The problem of easy evaporation in siphon reboilers
Thread Content
There is a one-bedroom siphon reboiler heated by steam; the inlet pipe runs from the liquid collection tank of the lowest tray to the bottom of the reboiler, while the outlet returns to the gas phase space at the bottom of the tower. Currently, the reboiler is constantly experiencing vapor exhaustion (the temperature of the reboiler’s return stream rises above the boiling point of the medium, and the flow rate of the heating steam gradually decreases). What could be causing this?
For such questions, a flowchart is needed; explaining things by referring to the diagram makes it more intuitive. Also, for reference, there is the possibility of issues related to the crystallization of the medium, impurities, or condensation.
The reason may be one or a combination of the following: 1) Leakage from the liquid collection tank of the lowest tray (especially when the evaporation phenomenon occurs and the discharge volume at the bottom of the tower does not decrease significantly)； 2) The tower feed load is significantly reduced ； 3) The backflow volume has decreased significantly ； 4) The operating pressure of the tower has decreased significantly ； 5) The reboiler was recently descaled, leaving excessive free area ； 6) The control characteristics of the reboiler heat source steam control valve are not sensitive enough.
Is it the issue with the liquid phase at the bottom of the tower, caused by the low liquid level?
The outlet returns to the gas phase space at the bottom of the tower ---------------------------------- The liquid level is insufficient; it should be above the return pipe