User`s guide

2 LTI Models
2-48
Figure 2-3: Distillation Column
Schematica lly, t he dis tillat io n p rocess functions as follo ws:
• Stea m flow s into the reb oil er and vapo rizes the bot tom li quid. This vapo r is
reinjecte d into the co lu mn and mixes with the feed
• Methanol, being more volatile than water, tends to concentrate in the vapor
moving upward. Meanwhile, water t ends to flow downward a nd accumulate
as the bott om l iquid
• The vapor exiting at t he to p of t he co lumn is condensed by a flow o f coo li ng
water. Part of this co ndens ed vapor is extra c ted as the distillat e, and the rest
of th e condensate (th e reflux) is sent back to the column.
• Part of the bo ttom liquid is colle cte d f rom the reboil er a s b ot to m p rodu ct s
(waste).
Feed
Enriched vapor
Cooling water
Condensate
Reflux
Distillate
Vapor
Steam flow
Reboiler
Bottom liq uid
Bottom products