Maintenance and maintenance of the reactor

Stainless steel reaction kettles are generally kettle-type reactors with stirring devices, which are typical equipment used in chemical, pharmaceutical, dye, paint, etc. As a typical equipment commonly used in industrial production, the jacket also has the meaning of interlayer, mainly by introducing heating medium inside the jacket. So as to complete the function of humidification or heating in the kettle.

In daily production, once the reactor is damaged, it is irreversible. Therefore, the importance of daily maintenance becomes apparent. Today, JCTwill give everyone a vaccination.

1. Main manifestations of illegal work

If the stainless steel reaction kettle is not replaced or the replacement is not complete, the test run or the manhole is opened for welding maintenance, and the air enters the kettle to form an explosive mixture and explode. Use flammable gas (such as the refining gas of the synthesis system, the shift gas of the carbonization system) to make up the pressure, test the pressure, and test the leak. Hot work is carried out without hot fire analysis and hot treatment (such as no blind plate is added to isolate the maintenance equipment from the production system, or the quality of the blind plate is poor, or asbestos plate is used as the blind plate), and the hot work is carried out without a hot fire certificate. Bolts for valves and flanges of pressure-tightening equipment. Blind pursuit of output, overpressure, overload operation. Unauthorized lowering of the liquid level in the storage tank makes the water seal ineffective or the positions do not cooperate well, causing the compressor and pump to be pumped negatively, allowing air to enter the equipment to form an explosive mixture. The change of process parameters in the equipment was not detected in time when the equipment was in operation, resulting in the explosion of oxygen in the system.

2. The main types of operational errors

When the equipment is replaced and cleaned, the replacement sequence is wrong. Staggering the valve during operation, or not opening and closing the valve in time, or the wrong sequence of opening and closing the valve, will cause the equipment to hold back pressure or the gas to flow back and overpressure, causing a physical explosion. Feeding too fast or feeding unevenly causes a sharp increase in temperature, or solidifies the mother liquor in the equipment. Failure to discharge condensed water in time or improper operation will cause the equipment to operate with water overpressure. Compressor and pump suction caused by operational reasons allows air to enter the equipment and form an explosive mixture. Prematurely stopping the pump and water will cause local overheating, melting and perforation of the equipment. Throwing the wrong material will cause it to decompose and explode in the recycling process. Staggering the outlet valve of the oil tank will cause the roof to overflow and explode in case of an open fire.

3. The main manifestation of poor maintenance

During the operation of the stainless steel reactor equipment, the leakage of flammable gas is caused by the leakage of the instrument connection and the poor sealing of the valve. If the sediments (such as yellow phosphorus, brick mud, and carbon deposits) are not cleaned in time, the pipeline will be blocked, causing the vacuum degree of the equipment to rise, air will enter the gas pipeline through the water seal, an explosive mixture will be formed in the equipment, or the carbon deposit will spontaneously ignite and explode at high temperature. Failure and damage of instrumentation devices, such as failure of the hydrogen automatic venting device, air entry; failure of the gas-making furnace gas downward valve during driving, resulting in an increase in oxygen content, even as high as 4.2%; failure of the check valve on the vacuum pipeline of the condensation tank, and part of the water entering The tank caused a violent chemical reaction and exploded, and the copper liquid level gauge broke and detonated. The non-condensable gas is not exhausted or exhausted, resulting in an overpressure explosion. Epoxy resin is used as a preservative to cause fire when applied to equipment. If the equipment is stored for a long time, the temperature is too high to cause self-polymerization reaction, or the filling of flammable liquefied gas is too full, and the gas is heated and expanded during storage and transportation at high temperature, and the pressure rises sharply, resulting in an explosion. The accumulation and loss of control of the oil vapor discharged from the oil vapor emission source into the atmosphere, and the volatilization of the residual product, form a flammable and explosive system around the oil tank area. on fire. There are ignition sources, mainly referring to welding fires, motor vehicle exhaust sparks, electrostatic discharges caused by failure of static elimination devices, lightning strikes, and other ignition sources, such as iron collisions, sparks generated by the friction between nails and shoes, and the road surface.

4. Manufacturing defects mainly include the following

The materials of self-made or self-modified equipment do not meet the requirements, and they are not processed in accordance with relevant regulations and technical requirements. The welding quality is very poor, such as the obvious lack of fusion with the base metal, continuous point slag inclusion, pores or small cracks at the welding point of the equipment, or the outer wall is welded on one side, the groove is not opened, the thickness of the welding meat is uneven, and the welding seam The inner clamp pad round steel and other metals. The stainless steel reactor equipment is not processed strictly according to the drawings, leaving hidden dangers for equipment accidents. For example, the biphenyl heating water jacket of the hydrolysis kettle cannot be removed due to the wrong processing of the return pipe head, and the water accumulated in the lower part of the pipe head cannot be removed, resulting in a sudden explosion of the hydrolysis kettle due to heating and boiling. Use old equipment or substitute equipment, due to unknown material properties or its own defects, such as outdated equipment, valves and heads that cannot be opened for a long time, check valves installed in wrong positions, unable to prevent fluid backflow, etc., or the use of atmospheric pressure equipment. explosion occurs.

5. The phenomenon of chemical corrosion is as follows:

electrochemical corrosion and hydrogen corrosion are serious, which make the local wall thickness of the equipment thin or become brittle. The tower wall is severely corroded and partially perforated. The equipment and parts are broken due to corrosion, and the equipment leaks due to corrosion.

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Jin Chang Tai Chemical Machinery Co.,  Ltd.

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