OXYGEN PRODUCTION TECHNOLOGIES FOR OXY

Abstract

Carbon dioxide, a dominating contributor to global warming is emitted to the atmosphere from power plantsduring combustion of coal. Oxy-fuel combustion is a new technology leading to a simplified sequestrationof CO2. In this technology, fossil fuel is combusted with oxygen (instead of air) in such a way that the fluegas primarily consists of CO2, which can then be sequestered without significant processing. Part of the fluegas is used to dilute the oxygen in order to maintain the temperatures in the combustion process. The mainenergy penalty in oxy-fuel combustion is the cost of oxygen production. There are three major processes forair separation to produce oxygen, these are: cryogenic distillation, membrane separation and gas adsorption.Cryogenic distillation is well established process for large scale production but high energy consumption isthe main disadvantage of this process. Membrane and adsorption processes are common for small and mediumscale production. In gas adsorption, there are air separation techniques such as pressure and temperatureswing methods. The production of oxygen with 90-95% purity and 5000+tpd production is the main challengefor this technology. At present the technology that can supply oxygen in large quantity is the cryogenicseparation of oxygen from air. The papers aims at presenting a comprehensive review of the air separationtechnologies and identify areas that need attention so that oxy-firing can be achieved. The paper thereforelooks at different technologies used for oxygen production, economic concepts as well as integration issues inthe existing plants.