Optimization of flash-separation based CO2 purification units

Several CO2 capture and storage technologies, such as oxycombustion systems, membranes, pressure/temperature swing adsorption systems separate a stream of CO2 which does not meet the tight composition specifications required by the storage site. Thus, the captured CO2 must be processed by a CO2 purification unit (CPU). This paper will focus on flash separation-based CPUs where the partial liquification of the pressurized feed gas takes place by temperature reduction at constant pressure. In this paper two schemes of the CPUs are considered, one is a conventional flash separation-based CPUs and the other is a novel design with increased recovery of the CPU. The specific cost (€/tonCO2) of these CPUs has been optimized for different levels of carbon tax and captured CO2 purity using SCR, a recently published surrogate-based global-search algorithm.