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 for
control of 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 high-velocity
gas stream shearing liquid at throat
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Venturi Scrubber
 High intensity contact between water and gas => high
pressure drop
 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
 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
 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
 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
Sources 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 the Process
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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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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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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
VOCs
 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
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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
 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
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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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