RVP of Naphtha and LPG

Homework?

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RVP Naphtha has gone up because there are more volatile components in the Naphtha

LPG RVP does not change because there is no change to the volatile component.

So the split for LPG / Naphtha is at C4.

Naphtha is usually limited on RVP but you want as much C4 in Naphtha as gasoline is more valuable than LPG. Similarly you want almost zero C5 in LPG as this is a quality spec. So the column performance is designed to allow operator to split C4 between the two.

As the lightest component in naphtha C4 has an outsize impact on RVP even if its only present in very small fractions. So going from say 5% -> 6% would be seen on RVP.

However for LPG RVP is determined by its lightest component ie C3.

Allowing more C4 into Naphtha would increase RVP (and mass flow) of naptha but would not impact the RVP (and reduce mass flow) of LPG.

Solution change cut point on C4

Either increase reboiler duty, reduce condenser duty change reflux etc

The solution you can figure out for yourself

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