10/31/2016

Review of Fluorotelomer Incineration ECA Final Report

1/3

Report Title: Amended Final Study Report

ECA Incineration Testing Program: Laboratory Scale Incineration Testing 

of Fluorotelomer-Based Polymers

December 22, 2008

Review by: Maj’d El-Zoobi

OPPT/EETD/CEB

Phase I PFOA Transport Testing:

1. Reactor Temperature Profile:

(A. Experimental Apparatus / 2. Reactor Temperature Profile and Related 

Calculations / P.19)

The reactor consisted of a 1.4 cm diameter quartz tube placed in a heater used for 

supplying heat to maintain the reactor at the desired temperature. The reactor outside 

wall temperature was measured during the experimental runs, but the reactor inside 

temperature (temperature of reactor contents) was only measured during the heater 

calibration run. 

The effective reactor length (distance in reactor during the experimental run wherein 

temperature was presumed to be at the set-point of 250 C) was determined during the 

heater calibration run by measuring the inside temperature of the reactor while the 

reactor walls are being heated and N2 is flowing in the reactor at 1,200 sccm (standard 

cubic centimeters per minute). 

In contrast, experimental runs consisted of combined air flow at 1378 sccm and water 

vapor flow at 158.2 sccm. Given the difference between the heat capacities at 

constant pressure (Cp) of nitrogen, oxygen, and especially water vapor (~ 7, 7.25, 8.5 

cal/gmol C at ~ 500 C, respectively), and the different heat transfer effects resulting 

from the two different flow rates and compositions, the actual temperature profile 

may be different from the assumed one resulting in a different residence time at the 

temperature set-point than presumed. Based on this, it is recommended that the 

report authors conduct an analysis of error to determine whether there is any 

significant difference between the temperature profile of the reactor during the 

calibration of the reactor heater, and the actual temperature profile occurring during 

the experimental runs.

Phase II Incineration Testing:

1. Reactor Temperature Profile: 

(F. Combustion Testing / 1. Experimental Apparatus / a. Reactor Temperature 

Profile and Related Calculations / P.31):
10/31/2016

Review of Fluorotelomer Incineration ECA Final Report

2/3

Similarly to phase I testing, the temperature profile of the reactor during the 

experimental runs was presumed to be identical to the temperature profile that was 

measured during the heater calibration run. This method for establishing the 

temperature profile during the experimental runs was specified in the phase II testing 

QAPP (OPPT-2004-001-0116.1) because “it is not practical to directly monitor the 

inside gas temperature at the midpoint of the reactor tube during each experimental 

run.” Also, the effective length of the reactor (distance in reactor during the 

experimental run wherein temperature was presumed to be at 1000 C) was determined 

based on this measured temperature profile. During heater calibration, the inside 

temperature of the reactor was measured along the reactor length while the reactor 

walls were heated using the heater, and synthetic air was flowing in the reactor at 

600 sccm. 

The following questions are related to the heater calibration:

The reactor was held at 1000°C for most of its length, but the heater temperature setpoints were in the range of 979°C to 993°C. However, heat transfer from heater to 

quartz tube requires that the temperature of the earlier be higher than that of the later

which is contrary to what is reported; is this explained by an erroneous heater 

temperature controller, such that the actual heater set-point is actually greater than 

1000°C? Also, why does the reactor’s temperature drop beginning at length 32 in.? 

Is that because the heater ends at this length and does not cover the entire reactor? 

Even if that were the case, it is surprising that temperature would drop 600°C in the 

span of only 4 in. due to ambient cooling only (ie, without the use of a cooling

device.) It is recommended that these questions be addressed by the report authors.

In contrast to the heater calibration run, reactor feed during the experimental run 

consisted of methanol fuel and the vaporized test material in addition to synthetic air. 

Methanol and the test material undergo an exothermic combustion reaction and an 

endothermic thermal degradation reaction respectively whose heat effects, depending 

on their magnitude, may influence the temperature profile in the reactor that is formed 

due to the heating by the heater. Appendix 7 of the report ((OPPT-2004-001-0126.7) 

contains detailed stoichiometric calculations, but does not contain any reference to 

heat effects. It is recommended that the report authors conduct an analysis of error to 

determine whether the reaction heat effects will cause any significant difference 

between the temperature profile of the reactor during the calibration of the reactor 

heater, and the actual temperature profile occurring during the experimental runs to 

ensure that the correct effective length was determined and consequently that the 

desired residence time of 2 sec. was actually established.

2. Consideration of Formation of Other PFC:

A determination of whether other perfluorinated chemicals (PFC) were formed as a 

result of the thermal destruction of the composite test material is of interest. 
10/31/2016

Review of Fluorotelomer Incineration ECA Final Report

3/3

Any residue remaining on the pyroprobe after an experimental run is of interest in this 

regard. According to Table 8, “Pyroprobe Cartridge and Sample Weight 

Measurement for FTBP Composites”, a residue was formed on the pyroprobe in two 

of the nine experimental runs. A 3μg and 4μg residue was formed in runs FTBP1-1 

and FTBP2-3 respectively. Taking into account balance accuracy of ±2.5 μg, the 

amount of residue is 0.5μg and 1.5μg for runs FTBP1-1 and FTBP2-3 respectively. 

However, in the report (F. Combustion Testing / 2. Description of Test Conditions / a. 

Test Substance Weight Measurements / P. 33) it is stated that the residue reported in 

Table 8 for these two runs is within the weighing accuracy of the microbalance. This 

statement should be explained by the report authors and the formation of the 

implications of the formation of the residue should be discussed.

Another consideration in regard to the possibility that other PFC were formed is 

whether a fluorine mass balance closes. This has yet to be determined by the 

reviewer. Note that a carbon mass balance is not of use in this regard because 

methanol is by far the source of carbon in the feed.