The temperature rise in the second bed of the cracking reactor is higher than that in the third bed – the adjustment mechanism!
Thread Content
Yesterday, the temperature of the hydrocracking reaction was increased; the temperature rise in the second bed of the cracking reactor was greater than that in the third bed. What methods can be used to quickly reduce the temperature of the second bed? Please explain the specific theoretical basis. Participants receive financial rewards
I would like to ask, what problems could arise if the temperature rise in the second bed layer is higher than that in the third bed layer? If simply reducing the temperature of the second bed layer can produce cold hydrogen
Hehe, that’s what I really think too – use cold hydrogen
The temperature rise per bed is related to both the type of catalyst and the packing density.
Hehe, I’m not too sure about this either
Adjust the bed temperature appropriately; when the third bed layer’s temperature decreases, the second bed layer’s temperature will also decrease
Adjust the inlet temperatures of each bed appropriately, and by regulating the cold hydrogen, ensure that there is an appropriate temperature gradient across each bed
This post was last edited by twinkler on 2013-3-12 at 18:37. If cooling with hydrogen in the second bed layer does not solve the problem. You can try the following steps! Reduce the feed temperature, thereby lowering the outlet temperature of Bed 1; lower the temperature rise in Bed 2 by appropriately reducing the amount of cold hydrogen used in that bed; and increase the inlet temperature of Bed 3, thus raising its temperature rise.
It depends on the quality of your product; product quality is of primary importance. Secondly, it’s necessary to consider the flow rate of cold hydrogen – if it’s not above 50, considering reducing the inlet temperature of the second cracking bed might be advisable. If the flow rate of cold hydrogen is high, then reducing the temperature of the previous bed layer could be considered.
If the catalyst type and bed height are not taken into account, the reason for the increased temperature in the second bed may be that the activity of the catalyst in the first bed is suppressed (as it comes into contact with the refined oil first and may be adsorbed by impurities such as organic nitrogen), resulting in most of the cracking reactions occurring in the second bed and thus an increase in temperature. Therefore, it is necessary to open the cold hydrogen valve at the inlet of the second bed layer to reduce the inlet temperature, thereby lowering the outlet temperature of the second bed layer and preventing the cold hydrogen valve at the inlet of the third bed layer from being opened too wide. (The cold hydrogen valve is generally best set at 20–30% opening for emergency use.)
The inlet temperature of the second reactor can be reduced in order to lower the temperature rise in the bed; cold hydrogen can be used at the inlet, or the temperature rise in the bottom layer of the first reactor can be decreased. Efforts should be made to keep the temperature rises in each reactor as uniform as possible, in order to prevent excessive temperature increases that could lead to runaway temperatures in the bed and cause catalyst carbon deposition and damage.