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Home My WebLink AboutDAQ-2024-010077 US Magnesium / Ozone RACT Analysis Trinity Consultants OZONE REDSIGNATION TO SERIOUS NONATTAINMENT SIP RACT Analysis US Magnesium LLC Prepared By: TRINITY CONSULTANTS 4525 Wasatch Boulevard, Suite 200 Salt Lake City, UT 84124 801-272-3000 July 2024 Project 244502.0030 US Magnesium / Ozone RACT Analysis Trinity Consultants i TABLE OF CONTENTS 1. INTRODUCTION 1-1 2. PROCESS DESCRIPTION AND EMISSIONS CALCULATIONS 2-1 2.1 Description of Processes .......................................................................................... 2-1 2.1.1 Boron Process .......................................................................................................... 2-1 2.1.2 Magnesium Process .................................................................................................. 2-1 2.1.3 Lithium Carbonate Process ........................................................................................ 2-1 2.2 Emissions Profile ..................................................................................................... 2-1 3. RACT ANALYSIS BACKGROUND 3-1 3.1 RACT Methodology................................................................................................... 3-1 3.1.1 Step 1 – Identify All Reasonably Available Control Technologies ................................... 3-2 3.1.2 Step 2 – Eliminate Technically Infeasible Options ........................................................ 3-2 3.1.3 Step 3 – Rank Remaining Control Technologies by Control Effectiveness ....................... 3-2 3.1.4 Step 4 – Evaluate Most Effective Controls and Document Results ................................. 3-3 3.1.5 Step 5 – Select RACT ................................................................................................ 3-3 4. GAS TURBINES, DUCT BURNERS, AND SPRAY DRYERS 4-1 4.1 Turbine and Duct Burners NOX Technologies ............................................................ 4-2 4.1.1 Turbine and Duct Burner – Step 1 ............................................................................. 4-2 4.1.2 Turbine and Duct Burner – Step 2 ............................................................................. 4-4 4.1.3 Turbine and Duct Burner – Steps 3 -5 ........................................................................ 4-5 5. CHLORINE REDUCTION BURNER 5-1 5.1 Chlorine Reduction Burner Technologies .................................................................. 5-1 5.1.1 Chlorine Reduction Burner – Step 1 ........................................................................... 5-1 5.1.2 Chlorine Reduction Burner – Step 2 ........................................................................... 5-2 5.1.3 Chlorine Reduction Burner – Steps 3 through 5 ........................................................... 5-3 6. DIRECT FIRED BURNERS LESS THAN 5 MMBTU/HR 6-1 6.1 Description of Units ................................................................................................. 6-1 6.1.1 Cast House Furnaces ................................................................................................ 6-1 6.1.2 Preheating Equipment .............................................................................................. 6-1 6.1.3 Anode Oven ............................................................................................................. 6-1 6.2 Direct Fired Burners Less than 5 MMBtu/hr Analysis ................................................ 6-1 6.2.1 Direct Fired Burners – Step 1 .................................................................................... 6-1 6.2.2 Direct Fired Burners – Step 2 .................................................................................... 6-2 6.2.3 Direct Fired Burners – Steps 3 through 5 .................................................................... 6-2 7. SOLAR POND ENGINES 7-1 7.1 Diesel-Fired Prime Power Engines ........................................................................... 7-1 7.1.1 Solar Pond Engines – Step 1 ..................................................................................... 7-1 7.1.2 Solar Pond Engines – Step 2 ..................................................................................... 7-2 7.1.3 Solar Pond Engines – Step 3 ..................................................................................... 7-3 7.1.4 Solar Pond Engines – Step 4 ..................................................................................... 7-3 7.1.5 Solar Pond Engines – Step 5 ..................................................................................... 7-4 US Magnesium / Ozone RACT Analysis Trinity Consultants ii 8. FIRE PUMP ENGINE 8-1 8.1.1 Fire Pump Engines – Step 1 ...................................................................................... 8-1 8.1.2 Fire Pump Engines – Step 2 ...................................................................................... 8-1 8.1.3 Fire Pump Engines – Step 3 ...................................................................................... 8-2 8.1.4 Fire Pump Engines – Step 4 ...................................................................................... 8-3 8.1.5 Fire Pump Engines – Step 5 ...................................................................................... 8-3 9. BOILERS 9-1 9.1 Boiler NOX Technologies .......................................................................................... 9-1 9.1.1 Boilers – Step 1 ........................................................................................................ 9-1 9.1.2 Boilers – Step 2 ........................................................................................................ 9-3 9.1.3 Boilers – Step 3 ........................................................................................................ 9-4 9.1.4 Boilers – Step 4 ........................................................................................................ 9-4 9.1.5 Boilers – Step 5 ........................................................................................................ 9-5 10. LITHIUM PLANT SPRAY DRYERS 10-1 10.1 Spray Dryer NOX Technologies ............................................................................... 10-1 10.1.1 Lithium Spray Dryers – Step 1 ................................................................................. 10-1 10.1.2 Lithium Spray Dryers – Step 2 ................................................................................. 10-2 10.1.3 Lithium Spray Dryers – Steps 3 through 5 ................................................................ 10-4 APPENDIX A. COST ANALYSIS A-1 US Magnesium / Ozone RACT Analysis Trinity Consultants 1-1 1. INTRODUCTION US Magnesium LLC (USM) has been requested by the Utah Division of Air Quality (UDAQ) to submit a Reasonably Available Control Technology (RACT) analysis for oxides of nitrogen (NO X) emissions for its North Skull Valley site. This request is in response to the proposal UDAQ submitted to the U.S. Environmental Protection Agency (EPA) to revise its nonattainment boundary for the Northern Wasatch Front (NWF) 8-hour Ozone Nonattainment Area. UDAQ expects that EPA will act on this request upon redesignation from marginal to serious nonattainment in 2025. The proposed boundary would include USM in the NWF Serious Nonattainment Area starting in 2025. The Ozone Implementation Rule requires that the State Implementation Plan (SIP) associated with this redesignation include RACT measures for all major sources.1 USM has the potential to emit more than 70 tons or more per year of NOX, an ozone precursor, thus USM is considered a major source.2 USM is located at 12819 North Rowley Road, North Skull Valley, Utah. The scope of the NOX RACT analysis was defined with several emails and information exchanges between USM, UDAQ, and Trinity Consultants (Trinity). The resulting scope is as follows: ► A list of each of the NOX emission units at the facility; ► A physical description of each emission unit, including its operating characteristics; ► The proposed NOX RACT requirement or emission limitation (as applicable); and ► Supporting documentation for the technical and economic consideration for each affected emission unit. Based on a review of the issued Approval Order (AN107160050-20), recent informational submittals to UDAQ, and annual actual emissions reporting the following sources were identified for this NOX for RACT analysis: ► Turbines with duct burners; ► Chlorine Reduction Burner; ► Cast House Furnaces/Preheating Equipment/Anode Oven; ► Solar Pond Engines; ► Fire Pump Engine; ► Boilers; and ► Lithium Plant Spray Dryers. In some cases, equipment has been grouped for the purposes of the RACT analysis. All correspondence regarding this submission should be addressed to: Mr. Jeffrey Mensinger Environmental Manager 12819 N Rowley Road North Skull Valley, UT 84029 Email: jmensinger@usmagnesium.com 1 Implementation of the 2015 National Ambient Air Quality Standards for Ozone: Nonattainment Area State Implementation Plan Requirements, 83 Fed. Reg. 62,998 (Dec. 6, 2018) 2 The major source threshold was lowered to 70 tpy with the implementation of the PM2.5 Serious Nonattainment SIP US Magnesium / Ozone RACT Analysis Trinity Consultants 2-1 2. PROCESS DESCRIPTION AND EMISSIONS CALCULATIONS 2.1 Description of Processes 2.1.1 Boron Process The Boron Plant utilizes concentrated Great Salt Lake (GSL) brine to extract boron prior to further processing in the magnesium production process. The brine passes through a solvent extraction step where a long chain alcohol in a kerosene carrier is used to remove the naturally occurring boron from the solution. No NOX emissions are anticipated. 2.1.2 Magnesium Process USM extracts magnesium metal from the waters of the Great Salt Lake. Some of the water is evaporated in a system of solar evaporation ponds and the resulting brine solution is purified and dried to a powder in spray dryers. The powder is then melted and further purified in the melt reactor before going through an electrolytic process to separate magnesium metal from chlorine. The metal is then refined and/or alloyed and cast into molds. The chlorine from the melt reactor is combusted with natural gas in the chlorine reduction burner (CRB) and converted into hydrochloric acid (HCl). The HCl is removed from the gas stream through a scrubber train. The chlorine that is generated at the electrolytic cells is collected and piped to the chlorine plant where it is liquefied for reuse or sale. 2.1.3 Lithium Carbonate Process USM has also permitted a new processing plant to produce battery grade lithium carbonate. The process will dissolve cell salt (derived from the primary magnesium production process) in an aqueous (water) solution with hydrochloric acid added to convert hydroxide salts to chloride salts. The process then recovers the lithium by removal of the divalent cations, magnesium and calcium, through precipitation and selective ion exchange. The process steps convert the lithium salts (primarily lithium chloride) into lithium carbonate. During the final process steps, the lithium carbonate liquor is filtered and then the filter cake is dried, milled into the final form, and packaged for sale as dry, lithium carbonate powder. 2.2 Emissions Profile Through recent permitting actions, USM has established the following potential to emit (PTE) profile for NOX. A full explanation of calculation methods and inputs can be found within the permitting files. Table 2-1. Facility-wide Potential to Emit NOX PTE (tpy) 1,260.99 Facility-wide actual emissions for NOX as recorded within UDAQ’s State and Local Emission Inventory System (SLEIS) are included in Table 2-2. US Magnesium / Ozone RACT Analysis Trinity Consultants 2-2 Table 2-2. Facility-wide Actual Emissions Emission Unit ID Emission Unit NOX Emission Rate (tpy) Average NOX Emissions (tpy) Year 2017 2018 2019 2020 2021 2022 2023 3363 Turbine 01 + Duct Burner 01 305.99 284.42 262.86 248.06 184.68 86.75 --- 228.79 3364 Turbine 02 + Duct Burner 02 295.413 274.50 253.10 122.46 171.69 113.10 --- 205.04 3365 Turbine 03 + Duct Burner 03 274.27 254.66 233.57 245.68 243.39 81.27 --- 222.14 3331 Crucible furnace, 01 --- --- --- --- --- 4.74 --- 4.74 3685 Stack, Boiler Riley3 --- --- --- --- --- 4.00 --- 4.00 9166 Chlorine reduction burner --- --- --- --- --- 3.02 --- 3.02 178399 Compressor --- --- --- --- --- 0.15 0.11 0.13 178413 All Diesel Engines < 600 hp --- --- --- --- --- 38.31 26.60 32.45 181049 Production of HCl by controlled combustion of chlorine gas and natural gas --- --- --- --- --- 0.03 --- 0.03 181170 Heating, propane, South pump Station --- --- --- --- --- 0.02 0.01 0.02 181194 Casthouse tool preheating and other open air burning --- --- --- --- --- 0.31 --- 0.31 185893 1500 hp boiler lithium carbonate plant --- --- --- --- --- 0.13 1.32 0.73 Yearly Totals (tpy) 875.67 813.58 749.53 616.20 599.77 402.31 69.28 767.08 3 This unit is no longer operational. US Magnesium / Ozone RACT Analysis Trinity Consultants 3-1 3. RACT ANALYSIS BACKGROUND A RACT analysis has been conducted for each of the following sources: ► Turbines with duct burners; ► Chlorine Reduction Burner; ► Cast House Furnaces/Preheating Equipment/Anode Oven; ► Solar Pond Engines; ► Fire Pump Engines; ► Boilers; and ► Lithium Plant Spray Dryers. USM has organized the RACT analysis by emission unit group in this analysis in accordance with U.S. EPA’s “top-down” procedures per UDAQ guidance.4 3.1 RACT Methodology EPA has defined RACT as follows: The lowest emission limitation that a particular source is capable of meeting by the application of control technology that is reasonably available considering technological and economic feasibility.5 RACT for a particular source is determined on a case-by-case basis considering the technological and economic circumstances of the individual source.6 In EPA’s State Implementation Plans; General Preamble for Proposed Rulemaking on Approval of Plan Revisions for Nonattainment Areas – Supplement (on Control Techniques Guidelines), it provided a recommendation to states which says: …each [Control Technique Guideline] CTG contains recommendations to the States of what EPA calls the “presumptive norm” for RACT, based on EPA’s current evaluation of the capabilities and problems general to the industry. Where the States finds the presumptive norm applicable to an individual source or group of sources, EPA recommends that the State adopt requirements consistent with the presumptive norm level in or to include RACT limitations in the SIP.7 USM has referenced the published CTG’s as well as Utah Administrative Code (UAC) for Air Quality (R307), and proposed rules which establish a current presumptive norm specific to the NWF NAA. The preamble goes on to state: 4 UDAQ Ozone SIP Planning RACT Analysis, provided January 9, 2023 5 EPA articulated its definition of RACT in a memorandum from Roger Strelow, Assistant Administrator for Air and Waste Management, to Regional Administrators, Regions I-X, on Guidance for Determining Acceptability of SIP Regulations in Non- Attainment Areas,” Section 1.a (December 9,1976). 6 Federal Register/Vol. 44. No. 181/Monday, September 17,1979/Proposed Rules – State Implementation Plan; General Preamble for Proposed Rulemaking on Approval of Plan Revisions for Nonattainment Areas – Supplement (on Control Techniques Guidelines). 7 IBID. US Magnesium / Ozone RACT Analysis Trinity Consultants 3-2 …recommended controls are based on capabilities and problems which are general to the industry; they do not take into account the unique circumstances of each facility. In many cases appropriate controls would be more or less stringent. States are urged to judge the feasibility of imposing the recommended control on particular sources, and adjust the controls accordingly. Guidance provided by UDAQ for this RACT analysis states that this analysis is to be conducted using the “top-down” method.8 In a memorandum dated December 1, 1987, the EPA detailed its preference for a “top-down” analysis which contains five (5) steps.9 If it can be shown that the most stringent level of control is technically, environmentally, or economically infeasible for the unit in question, then the next most stringent level of control is determined and similarly evaluated. This process continues u ntil the RACT level under consideration cannot be eliminated by any substantial or unique technical, environmental, or economic objections. Presented below are the five basic steps of a “top-down” RACT review as identified by the EPA. 3.1.1 Step 1 – Identify All Reasonably Available Control Technologies Available control technologies are identified for each emission unit in question. The following methods are used to identify potential technologies: 1) researching the RACT/BACT/LAER Clearinghouse (RBLC) database, 2) surveying regulatory agencies, 3) drawing from previous engineering experience, 4) surveying air pollution control equipment vendors, and/or 5) surveying available literature. Additionally, current CTG’s as well as UAC R307, and proposed rules were reviewed to establish a current presumptive norm specific to the NWF NAA. 3.1.2 Step 2 – Eliminate Technically Infeasible Options To ensure the presumptive norm established applies to the emission source in question a full review of available control technologies is conducted in the second step of the RACT analysis. In this step each technology is reviewed for technical feasibility and those that are clearly technically infeasible are eliminated. EPA states the following with regard to technical feasibility:10 A demonstration of technical infeasibility should be clearly documented and should show, based on physical, chemical, and engineering principles, that technical difficulties would preclude the successful use of the control option on the emissions unit under review. 3.1.3 Step 3 – Rank Remaining Control Technologies by Control Effectiveness Once technically infeasible options are removed from consideration, the remaining options are ranked based on their control effectiveness. If there is only one remaining option or if all the remaining technologies could achieve equivalent control efficiencies, ranking based on control efficiency is not required. 8 UDAQ Ozone SIP Planning RACT Analysis, provided January 9, 2023 . 9 U.S. EPA, Office of Air and Radiation. Memorandum from J.C. Potter to the Regional Administrators. Washington, D.C. December 1, 1987. 10 U.S. EPA, New Source Review Workshop Manual (Draft): Prevention of Significant Deterioration and Nonattainment Area Permitting, October 1990. US Magnesium / Ozone RACT Analysis Trinity Consultants 3-3 3.1.4 Step 4 – Evaluate Most Effective Controls and Document Results Beginning with the most effective control option in the ranking, detailed economic, energy, and environmental impact evaluations are performed. If a control option is determined to be economically feasible without adverse energy or environmental impacts, it is not necessary to evaluate the remaining options with lower control effectiveness. The economic evaluation centers on the cost effectiveness of the control option. Costs of installing and operating control technologies are estimated and annualized following the methodologies outlined in the EPA’s OAQPS Control Cost Manual (CCM) and other industry resources.11 Note that the purpose of this analysis is not to determine whether controls are affordable for a particular company or industry, but whether the expenditure effectively allows the source to meet pre-established presumptive norms. 3.1.5 Step 5 – Select RACT In the final step the lowest emission limitation is proposed as RACT along with any necessary control technologies or measures needed to achieve the cited emission limit. This proposal is made based on the evaluations from the previous step. 11 Office of Air Quality Planning and Standards (OAQPS), EPA Air Pollution Control Cost Manual, Sixth Edition, EPA 452-02-001 (https://www.epa.gov/economic-and-cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution), Daniel C. Mussatti & William M. Vatavuk, January 2002. US Magnesium / Ozone RACT Analysis Trinity Consultants 4-1 4. GAS TURBINES, DUCT BURNERS, AND SPRAY DRYERS USM has permitted the operation of three (3) 12,700 kW natural gas turbines, three (3) 15.3 MMBtu/hr duct burners, and three (3) spray dryer units. This set of equipment is considered together for RACT as they are integrated to produce electricity, provide heat to the process stream, and limit energy waste. Specifically, the exhaust from each turbine is routed to a duct burner to increase the temperature before being routed to a spray dryer. The heated exhaust is used to dry the magnesium chloride (MgCl 2) slurry into a magnesium chloride powder. For the spray dryer to work properly, the inlet air temperature needs to reach 1,000 F. The exhaust temperature from the turbines is 900 F, and the duct burners boost the temperature to 1,000 F. This process is further explained in the figure below. Figure 4-1 – Turbine, Duct Burner, and Spray Dryer Process Due to the integrated nature of this process all units have been considered under a single RACT. This approach is consistent with the reporting conducted by USM over the past six (6) years as demonstrated in the table below: Table 4-1. Actual NOX Emissions for the Turbines and Duct Burners as Reported in SLEIS Year Train 1 (tpy) Train 2 (tpy) Train 3 (tpy) Total (tpy) 2023 Not Operated Not Operated Not Operated Not Operated 2022 86.75 113.10 81.27 281.12 2021 184.68 171.69 243.39 599.77 2020 248.06 122.46 245.68 616.20 2019 262.86 253.10 233.57 749.53 2018 284.42 274.50 254.66 813.58 2017 305.99 295.41 274.27 875.67 As indicated in the table above, the turbines and duct burners are not currently operating due to the need for extensive repair. US Magnesium / Ozone RACT Analysis Trinity Consultants 4-2 USM understands that in some cases control technologies may be specific to either a turbine or duct burners. Where appropriate, turbine- and duct burner-specific control technologies have been identified as such. The following review will detail controls as they apply to normal operations. Startup and shutdown operations manage emission rates by minimizing the duration of startup and shutdown. During a startup event, USM will bring the turbine to the minimum load necessary to achieve compliance with the applicable NOX emission limits as quickly as possible, consistent with the equipment manufacturers’ recommendations and safe operating practices. During a shutdown, USM will reduce the turbine load to zero as quickly as possible, consistent with the equipment manufacturers’ recommendations and safe operating practices. 4.1 Turbine and Duct Burners NOX Technologies Two major sources of NOX are formed during combustion by two separate mechanisms: thermal NOX and fuel NOX. Since natural gas is relatively free of fuel-bound nitrogen, the contribution to the formation of fuel NOX emissions in natural gas-fired equipment is minimal and thermal NOX is the major component of NOX emissions. Thermal NOX formation is a function of residence time, oxygen level, and flame temperature, and can be minimized by controlling these elements in the design of the combustion equipment. The turbines were installed prior to February 18, 2005, and thus predate New Source Performance Standards (NSPS) given for stationary combustion turbines (Subpart KKKK). However, this subpart along with currently issued BACT/RACT determinations and the RBLC have been reviewed to identify potential control technologies. The current design of the turbine and duct burner is estimated to emit NO x at a rate of 326.4 lb/MMscf or 76.28 lb/hr. 4.1.1 Turbine and Duct Burner – Step 1 Potential control technologies were identified through the review of the following: ► California Air Resources Board (CARB) BACT Guidelines Tool ► EPA’s RBLC Database for Combined Cycle Turbines (16.210);12 ► EPA Alternative Control Techniques Document – NOX Emissions from Stationary Gas Turbines; and ► NSPS KKKK – Standards of Performance for Stationary Combustion Turbines. The following technologies were identified: 12 Database accessed May 14, 2024. US Magnesium / Ozone RACT Analysis Trinity Consultants 4-3 Table 44-2. NOX Turbine Controls and Emission Rates from RBLC13 Source Emission Rate Process Control Method Notes RBLC - Agrium U.S. INC. 5 PPMV @ 15% O2 Five (5) Natural Gas-Fired Combustion Turbines Selective Catalytic Reduction and SoLoNOx Technology on Turbines Conducted 05//24024 and filtered to only display NOX emission rates for units with process code 16.21, and burning natural gas. RBLC - Midwest Fertilizer Corporation 22.65 PPMVD @ 15% oxygen Two (2) Natural Gas-Fired Combustion Turbines Dry Low NOX combustors Conducted 05//24024 and filtered to only display NOX emission rates for units with process code 16.21, and burning natural gas. RBLC - Equistar Chemicals, LP 80 ppm @ 3% O2 Dry Solar Titan 130 Gas Turbine with Unfired HRSG Dry Low NOx combustors(SoLoNOx) Good combustion practices: good equipment design, use of gaseous fuels for good mixing, proper combustion techniques. Conducted 05//24024 and filtered to only display NOX emission rates for units with process code 16.21, and burning natural gas. RBLC - Sabine Pass LNG, LP and Sabine Pass Liquefaction 150 PPM @ 15% O2 and <75% load Generator Turbines Dry Low NOX Good combustion practices Conducted 05//24024 and filtered to only display NOX emission rates for units with process code 16.21, and burning natural gas. RBLC - Matep Limited Partnership 2 PPMVD @ 15% O2 Combustion Turbine with Duct Burner Dry Low NOX Combustor Selective catalytic reduction Conducted 05//24024 and filtered to only display NOX emission rates for units with process code 16.21, and burning natural gas. RBLC - Massachusetts Institute of Technology 2 PPMVD @ 15% O2 Combustion Turbine with Duct Burner Dry Low NOX Combustor for CTG Selective catalytic reduction Conducted 05//24024 and filtered to only display NOX emission rates for units with process code 16.21, and burning natural gas. RBLC - M & G Resins USA LLC 2 PPMVD Cogeneration Turbine Selective catalytic reduction Conducted 05//24024 and filtered to only display NOX emission rates for units with process code 16.21, and burning natural gas. The technologies identified as possible NOX reduction technologies for small combustion, combined cycle and cogeneration turbines are shown in the table below. US Magnesium / Ozone RACT Analysis Trinity Consultants 4-4 Pollutant Control Technologies NOX Dry Low NOX Combustors/Low NOX Burner (Turbine) Low NOx/Ultra-low NOx burners (Duct Burner) Selective Catalytic Reduction (SCR) Water/Steam Injection Natural Gas Usage and Good Combustion Practices Control technologies included in this table are those that have been shown in practice for use in one of the previously listed databases. 4.1.2 Turbine and Duct Burner – Step 2 Dry Low NOX Combustors/Low NOX Burner (Turbine Only) Although dry low NOX (DLN) combustors designed by different manufacturers may vary in design, they all employ the strategies of fuel and air pre-mixing and staged combustion to minimize NOX formation in combustion turbines. The combustors burn a lean, pre-mixed fuel and air mixture to avoid localized high temperature regions. A lean air-to-fuel ratio approaching the lean flammability limit is maintained, and the excess air acts as a heat sink to lower combustion temperatures, which lowers thermal NOX formation. A pilot flame is used to maintain combustion stability in this fuel-lean environment. Other techniques, such as variable geometry, fuel staging, or combustion staging, are also incorporated in DLN combustor design. The RBLC reports the following emission rates for low NO X combustion designs: ► 20 lb/MMscf ► 15 to 150 ppm ► 14.25 lb/hr14 In comparison to currently estimated emission rates, this represents an emission reduction potential of approximately 88%. The replacement of existing turbines with those that utilize DLN is considered technically feasible. Low NOx/Ultra-Low NOX Burner (Duct Burner Only) LNB/ULNB technology uses advanced burner design to reduce NO X formation through the restriction of oxygen, flame temperature, and/or residence time. This involves carefully controlling the air to fuel ratio and potentially directing the hot O2 depleted flue gas from the heater into the combustion zone. Any change in the turbine burner will affect the exhaust parameters, such as temperature and turbulence, thus affecting the downstream duct burner, and likely requiring its replacement. The most comparable sources within the RBLC and available permits indicate emission rates consistent LNB/ULNB technology. As a result, the replacement of the duct burner is not considered independently from the installation of a DLN system. As with the replacement of the turbine burner, the replacement of these units with those that utilize an LNB/ULNB is considered technically feasible. 14 Note that the emission rates presented were reported for a variety of units and thus represent the potential rage of emission rates possible with this control technology. Reviewed sources include the RBLC and comparable sources. US Magnesium / Ozone RACT Analysis Trinity Consultants 4-5 Selective Catalytic Reduction SCR refers to the process in which NOx is reduced by ammonia over a heterogeneous catalyst in the presence of oxygen. SCR can be applied as a stand-alone NOX control or with other technologies such as combustion controls. The SCR process requires a reactor, a catalyst, and an ammonia storage and injection system. The effectiveness of an SCR system is dependent on a variety of factors, including the inlet NO x concentration, the exhaust temperature, the ammonia injection rate, and the type of catalyst . The turbines/duct burners at USM are not only used to produce electricity, but also to dry the magnesium chloride product. Ammonia injected into the exhaust stream will come into contact with powdered magnesium chloride product, the temperatures and residence time of the process allow fo r the formation of ammonium salts which contaminate the product. USM proposes that the potential for product contamination renders SCR technically infeasible. USM also considered an SCR system at the outlet of the spray dryer. However, a secondary burner would be required to bring the exhaust from the current temperature of 155 °F to the minimum SCR operating temperature of 480 °F. The requirement for an additional burner, and natural gas to support it, reduces the potential for emissions reduction to a minimal reduction. Thus, USM considers SCR to be technically infeasible. Water/Steam Injection Combustion control using water or steam lowers combustion temperatures, which reduces thermal NO X formation. Water or steam, treated to quality levels comparable to boiler feedwater, is injected into the combustor and acts as a heat sink to lower flame temperatures. This control technique is available for all new turbine models and can be retrofitted to most existing installations. Although uncontrolled emission levels vary widely, the range of achievable controlled emission levels using water or steam inje ction is relatively small. Controlled NOX emission levels range from 25 to 42 ppmv for natural gas fuel.15 Injection of water or steam naturally increases the humidity of the exhaust stream. Since the exhaust is further utilized to dry the magnesium chloride product, increasing the humidity requires the use of higher temperatures and/or flow rates. Increasing either of these parameters will require a higher natural gas flow rate to the turbine and duct burner, thereby increasing emissions. USM proposes that the use of water/ steam would greatly reduce the energy recovery of the process and thus is technically infeasible. Good Combustion Practices Good combustion practices involve controlling the operating parameters of the combustors for temperature and turbulence, excess oxygen levels, and air/fuel mixing to ensure continual operation as close to optimum (i.e., minimum emission) conditions as possible. This is considered technically feasible. 4.1.3 Turbine and Duct Burner – Steps 3 -5 The only technically feasible control technologies are DLN for turbines, LNB/ULNB for the duct burners, and general good combustion practices. Upon coordination with a turbine vendor and conducting a preliminary cost analysis, USM found that the cost per ton removed was less than established UDAQ thresholds for large businesses. As a result, the replacement of the turbine and duct burners is proposed as RACT. At the time of replacement USM will work with vendors to establish appropriate emission rates. 15 Alternative Control Techniques Document— NOX Emissions from Stationary Gas Turbines US Magnesium / Ozone RACT Analysis Trinity Consultants 4-6 As noted in section 4.1, the turbines and duct burners are not currently operational. Thus, USM proposes that the compliance timeline for this change is to be prior to the start-up of operation. US Magnesium / Ozone RACT Analysis Trinity Consultants 5-1 5. CHLORINE REDUCTION BURNER Brine powder, consisting of salts evaporated from the Great Salt Lake, is melted in a melt reactor with chlorine added to convert any MgO to MgCl2, which results in chlorine gas as a byproduct. To abate this chlorine gas, the chlorine reduction burner (CRB) is used in series with a wet scrubber(quench system). The CRB uses only natural gas as fuel, which is oxidized by chlorine and oxygen (from air), resulting in carbon dioxide and hydrogen chloride gas. The reaction is as follows: CH4 + O2 + 2Cl2 → CO2 + 4HCl A wet scrubber is then used to entrain the hydrogen chloride gas into the liquid phase for further treatment or use in other USM production processes. The CRB is used to control the majority of chlorine emissions from the facility. For an efficient chemical conversion of Cl2 to HCl, the CRB must operate between the temperatures of 1 ,650 °F and 2,000 °F .16 This is the optimum temperature range to achieve the required DRE, or conversion of chlorine gas within the burner combustion zone. Air to fuel ratios within the burner must also be controlled within a certain range to maintain the appropriate chemical conversion of chlorine to hydrogen chloride. 5.1 Chlorine Reduction Burner Technologies USM is currently the only producer of primary magnesium in North America and has been in operation since 1972. Given the age of the facility and it’s unique connection to the Great Salt Lake , the North Skull facility is the only facility that operates this unique chlorine reduction burner (CRB). design This unit was custom designed for USM 1989. Chlorine is gas generated at the USM site from both the melt reactor process and from the chlorine (purification) plant and is reacted within the CRB in the presence of heat, oxygen and methane, producing CO2 gas and hydrogen chloride gas (HCl). The HCl then passes through a quench system that cools the HCl using water and heat exchangers. The HCl is scrubbed in an absorber to be recovered as hydrochloric acid liquid before the exhaust stream is further scrubbed in several packed bed scrubbers, and then vented to the atmosphere. Some of the hot chlorine gas, which is collected from various plant processes, is sent to the chlorine plant where it is cleaned, dried and liquefied. The liquid chlorine is sold or used in the Melt Reactor process. Tail gas from the chlorine plant which contains air and a small amount of chlorine that cannot be liquefied is sent to the CRB where it is ultimately recovered in the acid scrubber train. Any change in chemistry, air-to-fuel ratio, or set up must be carefully evaluated so as not to affect the abatement efficiency of the CRB or other factory processes. 5.1.1 Chlorine Reduction Burner – Step 1 The NOX formed during combustion in the CRB is from two major mechanisms: thermal NO X and fuel NOX. Since natural gas is relatively free of fuel-bound nitrogen, the contribution of this second mechanism to the formation of NOX emissions in natural gas-fired equipment is minimal, leaving thermal NOX as the main 16 UDAQ Title V Operating Permit #4500030003 dated December 12, 2018 US Magnesium / Ozone RACT Analysis Trinity Consultants 5-2 source of NOX emissions. Thermal NOX formation is a function of residence time, oxygen level, and flame temperature, and can be minimized by controlling these elements in the design of the combustion equipment. The technologies evaluated were identified through a review of the RBLC, EPA’s “Nitrogen Oxides (NOX), Why and How They Are Controlled”, technical white papers, operational experience and engineering judgement. Because USM is the only of its kind in the United States, these searches focused identifying the most similar units based engineering and process related experience with other burners and furnaces. While they may be in use for newer equipment designs, they have never been proven with a CRB of this design. Possible NOX reduction technologies for the CRB are shown in the table below. Pollutant Control Technologies NOX Low NOX Burners (LNB) Ultra-Low NOX Burners (UNLB) Flue Gas Recirculation (FGR) Selective Catalytic Reduction (SCR) Good Combustion Practices (GCP) 5.1.2 Chlorine Reduction Burner – Step 2 Thermal NOX formation is a function of residence time, oxygen level, and flame temperature, and can be minimized by controlling these elements in the design of the combustion equipment. Residence time, oxygen level, and flame temperature also influence the Cl2 removal efficiency of the CRB, so any control technology must attain a delicate balance between reducing NO X and interfering with the chemical and thermal reaction which abates Cl2. Combustion Controls Combustion controls such as water or steam injection or temperature control are not feasible, because it would lower the temperature required to treat the chlorine gas. The CRB requires an operating temperature of no less than 1,650 °F and no more than 2,000 °F for proper operation and has strict monitoring requirements listed in their Title V operating permit. Combustion techniques that lower the formation of thermal NO X by lowering the peak flame temperature are not a viable option for control as they would impact the CRB’s main function of reducing the chlorine emissions that are emitted to the atmosphere. Therefore, NOX emission reduction retrofit controls are technically infeasible for the CRB. FGR and LNB/ULNB Burner Design FGR takes a portion of the flue gas from the combustion and recirculates it back through the burner, which dilutes the fuel-air mixture with inert gases and reduces the flame temperature. Low-NOX and Ultra-Lo w- NOX burners work by staged combustion, where air to fuel mixtures are varied in zones to slow the combustion process (increase residence time) and reduce peak flame temperature. As mentioned above, CRB temperatures cannot be modified since it would affect the chlorine gas abatement. Methane concentrations in the burner must be maintained in the correct balance for adequate US Magnesium / Ozone RACT Analysis Trinity Consultants 5-3 conversion of Cl2 to HCl. At lower methane concentrations, methane will be oxidized by oxygen in the air. At adequate methane concentrations, methane will be oxidized by chlorine, converting more Cl2 to HCl. Varying air to fuel mixtures in this process could therefore affect the abatement of chlorine and is considered technically infeasible in this process. Selective Catalytic Reduction (SCR) SCR uses a reagent such as ammonia, which is vaporized by heat before it is injected into the exhaust stream. In this exhaust stream, NOX reacts with the ammonia in the presence of a catalyst, yielding water, nitrogen, and carbon dioxide. The exhaust leaving the CRB contains HCl gas, which would quickly react with ammonia to form ammonium chloride salts. This chemical reaction creates submicron particles that follow the gas stream, poisoning the catalyst, potentially causing operational problems including solids buildup, and resulting in additional PM emissions from the facility.17 Ammonium salt solids can result in increased corrosion of ducting and equipment components, and reduced packed scrubber efficiency from salt fouling and consumption of any dosing chemical, which could violate the emission requirements found in 40 CFR 63 Subpart TTTTT. In addition, the hydrochloric acid captured in the subsequent water scrubber will be recirculated through the process to decrease waste and increase production. Injection of ammonia and the resulting ammonium chloride salts could contaminate that stream and lower product quality. Thus, SCR is considered technically infeasible for the CRB. . 5.1.3 Chlorine Reduction Burner – Steps 3 through 5 The CRB is a control device for chlorine emissions at USM which must maintain an operating temperature of 1,650 °F to 2,000 °F. As such combustion controls are not a viable option for controlling the formation of thermal NOX and would impact the design of the burner thereby altering its intended purpose. Post-combustion controls are similarly infeasible; the use of a catalyst to remove NO X could interfere with the scrubber’s operation and result in emissions that violate the emissions standards that are listed in the appliable MACT, Subpart TTTTT. As no control technologies are technically feasible for the specific operations at USM, no ranking and subsequent evaluation of effectiveness for removing NOX emissions is possible. USM proposes to continue to operate the CRB as it is currently configured. 17 P. V. Broadhurst, “Removal of Chloride Compounds,” Decarbonization Technology, April 2003. Accessed June 2024. US Magnesium / Ozone RACT Analysis Trinity Consultants 6-1 6. DIRECT FIRED BURNERS LESS THAN 5 MMBTU/HR 6.1 Description of Units USM operates a series of cast house furnaces, preheating equipment, as well as an anode oven which each contain a series of natural gas burners rated at less than 5 MMBtu/hr each. Historically many of these units have been combined for emission reporting, the total emissions for these units are based on a maximum fuel throughput of 293,946,000 cubic feet of natural gas. A description of each unit type is given below: 6.1.1 Cast House Furnaces USM has permitted eleven (11) cast house furnaces, #1 thru #11, each crucible furnace is equipped with six 1 MMBtu/hr burners, three in an upper horizontal angled array and three in a lower horizontal angled array, for a total heating rating of 6 MMBtu/hr per crucible furnace. The purpose of these furnaces is to process molten magnesium into its final product through pouring it into various molds. 6.1.2 Preheating Equipment The cast house also utilizes tool heating boxes, they are top and open -faced boxes with four small bayonet style burners, these burners typically range from 0.1 to 0.25 MMBtu/hr. The tool heating boxes sole purpose is safety. The tools used in the casting house are heated up to remove any potential for water vapor or condensation forming on the metal when it contacts the heated magnesium metal. Water and magnesium can result in the formation of hydrogen gas, which is very explosive. These tool heating boxes are an integral part of the process and their purpose if primarily for safety. 6.1.3 Anode Oven The cast house is also equipped with a natural gas fired anode oven for magnesium purification. This unit is rated at less than 5 MMBtu/hr. 6.2 Direct Fired Burners Less than 5 MMBtu/hr Analysis 6.2.1 Direct Fired Burners – Step 1 As with all burners, the NOX formed during combustion is primarily a function of residence time, oxygen level, and flame temperature, and can be minimized by controlling these elements in the design of the combustion equipment. The cast house furnaces, preheating equipment, and anode oven have all been specifically designed for the purpose they serve. A search of the RBLC and other RACT references allowed for a comparison of similar, but not equivalent units. The technologies identified as potential NO X reduction technologies are shown in the table below. Pollutant Control Technologies NOX Low NOX Burners (LNB)/ Ultra-Low NOX Burners (UNLB) Flue Gas Recirculation Selective Catalytic Reduction Good Combustion Practices (GCP) US Magnesium / Ozone RACT Analysis Trinity Consultants 6-2 6.2.2 Direct Fired Burners – Step 2 LNB/ULNB LNB/ULNB technology uses advanced burner design to reduce NO X formation through the restriction of oxygen, flame temperature, and/or residence time. To accommodate these design parameters, the physical footprint of the LNB/ULNB burner is often larger than a standard burner. When retrofitting units with LNB/ULNB, design companies typically reduce the number of burners and increase the heat output of each burner. Given the number of small burners within each of units considered, the replacement of the existing burners with those that utilize LNB/ULNB would require a full unit redesign. A full unit redesign is technically impractical and not further evaluated. Flue Gas Recirculation FGR involves the recycling of post-combustion air into the air-fuel mixture to reduce the available oxygen and help cool the burner flame. External FGR requires the use of ductwork to route a portion of the flue gas in the stack back to the burner windbox. Burners of this size typically do not utilize FGR as recirculation has been known to cause a “flame out” condition, in which the fuel valves remain open but the burner remains unlit. The accumulation of unburnt fuel presents an unacceptable safety hazard. As a result, the use of these technologies is technically infeasible. Selective Catalytic Reduction SCR has been applied to stationary source, fossil fuel-fired, combustion units for emission control since the early 1970s. In practice, SCR systems operate at efficiencies in the range of 70% to 90%.18 Generally, the optimum temperature ranges from 480°F to 800°F.19 The burners in use for these units typically exhaust at a temperature lower than required. Additionally, in a detailed review of all potential comparable sources in the CARB database, this technology was only applied to the aluminum industry. As a result, this technology is considered technically infeasible. Good Combustion Practices Good combustion practices currently in use at USM may include the use of low emitting fuels and proper maintenance of equipment, housekeeping, and general operating practices following manufacture recommendations where appropriate. 6.2.3 Direct Fired Burners – Steps 3 through 5 Given that good combustion practices are the only technically practicable control method, US M proposes that this is RACT. 18 OAQPS, EPA Air Pollution Control Cost Manual, Sixth Edition, EPA/424/B-02-001 (https://www.epa.gov/economic-and-cost- analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution)); January 2002 19 OAQPS, EPA Air Pollution Control Cost Manual, Sixth Edition, EPA/424/B-02-001 (https://www.epa.gov/economic-and-cost- analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution); January 2002 US Magnesium / Ozone RACT Analysis Trinity Consultants 7-1 7. SOLAR POND ENGINES 7.1 Diesel-Fired Prime Power Engines The diesel engines used on site at USM run direct drive water pumps for movement of fluids from one evaporation cell to another through various channels and trenches. Diesel engines are the second largest point source category of NOX emissions. Of the thirty-one (31) diesel engines on site, one is a 292 hp fire pump engine that charges the fire suppression system under emergency conditions (e.g., a plant fire during a power outage). The RACT analysis for the fire pump engine will be covered in section 10, as it is an emergency engine. The engines’ makes and models are listed in the table below: Table 7-1. Primary Diesel Engine on Site Engine Model Size Quantity Tier Rating Caterpillar 3406 420 14 2 Caterpillar 3208 225 13 1 Cummings C-9 285 1 3 Caterpillar 3306 225 1 1 Caterpillar 3304 90 1 1 7.1.1 Solar Pond Engines – Step 1 The least stringent emission rate allowable for RACT is any applicable limit under either New Source Performance Standards (NSPS – Part 60,) or National Emission Standards for Hazardous Air Pollutants (NESHAP – Part 63). Emission limits for diesel-fired engines are limited by EPA’s Tier program established in 40 CFR 1039, and are referenced by NSPS Subpart IIII, Standards of Performance for Stationary Compression Ignition Internal Combustion Engines.20 Under these regulations EPA requires manufacturers to reduce the emissions from engines produced after certain dates in a tiered fashion, based on the size and model year. In general, the higher the tier rating, the lower the emissions produced. The following sources were reviewed to identify available control technologies for the prime use, diesel- powered engines: ► EPA’s RACT, BACT, LAER Clearinghouse (RBLC) Database for Diesel Engines; ► California CARB; ► EPA’s Air Pollution Control Technology Fact Sheets. Available control methods for diesel-fired non-emergency engines include the following listed in the table below: 20 Non-Emergency regulated per 40 CFR 60.4201, Emergency regulated by 40 CFR 60.4202, and General Requirements regulated per 40 CFR 60.4203.1 US Magnesium / Ozone RACT Analysis Trinity Consultants 7-2 Pollutant Control Technologies NOX Limited Hours of Operation Good Combustion Practices (GCP) Use of a Tier Certified Engine Selective Catalytic Reduction 7.1.2 Solar Pond Engines – Step 2 Limited Hours of Operation One of the options to control the emissions of all pollutants released from generator engines is to limit the hours of operation for the equipment. The hours of operation are for these units are limited to 26.59 MMHp- hr per rolling 12-month period by AO condition II.B.4.b. Thus this control method is considered technically feasible. Good Combustion Practices GCP refer to the operation of engines at high combustion efficiency, which reduces the products of incomplete combustion. The engines are designed to achieve maximum combustion efficiency. The manufacturer has provided operation and maintenance manuals that detail the required methods to achieve the highest levels of combustion efficiency. GCP are considered technically feasible. Use of a Tier Certified Engine/Engine Design EPA noted that non-road engines were a significant source of emissions and began adopting emission standards for these emission units in 1994. Today, engines are required to meet certain emission limits, or tier ratings, based on the size and model year. This is achieved through strategic design elements, such as turbochargers, aftercoolers, positive crankcase ventilation, and high -pressure fuel injection. Replacing the existing engines with a tier certified engine of a higher rating is considered technically feasible, given the life span of the current engines. Selective Catalytic Reduction SCR systems introduce a liquid reducing agent such as ammonia or urea into an engine’s flue -gas stream prior to a catalyst. The catalyst reduces the temperature needed to initiate the reaction between the reducing agent and NOX to form nitrogen and water. Additional variations including NSCR and SNCR may be used but are not adapted to the air-to-fuel ratio necessary for the combustion of diesel, thus SCR remains the focus of this technical analysis. For SCR systems to function effectively, exhaust temperatures must be high enough (480 °F to 800 °F) to enable catalyst activation, which will be accounted for in operation.21 In summary, as the hot flue gas and reagent diffuse through the catalyst and contact activated catalyst sites, NO X in the flue gas chemically reduces to nitrogen and water. The heat of the flue gas provides energy for the reaction. The nitrogen, water vapor, and any other flue gas constituents then flow out of the SCR reactor. While SCR systems are an effective way at reducing NOX formation, they do present additional safety concerns with the use of ammonia or urea, and associated storage.22 Despite these concerns, they are considered technically feasible. 21 EPA Air Pollution Control Technology Fact Sheet for Selective Catalytic Reduction (SCR), EPA -452/F-03-032 22 EPA’s Air Pollution Control Technology Fact Sheet for Selective Catalytic Reduction. EPA-452/F-03-032. US Magnesium / Ozone RACT Analysis Trinity Consultants 7-3 7.1.3 Solar Pond Engines – Step 3 The remaining retrofit control technologies are ranked by their respective control effectiveness in the table below. Table 7-2. Primary Engine Controls Feasibility NOX Control Technologies Control Reduction Rank Limited Hours of Operation Variable 1 Use of Tier Certified Engines Up to 95% 1 Selective Catalytic Reduction (SCR) Up to 95% 1 Good Combustion Practices (GCP) Variable 2 7.1.4 Solar Pond Engines – Step 4 Currently, USM has one (1) Tier 3 Engine, fourteen (14) Tier 2 engines, and fifteen (15) Tier 1 engines. The cost analysis is separated into two evaluations. The first part of this section will evaluate the Tier 1 engines, and the second part will consider the Tier 2 and Tier 3 engines. For each of the economic feasibility analyses below USM followed the method described in EPA Cost Control Manual Chapter 2, Concepts and Methodology. Key to this analysis is the NO X emission rate reductions and interest rate. For this analysis USM has used a reduction rate equivalent to a decreased emission rate of 0.40 grams/kilowatt-hour (g/kW-hr) NO X with the installation of a Tier 4 equivalent engine.23 Additionally, USM assumed an average of 2,827 hours of operation each year to reflect AO condition II.B.4.b. Since the actual nominal interest rate for a project of this type is not readily available to USM, additional resources were reviewed to determine appropriate nominal interest rates for this industry sector and project type. One such resource was the Office of Management and Budget (OMB). For economic evaluations of the impact of federal regulations, the OMB uses an interest rate of 7%.24 A nominal interest rate of 7% has been referenced in EPA’s Cost Manual and has been commonly relied upon for control technology analyses for several decades as a representative average over time. Tier 1 Certified Engine Replacement Economic Feasibility Analysis The cost of replacing a 225 hp Tier 1 engine with an equivalent Tier 4 engine was evaluated for economic feasibility. After considering economic factors and other annual costs, the calculated cost per ton of NOx removed is $11,355 per ton removed.25 A full cost analysis is included in Appendix A. Tier 2 Certified Engine Replacement Economic Feasibility Analysis The cost of replacing a 420 hp Tier 2 engine with an equivalent Tier 4 engine was evaluated for economic feasibility. After considering economic factors and other annual costs, the calculated cost per ton of NOx removed is $15,016 per ton removed.26 A full cost analysis is included in Appendix A. 23 EPA Nonroad Compression-Ignition Engines: Exhaust Emission Standards, EPA-420-B-16-022, March 2016 24 OMB Circular A-4, https://obamawhitehouse.archives.gov/omb/circulars_a004_a -4/ 25 Cost estimate based on estimates from several vendors, sizes, and costs were provided and a linear interpolation was applied. 26 Cost estimate based on estimates from several vendors, sizes, and costs were provided and a linear interpolation was applied. US Magnesium / Ozone RACT Analysis Trinity Consultants 7-4 Tier 3 Certified Engine Replacement Economic Feasibility Analysis The cost of replacing a 285 hp Tier 3 engine with an equivalent Tier 4 engine was evaluated for economic feasibility. After considering economic factors and other annual costs, the calculated cost per ton of NOx removed is $26,405 per ton removed.27 A full cost analysis is included in Appendix A. Tier 3 Certified Engine SCR Retrofit Economic Feasibility Analysis The cost of adding an SCR system to a 285 hp Tier 3 engine was evaluated for economic feasibility. After considering economic factors and other annual costs , the calculated cost per ton of NOx removed is $30,212 per ton removed.28 A full cost analysis is included in Appendix A. The replacement of the current Tier 1 and Tier 2 engines with equivalent Tier 4 was determined to be technically and economically feasible. The replacement of the Tier 3 certified engine with an equivalent Tier 4 was determined to be economically infeasible. Furthermore, the addition of an SCR system to the Tier 3 engine was determined to be economically infeasible. 7.1.5 Solar Pond Engines – Step 5 For the Tier 1 and Tier 2 engines, USM proposes that replacing them with Tier 4 equivalent engines and GCP meet RACT. For the Tier 3 engine, USM proposes that GCP meet RACT. Since not all engines are currently in use, USM proposes the following timeline: ► Tier 1- Replace 6 of them over 3 years (5-Cat 3208 and 1 Cat 3306); ► Tier 2- Replace 6 of them over 3 years (6-CAT 3406); and ► Replacement of the balance of the Tier 1 and Tier 2 engines with Tier 4 before bringing them online. 27 Cost estimate based on estimates from several vendors, sizes, and costs were provided and a linear interpolation was applied. 28 Cost estimate based on estimates from several vendors, sizes, and costs were provided and a linear interpolation was applied. US Magnesium / Ozone RACT Analysis Trinity Consultants 8-1 8. FIRE PUMP ENGINE USM has one (1) diesel-fired emergency generator rated at 292 hp permitted that is for emergency use only (except for readiness testing and maintenance). Currently, this specific engine is out of commission and has been substituted with one of the Tier 2 certified 420 hp engines from the Solar Pond engines, discussed in Section 9. This analysis assumes that the USM will continue to utilize a 420 hp engine for this purpose as the use of a smaller unit would only increase technical challenges and reduce the potential for emission minimization. 8.1 Diesel Fired Engines NOX Technologies 8.1.1 Fire Pump Engines – Step 1 The least stringent emission rate allowable for RACT is any applicable limit under either NSPS or NESHAP. Emission limits for diesel-fired engines are limited by EPA’s Tier program established in 40 CFR 1039, and are referenced by NSPS Subpart IIII, Standards of Performance for Stationary Compression Ignition Internal Combustion Engines.29 Under these regulations EPA requires manufacturers to reduce the emissions from engines produced after certain dates in a tiered fashion, based on the size and model year. In general, the higher the tier rating, the lower the emissions produced. The engine evaluated under this RACT analysis is rated for emergency use only. In order to identify additional control technologies applied to emergency use engines , the following sources were reviewed: ► EPA’s RBLC Database for Diesel Generators (process 17.210 Small Internal Combustion Engines [<500 Hp] burning Fuel Oil);30 ► EPA’s Air Pollution Technology Fact Sheets; ► SCAQMD Example Permits; ► TCEQ’s BACT combustion workbook; and ► CARB Database. Available control methods for diesel-fired emergency engines include the following: ► Limited Hours of Operation; ► GCP; ► Use of a Tier Certified Engine; and ► Selective Catalyst Reduction (SCR). 8.1.2 Fire Pump Engines – Step 2 Limited Hours of Operation One of the options to control the emissions of all pollutants released from emergency generator engines is to limit the hours of operation for the equipment. Due to the designation of this equipment as emergency 29 Non-Emergency regulated per 40 CFR 60.4201, Emergency regulated by 40 CFR 60.4202, and General Requirements regulated per 40 CFR 60.4203. 30 Database accessed November 10, 2023. US Magnesium / Ozone RACT Analysis Trinity Consultants 8-2 equipment, only 100 hours of operation for maintenance and testing are permitted per NSPS Subpart IIII. Therefore, limiting hours of operation is considered technically feasible. Good Combustion Practices GCP refers to the operation of engines at high combustion efficiency, which reduces the products of incomplete combustion. Emergency generator engines are designed to achieve high combustion efficiency when maintained and operated according to the manufacturer’s written instructions. GCP are considered technically feasible. Use of a Tier Certified Engine/ Engine Design EPA noted that non-road engines were a significant source of emissions and began adopting emission standards for these emission units in 1994. Today, engines are required to meet certain emission limits, or tier ratings, based on the size and model year. This is achieved through strategic design elements, such as turbochargers, aftercoolers, positive crankcase ventilation, and high -pressure fuel injection. Per NSPS Subpart IIII section 60.4202, EPA only requires emergency use engines to meet Tier 2 or Tier 3 standards based on the size of the unit.31 EPA established Tier 3 standards for all units rated between 50 BHP and 750 BHP. The use of tier certified engines is considered technically feasible. Selective Catalytic Reduction SCR systems introduce a liquid reducing agent such as ammonia or urea into an engine’s flue -gas stream prior to a catalyst. The catalyst reduces the temperature needed to initiate the reaction between the reducing agent and NOX to form nitrogen and water. Additional variations including NSCR and SNCR may be used but are not considered standard industry practice and are not listed in the RBLC, thus SCR remains the focus of this technical analysis. For SCR systems to function effectively, exhaust temperatures must be high enough (480 °F to 800 °F) to enable catalyst activation, which will be accounted for in operation.32 For this reason, SCR control efficiencies are expected to be relatively low during the first 20 - 30 minutes after engine start up. Since operation of emergency engines typically only includes short duration runs for maintenance and testing, SCR is considered technically ineffective for maintenance and testing on small engines. Furthermore, for emergency engines under 600 HP, the use of an SCR is generally considered experimental. Due to the low emission reduction potential on an emergency unit of this size these controls are not standard practice for manufacturers.33 This leads to compromised equipment design and high potential for failure. Use of an SCR is considered technically infeasible. 8.1.3 Fire Pump Engines – Step 3 Effective control technologies for diesel engines are listed in the following table: 31 Emergency engines are regulated in 40 CFR 60.4202 which sites only 40 CFR 1039.104, 1039.105, and 1039.15. Tier 4 final and Tier 4 interim standards are given in 40 CFR 1039.101 and 1039.102, respectively, which are not referenced. 32 EPA Air Pollution Control Technology Fact Sheet for Selective Catalytic Reduction (SCR), EPA -452/F-03-032 33 Call conducted with engine manufacturer on April 13, 2022 US Magnesium / Ozone RACT Analysis Trinity Consultants 8-3 Table 8-1. Emergency Engine Controls Feasibility NOX Control Technologies Control Reduction Rank Use of a Tier Certified Engine Up to 95% 1 Limited Hours of Operation Variable 2 GCP Variable 3 8.1.4 Fire Pump Engines – Step 4 Tier 2 Certified Engine Replacement Cost Effectiveness The cost of replacing a 420 hp Tier 2 emergency engine with an equivalent Tier 4 engine was evaluated for economic feasibility using the same method described in Section 9.1.4. After considering economic factors and other annual costs, the calculated cost per ton of NOX removed is $61,800 per ton removed.34 A full cost analysis is included in Appendix A. Replacement of the current Tier 2 certified emergency engine with an equivalent Tier 4 certified engine was determined to be economically infeasible. 8.1.5 Fire Pump Engines – Step 5 USM proposes that limited hours of operation and GCP meet RACT for the fire pump engine. 34 Cost estimate based on estimates from several vendors, sizes, and costs were provided and a linear interpolation was applied. US Magnesium / Ozone RACT Analysis Trinity Consultants 9-1 9. BOILERS There are three (3) boilers permitted in USM’s AO. The 60 MMBtu/hr Riley Boiler has not been operational since March of 2022. Because there is no intention to bring the Riley Boiler back online, it will not be included in this analysis. The other two boilers are rated 63 and 84 MMBtu/hr and are part of USM’s lithium plant, which digests existing waste coupled with current waste streams to extract the available lithium ore. The NOX emissions from the plant come from natural gas combustion units. The natural gas fired boilers were installed in early 2020 and went through a BACT analysis when they were installed. They are ultra - low-NOX boilers (ULNB) capable of meeting a concentration limit of 9 ppmv NOX or less.35 Table 9-19-1 below summarizes the operating characteristics and installation date for each boiler. Table 9-1. Operating Characteristics and Installation Date Input Capacity (MMBtu/hr) Installed/Operating Characteristics Installation Date 63 - Utilize ULNB + FGR - 9 ppm 2020 84 - Utilize ULNB + FGR - 9 ppm 2020 9.1 Boiler NOX Technologies The NOX that will be formed during combustion is from two major mechanisms: thermal NO X and fuel NOX. Since natural gas is relatively free of fuel-bound nitrogen, the contribution of this second mechanism to the formation of NOX emissions in natural gas-fired equipment is minimal, leaving thermal NOX as the main source of NOX emissions. Thermal NO X formation is a function of residence time, oxygen level, and flame temperature, and can be minimized by controlling these elements in the design of the combustion equipment. 9.1.1 Boilers – Step 1 USM has reviewed the following sources to ensure all available control technologies have been identified: ► Proposed UDAQ rule R307-316, NOX Emission Controls for Natural-Gas Fired Boilers greater than 5 MMBtu/hr; ► EPA’s RBLC Database for Natural Gas External Combustion Units (process type 13.31);36 ► EPA’s Air Pollution Technology Fact Sheets; ► EPA’s CATC Alternative Control Techniques Document – NO X Emissions from Utility Boilers; ► NESHAP DDDDD – Major Sources: Industrial, Commercial, and Institutional Boilers and Process Heaters; ► NESHAP JJJJJJ – Industrial, Commercial, and Institutional Boilers at Area Sources; ► CARB Database; and ► Permits available online. 35 Per UDAQ Approval Order DAQE-AN107160050-20 dated April 20, 2020. 36 Database accessed November 10, 2023 US Magnesium / Ozone RACT Analysis Trinity Consultants 9-2 The results of these searches are summarized in the table below: Table 9-2. Medium Natural Gas Boilers NOX Controls and Emission Rates from RBLC37 The technologies identified as possible NOX reduction technologies are shown in the table below. Pollutant Control Technologies NOX Ultra-Low NOX Burners Flue Gas Recirculation Low NOx Burners Selective Catalytic Reduction Good Combustion Practices 37 Database accessed November 10, 2023 RBLCID Facility/Agency Name State Permit/Document Issued Control Method Averaging Time Case-by-Case AK-0083 KENAI NITROGEN OPERATIONS AK 01/06/2015  ACT 50 MMBTU/H Selective Catalytic Reduction 7 PPMV 3-HR AVG @ 15 % O2 BACT-PSD AR-0155 BIG RIVER STEEL LLC AR 11/07/2018  ACT 53.7 MMBTU/HR LOW NOX BURNERS COMBUSTION OF CLEAN FUEL GOOD COMBUSTION PRACTICES 0.035 LB/MMBTU NA BACT-PSD AR-0167 LION OIL COMPANY AR 12/01/2020  ACT 75 MMBtu/hr Ultra-low NOx burners and good combustion practice 3.5 LB/HR 3-HOUR AVERAGE BACT-PSD FL-0367 SHADY HILLS COMBINED CYCLE FACILITY FL 07/27/2018  ACT 60 MMBtu/hour low-NOx burners 0.05 LB/MMBTU NA BACT-PSD IN-0263 MIDWEST FERTILIZER COMPANY LLC IN 03/23/2017  ACT 70 MMBTU/HR GOOD COMBUSTION PRACTICES 12.611 LB/H 3 HOUR AVERAGE BACT-PSD IN-0359 NUCOR STEEL IN 03/30/2023  ACT 50 MMBtu/hr low NOx burners 0.035 LB/MMBTU BACT-PSD KY-0110 NUCOR STEEL BRANDENBURG KY 07/23/2020  ACT 54 MMBtu/hr Low-Nox Burner (Designed to maintain 0.15 lb/MMBtu in flameless mode and 0.25 lb/MMBtu in flame mode); and a Good Combustion and Operating Practices (GCOP) Plan. 158 LB/MMSCF FLAMELESS MODE BACT-PSD KY-0115 NUCOR STEEL GALLATIN, LLC KY 04/19/2021  ACT 50.4 MMBtu/hr The permittee must develop a Good Combustion and Operating Practices (GCOP) Plan. Also equipped with low-NOx burners. 35 LB/MMSCF NA BACT-PSD KY-0116 NOVELIS CORPORATION - GUTHRIE KY 07/25/2022  ACT 53 MMBtu/hr (total) Good Combustion & Operation Practices (GCOP) Plan 5.3 LB/HR MONTHLY AVERAGE BACT-PSD *LA-0315 G2G PLANT LA 05/23/2014  ACT 61 MMBTU/HR Ultra-Low NOx Burners (ULNB)2.44 LB/H HOURLY MAXIMUM BACT-PSD MI-0447 LBWL--ERICKSON STATION MI 01/07/2021  ACT 50 MMBTU/H Low NOx burners (LNB) or flue gas recirculation (FGR) along with good combustion practices. 30 PPM AT 3% O2; HOURLY BACT-PSD NY-0103 CRICKET VALLEY ENERGY CENTER NY 02/03/2016  ACT 60 MMBTU/H flue gas recirculation with low NOx burners 0.0085 LB/MMBTU 1 H LAER PA-0307 YORK ENERGY CENTER BLOCK 2 ELECTRICITY GENERATION PROJECT PA 06/15/2015  ACT 62.04 MCF/hr Good combustion practices, Ultra-Low NOx burners, FGR 0.0086 LB/MMBTU NA LAER TX-0851 RIO BRAVO PIPELINE FACILITY TX 12/17/2018  ACT 71.3 MMBTU/HR Low NOx burners and good combustion practices.0.162 LB/MMBTU NA BACT-PSD VA-0321 BRUNSWICK COUNTY POWER STATION VA 03/12/2013  ACT 66.7 MMBTU/H Dry Low NOx burner.9 PPMVD NA BACT-PSD -BAAQMD CA 8/4/2010 ≥50 MMBtu/hr Ultra Low NOx Burners & FGR NA BACT -SJVAPCD CA 11/30/2022 ≥20 MMBtu/hr Assumed SCR 0.003 LB/MMBTU NA BACT -SCAQMD CA 12/2/1999 33.9 MMBtu/hr SCR 7 ppm NA BACT -SCAQMD CA 3/22/2016 39.9 MMBtu/hr SCR 5 ppm 15 mins LAER -SCAQMD CA 5/19/2004 39 MMBtu/hr Ultra-Low NOx Burner & FGR 9 ppm NA BACT -TCEQ TX 10/1/2018 >40 MMBtu/hr Low NOx Burners & SCR 0.01 LB/MMBTU NA BACT Throughput Emission Limit NA US Magnesium / Ozone RACT Analysis Trinity Consultants 9-3 The control efficiencies along with technical and economic feasibility are compared to the presumptive norm established in proposed UDAQ rule R307-316, NOX Emission Controls for Natural-Gas Fired Boilers greater than 5 MMBtu/hr as they apply to the LCHTWP, which requires the following: ► NOX Emission Rate of 9 ppmv; and ► Operate and maintain in accordance with manufacturer's instruction. 9.1.2 Boilers – Step 2 To demonstrate a complete analysis, USM has evaluated the following technologies including both replacement burners and add-on controls. Ultra Low NOX Burners ULNB technology uses internal FGR which involves recirculating the hot O 2 depleted flue gas from the heater into the combustion zone using burner design features and fuel staging to reduce NO X. ULNB most commonly uses an internal induced draft to reach the desired emission limitations. This technology is listed in the RBLC search as a technically feasible control technology. An ULNB can achieve an emission rate of approximately 9 ppm or 0.011 lb/MMBtu. UDAQ has established this as the NOX emission standard through proposed boiler rules R307-315 and 316 as the use of an ULNB is the most common method utilized to meet a 9 ppmv emission guarantee.38 Currently, both units use this technology. Flue Gas Recirculation FGR is frequently used with both LNB and ULNB burners. FGR involves the recycling of post -combustion air into the air-fuel mixture to reduce the available oxygen and help cool the burner flame. External FGR requires the use of ductwork to route a portion of the flue gas in the stack back to the burner windbox; FGR can be either forced draft (where hot side fans are used) or induced draft. This technology is listed in the RBLC search as technically feasible and is often incorporated into the ULNB design at the manufacturer’s discretion. As a result this technology is not further evaluated. Low NOX Burners LNB technology uses advanced burner design to reduce NOX formation through the restriction of oxygen, flame temperature, and/or residence time. There are two general types of LNB: staged fuel and staged air burners. In a stage fuel LNB, the combustion zone is separated into two regions. The first region is a le an combustion region where a fraction of the fuel is supplied with the total quantity of combustion air. Combustion in this zone takes place at substantially lower temperatures than a standard burner. In the second combustion region, the remaining fuel is injected and combusted with leftover oxygen from the first region. A staged air burner begins with full fuel but only partial combustion air, and then adds the remaining combustion air in the second combustion region. These techniques reduce the formation of thermal NOX. This technology is listed in the RBLC search as a technically feasible control technology. Selective Catalytic Reduction SCR has been applied to stationary, fossil fuel-fired combustion units for emission control since the early 1970s. It has been applied to utility and industrial boilers, process heaters, and combined cycle gas turbines. SCR can be applied as a stand-alone NOX control or with other technologies such as combustion controls. The reagent reacts selectively with the flue gas NOX within a specific temperature range and in the 38 Effective July 10, 2023 US Magnesium / Ozone RACT Analysis Trinity Consultants 9-4 presence of the catalyst and oxygen to reduce the NO X into molecular nitrogen (N2) and water vapor (H2O).39 The optimum operating temperature is dependent on the type of catalyst and the flue gas composition. Generally, the optimum temperature ranges from 480 °F to 800 °F.40 In practice, SCR systems operate at efficiencies in the range of 70% to 90%.41 SCR is listed in the RBLC search as technically feasible. Good Combustion Practices The use of good combustion practices (GCP) usually includes the following components: (1) proper fuel mixing in the combustion zone; (2) high temperatures and low oxygen levels in primary zone; (3) Overall excess oxygen levels high enough to complete combustion while maximizing boiler efficiency, a nd (4) sufficient residence time to complete combustion. GCP is accomplished through boiler design as it relates to time, temperature, and turbulence, and boiler operation as it related to excess oxygen levels. GCP is considered technically feasible. 9.1.3 Boilers – Step 3 Based on an RBLC search the following technologies are currently being used in industry and are ranked based on which technology can achieve the lowest emission rate. Table 9-3. Emergency Engine Controls Feasibility NOX Control Technologies Emission Factor (ppm) Rank ULNB + SCR 3 ppm 1 ULNB or LNB + FGR 9 ppm 2 LNB 30 ppm 3 FGR 187 ppm 4 9.1.4 Boilers – Step 4 Selective Catalytic Reduction The cost of retrofitting the boilers with and SCR was evaluated for economic feasibility using the same method described in Section 9.1.4. It was determined that the cost per ton of NOX removed would be $80,921 for the 84 MMBtu/hr boiler and $103,482 for the 63 MMBtu/hr boiler. USM proposes the use of an SCR as economically infeasible and will eliminate SCR from RACT consideration. A full cost analysis is included in Appendix A. 39 EPA Air Pollution Control Technology Fact Sheet, Selective Catalytic Reduction (SCR) 40 OAQPS, EPA Air Pollution Control Cost Manual, Sixth Edition, EPA/424/B-02-001 (https://www.epa.gov/economic-and-cost- analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution); January 2002 41 OAQPS, EPA Air Pollution Control Cost Manual, Sixth Edition, EPA/424/B-02-001 (https://www.epa.gov/economic-and-cost- analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution); January 2002 US Magnesium / Ozone RACT Analysis Trinity Consultants 9-5 9.1.5 Boilers – Step 5 Both units are ULNB and have a permitted NOX emission rate of 9 ppm (0.25 lb/hr), each.42 The presumptive norm for the units in question is 9 ppmv as well as operate and maintain in accordance with manufacturer’s instructions. According to R307-316, a 9ppm of NOX emission standard for boilers >5.0 MMBtu, is the presumptive norm.43 Additionally, GCP will continue to be employed. Since all economically feasible controls are proposed and the unit meets the presumptive norm, USM proposes these units meet RACT as currently operated. 42 AO AN103540025-13, Permit Condition II.B.2.c 43 Utah DAQ R307-316 NOx Emission Controls for Natural Gas-Fired Boilers Greater Than 5.0 MMBtu US Magnesium / Ozone RACT Analysis Trinity Consultants 10-1 10. LITHIUM PLANT SPRAY DRYERS USM’s lithium plant digests existing waste coupled with current waste streams to extract the available lithium ore. NOX emissions from the plant come from a 100 MMBtu natural gas fired burner set consisting of two 50 MMBtu burners, and an additional 50 MMBtu leach evaporator natural gas fired burner. They are low-NOX boilers (LNB) capable of meeting a concentration limit of 30 ppm NOX or less44. 10.1 Spray Dryer NOX Technologies The NOX that will be formed during combustion is from two major mechanisms: thermal NO X and fuel NOX. Since natural gas is relatively free of fuel-bound nitrogen, the contribution of this second mechanism to the formation of NOX emissions in natural gas-fired equipment is minimal, leaving thermal NOX as the main source of NOX emissions. Thermal NO X formation is a function of residence time, oxygen level, and flame temperature, and can be minimized by controlling these elements in the design of the combustio n equipment. 10.1.1 Lithium Spray Dryers – Step 1 USM has reviewed the following sources to ensure all available control technologies have been identified , which is the same as for the natural gas boilers in Section 11 of this document: ► Proposed UDAQ rule R307-316, NOX Emission Controls for Natural-Gas Fired Boilers greater than 5 MMBtu/hr; ► EPA’s RBLC Database for Natural Gas External Combustion Units (process type 13.31);45 ► EPA’s Air Pollution Technology Fact Sheets; ► EPA’s CATC Alternative Control Techniques Document – NO X Emissions from Utility Boilers; ► NESHAP DDDDD – Major Sources: Industrial, Commercial, and Institutional Boilers and Process Heaters; ► NESHAP JJJJJJ – Industrial, Commercial, and Institutional Boilers at Area Sources; ► CARB Database; and ► Permits available online. The technologies identified as possible NOX reduction technologies are shown in the table below. Pollutant Control Technologies NOX Ultra-Low NOX Burners Flue Gas Recirculation Selective Catalytic Reduction Low NOx Burners Good Combustion Practices 44 Per UDAQ Approval Order DAQE-AN107160050-20 dated April 20, 2020. 45 Database accessed November 10, 2023 US Magnesium / Ozone RACT Analysis Trinity Consultants 10-2 10.1.2 Lithium Spray Dryers – Step 2 To demonstrate a complete analysis, USM has evaluated the following technologies including both replacement burners and add-on controls. Ultra Low NOX Burners ULNB technology uses internal FGR which involves recirculating the hot O 2 depleted flue gas from the heater into the combustion zone using burner design features and fuel staging to reduce NO X. An ULNB is most commonly using an internal induced draft to reach the desired emission limitations. This technology is listed in the RBLC search as a technically feasible control technology. An equipment vendor was contacted to evaluate the feasibility of an ULNB. ULNB are considered technically infeasible due to the following operating requirements for these burners: 1. Process Temperature requirement of 1,500 °F at site elevation of 4,220 feet above sea level: USM evaluated the OptimaTM SLS ULN burner; however, the manufacturer’s specification sheet states that the ULNB is limited to a maximum application temperature of 1,000 °F and the manufacturer confirmed that limitation at the site elevation. 2. Turndown ratio: The ULNB is limited to a 5:1 turndown ratio compared to a 13:1 turndown for the existing low NOX burner. A 13:1 turndown ratio is more efficient for startups and lower production rate operation. 3. Technical design/system reliability: For USM’s application, the burner will be fired into a combustion chamber which is attached to a spray tower where the hot gases from the burner contact a cool brine. Changes in brine flow, distribution of flow, and the condition of spray tower internals will affect the back pressure on the burner. An ULNB would be much more sensitive to fluctuations in back pressure, which would be unacceptable for the continuous operation of the lithium plant. The equipment vendor and burner manufacturer stated that ULNB are typically utilized in boiler burner applications, which are fired into a stagnant chamber (no process airflow), are sheet metal commercial duty burners and have limited turndown. The equipment vendor further stated that they are not aware of any industrial duty burners capable of the 9-15 ppm NOX emissions level for process air heating applications. Flue Gas Recirculation FGR is frequently used with both LNB and ULNB burners. External FGR requires the use of ductwork to route a portion of the flue gas in the stack back to the burner windbox; FGR can be either forced draft (where hot side fans are used) or induced draft FGR involves the recycling of post-combustion air into the air-fuel mixture to reduce the available oxygen and lowers the burner flame temperature, which reduces thermal NOX formation. For example, a typical procedure of adding 10% of flue gas into the burner flame reduces flame temperature by 7%.46. Because a process-specific temperature of 1,500 °F is required, the addition of a control technology that functions by lowering combustion temperature is considered technically infeasible. 46 Module 106: Natural Gas Boiler Flue Gas Recirculation to Reduce NOx Emissions (https://www.cibsejournal.com/cpd/modules/2016-12-nox/) US Magnesium / Ozone RACT Analysis Trinity Consultants 10-3 Selective Catalytic Reduction SCR has been applied to stationary, fossil fuel-fired combustion units for emission control since the early 1970s. It has been applied to utility and industrial boilers, process heaters, and combined cycle gas turbines. SCR can be applied as a stand-alone NOX control or with other technologies such as combustion controls. The reagent reacts selectively with the flue gas NOX within a specific temperature range and in the presence of the catalyst and oxygen to reduce the NO X into molecular nitrogen (N2) and water vapor (H2O).47 The optimum operating temperature is dependent on the type of catalyst and the flue gas composition. Generally, the optimum temperature ranges from 480 °F to 800 °F.48 In practice, SCR systems operate at efficiencies in the range of 70% to 90%.49 There are two ways SCRs can be implemented: in-combustion NOX reduction, and exhaust aftertreatment. In the process of in-combustion NOX reduction, ammonia is injected directly into the combustion chamber which poses the risk of product contamination during the drying process. For this reason, in -combustion NOX reduction is considered technically infeasible. The exhaust temperature of the existing LNBs is 155 °F. For exhaust after treatment to be functional, the exhaust temperature of the burners would have to be raised to optimal levels for operation of at least 480 °F, requiring an additional burner. For this reason, exhaust after treatment is also considered technically infeasible. Low NOX Burners LNB technology uses advanced burner design to reduce NOX formation through the restriction of oxygen, flame temperature, and/or residence time. There are two general types of LNB: staged fuel and staged air burners. In a stage fuel LNB, the combustion zone is separated into two regions. The first region is a le an combustion region where a fraction of the fuel is supplied with the total quantity of combustion air. Combustion in this zone takes place at substantially lower temperatures than a standard burner. In the second combustion region, the remaining fuel is injected and combusted with leftover oxygen from the first region. A staged air burner begins with full fuel but only partial combustion air, and then adds the remaining combustion air in the second combustion region. These techniques reduce the formation of thermal NO X. This technology is listed in the RBLC search as a technically feasible control technology. Currently, the Lithium Plant Spray Dryers are LNB. Good Combustion Practices The use of good combustion practices (GCP) usually includes the following components: (1) proper fuel mixing in the combustion zone; (2) high temperatures and low oxygen levels in primary zone; (3) Overall excess oxygen levels high enough to complete combustion while maximizing boiler efficiency, a nd (4) sufficient residence time to complete combustion. GCP is accomplished through boiler design as it relates to time, temperature, and turbulence, and burner operation as it related to excess oxygen levels. GC P is considered technically feasible. 47 EPA Air Pollution Control Technology Fact Sheet, Selective Catalytic Reduction (SCR) 48 OAQPS, EPA Air Pollution Control Cost Manual, Sixth Edition, EPA/424/B-02-001 (https://www.epa.gov/economic-and-cost- analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution); January 2002 49 OAQPS, EPA Air Pollution Control Cost Manual, Sixth Edition, EPA/424/B-02-001 (https://www.epa.gov/economic-and-cost- analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution); January 2002 US Magnesium / Ozone RACT Analysis Trinity Consultants 10-4 10.1.3 Lithium Spray Dryers – Steps 3 through 5 The only technically feasible control technologies for the Lithium Plant Spray Dryers are LNB and GCP. The manufacturer guarantee for the lithium dryer burners is 30 ppm of NOx or 0.037 lb/MMBtu. USM proposes the Lithium Plant Spray Dryers currently meet RACT. US Magnesium / Ozone RACT Analysis Trinity Consultants A-1 APPENDIX A. COST ANALYSES Appendix A. Cost Analysis Table A-1. Engine HP Calculation Caterpillar 3406 14 420 5880 Caterpillar 3208 13 225 2925 Cummings C-9 1 285 285 Caterpillar 3306 1 225 225 Caterpillar 3304 1 90 90 9,405 Table A-2. Hours of Operation of Engines Category Value Units Permitted operation 26,590,000 hp-hrs Calculated Hours of Operation 2,827 hours Fire pump Engine 100 hours Engine Model Quantity Size (HP)Total HP Total HP US Magnesium LLC A-1 Trinity Consultants June 2024 Appendix A. Cost Analysis Table B-1. Cost Evaluation for Replacement Engine, Tier 1 to Tier 4- General Information Parameter Value Notes Duty (bhp)225 Manufacturer specifications. Duty (kW)168 Approximate conversion from hp to kW is 1.341 hp/kW. Operating hours (hr/yr)2827 See Table A-2, based on permit limit Tier I Emission NOX Rate (g/kw-hr)9.20 EPA "Nonroad Compression-Ignition Engines: Exhaust Emission Standards", Office of Transportation and Air Quality, U.S. EPA-420-B-16-022, March 2016 Tier I Emissions NOX (tpy)4.81 Total emission rate based on operating hours Tier IV Emission NOX Rate (g/kW-hr)0.40 EPA "Nonroad Compression-Ignition Engines: Exhaust Emission Standards", Office of Transportation and Air Quality, EPA-420-B-16-022 March 2016 Tier IV Final Emissions NOX (tpy)0.21 Equipment Life Expectancy (Years)15 Exemption to replacement engine provisions codified in 40 CFR 60.4210(i) Interest Rate (%)7.00%OMB Circular A-4, https://obamawhitehouse.archives.gov/omb/circulars_a004_a-4/ Table B-2. Cost Evaluation for Replacement Engine, Tier 1 to Tier 4 - Capital Investment Parameter Value Notes Total Capital Investment ($)$95,800 Cost estimate from a reliable vendor for the purchase of an equivalent replacement Tier IV Certified Engine. Capital Recovery Factor (CRF)0.1098 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Equation 2.8a Capital Recovery Cost (CRC)$10,518 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Equation 2.8 Table B-3. Cost Evaluation for Replacement Engine, Tier 1 to Tier 4 - Annual Operating Costs Parameter Value Notes Operating Labor, Maintenance, Brake Specific Fuel Consumption, and Catalyst Maintenance $113 $/hp, U.S. EPA Alternative Control Techniques Document: Stationary Diesel Engines (U.S. EPA Contract No. EP-D-07-019) Published March 5, 2010, Cost values are cited to be from 2005 and have been adjusted for operating hours. Inflation Factor 1.64 Based on U.S. Bureau of Labor Statistics CPI Inflation Calculator from January of 2005 to April of 2024. https://www.bls.gov/data/inflation_calculator.htm Total Direct Operating Costs $41,730 Table B-4. Cost Evaluation for Replacement Engine, Tier 1 to Tier 4 - Annual Operating, Insurance, Tax, and Other Costs Parameter Value Notes Total Annual Cost $52,248 Sum of Capital Recovery Cost, Total Direct Operating Costs, Insurance, Tax and Other Annual Costs. NOX Removed (tpy)4.60 Cost per Ton of NOX Removed ($/ton)$11,355 Process Information Economic Factors Direct Operating Costs NOX Cost Per Ton Removed US Magnesium LLC A-2 Trinity Consultants June 2024 Appendix A. Cost Analysis Table C-1. Cost Evaluation for Replacement Engine, Tier 2 to Tier 4 - General Information Parameter Value Notes Duty (bhp)420 Manufacturer specifications. Duty (kW)313 Approximate conversion from hp to kW is 1.341 hp/kW. Operating hours (hr/yr)2827 See Table A-2, based on permit limit Tier II Emission NOX Rate (g/kw-hr)6.40 EPA "Nonroad Compression-Ignition Engines: Exhaust Emission Standards", Office of Transportation and Air Quality, U.S. EPA-420-B-16-022, March 2016 Tier II Emissions NOX (tpy)6.25 Total emission rate based on operating hours Tier IV Emission NOX Rate (g/kW-hr)0.40 EPA "Nonroad Compression-Ignition Engines: Exhaust Emission Standards", Office of Transportation and Air Quality, EPA-420-B-16-022 March 2016 Tier IV Final Emissions NOX (tpy)0.39 Equipment Life Expectancy (Years)15 Exemption to replacement engine provisions codified in 40 CFR 60.4210(i) Interest Rate (%)7.00%OMB Circular A-4, https://obamawhitehouse.archives.gov/omb/circulars_a004_a-4/ Table C-2. Cost Evaluation for Replacement Engine, Tier 2 to Tier 4 - Capital Investment Parameter Value Notes Total Capital Investment ($)$91,500 Cost estimate from a reliable vendor for the purchase of an equivalent replacement Tier IV Certified Engine. Capital Recovery Factor (CRF)0.1098 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Equation 2.8a Capital Recovery Cost (CRC)$10,046 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Equation 2.8 Table C-3. Cost Evaluation for Replacement Engine, Tier 2 to Tier 4 - Annual Operating Costs Parameter Value Notes Operating Labor, Maintenance, Brake Specific Fuel Consumption, and Catalyst Maintenance $113 $/hp, U.S. EPA Alternative Control Techniques Document: Stationary Diesel Engines (U.S. EPA Contract No. EP-D-07-019) Published March 5, 2010, Cost values are cited to be from 2005 and have been adjusted for operating hours. Inflation Factor 1.64 Based on U.S. Bureau of Labor Statistics CPI Inflation Calculator from January of 2005 to April of 2024. https://www.bls.gov/data/inflation_calculator.htm Total Direct Operating Costs $77,896 Table C-4. Cost Evaluation for Replacement Engine, Tier 2 to Tier 4 - Annual Operating, Insurance, Tax, and Other Costs Parameter Value Notes Total Annual Cost $87,942 Sum of Capital Recovery Cost, Total Direct Operating Costs, Insurance, Tax and Other Annual Costs. NOX Removed (tpy)5.86 Cost per Ton of NOX Removed ($/ton)$15,016 Process Information Economic Factors Direct Operating Costs NOX Cost Per Ton Removed US Magnesium LLC A-3 Trinity Consultants June 2024 Appendix A. Cost Analysis Table D-1. Cost Evaluation for Replacement Engine, Tier 3 to Tier 4 - General Information Parameter Value Notes Duty (bhp)285 Manufacturer specifications. Duty (kW)213 Approximate conversion from hp to kW is 1.341 hp/kW. Operating hours (hr/yr)2827 See Table A-2, based on permit limit Tier III Emission NOX Rate (g/kw-hr)4.00 EPA "Nonroad Compression-Ignition Engines: Exhaust Emission Standards", Office of Transportation and Air Quality, U.S. EPA-420-B-16-022, March 2016 Tier III Emissions NOX (tpy)2.65 Total emission rate based on operating hours Tier IV Emission NOX Rate (g/kW-hr)0.40 EPA "Nonroad Compression-Ignition Engines: Exhaust Emission Standards", Office of Transportation and Air Quality, EPA-420-B-16-022, March 2016 Tier IV Final Emissions NOX (tpy)0.26 Equipment Life Expectancy (Years)15 Exemption to replacement engine provisions codified in 40 CFR 60.4210(i) Interest Rate (%)7.00%OMB Circular A-4, https://obamawhitehouse.archives.gov/omb/circulars_a004_a-4/ Table D-2. Cost Evaluation for Replacement Engine, Tier 3 to Tier 4 - Capital Investment Parameter Value Notes Total Capital Investment ($)$92,000 Cost estimate from a reliable vendor for the purchase of an equivalent replacement Tier IV Certified Engine. Capital Recovery Factor (CRF)0.1098 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Equation 2.8a Capital Recovery Cost (CRC)$10,101 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Equation 2.8 Table D-3. Cost Evaluation for Replacement Engine, Tier 3 to Tier 4 - Annual Operating Costs Parameter Value Notes Operating Labor, Maintenance, Brake Specific Fuel Consumption, and Catalyst Maintenance $113 $/hp, U.S. EPA Alternative Control Techniques Document: Stationary Diesel Engines (U.S. EPA Contract No. EP-D-07-019) Published March 5, 2010, Cost values are cited to be from 2005 and have been adjusted for operating hours. Inflation Factor 1.64 Based on U.S. Bureau of Labor Statistics CPI Inflation Calculator from January of 2005 to April of 2024. https://www.bls.gov/data/inflation_calculator.htm Total Direct Operating Costs $52,858 Table D-4. Cost Evaluation for Replacement Engine, Tier 3 to Tier 4 - Annual Operating, Insurance, Tax, and Other Costs Parameter Value Notes Total Annual Cost $62,959 Sum of Capital Recovery Cost, Total Direct Operating Costs, Insurance, Tax and Other Annual Costs. NOX Removed (tpy)2.38 Cost per Ton of NOX Removed ($/ton)$26,405 Process Information Economic Factors Direct Operating Costs NOX Cost Per Ton Removed US Magnesium LLC A-4 Trinity Consultants June 2024 Appendix A. Cost Analysis Table E-1. Cost Evaluation for Tier 3 + SCR add on - General Information Parameter Value Notes Duty (bhp)285 Manufacturer specifications. Duty (kW)213 Approximate conversion from hp to kW is 1.341 hp/kW. Operating hours (hr/yr)2827 See Table A-2, based on permit limit Tier III Emission NOX Rate (g/kw-hr)4.00 NMHC+NOx emission factor from Tier III (g/kw-hr) Tier III Emissions NOX (tpy)2.65 Total emission rate based on operating hours Tier IV Emission NOX Rate (g/kW-hr)0.40 U.S. EPA Office of Transportation and Air Quality (U.S. EPA-420-B-16-022) published March 2016, Interim Standard used as it is in the same form as the Tier IV published standard, NMHC is anticipated to be a minor component of the emission factor. Tier IV Final Emissions NOX (tpy)0.26 Equipment Life Expectancy (Years)15 Exemption to replacement engine provisions codified in 40 CFR 60.4210(i) Interest Rate (%)7.00%OMB Circular A-4, https://obamawhitehouse.archives.gov/omb/circulars_a004_a-4/ Table E-2. Cost Evaluation for Tier 3 + SCR add on - Capital Investment Parameter Value Notes Total Capital Investment ($)$160,000 Cost estimate based on vendor estimate. Cost in 2023 dollars. See Tables F-1 through F-3. Capital Recovery Factor (CRF)0.1098 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Equation 2.8a Capital Recovery Cost (CRC)$17,567 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Equation 2.8 Table E-3. Cost Evaluation for Tier 3 + SCR add on - Annual Operating, Insurance, Tax, and Other Costs Parameter Value Notes Operating Labor, Maintenance, Brake Specific Fuel Consumption, and Catalyst Maintenance $113 $/hp, U.S. EPA Alternative Control Techniques Document: Stationary Diesel Engines (U.S. EPA Contract No. EP-D-07-019) Published March 5, 2010, Cost values are cited to be from 2005 and have been adjusted for operating hours. Inflation Factor 1.69 Based on U.S. Bureau of Labor Statistics CPI Inflation Calculator from January of 2005 to October of 2023. https://www.bls.gov/data/inflation_calculator.htm Total Direct Operating Costs $54,469 Table E-4. BACT Control Cost Evaluation for Tier 3 + SCR add on - Annual Operating, Insurance, Tax, and Other Costs Parameter Value Notes Total Annual Cost $72,036 Sum of Capital Recovery Cost, Total Direct Operating Costs, Insurance, Tax and Other Annual Costs. NOX Removed (tpy)2.38 Cost per Ton of NOX Removed ($/ton)$30,212 Process Information Economic Factors Direct Operating Costs NOX Cost Per Ton Removed US Magnesium LLC A-5 Trinity Consultants June 2024 Appendix A. Cost Analysis Table G-1. Cost Evaluation for Replacement Emergency Engine, Tier 2 to Tier 4, Emergency Use - General Information Parameter Value Notes Duty (bhp)420 Manufacturer specifications. Duty (kW)313 Approximate conversion from hp to kW is 1.341 hp/kW. Operating hours (hr/yr)100 100 hours per NSPS IIII Tier II Emission NOX Rate (g/kw-hr)6.40 Tier II NMHC+NOx emission factor from Tier II (g/kw-hr), NMHC assumed to be minor component of emisson factor Tier II Emissions NOX (tpy)0.22 Total emission rate based on operating hours Tier IV Emission NOX Rate (g/kW-hr)0.40 EPA "Nonroad Compression-Ignition Engines: Exhaust Emission Standards", Office of Transportation and Air Quality, EPA-420-B-16-022, March 2016. Tier IV Final Emissions NOX (tpy)0.01 Equipment Life Expectancy (Years)15 Exemption to replacement engine provisions codified in 40 CFR 60.4210(i) Interest Rate (%)7.00%OMB Circular A-4, https://obamawhitehouse.archives.gov/omb/circulars_a004_a-4/ Table G-2. Cost Evaluation for Replacement Engine, Tier 2 to Tier 4, Emergency Use - Capital Investment Parameter Value Notes Total Capital Investment ($)$91,500 Cost estimate from a reliable vendor for the purchase of an equivalent replacement Tier IV Certified Engine. Capital Recovery Factor (CRF)0.1098 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Equation 2.8a Capital Recovery Cost (CRC)$10,046 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Equation 2.8 Table G-3. Cost Evaluation for Replacement Engine, Tier 2 to Tier 4, Emergency Use - Annual Operating Costs Parameter Value Notes Operating Labor, Maintenance, Brake Specific Fuel Consumption, and Catalyst Maintenance $4 $/hp, U.S. EPA Alternative Control Techniques Document: Stationary Diesel Engines (U.S. EPA Contract No. EP-D-07-019) Published March 5, 2010, Cost values are cited to be from 2005 and have been adjusted for operating hours. Inflation Factor 1.64 Based on U.S. Bureau of Labor Statistics CPI Inflation Calculator from January of 2005 to April of 2024. https://www.bls.gov/data/inflation_calculator.htm Total Direct Operating Costs $2,755 Table G-4. Cost Evaluation for Replacement Engine, Tier 2 to Tier 4, Emergency Use - Annual Operating, Insurance, Tax, and Other Costs Parameter Value Notes Total Annual Cost $12,801 Sum of Capital Recovery Cost, Total Direct Operating Costs, Insurance, Tax and Other Annual Costs. NOX Removed (tpy)0.21 Cost per Ton of NOX Removed ($/ton)$61,800 Process Information Economic Factors Direct Operating Costs NOX Cost Per Ton Removed US Magnesium LLC A-6 Trinity Consultants June 2024 Appendix A. Cost Analysis Table H-1. RACT Control Cost Evaluation for 84 MMBTU/hr Boiler SCR Retrofit - General Information Parameter Value Notes Heat Input (MMBtu/hr)84.0 Hours of operation (hr/yr)8760 Assume annual operation Current Emission Rate (tpy)3.45 Estimated Removal Efficiency 70%EPA Air Pollution control Technology Fact Sheet Estimated Emission Rate (tpy)1.04 Post SCR control Estimated Ammonia Usage (lb/hr)1.14 Calculated using U.S. EPA Cost Control Manual Section 4 Chapter 2 Selective Catalytic Reduction Costs equation 2.35 Cost of Ammonia Reagent ($/lb)0.27 Quote from Thatcher ($1.38/gallon for 19% ammonia) Cost of Catalyst ($/ft3)$227.00 U.S. Environmental Protection Agency (EPA). Documentation for EPA’s Power Sector Modeling Platform v6 Using the Integrated Planning Model. Office of Air and Radiation. May 2018. Available at: https://www.epa.gov/airmarkets/documentation-epas-power-sector-modeling-platform-v6 Operator ($/hour)$28.50 Utah Department of Workforce Services, Occupational Wages by Region, Median Annual Wage for Installation/Maintenance/Repair, Machinery cited $59,300. Assumed a standard working year contains 2,080 hours. Equipment Life Expectancy (Years)23 U.S. EPA Cost Control Manual Section 4 Chapter 2 Selective Catalytic Reduction Costs average life expectancy for industrial boilers Interest Rate (%)7.00%OMB Circular A-4, https://obamawhitehouse.archives.gov/omb/circulars_a004_a-4/ Table H-2. RACT Control Cost Evaluation for 84 MMBTU/hr Boiler SCR Retrofit - Capital Investment Parameter Value Notes Total Increase in Capital Investment ($)$568,000 Cost estimate based on communication with CECO Environmental December 2023 Direct Installation Costs $170,400 U.S. EPA's Alternative Control Techniques Document -- NOx Emissions from Industrial/Commercial/Institutional (ICI) Boilers, Section 6.1.1.2 Direct Installation Costs Indirect Installation Costs $187,440 U.S. EPA's Alternative Control Techniques Document -- NOx Emissions from Industrial/Commercial/Institutional (ICI) Boilers, Section 6.1.1.3 Indirect Installation Costs Contingency $142,000 This cost was added as the total equipment cost was obtained anonymously and a minimum equipment cost was provided. Freight $28,400 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Table 2.4 Sales Tax $17,040 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Table 2.4 Instrumentation $56,800 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Table 2.4 Capital Recovery Factor (CRF)0.0895 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Equation 2.8a Capital Recovery Cost (CRC)$104,766 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Equation 2.8 Process Information Labor Costs Economic Factors US Magnesium LLC A-7 Trinity Consultants June 2024 Appendix A. Cost Analysis Table H-3. RACT Control Cost Evaluation for 84 MMBTU/hr Boiler SCR Retrofit - Annual Operating, Insurance, Tax, and Other Costs Parameter Value Notes Operating Labor $35,369 U.S. EPA Cost Control Manual Section 4 Chapter 2 Selective Catalytic Reduction Costs estimates 4 hours per day of Operating and Supervisory Labor. The estimate presented utilizes Section 1, Chapter 2's assumption tat 15% of operating labor is supervisory labor Supervisory Labor $6,242 Assumed to be 15% of operating Labor, U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Section 2.6.5.2 Maintenance Labor and Materials $2,840 U.S. EPA Cost Control Manual Section 4 Chapter 2 Selective Catalytic Reduction Costs estimates maintenance costs to be 0.5 percent of the total capital investment. Annual Reagent Costs $626 U.S. EPA Cost Control Manual Section 4 Chapter 2 Selective Catalytic Reduction Costs equation 2.58, assumed 2,000 hours of operation consistent with the reduced heat load Annual Catalyst Costs $6,538 Catalyst size calculated based on information provided in U.S. EPA's Air Pollution Control Technology Fact Sheet for SCR (EPA-452/F-03-032). Assumed Catalyst life of 5 years. Total Direct Operating Costs $51,613 Sum of Direct Operating Costs on an Annual Basis Overhead $26,670 Assumed to be 60% of there total Direct Operating Costs, U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Section 2.6.5.7 Property Tax $5,680 Assumed to be 1% of the Total Capital Investment, U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Section 2.6.5.8 Increase in Insurance $5,680 Assumed to be 1% of the Total Capital Investment, U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Section 2.6.5.8 Administrative Charges $1,095 U.S. EPA Cost Control Manual Section 4, Chapter 2, Equation 2.69 Total Insurance, Tax, and Other Annual Costs $39,125 Sum of Insurance, Tax, and Other Annual Costs Table H-4. RACT Control Cost Evaluation for 84 MMBTU/hr Boiler SCR Retrofit - Total Annual Cost & Cost per Ton Removed Parameter Value Notes Total Annual Cost $195,505 Sum of Capital Recovery Cost, Total Direct Operating Costs, Insurance, Tax and Other Annual Costs. NOX Removed (tpy)2.42 Cost per Ton of NOX Removed $80,921 NOX Cost Per Ton Removed Direct Operating Costs Insurance, Tax, and Other Annual Costs US Magnesium LLC A-8 Trinity Consultants June 2024 Appendix A. Cost Analysis Table I-1. RACT Control Cost Evaluation for 63 MMBTU/hr Boiler SCR Retrofit - General Information Parameter Value Notes Heat Input (MMBtu/hr)63.0 Hours of operation (hr/yr)8760 Assume annual operation Current Emission Rate (tpy)2.59 Estimated Removal Efficiency 70%EPA Air Pollution control Technology Fact Sheet - SCR Estimated Emission Rate (tpy)0.78 Post SCR control Estimated Ammonia Usage (lb/hr)0.86 Calculated using U.S. EPA Cost Control Manual Section 4 Chapter 2 Selective Catalytic Reduction Costs equation 2.35 Cost of Ammonia Reagent ($/lb)0.27 Quote from Thatcher ($1.38/gallon for 19% ammonia) Cost of Catalyst ($/ft3)$227.00 U.S. Environmental Protection Agency (EPA). Documentation for EPA’s Power Sector Modeling Platform v6 Using the Integrated Planning Model. Office of Air and Radiation. May 2018. Available at: https://www.epa.gov/airmarkets/documentation-epas-power-sector-modeling-platform-v6 Operator ($/hour)$28.50 Utah Department of Workforce Services, Occupational Wages by Region, Median Annual Wage for Installation/Maintenance/Repair, Machinery cited $59,300. Assumed a standard working year contains 2,080 hours. Equipment Life Expectancy (Years)23 U.S. EPA Cost Control Manual Section 4 Chapter 2 Selective Catalytic Reduction Costs average life expectancy for industrial boilers Interest Rate (%)7.00%OMB Circular A-4, https://obamawhitehouse.archives.gov/omb/circulars_a004_a-4/ Table I-2. RACT Control Cost Evaluation for 63 MMBTU/hr Boiler SCR Retrofit - Capital Investment Parameter Value Notes Total Increase in Capital Investment ($)$538,807 Cost estimate based on communication with CECO Environmental December 2023 Direct Installation Costs $161,642 U.S. EPA's Alternative Control Techniques Document -- NOx Emissions from Industrial/Commercial/Institutional (ICI) Boilers, Section 6.1.1.2 Direct Installation Costs Indirect Installation Costs $177,806 U.S. EPA's Alternative Control Techniques Document -- NOx Emissions from Industrial/Commercial/Institutional (ICI) Boilers, Section 6.1.1.3 Indirect Installation Costs Contingency $134,702 This cost was added as the total equipment cost was obtained anonymously and a minimum equipment cost was provided. Freight $26,940 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Table 2.4 Sales Tax $16,164 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Table 2.4 Instrumentation $53,881 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Table 2.4 Capital Recovery Factor (CRF)0.0895 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Equation 2.8a Capital Recovery Cost (CRC)$99,382 U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Equation 2.8 Process Information Labor Costs Economic Factors US Magnesium LLC A-9 Trinity Consultants June 2024 Appendix A. Cost Analysis Table I-3. RACT Control Cost Evaluation for 63 MMBTU/hr Boiler SCR Retrofit - Annual Operating, Insurance, Tax, and Other Costs Parameter Value Notes Operating Labor $35,369 U.S. EPA Cost Control Manual Section 4 Chapter 2 Selective Catalytic Reduction Costs estimates 4 hours per day of Operating and Supervisory Labor. The estimate presented utilizes Section 1, Chapter 2's assumption tat 15% of operating labor is supervisory labor Supervisory Labor $6,242 Assumed to be 15% of operating Labor, U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Section 2.6.5.2 Maintenance Labor and Materials $2,694 U.S. EPA Cost Control Manual Section 4 Chapter 2 Selective Catalytic Reduction Costs estimates maintenance costs to be 0.5 percent of the total capital investment. Annual Reagent Costs $469 U.S. EPA Cost Control Manual Section 4 Chapter 2 Selective Catalytic Reduction Costs equation 2.58, assumed 2,000 hours of operation consistent with the reduced heat load Annual Catalyst Costs $4,903 Catalyst size calculated based on information provided in U.S. EPA's Air Pollution Control Technology Fact Sheet for SCR (EPA-452/F-03-032). Assumed Catalyst life of 5 years. Total Direct Operating Costs $49,677 Sum of Direct Operating Costs on an Annual Basis Overhead $26,582 Assumed to be 60% of there total Direct Operating Costs, U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Section 2.6.5.7 Property Tax $5,388 Assumed to be 1% of the Total Capital Investment, U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Section 2.6.5.8 Increase in Insurance $5,388 Assumed to be 1% of the Total Capital Investment, U.S. EPA Cost Control Manual Section 1, Chapter 2 Cost Estimation: Concepts and Methodology, Section 2.6.5.8 Administrative Charges $1,093 U.S. EPA Cost Control Manual Section 4, Chapter 2, Equation 2.69 Total Insurance, Tax, and Other Annual Costs $38,452 Sum of Insurance, Tax, and Other Annual Costs Table I-4. RACT Control Cost Evaluation for 63 MMBTU/hr Boiler SCR Retrofit - Total Annual Cost & Cost per Ton Removed Parameter Value Notes Total Annual Cost $187,510 Sum of Capital Recovery Cost, Total Direct Operating Costs, Insurance, Tax and Other Annual Costs. NOX Removed (tpy)1.81 Cost per Ton of NOX Removed $103,482 NOX Cost Per Ton Removed Direct Operating Costs Insurance, Tax, and Other Annual Costs US Magnesium LLC A-10 Trinity Consultants June 2024