EPA PROJECT REPORT NO. 74-LIM-6
       AIR  POLLUTION
       EMISSION  TEST
                OOW CHEMICAL

                freeport, Texas
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

-------
                       A STUDY OF GASEOUS AND PARTICULATE
                         EMISSIONS FROM LIME KILNS AT
                       DOW CHEMICAL CORPORATIONS'S PLANT B
                               FREEPORT, TEXAS
                                 May, 1974
environmental science and engineering, inc.               ,'
                                    EPA-RTF LIBRARY

-------
         A STUDY OF GASEOUS AND PARTICULATE

            EMISSIONS FROM LIME KILNS AT

             DOW CHEMICAL CORPORATION

                      PLANT B

                  FREEPORT, TEXAS
                     May, 1974
             PREPARED AND SUBMITTED BY:
     ENVIRONMENTAL SCIENCE AND ENGINEERING, INC.
               POST OFFICE BOX 13454
             GAINESVILLE, FLORIDA  32604
                  PN  73 Oil  042
                   PREPARED FOR:

        U.S. ENVIRONMENTAL PROTECTION AGENCY
           EMISSIONS MEASUREMENT  BRANCH
        RESEARCH TRIANGLE PARK,  NORTH CAROLINA
environmental science and engineering, inc.

-------
                    TABLE OF CONTENTS

                                                   Page Number

     List of  Tables                                      ii
     List of  Figures                                     iii
1.0  Introduction                                      .   1
2.0  Summary  and Discussion of Results                     3
3.0  Process  Description and Operation                     9
4.0  Location of Sampling Points                         15
5.0  Sampling and Analytical Procedures                   15
     Appendices
          A - Calculated Emissions  Data
          B - Field Data
          C - Analytical Procedures and Sample Calculations
          D - Lab Report
          E - Test Log
          F - Notes on Plant Operation
          G - Project Participants
                              -i-
     environmental science and engineering, inc.

-------
                        LIST OF TABLES
                                                Page Number
Table 2.1  Participate  Data Summary -  English         4
Table 2.2  Particulate  Data Summary -  Metric          5
Table 2.3  Gas Data Summary                          6
Table 3.1  Summary of Operating Variables             14
                             -11-
       environmental science and engineering, inc.

-------
                        LIST OF FIGURES

                                            Page Number


Figure 3.1  Precipitator Plan and Elevation        11

Figure 3.2  Stack Elevations                      12
                             -iii-
      environmental science and engineering, inc.

-------
1.0  INTRODUCTION
     A part of the  Environmental Protection Agency's ongoing work in pollu-
     tion abatement is  concerned with setting performance standards for new
     and substantially  modified stationary sources.  One source under con-
     sideration at  present  is rotary kilns used to calcine lime.  Dow Chemical
     Corporation operates a large chemical complex in Freeport, Texas which
     uses slaked lime in recovering magnesium from seawater and various
     other operations.
     There are three rotary kilns used to calcine dolomite (CaCO^ • MgCO ).
     The plant is capable of operating one, two or all three kilns simultan-
     eously.   The kilns are serviced by electrostatic precipitators (ESP's)
     for the  control of particulate emissions.  The gas stream from the
    operating kilns i s combined prior to the ESP's and then split and ducted
    through two ESP's and vented to the atmosphere through two stacks,
    one for each ESP.
    During the week of  April 29, 1974, Environmental Science and Engineering,
    Inc. (ESE) conducted three  series of tests on the two outlet stacks
    under contract  for  the  EPA.  During the testing period two of the kilns
    were operating  simultaneously.  Each stack was monitored for particulate
    matter, using  EPA method 5; opacity, using a modified version of EPA
    method 9; C02  and Og, using a modified version of EPA method 3; and CO,
    using EPA method 10.  In addition, S02 concentrations were measured on
    the north stack using EPA method 6 and NOX concentrations were measured
    on the south stack  using EPA method 7.
                                     -1-  .
          environmental science and engineering, inc.

-------
Another provision of the  tests was to conduct comparison tests  for

participate matter at a single location in  the stack using an in-stack

filter and an EPA-5 train.  No valid comparison data were obtained due

to equinment difficulties.
                               -2- .
     environmental science and engineering, inc.

-------
2.0  SUMMARY AND DISCUSSION OF  RESULTS
2.1  Participate matter,  Orsat, CO, S0_, NOV and opacity data are summarized
                                     £.    A
     in Tables  2.1 - 2.3.

     The total  average  particulate emission rate was 4.9kg/hr. (10.8
     Ibs/hr.) for the two stacks combined.  However, this value is probably
     somewhat high  as  the first test on the north stack indicated 5.7 kg/hr.
     (12.6 Ibs/hr.)  alone.  The average for runs 2 and 3 was 3.6 kg/hr.
     (7.9 Ibs/hr.)  for  the two stacks combined, which is substantially lower.
     It is not  known why  the first run on the north stack indicated such a
     high emission  rate.  Some error may have been introduced because the
     person manipulating  the probe misunderstood where the probe markings
     were to be located;  instead of locating the marking at the outside  of
     the pipe nipple, he  positioned it at the inside stack wall on the first
     run only.   This means that each point sampled was displaced from the
     equal  area center  by approximately 4 inches.  It seems unlikely that
     this would introduce a very large error, however., it is possible that
     the probe  tip  came so close to the far stack wall that it contaminated
     the sample with particulate off the stack wall.

     Laboratory analysis  of the particulate samples showed a large amount
     of variability  in  the weight fraction caught in the various parts of
     the sampling train (probe, filter, etc.).  The average for all of the
     runs was as follows:  Probe - 20.5%, Filter - 32%, Back Half Water  -
     29.5%, Back Half Acetone - 18%.  This means that only 53% of the total
     catch was  caught in  the probe and filter (front half), the remaining
     portion being  in the impingers.
                                    -3-  '
           environmental science and engineering, inc.

-------
                                 Table 2.1   Particulate Data  Summary  (English)
RUN NUMBER
DATE
STACK DESIGNATION
Volume of Gas Sampled, DSCF^
Percent Moisture By Volume
Average Stack Temperature, °F
Stack Volumetric Flow Rate, DSCFM
Stack Volumetric Flow Rate, ACFM '
Percent Isokinetlc ,_.
Process Weight Rate, Ton/Hr ^'
1
1
April 30, 1974
NORTH SOUTH
43.39
18.5
373
49.144
93.559
128
20.3
99.62
17.1
449
47,834
97,870
119
20.3
2
May 2
NORTH
131.33
17.6
361
45.911
85,521
103
20.0

, 1974
SOUTH
131.66
17.9
412
42,945
85,190
110
20.0

May 3
NORTH
133.72
18.2
366
46,318
87,951
104
20.3
3
, 1974
SOUTH
136.15
18.6
406
45,693
91,500
no
20.3


Averages
NORTH SOUTH
102.81
18.1
367
47,124
89,010
111
20.2
122.48
17.9
422
45,490
91 ,520
113
20.2
PARTICIPATES - PROBE AND FILTER
Gr/DSCF <3)
Gr/ACF
Lb/Hr
Lb/Ton Feed
46.7
0.0166
0.0087
7.00
0.344
39.5
0.0061
0.0029
2.51
0.124
30.6
0.0036
0.0019
1.42
0.071
21.9
0.0025
0.0013
0.95
0.048
51.2
0.0059
0.0031
2.35
0.116
49.5
0.0056
0.0028
2.20
0.108
42.8
 0.0087
 0.0046
 3.59
 0.177
37.0
 0.0047
 0.0023
 1.89
 0.093
PARTICULATES. TOTAL

Mg
Gr/DSCF
Gr/ACF
Lb/Hr
Lb/Ton Feed
Percent Implnger Catch
84.2
0.0299
0.0157
12.62
0.62
44.5
63.9
0.0099
0.0047
4.06
0.20
38.2
49.4
0.0058
0.0031
2.28
0.114
38.1
126.4
0.0147
0.0074
5.45
0.272
82.7
71.2
0.0082
0.0043
3.26
0.161
28.1
106.7
0.012
0.006
4.74
0.233
53.6
68.3
0.0146
0.0077
6.05
0.298
36.9
99.0
0.0122
0.0060
4.75
0.235
58.2
     Dry  standard cubic feet  at 70°F and 29.92  Inches Hg.
     These values are averages for the kilns (see Table 3.1) I.e.  total feed rate for  run #1 was 40.6 ton  per hour.
     Grains per DSCF.

-------
                                Table  2.2  Particulate  Data  Summary (Metric)
RUN NUMBER
DATE
STACK DESIGNATION
Volume of Gas Sampled, DSCM^'
Percent Moisture by Volume
Average Stack Temperature, °C
Stack Volumetric Flow Rate, DSCMM
Stack Volumetric Flow Rate. ACMM
Percent Isokinetic /?\
Feed Rate, M-Ton/Hrv ;
1
April 30,
NORTH
1.23
18.5
189
1392
2650
128
18.4

1975
SOUTH
2.82
17.1
232
1355
2772
119
18.4
2
May 2,
NORTH
3.72
17.6
183
1300
2422
103
18.2

1974
SOUTH
3.73
17.9
211
1216
2413
110
18.2
3
May 3.
NORTH
3.79
18.2
186
1312
2491
104
18.4

1974
SOUTH
3.86
18.6
208
1294
2591
no
18.4

Averages
NORTH SOUTH
2.91 3.47
18.1 17.9
186 217
1334 1288
2521 2592
111 113
18.3 18.3
PARTICULATES  -  PROBE AND FILTER

Mg
Mg/DSCM
Mg/ACM
Kg/Hr
Kg/M-Ton Feed
46.7
38.01
19.96
15.4
 0.84
39.5
14.00
 6.84
 5.52
 0.30
30.6
 8.23
 4.42
 3.12
 0.17
 21.9
  5.87
  2.96
  2.09
  0.11
51.2
13.52
 7.11
 5.17
 0.28
 49.5
 12.84
  6.41
  4.84
  0.26
42.8
19.92
10.50
 7.90
 0.43
37.0
10.90
 5.40
 4.15
 0.23
PARTICULATES - TOTAL

Mg
Mg/DSCM
Mg/ACM
Kg/Hr
Kg/M-Ton Feed
Percent Impinger Catch
84.2
68.53
35.99
27.76
 1.51
44.5
63.9
22.65
11.07
 8.93
 0.48
38.2
49.4
13.28
 7.13
 5.02
 0.28
38.1
126.4
 33.90
 17.08
 11.99
 0.66
 82.7
71.2
18.80
 9.90
 7.17
 0.39
28.1
106.7
 27.67
 13.81
 10.43
  0.57
 58.2
68.3
33.54
17.67
13.32
 0.73
36.9
99.0
28.07
13.99
10.45
 0.57
58.2
(1)  Dry standard  cubic meter at 21°C and 29.92  Inches Hg
(2)  Metric tons per hour (2200 Ibs - 1  M-Ton)

-------
                                                   Table  2.3  Gas  Data Summary
CT>
Run
1

2

3

Location
North
South
North
South
North
South
Flow
SCMMD
1392
1355
1300
1216
1312
1294
Orsat CO Visible
Data PPMD Opacity
% C02 % 02 PPMD NOX PPM S02 1234
8.7 12.2 63 0 00
10.0 11.1 20 129 00
9.7 11.3 27 00 <5^'
10.4 9.7 34 96 00
8.1 10.8 250 0- O^2^ <5^
10.0 9.8 260 96 0(2* <5(
                       Several readings  of 5 and 10




                       Several readings  of 5

-------
After the first run, the Orsat was  found  to  be  in error when checked
against ambient air.  Since it rained all  day Wednesday, time was spent
calibrating a portable gas chromatograph  to  measure CO  and 0 .  When
the integrated gas samples from the first day's  testing were analyzed
Wednesday afternoon, it appeared that the results were in error, i.e., the
percent CO  seemed low and the percent 0_ high.  However, when comparable
results were obtained from test 2 on Thursday,  it seemed to indicate
that there was possibly a leak, either in the integrated sampler or in
the duct work.

To find out where the leak was, a direct  sample  was taken from the stacks
on Thursday evening; the results were the same  as those obtained from
the bag sample.   On close examination it  was discovered that ambient
air was drawn into the system prior to the ESP's.  The major places where
this occurred were at the kiln bearing seals and the openings (approxi-
mately 20 x 40 inches) where  the feed rock is dropped from conveyor belts
into the kiln.  These locations are on the negative side of the fan and,
                                             o
hence,draw ambient air into the system.

The concentration of CO as measured by NDIR  from injections taken from
the integrated bag samples varied more than  one  would expect since the
gases in the ductwork should  have been thoroughly mixed.  The average
concentration for"all six runs was  109 ppmd.2 However, analysis of the
gases from the last day's runs indicated  250 and 260 ppmd as compared
to 63 and 20, 27 and 34 ppmd  from the first  two days.
'  Non-dispersive infrared
  Parts per million dry gas  volume
                                  -7-
      environmental science and engineering, inc.

-------
     Concentrations  of NO  were  129, 96, and 96 ppmd for the three runs.
                        /\
     Each run consisted of four  grab samples, the results of which are
     included in Appendix A.
     At no time was  any SC^ present in detectable amounts.   This was expected
     since the kilns were fired  with natural gas and the processed dolomite
     probably contained little,  if any, sulfur inclusions.

     Visible opacity was in general 0% with a few exceptions.  One observer
     (No. 4) indicated quite a few as less than 5% on the second and third
     tests.

2.2  COMPARATIVE TESTING
     Difficulties were experienced in getting a good comparative sample.
     No valid comparative data were obtained due to equipment malfunctions.
     EPA supplied some of the equipment to avoid potential  problems in inter-
     facing  the special  probe assembly with other parts of the sampling train.
     The difficulties were caused primarily by a leak in the EPA's meter
     box.  Once this was fixed it was found that the meter was still mal-
     functioning.  Finally, the  meter stopped working during the second
     comparative test.   Since the meter was not operating properly, it would
     be meaningless  to calculate a grain loading based on the indicated
     gas volume.  "However, a copy of the comparative data  can "be  found in
     the appendices.
                                        -8-
           environmental science and engineering, inc.

-------
3.0  PROCESS DESCRIPTION AND OPERATION
     Limestone  consists primarily of calcium carbonate or combinations of
     calcium and  magnesium carbonate with varying amounts of impurities.
     Lime is a  calcined or burned form of limestone, commonly divided into
     two  basic  products—quicklime and hydrated lime.   Calcination  expels  carbon
     dioxide from the raw limestone, leaving calcium oxide (quicklime).   With
     the  addition of water  (slaking), calcium hydroxide  (hydrated  lime)  is forme'd.

     In standard chemical  notation,  the reations are:
         Calcination    CaC03   Heat -   CaO-+ C021
         Hydration      CaO + H20	=>• Ca(OH)2
     The basic  processes  in production are:  1) quarrying the limestone  raw
     material,  2)  preparing the limestone for kilns by crushing and sizing,
     3)  calcining  the  limestone, and 4) optionally processing the quicklime
     further  by additional crushing and sizing and then hydration.   The
     majority of lime  is  produced in rotary kilns which can be fired by
     coal,  oil,  or gas.   Rotary kilns have the advantages of high production
     per man-hour  and  a uniform product, but require higher capital invest-
     ment and have higher unit fuel costs than most vertical kilns.

     The Dow  Chemical  plant has three rotary lime kilns operating on Texas
     dolomitic  limestone.  The product quicklime is slaked to the hydrate
     (milk  of lime) and used to precipitate magnesium hydroxide from seawater.
     Most of  the purified magnesium hydroxide is reacted with hydrogen chlor-
     ide to make magnesium chloride which is converted to magnesium metal
     in  electrolytic cells.
                                 -9-
            environmental science ahd engineering, inc.

-------
There are three straight bore kilns, each 9 feet 6 inches by 265 feet,
with a design capacity of 250 tons per day each.  They "very seldom"
run all three kilns, usually two are on line.  The dolomite feed stone
is brought into the plant sized one half to three quarters inch or
three quartersto one and one half inches top size.   There is  no  stone
preheater.  The kilns are fired with natural  gas and the  product  quicklime
is cooled to 200-300°F with  satellite  coolers.   There  is  no quicklime
storage, as all  the product  is  fed into three  rotating  drum slakers where
the milk of lime is produced.

The three kilns  are provided with an electrostatic precipitator  manu-
factured by the Western Precipitation Division  of the Joy Manufacturing
Company.  The exit gas from the three kilns is  cooled to  500°F  by water
sprays and enters a common plenum.   From this plenum the  gas  is  dis-
tributed to the two chambers of the precipitator by manually  operated
guillotine dampers.  Each chamber has three fields, thirty-five  gas
passages, and a plate area of 35,280 square feet.   From data  which Dow
supplied, it can be calculated (if only two kilns  are in  operation) that
the design velocity is 2.0 feet per second and  the design residence time
is 10.5 seconds.   Following  the  precipitatbrs, the  stack  gases are
vented to the atmosphere  through 80 foot high stacks, one  servicing
each precipator.   The complete  layout -is illustrated  in Figures
3.1 and 3.2.
The dust collected from the precipitators  is presently wasted.  In
the future this dust may be granulated  and  returned to the kiln.
                                -10-
        environmental science and engineering, inc.

-------
          North
                                       Chambers
                                              Sample Pt.  "A"
                           ELEVATION
Figure 3.1.   Precipitator Plan  and Elevation.
                    -11-,

-------
                           8'
                               -*!
       80'
               10'
                    E
                26'
Ground //////
Sample
 Ports
                                           90° apart
                                                                   •o
                               ELECTROSTATIC PRECIPITATOR
                             Figure  3.2    Stack Elevations
                                          -12-

-------
Each chamber of the precipitator  has  nineteen rappers, and there is
one for each distribution plate.   The rappers operate in sequence, one
complete cycle requiring about twenty minutes.
The operation of the kilns and the electrostatic precipitator was moni-
tored during the tests;  process data  are summarized in Table 3.1.
It appears that the kilns operated normally throughout the test.  On
May 1 there was heavy rain all  day and no sampling was possible.  During
the 3 to 11 shift on that day, the  A field in the south precipitator
chamber'began arcing badly and was therefore removed from service and
grounded.   Plant personnel  thought that rain may have leaked into the
insulator on the top of  the precipitators.  On the morning of May 2,
the south A field was put back on  line and, although there was still
some arcing, it was not  serious enough to significantly affect the
efficiency of the precipitator.
On May 3, the south A field was arcing and the voltage  on  the  field was
down from 275 V (on May 2) to 250-255 V.   The south A field  was  there-
fore removed from service and grounded before testing began.   The  south
chamber, during the last day of testing,  was therefore  operating with
57% of its normal  plate area.  Even with  this reduced collecting surface,
there were no  significant visible  emissions.
                               -13-
       environmental science and engineering, inc.

-------
                           Table 3.1 Summary of Operating Variables.
Test No. and (Date)



Kiln No.
   1   (4/30)



2            3
   2  (5/2)



2            3
3  (5/3)
Stone Feed Rate (tons/hr)
Ray 0 Tube Temp. (°F)
Slip Ring Temp. (°F)
Feed End Temp. (°F)
Fan Temp. ("F)
Electrostatic Precipitator
A Field
Primary Current (amps)
Primary Voltage (volts)
B Field
Primary Current (amps)
Primary. Voltage (volts)
C Field
Primary Current (amps)
Primary Voltage (volts)
19.4 21.2
2174-2192 2192-2246
1472-1490 1418-1436
1156-1166 1256
500 536
Data
'136-140
260-275
185
230
152-155
205-210
19.0 21.0
2156-2210 2156-2174
1436-1460 1400-1436
1184-1202 1220-1229
500-518 527-536
135-137
250-283
183-184
232-235
151-153
200-204
18.9 21.7
2174-2210 2156-2210
1454-1490 1382-1400
1184-1202 1238-1256
518-536 536
135-137*
290-300*
182-185
235-240
151-153
202-205
*The south A field was grounded and not operating during the test.

-------
4.0  LOCATION OF SAMPLING POINTS
     As the sampling ports were located only 26 feet downstream from the pre-
     cipitator exit and 10 feet from  the  top of the stack, it was necessary
     to sample 22 points  on each  of two diameters through two ports 90° apart
     in each stack (total  of 44 points in each).  These points were selected
     according to method  1  of the Federal Register which locates each point
     at the center of equal  area  zones.   The exact location of these points
     is included in Appendix B.   As mentioned previously, for the first run
     on the north stack,  each point was inadvertently shifted 4 inches too
     far into the stack.   Due to  the  length of probe in the stack, the strain
     on the union of probe and heated box prevented several points near the
     far wall of both stacks from being sampled.

5.0  SAMPLING AND ANALYTICAL PROCEDURES
5.1  PARTICULATE SAMPLING
     Particulate samples  were obtained using the standard EPA method 5 train
     without a cyclone, following  the  procedures specified in the December
     21,  1971  Federal  Register.   In addition, .the impinger contents were
     obtained and analyzed  according  to the appropriate procedures specified
     in the proposed  Method  5  in  the  August 17, 1971  Federal  Register; except
     that,the organic extraction  was  not performed.
     Prior to the first run, a preliminary moisture run was made in order
     to obtain a moisture fraction for setting the nomograph.  Subsequently,
     for purposes of setting the  nomograph, the moisture fraction was assumed
     to be 18-19 percent as found from the first particulate runs.
                                    -15-
            environmental science and engineering, inc.

-------
     Gas temperatures were measured  before  and during each test with bimetallic
     dial thermometers accurate to ± 5°F.   These measurements were made at
     a single point in the stack instead  of at each sampling point.  There
     appeared to be very little temperature gradient across the stack,making
     a one point temperature sample  sufficient.
     In addition, before each run except the third run, a preliminary
     velocity traverse was made on one  diameter  of each stack for the pur-
     pose of balancing the flow rates.   If  necessary, damper, adjustments
     were made under the direction of the EPA project engineer.

     At the end of each run,  the particulate sampling trains were moved to
     a nearby room for clean-up.  The samples obtained were transferred to
                                                    D
     acid-washed glass storage containers with Teflon  seals for subsequent
     laboratory analysis.   A  description of the  analysis procedures is
     included in Appendix C.

5.2  S02 SAMPLING METHODS
     Since it was requested by the EPA  project officer that SO  sampling
     extend the full  period during which particulate samples were obtained,
     it was necessary to add  a dry impinger between the isopropanol  bubbler
     and first peroxide impinger to  trap any diluted isopropanol carryover
     to prevent sample contamination.   This was  the only deviation from
     method 6, as specified in the December 21,  1971  Federal Register.

5.3  N0v SAMPLING METHODS
       A
     Four NOX grab samples  were  taken,foil owing  Method 7 as specified in the
     December 21, 1971  Federal  Register during each particulate run  on the
                                      -16-
            environmental science and engineering, inc.

-------
     south stack;  the arithmetic mean  of these four samples is reported as the
     result for that run.   These samples were approximately equally spaced in time
     during the run  in order  to obtain a representative average.

5.4  INTEGRATED BAG  SAMPLES
     An integrated bag sample was obtained from each stack during the period
     of the particul ate runs,foil owing Method 3 as specified in the December
     21, 1971  Federal  Register.

     At the end of each run the bag's  contents were analyzed by NDIR for CO,
     and for COg and 0~ by  gas chromatography utilizing a thermal detector.
     A copy of the analytical procedures is  included in Appendix C along
     with the calibration procedure  for the  GC and sample calculations show-
     ing corrections for CO?  in the  CO concentrations, according to Method
     10 as specified in the March 8, 1974 Federal Register.

5.5  VISUAL SMOKE  OBSERVATIONS
     During the first particulate tests, two visual observers were assigned
     to read each  stack.  Due to manpower requirements, this number was re-
     duced to three  observers on the second  particulate test and two observers
     on the third.  Since the opacity  did not differ much from 0 at any time,
     it was possible to have  the observers double up and read both stacks
     simultaneously  for the last two tests.  The observers followed the
     guidelines set  forth in  Method  9}as specified in the December 21, 1971
     Federal Register.

5.6  COMPARATIVE TESTING
     Two probes were attached to a common pi tot tube which allowed isokinetic
     sampling at approximately the same point in the stack.  The in-stack
                                  -17-
             environmental science and engineering, inc.

-------
filter train differed from the method 5 train in  that an additional



in-stack  filter holder was placed directly behind the nozzle.  The re-



mainder of  the sampling equipment remained unchanged.  Equipment diffi-



culties prevented obtaining valid results.
                             -18-



      environmental science and engineering, inc.

-------