Increase the speed of the lift pipeline in the catalytic cracking unit
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How are the linear velocity of the lift pipe in a catalytic unit and the reaction time calculated? What range is generally considered normal for these values?
You should look at the reference books yourself; this calculation is quite complex. Different devices have different design line speeds, and these line speeds are related to the length of the lift pipe. In the design, the residence time is the main factor to consider; it must meet certain requirements, generally within 3 seconds, though I’m not entirely sure of that figure. The residence time for heavy oil catalytic cracking is even shorter, around 1 second.
The last edit to this post was made by 328104062 on 2011-8-24 at 15:46. Reply to 1#: For trace elements, the calculation of the linear velocity is the logarithmic average of the inlet and outlet linear velocities; this is explained in many sources, in the section on fluidization
Reply to 3# 328104062: It is generally between 15-25 m/s, with a reaction time of 1-3 seconds; 2 seconds is the most common value
The linear velocity in the rising section is 3–8 m/s, while it is 12–18 m/s after the reaction section; generally, the reaction time in the lift pipe is 3–4 seconds.