Abnormalities occurring in ammonia and refrigeration machine production and corresponding handling measures
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Experts, please share what kinds of abnormalities you have encountered in production and the measures you took to address them Knowledge already covered in the book, such as excessive or insufficient temperature, excessive or insufficient pressure, and excessive or insufficient liquid level, will not be discussed here.
I’ll throw out some ideas first to get things started! 1. Material of ammonia water pipelines in the ammonia absorption tower: The designed material for these pipelines is carbon steel; however, ammonia water is highly corrosive, which may lead to corrosion and leakage in the pipelines. Action taken: The wall thickness of each fitting is measured every six months, with records kept ； Replace it when necessary. 2. Frequent fluctuations in the speed of the turbine used in ice makers. Phenomenon: The electro-hydraulic converter used for the turbine has been repaired multiple times, yet this issue persists; the speed fluctuations range from 100 to 500 revolutions per minute, which has a significant impact on the manufacturing process. Remedial action: Purchase a new electro-hydraulic converter in advance as a spare ； To be replaced during a major maintenance shutdown. 3. The oil heating unit lacks a level gauge. Phenomenon: There is no level gauge or sight glass on the oil heating unit, making it impossible to determine the liquid level visually. If the liquid level is too high, it will cause the liquid to be carried into the flare line. Remedial action: Install on-site level gauges or sight glasses during the major repair. 4. The fire sprinkling system for liquid ammonia spheres is under manual control. Problem: In the event of an emergency, it is not possible for operators to be on site to open the valves, which poses a serious safety risk. Remedial measure: Add a control valve after the manual valve, keeping the manual valve in the fully open position.
Haha, your chiller isn’t even considered abnormal – according to you, the turbine suffered from liquid slugging. You should be glad that your machines were able to withstand it.
Reply to 3# julius6054: Since you’re here, please upvote my post. Share any interesting abnormal phenomena that occur in your factory~
So far, there has been no phenomenon of liquid hammer in the turbine, but there have been quite a few unusual situations. When the warm-up startup does not succeed, it’s because there isn’t enough time; people then rush to continue with the startup, which causes localized thermal bending of the rotor. Over the following year, the vibration in the turbine becomes more noticeable: the periodicity isn’t very strong, but the vibration levels keep fluctuating. At first, when they reached 70 or 80 micrometers, it wasn’t considered a problem, but things got worse as the values rose to 100 micrometers. Eventually, the situation became even more severe, leading to interlocks being activated, but there was nothing that could be done about it. It’s similar to your situation – you can’t just stop operating the turbine; you have to keep it running. But after replacing the rotor, the vibrations stopped fluctuating; however, the problem of speed fluctuations remained. The electro-hydraulic converter was also replaced, but it still didn’t work. It seems there were quite a few things that went wrong this year.
I’ve seen it happen twice: once the cold discharge tubes of the chiller broke, and another time the gasket in the compression cylinder came unseated. Since our plant uses a sulfur-free ammonia solution in its processes, all that’s needed is to wear the appropriate gas mask, shut down the chiller, and then redirect the gaseous ammonia coming from the synthetic or copper-washing ammonia coolers to be used as sulfur-free ammonia solution – this won’t have a significant impact on production； All that’s left is maintenance.
Please also write down how to deal with excessive or insufficient temperature, excessive or insufficient pressure, and excessive or insufficient liquid level. Thank you.
Reply to 6# Edong Lone Wolf: Could you explain in detail how your pipes broke, and how the gaskets were blown away?
...Could you send me an electronic version of 《Questions and Answers on the Production Operations of Small and Medium-sized Ammonia Synthesis Plants》? Haha, thanks. 1157729245@qq.com
Reply to 9# 90423042: There are many options to search for in Haichuan! Version 2: http://bbs.hcbbs.com/viewthread.php?tid=811829 Version 3: http://bbs.hcbbs.com/viewthread.php?tid=613344
Reply to 8# chenziang12: It is mainly caused by overpressure in the ice machine, as there is no water in the cold air exhaust of the ice machine