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1. Pump risk identification: For pumps, the greatest risks during operation are leakage and overpressure, as well as associated risks such as mechanical injuries. 1) Overpressure risk: For centrifugal pumps, overpressure can occur when there is no check valve at the pump outlet or when the check valve fails, which leads to high pressure flowing back into the system. For positive displacement pumps, the main cause of overpressure is an outlet blockage or an unclosed outlet valve. The greatest risk of pump overpressure is that it may cause overpressure in the downstream pipelines and equipment, or lead to physical explosions. Classic case: At 16:14 on March 12, 2018, an explosion and fire accident occurred in the diesel hydrogenation unit of Unit 1 for oil refining at Jiujiang Petrochemical. The accident resulted in 2 deaths and 1 person suffering burns (minor injuries). The cause of the overpressure in V501 was that after the reaction feed pump P501B stopped operating due to an interlock, the pump outlet valve did not close in time; simultaneously, the check valve at the pump outlet leaked, allowing high-temperature and high-pressure fluid from the P501/B outlet to flow back into V501, resulting in overpressure and explosion in V501. Article 7.2.11 of the Code for Fire Protection Design of Petrochemical Enterprises GB50160-2008 stipulates that centrifugal combustible gas compressors and combustible liquid pumps shall be equipped with check valves on their outlet pipes. During each expert inspection, the outlet check valve of the centrifugal pump is also one of the key items to be inspected. Not all pumps necessarily need check valves; they are required in those devices where the pressure in the outlet system is high, or in those dealing with flammable gases and liquids. 2) Leakage risk: During the operation of our pumps, leakage is a common occurrence. Generally speaking, the causes of leakage include corrosion, abnormal fluctuations in the manufacturing process, incorrect material selection, and so on. As is well known, when a device operates continuously, the pump also runs for long periods of time. During this time, leaks within the device are common due to wear and tear, erosion by the material being processed, and corrosion. However, it is often such minor incidents that lead to safety accidents, or even serious disasters. For pumps, we can also use the HAZOP analysis method to conduct risk discussions. Classic case: On April 10, 2015, a leak and fire occurred in the bottom pump of the stripping tower in the hydrocracking unit of Dalian West Pacific Petrochemical Co., Ltd. A pipeline (with a diameter of 200 mm) above the bottom pump cracked, and the oil and gas inside the pipeline ignited at the site of the crack. As a result of this incident, 3 pumps, the framework above them, some instruments, and power cables were damaged by fire; one pipeline cracked, but no other equipment was damaged, and there were no casualties. The cause of the accident was: failure of the seal on the bottom pump of the stripper, resulting in leakage and fire. Through disassembly inspection of the pump, it was found that bearing damage is the main cause of rapid seal failure. During high-speed operation of the pump, severe damage to the bearings causes intense vibrations in the equipment, which leads to the rapid and simultaneous failure of the mechanical double seals and results in fluid leakage. The high temperatures generated by friction with the bearing housings can then trigger a fire. At 18:31 on August 17, 2017, a leak occurred in the 1.4 million tons per year heavy oil catalytic cracking unit at the Second Combined Workshop of CNPC Dalian Petrochemical Company, which triggered a fire. Upon investigation, the direct cause of this accident was abnormal damage to the bearing at the drive end of the feed oil pump in the distillation unit of the third catalytic unit in Dalian Petrochemical Company’s Second Combined Workshop. This led to severe vibration of the feed oil pump, resulting in multiple breaks in the sealing bellows and causing an oil leak that ignited a fire. 2. Control measures: Based on risk management, we start by focusing on the hazardous substances that are to be transported via pumps. We know that hazardous chemicals generally have characteristics such as being flammable, explosive, toxic, and harmful. So, which pumps related to such substances should we pay special attention to? 1) Liquid hydrocarbon pumps 2) Pumps containing toxic and harmful substances 3) Pumps with temperatures above their auto-ignition point. We should manage these pumps as high-risk equipment, focusing first on eliminating the risk of leaks at their source. From accident cases, we already have a pretty clear understanding of the causes of leaks; most of them are due to the failure of mechanical seals. So how can leaks in pumps be effectively controlled? We will explain this from the following points: a. Pump selection: 1) For pumps that handle toxic and harmful substances or liquid hydrocarbons, we should use leak-free pumps such as shielded pumps or magnetic drive pumps instead of ordinary centrifugal pumps. Because such media are extremely hazardous in the event of a leak, as they can easily cause poisoning and fires or explosions. 2) For pumps such as high-temperature hot oil pumps, whose operating temperature is above the auto-ignition point, shielded pumps are not suitable due to factors like high operating temperatures and high fluid viscosity; in such cases, we can make a choice based on the sealing system. High-temperature hot oil pumps, due to the high temperature of the fluid they handle, can catch fire in the event of a leak. High-temperature oil pumps are characterized by high temperatures (200–400°C), particle erosion, a tendency to coking or carbon deposition, high fluid viscosity, low inlet pressure. In the event of a leak, they can catch fire upon contact with air, leading to fires, explosions, or other secondary safety incidents; moreover, they are harmful to the surrounding environment. Based on this characteristic, the seal arrangement scheme for the high-temperature hot oil pump is PLAN02+32+53a+62. The primary seal uses diesel to flush and cool the seal surface, while the secondary seal relies on 46# lubricating oil in the seal fluid tank for cyclic flushing and cooling. The seal fluid tank is equipped with a seal oil pressure alarm switch and a liquid level alarm switch; it has a nitrogen pressure regulator at the top. Medium-pressure nitrogen at 2.0 MPa (gauge pressure) from the outside is reduced in pressure by the regulator before being used to pressurize the seal fluid tank, and the pressure after the regulator should be higher than the system’s set pressure value. If the pressure in the sealant tank is below the set value or the liquid level is below the lower limit, the pressure or level switch will issue an alarm signal, along with audible and visual alerts in the control room. This allows for quick access to information on seal failures and the ability to take emergency measures, thereby preventing such failures from developing further. b. Monitoring and detection: Online monitoring – Vibration is the main cause of seal failure; for high-risk pumps, we can equip them with online condition monitoring systems. The system integrates monitoring, diagnosis, alarm functions, and predictive maintenance, enabling better real-time control over the operation of high-temperature oil pumps. Automatic fire suppression: To prevent the spread of leaks and fires, foam sprinkler systems can be installed on high-risk equipment. In the event of a leak or fire, flame sensors connect to the automatic fire foam control system, thereby enabling integrated monitoring of flames and automatic control of the sprinkling process. Emergency shutdown: In accordance with the requirements of Sinopec Corporation’s document No. 23, \"Guidelines on Ensuring the Safe Operation of High-temperature Oil Pumps,\" electric or pneumatic gate valves should be used for the inlet and outlet valves of high-temperature oil pumps with a diameter of ≥ DN300, so as to enable rapid interruption of fluid flow in the event of an accident. At the same time, an emergency stop button is added to the DCS computer in the control room; by configuring the DCS, the motor’s emergency stop signal is sent to the switchgear in the electrical distribution room, thereby enabling emergency stop protection for the motor. Video surveillance: Video surveillance is added to all high-risk pumps, with real-time footage from the site being transmitted via cameras to the video monitors in the control room, allowing operators to monitor the operating status of these high-risk pumps directly from inside the room. c. Routine inspections: The purpose of these inspections is to prevent failures before they occur. By conducting regular checks on the equipment, potential faults can be identified in advance, measures can be taken to eliminate them, the performance of the equipment can be maintained stable, and the lifespan of its components can be extended, thereby improving the efficiency of the equipment. So how can equipment inspection be done properly? Considering the current equipment management practices at Shandong Huayang Pesticide Chemical Group Co., Ltd., here’s how routine inspections should be carried out: Establish inspection standards – these standards should originate from the actual workplace, and be developed jointly by equipment engineers and operators, with regular updates to keep them current. Secondly, the inspection contents should include checks on the basic operating conditions of the equipment, safety inspections, checks on process parameters, and inspections of areas where failures occur frequently. For each type of inspection, appropriate inspection intervals and personnel responsible for carrying out those inspections need to be determined. Conduct inspection training: To carry out inspection work effectively, it is very important to train various types of inspection personnel. Because the inspection personnel are the direct managers of the equipment, and they are key to effective equipment inspection and maintenance management. Therefore, targeted professional training must be provided for both the operators performing routine inspections and the specialized inspectors. To make them aware of the importance of implementing a inspection system, understand the significance of preventive maintenance, change their habit of performing repairs only after problems arise, grasp the essence of inspection management, and become familiar with the tasks, processes, standards, and methods involved in inspection work. They should not only receive training that enables them to carry out inspections independently but also receive practical guidance on relevant skills; only in this way can inspectors who meet the required standards be trained, thereby continuously improving the quality of inspection work. Inspection assessment: To ensure that inspection tasks are properly carried out, it is necessary to strictly implement a system for assessing equipment inspections, and to establish a regular evaluation mechanism for such inspections. Through these evaluations, those responsible can be held accountable, ensuring that responsibilities are fulfilled and that rewards and punishments are applied appropriately, thereby preventing false inspections carried out without actually being on site ； Prevent false detections caused by inaccurate judgments ； Prevent missed inspections in critical areas ； Prevent the annoying situation where identified problems never get resolved. The inspection work can be evaluated by setting three key equipment management indicators: equipment failure rate, equipment downtime rate, and equipment availability rate.