AQ_F_0600015_20210909_CMPL_Fac-Ltr

. %-_.. a RECEIVED
� S I B E L C 0
a -4�
..1
S E P 1 5 2021
Sibelco North America, Inc.
107 Harris Mining Co Road•Spruce Pine,NC 28777 DWon of Air OUSMy
(PHONE)828/765-4251 Asheville Regional Office
eptem er 9,2021
CERTIFIED MAIL
RETURN RECEIPT REQUESTED
Mr. Brendan Davey,P. E.
Regional Supervisor
Division of Air Quality;NCDEQ
2090 U. S. Highway 70
Swannanoa,North Carolina 28778
Subject: Scrubber Monitoring Parameters
Sibelco North America, Inc.—Schoolhouse Facility
Spruce Pine,North Carolina,Avery County
Air Permit No. 04000R22
Dear Mr. Davey:
In response to your letter dated August 23, 2021 regarding the compliance inspection conducted by Mr.
Amro Ali on August 4, 2021, please note the following comments. I apologize for my delay in response
as, due to mailing and courier delays, I did not receive your letter until yesterday morning September 8,
2021.
First, regarding the liquid injection rate of the fluid bed dryer scrubber. From my discussions with the
Environmental Supervisor, we determined that Wet Scrubber WS-01 did have sufficient flow greater than
26 gpm during the inspection. This type of flow meter has a tendency to become clogged due to the water
containing particulates at times. We replaced the flow meter with a different style that is less susceptible
to clogging. Once the flow meter was replaced, the flow indicated around 28 gallons per minute, well
above permitted levels with no other changes performed by maintenance. Thus, the liquid injection rate
was indeed maintained above the required minimum at all times. Wet Scrubber WS-01 was merely noting
low reading due to particulate build up in the vortex of the sensitive flow meter. We hope this new type
of flow meter will require less maintenance over time.
Secondly, regarding the pressure drop meters. Please note Wet Scrubbers WS-01 and WS-02 contain two
(2) pressure drop gauges on each control device. The first is located at the scrubber and is a manual
Dwyer Magnehelic gauge. The second is an electronic meter that feeds readings back to the Schoolhouse
HMI system (computer operating system). Due to the location of the manual meters, the reliance of the
Dwyer instruments are not used to make the official pressure drop readings for the compliance
documentation. Attached is a screenshot of the readings as they are transmitted to the HMI system.
Unfortunately, on August 4 we experienced a network outage and were unable to show Mr.Ali the results
on the HMI screen. The daily pressure drop readings were logged later that day once the network was
restored.

Mr. Brendan Davey
Page 2
Sibelco strives to comply with environmental regulations and are very proactive in maintaining
compliance at our facilities. We highly regret these issues have occurred as the flow meters are
historically cleaned or replaced as soon as possible.
To alleviate this issue, we have revised the operator logs to note mandatory values and require an
acceptable value before letting the operator proceed with data entry. Otherwise, the operator is required
to initiate a corrective action. All current operators and any new operators performing monitoring will be
thoroughly trained to record monitoring data correctly and to document future work orders to replace
required monitoring equipment as quickly as possible.
Finally, I would like to express that as normally observed, there were no visible emissions occurring from
any emission sources or control devices.
If you have any questions regarding this matter or require further information, please do not hesitate to
contact me directly.
Regards,
Rick Singleton
Production Manager
Schoolhouse Plant
rick.sin leton(a�sibelco.com
828-765-4251

New WS-01 flow meter
vT;
g
i
i
i
g

Schoolhouse HMI screen shot showing Pressure drop on scrubbers
co IFunF coNrRot ❑ n021ollvectory
sLarn
SIBEL ❑
� 2:02:53 PM
"FILTERED" to Atmosphere
WATER Local
�_ FA-07
SCRUBBER WS-03 FUME C0N7ROL
EXHAUST FAN TREND
0.0 gpm
WS-03
BULK STORAGE
0.0"WC ACID SCRUBBER to Fluoride Trench
6.8 pH
~s smrv8 PU-37 Ws-01
DR-01 DRYER
BULK STORAGE WET SCRUBBER
WS-03SUMP SUMP PUMP 30.0 gpm
to Atmosphere
Difl,Pressure
0.707 "WC
WS-02 Running
ji ACID ROOM 49.0 amps
WET SCRUBBER 60.0 hZ
pm Faun
29.s to Atmosphere Exhaust Fan s'�Kw
0.6"WC
8.0 pH
Local
Local FA-06
Pu31 SCRUBBER WS-02
SCRUBBER WS-02 EXHAUST FAN
RECIRC PUMP