Distillation column pressure control translation
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Background: When the pressure in a distillation column is low, one possible reason is excessive cooling of the top condenser, which results in a too low reflux temperature. The condenser at the top of the tower now uses an air cooler, and the condensation temperature is automatically controlled by a variable-frequency fan; the faster the fan speed, the better the cooling effect, resulting in a lower condensation temperature ； The same is true in reverse. (Of course, the lowest condensation temperature is limited by the ambient temperature.) Below are the recommended solutions. Reduce fan speed to allow the column overhead pressure to rise to its set point where automatic control can resume. This sentence appears several times in our manual, but none of the translations are satisfactory; are any of you interested in giving it a try?
Reduce the fan speed so that the pressure at the top of the tower can reach the set point for automatic recovery. I’m not sure if it’s smooth
Reduce the speed of the fan in the top air cooler to decrease the amount of condensation, thereby raising the pressure at the tower top back to the set operating value and restoring automatic control. (Sometimes, to make the translated sentence complete and easy to understand, some explanations can be added appropriately.)
The translation upstairs is good; actually, the mistake in our manual’s translation lies in the phrase “where automatic control can resume”. The corresponding actual DCS operation is: switch the fan speed controller to manual mode and gradually reduce the speed; once the pressure starts to rise and stabilizes at the set value, switch the fan speed control back to automatic mode.