Integrating O-2 production with power systems to capture CO2

Chemical cycles for separating oxygen (O-2) from air were developed many years ago. These cycles involve a chemical reaction to capture O-2 from the air and a change in the operating conditions to effect a controlled breakdown of the newly formed product to release the O-2 and regenerate the original species. These cycles are generally more expensive than cryogenic separation of air, partly because they consume high-temperature thermal energy (500-850 degrees C). The chemical cycles can be integrated with high-temperature power cycles to provide efficient heat cascading and recovery because the different temperature levels at which they require thermal energy are compatible with the levels encountered in high-temperature power cycles. The O-2 can be used in the combustion process to generate a CO2-rich stream that is more readily separable for production of commercial-grade CO2. This paper presents a preliminary discussion of such integrated systems to facilitate the capture of CO2, aimed at reviving interest in these cycles. (C) 1997 Elsevier Science Ltd.