This approach is sometimes called the Ponchon-Savarit Method. Working on the Hx diagram is more general than a McCabe-Thiele construction, because it. Ponchon – Savarit Method Presentation by. Prof. K. V. Rao Programme Director Department of Petroleum Engineering & Petrochemical Engineering. Lever Arm. Modified versions of the Ponchon-Savarit and McCabe-Thiele methods are presented which incorporate a correct analysis of the feed region in the case of partly.
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Plot the feed and product points. Construct an operating line through both the L 1 point and the D’ point.
This can be used to determine the minimum number of stages. Consequently, there are ponfhon ideal stages required for this separation — with a partial reboiler, that means 4 ideal trays.
Ponchon-Savarit Graphical Equilibrium Stage Method – Wolfram Demonstrations Project
A feed containing 40 mole percent n- hexane and 60 percent n- octane is fed to a distillation column. The tie lines are shown in purple.
On an Hx diagram, there isn’t an equilibrium curve — it has sqvarit to a region, and each point from the xy equilibrium curve is represented by a tie line. Your first stage is drawn correctly. Its intersection with the saturated vapor curve will be the point V 2. In the McCabe-Thiele procedure, operating curves were constructed to represent the component balances for the column and to relate the liquid composition on a stage to the composition of the entering vapor.
These in turn are used with the reflux ratio to get h Dp. Rearranging the enthalpy balance gives: Your name or email address: Download free CDF Player. Maylis pnochon, Apr 21, Yes, my password is: Apr 19, 3. The H- and h- enthalpy versus composition for both the liquid and gas phases are represented by the red and blue curves, respectively.
Some equations in this document are being displayed using MINSEa browser independent approach to displaying equations on the web. Swvarit the tie line that passes through the V 1 point back to savariit saturated liquid curve.
This has been used before if you have used lever arm principles. If the dew point and bubble point lines are more or less straight and roughly parallel, it indicates that the savsrit heat of vaporization is basically constant with respect to composition. If the ponchob are saturated liquid, as is the case for total condensers without subcooling and for partial reboilers, these points will lie on the bubble point curve on the Hx diagram.
The reflux is a saturated liquid and feed enters the column at the optimum stage.
Apr 21, 7. Join Physics Forums Today! This approach is sometimes called the Ponchon-Savarit Method.
Ponchon Savarit Method
Assume that a total condenser is used. Everyone who loves mefhod is here! These were then paired with the equilibrium curve, which savarlt the composition of liquid on a stage to the vapor leaving the stage. So, you will probably want to pick one duty and then construct the line through the feed point to determine the other duty.
If tie lines are not available, they may be constructed using the xy diagram. Once the overall enthalpy line is crossed, construction continues, but operating lines are now drawn between the L i point and the B’ point instead of the D’ point. At total reflux, operating lines are vertical infinite slope.
The “pinch point” also expands, resulting in a single line where the operating and tie lines overlap. This graphical method uses both material and energy balances to determine the number of theoretical stages required to achieve a specific separation.
This is the prerequisite for assuming equimolar overflow, and so the energy balances may be neglected. This will run a special program that should cause them to be formatted for viewing by your browser. Distillation calculations can be performed graphically on an enthalpy-concentration Hx diagram.
The operating lines are developed from enthalpy balances on the rectifying and stripping sections just as in the McCabe-Thiele approach operating equations were developed from the equivalent component balances.
Apr 19, 2. I’m not really sure, but with the way I’m understanding it I think you would really have to have the equilibrium data as well, I think having an enthalpy-concentration data set would just improve your accuracy. Points for the feed and product can be located on the Hx diagram; for our purposes we’ll call them the F, D, and Metod points. For an adiabatic process, the feed and products will be colinear on an Hx diagram.
The very shape of the Hx diagram provides a clue as to the importance of the energy balances. MaylisApr 19, The friendliest, high quality science and math community on the planet! ChestermillerLonchon 19, A calculation often begins by using the overhead product composition and temperature to obtain h D and H y1.
Al-Baghli, and Brian G. Equilibrium data is collected. Apr 19, 1. Apr 22, 8. Related Topics Chemical Engineering Chemistry.
In that diagram the light-blue lines are the stages. The coordinates are their composition and enthalpy. Then the overall enthalpy line is drawn from h Dp through the feed point, and ponchoh intersection with x B gives h Bp.