Optimizing ethane recovery in turboexpander processes

Optimization of ethane recovery using the CRR process shows that, except for the case of lean gas at low demethanizer pressure, the CRR process reduces to GSP, in which there is no reflux stream and therefore no added cryogenic compression and heat exchange equipment. Adding a second cold separator, operating at lower temperature, in GSP is found to lead to more or less recovery depending on the NGL content of the feed gas and the demethanizer pressure. GSP is also compared with the conventional turboexpander process. Optimization shows that adding more equipment or even flow splitting may lead to less ethane recovery.