EPA Report
RETROFIT COST RELATIONSHIPS
FOR HAZARDOUS WASTE INCINERATION
by
K. Lim, R. DeRosier, R. Larkin, and R. McCormick
Acurex Corporation
Energy & Environmental Division
Mountain View, California 94039
Contract 68-03-3043
Task SCA08
Project Officer
Dr. Benjamin L. Blaney
Incineration Research Branch
Industrial Environmental Research Laboratory
Cincinnati, Ohio 45268
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
v
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DISCLAIMER
The information in this document has been funded wholly by the United
States Environmental Protection Agency (EPA) under Contract 68-03-3043 to
Acurex Corporation, Energy & Environmental Division. It has been subject to
the Agency's peer and administrative review, and it has been approved for
publication as an EPA document.
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I
FOREWORD
When energy and material resources are extracted, processed, converted,
and used, the related pollutional impacts on our environment and even on our
health often require that new increasingly more efficient pollution control
methods be used. The Industrial Environmental Research Laboratory
Cincinnati (lERL-Ci) assists in developing and demonstrating new and improved
methodologies that will meet these needs both efficiently and economically.
This report provides information on the potential costs associated with
upgrading existing hazardous waste incineration facilities to comply with
RCRA performance standards. It is intended primarily for EPA utilization in
assessing cost/benefit trade-offs, although it may also be useful to other
individuals or organizations interested in hazardous waste incineration
economics. The Incineration Research Branch, lERL-Ci , may be contacted for
additional information on this subject.
David G. Stephan, Director
Industrial Environmental Research Laboratory
Cincinnati
in
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ABSTRACT
The U.S. Environmental Protection Agency is currently performing a
Regulatory Impact Analysis (RIA) of the RCRA performance standards for
hazardous waste incineration facilities. One of the key elements of this RIA
effort is the development of representative cost data for hazardous waste
incineration, including (1) capital costs for new facilities designed in
accordance with RCRA requirements, (2) operation and maintenance (O&M) costs
for these facilities, and (3) retrofit costs for existing facilities to
comply with RCRA standards. This report addresses the latter costs.
The objective of the study was to develop a methodology, and an
accompanying set of empirical cost relationships, that could be used to
estimate the costs of retrofitting/upgrading various components of existing
hazardous waste incineration facilities to comply with RCRA performance
requirements. Both the methodology and the retrofit cost relationships were
intended to focus on major capital additions or subsystem modifications that
could be required for RCRA compliance.
The results of the study are expressed in a series of empirical
relationships between the costs for various capital modifications/additions
and factors that significantly impact these costs, e.g., capacity, materials
of construction, etc. Costs are developed for (1) various aspects of
combustion system retrofit to improve destruction of toxic waste
constituents, (2) scrubbing system component addition, replacement, or
upgrading to improve particulate and/or HC1 removal, and (3) addition or
replacement of ancillary equipment mandated by combustion or scrubbing system
retrofit. The costs are based on a combination of in-house engineering and
vendor-supplied budgetary cost estimates.
Because the performance status of many existing incineration facilities
is unknown, particularly with respect to waste destruction efficiency in the
combustion process, it was not possible to predict within the framework of
this study what the actual retrofit requirements may be for the existing
incinerator population to comply with RCRA standards. Therefore, this study
was not designed to predict what the total retrofit costs would be for
industry as a whole. Rather, the results were intended only as a cost
estimating tool to aid EPA decision-making purposes.
This report is submitted in partial fulfillment of Contract
No. 68-03-3043 by Acurex Corporation, Energy & Environmental Division, under
the sponsorship of the U.S. Environmental Protection Agency. This report
covers the period June 1, 1982 to July 1, 1983, and work was completed as of
July 11, 1983.
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CONTENTS
Forward . ........... iii
Abstract iv
Figures vi
Tables vii
1. Introduction ........ 1
2. Incinerator Systems Considered 3
3. Engineering Economic Premises 6
3.1 Capital Costs 6
3.2 Comments on Retrofit Difficulty 7
3.3 Operation and Maintenance Costs 8
4. Combustion System Retrofit . 9
4.1 Burner Replacement ..... 10
4.2 Refractory Replacement 12
4.3 Combustion Chamber Replacement . 16
5. Quench/Waste Heat Boiler Addition 21
5.1 Quench Addition ........ . . 21
5.2 Waste Heat Boilers 24
5.3 Low-Temperature Quenches ...... 25
6. Scrubbing System Addition/Replacement/Modification . 29
6.1 Complete System Addition 30
6.2 Particulate Scrubbing System Addition/Replacement . . 33
6.3 Acid Gas Absorption System Addition/Replacement/
Modification 37
7. Flue Gas Handling Equipment 40
7.1 Induced Draft Fan Addition/Replacement 40
7.2 Stack Replacement . 45
8. Total Incineration System Replacement 50
8.1 Description and Purpose of Replacement . 50
8.2 Applicability and Limitations 51
8.3 Assumptions and User Guidelines 51
8.4 Costs 51
9. Downtime Considerations ........... 56
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FIGURES
Number Page
1 Generalized flow diagram for quench/scrubber system 4
2 Purchase cost of new burners (July 1982) 11
3 Purchase cost of multiple-chamber, hearth incinerators
(July 1982) 18
4 Purchase cost of rotary kiln incinerators (May 1982) 19
5 Purchase cost of liquid injection incinerators
(July 1982) 20
6 Purchase cost of quench towers (July 1982) 23
7 Purchase cost of waste heat boilers (July 1982) 26
8 Purchase cost of low-temperature quenches (July 1982) 28
9 Purchase cost of scrubbing systems receiving
1,800° to 2,200°F gas (July 1982) 32
10 Purchase cost of scrubbing systems receiving
500° to 550°F gas (July 1982) 34
11 Purchase cost of carbon steel fans (July 1982) 43
12 Purchase cost of corrosion-resistant fans (July 1982) 44
13 Fabricated cost of FRP stacks (July 1982) 48
14 Fabricated cost of refractory-lined steel stacks
(July 1982) . 49
15 Purchase cost of complete liquid injection incineration
systems (July 1982) 52
16 Purchase cost of complete multiple-chamber, hearth
incineration systems (July 1982) 53
17 Purchase cost of complete rotary kiln incineration
systems (May 1982) 54
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TABLES
Number
1 Estimated cost of refractory (July 1982) 15
2 Scrubbing/flue gas handling system component
cost breakdown 31
3 Pressure dorp versus outlet particulate loading and
collection efficiency . 37
4 Estimated installation times for incinerator
system components . ...... 57
5 Baseline hazardous waste incineration costs . . 59
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SECTION 1
INTRODUCTION
Under the Resource Conservation and Recovery Act (RCRA), the U.S.
Environmental Protection Agency is required to establish a federal hazardous
waste management system, including standards for hazardous waste incineration
facilities. As part of that effort, the EPA Office of Solid Waste is
currently executing a Regulatory Impact Analysis (RIA) of performance
standards for hazardous waste incinerators (HWI). The RIA is intended to
help determine the costs and benefits of various regulatory standards. This
study provides background information for the RIA by addressing the cost of
retrofitting existing hazardous waste incinerators to improve performance and
limit exhaust emissions.
The objective of this report is to provide retrofit cost relationships
for modifications or additions to existing hazardous waste incineration
systems. "Incineration system" refers to all the equipment necessary to burn
hazardous waste in compliance with regulatory requirements. Thus, an
incinerator system includes the waste handling and feed system, the
incinerator itself with associated ash-handling equipment, downstream air
pollution control devices (APCD's) such as scrubbers and absorbers, flue gas
handling equipment, and exhaust stack.
This report provides a methodology for estimating the costs of
retrofitting various components of an existing HWI system for the purposes
of:
Increasing removal efficiency of principle organic hazardous
constituents (POHC)
Reducing particulate loading to <0.08 gr/dscf
Reducing HC1 in flue gas by 99 percent for wastes containing
>0.5 percent chlorine
Some existing HWI systems may require no modifications to meet proposed
standards. Other systems may require extensive, multiple component
modifications. For still others, retrofit may not be feasible because of
economic, space, or equipment design limitations. Thus, caution should be
exercised in applying the retrofit cost estimates provided in this report to
a specific situation.
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Retrofit costs include the installed cost of new equipment for the
existing incinerator system, any incremental operation and maintenance costs
over and above those of the original system, and downtime costs associated
with system retrofit. This study focuses on the major cost factor: capital
costs for new equipment.
The study excludes minor equipment modifications/additions. For
example, burner and refractory replacement costs for an existing incinerator
are quantified, but minor changes such as burner/air register adjustments
fall under the category of "fine-tuning." Fine tuning costs are generally
minor compared to the cost of major capital modifications/additions and they
are very facility specific. This study also excludes the costs of trial
burns and other permitting requirements (for both construction and operation)
associated with facility retrofitting because these costs are highly
case-specific. Estimates of trial burn and other permitting costs for new
facilities are presented in Section 4 of Reference 1.
The approach taken here relies heavily on contacting major equipment
vendors and reviewing their experience in HWI retrofits. Engineering
estimates were used to augment the collected data, especially material
requirements and installation costs. Because the study assumed a wide range
of waste characteristics and various incinerator system designs and
configurations, a detailed engineering study was not possible. Rather,
budgetary engineering estimates, based on vendor data, were made. For
budgetary purposes, the equipment costs should be accurate to within
±30 percent. Larger uncertainties are associated with installation costs, as
discussed in subsequent sections.
This retrofit cost study was performed in conjuction with a larger-scale
project to estimate capital and operation/maintenance (O&M) costs for new
hazardous waste incineration facilities designed in accordance with RCRA
performance standards. The results of this larger-scale study are presented
in a report entitled, "Capital and O&M Cost Relationships for Hazardous Waste
Incineration" (Reference 1). The results of the retrofit cost study overlap
to some degree with the results presented in Reference 1. In cases where
this overlap occurs, only the major assumptions and bottom-line cost
estimating relationships are presented herein. The reader should refer to
Reference 1 for detailed derivations and background information.
The next section of this report reviews the incinerator systems
considered. Section 3 presents the engineering economic premises. Section 4
through 8 provide retrofit cost relationships for various incineration system
components. Section 9 concludes with a brief discussion of downtime
considerations. The format of this report is user oriented. Cost
relationships are provided, but the actual application of these functional
relationships is left to the user of this report.
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SECTION 2
INCINERATOR SYSTEMS CONSIDERED
The hazardous waste incineration designs and capacity ranges addressed
in this study are as follows:
Liquid injection (1 to 100 million Btu/hr)
Rotary kiln (1 to 100 million Btu/hr)
Multiple chamber, hearth (1 to 50 million Btu/hr)
Design temperature ranges are assumed to be 1,500° to 1,800°F for kilns and
hearth incinerator primary chambers, and 1,800° to 2,400°F for kiln/hearth
incinerator afterburners and liquid injection furnaces.
The hazardous wastes burned in these incinerators are assumed to be
hydrocarbon or aqueous based with heating values ranging from essentially
0 to 15,000 Btu/lb, and moisture levels of 0 to 90 percent. It is assumed
that chlorine is the only halogen present. Ash and salts may also be present
in variable amounts.
Uncontrolled particulate emissions from burning these wastes are assumed
to range up to 2.0 gr/dscf, and flue gas chlorine (HC1) concentrations may
range from 0 to a maximum of 2 percent by volume. For the purposes of this
study (and in Reference 1), venturi scrubbers are assumed for particulate
control and packed tower absorbers are assumed for HC1 removal. The
generalized air pollution control system is shown in Figure 1. As indicated
in this schematic, a water quench is installed upstream from the scrubbers to
reduce gas temperature to <200°F, and an ID fan and stack are installed
downstream. Inclusion of a waste heat boiler upstream from the quench is
optional. For more detailed information on air pollution control system
design, or incinerator design, the user should refer to Sections 2 through 4
of Reference 1.
The hazardous waste incineration system upgrade goals addressed in this
study are to:
Increase removal efficiency of principle organic hazardous
constituents (POHC)
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To
atmosphere
-1
ID Fan
Caustic solution
Slowdown
to disposal
Figure 1. Generalized flow diagram for quench/scrubber system.
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Reduce participate loading to £0.08 gr/dscf
Reduce HCl in flue gas by 99 percent for wastes containing
>0.5 percent chlorine
Because the correlation of POHC removal efficiency with combustion conditions
is not -well established, quantification of the specific combustion system
upgrade requirements is not possible. Therefore, this study only estimates
the typical costs associated with hardware modifications that may be
implemented to improve combustion efficiency, raise combustion temperatures,
and increase residence times at peak temperatures. Rigorous correlation of
POHC removal efficiency with costs is not possible at this time.
The specific HWI retrofit modifications/additions considered for
improving incinerator efficiency and minimizing exhaust emissions are:
Combustion system retrofit
Burner replacement
Refractory replacement
Combustion chamber replacement
Quench addition
Waste heat boiler addition
Scrubbing system addition/replacement/modification
-- Venturi scrubber replacement
Acid gas absorber addition/replacement/modification
Complete system retrofit
Flue gas handling equipment addition/replacement
-- Fan and motor
Stack
Total incineraton system replacement
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SECTION 3
ENGINEERING ECONOMIC PREMISES
This study considers the retrofit or modification of components of an
existing hazardous waste incineration system with ready access to equipment;
i.e., there is no extreme congestion at the site. The equipment layout
scheme is assumed to have no unusual configurations or complex ductwork due
to space limitations. This is usually a good assumption because hazardous
waste incinerators are generally located in open space, away from congested
urban areas. Even a dedicated incineration facility which serves a process
chemical plant is rarely located in the middle of the congested plant but
rather at its periphery. If, however, site congestion is a problem, retrofit
costs will increase accordingly, due primarily to increased installation
costs and other site-related and field work.
3.1 CAPITAL COSTS
Total capital costs for retrofitting are given by the sum of the direct
and indirect costs, plus contingency costs. Direct costs are the sum of the
fabricated equipment costs, freight, and installation.
The equipment cost includes necessary instrumentation and controls where
appropriate. Installation costs include foundations and supports, ductwork,
piping, insulation, electrical, and all necessary labor. In this study,
installation cost is usually specified as a percentage of the purchased
equipment cost. A range is generally specified to account for variations in
retrofit difficulty.
Indirect costs associated with the retrofit must be added to the
installed equipment cost (direct cost). Indirect costs include:
Engineering (10 percent of direct costs)
Construction field expense (10 percent of direct costs)
Construction fee (8 percent of direct costs)
Startup (2 percent of direct costs)
The owner of the incinerator or an engineering contractor must perform an
engineering feasibility study on the merits of retrofitting equipment to
upgrade incinerator and/or air pollution control equipment performance. If
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a go ahead decision is made, then bid specifications and vendor bid reviews
must be completed. An engineering study is also required to integrate the
new or upgraded component(s) to ensure system compatibility.
Construction field expenses include the cost of scaffolding, service,
and utility facilities and other remote support. A general contractor is
required to coordinate all construction activities.
Startup costs are estimated to be 2 percent of direct costs. Unlike a
completely new facility, the contractor only needs to be directly concerned
with the particular component(s) being modified or retrofitted. All other
components of the incineration system are assumed to be operational. There
is less downtime associated with waiting for other components to be
"de-bugged" and operator training is usually minimal.
Finally, a contingency of 15 percent of direct plus indirect costs
should be added to obtain the total cost.
3.2 COMMENTS ON RETROFIT DIFFICULTY
Costs of extensive retrofitting can be higher than those for a new
installation, due primarily to installation costs and site-related indirect
costs. Examples of increased retrofit difficulty factors include:
Service relocations (e.g., pipe racks, wiring, access roads)
Convenience of staging area (proximity of staging area to
installation site)
Difficulty of rigging (site constraints which hinder use of high
lift equipment)
Operating interferences (construction which requires an
incinerator shutdown)
Structural relocation (building space layout considerations)
Foundation site preparation (dependent on terrain and site
geology)
Long duct runs and bypasses
Elevated structures
Existing equipment limitations (e.g., obsolescence, internal space
constraints)
The above difficulties are due mainly to space limitations, and can only be
evaluated on a site-specific basis. If space limitations are not a problem,
then potentially, retrofit costs could be as low as "grass roots" costs. On
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the other extreme, space limitations and/or equipment constraints could make
retrofit impractical altogether.
3.3 OPERATION AND MAINTENANCE COSTS
In general, additional operation and maintenance (O&M) costs can be
expected with retrofitted components in an existing hazardous waste
incinerator system. The associated O&M costs of the modified facility should
be calculated as specified in Reference 1. Then, the difference in system
O&M costs before and after retrofit can be identified. This cost difference
can then be attributed to the overall cost of upgrading an existing
incineration system. In the following sections on component equipment costs,
significant O&M cost differences are noted where appropriate.
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SECTION 4
COMBUSTION SYSTEM RETROFIT
A number of potential combustion system modifications can be considered
for upgrading the performance of an existing hazardous waste incinerator
(HWI). Incinerator performance (e.g., POHC destruction efficiency) can
potentially be upgraded by increasing combustion chamber temperature above
the original design specification and/or increasing effective residence time
at peak temperature. Combustion system modifications that have the potential
to achieve these improvements include:
Adjusting burner/air registers for higher combustion efficiency
Replacing kiln seals to reduce air infiltration
Modifying solids feed systems to minimize air infiltration
Replacing existing burners with new higher efficiency, lower excess
air design burners to achieve more rapid mixing, higher mean
temperature, and longer times at peak temperature
Replacing existing refractory to accommodate higher temperature
operation
Replacing the combustion chamber with a new unit designed for higher
temperature and/or longer residence time operation
The first three modifications listed above are essentially fine tuning
adjustments for achieving more efficient operation of a hazardous waste
incinerator. The actual hardware changes and/or operational changes involved
are variable from HWI facility to facility. Furthermore, because they are
generally simple modifications of relatively low cost, they will not be
treated further in this study.
This section focuses on the major modifications of burner, refractory,
and combustion chamber retrofit.
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4.1 BURNER REPLACEMENT
4.1.1 Description and Purpose of Retrofit
A complete burner system includes the burner itself plus valve train,
blower and damper assemblies, flame safeguards, and controls. In addition to
introducing high-Btu wastes, burners may be used to introduce secondary fuels
(either supplementary fuel to augment combustion or low heating value wastes
which must be injected peripherally). Alternatively, separate burners may be
used for supplemental fuel firing.
In rotary kiln, hearth, and liquid injection incinerators, the burner
design and placement affect the amount of excess air required as well as
influence fuel/waste/air mixing and combustion efficiency. Burner designs
have advanced sufficiently in recent years that a new burner may achieve
higher efficiency with more rapid mixing and higher temperatures than many of
the older burners currently operating in the field. Thus a new burner(s) may
be retrofitted to improve combustion efficiency, accommodate a waste
different from the one originally designed for, or to introduce supplemental
fuel.
4.1.2 Applicability and Limitations
Increasing incinerator efficiency through burner replacement is
potentially applicable to all incineration systems in which the waste is
introduced via burners, rather than by lances. Of course, the combustion
chamber must be able to accommodate the flame envelope and zonal heat release
rate of the new burners, as well as being physically compatible with the new
burner assembly. Such determinations must be done on a case-by-case basis.
4.1.3 Assumptions and User Guidelines
The retrofit burner costs developed here assume the following:
The entire burner system, not just the nozzle, is replaced
Burners are sized similar to dual-fuel burners firing residual oil
and natural gas
Off-the-shelf, rather than custom burners, are available and
applicable. This assumption is qualified below as a "best case"
scenario for baseline cost estimating purposes.
The actual improvement in combustion efficiency and resultant increased
temperature and/or residence time must be determined on a site-specific
basis.
4.1.4 Costs
Figure 2 presents purchased equipment cost as a function of burner
capacity. These costs include blowers, dampers, flame safeguards, and
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o
o
o
o
u
(X
70
60
50
40
30
20
10
10 20 30 40 50 60 70
Burner capacity (million Btu/hr)
80
90
100
Figure 2. Purchase cost of new burners (July 1982).
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combustion controls. Retrofit installation cost is roughly 50 percent of the
purchased cost. The costs presented are from one vendor, based on a
dual-fuel burner with half of the nominal heat input capacity coming from
natural gas. It should be noted that many vendors prefer to custom fabricate
burners for the specific fuel and facility. Due to the inherent
site-specific nature of this design methodology, prices for these custom
burners will be higher than stock designs. Thus, it is not possible at this
time to produce a generalized cost for custom burners. The costs presented
here for standard burners should be considered as baseline, minimum costs if
new burners were to be retrofitted in an existing HWI.
To obtain the total retrofit cost, indirect costs such as engineering
and construction field expenses and contingency costs must be added to the
installed equipment cost, as specified in Section 3.
No additional operation and maintenance considerations are required
beyond those specified in Reference 1. If supplementary fuel is required,
the additional fuel costs are calculated as in Reference 1.
4.2 REFRACTORY REPLACEMENT
4.2.1 Description and Purpose of Retrofit
The combustion chambers of incinerators are lined with refractory,
nonmetallic insulating materials resistant to high temperatures. Refractory
for incinerators is ordered by the type and thickness required, depending on
the environment (thermal cycling, temperatures, abrasion, erosion, presence
of acid/alkali) expected. Refractories may be in brick or castable form, and
are often priced in terms of brick equivalents (one brick is 9 in.
by 4-1/2 in. by 3 in.).
Replacing the existing refractory with a higher grade material is a
means of accommodating higher incinerator temperature operation to promote
POHC destruction. Methods to estimate costs for refractory replacement are
presented below.
4.2.2 Applicability and Limitations
Refractory is routinely replaced (e.g., every 1 to 5 yr, depending on
service conditions) due to the wear associated with normal operation. Thus,
refractory upgrade/replacement is an option for incinerators for which the
existing refractory is inadequate to handle the desired higher operating
temperature. However, the changes required to handle new operating
conditions must not be so extensive as to make combustion chamber replacement
necessary. For example, increasing the temperature increases the gas volume
which reduces residence time. High temperatures may also necessitate thicker
refractory, which reduces the chamber volume, thereby also reducing the
residence time. Both of these factors may reduce residence time below what
is necessary for waste destruction.
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4.2.3 Assumptions and User Guidelines
Refractory replacement costs are based on the following incinerator
design assumptions:
Nominal heat release rates are 30,000 Btu/hr-ft^ for liquid waste
incinerators and rotary kilns and 15,000 Btu/hr-ft3 for hearth
primary chambers
Liquid waste incinerators and afterburners are cylindrical with
length-to-internal diameters of 3:1
Rotary kiln incinerators have length-to-internal diameter ratios of
2:1
Hearth incinerator primary chambers are rectangular with
length:width:height ratios of 2:1:1
Afterburner residence times are nominally 2 sec at design exit gas
temperature
4.2.4 Costs
--^ Refractory replacement costs include removal, installation, and material
^, costs. Refractory material requirements and costs are first estimated.
The volume of refractory required can be estimated as follows:
Rotary kiln (walls and feed plate):
Vr = 2* h DI (h + 1.125 DT)
Q /3
.
1 yl5,000rr I
Liquid injection incinerator:
Vr = 3n h Di (h + 1.167 D-j )
withDi=/ *r V/3
1 I 22,500ir I
Afterburner:
Vr = 3«r h Of (h + 1.167 Dj)
withD.
1 ll,700ir
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Hearth primary chamber:
V >°
with W1 =
QT V/3
30,000,
where
= refractory volume (ft3)
= thickness of refractory (ft)
= inside diameter of incinerator (ft)
= maximum firing rate of incinerator (Btu/hr)
= total gas flow out of incinerator (scfm)
= temperature in afterburner (°F)
W-j = internal width of hearth primary chamber (ft)
The total gas flow, qyg, is calculated as in Section 3.4 of Reference 1.
Typical afterburner temperatures range from 1,800° to 2,400°F. The thickness
of refractory required is typically 9 in. for all incinerators and
temperatures expected here, although a range of 6 in. (two bricks) to
13-1/2 in. (one brick plus 9 in. of insulating firebrick) exists depending on
the application and vendor. For some applications involving relatively light
service, castable refractory may be used because of ease of repair and
economy. Although the actual thickness used will vary as much as with brick,
a thickness of 6 in. should be adequate since castable is a better insulator
than brick.
Based on a 9 in. by 4-1/2 in. by 3 in. brick, one cubic foot contains
14.2 brick equivalents. The cost of the brick depends on the application,
although the general range is from $.80/brick to $3.00/brick. Exotic bricks
used for high temperature and severe environments may cost well over
$10.00/brick.
Although many properties of a given refractory must be taken into
account before choosing the best refractory for a specific application, the
initial criterion is the alumina-content. Generally, the high alumina
refractories cost more and will withstand high temperatures better than low
alumina refractories. For low temperatures of 1,400° to 1,800°F, a brick
composed of approximately 45 percent alumina is appropriate. A 60 percent
alumina refractory is appropriate for temperatures up to approximately
2,400°F, and a 90 percent alumina refractory would be used for temperatures
above 2,600°F, although such high alumina is approaching the exotic
classification. Resistance to'acid, alkali, erosion, and thermal shock are
incorporated in refractories to various degrees of design compromise,
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depending on the application. However, refractory prices reflect the
severity of the various chemical and physical demands imposed by the
environment in which it will be used.
Table 1 presents some representative prices for refractory bricks in
potential applications. These are based on vendor estimates. Mortar should
also be included in the price of materials, assuming 315 lb/1,000 brick
equivalents and an approximate cost of $600/ton. This amounts to an
additional $Q.10/brick. Although some incinerator manufacturers prefer to
use castable refractory, castables have been costed only for application
without chlorine, alkali, or other waste components which attack the
castable bonding material. The castable is costed for the hydrocarbon cases
for the liquid injection incinerator where it doesn't have to withstand
chemical attack. The prices in Table 1 were selected as representative of a
durable refractory in common use. Depending upon the specific application
(waste characteristics, incinerator design, cycling duty, severity of
service, etc.), refractory material costs could vary by a factor of 2.
Replacement costs for all the refractory in an incinerator (not just
patching) is composed of removal, installation, and material costs. Removal
costs are roughly equal to installation costs, while installation costs range
from 1 to 4 times the materials cost, depending on the cost of the materials
and the difficulties associated with installation in a particular facility,
such as access to the combustion chamber. Therefore, total installed
replacement costs (material, installation, and removal of previous material)
will range from 3 to 9 times the cost of the material. A representative
total installed cost is 5 times the material cost.
TABLE 1. ESTIMATED COST OF REFRACTORY (DOLLARS PER BRICK)a (JULY 1982)
Temperature
1,400° to 1,800° to 2,200° to
Incinerator Waste 1,800°F 2,200°F 2,600°F
Liquid injection Hydrocarbons 1.60 1.60 1.60
or afterburner
Hydrocarbons plus 1.80 2.60 2.60
chlorine and/or
alkali
Rotary kiln or All 2.60 2.60 2.60
hearth
aA brick equivalent is 9 in. by 4-1/2 in. by 3 in.
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4.3 COMBUSTION CHAMBER REPLACEMENT
4.3.1 Description and Purpose of Retrofit
The combustion chamber is the heart of rotary kiln, liquid injection,
and hearth incineration systems. It consists of a shell, burners,
refractory, combustion controls, and blowers. The combustion chamber
excludes the feed system, pollution control devices, and quenches. Within
the scope of this study, combustion chambers are assumed to be retrofitted to
a facility only if the increased performance demands cannot be met by
modification of the existing unit, due to physical or space constraints. For
example, increasing the operating temperature substantially would necessitate
replacing the refractory with a thicker lining of more expensive brick.
This, in turn, reduces the internal volume of the incinerator, and combined
with the increased temperature, reduces the effective residence time such
that a complete, new combustion chamber may be required.
4.3.2 Applicability and Limitations
Combustion chamber replacement is, in principle, potentially applicable
to all incinerator designs. Specific limitations can only be ascertained on
a specific incinerator design and site location basis.
4.3.3 Assumptions and User Guidelines
In estimating combustion chamber retrofit costs, the following design
criteria are assumed:
Liquid injection incinerators are designed to accommodate operating
temperatures up to 2,200° to 2,400°F. Nominal residence time is
2 sec. The refractory lining is 6 to 8 in. of >3,000°F castable or
60 to 80 percent alumina firebrick (backed by insulating castable),
which is suitable to withstand corrosive environments. Separate
air-atomized guns and valve trains are provided for fuel, high- and
low-Btu wastes. Combustion air blowers and accessories, complete
flame safeguard and combustion control instrumentation are also
included.
Rotary kiln incinerators are designed for 1,500° to 1,800°F
operation in the kiln and up to 2,400°F operation in the
afterburner. Nominal gas residence time is 2 sec. The kiln itself
consists of a stainless steel shell with dual girth gears, trunnion
roll, and drive assemblies. The primary refractory lining is
70 percent alumina, 9 in. thick in the kiln and afterburner. The
afterburner is horizontally aligned and integrally connected to the
kiln breeching. Accessory equipment includes an ash quench tank and
conveyor, ram feeder for bulk solid wastes, feed chute and double
air-lock assembly for drum feeding in large units, high-Btu
waste/fuel burners in the kiln and afterburner, low-Btu waste guns
and slurry lances in the kiln feed plate, combustion air blowers,
and a complete instrumentation package.
16
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Hearth incinerators are two-chamber units designed for 1,400° to
1,800°F operation in the primary chamber, 1,800° to 2,000°F
operation in the secondary chamber, and 1 to 2 sec retention time in
the secondary chamber, depending on capacity. Refractory is 3,000°F
rated castable. Accessories include a ram feeder for solids,
waste/fuel burners in the primary and/or secondary chambers (startup
burners in both), an air blower, and control instrumentation. An
ash ram, ash quench tank, and ash conveyor are also included in.
>10 million Btu/hr units.
4.3.4 Costs
Figures 3 through 5 present purchased equipment cost as function of
incinerator capacity for hearth, rotary kiln, and liquid injection
incinerators, respectively. Of course, the type of waste burned will have
some effect on the cost, since it influences burner design, residence time,
and temperature requirements. However, these estimates are based on
reasonably conservative design criteria, and should be acceptable within the
limits of budget pricing.
The cost of installing a new combustion chamber ranges from 25 to
100 percent of the purchased equipment cost. Typically a new installation
will cost between 35 and 50 percent of the purchased equipment cost depending
on size, degree of prepackaging, and other such considerations. A retrofit
installation cost will approach the upper end of this range because the old
unit must be removed. Freight charges of 5 to 10 percent of the purchased
equipment cost should also be included in the total installed equipment
cost.
To obtain the total capital cost, indirect costs such as engineering and
construction field expenses and contingency costs must be added to the
installed equipment cost, as specified in Section 3.
17
-------
1,000
600
400
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Figure 5. Purchase cost of liquid injection incinerators (July 1982)
20
-------
c
SECTION 5
QUENCH/WASTE HEAT BOILER ADDITION
If air pollution control devices such as venturi scrubbers or acid gas
absorbers are added to an existing incineration system, some means of cooling
the hot flue gas prior to entry into the air pollution control devices (APCD)
must be provided. Alternative cooling methods include a water quench or a
waste heat boiler followed by a low-temperature quench. Energy recovery
through a waste heat boiler may be preferred if the specific application is
cost effective.
Quench replacement could also be required under circumstances where the
incinerator is upgraded to operate at a substantially higher temperature. In
many such cases, however, the existing quench may only require modification
rather than replacement. Additional spray nozzles providing more cooling
capacity can be added at a relatively low cost compared to complete quench
system replacement. The costs for spray nozzle addition are not treated here
because they are relatively minor compared to the costs associated with the
major modifications and additions considered in this study.
5.1 QUENCH ADDITION
5.1.1 Description and Purpose of Retrofit
Quenches are used to reduce the temperature of the incinerator exit gas
from 1,800° to 2,400°F down to adiabatic saturation temperature to protect the
air pollution control system. Several quench designs are suitable for this
purpose, including spray towers; submerged exhaust, pot-type quenches; and
in-line, high-pressure spray quenches utilized with wetted throat venturi
scrubbers. Quenches are frequently supplied by scrubbing equipment vendors as
part of the overall gas cleaning/flue gas handling system. This retrofit
scenario, in which an entire quench/scrubbing/flue gas handling system is
added to the facility, is addressed in Section 6.
In some situations, however, it may be necessary to replace only the
quench. In other cases, the scrubbing system may be purchased component by
component from different vendors rather than from a single turnkey contractor.
These are the scenarios addressed in this section.
21
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5.1.2 Applicability and Limitations
The costs presented in this section are applicable for quench
addition, along with other scrubbing system components, or quench
replacement in an existing gas cleanup system
These costs also apply to high-temperature quench operation, so they
are not applicable for facilities utilizing waste heat boilers
5.1.3 Assumptions and User Guidelines
Spray tower quenches are assumed for cost estimating purposes. This
type of quench design is frequently supplied as a separate equipment
item.
For standard service (low acid), quench towers are constructed of
steel, lined with monolithic gunned refractory. For severe acid
environments (up to 2 percent HC1 in the gas), quenches are lined
with dense, acid-resistant brick backed with an acid-resistant shell
coating. Costs for these quenches can be considered virtual
worst-case costs.
Inlet gas temperatures range from 2,000° to 2,300°F. Vendors
contacted during the course of this study indicated little difference
in cost over this inlet temperature range. Outlet temperature is
<200°F.
Quenches come equipped with feedwater, drain, and gas inlet/outlet
connections, spray nozzles and fittings, and booster pump
5.1.4 Costs
Figure 6 presents purchased equipment costs for quench systems as a
function of mass flowrate of gas at the inlet, (Fjg)j. (FTQ)I is a function
of incinerator design, excess air rate, and fuel composition, and can be
calculated by the methods shown in Section 3.4.7 of Reference 1. All costs
are based on budgetary estimates from vendors.
Installation costs include the foundation, feedwater connections,
ducting, and refractory installation (if the unit is field erected).
Installation costs will vary from 30 to 50 percent of purchased equipment cost
depending on whether the unit is field erected or packaged. These
installation costs also assume that space is available to install the unit.
Installation cost can double for quench replacement in facilities with tight
space constraints.
To obtain the total retrofit cost, indirect costs such as engineering,
construction field expenses, and contingency must be added to the installed
equipment cost. The calculation procedures are presented in Section 3 of this
report.
22
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No significant additional operation and maintenance costs due to retrofit
are anticipated beyond those associated with the quench itself. Operation and
maintenance costs can be calculated as per Reference 1.
5.2 WASTE HEAT BOILERS
5.2.1 Description and Purpose of Retrofit
Waste heat boilers are potential cost saving alternatives to full-scale
quench systems. They recover energy by making steam with the heat recovered
from cooling the incinerator exhaust gas stream to 450° to 550°F. After the
gas leaves the waste heat recovery system, a low-temperature quench is needed
to cool the gas to <200°F to protect the downstream scrubber (see
Section 5.3).
5.2.2 Applicability and Limitations
A waste heat recovery boiler may be applicable if:
A need exists for the steam
Alkalai metals or other low-fusion temperature inorganics which cause
substantial fouling problems are not present in the waste feed
The cost of the waste heat boiler and associated equipment
(downstream quench) relative to the cost of a full-duty quench is
justified by the steam provided
5.2.3 Assumptions and User Guidelines
Firetube or watertube boilers may be used for energy recovery,
although firetube designs are preferred, particularly in smaller
facilities
Inlet gas temperatures may range from 1,600° to 2,200°F with little
impact on cost, based on vendor-supplied information. Exit gas
temperatures are 450° to 550°F.
Costs include the packaged boiler system plus standard trim
(feedwater connection and regulator, blowoff valves, etc.), but no
platforms, ducting, or control interface with upstream or downstream
subsystems
e Watertube boilers are all baretube construction. One cost curve is
provided for units of standard construction, and a second curve is
provided for high HC1 and high particulate service applications.
24
-------
5.2.4 Costs
Figure 7 presents purchased equipment costs of waste heat boilers as a
function of mass flowrate of flue gas (FTQ)J. These costs are based on vendor
estimates.
Installation costs include foundations, feedwater connections, ducting,
and startup. Installation costs for retrofit may range from 100 to
200 percent of the purchased equipment cost when the complete system is
installed (depending on the size of the equipment and difficulty of finding a
clear space for the boiler to be installed). Installing the boiler on an
existing foundation to lines already in place, without extra ducting and
piping, may run 30 percent of the purchased equipment cost. However, a
minimum installation cost factor of 50 percent is recommended to account for
platforms and control interfacing with other system components.
To obtain the total retrofit cost, indirect costs such as engineering and
construction field expenses and contingency costs should be added to the
installed equipment cost. These additonal costs should be calculated as in
Section 3 of this report.
Operation and maintenance costs for retrofit applications are not
expected to differ from those presented in Reference 1 and should be
calculated in the same manner.
5.3 LOW-TEMPERATURE QUENCHES
5.3.1 Description and Purpose of Retrofit
Low-temperature quenches are used to saturate the waste heat boiler
exhaust gas with water and cool it enough to protect downstream equipment.
This practice is not critical if a venturi scrubber is installed downstream,
however, it is important if only an acid gas absorber is utilized. Since the
inlet gas for this application (400° to 600°F) is much cooler than for the
high-temperature quenches (1,600° to 2,400°F), low-temperature quenches will
be somewhat less expensive. The largest portion of the cost difference arises
from the lower temperatures which do not require a refractory-lined chamber.
5.3.2 Applicability and Limitations
A small quench system will be needed in situations where a waste heat
boiler exhausts to an APCD which requires a low (170° to 190°F) entrance
temperature.
5.3.3 Assumptions and User Guidelines
Low-temperature quenches are similar to high-temperature quenches except
that the lower inlet temperatures require a smaller volume, no refractory
lining, and fewer spray nozzles. As in the high-temperature quench systems,
the exhaust gas is quenched to saturation.
25
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1 111 i I
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2 46810 20 40 60 80 100
Inlet Gas Flowrate, (FTG)J (1,000 Ib/hr)
200 300
Figure 7. Purchase cost of waste heat boilers (July 1982),
-------
5.3.4 Costs
Figure 8 presents purchased equipment costs for low-temperature quench
systems as a function of the waste heat boiler exhaust gas flowrate (Fyg).
FJQ is defined for high-temperature quenches (Section 5.1).
Installation costs are approximately 30 percent of delivered equipment
cost. This cost should not be significantly different for a retrofit
installation because these are relatively small systems, unless space
constraints are critical. A reasonable allowance for freight is 5 percent of
the purchased cost. To obtain the total retrofit cost, indirect costs such as
engineering and construction field expenses and contingency costs must be
added to the installed equipment cost. These additional expenses are
calculated as per Section 3 of this report. The installation of a small
quench will affect operation and maintenance costs only as indicated in
Reference 1.
27
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SECTION 6
SCRUBBING SYSTEM ADDITION/REPLACEMENT/MODIFICATION
Based on RCRA performance standards for hazardous waste incineration
facilities, scrubbing system retrofit may be required to achieve either or
both of the following requirements:
Reduce particulate loading in the flue gas to £0.08 gr/dscf, and/or
Improve HC1 removal efficiency to _>99 percent, if the waste feed
contains >0.5 percent organically bound chlorine
Depending on the design and performance of the existing scrubbing system (if
any), retrofit requirements may range from relatively minor adjustments in
operation to the addition of a complete quenching/scrubbing/flue gas handling
system. In certain cases, it may be possible for a facility to comply with
the particulate control requirement simply by increasing pressure drop across
an existing venturi scrubber. This assumes, of course, that the existing
scrubber and fan are somewhat overdesigned for the original operating
conditions. At the other extreme are older incineration facilities designed
without particulate or HC1 emission controls. In these cases, complete
scrubbing and flue gas handling systems may need to be installed to comply
with RCRA standards.
A myriad of potential retrofit scenarios exist between these extremes.
Within the limits of this study, it was not possible to address every
possible retrofit scenario. Therefore, the analysis is limited to retrofit
cases where major capital additions or modifications are required. These
scenarios are:
Complete system addition, including quench, venturi scrubber,
caustic recycle acid gas absorber, ID fan, and stack
Particulate scrubbing system addition or replacement, including
venturi scrubber and ancillary equipment
Acid gas absorption system addition or replacement
Acid gas absorption system modification for caustic recycle
operation
29
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Costs for these four retrofit scenarios are presented in the following
sections. Section 7 addresses the costs for situations where only the flue
gas handling system (fan, stack), and not the scrubbing system, requires
modification.
6.1 COMPLETE SYSTEM ADDITION
6.1.1 Description and Purpose of Retrofit
In older hazardous waste incineration facilities designed without
emission control equipment, addition of a complete gas-conditioning,
particulate and HC1 scrubbing, and flue gas handling system may be required
to meet RCRA standards. For the purposes of this study, a "complete system"
is assumed to include an in-line high-pressure spray quench, venturi
scrubber, cyclonic separator with an integral packed tower absorber, caustic
recycle system, ID fan, and exhaust stack, plus ductwork, piping, platforms,
foundations, and controls.
6.1.2 Applicability and Limitations
The addition of a complete scrubbing system is primarily applicable to
older incineration facilities constructed before the advent of strict
regulations for particulate and HCl emissions. The costs presented below are
for complete scrubbing systems designed to remove both particulate and HCl in
accordance with current regulatory requirements. These costs are based on
estimates from several vendors, and reflect modern design practices for HWI
applications. However, they may not be applicable for all facilities
because:
It is assumed that all equipment is provided by a single turnkey
vendor. Costs for scrubbing systems constructed
component-by-component may be lower or higher, depending on the
specific facility design and other economic factors.
Quenching, particulate scrubbing, and acid gas absorption equipment
design and materials of construction may differ from those assumed
in this study. The design features and materials of construction
assumed herein are common for HWI applications, but variations do
exist. For example, ionizing wet scrubbers (IWS's) may be used in
place of venturi scrubbers for particulate control in larger
facilities. These types of trade-offs are discussed later in this
section.
6.1.3 Assumptions and User Guidelines
A complete scrubbing/gas handling system is assumed to include the
components listed in Table 2. The approximate contribution of each component
to the total system cost is also listed. These guidelines are based on
vendor-supplied information.
30
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TABLE 2. SCRUBBING/FLUE GAS HANDLING SYSTEM COMPONENT COST BREAKDOWN
Component
In-line quench, venturi , wetted elbow
Cyclonic separator, integral packed
tower absorber
Caustic system
ID fan
Stack
Ductwork
Piping
Platform, foundations
Instrumentation and controls
TOTAL
Percentage of total
system cost
9
30
17
18
10
3
3
4
6
100
Critical compnent materials of construction are:
High nickel alloy quench, venturi throat, and wetted elbow
High-grade, chemically resistant, high-temperature fiberglass resin
with a thick fiberglas shell for the cyclonic separator and packed
tower
Polypropylene tower packing
Inconel or Hastelloy fan wheel with a rubber-lined steel housing
Baseline costs are for a 30-in. W.C. venturi pressure drop, which is typical
for HWI applications.
6.1.4 Costs
Typical purchased costs for scrubbing/flue gas handling systems
receiving combustion gas directly from the incinerator are presented in
Figure 9. The inlet gas flowrate (qgi) in acfm is given by:
r^
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4 6 10 20 40 60
Inlet gas flowrate, (1,000 acfm)
100
200 300
Figure 9. Purchase cost of scrubbing systems receiving 1,800° to 2,200°F
gas (July 1982).
-------
where (qiG)i = volumetric gas flowrate at the incinerator exit (scfm)
T = incinerator exit gas temperature (°F)
The costs shown previously in Figure 9 are based on a design inlet
temperature of 2,200°F, and a venturi pressure drop of 30-in. W.C., which are
typical conditions. For "worst case" pressure drops of 100-in. W.C., the
total system cost is approximately twice that shown in Figure 9 due to more
rigorous structural requirements and the inclusion of multiple high-head
fans.
Figure 10 presents purchased costs for the same basic scrubbing systems
designed to handle approximately 500° to 550°F gas from waste heat boilers.
Differences in cost for these scrubbing systems versus the scrubbing systems
designed for 2,200°F inlet gas reflect the differences in quench duty and
saturated gas flowrates through the venturi, absorber, and fan.
Installation costs for scrubbing systems are typically about 50 percent
of the purchased equipment cost, although they may run 100 percent of the
purchased cost in difficult retrofit cases. Depending on location, freight
costs may run 5 to 10 percent of the purchased cost. To obtain the total
/*~\ retrofit cost, it is also necessary to factor in indirect costs and
contingency as specified in Section 3.
O&M costs will almost certainly be increased by scrubber system
performance upgrading regardless of whether the complete system, or only
components thereof, are retrofitted. Incremental O&M costs due to upgrading
can be projected from "before" and "after" O&M cost estimates using the
methods given in Reference 1.
6.2 PARTICULATE SCRUBBING SYSTEM ADDITION/REPLACEMENT
In many cases, it may not be necessary to include HC1 absorption
capability in the retrofitted scrubbing system. The purpose of this section
is to estimate the total installed costs of retrofitting venturi scrubbing
systems into hazardous waste incineration facilities for control of
particulate emissions only, not HC1 or other acid gases. The degree of
particulate control is determined by the requirements set forth in the RCRA
Incinerator Standards for Owners and Operators of Hazardous Waste Management
Facilities, Subpart 0. The January 23, 1981 Interim Final Rule (promulgated
June 24, 1982) requires control of particulate matter to a level not
exceeding 180 mg/dscm corrected to 12 percent COg (0.08 gr/dscf). For
purposes of this retrofit cost study, a range of values from 0.08 to
0.03 gr/dscf have been evaluated. As particulate emission requirements
become more stringent, the subsequent venturi scrubber performance demands
and costs will increase accordingly. This section estimates these
relationships.
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Figure 10. Purchase cost of scrubbing systems receiving 500° to 550°F gas
(July 1982).
34
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6.2.1 Description and Purpose of Retrofit
Participate matter in hazardous waste incinerators is formed from metal
salts in the waste, metal oxides formed in combustion, and products of
incomplete combustion. Most existing incinerators control particulate
emissions with a venturi scrubber. Venturi scrubbers operate on the
principle that high relative velocities between the gas to be-cleaned and the
scrubbing liquid promote particle collection. Migh relative velocities in
the venturi scrubber are achieved in the converging section. Liquid is
introduced at a point where the gas stream has reached high velocities,
causing atomization of the liquid and entrainment in the gas stream. Dust
particles are trapped by droplets in this turbulent region and subsequently
removed from the gas stream, typically in a cyclonic separator, which is an
integral component of the scrubbing system.
Other pollution control devices have been considered for use in
hazardous waste incinerators, such as baghouses, cyclones, and electrostatic
precipitators (ESP), but the vast majority of existing facilities employ
venturi scrubbers. Baghouses are unable to withstand the temperature and
corrosivity, and water buildup can blind bags. Cyclones cannot obtain the
required efficiency with the relatively small particulate typical of these
facilities, and ESP's have a high capital and operating cost.
IWS's are gaining in popularity. IWS's are capable of simultaneously
removing corrosive gases and particulate material. Particles are
N electrostatically charged in an ionizer section prior to passing through a
packed bed scrubbing section where a caustic scrubbant enters crossflow with
the gas stream. While capital costs for the IMS are substantially higher
than conventional venturi systems, operating costs appear to be lower. This
is a result of the low pressure drop of the IMS relative to a venturi
scrubber, thus saving on induced draft (ID) fan costs and electrical
operating costs. This electrical energy saving is somewhat offset by the
power required in the ionizer section. Detailed IWS vendor quotes for
retrofit cases will be supplied in a subsequent report serving as an addendum
to Reference 1.
For purposes of this analysis, it is assumed that existing particulate
controls, if any are employed, have been designed to meet regulations which,
in general, are less stringent than 0.08 gr/dscf. Particulate emission
standards from 0.08 to 0.03 gr/dscf are being evaluated in this study for
their impact on scrubber retrofit costs. Therefore, these new emission
standards require an upgrading of scrubber performance. In theory, this can
be done by either modifying an existing scrubber (specifically, increasing
pressure drop to improve collection efficiency) or by replacing an existing
unit with one capable of better performance. Given the assumption of the
need for substantial performance improvement, modification can be eliminated
as an option. Structural requirements greatly limit increases in pressure
drop essential to improved performance. Thus, only the complete replacement
option has been considered.
V,
35
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6.2.2 Applicability and Limitations
Guidelines are presented in the following paragraphs to determine the
total retrofit cost of a replacement venturi scrubber system for a range of
inlet gas flowrates. Guidelines are also given for determining required
pressure drops across the venturi scrubber in order to achieve the specified
particulate emission rates. Since these guidelines are only approximations
developed for this study, and subject to specific assumptions detailed below,
they should not be used in a quantitative design sense. This can only be
done if a facility's actual incinerator outlet particle size distribution is
known. Venturi scrubber performance is highly dependent on such data. If
such data are available, the more detailed methods presented in Reference 1
can be used to estimate pressure drop requirements.
6.2.3 Assumptions and User Guidelines
In this study and in Reference 1, it is conservatively assumed that
particulate removal devices such as venturi scrubbers are required if the
particulate loading in the incinerator effluent is greater than the desired
outlet loading. Incidental removal in pot-type quench systems, fallout to
waste heat boiler dust hoppers, and incidental removal in acid gas absorbers
can provide some particulate control for large particle sizes, but very
little control of submicron particulate.
Venturi pressure drop requirements are sensitive to the required
particulate removal efficiency, and quite sensitive to the aerodynamic
particle size distribution. Typical pressure drop requirements are a 20- to
40-in. W.C., with a 30-in. W.C. being a good midrange value for first cut
estimating purposes. However, pressure drop requirements may range up to
100-in. W.C. for >98 percent collection of extremely fine submicron
particulate. Virtual worst-case pressure drop requirements are shown in
Table 3* as a function of the required outlet grain loading and collection
efficiency. These values are based on a conservative inlet grain loading of
2 gr/dscf and a mean aerodynamic particle diameter of 0.7 pm.
6.2.4 Costs
As indicated in Section 6.1.3, the quench/venturi scrubber typically
account for 9 percent of the purchased cost of a complete scrubbing/flue gas
handling system. Even for the optimum retrofit scenario, however, where the
existing cyclonic separator, fan, stack, and scrubber controls can still be
utilized, additional (new) ductwork and piping will be needed when the
quench/venturi scrubber are replaced. Thus, the equipment costs for this
"best case" retrofit scenario are approximately 15 percent of the total
system costs presented in Figures 9 and 10.
*More detailed methods to estimate pressure drop requirements are given in
Reference 1.
36
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TABLE 3. PRESSURE DROP VERSUS OUTLET PARTICULATE LOADING AND
COLLECTION EFFICIENCY*
Outlet particulate loading Collection efficiency Pressure drop
(gr/dscf) (percent) (in. W.C.)
0.08
0.07
0.06
0.05
0.04
0.03
96.0
96.5
97.0
97.5
98.0
98.5
40
45
55
65
80
100
Conservative values based on an inlet grain loading of 2 gr/dscf and a
mean aerodynamic particle diameter of 0.7 ptn.
In many cases, it may be necessary to add or replace a complete
particulate scrubbing system, including the quench/venturi, cyclonic
separator, ID fan, and stack, plus ductwork, piping, platforms, foundations,
and controls. Equipment costs for this retrofit scenario are approximately
55 to 65 percent of the total system purchased costs presented in Figures 9
and 10.
The previously mentioned costs are based on a "typical" venturi pressure
drop requirement of a 30-in. W.C. The values presented in Table 3 are based
on a very conservative inlet grain loading and particle size distribution.
For the virtual worst case pressure drop requirement of a 100-in. W.C.,
purchased costs for complete particulate scrubbing systems (but no acid gas
absorption) are approximately 110 to 130 percent of the costs presented in
Figures 9 and 10.
Installation, freight, and indirect cost factors are approximately the
same as those presented in Section 6.1.4 for complete HWI scrubbing systems.
6.3 ACID GAS ABSORPTION SYSTEM ADDITION/REPLACEMENT/MODIFICATION
The purpose of this section is to estimate the total installed costs of
either increasing the performance of an existing absorber or of retrofitting
an acid gas absorber into a hazardous waste incinerator for control of HCl
emissions. The degree of HCl removal is set forth in the RCRA Incinerator
Standards for Owners and Operators of Hazardous Waste Management Facilities,
Subpart 0. The January 23, 1981 Interim Final Rule requires 99 percent HCl
removal efficiency for incinerators burning wastes containing more than
0.5 percent chlorine. There is no requirement for incinerators burning
wastes containing less than 0.5 percent chlorine.
37
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6.3.1 Description and Purpose of Retrofit
There are three options that may be available to owners and operators of
hazardous waste incinerators to meet the 99 percent removal efficiency
requirement.
1. Increase efficiency of an existing acid gas absorber by adding
transfer units (i.e., increasing packed bed depth in a packed bed
absorber or adding trays in a tray tower absorber).
2. Increase efficiency on an existing once-through water scrubbing unit
by changing to a caustic recycle system.
3. Retrofit an absorber to an existing incinerator.
Option 1 is not considered in this analysis because the gains in HC1 removal
efficiency obtained by adding packed bed depth or trays is usually marginal,
unless the original design is completely inadequate. For a given increase in
efficiency, packed bed depth increases exponentially to a realistic maximum
of approximately 10 ft. Beyond that depth, liquid channeling becomes a
problem and may actually be detrimental to efficiency.
This section presents the cost relationships for the remaining two
options.
6.3.2 Applicability and Limitations
Guidelines are presented in the following paragraphs to determine:
(1) the total retrofit cost of increasing HC1 removal efficiency of an
existing absorber by changing scrubber liquid systems, and (2) the retrofit
cost of replacing an existing absorber. Because these guidelines are only
approximations and subject to the specific assumptions detailed below, they
should not be used in a quantitative^design sense. This can only be done if
operating parameters of the facility in question are known. In general,
however, the retrofit of an acid gas absorber should not be a difficult
project in terms of space requirements. Absorber units are vertical
structures of relatively small diameters, and should not present undue
difficulties. Cost guidelines presented here are generally applicable to all
facilities burning chlorinated wastes containing in excess of 0.5 percent
chlorine.
6.3.3 Assumptions and User Guidelines
Partial removal of HC1 is achieved in quench systems and in venturi
scrubbers, although an HCl removal efficiency in excess of 90 percent usually
requires the addition of an absorber. Once-through water absorbers can
achieve the required 99 percent HCl removal in many cases. In certain
retrofit situations, however, conversion to caustic scrubbing will be
required.
38
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Packed bed or tray tower absorbers can be used for HC1 removal with
reasonably similar capital and operating costs. Lime or caustic soda can be
used for HC1 neutralization. For the purposes of this study, caustic soda
solution scrubbing in packed towers absorbers is assumed as explained in
Section 6.1.3.
There is some finite amount of water in the fired waste so that the
adiabatic saturation temperature remains relatively low (less than 180°F) at
the inlet of the packed bed absorber. There is a negligible amount of free
chlorine in the flue gas, thus obviating the formation of sodium
hypochlorite, a strong oxidant that attacks most packing materials. It is
assumed that no hydrogen fluoride is present in the flue gas. If any one of
these conditions is not met, then a more expensive packing material such as
Kynar, may have to be used, raising the cost of the APCD system up to
50 percent.
6.3.4 Costs
Equipment costs for complete acid gas absorption systems, without
venturi scrubbers for particulate control, are approximately 85 percent of
the costs for complete scrubbing systems shown in Figures 9 and 10.
Correspondingly, the costs for conversion to a caustic recycle system run
about 25 percent of the costs presented in Figures 9 and 10. This includes
allowances for the recycle tank and pumps, additional piping, and pH
controls.
Installation, freight, and indirect cost factors are roughly the same as
those presented in Section 6.1.4.
39
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SECTION 7
FLUE GAS HANDLING EQUIPMENT
Flue gas handling equipment in an incinerator system includes the
following components:
Ductwork
Fan and motor
Exhaust stack
Major cost impacts on gas handling equipment due to air pollution control
equipment addition/modification or stringent environmental regulation would
fall on the fan and stack systems. Ductwork modification costs are
relatively minor, and have already been included with the various APCD
modifications. The addition or modification of APCD's may require a higher
pressure drop capacity fan. Local environmental regulations may require
taller exhaust stacks for better pollutant dispersion. The scrubbing system
retrofit costs presented in Section 6 generally include allowances for new
fans and stack. However, separate fan and stack costs are presented in this
section for situations in which only these equipment items, and not the
scrubbing system components themselves, need to be replaced.
7.1 INDUCED DRAFT FAN ADDITION/REPLACEMENT
7.1.1 Description and Purpose of Retrofit
In hazardous waste incineration systems, induced draft (ID) fans are
commonly used to move the incinerator off-gas through the system. In the
following discussion, the term "fan" refers to the complete fan and motor
assembly. These fans are usually located downstream of any pollution control
equipment. The fans are designed for a specific pressure drop (AP) and range
of gas flowrates. Small AP changes can be accommodated by an existing fan.
However, should the AP increase significantly (>5-in. W.C.) due to added.
upstream equipment and ducting or modified operation, more pressure head must
be supplied by the fan system. This is done either by adding a booster fan
in series with the existing fan or replacing the fan with one of higher
capacity.
40
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7.1.2 Applicability and Limitations
There are no strict rules to determine when to add a booster fan as
opposed to replacing the existing fan. The advantages and disadvantages of
each should be determined on a case-by-case basis. One general rule is not
to connect more than two fans in series. This creates complicated control
schemes making the fan system difficult to operate. In general, more than
two fans in series may be required if pressure head requirements are over a
100-in. W.C.
Several factors affect the choice of adding a booster fan versus
replacing the existing fan due to upstream air pollution control equipment
changes. These include:
Space limitations
Pressure drop increase
Change in stream conditions (moisture content, acid content, etc.)
If space is not available for ducting and an extra fan, one way to decrease
space requirements would be to replace the existing fan with one that will
meet the added requirements. If the pressure load required is increased
significantly by adding upstream pollution control equipment and/or simply
increasing venturi scrubber AP, two fans in series might need to be added to
the existing fan to add the necessary pressure load. This creates the
control problem mentioned earlier. In that case it might be preferable to
replace the existing fan with two new fans in series which provide all the
required pressure load. A change in stream conditions may make the existing
fan incapable of easy operation even with a booster fan. In this case, the
existing fan might have to be replaced.
7.1.3 Assumptions and User Guidelines
Retrofit fan (including motor) costs were estimated based on assumed
pressure drops for the various pieces of equipment and applying these
pressure drops over a range of gas flowrates. The assumed pressure losses
for the various pieces of equipment are as follows:
o Incinerator 4- to 5-in. W.C.
Waste heat boiler 4-in. W.C.
Quench 1-in. W.C.
Venturi scrubber 20- to 100-in. W.C,
Acid gas scrubber 2- to 7-in. W.C.
Oemister 1- to 10-in. W.C.
41
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An overdesign factor of 25 percent was used on pressure load. With the above
pressure losses and the overdesign factor, the pressure load range of
interest is a 40- to 160-in. W.C.
The fan costs are based on several material considerations. The fan
shafts and blades are exposed to 140° to 180°F saturated gas with
approximately 0.02 percent by volume acid. Therefore, these parts are
assumed to be Inconel or Hastelloy for corrosion resistance. The fan housing
and inlet box are assumed to be rubber-lined carbon steel. If acid or
alkaline waste is not going to be fired in the incinerator, carbon steel,
which is much cheaper than Inconel or Hastelloy, could be used for the fan
blades and shafts.
7.1.4 Costs
Cost curves for fans in various gas flowrate and pressure drop ranges
are presented in Figures 11 and 12. These costs include:
Fan wheels and shafts
Electric motor(s) and controls
Inlet box and damper
Cooled bearing with vibration and temperature sensors
Coupling and interconnecting ducting, where applicable
As shown in Figures 11 and 12, the cost of carbon steel fan is less
than for corrosion-resistant fans.
Careful consideration should be given before using these costs because
fan costs are very dependent on fan type. For example, several vendors do
not offer fans which can supply 160-in. W.C. pressure; however, others have
machines which can supply that pressure but have flow limitations. Also, fan
design affects the cost. One manufacturer could not supply costs for a
rubber-lined housing because his fan design does not permit lining the
housing. Therefore, his costs were higher because the housing is costed as
corrosion-resistant stainless steel.
Below a gas flowrate of 10,000 acfm, fan costs become dependent on fan
type. Several vendors needed special fan designs requiring fairly complex
manufacturing procedures to give a high-pressure head fan (>40-in. W.C.),
whereas vendors of fans of a different design could supply the required low-
flow and high-pressure fan from one of "standard design."
Installation of fans usually takes approximately 6 to 8 man-weeks with
a crane needed for approximately 1/2 to 2 days. Installation costs are
usually less than $20,000 to $30,000. These costs include:
42
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Purchase cost ($1,000)
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There is very little dependence of installation costs on fan size.
However, if two fans are being installed, costs are higher because of
interconnecting ductwork erection, added crane rental, and labor.
Maintenance procedures on these fans should be no different than those
for the existing fans. Thus maintenance costs should be calculated in the
same manner as given in Section 5 of Reference 1. However, should a booster
fan be added to an existing fan, or two fans be used to replace a single
existing fan, the maintenance costs will be greater than for the single fan
case. This is reflected in Reference 1 as a function of the difference in
capital cost. Operation costs will be no different than for the existing fan
except for the additional power costs. This cost can be calculated using the
formula contained in Section 3.6 of Reference 1.
Finally, to obtain total retrofit costs, indirect costs such as
engineering and construction field expenses and contingency costs must be
added to the installed equipment costs, as specified in Section 3.
7.2 STACK REPLACEMENT
7.2.1 Description and Purpose of Retrofit
Small diameter stacks are used to vent the flue gas from incinerator
systems, the purpose being to discharge the combustion products away from the
immediate work area. However, an existing stack may have to be replaced with
one of taller design to meet a local ordinance and/or to achieve better
dispersion of the waste products.
In general, stacks can be constructed from a variety of materials,
including:
Fiber-reinforced plastic (FRP)
Carbon steel
Stainless steel
Refractory-lined carbon steel
Monel or Hastelloy
Because hazardous waste incinerators often fire acid- or alkali-producing
wastes, carbon steel and possibly stainless steel cannot be utilized because
45
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of corrosion problems. Carbon steel stacks lined with acid resistant plastic
have been utilized, but thermal expansion incompatibility problems have been
reported in limited applications. The exotic materials such as Hastelloy are
too expensive except for special applications. FRP stacks are the preferred
design because of their lower cost and high corrosion resistance, but can
only be used if the incinerator has a downstream quench and scrubber system
which cools the flue gas to at least 250°F before it reaches the stack. If
high-temperature exhaust gases must be vented, then a corrosion-resistant
refractory brick-lined carbon steel stack is generally specified.
Small diameter stacks up to 6 ft in diameter have been installed up to
200 ft high by proper use of guy wires.
7.2.2 App 1 icabi 1 ity and Limit a t ion s
Incinerator systems with quench and APCD equipment generally use FRP
stacks. If an emergency vent stack is required or if the incinerator
routinely exhausts its hot gases directly to the stack, then the
refractory-lined stack is called for. The actual selection and design of the
stack must be done on site-specific basis.
As to design diameter and height limitations, those must be based on
local ordinances, meteorology, topography, geology, etc. Some guidelines are
given in the following paragraphs.
7.2.3 As s umpt i on s^ and^ User^ JkruJel i n es
It is assumed that the stack is free standing, e.g., not an integral
part of an acid gas scrubber column. A retrofit or replacement stack usually
costs no more than a "grass roots" stack. The new stack is merely erected
next to the old one, and the appropriate ductwork and breeching connected.
A rough design guideline for stack diameter D is given by
0.5
D =
TG
/T » 460\
\ 520 "7
60
where qjQ is the total flue gas flowrate (scfm) calculated in Section 3 of
Reference 1, T(°F) is the exhaust gas temperature (exact temperature
dependent on APCD configuration), and v is the stack exit gas design
velocity, usually 40 to 60 ft/s.
7.2.4 Costs
Figures 13 and 14 present fabricated costs of FRP and refractory-lined
steel stacks, respectively, as a function of stack height and diameter. Note
that costs are fairly linear with stack height. Indeed, stacks are usually
46
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erected from prefabricated 20- to 40-ft flanged sections. The costs of
refractory-lined stacks are nearly double that of FRP stacks.
A good estimate of installation costs for either design is that
installation costs are comparable to the fabricated material costs. Finally,
indirect costs such as engineering and construction field expenses and
contingency costs must be added to the installed cost to obtain total the
retrofit cost, as specified in Section 3.
No additional operational or maintenance impacts are expected with the
new stack.
47
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50
40
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20
.a
a
10
5 ft
diameter
3 ft
Diameter
1 ft
diameter
50 100
Stack height (ft)
150
Figure 13. Fabricated cost of FRP stacks (July 1982)
48
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90
80
70
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I 40
30
20 _
50 100
Stack height (ft)
5 ft
diameter
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1 ft
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150
Figure 14. Fabricated cost of refractory-lined steel stacks (July 1982)
49
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SECTION 8
TOTAL INCINERATION SYSTEM REPLACEMENT
Upgrading an aging hazardous waste incineration system by component
modification or retrofit to meet regulatory compliance may not necessarily be
the optimum choice. Total system replacement may be preferred. The actual
decision may be based on a number of business factors, although the physical
condition of the existing equipment and the comparative costs of retrofit
versus total system replacement are key criteria.
8.1 DESCRIPTION AND PURPOSE OF REPLACEMENT
If the existing incinerator and air pollution control system is beyond
its economic life for tax depreciation purposes and major capital additions
or modifications are required for regulatory compliance, then total system
replacement may be applicable. Total system replacement may also be
appropriate if the annualized capital and operating costs of the proposed new
system are less than those projected for the existing system after
modification. Finally, total system replacement may be the only reasonable
alternative if the existing system cannot be effectively retrofitted, e.g.,
because of equipment obsolescence. However, other political and
business-related factors will also impact the decision.
As defined here, an incineration system includes all equipment necessary
to burn hazardous waste in compliance with existing and likely near-term
regulations. Equipment includes:
Incinerator proper, with associated ash-handling equipment
Quench and/or waste heat boiler
Venturi scrubber
Acid gas absorber
Flue-gas-handling equipment
Ductwork
Fan and motor
-- Stack
Instrumentation and controls
50
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The costs presented in this section do not include allowances for waste heat
boilers. However, Figure 7 in Section 5.2 can be used to estimate
incremental costs for waste heat boiler addition, if desired. Costs for
waste storage and handling equipment are also deleted herein due to their
site-specific nature. If necessary, however, these costs can be estimated as
shown in Sections 3 and 4 of Reference 1.
8.2 APPLICABILITY AND LIMITATIONS
Total system replacement is a potential option available to all
hazardous waste incineration systems facing major capital additions or
modifications. Economics and the ability to meet regulatory performance
standards will be the major deciding factors. Repermitting requirements and
limitations, including state and local, must also be considered.
8.3 ASSUMPTIONS AND USER GUIDELINES
Total system replacement makes sense only if major capital expenditures
are necessary to bring the existing incinerator system up to compliance. To
determine whether a new system is more viable, first the cost of upgrading
the existing system by component must be estimated, using the guidelines
presented in Sections 4 through 7. Note that the existing system may need a
combination of retrofits, e.g., a new combustion chamber, venturi scrubber,
and fan and blower assembly. These projected retrofit expenditures can then
be annualized along with associated operation and maintenance costs and
^ combined with the annualized capital carrying charges and operation and
^ maintenance costs of the existing facility. This combination gives the total
annualized capital and operating costs of the proposed modified facility.
These projected costs can then be compared with the estimated annualized
capital and operating costs of the proposed new facility. The remaining
lifetime of the modified facility can be estimated from the physical
condition of the equipment, the kind of wastes fired, and the operating
environment (e.g., operating hours in a year, cyclic versus continuous
operation, erosion and corrosion potential of the exhaust gas, etc.). The
lifetime of a new incinerator system is estimated to be approximately 15 to
20 years for depreciation purposes.
This is only one method of evaluating the merits of total system
replacement versus existing system upgrade. The user can apply alternative
criteria.
8.4 COSTS
Purchased equipment costs of complete liquid injection, hearth, and
rotary kiln hazardous waste incineration systems were obtained from vendors
who offer complete systems. These estimated costs are shown graphically in
Figures 15 through 17 as a function of heat input capacity. The systems
include all the equipment discussed earlier, including the air pollution
control devices for particulate and acid gas removal. The costs are
necessarily generalized estimates because incinerator system costs are
r
51
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dependent on the properties of the waste fired, but the costs should be good
budgetary estimates (±30 percent), well within the accuracy requirements of
this study, and suitable for making preliminary retrofit decisions. As
expected, a new, complete incineration system usually costs less than the sum
of the retrofit costs for individual components.
Installation costs were estimated by the vendors to be 30 to 50 percent
of the purchased equipment cost, depending on degree of prefabrication, and
freight costs should run about 5 percent. To obtain the total facility cost,
indirect costs such as engineering and construction field expenses and
contingency costs must be added to the installed cost, as specified in
Section 3.
Operation and maintenance costs can be estimated per Reference 1.
55
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SECTION 9
DOWNTIME CONSIDERATIONS
A less obvious cost of retrofitting or modifying components of an
incinerator system is downtime cost. If an operating incineration system
must shutdown for installation of new equipment or modifications, then the
real costs associated with that downtime should be included in the total
cost to achieve regulatory compliance. However downtime costs are nebulous
and difficult to estimate because (1) the allocation of costs during this
downtime is difficult to assess and (2) such costs are highly site specific.
Nevertheless, some general guidelines are presented here.
Costs incurred during incinerator downtime include:
Capitalized cost of original equipment, taxes, and insurance
Operating labor
Cost of alternate interim waste disposal for dedicated incineration
facilities
Lost revenue for commercial incineration facilities
Credit for fuel, utilities, etc. not used
The capitalized cost of the existing facility for the period of downtime can
only be estimated on a site-specific basis. Estimated installation times for
retrofitting various components of an incinerator system are given in
Table 4. Note that the times are only typical values; retrofit and startup
difficulties could easily double the times for component retrofits.
However, the downtime could actually be less than total installation
time. For example, erection of a scrubber could occur while the incinerator
continues to operate. The incinerator may only need to be shut down for the
1 to 2 days required to cut in the necessary ductwork, after erection of the
scrubber module. Thus, if true downtime is only on the order of days or a
week, modifications and or retrofits could be scheduled during a routine
maintenance outage to minimize costs. Such determinations must be made on a
site-specific basis.
Operating costs and "credits" are determined by the specific facility or
can be estimated using Reference 1 guidelines. The cost of alternate interim
56
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A
TABLE 4. ESTIMATED INSTALLATION TIMES FOR INCINERATOR SYSTEM COMPONENTS
Retrofit component Typical installation time3
Refractory 4 weeks
Burners 2 weeks
Combustion chamber 4 weeks
Quench 2 weeks
Waste heat boiler 4 weeks
Venturi scrubber 2 weeks
Acid gas absorber 2 weeks
Fan and motor 1 weeks
Stack 1 weeks
^ Total system
^ Small (10 to 20 million Btu/hr heat input) 3 months
Large (>20 million Btu/hr heat input) ' 3 to 6 months
alncludes startup, but not lead time for engineering design and
equipment fabrication.
57
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disposal is again highly site specific. Transportation of the waste to an
alternate facility can be very costly, depending on the nature of the
hazardous waste and the distance to the facility. Table 5 gives baseline,
bare minimum cost estimates for burning hazardous wastes. The costs are
those charged by a municipally owned incinerator, which offers its service
basically at cost.
In conclusion, downtime costs are highly variable and case specific.
Only general guidelines can be presented here.
58
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TABLE 5. BASELINE HAZARDOUS WASTE INCINERATION COSTS
Quantity of waste Base pricea»b»c
(million Ib/yr)
0 to 6 0.045
6 to 12 0.042
0.038
Surcharge or Credit for Heating Value
Heating value Surcharge Credit
(103 Btu/lb)
0-1 0.027
1-2 0.023
2-3 0.019
3-4 0.015
4-5 0.012
5-6 0.009
6-7 0.006
7-8 0.003
8-9 0 0
9-10 0.003
10-11 0.006
11-12 0.009
0.012
^Residue Surcharge
$0.013/lb ash
cAcidity Neutralization Surcharge
Surcharge = (W) x (Y)
where
W = Ib of neutralizing agent (NaOH)/lb of waste
Y = Cost of 50 percent caustic solution = $0.08/lb
59
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REFERENCES
1. McCormick, R. J., and R. J. DeRosier, "Capital and O&M Cost Relationships
for Hazardous Waste Incineration," Contract No. 68-03-3043,
U.S. Environmental Protection Agency, Cincinnati, Ohio, July 1983.
60
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing/
1, REPORT NO.
2.
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
5. REPORT DATE
'N. Retrofit Cost Relationships for Hazardous Waste
^ Incineration
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
K. Lirn, R. DeRosier, R. Larkin, R. McCormick
8. PERFORMING ORGANIZATION REPORT NO
9. PERFORMING ORGANIZATION NAME AND ADDRESS
1O. PROGRAM ELEMENT NO.
Acure>£ Corporation
555 Clyde Avenue
Mountain View, CA 94039
CBRD1A
11. CONTRACT/GRANT NO.
68-03-3043
12. SPONSORING AGENCY NAME AND ADDRESS
Industrial Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati, Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
6/1/82 - 7/1/83
14. SPONSORING AGENCY CODE
EPA/600/12
15. SUPPLEMENTARY NOTES
16. ABSTRACT
C
This study reports a methodology, and an accompanying set of empirical
cost relationships, that can be used to estimate the costs of retrofitting/
upgrading various components of existing hazardous waste incineration
facilities to comply with RCRA performance requirements. (Operation and
maintenance costs and costs for new facilities are addressed in a companion
report entitled, "Capital and O&M Cost Relationships for Hazardous Waste
Incineration.") Both the methodology and the retrofit cost relationships
were intended to focus on major capital additions or subsystem modifications
that could be required for RCRA compliance.
The results of the study are expressed in a series of empirical relationships
between the costs for various capital modifications/additions and factors that
significantly impact these costs, e.g., capacity, materials of construction, etc.
Costs are developed for (1) various aspects of combustion system retrofit to
improve destruction of toxic waste constituents, (2) scrubbing system component
addition, replacement, or upgrading to improve particulate and/or HC1 removal,
and (3) addition or replacement of ancillary equipment mandated by combustion
or scrubbing system retrofit. The costs are based on a combination of in-house
engineering and vendor-supplied budgetary cost estimates.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
11G
C
8. DISTRIBUTION STATEMEN1
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisReport)
UNCLASSIFIED
21. NO. OF PAGES
20. SECURITY CLASS (This page)
UNCLASSIFIED '
22. PRICE
EPA Form 2220-1 (Rev. 4-77} PREVIOUS COITION is OBSOLETE
61
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