Maintenance of chemical production recovery equipment

Safety Management System for Maintenance Work in Coking Plants 1 Formulating Maintenance Plans 1.1 Developing maintenance task plans and safety measures 1.1.1 The contents of a maintenance plan include: the name of the maintenance task, the units involved in the work, the types of workers, the methods and steps for carrying out the maintenance, as well as safety precautions. 1.1.2 The maintenance plan must include comprehensive items, detailed content, specific tasks, clear responsibilities, effective measures, and scientific methods. 1.1.3 The items covered in the maintenance plan include plans for shutting down the system, carrying out maintenance while production continues, installing or removing blind flanges, exhaust and replacement operations, entering tanks or towers, performing welding work on flammable and explosive equipment, disassembling, assembling, and lifting equipment, working at heights, as well as plans for starting up and shutting down equipment. 1.2 Procedure for formulating maintenance plans 1.2.1 For major maintenance projects, the factory prepares a maintenance task plan or a maintenance task sheet to be submitted to the company for approval. 1.2.2 For minor and medium-scale repairs, each production unit prepares a repair plan, which is then submitted to the relevant departments and the factory management for review and approval; once approved, the plan is put into effect. 2. Repair organization and management 2.1 For major repairs, a repair leadership team (or repair command team) should be established, with the factory manager in charge serving as the overall commander and chief safety officer, with members coming from the various departments involved in the repair work. 2.2 All maintenance tasks shall be carried out in accordance with the maintenance plan, with designated persons in charge for each task, and the approval procedures for such tasks must be followed. The maintenance plan is managed by the equipment department. 2.3 The person in charge of project maintenance provides unified command and coordination over the maintenance tasks under their responsibility, to ensure safety throughout the maintenance process. 2.4 In each area of the major maintenance site, the person in charge of the maintenance work and the supervisors of various work areas are responsible for ensuring safety during the maintenance, and a dedicated on-site safety officer is assigned to each area. 2.5 The person in charge of the maintenance project must personally organize the relevant technical personnel to go to the site, and provide them with instructions regarding the tasks to be carried out, as well as technical and safety guidelines, while also ensuring that all safety measures for the maintenance work are implemented ； 2.6 Dedicated personnel from the factory’s production, equipment, and safety management departments are present at the maintenance site to monitor and ensure that safety procedures are followed throughout the maintenance process. 3. Preparation for maintenance 3.1 The production area must create reliable and safe conditions for the units and departments responsible for the maintenance work, carry out all necessary preparations for such work as well as develop plans for dealing with the equipment, and ensure that appropriate safety measures are in place. 3.2 Units participating in maintenance projects must not disassemble equipment, pipelines, etc. arbitrarily if they have not followed the procedures and completed the necessary maintenance tasks as required. 3.3 In accordance with the requirements specified for the maintenance tasks, safety measures must be implemented carefully and item by item; no arbitrary changes are allowed. If there are issues in their implementation, approval from the chief commander is necessary. 3.4 The tools and equipment used for maintenance should be thoroughly inspected to ensure safety and reliability. 3.5 When maintaining transmission equipment and the electrical devices mounted on it, it is necessary to cut off the power supply (remove the power fuse). After verifying that everything is in order through two attempts to start the equipment, a \"Do Not Start\" sign should be placed on the power switch. 3.6 The maintenance unit shall inspect the hot work safety permit, the safety precautions for work inside equipment and at heights, the electrical work order, and their implementation. 3.7 The maintenance unit shall check the readiness of protective equipment and fire-fighting supplies required during the maintenance process. 4. Maintenance Safety 4.1 The key points that safety officers must understand during maintenance are: 4.1.1 Whether the power supply equipment and pipelines have been properly disconnected. 4.1.2 Whether the blind plates are removed and installed in accordance with the prescribed sequence, and whether there are any omissions or errors. 4.1.3 Check whether the cleaning and replacement inside the equipment meet the specified requirements, and whether there are any dead corners or overlooked items. 4.1.4 Whether safety protection measures (fire extinguishers, safety helmets, protective equipment, safety warning signs, on-site water sources, etc.) have been implemented item by item. 4.1.5 Check and supervise that work permits are issued in accordance with relevant regulations during the maintenance process. 4.2 Important points that maintenance personnel should master during maintenance work: 4.2.1 All maintenance activities must be carried out in strict accordance with the plant’s safety regulations for maintenance; maintenance personnel must earnestly comply with all the provisions of the safety and technical operating procedures specific to their role. 4.2.2 Maintenance personnel may proceed with work only when all procedures are in place, the approval requirements are clear, and safety measures have been implemented. 4.2.3 When maintenance personnel work on toxic and hazardous systems or carry out emergency repairs, they must be equipped with protective gear for emergency use. 4.3 Before maintenance, the person in charge of the maintenance task shall thoroughly inspect and confirm that the process treatment is satisfactory and that the blind flanges have been properly sealed. Before each task, a detailed inspection of the site is carried out as required, and work can only proceed once the specified requirements are met. 4.4 When carrying out maintenance work in flammable and explosive areas, explosion-proof equipment and tools must be used, or other explosion-proof measures must be adopted to strictly prevent the generation of sparks. 4.5 Whenever maintaining mechanical and electrical drive equipment, the power supply must be effectively disconnected, and a “Do Not Close” warning sign must be placed. When performing maintenance on equipment, containers, and pipelines, a “Do Not Start” warning sign must be placed on the valves of the material pipelines that have been shut off. 4.6 Temporary work lights used for maintenance must operate at a safe voltage. 5. Welding Operations 5.1 Safety requirements for oxygen-acetylene flame welding and cutting operations are as follows: 5.1.1 The welding tools must meet quality standards; the welding torches and control valves must be reliable, the oxygen pressure regulator must function properly, and the gas hoses must have sufficient pressure resistance and be free from damage. 5.1.2 Oxygen cylinders and acetylene cylinders must not be placed near heat sources; they must not be inverted. Acetylene cylinders must not be laid on their sides, and a residual pressure must remain in the cylinders after the gas has been used up. 5.1.3 The safety accessories of medium-pressure acetylene generators must be sensitive and reliable. 5.1.4 There should be a sufficient safety distance (≥5 meters) between acetylene cylinders and oxygen cylinders, and they must be kept at a distance of more than 10 meters from any open flames. 5.1.5 Acetylene cylinders and dissolved acetylene gas cylinders are prohibited from being placed under high-voltage power cables and pipes. 5.2 Arc welding and cutting must meet the following requirements: 5.2.1 The welding machine must be equipped with a separate power switch. 5.2.2 The secondary coil and casing of the welding machine must be properly grounded or connected to neutral for row-by-row protection, with a grounding resistance not exceeding 4 ohms. 5.2.3 The primary circuit and the secondary circuit are well insulated from each other and are easily identifiable. 5.2.4 When performing welding (electric or gas welding) in special environments and conditions, appropriate safety measures must be taken. 5.3 Welders must follow the safety procedures for welding operations. 5.4 In areas where multiple people are working together or where tasks are carried out concurrently, protective shields must be in place when performing welding tasks, to prevent the arc light from injuring others’ eyes. 5.5 For special operations such as plasma cutting and fluorine arc welding, appropriate safety protection measures shall be taken. 6. Work inside equipment: Before working inside equipment, it is necessary to take samples to analyze the concentrations of toxic and harmful substances as well as the oxygen level; work can only proceed once these tests show satisfactory results. 7. Work at heights: Personnel working at heights must strictly comply with the relevant provisions of the company’s \"Safety Regulations for Work at Heights within the Plant Area\". 8. Lifting operations: Lifting operations must comply with the relevant provisions of the company’s \"Safety Regulations for Lifting Operations within the Plant\", and a lifting plan must be prepared. Such a plan can only be carried out after it has been reviewed and approved by the department in charge of the construction project as well as safety and technical departments. 9. Completion inspection of maintenance work 9.1 After the maintenance is completed, a safety check must be carried out: 9.2 Check that tools and equipment have not been left inside the equipment or pipelines. 9.3 Remove blind plates, fences, etc. installed for maintenance purposes. The blind flange was removed, the valves operate smoothly, and the electrical instruments have been reset. 9.4 All safety facilities have returned to normal. 9.5 Conduct pressure or airtightness tests as specified, and keep records for future reference. 9.6 Ensure the site is cleaned up once work is completed and all materials are used; stack materials and tools properly to keep the roads clear. 9.7 The trial run was successful; the equipment and maintenance departments, together with the production department, conducted an inspection to confirm that everything was in order, after which the handover procedures were carried out. The production department is preparing for normal operations.

In simple terms, it is essential to know the operating conditions of the equipment; it’s best to understand the manufacturing process as well. If that’s not possible, the following points should be addressed: 1. Determine what medium flows inside the equipment. 2. Understand the function of the equipment and develop a maintenance plan. 3. For gas-related equipment, pay attention to both positive and negative pressures. 4. For equipment used in chemical processing, take into account the properties of the medium involved. (Ammonia, H2S, sulfuric acid, alkaline solutions, washing oil, crude benzene, etc. are all different.) 5. Ensure the safety of maintenance personnel and equipment.