EPA/450/2-81/017e
        U.S. Environmental Protection Agency




           Air Pollution Training Institute
              COURSE  81:422
                 3rd Edition
     AIR POLLUTION CONTROL
       ORIENTATION  COURSE
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Unit 5
Control Techniques for Gaseous and Particulate Pollutants

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United States           Air Pollution Training Institute       EPA 450/2-81-017e
Environmental Protection     MD 20                  June 1981
Agency              Environmental Research Center
	Research Triangle Park NC 27711	
Air	


APTI

Course S 1:422    3rd Edition

Air Pollution Control

Orientation Course


Units

Control Techniques for Gaseous

and Paniculate Pollutants


Prepared By:                  Under Contract No.
Northrop Services, Inc.            68-02-2374
P. 0. Box 12313                EPA Project Officer
Research Triangle Park, NC 27709       R. E. Townsend

               United States Environmental Protection Agency
               Office of Air, Noise, and Radiation
               Office of Air Quality Planning and Standards
               Research Triangle Park, NC 27711
                    ******
This is one  of nine self-instructional units in  the

Air  Pollution Control Orientation Course SI:422.


This unit consists of a cassette tape and this  flip-

book, which you will use simultaneously.



Turn the page and read the tips on effective use

of this material.

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                 Tips for Effective Use *>f This Material
    1. Listen to the recorded script while you go through this flipbook. The recorded
      portion is coordinated with the flipbook. Wait for the tape to finish the details
      of one point before studying the next point on the page.
    2. When you hear a "beep" on the tape, direct your attention to the next page in
      the flipbook.
    3. Pay attention to both words and pictures — they both convey important informa-
      tion. The flipbook will usually summarize main points or give examples.
    4. Stop the tape at any point if you wish to spend more time reading a page in the
      flipbook. Rewind the tape if you wish to review a portion of the script.
    5. Review the lesson objectives before answering the questions at the end of each
      lesson. Ask yourself whether you have mastered the information indicated in the
      objectives.
    6. Answer the questions. They will help you assess your progress in mastering the
      course materials.
    7. Check your answers. The correct responses can be found on the page(s) fol-
      lowing the questions.
    8. If you answer a question incorrectly, review the flipbook material covering the
      subject matter. Now Turn On the Tape Recorder and Begin Lesson I.
                               • •
                               11



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     Lesson I:  Control Techniques Not Requiring
                      Control Devices


                           Objectives

      1. Name the two physical forms of air pollutants.
      2. Identify four techniques for reducing pollutant emissions that do not require
        the use of emission control devices.

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   Two Forms of Air Pollutants
   Gaseous
Particulate
Primary Gaseous Pollutants
  • sulfur oxides     • odors
  • acid gases        • carbon monoxide
  • nitrogen oxides   • hydrocarbons

Common Particulate Pollutants
  • cement dust      • metal fumes
  • smoke           • fly ash
  • acid mists

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    Emission Reduction Techniques
  Not Using Emission Control Devices
  •  Process change
  •  Change in fuel
  •  Good Operating practices
    • good housekeeping
    • maintenance
  •  Plant shutdown
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         Process Change
     Fossil-fuel fired,

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         Change in Fuel
  ••&•&&. '• '*&'$"%$*"..' '• :'&?:'j
. &&^&^&*fr

yp&~g W-vJ^!*;?-
     Good Operating Practices
   Bad
Good
 ri^?,v%
      •&
Bad
Good
Good Housekeeping     Maintenance

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            Plant Shutdown
                          8
           National Emission Estimates
                     1970-1977
              (Millions of metric tons/year)
Year
1970
1971
1972
1973
1974
1975
1976
1977
TSP(a)
22.2
20.9
19.6
19.2
17.0
13.7
13.2
12.4
S0x(a)
29.8
28.3
29.6
30.2
28.4
26.1
27.2
27.4
N0x(a)
19.6
20.2
21.6
22.3
21.7
21.0
22.8
23.1
VOC(b)
29.5
29.1
29.6
29.7
28.6
26.9
28.7
28.3
CO
102.2
102.5
103.8
103.5
99.7
96.9
102.9
102.7
(a) FSF  Total Suspended Paniculate matter in the case ot emissions, just paniculate
      mailer
  SO\  Sulfur Oxides
  NOx - Oxides of Nitrogen
(b) V'OC - Volatile Organic Compounds hydrocarbons etc.
                          9

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    .-.j'f" 'r'"'- ••••£>.*t?.'•„£>-• •'••'
      ':
Gray or black emissions
from smoke stacks are
easily seen by everyone
— but no one sees the
gaseous emissions.
                                 10
                               Lesson I
                               Questions

  1. Name the two forms of air pollutants.
  2. Four of the following are methods of pollutant reduction that do not require
    the use of emission control devices. Which one is not?
       a. tall chimneys                        d. change in fuel
       b. plant shutdown                     e. process change
       c. good operating practices
 Answers on next page.
                                   11

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                              Lesson I
                              Answers
 1.  gaseous, paniculate
 2.  a. tall chimneys
After checking your responses, please turn on the tape recorder.


                                   12
    Lesson  II:  Control Techniques for  Gaseous
                            Emissions
                              Objectives
  1. Name the four main techniques used in devices that control gaseous emissions.
  2. Identify the definition of each of the following terms: absorption, adsorption,
     condensation, and combustion.
  3. Given a diagram of a control device (as it appears in this flipbook), name the
     control device and tell whether it is of the adsorption, absorption, condensa-
     tion,  or combustion type.
  4. Identify the factors that must be considered when choosing a device for the
     control of gaseous emissions.
                                  13

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   Control Techniques for
     Gaseous Emissions

    • Adsorption
    • Absorption
    • Condensation
    • Combustion
            14
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         Adsorption

 The removal of a gaseous pollu-
 tant from a gas stream by allow
 ing the pollutant molecules in
 the gas stream to become
 attached to a solid surface.
             15

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  Adsorption Design Factors

   Nature of the contaminant
   Surface area  of adsorbent
   Temperature and pressure
   Nature of adsorbent
               16
  How do we dispose of adsorbents?
Dispose of both the
pollutant and the
adsorbent together
                 17
Remove the
pollutant from the
solid surface and
re-use adsorbent bed
(regeneration)

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Adsorption Systems

Nonregenerative
   • Have thin beds
   • Commonly used where
     there are low concen-
     trations of pollutants
     in a gas stream
Regenerative
   • Have thick beds
   • Used for solvent or
     hydrocarbon recovery
                     Regenerative System
                        Clean gas out
                            A
            Dirty
            gas in
       Steam for
      regeneration
                                  18
                                         Pollutant and steam out
    Dirty gas in
                  Water out

                 r< Water in

                  Particulate
                    filter
                                                              Clean gases
                X
             Cooling coil
             (if required)
Blower
   Unit #1-
   Removing
   pollutants
   Activated
    carbon
      Regenerative
          System
Unit #2-
Being
regenerated

Activated
  carbon
Collected
pollutant
                                 Clean air out
                               Low pressure steam
                                 for regeneration
                                   1 Q

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        Absorption
The dissolving of a gaseous
pollutant in a liquid solvent
             20
Factors Affecting Absorption

 Type of pollutant
 Type of solvent
 Temperature of system
 Pressure on system
             21

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With absorption equipment we
try to get as much gas-liquid
mixing as possible.
              22
     Absorption Equipment

   Spray tower
   Spray-chamber
   Venturi scrubber
   Packed column
              23

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                nr Clean gas out
   Packed
  Column
Liquid in
                     Packing material
                     Dirty gas in
                 Liquid and pollutant out
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      Condensation occurs when:
    Pressure increased
    Heat extracted from a system
    (the most economical method
    is temperature reduction)
               25

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   Condensers are usually used
   in conjunction with:

     • afterburners
     • absorbers
     • adsorption units
               26
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       Surface Condenser
      (Temperature Reduction)
Cooling
medium
Clean gas out
 in
Cooling
medium V
Condensate out
 out
                27
                      NJ
         Cooling medium: water or air

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                   Clean gas out
   Contact
  Condenser
  (Temperature
   Reduction)
Dirty
gas in
Water
 in
              28
                Water and condensate out
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               Combustion
  The result of the combination of
  oxygen with a combustible
  material, usually accompanied
  by heat and light
              29

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Combustion is commonly used
as a control technique for
hydrocarbon emissions.
             30
     Combustion Equipment

   Flare
   Thermal incinerator
   Catalytic incinerator
              31

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    Flare
            32
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      Thermal Incinerator
         (Afterburner)
 Dirty
 gas


 Fuel
 and
 air


 Dirty
 gas
Ave. temp:
1400-1500 °F
       I
          Clean
out
             33

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            Catalytic  Incinerator
Fuel

 Air

Dirty
 gas
              Preheat
              burner
                                        Catalyst
600-900DF
800-1100°F
                               Clean
                                out
                                34
                      Choice of Control Technique
     Some questions to consider:
        1. Will the pollutant burn?
        2. Is the product of combustion a pollutant?
        3. Is the pollutant soluble in water or another solvent?
        4. Can the pollutant be easily condensed?
        5. Is carbon adsorption applicable?
        6. What is the age  of the plant?
        7. Is re-use of pollutant desirable?
        8. What is the impact of control cost on selling price of the product?
        9. What are equipment costs?
       10. What are utility requirements?
                                 35

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                      Lesson II
                      Questions
     1. Name the four main techniques used in devices that control gaseous emissions.
     2. The phrase, "the removal of a gaseous pollutant from a gas stream by allowing
      the pollutant molecules to become attached to a solid surface" defines which of
      the following terms?
       a. condensation               d. adsorption
       b. absorption                e. evaporation
       c. combustion               f. none of the above
                        36
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                                Clean gas out
3. The diagram at the right
  depicts which of the following  "
  type of control device?

  a. adsorption
  b. absorption
  c. combustion
                                      Liquid in
                                      Packing material
                                       Dirty gas in
                                 Liquid and condensate out

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   4. The device depicted in question No. 3 is a:
      a. flare.                    d. regeneration adsorber.
      b. surface condenser.            e. contact condenser.
      c. catalytic incinerator.           f. packed column.
                        38
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 5. Which of the following is not a factor to consider when choosing a device for
   the control of gaseous emissions?
    a. color of the pollutant            d. age of the plant
    b. equipment costs               e. whether or not the pollutant
    c. whether or not the pollutant         can be reused
      will burn                   f. solubility of the pollutant
 Answers on next page.


                       39

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                               Lesson II
                                Answers

  1. adsorption, absorption, condensation, and combustion
  2. d. adsorption
  3. b. absorption
  4. f. packed column
  5. a. color of the pollutant
 After checking your responses, please turn on the tape recorder.
                                    40
          Lesson III: Control Techniques for
                    Particulate  Emissions
                              Objectives
1.  Name the 4 types of paniculate matter.
2.  Categorize each of the 4 types of paniculate matter as either solid or liquid.
3.  Identify the factors that must be considered before choosing a paniculate con-
   trol device.
4.  Name the 5 main types of paniculate control devices.
5.  Given a diagram or picture of a control device (as it appears in this flipbook),
   name the control device.
6.  Describe, briefly, the ideal solution to the problem of collected paniculate
   matter disposal.

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                42
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   Common Terms Used to Describe
         Particulate Matter
     Solid
       Dust
       Smoke
       Fumes
Liquid

• Mist

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   Information Needed About Gases and Particles

   Particle size
   Gas flow rate
   Temperature
   Moisture content
   Type and concentration of particles in gas stream
   Significant characteristics of particles — abrasive,
   explosive, flammable, acidic, etc.


   Degree of Control Desired (i.e. efficiency)

           weight of particles entering—weight of particles leaving
     Efficiency —
              total weight entering control equipment
                      44
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           Particulate Control Devices

        Settling chamber
        Cyclone
        Wet collector (scrubber)
        Electrostatic precipitator
        Fabric filter (baghouse)

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 Settling Chamber
Dirty gas in
                              Clean gas out
Collection force: gravity
Collection efficiency: low
Initial cost: inexpensive
Operating cost: low
                             Dust hoppers
                   46
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  Outlet
  tube

  Dirty
  gas in
  Cone
  Dust
  hopper
            Clean
           gas out
Cyclone
              Cylinder
               Collection efficiency: low to medium
               Initial cost: inexpensive
               Operating cost: low
          Collected
          dust out
                  4-7

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                 Several small
                 cyclones are used
                 together to increase
                 collection efficiency.
                 48
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           Clean gas out
  Dirty
  gas in
       gas out
                            Outlet tube
                             Spin vanes
    Multiple Cyclone
   t
Collector Element
Collected
dust out
                 49

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       Wet
   Collector
   (Scrubber)
                         Spray
C
 ollection efficiency: medium to high
Initial cost: moderate
Operating cost: high
                                              Clean gas out
                          Water and condensate out
                             50
   High
  voltage
            Electrostatic  Precipitator
            to plates      (Plate  Type)
            to wires
 Dirty
 gas in
Discharge
electrode (wire)
                             gas ,n ,'^
                                    '••••*
 Collection efficiency: medium to high
 Initial cost: high
 Operating cost: moderate to high
                                                  Weights

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           Electrostatic Precipitator
                (Tube Type)
  Dirty
  gas in
                   Clean
                   gas out
Dirty
gas in
                    52
                                    Clean
                                    gas out;
mf|||F
                                   Spray


                                   Discharge
                                   electrode
                                    (wire)
              Weights
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   Mechanism for shaking,
   rapping, or vibrating bags

           Clean
           air out
           Dirty
           air in
  Fabric Filter
    (Baghouse)
   Collection efficiency: high
   Initial cost: high
   Operating cost: high
                                      Clean
                                       air
                                       out
                                    air in
                     53

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  Particulate control systems often
  require two or more control devices to
  obtain the highest possible efficiency.

For example,
     Cyclone

   to collect large
     particles
     Electrostatic
     Precipitator
      to collect
     remaining
    small particles
                   54
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     Disposal of Collected Material
 Most dry particulate material
 will be disposed of in land-fills
 or dumps.
Water slurries go to basins or
sewers or treatment plants.
         The ideal solution is to recycle the collected material.

                   55

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                        Lesson III
                        Questions
     1.  Name at least four common kinds of paniculate matter.
     2.  Which of the following is (are) liquid particle(s)?
        a. dust                     c. fumes
        b. mist                     d. smoke
     3.  Which of the following should be considered before choosing a particulate
       control device?
        a. moisture content of stack gas       d. type & concentration of
        b. gas flow rate                   particles
        c. characteristics of particles        e. temperature
                                 f. all of the above
                             56
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     4. Name the five main types of particulate control devices.
     5. The control device depicted at the right is a(n)-.
        a. settling chamber.
        b. cyclone.
        c. wet collector.
        d. electrostatic precipitator.
        e. fabric filter.
        f. none of the above.
     6. Describe briefly the ideal solution to the problem of
       collected particulate matter disposal.
Spra
                                        Water and condensate out
     Answers on next page.

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                           Lesson III
                            Answers
   1. dust, smoke, fumes, mist
   2. b. mist
   3. f. all of the above
   4. settling chamber
     cyclone
     wet collector (or scrubber)
     electrostatic precipitator
     fabric filter (or baghouse)
   5. c. wet collector (or scrubber)
   6. The recycling of the collected material
  After checking your responses, review any material that you are not sure of, and
  then take the Unit Test which begins on the next page.
                               58

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                             Unit Test


      The two physical forms of air pollutants are:
        a. liquid and paniculate.              d. gaseous and vaporous.
        b. liquid and gaseous.                 e. none of the above.
        c. gaseous and paniculate.
      Which of the following is not a method for reducing pollutant emissions?
        a. tall chimneys                     d. process change
        b. plant shutdown                   e. good operating practices
        c. change in fuel
                                 -o

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    3. Which of the following is not a technique used in devices that control gaseous
      emissions?
       a. adsorption                   d. combustion
       b. condensation                 e. electrostatic precipitation
       c. absorption
    4. The phrase "the dissolving of a gaseous pollutant in a liquid solvent" defines
      which of the following terms?
       a. adsorption                   d. combustion
       b. absorption                   e. none of the above
       c. condensation
                            60
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    The diagram at the right depicts
    which of the following types of
    control device?
      a. adsorption
        absorption
        combustion
        condensation
        electrostatic precipitation
b.
c.
d.
e.
                               Clean gas out
                                 A
              Regenerative System
                           Dirty
                           gas in
                                  Pollutant and steam
Steam for
regeneration
                           61

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  6. Which of the following must be considered when choosing a device for the
    control of gaseous emissions?
      a. equipment costs                 d. whether or not the pollutant
      b. whether or not the pollutant            can be reused
         will burn                    e. solubility of the pollutant
      c. age of the plant
  7. Which of the following is not a common kind of paniculate matter?
      a. mist                          d. vapor
      b. dust                          e. fumes
      c. smoke
  8. Which of the following should be considered before choosing a device to
    control paniculate pollutants?
      a. moisture content of stack gas         d. type and concentration of
      b. gas flow rate                       particles
      c. characteristics of particles           e. temperature
                                    f. all of the above
                              62
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 9. The control device depicted at the right is a(n):
    a. settling chamber.
    b. cyclone.
    c. wet collector.               Dirty gas in
    d. electrostatic precipitator.          r-..:. A;
    e. fabric filter.
A A Clean gas out


        Outlet tube


        Spin vanes
t                                             Collected
                                             dust out
                                    Collector Element

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       10. Describe briefly the ideal solution to the problem of collected particulate
         matter disposal.
      Answers on next page.
                               64
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                          Answers

     1. c. gaseous and particulate
     2. a. tall chimneys
     3. e. electrostatic precipitation
     4. b. absorption
     5. a. adsorption
     6. a-e. equipment costs, whether or not the pollutant will burn, age of the plant,
         whether or not the pollutant can be reused, and solubility of the
         pollutant.
     7. d. vapor
     8. f. all of the above
     9. b. cyclone
    10. The recycling of the collected material.
                             65

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