How are the temperatures at each layer of the distillation tower maintained and controlled?
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The azeotropic unit in our company uses multi-effect distillation, with a total of 60 trays, and the temperature of each tray is different. Keeping it under control is key! ~
Is it related to the liquid of the follow-up material? The bottom is heated by steam at 0.4 MPa. If you have any other questions, just ask.
The location of the temperature control points in a distillation tower: If the overhead distillate is the main product, temperature monitoring points that indirectly reflect quality should be placed at the top of the tower, thereby forming what is known as a temperature control system for the distillation section； Similarly, to ensure that the product at the bottom of the tower meets quality requirements, temperature monitoring points should be placed at the bottom of the tower, and a temperature control system for the stripping section should be implemented. A cutting tower with a crude distillation function; in this case, the location of the temperature monitoring points should be determined based on the required level of purity of the product. Medium-temperature control: Place the temperature detection point on a tray near the feed plate. The purpose is to detect the movement of the operating line in a timely manner, taking into account the changes in the components at the top and bottom of the tower. When the top (or bottom) temperature is used as an indirect mass indicator, in practice, it is very rare to place the temperature sensor at the top (or bottom) of the tower. Instead, the temperature detection point is placed on the sensitive plate between the feed plate and the top (bottom) of the tower. The so-called sensitive plate is the one whose composition changes when the column is subjected to disturbances or control actions; as a result, the temperature of each tray in the column also changes. When a new steady state is reached, the tray with the greatest temperature change is the sensitive plate. The approximate position of the sensitive plate is determined through calculations first; thereafter, multiple detection points are set up in its vicinity, from which the best measurement point is selected as the sensitive plate.