Regenerator maintenance plan

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Shutdown and maintenance plan for reformer regenerator 603-R-301 (process section) I. Reasons for shutting down the regenerator for maintenance and maintenance tasks Since July 11, 2008, the level of material in the separation hopper 603-LI0301 of the reforming unit has been dropping abnormally. On the 11th, the average measurement of the material level in hopper 603-LI0301 was around 54% ； On July 12, the level dropped to around 53% ； On the 13th, the level dropped to around 52% ； On the morning of the 14th, the level dropped to 50%, and by evening it fell to around 49% ； By 10:00 on the 15th, the level in hopper 603-LI0301 had dropped to around 46%. That is, within 3 days the level of material in the entire separation hopper decreased by about 7%, which corresponds to a reduction of approximately 250 kg in the amount of catalyst stored in the system. Yet, during the same period, the amount of catalyst dust discharged was less than 5 kg, which is an extremely abnormal phenomenon. The reason for the abnormal drop in the level of material in the separation hopper is, based on the current operational analysis, most likely wear and perforation of the Johnson screens inside the regenerator, which leads to catalyst loss. To resolve this issue, it is necessary to shut down the reforming and regeneration system, remove the catalyst from the separation hopper and the regenerator, and then open the regenerator to inspect and repair the Johnson screen. Based on the current operation of the reforming and regeneration system, the reforming and regeneration air dryer requires replacement of its desiccant, and the alkali washing system needs to be inspected; these tasks can only be carried out when the regeneration system is shut down. If the reforming regenerator is to be shut down for maintenance, and related systems also need to be worked on simultaneously, then the maintenance work on this reforming regenerator includes the following main tasks: 1. Opening the cover of the reforming regenerator 603-R-301, lifting it, and performing maintenance; related systems also need to be disassembled and reassembled as part of this process ； 2. Catalyst discharge and loading for the separator hopper and regenerator system ； 3. Catalyst cleaning inside the regenerator and in the burnout circulating air duct system ； 4. Replace the desiccant in the regenerative air dryer ； 5. Clean the regenerative alkali washing system; remove the manhole from the alkali washing tower for inspection. 6. Other maintenance tasks that require the shutdown of the regeneration system to be carried out. II. Preparatory work before shutting down the regenerator 1. Adjust the production process by reducing the severity of the reactions in the reforming unit (by lowering temperature and volume), thereby minimizing catalyst carbon deposition. At the same time, the regeneration system continues to ensure full circulation and regeneration of the catalyst, thus reducing the carbon content in the catalysts of the reaction system. This helps to prevent an excessive increase in catalyst carbon content during the period when the regeneration system is shut down while the reforming reactions continue to operate. It is recommended to reduce the temperatures of all reaction vessels to below 490°C three days before shutting down the regeneration process, so that the catalyst can undergo one cycle of regeneration under conditions of low carbon deposition ； During the shutdown of the regeneration system, the temperatures of various reactions in the reformer are reduced to 480°C or even lower, and the feed rate is lowered to around 120 t/h (85% load). 2. In accordance with the shutdown maintenance plans for the reforming and regeneration units proposed by Unit 4 of the Operations Department and the various specialized teams in the Maintenance Unit, the Mechanical Department is requested to promptly determine the specific maintenance tasks and the units responsible for them, and to carry out the necessary preparatory work. Such as the determination of the regenerator maintenance unit and the preparation of material and tool plans. 3. For the desiccant that needs to be replaced in the recycled air dryer, the procurement department should contact the manufacturer as soon as possible (Guangdong Zhaoqing Chemical Machinery Factory, dryer model ARD-Ⅱ-15/8) to determine the type and quantity of desiccant (aluminum gel with a diameter of φ3–φ5), and have it purchased and delivered to the site at the earliest possible time. Tianyu Logistics is responsible for transporting 150 empty tanks for reprocessed UOP catalysts to the site. 4. The catalyst loading and unloading unit shall prepare the loading/unloading equipment and cleaning tools, including: one crane, two catalyst loading hoppers, one catalyst loading platform, one hopper for loading at the top of the separation hopper, two forklifts, an industrial vacuum cleaner, an industrial endoscope, rainproof tarpaulins, sleepers, a soft ladder, canvas bags, a scale, low-voltage lighting, a tape measure, gas masks, as well as protective clothing, gloves, masks, etc. that the loading personnel must wear. III. Steps for shutting down the regenerator for maintenance The maintenance work on the entire reforming regenerator system is carried out in several stages: shutting down the catalyst regeneration system, removing the catalyst from the separation hopper and the regenerator, performing maintenance on the regenerator system (including maintenance of the regenerator itself, replacing the adsorbent in the regenerative air dryer and opening manholes in the alkali scrubber for inspection, as well as other maintenance tasks), loading catalyst back into the separation hopper and the regenerator, and restarting the catalyst regeneration system. (1) Shutdown of the catalyst regeneration system: 1. Stop catalyst circulation and chlorine injection for regeneration. 1) Perform a manual thermal shutdown for regeneration by setting the catalyst flow switch to “OFF”. Keep the regenerator charred until the peak temperature of the regenerator bed drops below 500°C, at which point almost no oxygen is consumed. 2) Open the nitrogen valve XV0503, and close the air valve XV0501 as well as the lower air valve XV0502. 3) Manually close the residual air release valve AV0601, and set the dry gas flow rate FIC0503 to 500 Nm3/h. 4) Shut off the upstream valve of the air valve XV0501 to disconnect the air pipeline. 5) Close the chlorine injection valve XV0702 as well as the upstream and downstream shut-off valves; simultaneously stop the N2 purging and heat tracing steam in the regeneration chlorine injection pipeline, and close the relevant valves of the regeneration chlorine injection pump system. 2. Regenerator cooling: 1) Manually reduce the temperatures of electric heaters EH303 and EH304 gradually at a rate of 30–40°C/h. 2) When the inlet temperature of the regeneration fan drops to 250°C, switch the regeneration fan K301 to low-speed operation. 3) When the temperature control output of the electric heaters EH303 and EH304 is zero, the heaters stop operating. 3. Stop the alkali washing system: When the temperature of the regenerator bed is below 400°C, cease the injection of alkali; stop the alkali injection pump P303 and close the outlet valve ； When the temperature of the regenerator bed is below 300°C, increase the amount of circulating alkaline solution added, and at the same time increase the discharge volume from the waste alkali line ； Observe the turbidity of the discharged liquid; when the liquid is clear, close the waste alkali valve, stop adding water, shut down the alkali solution circulation pump P301, and close the inlet and outlet valves ； Open the drain valve in D309 to drain all the water. 4. Stop the fans of the regeneration system: 1) After manual thermal shutdown of regeneration, manually close the upper and lower isolation systems and maintain N2 purging. 2) Gradually open the FIC0403 to control the air flow during the startup phase, and stop the lifting fan K304 ； Manually close the pressure-controlled nitrogen valve PDV0402A of the separation hopper, and stop the dust removal fan K303. 3) Continue to feed N2 into the regenerator via EH304, and maintain the flow rate at FIC0503 at 500 Nm3/h, until the temperatures at all points in the regenerator are below 60°C; then stop the regeneration fan K301 and the air-cooling fan K302 ； Close the N2 valve feeding into the regenerator and install a blind flange. 4) Set the regenerator start/stop button to the “STOP” position. 5. Ensure proper isolation of the reformation and regeneration sections. Close valves V and B at the bottom of Reforming Unit 4; install a temporary blind plate on the lower flange of isolation valve XV0208 ； Close valves V and B at the bottom of the regenerator; remove the 8-shaped blind plate from the flange below valve B ； The 8-shaped blind plate on the pipeline connecting the top of the nitrogen-sealed tank to the catalyst feeding pipeline was removed. 6. The separation hopper and regenerator system are depressurized to atmospheric pressure. (II) Separating the hopper and the regenerator to unload the catalyst: 1. The specific plan for unloading the catalyst is formulated and implemented by the unit responsible for catalyst handling. 2. The catalyst is discharged through the online catalyst removal pipe located between the regenerator and the nitrogen seal tank, then placed in barrels on the ground and sealed, before being stored in a centralized area with proper protection against rain and moisture. The catalyst barrels must be numbered and registered in the order of removal; in particular, the white and black catalysts must be properly labeled and stored separately so that they can be reinstalled in reverse order when loading. 3. To accelerate the maintenance process, catalyst removal can begin when the temperature at various points in the regenerator is below 200°C. However, it is necessary to maintain the flow of cooling N2 at the lower part of the regenerator and control the rate of catalyst removal to ensure that the catalyst removed is at room temperature. 4. After the catalyst has been unloaded, the radiation source of the level gauge in the separation hopper must be turned off, and the top of the separation hopper should be inspected to ensure that all catalyst has been removed. Any residual catalyst in the hopper should be cleaned up using an industrial vacuum cleaner. (III) Inspection of the front cover of the regenerator 1. The specific inspection plan for the regenerator is formulated and implemented by the maintenance unit. 2. Once the catalyst has been unloaded from the separation hopper and the regenerator, remove the catalyst transfer pipe that connects the separation hopper to the regenerator and label it appropriately ； Before removing the regenerator, all thermocouples in the bed layer must be taken out and labeled ； The ends of the removed catalyst feed pipes, as well as the catalyst feed pipe openings on the regenerator cover, must be sealed with transparent tape to prevent debris from falling in and causing blockages. 3. The maintenance unit removes the elbow at the top outlet of the regenerator, opens the regenerator cover, and carries out operations such as lifting and maintenance. 4. The catalyst handling unit shall use an industrial endoscope to inspect the space between the regenerator’s Johnson outer mesh and the vessel wall, as well as the burnt-catalyst recirculation air duct system; if catalyst is present, it must be cleaned thoroughly using an industrial vacuum cleaner. 5. During the maintenance work on the regenerator, it is necessary to take measures to prevent rain and moisture, so as to avoid water ingress and moisture accumulation in the regenerator system. 6. After the inspection and repair of the regenerator Johnson net are completed, the maintenance team reinstalls all the equipment, pipelines, and instruments in the regenerator system back to their original state, to ensure that the catalyst feed pipe from the separation hopper to the regenerator remains unobstructed. 7. Temporarily seal the top of the separation hopper, ensure airtightness of the separation hopper and regenerator system, and only after verification can catalyst loading proceed. (IV) Replacement of the regenerative air dryer adsorbent, inspection by opening manholes in the alkali scrubber tower, and other maintenance tasks. 1. These maintenance tasks are carried out simultaneously with the maintenance of the regenerator, with the specific implementation plans being prepared by each maintenance unit. 2. The desiccant for the regenerative air dryer is provided by the manufacturer and must be replaced in its entirety; proper measures should be taken to protect it from rain and moisture during replacement. During the replacement of the filter, the instruments perform joint calibration of some related instruments of the dryer (controllers, programmable valves). 3. After shutting down, the regenerative alkali washing system is first cleaned with clean water, followed by disassembling the manhole to inspect the alkali washing tower. 4. Other maintenance tasks that require the shutdown of the regeneration system include the maintenance of the regeneration fan and the calibration of certain regeneration instruments; all of these must be completed simultaneously with the maintenance of the regenerator. After the regenerative electric heater is shut down, care should be taken to provide moisture protection. (5) Loading catalyst into the separation hopper and regenerator: 1. The specific plan for catalyst loading is formulated and implemented by the catalyst handling unit. 2. After the separation hopper and regenerator system have passed the airtightness test, catalyst loading can be carried out. 3. Prepare the loading tool for inserting the catalyst through the flange at the top outlet of the separation hopper D-303, and ensure that the manual V-valve and B-valve below the regenerator R-301 are closed ； The 8-shaped blind plate under the B valve flange has fallen through ； The 8-shaped blind plate connecting the top of the nitrogen-sealed tank to the catalyst feeding pipeline became loose. 4. Based on the catalyst barrel numbers, and in the order of installing the white catalyst first followed by the black catalyst, the catalyst is fed into the system from the top outlet flange of the separation hopper D-303, ensuring that it flows into the regenerator R-301; records of the catalyst filling process must be kept. 5. When loading the catalyst, control the speed properly and take measures to protect it from rain and moisture, in order to prevent loss or dampness of the catalyst. 6. After the catalyst has been loaded, promptly reinstall the flange cover on the top outlet of separator hopper D-303. The separation hopper and regenerator system are filled with N2 to 0.35 MPa to ensure gas-tightness; once this is verified, the system is purged with N2 to prepare for switching over to the regeneration mode. (VI) Commissioning of the catalyst regeneration system: 1. All maintenance work on the reforming regeneration system as well as the catalyst loading have been completed. Once the system has passed the N2 airtightness test, the reforming catalyst regeneration system is commissioned. 2. For a detailed startup plan for the regeneration system, refer to the operating procedures. The main sequence of key steps is as follows: pressurize the system and start the fans to establish circulation; increase the temperature in the regenerator system; get the alkali washing system up and running properly; establish circulation of the catalyst in the system; regenerate the catalyst through black burning; and switch from black burning to white burning of the catalyst. 3. During the cyclic heating process of the regenerator system, the operating unit Qilu Beiyue should promptly carry out thermal tightening of the bolts in high-temperature areas to prevent leaks. IV. Safety Precautions and Maintenance Guidelines 1. All operators and personnel from maintenance teams must study the plan carefully and carry out their tasks and operations in accordance with it. 2. The removal and loading of catalysts, the maintenance of regenerators, and the replacement of desiccants should preferably be carried out on sunny days; at the same time, it is essential to take measures to prevent water and moisture damage. 3. Unit 4 of the Hainan Refining and Chemicals Operations Department, as well as the Catalyst Loading and Unloading Company, have designated specific personnel to be responsible for the loading, unloading, transportation, measurement, and management of reforming catalysts. They keep records of the number of barrels used for unloading and loading catalysts, as well as their weights, in order to verify the amount loaded and for archiving purposes. Keep records for the replacement of desiccants in accordance with the catalyst loading procedures. Reformation catalysts are precious metal catalysts, and any spillage must be strictly avoided during handling. 4. The radiation level gauge in the reprocessing and separation hopper shall be turned off and locked by the instrumentation department after the catalyst has been unloaded; it can be put into use only after the catalyst loading is completed ； To ensure safety, no one is allowed to enter the separation hopper ； In cases where entry is necessary under special circumstances, one must wear appropriate radiation protection clothing, obtain an approval form for working inside the container, and take all necessary safety measures before entering. 5. The shipping unit, Qilu Beiyue, shall work together with Unit 4 of the Operations Department to carry out the isolation of the equipment; isolation blind plates shall be installed as required, and these plates shall be removed only after the construction is completed ； Special attention should be paid to the nitrogen lines connected to the system, which must be isolated using blind flanges. 6. During maintenance, when it is necessary to enter the regenerator or caustic scrubber for inspection, preparations must be made before entering the equipment. Unit 4 must coordinate with the laboratory to take samples every 4 hours in order to analyze the oxygen concentration inside the containers (the oxygen level must be >20%; otherwise, an air respirator and appropriate mask must be worn). Qilu Beiyue must install temporary industrial air supply pipelines as required, so as to ensure ventilation when needed. The mechanical department and the maintenance unit are responsible for entering the container via the rope ladder, checking to ensure that the bindings are secure, verifying that the safety lighting fixtures and wires meet electrical safety requirements, and inspecting to confirm that the ventilation masks and ducts are in good condition. Personnel entering the container must obtain a permit before going in ； All items brought in must be registered one by one to prevent debris from remaining inside ； There must be a dedicated person on site to supervise, and a reliable means of communication must exist between the supervisor and the people inside the container. At the same time, those outside the container need to be able to take timely safety measures to ensure the safety of the personnel working inside. 7. After the completion of all maintenance tasks, the Operations Department, the Mechanical Department, and the maintenance units shall organize a joint verification to prevent the occurrence of issues that do not meet the requirements. When lifting the regenerator head and central tube, special care must be taken to prevent damage caused by collisions. 8. In the event of any accident, all units must promptly report to the Operation Department, Mobile Operations Department, and Safety and Environmental Protection Department of Hainan Refining & Chemical Co., Ltd., and take prompt and appropriate actions to prevent the accident from spreading. V. Tasks Requiring Coordination 1. Drawing on the experience of handling similar units, the reforming unit needs to reduce the severity of the reaction conditions in order to minimize catalyst carbon deposition; thereafter, the regenerator must be taken out of service for maintenance. The maintenance time is approximately 3 to 6 days. For this occasion, the total time required for taking the reforming regenerator out of service for maintenance is estimated to be 6 days (including the time needed to shut it down and restart it). The Maintenance Department and the units responsible for various maintenance tasks need to make comprehensive arrangements for the relevant maintenance plans as well as the allocation of personnel and resources, in accordance with the total maintenance time. They must also coordinate with the Operations Department and Unit 4. At the same time, efforts should be made to speed up the progress during the maintenance process in order to reduce the overall maintenance time. It is required to carry out emergency repairs using the equipment, with the maintenance unit working continuously 24 hours a day. 2. Given that the reforming reaction section requires cooling operations before and after the shutdown for maintenance of the reforming regenerator, the total duration may reach 15 days. During this period, the octane number of the reformate gasoline will be low, which will have a significant impact on the production of high-octane gasoline throughout the plant. Additionally, factors such as hydrogen balance and energy consumption will also be affected; therefore, the Operations Department and the Planning Department should consider these aspects comprehensively ； Meanwhile, during the shutdown for maintenance of the reforming regenerator, in order to further reduce carbon deposition on the reforming catalyst and lower naphtha inventory, it is recommended that the final boiling point of the naphtha supplied from various upstream units be kept below 160°C. 3. Given the difficulty and complexity of maintaining the Johnson network, and also in order to determine the causes of equipment damage and identify preventive measures, it is recommended to invite technicians from the manufacturer and installer of regenerator equipment (Lanshi), equipment experts from design institutes (\"Prohibited content; please delete\"), as well as equipment technicians with experience in maintaining similar installations in China (such as the Shanghai Gaqiao reforming unit) to oversee the maintenance work on site. VI. Appendices
Table 1: Schedule for Downtime for Maintenance Work
| Sequence | Downtime Phase | Estimated Duration | Scheduling Plan | Remarks |
|----------|----------------|--------------------|-----------------|---------|
| 1 | Catalyst regeneration system shutdown | 12 hours | 0–12 hours on the first day | |
| 2 | Removal of catalyst from separation hopper and regenerator | 6 hours | 9–15 hours on the first day | |
| 3 | Maintenance of the regenerator system | 96 hours | From 15 hours on the first day to 15 hours on the fifth day; efforts to minimize this time | |
| 4 | Replacement of adsorbent in the regenerative air dryer | 8 hours | 9–17 hours on the second day | |
| 5 | Cleaning of the alkali scrubber system and inspection via manholes | 32 hours | 9 hours on the second day to 17 hours on the third day | |
| 6 | Other maintenance tasks | 72 hours | From 2 pm on the first day to 2 pm on the fourth day | |
| 7 | Loading of catalyst into the separation hopper and regenerator | 4 hours | 4–8 pm on the fifth day | |
| 8 | Restart of the catalyst regeneration system | 16 hours | 0–4 pm on the sixth day | |

Table 2: List of Blind Flanges for Downtime Maintenance
| Sequence | Location of Blind Flange | Pipe Diameter | Location for Maintenance | Location for Resuming Operation |
|----------|--------------------------|---------------|--------------------------|----------------------------------|
| 1 | Front flange of N2 valve XV0503 at the bottom of the regenerator | DN40 | Blind | Remove |
| 2 | Lower flange of isolation valve XV0208 | DN100 | Blind | Remove |
| 3 | Lower flange of valve B at the bottom of the regenerator | DN100 | Blind | Keep open |
| 4 | Pipeline connecting the top of the nitrogen seal tank to the catalyst feeding pipeline | DN25 | Blind | Keep open |
| 5 | Front flange of regenerative air valve XV0501 | DN80 | Blind | Remove |
| 6 | Front flanges of chlorine injection nozzles in the regenerator (2 pieces) | DN80 | Blind | Remove |