[Request for Upload Summary] PSA Position Operating Procedures (Production Plan)

Pressure swing adsorption decarburization cleaning and purging plan: I. Purging of the hydraulic system 1. Before installation, each pipeline in the hydraulic system is cleaned using acid treatment to ensure there are no foreign objects or dust accumulation. 2. After installation, use compressed air to blow clean each pipe in the hydraulic system one by one. Following the flow path of the oil, the connections to devices such as the oil pump station tank, oil pumps, solenoid valve stations, hydraulic valve cylinders, and accumulators are disconnected one by one. Compressed air is used to blow out debris from each pipe, while a wooden hammer is used to strike the pipes in order to dislodge any impurities on their inner walls. 3. Add diesel and turn on the oil pump to clean the entire system. Finally, drain the diesel, and clean out the diesel, debris, and grease from the fuel tank, cylinders, hoses, and pipes. 4. Add anti-wear hydraulic oil, start the oil pump for a test run, and observe the operation of each valve; address any issues that arise promptly. After the valves have been operating properly for 48 hours, drain the oil from the system for filtering, and clean the fuel tank, cylinders, hoses, and pipes. 5. Finally, add anti-wear hydraulic oil, and the hydraulic system will enter a normal standby state; continue to monitor the operation of the valves during operation. II. Purging of the process system: 1. Before purging, it is necessary to check that all equipment pipes, flanges, valves, instruments, safety devices, etc. are present, and that the flow path is unobstructed, to ensure compliance with production safety and process requirements. Before purging, remove the relevant pressure gauges from the system; first purge the pressure gauge pipelines and equipment together, and then use the pressure stored in each tower to purge the pipelines in sections. 2. Prepare a wooden hammer, tin, white cloth, or white paint to check whether the cleaning is thorough. 3. The purging process must be halted only after it has been approved by the purging test team. Requirements for cleaning: 1. The overall cleaning process must ensure that rust, slag, and other debris are not introduced into the equipment, in order to prevent blockages of the drain valves and damage to the spools of the hydraulic control valves. Remove the blind plates or short pipes from each main pipe and install baffles. 2. Detailed records must be kept for the cleaning of each device and each pipe section. After cleaning the previous section, connect the flange and short pipe, then prepare to clean the next section. 3. Blow clean using compressed air as the medium ； When cleaning, use a wooden hammer to strike the pipes and welds to ensure that there are no impurities such as iron filings or slag. 4. In the process of purging, it is necessary to stop the purging in case of special circumstances or when safety is at risk. 5. Purging pressure: ≤0.6 MPa. Purging steps: 1. Start the oil pump; close all programmable valves and manual valves. 2. Use an air compressor to inflate Tower A and build up pressure, raising it to 0.3 Mpa–0.5 Mpa. 3. Blow out each main pipe, remove the blind flanges at both ends of each main pipe, and use manual control to open the inlet valves for Tower A as well as the product gas valves, in order to blow out each main pipe. 4. Using the same method, pressurize the other towers to purge each main pipe; when purging with Tower J, install a blind flange at the western end of the main pipe and remove the blind flange at the eastern end, then carry out a final thorough purge of all the main pipes. 5. After cleaning the main pipe is complete, install a blind flange on it. 6. Apply pressure to Tower A, and sequentially purge the branch pipes connected to each main pipe. When connecting each branch pipe to the equipment, the equipment flange should be removed; after cleaning is complete, the flange should be reinstalled. 7. The cleaning of each branch pipe must be thorough, with no dead corners left. 8. When cleaning each pipeline, use a wooden hammer to tap on areas such as welded pipe connections; pay extra attention to tapping the welds to ensure that all slag, rust, and other debris are thoroughly removed. 9. After cleaning is complete, install the flanges and blind plates in all areas. Get ready for pressure testing. This post was last edited by *aoye613 on 2009-3-8 20:17]

Original startup plan for pressure swing adsorption carbon removal I. Preparatory work before the first startup After the installation of the unit is complete and the automatic control system has been thoroughly tested, the control system is used to purge the unit and conduct a leak test. Once these tests are successful, it is checked whether the screens inside the adsorption towers are installed properly; if so, the adsorbent is then added. However, since the feed gas, product gas, and purge gas in this device all contain large amounts of hydrogen, if oxygen in the system is not removed in advance, explosive and combustion accidents can easily occur due to the formation of explosive substances at the beginning of operation. Therefore, before feeding in the feed gas, it is necessary to evacuate the entire device using a vacuum pump and purge the whole system with an inert gas to keep the oxygen content in the system below 0.5%. After all the above work is completed, all valves should be closed. 1. Preparatory work before starting up the control system 1.1 Inspection of the control system: The device’s control system uses electric type III control instruments. The field transmitter unit is connected via wires. Therefore, after installation, first check for any wiring errors, and then apply the power signal to verify that the zero and full-scale positions of all instruments are correct. Then, a no-load simulation test is conducted on the entire system, including the manual control system, to check whether the actions of the actuators are correct. 1.2 Check the travel of the actuator (control valve): Apply a 4–20mA signal to the control valve to verify that it moves through its full range. 1.3 Check the microcomputer control function: After the main signals of the microcomputer control system are converted through multiple switching stations to liquid signals, these signals are used to operate the various programmable valves on site. Once the system is installed as required, it is first necessary to check for any wiring errors; thereafter, the dynamic performance of the system should be checked following the steps below ； 1.3.1 To enter the main process control screen, first, in the process mode with Tower 10 in operation, set the time for each step as desired according to its timing table; the program will then start executing from the initial state, checking whether the functions for reset, pause, stepping, and time setting are all working properly. 1.3.2 Perform no-load function testing on the entire programmable control system (control system – multiplex switching station – programmable valve). Send signals to the on-site programmable valves, and use the pause button to check whether each step of the system operates properly. If everything is functioning correctly, release the pause button; then press the step button, execute one step of the program, and pause again to check the system’s operation before releasing the pause button. This repeats over and over until all the operational steps for the 10 adsorption towers have been completed once. 1.3.3 Check the switching system: Set any switching mode of 10 towers to 8 towers, and verify whether there are significant changes in the operating procedures of the adsorption towers during the switching process, that is, whether a tower with higher pressure undergoes direct reverse discharge or evacuation, etc ； Once this inspection is complete, switch the 8-tower process back to 10-tower operation, and similarly check whether the switching steps are appropriate ； Then set another 10-to-8 switching method for testing… ； This process of checking is repeated until all switching methods have been checked. 1.3.4 Enter the self-adjusting system parameter setup screen, set all parameters as indicated, and select any one of the self-adjusting control methods to conduct a test ； Vary parameters such as flow rate, CO2 content in the purified gas, and adsorption pressure, and check whether other parameters like time and valve opening degree also change. Whether the trend of change is correct, etc. Finally, turn off the computer and the 24V power supply, and check to ensure that all programmable valves are closed. 1.4 Check the flow rate and calculate the system; calibrate and inspect it in accordance with the flow meter’s instruction manual. 1.5 CO2 analyzer and vacuum pump: When the analyzer is fed with CO2 standard gas, the microcomputer displays a value identical to the concentration of the CO2 standard gas. When a small amount of air is added to the sample, the CO2 level displayed on the microcomputer used for analysis should decrease. If it is not the case mentioned above, it indicates that there is an error in the analyzer’s wiring, and the wiring needs to be checked. While the above work is being carried out, the vacuum pump should also be inspected and tested to ensure it is in proper standby condition. II. Feeding, startup, and operation: After the inspection and debugging of the process and instrument control systems of the entire unit, as well as after evacuating the unit with a vacuum pump and replacing the air with an inert gas. The unit is ready to start operation at any time. 2.1 Preparatory work before startup 2.1.1 Setting of process valves: Open the stop valves located before and after the control valve, as well as the upstream valves before the safety valves. Open all the isolation valves at the base of the pressure gauges or pressure transmitters, and open the inlet and outlet stop valves of the vacuum pump. 2.1.2 Settings of the control system (see table below) Control system code Control method Code of the control valve Valve position setting HC-101 Manual HV-101 1/3 PIC-102 Manual PV-101 1/3 2.1.3 Starting up the microcomputer-based programming system Turn on the power of the microcomputer-based programming system, access the programming interface, and set the time for each step according to the requirements for normal operation of the process. (The self-adjusting system is not activated at this time), and it is set to self-check or manual mode. 2.2 Startup 2.2.1 Put the microcomputer-controlled system into automatic operation mode, and slowly open the raw material gas inlet valve V-101 to feed material into the adsorption tower. Since the flow meter does not provide accurate readings when the amount of material fed is small, the control of the flow rate should be set such that the adsorption pressure increases at a rate of 0.2 Mpa per minute, in order to prevent excessive flow. At the same time, open the inlet valves of the corresponding vacuum pumps and start these pumps in accordance with their normal operating procedures ； When the adsorption pressure rises to 0.1 Mpa, the programmable control system switches once by pressing the step button; this process is repeated several times, and at this point the adsorption tower is being purged with feed gas ； Thereafter, whenever the pressure in the adsorption tower increases by 0.1–0.2 Mpa, the programmable control system will trigger a stepwise switch, continuing until the desired adsorption pressure is reached. During this pressure increase process, it is important to open the manual reverse release valve immediately if the pressure drops below atmospheric level; At the same time, attention should be paid to adjusting the flow rate for pressure increase and the flow rate for gas release. 2.2.2 When the adsorption pressure rises to the rated operating pressure, PICA-102 is put into automatic control mode; valve V101 is gradually opened to increase the flow rate of the feed gas. At this point, the flow rate reaches about 1/4 to 1/2 of the rated operating flow rate. The unqualified purified gas is temporarily sent through valve V140 to the exhaust main line VT101 for discharge. 2.2.3 When the adsorption pressure rises to (0.8 Mpa) of the operating pressure, and after operating under this pressure for 4–5 cycles, the CO2 analysis system for the purified gas, ARA-101, can be activated. The sample gas flow rate through the instrument should be set to the designated value; when the CO2 concentration in the gas approaches the required level, it indicates that the purified gas is nearly ready. At this point, valve V140 can be closed, and the manual output valve for the product gas can be opened, allowing the purified gas to be sent outside the system. 2.2.4 During the execution of these operations, PV102 should be adjusted continuously so that the flow rate of the raw gas gradually approaches the rated value. At the same time, it is necessary to adjust the final filling control valve and the exhaust valve accordingly, so that the entire system ends up in a coordinated and stable operating state. At this point, the device can be set to automatic operation, with the relevant parameters configured as well. The initial driving phase requires a longer period for parameter adjustment; once the parameters are adjusted, however, The vast majority of parameters do not need to be changed, allowing the device to operate in fully automatic mode.

Safety Operating Procedures for Pressure Swing Adsorption Carbon Removal 1. Operators must follow the operation manual; all new employees must receive safety training and instruction on operating procedures before they can start working. In actual operation, those who have not passed the technical and procedural examinations are not allowed to perform operations independently. 2. Operators must be properly dressed while at work, and it is prohibited to bring flammable or explosive items into the site. Strictly carry out shift handovers, conduct thorough inspections, strictly control process parameters, and adhere strictly to operating procedures and relevant regulations. 3. It is strictly prohibited to carry out any repair work, welding, screw tightening, etc., until the pressure in the equipment has been released; it is also forbidden to use metal tools to strike the equipment. 4. The pressure gauge used on the equipment must be inspected and sealed with a lead seal; it must not be used if the gauge pointer does not return to zero or if the error exceeds the allowable range for its grade. The pressure gauge must be inspected and sealed each year. 5. Smoking and welding are strictly prohibited within the area of this device. Whenever maintenance work on containers or pipelines that contain explosive or flammable gases is required, approval must first be obtained from the factory’s safety department and the relevant workshop. The area in question must first be purged with nitrogen, and after on-site analysis confirms that it is safe and appropriate safety measures have been taken, a welding permit can be issued before work can begin. Welding is strictly forbidden in cases where no welding permit has been granted, when the area is not isolated from the production system, when proper cleaning and purging have not been carried out, when flammable materials in the vicinity have not been removed, when welding analysis is not conducted on time, when no fire prevention measures are in place, or when there is no one to supervise the work. 6. Ensure the airtightness of equipment, pipelines, and valves; after maintenance, thorough leak checks must be carried out, and operation can only commence once everything is found to be in order. Be careful to prevent gas leaks at all times during use. 7. In the event of a fault in the instrumentation system, it should be repaired by instrumentation technicians, who must work closely in conjunction with process operators. When restarting after parking for maintenance, attention must be paid to the pressure inside the adsorption tower to prevent high-pressure backflow. 8. Strictly control process parameters to prevent overheating and overpressure. 9. Strictly implement the routine inspection system to ensure the proper operation of equipment and pipelines.

Chapter 1: Job Responsibilities – PSA–CO2 Unit Responsibilities: 1. The shift gas supplied from the reformer is separated from liquids and impurities using a gas-water separator, after which it enters the adsorption towers of the pressure swing adsorption system. Under programmed control, the adsorbent in each tower carries out adsorption and desorption processes, thereby removing CO2 and small amounts of H2S from the shift gas. The resulting purified gas is further desulfurized using a sophisticated desulfurization system before being sent to the synthesis process. 2. The separated CO2 is concentrated to over 96% and then sent back to the CO2 gas tank via reverse flow. For use with urea. 3. Adjust various process parameters reasonably to optimize production and reduce consumption.

Chapter 2: Working Principle of PSA – CO2 Working Principle: Basic principle of pressure swing adsorption for carbon removal: The basic principle of pressure swing adsorption is that the adsorbent has different adsorption capacities for the adsorbate at various partial pressures, and it also possesses the ability to selectively adsorb various components of the gas mixture to be separated at a certain pressure. By applying pressure, impurity components in the feed gas are removed through adsorption; by reducing the pressure, these impurities are desorbed, allowing the adsorbent to be regenerated. This system uses silica gel as an adsorbent to selectively adsorb and remove most of the CO2, organic sulfur, etc., from the reformate gas. Multiple adsorption beds are used, with the pressures of the combined adsorption beds being changed cyclically to achieve continuous separation. This system employs a two-stage separation process; the purification stage uses a 26-4-20 pressure equalization technique, which involves 26 columns, with 4 columns in adsorption at any given time, and 20 cycles of pressure equalization. The purification section employs a 11-3-4-3 pressure equalization process, namely 11 adsorption towers, with 3 towers operating for adsorption simultaneously, 4 pressure equalization cycles, and 3 purge cycles. Fully recover the available H2 and N2 from the bed dead space, increase the CO2 concentration in that dead space, and enrich CO2 to over 96% before sending it to the urea CO2 gas tank.

Chapter 3 Process Flow 1. Reformate and purified gas flow: Approximately 25% of the CO2 supplied from the reformer, at a temperature of around 40°C, is sent to the pressure swing adsorption system. After free water is removed using a gas-water separator, it enters the purification adsorption tower column. The gas passes through the beds in the four towers that are all in the adsorption phase, from bottom to top; the gas exiting these towers then proceeds to the purification stage. When the concentration front of the adsorbed CO2 approaches the outlet of the bed, the raw gas inlet valve and the product gas outlet valve of the adsorption tower are closed to stop the adsorption process. The product gas in the dead space of the bed is recovered through twenty pressure equalization steps and released in the opposite direction to the adsorption direction; the easily adsorbed component, CO2, is discharged into the CO2 gas tank, thereby achieving preliminary regeneration of the adsorbent. Part of the purged gas is sent to the CO2 gas holder, while part is vented. Thereafter, the pressure in the adsorption tower is gradually increased to the adsorption pressure to initiate the next adsorption cycle. The intermediate gas exiting the purification adsorption tower contains about 6–8% CO2; it then enters the purification adsorption stage, where it undergoes the same adsorption and desorption processes to further separate the CO2 from this gas. The gas emerging from the purification adsorption stage has a CO2 content of less than 0.25%, and is sent on to the synthesis process. In the purification section, CO2 desorption is achieved through four pressure equalization steps; H2 and N2 from the bed are recovered first, and then the gas resulting from three forward discharges, three reverse discharges, and three purging steps is recovered for use in the purification section.

Chapter 4: Process Parameters
1. Temperature:
- Inlet temperature of circulating water: ≤25°C
- Outlet temperature of circulating water: ≤45°C
- Temperature of circulating oil: ≤45°C
- Temperature of conversion gas: ≤40°C
- Temperature of purified gas: ≤40°C
- Temperature of product gas: ≤40°C

2. Pressure:
- Pressure of conversion gas: ≤2.0 MPa
- Pressure of purified gas: ≤2.0 MPa
- Pressure change rate: ≤0.2 MPa/min
- Pressure of circulating oil: 6.0–7.0 MPa
- CO2 pressure in product gas: ≤0.015 MPa

3. Flow rate:
- Flow rate of conversion gas entering the system: ≤120,000 Nm3/h
- Flow rate of purified gas: ≤87,600 Nm3/h
- Flow rate of CO2 in the regeneration gas: ≤22,600 m3/h

4. Gas composition:
- H2S content in conversion gas: 100 mg/Nm3
- CO2 content in purified gas: ≤0.25%
- H2S content in purified gas: ≤10 mg/Nm3
- CO2 concentration in product gas: ≥96%
- CO2 content in intermediate gas: ≤6%

Safety Operating Procedures for Decarbonization Tasks: 1. Turn on and off the computer in accordance with the established procedures; do not pull the power supply forcefully. Under normal production conditions in a system where the computer is connected to a PLC, it is strictly prohibited to modify the Citect operating procedure. II. In the event of a sudden power outage, first turn off the PLC power supply or the main power supply, then close the outlet flow valve, the inlet valve of the vacuum pump and its water supply valve. After that, close the inlet and outlet valves of the compressor, and open the circuit valve; pay attention to the pressure in the negative pressure tower ； It checks conditions such as whether the hydraulic valve is closed, in order to prevent the valve from failing to close properly, as well as situations where carbonized NH3 water enters or high pressure affects low pressure areas. III. Before starting the machine upon receiving a call, it is necessary to carefully check the status of all valves and switches, as well as to ensure that all equipment is in a ready state for operation. Turn on the computer to verify that the pressures in each tower match the current values. If necessary, be sure to relieve pressure and identify the problem before driving again. When starting a vacuum pump, open valve V7 first, ensure equilibrium on both sides of the vacuum pump, and then close valve V7. IV. All manually operated valves must be closed by clicking when switching to interlocked operation, to prevent accidents during system shutdown. V. Adjust the various time and outlet flow valves in a predictive manner; avoid sudden increases or decreases in flow. The adsorption time per cycle should be adjusted to ≤50 seconds, thereby ensuring stable production and improving the recovery rate of product gas. VI. During normal operation of the system, it is strictly prohibited to open the drain valves on any pipelines where negative pressure may occur, in order to prevent air from entering the system and causing accidents; when the system is shut down for an extended period, all tanks under negative pressure must have their pressure adjusted to positive levels. VII. The soda separator should be drained of waste regularly; if drainage is not carried out in a timely manner and the liquid level becomes too high, the system should be shut down urgently. If the carbon dioxide output exceeds the specified limits, measures such as reducing the flow rate or increasing the operation of vacuum pumps should be taken immediately. The cause of the problem must be identified and resolved before the gas can be sent to the subsequent processing stages.

Prevention of water ingress into the adsorption tower and measures for dealing with it when water does enter. I. Forms of water ingress and their hazards: During startup and shutdown of the decarburization process, water can easily enter the adsorption tower from the main carbonization tower and the fixed auxiliary tower (Tower No. 3). Water from the former enters the adsorption tower through a steam-water separator at the bottom of the tower, while water from the latter enters directly at the top of the tower. During normal production, the ingress of water into the adsorbent can also occur due to untimely discharge of condensate water when changing shifts, or due to untimely drainage from the decarburization gas-water separator and inlet pipes. If the method of starting and stopping the vacuum pump is incorrect, the negative pressure tower will also draw water back into the adsorption tower through pipe #7. Soaking the adsorbent in water permanently destroys its adsorption capacity, rendering it unrecoverable. Ammonia water introduced into the adsorption tower may react with CO2 inside the tower to form crystals that clog the system. II. Preventing water from entering the adsorption tower: a) During normal operation, regularly monitor the liquid level in the steam-water separator, and drain the water accumulated in the steam-water separator and inlet pipes on schedule; if necessary, increase the frequency of drainage. b) When driving, the inlet and outlet valves should be opened slowly to gradually increase pressure. Prevent excessive pressurization from causing carbonized gas to flow back and introduce ammonia into the system. c) After opening the inlet valve each time while driving, the steam-water separator and the inlet pipeline must be drained once. Start with the inlet first and then the outlet, ensuring that the inlet flow is greater than the outlet flow (the manual valve for pre-recycling the outlet also falls under this category). d) In the event of a significant reduction in production or an abrupt shutdown, the flow rate should be reduced accordingly; generally, for every two units whose decarburization outlet flow rate is reduced, the flow rate is decreased by 3000 M³/N. Regulation should continue until the addition and removal of units stabilize, after which normal regulation can be resumed. In the event of a sudden stop or a trip of the compressor, the decarburization system must be stopped immediately, and the inlet and outlet valves (or flow control valves) of this system should be closed to prevent backflow of gas and liquid caused by excessive return gas from the second stage of the compressor. e) In the event that gas leakage occurs simultaneously in one or multiple towers of this system, as well as in valves 1#, 2#, and 7#, the system must be stopped immediately and the main inlet and outlet valves closed, to prevent carbonized gas and liquid from flowing back into the system due to the direct release of gas through valves 1#, 2#, and 7#. f) The correct operating procedures for the vacuum pump; take effective measures promptly if the vacuum pump trips to prevent water from entering the negative pressure tower. III. Criteria for determining the presence of water: 1. A large amount of water is discharged from the steam-water separator or inlet pipe, and water is also being discharged from the tower where adsorption is taking place. 2. There is an ammonia smell inside the outlet pipe (it is rare for water to be present at the outlet; this usually occurs when the gas production volume is low or under other special conditions). 3. The vacuum pump tripped, but the pump inlet valve was not closed in a timely manner, or there were obvious signs of water backflow at the pump inlet. IV. Treatment methods after water ingress: 1. Shut down the system (keep the oil pump running), close the inlet and outlet valves, and activate the steam-water separator, the inlet pipe, as well as the drain systems of the three adsorption towers. 2. Once the system is virtually free of water, start the vacuum pump to evacuate the tower containing water for several hours, continuing until no water vapor remains in the evacuated gas. 3. Turn off the cooling water for the transformed gas to increase the temperature of the material entering the adsorption tower, thereby preventing crystallization from blocking the system. 4. After evacuating and desorbing the other towers, gradually introduce air in increasing amounts to resume production. It is hoped that all operators involved in the decarburization process will observe carefully, summarize thoroughly, and apply their knowledge flexibly, in order to prevent various accidents such as water contamination from occurring at the decarburization station.