EPA-600/2-75-014

August 1975
Environmental  Protection Technology Series
                               SINTER PLANT
            WINDBOX  GAS  RECIRCUUT10N
                  SYSTEM DEMONSTRATION
                     PHASE 1  ENGINEERING AND DESIGN
                               U.S. Environmental Protection Agency
                                Office of Research and Development
                                     Washington, 0. C. 20460

-------
                                    EPA-600/2-75-014
            SINTER  PLANT

WINDBOX  GAS  RECIRCULATION

    SYSTEM  DEMONSTRATION

      PHASE 1.  ENGINEERING AND  DESIGN

                     by
                D. A. Pcngidore
             National Steel Corporation
                 P.O. Box 431
            Weirton, West Virginia 26062
              Contract No. 68-02-1364
               ROAP No. 21AQR-005
            Program Element No. 1AB015
        EPA Project Officer: Robert C. McCrillis

      Industrial Environmental Research Laboratory
        Office of Energy, Minerals, and Industry
      Research Triangle Park, North Carolina 27711
                  Prepared for

      U.S. ENVIRONMENTAL PROTECTION AGENCY
          Office of Research and Development
              Washington, D.C.  20460

                  August 1975

-------
                        EPA REVIEW NOTICE

This report has been reviewed by the National Environmental Research
Center - Research Triangle Park, Office of Research and Development,
EPA, and approved for publication.  Approval does not signify that the
contents necessarily reflect the views and policies of the Environmental
Protection Agency, nor does mention of trade names or commercial
products constitute endorsement or recommendation for use.
                   RESEARCH REPORTING SERIES

Research reports of the Office of Research and Development, U.S. Environ-
mental Protection Agency, have been grouped into series.  These broad
categories were established to facilitate further development and applica-
tion of environmental technology.  Elimination of traditional grouping was
consciously planned to foster technology transfer and maximum interface
in related fields.  These series are:

          1.  ENVIRONMENTAL HEALTH EFFECTS RESEARCH

          2.  ENVIRONMENTAL PROTECTION TECHNOLOGY

          3.  ECOLOGICAL RESEARCH

          4.  ENVIRONMENTAL MONITORING

          5.  SOCIOECONOMIC ENVIRONMENTAL STUDIES

          6.  SCIENTIFIC AND TECHNICAL ASSESSMENT REPORTS

          9.  MISCELLANEOUS

This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series.  This series describes research performed to
develop and demonstrate instrumentation, equipment and methodology
to repair or prevent environmental degradation from point and non-
point sources of pollution.  This work provides the new  or improved
technology required for the control and treatment of pollution sources
to meet environmental quality standards.
This document is available to the public for sale through the National
Technical Information Service, Springfield,  Virginia 22161.

                Publication No. EPA-600/2-75-014
                                 11

-------
                    PHASE 1 - FINAL REPORT ABSTRACT

Windbox gas recirculation, as applied to a sinter plant, involves the
return of a portion of the windbox exhaust gas to a hood above the
sinter bed.  The objective is to reduce the volume of waste gas to be
cleaned and to conserve a part of the sensible heat in the windbox
exhaust gas.

This report develops the tradeoffs of gas recycle ratio versus oxygen
content, moisture content, and temperature of the gases above the bed;
total power consumption; and other important parameters.  The bases for
this study, and the full scale design developed therefrom, are operating
and emissions data taken from two large modern sinter plants.  Recycling
is projected to reduce hydrocarbon emissions to acceptable levels at
reduced power consumption and capital cost relative to more conventional
approaches.  The advantages and disadvantages of various devices for
final control of particulates were studied with the final choice for
evaluation being a gravel bed filter.

This report describes Phase 1 of a two-phase project.  Phase 2 will
consist of extensive testing and evaluation of a full scale windbox gas
recirculation system and a gravel bed final gas cleaning system in-
stalled at the National Steel Corporation, Weirton Steel Division,
sinter plant.

This report was submitted, in fulfillment of contract number 68-02-1364,
by the National Steel Corporation, Weirton Steel Division, under the
partial sponsorship of the Environmental Protection Agency.  Work was
completed as of March, 1975.
                                   iii

-------
                               CONTENTS




                                                       PAGE









ABSTRACT                                                iii




CONTENTS                                                 iv




LIST OF FIGURES                                           v




LIST OF TABLES                                           vi




ACKNOWLEDGEMENTS                                       viii
SECTIONS









I         CONCLUSIONS                                     1




II        RECOMMENDATIONS                                 2




III       INTRODUCTION                                    3




IV        TECHNOLOGY REVIEW                               6




V         BASELINE MEASUREMENTS                    .      25




VI        PROCESS DESIGN                                 59




VII       TEST PROGRAM DESIGN                            83




VIII      REFERENCES                                     86




IX        BIBLIOGRAPHY                                   87




X         APPENDICES                                     98
                                   iv

-------
                            LIST OF FIGURES


NO.                                                         PAGE


 1   GAS RECIRCULATION SYSTEM - GENERAL ARRANGEMENT           5
 2   SCHEMATIC FLOW DIAGRAM FOR A TYPICAL MODERN
       SINTER PLANT                                           9
 3   PLAN VIEW OF FIELD SAMPLING LOCATIONS                   27
 4   SAMPLING TRAIN FOR PARTICULATE DETERMINATIONS           29
 5   SAMPLING TRAIN FOR SO  DETERMINATIONS                   31
                          X
 6   SAMPLING SYSTEM FOR OXIDES OF NITROGEN
       DETERMINATIONS                                        32
 7   GAS RECIRCULATION SYSTEM - FLOW DIAGRAM              74 & 75
 8   GAS RECIRCULATION SYSTEM - GENERAL ARRANGEMENT          77
 9   GAS RECIRCULATION SYSTEM - PLAN                         78
10   GAS RECIRCULATION SYSTEM - NORTH ELEVATION              79
11   GAS RECIRCULATION SYSTEM - CROSS SECTION THRU
       MACHINE                                               80
                                   v

-------
                            LIST OF TABLES










NO.                                                         PAGE









 1   MATERIAL CONSUMPTION TRENDS                              13




 2   NATIONAL STEEL SINTER PLANT DESIGN DATA             16,17,18,19




 3   CHEMICAL COMPOSITION OF RAW MATERIALS                    20




 4   SINTER MIXES - YEARLY AVERAGE         ,                   21




 5   PLANT PRODUCTION DATA                                  36,37




 6   SYSTEM OPERATIONAL DATA                                40,41




 7   MAIN EXHAUST STACK GAS COMPOSITION DATA                44,45




 8   SINTER BREAKER AREA GAS COMPOSITION DATA               46,47




 9   HOT SCREENS AREA GAS COMPOSITION DATA                  48,49




10   PARTICULATE EMISSIONS DATA                             52,53




11   EMISSIONS CHEMICAL COMPOSITION                         54,55




12   FIELD TEST SUMMARY                                     56,57




13   FIELD TEST SUMMARY                                       58




14   SUMMARY OF CALCULATED DATA                             62,63




15   SUMMARY OF STACK TEST DATA                              100
                                   vi

-------
NO.                                                         PAGE









16   PARTICULATE EMISSIONS DATA                              101




17   SINTER MIX COMPOSITION                               102,103




18   WINDBOX GAS FLOW AND TEMPERATURE (EXISTING SYSTEM)   104,105




19   WINDBOX GAS FLOW AND TEMPERATURE (EXISTING SYSTEM)   106,107




20   AVERAGE WINDBOX GAS COMPOSITION                         108




21   MOISTURE CONTENT IN WASTE GAS MAIN                      115




22   DUCTWORK HEAT LOSS                                      117




23   GAS COMPOSITION                                         129
                                   vii

-------
                            ACKNOWLEDGMENTS


The following personnel and organizations are recognized for their
contribution and assistance in preparation of this report:

National Steel Corporation:

  Great Lakes-Division:

  Mr. C. Jackimowicz     -  Project Director
  Mr. R. S. Ajemian      -  Asst. Project Director
  Mr. J. W. Thomas       -  Asst. Project Director

  Weirton Steel Division:

  Mr. D. A. Pengidore    -  Project Director
  Mr. G. P. Current      -  Asst. Project Director
  Mr. D. A. Velegol      -  Asst. Project Director

Research and Development Division:

  Mr. K. P. Mass

Arthur G. McKee & Company

Dravo Corporation

Environmental Protection Agency:

  Mr. R. C. McCrillis    -  Project Officer
                                   Vlll

-------
                               SECTION I
                              CONCLUSIONS

A sinter plant windbox gas recirculation system was designed and
installed on the Weirton Steel Division No. 2 Sinter Strand.  The
waste gas recirculation design point for this system was 39%.

No design or installation barriers to the successful use of waste
gas recirculation have become apparent.

A twenty-four module gravel bed filter system, sized to handle
approximately 50% of the waste gas, has been selected for full
scale evaluation as a final particulate removal system prior to
discharging the waste gas to the atmosphere.

-------
                              SECTION II
                            RECOMMENDATIONS

It is recommended that the recirculation system be evaluated and that
the test data be used in the selection of a final gas cleaning method.

The fine, noncombustible particulate matter remaining in the gas stream
after recycling, can be removed by commercially available gravel bed
filters, wet scrubbers, dry precipitators, wet precipitators, or bag
house filters.

Information gathered during tests at the Weirton Steel Division in-
dicates that a gravel bed filter will remove these particles at lower
capital and operating costs and provide the reliability of operation
required in modern sinter plants producing high basicity sinter.  There-
fore, it is further recommended that a gravel bed filter be tested on a
full scale sinter plant windbox discharge, both with and without waste
gas recycling.

-------
                              SECTION III
                             INTRODUCTION

During the past twenty years pollution control for sinter plants has
consisted of removing particulate matter in rotoclones or cyclones
in the exhaust gas circuit between the windboxes and the discharge
stack.  These devices have also been used to recover dust generated in
the sinter cake breaker area.

The recirculation of sinter machine waste gas that has passed through
the rotoclones or cyclones back to a hood above the sinter bed is a
new technique for the removal of combustibles and a portion of the
particulate matter prior to discharge via a stack to atmosphere.

The objective of this project is to develop a waste gas recirculation
system to improve the environmental consequences of discharging sinter
plant waste gases to the atmosphere.  Primary goals for improvement
include reduction of hydrocarbons, particulates, and the volume of
waste gas.

Four National Steel Corporation Divisions have supported this develop-
ment, namely, the Granite City, Great Lakes, and Weirton Operating
Divisions and the Research and Development Division.  Each of the
operating divisions is confronted with similar emission problems
because of the similarity of their sinter plants.  Chronologically,
this EPA contract was first awarded to the Great Lakes Steel Division,
which began this program in cooperation with the Granite City Steel
and Research and Development Divisions.  The first part of the project

-------
consisted of background surveys, field sampling and project prepara-
tion.  At this juncture it became necessary for the Great Lakes Steel
Division to install final pollution abatement equipment on their
sintering plant.  The timing of this requirement interfered with the
development of the gas recirculation system at this location.

The contract was then transferred to the Weirton Steel Division which
had a prior interest in this system, had followed the Great Lakes
work, and had advanced to the design stage prior to the transfer.
Subsequently, the Weirton Steel Division completed the second part
of the project, which included the concept and design engineering,
equipment selection, detail engineering, and preparation of the final
report.  The test system was installed on the No. 2 Sinter Strand at
the Weirton Steel Division.  Construction was completed July 28, 1975.

The background work for this project involved a study of sintering and
pollution control techniques presently in common use throughout the
steel industry and the evaluation of the pollution problem by sampling
and analysis.  This subsequently led to the design, specification, and
installation of equipment.

The report also describes a test program to be used for the future
evaluation of the gas recirculation system.

Figure 1, General Arrangement of System, illustrates the components
in the gas recirculation system.

-------
                                                    RECYCLE HOOD
               WASTE GAS
             CONTROL HOUSE
                      Figure 1. General arrangement of system

WEIRTON STEEL DIVISION SINTER PLANT GAS RECIRCULATION SYSTEM

-------
                              SECTION IV
                           TECHNOLOGY REVIEW
INTRODUCTION

Sintering, as applied in the steel industry, may be defined as a process
in which iron-bearing raw materials of a fine particle size are con-
verted into coarse agglomerates by partial fusion.  The product has a
porous, cellular structure resembling clinker in physical appearance.
Its mineralogy may be substantially different from that of the original
iron-bearing fines.

Blast furnace sinter is categorized as acid or basic, depending on the
basicity ratio*.  Sinter with a basicity ratio of less than 1.0 is
acid and that with a ratio greater than 1.0 is basic.  It has become
common to refer to sinter with a basicity ratio of approximately 1.0 as
self-fluxing, while ratios in excess of 1.0 may be called burden-fluxing
or super-fluxed sinter.  Acid sinters of basicity less than 0.5 were
predominant until the early 1950's.  It was then realized that economic
and productive benefits to the blast furnace could be realized by in-
corporating in the sinter a part or all of the required furnace flux.
This was achieved by the addition of limestone and/or dolomitic fines to
the ore fines to be sintered.
,.,  . ._  _   .     Wt. Percent CaO + Wt. Percent MgO
*BasxC1ty Ratxo = Wt. Percent si02+Wt. Percent Al

-------
PROCESS DESCRIPTION

In sintering, a shallow bed of fine particles is agglomerated by heat
exchange and partial fusion of the quiescent mass.  Heat is generated by
the combustion of a solid fuel contained within the bed of fines being
agglomerated.  The process is initiated by igniting the fuel at the top
surface of the bed, after which a thin, high temperature combustion,zone
is drawn downward through the bed by an induced draft.  Within this
zone, the surfaces of adjacent particles are at a fusion temperature and
the gangue constituents form a semi-liquid slag.  The flow of volatiles
and incoming air creates a frothy condition and freezes the trailing
edge of the advancing fusion zone.  The product then consists of par-
ticles of ore bonded in a slag matrix of cellular structure.

In the ferrous industry, the material to be sintered consists essential-
ly of a mixture of iron-bearing fines and a solid fuel.  The iron-
bearing constituents are chiefly iron ore fines, recycled sinter fines
and blast furnace flue dust, but may also include mill scale, BOP dust
and other steel mill waste products containing iron.  Coke breeze is the
most common solid fuel, but other carbonaceous materials are used.  It
has become common practice to add limestone or dolomitic fines to the
sinter mix and this material may now be considered as an essential
constituent in a typical sinter mix.  This mixture of fine material is
placed on the sinter strand in a shallow bed, seldom less than 152 mm  (6
inches) nor more than 508 mm  (20 inches) in depth.  In the ignition
zone, the surface of the bed is heated to about 1260 to 1371°C (2300-
2500°F), combustion of the fuel is initiated, and fusion of the fine
particles at the surface begins.  As air is drawn through the bed, the
high temperature zone of combustion and fusion moves downward through
the bed and produces the bonded, cellular structure.

Combustion of the solid fuel and propagation of the fusion zone through
the bed is dependent on the air flow.  To assure an adequate air

-------
flow, the sinter mix is generally preconditioned to improve its perme-
ability.  This can be accomplished by eliminating excessively fine
materials when economically possible, but is normally achieved by the
addition of coarse (12.7 mm by 3.2 mm [1/2 inch by 1/8 inch]) sinter
returns and by fluffing and/or micropelletizing the fine particles in a
balling drum.
PLANT FLOW DIAGRAM

The design and physical arrangement of sintering equipment and the flow
pattern of raw materials and product differ considerably between various
plants.  The choice of equipment and material flow is generally deter-
mined by the desired capacity, space available, capital costs and pre-
vailing technology.  However, each plant can be divided into three
distinct phases of operation, namely, (1) raw materials processing, (2)
sinter production and (3) product processing.  A schematic flow diagram
of a typical modern sinter plant is shown in Figure 2.

The inbound raw ore is first screened to the maximum size desired for
the blast furnace coarse ore.  The oversize ore is then crushed.  After
a second screening at 9.5 to 12.7 mm (3/8 to 1/2 inch), the oversize is
sent to the blast furnace stock house and the undersize is conveyed to
the sinter plant storage bins.  A separate raw materials system handles
the balance of the materials, such as flue dust, limestone, coke breeze,
mill scale, etc.  Except for the coke breeze, these materials are suf-
ficiently fine for sintering and are conveyed directly to the sinter
plant storage bins.  The coke breeze is usually ground in a rod mill
prior to storage, although other size reduction techniques are sometimes
used.  Most modern plants are so arranged that the various screens,
crushers, etc., can be bypassed if not required.  From the raw materials
storage bins, the desired materials are fed at a specified rate onto a
common collector belt.  Included in this material are the hot and cold

-------
FER
¥
c

L
(-
CRUSHER /\,
(+) ORE
' SCREEN
l(-)


(-

X TRANSFER CAR T0
1 	
COARSE

°REp- BALLING DRUM - ^^

»^ Tf\ UCADTH
i ^ IU HhAKIn
SCREEN ^ S1NTER C<

LAYER
)OL ER ^

(+)
ORE
\ SCREEN
/ *- '
BLAST FURN

R.R. CAR-i
RAW l\S"\S
ORE , 	 . /\\/T\
ROD 1
mil *


ACE * [

t

IR

- t S~
S
i
HOT
t t t * t + r.nin
ON MATERIALS BIN COKE LIME RETURN
1 ' ' ' ' * .,.__!
)HOT RETURNS
SURGE BIN
(\ _ ... 	 	 	 |
, -. 1 RN IT 1 (IN
S NTFR MAP.HINF FIIRNACF -.
+ V SCREEN j
WYYYYYYY t TYYTTTTYTYTT


SINTER BR
FAKER-' '
tAl^tK POLLUTION
CONTROI
     COOLING  FAN
                                              SINTER FAN
Figure 2.   Schematic  flow diagram for typical modern sinter plant

-------
sinter return fines, generally fed from storage bins.  Some plants do
not have storage or surge capacity for hot returns, while others may be
capable of adding the return fines at a later stage in the raw materials
processing.  The feed materials are then generally fed to a mixer,
commonly a pug mill or a belt mixer.  Some plants utilize only mixers,
while other plants use pelletizing discs or drums which promote both
mixing and micro-balling.  Moisture for proper conditioning of the feed
is added in the mixer and/or balling facility.  The mixed and micro-
pellet ized feed is then conveyed to the sinter strand.

The sinter production phase of the operation occurs entirely on the
sinter strand.  Prior to feeding the raw mix, a grate layer of interme-
diate size sinter, usually finer than 25.4 mm (1 inch) and coarser than
6.35 mm (1/4 inch), is fed onto the machine grate to a depth of 25.4 to
50.8 mm (1 to 2 inches).  This is done to reduce the temperature to
which the grate bars are exposed, which extends grate bar life, and to
reduce the amount of fine material passing through the grate bars.  The
raw mix is fed directly onto the grate layer to a predetermined bed
depth and ignited in the ignition furnace fired with gas or oil.  Once
ignited, the induced draft draws the combustion zone down through the
material bed.  The process is complete when the combustion zone has
burned through to the grate layer.  The speed of the machine is control-
led so that the burn-through reaches the grate layer as the material is
ready to pass over the discharge end of the machine.  The proper speed
is determined by observing the sinter bed at the machine discharge and
monitoring the maximum waste gas temperature in the next to last wind-
box.

Product processing begins at the discharge of the strand where the large
cakes of sinter pass through a rotary breaker.  The large cake is
reduced to a maximum size of 203 to 305 mm (8 to 12 inches) to facili-
tate cooling.  The fines generated from this crushing operation are
removed by a hot screen and recycled to the raw mix feed, while the
                                   10

-------
oversize is sent to the cooler.  There are several types of coolers, all
of which function to reduce the temperature of the sinter so that it may
be subsequently handled without damage to the conveying equipment.
After the cooler, the sinter is cold screened, usually into three size
consists.  The smallest size consist, usually minus 9.5 mm or 6.35 mm
(3/8 inch or 1/4 inch), is recycled as cold return fines.  A portion of
the intermediate size is recycled as grate layer.  The excess over the
grate layer needs is sent to product storage.  The coarsest size is the
preferred product for blast furnace feed.  A large bin capacity is
usually provided for loading out the sinter for the blast furnace stock
house bins or storage yard.

These process and material flow descriptions are typical of a modern
sinter plant and essentially describe the Great Lakes sinter plant.
Many of the older plants lack certain features, such as hot and/or cold
screens, balling facilities, sinter breakers, coolers, and flexibility
in materials handling.  Some of the newest plants may have special
features for additional process control such as:

1.   Raw materials proportioning systems.  Raw materials bins may be
     equipped with controllable weigh feeders to maintain a constant
     weight proportionality for feed materials.  This stabilizes the
     process and reduces the variation in product chemical composition.

2.   Crushing of hot returns.  This provides additional control over the
     size of hot returns which must be recycled.

3.   Crushing of sinter prior to cold screening.  This provides a
     closely sized product for blast furnace consumption and improves
     the final product strength by degrading the weaker particles prior
     to cold screening.  However, this increases the quantity of mate-
     rial which must be recycled.  In some cases, the oversize sinter
     from an initial cold screening is crushed, with a subsequent
                                   11

-------
     secondary screening to remove the fine material generated.

4.   Preconditioning of feed materials.  Special circuits may be used to
     condition fine materials, such as steelmaking dusts, blast furnace
     filter cake and internal dusts from the sinter plant prior to
     introducing these materials into the main sinter mix.

5.   On-strand cooling.  The length of the sinter strand is increased so
     that some or all of the normal cooling is done on the strand rather
     than in a separate cooler.  This eliminates the hot screening
     operation, although the single facility may be more complex.

6.   Computer control of the process.  Computers are used for process
     control in a number of foreign sinter plants and in at least two
     domestic plants.

Of these, items 1, 3 and 6 are the most commonly encountered new fea-
tures, with item 4 gaining importance as the incentive and need to
recycle fine iron-bearing waste materials is accented.
MODE OF SINTER PLANT OPERATION

Most sinter plants are generally operated in a similar manner, differing
primarily in the characteristics of the raw materials which must be
processed and the basicity ratio chosen for the sinter product.  The
method of operating the sinter process and the effects of operating
variables have been reported in the literature (1,2)*.

The general trend in materials used for sintering has been toward less
iron ore fines and more iron-bearing waste materials such as mill
scale, ironmaking dusts and slags.  Fluxstone additions have increased

*See Section VIII, References.
                                   12

-------
                                TABLE I


MATERIALS USED IN THE PRODUCTION OF SINTER AT STEEL PLANTS IN THE

UNITED STATES
MATERIAL
Iron Ore
Flue Dust & Sludge
Scale
Cinder and Slag
Other
Fluxstone
Fuel
Year
1960
a) 35,900
b) 36,500
c) 74
5,200
5,300
11
980
1,000
2
49
50
.01
490
500
1
3,740
3,800
7
2,360
2,400
5
1964
39,370
40,000
69
4,530
4,600
8
2,170
2,200
4
394
400
1
1,080
1,100
2
5,800
5,900
10
3,250
3,300
6
1968
33,170
33,700
64
3,050
3,100
6
3,150
3,200
6
394
400
1
1 ,770
1,800
3
7,480
7,600
15
2,660
2,700
5
a) Thousands of metric tons
b) Thousands of gross tons
c) Percentage of mix
                                   13

-------
with the trend toward higher sinter basicities.  Table 1 shows the trend
in sinter feed materials between 1960 and 1968 (3).   The increased use
of mill scale, cinder and slag, other materials which are primarily
recyclable iron-bearing fines, and fluxstone is evident.  The reduction
in the use of blast furnace flue dust and sludge is due to improved
blast furnace burdens.

A major factor influencing sinter plant operation has been the trend
toward higher sinter basicities.  In 1962, only about 40 percent of the
sinter produced had a basicity ratio in excess of 1.0 (4).  At the
present time, available data indicate that at least 85 percent of the
sinter produced in the United States and Canada has a basicity in excess
of 1.0 (5).  Moreover, at least six sinter plants regularly produce
sinter with a basicity ratio greater than 3.0 and one plant in excess of
4.0.  Increasing the sinter basicity generally reduces production
capacity but increases the strength of the sinter product.  Improved
sinter quality reduces the quantity of fines to be recycled in the
sinter plant and decreases the flue dust and sludge generated at the
blast furnace.  Higher basicity sometimes improves sinter strand opera-
tion and reduces the production and emission of fine dusts.  However,
higher basicity makes the choice of pollution control equipment more
difficult (6).
NATIONAL STEEL FACILITIES AND PRACTICE

The process flow sheet for both the Great Lakes and Weirton No. 2
sinter plants is similar to that shown in Figure 2 except that neither
plant has hot returns surge capacity.  The Weirton No. 1 sinter plant
has no hot returns surge capacity and has a primary and secondary pug
mill rather than a balling mill.  The Granite City sinter plant differs
from the Figure 2 flow sheet in that it has none of the following:
                                   14

-------
1.    No balling drum.

2.    No hearth layer.

3.    No hot returns surge bin.

4.    No primary or secondary ore screens.  All ores used for sinter feed
     must be pre-screened.

Table 2 gives the design data for the National Steel sinter plants.

Typical chemical compositions of raw materials used in the National
Steel sinter plants are given in Table 3.  However, the analyses may
vary significantly for such iron-bearing waste materials as blast
furnace flue dust, sludge and BOP dust.  Individual ores may also vary
significantly in composition but less so than the waste materials.  In
general, chemical uniformity is improved with beneficiation of the ores.
Fluxstone and mill scale are generally the most chemically uniform
materials in the sinter mix.  Coke breeze chemistry is dependent upon
the composition of the coals and the coal mix employed at the coke
plant.  Feed coal and coke plant practice affect coke breeze composi-
tion.  Good sinter strand operation requires control of the carbon fuel.
Therefore, the carbon content in the coke breeze, flue dust and sludge
can significantly influence the sintering process.

The average composition of the sinter mix used at Great Lakes in 1972
and the first six months of 1973 and at Weirton No. 2 Strand in 1973 and
1974, is given in Table 4.  The primary difference between 1972 and
1973 at Great Lakes  is the increased fluxstone usage required to obtain
the desired increase in sinter basicity.  This, in turn, has decreased
the proportion of ore and mill scale in the sinter mix.  The Great Lakes
sinter plant commenced operations in 1958 and since then the sinter
mixes have changed in the same manner as indicated in Table 1.  The
                                   15

-------
           Table 2.  NATIONAL STEEL SINTER PLANT DESIGN DATA
          Design
Weirton No. 1
1)  Built and designed by

2)  Active grate area

                 length

                 width


3)  No. of windboxes

4)  Speed range


5)  No. of pallets

6)  Size of pallets


7)  Height of sideboards


8)  No. of grate bars/pallet

9)  Analysis of grate bars
10) 'Ignition furnace
          type fuel
          volume fuel
11) Tempering hood
12) I.D. fans
    (a) No./Volume
    (b) Temperature
Koppers, 1955

     77.3 m2
   (832 ft2)
     31.7 m
   (104 ft)
      2.4 m
     (8 ft)

     13

      0.01-0.06 m/s
     (2-12 fpm)

    103

      0.81 m x 2.4 m
    (32 in x 8 ft)

      0.36 m
    (14 in.)

    124

     27-30 Cr
      1-1/2 - 2 Ni

Arched hood
Coke oven gas
    580 kj
   (550 Btu)
      0.275 in /s
 (35,000 ft3/hr)

      6.1 m
    (20 ft)
   1/99.12 m/s
(210,000 cfm)

    149°C
   (300°F)
                                   16

-------
Table 2.  (continued)
tfeirton No. 2
Koppers, 1958
163.9 m2
(1764 ft2)
44.8 m
(147 ft)
3.7 m
(12 ft)
14
0.025-0.076 m/s
(5-15 fpm)
110
1.07 m x 3.7 m
(42 in x 12 ft)
0.46 m
(18 in)
162
27-30 Cr
1-1/2 - 2 Ni
Arched hood
Coke oven gas
580 kj
(550 Btu)
0.488 in /s
(62,000 ft3/hr)
8.5 m
(28 ft)
2/132.16 m3/s
280,000 cfm) ea
177°C
^350°F)
Great Lakes
Koppers, 1958
222.6 m2
(2396 ft2)
60.8 m
(199 ft 6 in)
3.7 m
(12 ft)
19
0.025-0.102 m/s
(5-20 fpm)
138
1.07 m x 3.7 m
(42 in x 12 ft)
0.46 m
(18 in)
162
27-30 Cr
1-1/2 - 2 Ni
(2) flat roof
Coke oven gas
580 kj
(550 Btu)
1.49 in /s
(190,000 ft3/hr)
None

2/162.37 m3/s
(344,000 cfm) ea
177°C
(350°F)
Granite City
McKee, 1959
95.1 m2
(1024 ft2)
39.0 m
(128 ft)
2.4 m
(8 ft)
16
0.02-0.07 m/s
(3.3-13.2 fpm)
95


0.36 m
(14 in)

27-30 Cr
1-1/2 - 2 Ni
Arched hood
Coke oven gas
580 kj
(550 Btu)


None

1/132.16 m3/s
(280,000 cfm)
149°C
(300°F)
               17

-------
    Table 2.  NATIONAL STEEL SINTER PLANT DESIGN DATA   (continued)
          Design
Weirton No. 1
     (c) Vacuum


     (d) Speed

     (e) Motor


13) Sinter breaker

14) Cooler

    (a) Length


    (b) Width


    (c) Speed range


    (d) Cooler fans

        No./Volume


        Pressure


        Temperature

15) Hot screens

        No./Size

        Deck

16) Cold screens

        Size


        Deck
    762 mm we
    (30 in)

    712 rpm

   1492 kw
  (2000 hp)

Yes

Straightline

     45.7 m
   (150 ft)

      1.5 m
     (5 ft)
      0.01-0.06 m/s
     (2-12 fpm)
   3/38.9 m3/s
 (82,500 cfm) ea

    203 mm we
      (8 in)

Ambient

Stationary grizzly



SAE 4130 (Mod)

W. S. Tyler

F800  - 1.5 m x 3.0 m
      (5 ft x 10 ft)

Rod deck
                                   18

-------
Table 2.  (continued)
Weirton No. 2
1016 mm we
(40 in)
712 rpm
1865 kw
(2500 hp)
Yes
Straightline
45.7 m
(150 ft)
3.0 m
(10 ft)
0.025-0.076 m/s
(5-15 fpm)
2/120.36 m3/s
(255,000 cfm) ea
152 mm we
(6 in)
Ambient
H-R
2/1.5 m x 6.1 m
(5 ft x 20 ft)
SAE 4130 (Mod)
W. S. Tyler
F900 - 1.8 m x 3.7 m
(6 ft x 12 ft)
Cast manganese
Great Lakes
1016 mm we
(40 in)
900 rpm
3357 kw
(4500 hp)
Yes
Straightline
54.4 m
(178 ft 6 in)
3.0 m
(10 ft)
0.025-0.076 m/s
(5-15 fpm)
3/100.1 m3/s
(212,000 cfm) ea
152 mm we
(6 in)
Ambient
H-R
2/1.5 m x 6.1 m
(5 ft x 20 ft)
HC 250
W. S. Tyler
F900 - 1.8 m x 3.7 m
(6 ft x 12 ft)
HC 250
Granite City
762 mm we
(30 in)
900 rpm
1492 kw
(2000 hp)
Yes
Circular
14.6 m dia.
(48 ft)
-
0.03-0.097 m/s
(6-19 fpm)
3/23.6 m3/s
(50,000 cfm) ea
178 mm we
(7 in)
Ambient
H-R
1/1.5 m x 6.9 m
(5 ft x 22 ft 6 in)
USS T-l
W. S. Tyler
1.8 m x 3.7 m
(6 ft x 12 ft)
Rod deck
          19

-------
                         Table 3   CHEMICAL COMPOSITIONS OF NATIONAL STEEL RAW MATERIALS
                                                 (dry basis - %)
Material
Ore A
Ore B
Ore C
Ore D
Fluxstone A
Fluxstone B
Fluxstone C
Fluxstone D
Flue dust A
Flue dust B
Sludge A
Sludge B
Mill scale A
Mill scale B
Coke breeze A
Coke breeze B
BOP dust A
Constituent
Iron
57.71
59.37
47.81
61.01
0.42
0.45
0.45
0.11
40.06
47.77
42.55
42.11
72.90
72.46
4.40
2.99
54.50
Si02
9.55
7.30
17.87
11.29
0.19
1.11
1.38
1.28
6.10
4.55
6.78
7.86
1.43
0.42
3.97
5.01
2.35
Al?0^
0.72
1.56
1.11
0.57
0.31
1.42
1.27
0.18
1.42
1.66
1.23
2.03
0.69
0.18
1.95
2.23
0.10
Cao
0.10
0.03
0.56
0.10
30.32
51.61
45.24
30.16
4.39
4.06
3.87
3.21
0.17
0.65
4.65
0.06
8.00
MgO
0.18
0.04
0.17
0.05
22.26
1.31
7.83
21.09
0.80
2.48
1.95
2.25
0.16
0.43
0.44
0.47
1.70
Mn
0.76
0.57
4.91
0.01
—
-
-
0.60
0.46
0.56
0.41
0.73
-
0.010
-
1.20
Phos
0.049
0.097
0.056
0.010
—
-
-
0.102
0.072
0.136
0.041
0.096
-
0.010
-
0.130
Sulfur
0.005
0.008
0.008
0.015
0.061
0.098
0.032
0.016
0.27
0.31
0.36
0.45
0.038
0.031
0.63
0.92
0.050
Free
Carbon
-
-
-
-
-
-
-
26.55
17.40
18.89
19.40
-
-
71.0
81.2
0.60
NJ
O
      Note:  The values shown are after completion of sintering process & do not reflect moisture,
             oxygen, total carbon, hydrocarbons & trace elements.

-------
Table 4.  SINTER MIXES - YEARLY AVERAGE
              (weight %)
Constituent
Ore
Mill scale
Flue dust
Sludge
Fluxstone
Coke breeze
Sinter basicity
Great Lakes
1972
55.3
10.9
2.2
1.4
24.4
5.8
1.96
1973
54.0
10.7
2.7
0
26.5
6.1
2.06
Weirton
No. 2 Strand
1973
59.50
3.53
1.02
1.40
28.45
6.10
2.25
1974
65.16
3.84
0.16
1.54
22.80
6.50
1.73
                   21

-------
increase  in mill  scale usage  shown  in Table 1 is due to increased steel-
making capacity and  improved  mill scale recovery.  Mill scale is seldom
purchased from outside sources at Great Lakes.  Increased sinter basi-
city has  increased fluxstone  consumption, while improved blast furnace
burdens have reduced the quantity of flue dust and sludge which must be
recycled.  BOP dust  is not presently consumed.

The primary difference between Weirton No. 2 Strand operations for
1973 and  1974 is  the reduced  fluxstone consumption, resulting in lower
sinter basicity.  This is a result  of materials handling limitations and
not a desire to operate at low basicity rates.  The amount of fluxstone
that can  be introduced is limited and 1974 reflects a two plant (Strand
No. 1 and No. 2)  operation versus 1973's single plant (Strand No. 2)
operation.
FUTURE PRACTICES AFFECTING SINTER PLANT EMISSIONS

There are at least four trends in current operating practices that could
alter sintering process emissions.  The trend toward higher sinter
basicity will affect both sinter strand operation and sinter quality.
Limited experience and laboratory tests indicate that sinter strength
increases at the 3.0 sinter basicity envisioned for future sinter plant
operation.  This would result in a decrease in blast-furnace flue dust
and possibly sludge which are recycled to the sintering process.
Limited experience also indicates a more stable sinter strand operation
at the 3.0 basicity level, which should reduce emissions.  While there
may be a slight reduction in hot and/or cold returns generation, it is
doubtful whether this would significantly influence strand operation.
The net effect of higher basicity sinter should be a reduction in
emissions, although the particulate matter will probably be higher in
basic content.
                                   22

-------
A second trend which will influence future sinter plant emissions is
the increased use of in-plant iron-bearing waste materials.  The varia-
tion in the chemical composition of these materials will make control of
sinter chemistry more difficult.  More important, from an emissions
standpoint, is the size consist of these materials.  Since most of these
waste materials will be the byproducts of other pollution control
facilities, they will be fine in size, particularly with respect to the
proportion of material finer than 100 mesh.  Unless properly combined
into the sinter mix, the fine fractions will reduce bed permeability and
make process control more difficult.  The net effect of increased fine
materials usage is the potential for increased particulates in the
waste gas if proper operating conditions are not achieved.  This in-
cludes uniform distribution throughout the mix to prevent concentrated
areas of poor sintering characteristics and adequate micro-balling of
the mix to achieve good bed permeability.

The third trend influencing future sinter plant practice is directly
related to the aforementioned problem of increased fine particles and
involves preconditioning of fine waste materials prior to use in the
sinter mix.  This is already practiced in some foreign countries,
notably Japan, where BOP dust is micro-pelletized to achieve suitable
handling characteristics.  Another method of conditioning is premixing
of all waste materials prior to addition to the sinter mix.  By using a
separate mixing circuit, improved proportioning of these materials is
often achieved.  Micro-pelletization may be enhanced with the appro-
priate equipment and mixtures of waste materials can be handled with
less tendency to become airborne.  The mixture will be more uniformly
dispersed throughout the total sinter mix by subsequent mixing facili-
ties.  The net effect is to improve sinter plant operation, reduce the
tendency for in-plant airborne dusting and minimize emissions.

A fourth factor which could significantly affect future sinter plant
operation and emissions is the process of waste gas recirculation.
                                   23

-------
Batch laboratory tests simulating waste gas recirculation have indicated
that sinter quality can deteriorate if the oxygen in the waste gas
recirculated to the sintering process is less than some minimum value.
This minimum oxygen value appears related to the raw materials mixture
being processed and possibly to the specific process operating condi-
tions.  Whether this minimum value is reached depends on the specific
sinter plant and mode of waste gas recirculation employed.  Limited
application of waste gas recirculation to continuous commercial and
pilot sintering facilities indicates a reduction in particulate and
condensable organic emissions.  It is certain that the final level of
emissions that is achieved will be partially dependent on the stability
of the sinter strand operation.
                                   24

-------
                               SECTION V
                         BASELINE MEASUREMENTS
INTRODUCTION

This section presents a compilation of field testing data and related
sinter plant production information for an existing sintering facility
selected to develop the design for a gas recirculation system.  The
primary field testing for this project was conducted at Great Lakes
Steel's No. 2 Sinter Plant.  This production facility is located on Zug
Island in the city of River Rouge, Michigan.  Zug Island is situated
approximately 4-1/2 miles southwest of the main business district of the
city of Detroit.

Field sampling was conducted under various operating conditions at three
locations in the plant.  Windbox gases were sampled at the main stack,
as were gases generated at the sinter breaker and hot screen areas.  As
mentioned in Section III, this project was transferred from the Great
Lakes Steel to the Weirton Steel Division for completion.  Field test
data obtained by the Weirton Steel Division prior to the transfer are
presented in Appendix A.  These data are qualified because of the dif-
ferent sampling techniques used.  However, the same fundamental para-
meters (hydrocarbons, particulate, and oxygen content) necessary to
evaluate the merits of gas recirculation, as well as other required
system design data, were obtained.
                                   25

-------
TESTING PROCEDURE

These tests were conducted on the main exhaust stack and on breechings
to another stack which serviced in-plant clean-up.  The main stack
samples represented combustion gases generated directly from the sinter-
ing process.  Emissions tests were also conducted at the machine dis-
charge area, particularly at the sinter breaker and hot screens, to
determine if these gases could be used to enrich the oxygen content of
the windbox recirculated gas, should that become necessary to prevent
starving of the combustion process because of too lean a recycled gas.

Tests were conducted on various sinter mixes at different production
rates to define the parameters affecting quality of the generated gases.
Gas flowrates and temperatures were monitored throughout the testing
period.  Fan amperages and speeds were monitored to maintain steady
state operation of the exhaust systems under various production condi-
tions.  Gas composition and particulate loading including condensables
were determined as a result of this field testing program.  Figure 3 is
a plan view of the No. 2 Sinter Plant showing the field sampling loca-
tions.
Gas Flowrate Determinations

Pitot tube traverses were' conducted at each pertinent sampling site by
dividing the stack or breeching into equal areas.  The mid-points of
these areas were measured with an "S" type pitot tube and an inclined
manometer in accordance with procedures in the American Conference of
Governmental Industrial Hygienists Industrial Ventilation manual.  Gas
velocities were monitored during the sampling intervals using pitot tube
measurements.  The sampling rate was then adjusted, when necessary, to
assure isokinetic sampling.
                                   26

-------
                                                       MULTIPLE
                     •SOUTH WINDMAIN   rGOOSENECK   \  CYCLONE
                                        DOWNCOMERS  \ PRECLEANER
                       EXHAUST
                        STACK
                     | SINTER MACHINE
                         MOVEMENT j
                              FOUR SAMPLE PORTS
                                                                                FAN
                          f#3 FAN
                           )
                           LOW ENERGY
                         WET SCRUBBERS
  HOT SCREENS™"^ ^     [TYPICAL)
SAMPLE LOCATION-H^S-SINTER BREAKER
                /   SAMPLING LOCATION
              ^-EXHAUST STACK
                                                         NOTE:
CYCLONE
MAIN EXHAUST
   STACK
                                                               NO.
                  & NO. M- FANS SERVICE
                    HOT SCREENS
                         MAIN EXHAUST
                          FAN &  MOTOR
                            (TYPICAL)
             No.2 & NO.3  FANS SERVICE
                SINTER BREAKER  AREA
                Figure 3.  Plan view of field sampling  locations — Great Lakes

-------
Miscellaneous Determinations

Gas  temperatures  in  the main  stack  and ductwork were recorded period-
ically during each sampling interval.  Gas  temperatures and pressures,
from gages  located on  the dry gas meters and vacuum pumps, were also
recorded during the  sampling  period.  These data were then used to
determine dust loading values.  Gas temperatures were further monitored
by personnel periodically gathering gas samples.
Particulates and Condensables Determinations

The sampling train, shown in Figure 4, was used for collecting partic-
ulates and inorganic and organic condensables.  The fiberglass filter,
shown in the sampling train, removed the particulate emissions during
testing.  The quantity of particulate on the filter and the flow data
collected during testing were used as the basis for all particulate
emission calculations.

The first two impingers in the sampling train, each containing distilled
water, removed the organic and inorganic condensables during testing.
The condensable concentrations were then separated into organic and
inorganic components by determining the quantity soluble in petroleum
ether.  The organic and inorganic condensables collected in the im-
pingers and the flow data collected during testing were used as the
basis for all condensable emission calculations.
SO  Determinations
  A.
Sulfur oxides were collected by the sampling train shown in Figure 5.
The gaseous sulfur compounds, consisting primarily of sulfur trioxide
                                   28

-------
                                                             TEMP. GAGE
  V
      PROBE
 IMPINGERS
 CONTAINING
 DISTILLED
   WATER
     PI TOT TUBE
(T
                                                    VELOCITY  REGULATING
                                                    ORIFICE	
                  FIBERGLASS FILTER
                        MOISTURE TRAP
                    -INCLINED
                   'MANOMETER
VACUUM
 PUMP
 GAS
METER
                         -ATMOSPHERE
                          DISCHARGE
MANOMETER
                                                                                      PYROMETER
              -THERMOCOUPLE
  VELOCITY  DETERMINATION
                                                           TEMPERATURE DETERMINATION
                    Figure 1.  Sampling train for participate determination

-------
and sulfur dioxide, were collected separately, using isopropyl alcohol
and alkaline hydrogen peroxide.  A filter in the sampling train removed
the filterable particulates.  The first impinger, containing isopropyl
alcohol, collected the sulfur trioxide component from the gases.  The
gases were then scrubbed through two Greenberg-Smith series connected
impingers containing 0.1 N NaOH and 5% hydrogen peroxide.  The gas
stream was then metered according to the attached arrangement.

All the impinger samples were returned to the laboratory and analyzed
using barium chloride.  The barium sulfate precipitates were weighed and
appropriate blanks were run for both the isopropyl alcohol and alkaline
peroxide solutions.
Oxides of Nitrogen Determinations

Round bottomed glass flasks were used to collect samples of the exhaust
gas.  These flasks, containing concentrated sulfuric acid and hydrogen
peroxide, were first evacuated of air in a control room situated near
the testing sites.  The method for evacuating these flasks is shown in
Figure 6.

The evacuated flasks were then connected to the sampling train, also
shown in Figure 6.  Samples of the gas were drawn through the train for
a time sufficient to flush the lines completely of air and to fill them
with exhaust gas.  The vacuum pump was then shut down and the evacuated
flash exposed to the stack gases by opening the flask stop cock.  The
gases were then collected in the initially evacuated flask.  The stop
cock was then closed, the opening sealed, and the entire flask sent to
the laboratory for analysis.  The samples were analyzed for total oxides
of nitrogen, using phenol-disulfonic acid.  Standard curves were pre-
pared for calibration, using a known quantity of sodium nitrate.
                                   30

-------
   -PITOT TUBE
              o-.
 NCLINED
MANOMETER
 VELOCITY DETERMINATION
                                                                 PYROMETER
                                       TEMPERATURE DETERMINATION
ISOPROPYL
 ALCOHOL
                FIBERGLASS FILTER
                                                        ATMOSPHERE DISCHARGE

                                                             TEMP. GAGE


                                               VELOCITY REGULATING ORIFICE
ALKALINE H202
                MOISTURE TRAP
                                                          VACUUM
                                                           PUMP
                                                                       MANOMETER
                       Figure 5.  Sampling train for SOL determination
                                                       "

-------
         STOPCOCK
                                       VALVE
^V-VACUUM
     GAGE
                 EVACUATED FLASK
                                                  VACUUM PUMP
CO
                       METHOD OF PREPARATION
                        FOR  EVACUATED  FLASKS
                                PROBE
                                                          FIBERGLASS FILTER
                                                  CORDENSATE
                                                     TRAP
                                                                                            PUMP
                                                                             ^-EVACUATED
                                                                                 FLASK
                       Figure 6.  Sampling system for oxides of  nitrogen determination

-------
Gas Composition Determinations

Gas samples were obtained periodically throughout a given sampling day.
Gas temperatures were also taken to monitor the gas exhaust system.  The
samples were taken by placing a stainless steel probe within the stack
or ductwork and connecting it to a Pyrex gas collecting bottle.  The
other side of the bottle was connected to a vacuum device to purge the
system of air.  Exhaust gas filled the gas collecting bottle.  Stop
cocks located at each end of the bottle were closed and the ends sealed.

The gas samples were then taken to the chemical laboratory for the
analysis of hydrogen, nitrogen, carbon monoxide, carbon dioxide, and
oxygen (by difference), using a Perkin-Elmer Gas Chromatograph, Model
990, Hot Wire Detector.  The chromatograph was calibrated using a pre-
mixed gas of similar composition to those gases being analyzed.
TESTING DISCUSSION
General

Field sampling and testing was conducted at Great Lakes Steel's No. 2
Sinter Plant facility in October, 1973.  This was done to gather addi-
tional information about important operating parameters needed to
properly design a gas recirculation system.  Field testing, conducted
under various operating conditions, yielded information on gas composi-
tion, dust loading, and temperature variations.  These field tests
have helped in identifying and quantifying the main exhaust stack emis-
sions, including sintering process combustion gases, and the sinter
breaker and hot screen discharge area emissions.
                                   33

-------
Information presented in this field sampling report includes the fol-
lowing :

     A measure of materials comprising the sinter feed.

     System operational data for control of the process.

     An analysis of gaseous emissions, including gaseous pollutants and
     those which affect sinter plant operation.

     Particulate loading concentrations and chemical analyses of col-
     lected dust, including a summary of testing results.

Discussion follows on each of the above items to improve understanding
the sintering process and its related gaseous emissions.  Projections
can then be made of foreseeable trends that might cause deviation from
current operating practice and might alter the emissions generated by
the sintering process.


Plant Operation and System Control

Field sampling was conducted during three weeks of sintering.  Each
week a separate production rate and sinter product basicity rating was
selected to evaluate the system generated dust loadings under various
operating conditions.

Table 5 presents plant production data taken during the field sampling
periods.  Although field sampling generally was conducted during the day
turns, additional production data for the other shifts and total daily
production figures are also presented to indicate the consistency of
sinter production.  The No. 2 Sinter Plant, where tests were conducted,
                                   34

-------
generally decreases sinter production as the sinter basicity increases.
Throughout the weeks of testing, three separate production goals were
selected with their respective sinter basicity in order to provide
adequate fluxing product for the four blast furnaces located at Great
Lakes Steel.  The daily production goal for the first week of testing
was set at 5200 mtpd at 2.0 basicity.  The actual production data sup-
ports this goal.  Each successive week, for two weeks, a lesser sinter
production rate was selected.  The sinter basicity was increased to 2.5
in the second week and then finally to 3.0 basicity in the final week.
Table 5 also includes information about the sinter feed mix selected to
develop the desired sinter production basicity.

The day after each week's testing period was selected by operating
personnel as a down-turn period during which maintenance, general repair
and clean-up of the plant took place.  We observed that maintenance and
clean-up generally increased as the sinter product basicity increased.
This corresponds with the increasing dust content of the in-plant air as
the production basicity increased.
                                    35

-------
Table 5.  PLANT PRODUCTION DATA
DESCRIPTION
SINTER PLANT PRODUCTION
Turn No. 1 11-7 Shift
mtpd (tpd)
Turn No. 2 7-3 Shift
mtpd (tpd)
Turn No. 3 3-11 Shift
mtpd (tpd)
Total
mtpd (tpd)
AVERAGE SINTER BASICITY
Turn No. 1 11-7 Shift
Turn No. 2 7-3 Shift
Turn No. 3 3-11 Shift
Average
SINTER MIX - % BASIS
Hanna ore
Labrador ore
Moose mountain ore
Lauretta ore
Total ore mix
Scale
Flue dust
Sludge (filter cake)
Coke breeze
Limestone
Dolomite
TOTAL RAW MIX
Cold sinter returns
Hot sinter returns
TOTAL MIX
1ST WEEK TESTING
10-16-73
1589
(1750)
1816
(2000)
1816
(2000)
5221
(5750)
1.99
2.00
2.15
2.05
17.0
18.5
-
8.5
44.0
5.4
1.5
-
4.7
9.7
9.7
75.0
17.2
7.8
100.0
10-17-73
1816
(2000)
1816
(2000)
1816
(2000)
5448
(6000)
2.04
1.89
2.00
1.98
17.0
18.5
-
8.4
43.9
5.4
1.4
-
5.1
9.7
9.7
75.2
17.4
7.4
100.0
10-18-73
1816
(2000)
1531
(1687)
1589
(1750)
4936
(5437)
2.19
2.15
2.00
2.11
13.4
19.7
-
8.9
42.0
5.4
1.6
-
5.0
10.2
10.2
74.4
17.4
8.2
100.0
TEST PERIOD
AVG.
1740
(1917)
1721
(1896)
1740
(1917)
5201
(5730)
2.07
2.01
2.05
2.05
15.8
18.9
-
8.6
43.3
5.4
1.5
-
4.9
9.9
9.9
74.9
17.3
7.8
100.0
              36

-------
Table 5.  (continued)
2ND WEEK TESTING
10-22-73
1692
(1864)
1692
(1864)
1692
(1864)
5076
(5592)
2.34
2.53
2.54
2.47
12.8
18.4
8.5
39.7
5.4
1.5
5.0
9.3
13.6
74.5
17.8
7.7
100.0
10-23-73
1587
(1748)
1469
(1618)
1473
(1623)
4529
(4989)
2.35
2.18
2.37
2.30
11.9
17.8
8.8
38.5
5.4
1.5
5.0
9.2
13.6
73.2
18.5
8.3
100.0
10-25-73
1
1620
(1784)
1639
(1806)
1322
(1456)
4581
(5046)
2.38
2.01
2.46
2.28
12.4
18.2
9.1
39.7
5.7
1.1
4.8
9.3
11.7
!
72.3
19.1
8.6
100.0
TEST PERIOD
AVG.
1633
(1799)
1600
(1763)
1496
(1648)
4729
(5210)
2.36
2.24
2.46
2.35
12.4
18.1
8.8
39.3
5.5
1.4
4.9
9.3
12.9
73.3
18.5
8.2
100.0
3RD WEEK TESTING
10-29-73
1242
(1368)
1334
(1469)
1511
(1664)
4087
(4501)
2.55
2.96
3.34
2.95
8.5
15.2
9.9
33.6
6.1
-
5.6
8.5
16.7
70.5
20.7
8.8
100.0
10-31-73
1511
(1664)
1039
(1144)
897
(988)
3447
(3796)
2.91
2.87
2.83
2.87
10.8
14.9
9.2
34.9
6.1
1.4
5.4
8.3
15.9
72.0
19.5
8.5
100.0
TEST PERIOD
AVG.
1377
(1516)
1187
(1307)
1204
(1326)
3768
(4149)
2.73
2.92
3.09
2.91
9.6
15.1
9.6
34.3
6.1
0.7
5.5
8.4
16.3
71.3
20.1
8.6
100.0
           37

-------
38

-------
Plant Operation and System Control (continued)

To monitor the system, several operating parameters were selected by the
teams conducting the field testing.  Table 6 presents daily averages of
those monitoring parameters.  For example, observation of the exhaust
gas temperatures from the main exhaust stack, sinter breaker area and
hot screens area indicates a general consistency of these parameters
over the entire three-week testing period.  On the other hand, the
sinter breaker and hot screen exhaust gases fluctuated consistently
around the daily values due to the variation in the water supplied to
low-energy wet scrubbers ahead of the selected sampling locations.

Fan speed, motor speed and motor current are also shown in Table 6 for
the entire discharge area in-plant gas cleaning system.  Only the
northwest half of this system, Fan Systems No. 3 and No. 4, were selec-
ted for actual field testing, owing to the limited manpower available
for field and analytical work.  The other two fan systems were monitored
to assure to field personnel that samples obtained from each half of the
system were consistent with those from the other half.  Observation of
the presented data shows this consistency.  Fluctuations in the observed
data resulted from manual injection of water to the scrubbers and from
operating conditions beyond the control of the field testing teams.
                                   39

-------
Table 6.  SYSTEM OPERATIONAL DATA
DESCRIPTION
MAIN EXHAUST STACK
Avg gas temp °C
(°F)
SINTER BREAKER AREA
No. 2 fan system
Fan speed rpm
Motor speed rpm
Avg motor current
amps
No. 3 fan system
Avg gas temp °C
(°F)
Fan speed rpm
Motor speed rpm
Avg motor current
amps
HOT SCREENS AREA
No. 1 fan system
Fan speed rpm
Motor speed rpm
Avg motor current
amps
No. 4 fan system
Avg gas temp °C
(°F)
Fan speed rpm
Motor speed rpm
Avg motor current
amps
1ST WEEK TESTING
10-15-73


1610
1195


52
(126)
1622
1195


1610
1195


64
(148)
1633
1195

10-16-73
72
(162)



83

26
(80)


65



103

51
(123)


100
10-17-73
83
(181)





30
(86)








47
(118)



10-18-73
81
(179)

1622
1195
98

32
(90)
1600
1195
70

1589
1195
90

53
(127)


90
TEST PERIOD
AVG.
79
(174)

1617
1195
91

35
(96)
1610
1195
68

1600
1195
97

54
(129)
1633
1195
95
                40

-------
Table 6.  (continued)
2ND WEEK TESTING
10-22-73
74
(166)


90
32
(90)


67


70
50
(122)


93
10-23-73

1656
1195
100

1633
1195
70
1633
1195
70

1661
1195
100
10-25-73
88
(190)



36
(96)






38
(100)



TEST PERIOD
AVG.
81
(178)
1656
1195
95
34
(93)
1633
1195
69
1633
1195
70
44
(111)
1661
1195
97
3RD WEEK TESTING
10-29-73
81
(178)


80
32
(90)


70


73
36
(97)


72
10-31-73

1600
1195
•73
33
(91)
1645
1195
63
1667
1195
68
27
(81)
1645
1195
60
TEST PERIOD
AVG.
81
(178)
1600
1195
73
33
(91)
1645
1195
63
1667
1195
71
32
(89)
1645
1195
66
          41

-------
42

-------
Chemical Composition of Exhaust Gases

Tables 7, 8 and 9 present a detailed analysis of the chemical composi-
tion of the gases from the main exhaust stack, sinter breaker, and hot
screens areas, respectively.  The main exhaust gases are of paramount
importance since they are the primary source for recirculation of gases
back to the sinter machine.  Generally, three field samples were taken
of the main stack gases daily.  The oxygen content of these gases
averaged 16% by volume, with a variation of - 2%.  Further observation
of Table 7 data does not reveal a definite pattern in the oxygen content
as compared to sinter production variations.  In fact, selection of any
other gaseous composition indicates a relative uniformity independent of
sinter production, as far as the main exhaust stack gases are concerned.
This conclusion is based only on the variations of sinter production
selected for the field testing periods.

Tables 8 and 9 indicate the same consistency for gases generated at the
discharge area as that observed for main stack gases; that is, the
consistency apparently is independent of production rate and sinter
product basicity.  The oxygen content of either gas stream from the
discharge area is generally 20% with a variation of - 1%.  Review of the
composition of the gases from the discharge area indicates that rela-
tively little combustion occurs as the sinter is discharged from the
pallets, broken into large pieces, and primarily classified at the hot
screens area.  Other than the presence of a small quantity of oxides of
sulfur and nitrogen and the hot and dusty condition of the gas, these
gases are quite similar to atmospheric air.  On a gas composition basis
only, these discharge area gases may be considered for usage in enrich-
ing the primary recirculation gases, should the latter stream become
"too-lean" in oxygen content to adequately support combustion in the
'sinter burden.
                                   43

-------
Table 7.  MAIN EXHAUST STACK GAS COMPOSITION DATA
DESCRIPTION
HYDROGEN - % BY VOLUME
Test 1
Test 2
Test 3
Average
NITROGEN - % BY VOLUME
Test 1
Test 2
Test 3
Average
CARBON MONOXIDE - % BY VOLUME
Test 1
Test 2
Test 3
Average
CARBON DIOXIDE - % BY VOLUME
Test 1
Test 2
Test 3
Average
OXYGEN - % BY VOLUME (BY DIFF)j
Test 1
Test 2
Test 3
Average
SULFUR TRIOXIDE - PPM BASIS
Test 1
Test 2
Test 3
Average
SULFUR DIOXIDE - PPM BASIS
Test 1
Test 2
Test 3
Average
OXIDES OF NITROGEN -
PPM AS N02
Test 1
Test 2
Test 3
Average
1ST WEEK TESTING
10-16-73
1.02
1.12
1.12
1.08
76.82
76.82
77.66
77.10
0.43
0.25
0.47
0.38
4.86
3.97
5.21
4.68
16.87
17.84
15.54
16.76
11.0
11.0
0.61
0.61
40.4
40.4
10-17-73
0.89
1.17
1.03
78.49
80.16
79.33
0.62
0.62
0.62
5.92
5.59
5.76
14.08
12.46
13.26
0.89
0.89
1.34
1.34
22.4
22.4
10-18-73
1.07
1.06
1.15
1.09
78.49
77.85
77.85
78.06
0.52
0.39
0.38
0.43
5.23
4.99
4.48
4.90
14.69
15.71
16.14
15.52
6.30
6.40
6.35
0.34
0.30
0.27
0.30
75.6
85.7
42.6
68.0
TEST PERIOD
AVG.
0.99
1.12
1.14
1.07
77.93
78.28
77.76
78.16
0.52
0.42
0.43
0.48
5.34
4.85
4.85
5.11
15.22
15.33
15.82
15.18
6.06
6.40
6.23
0.76
0.30
0.27
0.44
46.1
85.7
42.6
43.6
                        44

-------
Table 7.  (continued)
2ND WEEK TESTING

10-22-73
1.04
1.15
1.15
1.11
74.39
77.85
77.85
76.10
0.40
0.36
0.21
0.32
5.25
4.99
3.04
4.43
18.72
15.65
17.75
17.44
1.03
2.98
1.27
1.76
0.37
0.25
0.42
0.35
58.4
46.4
49.7
51.5

10-25-73
1.13
1.13

1.13
77.85
77.85

77.85
0.14
0.49

0.32
1.73
5.25

3.49
19.15
15.28

17.21
0.27
1.16
0.21
0.55
0.49
0.31
0.23
0.34
12.8
66.6
16.9
32.1
TEST PERIOD
AVG.
1.09
1.14
1.15
1.12
76.12
77.85
77.85
77.28
0.27
0.43
0.21
0.32
3.49
5.12
3.04
3.96
19.04
15.47
17.75
17.33
0.65
2.07
0.74
1.15
0.43
0.28
0.33
0.35
35.6
56.5
33.3
41.8
3RD WEEK TESTING

10-29-73
1.18
1.14
1.11
1.14
76.12
76.99
76.99
76.70
0.46
0.49
0.33
0.43
6.08
6.02
3.78
5.29
16.16
15.36
17.79
16.44
0.24
3.66
3.36
2.42
0.19
0.46
0.38
0.34
69.9
58.9
38.0
55.6

10-31-73
1.13
1.13
1.11
1.12
77.88
77.00
77.88
77.59
0.22
0.30
0.32
0.28
3.78
4.13
5.38
4.43
16.99
17.44
15.31
16.58
0.24


0.24
0.19


0.19
58.6
50.0
40.9
49.8
TEST PERIOD
AVG.
1.16
1.14
1.11
1.13
77.00
77.00
77.44
77.15
0.34
0.40
0.33
0.36
4.93
5.08
4.58
4.86
16.57
16.38
16.54
16.50
0.24
3.66
3.36
2.42
0.19
0.46
0.38
0.34
64.3
54.5
39.5
52.7
          45

-------
Table 8.  SINTER BREAKER AREA GAS COMPOSITION DATA
DESCRIPTION
HYDROGEN - % BY VOLUME
Test 1
Test 2
Test 3
Average
NITROGEN - % BY VOLUME
Test 1
Test 2
Test 3
Average
CARBON MONOXIDE - % BY VOLUME
Test 1
Test 2
Test 3
Average
CARBON DIOXIDE - % BY VOLUME
Test 1
Test 2
Test 3
Average
OXYGEN - % BY VOLUME (BY DIFF)
Test 1
Test 2
Test 3
Average
SULFUR TRIOXIDE - PPM BASIS
Test 1
Test 2
Test 3
Average
SULFUR DIOXIDE - PPM BASIS
Test 1
Test 2
Test 3
Average
OXIDES OF NITROGEN -
PPM AS NO?
Test 1
Test 2
Test 3
Average
1ST WEEK TESTING
10-16-73
1.10
1.12
1.12
1.11
78.49
78.49
78.49
78.49
0.01
0.01
0.01
0.01
0.13
0.11
0.15
0.13
20.27
20.27
20.23
20.26
0.10
0.10
0.23
0.23
6.4
6.4
10-17-73
1.05
1.17
1.11
78.49
80.16
79.33
0.03
0.01
0.02
0.12
0.19
0.16
20.31
18.47
19.38
0.71
0.71
0.26
0.26
2.6
2.6
10-18-73
0.61
1.09
1.15
0.95
79.33
78.72
78.72
78.92
0.02
0.01
0.01
0.01
0.25
0.15
0.23
0.21
19.79
20.03
19.89
19.91
0.19
0.35
0.17
0.24
0.30
0.30
0.41
0.34
4.0
4.0
4.0
TEST PERIOD
AVG.
0.92
1.13
1.14
1.06
78.77
79.12
78.61
78.91
0.02
0.01
0.01
0.01
0.17
0.15
0.19
0.17
20.12
19.59
20.05
19.85
0.33
0.35
0.17
0.28
0.26
0.30
0.41
0.32
4.3
4.0
4.2
                        46

-------
Table 8.  (continued)
2ND WEEK TESTING

10-22-73
1.11
1.15
1.15
1.14
77.85
77.85
77.85
77.85
0.01
0.01
0.01
0.01
0.14
0.16
0.14
0.15
20.89
20.83
20.85
20.85
0.22
0.29
0.24
0.25
0.25
0.25
0.28
0.26
4.9
6.9
3.7
5.2

10-25-73
1.13
1.13

1.13
76.99
77.85

77.42
0.01
0.01

0.01
0.17
0.08

0.13
21.70
20.93

21.31
0.33


0.33
0.52


0.52
1.3
2.6

2.0
TEST PERIOD
AVG.
1.12
1.14
1.15
1.14
77.42
77.85
77.85
77.64
0.01
0.01
0.01
0.01
0.16
0.12
0.14
0.14
21.29
20.88
20.85
21.07
0.28
0.29
0.24
0.27
0.39
0.25
0.28
0.31
3.1
4.8
3.7
3.9
3RD WEEK TESTING

10-29-73
1.18
1.11
1.11
1.13
77.85
76.99
77.85
77.56
0.01
0.27
0.01
0.10
0.22
0.12
0.21
0.18
20.74
21.51
20.82
21.03
0.14
0.14
0.35
0.21
0.20
0.19
0.29
0.23
4.0
2.6
4.0
3.5

10-31-73
1.13
1.13
1.13
1.13
78.76
78.76
78.76
78.76
0.01
0.01
0.01
0.01
0.05
0.14
0.12
0.10
20.05
19.96
19.98
20.00
0.19
0.16

0.18
0.39
0.29

0.34
1.0
1.0
2.0
1.3
TEST PERIOD
AVG.
1.16
1.12
1.12
1.13
78.31
77.88
78.31
78.16
0.01
0.14
0.01
0.06
0.14
0.13
0.17
0.14
20.38
20.73
20.39
20.51
0.17
0.15
0.35
0.22
0.30
0.24
0.29
0.28
2.5
1.8
3.0
2.4
          47

-------
Table 9.  HOT SCREENS AREA GAS COMPOSITION DATA
DESCRIPTION
HYDROGEN - % BY VOLUME
Test 1
Test 2
Test 3
Average
NITROGEN - % BY VOLUME
Test 1
Test 2
Test 3
Average
CARBON MONOXIDE - % BY VOLUME
Test 1
Test 2
Test 3
Average
CARBON DIOXIDE - % BY VOLUME
Test 1
Test 2
Test 3
Average
OXYGEN - % BY VOLUME (BY DIFF)
Test 1
Test 2
Test 3
Average
SULFUR TRIOXIDE - PPM BASIS
Test 1
Test 2
Test 3
Average
SULFUR DIOXIDE - PPM BASIS
Test 1
Test 2
Test 3
Average
OXIDES OF NITROGEN -
PPM AS NO?
Test 1
Test 2
Test 3
Average
1ST WEEK TESTING
10-16-73
1.10
1.12
1.15
1.12
78.49
78.49
78.49
78.49
0.01
0.04
0.01
0.02
0.23
0.18
0.32
0.24
20.17
20.17
20.03
20.13
0.80
0.80
0.37
0.37
1.3
1.3
10-17-73
1.00
1.11
1.06
78.49
79.33
78.91
0.01
0.02
0.02
0.34
0.27
0.31
20.16
19.27
19.70
1.07
1.07
0.30
0.30
5.8
5.8
10-18-73
1.23
1.09
1.12
1.15
78.49
78.72
78.72
78.64
0.01
0.01
0.02
0.01
0.20
0.17
0.32
0.23
20.07
20.01
19.82
19.97
0.24
0.24
0.68
0.68
5.3
5.3
TEST PERIOD
AVG.
1.11
1.11
1.14
1.12
78.49
78.85
78.61
78.65
0.01
0.02
0.02
0.02
0.26
0.21
0.32
0.26
20.13
19.81
19.91
19.95
0.70
0.70
0.45
0.45
4.1
4.1
                       48

-------
Table 9.  (continued)
2ND WEEK TESTING

10-22-73

1.14
1.14
1.15
1.14
77.85
78.72
77.85
78.14
0.01
0.01
0.01
0.01
0.42
0.05
0.09
0.19
20.58
20.08

20.90
20.52
0.46
0.39
0.94
0.60
1.08
0.64
0.81
0.84
8.4
5.1
7.9
7.1

10-25-73

1.13
1.16

1.15
77.85
77.85

77.85
0.01
0.01

0.01
0.30
0.11

0.21
20.71
20.87


20.78
0.15


0.15
0.33


0.33
8.3
2.2 ,
5.3
5.3
TEST PERIOD
AVG.

1.14
1.15
1.15
1.15
77.85
78.29
77.85
78.00
0.01
0.01
3RD WEEK TESTING

10-29-73

1.18
1.14
1.11
1.14
78.72
77.85
77.85
78.14
0.01
0.02
0.01 0.01
0.01
0.36
0.08
0.09
0.18
20.64
20.47

20.90
20.66
0.31
0.39
0.94
0.55
0.71
0.64
0.81
0.72
8.4
3.7
6.6
6.2
0.02
0.19
0.39
0.29
0.29
19.90
20.60

10-31-73

1.16
1.18
1.13
1.16
78.76
78.76
78.76
78.76
0.03
0.02
0.01
0.02
0.46
0.52
0.11
0.36
19.59
19.52

20.74 i 19.99
20.41
0.20
0.51
0.22
0.31
0.20
0.52
0.32
0.35
6.5
4.3
5.8
19.70
0.34


0.34
0.32


0.32
5.1
2.4
1.2
TEST PERIOD
AVG.

1.17
1.16
1.12
1.15
78.74
78.31
78.31
78.45
0.02
0.02
0.01
0.02
0.33
0.46
0.20
0.33
19.74
20.05

20.36
20.05
0.27
0.51
0.22
0.33
0.26
0.52
0.32
0.37
5.8
3.4
3.5
5.5 2.9 4.2
          49

-------
Emissions Data

Daily average emissions concentrations in the gas streams from the main
exhaust stack, sinter breaker, and hot screens areas are presented in
Table 10.  The data are classified as particulate, inorganic condensables
and organic condensables.

The particulate concentrations in the main exhaust stack gas stream
generally increased as the sinter product basicity increased.  However,
this conclusion is based only on the weekly average values developed.
Observation of the daily data reveals that values for the particulate
concentration are very erratic.  Since the testing and analytical pro-
cedures were consistent throughout the testing period, and field person-
nel were essentially unchanged, the wide variations in particulate values
must have resulted from sinter production variations.  But shift and
daily production figures indicated an overall sinter product uniformity;
therefore, small changes in the raw mix moisture adjustment, and of Btu
variations in the furnace gas used, must have been reflected in the
samples collected.  The increase of particulate in the main exhaust
stack gases as sinter basicity increased was also confirmed by field
testing personnel, as was the general increase in required plant clean-
up after each production campaign.

Particulate concentrations in the sinter breaker area, calculated from
the field sampling values, reveal no consistent pattern or correlation
with sinter production rates.  Observations by field test personnel
indicate that dust generation and thermal movement of air increased as
sinter basicity increased.  The data, however, indicate that gas flow-
rate and the cleaning of the gas by cyclones and gas scrubbers remained
essentially the same.
                                   50

-------
The data for the hot screens area generally indicates an increase in
particulate and inorganic condensables and a decrease in organic con-
densables with increasing basicity.

Particulate in the sinter breaker and hot screens discharge gases is so
substantial that these gases should not be considered for oxygen enrich-
ment unless more effective gas cleaning is achieved.  Sinter production
upsets could cause the recycled gas to become pressurized in the hood
over the sinter machine and discharge dirty gases into the plant atmo-
sphere.

Table 11 shows the analysis of the emissions collected in the field
sampling trains.  The data indicates a definite increase in the calcium,
magnesium, and carbonate content of the dust from all three sampling
areas, as the sinter product basicity increases.  The iron in the dust,
on the other hand, decreased.  These analytical evaluations are con-
sistent with the type of sinter being produced.

Tables 12 and 13 summarize the previous seven tables.  In addition, gas
flowrates are presented for future use in the development of a gas
recirculation system.
                                   51

-------
                   Table 10.  EMISSIONS DATA
DESCRIPTION
MAIN EXHAUST STACK
Particulate
mg/m^
(gr/scf)
Inorganic condensables
mg/m^
(gr/scf)
Organic condensables
mg/m^
(gr/scf)
SINTER BREAKER AREA
Particulate
rng/m^
(gr/scf)
Inorganic condensables
mg/m^
(gr/scf)
Organic condensables
rng/m^
(gr/scf)
HOT SCREEN AREA
Particulate
mg/m^
(gr/scf)
Inorganic condensables
mg/m^
(gr/scf)
Organic condensables
mg/rn-^
(gr/scf)
1ST WEEK TESTING
10-16-73
44.3
(0.019)
23.1
(0.010)
18.9
(0.008)
164.7
(0.072)
53.8
(0.023)
38.6
(0.017)
124.1
(0.054)
57.3
(0.025)
11.0
(0.005)
10-17-73
139.8
(0.061)
1.7
(0.0007)
0.4
(0.0002)
74.6
(0.032)
11.1
(0.005)
1.6
(0.001)
76.5
(0.033)
16.4
(0.007)
0.5
(0.0002)
10-18-73
179.1
(0.078)
131.2
(0.057)
6.2
(0.003)
159.0
(0.069)
39.0
(0.017)
5.8
(0.003)
214.4
(0.093)
134.5
(0.058)
14.6
(0.006)
AVERAGE
121.1
(0.053)
52.0
(0.022)
8.5
(0.004)
132.8
(0.058)
34.6
(0.015)
15.3
(0.007)
138.3
(0.060)
69.4
(0.030)
8.7
(0.004)
rag/up = milligrams of particulate per cubic meter of gas at 21.1°C
(70°F) and 1.0 atmosphere pressure
                               52

-------
Table 10.  (continued)
2ND WEEK TESTING
10-22-73
165.4
(0.072)
67.3
(0.029)
8.7
(0.004)
67.3
(0.029)
46.5
(0.020)
5.7
(0.002)
251.1
(0.109)
100.9
(0.044)
6.3
(0.003)
10-25-73
159.0
(0.069)
100.2
(0.043)
9.6
(0.004)
150.6
(0.066)
67.7
(0.029)
7.4
(0.003)
80.9
(0.035)
8.25
(0.004)
7.9
(0.003)
AVERAGE
162.2
(0.071)
83.8
(0.036)
9.1
(0.004)
109.0
(0.048)
57.1
(0.025)
6.5
(0.003)
166.0
(0.072)
91.7
(0.040)
7.1
(0.003)
3RD WEEK TESTING
10-29-73
155.7
(0.068)
62.8
(0.027)
4.4
(0.002)
109.2
(0.048)
21.1
(0.009)
1.9
(0.001)
2178.5
(0.952)
90.9
(0.039)
1.5
(0.001)
10-31-73
204.0
(0.089)
213.3
(0.093)
7.2
(0.003)
52.0
(0.023)
64.4
(0.028)
2.6
(0.001)
1083.7
(0.473)
519.0
(0.227)
2.7
(0.001)
AVERAGE
179.9
(0.078)
138.0
(0.060)
5.8
(0.003)
80.6
(0.035)
42.8
(0.018)
2.2
(0.001)
1631.1
(0.713)
305.0
(0.133)
2.1
(0.001)
           53

-------
               Table 11.  EMISSIONS CHEMICAL COMPOSITION
DESCRIPTION

MAIN EXHAUST STACK
Wt. % - Fe (a)
Wt. % - Ca
Wt. % - Mg
Wt. % - C03
Wt. % - Organic (b)
Wt. % - Combustible (c)
Wt. % - Undetermined (d)
SINTER BREAKER AREA
Wt. % - Fe
Wt. % - Ca
Wt. % - Mg
Wt. % - C03
Wt. % - Organic
Wt. % - Combustible
Wt. % - Undetermined
HOT SCREENS AREA
Wt. % - Fe
Wt. % - Ca
Wt. % - Mg
Wt. % - C03
Wt. % - Organic
Wt. % - Combustible
Wt. % - Undetermined
1ST WEEK TESTING

10-16-73


8.4
4.3
1.3
1.1
0.1
2.5
82.3
24.5
11.8
2.9
4.2
1.4
8.2
47.0

10-17-73
13.6
8.6
2.0
4.1
1.9
15.8
54.0
24.7
12.3
3.4
4.0
0.3
7.4
47.9
21.0
11.5
2.8
7.5
1.2
7.7
48.3

10-18-73
17.9
11.9
1.6
7.2
3.2
13.4
44.8
21.9
13.0
3.2
9.2
2.6
9.8
40.3
25.6
9.6
2.3
12.5
2.1
8.0
39.9
TEST PERIOD
AVERAGE
15.9
10.2
1.8
5.7
2.6
14.6
49.4
18.3
9.9
2.6
4.8
1.0
6.6
56.8
23.6
10.9
2.7
8.1
1.6
8.0
45.1
(a)  Values presented are average values of samples taken in any
    sampling day.
(b)  Represents material that was soluble in petroleum ether.
(c)  Represents material lost from sample at 450°C.
(d)  Value of difference between given chemical composition and 100%.
                                   54

-------
Table 11.  (continued)
2ND WEEK TESTING

10-22-73
14.0
13.6
4.1
11.3
2.3
13.2
41.5
24.1
18.4
6.4
7.7
4.2
12.1
27.1
19.5
13.4
5.0
9.8
1.8
10.5
40.0

10-25-73
13^0
10.4
2.2
2.1
5.4
14.1
52.8
18.2
11.2
2.7
5.3
4.9
11.3
46.4
19.2
14.5
2.2
8.8
6.6
10.7
38.0
TEST PERIOD
AVERAGE
13.5
12.0
3.2
6.1
3.8
13.7
47.1
21.2
14.8
4.6
6.5
4.5
11.7
36.7
19.3
14.0
3.6
9.3
4.2
10.6
39.0
3RD WEEK TESTING

10-29-73
9.5
11.8
5.0
6.1
3.6
14.1
49.9
19.8
18.2
7.8
7.4
1.2
9.2
36.4
17.0
7.2
3.0
18.6
0.1
6.3
47.8

10-31-73
14.0
16.2
6.2
14.5
1.9
14.9
32.3
22.1
16.0
7.1
6.7
3.7
12.0
32.4
19.2
9.7
4.2
20.6
0.4
6.5
39.4
TEST PERIOD
AVERAGE
11.8
14.0
5.6
10.3
2.7
14.5
41.1
20.9
17.1
7.5
7.1
2.4
10.6
34.4
18.1
8.4
3.6
19.6
0.3
6.4
43.6
           55

-------
                     Table 12.  FIELD TEST SUMMARY
DESCRIPTION
MAIN EXHAUST STACK

1st week testing (b)
2nd week testing (b)
3rd week testing (b)
SINTER BREAKER AREA

1st week testing
2nd week testing
3rd week testing
HOT SCREEN AREA

1st week testing
2nd week testing
3rd week testing
PLANT
PRODUCTION
mtpd (tpd)

5201
(5730)
4729
(5210)
3768
(4149) .

5201
(5730)
4729
(5210)
3768
(4149)

5201
(5730)
4729
(5210)
3768
(4149)
PRODUCT
BASICITY

2.05
2.35
2.91

2.05
2.35
2.91

2.05
2.35
2.91
GAS
FLOWRATE
m3/s (acfm)
335.6 (a)
(710,955)



29.0 (a)
(61,350)



53.0 (a)
(113,000)



GAS
TEMPERATURE
c<> (FO)
43 (a)
(110)
79
(174)
81
(178)
81
(178)
34 (a)
(94)
35
(96)
34
(93)
33
(91)
39 (a)
(102)
54
(129)
44
(HI)
32
(89)
(a)  Actual gas flowrates and related temperatures were determined
    immediately preceding actual field test periods.
(b)  Related values in table presented as weekly averages.
                                   56

-------
Table 12.  (continued)
GAS COMPOSITION
H2 %
1.07
1.12
1.13
1.06
1.14
1.13
1.12
1.15
1.15
N2 %
78.16
77.28
77.15
78.91
77.64
78.16
78.65
78.00
78.45
CO %
0.48
0.32
0.36
0.01
0.01
0.06
0.02
0.01
0.02
C02 %
5.11
3.96
4.86
0.17
0.14
0.14
0.26
0.18
0.33
02 %
15.18
17.33
16.50
19.85
21.07
20.51
19.95
20.66
20.05
S03 PPM
6.23
1.15
2.42
0.28
0.27
0.22
0.70
0.55
0.33
S02 PPM
0.44
0.35
0.34
0.32
0.31
0.28
0.45
0.72
0.37
NOx PPM
43.6
41.8
52.7
4.2
3.9
2.4
4.1
6.2
4.2
           57

-------
Table 13.  FIELD TEST SUMMARY



DESCRIPTION
MAIN EXHAUST STACK
1st week testing

2nd week testing

3rd week testing

SINTER BREAKER AREA
1st week testing

2nd week testing

3rd week testing

HOT SCREEN AREA
1st week testing

2nd week testing

3rd week testing


PARTICULATE
mg/m3
(gr/scf)

121.1
(0.053)
162.2
(0.071)
179.9
(0.078)

132.8
(0.058)
109.0
(0.047)
80.6
(0.035)

138.3
(0.060)
166.0
(0.072)
1631.1
(0.713)
INORGANIC
CONDENSABLES
o
mg/m
(gr/scf)

52.0
(0.023)
83.8
(0.036)
138.0
(0.060)

34.6
(0.015)
57.1
(0.025)
42.8
(0.018)

69.4
(0.030)
91.7
(0.040)
305.0
(0.133)
ORGANIC
CONDENSABLES
mg/m3
(gr/scf)

8.5
(0.004)
9.1
(0.004)
5.8
(0.003)

15.3
(0.007)
6.5
(0.003)
2.2
(0,001)

8.7
(0.004)
7.1
(0.003)
2(.l
(0.001)
              58

-------
                              SECTION VI
                            PROCESS DESIGN
PROCESS DESIGN STUDY


Introduction

Contained herein is the design study for a Waste Gas Recycle System on
No. 2 Sinter Strand for Weirton Steel Division, National Steel Corpora-
tion, Weirton, West Virginia.  The system offers the following potential
advantages:

     Reduces the quantity of gases to be cleaned.

     Reduces the capital investment for final gas cleaning equipment.

     Reduces the total emission to the atmosphere for a given dust
     concentration.

     Reduces the hydrocarbon content in exhaust gases.

     Increases flexibility of operation.

These potential advantages justified the design of a waste gas recircu-
lation system.
                                    59

-------
Design Considerations

Synthesis of the waste gas recycle system required the evaluation of two
limiting parameters.  These parameters were  (1) the gas oxygen content
which affects the combustion process and sinter quality, and (2) the
minimizing of downtime during the retrofit of the Sinter Plant so that
sinter would always be available to the blast furnaces.  Figure 1 in
Section III shows the general arrangement of the recirculation system
installed at the Weirton Steel Division No. 2  Sinter Strand.  Table 14
is a summary of the waste gas process calculations for this system as a
function of recycle percentage.  Based on these results, it was con-
cluded that a 39% recycle should be the maximum design recirculation
rate because of the rapidly decreasing oxygen content in the recircu-
lated gas and the large rate of increase in fan horsepower with
increasing recycle percentage.
System Description

Two waste gas fans, identical in performance and construction, operate
in parallel.  They are sized to discharge to the main exhaust stack all
the waste gas'from the sintering strand or to recirculate to the sinter-
ing machine hood up to 39% of the waste gas.  Four duct valves, two for
flow control and two for shutoff, control the waste gas recirculated to
the sinter machine.  The control system permits a once through operation
or recirculation rates ranging from 0 to 50%.  Provision is made for
additional cleaning of the unrecirculated waste gas prior to discharge
to the atmosphere.  Specifications used as the basis for equipment
selection are as follows:
                                   60

-------
Once Through Operation - each fan:
Standard gas flow
Actual gas flow
Temperature
Density
Fan static pressure
Fan motor power
88.0 Nm /s
159.8 m3/s
139°C
0.743 kg/nf
1118 mm we
2615 kw
(200,000 scfm)
(340,000 acfm)
(282°F)
(0.0464  Ibs/cf)
(44.0 in)
(3505 bhp)
39% Waste Gas Recycle to Machine Hood - each fan:
Standard gas flow
Actual gas flow
Temperature
Density
Fan static pressure
Fan motor power
88.0 Nm /s
184.7 m3/s
194°C
0.646 kg/m2
1290 mm we
3328 kw
     (200,000 scfm)
     (393,000 acfm)
     (382°F)
     (0.0403 Ibs/cf)
     (50.8 in)
     (4327 bhp)
Recycle Hood -
Standard volume
Actual volume
Temperature
Oxygen
68.6 Nm /s           (156,000 scfm)
136.3 m3/s           (290,000 acfm)
219°C                (427°F)
17.56% above sinter  bed
Future Gas Cleaning System -  inlet  conditions:
 Standard volume
 Actual volume
 Temperature
 Pressure
 Moisture
 Dust
 Hydrocarbons
107.4 Nm /s
212.9 m3/s
219°C
51 mm we positive
74.42 g/Nm3
0.923 g/Nm3
0.369 g/Nm3
     (244,000 scfm)
     (453,000 acfm)
     (427°F)
     (2 in)
     (30.25 grains/scf)
     (0.375 grains/scf)
     (0.150 grains/scf)
                                    61

-------
                Table 14.  SUMMARY OF CALCULATED DATA*
% of Waste Gas Recycled
Gas flow each fan (dry)

Nm3/s
(scfm)
Waste gas temperature at fan °C

Pressure drop across 356 mm
(14 in) sinter bed

Pressure drop in
existing cyclones
Pressure drop in
ductwork to fan
Fan inlet pressure

Gas volume at fan inlet

Gas density

Pressure drop in fan
ductwork to hood
Fan static pressure

Fan motor power

Volume recycled (dry)

Volume recycled to hood

Oxygen above sinter bed
Gas flow to stack

Saturated gas flow to stack

Saturation gas temperature

<°F)

mm we
(in we)
mm we
(in we)
mm we
(in we)
mm we
(in we)
m3/s
(acfm)
kg/m3
(Ibs/cu ft)
mm we
(in we)
mm we
(in we)
kw
(bhp)
Nm /s
(scfm)
m3/s
(acfm)
%
m /s
(acfm)
m /s
(acfm)
°C
(°F)
0
88.0
(200,000)
139
(282)

762
(30)
203
(8.0)
102
(4.0)
-1067
(-42.0)
159.8
(340,000)
0.743
(0.0464)
50.8
(2.0)
1118
(44.0)
2615
(3505)
0
(0)
0
(0)
21.00
284.4
(605,000)
236.9
(504,000)
50
(122)
10
88.0
(200,000)
150
(302)

785
(30.9)
208
(8.2)
109
(4.3)
-1102
(-43.4)
165.4
(352,000)
0.721
(0.0450)
53.3
(2.1)
1156
(45.5)
2745
(3680)
17.6
(40,000)
31.0
(66,000)
20.35
279.7
(595,000)
216.2
(460,000)
52
(125)
* see Appendix B for calculations used to compile this table.
                                   62

-------
Table 14.  (continued)
20
88.0
(200,000)
163
(325)
800
(31.5)
213
(8.4)
117
(4.6)
-1130
(-44.5)
171.6
(365,000)
0.697
(0.0435)
58.4
(2.3)
1189
(46.8)
2880
(3880)
35.2
(80,000)
63.9
(136,000)
19.66
256.2
(545,000)
194.6
(414,000)
53
(127)
30
88.0
(200,000)
178
(352)
818
(32.2)
224
(8.8)
127
(5.0)
-1168
(-46.0)
178.6
(380,000)
0.674
(0.0421)
63.5
(2.5)
1232
(48.5)
3051
(4090)
52.8
(120,000)
99.6
(212,000)
18.70
233.6
(497,000)
173.4
(369,000)
55
(131)
39
88.0
(200,000)
194
(382)
856
(33.7)
229
(9.0)
135
(5.3)
-1219
(-48.0)
184.7
(393,000)
0.646
(0.0403)
71.1
(2.8)
1290
(50.8)
3228
(4327)
68.6
(156,000)
136.88
(290,000)
17.56
212.9
(453,000)
155.1
(330,000)
57
(134)
50
88.0
(200,000)
226
(438)
927
(36.5)
246
(9.7)
145
(5.7)
-1318
(-51.9)
205.4
(437,000)
0.593
(0.0370)
81.3
(3.2)
1400
(55.1)
3849
(5160)
88.0
(200,000)
189.4
(403,000)
15.65
189.4
(403,000)
133.0
(283,000)
60
(140)
            63

-------
System Features - This waste gas recycle system offers the following
advantageous features:

     System can be retrofitted to the sinter plant as a peripheral
     facility with minimum downtime for a final tie-in.

     Highest ratio of recirculation of waste gases to machine hood while
     maintaining an adequate amount of oxygen for the sintering process.

     Conservation of energy required for sintering process by recircula-
     ting hot gases.

     Flexibility of operation in handling sintering machine waste gases.

     Flexibility for meeting existing or future air pollution regula-
     tions.

     Smaller inventory of spare parts needed because both waste gas fans
     and drives are identical.

     Low initial capital investment.
Discussion - Fan selection for this system has been based on maximum
wind flow volumes, temperatures and pressures as determined from test
data.

                                                                1  3
For this report, total process wind volume is defined as 187.44 Nm /s
                                    o
(426,000 scfm), containing 49.2 g/Nm  (20 grains per scf) of moisture or
176.0 Nm3/s (400,000 scfm) of dry gas.
Table 14 shows calculated waste gas fan and future gas cleaning data for
0 to 50% recirculation.
                                   64

-------
Appendix B contains the process design calculations used in the design
of the gas recirculation system.
Future Discharge Waste Gas Cleaning System

Several types of future gas cleaning systems have been considered for
the treatment before discharge to atmosphere of 61% of waste gas.

Three of the most promising systems are wet scrubbers, wet electrostatic
precipitators, and gravel bed filters.
Wet Scrubber - A wet scrubber system would require an additional fan
operating in series with the waste gas fan, wet scrubber and moisture
eliminator.  This system would also require scrubber water recirculating
pumps, pumps to transfer slurry to an existing thickener, a water treat-
ment system, and controls.
Scrubber fan -

Standard gas flow        107.4 Nm /s          (244,000 scfm)
Actual gas  flow          212.9 m3/s           (453,000 acfm)
Gas  temperature          219°C                (427°F)
Gas  density             0.716 kg/m3          (0.0447 Ibs/cf)
Fan  static  pressure      1143 mm we           (45 in)
Fan  motor power          3320 kw              (4450 bhp)
                                   65

-------
Scrubber inlet conditions -
Gas flow                 202.1 m3/s           (430,000 acfm)
Pressure                 1194 mm positive     (47 in)
Temperature              241°C                (465°F)
Moisture                 74.42 g/Nm3          (30.25 grains/scf)
Dust                     0.923 g/Nm3          (0.375 grains/scf)
Hydrocarbons             0.369 g/Nm           (0.150 grains/scf)
Scrubber outlet conditions -
                                3
Gas flow                 157.5 m /s saturated      (335,000 acfin)
Pressure                 51 mm we positive         (2  in)
Temperature              58°C saturated          !  (136°F)
                                   3
Dust and hydrocarbons    0.049 g/Nm                (0.02 grains/scf)
                               3
Water evaporated         65.4 m /h                 (288 gpm)
Moisture eliminator - Electrostatic type, expected to be highly ef-
ficient in reducing the rain-out problem.
Water recirculating pumps -

Flow                     681 m3/h             (3000 gpm)
Total dynamic head       22.9 m               (75 ft)
Motor power              75 kw                (100 bhp)
Slurry transfer  (blow-down) pumps -

Flow                     136.2 m3/h           (600 gpm)
Total dynamic head       22.9 m               (75 ft)
Motor power              15 kw                (20 bhp)
                                   66

-------
Slurry load to thickener -

Flow                     136.2 m3/h          (600 gpm)
Solids                   8.6 mtpd            (9.5 short tons/day)
Advantages of wet scrubber -

Relatively low initial capital investment.

Low maintenance cost.

Proven in sintering plant applications.


Disadvantages of wet scrubber -

Requires gas pressure booster fan.

Low hydrocarbon removal efficiency.

High power consumption.

Limitation in size which could require two scrubber-separator sets to
handle gas flow.

Requires expensive recirculating water and blow-down water treatment
systems.
                                   67

-------
Wet Electrostatic Precipitator -
Precipitator inlet conditions -
Standard gas flow
Actual gas flow
Pressure
Temperature
Moisture
Dust
Hydrocarbons
107.4 NnT/s
212.9 m3/s
51 mm we
219°C
74.42 g/Nm3
0.923 g/Nm3
0.369 g/Nm3
(244000 scfm)
(453000 acfm)
(2 in)
(427°F)
(30.25 grains/scf)
(0.375 grains/scf)
(0.150 grains/scf)
Precipitator outlet conditions
Actual gas flow
Pressure
Temperature
Dust and hydrocarbons
Water evaporated
156.0 in /s
13 mm we positive
57°C
0.049 g/Nm3
61.3 m3/h
(332000 acfm)
(0.5 in)
(134.5°F)
(0.02  grains/scf)
(270 gpm)
Moisture eliminator - Electrostatic type, expected to be highly ef-
ficient in reducing rain-out problem.
Water recirculating pumps -
Flow
Total dynamic head
Motor power
351.9 m /h
47.3 m
78 kw
(1550 gpm)
(155 ft)
(105 bhp)
                                   68

-------
Slurry transfer (blow-down) pumps -

Flow                     136.2 m3/h          (600 gpm)
Total dynamic head       22.9 m              (75 ft)
Motor power              15 kw               (20 bhp)
Slurry load to thickener -

Flow                     136.2 m3/h          (600 gpm)
Solids                   8.6 mtpd            (9.5 short tons/day)
Advantages of wet precipitator -

Low pressure drop.  A gas pressure booster fan is not required.

Low fire hazard.

High gas cleaning efficiency.

Low stack rain-out.


Disadvantages of wet precipitator -

Very high initial cost.

High real estate space requirement.

Have not been proved in actual sinter plant application.
                                   69

-------
Gravel Bed Filters  -
Filter  inlet  conditions  -
Standard gas  flow
Actual gas  flow
Pressure
Temperature
Moisture
Dust
Hydrocarbons
107.4 Nm /s
212.9 m3/s
51 mm we
219°C
74.42 g/Nm3
0.923 g/Nm3
0.369 g/Nm3
(244,000 scfm)
(453,000 acfm)
(2 in)
(427°F)
(30.25 grains/scf)
(0.375 grains/scf)
(0.150 grains/scf)
Filter outlet conditions -
Gas flow
Pressure
Temperature
Dust and hydrocarbons
212.9 mJ/s          (453,000 acfm)
203.2 mm we negative     (-8 in)
219°C               (427°F)
0.049 g/Nm~
(0.02 grains/scf)
Filter fan -
Standard gas flow
Actual gas flow
Temperature
Density
Fan static pressure
Fan motor power
107.4 Nm /s
212.9 m3/s
219°C
0.716 kg/m3
254.0 mm we
729 kw
(244,000 scfm)
(453,000 acfm)
(427°F)
(0.0447  Ibs/cf)
(10 in)
(977 bhp)
                                   70

-------
Advantages of gravel bed filter -

Relatively low initial capital investment.

Low maintenance cost.

System is totally dry.  No water treatment necessary.

No stack rain-out.


Disadvantage of gravel bed filter -

Gas pressure booster fan and reverse flow cleaning fan required.

High real estate space requirement.

Haye not been proved in actual sinter plant application.
Equipment Selection Prior to Atmospheric Discharge - Based on pilot
testing and the advantages listed above, a gravel bed filter system has
been selected for full scale evaluation.  This system is sized to handle
approximately 50% of  the waste gas from the sinter strand.  Testing will
be conducted for once-through and for recycle conditions.
                                    71

-------
PROCESS DESCRIPTION

This chapter describes the operation and control of the waste gas re-
circulation system.

Figure 7 is the air and gas flow diagram for waste gas recycle system
showing some of the instrumentation used to control the fans, the hood
valves and the stack valves.

Figure 8 through 11 illustrate the various components included in this
new system.  All have been constructed of carbon steel.

Two exhaust gas fans arranged in parallel provide the induced draft
necessary for processing and dust collecting.

Exhaust gases pass through two parallel hot mains to two banks of
cyclone dust collectors for removal of the larger solid particles.  Each
bank of collectors handles fifty percent of the total machine exhaust
volume.  From the cyclones, the gases flow to a plenum chambet for
distribution to the induced draft fans.  The waste gas fan draws fifty
percent of the gas volume from the plenum chamber and exhausts it to the
stack.  The recycle gas fan draws fifty percent of the total exhaust gas
volume from the plenum chamber, and distributes 39% of the total exhaust
volume to the recycle hood over the machine and the remainder1to the
stack.

The design basis for this recirculation system has been established at a
recycle rate of thirty-nine percent of the waste gas.  However, to allow
for field adjustment and flexibility of operation, the equipment can be
adjusted from zero to fifty percent recirculation.

The recycle gases are returned to the machine in a common header from
which six ducts distribute the gases along the length of the sinter bed.
                                   72

-------
Since the recycle gases provide only thirty-nine percent of the process
air requirement, the remaining sixty-one percent is introduced to the
sinter bed through adjustable openings in the recycle hood.
Control Description

Waste Gas Fan - The output of the waste gas fan, fifty percent of the
total gas flow through the sinter machine, is directed to the waste gas
stack.

The waste gas fan operation can be controlled either manually or auto-
matically.  The manual mode must be used for fan start-up.  The auto-
matic mode is used for normal on line operation.

In the automatic mode, fan volume is controlled by monitoring the motor
load current and regulating the inlet louver dampers accordingly.  The
controller closes the inlet louver dampers when the motor current in-
creases above the normal operating value.

Fan pressure and motor current are continuously recorded.

Visible and audible alarms are provided on both motor and fan bearings
to annunciate abnormal temperatures and vibrations.
Recycle Gas Fan - The output of the recycle gas fan is divided between
the sinter machine hood and the waste gas stack.  Its operation and
control is identical to that of the waste gas fan.
                                    73

-------
WEIRTON STEEL DIVISION SINTER PLANT GAS RECIRCULATION SYSTEM
       STACK
                                                                   39% RECYCLE FLOW
                                                                 73.04 Nm'/s (166000 scfm)
               WASTE GAS FAN
                DOUBLE INLET
              LOUVER DAMPERS
           50% FLOW
           93.72 Nm3/s (213000 scfm)
           184.71 m3/s (393000 acfm)
           194°C, 0.646 kg/m3
           (382°F,.0403lb./ft.3)
           FSP = 1290 mm w.c. (50.8")
     RECYCLE FAN
    DOUBLE INLET
   LOUVER DAMPERS
50% FLOW
93.72 Nm3/s (213000 scfm)
184.71 m3/s (393000 acfm)
194°C, 0.646 kg/m3
<382'F,.0403lb./ft.3)
FSP = 1290 mm w.c. (50.8")
                                Figure 7. Flow diagram
                                       74

-------
 WEIRTON STEEL DIVISION SINTER PLANT GAS RECIRCULATION SYSTEM
     • FROM RECYCLE GAS FAN
                                                                                     I
          Fl  --  AE1 — AT— AY — AR
NORMAL FEED RATE
336 mtph (370tph)
   SINTER MIX
              IGNITION
              FURNACE
               VVvvVVvvvvvvVv
   REPORT FOR
   SINTER MIX
   COMPOSITION
                                                                    WASTE GAS MAINS
                                           SINTERING MACHINE
                                               14 WIND BOXES
                                      (IV? WIND BOXES TO IGNITION FURNACE)
         CYCLONES
                    INSTRUMENTS
	ELECTRICAL SIGNAL LINE         IT.
AE . OXYGEN PROBt.                 I'E •
ARA . OXYGEN CONTENT RECORDER      PIC
AT. OXYGEN CONTENT ANALYZER
   TEMP. CONTROLLER/TRANSMITTER   PI •
AY . OXYGEN CONTENT ANALYZER       CT •
   AMPLIFIER                    HC
CD. CONTROL DRIVE                |p.
Fl . FLOW INDICATOR
IIC. CURRENT CONTROLLER
                           Figure 7. Flow diagram (continued)
CURRENT TRANSMITTER
 PRESSURE SUMMER
. PRESSURE INDICATING
 CONTROLLER
PRESSURE INDICATOR
 PRESSURE TRANSMITTER
. MANUAL CONTROL
CURRENT TO
PNEUMATIC CONVERTER
SOLENOID VALVE
                                         75

-------
The gas recycled to the sinter machine hood is proportioned by posi-
tioning two valves, one in the duct to the hood and the other in the
duct to the stack.
Hood and Stack Valves - Hood and stack valve control circuits are so
arranged that either valve can be selected to provide range control of
the volume and pressure of gas recycled to the sinter machine hood while
the other valve provides trim control.  The selected range valve is
manually positioned and the trim valve is positioned automatically to
maintain the desired hood pressure.  In the automatic mode the control-
ler senses hood pressure, and positions the selected valve in the duct
to control the pressure in the hood.

Two similar valves, one each upstream of the hood and stack valves, are
normally used for shut-off.  They are operated manually.

The hood pressure and the oxygen content of the recycle gas are.contin-
uously recorded.

Visible and audible alarms are provided for annunciating out-of-limits
hood pressure and oxygen content.
                                   76

-------
                                                       RECYCLE HOOD
 RECYCLE GAS
CONTROL HOUSE
                 WASTE GAS
               CONTROL HOUSE
                        Figure 8. General arrangement of system

  WEIRTON STEEL DIVISION SINTER PLANT GAS RECIRCULATION SYSTEM

-------
                     WEIRTON STEEL DIVISION SINTER PLANT GAS RECIRCULATION SYSTEM
oo
             RECYCLE GAS FAN
                                                                        RECYCLE GAS MAIN
                      RECYCLE GAS
                     CONTROL HOUSE
                      WASTE GAS
                    CONTROL HOUSE
                                                                    SINTER MACHINE
        DOWNCOMERS


-WASTE GAS MAIN


      RECYCLE HOOD
            - WASTE GAS FAN
                                                    Figure 9. Plan

-------
WEIRTON STEEL DIVISION SINTER PLANT GAS RECIRCULATION SYSTEM
                                      STACK
                                               WASTE GAS DUCT
                                                      STACK VALVES
                                                     WASTE GAS
                                                   CONTROL HOUSE
 RECYCLE GAS
CONTROL HOUSE
                            Figure 10. North elevation
                                 79

-------
WEIRTON STEEL DIVISION SINTER PLANT GAS RECIRCULATION SYSTEM
             •*.%'?'-o:?°]-'-'$*&-?o'fftf.Q^o?f4/?&?t':?:'6
                           Figure 11. Cross section thru machine
                                  80

-------
ENVIRONMENTAL POSTURE

The design concept introduced with this system was developed to reduce
the air pollution conditions inherent in the handling of sinter machine
waste gases.  This system is intended as an interim step, to be followed
later by the addition of a gas cleaning system to reduce the waste gas
emissions in compliance with all applicable state and federal environ-
mental codes.  Several gas cleaning systems are under study; these were
discussed briefly earlier in this section.

The conventional system, currently in use throughout the industry and
presently in use at Weirton, discharges all sinter machine waste gases
to atmosphere through a stack.  Particulate discharge is reduced by
passing the gases through multiclone or cyclone dust collectors.

The new system reduces the waste gases discharged to the atmosphere.
Particulate emissions and hydrocarbon emissions are correspondingly
reduced.  The anticipated reduction in emissions for the number 2 sinter
strand at Weirton with waste gas recirculation is thirty percent.
                                    81

-------
COST ESTIMATES

Capital Cost Estimate

The estimated capital cost of the gas recirculation system including
engineering, equipment and installation is:            $4,400,000
Operating Cost Estimate

Estimated annual operating costs for the gas recirculation system are as
follows:

Power (additional for fans and controls, 2984 kw)      $315,000
Maintenance labor                                      $140,000
Maintenance material and spare parts                   $ 50,000
Total annual cost                                      $505,000
                                   82

-------
                              SECTION VII
                    PRELIMINARY TEST PROGRAM DESIGN
INTRODUCTION

The following preliminary test program is intended to serve as a guide
in preparing the work plan and scope of work for any future EPA contract
executed to demonstrate the effectiveness of a windbox gas recirculation
system for the reduction of sinter machine emissions.  The windbox gas
recirculation system should reduce the energy required and volume of gas
to be cleaned.  The gas not recirculated must be cleaned in a separate
facility before it is released to the atmosphere.  The program should,
therefore, include tests of the separate and combined facilities.
Pursuant to this goal, the following four-step program is recommended.
STEP I - PROJECT PREPARATION

Step I should include preparation of a work plan, and the design and
installation of sampling facilities for the recirculation system and the
gas cleaning system.  Six months should be allowed for Step I starting
with the completion of the recirculation and gas cleaning equipment
installation.
                                   83

-------
STEP II - DEBUGGING AND TESTING OF THE WINDBOX GAS RECIRCULATION
          SYSTEM

Step II should allocate three months for debugging and optimization of
the windbox gas recirculation system.  Upon selection of a satisfactory
recirculation rate, emission characterization and system evaluation
tests should be started.  These tests, extending over a period of six
months, should include:

     Determination of sinter feed materials quantities.

     Analysis of the sinter machine gas.  These determinations must be
     made in conformance with EPA methods for particulate sampling as
     stated in the Federal Register, and should include:

          Velocity traverses
          Gas analyses
          Particulate mass loadings
          Moisture determinations

     Each test should be repeated a minimum of three times at the
     selected recirculation rate.  Tests should be repeated periodically
     during the six-month interval as required to establish that condi-
     tions are stable.

     Velocity and temperature monitoring of the waste gas and recircu-
     lated gas to determine the recirculation rate at any desired time.

     Sampling to determine sulfur dioxide concentrations in the effluent
     gases.

     Sampling of condensable hydrocarbons to determine the reduction
     accomplished by windbox gas recirculation.  Areas sampled should
     include:
                                   84

-------
          Raw materials feed
          Sinter product
          Windbox
          Recycle gas
STEP III - DEBUGGING AND TESTING OF THE FINAL AIR POLLUTION
           CONTROL DEVICE

In Step III, three months should be allotted for debugging and optimiza-
tion of the final air pollution control device.  After this period, a
six-month test and evaluation of the air pollution control device should
be undertaken.  This testing should determine the device's efficiency
for removing both particulate and condensable hydrocarbon emissions.
STEP IV  DEBUGGING AND TESTING OF THE COMBINED FACILITY

Step IV follows after the previous steps have established that the waste
gas recirculation and the air pollution control systems have merit as
independent facilities.  Step IV then evaluates the results of operating
both systems simultaneously as if they were a unified pollution control
facility.

Three months should be allotted to step IV testing to determine the
effectiveness of particulate and condensable hydrocarbon removal in the
combined facility.

At the conclusion of these steps a final report should be prepared to
describe the program and document the results of the emissions tests.
                                   85

-------
                             SECTION VIII
                              REFERENCES
1.   McGannon, H. E., Ed., The Making, Shaping and Treating of Steel,
     United States Steel, 8th Edition, 1964, Pages 189-192.

2.   Strassburger, J. H., Ed., "Sintering," Blast Furnace Theory and
     Practice, Volume I, Gordon and Breach Science Publishers, New York,
     1969.

3.   Kinsey, F. W., "Design Features of a Modern Sinter Plant," TMS-
     AIME Ironmaking Proceedings, Volume 29, 1970, Page 98.

4.   AISI Technical Committee on Blast Furnace Practice, Quarterly
     Sinter Plant Data, Second Quarter, 1962.

5.   AISI Technical Committee on Blast Furnace Practice, Operating Data,
     First Quarter, 1973.

6.   Suitlas, J. R., "Emission Characteristics and Pilot Plant Studies
     on a Sintering Plant Windbox Discharge," TMS-AIME Ironmaking
     Proceedings, Volume 30, 1971, Page. 461.
                                   86

-------
                              SECTION IX
                             BIBLIOGRAPHY
The following publications represent a comprehensive bibliography of the
sintering process and associated topics.  Included are publications
relating to the fundamentals of the sintering process, factors influ-
encing the sintering process and its control, chemical and physical
properties of sinter, sinter mineralogy, sinter basicity and its rela-
tionship to the sintering process, sinter properties, and sinter plant
emissions.  The material is organized into four categories, in accor-
dance with the basic theme of the publication:

     Fundamentals of the Sintering Process
     Sinter Chemistry, Mineralogy and Basicity
     Sinter Plant Process Variables, Materials and Control
     Sinter Plant Emissions

All articles are available in English.  In addition, the following
sources offer comprehensive information on the sintering process and/or
extensive bibliographies:

Strassburger, J. H., Ed., "Sintering," Blast Furnace, Theory and
Practice, Volume 1, Gordon and Breach Science Publishers, New York,
1969.

Elliot, G. D. and Bond, J. A., Practical Ironmaking, United Steel
Companies, Ltd., 1959.
                                   87

-------
Knepper, W. A., Ed., Agglomeration, Interscience Publishers, New York,
1962.

Ironmaking in the Blast Furnace, Iron and Steel Institute, London,
Bibliographical Series 23, 1963, Bibliographic Series 23a, 1966.
FUNDAMENTALS OF THE SINTERING PROCESS

Burlingame, R. D., Bitsianes, G., and Joseph, T. L., "Reaction Zones in
the Iron Ore Sintering Process," Proceedings, AIME Blast Furnace, Coke
Oven and Raw Materials Conference, Vol. 15, 1956, pp 216-234.

McBriar, E. M., et al, "The Nature of Ironstone Sinter," Journal, Iron
and Steel Institute, Vol. 177, July, 1954, pp 316-323.

Davies, W. E., "Some Practical Applications of Fundamental Sinter
Research," Canadian Mining and Metallurgical Bulletin, Vol. 53, March,
1960, pp 173-185.

Voice, E. W. and Wild, R., "Importance of Heat Transfer and Combustion
in Sintering," Iron and Coal Trades Review, Vol. 175, October 11, 1957,
pp 841-850.

Voice, E. W. and Wild, R., "How Can Theory Help Us to Make More Sinter,"
Proceedings, AIME Blast Furnace, Coke Oven and Raw Materials Conference,
Vol. 16, 1957, pp 121-146.

Voice, E. W. and Wild, R., "The Influence of Fundamental Factors on the
Sintering Process," Sintering Symposium, Australasian Institute of
Mining and Metallurgy, September, 1958, pp 21-46.
                                   88

-------
Blaskett, D. R., "Heat Flow and Movement of the Combustion Zone in a
Sinter Bed," Sintering Symposium, Australasian Institute of Mining and
Metallurgy, September, 1958, pp 61-70.

Grice, M. A. K. and Davies, W., "Towards Faster Sintering of  Ironstone,"
Journal, Iron and Steel Institute, Vol. 175, 1953, pp 155-160.

Schluter, R. and Bitsianes, G., "The Combustion Zone in the Iron Ore
Sintering Process," Agglomeration, Interscience Publishers, New York,
1962, pp 585-636.

Bhrany, U. W. and Pelezarski,  E. A., "Role of Fuel Reactivity in Sin-
tering," Preprint, 142nd National ACS Meeting, Division of Fuel Chem-
istry, Atlantic City, New Jersey, September 9-14, 1962.

Michael, J., "Combustion of Carbon and Thermal Balance in Sintering,"
Second Symposium on Iron Ore Sintering, Paris, 1957; Iron and Coal
Trades Review, Vol. 175, December 27, 1957, pp 1477-1487.

Dixon, K. G., "Alternative Fuels for Sintering," Journal, Iron and Steel
Institute, Vol. 200,  1962, pp  120-125.

Myron, T. L., Faigen, M. R., and Franklin, R. L., "Fuels for  Sintering,"
Proceedings, AIME Blast Furnace, Coke Oven and Raw Materials  Conference,
Vol.  17, 1958, pp 282-290.

Dixon K. G. and Voice, E. W.,  "Fuel and Energy Required  for Ore Prepara-
tion, " Journal, IJEista1tutie_oJ_J\iels, Vol. 36, 1961, pp 529-534.

Jennings, R. F., "An  Improved  Method of Sintering High-Volatile Iron
Ores," Second Symposium on Iron Ore Sintering, Paris, 1957; Iron and
Coal  Trades Review, Vol. 175,  July 5, 1957, pp 15-19.
                                    89

-------
Ban, T. E., Czako, C. A., Thompson, C. D., and Violetta, D. C., "The
Continuous Sintering Process - Research and Applications," Agglomera-
tion, Interscience Publishers, New York, 1962, pp 511-536.

Voice, E. W. and Wild, R., "A Laboratory Study of the Sintering Pro-
cess," Journal, Iron and Steel Institute, Vol. 183, 1956, pp 404-410.

Sanbongi, K. and Nishida, N., "Fundamental Study of the Sintering of
Iron Ores," Tetsu-to-liagane1 Overseas, Vol. 1, No. 3, December, 1961,
pp 16-24.

Wendeborn, H. B., "Sintering as a Physical Process," Journal, Iron and
Steel Institute, Vol. 175, 1953, pp 280-288.

Davies, W. and Mitchell, D. W., "Development in Sintering Efficiency,"
Proceedings, International Mineral Dressing Congress, Stockholm, 1957,
pp 305-364.

Voice, E. W., Brooks, S. H., and Gledhill, P. K., "The Permeability of
Sinter Beds," Journal, Iron and Steel Institute, Vol. 175, 1953, pp 136-
139.

Robertson, B. L., Haslam, N., and Siddons, R. H., "Appleby-Frodingham
Sinter Plants.  Output and Quality Ratings," Second Symposium on Iron
Ore Sintering, Paris, 1957; Iron and Coal Trades Review, Vol. 176, March
28, 1958, pp 739-750.

Boucraut, M. and Michard, J., "Recent Trends in Sintering of Low-Grade
Self-Fluxing Lorraine Iron Ores," Proceedings, AIME Blast Furnace, Coke
Oven and Raw Materials Conference, Vol. 21, 1962, pp 325-369.

Wild, R. and Dixon, K. G., "Pressure and Water Gradients through a
Sinter Bed," Agglomeration, Interscience Publishers, New York, 1962, pp
565-580.
                                   90

-------
Mitchell, D. W., "Some Aspects of Airflow Through Sinter Beds," Journal,
Iron and Steel Institute, Vol. 198, 1961, pp 358-363.

Callender, W., "Studies in Sintering Permeability and Pellet Strength of
Australian Hematite Ores," Symposium on the Iron and Steel Industry in
India, 1959, p 114.

Ksendzyk, G. V., "Variation of Hydraulic Resistance of Sinter Bed During
Sintering Process," Izvest. Vysshikh Uchebo Zavedenii Chernaya Met.,
Vol. 7, 1958, pp 3-16; Henry Brutcher Translation No. 4632.

Muchi, I. and Higuchi, J., "Theoretical Analysis of Sintering Opera-
tion," Transactions, Iron and Steel Institute of Japan, Vol. 12, 1972,
pp 54-63.

Frolov, Yu A., et al., "Selection of Type of Fuel for Ignition and
Combined Heating of Sintering Mixes," Stal, No. 10, 1970, pp 764-768.
SINTER CHEMISTRY, MINERALOGY AND BASICITY

Coh'en, E., "Radiographic Studies of the Process of Sintering  Iron Ores,"
Journal, Iron and Steel Institute, Vol. 175, 1953, pp 160-166.

Wild, R., "The Chemical Constitution of Sinters," Journal,  Iron and
Steel Institute, Vol. 174, 1953, pp 131-135.

Moleva,  N. G. and Kusakin, P. S.,  "Mineralogical Make-Up of Fluxed
Sinters," Stal, Vol. 17, 1957, pp  1068-1071; Henry Brutcher Translation
No. 4142.

Nekrasor, Z. I., et al, "Special Features of Mineralogical  Composition
and Structure of Fluxed Sinter of  High Iron Content," Stal, No. 12,
1966, pp 951-956.
                                   91

-------
Akhmetov, S. F., et al, "Mineral Composition of Fluxed Sinters," Stal,
No. 6, 1967, pp 455-457.

Bagnall, E. J., et al, "Influence of Feed Size Distribution on Sinter
Microstructures and Properties," BHP Technical Review, Vol. 17 April,
1973, pp 24-29.

Knepper, W. A., Snow R. B., and Johnson, R. T., "Study of the Properties
of Self-Fluxing Sinters," Agglomeration, Interscience Publishers, New
York, 1962, pp 787-804.

Kissin, D. A. and Litvinova, T. I., "Mechanism of Mineral Formation in
Sintering Fluxed Sinter," Stal (in English), No. 5, 1960, pp 318-323.

Kraner, H., "The Mineralogy of Blast Furnace Sinter," Transactions,
AIME, Vol. 196, Technical Publication No. 3673B, 1953, pp 1114-1117.

Bogan, L. C. and Worner, H. K., "Structures and Bonding Mechanisms in
Sinters Made from Fine-Grained Australian Hematites," Agglomeration,
Interscience Publishers, New York, 1962, pp 901-925.

Doi, Y. and Kasai, K., "The Making of Self-Fluxing Sinter and the Blast
Furnace Practice with its 100 Per Cent Sinter Burden," Proceedings,
AIME Blast Furnace, Coke Oven and Raw Materials Conference," Vol. 18,
195?, pp 182-205.

Nyquist, 0., "Effects of Lime on the Sintering of Pure Hematite and
Magnetite Concentrates," Agglomeration, Interscience Publishers, New
York, 1962, pp 809-858.

Watanabe, S., "Fundamental Studies of Self-Fluxing Sinter," Agglomera-
tion, Interscience Publishers, New York, 1962, pp 865-894.
                                   92

-------
Namyatov, G. N., et al, "Removal of Sulphide and Sulfate Sulfur in the
Sintering of Iron Ores," Stal, No. 11, 1965, pp 864-866.

Gregory, J. A. and Wolski, S., "Experimental Assessment of Factors
Controlling the Production of High Basicity Sinter," BHP Technical
Bulletin, Vol. 9, April, 1965, pp 31-35.

Mazanek, E. and Jasienska, S., "Properties of Self-Fluxing (Iron Ore)
Sinters of Basicity 1.0-3.5," Journal, Iron and Steel Institute, Vol.
206, 1968, pp 1104-1109.

Fredock, M. P., et al, "Dicalcium Ferrite  (C_F) Sinter - Its Develop-
ment, Production and Use," TMS-AIME Ironmaking Proceedings, Vol. 27,
1968, pp 144-148.
 SINTER PLANT PROCESS AND  CONTROL

 Voice, E. W., Brooks,  S.  H., Davies, W., and Robertson, R. L.,  "Factors
 Controlling the  Rate of Sinter Production," Journal,  Iron and Steel
 Institute, Vol.  175, 1953, pp 97-152.

 Machkovskii, V.  A., et al, "Use of  Radioactive  Isotopes to Investigate
 the  Degree of Mixing of the Mix," Stal, No. 6,  1968,  pp 465-467.

 Limons,  R. A. and  Kraner, H. M., "An Evaluation of  the Properties  of
 Dolomites Affecting Self-Fluxing Sinter Rates," Agglomeration,  Inter-
 science  Publishers, New York, 1962, pp 117-143.

 Brandes, G. and  Rausch, H., "Mixing and Conditioning  of Sinter  Plant
 Feed," Proceedings, AIME  Blast Furnace, Coke Oven and Raw Materials
 Conference, Vol. 18, 1959, pp 232-249.
                                    93

-------
Stirling, H. T., "Advances in Balling and Pelletizing," Agglomeration,
Interscience Publishers, New York, 1962, pp 177-200.

Bates, H., "Sinter Bed Ignition," Journal, Iron and Steel Institute,
Vol. 187, 1957, pp 310-314.

Ridgion, J. M., "Ignition Conditions in Sintering," Proceedings, AIME
Blast Furnace, Coke Oven and Raw Materials Conference, Vol. 20, 1961,
pp 351-356.

Ball, D. F. and Ridgion, J. M., "Use of Preheated Air in Sintering,"
Proceedings, AIME Blast Furnace, Coke Oven and Raw Materials Conference,
Vol. 19, 1960, pp 409-421.

Rausch,. H. and Meyer, K., "Mixed Firing to Save Solid Fuel in Sinter-
ing," Second Symposium on Iron Ore Sintering, Paris, 1957; Iron and
Coal Trades Review, Vol. 175, August 16, 1957, pp 389-394.

Rausch, H. and Cappel, F., "Comparison Between Conventional, Hot Air,
and Mixed Fired Sintering," Agglomerat ion, Interscience Publishers, New
York, 1962, pp 455-476.

Jennings, R. F., "The Rating of Sinter Plants for Economic Output,"
Journal, Iron and Steel Institute, Vol. 175, 1953, pp 248-256.

Bates, H., "The Effect of Leakage on a Sinter Plant Fan," Journal,
Iron and Steel Institute, Vol. 184, 1956, pp 428-433.

Khokhlov, D. G. and Komornikov, G. I., "Influence of Moisture and Fine-
ness of Grinding of Concentrate on Quality of Mixing and Sinter Strength,'
Stal, No. 3, 1967, pp 185-188.
                                   94

-------
Zaporozhets, N. P. and Rostemberski, A. V., "Calculations of the Amount
of Waste Gas Drawn Off by the Fan from the Carbon Balance," Stal, No.
12, 1964, pp 943-944.

Korotich, V. I. and Puzanov, V. P., "Calculation of Gas-Flow Parameters
of Sintering Process," Stal, No. 7, 1967, pp 550-553.

Korotich, V. I., et al, "Operation of Drum Pelletizers," Metallurgist,
No. 1-2, 1968, pp 6-8.

Korotich, V. I., et al, "The Homogeneity of a Sintering Mix," Stal,
No. 1, 1970, pp 1-5.

Hannah, J. F. and Hass, K. P., "Sized Limestone for Iron Ore Sintering,"
AIME Ironmaking Proceedings, Vol. 23, 1964, pp 287-302.

Frame, C. P., "Improvements at Inland's No. 3 Sintering Plant and
Additions Needed to Meet Changes in the Sintering Process," TMS-AIME
Ironmaking Proceedings, Vol. 29, 1970, pp 319-327.

Belotserkovskii, Ya. L. and Maizel, G. M., "Harmful Inleakage on Strand-
Type Firing Machines," Stal, No. 12, 1970, pp 939-941.

Berry, P. M., "Continuous Measurement of Moisture in Sinter-Plant Raw
Materials," Journal, Iron and Steel Institute, Vol. 202, 1964, pp 569-
576.

Nummela, W., et al, "Moisture and Chemistry Control in Sinter Plant
Automation," Journal of Metals, Vol. 17, 1965, pp 1326-1329.
                                   95

-------
SINTER PLANT EMISSIONS AND CONTROL

Manning, G. E. and Rower, F. E., "A Characterization of Air Pollutants
from Sinter Plant Induced Draft Stacks," TMS-AIME Ironmaking Proceed-
ings, Vol. 30, 1971, pp 452-460.

Suitlas, J. R., "Emission Characteristics and Pilot Plant Studies on a
Sintering Plant Windbox Discharge," TMS-AIME Ironmaking Proceedings,
Vol. 30, 1971, pp 461-468.

Young, Jr., T. A., "Gary Works Experience with Dust Control at Number 3
Sinter Plant," TMS-AIME Ironmaking Proceedings, Vol. 30, 1971, pp 471-
479.

Bayr, R. B. and Wachowiak, R. J., "Elimination of Hydrocarbon Emissions
from the Sinter Plant," TMS-AIME Ironmaking Proceedings, Vol. 31, 1972,
pp 55-58.

Steiner, B. A. and Rower, F. E., "Pilot Plant Testing of High-Energy
Scrubbers for Sinter Plant Gas Cleaning," TMS-AIME Ironmaking Proceed-
ings, Vol. 31, 1972, pp 59-69.

Nowak, T. T., "Sinter Plant Baghouse," TMS-AIME Ironmaking Proceedings.
Vol. 31, 1972, pp 74-84.

Yatsunami, K., "Sintering for High Productivity Blast Furnace Opera-
tion," TMS-AIME Proceedings, Vol. 28, 1969, pp 107-121.

Stirling, H. T. and Kinsey, F. W., "Improved Techniques for Processing
Steel Plant Fines," TMS-AIME Ironmaking Proceedings, Vol. 25, 1966, pp
148-152.
                                   96

-------
Pugh, J. L. and Fletcher, L. N., "Experience in Handling and Consuming
Basic Oxygen Flue Dust in a Sintering Plant," TMS-AIME Ironmaking
Proceedings, Vol. 31, 1972, pp 329-331.
                                   97

-------
                               SECTION X
                              APPENDICES
                                                       PAGE
A    FIELD TEST DATA FOR WEIRTON'S NO. 2
      SINTER PLANT                                       99

B    PROCESS DESIGN CALCULATIONS                        109
                                   98

-------
                              APPENDIX A
        FIELD TEST DATA FOR WEIRTON STEEL'S NO. 2 SINTER PLANT
GENERAL

The following sections contain field test data from the files of the
Weirton Steel Division, National Steel Corporation Environmental Control
Department.  The field testing was conducted to determine the concentra-
tion and mass loading of emissions from the stack serving the Weirton
Steel Division No. 2 Sinter Machine windbox system.  In addition, the
effluent gas from each individual windbox on the No. 2 Sinter Machine
was analyzed to determine its composition.  This data represents the
most recent testing of the No. 2 Sinter Machine main windbox gas dis-
charge system.
NO. 2 SINTER PLANT MAIN STACK TESTING

A sampling program was developed by Weirton Steel Division to character-
ize emissions from the main stack at the No. 2 Sinter Plant.  This
program was conducted during July, 1971.  Sampling procedures used for
the program differed from Environmental Protection Agency recommended
methods, since the program preceded the adoption of these methods.
However, techniques were utilized which conformed to accepted practices
at the time; for example, particulate determinations were performed
according to Power Test Code 27, which includes average point sampling.
Table 15 summarizes the stack parameters.  Tables 16 through 19 present
the data taken during the test period.
                                   99

-------
Table 15.   SUMMARY OF STACK TEST DATA
Parameter
Gas flow
Particulate
Moisture
Sulphur dioxide
Condensable hydrocarbons
Stack gas temperature
Sinter machine charge rate
Total enthalpy
Nm3/s
(scfm)
mg/m
(grains/scf)
(weight) %
mg/m
(ppm)
mg/m
(grains/scf)
°C
(°F)
mtph
(tph)
j/g
(Btu/lb)
Average
163.4
(373,000)
496.5
(0.217)
3.52
250.25
(94)
160.2
(0.07)
132
(270)
336
(370)
247
(106.4)
                   100

-------
                                Table  16.   PARTICULATE EMISSIONS DATA
Test
No.
1

2
3

4

5

6

7

8

9

10

11

Average
1971
Date
7-13

7-14
7-15

7-19

7-20

7-20

7-21

7-22

7-22

7-28

7-28


Water
weight
%
3.84

3.31
3.62

2.92

3.82

3.75

3.80

3.59

3.36

3.27

3.5

3.52
Particulate
mg/m3 (a)
(grains /scf)
263.12
(0.115)
-
251.68
(0.110)
858.0
(0.375)
514.8
(0.225)
702.42
(0.307)
411.84
(0.180
393.54
(0.172)
576.58
(0.252)
—

-

496.5
(0.217)
kg/rat
(Ibs/ton)
0.496
(0.99)
-
0.476
(0.95)
1.62
(3.24)
0.973
(1.946)
1.327
(2.654)
0.878
(1.757)
0.743
(1.486)
1.089
(2.178)
_

_

0.938
(1.876)
Hydrocarbons
mg/m^
(grains/scf)
„

-
130.42
(0.057)
205.92
(0.090)
—

—

_

_

—

141.86
(0.062)
162.45
(0.071)
160.16
(0.070)
kg/mt
(Ibs/ton)
_

-
0.246
(0.492)
0.389
(0.778)
-

-

_

_

-

0.269
(0.538)
0.304
(0.608)
0.303
(0.605)
Sulfur Dioxide
mg/m-5
(ppm) (b)
_

-
-

-

—

—

332.78
(125)
223.63
(84)
193.34
(73)
_

_

250.25
(94)
kg/mt
(Ibs/ton)
_

-
-

—

-

-

0.692
(1.384)
0.465
(0.930)
0.405
(0.810)
_

_

0.52
(1.04)
(a)  mg/m-5 at  standard  conditions,  21°C  (70°F)  and 1.0 atmosphere pressure
(b)  ppm by volume

-------
     Table 17. SINTER MIX COMPOSITION
Metric tons per hour (short tons per hour)

Labrador ore
Hanna ore
Lauretta ore
Coke breeze
Flue dust
Roll scale
Filter cake
Spore stone
Correy stone
Total
%
29.5
25.85
1.47
7.28
2.57
2.91
2.81
14.75
12.73

FeO

-
-
-
-
7.16
(7.90)
-
-
-
7.16
(7.90)
Fe203
77.27
(85.20)
57.32
(63.20)
2.60
(2.87)
0.39
(0.43)
2.31
(2.55)
-
2.30
(2.54)
0.24
(0.26)
0.21
(0.23)
142.64
(157.28)
Fe304
-
-
-
0.37
(0.41)
2.24
(2.47)
-
2.27
(2.50)
-
-
4.88
(5.36)
CaC03
-
-
-
-
-
-
-
31.38
(34.6)
18.14
(20.0)
49.52
(54.2)
MgC03
-
-
-
-
-
-
-
5.90
(6.50)
15.60
(17.20)
21.50
(23.70)
                     102

-------
           Table 17. (continued)
Metric tons per hour (short tons per hour)
CaO
0.048
(0.053)
0.062
(0.068)
0.022
(0.024)
0.011
(0.012)
0.274
(0.302)
0.050
(0.055)
0.041
(0.045)
-
-
0.503
(0.555)
MgO
0.039
(0.043)
0.151
(0.166)
0.006
(0.007)
0.091
(0.100)
0.170
(0.187)
0.033
(0.036)
0.114
(0.126)
-
-
0.603
(0.665)
Si02
6.13
(6.76)
7.39
(8.15)
0.57
(0.63)
0.96
(1.06)
0.28
(0.31)
0.03
(0.03)
0.66
(0.73)
0.85
(0.94)
0.10
(0.11)
16.98
(18.72)
A1203
1.11
(1.22)
0.28
(0.31)
0.04
(0.04)
0.43
(0.47)
0.12
(0.13)
0.01
(0.01)
0.10
(0.11)
0.47
(0.52)
0.06
(0.07)
2.61
(2.88)
C
-
-
-
15.51
(17.10)
1.19
(1.31)
-
1.52
(1.68)
-
-
18.22
(20.09)
S
0.006
(0.007)
0.008
(0.009)
-
0.190
(0.210)
0.021
(0.023)
0.028
(0.031)
0.003
(0.003)
0.013
(0.014)
0.020
(0.022)
0.289
(0.319)
P
0.063
(0.069)
0.034
(0.038)
0.003
(0.003)
-
-
-
-
-
-
0.100
(0.110)
Mn
0.412
(0.454)
0.204
(0.225)
0.210
(0.232)
-
-
-
-
-
-
0.826
(0.911)
                     103

-------
Table 18.  WINDBOX GAS FLOW AND TEMPERATURE  (EXISTING  SYSTEM)
Windbox
number
1
2
W 3
E 4
S 5
T 6
7
S 8
I 9
D 10
E 11
12
13
14
Static
Pressure
(Negative)
mm we
(in we)
566.4
(22.3)
716.3
(28.2)
622.3
(24.5)
607.1
(23.9)
635.0
(25.0)
-
617.2
(24.3)
645.2
(25.4)
640.1
(25.2)
594.4
(23.4)
635.0
(25.0)
604.5
(23.8)
472.4
(18.6)
' 502.9
(19.8)
Temp.
°C
(°F)
74
(165)
76
(168)
81
(178)
77
(171)
76
(169)
-
84
(184)
103
(217)
103
(217)
136
(276)
161
(321)
246
(475)
295
(563)
274
(526)
Wind
m3/s
(acfm)
9.39
(19984)
11.53
(24531)
5.29
(11256)
11.34
(24132)
10.25
(21804)
-
7.51
(15981)
4.13
(8796)
15.50
(32984)
8.33
(17728)
15.08
(32084)
18.54
(39443)
17.46
(37153)
26.75
(56912)
Pressure
atmos.
Pa mm we
(in we)
9555.5
(376.2)
9405.6
(370.3)
9499.6
(374.0)
9514.8
(374.6)
9486.9
(373.5)
-
9504.7
(374.2)
9476.7
(373.1)
9481.8
(373.3)
9527.5
(375.1)
9486.9
(373.5)
9517.4
(374.7)
9649.5
(379.9)
9619.0
(378.7)
Pressure
water vap.
Pwv mm we
(in we)
548.6
(21.6)
538.5
(21.2)
546.1
(21.5)
546.1
(21.5)
543.6
(21.4)
-
546.1
(21.5)
543.6
(21.4)
543.6
(21.4)
548.6
(21.6)
543.6
(21.4)
546.1
(21.5)
553.7
(21.8)
553.7
(21.8)
                              104

-------
Table 18. (continued)
Pa-Pwv
mm we
(in we)
9006.8
(354.6)
8867.1
(349.1)
8953.5
(352.5)
8968.7
(353.1)
8943.3
(352.1)
8958.6
(352.7)
8933.2
(351.7)
8938.3
(351.9)
8978.9
(353.5)
8943.3
(352.1)
8971.3
(353.2)
9095.7
(358.1)
9065.3
(356.9)
Temp
°K
(°R)
347
(625)
349
(628)
354
(638)
351
(631)
349
(629)
358
(644)
376
(677)
376
(677)
409
(736)
434
(781)
519
(935)
568
(1023)
548
(986)
Wind
Nm3/s
(scfm)
6.47
(14700)
7.81
(17750)
3.56
(8100)
7.72
(17550)
7.02
(15950)
5.02
(11400)
2.62
(5950)
9.79
(22250)
4.88
(11100)
8.27
(18800)
8.54
(19400)
7.41
(16850)
11.79
(26800)
Enthalpy
dry gas
EDG
kw
(Btu/m x 103)
620.6
(35.3)
766.5
(43.6)
376.2
(21.4)
777.0
(44.2)
696.2
(39.6)
539.7
(30.7)
348.1
(19.8)
1306.2
(74.3)
852.6
(48.5)
1742.2
(99.1)
2746.0
(156.2)
2883.1
(164.0)
4254.4
(242.0)
Enthalpy
water vap.
EWV
kw
(Btu/m x 103)
835.1
(47.5)
1010.9
(57.5)
462.4
(26.3)
1002.1
(57.0)
907.1
(51.6)
652.2
(37.1)
344.6
(19.6)
1283.3
(73.0)
659.3
(37.5)
1135.7
(64.6)
1239.4
(70.5)
1116.3
(63.5)
1715.8
(97.6)
          105

-------
Table 19. WINDBOX GAS FLOW AND TEMPERATURE (EXISTING SYSTEM)
Wind box
number
1
2
E 3
A 4
S 5
T 6
7
S 8
I 9
D 10
E 11
12
13
14
Static
Pressure
(Negative)
mm we
(in we)
558.8
(22.0)
647.7
(25.5)
607.1
(23.9)
584.2
(23.0)
627.4
(24.7)
645.2
(25.4)
673.1
(26.5)
650.2
(25.6)
624.8
(24.6)
609.6
(24.0)
670.6
(26.4)
586.7
(23.1)
411.5
(16.2)
533.4
(21.0)
Temp
°C
(°F)
72
(161)
72
(161)
66
(150)
59
(138)
61
(141)
57
(134)
67
(152)
88
(191)
105
(221)
110
(230)
142
(287)
207
(404)
257
(495)
246
(475)
Wind
m-Vs
(acfm)
8.60
(18296)
5.91
(12567)
6.39
(13597)
5.98
(12723)
8.33
(17732)
11.77
(25044)
9.71
(20667)
8.39
(17860)
5.91
(12567)
10.39
(22105)
9.97
(21248)
13.22
(28132)
10.99
(23386)
34.68
(73783)
Pressure
atmos
Pa mm we
(in we)
9563.1
(376.5)
9474.2
(373.0)
9514.8
(374.6)
9537.7
(375.5)
9494.5
(373.8)
9476.7
(373.1)
9448.8
(372.0)
9471.7
(372.9)
9497.1
(373.9)
9512.3
(374.5)
9451.3
(372.1)
9535.2
(375.4)
9710.4
(382.3)
9588.5
(377.5)
Pressure
water vap.
Pwv mm we
(in we)
548.6
(21.6)
543.6
(21.4)
546.1
(21.5)
548.6
(21.6)
543.6
(21.4)
543.6
(21.4)
541.0
(21.3)
541.0
(21.3)
543.6
(21.4)
546.1
(21.5)
543.6
(21.4)
548.6
(21.6)
558.8
(22.0)
551.2
(21.7)
                              106

-------
Table 19.  (continued)
Pa-Pwv
mm we
(in we)
9014.5
(354.9)
8930.6
(351.6)
8968.7
(353.1)
8989.1
(353.9)
8950.9
(352.4)
8933.2
(351.7)
8907.8
(350.7)
8930.6
(351.6)
8953.5
(352.5)
8966.2
(353.0)
8907.8
(350.7)
8986.5
(353.8)
9151.6
(360.3)
9037.3
(355.8)
Temp
°K
(°R)
345
(621)
345
(621)
339
(610)
332
(598)
334
(601)
330
(594)
340
(612)
362
(651)
378
(681)
383
(690)
415
(747)
480
(864)
530
(955)
519
(935)
Wind
Nm3/s
(scfm)
5.96
(13550)
4.07
(9250)
4.49
(10200)
4.29
(9750)
5.96
(13550)
8.51
(19350)
6.78
(15400)
5.52
(12550)
3.74
(8500)
6.47
(14700)
5.72
(13000)
6.56
(14900)
5.04
(11450)
16.02
(36400)
Enthalpy
dry gas
EDG
kw
(Btu/m x 103)
559.0
(31.8)
379.7
(21.6)
383.2
(21.8)
327.0
(18.6)
460.6
(26.2)
625.8
(35.6)
588.9
(33.5)
634.6
(36.1)
506.3
(28.8)
914.2
(52.0)
1068.9
(60.8)
1775.6
(101.0)
1714.1
(97.5)
5150.9
(293.0)
Enthalpy
water vap .
EWV
kw
(Btu/m x 103)
770.0
(43.8)
525.6
(29.9)
525.6
(29.9)
550.3
(31.3)
766.5
(43.6)
1084.7
(61.7)
872.0
(49.6)
722.5
(41.1)
495.8
(28.2)
857.9
(48.8)
773.5
(44.0)
1107.5
(63.0)
738.4
(42.0)
2338.1
(133.0)
           107

-------
NO. 2 SINTER PLANT WINDBOX GAS TESTING

Air flow measurements and gas analysis of the individual windboxes of
Weirton Steel Division No. 2 Sinter Machine were conducted January 24,
January 29, and February 7, 1973.  The following table presents the
average windbox gas compositions.
              Table 20.  AVERAGE WINDBOX GAS COMPOSITION
Windbox
Number
1
2-10
11
12
13
14
Averages
%
°2
16.6
13.4
16.1
17.3
17.9
19.2
15.4
%
co2
3.2
9.6
5.6
4.8
2.8
1.6
6.7
%
CO
0.27
1.26
0.80
0.33
0.09
0.09
0.82
                                   108

-------
                              APPENDIX B
                      PROCESS DESIGN CALCULATIONS
INTRODUCTION

The continuity, energy, and momentum equations in this section were
developed for an analysis of the waste gas recirculation system.  The
equations are developed for equilibrium conditions utilizing equations
of state, heat transfer equations, and combustion and chemical data.
After the equations were developed, system parameters were determined
for selected recirculation rates.  Computations using these equations
established the 39% recirculation rate as optimum and provided the basis
for the design and selection of the waste gas recycle system equipment.
Values obtained from the computations are summarized in Table 14, page
62.
DESIGN BASIS (Existing System - 0% Recirculation)
Machine Size
Width                         3.7 m (12')
14 Windboxes, each          .  3.7 m (12'-0") x 3.2 m (10'-6")
Bed area                      163.5 m2 (1760 ft2)
Bed thickness                 355.6 mm (14 in)
Pressure drop across
  bed and windboxes           762 mm  (30 in)
Ignition furnace
  Fuel                        Coke oven gas
  Length                      1.5 windboxes
                                   109

-------
Rated Production

Sinter product                 263 metric  tph
                               (290 short  tph)
Basicity ratio                 2.0

Normal Feed Rate

Feed including hearth          336 metric  tph
  layer and hot fines          (370 short  tph)

Sinter Cooler Feed

Hot sinter to cooler           268 metric  tph
                               (295 short  tph)

Waste Gas Data

The following data is extracted or derived from the tables in Appendix A
and other test data from the No. 2 Sinter Machine.

Total dry air                  180.02 Nm3/s (409,150 scftn)
                               233.1 kg/s  (511.4 Ibs/sec)

Total moisture                 Based on 3.52% moisture from
                               Table 15 of Appendix A
                               8.85 kg/s (19.5 Ibs/sec)
Enthalpy                      E__ = 32997.6 kw
                                    (1.877 x 10  Btu/min)
                                  = 141.56 j/g
                                    (61.16 Btu/lb)
                                   110

-------
                                  = 24492.4 kw
                                    (1.393 x 106 Btu/min)
                                  = 2767.50 j/g
                                    (1191.8 Btu/lb)

System Pressure Drop

Once Through System - 0% recirculation

                              mm we          inches we

Pressure drop across
  sinter bed                  762            (30)

Pressure drop across
  cyclones                    203            ( 8)

Pressure drop across
  ductwork                    102            ( 4)

Pressure drop from fan
  through stack              	51            ( 2)

Total system pressure drop
(Fan static pressure rise)   1118            (44)
                                   111

-------
Fan Inlet Conditions
Pressure                    -1067 ram we      (-42 inches we)
Gas Temperature               139°C          (282°F)
                                   3
Gas Volume - Each Fan         160 m Is       (240,000 acfm)
Gas Density                  0.801 kg/Nm3    (0.0464 Ib/scf)
CALCULATIONS



Each parameter listed in Table 14, page 62, is shown here, in the order

used in the table, with an explanation of its origin or derivation.



1.0  Gas Flow Each Fan (Dry)



     As previously defined in the Discussion, page 64, the total process
                            3
     wind volume is 176.0 Nm /s (400,000 scfm).  The gas flow through

     each fan is 88 Nm3/s (200,000 scfm).



2.0  Waste Gas Temperature at Fan



2.1  Equilibrium Moisture Content of Gas - Atmospheric air at 21°C

     (70°F), 50% relat

     scf) of moisture.
(70°F),  50% relative humidity contains X = 9.48 g/Nm3 (4.0 grains/
                                                           3
     Waste gas with 0% recirculation contains Y = 49.2 g/Nm  (20 grains/

     scf) of moisture.
                                   112

-------
When recirculating waste gas, moisture  content  increases.   The
general equation for moisture content as  a function of recycle
ratio is derived as follows:
with M.. = Moisture  content  above  bed
     M- = Moisture  content  below  bed
     R  = % recirculation
First pass -

                              R
»i_    „ j   x,            ... .
Above Bed:       =  -K +
Below Bed:      =        X +    Y + Y - X
Second pass -

M   =  100-R,,  .   R , 100-R,, .   R

( 100 f 100Y) (1
,100-R,, . R v. ..
Y T loo1 T L "
. R v R „
100; 100
i R \ R v
                                           v
          100      100         100  ~ 100    Y
Third pass  -

    _  100-R   ,   R  , /IOO-R  .   R
M
 1      100      100 LV  100     100 '  v

          itox + Y - x]
                                         2
..100-Ry j.  R  \  ri  ,   R_
      X +
                                   /   \   -i       Y
                                   (}   J  "    X
          100      100        100    100       100
                    Y - X
                               113

-------
                                       2

M   -  /-'y  ,  R y\ r-i  .  R   , / R s i   _JL_Y

M2  "  ( 100 * + 100Y) U + 100 + C100} J " 100X
nth pass -
M
 i                 o          o
           R  3           R

       + ()  + ... +
             R      R  2           R  n~1

            100 + (100)  + ''• + <>
M2  =  MI + Y - X




            R              R  n~1
Since -1 <    r <  1 then (V/T)    will approach zero as n increases
and the sum of n-1 terms will approach
                                       1-  R
                                           100

   100
         as a limit.
  100-R
M   =  f"   +  R v^ 10°     R (..IPO w
       v 100     100 '100-R ~ 100V100-R^
        100-2R     R    100
_  fioo-2Rx ,  _A_v^
-  \ inn  A + inn*'
         100      100 '100-R




        100-2R     R  . 100      _

       ^ 100      100 '100-R





       Moisture content in waste gas main
                             114

-------
Moisture content at 39% recirculation - Inserting 39% recirculation into

the above equations gives the following:
     Above Bed:  M   =  1.64(0.22X + 0.39Y)
Below Bed:
                           + Y - X
     Inserting the values for X and Y gives:
     M   =  35.06 g/Nm   (14.25 grains/scf)
     M.  =  74.42 g/Nm   (30.25 grains/scf)


Moisture content at R% recirculation - The waste gas moisture content

for other recirculation  rates similarly calculated are shown in the

table below.


             Table 21.   MOISTURE CONTENT IN WASTE GAS MAIN
                     R
               % of waste gas
                  recycled
                                M- Waste gas moisture
                                   content
                                g/Nm  (gr/scf)	
                     0
                    10
                     20
                     30
                     39
                     50
                                     49.2
                                    (20.0)

                                     53.6
                                    (21.8)

                                     59.0
                                    (24.0)

                                     66.1
                                    (26.9)

                                     74.42
                                    (30.25)

                                     88.6
                                    (36.0)
                                   115

-------
2.2  Enthalpy Rise Across the Recycle Fan -

             kw                    .42.4 x bhp,
      K     kg/s                     Ibs/min
                3228               r42.4 x 4327 x 13.3,
            93^72 x 1.2953         L213,000 scfm cf/lbj
            Nm /s   kg/Nm
         =  26.6 j/g               (11.46 Btu/lb)

     Where recycle fan kilowatts when handling 93.72 Nm /s (213,000
     scfm) of waste gas = 3228 (4327 bhp) as stated by Green Fuel Co.,
     manufacturers of the recycle fan.
2.3  Recycle Gas Ductwork Heat Loss -

     Assumptions - The assumptions used in calculating the duct heat
     loss are:

          Exterior of ductwork is insulated with rigid fiberglass 2
          inches thick.  Ductwork interior is bare steel without in-
          sulation.

          Waste gas enters recycle fan at 194°C (382°F).

          Building and exterior temperature 20°C (70°F), still air.

          Recycled waste gas thermodynamically similar to air.
                                   116

-------
     Heat  loss calculations - The general equation used is:
          Q = AxU. xAT
          where Q = Heat loss,  kw (Btu/hr)


                U = Heat transfer coeff.,  kw/m2°K (Btu/hr ft °F)
    AT  =  Waste gas temp.  - ambient temp. °K (°F)

                          2    2
     A  =  Surface area, m  (ft )
                     Table 22.  DUCTWORK HEAT LOSS
Location
1. Insulated
ductwork
2. Cyclones
(Lined, un-
insulated)
3. Waste Gas
mains (bare
steel)
4 . Downcomers &
Hoppers (bare
steel)
5. Insulated re-
cycle ducts
from fan to
machine hood
6. Uninsulated
machine hood
Surface
area
m2 (ft2)
1,468
(15,800)
260
(2,800)
1,412
(15,200)
1,412
(15,200)
1,612
(17,350)
139
(1,500)
Heat loss
Q, kw
(Btu/h)
275
(940,000)
322
(1,100,000)
5,391
(18,400,000)
5,860
(20,000,000)
346
(1,180,000)
176
(600,000)
Heat
Trans .
Coef.
0.0011
(0.19)
0.0071
(1.25)
0.0207
(3.65)
0.0215
(3.8)
0.0011
(.19)
0.0150
(2.65)
Temp.
Diff.
°K (°F)
173
(312)
175
(315)
184
(332)
193
(347)
219
(395)
83
(150)
Total recirculated
gas heat loss (Q ) :
                R
     QR = 0.39(Q1 + Q3 + Q4) + Q5 + Q6



        = 5143 kw (17,500,000 Btu/h)
                                   117

-------
Enthalpy loss (IL):

     H          5143
     T)   73.04 x 1.295
        = 54.37 j/g (23.4 Btu/lb)
2.4  Recirculated Gas Temperature Equilibrium - The enthalpy of out-
     side air at 21°C (70°F) and 50% relative humidity is:
          "A ' EDG
             = 21.219 +      x 2537.55
             = 39.8 j/g            (17.4 Btu/lb)
     The enthalpy of waste gas at the fan inlet when operating with 0%
     recirculation, 139°C (282°F) and 49.2 g/Nm3 (20 grains/scf) of
     moisture is:
          HB " EDG + D X EWV
             = 141.56 +      x 2767.5
             = 246.7 j/g           (106.1 Btu/lb)

     The enthalpy gain less ductwork loss is:
             = 26.6 - 54.37
             =-27. 77. j/g          (-11.9 Btu/lb)
                                   118

-------
When recirculating waste gas, the gas  temperature increases.  The
general equation for thermal equilibrium as a function of recycle
ratio is derived as follows:
     with  H-  = Gas enthalpy above bed
           H_  = Gas enthalpy below bed
           R  = % recirculation
First pass  -
Above bed:      =    =    +      ^ + H(,)
                             R
Below bed:   H  = -       + _  (HB +  V  +
Second  pass -
Hl = TOOA + TOO [~TOTHA + TOO  (HB  + HC}  + HC + HB

   =             100 (HB + HC} ]  (1  + IOO) ~ IOOHA
H2 =  [1I§6\ + 155 (HB + V]  (1 + lfe>  - llo^A + =8 * HA
 £.      J-V/V_/  c\.   j-\J\J   Jj    \j         j~\J\J    ±\J\J £\.    JD    /\
nth pass  -
        R  n-1                           2            n-2
        **• \    1     .": TT   T-l 4.  "•   •  /  K \   .      / "• \   -l
              J           U   100    1;      * '  1;   J
                               119

-------
           Dp                   T?       T?
u  - JJ-
-------
Gas enthalpy below bed H  = E  + H  - H
                        tm    JL    15    A
Inserting the values for HA, H  and H  gives
                          A   D      (_»

     H-L = 156.13 j/g          (67.2 Btu/lb)
     H2 = 361.45 j/g          (155.6 Btu/lb)

The temperature of the gas above the bed  (using H  and tables for
air) is:
     T  = 84°C       (183°F)
     From tables  (check calculation)

     Hl = EDG1 +  D X EWV1

        = 84.45 + ^:^6 x 2647.72 = 156.13 j/g  (67.2 Btu/lb)
The temperature of the gas entering the fans  (using H9 and tables
for air) is:

     T2 = 194°C      (382°F)

     From tables  (check calculation)
        = 196.88 +    <   x  2862-03 =  361.45 j/g  (155.6  Btu/lb)
                              121

-------
3.0  Pressure Drop Across 355.6 mm (14 in) Sinter Bed




     At 39% recirculation, the pressure drop across the sinter bed due


     to temperature change, using Sutherland's formula for viscosity is:
                      T  -4-
     AP = AP (  )    (lQ *    ) mm we    (in we)
            0 T0      T + 120


                71 4. 1 TO
     where TQ =    ^     + 273 = 353°K        (636°R)  (Zero Recycle)




           T  = 84 * 194 + 273 = 412. 5°K      (742. 5°R)  (39% Recycle)
          AP  = 762 mm we                     (30 in)
            o


      p „ 760 ,412.5 *'5 . 353 + 120
          /oz ^     ;    ^      + 120;
          856 mm we                           (33.7 in)
4.0  Pressure Drop Existing Cyclones




     For 39% recirculation, the pressure drop across the cyclones, using

     temperature correction,



                  467
          = 203 x   l = 230 mm we            (9 in)
5.0  Pressure Drop Ductwork to Fan




     For 39% recirculation, the pressure drop across the existing duct-

     work, using temperature correction,



                  4fi7
          - 102 x —• = 116 mm we            (4.5 in)
                                   122

-------
     The pressure drop across new ductwork

          = 20 mm we                         (0.8 in)

     The total pressure drop across the ductwork to the fan

          = 136 mm we                        (5.3 in)


6.0  Fan Inlet Negative Pressure

     At 39% recirculation, the sum of the pressure drop is -1220 mm
     we (-48 in) at 194°C (382°F)


7.0  Gas Volume at Fan Inlet

     At 39% recirculation the gas flow including moisture

          = 93.72 Nm3/s                      (213,000 scfm)

     Correcting this for gas density gives

          184.7 m3/s                         (393,000 acfm)


8.0  Gas Density

     At 39% recirculation, the density corrected to inlet conditions
     gives 0.646 kg/m3 (0.0403 Ibs/cf)
                                   123

-------
9.0  Pressure Drop Fan to Hood



     At 39% recirculation, the pressure drop in the duct from the fans

     to the hood = 70 mm we (2.8 in)
10.0 Fan Static Pressure



     At 39% recirculation, the sum of fan inlet pressure and drop to

     hood = 1290 mm we (50.8 in)


                                               3
     Two fans, each with a capacity of 184.71 m /s (393,000 acfm) at
               3
     0.646 kg/m  (0.0403 Ib/cf) density are required.
11.0 Fan Power



     At 39% recirculation, the fan power determined by the fan manufac-

     turer is 3228 kw (4327 bhp).
12.0 Volume Recycled (Dry)
                                                             •3
     Recirculation of 39% of the total dry gas flow of 176 Nm /s

     (400,000 scfm) = 68.6 Nm3/s (156,000 scfm).
13.0 Volume Recycled to Hood
     The standard volume of 68.6 Nm /s (156,000 scfm) recycled, cor-
                                  3
     rected for density = 136.88 m /s (290,000 acfm).
                                   124

-------
14.0 Waste Gas Composition

14.1 Operating Conditions - The waste gas analysis is based on a sinter
     production rate of 263 mtph (290 net stph) with a basicity ratio of
     2.0 and a sinter mix composition as shown in Appendix A, Table 17.

14.2 Oxygen Loss to Sinter Bed - The oxygen used in the oxidation of
     metallics and the combustion of fuel in the sinter feed is deter-
     mined as follows:
     FeO to Fe203 (4FeO + 02 to
            7.16 x 1000 x 1000 x 22.4       32
                                      x
                3600 x 32 x 1000        4 x 71.85
          = 0.1550 Nm3/s                     (353.7 scfm)
           to Fe00_  (4Fe_0. + 00 to
                ^3     34    2       z j
            4.88 x 1000 x 1000 x 22.4       32
                3600 x 32 x 1000        4 x 231.55
            0.0328 Nm3/s                     (74.7 scfm)
     C to C02  (C + 02 to C02)
            18.22 x 1000 x 1000 x 22.4   .32
                 3600 x 32 x 1000      X 12
            9.4474 Nm3/s                     (21540.9 scfm)
                                   125

-------
     MnO to Mn 0  (6MnO + Q^ to
            0.826 x 1000 x 1000 x 22.4       32
                                       x
                 3600 x 32 x 1000        6 x 54.94
            0.0156 Nm3/s                     (35.6 scfm)
     FeS2 to Fe203 + S02 (4FeS2 + 11 02 to
            0.289 x 1000 x 1000 x 22.4   11 x 32
                 3600 x 32 x 1000      X  8 x 32
            0.0773 Nm3/s                     (176.4 scfm)
14.3 Total Oxygen Loss - The summation of the above oxygen losses gives
     L = 9.728 Nm3/s                    (22,181 scfm)
     By test, the waste gas analysis should average oxygen content of
     15.4%.  See Appendix A, Table 20.  From this the oxygen loss in the
     sinter bed was determined to be
     L = 180.02 (0.21 - 0.154) = 10.03 Nm3/s      (22,800 scfm)
     This latter value is accepted as correct and is used in the sub-
     sequent calculations.

14.4 Oxygen Equilibrium as a Function of Gas Recycle Ratio - When re-
     circulating waste gas, the oxygen content decreases.  For a single
     pass system, i.e., R = 0, the oxygen content below the bed

     02 = 0.21 W - L Nm3/s (scfm), where

     L <= oxygen loss = 10.03 Nm3/s           (22,800 scfm)
     W = waste gas flow = 187.44 Nm3/s       (426,000 scfm)
     R - % recirculation
                                   126

-------
For R% recirculation,  the general  equation  for oxygen content below


the bed is derived as  follows:





First pass -





°2=llo <0.21W-L)+(0.21W)  -L
         (0'21W) - L (1 +    >  +       (0'21W)
     io   '               io



Second pass -
°2 = I5o [Bo <°-21w> - L d + I5o>
             (0.21W) - L
     (0.21W)





nth pass -
°2 - (>(0-21w) - L
                               ...




            R             R  n"1
Since -1   -      1 then (VQQ)    will approach zero  as n  in-
creases and the sum of n-1 terms will approach    1    =  100

                                                    R    100-R

                                                  100




0  = -L  10°  - 100~R '" —  10°
 2 ~    100-R    100
              10°
             100-R
                              127

-------
     % 0  Below Bed
                 21W    IPO
                .21W
                100  /lOOLv
               100-R *• W  '
       0  Above Bed
                     IPO  fiQQLn   100-R
                          V T.T  )\
          100 L     100-R v W  /J    100


14.5 39% Recirculation - Inserting the values for L, W and R for 39% re-
     circulation gives

     Oxygen Above Bed:  0  = 17.56%

     Oxygen Below Bed:  02 = 12.2%


14.6 Check on Gas Composition Using 39% Recirculation

     Carbon dioxide - The average C0_ in the waste gas at 0% recircu-
     laton is 6.7%.  (Ref. Table 20, page 108.)

     Using this, C02 = W(0.067) (1.64) gives C02 = (6.7) (1.64) =
     10.9% below the bed.

     In the recycle hood, at 39% recirculation, CO  = (0.39) (10.9) =
     4.25%

     Carbon monoxide - The average CO in the waste gas main at 0% re-
     circulation = .82%.  (Ref. Table 20, page 108.)

     This gives CO = (0.82) (1.64) = 1.34% below the bed.
                                   128

-------
     In the recycle hood at 39% recirculation CO = (0.39)  (1.34)  = 0.53%

     Gas composition summary - A summary of the calculated and derived
     gas composition values follows in Table 23.

                       Table 23.  GAS COMPOSITION
                           39% Recirculation
Gas
°2
co2
CO
N2
H2°
TOTAL
Above
Bed
%
17.5
4.2
0.5
73.6
4.2
100.0
Below
Bed
%
12.2
10.9
1.3
67.1
8.5
100.0
14.7 Calculated Gas Density - The gas density above and below the bed is
     calculated from the gas composition data in Table 23.

     Above bed -
         0.045 x 32 x 0.175
         0.045 x 44 x 0.042
         0.045 x 28 x 0.005
         0.045 x 28 x 0.736
         0.045 x 18 x 0.042
pGas @ 21°C (70°F) and
 760 mm HG (14.7 psia)
P°2   =
Pco2  =
pCO   =

pH00  =
                                       =  0.252
                                       =  0.082
                                       =  0.006
                                       =  0.920
                                       =  0.034

                                       =  1.294 kg/Nm3  (0.075 Ib/scf)
                                   129

-------
     Below bed -
          p02   =  0.045 x 32 x 0.122  =  0.176
          pCO   =  0.045 x 44 x 0.109  =  0.216
          pCO   =  0.045 x 28 x 0.013  =  0.004
          pN2   =  0.045 x 28 x 0.671  =  0.845
          pH_0  =  0.045 x 18 x 0.085  =  0.069
            2.                             —————
          pGas @ 21°C (70°F) and
           760 mm Hg (14.7 psia)       =  1.31 kg/Nm3  (0.076 Ib/scf)
15.0 Gas Flow to Stack
     Total gas flow  =  176 Nm3/s (400,000 scfm) dry.
     61% of this corrected for density at discharge conditions, 0.646
     kg/Nm3 (0.0403 Ibs/ft),

         =  212.9 m3/s        (453,000 acfm)
16.0 Saturated Gas Flow to Stack & Saturated Gas Temperature

16.1 General -

     Enthalpy of waste gas discharge = enthalpy at fan inlet +
                                        enthalpy rise across fan

     Using tables for saturated gas, this value will give the saturated
     gas temperature.

     The specific volume of the gas at the saturated temperature (from
     table) times the mass flow, at the percentage recirculation being
     considered, gives the saturated volume flow.
                                   130

-------
16.2 39% Recirculation -
     EI   =  Gas enthalpy at fan inlet (calculated previously)
     E-   =  Gas enthalpy rise in fan  (calculated previously)
     E   =  361.45 + 26.6
         =  388.05 j/g        (167.2 Btu/lb)

     From table:  T  =  57°C  (134°F)
     From table:  Specific volume  =  1.123 m3/kg  (18.0 ft /lb)
     Mass Flow  =  106.9 Nm3/s x 1.295 kg/Nm3
                 =  138.4 kg/s          (18,300 Ib/min)
     Saturated Volume  =  138.4 x 1.123
                        =  155.4 m3/s        (330,000 acfm)
SUMMARY

The relationships developed in Appendix B were the process design
basis for the sinter plant waste gas recirculation system at the
Weirton Steel Division No. 2 Sinter Plant.  The numerical values
derived for selected recirculation rates are summarized in Table 14,
page 62.  From these data, the 39% recirculation rate was selected
as the optimum design point.
                                   131

-------
                                  TECHNICAL REPORT DATA
                           (Please read Instructions on the reverse before completing)
 1. REPORT NO.
 EPA-600/2-75-014
                            2.
                                                        3. RECIPIENT'S ACCESSION NO.
 4. TITLE AND SUBTITLE
 Sinter Plant Windbox Gas Recirculation System
    Demonstration—Phase 1. Engineering and Design
             5. REPORT DATE
             August 1975
             6. PERFORMING ORGANIZATION CODE
 7. AUTHOR(S)
                                                        8. PERFORMING ORGANIZATION REPORT NO
 D.A.  Pengidore
 9. PERFORMING OR3ANIZATION NAME AND ADDRESS
 National Steel Corporation, Weirton Steel Division
 P.O.  Box 431
 Weirton, West Virginia 26062
             10. PROGRAM ELEMENT NO.
             1AB015; ROAP 21AQR-005
             11. CONTRACT/GRANT NO.

             68-02-1364
 12. SPONSORING AGENCY NAME AND ADDRESS
                                                        13. TYPE OF REPORT AND PERIOD COVERED
 EPA, Office of Research and Development
 Industrial Environmental Research Laboratory
 Research Triangle Park, NC  27711
             Final; 6/73 - 3/75
             14. SPONSORING AGENCY CODE
 15. SUPPLEMENTARY NOTES
 16. ABSTRACT
           Windbox gas recirculation, as applied to a sinter plant, involves the return
 of a portion of the windbox exhaust gas to a hood above the sinter bed.  The report
 develops the tradeoffs of recycle ratio versus oxygen content, moisture content,  and
 temperature of the gases about the bed; total power consumption; and other important
 parameters.  The basis for this parametric study, as well as for the full scale design
 developed therefrom,  is operational and emissions data from two large modern sinter
 plants., taken as part of this effort. Recycle is projected to reduce hydrocarbon emis-
  ions to acceptable levels at reduced power consumption and capital cost relative to
 more conventional approaches. The advantages  and disadvantages of various devices
 :or  final control of particulates are weighed: a gravel bed filter was  the final choice.
 The report describes Phase 1 of a 2-phase project. Phase 2 will consist of an
  xtensive  test and evaluation of the full scale windbox gas recirculation system
 installed at  the National Steel  Corporation, Weirton Steel Division, sinter  plant.
 7.
                              KEY WORDS AND DOCUMENT ANALYSIS
                 DESCRIPTORS
                                           b.IDENTIFIERS/OPEN ENDED TERMS
                         c. COSATl Field/Group
 Air Pollution
 Sintering Furnaces
 ron and Steel Industry
 Dust
 Hydrocarbons
  ost Effectiveness
Air Pollution Control
Stationary Sources
Windbox
Gas Recirculation
Particulates
Gravel Bed  Filters
13B
13A
11F

07C
14A
 8. DISTRIBUTION STATEMEN1

 Unlimited
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES

    140
                                           20. SECURITY CLASS (Thispage)
                                           Unclassified
                                                                    22. PRICE
EPA Form 2220-1 (9-73)
                                        132

-------