How to maintain a device when it is out of use for a long time?

Interim Provisions on the Protection and Management of Decommissioned Devices and Equipment Chapter 1 General Provisions 1. These provisions are formulated to strengthen the maintenance of decommissioned devices and equipment. 2. The Technology Development Department and the Production Operations Department shall determine the possible duration for which the equipment will be out of use ； And notify the Mechanical Equipment Department in writing. Chapter 2: Handling of Decommissioned Equipment 1. The workshop thoroughly purges all equipment, pipelines, pumps, and other individual units to remove residues and moisture. 2. Isolate the process pipelines connected to the outside world to prevent leaks, spills, cross-contamination, and freezing. Valves that are connected to the outside world should be fitted with blind flanges and closed; these blind flanges must be labeled with a “Blind Flange” sign, and a record of them should be kept along with identification of the person responsible. 3. For facilities connected to the power system, contact the relevant power department to close the supply and return system valves and install blind flanges. 4. Any leaks in valves, flanges, etc. that occur during the operation of the device must be addressed immediately to restore them to a proper condition, thereby preventing nitrogen leakage when the device is shut down and filled with nitrogen. 5. Decommissioned equipment and devices shall be marked with safety and environmental protection labels in accordance with the requirements of the Safety and Environmental Protection Department. Chapter 3: Protection and Management of Individual Equipment 1. Process equipment is not kept in standby; predictive maintenance is implemented. Plans are submitted 4 months before replacement, and the manufacturer is contacted through e-commerce 3 months in advance for production. 2. Since the equipment has been in use for some time, after it is taken out of service, it is necessary to remove corrosion products (including deposits or sludge), clean it, and dry it, so that the equipment becomes clean and free of water. In particular, it is necessary to avoid corrosion of stainless steel equipment by chloride ions and of brass by ammonia; protective measures should be taken immediately after the equipment has been treated. 3. Equipment such as towers and containers can be protected by nitrogen filling, and the nitrogen level should be replenished in a timely manner according to the situation. 4. If the equipment is out of use for more than half a year, gas-phase corrosion inhibitors can also be used for protection; this method can be applied to towers, containers, and waste heat boilers, with a typical protection period of 3–4 years. 5. For air coolers, nitrogen filling can be used for protection. 6. For cold exchange equipment, after removing the core and cleaning it dry, it is immersed in lubricating oil for protection; once removed, it is reinstalled and then protected with nitrogen. 7. The valve should be coated with grease for protection, covered promptly with thick plastic film, and undergo re-anti-corrosion treatment annually. 8. After cleaning and drying the core of the heat exchanger equipment, it is immersed in lubricating oil for protection, promptly wrapped with thick plastic film, and undergoes anti-corrosion treatment again every year. 9. The anti-corrosion paint on the outer surface must remain intact. 10. The newly purchased equipment in the e-commerce center needs to be protected, and the protection measures shall follow the provisions mentioned above. Chapter 4: Protection Management for Devices and Equipment That Are Not in Use for Prolonged Periods I. Protection of the Inner Surfaces of Process Equipment 1. For equipment that is severely corroded, high-pressure water guns should be used to remove impurities from it, and any areas on the metal surface where corrosion has caused bulging or rusting should be manually removed, in order to prevent such corrosive substances from interacting with oxygen, water, and other elements and thereby accelerating further corrosion of the equipment. 2. Drain the water remaining in the equipment’s interior; stopping operation for cleaning can result in water staying inside the equipment. After shutting down, promptly open the drainage outlets at the lowest points of the equipment and pipelines to remove the water, and use air to clear any water that remains in hidden areas along the cleaning path. 3. For equipment equipped with oil filling protection, after purging the interior of the equipment with steam, diesel should be filled in; safety issues such as leaks must be taken into consideration. 4. For equipment that cannot be filled with oil, nitrogen protection can also be used by introducing nitrogen into the system and maintaining a certain positive pressure to prevent outside air from entering. The purity of nitrogen should be maintained at over 99%, and the nitrogen pressure as well as the integrity of the system should be checked regularly. The general steps are as follows: first, use steam for purging to completely remove oils with high freezing points; then use industrial air for purging to keep the surfaces of the equipment and pipelines dry; finally, use nitrogen to purge all air from the system (at a pressure of 0). 4-0. After replacement to 5 Mpa, the inlet and outlet are sealed with valves or blind flanges, maintaining the nitrogen pressure at around 0.2 Mpa. 5. Vapor-phase corrosion inhibitors are used to protect other towers and containers within the device; within these sealed containers, the inhibitors continuously evaporate to release protective gases with high vapor pressures, which form a chemically adsorbed layer on the metal surface to prevent corrosion, thereby achieving long-term protection. Seal it promptly after filling to prevent a large amount of anti-corrosion gas from leaking, which could affect the anti-corrosion effect. It is necessary to pay attention to the different materials of the equipment, and select appropriate corrosion inhibitors accordingly. 6. Drain the water remaining in the equipment of the water system, shut down the equipment for cleaning. For equipment that can be filled with oil, use oil as a protective medium; for equipment that cannot be filled with oil, nitrogen can also be used for protection. II. Moving Equipment: To prevent deformation and sticking of the shafting in moving equipment, it is necessary to turn them regularly. For large units, this should be done once a month for no less than half an hour each time; for small pumps, it should be done once a month, with each rotation covering 180 degrees. The 2 large units are transported by oil once a month; the duration of transportation is no less than 6 hours in winter, no less than 2 hours in summer, and no less than 3 hours in spring and autumn. The moving parts of the 3 lifting equipment should be inspected once a year, with maintenance carried out as appropriate. III. Electrical and instrumentation equipment: Electrical cabinets and instrumentation cabinets should be cleaned once a year, while UPS units should be charged once per quarter. During winter, necessary anti-freezing measures should be taken to prevent damage to the power supply due to freezing. IV. Equipment exterior: The shaft shoulders of pumps, the exposed valve stems, and the steel cables of lifting equipment should be lubricated once a year. When greasing the valve stem, first open the valve fully; after greasing the threaded part of the valve stem, close the valve fully. After lubricating the steel wire rope and valve stem, wrap them promptly with thick plastic film. 2. The electrical components of outdoor lifting equipment, the valve heads of various other types of valves (such as electronically controlled valves and pneumatically controlled valves), the on-site control panels, the surface-mounted instruments, the machine body, and the associated motors are all covered with thick plastic film. 3. Based on the corrosion condition of the equipment and the outer surfaces of the steel components, take feasible measures for anti-corrosion treatment. 4 pairs of critical, precise, and valuable electrical instruments were taken back to the warehouse for secure storage. 5 The floor, equipment surfaces (or enclosures), and factory premises should be cleaned weekly. Ensure the floor is free of debris, the surfaces of equipment are virtually free of dust and oil stains, the factory premises are clean and tidy, items are arranged neatly, and waste is collected promptly. V. Equipment file management: Keep proper records of the maintenance and management of idle equipment, and classify them into equipment files at the end of each year to ensure there is a record available for reference. Chapter 5: Protection Management for Temporarily Shutdown Equipment 1. During shutdowns, assist with process and safety operations; if it is not necessary to return the materials, do so as little as possible, and isolate oxygen to protect the equipment and pipelines. 2. For devices that can be filled with oil, oil protection measures should be employed; after purging the device’s interior with steam, diesel should be poured into it, taking into account safety issues such as leaks. 3. For equipment that cannot be filled with oil, nitrogen protection can also be used by introducing nitrogen into the system and maintaining a certain positive pressure to prevent outside air from entering. 4. Drain the water remaining in the equipment of the water system, shut down the system for cleaning; for water coolers that have been in use for over a year, it is necessary to remove the core components for cleaning when they are shut down. 5. Inhibition of polythionic acid corrosion: To prevent stress corrosion cracking caused by polythionic acid in austenitic stainless steels and austenitic alloys during plant shutdowns, intermittent stops, and startup periods, the main methods include selecting appropriate metals, preventing oxygen from entering, performing surface alkali cleaning, and avoiding the formation of liquid water. 6. During shutdown of the high-temperature expansion joint, apply electric heating to maintain a temperature above the dew point. 7. After the catalytic waste heat boiler is shut down for cooling, ash removal and cleaning must be carried out immediately; after cleaning, alkali washing should be used right away for protection. The wash solution is 2 wt% Na2CO3 with a pH value greater than 9. 8. Protection of the reactor. The protection of an open reactor allows skilled workers using appropriate air breathing equipment to load and unload the catalyst inside the reactor under nitrogen protection. After unloading, the reactor should be purged with dry air, and this purging process must continue throughout the time the reactor is open. 9. On the inner surface of heating tubes made of austenitic stainless steel and austenitic alloys, if coking is not removed, the tubes must be kept dry ； When removing coke, it is necessary to ensure that the surface of the furnace tube is alkali-washed with an alkaline solution. The thermal decoking method should be used such that no condensation occurs on the furnace tube before decoking is completed; when this method is employed, alkali washing should be applied during and after the decoking process. 10. Protection for special equipment plate-type air coolers and other air coolers. After purging and neutralization cleaning during the maintenance shutdown, nitrogen protection is applied.

http://bbs.hcbbs.com/viewthread.php?tid=354122&highlight=%B3%A4%C6%DA%CD%A3 for reference

①Lubricate the valve stem, and fit a protective sleeve on the stem； ②Oiling of the control valve spool ； ③Rotating equipment: Pumps should be turned manually once a week ； Compressor: Nitrogen is filled into the reciprocating machine cylinders, while a buffer gas is used in the centrifuge (dry gas seal) ； Ammonia filling protection for co-phenyl screw compressors ； ④All control valves and flue dampers are operated regularly every half month ； ⑤The boiler system can be protected using quicklime or a gas-phase protective agent ； ⑥Stainless steel equipment in catalytic and hydrogenation units is susceptible to dew point corrosion; those equipped with steam coils need to be protected by steam during shutdown periods ； ⑦To protect the water pipelines, in principle, the recirculation water pipelines within all shutdown devices should not be stopped.

It’s just my personal opinion – it can meet the standard requirements, but it’s also quite practical. 1. The catalyst is sealed in the reactor with nitrogen, maintaining a pressure of 0. Around 2 MPA, no oxygen can be introduced, and the temperature is at room temperature. 2. We hardly move the mechanical equipment, but we check it regularly. 3. For static equipment such as towers and containers that contain materials, if the product type is not to be changed during the next operation, these materials can remain in the towers; however, before starting the next operation, these materials should be removed first before new materials are added. 4. It is better to discharge the steam condensate from the drum using nitrogen. After draining all the water, we generally ignore it – we neither fill it with nitrogen nor dry it out – and this has no impact on the next startup. 5. For instruments, ensure good waterproofing ； All power supplies at the site must be cut off, and there must be someone on duty for electrical operations ； For analytical instruments such as gas chromatography, remove the column, seal it, label it, and store it properly.

Two more points: The valves on site need to be lubricated; in our company located by the sea, corrosion is severe not only when the vehicles are parked but also while they are in use； Drain all the water from the heat exchanger, and empty the water in the circulation tank as well; otherwise it will deteriorate and bacteria will grow over time.

.5 Protection of the catalyst 1. Under no circumstances shall the temperature of the catalyst layer exceed 300°C. 2. The reduced catalyst must absolutely not come into contact with oxygen or air. 3. During the use of the catalyst, attempts should be made to avoid stopping midway. Every time the vehicle is stopped, even with passivation or nitrogen protection measures in place, it still affects the service life of the catalyst. 4. The heating and cooling of the catalyst must be carried out slowly; rapid heating and cooling are prohibited. 5. Under the conditions of meeting production capacity and yield requirements, the catalyst should be operated at low temperatures, which helps to extend its service life. 6. It is strictly prohibited to allow toxic substances such as sulfur, phosphorus, and halogen elements to enter the system, to prevent catalyst poisoning. 7. The raw materials used in the device, such as methanol, deionized water, nitrogen, and hydrogen, must meet specified requirements, and strict testing procedures must be followed. 8. If any abnormalities are detected, especially issues with the reaction system, the operation should be stopped immediately for analysis and inspection; operations can resume only after the problems have been resolved.

If you have any questions, contact President Tang at 22546831 (a member of the Haichuan Technology team); you should be able to guess who I am

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