Objective Aiming at the problems of using single device and low recovery rate for ethane recovery process to the rich raw gas at home, based on the former cold residue reflux process(CRR), two efficient ethane recovery processes, namely cold residue reflux process with flash evaporator(CRR-FE) and cold residue reflux process with feed subcooled(CRR-PS) are proposed in this paper.

Methods The simulation was improved by using HYSYS software under the condition that the ethane recovery rate was maitained higher than 95%. Three groups of progressively richer gas were set up to compare the CRR and the improved process with a comprehensive energy consumption and exergy analysis.

Results The improved process has good energy saving effect, among which the CRR-PS has obvious energy saving effect, and the CRR-PS saves 9.4% of the integrated energy consumption when the gallons per minute (GPM) is 4.3. The three processes have the highest yield loss for the external compressor in the main equipment compressor, followed by the demethanization tower and propane refrigeration in the tower equipment, and then the heat exchanger, air coolers, water coolers; the improved process has a very good performance, and the overall exergy efficiency is higher than 80%, and the size of the total exergy efficiency is in the order of CRR-PS > CRR-FE > CRR; When the GPM is 4.3, the CRR-PS exergy losses are 28 471 kW, which is 3.9% lower compared to the CRR, indicating that the CRR-PS has less exergy losses and has a good potential for energy savings.

Conclusions The CRR-PS is highly adaptable to rich gas and provides the better energy savings.