natural gas processing
natural gas processing
(OP)
Hello,
I have been reading about natural gas processing and I am really confused about Hydrocarbon and water dew point. I clearly understand what they mean but these are my issues:
1) When we pass the gas say into a glycol unit to remove water content and lets say the water dew point is -15 C, are we basically cooling the gas to -15 C?
2) Similarly when gas comes out of separation unit for Hydrocarbons removal by cooling is the gas temperature equals Hydro carbon dew point temperature?
I have been reading about natural gas processing and I am really confused about Hydrocarbon and water dew point. I clearly understand what they mean but these are my issues:
1) When we pass the gas say into a glycol unit to remove water content and lets say the water dew point is -15 C, are we basically cooling the gas to -15 C?
2) Similarly when gas comes out of separation unit for Hydrocarbons removal by cooling is the gas temperature equals Hydro carbon dew point temperature?





RE: natural gas processing
Same with hydrocarbon dew point, you have done something to the stream to remove the things that would condense (at expected pressures) at temperatures above the required dew point.
David
RE: natural gas processing
2.) If the process operates at a perfect equilibrium, the dewpoint of the gas leaving the unit has a hydrocarbon dewpoint that matches the conditions in the low temp separator. Most commercial units have a dewpoint slightly higher due to minor amounts of hydrocarbon carryover.
Get yourself a copy of the GPSA data book - its an excellent reference and you can work through these issues. As well, refer to publications by John Campbell for some good stuff.
RE: natural gas processing
RE: natural gas processing
The phase invelope may mean that at your operating pressure - the HC dewpoint may not be the highest. This means that condensation could occur if the pressure changed somewhere but the temperature remained constant.
Also, retrograde condensation may occur if you are operating your LT process near the "top" of the phase envelope. The ctrical point is often somewhere a little down the boiling point curve. This means that the HC dewpoint could in fact increase even if you lowered your operating temp.
Bets regards
Morten
RE: natural gas processing
These type units separate methane from C2 and higher compounds except permit just enough stuff to increase the mostly methane gas BTU within the requirements. The C2 and related stuff can be mixed or separated and sold for other products.