3 replies to this topic

[fateton]

Sorry for the audacity.

I'm starting to work with Prode, and I can not find a reliable source of information.

I am not a chemist but mechanical engineer, I want to have an application that gives me certain values to introduce the composition of the natural gas, such as dew point, higher calorific power, k, etc, to evaluate the equipment to be installed in my regulation and measurement station .

I have several doubts and I do not know if you could help me, answering or advising me some manual.

* The function that give me Low Calorific value is strHC()but what is hight calorific valur to?
* When I have a composition , in any case wáter, sulplur ,etc is given as mg/m3 out of the 100% of mole compose by hydrocarbons ( as example 100% molar fraction Ch4 + 1 mg/m3 of sulphur , how can i deal this stream as mixed of these componts?

[serra]

I use Prode Properties from Excel and with my applications,

the operating manual provides a detailed descriptions of the methods available in the library (and exported to Excel and other applications),

 

http://www.prode.com/docs/pppman.pdf

 

see page 68

 

=StrHC(stream)

given a stream returns the calculated net heat of combustion (gas phase)

 

so it is the net heating value (NOT the gross heating value)

the values for many substances are stored in Prode Properties database and you can inspect for Prode Editor, Chemicals->data

 

 

 

for example for Methane the stored value is 344932 Btu/lbm (about the same reported by NIST and other sources)

 

about compositions, to define a stream you can enter individual component's values as mole fractions or mass fractions, you can convert volume fractions to mole fractions (or mass fractions) and then enter values

 

 

 

Attached Files

•  ProdePropertiesEditor.jpg   112.4KB   0 downloads

[fateton]

Thanks for your answer Serra.

But this is my problem how I can calculated the gross heating value in prode.

Attached you can find the compositions of my natural gas, you have tree column, one is the guarantee value and the other the maximum and minimum composition of this gas.

For the guarantee value I calculate the NHV= 48,6476 MJ/kg that match with the value indicated in compositions, but and the Gross value?

In the other hand in the columns "max" you have, per example, Total sulphur S2 as mg/m3 and not as mol % , how I can introduce this in the stream of natural gas.

I modified the excel file that include prode example to calculate this values I attaché the files


Sorry but I don get introduced image and tables in this text.

Thanks in advance

Attached Files

•  compositions.png   23.72KB   2 downloads
•  NHV.pdf   122.43KB   11 downloads
•  Libro1 (Autoguardado) (Recuperado).xlsm   368.28KB   13 downloads

[serra]

normally I use net heat of combustion and Excel macro =StrHC in Prode Properties returns those values,

however a simple rule of thumb for natural gas  is HHV = LHV x 1.11

there are more complex relations if you need additional accuracy

see for example 7.2 net calorific value in ISO 6976 2016

which shows the relation (net vs gross) based on number of hydrogen atoms and latent heat of water,

this forum includes several posts discussing the matter,

 

you can convert from volumes to moles and then enter those values in Prode,

conversion is simple once you know the molar volume of a substance (which you may find in literature or estimate),

but you may also decide to do not include small fractions with little or no influence on final results...

Edited by serra, 04 April 2017 - 04:53 AM.