How to solve gas-phase short circuit in a floating valve tower?
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No experience in commissioning unit float valve towers. The light components in the feed solution are less than 1%; full reflux operation was used during testing. However, the gas phase in the tower entered the upper trays through the downcomers, and the liquid phase failed to cover the overflow weir, resulting in severe leakage. I would appreciate some guidance from those with more experience.
This post was last edited by wiseboy on 2012-2-26 20:26. It seems that fluid dynamics design wasn’t taken seriously again, and the consequences of underestimating technical aspects are evident. This issue must have arisen from a lack of fluid dynamics calculations (hydraulical calculations); it was decided based on guesswork. Only the internal components need to be replaced: the tray and downcomer were redesigned, manufactured, and installed.
The tower was designed by a commissioned design institute. Is there a problem with the manufacturing process? Can it be resolved by modifying the process? Please give me your guidance.
Without detailed calculations, it can be seen that first of all, the diameter of the distillation section of this tower is smaller than that of the stripping section, or the open area ratio of the distillation section is much smaller than that of the stripping section. Assuming the design is correct, it is necessary to check whether the side plates of the downcomer are welded to the tower wall. The author once built 3 tower systems for a private factory, yet that manufacturing plant failed to weld the downcomer side plates to the tower wall. Fortunately, I caught this silly mistake before driving; otherwise, it would have ended up like what you encountered. Please send back a letter with the results of the inspection.
The liquid inside the tower must not be exposed to air; opening the manhole for inspection constitutes a major repair, and this situation cannot be seen through the sight glass installed on the tower. Through the sight glass, it can be seen that a large amount of gas-liquid mixture is rising up from the downcomer.
This post was last edited by DXJ122 on 2012-2-26 at 17:38. Of course, it’s impossible to see the welds if the manhole isn’t opened. 1 Currently, the only thing to check is the drawings to see if weld symbols are indicated for the downcomer and the tower wall. It should be a continuous welding symbol; it is suspected that there is no welding or the welding is intermittent, which is why the gas flows in a short circuit. 2 Please have the manufacturer locate the records of the welding completion and speak with the welders involved. 3 Can the sight glass be used to see the liquid level on the plate? If welding issues are ruled out, then try to find the cause.
I’ll go check the drawings tomorrow. The sight glass clearly shows that the liquid level on the plate does not cover the overflow weir. However, I don’t think this is the main reason, because it can be seen through the sight glass that the gas-liquid mixture is rising up through the downcomer, and the downcomer fails to form a liquid seal.
May I ask how such a conclusion was reached! Which parameters indicate the conditions inside such a tower!
Observed through the sight glass installed on the tower: 1. The liquid level on the inner plate of the tower did not cover the overflow weir. 2. The gas-liquid mixture rising up through the downcomer. 3. The downcomer failing to form a liquid seal. All of these can be seen directly through the sight glass.
This post was last edited by wiseboy on 2012-2-26 20:25. “It can be seen through the sight glass that the gas-liquid mixture is rising upward through the downcomer; the downcomer fails to form a liquid seal,” which indicates that the liquid level in the downcomer is not high enough. If there are no obvious manufacturing errors, it is a defect in the fluid dynamics design. I work at a major design institute, and I am well aware of the current level of expertise in tower fluid dynamics design within such institutions.
Is it possible that it’s a problem with the manufacturing process? If so, how should it be adjusted? After all, to prove that there is a problem with the design, solid evidence is needed. How can one prove that it’s a design issue?