How to protect catalytic dense-phase superheaters
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This post was last edited by Refiner on 2018-12-30 at 13:42. How do you provide protection in the event of an accident involving the catalytic steam dense-phase superheater? At 3.5 MPa, saturated steam is superheated in the dense phase of the catalytic regenerator to become 3.5 MPa superheated steam. In the event of an accident, the catalytic unit does not produce steam itself, and without any steam entering the steam superheater, over-temperature conditions can easily occur. How do you address this issue?
I’m sorry, I didn’t explain it clearly; it’s the steam superheater
I’m sorry, I didn’t explain it clearly; I’ve added the topic content now
We had them there too before; because they kept leaking, we ended up removing them altogether! Even without this superheater, we didn’t observe any over-temperature during the accident; the flow rate and temperature were reduced, so over-temperature should basically not occur!
I have seen both internal and external heat extraction methods; however, I have not encountered a design that uses the bed layer to heat saturated steam. Isn’t it usually the heating furnace or the flue gas from auxiliary boilers that is used for heating? High-pressure steam can be cooled and depressurized to produce superheated medium- and low-pressure steam. Besides, I’ve never heard of a design where the steam pipeline system is linked to the shutdown of catalytic cracking units. If no steam is produced within the unit, then steam can simply be supplied from elsewhere; continuing to supply steam should work fine. If that’s not possible, then such a design is truly unbelievable. This is essentially still a heat exchanger, not a lining or furnace wall; burning it at high temperatures without any coolant will definitely cause problems. :L
It’s the internal heat exchanger; in case of an accident, it reduces temperature and flow rate, allowing things to be maintained
During design, a supply of 1.0 MPa protective steam should be provided; in such cases, this steam is directed to the superheater and vented at the outlet. But some superheaters are made of high-quality materials that allow them to operate without fuel, in which case there’s no need to worry about them.
That is, there should be a low-pressure protection steam line after the superheater valve; it can be opened in case of an accident to allow steam to be vented and thus protect the superheater tubes.
There is 1.0 MPa of protective steam available, but it is necessary to close all the inlet and outlet valves of the dense-phase steam superheater and then open the outlet for venting. This is a rather labor-intensive process, and it’s inconvenient to do so when there are few people available in an emergency situation. Therefore, I’m asking if anyone has any good suggestions