UNITED STATES ENVIRONMENTAL PROTECTION AGENO INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY. ' RESEARCH TRIANGLE PARK "< PRO^ NORTH CAROLINA' 277T1 DATE: June 19, 1978 SUBJECT: Controls for Industrial Fugitive Process PM Emissions FROM: J. H. Abbott, Chief Particulate Technology Branch,' IERL/RTP (MD-61 ) TO: J. B. Weigold Strategies and Air Standards Division (MD-12) In response to your memo of June 6, 1978, attached is a paper prepared on the state of control technology for industrial fugitive process partlculate matter (PM) emissions. The paper concludes that for nonferrous and two-thirds of iron and steel sources, fugitive .emissions are primarily less than 15. ym and therefore application of a respirable ambient standard to this size range would have the same effect as a JSP standard. However, for iron and steel sintering and open sources, the very large percentage of greater than 15 ym particles implies that even control technology which is slightly more effective for larger particles would have to be used to a much higher overall efficiency and cost to meet a TSP standard as opposed to a standard applied only to less than 15 ym particles. In general, control technology for fugitive particles is not highly efficient except at high cost. Lower levels of allowable emissions would result in higher costs for either total control or control of particles less than 15 .ym in diameter. We hope that this paper will provide you with the information you need. Because of the short deadline you requested for this information we do not think that this is the most thorough compilation of data possible. If you need additional assistance in this area, please do not hesitate to call upon us again. CC: J. Bachman W. Barber J. BuYchard J. Padgett E. Plyler F. Princiotta ------- POSITION PAPER STATE OF CONTROL TECHNOLOGY FOR INDUSTRIAL FUGITIVE PROCESS.PARTICIPATE -EMISSIONS Dr. D. C. Drehmel Industrial Environmental Research Laboratory U.S. Environmental Protection Agency Research Triangle Park, N.C. 27711 David P. Daugherty Charles H. Gooding Energy and Environmental Research Division Research Triangle Institute Research Triangle Park, N.C. 27709 ------- I. SUMMARY Fugitive particulates from industrial sources can be described by the mag- nitude and particle size distribution of the emission from source activities. Table 1 gives data for fugitive process emissions from integrated iron and steel plants. Uncontrolled fugitive emission rates are highest for electric arc furnaces and sintering machines. With the 'application of control, the greatest respirable* fugitive emissions are from coke ovens and electric arc furnaces. For comparison, stack emissions with control are also shown for respirable particles. Although sintering machine stack emissions are greater than any fugitive source, the total emissions from fugitive process sources are greater than the total emissions from stack sources. Table 2 gives data for fugitive open source emissions from integrated iron and steel plants. By far, the two t , sources with the greatest respirable fugitive emissions are vehicular traffic and storage pile activities. For a complete accounting of iron and steel fugitive sources, Table 3 gives both process and open sources in rank order according to total emissions for all particle sizes, not just respirable particles. In the table, the first six sources account for 95 percent of the overall emissions. These first six include coke ovens, three process sources, and two open sources. Coke oven emissions are primarily in the respirable size range. Process emissions from the two most important sources are not only primarily less than . 15 ym but also primarily less than 5 ym and hence could be described as fine , particles. Open source emissions are generally greater than 15 ym except for vehicular traffic on paved roads. Tables 4 and 5 give data on fugitive process emissions from lead and copper smelting. Highest rates for fugitive emissions in lead smelters come from sintering and concentrate storage and transfer. For these sources, as well as all others, the emissions are primarily in the respirable size range. Highest rates for fugitive emissions in copper smelters come from unloading of concentrate, roaster charging, and converter charging and tapping. For these sources and most copper smelter operations, the emissions are primarily less than 15 ym. However, for blister furnace charging and tapping, most particles are larger than 15 ym. *Respirable particles are assumed to be those with diameters less than 15 ym. ------- TABLE 1. FUGITIVE PROCESS EMISSIONS FROM INTEGRATED IRON AND STEEL PLANTS Process Estimated uncontrolled fugitive emission rates lb/ton process product Percent of Mass less than 15 urn Estimated controlled emissions in 1976 - nationwide mass in tons less than 15 ym Coke Ovens Charging Pushing Quenching Sintering Machine Hot Metal Transfer Electric Arc Furnace Alloy steel Carbon steel Basic Oxygen Furnace Open Hearth Furnace Scarfing Machine Hand . References: Bohn, R. , T. 1.0 0.7 0.6 4.4 0.2 1.5 3.7 0.5 0.17 0.005 0.11 Cuscino and C. 50 60 60 10 15 85 85 65 90 100 100 Cowherd, Fugitive Emissions Fugitive 30,000 20,000 3,000 8,000 1,200 3,800 27,000 13,000 1,800 30 700 from Integrated Stacks Not Applicable Not Applicable Not Applicable 52,000 Not Applicable ]• 13,000 12,000 4,000 } 100 Iron and Steel Plants, EPA-600/2-78-050, March 1978. Zoller, J., G. Wood, and T. Janszen, "Current Status of Process Fugitive Particulate Emission Estimating Techniques," Second Symposium on Fugitive Emissions: Measurement and Control Held in Houston. Texas on May 23-25, 1977, EPA-600/7-77-148. December 1977. Jacko, R., "Coke Oven Emission Measurements During Pushing," Symposium on Fugitive Emissions Measurement and Control (May 1976, Hartford, CT). EPA-600/2-76-246, September 1976. Kenson, R., N. Bowne, and W. Cote, "The Cost Effectiveness of Coke Oven Control Technology," Symposium on Fugitive Emissions Measurement and Control (May 1976, Hartford, CT). EPA-600/2-76-246, September 19 ------- TABLE 2. FUGITIVE EMISSIONS FROM IRON AND STEEL PLANT OPEN SOURCES (NATIONWIDE TOTALS IN 1976) Source Estimated Emissions Less Than 30 pm, Tons Unloading Raw Materials Conveyor Transfer Stations Storage Pile Activities Vehicular Traffic Wind Erosion of Exposed t»> Areas 1 ,400 2,500 19,000 32,000 1,800 Estimated Emissions Less Than 15 pm, Tons (By Interpolation) 950 1,900 13,000 24,000 1,200 Estimated Emissions Less Than 5 pm, Ton1 470 1,000 5,700 13,000 540 Reference: Bohn, R., T. Cuscino, and C. Cowherd, Fugitive Emissions From Integrated Iron and Steel Plants, EPA-600/2-78-050, March 1978. ------- TABLE 3. RANKING OF IRON AND STEEL FUGITIVE EMISSION SOURCES Source Coke Ovens Electric Arc Furnace Vehicular Traffic unpaved paved Basic Oxygen Furnace Storage Pile Activity Sintering Open Hearth Furnace Hot Metal Transfer Conveyor Transfer Operations Scarfing Wind Erosion Unloading Raw Materials Rank in Total Fugitive Emissions 1 2 \ J 4 5 6 7 8 9 10 11 12 Percent Less 15 ym 60 85 45 70 65 10 • 10 90 15 40 100 6 7 Than 5 urn 40 70 25 40 50 5 5 65 10 20 90 3 3 ------- TABLE 4. FUGITIVE PROCESS EMISSIONS FROM PRIMARY LEAD SMELTERS Process Estimated Uncontrolled Fugitive Emission Rates Ib/Ton Product Lead Estimated Percent of Mass Less Than 15 Micron Railroad Car and Truck Unloading Materials Storage and Transfer Limestone Silica Concentrate Iron Ore Coke Mixing and Pelletizing Sintering Blast Furnace Slag Pouring and Disposal Zinc Fuming Furnace Dross Kettle Reverberatory Furnace Leakage Lead Casting .67 .21 .02 5.8 .74 .15 2.2 21.1 .15 3.4 4.6 .48 3.0 1.87 50 80 80 80 80 80 ; 95 90 , ' 70 100 100 100 95 Sources: Uncontrolled emission rates from PEDCo Environmental, Inc. Technical Guidance for Control of Industrial Process Fugitive Particulate Emissions. EPA-450/3-77-010, U.S. Environmental Protection Agency, Research Triangle Park, N.C., 1977. Pp. 2-130 - 2-163. Size data from several sources noted in Figure 2 legend. ------- TABLE 5. FUGITIVE PROCESS EMISSIONS FROM PRIMARY COPPER SMELTERS Process Estimated Uncontrolled Fugitive Emission Rates Ib/Ton Product Copper Estimated Percent of Mass Less Than 15 microns CT> Unloading of Concentrate Materials Storage and Transfer 33.7 50 Ore Concentrate Limestone Flux Roaster Charging and Leakage and Calcine Transfer Reverberatory Furnace: Charging, Leakage, and Tapping Converter: Charging,. Leakage, and Tappiny Blister Copper: Furnace Charging and Tapping 1.1 .5 23.0 8.5 12.0 4.4 80 80 No data, see note 95 95 20 Note: No reliable fugitive size data available. Might expect fugitives to be similar in size to fugitives from ore concentrate materials handling i.e., 80 percent less than 15 microns. Sources: Uncontrolled emission rates from PEDCo Environmental, Inc. Technical Guidance for Control of Industrial Process Fugitive Particulate Emissions. EPA-450/3-77-010, U.S. Environmental Protection Agency, Research Triangle Park, N.C., 1977. Pp. 2-130 - 2-163. Size data from several sources noted in Figure 2 legend. ------- Other data, presented in this paper but not shown in the summary, deal with zinc and aluminum processing. From the limited information available, it may be concluded that zinc and aluminum, like copper and lead, give rise primarily to respirable particles although emissions from aluminum operations may be generally larger than from the other three. In review of emission data, nonferrous metal industrial operations give rise primarily to small or respirable particles with only one exception which is not a major source in copper processing. However, for iron and steel industrial operations many sources which release large particles have been identified. These sources are sintering, hot metal transfer, and open sources. Sintering and two of the open sources—vehicular traffic and, storage pile activities-- are major sources and combined account for almost a third of iron and steel fugitive dust. An important question is the application of control technology for different air pollution prevention strategies. Control to prevent total suspended parti- culate (TSP) will be the same as control to prevent respirable particulate matter (IPM) if the emissions to be controlled are primarily in the respirable size range. This is true for nonferrous metal industrial fugitive emissions and for two thirds of the iron and steel industry fugitive emissions. Controls applied to sintering and open sources would have to be better to meet the same level of TSP instead of IPM requirements. If greater control were needed to meet lower levels of IPM allowable, costs for control on all sources would increase greatly because no. control _for fugitive emissions is highly efficient. Application of control to meet a high standard could not be inexpensively modified to provide control to a lower level. ------- II. OVERVIEW OF FUGITIVE CONTROL TECHNOLOGY Perhaps the state of industrial fugitive process particulate (IFPP) controls can best be characterized by the terms "emerging" and "site-specific." Only within the last two to three years have IFPP emissions been studied and means for their measurement and control considered. The sources of IFPP emissions are numerous and quite varied, not only from industry to industry, but also between different sources within the same plant. Accordingly, the control equipment requires design and development almost on a case by case basis. For example, the hooding required to collect fugitive emissions from pushing coke is entirely different from that used in collecting offgases from blowing a copper converter. Not only is the mechanical design different but particulate removal efficiency can vary widely due to differences in air flow, ambient conditions, etc. The central points here are: (1) control technology for fugitive emissions is new and changing; and (2) the industrial applications are highly individual and it is much more difficult to generalize than in the case of stack emissions. In the future, it is unlikely that any single method of fugitive control will predominate and we can expect the process systems will continue to require individual control strategies. By definition, fugitive emissions are difficult to collect and control. They are diffuse and typically come from many small sources as opposed to a single large emitter. For example, in a primary lead smelter, twenty-five different groups of emission sources have been identified,' • with each group containing several emission sources within the plant. Fugitive emissions can also be diffuse in the sense that there are low level emissions from a large area as in the case of wind erosion from storage piles or dust from in-plant vehicular traffic. Many of the fugitive emissions are intermittent in nature. Unloading railcars or slag dumping are two good examples of intermittent fugitive emissions— the only significant emissions are during the five to ten minute period during the dumps. Control equipment is not required the remainder of the time. Process upsets and abnormal feeds can also be the cause of intermittent, high level fugitive particulates. Because.of the intermittent and diffuse nature of fugitive emissions their measurement is difficult. Briefly, sampling can be via (1) quasi-stack sampling 8 ------- where a collection hood near the source is sampled; (2) roof monitor sampling in which a large enclosed area such as a building is sampled; or (3) upwind- downwind sampling where fugitive emissions are back-calculated from particulate measurements around the source perimeter. Accuracy of such methods varies from (?} > -'~ -•. • 50 to 500 percent.v; Because of the relatively recent interest in fugitive process emissions and the measurement difficulties, data on the size and rate of IFPP emissions are spotty and often several fugitive sources are grouped together for measurement pur- poses. Field data on control device efficiencies is even more scarce. In the sections on control equipment and particulate characteristics which follow, engineering judgement and the results of a recent,literature survey were used to provide information relevant to a standard based on particulate matter less than 15 microns. III. EQUIPMENT FOR CONTROL OF FUGITIVE EMISSIONS Some degree of fugitive particulate control can be obtained with little or no equipment investment via good housekeeping and plant maintenance practices. Prompt repair of hood damage, maintenance of seals on coke oven doors, the proper handling and disposal of dusts from fabric filters, quick clean up and disposal of particulate spills, and any of the numerous other elements of good manufacturing practice all serve to reduce the amount of fugitive particulate emissions. This type of control depends on work practices; equipment costs (if any) for these control measures would be independent of whether the standard was based on total suspended particulate or the minus 15 micron fraction. For open source fugitive particulate emissions such as agricultural tilling, construction activity, and traffic on unpaved roads, water suppression is the major means of fugitive particulate control. Wetting with sprays can also be used to reduce fugitive process particulates from storage bins, conveyors, or raw materials storage. Additives of various sorts may be used to form a "crust" on /3\ the particulate and improve control efficiency.v ' Some recent work has been directed at removing suspended fugitive particulates with charged water sprays.^ ' It was found that most particulates carry a negative electrostatic charge and by inducing a positive charge on water droplets, good removal of respirable size particulates is achieved. A small version of the charged water sprayer suitable for conveyor transfer points, grinding wheels, etc. has recently been marketed.* f o) *Electrostatic Fogger..Iv-A, Ransburg Corp., Indianapolis, Ind. Mention of company or product names is not to be considered an endorsement by the U.S. Environmental Protection Agency. .,,:-.-.•-. ------- IERL-RTP is currently directing an evaluation of this device for fugitive control (5) in lead and copper smelters. ' A serious disadvantage of water spray suppression is that it can only be used when (1) the process and product can tolerate the additional water and (2) when capture of the particles is not required. Water sprays help agglomerate suspended particulates so they settle out of the air faster, but they do not, by themselves, collect the settled material. This is not a disadvantage for bins, car unloading, or conveyor transfer points where the settled material returns to the process. However, in many other applications, the settled particulate would dry out and be resuspended. . To remove fugitive particulates from a gas stream, conventional control devices are used: predominantly bag filters, also electrostatic precipitators scrubbers, and in some cases cyclones. However, for fugitive emissions, the control problem is not usually the removal of particulates from the gas, it is instead the gathering and collection of the gas streams. Emissions from the many diffuse sources of fugitive particulates must be gathered and transferred to the control device via a ventilation system. Ventilation systems for fugitives are typically either secondary hooding at the local source of emissions or total building enclosure and evacuation. Both methods have their drawbacks and, for large airflows, have high energy and capital requirements. The ventilation system for collecting fugitives requires individual consideration for each fugitive source. Personnel and equipment » access must be considered, the areas to be vented must be selected, and ductwork layout can be difficult in retrofitting existing plants. For an overview of the various fugitive control methods used in industry consult Tables 6-12 reproduced from Reference (6). Reference (1) is also a good source of data on fugitive particulate sources for various industries. 10 ------- TABLE 6 . FUGITIVE DUST CONTROL FOR MATERIALS HANDLING SOURCES Source Type of Control Relative Estimated Effectiveness Remarks or Restrictions Conveyors, Elevators, and Feeders Sprays at trans- fer points In-PI ant Hauling Loading and Unloading Rail car or truck Barge or Ship Foam sprays Enclosure of transfer points and exhaust Complete enclo- sure and exhaus- ting to control device Scraper — ^Wetting Stabilization Enclosure Exhausting Enclosure or hooding 6"f hatches Reduction of fall distance Wet Suppression Pneumatic System Tarpaulins over holds Reduction of fall distance F to G F F to G F G P to F P to F G P to F P to F Can use water or water plus a surfactant. Cannot be used where wet product is intoler- able to later process steps. Could be costly Costly—must" be ducted to control device. Used to remove sticking material from belt. Effective in combination with other controls. Wetting of transported material is a temporary control but is effec- tive for short hauls. Not cost effective for short hauls. Costly By use of rock ladders, telescoping chutes, etc. Only applicable if wet product can be tolerated. Costly May establish a positive pressure in hold. There- fore, venting may be needed. Still causes disturbance of surface. Depending on material, could become clogged. continued 11 ------- TABLE 6. (cont'd) Source Bagging Stacking of Products Type of Control Relative Estimated Effectiveness Remarks or Restrictions Barge or Ship (cont'd) Canopy with exhaust Enclosure and exhaust of receiving hoppers Enclosure of receiving hoppers F to G F to G F Requires a control device—costly. Requires a control device— costly. • Enclosure of operation Exhausting, of enclosure Reduction of fall distance Wet Suppression Enclosure Waste Disposal Wet Material Handling Dumping Covered or enclosed hauling system Sprays Enclosure F to G P to F P to F G P to F F May lead to problems of equipment abrasion due to retained dust—requires periodic cleaning. Extra cost for control Use of telescoping chutes, rock ladders, hinged-boom conveyors, etc. Temporary only May not be feasible due to type or amount of material. May be impractical due to type of material or disposal area. May pre- sent additional problems such as solubilization of metals, etc. Costly May be impractical 12 ------- TABLE 7'. FUGITIVE DUST CONTROL FOR STOCKPILES AND VIASTE DISPOSAL HEAPS Relative Estimated Source Type of Control Effectiveness Remarks or Restrictions Stockpiles Waste Disposal Heaps Coal Refuse Pile Fires Wetting Stabilization , P Enclosure F to G Wind Screen VP Separation of F fines that are sent to enclosed areas Wetting . P Stabilization P to F Vegetation F to G Physical F to G Stabilization Wetting VP Trenching VP Covering, etc. VP Continuous operations on stockpiles preclude effective control. Same as wetting May not be practical for all types of operations. Extra cost Temporary only Efficiency depends on type of material, type of stabilizer, etc. Temporary May be expensive due to cost of pretreating (fertilizing, etc.). No effective control No effective control No effective control 13 ------- TABLES'. FUGITIVE DUST CONTROL METHODS FOR MINING OPERATIONS Source Type of Control Relative Estimated Effectiveness Remarks or Restrictions Overburden Removal Drilling Blasting Excavating and Loading Wetting VP Water, foam F to G or surfactant injection Hooding and 6 collection system Wetting VP Water ampul VP steming Proper technique P Wettina P Continuous activity negates effective control Baghouses are common controls—costly. No effective control No effective control No effective control Continual disturbance precludes effective control 14 ------- TABLE 9. FUGITIVE DUST CONTROL FOR SOLIDS BENEFICIATION SOURCES Source Type of Control Relative Estimated Effectiveness Remarks or Restrictions Crushing Screening Classifying Wetting Enclosure Hooding and ducting to con- trol device Wetting Housing or enclosure Hooding and ducting to control device Enclosure and ducting Wet Classifica- tion Closed pneumatic system P to F F F to G P to F F to G F G Depends on type of prod- uct and crusher. Wet- ting can cause clogging. Can have problems due to abrasion of equipment by enclosed particles. Efficiency depends on type and design of con- trol and associated equipment. Wetting can cause clogging of fine screens. Not applicable for materials that require low moisture for subsequent process steps. May increase maintenance charges due to abrasion of screens. Periodic cleaning necessary. Costly--may add signifir-' cant cost per unit of product, especially in high volume, low price industries such as , crushed stone. Only applicable if material can be wet for next steps. Applicability depends on material 15 ------- TABLE 10. FUGITIVE DUST CONTROL METHODS FOR TRANSPORTATION SOURCES Source Unpaved Roads Paved Roads Transport of Fines by Truck or Train Type of Control Wet Suppression Stabilization Pavi ng Speed Reduction Washing Vacuuming Wetting Covering (tarps) Enclosure Relative Estimated Effectiveness VP P G \ Variable P P. P • F G Remarks or Restrictions Temporary Temporary Cost—without improve- ment of road leads to psychological over- driving Costly, temporary Costly, .temporary Temporary only Problems occur during Off-Highway Travel Road Shoulders None Stabilization Vegetation F G loading and unloading and from leakage. Also costly. lfiL ------- TABLET!. FUGITIVE DUST CONTROL FOR CONSTRUCTION SOURCES Source Type of Control Relative Estimated Effectiveness Remarks or Restrictions Excavating Heaping of Excavated Materials Wetting Wetting Stabilizing VP to P P F to G Vehicle Travel See Unpaved Roads (Table 7) Demolition None Continual working pre- cludes effective control. Temporary only Stabilizing with a bind- er is an effective control method that is applicable to short term .heaping of excavated material. Demolition may cause high, short-term exposure to asbestos from bulding materials. TABLE 12', FUGITIVE DUST CONTROL OF MISCELLANEOUS SOURCES Source Type of Control Relative Estimated Effectiveness Remarks or Restrictions Roof Monitors Open Burning Incineration Cooling Tower Drift Ducting to control device None Control Device F to G F to G Effectiveness depends on type of material and type of control Costly No effective control 17 ------- IV. FUGITIVE EMISSION CHARACTERISTICS Particle size distributions for various fugitive emissions are shown in two figures—Figure 1 for the iron and steel industries and Figure 2 for the nonferrous metallurgical industries. The accompanying legends give the source of the emissions together with the literature references. Characteristics for some of the fugitive emissions have been estimated from ducted sources. Note that for the majority of the nonferrous sources, most of the fugitive emission mass is below the proposed standard of 15 micron while for iron and steel sources the size range is broader. . We would expect the fugitive emissions measured at the plant boundary to have fewer larger particles because these would settle out inside the plant boundaries. However, it should be noted that the ultimate fate of fugitive particulate emissions from an industrial process is not well known. It depends in general on the height of the emission point, on the location of surrounding structures, on meteorological conditions at the site (particularly wind patterns), on the topography of the area, and on the size distribution of the emissions. For example, mathematical modeling^ ' has shown that the average drift distance of 15 micron particles emitted 3 meters above the level of surrounding structures can vary from 300 to 800 meters depending on topography alone. (Almost a 300 percent variation.) The correspondong drift distance of 5 micron particles varies from 2 to 6 kilometers. This means, of course, that the achievement of any ambient suspended particulate standard depends not only on the above factors, but is also highly affected by the point and method of compliance testing. A change in the sampling method or point or in the size basis of ambient standards could easily reverse the compliance status of any particular site for either a total or a minus 15 micron standard. More detailed information on fugitive particulates from three areas in which we have done the most work is given below. A summary of the detailed information below is presented in Section I - Summary, Tables 1 through 4. IV. A. Integrated Iron and Steel Plants Fugitive emissions originate from several individual processes as well as from open sources in an integrated iron and steel plant. Table 1 in Section I summarizes the estimated process fugitive emission rates and size characteristics and compares the relative magnitude of the process fugitive emissions (with 18 ------- FIGURE 1. PARTICLE SIZE DISTRIBUTION DATA FOR IRON AND STEEL INDUSTRY 1 I I I I l l I I i i i t t i LA 57.? - 99.« - 90 - 20 - 7O 6O ro 10 3O 10 -^ /O r x i.o Ul u> {2. Ul U) s: O Ste ACCOM? Aw^lNiCr- FOR SO Of- <•-<=•=> OB T>A .or 1 ) I II f I I I l i l l i l i IOC I 1 I I I l I I 10' I I I I ------- LEGEND FOR FIGURE 1 PARTICLE SIZE DISTRIBUTION FOR IRON AND STEEL INDUSTRY Curve Number Fugitive ParticuTate Source Reference 3 4 5 6 7 8 10 11 Coke Pushing Sintering Machine Hot Metal Transfer Electric Arc Furnace Basic Oxygen Furnace Open Hearth Furnace Scarfing Raw Material Handling and Storage Pile Activity Vehicular Traffic (Unpaved Roads) Vehicular Traffic (Paved Roads) Conveyor Transfer Stations PEDCo Environmental, Inc. "Technical Guidance for Control of Industrial Process Fugitive Emissions," EPA-450/3-77-010, (1977) Bohn, R., T. Cuscino & C. Cowherd, "Fugitive Emissions From Integrated Iron and Steel Plants," EPA-600/2-78-050, (1978) ditto . ditto ditto ditto ditto ditto ditto ditto ditto 20 ------- FIGURE 2. PARTICLE SIZE DISTRIBUTION DATA FOR NONFERROUS METALS INDUSTRY i i i 11 1 I L 1 1 I I I I I I I I t I I 97.S - 9? •- n - TO to SO 10 30 Ul tO 5" 1 I. fl- H '•"I Z Zi vj oc .01 • T—r-f-r 10' I I I I I I I I 10° I I I I I I I in' .. i t i i i i ------- LEGEND FOR FIGURE 2 PARTICLE SIZE DISTRIBUTION DATA FOR NONFERROUS METALS INDUSTRY Curve Number Fugitive Particulate Source Reference 2 3 4 5 6 7 8 10 Metal Melting, Secondary Aluminium Smelting Metal Melting, Secondary Brass Smelting Metal Melting, Secondary Bronze Smelting Metal Melting, Secondary Lead Smelting Metal Melting, Secondary Zinc Smelting Blast Furnace Stack Gases, Secondary Lead Smelting Sintering Machine ESP Inlet, Primary Zinc Production Fugitives, Sintering Building, Primary Lead Production Pouring and Casting, Primary Copper Smelting Reverberatory Furnace, Primary Copper Smelting Jones, H. R. Pollution Control in the Nonferrous Metals Industry, 1972, Noyes Data Corp., Park Ridge, N.J. ditto ditto ditto ditto ditto Harris, D. B. and D. C. Drehmel. Fractional Efficiency of Metal Fume Control as Determined by Brink Impactor. Presented at 66th Annual Meeting of the APCA, Chicago, Illinois. June 24-28, 1973. Constant, P., M. Marcus, and W. Maxwell. Sampling Fugitive Lead Emissions from Two Primary Lead Smelters. EPA- 450/3-77-031. U.S. EPA (1977). PEDCo Environmental, Inc. Technical Guidance for Control of Industrial Process Fugitive Particulate Emissions. EPA- 450/3-77-010, U.S. EPA, (1977). Thompson, G. S., Jr. and G. B. Nichols. Experience with Electrostatic Precipitators as Applied to the Primary Copper Smelting Reverberatory Furnace; in Proceedings: Particulate Collection Problems Using ESP's in the Metallurgical Industry. EPA-600/2-77-208, U.S. EPA, (1977) 22 ------- LEGEND FOR FIGURE 2 (CONTINUED) Curve Number Fugitive Particulate Source Reference 11 12 13 14 15 16 17 Limestone Storage and Material Handling Fugitives, Blast Furnace Tapping Area, Primary Lead Smelting Fugitives, Ore Storage Bins, Primary Lead Smelting Fugitives, Blast Furnace Charging Area, Primary Lead Smelting Sintering Baghouse Inlet, Primary Lead Smelting Converter ESP Inlet, Primary Copper Smelting Roaster ESP Inlet, Primary Zinc Production PEDCo (1977). Constant et al (1977) Constant et al (1977) Constant et al (1977) Harris'and Drehmel (1973), Harris and Drehmel (1973) Harris and Drehmel (1973) 23 ------- currently typical controls applied) to controlled stack emissions from the same processes. It should be noted that most of the fugitive emission estimates are based on sparse data and extrapolations from stack measurements. At individual plants the fugitive emission rates could quite possibly vary from -50 percent to +200 percent of the tabulated values. 'Table 2 in the same section gives estimates of controlled particulate emissions nationwide in 1976 from open sources in iron and steel plants. The estimates are in terms of total mass less than 30 urn and.total mass less than 5 ym with mass less than 15 ym determined by log-normal interpolation. These estimates are based on sampling at a relatively small number of plants with extrapolation to yield the nationwide totals. The\immediate conclusion is that fugitive emissions from vehicular traffic and from storage pile activities are relatively large in comparison to process fugitive emissions although the relative significance of the sources will in general vary from plant to plant. Each of the sources, both process and open is discussed briefly below. Coke Ovens . In terms of total mass on a nationwide basis, coke oven emissions are the most significant source of fugitive emissions and .perhaps the most difficult to (&} control. The following comments, extracted from a recent paper^ ' on coke oven emission control, give a concise summary of the emission problems and present control strategies: "Coke. Oven CkaA.gi.ng The charging of coal into coke ovens results in a fugitive emission release consisting of coal dust, tars and gases from the charging hole. Control tech- nologies considered commercially feasible for prevention for prevention of substantial charging emissions include: Stage charging with oven evacuation 0 Larry cars equipped with gas collecting systems and wet scrubbers 0 Pipeline charging The former two have been considered as retrofits for present coke ovens as well as feasible for new coke oven battery construction. In some cases, pipeline charging, which is a technology considered suitable for new construction, has been installed in rebuilt batteries to meet the need for strict control of par- ticulate emissions. . 24 ------- Coking Leakage of emissions (gases, fumes) from the coke oven doors and other openings in the ovens are minor but hard to control sources of emissions. Although improved door sealing is a potential control, it is hard to estimate the degree of control achieved by this technique. Coke. Po6/ung The pushing of the incandescent coke >from the oven into the quench car results in emission of hot coke particles and tars as well as gases from the coke as it.leaves the oven and dumps into the quench car. Although there have .been commercial control equipment installations, the technology is undergoing change and new concepts are now in design stage. Commercially feasible controls include: 0 Coke side sheds ducted to wet scrubbers or electrostatic precipitators 0 Coke guide and hooded quench car Both have been considered for retrofit to present ovens and for new construction. In new construction, the hooded quench car can contain a mobile quench station which eliminates quench towers. Co fee Que.nc.ki.ng Although changes in this technology may be more related to water reuse and pollution, they do result in lower air pollution emissions. Commercially feasible control technologies include: 0 Dry quenching 0 Coke guide and hooded quench car (with mobile quench station) Both technologies have been primarily considered for new installations rather than retrofit." This same paper concludes that stringent (and costly) controls can reduce local suspended particulate concentrations significantly, but compliance problems may still exist if the ovens are located within a few thousand feet of the plant boundary. Sintering Machines . Sintering operations can emit fugitive emissions at the end of the strand where the sinter is broken, at the cooler and on the cold screen. The emissions are relatively large in size and probably do not travel far from the machine by air. In some installations, one or more of these potential fugitive emission points is hooded and the emissions are ducted to a baghouse or other collector. 25 ------- Hot Metal Transfer In plants where hot metal is transferred from the blast furnaces to steelmaking furnaces, iron oxide and.kish (a carbonaceous material) emissions are produced during the pouring operations. Where controls exist, the most common practice is hooding roll owed by fabric filtration. Steelma'king Furnaces > Fugitive emissions are associated with all three types of steelmaking furnaces. They occur primarily during charging, slagging and tapping operations although significant leakage through various ports and loose-fitting covers may occur throughout the cycle in some installations.. Alternate control strategies involve primarily deciding the type of hooding (close fitting vs. canopy vs. building evacuation). Once the emissions are ducted, any of the conventional stack gas control devices can be used. Scarfing In the scarfing operation, in which a thin layer is burned off the surface of the steel to create a better finish, a very fine iron-oxide particulate is formed. The scarfing area is frequently hooded and the emissions are sent to a scrubber or wet precipitator. Unloading Raw Materials and Conveyor Transfer Stations • Fugitive emissions occur when raw materials are unloaded from barges, rail cars, or trucks and transferred to conveyors. Emissions are also usually apparent where the material transfers from one conveyor to another if dropping or physical mixing occurs. These material-handling emissions can be reduced by enclosing the unloading or transfer points or by the use of liquid sprays to suppress the dust. Storage Pile Activities Fugitive emissions can occur due to loading and unloading at the pile, wind erosion of the pile surface, and local vehicular traffic that is related to maintaining pile configuration. Emissions from unloading activities can be reduced to some extent by reducing the drop distance of the materials. Enclosures and spray systems can reduce emissions from the other phenomena. 26 ------- Vehicular Traffic Motor vehicle traffic is associated with employee arrival and departure, employee transportation within the typically large plant areas, ans transportation of raw and finished materials by truck. Although the inter-plant roads are frequently paved, fugitive emissions can be substantial when the surface dust loading is allowed to accumulate. These emissions can be reduced by paving unpaved roadways, by periodically watering, oiling, or flushing the roads (runoff can create water pollution problems), or by sweeping (which can aggravate the problem more than solve it unless vacuum sweepers are used). Wind Erosion of Exposed Areas \ Bare, unused land areas within the plant are susceptible to wind erosion. Although the magnitude of this problem is relatively small, it can be alleviated by paving or other surface stabilization or by wind breaks. IV. B. Primary Lead Smelting In producing metallic lead from ore concentrate, three major steps are involved: (1) sintering in which the lead sulfide ore is burned to lead oxide; (2) blast furnace in which coke is. added to the sinter to reduce the lead oxides to molten lead; and (3) refining in which remaining impurities are removed from the molten lead. Sintering is the largest potential source of fugitives^ ' with materials handling operation also being a major source. See Table 4 in Section I for a summary of rate and size data. Midwest Research Institute (MRI) conducted actual plant measurements of fugitive emissions from two ASARCO primary lead smelters: the Glover, Missouri plant and the East Helena, Montana plant.* ' Because of the measurement problems associated with individual sources, fugitive emissions from an entire operation (such as the sintering building) were measured as one fugitive source. MRI determined the particle-size range of total particulate fugitive emissions for four locations at the Glover plant: (1) sintering building, (2) blast-furnace tapping area, (3) blast-furnace feed charging area, and (4) ore storage bin area. A Sierra, Model 230, HiVol cascade impactor was used. A Sierra impactor was also used to determined the particle size range for total fugitive emissions from the East Helena blast furnace operations. The results are summarized in Table 13. 27 ------- TABLE 13. PARTICLE,DISTRIBUTION FOR FUGITIVE PARTICULATES FROM LEAD SMELTING Location Sinter .building, G.I over, Missouri Blast furnace (tapping operations), Glover, Missouri Blast furnace (.charge-feed area) Glover, Missouri Ore-storage-bin area Blast furnace operations East Helena, Montana Concentration (yg/m3) w.t-% - • 1,420* 207 174 112 117 116 , 44.1 39 32.7 24.7 40.4 75.7 1,301 79.1 82.1 81.2 190 338 372 36.6 54.4 45.1 89.5 177 652.0 375.0 242. 0 132.0 102.0 71.1 66.18 9.64 8.11 5.22 5.45 x 5.40 17.19 15.20 12,74 • 9.62 15.74 29.51 62.81 3.82 3.96 3.92 9.17 16.32 48.03 4.72 7.02 5.82 11.55 22.86 41.43 23.82 15.37 8.38 6.48 4.52 Particle Size Range micron <0.38 0.38-0.71 0.71-1.15 1.15-2.3 2.3-5.6 . >5.6 <0.31 0.31-0.59 0.59-0.95 0.95-1.9 1.9-4.6 >4.6 <0.33 0.33-0.63 0.63-1.0 . 1.0-2.03 2.03-4.9 >4.9 <0.31 0.31-0.59 0.59-0.95 0.95-1.9 1.9-4.6 >4.6 <0.31 0.31-0.59 0.59-0.95 0.95-1.9 1.9-4.6 >4.6 Source: Constant et al (1977) 28 ------- Particle sizes as determined by Harris and Drehmer ' with a Brink impactor gave the data in Table 14 for ducted emissions from a lead sintering machine. Some idea of the size distribution of fugitive particulates outside the boundary of a lead smelter can be gained from data by Dorn et_a]_. ' They measured lead, cadmium, zinc, and copper levels in suspended particulate over winter, spring, and summer seasons at a site approximately 800 meters north of a lead smelter. An eight-stage Andersen impactor sampler was used. While they did not present total particulate weights versus size, a rough idea of the particles in the respirable range can be gained from the elemental distributions in Table 15. (Complete elemental distribution data is given in Table 16.) IV. C. Primary Copper Smelting x The production of copper metal from the ore consists of.four major steps: (1) roasting in which part of the sulfur in the ore is burned (this step has been eliminated in many smelters today); (2) srne 11in g in which the roasted ores are melted to produce a molten "matte" consisting of copper and iron sulfides; (3) converting in which the molten "matte" is blown with oxygen to produce a fairly clean "blister copper"; and (4.) refining in which any final impurities are removed. Table 5 (in Section I) identifies the largest potential source of fugitive particulates as materials unloading with converter operations also a strong source. (Roasting can also be a large source but it being eliminated as a process step in many smelters.) There has been no study of fugitive emissions from copper smelters comparable in scope to the MRI report on fugitives from lead smelters. Data scattered throughout the literature are presented here. Harris and DrehmeV ' provided the values in Table 17 for particulates from a copper converter as sampled by a Brink, Model B,5 stage impactor. (12) A separate set of data from Thompson and Nicholsv ' falls in line with the smaller range of sizes. They measured particulates from two copper reveratory furnaces with cascade inertial impactors and five stage cyclones. Data estimated from two figures in Reference (12) is given below in Table 18. The particulate entrained from handling limestone flux for the copper process has a mean dian:3ter of 3-6 microns. ' It is reasonable to expect the mean diameter of fugitives from copper concentrate storage to be approximately the same size range. . • ' ' 29 ------- TABLE 14. PARTICLE DISTRIBUTION FOR DUCTED LEAD SINTERING MACHINE GASES Particle size (microns). >3.i 1.8-3.1 1.25-1.8 0.62-1.25 0.38-0.62 <0.38 Total Particle (g/scf) .04077 .01622 .02599 \ .05938 .06676 .02062 .22974 Loading (wt %) 17.75 7.06 11.31 25.85 29.06 8.97 100.00 Source: Harris and Drehmel (1973). 30 ------- TABLE 15. PERCENT DISTRIBUTION OF Pb, Cd, Zn, Cu IN RESPIRABLE RANGE NEAR PRIMARY LEAD SMELTER Particle Size (microns) I4-7 < 4.7 Pb. 34.29 65.71 Element Cd 11.69 88.31 and % Zn 27.09 72.91 Cu 45.68 54.32 SOURCE: Dorn et al. (1976) 31 ------- TABLE 16. AIRBORNE ELEMENTAL CONCENTRATIONS NEAR PRIMARY LEAD SMELTER Size (microns) 1 11 7-11 4.7-7. 3.3-4.7 2.1-3.3 1.1-2.1 0.65-1.1 0.43-0.65 TOTAL Pb yg/m3 wt% 0.1064 0.0733 0.1768 0.1655 0.0691 0.1430 0.1651 0.1372 1.0361 10.26 7.07 17.06 15.97 6.67 13.80 15.93 13.24 100.00 Elemental Concentration Cd Zn yg/m3 wt% yg/m3 wt% 0.0009 0.0007 0.0013 0.0014 0.0011 0.0064 0.0071 0.0059 0.0248 3.63 2.82 5.24 5.65 4.44 25.81 28.63 23.79 100.00 0.0194 0.0113 0.0166 0.0163 0,0140 0.0307' 0.0343 0.0320 0.1746 11.11 6.47 9.51. 9.34 8.02 17.58 19.64 18.33 100.00 Cu yg/m3 wt% 0.0042 0.0018 0.0029 0.0026 0.0015 0.0016 0.0008 0.0040 0.0194 21.65 9.28 14.95 13.40 7.73 8.25 4.12 20.62 100.00 SOURCE: Dorn et al. (1976) ------- TABLE 18. PARTICLE DISTRIBUTION FOR DUCTED COPPER REVERBERATORY FURNACE GASES PLANT A PLANT B Particle Size (microns) (mg/acm) wt% mg/acm wt% > 4 2-4 1-2 0.6-1 0.3-0.6 <0.3 10 20 31 27 24 28 7 14 22 20 17 20 80 50 40 38 65 17 28 17 14 13 22 6 Source: Figures 2 and 5; Thompson and Nichols (1977) 34 ------- In the period from 1965 to 1973 NIOSH collected data on trace metal levels in copper smelters. ' Samples from many smelters were obtained and used to get long term industry-wide averages of exposure for the following smelter areas: (1) reverberatory furnace charging'deck, (2) reverberatory furnace operators deck, (3) converters, and (4) anode casting. Both personal and area samples were collected. Membrane filters with a 0.8 ym pore size were used to collect metal fumes and dusts, which were then analyzed by atomic absorption. Table 19 presents the results of these tests. In an attempt to distinguish between "respirable" and "non-respirable" metal concentrations, the NIOSH workers took some samples through a cyclone before analyzing for metals collected on the filter. No data is given on the particle size corresponding to "respirable" but Table 20 shows the results for 23 data points for converter furnace and crane aisle employees. If we assume the metals other than Cu and As were distributed evenly between sizes we get an estimate of 50-60 weight percent of the fugitives in the "respirable" size range. 35 ------- TABLE 19. ELEMENTAL CONCENTRATIONS IN AIR BY COPPER SMELTER AREA INDUSTRY WIDE AVERAGES Area Reverberatory Furnace Charging Deck Reverberatory Furnace Operators Deck Converter Aisle en Anode Casting Area Sampling (mg/M3) Pb .07 .06 .05 .01 Zn Cu .07 1.1 .12 2.3 .05 .22 <.01 .13 As Cd .04 ,005 .02 .012 .01 .003 <.01 .001 Mo .014 .015 .004 No data Pb .07 .07 .03 .01 Personal Sampling (mg/M3) Zn .12 .07 .04 .01 Cu 3.4 1.3 .11 .07 As No data No data No data No data Cd .005 .006 .004 <.001 Mo .003 .03 No data No data Source: Wagner (1975). ------- TABLE 20. PERCENT OF METAL AEROSOLS IN RESPIRABLE^ RANGE CONVERTER, FURNACE AND CRANE AISLE EMPLOYEES IN A U.S. COPPER SMELTER Metal Pb Zn Cu As Cd Average %(3) Respirable(2) 52.1 , 59.5 6.1 75.2 49.5 adapted from Wagner (1975). No size given for "respirable." Larger aerosols were removed using a miniature cyclone before collecting remainder on a filter. *• '23 data points each except As only has 14 data points. . ' ... 37 ------- V. CONTROL FLEXIBILITY AND FACTORS AFFECTING COMPLIANCE The critical factor in reducing the overall emission rate of process fugitive particulates is not how efficiently the control device removes particulates from the ducted gases. Instead, the overall effectiveness is determined by how well the ducting and hoods gather fugitive particulates and how many of the various fugitive sources are controlled. There is little room to "fine-tune" overall removal by varying the design of the central control device—any flexibility in system performance would come from varying the fraction of the numerous fugitive sources which are hooded and routed to the central control device. We do not now have the technology to be able to accurately predict the relative reduction attributed to various fugitive sources, so attempting'to meet standards by partial control would be a risky, trial-and-error process. , Since the primary problem with current control methods is one of containment of the gases rather than removal of the particles from the gas stream, the impor- tance of an ambient standard based on a 15 ym upper size limit as opposed to total. suspended particulate does not seem to be critical. In addition, most of the emissions are less than 15 ym in size and the large particles are more apt to settle before reaching, plant boundaries. For open sources of fugitive emissions within the plant area, the emission characteristics and rates are very poorly defined. In these applications, the efficiency of proposed controlmethods is also not as well established as the methods for process sources, which are based on ducting and conventional particuiate removal. 38 ------- VI. REFERENCES 1. PEDCo Environmental, Inc. Technical Guidance for Control of Industrial Process Fugitive Particulate Emissions. EPA-450/3-77-010, U.S. Environmental Protection Agency, Research Triangle Park, N.C., 1977. 2, Kolnsberg, Henry J. A Guideline for the Measurement of Air-borne Fugitive Emissions from Industrial Sources, in Symposium on Fugitive Emissions Measurement and Control (May 1976; Hartford, Connecticut). EPA-600/2-76-246, U.S. Environmental Protection Agency, Research Triangle Park, N.C., 1976. Pp. 33-50. 3. Dean, K. C., R. Havens, and M. W. Glantz. Methods and Costs for Stabilizing Fine-Mineral Wastes. U.S. Department of the Interior, Bureau of Mines, R.I. 7894, 1974. .. \ 4. Hoening, Stuart A. Use of Electrostatically Charged Fog for Control of Fugitive Dust Emissions. EPA-600/7-77-131 , U.S. Environmental Protec- tion Agency, Research Triangle Park, N.C., 1977. 59p'. 5. Research Triangle Institute. Assessment of the Use of Fugitive Dust Control Devices. EPA Contract No. 68-02-2612, Task 048. Task Officer D. C. Drehmel, Research Triangle Park, N.C. 6. Carpenter, B. H. and G. E. Weant, III. Particulate Control for Fugitive Dust. EPA-600/7-78-071 , U.S. Environmental Protection Agency, Research Triangle Park, N.C., 1978. 57p. 7. Cowherd, Chatten. The Impact of Fugitive Emissions of Fine Particles in Symposium on Fugitive Emissions Measurement and Control (May 1976, Hartford, Connecticut). EPA-600/2-76-246, U.S. Environmental Protection Agency, Research Triangle Park, N.C., 1976. Pp. 143-158. 8. Kenson, R. E., N. E. Bowne, and W. A. Cote. The Cost Effectiveness of Coke Oven Control Technology in Symposium on Fugitive Emissions Measurement and Control (May 1976, Hartford, Connecticut). EPA-600/2-76-246, U.S. Environmental Protection Agency, Research Triangle Park, N.C. , 1976. Pp. 247-266. 9. Constant P., M. Marcus, and W. Maxwell. Sampling Fugitive Lead Emissions from Two Primary Lead Smelters. EPA-450/3-77-031 . U.S. Environmental Protection Agency, Research Triangle Park, N.C., 1977. 407 p. 10. Harris, D. B. and D. C. Drehmel. Fractional Efficiency of Metal Fume Control as Determined by Brink Impactor presented at 66th Annual Meeting of the Air Pollution Control Association, Chicago, Illinois. June 24-28, 1973. 11. Dorn, C. R. , J. 0. Pierce, II, P.E. Phillips, and G. R. Chase. Airborne Pb, Cd, Zn and Cu Concentration by Particle Size Near a Pb Smelter; in Atmospheric Environment, v. 10, pp. 443-446, 1976. 39 ------- 12. Thompson, G. S., Jr. and G. B. Nichols. Experience with Electrostatic Precipitators as Applied to the Primary Copper Smelting Reverberatory Furnace; in Proceedings: Participate Collections Problems Using ESP's in the Metallurgical Industry. EPA-600/2-77-208, U.S. Environmental Protection Agency, Research Triangle Park, N.C.,, 1977. pp. 234-251. 13. Wagner, W. L. Environmental Conditions in U.S. Copper Smelters. U.S. Department HEW, NIOSH, Division of Technical Services, Salt Lake City, Utah, HE20.7102:C 79, April 1975. HEW Publication No. NIOSH 75-158. 40 ------- |