Energy balance and sizing of refrigeration cascade system of 4 stages of applied to liquefaction of petrochemical inputs using carbon dioxide (CO2) in one of stages

Abstract

This article aims to demonstrate a computer simulation that describes the operation of a system geared to liquefaction of inputs processed in the petrochemical industry through a cooling system that operates in cascade with one of the cryogenic circuits loaded with carbon dioxide (CO2) The idea of carrying one of the cryogenic circuits with CO 2 was motivated by the large potential availability of this gas in Brazil in the coming years, due to the discovery of large oil reserves located in the pre-salt layer. In this layer, CO 2 is combined with natural gas, also quite abundant, which led us to choose the gas itself for the liquefying process. The concept of energy balance in thermodynamic cycles was adopted, applying the 1st Law of Thermodynamics for Control Volumes to obtain performance results that can meet the operating conditions imposed and enable the operation of the equipment modeled in this article. The modeling and dimensioning of the system were made by using the software EES (Engineering Equation Solver), while the COP circuit was emphasized for evaluation of the system performance emphasize.