Stationary Source Controls
& Source Sampling
Marti Blad
Ph.D., P.E.
What we will learn
 Control of air pollution is possible
 Physical, chemical or biological
 Control of air pollution is not perfect
 “Shell game”
 Control mechanisms for particles are different from
those that control gasses
 Examples of types of controls
 How air pollution control devices work
 Sampling of point sources
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Stationary Source Control
 Philosophy of pollution prevention
 Modify the process: use different raw materials
 Modify the process: increase efficiency
 Recover and reuse: less waste = less pollution
 Philosophy of end-of-pipe treatment
 Collection of waste streams
 Add-on equipment at emission points
 AP control of stationary sources
 Particulates
 Gases
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Particulate Control Technologies
 Remember this order:
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Settling chambers
Cyclones
ESPs (electrostatic precipitators)
Spray towers
Venturi scrubbers
Baghouses (fabric filtration)
 All physical processes
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Settling Chambers
 “Knock-out pots” = initial separators
 Gravity and inertia forces
 Simplest, cheapest, no moving parts
 Least efficient & large particles only
 Creates solid-waste stream
 Can be reused
 Pictures on next slides
 Baffle, Gravity, Centrifugal
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Variety of
styles
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Simple boxes= collection
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Cyclones
 Inexpensive, no moving parts
 More efficient than settling chamber
 still better for larger particles
 Single cyclone or multi-clone design
 In series or in parallel
 Creates solid-waste stream
 Picture next slide
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Notice shapes and fans
Dry collection systems
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Venturi Scrubber
Detail illustrates cloud atomization from highvelocity gas stream shearing liquid at throat
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Venturi Scrubber
 High intensity contact between water and gas
=> high pressure drop
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Venturi action modified spray tower
High removal efficiency for small particles
Creates water pollution stream
Can also absorb some gaseous pollutants
(SO2)
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Venturi and scrubbers
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Spray Towers
 Water or other liquid “washes out” PM
 Less expensive than ESP but more than
cyclone, still low pressure drop
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Variety of configurations
Higher efficiency than cyclones
Creates water pollution stream
Can also absorb some gaseous pollutants
(SO2)
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Spray Tower
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ESPs
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Electrostatic precipitator
More expensive to install,
Electricity is major operating cost
Higher particulate efficiency than cyclones
Can be dry or wet
Plates cleaned by rapping
Creates solid-waste stream
Picture on next slide
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Electrostatic Precipitator Concept
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Same
Size &
Shape
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Electrostatic Precipitator
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Electrostatic Precipitator
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Baghouses
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Fabric filtration – vacuum cleaner
High removal efficiency for small particles
Not good for wet or high temperature streams
Uses fabric bags to filter out PM
Inexpensive to operate
Bags cleaned by periodic shaking or air pulse
Creates solid-waste stream
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Pulse-Air-Jet Type
Baghouse
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Baghouse in a Facility
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Baghouse= fabric filters
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Stationary Source
Controls:
Gaseous Pollutants
and Air Toxics
Source of Gaseous Pollutants
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Controlling Gaseous Pollutants:
SO2 & NOx
 Modify Process
 Switch to low-sulfur coals
 Desulfurize coal
 Washing-bioclean
 Gasification
 Increase efficiency
 Low-NOx burners
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Recover & Reuse Heat
 Staged combustion
 Multi chambers
 Better process control
 Flue-gas recirculation
 Gas is heat sink
 Absorbs heat from high flame area
 Lowers peak flame temperatures
 Picture next slide
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How FGR fits in process
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Controlling Gaseous Pollutants:
CO & VOCs
 Wet/dry scrubbers
 Used for PM but double w wet
 Absorber solutions
 NOx and SOx included
 Combustion Process
 Proper operating conditions
 Low NOx burners
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Scrubbers / Absorbers
 SO2 removal: “FGD” (flue gas desulfurization)
 Lime/soda ash/citrate absorbing solutions
 Can create useable by-product OR solid waste
stream
 NOx removal—catalytic and non-catalytic
 Catalyst = facilitates chemical reaction
 Ammonia-absorbing solutions
 Process controls favored over this technology
 CO & CO2 removal
 Some VOC removal
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VOC / CO Process Control
 Keep combustion HOT
 Reuse & recycle heat
 Control cold start-ups, shut-downs, wet inputs
 wood-fired, chemical incinerators, boilers
 Increase residence time of gas in combustor
 Unfortunately, things that reduce NOx tend to
increase VOC’s
 Atmosphere in air combustion 78% N2
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How it might look together
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Flares
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Thermal Oxidation
 Chemical change = burn
 CO2 and H2O ideal end products of all processes
 Flares (for emergency purposes)
 Incinerators
 Direct
 Catalytic = improve reaction efficiency
 Recuperative: heat transfer between inlet /exit gas
 Regenerative: switching ceramic beds that hold
heat, release in air stream later to re-use heat
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Thermal Oxidation
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Actual Oxidizers
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Regenerative
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Recuperative
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Carbon Adsorption
 Good for organics (VOCs)
 Both VOCs and carbon can be recovered when
carbon is regenerated (steam stripping)
 Physical capture
 Adsorption & Absorption
 Bettermarriageblanket.com
 Under-tec.com (farty pants)
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Adsorb
Absorb
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Stack
Sampling
Are you afraid
of heights?
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Stack sampling site setup
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What is source sampling?
 Sample air pollutants at the source
 Stacks, vents, pt. of compliance, etc.
 Sample specific pollutants
 Standard methods/protocols
 Determine amount of a pollutant emitted
 Pollutant concentration
 Mass pollutant per unit volume exhaust gas
 Pollutant mass rate
 Mass pollutant emitted over a time interval
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Why is source sampling done?
 Evaluate process efficiency
 Evaluate equipment & control performance
 Calculate process material balances
 Evaluate process economics
 Input of models (point source)
 Regulatory compliance verification/permit
review
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Before Sampling Sources
 Plan what will be done
 Describe sampling objective, pollutants & site
 Identify responsible persons
 Sampling locations & access
 Standard methods
 CFR, ASTM, AAC
 Sample type (grab, integrated or instrument)
 Methods – field sampling & lab analyses
 QA/QC requirements (field and lab)
 Health & safety considerations (plan)
 Each test is done 3 times
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Standard Methods – Basic
 Method 1
 Sample port location & number of ports, determine
absence of cyclonic flow
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Method 2
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Method 3
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Moisture content of stack gas
Method 5
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Gas MW & composition (%O2, %N2, %CO2)
Method 4
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Stack gas velocity & flow rate
total particulate emissions
Method 9
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visual determination of opacity
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Standard Methods – Gases
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Method 6
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Method 7
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Nitrogen oxides
Method 10
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Sulfur dioxide
Carbon dioxide
Other methods
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Hydrocarbons
Hydrochloric acid
Hydrogen sulfide
Fluoride
Dioxins & furans
PCBs, PAHs, Formaldehyde (HCHO),
others
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Continuous Emission
Monitoring
 Real-time detection of emissions gases
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Carbon dioxide
Nitrogen oxides
Sulfur oxides
Hydrogen chloride
Total hydrocarbons
 Real time measure of flow and temperature
 Continuous monitoring of opacity
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Continuous Emission
Monitoring cabinet
CO
NO
NOx
SO2
THCs
Flow
Temperature
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Is this something you
should do?
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Source sampling is
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Involved
Expensive
Time consuming
Source sampling requires
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Specialized training, experience & equipment
Laboratory support capacity
Significant QA/QC
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What should you be able to do?
 Know if it is being planned right
 Know if it is being done right
 Know if it is reported right
 What resources are available
 ITEP
 EPA
 CARB
 Smoke school
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What We just Covered
 Air pollutants can be controlled
 involve tradeoffs, shell game
 Different controls for different types of
pollutants
 Source sampling is regulatory requirement to
ensure facilities are operating within permit
requirements
 Source sampling usually a series of methods
 Source sampling not likely something you will do
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Animated Control
Technologies
http://www.iowadnr.gov/Environ
ment/AirQuality/HowAirPollution
IsControlled.aspx
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