EPA-450/3-77-OOS
BACKGROUND DOCUMENT:
ACID SULFITE PULPING
by
Al Linero
Environmental Science and Engineering, Inc.
University Station
Gainesville, Florida 32604
Contract No. 68-02-1402
Task Order No. 14
EPA Project Officer: Thomas F. Lahre
Prepared for
ENVIRONMENTAL PROTECTION AGENCY
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
January 1977
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This report is issued by the Environmental Protection Agency to report
technical data of interest to a limited number of readers. Copies are
available free of charge to Federal employees, current contractors and
grantees, and nonprofit organizations - in limited quantities - from the
Library Services Office (MD-35), Research Triangle Park, North Carolina
27711; or, for a fee, from the National Technical Information Service,
5285 Port Royal Road, Springfield, Virginia 22161.
This report was furnished to the Environmental Protection Agency by
Environmental Science and Engineering, Inc., University Station, Gaines-
ville, Florida 32604, in fulfillment of Contract No. 68-02-1402, Task Order
No. 14. The contents of this report are reproduced herein as received
from Environmental Science and Engineering, Inc. The opinions, findings,
and conclusions expressed are those of the author and not necessarily
those of the Environmental Protection Agency. Mention of company or
product names is not to be considered as an endorsement by the Environ-
mental Protection Agency.
Publication No. EPA-450/3-77-005
11
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TABLE OF CONTENTS
1.0
2.0
2.1
2.2
2.3
2.3.1
2.3.2
2.3.3
2.3.4
3.0
3.1
3.2
3.3
3.4
4.0
4.1
4.2
4.3
4.4
GENERAL INFORMATION
PROCESS DESCRIPTION
Digestion
Washing and Knotting
Chemical Manufacture, Recovery and
Fortification
Calcium As Base
Ammonia As Base
Magnesium As Base
Sodium As Base
FACTORS AFFECTING EMISSIONS
Base Chemical Utilized
Level of Acidity
Digester Relief and Discharge Techniques
Level of Chemical and Heat Recovery
DEVELOPMENT OF ACID SULFITE PULPING EMISSION
FACTORS
Compilation of Data
Tabulation of Emission Factors
Method of Estimation of Emission Factors
Ranking of Emission Factors
Page Number
1
4
4
7
8
8
9
10
12
12
13
13
15
18
19
19
23
26
26
REFERENCES
APPENDIX
28
29
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1.0 GENERAL INFORMATION
The sulfite pulping industry primarily is characterized by the type of
base chemical used in conjunction with sulfurous acid to effect de-
lignification of gymnosperm woods. It further is characterized by the
level of acidity during the digestion operation and by the extent of
recovery of chemicals and waste heat.
During the first half of this century calcium was the base of choice
used with sulfurous acid. Recently, however, the popularity of magnesium
and ammonia as base chemicals has risen markedly with the result that
they have become the dominant sulfiting agents. Among the reasons for
the above trend is that chemical and heat recovery can be achieved more
economically through use of magnesium and ammonia than through use of
calcium. No small part is played by the restrictions placed upon plants
in order to reduce effluents discharged into rivers and lakes.
Table I1 presents 1975 data on pulp and paper capacities of mills in
the United States. In the United States, sulfite pulp comprises only
a minor share (6.2%) of the total pulp produced. Sulfite operations
primarily are centered in the states of Washington, Oregon, Wisconsin,
and Maine. The outlook for sulfite pulping in the immediate future
indicates slow growth.
From Table 21 it can be seen that at least one sulfite mill is being
replaced by a kraft mill. This is in accordance with the recent trend
towards the phasing out of calcium based sulfite mills.
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Table 1. United States Mill Capacities (tons/day)
DEFI- SEC-
STATES PAPER & SULFITE SULFATE SODA SEMI- GROUND- BRATED ONDARY OTHER
BOARD PULP* PULP* PULP CHEMICAL . WOOD WOOD FIBER PULPS
PULP
Alabama
Alaska
Arizona
Arkansas
California
Colorado
Connecticut
Delaware
District of Columbia
Florida
Georgia
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
New Hampshire
New Jersey
New York
North Carolina
Ohio
Oklahoma
Oregon
Pennsylvania
Puerto Rico
Rhode Island
South Carolina
Tennessee
Texas
Vermont
Virginia
Washington
West Virginia
Wisconsin
TOTALS
13,125
850
4,645
5,254
110
1,798
168
7,910
13,765
830
3,728
. 1,470
250
340
705
12,722
7,812
1,591
3,502
9,306
4,078
4,265
410
1,050
2,138
5,393
6,712
5,743
7,863
2,645
8,694
7,455
190
275
6,643
4,814
5,988
530
6,505
7,066
230
9,300
185,333
8,745
640
600
4,559
1,860
425 7,580
450 13,025
917
600
10,135 115
1,450 3,505
825
120 750
4,570
1,200
700
200 750 150
5,660
275- 740
1,300
805 5,431
900
4,454
28 1,275 459
4,540
4,550
3,880 5,411
1,478 ' 1,305
9,751 96,887 724
725
240
340
700
250
360
300
1,083
1,175
400
50
550'
220
520
800
350
250
240
125
1,271
755
1,175
460
920
13,259
1,440 50
180
400
65 55
120
100 30
635
2,820
45
225
778
435 3,380
44
365
650
350 100
1,490
50
•-
650
985
1,860
50
250
944
907 250
15,253 4,400
210
100
185
1,427
457
200
27
300
770
155
100
106
175
170
145
1,095
100
90
16
11
475
1,390
235
699
53
135
493
525.
375"
5
725
1,945
12,888
50
650
75
130
320
665
485
70
245
16
200
7
534
375
300
4,122
*includes dissolved pulp1
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Table 2. New Pulp and Paper Mills Under Construction and Projected
for the United States1
CRANE & CO., INC., DALTON, MASS.:
Under construction-new paper facility for the production of security
papers, to replace the Government mill at the same location.
Completion set for 1975.
FORT HOWARD PAPER CO., MISKOGEE, OKLA.:
Projected-tissue mill.
GREAT NORTHERN NEKOOSA, MAINE (No location specified):
Proposed-bleached hardwood kraft pulp mill, no date set.
HUDSON PULP & PAPER CO., PALATKA, FLORIDA:
Proposed-newsprint mill to produce 400 tpd from wastepaper, no date
set.
INLAND CONTAINER CORP., INDIANAPOLIS, IND.:
Under construction-350 tpd corrugated medium mill to use 100%
recycled fiber. Completion set for 1975.
MACMILLAN BLOEDEL, RICHMOND, CALIFORNIA:
Under construction-pulp mill to produce 100 tpd market pulp.
Completion set for Spring, 1976. Projected-recycled newsprint
mill at same location
OAK PULP & PAPER CO., POTEAU, OKLA.:
Proposed-300 tpd dissolving pulp mill, no date set.
ROBEL TISSUE MILLS, INC., PRYOR, OKLA.:
Under construction-tissue mill by Skybel Tissue Mills, Inc., of
Holyoke, Mass. Completion set for 1975.
SCOTT PAPER CO.,- HINCKLEY, MAINE:
Under construction-750 tpd bleached kraft mill and sawmill to replace
the 450 tpd sulfite mill at Winslow, Maine. Completion set for 1975.
VIRGINIA FIBRE CORP., RIVERVILLE, VA.:
Under construction-500 tpd corrugating medium mill. Completion set
for 1976.
WEYERHAUSER CO., NORTH CAROLINA (No location specified):
Froposed-fiberboard mill. Completion set for 1975-1976.
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2.0 PROCESS DESCRIPTION 2,3,4,5,6
The sulfite pulping industry is characterized by several different pro-
cesses, differing mainly in base chemical used and levels of chemical
and heat recovery practiced. Different schemes exist for each process
so that no one flow diagram can represent accurately the precise technique
employed at more than one plant.
In general, basic operations can be identified which are common at most
if not all plants. These are:
1. Digestion of chips;
2. Pulp washing; and
3. Chemical manufacture, recovery,and fortification.
Figure 1 illustrates the basic operations associated with magnesium-
base pulping and recovery. This is only one of many schemes currently
practiced. Pollution sources and their control from each process and
operation are discussed in Section 3.0.
2.1 DIGESTION
Delignification of wood chips is performed in large cylindrical vessels
o
of up to 6000 ft and capable pf handling 20 tons of wood chips. In a
batch-mode, the .digesters are charged with chips, the cooking liquor
containing essentially an acid bisulfite solution is added, and live
steam is turned on. The pressure is raised to about 110 psi. The
temperature increases until the desired value is reached; then the
steam is shut off and the reaction mixture is held for a period of time
sufficient to permit the principal chemical reactions to take place,
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Chips
Steam lor
Process and Power
•p
Figure 1. Simplified Process Flow Diagram of Magnesium-Base (Magnifite )
Process Employing Chemical and Heat Recovery
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these being the sulfonation and solubillzing of lignin with the bisulfite
and the hydrolytic splitting of the cellulose-lignin complex. During the
cooking cycle, constant pressure is maintained by drawing off amounts of
liquid and gas through a relief system and returning these to a liquor
storage tank or high pressure accumulator.
Toward the completion of the cooking cycle the pressure and temperature
are lowered by removal of further amounts of liquor and gas from the
digester to the high pressure accumulator by means of the relief system.
The final pressure in the digester will be about 30-40 psi and the
solution will contain primarily bisulfite with only a little sulfurous
acid. The exact combination of pressure, temperature and cooking time
will vary considerably from plant to plant.
The digester can be emptied by a variety of methods, the most common of
which is blowing. In this case, a large valve situated near the base of
the digester is opened and the material in the digester is blown under
the remaining pressure in the vessel into a pit. Large amounts of steam
containing significant amounts of sulfur dioxide are liberated. This
can be a significant source of pollution if the blowpits are vented to
the atmosphere. It is possible to recover the sulfur dioxide in
scrubbers designed for this purpose.
In order to minimize potential pollution due to blowing, some plants
employ a technique known as dumping. When this technique is utilized
a more elaborate pressure relief system is required. The aim is to
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relieve digester pressure to "near-atmospheric" by methods similar to
those employed in blowing.
Thus, the SC>2 evolution potential is greatly diminished when the contents
of the digester are removed. A common technique practiced with the dump
system involves the removal of the pulp and spent liquor by use of
recirculating liquor pumps. In this manner the emission of large quanti-
ties of sulfur dioxide-laden gas is abated. Water vapor and other gases
which may flash off in the dump tank can be treated by the acid absorp-
tion system without the penalties of lower absorption efficiencies.
A variation of the above technique sometimes is used wherein a portion of
the cooking liquor is withdrawn at the end of a cook and replaced with
wash water. This lowers the pulp and liquor temperature below the
boiling point and effectively keeps water and SC>2 from flashing off.
After the digestion operation and subsequent discharging, sulfite spent
liquor drains through the bottom of the blowpit and either is treated and
disposed, incinerated, or sent to a plant for recovery of heat and chemicals.
2.2 WASHING AND KNOTTING
The pulp, after separation from the spent liquor, is suspended in water and
processed through screens and centrifugal cleaners for removal of knots,
bundles of fibers, and other materials. Washing and knotting are considered
to be very minor sources of sulfur dioxide emissions. If however, other
sources are well controlled, washing and knotting can be a significant
portion of the total plant emissions.
7
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2.3 CHEMICAL MANUFACTURE, RECOVERY AND FORTIFICATION
The choice regarding whether chemical recovery is desirable is dictated
by the following:
1. Costs of chemicals and their recovery;
2. Base Chemical (Calcium, Ammonia, Sodium, or Magnesium) used in
conjunction with sulfurous acid; and
3. Regulations limiting plant effluents and emissions.
2.3.1 Calcium As Base
Calcium was the initial base-of-choice in the sulfiting industry while
there was a good availability of low resin spruce, fir, and hemlock.
It is gradually being replaced by ammonia, sodium, and magnesium bases.
When calcium is utilized, chemical and heat recovery usually are not
practiced due to formation of scale in the evaporation steps preliminary
to recovery, as well as formation of calcium sulfate ash in the furnace.
In lieu of the above, an acid plant of sufficient size to fulfill the
total sulfite requirement for pulping is required. It is obtained by
absorption of sulfur dioxide in water in a wide variety of packed
towers. The sulfur dioxide is manufactured as follows:
Sulfur is burned at over 2000°F under conditions designed economi-
cally to maximize yield in a rotary sulfur burner or a spray
sulfur burner. Gas thus formed is quickly cooled under conditions
of low oxygen by surface heat exchangers. It also may be cooled
directly by passage through a water spray.
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Cooled gas Is then absorbed in Jenssen towers which are acid
resistant tile-lined and packed with limestone in accordance
with the reaction H20 + S02 + CaC03 = Ca (HS03)2 + H20 + C02.
The resulting solution forms the bisulfite-sulfurous acid liquor
required for pulping.
Although most of the sulfur dioxide is absorbed in the Jenssen towers,
the acid plant can be a significant source of S02 emissions if secondary
emission controls are not used following the Jenssen towers.
2.3.2 Ammonia As-A Base
The use of ammonia as a sulfite pulping base has increased as calcium
pulping has diminished. Increased production rates, better yield,
applicability to a wider range of woods,and greater ease of processing
and process control are given as reasons for the switch.
Aside from the above, ammonia based spent pulping liquor is ideal fuel for
burning in recovery furnaces. It yields an ash-free combustion product.
Ammonia generated in firing decomposes to nitrogen and hydrogen (which goes
to water vapor). Heat is recovered by the burning of spent liquor in a
furnace for steam production. Sulfur dioxide is recovered from the flue
gas in an absorption system by use of anhydrous or aqueous ammonia to pro-
duce ammonium bisulfite used for pulping. It is necessary to burn some
sulfur as described above to provide make-up sulfur dioxide. This sulfur
dioxide is absorbed in the system serving the recovery furnace. Thus, acid
plant emissions are accounted for by the recovery plant,
9
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2.3.3 Magnesium As A Base
Along with ammonia, magnesium base pulping is one of the most commonly
used sulfite pulping processes today. Advantages cited are:
1. Higher production rates can be attained using high reaction
temperatures if proper pH control is maintained.
2. Wide variety of pulp can be made.
3. Pulping operations are simplified because the need for the
relief step is lessened and consideration may be given to use
of continuous digesters.
4. A simple system is available for recovery of heat and total
chemical (magnesium and sulfur dioxide). The system is that
shown in Figure 1.
t>
In the magnesium based system (Magnefite process in this case), weak
red liquor is concentrated in multiple-effect evaporators and a direct
contact evaporator from 9 percent to 55 - 60 percent solids. Strong li-
quor is sprayed into the furnace (of which Figure 2 is typical) and burned,
producing sufficient steam to run the evaporators as well as the cooking
cycle. Flue gases are laden with magnesium oxide which is in the form
of a fine white powder,: removable by means of multiclone units. It is
then steam slaked to produce magnesium hydroxide used in the sulfur di-
oxide absorption system.
After recovery of magnesium oxide, flue gas containing 1 percent sulfur
dioxide is routed through a system of four venturi scrubbers, the first
of which serves to cool the gas. The following three Venturis (illus-
trated in Figure 3) continue the scrubbing action and achieve a high
(98 percent) efficiency of sulfur dioxide removal. Slurry from the
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[f—:l_i -Lift Induced Draft
L fi PJl !| Fan il
1_
Figure 2. B&W Water-Cooled Furnace Magnesium
Base Recovery Unit.
Acid from
Cooling
Venturi
Slurry Recirculation
to Slaking Tank
rry from
Slaking Tank
I
Product Acid
Figure 3. Sulfur Dioxide Absorption System.
11
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slaking tank is the scrubbing medium. The pH of the scrubbing solution
in each venturi is monitored and controlled by manipulating recycle rates
and slurry flows. The resulting solution is passed through a fortification
tower which provides make-up S02 and which ultimately is vented through
the recovery system stack. A liquor of magnesium bisulfite resulting
from the above treatment is then used in the cooking cycle.
2.3.4 Sodium As A Base
Sodium pulping yields a pulp which is considered to be of fine quality.
It has the operating advantages mentioned for magnesium and ammonia and
furthermore can be accomplished at a wide range of acidity. Due to high
chemical cost, recovery is desirable.
Sodium based liquor may be concentrated and burned alone or in a recovery
furnace associated with a kraft mill. The products of sodium based
liquor burning are a smelt containing sodium sulfide with some sodium
carbonate and a flue gas containing sulfur dioxide. The smelt may be used
in a nearby kraft mill or it may be processed further to arrive at a
sodium carbonate solution which then is used to absorb sulfur dioxide from
flue gas. Make-up sulfur dioxide must also be added in order to arrive
at sodium bisulfite liquor which is used in the cooking cycle.
3.0 FACTORS AFFECTING EMISSIONS2'3'4'5
The acid sulfite pulping industry encompasses a broad spectrum of process,
specific practices, and control methods. Emission potentials are dependent
upon:
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1. Base chemical utilized;
2. Level of acidity, or pH at which digestion is carried out, affects
sulfur dioxide emissions from blow pits or dump tanks and any
other vents associated with cooking or washing;
3. Technique utilized in pressure relief system and in emptying
digester contents; and
4. Level of chemical and heat recovery practices.
Table 3 summarizes primary emissions sources and species.
3.1 BASE CHEMICAL UTILIZED
Base chemicals, namely sodium, ammonia, calcium and magnesium, affect
emissions insofar as they dictate the various process routes followed
which in turn do affect emissions. How the base chemicals are produced
and brought together with sulfur dioxide often necessitates specific
equipment such as absorbers designed for the special purpose of bringing
the constituents together and at the same time control gaseous and
particulate emissions. In the case of ammonium sulfiting, a potential for
ammonia emission exists.
3.2 LEVEL OF ACIj3ITY_Oj^ DIGESTION PROCESS
The pH as well as digestion temperature and pressure surely affect the
distribution of sulfur compounds in the gaseous, liquid,, and solid phase.
Acid sulfite pulping can take place at a wide range of pH levels. At
very low pH sulfur dioxide can exist as sulfurous acid in which form it
exerts considerable vapor pressure. At the intermediate pH ranges, sulfur
13
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Table 3. Sources and Emissions in Sulfite Mills
SOURCE
PRIMARY EMISSIONS
Blow pit or dump tank and
digester
Sulfur dioxide; water vapor; acid
mist
Knotters, washers
Sulfur dioxide
Recovery furnace
Sulfur dioxide; particulate matter
(depending on base); ammonia (if
ammonium base)
Acid plant
Sulfur dioxide
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dioxide exists as bisulfite ion which exerts a much lower vapor pressure
and presents less potential for sulfur dioxide emissions.
Table 4 indicates the predominant chemicals existing in various cooking
liquors and relates these to the pH of the solution. At a pH below 6, it
is proper to represent the sulfite in the cooking liquor as hydrosulfite
ion (HS03) while above this pH it is represented as sulfite ion (SO^). The
calcium and sulfite combination is insoluble in aqueous solution of pH above
2. Hence, calcium sulfite cooking liquors are limited to the acid sulfite
processes. Magnesium sulfite is soluble in solutions whose pH is below
7 (approximately), and it may be used in acid sulfite, bisulfite, and over
the lower end of the neutral sulfite range of pH. Ammonium sulfite is
soluble in solutions of a pH below 9 (approximately), while sodium sulfite
is soluble over the entire range of pH. The desired range of pH for the
cooking liquor will dictate the type of cooking chemicals which can be
used.
3.3 DIGESTER RELIEF AND DISCHARGE TECHNIQUES
These affect emissions at least as much as pH. During the cooking operation,
gas and liquid must be removed or recirculated in order to maintain proper
digester operating parameters. A pressure relief system of varying elaborate-
ness is employed which removes gas and liquid, returning these to accumulators
which also serve as holding tanks for pulping liquor. The final temperature
and pressure of the digested pulp are important keys in emission potential.
If these are high, large volumes of gas containing sulfur dioxide will be
released when the digester is discharged. From this point on, emissions
potential is based upon level of control practiced. Scrubbing is the method
15
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Table 4. Predominant Chemicals and pH of Sulfite Cooking Liquors
Process
Predominant Chemical
in Cooking Liquor
Approximate Initial
pH @ 25°C
Acid Sulfite
Bisulfite
Neutral Sulfite
Alkaline Sulfite
H2S03 + XHS03
XHS03
XS03 + XC03
XS03 + XOH
1-2
2-6
6-9H
16
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of choice, with any number of systems utilized for this purpose. They
include:
1. Jenssen scrubbing with lime rock;
2. Caustic scrubbers; and
3. Multi-staged packed scrubbers.
When digester contents are blown under high pressure, it usually is not
feasible to treat the vapors generated in the recovery plant or acid
plant, due to intermittent lowering of scrubbing efficiency caused by
the large volumes of gas.
Some plants have installed more elaborate pressure relief systems which
are capable of lowering digester pressure to "near atmospheric". The
digester contents then are pumped out into a tank with release of a volume
of vapor which is lower than that released when blowing is employed.
In conjunction with the above, it is possible to remove a portion of the
cooking liquor at the end of the digestion operation and replace it with
wash water, thus lowering the temperature below the mixture boiling
point. In this way, flashing of steam and sulfur dioxide is abated.
From this point on, emissions are dependent upon the control method
utilized. Vent gases can be treated by:
1. Horizontal - packed-bed scrubber;
2. Venting to the acid plant absorption system;
3. Venting to recovery cycle absorption system; and
4. Numerous other scrubbing methods.
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When blow pit or dump tank vapors are vented to the acid plant or recovery
system, emissions will be accounted for by these systems.
3.4 LEVEL OF CHEMICAL AND HEAT RECOVERY
If chemicals are not recovered, disposal of waste liquor (more than half of
the raw materials appears here as dissolved organic solids) presents
serious pollution problems. For this reason, as well as for economic
considerations, concerted attention has been focused upon the utilization
of the spent cooking liquor. If chemicals are not recovered, an acid
plant is necessary in order to produce the sulfurous acid required with
the base chemical. Sulfur dioxide emission potential is highest in this
operation since virtually all sulfur will exist in the form of S0£ which
must be absorbed. The sophistication of the absorption system will
affect sulfur dioxide emissions emanating at this step.
If chemical and heat recovery is practiced, sulfur dioxide from the flue
gas must be scrubbed out. Subsequent to this, a fortification step is
required to provide make-up S02 into the sulfurous acid-bisulfite solution.
Sulfur dioxide emission potential is similar to that of an acid plant
although the absorption system will be arranged in quite a different manner
as described in the process section.
If recovery of chemicals is practiced, particulate emissions occur but will
be minimal in the case of ammonia based pulping. Magnesium oxide fume is
the primary particulate matter from a magnesium based facility, although
most of it can certainly be recovered by multiclone units. When calcium
based liquor is burned, calcium is present as calcium oxide and sulfate
18
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entrained in the flue gas as finely divided fly ash. Chemical recovery
is infeasible when utilizing this process. Sodium based recovery presents
some opportunity for particulate emissions of sodium carbonate and sodium
sulfide. Usually, though, most of this material is recovered as a smelt
to be processed further for reuse or sold to kraft mills.
4.0 DEVELOPMENT OF ACID SULFITE PULPING EMISSION FACTORS
From the preceding sections, the difficulties in categorizing the sulfite
segment of the pulp industry readily can be appreciated. This is due to
the wide spectrum of combinations of bases, pH ranges and recovery schemes
in common practice. Thus typical emission factors applicable to all acid
sulfite pulping mills are impossible to specify.
4.1 COMPILATION OF DATA
Table 5 presents a summary of basic data collected during the course of
this study. The twelve plants from which data were collected comprise
55 percent of the nationwide capacity for sulfite pulp manufacturing.
Three major emission categories were determined. These are:
1. Digester relief and discharge system;
2. Recovery furnace; and
3. Acid plant.
The first category was broken down further according to type of control,
base, and digester discharge techniques. No correlation was made with
respect to pH since data were not available.
19
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Table 5. Summary of Emissions Data and Recovery/Control Methods from Acid Sulfite Pulping
Acid Plant Emissions
Company
Publishers Paper
Publishers Paper
Weyerhaueser
Weyerhaueser
Crown- Zellerbach
to
0 Great Northern
Scott Paper Co.
Scott Paper Co.
ITT Rayonier
Boise Cascade
Georgia Pacific
ITT Rayonier
American Can Co.
Location
Newberg, OR
Oregon City, OR
Cosmopolis, WA
Longview, WA
Camas, WA
Millinocket, ME
Everett , WA
Anacortes, WA
Port Angeles, WA
Salem, OR
Bellingham, WA
Hoquiem, WA
Greenbay, WI
Base Capacity ADUT/day* Ib S02/ADUT* Control Method
Mg
Mg
Mg
Mg
Mg
Mg
NH3
NH3
NH3
NH3
Ca
'Na
Ca
220
230
535
290
430
640
850
140
570
250
590
550
150
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
0.37
0.22
0.40
N.A.
0.60
0.168
7.7
N.A.
N.A.
N.A.
N.A.
N.A.
N.A.
Ammonia absorption followed by
water and caustic scrubbing.
Ammonia absorption, water scrub-
bing, control of process variables
Packed tower and Jenssen tower
with limerock.
N.A.
Hot described.
Not described.
Jenssen tower scrubber
a All data on emissions is from the period 6/75 through 7/76
* ABUT - Air Dried Unbleached Tons
N.A. - Not applicable because this system is not used.
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Table 5. Summary of Emissions Data and Recovery/Control Methods from Acid Sulfite Pulpinga (CONTINUED)
Blow Pit/Dump Tank Emissions
Company
lb S02/
ADUT '
lb S02/ „ 1 .. „. ,.
Amrr/M rt**^0 r Method
Comments
Publishers Paper Newberg, OR
Publishers Paper Oregon City, OR
Weyerhaueser Cosmopolis, WA
Weyerhaueser
Longview, WA
1.1
0.2
0.0
0.0
Crown-Zellerbach Camas, WA 2.08
Great Northern Millinocket, ME 6.4
Scott Paper Co. Everett, WA 0.499
Scott Paper Co. Anacortes, WA 25
ITT Rayonier Port Angeles, WA 0.367
Boise Cascade Salem, OR 0.0
Georgia Pacific Bellingham, WA 0.029
ITT Rayonier Hoquiem, WA 1.99b
American Can Co. Greenbay, WI
67
Unknown Multistaged-Packed Tower.
Unknown Horizontal Packed-Bed Scrubber
and digester pump-out system.
0-0 Pressure relief, dumping
and venting to recovery-
absorption system.
0.0 Pressure relief, dumping
and venting to recovery-
absorption system.
0.14 Unknown
Cool water added at end
of cycle.
0.08 Pressure Relief System vented
to Acid Plant. Condensation
system and scrubber.
33 None, other than pressure
relief system.
0.023 Packed Tower followed by
Jenssen lime rock scrubber.
0.0 Not described with regard
to blow, dump or pump. Vented
, to recovery-absorption system.
0.0006 Caustic scrubbing facility.
0.133b Chemical scrubber
0.464 Unknown
System installed in 9/73; S02
reduced by 98%.
System installed in 11/74; S02
reduced by 99%.
Dump tank emissions accounted for
as part of recovery furnace
emissions.
Dump tank emissions accounted for
as part of recovery furnace
emissions.
Magnefite process began in 1972.
Lower free S02 in cook liquor.
About 54% of plant serviced by
recovery system, 46% by acid
plant.
Qualifies ;for state small mill
requirement of 50% reduction.
Venting to recovery-absorption
reduced emissions from 401b/ADUT.
Scrubber is insufficient in its
capacity to handle volume of gas
evolved.
a All data on emissions is from the period 6/75 through 7/76.
b Unreliable data.
** lb S09/ADUT/min - Air Dried Unbleached Tons per each minute digester is blown. This unit is indicative
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Table 5. Summary of Emissions Data and Recovery/Control Methods from Acid Sulfite Pulping (CONTINUED)
Recovery System Emissions
Company
Location
Ib S02/ADUT Ib Part/ADUT Recovery Control
Publishers Paper
Publishers Paper
Weyerhaueser
Weyerhaueser
Crown-Zellerbach
Great Northern
Scott Paper Co.
Scott Paper Co.
ITT Rayonier
Boise Cascade
Georgia Pacific
ITT Rayonier
Newberg, OR
Oregon City, OR
Cosmopolis, WA
Longview, WA
Camas, WA
Millinocket, ME
Everett, WA
Anacortes , WA
Port Angeles, WA
Salem, OR
Bellingham, WA
Hoquiem, WA
12.7
10
9.8
8.18
5.85
9.2
4.54
N.A.
8.48
8.8
N.A.
0.193
1.8
2.1
3.04
4.85
2.76
2.7
0.765
N.A.
0.871
0.3
N.A.
3.77
Multiclones - MgO;
Multiclones - MgO;
Absorption System
Absorption System
Multiclones - MgO;
Multiclones - MgO;
Ammonia scrubbing
eliminator.
Ammonia scrubbing
eliminator.
S02 scrubber (95%)
Unknown
4 Venturi Scrubbers S02-
4 Venturi Scrubbers S02.
and Recovery not described .
and Recovery not described.
4 Venturi Scrubbers- SO 2.
4 Venturi Scrubbers-S02-
- SO followed by mist
- S02 followed by Brinks
followed by Brinks eliminator.
All data on emissions is from the period 6/75 through 7/76.
N.A. - Not applicable because this system is not used.
-------
Recovery furnace data are more generally applicable and classification of
emission levels is limited to process. Acid plant data, where applicable,
are also related only to process base.
While a sufficient amount of data were obtained from magnesium and ammonia-
based mills, data from sodium and calcium mills were sparse and of doubtful
value.
For each plant in Table 5, emissions data are presented for each of the
previously mentioned categories. The control systems are mentioned briefly
and commented upon. These are indicative of the diversity of practices
throughout the industry. Emissions are tied to the production rates of
unbleached pulp and presented as such.
4.2 TABULATION OF EMISSION FACTORS
Table 6 summarizes emission factors which are based upon Table 5. Values
presented are derived from the latest data (6/75 - 7/76) submitted by
plants in Oregon and Washington to their respective control agencies as
well as tests performed by EPA at Great Northern, Millinocket, Maine and
in house tests conducted by American Can Co., Greenbay, Wisconsin.
For the myriad of combinations of controls and recovery schemes, Table 6
should prove satisfactory if some specific plant data is available to
the person making estimates.
-23-
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Table 6. Emission Factors for Sulfite Pulping (Per Unit Weight of Air-Dried Unbleached Pulp)
EMISSION FACTOR RATING
PARTICULATE MATTER SULFUR DIOXIDE Measurec
Source
Digester
Relief
and b
Discharge
Recovery
System
a
b
Base Type Control
All -Untreated
MgO -Multistaged-
Packed Tower
-Horizontal-
Packed Bed
Scrubber &
Pump out
-Pressure
relief , dump-
ing, venting
to recovery
-Pressure re-
lief blowing
NHa -Pressure
relief &
scrubbing
-Pressure
relief only
Na -Pressure
relief &
scrubbing
Ca -Unknown
MgO -Multiclone
and venturi
scrubbers
NH3 -Ammonia ab-
sorption &
mist
eliminator
Ib/ADUT*
Neg
Neg
Neg
Neg
Neg
Neg
Neg
Neg
Neg
2.9
0.65
amis sj-ui
kg/ADUMT** Ib/ADUT kg/ADUMT Data
Neg 10-70 5-35 15
Neg 1-1 0.55 20
Neg 0.2 0.1 20
Neg 0.0 0.0
Neg 4.2 2.1 15
Neg 0.43 0.22 20
Neg 25,0 12.5 5
Neg
2.0 1.0 10
Neg 67.0 3.4 10
1.5 9.3 4.7 20
0.33 7.3 3.7 18
RANKING OF EMISSION FACTOR
1
i Process Engineering
Data Analysis TOTAL
5 5 25
5 5 30
5 5 30
5 5 25
5 5 30
5 5 15
5 5 20
5 5 20
8 8 36
5 7 30
Rank
C
B
B
C
.B
D
C
C
A
B
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Table 6. Emission Factors for Sulfite Pulping (Per Unit Weight of Air-Dried Unbleached Pulp)...CONTINUED
EMISSION FACTOR RATING
Source Base
Recovery Na
System
Acid NH3
Plant
Na
Ca
OtherC All
Sources
(Knotting,
Washing ,
Filtering,
etc.)
RANKING OF EMISSION FACTOR
PARTICULATE MATTER SULFUR DIOXIDE Measured
Type Control Ib/ADUT* kg/ADUMT** Ib/ADUT kg/ADUMT Data Data Analysis TOTAL
-Smelt 3.8 1.9 2.0 1.0 10 5 5 20
Recovery
Sodium
Carbonate
Scrubbing
-Ammonia Neg Neg 0.33 0.17 15 5 5 25
absorption,
water &/or
caustic
scrubbing,
Jenssen
scrubbing
-Unknownd Neg Neg 0.17 0.09 55 5 15
Jenssen Neg Neg 7.73.9 10 5 5 20
scrubbing
-Unknown Neg Neg 11.6 5.8 5 0 5 10
Rank
C
C
D
C
D
* ADUT - Air Dried Unbleached Ton
** ADUMT - Air Dried Unbleached Metric Ton
Emissions are long-term averages. Recovery systems are purged periodically resulting in higher instantaneous emissions.
Where blowing is practiced, emissions occur intermittently.
bDuring cooking cycle digester relief system transfers sulfur dioxide-laden gases to pressure accumulators where they
are reabsorbed for use in cooking liquor.
cThough these sources are considered minor, there is evidence which indicates that they are significant when major source
jare well controlled. Emission rates were derived from only one plant.
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4.3 METHOD OF ESTIMATION OF EMISSION FACTORS
In order to estimate the emission factors, the following method was used.
1. Data for the latest possible one-year period (usually 8/75 - 7/76)
was obtained from the responsible regulatory agency for each plant
within its jurisdiction.
2. Emissions from each source were averaged and tabulated by month.
3. A one-year mean for each plant source was calculated.
4. One-year means (Table 5) for similar operations and control
techniques between different plants were averaged to obtain the
values in Table 6.
5. For uncontrolled digesters, old data (1972-1974) were used from
several plants, and a range determined.
6_ For "other sources", the percent obtained from all sources other
than digesters and recovery operations during the 1975 EPA tests
at Great Northern, Millinocket, Maine, was used and applied- as a-
rough_estimate across the board.
4.4 RANKING OF EMISSION FACTORS
The reliability of the estimates in Table 6 is based upon criteria in which
each calculation is ranked according to the amount and type of information
utilized. Categories and numerical values are based upon:
Measured emission data: 20 points; maximum
Process data: 10 points; maximum
Engineering analysis: 10 points; maximum
-26-
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The contribution of each category to each factor was summed and ranking
was assigned as follows:
Numerical Rank Letter Rank
< 5 E (poor)
6-15 D (fair)
16-25 C (average)
26-35 B (good)
36-40 A (excellent)
For the purposes of this study, it is seen from Table 6, that most informa-
tion was present as emission data. This information which generally was
from the plants in question, was reconciled with the capabilities of the
control technology utilized at each specific plant and the process data
submitted. The qualitative engineering judgment of the contractor and
his knowledge of the current state-of-the-art was put to use in accomplishing
the above.
Since the information compiled was analyzed and related to three bases,
two emission contaminants, and thirteen control strategies, the reliability
is not as great as might have been expected if all sulfite plants used the
same process and technology.
-27-
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REFERENCES
1. Post's 1975 Pulp and Paper Directory. Miller-Freeman Publications,
1974.
2. Libby, C. Earle (Ed). Pulp and Paper Technology, Volume I.
McGraw-Hill, 1962.
3. Rydholm, Sven A. Pulping Processes. Interscience, 1965.
4. Babcock & Wilcox Company. Steam/Its Generation and Use. Babcock
& Wilcox, 1972.
5. Hendrickson, E.R., et al. Control of Atmospheric Emissions in Wood
Pulping Industry, Volume I. NAPCA, 1970.
6. Shreve, R. Norris (Ed). Chemical Process Industries. McGraw-Hill,
1967.
28
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APPENDIX
ADDRESS, PULP TYPES, AND
CAPACITIES OF ACID SULFITE MILLS
IN THE UNITED STATES
POST'S 1975 DIRECTORY
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ALASKA
Ketchikan.
Sitka.
FLORIDA
Fernandina.
MAINE
E. Mallinocket.
Winslow
NEW YORK
Glens Falls.
OREGON
Newberg.
Oregon City.
Salem.
WASHINGTON
Ketchikan Pulp Co., Box 1619 (99901)
Pulp Grades and Capacity: Dissolving magnesium
base sulfite 640 tpd, bleached pulp cap. 640 tpd.
Alaska Lumber & Pulp Co., Inc., Box 1050 (99835)
Pulp Grades and Capacity: Alpha pulp, magnesium
base dissolving sulfite.
ITT Rayonier, Inc., Zip (32034)
Pulp Grades and Capacity: Chemical cellulose 425 tpd,
(sulfite pulp) ammonia base.
Great Northern Paper Co., Zip (04430)
Pulp Grades and Capacity: Magnesium based sulfite,
groundwood 800 tpd (24 hr).
Scott Pap_er_ Co. , Zip (04901)
Pulp Grades and Capacity: Calcium based sulfite
pulp and sulfite screenings 490 tpd.
Finch, Pruyn & Co., Inc., 1 Glen St. (12801)
Pulp Grades and Capacity: Ammonium base bisulfite
200 tpd.
Publishers Paper Co., Box 70 (97132)
Pulp Grades and Capacity: Magnesium based unbleached
sulfite 220 tpd; groundwood 420 tpd.
Publishers Paper Co., 419 Main St. (97045)
Pulp Grades and Capacity: Groundwood 400 tpd,
magnesium based sulfite 320 tpd, bleached pulp 100
tpd.
Boise Cascade Corp., 315 Commercial St. S. (97301)
Pulp Grades and Capacity: Ammonia base sulfite 250
tpd.
Anacortes.
Scott Paper Co., 1709 R. Ave. (98221)
Pulp Grades and Capacity: Bleached, ammonia based
sulfite 140 tpd.
29
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Longview.
WASHINGTON (continued)
Bellingham. . Georgia-PacificCorp., Army & Chestnut Sts., Box 1236
(98225)
Pulp Grades and Capacity: Bleached, calcium based
sulfite 500 tpd.
Camas. Clrown^ Zellerbach. Zip (98607)
Pulp Grades and Capacity: Kraft 730 tpd, magnesium
based sulfite 430 tpd, bleached pulp 980 tpd.
Cosmopolis. Weyerhaeuser Co., Zip (98537)
Pulp Grades and Capacity: Bleached sulfite 400 tpd.
Everett. Scott Paper Co., Zip (98201)
Pulp Grades and Capacity: Groundwood 30 tpd; ammonia
based sulfite 850 tpd.
Hoquiara. ITT Rayonier, Inc., Box 299 (98550)
Pulp Grades and Capacity: Chemical cellulose and
bleached sodium based sulfite paper-making pulps
475 tpd.
Weyerhaeuser Co., Zip (98632)
Pulp Grades and Capacity: Kraft 306 tpd; magnesium
based sulfite 280 tpd; corrugating medium 240 tpd;
bleached pulp 350 tpd.
ITT Rayonier, Inc., Zip (98362)
Pulp Grades and Capacity: Chemical cellulose and
bleached ammonia based sulfite paper-making pulps
475 tpd.
WISCONSIN
Appleton. Consolidated Papers, Inc., 1130 E. John (54911)
Pulp Grades and Capacity: Bleached calcium based
sulfite 140 tpd.
Brokaw. Wausau_Paper Mills Co., Zip (54417)
Pulp Grades and Capacity: Magnesium based sulfite
170 tpd.
Green Bay. American Can Co., Day St. (54305)
Pulp Grades and Capacity: Calcium based sulfite
150 tpd; groundwood 70 tpd.
Niagara. Niagara of Wisconsin_PaperCorp., Zip (54151)
Pulp Grades and Capacity: Groundwood 150 tpd;
bleached sulfite pulp 120 tpd.
Port Angeles.
30
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WISCONSIN (continued)
Oconto Falls.
Park Falls.
Peshtigo.
Port Edwards,
Rothschild.
Scott Paper Co., Central Ave. (54154)
Pulp Grades and Capacity: Ammonia based sulfite
123 tpd; bleached pulp 123 tpd.
Flambeau Paper Co., 200 N. 1st Avenue (54552)
Pulp Grades and Capacity: Calcium based sulfite
120 tpd; bleached pulp 110 tpd.
Badger Paper Mills, Inc., W. Front St., Box 149
(54157)
Pulp Grades and Capacity: Bleached, calcium based
sulfite 120 tpd.
Nekoosa Edwards Paper Co., Inc., 100 Wisconsin River
Dr. (54469)
Pulp Grades and Capacity: Magnesium based sulfite
235 tpd.
Weyerhaeuser Co., Box 200 (54474)
Pulp Grades and Capacity: Bleached, calcium based
sulfite 200 tpd.
31
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
, REPORT NO.
EPA-450/3-77-005
2.
3. RECIPIENT'S \CCESSION-NO.
4. TITLE AND SUBTITLE
5. REPORT DATE
January 1977
Background Document: Acid Sulfite Pulpina
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
Al Linero
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
Environmental Science and Engineering, Inc.
University Station
Gainesville, Florida 32604
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-02-1402
Task Order 14
12. SPONSORING AGENCY NAME AND ADDRESS
U.S. Environmental Protection Agency
Office of Air and Waste Management
Office of Air Quality Planning and Standards
Research Triangle Park, North Carolina 27711
13. TYPE OF REPORT AND PERIOD COVERED
Final
14. SPONSORING AGENCY CODE
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The sulfite pulping industry primarily is characterized by the type of base
chemical used in conjunction with sulfurous acid to effect delignification of
gymnosperm woods. It further is characterized by the level of acidity during the
digestion operation and by the extent of recovery of chemicals and waste heat.
This renort describes the methodology used in obtaining emission factors for
AP-42, Compilation of Air Pollutant Emission Factors on acid sulfite pulpina.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/QPEN ENDED TERMS
c. cos AT I Field/Group
Emissions
Acid Sulfite Pulnina
Diaestion Process
18. DISTRIBUTION STATEMENT
Release Unlimited
19. SECURITY CLASS (This Report)
Unclassified
21. NO. OF PAGES
28
20. SECURITY CLASS (This page)
Unclassified
22. PRICE
EPA Form 2220-1 (9-73)
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ENVIRONMENTAL PROJECTION AGENCY
Technical Publications Branch
Office of Administration
Research Triangle Park, North Carolina 27711
POSTAGE AND FEES PAID
ENVIRONMENTAL PROTECTION AGENCY
EPA -335
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AN EQUAL OPPORTUNITY EMPLOYER
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