Heat transfer in a coal boiler?
Heat transfer in a coal boiler?
(OP)
Could any tell me what the heat transfer rate (W/cm2) is in a typical modern coal boiler?
Thanks
Thanks
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Heat transfer in a coal boiler?
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RE: Heat transfer in a coal boiler?
But, if your looking for a ballpark type of figure, I would say that 21 W/cm2 is in the range of typical industrial boilers (about 66,000 BTU/h*ft2).
Paul
RE: Heat transfer in a coal boiler?
RE: Heat transfer in a coal boiler?
I am looking for a ballpark number for the furnace, so your number looks good, Paul. Thanks.
If there are specific technologies (CFB or supercritical?) that provide a greater transfer rate I would be interested in that information as well.
RE: Heat transfer in a coal boiler?
In a furnace the governing phenomena for imposed heat flux is the combustion side process. Due to the high fluxes in a radiant furnace, tube failures due to DNB or psuedo DNB are possible.
For a CFB operating at 1600 F , a max imposed flux of about 31,000 btu/hr ft2 on a bare tube is feasible, but usually the tubes are coated with refractory so the net flux to the tube is lower. These lower CFB furnace heat fluxes make it difficult to fail a tube due to DNB, but failure due to overheat due to dryout or thermal stresses associated with dryout can occur, so it remains important to design the furnace circuit's thermal hydraulic characteristic such that such dryout event occur in a controlled manner.