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**MEMORANDUM** To: Rochelle Bo yd , U.S. Environmental Protection Agency , OAQPS From: Mark Bahner and David Green , RTI Date: January 4 , 201 2 Subject: D raft T echnology Review for the Secondary Aluminum Production Source Category

**1.0 BACKGROUND**  **1.1 Requirement**  **s of Section 112(d)(6) of the CAA** Section 112 of the CAA requires EPA to establish technology

- based standards for sources of HAP. These standards are often referred to as maximum achievable control technology , or MACT standards. Section 112 also contains provisions requiring EPA to periodicall y revisit these standards. Specifically , paragraph 112(d)(6) states:

(6) REVIEW AND REVISION.

– The Administrator shall review, and revise as necessary (taking into account developments in practices, processes, and co ntrol technologies), emissions standards promulgated under this section no less often than every

8 years. **1.2 Description of the Secondary**  **Aluminum Production**  **Source Category and Requirements of**  **the Current NESHAP** The current National Emissions Standards for Hazardous Air Pollutants (NESHAP) for the Secondary Aluminum Production source category was promulgated on March 2 3, 2000 (6 5 FR 1690 ) as 40 CFR part 63, subpart RRR

. The rule was amended at 67 FR 79814, December, 30, 2002; 69 FR 18803, April 9, 2004; 69 FR 53984, September 3, 2004; 70 FR 75346, October 3, 2005 ; and 70 FR 57517, Dec ember 19, 2005. The NESHAP applies to affected sources of HAP emissions at secondary aluminum production facilities. A secondary aluminum production facility is defined as any

e stablishment using clean charge, aluminum scrap, or dross from aluminum production, as the raw material and performing one or more of the following processes: scrap shredding, scrap drying/delacquering/decoating, thermal chip drying, furnace operations (i. e., melting, holding, sweating, refining, fluxing, or alloying), recovery of aluminum from dross, in

- line fluxing or dross cooling. A secondary aluminum production facility may be independent or part of a primary aluminum production facility . For purposes of the NESHAP, aluminum die casting facilities, foundries and extrusion facilities are not considered to be secondary aluminum production facilities if the only materials they

melt are clean charge, customer returns, or internal scrap, and if they do not o perate sweat furnaces, thermal chip dryers, or scrap dryers/delacquering kilns/decoating kilns.2

T here are 161 secondary aluminum production facilities that are subject to the NESHAP. Emission limits have been promulgated for particulate matter (PM) as a surrogate for metal HAP, total hydrocarbons (THC) as a surrogate for organic HAP other than dioxins and furans (D/F) , dioxins and furans are expressed as toxicity equivalents, and h ydrogen chloride (HCl) as a surrogate for acid gases , including hydrogen fluo ride

. HAP are emitted from the following affected sources: aluminum scrap shredders (regulated for PM), thermal chip dryers (THC and D/F ) , scrap dryers/delacquering kilns/decoating kilns (PM, D/F, HCl and THC ) , sweat furnaces (D/F), dross

- only

furnaces (PM ), rotary

dross coolers (PM), group 1 furnaces (PM, HCl and D/F), and in

- line fluxers (PM and HCl). Group 2 furnaces and certain in

- line fluxers are regulated b y work practices. Control devices currently in use to reduce emissions from affected sources s ubject to the NESHAP include , fabric filters for control of PM from aluminum scrap shredders ; afterburners for control of THC and D/F from thermal chip dryers ; afterburners plus lime

- injected fabric filters for control of PM , HCl, THC and D/F from scrap drye rs/delacquering kilns/decoating kilns ; afterburners for control of D/F from sweat furnaces ; fabric filters for control of PM from dross

- only

furnaces and rotary

dross coolers ; lime

- injected fabric filters for control of PM and HCl from in

- line fluxers ; and lime

- injected fabric filters for control of PM, HCl and D/F from group 1 furnaces. All affected sources with add

- on controls are also subject to design requirements and operating limits to minimize fugitive emissions. **2.0 DEVELOPMENTS IN PRAC**  **TICES, PROCES SES, AND CONTROL**  **TECHNOLOGIES** For the purposes of this technology review, a “development” was considered to be a (n):

 add

- on control technology that was not identified during the development of the current NESHAP for the source category ;  i mprovement to an existing add

- on control technology that could result in significant additional HAP emissions reductions;
 w ork practice or operational procedure that was not identified during development of the current NESHAP for the source category ; or  applicable p ro cess change or pollution prevention alternative that was not identified and considered during the development of the current NESHAP for the source category
. We investigated developments in practices, proce sses and control technologies through a literature review and discussions with industry representatives, and included questions in a Section 114 information collection request (I CR) that was sent to all companies thought to be subject to the NESHAP. The results of these anal yses are presented in the follo wing sections. **2.1 Literature review and industry contacts**  2.1.1. Multichamber Delacquering Kiln/Melting Furnace At least one company supplies multichamber furnaces that combine the functions of a delacquering kiln and a melting furnace. This furnace has th e potential to reduce emissions , because all of the emissions from the delacquering of used beverage cans and other coated scrap3

are swept into another chamber where the delacquered scrap is melt ed

. These emissions are combusted in the melting chamber, red ucing energy

requirements; destroying THC and D/F; and eliminating the need for an afterburner. A multichamber furnace can therefore be used as a replacement for a delacquering/decoating kiln (with afterburner) plus a group 1 furnace handling only clean ch arge, or the multichamber furnace can be used as a replacement for group 1 furnace handling other than clean charge. At least 16 of these furnaces are in operation in Europe, Asia and the M iddle E ast. One furnace of this ty

pe is presently

operating in the U. S. and is permitted as a group 1 furnace handling other than clean charge

. The emissions test data for the one multichamber furnace operating in the U.S. indicate that the furnace does n ot produce lower D/F emissions (in toxic equivalents, or TEQs) than any other group 1 furnace handling other than clean charge, or than any delacquering/decoating kiln. Table 1 lists D/F emissions from the one multichamber furnace (operating at L ogan Aluminum). Table 1 also lists D/F emissions from three group 1 furnaces handling other than clean (i.e., “dirty”) charge, and three delacquering/decoating kilns. The other furnaces and delacquering/decoating kilns in Table 1 w ere selected because they had low reported D/F emissions, and test reports were available to support those reported emissions. The D/F emissions from these other sources are lower than the D/F emissions from the multic hamber furnace, indicating that emissions from the multichamber furnace are not lower than any other group 1 furnace handling other than cle an charge, or any delacquering/decoating kiln. Therefore, based on available information, it is not clear that the multichamber furnace technology would reduce HAP emissions relative to technologies that are already used b y other facilities in the U.S. **Ta ble 1. Comparison of**  **D/F Emissions from a Multichamber**  **Furnace with**  **Other Technologies** 
**RTI ID**  **Facility Nam**  **e Equipment ID**  **Equipment Type**  **Test Date Test**  **- Condition**  **Av erage**  **D/F in ug/Mg TEQ**  **(1)** 351 Logan Aluminum Multichamber

Furnace Grp1 dirty

charge 5/13/2 008 1

- 50%Class I/50% Class III 1.061 (2) 351 Logan Aluminum Multichamber

Furnace Grp1 dirty

charge 5/13/2008 1

- 100% Class I 0.461 351 Logan Aluminum Multichamber

Furnace Grp1 dirty

charge 5/14/2008 2

- 80% UBC’s/20% Class I 0.496 351 Logan Aluminum Multich am ber Furnace Grp1 dirty

charge 8/12/2008 1

- 50%Class I/50% Class III 0.26 421 Alcan Rolled Products DC1M Grp1 dirty charge 1/29

-

31/2008 1 0.023 335 Jupiter Aluminum Furnace 2 Grp1 dirty charge 1/25/2010 1 0.027 211 Alumax Texarkana EPN 011A Grp1 dirty c harge 4/20/2009 1 0.103 198 Novelis P9A Delacquering Kiln 10/01

-

02/2008 1 0.000419 198 Novelis P9B Delacquering Kiln 9/30

-

10/1/2008 1 0.000173 415 JL French P30

- 1 Delacquering Kiln 6/22/2009 1 0.02 (1) Average of three test runs, except where noted. (2) Averag e of two test runs.4

2. 1 .2. Eddy

Current Separators Sweat furnaces are used in the secondary aluminum industry

to separate aluminum from ferrous metals. Certain types of scrap (primarily automotive) are composed of individual pieces of metal , which cont ain both aluminum and iron or steel. Automobile parts such as aluminum engine blocks with cast iron cylinders, aluminum transmission cases with steel gears and inserts and aluminum suspension components with steel inserts are examples of sweat furnace feed

. These materials, often containing oil and grease, are separated b y melting the aluminum from the ferrous metals with higher melting points. The molten aluminum is tapped to form ingots or “sows,” and the ferrous resi due is raked from the furnace. Sweat f urnace emissions contain D/F , which results from the combustion of the organic contaminants in the scrap. Eddy current separators are used to separate a concentrated aluminum fraction from a heterogeneous scrap feed. These units operate at ambient temperature and emit no D/F or other gaseous pollutants. Eddy

current separators are used to separate a concentrated aluminum fraction from a heterogeneous scrap feed. These units operate at ambient temperature and emit no D/F or other gaseous pollutants. They are used on the material output from mechanical shredders that shred automobiles and appliances (not on the aluminum scrap shredders used in the secondary

aluminum industry). These units can potentially decrease the need for sweat furnaces. However, the pro duct of eddy current separators is not an aluminum ingot or sow, as with a sweat furnace. Therefore, the product of eddy current separators must undergo further processing to produce an aluminum ingot or sow , and it is not possible to directly compare eddy current separators with sweat furnaces. 2.1.3 Cataly

tic Filter Bags Cataly tic filtration s ys tems, including catal yt ic filter bags, are available to reduce D/F emissions. These bags incorporate an expanded poly tetrafluoroeth yl ene membrane coated with a precious metal catal ys t , which promotes the oxidation of D/F. The manufacturer claims that this sy stem is installed in over 100 applications around the world, including at least one secondary aluminum processing plant. To determine the extent that these ba gs are in use in the secondary aluminum industry

in the U. S., a question was included in an information collection request ( IC R) sent to all ide ntified secondary aluminum production facilities. The question “ Do you use catal yt ic filters for dioxin control (e.g., http://www.donaldson.com/en/industrialair/literature/051754.pdf ) ? ” was answered no or “ not applicable ” by

126 of the 159 facilities that responded. The remaining facil ities did not answer this question. We have insufficient information to conclude that this technology is generall y applicable to secondary

aluminum production facilities, or to estimate the extent of emission reductions that it might achieve.5

**2.2 Responses**  **to ICR** In an attempt to identify

new emission control technologies in use, an IC R was sent to all identified secondary

aluminum production facilities. To identify new technologies the following questions were asked: • Please provide details for any alter native control devices (i.e., control devices other than fabric filters, lime

- coated fabric filters, or afterburners), monitoring (including particulate matter or HCI continuous emissions monitors), or operating conditions at this facility for equipment re gulated under 40 CFR 63, subpart RRR. • Have you injected activated carbon or other typ e of sorbent for HAP control (excluding research efforts)? What barriers do you envision to adding carbon injection to fabric filters for HAP control? • Do you have any plans to install any new higher efficiency

rated control devices or have any pending applications to add on any new controls? 2.2.1 Activated Carbon Injection for D/F Control Three respondents reported using activated carbon injection for control of d ioxin, and one respondent reported using activated carbon injection previously on a unit that has since been shut down. Activated carbon is ty picall y added to control D/F, although in one case it was used with a thermal chip dryer and may also have helped control THC. This technology was known at the time of the development of the current standard and was regarded as a possible control alternative for sources that were unable to demonstrate compliance using lime

- injected fabric filters

. This technology

is s uitable for retrofit to existing fabric filters

. In addition to the cost of the feeder s ys tem and carbon supply , all of the added carbon ultimatel y adds to the ma ss of dust requiring disposal. Carbon injection sy stems in other industries are ty picall y about 80 to 90% efficient at D/F control. 2.2.2 Ammonia In

jection for HCl Control Four respondents reported injecting ammonia into furnace exhaust gas as a means of HCl control. This technology

was unknown at the time of development of the current rule. At l east one of the four respondents plans to replace the lime currently used to control HCl emissions with ammonia. Itis not clear from the IC R responses whether the remaining respondents reporting the use of this technology are replacing lime with ammonia o r adding ammonia i n addition to l ime. The HAP emission reductions achieved from using this technology alone or in addition, to lime injection are also not known. This technology is suitable for retrofit to existing fabric filters

. The applicability of this technology

is unlikely

to be influenced by

furnace configuration because the ammonia is added between the furnace and the fabric filter

. Ithas the potential of decreasing the amount of fabric filter dust requiring disposal, but would likely result in inc reased air emissions of ammonia , which is not a HAP but may be problematic due to nitrogen deposition.6

**3.0 CONCLUSIONS:**  **RECOMMENDED REVISIONS**  **BASED ON DEVELOPMENT S**  **IN PRACTICES, PROCES SES AND CONTROL TECH**  **NOLOGIES** This review identified several developments in practices, processes or control technologies that have been implemented in this source category since promulgation of the current NESHAP. These technologies are not in use by a substantial number of secondary aluminum production facilities in the U. S. One possible reason for this is that facilities are able to meet the current MACT emission limits without using them. In other industries, such as P ortland cement and electric arc steel mills, D/F emission reduction s of 80

- 90 percent have been achieved with the addition of activated carbon injection. In general, existing technologies can be adapted to achieve lower emissions. For example, d ecreased HCl emissions might be achieved by increasing the lime injection rate. Decreased THC emissions might be achieved b y i ncreasing afterburner temperature. If more stringent risk

- based standards are justified, it is likely that either improvements to existing control devices, implementation of new technologies or pollution prevention techniques will be selected on the basis of overall cost and reliability

. None of the newer technologies have supporting test data that justify more stringent technology

- based standard s . The technologies implemented since the development of the current NESHAP may provide a means for decreasing HAP emissions from secondary aluminum production, however there are insufficient data to justify more stringent technology

- based standards for either new or existing sources.