Air Separation Technologies: Thermodynamic, Technical and Economical Aspects in Power Plants

The present study is centered around the problem of carbon dioxide capture and storage considered as an option to mitigate climate changes. In particular, the paper describes the oxy-fuel combustion, based on the ASU technology, applied to two different power plants with CO2 capture: a supercritical steam power plant fed with pulverized coal and a combined cycle power plant fed with natural gas. The paper analyses these two different technologies considering thermodynamic, technical and economical aspects. But if capital and operating costs cannot be overlooked, it is also necessary to estimate the energy required to operate an air separation plant. From this point of view the paper illustrates the main air separation technologies, reporting both cryogenic (ASU – Air Separation Unit) and non-cryogenic systems.