Blow Down Line Temperature Change
Blow Down Line Temperature Change
(OP)
Hi everyone
Pls. help me with the following problem. There is 10 feet long and 4" in diameter blow down line coming out of LPG heat exchanger and I need to figure out the line temperature change along the line as result of opening block valve from this pressurized LPG heat exchanger to blow down system.
Pls. help me with the following problem. There is 10 feet long and 4" in diameter blow down line coming out of LPG heat exchanger and I need to figure out the line temperature change along the line as result of opening block valve from this pressurized LPG heat exchanger to blow down system.





RE: Blow Down Line Temperature Change
hope this helps
RE: Blow Down Line Temperature Change
Adiabatic Flash across an orifice is isenthalpic. Pick up the enthalpy of the liquid before flash, then pick off the same enthalpy at the new pressure downstream. THere's your temperature. Also will reveal quality of the 2-phase flow.
RE: Blow Down Line Temperature Change
RE: Blow Down Line Temperature Change
But if you really require to know the exact temperature 10 Ft away from the source, which is not far by the way, then you'll have to do a heat loss calculation to calculate how much heat will be transferred from the sorrounding, taking into account any insulation that is there,pipe thikness and diameter, wind velocity, minimum ambient temperature, etc, etc, into the pipe..
RE: Blow Down Line Temperature Change
RE: Blow Down Line Temperature Change
and your piping downstream depressurization made of carbon steel it can tolerate up to -29 C
all calculation show not below -10 to -20 C minimum temp.
except your upstream system 600# including higher (900#,1500#) your let down can reach lower -29 C so, next step of material just change to SS which main handle -45 C..
this is overview for your view.
RE: Blow Down Line Temperature Change
So as to explore certain Carbon steel's potential with -40 degrees Celsius withstanding capability.
As used for many LPG storage bullets manufacture.
Hope this helps.
Best Regards
Qalander(Chem)
RE: Blow Down Line Temperature Change
The thing to pay attention to is piping stress due to line contraction.