4 replies to this topic

[Tolinorton]

Hello,

 

Could somebody explain what does this sentence mean:

 

B.4.2. Add the partial motor octane numbers for all of the components determined and round the sum down to the nearest 0,1. (see page 10 on attached PDF file)

 

I'm trying to calculate motor octane number according to EN 589 (Annex for the LPG composition (see attached excel file).

 

 

Attached Files

•  EN 589 Annex B.pdf   20.28KB   9 downloads
•  LPG composition.xlsx   10.13KB   8 downloads

[PingPong]

As it states: Partial octane number = M x C

 

So for example: for a mixture consisting of 40 mol% Propane and 60 % n-Butane the MON of the mixture is:

 

MON = 95.4 * 0.40 + 89.0 * 0.60 = 91.56 = 91.5

[Tolinorton]

Dear PingPong,

 

Thank you for the answer but as you may have seen the composition of LPG is made up not only from Propan and n-Butane, so I don't know Motor octane factor (M) for ethane, ethane, cis-Butene, trans-Butene. and what is more important I really can't understand what does the value of 0,1 mean.

 

For this composition of LPG the MON have to be 95,2 (please see attached Analysis Report).

 

Please is there any book which explains Motor octane factor (M) for every breakdown of Cs.

 

Best regards

Attached Files

•  Analysis Report of LPG.pdf   529.78KB   5 downloads

Edited by Tolinorton, 01 September 2014 - 09:16 AM.

[PingPong]

Look again at Table B.1 in EN589

 

For Ethane (which is C2) take the same value as given for Propane in that table.

For all Butenes (including your cis-Butene and trans-Butene) take the indicated value given for Butenes in that table.

 

" ..... round the sum down to the nearest 0,1 " means that you round the calculated value down to show only one decimal.

To put it simpler: report only the first decimal of the calculated value and remove all other decimals.

[P.K.Rao]

Please refer to the book "THE CHEMICAL TECHNOLOGY OF PETROLEM". Authors: Willam A Gruse and Donald B Stevens. It gives Octane numbers of all hdrocarbons of MS range. It also gives other properties..