Design and Analysis of Novel Co2 Conditioning Processes in the 3d Project

Abstract

In this work, CO2 conditioning processes for ship-based CCS chain are modelled using simulation software APSEN HYSYS. The case study uses the captured CO2 gas from the 3D project as the feed. The feed gas is saturated with water and contains H2S and CO as impurities. The purification processes for dehydration, desulfurization and CO removal are reviewed. Two liquefaction approaches, open cycle liquefaction and closed cycle liquefaction, are modelled and compared for transport pressure 7 bar and 15 bar. It is found that the energy requirement of the open cycle liquefaction process is higher than that of the closed cycle liquefaction process. For the closed cycle liquefaction, two refrigerants: ammonia and propane are considered. Results show that the energy requirement of the process using ammonia is lower than the process using propane. When comparing the two transport pressures it is found that liquefaction at 15 bar requires less energy than 7 bar. On top of that, both refrigerants are unsuited for the liquefaction of CO2 at 7 bar as their operating pressures are below 1 atm. Several optimization methods are tested on the closed cycle liquefaction design. The net power consumption of the closes cycle liquefaction is reduced after utilizing intermediate pressure ammonia cold from CO stripper for pre-cooling.