Problems with the magnetic flap level gauge in Kellogg modular ammonia coolers
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I have encountered situations in several Kellogg ammonia plants where the magnetic flap level gauges used with their modular ammonia coolers (120-CF) had a very high failure rate. The specific parameters are as follows: Liquid ammonia temperature /°C, Pressure/KPa (gauge pressure): 120-CF4: 30 500; 120-CF3: 0 350; 120-CF2: -10 100; 120-CF1: -33 15. The actual problem is that aside from the level gauge on the fourth stage, those on the other three stages were all damaged, resulting in an inability to detect the liquid level on site. Could everyone discuss what the reasons are? Is it because the length of the section hanging outside the level gauge causes the liquid ammonia to vaporize rapidly once it enters the magnetic flap level gauge? Is it the intense vaporization phenomenon that causes the magnetic flap level gauge to freeze after heat absorption due to throttling? ? Are there any other better level gauges? ? ?
I’m not familiar with level gauges, but I have used them before; I’ll share some thoughts. It seems that the level gauge used by the poster doesn’t perform well in low-temperature conditions. Is it a frost-proof level gauge? I have used frost-proof level gauges before, but the float moved up and down quite a lot, making them not very useful. Of course, the ones I used were domestic products, which were cheaper. Recently, I’m thinking of switching to more expensive ones
It’s a very ordinary level gauge, with no anti-frost measures. Generally, this level gauge is also of domestic manufacture.
However, compared to level gauges for ammonia, the operating conditions for ammonia are more stringent; the temperature of the process medium is around -26 degrees, and the pressure is that of a synthesis cycle, at 12 Mpa, yet no such problems have occurred. Is there a better level gauge available?
I don’t understand things like the parameters of the gas components in ammonia; I’m just speculating. Could it be that the degree of liquid subcooling is high? Although the temperature is low, the liquid inside the liquid equilibrium tube does not vaporize immediately after absorbing heat. Does this make the level gauge operate more stably and reliably? In a nutshell, it’s difficult for liquids to vaporize
We use glass plate level gauges; the repair rate is low, but it’s difficult to see the actual liquid level clearly. Each time the liquid level is observed, it must be identified carefully.
There’s some fluctuation or something, which is fine; but here we can’t see it at all, or there isn’t any such thing to begin with.
Our on-site level gauge for the ammonia cooler does have scales, but they are not continuous – they are separated from each other – and it’s not clear whether it shows the actual liquid level; a magnetic flap level gauge is being used instead.
Reply to 8# huagong061107: Did you take a magnet to the site to brush the magnetic flip switch? Also, has the level gauge been drained on time?
Hehe, I’m not sure about that. I just started learning about ammonia synthesis; as soon as I arrived at the control room, I realized that the level gauges weren’t working properly.
Haven’t gone to the site to take a look? Wasn’t these level gauges drained before?