DEQ-CFW_00087442

DuPont Fluoroproducts
22828 NC Highway 87 W
Fayetteville, NC 28306-7332
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DuPont Flu®r®pr®ducts
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June 25, 2004
Dr. Donald R. van der Vaart, P.E.
NCDENR — Division of Air Quality
Permitting Section
1641 Mail Service Center
Raleigh, NC 27699-1641
SUBJECT: DuPont Company — Fayetteville Works
Air Quality Permit No. 03735T26
Facility ID: 0900009
Request for PSD Applicability Determination
Boiler No. 1 (ID No. PS-1) Maintenance Project
Dear Dr. van der Vaart:
This letter is a request for the North Carolina Division of Air Quality (DAQ) to make a
PSD applicability determination with regard to a future maintenance project on the Boiler No. 1
(Title V Permit ID No. PS-1) at the DuPont Company — Fayetteville Works.
Specifically, we request that DAQ determine whether the maintenance activity detailed in
this letter would be considered as routine maintenance, repair, and replacement pursuant to the
Prevention of Significant Deterioration (PSD) permitting program.
In making PSD applicability determinations, DAQ has adopted the EPA process which
uses a case -by -case determination weighing (1) the nature and extent, (2) purpose, (3) frequency,
and (4) cost of the work, as well as other relevant factors to arrive at a common sense finding.
In the following, DuPont presents information to assist DAQ with this four -factor
determination test. We believe that you will agree that the future boiler maintenance project
would be considered to be routine maintenance, repair, and replacement.
Nature and Extent of the Project
DuPont intends to replace all 1,200 water tubes, and the steel exterior shell and the
refractory/insulating materials surrounding the tubes, on the Boiler No. 1. These parts of the zi
boiler are all in -kind replacements, resulting in no additional steam generation capacity.Pas
e
replacement of the exterior shell and refractory are required due to their destructive remov ;
the means of accessing the water tubes. The original steam and mud drums, and all ancaxy�'
equipment required for this boiler, are not involved in this repair. Following this proje the
Boiler No. 1 will be able to operate at its original design specification.
E. I. du Pont de Nemours and Company
Printed on Recycled Paper
FL-4 Rev.6/99
DEQ-CFW 00087442

Dr. Donald R. van der Vaart
NCpENR Division of Air Quality
June 25, 2004
Page 2 of 3
Purpose of the Project
The purpose of the boiler maintenance project is to restore the steam production capacity
of the Boiler No. 1 to its nameplate design capacity of 139.4 MM-BTU per hour.
It is important to note that this project neither will increase the steam production capacity
by Boiler No. 1, nor will it extend the useful life of the boiler.
Frequency of the Project
Boiler No. 1 is a 1969 vintage package boiler designed to. burn No. 6 fuel oil. This boiler
has been in operation since 1970, and provides virtually all of the steam needed for the operation
of the DuPont — Fayetteville Works facility. The Boiler No. 1 has been retubed several times. In
recent history, the boiler was completely retubed in 1992, and again in 1998. The subject
maintenance project calls for the complete retubing of this boiler. Therefore, the boiler has been
recently retubed at a frequency of once every six years.
Package boilers by their nature are susceptible to maintenance problems due to the high
heat input relative to larger field erected units and their tight flue gas passages. Both of those
features are necessary in order to provide a lower installed cost unit that can be assembled in a
shop and shipped to the final user location. The higher heat input rate translates into potential
tube problems when waterside conditions are not perfect, which they rarely are. The tight flue
gas passages in the convection pass cause deposition of ash in those passages and an inability to
thoroughly clean that out with sootblowing due to (1) the sootblower's steam simply cannot
penetrate far enough to be totally effective, and (2) there is a practical limit to the number and
location of sootblowers.
Over time when firing No.6 fuel oil, the convection passes will tend to fill up with ash and
sulfur compounds. The nature of No.6 oil ash is such that it absorbs moisture when cool
(hygroscopic), and moisture reacts with the sulfuric ash to form sulfuric acid. Since the boiler is
constructed of carbon steel, the sulfuric acid deposits attack the outside of the tube surfaces,
causing corrosion and eventual tube leaks.
Therefore, simply by design, package boilers firing No.6 fuel oil are expected to require
tube and casing section replacement over their operating lifetime due to normal corrosion and
internal tube surface conditions with the high heat input per unit surface area. It is not
uncommon to see some level of tube replacement on a several year frequency, the frequency and
extent of replacement will depend on actual service conditions for the particular boiler as well as
the specific unit design characteristics. There is typically no damage to the steam and mud
drums of a package boiler over time or with the tube and casing repair. Typical steam side
operating conditions of industrial boilers are not hot enough to cause long term metallurgl
deterioration of the drums. Therefore, there is no real limit to the lifetime of a boiler per sl5as
long as proper maintenance and selective tube replacement is conducted. Package boilers4ith
good maintenance and operating practices can be expected to exceed fifty (50) years of seiice:
However, if proper operation and maintenance is not maintained, boiler conditions 1ould?
deteriorate significantly so reliability and safety are impacted and total replacement becomes: 4
DEQ-CFW 00087443

Dr. Donald R. van der Vaart
NCDENR Division of Air Quality
June 25, 2004
Page 3 of 3
more economical choice than repair of the old unit. Therefore, retubing of the DuPont —
Fayetteville Works' Boiler No.l is considered expected routine maintenance for that boiler
operating under its specific conditions. This repair will simply return the boiler to its reliable
operating condition and not change its original design capability.
Based on the above, the 34-year old Boiler No. 1 is expected to continue to operate for at
least another sixteen (16) years to reach its minimum life expectancy of fifty (50) years.
Cost of the Project
The Boiler No. 1 maintenance project is expected to cost $594,824, which is less than
9.3% of the projected $6,400,000 cost of a new boiler.
Enclosed you will find both the cost estimate package for the boiler retube and the cost
estimate package for the boiler replacement.
Summary
Based on the statements made in this letter and the multi -factor analysis presented above,
DuPont believes the Boiler No.1 maintenance project should be considered "routine
maintenance, repair, and replacement", and as such, pursuant to 40 CFR 51.166(b)(2)(iii)(a), this
project does not constitute a "physical change or change in the method of operation."
If you need additional information or would like to discuss this matter further please
contact me at [phone].
Environmental Manager
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Enclosures
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cc: Mr. Steven F. Vozzo - Fayetteville Regional Office
DEQ-CFW 00087444