Separation Methods: MSA and Stripping

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the typical size range of molecules retained in microfiltration?

0.02 to 10 nm

1 to 20 nm

1 to 20 μm (correct)

0.02 to 10 μm

What is the driving force used in pervaporation?

Electric potential gradient

Pressure gradient (correct)

Concentration gradient

Temperature gradient

What is the typical application of ultrafiltration?

Recovery of caustic from hemicellulose

Hydrogen enrichment

Separation of whey from cheese

Removal of bacteria from drinking water (correct)

What is the characteristic of the separating agent in gas permeation?

Nonporous membrane Signup and view all the answers

What is the purpose of the solid mass separating agent in separation by solid agent?

All of the above Signup and view all the answers

What is the main difference between pervaporation and reverse osmosis?

Type of membrane used Signup and view all the answers

What is the typical application of microfiltration?

Removal of bacteria from drinking water Signup and view all the answers

What is the characteristic of the membrane used in pervaporation?

Nonporous Signup and view all the answers

What is the primary mechanism of separation in microporous membranes?

Differences in rate of diffusion through the pores Signup and view all the answers

What is the main purpose of Reverse Osmosis?

To desalinate seawater Signup and view all the answers

What is the primary function of a nonporous membrane in Osmosis?

To allow solvents to pass through Signup and view all the answers

What is the main characteristic of the membrane used in Dialysis?

Porous Signup and view all the answers

What is the process of extracting sucrose from sugar beets with hot water an example of?

Leaching Signup and view all the answers

What is the driving force behind the separation process in Osmosis?

Concentration gradient Signup and view all the answers

What is the primary role of a separating agent in liquid-liquid extraction?

To selectively dissolve one or a fraction of the components in the feed mixture Signup and view all the answers

Which of the following techniques is an example of solid-liquid extraction?

Leaching Signup and view all the answers

What is the role of heat transfer in azeotropic distillation?

To facilitate the formation of a minimum-boiling azeotropic mixture Signup and view all the answers

Which of the following techniques involves the use of two liquid solvents?

Liquid-liquid extraction with two solvents Signup and view all the answers

What is the purpose of contacting the liquid feed with a stripping agent?

To separate the feed mixture at elevated temperature and ambient pressure Signup and view all the answers

Which of the following techniques is used when distillation is impractical?

Liquid-liquid extraction Signup and view all the answers

What is the role of an entrainer in azeotropic distillation?

To form a minimum-boiling azeotropic mixture with water Signup and view all the answers

Which of the following techniques involves the use of a liquid absorbent as a separating agent?

Separation using a liquid absorbent Signup and view all the answers

Study Notes

Separation by Mass Separating Agent (MSA)

Separating agent: Liquid absorbent (MSA)
Example: Separation of carbon dioxide from combustion products by absorption with aqueous solutions of an ethanolamine

Stripping

A liquid mixture is separated, generally at elevated temperature and ambient pressure, by contacting liquid feed with a stripping agent
Separating agent: Stripping vapor (MSA)
Example: Stream stripping of naphtha, kerosene, and gas oil side cuts from crude distillation unit to remove light ends

Azeotropic Distillation

Formation of minimum-boiling azeotropic mixtures
Separating agent: Liquid entrainer (MSA) and heat transfer (ESA)
Example: Separation of acetic acid from water using n-butyl acetate as entrainer to form azeotrope with water

Liquid-Liquid Extraction

Widely used when distillation is impractical, especially when the mixture to be separated is temperature-sensitive
The solvent selectively dissolves only one or a fraction of the components in the feed mixture
Separating agent: Liquid solvent (MSA)
Example: Recovery of Aromatics

Liquid-Liquid Extraction (Two Solvents)

Each solvent has its own specific selectivity for dissolving the components of the feed mixture
Separating agent: Two liquid solvents (MSA1 and MSA2)
Example: Use of propane and cresylic acid as solvents to separate paraffins from aromatics and naphthenes

Leaching

Referred to as solid-liquid extraction
Widely used in the metallurgical, natural product, and food industries
To promote diffusion of the solute out of the solid and into the liquid solvent
Separating agent: Liquid solvent
Example: Extraction of sucrose from sugar beets with hot water

Separation by Barrier

The use of microporous and nonporous membranes as semipermeable barriers for difficult and highly selective operations
For microporous membranes, separation is effected by differing rates of diffusion through the pores
For nonporous membranes, separation occurs because of differences in both solubility in the membrane and the rate of diffusion through the membrane

Osmosis

Involves transfer, by a concentration gradient, of a solvent through a membrane into a mixture of solute and solvent
The membrane is almost nonpermeable to the solute
Separating agent: Nonporous membrane

Reverse Osmosis

Transport of solvent in the opposite direction and is effected by imposing a pressure, higher than osmotic pressure on the feed side
Separating agent: Nonporous membrane with pressure gradient
Example: Desalination of sea water

Dialysis

Transport, by concentration gradient, of small solute molecules, sometimes called crystalloids, through a porous membrane
Separating agent: Porous membrane with pressure gradient
Example: Recovery of caustic from hemicellulose

Microfiltration

Retention of molecules typically in the size range from 0.02 to 10 μm
Separating agent: Microporous membrane with pressure gradient
Example: Removal of bacteria from drinking water

Ultrafiltration

Retention of molecules typically in the size range from 1 to 20 nm
Separating agent: Microporous membrane with pressure gradient
Example: Separation of whey from cheese

Pervaporation

The species being absorbed by and transported through the nonporous membrane are evaporated
Uses lower pressures than RO
Separating agent: Nonporous membrane with pressure gradient
Example: Separation of azeotropic mixtures

Gas Permeation

Separation of gas mixtures through membranes, using pressure as the driving force
Separating agent: Nonporous membrane with pressure gradient
Example: Hydrogen enrichment

Separation by Solid Agent

Usually in the form of granular material or packing
Acts as an inert support for a thin layer of absorbent or enters directly into the separation operation by selective adsorption of, or chemical reaction with, certain species in the mixture
The active separating agent eventually becomes saturated with solute and must be regenerated or replaced periodically

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Learn about two common separation methods: MSA (Mass Separating Agent) and Stripping. Understand how MSA uses a liquid absorbent to separate mixtures, while Stripping uses a stripping agent at elevated temperatures.