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Analysis and prevention of catalytic cracking accidents http://bbs.hcbbs.com/viewthread.php?tid=252399&highlight=%B4%DF%BB%AF%C1%D1%BB%AF%CA%C2%B9%CA%B7%D6%CE%F6%D3%EB%D4%A4%B7%C0

6.1 The catalytic cracking workshop is prone to accidents. As one of the important devices in the refining industry, the catalytic device coexists with chemical reactions and physical separation during the production process. The device has strong production continuity, many high-temperature and high-pressure equipment, the products are flammable and explosive, and the process is complex. Material processing and transportation are carried out in a closed state. The degree of automation is high and the operation requirements are very strict. It is particularly important to master and strictly implement its specific indicators. The implementation of the patrol inspection system of the position is also very important. 6.1.1 Fractionating tower feed oil and gas * * Phenomenon and causes of orchid leakage: The temperature of the oil and gas flange is high. If the flange bolts are not tightened evenly, leakage accidents will easily occur when pressure and other operations fluctuate. Because the memory medium is high-temperature oil and gas, smoke will emit when the leakage is minor. When the leakage is severe, the oil and gas will spurt out and ignite spontaneously. If not discovered in time, the combustion time will be too long, which will cause serious consequences. Prevention and treatment: Arrange post inspection signs at this location to strengthen post inspections. There is a fire steam vent on this floor platform, and a fire steam hose is connected for backup. Once a danger occurs, fire steam should be turned on immediately to the fire location to extinguish the fire. The decision should be made based on the actual situation whether to cut the material. If the fire is large and difficult to extinguish, the material must be cut immediately, use fire steam to control the fire as much as possible, and ask the fire brigade for support. 6.1.2 Causes and phenomena of liquefied gas leakage in Tower 302 (liquefied gas reflux tank at the top of tower 303): In winter production, if the dehydration of the container 302 is not timely, the water in the dehydration valve at the bottom of the tank will easily freeze and crack, causing a large amount of liquefied gas to leak out, causing serious consequences. If there is static electricity or an open flame, it will cause an explosion accident. Prevention and treatment: There is a flammable and explosive gas concentration alarm in container 302, and fire steam hoses are installed at both ends of the platform. Once a leak occurs, liquefied gas can easily cause frostbite. Use fire steam to cover it, close the valve connected to container 302, and use steam to dilute the concentration of liquefied gas. All personnel should stand upwind to avoid poisoning and frostbite accidents. At the same time, the operators in the central control room will adjust operations. , set off the rich gas flare, stop the gas compressor, set off the torch in Capacity 302 to relieve pressure, stabilize the system and treat it as an emergency shutdown, withdraw the T303 heat source, cut off the feed to T303 to prevent tower 303 from being over-pressured. If a fire accident occurs, while using steam cover to prevent the spread of the fire, cut off all pipelines connected to it, and ask the fire brigade for support from the foam fire extinguishing system. All positions in the device will be treated as an emergency shutdown. Processing principles: When encountering such an accident, the shift leader and operators must be calm, distinguish the priorities, and must not be eager for success. They must cooperate on the job and try to avoid personal injury accidents. Once liquefied gas poisoning occurs, quickly leave the scene and go to fresh air. If breathing is difficult, perform artificial respiration immediately and send to the medical department for treatment as soon as possible. 6.1.3 Causes and phenomena of installation trench fires: Such accidents are generally likely to occur during start-up and shutdown. There is some dirty oil discharged due to venting in the trench, as well as light oil leaked in due to improper operation. Because the light oil in the catalytic device is highly volatile, a large amount of oil and gas will be formed. Once it encounters static electricity or sparks, it will explode or burn. After a fire occurs in the trench, the front line will be long and it will be difficult to extinguish. Prevention and treatment: A total of six fire-fighting steam hoses are installed in the pipe gallery from south to north, which may be used at any time. Strengthen inspections during production, pay attention to observation, and promptly clean up the oil stored in the ditch. When light oil is found, wash it with water in time. Once a fire occurs, fire-fighting steam will be turned on in all places at the same time. First, identify the heavy oil. For important parts, such as the water cut-off point in the stable zone 201, use a fire extinguisher to cooperate, cut off the normal and decompression baffle of the trench, and ask the fire brigade for support. Indoor operators must be calm to avoid large fluctuations in the operation, and decide whether to perform emergency shutdown according to the fire extinguishing situation. 6.1.4 Hot oil pump leaks and catches fire. This device has hot oil pumps such as slurry pumps. Once the seal leaks, it is very easy to catch fire, which is very dangerous. In addition to daily inspections, pay attention to the inspection. The cooling water of the pump cannot be turned down. After the leakage occurs, deal with the problem according to the leakage situation. If it is a minor leakage, high-temperature oil leakage will produce yellow smoke when exposed to oxygen. If it is found, stop the pump quickly and remove the pressure. Close the pump inlet and outlet valve and activate the backup pump. If the leakage is serious and has caught fire and you cannot get close to the pump, you must contact us quickly. The electrician cuts off the power to the pump in the power distribution room, uses fire-fighting steam and fire extinguishers to suppress the fire, and at the same time closes the extraction valve device at the bottom of the medium tower and closes the nearest valve at the pump outlet to prevent the spread of the fire. If the fire can be extinguished in a short time, close the pump inlet and outlet valve, improve the system flow, activate the backup pump, and adjust the operation. If the fire cannot be eliminated in a short time, it must be treated as an emergency shutdown. Once the fire is discovered, the fire brigade must be notified immediately to report a fire alarm.