Various kinds of combined cycle power generation system have been proposed for efficient use of abundant energy resource, coal. Pressurized fluidized bed combustion
(PFBC) combined cycle system has the following features in general and has gotten much attention from Japanese utilities owing to its earlier practical use.
1. High plant efficiency and low auxiliaries power consumption
2. Low emission such as de-SOx by in-bed desulfurization, minimizing NOx by low combustion temperature and decreasing CO2 by high plant efficiency
3. Compactness by eliminating flue gas desulfurization equipment and reducing the equipment size due to less volume of pressurized air/gas
Development of PFBC system started in England in 1960s and it was taken over by ASEA (later ABB). Three plants were installed by ABB Carbon in 1989 and 1990. One in Sweden which consists of two PFBC boilers/gas turbines and one steam turbine is a commercial cogeneration plant supplying 135MW electricity and 224MW hot water. The others installed in USA and Spain are demonstration plants with electric output of 70MW and 79MW respectively.
In Japan, the first PFBC plant was installed at Wakamatsu Coal Utilization Research Center of Electric Power Development Co., Ltd. with government support and its demonstration operation has already commenced since the end of 1994. Construction of commercial plant has also started.
Ishikawajima-Harima Heavy Industries Co., Ltd. (IHI) delivered Wakamatsu PFBC boiler under the technical license from ABB Carbon with various new technologies incorporated to realize better performance in efficiency, emission and operationability required in Japan. Its main specific features are as follows.
—Combination with the existing steam turbine having ultra-high steam temperature, 593/593 deg. C.
—The first PFBC boiler with repeater
—Additional environmental equipment, such as ceramic tube filter and selective catalytic reduction
This paper summarizes the feature of PFBC system, IHI's development of PFBC and the outline of Wakamatsu PFBC plant with its operation experience. Further considerations for PFBC now such as confirmation of long term operation reliability, combustion of various kinds of coal and increase of performance are also discussed.
