----- Forwarded by Melanie King/RTP/USEPA/US on 08/09/2010 11:58 AM

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>--------------------------------------------------------------------------- ---------------------------------------------------------------| |Melanie King/RTP/USEPA/US |

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |------------> | To: | |------------>

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |Cortney_Higgins@omb.eop.gov |

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |------------> | Cc: | |------------>

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |Fred Talcott/DC/USEPA/US@EPA, RobertJ Wayland/RTP/USEPA/US@EPA, Michael Horowitz/DC/USEPA/US@EPA |

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |------------> | Date: | |------------>

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |08/06/2010 10:59 PM |

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |------------> | Subject: | |------------>

>--------------------------------------------------------------------------- ---------------------------------------------------------------| |Fw: Catalyst windows |

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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 AFRmore 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]

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