what is the difference between LNG and LPG consider to its C structure?

Answer 1

Liquefied natural gas consist mainly of methane with a bit of ethane.Typical compositions of natural gas are in the range of:
- methane (CH₄): 70-90 wt.%
- ethane (C₂H₆): 5-15 wt.%
- propane (C₃H₈) and butane (C₄H₁₀): less than 5 wt.%
- other components like CO₂ H₂S H₂O)

Liquified petroleum gas is a byproduct of petroleum refining.
It consists mainly of propane and/or butane.
The composition varies with the refining process. Common mixtures consist of about 60 wt.% propane to 40wt% butane.
Furthermore LPG contains small amounts of propylene (C₃H₆) and butylene (C₄H₈)).

The different compostion is the reason for the major diffrence
in production and handling of LNG and LPG.
The critical temperature of the components sets the upper for liquifaction. The critical temperatures are
-83.6 for methane and +97° for propane (152°C for butane).

That's why petroleum gas can be liquefied by pressurising at ambient temperature level, while natural gas is liquified by cooling.
Moreover LNG is a pretty cold liquid, which requires efficient isolation or cooling in storage and transportation.

Answer 2

Liquefied Natural Gas at -163°C, is mainly Methane (CH4) and Ethane (C2H6).
The liquefaction process I worked on, is a 'Cascade' System of Refrigeration using a 'Multi-component Refrigerant'... (Methane, Ethane, Propane, Butane and Nitrogen...The N2 is added because Methane gas cannot be liquefied by Methane).

Liquefied Petroleum Gas can be pure Butane (C4H10), or pure Propane (C3H8) or a mixture of both.
Due to their different boiling points, the type used depends on the atmospheric conditions of the area in which it's to be used.
Butane only...is used in hot areas.
Propane only...is used in cold areas and the mixture in temperate areas.

Answer 3

All contain C.