CostasV
Mechanical
- May 29, 2003
- 126
I am trying to explain (or even better to find a relationship describing) the gas temperature increase in the scraper-trap of a natural gas pipeline system, when it is filled with gas (from 0 bar to 50 bar) wich is supllied from a 50 bar underground (at steady temperature of aprox. 8 deg C) pipeline.
At the end of the filling proccess, the wall of the above-ground scraper-trap was aprox 35 deg C (aprox. 40 on the upper section of the diameter, and aprox. 20 on the lower section of the diameter)
Length of scraper-trap : 20 m
Diameter of scraper-trap : aprox. 1 m
Ambient air temperature : 6 – 8 deg C (= initial wall temperature)
Method of filling : through a 4 inch plug-valve and a (partially open) 4 inch gate-valve, which are connected to the trap with a 100 m long, 4 inch underground steel pipe. The filling, from 0 to 10 bar took about 5 minutes, then for 5 minutes no increase in the pressure (time to check for leaks), and then, about 5-10 minutes to go from 10 bar to 50 bar.
It can not be the P1/T1 = P2/T2, since this law is for steady substance, which is not the case here.
If I remember well, during the filling (from the 50 bar pipeline, through the valves, into the initial “empty” trap), there should be a drop in the gas temperature, not an increase.
What is the main phenomenon in this proccess? How would an increase or decrease in filling time, effect the final temperature?
Costas
At the end of the filling proccess, the wall of the above-ground scraper-trap was aprox 35 deg C (aprox. 40 on the upper section of the diameter, and aprox. 20 on the lower section of the diameter)
Length of scraper-trap : 20 m
Diameter of scraper-trap : aprox. 1 m
Ambient air temperature : 6 – 8 deg C (= initial wall temperature)
Method of filling : through a 4 inch plug-valve and a (partially open) 4 inch gate-valve, which are connected to the trap with a 100 m long, 4 inch underground steel pipe. The filling, from 0 to 10 bar took about 5 minutes, then for 5 minutes no increase in the pressure (time to check for leaks), and then, about 5-10 minutes to go from 10 bar to 50 bar.
It can not be the P1/T1 = P2/T2, since this law is for steady substance, which is not the case here.
If I remember well, during the filling (from the 50 bar pipeline, through the valves, into the initial “empty” trap), there should be a drop in the gas temperature, not an increase.
What is the main phenomenon in this proccess? How would an increase or decrease in filling time, effect the final temperature?
Costas
