Preparation before constructionMaterial preparation:
Select organic silicon high-temperature resistant coatings that are suitable for the petrochemical environment, ensuring that their quality meets relevant standards, such as temperature resistance level, chemical corrosion resistance, and other indicators that meet the requirements for on-site use. At the same time, prepare supporting auxiliary materials such as diluents and curing agents (if it is a two-component coating).
Check the shelf life and packaging integrity of the coating to avoid using deteriorated or damaged coating products.
Tool preparation:
Prepare the necessary tools for construction, such as airless spraying equipment, air spray guns, brushes, rollers, etc. Choose the appropriate tools according to the actual situation and construction requirements of the construction site.
Clean and debug construction tools to ensure they can work properly, such as checking the sensitivity of pressure adjustment and the good atomization effect of the spray gun for airless spraying equipment.
Site and substrate preparation:
The construction site should ensure good ventilation and try to eliminate flammable and explosive gases, dust, etc. that may exist in the petrochemical industry. At the same time, safety protection measures such as fire and explosion prevention should be taken.
Pre treatment of substrates that require coating, such as reaction vessels, distillation towers, heat exchangers, etc., includes thorough cleaning to remove impurities such as oil stains, rust, and old paint layers. Chemical cleaning, mechanical polishing, sandblasting, and other methods can be used to achieve the specified surface treatment standards (such as Sa2.5 level) to improve the adhesion between the coating and the substrate.
Paint blending
Single component coating: If it is a single component silicone high-temperature resistant coating, simply dilute it appropriately with the matching diluent and adjust the viscosity of the coating to a suitable range for application. The dilution ratio is usually carried out according to the requirements of the coating product manual. The amount of diluent added is generally around 5% -15% of the total amount of coating. By stirring evenly, the coating can achieve good fluidity and application performance.
Two component coating: For two-component organic silicon high-temperature resistant coatings, the curing agent and main paint should be accurately weighed according to the specified ratio in the manual, with a general error controlled within ± 5%. Then, the curing agent should be slowly added to the main paint, and an electric mixer should be used for thorough stirring at a moderate speed for no less than 5 minutes. After ensuring that the curing agent is completely mixed with the main paint, an appropriate amount of diluent should be added to adjust the viscosity, and the viscosity should also be adjusted to a suitable level for construction.
Construction operation
Spray coating construction (commonly used):
Airless spraying: pour the prepared coating into the material tank of airless spraying equipment, and adjust the spraying pressure. Generally, the pressure is about 10-20MPa according to the nature of the coating and construction requirements. The operator holds the spray gun and keeps it perpendicular to the surface being coated, with a distance controlled at around 200-400mm. The spray gun is moved at a uniform speed to evenly cover the substrate surface, avoiding phenomena such as sagging and missed spraying. When spraying, the principle of starting from top to bottom and starting from difficult to easy should be followed to ensure that all parts can be effectively coated.
Air spraying: During air spraying, adjust the pressure of the air compressor, usually between 0.3-0.6MPa, to atomize and spray the coating under the action of compressed air. The distance between the spray gun and the substrate surface should be kept at around 150-300mm, and the spray gun should be moved at an appropriate speed to ensure a uniform and smooth coating. However, air spraying may be more prone to paint mist flying and slightly lower coating utilization compared to airless spraying. Operators need to pay attention to controlling the spraying angle and speed.
Brush coating construction: For some complex shaped and difficult to spray parts, such as corners, gaps, bolt connections, etc. of equipment, brush coating can be used. Choose a high-quality brush, dip it in an appropriate amount of paint, and evenly apply it to the surface of the substrate in a certain direction (such as from top to bottom, left to right) to avoid brush marks, sagging, and other phenomena, ensuring that the coating is flat and uniform in thickness. The thickness of each coat should not be too thick, generally controlled at around 20-50 μ m. Wait until the previous coat is dry before applying the next coat.
Rolling coating construction: Rolling coating can also be used in some large-area flat areas with relatively low appearance requirements. Dip the coating onto a roller and roll it back and forth on the surface of the substrate to evenly spread the coating. During the rolling process, pay attention to maintaining the moisture level of the roller to avoid uneven coating caused by dry rolling. Similarly, wait for the previous coating to dry before proceeding to the next rolling process.
Coating curing
Natural curing: Some organic silicon high-temperature resistant coatings can naturally cure at room temperature. After construction, place the coated equipment in a well ventilated and dry environment to avoid contamination of the coating by dust, impurities, etc. Let it naturally dry and crosslink according to the curing characteristics of the coating to form a stable coating structure. The natural curing time generally takes several days, and the specific duration is determined according to the requirements of the coating product manual.
Heating curing: Some coatings require heating curing under certain temperature conditions to improve the performance and curing speed of the coating. The equipment for coating can be placed in a dedicated oven, or the heating function of the equipment can be used (if allowed) to heat the coating according to the specified curing temperature curve (such as first heating to a certain temperature and holding for a certain period of time, then gradually heating to a higher temperature and holding for the corresponding time, etc.), so that the coating is fully cured. During the heating and curing process, temperature, time and other parameters should be strictly controlled to ensure compliance with the coating requirements.
Quality inspection and repair
Appearance inspection: After curing, inspect the appearance of the coating to see if it is flat, smooth, and free of defects such as sagging, bubbles, pinholes, and peeling. For areas that do not meet the requirements, mark them for subsequent repairs.
Thickness detection: Use professional tools such as coating thickness gauges to detect the thickness of the coating, ensuring that the coating thickness meets the design requirements. The dry film thickness of the organic silicon high-temperature resistant coating for general petrochemical equipment is around 100-300 μ m. If the thickness is insufficient, it needs to be repaired until the specified thickness is reached.
Repair: For areas where quality problems are found during inspection, such as local peeling, pinholes, etc., the problem area should be cleaned first to remove the damaged coating, and then the coating mixing, construction, and curing operations should be carried out again according to the above construction process to ensure that the coating quality meets the requirements and to guarantee the effective protective performance of the equipment in high-temperature and corrosive environments in the petrochemical industry.

Room termperature curing polysilazane, pls check IOTA 9150, IOTA 9150K.    
High termperature curing polysilazane, pls check IOTA 9108, IOTA 9118.