You're probably a young Chem E who hasn't been exposed to the Hydrocarbon industry - especially fossil fuels.
NGL is an acronym for Natural Gas Liquids - the liquid hydrocarbons normally associated with "Natural" gas, which is composed mainly of methane, ethane, and "heavies" like propane & butanes. Depending on the gas pressure, the heavies will condense and constitute the liquid or "wet" portion of the natural gas. NGLs are much more valuable as raw material for further processing than as fuel for simple combustion.
LNG is an acronym for Liquefied Natural Gas - the gaseous portion of a natural gas (mostly the methane and a little ethane) in the liquefied state (-260 oF) & 1 atm. This is an efficient way to move, transport and handle large, bulk quantities of natural gas instead of trying to store it in the gaseous state at elevated pressures.
I hope this clears up your understanding of the terms.
Montemayer,
Anecdotal
I thought that you would remember that NGL is "Casing Head Gasoline".
I have a friend that is restoring an old Fairbanks Morse single cylinder engine that runs on CHG. He had more trouble getting the fuel than restoring the engine.
Didn't the old pumping engines on wells run on this product?
Unclesyd,
The "Casinghead Gasoline" is more properly called "condensate" or "drip", it is sold by the tank and transported in atmospheric trucks.
NGL is made up of products that are gaseous near atmospheric conditions (Art's Propane and Butane refereneces) and are generally not included in condensate sales. Ethane is really the swing product and every modern gas plant has ethane-rejection strategies that swing the magnitude of the inclusion or rejection of ethane in the natural-gas stream based on value for heat content. Sometimes ethane is more valuable as a feedstock and sometimes it is more valuable as a fuel additive.
Products much heavier than butane will mostly be sold as condensate and are a royal pain within cryo plants.
When the market is good, the so-called cryogenic gas plants also extract as much ethane as practical from the gas while meeting the btu specification in the gas. As previously explained, the term NGL or natural gas liquid pertains to ethane through butane that would evaporate at atmospheric pressure on a warm day. Drip gas contains more of the liquid that is heavier than the lighter fractions.
