DAQ-2024-011166

DEPARTMENT OFTHE AIR FORCE
75TH CIVIL ENGINEER GROUP (AFMC)
HILL AIR FORCE BASE UTAH
17 April2024
Amanda Burton
Chief, Environmental Branch
75th CEG/CEIE
7290Weiner Street
Hill Air Force Base Utah 84056-5003
Director
Utah Division of Air Quality
Attention: Compliance Section
P.O. Box 144820
Salt Lake City Utah 84114-4820
Dear Director
UTAH OEPARTMENT OF
ETWIRONMENTAL QUALITY
il"i' tj ' i
l)an d
DIVISION
del\ lered
OF AIR OUALITY
Hill Air Force Base (AFB), in accordance with R307-107-2, is submitting this detailed
written description of a breakdown to a24.49 MMBtU/hr rental boiler permitted in Approval
Letter DAQE-GNl0l2l0289-23. Initial notification of this breakdown was provided within 24
hours of breakdown via email at ll,23 on I I April2024. The boiler experienced a mechanical
failure of the flue gas recirculation (FGR) valve on l0 April2024, thus impacting the boiler's
ability to meet the 9 ppm NOx design of the boiler.
On 10 Apil2024, a power supply intemrption to the temporary rental boilers at building
1286, caused both boilers, AQUIS IDs 45444 and 45445, to shut down unexpectedly. At
approximately 1400 hours, AQUIS ID 45445 was restarted. Efforts to restart AQUIS ID 45444
by operators utilizing typical operating procedures was unsuccessful. The contractor responsible
for maintaining the rental boilers was contacted and arrived at 1600 hours on l0 Apil2024 and
began their evaluation of AQUIS ID 45444. The contractor identified the flue gas recirculation
valve, which is a critical aspect of the design of the boiler to meet the 9 ppm NOx limit, had
seized in the closed position and the actuator could not open the valve.
Boiler AQUIS ID 45444 was turned on at 1800 hours on 10 April2024 at a reduced
operating load of 13% while waiting for the replacement part and repairs. The unit was required
to operate during the breakdown episode to ensure adequate steam pressure was provided to
areas impacted by the two rental boilers since limiting operations to one boiler was insufficient
for the needs of the system. The unit was shut down at 0700 hours on Friday 12 April 2024 after
receiving the replacement part to begin repair efforts. Efforts to repair the unit were completed
successfully and the unit retumed to normal operation by 1300 hours that day. It was ultimately
determined that the cause of the malfunction was due to a metal burr causing the FGR valve to
seize. The boiler operated for a total of 37 hours with the malfunctioning FGR valve.
REVIEWED Initials: Date: Oct 24, 2024Compliance Status: OK File # 10121 (B2)
The boiler has preventative maintenance conducted each month. The issue that caused
the malfunction would not be typicatly addressed tturing these preventative maintenance actions
as it is not a common malfunction and could not have been foreseen. A replacement FGR valve
is onsite in the event this type of repair should be needed in the future. All repairs were made to
the unit as quickly as practicable. The unit was nm at the minimum load possible to minimize
excess NOx emissions. Total NOx emissions and excess NOx emissions have been calculated
and are listed in the table below. The rental boilers are not owned by Hill AFB and are expected
to be taken out of service after the2023 -2024 heating season.
If you have any questions or would like to discuss this issue further, my point of contact
is Dr. Erik Dettenmaier 75 CEGiCEIEA, at (801) 777-0E88 or [e-mail],mil.
AMANDA C BURTON, NH.III, DAF
Chief, Environmental Branch
Sincerely