DEQ-CFW_00086407

QW.DuPont Fluoroproducts
22828 NC Highway 87 W
Fayetteville, NC 28306-7332
October 5, 2007
Mr. Steven F. Vozzo
NCDENR — Division of Air Quality
Fayetteville Regional Office
225 Green Street — Suite 714
Fayetteville, NC 28301
SUBJECT: Suspected Title V Air Permit Deviation
North Carolina Air Permit No. 03735T30
Dear Mr. Vozzo:
This letter is the notification of a suspected permit deviation that occurred with the requirements
specified in Part I Sections 2.1(C)(4)(e) and 2.1(C)(4)(f) of the subject permit. Those conditions
require that the injection liquid flow rate, averaged over a three-hour period, of the Nafion®
baffle plate -type tower scrubber (ID No. NCD-Hdrl) be monitored and recorded.
As will be described below, since it is believed that the NCD-Hdrl scrubber performed properly
throughout the following time periods, and since operating personnel periodically monitored the
scrubber's operation, it is not clear if a permit deviation actually occurred. DuPont requests that
the Division of Air Quality provide regulatory guidance to this question.
During the evening of October 3, 2007, the NCD-Hdrl scrubber injection flow rate was
measured as greater than 20,000 kg/hr, which was unexpectedly high. To determine whether the
scrubber's flow transmitter had malfunctioned, the transmitter was removed from service. The
transmitter was not returned to service for a five hour period, during which time the recorded
three-hour average flow rate dropped below the permitted minimum flow rate of 7,000 kg/hr for
approximately four hours. This was due to the data historian computer receiving an input flow
rate of 0 kg/hr while the transmitter was removed, which then resulted in the calculated 3-hour
average ultimately decreasing to less than 7,000 kg/hr.
The morning of October 4, 2007, the transmitter was again removed from service due to the
continued high injection flow rate. This caused the recorded three=hour average injection flow
rate to drop below the permitted limit for approximately one hour. Within an hour of this
occurrence the processes that vent to the NCD-Hdrl scrubber were shutdown.
DEQ-CFW 00086407

Mr. Steven F. V-ozzo
NCDENR — DAQ
October 5, 2007
Page 2 of 2
It was subsequently found that the air to the injection liquid's flow control valve had been
inadvertently turned off. Since the flow control valve is a "fail-safe normally -open" valve that
causes the valve to open fully without the actuating air, the injection liquid's flow rate was the
maximum the pump can deliver, or greater than 20,000 kg/hr throughout this period.
The scrubber continued to operate properly, albeit with a greater than normal injection flow rate,
during both of these periods as verified by operating personnel who periodically monitored the
scrubber pump's performance while the flow rate transmitter was out of service. Therefore it is
believed that the actual injection flow rate remained above 20,000 kg/hr throughout this period,
and as such there were no excess emissions.
An incident investigation will be conducted to determine how the actuating air valve became
closed. Also, DuPont will consider procedural and physical changes to the operation of both the
NCD-Hdr1 and NCD-Hdr2 scrubbers to prevent recurrence of this incident.
The DuPont Company — Fayetteville Works' responsible official, Karen Wrigley, is out of the
country until October 10, 2007, and as such cannot sign this written report as specified by Part I
Section 3(I.A.)(3)(a) of the subject permit.
By my below signature, I certify that I believe the information contained in this letter is true,
accurate, and complete.
cc: Mr. Robert Kennedy, NCDENR Division of Air Quality, FRO
DEQ-CFW 00086408