Optimal design of heat and water recovery system for petroleum refinery $CO_2$ reduction

Abstract

Petroleum refinery is one of the major $CO_2$ emitters in the global industrial sector. The refinery has a number of various $CO_2$ emission points including the utility plants and furnaces. Also, it consumes a large amount of industrial water as feedstock for utility. In particular, for those located in the Middle East area which is arid, the supply of the water resource turns out to be a serious problem, so it is highly demanded to utilize the water resource more efficiently. To overcome these challenges, the heat and water recovery system (HWRS) applied to the steam plant of the petroleum refinery is proposed. The system allows recovering heat energy of hot flue gas streams to heat the condensate water through heat exchangers. Moreover, the flue gas streams are further cooled below the water dew point to recover water. The goal of this study is to find optimal design of HWRS by solving an optimization problem with calculated flue gas data for reducing the refinery-wide $CO_2$ emissions and saving costs. The refinery-wide simulator is developed based on an actual refinery data to obtain flue gas data to be input value for the optimization problem. The mixed integer nonlinear programming (MINLP) problem is formulated and solved for the heat exchanger network (HEN) synthesis of the system. The potential for $CO_2$ reduction and cost saving are assessed with the optimal HEN configuration. In addition, sensitivity analysis is conducted by perturbing several economic parameters that affect the optimization results.