【Refining】The difference between fixed-bed and fluidized-bed reactors in petroleum refining
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This post was last edited by Xiao Gong 1985 on 2016-2-18 at 11:01. Dear experts, what are the specific differences between fixed-bed and fluidized-bed reactors in the refining process? I’m new to this industry and don’t know much; could you please advise me?
Find a book on principles of chemical engineering; it covers all the most basic knowledge
A fixed-bed reactor features grids or screens at the top and bottom to hold the catalyst in one area; the catalyst in a fixed-bed reactor must be shut down or removed in order to be regenerated. In a fluidized bed, the catalyst is continuously flowed (or stops and flows in short intervals) between the reaction zone and the regeneration zone for exchange.
Thank you, I now understand better. I was wondering if anyone has actual photos I could take a look at, hehe
It’s what I read in books; I don’t quite understand it, that’s why I came to the forum to ask!
Fixed-bed and fluidized-bed are terms used to differentiate catalysts; in a fluidized-bed system, the catalyst is always in a state of fluidized boiling, and a force is required as a driving mechanism to maintain this fluidized state. A fixed bed is a \"dead\" bed, which is held in place on a bed layer by fixing components at both ends. Fixed-bed reactors can also be regenerated inside the reactor itself; for example, the catalysts in aromatization units are regenerated within the reactor.
I had been struggling with the idea that the \"bed\" he mentioned is similar to the beds we use in our daily lives, having a fixed shape and structure. Now that I hear you explain it this way, it can be understood as a reaction process between a catalyst and oil and gas; when this process and its scope remain fixed, it’s called a fixed-bed reactor, while when these aspects are variable, it’s called a fluidized-bed reactor. I’m not sure if this understanding is correct
The catalyst in a fixed-bed reactor remains stationary (usually in spherical form), whereas the catalyst in a fluidized-bed reactor is in a \"suspended\" (fluidized) state and is in dynamic flow (as fine particles, similar to sand). The amount of catalyst in a fluidized-bed reactor can be adjusted within a certain range
Are the particle sizes of those catalysts also very different? The spherical catalysts used in fixed-bed systems are relatively large; is there any specific description of their size? Those used in fluidized-bed systems are similar to sand in size
The catalysts in the fixed-bed are about the same size as the glass beads we used to play with as children
Uh, I see. Thank you. The catalyst in a fixed-bed reactor is located in a fixed space and can’t move, right?