August 19, 2009 at 6:35 am #3020
Hello. Does anyone what would happen if the quench water control valve failed wide open at the beginning of the quench cycle? Would the 1600 gpm of water totally vaporize and result in lifting the PSVs that go to the blowdown drum?
August 20, 2009 at 10:39 am #6027
If you have one 1600 GPM pump and the control valve is “fail open” then it could happen.
Some cokers have 2 or 3 pumps to handle the total max quench water flow. (You start quenching with one pump and then turn on additional pump(s) as required.
You can also have one 1600GPM pump with two control valves in paralell set up each to handle 800 GPM when completely open. These should be set as “fail closed”
Hope this helps.
August 20, 2009 at 11:44 am #6026
The use of 2 valves is not a good engineering practice
August 20, 2009 at 2:21 pm #6025
What about if one valve was much smaller than the other valve. The small valve is what would be opened first, and then once the coke is cool enough, the larger control valve would be opened. Would that be good engineering practice? What if the opening of the valves was a manual procedure?
August 25, 2009 at 10:12 am #6022
antonio saura CebrianParticipant
The typical design for these units are two valves in parallel, their design can be handled half the total flow of cooling, in the designs of FW, usually by placing a valve that handles between 20 to 30% of flow total and the other manages the total flow, this helps manage low flows (Rangeability) and when this is fully open the other begins to operate. Cooling ramps can be automatic based on the cooling curves of the drums, usually tries to maintain small flows in the early hours and avoid problems of stress on the drums, there are additional protections to detect high pressure in the drum during this stage that stop the quenching pumps
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