ROBERT A. TAFT WATER RESEARCH CENTER
REPORT NO. TWRC-10
MATHEMATICAL MODEL
OF
SEWAGE SLUDGE FLUIDIZED BED
INCINERATOR CAPACITIES AND COSTS
ADVANCED WASTE TREATMENT RESEARCH LABORATORY-X
U.S. DEPARTMENT OF THE INTERIOR
FEDERAL WATER POLLUTION CONTROL ADMINISTRATION
OHIO BAS/N REG/ON
Cincinnati, Ohio
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ERRATA SHEET
Page 3
Add "HF - Height of freeboard"
Page 9
After equation (6) add
"Where PVS is the weight of volatile solids in the sludge"
Page 9
After equation (7) add
"Where PH2(j) is the weight percent water in the sludge"
Page 10
The equations at the top of the page should read
QSL = QS(P^)VS)/PS (13)
and _
AIRCP = 4.76 (XF+Y)(M)(C )(T)
Page 10
After equation (15) add
"Where QFU is the higher heat of combustion of fuel"
Page 10
Equation (21) should read
"THCP = SUMQ/PS
Where SUMQ has the units of BTU and THCP has the units of
BTU/lbs sludge"
Page 11
The first sentence should read
"The fuel rate and thus heat input to the incinerator are
adjusted by means of the mole multiplier FM"
Page 11
In the section entitled "Limitations of the Theoretical
Determination of BAF and QF", paragraph 1, delete second
sentence. Third sentence should read: "When complete
combustion equations are applied to data derived from an
elemental analysis, an exact calculation of the air
required for combustion is attainable".
Page 11
Second paragraph should read: "The heating value of a sludge
could be calculated based on elemental analysis. A bomb
calorimeter could be employed in the laboratory to obtain
the actual heating value (QS). Because of the unavailability
of data no attempt was made to calculate QS in the computer
program".
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- 2 -
Page 11
Paragraph 4, line 5, change the word "Three" to "Two".
Page 11
Paragraph 4, line 9, change the word "fourth" to "third".
Page 12
Paragraph 3, second sentence should read
"The maximum heat rate (BTU/hr) that can be obtained from
the exhaust products without causing undue condensation is
when the exhaust products are cooled from 1400°F to 400°F
in the preheater. The heat transferred per hour is
PC, . (aEMcaP) (Z7)
Page 13
Equation (30) should read
"SUMS = (QSL + QFP + QL)CAP (3O)
where SUMQ in equation (30) is the heat input to the reactor,
BTU/hr and QL is the heat loss from the reactor which must be
generated by the heat of combustion, BTU/# Sludge.
Page 13
Paragraph 4, delete the last sentence. Add in its place the
following sentence: "All incinerators have the same sand
depth within reasonable limits (approximately 5 to 6 feet
static level)".
Page 16
In paragraph following equation (38), second sentence, delete
"somewhat" .
Page 24
In the section entitled "Sand Loss Rate" add at the end of the
first paragraph: "The sand that was used during the course of
this study was obtained from a local supplier with the require-
ments that the sand have a high resistance to abrasion and
fluidize at reasonable air flow velocities through the grid."
Page 45 ,
In the section entitled "Reactor Sizing Limit ", add footnote
to read: "Dorr-Oliver has informed the authors that they have
industrial calciner units in operation with diameters of 45
feet" .
Page 61
Delete section entitled "Method of Rating" .
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- 3 -
Page o 7
Delete SUNKJ and its defination and substitute
"SlMJ = Total heat content of exhaust products based on
specific heats, BTU for page 10, equation 21.
SUM3 = Total heat input to reactor, BTU/hr for page 13.
equations 30 and 31"
Add to the defination of the term THCP:
"where SUMQ is obtained from page 10, equation 21".
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MATHEMATICAL MODEL OF SEWAGE SLUDGE FLUIDIZED
BED INCINERATOR CAPACITIES AND COSTS
by
G. J. Ducar and P. Levin
for
The Advanced Waste Treatment Research Laboratory
Robert A. Taft Water Research Center
This report is submitted in
fulfillment of Contract No.
1U-12-U15 between the Federal
Water Pollution Control Admin-
istration and General American
Transpoitation Corporation.
U. S. Department of the Interior
Federal Water Pollution Control Administration
Cincinnati, Ohio
September, 1969
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FOREWORD
In its assigned function as the Nation's principal na-
tural resource agency, the United States Department of the
Interior bears a special obligation to ensure that our ex-
pendable resources are conserved } that renewable resources
are managed to produce optimum yields , and that all resources
contribute their full measure to the progress, prosperity,
and security of America — now and in the future.
This series of reports has been established to present
the results of intramural and contract research studies car-
ried out under the guidance of the technical staff of the
FWPCA Robert A. Taft Water Research Center for the pqrp
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TABLE OF CONTENTS
PAGE
FOREWORD
ABSTRACT
INTRODUCTION if
DESCRIPTION OF SYSTEMS ANALYZED 3
Terminology 2
System Components and Operation 3
METHOD OF APPROACH 6
Information and Data Gathering 6
Literature Survey 6
Manufacturers' Survey 6
Field Survey °
RESULTS 7
Data Collected 7
Equations Developed 7
Theoretical vs. Pilot Plant Data 7
Limitations of the Theoretical
Determination,of BAF and QF J-B
Air Preheater Sizing 13
Sizing the Reactor ^
System Power Requirements 2^
Sand Loss Rate 2f*
Carbon and Hydrogen Content of Fue^s. 24
System Costs 2^
Cost Structure ?T
System Cost Less Air Preheater 26
Air Preheater Cost 30
Total Equipment Cost 30
Installation Fee 30
Consulting Engineers' Fee 33
Total System Cost 33,
Air Preheater1 Fuel Savings 33
iii
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TABLE OF CONTENTS (CONTINUED)
PAGE
Annual Operating Cost 33
Annual Maintenance Cost 3^
Annual Operating and Maintenance Cost 35
Scrubber Costs 35
Cost of Installations 37
COMPUTER PROGRAM 39
Listing of Program 39
Flow Chart 1*3
How to Use the Computer Program kk
Options in the Selection of Input Data kk
Reactor Sizing Limit 45
Air Preheater Option U5
Data Input and Output U5
CONCLUSIONS AND RECOMMENDATIONS 6l
Performance of the System 6l
Method of Rating 6l
Factors Influencing Operating Costs 62
Accuracy of the Equations Developed 62
Lime Recalcination 62
TERMINOLOGY 63
REFERENCES 68
BIBLIOGRAPHY 69
PATENTS FOUND ON FLUIDIZED BED INCINERATOR EQUIPMENT 72
IV
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ABSTRACT
This report describes the development of a computer program to evalute
sewage sludge fluidized bed incineration systems. Data for the program was
collected from manufacturers, a literature survey and field trips to operating
installations. Most of the data was obtained from the field because of the
lack of available information from the other sources.
More than fifty correlation relationships were attempted before the
necessary data could be reasonably represented. Equations were developed for
the least square curves which fitted the data best. These equations were
used as the basis for the computer program developed to size some of the
major components and to estimate capital, operating and maintenance costs
for the fluidized bed incineration system.
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INTRODUCTION
Domestic and industrial sewage wastes ar ; mixed with water and piped Lo
a sev/age treatment plant. To reclaim and purify the water mixed with the
sewage, many processes can be used. When attempts are made to separate the
suspended solids from the water (dewatering), only a portion of the separa-
tion can "be achieved. The resulting effluents from the dewatering device
are a stream of turbid water and a stream composed of approximately IVJo
water and 30$ solids by weight (sludge). This sludge must be disposed of in
some sanitary way (ultimate disposal).
The cost of the ultimate disposal of solids generated at waste water
treatment plants can amount to 25 to 50$ of the construction and operating
costs of an entire waste treatment plant. Incineration of this sludge reduces
the volume of wastes to be disposed of by approximately 9°& &nd produces ash
and flue gas. Incineration is often the only method available to dispose of
sludge.
A recently developed incineration technique uses a fluidized bed qf inert
material capable of completely oxidizing all the organic material in the sludge.
This technique is based on the principle, long used for processing in the
chemical industry, that when solids are suspended in an upward-moving stream
of gases, the mixture possesses the characteristics of a liquid. The properties
of this fluidized bed in terms of mixing and heat transfer can be utilized to
effect both rapid mixing and almost instantaneous incineration of the organic
material in sludge.
The purpose of this study was to develop a mathematical model of fluidiaed
bed incinerators for burning sewage sludge. The model was to be composed of
equations which represented the incineration equipment and process. Such a
model would help FWPCA determine approximate sizing of the principal reaction
vessels and associated equipment, the amount of fuel and power required, and
estimates of the capital, operating, and maintenance costs for fluidized bed
incineration systems to be funded. The necessary equations were developed
from data obtained in the literature, and surveys conducted at equipment
manufacturers plants and in the field.
It was not possible to obtain itemized cost breakdowns for each of the
system components. Therefore, capital costs were developed on a systems
basis:
1) The system costs developed in this program include the components
of Figure 2.
2) The stream vector required for input to this program is to repre-
sent the sludge cake leaving the centrifuge.
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DESCRIPTION OF SYSTEMS ANALYZED
Terminology
A schematic of the reactor or combustion chamber which is the heart of
the fluidized bed incineration system is shown in Figure 1 which illustrates
the parameters related directly to the reactor and the various regions of the
reactor. The lower section of the reactor consists of an air plenum and a
grid for sand support. Above the grid is the sand bed (tapered portion of
reactor). When air is blown through the sand, it is fluidized (thus expanding
the sand). The section above the expanded sand bed is termed the area free-
board. The terminology shown in Figure 1 is specifically related to the
reactor vessel. However, this program required a more comprehensive system
analysis.
System Components and Operation
The system components included in this study are shown in Figure 2, which
illustrates the complete fluidized bed incineration system usually purchased as
a package. This system was used as the basis for including equipment in the
study because cost data collected included all of the components, as a group,
as shown in Figure 2. The waste feed and dewatering system usually consists
of centrifuges, belt conveyors and a screw feeder at the reactor. Since it was
not possible to get costs for the individual components, it was necessary to
develop cost information for the total system.
Sludge is dewatered in a centrifuge or vacuum filter. Costs developed
for this program are based on systems using a centrifuge. The sludge cake is
conveyed directly into the reactor by means of a special screw feeder. Some-
times the screw feeder is connected to flexible reinforced ducting through
which the sludge is conveyed, to the reactor. Air from the blower is passed
into a plenum and through a sand-bed supporting grid. This grid also serves
to distribute the air so that fairly uniform fluidization of the sand occurs
above the grid. The sand bed is maintained at temperatures between 1220° and
l800°F. (The exact maximum and minimum temperatures attainable are determined
by the temperature at which essentially complete combustion occurs.) Bed
temperature is controlled by fuel regulations, water sprays, and excess air
flow. The sludge is burned almost completely in the bed, but because of the
mixing characteristics of the fluidized bed, there is considerable burning
above the sand bed in some instances. Therefore, in some instances, the
above-bed temperature in the freeboard area may be several hundred degrees
higher than the bed temperature.
The freeboard serves to keep the sand from being carried out of the
reactor with the exhaust products and also serves as a secondary combustion
chamber. The exhaust products leave the freeboard section and pass through
an air preheater (if one is used). The gases are then cooled to approximately
l£0°F by a water spray before entering the scrubber where the fly ash and
small sand particles, carried out of the reactor with the flue gas, are
removed from the gas stream.
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TO STACK
A)K SUPPLY'—0
ORH - Overall Reactor Height
VE - Volume Expanded
VS - Volume Static
EOT - Diameter Freeboard
AF - Area Freeboard
DS - Diameter Static
HS - Height Static
AG - Area Grid
DG - Diameter Grid
HP - Height Plenum
HE - Height Expanded
Figure 1 REACTOR TERMINOLOGY
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The warmup burner, shown at the side of the freeboard in Figure 2, is used
to preheat the reactor to 1000°F before the bed burners are ignited. Alterna-
tively, the preheat burner may be located in the plenum to preheat the incoming
combustion air. The warmup burner is usually extinguished when the bed burners
are ignited.
The air supply is controlled so that approximately ^ Op is present in
the exhaust gases.
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S PUANT
^S- CENTR1FU&E
'••— CENTRATE
WASTE PS.E.D ^
f DEVWATERIWG. SYSTEM
V^
SCREW FEEDER
PLE.WUV*
BL.fl \AJCR.
Figure 2
SYSTEM COKAPCIWEMTS IMCLUOEO ^^«J
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METHOD OF APPROACH
As the initial step in this program, it was necessary to secure complete
representative data on the fluidized bed incinerator. The procedure used is
described below.
Information and Data Gathering
Literature Survey
A review of the literature revealed that the first fluidized bed inciner-
ator in the U.S.A. was installed in 1962 in Lynwood, Washington. Information
was also available on one or two other installations; however, it soon became
apparent that there was insufficient information available in the literature
to generate a model. However, since about 30 new installations were either
recently placed on stream or were in the design stage, a survey of equipment
manufacturers was initiated.
Manufacturers Survey
A letter of inquiry together with an information sheet was directed to
manufacturers advising that we were engaged in an FWPCA program and requesting
cooperation in securing the necessary information. Very little data were
obtained from manufacturers.
Field Survey
At this point, it became apparent that the necessary information could
only be obtained from field installations. Since a number of installations had
been financed under the construction grants program of FWPCA, visits were made
to selected FWPCA regional offices to secure design and cost data from plans
submitted for a construction grant. Visits were made to regionel offices in
Chicago, Kansas City, Boston, San Francisco, and Edison, N. J.
Subsequently, visits were made to treatment plants selected on the basis
of capacity, location and period of operation: Sheboygan, Wisconsin; Kansas
City, Kansas; Bars tow, California; Port Heuneme, California; East Cliff,
Sanitary District, Santa Cruz, California; Foster City, California; Fairfield
Suisan City, California; Liberty, New York; Hazelton, Pa.; and Pleasantville,
N. J.
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RESULTS
Data Collected.
A summary of the data collected during the field survey is presented in
Tables I and II.
The equipment sizing and cost data are very reliable since they were
obtained from visual inspection or files. However, the data for operating
costs (fuel consumption, power consumption, operator costs, etc.) were not
readily available, since accurate operating records were not generally main-
tained at the plants.
Since the plants surveyed were purchased at different times, a standard
cost reference date of February, 1968 was chosen for this program. All unit
prices were corrected to February, 1968 prices, using the Department of the
Interior cost index for sewage treatment plant costs as presented in the
Engineering News-Record Magazine.
Equations Developed
Equations were developed from this data and an FWPCA report (Reference 1).
The data were plotted using various correlations; least square curves were
plotted using least squares fit equations generated by computer.
Obviously, not all of the correlations attempted were successful. Many
were discarded and equations were developed for only the best correlations
found relating the variables of interest.
Theoretical vs. Pilot Plant Data
The fuel needed to raise sludpe r-ombustion products to a selected tem-
perature can be determined from either theoretical calculations or pilot
plant data. Note that in the discussion below, # indicates pounds and refers
to the weight of solids plus water in the sludge cake (dry solids are referred
to as PDS).
The variables needed for fuel rate determinations are:
1) BAF = combustion air required @ h% excess 02, # air/# sludge
2) QF = required heat from fuel, Btu/# sludge
3) QLE = heat loss from pilot equipment which fuel must supply
(zero for theoretical calculations), Btu/# sludge
U) QPE = heat supply to the combustion air by air preheater in
pilot plant tests (zero for theoretical calculations),
Btu/# sludge.
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PAGE NOT
AVAILABLE
DIGITALLY
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Pilot plant data are more accurate than theoretical data for the above variables
for reasons explained in the next section.
The procedure for calculating BAF and QF follows. Given the elemental
composition of the sludge volatile solids the complete'combustion equation
for stoichiometric conditions is: (Note:(c) represents elemental carbon whereas
C represents the moles of 0p required for stoichiometric combustion of the
sludge volatile salads)
sludge volatile solids
A1(C) + B1(H2) + C(02) + D(N2)
Fuel
V
f
FM [
Sludge Air Fuel Air
) + 3-76F (N)
Combustion Products
'A3(C02) + B3 (H20) + [D + 3.76 (X + F) ] (HI,)' (D
where (X_+ F) = XF by the terminology chosen. In this discussion X is the,
moles of 0p required for stoichiometric combustion of the sludge and F is '
the moles of 0p required for stoichiometric combustion of the fuel. Note
that the sulphur content of the sludge has been neglected since its heat of
combustion is usually negligible.
From equation (l) the moles of C0p in the exhaust is given as
A3 = Al + FM (A2) (2)
and the moles of water in the exhaust due to the combustion of the H_
in the volatile solids arid fuel is
B3 = Bl + FM (B2) (3)
The value of X + F now redefined as XF is determined from equation
(1) as
XF = A 4 B /2.0 - C
8
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The pounds of volatile solids under consideration above is given by
P0VS = 12.0^) + 2.0(B ) + 32.0(C) + 28.0(D) (5)
and the volatile solids plus the inert solids gives the pounds of dry
solids under consideration as
PESC = P0VS/(PVS^LOO.O) (6)
Therefore the pounds of sludge (dry solids plus vater) under consideration
is
PS = 100.0 (PE6C/(100.0 - FH20) ) (7)
and the pounds of water under consideration is
PFH20 = PS - PD6C (8)
If the combustion products given "by equation (l) are added to the
water content of the sludge given by equation (8) the total moles of the
combustion products for the stoichiometric mixture for the volatile solids
under consideration is
PVT = A + B + D + 3-?6(XF) + PPH20/18.0 (9)
vhere PPH20/18.0 is the moles of water in the sludge. Note equation (9)
neglects the inert solids which remain in solid form and contribute little
to the total exhaust volume.
The operation of a fluidized bed incinerator is adjusted so that about
k% excess oxygen exists in the flue gas. To accomplish this concentration
of oxygen, the moles of excess oxygen (Y) which mast be added to the supply
air is derived as follows. Four percent excess oxygen is defined as
0.0^ = Y/(PVT + 4.y6(Y))
where lt.?6(Y) is the total moles of air for Y moles of oxygen. Solving this
equation for Y yields
Y = O.Ol* (PVT)/.8096 (10)
Then the total moles of the exhaust products at k percent excess oxygen is
= PVT + ^^(Y) (11)
The heat transported into the incinerator by the sludge is in two forms:
the heat contained in the mixture (using 0°F enthalpy base) and the higher
heat of combustion. The heat contained in the sludge entering the incinera-
tor is
SCP = PS (1.0 Btu/# °F) (60°F) (12)
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assuming the sludge specific heat as 1.0 and an inlet temperature of 60°F
the higher heating value of the sludge (OS) is given in Btu/# volatile
solids. Therefore the higher heating value of the sludge Btu/# sludge
containing a given percent of volatile solids (PVS) is
PSL = OS (PJ0VS)/FS (13)
The heat content of the air entering the incinerator is
AIRCP - I*.?6 (XF + Y) (M) (Cp) (T)
where M = molecular weight of air (28.9)
C = specific heat of air (0.2k Btu/#°F)
P
T = temperature of air assumed as 60°F.
Substituting the indicated values yields
AIRCP = 1980.0 (XF + Y) (1*0
Therefore the total heat supplied to the incinerator per pound of sludge
is given by
THCPT = QSL + QFU (FM) (12.0 Ac + 2.0 B0) + AIRCP + SCP/PS
2 d (15)
Next the total heat content needed to raise the exhaust products to
1^00°F will be derived. The temperature of ltoO°F was selected because the
minimum operating temperature for fluidized bed incinerators is around
1300°F and a slight safety factor is desirable to assure sufficient odor and
bacteria control. The heat content of the C0 , H^, BL, 0_ and inerts in the
lIj-00°F exhaust products from the volatile solids considered in equation (l)
and resultant sludge are respectively listed below in the general form.
CPC20 = (moles)(molecular weight)(specific heat at lUoO°F)(lUoO°F)
CPC20 = A (lA.O)(0.295)(ltoO.O) (16)
CPH20 = (B3 + PPH20/l8.0Xl8.oX0.555)(l^OO.O) (17)
CP2N = (3-76(XF + Y))(28.0X0.279X1^0.0) (18)
CP20 = Y (32.0X0.263X1^00.0) (19)
CPIW = (PDSC - POVS)(0.2U)(lUOO.O) (20)a-
If the sum of equations 16, 17, 18, 19 and 20 (SUMQ) is divided by PS, the
heat content of the exhaust products per pound of sludge (THCPT) is determined.
THCPT = SUM3/PS (21)
a. Specific heat is approximated by using data from Reference 46.
10
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The fuel rate and thus heat input to the incinerator adjusted by means
of the mole multiplier FM. When the thermal balance is reached between the
heat input to the incinerator and the heat content of the exhaust products
the variables BAF and QF can be evaluated from the equations developed above.
Thus since
BAF = (moles air required)(air molecular weight)/PS
BAF = k.rf (XF + Y)(28.9)/PS (22)
and
OF = (moles fuel)(fuel molecular weight)(fuel heating value)/PS
QF = FM [12.0 A2 + 2.0 Bg] QFU/PS (23)
Limitations of the Theoretical Determination of BAF and QF
An elemental analysis of sewage sludge volatile solids does not identify
the various compounds containing these elements. This analysis would be
extremely difficult to obtain. Therefore, when complete combustion equations
are applied to data derived from an elemental analysis only an approximation
of the air required for combustion is attainable. This is because the carbon
may exist as C, CO, CO^, CO and the combustion equations for these composi-
tions would each yield different air requirements. Thus it is anticipated
that the theoretical analysis set-up to determine BAF will yield a slightly
higher than actual value for most sludges.
In addition the heating value of a sludge could be calculated based on
the elemental analysis. However, the result would be in error for the same
reasons given above. Therefore, since an elemental analysis must be obtained
in the laboratory it is a simple matter to also perform a bomb calorimeter
test on the sludge to determine the actual higher heating value (QS). Because
of the availability of the data no attempt was made to calculate QS in the
computer program developed.
Air Freheater Sizing
The economics of operation will partially depend on the quantity of fuel
required to incinerate the sludge, an air preheater can be used to reduce
the quantity of fuel required. The equations developed below allow the
sizing of the air preheater so that a heat balance exists between the
exhaust products and incoming air. Three restrictions placed on design are
that the exhaust product temperature is 11<-00°F entering the air preheater
and no less than ^00°F leaving the preheater, and the air temperature leaving
the preheater is held to 1000°F or less. These restrictions are based on
the field data obtained and presented in Table I and II. A fourth restric-
tion is that the total heat transfered in the air preheater cannot exceed
that required from fuel and/or preheat in the pilot test or calculated
theoretical fuel.
11
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The derivation proceeds as follows. An air flow rate of BAF entering
the air preheater at 60°F has a heat content of
QAIR = BAF (0.21* Btu/#°F)(60°F) = 15-0 BAF (23-a)
At l400°F the exhaust products Have a heat content of
QE = QSL + QF + OPE + QAIR - OLE (2k)
based on the equations 1 through 23.
An air preheater can transfer a quantity of heat into the supply air
as long as this heat input does not exceed that determined from pilot tests
or calculations as
QFP = QF + QPE (25)
For a unit vith no air preheater the fuel cost is
CF = FC (QFP) (PCTY) (8750.0) (cAp)/io6 (26)
where 8750.0 is the number of hours in one year. If the exhaust products
are cooled from lUOO°F to 400°F in the preheater the heat transfered per
pound of sludge is
PC, - « (CAP) C,:,-) (27)
Thus PC is seen to represent the allowable heat which can be removed from the
flue gas without causing undue condensation of the water in the flue gas.
Condensation prevention is assured by holding the flue gas temperature
around tOO°F. The heat removed from the flue gas (PC ) is transfered to the
incoming combustion air.
To heat the incoming air from 60°F to 1000°F the air preheater would
have to transfer
PC2 = BAF (0.210 (1000.0 - 60.0) (28)
where 0.24 Btu/# °F is the specific heat of air assumed as constant over the
temperature range. The allowable air preheater heat transfer per pound of
sludge is the lower of PC , PCg and QFP thus
APHS = PC or PC2 or QFP (29)
whichever value is lowest. Note that this is the maximum heat transfer rate
(and thus fuel saving rate) possible for the particular system.
12
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Sizing the Reactor
The total heat release rate in the reactor is given by
SUMQ = (QSL + OFF) CAP + QL (30)
vhere QL Ls the heat loss rate from the reactor which must be generated by the
heat of combustion. Figure 3 shows the best correlation found relating the
grid area to the total heat release in the reactor namely
AG = SUMQ/155>000.0 (31)
This starting point was chosen because the heat release in an incinerator
is closely related to the volume of the combustion chamber.
This correlation was obtained by omitting ("discounting") the data for
the early units. Note that location 10 is shown as quoted insulation and
Hazelton insulation. The point labeled "quoted insulation" was based on the
grid sizing obtained from the firebrick thicknesses stated by plant personnel.
The point labeled "Hazelton Insulation" was based on the refractory thick-
ness known to be installed at Hazelton, Pa. Since the Hazelton unit was
roughly the same size as those at Kansas City it seems likely that the
refractory thickness would be very close for each of the units.
If the bed is considered as isothermal with combustion occurring near
the lower portion of the bed the ratio of AF/AG would be 1.0 as shown in
Figure 4 (assuming zero percent water content in the sludge). As water
content of the sludge increases the expansion ratio AF/AG must be increased
if gas velocity is to be maintained within tolerable limits at the top of
the bed. This is because the volume of combustion products per pound of
sludge increases when vaporization of the water and subsequent increases in
fuel and air requirements occur. For practical purposes the ratio AF/AG
cannot be allowed to increase beyond reason because of construction costs.
Therefore an upper limit of AF/AG = 3 was arbitrarily chosen for 100$
water conditions.
The combustion chamber for a fluidized bed is tapered so that the
upper cross-sectional area at the freeboard is larger than the cross-
sectional area at the grid. Such a taper prevents acceleration of combustion gases
and thus limits sand loss and over-fluidization at the top of the sand bed.
This taper was also found to be related to the water content of the sludge
as shown in Figure k.(3) Therefore the volume of the expanded bed (combustion
chamber) is related to the grid area, sludge water content and sand bed
depth. If the grid area is fixed then the sand bed depth is fixed for a
given sludge.
Thus for design purposes either the grid area or bed volume could be
selected first. The end result would be the same regardless of which
parameter was selected.
13
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H
-F
LTN
I
O
H
X
H
o>
co
-d
•H
o
CO
tj
H
O
13
O
-p
X 1967, 1968
1967 1966 1965
O Preheat
. .
| Quoted Insulation
First units built "discount" 1961 to 196^
io
:Hazelton
First preheat unit "discount"
Insulation
4~r4rH • •
i
155000 Btu/Hour/ft grid
10
50
Grid Area, Ft"
100
110
Figure 3 GRID SIZING
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H
en
CV1
2.6
2.5
2.1*
2.3
2.2
2.1
2.0
3 1-9
Q
3 1.8
a 1.7
S 1>6
a!
O
•£ 1.5
0)
- l.U
1.3
1.2
1.1
1.0
:
(VD
G
'
2
-
i /
Cn oP
.
c
'? - (
• r-T-
O(JY v TO t
• :
2 '
:
p
)
-------
From Figure k the freeboard area is found to "be
AF = AG/ 0.985 - 0.307 ((PH20/100.0)2 - 0-339 (FH20/100.0)^) (32)
where AF/AG = (HF/DCJ)2
Figure 5 shows the correlation developed for the expanded bed volume
which yields
VE = SUMQ/18,000.0 (33)
Since the bed volume is an inverted frustum of a cone having a volume VE
the height of the frustum is given from geometry as
HE
= VE/ 1.C&7 (AF/PI + (AF/PI)1'2 (AG/PI)1'2 + AG/Pl) (3*0
The diameter of the grid (DG) and diameter of the freeboard (DF) are
determined simply as
DG = (k (AG/PI))1/2 (35)
DF = (4 (AF/PI) J (36)
The standard practice appears to be to fluidize the sand bed until it
reaches a volume of approximately 1.5 times the volume of the static bed.
From this the static bed volume is determined as
VS = VE/1.5 (37)
Figure 6 shovs the correlation obtained for the height of the free-
board (HF)
HG = 1.6 (HE) (38)
Figure 7 is the best correlation found for determining the plenum
volume. It seems reasonable since the combustion air requirements are
somewhat related to the heat release in the reactor. The resultant
equation relating the plenum volume to the total reactor heat input is
PV = SUVR (2.5)/(lO)5 (39)
Thus the plenum height (HP) is
HP = PV/AG
The overall reactor height is obtained by adding equations 3^> 3
and 40 as
ORH = HE + HG + HP
16
-------
300
ITS
O
ft
'.I;
ta
d
o
CO
O
a
I
03
-p
o
•+• Expanded bed volume
O Static bed volume
o 50 100 150 200 250 300 350 Uoo 450 500 550 600 650 700 750 800 850 900 iooo 1050 iioo
•3.
Red Volume, Ft
Figure 5 SAND BED SIZING
-------
: 2 x Expanded bed depth
Assumed expanded volume
i = 1.5 static volume
1967, 1968:
*
1.6 x Expanded bed depth
1 x Expanded: bed depth
SSTSi
8 10 12
Expanded Bed Depth, Ft
Figure 6 FREEBOARD SIZING
18
-------
co
>— Plenum volume = 2.5 x Btu/Hour x 10~'
Total Btu/Hour (Volatile Solids, Preheat, Fuel) x 10
Figure 7 PLENUM SIZING
-------
Neglecting the plenum the outside surface area of the reactor where heat
is lost to the atmosphere is
A0 = PI (HG(DF) + HE(DF + DG)/2.o) (te)
o
Assuming a heat transfer convection coefficient of k.O Btu/hr-ft -°F,
the convection heat loss from the outside surface of the reactor is
QLL = k.O (A0) (TW - TA) (1*3)
If the wall temperature (TW) and ambient air temperature surrounding the
reactor (TA) are not given, values of
TW = 200.0°F
TA = 60.0°F
are adequate. Note that the radiation heat loss is negligible at wall tem-
peratures in the range of 200°F. A well insulated reactor should not have
wall temperatures in excess of 200°F because of the safety hazard of receiving
burns.
Figure 8 shows the correlation developed for determining the number of
sludge feed points installed in the bed section of the reactor. As the size
of the incinerator is increased it becomes necessary to feed the sludge into
the bed at several locations around the periphery of the bed to obtain full
use of the fluidized bed incineration capacity. Thus the number of feed
points required is given by
MFP = 100.0 (PDS)/2000.0(PCDS) (MO
where NFP is rounded off to the nearest integer.
System Power Requirements
The installed horsepower for the fluidized bed incinerator, based on
field data is presented in Figure 9 as
HPI = 15.2 - 0.0102^ (PVSH) + 0.0001607 (PVSH)2 (^5)
This includes the power requirements for all components from the centrifuges
through the ash system.
The fluidizing blower horsepower is included in the installed horsepower
above. However, it may be of interest and it is plotted in Figure 10. The
representative equation is
FBHP = -5-68 + 0.908'HPI - 0.000565 (HPI) (k6)
20
-------
£
I!
0 2000 ^000 6000 8000 10000
Pounds of Sludge Per Hour
Figure 8 NUMBER OF REACTOR FEED POINTS
-------
i Actual Measurement
„...,:-- ;j..;.i. :;.,;> -,.;-.::
•r":fi:
HP = 15-2 - 0.0102U# volatile solids/hour + 0.0001607 (#v.s.
200 250 300
Installed Horsepower
Figure 9 INSTALLED HORSEPOWER
koo
-------
ro
CO
a
ss
l
£
rH
cd
•P
e
o«
h
0)
pq
g>
-H
M
•H
T3
•H
X Fluidizing Blower H.P.
Total Blower H.P. = -5.68 -»• O.TOU H.P.
HOI
_®,x Data
A Fluidizing Blower H.P. = -5.68 + 0.908 H.P.T - 0.000565 (H.P. )
UO
20
150 200 250
Installed Horsepower
300
350 koo
Figure 10 BLOWER HORSEPOWER
-------
The operating horsepower for the system was found to be
OHP - 0.625 (HFI) (47)
"based on the data obtained for locations 1 and 2 in Table, I, II.
Sand Loss Rate
Sand losses occur because of non-uniform particle sizes cause by sieving
and attrition in the fluidized bed. The small particles are carried out
more easily than the larger particles. To fully fluidize the bed a gas
velocity is required vhich will fluidize the large particles. Since this is
too high a velocity to allow retention of the smaller particles the small
particles are gradually carried out the top of the bed. This sand loss rate
can be reduced to reasonable levels by providing a sufficient freeboard height.
A plot of field data gathered on the sand loss rate from the bed caused
by carryover in the exhaust gas is shown in Figure 11. The resultant equations
are
SLR = (10350.0 (DF/HF - 0.6)(PCTY) (8750.0)/30.0(8.0)) (ZIl) (48)
for
(DF/HF > o.64) and
SLR = (632.0 (DP) (PCTY)(8750.0)/30.0(8.0)(HF)) (ZIl) (49)
for
(DF/HF < o.64).
In the above equations where 8750.0 is the total hours in one year, 30.0 is
the average number of days per month and 8.0 is the number of hours per day
the field units are operated.
Carbon and Hydrogen Content of Fuels
Based on data obtained from major oil companies (Mobil, American and
Sinclair) the ratio of the moles of carbon to the moles of hydrogen in
number two fuel oil ranges from 0.54 to 0.80. For the purpose of this pro-
gram an average of the data collected (determined as 0.6o) was used for
the C/H ratio (i.e. 1.2 moles C for 1 mole Hg). For natural gas (CH^)
there is 1 mole of C for 2 moles of Hp.
System Costs
Cost Structure
The costs developed for this program include all components required
•24
-------
= 0.6 + 0.2/2070 (Sand Loss, #/month)
(DF/HF > 0.6U)
DF/HF = O.U75/300 (Sand Loss, #/month):
(#/month to
Expanded
Sand Depth
DF = Incinerator inside diameter in freeboard
HF = Expanded ( 50$) bed freeboard height
800 1000 1200 lUOO 1600 1800
Sand Loss Pounds Per Month (Carryover)
2000
Figure 11 SAND LOSS RATE
-------
for the fluidized "bed incineration system less the building and land re-
quirements. The components included in the cost data are:
l) Comminuter
2) Sludge Pump
3) Dewatering Devices (centrifuge)
*0 Waste Feed System
5) Reactor
6) Scrubber
7) Ash-Water Separation System
8) Air Preheater
The centrifuge is the only dewatering device included in the cost analysis.
In addition to the basic system cost an installation fee of 10 percent
must be addeda A Consulting Engineer's fee of 10 percent of the sum of
the System Cost plus installation fee must also be added.
System Cost Less Air Preheater
Figure 12 shows a plot of data -presented in Reference ^7. An overlay
on this curve is shown representing the field data collected. There appears
to be a significant discrepancy indicating that the manufacturers prices
quoted in Figure 12 are higher than the actual selling prices for this
equipment.
Table III shows the data from which the field data curve was plotted.
Since there was a significant difference in the cost data it was decided
to use both the manufacturers quoted prices and the field data prices in
the computer program for comparison purposes.
It was found that the field cost was correlated more closely by relating
the cost to the capacity in pounds of volatile solids per hour. This plot
is shown in Figure 13-
a. Data from a conversation with Mr. Stewart Peterson, W.E. Region Program
Director, F.W.P.C.A., Boston, Mass.
26
-------
w
TD
•H
H
o
w
fH
HI
ft
Td
EH
O
A - A = 22$ TOTAL SOLIDS
LOG COST = —
LOG CAP. - 1.64?
® - Units with air preheaters (not included in price)
4t - Units without air preheaters.
(28) - Numbers indicate percent of total solids in sludge.
11 - Other numbers indicate Installation location
(Key to table I ).
Points plotted using Engineering News-Record Dept. of Interior
Sewage Plant Cost Index for location of installation and
include all equipment costs less air preheater.
All prices include centrifuges.
Prices do not include building stack,
installation or consultant engineering fee.
B - B = Uof0 TOTAL SOLIDS
1
LOG COST =
2.18 LOG CAP. -
(Reference 1)
Jttti
T:
400 900 t 1 • 9001000 2000 JOOO 4000 5COO 4 7 • » 10000
CAPACITY (pounds of dry solids/hr)
Figure' 12 FLUID BED COMBUSTION SYSTEM COSTS IN FEBRUARY 1968 DOLLARS - [dollars/( 100 pounds of dry solids/hr)]
-------
TABLE III
DATA USED TO DETERMINE SYSTEM COSTS
Location
(Key to
Table I & II)
1
2
3
4
7
10
11
12
13
14
15
16
18
Systema
Costs
$
213,952
l4l, 500
220, 000
107, 446
150, ooo
673,810
191,000
171*-, 880
254,030
205,554
308, 600
222,100
172,600
Costb
Multiplier
1.01
1.16
1.10
1.14
1.00
1.05
1.05
1.08
1.01
1.01
1.01
1.01
1.04
Design
Capacity
#DS/HR
500
550
470
250
500
4910
282
490
875
500
1000
1210
450
$/100
#DS/HR
4.34
2.98
5-14
4.93
3-00
1.44
7.14
3-87
2.94
4.15
3-11
1.85
3-98
Includes correction for air preheaters.
air preneaters.
Costs are for systems witnout
b. Based on Engineering News Record, Dept. of Interior Sewage Treatment
Plant cost index from purchase date to February, 1968.
28
-------
ro
CD
ra
0) Oj
-P H
Cfl rH
0) O
•
CD
CO
\D
to
CO
0)
a
0)
-p
ra
300
200 - -
100
0 10 20 30 hO 50
70 80 90 100 110 120 130 ikO 150 160 170 180 190
Btu Per Hour Less Preheat Capacity x 10
Figure 13 SYSTEM COST LESS AIR PREHEATER FEBRUARY 1968 DOLLARS
-------
The equations resulting from Figure 12 for the manufacturers data are
C0RD = 1.0/(1.14(0.434294482) L0Ge (PDS) - ^'^ 100.0 (PDB) (50)
and
C0RD = 1.0/(2.18(0.434294482) L0G (PDS) - 4.38) 1OO.O (PDS) (5l)
for 22$ and 40$ respectively, total solids in the sludge.
The equation resulting from the field data plotted in Figure 13 is
C0R = 100,000.0 + 212.0 (PVSH) (52)
It is recommended that Equation 53 ^e used for costing the system less the
Air Preheater cost.
Air Preheater Cost
From the sizing requirement defined on page 12, an air preheater can
be costed using Figure 14. This figure shows a plot of air preheater cost
versus size based on field data. From the data available the cost was found
to be
APHC = 2-9 (APHS)/60.0 (53)
A linear relation was assumed because the heat transfer rate in an air
preheater is directly proportional to the heat transfer surface area. This
surface area is related to the amount of steel required to construct the
preheater and thus to the cost. The configuration of the air preheater used
in plants visited is shown in Figure 15- Alternate annular spaces carry
hot exhaust gases and in the other annular spaces the air moves in counter-
flow fashion.
Total Equipment Cost
The equipment cost is obtained by adding the reactor system costs (C0KD
or C0R) to the air preheater cost (APHC)
BCD = C0RD + APHC (54)
EC = C0R + APHC (55)
Installation Fee
Based on the information described the installation fee is
CID = BCD/10.0 (56)
CI = EC/10.0 (57)
depending on the data used for costing.
30
-------
CO
February, 1968 Dollars =
70/2k (Btu/Min.) = 2.9 (Btu/MLn.)
Numbers indicate installation location
(Key to Table I)
Figure lh AIR PREHEATER COST VS CAPACITY FEBRUARY 1968 DOLLARS
-------
Hot Flue Gas
to Stack
J
Preheated Air to
Incinerator
Alternate annular
spaces carry counter-
current flowing air
and hot flue gas
Figure 15 ANNULAR COUNTERFLOW CONCAR-TYPE AIR PREHEATER
-------
Consulting Engineers' Fee
Based on the information described on page 26, the consulting engineers'
fee is
CEFD = (BCD + CID)/10.0 (58)
CEF = (EC + Cl)/10.0 (59)
depending on the data used for costing.
Total System Cost
The total system installed cost (TSCD or TSC) is the sum of the equip-
ment cost, consultants' fee and installation fee
TSCD = BCD + CEFD + CID (60)
TSC = EC + CEF + CI (61)
Air Preheater Fuel Savings
The cost of fuel used to operate an incinerator can be reduced by the
use of an air preheater. The quantity of fuel saved is directly proportional
to the air preheater size thus
CFP = APHS (FC) (PCTY) (8750.0)/106 (62)
represents the annual cost of fuel saved by the preheater where 8750-0 is
the total hours in one year.
In the above analysis of the air preheater the maximum preheater size
allowable for the system has been determined. On this basis some systems
will allow the air preheater to be so large that it will cost more than the
reactor and other components combined. The economics of capital cost vs.
operating cost cannot be dealt with directly here because the program is not
set up to evaluate this. This is so because FWPCA has planned to use this
program as a subroutine. The main program is equipped to evaluate the economics
required above. The exact routine to be used for evaluation of the economics
will depend on the shape of the fuel cost curve (considering variable fuel
cost vs. monthly usage and location). A "Do loop" which increments fuel cost
along the fuel cost vs. usage curve and compares this cost to preheater cost
may be the best method of cost optimization.
Annual Operating Cost
The fuel required to operate the system must supply the heat required to
burn the sludge minus the heat supplied by the air preheater. Thus the cost
33
-------
of fuel to operate the system for one year is
CF0 = (QFP (CAP) - APHS + QLL(ZIl)) PCTY (8750.0) FC/106 (63)
where 8750.0 is the total hours in one year.
Since the operating horsepower has been determined on page 25 the
yearly cost of electrical power is
CP = 0HP (EPC) (0.7^6) (PCTY) (8750.0) (6k)
where 0.7^6 is the conversion factor from horsepower to kilowatts.
Reference 1 indicates that operating labor is required for I/1* of time
that the fluidized bed incinerator operates. This agrees well with informa-
tion obtained in the field. Therefore, the annual cost of operating labor
for the combustion system is
CL = 0.25 (CLR) (PCTY) (ZIl) (65)
The reason for sometimes using more than one incinerator is described on page
^5. Also note that Equation 65 is directly related to the system PVSH
because ZII is related to PVSH (see page ^5)- Although a man is not re-
quired full time to operate the incineration system someone must be in the
general area in case of emergencies. Therefore the reported labor costs
vary in different installations depending upon the work load which must be
handled by the plant operators. In most cases the incinerator operators
can be used for other plant operations after an initial startup period.
The annual operating cost is obtained by summing Equations 63, 6^ and
65
C0 = CF0 + CP + CL (66)
Note that this cost does not include the cost of flocculent added at
the centrifuge inlet to aid coagulation. The more commonly used flocculents
and dosages are listed in Table II of the field data summary.
Annual Maintenance Cost
The annual maintenance cost includes plant maintenance labor, service
and repair labor, component replacement cost and sand replacement cost.
Plant maintenance labor cost is accrued because of repair work and jobs
such as lubrication and sand replenishing required during the year. There
was no field data available on these costs, however, the maintenance costs
were stated to be quite low at all installations. It is safe to assume a
maintenance cost of one man hour per day. This yields
CIM = (CLMR (PCTY) (8750.0)78.0) (zii) (67)
where 8.0 reduces the cost to one eighth of a man hour for every hour of
Operation.
-------
Data were not available for the cost of labor to repair instrumentation
and other equipment requiring outside of plant service labor. Therefore,
it was assumed that one man hour of service labor was required for each
150 hours of operation. The service labor cost is given by
CLMA = (CLMS (PCTY) (8750.0)/150.0) (ZIl) (68)
The cost of equipment replacement was found to be very low. Most failures
were in thermocouples and fuel nozzles. There was not data on these cost.
Thus the expression which was assumed is
CEE = 365.0 (69)
where CER = yearly cost of equipment replacement. This is equivalent to
$1.00 per day of operation.
The rate of sand loss per year was defined on page 2U . Sand costs about
$20 per ton. Therefore, the cost of sand loss per year is
CSL = SLR (20.0)/2000.0 (?0)
Then the annual maintenance cost is easily found as
CM = CLM + CLMA + CER (ZIl) + CSL (?l)
Annual Operating and Maintenance Cost
The total annual labor and maintenance cost is
TCMO = CM + CO (72)
Note that this cost does not include the chemical additives used to aid in
dewatering the sludge.
Scrubber Costs
Table IV shows representative scrubber costs for scrubbers made by the
Sly Manufacturing Company. These scrubbers were installed on some of the
installations visited during this program. Scrubber costs were included in
the computer program .lump sum costs, but are presented here to allow reference
at a future date should detailed cost data be available on other system
components.
Scrubbers installed on installations visited allowed particulate emissions
in the flue gases of from 0.05 to 0.75 grains per standard cubic foot of
flue gas. The tolerable emission level is determined by the local air pollu-
tion laws.
35
-------
TABLE IV
SLY SCRUBBER COSTS*
Inleta
Gas Volume
CFM
500-1,000
3,000
5,000
7,000
9,000
12,000
Inlet*
Gas Volume
CFM
500-1,000
3,000
5,000
7,000
9,000
12,000
Two Stage Impinjet
3 GPM Water/1000 CFM (inlet) *P = 4.
Outletb Outside
Gas Volume Diameter
CFM Inches
It76
2,856
4,760
6,664
8,568
11,424
24.5 GPM
20
30
40
^5
50
60
Three Stage
•5" H20
Material and
316 ss
(3/16")
$ 2636
4146
5897
6825
7969
10450
Impinjet
Water/1000 CFM (inlet) ^P
Outlet0 Outside
Gas Volume Diameter
CFM Inches
327-654
1,962
3,270
4,578
5,886
7,848
20
30
35
40
45
50
316 ss
(1/8")
$ 2162
3339
4708
5460
6349
8315
= 9" H20
Material and
316 ss
(3/16")
$ 3223
5157
6311
7396
8725
9538
316 ss
(1/8")
$ 2627
4144
5018
5799
6911
7554
Thickness
316 ELCSS
(3/16")
$ 2861
4479
6429
7410
8679
11318
Thickness
316 ELCSS
(3/16")
$ 3497
5558
6826
8003
9313
10400
316
ELCSS
(1/8")
$2436
3597
5086
5899
6882
897^
316
ELCSS
(1/8")
$ 2833
4445
5307
6386
7449
8198
* Courtesy of Mr. Harding of Sly Manufacturing Company, Cleveland, Ohio.
Costs do not include pump or surge tank.
a. Saturated @l60°F.
b. Saturated @156°F.
Q. Saturated @ 100°F.
36
-------
Cost of Installation^
A plot of the cost for fluidized bed incineration equipment (less
a-ir preheater, for primary sludge is shown in Figure 16. The assumptions
Tiade in plotting Figure l6 are that each person produces 0.2 pounds of
dry solids per day. If ve assume primary treatment removal of suspended
solids is 60$ thus 0.12 pounds of dry solids per day per person must be
incinerated. Each person creates 100 gal/day of sewage water. Therefore
1 mgd is equivalent to sewage waste from 10,000 persons (1200 pounds of
dry solids/day) and 100 mgd is equivalent to wastes from 1,000,000 persons.
Figure l6 shows the installed cost (less air preheater) of the
fluidized bed incineration system (based on the field data curve of
Figure 13) as a function of the primary treatment plant size in mgd.
The assumption of an 8 hour per day burning period has been made (i,e. 1200
pounds of dry solids/day -f 8 = 150 pounds of dry solids/hour). A sludge
having 9000 Btu/#/s and 1% HO has been assumed.
37
-------
CO
CO
o
Fn
-P
w
O
0
Cost of Fluidized Bed Incineration Systems
calculated assuming no Air Preheater is used.
rtr rttr-tr-trrr- >:•!'.::.:. ^.:.t:.:: .!.::. rt- .'I I.;!..1;. .-;.'.. - r-rr-rrrtm
iSBg ::: Bpjtffin laa?J :::"- u :.'••• - P [23 ::::-"' •:•.•::-iftrj
r rli±±- — t!!!^!^^.-^---^!!^*!^:! ,,-1},-,, ;.f: - • : t: : ;(^-Utl-H
Largest plant (10,000 PDS/HR) which cost data was
available for (see Figure 12).
m+
Assumed 8 hr burning duration/day
Primary treatment sludge
9000 Btu/lb volatile solids
PVS = 75
PH20 = 70
Number 2 fuel oil
Less air preheater
Extrapolated Curve
10
20
30 Uo 50 60 70
MLllions of Gallons Per Day
100
Figure 16 PLANT SIZE IN MILLION GALLONS PER DAY VS. COST
-------
COMPUTER PROGRAM
Listing of Program
The complete program developed is listed in Fortran IV pn the following
pages.
-------
FLUIDIZED BED INCINERATION OF SEWAGE SLUDGE FBINC 1
4
DIMENSION A(3).B(3) fPCOl
FBINC
10.2./i' C3AIR.' .F10.2./.1 CAP' ' tF10.2 i/t ' PDS-1 tFlO.2 t / i ' PM20»' .F1FBINC
30.2,/,' OFU°< tF10.2)
FBINC
" •' II FORHATT IHO.'AF*1 iHU.Z./, • Dh" • >hlU.2i / t* A(i»' .h lU.Zi/ I ' Ub= ' .hlU.hUINV.
, 12./.< VE-'.FIO.Z./.' HE-'.F10.2./.' ORH»' iF10.2./ . ' OHF>- ' .F10.2./ .FBINC
f ,_,J— „
CO
40 n
{• «hK='.HU. «!•/«• HHIB- if-lU.il/. • hBMK"' .h JU.Z./i • Ml-"
12 FORMATdHO.'FCo' .F10.2./,1 CLR= ' .F10.2 ./ . ' CLMR*'.F10.
20<2i/f' CP°' >F15i2./i' CFO"1 •F15»2t/.1 APMC= ' iF10«2« / .
—72"f/ilfi CEF« ' tF10.2.^ > ' CEFP=* >F10«2» ft ' EC" ' IFI0.2 ./« •
13 FORMATIlHO.'TA»ltF10.2./«l TW= ' tF10.2«/i ' PAPH='.F10.2
• < r i u • <; i )- u i ii<.
2./.1 CLMS='FBINC
1 EPC"1 .FiO. FBINC
1='. F10. 2. /.FBINC
i/i1 SLRi'iFFBINC
10 FORMAT (1H0.1 ASSUMED PROGRAMMED SLUDGE ELEMENTAL COMPOSITION') FBINC
16 FORMAT (1H0.1 NATURAL CAS FUEL1)
18 FORMAT <1HO.' WATER QUENCH MAY BE REQD. IN REACTOR* 1
20 FORMAT (IHO.'CALC OFiBAF iQPE'O .OLE-0 ' )
FBINC
••• mini.
FBINC
FBINC
— 71 FORHATtrHlV'TTAbt'iiUI mjNL
22 FORMAT (1HO. 'SYSTEM IS TOO SMALL TO BE COSTED BY DORR CURVES >,/•' FBINC
TAW-ESTTmTf-TVG'IVE'N' BTTTELD UATA lUOAT'lUNS*./ r'-'SMf
2 FOR CORD. CEFDiECO. CIO. TSCD. SHOULD BE DISREGARDED')
Z«, FORMAT! 13F6. 2)
26 FORMATC3I11
100 READI2.23 I OS.OFU .CAP.TA.TW.CLR
READI2.26 ILITEiLITiLll
WR1TEI3.21 ) M
110 READ12.23 I OF .OPE .OLE .BAF
GO TO 270
1-0
QPE-0.0
GO TO ( 130* 140ULIT
3(11* *Q3*7
D-. 001107
GO TO 150'
WRITEO.15 I
W™ •* * * * • -
i * i!"" . " -
DBTH ' KK 1 n 1 C'DKBTnVT
FBINC
FBINC
TUMI;
FBINC
" PblNL
FBINC
FBINC
F8INC
FBINC
FBINC
FBINC
FBINC
FBINC
u " PC rwe
FBINC
FBINC
FBINC
FBINC
FBINC
•
•3
*•
5
1
a
9
1U -
11
13
1*
15
17
10
19
21
23
25
27
•fa -•- _. . - - ... --
29
31
33 '
35
37
39
41
t!
45
47
49
»
11
59
57
59
i * •*
^
M
«
M
.
r •
.
-------
0«0/28*
FBINC 61
1
1
1
, 1
(
t
-.
\
11
1
r
n
160 A(2)«lt
WR!TEOtl6 )
170 A(2)"1.2
WRITcOil? )
PDSC-POVS/IPVS/IOO. >
PPH20-PS-PDSC
OSL-OS*POVS/PS
B(3I-B(1)+FM»B(2)
IF(XF) 200, 210,210
210 PVT"A(3)-»-8(3)+D-t-3.76»XF+PPM20/18.
V~ «0'iMPVT / • B096
PV4T«PVT+4.76*Y
CPH20=(B(3>+PPH20/18i)«14000.
CP20-Y»11800.
SUMO-CPC20+CPH20+CP2N+CP20+CPIN
AIRCP=IXF+Y)»19BO.
SUM-THCP-THCPT
IFCI-1) 230,230*220
230 IF(SUM) 240,260.250
60 TO 260
GO TO 190
BAF"137.5»UF+Y)/PS
QAIR«15.»BAF
QFP-QF+OPE
280 CF»FC»OFP«PCTY»I8750.)*CAP/10.«»6
PC(2)-BAF*(24*(1000.-60
300 PCI3I-PCI2)
?10 DO~OFP~PC(3)
IFIQFP-PCI3) 1 320,330,330
GO TO 340
•
mini ot ~~
FBINC 63
FBINC 65
BIHC 4fi
FBINC 67
FBINC 60 J
FBINC 69
TIC TO
FBINC 71
FBINC 73
FBINC 75
FBINC 77
FBINC 79
FB INC BO
FBINC 81
FBINC 83
FBINC 83
FBINC as
pat Mr QfL
FBINC 87
FBINC 08
FBINC 89
FRINT 90
FBINC 91
FBINC 93
FBIMC Uh
FBINC 95
FBINC 97
FBINC 99
FBINC101
FBINC103
FBINC105
FBINC107
FBINC109
FBINClll
FBINC113
FBINC115
FBINCllt - - , - - t ,, r - T nnrr
FBINC117
v FBlNCllfl
FB1NC119
1
' "J s
"'
•a
v.
"U
u,
t
•a
H
.'
M
-------
»t
1—
4
340 APHC-M2.9*APH5/6CN)
350 APHC-0.
IF(CFP) 370,370.390
GO TO 390
9 BO PC 1 3 I BU iO '
CFP«Oi
390 PCDS-UOO.-PH20)
PVSM-PDS*PVS/100.
if IPVSM— j5uo«l taumauitOu
400 ZII-2.
410 ZJ"PVSH/2li
1FIZI-1500.I 440.440.420
GO TO 410
taflr ZT'fvsrt
Z1I-1.
PDSJ»POS»ZI/PVSH
AG-SUMQ/155000.
VE-SUMO/18000.
DG»SQRT(4.0*AG/PI>
VS-VE/1.5
PV"SUMQ»2.5/10.t«5
AO"PI«(HF»OF+HE*(DF+DGI/2.0)
IF(QLL-OL) 470. 470.460
1 480 OL"GL*Z99ffU— • — ••• — • ' • •
GO TO 450
NFP»FLOATUFIX(100.0»POS!/<2000.»PCDS1+0.5000Q1> 1
480 NFP»1.0
IFIPCDS-31.) 500.500.510
GO TO 520
520 COR«100000.+212.«PVSH
FBKP1«-5.68*.90»HPI I-.000565«( (HPI I l»*2>
CHPTT,TSZS»HPTI
HPI-MP|I*ZII
OHP«OHPI»ZII
ECD-CORD+APHC
CJD-ECD/10. __
FBINC121
FBINC123 - '
FBINC125
FBINC127
• FBINC12V
FBINC131
FBINC133
FB1NC135
FBINC137
FBINC139
FBINC141
FBINC149
FS1NC145
FBINC147
FBINC149
FBINCL51
FBINC153
FBINC155
FBINC157
FBINC159
FB1KC161
FBINC163
FBINC166
FBI NCI 67
FB'IMC169
-, ... i FU'iNL 1 T 0 ' |IT"
FBINC171
FB1NC173
F6UC175
FBINC177
FB1MC17^"^^— -~-_ x
- ^
t
•
,.
„
"li
1
-------
CEFD-1ECD+CID1/10.
FBINCI81
•
•fl >B
)f'»—
CL-0.25*CLR»PCTY»ZII
CFO-(OFP«CAP-APHS+OLL»ZIII*PCTY*8750.»FCi'10.«6
530 CFO-0.
IF( (DF/HFI-.64) S50t550i560
GO TO 570
570 CLM-CLMR«PCTY»1093.7»ZII
C5L-SLR/100.
TCMO-CM+CO
TSCO-ECO+CEFO-KIO
FBINC183
**
FBINC1B5 \
FBINC187
I
FBINC1B9
FB1NC191
FBINC193 , ,
FBINC196 !
FBINC197
FBINCI99 ' ,
— — — - CAPt'C'APv'ft 1 ————— — .-- — .. .... •-•T-UITH.«VU , »
WRITE (3ilO I OS.QF»QPE1»QLEtQAIRiCAP.PDS.PH20.PVS.BAF.PVSHiPCOS.QFFBINC20l ,
WRITEOtll I AF»DF.AGtDG.VE.HE,ORHiOHP.NFP.HPI.FBHP»HF
580 WRITE(3>22 ' )
590 MR1TCO»18 1 f C iCtBrCfcMRir€teM&tCLMAtCSt;T€OT€f<»€PTCFO»APHCltifi^
ICEFDtEC.ECD.CFP.COR.COROtCI.CID.TSC.TSCD
WRITEI3>23)PV4T
CALL DATSW(4iMOREt
600 CALL EXI-T
CNP —————.——————— — — — — - — — —
-
t
.-' • -'
••""'--
. : .--ci -•-•»::... ,
. r 1 ' I ""
'.N-i-M
-t... -«.aj'.-.-
•
1
-
roinkcuc
FBINC203
FBINC205
FBINC2Q7
FBINC209
FBINC211 !
FB1NC213 ;
214 ;
"
•
".'
':
1 c ; .
-.- •. •
'
n ' «•"-«« — -
'
-------
Flow Chart
The flow chart for the computer program developed is shown in Figure 17-
Figure 1? FK)W CHART OF COMPUTER PROGRAM
-------
How to Use The Computer Program
Options in the Selection of Input Data
The program is set up to follow different loops depending on the index
values read in. The options available are:
l) The use of pilot plant data for fuel and air requirements or
the use of the calculation routine for these variables set up
in the program.
2) The use of the programmed sludge chemical composition or an
input sludge chemical composition for calculation of the
variables in 1 above.
3) The use of natural gas or Number 2 fuel oil in the calculation
of 1 above.
In the use of option 2 above the operator should note that the programmed
sludge composition is a representative value based on Reference 2. The errors
involved in using this routine instead of pilot data are that the assumption
must be made that the sludge exists in an unoxidized state. Therefore, the
oxidation reactions would be
However, the sludge consists of compounds in a partially oxidized state, for
example the combustion reactions
C0 + 4-
may occur instead of the complete combustion reactions shown above. Thus
the difficulty and inaccuracy of determining the fuel and air requirements
needed to support sludge combustion is apparent. Because of this limitation
it is advisable to use pilot plant data when accurate results are required.
No assumptions can be made as to the accuracy of calculations when the
programmed sludge elemental composition is assumed. The insertion of a true
elemental composition for the sludge of interest, with a corresponding sludge
heating value (OS) may yield a more accurate analysis.
-------
Reactor Sizing Limit
As with any mechanical equipment, there is a maximum tolerable size above
which a fluidized bed incinerator cannot be economically constructed. The
physical size and operating stress combine to make this limit apparently a
unit with a design capacity of 1500 pounds of volatile solids per hour or
a reactor freeboard diameter of 16 to 17 fept (based on Kansas City units).
Therefore, when a system with a higher capacity than 1500# VS/HR and/or a
greater freeboard diameter than 16 feet is required, the system should be
split into two or more systems of equal size (i.e., PVS/2, FVS/3, etc.) if
it is to be handled by this program. This is done in the computer program
and ZII is used to represent the number of incineration reactors having a
volatile solids capacity of 1500#/hr or less. The computed capacity of each
reactor is ZI. The system cost curves are defined to 10,000# dry solids/hr
(Figure 12). Accuracy beyond this capacity is uncertain and the computer
program usage should be limited to capacities below the above.
Air Preheater Option
The decision to use an air preheater can only be made through an
economic analysis which FWPCA has set up in the executive program. Since
this program will be used as a subroutine for this executive program, no
attempt was made to optimize the system. The air preheater is sized based
on the required system heat requirement from fuel and the preheater. The
maximum preheater capacity for each reactor vessel is given by
APHSI = APHS/ZII (73)
To optimize the air preheater size, a trade-off between fuel costs and air
preheater size must be accomplished in the executive program.
Data Input and Output
Figures 18, 19 and 20 show the input cards used to obtain the data for
Figure 16. The output data from the computer program for each set of data
input are shown respectively in Figures 21 through 32.
To obtain this data, two cards
APHC = 0.0
APHS = 0.0
were inserted after card FBIMC121 in the program listing shown in this report.
This was done simply to eliminate the air preheater, since the cost optimiza-
tion needed from the executive program to aid in sizing the preheater, is
not included in this subroutine.
The indices used for program control on Card 3 are described below:
1) LITE = 1 when pilot plant data are used for QF, QPE, OLE, BAF,
LITE = 2 when QF, BAF are unknown.
2) LIT = 1 when sludge elemental composition is known from tests,
LIT = 2 when sludge elemental composition is unknown.
3) KEI = 1 when using natural gas fuel,
LII = 2 when using #2 fuel oil.
-------
CARD #1
CARD #2
CARD #3
QS, QFU, CAP, TA, TW, CLR
FC, PCTY, PVS, EPC, CLMR, CLM3, PB20
LITE, LIT, LII
9000
r-,-%
1 .3
C_ An
ecMrar
CTATCIAIT
CfOO
COWUT
STATEMENT
NUMBER
010 0 0 0
ri i « s
if't 1 1
Fill1 2 2
33333
44444
55555
66666
77777
88888
99999
.10000. 500. 60. SCO. 5000.
3| .24 70. .03 3. 8. 70.
— L : : ; i
s
£
S FORTRAN STATEMENT
<
IOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOCOOOOOOOOOOOOOOOOOQ
1 7 1 9 1011 UtJHlSlilT l8ISai1En2)BJ8z;n2SX31BU»35»373l33«tM!O»-, 45«47U45aiSiaaS4aaSI5l59S06l6JO«OS6S!OG9JOII7!
11 1111 til 1 It 1 11 111 11 1 11 11 1 1 1 11 1 11 11 1 1 111 1 1 1 111 1 111 11 1 111 11 M 1)1 Ml
!222222222 22 2 22 22222 22 222 2 2 222 222222222222 22222 222 22 22222222 2222222
1333333333333333333333333333333333333333333333333333333333333333333
1444444444444444444444444444444444444444444444444444444444444444444
1555555555555555555555555555555555555555555555555555555555555555555
.666666666 6.6 666666666666666666666666666666666666666666666666 6 G 66666
7 7 7 7 7 > 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7
888888888888888888888888888888888888888888888888888888888888888888
1999999999999999999999999999999999999999999999999999999999999999999
7 1 1 Hll I!131415I8H IIIS»!ina2«25a2iaaB!IB33»6»J7»lS<»4IC4J«45«47«Oa5l5JaM!BS85;aS96»SiaeiE46St56jaE9m7l7?
IDENTIFICATION
00000000
n74isii77itnn
11111111
22222222
33333333
44444444
55555555
66666666
77777777
88885888
99999999
11 74 75 76 17 71 79 n
ISC 686157
Data Cards Case 1
9000
C IWI
COOCHT
1.3
Cm
"COMMENT
212
C_ «"
COMICMT
STATEMENT
NUMBER
OjOOOO
lf.111
L|2l22
33333
44444
55555
666G6
7|7 7 7 7
88888
9l9 9 9 9
1 1 12 ] « 9
.
s
3
i
«
s
i
0
1
2
3
4
5
6
7
8
9
c
10000. 5000. 60. 200. 5000.
.24 70. .03 3. 8. 70.
; 1 is ' ' B
FORTRAN STATEMENT
000000000000600000000000000000000000000000000002000000000000000000
T 1 1 18 till 13 14 15 U 17 11 19 70 21 U 23 N IS ZB 27 21 29 30 31 12 33 M 15 36 31 31 39 40 41 42 4] 4*i 45 46 47 49 49 SO 51 52 S3 54 55 SS 57 SI 59 GO 61 C2 S3 64 S3 U W 61 69 70 11 71
Ml 11 1 1111 1 1 1 11 II 1 i 1 1 1 1 111 1 1 til 1 1 11 1 11 1 1 11 1 111 1 1 11 1 11 11111 M 1 1 1 11 1
222222222222222222222222222222222222222222222222222222222222222222
333333333333333333333333333333333333333333333333333333333333333333
444444444444444444444444444444444444444444444444444444444444444444
555555555555555555555555S5555555555 55 555 55555555555555555555555555
B66666666666666EG6666G666666666666666666666666666666666666666666G6
7 7 7 7 7 > 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7 7
888888888888888888888888888888-888888888888888888888888888888888888
999999999999999999999999999999999999999999999999999999999999999999
7 1 1 Ull 12 11 14 IS 11 17 11 ISM II 21 13 « 2S 21 27 II 29 3D 31 » 33 MB* 37 » » M 41 4! 4] 44 4141 4f 41 4)951 B SIM 55 !> S7 a 59 GO 616261 14 DO (7 M U 70 71 72
IDENTIFICATION
00000000
73 74 n n n 7i n to
11111111
22222222
33333333
44444444
55555555
66666666
77777777
88888883
99999999
73 74 75 7t 77 II 19 10
ISC BBaiST
Data Cards Case 2
Figure l8 DATA CARDS
-------
9000
Ck. rap
CHUT
1.3
c-.i.
212
Q_ ™>
-«Bft
STATEMENT
HUUBEB
00000
IjllH
A2,22
33333
44444
S55S5
66666
1
77777
88888
09999
i 1? i i i
10000.12500. 60. 200. 5000.
!
| .24 70. .03 3. 8. 70.
:
FORTRAN STATEMENT
lOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOSOOOOOOOOOOOOOOOQOO
11 11 11 1111 1 111 1 1 1 1 Mill 11 11111 11 111 1 11 111 1111 II 11 111111 1 t 111111 111
1222222222222222222222222222222222222222222222222222222222222222222
1333333333333333333333333333333333333333333333333333333333333333333
14444444444444444444444444444444444444444444444(4444444444444444444
1555555555555555555555555555555555555555555555555555555555555555555
>666G66E66GG6GG6666666E6G6666666666G 666 66666666 S6B6GG666666666G 6 B66
77777/77777777777777777777777777777T777777777777777777777777777777
888838888888888888888888888888888*88888888888888888888888888888888
999999999999999999999999999999999999999999999999999999999999999999
IDENTIFICATION
00010000
nnnnnnnn
11111111
22222222
33333333
44444444
55555555
66 6 6 66 6 B
77777777
98888888
99999999
u 14 TJ TC n n n n
isc eaaisv
Data Cards Case 3
9000
L/*"cw«ttPn
1.3
C»- "*
coHHcm
212
^ re.
^ MMCNI
STATEMENT
NUMBER
00000
IfllM
!i|2*22
33333
44444
955S5
66SB6
77777
88888
9|9 9 9 9
ill 1 « 9
i
3
s
2
i
i
0
i
2
3
4
S
6
7
8
9
c
10000.25000. 60. 200. 5000.
.34 70. .03 3. 8. 70.
n n
FORTRAN STATEMENT
000000000 000 00000000 UOO 00000000000000000 0000 000 COO 00 000000 00 0000 00
7 1 1 Nil l?UMIi16IIUUIDII2Zn!4ZSS779nBll329MEV3)3894414241ilG4i>Oia7l79«
1 1 Ml 11 1
22222222
33333333
44444444
5SSS5SS5
66666666
77777777
88B88B88
99999999
7J 74 71 75 77 n 78 •
Data Cards Case
Figure 19 DATA CARDS
-------
9000
^ ran
^ COHHEMT
1.3
f* fOR
^/ COKM-NT
SIS
^ FOR
Lj COHCHl
STATEMENT
NUMBER
OjOOOO
1,111
69 70 71 72
11111 1 1111 11 1 11 1 1H1 1 1 1 111 1 1 11 11 1 11 11 1 1 1 1 1 1 1 1 1 1 111 1 1 1 11 1 1 1 1111 1 11 1
!222222222222222222222222222222222222222222222222222222222222222222
1333333333333333333333333333333333333333333333333333333333333333333
1444444444444444444444444444444444444444444444444444444444444444444
1555555555555555555555555555555555555555555555555555555555555555555
!66666666666666 66666666666 6666666666666 666 666666666666666666666666 6
1777777777777777777777777777777777777777777777777777777777777777777
)88888888888888 888 88888888 Bfl 888 88888 888888 88 B88 8888 8888888 888 88 888 B
9999999999999999999999999999999999999999999999999999999999999999999
! 7 1 9 1111 1! 13 14 IS 1617 II 19 20 21 25 21 24 2! 26 27 213 » 11 32 33 14 15 3837 » 39 «41 42434(45 « 47 41 4) S3 51 52 53 54 55 5*5751 59 60 816261 6165 6667 U 69 70 71 72
IDENTIFICATION
00000000
13 71 19 71 17 71 19 B
11111111
22222222
33333333
44444444
55555555
66666666
77777777
88888888
99999999
73 74 75 78 77 ffl 79 «0
ISC BBBIB7
Data Cards Case 6
Figure 20 DATA CARDS
-------
.. -„- ... -_..
wr tofir tu*-c=utwLC"v
WAICK UUtNtn MAT DC KtUtf* 114 KCAblUK
QF«
OLE"
0*00
OtOO
WkIR«
CAP»
33.76
500*00
„ PH20«
,. BAF-
KVSM»
1 PCDS»
70.00
2^25
1U5.UU
30.00
DF"
HE-
7V9V
3.16
2*94
"9"8v85 "" "
7.97
ll__
\
If—
^B...
OHP
9.93
NPK
HP1
HF"
l.OU
15.89
-8V«T
12.75
.^SI---.I.?-I0?-S^*L._..T° Bf .C°JT5?-?Y^PP^-.^U.-VES
AN tSIIMATfe 15 GIVEN BY PItLD DATA EQUATIONS
ANY DATA PRINTED FOR CORDtCEFD.ECD.CIDiTSCD. SHOULD BE DISREGARDED
FC
1.33
CLMR
3.00
1
•*
CLMA
BrOO
111.99
CO
1086.39
CP"
466.94
CFO"
. APHC- 0.00
CEF" 13448.60
~CBPD5—2557IV5T
EC" 122260.01;
ECD
CFP
Z320l4«3T
0.00
-------
—
12226*00
CIO"23201.43
TSO 147934.62
TW- 200.00
SLR- 1379.19
0.
V..
II
Figure 22 SAMPLE MTA
50
-------
TE
uw « u/. u
OS*
OF- 0.00
•)'— "QPE-- ........ 0.00
OLE; _ o.oo
wA!R» 33.76
^ CAP- 5000.00
""-— T»OS«— ~i50o-icro
PH20« 70.00
ji —
- ._
PV5H» 1050.00
1 PCDS" 30.00
"-—- oTOir— TOT
}"--- -AF« .......
OF" _ 9«67
3S5» 63.21
DQ" 8.97
"""VE^ ...... 5**Y3]f
HE- 7.97
"'""""OffH-" ....... 24.60
OHP" 113.51
NFP» 3TS5
1 HP I" 181.61
..... FBMF; ...... i39VlV
, HF- 12.75
^n
"1 FC- 1.33
x tLR" sugo.gu
1 CLMR- 3.00
— "CLflSV ........ 1SV80'
CLMA= 111.99
^-—-c^L«- ..... T«*;*9
CO" _ 6606.37
CM3 ifur.vs
, CP" 5334.84
-TCPO^ ------------ -yTT;
APHC« 0.00
"— -Epca --------- CTV07
CEF» 35486.00
ttru= 9^roH*Hd
1 EC" 322600.06
""ECBS'"4T9¥BO-;*T
CFP» 0.00
-,"— "CORS-WZBOWCnS
, ^ CORP- 479680.81
tlB , 32ZOO.UU
, CIO" 47966.07
DATA
51
-------
•x1 — -T SC&«"W41-3Y7$--
I«» OUtUU
\ ™" 200.00
" "PAPH-"45"6V6b"
, SUR» 14349.66
if..
a—
n_
0»
a.
>„ Figure. eh__BUmBJDKI!A_
52
-------
'3
I.AH. «r IBAP »WKtsUtULfcHU
' UATEfc mJENCn HAV BE—(TEOO TIT
"05* "90XTOVOO"
OF- 0*00
^—-Qp-E-i- -Q.-00
QLEa 0.00
OAIRo33.76
10 ^AP_" 12500.00
~PDS-""T75cf.o6
PH20- 70*00
"" -PVS-" TO'iOQ— ' —'
BAF" 2.25
PV5H"2625*00
;L PCDS- 30.00
DF" 10.79
Au™ - 76.71
06- 10.01
HE" 7.97
,» Toj^sr ZVi'SO
PHP- 3<>B*23
Nf-HB 3.UU
^ HPI- 557.18
if p^p.. TO2VW
HF" 12.75
FC» 1*33
^_ _...... A..
LLK"9UUU.UU
^ CLMR» 3.00
n CLI^A" -- 223'9?.
CO- 1913, EC- 656500.12 _
CFP- 0*00
CORD- 965630*75
Cl- 65650.01
'„ Cl?".. 96563.07
Figure 25 SAMPLE DATA
n..._______._..._._.......--_.-.......-..----•.«»-.--•.->.
53
-------
i.
OU*UU
TW« 200*00
—TAPFfi—TI75VOD"
SLR- 44615.71
i
li
»—
It- .
J
B
>n..
!»..
54
-------
I.
V.ALI UP tOAr »UHtBO»QLCBU
\
4—•
t.
UUCnin n«T Dt KCUU*
— "9000YOO-
OF" 0*00
OLE" 0*00
Wni r»™ 3 Jt f O
CAP" 25000tOO
"— "PDfS» ..... 7900-fOO
PH20° 70*00
'— --PVS"- ....... TOiOO
BAF» 2.25
PCDS- 30.00
""" — lOTJOTTSDO
L—-AP»
OF" 10.79
«UH t lot 11
OG» ' 10.01
"—Vr- 6T7YB2T
HE" 7.97
OHP" 696.47
NFPH 3.00
HP!" 1114.36
eo4Yfio"
„. FC
tUK° 5UUU.UU
B CLMR= 3.00
"CLMS~«» SVOO"
CLMA= 447.97
II--
CO" 38269.45
"—"CPUS
CM" 59?0tl4
CP» 32733.01
APHC- 0*00
Ep-fi ......... o-;0*3
CEF" 133430.03
EC=1213000.25
CFP» 0.00
CORO=1718258.25
R r •_ i * *B"*"JiM >%•• *^ 1
CIO- 171625.81
55
-------
TW« 200.00
"PAPFfo"""2"25"6i"dO"
SLRo 89231.42
""T890.-66"
0.
it..
u
»_
56
-------
'
' ASSWETJ- 1»roGKA!TOEI)"SLVDGE"EtE MENTAL" "COMPOS IT 1 ON"
-NO-.-2-F-uet-ott: -
wATER uwErain nAY BE REGti*IN kEACTOR"
'— "OS»— "9000VOO
QF« 0.00
, _ OLE" _ 0.00
OAIR* 33.76
CAP- 37500.00
„
•"
PM20- 70.00
—~
BAF" 2.25
PVSH* I
PCDS- 30.00
-91v5^-
OF» 10.79
DG» 10.01
"VF* ...... B77Y87
HE- 7.97
„
OHP- 1044.71
II
„ HP1- 1671.54
HF» 12*75
FC" 1.33
CCR"5WOU.OU
CLMR- 3*00
"'CLM5-' -8VOO--
CLMAa 671.96
ii.
n. ..
CO" 57404.16
11 --- CM" --- 89?3.2T ------ ---
"— -XFO" ............ 65W.66
CP- 49099.50
XFO" ............ 65
APHC- 0.00
TprCa- ........ O.~03"
CEF- 194645*03
rET&«i"2-6-8r05Y36"
EC«1769500*25
CFP- 0.00
"COR-I7i69500;Z5
CORDo2437323.50
- CT*~ 1T6950T03"
CID- 243732.31
.....
Figure .29.. .SAMPIJE. DATA
57
-------
FA" OOcOO
). TW» 200«00
•pAPH.""3375VOO"
. SLR" 1338*7.12
y—-arc-
o.
-
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58
-------
I.
4
t.
IWT DC KCUU* IN KCnl I
' —
OF- 0.00
OLE" 0*00
WM«- 33* /
3 CAP* 50000*00
— — —
PH20- 70.00
•j1— "pysar ------- HTiOO
BAP- 2.25
n.
rvan*
^ PCDS- 30*00
"-"~
DF« 11*52
««• ay* ro
DG» 10*69
Vr* 7T3VIT-
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OHP- 1581*19
NFF" **00
X HPI- 2529.90
'•" "FHflFi— 'T7ZOT5V
HF- 12.75
FC- 1.33
3UUU.UW
^ CLMR- _ 3*00
0 __CLMA- 783.95
CO- 84517*48
^ CH*
1 CP« 74312.75
—"CTO" VXOVST
M APHC- 0*00
f—"Der ff.'W
CEP* 255860*03
u.
1 EC-2326000.50
*-— •
CFP» 0*00
) — 'C
CORD-3197096*00
CI» 232600*03
1 CIO- 313709*56
*—'-
59
-------
>. TW 200.00
—warns—vsffov
. SLR- 192627.31
»"
0.
>«„..
60
-------
CONCLUSIONS AND RECOMMENDATIONS
Performance of the System
The personnel at all of the installations visited were very well pleased
with the performance of the fluidized bed incineration system. Most operating
problems appeared to be caused by jamming feed systems. Both the special re-
tractable screw feed (Patent, Reference 3) and the screw pump- flexible line
feed system were subject to occasional jamming because of overdrying of the
sludge feed at the incinerator or because of silt carried into the feed system
with the sludge. The only other frequently occurring problems appeared to be
the burnout of spray nozzles or thermocouples in the bed.
The fluidized bed incinerator is uniquely qualified for applications
where liquified wastes having insufficient heating value or variable heating
value must be disposed of. The height of the freeboard determines the sa,nd
loss rate. This is a variable and should be stated with any price quotation.
Method of Rating
All of the fluidized bed incinerator contracts reviewed at FWPCA offices
had a performance specification sheet which was supplied by the manufacturer
(Dorr-Oliver) of the incineration system. These specification sheets were
seldom filled out to allow an adequate verification of any performance guarantee.
Further, it was found that the method of verifying that the systems met
the contract specifications on capacity was totally inadequate. The method
uses an empirical relationship of 1 standard cubic foot of air equals 100 BTU
at stoichiometric conditions. Therefore, the claim that the sludge burning
capacity of the incinerator can be measured by simply measuring the air flow
is in error. The discrepancy is apparent when one considers that H_ requires
1/2 mole of fip while C require 1 mole of 02 for complete combustion. However,
HP produces aoout 6^-,OQQ Btu/# and C produces only 16,000 Btu/# when completely
burned. The ratio of Btu's produced to air requirements for Hp in standard
cubic feet is thus
2I
64,000 Btu/#H <
2 mole H2° = 53,700 Btu/mole air
k.^6 (1/2 mole 0 ) moles air
One mole of air has a volume at standard conditions of 378 ft . Therefore,
53,700 Btu/mole air (9>yfl pj^ m°*f ^J = ite Btu/SCF air
The ratio for C is
12,000 Btu/#C (-
air
k,j6 (imole jZL) moles air
61
-------
Therefore,
30,200 Btu/mole air ( ? = 80 Btu/SCF air
Thus, it is seen that the air requirement per Btu of heating value of sludge
or any other fuel will vary significantly from a standard of 100 Btu/Std ft^
air. It is therefore recommended that another method (such as sludge veighing)
be used for evaluation of the burning capacity of an incinerator during
acceptance testing.
Factors Influencing Operating Costs
The effectiveness of the devatering system plays an important part in
determining the fuel requirements for a sludge incineration system. A system
with a good devatering device, of sufficiently low power requirements, can greatly
reduce the fuel requirements. At all plants visited, chemicals vere added to the
sludge prior to the dewatering device. The cost of the chemicals required was not
clearly spelled out in any contract reviewed on this project. Also, the contracts
failed to require any guarantee on fuel consumption or power consumption because
of the lack of data supplied in the contracts. The contract sheets requiring this
data were left blank in all cases. The cost of operation in dollars per pound
of volatile solids should be clearly spelled out in any such contract.
Accuracy of the Equations Developed
The equations developed on this program were based on the most accurate
information attainable from the field. There were significant variations in
system design from one plant to another.
The costs for the units surveyed did not follow the costs submitted to FWPCA
(Reference l). In most cases, the actual prices paid for the units surveyed were
significantly below the manufacturer's (Reference l). As competition from other
manufacturers increases, the prices probably will be reduced belov the prices
now in effect.
Since the above variations exist, it is recommended that the prices given
in the equations developed on this program be used as maximum prices rather than
use those suggested by the manufacturer (Reference l).
Lime Recalcination
The fluidized bed recalcination process and equipment are very similar to
that used for fluidized bed incineration of sewage sludge. It is recommended that
a mathematical model be developed for the lime recalcination process, since
phosphorous removal from sewage waste waters is fast becoming an important process.
62
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TERMINOLOGY-
Al = Moles carbon in sludge considered based on sludge elemental
composition
A2 = Moles carbon in fuel for sludge considered
A3 = Moles carbon in fuel and sludge considered
2
AF = Freeboard cross-sectional area, ft
2
AG = Grid cross-sectional area, ft
AIRCP = Heat content of combustion air @ 60°F for sludge and fuel
considered (0°F base) Btu/#
A0 = Outside surface area of incinerator freeboard and bed
sections, ft
APHC-' * System air preheater cost for maximum allowable sizing,
includes all reactors used, dollars as of Feb.^ 1968
APHS—' = Air preheater size (maximum) for complete system, BtfU/hr
Bl - Moles Hp in sludge considered
B2 - Moles Hp in fuel for sludge considered
B3 = Moles Hp in sludge and fuel considered
BAF ** Air flow rate required for combustion of sludge and
fuel at U.Qtf, excess 0L, # air/# sludge
C = Moles of 0p in sludge considered
CAP = Capacity of incinerator system, # sludge/hr
CAPI = Capacity of each incinerator reactor used in system,
# sludge/hr
CEF = Consulting Engineer's fee based on study field data
capital costs, dollars as of Feb., 1968
CEFD = Consulting Engineer's fee based on Dorr curves for
capital costs, dollars as of Feb., 1968
CF = Fuel cost for QFP for 1 year, current dollars, no. preheat
a/ Mote: # is an abbreviation used for pounds.
b/ APHCI and APHSI refer to a single incinerator system in a multiple
incinerator installation.
63
-------
CF0 = Cost of fuel to operate, current dollars, not including
startups, including heat loss from incinerator(s), $/yr
(v/wo preheat)
CFP = Yearly cost of fuel replaced by air preheaters, current $/yr
CI = Installation cost based on study, $-Feb,, 1968
CID = Installation cost based on Dorr curves, $-Feb., 1968
CL = Cost of operating labor per yr, current dollars, $/yr
CLM = Total cost of maintenance labor, current dollars, including
overhead, $/yr
CLMA = Total cost of maintenance service labor, $/yr, current
dollars, incl overhead
CLMR = Maintenance labor ratea current dollars, $/hr
CLMS = Maintenance service labor ra+.n, current dollars, $/hr
CLR = Operating labor cost, current dollars, $/yr « $/8?50 man hrs
CM = Cost of maintenance, current dollars, $/yr
C0 = Cost of operation, current dollars, $/yr
C0R = Cost of Reactor System less preheat based on field data,
$-Feb., 1968
C0RD = Cost of Reactor System less preheat, Dorr curves, $-Feb., 1968
CP = Cost of electrical power, current dollars, $/yr
CPC20 = Heat content of C^> in exhaust @ 1^00°F for sludge and fuel
considered, Btu
CPH20 = Heat content of H^> in exhaust @ lUOOGF for sludge and fuel
considered, Btu
CPIN = Heat content of inerts @ 1^00°F
CP2N = Heat content of N in exhaust @ 1UOO°F, for sludge and fuel
considered, Btu
CP20 = Heat content of 0 in exhaust @ 1^00°F, for sludge and fuel
considered, Btu
CSL = Cost of sand loss, current dollars, $/yr
D = Moles of Np in sludge considered
6U
-------
DF •= Diameter of freeboard, ft
DC = Diameter of grid, ft
DQ = Difference between makeup heat required to burn sludge
and maximum air preheater heat available, Btu/hr
EC = Equipment cost including preheat(s) based on field data,
dollars as of Feb., 1968
ECD = Equipment cost including preheater(s) based on Dorr curves,
dollars as of Feb., 1968
EPC = Cost of 1 KM hour of electrical power, current dollars, 4/KW hr
FBHP = Fluidizing blower HP for system
FBHPI = Fluidizing blower HP for each incinerator in system
FC = Cost of fuel, '68 $/l,000,000 Btu
FM = Mole multiplier for fuel
HE = Depth of expanded bed, ft
HF = Height of bed freeboard required, ft
HP = Height of plenum required, ft
HPI = Installed HP for system
HPII = Installed HP for each incinerator in system
NFP = Number of feel points" per incinerator
0HP = Operating HP for system
0HPI = Operating HP for each incinerator in system
0RH = Overall reactor height, ft
PAPH = Pounds ash generated per hour of operation, #/hr
PCI = Preheater maximum heat transfer rate to air from exhause
products l400°F inlet to 400°F exit, C = const., Btu/hr
PC2 = Preheater maximum heat transfer rate to raise air temperature
to 1000°F, Btu/hr
PC3 = Allowable maximum heat transfer in air preheater JLimited. by
PCI or PC2, Btu/hr
-------
PCDB = Percent dry solids/100, # dry solids/# sludge
PCTY = Fraction of year, week or month to be operated, hrs operated/
hrs yr (total hrs, not work hrs)
PDB = Pounds of dry solids per hour capacity of system, #ES/hr
PDBI = Pounds of dry solids per hour capacity of each incinerator
in system, #DS/hr
PDBC = Pounds of dry solids under consideration from sludge elemental
analysis considered, #
PH20 = Percent HO in sludge
PPH20 = Pounds HO under consideration from sludge elemental analysis
considered, #
PS = Total pounds of sludge from sludge elemental analysis
considered, #
PV = Plenum volume for each incinerator, ft
PVS = Percent volatile solids in sludge, ^weight
P0VS = Pounds volatile solids under consideration from sludge
elemental analysis, #
PVSH = Pounds volatile solids/hr capacity of system
PVT = Theoretical product volume, moles combustion products from
system
= Moles combustion products @ k% excess 02 from system
QAIR = Input heat from combustion air @ 6o°F, Btu/# sludge
QE = Heat content of combustion products and inerts leaving
incinerator at l400°F, Btu/# sludge
QF = Heat required from fuel to burn sludge adiabatically with
no preheat at lUOO°F and 4.0$ excess 0p, Btu/# sludge
QFP = Heat required from fuel and preheat to burn sludge at
ltOO°F (QF + OPE), Btu/# sludge
QFU = Higher heat of combustion of fuel, Btu/# fuel
QL = Heat loss from combustion system by radiation and convection,
which must be supplied by the heat of combustion, Btu/# sludge
CJLE = Heat loss from pilot test combustion equipment by radiation
and convection, Btu/# sludge
66
-------
QLL
OPE
OS
QSL
SCP
SLR
SUN
SUMQ
TA
TCN0
THCP
THCFT
TSC
TSCD
TW
Calculated heat loss from A0 (neglecting radiation), Btu/hr
Heat supplied to preheated air during pilot test Tor fuel
determination, Btu/# sludge, or heat content of air entering
bee (0°F base)
Total sludge heat input (higher heating value), Btu/# VS
Total sludge heat input (higher heating value), Btu/# sludge
Heat content of sludge 6dcF (sludge considpr°d in elemental
analysis), Btu
Sand loss rate from bed, #/hr
Difference between heat content of exhause products 1^00°F
and heat input from sludge, fuel and air considered, Btu/# sludge
Total heat content of exhause products based on specific heats
@ 1UOO°F, Btu/# sludge
Contract ambient air temperature surrounding incinerator
(if unspecified, use 60°F), °F
System annual maintenance and operating cost, current dollars
Total heat content of exhaust products @ l400°F = SUM^/PS,
Btu/# sludge
Total heat input to sludge from combustion and supply air
and sludge, Btu/# sludge
Total system cost based on field data, dollars as of Feb., 1968
Total system cost based on Dorr curves, dollars as of Feb., 1968
Contract wall temperature of incinerator (use 200°F if unspecified),
VE
VS
XF
Y
ZI
ZII
Volume of expanded sand bed required, ft
Static volume of sand bed required, ft
Moles N5 in theoretical fuel and sludge air for sludge elements
(composition considered)
Excess moles 02 required to reach U$ excess 0g
Design pounds of volatile solids each fluidized bed incinerator
in the system handles, #VS/hr
Number of incinerators, in the system, required to handle the
slude capacity at no more than 1500 # VS/hr per incinerator
67
-------
REFERENCES
1. Dl Gregorio,D:, "Information Development for Waste Treatment Processes",
.Contract lU-12-60, FWPCA, Progress Report No. 11, May, 1968.
2. Albertson, 0. E., "Low Cost Combustion of Sewage Sludges", Water
Pollution Control Federation, October 8, 1963.
3- Albertson, 0. E., "Fluidized Bed Combustion System", Patent Filed
December 8, 1966, Released January 30, 1968, Wo. 3,366,080.
68
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BIBLIOGRAPHY
1. Anderson, T. B. and Jackson, R. , "A Fluid Mechanical Description of
Fluidized Beds", I & EC Fundamentals. Vol. 6, No. k, November 1967,
p. 527-
2. Stevens, J. I., "Fluidized Bed Incinerator: R for Handling Oily
Sludges", Water and Wastes Engineering, September 1966, p. 82.
3- Narsirahan, G. , "On a Generalized Expression for Prediction of Minimum
Fluidization Velocity", A.I.Ch.E. Journal, May 1965, p. 550.
k. Wen, C. Y. and Yr, Y. H., "A Generalized Method for Predicting the
Minimum Fluidization Velocity".
5- Leung, P. K. and Quon, D. , "A Computer Model for Moving Beds - Chemical
Reaction in Fluid Phase Only", The Canadian Journal of Chemical
Engineering, February, 19^5 > p. ^5.
6. "Fluid Bed Incinerators Studied for Solid Waste Disposal", Environ-
mental Science and Technology , Vol. 2, No. 1, July 1968, p. 595-
7- Fair, Geyer and Okun, Water and Wastewater Engineering (Volume 2),
John Wiley and Sons, Chicago, 1968.
8. Proudfit, D. P., "Selection of Disposal Methods for Water Treatment
Plant Wastes", Journal AWWA, June 1968, p.
9- Fair, G. M. , Moore, E. W. , "Heat and Energy Relations in the Digestion
of Sewage Solids", Sewage Works Journal, March 1932, p. 242.
10. Owen, M. B., "Sewage Solids Combustion", Water and Sewage Works,
October 1959-
11. Millward, R. S., Booth, B. B., "Incorporating Sludge Combustion into
Sewage Treatment Plant", Water and Sewage Works, 168, p. R-169.
12. Landrock, A. H., "Fluidized Bed Costing with Plastics: Technology
and Potential for Military Applications", Plastics Technical Evaluation
Center, Picatinny Arsenal, Dover, N. J., January 196k, D. D. C.
13. Gilbert, L. 0., "Organic Coating Using the Fluidized Bed Technique",
Rock Island Arsenal, Rock Island, 111., September 20, 1962, D.D. C.
-------
BIBLIOGRAPHY ( CONT.)
27. Smith, A. R., "Incineration of Sludge-Some Governing Principles",
Sevage Works Journal, Vol. II, 1939, p. 35-
28. "Three Ways to Dispose of Sewage Sludge", Engineering, 24 November 1967,
p. 828.
29. Dayan, Y. et. al., "Heat Transfer Efficiency in a Fluidized Bed",
The Canadian Journal of Chemical Engineers, December 1966, p. 330.
30. Buckham, J. A. and Levitz, N. M. , "Fluidized Bed Technology",
A.I.Ch.E., 1966.
31. Legler, B. M. , "Feed Injection for Heated Fluidized Beds", Chemical
Engineering Progress, Vol. 63, Wo. 2, February 1967* P- 75-
32. Halwagi, M. and Gomezplata, A., "An Investigation of Solids Distribution,
Mixing, and Contacting Characteristics of Gar-Solid Fluidized Beds",
A.I.Ch.E. Journal, Vol. 13, No. 3, p. 503-
33. Geldart, D., "Gas-Solid Reactions in Industrial Fluidized Beds",
Chemistry and Industry, 13 January 1968, p. hi.
3k. "Free Fall, Fluid-Bed Setup Gasifies Coal", C and EN, September 25, 1967,
P- 72-
35. Holmes, J. T. et. al., "Fluidized Bed Disposal of Fluorine", I and EC
Process Design and Development, Vol. 6, No. k, October 1967, p.
36. "I and EC Reports and Comments", Industrial and Engineering Chemistry,
Vol. 59, No. 10, October 1967,- p. 11.
37. "Photography Shows Fluidized- Bed Properties", C and EN, October 23, 1967,
P- 67.
38. Priestly, R. J., "How Good is the Fluosolids Reactor", Rock Products,
"July 1965, p. 72.
39- Anderson, T. B. and Jackson, R., "Fluid Mechanical Description of
Fluidized Beds", Industrial and Engineering Chemistry, Vol. 7, No.l,
February 1968, p. 12.
70
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BIBLIOGRAPHY (COM1.)
UO. Romero, J. B. and Smith. D. W., "Flash X-Ray Analysis of Fluidized
Beds:, A.I.Ch.E. Journal. Vol. 11, No. h, July 1965, p. 595.
ill. Wolf, D. and Resnick, W., "Experimental Study of Residence Lime
Distribution in a Multistage Fluidized Bed", I and EC Fundamentals,
Vol. k, No. 1, February 1965, p. 77.
k2. Jonke, A. A. , et. al., "Candidate for Second-Generation Fuel-Reprocessing
Plants". Nucleonics, Vol. 25, No. 5, May 1967, p. 58.
1*3. Petrie, J. C. and Black, D. E., "Dry Collection and Disposition of
Solids from Fluidized Bed Off-Gas", Atomic Energy Division, PhillJps
Petroleum Company, Contract AT(lO-l)-205, July 1964.
kk. Sawyer, C. N., Kah, P. A., "Temperature Requirements for Odor Destruction
in Sludge Incineration", Journal W. P. C. F., Vol. 32, No. 12, December 1960.
k^. Ridgeway, K., Segovia Ing Quim, E., "Fluidization and Gas Suspension
Techniques in Pharmaceutical Manufacturing", Manufacturing Chemist
and Aerosol News, December 1966.
k6. Marks, L S., "Mechanical Engineers Handbook", Fifth Edition, McGraw-
Hill, p. 733-
kj. DiGregorio, "Information on Development for Waste Water Treatment
Processes", Contract 1^-12-60 FWPCA, Progress Report No. 11, May 1968.
U8. Albertson, 0. E., "Low Cost Combustion of Sewage Sludges", Water
Pollution Control Federation, October 8, 1963.
71
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PATENTS FOUND ON FLUIDIZED BED INCINERATOR EQUIPMENT
1. Albertson, 0. E., "Disposal of Waste Material by Combustion in an
Inert Fluidized Bed", Filed March 31, 196U, Released May 16, 196?,
No. 3,319.587-
2. McKay, J. B., "Reactor Furnaces", Filed June 26, 1951, Released
August 16, 1955, No. 2,715,565.
3. Booth, P. B., "Gas Scrubber", Filed August 27, 1958, Released
June ll*, I960, No. 2,9^0,51*0.
k. Doyle, H.j "Gas Scrubber", Filed April 12, 19^9, Released December 16,
1952, No. 2,621,75^.
5. Albertson, 0. E., "Waste Burning System with Internal Screen
Deliquifiers", Filed April 23, 1966, Released April 2, 1968,
No. 3,375,79^.
6. Albertson, 0. E., "Fluidized Bed Combustion System", Filed December 8,
1966, Released January 30, 1968, No. 3,366,080.
72
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