Elementary Principles Of Chemical Processes - Third Edition text

ELEMENTARY

PRINCIPLES

OF CHEMICAL

PROCESSES

RICHARD M. FELDER

RONALD W. ROUSSEAU

FIGURES

Miscellaneous

Factors forUnit Conversions

Atomic

Weights

and Numbers

Psychrometric (Humidity) _{Chart: SI}Units

Psychrometric (Humidity)Chart:

American

Engineering Units

SelectedPhysicalProperty

Data

(molecularweights,specific gravitiesofsolids

and

liquids melting

and boding

points,heats of fusion

and

vaporization,critical temperature

and

pressure standard heatsofformation

and

combustion)

Gas Laws (PVT Relations) Gas

Constant

Standard

_{Conditionsfor}

Gases

PitzerAcentricFactors

Compressibility Charts

Vapor Pressure Data Cox Chart Vapor

Pressure Plots

Vapor

Pressure of

Water Antoine Equation

Constants

Thermodynamic Data Heat

Capacities

PropertiesofSaturated Steam:

Temperature

_Table Properties ofSaturated Steam:PressureTable Properties ofSuperheated

Steam

Specific Enthalpiesof Ideal

Combustion

_{Gases: SI Units}

SpecificEnthalpies of Ideal

Combustion

Gases:

American

Engineering Units

Atomic Heat

Capacities forKopp's

Rule

Integral

Heats

of Solution

and Mixing

at

25°C

Data for

Specific

Systems

Triangular

Phase Diagram

for

Water-Acetone-Methyl

_Isobutyl

Ketone

at

25°C

Enthalpy-Concentration

Diagram

for

H

2

S0

₄

-H

₂

0

Enthalpy-Concentration

Diagram

for

NH

₃

-H

₂

0

facing

page

back cover 385 386

628-634

back

cover 194 201 208-211

247 638-639 640-641

635-637 642-643 644-649 650-651 652 652 653 653

274 399 403

FACTORS FOR UNIT CONVERSIONS

Mass

Length

Volume

Force

Pressure

Energy

Power

EquivalentValues

1 kg

=

_{1000 g}

=

0.001 metricton

=

2.20462lb

m =

35.27392 oz

1lb

m =

16oz

=

₅

x

^10~4 ton

=

453.593 _g

=

0.453593

kg

1

m =

¹⁰⁰

cm =

¹⁰⁰⁰

mm =

^{106 microns}(|xm)

=

10¹⁰angstroms (A)

=

39.37in.

=

3.2808ft

=

1.0936

yd =

0.0006214 mile

1 ft

=12

in.

=

_1/3

yd =

0.3048

m =

^30.48

cm

1

m

³

=

¹⁰⁰⁰

L =

¹⁰⁶

cm

³

=

¹⁰⁶

mL

=

35.3145 ft3

=

220.83 imperial gallons

=

264.17 gal

=

1056.68 qt

1 ft3

=

1728in.³

=

7.4805gal

=

0.028317

m

³

=

28.317

L

=

28,317

cm

³

1

N =

¹ kg-m/s²

=

10⁵ dynes

=

10⁵ g-cm/s²

=

0.22481 lb_f

1lb_f

=

32.174lb

m

^-ft/s2

=

4.4482

N =

4.4482

X

10⁵ dynes

1

atm =

1.01325

x

10⁵

N/m

² (Pa)

=

101.325

kPa =

1.01325bar

=

1.01325

x

10⁶ dynes/cm²

=

760

mm Hg

^at0°C(torr)

=

^10.333

m H

2

0

at

4°C

=

14.696lb_f/in.2

(psi)

=

33.9ft

H

2

0

^at

4°C

=

29.921 in.

Hg

at

0°C

1 J

=

1

N-m =

10⁷ ergs

=

10⁷

dyne-cm

=

2.778

x 10"

⁷

kW-h =

0.23901cal

=

0.7376ft-lb_f

=

9.486

x

^10~4

Btu

1

W =

^{1 J/s}

=

^{0.23901 cal/s}

=

^0.7376ft-lbf/s

=

9.486

X 10"

⁴ Btu/s

=

1.341

x

^10~3

hp

Example: The

factor toconvert

grams

tolb

m

^is

this page intentionally left blank

ELEMENTARY

PRINCIPLES

OF CHEMICAL PROCESSES

2005 Edition

with Integrated Media and Study Tools

this page intentionally left blank

2005 Edition

with Integrated Media and Study Tools

ELEMENTARY

PRINCIPLES

OF CHEMICAL

PROCESSES

Third Edition

Richard M. Felder

Department of Chemical

Engineering

North

CarolinaState University Raleigh,

North

Carolina

Ronald W. Rousseau

School of Chemical & Biomolecular

Engineering

Georgia

^Institute

of Technology

Atlanta,

Georgia

John Wiley & Sons, Inc.

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No

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WILEY

(225-5945).

ISBN

0-471-68757-X

PrintedintheUnitedStates ofAmerica 10

98765432

Thisbookisprintedonacid free paper.

©

Dedication

We dedicate

this

book

to

our

first

and most important

teachers,

our parents:

the late Shirley Felder,

Robert

Felder,

Dorothy Rousseau, and Ivy John Rousseau.

this page intentionally left blank

About the Authors

Richard M.

Felderis

Hoechst

CelaneseProfessor Emeritusof

Chemical

Engineering_at

North

Carolina State University.

He

received the B.Ch.E. degree

from

the City College _of

New York and

thePh.D.inchemical engineering

from

PrincetonUniversity,

and

he

worked

forthe

Atomic Energy

Research Establishment (Harwell, England)

and Brookhaven

National Lab- oratory beforejoining the

North

Carolina State faculty.

He

hasauthored orcoauthored over

200

papers

on

chemical process engineering

and

engineering education

and

presented hun- dredsof seminars, workshops,

and

shortcourses in bothcategories toindustrial

and

research institutions

and

universities throughoutthe

United

States

and

abroad. Since 1991 he has co- directed theNationalEffective TeachingInstitute

under

the auspices of the

American

Society forEngineering Education.

He

isa

member

of the Publication

Board

of

Chemical

Engineering Education

and

since 1988 has written the

"Random Thoughts" column

for that journal. His

honors

include the R.J.

Reynolds Award

for Excellence in Teaching, Research,

and

Exten- sion, the

AT&T Foundation Award

for Excellence in Engineering Education, the

Chemical

Manufacturers Association National Catalyst

Award,

the

ASEE

Chester F. Carlson

Award

for Innovation in Engineering Education, the

ASEE Chemical

Engineering Division Life- time

Achievement Award

forPedagogicalScholarship,

and

a

number

ofnational

and

redonal

awards

forhispublications

on

engineering educationincluding the 1988. 1989. 1996.

and

2003

ASEE

WilliamJ.

Wickenden Award

forthe outstanding paper in the Journal of Engineering Education.

Many

^ofhispublicationscanbe

found

at<http://www.ncsu.edu/effectivejeaching>.

Ronald W. Rousseau

holds the CecilJ. "Pete" Silas

Endowed

Chair

and

also chairs the School of

Chemical &

Biomolecular Engineering at the

Georgia

Institute of

Technology He

is

an

executive editor of Chemical Engineering Science, a

member

of the Publication

Board

of

Chemical

Engineering Education,

and

a topic editor for Crystal

Growth and

Design:hehas

been

a

member

of the advisory boards of the Wiley Series in

Chemical

Engineering

and

of Separations Technology,aconsulting editorforthe

AIChE

Journal,

and an

associate editor of theJournal

of

CrystalGrowth.

He was

the editor of the

Handbook of

Separation Process Tech- nology (Wiley, 1987). In addition tohis

commitment

toundergraduate education,hehas

been an

activeresearcherinthefieldofseparation science

and

technology.

Among

the

many

topics his

work

has addressed, recent attention hasfocused

on

thefundamentalsofcrystalnucleation

and growth and

the applications ofcrystallizationscience

and

technology.Hiscontributionsto thefieldofchemicalseparationstechnology

were

recognized throughtheClarence G.

Gerhold Award

ofthe Separations Division of the

American

Instituteof

Chemical

Engineers

(AIChE).

He

isaFellowofboth

AIChE and

the

American

Associationforthe

Advancement

of Science.

He

isa graduateofLouisianaStateUniversity

and

anelected

member

of the

LSU

Engineering Hall ofDistinction.

He

hasservedaschair of the Councilfor

Chemical

Research,

member

of the

Board

ofDirectors of

AIChE, and

chair of the

AIChE

Publication

Committee.

Drs. Felder

and Rousseau were

joint recipients of the 2002

Warren

K.

Lewis Award

for Contributions to

Chemical

Engineering Education

from

the

American

Institute of

Chemical

Engineers.

vii

this page intentionally left blank

Preface to the Third Edition

2005 Edition

with Integrated Media and Study Tools

An

introductorystoichiometry coursetraditionallyplays severalimportant roles inthe

chem-

ical engineeringcurriculum.

On

the

most

obviouslevel, it prepares the student to formulate

and

solve material

and

energy balances

on

chemical process systems

and

laysthefoundation forsubsequentcoursesinthermodynamics,unitoperations

and

transport

phenomena,

kinetics

and

reactor design,

and

process dynamics

and

control.

More

fundamentally,it introduces the engineering

approach

to solving process-related problems: breaking a process

down

into its

components,

establishing therelations

between known and unknown

process^variables,assem- bling the information

needed

tosolvefor the

unknowns

using a

combination

ofexperimenta- tion,empiricism,

and

the application of naturallaws,and,finally,putting the pieces togetherto obtainthe desired

problem

solution.

We have

tried inthe

book

tofulfilleachof thesefunctions.

Moreover,

recognizingthatthe stoichiometry course isoften the students'firstrealencounterwith

what

theythink

may

betheir

chosen

profession,

we have

attempted toprovide in thetext arealistic,informative,

and

pos- itiveintroduction tothe practice ofchemicalengineering. In thefirstchapter

we

surveyfields thatrecentchemical engineeringgraduates

have

entered,

from

traditionalindustrialchemistry

and

petroleum engineering to materials engineering, environmentalscience

and

technology, biomedical, biochemical,

and

geneticengineering, informationtechnology, law,

and

medicine,

and we

describe the variety of research, design,

and

production

problems

engineers typically confront. In therestof the

book we

systematicallydevelopthe structureofelementaryprocess analysis: definitions,

measurement, and

calculationofprocessvariables; conservationlaws

and thermodynamic

relations that govern the

performance

of processes;

and

physical properties ofprocess materialsthat

must

be determinedinordertodesign a

new

processoranalyze

and improve an

existingone.

The

chemical processconstitutes the structural

and

motivational

framework

for the pre- sentationofallof thetext material.

When we

bringinconcepts

from

physical chemistry

—

^for

example, vaporpressure,solubility,

and

heatcapacity

— we

introduce

them

asquantities

whose

values are required todetermine process variables orto

perform

material

and

energy balance calculations

on

a process.

When we

discusscomputational techniques suchas curve-fitting, root- findingmethods,

and

numericalintegration,

we

present

them on

the

same need-to-know

basis inthe context of processanalysis.

FEATURES

Industrial

Process Case Studies

An

important^{feature ofthe}

book

is a setofindustrial process case studies that demonstrate theroleofsingle-unitcalculationsintheanalysisof multiple-unit processes.

We have

designed the casestudies tobe

worked on

as

term

projects

by

individualsor (preferably) smallteamsof

ix

students,beginningafterthe students

have completed

the introductorychapter

on

materialbal- ances (Chapter4).Ineachstudy,thestudents areaskedto

produce

aflowchart of amoderately

complex

process

from

a givendescription,to

perform

material

and

energy balancecalculations

on

the process,

and

toanswerquestionsthatrequire consideration of

how

the overallprocess

is structured

and why

itmight bestructured that way.

Knowing

the

problems

associated with the case study,the students tend to be

on

the lookoutfor course content that will help

them

obtain the requiredsolutions.

The

casestudy thus provides both motivationfor learning the textmaterial

and

afeeling for thecontextualsignificance ofthis material.

SI Units

SI units are used widelybut notexclusivelythroughoutthe text,

and

extensive SIdata tables, including

steam

tables, arecontainedintheappendices.

Interactive Chemical Process

Principles

CD

The

InteractiveChemicalProcesses Principles

CD

inthe

book

contains:

• instructional tutorials,

• a learningstyle assessmenttool,

• physicalpropertylookuptableswith

an embedded

routineforcalculating sensible heats,

• VisualEncyclopedia

of

Chemical Engineering Equipment,

•

E-Z

Solve.

(Seepagesxiv-xvi for a

more

detailed description.)

Computational Software (E-Z Solve)

Computer programming

is not covered explicitly, but

problems

_that lend themselves to

j(g0

computer-aided solution are given after each chapter.

An

exceptionally robust

and

user- E-Z Solve friendly equation-solving

program (E-Z

Solve) included

on

the Interactive

Chemical

Process Principles

CD makes

it possible for students to analyze relatively large processes without havingto

spend

excessive time

on

algebraic

and

numericalcalculations.

Website

Updates

tothetext

and

additional resources to supportitsuse

may be found

at

<http://www.ncsu.edu/felder-public/EPCP.html>

• Erratalisting—anyerrors

found

inthetext willbe listed

on

the website.

• Illustrativecourse

Web

site

— A home page from

the material

and

energy balance course at

N.C. State University containing_{links to} the coursesyllabus, policies

and

procedures, class handouts, studyguidesforexams,

and

oldexams.

•

Handouts

for

students—

Tips

on

maintaining confidence, taking tests,

and

identifying

and

takingadvantageof learning resources

on

campus.

•

Index

ofLearningStyles

— A

self-scoringinstrumentthatallows students(andinstructors) to determinetheirlearningstylepreferences.Aftertaking thetest,userscanobtaininformation aboutthe strengths oftheirlearningstyles

and

suggestionsfor

how

toget

more

outoftheir courses. (Also

on

the

CD

^insidethetext)

• "Stoichiometry

Without Tears'— An

^article

from Chemical

Engineering Education offering suggestions forteaching the stoichiometry course.

Preface totheThird _{Edition xi}

Resources on the publisher's website

Visitthe website at <http://www.wiley.com/college/felder> to access various resources.

Some

resources are password-protected,

and

available only to instructors using _this text in their course. Visitthe Instructor

Companion

Siteportion ofthis website toregisterfor apassword.

ACKNOWLEDGMENTS

We acknowledge

withgratitude the contributions of colleagues

and

students

who

have helped us since

we began work on

thefirstedition.

Our

thanks goto

Dick Seagrave and

thelate Pro- fessors

John

Stevens

and David

Marsland,

who

readtheoriginalmanuscript

and

offered

many

helpful suggestions forits

improvement;

ourfirst

department

head, thelate

Jim

Ferrell,

who

gave us invaluable

encouragement when we

brashly(and

some

mightsay,foolishly) launched into the

book

as

young

assistant professors;

and

ourcolleagues

around

the

world who

helped us prepare the case studies

and

suggested

improvements

in thethree successive editions.

We

raiseourglasses tothestudentsintheFall1973offering of

CHE

205atN.C. State,

who had

the

bad

lucktoget thefirstdraft asacourse text.

We're

sorry

we

never

managed

togettoenergy balances with them,

and we hope and

trustthattheyeventuallylearned

them somewhere. We

also thankthe

many

N.C. State

and

Georgia

Tech

studentsinsubsequent years

who

took the trouble topoint outerrorsin the text,

who we know

did it out of a sense of professionalre- sponsibility

and

notjust to collectthequarters.

We

thank

Rebecca and Sandra

for

many

years of unfailing

encouragement and

support,

and

last

and most

ofall,

we thank

Magnificent

Mary Wade, who

uncomplainingly

and

with great

good humor

typed revision after revision of the

firstedition,untilthe authors, unabletostandany more,declared the

book

done.

Notes to Instructors

Suggestions

for

chapter coverage

The

organization of this text has

been

planned to provide

enough

flexibility to

accommo-

date classes with diverse

backgrounds

_{within the scope of a} one-semester or two-quarter course.

We

anticipatethatsemester-longcoursesin

which most

students

have

traditional_first- year engineering

backgrounds

will cover

most

of the first nine chapters, possibly

augmented

with

one

case study.

A

one-quarter course should cover Chapters ¹ through6. Students

who have been exposed

todimensional analysisand elementary data correlationcanskip orskim

Chapter

_2,

and

students

whose freshman

chemistry coursesprovided a detailed coverage of process variabledefinitions

and

the systematic use ofunits to describe

and

analyze chemical processes

may

omit

Chapter

3.

The

time gained as a result of these omissions

may

be used to cover additional sections in Chapters4 through 9, to

add Chapter

10

on

computer-aided balances or

Chapter

₁₁

on

transient balances, or to cover

appended

material

on

numerical analysis.

Teaching and promoting a systematic approach

to

process

analysis

We have

consistently

found

that the key tostudent successin thestoichiometry course is ap- proaching the

problems

systematically: drawing

and

labeling flow charts, counting degreesof

freedom

to

make

surethat

problems

aresolvable,

and

formulatingsolution plans beforedoing

any

calculations.

We have

also

found

thatstudents are

remarkably

resistant tothisprocess, pre- ferring to launchdirectly intowriting equationsinthe

hope

thatsoonerorlatera solutionwill

emerge.

The

students

who make

the transition to the systematic

approach

generally

do

well, while those

who

continue toresistitfrequently fail.

Homework problems and assignment schedules

In our experience, the only

way

students learn to use this

approach

is

by

repeatedly prac- ticing it.

Hundreds

of chapter-end

problems

in the text are structured to provide this prac-

tice. Representative assignment schedules are given in the Instructor

Companion

Site at

<http://www.wiley.com/college/felder>,

and

thereis

enough

duplication of

problem

types for theschedulestobevariedconsiderably

from

one course offeringtoanother.

Student Workbook New!

A new

feature ofthis

updated

editionistheavailabilityof asupplementary

workbook

contain- ing detailed outlines of solutions to selected chapter-endproblems, withspacesforstudentsto insert equations

and

numericalsolutions.

Working

through these

problems

willhelp students

become

comfortable with the systematic approach sooner rather thanlater.

We

suggest that

workbook problems

be included inregular

homework

assignments, but at thevery least, in- structorsshould encouragetheirstudents _{to solve}the

problems on

^their

own. Problems

inthe

Workbook

are designated

by

aniconin themarginofthistext.

Student Workbook

xii

Notesto Instructors xiii

Developing

creativity

with open-ended problems

In additiontothebasicmaterial

and

energy

problems

atthe

end

of the chapters,

we

have pro- vided a variety of

open-ended

problems thatfocus

on

conceptual understanding and creative thinking, both

imbedded

within chapter-end

problems and

asseparate "CreativitvExercises."

We

encourageinstructors to assignthese

open-ended problems on

a regularbasis

and

perhaps to include similar problems

on

tests after

ample

practice has

been

provided in assignments.

The problems

can beintroduced ina variety ofways: asfocalpoints for in-classbrainstorming sessions, as parts of regular or extra-credit

homework

assignments, or asindividual or group projects with rewards (e.g.,

bonus

points

on

subsequent tests) for the solutions exhibitingthe greatest fluency (quantity ofsolutions). Far

more

than the algorithmic drills, these exercises

convey

a sense of the challenging

and

intellectuallystimulatingpossibilities in achemicalengi- neeringcareer.

Conveying

thissense

may

be the

most

valuable task thatcan be accomplished inthe introductorychemicalengineering course.

Using the case studies

We have

discussed in the Preface the motivational aspects of the case studies and the

way

the studies

complement

the formal ^text material.

An

additional benefit occurs ifthe assign-

ments

are

made

togroups, an approach

we

regularlyuse in ourclasses.

We

invariably see the groupsstartingoutin a state ofsemi-anarchy

and

then developingcohesivenessas the

weeks go

by.

By

the

end

of the term

most

students

have

learned

how

to divide the labor appropri- ately

and

tolearn

from one

another, since they

know

they are liable to be tested

on

any

pan

of the project

and

notjustthe part for

which

they

were

personally responsible. This isthe

pan

of the course the students usually say they enjoyed most.

We

have also found that periodic conferences

between

the groups

and

the instructor to discuss the case studiesprovide

added

educationalbenefits toallpartiesconcerned.

Resources

for instructors

The

Instructor

Companion Web

Site contains resources for instructors, including illustrative

assignmentschedules, reproducible copies offigures in the text,

and problem

solutions.

The

password-protectedsiteisaccessibleonlyto instructors

who

areusing thetext for theircourse.

Go

^to <http://www.wiley.com/college/feldcr>

and

click

on

the link to "Instructor

Companion

Site"to register forapassword.

RMF

Interactive Chemical Process Principles

(CD near front of text)

The CD

that

accompanies

this edition of the textcontains a variety of resources for students

and

instructors collected

under

the titleInteractive

Chemical

Process Principles

(ICPP) Some

of the

components

of

ICPP

areinstructional aids forthe stoichiometry course,

and

others are computational

and

referencetools thatshould proveusefulthroughoutthechemicalengineer- ing curriculum.

One

or

more

of the

ICPP

toolscan be effectivelyapplied toalmost every ex-

ample and problem

inthe book. Icons throughoutthe

book remind

students

and

instructors

when

the tools

on

the

CD may

behelpful.

Inthissection,

we

provide an overviewof

ICPP and some

thoughts

on how

it

might

be used effectivelyas an adjunctto thetext.

We

encourage

you

to read through thisoutline

and

then explorethetools for yourself.If

you

are a student,

you

will

soon

beabletorecognize

when you

can use the tools for

problem

solving;if

you

arean instructor,

you

will see

when

suggestions for using the toolsmight behelpfulinyourlecturenotes or assignments.

Index of Learning

Styles

£Bk

^Students learn in a variety of ways. For example,

some

students are concrete

and

practical

These

students appreciate

many

illustrations, examples,

and

applications of course material What ^is your

and

are uncomfortable with abstract mathematical presentations.

Other

students are

much

Learnmg _Style?

more

comfortable with abstraction

and

are easily

bored by

repetitive calculations

and exam-

ples.

Some

learn visually, getting

much more from

pictures

and

diagrams than they

do from words and

formulas, while others_benefit

more from

verbal explanationsthan

from

visualrep- resentations.

The

^listofsuchdifferences isendless.

A

student's learningstyleisasetof preferences for certain

ways

of takingin

and

processing information.

The

Index ofLearning Styles (ILS) is

an

instrument that enables

you

to assess several of

your

learning _style preferences.

We

sugggest that the first thing

you do when you

beginto explore

ICPP

is tocomplete the ILS,determine

your

learningstyle profile

and

then readthe

accompanying

materialthatsuggests studystrategies(if

you

are a student)orteaching

strategy

(if

you

are

an

instructor) that might

work

effectively for

you

in the stoichiometry course

and

insubsequentcourses.

Instructional Tutorials

ICPP

contains six interactive _tutorials,designed forstudents to

work

throughafter they have progressed tocertain points in the text. Ineach tutorial, process descriptions are given, ques-

Interactive tlons are posed,

and

students enter answers

and

receive affirmation or corrective feedback

Tutorials

and

then

go on

toadditional_questions.Process simulations arealsoincluded sothatstudents

may

predict

how

processsystemswill respondtochangesincertainsystem_variables

and

then explore the effects of those changes experimentally.

The

active involvement

and immediate

feedback implicit intheseexercisescansignificantlyreinforcelearning.

iv

Interactive

Chemical

_{Process Principles xv}

Once

studentscansuccessfully

work

throughatutorial

from

beginningtoend,they

may

be confidentthattheyhave

mastered

asignificantportion of the material

covered

_{in that} tutorial.

If they

have

repeated trouble with a part of the ^tutorial, theywill be able to identifygaps in theirunderstandingof thecoursematerial

and

gethelp withthem.

The

tutorials

and

the pointsinthecourse

when

they

may

be

completed

areas follows:

1. Basic process calculations

and

^processsystemvariables(endof

Chapter

_3).

2. Material balances

on

nonreactivesingle-unitprocesses(end ofSection4.3).

3. Material balances

on

reactive multiple-unitprocesses(endof

Chapter

4).

4. Material balances

on

multiphase systems (endofChapter6).

5. Material

and

energy balances

on

nonreactiveprocesses (endof

Chapter

8).

6. Material

and

energy balances

on

reactive processes(endof

Chapter

9).

Physical Property Database

Th

e physical propertydatabaseof

ICPP

^containseasilyaccessed values ofmolecularweights,

I V

^{specificgravities,phase}transition points,criticalconstants,vaporpressures,heatcapacities,

and

Physical Property ^latent heatsfor

many

species thatduplicate the values foundin

Appendix B

of the text.

The

Database values retrieved

from

the database

may

be incorporated into process calculations

performed

using

E-Z

Solve.

The

principalbenefitto studentsisabuilt-infunctionforintegrating tabulated heat capac- ities

between

specifiedtemperaturelimits.

Without

this tool,polynomial formulasinTableB.2 of the text

must

beintegratedterm-by-term

and

theinitial

and

finaltemperatures

must

been- teredasthelimits,with tedious calculationsbeingrequiredforthe associated arithmetic.

With

the Physical Property

Database

tool, the desired speciesis selected

from

a pull-down

menu,

theinitial

and

final temperaturesaretypedin,

and

asingle clickleads ^tothe calculation ofthe integral.This feature willbe

most

helpfulinChapters8

and

9of thetext.

Visual Encyclopedia of Chemical Engineering Equipment

/4^fcy

Most

of theexamples

and problems

inthetextrefertoitems of

equipment commonly

foundin

I I

^{chemicalprocesses,such}as reactors,heat exchangers, distillationcolumns, absorption towers.

Equipment crystallizers,filters,

and

centrifuges.In

some

cases, briefexplanations of these

equipment

items Encyclopedia are given;inothers,thetermsaresimplyused.

The

VisualEncyclopedia

of Chemical

^Engineer- ingEquipment,created

by

Dr.Susan

Montgomery

of the University ofMichigan,containspho- tographs,

cutaway

diagrams,movies, animations,

and

explanations of

how

the differentequip-

ment

itemswork. Itshouldbeconsultedto clarifyreferencestoprocessunits inthetextandto betterunderstand

how

the processesdescribedinthechapter-end

problems

work.

E-Z Solve

^flk E-Z

^{Solve is apowerful}

and

user-friendlyequation-solving

program

designed

and

writtenby

M M

Intellipro, the

company

that

produced

ICPP. It can be used to obtain numerical solutions of E-ZSolve sets°fhnear

and

nonlinear algebraicequationsof the typesthatoccurinalmost everychapter-

end problem

in Chapters 4 through 10 of the text,

and

itcan also solve ordinarydifferential equations of the types ^that occur in

Chapter

11.

Examples

of applications of

E-Z

Solve to representative stoichiometryproblemsareprovided

on

the

CD. E-Z

Solve^isconvenienttouse

whenever

a

problem

callsforsolving three or

more

simultaneouslinearalgebraic equations or

any number

of nonlinear algebraicequations

and

ordinarydifferentialequations.

We

have found an interesting

phenomenon

associated with

E-Z

Solve,

and

^{that is that}

many

students

do

notuse itunless they are ^initiallyrequired to

do

so, probably becausethey areworriedaboutthetimeitwilltake

them

tolearnhow.

The

resultisthat the studentsspend

hours slogging through

manual

solutions of equations that could be solved in minutes with thrnnah

;?r

e Y

T

^&

^ ^ tW ° °

^r

^ ^ however

^>

^ «™

^{toitconstantly}

throughouttheremainder_{of the} chemical engineering curriculum

unkno W

^1VC

^^."P

^l

°

^itS

name

^-

Here

^{'forexa™Ple, are threeequationsinthree}

unknowns *

_B

, 7/dp)thatanseaspart ofa

problem

in

Chapter

6

(1)

_

^0.980(760)

_

^0.020(760)

' " "

io⁶

-84471

-^

^{(2) XB}

=

⁽³⁾

„ +

^xB

=

¹

fftne^tTatr^T

^f

done

withasimplecalculator,^,nUally

and 'T^

not too

^

difficult

^ ^

for a spreadsheet.

" W °

^Uldbe3

To

^Ionuse^§

and E-Z

^tediousSolve the following threelinesof

code would

be typedin:

xa = 0.980 V60/10A (6.84471-1060.793/(Tdp+231

₅₄₁₎₎

xb = 0.020*760/10 A

(6.88555-1175.817/(Tdp+

_224.867))

X9 + xb —

1

0 °;;l h !Sr

^S

T

^en

?

^ed'3C

° mmand

^{t0 "S}

°

^1Ve"

WOuld

^{be entered folJ}

owed by

^aclick

on OK, and

the solutionfor _all three variables

would

immediately_appear.

T^e

longer

and more complex

thetextproblem, the greater the timesaving that results

from

_using

Evolve

ha" rTfT

^8fba,anCe eqUatl°nS

^

^PhyS1Cal

« estimatiL "0^

mat anse

intne course ofitssolution.

Nomenclature

The

variablestobe listedwill

be

expressed inSIunits forillustrativepurposes, but theycould equally^well

be

expressedin

any

dimensionallyconsistentunits.

a,b,c,d

C

_p [kJ/(mol-K)],

C

v [kJ/(mol-K)]

£*(kJ),£*(kJ/s)

£

_p

(kJ),£

p(kJ/s)

£f(m/s²₎

#(kJ),tf(kJ/s),tf(kJ/mol)

m,M

(kg), m(kg/s)

n(mol),

n(mol/s)

pA (N/m

²⁾

p*

A (T)(Wm

²₎

P(N/m

²₎

P

C

(K)

Q(kJ),!2(kJ/s)

^[kJ/tmol-K)]

Eitherarbitraryconstants orcoefficients of a

polynomial

expressionfor heatcapacity,

such

as thoselisted in

Appendix

B.2.

Heat

capacities atconstantpressure

and

constant

volume,

respectively.

Kinetic energy,rate of kinetic

energy

transport

by

a flowingstream.

Potential energy, rate of potential

energy

transport

by

^a flowing stream.

Gravitational accelerationconstant,

equal

to 9.8066

m/s

² or 32.174ft/s2

atsealevel.

Enthalpy

ofa

system

(H), rate of transport of enthalpy

by

a process

stream

(H),specific

enthalpy

(H), all

determined

relativeto a specifiedreference state.

Mass (fflorM)

or

mass

flowrate (m) ofaprocess

stream

or

stream component.

Number

of

moles

(n)or

molar

flow rate (h)ofa process

stream

or stream

component.

Partialpressure of species

A

in a

mixture

of

gaseous

species,

= y\P.

Vapor

pressure of species

A

^at

temperature T

.

Totalpressure ofa system.

Unless

specificallytold otherwise,

assume

that

P

isabsolute pressure

and

not

gauge

pressure.

Critical pressure. Valuesofthis

property

are listedin

Table

B.l.

Totalheattransferred toor

from

a

system

_(Q), rate ofheattransfertoor

from

a

system

(Q).

Q

^is

definedto

be

positive ifheatistransferred to the system.

Gas

^constant,givenindifferentunits

on

the inside

back cover

of the text.

xvii

xviii

Nomenclature

SCMH, SCLH, SCFH

SG

f(s)

T(K)

U(kJ),

t)(kJ/s), tf(kJ/moI)

Abbreviations

_forstandard cubic

meters

per

hour [m

³(STP)/h], standard_liters

per hour

[L(STP)/hj,

and

standard cubicfeetper

hour

^[ft3(STP)/h]

respectively: the volumetric flowrate of agas

stream

ifthe

stream were brought from

itsactual

temperature and

pressuretostandard

temperature and

pressure (0°C

and

1 atm).

Specificgravity, orratio ofthe density ofa species to thedensity ofareference species.

The

abbreviation

is always

used

for liquids

and

solids in this text

and

usually refers to species for

which

specific gravities arelisted in TableB.l.

Time

Temperature

Melting

point temperature, boilingpoint

temperature,

and

criticaltemperature, respectively.

Values of these properties arelisted inTable B.l.

Internal

energy

ofa

system

(£/),rate of transport of internal

energy by

aprocess

stream

_(£/), specific internal

energy

(U), allrelative to a specified referencestate.

V (m

³), V,v

(m

³/s),

V(m

³/mol)

Volume

(V) ofafluid or processunit,volumetric flowrate

(V

orv) ofa process stream,specific

volume

(V) ofaprocess material.

W(kJ), W

s(k3/s)

Work

transferred toor

from

a

system

(W),rate oftransferofshaft

work

toor

from

acontinuous process

system (W

s).

W

^is definedto

be

positive (in this text)if

work

is transferred

from

a

system

toits

surroundings.

Mass

fractionor

mole

fraction of a speciesina mixture. (Subscriptsare usually

used

to identify the species.)In liquid-vaporsystems,

x

usuallydenotes fractionin the liquid

and y denotes

_{fractionin the} vapor,z

may

also

denote

the compressibility factor of a gas.

Greek

letters

AH

C,Atf/(kJ/mol)

AH m

,

A#„(kJ/mol)

In batch(closed) systems,

AX denotes

the difference

^finai

—

_initial,

where X

^is

any system

property.

In

continuous (open)

systems, A.Xdenotes the difference

X

output

- X

input^.

Heats

of

combustion and

formation, respectively.

Values ofthese properties at

25°C and

1

atmosphere

arelistedin

Table

B.l.

Heats

ofmelting_(fusion)

and

vaporization, respectively. Values of these propertiesatthe

Nomenclature

xi\

f(mol)

£(mol/s)

p(kg/m

³₎

normal

melting

and

boiling points are listed in

Table

B.l.

Stoichiometriccoefficient ofspecies

A

in a chemical reaction,defined to

be

positive for products,

negativefor reactants.

For N

2

+ 3H2 —

_*

2NH

3^.

vn

₂

= —

_1' v

h

₂

- -

3,

fNH

₃

=

^2.

Extent

ofreaction. If/lAo(mol) of reactive species

A

^{isinitiallypresentina reactor}

and

^{/iA(mol) is}

present

some

timelater, then theextent of reaction atthat

time

is£

=

_(«A0

-

n

A

^)/ f a>

where

v

A

^isthe stoichiometriccoefficient of

A

^{in thereaction (see}

preceding

definition).

The

value of£ isthe

same

regardlessof

which

reactantor

product

is

chosen

asspecies

A.

Extent

of reactionfor acontinuous process atsteady state. If/iAo(mol/s)

0

freactive species

A

^enters

the reactor

and

n

A

^{(mol/s) exits,}

then

theextentof

reactionist =

_{(n A0}

-

h

A

^)/

v

A

^,

where

v

A

^isthe

stoichiometriccoefficientof

A

ⁱⁿthe reaction.

The

value of

£

^isthe

same

regardlessof

which

reactant or

product

is

chosen

as species

A.

Density.

Other Symbols

"

(e.g.,

m)

'(e.g.,

0)

()

Flow

^rate,

such

as

mass

flowrate.

Specificproperty,such asspecificinternalenergy.

Parentheses

are

used

to express functional

dependence,

as in p*(T) to

denote

a

vapor

pressure that

depends on

temperature,

and

also to enclose unitsof variables, as in

m(g)

to

denote

^a

mass

expressed

ingrams.

The

intended use

can

usually

be

easily

seen

incontext.

this page intentionally left blank

Glossary of Chemical Process Terms

Equipment Encyclopedia

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Equipment Encyclopedia

Absorption

A

^{processinwhich}agasmixture contactsaliquid solventandacomponent(or severalcomponents)ofthegasdissolvesinthe liquid.Inanabsorptioncolumnorabsorption tower(orsimplyabsorber), the solvent enters the topof acolumn,flowsdown, and emergesatthe bottom,andthe gasentersatthebottom,flows up(contactingtheliquid),andleavesatthetop.

Adiabatic

A

termappliedtoaprocessinwhich noheatistransferredbetweentheprocess systemanditssurroundings.

Adsorption

A

^{processinwhichagasor liquid}

mixture contacts asolid (theadsorbent)anda mixturecomponent(the adsorbate)adheresto the surfaceof thesolid.

Barometer

A

^devicethatmeasuresatmospheric pressure.

Boiler

A

processunitinwhichtubespass throughacombustion^furnace.Boilerfeedwater

isfed intothetubes,andheattransferredfrom thehotcombustionproducts throughthetube wallsconverts the feedwatertosteam.

Boilingpoint(ata givenpressure) Forapure species,the temperatureatwhichthe liquid andvaporcancoexistinequilibriumatthe given pressure.

When

appliedtotheheatingof a mixture ofliquidsexposedtoagasatthegiven pressure,the temperatureatwhichthemixture begins toboil.

Bottomsproduct Theproductthat leavesthe bottomofadistillationcolumn.Thebottoms productisrelativelyrich inthelessvolatile

componentsof the feedto thecolumn.

Bubblepoint(ofa mixtureofliquids atagiven pressure) Thetemperatureatwhichthe firstvapor bubble^appearswhenthemixture

isheated.

Calibration (ofa processvariablemeasurement instrument)

A

^{procedureinwhichan}

instrumentisusedtomeasureseveral independentlyknownprocessvariable values, anda calibrationcurveofknownvariable valuesversusthecorresponding instrument readingsisplotted.Oncetheinstrument has beencalibrated,readings obtained withitcan be convertedto equivalentprocess^variable values directlyfromthe calibration curve.

Catalyst

A

^{substancethat}significantlyincreases the rateof achemicalreaction,althoughitis

neither a reactantnora product.

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Compressibilityfactor _z

= PV/nRT

foragas.If z

=

1,then

PV = nRT

(the ideal gasequation ofstate)andthe gasissaid tobehaveideally.

Compressor

A

devicethatraisesthepressureof agas.

Condensation

A

processinwhich anentering gasiscooled and/or compressed, causingone ormoreof thegascomponentstoliquefy.

Uncondensedgasesandliquidcondensateleave thecondenserasseparatestreams.

Criticalpressure,P, Thehighestpressureat

whichdistinctvaporandliquidphasescan coexist foraspecies.

Criticaltemperature,

T

e Thehighest

temperatureatwhichdistinctvaporandliquid phasescancoexist foraspecies.Thecritical temperatureandpressure,collectivelyreferred toasthecritical constants, arelistedforvarious speciesinTableB.l.

Crystallization

A

processinwhichaliquid solutioniscooled,orsolvent^isevaporated,to anextent that solidcrystalsof soluteform.The

crystals inthe slurry(suspensionofsolids ina liquid)leavingthecrystallizer

may

subsequently beseparatedfromthe liquidinafilteror centrifuge.

Decanter

A

deviceinwhich twoliquidphasesor liquidandsolidphasesseparatebygravity.

Degreesoffreedom

When

applied to ageneral process, the differencebetweenthenumberof

unknownprocessvariablesandthenumberof equationsrelatingthosevariables; thenumber

ofunknownvariables forwhichvaluesmust bespecifiedbeforetheremainingvaluescan becalculated.

When

appliedto asystemat equilibrium, thenumberof intensivesystem variables forwhichvaluesmustbespecified beforetheremainingvaluescan becalculated.

Thedegreesoffreedominthesecond sense^is determinedusing theGibbs^PhaseRule.

Dew

point (of a gasmixture) Thetemperatureat

whichthefirstliquiddropletappearswhenthe mixtureiscooledatconstantpressure.

Distillation

A

processinwhichamixtureoftwo ormorespeciesisfedtoaverticalcolumnthat contains either aseriesofverticallyspaced horizontalplates,or solidpacking through whichfluidcanflow.Liquid mixturesof thefeed componentsflowdownthecolumn andvapor mixtures flowup.Interphasecontact,

XXI

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partialcondensationof the vapor,andpartial vaporization of the liquidalltake place throughout_thecolumn.Thevaporflowing upthecolumn becomesprogressively richer inthemorevolatilecomponentsof the feed, andtheliquidflowingdownbecomesricherin thelessvolatilecomponents.Thevaporleaving thetopof thecolumniscondensed:partof the condensateistaken_{off as the}overhead product andtherestisrecycled to the reactor asreflux,

becomingthe liquidstreamthatflowsdown

thecolumn.Theliquidleaving thebottomof thecolumnispartiallyvaporized: thevapor

isrecycled to the reactor asboilup,becoming thevapor streamthat flowsupthecolumn,and the residual liquidistakenoff as thebottoms product.

Drying

A

processinwhichawetsolidisheated orcontacted withahot gasstream, causing

someoralloftheliquidwetting thesolidto evaporate.The vapor andthe gasitevaporates intoemergeasoneoutlet stream,andthesolid

andremainingresidual liquidemergeas a secondoutletstream.

Enthalpy(kJ) Property_ofa system_{defined as}

H = U +

PV, where

U =

internal energy,

P = absolute pressure,andV

=

_{volumeof the}

system.

Evaporation(vaporization)

A

processinwhich apureliquid,liquidmixture,orsolventina solutionisvaporized.

Extraction(liquidextraction)

A

processinwhich aliquidmixtureoftwospecies (the soluteand thefeedcarrier)iscontactedinamixer witha third liquid(the solvent) thatisimmiscible or nearlyimmiscible withthefeedcarrier.

When

the liquids are contacted, solute transfersfrom the feed carrier to the solvent.The combined mixtureisthen allowedto_settleintotwophases thatarethen separatedbygravityinadecanter.

Filtration

A

processinwhichaslurry ofsolid particlessuspendedina liquid passesthrough a porousmedium. Mostof theliquidpasses throughthe

medium

(e.g.,afilter)toformthe filtrate,andthe solidsandsomeentrainedliquid

are retainedonthefiltertoformthefiltercake.

Filtration

may

alsobe usedto separatesolidsor liquidsfromgases.

Flashvaporization

A

processinwhichaliquid feedatahighpressureissuddenly exposedto alowerpressure,causingsomevaporization to occur.Thevapor productisrich inthemore

volatilecomponentsof thefeedandthe residual liquidisrich intheless volatilecomponents.

Flue_gas Seestackgas.

Heat Energytransferredbetweenasystem anditssurroundingsas aconsequenceof a temperaturedifference.Heatalways_flowsfrom ahigher temperatureto alowerone.

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Heat_exchanger

A

processunitthrough which twofluidstreamsatdifferenttemperatures flowonoppositesidesofametalbarrier.Heat

istransferredfromthestreamatthe higher temperature throughthe barriertothe other stream.

Internalenergy

(V

) Thetotalenergy possessed bythe individualmoleculesinasystem(as

opposedto the kineticandpotential energies of thesystemasawhole).

U

^isastrong functionof temperature,phase,andmolecular structure,andaweakfunctionofpressure(it isindependent of pressurefor idealgases).Its absolutevalue cannot be determined,soitis

always expressedrelativeto a referencestate at whichitisdefinedtobezero.

Membrane

A

thin solidorliquid filmthrough whichoneormorespeciesinaprocess stream can permeate.

Overheadproduct Theproductthatleaves the top_{of a}distillationcolumn.Theoverhead productisrelatively richinthemostvolatile

componentsofthefeedto thecolumn.

Pump A

device usedtopropelaliquidorslurry

from onelocation to another, usuallythrougha pipeortube.

Scrubber

An

absorptioncolumndesignedto

remove anundesirablecomponent froma gas stream.

Settler Seedecanter.

Shaftwork Allworktransferredbetween_a continuous systemanditssurroundings other than thatdone byoronthe processfluid atthe system entranceandexit.

Stack gas Thegaseous productsexitingfroma combustionfurnace.

Stripping

A

processinwhicha liquid containing a dissolvedgasflows

down

acolumn anda gas (stripping gas) flowsupthecolumnat conditionssuchthat the dissolved gascomesout of solutionandiscarried offwiththe stripping gas.

Vaporpressure Thepressureatwhich pure liquid

A

cancoexistwithitsvaporatagiven temperature. Inthis text,vaporpressurescan be determinedfromtabulated data(e.g.,TablesB.3 andB.5-B.7forwater), theAntoineequation (TableB.4),ortheCoxchart (Figure6.1-4).

Volumepercent

(%

^{v/v) For}liquidmixtures, the percentageof thetotalvolumeoccupiedbya particularcomponent;for ideal_gases,thesame

asmolepercent.Fornonidealgases,thevolume percenthasnomeaningfulphysicalsignificance.

Work

Energytransferredbetweenasystem anditssurroundingsas aconsequence_of motionagainstarestrainingforce, electricity or radiation,oranyotherdriving forceexcepta temperaturedifference.

Contents

Preface to the Third Edition

ix

Notes to Instructors

xii

Interactive Chemical Process Principles xiv

Nomenclature xvii Glossary xxi

PART 1 ENGINEERING PROBLEM ANALYSIS 1

Chapter 1 What Some Chemical Engineers Do for a Living 3 Chapter 2 Introduction to Engineering Calculations 7

2.0 InstructionalObjectives 7 2.1 Units

and Dimensions

8 2.2

Conversion

ofUnits 9 2.3

Systems

ofUnits 10 2.4 Force

and Weight

12

2.5

Numerical

Calculation

and

Estimation 13

2.6

Dimensional Homogeneity and Dimensionless

Quantities

20

2.7 Process

Data Representation and

Analysis

22

2.8

Summary

30

Problems

31

Chapter 3 Processes and Process Variables 42

3.0 InstructionalObjectives 43 3.1

Mass and Volume

43 3.2

Flow Rate 45

3.3

Chemical Composition

47 3.4 Pressure 54

3.5

Temperature

60 3.6

Summary

63

Problems

65

PART 2 MATERIAL BALANCES 81

Chapter 4 Fundamentals of Material Balances 83

4.0 Instructional Objectives 83 4.1 Process Classification 84 4.2

Balances

85

4.3 Material

Balance

Calculations 89

4.4

Balances on

Multiple-Unit Processes 104 4.5

Recycle and Bypass

110

4.6

Chemical Reaction

Stoichiometry 116 4.7

Balances on

Reactive Processes 125 4.8

Combustion

Reactions 142

4.9

Some

Additional Considerations

about Chemical

Processes 4.10

Summary

153

Problems

155

Chapter 5 Single-Phase Systems 187

5.0 InstructionalObjectives 188 5.1

Liquid and

SolidDensities 189 5.2 Ideal

Gases

191

5.3

Equations

of State for

Nonideal Gases

199 5.4

The

Compressibility Factor

Equation

ofState

206

5.5

Summary

213

Problems 214

Chapter 6 Multiphase Systems 237

6.0 InstructionalObjectives

239

6.1

Single-Component Phase Equilibrium 240

6.2

The Gibbs Phase Rule 247

6.3

Gas-Liquid

Systems:

One Condensable Component 249

6.4

Multicomponent Gas-Liquid Systems 255

6.5 Solutions ofSolidsinLiquids

264

6.6

Equilibrium Between Two

Liquid

Phases

₂₇₁ 6.7

Adsorption on

Solid Surfaces 275

6.8

Summary 278 Problems 280

PART 3 ENERGY BALANCES 311

Chapter 7 Energy and Energy Balances 313

7.0 InstructionalObjectives 314

7.1

Forms

of Energy:

The

First

Law

of

Thermodynamics 315

7.2 Kinetic

and

Potential

Energy 317

7.3

Energy Balances on Closed Systems 318