Emergency flare line!

[Veemax]

Can someone please tell me the effects of the following scenario? A 36 inch steel pipe approximately 1 km long, used as an emergency flare line- containing a mixture of gas vapour and steam. Line temperature of 95 degrees centigrade. If a quantity of cold liquid butane was to be injected into the line- say 5 to 10 cubic meters- what would be the result? Would the butane boil off causing a pressure increase or would it cause a vacuum- possibly collapsing the pipework?

 

[roker]

Veemax,

please clarify:
1. is the butaneinjected during the emergency relief?
2.how the line is kept at 95 C?
3. the flare is usually at low pressure ~0.4 + backpressure so the butane will probably evaporate/
4. is it 5-10 m3 or m3/hr?
5. usually steam is released to the atmosphere or the staem is part of the gas stream.
6. for vacuum a reduction in volume should happened what is the scenario for it?

regards,
roker

 

[Veemax]

1 Yes- butane injected as part of emergency relief- about -2 degrees centigrade.

2 Line being steamed out from process units- 95 degrees centigrade.

3 Yes- normal line back pressure about 0.5 bar.

4 Total quantity about 5 cubic meters- injected over- possibly 2 minutes.

5 No- normally steam is injected at the tip- but all steam controls off- closed!

6 Will this quantity of cold butane being “dumped” into the hot flare line have a cooling effect- causing a possible partial vacuum?

 

[roker]

1. WHAT ARE THE OTHER FLOWS AND CONDITIONS WHEN THE BUTANE IS INJECTED.
2. DO A MASS AND HEAT BALANCE TO SEE THE TEMP AND PRESSURE OF THE MIXTURE.
3. HOW THE PIPE IS KEPT AT 95 C ALL THE TIME? THERE IS NO HEAT LOSS TO THE OUTSIDE AIR?
4. WITHOUT DATA AND A FLOW DIAGRAM IT SEEMS THE BUTANE WILL EVAPORATE.
5. THE FLARE LINE IS NOT A CLOSE SYSTEM SO HOW YOU SEE VACUUM IS KEPT?
6 IF YOU COULD SEND A SKETCH WITH FLOWS, TEMP AND PRESSURE IT WILL BE HELPFUL.

ROKER