Chem Lecture 1

8/12/2019 Chem Lecture 1

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CENG 101

Lecture 1. Chemical Engineering Processes (5 h)

Learning Objectives:

(1) Introduction to Chemical Engineering and Processes

(2) Chemical Engineering Calculation

Units and conversion

Measurements and calculation

Dimension and dimensionless quantities

Data Presentation and analysis

(3) Processes and Process Variables

Mass and volume flow

Chemical compositionTemperature and pressure

Learning Guides:

(1) Lecture handouts

(2) Chapters 1-2 of Textbook: Elementary principles of

chemical processes

CENG 101

Lecture 1. Chemical Engineering Processes (5 h)

Learning Objectives:

(1) Introduction to Chemical Engineering and Processes

(2) Chemical Engineering CalculationUnits and conversion

Measurements and calculation

Dimension and dimensionless quantities

Data Presentation and analysis

(3) Processes and Process Variables

Mass and volume flow

Chemical compositionTemperature and pressure

Learning Guides:

(1) Lecture handouts

(2) Chapters 1-2 of Textbook: Elementary principles of

chemical processes

Chemical Engineering

(1) Chemical Engineering involves taking natural raw materials and

transforming them into useful products:

Crude Oil

Refinery

Phy

sicaltr

ansformatio

ndistillation

Chemical transformation


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Chemical Engineering Processes may involve

(1) Transport of materials

(2) Physical transformation of materials

Distillation

Smelting

(3) Chemically transformation of materials



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(4) Waste reduction, pollution reduction and abatement


Wastewater treatment

Recycling

(5) Understanding of energy generation and transformation


(a) Efficiency of a process

(b) Phase equilibria


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(c) Reaction


(d) Physical properties of materials

Conductivity

Crystal shape and size

Self-assembly structures

Protein folding



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Discovery

Product

Chemical

Engineering

From Research to Product

(1) What is the product ? Who is the customer ?

- Better synthetic rubber for athletic shoes

- Nike company

We do not make a lot of things you use, but

we make it better . 3M

(2) How much will they pay ? How much should it cost ?

- Market analysis, consultation with main target

customer

- Account for the financing the building or refurbishing

of production plant, cost of raw materials and operationcost.

(3) How do we produce it ? (Process)

- Understand the basic chemistry of the reaction

A + B + Energy Product + D + heat

Guide for developing a production process


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(1) Mix the reactant A and B

Process Design and Development

ReactorA + B Product + C

Heat

(a) use giant test tube

(b) batch reactor

(c) tube reactor

(2) Design and build the reactor

- Tubular reactor

Size ?

Material ?

Stainless steel?

Glass-lined for corrosive reaction

Heating ?Electrical heater, heat exchanger or steam jacket



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(3) Reactant A & B

State of Material: Solid, liquid or gas ?


ReactorA + B Product + C

Heat

(3) Reactant A & B

Buy or produce ? $$ ?

Purity ?

Transportation ?

Solid reactant A


Crusher to reduce particle size

and promote reaction

Screw pump to transport reactant A

to the reactor

Extractor to remove

impurities


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(4) Product


Reactor Product + C

Heat

Raw Material B

Separator 2

Raw Material A

Separator 1

Sold the product as is ?

Or purify and get higher price ?

(5) By-product C, unreacted A & B


Reactor

Heat

Raw Material B

Separator 2

Raw Material A

Separator 1

Product 2

Separator 4

Product

Separator 3

Separate and sell ? Or separate and recycle for reuse ?


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(6) Safety and Environment

Automate Process ?

Safety guidelines and precautions ?

Waste reduction and treatment ?

Release guidelines ?

Community action group ? Education ?


http://www.eng.auburn.edu/users/tplacek/courses/2100/HowToSucceed.html


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(1) Fundamental dimensions length, mass and time

Metric unit

MKS: meter (m), kilogram (kg) and second (s)

cgs: centimeter (cm), gram (g) and second (s)

English unit

foot (ft), poundmass (lbm) and second (sec)

Conversions

1 m = 100 cm

= 3.28 ft = 39.37 in

1 kg = 1000 g

= 2.204 lbm

1 s = 1 sec

(2) Derived dimensions based on primitive units

(a) Force

F = mass x acceleration = ma

Metric unit MKS: Newton (N) English unit: poundal (lbf)

cgs: dyne

Conversions

1 N = 1 kg m s-2

= 105 dynes

= 0.2248 lbf

Dimensions and Units in Chemical Engineering

http://www.chemie.fu-berlin.de/chemistry/general/units_en.html

(b) Pressure

P = force/area = F/A

Metric unit MKS: Bar (bar) English unit: atmosphere (atm)

cgs: Pascal (Pa)

Conversions

1 bar = 105 kg m-1 s-2 = 105N m-2

= 105 Pa = 102 kPa

= 106 dyne cm-2

= 0.986 atm = 14.504 psia = 750 torr


http://www.chemie.fu-berlin.de/chemistry/general/units_en.html

1 torr = 1 mm Hg1 atm = pressure exerted by the air at

see level

1 atm = 760 mm Hg

1 atm = 14.7 psia

1 psia = 1 poundal per square inch

absolute


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(c) Temperature

Metric unit: Kelvin (K) English unit: Rankine (R)

Conversions

T (K) = t(C) + 273 = T(R)/1.8

T (R) = t(F) + 460

t(F) = 1.8 t(C) + 32


Zeroth Law of Thermodynamics

(d) Energy

E = force x distance = Fl

Metric unit MKS: Joules (J) English unit: ft-lbf and BTU

cgs: Erg (erg)

Conversions

1 J = 1 kg m-2 s-2 = 1 N m

= 10 cm3 bar

= 107 dyne cm = 107 erg

= 0.239 cal

= 0.7376 ft-lbf

= 9.478 x 10-4 BTU

Types of Energies:

Stored Energies: Internal energy (energy stored in molecules)

Potential energy (configurational energy)

Kinetic energy (motion)

Transient Energies: Work (mechanical work)

Heat


macroscopic


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(1) Kinetic Energy energy stored in moving objects

Ek = 1/2 mu2

Mechanical Energies

(2) Potential Energy energy stored in objects due to their relative

position or configuration.

Gravitational potential energy: Ep = mgz

Elastic potential energy: Ep = 1/2kx2

Mechanical Energies


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energy stored within the molecule as translational, rotational and

vibrational energies. Change in the internal energy is usually

manifested by a change in the temperature.

U = f(T)

Internal Energy

translational rotational vibrational

Energy transfer between system and surrounding occurs either in

the form of work or heat

Work (W) refers to mechanical work

W = Fdl

Heat (Q) refers to energy transferred from a hot to a cold object.

Work and Heat


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Enthalpy and Heat


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(1) Average (Mean) and Median

Engineering Measurements

http://bell.mma.edu/~jbouch/Glossary/Precision.html

0

5

10

15

20

25

30

35

52 54 56 58 60 62 64 66 68

52 1

54 4

56 7

58 20

60 35

62 15

64 9

66 2

68 4

Measurement frequency

Average = 60.11 60

Median = 58.9 59

(2) Precision and Accuracy

(1) Precision

is denoted by the number of significant figures in the data

Engineering Measurements


(2) Range, sample variance, sample standard deviation

3.4 x 104 has 2 significant figures



Mathematical Operations(1) Multiplication and division

7.29 0.4 = 2.916 2.9

8 x 100 2.00 = 4.00 4 x 100

(2) Addition and substraction

7.29 + 0.401 + 3.1 = 10.791 10.8

50

54

58

62

66

70

0 5 10 15 20

RUN

Measu

rements

X

X + Sx

X - Sx


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Individual Problems

Chapter 2:Problem 2.2

Chapter 2: Problem 2.13

Chapter 2: Problem 2.35

Team ProblemChapter 3: Problem 3.13

Homework # 1 Feb 14, 2003

Feb 28, 2003(1) Density(mass/volume), specific volume (volume/mass)

is given by kg/m3, g/cm3, lbm/ft3

Chemical Engineering Measurements


Density depends on temperature as material expands during

heating

e.g., VHg(T) = V0(1 + 0.18182 x 10-3T+ 0.0078 x 10-6T2)

Perrys Chemical Engineers Handbook

Specific density (/ref)

usually uses water at 4C as reference

ref = 1000 kg/m3

1.000 g/cm3

62.43 lbm/ft3

Self-study:

(1) Find out about the units Baume, degree API and degree Twaddell


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(1) Density(mass/volume), specific volume (volume/mass)

is given by kg/m3, g/cm3, lbm/ft3



Density depends on temperature as material expands during

heating

e.g., VHg(T) = V0(1 + 0.18182 x 10-3T+ 0.0078 x 10-6T2)

Perrys Chemical Engineers Handbook

Specific density (/ref)

usually uses water at 4C as reference

ref = 1000 kg/m3

1.000 g/cm3

62.43 lbm/ft3

Self-study:

(1) Find out about the units Baume, degree API and degree Twaddell

(3a) Composition:


Mass fraction: xA = mass of A/total mass of mixture

Mole fraction: xA = mole of A/total mole of mixture

(3b) Concentration:

Mass concentration = mass of A/volume of mixture

Mole concentration = mole of A/volume of mixture


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(4) Pressure (force/area)

is given by bar, Pa, lbf/ft2


Hydrostatic pressure

P = P0 + gh

P0

gh

PHead

P = gh

Manometer

Example 8. Calculate the pressure a scuba diver experience at 100m beneath the surface of the ocean.


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Example 9. The manometers shown in the figure was used tomeasure the pressure at point 1 and 2 along a section of a piping.

Please determine the value of P1 and P2 in Psia.

Documents

Chem Lecture 1