The Jiahua Power Co. Ltd. is a coal driven 6 x 600 MW power plant in Jiaxing, China. The power plant has three 230 m high chimneys. Two chimneys have steel liners, one has no liners. That chimneys are made of reinforced concrete with a brick lining on the inside. The brick liner on the inside of the chimney was in good condition and the joints between the bricks were on the average very small and closed level. Due to changes in the flue gas cleaning system of the power plant, the temperature of the flue gas that is lead through the chimney will be considerably lower in the future than it is today. The lower temperature of the flue gas will lead to an increased formation of condensate on the inside of the chimney. This condensate contains H2SO3 and H2SO4 due to constituents of the flue gas, thus leading to a constantly wet acidic environment on the inside of the chimney. The ph value of the flue gas was expected to be between 2 and 3. In order to protect the masonry on the inside of the chimney, the surface received a protective coating which can withstand exposure to acids.
The inside of the chimney was coated in the following steps:
First, the masonry substrate was cleaned using high pressure water cleaning. After that, a layer of KÖSTER NB 1 Grey was sprayed on using the KÖSTER Variojet FU-KB Spiral Pump. Then, as last work step and final top coat, KÖSTER PSM was sprayed on to the inside of the chimney again using the KÖSTER Variojet FU-KB Spiral Pump.