A novel approach for operational optimization of multi-stage refrigeration cycles in gas refineries

Abstract

The efficient use of energy in refrigeration cycles of gas liquefaction plants is a contemporary topic of interest. The previous optimization studies on refrigeration cycles have not considered the components' operational limitations. By considering the fact that in operating plants, all constraints must be thoroughly taken into account, this paper presents a novel approach for operational optimization of in-use refrigeration cycles which takes into account the operational limitations of the components as well as the interaction between the refrigeration cycle and the core process. This novel approach exploits a combination of thermodynamic principles and pinch technology to express the multi-stage refrigeration cycles' power consumption as a function of several independent variables. To examine the applicability of the proposed approach, it is used to optimize a three-stage refrigeration cycle in a propane liquefaction plant. About 15.4% reduction in the specific power consumption is achieved.