Question: What is the purpose of installing solid valves locally on the trays of a catalytic cracking fractionation tower?
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I would like to ask everyone: in the catalytic cracking fractionation tower, there are 29 trays, with secondary reflux to the tower; 11 rows of fixed valves are installed at equal intervals, while the rest are floating valves. What is the purpose of this design?
Since the medium returning to the tower flows downward toward the tray, it affects the rise of the floating valves, which in turn influences the upward movement of the gas phase and the downward movement of the liquid phase; therefore, some fixed valves are generally installed.
Thank you for the answer. But why is it not required at the position where the first stage returns to the tower or at the top-of-the-stack return point?