Internal Energy of Natural Gas

[robip]

1. The problem statement, all variables and given/known data
I have liquid natural gas, or LNG, at -165degrees Celsius. I want to know the total energy required to heat the gas up 50ml to 5 degrees Celsius.


2. Relevant equations
Not sure.
Im assuming I need information regarding specific heat etc. Heat of vaporization maybe?

3. The attempt at a solution
Tried to hunt down some more data on LNG but couldn't find it. I do remember a formula from my highschool days a long the lines of Q=MC(T2-T1). Not sure however if that only applies to solids?

[eli64]

total energy = H1 + H2 + H3

H1 = (Cp x mass x (bp - (-165oc))
H2 = (heat of vap x mass)
H3 = (Cp x mass x (5oC - bp)

Yes you will need density, specific heat and Heat of vap of the LNG (and b.p of course) - don't know if it will be good enough to use the methane values though

[robip]

Ok I needed a fair amount of safety, so I used worst case scenarios of Cp being 2.5J/kg.K and Vap being approx 600kJ/kg. The specific gravity was 0.6.

I calculated it to being approx. 30kJ. Does that sound correct?