Heat emission from steam or water heating pipes submerged in oil or fat - forced and natural circulation.
The viscosity of a fluid has considerable influence on the heat transfered from a submerged heating pipe. Be aware that the viscosity of a fluid is highly dependent on the temperature.
Heat emission from steam pipes submerged in oil baths are indicated below:
|Application||Fluid||Heat Emission from coil surface|
|(Btu/ft2 hr oF)||(W/m2 oC)|
|Steam coil with medium steam pressure and natural convection of oil||Light Oils||30||170|
|Heavy Oils||15 - 20||85 - 115|
|Fats||5 - 10||30 - 60|
|Steam coil with medium pressure and forced convection of oil||Light Oils||100||570|
- Light oils - 220 SSU at 100 oF
- Heavy oils - 1100 SSU at 100 oF
- Fats - 3833 SSU at 100 oF
- Carbon, Alloy and Stainless Steel Pipes - ASME/ANSI B36.10/19 - dimensions
- Outside surface area - pipe equations
Example - Heat Emission from a 2" Coil in a Fat Tank
A 10 m long 2" inch stainless steel steam coil heats a tank with fat. The steam pressure is 1 bar and the temperature in the coil is 120 oC. The temperature in the tank is 40 oC. The convection is natural with heat emission 50 W/m2oC.
The outside diameter of the pipe is 60.3 mm and the external surface of the pipe pr. m length of pipe can be calculated as
As = 2 π ((0.063 m) / 2) (1 m)
= 0.2 m2/m pipe
The heat emission from the coil as whole can be calculated as
Q = (10 m) (0.2 m2/m pipe) (50 W/m2oC) ((120 oC) - (40 oC))
= 8000 W
= 8 kW