Addressing Stationary Source Emission Estimation and
Inventories by the Global Oil & Gas Industry
Derek Swick and Karin Ritter Regulatory and Scientific Affairs, API, Washington DC
Jeffrey SiegellExxonMobil Research and Engineering, Fairfax, VA
Clay FreebergChevron Corporation, San Ramon, CA
Miriam Lev-OnThe LEVON Group, LLC, Thousand Oaks, CA
EPA 2008 TRI National Training Conference, 12-14 February 2008, Washington DC
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Outline Industry Operations Data Quality API Emission
Studies TRI Data Variability Emission Factors
Compilation Study Next steps
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Industry Operations
Global Oil & Gas Industry encounters unique operational and business environments;
Companies range from vertically integrated multinational companies to independent producers, refiners and marketers of petroleum products;
Technical resources and availability of site specific information varies by location and size of operations
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Call for Data Consistency The Oil&Gas Industry is subject to multiple
regulations at the federal, state and local levels
The industry desires robust data for developing emission inventories while complying with a variety of emission reporting mandates
Companies strive towards consistent, reliable, and credible methodologies to derive emission estimates to meet specific emission reporting requirements
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API’s Stationary Source Emissions Task Force
Convened in the early 1990s to coordinate all air related emissions studies at API
Scope is limited to stationary sources Led and facilitated by member company experts who
oversee field and laboratory data collection and analysis for each of the approved projects
Primary Goals:– Publish technical reports containing new emissions data– Inform membership about new emissions data availability,– Provide data to the U.S. EPA for inclusion in AP-42
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Examples of Emission Studies: Combustion Emissions
Fine Particulates– Evaluation of different PM2.5 stack testing methods and the way
condensable matter or aerosols are taken into account– Development of test plans and field tests to illustrate these differences
Trace Metals– Explore use of PM test results to confirm / update factors for trace metals
from combustion– Compare PM combustion study with existing emission factors available
from the Western States Petroleum Association (WSPA), API & EPA Sulfuric Acid
– Develop improved EFs for estimating emissions of sulfuric acid (H2SO4), and sulfur trioxide (SO3), from gas-fired refinery heaters, boilers and FCCUs
– Publish guidance for estimating H2SO4 emissions from combustion sources and work on including the results in EPA’s AP-42
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Examples of Emission Studies: Fugitive Emissions Components in Heavy Liquids (HL) Service
– Review previous test data collected by industry and provided to the U.S. EPA
– Work with the U.S. EPA to ensure acceptance of new HL emission factors that are based on previously submitted data
Polycyclic Aromatic Hydrocarbons (PAHs)– Determine appropriateness of including PAH species in
HL fugitive emissions– Assess relative contribution of specific PAH species to
HL fugitive emissions
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Examples of Emission Studies: Loading & Storage Emissions Tank Cleaning
– Develop methodology for estimating emissions from cleaning atmospheric storage tanks
Non-Freely Vented Internal Floating Roof Tanks– Develop methodology for estimating emissions from non-freely vented
internal floating roof storage tanks Surface Temperature
– Develop improved methodology for determining the impact of surface temperature on storage tank emissions estimating methodology
Marine Vessel Loading & Transit Emissions– Confirm or improve old emission factors and methods for marine vessel
loading and transit emissions– Determine average methane fraction in crude oil loading and off-
loading
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TRI Reporting Considerations TRI requires estimating quantities of chemicals
released, discharged, or otherwise managed as waste – Facilities are instructed to use the best “readily available data” – When such data are not available, “reasonable estimates”, are
deemed sufficient to fulfill reporting requirements EPA's TRI Instructions refer to four basic methods that
may be used to develop such estimates – Monitoring Data or Direct Measurement;– Mass Balance;– Emission Factors; – Other approaches, such as
• Engineering Calculations, or • Best Engineering Judgment
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Highlights of API TRI Variability Review The flexible approach allowed for TRI emission
estimating has led – in some cases - to wide variability in the estimated and reported emissions
API has reviewed refineries TRI data for 2000-2005 to try and understand the roots of the variability– API reviewed data for all of SIC 2911– Not all reporting refineries are API members
The review focused on air releases, as they make up over 80% of total releases from facilities for most chemicals
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TRI Data Source– EPA TRI public data flat file, “basic pull” format, – As provided by EPA 8/16/2007
Operable Capacity Data– Energy Information Administration (EIA)
Refinery Capacity Reports, 2001 – 2006– Atmospheric Crude Distillation, barrels per
stream day
Total Releases & Transfers & Transfers per Capacityper Capacity
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Variability of Air Releases Reported to TRI by Petroleum
Refineries Reported air release data vary widely among facilities, even when normalized by total operating capacity
Example: Sulfuric Acid Data based on “Releases to air on site”
– Total of Form R Part II Sections 5.1 (fugitive) and 5.2 (stack)
– For each year evaluated minimum, maximum, 1st and 3rd quartiles, median, mean, number of reporting facilities
Documented also the number of facilities whose reported releases seem to be outliers
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Normalized Sulfuric Acid Releases to Air
Maximum reported release– Consistently about 60 lbs/1,000 bbl from 2000 – 2004, – Decreased about 5-fold between 2004 and 2005 to 12
lbs/1,000 bbl,– The maximum in each year is about 9 – 35 times the
median. 1 – 5 % of reporting facilities are outliers in each
year Overall
– 74 facilities reported releases from 2000 – 2005,– 3 of which were outliers in at least one year.
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Sulfuric Acid Releases to AirNormalized by Total Operable
CapacityStatistic
Quantity (lbs/1,000 bbl)
2000 2001 2002 2003 2004 2005
Minimum 0.002 0.003 0.004 0.011 0.009 0.053
1st Quartile 0.601 0.526 0.646 0.802 0.762 0.567
Median 1.701 1.548 1.566 1.445 1.682 1.358
Mean 3.744 3.810 3.584 3.410 3.332 2.146
3rd Quartile 4.120 3.630 3.844 3.358 3.342 2.759
Maximum 59.361 63.927 63.927 63.927 59.361 12.329
Count 53 59 63 63 63 67
Outliers 1 2 2 3 1 1
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Findings from the API TRI Variability Review
The wide disparity in reported releases normalized by capacity suggests estimation methods may contribute to the variability
While these results were for normalized data, similar results are found for non-normalized release data
Reported releases from a relatively few facilities can significantly ‘bias’ the total emissions reported by the petroleum refining sector
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Data Quality Observations
EPA’s Guidance on Systematic Planning Using the Data Quality Objectives (DQO) Process (EPA QA/G-4, 2006), – Provides a standard working tool to develop DQOs in support of
EPA’s Quality System agency-wide– Ensures that the quantity, and quality of data are of the
appropriate type for their intended use The methodological flexibility and associated variability of TRI
data is a case in point for data being taken out of its original design parameters,– The primary goal of TRI is to increase public awareness to the
presence, releases and transfers of listed chemicals,– It was not designed to have the rigor needed for quantitative
exposure estimates,– It was not intended to be the basis for regulatory decision-making
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Rationale for TRI Emission Factors Project
The use of potentially unrepresentative emissions factors in petroleum industry operations has the potential to leading to reporting errors,– For example: BP initially reported for RY2004 – 1,938,362 lbs
of Formaldehyde– Following site specific sample data the revised amount was
102,156 lbs
– The error was due to selecting the wrong emission factor Industry reputation is at stake due to the use of
potentially unrepresentative emission factors A more cooperative sector-wide guidance approach
on best available emissions factors is desired to improve consistency and comparability of reported data.
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Compilation of Emission Estimation Methods for TRI
Reporting Guidance document designed to provide quick reference look-up tables for methods that are available for estimating emissions for reporting under the U.S. EPA TRI
Focuses on sources and operations that are prevalent in the petroleum industry, and its operating segments, that are subject to TRI reporting
Table format with appropriate methods for each air release source categories
Direct links from the compilation table where the methods are described to the authoritative references provided elaborating on the methods
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Sulfuric acid (H2SO4) Emissions from boiler and heaters
Combusting sulfur-bearing fuel assumes 100% conversion of sulfur into a distribution of SO2, SO3, and H2SO4. Information needed to calculate H2SO4 emissions are: fuel properties including sulfur content; and flue gas conditions including water concentration and stack temperature.
1. U.S.EPA, Guidance for Reporting Sulfuric Acid Aerosols (acid aerosols, including mists, vapors, gas, fog, and other airborne forms of any particle size), EPA-745-R-97-007March 1998 Revision
http://www.epa.gov/tri 2. “New Method Estimates
Sulfuric Acid Emissions from Fired Heaters", Oil & Gas Journal, 100.40, 78-80, 2002.
Excerpt Methods Compilation Tables: Combustion Devices
SOURCES METHODS REFERENCES COMBUSTION DEVICES
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Excerpt Methods Compilation Tables: Fugitive Emissions
SOURCES METHODS REFERENCES FUGUITIVE EMISSION
SOURCES
Process Components
1. USEPA has developed several approaches for estimating fugitive emissions from process components, such as valves, pumps, flanges, compressor seals and pressure release devices;
2. All of these approaches are based on VOC or TOC measurements and using compound speciation data to obtain chemical-specific information.
Relevant references for more information are:
EPA 1995 protocol with specific methods and factors for:
Average emission factors for sites that do not monitor components;
1. Average leak/no-leak factors for sites with monitoring data;
2. "Correlation Equations " to convert Method 21 PPM readings to mass emissions; and
3. Detailed instructions for the collection of site-specific screening and bagging data and control efficiencies. API augmented this guidance with
average factors for components in heavy liquid service;
API has developed new factors for optical imaging for sites with Smart LDAR.
EPA-453/R-95-017 - US EPA, Protocol for Equipment leak Emission Estimates, 1995.
http://www.epa.gov/ttn/chief/efdocs/equiplks.pdf (a) API Publication 337 - Development of Emission
Factors for Leaks in refinery Components in heavy Liquid Service.
(b) API Publication 343 - Fugitive Emissions From Equipment leaks II: Calculation Procedures for Petroleum Industry Facilities. M. Lev-On et.al, “Derivation of New Emission
Factors for Quantification of Mass Emissions when Using Optical Gas Imaging for Detecting Leaks”, Journal of the Air & Waste Management Association, September 2007, in print,
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Benefit of Emission Factors Compilation Study
The Compilation contains emission factors that are relevant to the petroleum industry
The Compilation has the potential to benefit other reporting programs, beyond TRI, as many of the chemicals are also on the hazardous air pollutants (HAPs) list
Improved emission factors and estimation methods should contribute to enhanced reporting accuracy under various Air regulations
Accurately – and credibly - characterizing emissions from industry facilities will contribute to improved public perception and community relations for industry facilities
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Next Steps API is continuing to conduct emissions
studies and is publishing results in peer reviewed journals and technical reports– Relevant data are provided to API
Standards department for inclusion in updates of standards
– Data are provided to the U.S. EPA for inclusion in AP-42
The Emission Factors Compilation study is moving to its next phase to generate specific examples on how to calculate air releases from key industry sources
New studies are being proposed during the yearly budget cycle and are considered for implementation
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Contact Information
Derek D. Swick, MPPRegulatory and Scientific Affairs
American Petroleum Institute1220 L Street, NW
Washington, D.C. 20005(202) 682-8341
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