1： Abrasion and corrosion analysis of dust collection system:
cement The main components of raw materials required are Fe two O three 、 CaCO three 、 Si O two 、 Al two O three Etc., by limestone （ 76.4%), loess (13.05%), coal (3.2%), iron powder (1.85%) and fluorite (0.5%), calcine the mature material at about 1500 ℃ and then add appropriate amount Gypsum It is made by grinding slag. It becomes alkaline when it meets water, and has the characteristics of high dispersion, strong adhesion, hygroscopicity and corrosiveness. The pH value of cement dust is about 10-12, which is strongly alkaline, so there is an alkaline corrosion environment in the dust remover.
Due to high flue gas humidity and high dew point temperature, if the dust collector has air leakage, insulation failure or other Defects: the flue gas is easy to dewfall after the temperature drops, and the harm of dewing will not only cause The impact of "pasting bags" will also cause alkali corrosion to the metal parts of the precipitator. The flue gas in the cement plant is generally between 220 ℃ and 350 ℃. If the steel structure of the dust remover is not protected against corrosion and oxidation, the oxidation and corrosion of the metal steel structure will be very serious. The falling rust will not only pollute the finished products, but also the uneven oxidation and corrosion surface will affect the normal flow of the flue gas. A large amount of dust will gather locally, which will seriously affect the normal production of the cement plant.
In the process of denitration in cement plants, ammonia water is mostly used as the reducing agent. Excessive spraying of ammonia water will directly pollute the equipment. Ammonia has strong adsorption and corrosivity, and it is difficult to eliminate equipment attached to flue, dust collector, etc., which will gradually cause corrosion to the equipment. At the same time, ammonia water is easy to decompose into ammonia gas, and the higher the temperature, the faster the decomposition, ammonia In humid environment ionization Ammonium ion and Hydroxyl ion formation electrolyte solution , promoting metallic Galvanic reaction And accelerate the corrosion of metal ; Ammonia molecules can interact with many transition metal Ions form complexes to make them soluble in water and peel off the oxide film protecting the metal surface. During denitration, excessive ammonia will form ammonia gas, which will cause corrosion to metal equipment such as rear dust collector equipment and flue, so anti-corrosion measures are urgently needed.
In the cement kiln with collaborative waste treatment, the composition entering the kiln tail dust collector becomes more complex due to the addition of waste. There are not only normal process materials that can generate acid compounds, but also a large number of chloride ions, fluoride ions, trace organic compounds, various complex compounds and other unpredictable corrosive media. The corrosion of the dust collector of this kind of cement kiln is more serious after garbage treatment.
The cement plant has high flue gas velocity and high dust concentration, so the erosion and abrasion of the flue gas on the metal steel structure is very serious. The rust layer after corrosion is continuously eroded and abraded, exposing new substrate, causing further erosion and thinning of the substrate.
If the dust collection equipment is coated with anti-corrosion and wear-resistant coatings, the coatings must have the following characteristics:
Acid and alkali resistance;
High temperature resistance of 400 ℃ (taking into account the extreme operating temperature and certain temperature tolerance allowance);
High hardness of paint film, abrasion resistance and impermeability;
The paint surface is smooth without dust;
Conducting static electricity, leaving no static charge generated by friction;
Resistant to ammonia corrosion.
2、 Material introduction and product matching
Material Introduction
ZS-1041 smoke anti-corrosion coating is based on inorganic siloxane - Si-O-Si - bond as the main chain, grafted with a variety of organic functional group side chains as the auxiliary, with nano silicon powder, nano graphite flakes, silicon carbide, boron nitride, fine alumina, ultra-fine zinc oxide, titanium oxide, ceramic beads, micro powder zirconia, etc. Combined with the working condition of cement kiln collaborative waste treatment, the comprehensive anti-corrosion performance of the modified cement kiln is further enhanced. The working principle of interaction and synergistic effect of each component of the coating makes the coating have comprehensive excellent properties such as high temperature resistance, electrostatic conductivity, low surface energy, high acid and alkali corrosion resistance, high hardness, and strong adhesion with the substrate.
It has been widely used in the kiln tail dust collector, chimney flue and other parts of the cement plant for collaborative treatment of garbage and hazardous wastes, which are resistant to high temperature, acid and alkali corrosion, abrasion and dust erosion.
Product supporting
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Product name
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do use
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remarks
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ZS-1041 smoke anti-corrosion coating
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Anti corrosion, high temperature resistance and smoke prevention
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Design film thickness 0.3mm
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Process Overview
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Sand blasting or manual derusting of the substrate to be constructed for the chimney, and the substrate treatment and acceptance;
Weld joints and corners shall be pre painted once in advance ZS-1041。
Full surface painting ZS-1041 flue gas anti-corrosion coating is applied four times (one time for pre coating of fillet weld, three times for overall construction);
The above anti-corrosive coating shall be applied once the surface is dry, and the next one shall be applied at intervals About 2 hours, the temperature of winter construction is low, and the interval between each pass can be appropriately extended.
Acceptance of coating film thickness integrity and no leakage
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5、 Construction steps
1. Preparation before construction
Including material preparation, sand blasting and rust removal tools, cleaning tools, painting tools, labor protection appliances, iodine tungsten lamp or other auxiliary heating equipment preparation.
2. Bag protection
Block the perforated plate holes of the air cleaning chamber or cover the filter bag holes with a cover plate to prevent foreign matters from falling into and damaging the filter bag during construction.
3. Substrate treatment
For the cabin with repair and welding completed, the weld and welding slag shall be polished and trimmed, and emery sand blasting shall be used to ensure that there is no dust, oil stain, debris, rust, brittle layer and moisture on the surface of the substrate to be painted（ <10%) and other foreign matters that may affect adhesion, up to Sa two point five Grade, guaranteed base material two Roughness of 0~40 μ m. Set up temporary mobile canopy to cover sandblasting cabin to prevent dust from flying. Clean the cabin after sand blasting to ensure that the surface of base material is free of dust and dregs.
4. Antiseptic coating preparation
Painting: ZS-1041 smoke anti-corrosion coating is two-component, component A (in plastic bag), component B (in small iron bucket), and black component A will precipitate. Before use, component A will be fully and continuously stirred evenly, then stirred according to the specified proportion, and fully mixed with electric mixing equipment 2~ 5 minutes.
5. Anticorrosive coating pre brushing
The mixed paint shall be used to pre coat the parts that are not easy to be painted in large area construction such as welding seams and corners after sand blasting and cleaning.
6. Overall application of anti-corrosion coating
The overall painting can be done by spraying machine or by roller brushing The design thickness is reached by multiple construction.
7. Operator protection
There will be some odor volatilization during coating construction. Operators shall wear protective tools during construction to avoid excessive inhalation or direct contact with skin.
8. Tool cleaning
Summarize and collapse the unused tools; After painting, the painting tools shall be cleaned and dried with organic solvent immediately.
