A heuristic approach to design a cost-effective and low-CO2 emission synthesis in a heat exchanger network with crude oil distillation units

Abstract

This paper presents a tradeoff grassroots design of cost-effective and low-CO2 emissions heat exchanger networks for crude oil distillation units (CDUs) to address high energy consumption in CDUs. To reduce the impact of the objective's magnitude on the optimization searching direction, a normalization process handling the objectives to the dimensionless indexes to assess the performance of CDU is presented. An originally designed random walk algorithm with compulsive evolution (RWCE) and a special superstructure nodes-based non-structural model (NNM) is adopted for the multi-objective optimization problem. The comparison analysis shows that the proposed model and the heuristic algorithm are robust in solving the global optimization problem. In addition, aiming to investigate the evolution mode of utilities in RWCE, an active evolution strategy of utilities (RWCE-AU) is proposed to promote structural evolution by altering the heat loads of utilities by a certain probability. Finally, several industrial CDU cases are optimized by RWCE and RWCE-AU in this work. The continuous improvement solutions have highlighted that the RWCE could yield a better optimal total annual cost (TAC) compared to the reported initial case. Moreover, the RWCE-AU enhances the searching ability of RWCE and provides a better tradeoff between the economic benefits and the environmental impacts.