How to choose the position of the sensitive plate of the distillation tower?

When the operating distillation tower is subject to some external interference, such as reflux ratio, feed composition fluctuations, etc., the composition and temperature of each plate in the entire column will change. The most sensitive board or adjacent boards are called sensitive boards. Use the simulation software ASPENPLUS to determine the position of the sensitive plate, and then adjust the position of the sensitive plate according to the quality of the output during actual operation. Under a certain total pressure, the tower top temperature is a direct reflection of the composition of the distillate. But in high-purity separation, the temperature changes very little in a column section that is quite high at the top (or bottom) of the tower. It can be seen that during high-purity separation, the method of measuring the tower top temperature cannot generally be used to control the quality of the distillate. Careful analysis of the temperature changes before and after changes in operating conditions shows that the temperature changes are most significant on certain trays in the rectification section or stripping section. In other words, the temperature of these trays is the most sensitive to external interference factors, so these trays are called sensitive plates. Placing the temperature sensing element on the sensitive plate can detect disturbances to the distillation operation earlier. ； Moreover, the sensitive plate is relatively close to the feed port, so it can sense changes in the feed parameters before the composition of the distillate at the top of the tower changes, and even take adjustment measures to stabilize the composition of the distillate.

In the plate-by-plate calculation of the distillation tower, it can often be found that the composition of a certain plate and adjacent plates changes greatly, so the temperature changes also. When the operation changes, the temperature of this plate changes most sensitively, so this plate is called a sensitive plate. The advantage of using sensitive board control is that: (l) Sensitive change and accurate adjustment. (2) The changing trend of the materials in the tower kettle can be seen in advance and adjusted in advance to prevent light components from being brought into the kettle liquid. Selection of sensitive plates for distillation towers. In principle, the stable operation of the distillation tower depends on the stable monitoring of sensitive plate parameters, which needs to be explored in practice. This parameter is related to your plate structure, processing capacity, material system, operating conditions, the impact of upstream and downstream working conditions, etc.