- Kin. Viscosity Calculator - blend of Petroleum Products

Following article is mainly for gasoil,  how to predict blended product Kin. Viscosity.

Kin. Viscosity  like Flash point is not an additive property.

How to predict Kin. Viscosity of resultant product after blending two stocks ?  or  how to get volume required of products to get desired  blended product Kin. Viscosity ?

Many times Viscosity improvement is desired by blending higher Viscosity petroleum product to lower Viscosity Product at Petroleum storage depots.

Following table and formula can be used to predict the desirable variable figure of  kin. Viscosity or volume of product.   In the table below against Kin. Viscosity (cSt)  viscosity blending number "A" is listed in next column.

Formula :

Ar  * 100  =  (V1 * A1 )  +  (V2 *A2)

A for Resultant KV * 100
= ( Volume % of  Stock1 * A for  Stock1  ) + ( Volume % of Stock2  * A for Stock2 )

Kin. Viscosity is in cSt and it is at any given temperature.

Where  Viscosity blending number A can be taken from table against Kin. Viscosity.

Kin. Visc	A	Kin. Visc	A	Kin. Visc	A
Cst		Cst		Cst
1.4	119.6	3.6	66.6	5.8	49.5
1.6	110.1	3.8	64.4	6	48.5
1.8	102.3	4	62.4	6.2	47.5
2	95.8	4.2	60.5	6.4	46.6
2.2	90.3	4.4	58.8	6.6	45.7
2.4	85.6	4.6	57.2	6.8	44.9
2.6	81.5	4.8	55.7	7	44.1
2.8	77.8	5	54.3	7.2	43.3
3	74.5	5.2	53.0	7.4	42.6
3.2	71.6	5.4	51.8	7.6	41.9
3.4	69.0	5.6	50.6	7.8	41.2

  Above table is based on equation

Viscosity Blending Index = 147.3  X  (Kin. Visc)^(-0.62)
           

The above  is clear from the following examples:

Ex 1:     KV of Blend 

                Stock1,  KV=  1.8 cSt,   vol=50 %,   From table Blending number A for 1.8 = 102.3

                 Stock2,  KV=  6.4 cSt,   vol=50 %,   From table Blending number A for 4.8 = 55.7 ,   

Then  from equation   Ar* 100 = (50 * 102.3)  + (50 * 55.7)

              Solving         Ar  = 79

      From the table,  nearest  Resultant KV is  2.7 at Blending number Ar of  79  

Ex 2:       Stock1,  KV=  2.8 cSt,   vol=20 %,   From table Blending number A for 2.8 = 77.8

                 Stock2,  KV=  6.4 cSt,   vol=80 %,   From table Blending number A for 6.4 = 46.6 ,   

Then  from equation   Ar* 100 = (20 * 77.8)  + (80 * 46.6)

              Solving         Ar  = 52.8

   From the table,  nearest  Resultant KV is  5.28 at Blending number Ar of  52.8  

                                                                                                                                                                                                                                                                                                                                                                                                     

Notes :  Above calculations predict nearly accurate Kin. Viscosity of blended product, however, usual precautions are must for margin in KV to take care non-homogeneity of mixture and layering in petroleum product tank.

For Excel sheet of above as calculator  follow link
https://rjpatelioc-petroleum.blogspot.in/2017/04/kin-viscosity-gasoil-excel-calculator.html

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