Ammonia synthesis accidents and handling solutions since this year

On March 23, the flange on the outlet pipeline of Yuntianhua’s synthesis tower broke down due to incorrect material selection in the design by the Eighth Research Institute for Chemical Engineering, resulting in a shutdown of the plant that lasted nearly a month.

I work at an investment company, working on ammonia synthesis projects. There is something called project risk, and I really want to learn more about this area as well!

Our company has had no major accidents, but there have been quite a few minor ones: 1. During refining operations involving welding, a large fire broke out due to leaks at the flanges caused by high oil content, making it impossible to extinguish the fire and forcing a shutdown of the plant. 2. Air leakage occurred at the filler of the compressor’s inlet valve; the welder failed to turn off the power supply of the welding torch, which caused a fire. Remedial action: Shut down the machine and seal the inlet.

On August 15, due to the failure to drain the condensate from the steam pipeline in a timely manner, the pipeline vibrated and experienced liquid slugging, which caused the gasket of the steam valve to be punctured instantly, injuring the operator who was preparing to start the drain operation.

Oil leakage from the oil pipe connection of the gas generation cut-off valve spilled onto the dust collector, caught fire due to the high temperature, and caused the gas generation process to stop.

An accident occurred in the compressor plant when a grating panel fell, fortunately the employee was unharmed. All the grating plates have been reinforced anew! ! !

Please talk about process or equipment accidents and their handling methods. A collapsed house doesn’t count:victory:

This post was last edited by GreenFieldWalk on 2009-9-6 at 14:43. Around 4 o’clock yesterday, during the midnight shift, the liquid level in the NHD decarburization absorption tower fluctuated rapidly, frequently, and significantly (between 0% and 100%). The operator on duty thought it was due to liquid accumulation; after observing for over ten minutes, reducing the flow rate did not improve the situation, which instead worsened. At 4:10, the operator called the shift supervisor to go to the site and check the operation of various valves. I made it clear to him that this phenomenon was not caused by liquid accumulation, and that if it really were due to liquid accumulation, it would indicate serious problems with the internal components of the tower. One reason for the lack of a thorough inspection was darkness (they had flashlights), and the other reason was their reluctance to conduct a proper inspection, so no issues were detected. At 5:00, as the liquid level fluctuations intensified, the carbon dioxide pressure dropped close to zero. Fearing that process gas might enter the carbon dioxide pipeline and cause an explosion of urea, I ordered an emergency shutdown of both urea production units. At this time, due to fluctuations in the liquid level, the liquid level in the decarburization regeneration tower dropped to zero, causing the decarburization pump to become momentarily vacuumed. Immediate preparations were made to switch over to methanation mode; orders were already sent to the synthesis workshop. Thanks to timely exhaust from the site, the solution circulation rate was restored, and the switch to another gas processing mode was not necessary. At 5:30, when the deputy director in charge of gas production arrived at the site and ordered the operators to check the valves there once again, it was found that the feedback linkage of the valve actuator for the liquid discharge valve LIC4001 in the decarburization tower had come loose. The instrument technician resolved the issue within a few minutes, and production resumed normal operations. However, it was not until around 3 p.m. that the two urea production systems returned to normal operation. The sequence of events doesn’t seem complicated, but there is one thing: if urea is produced normally and process gas enters the carbon dioxide pipeline, the consequences could be disastrous. Another issue is that the operators are too stubborn, ignoring proper suggestions; they are overconfident and prone to extreme behavior. When there are abnormalities in the manufacturing process, all possible factors must be taken into consideration before making any decisions. As long as there is even a hint of something correct, it is necessary to carefully investigate the reasons behind it. It’s a profound lesson.

Hehe! I guess Green Grass Walk is in charge of scheduling – they’ve posted more posts for us; generally, people in such scheduling roles have quite extensive experience! It seems like the problems upstairs are all minor issues; as for my factory, there have been several serious problems. After maintaining a electrostatic precipitator, the operator used steam to purge it and then asked an analyst to conduct a test. Unluckily, this analyst was inexperienced – he just made some random adjustments and declared everything to be fine. When air was introduced to start the equipment, an explosion occurred, destroying the water seal pipes. Thankfully, no one was injured, but it really scared us to death. The security guards on duty heard the explosion and immediately ran away as fast as they could! The speed is so fast; I bet even Liu Xiang would shake his head at that! Another time, gas got into the air intake pipe, which resulted in a large section of the air supply pipe bursting – lucky we were! No matter how I look at it, it wasn’t injured!

Accident involving the casing of Desulfurization #3 Roots blower: On September 4, 2009, the plant was shut down to address some issues before resuming operation. For desulfurization purposes, #2 Roots blower was started first; at 16:50, #3 Roots blower was brought online as well. After checking it, it failed to start due to a power supply problem. Operator Zhu called electrician Ma to investigate and fix the power issue. At 17:20, the blower started up successfully and began operating, with an operating current of 320A (the rated current being 560A). By 20:30, Operator Zhu heard abnormal noises coming from the Roots blower and noticed a drop in the system’s outlet pressure; he concluded that the blower had tripped. He immediately ordered assistant operator Wang to reduce the system’s operational capacity, while he rushed to the Roots blower room and found that it was indeed #3 Roots blower that had tripped. He quickly opened the bypass valve for that blower, while Wang went to close its outlet valve. At that moment, on-duty dispatcher Yang arrived. The outlet valve of the Roots blower was only half closed. Despite the fact that the blower was still running in reverse, Dispatcher Yang violated the operating procedures by pressing the start button for that blower. As a result, the blower started rotating rapidly, producing loud noises, and air began leaking from the seals at both ends. Zhu quickly stopped the blower and closed the valves. Upon inspection, it was found that the fan blades, fuselage, and rear wheels of the machine were broken, the main shaft was deformed, and the entire machine was beyond repair. Cause of the accident: 1. The machine had experienced several intermittent tripping incidents before, and the electricians were unable to identify the cause; it was later determined that the issue was caused by a fault in the intermediate relay. Therefore, the electrician was unable to determine the cause of the rotor pump tripping, and this inability to identify the cause led to multiple trips of the rotor pump, which in turn became the origin of the accident. 2. The main cause of the accident was that the on-duty dispatcher violated the operating procedures by starting the equipment, which was still in reverse rotation.