Synthesis and optimization of multilevel refrigeration systems using generalized disjunctive programming

•This paper presents a novel approach to develop a complete GDP model for the synthesis and optimization of multilevel refrigeration systems.•The model is based on simple model equations and developed to optimize the total shaft work requirement of the system.•The model is solved using the Logic-based branch and bound algorithm without explicit conversion to an MINLP problem.•A case study of the precooling cycle of the propane pre-cooled mixed refrigerant (C3MR) LNG process is used to test the model.•The model results are validated by simulation using Aspen Hysys software.•Shaft work savings of up to 11.1% and 12.3% are obtained for model results and simulated cases respectively against the base case. Preliminary estimations show that cost savings of up to 2.55 MM$/yr are realizable against the base case.