United States
Environmental Protection
Agency
Industrial Environmental Research ,
Laboratory
Cincinnati OH 45268
Research and Development
EPA-600/S2-82-013 Oct. 1982
Project Summary
Assessment of Waste Fuel
Use in Cement Kilns
Dougtes8!*. Hazelw'ood, Francis J. Smith, and Ellis M. Gartner
U.S. Environmental Protection Agency
Region V, Libnry xX
230. South Dt-jfborn Street ^'" ^
Ctafeago, Illinois 6060.4 .X
This study was initiated to document
current knowledge concerning the use
of waste fuels in cement kilns. Techni-
cal and economic factors affecting the
use of cement kilns to destroy waste
materials are reviewed. The recom-
mendations derived from the study
propose additional work required to
understand thoroughly the impacts of
this disposal technique.
Many plants have used wastes of
relatively low toxicity to supplement
their fuel needs. In addition, re-
searchers in Canada, Sweden, and the
United States have successfully dem-
onstrated extremely high destruction
efficiencies in cement kilns when
burning highly toxic organic wastes.
These studies indicate that a significant
potential exists for the expanded use
of cement kilns to safely dispose of
many types of hazardous wastes
generated in the United States and
Puerto Rico.
The risks incurred in burning toxic
wastes in cement kilns appear to be
very low. Given proper controls,
emissions of organic compounds are
likely to be at or below analytical limits
of detection. Particulate loadings will
increase when halogenated wastes
are burned; hence, excess dust capture
capacity may be required to utilize this
type of waste effectively.
The economics of using waste fuels
appears to be quite favorable for both
cement plants and waste suppliers.
Disposing of hazardous wastes through
incineration or landfilling is likely to
be more costly to waste generators
than utilizing cement kilns. Cement
plants using waste fuels could poten-
tially reduce production costs by up to
several dollars per ton.
This Project Summary was devel-
oped by EPA's Industrial Environ-
mental Research Laboratory, Cincin-
nati, OH, 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).
Background
The development of sound methods
for disposing of hazardous industrial
wastes is critical to ensuring the
protection of public health and the
environment. Although some restric-
tions and uncertainties exist as to the
types and quantities of wastes that can
be used as fuels in cement plants,
cement kiln disposal is likely to be both
environmentally and economically
superior to conventional disposal meth-
ods such as landfilling and incineration.
A large volume of organic industrial
wastes currently being generated in the
United States and Puerto Rico could
potentially be used as supplemental
fuels in commercial cement kilns. Prior
research has successfully demonstra-
ted the safe destruction of several waste
materials in cement kilns, including
chlorinated hydrocarbons and highly
toxic and stable wastes such as PCBs.
Based on these studies, it appears that
the wet-process cement plants located in
the U.S. have the potential capacity to
dispose of all chlorinated organic liquid
wastes generated in this country.
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Fuel costs, which can represent up to
65 percent of the direct cost of product ng
cement clinker, could be substantially
reduced through the use of waste fuels.
Because of the positive value assigned
to wastes used as fuels, the costs to
waste generators disposing of wastes
in cement kilns are expected to be rela-
tively low. Regulations enacted under
Subtitle C of the Resource Conservation
and Recovery Act provide additional in-
centives for waste disposal in cement
kilns. Under these regulations, wastes
sent directly to a cement plant from the
waste generator are exempt from most
of the standards applicable to hazardous
wastes.
This study has focused on the status
of waste fuel use in the cement
industry. The technical and environ-
mental aspects of waste fuel use,
including a review of previous research
and a discussion of the appropriate
control technology are presented in this
report.
Conclusions
The high cost incurred in disposing of
hazardous wastes in an environmentally
sound manner has led many industries
to reduce waste generation rates
through process changes and increased
recycling. However, significant quanti-
ties of industrial wastes will continue to
be generated which require disposal. At
present, landfilling and incineration are
the only disposal technologies employed
on a significant scale in the United
States. Cement manufacturing kilns
could potentially be employed to dispose
of large amounts of organic industrial
wastes that would otherwise be incin-
erated or landfilled. Cement kiln disposal
is not only more economical than other
disposal techniques, but, when properly
controlled, appears to be environmen-
tally superior to conventional disposal.
Because many waste products can be
readily used as fuels or processed into
supplemental fuels, a waste fuel market
is rapidly developing in the U.S. Waste
generators typically contract with a
disposal firm to remove their unwanted
byproducts and wastes. The disposal
firm will, if possible, distill the organic
wastes, reclaim any valuable compon-
ents for use as feedstocks, sell that
portion of the waste stream that can be
used as a fuel, and dispose of residues
through landfilling or incineration.
Some materials, such as used lubricating
oils, may simply be accumulated into
large batches and sold directly as fuels.
If the waste fuel does not contain
significant quantities of toxic metals,
halogenated materials, or toxic organics,
it can usually be safely and economically
substituted for coal, oil or natural gas in
most industrial processes. However, the
hazardous nature of combustion pro-
ducts from halogenated and highly toxic
wastes precludes their use as fuels in
most industrial processes, cement
manufacture being the notable exception.
Cement kilns provide a suitable
environment for the complete destruc-
tion and assimilation of even the most
stable and toxic wastes. The high
temperatures, long residence times and
strong turbulence encountered in
cement kilns have been shown todestroy
waste materials such as PCBs to beyond
analytical detection limits. In addition,
the highly caustic environment of
cement kilns acts as an effective
scrubbing system for removing acidic
residues, such as hydorchloric acid, that
can be formed during the combustion of
many wastes. The inability of other
industries to use halogenated and
highly toxic wastes as fuels combined
with the demonstrated destructive
capacity of cement kilns implies that a
tremendous potential exists for using
chlorinated wastes as supplemental
kiln fuels.
According to EPA estimates, approx-
imately 650,000 metric tons of chlori-
nated wastes are produced annually in
the U.S., primarily in Texas and Louisi-
ana. Wet-process cement kilns, the type
most likely to use chlorinated wastes,
are located throughout the U.S. including
the Southern states. Based on past
research, which indicated that chlorine
may be introduced into wet-process
cement kilns at rates of up to about 0.6
percent of the clinker production rate,
U.S. cement plants have the capacity to
dispose of all chlorinated wastes being
generated in this country. In addition,
large batches of wastes such as PCB-
contammated oils stored at sites around
the country could be disposed of in
cement kilns.
The economics of waste disposal in
cement kilns has not been clearly
demonstrated to date. However, because
the additional capital expenditures and
operating costs at a cement plant using
waste fuels on a routine basis are
anticipated to be relatively low, cement
kiln disposal is expected to be econom-
ically attractive to both the cement
industry and to waste generators. Older
wet-process cement plants, which
appear uniquely suited to using chlori-
nated waste fuels, are further attracted
to this technology because it would hel|
to regain some of the competitive edgi
now enjoyed by generally newer, mort
efficient, dry-process plants.
Despite the demonstrated safety o
using cement kilns to dispose of wasti
products, some uncertainties still exis
concerning the mechanisms of wasti
destruction within cement kilns. Unti
these mechanisms are better under
stood, the applicability of availabli
performance data to other kiln design;
and waste types will remain question
able.
The most significant barrier to tht
expanded use of waste fuels in cemen
kilns is the difficulty of obtaining the
necessary public support for sucf
programs. Public concern over potentia
health hazards has made state pollutior
control authorities reluctant to issue
even limited-duration trial-burn permits
for the use of any waste other thar
relatively innocuous materials. Tc
overcome those fears and successfully
foster the implementation of this
technology on a significant scale, it will
be necessary to expand the existing
information base to the point where kiln
performance can b.e reliably predicted
through a detailed understanding of the
mechanisms of waste destruction in
cement kilns. These goals could be
accomplished most effectively through
a research/demonstration program
conducted by the U.S. Environmental
Protection Agency.
Recommendations
The use of waste organic materials as
supplemental fuels in cement kilns
should be examined by the U.S. Envi-
ronmental Protection Agency in order to
determine if there is a need for regula-
tions covering this activity. Currently,
this activity is not covered by EPA
regulations.
The necessary research can be
accomplished most effectively through
Federal sponsorship of research/dem-
onstration projects at selected cement
plants. These projects should be struc-
tured to gather the information required
to fully understand the mechanisms
controlling waste destruction in cement
kilns and the variables affecting system
performance. The projected research
needs are discussed in detail in Section
7 of this report.
The pressing need to establish safe,
environmentally acceptable disposal
methods and sites will certainly be
alleviated if this technique proves to be
satisfactory.
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Douglas L Hazelwood and Francis J. Smith are with A. T. Kearney, Inc.,
Alexandria, VA 22313; Ellis M. Gartner is with Portland Cement Association,
Skokie. IL 60077.
Leo Weitzman and Harry Freeman are the EPA Project Officers (see below).
The complete report, entitled "Assessment of Waste Fuel Use in Cement Kilns,"
(Order No. PB 82-236 043; Cost: $ 10.50, subject to change) will be avaitable
only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officers can be contacted at:
Industrial Environmental Research Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
* US.GOVERNMENTPfllNTINO OFFICE 1982-559-017/0841
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United States
Environmental Protection
Agency
Center for Environmental Research
Information
Cincinnati OH 45268
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