Flash Separations: Interactive Simulations
These simulations were prepared using Mathematica. Download the free Wolfram player, and then download the simulation CDF file (link given below or click on figure to download). Screencasts below explain how to use these simulations.
This simulation shows an adiabatic flash drum with a liquid feed stream containing a mixture of methanol and water. The feed mole fraction of methanol, the temperature, and the flash drum pressure can be modified with sliders. A bar graph shows the moles of water (blue) and methanol (green). Simultaneous mass and energy balances as well as Raoult’s Law are used to determine the outlet temperature of the flash drum.
Try to answer these questions before determining the answer with the simulation. We suggest that you write down the reasons for your answers.
- As temperature increases, how does V/F change, and how do the exit mole fractions change?
- As pressure increases, how does V/F change, and how do the exit mole fractions change?
The x-y diagram for vapor-liquid equilibrium is shown for a methanol/water stream fed to a flash drum. The corresponding T-x-y diagram shows how the points on the x-y diagram are obtained; each point corresponds to a different temperature. Use buttons to view the x-y and T-x-y diagrams separately or to view both simultaneously. The vapor/liquid ratio leaving the flash drum and the feed composition can be changed with the sliders.
Try to answer these questions before determining the answer with the simulation. We suggest that you write down the reasons for your answers.
- As the L/V ratio increases, how does the effluent temperature of the flash drum change?
- When the feed mole fraction of methanol increases, what changes in the exit streams?
