- Myth of Petroleum Products Flash Point - Non Additive property Part 1 of X

- Myth of Petroleum Products Flash Point  - Non Additive property  Part 1 of X

On my last post - Flash Point Blending Calculation formula (http://bit.ly/2kd9FFz)  - received many emails  appreciating the post, at the same time giving notion of lack of basic understanding that too of the practicing petroleum chemists, having some simple facts wrongly learned and needs to be corrected.   That is the reason for starting series of posts under heading - Myth of Petroleum products Flash Point. Let us start with simplest myth.

Myth no, 1:  Flash Point is an additive property.

Fact no. 1:   Flash Point is not an additive property.                     

Some persons believe that Flash Point of products is an additive property.  An additive property means when added together they will result into an arithmetic mean of proportionate to the individual products proprietaries.   Simple Ex. is  If you add substance 1  having some property having value 30 and other having same value 50,  in equal proportion, then resultant will be having value (30+50)/2 ie 40.   Petroleum products properties like Density,  Sulphur Content, Aromatic,  Olefin, Naphthen, Benzene, etc are  having "Additive Property".

Therefore,  Formula for additive property can be as follow:

DensityR  * 100  =  (V1 * Density1 )  +  (V2 *Density2)

Where  DensityR = resultant DensityR of blend in same units

            V1 =  Volume percentage of first component

            V2 = Volume percentage of  Second component

            Density1 =  Density 0f first product

            Density2 =  Density 0f  second product
                               All Volume and density in same unit for comparison purpose)

Formula for non-additive property like Flash Point can be as follow:  

Try to notice difference when compared to above formula.  In above ex. if product one having flash point 30 deg C is mixed in equal proportion, then resultant blend flash point will be 36 deg C and not 40.

From my last post (http://bit.ly/2kd9FFz)       

Ar  * 100  =  (Vx * Ax )  +  (Vy *Ay)

A for Resultant Flash Pt * 100 = ( Volume % of  X * A for  FPx  ) + ( Volume % of Y * A for FPy )

Where  FPr = resultant flash point of blend in centigrade

            Vx =  Volume percentage of X component

            Vy = Volume percentage of  Y component

             Ax =  Constant A from table corresponding to flash point of X

            Ay =  Constant A from table corresponding to flash point of Y

            Ar  = Constant A from table corresponding to flash point of R

It can be noted that, not like density, here no direct flash point value is taken in the formula, but a constant A equivalent to corresponding flash point of product is taken for calculation. This is because Flash Point is a non-Additive Property. (This para is a clue to some readers who have asked how the flash point blending formula is arrived at.)

In summary  Flash Point of petroleum Product is a non additive property and therefore no direct arithmetic proportionate formula works for it.  

Shortly,  another point on subject will be posted, till then enjoy reading my earlier posts at https://rjpatelioc-petroleum.blogspot.in/
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