From: HANSEN Lars [mailto:lars.hansen@fivesgroup.co m]

Sent: Tuesday, July 02, 2013 4:22 PM To: Holloway, Thomas C. (Tom) Subject: RE: Question regarding use of fabric filte rs for brick kilns

Dear Mr. Holloway,

Thank you for your inquiry. We are pleased to resp ond as follows:

As you know, fabric filter baghouses effectively co ntrol particulate emissions. The capture mechanism is primarily the dust cake, which typically consists o f process dust and a pre-coat that is applied prior to introduction of process gases in the case of felted fabrics. Pre-coating is not necessarily required with membrane-coated fabrics, however the process dust c ake is still required to meet the required performance and to ensure a reasonable bag life.

We agree that for applications with very little pro cess dust, the lack of a dust cake would negatively impact total outlet emissions. However, I have to wonder: if there is a lack of process dust from th e kiln, why require a baghouse dust collector?

One additional consideration regarding the dust cak e on the bags: it serves an important function for acid gas neutralization. The cake, when consisting of partially unreacted reagent, acts as a second scrubbing stage, contributing significantly to the system’s overall capture of acid gases.

Selection of fabric is critical to achieve a reason able bag life and uninterrupted compliance. Choice s for high temperature applications are limited to fiberg lass with an upper temperature limit of 500o F; however fiberglass degrades rapidly in the presence of HF acid gas. Pure Teflon fabric also has a lim it of 500o F and is impervious to most acid gases but car ries a very significant price premium.

Aramid, Ryton and P-84 fabrics are generally limite d to 400o F operation but these fabrics are sensiti ve to degradation not only by the acid gases but also due to the relatively high oxygen concentration in brick kiln gases.

We trust this information meets your requirements.

Best wishes,

Lars

Lars HANSEN

SALES DIRECTOR - MINERALS Solios Environment Corp.

6860 S. Yosemite Ct., Suite 2204 Centennial, CO 80112 USA

303-713-0222 - office

303-808-5838 - mobileQuestion regarding use of fabric filters for brick kilns

Holloway, Thomas C. (Tom) [tcholloway@rti.org] Wed 6/26/2013 11:00 AM

I work for RTI International, a nonprofit research institute, and we are providing technical support t o the U.S. Environmental Protection Agency (EPA) to devel op new hazardous air pollutant regulations for the brick manufacturing industry.

I understand that Solios Environment is a supplier of emission control systems such as dry scrubbers a nd fabric filters for acid gas and particulate control , and I have a question I was hoping you could help me answer regarding the applicability of stand-alone f abric filters for controlling emissions from brick kilns. Brick kilns are typically controlled one of three w ays: dry lime injection followed by a fabric filter , dry limestone adsorber, or dry lime scrubber followed b y a fabric filter.

EPA is trying to determine whether it would be feas ible for a brick plant to install just a stand-alon e fabric filter in those cases where the plant is alr eady expected to meet acid gas (HF, HCl) emission l imits. The brick industry has noted that this adaptation o f the technology is not demonstrated by any existin g kilns, so it is unclear what the performance would be.

The industry is concerned that without the dry lime injection that reduces the acid gas, there wouldn’ t be enough particulates in the kiln exhaust to coat the bags and get good performance from the fabric filter. They are also concerned that the uncontroll ed acid in the exhaust stream could rot the bags. There are also concerns about the exhaust gas tempe ratures from brick kilns being too high (nearly 400 F on average, as high as 668F) and the use of membran e bags on low inlet loadings.

We wanted to ask about the validity of these concer ns and whether a stand-alone fabric filter would be feasible for the brick industry.

Any assistance you could provide in this regard wou ld be greatly appreciated. Thanks.

Thomas C. Holloway

RTI International 3040 Cornwallis Rd., P.O. Box 12194 Research Triangle Park, NC 27709 Phone: (919) 316-3733 Fax: (919) 541-7155 E-mail: tcholloway@rti.org