The octane vapor pressure at the bottom of the alkylation butane removal column is above 70; the initial boiling point is 34–35; the density is around 0.88 to 0.687. I hope experts can provide some guidance
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The isooctane vapor pressure at the bottom of the alkylation butane removal column is above 70; the initial boiling point is 34–35; the density is around 0.88–0.687
Densities of 0.88 and 0.687? The density of isooctane remains relatively stable, around 0.69–0.7. A high vapor pressure suggests that it may contain some n-butane; trying to remove the n-butane at lower temperatures could help. A density of 0.687 also indicates an excess of light components.
In our plant, the overhead stream from the n-butane separation tower contains about 17% isobutane, and the feed to the isobutane separation tower has a large volume
It means that with isobutane present, the vapor pressure can be kept stable at 0.689, right?
The prerequisite for large production volumes is that product quality must be satisfactory; it’s not about blindly pursuing high production levels. Isn’t it a waste to treat all butane with 17% isobutane as n-butane?
An additional separation tower is needed to separate the liquefied gas components from it; the existing ones can only be handled by adjusting operations and reducing the volume
There’s no other choice; if isobutane cannot be processed, it has to be removed. But this doesn’t affect the quality of octane, so isobutane has to be discarded, and isobutane needs to be replenished on a daily basis
It’s indeed good; only minor adjustments are needed
As an important component used as raw material in alkylation units, isobutane costs far more than household liquefied gas, which represents some waste
Here, due to our production volume, we still need to purchase isobutane as a supplement, and the amount of olefins in the raw materials available is relatively high
Therefore, the isobutane component should be valued even more. It is recommended to investigate the reasons for the overload in the isobutane tower and butane tower from both design and operational perspectives, in order to resolve the issue at its root