xc/EPA
United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S2-82-066 August 1982
Project Summary
Development and
Demonstration of Concepts for
Improving Coke-Oven
Door Seals: Final Report
A. 0. Hoffman, A. T. Hopper, and R. L Paul
The report discusses the design,
laboratory scale tests, construction, and
field tests of an improved metal-to-metal
seal for coke-oven end doors. Basic fea-
tures of the seal are: high-strength tem-
perature-resistant steel capable of 3
times the deflection of current seals
without permanent deformation; no
backup springs and plungers and the at-
tendant requirement for manual inser-
vice adjustments,' seal installed to con-
form to the jamb profile; seal lip height
reduced to give 8 times the inplane flexi-
bility; and compatibility with existing
coke batteries and door handling
machines. Field tests on operating 4 and
6m batteries proved the soundness of
the concept along the straight vertical
sides of the door. However, an unfore-
seen force combination in the four cor-
ners resulted in a net force acting to lift
the seal corners away from the jamb, re-
sulting in unacceptable leakage at each
seal corner. Various schemes were eval-
uated empirically in an attempt to under-
stand and solve the problem. A modified
design to eliminate the problem and re-
duce fabrication cost is proposed. Inland
Steel Company plans to build and test
the modified design at its own expense.
This was a jointly funded EPA/American
Iron and Steel Institute project.
This Project Summary was developed
by EPA's Industrial Environmental Re-
search Laboratory, Research Triangle
Park, NC, to announce key findings of
the research project that is fully docu-
mented In a separate report of the same
title (see Project Report ordering infor-
mation at back/.
Project Origin
In 1975 Battelle completed a project
entitled "Study of Concepts for Minimiz-
ing Emissions from Coke-Oven Door
Seals." This project was jointly spon-
sored by the Industrial Environmental
Research Laboratory of EPA and the
American Iron and Steel Institute (AISI).
The results and recommendations of
the 1975 study were accepted by both
sponsoring organizations and late in
1976 Battelle was awarded research
contracts (with EPA and the AISI) deal-
ing with development/engineering/lab-
oratory evaluation of the recommended,
upgraded metal seal. The results of this
effort were accepted by the sponsors
and funding was made available to com-
plete Phase III of the program which con-
sisted of fabrication and field demonstra-
tion of the recommended seal design/
material.
This Report
This report summarizes the entire ef-
fort to develop an upgraded, retrof ittable,
metal coke-door seal. "Upgraded" here
is defined as having significantly im-
proved performance in emission control
and operation.
-------
Not included in this report are results
of a major effort to prevent/minimize
warpage of coke-oven jambs by changes
in the jamb design and materials. This
work was, however, reported in the EPA
report, "Development and Demonstra-
tion of Concepts for Improving Coke-
oven Door Seals: Interim Report," EPA-
600/2-78-189 (NTIS PB No. 286 628),
August 1978.
The Recommended Seal Design/
Material
The recommended seal design was
the result of finding a best "fit" as eval-
uated by a long list of criteria and specifi-
cations. In a systematic approach, each
criterion had to be considered, but the
two major influences on the design were
(a) a general specification by the AISI
and EPA, and (b) a criterion strongly de-
sired by Battelle researchers.
The major specification was that the
new seal be retrofittable, i.e., the new
seal would be a replacement for existing
seals without modification of the doors
or the door-handling equipment. This
also meant that the recommended seal
had to "handle" or accommodate all (or
nearly all) of the jamb and the door warp-
age problems that exist at operational
plants. Seals are attached to doors and
the profile congruency of the door with
the oven jamb can be poor due to past
warpage and heat effects.
The criterion desired by Battelle per-
sonnel was that the recommended design/
material should eliminate the need for
numerous, manual seal-adjustment de-
vices associated with all existing seals.
With about 25,000 coke-oven doors in
operation, each with about 20 manual
seal-adjustment devices, the theory is
that at times workers climbing ladders or
scaffolds would adjust 500,000 de-
vices to improve emission control. Bat-
telle researchers were skeptical about
the performance of the adjustment de-
vices and the availability of the time and
skill to manipulate them.
The general approach to an upgraded
seal was to increase the seal flexibility in
every way possible while also increasing
its strength and heat resistance. This ap-
proach resulted in the recommended de-
sign shown in Figure 1.
The design/material elements leading
to increased flexibility and strength are:
1. The height of the contacting edge
[(A) in Figure 1 ] was lowered to a
9.5-mm height (from 19 mm) to in-
crease the flexibility of the edge
along the jamb by a factor of 8. This
increased flexibility allowed the
Sealing Ring (B)
Figure 1. Cross section of a suggested coke-oven seal.
vertical seal edge to maintain con-
tact with the jamb in spite of curva-
tures in the jamb surface and the
uneven surface of the seal edge.
. The main spring element [(B) in Fig-
ure 1] was switched from 304
stainless or a corrosion-resistant,
low alloy steel to a high-strength,
high-temperature spring alloy. Bat-
telle recommended that the first
demonstration seals be made of
age-hardened Inconel X-750. In
laboratory tests at 426 °C (800 °F),
Inconel X-750 tolerated three times
the amount of seal deflection dur-
ing simulated door latching before
plastic distortion by creeping was
encountered. Increased seal deflec-
tion is desired to (a) absorb minor
changes in door and jamb profiles
without the need for adjustments,
and (b) keep an evenly distributed
force pressing the seal edge
against the jamb.
3. Changing the width of the spacers
[(C) in Figure 1] along the door
made it possible (during original
seal mounting) to bend the entire
seal to make the profile of the seal
edge match the general profile of
the jamb. This element of flexibility
was introduced to make it possible
to realign the seal edge and jamb
profile in instances where the door
and jamb profiles are particularly
incongruent.
This design eliminated the need for seal-
adjustment devices (and backup springs)
-------
pressing in point loading against the out-
board side of the seal.
Demonstration Seal Fabrication
Two of the criteria for judging seal
designs were (a) whether the design was
amenable to mass production methods,
and (b) whether the machining during
fabrication could be eliminated. For the
design presented, Battelle recommend-
ed (1) roll forming the seal shape rather
than one-at-a-time brake forming, and
(2) hydroforming the corners rather than
the cut-fit-weld-machine fabrication me-
thods now being used.
Further complications were intro-
duced by (1) the requirement that de-
monstration seals should be obtained
from experienced seal fabricators, rather
than jobbing fabrication to different
shops; and (2) introduction of a seal-
corner design that could be fabricated
only in a hydroforming operation.
Eleven months after sending out re-
quest for quotation seals, four seals
were delivered to the Bethlehem Steel
coke plant in Lackawanna, New York.
Results of the Seal
Demonstration Efforts
The recommended seal design/material
was tested at Bethlehem Steel's coke
plant in Lackawanna, New York (6-m
Wilputte battery) and at Republic Steel's
coke plant in Youngstown, Ohio (4-m
Koppers batteries).
At Lackawanna, the usefulness was
demonstrated of taking simple measure-
ments of the variation in distance be-
tween the jamb and door (along its
length) and then installing spacers under
the new seal to bring the seal edge into
congruency with badly warped jambs. In
one instance it was necessary to put a
1 9-mm (%-in.) steel bar under the top
horizontal portion of the seal to bring the
profile of the seal into alignment.
Zero leakage, increased flexibility, and
no manual adjustments were demon-
strated (for months) along the 6-m ver-
tical sides of the seal, as expected.
However, all four seals put into opera-
tion unexpectedly released emissions
through gaps at each corner. This prob-
lem persisted even after reworking one
seal to eliminate variations in the flat-
ness of the seal edge. It was deduced
that the corners were "lifting off" the
jamb; i.e., the corners were reacting to
forces that act to cause a slight gap at
the corners during seal deflection. This
lift off effect was confirmed at Republic
Steel during tests using a 4-m seal forced
against a flat machinist table.
The fact that corners on seals can re-
act counter to a desired pattern was not
new—U.S. Steel research personnel had
told Battelle about "corner lifting" they
had encountered on standard seals. What
was obvious was that (a) the design
changes made to avoid this potential
problem were not successful in full-scale
operation, and (b) that Battelle's labora-
tory work on parts of the seal did not
model the reactions in complete seals.
Experiments at Republic Steel indicated
that the seal lip was not part of the prob-
lem and that some method had to be
found to relieve the "bunch-up of
metal" that occurs during seal deflec-
tion in the flat portion of the seal in the
corners.
The Modified Seal Design
Project originators did not anticipate
that a considerable amount of problem
solving would be required after getting
the first demonstration results. Although
continued analytical work was consid-
ered (modelling and strain gauge testing
on a full-scale seal), the last emphasis in
the project was to consider the range of
design changes that could provide ah
empirical solution to the corner problem.
Out of this approach came a modified
seal design (not yet tested). This modi-
fied design is shown in Figure 2.
The major elements are:
A— a flat strip, cantilever-spring re-
placement for the formed S-shape
used in the original design.
B— a heavy-section, carbon-steel,
angle-iron seal holder.
C— a demountable seal-edge angle
bolted or welded to the seal ele-
ment (no machining required).
It is recommended that the spring por-
tion of the seal be made of 1 7-4 PH
stainless steel, rather than Inconel
X-750. This lower priced alloy was not
included for consideration in the original
evaluation because it is difficult to form,
but all forming is eliminated in this
design. It is expected that this seal can
be built by steel companies.
For an empirical approach to a solution
of the corner problem, it is suggested
Door Back
Figure 2. Modified seal design.
« U.S.aOVEBNMINTWIINTIM30FFIM:1»U-S59-Ol7/0784
-------
that the strips making up the main por-
tion of the seal only be butted at the cor-
ners, not welded. This leaves a space or
separation in the corner that (a) makes
the corner relatively flexible, (b) permits
consideration of corner backup (springs)
outboard of the corner to force the cor-
ner against the jambs, (c) may minimize
some of the stress generation in the cor-
ners during deflection, and (d) could in-
troduce a built-in emission problem in
the corners. To prevent emissions
through the spacings, it is suggested
that this space be closed with a cover
strip (or foil) attached outboard of the
corner.
Present Status of the Modified
Seal
Inland Steel has volunteered to engi-
neer/fabricate/test and oven-demon-
strate one seal of the modified design. At
this time, engineering is complete and
fabrication is in progress.
A. 0. Hoffman, A. T. Hopper, and R. L. Paul are with Battelle-Columbus Labora-
tories, Columbus, OH 43201.'
Robert C. McCrillis is the EPA Project Officer (see below).
The complete report, entitled "Development and Demonstration of Concepts for
Improving Coke-Oven Door Seals: Final Report," (Order No. PB 82-230913;
Cost: $12.00, subject to change} will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield. VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Industrial Environmental Research Laboratory
U. S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
Postage and
Fees Paid
Environmental
Protection
Agency
EPA 335
Official Business
Penalty for Private Use $300
US tNVIR PROTECTION
REGiON 5 U8RAKYT
230 S DEARBORN STREET
CHICAGO 1L 606U4
------- |