Document ID: EPA-HQ-OAR-2011-0344-0158
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2012-01-05T05:00Z

Quemetco, Inc., City of Industry, California ---  The Evolution of Polishing Wet Electrostatic Precipitator (WESP) Technology for Secondary Lead Process Emissions
Background:  The emissions from secondary lead smelting industry in general have declined significantly over the last 30 years.  This decline is in part due to NESHAPS (1997) and  Pb NAAQS (1978 & 2008), but also is due to new methods and technologies being researched , developed and implemented.
Define the problem:  Air emissions result from two basic sources: (1) process and (2) fugitives.  Thus, defining these two sources and designing methods and technologies to specifically mitigate them is necessary.  It is important to know that Quemetco does not categorize furnace feed/tap hoods or drying kiln transition hooding as fugitive.  These sources are process in nature. 
 Fugitives are emissions that have escaped process hooding or are generated from material handling.   In the early 1990's Quemetco identified what is believed to be the best method of controlling fugitives, i.e., total enclosure under negative pressure.  Quemetco's choice for the air movement mechanism necessary to accomplish the task was use of a skid mounted one cell pulse baghouse followed by HEPA filters in an arrangement that allows quick easy visual inspection of both sides of the HEPA filters.  These units were originally marketed for use on electronics manufacturing clean rooms.  To date Quemetco has 10 of the units pulling air out of its totally enclosed operations.  As need was identified units have been added.  Currently one more unit is scheduled.  Quemetco having in place the method / technology of reducing fugitive emissions by orders of magnitude (currently in range of 16 pounds of lead emitted per year), turned its attention to process emissions which were in the range of 615 pounds of  lead per year.
Solving the problem: Having effectively controlled fugitive emissions, around 2003 it was apparent that if further facility-wide reduction in lead emissions was to occur, then process emissions must be lowered.  The problem was Quemetco already had or was near to having the lowest process emissions in the industry using the best known off the shelf control techniques, e.g., closed dust drop out systems, baghouses (with high efficiency bags), followed by high efficiency sulfur dioxide scrubbers.  Collected dust was closed conveyed directly back the furnace feed.  Having maximized the use of known process emission control technologies, Quemetco was unaware of any technology traditionally utilized in the secondary lead smelting industry that might significantly lower its process emissions (non-fugitive stack emissions).  Quemetco identified several emission control technology vendors with technical expertise and challenged them to make a proposal to take Quemetco's process emission stacks (refinery, kiln, electric furnace and reverb furnace) and lower the emissions by an order of magnitude.   At the time the technique for the reduction had not been selected, i.e., WESP was suspected to be the best choice, but all methods/techniques were on the table.  (See Appendix _A_, the 2003 cover letter requesting proposals)
The surrogate selected by Quemetco for this reduction was the Hazardous Air Pollutant (HAP) Arsenic, not Lead.   After reviewing the received proposals, one was selected.  The vendor and Quemetco came to agreement upon guaranteed reductions for Arsenic, Lead and Nickel and begin defining how those reductions were to be accomplished and what the actual reductions would be.   The WESP system went on line in June 2008 (five years after identifying the goal).  Unfortunately, as is the case many times when developing items in unknown territory, Quemetco experienced a setback.  Specifically, a fire of unknown origin occurred in July, 2008 which significantly damaged the WESP.  Since other WESPs used in other industries are made of fiberglass that construction medium was utilized.  Of course fiberglass will burn, it caught on fire, and the plant was down for about 3 months while it was reconstructed with steel to remove the fire hazard.  In October 2008 the WESP was back on line and Quemetco was preparing to stack test for the first time.  The initial test emissions data is attached as Appendix _____.   Test emissions data for 2009 and 2010 are found in Appendices _____ and _____.  The test data show inlet and outlet of the WESP.  Immediately below is a summary of pertinent data. 

WESP Metals Reduction Efficiency - November, 2008 Test Results
                                       

                              Inlet Concentration
                                  Inlet Load
                             Outlet Concentration
                             Outlet Emission Rate
                             Reduction Efficiency
                             Reduction Efficiency

                                   (ug/dscm)
                                  (lbs.hour)
                                   (ug/dscm)
                                  (lbs/hour)
                           (%, Concentration Basis)
                              (%, lbs/hour Basis)
Arsenic
                                      197
                                   6.92E-02
                                     2.79
                                   1.06E-03
                                     98.6
                                     98.5
Lead
                                     40.7
                                   1.43E-02
                                     2.85
                                   1.09E-03
                                      93
                                     92.4
Nickel
                                     1.73
                                   6.08E-04
                                     0.73
                                   2.78E-04
                                     57.8
                                     54.3
Cadmium
                                     0.705
                                   2.48E-04
                                     0.33
                                   1.24E-04
                                     53.2
                                      50

        WESP Metals Reduction Efficiency - November, 2009 Test Results

                              Inlet Concentration
                                  Inlet Load
                             Outlet Concentration
                             Outlet Emission Rate
                             Reduction Efficiency
                             Reduction Efficiency

                                   (ug/dscm)
                                  (lbs.hour)
                                   (ug/dscm)
                                  (lbs/hour)
                           (%, Concentration Basis)
                              (%, lbs/hour Basis)
Arsenic
                                     52.67
                                   1.60E-02
                                     0.66
                                   2.14E-04
                                     98.7
                                     98.7
Lead
                                     75.81
                                   2.32E-02
                                      0.5
                                   1.64E-04
                                     99.3
                                     99.3
Nickel
                                     0.35
                                   1.08E-04
                                     0.08
                                   2.52E-05
                                     77.1
                                     76.7
Cadmium
                                     1.28
                                   3.90E-04
                                     0.21
                                   7.00E-05
                                     83.6
                                     82.1

        WESP Metals Reduction Efficiency - November, 2010 Test Results

                              Inlet Concentration
                                  Inlet Load
                             Outlet Concentration
                             Outlet Emission Rate
                             Reduction Efficiency
                             Reduction Efficiency

                                   (ug/dscm)
                                  (lbs.hour)
                                   (ug/dscm)
                                  (lbs/hour)
                           (%, Concentration Basis)
                              (%, lbs/hour Basis)
Arsenic
                                      101
                                   3.06E-02
                                     1.16
                                   3.70E-04
                                     98.9
                                     98.8
Lead
                                      416
                                   1.26E-01
                                     1.45
                                   4.60E-04
                                     99.7
                                     99.6
Nickel
                                     15.3
                                   4.64E-03
                                     0.26
                                   8.34E-05
                                     98.3
                                     98.2
Cadmium
                                     2.18
                                   6.64E-04
                                     0.44
                                   1.38E-04
                                     79.8
                                     79.2

There is a noticeable difference between the outlet emission rates observed during the 2008 test as compared to the results observed during the 2009 and 2010 tests.  This difference is based upon lessons learned during the 2008 test on how to best perform the test methods given the superior performance of the WESP.  The detection limits established for the 2008 test program were designed based on engineering estimates of outlet emission rates for several metals, notably Arsenic and Lead.  The 2008 metals tests, which were performed in triplicate, each lasted approximately six hours.  The 2008 test results demonstrated that the initial metals detection limits were not low enough to establish the true control effectiveness of the WESP.  In response to this enhanced knowledge, the duration of the 2009 and 2010 metals tests was increased from six hours to ten hours and lower detection limits were established.  As a result, the 2009 and 2010 test results represent the best available assessment of the performance of the WESP.
The attached emissions data has redacted from it those items considered confidential by Quemetco and the SCAQMD.  However, as is well known, SCAQMD does not issue or allow an operating permit for through puts greater than that used while stack testing to show compliance.  Furthermore, it is Quemetco's policy to stack test at or above current operating permit limits while maintaining compliance with all permit conditions.  Found at Section H page 29 of the permit:

However, based on the testing through 2010, Quemetco is gathering the data to file for an increase in the permit limit.  This current limit was established pre-WESP and no longer has a valid basis.   At  600 tons/day for 365 days per year the annual quantity is 219,000 tons with process lead emissions in the range of 9 pounds/year and fugitives in the range of 16 pounds /year, the facility annual lead emissions are  0.0000057% of material processed annually.
Misrepresentation by others:   Quemetco's WESP technology was not developed to control fugitive emissions and has not ever been advocated as a control for fugitives.  In an attempt to overstate the cost of the WESP technology, others have presented theoretical WESP cost information based on control of fugitive sources, large volumes of air that do not exhibit  process emission characteristics, and EPA efficiencies and associated costs which are biased towards control of boiler "fly ash" and the use of ESP/WESP's for primary control  (see COMPREHENSIVE EVALUATION OF AIR QUALITY CONTROL TECHNOLOGIES USED FOR LEAD-ACID BATTERY RECYCLING ;Final Report ;TCEQ Contract No. 582-11-99776).
Quemetco has been very clear about the use of the WESP technology as a polishing control after current high efficiency controls on process emissions.  Quemetco is aware of several comments questioning the effectiveness of the technology on varying particle sizes.  Quemetco is at a loss to understand those comments, since almost all papers, text books, and common scientific knowledge concerning electrostatic precipitation plainly make it clear that control efficiency depends on the design parameters.   Even the EPA Air Pollution Training Institute Classroom  -  SI 412B Electrostatic Precipitator Plan Review (FEB 1998) notes this fact.  It should be noted that this EPA publication does have the basics of electrostatic precipitating, but those basics are biased by the fact that most of the comparative information and some general rules of thumb come from controlling boiler "fly ash" and using the "ESP/WESP" for primary control.  None of those biases apply to Quemetco's Polishing WESP.  Quemetco has made this point several times and will continue to do so.  
Related to these comments are some other misconceptions.  Some commenters have stated that Quemetco's polishing WESP is designed to only work on condensables.  That misconception is further extended by indicating control of condensables is needed because of electric furnace emissions.  The fact is that electric furnace emissions go through a high efficiency baghouse followed by a high efficiency scrubber before making it to the WESP.  This theory advanced by others suggesting that Quemetco's post-baghouse, post-scrubber particles are somehow different from particles generated by other secondary smelters  makes no sense to Quemetco, i.e., it simply does not happen the way these commenters suggest. There are not more smaller particles generated by the electric furnace scrubber due to temperature profile differences than by other well controlled furnaces, necessitating use of the WESP.  
There is no technical reason that Quemetco can identify that would make a well designed polishing WESP not appropriate for any current typically controlled secondary lead industry process emission.  Those reasons we have seen put forward indicating a technical non-feasibility do not standup under proper scientific review.   This includes some of the SCAQMD staff who have all the data and know it works, but understandably see the need for further review because this is a first time event with little comparative background in their files.   The reason people are having problems understanding is that they are biased by the bulk of publications concerning WESP being slanted to fly ash removal and as a primary control device.  If one strips away this bias and applies the scientific WESP concepts to secondary lead emissions of Arsenic, Lead and Nickel, the process lead emissions can be reduced from around 615 pounds lead per year to within range of 9 pounds lead per year. 
The conjunction of Quemetco's process controls and fugitive controls puts annual lead emissions from the facility in the range of 25 pounds per year, helps assure on property and off property ambient air type monitoring results in compliance with the Pb NAAQS of 0.15 ug/m^3, and hazard risk model results predict minimal impact from the facility. 
The polishing WESP for process emissions is applicable to all secondary lead smelters which have existing proper controls.   The input to this polishing device would be similar in all cases, i.e., it is the result of passing the processes gases through baghouses and/or scrubbers.  Thus, particle size, gases, and source of the emission are attenuated to uniformity, i.e., secondary lead process emissions after typical proper controls are for practical engineering purposes the same.   Presently, a second generation of the polishing WESP is being installed Quemetco's Indianapolis, Indiana facility and a third generation is planned for Revere Smelting & Refining Corporation in Middletown, New York. 
Finally, EPA's own historical test data indicate that control of both filterable and condensable particulate is necessary.  As noted in a recent (2011) report with reference to a 1992 EPA report:
      COMPREHENSIVE EVALUATION OF AIR QUALITY CONTROL TECHNOLOGIES USED FOR LEAD-ACID BATTERY RECYCLING ;Final Report ;TCEQ Contract No. 582-11-99776 ;Work Order No. 582-11-99776-FY11-07 ;Prepared by: Eastern Research Group, Inc. ,1600 Perimeter Park Drive, Suite 200,Morrisville, NC 27560 ; Prepared for: Brian Foster ,Air Quality Division, Texas Commission on Environmental Quality; April 21, 2011

      "Previous tests conducted at secondary lead smelting facilities indicated that an average of 48% of the particles were filterable particulate, 37% were condensable inorganic, and 15% were condensable organic particles. 4 "

The point of a condensing small particle collector is clearly made in that only 48% of secondary lead particles are filterable particulate.  A full 37% are condensable inorganic and 15% are condensable organic.  The Polishing WESP has designed characteristics which provide effective control of the 52% of particulate that is not filterable.  This EPA testing report clearly demonstrates the necessity to address both filterable and condensable particulates when considering the best available or maximum achievable control technologies for the secondary lead smelting industry.

                                       
                                       
                                       
                                  APPENDIX A
                                       
                                       
                             REQUEST FOR PROPOSAL

On behalf of its subsidiary Quemetco, Inc., RSR  Corporation is requesting proposals  for:   (1) design, (2) fabrication, and/or (3) installation  of an air pollution control device or devices which would lower the combined arsenic emissions of the four stacks  described in the attached "emissions data" and "process schematic" by at least one order of magnitude.

Quemetco, Inc. is a lead recycling facility located in City of Industry, California at 720 South Seventh Avenue.  The major raw material for the facility is the used automobile lead-acid battery.  The major processing steps are separating non-lead bearing materials from lead bearing materials, smelting lead bearing materials, refining & alloying lead to customer specifications, and casting lead ingots to customer specifications.

Emissions are presently highly controlled, however, Quemetco desires to significantly lower the existing emissions.  Reduction in arsenic emissions have only been selected as a surrogate for reduction in all or most of the parameters listed in the attached "emissions data".  Thus, proposals must indicate expected percent reduction for each parameter of emissions data.  A secondary desire is to eliminate water vapor plume.  

Current reviews of technical literature have lead Quemetco and RSR to believe that Wet Electrostatic Precipitation is the technology necessary to achieve its desires.  However, proposals may include other technologies capable of the desired reduction in emissions.  

Proposals are expected on or before Thursday  March 27, 2003.  If  you have any questions, please do not hesitate in contacting Homer Hine at :  Phone: 214-583-316;   FAX: 214-688-5954; e-mail: hhine@rsrcorp.com;

Homer Hine
Vice President
RSR Corporation
2777 Stemmons Freeway
Suite 1800
Dallas, Texas  75207