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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Ponchon Savarit Method
This approach is sometimes called the Ponchon-Savarit Method. Assume that a total condenser is used. A reflux ratio of 1.
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.
Construction continues until L 5 which is almost directly on top of x B.
Ponchon Savarit Method | Physics Forums
The value of is determined by the program and the ratio of reflux to distillate flow rates at the top stage is chosen such that. I was unaware that it was supposed to be from the vapor curve that I do the next line.
My understanding is that the McCabe Thiele method assumes that the liquid and vapor molar flow rates ponchln constant in each section of the column. Do you already have an account? Thus, it is useful to redefine our distillation system to be adiabatic, by bringing methid condenser and reboiler inside the system boundary.
Your second stage and onwards that 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. After this modification, the system is adiabatic, so a line can be drawn through the feed point, F, and the points x Dh Dp and x Bh Bp. Thanks for showing your work step by step in the images.
RMP Lecture Notes
The optimum feed tray is number 3. A calculation often begins by using the overhead product composition and temperature to obtain h D and H y1. 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 21, 6.
The drawing itself is incorrect Find the number of theoretical stages savariit the optimum feed stage. Apr 20, 4. The operating lines for the stripping metbod rectifying sections are shown in cyan and green, respectively. Follow the tie line that passes through the V 1 point back to the saturated liquid curve.
At total reflux, operating lines are vertical infinite slope. This is the prerequisite for assuming equimolar overflow, and so the energy balances may be neglected.
Its intersection with the saturated vapor curve will be the point V 2. This will run a special program that should cause them to be formatted for viewing by your browser. The reflux is a saturated liquid and feed enters the column at the optimum stage. Points for the feed and product can be located on the Hx diagram; for our purposes we’ll call them the F, D, and B points.
This has been used before if you have used lever arm principles. On an Hx diagram, there isn’t an equilibrium curve — it has expanded to a region, and each point from the xy equilibrium curve is represented by a tie line.
If the saturation curves show significant changes in curvature or separation, it suggests that to assume equimolar overflow will introduce error.
The Ponchon Savarit method does not make this simplifying assumption, so it is more accurate. The friendliest, high quality science and math community on the planet! Eitherway you could actually compute for the number of stages using M-T while incorporating the enthalpy balances I think you know that as wellbut personally I find P-S method faster than M-T incorporating such balances because at least with P-S you just have to continually draw straight lines without having to worry about recomputing the operating and stripping lines every single time, lol.