How to prevent safety risks when starting the vehicle after maintenance? Please keep these 7 safety management measures

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Safety accidents resulting from the commissioning of production units after maintenance are deeply distressing and difficult to anticipate; therefore, the \"Guidelines for Safe Handling of Abnormal Conditions during the Production Process in Chemical Enterprises (Trial)\\" issued by the Emergency Management Department (Emergency Management Department [2024] No. 17) treat the commissioning of production units as abnormal conditions that require special attention. On September 7, 2023, during operation in the gasification workshop of Yiding Ecological Agriculture Development Co., Ltd., a pipeline blockage was detected; when attempts were made to address it, high-pressure gas was released, resulting in 10 deaths. On May 6, 2021, an explosion and fire accident occurred during the startup of a styrene plant at a company in Ningbo. The reason was that after the replacement of the tube bundle in the benzene tower top steam generator, the flange surfaces of the head were not tightened properly; safety conditions were not checked before starting up the equipment, and it was put into operation directly. As a result, the high-concentration benzene hydrocarbon liquid (with 98.91% benzene content) inside the head sprayed out from the flanges, leading to an explosive combustion. On February 11, 2020, a major explosion occurred at a company in Liaoning during the material feeding process, resulting in 5 deaths and 10 injuries. The direct cause was that the acetonylacetone processing unit failed to recheck and confirm the materials, and mistakenly added both acetonylacetone and chloramine into the chloramine storage tank V1428. As a result, acetonylacetone and chloramine reacted inside the tank, releasing heat; this heat accumulation eventually led to the decomposition of the materials and an explosion. On April 6, 2015, a serious explosion and fire occurred at the xylene production unit of Tenglong Aromatics (Zhangzhou) Co., Ltd., resulting in 6 injuries and direct economic losses of 94.57 million yuan. The main reason is that pressure and flow fluctuations occurred during the feed introduction operation at the start-up of the xylene plant, causing water hammer; as a result, pipe welds with quality issues broke at their weakest points. So, how can we prevent risks during the startup of the device? 1. Conduct risk identification and assessment before driving. Risk assessment must be targeted; for example, it should cover potential risks such as the implementation status of the change measures involved in this maintenance, the equipment undergoing maintenance, and the catalysts that require temperature elevation for regeneration. The sources and bases for risk identification are generally key operating steps, hazardous incidents that have occurred during previous start-ups and shutdowns, and lessons learned from other accident cases. Risk identification and assessment should involve different types of professionals, with the inclusion of experienced field operators being preferable. Based on risk identification and assessment, a driving plan is prepared and approved. A pre-start safety checklist is prepared based on the identified risks and control measures. 2. Conduct proper training for personnel and make work arrangements prior to driving. Before startup, it is necessary to conduct training for startup personnel on the startup plan, so as to fully identify the risks involved in the startup process, especially major risks and critical steps. At the same time, it is necessary to clarify the responsibilities and job requirements of personnel in various departments, especially those in the electrical and instrumentation as well as maintenance fields, so that they can address any equipment issues that arise during the commissioning phase and ensure smooth operations. 3. Ensure that the safety conditions before driving are met. Checking the safety conditions before driving is an important guarantee for driving safety. From pressure testing, purging, airtightness checks, removal and installation of blind flanges, the operating status of valves, interlock testing, to individual unit trials, the safety \"barrel theory\" tells us that even one oversight can lead to safety accidents during startup. Fill out the pre-driving safety checklist according to responsibilities and inspection results, in order to raise everyone’s awareness promptly; this is also a requirement for ensuring traceability of operations. 4. Ensure proper verification of the key steps during driving. While driving, it is essential to follow the established driving plans and procedures strictly; any mistake in certain steps can lead to safety accidents. These steps may include feeding materials, raising temperature, breaking vacuum, starting up the core equipment, adding or introducing catalysts, and drying the furnace. Operators need to be aware of the operational risks and requirements; moreover, such actions can only be carried out after confirmation by a team leader, a specialist, or the plant manager, depending on the level of risk involved. 5. Properly handle abnormal operating conditions as specified in the driving procedures. During the commissioning of production units, abnormal situations often arise, including deviations from process parameters, leaks, failures in the control circuits, even unit shutdowns and pipeline blockages. This requires us to strictly follow the abnormality handling procedures, and ensure that measures such as the handling steps, safety protections, and parking conditions are properly implemented. While driving, it is necessary to control the number of people at the production site, and to retreat to a safe state in accordance with the authorization levels for abnormal conditions as well as the specified withdrawal criteria. If an abnormal condition occurs during driving that has not been identified and for which there is no emergency procedure, the driver should immediately stop the vehicle or bring it to a safe state; there should be no hesitation, no decision to wait and see, or no attempt to try again. 6. Perform proper system optimization in the later stages of driving. In the later stages of the plant’s operation, system optimization is required. This includes whether the process parameters are within the controlled range, the operation of control loops and interlocks, the deactivation of auxiliary startup facilities such as those for temperature increase, and the thermal tightening (or cold tightening) of flanges with significant temperature rises. It is recommended to organize comprehensive inspections and information exchanges among various specialties to ensure that the production facilities are in their optimal condition. 7. Conduct a summary and improvement process after driving is completed. Summarize the experiences and shortcomings in terms of professional management and safety management during this operation. Good practices should be institutionalized, while shortcomings require root-cause analysis to develop corrective measures, ensuring further improvements in safety management for subsequent operations.