Technical Support Document:
Limestone and Dolomite Use
(Except in Cement, Lime, and Glass Manufacturing)
Office of Air and Radiation
U.S. Environmental Protection Agency
January 22, 2009
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Contents
1. Industry Description 3
2. Total Emissions 3
3. Review of Existing Relevant Reporting Programs/Methodologies 4
3.1 2006 IPCC Guidelines for National Greenhouse Gas Inventories 4
3.2 Australian Government's National Greenhouse and Energy Reporting System 5
4. Options for Reporting Threshold 5
5. Options for Monitoring Methods 6
5.1 Option 1: Simplified Calculation Method 6
5.2 Option 2: Facility Specific Calculation 6
5.3 Option 3: Direct measurement 7
6. Options for Estimating Missing Data 8
7. QA/QC Requirements 8
8. Types of Emissions to be Reported 8
9. References 9
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1. Industry Description
As described in the Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2006 (EPA
2008), limestone (CaCOs) and dolomite (CaMg(CC>3)2) are basic raw materials used by a wide
variety of industries, including construction, agriculture, chemical, metallurgy, glass
manufacture, and environmental pollution control. Large deposits of limestone of varying sizes
and degrees of purity occur in nearly every state in the United States, and significant quantities
are extracted for industrial applications. The five leading limestone and dolomite producing
states are (in descending order of tonnage) Texas, Florida, Missouri, Pennsylvania, and
Oklahoma (USGS 2007). For some of these applications, limestone undergoes a calcination
process in which the limestone is sufficiently heated, generating CC>2 as a by-product. For
example, the calcination of pure limestone is as follows:
CaCO3 + heat -> CaO + CO2
There are a variety of emissive and non-emissive uses of limestone. Examples of such emissive
applications include limestone used as a flux or purifier in metallurgical furnaces, as a sorbent
in flue gas desulfurization systems for utility and industrial plants, and as a raw material in the
production of mineral wool or magnesium. The manufacture of cement, lime, and glass also
result in process emissions; these applications are elaborated upon elsewhere since they are
relatively significant emitters. Non-emissive applications include limestone used in poultry
grit, as asphalt filler, and in the manufacturing of paper. The most common applications of
limestone are use as a construction aggregate (78% of specified national consumption in 2006),
the chemical and metallurgy industries (18%), agricultural uses (2%) and other specialized
applications (1%) (USGS 2007). The breakdown of reported specified dolomite national
consumption was similar to that of limestone; 87% of consumption was used as a construction
aggregate, 9% was used in chemical and metallurgical applications, and 3% was used for
agricultural use (USGS 2007).
2.
Total Emissions
As estimated in the U.S. Inventory (EPA 2008), national process emissions from other
limestone and dolomite uses (i.e. excluding cement, lime, and glass manufacturing) were
7,868,068 metric tons (Mt) of CC>2 in 2006. These emissions increased 13% over the previous
year and have increased 48% since 1990. The U.S. Inventory does not specify stationary
combustion emissions for this source. Major emissive applications are presented in Table 1.
Table 1. Breakdown of 2006 COi Process Emissions by Application
Application
Flux Stone
Sulfur Oxide Removal
Other Miscellaneous Uses
TOTAL
Emissions (Mt COi)
5,072,122
2,060,545
735,401
7,868,068
Percent of Total
64%
26%
9%
100%
Source: U.S. EPA (2008) Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2006
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Facility-level information on other limestone uses is not estimated here, due to the difficulty in
obtaining this information from a wide variety of emissive applications and the myriad
associated facilities Consequently, we have not estimated either process or stationary
combustion emissions at the facility level, or conducted the subsequent threshold analysis.
3. Review of Existing Relevant Reporting Programs/Methodologies
Protocols and guidance review for this analysis include the 2006 IPCC Guidelines, U.S.
Inventory, the Technical Guidelines for the Voluntary Reporting of Greenhouses Gases
(1605(b)) Program, and the Australian National Greenhouse Gas Reporting Program. These
methodologies are all based upon the IPCC methodology of measuring the consumption of
carbonate inputs, but differ in their use of default values. These values are based on differing
assumptions of the carbonate weight fraction in process inputs; for example, the IPCC Tier 1
and 2 assume that carbonate inputs are 95% pure (i.e., 95% of the mass consumed is
carbonate), whereas the Australian Program assumes a default purity of 90% for limestone,
95% for dolomite, and 100% for magnesium carbonate (Australian DCC 2007, IPCC 2006).
3.1 2006 IPCC Guidelines for National Greenhouse Gas Inventories
The IPCC considers three tiers of consumption-based methodologies that differ in their
assumptions of the types of carbonates consumed. Specifically, the Tier 1 and 2 methods
assume that only limestone and dolomite are used as carbonate inputs. In addition, the Tier 1
method assumes a default limestone versus dolomite consumption fraction. The Tier 1
equation is as follows:
EC02 = Mc • (0.85 EFLS + 0.15 EFD)
Where:
Eco2 = process emissions of CC>2 (Mt)
Mc = mass of carbonate consumed (Mt)
= emission factor for limestone (Mt CC>2 / Mt limestone)
= emission factor for dolomite (Mt CC>2 / Mt dolomite)
The Tier 2 method is the same as the Tier 1 method, except that the fraction of limestone
versus dolomite consumed is not a default value. The calculation is as follows:
EC02 = (MLS ' EFLS) + (MD • EFD)
Where:
Eco2 = process emissions of CC>2 (Mt)
MLS = mass of limestone consumed (Mt)
£FLS = emission factor for limestone (Mt CC>2 / Mt limestone)
MD = mass of dolomite consumed (Mt)
EFD = emission factor for dolomite (Mt CC>2 / Mt dolomite)
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IPCC also considers a Tier 3 method, which does not assume a specific type(s) of carbonate
input. This approach requires facilities to conduct a chemical analysis to determine the weight
fraction of carbonates in their inputs, and then apply this information to the product of the
stoichiometric emission factors and the fraction of calcination achieved. In other words:
EC02 = I, (Mi
Where:
Eco2 = process emissions of CO2 (Mt)
M; = mass of carbonate / consumed (Mt)
EF; = emission factor for carbonate /' (Mt CO2 / Mt carbonate)
F; = fraction of calcination achieved for carbonate /', fraction
Emission factors for common carbonates are presented in Table 2.
Table 2. COi Emission Factors for Common Carbonates
Mineral Name - Carbonate
Calcite/aragonite - CaCO3
Magnesite - MgCO3
Dolomite - CaMg(CO3)2
Siderite - FeCO3
Ankerite - Ca(Fe,Mg,Mn)(CO3)2
Rhodochrosite - MnCO3
Sodium Carbonate/Soda Ash - Na2CO3
COi Emission Factor
(tons COi/ton carbonate)
0.43971
0.52197
0.47732
0.37987
0.40822-0.47572
0.38286
0.41492
Source: IPCC (2006) 2006 IPCC Guidelines for National Greenhouse Gas Inventories
3.2 Australian Government's National Greenhouse and Energy Reporting System
The Australian Government's National Greenhouse and Energy Reporting System require
reporting of CO2 emissions from other uses of carbonates. Registration and reporting under this
system is required for corporations if: they control facilities that emit at least 25,000 Mt of
CO2e, or produce or consume at least 100 terajoules of energy; or their corporate group emits
at least 125,000 Mt CO2e, or it produces or consumes at least 500 terajoules of energy
(Australian DCC 2007). The higher-order method used for estimating emissions from other
limestone uses is the IPCC Tier 3 method, albeit with emission factors in three significant
figures instead of five as used by the IPCC.
4. Options for Reporting Threshold
Thresholds of 1,000, 10,000, 25,000, and 100,000 Mt of CO2 were considered, as well as
inclusion of all facilities (i.e., 100% of facilities).
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Despite the relatively small amount of CO2 emissions generated by other applications of
limestone (less than 3% of total national process emissions from industrial processes1), a
threshold is considered feasible because of the straightforward associated emissions estimation
methodology. This methodology, which is based on measuring the consumption of carbonate
inputs, is simple, widely accepted among existing protocols, and is relatively certain since it is
based upon stoichiometry. The 25,000 metric ton threshold was chosen to reduce the
compliance burden on small businesses, which are likely not consuming these carbonates (and
thus emitting CO2) in quantities large enough to justify the cost of compliance. In addition, the
multiple emissive and non-emissive uses of these carbonates may create confusion over which
facilities are required to report. Because of the wide variety of emissive applications, a
facility-specific threshold analysis of emissions has not yet been conducted.
5. Options for Monitoring Methods
As previously stated, existing methodologies for estimating emissions from other limestone
and dolomite uses are generally simply, easy to implement, and coalesce around the IPCC
guidelines, but differ in their assumption of carbonate input types. Specifically, Tier 1 and 2
assume only limestone and dolomite are used as inputs and are 95% pure. A Tier 3
methodology requires facility specific information. Application of this methodology requires
facilities to conduct a chemical analysis to determine the weight fraction of carbonates in their
raw materials, a relatively simple additional requirement. The uncertainty involved in using the
more exact Tier 3 methodology is 1-3 % (IPCC 2006). IPCC does not provide the uncertainty
associated with using a Tier 1 or 2 methodology for estimating emissions from other limestone
and dolomite uses, but does estimate that the uncertainty is as high as 60% for other mineral
applications (e.g., glass manufacture) that require similar assumptions in input purity.
The discussion below outlines the specific monitoring methods considered for this technical
support document: a simplified emission calculation (Option 1), a facility specific calculation
(Option 2), and direct measurement (Option 3). All of these options require annual reporting
and require each facility to internally develop the methodology and monitoring plan for
calculating emissions from other limestone and dolomite uses. For reporting options for
stationary combustion emissions (CO2, N2O, and CH4), refer to EPA-HQ-OAR-2008-0508-
004.
5.1 Option 1: Simplified Calculation Method
Option 1 follows the IPCC's Tier 1 protocol. The Tier 1 monitoring method uses default values
for both the emission factors and the relative consumption of limestone and dolomite, as
previously detailed in section 3.1.
5.2 Option 2: Facility Specific Calculation
This option is similar to the IPCC Tier 3 method. In order to successfully implement this
methodology, a reporting facility will need to know the mass of each carbonate consumed. It is
1 As estimated in the U.S. Inventory (EPA 2008), total 2006 process emissions from industrial processes were
320.9 Tg CO2 equivalent; process emissions from other limestone uses were 7.87 Tg CO2 equivalent.
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assumed that a facility will need to send samples of each carbonate consumed to an off-site
laboratory for a chemical analysis of the carbonate weight fraction. Emission factors are based
on stoichiometry and are presented in Table 2. The methodology for calculating the fraction of
calcination achieved can be determined based on sampling and analysis conducted by a
certified laboratory using a suitable method such as an x-ray fluorescence test or other
enhanced testing method published by a consensus standards organization (e.g., ASTM,
ASME, API). The more detailed (i.e., Tier 3) methodology has a relatively low uncertainty
and a minimal additional reporting burden compared to other methods.
The Tier 3 monitoring method involves the aforementioned facility-level calculation and
sampling on an annual basis, at minimum. This method involves the following steps:
• Facility managers review samples of the carbonate input annually.
• Each facility sends samples of their inputs to an off-site laboratory, in order to conduct
an analysis of the carbonate weight fraction. A facility is assumed to need to analyze, at
most, seven types of input, one for each of the common carbonates listed in Table 2.
5.3 Option 3: Direct measurement
In facilities where process emissions and/or combustion GHG emissions are contained within a
stack or vent, direct measurement constitutes either measurements of the individual GHG
concentration in the stack gas and the flow rate of the stack gas using a Continuous Emissions
Monitoring System (CEMS), or periodic measurement of the individual GHG concentration in
the stack gas and the flow rate of the stack gas using periodic stack testing. Under either a
CEMS approach or a stack testing approach, the emissions measurement data would be
reported annually. Given the diverse set of industries that use carbonates, it is not possible to
assume clearly whether both process and combustion related CC>2 emissions would be emitted
through a single stack.
Elements of a CEMS include a platform and sample probe within the stack to withdraw a
sample of the stack gas, an analyzer to measure the concentration of each GHG pollutant (e.g.,
CC>2) in the stack gas, and a flow meter within the stack to measure the flow rate of the stack
gas. The emissions are calculated from the concentration of the specific GHG pollutant in the
stack gas that is monitored using the concentration monitor for that pollutant and the flow rate
of the stack gas. The CEMS continuously withdraws and analyzes a sample of the stack gas
and continuously measures each of the individual GHG pollutant concentration and flow rate
of the stack gas.
For direct measurement using stack testing, sampling equipment would be periodically brought
to the site and installed temporarily in the stack to withdraw a sample of the stack gas and
measure the flow rate of the stack gas. Similar to CEMS, for stack testing the emissions are
calculated from the concentration of GHGs in the stack gas and the flow rate of the stack gas.
The difference between stack testing and continuous monitoring is that the CEMS data provide
a continuous measurement of the emissions while a stack test provides a periodic measurement
of the emissions. Stack testing could also capture both process and combustion relation CC>2
combustion related emissions.
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6. Options for Estimating Missing Data
Options and considerations for missing data vary will vary depending on the proposed
monitoring method. Each option would require a complete record of all measured parameters
as well as parameters determined from company records that are used in the GHG emissions
calculations (e.g., carbonate consumption).
In the occasion that a facility lacks carbonate input data for a certain time period, that facility
would apply their typical mix of carbonates consumed by mass during times of known data to
the period of missing data. However, the likelihood for missing data is low, as businesses
closely track their purchase of production inputs.
For Option 2, if the results of the chemical analysis on the calcination fraction of carbonates
consumed were lost or missing, the analysis would have to be repeated. For units using direct
measurement to measure CO2 emissions, the equipment would be tested for accuracy and
calibrated as necessary by a certified third party vendor. These procedures would be consistent
in stringency and data reporting and documentation adequacy with the quality assurance
procedures for CEMS described in Part 75 of the Acid Rain Program.
7. QA/QC Requirements
Facilities would conduct quality assurance and quality control (QA/QC) of the production and
consumption data, and emission estimates reported. Specific QA/QC requirements will vary
depending on the monitoring methods, but facilities would prepare an in-depth QA/QC plan
which would include checks on production data (quantities of carbonates consumed, by type),
the calcination fraction information received from the lab analysis, and calculations performed
to estimate GHG emissions.
In order to ensure accurate emissions estimates, a facility could compare emissions estimates
using the proposed (i.e., Tier 3) methodology to the IPCC Tier 1 and 2 approaches. The facility
could also track its carbonate consumption and emissions over time.
8. Types of Emissions to be Reported
To ensure completeness, facility owners or operators would report annual GHG emissions
from other carbonate uses, including both combustion-related (CO2, CH4, and N2O) emissions
and process-related CO2 emissions. For reporting options for stationary combustion refer to
EPA-HQ-OAR-2008-0508-004.
Along with their formal report, facilities would submit carbonate consumption data (in metric
tons, by carbonate), the fraction of calcination achieved (for each carbonate), and the average
annual mass fraction of carbonate-based mineral in carbonate-based raw material by carbonate
type (i.e., the average annual quantity of carbonate (COs) in the raw material either based on
stoichiometric analysis or measurement).
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9. References
Australian DCC (2007). National Greenhouse and Energy Reporting System: Technical
Guidelines for the Estimation of Greenhouse Emissions and Energy at Facility Level.
Commonwealth of Australia. Canberra, Australia.
http://www.climatechange.gov.au/reporting/guidelines/
IPCC (2006) 2006IPCC Guidelines for National Greenhouse Gas Inventories. The National
Greenhouse Gas Inventories Programme, The Intergovernmental Panel on Climate Change,
H.S. Eggleston, L. Buenida, K. Miwa, T Ngara, and K. Tanabe (eds.). Hayama, Kanagawa,
Japan, http://www.ipcc-nggip.iges.or.jp/public/2006gl/index.html
U.S. EPA (200$) Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2006. U.S.
Environmental Protection Agency, Washington D.C. USEPA #430-R-08-005.
http://www.epa.gov/climatechange/emissions/usinventoryreport.htmltf
USGS (2007) Minerals Yearbook: Crushed Stone Annual Report. U.S. Geological Survey,
Reston, VA. http://minerals.usgs.gOv/minerals/pubs/commodity/stonej:mshed/myb 1-2006-
stonc.pdf
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