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My unit is equipped with a distillation column AS-106; it features floating valve trays and has 16 trays in total. The feed inlet is located on the 10th tray, while the sensitive tray is on the 2nd tray. The operating pressure is 22.3 kPa (absolute pressure). The reboiler at the bottom of the column operates under forced reboiling conditions, with a circulation rate of 45,000 kg/h. The designed top temperature of the column is 130–136 degrees； Sensitive plate 190-210 ； The bottom of the tower is 224-230. Recently, it was observed that both the temperature at the bottom of the tower and the temperature of the sensitive plate decreased simultaneously. Currently, the temperature of the sensitive plate is 163, while that at the bottom of the tower is 212 – these values are quite far from the design values. However, the temperature at the top of the tower remains stable at 133. During the adjustment process, various measures were tried, such as changing the circulation rate at the bottom of the tower, increasing the flow of reboiling steam, and reducing the reflux flow. After each adjustment, the temperatures of the sensitive plate and the bottom of the tower increased by 2–3 degrees, but after some time they dropped back to their previous levels. It is currently suspected that the separation efficiency has decreased due to the detachment of trays in the distillation section. Since it is winter at present, it is not possible to shut down the plant for repairs. The issue of changes in the composition of the feed material can be ruled out, as the feed for this tower comes from the bottom of distillation column AS-105, and the temperature at the bottom of AS-105 remains stable at the design value; therefore, there is no possibility of a change in the composition of the feed. I’m seeking advice from my colleagues: if it’s not the tray that has come loose, are there any other adjustments that need to be made? Thank you.