【Weekly Topic】Discuss the equipment quality issues in our unit and some of the consequences they have caused (2011.06.13-06.19)
Thread Content
This post was last edited by netcraft on 2011-6-14 08:20. It discusses the quality issues with equipment in our organization, as well as the consequences and solutions related to these issues. This includes stories about high-quality equipment, low-quality equipment, and various amusing or interesting incidents that occur during equipment maintenance. 1. There is no need to hide posts; discussions can take place freely ； 2. For ordinary responses (i.e., meaningful analyses or discussions), a reward of 5 to 15 wealth units or an equivalent amount of charm is given; for in-depth analyses and forward-looking, accurate responses, a reward of 20 wealth units or an equivalent amount of charm is awarded.
The unit’s original static defouling equipment was built by purchasing electrical components on its own, which led to frequent malfunctions and the need for emergency repairs. As a result, during one such repair, the replacement was not thorough, resulting in a safety accident.
Loose wiring terminals of the high-voltage motor caused a shutdown of power supply throughout the plant. . . . . .
The adjustment of the air compressor in the nitrogen production unit caused a shutdown of the entire plant
A plate heater leaked, causing corrosive substances to enter the steam condensate. This condensate is used by all the boilers and in production processes throughout the plant, which led to the need to discharge and replace the entire amount of condensate in the plant, as well as to conduct inspections on the equipment.
The water tank of the Roots blower froze and cracked. The decommissioned (spare) Roots blower had all its water discharge ports opened to allow water to flow out, and the valves showed no internal leakage; yet it still cracked due to freezing last winter. After consulting units with experience in using this equipment, it was found that after draining water from the Roots blower, compressed air must be used to blow it out so that no water remains in the water tank, thereby preventing freezing.
The rotating gas blower had to be shut down due to its maintenance cycle, and another blower was prepared to take its place. Without checking whether oil was returning after starting the oil pump (in violation of operating procedures), the backup blower was started in a hurry. As a result, the oil pressure did not reach the required level, and the blower failed to start; meanwhile, the existing blower’s speed decreased, causing gas to fill the entire plant, compromising safety and affecting the production processes in the company’s later stages.
We have inspected all of our company’s heat exchange equipment for leaks, and we are now planning to replace them in batches. In the past, circulating water heat exchangers that used methanol or acid gas as the working medium mostly employed carbon steel tube bundles; now they are being replaced with stainless steel ones. Internal leaks currently have a serious impact on product quality and process parameters, so it’s important to remember that you get what you pay for – don’t seek cheap alternatives.
The impeller of the titanium fan is broken; it’s not clear what the cause is. The newly purchased titanium fan had been in use for just over ten days when it suddenly stopped working. After taking it apart for inspection, it was found that the impeller inside was cracked and damaged. The cause is unknown, but there is a suspicion that the material may be defective, as rust was observed on some of the welds earlier on. It could be a problem during equipment installation; the specific cause is under further investigation. Everyone can also help analyze it – thank you! The medium is wet chlorine in the chlorine main pipe, with a pressure of only a few KPA; it’s really puzzling!
The heads of several heat exchangers in the unit’s low-temperature methanol washing system have developed cracks on multiple occasions; analysis of the cause revealed that it was due to problems with the stainless steel heat treatment, forcing the replacement of those heads!
I have previously designed condensers and after-coolers that required to be placed one above the other; therefore, the liquid outlet of the condenser and the inlet of the after-cooler had to be on the same vertical line. This issue was taken into account during both the design and review phases. However, during the verification process, the relationship between these two heat exchangers wasn’t considered, and the vertical positioning of the pipe connections was changed, resulting in a blueprint with a 300-mm hole already made. When the equipment was manufactured, it turned out that the two condensers couldn’t align properly, so the hole had to be plugged up and reopened. In the end, the device looks very ugly. A lesson, ah