10/26/2011

Steffan Johnson

Phone notes and email conversations regarding the use of caustic scrubbers to capture chromium 

emissions from wool fiberglass facilities.

The following are email exchanges with Lars Hansen at Hansen Engineering regarding scrubber design, 

effectiveness, and cost.

09/08/2011

Lars,

Thank you for your reply, that was very helpful.

I will contact you if more questions arise.

Best regards,

Stef 

From: larshansen2005@comcast.net

To: Steffan Johnson/RTP/USEPA/US@EPA

Cc: HANSENENG <hanseneng@wildblue.net>

Date: 09/08/2011 08:55 AM

Subject: Re: Scrubber design question

Steffan,

Answers in the text

Best regards,

Lars
From: "Johnson Steffan" <Johnson.Steffan@epamail.epa.gov>

To: larshansen2005@comcast.net

Sent: Tuesday, September 6, 2011 1:17:56 PM

Subject: Re: Fwd: Scrubber design question

Mr. Hansen,

Thank you, once more, for your assistance with the information you have provided below.

I am wondering if your group has installations of similar devices on sources where the same temperature 

and/or capture technique are being utilized?

We are a small company and over the years have downsized from 40 to now 7 

people.

I have spent many years as a metallurgist in the steel, alloy, stainless, super 

alloys,

pure Ni, Mn, Zr, Ti and automotive industry ( heat treating) and since 1974 

working as Hansen 

Engineering with Iron oxide dust , calcining metal residual waste ( Ni, 

Cu,W,Mo,Ta,Si,V,Re,Fe,Co) up to 2800 F,

Pollution wise with Dust , SOx, NOx, HCl, F, acidics of W,Mo,V.

I have experience in plating and its pollution problems.

As Hansen Engineering , we have our own calcining unit with a venture entrance 

temperature of 350 to 500 F 

We designed a large Acid regeneration plant for Essar Steel in Pune India, in 

operation since 2006.

Had a smaller unit in Toledo Ohio for 6 years in operation. Both dealing with 

venture entrance temperature of 

400 to 500 F . The Toledo, Ohio unit was built with two EPA grants.

Was a consultant for various Acid regeneration plants, pickling lines in the USA, 

Taiwan, Mexico and still for 

USS Posco in Pittsburgh California

We designed a 250,000 T/y shallow high speed pickling line for Steel coils for ISP 

Pottstown, Pa

Was for nearly 6 years plant supt at MolyCorp Washington Pa dealing with a large 

roaster with temperatures of 1400 F

in the cyclones, 1000F baghouse, 600F venture, ESP's Packed towers , Oxidizing 

towers.

We have upto date experience with Cyclones , baghouses ( high Temps), 

ventures, Packed towers, Condensate units

and Stack monitoring for HCl, SO2, Nox,

We refurbished scrubbers, ventures, pickling lines for the steel, paper and 

refineries using our special high temperature FRP compound good up to 600 F 

constant and for 1/2 hr at 1400 F and allows instant repairs.

Experiences in the Specialty metallurgical installations such as Scrap preheating, 

all sort of steel furnaces,

galvanizing operations, heat treating furnaces, annealing furnaces, etc.
But again I like to emphasize that a certain amount of experimenting for 

scrubbing out elements can not be avoided.

The trick is to minimize the amount of uncertainty and get close enough to refine 

the process.

I have experience in the metallurgy, chemistry, Mechanical Engineering.

I am a registered PE in Pa, De, and Ontario.

Hope the above will give you some idea of my experiences.

Perhaps glass furnaces, or specialty metallurgical installations?

We are hoping to be able to justify requiring these devices for control based on a "Technology Transfer" 

statement ("It works in other industry types and should work here").

Thank you again, for your assistance.

Sincerely,

Stef Johnson

Steffan Johnson

EPA/OAQPS/SPPD

Measurement Policy Group

109 T.W. Alexander Drive D-243-05

Research Triangle Park, NC 27713

Phone: 919 541 4790

email: johnson.steffan@epa.gov

From: larshansen2005@comcast.net

To: Steffan Johnson/RTP/USEPA/US@EPA

Cc: HANSENENG <hanseneng@wildblue.net>

Date: 07/10/2011 09:13 PM

Subject: Fwd: Scrubber design question

Steffan, 

I can assume that either an exhaust fan drives the airflow through the ESP 

or pulls it through the ESP at 40,000 cfm at about 10 to 15 inches WC 

Thus an exhaust fan is not required for our package. 

 

The unit will be rated for 45,000 cfm 15 " wc 

 

The unit and all the internal packing, grating and compression/expansion disc 

will be made of our RB20 high temperature poly ester vinyl compound good 
to 650 F operation conditions. 

 

The tower packing will be 1.5 ,1" rings and half 1" rings and the rings have a porous 

surface. The sections will be separated by grating and compression/expansion discs 

A total surface spay bar system for the recycling of 250 gal/min with a 20 hp HD PE 

lined pump, included a PH controller connected to 30 % caustic supply. 

A density meter to automatic discharge when the selected density is reached to a 

selected discharge location 

The unit we propose is 8' ID x 20' high with a short 8 ft x 36" ID stack.Test holes on top 

and 

bottom The bottom of the unit has a 5 ' high x 8' ID sump with level controller and 

automatic discharge, The flanged 24" entrance wil on a 90 deg blow onto the sump 

surface. Each section will have a fill ( top) and drop out ( bottom) 8"ID flanged opening. 

The top spray bar section are individual flanged removable spraybars for cleaning, 

the spray bars are connected to two headers which in turn are connected to a single 

header 

towards the recirculation pump. 

The removable Stack has a 4 ft final 1" RB 20 tower rings ( removable) supported on 

top and bottom by grating. 

We believe that a 90 to 95 % Cr removal is posible maybe higher, but we can not give 

quanrantee. It would be from our standpoint, experimental. 

Total package cost about $ 210,000.00 with a 4 to 5 month delivery.

Best regards, 

Lars Hansen, PE 

 

From: Steffan Johnson <Johnson.Steffan@epamail.epa.gov>

Date: Fri, Jul 8, 2011 at 10:38 AM

Subject: Re: Scrubber design question

To: LARS HANSEN <hanseneng@wildblue.net>

Lars,

Thank you for your reply. 

First, some background. I work for the US EPA, in the Sector Policy Programs Division. We have an 

industry sector with a need for this sort of control and we are trying to determine if the controls are 

feasible and of reasonable economic impact to the affected facility.

I have spoken with other scrubber manufacturers regarding chromium, but they are designed for chrome 

plating control which handles ambient temperature. It would appear that your material could sustain the 

temperatures that we would expect to see from the ESP outlet, so from that standpoint it seems that a 

design using this material would be feasible.

I am not a scrubber design expert, and I am not looking for a fully engineered product, but rather only 

looking to see if such controls are available and at what approximate cost.
I would think pH control would be necessary to maintain a caustic solution in the scrubber greater than pH 

8.5. I also believe 49% NaOH is readily available for this purpose. Consider that much of the NaOH 

would also be consumed by CO2 in the gas stream. 

ESP particulate grain loading is expected to be quite low, less than 0.05 gr/dscf. There is no regulatory 

requirement at this time to reduce particulate emissions further unless that is included in the effort to 

control the chromium (the target pollutant).

Chromium emissions are on the order of 0.2 ppmv or .02 mg/m3. 

Flow is expected to be 35 - 40 thousand cubic feet per minute, dry, standard.

So what I need to know is:

What sort of control efficiency could be obtained? 99.5%? 99.95%? 

And what would be the approximate cost of such a scrubber system (including a fan to power the flow)

Thanks much,

Stef 

Steffan Johnson

EPA/OAQPS/SPPD

Measurement Policy Group

109 T.W. Alexander Drive D-243-05

Research Triangle Park, NC 27713

Phone: 919 541 4790

email: johnson.steffan@epa.gov

"Always be yourself. Everyone else is already taken." - Oscar Wilde

From: LARS HANSEN <hanseneng@wildblue.net>

To: Steffan Johnson/RTP/USEPA/US@EPA

Cc: larshansen2005@comcast.net

Date: 07/06/2011 10:12 PM

Subject: Re: Scrubber design question

Stef, 

Our special plastic RB20 is a Poly Vinyl Ester compounded to make it acid and caustic 

prove and able to take 

from - 100 F up to + 600 F constant and 1400 F for about 1/2 hr.. Can be fabricated into 

any size.Including 

tower packing half rings. Good for venture and packed tower scrubbers. 

I what form is the Chromium , oxide , metal , combination. What typical particle size and 

at what concentration % 
or ppm. 

What strengths caustic you envision at 475 F ? 

What is the cfm gas or fume flow and at what psi or " wc 

What does your the environmental permit allows 

Have you looked at a bag house approach next a venture and then the EPS unit 

followed be an caustic scrubber? 

Lars Hansen 

 

On Wed, Jul 6, 2011 at 6:56 AM, Steffan Johnson 

<Johnson.Steffan@epamail.epa.gov> wrote: 

Greetings,

I am looking for a scrubbing solution for an industry sector.

The situation is a furnace which exhausts through a dry ESP for particulate control. Temperature at the 

ESP outlet is ~475 deg. F.

Flow rate is measured in the range of 35-40k SCFM

The need is to control chromium emissions from the outlet of the furnace/ESP. Typically this would be 

done with a caustic scrubber, however because of the temperature and flow rate many scrubber 

manufacturers who typically handle chromium scrubbing (chrome plating) do not have designs that can 

handle scrubbing in this range. I found your site on the internet and thought I would see if your group 

could produce such a unit (packed tower is what I was thinking but you are the experts...). 

Current chromium emissions average 0.5 lb/hr. We'd like to reduce that by 99% or greater. 

If your company could manufacture such a scrubber, please let us know and also what the cost to 

produce/install might be (very rough guess is fine, we don't need design details).

Thanks much for your help!

Best regards,

Stef Johnson

Steffan Johnson

EPA/OAQPS/SPPD

Measurement Policy Group

109 T.W. Alexander Drive D-243-05

Research Triangle Park, NC 27713

Phone: 919 541 4790

email: johnson.steffan@epa.gov

========================================
The following is an email to Eamonn Shanahan at Industrial Air Solutions. I received no reply to two 

attempts.

07/14/2011

Greetings Eamonn,

Any thoughts on this would be much appreciated. Thank you for your time.

Stef 

===========================================

06/28/2011

Hi Eamonn,

I have an industry with a need to scrub chromium emissions. 

Source has an ESP for particulate scrubbing, so particulate grain loading would be expected to be fairly 

low.

Source has ~470 deg. F. stack temp on the ESP outlet. Temp is about 1400 deg. F on the furnace outlet, 

but the ESP section cools things down a bit.

Flow is 38,900 acfm or 18,800 dscfm, but may be higher as the test data I am looking over involves only 1 

of 2 furnaces exhausting to the same ESP. So consider that the flow rate is likely double. Temp. should 

be about the same.

Again, the issue is chromium scrubbing, so I am thinking a caustic scrubber would be in order, either KOH 

or NaOH reagent seems like a good place to start. 

The emissions from the source are high, on the order of 0.05 lbs/hr chromium. Capture efficiency sought 

would be on the order of 99.95 to 99.99%.

We're just looking to see if such technology exists, or could be readily designed/built should a facility need 

to order one.

Thanks much for your assistance.

Stef 

From: "Eamonn Shanahan" <eshanahan@industrialairsolutions.com>

To: Steffan Johnson/RTP/USEPA/US@EPA

Date: 06/28/2011 02:27 PM

Subject: Scrubber

Regards,

Éamonn Shanahan
Industrial Air Solutions, Inc.

6212-A Westgate Road

Raleigh, NC 27617

Toll-Free 877-844-3293 ex:232

Cell: 919-200-2926

Fax: 877-747-3545 

6/28/2011

Phone conversation with Eamonn Shanahan at Industrial Air Solutions. He asked for my email address, 

which I provided, so he could send me an email and I would reply with details of the scrubbing needs. I 

replied immediately, but received no response.

09/19/2011

Conversation with Art at KCH 

144 Industrial Drive

Forest City, North Carolina 28043

(828) 245-9836

art@kchservices..com

Art tells me that the gas stream would need to be quenched to below 160 deg. F so that his company 

could employ a fiberglass/PVC scrubber. The quench chamber would be a water spray tower, prior to a 

more traditional chromium scrubber that would use composite mesh pads as the scrubbers for chromium 

electroplating industry uses. These are very efficient at chromium removal, according to Art.

Art said the device could be made from stainless steel but at a substantial cost increase. He did not give 

me a cost estimate for the unit.

From Duall/Metpro on September 20, 2011

Good Morning again SteffanMy apologies....apparently I did not offer enough explanation.

Yes, we know that your request was looking for a wet caustic scrubber to deal with the exhaust from the 

existing dry ESP that is 20,000-30,000 CFM at 400 oF at 4% moisture content and contains 0.05 ppm of 

chromium. If the ESP is discharging this high of concentration of chromium, then it must be in a submicron form. With this in mind, a pre-quenched gas stream to reduce the temperature, along with a 

wet packed bed scrubber utilizing a recirculated solution of caustic is NOT capable of addressing and 
removing sub-micron chromium. Even our Hexmaster equipment, which is used for chrome plating 

applications, can’t address this sub-micron chromium, since it is designed to remove 2 micron and 

larger. 

In short, Met-Pro Environmental Air Solutions currently does not have a product/technology that 

addresses sub-micron particles.

We hope this information better answers or addresses your question. Please let us know if you should 

have any other questions.

Have a great day,

Arlene Miller

Regional Sales Manager

Met-Pro Environmental Air Solutions

Tel: 989-725-8184 

Cell: 330-208-6384

Fax: 989-725-8188

www.met-pro.com

" Protecting the environment through the combined resources and technologies of the Duall, FlexKleen, BioReaction and Systems brands "

** Please note that Duall is now part of the Met-Pro Environmental Solutions group.

We have also established the Met-Pro Industrial Services team to provide our customers 

with more comprehensive installation, maintenance, and field service capabilities. 

Please contact us or our local representativefor additional information.

From: Johnson.Steffan@epamail.epa.gov [mailto:Johnson.Steffan@epamail.epa.gov] 

Sent: Tuesday, September 20, 2011 10:07 AM

To: Arlene Miller

Subject: RE: FW: Scrubber application question
Arlene,

I am afraid I may have confused you somewhere along the way.

I am looking for chromium capture POST dry ESP. (a dry ESP is already in place).

Would you have any ideas for additional controls for chromium capture?

Thank you,

Stef 

From: Arlene Miller <amiller@MET-PRO.com>

To: Steffan Johnson/RTP/USEPA/US@EPA

Cc: Arlene Miller <amiller@MET-PRO.com>

Date: 09/20/2011 10:04 AM

Subject: RE: FW: Scrubber application question

Good Morning SteffanAfter reviewing this application with a few of our senior engineering, as I am sure you are aware, a wet or dry ESP 

is the recommended technology for glass furnace applications. Unfortunately, that is a technology that we 

currently do not offer as part of our Met-Pro Environmental Air Solutions brands. We also looked at the 

technologies that we do have available and again, unfortunately, we do not have a product that would address 

your earlier points below.

We would like to thank you for considering Met-Pro Environmental Air Solutions for this project and please think 

of us again for your future air pollution control designs.

Best wishes on your project and have a great day,

Arlene Miller

Regional Sales Manager

Met-Pro Environmental Air Solutions
Tel: 989-725-8184 

Cell: 330-208-6384

Fax: 989-725-8188

www.met-pro.com

" Protecting the environment through the combined resources and technologies of the Duall, Flex-Kleen, 

BioReaction and Systems brands "

** Please note that Duall is now part of the Met-Pro Environmental Solutions group.

We have also established the Met-Pro Industrial Services team to provide our customers 

with more comprehensive installation, maintenance, and field service capabilities. 

Please contact us or our local representativefor additional information.

From: Johnson.Steffan@epamail.epa.gov [mailto:Johnson.Steffan@epamail.epa.gov] 

Sent: Tuesday, September 20, 2011 7:25 AM

To: Arlene Miller

Subject: Re: FW: Scrubber application question

Good morning Arlene,

Thank you for your response, time is growing short for us to get this information. I am hoping you can 

respond to this early today? 

The industry sector is Wool Fiberglass, specifically the glass melt furnace. 

These sources use dry ESP's for particulate control, but recently they have begun using a high chrome 

refractory brick and, in some instances, this is causing elevated chromium emissions on the ESP outlet. 

Temps on the ESP outlets are typically 400 deg. F. Flow for a single furnace on the order of 20,000 acfm 

to 30,000 acfm. Moisture is relatively low, about 4% (depends a bit on fuel for the furnace) and 

particulate grain loading on ESP outlet is less than 0.05 gr/dscf. 

The real need is to control the chromium emissions, which are currently on the order of 0.05 ppmv. Low, 

yes, but in terms of tons/year this can be a significant figure.

We are considering developing a chromium standard for this industry (about 30 furnaces) and are looking 

for references to control technologies that would be applicable. 

I need to hear back from you about the feasibility of a scrubber (caustic?) that would meets 90-95% 

capture of the chromium and I also need to know if you have success with such controls on other, similar 

industry types or sectors.

Thanks very much, please call if you have more questions.

Sincerely,

Steffan Johnson
EPA/OAQPS/SPPD

Measurement Policy Group

109 T.W. Alexander Drive D-243-05

Research Triangle Park, NC 27713

Phone: 919 541 4790

email: johnson.steffan@epa.gov

From: Arlene Miller <amiller@MET-PRO.com>

To: Steffan Johnson/RTP/USEPA/US@EPA

Cc: Arlene Miller <amiller@MET-PRO.com>

Date: 09/19/2011 01:32 PM

Subject: FW: Scrubber application question

Good Afternoon SteffanThank you for your request below through our website.

We have experience with many different types of industries, such as chrome plating to heat treatment chemical 

baths. Your e-mail below did not exactly define what type of industry or process requires the chromium control 

and 400 oF caustic control.

Met-Pro Environmental Air Solutions is comprised of not only our Duall Brand of wet packed bed scrubbers, but 

also bioscrubbers, Flex-Kleen baghouses and our Systems group’s regerenative, catalytic or direct fired thermal 

oxidizers, so we have experience dealing with high temperature applications.

We would be happy to review your application further, but we will need to discuss the following items in greater 

details:

1) Based on an existing dry ESP currently in operation, what is the dry ESP currently operating at that you are 

not satisfied with its performance?

2) What are the particulars of the inlet process gas stream, i.e., inlet gas flow rate, inlet gas temperature, inlet 

moisture content, inlet contaminates, previous inlet testing data (if available), required removal efficiency 

performance, etc.?

This may be easier to discuss on the phone, so please let me know what time works best for you to discuss.

Looking forward to hearing from you,

Arlene Miller

Regional Sales Manager

Met-Pro Environmental Air Solutions

Tel: 989-725-8184 
Cell: 330-208-6384

Fax: 989-725-8188

www.met-pro.com

" Protecting the environment through the combined resources and technologies of the Duall, Flex-Kleen, 

BioReaction and Systems brands "

** Please note that Duall is now part of the Met-Pro Environmental Solutions group.

We have also established the Met-Pro Industrial Services team to provide our customers 

with more comprehensive installation, maintenance, and field service capabilities. 

Please contact us or our local representativefor additional information.

From: Janel Landes 

Sent: Wednesday, September 14, 2011 4:09 PM

To: Arlene Miller

Subject: FW: Scrubber application question

From: Johnson.Steffan@epamail.epa.gov [mailto:Johnson.Steffan@epamail.epa.gov] 

Sent: Wednesday, September 14, 2011 

To: Janel Landes

Subject: Scrubber application question

Greetings,

I work for the US Environmental Protection Agency, in the Measurement Policy Group of the Office of Air 

Quality Protection and Standards. 

We have an industry sector with an apparent need to control emissions of chromium. I am familiar with 

scrubbing technology used in chrome electroplating industry, however the emissions from this process 

are a bit hotter, on the order of 400 degrees F. 

The source already has a dry ESP for control of particulate, so the scrubbing application would be 

primarily for control of the chromium and I think a caustic (NaOH) scrubber would be appropriate,, though 

there would be some acid gases present that would also "use" some of the caustic. Flow rate at the ESP 

outlet is on the order of 20-30k SCFM.

My question is, do you folks have experience with such scrubbers (I'm thinking packed tower type, but 

you may have a different idea) with caustic control, in an environment that is this hot?

If so, with what industry types? (I'm thinking perhaps specialty metallurgical, iron and steel, or perhaps 

some chemical manufacture?)
Thank you very much for your reply, I appreciate your input. 

Sincerely,

Stef Johnson

Steffan Johnson

EPA/OAQPS/SPPD

Measurement Policy Group

109 T.W. Alexander Drive D-243-05

Research Triangle Park, NC 27713

Phone: 919 541 4790

email: johnson.steffan@epa.gov