Advanced exergy analysis of novel flash based Helium recovery from natural gas processes

Two cryogenic Helium recovery processes which are based on the flash separation are investigated and analyzed. The presence of Helium in the natural gas affects shape of its phase envelope. Effect of various components concentration on the natural gas phase envelope shape is investigated. Two modified cryogenic flash based processes are introduced. Two new parameters are proposed in order to evaluate performance of the under consideration processes. Modified processes are investigated by the exergy analysis method. Exergy loss and exergy efficiency of the process components are calculated. Results show that the compressors have the lowest exergy loss in both processes. In the compressors high portion of exergy destruction is related to the avoidable part that means this exergy destruction can be decreased. But in the multi stream heat exchangers high portion of exergy destruction is related to the unavoidable exergy destruction. Endogenous/exogenous destructions shows that portion of endogenous exergy destruction in the components is higher than the exogenous part. In fact interactions among the components do not affect the inefficiencies significantly.