Post on 01-Apr-2015
transcript
Improving the Emissions Inventory
Brad Toups, Manager
Industrial Emissions Assessment
August 12, 2004
Regulatory Forum
TexAQS 2000
• The 2000 Texas Air Quality Study provided new insights into factors affecting air quality, including:– Better understanding of plume
characteristics…
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TexAQS 2000
The 2000 Texas Air Quality Study provided new insights into factors affecting air quality, including:– Better understanding of plume characteristics– Better understanding about NOx and
VOCs on Ozone Formation…
Ozone Formation
• Ozone is produced faster and yields more in Houston than in other cities.
– The rapid formation and high ozone yield occur in the industrial plumes downwind of petrochemical facilities.
– Formation rates and yield downwind of the power plants and the city core are comparable to other cities.
TCEQ/TAD BreitenbachMichael Trainer
VOC Measurements
• The VOC concentrations in Houston are very different from other cities.
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– Ethylene concentrations in Houston are much higher than in other cities.
– Ethylene is a highly reactive VOC produced in petrochemical facilities as an intermediate product in plastics production.
– Other highly reactive VOCs such as Ethylene, propylene, Butene and Butadiene are also produced in Houston.
Ethylene Distributions – Log Scale
1.0
2.5
5
10
20
40
60
80
90
95
98.0
Pe
rce
nt o
f Me
asu
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0.1 1 10
Ethylene (ppbv)
HoustonDallasNashvilleAtlanta
99.9
• The Maximum ethylene levels are an order of magnitude or more higher in Houston
• The ethylene distribution in Houston is approximately log-normal, suggesting continuous emissions.
• Ethylene emissions are definitely not Bimodal; there is no evidence to suggest two separable populations (upsets)
Parrish, 2002
TexAQS 2000
The 2000 Texas Air Quality Study provided new insights into factors affecting air quality, including:– A better understanding of plume characteristics– A better understanding about NOx and VOCs
on ozone formation– That there is more VOC in the atmosphere
than can be accounted for in the Inventory…
Inferred vs Reported Olefin Emissions
0 10 20 30 40 50
West Ship Channel 2
West Ship Channel 1
West Central Ship Channel
East Central Ship Channel
East Ship Channel
Baytown
Channelview
Mont Belvieu
Bayport
Olefin Emissions (Tons/Day)Reported Emissions Inferred Emissions
12.93
2.2
1.8
14.06
5.8
7.5
2.3
1.2
2.1
Ratio
Inferred vs Reported Olefin Emissions
Based upon Auto GC Data
Estes
Ratio
VOC Emissions
• Actual VOC emissions are much greater than reported in the Emissions Inventory
– Aircraft measurements of VOC and NOx indicate that VOC concentrations are up to an order of magnitude larger than inventory reported emissions.
– High VOC concentrations occur 40-60% of the time in industrial areas, indicating that these VOC releases are not rare occurrences, but relatively frequent events.
– Either upsets are much more frequent than reported, or there are far more leaks than currently estimated.
TexAQS 2000
The 2000 Texas Air Quality Study provided new insights into factors affecting air quality, including:– A better understanding of plume characteristics– A better understanding about NOx and VOCs
on ozone formation– That there is more VOC in the atmosphere than
can be accounted for in the Inventory
Adjusted VOCs Generate More Ozone and Improve Model Performance
Box model with adjusted ratios of ethylene and propylene to NOx reproduces the ozone measured by the aircraft quite well
Trainer, 2001
Why do we need to improve the Emissions Inventory?
• We need to put the correct meteorological data and correct emissions data into the model
• So the model can give us the right answers
for the right reasons
• So we can develop effective policies
to control ozone
Inventory Improvement GoalsAccuracy and Completeness
• Correct census of sources
• Location and physical characteristics of the Facility, Control Device, Emission Point
• Chemical speciation under all conditions
• Chemical quantification under all conditions
Complete Census
• Working towards a database to capture allowable emissions from all authorization mechanisms
Physical Characteristics of FIN, CIN, EPN
Physical Characteristics (con’t)
Before aerial photo
After Aerial Photo
Inferred vs Reported Olefin Emissions
0 10 20 30 40 50
West Ship Channel 2
West Ship Channel 1
West Central Ship Channel
East Central Ship Channel
East Ship Channel
Baytown
Channelview
Mont Belvieu
Bayport
Olefin Emissions (Tons/Day)Reported Emissions Inferred Emissions
12.93
2.2
1.8
14.06
5.8
7.5
2.3
1.2
2.1
Ratio
Inferred vs Reported Olefin Emissions
Based upon Auto GC Data
Estes
Ratio
Inventory Improvement GoalsAccuracy and Completeness
• Correct census of sources
• Location and physical characteristics of the Facility, Control Device, Emission Point
• Chemical speciation under all conditions
• Chemical quantification under all conditions
Chemical speciation under all conditions
• Developing Statistical Tools to:– identify mix and proporation of contaminants per SCC
• Matching Permit Representations with respect to speciation
• We have and continue to require the most accurate, up to date assessment techniques
• Integrating Emissions Events information into EI reviews
Inventory Improvement GoalsAccuracy and Completeness
• Correct census of sources
• Location and physical characteristics of the Facility, Control Device, Emission Point
• Chemical speciation under all conditions
• Chemical quantification under all conditions
Chemical quantification under all conditions
• Particularly with VOCs,– Some VOC components (like ethylene) are highly
reactive, others contribute less to ozone formation
– We need measurements of the composition of the VOC emissions from various industrial processes.
• Will continue to challenge inappropriate use of emissions factors when better information is available
• Will insist on consistency with EI Guidelines
Potentially Underreported Sources
• Focus on VOCs:
– Fugatives– Cooling Towers– Flares– Wastewater Systems
Risk Based Approach
• Statistical Tool development– Will continue to develop more tools to identify
discrepancies in reported data
• Risk Based closer review of selected sites
• Appropriate enforcement to encourage Responsible Official to assure reported emissions are accurate and complete
Emissions Inventory Improvements
• Benefits:– Form a solid foundation for air quality planning– Help to characterize rule effectiveness for
controlling emissions– Provide increased assurance to the Public about
sources of emissions and emissions trends– Provide a sound basis for emissions fee
assessments– Reduce reliance on ‘factors’ in modeling
Resources
• Emissions Inventory Rules and Guidance– http://www.tnrcc.state.tx.us/air/aqp/psei.html
• Emissions Inventory Helpline– 512 239-1773
• TexAQS Study Information– http://www.utexas.edu/research/ceer/texaqsarchive/
accelerated.htm