air Pollution Control Systems FOR BOILERS AND INCINERATORS

8/6/2019 air Pollution Control Systems FOR BOILERS AND INCINERATORS

1/121

NAVFAC DM 3.15

ARMY TM 5-815-1

AIR FORCE AFR 19 - 6

AIR POLLUTION CONTROL SYSTEMS

FOR

BOILERS AND INCINERATORS


2/121

REPRODUCTION AUTHORIZATION/RESTRICTIONS

This manual has been prepared by or for the Government and, except to the extentindicated below, is public property and not subject to copyright.

Copyright material included in the manual has been used with the knowledge andpermission of the proprietors and is acknowledged as such at point of use. Anyone

wishing to make further use of any copyrighted materials, by itself an d apartfromthis text, should seek necessary permission directly from the proprietors.

Reprints or republications of this manual should include a credit substantially asfollows: Joint Departments of the Army and Air Force, U.S., Technical ManualTM 5-815-l/AFR 19-6, AIR POLLUTION CONTROL SYSTEMS FORBOILERS AND INCINERATORS.

If the reprint or republication includes copyrighted material, the credit should alsostate: Anyone wishing to make, further use of copyrighted materials, by itself andapart from this text, should seek necessary permission directly from the pro-prietors.


3/121

*TM 5-815-1/ AFR 19-6

Technical ManualNo. 5-815-1AIR FORCE REGULATION

HEADQUARTERSDEPARTMENT OF THE ARMY AND

THE AIR FORCENo. 19-6 WASHINGTON, D.C., 9 May 1988

AIR POLLUTION CONTROL SYSTEMS FORBOILERS AND INCINERATORS

Paragraph

GENERAL

Page

l - l

1 - 2l - 3l - 4

l - ll - ll - l

l - l

2 - l 2 - l2-2 2- l

2-3 2- l2-4 2- l

2-5 2- l2-6 2-32-7 2-3

2-8 2-6

3 - l 3 - l3-2 3-l3-3 3-l3-4 3-23-5 3-2

3-6 3-33-7 3-33-8 3-43-9 3-6

4 - l 4 - l4-2 4-l4-3 4-l

4-4 4-24-5 4-34- 6 4-34-7 4-3

5 - l 5 - l5-2 5- l

5-3 5- l5-4 5-35-5 5-3

6 - l 6 - l

6-2 6-16-3 6- l6-4 6-56-5 6-6

6-6 6-126-7 6-13

6-8 6-156-9 6-16

*This m an ua l sup ersed es TM5- 815-1; AFR 19-6; NAVFAC DM3.15, da ted Nove mb er 1980.

i

Chapter 1.

Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Unique control problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Economic considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 2. INCINERATOR EMISSIONS

Incineration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Types of incinerator waste materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Functions of incinerators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Effect of waste properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Types of incinerators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Particulate emission standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Particulate emission estimating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Sample calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 3. BOILER EMISSIONS

Generation processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Types of fuels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Fuel burning systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Emissionstandards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Formation of emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Fuel selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Emission factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Opacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sample problems of emissions estimating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 4. STACK EMISSION REGULATIONS AND THE PERMITTING PROCESS

Stack emissions ............... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Air quality standards ........... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Permit acquisition process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Mathematical modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Monitoring . . . . . . . .................... . . . . . . . . . . . . . . . . . . . . . . . .Presentation and hearings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Factors affecting stack design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....

MEASURING TECHNIQUES

Criteria.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Stack and source measurement techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Meteorological and ambient air measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Flue gas sampling ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Air pollution project contacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CYCLONES AND MULTICYCLONES

Cyclone.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Cyclone types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Cyclone collection efficiency . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Chapter 5.

Chapter 6.

Cyclone pressure drop and energy requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . .Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Cyclone performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Cyclone operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Selection of materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Advantages and disadvantages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


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*TM 5- 815-1/ AFR 19-6

Chapter 7.

Chapter 8.

Chapter 9.

Chapter 10.

Chapter 11.

Chapter 12.

Chapter 13.

Appendix A:

Bibliography

Glossary

ii

HIGH AND LOW ENERGY SCRUBBER SYSTEMS

Scrubbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Types of scrubbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Treatment and disposal of waste materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Selection of materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Auxiliary equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Advantages and disadvantages.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ELECTROSTATIC PRECIPITATORSElectrostatic precipitator (ESP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Types of electrostatic precipitators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Modes of operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Description of Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Control systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Advantages and disadvantages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FABRIC FILTERS

Fabric filtration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Types of filtering systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Fabric characteristics and selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Materials and construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Auxiliary equipment and control systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Energy requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


SULFUR OXIDES (SOx) CONTROL SYSTEMS

Formation of sulphur oxides (SOx) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Available methods for reducing SOxemission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Procedure to minimize SOxemission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Sample problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

NITROGEN OXIDES (NOx) CONTROL AND REDUCTION TECHNIQUES

Formation of nitrogen oxides . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Factors affecting NOxemissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

NOxreduction techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Post combustion systems for NOxreduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Step-by-step NOxmethod . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

EMISSION CONTROL EQUIPMENT SELECTION FOR INCINERATORS ANDBOILERS

Principles of selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Flue gas properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Particulate properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Application of emission control systems for boilers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Municipal solid waste boilers and boilers using refuse derived fuels . . . . . . . . . . . . . . . . . . . . .

Applications of emission control systems for incinerators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Technical evaluation of control equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Tradeoffs and special considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

FLUIDIZED BED BOILERS

Fluidized bed boilers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Types of fluidized bed boilers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Applications.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Fluidized bed performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Materials and construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Auxiliary equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .


REFERENCES

Paragraph Page

7 - l 7 - l

7-2 7 - l

7-3 7-6

7-4 7-6

7-5 7-6

7-6 7-7

7-7 7-9

8 - l 8-1

8-2 8-1

8-3 8 - l

a- 4 8 - l

8-5 8-3

8-6 8-3

8-7 8-5

8-8 8-7

9 - l 9 - l

9-2 9 - l

9-3 9-4

9-4 9-8

9-5 9-10

9-6 9-109-7 9-10

9-8 9-11

9-9 9-11

10- l10-2

10-310-4

11-l11-211-3

11-4

11-5

10-l

10-l10-7

10-9

11- l11-l11-2

11-4

11-5

12-1 12-1

12-2 12-1

12-3 12-2

12-4 12-2

12-5 12-4

12-6 12-5

12-7 12-6

12-8 12-6

13-113-2

13-313-4

13-513-6

13-7

13-113-1

13-613-813-813-9

13-10

A - l

Biblio-1

Gloss-l


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*TM 5- 815-1/ AFR 19-6

LIST O F FIG URES

Figure No.

l - l .

6-1.6-2.6-3.

6-4.6-5.

6-6.6-7.6-8.

Title

Emissions control procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Cycloneconfiguration.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Types of cyclones in common use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Relative effect of cyclone dimensions on efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Efficiency curve and dimensions for a high efficiency single cyclone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Parallel and series arrangement for cyclones.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Efficiency curve and illustration of a multicyclone unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Size-efficiency curve for high-efficiency (long cone) irrigated cyclone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Particle size distributions curve (by weight) of particulate emitted from uncontrolled power plants(pulverized coal fired boiler) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Fractional efficiency curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Effect of smaller cyclones in parallel on theoretical cyclone collection efficiency . . . . . . . . . . . . . . . . . . . . . . . . .

Effect of altering individual cyclone dimensions on theoretical collection efficiency for an 8 inch diameter

Page

1-2

6-26-36-5

6-66-7

6-86-9

6-106-11

6-126-9.6-10.6-11.

6-136-14

6-15

7-2

7-37-47-5

7-5

7-67-7

8-28-4

8-58-6

9-29-39-49-69-79-8

10-510-6

10-710-810-810-9

11-2

13-113-213-313-413-513-6

13-713-813-9

cyclone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Effects of cyclone inlet velocity and grain loading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Effects of gas viscosity, dust specific gravity, and dust particle size distribution . . . . . . . .

6-12.6-13.

7 - l .7-2.7-3.7-4.7-5.

7-6.7-7.

8-1.8-2.8-3.8-4.

9 - l .9-2.9-3.9-4.9-5.9-6.

10-l.10-2.

10-3.10-4.10-5.

10-6.

11-l.

13-l.13-2.

13-3.13-4.13-5.13-6.13-7.13-8.13-9.

Plate type scrubber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Types of spray and centrifugal scrubbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Types of entrainment and moving bed scrubbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Gas atomized spray (venturi) scrubber . . . . . . . . . . . . . . . . . . . . . . . . . . . .Throat sections of variable venturi scrubbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Spray dryer system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Schematic diagram of scrubber flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Schematic views of flat and tubular surface type electrostatic precipitators . . . . . . . . . . . . . . . . . . .Operating ranges for hot/cold electrostatic precipitators . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Factors affecting particle resistivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bus sections vs. efficiency for different sulfur percentages in coal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Typical baghouse (shake clean) ............... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Fabric filter housing design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Filter shape and arrangement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Reverse flow baghouse (without bag collapse) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Reverse flow cleaning (with bag collapse) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Pulse-jet baghouse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Lime (limestone) injection system schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Magnesia slurry SO2 recovery process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Wellman-Lord SO2 reduction system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Catalytic oxidation system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Single alkali sodium carbonate scrubber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Dual alkali system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Possible NO, reductions vs. load reductions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Types of fluid bed combustors size comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Pressure drop vs. gas velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Velocity vs. bed expansion.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Bubbling bed boiler I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Bubbling bed boiler II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Circulating fluid bed boiler system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Dual bed fluidized bed boiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

SO2 reduction vs. combustion temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NO, emissions vs. combustion temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

iii


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*TM 5-815-1/ AFR 19-6

LIST OF TABLES

Table No.

2-l.2-2.2-3.2-4.

3-l.3-2.

3-3.3-4.3-5.3-6.3-7.

5-l.5-2.5-3.

6-l.6-2.

8-1.

9-l.9-2.9-3.

10-l.10-2.10-3.10-4.

11-l.11-2.

11-3.11-4.

12-1.12-2.12-3.

Waste Classifications.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Ultimate analysis of a typical general solid waste . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Emission factors for refuse incinerators without controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Emission factors for sewage sludge incinerators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Allowable federal emission rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Factors relating to particulate emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Emission factors for bituminous coal combustion without control equipmentEmission factors for fuel oil combustion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Emission factors for natural gas combustion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Emission factors for bark and wood waste combustion in boilers . . . . . . . . . . . . . . . . . . . . . . . .Factors affecting NO, emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

EPA emission sampling techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Air quality sampling method survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ringelmannstandards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Cyclone classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Removal of uncontrolled particulate emissions from combustion processes . . . . . . . . . . . . . . . .

Operating characteristics of precipitators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Performance comparison of fabric filter cleaning methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Properties of fibers for high temperature filtration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Operating characteristics of fabric filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Convertibility of steam boilers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Performance characteristics of flue-gas desulfurization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Typical analysis of fuel oil types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Typical analysis of coal types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General NO, emission and excess air requirements for fuel types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Possible NO, emission reductions attainable with a 50 percent reduction in excess air from normal levels(greater than 10% excess air) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Possible NO, reductions, percent of normal emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Comparison of NO, reduction techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Range of collection efficiencies for common types of particulate control equipment . . . . . . . . . . . . . . . . . . . . . . . . .

Comparison of some dust collector characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

General guidelines in the selection of emission control equipment for boiler flue gases . . . . . . . . . . . . . . . . . . . . . .

Page

2-22-l2-42-5

3-23-4

3-53-63-73-83-9

5-l5-l5-3

6-46-12

8-3

9-59-99-12

10-l10-310-1110-12

11-2

11-311-411-7

12-712-812-10

iv


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TM 5-815-1/ AFR 19-6

CHAPTER 1

GENERAL

1-1. Purposea. This manual is designed to facilitate the identifica-

tion of air pollutant emission rates, and the selection ofcontrol equipment required to meet local, state, andfederal compliance levels. Presented herein are fuelclassifications, burning equipment types, emission ratefactors, emission measuring techniques, control equip-ment types, and control methods. Also included arediscussions of stack dispersion techniques, and controlequipment selection.

b. Each control equipment chapter provides per-formance data and equipment limitations which aid inthe comparative selection of control equipment types.Each chapter includes a discussion of the basic control

theory, various equipment types, collection efficiency,pressure drop, operating requirements and limitations,application, materials of construction, and advantagesand disadvantages in relation to other type controlequipment.

1-2. Scopea. This manual has been limited to the application of

control equipment to fuel burning boilers and incin-erators for the purpose of reducing point-source emis-sion rates. A procedural schematic for its use isillustrated in figure 1-l. Although the selection of asite, a fuel, and burning equipment are outside the

scope of this manual, there are alternatives available tothe engineer in arriving at the least-cost solution to airpollutant problems. Once these factors have beendecided, boiler or incineration emission rates andreduction requirements can be estimated using chap-ters 2 and 3.

b. If emission rates are in compliance with local,state, and federal regulations for point-sources, theireffect on local air quality must yet be ascertained. Suchfactors as stack height and prevailing meteorologicalconditions, while affecting ambient pollution levels, donot have an effect on point-source emission rates. Theyare considered in this manual only to make the reader

aware of their importance. These factors are unique foreach particular site, and usually warrant expert con-sultation. If emission rates for a boiler or incineratorare above local, state or federal requirements, or if air-quality regulations might be violated, selection of apollution control device will be required. The technicaland cost selection of control equipment are embodied inthis manual.

c. Appendix A contains a list of references used inthis manual. A bibliography listing publications of sub-

ject material relating to the topic of this manual can befound at the end of this manual. Also included is a

glossary listing abbreviations and a brief definition ofterminology used in the text.

1-3. Unique control problemsMilitary facilities have air pollution control problemswhich are unique to their mission. Among the problemsare those associated with classified waste disposal,ammunition, plant wastes, chemical warfare wastes,hazardous toxic waste, and radioactive wastes. Eachwill require a consultant or a specialist to help solve theunique problem. Therefore, each unique problem willrequire special handling on a case-to-case basis. The

manual does not include any information on treatmentof emissions, or the incineration of these unique mate-rials.

1-4. Economic considerationsThe selection of one particular type of design for amechanical system for a given application when two ormore types of design are known to be feasible must bebased on the results of a life cycle cost analyses, pre-pared in accordance with the requirements of theDepartment of Defense Construction Criteria Manual(DOD 4270.1-M). Standards for the conduct of all eco-

nomic studies by and for the Department of the Armyand the Department of the Air Force are contained inAR 11-28 and AFR 178-1, respectively. Subject toguidance resulting from implementation of ExecutiveOrder 12003 and related guidance from DOD, the citedeconomic analysis techniques are to remain valid. Thebasic underlying principles and the most commonlyused techniques of economic analysis are described insome detail in a variety of publications and standardtextbooks on engineering economy such as Principlesof Engineering Economy by Grant, Ireson, and Leavenworth; guides published by professional organiza-tions such as the American Institute of Architects LifeCycle Cost Analysis-a Guide for Architects; andhandbooks prepared by government agencies such asthe Naval Facilities Engineering Commands EC Onomic Analysis Handbook, NAVFAC P-442. Clarification of the basic standards and guidelines for aparticular application and/or supplementary standardsfor guidelines which may be required for special casemay be obtained by request through normal channels toHeadquarters of the particular service branchinvolved.

1-


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TM 5-815-1/ AFR 19-6

U.S. Army Corps of EngineersFigure 1-1. Emission control procedure.

1-2


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TM 5-815-1/ AFR 19-6

CHAPTER 2

INCINERATOR EMISSIONS

2-1. IncinerationThis chapter describes and quantifies whenever possi-ble the air pollution particulate emissions which are thedirect result of the incineration process.

a. Incineration process. The incineration processconsists of burning solid, semisolid, liquid, or gaseouswaste to produce carbon dioxide, water, and ash. It isan efficient means of reducing waste volume. The solid,incombustible residue of incineration is inert, sanitary,and sensibly odorless.

b. Emissions. Incineration contributes to air pollu-tion. The polluting emissions are ash, hydrocarbons,sulfur oxides (SO,), nitrous oxides (NO,), chlorides,

and carbon monoxide. Estimating absolute quantitiesof these pollutants is not an exact science, but historicaltesting data from typical incinerators allow estimates ofemissions to be made. Also, measurement methods forincinerator emissions are sufficiently advanced to per-mit actual data to be obtained for any existing incin-erator. These measurements are preferred in all casesover analytical estimates.

c. Pollution codes. Air pollution particulate emis-sions must be considered in regard to federal, state andlocal pollution codes. In general, incinerators cannotmeet current pollution code requirements without par-ticulate control devices.

2-2. Types of incinerator waste materials

Waste materials are classified as shown in table 2-l. Anultimate analysis of a typical general solid waste isshown in table 2-2. Because of the wide variation incomposition of waste materials, an analysis of the actualmaterial to be incinerated should be made before sizingincineration equipment.

Table 2-2

Ultimate analysis of a typical general solid waste

Moisture 35.00%

Carbon 20.00%

Oxygen 18.00%

Hydrogen 2.50%Nitrogen 0.60%

sulfur 0.06%Noncombustibles 23.84%

100.00%

From: Environmental Protection Agency, Control Techniques forParticulate Emissions for Stationary Sources

2-3. Function of incineratorsIncinerators are engineered apparatus capable of with-standing heat and are designed to effectively reduce

solid, semi-solid, liquid, or gaseous waste at specifiedrates, so that the residues contain little or no combusti-ble material. In order for an incinerator to meet thesespecifications, the following principles of solid fuel com-bustion generally apply:

-Air and fuel must be in the proper proportion,-Air and fuel, especially combustible gases, must

be properly mixed,-Temperatures must be high enough to ignite both

the solid fuel and the gaseous components,-Furnace volumes must permit proper retention

time needed for complete combustion,-Furnace configurations must maintain ignition

temperatures and minimize fly-ash entrainment.

2-4. Effect of waste propertiesThe variability of chemical and physical properties ofwaste materials, such as ash content, moisture content,volatility, burning rate, density, and heating value,makes control of incineration difficult. All of these fac-tors affect to some degree the operating variables offlame-propagation rate, flame travel, combustion tem-perature, combustion air requirements, and the needfor auxiliary heat. Maximum combustion efficiency ismaintained primarily through optimum incinerator

design.

2-5. Types of incineratorsa. Mu nicipal incinerators. Incinerators are classi-

fied either as large or small units, with the dividingpoint at a processing rate of 50 tons of waste per day.The trend is toward the use of the smaller units becauseof their lower cost, their simplicity, and lower air emis-sion control requirements. There are three major typesof municipal incinerators.

(1) Rectangular incinerators. The most commonmunicipal incinerator is the rectangular type.The multiple chamber units are either refrac-

tory lined or water cooled and consist of acombustion chamber followed by a mixingchamber. The multicell units consist of two ormore side-by-side furnace cells connected to acommon mixing chamber. Primary air is fedunder the grate. Secondary air is added in themixing chamber to complete combustion. Asettling chamber often follows the mixingchamber. Ash is removed from pits in the bot-tom of all of the chambers.

2-1


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TM 5-815-1/ AFR 19-6

TABLE 2-1

WASTE CLASSIFICATIONS

TYPE

0

1

2

3

4

5

6

APPROXI-MATECOMPOSI-

DESCRIP- PRINCIPAL TION %TION COMPONEN TS BY WEIGHT

Trash Highly combustible waste; Trash 100paper, wood, ca rdboa rd ca r -tons, including up to 10%t r e a t e d p a p e r s , p l a s t i c o rrubber scraps ; commercia la n d i n d u s t r i a l s o u r c e s .

R u b b i s h C o m b u s t i b l e waste , p a p e r , Rubbishcartons , rags , wood scraps , 80combustible floor sweepings, Garbagedomestic, commercial, and 20i n d u s t r i a l s o u r c e s .

Refuse Rubbish and garbage; Rubbishr e s i d e n t i a l s o u r c e s . 50

Garbage50

Garbage Animal and vegetable wastes; Garbager e s t a u r a n t s , h o t e l s , 65m a r k e t s ; i n s t i t u t i o n a l c o m - R u b b i s hmercia l , and c lub sources 35

Animal C a r c a s s e s , o r g a n s , s o l i d Animal

sol ids organ i c was te s f rom andand h o s p i t a l , l a b o r a t o r y , Humanorgan ic aba t to i r s , an im a l pounds T i s s u ewaste and simila r sources . 100

Gaseous , Indus tr ia l process was tes Variablel iqu id o u c h a s , t a r , p a i n t ,o r semi- solvent , s ludge and fumes .l iqu idwastes

Semi- Indus t r i a l p roces s was te s , Var iab le

solid s u c h a s , r u b b e r , p l a s t i cand and wood.sol idwastes

MOISTURECONTENT

10

25

50

70

85

Dependenton pre-dominantcomponents

Dependenton pre-dominantcomponents

INCOM-

BUSTIBLESOLIDS %

5

10

7

5

5

Varies Variesaccording to according towastes wastes

Varies Varies

according to according towastes wastes

BTUVALUE/LB OFREFUSE

AS FIRED

8500

6500

4300

2500

1000

U. S. Army Corps of Engineers.

(2) Vertical circular incinerators. Waste is usu-ally fed into the top of the refractory linedchamber. The grate consists of a rotating cone

in the center surrounded by a stationary sec-tion with a dumping section around it. Armsattached to the rotating cone agitate the wasteand move the ash to the outside. Primary air isfed underneath the grate. Overtire air is fedinto the upper section of the chamber.

(3) Rotary kiln incinerators. Rotary kiln incin-erators are used to further the combustion ofwaste that has been dried and partially burnedin a rectangular chamber. The waste is mixed

2-2

with combustion air by the tumbling action ofthe kiln. Combustion is completed in the mix-ing chamber following the kiln where secon-

dary air is added. The ash is discharged at theend of the kiln.

b. Industrial and commercial incinerators. Indus-trial and commercial incinerators generally fall into sixcategories. The capacities of these incinerators gener-ally range from a half to less than 50 tons per day. They

are usually operated intermittently.(1) Single chamber incinerators. Single chamber

incinerators consist of a refractory lined com-bustion chamber and an ash pit separated by a


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TM 5-815-1/ AFR 19-6

grate. There is no separate mixing chamber.An auxiliary fuel burner is normally providedunderneath the grate. The units are normallynatural draft (no fans). Emissions from singlechamber units are high because of incompletecombustion.

(2) Multiple chamber incinerators. Multiplechamber refractory lined incinerators nor-mally consist of a primary chamber, a mixing

chamber and a secondary combustion cham-ber. The primary chamber is similar to a singlechamber unit. Air is fed under the grate andthrough overfire air ports. Secondary air isadded in the mixing chamber. Combustion iscompleted in the secondary combustion cham-ber where some settling occurs. These unitsare also normally natural draft.

(3) Conical incinerators. Conical incineratorsknown commonly as tee-pee burners havebeen used primarily in the wood productsindustry to dispose of wood waste. Since theycannot meet most local particulate emissionrequirements, and since wood waste is becom-ing more valuable as a fuel, conical incineratorsare being phased out.

(4) T rench in cinerators. Trench incinerators areused for disposal of waste with a high heatcontent and a low ash content. The incineratorconsists of a U-shaped chamber with airnozzles along the rim. The nozzles are directedto provide a curtain of air over the pit and toprovide air in the pit.

(5) Controlled-air incinerators. Controlled-airincinerators consist of a refractory lined pri-mary chamber where a reducing atmosphere ismaintained and a refractory lined secondarychamber where an oxidizing atmosphere ismaintained. The carbon in the waste burns andsupplies the heat to release the volatiles in the

waste in the form of a dense combustiblesmoke. Overtire air is added between cham-bers. The smoke is ignited in the secondarychamber with the addition of air. Auxiliary fuelburners are sometimes provided in the secon-dary chamber if the mixture does not supportcombustion. Air for this type of incinerator isprovided by a forced draft fan and is controlled

by dampers in order to provide the properdistribution. Controlled-air incinerators areefficient units with low particulate emissionrates.

(6) Fluidized bed incinerators. Fluidized bedincinerators consist of a refractory lined ver-tical cylinder with a grid in the lower part thatsupports a bed of granular material, such assand or fine gravel. Air is blown into the cham-ber below the grid causing the bed to fluidize.

Waste is fed above the bed and then mixes withthe media where it burns. Fluidized bed incin-erators are normally self sustaining andrequire an auxiliary fuel burner only for start-up. Fluidizing air is supplied by a centrifugalblower. Ash leaves the fluidized bed incin-erator when it becomes fine enough to be car-ried out by the flue gas. Fluidized bed incin-erators are capable of burning most types ofliquid or solid waste.

c. Sludge incinerators. Sludge incinerators handlematerials high in water content and low in heat content.Two types of incinerators are normally used for sludgeincineration.

(1)Multiple hearth incinerators. Multiple hearthincinerators consist of vertically stackedgrates. The sludge enters the top where theexiting flue gas is used to drive off themoisture. The burning sludge moves throughthe furnace to the lower hearths. Ash isremoved from under the last hearth.

(2) Fluidized bed incinerator. Fluidized bed incin-erators are particularly well suited for sludgedisposal because of the high heat content of thebed media. Heat from the combustion of thesludge is transferred to the bed media. Thisheat is then transferred back to the incomingsludge, driving off the moisture.

2-6. Particulate emission standardsThe Clean Air Act requires all states to issue regula-tions regarding the amount of particulate emissionfrom incinerators. Each state must meet or exceed theprimary standards set forth by the federal act, limiting

particulate emissions for incinerators with a chargingrate of more than 50 tons per day of solid to .08 grainsper standard cubic foot (gr/std ft

3) of dry gas at 12

percent carbon dioxide (CO2). Federal guidelines forsewage sludge incinerators limit emissions to 1.3pounds (lbs) per ton of dry sludge input and opacity to20 percent maximum. No federal guidelines currentlyexist for gaseous emissions. State and local regulationsmay meet or exceed the federal guidelines. These reg-ulations are subject to change and must be reviewedprior to selecting any air pollution control device.

2-7. Particulate emission estimating

In order to select a proper pollution control device, thequantities of particulate emissions from an incineratomust be measured or estimated. Measurement is thepreferred method. For new incinerator installationswhere particulate emissions must be estimated, tables2-3 and 2-4 should be used unless concurrent dataguaranteed by a qualified Vendor is provided.

a. Factors affecting emission variability. The quan

tity and size of particulate emissions leaving the fur-nace of an incinerator vary widely, depending upon

2- 3


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2-4


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TM 5-815-1/ AFR 19-6

TABLE 2-4

EMISSION FACTORS FOR SEWAGE SLUDGE INCINERATORS

Emissions*Uncon t ro l led

P o l l u t a n t l b / t o n

P a r t i c u l a t e 100

S u l f u r d i o x i d e 1

Carbon monoxide Neg

Ni t ro g en o x i d es ( a s NO2) 6

Hydrocarbons 1 . 5

Hydrogen chloride gas 1 . 5

* U n i t w e i g h t s i n t e r m s o f d r i e d s l u d g e .

From: Envi ronmenta l Pro tec t ionEmission Factors.

such factors as incinerator design, refuse type, incin-erator capacity, method of feeding, and method of oper-ation. Improved incinerator performance reduces bothdust loading and mean particle size.

(1)

(2)

(3)

Incinerator capacity. Large incinerators burnrefuse at higher rates creating more turbulentgas flow conditions at the grate surface. Rapid,turbulent, combustion aided by the use of moreunderfire air causes particle suspension andcarry over from the incinerator grate surfaceresulting in higher emission rates for largeincinerators.Underfire air flow. The effect of increasingunderfire grate air flow is to increase particu-late emission rate.

Excess air. Excess air is used to control com-bustion efficiency and furnace temperatures.Incinerators are operated at levels of excess airfrom 50 percent to 400 percent. However, par-ticulate emission levels increase with theamount of excess air employed. Increases inexcess air create high combustion gasvelocities and particle carry over. Excess air isimportant as a furnace temperature controlbecause incomplete combustion will occur atfurnace temperatures below 1400 degreesFahrenheit, and ash slagging at the grate sur-face and increased NO, emissions will occurabove furnace temperatures of 1900 degreesFahrenheit.

Agency, Compilat ion of Air

(4) Opacity. For information on the use of visibleopacity measurement as an aid to achievingefficient combustion, see paragraph 3-8.

b. Data reduction. The state regulations for particu-late emissions are expressed in a variety of units. Thefollowing techniques permit the user to reduce particu-late test data to grains per dry standard cubic foot at 12percent CO2, as well as to convert other particulateconcentration units, as used by some states, to thisbasis.

(1) Test data conversion to grains per dry stand-ard cubic foot at 12 percent CO2. Equation 2-lapplies.

0.68C s at 12 percent CO2 = CO 2

x (tm + 460) x C(eq. 2-l)

p

where: Cs at 12 percent CO2 = particulateconcentration in grains per dry standard cubicfoot at gas conditions corrected to 12 percentCO 2 and standard temperature of 68 degreesFahrenheit.

C = particulate concentration attest conditions in grains perdry cubic foot of gas

t m = gas temperature at the testequipment conditions

C O2 = percent by volume of theCO, in the dry gas

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TM 5-815-1/ AFR 19-6

P = barometric pressure ininches of mercury at thetest equipment conditions.

(2) To convert particulate loadings given aspounds per 1000 pounds of dry gas at 50 per-cent excess air, equation 2-2 applies.

C s at 12 C at 50 percent EApercent CO

2=

CO2 (eq. 2-2)x .325 x A

Tx M

AA

where: C at 50 percent EA = pounds ofparticulate per 1000 pounds of gas at 50 per-

cent excess air

AT=theoretical air required per

A A actual air used

M = Molecular weight of the gassample

=A T N 2 - 3.788 (02- .5 CO)

A A N 2(eq. 2-3)

M = .16 CO2 + .04 02 + 28 (eq. 2-4)

where: N2 = percent N2 from Orsat anal-

ysis

O2 = percent 02 from Orsat anal-ysis

CO = percent CO from Orsatanalysis

C O2 = percent CO, from Orsatanalysis

(3) To convert grains per dry standard cubic foot

at 50 percent excess air to grains per drystandard cubic foot at 12 percent CO2, equa-tion 2-5 applies.

Csat 12

percent CO2 =18 x Cs at 50 percent EA

CO2A T

(eq. 2-5)

xA A

(4) To convert pounds of particulate per ton ofrefuse charged to grains per dry standardcubic foot at 12 percent CO2, equation 2-6applies.

Cs at 12 lbs of particulatepercent CO2 = tons-of refuse

x . 4 2 x 1 06x 1

(eq. 2-6)

GCV Fc

where: GCV = gross calorific value ofwaste, British thermalunits (Btu)/lb

F c = carbon F factor, std ft3/mil-

lion (MM)Btu

F = 0.321 x 106x percent carbon

cGCV

(eq. 2-7)

Percent carbon is by weight from the ultimate analy-sis of the refuse. The GCV and tons of refuse must beconsistent with the ultimate analysis. If the ultimateanalysis is on a dry basis, the GCV and tons of refusemust be on a dry basis.

(5)

(6)

To convert grains per dry standard cubic foot

at 7 percent 02 to grains per dry standardcubic foot at 12 percent CO2, equation 2-8applies.

Cs at 12percent CO2 = 1.714

O2x Cs at 7 Percent 02x

CO2

(eq. 2-8)

To convert pounds of particulate per millionBritish thermal units fired to grains per drystandard cubic foot at 12 percent CO2, equa-tion 2-9 applies.

Cs at 12 lbs of particulatepercent CO

2= MMBtu

x 840

(eq. 2-9)

Fc

2-8 Sam ple c alc ulations

a. An industrial multichamber incinerator burns atype I waste at 10 percent moisture of the analysisshown below. What is the estimated particulate emis-sion rate in grains per dry standard cubic foot at 12percent CO2?

Waste Analysis (Percent by Weight on Wet Basis)

(1)

(2)

(3)

Carbon 50 percentHeating value 8500 Btu/lb

Table 2-3 lists industrial multichamber incin-erators as having a particulate emission factorof 7 lb/ton of refuse.

Using equation 2-7,

Fc

= 0.321 x 106x 50 = 1888

8500

Using equation 2-6,

C s a t 12 .42 x 106 1

percent CO2

=

7 x x8500 1888

= 0.183 gr/std ft3

b. Test data from an incinerator indicates a particu-late concentration of 0.5 gr/ft

3at 9 percent CO2. Cor-

rect the particulate concentration to grains per drystandard cubic foot at 12 percent CO2. Test conditionswere at 72 degrees Fahrenheit and a barometric pres-sure of 24 inches of mercury.

2- 6


15/121

(1) Using equation 2-1,

C s at 12 0.5 x0.68 (72 + 460)

xp e r c e n t C O2 9 24

= 0.84 gr/std ft3

c. The emission rate of an incinerator is 10 lb/1000 lb

of dry flue gas at 50 percent excess air. The Orsatanalysis is 8.0 percent O2, 82.5 percent N2, 9.5 percent

CO 2 and 0 percent CO. Convert the emission rate tograins per dry standard cubic foot at 12 percent CO 2.


AT = 82.5 - 3.788(8.0-.5(0)) = 0.633

A A 82.5


M = .16(9.5) + .04(8.0) + 28 = 29.84


C s at 12= 10 x .325 x .633 x 29.84

percent CO2 9.5

TM 5-815-1/ AFR 19-6

d. An incinerator burning waste of the analysisshown below has a measured emission rate of 5 pounds/MMBtu. What is the expected particulate emission ratein grains per dry standard cubic foot at 12 percent CO2?

Waste Analysis

Carbon 35 percent by weight on dry basis

Heating Value 6500 Btu/pound as firedMoisture 21 percent

(1)

(2)

(3)

In order to use equation 2-7, the percent car-bon and the heating value must be on the samebasis.

Percent C on wet basis =35 x (100-21) = 28

100

Using equation 2-7,

F =0.321 x 10

6x 28

=c 6500

1382

Using equation 2-9,

Cs at 12

percent CO2= 5 x 8 4 0

1383= 6.46 gr/std ft

3 = 3.04 gr/std ft3

2- 7


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TM 5-815-1/ AFR 19-6

CHAPTER 3

BOILER EMISSIONS

3-1. Generation processesThe combustion of a fuel for the generation of steam orhot water results in the emission of various gases andparticulate matter. The respective amounts and chem-ical composition of these emissions formed are depen-dent upon variables occurring within the combustionprocess. The interrelationships of these variables donot permit direct interpretation by current analyticalmethods. Therefore, most emission estimates arebased upon factors compiled through extensive fieldtesting and are related to the fuel type, the boiler type

and size, and the method of tiring. Although the use of

emission factors based on the above parameters canyield an accurate first approximation of on-site boileremissions, these factors do not reflect individual boiler

operating practices or equipment conditions, both ofwhich have a major influence on emission rates. Aproperly operated and maintained boiler requires less

fuel to generate steam efficiently thereby reducing theamount of ash, nitrogen and sulfur entering the boilerand the amount of ash, hydrocarbons, nitrogen oxides(NO,) and sulfur oxides (SO

x) exiting in the flue gas

stream. Emissions from conventional boilers are dis-cussed in this chapter. Chapter 13 deals with emissionsfrom fluidized bed boilers.

3-2. Types of fuelsa. Coal. Coal is potentially a high emission produc-

ing fuel because it is a solid and can contain largepercentages of sulfur, nitrogen, and noncombustibles.

Coal is generally classified, or ranked, according toheating value, carbon content, and volatile matter. Coalranking is important to the boiler operator because itdescribes the burning characteristics of a particularcoal type and its equipment requirements. The maincoal fuel types are bituminous, subbituminous,anthracite, and lignite. Bituminous is most common.Classifications and analyses of coal may be found in

Perrys Chemical Engineering Handbook,b. Fuel oil. Analyses of fuel oil may be found inPerrys Chemical Engineering Handbook.

(1)Distillates. The lighter grades of fuel oil (No.1,No.2) are called distillates. Distillates are cleanburning relative to the heavier grades becausethey contain smaller amounts of sediment, sul-fur, ash, and nitrogen and can be fired in avariety of burner types without a need for pre-heating.

(2) Residuals. Residual fuel oils (No.4, No.5,No.6) contain a greater amount of ash, sedi-ment, sulfur, and nitrogen than is contained indistillates. They are not as clean burning as thedistillate grades.

c. Gaseous fuel. Natural gas, and to a limited extentliquid petroleum (butane and propane) are ideallysuited for steam generation because they lend them-selves to easy load control and require low amounts ofexcess air for complete combustion. (Excess air isdefined as that quantity of air present in a combustionchamber in excess of the air required for stoichiometric

combustion). Emission levels for gas firing are lowbecause gas contains little or no solid residues, noncom-

bustibles, and sulfur. Analyses of gaseous fuels may befound in Perrys Chemical Engineering Handbook.

d. Bark and wood waste. Wood bark and woodwaste, such as sawdust, chips and shavings, have longbeen used as a boiler fuel in the pulp and paper andwood products industries. Because of the fuels rela-tively low cost and low sulfur content, their use outsidethese industries is becoming commonplace. Analyses ofbark and wood waste may be found in EnvironmentalProtection Agency, Control Techniques for ParticulateEmissions from Stationary Sources. The fuels low

heating value, 4000-4500 British thermal units perpound (Btu/lb), results from its high moisture content(50-55 percent).

e. Municipal solid waste (MSW) and refuse derived fuel (RDF). Municipal solid waste has historically beenincinerated. Only recently has it been used as a boilerfuel to recover its heat content. Refuse derived fuel is

basically municipal solid waste that has been preparedto burn more effectively in a boiler. Cans and othernoncombustibles are removed and the waste is reducedto a more uniform size. Environmental ProtectionAgency, Control Techniques for Particulate Emissionsfrom Stationary Sources gives characteristics of refuse

derived fuels.

3-3. Fuel burning systemsa. Primary func t ion . A fuel burning system

provides controlled and efficient combustion with aminimum emission of air pollutants. In order to achievethis goal, a fuel burning system must prepare, dis-tribute, and mix the air and fuel reactants at theoptimum concentration and temperature.

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TM 5-815-1/ AFR 19-6

b. Types of equipment.(1) Traveling grate stokers. Traveling grate

(2)

(3)

(4)

stokers are used to burn all solid fuels exceptheavily caking coal types. Ash carryout fromthe furnace is held to a minimum through useof overfire air or use of the rear arch furnacedesign. At high firing rates, however, as muchas 30 percent of the fuel ash content may be

entrained in the exhaust gases from grate typestokers. Even with efficient operation of agrate stoker, 10 to 30 percent of the particulateemission weight generally consists ofunburned combustibles.

Spreader stokers. Spreader stokers operate onthe combined principles of suspension burningand nonagitated type of grate burning. Par-ticulate emissions from spreader stoker firedboilers are much higher than those from fuelbed burning stokers such as the traveling gratedesign, because much of the burning is done insuspension. The fly ash emission measured at

the furnace outlet will depend upon the firingrate, fuel sizing, percent of ash contained in thefuel, and whether or not a fly ash reinjectionsystem is employed.

Pulverized coal burners. A pulverized coalfired installation represents one of the mostmodern and efficient methods for burningmost coal types. Combustion is more completebecause the fuel is pulverized into smaller par-ticles which require less time to burn and thefuel is burned in suspension where a bettermixing of the fuel and air can be obtained.Consequently, a very small percentage of

unburned carbon remains in the boiler fly ash.Although combustion efficiency is high, sus-pension burning increases ash carry over fromthe furnace in the stack gases, creating highparticulate emissions. Fly ash carry over canbe minimized by the use of tangentially firedfurnaces and furnaces designed to operate attemperatures high enough to melt and fuse theash into slag which is drained from the furnacebottom. Tangentially fired furnaces and slag-tap furnaces decrease the amount of fuel ashemitted as particulates with an increase inNO

x

emissions.Fuel oil burners. Fuel oil may be prepared forcombustion by use of mechanical atomizingburners or twin oil burners. In order for fuel oilto be properly atomized for combustion, itmust meet the burner manufacturers require-ments for viscosity. A fuel oil not heated to theproper viscosity cannot be finely atomized andwill not burn completely. Therefore, unburnedcarbon or oil droplets will exit in the furnaceflue gases. A fuel oil heated above the proper

viscosity may ignite too rapidly forming pulsa-tions and zones of incomplete combustion atthe burner tip. Most burners require an atom-izing viscosity between 100 and 200 SayboltUniversal Seconds (SUS); 150 SUS is gener-ally specified.

(5) Municipal solid waste and refuse derived fuelburning equipment. Large quantities of MSW

are fired in water tube boilers with overfeedstokers on traveling or vibrating grates.Smaller quantities are fired in shop assembledhopper or ram fed boilers. These units consistof primary and secondary combustion cham-bers followed by a waste heat boiler. The com-bustion system is essentially the same as thecontrolled-air incinerator described in para-graph 2-5(b)(5). The type of boiler used forRDF depends on the characteristics of thefuel. Fine RDF is fired in suspension. Pel-letized or shredded RDF is fired on a spreaderstoker. RDF is commonly fired in combination

with coal, with RDF constituting 10 to 50 per-cent of the heat input.

3-4. Emission standardsThe Clean Air Act requires all states to issue regula-tions regarding the limits of particulate, SOx and NOxemissions from fuel burning sources. State and localregulations are subject to change and must be reviewedprior to selecting any air pollution control device. Table3-l shows current applicable Federal Regulations forcoal, fuel oil, and natural gas. The above allowableemission rates shown are for boilers with a heat input of250 million British thermal units (MMBtu) and above.

Table 3-1

Allow able federal emission rates

Fuel Particulate SO2 NO x Opacity

Coal 0.1 lb/MMBtu 1.2 lb/MMBtu .7 lb/MMBtu 20 Percent

Fuel Oil 0.1 lb/MMBtu 0.8 lb/MMBtu .3 lb/MMBtu 20 PercentNaturalGas 0.1 lb/MMBtu - .2 lb/MMBtu 20 Percent

From: 40CFR86-National Primary and Secondary Ambient AirQuality Standards.

3-5. Formation of emissionsa. Combustion parameters. In all fossil fuel burning

boilers, it is desirable to achieve a high degree of com-

bustion efficiency, thereby reducing fuel consumptionand the formation of air pollutants. For each particulartype fuel there must be sufficient time, proper tem-perature, and adequate fuel/air mixing to insure com-plete combustion of the fuel. A deficiency in any of thesethree requirements will lead to incomplete combustionand higher levels of particulate emission in the form ofunburned hydrocarbon. An excess in time, tem-perature, and fuel/air mixing will increase the boilerformation of gaseous emissions (NOx). Therefore, thereis some optimum value for these three requirements

3- 2


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TM 5-815-1/ AFR 19-6

regarding fuel selection, such as AR 420-49 for theArmys use.

3-7. Emission factors

Emission factors for particulates, SOx, and NO

x, are

presented in the following paragraphs. Emission fac-tors were selected as the most representative valuesfrom a large sampling of boiler emission data and havebeen related to boiler unit size and type, method offiring and fuel type. The accuracy of these emissionfactors will depend primarily on boiler equipment age,condition, and operation. New units operating at lowerlevels of excess air will have lower emissions than esti-mated. Older units may have appreciably more. There-fore, good judgement should accompany the use ofthese factors. These factors are from, EnvironmentalProtection Agency, Compilation of Air PollutantEmission Factors. It should be noted that currentlyMSW and RDF emission factors have not been estab-lished.

a. Particulate emissions. The particulate loadingsin stack gases depend primarily on combustion effi-ciency and on the amount of ash contained in the fuelwhich is not normally collected or deposited within theboiler. A boiler firing coal with a high percentage of ashwill have particulate emissions dependent more on thefuel ash content and the furnace ash collection or reten-tion time than on combustion efficiency. In contrast, aboiler burning a low ash content fuel will have particu-late emissions dependent more on the combustion effi-ciency the unit can maintain. Therefore, particulateemission estimates for boilers burning low ash contentfuels will depend more on unit condition and operation.Boiler operating conditions which affect particulateemissions are shown in table 3-2. Particulate emission

factors are presented in tables 3-3, 3-4, 3-5 and 3-6.

b. Gaseous emissions.

(1) S ulfur oxide emissions. During combustion,sulfur is oxidized in much the same way carbonis oxidized to carbon dioxide (CO

2). Therefore,

almost all of the sulfur contained in the fuel willbe oxidized to sulfur dioxide (SO

2) or sulfur

trioxide (SO2) in efficiently operated boilers.

Field test data show that in efficiently operatedboilers, approximately 98 percent of the fuel-bound sulfur will be oxidized to SO

2, one per-

cent to SO3, and the remaining one percent

sulfur will be contained in the fuel ash. Boilers

with low flue gas stack temperatures may pro-duce lower levels of SO, emissions due to theformation of sulfuric acid. Emission factors forSO

xare contained in tables 3-3, 3-4, 3-5, and

3-6.(2) Nitrogen oxide emissions. The level of nitro-

gen oxides (NOx) present in stack gases

depends upon many variables. Furnace heatrelease rate, temperature, and excess air are

3-3

within the boilers operating range which must be metand maintained in order to minimize emission rates.The optimum values for time, temperature, and fuel-airmixing are dependent upon the nature of the fuel (gas-eous, liquid or solid) and the design of the fuel burningequipment and boiler.

b. Fuel type.

(1) Gaseous fuels. Gaseous fuels burn more read-ily and completely than other fuels. Becausethey are in molecular form, they are easilymixed with the air required for combustion,and are oxidized in less time than is required toburn other fuel types. Consequently, the

amount of fuel/air mixing and the level ofexcess air needed to burn other fuels are mini-mized in gas combustion, resulting in reducedlevels of emissions.

(2) Solid and liquid fuels. Solid and liquid fuelsrequire more time for complete burningbecause they are tired in droplet or particleform. The solid particles or fuel droplets mustbe burned off in stages while constantly beingmixed or swept by the combustion air. The sizeof the droplet or fired particle determines howmuch time is required for complete combus-tion, and whether the fuel must be burned on agrate or can be burned in suspension. Systemsdesigned to fire solid or liquid fuels employ ahigh degree of turbulence (mixing of fuel andair) to complete combustion in the requiredtime, without a need for high levels of excess

air or extremely long combustion gas paths. Asa result of the limits imposed by practicalboiler design and necessity of high tem-perature and turbulence to complete particle

burnout, solid and liquid fuels develop higheremission levels than those produced in gas fir-ing.

3-6. Fuel selectionSeveral factors must be considered when selecting afuel to be used in a boiler facility. All fuels are notavailable in some areas. The cost of the fuel must befactored into any economic study. Since fuel costs varygeographically, actual delivered costs for the particulararea should be used. The capital and operating costs ofboiler and emission control equipment vary greatlydepending on the type of fuel to be used. The method

and cost of ash disposal depend upon the fuel and thesite to be used. Federal, state and local regulations mayalso have a bearing on fuel selection. The Power Plantand Fuel Use Act of 1978 requires that a new boilerinstallation with heat input greater than 100 MMBtuhave the capability to use a fuel other than oil or naturalgas. The Act also limits the amount of oil and naturalgas firing in existing facilities. There are also regula-tions within various branches of the military service


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TM 5-815-1/ AFR 19-6

Table 3 -2

FACTORS RELATING TO PARTICULATE EMISSIONS

F u e l c h a r a c t e r i s t i c s :High ash content

High mois ture contentS i z i n gHi g h d eg ree o f a t o m i za t i o n

o r p u l v e r i z a t i o n

B o i l e r c h a r a c t e r i s t i c s :High combust ion rate

Dry b o t t o m as h co l l ec t i o n

W et b o t t o m as h co l l ec t i o nF l u e - g a s r e c i r c u l a t i o nM et h o d o f f i r i n g

T an g en t i a lHo r i zo n t a l

Sp read e r s t o k e r

B o i l e r o p e r a t i o n :

Im p ro p e r o i l p re s s u reI m p r o p e r o i l v i s c o s i t y

High combust ion air

t em p era t u reNonuniform air f low

( b e t w e e n r e g i s t e r o rair compartments)

Hi g h ex ces s a i r

Low furnace temperature

Equipment condi t ion:Worn burner (nozzles ,

s p r a y e r , p l a t e s , e t c . )

Un c l ean o r s l ag g i n g b o i l e r

t u b e s u r faces

U. S. Army Corps of Engineers

major variables affecting NOxemission levels,but they are not the only ones. Therefore,while the emission factors presented in tables3-3, 3-4, 3-5, and 3-6 may not totally reflecton site conditions, they are useful in determingif a NOx emission problem may be present.Factors which influence NOx formation areshown in table 3-7.

3-8. OpacityVisual measurements of plume opacity (para 5-3j) canaid in the optimization of combustion conditions. Par-ticulate matter (smoke), the primary cause of plume

opacity, is dependent on composition of fuel and effi-

3-4

L ev e l o f Pa r t i cu l a t e E m i s s i o n s

Hi g h Low

X -

X -

- X

X -X -- XX -

- XX -

X -

X -X -

X -X -X -

X -

X -

- X

ciency of the combustion process. Smoke varies in colorbut is generally observed as gray, black, white, brown,blue, and sometimes yellow, depending on the condi-tions under which certain types of fuels or materials areburned. The color and density of smoke is often anindication of the type or combustion problems whichexist in a process.

a. Gray or black smoke is often due to the presenceof unburned combustibles. It can be an indicator thatfuel is being burned without sufficient air or that there

is inadequate mixing of fuel and air.b. White smoke may appear when a furnace is oper-

ating under conditions of too much excess air. It mayalso be generated when the fuel being burned contains


20/121

3-5


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TM 5-815-1/ AFR 19-6

TABLE 3-4

EMISSION FACTORS FOR FUEL OIL COMBUSTION

Pollutant

Particulateb

Sulfur dioxided

Sulfur triorided

Carbon monoxidee

Hydrocarbons(total, as CH4)

f

(Nitrogen oxides(total, as NO2)

Type of Boilera

Power Plant Industrial and Commercial DomesticResidual Residual Oil Distillate Oil Distillate Oil

lb/103

gal

c

157S2S

lb/103

gal lb/103

gal lb/103

gal

c

157S

2 2.5

142S 142S2S 2S 2S

5 5 5

1 1 1 1

105(50)8gh

60fi

22 18

a.

b.

c.

d.e.

f.

g.

h.

i.

Boilers can be classified, roughly, according to their gross (higher) heat input rate asshown below.Power plant (utility) boilers: greater than 250 x 10

6

Btu/hrIndustrial boilers: greater than 15 x 10

6

Commercial boilers: greater than 0.5 x 106

,but less than 250 x 10

6

Btu/hrbut legs than 15 x 10

6

Btu/hrDomestic (residential) boilers: less than 0.5 x 10

6

Btu/hrParticulate is defined in this table as that material collected by EPA Method 5 (fronthalf catch).

Particulate emission factors for residual oil combustion are best described, on theaverage, as a function of fuel oil grade and sulfur content, as shown below.

Grade 6 oil: lb/10

3

gal = 10 (S) + 3Where: S is the percentage. by weight, of sulfur in the oilGrade 5 oil: 10 lb/10

3

galGrade 4 oil: 7 lb/10

3

galS is the percentage, by weight, of sulfur in the oil.Carbon monoxide emissions may increase by a factor of 10 to 100 if a unit is improperlyoperated or not well maintained.Hydrocarbon emissions are generally negligible unless unit is improperly or not wellmaintained. In which case emissions may increase by several orUse 50 lb/10

3

gal for tangentially fired boilers and 105 lb/10 3ders of magnitude.

gal for all others,at full load, and normal (greater than 15 percent) excess air. At reduced loads, NOxemissions are reduced by 0.5 to 1 percent , on the average. for every percentagereduction in boiler load.Several combustion modifications can be employed for NOx reductions: (1) limitedexcess air firing can reduce NOx emissions by 5 to 30 percent. (2) staged combustioncan reduce NOx emissions by 20 to 45 percent, and (3) flue gas recirculation canreduce NOx emissions by 10 to 45 percent. Combinations of the modifications have beenemployed to reduce NOx emissions by as much as 60 percent in certain boilers.

Nitrogen oxides emissions from residual oil combustion in industrial and commercialboilers are strongly dependent on the fuel nitrogen content and can be estimated more

accurate1lb N02/103 by the following empirical relationship:gal = 22 + 400 (N)

2

Where: N is the percentage, by weight, of nitrogen in the oil.Note: For residual oils having high (greater than 0.5 percent by Weight) nitrogencontents, one should use 120 lb N0 2/10

3

gal as an emission factor.From: Environmental Protection Agency, "Compilation of Air Emission Factors".

U.S. Corps of Engineers

excessive amounts of moisture or when steam atomiza- MMBtu) to grains per standard cubic foot (gr/std ft3)

tion or a water quenching system is employed. dry basis is accomplished by equation 3-l.c. A blue or light blue plume may be produced by the

burning of high sulfur fuels. However, the color is onlyobserved when little or no other visible emission ispresent. A blue plume may also be associated with the

burning of domestic trash consisting of mostly paper orwood products.

E = C x Fd x20.9

x 700020.9 - %02

(eq. 3-l)

d. Brown to yellow smoke may be produced by pro-cesses generating excessive amounts of nitrogen diox-ide. It may also result from the burning of semi-solidtarry substances such as asphalt or tar paper encoun-tered in the incineration of building material waste.

3-9. Sample problems of emission estima-ting

a. Data Conversion. Pounds per million Btu (lb/

3-6

where: E = pound/MMBtu

C = concentration, gr/std ft3dry

%O 2 = percent by volume of oxygen in theflue gas

Fd

= dry F factor, std ft3/MMBtu

Fuel Type Fd

Anthracite coal lO100

Bituminous coal 9780

Fuel oil 9190

Gaseous fuels 8710

Wood 9240

Wood bark 9600


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TM 5-815-1/ AFR 19-6

TABLE 3-5

EMISSION FACTORS FOR NATURAL GAS COMBUSTION

P o l l u t a n t

P a r t i c u l a t e s 5-15 5-15 5-15

S u l f u r o x i d e s ( S O2 )a

0.6 0.6 0.6

Carbon monoxide 17 17 20

Hydrocarbons (as CH4)

Nitrogen oxides (NO2)

Power Plant

lb/MCF gas

1

700b

Type of Unit

I n d u s t r i a l D o m e s t i c a n dProcess Commercial

B o i l e r Heat ing

lb/MCF gas lb/MCF gas

3 8

(120-230)c

(80-120)d

a . B as ed o n an av e rag e s u l fu r co n t en t o f n a t u ra l g a s o f 2 0 0 0gr/mil l ion cubic feet (MMCF).

b . Us e 3 0 0 l b / M C F fo r t an g en t i a l l y f i r ed u n i t s .c . T h i s r e p r e s e n t s a t y p i c a l r a n g e f o r m a n y i n d u s t r i a l

b o i l er s . F o r l a r ge i n du s tr i a l u n i t s ( g r e a t e r t h a n 10 0M M B t u / h r ) u s e t h e NOx factors presented for power

p l a n t s .d . Use 80 for domest ic heat ing uni ts and 120 for commercial

u n i t s .

From: Environmental Protect ion Agency, Compilat ion of Air

Emission Factors.

b. S am ple Problem Number1. An underfed stokerfired boiler burns bituminous coal of the analysis shownbelow. If this unit is rated at 10 MMBtu per hour (hr) offuel input, what are the estimated emission rates?

Bituminous Coal Analysis (percent by weight)

Ash 13.0Sulfur 0.7

Heating value 12,360 Btu/pound

(1) Using table 3-3 (footnote e), particulate emis-sions are given as 5A pound/ton of coal where Ais the percent ash in the coal.

(a) 5 x 13% ash = 65 pounds of particulate/tonof coal.

(b) 65 pounds/ton x ton/2000 pounds = .0325pound of particulate/pound of coal

(c) (.0325 lb/lb) x lb of coal x l06Btu

12,360 Btu MMBtu= 2.63 lbs/MMBtu

(2) Using table 3-3, SO, emissions are given as38S pound/ton of coal, where S is the percentsulfur in the coal.

(a) 38 x .7% sulfur = 26.6 pounds of SO2/ton ofcoal

(b) 26.6 pounds/ton = ton/2000 pounds =.0133 pound of SO2/pound of coal

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TABLE 3-6

EMISSION FACTORS FOR BARR ANDWOOD WASTE COMBUSTION IN BOILERS

Pol lutant

P a r t i c u l a t e sa

Barkb

With f ly-ash re inject ionc

Without fly-ash reinjectionWood/bark mixture

b

With f ly-ash re inject ionc

Without fly-ash reinjectionWood d

Sulfur oxides (SO2)

e

Carbon monoxidef

Hydrocarbonsf

Nitrogen oxides (NO2)

Emissionsl b / t o n

7550

4530

5-151 .52-602-70

10

a. These emission factors were determined for boilersburning gas or oil as an auxiliary fuel, and it wasassumed all particulates resulted from the waste fuelalone. When coal is burned as an auxiliary fuel , theappropriate emission factor from Table 3-3 should be usedin addition to the above factor.

b. These factors based on an as-fired moisture content of50 percent.

c. This factor represents a typical dust loading reaching

the control equipment for boilers employing fly-ashre in jec t ion .

d. This waste includes clean, dry (5 to 50 percent moisture)sawdust, shavings, ends, etc. and no bark. For welldesigned and operated boilers, use lower value and highervalues for others. This factor is expressed on anas-fired moisture content basis assuming no fly-ashre in jec t ion .

e. This factor is calculated by material balance assuming amaximum sulfur content of 0.1 percent in the waste. Whenauxil iary fuels are burned, the appropriate factors fromTables 3-3, 3-4, and 3-5 should be used in addition todetermine sulfur oxide emissions.

f. Use lower values for well designed and operated boilers.

From: Environmental Protection Agency, "Compilation of AirEmission Factors"

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TABLE 3-7

FACTORS AFFECTING NOxEMISSIONS

Variable Effect on NOX Emission

Increasing

Heat release rate

Heat quenching rate

(wa t e r co o l ed fu rn aces )

Boiler capacity

Boiler load

Excess air

Furnace temperature

Combustion air temperature

Fuel nitrogen content

Fuel oxygen content

Fuel moisture content

Distance between burners

Number of burners per unit

Fu e l / a i r m i x i n g ( t u rb u l en ce )

Time available for particle burnout

(tangentially fired boilers)

U. S. Army Corps of Engineers.

lb of coal(c) (.0133 lb/lb) x

12,360 Btu

106

BtuxMMBtu

= 1.08 lbs/MMBtu(3) Using table 3-3, NOx emissions are given as 15

pounds/ton of coal.(a) 15 pounds/ton x ton/2000 pounds = .0075

pound of NOx/pound of coal

lb of coal(b) (0075 lb/lb) x x

106

Btu

12,360 Btu MMBtu

= .61 lbs/MMBtu

(4) If particulate emission must be reduced to .2

Increase Decrease

pounds/MMBtu, the required removal effi-ciency is determined as,

.2

l - =2.63 .924 (92.4%)

(5) If the oxygen in the flue gas is estimated at 5percent by volume, what is the dust con-centration leaving the boiler in grains/stand-ard cubic foot (dry)?Using equation 3-1,

7000 x 2.63 20.9 - 5C =

9780 20.9

= 1.43 gr/std ft3dry

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c. Sample Problem Number 2. A boiler rated at 50

MMBtu/hr burns fuel oil of the analysis shown below.What are the estimated emission rates?

#6 Fuel Oil Analysis (percent by weight)

Sulfur 2Nitrogen .2Heating Value 150,000 Btu per gallon (gal)

(1) Using table 3-4, particulate emissions aregiven as [10(S) + 3] pound/1000 gal, where S isthe percent sulfur in the fuel oil.

(a) (10 x 2% sulfur) + 3 = 23 pounds of par-ticulate/1000 gal

gal of oil(b) 23 lbs/l000 gal x x

106Btu

150,000 Btu MMBtu

= .15 lb/MMBtu(2) Using table 3-4, SO, emissions are given as

157S pound/1000 gal, where S is the percentsulfur in the fuel oil.

(a) 157 x 2% sulfur = 314 pounds/1000 gal

gal of oil(b) 314 lbs/l000 gal x x

106Btu

150,000 Btu MMBtu= 2.09 lb/MMBtu

(3) Using table 3-4, NOx emissions are given as

[22 + 400 (N)2

] pound/1000 gal, where N is thepercent nitrogen in the fuel oil.

(a) 22 + 400 x (.2)2

= 38 pounds of NOx/1000

galgal of oil

(b) 38 lbs/l000 gal x x10

6

Btu

150,000 Btu MMBtu

= .25 lb/MMBtu

d. Sample Problem Number 3. A commercial boilerrated at 10 MMBtu/hr tires natural gas with a heating

value of 1000 Btu/ft3. What are the estimated particu-late and NO

xemission rates?

(1) Using table 3-5, particulate emissions are

given as a maximum of 15 pound per millioncubic feet (MCF) of natural gas.

(a) 15 lb/MCF xMCF

x10 x 10

6Btu

106

ft3

h r

f t3

x = .15lb/hr1000 Btu

(b) .15 lb/hr x =h r

.015 lb/MMBtu10MMBtu

(2) Using table 3-5 (footnote d), NOx emissions

are given as 120 pound/MCF of natural gas.

(a) 120 lb/MCF x x10 x 10

6BtuMCF

1 06

f t3

f t3

X = 1.2 lb/hr1000 Btu

(b) 1.2 lb/hr x =h r .12 lb/MMBtu10 MMBtu

e. Sample Problem Number 4. A spreader stokerfired boiler without reinjection burns bark and coal incombination. The bark firing rate is 2000 pound/hr. Thecoal firing rate is 1000 pound/hr of bituminous coal with

an ash content of 10 percent and a heating value of12,500 Btu/pound. What is the estimated particulate

emission rate from this boiler?

(1)

(2)

Using table 3-6, the bark firing particulateemission rate is given as 50 pounds/ton of fuel.

50 pounds/ton x ton/2000 pounds x 2000pound/hr = 50 pounds/hr of particulate frombark.Using table 3-3, the coal firing particulateemission rate for a heat input of 12.5 MMBtu/hr is 13A pounds/ton of fuel.

(13 x 10) pound/ton x 1000 pound/hr xton/2000 pound = 65 pounds/hr of particulate

from coal.(3) The total particulate emission rate from the

boiler is,50 pounds/hr from bark + 65 pounds/hr

from coal = 115 pounds/hr

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CHAPTER 4

STACK EMISSION REGULATIONS AND THE PERMITTING PROCESS

4-1. Stack emissions

The discharge of pollutants from the smokestacks ofstationary boilers and incinerators is regulated by bothFederal and State Agencies. A permit to construct ormodify an emission source will almost certainly berequired.

a. The emissions must comply with point source reg-ulations, dependent upon characteristics of the pointsource, and also with ambient air quality limitationswhich are affected by physical characteristics of the

location and the meteorology of the area of the newsource.

b. The permitting procedure requires that estimates

be made of the effect of the stack emissions on theambient air quality. Predictive mathematical modelsare used for arriving at these estimates.

c. Due to the time requirements and the complexityof the process and the highly specialized nature of manyof the tasks involved, it is advisable to engage consul-tants who are practiced in the permitting proceduresand requirements. This should be done at a very earlystage of planning for the project.

4-2. Air quality standardsa. Federal standards-Environmental Protection

Agency Regulations on National Primary and Secon-

dary Ambient Air Quality Standards (40 CFR 50).b. State standards. Federal installations are also

subject to State standards.

4-3. Permit acquisition processa. New SourceReview. The state agency with juris-

diction over pollution source construction permits

should be contacted at the very beginning of the projectplanning process because a New Source Review (NSR)application will probably have to be filed in addition toany other State requirements. A New Source Review isthe process of evaluating an application for a Permit toConstruct from the Air Quality Regulatory Agency

having jurisdiction.b. Planning. Consideration of air quality issues very

early in the planning process is important because engi-neering, siting, and financial decisions will be affectedby New Source Review. Engineering and constructionschedules should include the New Source Review pro-

cess which can take from 6 to 42 months to completeand which may require the equivalent of one year ofmonitoring ambient air quality before the review pro-cess can proceed.

c. Emission levels. One must file for a New SourceReview application if, after use of air pollution controlequipment, the new boiler or incinerator will result inincreased emissions of any pollutant greater than aspecified limit. Proposed modifications of existingboilers and incinerators that will cause increases inpollutant emissions greater than certain threshold lev-els (de minimis emission rate) require New SourceReview.

d . General determinants for steps required for per-

mit t ing . Steps required for a New Source Reviewdepend upon the location of the new source, charac-teristics of the other sources in the area, and on discus-

sions with the State Air Pollution Control Agencies,possibly the EPA, and how well one is current with thechanges in regulations and administrative practices.Because of the constantly changing pi

Documents

air Pollution Control Systems FOR BOILERS AND INCINERATORS