Problems with the catalytic regeneration system
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May I ask a senior: In a catalytic two-stage regeneration riser catalytic unit with high and low levels arranged side by side, why is steam used for fluidizing the reverse blowing in the regeneration inclined tubes?； Is the backwashing of the circular inclined tubes done using purified air?
The steam fluidization used for backblowing in the regenerative inclined tubes is primarily intended to prevent excessive air from entering the settler, thereby avoiding accidents. In some units, the air used to aerate the regeneration inclined tube before the regeneration slide valve is also unpurified air, but the orifice plates used must not be too large. The reason is the same as above. All the loose points after regenerating the slide valve are fluidized with steam. The purge air used for cyclic inclined tube backwashing is purified air, as the regenerator system already uses air for coking; therefore, it doesn’t matter if air is used for fluidization. However, ordinary devices use unpurified air.
I agree with the comment above; to add something, using compressed air as the process medium yields better results compared to steam.
Steam is used for backblowing the regenerative inclined tubes to prevent air from entering the reaction system; this is done both for safety reasons and to reduce the amount of non-condensable gas in the reaction system, thereby easing the burden on the rich gas compressor. The regeneration loop pipeline is part of the regeneration system, and using air eliminates the aforementioned problems.
What was said on the 2nd floor is great; I agree.
The opinions on the 2nd floor are better; I’ve learned from them
The most basic requirement for operating these two units is to prevent air from entering the reactor, and to prevent oil and gas from entering the regenerator. The use of steam flow to flush the regenerative inclined tubes is intended to avoid excessive air from entering the settler, which could lead to accidents. Generally, the regeneration inclined tubes in front of the regeneration slide valve are fluidized with air, while those in front of the unregenerated slide valve are fluidized with steam, all for safety reasons. The purified air is used for the cyclic inclined tube backwashing, as the regenerator system already uses air for combustion; therefore, it doesn’t matter if air is used for fluidization. Using purified air also helps to reduce the amount of water that enters the regenerator, thereby protecting the catalyst.
The most critical aspect in operating a catalytic cracking unit is to avoid cross-contamination of oil and gas between the two reactors; I agree with the answer from the second floor.
The main purpose of using steam as the medium to loosen the joints is to prevent wind from entering the settler and causing accidents