Current status of MHI’s CO2 recovery technology and optimization of CO2 recovery plant with a PC fired power plant

Abstract

It is the opinion of the authors that CO2 Capture and Storage (CCS) technology can significantly contribute as an effective countermeasure against climate change, allowing us to continue the utilization of fossil fuels for primary energy production. However for this technology to be widely deployed on a commercial basis there are three key issues that need to be addressed; (1) Reduction in energy consumption, (2) Efficient integration with other environmental control equipment of a PC power plant and (3) Reduction in the decrease of net electrical output. MHI has delivered multiple commercial CO2 recovery plants in the chemical and fertilizer industries, which recover CO2 from natural gas fired flue gas, with four commercial plants in operation and another four under construction, all utilizing the proprietary KM-CDR process. In order to gain experience with CO2 recovery from a coal fired flue gas stream, Mitsubishi Heavy Industries (MHI), together with a subsidy from RITE and cooperation from J-POWER, constructed a 10 metric ton per day (T/D) CO2 recovery demonstration plant at the 2×500 MW Matsushima power station in southern Japan. This demonstration plant has subsequently achieved more than 4,000 hours of successful test operation during 2006–2007 with a further 1,000 hours during 2008, and testing continues today. The demonstration testing confirmed that the KM-CDR process is applicable to coal fired flue gas streams. Future research priorities include the improved integration of the CO2 recovery process with the flue gas pre-treatment components and the additional optimization of removal and separation methods for coal based impurities accumulating in the absorbent. An issue of concern for power plant operators is the reduction of the net electrical output due to the demands of CO2 recovery process. MHI has made significant improvements in this area and in the efficiency of absorbents. However, it is necessary to further reduce the adverse impact on the net electrical output of the power plant via astute integration of the energy transferred between the power plant and the Post Combustion CO2 Capture (PCC) plant. MHI is investigating the following concepts; (1) Utilizing the waste heat of the PCC plant for the power plant, (2) Utilizing heat recovery from the flue gas for the CO2 recovery process and (3) Utilizing the compression heat of the CO2 compressor for the CO2 recovery process.