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    January, 2009

CO₂ Capture and Development of an Advanced Pilot-Scale Cryogenic Separation and Compression Unit

Kourosh E. Zanganeh, Ahmed Shafeen, Carlos Salvador

At present, the use of fossil fuels in the current energy mix represents the largest source of CO₂ emissions, and important greenhouse gas, which is largely blamed for global warming. It is estimated that roughly 26 to 30 percent of all CO₂ emissions due to human activities come from fossil fuels used for generating electricity. Moreover, a variety of other industrial processes such as oil refineries, fertiliser and cement plants also emit large amounts of CO₂. The oppurtunity therefore exists for a significant reduction of CO₂ from industrial processes and power plants through CO₂ Capture and Storage (CCS). Currently, there are three main pathways to capturing CO₂ from fossil fuel energy conversion processes, namely, pre-combustion capture, post-combustion capture, and oxy-fuel combustion with CO₂ capture. Among these approaches, pre-combustion and oxy-fuel combustion take advantage of the fact that CO₂ capture is further facilitated by increasing the concentration of CO₂ in the flue gas stream, or by increasing the flue gas pressure, or both.

There are several different processes available for CO₂ capture and compression from low-pressure flue gas streams rich in CO₂. These processes vary from simple straight or once through low-temperature separation and compression to more comples processes involving some form of recycle and/or auto-refrigeration. Given the economic constraints often placed on the cost of CO₂ capture, and based on energy demand of each process, the ultimate success of these processes hinges on further refining the existing ones or developing new processes that can lower the cost of CO₂ capture. The CANMET Energy Technology Centre in Ottawa is currently pursuing a leading research and development programme in the field of near-zero emission fossil fuel technologies. This programme includes the development of next generation oxy-fuel combustion technologies, as well as the design and development of efficient CO₂ capture and compression processes to recover CO₂ from oxy-fuel and other fossil fuel energy conversion systems. In this paper, we present and discuss the technical challenges, development stages and commissioning of the CANMET's pilot-scale CO₂ capture and compression unit (CO₂CCU). This pilot-scale CO₂ separation and compression unit provides an excellent test platform to study the impact of flue gas impurities on the CO₂ capture process. This advanced gas separation system is first-of-a-kind pilot-scale unit that represents and integrated approach to oxy-fuel combustion of coal and other fossil fuels with CO₂ capture for storage.

© 2008 Elsevier Ltd. All rights reserved

Keywords: Greenhouse Gas Emission, CO₂ Capture, Low-temperature Gas Separation, CO₂CCU.

Source: Greenhouse Gas Control Technologies (GHGT) conference, 16-20 November 2008

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