Cracked Naphtha-Light Cycle Oil Gap

[NickVil]

Hi,
I have been checking the historical trend (from 2002 to 2008) about the differences between cracked naphtha final boiling point and light cycle oil (LCO) initial boiling point and I found that always the Naphtha End point is lesser than the LCO IBP.
I want to know if this is normal. If is so, can anyone explain the reason?
I know that we need to check the T5%LCO - T95% Naphtha, but the difference is bigger.

Regards

 

[EmmanuelTop]

The difference in 5/95% boling points of adjacent products is the measure of fractionation efficiency in distillation towers.

There are no cases which are "normal" or "not normal" - it all depends on what fractionation efficiency and separation sharpness your tower has been designed for, and what are the actual parameters versus design parameters.

In general, it's always better to have positive difference, such in your case. It means you're not losing naphtha in LCO and vice versa.

Best regards,

 

[nsuhas]

Hey Nickvil...
It looks like something is not correct.. Its is not possible to have LCO IBP > HVY NAP End point, if your Lab is using same Distillation method to characterise for both.

Check the distillation method your are carrying out on both the products.

Suhas