2 replies to this topic

[jprocess]

Dear All:
There are 2 terms that often used with de-methaniser columns and these are:
Maximum methane slippage and minimum methane slippage.
I want to ask from experienced engineers in this field that what do these two terms mean?and what are their importance?
Why it is not convenient to use similar terms for other columns?for example maximum/minimum ethane slippage for a de-ethaniser column?
Thanks in advance.
Kindest Regards.

[vinay]

Dear jprocess,

The slippage of any component from Distillation column indicates the amount of that component escaping from the column along with column Top/bottom Product (where it was not desirable)

For example in your case of DeEthaniser column (assuming ethane is taken from column top) , the amount of ethane going from column bottom to the next column (Depropanizer ) would be called Ethane slippage from Deethanizer column & there are upper limits sets uptill which it can be allowed in next colum as more amount of ethane slippage would cause next column to not only operate at higher pressure (which may not be desirable ) but also will contaminate depropanizer top stream with ethane where only propane should have been going.

I hope my explanation has brought more clarity to your issue.

Regards,

Vinay Mathur

[abhi_agrawa]

Jprocess,

Can you give us a few more detials of the process? I am familiar with Crackers, there maximum Methane slippage is the Maximum amout of Methane allowed in Demethanizer bottoms. It is an important parameter as this methane will go the Ethylene product. Therefore allowed Methane slippage is the maximum amount of Methane that can be tolerated in Ethylene product. I am not aware of any minimum Methane slippage though.

Hope this helps,

abhishek