For the installation and management of industrial equipment, it should always be the focus of attention of enterprises, fire protection and safety supervision departments, especially the various towers, tanks, kettles, reactors, filtration, drying, heat exchange and other stereotyped or non-stereotyped equipment of chemical enterprises, and its safety measures can not be ignored in the slightest!
1. Cases of leakage accidents
A major spill occurred at a liquefied petroleum gas station. At 8:30, two employees of the LPG station went to the gas storage tank area in the backyard of the gas station to inspect and found that there was a valve at the bottom of the No. 3 tank that was a little leaking. They originally wanted to replace the valve sealing gasket, but the result was not properly handled, after the screw was disassembled, a large amount of liquid rushed out of the valve screw hole, quickly vaporized, and formed a mist gas in the tank farm, which diffused with the wind.
At 8:50, the fire brigade immediately dispatched after receiving the alarm, and took decisive measures to extinguish the open flame source within 500m around, block the 312 national highway in front of the station, implement traffic control, open the automatic sprinkler device in the tank area, use the spray water gun to disperse the mist, and use the tanker to release the leakage tank gas storage, at the same time, organize the firefighters to risk their lives, go deep into the interior to block the vent, after 6 hours of fighting, in l4 o'clock to eliminate the danger, to avoid a major accident.
2. Analysis of the cause of the leakage
Equipment pipeline leakage is widely present in the production, storage and transportation of chemical enterprises. As far as the premises are concerned, there are almost everywhere in the factory building, various equipment within the framework, liquid cylinders, storage tanks and vehicle tanks, various pipelines crisscrossing the factory area, etc.
There are many reasons for leaks, both on the equipment and on the process. To sum up, the main ones are:
1. The strength performance of the equipment material is reduced. Such as corrosion, thermal influence, etc.
2 Subjected to external loads. Such as vibration, pressure load, bump, smash, etc.
3. The internal pressure increases. Such as thermal expansion, mechanical compression or adiabatic compression, water hammer and other physical causes, as well as combustion reactions, exothermic decomposition reactions, reaction runaway, evaporation, etc.
4. Process operation errors. Such as process operation errors, improper control methods, etc.
According to the analysis of the statistical data of leakage accidents in petrochemical enterprises at home and abroad, the accidents caused by corrosion of equipment and materials and human misoperation are the most common. Therefore, the leakage accident during the operation of the equipment must be focused on.
3. Preventive measures
1.It is necessary to correctly select the wall material of the equipment, accurately allocate the equipment components and parts, and the structure should be reasonable and the process should be appropriate. In individual cases, with the help of electrochemical methods, metal protective coatings can be used, anticorrosive paint or anticorrosive layers lined with tiles, glass and other materials, and resists can also be applied or enamel equipment, graphite equipment, plastics and other equipment can be used to replace metal materials and equipment, as well as to educate workers on the knowledge of corrosion prevention to reduce the leakage caused by corrosion rupture.
2.The key to preventing operation errors is to strengthen the ideological and professional education of operators, so that they can understand the factors that affect the damage of equipment and affect the life of equipment, master the skillful operation technology and the method of eliminating hidden dangers and failures, and formulate binding rules and regulations. It is also necessary to strengthen the protective measures of containers and pipelines, such as installing protective nets, setting up partition walls, and ensuring safe distances.
In addition, it is necessary to strengthen inspection and maintenance management, establish a reliable automatic control system and scientific management system, so as to facilitate early detection, rapid control, and prevention of leakage.
Fourth, plugging measures
Once a leak is found during the operation of the equipment, temporary or fundamental measures should be taken quickly to prevent the leakage from continuing.
1.Plugging and patching vulnerabilities in real time is an important part. The method of plugging the leakage must adopt different disposal methods according to the form and location of the leakage. If the fastener is loose, it is fastened; Due to the damage of the gasket, that is, the ring should be replaced; When the equipment is partially corroded and cracked, it should be repaired in time to prevent the crack from further expanding, which is quite dangerous and must be based on the premise of safety.
2.For leakage accidents that cannot be welded and plugged during operation, such as disposal with plugging materials such as cement and asbestos; For those with large cracks and no temporary plugging measures, it is best to pour or stop, cut off the gas source, replace and clean it, and then weld or dismantle it, and strictly test and inspect, especially to ensure the quality of the weld.
3.If a leak has occurred and cannot be stopped, the first thing is to remove all fire sources that may affect the range within a certain time interval between the leakage and the fire, and control its spread by means of extinguishing and dispersing; For combustible gases with a short leakage time but a large amount of discharge or high toxicity, they can also be deliberately ignited and burned out under supervision to avoid the danger of deflagration.
It should also be emphasized that the waste flammable liquids and liquefied petroleum gas residues should be properly disposed of, and should not be discharged casually, let alone poured into the gutter. All enterprises that produce and store flammable and explosive liquids shall build grease traps and water-sealed wells in front of the sewage tank to prevent flammable and explosive liquids from entering the sewage tank and sewer channels.
Device management