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Why are most coker furnaces box type with horizontal tubes? Coker furnace heat duty is comparatively lower than a crude heater's, still they are horizontal ones. We have 9 heaters in our refinery for a coker with all of them as horizontal types. Any ideas on selection criteria ?
 
Answers
21/02/2020 A: Bruce Carr, Suncor Inc, bcarr@suncor.com
The tubes are normally smaller diameter and horizontal.... The smaller diameter increases the velocity that along with velocity steam allows the oil to absorb the heat but delays the coking until it reaches the Coke Drum... that's why its called Delayed Coking.... Also I'm sure your outside burners are Wall Burners that produce a flat flame that heats the refractory. It's the refractory that radiates the heat to the tubes. You get a more even heat distribution with horizontal tubes..
21/02/2020 A: RUPAM MUKHERJEE, ENGINEERS INDIA LIMITED, rupammukherjee86@gmail.com
Coker feed is heavy. The criteria is to go for a horizontal tube furnace to minimize flux imbalances and to promote more natural flow tendency. Vertical tubes might not be good idea for such heavy coking services. Hence you find horizontal box furnaces.
21/02/2020 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
Getting uniform heat flux to minimize coking in the heater tubes is critical. You can accomplish that goal much more effectively in a horizontal box type of furnace.