Falling Drop Experiment A study on liquid- liquid extraction using a single drop Team Leader:Thomas Salerno Group Members:Gregory Rothsching An Du

Presentation Agenda Introduction – What is LLE and single drop extraction? Theory – How do we analyze and model LLE? Equipment and Procedure – What did we use? Results and Discussions – What did we find? Conclusions – How can we use these results? Questions – What parts did I go too fast on?

Introduction What is LLE? – One or more solutes are removed from one liquid phase to another, immiscible phase which has a greater affinity for the solute Why use LLE over distillation? – LLE requires no vaporization – Less expensive, no condenser nor reboiler

Introduction Where is LLE used? – Penicillin manufacture – Petroleum Processing Why is this experiment important? – Many of the predictive equations require experimental measurements – Using single drop allows quick measurements on lab scale instead of designing on a pilot plant scale

Theory - Experimental Initial Measurements – Volume of Drop – Terminal Velocity

Theory - Experimental Mass Transfer Measurements – Mass Transfer Rate – Overall Mass Transfer Coefficient – Equilibrium Distribution Coefficient

Theory - Predictive Terminal Velocity – Force Balance on Falling Drop – Using the definition of terminal velocity – Coefficient of Drag Correlation?

Theory - Predictive Overall Mass Transfer Coefficient – Three mass transfer mechanisms – Create one model to account for all?

Theory - Predictive Outside Mass Transfer Coefficient – Apply regular boundary layer equations Continuity: Momentum: Mass : – Final Result:

Theory - Predictive Inside Mass Transfer Coefficient – Oscillating Drop – Develop probability distribution – Final Result:

Theory - Predictive Overall Mass Transfer Coefficient – Two resistance theory: – Graphically relate driving force – Result:

Equipment and Procedure Week 1: Experimental Measurements

Equipment and Procedure Week 2: Titrations

Results and Discussions Terminal Velocity

Results and Discussions Distribution Coefficient

Results and Discussions Overall Mass Transfer Coefficient – Experimental vs Theory:

Results and Discussions Overall Mass Transfer Coefficient – The Major Factors:

Results and Discussions Overall Mass Transfer Coefficient – Instability Factor: Accounts for non-idealities of the system Constant with diameter and scale-up

Results and Discussions Overall Mass Transfer Coefficient – Experimental vs Predicted with

Results and Discussions Mass Transfer Rate – Two Factors: Surface Area and Mass Transfer Coefficient

Conclusions Mass transfer coefficient decreases with increasing diameter – Toluene Phase is the controlling resistance. Mass transfer rate increases with increasing diameter – The surface area is the controlling factor. Trends were predicted by theory, however, experimental data is needed to get exact numbers – Non-idealities in system: Surface tension, coalescence – Oscillations in drop.

Questions?