Why are the liquid levels at the bottom of the distillation tower experiencing regular and significant fluctuations?
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The liquid level at the bottom of the distillation tower fluctuates greatly, yet in a regular pattern; meanwhile, the steam flow rate and tower pressure also exhibit regular fluctuations. What is the reason for this?
It is recommended to reduce the load until it stabilizes and remains within a controlled range, so that a new operating condition can be established. Problems can be exposed during this process.
Is it caused by the steam flow? ? ? ?
Examine the changes in various quantities under stable and unstable conditions to identify the causes.
The feed rate, reflux rate, and heat source at the bottom of the tower can all cause such fluctuations. It is necessary to determine the cause by examining the variation curves of other variables prior to the fluctuations; it’s not possible to make a determination based solely on this curve
The causes need to be investigated from various aspects: bottom temperature, top temperature, top pressure, reflux volume and its temperature, feed rate, feed temperature, and changes in feed composition. There can be a variable, with the other quantities remaining constant, to identify the influencing factors one by one.
Try reducing the load to see how it performs under low-load conditions. This may be related to heating–condensation–backflow; perhaps one of the variables has reached its operational limit.
It is recommended to check previous operation records to compare the backflow volume, steam volume, and feed volume, to determine whether flooding occurred due to a high load without timely adjustment of the ratio tower. It is also possible that the return steam, or the reading of one of the key indicators, is inaccurate; the actual value is too high, which disrupts the stability of the tower.
It is recommended that you put all these parameters that people mention on one screen, so as to see which parameter’s fluctuations cause subsequent changes. The parameters influence each other, and it’s important to determine the sequence of events!