Reformation catalyst enhancement
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The continuous reforming unit at France’s IFP separates the gas stream into primary gas and secondary gas. I would like to ask everyone: does the primary gas serve the purpose of fluidization, while the secondary gas is used to control the flow rate? Or does the secondary gas function for fluidization and the primary gas control the flow rate? My personal opinion is 1√. The reason is that the secondary gas carries the catalyst to above the nozzles of the primary gas, where it is dispersed by the primary gas, thus achieving fluidization; the amount of catalyst carried by the secondary gas itself controls the flow rate of the catalyst. Then, both the primary gas and the secondary gas work together to transport the catalyst to the upper hopper. However, some argue that the function of the primary gas is to control the flow rate; in other words, the secondary gas carries the catalyst to the primary gas nozzles, and as much catalyst as is sent there is also blown away (transported), so the primary gas is used to control the flow rate of the catalyst.
Hello, my friend. In the case of UOP, primary air is blown in from below to loosen the catalyst, while secondary air is blown in from the sides; its role is to fluidize the catalyst. Then, the primary air and secondary air combine to lift the catalyst together. I’m not sure if what I said is correct; please advise
The L valves from UOP and the lift gases from IFP work on the same principle; I think you’re absolutely right. However, there is another view now, and it’s hard to say who is right and who is wrong.
One-stage gasification, two-stage gas flow control – no apparent issues here
The first gas blows the catalyst up, while the second gas is used for transportation
The secondary gas determines the catalyst flow rate, while the primary gas accelerates and transports the catalyst. A certain ratio between the secondary gas and the primary gas is necessary; otherwise, if the amount of secondary gas is too high, too much catalyst will be conveyed into the flare mouth. If the amount of primary and secondary gas is not sufficient to fluidize and transport this catalyst, it will lead to uneven distribution of the catalyst within the catalyst delivery pipeline, preventing proper fluidization and preventing it from reaching the upper buffer hopper. As I understand it, the secondary air flow should be smaller than that of the primary air, so as to ensure that all of the catalyst that has been agitated by the secondary air flow can be accelerated and transported
I think if you’ve seen the structure of the lifting hopper, you won’t be confused by this issue. The lifting hopper has a double-walled structure; the primary air pipeline extends deep into the lifting pipeline, and its main function is to provide power for lifting the catalyst. The secondary air is located between the two walls, with an annular space surrounding the primary air pipeline. The flow of secondary air is used to fluidize the catalyst, that is, to disperse it, after which the catalyst is lifted by the primary air to the upper buffer hopper of the next reactor. It should be noted, however, that if the amount of primary air is too low, the catalyst does not have sufficient force to rise upward; if it is too high, the linear velocity of the catalyst becomes too fast, resulting in severe wear of the catalyst. Generally speaking, the linear velocity of the catalyst should not exceed 2 m/s. I hope the answer is helpful to you.
When the secondary air is turned off, the primary air cannot lift the catalyst; but when the primary air is turned off, the secondary air can lift it