Recently, heavy snowfall has occurred across the country and temperatures have dropped to their lowest levels. Which areas are likely to be affected by freezing conditions?
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Recently, heavy snowfall has occurred across the country and temperatures have dropped to their lowest levels. Which areas are likely to be affected by freezing conditions? In our facility, the alkali preparation tanks used for methanol distillation, the main steam valves and pressure guide pipes, as well as the remote level monitoring systems for the methanol tanks have all experienced freezing issues. Accidents can easily occur if proper precautions are not taken during operation; therefore, we hope that everyone will share their experiences and lessons learned! This post was last edited by zhangchaosen on 2008-1-27 20:24]
In fertilizer and chemical production, the parts that are prone to freezing include standby equipment such as backup pumps; when these devices are not in use, the actual equipment itself can easily crack due to freezing； Steam, blind ends of water pipelines, valves, etc ； The level gauges of tower equipment are prone to cracking or showing false levels ； The instrument air terminal or the “U” shape is prone to being blocked by ice ； . . . . . . .
Coke oven gas transmission pipelines for the methanol or ammonia synthesis process, as well as the process pipelines in the chemical product recovery section
When the drainage pipeline has poor drainage or is not in use for a short period of time, it can easily freeze due to its thin diameter； During short-term parking in winter, many drain lines freeze ； The spray water from the circulating water tower tends to freeze easily, and various drainage ditches can get frozen when discharging water intermittently ； The discharge pipes at the bottom of some separators are prone to freezing when proper insulation measures are not in place or electric heating is not used ； After steam is discharged, condensate water remains, and if it isn’t removed properly, it can easily freeze, and so on... In short, preventing freezing and maintaining proper insulation are very important in winter, as it can affect the entire production process.
The areas most prone to freezing are the water systems, as well as those dead ends where freezing is likely to occur. It is necessary to regularly check the steam traps and verify whether the heating systems are functioning properly to prevent freezing. I’m not sure if the person asking this question lives in the north; if so, frost prevention is the most important measure for production during winter.
Don’t forget the outdoor stairs, corridors, instrument pressure pipelines, and so on.
I just got off work; it’s another heavy snow day today. I need to send over the problems that arose today as soon as possible. Today, accidents occurred in both the methanol and distillation units, where the instrument air supply to the valves froze, causing the valves to open automatically. Fortunately, it was detected early so no accident occurred, but it still caused the temperature in the methane tower to drop to 280 degrees, haha. However, I have seen this situation of instrument air freezing quite rarely, which indicates that the water content in our instrument air is high. As for the specific approach, those in the compression workshop need to figure it out. However, what the friends upstairs said is quite typical.
Parts prone to freezing in urea production: the pipes from the urine tank to the flash feed, the outlet pipe of the desorption tower, and the hydrolysis gas phase pipe. . . . . . . . . . . . . . . .
It’s really cold when it snows; our drainage system keeps leaking when it’s cold, and there are also pumps that haven’t been turned on yet
The instrument air should be dried; with a dew point below –40 degrees (in the south), it will not freeze. This used to happen frequently in our plant, but the problem was resolved after the modifications were made. In the past, to prevent freezing, we would slightly open the drain valves on the compressed air buffer tank before it entered the workshop as well as those on the filters feeding into the system; this was just enough to get through the winter, haha. . . :lol
Some magnetic flap level gauges with jackets, such as those used in desulfurization and decarburization solutions, may experience gradual evaporation and crystallization of the liquid inside them due to long-term heating with steam, which can lead to blockages in the level gauge; in such cases, hot water can be used for heating.
Areas where fluid cannot be drained promptly are most prone to freezing; it is at such times that the flaws in the design become apparent, necessitating timely technical improvements
Personally, I don’t think freezing will be an issue, unless it’s a new factory; our factory has been in operation for decades. We take excellent measures to prevent freezing – we conduct pre-inspections before each shift, and in winter we pay special attention to preventing freezing, ensuring a steady flow of water. Additionally, there is steam available to address any issues that may arise due to freezing, so the situations mentioned on the first floor hardly ever occur.
A simpler approach is to drain the accumulated fluid in a timely manner to ensure that the medium remains in flow.
In ammonia synthesis, the compressed oil drain valves tend to freeze; in previous years it was necessary to check them every half hour, and this year the situation is likely even worse. Recently, there has also been a shortage of steam, making it difficult to blow air through them.
The cold snap has not yet passed, and there have been many similar incidents in these days. Although measures have been taken to address them, often by adding steam tracing pipes, the problem now is that excessive condensate is being discharged, resulting in a shortage of demineralized water and a tight supply of steam; sometimes it is necessary to reduce production volume. It seems that this problem hasn’t been resolved very well; I hope that the managers will pay attention to it during the major repairs.
Power rationing has also started now; after the equipment in use is shut down, it is necessary to take precautions against freezing, especially for equipment such as compressors that have jacketed cooling water systems. Also, pay attention to the pump casing
I don’t yet have any real hands-on experience, but by reading everyone’s experiences, I’ve learned a great deal. I feel that in the future, when I design something, I will definitely need to think things through carefully
First, identify the freezing point and place signs indicating it; establish anti-freezing measures, and then, when the temperature approaches 0°C, check that these anti-freezing measures have been implemented. Everyone who has spoken about the freezing point has made good points; I’d like to remind everyone, especially those in areas exposed to drafts.
Another wave of cold weather has arrived; it’s indeed quite cold this year. I hope everyone can get through the winter safely and steadily! A few days ago, the problem of instrument air freezing continued, and there was no good solution; the only option was to monitor closely and identify issues through the data. Problems often occur when the valve opening is small, or with media such as steam, water, or those with a high freezing point.
Of course, while the cold snap causes problems for our production processes, it also reduces the load on the circulating cooling water, allowing for fewer hours of fan operation and thus lower energy consumption. It provides certain favorable conditions for our current power rationing efforts.