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From: Charles D. Johnson [ mailto:cdjohnson@aluminum.org ]

Sent: Wednesday, July 09, 2014 10:50 AM

To: Putney, David; Curt Wells; 'Palazzolo, Michael A.' Subject: Secondary potline emissions from primary aluminum production facilities

David –

Mike, Curt and I put our heads together earlier thi s week on your questions below and Mike briefed us on the information that he had already shared with you via phone. That information plus our additional though ts are recapped below in italics as responses to your bullet list of questions.

Please feel free to contact me if you have question s regarding this information.

Chuck

1. Is it possible or feasible to install wet roof scru bbers (such as those currently installed at the Int alco facility) on the existing prebake potlines? That is , are there constraints at the existing prebake fac ilities that would make it impossible to install similar we t roof scrubbers?

Inquiries within the industry indicated that this w ould generally be infeasible or impracticable due to the limits of additional weight loads that would be required o n existing potline buildings. While new potline buil dings could be designed for these loads, existing buildi ngs would need to be structurally modified, or separ ate
structures would need to be constructed over the ex isting buildings to support the weight of the wet roof scr ubbers.

2. If wet roof scrubbers could be installed on the exi sting prebake potlines, what capital and annualized costs would you expect for such retrofits (perhaps quick calculations based on historical costs at the Intal co facility could provide a rough estimate)?

Cost estimates were formulated for wet SO2 scrubbin g (not for PM) of primary potline emissions in the design phase of an international aluminum smelter project. Scaling that information based on design potroom roof airflows and2

infrastructure costs yielded a per potline capital cost estimate of $200-$300 million.

3. Does industry have any information as to what fract ion of potline secondary particulate matter (PM) emissions are expected to be PM2.5 as opposed to PM ? If so, what is the source of the estimate (e.g., testing, engineering judgement, etc.)?

Limited test data available indicates that approxim ately 50% of potline roof vent PM emissions were PM 2.5. This data was collected using the previous version of Me thod 202 for condensable PM. With the revised Method 202, we expect that the percentage of PM measured as PM2.5 would

be lower.

4. Does industry have any information as to what fract ion of potline secondary metals emissions are expected to be PM2.5 as opposed to PM? That is, do you have any reason to believe that the metals (especially nickel) would be distributed any differ ently than the “other” particulate matter? Again, i f so, what is the source of the estimate (e.g., testing, engineering judgement, literature review, etc.)?

We have no reason to believe that nickel would be distributed differently than “other” particulate ma tter in general.

5. Does industry have any information (perhaps from hi storical testing at Intalco) as to the control effi ciency, both for PM2.5 and for PM, expected from such wet r oof scrubbers?

The scrubbers at Intalco were installed and optimiz ed for Fluoride control, rather than PM. As a rough estim ate, PM control efficiency is estimated to be on the order of 15% to 30%. However, we have requested Intalco to dete rmine whether any measurement data are available to confi rm this
estimate.

From: Putney, David [ mailto:putney.david@epa.gov ]
Sent: Friday, June 20, 2014 9:45 AM
To: Charles D. Johnson; Curt Wells; Michael A. Palazzo lo Subject: Secondary potline emissions from primary aluminum production facilities

Hello Chuck/Curt/Mike,

Again I am reaching out to The Aluminum Association and the technical subcommittee for input and information on primary3

aluminum production facilities. That is, I am solic iting information regarding potline secondary emissions a nd possible controls thereof – especially in prebake t ype facilities. Specifically, I have the following ques tions for you:

• Is it possible or feasible to install wet roof scru bbers (such as those currently installed at the Int alco facility) on the existing prebake potlines? That is , are there constraints at the existing prebake fac ilities that would make it impossible to install similar we t roof scrubbers?

• If wet roof scrubbers could be installed on the exi sting prebake potlines, what capital and annualized costs would you expect for such retrofits (perhaps quick calculations based on historical costs at the Intalco facility could provide a rough estimate)?

• Does industry have any information as to what fract ion of potline secondary particulate matter (PM) emissions are expected to be PM2.5 as opposed to PM ? If so, what is the source of the estimate (e.g., testing, engineering judgement, etc.)?

• Does industry have any information as to what fract ion of potline secondary metals emissions are expected to be PM2.5 as opposed to PM? That is, do you have any reason to believe that the metals (especially nickel) would be distributed any differ ently than the “other” particulate matter? Again, i f so, what is the source of the estimate (e.g., testi ng, engineering judgement, literature review, etc.) ?

• Does industry have any information (perhaps from hi storical testing at Intalco) as to the control efficiency, both for PM2.5 and for PM, expected fro m such wet roof scrubbers?

Sorry to impose on you (again), but I’m hoping that you may have information that I do not have at this point. As always, please feel free to contact me if you need clarification of my information request or if you h ave any questions or comments.

Thanks,

David Putney, Environmental Engineer U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Sector Policies and Programs Division 109 T.W. Alexander Drive, RTP, NC 27711 Mail Drop D243-02 Ph: (919) 541-2016 Fax: (919) 541-3207
Email: putney.david@epa.gov