Nakoso IGCC plant

On the last day of the 10th China-Japan Symposium on Fluidization, today I got an opportunity to visit the Nakoso IGCC (Integrated coal Gasification Combined Cycle) demonstration power plant located in Fukushima Prefecture of Japan. It was a great experience to have direct acquaintance with a clean coal power generation technology which is still under R&D stage worldwide.



Coal is a widely distributed and abundantly reserved fossil fuel that can ensure stable supply for future power generation. However, conventional coal combustion steam-electric plants make use of heat produced from burning coal, which results in low efficiency and high emission of pollutants including carbon dioxide. Therefore, clean coal technologies such as IGCC and IGFC (Integrated coal Gasification Fuel Cell) have been the focus of current R&D in this field. In IGCC technology, coal is converted into gaseous products, known as syngas (composed of hydrogen and carbon monoxide). Before the syngas is burned in a gas turbine to produce electricity, impurities can be removed from the fuel and turned into re-usable byproducts. This results in lower emission of pollutants such as particulates, sulfur dioxide and mercury. This capacity for pre-combustion clean-up of pollutants is one of the technology’s primary advantages over conventional coal combustion approaches. Moreover, to improve overall process efficiency, heat is recovered from both the gasification process and also the gas turbine exhaust in waste heat boilers producing steam. This steam is then used to produce additional electric power.

Several IGCC demonstration plants are now under construction or undergoing demonstration operation across different parts of the world. In Japan, as a national R&D project, a 200 ton/day entrained bed coal gasification combined cycle pilot plant (25 MW) was constructed and operated for 4770 h from 1991 to 1996 by the IGC Research Association under the sponsorship of NEDO (New Energy and Industrial Technology Development Organization), and was successfully completed in March 1996. Based on this experience, Clean Coal Power R&D Co. Ltd. was founded in 2001 in collaboration between Japanese government and Japanese electric power companies to construct a 250 MW IGCC demonstration plant. It is the same demonstration plant which is now commonly known as “Nakoso” from the name of the place where it is located. It has come into operation from September 2007.

Process flow diagram of the Nakoso IGCC plant

Details of the Nakoso IGCC plant as well as some basics of IGCC technology can be found here.