Looking for operation training materials for the Shanghai Dalong 4M12Q carbon dioxide compressor

Chapter 1: Position Overview I. Job Responsibilities The responsibility of this position is to compress the carbon dioxide gas supplied from the low-temperature methanol washing process to around 8.0 MPa, so that it can be used in chemical processing operations. Alternatively, the nitrogen delivered from the blanking process is compressed to 8.0 MPa for use in the gas supply process. II. Process Flow 1. Brief description of the process gas flow 1) Lubricating oil system The lubricating oil serves to lubricate, reduce friction, and cool the mechanical components ； For cylinders and gaskets, the oil film formed by the lubricating oil can prevent gas leakage, serving as a form of sealing. That is, lubricating oil serves functions such as lubrication, cooling, and sealing. The 4M compressor has two lubrication oil circuits ； ○1-cylinder packing lubrication system, lubricated by a plunger-type oil injector driven by an independent motor. Distribution of lubrication points ； Cylinder: Stage 1 cylinder – 4 points; stages 2, 3, and 4 cylinders – 2 points each (during normal production, stages 1 and 2 cylinders are lubricated with less oil) ； Three-stage, four-stage cylinders with oil-free lubrication). Fillers: 1 each for fillers of grades 1, 2, 3, and 4 (a total of 14 lubrication points). Our unit is currently using 150# cylinder oil. The kinematic viscosity at 100°C is 24.5 (mm2/s), and the flash point is 270°C. ○A 2-circulation lubrication system, with a gear oil pump driven by an independent motor, is used to lubricate the moving parts of the compressor. The process is as follows ； Tank → Oil pump → Oil cooler → Oil filter → Main bearing shells → Crankshaft journals → Big-end bearings of connecting rods → Small-end bearings of connecting rods → Bypass control valve → Crosshead pin → Upper and lower crosshead slides → Return oil flows through the intermediate housing → Crankcase → Return oil pipe → Return oil filter in the tank → For reuse in the tank. The oil returning from the motor bearings flows through the return pipeline and mixes with the oil returning from the crankcase, before being circulated back to the oil tank for reuse. 2) Gas flow: 1. When the low-temperature methanol washing unit is operating normally (and nitrogen supplied by the air separation unit is used when the unit is not operating properly), the low-pressure carbon dioxide gas coming from the low-temperature methanol washing unit is compressed to increase its pressure. After passing through the primary inlet buffer, the carbon dioxide gas enters the compression cylinder where it is compressed to approximately 0.25 MPa before being discharged. Through a discharge buffer, a water cooler, and a separator. After entering the second-stage inlet buffer, it proceeds to the second-stage cylinder where it is compressed to approximately 0.98 MPa, then goes to the second-stage outlet buffer, the second-stage water cooler, and the second-stage separator. It enters the three-stage inlet buffer, is compressed by the three-stage cylinders to about 2.8 MPa, then proceeds to the three-stage outlet buffer, the three-stage water cooler, and the three-stage separator, before entering the four-stage inlet buffer and being compressed by the four-stage cylinders to about 8.0 MPa. It enters the four-stage outlet buffer, the four-stage water cooler, and the four-stage separator; the gas after separation is sent to the gasification process for use. 2. This position features a loop between the outlet pipeline of Stage 1 separator and the pipeline before the inlet buffer of Stage 1, with a check valve installed on this pipeline. A loop is provided between the outlet pipeline of the fourth-stage separator and the pipeline ahead of the first-stage inlet buffer, and a four-way one-valve is installed on the pipeline. Bypasses are installed from the inlet pipeline of the fourth-stage water cooler to the outlet pipeline of the same cooler to meet the gas temperature requirements of the gasification unit. 3. This position is equipped with safety valves on each separator to ensure the safe operation of the compressor. Vent valves are installed on the four outlet pipelines. 4. Air leakage from the packing at each stage of the compressor, as well as the gas released by the vent valve and after the safety valve activates, is directed to a safe location for venting. 5. Process flow diagram: 3. Cooling water system – Cooling water serves to lower the temperature of gases, cool equipment, and reduce friction. The circulating cooling water coming from the boundary area enters the water jackets, cylinder heads, various stuffing boxes, and coolers of the first, second, third, and fourth cylinders, as well as the cylinder base of the first stage, through the inlet valves in the corresponding pipeline systems. After exchanging heat with the heat medium, it returns to the main return pipe for circulating cooling water and goes back to the boundary area. The flow diagram of the circulating water system is as follows: 4. Main process control parameters (I) Pressure, in Mpa (gauge pressure) – Design parameters for the pressure section: Inlet of stage 1: ≥0.02 MPa; Outlet of stage 1: ≤0.25 MPa; Outlet of stage 2: ≤0.98 MPa; Outlet of stage 3: ≤2.8 MPa; Outlet of stage 4: ≤8.0 MPa. Oil pressure at the control panel: >0.25–0.4 MPa. Pressure difference across the oil filter: ≤0.1 MPa. Cooling water pressure: 0.25–0.35 MPa. (II) Temperature (under design conditions): Inlet temperature of each stage: ≤40 °C; Outlet temperature of each stage: ≤150 °C; Oil temperature after the oil cooler: ≤35 °C; Temperature of the main shaft bearings: <65 °C; Temperature of the motor bearings: <70 °C; Temperature of the packing in each stage: ≤75 °C; Temperature of the motor stator: ≤90 °C. (III) Voltage, current, power: 1. Voltage: 10,000 V; 2. Current: 81 A; 3. Motor power: 1,200 KW; 4. Power factor: 0.9 leading. (IV) Interlock devices: Alarms and automatic shutdown mechanisms: 1. If the inlet gas pressure is ≤0.012 MPa or ≤0.008 MPa, an alarm is triggered and the auxiliary oil pump starts automatically. If the pressure is ≤0.20 MPa or ≥0.30 MPa, operation is allowed. If it reaches ≥0.45 MPa, an alarm is issued and the auxiliary oil pump must be stopped manually. If the pressure is ≥0.1 MPa, an alarm indicates a high pressure difference across the oil filter. Lubricating oil is heated automatically when the temperature is ≤10 °C; heating stops when the temperature reaches ≥30 °C. 3. If the cooling water pressure is ≤0.2 MPa or ≤0.18 MPa, operation is allowed; if it is ≥0.25 MPa, operation is permitted. 4. If the temperature of the main shaft bearings is ≥65 °C or ≥70 °C, respectively… 5. If the temperature of the motor bearings is ≥70 °C or ≥75 °C, respectively… 6. When the main motor starts, it should not experience asynchronous operation or overcurrent within five seconds. 7. The main engine cannot be started if the cranker is not in the operating position. 8. The main engine cannot start if the oil pump does not operate. (Tentative) 9. Overcurrent in the circulating oil pump leads to pump shutdown and system shutdown. 10. Motor stator temperature ≥ 120°C ≥ 130°C. (V) Setting pressures for safety valves: Outlet 1 – 0.3 Mpa; Outlet 2 – 1.1 Mpa; Outlet 3 – 3.2 Mpa; Outlet 4 – 8.5 Mpa. VII. Performance of the main equipment in this position: 4M16—105/80 carbon dioxide compressor. Structure type of the compressor: 4M symmetric balanced type, four rows, four stages, water-cooled, oil-free or low-oil lubrication, reciprocating piston type. (All pressures are absolute pressures) 1. Volumetric flow rate (at stage 1 suction condition): 105 m³/min 2. At stage 1 suction condition: Pressure = 0.12 MPa, Temperature = 40°C, Final exhaust pressure = 81 MPa 3. Gas composition: (mol%) CH3OH 0.0271, CO2 99.1969, H2 0.1619, N2 0.0647, CH4 0.0020, CO 0.5475 4. Piston stroke: 320 mm 5. Rotational speed of the main shaft: 333 r/min 6. Average piston speed: 3.552 m/s 7. Diameter of cylinders at each stage: Stage 1 (double-acting): ∮900 mm; Stage 2 (double-acting): ∮520 mm; Stage 3 (double-acting): ∮300 mm; Stage 4 (double-acting): ∮180 mm 8. Diameter of the piston rod: 80 mm 10. Shaft power of the compressor: 1200 KW 11. Consumption of cooling water for coolers and cylinders: ≤110 t/h; Supply pressure: 0.3 MPa (gauge pressure); Inlet water temperature: ≤40°C 12. Oil consumption for cylinders: Appropriate amount Chapter 2 Basic Theory 1. Model of the compressor: 4 M 16 —— 105/80; Final exhaust pressure = 80 kg/cm²; Displacement = 105 m³/min; Piston thrust = 16 tons; Cylinder arrangement: M-type; Number of cylinder rows = 4 2. Working principle of reciprocating piston compressors: Reciprocating compressors consist of cylinders and pistons, and they compress gas by means of the reciprocating motion of the pistons within the cylinders, bringing the gas molecules closer to each other thereby increasing the gas pressure. Due to the continuous back-and-forth movement of the piston within the cylinder, the cylinder cycles through the intake and exhaust of gases. One complete back and forth movement of the piston is referred to as one working cycle, and the distance covered by the piston with each movement is called the piston stroke. The working process of compressed gas can be divided into the following four stages: 1. Expansion process: As the piston moves to the right (from point A to point B), the volume of the cylinder increases, the pressure drops, and the remaining gas inside the cylinder continues to expand. 2. Inflation process: As the piston moves to the right, the volume of the gas in the cylinder on the left side of the piston increases, causing the pressure to drop. When the pressure of the gas inside the cylinder is slightly lower than that in the gas inlet pipe, the gas in the inlet pipe pushes open the intake valve and enters the cylinder. At this point, the gas pressure inside the outlet pipe is higher than that inside the cylinder; thus, the closure of the outlet valve results in an inhalation process. 3. Compression process: When the piston reverses direction and moves to the left. The gas is compressed by the piston, its volume gradually decreases and the pressure rises. The intake valve closes, while the exhaust valve cannot open due to the pressure in the outlet pipe. The mass of gas inside the cylinder remains constant as the pressure continues to increase; this process is known as the compression process. 4. Discharge process: When the gas pressure inside the cylinder is higher than that of the gas in the outlet pipe, the gas inside the cylinder pushes open the outlet valve and enters the outlet pipe, until the piston moves to the left end point, thus completing the discharge process. Three processes of compressing gases: A large amount of heat is generated during the compression of gases, and this is due to work being done on the gas by an external force. The greater the pressure on a gas, the higher its temperature rises. The power consumption during the compression process is related to the heat generated during gas compression. Depending on the degree of heat removal, the process of compressing a gas can be divided into the following three types: 1. Isothermal compression process. During the compression of gas, an external cooling source is used to remove promptly the heat energy generated by the compression process, thereby increasing the pressure of the gas in the cylinder while keeping its temperature constant. This process is an isothermal compression process. Due to the limited cooling efficiency, it is impossible to maintain a constant temperature inside the cylinder; therefore, this process is an ideal compression process. (Least work is required for isothermal compression) 2. Adiabatic compression process. During the compression process, the cylinder is completely isolated from the surrounding environment, maintaining an adiabatic state with no heat exchange with the outside world; all the heat is used to raise the temperature of the gas inside the cylinder. Since perfect insulation of the cylinder is impossible, heat is always lost to the surrounding environment; therefore, this process is also an ideal compression process (ideal adiabatic compression requires the most work). 3. Variable compression process. During the actual compression process, it is impossible to avoid heat loss to the surroundings, nor is it possible to remove all the heat in order to maintain a constant temperature; thus, it falls between isothermal compression and adiabatic compression, and is referred to as polytropic compression. The area ABCD enclosed by the isothermal compression curve is smaller than the area ABCD enclosed by the adiabatic compression curve. The size of this area also indicates the amount of work required. Therefore, in order to reduce the amount of work spent during compression, it is necessary to make the polytropic process more similar to an isothermal process. The more heat generated by compression that can be removed, the better; thus, a better cooling effect results in less energy consumption and is more economical. 3. Clearance volume: The clearance volume refers to the total space between the piston and the cylinder at the end of exhaust, when the piston is at its dead center position, as well as the space in the passages connecting the valves to the cylinder. The reason for leaving a clearance volume is that having such a clearance in the cylinder brings many benefits to the installation and safe operation of the compressor. These benefits are mainly reflected in A. preventing damage caused by collisions resulting from loosening or thermal expansion during the installation, adjustment, and operation of the machine shaft, piston rod, cylinder head, or other components. B. The gas remaining in the clearance volume acts as a buffer when new gas is drawn in, enabling a smoother operation of the intake valve and reducing the impact and damage to the valve and its components. C. When mist is carried in with the incoming gas, or even when a small amount of liquid is present, the piston forces this liquid into the clearance volume, where it is gradually expelled from the cylinder along with the gas, thereby reducing the risk of damage to the compressor. D. The load can be adjusted through the clearance. Control of clearance volume: Leaving a clearance in the cylinder brings many advantages to the assembly, operation, and safe use of the compressor. However, if too much clearance is left, it not only brings no benefits but also reduces the compressor’s production capacity. Therefore, under normal conditions, the clearance volume in a compressor cylinder is approximately 3% to 8% of the cylinder’s working volume; whereas in compressors with higher pressures and smaller diameters, the clearance volume is usually 5% to 12% of the cylinder’s working volume. Chapter 3 Normal Production Operations I. Initial Commissioning Initial commissioning refers to the startup of a compressor that has been newly installed or overhauled. The procedure includes purging the equipment and pipelines, conducting a no-load test run, performing a load test run, and then transitioning to normal production. During the equipment pipeline purging, no-load commissioning, and load testing phases, there is a commissioning plan prepared by the installation unit. The process operators shall cooperate with the commissioning; the following plans for purging equipment pipelines, conducting no-load tests, and load tests are provided for reference only. (1) System purging 1. Purpose of purging: By purging the equipment and pipelines in the system, rust, dust, slag, sediment, debris, and oil residues within the pipes and equipment are removed, thereby preventing blockages and damage to equipment, valves, fittings, and instruments, and thus creating conditions for the subsequent testing phase. 2. Principle of purging: upstream first, then downstream ； Main pipe first, then branch pipes ； Low pressure first, then high pressure ； Proceed in stages, step by step, while ensuring comprehensiveness ； 3. Requirements for purging: Adequate air supply and flow rate should be available, ensuring that overpressure is not incurred ； Blowing into downstream equipment such as coolers is not permitted until the upstream pipeline has been properly purged ； Protective measures should be taken for thermometers, pressure gauges, control valves, safety valves, etc. before purging; remove them if necessary ； 4. Regulations during the purging process: It is necessary to follow unified instructions, implement appropriate safety measures, isolate an area around the purging outlet, and ensure that the purging outlet is not directed at people or equipment ； 5. Inspection method for dust removal: Use a wooden board painted white to blow against the dust removal outlet for five minutes; it is considered satisfactory if no visible dust or dirt remains on the paint ； (II) No-load test run 1. Purpose of the test run ○1 To ensure proper rotational running-in of all components of the transmission mechanism (crankshaft, connecting rods, etc.). ○2 Ensure that the filler and piston rod, as well as the piston rings and cylinder walls, are in good working condition. ○3 Check the tightness of operation of the lubrication system and the cooling water system. ○4. Promptly identify and address any issues in monitoring components such as the main unit, motors, and measurement and control instruments, thereby laying the foundation for pressure testing and normal production. 2. Commissioning steps ○1 Preparation work: A. The installation personnel check whether all components of the main unit have been installed properly, and ensure that the operating clearances of all moving parts meet the required standards. B. Notify the electrician to check whether the motor’s insulation and the electrical switches meet the required standards, and notify the instrumentation personnel to verify whether the measuring instruments and interlock control protection devices are in good working condition. C. Clean the area to keep the surfaces of the equipment and test benches clean and tidy. D. Clean and inspect the circulating oil system (including the oil tank, crankcase, oil pump, filter, oil cooler, oil pipes, valves, etc.). In particular, the iron shavings and hard debris in the oil circuit system must be thoroughly removed. After thorough cleaning, add fresh lubricating oil to the tank, start the oil pump, and check its operation as well as for any leaks in the oil circuit. (The oil pressure must not be lower than 0.3 MPa.) E. Clean and inspect the oil injector to ensure normal operation, unobstructed oil flow, and no leakage points; the oil injection rate should be 8–10 drops per minute (this rate can be increased slightly during testing). After normal production, the amount of oil added can be reduced; during the commissioning phase, a small amount of oil can be added in stages 3 and 4 to ensure that the oil quality remains clean. F. Open the main return valve for cooling water, as well as the inlet and outlet valves for cooling water in the cylinder water jackets, packing, cylinder head, cylinder block, and oil coolers, water coolers, etc.; check whether the water pressure, quality, and volume meet the required standards. G. Check whether the interlocks for water pressure, oil pressure, and main bearing temperature are sensitive and reliable. H. Remove the inlet and outlet valve covers and valves of each section of the main unit, as well as all gas pipelines connected to the main unit. Install 10–20 mesh wire mesh at the air intake port of the host. ○2 Test run steps: A. Open the cooling water supply valve and adjust the water flow. B. Start the circulating oil pump, adjust the oil pressure to above 0.3 MPa, inject sufficient lubricating oil into all driving friction surfaces, and then stop the pump. C. Start the oil injection pump to pre-fill the cylinder with an adequate amount of lubricating oil, then stop the pump. D. Rotate the crankshaft several times to form a layer of lubricating oil film on all the friction surfaces and the cylinder wall surfaces. (When using the turntable to rotate the shaft, first move the turntable handle to the rotation position before starting the motor for rotation; run it for 3–5 minutes. There should be no dead points when rotating the shaft in either direction, indicating that the turntable is sensitive and reliable. Then stop the motor and move the turntable handle back to the start position.) ) E. Contact the dispatching to supply power to the main unit from the substation. F. Start the circulating oil pump and the oil injection pump. G. First no-load run: Start briefly and then stop immediately. Determine whether the rotation direction of the compressor’s main shaft is correct (viewed from the machine body side, the motor rotates in a “counterclockwise direction”). Then restart the host; once it reaches full speed, stop it and check for any knocking sounds or vibrations during short periods of operation. If such issues are present, address them promptly after stopping the machine. H. Second no-load run: Start the main engine and run it for 5 minutes, carefully listening, observing, and feeling for any abnormal phenomena, and check whether the oil ring of the outer bearing of the motor rotates together with the motor shaft. Immediately after shutdown, check the temperature of all working surfaces; the temperature should not exceed 45°. If a high temperature is detected, the cause should be identified and eliminated. Verify the temperature display of the main bearings and motor bearings. I. Third no-load run: Start the main unit for 2 hours. Use interlock shutdown to test whether the interlock is sensitive. After the main machine has completely stopped running, shut down the circulation oil pump and the oil injector. After parking, carefully inspect all moving parts as well as any noises or vibrations at the connection points; if any abnormalities are detected, the cause should be identified and addressed promptly. (Each time a shutdown inspection is carried out, it is necessary to contact the dispatcher to inform the substation to turn off the main machine power; the machine must not be inspected while it is still powered on.) ○3 Items to check during no-load test run: A. Whether the bolts at all connection points are loose and the vibration levels of the main machine and auxiliary machines. B. Check whether the operating sounds at various parts are abnormal. C. Check whether the lubrication and oil supply of the transmission components and cylinders are abnormal, examine the degree of heating on the friction surfaces, and look for any signs of scuffing. D. Observe the circulating oil tank, oil level, oil quality, oil temperature, and oil supply status, as well as whether the filter is clogged. E. Check the operation of electrical equipment and instruments. F. Inspection of the items scheduled by the installer. ○4 Precautions for testing: A. Continuous starting of the main unit is not allowed; there must be a gap of at least 10 minutes between each start. B. Before each trial run, the machine must be turned over first. C. Cleaning the area and performing other tasks unrelated to testing are not allowed during the testing period, to prevent metal shavings and dust from entering the cylinders. D. Oil should not be poured in too early before startup, and the oil pump should be stopped as soon as possible after shutdown to prevent liquid from accumulating in the cylinders. ⑤During no-load operation, a test run record should be made every 30 minutes, and the following requirements must be met: A. No abnormal noises during operation ； B. The lubricating oil is functioning properly ； C. The bearing temperature rise shall not exceed 30℃ ； D. The temperature at the stuffing box gland shall not exceed 85℃ ； E. The piston rod temperature shall not exceed 85℃ ； F. Motor temperature rise, current not exceeding the values specified on the nameplate ； G. The electrical metering equipment is operating normally ； H. The temperature of the outer wall of the medium-body slide shall not exceed 60°C (as close as possible to the slide). (III) Pressure testing 1. Purpose of testing: To examine and understand the operating conditions and various performance characteristics of the compressor under normal operating pressure, as well as its working parameters, motor load, and the reliability of the measurement and control devices. It also aims to assess the airtightness of the equipment and pipelines, as well as the vibration levels of these components. This helps to identify and eliminate any abnormalities that may occur in the compressor under normal operating conditions, so that the compressor can function properly under production conditions and achieve satisfactory results. 2. Testing medium ； Using air or nitrogen for testing allows for advantages such as saving production time and enabling the detection and correction of faults. However, when air is used as the testing medium, working parameters such as the gas outlet temperature at various stages and the motor load change, and the lack of an intermediate pumping process in the flow leads to a redistribution of pressures. The nitrogen commissioning plan needs to be appropriately adjusted. 3. Commissioning steps ○1 Check whether all systems of the compressor are in the pressurization testing mode. Only after it has been confirmed that the assembly of all components is proper, that all stationary equipment, pipes, fittings, valves, etc. have been properly connected following purging, that the valves function correctly, that the lubrication system and cooling water system are operating properly, that the measuring instruments and control protection devices are sensitive and reliable, and that the motors and electrical equipment are safe and reliable, can pressure testing be carried out. ○2. Remove the inlet flange of the primary inlet buffer to use it as the air source inlet, and install a filter screen. ③Check the valves that should be opened and those that should be closed: a. Valves that should be opened: Primary loop 1, Primary loop 4, vent valve, and the drain valves of each stage separator (close them after draining completely); also open the pressure gauge valve. Valves that should be closed: the inlet main valve, the outlet main valve, and the bypass valves of the four-stage water cooler. ○4-way cooling water supply and return main valves: used to adjust the amount of water in the compressor’s cooling system, as well as to check the water distribution. ⑤Start the circulating oil pump to adjust the oil pressure; the oil injection pump starts working properly, and the turbine is rotated a few times. ○6 After checking that there are no abnormalities, stop the barring; move the barring handle to the start position. ○7. Notify the scheduler; have the electrical and instrumentation personnel arrive at the site, and start the main unit after confirmation. ○8 Check the operating conditions of the transmission components and moving parts, the motor and current, the circulating oil pressure, and the temperature of the main bearings. ○9. Run under no-load conditions for 10–15 minutes; if no problems are detected, proceed with load testing. The pressure for the load-testing operation is determined based on the output pressure; increments of 1.0–1.5 MPa are used, with the final air-driven output pressure reaching 6.5 MPa. The pressure testing can be carried out in stages, with the pressure increase and stabilization time for each stage being no less than 20 minutes. The specific procedures for increasing and controlling the pressure are as follows: A. Slightly open the relief valve (while adjusting the final pressure), and use one valve per circuit or one valve per four circuits to regulate the final pressure. B. Use motor excitation to control motor current. C. Once the pressure at the four outlets reaches 6.5 MPa, it enters the full-load testing phase; the testing duration must be no less than 16 hours. The pressure control value for the four outlets is 6.5 MPa (to be adjusted using the four-way valve or the vent valve, with the one-way valve used in conjunction for adjustment; the pressures in the remaining sections shall not exceed the values specified by the process requirements). D. Once the full-load test is completed, the airtightness test of the four-output main pipes can be carried out, using the process specification pressure. 4. Commissioning inspection items ○1 Circulating oil pressure and temperature, cooling water pressure and temperature, measuring instruments, and control protection devices. ○2. Check the noises of various components of the compressor, as well as the temperature of the friction surfaces; inspect these friction surfaces after pressure testing. ○3. Vibration conditions of the equipment pipelines, and whether there are any leaks in the various systems of the compressor. ○4 Operation status of motors, electrical systems, and instruments. 5. Precautions during testing ○1 Pressurization and the handling of abnormal conditions must be carried out under unified command; emergency situations require immediate action. ○2 Careful inspection and preparation are required. ○3 For the air test run, the maximum pressure at the four outlets is set at 6.5 MPa; however, in the event of any abnormal operational conditions, the valves in each circuit or the relief valves can be opened to reduce the load on each section, thereby ensuring that the equipment does not operate under overload conditions. 6 System purging: Open the large nitrogen inlet valve, use a turntable to purge the compressor with nitrogen, and vent the unqualified gas through the relief valve. A O2 content of ≤0.5% is considered acceptable; replacement should be carried out section by section. It must be replaced in every gas system pipeline, leaving no dead corners. II. Normal Production Operations (I) Normal Startup: (1) Preparatory work before startup – valves that need to be opened include the main carbon dioxide inlet valve, the return valves for stages 1 and 4, the vent valve, the valves at the base of each pressure gauge, the oil injection valves at each oiling point, and the valves for the level gauges in each separator. (2) Valves to be closed: the main nitrogen inlet valve, the main outlet valve, and the bypass valve of the four-stage water cooler. (3) Conduct a thorough inspection downstairs; after opening the carbon dioxide inlet valve, use backwashing to check whether there is water in each stage of the separator. If water is present, it must be drained. Then close the backwashing system, and at the same time check the oil level in the tank as well as the oil pump, turning the pump several times as a precaution. (4) Inspect the cooling water system; open the return valves on each section of the water coolers, as well as the return valves on the cylinder heads, cylinder liners, and cylinder blocks. Open the main return valve, adjust the water pressure to normal levels, and remove any air bubbles. (5) The main engine’s cranking function is normal, and the control lever is in the start position. (6) Start the circulating oil pump to adjust the oil pressure, and check whether the oil circuit is unobstructed. (7) Start the oil injection pump and check the oil injection condition. (8) Contact the dispatching department to supply power; confirm that all aspects related to process, instrumentation, electrical systems, and equipment are satisfactory, and sign the commissioning confirmation form. (9) Before starting the machine, the team leader contacts the dispatcher to confirm that it is safe to do so; the electrical technician checks that everything is in order and starts the main unit, then increases the pressure and supplies air according to the dispatcher’s instructions. (10) Close it once for one cycle, and close it slowly four times for one cycle to gradually increase the gas volume and the pressure at each stage, with the vent valve adjusted accordingly. (11) Use a four-way valve to regulate the pressure in the four sections; when the pressure at the four outlets is slightly lower than the pressure in the main outlet pipe, open the large outlet valve to supply gas to the vaporization unit and close the vent valve. (12) Gradually adjust the pressure and gas flow rate according to the scheduling instructions. (II) Normal parking: 1. After receiving the dispatch instructions, carry out the preparatory work before parking and contact the gas-using entity ； 2. Gradually close the four outlet valves; use a four-way control to regulate the pressure at each stage, with one valve per stage and the vent valve used in conjunction for adjustment. 3. After depressurization, run the machine idly for 3–5 minutes, then cut off the power to the main unit. Once the machine has come to a complete stop, start the shaft rotation device; stop it once the temperature has dropped ； 4. Stop the circulating oil pump and the oil injection pump ； 5. Stop the circulating water; in winter, leave the valve slightly open to allow flow and prevent freezing ； 9. Close the main carbon dioxide valve. (III) Reverse driving: 1. Follow the normal driving procedures to prepare the standby unit for operation, and make preparations to shut down the compressor. 3. After the compressor to be started has been inspected and found to be in good condition, the team leader contacts the dispatch team; once it has been checked by the instrumentation and electrical staff and confirmed to be fine, the electrical staff start the main unit, gradually increasing the pressure on the low-pressure side, with four-stage outlet pressures controlled using a four-way one-control system. 4. When the pressure at the four outlets is slightly lower than the pressure in the main four-outlet pipeline, open the four-outlet valve to supply gas to the vaporization unit. To shut down the system, close the four-outlet valve while supplying gas, and use the four-way control mechanism to regulate the pressure at each stage; utilize the vent valve to adjust the gas flow rate ； Pay special attention to maintaining a stable system gas volume. 5. After the machine that is to be shut down has been processed, the main machine is shut down depending on the operating conditions of the machine that is to be started (with exceptions for special situations). Then follow the parking procedures. 6. Further adjust the flow rate, temperature, and pressure of the gas to be supplied to meet the process requirements. Precautions: 1. Pressurization and depressurization must be carried out slowly to minimize fluctuations in system pressure ； 2. Close coordination is necessary between those who want to shut down the machine and those who want to start it up. (II) Emergency shutdown: 1. Cut off the power supply immediately ； 2. Quickly close the bypass valves at each section to prevent high pressure from leaking into the low pressure system ； 3. Send the appropriate signals to inform the dispatching department and relevant units and personnel ； 4. Quickly disconnect the compressor from the system by closing the four outlet valves and the one inlet valve ； 5. Open the pressure relief valve and slowly release pressure following the principle of releasing high pressure first and then low pressure. (Note: The pressure release speed should not be too fast.) 6. When releasing pressure, be careful to avoid accidents, overpressure, and interlock failures ； 7. Quickly determine the cause of the incident and take appropriate action ； 8. In special cases, the site should be protected (to keep the equipment in a safe state), and preparations for starting up should be made if necessary. Principles for emergency shutdown: Shutdown should be carried out in cases of accidents in the upstream or downstream sections, when there is a large amount of liquid or water present, in situations of explosion, fire, or other emergencies. This also includes situations such as damage to the main components of the press, severe vibration, bearing failure, fractures in the crankshaft, connecting rods, crossheads, and piston rods, as well as ruptures in cylinder pipes. Emergency shutdown is also applicable when there is significant air leakage from high- and low-pressure flanges, when the oil pressure suddenly drops to zero, when the oil injection pump stops working, when the motor is damaged, in case of electrical faults, power outages, water shortages, gas shortages, or any other situation that makes continued operation impossible and poses a serious threat to human safety and equipment integrity. Chapter 4: Precautions for Production Operations in This Position 1. Compressor Maintenance The changes in the operating conditions of the compressor are indicated by instruments, but the readings provided by these instruments are generally general in nature and have certain limitations; they often only indicate that a problem exists. It is not possible to determine the nature of the problem or its location; comprehensive information, analysis, and judgment from various aspects are required in order to draw conclusions about the various situations that occur. Operators rely on hearing, seeing, and touching to assist them ； By using the method of observation, it is possible to check whether the various rotating parts are loose or detached, whether the friction surfaces are properly lubricated, and to examine the readings on the various instruments. This allows one to understand the overall operating condition of the compressor, identify problems promptly, and determine the key issues, such as whether the gas, cooling water, and lubricating oil systems are functioning properly. Are the inlet and outlet temperatures of each section, as well as the temperatures of the bearing shells in each section, within normal ranges? Are there any signs of leakage or other abnormal phenomena? ； By using the method of listening, it is possible to determine with relative accuracy the operating condition of various components of the compressor. It is possible to detect whether there are leaks or damages in the inlet and outlet valves at different stages, whether the piston is leaking due to damaged piston rings, whether the airflow is pulsating severely, and whether there is excessive vibration in the pipes. When the compressor is operating properly, its sound is even and rhythmic; if the rhythm is lost and uneven noises and hums appear, it indicates that there is something wrong with the internal components or the cylinders ； By using the touch method, it is possible to determine the degree of heating, as well as to assess the friction and lubrication conditions, as well as the level of vibration. For oil drain valves, safety valves, and bypass valves in various sections, a gentle internal leak can generally be detected by touching them; only when the internal leak is severe can it be detected by listening, as such leaks cannot be seen on the pressure gauge ； The so-called “listening, observing, and touching” are not separate actions but are closely interconnected. In practical applications, by continuously gaining experience and applying these three methods, it is possible to accurately determine the causes of various abnormal phenomena and address them promptly ； 2. Control the pressure and temperature at each stage to ensure normal compression operation. ○1 Regularly check the changes in the temperature and pressure of the gases entering and leaving each stage, and strengthen coordination with the dispatch team, the low-temperature methanol washing unit, and the air separation unit. To ensure coordination and communication among processes such as gasification, if abnormal pressures and temperatures of the gas at the compressor’s inlet and outlet are detected due to issues in other processes, it is necessary to promptly inform the dispatch team and the relevant processes so that they can take appropriate action. ○2. Regularly check the performance of various water coolers, cylinder jackets, valves, pistons, etc., analyze and identify any abnormalities in the respective areas promptly, ensure that pressures and temperatures remain within normal ranges, and maintain proper operation of the compressor. 3. Perform operations such as starting, stopping, and reversing in accordance with the procedures, and adjust the gas flow rate promptly. ○1 Based on the actual needs of production and the requirements of the production supervisors, carry out operations like starting, stopping, and reversing as per the established procedures, and adjust the gas supply volume accordingly to ensure a coordinated and balanced production process. ○After the 2 compressors are started and operating normally, when supplying air to the subsequent processes, the outlet valve must be opened only once the outlet pressure is slightly lower than the main pipe pressure. During the shutdown of the compressor, when the outlet valve has not yet been fully closed, attention should be paid to the opening degree of the circuit valve to prevent gas and liquid from flowing back into the compressor or to avoid the outlet pressure exceeding the specified limits. ○3. The adjustment of gas volume should be done gradually to ensure stable production in all related processes. Generally, a one-time shortcut valve is used to adjust the air volume. When production is stable, efforts should be made to keep the circuit valve closed so that the compressor operates at full load, thereby reducing power consumption. 4. Prevent the compressor from developing negative pressure as well as the presence of water and liquids in the gas ○1 Strengthen coordination with the low-temperature methanol washing process, and pay attention to changes in the pressure of the gas entering the first stage of the compressor to prevent negative pressure from occurring. ○2. Improve the drainage of water accumulated in the separator to prevent liquid-laden gas from entering the cylinder. 5. External communications for this position: 1. The staff assigned to this position are under the direct supervision of the shift supervisor while at work. 2. Upon receiving production and technical instructions from superiors during working hours, one should immediately report to the team leader and carry out those instructions as advised; in special circumstances, execution should take place first before reporting to the team leader. 3. This position has business connections with the dispatching, low-temperature methanol washing, air separation, and gasification units; with the authorization of the shift leader, it is even more necessary to strengthen communication with these units. Chapter 5: Main Equipment of Compressors 1. Tube-and-plate Heat Exchanger with Flow Dividers. In this type of heat exchanger, water enters from the lower side and exits from the upper side; it flows through the tubes inside the internal components, where heat exchange takes place both in co-current and counter-current directions. Gas enters the tube side from the upper part of the heat exchanger’s shell, passes through the gas channels, and then, under the influence of the flow dividers, moves between the cooling tubes, allowing for heat exchange in both co-current and counter-current modes. Equipment Name, Container Category, Volume, Design Pressure, Operating Pressure, Pressure Test Pressure, Operating Temperature, Medium, Baffle Spacing, Net Weight of the Container: Primary Cooler – Category 1; Volume: 1.3 m3; Shell side pressure: 0.6 MPa; Tube side pressure: 0.6 MPa; Pressure test pressure: 0.4 MPa; Operating pressure: 0.25 MPa; Maximum allowable pressure: 0.75 MPa; Operating temperature: 40°C; Maximum temperature: 136°C; Medium: Cooling water; CO2; Baffle spacing: 100 mm; Net weight: 2847 Kg. Secondary Cooler – Category 1; Volume: 0.8 m3; Shell side pressure: 0.6 MPa; Tube side pressure: 1.2 MPa; Pressure test pressure: 0.4 MPa; Operating pressure: 0.95 MPa; Maximum allowable pressure: 0.75 MPa; Operating temperature: 40°C; Maximum temperature: 138°C; Medium: Cooling water; CO2; Baffle spacing: 95 mm; Net weight: 1960 Kg. Tertiary Cooler – Category 2; Volume: 0.7 m3; Shell side pressure: 0.6 MPa; Tube side pressure: 3.3 MPa; Pressure test pressure: 0.4 MPa; Operating pressure: 2.8 MPa; Maximum allowable pressure: 0.75 MPa; Operating temperature: 40°C; Maximum temperature: 130°C; Medium: Cooling water; CO2; Baffle spacing: 80 mm; Net weight: 1706 Kg. Quaternary Cooler – Category 2; Volume: 0.8 m3; Shell side pressure: 0.6 MPa; Tube side pressure: 8.9 MPa; Pressure test pressure: 0.4 MPa; Operating pressure: 8.0 MPa; Maximum allowable pressure: 0.75 MPa; Operating temperature: 40°C; Maximum temperature: 132°C; Medium: Cooling water; CO2; Baffle spacing: 100 mm; Net weight: 2404 Kg. 2. Buffers: These are used to reduce the speed of the pulsating gas as it enters the buffer, thereby enabling a steady flow of gas to be output. This helps to reduce compressor vibration, lower power consumption, and prevent accidents caused by loose connections. Specifications: Part, Grade, Category; External Length, Outer Diameter, Inner Diameter, Volume; Gas Inlet Pipe, Gas Outlet Pipe; Operating Pressure, Operating Temperature.
Type 1 with one inlet: 4060 mm, 1212 mm, 1200 mm, 3.78 m³; PN2.0/DN450, PN1.0/DN450; 0.02 MPa, 40°C.
Type 1 with one outlet: 4490 mm, 1012 mm, 1000 mm, 3 m³; PN1.0/DN450, PN2.0/DN300; 0.25 MPa, 136°C.
Type 1 with two inlets: 3190 mm, 812 mm, 800 mm, 1.33 m³; PN2.0/DN250, PN1.6/DN250; 0.25 MPa, 40°C.
Type 2 with two outlets: 3150 mm, 816 mm, 800 mm, 1.33 m³; Pg1.6/Dg250, Pg2.0/Dg200; 0.95 MPa, 160°C.
Type 1 with three inlets: 2265 mm, 562 mm, 550 mm, 0.43 m³; PN2.0/DN200, PN4.0/DN200; 0.95 MPa, 40°C.
Type 2 with three outlets: 2265 mm, 570 mm, 550 mm, 0.43 m³; PN4.0/DN200, PN5.0/DN150; 2.8 MPa, 160°C.
Type 2 with four inlets, spherical shape: 670 mm, 650 mm, 0.144 m³; PN5.0/DN150, PN10.0/DN150; 2.8 MPa, 40°C.
Type 2 with four outlets, spherical shape: 690 mm, 650 mm, 0.144 m³; PN10.0/DN150, PN10.0/DN100; 8.0 MPa, 132°C.

3. Separator: After the gas is pressurized and cooled, the oil mist and water vapor contained in it cool down and turn into liquid droplets. Since liquids are incompressible, they can damage the cylinders if they enter them; therefore, a separator is needed to remove these liquids. Some categories: Shape, Outer diameter, Inner diameter, Volume, Air inlet pipe, Air outlet pipe, Operating pressure, Specification grade. Grade 1: Category 1 – 4100 mm, 912 mm, 900 mm, 2.1 m³; PN2.0/DN250, PN2.0/DN250, 0.25 MPa. Grade 2: Category 1 – 2960 mm, 512 mm, 500 mm, 0.47 m³; PN2.0/DN200, PN2.0/DN200, 0.95 MPa. Grade 3: Category 2 – 2170 mm, 366 mm, 350 mm, 0.16 m³; PN5.0/DN150, PN5.0/DN150, 2.8 MPa. Grade 4: Category 2 – 1980 mm, 273 mm, 245 mm, 0.07 m³; PN10.0/DN100, PN10.0/DN100, 8.0 MPa. 4. Fuel tank: The fuel tank has a volume of 1.6 m³. In the middle of the tank, on the return oil side, there is a double-layer overflow orifice plate that divides the tank into a return oil side and an oil outlet side. a) Oil return side: The oil used by the moving parts of the compressor enters the oil tank through the oil return main pipe, at the upper part of the oil return side; it passes through a coarse filter as it enters the upper part of the tank, and then reaches the oil outlet side via a double-layer overflow orifice plate. At the bottom of the return oil side, a heater is installed for use in winter, to prevent the oil circulation pump motor from being overloaded and damaged due to high oil viscosity, as well as to avoid poor mechanical lubrication resulting from high viscosity, which could damage the moving parts of the machinery. b) Oil outlet side: The oil is pressurized by the circulation oil pump and then sent to various lubrication components via an oil cooler and an oil filter. The oil pump outlet line is equipped with a safety valve; when the oil pressure is high, the oil flows back to the tank through the return line. c. Oil cooler (horizontal, baffle-type cooler): The cooling water in the oil cooler flows inside the tubes, while the pressurized oil flows between the tubes. After heat exchange in both co-current and counter-current modes with the water via the baffles, the oil is sent to the oil filter. Nominal pressure MPa Heat exchange area Oil inlet pipe Oil outlet pipe Water inlet pipe Water outlet pipe 0.63 8m2 DN40 Pg6 /Dg80 DN32 DN32 21. Oil filter: Can be used interchangeably to remove internal oil contaminants on a regular basis. The clean oil at the filter outlet is distributed to various lubrication points through oil pipes. The rated flow rate of the double-tube filter is 12 m³/h, with a mesh count of 508; the maximum operating pressure is 0.8 MPa. Chapter 6: Abnormal Conditions and Their Solutions. Sequence Number, Fault, Symptoms, Causes, Solutions: 1. Power outage – The machine stops automatically, and the current reading is 0. Electrical fault; handle as an emergency stop situation. 2. Water supply interruption – The temperature of the gas behind each cooler rises sharply, and the water pressure drops. This can be caused by a problem with the water supply or broken pipes, or by a detached valve seat. Handle as an emergency stop situation. 3. High gas temperature – The inlet and outlet temperatures rise significantly or exceed the normal range. Possible causes include high ambient temperature, leaking gas valves, high coolant temperature, low coolant pressure, poor cooling efficiency, high compression ratio, or reduced heat exchange area. Solutions: Add water to lower the temperature; adjust the compression ratio; replace the gas valves; contact the water supply provider to increase pressure; raise the coolant pressure to lower the temperature and flush the coolers; adjust the compression ratio again; flush the water jackets of the cylinders. 4. High water temperature – The temperature of the return water rises significantly or exceeds the normal range, the inlet temperature increases, the return pipe heats up, and the water supply pump stops working. Possible causes include a valve that isn’t fully open, low water pressure and flow rate, blocked pipes with increased resistance, scaling or blockages in the coolers, excessive scaling in the cylinder water jackets, a detached valve seat, high ambient temperature, or internal leaks/air pockets in the coolers. Solutions: Open the main return water valve; contact the water supply provider to increase pressure and flow rate; clean the pipes to reduce resistance; use nitrogen to flush the coolers; flush the water jackets of the cylinders; replace the main return water valve; replace the internal components of the coolers if necessary to eliminate air pockets; turn on the fan for water circulation to increase the amount of cold water in the tank. 5. High oil temperature – The temperature of the circulating oil rises significantly or exceeds the normal range, and the return oil pipe heats up. Possible causes include poor cooling performance of the oil cooler, a valve that’s closed too tightly or has a detached seat, blocked or leaking pipes, poor oil quality, or an excessively long preheating time for the oil tank. 5. Inappropriate oil viscosity 1. Stop the machine and clean the oil cooler. 2. Check the valves of the oil cooler. 3. Check the amount of cooling water available and whether there is a water supply issue. 4. Replace the lubricating oil. High temperature of the bearing shells: A significant increase in bearing shell temperature or overheating, along with abnormal noises. 1. The bearing shells are installed too tightly. 2. The contact surface of the bearing shells is not evenly stressed, resulting in localized stress or uneven wear. 3. The oil supply valve is open to a small degree, causing blockages in the oil circuit. 4. Poor oil quality, high oil temperature, and low oil pressure. 1. Stop the machine and replace the bearing shells. 2. Stop the machine for inspection; check the valves of the oil cooler, increase the opening of the oil supply valve, and clear any blockages in the oil circuit. 3. Replace the oil with fresh oil to increase oil pressure. 4. Use external cooling water for the oil cooler to lower the oil temperature. 5. Check the motor bearing shells for damage caused by oil issues. 7. High temperature of the packing: An increase in packing temperature, along with the appearance of smoke, and an increase in the temperature of the packing cooling water. 1. Insufficient oil supply or interruption in the oil supply. 2. The packing rings are worn out. 3. The spring used to compress the sealing ring is broken. 4. The piston rod is worn unevenly. 5. The packing is installed incorrectly. 6. Low cooling water pressure, leaks or blockages in the water pipes, and small openings in the water supply and return valves. 1. Increase the oil supply and replace the damaged packing. 2. Replace the spring. 3. Adjust the piston rings. 4. Realign the packing. 5. Increase the cooling water pressure, open the water supply and return valves wider, and clear any blockages in the pipes. 8. High gas pressure: High pressure in certain sections, obstruction in subsequent sections, valve leaks, and gas leakage. Reduce the resistance, replace the valves, and prevent gas leakage. 9. High oil pressure: An increase in circulating oil pressure, leading to increased leaks. 1. The bypass valve is not adjusted properly. 2. The filter screen of the oil filter is clogged. 3. Insufficient oil return volume, with blockages in the oil return pipes. 4. The oil return valve is open to a small degree or its valve seat has come loose. 1. Adjust the bypass valve. 2. Replace the filter screen. 3. Increase the oil return volume, clean the oil pipes, and replace the oil return valve. 10. High water pressure: An increase in circulating water pressure, leading to increased leaks. 1. Increase the water pressure supply. 2. Low amount of water returning through the coolers in sections II, III, and IV. 3. Blockage in the return pipe; valve opening is too small. 4. The valve head of the return valve has fallen off. 5. One unit has stopped operating, resulting in reduced water consumption. 6. Water supply pressure has increased. 7. One unit has stopped operating, resulting in reduced water consumption. 1. Contact the water supply department for assistance. 2. Replace the coolers to increase the amount of water returning. 3. Clean the return pipeline. 4. Open the return valve fully. 5. Replace the return valve. 6. Contact the water supply department for assistance. 11. Motor on fire; there is a burnt smell or smoke. 1. Poor insulation in the motor causing a short circuit. 2. Excessively small gap between the stator and rotor, or something falling in and causing a short circuit. Cut off the power supply, stop the machine urgently, use a dry powder fire extinguisher to put out the fire, and call the fire department. 12. Cylinders contain water; the cylinder body vibrates violently, along with a dull noise; outlet temperature drops and current increases. 1. Water has not been completely drained from the separator. 2. The inner tubes of the cooler are cracked. 3. Severe water contamination in the cylinders. Stop the machine urgently and address the issue. 13. Oil injection pump stops working or fails to inject oil at certain points. Oil injection pump stops working; oil pipes heat up. 1. Problems with the oil injection pump motor. 2. Blocked oil pipes. 3. Worn plungers causing oil leakage. 4. Damaged check valves. 1. Address the issue through electrical repairs. 2. Stop the machine. 3. Fix it using mechanical methods. 14. Abnormal knocking sounds are heard during operation; the cylinder body vibrates violently, along with a dull noise; inlet and outlet temperatures drop and current increases. 1. Cylinders contain water. 2. Debris such as valve plates falls into the cylinders. 3. Loose connections or excessive gaps in moving parts, such as loose crosshead nuts or piston caps. Stop the machine urgently. 15. Low suction pressure at the first stage; the pressure gauge shows a lower reading. 1. Faulty pressure gauge. 2. Blocked or damaged instrument tubing. 3. Reduced flow rate in the low-temperature methanol scrubber. 1. Contact the instrumentation department for assistance. 2. Stop the machine. 3. Contact the low-temperature methanol scrubber and use a one-way valve to maintain pressure. 16. Abnormal changes in gas pressure; the pressure gauge pointer fluctuates suddenly. 1. Severe leaks in the pipes. 2. Severely damaged gas valves. 3. Air leakage due to expansion rings. 4. Faulty pressure gauge. 1. Stop the machine. 2. Replace the gas valves. 3. Replace the pressure gauge or check the opening of the instrument valves. 17. Abnormal changes in temperature across various sections; temperature rises or falls suddenly. 1. Damaged inlet and outlet valves. 2. Incorrect compression ratio. 3. Low water pressure. 4. Cylinders contain water. 5. Inaccurate temperature readings. 1. Adjust the compression ratio to normal levels. 2. Stop the machine. 3. Increase water pressure. 4. Stop the machine and have the instrumentation checked. 18. Air leakage from the valve stem; carbon dioxide gas escapes from the valve. The packing lacks oil or is not properly compressed. 1. Production can continue if there is only slight leakage; be cautious. 2. Add oil and tighten the packing. 3. Stop the machine if the leakage is severe. 19. Gas valve leakage; temperature rises, pressure increases in the preceding section, and decreases in the following section. 1. Damaged springs or valve plates. 2. Springs or valve plates are stuck in place. 3. Poor installation leading to leakage at the sealing surface. 1. Continue production if there is only slight leakage. 2. Stop the machine and replace the gas valve if the leakage is severe. 20. Low oil pressure; the oil pressure gauge shows a lower reading. 1. Low oil level in the tank, low opening of the oil pump’s inlet and outlet valves, and excessive vibration of the bypass valve. 2. Faulty oil pump, high resistance in the oil filter. 3. Poor cooling effect of the oil cooler leads to a decrease in oil viscosity. 4. Breakage of oil pipes and pressure gauge tubes. 5. Failure of the pressure gauge. 1. Top up the oil tank. 2. Adjust the opening degrees of the inlet and outlet valves of the oil pump. 3. Close the short-circuit valve. 4. Overhaul the oil pump. 5. Clean the oil filter and replace the filter element. 6. Clean the oil cooler to increase the heat exchange area. 7. Replace the pressure gauge; shut down the pipeline. Low water pressure: the pressure gauge shows a decrease in reading. Insufficient water supply, broken water supply pipeline, valve not opened fully, or problem with the pressure gauge. Contact the water supplier to increase the water flow and raise the pressure, open the valve more fully, replace the gauge, and inspect the water supply pipeline. 22. Low gas pressure: the pressure gauge indicates a low reading. 1. Low gas pressure. 2. Leakage in the gas valve causing low pressure in this section. 3. Increased demand for gas for vaporization. 4. Malfunctioning safety valve, bypass valve, internal leaks, or faulty pressure gauge. 1. Contact the low-temperature methanol washing unit to increase the gas flow. 2. Replace the gas valve. 3. Replace or repair the leaking valve, and replace the pressure gauge. 23. Low gas temperature: low temperature of the gas results in a smaller compression ratio, liquid in the cylinder, and a sudden drop in temperature. Check for accumulated water and adjust the compression ratio. 24-cylinder engine overheating; the cylinder block is hot to the touch. 1. Insufficient cooling water. 2. Excessive scaling in the cylinder water jackets. 3. Abnormal piston operation and issues with the piston rings. 4. Insufficient amount of lubricating oil 5. Settlement of the foundation 6. Valve leakage 7. Vaporization of water in the cylinder liner 1. Increase the amount of water used 2. Clean the cylinder liner 3. Check the piston and expansion rings 4. Increase the oil supply volume 5. Inspect the foundation and take corrective actions 6. Replace the valves 7. Remove water vapor from the cylinder liner. Chapter 7: Safe Production I. Routine Inspection System for Work Posts Inspection route: Control room → Local instrument panel → Oil injection pump → Crankshaft turning device → Second-stage cylinder group and buffer → Third-stage cylinder group and buffer → Motor and motor bearing fluid levels → Fourth-stage cylinder group and buffer → First-stage cylinder group and buffer → Light oil station → First-stage cooler and separator → Second-stage cooler and separator → Third-stage cooler and separator → Fourth-stage cooler and separator. Inspection frequency: Under normal circumstances, inspections are carried out once per hour. Inspection items: 1. Whether the suction and exhaust pressures and temperatures at all levels are normal. 2. Are the temperatures of the motor bearings, stator, and main shaft bearings normal, and is the motor current operating properly? 3. Check whether the operating components such as the crankshaft, connecting rods, crossheads, and piston rods are functioning properly. 4. Check whether the packing and oil-scraping rings in each section are operating normally. 5. Are the lubricating oil pressure, temperature, oil filter pressure difference, oil tank level, and motor bearing oil level within normal ranges? 6. Check the pressure and temperature of the return cooling water; observe the flow of the cooling water through the return water sight glass, as well as whether there is any gas formation in the various cooling water pipelines. 7. Leakage of water, oil, or air from various connection flanges, oil seals, cylinder heads, pipes, etc ； and the vibration conditions of each pipeline. 8. Operation status of inlet and outlet valves in each section. 9. High liquid level discharge from the separators in each section. III. Safety Production Procedures for the Position 1. Fires and smoking are prohibited at this position. 2. The pressure and temperature of the equipment must not exceed the specified limits; the use of substandard lubricants is prohibited. 3. The system’s pressure increase and decrease should be done slowly, in strict accordance with the specified rates, to prevent damage to the equipment or explosions due to overpressure. 4. Prevent suffocation caused by excessive carbon dioxide levels in the factory building. 5. In the event of an accident in other positions, handle one’s own tasks first, then follow the instructions given by the team leader and dispatcher; do not wander around randomly. IV. Responsibilities of Position Staff 1. Strictly enforce process discipline and keep all process parameters within the specified ranges. The operating conditions and methods must not be changed without approval. 2. Abide by labor discipline; do not engage in activities unrelated to production during working hours. Do not leave your post without the permission of the team leader, and if you must leave with permission, someone must take your place. 3. Keep accurate records; all data must be precise and reliable, with neat handwriting. Records shall not be altered or scribbled on, and reports should be clean and well-presented. 4. Strengthen routine inspections and carry them out in accordance with the inspection system specified in the operating procedures; whenever any issues are detected, report them to the team leader immediately so that they can be addressed promptly. 5. Strengthen the maintenance of equipment to improve its integrity; unused equipment should be rotated at least three times per shift. Responsible for the cleaning, lubrication, antifreeze treatment, and minor repairs as necessary for the equipment, pipelines, instruments, tools, lighting, fire protection systems, protective gear, buildings, etc. under his/her responsibility. One hour before each shift change, thorough cleaning of the own workstation should be carried out to ensure civilized production practices. V. Shift Handover System 1. Arrive at the post 20 minutes in advance to check the process conditions, equipment status, tools available at the post, safety equipment, fire-fighting equipment, electrical instruments, as well as the level of cleanliness and order. 2. The person handing over the shift is responsible for providing detailed answers and resolving any issues raised by the person taking over the shift. Without the consent of the person taking over, the person handing over shall not leave their post; if necessary, the team leaders of both parties should discuss and find a solution. 3. Both the delivering and receiving parties should earnestly achieve “five deliveries and four satisfactions”. “The “five communications” refer to communicating superior instructions ； Status of equipment and instruments operation and maintenance ； Performance of target delivery ； Reasons for abnormal transmission and handling measures ； Provide tools and protective equipment. “The “four satisfactions” refer to satisfaction with the process parameters ； The operation is smooth and satisfactory ； Satisfaction with civilized production ； Satisfied with equipment maintenance. After both parties confirm that there are no issues, they sign the record, and the handover is complete. 4. When there is no one to take over, the person handing over the shift must report to the shift leader promptly; they may leave only after an alternative has been arranged. Leaving without permission is not allowed. 5. In the event of production fluctuations during the handover process, the person handing over the shift should take the lead, with assistance from the person taking over, to handle the situation promptly; the person handing over may leave only after obtaining the consent of the person taking over. 6. After taking over, conduct a thorough and careful inspection of your assigned area, and contact the relevant parties to address any issues found promptly. VI. Equipment Maintenance System 1. Strictly control all process parameters; operation under conditions of excessive temperature, pressure, or load is strictly prohibited. 2. Lubricant should be applied to the operating equipment at regular intervals, in designated locations, in specified quantities, and by designated personnel. 3. Ensure that the backup equipment is in good working condition, and the pumps should be equipped with protective covers. 4. Apply rust preventive oil to the exposed valve stems regularly to ensure smooth and reliable operation. 5. Instruments, electrical equipment, fire protection systems, and safety devices must not be tampered with, adjusted, or used for other purposes without permission; any issues detected should be reported to the relevant authorities promptly for handling. 6. For equipment and containers that are flammable, explosive, subject to high or low temperatures or pressures, strict oil management procedures must be followed to ensure that the oil grade is clearly indicated and that its quality is guaranteed. 7. For the equipment associated with the position, one should possess: three understandings and four skills. Three understandings: understanding the production principles, understanding the process flow, and understanding the equipment structure. Four skills: knowing how to use, maintain, inspect, and troubleshoot. VII. Poison prevention knowledge: The main poisons that may be present in the production of methanol plants include ； Carbon monoxide (CO), ammonia (NH3), hydrogen sulfide (H2S), as well as CO2 and N2, etc. (1) General knowledge about poisons: Poisons refer to certain substances that, when they enter the human body, can, through physical and chemical processes, disrupt the normal physiological functions in bodily tissues, thereby causing pathological conditions in the body. This substance is called a poison. Diseases caused by poisons are called poisoning. Classification of poisons: The chemical structure of poisons is divided into organic types (such as methanol) and inorganic types such as ammonia ； Based on the form of the toxin, they are classified into gases (such as hydrogen sulfide), liquids (such as nitric acid), solids (such as silica dust SiO2), and mist forms (such as sulfuric acid mist) ； Based on their toxicological effects, they are classified as irritants (such as chlorine Cl2), asphyxiants (such as nitrogen), **toxins (such as ethanol), pyrogenic substances (such as zinc oxide), corrosives (such as sulfuric acid), and sensitizers (such as para-phenylenediamine). The routes by which toxins enter the body are: the respiratory tract, the skin, and the digestive tract. (II) Characteristics and Protection Against Common Toxins in Methanol Production 1. Carbon Monoxide (CO) Carbon monoxide is a colorless, odorless, and non-irritating gas. Therefore, it is difficult to detect its presence, and the harm it causes is significant. Therefore, leaks in ammonia synthesis production must be given serious attention, and all leakage points must be eliminated, as the leaked gas may contain large amounts of CO. Additionally, the vent gas also contains a large amount of CO. Therefore, the air should be released at a high altitude away from the ground, or through combustion. After entering the body through the respiratory tract, carbon monoxide reaches the blood via the alveoli, where it binds reversibly to hemoglobin in the blood to form carboxyhemoglobin, thereby causing a deficiency in oxygen intake, leading to hypoxia and suffocation poisoning. The maximum allowable concentration of carbon monoxide in the air at the workplace is 30 mg/m3. 2. Carbon dioxide (CO2): Low concentrations of CO2 have an excitatory effect on the respiratory center. High concentrations have a paralyzing effect due to their significant toxicity. High concentrations of CO2 can directly cause death by asphyxiation. Therefore, production sites that generate CO2 must be kept well-ventilated. Before entering enclosed equipment, containers, sewers, etc., a safety analysis must be conducted first, and entry is permitted only after it is approved. 3. Hydrogen sulfide (H2S): H2S is a colorless gas with an odor similar to that of rotten eggs. The rotten egg smell of H2S increases as its concentration rises, but once the concentration exceeds around 10 mg/m3, further increases in concentration result in a decrease in this rotten egg odor. As a result, the concentration of H2S that can cause poisoning is not easily detected by people. H2S is a potent neurotoxin that has a significant irritant effect on mucous membranes. When high concentrations are reached in the body, it first has an excitatory effect on the respiratory center and spinal cord centers, before shifting to an inhibitory effect ； At high concentrations, it triggers a reflex in the carotid sinus that causes breathing to stop ； At higher concentrations, it can also directly paralyze the respiratory center, causing immediate asphyxiation. The maximum allowable concentration of H2S in the workplace air is 10 mg/m3. 4. Ammonia (NH3) Ammonia is a colorless gas with a strongly irritating odor. The toxicity of ammonia to humans mainly lies in its irritant and corrosive effects on the upper respiratory tract. At high concentrations (such as in liquid ammonia), direct contact can cause alkaline chemical burns, leading to dissolving necrosis of the tissues. It can also damage the deep alveoli in the respiratory tract, resulting in chemical bronchitis, pneumonia, and pulmonary edema. Since the product of ammonia synthesis is liquid ammonia, special care must be taken to prevent ammonia leaks. In the event of a significant leak, one must wear a gas mask and an oxygen respirator before entering the site to cut off the source of ammonia or shut down the equipment in order to prevent the accident from spreading. The maximum allowable concentration of ammonia in the air at the work site is 30 mg/m3. 5. Nitrogen (N2) Nitrogen is a colorless, odorless inert gas that neither burns nor supports combustion. Inhaling high concentrations of nitrogen leads to a state of hypoxia. When breathing pure nitrogen, nitrogen asphyxiation causes immediate loss of consciousness, followed by death from asphyxiation. Therefore, when working inside equipment that has been purged with nitrogen, a safety analysis must be conducted; work can only proceed when the oxygen level is between 19% and 22%, and there must be someone present to supervise. (III) Handling of poisoning incidents: In the event of any poisoning incident, the first step is to quickly move the poisoned person away from the toxic area to a place with fresh air. Those who are severely poisoned should receive immediate first aid on the spot, after which emergency services should be called to transport them to the hospital for further treatment.

Very useful information, thank you so much!