AQ_F_0900009_20200512_ST_RvwMemo

Division of Air Quality
May 12, 2020
MEMORANDUM
To: Heather Carter, Fayetteville Regional Supervisor
From: Gary L. Saunders,Stationary Source Compliance Branch Superviso
Subject: The Chemours Company—Fayetteville Works
Fayetteville, Bladen County, North Carolina
Facility ID. No.0900009, Permit No. 03735T47
Performance Testing for Destruction Removal Efficiency of the Thermal Oxidizer on
February 28-29, 2020 by Weston Solutions, Inc.
Tracking No. 2020-105ST
Summary
On February 28 and 29, 2020,the Chemours Fayetteville Works conducted performance testing on the
Thermal Oxidizer(TO) system installed to destroy fluorinated compounds produced and released from
production areas at the site. The purpose of the performance testing was to demonstrate compliance
with the 99.99%control (destruction)of the fluorinated compound emissions required by a Consent
Order signed and filed with the Bladen County Superior Court on February 25,2019. The facility's air
emissions permit also requires 99.99%control through the TO system.
Gases from the monomers and polymers areas of the Chemours Fayetteville Works are conveyed
through separate vent systems to the TO for thermal destruction and control. After introduction into
the thermal oxidizer through the separate systems,the fluorinated organic compounds are thermally
decomposed in the high temperature zone of the TO and converted to inorganic hydrogen fluoride (HF).
The gases from the TO are then quenched with a liquid hydrofluoric acid stream. The HF rich gas stream
passes through a multi-stage packed bed scrubber for absorption of HF before being exhausted from the
TO stack. The HF captured by the scrubber system is neutralized by a slaked lime (calcium hydroxide)
system to produce a calcium fluoride (CaF2) solid material that is filtered, recovered, and currently
shipped to an out-of-state landfill.
Performance Test Methods
Two emission test methods were used to measure a number of specific fluorinated compounds. These
include the initial compound of concern noted as GenX (HFPO C3 Dimer Acid) and other compounds that
can be captured and measured by the test methods developed since late 2017. The control of this suite
of fluorinated compounds are a representation (surrogate)for all fluorinated compounds that are being
fed to the TO.

The original test method developed for sampling HFPO C3 Dimer Acid was a modified SW-843 Method
0010. This test method has been used to measure HFPO C3 Dimer Acid and HFPO C3 Dimer Acid
Fluoride emissions from various processes and process areas. However, over the past two years, it was
determined that the Method 0010 was not suitable for higher concentrations of these two compounds
that would be expected at the TO inlet. The second method was a modified Method 18 dry-ice chilled
methanol impinger method. The temperature of this chilled impinger method is sufficiently low to
condense certain vapor phase fluorinated compounds into liquid in the impingers as well as capturing
any semi-volatile fluorinated organic compound. This method works by allowing those fluorinated
compounds to react with the methanol in order to produce extractable and measurable derivative
fluorinated compounds that can be related back to original compounds entering the sampling system.
Although the method was originally developed to capture and quantify hexafluoro propylene oxide
(HFPO) emissions, it was determined that it would be a suitable method for certain other fluorinated
compounds of interest in a limited suite of target compounds. Through the testing program since 2018,
it was also determined that this method was better suited to measuring higher concentrations of HFPO
C3 Dimer Acid and Dimer Acid Fluoride than the Method 0010.
The inlet stream from the monomers and polymers areas were both sampled using the modified
Method 18 sampling systems. These are single point proportional sampling methods where the sample
was extracted from permanent single point probes inserted into each gas stream. The outlet from the
TO and scrubber control system was sampled using both the modified method 18 (for target compounds
other than the HFPO C3 Dimer Acid)and the modified Method 0010(for HFPO C3 Dimer Acid). Since the
outlet emission rates were expected to be very low,the minimum sample times and sample volumes of
the modified Method 0010 of the original method (3-hours sample time per run and 3.0 cubic meters of
sample volume per run) were used to increase the sensitivity of the method. The modified Method
0010 was operated as a standard multi-point traverse, isokinetic sample train while the modified
Method 18 was operated as a single point proportional flow train during the testing. All test runs were
observed by NC DAQ personnel over the two-day testing period.
Sampling Results
The sample train results for each location are shown in the following tables. A review of the test results
indicated that there were no issues associated with the sampling and analysis and that QA/QC data
quality objectives appear to have been met during the testing and laboratory analysis.
It should be noted that analytical results for the outlet of the TO/scrubber combination were non-
detectable by the analytical method for modified Method 18. The results from the Method 0010 for the
HFPO C3 Dimer Acid were above detection threshold for the method and several orders of magnitude
lower than observed in prior testing under the previous control technologies. Therefore,the results
from the outlet testing and analytical methods are shown as being less than the method detection level
(MDL) and the MDL value is used in the mathematical calculation for the destruction removal efficiency
as if the non-detectable value was just below the MDL. This is the most conservative approach for
handling non-detect values from the sampling and analytical process. Non-detects at the inlet are not
included in the calculation and represent a more conservative calculation approach in determining the
performance of the TO system.

Table 1. Summary of Monomer Inlet Test MM18 Target Compounds
Pollutant Run 1 (lb/hr) Run 2 (lb/hr) Run 3 (lb/hr)
H FPO-DAF <1.97 E-01 <3.68 E-01 <6.71 E-02
HFPO Monomer 2.54E+00 1.60E+00 1.57E+00
H FPO-DA 3.22E-03 7.24E-03 7.25E-03
Fluoroether E-1 <2.04E-01 <2.63E-02 <6.95E-02
Carbonyl Fluoride I 8.80E+01 6.39E+01 7.55E+01
Table 2. Summary of Polymer Inlet Test MM18 Target Compounds
Pollutant Run 1 (lb/hr) Run 2 (lb/hr) Run 3 (lb/hr)
H FPO-DAF 8.09E-04 <2.18 E-04 4.10E-04
HFPO Monomer <3.35E-04 <3.47E-04 <2.62E-04
H FPO-DA 1.51E-04 1.29E-04 1.72E-04
Fluoroether E-1 2.65E-03 4.81E-04 2.04E-03
Carbonyl Fluoride <1.13E-03 <1.17E-03 <8.76E-04
Table 3.Summary of TO Stack Test MM18 and MM0010 Target Compounds
Pollutant Run 1 (lb/hr) Run 2 (lb/hr) Run 3 (lb/hr)
H FPO-DAF <3.88 E-05 <4.80E-05 <3.22 E-05
HFPO Monomer <1.75E-06 <2.18E-06 <1.46-06
H FPO-DA 1.20E-06* 9.60E-07* 6.90E-07*
Fluoroether E-1 <2.01E-06 <2.49E-06 <1.67E-06
Carbonyl Fluoride <1.18E-04 <1.46E-04 <9.79E-05
*Results from Modified Method 0010
Table 4.Summary of TO Stack Results for Destruction Removal Efficiency(DRE)
Inlet Stack Control Efficiency
Lb/hr Lb/hr
Run 1 9.06E+01 51.62E-04 _>99.99982
Run 2 7.83E+01 <_2.00E-04 >_99.99974
Run 3 9.55E+01 51.34E-04 >_99.99986
Average 8.81E+01 51.65E-04 >_99.99981
During the test runs,the thermal oxidizer was held at a nominal 1050°C while the processes in the HFPO
VEN,VES, and polymers areas operated in normal representative modes for their areas. During the test,
VES was producing perfluoro methyl vinyl ether(PMVE) and perfluoro ethyl vinyl ether(PEVE),VEN was
producing perfluoro sulfonyl ethoxy propyl vinyl ether(PSEPVE). The polymers production area was
producing the polymer designated as SR. As a practical matter, each area can operate more or less
independently of the other, but all were placed in operation during the performance test to provide the
maximal load to the TO and scrubber system.

Summary and Conclusions
NC DAQ staff members were on site during each day that source testing occurred. DAQ staff observed
the source test teams,the sample recovery and the process operations. Based upon the onsite
observation of the testing and review of the test report, NC DAQ concludes that the testing was
ccnducted in accordance to the modified testing protocol submitted by Chemours and that the
analytical results appear representative of the stack conditions and process operations during the
testing.
In summary,as shown in Table 4,the test results indicate that the TO and associated scrubber system
have met the minimum requirements specified in the Consent Order(99.99%)as well as the
requirements in the Title V permit. If you have any questions concerning these results, please feel free
to contact me at [e-mail] or at(919) 707-8413.
Cc: Central Files—Bladen County
IBEAM Documents-0900009