Heat transfer coefficient for super heated steam 2

[ProcssMan]

I am proposing to switch from saturated to superheated steam for a long distance steam transport system. Can any one let me know where I can find the Heat transfer coefficient (W/m^2K) for both saturated and superheated steam to calculate the heat loss in both cases. Transmission pressure is 9700 kpa, thanks

 

[srfish]

The heat transfer coefficient for the superheated steam will depend on velocity. I would use the heat transfer coefficient for the condensing steam a value of 2000 Btu/ft2-h-F.

 

[ProcssMan]

I understand heat transfer coefficient for saturated steam will depend on temperature also. In case of Super heated steam it will further depend on the degree of super heat. Heat transfer coefficient in case of Superheated steam is way lower than (condensing) saturated steam, generally in order of magnitude.
Is 2000Btu/ft2-h-F corresponding to 9700 kpa?
If not can I find a chart or a tool which will provide me the heat transfer coefficient for both saturated and super heated steam at various pressures and temperatures, Thanks!

 

[ProcssMan]

Sorry, saw a typo above. Please read ".. heat transfer coefficient for saturated steam will depend on pressure also..."

 

[georgeverghese]

Do you have a copy of DQ Kern's Process Heat Transfer or Perry's Chem Engg Handbook or any other heat transfer text ? All information required to derive these coefficents for the operating press / temp ranges of interest may be found in these books. Also add a suitable fouling coeff if applicable.

 

[davefitz]

There are many sources for correlations for heat transfer coefficient, but it is irrelevant if you add insulation to the pipe for most practical sizes of pipe. The net heat transfer will be a function of the sum of the thermal resistances of the inside convective , pipe wall, outer insulation, and outer surface convective + radiation. The value of the insulation resistance overwhelms and makes irrelevant the other resistances.

"...when logic, and proportion, have fallen, sloppy dead..." Grace Slick

 

[georgeverghese]

@davefitze, Agreed, steam side htc (whether this be condensing or single phase forced convection ) is somewhat negligible in terms of heat transfer resistance in comparison to that presented by insulation layer and external insulation jacket radiation. This should simplify the calcs considerably with little loss in accuracy on total heat loss/ linear m of pipe.