GASOLINE OCTANE BLENDING

The research (RON) and motor (MON) octane numbers of a gasoline blend can be estimated using the following equations: ^[1]

• where

• R=research octane numbers of blend;

• R ₀=research octane number of each component;

• R ₁=volume average of octane number;

• R ₂=volume average of product of R ₀ and J;

• J _X=volume average of sensitivity;

• O ₁=volume average of squared olefin content;

• O ₂=square of volume average olefin content;

• A ₁=volume average of squared aromatic content;

• A ₂=square of volume average aromatic content.

and

where

• M=motor octane of the blend;

• M ₀=motor octane of each component;

• M ₁=volume average motor octane;

• M ₂=volume average of product of M ₀ and J.

These equations represent straight-line blending with three correction terms added to account for the blending deviations normally experienced with gasoline blends. The first term (sensitivity function) is a correction for the blending deviation arising because octane numbers are determined at compression ratio different from those at which the blends are rated. The second (function of olefin content) and third terms (function of aromatic content) are corrections that reflect the influence of chemical interaction of the components in the blend.

The coefficients to be used in octane blending follow. The RON equation coefficients are

• C ₁=0.04307

• C ₂=0.00061

• C ₃= ?0.00046

The MON equation coefficients are

• D ₁=0.04450

• D ₂=0.00081

• D ₃= ?0.00645

These...