(Participation rewards available) Summary of handling emergencies in production operations.

Synthesis tower: 15 days ago. Location: The new 1.2-meter tower. At 9:30 p.m., all liquid level readings on the computer suddenly lost signal, including those for the ammonia separator, the second ammonia separator, the waste boiler, the intermediate liquid ammonia tank, and the ammonia cooler. Action plan: 1. Contact the instrumentation team to investigate the cause on-site. 2. Change all automatic settings on the computer to manual mode, especially those related to the waste boiler. 3. Go to the site immediately using walkie-talkies to check the liquid levels in the waste boiler and the intermediate liquid ammonia tank. 4. Turn on the electric heater to maintain a higher temperature in the tower. 5. Open the bypasses of the ammonia separator and the second ammonia separator slightly, and monitor the pressure gauge to allow some gas to escape, thereby preventing liquid ammonia from entering the synthesis tower

A fire broke out due to a leak in the cylinder below the one-meter ammonia synthesis tower. Time: 10 years ago (That’s a bit too early, haha!) ) Fluctuations in the system load caused fluctuations in the temperature of the gas exiting the tower, resulting in a fire due to leakage from the cylinder below the tower. Remedial actions: Emergency load reduction was carried out in the preceding processes; the pressure in the one-meter ammonia synthesis tower was reduced by releasing pressure, and once the system pressure in this tower dropped below 15 MPa, the leakage decreased. Open flames were extinguished using dry powder fire extinguishers, after which the cylinder beneath the tower was thermally tightened while under pressure to eliminate the leak. Later, when there was an opportunity for system maintenance, the gasket at the bottom of the one-meter ammonia synthesis tower was replaced. In the event of an emergency, the first thing to do is not to panic, provided that the safety of oneself and others is ensured ； Determine the cause of the accident and its level of danger, and then take effective measures to address it. In short, dealing with emergencies requires being both bold and careful. This post was last edited by snowdfr on 2009-2-9 14:49.]

Purification workshop: The conversion system was used to heat and reduce the catalyst, while the operators added carbon disulfide from barrels into the storage tank. The pipeline used for this purpose was homemade – it was pressurized with nitrogen and used to deliver the substance to the tank, with a flexible hose at the end of the pipeline. When carbon disulfide was being added from the fourth barrel, a fire broke out suddenly; the storage tank was surrounded by flames. There were several barrels of carbon disulfide present at the scene, and the situation was urgent. The personnel on site quickly used dry powder fire extinguishers and steam to put out the fire； One side notified the dispatch team to send reinforcements, and once the personnel arrived, the fire was quickly extinguished. Reason: Upon on-site inspection, there was no open flame in the area where the accident occurred, and the temperature of the surrounding equipment was not high enough to ignite carbon disulfide (the outlet pipe of the other converter’s low-temperature reactor was insulated and showed no signs of ignition; the temperature of the hot water pump’s outlet pipe was 75°C, while the auto-ignition temperature of carbon disulfide is 130°C). It is inferred that the source of the fire was the flexible hose connected to the pipeline; once this hose burned out rapidly, the pressure inside the tank caused carbon disulfide to spill out, leading to an intensification of the fire. However, since there was water inside the carbon disulfide storage tank, this prevented the carbon disulfide from vaporizing, thus preventing the storage tank from catching fire. According to the analysis, coiled hoses are non-conductive; when used to transport flammable liquids with a low flash point such as carbon disulfide, static electricity accumulates, leading to fires, which was the direct cause of this accident. Remedial measures: 1. It is prohibited to use plastic pipes for transporting flammable substances (liquids or gases). 2. Large quantities of bottled carbon disulfide must not be stored around the storage tanks. 3. Carbon disulfide storage facilities must not be in contact with or near high-temperature installations; in special cases, enhanced supervision and safety measures must be implemented

In 2005, after the major renovation, the system was put into operation. A massive fire broke out suddenly while the methanation furnace was being heated, due to gas leakage from the upper flange. Due to the high pressure of 24 MPa, the fire was extremely intense; it took an hour to put it out, and the upper platform was warped by the heat. It could only be dealt with slowly, by gradually reducing pressure to control the fire; people were organized to use high-pressure steam to put out the fire, and it was finally extinguished, resulting in another day of production disruption. It seems that safety in production should always be given top priority; just because a few screws weren’t tightened properly, such a serious accident occurred.

In 2007, as well, operations were resumed after the major repair; after air was supplied to the sixth stage, a leak at the flange of the blind plate at the outlet manifold of the compressor’s sixth stage suddenly caused a massive fire. Efforts were made urgently to shut down the system by cutting off the gas supply and releasing pressure, but due to the high pressure and intense fire, the pipes in other sections on the first floor of the compressor facility became heated and deformed, resulting in leaks. The fire was extinguished only after the system pressure had been released. The reason is actually quite simple: the flanges were not tightened properly, and the leak and pressure testing were not carried out in strict accordance with the requirements, which led to the accident. It is clear that there are no trivial matters when it comes to safe production; procedures must be followed strictly, one should not be afraid of hassle, and production cannot be organized on a whim.

103-B High-Pressure Steam Coiler Dry-Firing Accident: Cause Analysis and Handling I: Unit Status At 23:00 on the evening of February 20, 2009, the furnace went out due to a coal supply interruption in Boiler No. 4. In accordance with the relevant operation plan, Unit 2 for ammonia synthesis had its capacity reduced to 75%, and units 103-J and 105-J were shut down manually. On February 21, 130-J resumed operation to supply S100 from external sources. This results in high pressure in 101-F; meanwhile, due to the low load on the unit, the temperature of the process gas at the outlet of 103-B is 600°C, and the steam pressure in small vessel 122-F is 8.78 Mpa. Due to the large pressure difference between the two drum vessels, steam in 122-F was trapped and could not flow freely, which led to dry burning of the high-pressure steam coil in 103-B. II: Accident phenomenon FI-04104: 0 ； TI-04130: 176℃; TI-04121b: 684℃; PI-90: 10.14 Mpa; PRCA-04124: 8.57 Mpa. III: Accident handling procedures: 1. Immediately inform the relevant department staff and production supervisors. 2. Contact the instrumentation team promptly to verify whether the instrument readings are accurate. 3. Lower the liquid level in vessel 122-F right away to prevent steam from carrying water. 4. Increase the pressure in vessel 122-F. 5. Reduce the pressure in vessel 101-F and open PCV-13 wider. These measures did not yield significant results. Key step: Slightly open HCV-04106 for venting. After that, it was observed that TI-04130 increased rapidly; at the same time, FI-4104 showed a flow rate, which increased over time, and PRCA-04124 also started to rise. The temperature of TI-04121b dropped back to normal levels. IV: Cause of the accident: Due to a mismatch in the pressures between the two vessels, a large pressure difference occurred, which prevented gas generation in the smaller vessel. As a result, no fluid flowed through the coils, and heat could not be dissipated. This led to an increase in the temperature of the flue gas at TI-04121b. Since there was no fluid at the outlet of the coils for TI-04130, its temperature dropped as low as 136℃. Note: Due to the high temperature of the flue gas and heat accumulation, increasing the venting rate will cause steam to carry away a large amount of heat in a short time, resulting in a rapid rise in the temperature of TI-04130. Given the high temperature and pressure of the medium, care must be taken when opening the vent; it should not be opened too widely to prevent the temperature of TI-04130 from rising too quickly and damaging the coils. When it is observed that the temperature is rising rapidly, the vent valve must be closed promptly to reduce the amount of gas released, thereby allowing heat to be removed gradually and slowly.

Case of synthesis unit: 1. Overpressure explosion of the buffer tank in the Ф1600 synthesis vent main pipe. Cause: Due to low air pressure, the gap shunt valve closed automatically, resulting in significant fluctuations in the temperature of the catalyst layer; this led to poor ammonia synthesis reactions and an increase in system pressure, causing leakage at the lower part of the synthesis tower. When the system is depressurized, improper operation occurs: the make-up gas vent valve is opened first, followed by the atmospheric vent valve. At the same time, the atmospheric venting was too aggressive, leading to gas accumulation and overpressure, which caused the vent buffer tank to explode due to overpressure. Prevention: When releasing pressure from the system, the atmospheric vent valve should be opened first, followed by the vent valve at the back of the tower, as well as the vent valve at the front of the tower or the make-up air vent valve. Strengthen safety education, follow operating procedures strictly, and prevent equipment from exceeding pressure limits. 2. Reasons for the excessive starting current of the Ф1600 Synthesis 2# Circulator: Date: January 18, 2005; Shift: Third shift; Location: 1600 Synthesis 2# Circulator. What happened: On January 18, during the third shift’s shift change, production continued on Unit 27, with Circulators 1# and 3# in operation. At 8:30, it was discovered that a set screw on the valve on the west side of Circulator 3# was loose; the machine was to be shut down to address this issue. At 8:40, the 2# circulation pump was started up for idling following the normal operating procedure; the motor, oil pressure, and noise levels were all found to be normal. At 8:50, pressurization was started at the inlet. But as soon as the pressure reached 20 MPa, it was found that the current in the circulator motor had risen to 80 A (the normal full-load current is 40 A with a limit of <60 A). The inlet valve was immediately closed, and venting for pressure release was initiated. After the pressure was released and the machine ran idly, no abnormalities were observed; it was suspected that during a quick inspection, all the bypass valves had been opened, but no issues were found. The machine was shut down at 9:00 to investigate the cause. Cause analysis: Based on my own judgment, I suspect that there is a problem with the bypass valve. Since there were no abnormalities in the noise produced by the equipment, the motor current, or oil pressure during idling, it is likely that there are no issues with the equipment or the motor; therefore, the only possible causes are related to the bypass system. If the valve is opened too slightly or if its core comes loose, it can lead to the aforementioned problems. At that time, I checked the bypass valve and found that it wasn’t closed – it was fully open. Therefore, it is suspected that the short-circuit valve heads have not been fully opened. The blacksmith was instructed to remove the bypass for inspection. Upon examination, it was found that only one steel ball remained at the connection between the valve head and the valve stem; this resulted in an excessive gap between them. Although the valve stem was fully opened, the distance between the valve head and the seat was small, allowing gas to circulate through the bypass even when the system was not in use. However, an increase in the volume of gas under pressure leads to an increased pressure difference between the inlet and outlet, resulting in overcurrent; this is the main cause of overcurrent. Solution: Replaced the bypass valve of the circulation pump; operation resumed normally, and the problem was resolved