PPT - Absorption | Mass Transfer - Chemical Engineering PDF Download

 Page 1


ABSORPTION
Page 2


ABSORPTION
What is Absorption?
 Absorption is the transfer of one or more
materials from the gas phase to a liquid
solvent
 It is typically a physical phenomenon and
often involves no change in the chemical
species present in the system
 It is an important mitigation method
Page 3


ABSORPTION
What is Absorption?
 Absorption is the transfer of one or more
materials from the gas phase to a liquid
solvent
 It is typically a physical phenomenon and
often involves no change in the chemical
species present in the system
 It is an important mitigation method
Terminology
 Solute:- It is the material that is transferred from
the gas to the liquid phase
 Liquid desiccants:- Liquid solutions that have the
property of absorbing moisture from air, e.g.,
lithium chloride and triethylene glycol
 Scrubbing:- Another term for absorption
 Salting out:- Liquid desiccants contain significant
amount of water in which the pollutants are
dissolved, and presence of certain chemicals like
lithium chloride can decrease the solubility of
pollutants in water, this phenomenon is known as
salting out.
Page 4


ABSORPTION
What is Absorption?
 Absorption is the transfer of one or more
materials from the gas phase to a liquid
solvent
 It is typically a physical phenomenon and
often involves no change in the chemical
species present in the system
 It is an important mitigation method
Terminology
 Solute:- It is the material that is transferred from
the gas to the liquid phase
 Liquid desiccants:- Liquid solutions that have the
property of absorbing moisture from air, e.g.,
lithium chloride and triethylene glycol
 Scrubbing:- Another term for absorption
 Salting out:- Liquid desiccants contain significant
amount of water in which the pollutants are
dissolved, and presence of certain chemicals like
lithium chloride can decrease the solubility of
pollutants in water, this phenomenon is known as
salting out.
Fundamentals
 Prediction of performance of absorbers and
absorption equipment
àThe first approach makes use of mass
transfer coefficients and depends on the molecular
diffusivities of the solute for the equipment in
which the operation is being carried out
à The second technique is a graphical
solution method
à The third method is described as the
absorption factor or overall approach
Page 5


ABSORPTION
What is Absorption?
 Absorption is the transfer of one or more
materials from the gas phase to a liquid
solvent
 It is typically a physical phenomenon and
often involves no change in the chemical
species present in the system
 It is an important mitigation method
Terminology
 Solute:- It is the material that is transferred from
the gas to the liquid phase
 Liquid desiccants:- Liquid solutions that have the
property of absorbing moisture from air, e.g.,
lithium chloride and triethylene glycol
 Scrubbing:- Another term for absorption
 Salting out:- Liquid desiccants contain significant
amount of water in which the pollutants are
dissolved, and presence of certain chemicals like
lithium chloride can decrease the solubility of
pollutants in water, this phenomenon is known as
salting out.
Fundamentals
 Prediction of performance of absorbers and
absorption equipment
àThe first approach makes use of mass
transfer coefficients and depends on the molecular
diffusivities of the solute for the equipment in
which the operation is being carried out
à The second technique is a graphical
solution method
à The third method is described as the
absorption factor or overall approach
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