Technical Support Document for the Zinc Production Sector: Proposed Rule for Mandatory Reporting of Greenhouse Gases


Technical Support Document for the
Zinc Production Sector: Proposed Rule for
Mandatory Reporting of Greenhouse Gases

Office of Air and Radiation
U.S. Environmental Protection Agency

January 22, 2009

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Technical Support Document for the Zinc Production Sector: Proposed Rule for Mandatory Reporting of

Greenhouse Gases

CONTENTS

1.	Industry Description	1

2.	Total Emissions	3

2.1	Process Emissions	3

2.2	Combustion Emissions	3

3.	Review of Existing Programs and Methodologies	4

3.1	2006 IPCC Guidelines	4

3.2	Australian National Government's Greenhouse and Energy Reporting Program	5

3.3	Canadian Mandatory Greenhouse Gas Reporting Program	6

3.4	U.S. EPA's Inventory of U.S. Greenhouse Gas Emissions and Sinks	6

4.	Options for Reporting Threshold	7

4.1	Options Considered	7

4.2	Emissions and Facilities Covered Per Option	7

4.2.1	Process Emissions	7

4.2.2	Combustion Emissions	10

4.2.3	Emissions Thresholds	11

5.	Options for Monitoring Methods	12

5.1	Option 1: Simplified Emission Calculation	12

5.2	Option 2: Facility-Specific Calculations	12

5.3	Option 3: Direct Measurement (Annual Reporting)	13

5.3.1	Continuous Emissions Monitoring	13

5.3.2	Stacktesting	13

6.	Options for Estimating Missing Data	14

6.1	Procedures for Option 1: Simplified Emission Calculation	14

6.2	Procedures for Option 2: Facility-Specific Calculations	14

6.3	Procedures for Option 3: Direct Measurement	14

6.3.1	Continuous Emission Monitoring Data (CEMS)	14

6.3.2	Stack Testing Data	15

7.	QA/QC Requirements	16

7.1	Combustion Emissions	16

7.2	Facilities Using CEMS for Direct Measurement of Process Emissions	16

7.3	Equipment Maintenance	16

7.4	Data Management	16

8.	Types of Emissions to be Reported	18

8.1 Additional Data to be Retained Onsite	18

9.	References	19

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Technical Support Document for the Zinc Production Sector: Proposed Rule for Mandatory Reporting of

Greenhouse Gases

1. Industry Description

Zinc is a metal used as corrosion-protection coating on steel (galvanized metal), as die castings,
as an alloying metal with copper to make brass, and as chemical compounds in rubber, ceramics,
paints, and agriculture. For this proposed rule, EPA is defining the zinc production source
category to consist of zinc smelters using pyrometallurgical processes and secondary zinc
recycling facilities. Zinc smelters can process zinc sulfide ore concentrates (primary zinc
smelters) or zinc-bearing recycled and scrap materials (secondary zinc smelters). A secondary
zinc recycling facility recovers zinc from zinc-bearing recycled and scrap materials to produce
crude zinc oxide for use as a feed material to zinc smelters. Many of these secondary zinc
recycling facilities have been built specifically to process dust collected from electric arc furnace
(EAF) operations at steel mini-mills across the country.

There are no process emissive primary zinc smelters in the United States that use
pyrometallurgical processes. The one operating U.S. pyrometallurgical zinc smelter processes
secondary materials, and is therefore classified as a secondary producer (Horsehead Holding
Corporation 2007).

Secondary zinc recycling facilities operating in the U.S. use either of two thermal processes to
recover zinc from recycled EAF dust and other scrap materials. For the Waelz kiln process, the
feed material is charged to an inclined rotary kiln together with petroleum coke, metallurgical
coke, or anthracite coal. The zinc oxides in the gases from the kiln are then collected in a
baghouse or electrostatic precipitator. The second recovery process used for EAF dust uses a
flame reactor to form vaporized zinc that is subsequently captured in a vacuum condenser. The
crude zinc oxide produced at secondary zinc recycling facilities is shipped to a zinc smelter for
further processing.

In 2006, total U.S. primary and secondary production of zinc was 510,000 metric tons. Of this,
primary production methods accounted for 113,000 metric tons, and secondary zinc production
methods accounted for 397,000 metric tons (mt). Three companies contributed to this production
with a total of 9 plants in the U. S as presented in Table 1.

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Technical Support Document for the Zinc Production Sector: Proposed Rule for Mandatory Reporting of

Greenhouse Gases

Table 1. U.S. Zinc Production Facilities

Company

Facility Location

Zinc Production
Process

Process
Emissive

Horsehead Corp.

Monaca, PAa

Electrothermic
furnaces

Calumet, II

Waelz kilns

Palmerton, PA

Waelz kilns

Rockwood, TNC

Waelz kilns

Beaumont, TX

Flame reactor

Bartlesville, OK

Hydrometallurgical
recovery

Nyrstar NV

Clarksville, TN

Electrolytic

Votorantim Metals

Coldwater, Ml

Batch retorts

Houston, TX

Pinto process

A While the Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 2006 says that the
Monaca, PA facility is shut down, our research shows that it is operational (Personal
Communication 2008).

b2006 IPCC Guidelines for National Greenhouse Gas Inventories provides no emission factor for
the Electrothermic process. Instead the Guidelines give, "Unknown". However, based on the
primary role that this facility plays in producing Horsehead Holding Corporation's zinc as well as
information gathered from The Zinc Handbook: Properties, Processing, and Use in Design, this
facility is assumed to be process emissive.

This facility added a kiln in December 2007(Reuters 2008). This added capacity is not taken
into account in the process emissions Inventory of U.S. Greenhouse Gas Emissions and Sinks:
1990 - 2006. Therefore, these emissions are not taken into account in this analysis.

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Technical Support Document for the Zinc Production Sector: Proposed Rule for Mandatory Reporting of

Greenhouse Gases

2. Total Emissions

Zinc production results in combustion and process-related GHG emissions.

Total nationwide GHG emissions from zinc production in the United States were estimated to be
approximately 851,708 metric tons CO2 equivalent (mtCC^e) in 2006. This total GHG emissions
estimate includes both process-related emissions (CO2 and CH4) resulting from zinc production
operations at the 4 facilities identified as process emissive in Table 1, and combustion emissions
(CO2, CH4) from all 9 facilities.1 Process-related GHG emissions were 528,777 mtCC^e (62
percent of the total emissions). The remaining 322,931 mtCC^e emissions (38 percent of the
total emissions) were combustion GHG emissions.

2.1 Process Emissions

The major sources of GHG emissions from a zinc production facility are the process-related
emissions from the operation of electrothermic furnaces at zinc smelters and Waelz kilns at
secondary zinc recycling facilities. In an electrothermic furnace, reduction of zinc oxide using
carbon provided by the charging of coke to the furnace produces CO2. In the Waelz kiln, the zinc
feed materials are heated to approximately 1200°C in the presence of carbon producing zinc
vapor and carbon monoxide (CO). When combined with the surplus of air in the kiln, the zinc
vapors are oxidized to form crude zinc oxide, and the CO oxidized to form CO2.

2.2 Combustion Emissions

Waelz kilns release combustion emissions (CO2, CH4, and N2O) in addition to process emission
as a result of burning natural gas or other fossil fuels to produce heat for the process. For other
metallurgical process equipment used at zinc production facilities, the only source of carbon is
the natural gas or other fuel burned in the unit to produce heat for drying, melting, or casting
operations. These types of combustion emissions sources can include flame reactors, fuel-fired
furnaces, calcining kilns, dryers, casting machines, boilers, and space heaters depending on the
specific processes used at a given facility.

1 As noted above, Horsehead Holding Corporation's Rockwood, TN facility added a kiln in
December 2007. This added capacity is not taken into account in the process emissions
Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 2006.

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Technical Support Document for the Zinc Production Sector: Proposed Rule for Mandatory Reporting of

Greenhouse Gases

3. Review of Existing Programs and Methodologies

Four reporting programs and guidelines were reviewed including: the Canadian Mandatory
Greenhouse Gas Reporting Program, the Australian National Greenhouse Gas Reporting
Program, the U.S. Greenhouse Gas Inventory protocol, and the 2006 IPCC Guidelines for
National Greenhouse Gas Inventories. In general, the methodologies used for facility level
reporting coalesce around the IPCC's guidelines.

3.1 2006 IPCC Guidelines

IPCC has 3 tiers of methods used to estimate process-related CO2 emissions. The Tier 1 method
uses a default emission factor per unit of output multiplied by national production activity data.
IPCC offers two equations for calculation. The first utilizes a general default emission factor per
unit output of zinc using any process. The second utilizes default emission factors specific to
production processes - electrothermic distillation, Imperial Smelting Furnace, or Waelz Kiln
(IPCC 2006). The 2 Tier 1 IPCC methodological equations are as follows:

ECO2 — Zn X EF default

Where:

Eco2 = CO2 emissions from zinc production, metric tonne

Zn = quantity of zinc produced, metric tonne

Edefauit = default emission factor, Mt C02/Mt zinc produced

ECo2 = ET x EF et + PM x EF PM + WK x EF Wk

Where:

Eco2 = CO2 emissions from zinc production, metric tonne

ET = Quantity of zinc produced by electrothermic distillation, metric tonne

EFet = Emission factor for electrothermic distillation, mt CCVmt zinc produced

PM = Quantity of zinc produced by Imperial Smelting Furnace Process

EFpm = Emission factor for Imperial Smelting Furnace Process, mt CCVmt zinc produced

WK = Quantity of zinc produced by Waelz Kiln process, metric tonne

EFwk = Emission factor for Waelz Kiln process, mt CCVmt zinc produced.

IPCC's Tier 2 method calculates process-related emissions using country specific emission
factors based on aggregated plant statistics for the use of reducing agents, furnace types and
other process materials. Default emission factors are applied to each material. This method is
more accurate than Tier 1 because, instead of assuming industry-wide practices, it accounts for
reducing agents, furnaces, and other process materials that affect emissions. No equation is
given by the IPCC guidelines for this method.

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Technical Support Document for the Zinc Production Sector: Proposed Rule for Mandatory Reporting of

Greenhouse Gases

IPCC's Tier 3 method relies either on actual facility specific measurements of emissions, or on
facility specific calculation of emission factors and collection of activity data, multiplied by plant
production. No equation is given by the IPCC guidelines for this method.

3.2 Australian National Government's Greenhouse and Energy Reporting Program

The Australian National Government's Greenhouse and Energy Reporting Program requires
reporting of CO2 emissions from zinc producing corporations if: they control facilities that emit
at least 25,000 MtCC^e, or produce or consume at least 100 terajoules of energy; or their
corporate group emits at least 125,000 MtCC^e, or it produces or consumes at least 500
terajoules of energy (Australian DCC 2007). The method used for estimating emissions is based
on the National Greenhouse Account (NGA) default method, which calculates emissions based
on the following equation:

Ei = XQc x ECc x EFC / 1000

Where:

Ei = emissions of CO2 from production of metal, metric tonne

Qc = the quantity of each carbon reductant used in production of metal, metric tonne

ECc = the energy content of reductant, gigajoule per metric tonne

EFC= the emission factor of fuel used, kilogram per gigajoule

Facilities may use the default emission factor presented in Table 2, but the higher-order method
would be to develop facility-specific emission factors from the carbon content of the reducing
agent. This higher order method is similar in protocol to IPCC's Tier 3 requirements.

Table 2. Australian National Greenhouse Account Default Emission Factors

Fuel Combusted

Energy Content
(gross) GJ/t

Full Fuel Cycle EF
Emission Factor
kg C02e/GJ

Coke Oven Coke

27.0

125.7

Source: Australia National Greenhouse and Energy Reporting System 2007

(http://www.areenhouse.aov.au/reportina/publications/pubs/naer-techauidelines.pdfi

5

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Technical Support Document for the Zinc Production Sector: Proposed Rule for Mandatory Reporting of

Greenhouse Gases

3.3 Canadian Mandatory Greenhouse Gas Reporting Program

The Canadian Mandatory Greenhouse Gas Reporting Program requires reporting of CO2
emissions from zinc producing facilities if their total GHG emissions exceed 100,000 MtCC^e.
The method used for estimating emissions is based on the following equation:

EmissionSC02 = EFra X Mra + M C in Metal Ore X (44/12)

Where:

EFra= EF for the reducing agent, Mt C02/Mt reducing agent
Mra = mass of reducing agent consumed, Mt
M c in Metal Ore = mass of carbon in the metal ore feed, Mt
44/12 = stoichiometric ratio of CO2/C

The guidelines suggest the calculation and use of facility specific process-related emission
factors for the reducing agent consumed in order to ensure better accuracy of the estimates.
However, they also provide IPCC default emissions in the case that facility specific emission
factors can not be calculated. (Environment Canada 2006).

3.4 U.S. EPA's Inventory of U.S. Greenhouse Gas Emissions and Sinks

While these two protocols coalesce around the same methodology used for IPCC's Tier 3
protocol, the U.S. Inventory of Greenhouse Gas Emissions and Sinks utilizes IPCC's Tier 2
protocol with national default process specific emission factors, as discussed previously (US
EPA 2008).2

One difference to note between methodologies of the U.S. Inventory and the Australian Inventory is that the U.S.
Inventory does not consider the coke in secondary zinc production to be "combusted." Instead, the C02 emissions
from the coke are considered to be a process emission, not a stationary combustion emission. The U.S. Inventory
characterization of the coke consumption in secondary zinc production as a process emission is not consistent with
the terminology of "fuel combusted" in the Australia Inventory.

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Technical Support Document for the Zinc Production Sector: Proposed Rule for Mandatory Reporting of

Greenhouse Gases

4. Options for Reporting Threshold

4.1	Options Considered

Zinc smelters and secondary zinc recycling facilities in the U.S. vary in types and sizes of the
metallurgical processes used and mix of zinc-containing feedstocks processed to produce zinc
products. Options considered for reporting protocol include mandatory greenhouse gas reporting
from all zinc production facilities, capacity based emissions reporting, or emissions based
thresholds at 1,000, 10,000, 25,000, and 100,000 MTC02e.

4.2	Emissions and Facilities Covered Per Option
4.2.1 Process Emissions

In order to determine the process-related CO2 emissions for all zinc production facilities in the
U.S, EPA applied the IPCC Tier 2 method, which involves multiplying an emission factor based
upon the amount of EAF dust consumed by individual facilities' EAF dust consumption. Due to
the complexities of recovering zinc from recycled EAF dust, an emission factor based on the
amount of EAF dust consumed, rather than the amount of secondary zinc produced, was
developed to represent emissions from the Waelz Kiln process more accurately (U.S. EPA 2008).
This emission factor is calculated using the following equation:

EF eafDust = (0.4 Mt coke/Mt EAF Dust) x (0.84 Mt C/Mt coke) x (3.67 Mt C02/Mt C)
= 1.23 Mt C02/Mt EAF Dust

Specifically, to obtain CO2 emissions, the total 2006 secondary zinc production for the US was
multiplied by a fraction to get the portion of zinc attributed to the Horsehead Holding
Corporation's plant. This portion of secondary zinc was then multiplied by a Waelz Kiln process
emission factor for EAF dust to obtain total CO2 emissions. The default emission factor and
results of the analysis are presented below in Table 3.

Table 3. Facility Emission Calculations

Facility

Total
National
Secondary

Zinc
Production
(Mt)

Percent
Attributed
to Facility

Production
Attributed
to Facility
(Mt zinc)

EAF Dust
Consumption
Attributed to
Production

Emission
Factor
(Mt CO2I
Mt EAF
Dust)

co2

Attributed
to Facility
(Mt)

Horsehead Corporation

397,000

36%

142,929

425,384

1.23

528,777

7

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Technical Support Document for the Zinc Production Sector: Proposed Rule for Mandatory Reporting of

Greenhouse Gases

In total, 14 facilities were identified that have, or will have in the future, some form of zinc
production. Of these 14 facilities, five were not evaluated for process or combustion emissions,
and were not included in the cost analysis. Two of the five facilities are not listed in the
Directory of Metal Producers and therefore can be assumed to be producing Zinc Oxide, not zinc
metal (USGS Commodity Specialist).3 The other three facilities are planned to come on line in
the future.4

The remaining nine facilities were evaluated for process and combustion emissions. Of these
nine, three facilities have process emissions, and one facility uses a process that was assumed to
be emissive, totaling four process emissive facilities. These four facilities are part of Horsehead
Holding Corporation's production process, wherein six facilities each play a role in refining the
product and the final step is performed at the Monaca, PA plant.5 The Inventory of U.S.
Greenhouse Gas Emissions and Sinks: 1990 - 2006 provides the aggregated emission estimate
for Horsehead Holding Corporation. This estimate was split among the three plants that employ
processes which are known to contribute to the process emission estimate and the Monaca, PA
facility, which employs the electrothermic process. While the magnitude of emissions from the
electrothermic process is uncertain, this facility was included in this analysis due to its role as the
final processor of all of the Horsehead Holding Corporation's zinc (IPCC 2006). Due to the
nature of the production process that Horsehead Holding Corporation employs, the exact
contribution of each facility to the process emissions estimate has not been determined.
Secondary zinc products are processed and refined using several different processes at 5
facilities. These materials are then reprocessed at the Monaca, PA facility into final products.
Because materials are being recycled throughout this production process, dividing the estimate
from the Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2006 among the 4
facilities that employ process emissive production processes may underestimate the process
emissions resulting from Horsehead Holding Corporation's overall process. Table 4 includes
each of Horsehead Holding Corporation's facilities, the different products they produce, and
calculated zinc processing capacities. The process emissions from the Inventory of U.S.
Greenhouse Gas Emissions and Sinks: 1990-2006 was apportioned to the four facilities based on
the relative capacity of zinc produced.

3 The two facilities, US Zinc facilities in Millington, TN and Spokane, WA, are assumed to
produce zinc oxide are not included in this cost analysis because the analysis is focused on
emissions related to zinc metal production.

4 These three facilities include ZincOx's Big River Zinc and Ohio Projects (ZincOx Resources
Pic) and Steel Dust Recycling's Greenfield site in Pickens County, AL (Steel Dust Recycling,
LLC 2007).

5 While the Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 2006 says that the
Monaca, PA facility is shut down, our research shows that it is operational (Personal
Communication 2008, Horsehead Holding Corporation 2007).

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Technical Support Document for the Zinc Production Sector: Proposed Rule for Mandatory Reporting of

Greenhouse Gases

Table 4. Horsehead Holding Corporation Facilities Products and Calculated Zinc Production

Capacity

Facility Location

Product

Annual Capacity
(Metric Tons)

Zinc Production
Capacity
(Metric Tons)

Palmerton, PA

Calcine

117,936

76,658

Crude Zinc Oxide

247,666

136,216

Zinc Powder

4,536- 12,700.8

Zinc Copper

Base

2,722

NAa

Monaca, PA

Prime Western Metal

84,370

Zinc Oxide

76,205

61,231

SSHG Metal6

13,608

Zinc Dust

5,352

Rockwood, TN

Crude Zinc Oxide

134,266

73,846

Calumet, IL

Crude Zinc Oxide

153,317

84,324

Beaumont, TX

Crude Zinc Oxide

25,402

13,971

Bartlesville, OK

Lead Carbonate

25,402

Note 1: "Facility location", "Product", and "Annual Capacity" information is taken from Horsehead Holding
Corporation's Form 10-K. Zinc production capacity is calculated. For Calcine and Crude Zinc Oxide,
percentages of zinc content were multiplied by given capacities to calculate capacities of metric tons of zinc
produced. Prime Western and Special Special High Grade Metal were assumed to be 100% zinc. Zinc
powder and zinc dust were assumed to have 100% zinc content. Zinc powder is manufactured by the
atomization of molten zinc. The only distinction drawn between zinc dust and zinc powder is that zinc powder
is coarser than zinc dust (Horsehead Holding Corporation 2007).

Note 2: Totaling zinc production capacity for each plant to arrive at a total zinc production capacity for all
Horsehead facilities is potentially misleading as the same zinc may be processed at several different plants
before being sold.

Note 3: In this table, "Annual Capacity" is the amount of each zinc product, as listed in the "Product" column, that
each facility is potentially able to produce. "Zinc Production Capacity" is the amount of zinc content potentially
able to be produced. These numbers were reached through the calculations described in Note 1 above.

A Information on zinc content could not be found to estimate production capacity.

B SSHG Metal stands for Special Special High Grade Metal

The remaining five facilities included in the analysis used processes either confirmed or assumed
not to be process emissive. Horsehead Holding Corporation's Bartlesville, OK facility is not
process emissive (Sjardin 2003), and Nyrstar NV's Clarksville, TN, Votorantim Metals'
Coldwater, MI, and Houston, TX facilities, and Horsehead Holding Corporation's Beaumont, TX
facility were assumed to not be process emissive. These facilities were assumed not to be
process emissive due to a lack of information regarding the specific nature of the processes
employed at each facility.

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Technical Support Document for the Zinc Production Sector: Proposed Rule for Mandatory Reporting of

Greenhouse Gases

4.2.2 Combustion Emissions

Stationary combustion-related GHG emissions from on site fossil fuel combustion were
estimated for zinc production for nine facilities based on data collected on operations at the
Horsehead Holding Corporation's facility in Palmerton, PA and Nyrstar NV's Clarksville, TN
facility. The Horsehead Holding Corporation's facility operates four rotary kilns and a calcining
kiln (JTToday 2006). Operational data for the rotary kilns and calcining kiln were not available.
The rotary kilns were assumed to operate at 24 MMBtu/hour and calcining kiln at
50MMBtu/hour and were assumed to consume natural gas based on permit data collected for
secondary lead production rotary kilns (Indiana DOEM 2007) and silicon carbide production
calcining kilns (Illinois EPA 2004). These devices were assumed to run 24 hours/day, 365
days/year at 90% of capacity, totaling 1,151,064 MMBtu/year and GHG emissions of 61,135 Mt
of CC>2e. Because the Horsehead Holding Corporation facilities differ in size and capacity, this
estimate was scaled to approximate the size of each of the six Horsehead facilities and applied as
a proxy for plant specific data. Due to limited availability of information regarding the
Votorantim Metals facilities' equipment, the estimate for Horsehead's Palmerton, PA facility
was also scaled and applied to these two facilities. The Nyrstar NV Clarksville, TN facility
operates an auxiliary boiler, a roaster preheater, a primary acid plant preheater, and a secondary
acid plant preheater (TN Department of Environment and Conservation, 2002). Information on
energy consumption of this equipment was retrieved from Title V documentation (Tennessee
Department of Environment and Conservation 2002). Operational data for this equipment were
not available. These devices were assumed to run 24 hours/day, 365 days/year at 90% of
capacity, totaling 1,222,020 MMBtu/year and GHG emissions of 89,712 Mt of C02e. This
estimate was applied only to the Nyrstar NV facility.6

Emissions were estimated by multiplying the energy consumption (MMBtu/year) by the carbon
content of natural gas (14.47 Tg C/QBtu) provided by the Inventory of U.S. Greenhouse Gas
Emissions and Sinks 1990-2006 as well as CH4 and N2O emission factors provided by Table 2.3
of the 2006IPCC Guidelines for National Greenhouse Gas Inventories (IPCC 2006). These
factors are for Manufacturing Industries and Construction.

6 During research it was noted that the Horsehead Holding Corporation's Monaca, PA facility
operates a 110 megawatt coal-fired power plant that provides them with electricity. They sell
approximately one-fifth of this plant's electricity production capacity. This plant was not
included in these combustion emissions calculations.

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Technical Support Document for the Zinc Production Sector: Proposed Rule for Mandatory Reporting of

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4.2.3 Emissions Thresholds

Table 4 presents the estimated emissions and number of facilities that would be subject to GHG
emissions reporting, based upon emission estimates using production capacity data for a total of
nine U.S. zinc production facilities. As presented in Table 5, four of the nine facilities exceed a
threshold of 100,000 metric tons/year, and five of the nine facilities exceed a threshold of 25,000
metric tons/year. Eight of the nine exceed the threshold of 10,000 metric tons/year. All 9
facilities exceed a threshold of 1,000 metric tons/year.

Table 5. Threshold Analysis for Zinc Production

Threshold

Level
(MtC02e/yr)

Nationwide Annual GHG Emissions
(MtC02e/yr)

Total
Number

of
Entities

Subject to GHG Reporting

Process
Emissions

Combustion
Emissions

Total

Emissions

Entities

MtC02e/yr

Percent

Number

Percent

100,000

528,777

322,931

851,708

9

712,181

84%

4

44%

25,000

528,777

322,931

851,708

9

801,893

94%

5

56%

10,000

528,777

322,931

851,708

9

843,154

99%

8

89%

1,000

528,777

322,931

851,708

9

851,708

100%

9

100%

11

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Technical Support Document for the Zinc Production Sector: Proposed Rule for Mandatory Reporting of

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5. Options for Monitoring Methods

5.1 Option 1: Simplified Emission Calculation

The simplified emission calculation method uses a default process emission factor per unit of
output multiplied by national production activity data. This is a simplified emission calculation
method using only default emission factors to estimate CO2 emissions. The method requires
multiplying the amount of zinc produced by the appropriate default emission factors from the
2006 IPCC guidelines. This option is equivalent to IPCC's Tier 1 option.

5.2 Option 2: Facility-Specific Calculations

The method requires performing monthly measurements of the carbon content of specific process
inputs and measuring the mass rate of these inputs. This is the IPCC Tier 3 approach and the
higher order methods in the Canadian and Australian reporting programs. Implementation of this
method requires owners and operators of affected zinc smelters to determine the carbon contents
of materials added to the electrothermic furnace or Waelz kiln by analysis of representative
samples collected of the material or from information provided by the material suppliers. In
addition, the quantities of these materials consumed during production are measured and
recorded. To obtain the process-related CO2 emission estimate, the material carbon content
would be multiplied by the corresponding mass of material consumed and a conversion of carbon
to CO2. This method assumes that all of the carbon is converted during the reduction process.
Each facility owner or operator would be required to conduct quality assurance (QA) of supplier-
provided information on the carbon content of the input materials by collecting a composite
sample of material and sending it to a third-party, independent laboratory for chemical analysis
to verify the supplier's information. This QA procedure would be required to be conducted
annually.

The hybrid monitoring method requires facility specific measurements and reporting of process
and stationary combustion emissions consistent with the IPCC Tier 3 method of estimating zinc
emissions.

Implementation of this method requires facilities employing the electrothermic, Imperial
Smelting Furnace, or Waelz Kiln processes to perform on-site sampling of the amount of carbon
contained in the reducing agent, usually metallurgical coke, and to maintain records of the
masses of each reductant consumed. To obtain a process emission estimate, the carbon content
measurement would be multiplied by the mass of reductant consumed and a conversion of C to
CO2. This method assumes that all of the carbon is converted during the reduction process. If
several different types of reductants are used, each should be sampled and individual masses
consumed during production obtained to determine emissions from each type of reductant. No
equation is given by the IPCC guidelines for this method.

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5.3 Option 3: Direct Measurement (Annual Reporting)

For industrial source categories for which the process emissions and/or combustion GHG
emissions are contained within a stack or vent, direct measurement constitutes either
measurements of the 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 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.

5.3.1	Continuous Emissions Monitoring

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 the GHG (e.g., CO2) 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 GHGs in the stack gas and the flow rate of the stack gas.
The CEMS continuously withdraws and analyzes a sample of the stack gas and continuously
measures the GHG concentration and flow rate of the stack gas.

5.3.2	Stack testing

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.

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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., reducing agent carbon contents). Therefore, whenever a quality-assured value
of a required parameter is unavailable (e.g., if a monitor or CEMS malfunctions during unit
operation or if a required parameter is not obtained), a substitute data value for the missing
parameter must be used in the calculations.

6.1	Procedures for Option 1: Simplified Emission Calculation

If facility-specific production data is missing for one year, an average value using the production
data from the year prior and the year after the missing year may be calculated. Default emission
factors are readily available through IPCC guidelines (IPCC 2006).

6.2	Procedures for Option 2: Facility-Specific Calculations

When assuming a 100% conversion of C to CO2, no missing data procedures would apply
because this factor would be multiplied by the materials input, which are readily available. If
this amount of carbonaceous agent input is not available, a facility would need to extrapolate
from previous years taking into consideration any changes in production or process.

6.3	Procedures for Option 3: Direct Measurement
6.3.1 Continuous Emission Monitoring Data (CEMS)

For options involving direct measurement of CO2 flow rates or direct measurement of CO2
emissions using CEMS, Part 75 establishes procedures for management of missing data.
Procedures for management of missing data are described in Part 75.35(a), (b), and (d). In
general, missing data from operation of the CEMS may be replaced with substitute data to
determine the CO2 flow rates or CO2 emissions during the period in which CEMS data are
missing.

Under Part 75.35(a), the owner or operator of a unit with a CO2 continuous emission monitoring
system for determining CO2 mass emissions in accordance with Part 75.10 (or an O2 monitor that
is used to determine CO2 concentration in accordance with appendix F to this part) shall
substitute for missing CO2 pollutant concentration data using the procedures of paragraphs (b)
and (d) of this section. Subpart (b) covers operation of the system during the first 720 quality-
assured operation hours for the CEMS. Subpart (d) covers operation of the system after the first
720 quality-assured operating hours are completed.

Under Part 75.35(b), during the first 720 quality assured monitor operating hours following
initial certification at a particular unit or stack location (i.e., the date and time at which quality
assured data begins to be recorded by a CEMS at that location), or (when implementing these
procedures for a previously certified CO2 monitoring system) during the 720 quality assured
monitor operating hours preceding implementation of the standard missing data procedures in
paragraph (d) of this section, the owner or operator shall provide substitute CO2 pollutant
concentration data or substitute CO2 data for heat input determination, as applicable, according
to the procedures in Part 75.31(b). Note that for CEMS that are measuring process CO2

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emissions rather than combustion CO2 emissions, the term "heat input determination" may be
replaced with the term "raw material input determination."

Under Part 75.35(d), upon completion of 720 quality assured monitor operating hours using the
initial missing data procedures of Part 75.31(b), the owner or operator shall provide substitute
data for CO2 concentration or substitute CO2 data for heat input determination, as applicable, in
accordance with the procedures in Part 75.33(b) except that the term " CO2 concentration" shall
apply rather than "SO2 concentration," the term "CO2 pollutant concentration monitor" or "CO2
diluent monitor" shall apply rather than "SO2 pollutant concentration monitor," and the term
"maximum potential CO2 concentration, as defined in section 2.1.3.1 of appendix A to this part"
shall apply, rather than "maximum potential SO2 concentration."

6.3.2 Stack Testing Data

For options involving direct measurement of CO2 flow rates or direct measurement of CO2
emissions using stack testing, "missing data" is not generally anticipated. Stack testing
conducted for the purposes of compliance determination is subject to quality assurance
guidelines and data quality objectives established by the U.S. EPA, including the Clean Air Act
National Stack Testing Guidance published in 2005 (US EPA 2005). The 2005 EPA Guidance
Document indicates that stack tests should be conducted in accordance with a pre-approved site-
specific test plan to ensure that a complete and representative test is conducted. Results of stack
tests that do not meet pre-established quality assurance guidelines and data quality objectives
would generally not be acceptable for use in emissions reporting, and any such stack test would
need to be re-conducted to obtain acceptable data.

U.S. EPA regulations for performance testing under 40 CFR § 63.7(c)(2)(i) state that before
conducting a required performance test, the owner/operator is required to develop a site-specific
test plan and, if required, submit the test plan for approval. The test plan is required to include "a
test program summary, the test schedule, data quality objectives, and both an internal and
external quality assurance (QA) program" to be applied to the stack test. Data quality objectives
are defined under 40 CFR § 63.7(c)(2)(i) as "the pre-test expectations of precision, accuracy, and
completeness of data." Under 40 CFR § 63.7(c)(2)(ii), the internal QA program is required to
include, "at a minimum, the activities planned by routine operators and analysts to provide an
assessment of test data precision; an example of internal QA is the sampling and analysis of
replicate samples." Under 40 CFR § 63.7(c)(2)(iii) the external QA program is required to
include, "at a minimum, application of plans for a test method performance audit (PA) during the
performance test." In addition, according to the 2005 Guidance Document, a site-specific test
plan should generally include chain of custody documentation from sample collection through
laboratory analysis including transport, and should recognize special sample transport, handling,
and analysis instructions necessary for each set of field samples (US EPA 2005).

U.S. EPA anticipates that test plans for stack tests anticipated to be used to obtain data for the
purposes of emissions reporting would be made available to EPA prior to the stack test and that
the results of the stack test would be reviewed against the test plan prior to the data being
deemed acceptable for the purposes of emissions reporting.

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7. QA/QC Requirements

Facilities should conduct quality assurance and quality control of the production and
consumption data, supplier information (e.g., carbon contents), and emission estimates reported.
Facilities are encouraged to prepare an in-depth quality assurance and quality control plan which
would include checks on production data, the carbon content information received from the
supplier and from the lab analysis, and calculations performed to estimate GHG emissions.
Several examples of QA/QC procedures are listed below.

7.1 Combustion Emissions

Facilities should follow the guidelines described in the Stationary Combustion Source section of
this TSD.

7.2 Facilities Using CEMS for Direct Measurement of Process Emissions

For units using CEMS to measure CO2 flow rates or CO2 emissions, the equipment should be
tested for accuracy and calibrated as necessary by a certified third party vendor. These
procedures should be consistent in stringency and data reporting and documentation adequacy
with the QAQC procedures for CEMS described in Part 75 of the Acid Rain Program.

7.3 Equipment Maintenance

For methods using data obtained from flow meters to directly measure the flow rate of fuels, raw
materials, products, or process byproducts, flow meters should be calibrated on a scheduled basis
according to equipment manufacturer specifications and standards. Flow meter calibration is
generally conducted at least annually. A written record of procedures needed to maintain the
flow meters in proper operating condition and a schedule for those procedures should be part of
the QA/QC plan for the capture or production unit.

An equipment maintenance plan should be developed as part of the QA/QC plan. Elements of a
maintenance plan for equipment include the following: (1) conduct regular maintenance of
equipment, e.g. flow meters; (2) maintain a written record of procedures needed to maintain the
monitoring system in proper operating condition and a schedule for those procedures; and (3)
maintain a record of all testing, maintenance, or repair activities performed on any monitoring
system or component in a location and format suitable for inspection. A maintenance log may be
used for this purpose.

7.4 Data Management

Data management procedures should be included in the QA/QC Plan. Elements of the data
management procedures plan are as follows:

• For measurements of carbon content of reducing agents, assess representativeness of the
carbon content measurement of reducing agents and other process inputs by comparing
values received from supplier and/or laboratory analysis with IPCC default values.

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•	Check for temporal consistency in production data, process inputs, and emission estimate.
If outliers exist, they should be explained by changes in the facility's operations or other
factors. A monitoring error is probable if differences between annual data cannot be
explained by:

o Changes in activity levels,
o Changes concerning process inputs material,

o Changes concerning the emitting process (e.g. energy efficiency improvements)
(European Commission 2007).

•	Determine the "reasonableness" of the emission estimate by comparing it to previous
year's estimates and relative to national emission estimate for the industry:

o Comparison of data on fuel or input material consumed by specific sources with

fuel or input material purchasing data and data on stock changes,
o Comparison of fuel or input material consumption data with fuel or input material

purchasing data and data on stock changes,
o Comparison of emission factors that have been calculated or obtained from the fuel
or input material supplier, to national or international reference emission factors of
comparable fuels or input materials,
o Comparison of emission factors based on fuel analyses to national or international

reference emission factors of comparable fuels, or input materials,
o Comparison of measured and calculated emissions (European Commission 2007).

•	Maintain data documentation, including comprehensive documentation of data received
through personal communication:

o Check that changes in data or methodology are documented.

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8. Types of Emissions to be Reported

Zinc smelting owners and operators would report annual CO2 emissions. Owners and operators
would estimate annual CO2 emissions by estimating both process (CO2) and combustion related
greenhouse gas emissions (CO2, CH4, and N2O). Depending on the monitoring method used
(discussed in Section 6), additional information would be reported to assist in the verification of
the reported emissions. Such information could include facility operation information routinely
recorded at the facility such as the total number of operated at the facility, zinc product
production quantities, raw material quantities purchased and consumed, and fossil fuel usage. In
addition, facility owners and operators would report additional information to assist in QA/QC of
any site-specific GHG emissions data used for the reported emissions determination.

8.1 Additional Data to be Retained Onsite

Facilities should be required to retain data concerning monitoring of GHG emissions onsite for a
period of [at least five] years from the reporting year. For CEMS these data would include
CEMS monitoring system data including continuous-monitored GHG concentrations and stack
gas flow rates, calibration and quality assurance records. For stack testing these data would
include stack test reports and associated sampling and chemical analytical data for the stack test.
Process data including process raw material and product feed rates and carbon contents should
also be retained on site for a period of [at least five years] from the reporting year. EPA could
use such data to conduct trend analyses and potentially to develop process or activity-specific
emission factors for the process.

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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.

Environment Canada (2006). Facility Greenhouse Gas Emissions Reporting Program.
http://www.ee. gc.ca/pdb/ghg/guidance/protocols/2005_metal_mining/base_metals/s3_e.cfm#3.4.
3.2. Accessed 4/29/2008

IPCC (2006) 2006 IPCC 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.

European Parliament (2007). Official Journal of the European Union, August 31, 2007.
Commission Decision of 18 July 2007, "Establishing guidelines for the monitoring and reporting
of greenhouse gas emissions pursuant to Directive 2003/87/EC of the European Parliament and
of the Council. Available at http://eur-

lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2007:229:0001:0085:EN:PDF.

Horsehead Holding Corporation 2007. Form 10-K. Accessed at:
http://www.secinfo.com/dsVS7.t2Cg.htm

Illinois EPA (2004). Final "Revised" Title V - Clean Air Act Permit Program (CAAPP) Permit
and Title I Permit.. State of Illinois Environmental Protection Agency, Springfield, Illinois.

Indiana DOEM (2007) Administrative Amendment to Part 70 Operating Permit TO97-6201-
00079. Indiana Department of Environmental Management. Indianapolis, Indiana.

Personal communication (2008). Personal communication between ICF International's Charles
Cebul and a Horsehead Holding Corporation employee.

Porter, Frank C. 1991. The Zinc Handbook: Properties, Processing, and Use in Design.
International Lead Zinc Research Organization.

Reuters 2008. Horsehead Starts Up New Tennessee Kiln On Schedule. Accessed at:
http://www.reuters.com/article/pressRelease/idUS 128139+02-Jan-2008+PRN20080102

Steel Dust Recycling, LLC 2007. Application for Synthetic Minor Operating Permits. Accessed
at: http://www.adem.state.al.us/PublicNotice/June/SteelM.pdf

Sjardin, M. (2003) CO2 Emission Factors for Non-Energy Use in the Non-Ferrous Metal,
Ferroalloys and Inorganics Industry. Copernicus Institute. Utrecht, the Netherlands.

Tennessee Department of Environment and Conservation, 2002. Draft Operating Permit (Title
V) Number 546306. Obtained through personal communication on 7/15/08 between Erin Gray
of ICF International and Greg Forte of the State of Tennessee.

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Tolcin (2008). Personal communication between ICF International's Charles Cebul and USGS
Commodity Specialist Amy Tolcin. 7/16/2008.

US EPA (2003). Part 75, Appendix Bl, Available at
http ://www. epa. gov/ airmarkt/spm/rule/001000000B. htm.

U.S. EPA (2005). Clean Air Act National Stack Testing Guidance, U.S. Environmental
Protection Agency Office of Enforcement and Compliance Assurance, September 30, 2005,
www.epa.gov/compliance/resources/policies/monitoring/caa/stacktesting.pdf

U.S. EPA (2007). Climate Leaders, Inventory Guidance, Design Principles Guidance, Chapter 7
"Managing Inventory Quality". Available at

http://www.epa.gov/climateleaders/documents/resources/design_princ_ch7.pdf.

U.S. EPA (2008) Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2006. U.S.
Environmental Protection Agency, Washington D.C. USEPA #430-R-08-005.

USGS (2006) Minerals Yearbook: Zinc Annual Report. U.S. Geological Survey, Reston, VA.
Available at: http://minerals.usgs.gov/minerals/pubs/commoditv/zinc/mvbl-2006-zinc.pdf.

ZincOx Resources Pic. Company Website. Accessed at:
http://www.zincox.com/pages/recvcling/big_river.htm

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