Design of mixed refrigerant cycle for low temperature processes using a thermodynamic approach

Minimizing the work consumed by a refrigeration system is an eective measure for reducing the cost of products in sub-ambient chemical processes, such as olen plants. A recent advancement has been the introduction of mixed working uids in refrigeration systems in place of pure working uids. Due to the lack of a systematic design method for the Mixed Refrigerant Cycle (MRC), conventional approaches are largely trial-and-error and, therefore, operations can be under far from optimal conditions. In this paper, a novel method for systematic design of MRCs is presented, which combines the benets of the thermodynamics approach and mathematical optimization. Based on the success of the proposed systematic method for the optimal selection of refrigerant composition and operating pressures, the method is extended to give optimal arrangement of the cycle components. The procedure is demonstrated using a case study of the design of MRC for a typical olen plant.