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HHV of natural gas components
- Thread starter cmlpetro
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I get those values either from RefProp (a $100 NIST program that is pretty amazing) or from the GPSA Engineering Data Book. Both have SI versions. NIST has a free calculator that is often referenced at eng-tips.com, but it is much more limited than RefProp.
The thing to keep in mind is that STP is in no way "standard". It is a contractual item for gas sales and the contract is a likely to say 0 C as 15 C and the 101.325 kPa often becomes 100 kPa or 1 bar(a), or some other number that the contract negotiators pull from the air. The RefProp program will handle any of these, the GPSA book uses a single value (I don't use the SI version so I don't know what their "Standard" is).
David Simpson, PE
MuleShoe Engineering
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
Remember, being ignorant isn't your fault; staying ignorant is.
The thing to keep in mind is that STP is in no way "standard". It is a contractual item for gas sales and the contract is a likely to say 0 C as 15 C and the 101.325 kPa often becomes 100 kPa or 1 bar(a), or some other number that the contract negotiators pull from the air. The RefProp program will handle any of these, the GPSA book uses a single value (I don't use the SI version so I don't know what their "Standard" is).
David Simpson, PE
MuleShoe Engineering
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
Remember, being ignorant isn't your fault; staying ignorant is.
if you have the energy values but in different units you can convert with PV=ZRT , in your case the procedure should be
Value * (101.325 KPA) / (14.68 PSI * 6.894) * ((60°F - 32) / (1.8) + 273.15) / (15 C + 273.15)
hoping there are no errors, in the first part you convert from PSI to KPA, in the second part from F to K (you need to use the absolute temperature), taking in account that the mass (quantity of substance) contained in the "normal" volume is directly proportional to the reference pressure and indirectly proportional to the reference temperature
as already mentioned there are many software utilities which do these calc's, if you do a search with Google you'll find lots of free programs, I use Prode Properties but I suppose that any other tool can do the work.
Value * (101.325 KPA) / (14.68 PSI * 6.894) * ((60°F - 32) / (1.8) + 273.15) / (15 C + 273.15)
hoping there are no errors, in the first part you convert from PSI to KPA, in the second part from F to K (you need to use the absolute temperature), taking in account that the mass (quantity of substance) contained in the "normal" volume is directly proportional to the reference pressure and indirectly proportional to the reference temperature
as already mentioned there are many software utilities which do these calc's, if you do a search with Google you'll find lots of free programs, I use Prode Properties but I suppose that any other tool can do the work.
The data is available from the GPSA on their website. They are the World standard keeper for HHV.
you are looking for GPA 2145-09, just released about 3 months ago. If you need EXACT content for real gases, then you need to use GPA 2172. REFPROP does not perform the detailed calculations that would be required for custody transfer.
you are looking for GPA 2145-09, just released about 3 months ago. If you need EXACT content for real gases, then you need to use GPA 2172. REFPROP does not perform the detailed calculations that would be required for custody transfer.
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