3 replies to this topic

[Ariel]

Hi!

I have question. Is not a process problem for us but is something that catch my attention and  I need help to explain.

First of all, we saw a water condensation (from ambient humidity)  over the pipe as show in “Condensation path”.

An 18inches pipe in transporting natural gas and a condensation “path” can be seen where a 2in sidestream get into.

 

Operating Condition:

 

18” inches pipe

Pressure: 2.5 kg/cm2g (28.4 psig)

Temperature: 0-2 °C (32-28°F)

Flow: 1 MMSMCD (35 MMSCFD)

Molecular Weight: 19 (See Composition MW19)

Service: Natural Gas from Field

Ambient Temperature: Between -2 – 15°C (28-59 °F) Winter Here.

 

2” inches pipe

Pressure: 2.5 kg/cm2g (28.4 psig)

Temperature: 24 °C (75°F)

Flow: 3100  SMCD ( 105.900 SCFD)

Molecular Weight: 35 (See Composition MW35)

Service: Gas from Condensate Stabilization Column

Ambient Temperature: Between -2 – 15°C (28-59 °F) Winter Here.

 

 

We use a infrared camera to see temperature profile inside the pipe. It can be seen that the coldest temperature is just in the gas mixing zone, drawing the same path as condensation appears. See “infrared Picture”.

There´s any chance that, when I mix two different molecular weight gases, a kind of condensation happened taking energy from ambient? How can I explain that?

 

Thanks in advance!

Ariel

Attached Files

•  Infrared Camera.JPG   39.63KB   2 downloads
•  Condensation Path.jpg   249.35KB   1 downloads
•  Composition.xlsx   11.41KB   4 downloads

[Ariel]

Additional information:

The 35MW gas, exit from the top of the tower at 50°C (122°F). The pipe is bare and long (80m/262f above ground, 90m/295f buried) and the ambient temperature is by far colder that 50°C (122°F), so maybe condensation that has been happening at the pipe “flash” when mix with a light MW gas. Could be that “flashing” the cold temperature explanation?

 

Thanks

Ariel

[Bobby Strain]

Maybe you should start by checking the air temperature where the frost is forming.

 

Bobby

[Ariel]

Hi bobby thanks for the answers!

I think the ambient temperature is not the problem. At the moment that the picture was taken there was about 8-9 °C.