Problems with pre-lifting media

No, it’s possible that over time the catalytic function stopped working, and new modifications were made.

There is indeed a change in diameter; I wonder why it was designed this way?

Is it considering the issue of low riser pressure? ? ? There wasn’t any old catalyst before

After increasing from small to large, the speed and pressure will definitely decrease; what comes to mind is controlling the flow rate and equalizing the pressure； It is also beneficial for the vaporization of certain liquid hydrocarbons, among other things. Looking forward to the best reply

Regarding this issue, I think it’s like this: taking into account the design of our unit, we Predict Improve the dry gas at DN250 and the steam at DN250, but before reaching the bottom of the lift pipe, after the mixing section, the diameter is increased to DN350. In my opinion, during normal operation, both the pre-heated dry gas and steam enter the bottom of the lift pipe to serve as lifting media. However, in abnormal conditions where both the amount of pre-lift steam and the amount of pre-lift dry gas increase, if there is no diameter expansion before the lift pipe after the mixing section, flow cannot proceed, which results in pressure buildup downstream. Is it possible for the two fluids at the front to interact with each other? Furthermore, since the pressure of the dry gas is higher than that of the steam, the result is that the dry gas mixes into the steam; of course, I’m thinking of extreme situations here.