Post on 16-Dec-2015
description
Source Emissions Testing and Emissions Specialists
Kevin DonahoeKevin DonahoeThe Avogadro Group, LLC
PNWIS November 8 2012PNWIS November 8, 2012Portland, Oregon
Key Points
y What is particulate matter?
y What are we trying to measure?
y Methodology and Results
y Conclusions and Implications
TAKE NOTE
y A POLLUTANT IS NOT DEFINED BY THE CHEMICAL OR PHYSICAL CHARACTERISTICS OF THE POLLUTANT (e g PHYSICAL CHARACTERISTICS OF THE POLLUTANT (e.g. PM2.5, CPM)
y IT IS DEFINED BY THE SAMPLING METHODOLOGY USED TO COLLECT THE POLLUTANT (and the sampler?)
What is Particulate Matter?
y Primary Particulatey Filterable PM (primary front half)Filterable PM (primary front half)
y Solid or liquid material at stack conditions TSP, PM10 , & PM2.5y Methodology well-established no problems
y Condensable PM (primary back half)Vapor or gas at stack conditionsy Vapor or gas at stack conditions
y Condenses and/or reacts upon cooling and dilution in ambient air to form solid or liquid PM immediately after stack discharge
y Precursors are organic and inorganicy Common measurement bias involves inorganic (e.g. ammonia and SO2)g ( g 2)y All assumed to be in the PM2.5 size fractiony Source testing methods attempt to duplicate complicated formation process
y Secondary Particulateyy Forms by chemical reactions in atmosphere downstream of
release point, but not immediately
y Question: Can we separate the two?y Question: Can we separate the two?
What is Particulate Matter?
ParticulatePrimarySecondary PrimarySecondary
Condensable FilterableTSPTSP
PM10PM10PM2.5
What is Particulate Matter?
ParticulatePrimarySecondary PrimarySecondary
Condensable FilterableTSPTSP
PM10A h d
PM10PM2.5
EPAMethod5TestSourceTest
What is Particulate Matter?
ParticulatePrimarySecondary PrimarySecondary
Condensable FilterableTSPTSP
PM10A h d /
PM10PM2.5
EPAMethod5/202SourceTest
What is Particulate Matter?
ParticulatePrimarySecondary PrimarySecondary
Condensable FilterableTSPTSP
PM10h d
PM10PM2.5
EPAMethod201A/202SourceTest
What is Particulate Matter?
ParticulatePrimarySecondary PrimarySecondary
Condensable FilterableTSPTSP
PM10b l
PM10PM2.5
AmbientSamplerBasisforNAAQS
What are we trying to measure?
Primary PM2.5 Emissions- Particles
Photochemistry other Gases (precursors) to Secondary PM2.5 and to smog (ozone, etc.)
P GSP
PC
P
smog
- Some Gases form Condensable PMg ( , )
G
Gsmog
G SGC
C
GCP G
CP
Ambient MonitorUnder stack conditions
SSGGSGS
SC
C
PG
PG
Ambient MonitorCollectsParticles,Condensables &S d
Under stack conditionsWe measureParticles & GasesP Secondary
Primary PM2.5 Emissions- Particles (solid, liquid)
G GG
- Condensables
Old EPA 202 Test Method
Old EPA 202 Test Method
Why Old EPA 202 is problematicy Does not accurately emulate stack releasey Gases bubbled through water dissolved into g
solutiony Dissolved gases form salts that may or may not form
naturally when released to atmospherenaturally when released to atmospherey Although some back-half PM may actually be CPM or
primary PM2.5 emissions, much can be an artifact of the methodmethod
y Nitrogen purge works very well for high SO2sources but is only optional!sources but is only optional!
y Other optional analytical procedures varied results between sources/testersresults between sources/testers
New Dry 202 (formerly OTM-028)( d d i i d b k filt )(uses condenser, dry impingers and backup filter)
New Dry 202 (formerly OTM-028)
New Dry Method 202 (OTM-028) y Objectives
y Less artifacty Fewer variables (eliminate options)e e a ab es (e ate opt o s)y More consistent results
y Procedural Changesy Water insulated condenser coily Water-insulated condenser coily First impinger is short-stem dropout varietyy First two impingers are dry at beginning of test run
o Condenser and impingers cool sample to 85 F or lowerp g po Gas does not bubble through excess water or condensateo Condensables recovered from coil, dry impingers and CPM filter
y CPM filter added after 2nd impingerM d i di l d SOy Mandatory nitrogen purge to remove dissolved SO2
y Impingers after filter are not recovered (moisture content only)y Extraction solvent - MeCl2 is replaced with hexaney Glassware is bakedy Glassware is baked
Early Tests: OTM-028CPM emissions by EPA 202 and OTM-028
Logarithmic Scale
0.100
0 010
0.100
/
M
M
B
t
u
EPA 202
OTM 0280.010
s
s
i
o
n
r
a
t
e
,
l
b
/
Pow er(EPA 202)
0.001
C
P
M
e
m
i
s
Pow er(OTM 028)
0.0000.1 1 10 100
SO2 concentration, ppm vol dry
These are results from a variety of sources, 2007 to 2009 with trend lines for each of the two methods. OTM-028 (draft 202) results were higher than Old 202 for low-emitting sources with low SO2.
More Recent Dry Impinger ResultsCPM emissions by EPA Old 202 and New 202
Linear Scale, vs. SO2
0.025
0.030
M
M
B
t
u
Old 202
0.015
0.020
n
r
a
t
e
,
l
b
/
M
New 202
Linear (Old 202)
0.000
0.005
0.010
e
m
i
s
s
i
o
n
These are results from 2010 and 2011 distributed according to SO2. The
0.0000 5 10 15 20
C
P
M
e
SO2 concentration, ppm vol dry
g 2New and Old 202 gave similar results and neither trended with SO2. There are results around 0.010 and around 0.001 throughout the range.
CPM Emissions by Old and New EPA 202Gas-Fired Plants Only
0.0018
Gas Fired Plants OnlyOld 202 New 202 Linear (Old 202) Linear (New 202)
0 0012
0.0014
0.0016
M
B
t
u
0 0006
0.0008
0.001
0.0012
C
P
M
l
b
/
M
M
0
0.0002
0.0004
0.0006
00 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45
SO2 Concentration, ppm vol dry
Datafromjustgasfired boilersandgasturbines;someoftheSO2concentrationsshownareestimated.LittledifferenceOld/NewMethod.
CPM vs. vs. SO2
CPM vs.
NH3NH3
Is the new method better?y Did EPA meet its objectives?
y Results seem less variabley Less artifact at high SO sources; inconclusive at low SO sourcesy Less artifact at high SO2 sources; inconclusive at low SO2 sourcesy More recovery fractions add potential for contamination or bias
y Can we improve the situation?py Improve blank levels, update lab proceduresy More fractions add complication to analysis
y Reduce Ammonia Slip (below about 2 ppm)p ( pp )y Correct the results for ammonium saltsy some have suggested using controlled condensation test results for the
inorganic fractiony Use a Dilution method (measure filterable and condensable
together)y EPA conditional test method CTM-039
ASTM dil i h d y ASTM dilution method
Dilution Sampler ConceptStack emissions of Primary PM2.5Emissions into a "virtual" stream of air
PhotochemistryParticles Secondary + Primary PM2.5+ Condensables
Stream of air + Gases
Ambient sampler PM2.5 filter
Stack sampling of Primary PM2.5 by CTM-039Sample "emitted" into a stream of air
Primary PM2.5 - Particles and Condensables (and Gases)
Sampled through filtersame as Ambient sampler
Stream of air Gases remain as gases, no secondary PM2.5
CTM-039
y Designed to emulate dilution of stack emissions in gambient air
y Condensables form in the same way as in actual y Condensables form in the same way as in actual emissions EPAs Gold Standard
P i PM2 5 ti l d CPM ll l d y Primary PM2.5 particles and CPM - all sampled together no secondary collection
y Shows promise the results of comparative studies are encouraging
y Disadvantage: New, Rare, Expensive, Bulky
l f / ( ) b h l l bl k l l l d f l hAresultof1mg/m3(CCGT)isaboutthesamelevelasablanksample.BoilersweresolidfuelwithSNCR.BoilerAwastestedoncebyNew202withtheammoniainjectionoff.CTM039canreduceartifactandthereforeprovidelowerresultsinsomecases.
Conclusionsy The new method is advantageous only in certain cases, usually at higher
concentrations of SO2 or other CPM precursor gases
y New 202 is sometimes only a slight improvement from the Old 202 for low-concentration sources
y New 202 might not be worth its extra cost- except in some cases (sometimes every little bit helps)
Oth lt ti ( h CTM 039) ill t b t id y Other alternatives (such as CTM-039) will cost even more - but may provide more representative results for some cases
y Results will depend on which gases are present (NH SO SO HCl) and in y Results will depend on which gases are present (NH3, SO2, SO3, HCl) and in what relative concentrations
y The Method used will define the Resultsy The Method used will define the Results
y Quality Testing is critical!
Questions?
Kevin DonahoeKevin DonahoeDistrict Manager, Portland
Source Emissions Testing and Emissions SpecialistsSource Emissions Testing and Emissions SpecialistsPortland, OR Phoenix, AZ - Antioch, California Medford, OR