24990060 electrical engineering electric power plant desing

8/21/2019 24990060 Electrical Engineering Electric Power Plant Desing

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TM 5-811-6

TECHNICAL MANUAL

ELECTRIC POWER PLANT DESIGN

H E A D Q U A R T E R S , D E P A R T M E N T O F T H E A R M Y20 JANUARY 1984


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REPRODUCTION AUTHORIZATION/RESTRICTIONS

This manual has been prepared by or for the Government and, except to the extent indicated below, is publicproperty and not subject to copyright.Copyrighted material included in the manual has been used with the knowledge and permission of the proprie-

tors an d is a cknowledged a s such at point of use. Anyone wishing to ma ke further use of any copyrighted ma -terial , by itself an d apar t fr om thi s text, should seek necessary permission directly from the proprietors.Reprints or republicat ions of this ma nua l should include a credit substa ntia lly as follows: D epa rtment of theArmy, USA, Technical Manual TM 5-811-6, Electric Power Plant Design.If the reprint or republication includes copyrighted material , the credit should also state: Anyone wishing tomake further use of copyrighted material , by itself an d apar t fr om thi s text, should seek necessary permissiondirectly from the proprietors.

A/(B blank)


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T E C H N I C A L M A N U A L HEADQUARTERS

DEPARTMENT OF THE ARMY

NO. 5-811-6 WA S H I N G T O N , DC 20 January 1984

ELECTRIC POWER PLANT DESIGN

CHAPTER 1. INTRODUCTION

Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Design philosophy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Design criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Economic considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

C HAPTER 2. S ITE A N D C IVIL FA C IL ITIE S D E S IG NSelection I. Site Selection

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Environment al considerat ions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Water supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Fuel su pply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P hysical cha ra cteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Economic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section II . C ivil Fa cil i t ies, Bu ildings, Safety, a nd SecuritySoils investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Site development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Buildings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C HAPTER 3. STEAM TURBINE POWER PLANT DESIGN

Section I . Typical Pla nts a nd Cy clesIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P lant function and purpose. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Steam power cycle economy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Cogeneration cycles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Selection of cycle steam conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Cycle equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .St eam power plant ar ra ngement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section II . Steam Generators and Auxiliary SystemsSt eam genera tor convention types a nd cha ra cteristics . . . . . . . . . . . . . . . . . . . . . . . .Other st eam genera tor char acterist ics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .St eam genera tor special types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Major au xiliar y syst ems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Minor auxiliary system s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Sect ion I I I . Fuel Ha ndl ing a nd St orage SystemsIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typica l fuel oil stora ge an d ha ndlin g syst em . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Coal ha ndling a nd st orage sys tems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section IV. Ash Handling SystemsIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Description of major components.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section V. Turbines a nd Auxiliary Syst emsTurbin e prime m overs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Generators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Turbine features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Governing and control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Turning gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Lubricat ion systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Extr action feat ures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Inst rument s a nd special tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Section VI. Condenser and Circulat ing Wat er Syst em

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Description of major components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Environment al concerns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section VII. Feedwater SystemFeedwa ter hea ters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Boiler feed pumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Feedwater supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section VIII . Service Wat er a nd C losed Cooling Sy stemsIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Description of major components.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Paragraph

1-11-21-31-4

2-12-22-32-42-52-6

2-72-8

2-9

3-13-23-33-43-53-63-7

3-83-93-103-11

3-12

3-133-143-15

3-163-17

3-183-193-203-213-223-233-243-25

3-263-273-28

3-293-303-31

3-323-33

Page

1-11-11-11-5

2-12-12-12-12-12-1

2-22-2

2-2

3-13-13-13-33-63-63-6

3-93-113-123-12

3-25

3-263-263-27

3-293-30

3-303-323-323-333-333-333-343-34

3-343-353-40

3-403-413-43

3-433-44

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C HAPTER 3. STEAM TURBINE POWER PLANT DESIGN (Continued)

Description of systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Reliability of systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section IX. Water Conditioning Systems

Water conditioning selection.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section X. Compressed Air SystemsIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Description of major components.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Description of systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

C HAPTER 4. GENERATOR AND ELECTRICAL FACILITIES DESIGN

Section I. Typical Voltage Ratings and Systems

Voltages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sta tion service power syetems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sect ion I I . Generators

Genera l types a nd sta nda rds.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Features and acceesories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Excitation systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sect ion I I I . Generator Leads and Switchyard

G enera l . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Generator leads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Switchyard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section IV. Transformers

Genera tor stepup tr an sformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Auxiliary transformers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Un it substa tion tra nsformer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section V. Protective Relays and Metering

Generator, stepup transformer and switchyard relaying . . . . . . . . . . . . . . . . . . . . . . .

Sw itchgear an d MCC protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Instr umenta tion a nd metering. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sect ion VI. Stat ion Service Power Systems

General requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Auxiliary power tr ansformers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4160 volt switchgear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

480 volt unit substations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

480 volt motor control centers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Foundations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Conduit a nd tr ay systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Distr ibution outside the power pla nt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sect ion VII . Emergency Power System

Ba ttery an d charg er . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Emergency ac system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section VIII. Motors

G enera l . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ins ula tion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Horsepower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Grounding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Condu it . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ca ble . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Motor details . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section IX. Communication Systems

Int ra plant communicat ions.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Telephone communications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

C HAPTER 5. GENERAL POWER PLANT FACILITIES DESIGN

Section I . Instruments and Control Systems

G enera l . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Control panels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Automatic control systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Monitoring instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Alar m a nd a nnunciat or systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sect ion I I . Heating, Ventila t ing and Air Condit ioning Systems

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Operations areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Service areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Paragraph

3-34

3-35

3-36

3-37

3-38

3-39

3-40

3-41

4-1

4-2

4-3

4-4

4-5

4-6

4-7

4-8

4-9

4-10

4-11

4-12

4-13

4-14

4-15

4-16

4-17

4-18

4-19

4-20

4-214-22

4-23

4-24

4-25

4-26

4-27

4-28

4-29

4-30

4-31

4-32

4-334-34

P a g e

3-44

3-45

3-45

3-45

3-45

3-46

3-46

3-50

-1

4-1

4-3

4-7

4-8

4-8

4-9

4-13

4-16

4-16

4-17

4-18

4-19

4-19

4-20

4-20

4-20

4-21

4-21

4-21

4-214-21

4-22

4-23

4-23

4-23

4-24

4-24

4-24

4-24

4-24

4-24

4-244-26

5-1

5-2

5-3

5-4

5-5

5-6

5-7

5-8

5-1

5-1

5-5

5-9

5-14

5-14

5-14

5-14

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P a r a g r a p h P a g e

5-155-155-15

5-17

5-175-175-215-215-215-215-21

5-22

5-225-235-24

6-16-16-26-26-26-3

7-17-1

7-27-27-27-27-2

7-37-37-3

8-18-1

8-18-2

P a g e

1-41-53-23-33-53-73-83-93-133-153-16

CHAPTER 5. GENERAL POWER PLANT FACILITIES DESIGN (Continued)Section 111. P ower and Service Piping Systems

5-95-105-11

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P iping design funda menta ls... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Specific system design considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section IV. Thermal Insulat ion and F reeze ProtectionIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-12

5-135-145-155-165-175-185-19

Insulation design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Insula tion ma teria ls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Control of useful heat losses.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Sa fety insula tion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Cold surfa ce insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Economic thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Freeze protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section V. Corrosion Protection5-20Genera l remar ks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section VI. Fire ProtectionIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Design considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

C HAPTER 6.

5-215-225-23Support facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

GA S TURB IN E POWE R PL A N T D E S IGNGeneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Turbin e-genera tor selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

6-16-26-36-46-56-6

Fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P lant ar ran gement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Waste heat recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Eq uipment a nd a uxiliary sy stems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DIESEL ENGINE POWER PLANT DESIGNSection I . Diesel Engine G enerators

Engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Fuel s election . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sect ion I I . B alance of P lan t S ystems

C HAPTER 7.

7-17-2

7-37-47-57-67-7

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Cooling systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Combust ion air inta ke and exhau st sy stems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Fuel stora ge an d ha ndling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Engine room ventilat ion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Section III . Foundations and BuildingGeneral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Engine foundation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7-87-97-10Building . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

COMBINED CYCLE POWER PLANTSSection I . Typical Pla nts a nd C ycles

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P lant deta ils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sect ion I I . General Design Pa rametersBackground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Design approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

R E F E R E N C E S

C HAPTRR 8.

8-18-2

8-38-4

APP E N D IX A :B I B L I O G R A P H Y

LIST OF FiGURES

Figure No.

Figure 1-11-23-13-23-33-43-53-63-73-83-9

Typical Metropolita n Area Loa d Cu rves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Typical Annual Load Dura tion Curve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical St ra ight C ondensing Cycle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Turbine Efficiencies Vs.Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical CondensingCont rolled Ext ra ction Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical Sm al1 2-Un it P ower P lant "A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical Sm al1 2-Un it P ower P lant B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Crit ical Turbine Room Ba y a nd P ower P lant "B Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Fluidized B ed Combustion B oiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Theorectical Air and Combust ion Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Minimum Met al Tempera tur es for Boiler Hea t Recovery Eq uipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


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3-103-113-123-133-143-154-14-2

4-3

4-44-54-64-74-85-16-17-18-1

Tabl e N o.

Ta ble 1-11-21-31-43-13-23-33-43-53-63-73-83-93-103-113-123-133-143-154-14-25-15-25-35-45-55-65-7

Coal H an dling Syst em Dia gra m . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical Coal Handling System for Spreader Stoker Fired Boiler (with bucket elevator). . . . . . . . . . . . . . . . . . .P neuma tic Ash Ha ndling Sy stems-Var iat ions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Types of Circulating Water Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical Compressed Air System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical Arrangement of Air Compressor and Acceesories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .St at ion ConnectionsTwo U nit S ta tion Common B us Arran gement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Station ConnectionsTwo Unit StationUnit ArrangmentGenerator at Distribution Voltage. . . . . . . . . .

Station ConnectionsTwo Unit StationUnit ArrangementDistribution Voltage Higher Than Genera-tion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .One Lone Diagr am -TypicalSt at ion Service P ower Sy stem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical Synchronizing Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical Main and TransferBus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical Ring Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical B reaker a nd a Ha lf Bus.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Economical Thickness of Heat Insula tion (Typical Cu rves) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical Ind oor Sim ple Cycle Ga s Turbine G enerat or PowerP lant .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical Diesel Genera tor P ower P lant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Combined Cycle Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

LIST OF TABLES

G enera l Descript ion of Type of Pla nt. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Diesel Class a nd Opera tional C ha ra cteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P lan t S izes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Deeign Crit eria Req uirements.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Theoretical Stea m Ra tes for Typical St eam Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Fuel Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Indivdua l Bu rner Turndown Ra tios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Em ission Levels Allowa ble, Nat ional Ambient Air Qua lity S ta nda rds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Uncontrolled Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Cha ra cteristics of Cyclones for Pa rticulat e Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Cha ra cteristics of Scrubbers for Pa rticulat e Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Cha ra cterietics of Electrosta tic P recipita tors (ESP ) for Pa rticulat e Control. . . . . . . . . . . . . . . . . . . . . . . . . . . .Cha ra cteristics of Ba ghouses for Pa rticulat e Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Cha racteristics of Flue-Ga s Desulfurization Systems for P art iculate C ontrol. . . . . . . . . . . . . . . . . . . . . . . . . . .Techniques for Nitrogen Oxide Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Condenser Tube Design Velocities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .G eneral G uide for Raw Wat er Treat ment of Boiler Makeup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Int ernal C hemical Treat ment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Effectiveness of Water Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .St an da rd Motor Contr ol Center En closures. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Sug gested Locat ions for Int ra plant Commun ication Sy stem D evices. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .List of Typical Ins tru ment e and Devices for Boiler-Turbine Mechan ical P an el. . . . . . . . . . . . . . . . . . . . . . . . . .List of Typical Instrument and Devices for Common Services Mechanical Panel. . . . . . . . . . . . . . . . . . . . . . .List of Typical Inst ruments a nd Devices for Electrical (Generator a nd Sw itchgear) Pa nel . . . . . . . . . . . . . . . .List of Typical Inst rument an d Devices for Diesel Mecha nical P an el. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Sensing E lements for Contr ols and In stru ments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P iping Codes and S ta nda rds for P ower P lant s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Cha ra cteristics of Therma l Insula tions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-263-28

3-313-383-503-514-24-4

4-54-64-94-104-114-125-226-37-48-3

Page

1-21-31-31-33-43-103-143-173-183-19

3-203-213-223-233-24

3-363-473-483-494-224-255-15-45-65-85-105-165-18

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CHAPTER 1

INTRODUCTION

1-1. Purpose

a. General: This manual provides engineeringdata and criteria for designing electric power plantswhere the s ize and character is t ics of the electr icpower load and the economics of the particular facil-it y justify on-site genera tion. Ma ximum size ofplant considered in this manual is 30,000 kW.b. References: A list of references used in this

manual is contained in Appendix A. Additionally, aBibliography is included identifying sources of ma-terial related to this document.

1-2. Design philosophy

a. General. Electric power plants fall into severalcategories and cla sses depending on t he ty pe ofprime mover. Table 1-1 provides a general descrip-tion of plant type and related capacity require-ments. For purposes of this introduction Table 1-2defines, in more detail, the diesel plant classes andoperational characteristics; additional informationis provided in Chapter 7. No similar categories havebeen developed for gas turbines. Finally, for pur-poses of this manual and to provide a quick scale forthe plants under review here, several categorieshave been developed. These are shown in Table 1-3.

b. Rel i abi l i ty . P lan t re l i ab i l i ty s t andards w i l l be

equivalent to a l-day generation forced outage in 10years w i th equipment qua l ity a nd redundancy se-lected during plant design to conform to this stand-a r d .c. Main tenan ce. Power plant arrangement wil l

permit reasonable access for operation and mainte-nance of equipment. Careful attention will be givento the arrangement of equipment, valves, mechan-ical specialties, and electrical devices so that rotors,tube bundles , inner valves , top works, s tra iners ,contractors, relays, and like items can be maintainedor replaced. Adequate platforms, stairs, handrails,and kickplates will be provided so that operatorsand maintenance personnel can funct ion conven-iently and safely.

d. Fu tu re expansion. The specific site selected forthe power plant and the physical arrangement of theplant equipment, building, and support facili tiessuch as coal and ash handling systems, coal storage,circulat ing water system, trackage, and accessroads will be arranged insofar as practicable to allowfor future expansion.

1-3. Design criteria

a. General r equi r ements. The design w ill providefor a power plant which has the capacity to providethe quantity and type of electric power, steam andcompressed air required. Many of the requirementsdiscussed here are not applicable to each of the plantcategories of Table 1-1. A general overview is pro-vided in Table 1-4.b. El ectr i c power l oads. The following informa-

tion, as applicable, is required for design:(1) Forecast of annual diversif ied peak load to

be served by the project.(2) Typical seasonal and daily load curves and

load duration curves of the load to be served. Ex-ample curves are shown in Figures 1-1 and 1-2.

(3) If the plant is to operate interconnected withthe local utility company, the designer will need in-forma tion such a s capacity , ra tes, metering, and in-terface switchgear requirements.

(4) If the plant is to operate in parallel withexis t ing genera t ion on the ba se, the designer w i l lalso need:

(a) An inventory of major existing generationequipment giving principal characteristics such ascapacities, voltages, steam characteristics, backpressures, and like parameters.

(b) Incremental heat rates of existing boiler-turbine uni ts , diesel generators , and combustionturbine generator units.

(c) Historical operating data for each existinggenerating unit giving energy generated, fuel con-sumption, steam exported, and other related infor-mat ion .

(5) Existing or recommended distribution vol-tage, generator voltage, and interconnecting substa-tion voltages.

(6) If any of the above data as required for per-forming the detailed design is unavailable, the de-signer will develop this data.c. Export s team loads.

(1) General r equi r ements. If the plant will ex-port steam, informa tion similar to tha t required forelectric power, as outlined in subparagraph c above,will be needed by the designer.

(2) Coordination of steam and electric powerloads. To the greatest extent possible, peak, season-al, and daily loads for steam will be coordinated withthe electric power loads according to time of use.

1-1


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Category

Primary

Standby

Tab l e 1- 1. Gene r a l D escr i p t i o n o f T yp e o f P l a n t .

TYPE OF POWER

Capacity No Export Steam

Adequate to meet

requi rement .

Adequate with

mobilization

all p ea ce ti me Purchased electric power to match

electric load.

Continuous duty diesel plant,

Class A diesel.

Straight condensingboilers and

and turbines matched in capacityas units; enough units so plant

without largest unit can carry

emergency load.

prime source to match Purchased electric power.

needs; or alone to supply

emergency electric load and export

steam load in case of primary source Standby diesel plant, Class B

out age. diesel .

Equal to primary source . . . . . . . . . . . . Retired straight condensing plant.

Emergency To supply that part of emergency load Fixed emergency diesel plant,

that cannot be interrupted for mo r e Class C diesel.

than 4 hours. Mobile utilities support equipment.

With Export Steam

Purchased electric power and steam to

match electric load plus supplementary

boiler plant to match export steam load.

Automatic back pressure steam plant plus

automatic packaged firetube boiler to

supplement requirements of export steam

load.

Automatic extraction steam plant boilers

and turbines matched in capacity se units

and enough units installed so that plant

without largest unit can carry emergency

load.

Purchased electric power and steam to

match electric power load plus supple-

mentary boiler plant.

Standby diesel plant with supplementary

boiler plant.

Retired automatic extraction steam plant.

None.

None.

NAVFAC DM3


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TM 5-811-6

Table 1-2. Diesel Class and Operational Characteristics.

Fu1l Load Rating

Capability Expected Operating Hours

Minimum Operating

Class Usage Hours Period -

" "A . . . . . . . . . Continuous . . . . . . . 8,000 . . . . . Yearly . . . . . . . 4,000 hours plus . . . . .

B . . . . . . . . . Standby . . . . . . . . . . 8,000 . . . . . Yearly . . . . . . . 1,000 to 4,000 hours .

c . . . . . . . . . Emergency . . . . . . . . 650 . . . . . Month ly* . . . . . Under 1,000 hours . . . .

*Based on a 30-day month.

U . S . A r m y C o r p s o f E n g i n e e r s

C a t e g o r y

S m a l l

M e d i u m

L a r g e

Table-3. Plant Sizes.

S i z e

o to 2 , 5 0 0 k W

2 , 5 0 0 k W t o 1 0 , 0 0 0 k W

1 0 , 0 0 0 k W t o 3 0 , 0 0 0 k W

U . S . A r m y C o r p s o f E n g i n e e r s

Table-4. Design Criteria Requirements.

C l a s s

( P l a n t C a t e g o r y )

A ( P r i m a r y )

B ( S t a n d b y )

C ( E m e r g e n c y )

E l e c t r i c

P o w e r

L o a d s

A

A

c r i t i c a l

l o a d s o n l y

A = A p p l i c a b l e

N / A=

N o t A p p l i c a b l e

First Ten Years

40,000 hours plus

20,000 to 40,000 hours

Under 10,000 hours

E x p o r t

St earn

L o a d s

A

N / A

N / A

F u e l

S o u r c e

a n d W a t e r S t a c k W a s t e

C o s t Supply E m i s s i o n D i s p o s a l

A A A A

A N / A N / A A

A N / A N / A N /A

C o u r t e s y o f P o p e , E v a n s a n d R o b b i n s ( N o n - C o p y r i g h t e d )

1- 3


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This ty pe of informa tion is par ticula rly importan t ifthe project involves cogeneration with the simul-taneous production of electric power and steam.d. F uel sour ce, an d cost. The type, availability,

and cost of fuel will be determined in the earlystages of design; taking into account regulatory re-quirements that may affect fuel and fuel characteris-tics of the plant.

e. Wat er suppl y. Fresh water is required forthermal cycle makeup and for cooling tower or cool-ing pond makeup where once through water for heatrejection is una va ilable or not usa ble because ofregulatory constraints . Quant i ty o f makeup wil lvary with the type of thermal cycle, amount of con-densate return for any export steam, and the maxi-mum heat rejection from the cycle. This heat rejec-t ion load usually wil l comprise the largest part o fthe makeup and wil l have the least s t r ingent re-quirements for quality .f. St ack em issions. A steam electric power plant

----- Sumner LoadWinter Load

K w

1

will be designed for the type of stack gas cleanupequipment which meets federal, state, and munici-pal emission requirements. For a solid fuel fired boil-er, this will involve an electrostatic precipitator orbag house for particulate, and a scrubber for sulfurcompounds unless fluidized bed combustion or com-pliance coal is employed. If design is based on com-pliance coal, the design will include space and other

required provision for the installat ion of scrubberequipment. B oiler design w ill be specified a s re-quired for NOx control.g. Waste di sposal .

(1) In ternal combust ion plant s. Solid an d liq-uid wastes from a diesel or combustion turbine gen-erating stat ion will be disposed of as follows: Mis-cellaneous oily wastes from storage tank areas andsumps will be directed to an AP I separa tor. Supple-mentary treating can be utilized if necessary to meetthe applicable requirements for waste water dis-charge. For plants of size less than 1,000 kW, liquid

.U R B A N

[NDUSTRIAL TRACTION

LOAD LOAD

1 2 6 1 2 6 1 2 6 1 2 6 1 2 6 1 2 6 1 2AM PM AM PM AM PM

FROM POWER STATION ENG INE ERI NG AND ECONOMY BY SROTZKI AND LOP AT.

COPYRIGHT BY THE MC GRAW-HILL BOOK COMPANY, INC. USED WITH THEPERMISSION OF MC GRAW-HILL BOOK COMPANY.

Fi gure 1-1. Typical m etr opoli tan ar ea load curv es.

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TM 5-811-6

oily wastes will be accumulated in sumps or smalltanks for removal. Residues from filters and centri-fuges will be similarly handled.

(2) Steam electri c stat ion s. For s team electr icgenerating stations util izing solid fuel, both solidand liquid wastes will be handled and disposed of inan environmentally acceptable manner. The wastescan be categorized generally as follows:

(a) Solid wa stes. These include both bottom

ash and fly ash from boilers.(b) L iqu id wastes. These include boiler blow-

down, cooling tow er blowdow n, a cid a nd caust icwater treating wastes, coal pile runoff , and variouscontaminated wastes from chemical storage areas,sani tary sewage and yard areas .h. Other envi r onmental consid er ati ons. Other en-

vironmental considerations include noise controland aesthetic treatment of the project. The final lo-cation of the project within the site area will be re-viewed in rela t ion to i ts proximity to hospi ta l an doffice areas and the civilian neighborhood, if appli-cable. Also, the general architectural design will be

reviewed in terms of coordination and blending with

I

the style of surrounding buildings. Any anticipatednoise or aesthetics problem will be resolved prior tothe time that final site selection is approved.

1-4. Economic considerations

a. The selection of one particular type of designfor a given application, when two or more types ofdesign are known to be feasible, will be based on theresults of an economic study in accordance with the

requirements of DOD 4270.1-M and the NationalEnergy Conservation Policy Act (Public Law95-619,9 NOV 1978).b. St a nda rds for economic s tudies are conta ined

in AR 11-28 and AFR 178-1, respectively. Addi-tional standards for design applications dealingwit h energ y/fuel consum ing elements of a fa cili tyare contained in the US Code of Federal Regula-tions, 20 CFR 436A. Clarification of the basic stand-ards and guidelines for a particular a pplicat ion a ndsupplementary standards which may be required forspecial cases may be obtained through normal chan-nels from HQDA (DAEN-ECE-D), WASH DC

20314.

I0 1000 2000 3000 4000 5000 6000 7000 8000 8760-

U.S. Army Corps of

Fi gure 1-2.

HOURS

Engineers

Typical annual load durat ion cur ve.

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CHAPTER 2

SITE AND CIVIL FACILITIES DESIGN

Section 1. SITE SELECTION

2-1. Introduction

Since the selection of a plant si te has a significantinfluence on the design, construction and operatingcosts of a power plant , ea ch potentia l pla nt si te wil lbe evaluated to determine which is the mosteconomically feasible for the type of power plant be-ing considered.

2-2. Environmental considerations

a. Rul es and r egul ati ons. All power plant design,regardless of the ty pe of power plant , must be in ac-cordance with the rules and regulat ions which have

been establ ished by Federal , state and local govern-mental bodies.

b. Extr aordi nar y design featu res. To meet var-ious environmental regulations, it is often necessaryto uti l ize design features that wil l greatly increasethe cost of the power plant without increasing its ef-ficiency. For example, the cost of the pollution con-trol equipment that will be required for each site un-der consideration is one such item which must becarefully evaluated.

2-3. Water supply

a. General r equi r ement s. Wa ter supply w ill beadequate to meet present and future plant require-ments. The supply maybe available from a local mu-nicipal or privately owned system, or it may be nec-essary to utilize surface or subsurface sources.b. Qual i t y. Water qual i ty and type of treatment

required will be compatible with the type of powerplant to be built.c. Water r igh ts. I f water rights are required, i t wi l l

be necessary to insure that an agreement for waterrights provides sufficient quanti ty for present andfuture use.d. Wat er w ell s. I f the makeup to the closed sys-

tem is from water wells , a study to determine watertab le information and wel l drawdown wil l be re-quired. If this information is not avai lable, test wellstudies must be made.

e. Once-th r ough system . I f the plant has a oncethrough cooling system, the following will be deter-mined:

(1) The limitations established by the appro-pria te regulat ory bodies w hich m ust be met to ob-

tain a permit required to discharge heated water tothe source.

(2) Maximum allowable temperature rise per-missible as compared to system design parameters.If system design temperature rise exceeds permissi-ble rise, a supplemental cooling system (coolingtower or spray pond) must be incorporated into thedesign.

(3) Maximum allowable temperature for riveror lake after mixing of cooling system effluent withsource. I f mixed temperature is higher than al low-able temperature, a supplemental cooling system

must be added. It is possible to meet the conditionsof (2) above and not meet the conditions in this sub-p a r a g r a p h .

(4) I f extensive or repetitive dredging of wat-erway will be necessary for plant operations.

(5) The historical maximum and minimumwater level and flow readings. Check to see that ade-quate water supply is avai lab le a t minimum f lowand if site will flood at high level.

2-4. Fuel supply

Site selection will take into consideration fuel stor-age and the ingress and egress of fuel delivery equip-

ment.

2-5. Physical characteristics

Selection of the site will be based on the availabilityof usable land for the plant , including yard s truc-tures, fuel handling facilities, and any future expan-sion. Other considerations that will be taken into ac-count in site selection are:

-Soil information.-Site drainage.- Wind data.-Seismic zone.-Ingress and egress.

For economic purposes and operational efficiency,the plant site will be located as close to the load cen-ter as environmental conditions permit.

2-6. Economics

Where the choice of several sites exists, the final se-lection will be based on economics and engineerings tudies .

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Section Il. CIVIL FACILITIES, BUILDINGS, SAFETY, AND SECURITY

2-7. Soils investigation

An analysis of existing soils conditions will be madeto determine the proper type of foundation. Soilsdata wil l include elevat ion of each boring , watertable level, description of soil strata including thegroup symbol based on the Unified Soil Classifica-

tion System, and penetration data (blow count). Thesoils report will include recommendations as to typeof foundations for various purposes; excavation, de-watering and fil l procedures; and suitability of on-site material for fill and earthen dikes including dataon soft and organic materials, rock and other perti-nent information as applicable.

2-8. Site development

a. Grad in g and dr ainage.

(1) Basic crit eri a. Determinat ion of f inal grad-ing and drainage scheme for a new power plant willbe based on a number of considerations including

size of property in relationship to the size of plantfacilities, desirable location on site, and plant accessbased on topogra phy. I f the pow er pla nt is pa rt o fan overall complex, the grading and drainage will becompatible and integrated with the rest of the com-plex. To minimize cut and fill, plant facilities will belocated on high ground and storm water drainagewill be directed away from the plant. Assuming onsite soils are suitable, grading should be based onbalanced cut and fill volume to avoid hauling of ex-cess fill material to offsite disposal and replacementwith expensive new material.

(2) Drainage. Storm water drainage will be

evaluated based on rainfall intensities, runoff char-acteristics of soil, facilities for receiving stormwater discharge, and local regulations. Storm waterdrains or systems will not be integrated with sani-tary drains and other contaminated water drainagesys tems.

(3) Er osion pr eventi on. All graded areas wil l bestabilized to control erosion by designing shallowslopes to the greatest extent possible and by meansof soil stabilization such as seeding, sod, stone, rip-rap and retaining walls .b. Roadways.

(1)Basic roadw ay r equi rements .

Layout o fplant roadways will be based on volume and type oftraffic, speed, and traffic patterns. Type of traffic orvehicle functions for power plants can be catego-rized as follows:

-Passenger cars for plant personnel.-Passenger cars for visitors.-Trucks for maintenance material deliveries.-Trucks for fuel supply.

-Trucks for removal of ash, sludge and otherwaste mater ia ls .

(2) Roadway mater ia l and w idth . Aside fromtemporary construction roads, the last two catego-ries described above will govern most roadway de-sign, particularly if the plant is coal f ired. Roadwaymaterial and th ickness wil l be based on economicevaluat ions of feasible a lternat ives. Vehicular park-ing for plant personnel and visitors will be located inareas that will not interfere with the safe operationof the plant. Turning radii will be adequate to han-dle all vehicle categories. Refer to TM 5-803-5/N AVP AC P -960/AFM 88-43; TM 5-818-2/AFM 88-6, C ha p. 4; TM 5-822-2/AFM 88-7, C ha p.7; TM 5-822-4/AFM 88-7, C h a p. 4 ; TM5-822 -5/AFM 88-7, C ha p. 3; TM 5-822-6/AFM88-7, Cha p. 1; TM 5-822-7/AFM 88-6, Ch a p. 8; a ndTM 5-822-8.c. Railroads. I f a railroad spur is selected to han-

dle fuel supplies a nd m at erial a nd equipment deliv-eries during construction or plant expansion, the de-sign wil l be in a ccordance with America n Ra ilwa yEngineering Associat ion standards. I f coal is thefuel, spur layout will accommodate coal handling fa-cilities including a storage track for empty cars. I fliquid fuel is to be handled, unloading pumps andsteam connections for tank car heaters may be re-quired in frigid climates.

2-9. Buildings

a. Size and ar ra ngement.

(1) Steam plan t. Main building size and ar-

rangement depend on the selected plant equipmentand faci l i t ies including whether steam generatorsare indoor or outdoor type; coal bunker or silo ar-rangement; source of cooling water supply relativeto the plant ; the re lat ionship of the switchyard toth e pla nt; provisions for future expansion; a nd ,aesthetic and environmental considerations. Gener-ally, the main building will consist of a turbine baywith traveling crane; an auxiliary bay for feedwaterheaters, pumps, and switchgear; a steam generatorbay (or firing aisle for semi-outdoor units); and gen-eral spaces as may be required for machine shop,

locker room, la bora tory a nd office fa cilities. Thegeneral spaces will be located in an area that will notinterfere with future plant expansion and isolatedfrom main plant facilities to control noise. For verymild climates the turbine generator sets and steamgenerators may be outdoor type (in a weather pro-tected, walk-in enclosure) although this arrange-ment presents special maintenance problems. If in-corporated, the elevator will have access to the high-

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TM 5-811-6

est operating level of the steam generator (drum lev-els).

(2) Di esel pla nt . The requirements for a build-ing housing a diesel generator plant are the same asfor a steam turbine plant except that a steam gener-ator bay is not required.b. Architectural treatment.

(1) The architectural treatment will be de-veloped to harmonize with the site conditions, both

natural and manmade. Depending on location, theenvironmental compatibility y may be the determin-ing factor. In other cases the climate or user prefer-ence, tempered with aesthetic and economic factors,wil l dic ta te archi tectural treatment . Cl imate is acontrolling factor in whether or not a total or partialclosure is selected. Semi-outdoor construction withthe bulk of the steam generator not enclosed in aboiler room is an acceptable design.

(2) For special circumstances, such as areaswhere extended periods of very high humidity, fre-quently combined with desert conditions giving riseto heavy dust and sand blasting action, indoor con-

struction with pressurized ventilation will be re-quired not only for the main building but also, gen-erally , for the switchyard. Gas enclosed switchyardinstallations may be considered for such circum-stances in lieu of that required above.

(3) Cont rol rooms, offices, locker r ooms, a ndsome out-buildings will be enclosed regar dless of en-

closure selected for main building. Circulating waterpumps may be installed in the open, except in themost severe climates. For semi-outdoor or outdoorstations, enclosures for switchgear and motor con-trols for the auxiliary power system will be enclosedin manufacturer supplied walk-in metal housings or

site fabricated closures.c. Stru ctur al design.

(1) Building framing and turbine pedestals.Thermal stations will be designed utilizing conven-t ional s tructural s teel for the main power s ta t ionbuilding and support of boiler. The pedestal for sup-

port ing the turbine generator (and turbine drivenboiler feed pump if utilized) will be of reinforced con-crete. Reinforced concrete on masonry constructionmay be used for the building framing (not for boilerframing); special concrete inserts or other provisionmust be made in such event for support of piping,trays and conduits. An economic evaluation will bemade of these al ternatives.

(2) Exteri or w all s. The exterior walls of mostthermal power stations are constructed of insulatedmetal panels. However, concrete blocks, bricks, orother material may be used depending on the aes-thetics and economics of the design.

(3) In ter i or wal ls . Concrete masonry blocks willbe used for interior walls; however, some specialized

areas, such as for the control room enclosure and foroffices, may utilize factory fabricated metal walls,fixed or moveable according to the application.

(4) Roof d ecks. Main building roof decks will beconstructed of reinforced concrete or ribbed metaldeck with built-up multi-ply roofing to provide wat-erproofing. Roofs will be sloped a minim um of 1/4,-inch per foot for drainage.

(5) Floors. Except where grating or checkered

plate is required for access or ventilation, all floorswill be designed for reinforced concrete with a non-slip finish.

(6) L ive loads. Buildings, s tructures and al lportions thereof will be designed and constructed tosupport all l ive and dead loads without exceedingthe a l lowa ble s tresses of the selected ma teria ls inthe structural members and connections. Typicallive loads for power plant floors are as follows:

(a) Turbine generator floor 500 psf(b) Basement and operating floors except

turbine generator floor 200 psf(c) Mezzanine, deaerator, and

miscellaneous operating floors 200 psf(d) Offices, laboratories, instrument

shops, and other lightly loaded areas 100 psfLive loa ds for a ctual design w ill be carefully re-viewed for a ny special condi t ions and actua l loa dsapplicable.

(7) Oth er l oads. In addition to the l ive and deadloads, the following loadings will be provided for:

(a) Win d loadin g. Building will be designed toresist the horizontal wind pressure available for thesite on all surfaces exposed to the wind.

(b) Seismi c loadin g. Buildings and otherstructures will be designed to resist seismic loading

in accordance with the zone in which the building islocated.

(c) Equipm ent load ing. Equipment loads a refurnished by the various manufacturers of eachequipment item. In addition to equipment deadloads, impact loads, short circuit forces for genera-tors, and other pertinent special loads prescribed bythe equipment function or requirements will be in-cluded.d. Foundat ion design.

(1) Foundations will be designed to safely sup-port all structures, considering type of foundationand allowable bearing pressures. The two most com-mon types of foundat ions are spread foot ings andpile type foundations, although raft type of otherspecial approaches may be utilized for unusual cir-cumstances.

(2) Pile type foundations require reinforcedconcrete pile caps and a system of reinforced con-crete beams to tie the caps together. Pile load capa-bilities may be developed either in friction or point

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TM 5-811-6

bearing. The allowable load on piles will be deter-mined by an approved formula or by a load test .Piles can be timber, concrete, rolled structural steelshape, steel pipe, or steel pipe concrete filled.

(3) Design of the reinforced concrete turbinegenerator or diesel set foundat ion, both mat andpedestal, will be such that the foundation is isolatedfrom the main building foundations and structuresby expansion joint material placed around its perim-eter. The design will also insure that the resonanceof the foundation at operating speed is avoided inorder to prevent cracking of th e founda tion an ddamage to machines caused by resonant vibration.The foundation will be designed on the basis of de-flection. The limits of deflection will be selected toavoid values of na tura l frequency by a t least 30 per-cent above or 30 percent below operating speed.

(4) Vibration mounts or f loating f loor foun-dations where equipment or equipment foundationinertia blocks are separated from the main buildingfloor by springs or precompressed ma teria l w ill gen-

erally not be used in power plants except for ventila-tion fans and other building service equipment. Inthese circumstances where such inertia blocks areconsidered necessary for equipment not normally somounted, written justif ication will be included inthe project design analysis supporting such a neces-si ty .

(5) The location of turbine generators, diesel en-gine sets, boiler feed pumps, draft fans, compres-sors , and other high speed rotat ing equipment onelevated floors will be avoided because of the diffi-culty or impossibili ty of isolating equipment foun-dations from the building structure.

2-10. Safety.

a. Int r oduct ion. The safety features described inthe following paragraphs will be incorporated intothe power plant design to ass is t in maintaining ahigh level of personnel safety.b. Desi gn safety features. In designing a power

plant, the following general recommendations onsafety will be given attention:

(1) Equipment wil l be arranged with adequatea ccess space for operat ion a nd for ma intena nce.Wherever possible, auxiliary equipment will be ar-ranged for maintenance handling by the main tur-

bine room crane. Where this is not feasible, mono-rails, wheeled trucks, or portable A-frames shouldbe provided if disassembly of heavy pieces is re-quired for maintenance.

(2) Safety guards will be provided on movingparts of all equipment.

(3) All valves, specialties, and devices needingmanipulation by operators will be accessible with-out ladders, and preferably without using chain

w heels. This can be achieved by car eful piping de-sign, but some access platforms or remote mechani-cal operators may be necessary.

(4) Impact type handwheels will be used forhigh pressure valves and all large valves.

(5) Valve centers will be mounted approximate-ly 7 feet above f loors a nd pla t forms so tha t r is ingstems and bottom rims of handwheels will not be a

h a z a r d .(6) Stairs with conventional riser-tread propor-tions will be used. Vertical ladders, installed only asa las t resort , must have a safety cage i f required by .the Occupational Safety and Health Act (OSHA).

(7) All floors, gratings and checkered plates willhave non-slip surfaces.

(8) No platform or walkway will be less than 3 feet wide.

(9) Toe plates, fitted closely to the edge of allfloor openings, platforms and stairways, will be pro-vided in all cases.

(10) Adequate piping and equipment drains to

waste will be provided.(11) All floors subject to washdown or leaks willbe sloped to floor drains.

(12) All areas subject to lube oil or chemicalspills will be provided with curbs and drains,

(13) If plant is of semi-outdoor or outdoor con-struct ion in a c limat e subject to f reezing w eath er ,weather protection will be provided for criticaloperating and maintenance areas such as the f ir ingaisle, boiler steam drum ends and soot blower loca-t ions.

(14) Adequate illumination will be providedthroughout the plant . Il luminat ion w ill comply w ith

requirements of the Illuminating Engineers Society(IES) Lighting Handbook, as implemented by DOD4270.1-M.

(15) Comfort air conditioning will be providedthroughout control rooms, laboratories, offices andsimilar spaces where operat ing and maintenancepersonnel spend considerable time.

(16) Mechanical supply and exhaust ventilationwill be provided for all of the power plant equipmentareas to alleviate operator fatigue and prevent accu-mulation of fumes and dust. Supply will be ductedto direct air to the lowest level of the power plantand to areas with large heat release such as the tur-

bine or engine room and the boiler feed pump area.Evaporative cooling will be considered in low hu-midi ty areas . Venti la t ion a ir wi l l be f i l tered andheated in the winter also, system air f low capacityshould be capable of being reduced in the winter.Battery room will have separate exhaust fans to re-move hydrogen emitted by batteries as covered inTM 5-811-2/AFM 88-9, C ha p. 2.

(17) Noise level w ill be reduced t o at least th e

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recommended maximum levels of OSHA. Use of fansilencers, compressor silencers, mufflers on internalcombustion engines, and acoustical material is re-quired as di scu ss ed i n TM 5-805-4/AFM88-37/NAVF AC D M-3.1O a nd TM 5-805-9/AFM88-20/NAVFAC DM -3.14. Consid era t ion sh ould begiven to locating forced draft fans in acousticallytreat ed fan rooms since they are usually the la rgest

noise source in a power plant. Control valves will bedesigned to limit noise emissions.(18) A central vacuum cleaning system should

be considered to permit easy maintenance of plant.

(19) Color schemes will be psychologically rest-ful except where danger must be highl ighted withspecial bright primary colors.

(20) Each equipment item will be clearly la-belled in block letters identifying it both by equipment item number and name. A complete, coordi-nated system of pipe markers will be used for identi-fication of each separate cycle and power plant serv-ice system. All switches, controls, and devices on allcontrol panels will be labelled using the identicalnames shown on equipment or remote devices beingcontrolled.

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CHAPTER 3

STEAM TURBINE POWER PLANT DESIGN

Section 1. TYPICAL PLANTS AND CYCLES

3-1. Introduction

a. Def ini t ion. The cycle of a steam power plant isthe group of interconnected major equipment com-ponents selected for optimum thermodynamic char-acteristics, including pressure, temperatures and ca-paci t ies , and integrated into a pract ical arrange-ment to serve the electrical (and sometimes by-prod-uct steam) requirements of a particular project. Se-lection of the optimum cycle depends upon plantsize, cost of money, fuel costs, non-fuel operatingcosts, and maintenance costs.b. Steam condi ti ons. Typical cycles for the prob-

able size and type of steam power plants at Army es-tablishments will be supplied by superheated steamgenerated at pressures and temperatures between600 psig (at 750 to 850F) and 1450 psig (at 850 to950 F). Reheat is never offered for turbine genera-tors of less than 50 MW and, hence, is not applicablein th is manual .c. Steam tur bin e pr im e mover s. The steam tur-

bine prime mover, for rated capacity limits of 5000kW to 30,000 kW, will be a multi-stage, multi-valveunit, either back pressure or condensing. Smallerturbines, especially under 1000 kW rated capacity,

may be single stage units because of lower first costand s implic i ty . Single s tage turbines , ei ther backpressure or condensing, are not equipped with ex-traction openings.

d. Back pr essur e tu r bi nes. Back pressure turbineunits usually exhaust at pressures between 250 psigand 15 psig with one or two controlled or uncon-trolled extractions. However, there is a significantprice difference between controlled and uncontrolledextraction turbines, the former being more expen-sive. Controlled extraction is normally appliedwhere the bleed steam is exported to process or dis-tr ict heat users.

e. Condensin g tu r bin es. Condensing units ex-haust at pressures between 1 inch of mercury abso-lute (Hga) and 5 inches Hga, wi th up to two con-trolled, or up to five uncontrolled, extractions.

3-2. Plant function and purpose

a. Integrat ion into general planning. G e n e r a lplant design parameters wil l be in accordance withoverall criteria established in the feasibility study or

planning criteria on which the technical and econom-ic feasibility is based. The sizes and characteristicsof the loads to be supplied by the power plant, in-cluding peak loads, load factors, allowances for fu-ture growth, the requirements for rel iab i l i ty , andthe criteria for fuel, energy, and general economy,will be determined or verif ied by the designer andapproved by appropriate authority in advance of thefinal design for the project.

b. Sel ection of cycl e condi ti ons. Choice of steamconditions, types and sizes of steam generators andturbine prime movers, and extraction pressures de-pend on the function or purpose for which the plantis intended. G eneral ly , these basic cr i ter ia shouldhave already been established in the technical andeconomic feasibility studies, but if all such criteriahave not been so established, the designer will selectthe parameters to suit the intended use.c. Coener ati on pl ant s. Back pressure and con-

tr olled extra ction/condens ing cycles a re a tt ra ctiveand applicable to a cogeneration plant, which is de-f ined a s a power plant simultaneously supplyingeither electric power or mechanical energy and heatenergy (para. 3-4).

d. Si mpl e cond ensin g cycl es. Str aight condensingcycles, or condensing units with uncontrolled ex-tractions are applicable to plants or situationswhere security or isolation from public utility powersupply is more important than lowest power cost .Because of their higher heat ra tes and operat ingcosts per unit output, it is not likely that simple con-densing cycles will be economically justified for amilitary power plant application as compared withthat associated with public utility purchased powercosts. A schematic diagram of a simple condensingcycle is shown on Figure 3-1.

3-3.Steam power cycle economy

a. In t roduc t ion. Maximum overall eff iciency andeconomy of a steam power cycle are the principal de-sign criteria for plant selection and design. In gener-al, better eff iciency, or lower heat rate, is accom-panied by higher costs for initial investment, opera-tion and maintenance. However, more efficientcycles are more complex and may be less reliable perunit of capacity or investment cost than simpler and

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TM 5-611-6

NAVF AC DM3

Fi gur e 3-1. Typical str aigh t cond ensin g cycle.

less efficient cycles. Efficiency characterist ics canbe listed as follows:

(1) Higher steam pressures and temperaturescontribute to better, or lower, heat rates.

(2) For condensing cycles, lower back pressuresincrease efficiency except that for each part icularturbine unit there is a crossover point where lower-ing back pressure further will commence to decreaseefficiency because the incremental exhaust loss ef-fect is greater than the incremental increase in avail-able energy.

(3) The use of stage or regenerative feedwatercycles improves heat rates, with greater improve-ment corresponding to larger numbers of such heat-ers. In a regenerative cycle, there is also a thermody-namic crossover point where lowering of an extrac-tion pressure causes less steam to f low through theextraction piping to the feedwat er heat ers, reducingthe feedwater temperature. There is also a l imit toth e number of sta ges of extra ction/feedwa ter hea t-ing which may be economically added to the cycle.This occurs when additional cycle efficiency no long-er justifies the increased capital cost.

(4) La rger tur bine generat or units a re generallymore efficient that smaller units.

(5) Multi-sta ge a nd multi-va lve turbines a remore economical than single stage or single valvemachines.

(6) Steam generators of more elaborate design,or with heat saving accessory equipment are moreefficient.b. Heat rate uni ts and d efini t ions. The economy

or efficiency of a steam power plant cycle is ex-

3-2

pressed in terms of heat rate, which is total thermalinput to the cycle divided by the electrical output ofthe un its. U nits a re B tu/kWh.

(1) Conversion to cycle efficiency, as the ratio ofoutput to input energy, may be made by dividingthe heat content of one kWh, equivalent to 3412.14Bt u by t he heat ra te, a s defined. Efficiencies are sel-dom used to express overall plant or cycle perform-ance, although efficiencies of individual compo-nents, such as pumps or steam genera tors, are com-monly used.

(2) P ower cycle economy for pa rt icula r pla nt s orstations is sometimes expressed in terms of poundsof steam per kilowatt hour, but such a parameter isnot readily comparable to other plants or cycles andomits steam generator efficiency.

(3) For mechanical drive turbines, heat ratesare sometimes expressed in Btu per hp-hour, exclud-ing losses for the driven machine. One horsepowerhour is equivalent to 2544.43 Btu.c. H eat r ate appl icati ons. In relation to steam

power plant cycles, several types or definit ions ofheat rates are used:

(1) The turbine heat rate for a regenerative tur-bine is defined as the heat consumption of the tur-bine in terms of heat energy in steam supplied bythe steam generator, minus the heat in the feedwa-ter as warmed by turbine extract ion , divided bythe e lectrical output at the generator terminals .This definit ion includes mechanical and electricallosses o f the generator and turbine auxil iary sys-tems, but excludes boiler inefficiencies and pumpinglosses and loads. The turbine heat rate is useful for


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performing engineering and economic comparisonsof various turbine designs. Table 3-1 provides theo-retical turbine steam rates for typical steam thrott le

conditions. Actua l stea m ra tes ar e obtained by di-

viding the theoretical steam rate by the turbine effi-ciency. Typical turbine efficiencies are provided onFigure 3-2.

ASR =

where: ASR = a ctua l stea m ra te (lb/kWh)TSR = th eoretical stea m r at e (l/kWh)

n t = turbine efficiencyTurbine heat rate can be obtained by multiplyingthe actual steam rate by the enthalpy change acrossthe turbine (thrott le enthalpy - extraction or ex-haust enthalpy).

C t = ASR(hl h 2)where = tur bine heat r a te (B tu/kWh)

ASR = actua l steam ra te lb/kWh)h 1 = throt t le entha lpyh 1 = extraction or exhaust enth alpy

TSR

FROM STANDARD HANDBOOK FOR MECHANICAL

ENGINEERS BY MARKS. COPYRIGHT 1967,

MCGRAW-HILL BOOK CO. USED WITH THE

PERMISSION OF MCGRAW- HILL BOOK COMPANY.

Fi gur e 3-2. Tur bin e effi ciencies vs. capacity.

(2) Plant heat rates include inefficiencies andlosses external to the turbine generator, principallyth e inefficiencies of th e stea m generat or a nd pipingsystems; cycle auxiliary losses inherent in power re-quired for pumps and fans; and related energy usessuch as for soot blowing, air compression, and simi-lar services.

(3) Both turbine and plant heat rates, as above,are usually based on calculations of cycle perform-ance at specif ied steady state loads and well def ined,optimum operating conditions. Such heat rates areseldom achieved in practice except under controlledor test conditions.

(4) P lant operat ing heat ra tes ar e long termaverage actual heat rates and include other suchlosses a nd energy uses a s n on-cycle auxiliaries,

plan t l ighting, a ir conditioning a nd hea ting, generalwater supply, startup and shutdown losses, fuel de-terioration losses, and related items. The gradualand inevitable deterioration of equipment, and fai l-ure to operate at optimum conditions, are reflectedin p lant operat ing heat ra te data .d. Pl ant economy calcul ati ons. Calculations, esti-

mates, and predictions of steam plant performancewill allow for all normal and expected losses and

loads and should, therefore, reflect predictions ofmonthly or an nual net opera ting heat ra tes andcosts. Electric and district heating distributionlosses are not usually charged to the power plantbut should be recognized and allowed for in capacityand cost analyses. The designer is required to devel-op and optimize a cycle heat balance during the con-ceptual or preliminary design phase of the project.The heat balance depicts, on a simplified flow dia-gra m of the cycle, all significant fluid mass flowrates, f luid pressures and temperatures, f luid en-thalpies, electric power output, and calculated cycleheat rates based on these factors. A heat balance isusually developed for various increments of plantloa d (i.e., 25%, 50%, 75%, 100% a nd VWO (va lveswide open)). Computer programs have been devel-oped which can quickly optimize a particular cycleheat rate using i terative heat balance calculations.Use of such a program should be considered.e. Cogenerat i on per form ance. There is no gener-

ally accepted method of defining the energy effi-ciency or heat rates of cogeneration cycles. Variousmethods are used, and any rational method is valid.The difference in value (per Btu) between prime en-ergy (i.e., electric power) and secondary or low level

energy (heating steam) should be recognized. Referto discussion of cogeneration cycles below.

3-4. Cogeneration cycles

a. Def ini t ion. In steam power plant practice, co-generation normally describes an arrangementwh ereby high pressure stea m is passed th rough aturbine prime mover to produce electrical power,and thence from the turbine exhaust (or extraction)opening to a lower pressure steam (or heat) distribu-t ion system for general heating, refrigeration, orprocess use.

b. Comm on medium . Steam power cycles are par-

ticularly applicable to cogeneration situations be-cause the actual cycle medium, steam, is also a con-venient medium for area distribution of heat.

(1) The choice of the steam distribution pres-sure will be a balance between the costs of distribu-tion which are sl ightly lower at high pressure, andthe gain in electrical power output by selection of alower turbine exhaust or extraction pressure.

(2) Often the early selection of a relatively low

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steam distribution pressure is easily a ccommoda tedin the design of distribution and utilization systems,whereas t he has ty selection of a relatively highsteam distribution pressure may not be recognizedas a distinct economic penalty on the steam powerplant cycle.

(3) Hot water heat distribution may also be ap-plicable as a district heating medium with the hot

water being cooled in the util ization equipment andreturned to the power plant for reheating in a heatexchange with exhaust (or extraction) steam.c. Relat i ve economy. When the exhaust (or ex-

t ract ion) steam from a cogenerat ion plant can beutilized for heating, refrigeration, or process pur-poses in reasonable phase with the required electricpower load, there is a marked economy of fuel ener-gy because the major condensing loss of the conven-tional steam power plant (Rankine) cycle is avoided.If a good balance can be attained, up to 75 percent ofthe total fuel energy can be utilized as comparedwith about 40 percent for the best and largest Ran-kine cycle plants and about 25 to 30 percent forsmall Rankine cycle systems.d. Cycl e types. The two major steam power cogen-

eration cycles, which may be combined in the sameplant or establishment, are:

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(1) Back pr essu r e cycl e. In this type of plant,the entire flow to the turbine is exhausted (or ex-tr a cted) for hea ting st eam use. This cycle is themore effective for heat economy and for relat ivelylower cost of turbine equipment, because the primemover is smaller and simpler and requires no con-denser and circulating water system. Back pressureturbine generators are limited in electrical output by

the amount of exhaust steam required by the heatload and are of ten governed by the exhaust steamload. They, therefore, usually operate in electricalparallel with other generators.

(2) Extraction-condensing cycles. Where theelectrical demand does not correspond to the heatdemand, or where the electrical load must be carriedat times of very low (or zero) heat demand, then con-densing-controlled extraction steam turbine primemovers as shown in Figure 3-3 may be applicable.Such a turbine is ar ra nged to carry a specified elec-trical capacity either by a simple condensing cycleor a combination of extraction and condensing.While very flexible, the extraction machine is rela-t ively complicated, requires complete condensingand heat rejection equipment, and must always passa critical minimum flow of steam to its condenser tocool the low pressure buckets.

NAVFAC DM3 Fi gur e 3-3. Typical condensing-contr olled extin ction cycle.

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e. Cr it eri a f or cogenerati on. For minimum eco-nomic feasibility, cogeneration cycles will meet thefollowing criteria:

(1) L oad bal ance. There should be a reasonablybalanced relationship between the peak and normalrequirements for electric power and heat. Thepeak/norma l ra tio sh ould not exceed 2:1.

(2) L oad coincid ence. There should be a fairly

high coincidence, not less th a n 70%, of tim e an dquantity demands for electrical power and heat.

(3) Size. While there is no absolute minimumsize of steam power plant which can be built for co-generation, a conventional steam (cogeneration)plant will be practical and economical only abovesome minimum size or capacity, below which othertypes of cogeneration, diesel or gas turbine becomemore economical and convenient.

(4) Distr ibut ion medium . Any cogenerationplant will be more effective and economical if theheat dist r ibut ion medium is chosen at the lowestpossible steam pressure or lowest possible hot watertemperature. The power energy delivered by the tur-bine is highest when the exhaust steam pressure islowest. Substantial cycle improvement can be madeby select ing a n exha ust steam pressure of 40 psigrather than 125 psig, for example. Hot water heatdistribution will also be considered where practicalor convenient , because hot w a ter t empera tures o f200 to 240 F can be delivered with exhaust steampressure as low as 20 to 50 psig. The balance be-tween distr ibution system and heat exchangercosts, and power cycle effectiveness will be opti-mized.

3-5. Selection of cycle steam conditions

a. Ba la nced costs and economy. For a new or iso-lated plant , the choice of init ial steam condit ionsshould be a balance between enhanced operat ingeconomy at higher pressures and temperatures, andgenerally lower first costs and less difficult opera-tion at lower pressures and temperatures. Realisticprojections of future fuel costs may tend to justifyhigher pressures and temperatures, but such factorsas lower avai labi l i ty y , h igher maintenance costs ,more diff icult operation, and more elaborate watertreatment will also be considered.

b. Extension of existing plant. Where a newsteam power plant is to be installed near an existingsteam power or steam generation plant, careful con-sideration will be given to extending or parallelingthe existing initial steam generating conditions. I fexisting steam generators are simply not usable inthe new plant cycle, i t may be appropriate to retirethem or to re tain them for emergency or standbyservice only. If boilers are retained for standby serv-

ice only, steps will be taken in the project design for

protection against internal corrosion.c. Special consid er ati ons. Where the special cir-

cumstances of the establ ishment to be served aresignificant factors in power cycle selection, the fol-lowing considerations ma y a pply:

(1) El ectr ical isolat i on. Where the proposedplant is not to be interconnected with any local elec-tric utility service, the selection of a simpler, lower

pressure plant may be indicated for easier operationand better reliability y.

(2) Geogra phi c isolat ion. Plants to be instal ledat great distances from sources of spare parts, main-tenance services, and operating supplies may re-quire special consideration of simplified cycles, re-dundant capacity and equipment, and highest prac-tical reliability. Special maintenance tools and facil-ities may be required, the cost of which would be af-fected by the basic cycle design.

(3) Weath er cond it ions. Plants to be instal ledunder extreme weather conditions will require spe-cial consideration of weather protection, reliability,and redundancy. Heat rejection requires special de-sign consideration in either very hot or very coldweather conditions. For arctic weather conditions,circulating hot water for the heat distribution medi-um has many advantages over steam, and the use ofan ant ifreeze solution in lieu of pure wa ter a s a dis-tribution medium should receive consideration.

3-6. Cycle equipment

a. General r equi r em ents. In addit ion to the primemovers, alternators, and steam generators, a com-plete power plant cycle includes a number of second-

ary elements which affect the economy and perform-ance of the plant.b. M ajor equi pment . Refer to other parts of this

manual for detai led informat ion on steam turbinedriven electric generators and steam generators.c. Second ar y cycle el ement s. Other equipment

items affecting cycle performance, but subordinateto the steam generators and turbine generators, arealso described in other parts of this chapter.

3-7. Steam power plant arrangement

a. General. Small units ut i l ize the t ransverse ar-rangement in the turbine generator bay while the

larger utility units are very long and require end-to-end arrangement of the turbine generators.

b. Typical smal l pl ants. Figures 3-4 and 3-6 showtypical t ransverse smal l plant arra ngements . Sma llunits less than 5000 kW may have the condensers atthe same level as the turbine generator for economya s shown in Figur e 3-4. Figure 3-6 indica tes t hecritical turbine room bay dimensions and the basic

overall dimensions for the small power plants shownin Figure 3-5.


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U. S. Army Corps of Engineers

Figur e 3-4. Typical smal l 2-uni t powerpl ant A.

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a

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Section Il. STEAM GENERATORS AND AUXILIARY SYSTEMS.

tors for a steam power plant can be classi f ied bytype of fuel, by unit size, and by f inal steam condi-tion. Units can a lso be classif ied by t ype of dra ft , bymethod of assembly, by degree of weather protec-tion and by load factor application.

(1) Fu el, general . Type of fuel has a major im-pact on the general plant design in addition to thesteam generator. Fuel selection may be dictated byconsiderations of policy and external circumstances

3-8. Steam generator conventionaltypes and characteristics

a. I ntr oduction. Number, size, and outlet steam-ing conditions of the st eam generators w ill be as de-termined in planning studies and confirmed in the fi-

nal project criteria prior to plant design activities.Note general criteria given in Section I of this chapter under discussion of typical plants and cycles.

b. T ypes and classes. Conventional steam genera-

AND CONDENSER SUPPLIERS SELECTED.

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24990060 electrical engineering electric power plant desing

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