Flowing problems in the regeneration of catalytic units using inclined tubes

Based on experience, there are several possibilities. 1. The operation status of the fluidization point: whether the allocation is unreasonable, too large or too small, whether there is water present, and whether it is blocked. Second, whether the two-stage fluidization is sufficient, and whether there are any damages or blockages in the main air distributor pipes. Third, check whether the lining is damaged or detached, potentially blocking the valve plate or inclined tubes. Fourth, the heights of the feed inlets for the external circulation and external heat removal inclined tubes are unreasonable, and the catalyst distribution is inadequate. 5. The differential pressure control between the two devices is unstable or too high, resulting in a large catalyst circulation rate. Sixth, the device design is capable of handling large volumes; the air permeation tubes are relatively thick, or a high oil-to-agent ratio is required for production. That’s all I can think of for now.

Apart from equipment-related issues, most cases are caused by excessive fluidization air; closing a few non-critical points appropriately can help determine if this is the issue.

Is it an excess amount of fluidizing air? I think the problem is caused by insufficient fluidizing air; one of the holes in the fluidizing air ring at the bottom of the catalyst cooler has been blocked. This is better than before, but the effect is still not ideal

The first one shouldn’t be it, as each unit is checked for loose parts and the pressure is normal. The second and third ones probably aren’t it either, as maintenance was just completed. As for the fourth one, it needs to be calculated

You yourself said that blocking one every other time yields a better result than before; so do you think the air volume should be more or less than before?

The density of the inclined tubes is too high; the density for dense-phase transport in vertical tubes is between 500 and 750! It is necessary to calculate the amount of loose air flowing into the inclined tubes; Xing Yingchun and Lu Chunxi have a paper on this topic that can be referred to

We also know that this value is relatively high; the key is to find a way to reduce it

I have a few questions: 1. The frequency and magnitude of fluctuations in reaction temperature, and the pressure drop across the slide valve? 2. What is the shape of the outlet of the catalyst cooler? Flood or overflow? 3. Pressure of unpurified air in the device? 4. What is the ratio of the number of loose air streams to the number of loose steam streams in the inclined tubes? 5. Compared to the N2 content in dry gas during the same period, is it higher or lower?

Is it a new installation? Still the old device? Compare the conditions before and after to see what it was like originally. High density is the main reason. If that doesn’t work, then we need to turn to a design firm for modifications!

It’s an old unit; a catalyst cooler was added later as part of modifications. The design agency no longer takes care of it – it’s a small design firm that just leaves after making some money: lol