United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Research Triangle Park NC 27711
Research and Development
EPA-600/S7-83-046 Dec. 1983
Project Summary
Preliminary Environmental
Assessment on Formcoke
Cokemaking Process
D. W. Coy, C. C. Allen, and B. H. Carpenter
A preliminary environmental evalua-
tion and assessment of formcoking has
been made. The work is based on readily
available literature sources, a plant
visit, formcoke plant proposal and
feasibility study data, and discussions
with engineers and operators involved
with formcoking. Material balances,
calculations, and engineering judge-
ment have been used to convert existing
data and information into a form that
can be used to compare environmental
discharges between formcoking and
conventional by-product coking. The
results of those comparisons are pre-
sented. The lack of adequate environ-
mental data on formcoking is noted
This Project Summary was developed
by EPA's Industrial Environmental
Research Laboratory, Research Triangle
Park. NC. to announce key findings of
the research project that is fully
documented in a separate report of the
same title (see Project Report ordering
information at back).
Introduction
This report, prepared in response to a
request from the Department of Energy
(DOE), is a preliminary environmental
assessment of formcokemaking. It was
prompted by a proposal from Inland Steel
to DOE, soliciting government-funded
assistance for the design and construc-
tion of a new formcoke plant. The depth of
the assessment was limited by the time
available to complete the work, and
insufficient time to do any sampling and
analytical work. The reported conclusions
are based on data existing when the study
began. Material balances, calculations,
and engineering judgement were used to
convert existing data into a form that
could be used to compare environmental
discharges between formcoking and
conventional coking.
After completion of this report, DOE
recommended that Congress provide
initial incremental funding for detailed
design of the Inland Steel formcoke plant.
While initial funding was approved in
Congressional committee action, the
project never received funding considera-
tion before the full House or Senate.
Inland officially withdrew its proposal in
1981.
Summary
A preliminary environmental evaluation
and assessment of formcoking has been
made. The work is based primarily on
readily available literature sources; a visit
to the FMC Corporation formcoking plant
in Kemmerer, WY; data available in
Inland's proposal; data from a feasibility
study of the proposed plant by Davy-
McKee Corporation; and discussions with
various engineers and operators involved
with formcoking.
The FMC formcoke plant consists of a
coal preparation section for crushing and
sizing incoming coal, a fluid-bed pyrolysis
section to distill volatile matter and
produce a char, and a briquetting and
coking section to shape and finish the
product. The fluid-bed pyrolysis section
receives coal crushed to minus 4 mesh.
The initial fluidized bed, the catalyzer,
drys the coal at 149°C and partially
oxidizes the coal to reduce agglomerating
properties. The conditioned coal then
proceeds to the carbonizer where it is
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heated to 480°C to break the coal into tar,
char, gas, and water. The partially
devolatilized char then is processed in the
calciner at 815°C to release remaining
volatiles and produce the solid reactive
calcinate.
After cooling, the calcinate is mixed
with dehydrated tar and pressed into
briquettes. The briquettes are cured in an
oven at 232°C. The cured briquettes are
then coked in a shaft kiln at temperatures
above 800°C.
The fluidizing gas in the pyrolysis
section at FMC is air. Waste gas produced
in this section has a relatively low heating
value, 5.6 MJ/m3 (150 Btu/ft3). The
proposed Inland plant may operate with
air also, or alternatively it may operate
with a fluidizing gas enriched with
oxygen and steam to produce a by-
product gas with higher heating value,
13.0 MJ/m3 (350 Btu/ft3).
The existing FMC plant was examined
to identify the waste streams leaving the
plant and the pollutant levels in those
strems. Because of the limited time
available to complete the project, it was
necessary to depend on pollutant data
available from test work previously
completed. These available data were not
comprehensive; as a result there were
many data gaps.
The proposed plant description in the
Inland proposal was compared to the
existing plant. Differences in the process
equipment and pollution control facilities
were examined. In particular, the proposed
plant would have been about four times
larger than the existing plant, and been
processing an Illinois (instead of a
Wyoming) coal. With Illinois coal the
process would not have produced enough
tar for binder. Supplementary tar would
have had to be processed and added.
Inland planned to design the plant to
operate in either an air mode similar to
FMC or an oxygen/steam mode that
would have produced a higher heating
value by-product gas stream than at FMC.
In either mode the gas would have been
recovered for other plant uses.
In the gas recovery process more
efficient paniculate removal was expected
in the Inland plant than is achieved at the
FMC plant. Since gas is not desulfurized
at FMC, whereas a Stretford system was
proposed for the Inland plant, SO*
emissions from the proposed plant would
have been much lower. The FMC plant
discharges wastewater to a holding
evaporation pond. The proposed Inland
facility final wastewater would have been
treated in a publicly owned treatment
plant; pretreatment in the form of
ammonia and cyanide stripping was
planned, with the recycled wastewater
stream cooled by noncontact water
streams.
The adequacy of proposed pollution
controls for the proposed Inland installa-
tion was also studied. (Note that the final
plant design was not available, and the
proposed equipment was little more than
conceptual.) Plans for controlling particu-
lates and S0> offer the potential for
compliance with proper specifications
and selection of design parameters.
Present NOx regulations appear to affect
none of the proposed plant sources.
Ammonia and cyanide incineration,
however, was expected to produce more
NOx than would be allowed from the
smallest source regulated in Indiana.
Ammonia recovery could be practiced to
reduce NOx emissions. No air pollution
standards for polycyclic organics currently
exist, and no data were available to
analyze quantities of potential organic
emissions from formcoking.
With respect to potential discharges
from the proposed Inland plant, waste-
water samples were requested from the
FMC plant, but they were not received in
time for analysis and inclusion in the
report. In qualitative terms many of the
components present in conventional
coking wastewater were expected to be
present in formcoking wastewater, but
quantities may be different. Since
specific wastewater treatment equipmenl
has not been selected, an assessment of
the potential for compliance with pre-
treatment standards has not been pos-
sible. Also, plans for solid waste handling
were not defined at that time, again
preventing an assessment of the potential
for compliance.
Finally, estimated environmental dis-
charges from formcoking were compared
with those estimated for conventional
coking. Table 1 summarizes the results of
the comparisons. No direct measurement
of polycyclic organic matter (POM)
emissions was available from formcoking
for comparison with conventional coking.
Worker exposures to benzene-soluble
particulates have been measured at the
FMC plant. In general the FMC measure-
ments show lower worker exposures
than have been found in conventional
coke plants. This comparison suggests
that POM emissions may also be lower
for formcoking.
Not shown in the numerical compari-
sons is the expected greater ease of
maintaining control of air pollution for
formcoking as compared to conventional
coking. Control of air pollution from the
batch conventional coking process (par-
ticularly hazardous organic pollutants) is
highly dependent on work practice and
also tends to deteriorate with coke battery
age as a result of battery dimensional
Table 1. Comparison of Environmental Discharges — Conventional Versus Formcoking
Environmental
discharge
Particulates
SO,
NO,
from NH3
from other combustion
Wastewater
Sludge and solid residues
POM fas indicated by B(a)P)
Occupational exposure to
benzene solubles
Conventional coking
kg/ Ma coke
0.7-7.5"
2.2
13C
—
550-1,460
(Including
by-product
recovery)
38"
0.004
150-5OOug/m3
Formcoking
kg/Mq coke
1.1"
2.2
4-14c'a
—
630- J. 400
Air mode
1.410-2.210
steam/ Oz mode
(Including
by-product
recovery)
29.8'
Air mode
24.7'
steam/Oz mode
No data
50-161 ug/rrf
"Low value, for a well controlled battery for all paniculate sources, is an ideal case.
^Conservative estimate; could be decreased if necessary.
cZero if recovered instead of incinerated.
aThere are indications that the lower-carbonization-temperature formcokeprocess will favor lower
formation of ammonia.
eIncludes coke breeze (~ 36 kg/Mg) much of which is used as a low value fuel rather than as coke.
'Does not consider possible reuse of formcoke sludges.
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changes. These factors are not expected to
play as big a role in air pollution control
for the continuous formcoking process.
For normal operations, paniculate
emissions are expected to be about the
same for formcoking as for a well
controlled coke oven battery. A well
controlled battery for all paniculate
sources is an ideal case that may be
difficult to achieve because of the batch
nature of the process. SOX emissions are
expected to be about equivalent. Since
ammonia is usually not incinerated for
conventional coking, the actual and
proposed formcoking will have higher
NOx emissions from this source. Alterna-
tively ammonia could be recovered from
formcoking in the same manner as for
conventional coking.
In the air mode, wastewater quantities
will equal conventional coking. In the
operating mode (steam/oxygen) with
high heating value gas recovered, the
formcoke process is expected to generate
up to 50 percent more wastewater for
treatment than conventional coking
(when compared on the basis of recovering
benzene from both processes). Presum-
ably the wastewater from each can be
treated to give the same discharge
quality. For plants that might have to
provide full wastewater treatment instead
of pre-treatment followed by discharge to
a publicly owned treatment plant, the cost
could be a significant impact to overall
process economics.
Sludge/solid waste quantities for
which no uses have been identified are
also higher for formcoking than conven-
tional coking. Ultimate disposal of the
sludge/solid waste is a key issue. In
conventional coking an analogous solid
by-product is coke breeze. In most cases
coke breeze is reintroduced to the iron
and steelmaking process or sold. It is not
known if calcinate thickener sludge could
be handled similarly.
A full assessment of formcoking would
necessarily examine trace element
emissions (heavy metals, etc.). Though no
direct measurements have been made on
a formcoke plant, some data from
gasification processes with similar
fluidized-bed operations were reviewed.
The data are presented not to say a
problem with trace elements exists, but to
establish the importance of a more
thorough investigation.
Conclusions
The study led to several conclusions:
1) Formcoke production will eliminate
many sources of hazardous air emissions
which are present in conventional coking
and are difficult to effectively control. The
formcoking process is more amenable to
air pollution control in that there are
fewer potential emission sources and the
age deterioration of process equipment is
not as severe as that which occurs in
conventional coke batteries.
2) Formcoke production has the poten-
tial of significantly reducing worker
exposure to carcinogenic air emissions,
when compared to conventional coking.
3) Formcoking is expected to produce
the same amount of (or up to 50 percent
more) wastewater to be treated and
sludge/solid waste for which it is
desirable to find uses.
4) With formcoking some trace element
and polycyclic organic matter concentra-
tion may occur, in the recycled wastewater
similar to continuous coal conversion
processes. Data are insufficient to
determine the extent of buildup and
identify satisfactory wastewater treat-
ment technology.
5) Existing data are not sufficient for a
complete environmental assessment of
formcoking.
D. W. Coy, C. C. Allen, and B. H. Carpenter are with Research Triangle Institute,
Research Triangle Park. NC 27709.
Robert C. McCrillis is the EPA Project Officer (see below).
The complete report, entitled "Preliminary Environmental Assessment on
Formcoke Cokemaking Process," (Order No. PB 83-259 713; Cost: $10.00,
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
ftUS GOVERNMENT PRINTING OFFICE 1984-759-015/7258
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