Classification and significance of chemical equipment maintenance

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The maintenance of chemical processing equipment is classified by the timing of the maintenance: temporary shutdown maintenance and major shutdown overhauls； Classified by the amount of maintenance work: major repairs, medium repairs, and minor repairs. 　　(1) After the entire system has been in operation for a certain period of time (such as one year), it is shut down completely. The main purpose of this is to carry out comprehensive overhauls of the equipment within the system, which is known as a shutdown overhaul. The long downtime required for shutdown maintenance allows for the overhaul of a larger number of devices, but it is not possible to overhaul all of them. On one hand, this is limited by the duration of the downtime and the available maintenance resources; on the other hand, differences in device types, their quality conditions, and operating environment conditions mean that it is impossible to establish a uniform maintenance cycle for all devices. Equipment of the same type within the same system, with similar maintenance cycles, can undergo major overhauls in batches, with the timing of these overhauls for different batches staggered. During a major shutdown for maintenance, no major repairs are carried out; instead, equipment whose minor and medium-term maintenance cycles have arrived can undergo such repairs simultaneously. These major overhauls, along with the coordinated minor overhauls, constitute the shutdown overhaul plan. 　　Although this can reduce the concentration of major equipment overhauls, shutdown overhauls are often time-consuming, involve heavy tasks, and present significant challenges in terms of implementation. Therefore, temporary parking opportunities must be utilized effectively to carry out as many minor and medium repairs as possible, as well as any major repairs that may be necessary, such as for those subsystems or operational units that might be disconnected from the main system or isolated for a short period of time. However, equipment within the subsystems or operational units should also undergo synchronized and coordinated maintenance in order to reduce the number of shutdowns. 　　(2) The workload for minor and medium repairs is relatively small and the repair time is short; aside from being carried out in conjunction during shutdown major repairs, they are mainly scheduled to be done during temporary shutdowns. Chemical production requires continuous operation, but in practice, short-term shutdowns of individual subsystems or units, or temporary halts of the entire system, are inevitable. Temporary shutdowns can occur due to various reasons such as abnormal failures in key equipment, the discovery of safety-threatening issues during inspections that require immediate attention, operational mistakes by personnel in certain positions, or insufficient supply of water, electricity, and raw materials. This is the best opportunity to schedule simultaneous and coordinated minor repairs for this system or the equipment in its operational units.