Synthetic Ammonia Process Technology Exchange Area [Daily Question 2009-02-28]

1. Contact the compression section and simultaneously stop supplying desulfurization liquid to the system. 2. Close the outlet valve of the lean liquid pump, shut down the pump and close its outlet valve; also close the liquid discharge valve depending on the liquid level. 3. Stop the cleaning pump, and close the water supply valve and drain valve on the cleaning tower. I’m not sure if this is appropriate – please offer your feedback, OP

The answer on the 2nd floor seems off-topic; it still merely encourages new members to share their opinions.

Procedures for starting and stopping the main equipment of the position. Normal startup steps: a: Procedure for starting the multi-pole pump: Starting procedure: ① First, rotate the pump by hand to check whether its operation and noise are normal (pay special attention to the connection between the worm gear turbine and the motor to ensure it is functioning properly: when the motor is rotated in one direction, the turbine should not rotate; conversely, when the turbine is rotated, the motor should not rotate)； ②Activate the turbine’s cooling water circulation system and check whether water is flowing ； ③Contact electricians, fitters, and instrument technicians to go to the site to check for any abnormalities ； ④After no abnormalities are detected, open the pump inlet valve; simultaneously check whether the desulfurization pump and the turbine mechanical seal are leaking ； ⑤Contact the relevant power distribution room to restore power once there are no abnormalities ； ⑥The barring gear is functioning properly; after electricians, fitters, and instrument technicians inspected the site and found no abnormalities, the pump was started ； ⑦The outlet pressure of the desulfurization pump is controlled to be between 3.1 and 3.4 MPa. The current level is monitored to ensure it remains at ≤30 A. Meanwhile, the inlet pressure of the turbine is controlled via a bypass system, with this pressure kept at 19–20 kg. (In actual production, the inlet pressure of turbine No. 2 is about 0.5–1 kg lower than that of turbine No. 3; in practice, we generally use the inlet pressure of turbine No. 2 as the reference.) ； ⑧Once production returns to normal, maintain the outlet pressure of the desulfurization pump between 3.1 and 3.2 MPa, while keeping all other parameters unchanged. b. Turbine startup procedure: ① First, start the desulfurization pump; once it is operating properly, monitor the pressure at the turbine inlet. Then open the turbine outlet valve, and open the turbine inlet valve when the pressure at the inlet is between 19–20 kg ； ②Adjust the outlet branch valve from the desulfurization tower to the flash tank based on the turbine inlet pressure. When the turbine inlet pressure is below 19 kg, reduce the flow through the turbine branch line; when doing so, pay attention to the liquid level in the desulfurization tower to prevent it from rising too high, which could cause fluctuations in production. When the turbine inlet pressure is high, increase the flow through the turbine branch line slowly, and be careful of the current drawn by the desulfurization pump to avoid overcurrent that could lead to shutdown ； ③The liquid levels in each tank have been adjusted to normal levels ； Normal shutdown procedure: First, close the outlet valve of the desulfurization pump and cut off the power supply ； Next, close the inlet valve of the turbine and the outlet valve of the turbine, and adjust the liquid level in each tank ； Precautions for starting and stopping turbines: ① When starting, first open the outlet valves of (all) the turbines, then open the inlet valves of (all) the turbines; two people can carry out these operations simultaneously ； ②When shutting down, first close the turbine’s inlet valve, then close the turbine’s outlet valve; the two operations can be carried out simultaneously by two people ； Shutdown procedure: Follow the startup and shutdown steps by first turning on the backup equipment and then shutting down the equipment that is currently in operation. Emergency shutdown steps: ① Turbine: Close the turbine inlet valve, close the desulfurization pump outlet valve, and cut off power immediately. VIII. Startup and shutdown procedures – Step 2: Original startup operation guidelines ① First, open the injector valves (7–8) ； ②Apply pressure to the system; when the system pressure is ≥ 0.8 Mpa, open the pump inlet valve and start the pump. Once the pressure is normal, open the pump outlet valve ； ③When there is a liquid level in the desulfurization tower, open the valve from the desulfurization tower to the flash tank ； ④When there is a liquid level in the flash tank, open the valve from the flash tank to the regeneration tank ； ⑤Once the system liquid level and pressure are both normal, start the turbine and adjust the liquid levels in each tank to normal levels. Operating procedures for shutdown of the two-stage stripper: ① Before shutting down, the turbine should be stopped first ； ②Upon receiving the stop signal, close the pump outlet valve and cut off the power ； ③Quickly close the liquid outlet valve of the desulfurization tower and the outlet valve of the flash tank ； ④Close the inlet and outlet valve circuits of the desulfurization tower, close the valves of each injector, and shut down the system while maintaining pressure. Driving steps ① Top up the desulfurization fluid to the operating liquid level of each device ； ②The desulfurization system is purged with qualified inert gas; the vent valves of various devices are opened in sequence according to the process, and the gases are discharged until sampling at the system outlet shows that O2 ≤ 0.5% and CO + H2 ≤ 5%, meeting the requirements ； ③While sending the transformed gas, start the lean liquid pump to circulate the solution, and adjust the load of each pump as needed ； ④Analyze the H2S levels at the inlet and outlet of the system to ensure effective desulfurization ； Precautions: ① Be careful when taking samples by displacement; stand in the upwind direction ； ②Strictly enforce process specifications ； ③Maintain communication with the relevant departments while driving ； ④The solution circulation rate is uniform, preventing large fluctuations. Normal startup plan for the second stage of operation: ① Add new solution according to the volume of the solution and its composition, in order to ensure a rapid transition to full-scale production; this also helps meet the requirements related to increasing the H2S content in the inlet gas ； ②Once the system-wide inert gas displacement begins, contact the converter to start sending gas backward in order to initiate the inert gas displacement ； ③As per the instructions from the head office, ensure that there are no dead corners at all at each venting, discharge, analysis sampling point, and instrument pipeline in this area ； ④Once the inert gas in the two-stage dehydration system meets the requirements, it is used in conjunction with the shift process for heating and vulcanization. ⑤Before starting the heating sulfuration process in the converter, open the inlet valve for the secondary desorption unit. Check the drain valve at the outlet separator of the converter’s inspection system, and contact the dispatch team to add water to the desulfurization tower; once it is full, stop adding water. Drain some of the water through the bottom drain valve of the tower (be careful to prevent a negative pressure from forming inside the tower during drainage), and wait for the tower to be flushed ； ⑥The gas generation after transformation is satisfactory; when the pressure before the inlet valve of the second desulfurization unit is ≥0.4 MPa, the inlet valve of the second desulfurization unit is opened along with the drainage valve of the desulfurization tower to remove water accumulated inside the tower. During drainage, 7–8 injectors are activated, and once all the water has been removed, the desulfurization pump is started. Once a liquid level appears in the desulfurization tower, its outlet valve as well as the outlet valve of the flash tank are opened, ensuring that the H2S concentration at the outlet of the gas delivery control system in the subsequent process stage is ≤8 mg/Nm3.

Replacement plan for the ethylene exchange transformation system I. Replacement 1. After shutting down the transformation system and releasing pressure, a fitter inserts a metal blind flange at the oil inlet flange (Pg16 Dg200) – a support frame is installed first. 2. The fitter pried open the plug plate at the inlet flange of the gas-water separator (Pg16 Dg250); this plug plate separates from the flange on the south side, facilitating exhaust replacement (a frame is set up first). 3. The fitter inserted a blind flange at the rear flange of the drain valve of the gas-water separator (Pg16 Dg50). 4. The operator closes the inlet and outlet valves of the low-voltage transformer, as well as the hot feed line valve, and opens the bypass valve of the low-voltage transformer. 5. Close the water supply valves for Condenser No. 1 and No. 3. 6. Open the steam valve for the conversion system, as well as the steam valve on the waste discharge pipe of the conversion furnace. Also, open the vent valve, drain valve, and oil discharge valve of the conversion system. 7. After the system replacement is completed successfully, close all vent valves and drain valves. 8. Fill the catalyst with nitrogen through the sampling valve of the third section of the conversion furnace (J41W-16 Dg15) (six bottles of high-purity nitrogen should be prepared in advance). II. Welding pipe blind flanges 1. Set up supports in advance at the inlet and outlet pipes of the medium-frequency furnace (φ325×8). 2. Once the replacement analysis is satisfactory and nitrogen protection is in place, cut the steam supply pipe at the sewage discharge pipe of the medium-frequency furnace, and weld a 10mm thick steel plate over the pipe opening to seal it completely. 3. Cut the inlet pipe of the medium-transformer furnace and weld it shut using (machinically prepared φ350 σ=3) steel plates. 4. Cut the outlet pipe of the medium-transformer furnace and weld it shut using (machinically prepared φ350 σ=3) steel plates. 5. It is absolutely not allowed to cut both the inlet and outlet of the medium-temperature furnace at the same time, as this will cause air convection and oxidize the catalyst. III. Timeline 1. Depressurization of the conversion system (8:00–8:30 on March 10) 2. Fitters entering the site to install blind flanges (8:30–9:30 on March 10) 3. Steam displacement (9:30–10:30 on March 10) 4. Mechanical repair team arrives at the site at 10:30 on March 10. 5. The B intersection and A intersection scaffolding must be completed by March 10. Any matters not covered shall be resolved **on-site. Ammonia synthesis process 2009-3-1