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INTERIM GUIDE OF GOOD PRACTICE
FOR INCINERATION AT FEDERAL FACILITIES
prepared by
Engineering Branch
Division of Abatement
U. S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE
Public Health Service
Consumer Protection and Environmental Health Service
National Air Pollution Control Administration
Raleigh, North Carolina
November 1969
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The AP series of reports is issued by the National Air Pollution Control Adminis-
tration to report the results of scientific and engineering studies, and information
of general interest in the field of air pollution. Information reported in this series
includes coverage of NAPCA intramural activities and of cooperative studies
conducted in conjunction with state and local agencies, research institutes, and
industrial organizations. Copies of AP reports may be obtained upon request, as
supplies permit, from the Office of Technical Information and Publications,
National Air Pollution Control Administration, U.S. Department of Health, Educa-
tion, and Welfare, 1033 Wade Avenue, Raleigh, North Carolina 27605.
National Air Pollution Control Administration Publication No. AP-46
11
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CONTENTS
1 INTRODUCTION 1-1
1. 1 Purpose of Interim Guide of Good Practice 1-2
1.2 Applicability of Federal Regulations to Incinerators 1-Z
1.2. 1 Existing Incinerators 1-2
1.2. 1. 1 Modification of Incinerator 1-2
1.2. 1.2 Addition of Air Pollution Control Device 1-3
1.2.1.3 Replacement of Incinerator 1-3
1.2. 1.4 Alternative Method of Refuse Disposal 1-3
1. 2. 2 New Incinerators 1_3
1.3 Standards for Particulate Emissions 1-3
1. 3. 1 Incinerators of Over 200 Pounds per Hour Capacity 1-3
1. 3. 2 Incinerators of 200 Pounds per Hour Capacity and Less .... 1-3
1.4 Standards for Visible Emissions 1-4
1.4. 1 Incinerators Acquired On or After June 3, 1966 1-4.
1.4.2 Incinerators Acquired Prior to June 3, 1966 1-4
1. 5 Considerations for Good Planning Other Than Incinerator Design ... 1-4
2 DEFINITIONS OF INCINERATOR TERMS 2-1
3 WASTE CLASSIFICATIONS 3-1
4 RECOMMENDED INCINERATOR AND GAS WASHER DESIGNS 4-1
5 ALTERNATE INCINERATOR AND GAS WASHER DESIGNS 5-1
6 DESIGN RECOMMENDATIONS FOR GENERAL-REFUSE
INCINERATORS 6-1
6. 1 Basis for Design Recommendations 6-1
6.2 Types of General-Refuse Incinerators 6-1
6.2.1 Multiple-Chamber Retort Incinerators 6-1
6.2.2 Multiple-Chamber In-Line Incinerators 6-1
6. 3 Recommendations for Auxiliary Gas Burners 6-2
6. 3. 1 Incinerators Requiring Burners 6-2
6. 3. 2 Types of Natural Gas Burners Recommended 6-3
6.3.3 Sizes of Burners Recommended 6-6
6.3.4 Other Fuels 6-6
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7 DESIGN RECOMMENDATIONS FOR PATHOLOGICAL,
INCINERATORS 7-1
7. 1 Basis for Design Recommendations 7-1
7.2 Multiple-Chamber Pathological Incinerators - General 7-1
7.2.1 Pathological Retort Incinerators 7-1
7.2.2 Side Chamber for Pathological Refuse ?~2
8 DESIGN RECOMMENDATIONS FOR INCINERATOR SCRUBBERS .... 8-1
8. 1 General 8-1
8. 2 Scrubber Design Parameters 8-1
8. 3 Scrubber Controls 8-4
8. 4 Scrubber Construction 8-6
8.5 Induced-Draft Fan 8-7
8.5.1 General 8-7
8.5.2 Design Parameters 8-7
8.5.2.1 Volume Requirements 8-7
8.5.2.2 Static Pressure Requirements 8-7
8.5.2.3 Horsepower Requirements 8-7
8.5.2.4 By-Pass Arrangements 8-7
8.6 Mist Eliminators 8-8
8. 7 Alternate Scrubber Designs 8-8
9 RECOMMENDATIONS FOR CONSTRUCTION 9-1
9. 1 Materials of Construction 9-1
9.1.1 High-Temperature Block Insulation 9-1
9.1.2 High-Heat-Duty Firebrick 9-2
9.1.3 Super-Duty Firebrick 9-2
9.1.4 Class C Hydraulic Castable Refractory 9-2
9.1.5 Class D Hydraulic Castable Refractory 9-2
9.1.6 Use of Castable Refractories 9-3
9.1.7 Insulation Castable Refractories 9-3
9.1.7.1 Class Q Insulating Castable 9-3
9.1.7.2 Class O Insulating Castables 9-3
9.1.8 Air-Setting Plastic Refractory 9-4
9.1.8.1 High-Duty Plastic Refractory 9-4
9. 1.8.2 Super-Duty Plastic Refractory 9-4
9.1.9 Use of Air-Setting Plastic Refractories 9-4
9. 1. 10 Air-Setting Refractory Mortar 9-5
IV
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9.1.11 ASTM Standards 9-5
9.2 General-Refuse Incinerators 9-5
9. 2. 1 Refractories for Walls and Arches 9-6
9. 2. 2 Insulation Requirements 9-6
9.2.3 Exterior Casing 9-7
9.2.4 Floors 9-7
9.2.5 Foundations 9-8
9.2.6 Charging Doors 9-8
9.2.7 Grates 9-8
9.2.8 Air Inlets 9-9
9.2.9 Flues 9-9
9.2.10 Chimneys (Stacks) 9-9
9.2.11 Clearances 9-12
9.2. 12 Incinerator Rooms or Compartments 9-12
9.2.13 Rubbish or Refuse Chutes 9-13
9.2. 14 Chute Terminal Rooms or Bins 9-13
9. 2. 15 Ventilation of Incinerator Rooms 9-13
9. 3 Pathological Incinerators 9-14
10 MISCELLANEOUS RECOMMENDATIONS 10-1
10. 1 Stack Viewer 10-1
10.2 Recommendations For Sampling Ports 10-1
11 OPERATING PROCEDURES H-l
11. 1 General-Refuse Incinerators Without Scrubbers 11-1
11.2 General-Refuse Incinerators With Scrubbers 11-4
11.2. 1 Incinerator Operation 11-4
11.2.2 Scrubber Operation H-4
11.3 Pathological Incinerators Without Scrubbers 11-5
12 THEORETICAL BASIS FOR GENERAL-REFUSE INCINERATOR
DESIGN RECOMMENDATiONS 12-1
12. 1 Principles of Combustion 12-1
12.2 Ignition Chamber Parameters 12-1
12. 3 Mixing and Expansion Chambers 12-5
12.4 Comparison of Retort and In-Line Design Features 12-6
12. 4. 1 Retort Type 12-6
12.4.2 In-Line Type 12-7
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12.4. 3 Comparison of Types 12-7
12.5 Air Supply 12-8
12.6 Draft Control 12-9
12.7 Typical Design Calculations 12-10
12.7.1 General 12-10
12.7.2 Sample Calculations 12-13
13 THEORETICAL, BASIS FOR PATHOLOGICAL INCINERATOR
DESIGN RECOMMENDATIONS 13-1
13. 1 Special Character of Type 4 Waste 13-1
13.2 Design Calculations - General 13-2
13.3 Ignition Chamber Parameters 13-4
13.4 Secondary Combustion Zone Parameters 13-8
13.5 Stack Design 13-9
13.6 Pathological Side Chamber 13-9
13.7 Illustrative Problem 13-9
14 APPENDIX 14-1
14.1 Costs of Incinerators and Scrubbers 14-1
14.2 Additional Information 14-1
15 ACKNOWLEDGMENTS 15-1
16 BIBLIOGRAPHY 16-1
VI
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INTERIM GUIDE OF GOOD PRACTICE
FOR INCINERATION AT FEDERAL FACILITIES
1 INTRODUCTION
Section 111 (a) of the Clean Air Act as amended requires any Federal
department or agency having jurisdiction over any building, installation, or other
property to cooperate with the Department of Health, Education, and Welfare in
preventing and controlling air pollution. In furtherance of this purpose, Presi-
dential_Executive Order 11282 requires establishments of the Executive Branch of
the Government to provide leadership in the nationwide effort to improve the
quality of our air by, among other measures, keeping the emissions of fly ash and
other particulate matter to a, minimum. Acting upon Executive Order 11282 the
Secretary of Health, Education, and Welfare has prescribed standards for imple-
menting these goals and has requested that guides to good practice be issued for
specific operations to aid Federal departments, agencies, and establishments in
the selection of equipment and methods for meeting the standards. This document
is the first such Guide to be issued.
Standards issued as a result of this Executive Order appear as Part 76 in
Subchapter F of Title 42, Code of Federal Regulations. As these Standards apply
to incinerators, they are detailed in Sections 1. 3 and 1. 4 of this Guide.
Requests for guides of good practice, technical material, or consultation
should be directed either to the Chief, Federal Facilities Branch, 'Division of
Abatement, National Air Pollution Control Administration, Public Health Service,
Consumer Protection and Environmental Health Service, Department of Health,
Education, and Welfare, Ballston Center Tower No. 2, 801 North Randolph Street,
Arlington, Virginia 22203, or to the appropriate Regional Air Pollution Control
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Director of the Public Health Service at Department of Health, Education, and
Welfare Regional Offices. (See Table 14-6 for addresses of Regional Directors.)
1.1 PURPOSE OF INTERIM GUIDE OF GOOD PRACTICE
This Interim Guide of Good Practice is to be used by Federal agencies to
select incinerators for burning Types 0, 1, 2, and 4 wastes as defined in Section
3. The information in this Guide applies to incinerators having a burning capacity
of 2000 pounds per hour or less of general refuse and up to 200 pounds per hour
of pathological waste. Advice on burning other types of waste maybe obtained
from the Federal Facilities Branch (See Section 5).
The designs recommended herein are believed to be such as to produce
incinerators that will operate in compliance with the Code of Federal Regulations.
It is not the intent of this Guide to inhibit progress and ingenuity in the develop-
ment of other incinerator designs or methods of waste disposal. For this reason,
specific provisions have been made in Section 5 to allow incinerators of designs
other than those given herein to be approved for use in Federal installations.
In addition, the entire Guide has been designated as an "Interim" Guide until
studies presently being conducted show whether incinerators of other designs,
suitably controlled, can comply with Federal emission standards. When addition-
al designs have been proven capable of meeting Federal emission standards, they
may be included in a subsequent Guide of Good Practice for Incineration at
Federal Facilities.
1.2 APPLICABILITY OF FEDERAL REGULATIONS TO INCINERATORS
The provisions of this Guide apply to Federal Facilities in the 50 states, the
District of Columbia, the Commonwealth of Puerto Rico, the Virgin Islands, Guam,
and American Samoa. However, if state or local emission standards applicable
to incinerators are more strict than those given herein, then the Chief, Federal
Facilities Branch, should be consulted prior to installation of an incinerator of
the designs described in this Guide.
1.2.1 Existing Incinerators
All existing incinerators must comply with the standards set forth in the Code
of Federal Regulations under Title 42, Chapter 1, Subchapter F, Part 76, Section
76. 8, as amended. (See Sections 1. 3 and 1. 4 of this Guide.) Compliance may be
achieved by one or more of the following actions.
1. 2. 1. 1 Modification of Incinerator Usually, modification will be practicable
1 - 2 INCINERATION GUIDE
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only if the changes are relatively minor, such as the addition of bricks to the flame
port, the addition of a secondary burner, or the installation of a barometric dam-
per. If extensive changes in the brickwork are required, the cost and results
usually justify installation of a new incinerator.
1.2. 1.2 Addition of Air Pollution Control Device The most commonly employed
air pollution control device is the low-pressure-drop scrubber. Design specifica-
tions for such a control device that would be suitable for use with incinerator
designs described herein are given in Section 8. When a scrubber is used to up-
grade an existing incinerator, however, it would probably be desirable to use a.
more efficient scrubber than that described herein, inasmuch as the incinerators
described in this Guide will emit less particulate matter than incinerators in need
of upgrading.
1.2. 1.3 Replacement of Incinerator See Sections 6 and 7 of this Guide for
recommendations for new incinerators.
1.2. 1.4 Alternative Method of Refuse Disposal In considering alternatives,
assistance may be sought from the Bureau of Solid Waste Management, Division
of Technical Operations, 12720 Twinbrook Parkway, Rockville, Maryland 20852.
1.2.2 New Incinerators
All new incinerators must comply with the standards set forth in the Code of
Federal Regulations under Title 42, Chapter 1, Subchapter F, Part 76, Section
76. 8, as amended. These standards are given in Sections 1. 3 and 1. 4 of this Guide.
1.3 STANDARDS FOR PARTICULATE EMISSIONS
Particulate emissions shall be measured by the test procedures described in
"Specifications for Incinerator Testing at Federal Facilities" (PHS publication,
October 1967) and any amendments or revisions thereof.
I
1.3.1 Incinerators of Over 200 Pounds per Hour Capacity
Incinerators having burning rates of more than 200 pounds per hour shall not
emit more than 0. 2 grain of particulate matter per standard cubic foot of dry flue
gas corrected to 12 percent carbon dioxide (without the contribution of carbon
dioxide from auxiliary fuel).
1.3.2 Incinerators of 200 Pounds per Hour Capacity and Less
Incinerators having burning rates of 200 pounds per hour or less shall not
emit more than 0. 3 grain of particulate matter per standard cubic foot of dry flue
gas corrected to 12 percent carbon dioxide (without the contribution of carbon
Introduction 1-3
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dioxide from auxiliary fuel).
1.4 STANDARDS FOR VISIBLE EMISSIONS
1.4.1 Incinerators Acquired On or After June 3, 1966
For incinerators acquired on or after June 3, 1966, the density of any emis-
sion to the atmosphere shall not exceed number 1 on the Ringelmann Scale or the
Smoke Inspection Guide for a period or periods aggregating more than 3 minutes
in any 1 hour, or be of such opacity as to obscure an observer's view to an equiva-
lent degree.
The Ringelmann chart should be used in accordance with the Procedures in
the Bureau of Mines Information Circular No. 8333. The Smoke Inspection Guide
should be used in accordance with procedures in Title 42, Chapter 1, Subchapter
F, Section 75.2 of the Code of Federal Regulations.
1.4.2 Incinerators Acquired Prior to June 3, 1966
For incinerators acquired prior to June 3, 1966, the density of any emission
to the atmosphere shall not exceed number 2 on the Ringelmann Scale or the Smoke
Inspection Guide for a period or periods aggregating more than 3 minutes in any 1
hour or be of such opacity as to obscure an observer's view to an equivalent degree.
1.5 CONSIDERATIONS FOR GOOD PLANNING OTHER THAN INCINERATOR DESIGN
In addition to the design of the incinerator itself, careful consideration must
be given to the following items when installation of an incinerator is being planned:
1. Collection and method of charging the refuse.
2. Ample areas around the incinerator for charging, stoking, ash handling
and general maintenance.
3. Adequate air supply to the incinerator room at the stoking and charging
levels.
4. Effect of air conditioning and ventilating equipment on the air supply or
the draft available from the draft-producing equipment.
5. Adequate draft (negative pressure) to handle all theoretical and excess air
required to assure safe operation and complete combustion at reasonable
temperatures.
6. Location of the top of the chimney or stack with respect to ventilation
intakes, penthouses, or other obstructions.
1-4 INCINERATION GUIDE
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2 DEFINITIONS OF INCINERATOR TERMS
Air Supply
All air supplied to the incinerator equipment for combustion, ventilation,
and cooling. Standard air is air at standard temperature and pressure, namely,
70°F and 29. 92 inches of mercury.
1. Air Jets Streams of high-velocity air issuing from nozzles in the incin-
erator enclosure to provide turbulence. The air jets, depending on their
location, maybe used to provide excess, primary, secondary, or over-
fire air.
2. Excess Air The air remaining after a fuel has been completely burned,
or the air supplied in addition to the theoretical quantity.
3. Over fire Air Any air, controlled with respect to quantity and direction,
supplied beyond the fuel bed, as through ports in the walls of the primary
combustion chamber, for the purpose of completing combustion of com-
bustible materials in the gases from the fuel bed or reducing operating
temperatures within the incinerator.
4. Primary Air Any air, controlled with respect to quantity and direction,
forced or induced, supplied through or adjacent to the fuel bed, to promote
combustion of the combustible materials in the fuel bed.
5. Secondary Air Any air, controlled with respect to quantity and direction,
supplied beyond the fuel bed, as through ports in the walls or bridge wall
of the primary combustion chamber (overfire air), or the secondary com-
bustion chamber, to cpmplete combustion of combustible materials in the
gases from the fuel bed or to reduce operating temperature within the
incinerator.
6. Theoretical Air The stoichiometric amount of air required for complete
combustion of a given quantity of a specific fuel.
7. Underfire Air - Any air, controlled with respect to quantity and direction,
forced or induced, supplied beneath the grate, that passes through the
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fuel bed.
Auxiliary-Fuel Firing Equipment
Equipment to supply additional heat, by the combustion of an auxiliary fuel, for
the purpose of attaining temperatures sufficiently high (1) to dry and ignite the
waste material; (2) to maintain ignition thereof; and (3) to effect complete combus-
tion of combustible solids, vapors, and gases.
Baffle
Any refractory construction intended to change the direction of flow of the products
of combustion.
Breeching or Flue Connection
The connection between the incinerator and auxiliary equipment, between the incin-
erator and stack or chimney, or between auxiliary equipment and stack or chimney.
Bridge Wall
A partition wall between chambers over which products of combustion pass.
British Thermal Unit
The quantity of heat required to raise 1 pound of water 1° Fahrenheit, abbreviated
Btu and B. T. U.
Burner
A device for the introduction of a flame by delivering fuel and its combustion air,
at desired velocities and turbulence, to establish and maintain proper ignition and
combustion of the fuel.
1. Afterburner A burner installed in the secondary combustion chamber or
in chambers separated from the incinerator proper. (Also referred to as
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Burning Rate
The amount of waste incinerated per unit of time, usually expressed in pounds per
hour.
Bypass
An arrangement of breechings or flue connections and dampers to permit the
alternate use of two or more pieces of equipment by directing or diverting the
flow of the products of combustion.
Capacity
The amount of waste stipulated as the incineration rate for specific types of refuse,
expressed in pounds per hour.
Charging Chute
A passage through which waste materials are conveyed from above to the primary
combustion chamber.
Charging Door
A closure for the primary chamber loading entrance.
Checkerwork
A pattern of multiple openings in refractory structures through which the pro-
ducts of combustion pass to promote turbulent mixing of the gases.
Chimney, Stack, Flue
A passage for conducting products of combustion to the atmosphere.
Clinker
Hard sintered or fused material, formed in the fire by the agglomeration of resid-
ual ash, metals, glass, and ceramic material.
Combustion Chamber, Expansion Chamber, Settling Chamber
Any chamber designed to reduce the velocity of the products of combustion to
promote the settling of fly ash from the gas stream and to allow space and time
to complete combustion.
Curtain Wall
A partition wall between chambers, which serves to deflect gases in a downward
direction. (Also referred to as a drop arch.)
Damper
A manually or automatically controlled device to regulate draft or the rate of
flow of air or combustion gases.
Definitions of Incinerator Terms 2-3
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1. Barometric Damper - A hinged or pivoted valve placed and adjusted by
counterbalancing so as to admit air to the breeching, flue connection, or
stack to maintain automatically the required draft in the incinerator.
2. Butterfly Damper - A throttling disk or valve that rotates on its hinged
axis to control airflow in a duct, breeching, flue connection, or stack.
3. Guillotine Damper - An adjustable, counterbalanced blade installed in a
breeching or flue connection and arranged to move vertically across the
breeching or flue connection.
4. Sliding Damper - An adjustable blade installed in a. duct, breeching, flue
connection, or stack and arranged to move horizontally across the duct,
breeching, flue connection or stack.
Down Pass
Chamber or passage between two chambers that carries the products of combustion
in a downward direction,
Draft
The pressure difference between the incinerator or any component part and the
atmosphere, that causes a continuous flow of air and products of combustion
through the gas passage of the incinerator to the atmosphere.
1. Forced Draft The pressure difference created by the action of a fan,
blower, or ejector to supply primary combustion air greater than
atmospheric pressure.
2. Induced Draft - The pressure difference created by the action of a fan,
blower, or ejector installed between the incinerator and the stack, or at
the stack exit.
3. Natural Draft - The pressure difference created by stack or chimney
because of its height and the temperature difference between the flue
gases and the atmosphere.
Dust Loading
The amount of fly ash carried in the products of combustion, usually expressed in
grains per standard cubic foot at 12 percent carbon dioxide, without the contribu-
tion of carbon dioxide from the burning of auxiliary fuel.
Effluent
The flue gas or products of combustion that reach the atmosphere from the burning
process.
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Expansion Chamber, Combustion Chamber, Settling Chamber
See definition under Combustion Chamber, Expansion Chamber, Settling Chamber.
Flame Port
A small port in the parting wall through which the flames and products of com-
bustion from the burning refuse must pass.
Flue Gas
All gases leaving the incinerator by way of the flue, including gaseous products
of combustion, water vapor, excess air, and nitrogen.
Fly Ash
Suspended ash particles, charred paper, dust, soot, and other partially inciner-
ated matter carried in the products of combustion. (Also referred to as particu-
late matter or pollutant. )
Fly Ash Collector
Auxiliary equipment designed to remove fly ash in dry form from the products of
combustion.
Gas Washer or Scrubber
Equipment for removing fly ash and other objectionable materials from, the pro-
ducts of combustion by means of water sprays or wetted baffles.
Grate
Surface that supports waste material, but with suitable openings to permit passage
of air through the burning waste. It is usually located in the primary combustion
chamber and is designed to permit removal of ash and unburned residue. Grates
maybe horizontal or inclined, stationary or movable.
Hearth
A solid surface on which waste material with high moisture content, or waste
material that may turn to liquid before burning, is placed for drying or burning.
1. Cold Hearth A surface on which waste material is dried and/or burned
by the action of hot combustion gases that pass only over the waste material.
2. Hot Hearth A heated surface on which waste material is dried and/or
burned by the action of hot combustion gases that pass first over the waste
materials and then under the hearth.
Definitions of Incinerator Terms 2 -5
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Heating Value
The heat released by combustion of a unit quantity of waste or fuel, measured in
British Thermal Units (Btu). In this Guide heating value is on an as-fired basis
for refuse and on the higher or gross heating value for fuel.
Heat Release Rate
The amount of heat liberated during the process of complete combustion and ex-
pressed in Btu per hour per cubic foot of the internal furnace volume in which
such combustion takes place.
Ignition Chamber, Primary Chamber
The chamber of the incinerator in which refuse is burned.
Incineration
The process of igniting and burning solid, semisolid, liquid, or gaseous com-
bustible waste to carbon dioxide and water vapor.
Incinerator
An engineered apparatus capable of withstanding heat and designed to efficiently
reduce solid, semisolid, liquid, or gaseous waste by combustion at specified
rates, to residues containing little or no combustible material. As used herein,
a general-refuse incinerator is a multiple-chamber incinerator designed primarily
for burning waste of Types 0, 1, and 2 at rates of from 50 to 2000 pounds per
hour. A pathological incinerator is a. multiple-chamber incinerator designed to
burn 200 pounds per hour or less of Type 4 waste.
Mixing Chamber
A chamber usually placed between the primary combustion chamber and an ex-
pansion chamber wherein thorough mixing of the products of combustion is accom-
plished by turbulence created by increased velocities of gases, checkerwork,
and/or changes in direction of the gas flow.
Multiple-Chamber Incinerator
A multiple-chamber incinerator is any article, machine, equipment, contrivance,
structure, or part of a structure consisting of three or more refractory-lined
combustion chambers in series, physically separated by refractory walls and in-
terconnected by gas passage ports or ducts that is used to dispose of waste ma-
terial by burning.
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Particulates or Particulate Matter
Suspended ash particles, charred paper, dust, soot, and other partially inciner-
ated matter carried in the products of combustion. (Also referred to as fly ash. )
For the purposes of determining compliance with Section 76. 8, Title 42 of the
Code of Federal Regulations, particulate matter is defined as any material, ex-
cept uncombined water, which is suspended in a gas stream as a liquid or solid
at standard conditions.
Parting Wall
In retort incinerators, the parting wall separates the primary chamber from
both a secondary chamber and an expansion chamber.
Primary Chamber, Ignition Chamber
See definition under Ignition Chamber, Primary Chamber.
Settling Chamber, Expansion Chamber, Combustion Chamber
See definition under Combustion Chamber, Expansion Chamber, Settling Chamber.
Side Chamber
A small chamber used for burning pathological waste that is built into the side of
a general-refuse burner.
Spark Arrester
A screen-like device that prevents sparks, embers, and other ignited materials
larger than a given size from being expelled to the atmosphere.
Standard Conditions
Standard conditions are a gas temperature of 70° Fahrenheit and a gas pressure
of 14. 7 pounds per square inch, absolute. Results of all analyses and tests should
be calculated or reported at this gas temperature and pressure.
Definitions of Incinerator Terms
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3 WASTE CLASSIFICATIONS
Type 0
A mixture of highly combustible waste such as paper, cardboard cartons,
wood boxes, and floor sweepings from commercial and industrial activities.
The mixture contains up to 10 percent by weight of plastic bags, coated paper,
laminated paper, treated corrugated cardboard, oily rags, and plastic or
rubber scraps.
This type of waste contains 10 percent moisture and 5 percent noncom-
bustible solids, and has a heating value of 8, 500 Btu per pound as fired.
Type 1
A mixture of combustible waste such as paper, cardboard cartons, wood
scrap, foliage, and floor sweepings from domestic, commercial, and industrial
activities. The mixture contains up to 20 percent by weight of restaurant waste,
but contains little or no treated paper, plastic, or rubber wastes.
This type of waste contains 25 percent moisture and 10 percent incom-
bustible solids, and has a heating value of 6, 500 Btu per pound as fired.
Type 2
An approximately even mixture of rubbish and garbage by weight
This type of waste, common to apartment and residential occupancy, consists
of up to 50 percent moisture and 7 percent incombustible solids, and has a heat-
ing value of 4, 300 Btu per pound as fired.
Type 3
Garbage such as animal and vegetable wastes from restaurants, hotels,
hospitals, markets, and similar installations.
This type of waste contains up to 70 percent moisture and up to 5 percent in-
combustible solids, and has a heating value of 2, 500 Btu per pound as fired.
Type 4
Human and animal remains, such as organs, carcasses, and solid organic
wastes from hospitals, laboratories, slaughterhouses, animal pounds, and
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similar sources, consisting of up to 85 percent moisture and 5 percent incom-
bustible solids, and having a heating value as low as 1, 000 Btu per pound as fired.
Type 5
Gaseous, liquid, or semiliquid by-product waste, such as tar, paint, sol-
vent, sludge, and fumes from industrial operations. Btu values must be deter-
mined by the individual materials to be destroyed.
Type 6
Solid by-product waste, such as rubber, plastic, and wood waste from
industrial operations. Btu values must be determined by the individual materials
to be destroyed.
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4 RECOMMENDED INCINERATOR AND GAS WASHER DESIGNS
The incinerator designs described herein are recommended for use in
Federal facilities. The incinerator designs given in Sections 6 and 12 are recom-
mended for incinerators that are to burn up to 2, 000 pounds per hour of Types 0,
1, and 2 waste. The designs set forth in Sections 7 and 13 are recommended for
incinerators that will burn up to 200 pounds per hour of Type 4 •waste.
Incinerators of the design given in this Guide have been tested and found to
meet the Code of Federal Regulations for incinerators with capacities of 200
pounds per hour or less. An incinerator of more than 200 pounds per hour capa-
city must be equipped with scrubbers of the types described in Section 8, or with
scrubbers of equivalent efficiency, to meet the stricter limits of the Code of
Federal Regulations applicable to the larger incinerator sizes (see Section 1.3 of
this Guide), unless the unit by itself can be shown to meet the limits of the Code.
Incinerators and incinerator-washer combinations built as recommended
herein will be considered to be in compliance with the Code of Federal Regulations.
Testing will not be required for such units.
See Section 5 for information about obtaining approval for incinerators and
gas washers of designs other than those recommended herein.
Multiple-chamber incinerators designed to burn general refuse or pathologi-
cal waste that conform to Incinerator Institute of America (IIA) Standards will be
accepted as alternate incinerators when such incinerators are tested according to
Section 14 and meet the emission standards of Section 1. Any gas washers employ-
ed should meet the requirements of Section 8.
4-1
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5 ALTERNATE INCINERATOR AND GAS WASHER DESIGNS
The Federal Facilities Branch, Division of Abatement, National Air Pollution
Control Administration, Arlington, Va. 22203, or the appropriate Regional Air
Pollution Control Director located in a Department of Health, Education, and
Welfare Regional Office (see Table 14. 6) may be consulted for information and
assistance in regard to:
1. Modifying existing incinerators.
2. Installing incinerators of the following types:
a. Incinerators for burning waste that is 100 percent garbage.
b. Incinerators for burning more than 200 pounds per hour of human and
animal remains.
c. Incinerators for burning wood, plastic, and organic liquids.
d. Incinerators for burning Types 0, 1, 2, and 4 waste (in amounts of
over 200 pounds per hour), the designs of which are other than
those specified in this Guide.
3. Testing incinerators.
Before incinerators not of the designs specified herein, including upgraded
units, are accepted, they must meet the Federal emission limits as given in
Sections 1. 3 and 1. 4. To show compliance, a testing organization may conduct
tests provided the organization (hereafter called tester) has had experience in
testing incinerators or can establish competency to conduct tests. Either the
Federal Facilities Branch or the appropriate Regional Air Pollution Control Direc-
tor may be consulted for assistance in choosing a tester. The Federal Facilities
Branch should be notified 1 month in advance of any acceptance test to allow an
observer to attend. Test procedures used shall be those described in "Specifica-
tions for Incinerator Testing at Federal Facilities" (PHS Publication, October,
1967) and any amendments or revisions thereof. Said document is available from
the Federal Facilities Branch.
In addition to meeting all emission standards, incinerator systems must, in
5-1
-------
the judgment of the Federal Facilities Branch, be constructed of refractories,
insulation, and other materials equivalent in resistivity and quality to the construc-
tion standards recommended in Section 9.
Once an incinerator system has been found to meet all applicable construc-
tion and emission standards, all other systems of an essentially identical design
will be acceptable in Federal Facilities.
5-2 INCINERATION GUIDE
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6 DESIGN RECOMMENDATIONS FOR GENERAL-REFUSE INCINERATORS
6.1 BASIS FOR DESIGN RECOMMENDATIONS
Tests on incinerators designed according to these recommended standards
have shown that when properly operated, the incinerators can meet, without the use
of scrubbers, the applicable Federal emission standards for incinerators with rated
burning capacity of 200 pounds per hour or less. At capacities of more than 200
pounds per hour, incinerators should be equipped with scrubbers to ensure that
applicable Federal emission limits are met.
6.2 TYPES OF GENERAL-REFUSE INCINERATORS
Multiple-chamber incinerators are of two general types. Figure 6-1 illus-
trates the retort type, named for the return flow of gases through the "U" arrange-
ment of the component chambers; and Figure 6-2 shows the in-line type, so called
because the three chambers follow one another in a line.
6. 2. 1 Multiple-Chamber Retort Incinerators
The following guidelines are recommended:
1. That general-refuse retort incinerators installed in Federal facilities
have the configuration shown in Figure 6-3.
2. That retort incinerators with rated capacities of over 1, 000 pounds per
hour not be built.
3. That incinerators of over 200 pounds per hour rated capacity be equipped
with gas washers as specified in Section 8 of this Guide, or equivalent
gas washers as determined by the Federal Facilities Section.
4. That the actual dimensions of incinerators shown in Figures 6-1 and
6-3 be established by using the design considerations given in Section
12 of this Guide.
6.2.2 Multiple-Chamber In-L/ine Incinerators
The following guidelines are recommended:
1. That all in-line incinerators installed in Federal facilities for the pur-
pose of burning wastes of Types 0, 1, or 2 have the configuration shown
in Figure 6-4.
6-1
-------
IGNITION CHAMBER
SECONDARY AIR PORT
FLAME PORT / MIXING CHAMBER
CHARGING
DOOR
.CURTAIN WALL
COMBUSTION
CHAMBER
Figure 6-1- Cutaway drawing of multiple-chamber retort incinerator.
2. That in-line incinerators with a rated burning capacity of less than 750
pounds per hour not be built.
3. That all in-line incinerators be equipped with gas washers as specified
in Section 8 of this Guide, or equivalent gas washers, as determined by
the Federal Facilities Branch.
4. That the actual dimensions of incinerators shown in Figures 6-2 and 6-4
be established by using the design considerations in Section 12 of this
Guide.
6.3 RECOMMENDATIONS FOR AUXILIARY GAS BURNERS
6. 3. 1 Incinerators Requiring Burners
Secondary burners alone need be installed on incinerators that are to be used
solely to burn Type 0 waste. If the incinerator is to burn wastes of Types 1, 2, 3,
or 4, both primary and secondary burners should be installed. The need for
6-2
INCINERATION GUIDE
-------
IGNITION CHAMBER
SECONDARY AIR PORT
FLAME PORT \ CURTAIN WALL COMBUSTION CHAMBER
MIXING CHAMBER
BREECHING
CHARGING
DOOR
Figure 6-2- Cutaway drawing of multiple-chamber in-line incinerator.
burners in incinerating other types of waste is dictated by the nature of the waste
itself.
6. 3. 2 Types of Natural Gas Burners Recommended
Incinerators having a capacity of less than 200 pounds per hour that use
burners rated at less than 400, 000 Btu per hour may be of either the atmospheric
or power-burner type. In either case, a continuously or intermittently burning
stable pilot adequate to ensure safe, reliable ignition should be installed. A flame
safeguard should be used so that no gas can flow to the main burner unless satisfac-
tory ignition is assured. The response time of this flame safeguard to de-energize
the gas shutoff device on flame failure should not exceed 180 seconds.
Auxiliary burners on incinerators with ratings of 200 pounds per hour or
more, i.e. , those equipped with a fan and scrubber, should be of the power-burner
type, because this type of burner usually retains its flame better when a fan is
used to induce draft. For burners with ratings of more than 400, 000 Btu per hour
input, the burner equipment shall be of the power type that utilizes a forced-draft
Design Recommendations for General - Refuse Incinerators
6-3
-------
xxxxxxxxxxxxxxxxxx?
'////•//•/////////////77s
PLAN VIEW
1 STACK
2 SECONDARY AIR PORT
3 PRIMARY GAS BURNER
4 ASH PIT CLEANOUT DOOR
5 GRATES
6 CHARGING DOOR
7 FLAME PORT
8 UNDERFIRE AIR PORT
9 IGNITION CHAMBER
10 OVERFIRE AIR PORT
11 MIXING CHAMBER
12 COMBUSTION CHAMBER
13 CLEANOUT DOOR
14 CURTAIN WALL PORT
15 SECONDARY GAS BURNER
SIDE ELEVATION
END ELEVATION (\4)
Figure 6-3. Recommended plan for multiple-chamber retort incinerators.
blower to supply air needed for combustion under controlled conditions. A contin-
uously or intermittently burning pilot should be used to ensure safe and reliable
ignition. Automatic spark ignition should be used on pilots for burners with input
of more than 1, 000, 000 Btu per hour. A suitable flame safeguard should be used so
that no gas can flow to the main burner unless satisfactory ignition is assured. On
burners with inputs of from 400, 000 to 1, 000, 000 Btu per hour, the response time
of the flame safeguard to de-energize the gas shutoff device on flame failure should
not exceed 180 seconds. In capacities of more than 1, 000, 000 Btu per hour, the
response time of the aforementioned flame safeguard should not exceed 4 seconds.
The burner assembly should consist of the main burner, pilot burner, auto-
matic valve, the necessary manual valves, and accessory equipment, plus inter-
connecting pipes and fittings with provision for rigid mounting. The burner should
be constructed so that parts cannot be incorrectly located or incorrectly fitted
together. Power burners sealed to the walls of incinerators with capacities of
6-4
INCINERATION GUIDE
-------
PLAN VIEW
© ©
SIDE ELEVATION
©
1 STACK 6 FLAME PORT 11 CLEANOUT DOORS
2 SECONDARY AIR PORTS 7 IGNITION CHAMBER 12 UNDERFI RE Al R PORTS
3 ASH PIT CLEANOUT DOORS 8 OVERFIRE AIR PORTS 13 CURTAIN WALL PORT
4 GRATES 9 MIXING CHAMBER 14 PRIMARY GAS BURNERS
5 CHARGING DOOR 10 COMBUSTION CHAMBER 15 SECONDARY GAS BURNERS
Figure 6-4. Recommended plan for multiple-chamber in-line incinerators.
more than 100, 000 Btu per hour must be supplied with a means of proving air
supply before the main gas valve can be energized.
Electrical motors of more than 1/12 horsepower on power burner equipment
should be designed for continuous duty and should be provided with thermal over-
load protection or current-sensitive devices.
When a complete automatic pilot shutoff system is utilized, the controls
should be readily accessible and arranged so that the main burner gas can be
Desip Recommendations for General-Refuse Incinerators
6-5
-------
manually shut off during lighting of the pilot. When a complete automatic pilot
system is not utilized, a readily accessible, manually operated, quarter-turn,
lever-handle, plug-type valve should be provided to shut off or turn on the gas
supply to the main burner manifold. This valve should be upstream from all con-
trols except the pilot control valve.
Clearly defined and complete instructions for lighting and shutting down the
burner should be provided in durable, weatherproof material for posting in a. posi-
tion where they can be read easily.
6.3.3 Sizes of Burners Recommended •
Where auxiliary burners are used, their capacity range should include the
values shown in Table 6-1.
Table 6-1. GAS BURNER RECOMMENDATIONS FOR GENERAL-
REFUSE INCINERATORS
Size of burners, 10^ Btu/hr
Capacity of
incinerator,
Ib/hr
50
100
150
£50
500
750
1000
1500
2000
Primary burners
Type l
refuse
150
200
250
300
550
750
900
1100
1600
Type 2
refuse
250
550
650
750
1100
1500
1700
2200
3300
Secondary burners
All refuse
200
300
400
650
1000
1300
1700
2100
2700
6'. 3. 4 Other Fuels
If natural gas is not available, equivalent amounts of liquid fuels may be
used. Fuel oils of grades higher than Number 2, however, should not be used.
The National Fire Protection Association Standard No. 31, Installation of Oil
Burning Equipment (1965), should be adhered to where oil burners are used.
If liquified petroleum gas is used, burners should be equipped with a device
i
that will automatically shut off the main gas supply in the event the means of
ignition becomes inoperative. The arrangement should be such as to shut off the
fuel supply to the pilot burner also.
6-6
INCINERATION GUIDE
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7 DESIGN RECOMMENDATIONS FOR PATHOLOGICAL INCINERATORS
7.1 BASIS FOR DESIGN RECOMMENDATIONS
Tests have shown that when properly operated, incinerators of the design
recommended herein can meet the applicable Federal emission standards in sizes
of 200 pounds per hour or less rated burning capacity.
Because the tests do not at present extend beyond incinerators having a
burning capacity in excess of 200 pounds per hour, the specifications given herein
apply only to incinerators having a lesser burning rate. Assistance in the design
of larger incinerators of this class may be obtained from the Federal Facilities
Branch, Division of Abatement, National Air Pollution Control Administration.
7.2 MULTIPLE-CHAMBER PATHOLOGICAL INCINERATORS - GENERAL
The pathological incinerators specified in this Guide are of one configuration,
that of a retort incinerator, as shown in Figure 7-1. To be heated before entering
the expansion chamber, gases from the mixing chamber pass under the hearth.
This flow pattern holds for sizes of 100 pounds per hour and greater. For smaller
sizes, a hot hearth and underhearth ports are not required, and the gases pass, as
in a conventional retort incinerator, directly from the mixing chamber into the
expansion chamber. Additional basic design information on these incinerators may
be found in Section 13.
Small amounts of Type 4 waste may be burned in a chamber built on the side
of a general-refuse incinerator. An incinerator with such a side chamber is
shown in Figure 7-2.
7.2.1 Pathological Retort Incinerators
The following guidelines are recommended:
1. That all pathological incinerators with rated burning capacities of less
than 200 pounds per hour built in Federal facilities have the configuration
shown in Figure 7-3.
2. That pathological incinerators of 200 pounds per hour burning capacity
or less have no scrubbers.
3. That the design considerations given in Section 13 of this Guide be used to
7-1
-------
UNDER
HEARTH
CHAMBER
Figure 7-1. Multiple-chamber pathological incinerator.
establish dimensions for pathological incinerators in keeping with the
configuration shown in Figure 7-3.
4. Assistance in the design of incinerators of larger capacity should be
obtained from the Federal Facilities Branch, Division of Abatement.
7.2.2 Side Chamber for Pathological Refuse
1. Side chambers should be used only when small amounts of waste rela-
tive to the main capacity of the larger incinerator are to be burned. A
drawing of a typical side chamber is shown in Figure 7-4.
2. Design information on side chambers maybe found in Section 13.
7-2
INCINERATION GUIDE
-------
Figure 7-2. Multiple-chamber incinerator with pathological retort.
Design Recommendations for Pathological Incinerators
7-3
-------
1 STACK
2 SECONDARY AIR PORT
3 GAS BURNERS
4 UNDERHEARTH CHAMBER
5 REFRACTORY HEARTH
6 CHARGING DOOR
7 FLAME PORT
8 UNDERHEARTH PORT
9 IGNITION CHAMBER
10 OVERFIRE AIR PORT
11 MIXING CHAMBER
12 COMBUSTION CHAMBER
13 CLEANOUT DOOR
14 CURTAIN WALL PORT
PLAN VIEW
SIDE ELEVATION
r
Figure 7-3. Recommended plan for pathological incinerators.
7-4
INCINERATION GUIDE
-------
FLAME PORT CHARGING DOOR
GAS BURNER
SIDE ELEVATION
END ELEVATION
Figure 7-4. Side chamber for pathological refuse.
Design Recommendations for Pathological Incinerators
7-5
-------
8 DESIGN RECOMMENDATIONS FOR INCINERATOR SCRUBBERS
A specific scrubber design is recommended herein, but other designs may
be used if they are of an efficiency equal to that of the recommended design and
are constructed of materials of equivalent resistivity to corrosion, heat, and other
applicable stresses.
8.1 GENERAL
Effluents from general-refuse incinerators burning more than 200 pounds per
hour should be cleaned in scrubbers to meet the particulate limit requirement.
Since this will generally mean that scrubbers will be widely employed, the dis-
advantages associated with their use should be recognized.
When scrubbers are used, power lines may have to be installed to furnish
energy to operate the induced-draft fan and water pump. Provisions must also be
made to supply scrubbing water and a means of disposing of contaminated water
from the scrubber. In some areas it will also be necessary to adjust the pH and
process the contaminated water through a clarifier to remove fly ash and other
collected solids before the water is sewered.
A scrubber may require considerable maintenance as a result of corrosion
caused by the acidic water continuously flowing from it. Scrubber water is seldom
recirculated because this increases its acidity and, therefore, the rate of corrosion.
Even when scrubbers are lined with dense refractory material, corrosion of the
steel casing may ultimately occur. In addition, there maybe noticeable corrosion
and erosion of the fan impeller and, to some lesser degree, of the fan housing.
The continuous contact of the acidic water in the sump of the scrubber may grad-
ually attack this surface.
8.2 SCRUBBER DESIGN PARAMETERS
Several basic factors are considered in designing scrubbers. To satisfac-
torily collect the fly ash, the water-gas mixture must be retained within the
scrubber for 1 to 1-1/2 seconds at gas velocities not exceeding 15 feet per second.
The residence time in the scrubber should also be sufficient to vaporize all the
8-1
-------
water droplets within the effluent gas stream. Complete vaporization is important
since nuisance complaints may result from the carryover of water droplets de-
posited on the surrounding area. From an appearance standpoint, the scrubber
should not be longer or higher than the incinerator. The scrubber width should be
limited to allow the scrubber to be easily located either adjacent to or at the rear
of any incinerator of the retort type. The usual location for scrubbers serving
the in-line type incinerator is at the rear of the combustion chamber. Placing
the scrubber adjacent to the final combustion chamber is also feasible.
Air dilution of the gases from the incinerator prior to entering the scrubber
is unnecessary. Water is introduced into the effluent as it enters the scrubber
and flows concurrently down its first pass. By immediately introducing the water
into the gas stream, the water has a longer period to mix and evaporate, which
accomplish the desired cooling. The average velocity of the gas-water
mixture in the first pass ranges from 9 to 10 feet per second. The velocity of the
gases in the upward pass is determined by calculating the remaining time require-
ment so that the gases are within the scrubber for a total time of approximately
1-1/4 seconds. The curtain wall port is sized to permit an air velocity range of
18 to 20 feet per second to prevent excessive pressure drop from occurring and to
prevent water from the sump from being re-entrained in the effluent. The gases
exit from the extreme top of the uppass so that its full length can be used for the
evaporation of any remaining water in the gas stream. This location of the exit at
the top also prevents water traveling up the back side of the scrubber from
becoming re-entrained in the gas stream. Another feature that reduces re-entrain-
ment of water droplets is a. 4-inch channel at the bottom of the curtain wall. The
channel collects the larger droplets and carries the water across the width of the
scrubber, down its side walls, and into the sump below. Additional structural
support for the refractory of the dividing wall is also provided by this channel.
Water in the base of the scrubber collects fly ash and other materials re-
moved from the gas stream may be easily deposited and retained. The water
depth is maintained at approximately 3 inches by extending the end of the overflow
pipe 3 inches above the floor of the scrubber. Another drain pipe should be in-
stalled at floor level so that fly ash and other solids can be washed down the sipping
floor of the scrubber.
Design parameters recommended are as follows:
8-2 INCINERATION GUIDE
-------
1. The water rate to the scrubber should be 1 gallon per minute for every
100 pounds per hour of rated capacity of the incinerator. This gives a
water-to-gas ratio of 1 gallon per minute for every 400 standard cubic
feet of effluent stack gas.
2. Configuration of scrubbers for retort and in-line incinerators are given
in Figures 8-1 and 8-2, respectively. A graph showing internal areas
of the various ports in scrubbers versus incinerator size is given in
Figure 8-3.
1 SPRAY NOZZLES
2 ACCESS DOOR
3 CASTABLE REFRACTORY
4 DOWN-PASS
5 CHANNEL
6 OVERFLOW
7 WATER LEVEL
8 INDUCED DRAFT FAN
9 UP-PASS
10 DRAIN
SIDE ELEVATION
NOTES:
CASTABLE REFRACTORY - 135 Ib/ft.3
EXTERIOR STEEL - 3/16 in. PLATE.
NOZZLES - STAINLESS STEEL.
FAN - 600° F RATING.
CHANNEL - 4 in.
FLOOR - 4-degree SLOPE TO DRAIN.
+ FOUR NOZZLES ON '0' DIMENSION DIAMETER
FOR SIZES 500 TO 1000 Ib/hr.
'ONE NOZZLE FOR INCINERATOR SIZES 50
TO 250 Ib/hr.
Figure 8-1. Design recommendations for retort incinerator scrubbers.
Design Recommendations for Incinerator Scrubbers
5-3
-------
°0
1 ACCESS DOOR
2 PRIMARY SPRAYS
3 SECONDARY SPRAYS
4 CASTABLE REFRACTORY
5 DOWN-PASS
6 EFFLUENT INLET
7 INDUCED DRAFT FAN
8 WATER LEVEL
9 OVERFLOW
10 UP-PASS
11 CHANNEL
12 DRAIN
PLAN VIEW
NOTES:
CASTABLE REFRACTORY - 135 Ib/ft.3
EXTERIOR STEEL - 3/16 in. PLATE.
NOZZLES - STAINLESS STEEL.
FAN - 600° F RATING.
CHANNEL - 4 in.
FLOOR - 4-degree SLOPE TO DRAIN.
•ALL SPRAY NOZZLES TO BE EQUALLY
SPACED WITHIN THE N DIMENSION
Figure 8-2. Design recommendations for in-line incinerator scrubbers.
8.3 SCRUBBER CONTROLS
While it is recommended that the scrubber controls described herein be in-
stalled, it should be realized that a special maintenance and testing program must
be established to keep the control systems in good operating condition.
Many types of automatic controls are used to regulate the temperature of
the gases leaving the scrubber. Satisfactory controls, which have proved to be
both simple and economical, consist of a hand-operated control valve and two
automatic solenoid valves. The hand-operated valve is installed in parallel with
the solenoid valves between the water supply and the nozzles.
8-4
INCINERATION GUIDE
-------
10,000
1,000
<
UJ
o:
o
u
g
u
INSIDE HEIGHT
(IN INCHES)
1,000
2,000
SIZE OF INCINERATOR, Ib/hr
Figure 8-3. Internal sizing of scrubbers.
The solenoid valves are electrically connected so that one opens when the
fan is placed in operation. The flow of water through this valve is adjusted to
approximately 40 percent of the scrubber needs. The other valve is controlled by
a thermocouple located at the fan inlet. When the temperature at the fan inlet
reaches 220°F, the second solenoid valve opens and the remainder of the water
Design Recommendations for Incinerator Scrubbers
8-5
-------
is delivered to the nozzles. This arrangement is used to keep the temperature
of the gases from exceeding 350°F. Should the automatic control system fail,
the operator may open the hand valve and furnish sufficient water to the scrubber.
A back-up system also may be installed to prevent heat damage to the fan in
case the automatic system just described fails. One such system frequently used
consists of a thermocouple located at the fan inlets and additional solenoid-valve -
controlled nozzles located in either the downpass or the uppass of the scrubber.
The nozzles should be capable of supplying at least the same quantity of water as
the combined volume of the primary and secondary sprays. Should the temperature
at the fan inlet exceed 500°F, the back-up solenoid valve opens, and the full volume
of water flows to the nozzles to cool the effluent to an acceptable level. As a final
precaution, a warning alarm, actuated at 550°F, by a thermocouple at the fan
inlet, may be installed to alert the operator to excessive temperature increases.
Back-up systems must be tested frequently so that they are operable when
the need arises. Consequently, a safety system of this type would be of doubtful
value unless a regular maintenance and testing program were established. .
8.4 SCRUBBER CONSTRUCTION
The steel exterior of the scrubber should be constructed of 3/16-inch-thick
steel plate. Hangers should be mounted on the walls and top of the scrubber on
9-inch centers to hold the lining firmly to the walls. Linings of 135-pound-per-
cubic-foot castable refractory should be 3 inches thick for incinerators with capa-
cities of 750 pounds per hour or less. Units with capacities in excess of 750
pounds per hour should utilize 4-inch linings. The castable refractory floor should
be sloped upward from the center of the scrubber at a 4-degree angle to facilitate
the removal of collected fly ash and solids. The primary spray nozzles should be
of the flat-spray type so that water droplets do not enter the connecting breeching
and damage the refractory in the final combustion chamber of the incinerator. The
secondary nozzles should be of the full cone type with a discharge angle of approxi-
mately 60 degrees. Nozzles mounted within the inlet duct should be provided with
an access opening for cleaning or replacement. Nozzles mounted in the top of the
unit should be installed out of the hot gas stream and should be removable from
the exterior of the scrubber. Nozzles should be constructed of brass or stainless
steel.
8-6 INCINERATION GUIDE
-------
8.5 INDUCED-DRAFT FAN
8. 5. 1 General
The induced-draft fan should be constructed of mild steel and be capable of
withstanding 600°F. The fan should be capable of at least two-speed operation or
have a variable speed drive that is adjustable from maximum delivery volume to
one-third of maximum delivery volume. Controls of this type permit the operator
to reduce the volume handled by the fan when the incinerator is operating at less
than the rated capacity. The resultant reduction in cooling in turn will increase the
operating temperature within the incinerator and reduce the possibility of water
carry-over from the scrubber. The controls for such a fan should be readily
accessible to the operator so that he can reduce the fan speed and thus increase the
overall efficiency of the incinerator. The fan housing should have a cleanout door
and a water drain.
8.5.2 Design Parameters
8. 5. 2. 1 Volume Requirements The fan should be sized to deliver 700 cubic
feet per minute of gas at 350°F for every 100 pounds per hour refuse capacity of
the incinerator.
8.5.2.2 Static Pressure Requirements The fan should provide 1/2-inch of
water static pressure, at 350°F, for a 50-pound-per-hour incinerator. Its ability
to develop static pressure should increase uniformly so that it will develop 1-1/2
inches of water, at 350°F, for a 2000-pound-per-hour incinerator. Fans opera-
ting at 350°F develop approximately two-thirds of the static pressure for which
they are rated at ambient temperatures. Consequently, the induced-draft fan
selected should be able to develop static pressures 50 percent higher than those
desired at 350°F. For example, a. fan selected for a 50-pound-per-hour incinera-
tor should develop a static pressure of 3/4 inch of water at ambient temperatures,
and a fan for a 2000-pound-per-hour incinerator should develop a static pressure
of 2-1/4 inches water at ambient temperatures.
8.5.2.3 Horsepower Requirements The horsepower requirements of the fan
should be based upon the full capacity of the fan at ambient temperature, not at
350°F.
8.5.2.4 By-Pass Arrangements For inside installations, a by-pass arrange-
ment of breechings, or flue connections with dampers, to by-pass the scrubber
and induced-draft fan is recommended.
Design Recommendations for Incinerator Scrubbers 8-7
-------
8.6 MIST ELIMINATORS
Installation of mist eliminators is not usually necessary. There are, how-
ever, occasions when water droplets may be discharged from the exhaust fan.
Should this be a serious problem, the inclusion of an eliminator section near the
top of the uppass is desirable. In general, eliminators need be installed only
when the performance of a unit has proved to be unsatisfactory.
8.7 ALTERNATE SCRUBBER DESIGNS
The following criteria should be used in the design of alternate scrubbers
or gas washers.
1. The scrubber or gas washer should contain sprays, wetted baffles, or
orifices arranged singly or in combination so as not to permit the dis-
charge of particulate matter in violation of the Code of Federal Regulations.
2. Unlined gas washers or scrubbers should have welded'or gasketed seams
and be corrosion resistant. Lined gas washers or scrubber casings
should be made of at least 12-gauge steel and be welded or gasketed.
The density of refractory lining should be no less than 120 pounds per
cubic foot. The refractory should never be less than 2 inches thick
and must be adequately anchored to the casing.
3. Scrubbers requiring an induced-draft fan should have a motor capable of
cold startup (70°F). When the impeller of an induced-draft fan is in the
gas stream, the fan must be equipped with a cleanout door and drain.
4. Where .spray nozzles are employed, an optimum spray pattern must be
provided to cover all the area of the gases as they pass through the gas
washer or scrubber. Nozzles and valves should be arranged for indepen-
dent removal by means of unions or flanges. When water is re circulated,.
a pressure regulator and a strainer should be provided.
5. An access door for cleanout should be provided on all scrubbers.
6. Interlocks should be provided when induced-draft fans and sprays are
used.
7. When the outside skin temperature of a gas •washer or scrubber exceeds
260eF, protection should be provided.
8-8 INCINERATION GUIDE
-------
8. For inside installations, a by-pass arrangement of breeching, or flue
connections with dampers, to by-pass the scrubber and induced-draft fan
is recommended.
Design Recommendations for Incinerator Scrubbers 8-9
-------
9 RECOMMENDATIONS FOR CONSTRUCTION
This Guide sets forth minimum construction standards. When a designer
feels additional strength or resistive qualities are required because of special
applications, he should include them in his specifications. It is not, however,
the intent of this Guide to preclude the use of specialty refractory materials for
construction even though such special refractory does not have all the resistive
qualities of the refractories outlined herein. Such refractory material may be
used in certain areas where its special characteristics are of particular advan-
tage, provided the materials have all the resistive qualities required for the area.
For example, where weight of the structure is an important factor, insulating
firebrick or insulating castable refractory may be used, but they cannot be used
in any area where they will be subject to abrasion from tools, materials, or
high-velocity gases.
9.1 MATERIALS OF CONSTRUCTION
Throughout this section reference is made to refractories in an abbreviated
manner such as high heat duty and super duty. For exactitude, the American
Society for Testing and Materials (ASTM) specifications for these materials follows.
9.1.1 High-Temperature Block Insulation
The high-temperature block insulation required by this Guide is in accord-
ance with ASTM Designation C-392-63 Class 2 and has the following physical
properties.
Density 14 to 20 lb/ft3
Service temperature up to 1800°F
Moisture absorption nil
Fire resistance incombustible
Linear shrinkage at 1800°F. (max.) 4.0 percent
Thermal conductivity in Btu per inch per square foot (maximum) per hour is as
follows:
200°F mean temperature 0.36
600°F mean temperature 0.51
1000°F mean temperature 0. 755
9-1
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9.1.2 High-Heat-Duty Firebrick
The high-heat-duty firebrick required by this Guide is classified as spall
resistant in accordance with ASTM Designation C-106-67. It has the following
physical properties:
Pyrometric cone equivalent 31-1/2 minimum
Panel spalling loss (2910°F) 10 percent
Modulus of rupture 500 psi minimum
9.1.3 Super-Duty Firebrick
The super-duty firebrick required by this Guide is classified as spall resis-
tant in accordance with ASTM Designation C-106-67. It has the following physical
properties:
Pyrometic cone equivalent 33 minimum
Panel spalling loss (3000°F) 4 percent maximum
Reheat shrinkage (2910°F) 1 percent maximum
Modulus of rupture 600 psi minimum
9.1.4 Class C Hydraulic Castable Refractory
The hydraulic setting castable refractory required to meet the minimum
standards of this Guide is in accordance with ASTM Designation C-213-66 Class C
and has the following physical properties:
Service temperature 2600°F maximum
Permanent linear shrinkage 1. 5 percent after heating to
2500 °F for 5 hours
Modulus of rupture 300 psi after drying to 220°F
9.1.5 Class D Hydraulic Castable Refractory
The hydraulic setting castable refractory required to perform satisfactorily
in areas of high-heat flux, such as in the arches of pathological incinerators,
should meet the provisions of ASTM Designation C-213-66 Class D and have the
following physical properties:
Service temperature 2800°F maximum
Permanent linear shrinkage 1. 5 percent after heating to ,
2700 °F for 5 hours
Modulus of rupture 300 psi after drying to 220"F
9-2 INCINERATION GUIDE
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9.1.6 Use of Castable Refractories
All castable refractory walls should be installed to form a monolithic struc-
ture and should be anchored to the exterior shell of the incinerator. Suspended
arches should be constructed so that their weight does not rest on the refractory
walls. Alloy steel or refractory anchors should be used and spaced not more than
24 inches horizontally and vertically, and in accordance with the refractory manu-
facturer's recommendations.
All such castable material should be delivered to the job site in containers
with the manufacturer's name and instructions stamped thereon. The manufac-
turer's written instructions should be followed for the preparation and application,
and also for its curing.
9-1.7 Insulation Castable Refractories
Although other types of insulating castable refractories may be used as their
resistive properties warrant, two classes, one for areas receiving direct-flame
radiation, and the other for areas that do not normally receive direct-flame radia-
tion, are recommended herein.
9.1. 7. 1 Class Q Insulating Castable Where weight is a problem, as in an after-
burner, and there is no abrasion from tools, materials, or gases, and the refrac-
tory is to receive direct-flame radiation, the minimum refractory employed must
not be less resistive than that given in ASTM Designation C-401-60 for Class Q
Insulating Castables. Certain physical properties of this class follow:
Permanent linear shrinkage 1. 5 percent maximum when fired
at 2300°F for 5 hours
Maximum bulk density 95 Ib/ft after drying to
220°F
9.1.7.2 Class O Insulating Castables Where there is no abrasion from tools,
materials, or gases and the refractory will not normally receive direct-flame
radiation, as in a s-tack, the minimum refractory employed must not be less re-
sistive than that given in ASTM Designation C-401-60 for Class O Insulating Cast-
ables. Certain physical properties of this class follow:
Permanent linear shrinkage 1. 5 percent maximum when fired
at 1900°F for 5 hours
Maximum bulk density 65 Ib/ft3 after drying to 220 °F
Recommendations for Construction 9-3
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9.1.8 Air-Setting Plastic Refractory
Two types of air-setting plastic refractory are specified byASTM Designation
C-176-67: high duty and super duty. The high-duty material represents the
minimum type of air-setting plastic refractory recommended by this Guide. The
super-duty material is recommended for use in areas of high-heat flux, such as
the arches of pathological incinerators.
9- 1. 8. 1 High-Duty Plastic Refractory The high-duty air-setting plastic re-
fractory required by this Guide is in accordance with ASTM Designation C-176-67.
It has the following physical properties:
Water content 15 percent maximum as received
Workability index 15 35 percent deformation
Pyrometric cone equivalent 31 minimum
Maximum reheat shrinkage 3 percent
Panel spalling loss 15 percent (2910°F)
9. 1.8.2 Super-Duty Plastic Refractory The super-duty air-setting plastic
refractory recommended by this Guide is in accordance with ASTM Designation
C-176-67. It has the following properties:
Water content 15 percent maximum as received
Workability index 15 35 percent deformation
Pyrometric cone equivalent 32-1/2 minimum
Maximum reheat shrinkage 2. 5 percent
Panel spalling loss 5 percent (3000°F)
9-1.9 Use of Air-Setting Plastic Refractories
All plastic refractory walls should be installed to form a monolithic structure
and should be anchored to the exterior shell of the incinerator. Suspended arches
should be constructed so that their weight does not rest on the refractory walls.
Alloy steel or refractory anchors should be used and spaced not more than 24 inches
horizontally and vertically, and should be of flexible design, and installed according
to the refractory manufacturer's instructions.
The plastic refractory should be delivered to the job site in containers with
the manufacturer's name and instructions stamped thereon. The manufacturer's
written instructions should be followed in preparing and applying the plastic and
also in its curing and baking.
9-4 INCINERATION GUIDE
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9.1.10 Air-Setting Refractory Mortar
The air-setting refractory mortar required by this Guide should meet the
requirements for the high duty classification under ASTM Designation C-178-47
(1958). The mortar should have the following physical properties:
Refractoriness test temperature 2730°F
Maximum water content 25 percent
Bonding strength of joints 200 psi
Particle size 95 percent No. 20 ASTM sieve
If super-duty refractories are used, it is recommended that mortars meet
the super-duty class of ASTM Designation C-178-47 (1958).
9.1.11 ASTM Standards
Should questions arise about specifications for any refractory or insulation
construction, they may be resolved by reference to the appropriate ASTM Designa-
tion referred to above. Where ASTM Designations are modified, the latest modifi-
cation should be followed.
9.2 GENERAL REFUSE INCINERATORS
There are as many methods of erecting the walls of a multiple-chamber
incinerator as there are materials from which to build them. The exterior of the
incinerator may be either brick or steel plate construction. Refractory lining
may be firebrick, castable refractory, or plastic firebrick. Protection of exterior
walls from extreme temperature conditions may be provided by either peripheral
air space, air cooling passages, or insulation. Stacks, in small to medium size
incinerators (less than 750 pounds per hour refuse) may be mounted directly on
the incinerator, may be free standing, or may be an integral part of the building
structure of the incinerator.
Incinerators with capacities of 500 pounds per hour or less, will usually be
prefabricated. Larger size units, and some specially designed smaller units, are
erected on the site.
The most important element of multiple-chamber incinerator construction,
other than the basic design, is the proper installation and use of refractories. The
manufacturer must use suitable construction materials and be experienced in high-
temperature furnace fabrication and refractory installation. Service conditions
Recommendations for Construction
9-5
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should dictate the type of lining for any furnace when a choice of available materials
is made.
9.2.1 Refractories for Walls and Arches
The minimum refractory specification recommended for firebrick used in
walls and arches of incinerators is the classification of high-heat duty. Firebrick
should be laid in air-setting high temperature cement. Equivalent duty hydraulic -
setting castable refractory and air-setting plastic refractory should be suitably
anchored to the exterior wall.
Recommended minimum exterior wall thickness of incinerators is as follows:
1. Up to and including 500 Ib/hr refuse capacity all refractories, whether
firebrick, castable, or plastic, should be a minimum of 4-1/4 inches thick.
2. Over 500 Ib/hr of refuse capacity, all refractories should be a minimum
of 9 inches thick.
The minimum thickness of interior refractory walls (i.e. , those walls in-
side the incinerator, the bridge wall, curtain wall, or parting wall) will generally
follow the recommendations for the exterior walls. The bridge wall, with its
internal secondary air distribution channels, will require greater thickness. The
minimum width of refractory material between the air channel and the ignition or
charging chamber, should never be less than 2-1/2 inches in the very small size
units, 4-1/2 inches in units up to 250 pounds per hour, and 9 inches in units
larger than 250 pounds per hour.
Sufficient expansion joints in the refractory construction are necessary to
prevent bulging and destruction of the walls and arches. Each foot of wall made
with firebrick clay refractory will expand when heated and contract when cooled
from 1/16 to 3/32 inch. Provisions for vertical expansion should be sufficient
between the arch and sidewalls to allow for the vertical movement. Horizontal
expansion of the various vertical walls will have to be provided for. No hard and
fast rules may be laid down for the provision of expansion joints. Their proper
design requires complex calculation based on the experience of the contractor and
engineering knowledge.
9.2.2 Insulation Requirements
Where the incinerator is constructed with a steel plate exterior wall, insula-
tion must be used between the refractory wall and the steel plate. A high-
9-6 INCINERATION GUIDE
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temperature insulating block should be used. Minimum thickness for insulation is
2 inches. Units larger than 500 pounds per hour should have 2-1/2 inches. Loose-
fill insulation is not satisfactory because of its packing into the lower portion of
the unit over long periods of time. When the exterior wall is of regular clay brick
construction, a minimum of 1 inch air space between the exterior brick and the
refractory brick, with adequate venting of the insulating air space should be pro-
vided.
9.2.3 Exterior Casing
Minimum thickness of steel plates used for the exterior casing of multiple-
chamber incinerators should be 12 gauge. The steel casing and the structural
framework should be erected and set plumb before any brickwork is started. The
exterior, or steel casing, should be reinforced with structural members, or if the
exterior is brick, should be reinforced with structural steel to withstand interior
thrusts from all arches and to support all doors, burners, and appurtenant assem-
blies. Exterior brick walls and casings must conform to minimum building code
structural requirements, but in no instance, where clay or shale brick is used,
should the exterior walls be less than 8 inches thick.
9.2.4 Floors
The thickness of refractory lining and insulation for the floors of multiple-
chamber incinerators is dependent primarily on their physical location. For in-
cinerators installed on their own concrete foundations outside of buildings, 2-1/2
inches of firebrick lining backed by 1-1/2 inches of high-temperature insulating
material will be satisfactory. Heat transfer through this insulation will be high;
but if the concrete pad cracks, only minor damage •will occur. Portable incinera-
tors mounted on 4-inch channels will have sufficient air space provided beneath
the incinerator to eliminate possible damage to the pad. When incinerators are
installed within buildings, provisions should be made to prevent physical damage
to the building. Building damage can be eliminated by providing cooling passages
beneath the incinerator, thus preventing excessive heat from reaching the struc-
ture. Additional insulation should be provided within the floor of the incinerator
when cooling passages are not feasible. For incinerators up to 500 pounds per
hour, 4-1/2 inches of firebrick and 2-1/2 inches of insulation should be provided
on the floor of the mixing and final combustion chambers. For incinerators with
capacities of 500 to 2000 pounds per hour, 4-1/2 inches of firebrick backed by 4
inches of insulation should be provided.
Recommendations foi Construction 9-7
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9.2.5 Foundations
Foundation requirements for all incinerators are determined by the weight
of the incinerator and the soil conditions. The prefabricated, portable units have
sufficient air space between them and the foundation to prevent any problem. The
on-site constructed units must provide either air insulation or a layer of insulating
material.
Prefabricated incinerators should have a minimum of three heavy supports
beneath their floors to provide support for their three bearing walls and to permit
them to be moved safely.
When incinerators are mounted on floors, the floors should be of fire-resis-
tant construction with no combustible material against the underside of the floor,
or on fire-resistant slabs or arches having no combustible material against the
underside thereof. Such construction should extend not less than 3 feet beyond
the appliance on all sides, and it should extend not less than 8 feet at the front
or side where ashes are removed.
9.2.6 Charging Doors
Guillotine charging doors used in the recommended design should be lined
with refractory material with a minimum service temperature of 2600°F. Units
of less than 100 pounds per hour capacity should have door linings at least 2-inches
thick. In the size range of 100 to 350 pounds per hour, lining thickness should be
increased to 3 inches. From 350 pounds per hour to 1000 pounds per hour, the
doors should be lined with 4 inches of refractory. On units of 1000 pounds per
hour and larger, linings should be 6 inches thick.
9.2.7 Grates
Grates should be made of cast iron and weigh at least 40 pounds per square
foot. They should have at least 40 percent open area. Because the length of the
ignition chamber increases as the size of the incinerator increases, especially in
incinerators larger than 750 pounds per hour, the rear section of the grate is
difficult to keep completely covered. The use of a solid hearth at the rear of the
ignition chamber in these units is therefore good practice. Hearths at this'location
i .'
prevent open areas from being formed in the refuse pile that is normally thin at
the rear of a long ignition chamber. The solid hearth prevents excessive underfire
air from entering immediately in front of the bridge wall. Such underfire air
9-8 INCINERATION GUIDE
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will quench the hot gases and cause excessive carryover of ash and unburned
material into the mixing chamber. Sloping grates (grates that slant down from the
front to the rear of the ignition chamber) facilitate proper charging. The sloping
grate results in an increased distance between the arch and the grate at the rear
of the chamber, reducing the amount of fly ash entrainment.
9.2.8 Air Inlets
All combustion air inlets should provide positive control. While round
"spinner" controls with rotating shutters should be used for both underfire and
overfire air openings in retort incinerators, they should only be used for under-
fire air openings in the in-line incinerator. Rectangular ports with butterfly or
hinged dampers should be provided for all secondary air openings and overfire
air openings of in-line incinerators. All air inlet structures should be of cast
iron. Sliding rectangular dampers become inoperative and should not be used.
9.2.9 Flues
When flue gas temperature is not reduced, flue connections or breechings
must be constructed with a Number 12 U.S. gauge steel exterior, lined with refrac-
tory, and provided with a guillotine or horizontal sliding damper. Flue connections
and breechings having an internal cross-section of not more than 350 square inches
should have high heat duty refractory lining 2-1/2 inches thick, and high heat duty
refractory 4-1/2 inches thick for those having an internal cross-section of more
than 350 square inches. Guillotine dampers provided for draft regulation should
be properly counterbalanced, and horizontal dampers should be equipped with suit-
able rollers and tracks to insure easy operation. The dampers should be con-
structed of a steel frame with refractory lining or they may be constructed entirely
of alloy steel to withstand the high temperature. All such dampers should be pro-
vided with a damper box constructed of Number 12 U.S. gauge steel to completely
house the damper when in its open position. When a barometric damper is also
provided, its free area should not be less than the percentage of the cross-sectional
area of the flue connection, breeching, or stack in which it is located, as called
for in Section 12. Gas velocity in any flue connection or breeching should not
exceed 30 feet per second, calculated at 1400°F.
9.2.10 Chimneys (Stacks)
The construction of incinerator chimneys (stacks) may vary from location
to location, and local building and fire protection codes must be consulted. All
Recommendations for Construction 9-9
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chimneys exposed or partially exposed to wind load should be designed to withstand
the dynamic load imposed by 100-mile-per-hour wind in addition to the dead load.
Incinerator chimneys should extend not less than 4 feet above a sloping roof
measured from the highest point of penetration of the chimney through the roof
and at least 8 feet above a flat roof. In no case shall the chimney (stack) be less
than 2 feet above any obstruction or portion of the building within a 20-foot radius.
Local codes should be consulted for regulations requiring greater heights than
those given herein.
Prefabricated refractory-lined chimneys, or stacks, with the refractory
providing the structural strength, may be used. The thickness of the refractory
lining and the class of refractory used should be in accordance with the Under-
writers Laboratory approved listing. The exterior jacket should be a minimum of
28 gauge galvanized steel or stainless steel. Adequate support, without placing
any of the load on the refractory walls of the incinerator, must be provided for any
stack installed on top of an incinerator.
Prefabricated steel refractory-lined chimneys, or stacks, with the steel
casing providing the structural strength, may be used. The steel casing should be
designed in accordance with acceptable structural design practice and the thickness
of the steel should not be less than shown in Table 9-1.
Table 9-1. MINIMUM THICKNESS FOR STEEL
STACK WALLS
Stack diameter, inches
Up to 28
29 to 48
49 to 80
Thickness
12 gauge
3/16 inch
1/4 inch
The refractory lining should conform to ASTM Classification C-401-60 Class
Q. The thickness of the refractory lining should not be less than shown in Table
9-2.
Table 9-2. MINIMUM REFRACTORY STACK
LINING THICKNESS
Stack diameter, inches
Up to 28
29 to 48
49 to 80
Thickness, inches
2
3
4
9-10 INCINERATION GUIDE
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The refractory lining should be secured to the steel shell by means of stain-
less steel anchors or steel shelf angles. The spacing of the anchors should not be
more than 24 inches on centers with a minimum of 4 anchors per perimeter.
Firebrick-lined steel chimneys or stacks should be constructed of not less
than 12 gauge steel and should be designed in accordance with acceptable structural
steel practices. The steel shell should have a 4-1/2-inch firebrick lining for the
full height.
Masonry chimneys or stacks may be used, but in no case should the firebrick
lining be anchored to the exterior masonry shell. A clear air space must be pro-
vided between the exterior shell and the firebrick lining.
Brick masonry chimneys or stacks should be constructed with a minimum
wall thickness of 8 inches of common brick with a 4-1/2-inch-thick firebrick
lining for the full height.
Concrete chimneys or stacks should be constructed with a minimum shell
thickness of 6 inches of concrete with a 4-1/2-inch-thick firebrick lining for the
full height.
Stone chimneys or stacks should be constructed with a minimum wall thick-
ness of 12 inches of stone masonry with a. 4-1/2-inch-thick firebrick lining for the
full height.
Radial brick chimneys or stacks should be constructed with a minimum wall
thickness of 7-1/2 inches of radial brick with a 4-1/2-inch-thick firebrick lining
for the full height.
Unlined steel chimneys or stacks may be used only when flue gas tempera-
tures do not exceed 600 °F, and the interior is protected against corrosion from the
flue gas by a suitable temperature-, moisture-, and acid-resistant coating. How-
ever, unlined steel chimneys or stacks are not permitted on incinerators with
emergency gas washer bypass flues, where the possibility of high-temperature
gases in the chimney exits. Corrosion protection of the steel chimney is required
because of the presence of moisture in the flue gases carrying an appreciable
degree of acidity. Condensation of water vapor with acid characteristics will cause
rapid deterioration of steel chimneys, especially on outside installations.
Recommendations for Construction 9-11
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9.2.11 Clearances
Incinerators should be installed to provide a clearance to combustible mate-
rial of not less than 36 inches at the sides and rear, and not less than 48 inches
above, and not less than 8 feet at the front of the incinerator; except in the case
where an incinerator is encased in brick, then the clearance may be 36 inches at
the front and 18 inches at the sides and rear. A clearance of not less than 1 inch
should be provided between incinerators and walls or ceilings of noncombustible
construction. Walls of the incinerator should never be used as part of the struc-
tural walls of the building.
9.2.12 Incinerator Rooms or Compartments
1. When the combined hearth and grate area of the combustion chamber of an
indoor incinerator is 7 square feet or less, the incinerator should be
enclosed within a room that is separated from other parts of the building
by walls, floor, and ceiling assemblies having a fire resistance rating of
not less than 1 hour, with floor of earth or other noncombustible material,
and used for no other purpose other than storage of waste materials and
refuse to be burned or building heating equipment. Openings to these
rooms should be protected by self-closing or automatic fire doors suitable
for Class B situations (metal-clad doors) as defined in National Fire Pro-
tection Association Standard 80, Fire Doors and Windows, 1967.
2. Incinerators where the combined hearth and grate area of the combustion
chamber exceeds 7 square feet, should be enclosed within a room that is
separated from other parts of the building by walls, floor, and ceiling
assemblies which are constructed of noncombustible material that has a
fire resistance rating of not less than 2 hours and have a floor of earth
or other noncombustible material, and used for no other purpose except
storage of waste material and refuse to be burned or building heating
equipment. Openings to such rooms should be protected by self-closing
or automatic fire doors suitable for Class B situations (metal-clad doors)
as defined in the National Fire Protection Association Standard No. 80,
Fire Doors and Windows, 1967.
3. Automatic sprinklers and a short length of hand hose connected to a. suit-
able water supply are recommended in the incinerator room.
9-12 INCINERATION GUIDE
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9.2.13 Rubbish or Refuse Chutes
Rubbish or refuse chutes should rest on substantial noncombustible founda-
tions. Thickness of enclosing walls of refuse chutes should be 8 inches of shale
brickwork or clay, or 6 inches of reinforced concrete. Such chutes should extend
at least 4 feet above the roof and be covered by a metal skylight, glazed with thin
plain glass.
9.2.14 Chute Terminal Rooms or Bins
1. Rubbish or refuse chutes should terminate in, or discharge directly into,
a room or bin that is separated from the incinerator room and from
other parts of the building, by walls, floor, and ceiling assemblies that
have a fire resistance rating equal to chute specifications. Openings to
such rooms or bins should be protected by self-closing or automatic fire
doors suitable for Class B situations (metal-clad doors), as defined in
the National Fire Protection Association Standard No. 80, Fire Doors and
Windows, 1967.
2. Properly installed automatic sprinklers provide a reliable and effective
means for fire extinguishment and should be installed in all chute termi-
nal rooms or bins, particularly where combustible waste is handled. A
short length of hand hose connected to a suitable water supply should
also be provided. Fires occurring at chute terminals are usually
difficult to control because of the large amount of smoke evolved, causing
access by the fire department to be difficult. Automatic extinguishment
of such fires in the early stage is therefore of primary importance.
9.2. 15 Ventilation of Incinerator Rooms
Rooms containing incinerators should be supplied with an adequate amount of
air for combustion and ventilation. Air supply may be furnished by one of the
following means:
1. A screened or louvered ventilator opening, or other suitable air intake.
If communicating to other parts of the building the opening should be pro-
tected by a fire damper.
2. A duct leading from the incinerator room to the outside.
3. A duct leading to a boiler or furnace room as prescribed in Section
9. 2. 12 for incinerators of a given capacity, with sufficient air supply
provided for both rooms.
Recommendations for Construction 9-13
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Ducts extending from an incinerator room to other parts of a building should
be constructed and protected in accordance with the National Fire Protection
Association Standard No. 90A, Installation of Air Conditioning and Ventilating
Systems of Other than Residence Type.
9.3 PATHOLOGICAL INCINERATORS
The general discussion for the construction, insulation, and refractory
specifications of multiple-chamber incinerators given in Section 9.2, will cover
most of the problems to be found in constructing pathological incinerators. The
use of super-duty refractories, particularly in the arches of these units, is desir-
able. Refractory walls, roof, hearth, parting wall, curtain wall, and baffles should
not be less than 4-1/2 inches thick for incinerators with a capacity up to 150 pounds
per hour. Incinerators with a capacity of over 150 pounds per hour should have at
least 9-inch thick refractory in walls, roof, hearth, parting wall, curtain wall, or
baffles.
Hearth construction must have the physical strength to sustain maximum
loads at elevated temperatures. Initial charges for pathological waste incinera-
tors could have a total weight in excess of the hourly capacity of the unit; therefore,
hearths should be designed for loadings of at least twice the hourly burning rate.
9-14 INCINERATION GUIDE
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10 MISCELLANEOUS RECOMMENDATIONS
10.1 STACK VIEWER
When possible, it is advisable to arrange a system of mirrors to allow an
incinerator operator, who would otherwise be unable to see the top of the stack
because of his location, to view the stack outlet.
10.2 RECOMMENDATIONS FOR SAMPLING PORTS
Each new incinerator stack should have two sampling ports 3-1/2 inches in
diameter. Each port should be positioned in the stack at right angles to each other.
They should be located, when possible, eight to ten stack diameters downstream
from any bend or disturbance of gas flow, and two stack diameters upstream of the
exit of the stack. The ports should be provided -with suitable removable, replace-
able caps.
10-1
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11 OPERATING PROCEDURES
11.1 GENERAL-REFUSE INCINERATORS WITHOUT SCRUBBERS
The emission control of the multiple-chamber incinerator is built in. Even
so, the discharge of smoke or solid contaminants is in large measure a function
of the action of the operator, and to some degree, the type of material charged.
Smoke control is attained by the proper admission of air for combustion and by
proper utilization of secondary burners, where the refuse has a low heating value
or a high moisture content. Use of the secondary burners is required occasionally
to maintain the combustion efficiency of the secondary chamber. Proper function-
ing of this chamber depends upon luminous flames and a temperature adequate for
gaseous-phase combustion. Use of secondary burners is readily determined by
observations of the flame travel from the ignition chamber, and flame coverage at
both the f lameport and the curtain wall port.
Before any incinerator is placed into operation, the grate and the ash pit
beneath should be cleaned and the damper properly adjusted. Incinerators with
full ash pits concentrate heat on the grates, causing them to soften, bend, and
even fall from their mountings.
The secondary burner, or burners, should be ignited a few minutes before
the incinerator is charged in order to heat the secondary chambers. The charging
and clean-out doors should be closed, and the air ports open during this preheat-
ing period. Should the flames from the secondary burners be driven upward and
through the flameport when ignited, instead of downward through the mixing cham-
ber in incinerators with natural draft, the burners should be shut off. To over-
•come this problem, a small piece of paper may be inserted through the clean-out
door in the combustion chamber, and ignited. The door is then closed and the
secondary burners are re-ignited. The burning paper in the combustion chamber
will direct the movement of air up the stack and result in proper operation of the
burners.
The overfire and underfire air ports should usually be approximately half-
open at lightoff. They should be opened gradually to an open position, as the in-
cinerator reaches stable operation at its rated burning capacity. Air admission
11-1
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is usually not critical during normal incineration.
The most important single aspect of the operation of multiple-chamber in-
cinerators is the charging of the refuse into the ignition chamber. Proper charg-
ing is necessary to reduce the issuance of fly ash, to maintain adequate flame
coverage of the burning rubbish pile and the flameport, and to prevent the fuel bed
from becoming too thin at the rear of the ignition chamber in the larger units.
The initial charge should fill the ignition chamber with refuse to a depth of
one-half to three-quarters the distance between the pile below the flameport
opening. The initial charge should be ignited at the top rear of the pile below the
flameport opening, and the charging door closed. The primary burners in the
ignition chamber are used when the refuse is very moist. If use of this burner is
required, care should be exercised to prevent the blocking of the primary burner
by the refuse pile.
When approximately one-half of the initial refuse charge has been burned,
the remaining refuse may be carefully stoked. The burning refuse should then be
pushed as far as possible to the rear of the grates. This operation should be per-
formed carefully to prevent excessive emission of fly ash. Additional refuse may
now be charged to the incinerator. The new refuse should be charged at the front
section of the grates but not on top of the burning pile already in the incinerator.
This method of charging will prevent smothering the fire and will maintain live
flames over the entire rear half of the chamber, filling the flameport and extend-
ing well into the mixing chamber. Flames will propagate evenly over the surface
of the newly charged material, minimizing the possibility of smoke emissions.
This method of charging also minimizes the necessity of stoking or otherwise
disturbing the burning pile, so that little, if any, fly ash is emitted. After the
waste material has been charged into the incinerator, the unit enters the "burn-
down" phase of its operation. When the last charge has been reduced to one-half,
or less, of its original size, all air port openings to the incinerator are reduced
to one-half open. The secondary burners are always left on, until the issuance of
smoke from any material remaining on the grates has ceased. At this time, all
burners are shut off.
When incinerators are burning only paper, caution is always exercised to
insure that the burning pile at the rear of the grate does not become too thin.
Should this happen, excessive underfire air admitted at this point quenches the
11-2 INCINERATION GUIDE
-------
hot gases entering the flameport, reduces combustion and produces smoke with
as high as 100 percent opacity. Use of adequate secondary burners will prevent
the incomplete combustion resulting from the thin bed at the rear of the ignition
chamber.
Smoke emissions around the charging door or ash pit door, or both, usually
result from overcharging. The following steps, in sequence, have been found to
successfully eliminate smoke:
1. Check damper adjustment.
2. Shut off the primary burner, if operating.
3. Observe the burning pile, and move any material blocking the flame port.
4. Make sure that the clean-out doors, or doors in any of the secondary
chambers of the incinerator, are closed. Any air port on these doors
should also be closed.
5. Allow the fuel bed to burn down to normal operating depth, and do not
overcharge the incinerator again.
White smoke appearing at the incinerator stack is usually caused by excess
air entering the incinerator. The following steps, in sequence, have been
found to eliminate white smoke:
1. Check damper adjustment.
2. Ignite the secondary chamber burner, or check to see that it is still
burning.
3. Close the secondary air port, or ports.
4. Close the underfire air port.
5. Reduce the overfire air port opening.
6. If all the secondary burner capacity is not being used, gradually increase
the operating rate of the burner until full capacity is reached.
7. If all of these operations fail to stop the issuance of white smoke, exam-
ine the material to be charged. Possibly the white smoke is the result of
finely divided mineral material present in the charge and being carried
out the stack. Paper sacks that contain pigments or other metallic oxides,
and minerals such as calcium chloride, cause white smoke.
Operating Procedures
11-3
-------
Black smoke is usually caused by insufficient amounts of air for combustion,
or a burning rate greatly in excess of the capacity of the incinerator. The follow-
ing steps, in sequence, have been found to eliminate this black smoke:
1. Check damper adjustment.
2. Shut off the primary burner, or burners, if in operation.
3. Open the secondary air port, or ports.
4. Open the overfire air port.
5. Either ignite the secondary chamber burner, or check to see that it is
still burning.
6. If the black smoke still continues, gradually open the charging door until
it is approximately one-quarter open.
7. Should these steps fail to eliminate the black smoke, examine the mate-
rial remaining to be charged. Highly combustible materials (i.e. , rub-
ber, plastics, etc.) that are charged in too great a proportion to the
other refuse, •will result in a. too rapid combustion rate for the incinera-
tor to handle. These materials may be charged in very small quantities
and in relatively small pieces along with general refuse. If such mate-
rials must be burned frequently, experimentation as to the quantity that
may be charged along with other materials, may be necessary. Gen-
erally, highly combustible materials must be charged at less than 10
percent by weight of the total charge.
11.2 GENERAL-REFUSE INCINERATORS WITH SCRUBBERS
11.2.1 Incinerator Operation
Operation of the incinerator is the same as described under Section 11. 1.
11.2.2 Scrubber Operation
The fan should be started before either the burner or refuse is ignited. If
the interlock system described in Section 8. 3 has not been supplied, water should
be manually turned on to the scrubber. After the fan and water have been started,
burners and refuse may be ignited. If the electrical interlock system described
in Section 8. 3 is installed, the water will flow to the nozzles when the fan is started.
If, during the operation of the system, the alarm sounds to indicate too high
a fan temperature, the primary chamber burners should be shut off, charging
11 -4 INCINERATION GUIDE
-------
stopped, and the door and air ports opened to cool the incinerator. The secondary
burners may also be turned off to reduce the fan temperature to the point where
the alarm will cease operating.
Maintenance should be conducted on a regular basis. The scrubber basin
should be drained and cleaned daily. Nozzles, pumps, and the backup system
should be checked weekly.
11.3 PATHOLOGICAL INCINERATORS WITHOUT SCRUBBERS
Preheating the secondary combustion zone is essential before charging and
operating these units. The primary burner should not be ignited before charging
has been completed or the charge door closed. The waste material should be so
distributed on the hearth to assure maximum exposure to the flame of the primary
burner. Normally, deposition completely covering the hearth would provide mate-
rial in excess of the hourly capacity of the unit. To further overcharge the unit by
placing one component of the charge on top of another is improper practice. Care
should be exercised to insure that the primary burner port is not blocked by any
element of the charge. If the initial charge is too large, smoke will escape from
the incinerator doors. Experience should enable the operator to size the initial
charge, as well as subsequent charges, to avoid this condition.
Additional refuse should be charged, and the burning material stoked, after
a considerable reduction of the initial charge. The primary burner should be shut
off before the charge door is opened for stoking or additional charging.
The adjustment of air ports is usually only of minor importance in the opera-
tion of these incinerators. Adjustments to the secondary air port are usually not
necessary once it has been adjusted to provide proper operation under normal
burning conditions. The only operating difficulty will occur when large deposits of
fatty tissue or hair are exposed'to the burner flame. The sudden volatilization of
this material causes a rush of gases and vapors through the unit, and black smoke
may issue from the stack. This surge of gas, if very large, could pressurize the
ignition chamber and cause smoke to be forced out around the charging door. When
this occurs the ignition chamber burner should be throttled down. Under excep-
tional conditions it may be necessary to shut the ignition chamber burner off for a
few minutes. White smoke issuing from the stack usually indicates low incinerator
temperatures, and is best overcome by increasing secondary or primary burner
rates. Occasionally, adjustment of the secondary air port to decrease the
Operating Procedures 11-5
-------
admission of cold air is necessary.
There is essentially no "burndown" period in the operation of pathological
waste incinerators. The degree of destruction desired for the waste material will
dictate the length of time the primary burner is left in operation. Burning is
normally ended when the material has been reduced to clean, white bone. When
reduction of the bone to powdery ash is desired, the primary burners may be
continued in operation. The secondary burner should not be shut off, however,
until smoldering from the residual material on the hearth in the primary chamber
has stopped.
The hearth should be frequently cleaned to prevent buildup of ash residue.
The frequency with which the combustion or settling chamber is cleaned will de-
pend on incinerator use. Deposits in this chamber should be removed to avoid re-
entrainment in the exit gases with further use of the incinerator.
11-6 IN CINERATION GUIDE
-------
12 THEORETICAL BASIS FOR GENERAL-REFUSE INCINERATOR
DESIGN RECOMMENDATIONS
12.1 PRINCIPLES OF COMBUSTION
The principles of solid fuel combustion that generally apply to incineration
and basic precepts for combustion efficiency include the following:
1. Air and fuel must be in proper proportion.
2. Air and fuel, especially combustible gases, must be mixed adequately.
3. Temperatures must be sufficient for ignition of both the solid fuel and
the gaseous components.
4. Furnace volumes must be large enough to provide the retention time
needed for complete combustion.
5. Furnace proportions must assure that the ignition temperatures are
maintained and fly ash entrainment is minimized.
The problem of fuel quality fluctuation is one of the factors that makes satis-
factory incinerator design difficult. In addition to the wide ranges of fuel composi-
tion, moisture and volatility, there is diversity in ash content, bulk density, heats
of combustion, burning rates, and component particle sizes. All of these affect,
to some extent, the operating variables of flame propagation rate, flame length,
combustion air requirements, and the need for auxiliary heat.
The ignition process consists primarily of fuel-bed surface combustion,
attained by maximum utilization of overfire combustion air, limited use of under-
fire air, and a method of charging to attain concurrent travel through the ignition
chamber of the air and refuse.
12.2 IGNITION CHAMBER PARAMETERS
The desired ignition mechanism of fuel bed surface combustion is attained by
using a predominance of overfire combustion air and a method of charging that
provides concurrent travel of air and refuse. Underfire air must be severely
restricted to maintain a relatively low fuel-bed temperature and to limit the en-
trainment of solid particulate matter in the combustion gas stream from the
12-1
-------
chamber. Locating the charging door at the end of the ignition chamber farthest
from the flame port permits the refuse to move through the ignition chamber from
the front to the rear. This design and method of charging ensures that volatiles
from the fresh charge will pass through the flames of the stabilized and heated
portion of the burning fuel bed. Thus, the rate of ignition of unburned refuse is
controlled, and the flash volatilization, flame quenching, and smoke creation
normally encountered -with top and side charging methods are avoided. Top or
side charging is not considered acceptable because of the suspension of dust, dis-
turbance of the fuel bed, and additional stoking required.
The ignition chamber of retort incinerators with rated capacities up to 500
pounds per hour should have a length-to-width ratio of from 2:1 to 2. 5:1. Retorts
over 500 pounds per hour capacity should have a length-to-width ratio of 1.75:1.
For in-line incinerators, the length-to-width ratio starts at 1,75:1 for the 750-
pound-per-hour capacity unit and diminishes linearly to approximately 1.2:1 for
incinerators in the 2000-pound-per-hour capacity range.
The arch height and permissible grate loadings for incinerators are deter-
mined on the basis of their hourly burning capacity from Figures 12-1 and 12-2.
2,000
1,000
500
400
300
z
o
co
LG = 10 LOG Rc
FOR DRY REFUSE AND HIGH
HEATING VALUES, USE +10% CURVE
FOR MOIST REFUSE AND LOW
HEATING VALUES, USE -10% CURVE
20
10
20 30
GRATE LOADING (LG), Ib/ff2-hr
Figure 12-1. Relationship of combustion rate to grate loading for multiple-chamber incinerators.
12-2
INCINERATION GUIDE
-------
o
IU
r
i
u
9
8
7
6
5
4
3
2
.4
<&
&
,
**^r +
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*
,
.»* .
.**'
,X
~?
/
X
.'
,
x
F
h
1
f
/
#*
:C
HE
I
rc
HE
^
Xx^c
u**
H/
)R DRY REF
EATING VAL
i
)R MOIST R
EATING VA
.•*
fe
>
,.«'
X
x4
-------
Table 12-1. GENERAL-REFUSE MULTIPLE-CHAMBER INCINERATOR DESIGN FACTORS
Item and symbol
Recommended value
Allowable
deviation
Q
z
o
Primary combustion zone
Grate loading
Grate area
Average arch height (HA)
Length-to-width ratio (approximate):
Retort
In-line
Secondary combustion zone 7
Gas velocities
Flame port @ 1000'F (VFP)
Mixing chamber @ 1000°F (Vyc)
Curtain wall port @ 950°F (Vg^p)
Combustion chamber (3 900°F (VCG)
Mixing chamber down-pass length (Lye) from top of ignition chamber
arch to top of curtain wall port.
Length-to-width ratios of flow cross sections
Retort, mixing chamber, and combustion chamber
In-line
Combustion air
Air requirement batch charging operation
Combustion air distribution
Overfire air ports
Underfire air ports
Mixing chamber air ports
Port sizing, nominal inlet velocity pressure
Air inlet ports oversize factors
Primary air inlet
Underfire air inlet
Secondary air inlet
Furnace temperature
Average design temperature for combustion products
Auxiliary burners
Normal duty requirements:
Primary burner
Secondary burner
Draft requirements
Theoretical stack draft
Available primary air induction draft (DA) (Assume equivalent
to inlet velocity pressure)
Natural draft stack velocity (Vg)
10 Log R0, Ib/hr-ft^; where Rc equals the refuse combustion rate in lb/hr
see (Figure 12-1)
Rc H. LG,.ft2
4/3 (AG) 4/11; ft (see Figure 12-2)
Up to 500 lb/hr 2'2:l to 2:1. Over 500 lb/hr 1.75:1
Diminishing from about 1.7:1 for 750 lb/hr to about
1.2:1 for 2,000 lb/hr capacity. Over square acceptable
in units of more than n-ft ignition chamber length.
55 ft/sec
25 ft/sec
About 0.7 of mixing chamber velocity
5 to 6 ft/sec; always less than 10 ft/sec
Average arch height, ft
1.3:1 to 1.5:1
Fixed by gas velocities because of constant incinerator width
Basis: 300% excess air. 50% air requirement admitted through adjustable
ports: 50% air requirement met by open charge door and leakage
70% of total air required
10% of total air required
20% of total air required
0.1-in. water gage
1.2
1.5 for over 500 lb/hr to 2.5 for 50 lb/hr
2.0 for over 500 lb/hr to 5.0 for 50 Ib/hr
1000°F
3,000-10,000 Btu/lb moisture in refuse
4,000-12,000 Btu/lb moisture in refuse
0.15 for 50 lb/hr
0.30 for 1,000 lb/hr Uniformally increasing between sizes
0.35 for 2,000 lb/hr
0.1-in. water gage
Less than 30 ft/sec @ 900°F
± 10%
±10%
±20%
±20%
±20%
±20°F
-------
be based upon the refuse containing the highest amount of moisture to be burned i
the incinerator.
in
Although heat release rates are not used in sizing any of the chambers in a
multiple-chamber incinerator, their values are within the acceptable limits of
furnace design. For comparative purposes, Figure 12-3 has been included for
those who are more familiar with sizing combustion equipment by this method. In
small multiple-chamber incinerators, the heat release rate approximates
30, 000 Btu per cubic foot per hour, and in the largest of the in-line units the heat
release rate is approximately 15, 000 Btu per cubic foot per hour.
100,000
tti
LU
I-
o:
111
UJ
o:
LU
I
10,000
10 100 1.000 2.000
SIZE OF INCINERATOR, Ib/hr
Figure 12-3. Heat release rates for general-refuse incinerators.
12.3 MIXING AND EXPANSION CHAMBERS
The mixing chamber is designed to promote mixing between the effluent
from the ignition chamber, secondary air, and supplemental heat of the secondary
burner. This mixing is accomplished by sizing the flame port for a gas velocity
of from 45 to 65 feet per second at operating temperatures. The desired expan-
sion is accomplished by reducing the gas velocity in the mixing chamber to the
range of 20 to 35 feet per second. The cross-sectional area of the curtain wall
port is approximately 50 percent larger than that of the mixing chamber in order
to minimize draft losses. Restriction at the curtain wall port is not necessary
since adequate mixing has already occurred in the mixing chamber and the major-
ity of the gas phase combustion has been completed. An undersized curtain wall
port will increase the draft loss and cause the effluent from the mixing chamber to
Theoretical Basis for General - Refuse Incinerator Design Recommendations
12-5
-------
sweep the floor of the expansion chamber, thus reducing its ability to effectively
collect fly ash. On the other hand, an oversized curtain wall port will reduce the
effective length of the mixing chamber and the gaseous phase combustion in the
mixing chamber may not be completed.
During normal operation, sufficient primary combustion air is usually
available to complete the gaseous phase burning in the mixing chamber, without
use of secondary air. Occasionally the rapid volatilization of the refuse results
in a deficiency of combustion air in the ignition chamber, then smoke and other
incomplete products of combustion pass through the flame port into the mixing
chamber. Under these circumstances, secondary air is essential for complete
combustion and smokeless operation of the incinerator. Therefore, provisions
for secondary air are always made in the design of incinerators.
Whether the secondary burner is used or not when burning Type 1 refuse is
solely dependent upon the attention of the incinerator operator. Multiple-chamber
incinerators are designed to eliminate the use of secondary burners in the burning
of Type 1 refuse; however, reasonable care should be taken by the operator.
Secondary burners are required to prevent excessive smoke. The higher
moisture content of Type 2 refuse causes a difficulty in burning because of its
low gross heating value. This necessitates the continuous use of secondary
burners.
12.4 COMPARISON OF RETORT AND IN-LINE INCINERATOR DESIGN FEATURES
12.4.1 Retort Type
The retort type of design is distinguished by the following features:
1. The arrangement of the chambers causes the combustion gases to flow
through 90-degree turns in both horizontal and vertical directions.
2. The return flow of the gases permits the use of a common wall between
the primary and both secondary chambers.
3. Mixing chambers, flame ports, and curtain wall ports have length-to-
width ratios in the range of 1:1 to 2.4:1.
4. Bridge wall thickness under the flame port is a function of dimensional
requirements in the mixing and combustion chambers. The resulting
bridge wall construction is unwieldy in incinerators in the size range
above 500 pounds per hour.
12-6 INCINERATION GUIDE
-------
12.4.2 In-Line Type
Distinguishing features of the in-line design are:
1. Flow of the combustion gases is straight through the incinerator with
90-degree turns in only the vertical direction.
2. The in-line arrangement of the component chambers gives a rectangular
plan to the incinerator. This style is readily adaptable to installations
that require separated spacing of the chambers for operating, mainte-
nance, or other reasons.
3. All ports and chambers extend across the full width of the incinerator
and are as wide as the ignition chamber. Length-to-width ratios of the
flame port, mixing chamber, and curtain-wall-port flow cross sections,
range from 2:1 to 5:1.
12. 4. 3 Comparison of Types
A retort incinerator of optimum size range offers the advantages of com-
pactness and structural economy due to its cubic shape and reduction in exterior
wall length. The retort incinerator performs more efficiently than its in-line
counterpart in the capacity range of 50 to about 750 pounds per hour. The in-line
incinerator is well suited to high-capacity operation, but is not too satisfactory for
service in small sizes. The secondary stage combustion of the smaller in-line
incinerators is less efficient than retort types. The in-line incinerator functions
best when the unit has a capacity of over 1000 pounds per hour.
The in-line and retort incinerators, in the capacity range between 750 and
1000 pounds per hour, are equally efficient. The choice of the in-line, or retort
incinerator is dictated by personal preference, space limitations, and the nature
of the refuse and charging conditions.
The factors which tend to cause a difference in the performance of the two
incinerator types are: (1) proportioning of the flame port and mixing chamber in
order to maintain adequate gas velocities within the dimensional limitations im-
posed by the particular type involved, (2) maintenance of proper flame distribution
over the flame port and across the mixing chamber, and (3) flame travel through
the mixing chamber into the combustion chamber.
The additional turbulence and mixing, promoted by the turns in the retort
incinerators, allow the nearly square cross sections of the ports and chambers
Theoretical Basis for General - Refuse Incinerator Design Recommendations 12-7
-------
in small units to function adequately. In the retort sizes above 1000 pounds
per hour, the reduced effective turbulence in the mixing chamber that is caused
by the increased size of the flow cross section, results in inadequate flame pene-
tration, effluent distribution, and secondary air mixing.
As the capacity increases, the in-line model exhibits structural and perfor-
mance advantages. Certain weaknesses of the small in-line type are eliminated
as the size of the unit increases. For instance, with an in-line incinerator of less
than 750 pounds per hour capacity, the shortness of grate length in the ignition
chamber tends to inhibit flame propagation across the width of the ignition chamber.
This, coupled with thin flame distribution over the bridge wall, may result in
smoke from a smoldering fuel bed passing straight through the incinerator and
out of the stack without adequate mixing and secondary combustion. In-line models
in sizes of 750 pounds per hour or larger have grates long enough to maintain
burning across their width to provide flame distribution in the flame port and
mixing chamber. Since smaller in-line incinerators have relatively short grates,
a problem of construction is added. Usually, the bridge wall is not provided with
any structural support or backing; and because secondary air passages are built
into it, the wall is very susceptible to mechanical failure. Careless stoking and
grate cleaning in short-chambered in-line incinerators can ruin the bridge wall in
a short time.
Incinerators under 2000 pounds per hour maybe standardized for construc-
tion purposes to a great degree. However, incinerators of larger capacity are
not readily standardized because problems of construction, material usage,
mechanized operation with stoking grates, induced draft systems, and other
factors make each installation essentially one of custom design.
12.5 AIR SUPPLY
Combustion air enters a multiple-chamber incinerator at a number of loca-
tions. The quantity and location of combustion air is governed by the need to pro-
mote surface burning of the refuse in the ignition chamber. This is accomplished
by providing the majority of the combustion air over the surface of the refuse. A
small portion of air should be provided through the burning pile of refuse in order
to maintain a satisfactory and uniform burning rate. Occassionally, during the
combustion process, excessive quantities of refuse are consumed with insufficient
amounts of overfire and underfire air. If additional air is not provided elsewhere
12-8 INCINERATION GUIDE
-------
in the incinerator, smoke will be discharged from the stack. To prevent this,
additional air is provided in the mixing chamber near the top of the bridge wall.
Air introduced into this chamber is called "secondary air." When secondary air
is mixed with the smoky effluent and live flame of the secondary burner, smokeless
operation usually results.
Tests have shown that efficiently designed multiple-chamber incinerators
utilize from 100 to 300 percent excess combustion air. Approximately one-half
of the total combustion air admitted into the incinerator through the air ports is
provided for this purpose. The remaining air enters through expansion joints,
cracks, and leaks in the exterior walls of the incinerator, and through the open
charging door during the charging operation. Since approximately 50 percent of
the total combustion air is supplied through air ports, the ports are sized to
furnish a theoretical quantity of air, plus 100 percent excess air.
The overfire air port should be located at the end of the ignition chamber,
farthest from the flame port. It should be sized to admit 70 percent of the com-
bustion air. The underfire air port should be located beneath the grates and, if
possible, at the same end of the incinerator as the overfire air port and charging
door. The air port should permit admission of 10 percent of the combustion air.
The secondary air port is normally located where the bridge wall connects
with the exterior wall. It is sized to permit the admission of 20 percent of the
combustion air. An air passage is normally constructed through the exterior
wall and into the bridge wall. Small ports, located on the mixing chamber side
of the bridge wall just below the flameport, permit the entrance of secondary air.
12.6 DRAFT CONTROL
Many of today's high-rise buildings require that stacks be considerably
higher than ideal so that the effluent from the incinerator will be discharged above
the roof level. Sometimes the height of the stack must be higher than optimum so
that the incinerator effluent will exit above nearby windows. There are several
ways to reduce the draft to an acceptable level. One of the most common methods
is the use of a guillotine damper. This method has several drawbacks, the most
serious of which is the need for constant adjustment, particularly during the light-
off period, to maintain the draft at a satisfactory level. At best, this is a very
rough method for adjusting the draft and leaves much to be desired.
A more satisfactory device for controlling draft to a uniform level is a
Theoretical Basis for General-Refuse Incinerator Design Recommendations 12-9
-------
barometric damper. The barometric damper, after initial adjustment, automa-
tically regulates the draft without an operator. When the stack draft is inadequate,
the barometric damper closes. When the draft is too great, the damper gradually
opens and permits the introduction of ambient air. Air introduced through the
damper at the base of the stack cools the stack gases, and thereby reduces the
theoretical draft produced by a given stack. In addition, the introduction of air
increases the velocity through the stack, thus increasing frictional losses and,
again, reduces the available draft. If a stack higher than ideal must be installed,
Figure 12-4 may be used to size the barometric damper.
12.7 TYPICAL DESIGN CALCULATIONS
12. 7. 1 General
To use the factors itemized in Table 12-1, calculations must be made that
will yield incinerator data in usable form. The calculations fall into three general
categories: (1) combustion calculations based upon the refuse composition,
assumed air requirements, and estimated heat loss; (2) flow calculations based
upon the properties of the products of combustion and assumed gas temperatures;
and (3) dimensional calculations based upon simple mensuration and empirical
sizing equations.
u
<
H
. O
M
u u
O- LLI
I- Z)
UJ _l
CD <
0 <
< -1
O
a:
U
120
no
100
90
80
70
60
50
40
30
I I I
I I
I I I I I I I
1 I I I
20
30
40
50
60
70
80
90
100
110
120
130
HEIGHT OF CHIMNEY OR STACK ABOVE BASE OF INCINERATOR, ft
Figure 12-4. Minimum free area of barometric dampers
12-10
INCINERATION GUIDE
-------
Simplifying assumptions that are made in connection with the incineration
process should be reasonable estimates of conditions known to exist. Their value
lies in the resultant ease of application of the calculated data in preparing incinera-
tor designs and comparing them with the established parameters and with similar
satisfactory units. The simplifying assumptions upon which calculations are based
may be summarized as follows:
1. The burning rate and average refuse composition are taken as constant.
An exception may be required when extremes in material quality and
composition are encountered. The most difficult burning condition is
assumed in such cases.
2. The average temperature of the combustion products is determined
through normal heat balance calculations, except that losses due to
radiation, refractory heat storage, and residue heat content are assum-
ed to average 20 to 30 percent of the gross heating value of the refuse
during the first hour of operation. Furnace data generally available
indicate that the losses approximate 10 to 15 percent of the gross heat
after 4 to 5 hours of continuous operation.
3. The overall average gas temperature should be about 1000°F when cal-
culations are based on 300 percent excess combustion air and on the heat
loss assumptions previously given. The calculated temperature does not
indicate the probable maximum temperatures attained in the flame port
or mixing chamber. Should the temperature be lower than the calculated
value, the need for auxiliary primary burners is indicated. Burner size
should be as indicated in Table 12-1. The temperatures used in checking
gas velocities are approximations of the actual temperature gradient in
the incinerator as the combustion products cool en route from the flame
port to the stack outlet.
Air ports are sized for admission of theoretical air, plus 100 percent
excess. The remaining air enters the incinerator through the open
charging door during batch operation and through such places as expansion
joints and cracks around doors.
4. In-draft velocities in the combustion air ports (overfire, underfire, and
secondary) are assumed to be equal, with a velocity pressure of 0. 1
inch water column (equivalent to 1265 ft/min). The design of the draft
Theoretical Basis for General - Refuse Incinerator Design Recommendations 12-11
-------
system should give an available firebox draft of about 0. 1 inch water
column. Oversizing of adjustable air ports insures maintenance of
proper air induction.
The combustion calculations needed to determine weights, velocities, and
average temperatures of the products of combustion may be derived from standard
calculation procedures when the preceding assumptions are followed, using aver-
age gross heating values and theoretical air quantities. Inlet air areas in the
proportions designated are readily sized once the volumes of air and inlet velo-
cities are established. In practice, the minimum areas required should be over-
sized by the factor indicated in Table 12-1 in order to provide operational latitude.
Volume and temperature data of the products of combustion are the only
requirements for determining the cross-sectional flow areas of the respective
ports and chambers. Calculations for draft characteristics follow standard stack
design procedures common to all combustion engineering. The stack velocity
given for natural draft systems is in line with good practice and minimizes flow
losses in the stack.
The remainder of the essential calculations needed to design an incinerator
are based on substitution in the proper equations. Recommended grate loading,
grate area, and average arch height may be calculated or estimated from Figures
12-1 and 12-2. Proper length-to-width ratios may be determined and compared
with proposed values.
Supplementary computations are usually required in determining necessary
auxiliary-gas-burner sizes and auxiliary fuel supply line piping. Where moisture
content of the refuse is less than 10 percent by weight, auxiliary burners are not
usually required. Moisture content from 10 to 20 percent normally indicates the
necessity for installing mixed-chamber burners, and moisture percentages of
over 20 percent usually mean that ignition chamber burners must be included.
The criteria presented for incinerator design are applicable to the planning
of most combustible refuse burners. The allowable deviations given in Table 12-1
should be interpreted with discretion to avoid consistently high or low deviations
from the optimum values. Application of these factors to design evaluation must
be tempered by judgment and by an appreciation of the practical limitations of
construction and economy.
12-12 INCINERATION GUIDE
-------
12.7.2 Sample Calculations
The following example shows the mathematical calculations necessary to
design an incinerator.
Problem: Design a multiple-chamber incinerator to burn 100 pounds per hour
of paper containing 15 percent moisture.
Solution:
1. Composition of refuse:
Dry combustibles (100 Ib/hr) (0. 85) 85 Ib/hr
Moisture (100 Ib/hr) (0. 15) 15 Ib/hr
2. Gross heat of combustion:
From Table 14-4 in Appendix, the gross heating
value of dry paper is 7590 Btu/lb
(85 Ib/hr) (7590 Btu/lb) 645,200 Btu/hr
3. Heat losses:
From Table 14-4 in Appendix, 0. 56 Ib of water is
formed from the combustion of 1 Ib of dry paper.
Radiation, etc. (assume 20% loss)
(645,200 Btu/hr) (0.20) = 129,040 Btu/hr
Evaporation of contained moisture
(15 Ib/hr) (1060 Btu/lb) = 15, 900 Btu/hr
Evaporation of water from combustion
(0.56 Ib/lb) (85 Ib/hr) (1060 Btu/lb) 50,400 Btu/hr
Total 195,340 Btu/hr
4. Net heat:
645, 200 Btu/hr 195, 340 Btu/hr 449, 860 Btu/hr
5. Weight of products of combustion with 300%
excess air:
From Table 14-4 in Appendix, 21. 7 Ib of products
of combustion is formed from the combustion of
1 Ib of paper with 300% excess air.
Paper (85 Ib/hr) (21.7 Ib/lb) = 1844 Ib/hr
Water 15 Ib/hr = 15 Ib/hr
1859 Ib/hr
Theoretical Basis for General-Re fuse Incinerator Design Recommendations 12-13
-------
6. Average gas temperature:
The specific heat of the products of combustion
is approximately 0.26 Btu/lb-°F
Q
AT =
CpM
Where: AT = Temperature difference, °F
Q = Gross heat, Btu
Cp = Specific heat, Btu/lb-°F
M = Weight, Ib
T 449, 860 Btu/hr 930°F
(0.26 Btu/lb-°F) (1859 Ib/hr)
T = AT + 60°F
T = 930°F + 60°F = 990°F
7. Combustion air requirements:
Basis: Assume 300% excess air; 200% excess air
is admitted through the open charging door, and
leakage around doors, ports, and expansion joints.
From Table 14-4 in Appendix, 68. 05 ft3 of air is
theoretically necessary to burn 1 Ib of dry paper.
Total air required at 100% excess air:
(85 Ibs/hr) (68. 05 ft3/lb) (2) - 11, 580 ft3/hr
or 192. 8 ft3/min
or 3. 2 ft3/sec
8. Air port opening requirements at 0. 1 in. water column:
1265 ft/min is equivalent to a velocity pressure
of 0. 1 in.
Total = (192.8cfca)(144in2/ft2) = 22. 0 in2
1265 ft/mm
Air Supply from Table 12-1
Overfire, 70%; Underfire, 10%; Secondary, 20%
Overfire air port (0. 7) (22. 0 in2) = 15.4 in2
Underfire air port (0. 1)(22. 0 in2) = 2. 2 in2
Secondary air port (0.2) (22.0 in2) = 4.4 in2
9. Volume of products of combustion:
From Table 14-4 in Appendix, 283. 33 ft3 of products
12-14 INCINERATION GUIDE
-------
of combustion are formed from the combustion
of 1 Ib of paper with 300% excess air.
Basis: 60°F and 300% excess air
Paper (85 Ib/hr) (283. 33 ft3/lb) = 24, 080 ft3/hr
wa«. ..... ., . 379 ft3/lb-mol 316 ft.3/hr
Water (15 Ib/hr) lg lb/mol = 24, 396 ft^/hr
or 6. 8 ft3/sec
10. Volume of products of combustion through
flame port per second:
Total volume minus secondary air
6.8ft3/sec (3.2 ft3/sec) (0.20) = 6. 16 ft3/sec
11. Flame port area:
From Table 12-1, velocity is 55 ft/sec
(6.l6ft3/sec) (1560°R) 2
(55 ft/sec)(520°R)
12. Mixing chamber area:
From Table 12-1, velocity is 25 ft/sec
(6.8 ft3/sec) (1460°R) 2
(25 ft/sec) (520°R) ^_/o_i^
13. Curtain wall port area:
From Table 12-1, velocity is 20 ft/sec
(6.8ft3/sec) (1410°R) = 2
(20 ft/sec) (520°R) -^ -
14. Combustion chamber area:
From Table 12-1, velocity is 6-10 ft/sec, use 6 ft/sec
(6.8 ft3/sec) (1360°R) _ 2 , . 2
(6 ft/sec)(520°R) " ~^ -
\
15. Stack area:
From Table 12-1, velocity is <30 ft/sec, use 25 ft/sec
(6.8 ft3/sec) (1360°R) = 2
(25 ft/sec) (520°R) ~ : -
16. Grate area:
From Figure 12-1, the grate loading for average refuse
is 18 lb/ft2 - hr.
(100 Ib/hr) = 5 56 ft2
18 lb/ft2 hr -
Theoretical Basis for General - Refuse Incinerator Design Recommendations 12-15
-------
17. Arch height:
From Figure 12-2, the arch height - 27 in.
18. Stack height:
(Interpolated) From Table 12-1, Dt 0. 17 in. we
Dt 0.52PH^-^r->)
Where: D, Draft, in. we
P = Barometric pressure, psi
H = Height of stack above grates, ft
T = Ambient temperature, °R
T^ = Average stack temperature, °R
H ~
(0.52) (P)
TI
0 17**
H = - ' , - ; — r- 18.75 ft
*R. T. Kent, Mechanical Engineer's Handbook, pp. 6-104, llth Edition, John
Wiley and Sons, Inc., New York, 1936.
s=*Allowance is made for friction losses by assuming a value for theoretical draft
on the high side of the range.
12-16 INCIN ERATION GUIDE
-------
13 THEORETICAL BASIS FOR PATHOLOGICAL INCINERATOR
DESIGN RECOMMENDATIONS
13.1 SPECIAL CHARACTER OF TYPE 4 WASTE
Pathological waste is defined as whole, or parts of animal carcasses, ani-
mal organs, or organic animal waste. Chemically, this waste is composed princi-
pally of carbon, hydrogen, and oxygen. Slight amounts of many minerals, along
with a trace of nitrogen, are also present. Physically, this waste consists of
cellular material and fluids. The cells of interest are those of hair, fatty tissue,
and bone. The proportions of these different types of cells vary between different
types of animals. Blood and various other fluids in the organs are almost com-
pletely water.
The average chemical composition of whole animals, except for the propor-
tion of water present, is very similar in all types of animals. The proportion
of water present to the total weight of the animal varies quite widely between
different types of animals, and between various conditions of freshness or de-
composition of the animal material. Average chemical properties and combustion
data of pathological waste are given in Tables 13-1 and 13-2. The combustion data
have been found to provide good results when used in design calculations for almost
all pathological waste incinerators.
Table 13-1. COMPOSITION OF PATHOLOGICAL WASTEa
Constituent
Carbon
Hydrogen
Oxygen
Water
Nitrogen
Mineral (ash)
As charged,
% by weight
14.7
2.7
11.5
62.1
Trace
9.0
Ash-free combustible.
% by weight
50.8
9.35
39.85
-
aDry combustible empirical formula -
A principal factor to be considered in the design of pathological waste in-
cinerators is the release of fluids as the material is destroyed. Fluids are fre-
quently released, momentarily, in such quantities that they are not immediately
13-1
-------
Table 13-2. COMBUSTION DATA FOR PATHOLOGICAL WASTEa
(Based on 1 Ib dry ash-free combustible material)
Constituent
Theoretical air
40% sat. @ 60° F
Flue gas with C02
Theoretical air Ng
40% saturated HgO formed
H2O air
Products of combustion total
Gross heat of combustion
Quantity,
Ib
7.028
7.059
1.858
5.402
0.763
0.031
8.054
Volume,
scf
92.40
93.00
16.06
73.24
15.99
0.63
105.92
8,820 Btu/lb
aLos Angeles County Air Pollution Control District data.
evaporated. This release of fluids requires the use of a solid hearth, rather than
grates, in the ignition chamber of pathological incinerators. Pathological waste
does not form a fuel bed during incineration, and the passage of air through the
burning material is not required.
The relatively high percentage of moisture in each individual cell of path-
ological waste creates a difficult evaporation problem. The moisture must be
evaporated before the combustible animal tissue can be ignited, but moisture
evaporates only from those cells on or near the surface of the material exposed
to heat. Deeper lying tissue is almost completely insulated from the heat in the
chamber and is heated slowly. Evaporation of moisture from deeper cells, there-
fore, cannot take place until the destruction of the cellular material above them
exposes them to heat also.
While the heat of combustion of dry cellular material is considerable, this
material is present in such a small proportion, relative to the amount of water
present in tissue, that its heat of combustion is not sufficient to sustain combus-
tion. Auxiliary fuel must, therefore, be used to accomplish the necessary de-
hydration of pathological wastes.
13.2 DESIGN CALCULATIONS- GENERAL
Incinerator design calculations for pathological waste incinerators fall into
three general categories: (1) combustion calculations based upon the auxiliary
fuel heat input, waste composition, and assumed air requirements and heat losses;
(2) flow calculations based upon the products of combustion and assumed gas
temperatures; and (3) dimensional calculations based upon simple mensuration
13-2
INCINERATION GUIDE
-------
and empirical sizing equations. The factors to be used in these calculations for
pathological incinerator design are given in Tables 13-3 and 13-4.
Table 13-3. PATHOLOGICAL IGNITION CHAMBER DESIGN FACTORS
(Incinerator capacity = 25 to 200 Ib/hr)
Item
Hearth loading
Hearth length-to-width ratio
Arch height
Primary fuel
Gross heat release in ignition chamber
Specific heat of the products of combustion
including combustion of waste and natural
gas
Recommended value
See Figure 13-1
2
See Figure 13-2
See Figure 13-3
See Figure 13-4
0.29 Btu/lb-°F
Allowable
deviation
±10%
±20%
±20%
±10%
±20%
-
Table 13-4. GAS VELOCITIES AND DRAFT FOR PATHOLOGICAL INCINERATORS
WITH HOT GAS PASSAGE BELOW SOLID HEARTH
Item
Gas velocities
Flame port at 1600 °F
Mixing chamber at 1600 "F
Port at bottom of mixing chamber
at 1550 "F
Chamber below hearth at 1400°F
Port at bottom of combustion
chamber at 1400 °F
Combustion chamber at 1200 °F
Stack at 1000 °F
Draft
Combustion chamber
Ignition chamber
Unit
fps
fps
fps
fps
fps
fps
fps
in. we
in. we
Recommended
values
15
15
15
8
10
5
15
0.20 to 0.25a
0.05-0.10
Allowable
deviation
±20%
±20%
±20%
±50%
±20%
±50%
±25%
±10%
+ 0%
aDraft can be 0.20 in. we for incinerators with a cold hearth.
The following simplifying assumptions may be made:
1. The evaporation and burning rate, auxiliary fuel burning rate, and
average waste composition are taken as constant. Design parameters
should be based on that waste containing the highest percentage of
moisture that may be expected to be destroyed in the unit.
2. The average temperature of the combustion products is determined
through the heat loss calculation, using radiation and storage losses as
determined in Table 13-5.
Theoretical Basis for Pathological Incinerator Design Recommendations
13-3
-------
Table 13-5. IGNITION CHAMBER HEAT LOSSES
(Storage, convection, and radiation losses
during initial 90 minutes of pathological incineration operation)
Incinerator capacity
Ib/hr
25
50
100
200
Heat loss.
Btu/hr
125.000
180,000
278,000
390,000
. Heat loss,
%
36
33
30
25
3. The overall average gas temperature should be about 1500°F when cal-
culations are based on air for the combustible waste at 100 percent
excess of theoretical and air for the primary burner at 20 percent excess
of theoretical. The minimum temperature of the gases leaving the
ignition chamber should be 1600°F.
4. In-draft velocity in the air ports is assumed to be at 0. 1 inch water
column velocity pressure (1265 ft/min.).
5. The secondary air port is sized to provide 100% theoretical air for the
combustible material in the waste charged.
6. A primary air port of 5 in. /100 Ib of combustible waste is recommended.
The combustion calculations needed to determine weights and velocities of
the products of combustion along with average temperatures may be derived from
standard calculation procedures when the proceeding assumptions are followed.
The sizing of inlet air areas required is minimum and should be oversized in
practice to provide for operational latitude.
13.3 IGNITION CHAMBER PARAMETERS
Ignition chamber dimensions are determined by deriving hearth loading and
area, average arch height, and chamber volume from Figures 13-1 and 13-2, and
from the factors given in Table 13-3. The ignition chamber burner input capacity
may be determined from the curve given in Figure 13-3. Maximum heat release
rate, at the gross fuel heating value, in the whole incinerator will range from
20, 000 to 15, 000 Btu/hr-ft3 for sizes from 30 to 200 Ib/hr as shown in Figure,
13-4.
Length-to-width ratios for the hearth are not critical; however, to provide
for single-layer deposition of the material upon the hearth, a length-to-width ratio
of 1:2 is the most practical.
13-4 INCINERATION GUIDE
-------
200
150
LU
I-
z
o
I-
<
UJ
a-
100
50
100
90
80
70
60
50
40
20
10
^BURNER FLAMES NOT
DIRECTLY IMPINGING
ON ANIMAL
5 10 15 20
HEARTH AREA, ft2
Figure 13-1. Pathological incinerator cremation rate.
25
10
15
20
25
HEARTH AREA, ft2
Figure 13-2. Pathological incinerator arch height.
30
30
Theoretical Basis for Pathological Incinerator Design Recommendations
13-5
-------
25,000
CD
III
2 15,000
nj
u-
tH
< 10,000
s
D.
5,000
100,000
90,000
80,000
70,000
60,000
n
T 50,000
I
I 40,000
30,000
UJ
to
LU
20,000
10,000
10
V
*BURNER FLAMES NOT
DIRECTLY IMPINGING
ON ANIMAL
5 10 15 20
HEARTH AREA, ff2
Figure 13-3. Pathological incinerator fuel usage.
25
30
20
40
60
80 100
200
BATCH CREMATION RATE, Ib/hr
Figure 13-4. Heat release rates for pathological incinerators.
13-6
INCINERATION GUIDE
-------
The location of the gas burner in the ignition chamber is the most critical
aspect of the design of a pathological incinerator. The flames from the burner
must impinge directly on the material being incinerated, or excessive fuel con-
sumption will result. Figures 13-1 and 13-5 graphically illustrate this point.
I
at
o
Q
LU •-
z
o
I-
i
o:
U
*• BURNER FLAMES NOT
DIRECTLY IMPINGING
ON ANIMAL
10 IS 20
HEARTH AREA, ft2
Figure 13-5. Pathological incinerator cremation rate related to hearth area.
Further substantiation has been obtained from operating data on an incinera-
tor with high fuel consumption. Cremation rate can be increased 100 percent by
merely allowing a 4-inch layer of ash and bone residue to remain on the hearth.
The net effect was to raise the material being cremated into the direct path of the
burner flames.
To provide maximum penetration of heat into the animal matter being cre-
mated, a flame retention pressure burner, equipped with a blower, is required.
Of course, full safety controls should be provided. The larger incinerators re-
quire multiple burners in order to distribute the heat over the resultant larger
area.
Figure 13-3 shows that maximum utilization of fuel in a retort configuration
is reached with a hearth area of about 12 square feet. As the hearth area is
Theoretical Basis for Pathological Incinerator Design Recommendations
13-7
-------
increased or decreased, the fuel requirement is increased or decreased. The obvi-
ous conclusion is that the retort design should not be used for units larger than 22
square feet of hearth area. An analysis of the configuration reveals the reason
for this phenomenon and again confirms that burner location is of vital importance.
In the retort configuration, only one wall is available for burners to be conveniently
located, and inadequate flame distribution occurs in the larger hearth sizes.
13.4 SECONDARY COMBUSTION ZONE PARAMETERS
The velocity parameters stated in Table 13-4 are not too critical in these
units. The relatively small amount of combustible material in the waste does not
provide too severe a problem to achieve complete combustion. Particulate dis-
charge from these incinerators has been found to be very light (see Table 15-3),
and their principal design consideration is an effective rate of destruction of the
waste. Design consideration, however, must be given to one particular problem
in the burning of this waste material. Rapid volatilization results whenever fatty
tissue or hair is exposed to flame or high-temperature gases. The sudden volati-
lization causes a flooding of gases and vapors that is beyond the combustion
capacity of equipment designed for high velocities in the secondary combustion
zone on the basis of an average rate of operation. These periods of sudden volatili-
zation then result in considerable amounts of unburned gases and vapors issuing
from the stack or charging doorway. Design of the secondary combustion zone for
low-velocity gas movement at average volumes will provide for adequate combus-
tion even during the periods of abnormally high operating rates.
An additional auxiliary burner, having the heating capacity shown in Table
6-1 for secondary burners, located in the secondary combustion zone, is
necessary for these incinerators. The type and location of the auxiliary burners
are not nearly so critical as they are for the burner in the ignition chamber. Atmo-
spheric mixers equipped with full safety controls are adequate for incinerators
rated at 100 pounds per hour or less, but in larger units the nozzle mix type is
required in order to obtain optimum incineration.
The burner capacity need only be sufficient to maintain a 1600°F temperature
in the gases. To do this, the burner should be located so that the gas flowing from
the ignition chamber can first mix with secondary air before flowing through the
flame of the secondary burner. The secondary burner should also be located so
that the length of passage in the mixing chamber is sufficient to permit secondary
13-8 INCINERATION GUIDE
-------
combustion to occur. Its heating capacity should be that given in Table 6-1 for
secondary burners.
13.5 STACK DESIGN
Calculations for stack design should be based on a gas temperature of 1000°F.
Because design calculations are based on an average rate of operation, which is
sometimes exceeded, stack design velocity should be at, or below, 15 feet per
second. Stack height should be determined so as to provide a minimum available
draft of 0. 15 inches of water column. This is the minimum draft provision for
pathological incinerators. When a hot gas passage is required beneath the hearth,
the minimum available stack draft at the breeching should be increased by 10 per-
cent. This additional draft will compensate for the additional gas flow resistance
in the incinerator, caused by such a design.
13.6 PATHOLOGICAL SIDE CHAMBER
Figure 7-2 illustrates a retort for the burning of pathological waste added to
a standard multiple-chamber incinerator. When such construction is used, the
gases from the retort should pass into the rear of the ignition chamber of the stan-
dard incinerator. The design of the chamber is based on the same factors given
for the design of the ignition chamber of a pathological incinerator. The general-
refuse multiple-chamber design will be only negligibly influenced by the addition
of this unit under most circumstances. This design concept may only be used at
locations where the pathological waste material load occurs periodically, and in
small amounts, usually not more than 10 percent of the rated capacity of the stan-
dard incinerator. In order not to restrict the flow of the products of combustion
from the pathological chamber, the gas passage from the chamber should be de-
signed for about 10 feet per second.
13.7 ILLUSTRATIVE PROBLEM
Problem: Design an incinerator to dispose of 100 Ib/hr of dog bodies.
Design: Select a multiple-chamber retort-type incinerator with a hot-gas
passage below a solid hearth.
Solution:
1. Design features of ignition chamber:
From Figure 13-1 at 100 Ib/hr
Hearth area = 10 ft2
Theoretical Basis for Pathological Incinerator Design Recommendations 13-9
-------
From. Table 12-1, hearth dimensions:
Length-to-width ratio 2
Let w - width of hearth in ft.
(w) (2w) = hearth area
2w2 = 10 ft2
w = 2. 24 ft
Length 2w = 4. 48 ft
From Figure 13-2, arch height 26 in.
Total ignition chamber volume = 21.6 ft^
2. Capacity of primary burner:
From Figure 13-3, primary burner consumption is 7000 Btu/lb.
(7000 Btu/lb x 100 Ib/hr -=- 1100 Btu/scf = 635 scf/hr)
3. Composition by •weight of refuse:
Dry combustibles (100 Ib/hr) (0.29) = 29 Ib/hr
Contained moisture (100 Ib/hr) (0. 62) = 62 Ib/hr
Ash (100 Ib/hr) (0. 09) = 9 Ib/hr
Total 100 Ib/hr
4. Gross heat input:
From Table 13-2, the gross heating value of waste is 8, 820 Btu/lb. A
gross heating value of natural gas of 1100 Btu/scf may be assumed for
purposes of calculation.
Waste (29 Ib/hr) (8, 820 Btu/lb) = 256, 000 Btu/hr
Natural gas (635 ft3/hr) (1100 Btu/scf) = 700,000 Btu/hr
5. Heat losses:
a. From Table 13-5, gross heat losses by storage, conduction and
radiation are 29. 75 percent of gross heat input.
(0.2.975) (956, 000 Btu/hr) = 285, 000 Btu/hr
b. Evaporation of contained moisture at 60*F.
The heat of vaporization of water at 60°F is 1060 Btu/lb.
(62 Ib/hr) (1060 Btu/lb) = 65,700 Btu/hr
c. Evaporation of water formed from combustion of waste at 60°F.
From Table 13-2, combustion of 1 Ib of waste yields 0. 763 Ib of
wate r.
13-10 INCINERATION GUIDE
-------
(0.763 Ib/lb) (29 Ib/hr) (1060 Btu/lb) = 23,450 Btu/hr
d. Evaporation of water formed from combustion of natural gas at 60°F.
There is 0. 099 lb of water formed from combustion of 1 scf of natu-
ral gas. (Composition of gas and hence its combustion products will
vary with location.)
(0'09911sbc^ater)(635 scf/hr) (1060 Btu/scf) = 66,600 Btu/hr
e. Sensible heat in ash
Assume ash is equivalent in composition to calcium carbonate.
Average specific heat is 0.217 Btu/lb-"F.
H = WA (Cp)
-------
8. Average gas temperature:
Assume the average specific heat of combustion products is
0. 29Btu/lb °F
Q = (Wc) (Cp) (T2 T!)
Where: Q = Net heat available, Btu/hr
Wc = Weight of combustion products, Ib/hr
C_ = Average specific heat of combustion products , Btu/lb-°F
T£ = Average gas temperature, °F
TI = Initial temperature, °F
— -
T T +
X X
(Wc) (Cp)
This average temperature exceeds minimum design temperature of
1600°F; therefore, the primary burner has adequate capacity.
9. Secondary air port size:
Design secondary air port 100% oversize with an indraft velocity of
1255 ft/min at 0. 1 in. we velocity pressure.
From Table 13-2, 1 Ib of waste requires 93 scf of air.
(29 Ib/hr) (93. 0 scf/lb) 2697 ft3/hr
or 44. 93 ft3/min
or 0.749ft3/sec
(44. 93 ft3/min) (144 in. Z/ft2) (2) 2
155 ft/min ' ln'
10. Weight of maximum air through secondary port:
Assume that the density of air is 0. 0763 Ib/scf
(2) (2697 ft3/hr) (0. 0763 Ib/scf) 411. 5 Ib/hr
11. Heat required to raise maximum secondary air from 60° to 1600°F:
From Table 14-5, 396. 8 Btu is required to raise 1 Ib air from 60° to
1600°F.
(411. 5 Ib/hr) (396. 8 Btu/lb) = 164.400 Btu/hr
12. Natural gas required by secondary burner:
Design for combustion of natural gas with 20% excess air.
Taking the heating value of natural gas as 552 Btu/scf at 1600°F:
(164, 400 Btu/hr) + (552 Btu/scf) = 300 ft3/hr
13-12 INCINERATION GUIDE
-------
13. Volume of products of combustion:
a. Through flame port
From Table 13-2, combustion of 1 Ib waste with 100% excess air
will yield 198. 92 scf of combustion products. Combustion of 1 scf
natural gas with 20% excess air will yield 13. 53 scf of combustion
products. (Composition of gas and hence its combustion products
will vary with location. )
Waste (29 Ib/hr) (198. 92 scf/lb) = 5, 769 scf/hr
Water (63 Ib/hr) (379 scf/lb mole) = 1, 305 scf/hr
Natural gas (635 scf/hr) 'f ) = 8,550 scf/hr
Total volume of gases 15, 624 scf/hr
or 260 scf/min
or 4. 33 scf /sec
b. Through exit from mixing chamber
Design secondary burner for combustion at 20% excess air.
Products of combustion through flame port 15, 624 scf/hr
Products of combustion from secondary
burner (300 ft3/hr) (13. 53 scf /scf) 4, 060 scf/hr
Maximum air through secondary air port
(2) (2697 scf/hr) 5, 394 scf/hr
25, 078 scf/hr
or 418 scf/min
or 6. 97 scf/sec
14. Incinerator cross -sectional areas:
a. Flame port area
Design flame port for 15 ft/sec velocity at 1600°F.
(4.33 scf/sec) (2Q60°R) 2
-
Area = (15 ft/sec) (520'R)
b. Mixing chamber area
Design mixing chamber for 15 ft/ sec velocity at 1600°F.
(6.97 scf/sec) (2Q60°F) _ 2
Area (15 ft/sec) (520°R) ~ ^^-
c. Port area at bottom of mixing chamber
design port for 15 ft/sec velocity at 1550°F.
Theoretical Basis for Pathological Incinerator Design Recommendations 13-13
-------
Area - (6. 97 scf/sec) (2010°R)
Area ~ (15 ft/sec) (520°R)
d. Chamber area beneath hearth
Design chamber for 8 ft/sec velocity at 1400°F.
(6. 97 scf/sec) (1860°R) 2
A a -
Area " (8 ft/sec) (520°R) _
e. Port at bottom of combustion chamber
Design port for 10 ft/sec velocity at MOOT.
Area = (6.97 scf/sec) (1860°R) = 2 5Q ft2
(10 ft/sec) (520°R) -1 -
f. Combustion chamber
Design combustion chamber of 5 ft/sec velocity at 1200 °F.
Area - (6. 97 scf/sec) (1660°R) _ 2
Area ~ (5 ft/sec) (520°R) ~ 4i4b_tt_
g. Stack
Design stack for 15 ft/sec velocity at 1000°F.
. (6.97 scf/sec) (1460°F) _ 2
Area (15 ft/sec) (520°R) ~ '
15. Stack height:
Design stack for a draft of 0. 20 in. we in the combustion chamber.
Stack height
/
1
Dt = 0.52 PH--
Where D-j- = Draft, in. we
T - Ambient air temperature, "R
TI Average stack gas temperature, °R'
P Atmospheric pressure, Ib/in. ^
H = Stack height, ft
_ (0.20)
H
(0.52) (14. 7) _
1460>
*Allowance is made for frictional losses by assuming a high value for theoretical
draft.
13-14 INCINERATION GUIDE
-------
14 APPENDIX
14.1 COSTS OF INCINERATORS AND SCRUBBERS
Approximate costs of recommended multiple-chamber incinerators and
scrubbers are given in Table 14-1.
A number of factors affect the construction cost of multiple-chamber incin-
erators throughout the United States. The factors that normally contribute to a
variation usually include the keenness of local competition, differences in labor
costs, specific type of construction used, and the appurtenances specified by the
buyer. In general, material costs are essentially the same throughout the country
and do not normally contribute to a variation in the original cost.
Appurtenances such as mechanical grates, continuous ash removal systems,
and mechanical charging mechanisms may also add as much as 150 to 200 percent
to the cost of an incinerator. The need for such items is usually based upon the
size of the incinerator, as well as the operational manpower saved by their instal-
lation.
In general, the approximate cost of multiple-chamber incinerators presented
in Table 14- 1 should be within 15 percent of the basic cost of the incinerator any-
where in the United States.
14.2 ADDITIONAL INFORMATION
Information on emissions from general-refuse and pathological incinerators
not equipped with gas washers is given in Tables 14-2 and 14-3, respectively.
Chemical properties and combustion data for paper, wood, and garbage are
presented in Table 14-4. Table 14-5 gives enthalpies of gases from 60°F in Btu
per pound of gas.
A list of addresses of regional air pollution control directors is given in
Table 14-6.
14-1
-------
Table 14-1. APPROXIMATE COSTS OF RECOMMENDED MULTIPLE-CHAMBER
INCINERATORS AND SCRUBBERS IN 1968a
"Size" of
incinerator,
Ib/hr
50
100
150
250
500
750
1000
1500
2000
General-refuse
incinerators
$ 1.200
1,700
2.000
2.700
5,000
9.500
12,500
20.000
25.000
Scrubbers^
$ 2,200
3,000
3.600
4.400
6,200
7,600
8.800
11,200
13,200
Pathological
incinerators
$2.000
2.700
4.000
5.500C
alncinerator costs are exclusive of foundations.
^Scrubber costs are exclusive of foundations but include reasonable utility connections.
cFor a 200-pound-per-hour incinerator.
14-2
INCINERATION GUIDE
-------
I
s
'
Table 14-2. EMISSIONS FROM GENERAL-REFUSE INCINERATORS WITHOUT GAS WASHERS
Operational conditions
Incinerator capacity, Ib/hr
Weight of refuse burned, Ib
Test conditions: Testing period, min
Burning rate; Ib/hr burned
Capacity, % rated
Charging rate, Ib/batch
min/batch
Composition of refuse charged:
% paper
% garbage
% wood
Auxiliary fuel:
Primary chamber burner, scfh
Mixing chamber burner, scfh
Combustion air:
Primary air-overfire % total supply
Primary air-underfire % total supply
Secondary air-mixing chamber % total supply
Stack:
Flow rate, scfm
Moisture at stack conditions, %
Orsat analysis - % CC>2
%0g
%CO
%N2
Stack temperature, °F
Particulates:
grains/scf of stack gas
grains /scf of stack gas @ 12% COg
(COg from refuse only)
Smoke emissions:
Maximum opacity of stack gases, %
Duration of smoke of maximum opacity, min
la
Normal
no
burners
50
30
38
47
95
2-4
2-4
100
0
0
None
None
85
15
0
174
8.3
4.8
13.8
0.0
81.4
1160
0.0987
0.270
10
1
Ib
Normal
with
burners
50
26
34
46
92
2-4
2-4
69
3)
0
165
165
45
10
45
193
13-2
6.4
6.3
0.0
87.3
1475
0.058
0.300
0
0
2
Normal
250
203
66
185
74
10-15
5
85
15
0
185
800
40
10
50
480
14.9
9.3
4-1
0.0
86.6
1600
0.0852
0.254
80
1.5
3
Normal
750
713
60
713
95
20
2
71
17
12
None
1125
79
7
14
1970
10.8
6.0
12.6
0.0
81.4
910
0.075
0.205
45
1.0
Test number
4 -
Normal
1000
770
55
870
88
75
6-7
83
17
0
None
2850
50
20
30
2190
12-0
7.4
9.9
0.0
82-7
1560
0.083
0.248
10
2.5
5
Normal
850
650
60
650
76
50- 100
3-5
100
0
0
None
822
80
10
10
6300
4.4
2.4
18.0
0.0
79.6
872
0.047
0.274
20
1
6
Normal
1000
820
60
820
82
40
3
100
0
0
None
1390
54
7
39
2700
7.8
5.6
13.9
0.0
80.0
1080
0.060
0.140
0
0
7
Normal
2500
3825
101
2300
92
400
10
100
0
0
None
Oil-2.5gph
60
3
37
13400
5.7
2.2
18.3
0.0
79.5
N.A.
0.0197
0.113
15
9
8
Normal
6000
6500
60
100
650
10
65
0
35
None
None
70
10
20
27500
11.9
6.3
9.4
0.0
84.3
N.A.
0.0920
0.200
0
0
-------
Table 14-3. EMISSIONS FROM PATHOLOGICAL INCINERATORS WITHOUT GAS WASHERS
Type of waste
Batch destruction rate to
dry bone and ash, Ib/hr
Participates
gr/scf
gr/scf at 12% COg
(COg from refuse only)
Organic acids,
gr/scf
Ib/hr
Ib/ton
Aldehydes,
gr/sof
Ib/hr
Ib/ton
Nitrogen oxides,
ppm
Ib/hr
Ib/ton
Stack emissions:
Opacity, %
Time, min
Auxiliary fuel:
Primary, scfh
Mixing, scfh
Gas flow, scfm
Gas temperature, °F
Stack gases, %
C02
00
Ng
HgO
Cost of incinerator, $
Test number
1
Human
tissue
19.2
0.014
0.240
0.006
0.010
1.04
N. A.
N. A.
N. A.
42.7
0.085
8.86
0
190
185
260
410
3-4
12.5
0.0009
74.0
10.1
2400
8
Human
tissue
64
0.017
0.400
0.0008
0.003
0.093
0.008
0.076
2.37
35
0.29
9.05
0
700
230
1150
307
2.1
16.5
0.0
74.8
6.6
2500
3
Animals
62
0.032
0.183
0.010
0.034
1.10
0.013
0.041
1.32
134
0.37
12.0
0
580
170
380
590
5.6
9.8
0.004
71.5
18.1
4250
4
Animals
35
0.015
0.106
N. A.
N. A.
N. A.
0.004
0.014
0.80
111
0.29
16.6
0
^
600
800
370
950
6.3
7.7
0.0
71.9
14.1
1300
5
Animals
99
0.0936
0.295
0.013
0.050
1.01
0.006
0.020
0.40
131
0.099
2.00
0
640
260
450
800
7.6
4.8
0.02
67.2
20.4
2700
6
Animals
137
0.013
0-260
0.0033
0.075
1.10
0.0032
0.072
1.05
60
1.2
17.5
0
800
600
2640
346
1.6
17.7
0.0
75.5
5.2
3200
7
Animals
149
0.024
0.240
0.0018
0.012
0.161
0.012
0.082
1.10
165
0.94
12.6
0
1020
480
780
1020
4.9
10.8
0.0
71.2
13.1
3000
8
Animals
160
0.0202
0.135
0.0002
0.002
0.025
0.010
0.12
1.50
102
1.1
13.7
0
1800
500
1400
910
5.0
10.8
0.0
73-1
11.1
6000
I
i
-------
Table 14-4. CHEMICAL PROPERTIES AND COMBUSTION DATA FOR PAPER,
WOOD, AND GARBAGE
Analysis, %
Carbon
Hydrogen
Nitrogen
Oxygen
Ash
Gross heating value
(dry •basis), Btu/lb
Constituent
(based on 1 Ib)
Theoretical air
Theoretical air
40% sat. @ 60°F
Flue gas COg
with Ng
theor. air HgO formed
HgO (air)
Total
Flue gas o
with % 50.0
excess 100.0
air as 150.0
indicated 200.0
300.0
Sulfite
papera
44.34
6.27
48.39
1.00
7590
Cubic
feet
67.58
68.05
13.993
53.401
11.787
0.471
79.652
79.65
113.44
147.23
181.26
215.28
283.33
Pounds
5.165
5.188
1.625
3.947
0.560
0.023
6.155
6.16
8.74
11.32
13.91
16.51
21.70
Average
woodD
49.56
6.11
0.07
43.83
0.42
8517
Cubic
feet
77.30
77.84
15.641
61.104
11.487
0.539
88.771
88.77
127.42
166.07
204.99
243.91
321.75
Pounds
5.909
5.935
1.816
4.517
0.546
0.026
6.905
6.91
9.86
12.81
15.79
18.75
24.68
Douglas
firc
52.30
6.30
0.10
40.50
0.80
9050
Cubic
feet
84.16
84.75
16.51
66.53
11.84
0.587
95.467
95.47
137.55
179.63
222.01
264.38
349.13
Pounds
6.433
6-461
1.917
4.918
0.563
0.028
7.426
7.43
10.64
13.86
17.09
20-12
26.58
Garbaged
52.78
6.27
39-95
1.00
8820
Cubic
feet Pounds
85.12 6.507
85-72 6.536
16.668 1-935
67.234 4-976
11.880 0.564
0-593 0.029
96.375 7.495
96.38 7.50
139.24 10.77
182.00 14.04
224.86 17.21
267.72 20.58
353.44 27-12
aSulfite paper constituents: Cellulose
Hemicellulose
Lignin
Resin
Ash
C20H30°2
84%
8
6
2
1
bKent, R. T., Mechanical Engineer's Handbook, nth Edition, John Wiley and Sons, New York, 1936, pp. 6-104-
cKent, R. T., Mechanical Engineer's Handbook, 12 Edition, John Wiley and Sons, New York, 1961, pp. 2-40.
^Estimated on dry basis.
Appendix
14-5
-------
Table 14-5. ENTHALPIES OF GASES FROM 60 °F
(Btu/lb of gas)
Temp.. °F
100
150
200
250
300
350
400
450
500
550
600
700
800
900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
2200
2300
2400
2500
3000
3500
CO2
5.8
17.6
29.3
40.3
51.3
63.1
74.9
87.0
99.1
111.8
124.5
150.2
176.8
204.1
231.9
260.2
289.0
318.0
347.6
377.6
407.8
438.2
469.1
500.1
531.4
562.8
594.3
626.2
658.2
690-2
852.3
1017.4
N2
6.4
20.6
34.8
47.7
59-8
73.3
84.9
97.5
110.1
122.9
135.6
161.4
187.4
213.8
240.5
267.5
294.9
326.1
350.5
378.7
407.3
435.9
464.8
493.7
523.0
552.7
582.0
612.3
642.3
672.3
823.8
978.0
H20
17.8
40.3
62.7
85.5
108.2
131.3
154.3
177.7
201.0
224.8
248.7
297.1
346.4
396.7
447.7
499.7
552.9
606.8
661.3
717.6
774.2
831.4
889.8
948.7
1003.1
1069.2
1130.3
1192.6
1256.8
1318.1
1640.2
1975.4
°2
8.8
19.8
30.9
42.1
53.4
64.8
76.2
87.8
99.5
111.3
123.2
147.2
171.7
196.5
221.6
247.0
272.7
298.5
324.6
350.8
377.3
408.7
430.4
457.3
484.5
511.4
538.6
566.1
593.5
621.0
760.1
901.7
Air
9.6
21.6
33.6
45.7
57.8
70.0
82.1
94.4
106.7
119.2
131.6
156.7
182.2
211.4
234.1
260.5
287.2
314.2
341.5
369.0
396.8
424.6
452.9
481.2
509.5
538.1
567.1
596.1
625.0
654.3
802.3
950.3
Source of data: Kobe, K. A. and Long, E. G., Petroleum Refiner, 28, No. 11, 127, (1949).
Note: The enthalpies tabulated for HgO represent a gaseous system, and the enthalpies do not
include the latent heat of vaporization. It is recommended that the latent heat of vaporization
at 60°F (1059.9 Btu/lb) be used where necessary.
14-6
INCINERATION GUIDE
-------
Table 14-6. ADDRESSES OF REGIONAL AIR POLLUTION CONTROL DIRECTORS3
Regions
States and Addresses
Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island and Vermont
DHEW, J. F. Kennedy Federal Building, Boston, Massachusetts 02203
II
Delaware, New Jersey, New York, and Pennsylvania
DHEW - PHS, Federal Office Building, 26 Federal Plaza (Foley Square), New York. N. Y. 10007
III
District of Columbia, Kentucky, Maryland, North Carolina, Virginia, West Virginia, Puerto Rico,
and Virgin Islands
DHEW, 220 Seventh Street, N.E., Charlottesville, Virginia 22901
IV
Alabama, Florida, Georgia, Mississippi, South Carolina and Tennessee
DHEW, Room 404, 50 Seventh Street, N.E., Atlanta, Georgia 30323
V
Illinois, Indiana, Michigan, Ohio, and Wisconsin
DHEW, Room 712, New Post Office Building, 433 W. Van Buren St., Chicago, Illinois 60607
VI
Iowa, Kansas, Minnesota, Missouri, Nebraska, North Dakota, and South Dakota
DHEW, 601 E. 12th Street, Kansas City, Missouri 64106
VII
Arkansas, Louisiana, New Mexico, Oklahoma, and Texas
DHEW, 1114 Commerce Street, Dallas, Texas 75202
VIII
Colorado, Idaho, Montana, Utah, and Wyoming
DHEW, Room 8026, Federal Office Building, 19th and Stout Street, Denver, Colorado 80202
IX
Alaska, Arizona, California, Hawaii, Nevada, Oregon, Washington, Guam, and American Samoa
DHEW, 50 Fulton Street, Federal Office Building, San Francisco, California 94102
Correspondence should be addressed to the Regional Air Pollution Control Director, National Air Pollution
Control Administration, at the appropriate address given above.
Appendix
14-7
-------
15 ACKNOWLEDGMENTS
Although many sources of information were consulted in preparing this
Guide, the principal source was the Los Angeles County Air Pollution Control
District. Important and constructive revisions to the Guide were made following
review by members of the Incinerator Institute of America.
15-1
-------
16 BIBLIOGRAPHY
1. Code of Federal Regulations, Subchapter F, Title 42, Part 76.
2. I.I. A. Standards, Incinerator Institute of America, New York, New York,
November 1968.
3. Contract Number PH27-66-B9 with the Los Angeles County Air Pollution
Control District, 1966.
4. Multiple-Chamber Incinerator Design Standards for L/os Angeles County,
J. E. Williamson et al. Los Angeles County Air Pollution Control District,
October I960.
5. Source Testing Manual, Los Angeles County Air Pollution Control District,
November 1963.
6. Air Pollution Effects of Incinerator Firing Practices and Combustion Air
Distribution. A. M. Rose, Jr. , et al. Journal of the Air Pollution Control
Association, February 1959.
7. Cincinnati Ordinance No. 119-1965, Division J, Section 2509-8.
8. Stack Gas Sampling Improved and Simplified with New Equipment. W. S.
Smith, et al. Presented at the 60th Annual Meeting of the Air Pollution
Control Association, June 1967. Cleveland, Ohio.
9. Specifications for Incineration Testing at Federal Facilities. U.S. Depart-
ment of Health, Education, and Welfare, Public Health Service, Bureau of
Disease Prevention and Environmental Control, National Center for Air Pollu-
tion, Abatement Program. Durham, N. C. October 1967.
10. Addendum to Specifications for Incinerator Testing at Federal Facilities.
U. S. Department of Health, Education, and Welfare, Public Health Service,
Bureau of Disease Prevention and Environmental Control, National Center for
Air Pollution Control. Durham, N. C. December 6, 1967.
11. Standard For Incinerators and Rubbish Handling No. 82. National Fire Pro-
tection Association, 60 Batterymarch Street, Boston, Massachusetts. May
I960.
12. Standard for the Installation of Air Conditioning and Ventilating Systems No.
90A. National Fire Protection Association, 60 Batterymarch Street, Boston,
Massachusetts, 1967.
13. Code for the Installation of Heat Producing Appliances, Heating, Ventilating,
Air Conditioning, Blower and Exhaust Systems, American Insurance Associa-
tion, 85 John Street, New York, New York, 1967.
14. Standard for Fire Doors and Windows, No. 80, National Fire Protection
Association, 60 Batterymarch Street, Boston, Massachusetts, 1967.
15. Standard for the Installation of Oil Burning Equipment No. 31, National Fire
Protection Association, 60 Batterymarch Street, Boston, Massachusetts, 1965.
16-1
-------
16. Standard for the Installation of Gas Appliances and Gas Piping No. 54, National
Fire Protection Association, 60 Batterymarch Street, Boston, Massachusetts,
1964.
17. 1967 Book of ASTM Standards, Part 13, Refractories, Glass, and Other
Ceramic Materials; Manufactured Carbon and Graphite Products, American
Society for Testing and Materials, Philadelphia, Pennsylvania, April 1967.
18. 1967 Book of ASTM Standards, Part 14, Thermal Insulation; Acoustical
Materials; Joint Sealants; Fire Tests; and Building Constructions, American
Society for Testing and Materials, Philadelphia, Pennsylvania, August 1968.
19. Incinerator Institute of America, Bulletin T-6 Incinerator Testing, August
1968.
S. GOVERNMENT PRINTING OFFICE : 1969—395-977/20
!6_z INCINERATION GUIDE
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