Internal component issues in hydrocracking reactors
Thread Content
We have consistently found that there is cold hydrogen between the bed layers, and the exit temperature of the upper bed layer is much lower than the inlet temperature of the lower bed layer, which is somewhat puzzling. Upon closer inspection of the positions of the thermocouples and the cold hydrogen pipes at the site, it was found that the thermocouple measuring the temperature at the bed outlet is located relatively close to the cold hydrogen pipe, essentially on the same horizontal level. It is understood that the internal structure features thermocouples and cold hydrogen tubes at the top and bottom of the grid respectively. Is such a design good? What are the specific reasons for the above situation? I hope experienced experts can provide guidance, or that everyone will actively discuss and share their own experiences.
It’s probably because it’s too close to the cold hydrogen tube; the temperature compensation of the thermocouple has gone wrong! In my opinion
All the hydrogenation reactors here are like this; it’s probably not the issue mentioned by the original poster
What is the maximum difference between the exit temperature of the upper bed layer and the inlet temperature of the lower bed layer? 1. Conduct an experiment: With all other conditions unchanged, observe the change in temperature difference by varying the amount of cold hydrogen. 2. Location of the thermocouple at the inlet to the lower bed layer. If this thermocouple is very close to the redistribution plate beneath the cold hydrogen tank, then the temperature difference may be caused by the cold hydrogen ； If this thermocouple is located far from the redistribution plate beneath the cold hydrogen tank (i.e., the temperature measured is that of the hydrocracking catalyst), a large temperature difference can be understood ； 3. The method for comparing the \"exit temperature of the upper bed layer\" with the \"entry temperature of the lower bed layer\" should not involve comparing the \"minimum value of the exit temperature of the upper bed layer\" with the \"maximum value of the entry temperature of the lower bed layer\"; doing so would take the radial temperature difference into account as well, thereby increasing the difference ； 4. Type of thermocouple: 120-type distribution or ring thermocouple?