7/30/2019 Product Seperation (Downstream)
1/16
7/30/2019 Product Seperation (Downstream)
2/16
7/30/2019 Product Seperation (Downstream)
3/16
7/30/2019 Product Seperation (Downstream)
4/16
7/30/2019 Product Seperation (Downstream)
5/16
7/30/2019 Product Seperation (Downstream)
6/16
STEAM DISTILLATION
7/30/2019 Product Seperation (Downstream)
7/16
7/30/2019 Product Seperation (Downstream)
8/16
7/30/2019 Product Seperation (Downstream)
9/16
The dielectric constant is a measure of the degree of molar polarization of
a compound. If this value is known it is then possible to predict whether a
compound will be polar or non-polar, with a high value indicating a highly
polar compound
The final choice of solvent will be influenced distribution or partition coefficient
K where
K= Concentration of solute in extract / Concentration of solute in raffinate
The value of K defines the ease of extraction. There is a relatively high K
value, good stability product and good separation of the aqueous and vent
phases, then it may be possible to use a Smgle-stilge extraction system.
A value of 50 indicatles that the extraction should be Straightforward
whereas value of 0.1 shows that the extraction will be and that amultistage process will be necessary.
7/30/2019 Product Seperation (Downstream)
10/16
The co-current system
There are n mixer/separator vessels in line and the raffinate goes from vessel
1 to vessel n.
Fresh solvent is added to each stage, the feed and extracting solvent pass
through the cascade in the same direction. Extract is recovered from each
stage.
Although a relatively large amount of solvent is used, a high degree of
extraction is achieved.
7/30/2019 Product Seperation (Downstream)
11/16
A counter-current system
There. are a number of mixer/separators connected in series. The extracted
raffinate passes from vessel 1 to vessel n while the product-enriched solvent is
flowing from vessel n to vessel 1.
The feed and extracting solvent pass through the cascade in opposite
directions. The most efficient system for solvent utilization is counter-currentoperation, showing a considerable advantage
over batch and co-current systems.
7/30/2019 Product Seperation (Downstream)
12/16
7/30/2019 Product Seperation (Downstream)
13/16
7/30/2019 Product Seperation (Downstream)
14/16
7/30/2019 Product Seperation (Downstream)
15/16
There are, however, a number of significant disadvantages in the utilization of
this technology:
(i) Phase equilibria of the solvent/solute system is complex, making design ofextraction conditions difficult.
(ii) The most popular solvent (carbon dioxide) is non-polar and is therefore
most useful in the extraction of non-polar solutes. Though cosolvents
can be added for the extraction of polar compounds, they will complicate
further downstream processing.
(iii) The use of high pressures leads to capital costs for plant, and operating
costs may also be high.
7/30/2019 Product Seperation (Downstream)
16/16