Kawasaki Heavy Industries' coal-fired power plant ash slag treatment equipment adopts dry treatment

Figure: Construction of a slag handling system for dry ash handling equipment

Kawasaki Heavy Industries received orders for two coal ash slag processing facilities from the "Kobe Iron Works Thermal Power Station" (tentative name) built by the Kobe Steel project. Kawasaki Heavy Industries will be responsible for the entire business from design, manufacturing, equipment procurement to installation engineering. It is planned that the first station will be completed in 2021 and the second station will be completed in 2022.

Ash processing equipment is a system for treating the combustion ash of coal used as power generation fuel. It consists of two parts. One is a system that processes the soot (the dust contained in the exhaust gas) captured by the electric dust collector. It is a system that processes the slag (bottom ash) discharged from the bottom of the boiler. The two ash processing facilities will be installed in the two units planned for construction of the power station (power generation output of 650,000 kW×2).

The slag treatment adopts the “dry slag conveyor belt processing method”, and the related technology was imported from Magaldi Company of Italy. The specific process is to directly use air to cool the slag and then pulverize it and then transport it to the soot handling system (see figure).

This kind of dry treatment can not only process slag and soot uniformly, but also does not require equipment such as water supply and drainage, dehydration, and water storage. Therefore, the environmental load can be reduced, the cost can be reduced, and the space required can be reduced. In addition, the sensible heat of the slag, the reaction heat of the unburned coal, and the radiant heat of the furnace can also be recovered to increase the efficiency of the boiler.

However, the commonly used wet treatment methods are different. It is necessary to use water to cool and transport the slag. After dewatering, the slag is transported to the waste residue yard by trucks.

Kawasaki has outstanding performance in dry ash handling equipment. Since the delivery of No. 1 aircraft to Kobelco Kobe Power Station (Kobe City) in 2002, it has received 12 orders in Japan, including this order. If it includes a wet treatment method, Kawasaki Heavy Industries has supplied 60 ash processing facilities to Japan's commercial coal-fired power plants, with a share of approximately 80%.

At present, there are plans for new or additional thermal power stations in Japan. Kawasaki will continue to supply equipment for power generation equipment such as ash slag treatment equipment and will actively carry out business in the energy and environmental fields. (Reporter: Matsuda Chiho)