Commissioning of the Hydrofinishing Unit (II)

Device airtightness I. Purpose of airtightness Testing: Airtightness testing is carried out in stages using nitrogen to identify leak points, check the integrity of the system (including internal leaks in valves), eliminate potential hazards, and ensure smooth commissioning of the device as well as its long-term operation. II. Conditions for airtightness 1. The installation and commissioning of the compressor have been completed. 2. The purging and flushing of the device have been completed, and the flanges, orifice plates, control valves, etc., that were removed during purging have been restored to their original state. III. Preparation for airtightness 1. Contact the dispatch team to prepare sufficient nitrogen (low-pressure nitrogen, high-pressure nitrogen). 2. Set up a temporary scaffold for checking airtightness. 3. Prepare airtight testing equipment (soapy water, airtight spray bottle, chalk, small bucket), a standard pressure gauge, an airtightness test record sheet, etc. 4. Shut off valves that are not related to airtightness or install blind flanges, adjust the airtight process (including the wiring for various instruments: make adjustments in accordance with the normal operating procedures), and verify it through inspection. IV. Methods for ensuring airtightness: Areas to be inspected for airtightness include all flange seals, each static sealing point of valves (manual valves and control valves), the interfaces of various instruments (for temperature, pressure, flow), the outlet of drain valves, all pipe caps and blind covers, all exposed welds, the dynamic sealing points of moving equipment, and the final valve through which the system is connected to other systems. When the system pressure rises to the predetermined level, stop increasing the pressure and conduct an inspection using the following method: 1. When the leakage is severe, there will be a hissing sound at the leak site. 2. When soap water is applied to the test point, if bubbles appear, it indicates a leak at that location. 3. When the system is subjected to constant-pressure airtightness testing, if the pressure drop exceeds the specified value within the given time, it indicates that there is a leak somewhere. V. Airtightness standard: Airtightness is considered satisfactory if no bubbles appear when testing with soapy water, with pressure drop observed as a reference. Nitrogen airtightness process table: System pressure, Pressure increase rate, Constant-pressure time, Allowable pressure drop. 1.0 MPa, 1.0 MPa/h, 2 hours, 0.05 MPa; 2.0 MPa, 1.0 MPa/h, 2 hours, 0.05 MPa; 3.0 MPa, 1.0 MPa/h, 2 hours, 0.05 MPa; 4.0 MPa, 1.0 MPa/h, 8 hours, 0.16 MPa; 6.0 MPa, 1.0 MPa/h, 8 hours, 0.3 MPa; 7.0 MPa, 1.0 MPa/h, 8 hours, 0.35 MPa. VI. Airtightness of the reaction system: 1. Airtightness procedure: Gas supply point: Nitrogen line at the outlet of the new hydrogen generator; Venting point: High-point vent in the liquid separation tank before the circulation pump. 2. Airtightness testing method: (1) Close all vent valves, adjust the pressure testing procedure, fill with N2 to 0.5 MPa, then use soapy water to detect leakage points and address them. After the 0.5MPa pressure test is successful, replace the high-pressure gauge with a vacuum gauge, and close the manual valves on all other pressure gauges. Evacuate the reaction system to 0.017 MPa(A). Break the vacuum with nitrogen to raise the pressure to 0.1~0.2 MPa(G). After evacuating the reaction system to 0.017 MPa(A) again, the vacuum was broken with nitrogen to raise the pressure to 0.5 MPa; once the compressor passed the qualification tests, it was integrated into the system. (2) Analyze the oxygen content in the system; the acceptable standard for oxygen content is that, in two consecutive samples taken at intervals of ≥15 minutes, the oxygen content in each sample is ≤0.5% (by volume). (3) After the oxygen content analysis is satisfactory, 2.5 MPa of nitrogen is introduced at the K102 outlet; the pressure is increased gradually until it reaches 1.0 MPa. The system is held at this pressure for 2 hours to conduct a leak test, with a permissible pressure drop of 0.05 MPa. If the test is successful, the process proceeds to the next stage ； (4) Raise the system pressure to 2.0 MPa at a rate of 1.0 MPa/h, maintain this pressure for 2 hours to conduct a airtightness test; a pressure drop of 0.05 MPa is allowed. Once the test is successful, proceed to the next stage ； (5) Contact the dispatch team to supply nitrogen to the new hydrogen generator; start the generator and raise the system pressure to 3.0 MPa at a rate of 1.0 MPa/h. Maintain this pressure for 2 hours to check the system’s airtightness, allowing a pressure drop of 0.05 MPa ； (6) Raise the system pressure to 4.0 MPa at a rate of 1.0 MPa/h, and maintain this pressure for 8 hours to conduct a airtightness test; a pressure drop of 0.16 MPa is allowed. Once the test is successful, proceed to the next stage ； (7) Raise the system pressure to 6.0 MPa at a rate of 1.0 MPa/h, and maintain this pressure for 8 hours to check the airtightness of the hydrogen-related system; a pressure drop of 0.3 MPa is acceptable ； After passing the inspection, proceed to the next stage ； (8) Raise the system pressure to 7.0 MPa at a rate of 1.0 MPa/h, maintain this pressure for 8 hours to check the airtightness of the hydrogen-related systems; a pressure drop of 0.35 MPa is allowed ； After passing the inspection, if there are any issues during the airtightness test, they should be resolved promptly, after which the airtightness test shall be carried out again following the aforementioned steps until no problems remain. After passing the inspection, conduct an emergency pressure relief test. VII. Test of Emergency Pressure Relief System 1. Purpose (1) To actually measure whether the installed orifice plate meets the pressure relief requirement of 0.7 MPa/min. (2) Check whether the flare system can be used properly. (3) Check whether the logic and operation of the self-protection interlock system are accurate. 2. Test conditions (1) The reaction system is airtight up to 7.0 MPa. (2) The new hydrogen machine is operating normally. (3) The torch line is now operational. (4) The interlocks and instruments have been calibrated and are in operation. 3. Test operation steps: (1) Activate the emergency pressure relief valve to start pressure release; record various parameters every 30 seconds, and check the following: A. Whether the valve open indicator light on the control panel is on, and whether the valve close indicator light is off. B. Check whether the interlock valve for the main burner of the reaction furnace operates. C. Has the interlock for the feed pump operated electrically? D. Whether the reciprocating machine is in a “zero load” state during operation. (2) The reaction system is depressurized to 3.0 MPa. VIII. Precautions for gas tightness in hydrogen-related systems: 1. Strengthen monitoring of the compressor outlet temperature to prevent operation beyond its rated capacity due to the high density of nitrogen ； 2. During the airtightness testing, the part of the water injection system that is connected to the hydrogen-handling system is tested for airtightness together with it. 3. In the event of a leak, it must be recorded promptly and reported to the workshop; the pressure should be reduced to a safe level before proceeding to increase it again. It is strictly prohibited to attempt to repair the leak while the system is under pressure. 4. After the high-pressure system with 2.5 MPa nitrogen has passed the airtightness test, nitrogen is introduced to the low-pressure system for airtightness testing. 5. When the high-pressure system is airtight, all devices connected to it must have their shut-off valves closed, and drain valves or vent valves for high points must be opened. Special attention should be paid to changes in low-pressure levels to prevent damage to the equipment due to pressure surges. 6. When airtight, the safety valves of each container are activated, and the venting process is initiated. Control the pressure increase rate to prevent leaks from occurring too quickly. IX. Airtightness of the fractionation system. This operation is carried out simultaneously with the airtightness test of the reaction system. 1. Preparatory work before testing for airtightness: (1) The pipeline purging and flushing have been completed, and any water remaining in the system has been removed. (2) All valves in the system and all vents have been closed. (3) The pressure gauge has been inspected and is in good condition, meeting the airtightness requirements. (4) Soap water, a small bucket, and an airtight pot for airtight testing are all ready. (5) The instrumentation system is in good condition and operational. 2. Airtightness testing: (1) Airtightness testing of the low-pressure system. The airtightness pressure is 2.4 MPa; the pressure is maintained at this level for 8 hours, and a leakage rate of ≤0.02 MPa is considered acceptable. Thoroughly check for leaks at all flanges, valves, pressure transfer pipes, level gauges, pressure gauges, etc. Venting points: On-site venting at the top of the low-pressure tank. (2) Airtightness of the distillation tower system: The airtightness pressure is 0.2 MPa; the control pressure is also 0.2 MPa. The system must be kept under pressure for 8 hours, and a leakage rate of ≤0.01 MPa is considered acceptable. Each stage requires strict inspection of the items to be checked. 3. Precautions for airtightness: (1) Follow unified command during the airtightness process. (2) Prepare the airtightness record form. (3) Strictly control the pressure; overpressure is strictly prohibited. X. Airtightness of the fuel gas system: The airtightness test of the fuel gas system is carried out before heating up the equipment. 1. Preparation work: (1) Contact the dispatch team to prepare the fuel gas lines for the airtightness test. (2) The valve on the fuel gas line leading to the device is closed, the vent valve is closed, and both valves on the steam line are closed. (3) The safety valve is activated, and the vent valve is closed. (4) Both valves in front of all burners and permanent lights are closed ； All vent valves in the fuel gas system are closed. 2. Airtightness (1) Process steps: Supply point: Nitrogen in the fuel gas zone; Vent point: Vent at the highest point of the furnace’s fuel gas pipeline. A. Nitrogen is introduced into the fuel gas system, with a pressure of 0.4 MPa in that system ； B. Maintain constant pressure for 2 hours to check the airtightness of the fuel gas system ； C. If any items are missing, address them promptly and repeat the above steps. 3. Precautions (1) Close all vent valves ； Carefully check the process before airtight sealing. (2) Ensure airtightness to prevent overpressure, with the pressure controlled at 0.4 MPa.

“System airtightness: The purpose of system airtightness testing is to conduct pressure and leakage tests on the sealing points of the reaction system, to check the sealing condition of flanges and valves as well as that of the instruments, in order to identify any issues present in the system as early as possible. These include: 1. Airtightness of nitrogen in the reaction system; 2. Drying of the reaction system. When carrying out these two steps, one thing that must be taken into account is the pressure in the system! If following the ‘5. Airtightness standard: Airtightness is checked using soapy water; no bubbles should appear, and the pressure drop is observed as a reference.’ Nitrogen airtightness process table: System pressure, Pressure increase rate, Constant-pressure time, Allowable pressure drop – 1.0 MPa, 1.0 MPa/h, 2 hours, 0.05 MPa; 2.0 MPa, 1.0 MPa/h, 2 hours, 0.05 MPa; 3.0 MPa, 1.0 MPa/h, 2 hours, 0.05 MPa; 4.0 MPa, 1.0 MPa/h, 8 hours, 0.16 MPa; 6.0 MPa, 1.0 MPa/h, 8 hours, 0.3 MPa; 7.0 MPa, 1.0 MPa/h, 8 hours, 0.35 MPa. This is carried out in steps, but this is only an ideal scenario – in reality, the target pressure of 7.0 MPa cannot be achieved; the maximum pressure reached will be around 3.0 MPa, as the outlet temperature of the cyclohydrogen compressor exceeds its design value at that point.

General steps: 1. Comprehensive inspection 2. Purging 3. Leak testing 4. Heating the furnace 5. Loading the catalyst 6. Pretreatment of the catalyst 7. Starting up with oil introduction

I. Confirmation of conditions prior to plant startup 1. Startup conditions 1) All tasks for shutting down the plant and addressing deficiencies have been completed. 2) The pipelines and equipment that were disassembled as part of the maintenance and defect correction work have been reinstalled; pressure testing is complete, and the system is ready for operation ； 3) Confirm that the pumps involved in the maintenance have been fully repaired and are ready for power supply ； 4) Confirm that the hydrogen supply unit is operating properly and can provide an adequate supply of hydrogen ； 5) Confirm that the tank area is operating normally and can provide sufficient raw materials ； 6) Confirm that the heating furnace nozzles have been cleaned, all metal hoses have been returned to their proper positions, and the conditions for ignition are met ； 7) Confirm that the DCS, SIS systems, and on-site instruments are capable of operating in standby mode properly ； 8) The change projects carried out during the shutdown period have been explained to the operators, and it has been confirmed that they have understood them. 2. Preparation work 1) Have an adequate supply of qualified diesel fuel suitable for starting up the distillation process ； 2) Three types of chemicals (corrosion inhibitor, scale inhibitor, trisodium phosphate, etc.) are available in sufficient quantities ； 3) Install safety valves on all systems such as reaction and distillation systems ； II. Oil introduction and transportation in the plant’s distillation system 1. Preparation work 1) Carry out oil introduction and transportation for the distillation system 1 day in advance. 2) Contact the production scheduling and storage and transportation department to prepare diesel and secure all necessary materials for starting up operations. 3) All towers and tanks in the distillation system have been successfully purged with nitrogen. 4) Contact the laboratory workshop to prepare for sampling and conduct analytical testing. 5) Ensure that all low-point drains in the process are closed, activate the safety valves related to the distillation system, and turn on the associated heat tracing. 6) Check the readiness of the steam generator; it can be put into operation once the distillation system starts its hot oil circulation. 2. Fractionation oil introduction and oil transportation 1) Drain any remaining water. 2) System nitrogen displacement: Nitrogen is pressurized to 0.3 Mpa, and a pressure control valve is activated. 3) Adjust the oil padding process and apply oil padding. 4) Establish a short-cycle distillation process. 5) Implement a hot oil circulation for heating during distillation. 6) Adjust the distillation operations. III. Commissioning of the plant’s reaction system 1. Preparation work 1) Ensure that the pressure in the reaction system remains positive throughout the shutdown and maintenance period. 2) Confirm that the maintenance work on the cyclic hydrogen compressor is complete and it can be ready for use as a backup. 2. Commissioning of the reaction system: 1) Introduce low-pressure nitrogen to purge the system with nitrogen; after 3 purges, the oxygen content in the system is analyzed to be below 0.5%. 2) Introduce fresh hydrogen to the hydroprocessing unit to pressurize the fresh hydrogen machine system. 3) When the pressure in the new hydrogen machine system is higher than that in the reaction system, open the outlet valve of the new hydrogen compressor to pressurize the reaction system. 4) When the pressure of the new hydrogen machine system is in balance with that of the reaction system, close the outlet valve of the new hydrogen compressor. 5) Establish a hydrogen circulation in the reaction system. 6) The hydrogen sulfide level in the recycle gas of the reaction system is greater than 10,000 PPM. 7) Heating of the furnace: Ignition is carried out to start heating, with the temperature at the reactor inlet being increased at a rate of 15–20°C/h, gradually raising the reaction temperature to 200°C. The temperature at the reactor inlet is maintained constant. Under the heating effect of the circulating hydrogen, the temperature at the reactor outlet is gradually raised to 135°C; once this temperature is reached, the pressure in the reaction system is increased further to 6.0 MPA. Precautions: 1) For the reactor heating time, enable air cooling to maintain the inlet temperature of the cold high-boiling fraction within the range of 40–50°C. 2) Before oil is introduced into the reaction system, the temperature at the reactor inlet must be maintained at no more than 260°C, and the temperature in each layer of the reactor must also not exceed 260°C. 3) Due to volume expansion upon fuel injection, fuel is supplied once the pressure in the reaction system rises to the operating pressure; the number of burners in the reaction furnace should be increased as soon as possible after fuel injection. IV. Switching of Feed Oil 1. Conditions for Switching Feed Oil 1) Process Conditions of the Reaction System Feed tank pressure: 0.1 MPa Reactor inlet temperature: 260–270°C High-pressure section pressure: 6.0±0.02 MPa High-pressure section temperature: ≤45°C Circulating hydrogen volume: 100,000–120,000 NM3 2) Process Conditions of the Distillation System Stripping tower Feed temperature: 250±2°C Top pressure of the tower: 0.35±0.05 MPa Liquid level at the bottom of the tower: 60–80% Reflux ratio: Full reflux Top temperature of the tower: 235±5°C Bottom temperature of the tower: 226±5°C Steam volume for stripping: 2.0–4.0 t/h Fractionation tower Feed temperature: 370±5°C Bottom temperature of the tower: 360±5°C Top temperature of the tower: 130±5°C Pressure in the reflux tank: 0.03 MPa Liquid level: 60–80% Steam volume for stripping: 3.0–5.0 t/h 2. Preparation Work 1) Contact the dispatch team to ensure an adequate supply of straight diesel (the raw material for refined grade 3 usually contains secondary diesel; coordinate with the central dispatch team). 2) Collusion process: 3) Contact the scheduler to send qualified raw materials to the unit and direct them to in front of the valve ； 4) The scale inhibitor pump is operating properly; the level of liquid in the scale inhibitor tank is sufficient, and it is in standby mode. 5) 2 hours before feeding, start the scale inhibitor pump to add scale inhibitor to the crude oil, with the dosage controlled at 210 Kg/h. 6) 2 hours before feeding, start the corrosion inhibitor pump to inject corrosion inhibitor into the vapor line. Maintain the level of each container between 40% and 60%. 9.4 Oil feeding to the reaction system 1) Conditions for oil feeding: The hot oil circulation in the distillation system is operating normally, and dehydration is complete ； The pressure in the reaction system is 6.0 MPa, and the temperature at the reactor inlet rises to 260°C and remains constant. 2) Before feeding oil into the system, use the cold low-pressure nitrogen supply line to reduce the pressure in the hot and cold low-pressure separators to around 0.5 Mpa, and activate the control system for the cold low-pressure section by setting the pressure at 1.5 Mpa ； The torch was sent out via the rear route, and the cut-off valve for low-pressure gas feeding to hydrocracking was closed. 3) Install an automatic backwash filter and discharge the diesel oil contained within it into the waste oil tank. 4) Start the feed pump to introduce oil into the reaction system. 5) The initial feed rate is 20–30 t/h (in principle, this does not affect the normal operation of the refining unit). When the crude diesel comes into contact with the catalyst and is saturated, a certain temperature rise occurs; once this temperature wave has passed through the catalyst bed, the burners of the heating furnace are adjusted to maintain a stable temperature at the inlet. 6) After adding straight-run diesel to the reaction system, it is necessary to closely monitor the temperature changes in the catalyst bed inside the reactor, ensuring that the temperature rise in any single bed does not exceed 20°C. If the temperature rise exceeds 20°C before the catalyst bed is fully wetted, the reactor inlet temperature can be appropriately reduced. 7) Once the temperatures at the reaction inlet and in the bed are stable, increase the processing capacity at a rate of 5–10 T/H, following the principle of first increasing the volume and then raising the temperature. During the process of increasing the system capacity, the reactor inlet temperature remained stable at 260–280°C. 8) Switch the raw material and adjust the operation. 9) Start the water injection pump to fill the system with softened water. 10) After the parameters are adjusted and the system remains stable for 2 hours, contact the laboratory for sampling and analysis; once the results are satisfactory, contact the dispatch team to route the product through the qualified production line. 11) Once the product meets the quality standards, adjust the processing volume according to production needs. V. Commissioning of the desulfurization system: 1) Once the pressure in the reaction system reaches normal levels, qualified amine solution is introduced into the unit. 2) The lean solvent pump is started in accordance with the procedures. 3) Establish a circulation for the amine solution. 4) Adjust the operation to control the H2S concentration in the recycle hydrogen at 500~1000 PPm. 5) Switch the acidic gas to the flare and return to the normal process. VI. Safety and environmental protection precautions during commissioning 1) Thorough dehydration of the oil in the distillation system is necessary to prevent pump cavitation ； 2) Oil transportation and dehydration must be monitored by a dedicated person; it is strictly prohibited to discharge the stored oil into the underground sewage system ； 3) During the startup process, it is necessary to monitor the liquid level carefully to prevent any leaks or spills ； 4) Operate strictly in accordance with the specified rates of temperature and pressure increase to avoid damaging the equipment. 5) Strengthen the connection between upstream and downstream units as well as with the dispatching department, to ensure smooth flow of oil in and out of the units. 6) During the startup process, it is necessary to properly isolate the high-pressure and low-pressure systems.

We only used nitrogen for pressure testing at 7.0 Mpa during the first start-up. From now on, nitrogen will be used for pressure testing up to 2.0 Mpa, followed by a thorough inspection; once airtightness is confirmed, the cycle hydrogen compressor system will be started to carry out the hydrogen replacement and temperature rise process, with checks at 3.0 along the way ； 4.0 ； 5.0 ； 6.0 Constant-pressure airtightness

Nitrogen can be used at the start of operation; pay attention to controlling the compression ratio of the compressor. Hydrogen should be used for raising the reaction temperature to prevent the nitrogen compressor from overheating. It can be used for a flame-out test, as hydrogen burns blue at night – be careful with heat buildup

The initial startup process is rather complicated; all areas where leaks might occur, such as flanges and instrument connections, need to be inspected. It’s generally good to complete one stage per day; in some cases, multiple attempts are required, and major leaks may arise, necessitating emergency pressure relief at any time. In the future, starting work will generally not be very troublesome; the main focus will be on checking areas where leaks might occur or that have been modified. 1. The reaction system must be airtight with nitrogen; generally, the airtightness is achieved at around 30 kilograms of pressure. Hydrogen is used later on, but in some cases nitrogen is used for airtight sealing from the beginning, mainly to make it easier to address any issues that may arise. 2. Drying of the reaction system: It is dried before loading the catalyst, and usually done together with furnace drying for the first time. 3. Airtightness of the raw material and distillation systems: Use nitrogen to ensure airtightness; careful inspection is necessary, as leaks before operation can cause problems.

Correction for floor 3: The nitrogen gas tightness can reach 7.0 MPa; we have achieved 10.0 MPa. Since no circulation hydrogen compressor is needed when using nitrogen for gas tightness, there is no need to worry about high outlet temperatures. Personal advice: When testing for nitrogen gas tightness, it is necessary to reach the highest pressure and conduct a thorough inspection. For hydrogen gas tightness testing, there are specific critical requirements: under hydrogen operation, the pressure must not exceed 1/3 of the design pressure as long as the reactor inlet temperature is below 135 degrees and the wall temperature is below 95 degrees. Therefore, when hydrogen is airtight, heating is required, and in such cases the ordinary soap water method cannot be used for airtightness testing. Only gas monitoring methods can be used, and this method is highly affected by the environment. Checking with the lights off also cannot detect small amounts of leakage. Therefore, using nitrogen with good airtightness can reduce the likelihood of hydrogen leakage.

Why isn’t there anything on accidents and prevention?

1. Device airtightness and catalyst drying: After the catalyst is loaded, the reaction system must be purged, made airtight, and the catalyst dried. Nitrogen circulation heating is typically used to dry and dehydrate the catalyst. 1.1 Preparatory work before catalyst drying (1) The manway cover of the reactor has been reinstalled and connected to the system, and the inspection has passed. (2) Notify the production scheduler, and contact units responsible for water supply and drainage, power generation, air separation, and oil supplies to ensure a proper supply of water, electricity, gas, and air ； Contact units such as laboratory testing, instrumentation, electrical engineering, and fitter work to coordinate with the commissioning of the equipment. (3) All moving equipment is in good standby condition; pressure gauges have been installed on all parts of the equipment, and the instruments have been calibrated and are ready for use. (4) The nitrogen source shall meet the gas requirements for the commissioning of the facility ； The nitrogen purity is required to be >99.5%, and the oxygen content

During the first startup, nitrogen sealing can achieve the design pressure; during the second startup, when the pressure exceeds the hydrogen embrittlement limit specified for the reactor, it is necessary to raise the temperature by starting the recycle hydrogen compressor. Since the outlet temperature rises under nitrogen conditions, hydrogen sealing is required.

Chapter 2: Comprehensive Inspection of Plant Process Equipment Section 1: Purpose of the Inspection Before the hydrogenation plant is put into operation for trial runs, a comprehensive inspection of the project quality must be carried out in accordance with the design requirements, to ensure the safe startup and operation of the plant. 1. Check whether the process flow, automatic control flow, and public systems after the project is completed meet the design requirements and production needs of the facility. 2. Check whether the project quality meets the design specifications, and whether there are any defects or potential risks. 3. Check for any process modification projects ； 4. Check whether the pumps, hydrogen compressors, and other equipment are ready for commissioning. Section 2: Inspection Contents 1. Overall device 1.1 Whether the equipment is installed in accordance with the design requirements, whether all components are available, whether the construction quality meets the design standards, and whether the process flow complies with the specified requirements. 1.2 The ground structure of the facility is vertically intact; sewer wells, drainage ditches, underground tanks, underground cables, and trench covers are all present in good condition. The office building, control room, power distribution room, compressor room, as well as the roads and floors are in good condition. The lighting and communication systems meet the design requirements. 1.3 Are there any issues with the process pipelines and individual equipment of each system? The construction of pipe bridges, pipe racks, pipe supports, pipe hangers, pipe clamps, insulation systems, heat tracing systems, ladders, guardrails, frames, platforms, etc., meets the required standards, and they are secure and undamaged. 1.4 Check whether fire-fighting equipment, fire protection facilities, personal protective equipment, and gas masks are available and in good working condition, and whether safety and fire escape routes are unobstructed. 2. Process pipelines 2.1 Check each process pipeline according to the process flow diagram, following its path, to verify whether the connections to and from the equipment meet the requirements. 2.2 Whether the material diameter of the process pipelines, as well as the materials of valves, flanges, gaskets, bolts, and nuts, meet the design requirements. 2.3 Alloy pipelines, fittings, and accessories in high-temperature and high-pressure systems shall be identified using spectroscopy. Ultrasonic thickness testing shall be conducted on both alloy pipelines and thick-walled carbon steel pipes used in such systems, to ensure the accuracy of the material composition and wall thickness; a dedicated person shall be assigned to carry out these inspections. 2.4 Check whether the valves, check valves, safety valves, control valves, steam traps, flow orifice plates, pressure gauges, blind flanges, and other components on the process pipeline are installed correctly; ensure that all valves have been pressurized, that the packing in the valves is properly installed, that the valves operate smoothly, and that all bolts are tightly secured. 2.5 The pipeline has passed the hydraulic test, the welds meet the design specifications, and the construction records are complete. 2.6 The process pipelines shall be anti-corrosion treated, painted, insulated, and heated as specified in the design. 2.7 Check the process pipeline for any incorrect wiring. 3. Pumps 3.1 Are the nameplates complete and accurate, and do the parameters match those of the equipment? 3.2 The foundation base of the pump is stable, intact, and smooth, with the anchor bolts fully tightened. Waste discharge is reasonable. 3.3 The oil cups, oil level gauges, check valves, pressure gauges, guards, and grounding wires meet the design requirements and are reliable and functional. 3.4 The pump is fully painted and has a shiny finish. 3.5 The inlet and outlet valves of the pump, as well as the pipelines for cooling water, seal oil, flushing oil, and lubricating oil, are all properly installed. 3.6 The trial operation seal should be properly installed, and the mechanical seal must be ready. 3.7 The inlet and outlet valves, check valves, and filters of the pump are installed correctly. 4. Compressor 4.1 Check the installation quality of the new hydrogen compressor and the circulation compressor in accordance with the installation drawings. 4.2 The pressure gauges, thermometers, control levers, control panels, load regulators, etc., have all been calibrated and are functioning properly. 4.3 The oil injector and lubricating oil station work well. 4.4 The nitrogen seal line, cooling water line, and grounding wire are properly installed. 4.5 The inlet and outlet valves, check valves, safety valves, and filters are properly installed and function smoothly. 4.6 The self-protection system for compressor oil pressure and temperature works well. 4.7 The foundation is solid and intact. The bolts are fully tightened. 5. Heating furnace 5.1 The material and structure of the furnace tubes meet the design requirements. 5.2 Check whether the induced draft fan is installed correctly. 5.3 Check whether the outer surface of the furnace tube is smooth and clean, and whether there are any severe rust, pitting, peeling, or similar defects. The furnace lining and chimney show no serious cracks or detachment, and the expansion joints meet the requirements. 5.4 The vacuum gauge, temperature measurement points, viewing ports, explosion-proof doors, fire suppression systems, burners, and air valves should be in good condition, and the pressure measurement pipes must be unobstructed. Are the smoke sampling ports and fire steam connections complete and in good working condition? 5.5 Check whether the flue baffle switch operates smoothly, whether the opening degree of the flue baffle matches the indicated position, and whether lubricant has been applied to the steel cables and all rotating parts. 5.6 Check whether the burner nozzles are aligned in the center, and look for any deviation, bent ducts, or clogged nozzles. 6. Tower 6.1 According to the general assembly diagram, check whether the orientation and number of openings in the tower are in accordance with the design. The internal components of the tower are complete with no detachment, and the material quality and installation standards meet the requirements. 6.2 Check the inlet and outlet pipelines connected to the tower to ensure that the valves (especially the flow direction of check valves) are installed correctly, and that pressure gauges, level gauges, safety valves, vent valves, etc. are present and in good working condition. Check whether the lead seal of the safety valve is intact and meets the process requirements. 6.3 Check whether the gaskets of the tray are properly installed, whether the bolt clamps are tight, whether the threads are damaged, and also verify that components such as the gas lift distribution tray and the liquid spray nozzles are in the correct positions. Check that the scaffolding used during installation inside the tower and other debris have been cleared away. 6.4 Check whether the foundation bolts use double nuts and whether there is full engagement; also inspect the tower structure and all its components for any signs of collision, damage, or severe rust. Check the static grounding condition. 6.5 Ensure that all manholes on the tower wall are properly tightened; check that there are sufficient gasket bolts and that the installation is correct. Is the tower’s insulation in good condition, and is the paint up to standard? 7. Cooling exchange equipment 7.1 Is the nameplate complete, and does the information on the nameplate match the equipment? 7.2 Check whether the installation is vertical and secure, and whether the foot bolts and static grounding are in good condition. 7.3 Check the shell surface for defects such as deformation, dents, cracks, rust, and pitting, and verify that there are no air leakage holes in the reinforcement plates of the pipes. The weld shall be free from cracks, slag inclusions, and pores, with undercut not exceeding 0.5 mm. 7.4 Check whether there are sufficient flange fastening bolts, whether their specifications are consistent, and whether there are any issues such as incomplete tightening, loose connections, cracks, or other damages. 7.5 Insulation and painting shall comply with the regulations. 7.6 Check whether the protective covers of each air cooler fan are in good condition, whether the motors, pulleys, and fans are properly installed and aligned, whether the belts are too loose or too tight; rotate the fan to verify that there is no collision or uneven tension during operation. 7.7 Manually operate the blinds to check whether the switches function smoothly, and whether the opening degree of the blinds matches the indications. Use the manual control system to increase or decrease the air pressure step by step, and observe the changes in the fan angle. 7.8 Check the pipe manifold for any deformation, bending damage, as well as cracks, pitting, defects, and rust. Check that the bellows plate is installed tightly and in accordance with requirements, and any debris inside the bellows should be removed. 7.9 Check whether the warped tube is compressed and deformed or bent. 7.10 Check whether the vent ports, sampling ports, inlet and outlet pressure gauges, and thermometers meet the production requirements. 8. Pressurized vessels 8.1 Is the nameplate complete, and does its content match the equipment? The container material and the installation of components meet the design requirements. 8.2 The container shall not be deformed; the foundation and supports must be secure, and the bolts must be tightened. Are the foundation bolts and static grounding up to standard? 8.3 Check whether the openings and connections of the container meet the process requirements, as well as the flow direction of the valves; in particular, ensure that check valves and globe valves are aligned with the process flow direction. 8.4 Whether the surface of the housing is smooth and straight, and whether there are any dents, deformations, or damages caused by poor manufacturing or collisions during installation. 8.5 Check the inspector wall and welds for cracks, slag inclusions, pitting, and severe rust; the root penetration shall not exceed 0.5 mm. 8.6 Check whether the flange sealing surface is smooth without scratches, whether the gaskets are installed correctly, whether the material specifications meet the requirements, whether the flanges are aligned properly, and whether there is any misalignment or deviation. 8.7 Check whether the bolt specifications and materials of the connection flanges (including manholes and connections) meet the requirements, whether the tightening force is consistent, and whether there is any under-tightening or loose fastening. 8.8 Check the installation of the internal components and ensure that any debris inside has been removed. 8.9 Whether the installation of level gauges, pressure gauges, temperature gauges, and vent valves meets the requirements. 8.10 Check whether the set pressure value of the safety valve meets the process requirements, and whether the lead seal is intact. 8.11 The raw material filter must be installed in accordance with the design requirements. 9. Reactor 9.1 Visual inspection of the reactor 9.1.1 Check for cracks or damage to the reactor foundation ； Are the anchor bolts tightened properly? Are double nuts being used? ； Check for any full buckling, as well as any tilting of the reactor. Check whether the nameplate is intact and accurate, and whether the static grounding meets the requirements. 9.1.2 Before installing the insulation layer, the shell wall (especially at the welds) and the openings for connecting pipes should be carefully inspected for any defects such as cracks, pitting, and damage. 9.1.3 Carefully inspect the bolts and nuts on each flange surface to ensure that their materials meet the requirements, and that their specifications (including bolt length) are consistent and in accordance with the standards; no bolts from different groups should be installed incorrectly or mixed together. Check the bolts and nuts for defects such as bending and cracks, and inspect the heads for any cracks or damage. After installation, the bolts should protrude by at least two to three threads; there should be no situation where they are fully seated or slip. 9.1.4 Before installation and reset, check whether the gaskets on each flange surface meet the material requirements; inspect their surfaces for any deposits, rust, scratches, etc., and assess the surface finish. Installation is not permitted if there are radial scratches or insufficient finish and other defects. 9.1.5 Check whether the specifications, length, grade, and orientation of the flanges at each opening connection meet the requirements specified in the drawings, as well as whether the reinforcement at the openings is adequate. 9.1.6 Check whether the fire protection layer of the reactor cluster foundation meets fire safety requirements. 9.1.7 Whether the ladders, platforms, and supports of the reactor meet the installation requirements, and whether normal operation and maintenance are convenient and reliable. 9.2 Internal inspection of the reactor 9.2.1 Carefully inspect the surface of the surfacing layer for cracks, pitting, rust, and damage; pay special attention to the corners where the support rings and connectors meet. 9.2.2 Check whether the material and specifications of various internal components meet the design requirements, whether there is any deformation, cracks, or damage in these components, and whether their installation locations are appropriate. 9.2.3 Check the installation of the distribution disk, cold hydrogen disk, and support ring. Check whether the installation positions of the clamps and shims meet the requirements, and whether the bolts are tightened evenly and properly. 9.2.4 Check whether the nuts on the distribution plate are tightened securely. 9.2.5 Check whether the installation of the outlet collector meets the requirements, whether the specifications of the stainless steel wire mesh comply with the design requirements, and whether there are any signs of damage. 9.2.6 Check whether the installation of the thermocouple meets the requirements, for any signs of bending damage, and whether the support is reliable. 9.2.7 Check whether the installation of the catalyst unloading pipe inside the reactor meets the requirements. 9.2.8 Check finally whether the inspector is clean. 10. Inspection of other equipment 10.1 All instruments in the entire system are properly installed and meet the design requirements; the model specifications and installation direction of the control valves also comply with the specified standards. 10.2 Are all DCS control circuits operating as per the design requirements, and are the detection points correct? All control valves operate flexibly and effectively. After being integrated into the DCS system, check the operation of all instruments; compare and verify the indication values of the key instruments, and there should be no abnormalities. All control circuits must be calibrated and found to be satisfactory. 10.3 Are the alarms for flammable and explosive gases installed as required by design and functioning properly? Have all the alarm systems and indicator lights been installed completely, with no missed connections or similar issues? 10.4 Check whether all primary instruments (level gauges, flow meters, thermocouples, differential pressure gauges) are installed in accordance with requirements and whether their indications are correct. 10.5 The heating furnace, feed pump, hydrogen compressor, and emergency venting safety interlocks are properly calibrated. 10.6 All electrical equipment enclosures shall be equipped with nameplates to indicate whether they meet the design and production requirements; explosion-proof electrical equipment shall have obvious explosion-proof markings, and all of them shall come with a factory certification of conformity; enclosed electrical equipment shall be properly sealed. Check whether all equipment such as control circuits, measuring elements, control valves, field instrument cabinets, field gauges, and gauge boxes are present, and whether the markings are correct and clear. 10.7 Check whether the operation of each control valve is smooth and flexible, whether there is any looseness or sticking, and whether it can be fully opened and fully closed. 10.8 Check all electrical equipment (motors, electrical switches) for any defects such as damaged or compromised cable grounding caused by construction work, as well as poor insulation. 11. Inspection of safety facilities 11.1 Check the pipes of the fire protection water system against the drawings to ensure that the installation of fire-fighting equipment meets the requirements, that flanges and joints are properly sealed, and that valves and nozzles function smoothly. 11.2 Check whether the fire-fighting equipment at each fire station is complete. 11.3 Check whether the piping of the fire steam system meets the requirements, and whether the number of steam connections is sufficient to meet fire protection needs and facilitates operation. 11.4 Check whether the fire alarm system and communication facilities have been installed and are functioning properly. Are the fire roads unobstructed? 11.5 Is the safety valve set at the specified pressure and fully sealed with lead seals?

The responses from floors 2, 3, and 11 were very good and comprehensive; those who need this supplementary information can refer to them. Thank you