Methanol drum liquid level
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Our company produces 200,000 tons of monohydric alcohols per year; the steam generated by the drum is at a pressure of 25 kgf/cm2, corresponding to 0.9–1.1 tons of steam per ton of alcohol. Currently, we are facing the issue of either high drum pressure due to a high liquid level in the drum, or high drum pressure due to a low liquid level (all other operations are normal)
The drum pressure is controlled by the backpressure valve and is independent of the liquid level; however, it is important to keep the liquid level within the normal range, avoiding fluctuations that are too high or too low.
It has nothing to do with the liquid level? If the liquid level is high, the space for gas evaporation at the top becomes smaller – is there any impact?
Regardless of the liquid level, the drum pressure is controlled by a pressure control valve. Generally, the drum liquid level is kept at a high level to prevent the drum from drying out
In my opinion, the level of the drum liquid does have an impact on pressure; however, the purpose of controlling this liquid level is to maintain pressure stability, which in turn facilitates the regulation by control valves
Regardless of the liquid level, if the liquid level is high, the steam temperature decreases; if the liquid level is low, the steam temperature increases. The pressure is primarily determined by the amount of steam supplied; more steam results in a lower pressure, while less steam leads to higher pressure, as it effectively prevents pressure from dropping. Control your electronic valve to determine the pressure based on the amount of steam delivered.
Thank you! Could you explain why a high liquid level results in a high steam temperature, while a low liquid level leads to a low steam temperature? Also, I think that when the level of liquid in the drum is high, assuming it reaches the maximum full level, the steam generated by the drum should decrease. With less steam, wouldn’t the pressure in the drum drop?
1: The drum liquid level is high, leaving insufficient space for separation between steam and liquid, which makes it easy for steam to contain liquid. 2: A low level of liquid in the drum can cause it to dry out, leading to damage to the equipment. 3: The level of the drum pressure is related to the pressure of the drum feed pump, the drum level control valve, the drum pressure relief valve, and the safety valve. It is independent of the liquid level.
Everyone has made it clear: it has nothing to do with the liquid level. Even when the drum is full, it contains water at the bubble point, and the pressure remains that of the outlet backpressure. The liquid level in the drum is generally controlled to be in the middle range; under normal conditions it fluctuates within a range of just a few dozen centimeters. If the level is too high, steam will carry liquid with it, while if it’s too low, there’s a risk of dry burning (as the vaporization rate in the boiler’s drum is very fast). This post was last edited by xlwhide on 2009-4-17 23:54]