# Performing Multi-Phase Mass and Energy Balances (Separations)

### Performing Multi - Phase Mass and Energy Balances

Using thermodynamics in mass / energy balance problems means that additional equations are available for solving the required unknowns.

How can VLE calculations be used in mass balance applications?

• Solve multi - component flash distillation problems
• Derive and use the lever - arm rule
• Explain and sketch the basic flash distillation process [W: Ch. 2.1]
• Derive and plot the operating equation for a binary flash distillation on a y - x diagram [W: Ch. 2.4]
• Solve both sequential and simultaneous binary flash distillation problems.
• Explain the difference between (and solve) binary and multi-component flash calculations [W: Ch. 2.5, 2.6]
• Write and solve mass and energy balances for multi - stage distillation
• Explain the connection between column and flash distillation processes [W: Ch. 3.1, 3.2]
• Write the mass and energy balances and equilibrium expressions for any stage in a column [W: Ch. 3.4, 4.1, 4.2]
• Explain what constant molal overflow(CMO) is, and determine if it is valid in a given situation [W: Ch. 4.2]
• Determine the operating equations for CMO systems [W: Ch. 4.3]
• Determine the number of stages required to achieve a separation, using the Lewis method [W: Ch. 4.3]
• Calculate the feed quality and determine its effect on flowrates [W: Ch. 4.4]
• Plot the feed line on a y - x diagram [W: Ch. 4.4]
• Determine the number of stages required to achieve a separation, using the McCabe - Thiele method [W: Ch. 4.5]
• Solve total and minimum reflux problems when CMO is valid [W: Ch. 4.5, 4.8, 4.10]
• Explain why multicomponent distillation is trial - and - error [W: Ch. 5.1]
• Make appropriate assumptions and make external mass balances for multicomponent distillation problems [W: Ch. 5.1]
• Perform gas - liquid(solubility) and liquid - liquid equilibrium mass balances
• Explain what absorption and stripping do and describe a complete gas treatment plant
• Use the McCabe - Thiele method to analyze absorption and stripping systems for both concentrated and dilute systems
• Solve both immiscible and partially miscible extraction problems