CBE 417“Unit Operations”

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Instructor: David J. DixonChemical and Biological Engineering Department

South Dakota School of Mines and Technology

Fall 2012

Overview

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• Introduction• UO course overview• Equilibrium Stage separations• What are “Unit Operations”

Overview

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• Introduction• Fulbright experience• ACHEMA June 2012

Overview

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• Introduction• UO course overview• Equilibrium Stage separations• What are “Unit Operations”

Course Overview

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Course Overview

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http://webpages.sdsmt.edu/~ddixon/

Overview

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• Introduction• UO course overview• Equilibrium Stage separations• What are “Unit Operations”Why are separations important in an industrial facility?Feedstocks are generally mixtures that are not particularly useful…so industrial facility (plant) is used to “add value” to the raw materials:Example: (average USA prices on 28 Aug 2012)

Crude oil ~$96/bbl (0.60 $/liter; 0.48 euro/liter)gasoline ~$3.78/gal (1.00 $/liter; 0.80 euro/liter)

Example: (average USA prices on 5 April 2010) Crude oil ~$86/bbl (0.54 $/liter; 0.40 euro/liter)gasoline ~$3.25/gal (0.86 $/liter; 0.64 euro/liter)

Typical Refinery Products

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• Seader & Henley (2006)

Industrial Chemical Facility

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Typical chemical facility might have 40 – 90% of costs invested in separations.

Recovery/Purification Cost vs Concentration

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• Seader & Henley (2006)

Equilibrium Stage Separations

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We could also consider some examples that are non-equilibrium systems; such as membrane and adsorption processes.

Technological Maturity

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• Seader & Henley (2006)

Separations as Unit Operations

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• Seader & Henley (2006; 2011)

Figure 1.15 and Table 1.13

Unit Operation

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What is a “Unit Operation”?• while the chemicals being separated might be different, the

specific technique used has generally the same design methods

• i.e. a distillation column separating ethanol from water is designed in the same general manner as a distillation column separating toluene from xylene.

• Examples of techniques generally called unit operations include:• Distillation• Absorption• Liquid-liquid extraction• Heat exchanger• Etc…

Choosing a Unit Operation

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How does one choose a UO? i.e. ethanol from water separation

• Distillation• Adsorption• Crystallization• L-L extraction• Pervaporation• Absorption

• Seader & Henley (2006)

Separations as Unit Operations

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• Seader & Henley (2006)

19• Seader & Henley (2006)

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• Seader & Henley (2006)

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• Seader & Henley (2006)

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• Seader & Henley (2006)

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• Seader & Henley (2006)

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• Seader & Henley (2006)

Today’s Process Engineering

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Today, most of major unit operations are built into a process simulator and used extensively within the industry. For example:- Simulators: AspenPlus, Fluent, Comsol, ChemSep, others.

Overview

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• Introduction• UO course overview• Equilibrium Stage separations• What are “Unit Operations”

Questions?

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