If both the local level gauge of the ammonia cooler and the DCS are completely damaged, can the actual liquid level be determined based on frost formation?
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If both the local level gauge of the ammonia cooler and the DCS are completely damaged, can the actual liquid level be determined based on whether frost has formed on the gauge?
No, if too much ammonia is added to the ammonia cooler, frost may not form even in the absence of a gas phase space. Therefore, once such a situation occurs, it’s best to stop the operation for maintenance purposes, as a safety measure. However, those with extensive operational experience can try to maintain production by adjusting the size of the control valves and monitoring the temperature, but this approach is quite risky
The ammonia cooler can be used based on the temperatures before and after; frost formation can serve as an auxiliary indicator for determining the liquid level!
This has also happened here; all three level gauges for the ammonia coolers were damaged. However, in order to start up the system as quickly as possible, they were not repaired. Instead, judgment was made based on the temperature difference before and after the ammonia coolers. Under normal circumstances, with a temperature difference of 7 degrees, it is sufficient to maintain this difference by gradually reducing the valve position for ammonia supply, thereby ensuring that no liquid ammonia reaches the ammonia compressor
I have this situation here; it can run. Also, make sure the temperature of gaseous ammonia isn’t too low
When no other methods are available, checking the freezing condition of the level gauge float can serve as a reference. The main problem is that ice will form even if the liquid level was once higher than the upper limit indicated by the level gauge; moreover, the ice on the outside of the float does not melt even when the liquid level drops. So if you rely on this, you must keep the liquid level low at all times.
The risk is relatively high; it is recommended to handle it as soon as possible.