CD
o.
                                     74-KPM-IO
AIR  POLLUTI
EMISSION  TEST
                  WEYERHAEUSER COMPANY
                  KRAFT MILL
                  EVERETT WASHINGTON
         UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
               Office of Air and Waste Management
             Office of Air Quality Planning and Standards
                Emission Measurement Branch
              Research Triangle Park, North Carolina

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      PARTICULATE EMISSION MEASUREMENTS

           PROM KRAFT PULP MILLS
           EMB Projects Report No.
                  7-4-KPM-10
                Plant Tested

  Weyerhaeuser Company, Everett, Washington


              October 9-12, 1973


                Prepared for

       Environmental Protection Agency
Office of Air Quality Planning and Standards
         Emission Measurement Branch
           Research Triangle Park
            North Carolina  27711
                     by

             W. R.  Feairheller
               D. L.  Harris
               M. T.  Thalman
       MONSANTO RESEARCH- CORPORATION
             DAYTON LABORATORY
             1515 Nicholas Road
            Dayton, Ohio  45^07
    Report Reviewed by Robert M.  Martin

     Contract No. 68-02-0226, Task No. 11

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                   TABLE OP CONTENTS
                                                   Page
  I.    INTRODUCTION                                  1
 II.    SUMMARY AND DISCUSSION OF RESULTS            . 3
III.    PROCESS DESCRIPTION AND OPERATION             6
 IV.    LOCATION OP SAMPLING POINTS                  1?
  V.    SAMPLING AND ANALYTICAL PROCEDURES           21
                      ill

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                       LIST OF FIGURES

                                                        Page
1.    The Kraft Pulping Process                            7
2.    Smelt Dissolving Tank and Scrubber at the
     Weyerhaeuser Mill at Everett,  Washington            10
3.    Inlet and Outlet of Weyerhaeuser Company
     Scrubber                                            19
4.    Traverse Point Locations                            20
                       LIST OF TABLES

                                                        Page

1.    Summary of Particulate Results                       5

2.    Summary of the Recovery Furnace and
     Packed Tower Process Data                           12

3.    Summary of Calculations of Equivalent Pulp
     Production Rate                                     16
                           iv

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                      I.    INTRODUCTION

Under the Clean Air Act of 1970, the Environmental Protection
Agency is given the responsibility of establishing perform-
ance standards for new installations or modifications to
existing installations in stationary source categories.  As
a contractor, Monsanto. Research Corporation (MRC), under the
Environmental Protection Agency's "Field Sampling of
Atmospheric Emissions" program, was asked to provide emis-
sion data from the Weyerhaeuser Company, Everett, Washington.

The field test work was directed by John Snyder, Field Test-
ing Section, Emission Measurement Branch.  The sampling was
performed by Monsanto Research Corporation with Darrell L.
Harris as Team Leader.

This report tabulates the data collected at the outlet of
the wet scrubber system controlling the exhaust of the smelt
tank.  The smelt tank is  part of the overall recovery system
of the kraft pulp mill.  Spent digestion chemicals (black
liquor) are burned in a recovery furnace and smelt is formed
in the bottom of the furnace.  This smelt is. continuously re-
moved from the furnace and fed into the smelt  dissolving tank
where it is dissolved in  scrubbing liquor or makeup water to
make the uncausticlzed green liquor.  Gaseous  emissions from
the smelt dissolving tank are scrubbed in a packed tower
scrubber and emitted to the atmosphere.

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Sampling was performed on the outlet of the packed tower
scrubber.  Particulate loadings were determined by Method 5,
"Determination of Particulate Emissions from Stationary
Sources."  Other procedures that were required for the
Method 5 tests were:  Method 1, "Sample and Velocity Tra-
verses for Stationary Sources;" Method 2, "Determination "of
Stack Gas Velocity and Volumetric Plow Rate (Type S Pitot
Tube);" Method 3, "Gas Analysis for Carbon Dioxide, Excess
Air and Dry Molecular Weight;" and Method 4, "Determination
of Moisture in Stack Gases."  All of the above methods are
given in the Federal Register, Vol. 36, No. 247, Dee. 23,
1971.

The modification required at the sampling location was to
provide a support surface for the sampling equipment.

This report presen'ts a summary and discussion of sampling
results, a description of the process, the location of sam-
pling points an.d a description of the sampling and analyti-
cal procedures.  Appendices contain all field and analytical
data generated from this project.

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          II.   SUMMARY AND DISCUSSION OF RESULTS

The outlet of the packed tower scrubber system of the smelt
dissolving tank at the Weyerhaeuser Company's kraft pulp mill
was sampled for particulate loading.  An attempt was made to
sample the Inlet of this scrubber, but the flow was erratic
and Irregular at the only available sampling location.  At
some point locations.flow direction was actually reversed.
After discovering the flow discrepancies, the inlet sampling
was aborted.

A total of six runs were attempted on the outlet, but only
three of the six were valid runs.  Prior to the first run a
Method 4 moisture determination was performed, as well as a
velocity traverse according to Methods 1 and 2.  The mois-
ture analysis indicated that the stack gases contained ap-
proximately 18.5% water by volume.  This moisture value did
not seem reasonable in view of the fact that the effluent
was the outlet of a scrubber and saturated gas .was expected.
To recheck this calculation a wet bulb-dry bulb moisture
check was made and it indicated that the moisture level was
17% by volume. ' Because of the agreement of the two methods,
it was assumed that they were correct, and a value of 18$
was used to calculate the nomograph factor.  During the first
half of the run the sampling train plugged several times and
had to be shut down and restarted.  At the half way shutdown
for port change, the excess water was removed from the im-
pingers, the silica gel replaced and the run continued.

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During the second half of the run rough calculations were
made for the first half, and they indicated a moisture con-
tent of approximately 40$ and an isokinetic percentage of
about 145$.  This run was aborted and the sample was not
saved.

Runs 2 and 3 were made the next day and both were calculated
to be super isokinetic.  It was determined that the stack
gases were saturated, as suspected, and the stack tempera-
ture was changing during the run, causing wide variations in
the moisture content.  It was decided that an average stack
temperature and average moisture content could not be used
to set the nomograph for the run.  Instead, the stack tem-
perature would have to be closely monitored, and adjustments
made in the nomograph 'Calculation when a temperature change
was noted.  The nomograph was therefore adjusted to each new
temperature for a moisture level equivalent to a saturated
gas at the new temperature.  The next three runs (Nos. 4,
5, and 6) were made using this procedure and turned out to
be isokinetic within the ± 10% requirement.

Table 1 summarizes the results of particulate sampling, giv-
ing particulate loadings and several of the more important
variables.  Run 1 is not listed since the partially collec-
ted sample was not saved.  Runs 2 and 3, while not within
the isokinetic specification, are given for reference.  Runs
4, 55 and 6 are the acceptable runs.

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                                                    Table  1

                                    Summary  of  Particulate  Results
Run Number:
Date:
Method Tvoe:
Volume of gas sampled - (Nm3)" - (DSCF)1
Percent Moisture by Volume
Average Stack Temperature - °C - (°P)
Stack Volumetric Flow Rate - Nrn'/sec - (DSCFM)2
Stack Volumetric Flow Rate - mVsec - (ACFM)3
Percent Isoklnetic
Feed Rate - M tons/hr of Equivalent
Pulp' Production - (tons/hr)
Duration of Run - Minutes
Particulates
Probe, Cyclone, and Filter Catch, mg
mg/Nm3 - (grains/DSCF)6
Kg/hr - (Ib/hr)
Kg/M ton of Equivalent Pulp
Production - (Ib/ton)
Total Catch - mg
mg/Nm3 - (grains/DSCF)6
Kg/hr - (Ib/hr)
Kg/ M ton of Equivalent Pulp
Production - (Ib/ton)
Percent Impinger Catch
2
10/10/73
EPA- 5
2.28 (80.5)
13.5
80.6 (177)
6590 (3880)
13800 (8110)
116.5
It. 3 (15.8)
220

559.6
215 (0.107)
1.61 (3.56)
0.113 (0.225)
613.6
270 (0.118)
1.77 (3.900)
0.124 (0.247)
8:8
3
10/10/73
EPA-5
2.10 (74.2)
47.6
81.7 (179)
5790 (3410)
13200 (7750)
121.9
17.0 (18.7)
220

628.8
300 (0.131)
1.73 (3.820)
0.102 (0.204)
678.5
323 (0.141)
1.87 (4.120)
0.110 (0.220)
7.3
4
10/11/73
EPA-5
1.93 (68.2)
44.8
78.9 (174)
6300 (3710)
13600 (8020)
104.2
15.9 (17.5)
220

503.4
261 (0.114)
1.64 (3.610)
0.103 (0'.206)
533.3
277 (0.121)
1.73 (3.820)
0.109 (0.218)
5.6
5
10/12/73
EPA-5
1.95 (69.0)
47.4
82.2 (180)
6120 (3600)
14000 (8220)
108.4
17.1 (18.8)
220

631.4
323 (0.141)
1.97 (4.350)
0.115 (0.23D
664.9
341 (0.149)
2.08 (4. 580J
0.122 (0.244)
5.0
6
10/12/73
EPA-5
1.79 (63-2)
47.8
80.6 (177)
5810 (3420)
13300 (7840)
104.6
17.3 (19.1)
220

.530.1
295 (0.129)
1.72 (3.780)
0.0994 (0.198)
556.2
311 (0.136)
1.80 (3.970)
0.104 (0.208)
4.7
'Dry-Standard  Cubic Feet  % 70°P,  29.92 in Hg
2Dry Standard  Cubic Feet  per Minute 6 70°F,  29.92 in Hg
3Actual Cubic  Feet per Minute - Stack Conditions
"Normal Cubic  Meters at 21.1°C, 760 mm Hg
5Metric Tons per Hour (1  metric ton - 1000 Kg)
6Grains per Dry Standard  Cubic Feet

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          III.   PROCESS DESCRIPTION AND OPERATION

PROCESS DESCRIPTION

A.   General

Kraft pulp Is produced from wood as shown in Figure 1.   In
the process, wood is chipped into small pieces and then
cooked (digested) under pressure at elevated temperatures
in {'white liquor"—a water solution of sodium hydroxide and
sodium sulfide.  The white liquor chemically dissolves
lignin, leaving wood cellulose (pulp) which is filtered from
the spent liquor and washed.  The pulp produced is usually
made into paper.

The balance of the process is designed to recover the cook-
ing chemicals.  Spend cooking liquor and the pulp wash  water
are combined for treatment to recover cooking chemicals.
The combined streams, called weak black liquor, are normally
concentrated to 60-65% solids in evaporators and then fired
in a recovery furnace.  Combustion of the organics in the
black liquor provides a significant portion of the heat re-
quired for generating process steam.  Inorganic chemicals
from the black liquor are recovered as a molten smelt from
the bottom of the furnace.  The smelt, consisting of so-
dium carbonate and sodium sulfide, is dissolved in water  and
transferred to a causticizing tank.  Lime added to the  tank
converts sodium carbonate to sodium hydroxide, completing

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 =}
 Q_
I
  §2

  8
  
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the regeneration of white liquor, which is then recycled to
the digesters.  The calcium carbonate mud which precipitates
from the causticizing tank is recycled to a kiln to regen-
erate lime.

B.   Smelt Dissolving Tank

The smelt dissolving tank receives a stream of molten smelt
which is continuously tapped from the bottom of the recov-
ery furnace.  The molten smelt is subsequently dissolved in
the smelt dissolving tank to form "green liquor"—a water
solution of sodium sulfide and sodium carbonate.  The green
liquor is then sent to the causticizing department for fur-
ther processing.  Weak wash is used as the dissolving liq-
uid in the smelt tank.  Weak wash is the liquid stream that
results from washing the lime mud.

The recovery furnace in which the smelt is formed was man-
ufactured by the Babcock and Wilcox Company.  This furnace
is designed to operate at an equivalent pulp production of
318 air dried metric tons (350 air dried tons) per day, but
it is presently operating around 363 to 408 air dried metric
tons (400 to 450 air dried tons) tons per day.  Hot black
liquor is sprayed into the furnace through a nozzle near
the furnace bottom  Occasionally, when extra heat is needed
or when the black liquor supply is temporarily interrupted,
natural gas or oil is burned.

The smelt dissolving system consists of a smelt spout, a
dissolving tank, agitators, circulating pumps, and a system
of pumps and piping for transferring the green liquor to the
causticizing department.  The smelt dissolving tank is nor-
mally supplied with a closed top, a vent pipe and steel
housing which enclose the smelt spouts projecting from the
front of the furnace hearth.
                           8

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A smelt spout is basically a water cooled trough.   It is
necessary to disperse or otherwise break up the stream of
smelt before it hits the surface of the liquor in  the tank.
This is accomplished by discharging a heavy stream of re-
circulated green liquor into the stream of molten  smelt
through nozzles located behind and slightly below  the smelt
spout.

Breaking up the smelt stream before it hits the liquor sur-
face in the tank prevents serious explosions which might be
caused by the reaction between the hot smelt, consisting
primarily of sodium sulfide and sodium carbonate,  and the
green liquor in which it is to be dissolved.  In effect,
there is a continual series of small explosions taking place
at the contact point of the molten smelt and the recircu-
lated green liquor.  This contact with the hot smelt thor-
oughly agitates the receiving water, and causes the for-
mation of large amounts of steam.  The steam is vented to
the atmosphere through a scrubber to remove particulates.
The smelt dissolving tank and scrubber are shown in Figure
2.

C.  Air Pollution Control System

The particulate emissions from the smelt tank are  controlled
by a packed tower scrubber.  This scrubber is designed to
handle 50,900 m3/sec (30,000 acfm).  The scrubber  is a 2.4
meter (8 foot) diameter steel tank 6.7 meters (22  feet)
high containing a scrubbing section in the bottom  packed
with 7.6 centimeter (3 inch) polypropylene intalox saddles,
and an entrainment separator (demister) in the top packed
with 5.1 centimeter (2 inch) polypropylene intalox saddles.
Between sections weak wash is sprayed downward .through a
distributor.to contact the gases which are drawn up through

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                            •Sampling ports
    Stack damper
   (normally closed)
    Smelt
(from recovery
   furnace)

 Green liquor
(to causticizing)
                     Stack
                                                     Entrainment
                                                      separator
                                                        Weak wash
    JA
Smelt dissolving tank
        Figure  2.  Smelt Dissolving Tank  and Scrubber
                 at the  Weyerhaeuser Mill  at
                     Everett,  Washington
                             10

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the packing by an induced draft fan.  One stream of water
leaves the scrubber.  A portion of this stream is bled off•
and drained to the smelt dissolving tank.  The rest of the
water is recycled and blended with the incoming makeup water
(weak wash).

PROCESS OPERATION

A.   General

The purpose of the tests was to measure emission levels
during normal mill operation.  Process conditions were
carefully observed, and testing was done only when the test
facility appeared to be operating normally.

During the tests, important process conditions were monitored
and recorded on data sheets.  Readings were taken about once
every half-hour.  These data, and a key to the entries, are
given in Appendix B and summarized b'elow.

B.   Smelt Dissolving Tank - Recovery Furnace

As far as can be determined from the process data (Appendix
B) and conversations with the operators, the equipment
operated normally during the tests.  The observed ranges of
major operating conditions during the tests are summarized
in Table 2.  Black liquor flow rate varied between 606 and
772 liters (160 and 204 gallons) per minute; the normal rate
is approximately 720 liters (190 gallons) per minute.  The
solids contents in the black liquor during these tests
range between 59.4 and 64.4$.

The recovery furnace operation was steady throughout the
tests.  The black liquor flow rate did change, however,
                           11

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                                  Table 2

        Summary  of  the Recovery Furnace and Packed Tower Process Data
                                              .Range during test
Operation
condition
Black liquor
feed rate
Black liquor
solids
content
Steam
production
Units
1pm
gpm
%
1000 kg/hr
1000 Ib/hr
#1
757-776
200-205
59.4-61.8
57-64
. 126-141
#2
606
160
60.6-62.6
64-68
140-150
#3
719
190
60.2-62.0
64-68
140-150
#4
606-719
160-190
60.6-62.2
57-64
125-140
#5
704-731
186-193
60.8-62.8
64-67
142-148
#6 '
712-719
188-190
61.0-64.4
64
. 140-142
Total recir-
 culation
 rate to
 packed tower

Makeup water
 to packed
 tower
1pm    1018-1136 1124-1143 1113-H54 1090-1168 1101-1136 1113-1136
gpm     269-300   297-302   294-305   288-308   291-300   294-300
1pm
gpm
303
 80
299
 79
299
 79
299
 79
299-303
 79-80
303
 80

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toward the end of Test No. 4.  A larger size nozzle was sub-
stituted so that a greater black liquor flow could be
accommondated.  The changeover only required about one min-
ute and, according to the operators, did not interrupt the
smelt flow to the smelt dissolving tank.  Once the nozzle
was changed the black liquor flow and other furnace param-
eters were steady.

During the last test (No. 6) there was a problem with the
ash return system from the furnace's precipitator.  The ash
is dissolved and ducted to the black liquor system prior to
the furnace.  This duct became plugged and had to be washed
out, with the result that only water entered the black liq-
uor system and diluted the black liquor.  This was. indicated
by the reduced black liquor density as recorded by the meter
in the control room.

However, according to the operators, this did not have an
affect on the total solids flow to the recovery furnace .
since they were adding extra salt cake makeup to compensate
for the loss in ash normally returned to the black liquor
system.  Analyses of the black liquor during this period
indicated solids contents of 6l and 64.4$.

C.   Air Pollution Control System

The total liquid recirculation flow rate to the scrubber's
sprays ranged between 1018 and 1166 liters (269 and 308
gallons) per minute during the tests.

The scrubber bypass damper was closed throughout the testing,
The damper did open slightly several times because of large
eruptions in the smelt dissolving tank.  These eruptions are
typical of smelt dissolving operation, and cause a buildup
                           13

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 of pressure in the system.   The bypass damper is designed to
 open when necessary to relieve the pressure.   These openings,
 however,  lasted only a few  seconds.

 The gases from the black liquor oxidation (BLO)  system at
 this mill are vented to the smelt dissolving  tank stack.
 This BLO  system was shutdown during our testing, however, so
 that the  BLO gases would not dilute the controlled emissions
 from the  smelt dissolving tank.  The BLO gases are normally
 added between the packed tower scrubber and the  outlet sam-
 pling location.

 D.   Equivalent Pulp Production Rates

 The operations of the smelt dissolving tank and  recovery
 furnace are quantitatively  related to the pulp production
 rate in the digesters.  As  a result, pollutant emission
 rate can  be expressed on the basis of equivalent pulp pro-
 duction,  as shown below:
/             \    /             \  /Equivalent  pulp\
(Emission  rate,] =  (Emission  rate,].J production  rate]   (1)
Ikg/ton pulp   I    \    kg/hr .   7  V     tons/hr    /

 To use Equation 1, the equivalent pulp production was cal-
 culated from the black liquor charged during  the tests, as
 shown below:
 Equivalent pulp
   production,
      M. tons
Black
liquor
charged,
liters
Pulp-to-liquor ratio
  at avg. % solids
    M tons/liter
 % Solids
(test avg.)
 % Solids
(base avg.)
 The  last  term  in  Equation  2  corrects  for  the  actual  percent
 solids  (in  the black  liquor  charged)  compared to  the average
 percent solids on which  the  pulp-to-liquor  ratio  is  based.
(2)

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The pulp-to-liquor ratio in the above equation was determine-
from mill records for the month of September 1973.  The total
pulp production during this time was 10,626 unbleached air
dried metric tons (11.713 tons).  Flow meter readings showed
that 26,925,400 liters (7,113,700 gallons) of black liquor
were charged during the same period.  By division, the pulp-
to liquor ratio was found to be 0.0004 M ton per liter
(0.00165 ton per gallon).

The average solids content of the black liquor charged during
the same time period (base average) was determined from the
furnace operator's two-hourly records of solids content.  The
average of all the readings was found to be 61.4$.
Substitution of the above determined values into Equation 2
gives:
Equivalent pulp
  production,
     M tons
Black liquor
.  charged,
  liters
    0.000-4
M tons/liter
"% Solids
(test avg.)
   617T
(3)
Equation 3 was used to calculate the equivalant pulp pro-
duction rate during each test on the smelt dissolving tank.
The calculations are summarized in Table 3-
In summary, emission rates in units of kg per metric ton
(pounds per ton) of pulp are calculated from Equation 1.
Equivalent pulp production rates to use in this equation are
also given in Table 3.
                           15

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                                                   Table  3
                      Summary  of Calculations  of Equivalent Pulp Production Rate
CT\
Date-1973
Oct.
Oct.
Oct.
Oct.
Oct.
10
10
11
12
12
Average black liquor
flow rate during test,
1pm. (gpm)
•606
719
666
715
715
(160)
(190)
(176)
(189)
(189)
Test' Time, Avg. %
mln Solids
220
220
220
220
220
61.7
61.1
62.2
61.8
62.7
Black liquor
charged
liters
x 10s (gallons)
1.33
1.58
1.17
1.57
1.57
(35,
(11,
(38,
(11,
(11,
200)
800)
720)
580)
580)
Equivalent
pulp
production
M ton (tons)
52.5
62.2
58.2
62.6
63.6
(57.9)
(68.6)
(61.2)
(69.0)
(70.1)
Equivalent pulp^ '
production rate,
M ton/hr (tons/hr)
11.3
17.0
15.9
17.1
17.3
(15.8)
(18.7)
(17.5)
(18.8)
(19.1)
         Calculated from Equation 2.

         ^Calculated by dividing equivalent pulp production by test time.

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              IV.  LOCATION OP SAMPLING POINTS

INLET TO SCRUBBER

The ports for the scrubber inlet sampling were located in
the original vertical stack at a distance of 4.17 m (164 in.)
from the smelt tank outlet and 0.97 m (31 in.) from the
junction of the scrubber inlet pipe and original stack.
A damper was located in the stack downstream from the
scrubber take-off line and could be opened if necessary to
bypass the scrubber.  The ports in the 1.37 m (54 in.)
stack were 5.1 cm (2 in.) diameter flanged half unions
covered with a blank flange.

OUTLET OF SCRUBBER

The scrubber outlet sampling location was in the original
1.37 m (54 in.) diameter stack at a point 3-73 m (147 in.)
from the junction of the stack and scrubber fan outlet line
and 1.73 m (68 in.) from the stack outlet.  This was the
center line location of one port, and the other port was
7.6 cm (3 in.) higher or 1.65 m (65 in.) from the atmospheric
outlet.  Ports were 10.2 cm (4 in.) ID flanged half unions
with a blank flange for closing.  The critical dimension
in terms of diameters was 2.72 diameters downstream from
the nearest upstream disturbance (the fan outlet).  The
dimensions required a 44 point traverse (22 points per
direction).
                          17

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A diagram of the total scrubber system showing the location
of the sampling ports is given in Figure 3.  Figure ^ shows
the location of the traverse points at both the inlet and
outlet ducts.
                          18

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t
LOCATION "A" 65"
1

r







— o (






."• "«^.
t
68"


1 PORTS SUITABLE FOR SAMPLING
~y~ TWO 4" PORTS @90°
45"
t ROOF
8' 6"
1 ,
•^ 	

f
— 	




\
-^ FAN
        LOCATION  "B"
                          DAMPER
PORTS 2" I.D.

     O    C




-— 54"

     ^
TO SMELT TANK
                                        12'
                             -SCRUBBER
                                              FLOOR
Figure  3.   Inlet  and Outlet  of Weyerhaeuser Company Scrubber

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                •25  ,
                  5.625
                      7.125
                        8.625
                                    21.5
                                     32.5
                                   36.5
                                 39.25
                              41.5
                            43.5
                         45.25
                      46.875
           52.250
Figure
Traverse  Point Locations
     20

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            V.  SAMPLING AND ANALYTICAL PROCEDURES

SAMPLING PROCEDURES

The outlet of the scrubber was sampled generally in accord-
ance with Federal Register methods.   Some exceptions to
the methods are listed below.

1.  The required number of traverse  points for this
    sampling location was 44 according to Method 1.
    However, when these were calculated, the 4 points
    nearest the wall were within 1 inch.  The calcul-
    ation for 48 points was used and the 4 extreme
    points omitted resulting in a complete 44 point
    traverse.

2.  Method 4 and the wet bulb-dry bulb moisture
    technique were used to determine initial moisture
    content.

3.  The nomograph calculations were  changed during the
    Method 5 runs to compensate for the change in
    moisture content as the stack gas temperature
    changed.  Also, due to the high moisture content
    of the stack gas, the excess water in the impingers
    was removed and the silica gel replaced during the
    port change of each run.
                          21

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4.  Method 5 procedures were modified to collect "back
    half" samples as well as the standard filter and
    probe samples as described in the section below.

ANALYTICAL PROCEDURES

Analytical procedures for the Method 5 samples followed
the Federal Register guidelines, with one exception.  Con-
tainer No. 3 as indicated in the method contains water from
the impingers and washing of,the glassware of the train.
The solution was extracted with chloroform and ether, and
then the extracted portion was dried to constant weight,
as specified.  In addition, the water remaining after ex-
traction was evaporated to dryness at 100°C to constant
weight.1  Both weights were included in the total mass of
particulate.  Sample weight from the Method 5 samples were
reported as "front half" (probe washings and filter col-
lection weights) and "total" (front half plus water, chloro-
form-ether extract and impinger acetone washing weights).
1See "Specifications for Incinerator Testing at Federal
 Facilities," U.S. Department of Health, Education, and
 Welfare publication, October 1967, page 31.
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