----- Forwarded by Melanie King/RTP/USEPA/US on 08/09/2010 11:16 AM

-----

|------------>

| From: |

|------------>

>---------------------------------------------------------------------------

---------------------------------------------------------------|

|"Bromberg, Kevin L." <kevin.bromberg@sba.gov>

|

>---------------------------------------------------------------------------

---------------------------------------------------------------|

|------------>

| To: |

|------------>

>---------------------------------------------------------------------------

---------------------------------------------------------------|

|"Higgins, Cortney" <Cortney_Higgins@omb.eop.gov>, "Kymn, Christine J."

<Christine_J._Kymn@omb.eop.gov> |

>---------------------------------------------------------------------------

---------------------------------------------------------------|

|------------>

| Cc: |

|------------>

>---------------------------------------------------------------------------

---------------------------------------------------------------|

|"Maresca, Charles A." <Charles.Maresca@sba.gov>, RobertJ

Wayland/RTP/USEPA/US@EPA, Peter Tsirigotis/RTP/USEPA/US@EPA, "Mancini, Dominic

|

|J." <Dominic_J._Mancini@omb.eop.gov>, Melanie King/RTP/USEPA/US@EPA

|

>---------------------------------------------------------------------------

---------------------------------------------------------------|

|------------>

| Date: |

|------------>

>---------------------------------------------------------------------------

---------------------------------------------------------------|

|08/09/2010 09:15 AM

|

>---------------------------------------------------------------------------

---------------------------------------------------------------|

|------------>

| Subject: |

|------------>

>---------------------------------------------------------------------------

---------------------------------------------------------------|

|NSCR Catalyst Will not deliver the 97% NOx reductions as estimated by EPA

for 4SRB Engines |

>---------------------------------------------------------------------------

---------------------------------------------------------------|

Thanks EPA for the reply on Saturday that we’ve reviewed over the weekend, but

the reply only reinforces our previous conclusion that NOx reductions will be

seriously eroded in the field by more than a factor of two. This supports our

key request that 4SRB catalysts not be required for engines between 500 and

705 HP.

First, I present a few key summary points.

The perception that large NOx co-benefits will result from the addition of

NSCR on 4SRB engines is flawed based on the following:

· NOx performance is very sensitive to the air to fuel ratio

(AFR) and needs to be “more fuel rich” or “air deficient” to achieve NOx

reductions. This is documented in the graph questioned by Miratech and in the

Johnson Matthey information. In addition, the Miratech brochure (page 8/pdf

page 12 of 65) also shows a VERY NARROW operating band for system performance

(i.e., from about 0.986 to 0.996). At leaner operation up to the rich burn

definition of a stoichiometry of 1.1 (which is ~2% oxygen), NOx reductions in

the Miratech “cartoon” are diminished (note that the Miratech picture does not

show actual data, but presents common trends and generally agrees with the

other two graphs). Similarly, the MECA brochure supports that conclusion that

NSCR performance for NOx is very susceptible to the AFR and that CO and

hydrocarbon performance are better under leaner operation (see page 5, of page

6 of 17);

· An AFR set point for engine efficiency (e.g., about 1.05 to

higher) is in contrast with the richer set point requirements for NOx

emissions reduction (i.e. higher fuel use). (For example, Waukesha brochures

indicate an excess air ratio of 1.06 for ”best economy” on rich burn engines

and 0.99 for “Catalytic Converter Input (3-way)”.
Claim of NOx co-benefits at the leaner AFR set points (still within the common

operating range for RB engines) is not accurate or supported by the “cartoon

graphs” of two catalyst vendors (Miratech and Johnson

Matthey) or MECA;

· Richer AFR set points results in higher operating

temperatures and increased maintenance. Emissions of CO, hydrocarbon, and

greenhouse gases (CO2 and methane), as well as ammonia (a particulate

precursor) are also higher at richer set points).

Formaldehyde compliance (if a catalyst is required) is also assured at the AFR

of 1.05 and higher. Thus, there are multiple reasons for an operator to run

leaner – and multiple benefits (for energy efficiency, engine operability, and

emissions).

Claims contrary to these points should be supported with data rather than

“statements” (without supporting data and emissions warranties) from a vendor

with obvious financial stakes in the outcome of the regulation. In addition,

the vendor discusses damage from “over-oxygenation” in its email response to

EPA. However, the vendor brochure indicates that this is only in regard to

NOx reduction (i.e., not formaldehyde performance) per page 11, and occur at

higher than 2%

O2 (i.e., higher than a stoichiometry of 1.1). So, that discussion appears to

be over-emphasized in the vendor email communication, but does indicate

another mechanism for NOx performance to fail (while formaldehyde emissions

would apparently not be compromised per the vendor brochure).

http://ect.jmcatalysts.com/emission-control-technologies-three-way-catalysts

We gave EPA two sources. The EPA note describes only one source. The second

one from Johnson Matthey Catalysts is above. I assume that Matthey is showing

the latest technology on its website. It also shows that the NOx reductions

drop sharply for leaner AFR's above 99.8% AFR.

The source below shows that NOx reductions drops above 99% AFR. The text

below says that "This chart should be zoomed into a realistic area somewhere

between 0.96 lambda (1.040 phi) and 0.99 lambda (1.010 phi).

This is an area where the AFR will be operating." So there is absolute

agreement between those two sources and the Miratech source that to achieve

the significant NOx reductions, you need to have the engine operate between

0.96 and 0.99. This apparently was true of all the old and new catalysts.

That is NOT the issue. We agree you can achieve NOX reductions IF you set in

this region, and we said so. However, it should also be acknowledged that the

AFR “operating window” is very narrow, which speaks to our point in the

difficulty in retaining this performance IF you are targeting NOx reductions.

However, EPA provided us with a key diagram we didn’t have before showing

graphically what we had said already – that the HCHO emissions reductions

increase as you go leaner – and to maximize HCHO emissions you will go beyond

the 0.96-0.99 area. This graph (page 8 of the Miratch manual), shows that the

best removals occur for AFR above .99 thru above 1.10. Miratech also points

out that you shouldn’t go above 2% oxygen (1.1 AFR) in order to avoid hurting

the NOx reductions, but that note doesn't say that it hurts the HCHO

reductions (the EPA note incorrectly says it hurts the ability to reduce “any

pollutants” while the manual at page 11 references ONLY NOx). And the graph

shows that HC reductions continue to grow as the engine leans out. It is also

noteworthy that this is yet another mechanism that can result in performance

failures for NOx.

The EPA response appears to focus solely on the ability to meet the NOx

standard and not the ability to meet the HCHO standard. The issue is

where will the engines be set IF in practice to meet an HCHO standard and will

NOx reductions occur? The Miratech and EPA notes do not say where the desired

AFR window for HCHO is. We believe that HCHO reductions will occur for AFRs

that are greater than 100%, where NOx reductions do not occur, which is

confirmed in the Miratch manual (which is CURRENT TECHNOLOGY). What stops

facilities from doing so in order to

reduce CO, ammonia, fuel efficiency, GHGs, and maintenance costs? This

is the question posed by our earlier comments. EPA didn’t really get a

response on the key issue.

Looking at curve in Figure 2 of the MECA 1997 Report, it appears that the

NMHC control improves as you move from 99% to above 100%. To the extent that

EPA sets an aggressive HCHO standard, the engine is even less likely to

achieve NOx reductions, because it will stay off the rich side of the rich

burn engines. This is consistent with the Miratech graph.

However, EPA does point out this part: “ shows in Figure 2 that the NMHC

reductions will decrease as you lean out the engine.” This implies that you

can’t go too lean, or you would lose the HCHO emissions also – so is this true

of other current NSCRs? And how wide is the lean window where NOX reductions

won’t occur? The reduction in HC emission reductions, however, is not shown

in the Miratech manual. Since the MECA cartoon has little detail, appears to

present both rich burn and lean burn operating ranges, and is not consistent

with others, we expect that cartoon is not representing a negative impact on

HC performance within the “leaner” range for rich burn engines.

Judging from the graph on page 8 of the Miratech manual, in the desired AFRC

window for control, which is narrowly centered around 99%, the NOx reductions

appears around 90%, not 97%, which is only a small reduction from 97%. But I

would say the concern is that to get additional HC reductions, you actually go

past 1.0. But the mfger says that you can damage the ability to reduce NOx
permanently if you go beyond 2% oxygen for extended periods of time (A/F ratio

of 1.1 at 2% oxygen) But that wouldn’t stop a facility from doing so, because

he’s setting for HCHO reductions, not NOx. And if EPA sets an aggressive HCHO

standard, more facilities will need to go leaner than 99% to get to

compliance, and will forego some or most of the NOx reductions. In the

Miratech graph, the NOx reductions do not go to zero, unlike the Colorado

State University results.

In sum, the NOx reductions may not go to zero, but the Actual Data, and MECA

and Johnson Matthey cartoon graphs all show a steeper decline in NOx

performance than the Miratech cartoon. In the leaner area more favored by HCHO

compliance, the NOx reductions go from 97% to somewhat under 10% (according to

Miratech’s cartoon graph). So the NOx reductions can easily be cut by half or

more by going into the lean area according to Miratech’s own brochure.

Therefore, the EPA response did not rebut our concern - and now we have

quantified the effect as somewhere between a 95% reduction under optimal NOx

reductions conditions and maintaining a narrow AFR set point and a no NOx

reduction for individual engines when operating lean.

----- Original Message -----

From: King.Melanie@epamail.epa.gov <King.Melanie@epamail.epa.gov>

To: Higgins, Cortney

Cc: Talcott.Fred@epamail.epa.gov <Talcott.Fred@epamail.epa.gov>;

Wayland.Robertj@epamail.epa.gov <Wayland.Robertj@epamail.epa.gov>;

horowitz.michael@epamail.epa.gov <horowitz.michael@epamail.epa.gov>

Sent: Fri Aug 06 22:59:07 2010

Subject: Fw: Catalyst windows

Hi Cortney,

I am forwarding the email below in response to SBA's claim that NOx reductions

would not be achieved through the use of NSCR on 4SRB engines. This is

information from Miratech who is a large supplier of catalyst technology.

See also their catalyst manual which is attached, which discusses the

potential to over-oxygenate the catalyst if you run it at too high of an

O2. See at the top of p. 11. According to Miratech, saturating it with

too much O2 would result in the catalyst losing the ability to reduce any

pollutants.

I would also reference the information on p. 5-6 in the attached report from

MECA. It says "NOx conversion efficiency drops dramatically when the engine

is run in the lean regime, while NMHC and CO conversion efficiency also

declines somewhat." and shows in Figure 2 that the NMHC reductions will

decrease as you lean out the engine.

(See attached file: icengine.pdf)(See attached file: Catalyst Operating Manual

- 012909B.PDF)

Melanie King

Energy Strategies Group

Sector Policies and Programs Division

Office of Air Quality Planning and Standards U.S. Environmental Protection

Agency

Mail Code D243-01

RTP, NC 27711

Phone: (919) 541-2469

Fax: (919) 541-5450

king.melanie@epa.gov

----- Forwarded by Melanie King/RTP/USEPA/US on 08/06/2010 10:38 PM

-----

|------------>

| From: |

|------------>

>-----------------------------------------------------------------------------

---------------------------------------------------------------|

|"Kevin O'Sullivan (MIRATECH)" <kosullivan@miratechcorp.com>

|
>-----------------------------------------------------------------------------

---------------------------------------------------------------|

|------------>

| To: |

|------------>

>-----------------------------------------------------------------------------

---------------------------------------------------------------|

|Melanie King/RTP/USEPA/US@EPA

|

>-----------------------------------------------------------------------------

---------------------------------------------------------------|

|------------>

| Cc: |

|------------>

>-----------------------------------------------------------------------------

---------------------------------------------------------------|

|"David Zenthoefer" <dzenthoefer@miratechcorp.com>

|

>-----------------------------------------------------------------------------

---------------------------------------------------------------|

|------------>

| Date: |

|------------>

>-----------------------------------------------------------------------------

---------------------------------------------------------------|

|08/06/2010 06:04 PM

|

>-----------------------------------------------------------------------------

---------------------------------------------------------------|

|------------>

| Subject: |

|------------>

>-----------------------------------------------------------------------------

---------------------------------------------------------------|

|FW: Catalyst windows

|

>-----------------------------------------------------------------------------

---------------------------------------------------------------|

Melanie –

We haven’t met – and David was tied up so I reached out to one of our experts

and his abridged response is below. As you can see, we believe the original

investigator is dealing with dated and limited material.

I’m not much on sugar coating – so my simple synopsis is if you’re designing

rules on the information provided us to respond to, there is a
lot more work to be done and more technology to understand than what we were

presented.

I’d be pleased to discuss this in more detail with you or the investigator.

My best -

Kevin

Kevin R. O'Sullivan, President and Chief Operating Officer, MIRATECH

Corporation

Primary: 918.628.6110 (Office Direct), Alternate: 918.630.1658 (Cell)

Emission Solutions for Industrial Engines: kosullivan@miratechcorp.com or

www.miratechcorp.com

Fax: 918.933.6220, 420 South 145th East Avenue, Mail Drop A Tulsa, OK

74108 - 1305

From our consultant:

I've looked over this BS and it looks to me like whoever submitted this to the

EPA is banking everything off of data that they have collected years back or

with catalyst that were manufactured years ago. Looking at

what he is saying, he has a catalyst that is using the older loadings and

designs that only give 90% reduction. The current 0.5 gram catalyst is

achieving 96 to 97% reduction.

The next thing that he is basing his information on is a very narrow operating

window (lambda window). Most catalyst manufactures today have opened the size

of the operating window allowing a greater deviation in the AFR control and

still be within the desired emissions levels.

He is defining a Rich Burn engine as an engine with a Lambda setting of 1.10.

I believe the EPA defines any engine running with 2 percent of oxygen or less

to be a rich burn. A few years back they defined it as 4%

or less. Everyone in the free world that has ever seen a catalytic converter

knows that it must operate at 0.5% or less.

The chart that the guy provided, in my opinion, is not accurate. Of course you

can get these readings with as large of a swing that they are

inducing on the AFR and catalyst. This chart should be zoomed into a realistic

area somewhere between 0.96 lambda (1.040 phi) and 0.99 lambda

(1.010 phi). This is an area where the AFR will be operating. The ammonia

levels that he is showing is higher than anyone would expect.

Typically you start smelling ammonia at about 30 ppm. They are saying that

this level is showing up at about 0.985 lambda.

Lastly, the AFR issue. If they are testing with a low end system, yes they

will have problems maintaining the operational window. The better the

controller, the tighter the hold on the operational window.

The bottom line is, these guys are throwing both the AFR and catalyst under

the bus with data from only one source. Modern AFR technology and modern

catalyst technologies are far more superior that the older stuff.

-----Original Message-----

From: David Zenthoefer

Sent: Friday, August 06, 2010 9:19 AM

To: John Sartain; Kevin O'Sullivan (MIRATECH)

Subject: FW: Catalyst windows

Kevin,
Can you take a pass at this for the EPA, this is helping to finalize the

NESHAP rule due out next Tuesday.

David

David Zenthoefer, Vice President - Sales and Service MIRATECH Corporation

Primary: 918.640.1140 (Cell)

Emissions Solutions for industrial engines: dzenthoefer@miratechcorp.com

or www.miratechcorp.com

Fax: 918.933.6236, 420 South 145th East Ave, Tulsa, OK 74145-4712

-----Original Message-----

From: King.Melanie@epamail.epa.gov [mailto:King.Melanie@epamail.epa.gov]

Sent: Friday, August 06, 2010 9:01 AM

To: David Zenthoefer

Subject: Re: Catalyst windows

Hi David,

Thanks so much to you and John for speaking with me this morning. The issue I

am trying to resolve is whether you will get NOx reductions from

a 3-way catalyst that is installed on a rich burn engine to meet CO or VOC

emission standards. The argument that is being made is that they will set the

engine up specifically to get the CO/VOC reductions and not

achieve any NOx reductions since they aren't trying to meet a NO limit as

well. Below I have copied the information that was sent to us by one

of the interagency stakeholders who is suggesting that little to no NOx

reductions will be achieved. From speaking with you this morning, my

understanding is that running the engine too lean will saturate/poison the

catalyst and the reductions of all 3 pollutants will be decreased.

Below is the information that was sent to me by the interagency reviewer

to support the claim that little to no NOx reductions will occur:

If you get NOx reduction with NSCR it is usually relatively high – e.g.,

90% or more. The problem is that the NOx performance is very sensitive to the

air to fuel ratio (AFR) and the stream needs to be “more rich” (i.e., more

fuel rich or air deficient). A lesser NOx reduction (e.g., 20 – 60% NOx

reduction) with NSCR is typically not seen, because the performance curve

(versus AFR) is very steep – meaning that you go from no NOx reduction to

relatively high NOx reduction (e.g., 80% or

more) with very small changes to AFR. Similarly, if set for “richer”

operation with NOx reduction, relatively small changes in AFR can move the AFR

more lean and significantly impact NOx performance. Thus, if an

operator installs NSCR to meet a NOx limit, the set to provide a better

assurance of emission performance is often accomplished by establishing a

“richer” set point (which can result in significant ammonia emissions). In

this scenario, there is more of an operating window before minor AFR changes

can move “too lean” and significantly compromise NOx performance. Those

richer set point also result in lower

efficiency / higher fuel use, more hydrocarbon (HC) emissions, and hotter

operation – and these conditions affect maintenance requirements because the

HC and higher temps impact performance and increase maintenance frequency (and

related costs).

An example of NOx (post NSCR catalyst) versus AFR for a RB with NSCR is

provided here. Note the “stoichiometric ratio” (SR) is the theoretical amount

of air relative to the amount required to burn all of the fuel – i.e., at 1.00

there is just enough air to burn all the fuel. From the scale on the x-axis,

a change in the amount of air by 1 or 2% dramatically changes the NOx

emissions (and ammonia and CO emissions).
This level of AFR control is difficult to maintain on a continuous basis. It’s

also not reasonable to operate in a region of the “NOx curve” that provides

intermediate levels of NOx reduction so in general NOx reduction with NSCR

close to an all or nothing proposition. Also – as a reminder, the definition

of “rich burn” is an engine with a stoichiometric ratio up to 1.10 (beyond the

scale of this graph). As you can see from the graph, the NOx emissions on the

right side of the graph (from SR of about 0.99 or higher) have high NOx

indicative of very

little or no NOx reduction. This relates to our discussion that NOx

reductions cannot be presumed with NSCR – and operators can achieve better

efficiency, lower fuel use, and lower greenhouse gas emissions by

running leaner where NSCR will not reduce NOx.

Also for the NOx data – the marginal relative change in the 3 data points to

the right (from about 2100 to about 2650 ppmv) is due to changes in the inlet

NOx and not from NSCR reduction – i.e., the inlet NOx versus AFR is also

dependent on AFR at this operating threshold where you cross from “rich” to

“lean”, and the NOx reduction across the catalyst is insignificant. Note that

the one NOx point at about 850 ppmv is 58% reduction and the three low NOx

points on the left are about

98% reduction for these tests.

(Embedded image moved to file: pic10264.gif) Since facilities will be

attempting to meet an air toxics standard, the preferred operation will use a

stoichiometric ratio of 0.99 or more, which would be on the “fuel lean” side

(right hand side) of the graph.

However, the NOx reductions will only occur on the rich side (left hand

side) of the graph – in this case approximately 0.98 or less. In addition to

good HCHO emissions performance, there are additional reasons for being on the

lean side of the curve – reduced fuel consumption, associated reductions in

greenhouse gas emissions (i.e., lower CO2 and methane), reduced maintenance,

and avoidance of ammonia and CO emissions. The NOx reductions go very quickly

from roughly 98% to 0% once you move from richer settings to leaner operation

above about

0.98. Also, the air to fuel ratio differences are very small and given

some instability of the settings of these engines, maintaining a precise

setpoint is difficult and you will need to set an even leaner setting optimize

engine operability and effieciency – or, conversely, set a

richer setting to ensure NOx reductions. The above graph is from a

rich burn engine tested by Colorado State University. Unless EPA is also

setting a NOx limit with the HCHO limit, these desired NOx reductions are

unlikely to occur.

EPA may wish to review additional data to see how under what AFR ratios,

both the HCHO number and the desired NOx reductions can occur (by how much and

whether these overlap), although I don’t know how this result can be achieved

under the current standard.

Melanie King

Energy Strategies Group

Sector Policies and Programs Division

Office of Air Quality Planning and Standards U.S. Environmental Protection

Agency

Mail Code D243-01

RTP, NC 27711

Phone: (919) 541-2469

Fax: (919) 541-5450

king.melanie@epa.gov

|------------>

| From: |

|------------>
>-----------------------------------------------------------------------------

-------------------------------------------------------------|

|"David Zenthoefer"

<dzenthoefer@miratechcorp.com>

|

>-----------------------------------------------------------------------------

-------------------------------------------------------------|

|------------>

| To: |

|------------>

>-----------------------------------------------------------------------------

-------------------------------------------------------------|

|Melanie

King/RTP/USEPA/US@EPA

|

>-----------------------------------------------------------------------------

-------------------------------------------------------------|

|------------>

| Date: |

|------------>

>-----------------------------------------------------------------------------

-------------------------------------------------------------|

|08/06/2010 09:39

AM

|

>-----------------------------------------------------------------------------

-------------------------------------------------------------|

|------------>

| Subject: |

|------------>

>-----------------------------------------------------------------------------

-------------------------------------------------------------|

|Catalyst

windows

|

>-----------------------------------------------------------------------------

-------------------------------------------------------------|

David

David Zenthoefer, Vice President - Sales and Service MIRATECH Corporation

Primary: 918.640.1140 (Cell)

Emissions Solutions for industrial engines: dzenthoefer@miratechcorp.com

or www.miratechcorp.com

Fax: 918.933.6236, 420 South 145th East Ave, Tulsa, OK 74145-4712 [attachment

"Catalyst Operating Manual - 012909B.PDF" deleted by Melanie
King/RTP/USEPA/US]

“This message and any attachments may contain FW Murphy information that is

highly confidential, privileged, and exempt from disclosure. Any recipient

other than the intended recipient is advised that dissemination, distribution,

copying, or other use of this message is strictly prohibited. If you have

received this message in error, please notify the sender immediately, plus

delete the message and any backups.”