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AF&PA-AWC Responses to EPA’s questions on PRR and Railroad ties

(May 2013)

In response to questions asked by EPA in early May, AF&PA and AWC are 

providing the responses below. We are deferring to the CMRA and BPA to respond to 

the questions on processed C&D. 

Before we respond to these narrow questions, it is important to remind the Agency 

we have provided extensive information to EPA over the last three years on these two 

materials from the ANPRM, through the June 2010 proposal and on to the December 

2011 Reconsideration rulemaking. In addition, we have provided various “white papers” 

and NCASI technical bulletins which are in the rulemaking record. These materials 

clearly show that these materials are highly valued fuels and are managed like other 

traditional biomass fuels and burned in boilers that can accommodate a wide variety of 

moister biomass materials. We remain opposed to the application of a “designed to 

burn” test as part of the legitimacy criteria when EPA has the discretion to consider 

other factors in making a determination under 241.4. 

EPA Question: “Paper Recycling Residuals (PRRs) average Btu value is 3,700 Btu/lb as 

fired. You previously indicated that some PRRs are over 5,000 Btu/lb; however, can 

you explain why there are much lower values? For example, do the low values come 

from samples of PRRs burned in units that can handle high moisture content and thus, 

there has been very little processing, if any, to remove moisture? 

Answer: 

Yes, the PRRs with lower Btu values are combusted in units that can derive fuel value 

from materials with high moisture content without processing those materials. 

The 3,700 Btu/lb value was derived from NCASI Technical Bulletin 806 with an average 

dry value of 9100 BTU/lb with solids around 40%; the range of dry BTU is 8K to 12K 

and solids vary from 40-60% with an average of 50%. A survey of about 10 companies 

finds some reporting higher BTU values than the older 3700 BTU/lb value and other 

companies reporting lower BTU values. Lower BTU values are due to higher moisture, 

less solids, types of fibers being processed (such as, saturated), and/or fewer non-fiber 

packaging materials. Mills manage the moisture content of all fuels including PRRs 

based on combustion efficiency of the boilers which function exceedingly well with high 

moisture fuels. 

EPA Question: What is the split between PRRs with BTU/lb as fired under 5000 and 

over 5000?” 

Answer: 

The BTU value of PRR is a continuum that is influenced by amount of solids, fiber 

content, moisture, presence of non-fiber packaging materials, and combustion 

conditions necessary for the effective operation of the boiler, but most of the PRRs are 
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below 5000 on a wet basis since the average is less than 5000 BTU/lb. However, wetter 

biomass fuels are also in that same range and can have a lower Btu value than PRR at 

times. From the boiler’s vantage point, burning wet biomass or PRRs is essentially the 

same and the two materials are managed similarly as well. The boilers used, like 

stokers and FBC, often have over-fire and/or under-grate air that assists the efficient 

burning of wetter fuels. Consistently wet materials are handled well in the boiler leading 

to fewer temperature swings and minimized boiler tuning adjustments. For PRR it would 

be inappropriate to consider a moisture level benchmark when determining if a material 

is a non-waste fuel because the boilers at pulp and paper mills can cost-effectively 

recover energy from PRRs. 1

EPA Questions on Railroad ties or Rail Derived Fuel (RDF):

EPA Question: Of the AF&PA member boilers burning creosote-treated railroad ties, 

how many (or what percentage) burn or can burn fuel oil during normal operations? 

Answer: The overwhelming majority of RDF burned at paper mills are burned in boilers 

that are fully capable and permitted to burn oil at maximum capacity rating. Most of 

these boilers (80 percent) can or do burn oil during operating conditionsoutside of 

startup and shutdown periods. However, we believe start-up and shutdown are part of 

normal operations since they cannot be eliminated and common to all boiler systems. 

Therefore, if EPA considers defining “designed to burn” further or “normal operation” it 

should include start-up and shutdown periods. 

The percentage of oil the boiler is capable of burning varies but can be up to 100 

percent of the energy load. The largest consumer of RDF uses boilers that are fully 

capable of, permitted to, and do burn fuel oil at maximum capacity rating. However, at 

the 20 percent of boilers that do not burn oil during normal operations, the use of RDF is 

no less legitimate. It is used as a fuel. Thus, EPA should not put any restrictions on 

“normal operations” 

EPA Question: Are there differences among boiler types (stoker boiler, traveling grate, 

circulating fluidized bed etc.) with regard to what it takes to modify the unit so it could 

burn fuel oil? 

Answer: No, these boiler types have relatively tall combustion chambers that make 

them ideal for burning multiple fuels from solids to liquids to gas. An oil burner system 

would be added that would require several ports to deliver the fuel. 

                                                           

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 See 76 FR 15487: “While the meaningful heating value of the OCC rejects is lower than 5,000 Btu/lb, as 

fired, it can still meet this criterion if it can be demonstrated that the unit can cost-effectively recover 

energy from a non-hazardous secondary material.” 
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EPA Question: Is it always as simple as installing a delivery system and a nozzle? 

Answer: Burner systems can be installed because there is room in these tall boilers 

and the systems. However, engineering the system can be complicated and the cost of 

the delivery system can be significant ($100Ks) depending on the amount of fuel oil to 

be burned in the boiler. 

EPA Question: Do states typically require different air pollution control devices for units 

burning fuel oil (as hinted at by the reference to SO2 emissions in the AF&PA 

response)? 

Answer: No, controls for solid fuels like ESPs are sufficient; oil is generally easier to 

burn than solid fuels. There are frequently sulfur content limits for the oil burned that 

varies by state and sometimes a lower NOx limit when burning multiple fuels.