combustionsurvey - ON RECONSIDERATION: ABMA COMMENTS ON THE FEBRUARY 

2011 RULES FOR INDUSTRIAL, COMMERCIAL, AND INSTITUTIONAL BOILERS AT 

MAJOR SOURCE FACILITIES 

 

Who Are We? 

I speak on behalf of the membership of the American Boiler Manufacturers Association (ABMA), which is 

composed of corporations and individuals having experience and technical expertise in the design, technical 

application, fabrication, installation, operation, maintenance and repair of >400,000 Btuh (heat input) 

commercial, institutional, industrial and power-generating boiler, combustion, heat recovery, emissions 

controls, instrumentation and related equipment and systems – the products and services required for 

compliance with final Major Source NESHAP requirements. Members of the ABMA account for well over 60% of 

all commercial, institutional, and industrial conventional boiler system sales in the United States, representing 

approximate annual gross sales of between $4 and $5 billion. In addition to new sales, these manufacturers are 

responsible, at least in part, for the design and manufacture of most of the existing boiler stock to which these 

rules will apply. 

 

ABMA manufacturers conduct business in the “real world” of boiler technology, and manufacture “real-world” 

boilers. If a mandate or numeric emissions limit is technically unobtainable, historically it has been this 

industry’s mission – and success -- to undertake the research and new product development necessary to 

constructively respond to exigent technical requirements; it will be no less the case in this stance and with 

regard to any enforceable Major or Area Source Industrial Boiler MACT rules. 

 

As to the cost-effectiveness of these rules, whether boiler-owner compliance with these rules can be termed 

cost-effective or not depends entirely on the state of the boiler system in question, the extent to which 

upgrades, and modernizations and/or add-ons are really necessary to achieve full compliance -- after careful 

analysis through a baseline testing and optimization programs -- and frankly, how constructively the owner 

wishes to work with the technical experts in the boiler and emissions-controls industry in devising cost-effective 

ways to reach compliance. The good news for boiler owners is that by starting with an analysis of what they 

have and how it operates, they may very well find – as a result of the new, final rules -- that little or no 

investment is required on the back end as far as new equipment is concerned. In general, compliance will in 

some extreme cases require a “system solution” that includes the fuel, boiler, burner, and a range of readily 

available, proven air quality compliance solution (AQCS) equipment. There are no universal solutions; all plants 

are unique – varying widely from boiler room to boiler room -- as to their existing AQCS configuration, available 

space, age of equipment and other state and local regulations with which the plants must comply. There is no 

one-size-fits-all applicability of the exigent rules; likewise, the rules do not affect every boiler room or every 

facility in the same way or at the same cost. 

 

Additional Comments

ABMA commends the Environmental Protection Agency (EPA) for its reassessment of past data, fuel/technology 

From: Randy Rawson <Randy@abma.com>

To: "combustionsurvey@erg.com" <combustionsurvey@erg.com>

Date: 7/18/2011 7:41 AM

Subject:

 

ON RECONSIDERATION: ABMA COMMENTS ON THE FEBRUARY 2011 

RULES FOR INDUSTRIAL, COMMERCIAL, AND INSTITUTIONAL BOILERS AT 

MAJOR SOURCE FACILITIES

Attachments: appendixf_co_span_adj_guid.pdf

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categories and corresponding numeric emissions limits leading to the final air toxics standards as promulgated 

on February 21, 2011, and we are happy to provide this additional perspective during this period of 

Reconsideration. 

 

There are areas of the final rules that require attention and reconsideration, however, and we appreciate this 

opportunity to address those. 

 

Existing coal-fired stokers – The February 2011 published CO values are much more realistic and obtainable 

when considering the wide range of users, equipment types and fuel ranges involved. The fact is that under 

most existing grate-firing applications, the 270 ppm value is obtainable with cost effective solutions like tuneups, secondary air, and distribution improvements. All these are actions that account for improved combustion 

and enhanced efficiencies. This value will also be helpful in obtaining current or future reductions in NOx 

emissions, inasmuch as most, if not all, NOx reduction strategies increase CO. However, the Mercury (Hg) and 

Dixon/Furan (D/F) continue to be very low and problematic values that, when combined with the Particulate 

Matter (PM) requirements, will necessitate more extensive spending for flue gas scrubbers and bag house 

collection systems. We are not saying that the Hg and D/F numeric limits, although very low, are unachievable

only that, when combined with the PM limits, they are unachievable through combustion only. The basic 

reduction technologies exist, but we are simply not sure if, despite having the technology, the limits are yet 

obtainable in all instances for the combined limits required. The D/F, Hg relationships have not been well 

studied in industrial units due to the variety of combustion technologies and fuels. Alternatives to flue gas 

scrubbers and bag house collection systems include fuel switching or curtailing facility activity. 

 

New coal -fired Stokers – Simply put, the February 2011 numeric emissions limits proposed for this category are, 

in our considered judgment, still unachievable for every pollutant. The proposed CO value of 6 ppm @3% O2

is 

barely obtainable for a natural-gas fired boiler, where the fuel is homogenous and can be decisively mixed and 

reacted with the combustion air. Enforcement of the presently enumerated emissions limits and as required for 

every pollutant will effectively prohibit new coal-firing in the United States. Despite the ICR boiler data, the 

agency has actually truncated all the real data that's below what Method 10 – the known and widely-used 

method for CO measurement -- says the accuracy should be; therefore destroying the variability. Emission 

limits for CO is one of the cases where MACT is based on math and has nothing to do with technology or 

achievability. [See attached 01/20/2011 Memo, “Measurement Imprecision for Carbon Monoxide,” by Peter 

Westlin (EPA/OAQPS/SPPD)] What is seemingly being said in the attached memorandum is that there is agency 

recognition that instrument span and calibration do have an effect on the data obtained; but, rather than 

actually testing for the real emission, the agency has introduced a method of mathematically calculating what 

the floor data should be, resulting in the proposed CO values. In order to restore confidence in not only the 

efficacy of the established numeric limits set but in the methodologies on which the limits are crafted, as well, 

this needs to be reconsidered and changed to be better geared to reality and more in line with technicallyaccepted values. 

 

More on CO: Boiler industry/stoker data and experience indicate that the 270 ppm of CO is possible for a high 

number of existing facilities. Without conventional NOx control, a new unit has potential of 50-100 ppm based 

on a 24-hour average at MCR load. Factor in load changes, fuel variability, future NOx reduction...then 150-300 

ppm is more realistic. If you are assuming that CO on a new coal-fired stoker can be controlled by an SCR, just 

understand that we have no knowledge of any existing application of an SCR (to address either CO or NOx) for a 

coal-fired stoker. SCR providers warn that the high carbon fly ash would destroy the catalyst very quickly, let 

alone what temperature profile is needed to activate the media. The only SCR for coal firing that we know of 

has been done on PC units, and these are extremely different combustion technologies. In the opinion of those 

who should know through experience and technical expertise – and have to commercially guarantee results: a 6 

ppm limit on a new coal-fired stoker is simply not obtainable on a continuous basis for industrial boilers. This is 

a value associated with natural-gas fired package boilers and not even Low NOx units. The ABMA-preferred CO 

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range – again representing the technology base in this country -- for new coal-fired units should be in the 50-150 

ppm @ 7% O2.

 

Existing Hybrid Biomass Suspension/Grate – this is a new category from previously proposed rules. EPA 

indicates that the addition of this category was due to prior comments from facilities combusting bagasse or 

refuse biomass left over from cane sugar processing. EPA observes that the technology or combustion process 

associated with this category is a system allowing for biomass fuels to be distributed into a boiler to allow all 

particles additional time to first drive moisture from the fuel particle(s) and then volatize the fuel when in flight. 

Smaller particles would be expected to never reach the grate surface as these particles would be burned in 

suspension. Larger particles would land on the grate where the process of drying, volatizing and combustion of 

the fixed carbon would be accomplished. The EPA observation/description goes on to indicate that those 

particles actually landing on the grate would be subjected to higher excess air values to better combust the fuel 

particles. In addition the description indicates that steam load response rates and thermal input rates are 

higher. 

 

The foregoing comments and description by EPA of the new hybrid biomass suspension /grate category is also a 

near-perfect description of a traditional spreader-type stoker using higher moisture fuels and fuels having a 

wide variety of particle sizing. 

 

ABMA and the Detroit Stoker Company, a long-time member of the ABMA and the largest provider of spreaderstoker systems in the world -- as well as a number of systems for bagasse-fired facilities -- acknowledge that 

there are specific challenges for bagasse as a fuel. However, we also believe that nearly all the biomass boilers in 

the industrial sector have specific challenges. The description for this sub-category specifically mentions a fuel 

type (bagasse) with a moisture range of 48-50%. This departs from EPA’s past practices and policies of decidedly 

not categorizing fuel types to this extent. The proposed CO limit for this category is 3,500 ppm @ 3% O2

– a 

tremendously high value based on data taken mostly from antiquated units. Regardless of fuel, the new 

Existing Hybrid Biomass Suspension/Grate, as defined, is nothing more or less than a “spreader stoker,” as 

typically defined by current boiler-stoker industry terminology. If EPA is serious about its intent to stay away 

from fuel classifications, then it ought not to be crafting categories to accommodate specialized fuels like 

bagasse. Regardless of what you might name it, the equipment in question is, again, a “spreader stoker.” 

 

In addition, the 3500 ppm (existing) and the 1500 ppm (new) limits are, in our opinion, a bit excessive for the 

Hybrid classification. For existing facilities, something in the range of 1000-12000 ppm would be more 

reasonable. 

 

Clarity would be served by changing the Hybrid sub-category to “Spreader” and by then adding a Mass fed 

stoker category. But more importantly, ABMA strongly believes that the government/EPA should not take on 

the role of choosing – through regulatory mandates -- one heat-transfer or combustion technology over any 

other to meet exigent needs. Those decisions must be left to an informed market place. With respect to new 

units, it is vital that all competing technologies – whether they be spreader/hybrid, mass fed or fluidized bed 

combustion – have and be expected to comply with the same emissions limits values. In this way EPA avoids 

“designating a preferred technology,” and leaves that decision to the owner to make, based on need and 

available technology. EPA did this for Hg and PM; it should likewise be done to D/F and CO values. 

 

New Biomass Hybrid Suspension/Grate – Again, this is a new category that, judging by the Agency’s 

commentary, describes a spreader stoker. The proposed CO limit is half as much as an existing unit (1,500 ppm 

@ 3%O2). Yet it is still is much higher, regardless of equipment and technology utilized today by today’s 

standards. This simply does not make sense, particularly since the values for the remaining pollutants, with the 

exception of D/F, are very limited and also equivalent limits to all other new biomass categories, regardless of 

technology. If in fact, it is the contention of the Agency’s research that values of PM, HCl and Hg should be 

Page 3 of 4
equivalent; then ABMA believes that values of CO and D/F would also be equivalent. Without equivalency, there 

would be a clear advantage to technologies that are not necessarily as environmentally conscientious or as 

reliable and cost effective. 

 

Existing Biomass Stoker/other – Until the addition of the Biomass Hybrid Suspension/Grate Category, all grate or 

stoker combustion systems would have fallen in this category. The new CO limit for this Category is 490 ppm @ 

3% O2

. As a general rule, this proposed value would accommodate a wide variety of existing biomass-fired grate 

systems, utilizing a wide range of fuel moistures. Certainly some facilities would have to add to or refurbish their 

combustion system(s) and evaluate operating procedures and fuel management practices. We would also note 

that other values for PM and Hydrochloric acid (HCl) are more in line with what existing facilities could 

potentially achieve. Yet values of D/F are still extremely low and likely incapable of being achieved without flue 

gas cleaning equipment. 

 

EPA has avoided fuel classifications, particularly for biomass/renewable fuels. This is unfortunate; fuel moisture 

does have a big effect on CO values. However, and in the spirit of showing the willingness to consider arguments 

regarding technology differences. EPA should understand that there is a big difference between a mass fed 

stoker grate and a spreader fired stoker grate. This is true of coal and biomass/renewable fuels. We believe that 

when looking at the CO top performers, EPA will see a difference between mass and spreader units. In fact, we 

think we have already identified a couple of Mass fed units that are top CO performers used as biomass stoker 

floor data and potentially one that is actually a suspension fired unit, yet placed in the Stoker/other category. 

We would promote the concept of the biomass Hybrid units being classified as Spreader stoker and a new subcategory for mass fed stoker. Certainly this would accommodate both new and existing biomass combustion 

owners and developers. 

 

In conclusion... 

 

The ABMA strongly urges EPA to conduct its reconsideration in a technically-defensible manner that also 

minimizes the risk of significant delays that would occur if the rule is overturned for procedural or substantive 

deficiencies. Needless to say, as well, the reconsideration should be conducted in a timely and efficient manner 

to as to preclude further market uncertainty, confusion and fears. It should be remembered that section 112(j) 

of the Clean Air Act specifically provides that where EPA fails to implement a MACT standard in a timely manner, 

state and local permitting authorities must develop and implement equivalent limitations on a case-by-case 

basis. On top of past and more recent court decisions, further delay resulting from the stay issued by EPA or 

from any subsequent adverse ruling by the courts could trigger the necessity for state and local intervention. 

That eventuality does not portend the type of market certainty we need at this point. 

 

The American Boiler Manufacturers Association hopes the foregoing not only contributes to the technical 

debate but raises questions the answers to which may be helpful in understanding complex interrelationships in 

the boiler world as you go about reconsidering the final rules. 

 

W. Randall Rawson

President/Chief Executive Officer

American Boiler Manufacturers Association

... representing the best of the boiler industry ...!

8221 Old Courthouse Road, Suite 202

Vienna, Virginia 22182

Telephone: 703/356-7172

Fax: 703/356-4543

BlackBerry: 703/967-8058

Satellite Office Telephone: 703/729-7510

Email Address: randy@abma.com

Website: http://www.abma.com

 

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