Patent ID: 9562717
Date: 2017-02-07
CPC Classifications: F25J

Claim:
1. A refrigeration process for cooling a product feed stream, the process comprising passing the product feed stream through a heat exchanger comprising a first refrigerant stream of mixed refrigerant and a second refrigerant stream of mixed refrigerant; wherein the first refrigerant stream is configured to evaporate at a temperature which is lower than that of the second refrigerant stream; and wherein the first refrigerant stream, upon exiting the heat exchanger, is subject to an initial compression prior to mixing with the second refrigerant feed stream from the heat exchanger to form a single refrigerant stream which is subjected to a second compression to form a compressed refrigerant stream, and wherein: (i) the compressed refrigerant stream is split into vapour and liquid phases in a flash unit, and a portion of the vapour phase from the flash unit is mixed with a portion of the liquid phase to form the first refrigerant stream and the remainder of the vapour phase is mixed with the remainder of the liquid phase to form the second refrigerant stream; and (ii) the first and second refrigerant streams are then subject to cooling in the heat exchanger followed by expansion prior to being reintroduced into the heat exchanger to cool the feed stream.