vvEPA
Research and
Development
(MD-235)
EPA/540/A5-89/008
June 1989
American Combustion
Pyretron Destruction
System
Applications Analysis Report
SUPERFLWD INNOVATIVE
TECHNOLOGY EVALUATION
-------
1
-------
EPA/540/A5-89/008
June 1989
American Combustion Pyretron
Destruction System
Applications Analysis Report
Risk Reduction Engineering Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, OH 45268
-------
Notice
The information in this document has been funded by the U.S. Environmental
Protection Agency under Contract No. 68-03-3267 to Acurex Corporation. It has been
subjected to the Agency's peer review and administrative review and it has been
approved for publication as a USEPA document. Mention of trade names or
commercial products does not constitute an endorsement or recommendation for use.
u
-------
Foreword
The Superfund Innovative Technology Evaluation (SITE) program was authorized in
the 1986 Superfund amendments. The program is a joint effort between EPA's Office of
Research and Development and Office of Solid Waste and Emergency Response. The
purpose of the program is to assist the development of hazardous waste treatment
technologies necessary to implement new cleanup standards which require greater
reliance on permanent remedies. This is accomplished through technology
demonstrations which are designed to provide engineering and cost data on selected
technologies.
This project consists of an analysis of American Combustion's Pyretron oxygen
enhanced burner system. The technology demonstration took place at U.S. EPA's
Combustion Research Facility in Jefferson, Arkansas, and used a mixture of decanter
tank tar sludge from coking operations (RCRA listed waste K087) and soil excavated
from the Stringfellow Superfund site in Riverside, California. The demonstration
effort was directed at obtaining information on the performance and cost of the process
for use in assessments at other sites. Documentation will consist of two reports. The
Technology Evaluation Report (EPA/540/5-89/005)" describes the field activities and
laboratory results. This Applications Analysis provides an interpretation of available
data and discusses the potential applicability of the technology.
Additional copies of this report may be obtained at no charge from EPA's Center for
Environmental Research Information, 26 West Martin Luther King Drive, Cincinnati,
Ohio, 45268, using the EPA document number found on the report's front cover. Once
this supply is exhausted, copies can be purchased from the National Technical
Information Service, Ravensworth Bldg., Springfield, VA, 22161, (702) 487-4600.
Reference copies will be available at EPA libraries in their Hazardous Waste
Collection. You can also call the SITE Clearinghouse hotline at 1-800-424-9346 or 382-
3000 in Washington, D.C. to inquire about the availability of other reports.
Margaret M. Kelly, Director
Technology Staff, Office of
Program Management and
Technology
Alfre^i W. Lindsey, Acting Director
Office of Environmental Engineering
and Technology Demonstration
111
-------
Abstract
Incineration is widely used to clean up Superfund sites. Modifications which improve
the efficiency with which waste can be incinerated are therefore of interest to EPA.
Oxygen/air burners are of interest because their installation on conventional
incinerators can allow for significant increases in waste feedrate and on-line time. It is
for this reason that an oxygen/air burner was evaluated in the SITE program.
The Pyretron Thermal Destruction System is an innovative oxygen enhanced burner
system which can be used in conjunction with a conventional incinerator to treat
Superfund site wastes amenable to treatment via incineration. The major advantage
to the Superfund program of using the Pyretron, or other oxygen/air burners, is that
the waste feedrate of low BTU content solids and, under some circumstances, high
BTU content solids can be significantly increased. The throughput rate was doubled in
a test incinerator using the Pyretron to treat waste with a heating value of 24.1 MJ/kg
(10,400 BTU/lb) during the demonstration. This was achieved only with the injection
of water into the kiln to provide additional heat absorption capacity. While water
injection was successful in this case, it may not be practical for wastes with heating
values significantly above that used during the SITE demonstration. Its usefullness in
treating low heating value wastes may make the Pyretron applicable to many wastes
found at Superfund sites.
The Pyretron system may offer economic advantages over conventional incineration in
treating low heating value wastes in situations where auxiliary fuel and operating
labor costs are relatively high and delivered oxygen costs are relatively low. This is
because, in these situations, throughput increases would offset the added costs of
oxygen and capital equipment associated with the use of this technology. Economic
advantages do not exist in reverse situations (relatively low fuel and operating labor
costs/relatively high delivered oxygen costs). The economic advantage results from
fuel savings and increased waste throughput capabilities, offset by process equipment
and oxygen costs. Since the Pyretron is a burner system and therefore only part of an
incineration system, regulatory requirements, environmental monitoring
requirements, material handling requirements, and personnel issues applicable to a
Pyretron system application are not measurably different than those applicable to the
use of a conventional burner mounted on a transportable incinerator.
IV
-------
Contents
Page
Foreword iii
Abstract iv
Tables vii
Figures viii
Acknowledgments ix
1. Executive Summary 1
2. Introduction 3
2.1 The SITE Program 3
2.2 SITE Program Reports 3
2.3 Key Contacts 4
3. Technology Applications Analysis 5
3.1 Introduction 5
3.2 Conclusions 5
3.3 Site Characteristics Suitable for Pyretron System Implementation .... 6
3.3.1 Size of Operation 6
3.3.2 Pathways for Offsite Migration 6
3.3.3 Physical Site Characteristics 7
3.4 Regulatory Requirements 7
3.4.1 Federal EPA Regulations 7
3.4.2 State and Local Regulations 8
3.5 Monitoring Requirements 9
3.6 Applicable Wastes 10
3.7 Personnel Issues 10
3.7.1 Operator Training 10
3.7.2 Health and Safety 10
3.7.3 Emergency Response 10
3.8 Summary 10
4. Economic Analysis 13
4.1 Methodology 13
4.2 Assumptions 13
4.3 Cost Evaluation 14
4.3.1 Capital Costs and Benefits 14
4.3.2 Operating Costs and Benefits 16
4.3.3 Benefit Summary 17
References 18
-------
Contents (Continued)
Appendix A - Process Description 19
A.I Treatment Process 19
A.2 Innovative Features 19
Appendix B - Vendor Claims 21
B.I Incinerator Operational Benefits 21
B.2 Process Economic Evaluation 22
B.2.1 Method and Assumptions 22
B.2.2 Cost Evaluation 27
Appendix C - Site Demonstration Results 31
C.I Demonstration Test Program 31
C.2 Demonstration Test Results . 32
C.3 Demonstration Test Conclusions 38
Appendix D - Case Studies 41
D.I Introduction 41
D.2 Pyretron Studies at AEERL 41
D.3 Integration of These Results with Those of the SITE Demonstration .. 42
D.4 The Use of an Oxygen Burner at Denney Farm 43
D.5 Integration of These Results with Those of the SITE Program 44
References for Appendices 45
VI
-------
Tables
Number PaSe
1 Daily Labor Rate Calculation 15
2 Cost Evaluation Assumptions 15
3 Summary of Incremental Savings (< Costs >) for the
Pyretron System 18
B-l Optimum Operating Parameters Determined in the
Demonstration Test Program 23
B-2 Unit Conversion (Si-English) Used in this Analysis 23
B-3 Crew Costs - Daily Loaded Rate (24-Hour Operation) 25
B-4 Cost Evaluation Assumptions 28
B-5 Summary of Incremental Savings and (Costs) for the
Pyretron System 28
C-l POHC Concentration Estimates 31
C-2 Average Incinerator Operating Conditions for the
Tests Performed 33
C-3 Scrubber Discharge POHC DREs 39
C-4 NOX Levels Observed During the SITE Demonstration 39
vn
-------
Figures
Number Page
A-l Pyretron Thermal Destruction System process diagram 20
C-l CRF rotary kiln system 32
C-2 Kiln data for the conventional incineration scoping test:
65.6 kg/hr (10.9 kg every 10 min) 34
C-3 Stack emission monitor data for the conventional incineration
scopingtest: 65.6 kg/hr (10.9 every 10 min) 35
C-4 Kiln data for the optimum conventional incineration test:
47.7 kg/hr (9.5 kg every 12 min) 36
C-5 Kiln data for the Pyretron system test at increased charge mass:
47.7 kg/hr (15.5 kg every 19.5 min) 37
C-6 Kiln data for the optimum Pyretron system test: 95.5 kg/hr
(9.5 kg every 6 min) 38
D-l Block diagram of MIS system 43
vni
-------
Acknowledgments
This report was prepared under the direction and coordination of Laurel J. Staley,
EPA SITE Program Manager in the Risk Reduction Engineering Laboratory --
Cincinnati, Ohio. Contributors and reviewers for this report were Gordon Evans,
Steven James, Robert Olexsey, Robert Stenburg, Gregory Carroll, John Kingscott,
Richard Valentinetti, and Ronald Hill of the USEPA and Mark Zwecker of American
Combustion.
This report was prepared for EPA's Superfund Innovative Technology Evaluation
(SITE) Program by L. R. Waterland, C. I. Okoh, and A. S. McElligott of Acurex
Corporation, under EPA Contract 68-03-3267
IX
-------
-------
Section 1
Executive Summary
The Pyretron Thermal Destruction System is an
innovative burner system employing dynamic
oxygen enhancement of the combustion process. The
system is designed to be used in conjunction with a
conventional transportable or fixed rotary kiln
incinerator and is intended to increase the efficiency
of conventional incineration.
Relatively little data exist for evaluation of the
technology besides information from the SITE
demonstration which was conducted at the EPA's
Combustion Research Facility. An additional study
was conducted by the EPA's Air and Energy
Engineering Research Laboratory (AEERL). The
results of this study are summarized in Appendix D
of this report. The conclusions of this Applications
Analysis are:
1. The Pyretron burner system is a viable
technology for treating Superfund waste.
2. The system is capable of doubling the capacity of
a conventional rotary kiln incinerator. The
greatest capacity increases will occur for wastes
with low heating value.
3. Increased capacity can result in cost savings.
This will be primarily affected by labor cost,
length of the cleanup, and the local costs of
oxygen and fuel.
4. In situations in which particulate carryover
resulting from excessive gas volume causes
operational problems, the Pyretron may increase
reliability. This is because, by replacing some of
the combustion air with oxygen, using the
Pyretron reduces combustion gas volume.
5. Data from the SITE demonstration do not show a
statistically significant difference in the level or
frequency of transient emissions. An average of
16 transients/test were observed during air-only
operation. Only 6 transients/test were observed
during oxygen-enriched operation.
The Pyretron system can be used to treat any waste
amenable to treatment via conventional
incineration. However, its primary advantage,
increased throughput, can best be realized in the
treatment of solid wastes with relatively low heating
value. This is because the major factor limiting
throughput for low heating value wastes is the
volume of combustion gas required for incineration of
a unit volume of waste. Since oxygen enhancement
reduces combustion volume by displacing diluent
nitrogen in the combustion air stream,- it
significantly reduces the volume of combustion gas
required, thus allowing throughput increases for this
type of waste. For this reason, it may prove useful in
the treatment of Superfund site wastes.
American Combustion, Inc. (ACI) states that
Pyretron system offers three advantages over
conventional incineration. These are:
The Pyretron system will be capable of
reducing the magnitude of transient high
levels of carbon monoxide (CO), unburned
hydrocarbon, and soot ("puffs") that can occur
with repeated batch charging of a high heat
content waste to a rotary kiln.
The Pyretron system will allow increased
waste feedrate to the kiln while still
achieving the hazardous waste incinerator
performance standards for POHC destruction
and removal efficiency (DRE) and particulate
emissions.
The Pyretron system is more economical than
conventional incineration.
These claims were evaluated during the SITE
demonstration of the Pyretron at the EPA
Combustion Research Facility (CRF) which occurred
from November 1987 to January 1988. The
demonstration tests were conducted using waste
material excavated from the Stringfellow Superfund
site near Riverside, California. The Stringfellow soil
was combined with a high heating value listed
hazardous waste, KO87, which is decanter tank tar
sludge from coking operations. The objective of the
demonstration tests was to provide the data to
evaluate the three ACI claims regarding the
Pyretron system noted above.
-------
The Pyretron system designed for use in the SITE
demonstration consists of two burners, one installed
in the primary combustion chamber (kiln) and one
installed in the afterburner; valve trains for
supplying these burners with controllable flows of
auxiliary fuel, oxygen, and air; a computerized
process control system; an oxygen supply system; and
a kiln water injection system. The Pyretron burners
use a proprietary parallel combustion approach based
upon the independent introduction of either air,
oxygen-enriched air or pure oxygen.
With respect to the first ACI claim, the
demonstration test results were inconclusive. This
claim was to be evaluated through a time series
comparison of the transients observed during oxygen-
enhanced and air-only operation. Insufficient
numbers of transients were generated to complete
this analysis. During the course of each 8-hour test
conducted during the SITE demonstration, an averae
of 16 transients/test occurred during air only
operation. A total of 6 transients/test occurred during
oxygen enriched operation. These data are described
in more detail in the Technology Evaluation Report
on the Pyretron.This may have been caused, in part,
by the non-uniform nature of the waste feed used.
Non-uniformity of this type is typical of Superfund
waste streams and may make it difficult to evaluate
transient performance in the field. The effect of the
Pyretron on transient emissions was studied by the
USEPA's Air and Energy Engineering Research
Laboratory (AEERL) using simulated waste batch
fed to a rotary kiln simulator. The results of that
study, summarized in Appendix D, indicate that
oxygen enhancement may worsen transient
emissions.
With respect to the second ACI claim, demonstration
test results clearly indicated that 99.99 percent
POHC DRE was achieved with the Pyretron system
at double the waste feedrate possible under
conventional operation. Water injection was
required, however, to accomplish the throughput
increases. This is because the nitrogen that is
displaced when oxygen is added to the combustion air
stream is needed as a heat sink when high heating
value wastes are incinerated. Without that nitrogen,
a substitute heat sink must be used. Water injection
adequately served that purpose during the
demonstration. However, this may not be practical
inall situations. In addition, particulate emissions of
significantly less than 180 mg/dscm at 7 percent 02
were measured. Finally, the solid and liquid residues
generated during the SITE demonstration were
contaminant free.
With respect to the third ACI claim, cost estimates
show that use of the Pyretron system in treating a
waste with characteristics similar to the waste
material used during the demonstration tests can be
less costly than conventional incineration in
situations where auxiliary fuel and operating labor
costs are relatively high, and oxygen costs are
relatively low. The analysis indicates a potential for
substantial savings under favorable circumstances.
for the evaluation case assumed, treatment of 4,480
tonnes (4,930 tons) of waste with characteristics
similar to the material incinerated during the
demonstration test program, Pyretron system
treatment costs were $31/tonne ($28/ton) less than
conventional incineration treatment costs. The
wastes employed in the demonstration tests had
relatively high heating value (24.1 MJ/kg (10,400
Btu/lb)).
-------
Section 2
Introduction
2.1The SITE Program
In 1986, the EPA's Office of Solid Waste and
Emergency Response (OSWER) and Office of
Research and Development (ORD) established the
Superfund Innovative Technology Evaluation (SITE)
Program to promote the development and use of
innovative technologies to clean up Superfund sites
across the country. Now in its third year, SITE is
helping to provide the treatment technologies
necessary to implement new federal and state
cleanup standards aimed at permanent remedies,
rather than quick fixes. The SITE Program is
composed of three major elements: the
Demonstration Program, the Emerging Technologies
Program, and the Measurement and Monitoring
Technologies Program.
The major focus has been on the Demonstration
Program, which is designed to provide engineering
and cost data on selected technologies. To date, the
demonstration projects have not involved funding for
technology developers. EPA and developers
participating in the program share the cost of the
demonstration. Developers are responsible for
demonstrating their innovative systems at chosen
sites, usually Superfund sites. EPA is responsible for
sampling, analyzing, and evaluating all test results.
The result is an assessment of the technology's
performance, reliability, and cost. This information
will be used in conjunction with other data to select
the most appropriate technologies for the cleanup of
Superfund sites.
Developers of innovative technologies apply to the
Demonstration Program by responding to EPA's
annual solicitation. EPA also will accept proposals at
any time when a developer has a treatment project
scheduled with Superfund waste. To qualify for the
program, a new technology must be at the pilot or full
scale and offer some advantage over existing
technologies. Mobile technologies are of particular
interest to EPA.
Once EPA has accepted a proposal, EPA and the
developer work with the EPA Regional Offices and
state agencies to identify a site containing wastes
suitable for testing the capabilities of the technology.
EPA prepares a detailed sampling and analysis plan
designed to thoroughly evaluate the technology and
to ensure that the resulting data are reliable. The
duration of a demonstration varies from a few days to
several months, depending on the length of time and
quantity of waste needed to assess the technology.
After the completion of a technology demonstration,
EPA prepares two reports, which are explained in
more detail below. Ultimately, the Demonstration
Program leads to an analysis of the technology's
overall applicability to Superfund problems.
The second principal element of the SITE Program is
the Emerging Technologies Program, which fosters
the further investigation and development of
treatment technologies that are still at the laboratory
scale. Successful validation of these technologies
could lead to the development of a system ready for
field demonstration. The third component of the SITE
Program, the Measurement and Monitoring
Technologies program, provides assistance in the
development and demonstration of innovative
technologies to better characterize Superfund sites.
2.2 SITE Program Reports
The analysis of technologies participating in the
Demonstration Program is contained in two
documents, the Technology Evaluation Report and
the Applications Analysis Report. The Technology
Evaluation Report contains a comprehensive
description of the demonstration sponsored by the
SITE program and its results. This report gives a
detailed description of the technology, the site and
waste used for the demonstration, sampling and
analysis during the test, and the data generated.
The purpose of the Applications Analysis Report is to
estimate the Superfund applications and costs of a
technology based on all available data. This report
compiles and summarizes the results of the SITE
demonstration, the vendor's design and test data, and
other laboratory and field applications of the
technology. It discusses the advantages,
disadvantages, and limitations of the technology.
Costs of the technology for different applications are
estimated based on available data on pilot- and full-
scale applications. The report discusses the factors,
-------
such as site and waste characteristics, that have a
major impact on costs and performance.
The amount of available data for the evaluation of an
innovative technology varies widely. Data may be
limited to laboratory tests on synthetic wastes, or
may include performance data on actual wastes
treated at the pilot or full scale. In addition, there are
limits to conclusions regarding Superfund
applications that can be drawn from a single field
demonstration. A successful field demonstration does
not necessarily assure that a technology will be
widely applicable or fully developed to the
commercial scale. The Applications Analysis
attempts to synthesize whatever information is
available and draw reasonable conclusions. This
document will be very useful to those considering the
technology for Superfund cleanups and represents a
critical step in the development and
commercialization of the treatment technology.
2.3 Key Contacts
For more information on the demonstration of the
Pyretron technology, please contact:
1. EPA project manager concerning the SITE
demonstration:
Ms. Laurel Staley
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
26 W. Martin Luther King Jr. Drive
Cincinnati, Ohio 45268
(513) 569-7863
2. Vendor concerning the process
Mr. Mark Zwecker
American Combustion, Incorporated
2985 Gateway Drive
Norcross, Georgia 30071
(404) 662-8156
3. EPA project manager concerning the Combustion
Research Facility
Mr. Robert Thurnau
U.S. Environmental Protection Agency
Risk Reduction Engineering Laboratory
26 W. Martin Luther King Jr. Drive
Cincinnati, Ohio 45268
(513) 569-7429
There are other vendors of oxygen/air burner
systems. One such system was used in the EPA
sponsored cleanup of dioxin contaminated soil in
Southwest Missouri. Information on the performance
of this burner is presented in Appendix D.
-------
Section 3
Technology Applications Analysis
Incineration is currently a significant Superfund
SITE remediation option. For example,
incineration/thermal destruction was selected as the
source control remediation for 26 of 76 (or roughly
one third) of the Records of Decision signed in
1988.(1) For remediations using on-site incineration,
the decontamination of soils and sludges is of
predominant interest. While many feed-related
factors affect incinerator feed rates and reliability,
the particle size distribution, heat content, and
moisture content of the soils and sludges have
distinct effects. Oxygen enhance ment or pure oxygen
burners used on on-site incinerators are of interest to
the Superfund program in that they offer the
potential to increase both feed rates and equipment
reliability, thus lowering costs, for solid feeds having
a wide variety of particle sizes, heat values, and
moisture contents.
The Pyretron system is an air/oxygen burner that can
be used with any incinerator considered for
Superfund site waste treatment provided certain
implementation criteria are satisfied. This section
discusses the general applicability of the technology
and describes possible constraints to its application.
3.1 Introduction
This section of the report addresses the applicability
of the process to varying potential feedstocks based
upon the results obtained from the SITE
Demonstration Test and the study of the Pyretron
system at the EPA's Air and Energy Engineering
Research Laboratory (AEERL) in Research Triangle
Park, North Carolina.(2) In addition, some
information is available from an oxygen burner on
EPA's Mobile Incineration System at the Denney
Farm site in Missouri. Neither study was done under
the SITE program and neither will be discussed in
detail. They will only be used to support conclusions
drawn during the demonstration. Both studies are
summarized in Appendix D.
Following are the overall conclusions being drawn
about the Pyretron based upon the results of the SITE
demonstration. Appendix C provides a summary and
discussion of the results of the SITE demonstration.
These results are explained in more detail in the
Technology Evaluation Report. (3)
3.2 Conclusions
The conclusions drawn from reviewing the data on
the Pyretron system are as follows.
1.Using the Pyretron system with oxygen
enhancement can enable significant waste
throughput increases to be achieved. Incinerator heat
release capacity limits these throughput increases for
wastes with very high heating value. For wastes with
moderately high heating value, water injection can
provide sufficient heat absorption capacity to enable
significant throughput increases to be achieved. For
wastes with low heating value, throughput increases
should be readily achieved since they would not be
limited by the heat release capacity of the
incinerator. These results are supported by
experience at another hazardous waste incinerator
that made use of oxygen enhancement. Experience
with this device is summarized in Appendix D.
2.Because of the abovementioned throughput
increases, the Pyretron system can make hazardous
waste incineration more economical in situations in
which the throughput increases are large, the
operating and fuel costs are high and oxygen costs are
relatively low. Since the Pyretron is a burner system
and therefore only a part of an incineration system
the capital costs associated with the Pyretron system
are expected to be small relative to the costs of the
entire incinerator. Operating and utility costs per ton
of waste processed are expected to be reduced most by
use of the Pyretron in situations in which throughput
increases are readily achievable.
This result is supported by experience at another
hazardous waste incinerator that has employed
oxygen enhancement (see Appendix D).
3.The results of the SITE demonstration do not show
that the Pyretron system can reduce transient
emissions. Data obtained from the demonstration do
not show a statistically significant difference
between the frequency and level of transient
emissions observed with air-only and oxygen
-------
enhanced operation. During air-only operation, an
average of 16 spikes/test were observed. Only 6
spikes/test were observed for oxygen-enhanced
operation. During the SITE demonstration, transient
emissions, contrary to expectation, were not an
operational problem which significantly hindered
operation of the incinerator. Waste throughput was
limited much more by the heat release capacity of the
incinerator at the CRF than by the onset of transient
emissions. The heat release limitations were
overcome by water injection.
4.Levels of NOX observed during the SITE
demonstration were roughly an order of magnitude
higher when oxygen enhancement was used (see
Appendix C, Table C-4). These results are consistent
with those obtained from the study at AEERL on a
smaller version of the Pyretron. Those studies also
found very high Levels of NOX and indicated that
high flame temperature is the predominant factor in
producing high levels of NOX emissions (see
Appendix D). Further design and development of the
Pyretron focusing on reducing the flame
temperature, may alleviate this problem. See
Appendix C, of the Technology Evaluation Report (3)
for further details.
3.3 Site Characteristics Suitable for
Pyretron System Implementation
3.3.1 Size of Operation
The Pyretron is a burner system incorporating
oxygen enhancement of the combustion process. It is
available in several size ranges from 0.29 to 73 MW
(1 to 250 MMBtu/hr) heat input. Thus, it can be
retrofitted to a wide variety of incinerator sizes.
The physical size of an incineration treatment
process using the Pyretron system would be
essentially the same as an incinerator with
conventional burners. Thus, most of the candidate
transportable incinerators for using the Pyretron
systems are expected to be in the 9 to 15 MW (30 to 50
MMBtu/hr range), although some new systems are
being built with capacities up to 23 MW (80
MMBtu/hr). Process equipment and other site
requirements such as laboratory support, sample
transportation, materials storage for processing,
chemical analysis, decontamination, waste storage
and removal, and other auxiliary process and
equipment requirements would be the same for the
Pyretron system as for conventional incineration.
The only addition to physical treatment size required
by Pyretron system would be an oxygen supply
system and a water supply system. Trailer-mounted
liquid oxygen tanks with evaporators are available
and could be used instead of a fixed oxygen supply
tank. The water supply system to allow rotary kiln
temperature control would not add significantly to
the size of the complete incinerator system.
Waste treatment rates for transportable incinerators
are generally in the 0.9 to 9.1 tonnes/hr (1 to 10
ton/hr) range. For a typical contaminated soil or
sludge with specific gravity of about 2, this would
translate to a treatment capacity of between 3,060
and 30,600 m3/yr (4,000 and 40,000 yd3/yr). For
illustration, 4,050 m2 (1 acre) excavated to a depth of
0.91 m (3 ft) would contain 11,100 m3 (14,500 yd3).
Thus, one or more years would be required to treat
expected Superfund site waste volumes.
For wastes with relatively low heating value (e.g.
common soil with 20% moisture and less than one
percent organic contamination), significantly
increased waste throughput capability could be
realized with the Pyretron system for the following
reason. Throughput limitations for low heating value
wastes are based on combustion gas volume
limitations. Combustion gas is primarily comprised
of nitrogen from the air (4 parts nitrogen to 1 part
oxygen) and water vapor from soil moisture and from
the combustion reactions that take place. If the
combustion gas .volume is too,high, excessive gas
velocities result. These velocities lead to operational
problems such as particle entrainment (in the case of
soils) and loss of gas residence time. When oxygen is
added to the combustion air stream and displaces
nitrogen, this reduces the combustion gas volume
alleviating the above operational problems and
making it possible to operate at higher feedrates and
with less downtime.
For wastes with higher heating values, increased
throughput with the Pyretron is still possible,
although not as readily achieved as with lower
heating value wastes. This is because, if the organic
content and resulting heating value of the feed is too
high, throughput will be limited by the heat release
limitations of the incinerator. Control of the kiln
temperature can become difficult at elevated feed
rates and, as a result, feed capacity can be restricted.
Water injection can increase kiln capacity under
these conditions because water provides a very
effective heat sink. However, the resulting water
vapor increases the combustion gas volume and
decreases the secondary combustion chamber
residence time, thus limiting the effectiveness of
water injection as a means of achieving a throughput
increases.
3.3.2 Pathways for Off-site Migration
The pathways for offsite migration of wastes are the
same for Pyretron incineration as for conventional
incineration. Wastes include effluent from the air
pollution control system employed (blowdown from a
wet scrubber or particulate and/or spent dry sorbent
-------
from a dry scrubber system). Offsite migration of
stack emissions can also occur. The Pyretron system
has a potential for emitting higher NOX levels than
conventional burners, although it may be possible to
address this problem by designing the system for low-
NOX operation.
3.3.3 Physical Site Characteristics
The requirements on general site characteristics
such as topography, geotechnical features, site
access, hydrology, and climate requirements for a
Pyretron application are the same as for conventional
incineration.
The utility requirements include such conventional
incineration needs as electricity and water. In
addition, the Pyretron thermal destruction system
requires an oxygen supply system. Trailer-mounted
liquid oxygen tanks with evaporators are available.
In addition, safety codes affect the installation and
handling of oxygen.
The site security requirements are the same as for
conventional incineration with added concern for the
liquid oxygen tank. Flammables and fire sources
must be kept at a reasonable distance to prevent
increased risk of fire or explosion.
3.4 Regulatory Requirements
Section 121 of CERCLA requires that, subject to
specified exceptions, remedial actions must be
undertaken in compliance with applicable or
relevant and appropriate requirements (ARARs),
Federal laws, and more stringent promulgated State
laws (in response to releases or threats of releases of
hazardous substances or pollutants or contaminants)
as may be necessary to protect human health and the
environment.
The ARARs which must be followed in incinerating
Superfund waste onsite are outlined in the Interim
Guidance on Compliance with ARAR, Federal
Register, Vol. 52, pp. 32496 et seq. These are:
Performance-, Design-, or Action-Specific Re-
quirements. Examples include RCRA incin-
eration standards and Clean Water Act
pretreatment standards for discharges to
POTWs. These requirements are triggered by the
particular remedial activity selected to clean a
site.
Ambient/Chemical-Specific Requirements. These
set health-risk-based concentration limits based
on pollutants/contaminants, e.g., emissions
limits and ambient air quality standards
(NAAQS). The most stringent ARAR must be
complied with.
Locational Requirements. These set restrictions
on activities because of site location and
environs, e.g., Federal/State siting laws.
Superfund regulations in 40 CFR 300.68(a)(3) state
that Federal, State, and local permits are not
required for fund-financed remedial actions or
remedial actions taken pursuant to Federal action
under Section 106 of CERCLA. However, several
states such as Connecticut, Maine, Massachusetts,
New Hampshire, Rhode Island, Vermont, New
Jersey, New York, Pennsylvania, and California
have independent state Superfund laws that may be
more stringent than the Federal laws, and thereby
have primacy. In addition, some state and local
authorities such as the California South Coast Air
Quality Management District (SCAQMD) and
Department of Health Services (DHS) insist that all
potential Superfund site incinerators must be
permitted like any other incinerator -- in apparent
disagreement with the Federal regulation cited
above. Deployment of Pyretron systems will therefore
be affected by three main levels of regulation:
Federal EPA incinerator, air, and water pollution
regulations
State incinerator, air, and water pollution rules
Local regulations, particularly Air Quality
Management District (AQMD) requirements
These regulations affect all incinerators --
conventional or with the Pyretron system and the
following discussion focuses on the particular aspects
that are important to the Pyretron system.
3.4.1 Federal EPA Regulations
3.4.1.1 ARARs
As discussed in the interim guidance document on
compliance with ARAR (52FR32496), a requirement
under other environmental laws may either be
"applicable" or "relevant and appropriate" to a
remedial action, but not both. A two-tier test may be
applied: first, to determine whether a given
requirement is applicable; then, if it is not applicable,
to determine whether it is nevertheless relevant and
appropriate.
"Applicable requirements" means those cleanup
standards, standards of control, and other
substantive environmental protection requirements,
criteria, or limitations promulgated under Federal or
State law that specifically address a hazardous
substance, pollutant, contaminant, remedial action,
location, or other circumstance at a Superfund site.
"Applicability" implies that the remedial action or
the circumstances at the site satisfy all of the
-------
jurisdictional prerequisites of a requirement. For
example, the hazardous waste incinerator
regulations would apply for incinerators operating at
Superfund sites containing listed or characteristic
hazardous wastes.
"Relevant and appropriate requirements" means
those cleanup standards, standards of control, and
other substantive environmental protection
requirements, criteria, or limitations promulgated
under Federal or State law that, while not
"applicable" to a hazardous substance, pollutant,
contaminant, remedial action, location, or other
circumstance at a Superfund site, address problems
or situations sufficiently similar to those encountered
at the Superfund site that their use is well suited to
the particular site. For example, if a Superfund site
contained no specifically listed or characteristic
hazardous wastes, the hazardous waste incinerator
regulations might still be considered relevant and
appropriate.
3.4.1.2 Incinerator Regulations
The federal hazardous waste incinerator regulations
would be considered either "applicable" or "relevant
and appropriate" to the incineration treatment of a
Superfund site waste via either conventional
incineration or use of the Pyretron system. These
regulations establish hazardous waste incineration
performance standards as detailed in 40 CFR 264
subpart O. These rules are being revised, and the new
proposed regulations are due to be published in 1989.
These regulations are applicable to incineration of
hazardous wastes at a Superfund site, and may be
deemed relevant and appropriate to the incineration
of some wastes that are not specifically listed in 40
CRF Part 261.
The important incinerator regulations for both
conventional incineration as well as Pyretron system
deployment are:
Performance standards: Section 264.343
Operating requirements: Section 264.345
Monitoring and inspections: Section 264.347
Under the current version of these regulations, an
incinerator (with or without the Pyretron system)
will be required to:
Achieve a DRE of 99.99 percent for each principal
organic hazardous constituent (POHC) in the
waste feed
Control HC1 emissions to the larger of 1.8 kg/hr
(4 Ib/hr) or 1 percent of the stack HC1 prior to
entering any pollution control equipment
ğ Limit particulate emissions to less than 180
mg/dscm (0.08 grains/dscf), corrected to 7 percent
O2
Continuously monitor combustion temperature,
waste feedrate and an indicator of combustion
gas velocity
Continuously monitor CO in the stack exhaust
gas
As discussed in Appendix C, the Pyretron system
demonstration program established compliance with
these requirements.
3.4.1.3 Water Regulations
Provisions of the Safe Drinking Water Act also apply
to remediation of Superfund sites. CERCLA Section
121(d)(2)(A) and (B) explicitly mention three kinds of
surface water or groundwater standards with which
compliance is potentially required -- maximum
contaminant level goals (MCLGs), Federal water
quality criteria (FWQC), and alternate concentration
limits (ACLs) where human exposure is to be limited.
This section describes these requirements and how
they may be applied to Superfund remedial actions.
The guidance is based on Federal requirements and
policies; more stringent, promulgated state
requirements (such as a stricter classification scheme
for groundwater) may result in application of even
stricter standards than those specified in Federal
regulations.
3.4.2 State and Local Regulations
In addition to the Federal regulations noted in
Section 3.4.1, the Federal Prevention of Significant
Deterioration (PSD) and New Source Review (NSR)
regulations promulgated under the Clean Air Act
and administered by the states will impact Pyretron
system deployment through the emissions
monitoring control and process requirements or
through the permitting process in areas that require
permits to install and operate. In addition to these,
there are several local regulations that govern
incinerator operations because incinerators are
combustion devices (emissions sources) and each
incineration application is site-specific. Many of
these state and local emissions regulations are more
stringent than EPA rules and the cognizant
regulatory agencies have primacy. Pressure could,
therefore, be anticipated from state and local
authorities in relation to NOxiemissions, for example.
(The higher flame temperatures possible with the
Pyretron technology could increase the formation and
emission of NOX from air nitrogen and nitrogenous
wastes. This could contribute to the regulatory
pressure for NOX control.)
-------
There are six basic sources of potential regulations on
Pyretron system deployment at the state and local
level:
Permits to construct/operate
- Best available control technology (BACT)
triggers for stationary sources or units
- Cumulative or offset triggers
New Source Review
- BACT trigger levels and BACT designations
- Offset triggers
Prevention of Significant Deterioration
-BACT controls
- Increment limitations
General prohibitions on emissions levels
Source-specific standards on emissions levels
(currently none, but the mechanism exists)
Nuisance rules
Discharge permits may also be required from the
regional water quality board. Discharge permits
would apply equally to Pyretron applications and
conventional incinerators.
The major regulatory requirements will include
permits to install and operate as well as NSR/PSD
reviews as appropriate. Many states such as
California, New Jersey, Pennsylvania, Ohio, New
York, Texas, and Virginia will require some form of
NOX control and/or monitoring for CO, unburned
hydrocarbon (UHC), and NOX. These regulations will
apply to all incinerators, including those fitted with
the Pyretron system. The required control will be a
BACT, reasonably available control technology
(RACT), or lowest achievable emission rate (LAER)
control, and will range from exemptions for short
burns of small amounts of nonhazardous wastes in
transportable incinerators to very stringent criteria
pollutant control. Offsets may also be required in
areas that are in nonattainment for NO2, such as The
South Coast AQMD (SCAQMD) in California, or
nonattainment for ozone, such as the New York
metropolitan area.
Most of the relevant regulations specify an emissions
rate or level that may not be exceeded or that will
trigger corrective or punitive measures. For example,
the PSD NOX triggers are 91 tonnes/yr (100 tons/yr)
for new sources and 36 tonnes/yr (40 tons/yr) for
retrofits. By contrast, the nuisance rules are catch-all
rules that seek to prevent injury or annoyance to any
considerable number of persons or to the public.
Although these nuisance rules do not appear
aggressive or overbearing, the regulatory power of
the public cannot be overstated. Public opposition can
be more effective in stalling an incineration project
than Federal, State, or local regulation. Indeed,
public opposition can stall a project already approved
and permitted by the authorities. The process for
granting permits to install and operate usually have
provisions for public input, especially for waste
treatment projects. Permitting can easily become the
most expensive and time-consuming part of
deploying any incineration treatment project,
including a Pyretron application.
3.5 Monitoring Requirements
Pyretron system applications will most likely be
required to monitor CO and NOX emissions. The NOX
requirements will likely come from State and local
AQMD regulatory pressure for NOX control and, in
some areas, for ozone reduction. Continuous
monitoring will likely be required. The CO
requirement will stem from the Federal and State
incinerator regulations calling for continuous
monitoring. State and local AQMD emissions limits
also exist for CO, but Pyretron system applications
are likely to be well below these.
Incineration treatment systems will also be required
to continuously monitor such variables as
combustion temperature, waste feedrate, and an
indicator of combustion gas velocity. Further, if the
waste contains sulfur, scrubbing and SO2 monitoring
may be required by the air regulations. Other
sampling, analysis, equipment monitoring, and
inspections may be required as outlined in 40 CFR
264 Section 347. Finally, incineration systems will be
required to observe blowdown discharge and ash
residue disposal requirements during operation and
at closure. Unless the operator can demonstrate
according to 40 CFR 261.3(d) that the residue
removed from the incinerator is not a hazardous
waste, he will have to manage it in accordance with
the applicable requirements of 40 CFR Sections 262
through 266. Even for nonhazardous discharge, local
water quality board regulations as well as Federal
and State regulations will likely be enforced either as
"applicable" or as "relevant and appropriate."
Further guidance on these regulations are available
in CERCLA Section 121(d)(2)(A) and (B) as well as 40
CFR Section 35.
Again, it is worth noting that these regulations apply
to all incineration systems in general, as well as to
Pyretron system applications. The Pyretron is only at
a disadvantage with respect to NOX emissions. With
further development of the system, this disadvantage
could be eliminated.
-------
3.6 Applicable Wastes
The Pyretron system can be used to treat any waste
amenable to treatment by conventional incineration.
This includes wastes where hazardous constituents
are organic and wastes with sufficient organic
content that significant volume reduction is possible
with incineration, as well as aqueous wastes.
Nitrogen containing wastes should not be treated
because of the potential to exacerbate NOX emissions.
As explained above, the main advantage of the
Pyretron, throughput increases, are obtained for low
heating value wastes and not for high heating value
wastes. This is because the throughput increases
possible with the Pyretron are based on a reduction in
combustion gas volume. Combustion gas volume
reductions allow throughput increases predom-
inantly with low heating value wastes. Higher
heating value waste throughput is limited by the
heat release capacity of the incinerator and the
capacity for water injection to control kiln
temperature.
Wastes with relatively low heating value are most
appropriate for treatment with the Pyretron even if
they contain contaminants that might be expected to
contribute to transient emissions. Despite the results
of studies at AEERL which suggest that elevated
flame temperatures may increase transient
formation in some wastes, the formation of transient
emissions did not result in significant operational
problems as compared with the heat release
limitations of the kiln.
At the start of the demonstration it was believed that
the onset of transient process upsets would limit
waste throughput rate. The results of the
demonstration indicate that this was not the case for
the waste studied here. The waste used during the
demonstration had a relatively high heating value of
24.1 MJ/kg (10,400 BTU/lb). It was believed that this
waste would readily cause transient emissions to
occur when fed at high rates to the kiln and so would
be an appropriate waste to use to test the ability of
the Pyretron to increase throughput rates of such
wastes. Not only did this waste not form transient
emissions readily, the throughput increases achieved
with the Pyretron seemed mostly the result of the 136
L/hr of water injected into the kiln to provide added
heat absorption capacity. While transient emissions
may limit incineration capacity when some wastes
are treated (see Appendix D), this is certainly not a
universally occurring phenomenon and the dominant
factor limiting the throughput of high heating value
wastes is the heat release capacity of the kiln.
Materials handling requirements for a Pyretron
system application are the same as would apply to a
conventional incinerator application. These would
include waste pretreatment, probably waste
containerization, and treatment residuals handling
and disposal.
3.7 Personnel Issues
3.7.1 Operator Training
Training required for an operator of the Pyretron
system in a waste incineration application includes
that required by all hazardous waste incinerator
operators plus training specific to the Pyretron
system.
The training required of .all hazardous waste
incinerator operators is detailed in 40 CFR 264
subpart B, Section 264.16 subpart C on preparedness
and prevention as well as subpart D on contingency
plans and emergency procedures that also present
issues central to personnel training.
Additional operator training specific to the Pyretron
system may be required because of the generally
more sophisticated process control system and the use
of liquid oxygen.
3.7.2 Health and Safety
The health and safety issues involved in using the
Pyretron system for waste incineration are generally
the same as those that apply to all hazardous waste
incineration processes as detailed in 40 CFR 264
subparts B through G.
3.7.3 Emergency Response
The emergency response training for using the
Pyretron system is the same general training
required for operating a treatment, storage and
disposal (TSD) unit engaging in incineration as
detailed in 40 CFR 264 subpart D. Training must
address such fire-related issues as extinguisher
operation, hoses, sprinklers, hydrants, smoke
detectors and alarm systems, self-contained
breathing apparatus use, hazardous material spill
control and decontamination equipment use,
evacuation, emergency response planning, and
coordination with outside emergency personnel (e.g.,
fire/ambulance).
3.8 Summary
The Pyretron Thermal Destruction System is an
innovative combustion system for application to
waste incinerators.
The Pyretron system can be used to treat any waste
amenable to treatment via conventional
incineration. However, it is best for the treatment of
wastes with low heating value. For this reason, it
10
-------
may be quite useful in the treatment of Superfund
site wastes.
The available performance data for the Pyretron
system were obtained during the SITE demonstration
test program performed at EPA's Combustion
Research Facility from November 1987 through
January 1988 and from a study at the EPA's AEERL
laboratory in Research Triangle Park, North
Carolina. That study is summarized in Appendix D.
While the Pyretron with oxygen enhancement was
able to successfully decontaminate wastes at twice
the throughput rate possible with air-only operation,
the high levels of NOX observed during the site
demonstration may limit its applicability in
situations in which stringent NOX control is required.
11
-------
-------
Section 4
Economic Analysis
This section discusses the estimated marginal cost
and savings of adding a Pyretron system to a
conventional incineration unit during a Superfund
site remediation. A primary goal of this analysis is to
provide the reader with an independent cost analysis
which will help evaluate the validity of the vendor's
claim that the addition of the Pyretron system can
provide the conventional incinerator operator with
significant cost savings.
It is important to remember that the Pyretron
Thermal Destruction System is not a stand-alone
technology. Employing the Pyretron is a matter of
retrofitting it to, or installing it on, a conventional
incinerator. Thus, this analysis will employ an
incremental cost approach that is different than
other economic evaluations conducted for the SITE
program. Taking this approach means that this
economic analysis will focus on estimating the
incremental costs and benefits which are likely to
arise from adding a Pyretron burner to an existing
incinerator. This analysis will not attempt to
estimate the total clean-up costs possible under
incineration, with or without the retrofit. Ultimately,
the end user must factor the incremental costs and
benefits of using this system into a total cost estimate
for incineration.
4.1 Methodology
This analysis will employ the same methodology as
used by the vendor. The reader will find the vendor's
assumptions and methodology detailed in Appendix
B. It is a fundamentally sound approach, and by
using the same methodology, it will be possible for
the reader to make cross comparisons between the
vendor and Agency estimates. The key feature of this
analysis is that where it is appropriate, alternate
assumptions have been substituted for those offered
by the vendor. These alternative assumptions, and
the rational behind their use, will be offered in a later
section. Every attempt has been made to present the
analysis in sufficient detail so that the reader is
provided the ability to reconstruct any portion of the
economic analysis using their own assumptions or
cost information. Lastly, the level of detail achieved
by this analysis corresponds to an order-of-
magnitude estimate as defined by the American
Association of Cost Engineers. An order-of-
magnitude estimate has an accuracy of + 50 percent
to -30 percent.
As noted in Appendix B, ACI claims that the cost
savings are possible with the use of the Pyretron
technology in treating wastes with certain
characteristics. They further state that these savings
outweigh both the additional capital cost of the
Pyretron system and the cost of supplemental
oxygen, such that a user realizes a net economic
benefit. Our analysis suggests that this claim is valid
only under those conditions where the addition of the
Pyretron system leads to a significant increase in
waste throughput. The analysis presented in this
section shows that the degree to which the benefits
outweigh additional costs is dependent on a small
group of underlying cost and operating assumptions.
The engineering analysis of this system suggests that
the average waste throughput can be nearly doubled
when the unit is burning lower BTU wastes. (In fact,
the reader should note that during the SITE
demonstration, throughput was doubled even though
a higher heating value waste was used). Increased
throughput means less time on site, which translates
into reduced operating expenses. If operating cost are
particularly high, the result will be a significant
process cost savings. This is primarily a result of
better utilization of the capital (as represented by the
incinerator) coupled with decreases in total labor
costs.
4.2 Assumptions
Whether or not net savings are realized in a given
treatment project depends on the specific cost values
applicable to the above cost elements. In an economic
evaluation, the relative magnitude of cost savings
and additional costs will be greatly influenced by
assumptions made regarding:
The cost of capital
The cost of the incinerator
The labor rates
The number of incinerator operators needed
The cost of incinerator's auxiliary fuel
13
-------
The cost of oxygen
The cost of water
The total amount of waste to be treated
The cost categories listed below are common to all
SITE program economic analyses. Their impact on
the incremental cost or savings of the Pyretron
system are summarized below. Certain cost elements
were not analyzed for incremental cost or savings as
the addition of the Pyretron system had no impact on
these items under the given scenario. Those areas not
analyzed include:
Site Preparation
Permitting/regulatory requirements
Startup Costs
Effluent Treatment and Disposal
Residuals and Waste Shipping, Handling, &
Transport
Site Demobilization
Facility Modifications/Repair/Replacement: While no
incremental cost or benefit was calculated for this
analysis, the reader should be alert to the possible
need for making significant modification to their
incinerator to accommodate the Pyretron.
Those areas where this scenario suggested potential
incremental costs or benefits exist include the
following:
Capital Equipment: An incremental cost due to
the purchase of the Pyretron system. An
incremental benefit due to greater capital
utilization.
Labor: An incremental benefit due to greater
utilization.
Supplies and Consumables: An incremental
benefit due to lower fuel consumption. An
incremental cost due to oxygen consumption.
Utilities: An incremental cost due to increased
water requirements.
The remediation scenario which will serve as a base
case for our analysis, as well as the other
assumptions used in the economic analysis are
detailed in Table 2.
For the purpose of this analysis it was assumed that
the capital cost of he Pyretron system, labor rates,
and the cost of water are unchanged from those used
in the vendor claims section (Appendix B). The
analysis presented in this section focuses on
alternative assumptions regarding the cost of capital,
the capital cost of the incinerator, labor
requirements, overall utilization rates, auxiliary fuel
cost, and oxygen costs.
One of the trade-offs brought about by this process is
the substitution of oxygen for Supplemental fuel. The
reader should note that pure oxygen is a relatively
expensive raw material, and as such, it's use in
industrial applications is generally limited. Costs of
obtaining bulk quantities of oxygen can vary greatly,
and will be dependent on both total quantities needed
and availability of local sources. The least expensive
oxygen source would be under a long-term contract
and obtained via pipeline direct from an oxygen
generation plant. The most expensive source of
oxygen would likely be from suppliers who make
small bulk deliveries intermittently. For the purpose
of this analysis, the oxygen and propane cost used
reflect an average of selected 1988 government
contract prices as negotiated by the General Services
Administration (GSA) for federal facilities utilizing
similar quantities of these raw materials(4).
While this analysis assumes that the labor rates used
by the vendor are reasonable, the quantity of labor
needed to operate the incinerator was increased over
that suggested by the vendor. The rational was based
on past experiences with other conventional
incineration operations. First, we assume a 24
hr/day, 3 shift operation. It was assumed that one
senior engineer would supervise the overall
operation. Each shift would employ one operator and
one assistant. An additional 5 material handlers
would work the day and swing shift, and 3 material
handlers would work the night shift. It was further
assumed that per diem costs would be incurred for the
senior engineer, the three operators, and the three
assistants. No per diem costs were established for the
material handlers as it was assumed they would be
hired locally. A per diem cost of $75.00/day/person for
these 7 individuals was factored into the calculation.
Table 1 shows how the daily labor cost was computed,
highlighting labor rates, hours worked, and per diem.
For the purpose of this analysis, a total daily labor
cost of $3,825.80 was used.
4.3 Cost Evaluation
The remediation scenario and assumptions discussed
in Appendix B and 4.1 were used to determine the
following incremental costs or benefits of the
Pyretron system.
4.3.1 Capital Costs and Benefits
We first assume that the retrofit will occur on a
conventional incinerator that has an hourly
throughput, when operating at 100 percent
utilization, of 0.635 tonne/hr (0.7 ton/hr). Given that
an incinerator retrofitted with the Pyretron burner
has the potential to double throughput, the new
capacity, again at 100 percent utilization, is 1.27
14
-------
Table 1. Daily Labor Rate Calculation
Shift
Day
Swing0
Nightc
Job title3 ($)
SE
0
A
MH
O
A
MH
O
A
MH
No.
1
1
1
5
1
1
5
1
1
3
HrVday
8
8
8
40
8
8
40
8
8
24
Wage rateb
($)
46.00
30.00
17.00
15.00
33.00
18.70
16.50
36.00
20.40
18.00
Daily wage
($)
368.00
240.00
136.00
600.00
264.00
149.60
660.00
288.00
163.20
432.00
Per diem
75
75
75
0
75
75
0
75
75
0
($) Daily total
443.00
315.00
211.00
600.00
339.00
224.00
660.00
363.00
238.00
432.00
($)
3.825.80
a
b
c
SE = Senior Engineer; O = Operator; A = Asst. operator; MH = Material handler.
The wage rate is a loaded rate which assumes a multiplier of 2 on worker salary to account for fringe
administration costs, and profit. Engineering wage from (5).
The swing and night shifts reflect a 1 0 percent and 20 percent differential, respectively.
benefits,
Table 2. Cost Evaluation Assumptions
Parameter
Conventional system
Pyreton system
Common factors:
Incinerator size, (nominal total heat
input)
Quantity of waste treated
Heat content of waste
Incinerator capital cost
Auxiliary fuel and cost
Oxygen cost
Water costs
Equipment lifetime
Interest
Firing/feedrate (total heat input)
Propane heat input
Oxygen feed rate
Water feedrate
Pyretron capital cost
Royalty fee
Waste feedrate (100 percent utilization)
Utilization rate
Waste feedrate (adjusted utilization)
Job duration at given utilization rate
12 MW (40 MMBtu/hr)
4,472 tonnes (4,930 tons)
24.16 MJ/kg
$2,500,000
Propane at $3.86/GJ ($4.07/MMBtu)
$0.132/sm3 ($3.75/MSCF)
$0.0008/L ($0.003/gal)
15 years
9 percent/yr
12 MW(40 MMBtu)/hr)
7.41 MW (25.3 MMBtu)/hr)
0.635 tonne/hr (0.7 ton/hr)
80 percent
0.508 tonne/hr (0.56 ton/hr)
36724-hr days
15 MW (51 MMBtu)/hr)
6.36 MW (21.7 MMBtu)/hr)
1,760 sm3/hr
1,820 L/hr (480 gal/hr)
$100,000
$8.26/tonne ($7.50/ton)
1.27 tonne/hr (1.4 ton/hr)
75 percent
0.9525 tonne/hr (1.05 ton/hr)
196 24-hr days
15
-------
tonne/hr (1.4 ton/hr). If 100 percent utilization is
assumed to mean 24 hr/day, 365 days/yr, the
potential yearly throughput for the conventional
incinerator is 5,563 tonnes/yr (6,132 tons/yr), and
with the Pyretron retrofit in place, this throughput
could double to 11,126 tonnes/yr (12,264 tons/yr).
However, since 100 percent utilization is highly
unlikely in either case, the utilization rate has been
set at 80 percent for the conventional incinerator, and
75 percent in the case where the Pyretron system has
been adopted.
The reasons for the assumed difference in utilization
between the Pyretron and a conventional burner are
as follows. First, experience with the Pyretron during
the SITE demonstration indicated that it was not as
reliable as a conventional burner. While the
additional downtime experienced during the
demonstration may have simply been the result of
operational problems inherent in the first use of a
new technology, ACI personnel were onsite
throughout the demonstration to presumably solve
these problems and prevent significant downtime.
During routine use of the Pyretron ACI personnel
will probably not be onsite as much. It remains to be
seen how their absence will affect the downtime
experienced with the Pyretron.
Second, while the use of oxygen may solve
operational problems in situations where there is
excessive particulate carryover due to excessive gas
volumes, it will not increase operational reliability in
situations in which that was not a problem in the
first place. If the design of the incinerator minimizes
particulate carryover, or if the waste is oily and batch
fed in containers, particulate carryover may not be a
problem. The reliability of the incinerator with an air
burner may be high in such cases, and the added
complexity of the Pyretron may reduce it.
Thus, for future calculations the conventional
incinerator's adjusted maximum yearly throughput
is assumed to be 4,451 tonnes/yr (4,906 tons/yr). With
the Pyretron unit attached, the adjusted maximum
yearly throughput is assumed to be 8,344 tonnes/yr
(9,198 tons/yr).
The $100,000 fee charged by ACI as a capital cost of
the Pyretron system results in a annualized cost of
$12,406/year. This is calculated using a simple
capital-recovery factor formula where the assumed
interest rate is 9 percent and equipment life is 15
years. Using the adjusted maximum yearly
throughput for an incinerator retrofitted with the
Pyretron system, the result is an incremental capital
cost of $1.49/tonne ($1.35/ton) when viewed over the
life of the system operating at it's potential.
Assuming a capital cost of $2,500,000 for an
conventional incinerator, the capital-recovery
formula would indicate an apportionment of capital
costs at $310,150/yr (using the same 9 percent
interest rate and 15 year equipment life). Thus, the
yearly capital-recovery factor distributed over the
adjusted maximum yearly throughput treated by the
conventional system is $69.70/tonne ($63.22/ton). For
the Pyretron system, these costs are reduced to
$37.17/tonne ($33.72/ton). Adding the incremental
cost of the Pyretron unit to the calculated capital-
recovery estimate for the incinerator results in the
total Pyretron estimate, $38.66/tonne (35.07/ton).
Thus, incremental benefit arising from improved
capital utilization is the difference between the
conventional and Pyretron based units, or
$31.04/tonne ($28.15/ton).
4.3.2 Operating Costs and Benefits
The increase in throughput achieved when using the
Pyretron system will provide the incinerator operator
in this scenario with the ability to reduce the time he
needs to be on site. Specifically, the scenario assumed
that a total of 4,472 tonnes (4,930 tons) of
contaminated soil need to be treated. The
conventional incinerator would have to be on the job
site for 367 24-hour days to process the waste
(assun 'ng an 80 percent availability factor). The
Pyretron system, treating the same amount of waste,
would only need to be on site for 196 24-hour days
(assuming an 75 percent availability factor). Based
on the daily labor cost of $3,825.80, the total project
labor cost using conventional incineration would be
$1,404,068.60. By installing the Pyretron system,
and reducing the number of operating days, the total
project labor cost would be reduced to $749,856.80.
The difference between the two results in a savings of
$654,211.80. Thus, there is an incremental benefit
due to labor savings of $146.29/tonne ($132.70/ton).
For a conventional incinerator of the assumed size,
the supplemental fuel (propane) consumption rate
was calculated to be 7.41 MW (25.29 MMBtu/hr).
Using average GSA propane price of $3.86/GJ ($4.07
MMBtu) described above, the result is a fuel cost of
$102.93/hr of operation. With an adjusted hourly
throughput (at 80 percent utilization) of .508
tonne/hr (0.56 tons/hr), this converts to fuel costs of
$202.62/tonne ($183.80/ton). The corresponding
supplemental fuel (propane) consumption rate for the
Pyretron system is 6.36 MW (21.71 MMBtu/hr).
Again, using the average GSA propane price, the
result is a fuel cost of $88.35/hr of operation. With an
adjusted hourly throughput (at 75 percent
utilization) for the Pyretron incinerator of 0.9525
tonne/hr (1.05 tons/hr) this converts to a fuel costs of
$92.76/tonne ($84.15/ton). This results in an
incremental benefit due to fuel savings of
$109.86/tonne ($99.65/ton).
The oxygen supply rate in this scenario was
calculated to be 1,760 sm3/hr (62 MSCF/hr). Using
the average GSA oxygen cost of $0.132/sm3
16
-------
($3.75/MSCF), the oxygen cost for the Pyretron
incinerator is $232.50/hr of operation. At the adjusted
throughput rate of .9525 tonne/hr (1.05 tons/hr) this
converts to an oxygen cost of $244.09/tonne
($221.43/ton). Since the conventional incinerator
uses no oxygen, this cost is considered an incremental
cost. Water injection costs for the Pyretron system
remain at $1.00/tonne ($0.90/ton).
The last operating cost to consider is the royalty fee
charged by ACL It is a flat rate of $8.26/tonne
($7.50/ton) of waste treated. This is an incremental
cost for the Pyretron system.
4.3.3 Benefit Summary
Table 3 summarizes the incremental treatment
savings and < costs > projected for the Pyretron
system under the assumptions presented above.
Shown for comparison is the evaluation based on
vendor-supplied cost data which is discussed in
Appendix B.
The data in Table 3 show that for the waste
treatment application evaluated, use of the Pyretron
system offers significant cost savings over
conventional incineration in the case where waste
throughput can be increased.
While not explicitly considered within this analysis,
the reader needs to be alert to a number of factors
which will alter the results of this analysis. These
include the following:
Only a complete engineering analysis for a particular
incinerator configuration will indicate to degree to
which increases in throughput are possible. This is a
critical assumption as all subsequent cost
calculations are dependent on this fact.
Incinerator operators who consider retrofitting their
equipment to accommodate the Pyretron should take
care in considering the cost of equipment
modifications.
This analysis suggests that the degree to which one
will enjoy incremental cost savings is heavily
influenced by the labor requirement and wage rates.
Different assumptions regarding the cost of capital
(interest rates), the capital cost of the incinerator,
and the methods for apportioning capital cost (i.e.,
capital recovery factor) will all impact the potential
for incremental savings.
The trade-off between oxygen and the supplemental
fuel source is a direct result of their underlying unit
cost. Low oxygen costs coupled with high fuel costs
will result in the most dramatic savings. High
oxygen costs coupled with low fuel cost may result in
further incremental costs, offsetting savings in other
areas.
17
-------
Table 3. Summary of Incremental Savings (< Costs >) for the Pyretron System
Cost Assumption Scenario
Increase cost element
Total
$/tonne
Agency3
Vendor*5
32.31
Total incremental project savings3 $144,400
° Treating 4,472 tonnes (4,930 tons) of waste
t> See Appendix B.
48.66
$218,000
$/ton
Agency3
29.31
Vendor15
Capital costs
Initial ACI fee
Increase in capital utilization
Operating costs
Labor
Supplies
Propane
Oxygen
Water
Royalty
-1.49
31.04
146.29
109.86
-244.09
-1.00
-8.30
-1.5
54.03
97.28
90.86
-182.71
-0.99
-8.30
-1.35
28.15
132.70
99.65
-221.42
-0.90
-7.50
-1.40
49.12
88.44
82.60
-166.10
-0.90
-7.50
44.24
References
1. "FY 1988 ORD Summary Report," Hazardous
SITE Control Division, Office of Emergency and
Remedial Response, USEPA Washington B.C.
March 1989.
2. Linak, W.L, J. McSorley, J. Wendt and J. Dunn.
"Rotary Kiln Incineration: The effect of Oxygen
Enrichment on Formation of Transient Puffs
During Batch Introduction of Hazardous
Wastes." U.S. EPA, Research Triangle Park, NC.
December 1987. PB88140546.
3. "Technology Evaluation Report SITE Program
Demonstration Test, American Combustion
Pyretron Thermal Destruction System at the
U.S. EPA Combustion Research Facility."
EPA/540/5-89/008. U.S. EPA, Cincinnati, Ohio.
March 1989.
4. General Services Administration (GSA) 1988
government contract price catalog as documented
in memo, G. Evans, EPA/RREL, to L. Staley,
EPA/RREL, November 15,1988.
5. "Economic Survey Report." 1987, American
Institute of Chemical Engineers, New York,
1988.
18
-------
Appendix A
Process Description
This section provides an overview of the Pyretron
Thermal Destruction System. A brief description of
the technology is provided in Section A.I; Section A.2
describes the innovative features of the technology
and compares the Pyretron system to conventional
burners.
A.1 Treatment Process
The Pyretron Thermal Destruction System is an
innovative burner system designed to be used in
conjunction with a conventional transportable or
fixed incinerafor. The system provided for the SITE
demonstration consisted of two burners, one installed
in the primary combustion chamber (kiln) and one
installed in the afterburner; valve trains for
supplying these burners with controllable flows of
auxiliary fuel, oxygen, and air; a computerized
process control system; an oxygen supply system; and
a kiln water injection system. A schematic of the
system is shown in Figure A-l. The Pyretron burners
use a proprietary parallel combustion approach based
upon the independent introduction of either pure
oxygen, air, or oxygen-enriched air.
The Pyretron burners use the staged introduction of
oxygen to produce a hot luminous flame which
efficiently transfers heat to the solid waste which is
fed separately to the kiln. Oxygen, propane, and
oxygen-enriched air enter the burner in three
separate streams each concentric to one another. A
stream of pure oxygen is fed through the center of the
burner and is used to burn propane in a
substoichiometric manner. This produces a hot and
luminous flame. Combustion is completed by mixing
these hot combustion products with the stream of
oxygen-enriched air introduced around the outside of
the flame envelope.
In a typical Pyretron system Superfund site waste
treatment application, many of the equipment
systems required are the same as those required by a
conventional incinerator treatment process. These
are:
Waste pretreatment and containerization (i.e.,
drumming) equipment
Waste and residuals analysis facilities
Containerized waste ram feeder
Primary incineration chamber and afterburner
chamber
Auxiliary fuel supply system
Air pollution control system (APCS)
Residuals (incinerator ash and APCS residuals)
treatment and disposal equipment
Equipment systems unique to a Pyretron system
application would include:
Special Pyretron system auxiliary fuel burners
Special burner auxiliary fuel, air, and oxygen
flow control system
Proprietary combustion process control system
Oxygen supply system
Kiln water injection system for high heat content
wastes
In a typical Pyretron system application, waste
contained in drums will be batch charged to the
rotary kiln of a rotary kiln incineration system at a
specified charge interval. Organic contaminants in
the waste will be volatilized and destroyed via
combustion in the vapor phase. Most of the inorganic
Waste fraction will traverse the kiln and be
discharged as kiln ash. Combustion gas will exit the
kiln and flow to an afterburner. The afterburner
exists to ensure that essentially complete destruction
of organic contaminants occurs. Combustion gas from
the afterburner is quenched, then directed to an Air
Pollution Control System (APCS). The APCS
removes particulate and any acid gases such as HC1
resulting from various waste constituents. The APCS
residual stream will either be scrubber blowdown
from wet scrubber systems or flyash combined with
any acid gas dry sorbent from dry APCSs. These
residuals will not be measurably different from a
Pyretron system application than from conventional
incineration.
A. 2 Innovative Features
The Pyretron system represents an innovative
combustion approach for application to an
19
-------
Figure A-1. Pyretron Thermal Destruction System process diagram.
incinerator. One feature unique to the Pyretron
system is its dynamic use of pure oxygen to supply a
portion of the combustion oxygen needed to destroy
organic waste contaminants. "Dynamic use" means
that the amount of pure oxygen supplied can be
changed in a preset manner based upon the operator's
knowledge of the combustion behavior of the waste
feed. In this system, oxygen can be used to augment
or replace a portion of the combustion air feed to an
incinerator's burners.
Although EPA was not provided with documentation
on the oxygen flow control system supplied for the
SITE demonstration because ACI considers it
proprietary, the system worked as follows during the
demonstration tests (1). The flowrate of oxygen into
the kiln through the Pyretron changed when either of
the following four events occurred.
1. Excessive pressure occurred in the kiln chamber
and was measured at the kiln exit.
2. Excessive CO was produced in the kiln and was
measured at the kiln exit by a CO monitor.
3. Low levels of oxygen occurred in the kiln and
were measured at the kiln exit by an oxygen
monitor.
4. A certain amount of time had elapsed
(approximately 30 seconds) since the activation of
the ram feeder to batch charge waste into the
kiln.
In response to the first event, the flowrate of air to the
burner was reduced to a preset level (or series of
levels if needed). The flowrate of oxygen was
correspondingly increased in order to keep the overall
level of oxygen in the kiln at a constant level.
If either of the remaining three events occurred, the
oxygen flowrate was increased in a (preset) stepwise
manner. This stepwise increase occurred
approximately 30 seconds after activation of the ram
feeder even if no fluctuations in CO or oxygen level
were detected. There were many feed cycles during
the demonstration in which no such fluctuations
occurred. At the end of a feed cycle or when the other
triggering conditions no longer existed, the oxygen
and air levels would return to their "prevent" levels
in a similar stepwise manner.
The use of oxygen to enrich the combustion air
stream can also be considered an innovative feature
of the Pyretron. It provides one additional process
parameter which can be varied to maintain optimum
operating conditions within the incinerator. The
Pyretron is capable of replacing up to 50 percent of
the combustion air stream with oxygen.
A.3 CRF Design Considerations
The Pyretron provided by American Combustion was
customized for use at the CRF. The burner
penetrations in the CRFs Rotary Kiln system were
too small, in ACI's opinion, to accommodate a staged
burner design typical of what would be used for NOX
suppression. As a result, the burner demonstrated
under the SITE program may have produced higher
NOX emissions than would be the case had the burner
penetrations been larger.
While it may be true that a different Pyretron would
have produced less NOX, there is no basis for
concluding that a different Pyretron would have
achieved the large throughput increases that the
Pyretron demonstrated at the CRF did.
20
-------
Appendix B
Vendor Claims
This section summarizes the claims made by the
developer about the technology under consideration.
EPA does not necessarily agree with all of the
statements made in this section. EPA's point of view
was discussed in Sections 3 and 4 of this report.
American Combustion, Inc. (ACI) the developer of
the Pyretron Thermal Destruction System, states
that the Pyretron system offers three advantages
over conventional rotary kiln incineration in treating
high organic content wastes. These are:
The Pyretron system will be capable of reducing
the magnitude of transient high levels of CO,
unburned hydrocarbon, and soot ("puffs") that
can occur with repeated batch charging of a high
heat content waste to a rotary kiln.
The Pyretron system will allow increased waste
feedrate to the kiln while still achieving the
hazardous waste incinerator performance
standards for POHC destruction and removal
efficiency (DRE) and particulate emissions.
The Pyretron system is more economical than
conventional incineration.
Discussion of the first two claims is presented in
Section B.I. Section B.2 presents an economic
analysis supporting the third claim based on vendor
supplied cost data.
B.1 Incinerator Operational Benefits
The first ACI claim regarding the Pyretron Thermal
Destruction System is that the Pyretron system will
be capable of reducing the magnitude of transient
puffs that can occur with repeated batch charging of a
high heat content waste to a rotary kiln. The basis for
this claim follows. Rotary kiln incinerators are
unique in that they are designed to allow a portion of
their waste load to be introduced or charged to the
system in a batch rather than continuous mode. For
organic, heating value-containing wastes, a portion
of the heat input to the system is correspondingly
introduced in a batch mode. Typically, containerized
waste, in cardboard, plastic, or punctured steel drums
is charged to the kiln at established intervals. Upon
entry to the kiln, the waste containers are heated
until they rupture or burn. This then exposes the
waste contents to the hot kiln environment. Volatile
organic material then rapidly vaporizes and reacts
with available oxygen in the combustion gas.
However, if the volatilization of organic material is
more rapid than combustion oxygen can be supplied
to the kiln, incomplete combustion can result. This
can lead to a "puff of incompletely destroyed organic
material .exiting the kiln. In most instances, this puff
will be destroyed in the system's afterburner. In fact,
afterburners are included in rotary kiln incinerator
systems for this very reason. However, if the puff is of
sufficient magnitude, insufficient excess oxygen
and/or residence time may exist in the afterburners
to allow its complete destruction.
In conventional incineration systems, the only way to
ensure that sufficient oxygen exists in the kiln for
complete waste oxidation is to increase the air
flowrate to the kiln. This can either be accomplished
by steadily firing the kiln burner at higher excess air
than needed to burn the burner fuel, or by
dynamically increasing the air flowrate in
anticipation of a puff. In either instance, an increased
air flowrate adds both increased oxygen for waste
combustion and increased nitrogen. The increased
diluent nitrogen flow is detrimental to complete
waste destruction for two reasons. Its presence in the
combustion gas volume decreases kiln combustion
gas residence time and, since it must be heated, it
decreases combustion gas temperature.
In contrast, the Pyretron system offers the ability to
dynamically increase the amount of oxygen in the
combustion process in anticipation of a puff while not
adding diluent nitrogen. Thus, kiln temperature can
be more easily maintained and additional oxygen
needed for waste puff destruction can be introduced
with less effect on combustion gas volume, hence
combustion gas residence time, than possible with air
alone. A programmed system response is possible in
which oxygen flow to the burner is increased after a
suitable lag time after batch charge addition. This
extra oxygen, without diluent nitrogen, is available
for waste puff oxidation. With this additional kiln
condition control flexibility, the magnitude of
transient puffs should be reduced as compared to
21
-------
similar operating conditions with conventional
incineration.
An additional point which ACI makes is that new
EPA regulations of CO levels will require existing
incinerators to implement combustion and control
equipment which is as sophisticated as the Pyretron
system. These regulations will require incineration
operators to continuously monitor CO and compute
rolling averages as well as shut-off the waste feed
while continuing auxiliary fuel input when CO levels
are exceeded.
The second ACI claim regarding the Pyretron system
is that its use will allow increased waste throughput
in a rotary kiln system while maintaining
acceptable, in-compliance, incinerator operation. The
basis for this claim follows from the basis of the first
claim. The maximum feedrate of a high organic
content waste in a conventional incinerator is
determined by the onset of transient puffs which
survive the afterburner. When this occurs, waste
constituent destruction is less than complete, and
eventually falls below the regulation mandated 99.99
percent hazardous constituent destruction and
removal efficiency.
The discussion supporting the first claim noted that,
since the additional oxygen to support waste
combustion would be supplied without diluent
nitrogen in the Pyretron system, incineration
residence times would be greater for a given waste
and auxiliary fuel feedrate; therefore, incineration
destruction efficiency would be greater. Thus, a
feedrate that produced unacceptable transient puffs
under conventional incineration would not with the
Pyretron system. Correspondingly, the onset of
unacceptable transient puff generation under
Pyretron operation would occur at a higher waste
feedrate. Thus, acceptable operation at higher waste
feedrates (or throughputs) should be possible with
the Pyretron system.
B.2 Process Economic Evaluation
The third ACI claim noted in the introduction to
Appendix B was that the Pyretron system is more
economical than conventional incineration. The basis
for this claim follows from the bases for the first two
claims. Since the Pyretron system uses oxygen for a
portion of the waste oxidant (instead of air), a given
set of incineration temperatures can be maintained
with less auxiliary fuel feed than possible with
conventional incineration. Less diluent nitrogen is
fed, thereby obviating the need to heat this diluent
nitrogen to combustion temperature. Thus, auxiliary
fuel use per unit of waste treated is less for the
Pyretron system than for conventional incineration.
In addition, if higher waste feedrates can be
employed in a given combustor with the Pyretron
system, then the treatment time required per unit of
waste is decreased. This affords further operating
cost savings, as well as capital recovery costs per unit
of waste treated.
ACI claims that these cost savings more than offset
Pyretron system capital costs and oxygen purchase
costs. The claim is supported by the following
economic analysis. The analysis is based on cost and
pricing data supplied by ACI along with certain
assumptions made about the type and quantity of
waste treated by the system.
B.2.1 Method and Assumptions
The operating characteristics of a conventional RKS
and the same kiln retrofitted with the Pyretron
system were determined during the SITE
demonstration tests discussed in Appendix C. The
SITE demonstration was performed on a 880 kW (3
million Btu/hr) pilot-scale rotary kiln incinerator.
The waste used was a mixture of contaminated soil
from the Stringfellow Superfund site (approximately
40 percent, by weight) and the listed waste K087,
decanter tank tar sludge from coking operations
(approximately 60 percent, by weight). The mixture
had a heat content of about 24.16 MJ/kg (10,410
Btu/lb). As detailed in the Technology Evaluation
Report (2), operating parameters were varied to
determine the optimum throughput, fuel feedrate,
and air and oxygen feedrates. These optimum values
are summarized in Table B-l. In keeping with EPA
policy, the measurement units reported use SI units
as the primary citation with English units in
parentheses. Unit conversions used in this section
are summarized in Table B-2.
Using the optimum operating conditions, the ratio of
heat input from waste to heat input from fuel was
determined for the two treatment approaches,
conventional incineration and the Pyretron system.
These ratios were then used to determine waste
throughput, fuel, and oxygen consumption for a 12
MW (40 MMBtu/hr) nominal total heat input RKS.
This size RKS was selected as being representative of
transportable systems now in use.
The Pyretron system employs water injection to
maintain the correct kiln temperature when feeding
high heating value wastes. The addition of this heat
sink also enables the Pyretron system to handle a
higher heat content loading rate per nominal kiln
capacity. In the demonstration tests, an 880 KW (3
MMBtu/hr)-rated RKS was able to handle 1.1 MW
(3.8 MMBtu/hr) of total heat input with the Pyretron
system in operation. For the economic analysis then,
a nominal 12 MW (40 MMBtu/hr) RKS was assumed
capable of handling 15 MW (51 MMBtu/hr) of total
waste and auxiliary fuel heat input with the
Pyretron system applied.
22
-------
Table B-1. Optimum Operating Parameters Determined in the Demonstration Test
Program3
Parameter
Conventional system
Pyretron system
Waste feedrate
Propane heat input
Oxygen feedrate
Waste heat input
Total heat input rate
Fraction of heat input from fuel
47.7 kg/hr(l05 Ib/hr)
550 kW (1.9 MMBtu/hr)
320 kW (1.1 MMBtu/hr)
870 kW (3.0 MMBtu/hr)
0.63
Fraction of heat input from waste 0.37
95.5 kg/hr (210 Ib/hr)
480 kW (1.6 MMBtu/hr)
131.4 sm3/hr (4,640 scf/hr)
640 kW (2.2 MMBtu/hr)
1,120 kW(3.8 MMBtu/hr)
0.43
0,57
a Demonstration tests performed in 880 kW (3 MMBtu/hr) pilot-scale rotary kiln incinerator.
Table B-2. Unit Conversion (Si-English) Used in this
Analysis
1 kg = 2.20 Ib
1 metric ton (1 tonne) = 1,000 kg = 2,200 Ib = 1.10 tons
1 sm3 = 35.31 scia
1 MJ/kg = 430.8 Btu/lb
1 kW = 3,412 Btu/hr
1 J = 1,055 Btu
a Denotes standard conditions of 1 atm and 15.6°C (60°F).
B.2.1.1 Treatment Cost Assumptions
As discussed above, ACI claims that the Pyretron
system can be used to enhance the performance of a
conventional RKS. In this context, the Pyretron
system is affected by the same factors as any other
incineration technology would be, such as type of
waste, cost of auxiliary fuel, labor rates, etc. Because
this analysis treats only incremental costs, these
common factors have been ignored.
Use of the Pyretron system results in both benefits
and additional costs compared to a conventional
system. Briefly, the Pyretron system incurs the cost
of purchasing oxygen, water for kiln temperature
control, and extra capital costs (as discussed below).
Benefits of the Pyretron system are lower auxiliary
fuel costs and higher throughput for certain waste
types. This allows lower labor costs per ton of waste
treated and better utilization of capital cost for such
wastes.
In essence, ACFs claim is that the benefits outweigh
the costs for appropriate waste types. This economic
analysis was performed to determine the validity of
this claim. The primary data required to perform the
analysis were:
The incremental capital cost of the Pyretron
system
The cost of incinerator operator labor
The cost of incinerator auxiliary fuel
The cost of oxygen
The cost of water
To perform the analysis, a hypothetical remediation
scenario was developed. For the conventional system,
a job duration of 1 year was selected. Based on the
estimated throughput capacity of a conventional
RKS burning the same waste as that used in the
demonstration test, the total mass of waste treated
was determined. It should be noted that the heat
content of the waste used in the demonstration test
was higher than what may typically be found at a
Superfund site, although Superfund site wastes with
such heat content are likely to exist. Many Superfund
site wastes are oily sludges with significant heat
content. However, the most common Superfund site
waste is a contaminated soil with low total organic
content. The high waste heat content had the effect of
reducing the throughput capacities of both systems to
a level below that possible with a very low heat
content waste.
The total mass of waste treated was calculated
assuming 24-hours per day, 7 days per week, and 52
weeks per year operation, and an availability factor
of 80 percent for a conventional incinerator system.
That is, it was assumed that the conventional RKS
would operate, on average, 80 percent of the time or
6,900 hours a year. The demonstration test program
determined that 37 percent of the total heat input to
the conventional RKS came from the waste. For a
nominal 12 MW (40 MMBtu/hr) incinerator burning
a waste with a heat content of 24.16 MG/kg (10,410
Btu/lb) a throughput of 640 kg/hr (0.7 tons/hr) is
implied. Multiplying the number of operating hours
by the throughput yields the total mass of waste
treated in the scenario, 4,480 tonnes (4,930 tons).
The demonstration test program determined that the
Pyretron system allowed an increase in heat input to
the incinerator of 28 percent. Thus, an incinerator
rated at a nominal 12 MW (40 MMBtu/hr) could
operate at 15 MW (51 MMBtu/hr). In addition, the
23
-------
demonstration showed that the Pyretron system
allowed 57 percent of the heat input to come from the
waste. The net effect of these two factors is the
doubling of throughput for the Pyretron system over
conventional incineration. A total of 4401 hours
(183.4 24-hr days) are required to treat the 4,480
tonnes (4,930 tons) of waste assumed in this scenario.
The treatment project durations and throughput
capacities of the two systems directly affect labor
costs and capital utilization. Along with fuel, oxygen,
and water costs, these factors form the basis for
determining the incremental cost or benefit of the
system.
The assumptions made in assigning treatment costs
for conventional incineration and a Pyretron
application are discussed in the following
paragraphs. Many of the costs associated with the
application of a conventional RKS are identical to
those costs that would be incurred by a Pyretron
RKS. In those cases, no incremental costs (or
benefits) would be expected. Cost categories where
this is true have been so indicated.
Design and Application Engineering Costs
Design and application engineering costs include site
preparation, permitting and regulatory, and capital
equipment costs. Assumptions for these are discussed
in the following paragraphs.
The site preparation cost category includes site
design/layout for development, surveys/site
investigations, legal searches, access rights and
roads, preparation for support facilities,
decontamination trailers, utility connections,
foundations, auxiliary buildings, and all other
expenses that would be incurred in preparing the site
for the installation and operation of the technology.
All of these costs would be common to both
conventional incineration and the Pyretron system.
In addition, the Pyretron system would include all
costs incurred by the application of a conventional
incinerator. Thus, the Pyretron system does not incur
incremental cost nor offer any incremental benefit.
The permitting/regulatory cost category includes all
the costs incurred in satisfying the applicable
regulatory requirements, such as developing the
Safety, Health and Emergency Response Plan
(SHERP). Although such plans must accommodate
the use of oxygen, it is not expected that the addition
of the Pyretron system to an RKS will measurably
increase or decrease these costs. Thus, there is no
incremental cost or benefit.
For the purpose of this economic analysis, capital
equipment costs include all one-time costs associated
with applying the technology to a remediation site.
These include procurement and relocation costs for
the RKS, waste and material handling equipment,
and support facilities.
ACI has indicated that it does not intend to sell the
Pyretron system on the basis of ACFs cost to produce
the equipment but on a basis of the improved
performance of the incineration operation (3). For an
incineration system of the size used in this analysis,
ACI estimates that the Pyretron TDS would be
provided for an initial fee of approximately $100,000,
depending upon the required modifications to the
computerized process controller, and a royalty of
$7.50 per ton of waste fed through the system. The fee
would cover assistance from ACI in performing the
trial burn, training of operators on an ongoing basis,
maintenance of the equipment, and assistance in
optimizing the system for a given waste stream. For
this analysis, the $100,000 fee has been defined to be
the incremental capital cost, and the royalty fee has
been allocated to incremental operating costs. The
higher throughput possible with the Pyretron system
also allows the capital invested in the base
incinerator system to be used more efficiently than in
a conventional application. This improvement in
capital utilization is discussed in detail later in this
section. All other differences in capital equipment
costs (as defined above) were considered negligible.
Operating Costs
Operating costs include startup, operating labor,
operating supplies, and utilities costs. Assumptions
for these are discussed in the folio wing paragraphs.
Due to the increased complexity of the Pyretron
system it was assumed that startup activities will
consume an extra week of operating time over the 1
week estimated for a conventional system. However,
this cost was assumed to be included in the fee and
royalty charges.
It is expected that neither the number of operating
personnel nor the average labor rate would be
different for the Pyretron system as compared with a
conventional RKS. However, a cost benefit will
accrue by using the Pyretron system due to the
higher throughput. This will allow the same mass of
waste to be treated in a shorter period of time; thus,
fewer labor hours will be required per weight of
waste treated. The labor categories and rates used to
determine the daily crew costs are summarized in
Table B-3.
The demonstration test used propane as the auxiliary
fuel for both the conventional and Pyretron systems.
Many fuels (and wastes) may be used as auxiliary
fuels at a remediation site. However, for the purposes
of this analysis it was assumed that propane would be
used. In addition, the heat content of Superfund site
wastes can vary over a broad range. In this analysis,
it was assumed that waste with the same heat
24
-------
Table B-3. Crew Costs - Daily Loaded Rate3 (24-Hour
Operation)
1 Supervising Engineer, 8 hr/day @ $46/hr
1 Operator (each shift), 24 hrs/day @ $30/hr)
1 Assistant (each shift), 24 hrs/day @ $l7/hr
2 Material handlers (each shift), 24 hrs/day @ $15/hr
Labor
Shift
Hours
Category Rate
Cost ($)
Day
Swingb
Graveyard0
Total
8
8
8
16
8
8
16
8
8
16
SE
O
A
MH
O
A
MH
0
A
MH
46.00
30.00
17.00
15.00
33.00 .
18.7
16.50
36.00
20.00
18.00
368
240
136
240
264
150
264
288
163
288
$240 M
24-hr day
a Loaded rate assumes a multiplier of two on worker salary to
account for fringe benefits, overhead, administrative costs, and
profit.
b 10 percent shift differential for swing
c 10 percent shift differential for graveyard.
content as the waste used in the demonstration test
would be treated.
For a conventional RKS of the assumed size, a fuel
(propane) consumption rate of 7.41 MW (25.3
MMBtu/hr) was calculated. The waste throughput
was estimated to be 640 kg/hr (0.7 tons/hr). For the
Pyretron system the corresponding fuel (propane)
consumption rate was 6.36 MW (21.7 MMBtu/hr).
The throughput of the Pyretron system was
estimated to be 1,270 kg/hr (1.4 tons/hr). Propane was
assumed to cost $5.70/GJ ($6.00/MMBtu) per ACI's
recommendation (3). One of the main elements of the
Pyretron system is the dynamic use of oxygen in the
combustion process. The oxygen supply rate was
calculated to be 1,760 sm3/hr (62 MSCF/hr), and
oxygen was assumed to cost $0.088/sm3
($2.50/MSCF) per ACI's recommendation (3). The
Pyretron system also requires water injection to
maintain the appropriate kiln temperature. The
water consumption rate for this system was
estimated to be 1,820 L/hr (480 gallons/hr). Water
costs were assumed to be $0.0008/L ($0.003/gal).
Makeup requirements of the pollution control system
were assumed to be unchanged. All other supplies,
were assumed to be common to both systems;
therefore, there was no impact on incremental costs
or benefits.
VENDOR EDITORIAL COMMENT. AT THE
VENDOR'S REQUEST, THE FOLLOWING
COMMENTS ARE REPEATED VERBATIM FROM
A MEMORANDUM FROM MARK ZWECKER TO
EPA DATED MARCH 24,1989
The analysis included in the report shows untypically
high fuel costs when test result are scaled to a 40
MMBtu per hour incinerator. Therefore, it is obvious
that the methods used for scaling need to take into
account additional factors. Specifically this analysis
must take into account the untypical length/diameter
ratio of the CRF kiln which results in rates of heat
loss that are unusually high when compared to heat
losses for a commercial incineration system.
The length/diameter ratio of the CRF kiln is between
2 and 2.5, while this ratio for a typical system varies
from 5 to 7. Based on these ratios and typical heat
inputs for commercial incinerators, the outside
surface area of the CRF kiln per unit heat release is
in the range of 2.3 to 2.8 times higher than for a
commercial incineration system. Since the heat loss
through the walls is directly proportional to the wall
area, the relative heat losses for the CRF ,kiln should
be expected to much higher than for a typical
commercial incineration system.
Heat losses from commercial incinerators typically
amount to about 5 percent of the total heat input
(EPA's Handbook for Hazardous Waste Incineration).
Based on the increased relative surface area of the
CRF system, heat losses for this system are
approximately 13 percent. This number is
representative and has been verified by heat balances
performed by ACI at the initial stages of testing.
Therefore, the heat losses for the CRF kiln are
approximately 160 percent higher than a typical
system. These large heat losses and the high excess
air levels required for incineration will significantly
impact fuel consumption and can lead to very high
estimates of fuel costs when scaling up test data if not
accounted for in the calculations. ACI's analysis
shows that by applying these factors correctly when
scaling to a commercial size unit much more realistic
estimates of fuel costs can be obtained.
End of Vendor Editorial Comments
Utility costs such as telephone, drinking water, and
sanitary facilities are not expected to differ between
the two systems. Electricity costs for the air supply
fan may change, but for the purposes of this analysis
this incremental cost was assumed to be negligible.
Effluent Treatment and Disposal
The effluent streams for both systems consist of flue
gas, air pollution control system discharge (e.g.,
scrubber blowdown), and kiln ash. The discharge of
25
-------
flue gas entails no cost, and the total quantity of air
pollution control system discharge and kiln ash is
expected to remain the same. Therefore, the
incremental costs for this category between the two
systems was assumed to be negligible.
In addition, there are costs associated with the
preparation of the residual waste for shipping,
interim storage, waste disposal, and loading and
transportation costs. The characteristics and total
quantity of residual waste produced by the two
systems is assumed to be the same, only the rate at
which it is produced is different. Because the costs
detailed above are not time dependent, no
incremental cost/benefit is expected.
Analytical Costs
It was assumed that the Pyretron equipped RKS
would require the same analytical monitoring
equipment and techniques as a conventional RKS.
Any additional monitoring equipment costs were
assumed to be included in the incremental capital
costs. Also, it was assumed that no increase or
decrease in the frequency of analysis would be
involved. That is, analysis costs are incurred on a
per-ton-treated basis as opposed to a time basis.
Expenses incurred under analysis costs include site
demonstration monitoring, environmental
monitoring, Quality Assurance/Quality Control, and
reporting requirements. Since none of these cost
items is likely to be different between the two
systems, no incremental cost or benefit is expected.
Facility Modifications!RepairlReplacement
This cost category includes design adjustments,
facility expansion, and equipment parts and
replacement. These costs were assumed to be covered
by ACI's initial fee and royalty payment.
Modifications, repairs, or replacement of parts on the
incinerator that are not covered by the vendor are
common to both systems and were not included in the
determination of the incremental costs.
S//e Demobilization
Unlike startup costs, it was assumed that the
Pyretron system would incur the same
demobilization costs as a conventional RKS. Thus, no
incremental cost or benefit is expected for shutdown,
site and equipment decontamination, site
restoration, permanent storage, or site security costs.
8.2.7.2 Basis for Determining Incremental Cost
or Benefit
To determine the incremental cost or benefit, each
cost category was normalized to a dollars-per-ton-of-
waste-treated basis. This was accomplished by
dividing the individual costs by the total mass of
waste treated in the scenario. Incremental capital
costs were determined by first converting the capital
cost (present value) to an annualized cost using the
capital recovery formula:
Annual cost = P*-
where
Ki+i)"
a+un-i
P is the present value of the investment,
i is the interest rate per period and
n is the number of periods
The $100,000 fee which would be paid to ACI for the
Pyretron system was converted to an annual cost
assuming a 15-year equipment life (this is considered
reasonable for a transportable rotary kiln system), no
salvage value, and an interest rate of 11 percent per
annum. The Pyretron system allows a higher
throughput for a given size incinerator. Assuming
that the system has the same equipment life, this
improves the utilization of base incinerator capital.
That is, more tons of waste could be treated for the
same capital cost. The improvement in capital
utilization due to increased throughput was
calculated as an annual cost (actually an annual
benefit) by determining the annual capital cost of the
12 MW (40 MMBtu/hr) RKS assumed in the scenario,
and dividing this figure by the estimated annual
throughput for the conventional system. The capital
cost of a system this size was assumed to be
$3,500,000. As with the ACI fee, the capital cost was
converted to an annual cost assuming an equipment
life of 15 years, no salvage value, and an interest rate
of 11 percent. This step was then repeated using the
estimated annual throughput of the Pyretron system.
The difference between these two values ($/ton)
represents the incremental cost benefit due to
improved capital utilization gained by using the
Pyretron system.
B.2.1.3 Cost Assumption Summary
The cost categories and their impact on the
incremental cost or benefit of the Pyretron system are
summarized below:
Design and Application Engineering Costs
- Site preparation costs: no incremental cost or
benefit
- Permitting/regulatory requirements: no
incremental cost or benefit.
- Capital equipment costs: An incremental cost of
$100,000 due to ACI's fee. An incremental benefit
due to the greater capital utilization caused by
higher throughput.
26
-------
Operating Costs
- Startup costs: no incremental cost or benefit.
- Labor costs: an incremental benefit due to higher
throughput.
- Supplies: An incremental benefit due to lower
fuel consumption and an incremental cost due to
the cost of purchasing oxygen.
- Utilities: no incremental cost or benefit
Effluent Treatment and Disposal: no incremental
cost or benefit.
Residuals and Waste Shipping, Handling and
Transport: no incremental cost or benefit.
Analytical Costs: no incremental cost or benefit.
Facility Modifications/Repair/Replacement: no
incremental cost or benefit.
Site Demobilization: no incremental cost or
benefit.
The remediation scenario, the assumptions discussed
above, and the other assumptions used in the
economic analysis are detailed in Table B-4.
B.2.2 Cost Evaluation
Based on the remediation scenario and assumptions
discussed in Section B.2.1, the following incremental
costs or benefits generated using the Pyretron system
were determined.
B.2.2.1 Capital Costs and Benefits
The $100,000 fee charged by ACI to use the system
results in a annualized capital cost of $13,906/year.
Based on an estimated throughput for the Pyretron
system of 8,918 tonnes of demonstration test-type
waste per year (9,811 tons/year) this results in an
incremental capital cost of $1.56/tonne ($1.42/ton).
Based on an 80-percent availability factor, the
conventional RKS was estimated to have an annual
throughput of 4,480 tonnes (4,930 tons). The Pyretron
system was estimated to have a throughput of 8,911
tonnes (9,833 tons). Based on a capital cost of
$3,500,000, the capital cost per tonne of waste treated
for the conventional system was $108.64/tonne
($98.73/ton). The capital cost per tonne of waste
treated for the Pyretron system was $54.62/tonne
($49.61/ton). The incremental capital benefit from
improved capital utilization is the difference between
these two figures, $54.02/tonne ($49.12/ton).
B.2.2.2 Operating Costs and Benefits
The increase in throughput made possible using the
Pyretron system allows the quantity of waste treated
in the scenario to be completed in less time using the
same crew size. Specifically, the scenario assumed
that the conventional system was on the job site for
365 24-hour days, with 80 percent availability (20
percent downtime). The Pyretron system was
assumed to treat the same amount of waste in 183.4
24-hour days (with 80 percent availability).
The following tables illustrate the cost analyses
conducted. Table B-4 lists the cost assumptions for
the vendor's economic analysis. They are similar to
the assumptions made in Section 4 of this report
except that the vendor uses a higher capital cost,
interest rate and availability factor for the Pyretron.
B.2.3.3 Benefit Summary
The total incremental benefit for the Pyretron system
based on the incremental capital and operating costs
and benefits is $48.67/tonne ($44.26/ton). The
individual incremental costs and benefits are
summarized in Table B-5.
As the above analysis indicates, ACI's claim that the
Pyretron system is more economic to operate than
conventional rotary kiln incineration systems is
supported based on data supplied by ACI. In the
scenario examined in this analysis, approximately 68
percent of the cost savings can be attributed to
reduced operating costs.
A discussion of economics from EPA's perspective
based on high, low and average costs, was provided in
Section 4.
VENDOR EDITORIAL COMMENT. AT THE
REQUEST OF THE VENDOR, THE FOLLOWING
COMMENTS ARE REPEATED VERBATIM FROM
A MEMORANDUM FROM MARK ZWECKER
DATED MARCH 24,1989.
One of the most important subjects overlooked within
the EPA's analysis of the PYRETRON system in the
Technology Application Analysis, Section 6.5.2, is
risk assessment. This is a subject that regulators,
acting in the public's interest, must fully explore
when evaluating new technologies or applications of
equipment for handling toxic materials. ACI, while
not attempting to imply any corporate ability to
conduct risk analyses, offers the following summary
of how the Pyretron system will impact a typical
hazardous waste incinerator.
Risk Assessment
One of the most significant issues relating to
hazardous waste incineration is the potential risk to
the environment and population due to the release of
toxic contaminants from the activity. Release of
contaminants may occur due to stack discharge of
pollutants or due to a variety of other potential
fugitive emissions.
27
-------
Table B-4. Cost Evaluation Assumptions
Parameter
Conventional system
Pyretron system
Incinerator size (nominal total heat input)
Firing/feedrate (total heat input)
Propane heat input
Oxygen feedrate
Water feedrate
Waste feedrate
Base capital cost
Incremental capital cost
Royalty fee
Availability factor
Job duration
Common factors:
Quantity of waste treated
Heat content of waste
Auxiliary fuel and cost
Oxygen cost
Water cost
Crew
Crew cost
Equipment lifetime
Interest rate
12 MW (40 MMBtu/hr)
12 MW(40 MMBtu/hr)
7.41 MW (25.3 MMBtu/hr)
640 kg/hr (0.7 ton/hr)
$3,500,000
80 percent
365 24-hr days
4480 tonnes (4930 tons)
24.16 MJ/kg (10,410 Btu/lb)
Propane at $5.70/GJ ($6.00/MMBtu)
$0.088/sm3 ($2.50/MSCF)
$0.0008/L ($0.003/gal)
1 operator, 1 assistant, 2 material
handlers per shift, and 1 supervising
engineer day shift
$2401/24-hr day
15 years
n percent/yr
12 MW(40 MMBtu/hr)
15 MW (51 MMBtu/hr)
6.36 MW (21.7 MMBtu/hr)
1760 sm3/hr (62 MSCF/hr)
1820 L/hr (480 gal/hr)
1270 kg/hr (1.4 ton/hr)
$3,500,000
$100,000
$8.26/tonne ($7.50/ton)
80 percent
183 24-hr days
4480 tonnes (4930 tons)
24.16 MJ/kg (10,410 Btu/lb)
Propane at $5.70/GJ ($6.00/MMBtu)
$0.088/sm3 ($2.50/MSCF)
$0.0008/L ($0.003/gal)
1 operator, 1 assistant, 2 material
handlers per shift, and 1 supervising
engineer day shift
$2401/24-hr day
15 years :
11 percent/yr
Table B-5.
Summary of Incremental Savings and (Costs) for the
Pyretron System
$/tonne
$/ton
$/MMBtua
Capital cost and savings;
Initial ACI fee
Increase in capital utilization
Operating costs and savings:
Labor
Supplies
Propane
Oxygen
Water
Net supply savings
Other
Royalty
Total savings
(1.50)
54.03
97.28
90.86
(182.71)
(0.99)
(92.84)
(8.30)
$48.67/tonne
(1.40)
49.12
88.44
82.60
(166.10)
(0.90)
(84.40)
(7.50)
$44.26/ton
(0.07)
2.36
4.25
3.97
(7.98)
(0.04)
(4.05)
(0.36)
$2.13/MMBtu
$/KW are negligible so only $/Btu are shown.
28
-------
For this reason risk assessments are being more
consistently required by regulators before
incineration activities can be permitted. Risk
assessments are also being used more aggressively in
conjunction with the Right-to-Know regulations and
programs. A risk assessment includes four elements.
These elements are hazard identification, dose-
response assessment, exposure assessment, and risk
characterization. Any incineration activity should
have a risk assessment performed to determine the
potential worst case results of incinerating hazardous
components.
The PYRETRON TDS testing at the CRF has shown
some significant improvements for the incineration
of hazardous wastes. These improvements will also
translate into positive benefits in risk assessment.
When performing a risk assessment,the PYRETRON
system may directly reduce the risk associated with
hazardous waste incineration activities in three
ways;
1. The project duration time is reduced for a given
tonnage of waste material.
The PYRETRON system Transient Upset
Control System, specifically designed to respond
to prefailure conditions, reduce occurrence of
failure modes that result in harmful releases to
the atmosphere.
3. The PYRETRON system should more
consistently maintain a higher destruction
efficiency (DE) due to a reduction of the volume of
inerts entering the process.
These elements of improved control and increased
productivity combine to lower both the potential
emissions from the system and the human exposure
time. The net result is that even though a
conventional system may be able to attain acceptable
risk levels the PYRETRON system will reduce the
risks.
End of Vendor Editorial Comment
29
-------
-------
Appendix C
SITE Demonstration Results
This section summarizes the results of the SITE
demonstration of the Pyretron system as they
pertain to the evaluation of the developers claims. A
more detailed report on the demonstration is found
in the companion Technology Evaluation Report
which has been published previously (2).
The demonstration tests of the Pyretron Thermal
Destruction System were performed on a prototype
system retrofitted to the pilot-scale rotary kiln
incineration system at EPA's Combustion Research
Facility (CRF) in Jefferson, Arkansas. The
demonstration program began in November 1987
and was completed in January 1988. This program
was conducted using a mixture of 60 percent by
weight decanter tank tar sludge from coking
operations, RCRA listed waste K087, and 40 percent
soil excavated from the Stringfellow Superfund site
near Riverside, California. Table C-l summarizes
the POHC concentrations resulting from this waste
mixture.
Table C-1. POHC Concentration Estimates3
Naphthalene
Acenaphthylene
Fluorene
Phenanthrene
Anthracene
Fluoranthene
62 ħ 5.4t>
15 ħ 2.7
7.6 ħ 1.8
28 ħ 3.4
8.3 ħ 1.8
14 ħ 2.2
a(2)
b95 percent confidence interval.
The scope of the demonstration test program is
described in Section C.I. Section C.2 discusses test
program results.Test program conclusions are given
in Section C.3.
C.1 Demonstration Test Program
As noted above, the demonstration tests were
performed using a prototype Pyretron system
retrofitted to the rotary kiln incineration system
(RKS) at the CRF. A simplified schematic of this
system is given in Figure C-l.
The prototype Pyretron system retrofitted to the
CRF RKS was described in Appendix A. The
replacement burners were installed in the RKS in
the locations noted in Figure C-l as main burner and
afterburner.These burners were designed to fit
directly into the existing refractory penetrations for
the existing RKS burners.The gas (propane, air, and
O2) metering and control assembly was fabricated by
ACI, shipped to the CRF, and installed just outside
the building housing the incinerator. The trailer-
mounted C>2 tank with evaporator was supplied by
Big Three Industries.The ACI-supplied process
control computer system was installed in the CRF
control room, in parallel with the in-place RKS
control system.The ACI system controlled the burner
flows (propane, air, and O2).The existing RKS
control system controlled waste feed and scrubber
system operation.
For these tests, the fiber pack drum ram feeder
system was used to feed waste to the kiln.This
system feeds 5.7-L (1.5-gal) fiber pack drums in a
cyclical batch charge operation. Drums contained
between 4.1 and 7.9 kg (9 and 17 Ib) of waste
depending on the specific test underway.
Six tests were performed to supply data to evaluate
the ACI claims. Since the ACI claims state that the
Pyretron system offers superior performance when
compared to conventional incineration, one set of
operating conditions reflecting the limit of the
capabilities of conventional incineration in terms of
waste batch charge mass and total waste mass
feedrate was tested.
The capability limits for conventional incineration
were defined via several scoping tests.These tests
confirmed that a waste feed schedule of 10.9 kg (24
Ib) every 10 min resulted in unacceptable transients
in kiln exit flue gas CO levels.These transient CO
puffs survived passage through the afterburner and
gave unacceptable CO spikes at the stack. A waste
feed schedule of 9.5 kg (21 Ib) every 12 min resulted
in acceptable incinerator operation.This feed
schedule was defined to be the capability limit of
conventional incineration and was denoted the
optimum conventional operating condition. Two
31
-------
Afterburner Pyretron
burner
Propane -.yM_7
Aif Ğ:
Atmosphere
Venturi
inlet duct
Venturi
scrubber
Afterburner
50% caustic
f]
Solids
feeder
Main Pyretron
burner
Recirculation
pump
Carbon
adsorber
Cyclone >acked
separator tower
scrubber
Fresh
process
water
HEPA
filter
HEPA
filter
Stack
Recirculation
tank
To blowdown
collection
or disposal
Figure C-1. CRF rotary kiln system.
emissions tests (replicates) were performed at this
condition.
The other four tests were performed with the
Pyretron system in C>2 enhanced operation.The
optimum conventional operating condition was
repeated with the Pyretron system.Then a waste feed
schedule of 15.5 kg (34 Ib) every 19.5 min was tested
with the Pyretron system to evaluate the ACI claim
that the Pyretron system can reduce the magnitude
of transient puffs. Finally, a waste feed schedule of
9.5 kg (21 Ib) every 6 min was tested with the
Pyretron system to evaluate the ACI claim that
higher waste feedrates would be possible with the
Pyretron system. Two tests (replicates) were
performed at this last test condition as well.
Table C-2 summarizes the incinerator operating
conditions tested.
C.2 Demonstration Test Results
The results will be described in relation to the claims
American Combustion made about the performance
of the Pyretron.
As explained in Appendix B, American Combustion
contends that the Pyretron can significantly reduce
the magnitude of the transient emissions that occur
when solid waste is batch fed to a rotary kiln. The
demonstration results do not support that
contention. After a brief description of the tests that
pertain to the evaluation of transient emissions, an
explanation of why the results are inconclusive will
be given.
Since transients occur over a short period of time,
stripcharts from continuous emission monitors were
used to detect and record transients as they occurred
while the RKS being fed using various charge
mass/charge frequency combinations. Figure C-2
plots the variation in incinerator operating
parameters for the conventional incineration
attempt to feed 10.9 kg (24 Ib) of mixed waste every
10 min. The figure shows that, early in the test
period, kiln exit temperature varied from about 870
to 980°C (1,600 to 1,800°F) over a charge cycle.Kiln
exit O2 ranged from about 7 to 16 percent O2 over a
cycle, and kiln exit CO levels were generally low.
However, intermittent CO spikes up to 2,200 ppm
occurred. As this test proceeded, kiln temperature
increased such that, after about 3 hours of operation,
32
-------
CO
co
Table C-2. Average Incinerator Operating Conditions for the Tests Performed
Waste
Kiln exit
Afterburner exit
Test Operation
Conventional, scoping
1 Conventional, optimum
2 Conventional, optimum
replicate
3 Pyretron, at conventional
optimum
4 Pyretron, increase charge
mass
5 Pyretron, optimum
6 Pyretron, optimum replicate
Charge
weight,
kg (Ib)
10.9 (24)
9.5 (21)
9.5(21)
9.5(21)
15.5 (34)
9.5 (21)
9.5 (21)
Charge
interval,
minutes
10
12
12
12
19.5
6
6
Feedrate
kg/hr
(Ib/hr)
65.5 (144)
47.7 (105)
47.7(105)
47.7 (105)
47.7(105
95.5 (210)
95.5 (210)
Temperature
°C(°F)
1027 (1880)
954 (1750)
921 (1090)
1035 (1895)
963 (1765)
979(1795)
979 (1795)
Flue Gas
02
percent
9.9
13.3
12.8
17.6
14.5
13.9
14.6
Temperature
°C(°F)
1121 (2050)
1121 (2050)
1121 (2050)
1121 (2050)
1121 (2050)
1121 (2050)
1121 (2050)
Flue Gas
02
percent
6.4
7.7
7.4
15.2
15.0
14.0
15.3
-------
1,200
960-
800
3200 H
Q_ -52-
800-
0
15 -
70 -
0
270
90-
30
9 -
j L
1 0
T
Test
Start
T
12
T
14
T
M*ğJ
16
T
Test
Stop
18
Time of Day (hr)
Figure C-2. Kiln data for the conventional incineration scoping test: 65.6 kg/hr (10.9 kg every 10 min).
kiln exit temperature was ranging from 980 to over
1,150°C (1,800 to over 2,100°F) over a charge cycle.
Kiln exit flue gas 62 peaked at about 15 percent just
prior to initiating a. batch charge, but decreased to 0
as the puff of volatilized waste from a charge filled
the kiln. Kiln exit CO levels peaked at about 3,000
ppm under these depleted O% conditions. Figure C-3
shows that the CO puffs survived through the
afterburner and resulted in CO peaks of above 100
ppm at the stack.
In contrast, operating conditions for conventional
operation were much more controlled with a waste
feed schedule of 9.5 kg (21 Ib) every 12 min, as shown
in Figure C-4. At stabilized operation, kiln exit
temperature ranged from about 900 to 1,080°C (1,650
to 1,970°F) over a charge cycle. Kiln exit CO peaks
were less than about 50 ppm with the one exception,
a spike early in the test. These were reduced to less
than 10 ppm at the stack after passage through the
afterburner.
Figure C-5 shows the variation in operating
parameters for the Pyretron system test at an
increased charge mass of 15.5 kg fed every 19 min.
For this test, average kiln exit temperature was
comparable to the conventional incineration
optimum condition test at about 960°C (1,765°F),
though temperatures as low as 870°C (1,600°F) and
as high as 1,065°C (1,950°F) were routinely
experienced. Kiln exit flue gas O2 generally ranged
from about 13 to about 19 percent over a charge
cycle. However, kiln exit flue gas CO was generally
below lOppm. This test clearly established that a 60
percent increase in waste batch charge mass (9.5 to
15.5 kg) over the limit of conventional incineration
was possible with acceptable emissions transients
with the Pyretron system.
34
-------
Q.
o
o
(0
O
CD
O
o
350 -
200 -
50 -
0
16 -
10 -J
4 -
0
22.5 -
15 -
7.5 -
0 -
v^
I I .1, , 1 ...^ILJliliiJ
AA^vvvvv^A/v'v/\/v>/v^/^
II
*M
i i i i i j -T r 1
10 Test 12 14 16 Test 18
Start Stop
Time of Day (hr)
Figure C-3. Stack emission monitor data for the conventional incineration scoping test: 65.6 kg/hr (10k.9 every 10 min).
Figure C-6 shows the variation in operating
parameters for the Pyretron system test with a feed
schedule of 9.5 kg (21 Ib) every 6 min. This
represents double the feedrate achievable under
conventional operation. As shown in the figure,
average kiln exit temperature was about 980°C
(1,795°F) with routine variations from about 925°C
(1,700°F) to about 1,035°C (1,900°F). Kiln exit flue
gas O2 generally ranged from 11 to 17 percent. Kiln
exit flue gas CO peaks of about 100 to 300 ppm
occurred when kiln exit C>2 fell below about 10
percent. However, for other than these periods, CO
levels in the kiln exit flue gas were usually about 30
ppm. This test clearly shows that a waste feedrate
double that possible with conventional incineration
can be achieved with acceptable emission transients
with the Pyretron system. However, to achieve the
elevated feedrates demonstrated with the Pyretron
system, it was necessary to inject 136 L/hr (36 gal/hr)
of water into the incinerator to absorb the excess
heat released by the waste.
Transient emissions were to be evaluated by
comparing the frequency and level of transient CO
emissions as measured by continuous emission
monitors and recorded on stripcharts. Comparison of
the stripchart recordings of CO level for optimum
operation under the oxygen enhancement and air
only operation, Figures C-4 and C-6 show no obvious
visible difference between the frequency and
magnitude of transient CO emissions. As mentioned
earlier, an average of 16 transients/test were
observed during air-only operation. Only 6
transients/test were observed during oxygen-
enriched operation. Statistical analysis confirmed
that there were no statistically significant
differences between the frequency and level of
transient emissions that occurred between air-only
and oxygen-enhanced operation.(4) Further, these
figures indicate that transients do not occur as
frequently as one might expect given the high level
of organic content of the feedstream.These data
35
-------
, 1.200
5?
J-t- 900 H
800
3200 -
o
i aoo ~
0
""
log 15~l
70 ..
0
270 -
S 90 -
30
1
12
Test
Start
1
14
T
-T~
16
Test
Stop
18
Time of Day (hr)
Figure C-4. Kiln data for the optimum conventional incineration test: 47.7 kg/hr (9.5 kg every 12 min).
contrast with Figures C-2 and C-3 which show fairly
regular transients towards the end of the test.
There are several possible explanations for the
observed difference in transient emissions. Since
these were scoping tests, the conditions toward the
end were close to the stable operating limits of the
incinerator. It is conceivable that transients occur to
a significant extent only under suboptimal feeding
conditions and not under stable conditions. Since the
conditions that caused transients to occur under air-
only operation were different than those that caused
puffing under oxygen enhanced operation,
comparative data were not obtainable.
Another explanation for the irregularity in the onset
of transients lies in the nonuniformity of the waste
feed. Since the waste feed was a mixture of feed
streams that are not necessarily uniform to start
with, variations in the level and frequency of
transients might be due to variations in the level of
organic content in the feed stream over time.
The injection of water into the kiln during oxygen
enhanced operation may have altered the frequency
and level of transient emissions that would have
occurred with use of the Pyretron with oxygen
enhancement. This is plausible because the
formation of transient emissions is dependent upon
kiln temperature.(6,7) Water was injected into the
kiln to absorb heat and thus reduce temperatures.
The reduction in temperatures may have reduced
transient emissions during this mode of operation.
There may also be other reasons why transients did
not occur regularly. This result suggests that
transient performance is best evaluated in a more
controlled situation in which highly uniform
specially prepared waste streams can be fed. This
was, in fact, done at the U.S. EPA's Air and Energy
Engineering Research Laboratory in Research
36
-------
1,200
960 -
H 800
800 -
ħħ °-
uj ^ 200 -
0
15 -
(D & £
ill 70 -4
270 -
< * ^ 90 ^
30
g tr 9
0.0 C
rJ\^[^f\^f^\^^^
Instrument
Calibration
T
13 Test
Start
~T~
15
17
Test
Stop
Time of Day (hr)
Figure C-5. Kiln data for the Pyretron system test at increased charge mass: 47.7 kg/hr (15.5 kg every 19.5 min).
Triangle Park, North Carolina using a smaller
version of the Pyretron. That study will be discussed
more fully in Appendix D.
American Combustion also claims that the Pyretron
can achieve DREs greater that 99.99 percent at
elevated feedrates. This contention is supported by
the results of the demonstration. Even at feed rates
double those for conventional incineration,
incineration with the Pyretron was able to show
DREs in excess of the RCRA mandated 99.99
percent. Table C-3 summarizes the DREs achieved
for the POHCs in the mixed Stringfellow soil/K087
waste at a location in the flue gas that would
correspond to the stack discharge from a typical
industrial rotary kiln incinerator. This location is at
the packed tower scrubber discharge at the CRF.
None of the POHCs designated for these tests were
detected in the flue gas at this location. The DREs
noted in Table C-3 reflect method detection limits.
As shown in Table C-3, DREs at the scrubber
discharge were greater than 99.99 percent for many
POHCs. In many instances, detection limits allowed
establishing DREs greater than 99.9999 percent for
POHCs at higher waste feed concentrations. The
good DRE performance in all tests is understandable
since all tests were performed at relatively high kiln
and afterburner temperatures.
Particulate levels in the scrubber discharge flue gas
were in the 20 to 40 mg/dscm at 7 percent O2 range
regardless of test conditions. These levels were below
the incinerator performance standard of 180
mg/dscm at 7 percent O%.
The composite scrubber blowdown liquor and kiln
ash samples from each test were analyzed for the test
POHCs and other Method 8270 semivolatile organic
hazardous constituents and none were detected.
Since semivolatile organics were not detected in any
residual sample, firing mode (conventional versus
37
-------
S-i, 960-
o
o s^
s
800
aoo
0
70 -
0
270
90
30
O.
^*+Twrf\f>\*ĞA**K***W
-------
Table C-3. Scrubber Discharge POHC DREs
POHC ORE (percent)
Naphthalene Acenaphthylene Fluorene
Test 1 (12-9-87)
Train 1
Train 2
Test 2 (12-1 1-87)
Train 1
Train 2
Tests (12-17-87)
Test 4 (1-14-87)
Tests (1-20-88)
Train 1
Train 2
Test 6 (1 -21 -88)
Train 1
Train 2
> 99.99934 > 99.9975
> 99.99936 > 99.9976
> 99.99924 > 99.9967
> 99.9964 > 99.984
> 99.99896 > 99.9955
>99.99978 >99.99910
> 99.99989 > 99.99958
> 99.99990 > 99.99961
> 99.99991 > 99.99965
> 99.99990 > 99.99961
Table C-4. NOX Levels Observed
Test Date
12-08-87
1 12-09-78
2 12-11-87
8 1 -29-88
3 12-17-87
4 1-14-88
5 1-20-88
6 1-21-88
> 99.9945
> 99.9947
> 99.9933
> 99.968
> 99.9937
> 99.9981
> 99.9991 4
> 99.9991 9
> 99.99930
> 99.99923
During the SITE
Mode
Air
Air
Air
Air
02
02
02
02
Phenanthrene Anthracene
> 99.9985 > 99.9951
> 99.9986 > 99.9953
> 99.9984 > 99.9945
> 99.9920 > 99.974
> 99.9979 > 99.9933
> 99.99948 > 99.9983
> 99.99976 > 99.99922
> 99.99977 > 99.99927
> 99.99980 > 99.99935
> 99.99978 > 99.99929
Demonstration
Uncorrected
NOX Level ħ5%
101
80.6
117
67.9
1753
1064
750
725
Fluoranthene
> 99.9979
> 99.9980
> 99.9974
> 99.988
> 99.9960
> 99.9989
> 99.99949
> 99.99952
> 99.99953
> 99.99948
With respect to the second ACI claim, test results
clearly indicate that 99.99 percent POHC DRE was
achieved with the Pyretron system with waste
feedrate doubled over the limit established under
conventional operation provided that water is
injected when high heating value waste is treated.
Evaluation of the third ACI claim was discussed in
Section 4.
The high levels of NOX emissions observed indicate a
potential problem associated with using this
technology at sites where there are stringent
limitations on NOX emissions.This problem could be
alleviated through the use of a fully staged burner
design. ACI contends that the burner installed at the
CRF was not a fully staged design because the
burner penetrations on the CRF's rotary kiln were
too small.
39
-------
-------
Appendix D
Case Studies
D.1 Introduction
In this section two instances of the use of oxygen
enhanced incineration are described which support
results obtained during the SITE demonstration. The
first case describes studies conducted by the USEPA's
Air and Energy Engineering Research Laboratory
(AEERL) in Research Triangle Park, North Carolina.
In these studies a small-scale Pyretron was used to
study the effect of oxygen enhancement on the
reduction of transient emissions from the batch
charging of surrogate waste to a rotary kiln
simulator. The results of these studies underscore the
uncertainty regarding the ability of the Pyretron to
reduce transient emissions.
The second case involves the use of an oxygen burner,
different from the Pyretron, to burn dioxin
contaminated soil at an extended field demonstration
of the EPA's Mobile Incineration System at the
Denney Farm site near McDowell, Missouri. The
results of this case study illustrate how a well
planned application of oxygen enhanced incineration
can be very effective.
D.2 Pyretron Studies at AEERL
A small version of the Pyretron was installed on a 73
kW (250 kBTU/hr) Rotary Kiln Simulator at the
USEPA's AEERL to study the effect that oxygen
enrichment might have on the transient emissions
that occur when solid waste is batch fed to a rotary
kiln.(6) As mentioned earlier, transient emissions
occur when organic material that has been batch fed
to a rotary kiln suddenly volatilizes and momentarily
depletes the oxygen available in the kiln atmosphere.
This situation can result in the formation of toxic
pyrolysis products.
Three studies of transient formation were conducted
by AEERL. The first two were concerned with
determining the factors which influence transient
formation when solid and liquid wastes are batch fed
to the rotary kiln simulator. These studies did not
involve the use of oxygen enrichment. The third
involved determining the effect that oxygen
enrichment has on these emissions.
In the first study, the effects of charge mass, charge
area, and kiln temperature on transient formation
were determined through a series of experiments in
which plastic rods were incinerated in the kiln
simulator.(9) Four different types of plastic, Low
Density Polyethylene (LDPE), High Density
Polyethylene (HOPE), Polystyrene (PS),
Polyvinylchloride (PVC) in rods of different sizes
(surface areas) were treated in the kiln simulator at
two different temperatures and at 100 percent excess
air. Exhaust gas from the kiln simulator was
continuously monitored for Total Hydrocarbon
(THC), Carbon Monoxide (CO), Carbon Dioxide
(CO2), Oxygen (O2), and Nitrogen Oxides (NOX).
Peak height and peak area from the THC stripchart
recordings were used to measure the intensity and
magnitude of the transient emissions formed during
these experiments. The results of this study showed
that:
1. The four plastics studied showed different
transient behavior. While both LDPE and HOPE
rapidly formed transient gaseous products, PVC
released gaseous products much more slowly
during a transient episode. Both PVC and PS
require less oxygen for combustion than LDPE or
HOPE. This means that PVC and PS deplete the
kiln atmosphere of oxygen to a lesser extent than
LDPE or HOPE and therefore do not form
transient emissions as readily.
2. Regardless of the plastic studied, all formed
transients even though the experiments were all
conducted with the kiln simulator operating at
100 percent excess air.
3. Increases in temperature increased the rate at
which the transient emissions were produced, but
seemed to decrease the total amount of material
emitted during these transient episodes.
4. Toxic byproducts can be formed during
transients, especially when a mixture of
chlorinated and nonchlorinated wastes are being
batch charged to the incinerator.
In the second study, the effects of charge mass, charge
composition, kiln temperature and kiln rotation time
41
-------
were studied in the kiln simulator using a series of
liquid chemicals adsorbed onto ground corncobs.(7)
The chemicals studied were toluene, methylene
chloride, carbon tetrachloride and No.5 Fuel oil. Once
again the incinerator was operated at 100 percent
excess air and at two temperatures. Exhaust gas
monitoring was the same as in the study described
above. In addition, however, particulate emissions
were also sampled during each transient episode. The
conclusions drawn from this study are as follows.
1. Oxidation level in the kiln does not affect the
onset of transient emissions. They occurred even
though the kiln was operated at 100 percent
excess air.
2. Highly toxic byproducts, including dioxins and
furans can form during transients, especially
when mixtures of chemicals are fed (e.g. carbon
tetrachloride and toluene).
3. No single measurement accurately indicates the
onset of transient emissions for all feedstreams.
Carbon monoxide, THC peak height, THC peak
area, and particulate filter weight were all used
to detect and measure transients during this
study. Different measurements were good
measurements for different chemicals. Carbon
monoxide was a poor indicator for toluene
transients. Since toluene readily forms soot,
particulate filter weight was the best indicator.
For carbon tetrachloride, CO worked best.
4. Increases in temperature and kiln rotation speed
greatly increased the magnitude and intensity of
the transient emissions produced.
The third study involved installation of a small
version of the Pyretron on the rotary kiln simulator
in an effort to determine the effect of oxygen
enrichment on transient emissions.(6) Since these
emissions seem to be caused by the momentary
oxygen depletion of the kiln atmosphere, it was
thought that oxygen enrichment might reduce these
emissions. The kiln was fired as before and the
feedstream for the tests was toluene adsorbed onto
corncobs as in part of the previous test. All
measurements were identical to those conducted
previously. The studies conducted here attempted to
determine the effect of stoichiometric ratio, post
flame oxygen flow and post flame oxygen partial
pressure on the magnitude and intensity of the
transient emissions produced. While the effects of
post flame oxygen partial pressure and post flame
oxygen flow could not be directly determined, some
very important results were obtained. These include
the following.
1. While some reduction in transient emissions -~
possible with oxygen enrichment, the higher
temperatures that accompany the use of oxygen
is
ier
increase transient emissions far beyond any
reduction achieved. The net effect of the use of
oxygen is an increase in transient emissions.
2. The use of oxygen enriched combustion air leads
to very high NOX levels (as high as 1500 ppm).
3. The production of transient emissions in the kiln
probably cannot be prevented and so efforts must
be made to assure that these emissions are
eliminated in the afterburner.
D.3 Integration of These Results with
Those of the SITE Demonstration
The results of the SITE demonstration were
inconclusive with respect to the ability of the
Pyretron to reduce transient emissions. There are
three possible reasons why this is so. First, perhaps
the Pyretron did not reduce transient emissions. The
studies conducted at AEERL indicated that the
elevated temperatures that result from using oxygen
enrichment may increase transient emissions.(6)
Second, the waste used may not have been the type
that readily forms transient emissions. The organic
contaminants in the waste used during the SITE
demonstration were polycyclic semivolatile organic
compounds that perhaps did not volatilize as readily
as the volatile materials used in the AEERL study of
liquid wastes on sorbents.(T) This would mean that
they were less likely to volatilize and deplete the
oxygen in the kiln atmosphere when batch charged.
If the waste did not have a tendency to form
transients in the first place, it would be all the more
difficult to detect a difference in transient emissions.
Third, means may not have been available to
adequately detect transient emissions once they
formed. The AEERL studies indicated that four
different measurements, THC peak height, THC
peak area, CO level and particulate filter weight
needed to be used to adequately detect transient
emissions since no one measurement is adequate for
all wastes. Even though we attempted to measure
THC, we did not detect that many THC peaks.
Stripchart recordings of CO emissions provided the
only data available on transient emissions. The
AEERL studies indicated that CO was not always the
best indicator of transients, especially for those
compounds, like toluene, which tended to form soot
under oxygen deficient conditions. In those
situations, particulate filter weight was considered
the best measurement of transient emissions.(10)
The polycyclic aromatic hydrocarbons in the waste
used for the demonstration were structurally similar
to toluene and may be anticipated to form soot in
oxygen deficient conditions. Measuring particulate
filter weight might have been a better way to detect
and measure these emissions. Unfortunately, the
only EPA method approved for particulate
42
-------
measurement is EPA method 5. This method requires
measurement of the stack over a period of hours. This
is entirely too long since transient emissions occur
over a period of, at most, minutes.
For more information on these studies contact:
Dr. William P. Linak
U.S. EPA MD 65
Research Triangle Park, North Carolina 27711
(919)541-5792
DA The Use of an Oxygen Burner at
Denney Farm
This case study summarizes the use of an oxygen
burner on the EPA's Mobile Incineration System
(MIS) at an extended field demonstration at the
Denney Farm site near McDowell, Missouri.
Before proceeding, it is important to note that the
information presented in this section is preliminary
in nature. While the field demonstration at Denney
Farm has been ongoing for several years, the data
gathered during this period has not yet been analyzed
and formally reported on. Reports on this project
should be forthcoming soon, however, since the field
demonstration of the MIS will end in 1989.
Preliminary conclusions indicate that the use of this
burner on the MIS significantly improved the
efficiency of the cleanup effort at Denney Farm in
three ways. First, it may have helped to eliminate
several operational problems with the MIS. Second, it
may have helped to increase the hourly waste
throughput rate possible with the MIS. Third, as a
result of the first two improvements it significantly
reduced the cost of the cleanup at Denney Farm.
After a brief description of the MIS and of the burner,
the ways in which its use improved the efficiency of
the cleanup of the Denney Farm site will be discussed
in more detail. Finally, the relationship between
these results and the results obtained during the
SITE program will be discussed.
D.4.1 Description of the Mobile Incineration
System and Oxygen Enhanced Burner
Figure D-l is a block diagram of the MIS. The MIS is
a transportable incineration system consisting of a
2343 KW (8MMBTu/hr)rotary kiln, a secondary
combustion chamber allowing for 2 seconds residence
time, a cyclone, quench, wet electrostatic precipitator
and a scrubber. The cyclone is located between the
kiln and secondary combustion chamber and is
needed to remove soil particles which have been
entrained in the kiln atmosphere.
Since 1985, the MIS has been located at Denney
Farm burning soil contaminated with dioxin from
To Stack
Oxygen Burner Air Burner
Feed Ash|_ Ash
Figure D-1. Block diagram of MIS system.
Slowdown
eight sites in Southwest Missouri. Thus far 3.2
million kg (7 million Ib) of soil has been treated. (11)
The soil has a relatively low heating value of 465
kJ/kg(200BTU/lb).
From 1985 to 1986 the MIS successfully
decontaminated the dioxin bearing soil at a
throughput rate of 2000 Ib/hr. Unfortunately, the
fine particulate matter contained in the soil tended to
become entrained in the combustion gasses in the
kiln and subsequently settled out in the secondary
chamber. Enough material became entrained in the
combustion gas to build up to significant levels in the
SCC. This resulted in operational problems which
forced shutdowns every few days so that the
secondary chamber could be cleaned out.
During an extended period of downtime, several
modifications were made to the MIS in an effort to
increase both throughput and online time. During
this period an oxygen burner, was installed on the
rotary kiln of the MIS. A conventional air burner
continued to be used on the afterburner.
This burner is an oxygen burner that replaces all of
the combustion air with oxygen. By displacing
nitrogen in the combustion air stream, an oxygen
burner reduces the volume of combustion gas
required to incinerate solid waste. This can enable
more low BTU solid waste to be incinerated since
combustion gas volumes and, hence, velocities are
also reduced. Several design features included with
the burner are intended to alleviate operational
problems associated with oxygen enriched
combustion. Two design features are intended to
alleviate the high NOX emissions that often
accompany oxygen enhanced combustion. First, the
burner replaces all of the combustion air by oxygen.
The only air, and therefore nitrogen, that enters the
primary chamber, where the burner is mounted, is
air that leaks around the rotary kiln seals. By
limiting the amount of nitrogen available, the
amount of NOX that can form is also limited. Second,
the burner is designed to entrain combustion gasses
into the flame envelope. This is believed to reduce
flame temperatures. Since high flame temperatures
43
-------
increase NOS formation, reducing these
temperatures reduces NOX formation.
The burner was provided with a feedback process
controller which is designed to maintain a constant
oxygen level in the kiln based on oxygen readings
taken at the kiln exit. This design feature was
intended to help to reduce the transient emissions
that occur when solid waste is batch charged to a
rotary kiln.(12) A more detailed description of the
burner is provided elsewhere.(11)
It was hoped that by installing the burner with the
above mentioned design features, waste throughput
rates could be increased and operational problems
could be minimized. This would make the cleanup at
Denney Farm more efficient and less costly.
D.4.2 Throughput Increases
Use of the burner enabled the feedrate of soil to be
double from 2000 to 4000 Ib/hr. A successful trial
burn was conducted at this elevated feed rate and the
MIS permit was adjusted to allow for this increased
throughput.(ll)
D.4.3 Particulate Entrainment
While specific data concerning particulate carryover
are not available at this time, experience indicates
that particulate carryover was reduced after the
addition of the burner. A cyclone separator was
installed between the kiln and SCC at the same time
that the burner was installed, however, and this
modification may have been largely responsible for
reductions in particulate carryover. Nevertheless, it
is plausible that the installation of the burner helped
to reduce particulate carryover. This is because, as
mentioned earlier, the use of oxygen reduces
combustion gas volume, and velocity, by displacing
nitrogen. The linear velocity of the combustion gas at
the kiln exit was reduced from (calculated) 8 feet per
second to 3.3 feet per second.(ll) Less particulate
entrainment would be expected with reduced gas
velocity.
D.4.4 NOX Levels
Apparently, NOS levels did not increase much as a
result of the use of the burner. NOX levels are
continuously measured during the operation of the
MIS. Although all of this data has not been analyzed
yet, NOX levels recorded during the trial burn
conducted with the burner were between 54.6 and
138.3 ppm at 15 percent CO2. During an earlier trial
burn conducted before installation of the burner the
NOS levels were between 126 and 166 ppm at 11
percent CO2.U1) During a trial burn, air in-leakage
is minimized by preventative maintenance conducted
prior to the start of testing. On a routine basis, NOX
levels would be expected to be higher than those
recorded during a trial burn.
D.4.5 Transient Emissions
Like American Combustion, the manufacturer of this
burner also claims to reduce transient emissions
through use of their oxygen burner. Although
stripchart recordings of operational data exist for
both operation with and without the burner, these
data have not yet been analyzed to determine if there
is a statistically significant difference in the
frequency or level of transient emissions produced
with and without this burner. Even though it is
plausible to presume that maintaining a constant
oxygen level in the kiln through the use of a feedback
controller would reduce transient emissions caused
by momentary oxygen depletion, it is not possible to
draw any conclusions on this matter without the
above mentioned comparative analysis.
D.4.6 Economics
The economics of oxygen usage in this situation are
also favorable. The cleanup effort at Denney Farm
costs roughly the same whether or not waste is
processed. The increases in throughput and decreases
in downtime have reduced the estimated time on site.
As a result, savings from this reduction have more
than offset the added cost of the burner and oxygen.
D.5 Integration of These Results with
Those of the SITE Program
The use of oxygen on the MIS at Denney Farm was a
very effective application of this technology for three
reasons. First, the installation of oxygen was
intended to correct operational problems and not to
correct design flaws in the incinerator. Apparently,
installation of the burner did help to correct
operational problems that were increasing MIS
downtime.
Secondly, the waste which was to be treated included
low heating value wastes. Large increases in
throughput are possible for these wastes when
oxygen is used.
Thirdly, the situation in which oxygen was used was
a temporary situation which involved very high
operational expenses. Throughput increases and
increases in online time ultimately reduce the time
required for the cleanup and the unit cost for
processing waste. This significantly reduces
expenses. Thus, the expenses associated with the use
of oxygen are more than paid for by savings resulting
from reduced time on site.
44
-------
For more information on the use of the oxygen burner
at the MIS contact:
Joyce Perdek
US EPA
Releases Control Branch
Edison, NJ 08837
(201)906-6898
References for Appendices
1. Memorandum from Johannes Lee (Acurex
Corporation) to Laurel Staley dated March 14,
1989.
2. Technology Evaluation Report SITE Program
Demonstration Test, American Combustion
Pyretron Thermal Destruction System at the
U.S. EPA's Combustion Research Facility.
EPA/540/5-89/008 U.S. EPA, Cincinnati, Ohio.
March 1989.
3. Letter from M. Zwecker, American Combustion,
Inc., to A. McElligott, Acurex, dated September
19,1988.
4. Memorandum from Lisa Moore (EPA
statistician) to Laurel Staley dated June 2,
1988.
5. Staley, L. J., and R. E. Mournighan. "SITE
Program Update: The SITE Demonstration of
the American Combustion Pyretron Oxygen
Enhanced Burner." Journal of the Air & Waste
Management Association. Vol.39 No.2 p. 149
February 1989.
6. Linak, W. P, J. McSorley, J. Wendt and J. Dunn.
Rotary Kiln Incineration: The Effect of Oxygen
Enrichment on Formation of Transient Puffs
During Batch Introduction of Hazardous
Wastes. U.S. EPA, Research Triangle Park, NC.
December 1987. PB88140546.
7. Wendt, J. O. L., W. P. Linak, and J. A.
McSorley. Fundamental Mechanisms Governing
Transients from the Batch Incineration of Liquid
Wastes in Rotary Kilns. U.S. EPA, Research
Triangle Park, NC. March 1988. PB88177159.
8. Sample Calculations submitted to EPA by
American Combustion April 25, 1988.
9. Linak, W. P. J. D. Kilgroe, J. A. McSorley, J. O.
L. Wendt, and J. Dunne, "On the Occurrence of
Transient Puffs in a Rotary Kiln Incinerator
Simulator I. Prototype Solid Wastes" Journal of
the Air Pollution Control Association. V.37 N.I
January 1987 pp 54-65.
10. Linak, W. P., J. A. McSorley, J. O. L. Wendt,
and J. E. Dunn "On the Occurrence of Transient
Puffs in a Rotary Kiln Incinerator Simulator II.
Contained Liquid Wastes on Sorbent" Journal
of the Air Pollution Control Association V.37
N.8 August 1987 pp 934-942.
11. Ho, Min-Da, R. H. Sawyer, J. P. Stumbar, and J.
Perdek, "Long-Term Field Demonstration of the
Linde Oxygen Combustion System Installed on
the EPA Mobile Incinerator." presented at the
Fifteenth Annual Research Symposium on
Remedial Action, Treatment and Disposal of
Hazardous Waste in Cincinnati, Ohio April 10-
12,1989.
12. Interview with Frank Freestone, EPA MIS
Program Manager, USEPA March 28, 1989
(202)-3824515.
45
-------
-------
-------
Agency
Cincinnati OH 45268
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
Official Business
Penalty for Private Use, $300
Please make all necessary changes on the above label,
detach or copy, and return to the address in the upper
left-hand corner.
If you do not wish to receive these reports CHECK HERE D;
detach, or copy this cover, and return to the address in the
upper left-hand corner.
EPA/540/A5-89/008
------- |