Heat Transfer in Above Ground Gas Pipelines
Heat Transfer in Above Ground Gas Pipelines
(OP)
I am trying to gauge the effect of not insulating a straight section of pipework upstream of an orifice meter. In particular I wish to determine the effect of ambient air on the flowing gas temperature. The pipeline is 24inch I/D with a 0.75inch wall thickness. Typical natural gas temperature is 8 oC to 15 oC, with an average flowrate of 265 Ksm3/h (194 t/h).
Any ideas would be most appreciated.
Any ideas would be most appreciated.





RE: Heat Transfer in Above Ground Gas Pipelines
RE: Heat Transfer in Above Ground Gas Pipelines
Many thanks "quark" for your previous fast response.
RE: Heat Transfer in Above Ground Gas Pipelines
take Cp=2000 J/Kg°C for the gas, this makes about 100 kW the power that must be lost by the flowing gas to decrease its temperature of 1 °C.
Now take h=20 W/m2°C as the heat exchange coefficient to air and some Δt=20 °C as the maximum temperature difference. One meter length of pipe, with outer surface area of nearly A=2 m2 will lose hAΔt=800 W. This means that 100 meters of uninsulated pipe would make a temperature change of only 1 °C: this seems to me quite negligible, but don't know what are your limits.
It is also to be noted that the effect of sunlight is not included in the above calculation, and, if present, wouldn't give a negligible effect.
prex
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