Gasoline Blending Plus

Predicting End Point

    End Point is not included in BLENDIS because the interaction model does not fit End Point. Of course the highest end point component essentially controls the End Point of the blend.  However, there are significant differences in the shapes of the End point vs Percent Composition Curve depending upon the difference between 90% and  End Point of the high end point component.  Surprisingly, in certain cases the End Point of a blend of two components can be higher than the End Points of either one.  This is based on a Texaco study reported in 1954.  (Reference 7)

    When a refinery blend has too high an end point, it is difficult to make a correction.  We speculate that a small amount of a narrow boiling component perhaps 20°F below the target end point might work.  The assumption is that such a component would carry over some of the highest boiling hydrocarbons.  If so, this would decrease the distillation rate at the end of the distillation and thereby lower the End Point, by decreasing the heat flow to the thermometer.

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