With the help of McCabe-Thiele diagram we can also determine the minimum reflux ratio. It is again pretty simple and direct. One only has to know how to use the diagram.
First of all, we need to mark all those points that we know such as distillate-,bottom- and feed composition. This time feed composition and feed phase are important and cannot be neglected.
Secondly draw a feed line from the feed composition point marked in the diagram. In case of having a saturated-liquid feed, a vertical line is drawn until it touches the equilibrium curve.
Then draw an operating line from the distillate composition that passes through the intersection point between feed line and equilibrium curve.
After that extrapolate that operating line until it intersects with y-axis at point a.
Knowing the value of a, the minimum reflux ratio can be calculated. We have seen that the y-intercept of an operating line for a rectifying section is equal to xd/(v+1). Since xd is normally known or given, v or v(min) can easily be determined.
First of all, we need to mark all those points that we know such as distillate-,bottom- and feed composition. This time feed composition and feed phase are important and cannot be neglected.
Secondly draw a feed line from the feed composition point marked in the diagram. In case of having a saturated-liquid feed, a vertical line is drawn until it touches the equilibrium curve.
Then draw an operating line from the distillate composition that passes through the intersection point between feed line and equilibrium curve.
After that extrapolate that operating line until it intersects with y-axis at point a.
Knowing the value of a, the minimum reflux ratio can be calculated. We have seen that the y-intercept of an operating line for a rectifying section is equal to xd/(v+1). Since xd is normally known or given, v or v(min) can easily be determined.
No comments:
Post a Comment