Technical Support Document for Draft Air Emission Permit No

Transcription

1 Technical Support Document for Draft Air Emission Permit No This technical support document (TSD) is intended for all parties interested in the draft permit and to meet the requirements that have been set forth by the federal and state regulations (40 CFR 70.7(a)(5) and Minn. R , subp. 1). The purpose of this document is to provide the legal and factual justification for each applicable requirement or policy decision considered in the preliminary determination to issue the draft permit. 1. General information 1.1 Applicant and stationary source location Table 1. Applicant and source address Applicant/Address CHS Inc 5500 Cenex Dr Inver Grove Heights, Minnesota Contact: Stephanie McGrath Phone: Stationary source/address (SIC Code: Grain and Field Beans) CHS Inc - Prairie Lakes Coop - Glenwood Grain Elevator th Ave NE Glenwood, MN Facility description CHS Inc - Prairie Lakes Coop - Glenwood Grain Elevator ("CHS" or "the facility") is a country grain elevator limited to 720,000 tons of grain received per year. Three types of grain are received: corn, soybeans, and wheat. There are three truck receiving pits where grain is received by hopper truck or straight truck. One of the receiving pits is vented to a baghouse for particulate matter control. There is one rail receiving pit that is rarely used. The facility has 22 silo/bins for storage. Seven of the bins have bins vents. Grain may also be stored at four temporary storage piles. Pile 1 has an 8.4 foot tall concrete wall, and is fed through one of the truck receiving pits that routes grain to three outdoor conveyors in series. The other three piles have 4 or 6 feet tall walls. Grain may be added to these pile using two portable outdoor conveyors that receive grain directly from trucks. All piles are covered by tarps during storage. The piles are filled and emptied once each year, and the maximum amount of grain that is put into temporary storage is 135,000 tons each year. When grain is reclaimed from the piles, a portion of the tarp is torn away and a grain gobbler is used to suck up the grain, convey it upwards on an incline, and drop it into a truck. The truck then drives to one of the receiving pits to dump the grain for drying or storage in one of the silo/bins. If wet grain is received or reclaimed from one of the temporary storage areas, the grain may be dried in one of the two column dryers prior to storage or loadout. There are three truck loadout spouts and one rail loadout station. Grain is primarily loaded out to rail, with a small portion loaded out to truck. The facility has two 10,000 gallon diesel tanks that are used for truck fueling that are categorized as insignificant activities. Particulate matter (PM), particulate matter less than ten microns (PM10), and particulate matter less than 2.5 microns (PM2.5) are the main pollutants of concern at this facility. Sources of particulate matter include emissions from grain receiving, storage (silo vents), drying, handling, and loadout, and fugitive emissions from unpaved roads, truck traffic, the addition of grain to temporary storage piles, and reclaim of grain from the storage piles. A small amount of combustion-related pollutants are also emitted from drying, including nitrogen oxides (NOx), carbon monoxide (CO), carbon dioxide equivalents (CO2e), and hazardous air pollutants (HAPs). 1.3 Description of the activities allowed by this permit action This permit action is an individual State Permit. Technical Support Document, Permit Number: Page 1 of 13

2 1.4 Facility emissions Table 2. Total facility potential to emit summary PM PM10 PM2.5 SO2 NOx CO CO2e VOC Single HAP All HAPs Total facility limited potential emissions including fugitive sources , Total facility limited potential emissions not including fugitive sources , Total facility actual emissions (2017) * 0.15 * *Not reported in Minnesota emission inventory. Table 3. Facility classification Classification Major Synthetic minor/area Minor/Area New Source Review X Part 70 X Part 63 X 2. Regulatory and/or statutory basis 2.1 New source review (NSR) The Permittee has accepted limits on the facility such that it is a minor source under New Source Review regulations. Emissions of PM do exceed 250 tons per year when fugitives are included. However, the facility is not one of the source types listed in 40 CFR 52.21(b)(1)(iii), so fugitives emissions are not included when determining major source applicability. The fugitive sources that are not included in the total are the emissions from the temporary storage piles and the unpaved roads. When those emissions are excluded, the PM potential to emit is 176 tons per year. 2.2 Part 70 permit program The Permittee has accepted limits on the facility such that it is a nonmajor source under the Part 70 permit program. Although PM potential to emit is over 100, PM is not considered a regulated pollutant within the definition of a major source in 40 CFR According to the EPA guidance document dated October 16, 1995, with subject line Definition of Regulated Pollutant for Particulate Matter for Purpose of Title V, written by Lydia N. Wegman, Deputy Director, a Title V operating permit is not required if the only pollutant that would make the source major is particulate matter. 2.3 New source performance standards (NSPS) The Permittee has stated that no New Source Performance Standards apply to the operations at this facility. This facility is not subject to 40 CFR pt. 60, subp. DD Standards of Performance for Grain Handling Facilities. Applicability is based on a grain elevator s storage capacity, which must exceed 2.5 million bushels Technical Support Document, Permit Number: Page 2 of 13

3 for any grain storage facility not for human consumption. The storage capacity of grain elevators at this facility is 1,739,692 bushels; therefore, Subpart DD does not apply. 2.4 National emission standards for hazardous air pollutants (NESHAP) The facility is a minor source under NESHAP regulations. The Permittee has stated that no area source NESHAP standards apply. 2.9 Minnesota State Rules Portions of the facility are subject to the following Minnesota Standards of Performance: Minn. R Standards of Performance for Dry Bulk Agricultural Commodity Facilities Table 4. Regulatory overview of facility Subject item* Applicable regulations Rationale TFAC 1 (Air Quality Total Facility) TFAC 1 (Air Quality Total Facility) TFAC 1 (Air Quality Total Facility) COMG 2 (Enclosed Material Handling ) Title I Condition: Avoid major source under 40 CFR 52; To avoid major source under 40 CFR 70.2 Minn. R , subp. 2(B) Minn. R Minn. R Prevention of Significant Deterioration (PSD). Limits on total annual grain throughput and annual grain drying to reduce PM10 and PM2.5 emissions below major source thresholds under NSR and Part 70. Emission Limitations and Standards. Minnesota Permit Content rules dictate that the permit must include conditions as necessary to protect human health and the environment. The Permittee assumed 135,000 tons per year of temporary storage capacity in calculating their potential emissions. Excessive fugitive PM, PM10, and PM2.5 emissions from temporary storage and related activities can have a detrimental effect on human health and the environment, therefore, it is necessary to restrict the storage activities. Standards of Performance for Dry Bulk Agricultural Commodity Facilities (Bulk Ag Rule or BAR ). This rule applies to facilities that unload, handle, store, grind, or load dry bulk agricultural commodities, which includes corn, soybeans, and wheat. Any owner or operator of a commodity facility is subject to a requirement to clean up commodities on the driveway and facility property in order to minimize fugitive emissions. Standards of Performance for Dry Bulk Agricultural Commodity Facilities. This rule applies to facilities that unload, handle, store, grind, or load dry bulk agricultural commodities, which includes corn, soybeans, and wheat. Commodity facilities fall into the control required category of the rule if they have an annual commodity throughput of more than 180,000 tons. The Prairie Lakes facility has consistently had annual commodity throughputs well over this amount, and will have a maximum throughput of 720,000 tons per year upon issuance of permit # For control required facilities, a five percent opacity limit applies to emissions from any handling operation. The equipment in COMG 2 includes all fully enclosed conveyors and legs at the facility. The transfer and movement of grain is considered a handling operation, therefore the opacity limit applies. Technical Support Document, Permit Number: Page 3 of 13

4 Subject item* Applicable regulations Rationale COMG 3 (Unvented Silos) COMG 4 (Vented Bins) 5 (Receiving Pit 1) Minn. R Minn. R Minn. R Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. A five percent opacity limit applies to emissions from any handling operation. The equipment in COMG 3 includes all silos that do not have silo vents. The transfer of grain into and out of the silos is considered a handling operation, therefore the opacity limit applies. Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. A five percent opacity limit applies to emissions from any handling operation, including transfer of grain into or out of vented bins. Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. A five percent opacity limit applies to emissions from truck unloading stations and Receiving Pit 1 is a truck unloading station. 7 (GSI Dryer) Minn. R Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. The BAR contains specifications for perforation size that apply to column dryers and the GSI Dryer is a column dryer. 8 (Zimmerman Dryer) 10 (Receiving Pit 2) 11 (Receiving Pit 3) 39 (South Pile Conveyor) 59 (Rail Loadout) 60, 61, and 62 (Truck Loadout 1, 2, and 3) Minn. R Minn. R Minn. R Minn. R Minn. R Minn. R Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. The BAR contains specifications for perforation size that apply to column dryers and the Zimmerman Dryer is a column dryer. Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. A five percent opacity limit applies to emissions from truck unloading stations and Receiving Pit 2 is a truck unloading station. Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. A five percent opacity limit applies to emissions from truck unloading stations and Receiving Pit 3 is a truck unloading station. Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. A five percent opacity limit applies to emissions from any handling operation, including transfer of grain by conveyors. This conveyor feed storage Pile 1 (FUGI 1). Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. A five percent opacity limit applies to emissions from rail loading stations. Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. A ten percent opacity limit applies to emissions from truck loading stations. Technical Support Document, Permit Number: Page 4 of 13

5 Subject item* Applicable regulations Rationale 63 (Grain Gobbler) Minn. R Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. A five percent opacity limit applies to emissions from any handling operation, and a ten percent opacity limit applies to emissions from truck loading. Both limits apply to different portions of the grain gobbler. Handling occurs as the grain gobbler augers up grain from the pile and conveys it upward, and truck loading occurs when the grain is dropped out from the gobbler and into the truck. 64 (Rail Pit) Minn. R Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. A five percent opacity limit applies to emissions from rail unloading stations. 65 (Portable Conveyor 1 - Pile 2&3) 66 (Portable Auger/Conveyor 2 - Pile 4 FUGI 1 (Pile 1 (XT2)) FUGI 1 (Pile 1 (XT2)) Minn. R Minn. R Minn. R Minn. R , subp. 2(B) Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. A five percent opacity limit applies to emissions from truck loadout and handling operations. Truck loadout occurs when the grain is transferred from the truck to the portable conveyor, and handling occurs as the grain is transferred up the conveyor and dropped onto the pile. Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. A five percent opacity limit applies to emissions from truck loadout and handling operations. Truck loadout occurs when the grain is transferred from the truck to the portable conveyor, and handling occurs as the grain is transferred up the conveyor and dropped onto the pile. Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. A five percent opacity limit applies to emissions from any handling operation, including adding grain to the pile or removing grain from the pile. Emission Limitations and Standards. Minnesota Permit Content rules dictate that the permit must include conditions as necessary to protect human health and the environment. The Permittee assumed 30,000 tons of storage capacity for Pile 1. The capacity of Pile 1, and the assumption that it is only filled and emptied once per year, factors into the calculations of potential emissions from receiving, handling (headhouse calculation), and emissions from silo vents since the grain added to Pile 1 must go through the main receiving and transfer process twice. This is because grain is added to Pile 1 through conveyors that are connected to one of the receiving pits, and when the grain is reclaimed it is received again. The Permittee also stated, and assumed in the calculations, that the pile would be fully covered while grain is being stored. Excessive fugitive PM, PM10, and PM2.5 emissions from temporary storage and related activities can have a detrimental effect on human health and the environment, therefore, it is necessary to limit the storage activities. Technical Support Document, Permit Number: Page 5 of 13

6 Subject item* Applicable regulations Rationale FUGI 2 (Unpaved Roads) FUGI 2 (Unpaved Roads) FUGI 2 (Unpaved Roads) FUGI 3, 4, and 5 (Piles 2, 3, and 4) FUGI 3, 4, and 5 (Piles 2, 3, and 4) TREA 1 (Pit 2 Baghouse) TREA 1 (Pit 2 Baghouse) Minn. R Minn. R , subp. 2(A) and (B) Minn. R , subp. 2(B) Minn. R Minn. R , subp. 2(B) Minn. R Minn. R , subp. 2(A) *Location of the requirement in the permit (e.g., 1, STRU 2, etc.). 3. Technical information Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. A requirement to clean up commodities spilled on the driveway or other facility property as required to minimize fugitive emissions to a level consistent with RACT (reasonably available control technology) applies to the roadways at the facility. Emission Limitations and Standards. Minnesota Permit Content rules dictate that the permit must include emission limitations, operational requirements, and other provisions needed to ensure compliance with all applicable requirements, and must include conditions as necessary to protect human health and the environment. The requirement to clean roadways whenever fugitive emissions are observed (and on a monthly basis, at a minimum) is necessary to comply with the BAR applicable requirement to minimize fugitive emissions from spilled commodities and with Minn. R requirement (see TFAC) to prevent particulate matter from becoming airborne. Other corrective actions may be necessary to protect human health and the environment from fugitive dust emissions from the unpaved roads. Emission Limitations and Standards. Minnesota Permit Content rules dictate that the permit must include conditions as necessary to protect human health and the environment. Limiting vehicle speed on unpaved roads greatly reduces that amount of fugitive dust generated. Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. A five percent opacity limit applies to emissions from any handling operation, including adding grain to the pile or removing grain from the pile. Emission Limitations and Standards. Minnesota Permit Content rules dictate that the permit must include conditions as necessary to protect human health and the environment. The Permittee has stated, and assumed in the calculations, that the pile would be fully covered while grain is being stored. Excessive fugitive PM, PM10, and PM2.5 emissions from temporary storage of grain can have a detrimental effect on human health and the environment, therefore, it is necessary to cover the pile whenever possible. Standards of Performance for Dry Bulk Agricultural Commodity Facilities. See COMG 2 for explanation of rule applicability. Several requirements from the BAR apply to control equipment at control required facilities. Emission Limitations and Standards. Minnesota Permit Content rules dictate that the permit must include emission limitations, operational requirements, and other provisions needed to ensure compliance with all applicable requirements. More specific permit conditions for the operation and maintenance of the control are needed to ensure compliance with the applicable requirements from the BAR. Technical Support Document, Permit Number: Page 6 of 13

7 3.1 Calculations of potential to emit (PTE) Attachment 1 to this TSD contains the PTE summary for the Facility, and detailed spreadsheets and supporting information prepared by the MPCA and the Permittee. 3.2 Bulk Agricultural Rule Requirements Due to compliance concerns at other grain handling facilities that are subject to the BAR, daily visible emissions checks (and corrective actions if visible emissions are seen) are required at many of the emission units that are subject to an opacity limit from the rule. This includes each receiving pit, silo vent, unloading station, outdoor conveyor, and the grain gobbler. From the BAR, opacity limits apply to fugitive emissions from loading and unloading stations, and from handling operations. Although opacity limits do not explicitly apply at silo vents, the transfer of grain into and out of the silo is considered a handling operation, and the point that emissions may occur is at the silo vent. Similarly, opacity limits apply to the outdoor conveyors and to the grain gobbler because these are grain handling activities. The exceptions where no visible emissions checks were put in the permit are at the fully enclosed conveyors and legs (COMG 2), the silos without vents (COMG 3), and the storage piles (FUGI 1, 3, 4, and 5). Opacity limits apply to the enclosed conveyors, legs, and unvented silos, but no emissions are expected to occur. Opacity limits apply to the temporary storage piles as well, but only while handling occurs, so the visible emissions checks were placed at the emissions units that are used to add or remove grain to the pile, and not to the piles themselves. With the exception of truck loading (which has a 10 percent opacity limit) a 5 percent opacity limit applies to the activities where monitoring is required. 5 percent opacity is very low. Essentially, if the emissions are visible then they are exceeding the limit, therefore Method 22 for Visual Determination of Fugitive Emissions is appropriate. If visible emissions are observed, the Permittee must take corrective actions. Several possible corrective actions are listed at each subject item, but the Permittee may employ other corrective actions as needed. 3.3 Monitoring In accordance with the Clean Air Act, it is the responsibility of the owner or operator of a facility to have sufficient knowledge of the facility to certify that the facility is in compliance with all applicable requirements. In evaluating the monitoring included in the permit, the MPCA considered the following: the likelihood of the facility violating the applicable requirements; whether add-on controls are necessary to meet the emission limits; the variability of emissions over time; the type of monitoring, process, maintenance, or control equipment data already available for the emission unit; the technical and economic feasibility of possible periodic monitoring methods; and the kind of monitoring found on similar units elsewhere. Table 5 summarizes the monitoring requirements. Table 5. Monitoring Subject Item* Requirement (basis) What is the monitoring? Why is this monitoring adequate? Technical Support Document, Permit Number: Page 7 of 13

8 Subject Item* Requirement (basis) What is the monitoring? Why is this monitoring adequate? TFAC 1 (Air Quality Total Facility) TFAC 1 (Air Quality Total Facility) The Permittee shall limit Process Throughput <= 720,000 tons per year 12-month rolling sum of grain received. [Title I Condition: Avoid major source under 40 CFR 52.21(b)(1)(i) and Minn. R , To avoid major source under 40 CFR 70.2 & Minn. R ] The Permittee shall limit Process Throughput <= 400,000 tons per year 12-month rolling sum of grain dried. [Title I Condition: Avoid major source under 40 CFR 52.21(b)(1)(i) and Minn. R , To avoid major source under 40 CFR 70.2 & Minn. R ] Daily recordkeeping, monthly totals, month calculation of 12- month sum. Daily recordkeeping, monthly totals, month calculation of 12- month sum. The Permittee will maintain daily records of the amount of grain received in any receiving pit, unless it is grain that was reclaimed from Pile 1. The grain from Pile 1 is accounted for when it is added to the pile through one of the receiving pits, so counting it again when it is reclaimed from the pile would double count. Grain amounts are automatically recorded in the computer system that is hooked up to the Permittee s scale system. These daily records can be used to calculate the total amount of grain received each month, and the monthly totals can be used to calculate the 12-month rolling sum. The Permittee will maintain daily records of the amount of grain dried. Drying amounts are automatically recorded in the facility s computer system. These daily records can be used to calculate the total amount of grain dried each month, and the monthly totals can be used to calculate the 12-month rolling sum. TFAC 1 (Air Quality Total Facility) The Permittee shall limit Process Throughput <= tons per year 12-month rolling sum of grain stored in the temporary storage piles [Minn. R , subp. 2(B)] Daily recordkeeping, monthly totals, month calculation of 12- month sum. The Permittee will maintain daily records of the amount of grain added to any storage pile. Grain amounts and where the grain was delivered is automatically recorded in the computer system that is hooked up to the scales. These daily records can be used to calculate the total amount delivered to any pile in each month, and the monthly totals can be used to calculate the 12- month rolling sum. Technical Support Document, Permit Number: Page 8 of 13

9 Subject Item* COMG 2 (Enclosed Material Handling ) COMG 3 (Unvented Silos) COMG 4 (Vented Bins) 5 (Receiving Pit 1), 10 (Receiving Pit 2), and 11 (Receiving Pit 3) Requirement (basis) Opacity <= 5 percent opacity from handling operation fugitive emissions. [Minn. R , subp. 3(A)] Opacity <= 5 percent opacity from handling operation fugitive emissions. [Minn. R , subp. 3(A)] Opacity <= 5 percent opacity from any bin vent while transferring grain into or out of the bin. [Minn. R , subp. 3(A)] Opacity <= 5 percent opacity from truck unloading station fugitive (uncaptured) emissions. [Minn. R , subp. 3(A)] What is the monitoring? None None Daily Visible Emissions (VE) checks Daily Visible Emissions (VE) checks Why is this monitoring adequate? This component group (COMG) consists only of fully enclosed conveyors and legs that are used to transport grain. No pressure release valves or fans are used in the grain handling system. Pressure that is created from the movement of grain through an individual conveyor or leg is taken in by other connected conveyors and legs. These enclosed emission units are designed to lose as little material as possible, therefore, very little, if any, opacity is expected to be emitted from them and no monitoring is needed. This COMG includes only concrete bins that do not have bin vents. No pressure relief valves, vents, or fans are used to relieve pressure as grain is added or removed from the vents. Pressure changes are relieved through the connected conveyors and legs. The concrete bins can also expand and withstand pressure better than steel bins, and are not filled as high so that the pressure does not get too high. Very little, if any, opacity is expected from the enclosed bins, therefore no monitoring is needed. The Permittee will use Method 22 to check for visible emissions from bin vents once each day of operation while grain is being added to one or more bins. The Permittee will conduct the check on all bins vents from a location at the facility where all the vents are viewable. The opacity limit applies while grain is being added to the bin or removed from the bin, but the worst case scenario occurs while grain is being added to the bin and air is being forced out of the bin through the bin vents. Since the grain dust is mostly contained by the bin, it is less likely that the opacity limit will be exceeded, so a group VE check is appropriate. If visible emissions are seen, then it is likely that the limitation is being exceeded, and the Permittee must take corrective actions. The Permittee will use Method 22 to check for visible emissions from each grain receiving pit once each day of operation. Since the opacity limitation for this type of operation is low (5 percent opacity) VE checks are appropriate to determine compliance. If visible emissions are seen, then it is likely that the limitation is being exceeded, and the Permittee must take corrective actions. Technical Support Document, Permit Number: Page 9 of 13

10 Subject Item* 39 (South Pile Conveyor) 59 (Rail Loadout) 60, 61, and 62 (Truck Loadout 1, 2, and 3) 63 (Grain Gobbler) Requirement (basis) Opacity <= 5 percent opacity from handling operation emissions. [Minn. R , subp. 3(A)] Opacity <= 5 percent opacity from railcar loading station fugitive (uncaptured) emissions. [Minn. R , subp. 3(A)] Opacity <= 10 percent opacity from truck loading station fugitive emissions. [Minn. R , subp. 3(B)] Opacity <= 5 percent opacity from handling operation fugitive emissions (this includes grain reclaim from the pile and conveyance up to the gobbler spout). [Minn. R , subp. 3(A)] What is the monitoring? Daily Visible Emissions (VE) checks Daily Visible Emissions (VE) checks Daily Visible Emissions (VE) checks Daily Visible Emissions (VE) checks Why is this monitoring adequate? The Permittee will use Method 22 to check for visible emissions from the pile conveyors once each day of operation. Since the opacity limitation for this type of operation is so low (5 percent opacity) VE checks are appropriate to determine compliance. Emissions are not expected from the movement of the grain on the conveyors themselves, since the conveyors are enclosed, but opacity may be seen at the drop point from the conveyor to the pile. If visible emissions are seen, then it is likely that the limitation is being exceeded, and the Permittee must take corrective actions. The Permittee will use Method 22 to check for visible emissions from rail loadout once each day of operation. Since the opacity limitation for this type of operation is so low (5 percent opacity) VE checks are appropriate to determine compliance. If visible emissions are seen, then it is likely that the limitation is being exceeded, and the Permittee must take corrective actions. The Permittee will use Method 22 to check for visible emissions from truck loadout once each day of operation. Even though the emission limit is slightly higher than most at 10 percent opacity instead of 5 percent, the presence of visible emissions is still a good indicator that the emission limit is being exceeded. If visible emissions are seen the Permittee must take corrective actions. The Permittee will use Method 22 to check for visible emissions from handling operations once each day of operation. Handling operations include the reclaim of grain from the pile and the conveyance of the grain on the gobbler conveyer. Since the opacity limitation for this type of operation is low (5 percent opacity) VE checks are appropriate to determine compliance. If visible emissions are seen, then it is likely that the limitation is being exceeded, and the Permittee must take corrective actions. Technical Support Document, Permit Number: Page 10 of 13

11 Subject Item* 63 (Grain Gobbler) Requirement (basis) Opacity <= 10 percent opacity from truck loading fugitive emissions (this included emissions from the spout and the drop into the truck). [Minn. R , subp. 3(B)] 64 (Rail Pit) Opacity <= 5 percent opacity from railcar loading station fugitive (uncaptured) emissions. [Minn. R , subp. 3(A)] 65 (Portable Conveyor 1 - Pile 2&3) and 66 (Portable Auger/Conveyor 2 - Pile 4) FUGI 1 (Pile 1 (XT2)), FUGI 3 (Pile 2 (XT7)), FUGI 4 (Pile 3 (XT8)), and FUGI 5 (Pile 4 (XT5)) TREA 1 (Pit 2 Baghouse) Opacity <= 5 percent opacity from truck unloading and handling operation emissions. [Minn. R , subp. 3(A)] Opacity <= 5 percent opacity from handling operation fugitive emissions. [Minn. R , subp. 3(A)] Particulate Matter >= 80 percent collection efficiency for the control equipment. [Minn. R , subp. 3(E)] What is the monitoring? Daily Visible Emissions (VE) checks Daily Visible Emissions (VE) checks Daily Visible Emissions (VE) checks None See monitoring for compliance with 99% control efficiency for PM. Why is this monitoring adequate? The Permittee will use Method 22 to check for visible emissions from the addition of grain from the gobbler conveyor into a truck once each day of operation. Even though the emission limit is slightly higher than most at 10 percent opacity instead of 5 percent, the presence of visible emissions is still a good indicator that the emission limit is being exceeded. If visible emissions are seen the Permittee must take corrective actions. The Permittee will use Method 22 to check for visible emissions from each grain receiving pit once each day of operation. Since the opacity limitation for this type of operation is so low (5 percent opacity) VE checks are appropriate to determine compliance. If visible emissions are seen, then it is likely that the limitation is being exceeded, and the Permittee must take corrective actions. The Permittee will use Method 22 to check for visible emissions from each portable conveyor once each day of operation. Emissions may be generated from unloading of the grain from trucks to the conveyor, from the grain being conveyed, and from the drop of the grain onto the pile. Since the opacity limitation for this type of operation is so low (5 percent opacity) VE checks are appropriate to determine compliance. If visible emissions are seen, then it is likely that the limitation is being exceeded, and the Permittee must take corrective actions. The opacity limit applies when grain is being added to or removed from a pile, and does not apply while the grain is being stored. Since the emission units that add or remove grain already have daily visible emissions checks, there is no need to have visible emissions checks on the piles themselves. Baghouse filters typically achieve control or collection efficiencies well above 80%. The monitoring required to comply with the 99% control efficiency limit for PM is adequate to ensure compliance with this limit. Technical Support Document, Permit Number: Page 11 of 13

12 Subject Item* TREA 1 (Pit 2 Baghouse) TREA 1 (Pit 2 Baghouse) TREA 1 (Pit 2 Baghouse) TREA 1 (Pit 2 Baghouse) Requirement (basis) Opacity <= 10 percent opacity discharged from control equipment. [Minn. R , subp. 3(D)] Particulate Matter >= 80 percent capture efficiency; PM10 >= 80 percent capture efficiency, PM2.5 >= 80 percent capture efficiency. [Minn. R , supb. 2(A)] Particulate Matter >= 99 percent control efficiency; PM < 10 micron >= 93 percent control efficiency; and PM < 2.5 micron >= 93 percent control efficiency. [Minn. R , supb. 2(A)] Pressure Drop >= 0.2 and <= 8.0 inches of water column. [Minn. R , supb. 2(A)] What is the monitoring? See monitoring for compliance with 99% control efficiency for PM. Annual Hood Evaluation Daily visible emissions checks or pressure drop reading during inclement weather; quarterly inspections; corrective actions; and operation according to the operation and maintenance plan Pressure drop monitoring; daily verification; annual calibration *Location of the requirement in the permit (e.g., 1, STRU 2, etc.). Why is this monitoring adequate? As long as the baghouse is properly operated and maintained, it is highly unlikely that this emission limit would be exceeded. The monitoring required to comply with the 99% control efficiency limit for PM is adequate to ensure compliance with this limit. The hood is required to be certified by a testing company to ensure that 80% capture efficiency can be achieved. This is required to be done within 30 days after permit issuance. Once the certification is complete, the Permittee must conduct an annual evaluation that measures the fan rotation speed, power draw, face velocity or other indicator of performance that was measured in the hood certification in order to verify that the hood continues to conform to the specifications of the hood certification and continues to achieve 80% capture. The control efficiencies assumed should be easily achievable by a properly operated and maintained baghouse. Daily visible emissions checks or pressure drop monitoring (during inclement weather), ensure that the equipment continues to operate at the expected level of control. Periodic inspections alert the Permittee to any maintenance issues. The monitor is required to be installed, in use, and properly maintained at all times that the control equipment is operating. There is a requirement at the total facility level (TFAC 2) that applies to any monitor at the facility, that states that the monitor must be calibrated or replaced every 12 months, or at the frequency stated in manufacturer s specifications. This will ensure that the monitor continues to read accurately. 3.4 Insignificant activities CHS Inc - Prairie Lakes Coop - Glenwood Grain Elevator has several operations which are classified as insignificant activities under the MPCA s permitting rules. These are listed in Appendix A to the permit. The permit is required to include periodic monitoring for all emissions units, including insignificant activities, per EPA guidance. The insignificant activities at this Facility are only subject to general applicable requirements. Using the criteria outlined earlier in this TSD, the following table documents the justification Technical Support Document, Permit Number: Page 12 of 13

13 why no additional periodic monitoring is necessary for the current insignificant activities. See Attachment 1 of this TSD for PTE information for the insignificant activities. Table 6. Insignificant activities Insignificant activity Individual units with potential emissions less than 2000 lb/year of certain pollutants General applicable emission limit PM, variable depending on airflow Opacity <= 20% (Minn. R ) Discussion The only potential emissions from the two 10,000 gallon diesel tanks are from VOCs and HAPs, therefore, it is highly unlikely that these units would exceed the PM or opacity standards. 3.5 Permit organization The only item that deviates from MPCA Tempo Guidance is the listing of certain applicable requirements at the group level even though they apply at the individual unit. Specifically, the opacity limitation that applies to handling operations from the Standards of Performance for Dry Bulk Agricultural Commodity Facilities is listed at COMG 2 (Enclosed Material Handling ) and COMG 3 (Unvented Silos). In general, limits that apply to individual pieces of equipment should be tracked at the unit level and should not be listed at a group. The main reason is if there were noncompliance with a limit by one unit within the group, the computer system would say the whole group was out of compliance. For this case, the enclosed conveyors and legs un unvented silos are not reasonably expected to generate opacity, much less violate the limits. Therefore, it is highly unlikely that the MPCA would need to track noncompliance with this limit at the individual unit level so a group is an acceptable way to include these requirements. 3.6 Comments received Public Notice Period: [start date] [end date] EPA Review Period: [start date] [end date] 4. Permit fee assessment This permit action is the issuance of an individual State Permit based on an application received 8/17/2018. Even though the Permittee previously held a registration permit, this action is not considered a reissuance of an individual state operating permit; therefore, the application fees apply under Minn. R Attachment 3 to this TSD contains the MPCA s assessment of Application and Additional Points used to determine the permit application fee for this permit action as required by Minn. R Conclusion Based on the information provided by CHS Inc - Prairie Lakes Coop - Glenwood Grain Elevator the MPCA has reasonable assurance that the proposed operation of the emission facility, as described in the Air Emission Permit No and this TSD, will not cause or contribute to a violation of applicable federal regulations and Minnesota Rules. Staff members on permit team: Rachel Yucuis (permit engineer) Peggy Bartz (peer reviewer) Beckie Olson (permit writing assistant) Laurie O'Brien (administrative support) TEMPO360 Activities: State Permit (IND ) Attachments: 1. PTE summary and calculation spreadsheets 2. Subject item inventory and facility requirements 3. Points Calculator Technical Support Document, Permit Number: Page 13 of 13

14 Attachment 1: PTE summary and calculation spreadsheets CHS Inc Prairie Lakes Coop Glenwood Grain Elevator Permit Number:

15 Unrestricted Emissions () # Description PM PM 10 PM 2.5 NOx CO SO 2 VOC N 2 O CH 4 CO 2 CO 2 e HAPs Total HAPs Single 5 Receiving Pit Receiving Pit Receiving Pit Bin Bin Bin Bin Bin Bin Bin GSI Dryer Zimmerman Dryer Rail Loadout Truck Loadout Truck Loadout Truck Loadout Rail Pit COMG 2 Enclosed Material Handling FUGI 1 Pile 1 (XT2) FUGI 2 Unpaved Roads FUGI 3 Pile 2 (XT7) FUGI 4 Pile 3 (XT8) FUGI 5 Pile 4 (XT5) Totals with fugitives Totals without fugitives

16 Limited Emissions () # Description PM PM 10 PM 2.5 NOx CO SO 2 VOC N 2 O CH 4 CO 2 CO 2 e HAPs Total HAPs Single 5 Receiving Pit * Receiving Pit 2 11 Receiving Pit Bin Bin Bin Bin Bin Bin Bin GSI Dryer Zimmerman Dryer ** Rail Loadout 60 Truck Loadout Truck Loadout Truck Loadout * Rail Pit COMG 2 Enclosed Material Handling FUGI 1*** Pile 1 (XT2) FUGI 2 Unpaved Roads FUGI 3 Pile 2 (XT7) FUGI 4 Pile 3 (XT8) FUGI 5 Pile 4 (XT5) Totals with fugitives Totals without fugitives *Grain can be received at any pit, so worst case limited emissions occur when grain is received at the truck pits the are not controlled by the baghouse ( 5 and 11) **Worst case loadout is by truck, so limited emissions from loadout are accounted for at the truck loadout stations (60, 61, and 62) ***Pile 1 is excluded from the limited emissions from because it does not include emissions from the transfer of grain from a truck to a pile conveyor, since Pile 1 is fed by enclosed permanent conveyors that receive grain from a pit. Limited emissions are applied at the other three piles (FUGI 3, 4, and 5)

17 Actual Grain Received Year Bushels Tons ,000, ,000 Conversions lb/bushel lb/ft^ ,958, ,763 Corn ,750, ,500 Soybeans ,983, ,497 Wheat ,764, ,927 Conservatively assume 60 lb/bushel for all grain. Permit Limits Total Throughput 720,000 tons/year Dryer Throughput 400,000 tons/year Temporary Storage Capacity 135,000 tons/year Other Limiting factors: Pile #1 Capacity 30,000 tons/year The amount is not a permit limit because this is the actual capacity of the pile

18 CHS Inc Prairie Lake Coop, Glenwood Grain Elevator Permit # Grain Receiving Receiving Pits Limiting factor design capacity units design capacity units Receiving Pit 1 ( 5) and Rail Pit ( 64) Leg 1 ( 13) bushels/hr 300 tons/hr Receiving Pit 2 ( 10) Pit 2 Leg ( 16) bushels/hr 750 tons/hr Receiving Pit 3 ( 11) Pit 3 Leg ( 17) bushels/hr 750 tons/hr Notes: Leg capacity is used to determine the hourly receiving rate for each receiving pit, since Leg capacity is the limiting factor (has a throughput capacity less than the receiving conveyor). Receiving Pit 1 and Rail Pit both flow to Leg 1. Emission factors are from AP 42 Table Grain is received from straight trucks and hopper trucks. Worst case hourly emissions scenario assumes all straight truck. Emissions are vented to a baghouse (TREA 1) at Pit 2 ( 10). Pit 1 ( 5) and Pit 3 ( 11) do not vent to the baghouse. Limited annual emissions assume 720,000 tons/year (permit limit) and that all grain is received by straight truck at one of the truck pits without control (worst case scenario). Limited emissions also include potential emissions from hopper trucks that are used to reclaim grain from temporary storage Pile #1 (FUGI 1). Storage Pile #1 is fed by conveyors that are connected to the main grain handling system, so grain that is stored at Pile #1 may be received twice (once when added to the pile and once when reclaimed from the pile). Reclaim always utilizes straight trucks, the pile may be filled only once per year, and the capacity of PIle 1 is 30,000 tons. Receiving Pit 1 ( 5) Pollutant Receiving Pit 2 ( 10) Emission Factor Emissions Control Efficiency lb/ton lb/hr PM % PM % PM % Pollutant Emission Factor lb/ton Control Efficiency Uncontrolled Emissions lb/hr Unlimited/Uncontrolled Emissions Controlled Emissions lb/hr Unlimited/Uncontrolled Emissions PM % PM % PM %

19 Receiving Pit 3 ( 11) Pollutant Rail Pit ( 64) Emission Factor Emissions Control Efficiency lb/ton lb/hr PM % PM % PM % Unlimited/Uncontrolled Emissions Pollutant Emission Factor Emissions Unlimited/Uncontrolled Emissions Control Efficiency lb/ton lb/hr PM % PM % PM % Limited Annual Emissions (Applied to uncontrolled truck receiving pits 5 and 11) Description Pollutant Throughput Rate Emission Factor tons/yr lb/ton Control Efficiency Limited Annual emissions Straight Trucks PM 720, % Straight Trucks PM , % Straight Trucks PM , % 3.60 Hopper Trucks PM 30, % 0.53 Hopper Trucks PM 10 30, % 0.12 Hopper Trucks PM , % 0.02 Total Annual Emissions from all receiving PM PM PM Limited emissions per uncontrolled receiving station (total/2) PM PM PM

20 CHS Inc Prairie Lake Coop, Glenwood Grain Elevator Permit # Grain Drying Criteria Pollutant Emissions GSI Dryer ( 7) Zimmerman Dryer ( 8) short term capacity 4000 bushels/hr 7000 bushels/hr 39.4 bushel/ton 39.4 bushel/ton tons/hr tons/hr limited capacity (applies to both dryers) 400,000 tons/year Fuel Natural gas fired Propane fired Heat input MMBtu/hr 72.9 MMBtu/hr 1020 Btu/scf 91.5 MMbtu/10^3 gallon ^6 scf/hr ^3 gallons/hr ^6 scf/year ^3 gallons/year Overall emissions from the dryer are from the grain itself plus the emissions from fuel combustion. Emission factors below are from AP 42 Table for grain drying with a column dryer Description # Pollutant Throughput Rate tons/hr Emission Factor lb/ton Emissions lb/hr GSI Dryer 7 PM GSI Dryer 7 PM GSI Dryer 7 PM Zimmerman Dryer 8 PM Zimmerman Dryer 8 PM Zimmerman Dryer 8 PM Pollutant Throughput Rate tons/yr Emission Factor lb/ton Limited Emissions PM 400, PM , PM , Limited emissions are based on the annual grain throughput limit. Since the emission factors for emissions from the grain are the same, the limited emissions from grain handling are not dependent on which dryer is used.

21 GSI Dryer Combustion Emissions (Natural Gas) Pollutant Emission Factor lb/10^6 scf Emission Factor Source Emissions lb/hr Unlimited Emissions Limited Emissions PM Totals from grain drying and fuel combustion Pollutant Emissions lb/hr Unlimited Emissions Limited Emissions NOx 100 AP 42 Table (Small Boilers, uncontrolled) PM CO 84 AP 42 Table (Small Boilers, uncontrolled) PM PM 7.6 AP 42 Table (Total)* PM PM AP 42 Table (Total)* PM AP 42 Table (Total)* SO AP 42 Table 1.4 2** VOC 5.5 AP 42 Table N 2 O 2.2 AP 42 Table (Uncontrolled) CH AP 42 Table CO AP 42 Table CO 2 e NA 40 CFR Part 98, Table A *All PM is assumed to be less than 1.0 micrometer in diameter, therefore PM=PM10=PM2.5. **Assumes that the sulfur content of natural gas is 2,000 grains/10^6 scf and that all fuel sulfur is emitted as SO 2 Zimmerman Dryer Combustion Emissions (Propane) Pollutant Emission Factor lb/10^3 gallons Emission Factor Source Emissions lb/hr Unlimited Emissions Limited Emissions PM Totals from grain drying and fuel combustion Pollutant Emissions lb/hr Unlimited Emissions Limited Emissions NOx 13 AP 42 Table PM CO 7.5 AP 42 Table PM PM 0.70 AP 42 Table PM PM AP 42 Table PM AP 42 Table SO AP 42 Table (SO 2 content 0.54 gr/100 ft^3) VOC 1.0 AP 42 Table N 2 O 0.9 AP 42 Table Note: Limited PM emissions from drying were calculated from the PM emissions from compusgion plus 50% of the PM emissions from the grain (50% of the annual capacity applied to each dryer). CH AP 42 Table CO AP 42 Table CO 2 e NA 40 CFR Part 98, Table A Global warming potentials of 1 for CO 2, 25 for methane, and 298 for nitrous oxide.