG-101, the secondary compressor K-105 of the refrigeration system, and the residue gas compressor K-103; ④ The economic analysis results show that both processes have good economic benefits, while the ESH process has lower utility costs. From the perspective of internal rate of return and net present value, the ESH process is more economical than the RSVP process.