Cement plant maintenance and anticorrosion engineeringDate: 2019-08-20 Views:
Cement plant anti-corrosion engineering to do well, or once the accident caused by the termination of production, resulting in greater losses, this paper mainly introduces cement plant maintenance anti-corrosion engineering.
1. Brief introduction of main structure (production line) of anti-corrosion
The production line of cement factory usually includes raw material storage, uniform material storage, preheater room, rotary kiln, mixing room, packing room, finished product storage and various air ducts.Among them, the main equipment and components that need paint anticorrosion are preheater room steel structure, preheater, three-time air duct, etc.
1.1 the preheater is mainly composed of a cyclone tube and a slide tube, which are used to preheat raw materials.
1.2This is the pipe that delivers high speed and high heat flow to the preheater.
1.3 steel structure of preheater room the steel structure that provides support platform for the preheater.
2. Corrosion analysis
2.1 equipment structure features
High temperature equipment such as cyclone tube, slide pipe and three-time air pipe are equipped with fire prevention and heat insulation materials in the inner wall, as shown in the figure below:
2.2 corrosion analysis
According to the cement plant and a number of visits and inquest, whether in the preheater room built steel structure processing process is ignored in the making process of the equipment corrosion, performance in the pretreatment of the structure and surface treatment are poor, welding slag, spatter, flash, cutting tumor is not clear, affect the appearance of rough cutting notch is not clear or polishing smooth, in good condition under the paint film of the surface of the substrate processing incomplete or not.
In addition, uneven laying of fireproof and heat insulation materials on the inner wall of the equipment and the shedding of local heat insulation materials in the process of production operation lead to obvious inconsistent thermal corrosion.In addition, uneven flow of raw materials in the tube and tube during production can also cause temperature difference in the same place at different times.The temperature difference between the welds in the cyclone tube and around the welds was detected by field inspection, although they were less than 10 cm apart.
3. Matching selection of paint
According to the different temperature of each part of the production line, anti-corrosion equipment and components are divided into normal temperature components and high temperature components.Normal temperature components such as preheater room steel structure and the operation of the platform, high temperature components such as cyclone tube, pipe, three air duct.
For normal temperature components, we can choose a conventional epoxy primer with polyurethane finish.And for high temperature components, due to the temperature difference of various parts is very large and uncontrollable, in order to simplify the paint matching and construction, we can choose the temperature unit more broad silicone heat resistant paint or inert copolymer heat resistant paint.
Because the organic silicon heat resisting paint needs to use the inorganic zinc silicate primer to play a better anticorrosive performance, and their temperature resistance range is relatively not broad, the construction is complex, so it is recommended to use the inert copolymer high temperature resisting paint.
4. Paint construction
4.1 surface treatment
According to the interviews with some of the owners, although we all understand that surface treatment is crucial to the anti-corrosion performance and service life of the final paint film, none of them are willing to carry out a comprehensive surface pretreatment and remove all the old coating before carrying out a thorough surface treatment.
According to this situation, we suggest to use sandpaper disk to polish the corroded parts to St3 level, while use sandpaper to clean the other parts with intact paint film.
Before painting construction, use high-pressure compressed air and broom to completely remove dust from the coated surface.
4.2 paint construction
Prior to the unified coating, brush is used to precoat the polished steel substrate and other parts, so as to avoid air trapped in the area and forming a cavity during the unified coating.Precoating complete, then unified coating.
Pay attention to ensure that the dry film thickness meets the design requirements, and make the final paint film to form a continuous, uniform, smooth protective layer.
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