(1) It is becoming increasingly evident that the prolonged utilization of fossil fuels for primary energy production, especially coal which is relatively cheap and abundant, is inevitable and that Carbon Capture and Storage (CCS) technology can significantly reduce CO2 emissions from this sector thus allowing the continued environmentally sustainable use of this important energy commodity on a global basis. (2) MHI has co-developed the Kansai Mitsubishi Carbon Dioxide Recovery Process (KM-CDR Process (TM)) and KS-1 (TM) absorbent, which has been deployed in seven CO2 capture plants, now under commercial operation operating at a CO2 capture capacity of 450 metric tons per day (tpd). In addition, a further two commercial plants are now under construction all of which capture CO2 from natural gas fired flue gas boilers and steam reformers. Accordingly this technology is now available for commercial scale CO2 capture for gas boiler and gas turbine application. (3) However before offering commercial CO2 capture plants for coal fired flue gas application, it is necessary to verify the influence of, and develop countermeasures for, related impurities contained in coal fired flue gas. This includes the influence on both the absorbent and the entire system of the CO2 capture plant to achieve high operational reliability and minimize maintenance requirements. (4) Preventing the accumulation of impurities, especially the build up of dust, is very important when treating coal fired flue gas and MHI has undertaken significant work to understand the impact of impurities in order to achieve reliable and stable operating conditions and to efficiently optimize integration between the CO2 capture plant, the coal fired power plant and the flue gas clean up equipment. (5) To achieve this purpose, MHI constructed a 10 tpd CO2 capture demonstration plant at the Matsushima 1,000MW Power Station and confirmed successful, long term demonstration following similar to 5,000 hours of operation in 2006-07 with 50% financial support by RITE, as a joint program to promote technological development with the private sector, and cooperation from J-POWER. (6) Following successful demonstration testing at Matsushima, additional testing was undertaken in 2008 to examine the impact of entrainment of higher levels of flue gas impurities (primarily SOx and dust by bypassing the existing FGD) and to determine which components of the CO2 recovery process are responsible for the removal of these impurities. Following an additional 1,000 demonstration hours, results indicated stable operational performance in relation to the following impurities; 1) SO2: even at higher SO2 concentrations were almost completely removed from the flue gas before entering the CO2 absorber. 2) Dust: the accumulation of dust in the absorbent was higher, leading to an advanced understanding of the behavior of dust in the CO2 capture plant and the dust removal efficiency of each component within the CO2 recovery system. The data obtained is useful for the design of large-scale units and confirms the operating robustness of the CO2 capture plant accounting for wide fluctuations in impurity concentrations. (7) This important coal fired flue gas testing showed categorically that minimizing the accumulation of large concentrations of impurities, and to suppress dust concentrations below a prescribed level, is important to achieve long-term stable operation and to minimize maintenance work for the CO2 capture plant. To comply with the above requirement, various countermeasures have been developed which include the optimization of the impurity removal technology, flue gas pre treatment and improved optimization with the flue gas desulfurization facility. (8) In case of a commercial scale CO2 capture plant applied for coal fired flue gas, its respective size will be several thousand tpd which represents a considerable scale-up from the 10 tpd demonstration plant. In order to ensure the operational reliability and to accurately confirm the influence and the behavior of the impurities in coal fired flue gas, it is necessary to gain further operational experience with coal fired flue gas at large scale. To this extent, MHI has partnered with Southern Company and the Electric Power Research Institute (EPRI) in the United States for a large scale CCS demonstration project using the KM-CDR Process (TM) and KS-1 (TM) absorbent. MHI's coal fired CO2 capture experience and know how at 10 tpd scale aided in the design of the 500 tpd CO2 capture demonstration plant to be deployed at Plant Barry Power Station in Alabama. Commissioning of the plant will take place in Q2 2011 and an extensive test program is planned. Following successful demonstration of this plant, in relation to the effect of scale-up concerning the behavior of impurities, it is envisaged that larger-scale commercial CO2 capture plants can be designed and deployed for the coal fired power sector. (9) This paper will summarize the status of the Matsushima plant operational results and the optimization and examination of impurity removal efficiency within the individual plant components. In addition, the current status of the 500 tpd CO2 capture demonstration plant project will be reported. (10) MHI, as a heavy industrial equipment manufacturer, can provide an integrated plant design through the provision of power generation equipment, flue gas clean up, process plants and CO2 compressors. MHI is actively developing solutions to mitigate global warming through the deployment of economically efficient environmental control technologies and advanced optimization of plant equipment. Related activities such as the large scale demonstration of CO2 capture, with our global partners, are important steps leading to the commercialization of this technology for application in the coal fired power generation sector, thus helping to reduce atmospheric industrial emissions of CO2. (C) 2011 Published by Elsevier Ltd.
