United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park NC 27711
Research and Development
EPA/600/S7-87/006 May 1987
v>EPA Project Summary
Kraft Pulp Industry Particulate
Emissions: Source Category
Report
Henry Modetz and Michael Murtiff
The objective of this study was to de-
velop particulate emission factors
based on cutoff size for inhalable parti-
cles for the kraft pulp industry. After a
review of available information charac-
terizing particulate emissions from
kraft pulp mills, the data were summa-
rized and rated in terms of reliability.
Size specific emission factors were de-
veloped from these data for the major
processes used in the manufacture of
kraft pulp. A detailed process descrip-
tion was presented with emphasis on
factors affecting the generation of
emissions. A replacement for Section
10.1 (Chemical Wood Pulping) of EPA
report AP-42, A Compilation of Air Pol-
lutant Emissions Factors, was pre-
pared, containing the size specific emis-
sion factors developed during this
program.
This Project Summary was devel-
oped by EPA's Air and Energy Engineer-
ing Research Laboratory, Research Tri-
angle Park, NC, to announce key
findings of the research project that is
fully documented in a separate report
of the same title (see Project Report
ordering information at back).
Introduction
The purpose of this program was to
summarize the best available informa-
tion on emissions of inhalable particu-
late matter in the kraft pulp industry.
The main objective of the program was
to develop reliable size-specific emis-
sion factors for the various processes
used in the production of kraft pulp.
Both uncontrolled and controlled emis-
sion factors are presented in the report.
The uncontrolled factors represent
emissions which would result if the par-
ticulate control device (baghouse,
scrubber, etc.) were bypassed, and the
controlled factors represent emissions
emanating from a particular type of con-
trol system. The size-specific emission
factors are generally based on the re-
sults of simultaneous sampling at the
inlet and outlet of the control device(s),
utilizing a variety of particle sizing tech-
niques. Other objectives of this pro-
gram were to present current informa-
tion on the kraft pulp industry as well as
prepare a replacement for Section 10.1
in EPA report AP-42, "A Compilation of
Air Pollutant Emissions Factors."
The above objectives were met by a
thorough literature search which in-
cluded:
• Data from the inhalable particulate
characterization program,
• Fine Particle Emissions Inventory
System (FPEIS),
• AP-42 background file at EPA's Of-
fice of Air Quality Planning and
Standards (OAQPS),
• State and local air pollution control
agencies, and
• Various industry sources (e.g., Na-
tional Council of the Paper Industry
for Air and Stream Improvement
and Technical Association of the
Pulp and Paper Industry).
The emission data contained in the
reference documents were reviewed,
analyzed, summarized, and ranked ac-
cording to the criteria established by
OAQPS as published in the EPA report,
"Technical Procedures for Developing
AP-42 Emission Factors and Preparing
AP-42 Sections," April 1980. After rank-
ing the data, emission factors were cal-
culated using the highest quality data
available. The quality of the data used to
develop each emission factor is indi-
cated by the emission factor rating.
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Process control system operating
data as well as general industry infor-
mation were also obtained and summa-
rized as general background informa-
tion. It was not part of this program to
provide detailed engineering analyses,
product specifications, or a detailed
evaluation of trends in the industry.
Summary of Results
Paniculate emissions from the kraft
process occur largely from the recovery
furnace, the lime kiln, and the smelt dis-
solving tank. These emissions consist
mainly of sodium salts with some cal-
cium salts from the lime kiln. They are
caused mostly by carryover of solids
and sublimation and condensation of
the inorganic chemicals.
Paniculate control is provided on re-
covery furnaces in a variety of ways. In
mills with either a cyclonic scrubber or
cascade evaporator as the direct contact
evaporator, further control is necessary
(these devices are generally only 20 to
50 percent efficient for particulates).
Most often in these cases, an electro-
static precipitator is employed after the
direct contact evaporator for an overall
paniculate control efficiency of 85 to
s99 percent paniculate control. Auxil-
iary scrubbers may be included after the
precipitator or the venturi scrubber to
provide additional control of particu-
lates. Paniculate from lime kilns is gen-
erally controlled by scrubbers. Smelt
dissolving tanks are commonly con-
trolled by mesh pads, but they have
scrubbers when further control is
needed.
The total mass controlled and uncon-
trolled emission factors for kraft pulp
manufacturing are presented in Table 1.
The size-specific controlled and uncon-
trolled emission factors for recovery
boilers are presented in Tables 2 and 3.
The size-specific controlled and uncon-
trolled emission factors for lime kilns
are presented in Tables 4 and 5. The
size-specific controlled and uncon-
trolled emission factors for smelt dis-
solving tanks are presented in Tables 6
and 7.
Table 1. Emission Factors for Sulfite Pulping"
Emission Factor Rating: A
Sulfur dioxide
Paniculate
Source
Digester relief and blow tank
Brown stock washer
Multiple effect evaporator
Recovery boiler and direct
evaporator
Type of control
Untreated"
Untreated"
Untreated11
Untreated"
Venturi scrub-
bed
ESP
Auxiliary
scrubber
kg/Mg
—
—
—
90
24
1
7.5-7.5''
Ib/ton
—
—
—
780
48
2
3-75'
(S02)
kg/Mg
—
—
—
3.5
3.5
3.5
Ib/ton
—
—
—
7
7
7
Carbon
monoxide (CO)
kg/Mg
—
—
—
5.5
5.5
5.5
Ib/ton
—
—
—
77
77
77
Hydrogen
Sulfide
0.1 i
0.2*
0.2*
0.2*
0.5m
0.5m
0.07
—
—
—
0.75*
0.75*
0.75*
0.7m
0.7m
0.25
0.25
—
—
0.3*
0.3*
0.3*
0.2m
0.2m
0.5
0.5
"Factors expressed in unit weight of air dried unbleached pulp (ADP). RSH = Methyl mercaptan. RSR = Dimethyl sulfide. RSSR = Dimethyl
disulfide. ESP = Electrostatic precipitator.
blf noncondensable gases from these sources are vented to lime kiln, recovery furnace, or equivalent, the reduced sulfur compounds are
destroyed.
cApply with system using condensate as washing medium. When using fresh water, emissions are 0.05 (0.1).
dlncludes knotter vents, brownstock seal tanks, etc. When black liquor oxidation is included, emissions are 0.3 (0.6).
1'Apply when cyclonic scrubber or cascade evaporator is used for direct contact evaporation, with no further controls.
'Usually reduced by 50% with black liquor oxidation and can be cut 95 - 99% when oxidation is complete and recovery furnace is operated
optimally.
sApply when venturi scrubber is used for direct contact evaporation, with no further controls.
hUse 7.5 (15) when auxiliary scrubber follows venturi scrubber, and 7.5 (3) when it follows ESP.
'Apply when recovery furnace is operated optimally to control total reduced sulfur (TRS) compounds.
kUsually reduced to 0.07 g/kg (0.02 Ib/ton) ADP when water low in sulfides is used in smelt dissolving tank and associated scrubber.
mUsually reduced to 0.015 g/kg (0.03 Ib/ton) ADP with efficient mud washing, optimal kiln operation, and added caustjc in scrubbing water. With
only efficient mud washing and optimal process control, TRS compounds reduced to 0.04 g/kg (0.08 Ib/ton) A
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Table 2. Cumulative Particle Size Distribution and Size Specific Emission Factors for a
Recovery Boiler with a Direct Contact Evaporator and an ESP
Emission Factor Rating: C
Particle size
Cumulative mass %s Cumulative emission factor
stated size fkg/Mg of air dried pulp)
(p.m) Uncontrolled Controlled Uncontrolled Controlled
15
10
6
2.5
7.25
7.00
0.625
Total
95.0
93.5
92.2
83.5
56.5
45.3
26.5
100
—
68.2
53.8
40.5
34.2
22.2
100
86
84
83
75
51
41
24
90
—
—
0.7
0.5
0.4
0.3
0.2
1.0
Table 3. Cumulative Particle Size Distribution and Size Specific Emission Factors for a
Recovery Boiler without a Direct Contact Evaporator but with and ESP
Emission Factor Rating: C
Cumulative mass %s Cumulative emission factor
stated size (kg/Mg of air dried pulp)
Particle size — ——
Uncontrolled Controlled Uncontrolled Controlled
15
10
6
2.5
1.25
1.00
0.625
Total
—
—
—
78.0
40.0
30.0
17.0
100
78.8
74.8
71.9
67.3
51.3
42.4
29.6
100
—
—
—
90
46
35
20
115
0.8
0.7
0.7
0.6
0.5
0.4
0.3
1.0
Table 4. Cumulative Particle Size Distribution and Size Specific Emission Factors for a Lime
Kiln with a Venturi Scrubber
Emission Factor Rating: C
Particle size
(v-m)
15
10
6
2.5
1.25
1.00
0.625
Total
Cumulative mass %s
stated size
Uncontrolled
27.7
16.8
13.4
10.5
8.2
7.1
3.9
100
Controlled
98.9
98.3
98.2
96.0
85.0
78.9
54.3
100
Cumulative emission factor
(kg/Mg of air dried pulp)
Uncontrolled
7.8
4.7
3.8
2.9
2.3
2.0
1.1
28.0
Controlled
0.24
0.24
0.24
0.24
0.21
0.20
0.14
0.25
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Table 5. Cumulative Particle Size Distribution and Sige Specific Emission Factors for a Lime
Kiln with an ESP
Emission Factor Rating: C
Cumulative mass %£ Cumulative emission factor
stated size
(v-m)
15
10
6
2.5
1.25
7.00
0.625
Total
Uncontrolled
27.7
16.8
13.4
10.5
8.2
7.1
3.9
100
Controlled
91.2
88.5
86.5
83.0
70.2
62.9
46.9
100
Uncontrolled
7.8
4.7
3.8
2.9
2.3
2.0
1.1
28.0
Controlled
0.23
0.22
0.22
0.21
0.18
0.16
0.12
0.25
Table 6. Cumulative Particle Size Distribution and Size Specific Emission Factors for a Smelt
Dissolving Tank with a Packed Tower
Emission Factor Rating: C
Cumulative mass %•& Cumulative emission factor
stated size
(\t.m)
15
10
6
2.5
1.25
1.00
0.625
Total
Uncontrolled
90.0
88.5
87.0
73.0
47.5
40.0
25.5
100
Controlled
95.3
95.3
94.3
85.2
63.8
54.2
34.2
100
Uncontrolled
3.2
3.1
3.0
2.6
1.7
1.4
0.9
3.5
Controlled
0.48
0.48
0.47
0.43
0.32
0.27
0.17
0.50
Table 7. Cumulative Particle Size Distribution and Size Specific Emission Factors for a Smelt
Dissolving Tank with a Venturi Scrubber
Emission Factor Rating: C
Cumulative mass %•& Cumulative emission factor
stated size (kg/Mg of air dried pulp)
Particle size
Uncontrolled Controlled Uncontrolled Controlled
15
10
6
2.5
1.25
1.00
0.625
Total
90.0
88.5
87.0
73.0
47.5
54.0
25.5
100
89.9
89.5
88.4
81.3
63.5
54.7
38.7
100
3.2
3.1
3.0
2.6
1.7
1.4
0.9
3.5
0.09
0.09
0.09
0.08
0.06
0.06
0.04
0.09
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H. Modetz and M. Murtiff are with Acurex Corporation, Mountain View, CA
94039.
Dale L. Harmon is the EPA Project Officer (see below).
The complete report, entitled "Kraft Pulp Industry Paniculate Emissions: Source
Category Report," (Order No. PB 87-169 603/AS; Cost: $18.95, subject to
change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Project Officer can be contacted at:
Air and Energy Engineering Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection
Agency
Center for f nvironmental Research
Information
Cincinnati OH 45268
Official Business
Penalty for Private Use $300
EPA/600/S7-87/006
0000329 PS
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