External heat exchanger issue
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Is it necessary to install an orifice plate on the lift air below the pneumatically controlled external heat exchanger? That would have a significant impact on catalyst recycling. When I discussed this issue with our supervisor, he said it was to protect against severe wear at the lower part.
What the poster is referring to is likely the fluidized air ring, similar to the distribution tubes (plates) in a regenerator. Its function is also to evenly distribute the pressurized air, preventing flow deviation.
It needs to be added; on one hand, it enables the catalyst at the lower part where heat is extracted to become more fluid, preventing localized flow patterns that could cause localized wear on the heat extraction tubes. Another aspect that also facilitates catalyst fluidization is that the pore size of the flow control orifice plate in this section should not be too large. Be careful it might have the opposite effect. It can be seen during maintenance.
I would like to ask Haiyou: what is a pneumatically controlled external heat exchanger, and how does it work? Is it easy to control?
You must be referring to what is used for distributing the fluidizing air; the main purpose is to prevent the catalyst from accumulating in one place. The Luoyang Institute does not use control valves for this purpose – a hole plate is sufficient, acting as a means to loosen things up. The boost wind is used to regulate the catalyst circulation rate; this is what is meant by gas-controlled operation. However, it’s very difficult to regulate the heat absorption; its flexibility in adjustment is much worse compared to those with slide valves, and it seems to be used less these days.
Thank you, OP; it’s the first time I’ve heard about this.