EPA910/9-92-«3i=
&EFA
UnitedStates
Environmental Protection
Agency
Region 10
1200 Sixth Avenue
Seattle WA 98101
Alaska
Idaho
Oregon
Washington
Management Division
Program Planning & Evaluation
September 1992
Pollution Prevention for the Kraft Pulp and
Paper Industry
Bibliography
-------
910992031
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
BIBLIOGRAPHY
Prepared for
U.S. EPA Region 10
1200 Sixth Avenue
Seattle, Washington 98101
EPA Contract No. 68-C8-0062, WA 3-63
SAIC Project No. 01-0832-03-1013
Prepared by
Science Applications International Corporation
626 Columbia Street NW
Olympia, Washington 98501
SEPTEMBER 1992
-------
TABLE OF CONTENTS
1.0 CHIP PREPARATION 1
2.0 CHEMICAL PULPING 2
3.0 PULP WASHING 8
4.0 BLEACHING 12
5.0 CHEMICAL RECOVERY 27
6.0 RECAUSTICIZING 32
7.0 POWER GENERATION 34
8.0 WASTEWATER TREATMENT 36
9.0 PAPERMAKING 44
10.0 GENERAL PLANT 45
-------
CHIP PREPARATION
NUMBER
T1UE
AUTHOR
REFERENCE
SYNOPSIS
1.0 CHIP PREPARATION
1.1 Removal of chips
thins as fines -
effect on pulping
variables
1.2 An automated chip
quality analysis
system - a tool for
improving chip
quality
1.3 Refining intensity,
energy consumption
and pulp quality in
two-stage chip
refining
Pemble, G. G.
Mclnnis, Dukes,
Lawrence and
Andrews
Miles, May and
Kami s
TAPPI Proceedings,
Pulping Conference
Book 1, 1990, pp.
61-63
TAPPI Proceedings,
Pulping Conference
Book 1, 1990, pp.
65-76
TAPPI Proceedings,
Pulping Conference
Book 2, 1990, pp.
681-690
In an attempt to remove as high a percentage of <4.8 mm round hole
fines as possible, a 2.9 nm slotted opening Mas tested and later
installed in our gyratory fine screens. Not only was the <4.8 mm
round holes fines removal increased, but the removal of 2.9 mm "thins"
brought a number of process improvements. This paper is a chronicle
of mill's experience with these improvements in key pulping variables.
A Gradex Particle Size Analyzer has been coupled to a PC based data
information system. The PC system, utilizing standard database and
graphical packages, allows easy and rapid analysis of chip quality
data. This data has been organized in various forms: chip ranking,
vendor update letters, trend and SPC graphical presentations to
improve in-mill and purchased chip quality and to understand the
impact of chip quality on mill operations.
Thermomechanical pulps were produced in two pilot installations. Both
were conventional two-stage systems in which the first stage was
pressurized and the second atmospheric. Analysis of the experimental
results showed that at a given specific energy pulp quality was
improved, or for a given pulp quality the energy consumption was
reduced when the first stage refining was carried out at a high
rotational speed or low consistency. There were indications that
these benefits could be enhanced if the second stage were operated at
a low refining intensity.
POLLUTION PREVEMTIOM FOR THE KRAFT PULP AMD PAPER INDUSTRY
-------
CHEMICAL PULPING
MUHBER
TITLE
AUTHOR
REFERENCE
2.0 CHEMICAL PULPING
2.1 Soda ash - the
papermaker's
alternative to
caustic soda
2.2 The recovery of by-
products and pulping
chemicals from
industrial soda
bagasse spent
liquors
2.3 The basics of foul
condensate stripping
2.4 Studies on alkali -
oxygen-anthraqui none
dellgnificat Ion of
bagasse
2.5 Kraft pulping for
the environment of
the 90's
2.6 RDH kreft pulping to
extend
delignif(cation,
decrease effluent,
and improve
productivity and
pulp properties
2.7 Design
considerations for
condensate
segregation and
methenol/TRS
stripping
Wort ley, Barbara
Venter, J.S.N.,
and Vender
Klashorst, G.H.
Burgess, T.
Upedhyaya,
Chinnapadasan,
Rajan, Singh and
Dutt
Barrett, K.
Andrews, E.K.
Beckstrom, B.
PINA Magazine, March
1988
TAPPI Proceedings,
April 1987
Environmental
Conference, pp. 79-
86
TAPPI Press,
Environmental
Issues: An
Anthology of 1989,
pp. 241-246
TAPPI Proceedings,
Pulping Conference
Book 1, 1990, pp.
337-343
TAPPI Press,
Environmental
Issues: Anthology
of Published Papers,
1990, pp. 44-51
TAPPI Journal,
November 1989, pp.
55-61
TAPPI Press,
Environmental
Issues: Anthology
of Published Papers,
1990. pp.335-345
Large amounts of lignin end hemicellulose are dissolved during soda
pulping of bagasse and other agricultural plants. The spent liquor is
usually concentrated and burnt to prevent pollution. The energy
balance is usually negative and soda cannot be recycled unless silica
is removed.
Foul condensates from the digesters and evaporators contain reduced
sulfur gases and organic compounds which contribute to pulp mill water
pollution in the form of BOD toxicity. They can also create odor
problems in the mill and at the secondary treatment system.
The proposed study was undertaken to assess the suitability of bagasse
by alkali-oxygen delignification process and to know the effect of
anthraquinone (AQ) on pulp and paper characteristics.
This paper summarizes the latest information on the Beloit RON system
of Batch digester heat recovery.
Status of the RDH pulping process and how it compares with oxygen
delignification in terms of pulp strength, pulp yield, and effluent
loading.
A discussion is presented on the importance of considering a
condensate stripping system as an entity of its own and not just an
appendage to other equipment. The importance of condensate
segregation is presented along with design principles used to optimize
stripping system importance.
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
CHEMICAL PULPING
MWBER
TITLE
AUTHOR
REFERENCE
2.8 Effect of entrained
black liquor carry-
over on medium-
consistency oxygen
delignification
Miller, U.J.,
Lhackford, H.
Jiang, and
Genco, J.
TAPPI Journal,
February 1991, pp.
117-122
Solids carry-over causes inefficiency in oxygen delignification, but
increasing the amount of sodium hydroxide can correct the problem.
The use of three stages of pre-oxygen washing and two stages of post-
oxygen washing is recommended.
2.9 On-line oxygen
delignification
control
2.10 Extended
delignification, an
alternative to
conventional kraft
pulping
2.11 PRENOX process-
experiences from a
pilot plan
installation
2.12 North America's
first fully
Integrated, medium
consistency oxygen
delignificetion
stage
2.13 Ozone
delignification of
black spruce and
hardwood kraft,
kraft-anthraquinone,
and soda-
anthraquinone pulps
Anon.
Nera, F.E, and
Chamberlin, J.L.
Simonson, 0.,
Lindstrom, L.A.,
and Marklund, A.
Enz, S.N., and
Emmerling, F.A.
Liebergott, N.,
and van Licrop,
B.
TAPPI/CPPA
Proceedings, 1988
International Pulp
Bleaching
Conference, Orlando,
Florida, June 1988
TAPPI Journal,
January 1987, pp.
132-136
TAPPI Journal,
August 1987, pp.
73-76
TAPPI Journal, June
1987, pp. 105-112
TAPPI Journal, June
1981, pp. 95-99
Discussion of control system for oxygen delignification based on on-
line Kappa number measurement. System reduced average Kappa number
and production costs.
Mill and pilot plant data for market grade bleached pulp were
evaluated. The pulp quality was equivalent to or better than that of
bleached pulps obtained by conventional kraft pulping and bleaching
techniques. However, operating parameters favored extended cooking in
the rapid displacement heating process. These parameters were lower
active alkali consumption, lower bleaching chemical demand, and lower
bleach plant effluent liability.
Study showing that high-consistency treatment of pulp with N02 and 02
before the oxygen delignification stage can produce pulp with a Kappa
number of 7 and significantly reduce bleach-plant pollutants.
Consolidated Paper, Inc. has installed a medium-consistency oxygen
delignification reactor in the hardwood pulp line at its kraft mill in
Wisconsin Rapids, Wisconsin. System has resulted in a decrease in
Kappa nunfcer, increased production and brightness and a decrease in
chemical consumption.
After ozone delignification followed by DED treatment, black spruce,
and mixed hardwood kraft, kraft-AQ and soda-AQ pulps attained 89-92X
brightness (ISO) and compared to conventionally bleached CEDED pulps,
required less Clo2 in the third and fifth stages, had somewhat lower
strength properties for black spruce but similar strength for hardwood
pulps, and gave effluents and color loadings that were 60-75X lower.
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
CHEMICAL PULPING
NUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
2.U Oxidation of pulp
with N02/02 prior to
oxygen
delignification - a
novel process with
potentially less
pollution
2.15 Delignifying high-
yield pulps with
oxygen and alkali
2.16 Oxygen
delignification
systems: optimum
design syntheses
2.17 Oxygen
delignification
technology: state-
of-the-art report on
advances
2.18 System using medium-
consistency oxygen
bleaching works in
Sweden
2.19 Oxygen
delignification at
medium consistency
can raise yield, cut
BOD
2.20 Oxygen/alkali
delignification at
medium consistency
Brannland, R.,
Lindstrom, L.A.,
Norden, S., and
Simonson, 0.
TAPPI Proceedings,
1985 International
Bleaching Conference
Kleppe, P.J.,
and Storebraten,
S.
Edwards, L.,
Myer, H., and
Haynes, J.
White, F.
Nasman, I.E.
Markhem, L.D.,
and Magnotta,
V.L.
Kleppe, P.J.,
Knutsen, P.C.,
and Jacobsen, F.
TAPPI Journal, July
1985, pp. 68-73
TAPPI Seminar
Proceedings,
Bleaching and the
Environment,
Seattle, Washington,
September 1988, pp.
333-356
Paper Trade Journal,
February 28, 1982,
pp. 27-30
Pulp & Paper,
October 1981, pp.
137-138
Pulp & Paper,
October 1981, pp.
139-142
TAPPI Journal, June
1981, pp. 87-90
Four companies AGA, KemaNord, MoOo and Sunds Defibrator are jointly
exploring a new delignification process. With this process,
characterized by a pretreatment of pulp prior to oxygen
delignification with a combination of N02 and 02 it is possible to
delignify softwood kraft pulp to Kappa numbers below 10. In this
paper we will discuss what impact this process will have on chemical
composition and environmental effects of spent liquors produced in a
subsequent bleaching process. Results will be compared with those from
bleaching of oxygen delignified pulp. Also matters related to working
environment and emission to air will be covered.
Discussion of delignifying high-yield pulps with oxygen and alkali by
using a two stage pulping process. Pulp properties, sack paper
production and linerboard production are discussed.
Simulation and optimization techniques are used to determine the best
combination of equipment and operating conditions from an oxygen
delignification system including washing. Both capital costs and
operating costs are considered. For example, "What is the optimum
dilution factor and amount of washing equipment and how should the
equipment be divided between pre and post oxygen stage washing?"
Evaporator and environmental constraints are also taken into account.
Oxygen and ozone delignification in the bleaching of kraft pulps are
compared. Medium consistency oxygen delignification of kraft pulp is
described. Aspects of low cost peroxide bleaching to high brightness
are covered, and hydrogen peroxide in chemical pulp bleaching is
discussed.
SCA mill at Ostrand has successfully run a full-scale oxygen-caustic
extraction stage. The advantages of oxygen plus oxygen-extraction
stage are described.
General discussion of oxygen delignification including advantages and
disadvantages, process, pulp yield, and effluent reduction.
The sequence of events leading to the development of a mi 11-scale
oxygen/alkali delignification process at medium consistency is
described. The process, which takes pulp directly from the blow line
of a continuous digester, is also presented.
POLLUTIOM PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
CHEMICAL PULPING
MUHBEK
TITLE
AUTHOR
REFERENCE
SYNOPSIS
2.21
2.22
2.23
2.24
2.25
2.26
Experience with
extended
delignification of
hardwood end
softwood kraft pulp
in a continuous
digester
Nitrogen dioxide
preoxidation oxygen
delignification - a
process for the
future?
Oxygen
delignification
systems:
synthesizing the
optimum design
Modified kraft
cooking - ways of
application
Kortlainen,
V.A., and
Backlund, E.A.
TAPPI Journal,
November 1985, pp.
70-74
Two case studies on
the cold blow
technique for batch
kraft pulping
Rapid Displacement
Heating in Batch
Digesters
Lindqvist, B.,
Harklund, A.,
Lindstrom, L.A.,
and Norden, S.
Meyers, M.,
Edwards, L., and
Haynes, J.
Sandstrom, P.E.,
Farming, A.M.,
Soderqvist,
Lindblad, H.,
and Teder, A.
Sjodin, L., and
Pettersson, B.
Swift, L.K., and
Dayton, J.S.
TAPPI Proceedings,
1985 International
Pulp Bleaching
Conference,
pp. 221-225
TAPPI Journal, April
1989, pp. 131-135
TAPPI Seminar
Proceedings,
Bleaching and the
Environment,
Seattle, Washington,
September 1988, pp.
279-286
TAPPI Journal.
February 1987, pp.
72-76
Pulp & Paper Canada,
89:8, pp. T264-T270
A multistage continuous kraft pulping process that provides a more
selective delignification than conventional kraft cooking is in
commercial operation at a mill in Finland. This improved selectivity
is used to lower the pulp's Kappa number, which has contributed to
reductions in the consumption of bleaching chemicals, to reductions in
the effluent load of the bleach plant, and to an increase in the
bleach plant's production capacity. When compared at the same Kappa
number, the modified pulp has a higher viscosity, better strength and
consumes less bleaching chemicals then a conventional kraft pulp.
Operating experiences, consumption data and pulp-quality data for
hardwood and softwood kraft pulps are reported.
In order to produce a low Kappa number pulp after an oxygen stage,
nitrogen dioxide preoxidation was superior to modification of the
kraft cook. Kappa number 9-10 should be compared to 13-14 in the
latter case. A number of these methods made it possible to further
reduce the Kappa nurrfoer to about 8 after the oxygen stage. Kappa
number reduction from 17-9, the first figure representing a
conventionally cooked and oxygen bleached kraft pulp, decreased the
consumption of active chlorine up to 55X. COD, B006 and total organic
chlorine were reduced with 55%, while color was reduced with 7SX.
The authors used computer simulation to synthesize the best
configuration of washing equipment and determine the optimum dilution
factor for a typical oxygen delignification system.
Modified kraft cooking is based on principles that originate from the
kinetics of delignification and carbohydrate degradation. Some of the
principles contradict others, so it is therefore necessary to optimize
process conditions to gain a net improvement in pulping selectivity.
This paper presents how different ways of applying the principles can
be evaluated using a mathematical model of continuous kraft pulping.
Mill trials and laboratory investigations show that correctly applied,
the principles result in a process that both reduces bleach plant
effluent and operating costs while maintaining the pulp quality. The
modified kraft cooking process can probably be even further improved
based on advancing knowledge in the field of pulping chemistry.
The ASSI Karlsborg mill is the first to practice extended
delignificatlon and cold blow process techniques in its batch digester
plant, and the NCB Dynes mill started up a completely new batch cold
blow digester plant recently.
Rapid Displacement Heating (RDH) has now reached full commercial
operation in two mills. In addition to dramatic digester area steam
savings these mills have experienced reduced soda loss off brown stock
washers; reduced evaporator load lower strong black liquor
viscosities; increased digester production and improved pulp quality.
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
CHEMICAL PULPING
NUMBER
. TITLE
AUTHOR
REFERENCE
SYNOPSIS
2.27 Dioxin/furan in-mill
source studies at
Consolidated Papers,
Inc.'s kraft
division
2.28 Modified continuous
cooking
2.29 Oxygen
delignification
2.30 RDH pulping - better
pulp properties
through improved
selectivity
2.31 Peroxide
delignification of
unbleached chemical
pulp by minox
process
2.32 New catalyst
improves polysulfide
liquor makeup, 02
delignification
2.33 PRENOX - oxidation
of pulp with
nitrogen dioxide and
oxygen prior to
oxygen
delignification
could reduce
pollution
2.34 Reduce TOCl with 0x0
process
Weinbauer, J.,
and Gilbert,
F.A.
Dillner, B.
Backlund, A.
Swift, L.K.
Carles, J.E.,
Lemoyne, H., and
Logan, U.R.
Lightfoot, U.E.
Brannland, R.,
and Simonson, 0.
TAPPI Proceedings,
1989 Environmental
Conference, April
1989. pp. 359-372
Paper presented at
Kamyr, Inc. Low
Chlorine Bleaching
Seminar, Atlanta,
1987-12-08
Paper presented at
Kemyr, Inc. Lou
Chlorine Bleaching
Seminar, Atlanta,
1987-12-08.
Unpublished,
available from
author of Beloit
Corporation
TAPPI Proceedings,
1980 Pulping
Conference, Atlanta,
GA, pp. 325-332
Pulp & Paper,
January 1990, pp.
88-93
Swedish Pulp & Paper
Journal No.2, 1966,
pp. 48-50, 53-54
Lachenal, D.,
and Huquet, H.
CPPA Annual Meeting
Preprints, 75B,
Montreal, Que.,
February 2-3, 1989,
pp. 187-192
Impact of oxygen delignification on hardwood bleach line reviewed.
Modified continuous cooking implies a con/counter-current process
where the alkali concentration is lower than normal viscosity, lower
Kappa number, equal or better strength and results in a reduction of
the effluent load by 25 to 30%.
Paper presents information relative to oxygen delignification.
Installations, costs, environmental effects and discussion of high and
medium consistency systems are presented.
The steam savings capability of the new ROM cooking technology has
been well documented. New studies are surfacing which are beginning
to explain why RDH cooking produces pulp of significantly higher
strength characteristics than other processes and further more, why
RDH cooking can be extended to extraordinarily low Kappa levels.
Unbleached chemical pulp can be delignified by hydrogen peroxide in an
alkaline medium. Laboratory results obtained on bisulfite end kraft
pulps are described. Using this process on kraft pulp a reduction by
45X of the bleach plant effluent color has been achieved, together
with savings in overall bleaching operation costs.
Paper deals with polysulfide cooking and its impact on the recovery
boiler. Use of polysulfide liquor makeup enables mills with limited
recovery boiler capacity to employ oxygen delignification. Costs are
provided which show that the ROI for the process is on the order of 6-
7 months.
Findings of pilot plant investigations in a mill in Sweden using
PRENOX process is discussed. PRENOX process reduced Kappa no. in pulp.
BOD,COO and TOCl are reduced with decreased Kappa no. Increased
washing and chlorine dioxide substitution further reduced TOCl.
Findings of 0x0 process investigations presented. 0x0 process
consists of oxygen delignification followed by low charge of chlorine
followed by oxygen extraction stage. 0x0 process can be optimized to
reduce chlorine requirement. Comparison with chlorine dioxide
bleaching processes reported.
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
CHEMICAL PULPING
NUMBER TITLE
2.35 Hill experience of
oxygen
delignification
2.36 Pretreatment of
pulps with chlorine
before oxygen
delignification
2.37 What's hot in
pulping? extended
delignification
2.38 Extended
delignification and
its potential for
environmental
improvements
2.39 In-PIant process
alternatives for
minimizing
discharges of AOX
AUTHOR
Kiumra. H.
Soteland, N.
Renard, J.J.
Blomberg, B.,
and Hartler, M.
Earl, P.P., and
Reeve, D.U.
REFERENCE
Japan TAPPI Journal,
42:1, January 1988,
pp. 52-55
Nordic Pulp & Paper
Research Journal,
October 1988, pp.
124-127
American Papermaker,
51:3, March 1988,
pp. 50-52
Nordic Pulp & Paper
Research Journal No.
4, December 1986,
pp. 25-29
Third Colloquium on
Pulp and Paper Mill
Effluents, Toronto,
Ontario, February
14-15, 1989
SYNOPSIS
Oxygen delignification in a mill in Japan reduced Kappa No. by 49X.
Chlorine consumption and COO in bleaching process reduced by 30X and
50% respectively.
Slight chlorination of pulp oxygen delignification reduces Kappa
number significantly at mill in Oslo, Norway. Results in low effluent
COO, TOCl and reduced mutagenicity.
Modifications implemented at a mill in the digester operations to
install extended delignification process is described. Developments
in chemical pulping alternatives to the kraft process are briefly
di scussed.
Improved selectivity in kraft pulping process is discussed. Host
important parameter for controlling selectivity is the lignin
concentration in the cooking liquor during final phase of cook.
Swedish process discussed, which results in a low concentration of
lignfn in the liquor, therefore a smaller bleaching chemical
requirement.
process alternatives for lowering the lignin content in pulp, better
Mashing techniques and chlorine dioxide substitution during bleaching
are discussed.
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
PULP WASHING
NUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
3.0 PULP WISHING
3.1
3.2
3.3
3.4
3.5
3.6
3.7
How to select the
optimum pulp washing
system
Cleveland, F.C.
and Johnston,
D.6.
TAPPI Journal.
February 1985, pp.
70-73
Channeling and
displacement washing
of wood pulp fiber
pads
Lee, R.F.
TAPPI Journal,
November 1984, pp.
100-103
Improving brownstock
washing through pulp
mat modeling
Pulp washing with
screw presses
Washing for Low
Bleach Chemical
Consumption
Rapid caustic
extraction before an
oxidative extraction
stage
The principles of
pulp washing
Kouris, Michael
Egenes and Barbe
Stromberg, C.
Misted, J.S. and
Canovas, R. Vega
Crotogino, R.H.,
Poirier, N.A.,
and Trinh, D.T.
TAPPI Journal, Vol.
67, No. 2, pp. 119-
121
TAPPI Proceedings,
Pulping Conference
Book 2, 1990, pp.
551-575
TAPPI Press,
Environmental
Issues: Anthology
of Published Papers,
1990, pp. 230-238
TAPPI Journal, July
1989, pp. 165-170
TAPPI Journal, June
1987, pp. 95-103
Selecting a pulp washing system for a particular kraft process,
whether greenfield or a renovation project, is a challenge facing
consultants and mill personnel alike. The problem is magnified
because of the variety of washing systems and their numerous
applications in today's market. This paper attempts to reduce a
potentially complex decision-making process to a series of logical,
common sense steps for choosing the optimum washing system for a
particular mill process.
Microscopic channeling is the primary mechanism controlling
longitudinal mixing during displacement washing. Trace quantities of
high-molecular-weight polymer in the wash liquor can improve
displacement efficiency by reducing channeling. The popular,
diffusion-like models for describing longitudinal mixing in a fibrous
pad are inadequate to account for many of the phenomena of channeling.
More rigorous models based upon the mechanism of channeling are
required to adequately interpret laboratory data and scale up these
data for design purposes.
A model derived to predict the washing efficiency of a displacement
washing screw press is presented. We assess the relative importance
of the operating variables on the washing efficiency of the press.
Results obtained from the mill trials with hardwood and softwood BCTHP
pulps are subsequently correlated with the theoretical predictions.
Laboratory results are used to explain the different organic solids
washing results displayed by different types of washers.
Rapid caustic extraction, using residual chemicals from an (E+0)
stage, can be achieved in seconds by displacement on a multistage
washer. This process decreases caustic consumption, and low AOX
(absorbable organic halogens) in the effluents.
A review of pulp-washing operations, dilution/extraction, displacement
washing, and parameters governing washer performance.
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
PULP WASHING
TITLE
AUTHOR
REFERENCE
SYNOPSIS
3.8
3.9
3.10
3.11
3.12
3.13
3.14
Optimizing the wash
water rate of
counter-current
washing systems
A unified treatment
of brounstock
washing on rotary
filters
Nierman, Herbert
H.
TAPPI Journal, March
1986, pp. 122-124
A method for
quantifying pulp
washer performance
that does not use
flow rate
measurements
A new type of hood
for bleach-plant
washers
Medium-consistency
pulp washer
generates superior
washing efficiency
The drum displacer
a new approach to
brownstock washing
Online entrained-air
measurement for
brownstock-washer
defoamer control
Cut Ifnan. Harry
T. Jr.
TAPPI Journal,
August 1986, pp. 88-
94
Oxby, Paul W.,
Sandry, Thomas
D., and
Kirkcaldy, David
M.
Bowen, G.L. and
Dix, K.A.
Pikka, Olavi E.,
Himanen, Juuso,
Ala-Kaila, Kari,
and Coffey,
Kenneth
Perkola, Markku,
Sundqvist,
Harry, Pikka,
Olavi, Qvintus,
Harri, and
Sainiemi, Jukka
Dougherty, Steve
J.
TAPPI Journal,
August 1986, pp.
118-119
TAPPI Journal, May
1990, pp. 239-242
TAPPI Journal, March
1990, pp. 121-126
TAPPI Journal,
February 1989, pp.
91-95
TAPPI Journal,
January 1989, pp.
50-54
The Norden efficiency can be used to predict the performance of
counter-current pulp washers, but reliable values are required. When
Norden efficiency values are calculated from test data on operating
systems, the results are too frequently unbelievable. The reliability
of these same test results can be significantly improved by using a
data adjustment technique which takes into account all of the
available information.
Countercurrent washing of pulp on rotary filters is a mass transfer
process amenable to analysis by the classical techniques of
nonequilibrium staged operations. Such analysis establishes the
connections among the overall, stage, and local efficiencies and the
underlying mass transfer rate in the wash zone. Performance and
design equations result that they are simple and straightforward.
Associated graphical depictions of the calculation scheme aid in
visualizing the concepts. Methods that are currently accepted fit
into this analysis in different ways. The result make clear where
fundamental research ought to be focused.
The MCDD washer has successfully been introduced in the oxidative
extraction stage of hardwood pulp bleaching, and its efficiency has
exceeded the performance values of a vacuum drum filter.
A drum displacer is a multi-stage pulp washer that enables the washing
stages to be carried out in a single drum.
A control system that meters defoamer based on measurement of
entrained air can reduce defoamer consumption by 40X.
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
PULP WASHING
NUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
3.15
3.16
3.17
3.18
3.19
3.20
3.21
3.22
Optimization of
filter washer
operation and
control
Advanced control for
brown-stock washers
Filtration theory as
applied to the
dimensioning of flat
band washers
Rapid caustic
extraction of
chlorinated pulp
Automated control of
washer shower water
at ITT Rayonier
Horizontal washing
at Campti. Louisiana
NDC pulp washer
gauge can save
$300,000 annually
Optimized pulp
cleaning takes
discipline,
organization
Han, Yushan and
Edwards, Lou
Bender, Greg,
Richard, Larry,
and Dorn, Walt
Hagen, Nils and
Berg, Jan-Erik
Histed, J.A. and
Cenovas, R. Vega
TAPPI Journal, June
1988, pp. 101-104
TAPPI Journal,
December 1988, pp.
115-118
TAPPI Journal, June
1989, pp. 93-96
TAPPI Journal, March
1988, pp. 157-160
Sende, U.E.,
Oestreich, H.A.,
Poplasky, M.S.,
and Stewart,
J.R.
Morgan, Larry
Franko, Andrew,
and Talbert,
Ronald
TAPPI Journal, March
1988, pp. 93-97
PIMA Magazine,
August 1988, p. 30
PIMA Magazine, March
1988, p. 21
PIMA Magazine,
February 1988, pp.
29-30
To minimize total dissolved solids carryover from brownstock washing
for a given shower flow, drun vacuum is the most important operating
variable.
The control strategy, based on a mathematical model, has reduced
process variations and carryover of black-liquor solids. Mill
productivity has increased by 10X since the system was started up.
The ratio between washing time and dewatering time on a flat band
washer is proportional to a permeability constant times the ratio of
wash liquor volume to fjltrate volume in the dewatering zone.
Up to 94X of the lignin that can be removed in the first caustic
extraction stage of a conventional process can be removed rapidly from
well-chlorinated pulp with two countercurrent displacements with
caustic. The time per displacement can be as short as 1.7 s. A
slight loss in extraction efficiency is more than made up by improved
washing efficiency. On a conroercial scale, the chlorinated pulp can
be formed into a sheet, washed, extracted twice, and washed three
times on a six-stage horizontal washer. Caustic requirements are 2.3
that of a conventional extraction. Energy requirements are lower than
in a conventional bleachery. This technology also presents an
opportunity to lower the capital cost of a bleachery.
Simple, low-cost, automated shower-water control systems on two
unbleached-stock washer lines have provided substantial savings in
evaporator steam, chemicals, and secondary treatment costs.
Larry Morgan describes another means to conserve energy by the proper
selection of a washing system in a linerboard mill upgrade.
10
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
PULP WASHING
NUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
3.23 Some bleach plant
modifications to
reduce the amount of
toxic substances in
pulp and filtrate
3.24 Effects of
brounstock Mashing
on the formation of
chlorinated dioxtns
and furans during
bleaching
3.25 New pressurized
compaction filter
lowers operating and
capital costs
3.26 Brownstock showers
reduce dioxin and
more
3.27 Efficient post
oxygen washing -
crucial for low
bleach plant
emissions
Edwards, L.,
Myers, M., and
McKean, B.
Hise, R.G.,end
Hintz, H.L.
Tait, D.
Reynold, G.
Lindstrom, L.A.,
and Norden, S.
TAPPI Seminar
Proceedings,
Bleaching and the
Environment,
Seattle, Washington,
September 1988, pp.
328-332
TAPPI Journal,
January 1990, pp.
185-190
This report discusses the benefits of increasing the amount of lignin
removed from the brownstock pulp through more efficient washing.
Pulp & Paper,
November 1985
CPPA Proceedings,
76th Annual Meeting
Technical Section,
Montreal, Quebec,
February 1-2, 1990,
pp. A237-A240
APPITA 1990
Conference, New
Zealand, April 1990
Poor brownstock washing ted to increased levels of PCDDs and PCDFs in
softwood pulps after chlorination stage and in the final effluent.
Additional washing in the laboratory with copious amounts of aqueous
ethanol decreased chlorinated dioxins and furans by 80X. These
results demonstrate the presence of solvent-extractable precursors for
PCOD/Fs associated with this unbleached pulp. Also found that spiking
unbleached pulp with higher than normal levels of defoamers used had
no significant effect on the formation of PCDD/Fs after bleaching.
Pulp washer with compaction baffle and pressurization permits low-
level installation, lower power consumption, and greater efficiency.
Dioxin generation and soda loss can be reduced through improved
brownstock washing. The most economical way to achieve this improved
washing is through the proper application of the shower filtrate.
This paper will discuss the characteristics of he state-of-the-art
shower pipe system, a case history on improved washing through the use
of this system, and the effect of shower performance on the reduction
of dioxin.
Oxygen delignified pulp with a Kappa number of 17.7 was bleached in a
C50/D50EoD sequence. Wash losses, measured as COD, were varied from
0-20 kg/bdt. At optimum bleaching conditions, the incremental
increase of active chlorine due to increased carry-over was estimated
at 0.5-0.6 kg act. Cl/bdt. AOX discharge increased about AOX at 20 kg
COO/bdt compared with completely washed pulp. The sum of tri- and
tetra-chlorophenotic compounds formed during bleaching, was roughly
doubled at a high wash loss compared with completely washed pulp.
11
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
BLEACHING
NUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
4.0 BLEACHING
4.1
4.2
4.3
4.4
4.5
How bleaching
hardwood kraft pulp
with oxygen affects
the environment
Substituting
chlorine dioxide for
chlorine
Factors that affect
the generation of
chloroform in
bleaching
Chlorinated organic
matter in bleached
chemical pulp
production
Hinimizing the
formation of
chlorinated organic
material through
controlled
chlorination in the
production of high
quality softwood
kraft pulp
Jones, A.R.
TAPPI Journal,
December 1983, pp.
42-43
Pyrke, Douglas
C.
Crawford, Robert
J., and Stryker,
Hargeret N.
TAPPI Journal,
October 1989, pp.
147-155
TAPPI Journal,
November 1989, pp.
151-159
Earl, Paul
and Reeve,
Douglas U.
TAPPI Journal,
October 1989, pp.
183-187
Armergren, G.
Rees-Anderson,
A.M., and
Lindblad, P.O.
TAPPI Proceedings,
April 1987
Environmental
Conference, pp. 313-
318
We have found the environmental impact of oxygen-bleached hardwood
kraft pulp to compare favorably with that of an existing CEDED
sequence. First, the effluent volume can be reduced to 4,000 gal/ton.
Second, the B006 loss is only 2.3 that of the conventional CEDED line.
Third, effluent color is only 15X of the color load from the more
conventional process. Because of its low environmental impact, and
OC/DED bleach sequence is the process we have selected for our new
greenfield mill at Eastover, South Carolina.
Increasing chlorine dioxide substitution minimizes bleaching chemical
consumption, decreases bleaching costs, and improves bleach plant
effluent quality. It also minimizes the formation and discharge of
chlorinated organic compounds.
Bleachery filtrate mixing and pH adjustment in the mill effluent
treatment system affect the formation of chloroform. In laboratory
experiments, the pH adjustment of chlorination-stage filtrate resulted
in chloroform generated through this process will depend on the
specific bleaching conditions in the chlorination-stage and on the pH
of the combined mill sewer. In some cases, this effect may account
for a significant fraction of the chloroform in the influent to
wastewater treatment systems.
Softwood kraft pulps were chlorinated at low and medium consistency in
the laboratory, covering a wide range of chlorination levels, with and
without chlorine dioxide substitution. The filtrates from the
chlorination and extraction stages were analyzed for organically bound
chlorine (AOX) and solvent-extractable organically bound chlorine
(EOX). AOX formation decreased when mixing was improved but EOX was
unchanged. Consistency had little effect. At SOX chlorine dioxide
substitution in the C stage, (C+E)-stage AOX formation fell by 40X.
AOX and EOX formation were proportional to the amount of elemental
chlorine in the chlorine and chlorine dioxide consumed. AOX and EOX
formation increased dramatically with extensive delignification.
Equations were developed to estimate the amount of AOX and EOX formed,
based on the elemental chlorine in the oxidant consumed by the pulp.
Spent liquors from the chlorination and alkali extraction of an oxygen
prebtcached softwood kraft pulp were investigated with respect to
environmental papermeters such as TOCl, chlorinated phenolic compounds
some of which are lipophilic, other lipophilic compounds and
mutagenicity. The chlorine ratio (X available chlorine/Kappa number)
was varied within the range of 0.05 and 0.5. In some experiments,
chlorine was partially substituted for chlorine dioxide. The results
show that the parameters vary considerably with variations in the
chlorine ratio and that therefore possibilities exist to minimize
chlorinated organic compounds through controlling the chlorination.
12
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
BLEACHING
MUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
4.6
4.7
4.8
4.9
4.10
Effect of brownstock
Mashing on formation
of chlorinated
dioxins and furans
during bleaching
Impact of high
chlorine dioxide
substitution for
chlorine on the
oxygen delignified
pulp at Espanola
Influence of
chlorine ratio and
oxygen bleaching on
the formation of
PCOFs and PCDDs in
pulp bleaching
Reinforcement of
oxygen-aIkali
extraction with
hydrogen peroxide or
hypochlorite
The fraternity
gathers at the
chateau: the 1985
International Pulp
Bleaching Conference
Hise, R. and
Hintz, H.
Munro,
Chandrasekaran,
Cook and Pryke
Rappe.
Christopher, and
Glas, Bo
TAPPI Press,
Environmental
Issues: An
Anthology of 1989,
pp. 123-129
TAPPI Press,
Environmental
Issues: An Anthology
of 1989, pp. 187-198
TAPPI Journal, April
1989, pp. 147-153
Bourson, L.,
Lachenal, D.,
and de Choudens,
C.
TAPPI Journal, July
1986, pp. 90-93
Pyrke, Douglas
C.
TAPPI Journal.
August 1985, pp.
145-147
The effect of brownstock washing on formation of polychlorinated
dlbenzo-p-dioxins (PCDDs) and furans (PCDFs) was evaluated in
laboratory studies and mill trials. Poor brownstock washing led to
increased levels of these materials in softwood pulps after the
chlorination stage and in the final effluent.
With the prime objective of eliminating polychlorinated dioxins and
furans in the bleached pulp and effluent, E. B. Eddy Forest Products
Ltd. at Espanola embarked on a mill trial to increase the chlorine
dioxide substitution level in the softwood chlorination stage from 10X
to SOX of the total equivalent chlorine applied. OCDE0HD is the
bleaching sequence used. Four levels of substitution were studied
with respect to their impact on pulp quality, effluent characteristics
and bleaching cost.
In a laboratory bleaching study, we assessed the influence of the
chlorine ratio and oxygen bleaching on the amounts of polychlorinated
dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs)
formed. A significant factor affecting the amounts of PCDF and PCDD
is the chlorine ratio. On well-washed laboratory pulp, oxygen
bleaching has little or no effect. The beneficial effect of oxygen
bleaching on the amounts of PCDFs and PCDDs observed in mill-scale
studies is therefore likely the result of the much greater efficiency
in pulp washing through the oxygen bleaching stage.
Small amounts of hydrogen peroxide or hypochlorite (up to 5 kg/metric
ton of pulp) were added in the oxygen extraction stage of various
bleaching sequences: C/DEgDED, C/DE,,D, CE0HD, and OC/DEoD. Two kg of
Hj02/metric ton of o.d. pulp made it possible to save up to 3.5 kg of
ClOj/metric ton of o.d. pulp. With 5 kg of NaOCl added, the additional
Cl02 reduction attained was 5 kg/metric ton of o.d. pulp. The effect
of 02 and H202 or NaOCl was roughly additive. Also, it is better to
introduce HJ02 'n t*le Eo stage of an OC/DEoD sequence than in the
oxygen stage. Experiments carried out on three different pulps showed
that the advantages imparted by E0 (i.e. reduction of the operating
cost, improvement of pulp viscosity, opportunity of shortening the
bleaching sequences, and the possibility of increasing the pulp
output) are enhanced by combining HJ02 or Hypochlorite with oxygen.
13
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
BLEACHING
NUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
4.11
4.12
4.13
Pretreatment of
kraft pulp Is the
key to easy final
bleaching
Chlorinated organic
matter in bleached
and chemical pulp
production
Fossum, M., and
Harkluod, Ann
Earl, Paul f..
and Reeve,
Douglas U.
TAPPI Journal,
November 1988, pp.
79-84
TAPPI Journal,
January 1990, pp.
179-183
Oxygen bleaching of
kraft pulp: high
consistency vs.
medium consistency
Idner, Kristina
TAPPI Journal,
February 1988, pp.
47-51
Low values of total organic chlorine (0.5 kg/metric ton) were reached
with a combination of extended dilignification to Kappa numbers below
10 and a high chlorine dioxide fraction in the prebleaching,
Fifty percent chlorine dioxide substitution decreased the total amount
of chlorinated phenolic compounds and the amount of tri- and
tetrachlorinated phenolic compounds in chlorination and extraction
stage effluents. Improved chlorination stage mixing also decreased
the formation of tetrachlorinated phenolic compounds. Increased
consistency showed no increased consistency resulted in a decrease in
the total amount of chlorinated phenolic compounds. Chloroform
formation in the chlorination stage was decreased by improved mixing,
by increased consistency, and by 50% chlorine dioxide substitution.
Pulp viscosity at a given degree of delignification is slightly higher
for medium consistency bleaching than for high-consistency oxygen
bleaching.
4.14
4.15
4.16
Reactions of
nitrated kraft
lignin in an
alkaline oxygen
bleaching stage
Lindeberg, Otto,
and Welding, Jan
TAPPI Journal,
October 1987, pp.
119-123
Substituting
chlorine dioxide for
elemental chlorine
makes the bleach
plant effluent less
toxic
Effects of oxygen
extraction on
organic chlorine
contents in
bleaching plant
effluents
Axegard, Peter
Hong, P., Shin,
Nam Nee, and
Chang, Hou-min
TAPPI Journal,
October 1986, pp.
54-59
TAPPI Journal, June
1989, pp. 157-162
Pretreatment of kraft pulp with N02/0, under acid conditions allows for
an extended delignification in a following oxygen bleaching stage
without extensive loss of viscosity. To find an explanation for the
beneficial effect of the pretreatment, experiments with nitrated kraft
lignin and nitrated lignin model compounds of the nonphenolic, B-aryl
ether type have been carried out. The results show that the presence
of nitrated lignin in the oxygen bleaching of softwood kraft pulp
leads to a decrease in carbohydrate depolymerization. Furthermore,
nitration of aromatic nuclei in the tignin results in faster alkaline
hydrolysis of aldyl aryl ether bonds. The combination of these
effects may provide an explanation for the increased selectivity
(viscosity at a given Kappa number) obtained with an N02/02
pretreatment.
A full scale mill trial shows there are two principal ways of reducing
the consumption of elemental chlorine by using more chlorine dioxide
when bleaching to full brightness.
An unbleached kraft pulp and an oxygen-prebleached kraft pulp were
chlorinated at various chlorine dosages. The chlorinated pulps were
extracted under conditions for alkaline extraction (E and oxygen-
alkali extraction (EO).
14
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
BLEACHING
NUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
4.17 Low AOX,
possibilities and
consequences
4.18 Environmental
compatible bleaching
of chemical pulp
4.19 Manufacture of
bleached aspen
market pulp without
the use of chlorine
or chlorine dioxide
4.20 High efficiency
chlorine dioxide
bleaching
4.21 Peroxide bleaching
reduces dioxin
formation
4.22 Cost effective AOX
reduction
Basta,
Holtinger, Nook
and Lundgren
Brunsvik,
Grundelius,
Kordes and Swan
Ng. D., Tichy,
J., and Wong, A.
Seger, Chang and
Jameel
Reid, Billmark
and Sutton
Cook, Eagle and
Gough
TAPPI Press,
Environmental
Issues: An
Anthology of 1989,
pp. 139-148
TAPPI Press,.
Environmental
Issues: An
Anthology of 1989,
pp. 149-152
TAPPI Press,
Environmental
Issues: An
Anthology of 1989,
pp. 199-202
TAPPI Press,
Environmental
Issues: An
Anthology of 1989,
pp. 211-217
TAPPI Notes, Oxygen
Delignlfication
Symposium, 1990, pp.
85-89
TAPPI Notes, Oxygen
Delignification
Symposium, 1990, pp.
91-99
Various laboratory and mill experiments were carried out using oxygen-
prelignified, kraft softwood pulp in an effort to lower the AOX level
through the reduction or elimination of chlorine in the bleaching
sequence. This must be achieved in a way which is as cost-effective
as possible, while still maintaining a high brightness in a high
quality pulp. The possibilities and consequences of the three
different approaches will be discussed.
This paper deals with the problems of minimizing the formation of
chlorinated organic compounds during the bleaching process. It points
out the different measures taken in the Store Cell mills to reduce
chlorination of organic substances and clarifies the consequences for
the pulp quality. Finally, some of the chlorinated organic compounds
in the effluent discharge are identified or characterized.
The neutral sulphite-anthraquinone (NSAQ) process can be used to
produce a high-yield and high-brightness pulp from aspen wood.
Bleaching of this NSAQ aspen with oxygen and hydrogen can yield a 85+
pts brightness pulp. The use of C12 and Cl02 is not required.
Physical properties of the 02/H20 bleached aspen NSAQ pulp are
comparable to those of conventional bleached aspen kraft pulp.
A process to improve the efficiency of chlorine dioxide bleaching has
been developed to produce pulps with higher brightness at equal
chlorine dioxide usage.
This paper describes the effect that peroxide has on discharges,
operations, and pulp quality. Hydrogen peroxide may be used in the E0
stage to reduce the chlorine required in the CD stage.
The addition of peroxide to the oxygen reinforced caustic extraction
stage can reduce the quantity of chlorine and hypochlorite used in the
chlorination stage giving a significant reduction in AOX discharge at
break-even cost. The effectiveness in the mill was found to be
greater than could be measured in laboratory testing. The addition of
oxygen and caustic soda to the brown stock entering the bleach plant
can also give a significant reduction in AOX discharge via the reduced
use of active chlorine in the chlorination stage. This process is
capable of giving a reduction in the total bleaching cost and can be
installed at low cost with a rapid pay-back time.
15
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
BLEACHING
NUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
4.23
4.24
4.25
Hydrogen peroxide
reinforced
extraction lowers
chlorinated organics
and color in bleach
plant effluent
Chlorinated organic
matter in bleached
pulp • effect of
important process
variables
Overview of emerging
technologies in
pulping and
bleaching
Klein, Meng,
Jameel and
Sundaram
Annergren,
Osterberg and
Linblad
Bowen and Hsu
TAPPI Proceedings,
Pulping Conference
Book 2, 1990, pp.
829-835
TAPPI Press,
Environmental
Issues: Anthology
of Published Papers,
1990, pp. 27-36
TAPPI Press,
Environmental
Issues: Anthology
of Published Papers,
1990, pp.69-84
The capability of hydrogen peroxide and oxygen in the E, stage to
produce pulps of low Kappa factors while maintaining good pulp quality
was examined in laboratory studies and mill trials.
The objectives in the first part of our studies were to control the
brightness reversion in a kraft mill producing bleached birch pulp by
achieving a low EOCl level in the pulp. The second part of the study
has been a laboratory investigation of both the non-extractable OCl
and EOCl of softwood and birch kraft mill pulps.
This article provides an overview of extended detignification
technologies, including cold blow cooking, rapid displacement heating
and modified continuous cooking, oxygen delignification, high chlorine
dioxide substitution, split addition of chlorine/pH control, E0 and Eop
extraction and non-chlorine bleaching.
4.26
4.27
4.28
Evolution of bleach
plant design
practice to minimize
environmental impact
Pirsonite deposits
in green liquor
processing
The recycling of
acidic bleach plant
effluents and their
effect on preparing
white liquor
Shackford, L.
Frederick, Jr.,
U.J., and
Krishnan, Rajeev
TAPPI Press,
Environmental
Issues: Anthology
of Published Papers,
1990. pp. 180-188
TAPPI Journal,
February 1990, pp.
135-140
Teder, Ants,
Anersson, Urban,
Littecke,
Katarina, and
Ulmgren, Per
TAPPI Journal,
February 1990, pp.
113-120
This report presents an overview of areas of focus for bleach plant
effluent control.
Pirssonite deposits are a persistent problem in green liquor
processing. The extent of this problem is related to the solubility
behavior of pirssonite, but it also depends on the design of the green
liquor process equipment and control system. Perssonite deposits form
at total titratable alkali (TTA) concentrations that correspond to the
solubility limit for Na2COj in sodium salt solutions when CaC03 is
present. Ineffective mixing in the dissolving tank also can
contribute to the problem. Perssonite deposits can be minimized by
keeping the average TTA below 90X of the TTA at perssonite saturation,
controlling TTA variability, allowing some lime mud to be carried over
with the weak wash, minimizing the calciun input to the soda cycle,
providing adequate mixing for the dissolving tank, maintaining a high
green liquor temperature throughout the process, and providing
positive flow in green liquor lines where stagnation or low flow can
otherwise occur.
The impact of chlorinated compounds could be reduced if the acidic
effluent from the pre-bleaching stage was used to wash the pulp before
bleaching and then used in preparing the white liquor.
16
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
BLEACHING
MUHBER
TITLE
AUTHOR
REFERENCE
4.29
4.30
4.31
4.32
4.33
Technologies for
reducing dioxin in
the manufacture of
bleached wood pulp
U.S. Congress
Office of
Technology
Assessment
Dissolution of
lignin from kraft
pulp after treatment
with nitrogen oxides
Chang, Yu, and
Eckert
Effect of alkaline
extraction of ozone-
bleached pulp on
brightness and
bleachability
Undholm, C.A.
P&P's annual
bleaching survey:
capital expenditures
increasing
Oxygen bleaching
practices and
benefits - an
overview
Ducey, M.J.
Tench, I, and
Harper, s.
OTA-BP-0-54,
Washington, DC, U.S.
Government printing
office. May 1989
Journal of Wood
Chemistry and
Technology, 1990,
pp. 311-330
Journal of Pulp and
Paper Science,
November 1990, pp.
190-195
TAPPI Proceedings,
International Pulp
Bleaching, June 1988
TAPPI Proceedings,
1987 International
Oxygen
Delignification
Conference
Alternative technologies using oxygen as a pretreatment to chlorine
bleaching and improved delignificat ion that removes more of the
potential reactants from the wood can reduce the amount of dioxin in
bleached pulp. Substituting other bleaching chemical for chlorine
also shows promise for reducing the amount of dioxin produced in the
bleaching process should regulation be required. This study provides
an assessment of these technologies: it does not address the policy
issues related to regulating dioxin in paper products and controlling
environmental release.
Laboratory experiments show that pretreatment with N02> including
heating and ripening at 5X consistency and 90°C for 3 hours in the
presence of NOy and H+ led to a dissolution of approximately 50-60X of
the lignin in unbleached kraft pulp. Only 5-1SX were dissolved when
the treatment was terminated after heating to 90°C. An extensive
fragmentation of the lignin during the ripening explains the extensive
delignificat ion in acid medium. Fractionated dissolution of the
remaining lignin by alkaline extraction gave fractions with small
variation in N-contents (2.9-3.4X) and hydrophilicity. The last
fraction exhibited the highest sorption of water vapor. The
deUgnif icatfon was related to the decrease in molecular size during
the pretreatment end during subsequent alkaline treatments.
The effect of alkaline extraction on the brightness and bleachability
of ozone and oxygen-ozone bleached softwood kraft pulp was
investigated. Ozone bleaching reduces the light absorption
coefficient linearly as a function of the Kappa number. Alkaline
extraction increases the light absorption coefficient by
1.3...2.0m2/kg, if compared at a certain Kappa level. As a result, ZE-
and OZE- bleached pulps are 4...9 brightness units darker than
corresponding Z- and OZ- bleached pulps. Alkaline extraction also
reduces the brightness level that can be attained in a subsequent
chlorine dioxide stage if starting from a certain Kappa level.
Discussion of control system for oxygen delignification based on on-
line Kappa number measurement. System reduced average Kappa number
and production costs.
A list of the world wide oxygen delignification installations and a
summary of the experience gained to date are presented. Pulp quality,
environmental benefits, chemical savings, the impact on recovery and
energy consumption, high vs. medium consistency delignification and
washing and screening considerations are discussed.
17
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
BLEACHING
NUMBER
TITLE
AUTHOR
REFERENCE
4.34
4.35
4.36
4.37
Effect of
prebleaching
conditions on the
performance of short
sequences for oxygen
bleached kraft pulp
Pulping bleaching
concerns focus on
CtOj generation,
effluent
Chlorine dioxide
substitution reduces
the load of TOCl
Influence of
bleaching chemicals
and lignin content
on the formation of
polychlorinated
dioxins and
dibenzofurans
Annergren, G.E.,
lindstrom, L.A.,
Lindbled, P.O.,
and Norden, S.
TAPPI Proceedings,
International Pulp
Bleaching
Conference, June
1988, pp. 37-46
Ducey, M.J.
Axegard, P.
Axegard, P., and
Renberg, L.
Pulp & Paper, June
1987, pp. 89-92
TAPPI Proceedings,
Pulping Conference,
November 1987, pp.
105-110
Chemosphere, (Dioxin
88)
Important prebleach ing conditions have been studied for short sequence
bleaching both in the laboratory and in mills. The studies concerned
mainly oxygen bleached kraft pulp but certain comparisons have been
made with unbleached kraft pulp. There were two reasons for dealing
with prebleaching in this case. A short sequence gives higher
weighting to each stage which calls for a particular optimization of
the prebleaching. On the other hand, environmental concerns aim at a
low formation of chlorinated organics through a reduced chlorination.
The general opinion is that a high chemical charge is required in the
chlorination of a short sequence. However, our results indicate that
this is not true for normal levels of final brightness and that
commercial operation with a substantial restricted chlorination is
possible. The reinforcement of the alkaline extraction is very
important in this context.
Article takes a comprehensive look at the current mill chemical
consumption patterns, new supplier products and their markets and the
latest developments from a number of North American research
institutions, and provides some brief facts on worldwide chemical pulp
production and growth over the past 12 months.
Laboratory bleaching experiments have been carried out on an
industrial oxygen delignified softwood kraft pulp at different Cl02 -
substitution levels. Parameters studied were prebleaching efficiency,
final brightness, formation of chlorate as well as chlorinated
organics. The formation of TOCl, EOCl, AOX, highly chlorinated
phenolics and chloroforms is reduced with reduced C12 consumption.
The determination of chlorinated dibenzo-p-dioxins and dibenzofurans
in pulp and aqueous filtrate from pulp bleaching showed that the most
important variable is the consumption of molecular chlorine (C12)
expressed as the ratio between chlorine and the lignin content (ClH-
multiple). The formation of the dioxins and dibenzofurans increased
drastically above a certain critical level end below this level the
formations were very low. No significant difference between oxygen
dilignified and non-oxygen delignified softwood kraft pulp could be
established.
4.38
4.39
Results of on- site
pilot plant studies
of the SLC
Extraction Process
Use of hypolite
bleach in short
sequence pulp
bleaching
Elton, E.F.;
Parkinson, J.R.
Hurst, H.H.,
Sturik, T.S.,
and Duff, A.
TAPPI Proceedings,
1987 Pulping
Conference, pp. 673-
678
TAPPI Proceedings,
1987 Pulping
Conference, pp. 15-
19
The SLC (suppressed lignin condensation) extraction process was pilot
tested on hardwood and softwood kraft pulp in two separate mills.
Reported results were decreased CEK nunfcer and decreased steam,
hypochlorite (47X), and chlorine (10X) usage.
Paper discussed brightness, viscosity ad chloroform formation when
replacing peroxide or hypochlorite with hypolite bleach, during pulp
bleaching.
18
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
BLEACHING
MUHBER
1.40
4.41
4.42
4.43
4.44
4.45
4.46
4.47
Efforts in chemical
pulp bleaching
technology emphasize
cutting costs
Curtailing dioxin
formation-
ramifications for
chemical pulp
bleaching
Oxygen bleaching
processes
Complete effluent
recycling in the
bleach plant with
ultrafiltration and
reverse osmosis
Toward preventing
the formation of
dioxins during
chemical pulp
bleaching
Oxidative
bleaching - a
review, part I:
detignificatlon
Worldwide E0
Installations survey
The'future of
bleaching
AUTHOR
Ducey, H.J.
Berry, R.M., et
al.
McDonough, TJ.
Dorica, J, Wong,
A., and Garner,
B.C.
Dorica, J.,
Wong, A., and
Garner, B.C.
REFERENCE
Pulp & Paper, July
1986, pp. 47-50
Dioxin '89,
September 1989
TAPPI Journal, June
1986, pp. 46-52.
TAPPI Proceedings,
1985 Pulping
Conference, p. 590
TAPPI Proceedings,
1985 Pulping
Conference, p. 590
SYNOPSIS
Liebergott, N.,
and van LIcrop,
8.
Reeve, D.W.
Reeve, D.W.
Pulp & Paper Canada,
September 1986, pp.
58-62
TAPPI Journal,
November 1985, pp.
142-143
TAPPI Journal, June
1985, pp. 34-37
Article presents a sunmary of Pulp & Paper's third annual survey of
bleaching equipment. Finds fewer new systems; emphasis is on washing,
process control, chemical additions. Oxygen delignification is the
number one choice of mills installing new systems.
Paper discusses many aspects of oxygen delignification, high and
medium consistency, selectivity and protectors, pretreatment with
nitrogen oxides, and process fundamentals. Also discusses oxygen
extraction and low-pressure oxygen bleaching.
A membrane filtration process was studied for the treatment of bleach
plant effluents using ultrafiltration and reverse osmosis. The
objective was removal of color, organic compounds, and chloride ions.
The filtration process design and costs are presented.
Suitable combinations of chlorine multiple and CL02 substitution which
lead to low or undetectable levels of TCDD and TCDF have been found to
be more effective than the reverse mode of addition for reduction of
chlorinated dioxins and furans. Increasing the C-stage pH and
decreasing its consistency also appears to be beneficial. Minimizing
the levels of the precursors, dibenzodioxin (080) and dibenzofuran
(D8RF), was confirmed as being important for curtailing TCDD and TCDF
formation. In particular, oxygen delignification was found to be
advantageous, not because it removes Ugnin but because it decreases
the precursor levels.
Literature relating to the use of oxidative chemicals in the
delignification and brightening operations of pulp bleaching is
reviewed. Experimental data on the use of oxygen, ozone and chlorine
dioxide In the chlorination stage, end hypochlorite, peroxide and
oxygen in the extraction stages are also presented.
World wide survey of E0 (use of oxygen in the extraction stage of
chemical pulp bleaching) installations.
Sunnary of what is taking place in bleaching, what are the economic
influences and what is predicted to happen in the near future.
19
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
BLEACHING
IIUfBcR
TITLE
AUTHOI
REFERENCE
SYNOPSIS
4.48
4.49
4.50
4.51
4.52
4.53
Oxidative extraction
at Halsey Mill cuts
hypochlorite
consumption
Tutorial - non-
chlorine bleaching
of chemical pulp
4.54
Final bleaching of
kraft pulps
delignified to low
Kappa number by
oxygen bleaching
Short sequence
bleaching with
oxygen: part II
Automated Cl02
generation improves
bleaching, cuts
effluent
Technical
'consequences of new
knowledge on
prebleachIng with a
high fraction of
chlorine dioxide
Oxygen bleaching
system operating
well at Union Camp's
Franklin Hill
Ducey, M.J.
Liebergott, N.,
van Lierop, B.,
Garner, B.C.,
and Kubes, G.J.
Fossun, G.,
Lindqvist, B.,
and Persson,
I.E.
Schleinkofer,
R.U.
Evans, J.C.U.
Germgard, If.
Pulp & Paper,
October 1984, pp.
118-119.
TAPPI Proceedings,
1987 Environmental
Conference, pp. 303-
312
Smith, K.E.
TAPPI Journal,
December 1983, pp.
60-62
TAPPI Proceedings,
1982 Pulping
Conference, pp. SOS-
SOS
Pulp & Paper,
February 1983, pp.
69-71
TAPPI Journal,
December 1982, pp.
81-83
Pulp & Paper,
October 1982, pp.
90-93
Discussion of how an oxidative extraction system having a high-shear
mechanical mixer repaid its capital costs within one year. System
installation considered a success.
Two bleaching sequences were developed for a kraft pulp (Kappa #30.6)
that avoid chlorine-containing compounds by using only oxygen (0),
ozone (Z), sodium hydroxide (E), hydrogen peroxide (P), and sodium
hydrosulphite (Y). Effluents were 40-60% lower in color than those
obtained from a conventional C/DEOED sequence. The oxygen stage may
be done at medium (7X) or high (25%) consistency. After the sequence
OZEP, the pulps had a brightness of 80-86X ISO. In the sequence ZOP,
the final brightness could be improved by 10 points if the ZO bleached
pulps were washed with effluent from the Z stage. Semi-bleached pulps
from both sequences achieved a brightness of 88-90% on final-stage
bleaching with hydrosulphite. The strength properties of pulps
bleached by these novel sequences and by conventional C/DEDED, OZEPY
and ZOPY sequences was evaluated.
Discussing of pretreatment kraft pulp with nitrogen dioxide and oxygen
prior to oxygen bleaching. Chemical demand, pulp viscosity, strength
and yield and bleach effluents from pretreated sequence is compared to
conventional oxygen bleaching.
Laboratory bleaching data from the sequences C/D-E-D-E-D, 0-C/D-E-D,
C/D-E-Eo-D, 0-C/D-Eo-D, and C/D-Eo-0-E-D are compared for two softwood
kraft pulps. Costs, Kappa number, viscosity, brightness, energy
consumption, and effluent properties are compared.
Discussion of continuous monitoring and control for a chlorine dioxide
generator.
Prebleach ing of softwood kraft pulp with chlorine dioxide and low
fraction of chlorine has been studied in the laboratory under well-
controlled bleaching conditions. This paper concentrates on the
influence of the chlorine fraction and of a preceding oxygen bleaching
stage. The technical consequences are discussed, particularly for the
case where an oxygen bleaching stage precedes a pure chlorine dioxide
prebleaching stage.
Overview of oxygen bleaching system at Union Camp's Franklin mill.
Process is a four stage OC/DED sequence reporting a reduced chemical
and water usage and improved effluent treatment.
20
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
BLEACHING
NUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
4.55 Bleaching technology
review: recent
developments, future
trends
4.56 Relative rates of
consumption of
chlorine and
chlorine dioxide
during (0+C)
bleaching of
softwood kraft pulp
4.57 Short sequence
bleaching with
oxygen: part I
4.58 Developments in
chlorine dioxide
bleaching
4.59 Medium-consistency
oxygen bleaching -
an alternative to
the high-consistency
process
4.60 Oxygen bleaching
shows potential for
reducing costs and
effluent problems
4.61 Oxygen bleaching
shows potential for
reducing costs,
effluent problems
4.62 Mill experience with
oxygen and hydrogen
peroxide bleaching
stages
Macleod, M.
Gertngard, U.,
Teder, A, and
Tormund, D.
Schleinkofer,
R.U.
Pulp ft Paper,
October 1982, pp.
61-65
TAPPI Journal, May
1982, pp. 124-126.
Pulp & Paper Canada,
83:11 (1982)
Reeve, D.W., and TAPPI Journal,
Rapson, W.H. September 1981, pp.
141-143
Nalman, I.E.,
and Annergren,
G.E.
Chang, H.M.
Almberg, I.,
Jamieson, A.,
and Ualdestam,
S.
Helmling, 0.,
Suess, J.U..
Meier, J, and
Berger, M.
TAPPI Journal, April
1980
Pulp & Paper, March
1980, pp. 87-91
Pulp & Paper, March
1980, pp. 92-95
TAPPI Journal, July
1989, pp. 55-61
Discussion of chlorination issues, chlorine free bleaching, sequence
modifications, optimizing sequences without oxygen and displacement
bleaching, and closed cycle systems. Total organic chloride generated
by various sequences is presented.
Experiment presenting the relationship between consumption of chlorine
dioxide and chlorine during (D&C) bleaching.
Two unbleached kraft pulp samples, one hardwood and one softwood,
produced by two eastern Canadian mills, were bleached in the
laboratory by the sequences C/OEDEO, OC/OEO and OC/DEoD. Fully
bleached pulps of 90 ISO brightness were obtained with the sequence
OC/OEoO at substantial savings in chemical cost compared to sequence
C/DEDED, and strength properties were almost identical. Energy
balances show very small differences in net steam and power demand.
Discussion of increased replacement of chlorine by chlorine dioxide in
the first stage, Dc-C serial bleaching, and chlorine in chlorine
dioxide bleaching. A comparison of bleaching sequences with respect
to chemical usage, energy required, and inflation of chemical and
energy costs is provided.
Medium-consistency oxygen bleaching has been examined both in the
laboratory and on a pilot-plant scale and has been found to give very
encouraging results in terms of delignification and chemical
consumption. Discussion of the laboratory and pilot plant studies and
commercial application is provided.
Discussion of the oxygen bleaching process, advantages and
disadvantages, new processes being implemented, dissolved oxygen
displacement delignification process (DODEL), and low and medium-
consistency oxygen bleaching.
Capital and operating costs, energy consumption, and degree of
pollutant reduction are compared for oxygen bleaching and biological
treatment.
Discussion of using hydrogen peroxide in both delignification and
extraction stages of bleaching and of reinforcing stages with oxygen
and hydrogen peroxide. Reinforcing the £0 stage with hydrogen
peroxide (EOP) is economical and gives better pulp qualities. HOP can
be used efficiently as a first bleaching stage in sulfide pulp mills.
21
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
BLEACHING
NUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
4.63
4.64
4.65
4.66
4.67
4.68
Split addition of
chlorine and pH
control for reducing
formation of dioxins
Bleaching and the
environment
Influence of
chlorine ratio and
oxygen bleaching on
the formation of
PCDFs and PCDDs in
pulp bleaching. Part
2: a full mill study
Bleaching and the
environment
Oxygen bleaching,
today's standard for
pollution
abatement - PRENOX
next to come?
Direct biological
bleaching of
hardwood kraft pulp
with the fungus
coriolus versicolor
Hise, R.G.
Kringstad, K.P.,
de Sousa, F.,
Johansson, L.,
Kolar, H.C., and
Swanson, S.E.
Kringstad, K.P.,
Johansson, L.,
Kolar, M.C., de
Sousa, F.,
Swanson, S.E.,
Glas, B., and
Rappe, C.
Kringstad. K.P.,
and Lindstrom,
K.
Lindblad, P.,
and Norden, S.
Paice, M.C.,
Jurasek, L., Ho,
R., Bourbonnais,
R., and
Archibald, F.
TAPPI Journal,
December 1989, pp.
121-126
Addendum to paper
presented at the
TAPPI/CPPA 1988
International Pulp
Bleaching
Conference, Orlando,
Florida, June 1988.
TAPPI Journal, June
1989, pp. 163-170
TAPPI Proceedings,
1988 International
Pulp Bleaching
Conference, Orlando,
Florida
The Fifth Technical
Seminar at Sunds
Defibrator
Proceedings,
Sundsvail, June
1988.
TAPPI Journal, May
1989, pp. 217-221
Process modifications in the chlorination stage produce high
brightness, high viscosity pulps with dramatically reduced levels of
2378-TCDD and 2378-TCDF, and can be implemented faster and more
economically than other techniques.
Paper discusses the formation of dioxins in the kraft bleaching
process and measures to decrease or eliminate such formation.
We studied the effect of low-chlorine bleaching on the formation of
polychlorineted dibenzofurans and polychlorinated dibenzo-p-dioxins
(PCDFs and PCDDs) in full mill-scale experiments. An oxygen-bleached
softwood kraft pulp with a Kappa number of 19.5 was bleached using
33.3 kg of C12 and 6.2 kg of ClO, per ton of pulp in the first stage.
A similar pulp was bleached using a mixture of 19.3 kg C12 and 12.5
Cl02 per ton of pulp. The amounts of PCDF and PCDD dropped strongly in
bleaching at the low chlorine ratio. The concentration of PCDFs and
PCDDs in general was only slightly above the detection limits in the
pulp as well as in the total effluent. These results confirm those of
the laboratory study (Part 1) which suggested that the chlorine ratio
used in the first bleaching stage is important in the formation of
PCDFs and PCDDs.
Combinations of treatment of effluents in an aerated lagoon, the use
of oxygen bleaching, partial replacement of chlorine by chlorine
dioxide and/or applying low chlorine ratio bleaching in combination
with reinforced alkaline extraction may yield effluents which meet
advanced requirements regarding protection of fish and other organisms
living in pulp mill receiving water against toxic effects; and
according to all present knowledge, reduce chances of any widely
spread detrimental environmental effects of chlorinated organic
materials.
Paper discusses modified cooking, oxygen delignification and PRENOX.
Information is presented related to Kappa numbers, AOX, TOCl and
costs.
Researchers at PAPRICAN screened various microorganisms and found that
Coriolus versicolor can bleach hardwood kraft pulp by up to 15
percentage points with a drop in Kappa number from 11.6 to 7.9. The
bleaching effect of C. versicolor appears to be limited to hardwoods
since experiments with spruce pulp failed to increase brightness.
22
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
BLEACHING
TITLE
AUTHOR
REFERENCE
SYNOPSIS
4.69 Operational
experiences from a
new chlorination
control system based
on on-line
measurements of
Kappa number
4.70 Advances in bleach
plant design lower
capital and
operating costs
4.71 Bleaching of kraft
pulp without
formation of dioxins
4.72 Alternate process
for bleaching could
help in reducing
TOCls, dioxin
4.73 Honox-L for
decreasing AOX
and/or dioxin
4.74 Non-chlorine
bleaching of HCC-
pulp
4.75 Monox-L information
and data
4.76 Mill trials of
substantial
substitution of
chlorine dioxide for
chlorine: part II
Soderberg, J.,
Almberg, M.,
Kubulnteks, E.,
Lundqvist, S.O.,
and Lowenberg,
C.
Tait, D.H.
Vaheri, M., et
al.
Galluch, R.J.
Hurst, N.M.
TAPPI Journal,
November 1988, pp.
145-149
Diliner, B.,
larsson, L.O.,
and Tibbling, P.
Quantum
Technologies,
Inc.
Pyrke, D.C.
Pulp & Paper,
January 1986, pp.
70-72
Dioxin '89,
September 1989
Pulp & Paper,
September 1989, pp.
145-147
CPPA Proceedings,
76th Annual Meeting
Technical Section,
Montreal, Quebec,
February 1-2, 1990,
pp. B313-B314
TAPPI Proceedings,
1989 Pulping
Conference, Seattle,
Washington
Pulp & Paper Canada,
90:6, 1989, pp. 93-
97
In a new control system for chlorination, the change of active
chlorine is based on on-line measurement of the Kappa number of the
pulp entering the bleach plant. The control system also accounts for
variations in production, temperature, etc. The Kappa number after
the alkali extraction stage is also measured on-line. The control
system is installed in a bleach plant for softwood kraft pulp, where
the residual chlorine has decreased, and the working conditions have
improved. The control system is flexible during operation under
various bleaching conditions.
Improved washing and mixing technologies reduce chemical consumption
without offsetting power usage and effluent increases.
Monox-L technology, successful in five plant trials, maintains pulp
quality similar to that produced with chlorine dioxide.
Monox-L is a cost effective bleaching agent which can significantly
reduce the levels of both AOX and dioxins produced as compared to
conventional bleaching sequences.
The paper discusses how a combination of modified continuous cooking
(MCC) and oxygen delignification gives a pulp of sufficiently low
Kappa number (13) for final bleaching without the use of elementary
chlorine. HCC oxygen pulp has been bleached 0(EO)OD and D(EOP)DD to
90X + ISO brightness with retained strength characteristics. The
effluent load from the D(EOP)DD sequence is expected to be very low,
the measured AOX being only 0.9-1.0 kg/ADMT.
Information end data related to the use of Honox-L as a bleaching
chemical, including BOO, COD, color, TOCl, AOX, chloroform and dioxin
effluent data, capital and O&H costs and energy requirements.
Recent trials in market softwood kraft pulp milts situated on the B.C.
coast and in the southern U.S. have shown that increasing chlorine
dioxide substitution from 10 to 30 percent in the chlorination stage
decreases bleaching chemical consumption and bleaching cost while
maintaining pulp quality. Bleaching chemical savings of C$1.50 to
2.50 per ton were achieved.
23
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
BLEACHING
NUMBER
AUTHOR
REFERENCE
SYNOPSIS
4.77 Modifying the
bleaching process to
decrease AOX
formation
4.78 Mill trials of
substantial
substitution of
chlorine dioxide for
chlorine
4.79 Mill trials of
substantial
substitution of
chlorine dioxide for
chlorine - part III:
medium consistency
4.80 N02 treatment of
kraft pulp followed
by oxygen
bleaching -
influence of black
liquor
4.81 Technologies for
reducing dioxin in
the manufacture of
bleached wood pulp -
background paper
4.82 Hydrogen peroxide in
alkaline extraction
improves pulp
quality
4.83 Reduced discharge of
TOCl with a hot (EO)
stage
Llebergott, N.,
van Licrop, B.,
Nolin, A.,
Faubert, H., and
Laflamme, J.
Pyrke, O.C.,
Francis, R.C.,
and Reeve, O.U.
Rempel, U.,
Pyrke, D.C., and
Ouchi, M.D.
Samuelson, 0.,
and Ojteg, U.
Office of
Technology
Assessment,
Washington, D.C.
Hook J..
Meuller, L., and
Wai I in, S.
Sjoblom. K., and
Hardmeier, P.
CPPA Proceedings,
76th Annual Meeting
Technical Section,
Montreal, Quebec,
February 1-2, 1990,
pp. B229-B238
TAPPI Proceedings,
1985 Pulping
Conference, pp. 543-
551
Unpublished
TAPPI Journal,
February 1990, pp.
141-146
Library of Congress,
Catalog Card No. 89-
600719
Nordisk Cellulose 2,
No. 2, March 1985,
pp. 47-50
TAPPI Proceedings,
1988 International
PUlp Bleaching
Conference, Orlando,
FL, June 5-9, 1988,
pp. 263-270
This report describes the effects of E0, £„,, and 0 delignification and
of a wide range of chlorine dioxide substitution to 70X, which
produced less chlorinated phenolic compounds in the bleach effluents.
The BOO and COO in the effluent decreased only with very high chlorine
dioxide substitution levels.
Three mill trials have recently been conducted in Canada where C102
substitution was raised to the 30-50% range. Total equivalent
chlorine and caustic consumption decreased significantly in all three
mills resulting in savings of $1.55, $1.94 and S2.36 CDN/ADT. Pulp
quality parameters were unchanged: strength, cleanliness and
brightness. Bleach plant effluent color and B006 were significantly
decreased: Toxicity test results were somewhat erratic but decreased
toxicity was indicated.
A recent trial at a market softwood kraft pulp mill on the west coast
of British Columbia with a medium consistency chlorination stage has
shown that increasing C102 substitution from 5 to 50% decreases
bleaching chemical consumption, bleaching cost, and improves pulp
quality. Discharges of chlorinated organic compounds, including PCDDs
and PCDFs, from the pulp mill to the receiving water have been
decreased by over SOX. PCDDs and PCDFs in bleached pulp have also
been decreased substantially.
Kraft pulp from softwood containing large amounts of black liquor was
delignified by oxygen bleaching following pretreatment with nitrogen
dioxide. The alkaline pulp was treated with N02 for a few minutes at
a high or medium consistency. After ripening for 180 minutes the pulp
was oxygen bleached. A Kappa number of 3.5 was obtained even when the
pulp contained 43 kg of solids from the black liquor per 100 kg pulp.
Discussion of alternative technologies to reduce formation of dioxin
in bleached pulp. Oxygen pretreatment for delignification and
substituting other chemicals for chorine are evaluated.
Several bleach plants are using hydrogen peroxide in the alkaline
extraction stage. Advantages and disadvantages of this practice are
discussed.
Chlorine consumption can be reduced by increased temperature in the EO
stage. For a given pulp and bleaching sequence, a TOCl level can be
achieved for a minimum total consumption of chlorine dioxide in the
hot EO stage. If economics permit, peroxide added to the EO stage at
75 C can substitute for an EO stage at 90 C.
24
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
BLEACHING
NUMBER
TITLE
4.84 Environmentally
friendly (bleaching)
processes of the
future
4.85
4.86
4.87
4.88
4.89
Bleaching plants for
the 90's
Effect of chloHne
dioxide substitution
on bleaching
efficiency and the
formation of
organically-bound
chlorine
Hydrogen peroxide
technology for
chlorine reduction
AUTHOR
Axegard, P.
Idner, K.
Axegard, P.
Methods to minimize
the formation of
lipophilic chloro-
organics in
bleaching
Environmental
aspects of short-
sequence bleaching
Anderson, J.R.,
and Carmichael,
D.L.
Axegard, P.
Suss, J.R., Eul,
W.L.,
Nlnroerfroh, N.,
and Meier, J.
REFERENCE
TAPPI Proceedings,
1989 Bleach Plant
Operations Seminar,
Charleston, SC,
March 5-9, 1989, pp.
195-200
Swedish Pulp & Paper
Journal, No. 1,
1987, pp. 50-52
TAPPI Proceedings,
1986 Pulping
Conference, Toronto,
October 26-30, 1986,
Book 1, pp, 179-186
CPPA Proceedings,
76th Annual Meeting
Technical Section,
Montreal, Quebec,
February 1-2, 1990,
pp. B209-B216
TAPP! Proceedings,
1988 Pulping
Conference, New
Orleans, LA, pp.
307-314
TAPPI Proceedings,
1990 Environmental
Conference, Seattle,
Washington, April 9-
11, 1990, pp. 503-
513
SYNOPSIS
Overview by STFI on ways of reducing TOCl in bleach plant effluents
such as extended delignification, oxygen delignification, chlorine
dioxide substitution and oxygen extraction. Discussion on treatment
of bleach plant effluent using recycling, membrane filtration and
biological processes.
Review of alternatives for reducing TOCl in bleach plant effluents to
meet regulatory requirements, demands for lower production costs, and
improves pulp quality. Operating costs are predicted to be lowered by
increased use of process control equipment and fewer bleaching stages.
Investigation of two alternatives for decreasing the consumption of
chlorine by using more chlorine dioxide in the bleaching sequence.
Advantages of replacing the Cl with C102 at different stages of the
sequence, and ratios of formation of different chlorates with
decreased Cl consumption are discussed.
A technology for chlorine reduction involving the use of hydrogen
peroxide in conventional alkaline extraction stages is described.
Mills that have used peroxide have achieved chlorine reductions of 20-
35X and have shifted operations into a "no detectable dioxin" regime.
This use of hydrogen peroxide is emerging as an alternative technology
for reduction in chlorine consumption. In addition it has been shown
to work in combination with other chlorine reduction technologies to
achieve very significant reductions in AOX level.
Conventional, oxygen dilignified and PRENOX treated softwood kraft
pulps have been bleached in the laboratory. The consumption of C12
and the C102 substitution level were varied over a targe range. AOX
is reduced linearly with a decreased consumption of the elemental
chlorine in molecular C12 and C102. Chlorinated phenolics were found
to be affected strongly by the C12 consumption. Below a C12 multiple
of about 0.05 virtually no highly chlorinated phenolics could be
found.
Low Kappa factor chlorination, recommended to decrease the amount of
halogenated compounds in the effluent, results in insufficient
delignification. The results of studies show that the application of
oxygen delignification is more effective in reducing halogenated
compounds than chlorine dioxide substitution. Very low levels of
halogenated compounds are the result of high-intensity oxygen
delignification followed by chlorine dioxide and hydrogen peroxide
treatment.
25
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
BLEACHING
NUMBER
TITLE
4.90 AOX reduction in
bleach plant
effluent using
enhanced oxidation
4.91 Hydrogen peroxide
addition to Eo
bleaching stages is
beneficial
1.92 Kraft mill bleach
plant effluents:
recent developments
aimed at decreasing
their environmental
impact, part I
4.93 Kraft mill bleach
plant effluents:
recent developments
aimed at decreasing
their environmental
impact, part 2
AUTHOR
Smith, P.U.
Althouse, E.B.
Heimburger,
S.A., Blevins,
D.S., Bostwick,
J.H., and
Donnini, G.P.
Heimburger,
S.A., Blevins,
D.S., Bostwick,
J.H., and
Donnini, G.P.
REFERENCE
TAPPI Proceedings,
1990 Environmental
Conference, Seattle,
Washington, April 9-
11, 1990, pp. 769-
m
Pulp & Paper, June
1988, pp. 68-70
TAPPI Journal,
October 1988, pp.
51-59
TAPPI Journal,
November 1988, pp.
69-78
The use of second generation enhanced oxidation processing (EOP)
designed to reduce chlorinated phenolics (AOX) in bleach plant
effluent was studied. Hill trials were conducted in order to optimize
treatment alternatives under varying production conditions.
Appropriate amount of high intensity ultraviolet light together with
chemical oxidants (ozone and HZ02) were applied to reliably reduce
influent AOX levels from 3.5-4.0 kg/ton to 2.5 and 1.5 kg/ton.
The addition of both peroxide and oxygen in the first extraction stage
will allow improved production at very low capital costs. Benefits
Include a decrease in the E stage Kappa of 10-25% with an increase in
brightness of 5-15 points.
A review of developments in the technology of pulping and bleaching
has demonstrated new ways to decrease the formation of chlorinated
organic materials. A review of the composition of bleach plant
effluents and effluent treatment methods was also studied.
In Part 1, processes that reduce the chemical demand of pulp by
lowering the Kappa number prior to bleaching were investigated. These
methods included extended delignification and oxygen delignification.
In Part 2, other approaches such as chlorine dioxide substitution,
oxygen extraction, hydrogen peroxide reinforcement, ozone and
alternative bleach schemes without chlorine are examined. Treatment
methods including biological and physical/chemical are also
investigated.
26
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
CHEMICAL RECOVERY
NUMBER
TITIE
AUTHOR
REFERENCE
SYNOPSIS
5.0 CHEMICAL RECOVERY
5.1 Burning non-
condenslble gases.
5.2 Characterizing
emissions from a
modern kraft
recovery furnace
5.3 NOx reduction from a
recovery boiler by
injection of an
enhanced urea
solution (NOxOUT
PROCESS)
5.4 Determination of
black liquor
calorific value
5.5 Ultrefiltration
studies on a kraft
black liquor
Burgess, T.
Oscarsson, B.,
Bentley, Keith
H., and Hood,
Sarah U.
Lovblad. R.,
Moberg, G.,
Olausson, L. and
Bostrom, C.
TAPPI Press,
Environmental
Issues: An
Anthology of 1989,
pp. 247-248
TAPPI Proceedings,
1991 Environmental
Conference Book 2,
pp. 1053-1060
TAPPI Proceedings,
1991 Environmental
Conference Book 2,
pp. 1071-1075
Chao, E.E.,
HcDonald, K.L.,
and Garby, A.C..
Hill, Marquita,
and Fricke,
Arthur L.
TAPPI Journal, June
1984, pg. 112
TAPPI Journal, June
1984, pp. 100-103
Non-condensible gases (NCG) containing reduced sulfur gases (TRS) are
now collected and burned in kraft pulp mills as a method of reducing
mill odor. These gases are burned in lime kilns, boilers and
incinerators. None of these is a perfect place to burn NCG, as each
has advantages and disadvantages.
A new kraft recovery boiler was started up at Georgia-Pacific's
Woodland, Maine mill in August 1989. Continuous emissions monitors
were installed for sulfur dioxide (S02), oxides of nitrogen (NO,),
total reduced sulfur (TRS), carbon monoxide (CO), and opacity. This
paper describes the design considerations for meeting very stringent
emissions limits, the interrelationship of the pollutants, and
operating experience in achieving day-to-day compliance.
After a preliminary study of different NOx reduction techniques, Sodra
Skogsagarna commissioned a full scale test of the NOxOUT process in
the existing recovery boiler at Honsteras from Gotaverken Energy in
cooperation with Petrokraft. The project has shown that thermal
reduction of nitrogen oxides using the NOxOUT process can successfully
be applied to recovery boilers. More than 60X reduction was achieved
despite the low NOx level without treatment. No disturbances or other
negative effects on the operation of the recovery boiler was observed
during the test run. No negative effects in the chemical recovery
cycle was observed during the test runs.
In this study, uttrafiltration was used as a means to separate kraft
black liquor components into high and low molecular weight fractions.
Ultrafiltration effectively removed inorganic salts and organic acids
from black liquor as well as a portion of the molecules absorbing in
the ultraviolet. When a membrane with a nominal molecular weight
cutoff of 100 was used, the low molecular weight lignin-like molecules
removed into the ultrafiltrate had a different pattern of light
absorption than the lignin left behind in the cell, and there was a
difference in the sulfur and carbohydrate content of these fractions.
27
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
CHEMICAL RECOVERY
NUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
5.6
5.7
5.8
5.9
5.10
Lignin recovery from
kraft black liquor:
preliminary process
design
Loutfi, Hassan,
and Blackwell,
Brian
TAPPI Journal,
January 1991, pp.
203-210
Kraft lignin: a
potential fuel for
lime kilns
Chemical Recovery
Update -
International
Chemical Recovery
Conference, New
Orleans (Summaries
of conference
papers)
Gasification of
black liquor char
with CO, at elevated
pressures
Richardson, B.,
and Uloth, V.C.
TAPPI Journal,
October 1990, pp.
191-194
TAPPI Journal, Vol.
68, No. 4
Frederick,
William J., and
Hupa, Nikko M.
TAPPI Journal, July
1991, pp. 177-183
Alternative kraft
recovery processes
Empie, Jeff H.
TAPPI Journal, May
1991, pp. 172-276
A process design and a capital cost estimate were prepared for a
lignin recovery process. The process includes CO, precipitation,
lignin separation, acid washing, and product drying. The process
equipment was sized to recover 9.5X of the lignin originally present
in the black liquor for a typical kraft mill producing an annual
average of 700 a.d. tons/day. The economic evaluation Mas based on
the sale of 21X of the recovered tignin as a specialty chemical, with
the remainder used as fuel for the lime kiln. A computerized mass
balance was developed to examine the impact of lignin total installed
capital cost of about $19 million (Canadian) and a pay-back time of
four years.
As the lignin moisture content increased from OX to 50X, the amount of
fossil fuel displaced by a constant dry weight of lignin decreased by
only 6-7X
The kinetics of gasification of black liquor chars with carbon dioxide
were studied under pressurized conditions (1-30 bar) and 600-800°C.
The rate of gasification was found to be slightly less than first
order in C02, and the rate of gasification was strongly inhibited by
CO. As pressure was increased, CO inhibition more than offset the
effect of C02 on the gasification rate. The net impact was that the
rate of gasification at constant C0/C02 ratio decreases by a factor of
4.6-6 as total pressure increases from 1 bar to 30 bar. The rate of
gasification with C02 is temperature sensitive, increasing by more than
a factor of 10 with a 100°C increase in temperature. The reactivity of
different kraft chars is not the same. In experiments with chars from
three liquors, the rate varied by a factor of two at identical
gasification conditions.
28
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
CHEMICAL RECOVERY
NUMBER
TITLE
MITHOR
REFERENCE
SYNOPSIS
5.11
Computer modeling
and design of a
fluidized bed dryer
for kraft black
liquor
Sell, Nancy J.,
and Clay, David
T.
TAPPI Journal, June
1991, pp. 177-179
5.12
Vaporization from
alkali carbonate
melts with reference
to the kraft
recovery furnace
Cameron, J.H.
Journal of Pulp and
Paper Science, July
1988, pp. 76-81
5.13
5.K
Tempella recovery
system for small-
scale pulp mills
Pyrolysis gas
explosions
Rimpi, P. and
Hop!a, R.
Grace, Thomas
Pulp and Paper
Canada, 1987, pp.
Z86-Z89
PIHA Magazine
February 1991, pp.
«9-50
The solids content of concentrated black liquor is a critical
parameter in the design and operation of a kraft recovery boiler. The
trend today is to go to higher solids content to increase the
effective capacity of the boiler and potentially to improve its
performance. A fluidized bed dryer achieved 95X dried solids in
laboratory tests. The fluidized bed dryer was mathematically modeled
using the 1PC MAPPS computer program. HAPPS was originally designed
for calculating mass and energy flows, but its overall structure makes
it ideal also for equipment design. Process design parameters are
summarized for a fluidized bed black liquor dryer supporting an
equivalent increase of 182 a.d. tons of pulp per day.
This paper examines the processes responsible for fume generation in
the draft furnace. Fume generating under oxidizing conditions was
found to be an order of magnitude greater than under strongly reducing
conditions. Addition of sodium hydroxide to the sodium carbonate-
sulphide melt did not increase the fuming rate. Potassium and
chloride levels in kraft furnace fume are lower than values calculated
from equilibrium data; however, if the enhanced vaporization of
sodium due to oxidizing conditions is taken into consideration, the
low potassium and chloride levels in the fume can be explained.
Raoult's law gives an accurate description of sodium chloride
vaporization from a sodium carbonate-sulphide-chloride smelt under
oxidizing conditions.
Tampella has developed a recovery system compromising the liquor
burning in a package recovery boiler and the chemical conversion for
sodium-based cooking processes. It is aimed at small scale pulp mills
and for mills where the recovery boiler is a bottle neck.
Pyrolysis gases are combustible gases that are produced when black
liquor is dried and heated. Pyrolysis of one gallon of 65X solids
black liquor could produce as much as 50 cubic feet of combustible
gas. Pyrolysis gas formation is an inherent part of black liquor
burning and normally causes no problems. Formation and burning of
pyrolysis gases is responsible for most of the heat released as black
liquor burns. The gases burn as soon as they are released, forming
the fireball that can be seen in the furnace.
29
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
CHEMICAL RECOVERY
NUMBER TITLE
5.15 Agitation helps mill
raise storage
capacity and recover
chemicals
5.16 Black liquor solids
content
5.17 Biomass gasification
project gets funding
to solve black
liquor safety and
landfill problems
5.18 High-solids black
liquor combustion -
Tanipella's Super
Combustion system
5.19 Black liquor
combustion research
5.20 Kraft Black Liquor
Cooperative Program
reports progress
5.21 Destination of
black liquor: pilot
plant tests
5.22 Evaporator vapor
sampling
5.23 Entrained black
liquor solids and
viscosity
selectivity in
oxygen
delignification
reinforced with
hydrogen peroxide
AUTHOR
Ramos, J.
REFERENCE
Pulp and Paper,
August 1988, p. 14
Grace, Thomas
Black, Norman P.
Hyoty, P.A., and
Ojala, S.T.
Harrison, Ray E.
Kopfmann, K.,
and Hudeczek, W.
Pelkey, Edward
R., Nd Schluter,
Jill L.
Parthasarathy,
V.R.
PIHA Magazine
TAPPI Journal,
February 1991, pp.
65-68
TAPPI Journal,
January 1988, pp.
108-111
TAPPI Journal, Vol.
67, No. 7
TAPPI Journal,
November 1987, pp.
145-147
TAPPI Journal,
October 1988, pp.
139-147
TAPPI Journal,
December 1988, pp.
227-228
TAPPI Journal,
September 1990, pp.
243-247
SYNOPSIS
Simpson Paper Co. manufactures nearly 270,000 metric tons per year of
pulp and 290,000 metric tpy of paper at its Pasadena, Texas mill. As
part of its liquor storage system, the mill uses a 48 ft deep, 114 ft
diameter API (American Petroleum Institute) tank to store black liquor
derived from its pulping process. The liquor is then routed to
recovery boilers where chemicals used in the treatment of woodchips
are extracted.
System forms no smelt and makes clean fuel gas that can be burned in
inexpensive, gas-ffred power boilers, calciners, or gas turbines.
A system of firing black liquor at SOX dry-solids content is in
commercial operation and has total operator acceptance.
The tests have enabled the design and construction of a large
industrial plant for processing rice straw and bagasse using the soda
process.
Results are reported from a study on the effects of entrained black
liquor solids on the rate of delignification and on the viscosities of
loblolly pine kraft pulps delignified with oxygen and oxygen
reinforced with hydrogen peroxide (PO). The amounts of entrained
solids ranged from 0 to 85 kg/o.d. metric ton of pulp is beneficial,
increasing the rates of oxygen delignification and PO delignification.
However, black liquor solids entrained with the pulp affected the pulp
viscosity. The overall selectivities (Kappa number vs. viscosity) of
oxygen and PO-bleached pulps were slightly lower for pulps with
entrained solids. Using hydrogen peroxide (0.5X on pulp) to reinforce
the oxygen stage has yielded pulps lower in Kappa number and equal in
viscosity to oxygen-delignified pulps.
30
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
CHEMICAL RECOVERY
NUMBER
TITLE
AUTHOR
REFERENCE
5.24 The Influence of
chlorides on the
fireside behavior in
the recovery boiler
Hupa. H.,
Backman, R.,
Skrifvars, B-J.,
and Hyoty, P.
TAPPI Journal, June
1990, pp. 153-158
Increasing the chloride content in the black liquor has various
effects on the fireside behavior of the recovery boiler. Chlorides
tend to become enriched in the gas phase, depending mainly on bed
temperature. The most important chlorine-containing compounds in the
gas phase are NaCl(g), KCKg), and HCl(g). HCl(g) may cause rapid
corrosion on steel surfaces by forming volatile FeCl2(g). Chlorides
strongly affect the behavior of the dust in the flue gas channel. The
essential parameters governing the superheater fouling and corrosion
are the sticky temperature TI6 and the flow temperature !„,. These
temperatures are influenced by the chlorides. Also, the sintering
rate of solid dust deposits in the boiler bank and economizer is
increased when the chloride content of the dust increases.
5.25 Preparation of kraft
lignin from black
liquor
5.26 Feasibility study;
black liquor
gasification and use
of the products in
combined-cycle
cogeneration
5.27 Black liquor
gasification and use
of the product gases
in combined-cycle
cogeneration - Phase
II
5.28 International
Chemical Recovery
Conference, New
Orleans
Kim, Hongkyu,
Hill, Marquita
K., and Fricke,
Arthur L.
Kelleher, E.G.
TAPPI Journal,
December 1987, pp.
112-116
TAPPI Journal, April
1984, pp. 114-117
Kelleher, E.G.
TAPPI Journal,
November 1985, pp.
106 - 110
Summaries for
Conference
Papers
TAPPI Journal, Vol.
68. No. 4, pp. 31-35
The purity of lignin precipitated at low pH from kraft black liquor
was examined along with the factors that improve purity. The recovery
of lignin by precipitation was also evaluated in an attempt to
optimize recovery at high purity. The lignin preparation methods used
were compared for their precision by using ion chromatographic, UV-
visible spectrophotometric, and inductively coupled plasma
spectrometric (1CP) analytical methods.
A study of kraft black liquor gasification was sponsored by the U.S.
Department of Energy. The results of a small-scale experimental
evaluation by Rockwell International, using its Molten Salt
Gasification Process, are used in computer simulations of a complete
steam and electric power supply system. This power system is a
combined-cycle system based on a coal and bark fired combination
boiler and a gas turbine. Capital and operating costs were compared.
Based on this limited feasibility study, the system appears to have
potential in energy efficiency, economics, and safety.
Bench-scale and pilot-scale tests of kraft black liquor gasification
have been completed in a study cosponsored by the U.S. Department of
Energy. These tests of gasification with air confirm the feasibility
of obtaining product gases uith a higher heating value sufficient for
firing in a standard gas-compressor-turbine-expander set. The overall
process has the potential for higher efficiency, lower costs,
modularity, and elimination of the explosion potential associated with
the Tomlinson furnace.
31
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
RECAUSTISIZING
NUMBER
AUTHOR
REFERENCE
6.0 RECAUSTICIZING
6.1
6.2
6.3
6.4
6.5
6.6
Combustion of Ugnin
In a pilot lime kiln
Substitution of oil
by hogged fuel in a
kraft process lime
sludge kiln
Richardson, B.,
Uatkinson. A.P.,
and Barr, P.V.
Roue, Ian G.
TAPPI Journal,
December, 1990, pp.
133-137
TAPPI Journal,
February 1984, pp.
86-90
Closing up the kraft
mill chemical
balance:
alternative caustic
sources
Lindberg, H.,
Edwards, L. and
Saltln, G.
TAPPI Proceedings,
1991 Environmental
Conference Book 1,
pp. 53-58
Neu opportunities
for TRS reduction
stack emissions
in
Evaluation of
oxidized white
liquor as an alkali
source
Kraft lignin: a
potential fuel for
lime kilns
Stuplich and
Swedock
Alaya, Hagnotta,
Zterdt, Zanchin
and O'Ceerny
Richardson and
Uloth
TAPPI Press,
Environmental
Issues: An
Anthology of 1989,
pp. 253-254
TAPPI Notes, Oxygen
Delignification
Symposium, 1990, pp.
153-161
TAPPI Proceedings,
Pulping Conference
Book 1, 1990, pp.
451-455
Dried lignin powder can be satisfactorily burned in a pilot lime kiln
either on its own or in conjunction with natural gas.
Hogged fuel, typically at 55X moisture content, was combusted in a
wet-cell burner and the flue gases applied to a lime sludge kiln. Up
to 78X oil substitution was achieved, consistent with satisfactory
lime quality and availability. Specific energy consumption was high
because heat transfer was less efficient. Computer simulation
techniques were used to develop parameter profiles throughout the kiln
and to predict optimal performance. Optimized kiln conversion was
shown to be economically advantageous if hogged fuel is available for
$7.00/m3 or less, assuming an oil price of $30/bbl ($0.189/L).
With the current costs for sodium hydroxide and sodium carbonate and
if kiln capacity is available, it may be economical for some mills to
change from sodium hydroxide to sodium carbonate for kraft mill make
up. Electrodialysis of R8 spent salt is undergoing pilot plant
testing in Finland. It converts R8 spent salt to sodium hydroxide and
sulfuric acid. Recycling first extraction stage (E1) filtrate to
chemical recovery eliminates about 35X of the total sodium makeup
required in a kraft mill. At present. El filtrate recycle can only be
considered on an environmental basis.
The paper is a progress report on the new direction we've seen in TRS
control and reduction. During work with lime mud conditioners, we've
found what we consider to be a new control mechanism for the reduction
of TRS emissions.
The technical and economic aspects of using oxidized white liquor in
oxygen delignification stages are reviewed. Oxidized white liquor is
compared to other alkali sources through a review of the existing
literature, new laboratory work, and mill experience. An economic
comparison is made between the OXPRO system, which oxidizes white
liquor with oxygen, and an air oxidation system. Other end uses for
oxidized white liquor, such as extraction stages and scrubbers, are
reviewed.
A computer program was developed to facilitate mass and energy
balances about a lime kiln and to assess the potential effects of
fossil fuel replacement with lignin.
32
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
RECAUSTISIZING
NUMBER
TITLE
AUTHOR
REfERENCE
SYNOPSIS
6.7 Lime kiln emission Kiiskila, E.
control
6.8 Quick kiln retrofits Ryan, M.
for TRS improvement
6.9 Lime kiln energy Perry, R.E.
conservation - Nave
we forgotten the
I.D. fan?
6.10 Evaluating the Hsieh, C.L.
energy performance
of a lime kiln
TAPPI Press.
Environmental
Issues: Anthology
of Published Papers,
1990, pp. 410-415
TAPPI Press,
Environmental
Issues: Anthology
of Published Papers,
1990, pp. 459-461
TAPPI Journal, June
1989, pp. 243-246
TAPPI Journal, Vol.
66, No. 9
The formation of TRS, dust, SOx and NOx as well as their theoretical
formation mechanism are discussed. The measured emission levels and
the ways to influence their formation are presented based on
industrial experiences. The ability of flue gas cleaning systems to
handle these compounds is discussed.
A laboratory scale kiln was studied to determine the best position in
a production unit rotary lime kiln to piece a Turbushield gas mixer
for reduction of TRS emissions.
A procedure for evaluating the energy performance of a lime kiln has
been developed. It is based on chemical species balances, thereby
avoiding the usual difficulties and errors in trying to measure lime
mud and product lime flows. Together with other readily obtainable
kiln data, complete material and energy balances can be calculated,
giving both the total energy requirement for producing a ton of lime
and the distribution of this energy. This latter information can
indicate where possible energy savings can and should be made. The
procedure was tested in a kraft mill with satisfactory results.
33
POLLUTIOM PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
POWER GENERATION
NUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
7.0 POUER GENERATION
7.1
7.2
7.3
7.4
Emissions from a
wood-boiler equipped
with a direct
contact fuel dryer
Campbell, Ken
C., and Caron,
Andre L.
Agricultural use of
wood ash as a
fertilizer/liming
material
Achieving hog fuel
handling system
cleanliness with an
integrated dust
control program
Hogged fuel boiler
ash physical and
chemical
characteristics and
their influence on
design and operation
of a woodwaste
landfill
TAPPI Proceedings,
April 1987
Environmental
Conference, pp. 143-
145
Naylor, Lewis
H., and Schmidt,
Eric J.
Cobb, W., and
Termine, f.
TAPPI Proceedings,
April 1986
Environmental
Conference, pp. 157-
165
TAPPI Proceedings,
April 1987
Environmental
Conference, pp. 137-
141
Edens, Mark H.,
and Hannah, Mark
A.
TAPPI Proceedings,
1991 Environmental
Conference Book 2,
pp. 849-863
The Boise Cascade mill at Vest Tacoma, Washington has recently
installed a fluidized bed fuel dryer to compliment its hog fuel fired
boiler. The objective was to reduce the moisture content of the fuel
fired, improve combustion and heat recovery efficiency of the unit,
thus substantially reducing the firing rate of auxiliary fuel. The
dryer was successful in accomplishing the above. Due to improved
efficiency of the boiler, some changes in the emission of particulate,
nitrogen oxides, carbon monoxide and total gaseous non-methane
organics would be expected. Summarized will be the results of surveys
conducted to better understand the above.
Paper mill wood-derived boiler ash was mixed with two acid soils at
rates equivalent to 0, 2.24, 4.5, 9.0, 17.9, and 35.9 metric ton/ha in
a soil incubation study to evaluate changes in extractable nutrients
and soil pH. Levels of extractable P, K and Ca were increased
linearly with application rate. Soil pH was increased linearly with
the logarithm of the application rate. The ash was compared with
commercial potash fertilizer and agricultural limestone. The
equivalent neutralizing value was about half of that for agricultural
limestone.
Excessive dust generated from the hog fuel handling system at Smurfit
Newsprint's Newberg, OR mill was costing the company $270,000 a year
in lost fuel and increased waste treatment costs. In addition to
being a general nuisance, the dust created a hazardous working
environment, increased cleaning costs, and reduced equipment
reliability and lifetime. After a complete system survey was
conducted, mechanical, chemical, and operations changes were made to
reduce carryback of the hog fuel and the amount of fugitive dust. The
shrouds and the implementation of a foam dust control program vastly
improved the cleanliness of the hog fuel handling system.
Daishowa America Company operates a telephone directory paper mill in
Port Angeles, Washington, that produces approximately 75 cubic meters
per day of hogged fuel boiler ash. The mill was purchased by Daishowa
in early 1988. The ash had been disposed of by the previous owners of
the mill at a privately owned landfill since 1982. Daishowa purchased
this landfill in late 1988 and upgraded the site to meet regulatory
requirements. Analysis of physical and chemical characteristics of
the hogged fuel boiler ash suggested the ash has a low moisture
holding capacity and would produce a leachate that could impact
groundwater quality. Ash characteristics guided preparation of a site
development and operations plan that includes recommendations for
interim temporary cover for leachate control, since implementation of
the plan in 1989, groundwater monitoring results demonstrate that site
operation end development is not causing significant impacts to
groundwater quality near the site.
34
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
POWER GENERATION
NUMBER
TITLE
AUTHOR
REFERENCE
7.5
7.6
7.7
7.8
Fast-track
development of a
lined Moodwaste/ash
landfill in
Washington state
Springer, Elaine
T., and Jones,
Brian D.
Bubbling bed units
for waste fuel
consumption in the
pulp and paper
industry
Environmentally
sound power
generation
Applications of
Federal Republic of
Germany flue gas
cleaning technology
to U.S. pulp and
paper industry
Gangs, R. C.
Accortt and
Collins
Keen and
Helmenstein
TAPPI Proceedings.
1991 Environmental
Conference Book 2,
pp. 865-877
TAPPI Proceedings,
1991 Environmental
Conference Book 1,
pp. 405-411
TAPPI Press,
Environmental
Issues: An
Anthology of 1989,
pp. 233-239
TAPPI Press,
Environmental
Issues: Anthology
of Published Papers,
1990, pp. 397-409
This paper describes how a conceptual plan was prepared for the
Shotwell Landfill and how Phase 1 was developed and in operation
within 15 months of project inception. The new facilities included a
temporary synthetic cover over an existing 2.5 ha sludge landfill; a
new 2.25 ha composite-lined landfill cell; leachate, stormwater, and
groundwater collection and disposal; a lined leachate lagoon and truck
load facility; groundwater monitoring wells; and an operations end
closure plan. This paper describes unusual technologies utilized at
the site, constraints, and permitting challenges associated with the
fast-track schedule.
Many combustion waste fuels lend themselves to bubbling bed fluid bed
combustion applications. The goals of this paper will be to generally
introduce some of the companies that provide small fluid bed
technologies, to describe the technical approach each company takes
and to present relevant experience where possible including a
discussion of projects completed and fuel consumed. Although most of
the major boiler vendors also offer small units for waste consumption
the focus here will be on less well known or smaller vendors.
The design, start-up, and operation of a 300,000 Ib/hr boiler followed
by a spray dry scrubber and electrostatic precipitator for air quality
control are described.
This paper will present historical costs of flue gas cleaning
technology for NOx and SOx as a function of boiler type including
pulverized coal, fluidized bed and stoker firing. A comparison of FRG
emission standards with pending US standards will be included.
35
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
WASTEWATER TREATMENT
NUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
8.0 UASTEUATER TREATMENT
8.1
8.2
8.3
8.4
Treatment of
effluents from the
pulp and paper
Industry by chemical
coagulation
Bench scale study of
dioxins and furan
(2378-TCOD and 2378-
TCDF) treatability
in pulp and paper
uasteuaters
in pul
mill u
Screening study of
the treatability of
dioxins and furans
in bleach plant
filtrates and mill
wastewaters
Some aspects on
biological treatment
of bleached pulp
effluents
Almemark, H.,
Eriksson, 6, and
Hagerstedt, I.E.
Amendola, G.A,
Bodien, O.G.,
and Handy, R.E.
Jr.
Barton, D.A.,
NcKeown, J.J.,
and Brunck, R.A.
Boman, B.,
Frostell, B.,
Ek, N., and
Erikson, K.E.
TAPPI Seminar
Proceedings,
Bleaching and the
Environment,
Seattle, Washington,
September 1988, pp.
251-272
TAPPI Journal,
December 1989, pp.
189-194
NCASt 1989 West
Coast Regional
Meeting, October 4,
1989
Nordic Pulp and
Paper Research
Journal, 1-1988, pp.
13-18
This paper deals with chemical coagulation of bleach plant effluents
uith alum followed by incineration of the sludge and acid recovery of
the coagulants. Costs are projected for full scale operation.
The principal objectives of this study were to determine the solid and
liquid phase distribution of 2378-TCDD and 2378-TCDF in untreated,
partially treated and treated process wastewaters from pulp and paper
mills; and to determine whether chemically assisted clarification
(CAC) might be a feasible alternative for removing those compounds
from internal mill and total mill process wastewater. Results of
bench scale studies indicate that from 30X to 40X of the 2378-TCDD and
2378-TCDF is present in the solid phases of internal mill samples;
greater than 90X in aeration basin effluents; and from 40X to 75 X in
final effluents. CAC proved to be effective at removing 2378-TCDD and
2378-TCDF from internal mill wastewaters, however, less cost effective
than providing improved treatment in existing secondary treatment
facilities.
Unpublished report consists of tables used for presentation at NCASI
1989 West Coast Regional Meeting.
The article describes the most important methods presently used for
external treatment of bleach plant effluents. They are in most cases
designed to reduce BOO and are not very effective in reducing AOX.
None of the biological methods currently used can degrade high
molecular mass material. The possibility of using special fungi, able
to attack the high molecular mass chlorinated lignins, is discussed.
Anaerobic dechtorination is also mentioned. A combination of
physical/chemical methods and biological treatment is proposed for the
development of new purification processes. A combined process with
ultrafiltration end effective biological treatment is estimated to
give at least 95X reduction of BOD and 70-90X reduction of COD and
AOX.
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
WASTEWATER TREATMENT
MUHBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
8.5
8.6
8.7
8.8
8.9
Organic halide in
kraft mill
wastewaterst
factors affecting
tn-mUl formation
and removal by
biological treatment
Design, startup, and
operating experience
for an expanded ASB
treatment system at
Champion's Pensacola
Mill
Pilot plant trials
for LRP, a new
process for
precipitating
organic material
Bryant, C.U. and
Amy, G.L.
Ultrafiltration of
bleach plant
effluent
Hilleke, J.,
Koelsch, S.t and
Arceneaux, 0.
Hynninen, P.
TAPPI Proceedings,
1988 Environmental
Conference, pp. 435-
438
TAPPI Journal,
September 1989, pp.
111-117
TAPPI Journal,
February 1989, pp.
167-170
Jonsson, A.S.
Nordic Pulp and
Paper Research
Journal, t-1967, 23-
29
Dechlorfnation of
high-molecular-
ueight chlorolignin
by the white-rot
fungus Pj.
Chvrsosporium
Pettfnen, J.,
Joyce, T.U., end
Chang, H.M.
TAPPI Journal,
September 1988, pp.
191-194
Chlorine is used as a pulp bleaching agent, resulting in the formation
of various organochlorine compounds that range from simple
chlorophenols to higher molecular weight chlorolignin compounds. In
addition to persisting in the environment, some of these compounds
exhibit toxicity or mutagenicity. Recent work has focused on the use
of the total organic halide (TOX) parameter for measuring the totality
of these compounds.
In December 1986, Champion completed the conversion of its Pensacola
kraft mill to 100% bleached pulp and paper operation. New pine and
hardwood bleach lines were set up, along with an oxygen
delignification sequence. To successfully operate the converted mill
in compliance with new permit conditions, the project included major
modifications to the waste treatment system.
The lignin removal process (LRP) is a new method for precipitating
dissolved or colloidal organic material of high molecular mass from
fibrous waste sludge. Effluents successfully treated have been taken
from bleaching plants, barking rooms and fiber-board mills from white
water systems of some paper and fiber-board mills and from CTMP mills.
Pilot plant trials at a kraft pulp mill and at a fiberboard mill
produced results similar to those obtained by chemical precipitation
and by the previous laboratory tests. The pilot plant results support
ideas for the design of LRP effluent treatment plants. LRP is simple
and inexpensive to incorporate into existing mechanical and biological
treatment and the method is ready for industrial use.
An up-to-date evaluation of capacity and retention of new membranes
with regard to bleach plant effluents has been made. The results from
a trial of seven reverse osmosis, Ultrafiltration and microfiltration
membranes are reported. The trial has even included membranes not yet
commercially available. The trial has demonstrated that some of the
tested membranes could probably combine a satisfactory flux and an
acceptable retention. A rough estimate of the costs shows that
treatment of the E-stage effluent with Ultrafiltration could be
performed within a total cost of approximately 25 SEK per ton of pulp,
Dechlor Ination of chlorolignin in pulp bleaching wastewater was
studied using the white-rot fungus P. chrysosporium immobilized on a
rotating biological contactor. The total organic chlorine content of
chlorolignin decreased almost by 50% during one day of treatment. The
corresponding amount of inorganic chloride was liberated into the
solution. Correlation studies suggested that dechlorination,
decolorization, and degradation of chlorolignin (as COD decrease) are
metabolically connected, although these processes have different
rates. Size exclusion chromatography showed that polymerization took
place in the early stage of the treatment. Low-molecular weight
degradation products were not observed.
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
WASTEWATER TREATMENT
HUMBEB
TITLE
AUTHOR
REFERENCE
SYNOPSIS
8.10
8.11
8.12
8.13
8.H
8.15
Membrane filtration
as a technique for
effluent control in
pulp and paper-making
New flocculation
process portends
progress in color,
dioxin removal
Development and
implementation of a
wastewater control
strategy for APH
Maryvale
Anaerobi c/aerobi c
treatment of kraft
pulping wastes
A review of sludge
landfill ing practice
at selected sites in
the U.S. pulp and
paper industry
Thorsell, L. and
Orchard, T.
Anaerobic
treatability testing
of Canadian pulp and
paper mill
uastewaters
Mass, R.P. and
Neal, J.P.
Qiu, Rongchu,
Benjamin,
M.M.,and
Ferguson, J.F.
Miner, Reid A.
Hall, E.R., and
Cornacchio, L.A.
TAPP1 Seminar
Proceedings,
Bleaching and the
Environment,
Seattle, Washington,
September 1988, pp.
227-243
Pulp & Paper,
September 1989, pp.
154-158
TAPPI Proceedings,
April 1987
Environmental
Conference, pp. 1-5
TAPPI Proceedings,
April 1987
Environmental
Conference, pp. 165-
172
TAPPI Proceedings,
April 1987
Environmental
Conference, pp. 187-
191
TAPPI Proceedings,
April 1987
Environmental
Conference, pp. 235-
239
Paper presents information related to membrane filtration
(ultrafiltration and reverse osmosis). Applications, installations
and costs are presented.
Article discusses how Hansel process removed 90 to 95 percent of
lignin, tannins, and dioxin from secondary treated bleached kraft mill
wastewater.
A study of combined anaerobic pretreatment and aerobic post treatment
was conducted with kraft evaporator condensate and caustic extraction
stage bleaching effluent. In addition, the transformations and
removal of sulfur compounds from the KEC and changes in molecular size
fraction of organic carbon and organic chlorine were measured.
Results indicate that the combined waste is amenable to anaerobic
treatment with removal of a large fraction of the BOD.
In 1986 NCASI collected and detailed design information from 21
landfills receiving pulp and paper mill sludge, and designed since
1977. Discussions at a 1986 NCASI Special Technical Session on Pulp
and Paper Special Technical Session on Pulp and Paper Mill Sludge
Landfill Design and Operation provided additional information. This
paper contains the results of NCASI's information gathering effort.
Included are discussions of the design of liners, bottom and internal
drainage blankets, leachate collection pipes, and landfill cover
materials. Several important operational considerations are also
reviewed.
The anaerobic treatability of wastewaters from several pulp and paper
mills was assessed using chemical and batch biological testing
procedures. The results allowed the identification of candidate
wastewater with the highest priority for further process development
studies, and indicated the potential for applying anaerobic treatment
technology in the Canadian pulp and paper industry.
38
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
WASTEWATER TREATMENT
NUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
8.16
8.17
8.18
8.19
8.20
Utilization of ASB
solids for
reclamation of final
landfill cover and
amendment of forest
soils
An evaluation of
wasteuater treatment
plant capacity and
expansion
requlrements
Primary and
secondary sludge
disposal by spray
irrigation
Wilson, S.A.,
Rahe, Terry, and
Sorenson, Thor
Herman, D.N.,
and Hcgg, D.E.
Eck, Thomas H.
Composting of a
combined RHP/CMP
pulp and paper
sludge
Campbell. A.
Engebretson, R.
and Trlpepl, B.
The efficacy of
enhanced photo-
oxidation for the
reduction of TOCl,
color, and toxicity
in mill aqueous
effluents
Higashi, Cherr
and Crosby
TAPPI Proceedings,
April 1987
Environmental
Conference, pp. 283-
287
TAPP! Proceedings,
April 1986
Environmental
Conference, pp. 241-
2«7
TAPPI Proceedings,
April 1986
Environmental
Conference, pp. 107-
116
TAPPI Proceedings,
1991 Environmental
Conference Book 2,
pp. 727-737
TAPPI Proceedings,
1991 Environmental
Conference Book 1,
pp. 73-83
Approximately 6,000 dry tons of ASB solids were dredged and applied
over a two year period. Project objectives included beneficial use of
solids as a soil amendment on forest land and reclamation of landfill
cover in addition to bringing ASB effluent back into compliance.
Beneficial effects were noted in the productivity of vegetative cover
and in the fertility status of site soils. Metals concentration in
site soils increased significantly due to solids application but did
not exceed regulatory thresholds.
In order to accommodate production expansions, a study was completed
to evaluate wastewater treatment plant capacity end determine upgrade
requirements. The methods used include full scale evaluations, pilot
plant studies and computer modeling. Expansions which will be made to
the wastewater treatment plant include additional aeration, expanded
dewatering capacity (including another dewatering press and increased
polymer storage and delivery systems) more nutrient feed capacity, a
new mix tank/splitter box prior to the primary clarifiers and
modifications to the aeration basin influent feed system.
Southeast Paper Manufacturing Company in Dublin, Georgia produces 85-
90 TPO of primary/secondary sludge from deinked newsprint pulp.
Initial disposal at mill startup in 1979 was in a lagoon.
Investigation of alternative disposal methods included dewatering,
anaerobic digestion, and various land application techniques. The
sludge was difficult and expensive to dewater and anaerobic digestion
appeared impractical. Land application experiments indicated spray
irrigation of the sludge was an acceptable disposal method and had
reasonable costs. A permit was obtained from Georgia EPD. Operating
conditions and experiences are reviewed. The investigation,
permitting, and monitoring requirements are also presented.
A composite, primary and secondary sludge (3:1) from a RHP/CMP pulp
and paper mill producing newsprint was composted using a static pile,
forced aeration process in two 1,700-L insulated reactors. One
reactor controlled temperature at < or = 60°C and moisture content at
60X, whereas the other reactor controlled only temperature at < or =
60°C. The raw sludge was non-hazardous and could be easily composted
without a bulking agent or urea amendnent. In summary, a primary-
secondary mechanical pulp and paper mill sludge was rapidly composted
into a material suitable for safe, beneficial use in agricultural and
horticultural applications.
We have been investigating heterogeneous photooxidation of BKME using
UV light and Ti02 photocatalyst coupled with standard and nonstandard
analyses for TOCl, color, and aquatic toxicity of treated effluent.
Therefore, using the best present conditions, dark brown effluent can
be converted by heterogeneous photooxidation to a clear, colorless,
and odorless solution lacking chloroform and low in aquatic toxicity,
resin acids, and HHH in less than 30 minutes.
39
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
WASTEWATER TREATMENT
TITLE
AUTHOR
REFERENCE
SYNOPSIS
8.21
8.22
8.23
8.24
Treatment
technologies for
orgenochlorine-
contafntng sludges
and concentrates
from external
treatment of pulp
and paper
wastewaters
Recent developments
in the anaerobic
treatment of pulp
and paper industry
wasteuaters
Papermill sludge as
a valuable fuel
Optimization of
biological treatment
systems for enhanced
removal of AOX and
chlorophenolic
compounds
Finnveden, G.,
and Frostell, B.
TAPPI Proceedings,
1991 Environmental
Conference Book 1,
pp.103-113.
Rintela, J.A.,
Sierra-Alvarez,
R., Field. J.A.,
van tier, J.B.,
and Lettinga, G.
TAPPI Proceedings,
1991 Environmental
Conference Book 2,
pp. 777-785
Linderoth, C. E.
TAPPI Proceedings,
1991 Environmental
Conference Book 1,
pp.393-395
Randle, W.,
Hall, E., and
McKinlay, A.
TAPPI Proceedings,
1991 Environmental
Conference Book 1,
pp. 433-443
Literature data and results from current Swedish research have been
used to compile characteristics of and disposal methods for sludges
and concentrates from external treatment of wastewaters from the pulp
and paper industry.
An aerobic treatment has been shown to be an effective, cost-saving
method for reducing the organic pollution load of various types of
forest industry waste streams including condensates, recycling paper
wastewaters and (thermo-)mechanical pulping effluents. However,
anaerobic treatment of more complex forest industry wastewaters (e.g.,
effluents from processes involving chemical treatments and debarking
wastewaters) is often troublesome due to the presence of toxic and
recalcitrant organics, high concentrations of sulfur, and in some
cases high wastewater temperatures. Several measures which can be
applied to render these wastewaters more amenable to anaerobic
treatment are discussed.
Disposal of primary clarifier and secondary biological sludge is a
major problem in many mills in the pulp and paper industry. By
properly dewatering the sludge, it can be made into a valuable fuel
instead of being just a waste product, thus partially replacing other
fuels for steam production in the mill. Thermal drying by utilizing
the heat available in boiler flue gases can be a suitable alternative
to, or compliment to mechanical dewatering. Two principally different
systems are presented. One system utilizes flue gases off an existing
bark fired boiler to redry the sludge prior to combustion in the
boiler. The other system utilizes a portion of the dried sludge in a
suspension burner to provide the necessary drying heat. Theoretical
and practical results are discussed.
Laboratory scale tTestability studies were undertaken to monitor and
optimize the efficiency of biological treatment processes for removing
chlorinated organic material from wastewaters discharged by bleached
kraft pulp mills. The performance of an activated sludge system and
an aerobic stabilization basin were compared to that of a facultative
(anaerobic/aerobic) stabilization basin, in terms of AOX (Adsorbable
Organic Halogen), chlorophenolics and volatile chlorinated organics
removal efficiencies.
40
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
WASTEWATER TREATMENT
NUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
8.25
8.26
8.27
8.28
8.29
8.30
8.31
Reduction of
chlorinated organics
in pulp and paper
mill effluent
Ultrafiltration in
the concentration of
toxic organics from
selected pulp and
paper effluents
Physical/chemical
treatment of bleach-
plant effluents with
the emphasis on
chemical coagulation
Combined biological
and chemical
treatment of kraft
bleach plant
effluent
Indirect steam
gasification of
paper mill sludge
waste
Sludge deuatering
and incineration at
Westvaco, North
Charleston, SC
Blake, N. and
Zuncich, J.
Sludge burning
fluidized bed
boilers
in
Zaidi, A.,
Buisson, H. and
SouriraJen S.
Almemark, H. and
Ekengren, 0.
•Roy-Arcand, L.,
Archibald, F.
and Brfere, F.
Swamy, Warren
and Mansour
James and Kane
Louhimo and
Hullen
TAPPI Proceedings,
1991 Environmental
Conference Book 1,
pp. 445-452
TAPPI Proceedings,
1991 Environmental
Conference Book 1,
pp. 453-468
TAPPI Press,
Environmental
Issues: An
Anthology of 1989,
pp.27-39
TAPPI Press,
Environmental
Issues: An
Anthology of 1989,
pp. 67-74
TAPPI Press,
Environmental
Issues: Anthology
of Published Papers,
1990, pp. 362-370
TAPPI Press,
Environmental
Issues: Anthology
of Published Papers,
1990, pp. 380-389
TAPPI Press,
Environmental
Issues: Anthology
of Published Papers,
1990, pp. 416-431
Laboratory and full scale testing was performed to evaluate the
feasibility of decreasing total chlorinated organic material in pulp
and paper mill effluent via chemical treatment to reduce total
suspended solids, end/or via bio-augmentation. Laboratory
precipitation and bio-augmentation testing was performed on aeration
basin effluent from several mills. Full-scale testing examined AOX
levels before and after bio-augmentation treatment of aeration basin
effluent.
Under the WTC study on UF, several commercial membranes have been
characterized using uniform protocols, and their performance has been
evaluated to determine their effectiveness for separating selected
organics from pulp and paper mill effluents. They include chlorinated
phenolics, lignins, resin acids and dichlorodimethylsulfone. This
paper presents the results from the UTC's work completed to date, and
provides an overview of the published information on the use of UF for
removing organics from pulp and paper mill effluents.
Chemical coagulation vs. Ultrafiltration. Ultrafiltration gives much
the same treatment results for extraction effluents as chemical
coagulation, at least in terms of some parameters. It has until now
been difficult to control membrane filtrate chlorination and total
bleach effluents. Research and development is in progress, however,
and preliminary results are promising.
Many approaches to color and toxic!ty removal from dilute bleach plant
effluent have been tried but the problem still remains for many mills.
The present study investigated the ability of ozone and the white-rot
fungus Coriolus versicolor to reduce E1BE color and toxicity,
separately and in sequence.
Experimental tests were conducted to assess the performance of an
indirectly-heated, fluidized bed, sludge gasification process
employing pulse enhanced heat transfer. This procedure is anticipated
to reduce the amount of dioxin formation which has caused concern
regarding the uncontrolled emissions from incineration systems.
Once the new dewatering system stabilized several trials were
completed on the No. 4 Power Boiler to examine the effect of the
sludge content, in a fuel consisting of bark, chip fines, and sludge,
on thermal efficiency and boiler operation.
The basic design of fluidized bed boilers and the criteria for sludge
as fuel are discussed and examples of both new and retrofit units are
provided.
41
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
WASTEWATER TREATMENT
NUMBER
AUTHOR
REFERENCE
STHOPSIS
8.32
8.33
8.34
8.35
8.36
Sludge incineration:
"The European
Experience"
incineration of
briquetted and .
unbriquetted sludge
Rapid caustic
extraction before an
oxidative extraction
stage
8.37
Dechlorination and
decolonization of
high-molecular-
weight chlorolignin
from bleach plant
effluents by an
oxidation process
Treating bleaching
effluent for
suspended solids and
color
Ultrafiltration for
removing color from
bleach plant
effluent
Hooney and
Helmenstein
Sell, Jayne and
Doshi
Histed, J.A.,
and Canovas, R.
Vega
Sun, Y.B.,
Joyce, U., and
Chang, H.M.
Garcia-Heras,
J.L., and
Forster, C.F.
Lundahl, H., and
Mansson, I.
TAPPI Press,
Environmental
Issues: Anthology
of Published Papers,
1990, pp. 432-440
TAPPI Press,
Environmental
Issues: Anthology
of Published Papers,
1990, pp. 445-458
TAPPI Journal, July
1989, pp. 165-170
TAPPI Journal,
September 1989, pp.
209-213
TAPPI Journal,
September 1989, pp.
199-206
TAPPI Journal, April
1980, p. 97
An overview of sludge burning technology and selected case histories
are presented to illustrate both the state of the art for burning
sludge and the effects of the regulations on both design and cost.
Pilot scale tests of two methods of processing sludge prior to burning
in a hog fuel boiler were compared: screw press dewatering, and screw
press dewatering followed by briquetting and drying.
Rapid caustic extraction, using residual chemicals from an (E+0)
stage, can be achieved in seconds by displacement on a multistage
washer. This process decreases caustic consumption in the (E+0) stage
by about one-third. The use of a multistage washer after the (E+0)
stage results in further savings of bleach chemicals in the succeeding
bleach stages. This technology can be combined with simplified
(0/E/O) bleaching, high-substitution sequential chlorinatSon, and
oxygen prebleaching. At low capital cost, a bleachery can be built
that has low chemical usage, low energy requirements, low chlorine
consumption, and low AOX (absorbable organic halogens) in the
effluents.
The total organic chlorine and color of the high-molecular-weight
chlorolignin form spent alkali extraction-stage effluent were
effectively removed by an oxygen oxidation process. Under the best
conditions, about 70-80X of the TOCl and 60-70X of the color were
removed in less then one hour. A process combining Ultrafiltration,
oxidation, and biological treatment could be an effective, economical
option to remove TOCl and color from spent alkali extraction effluent.
The paper discusses a study of the main characteristics of a
coagulation system to remove chromophoric compounds from a bleach
plant wastewater by iron and calcium cations. The treatment was
successful, with a color removal of 99X with an iron dose of 6-7
moles/m3, the residual suspended solids were low (about 10 mg/l), but
the residual turbidity (5-10 NTU) was higher than the initial value,
and the sludge volume was high (over 20X).
Paper discusses Ultrafiltration for the removal of color from bleach
plant effluents.
42
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
WASTEWATER TREATMENT
NUMBER
TITLE
AUTHOR
REFERENCE
8.38 DechloHnation and
biological treatment
of chlorinated
organic substances
8.39 Effects of secondary
treatment on AOX
levels in kraft mill
effluents
8.40 On-site evaluation
of a teflon-based
ultraviolet light
system and hydrogen
peroxide for the
degradation of color
and chlorinated
organics in Pine E,
from kraft mill
bleach plant
effluents
Bottoer, J.,
Petzold, J.,
Krause, T.H.,
and Schempp,
Dubelsten, P.,
and Grey, N.C.C.
Smith, J.E.,
and Frailey,
M.H.
II.
International
Symposium on Wood
Pulping Chemicals
Proceedings, Paris,
April 27-30, 1987,
Vol. 1, pp. 171-174
CPPA Proceedings,
76th Annual Meeting
Technical Section,
Montreal, Quebec,
February 1-2, 1990,
pp. A317-A324
TAPPI Proceedings,
1990 Environmental
Conference, Seattle,
Washington, April 9-
11, 1990, pp. 101-
110
Treatment of bleach plant effluent by dechlorination, UV and
biological processes reduced AOX by 60X. Post treatment using aerobic
fixed-bed reactor reduced AOX by over 90X.
Curtailing the release of chlorinated bleaching effluent into the
environment has become a major challenge for the Canadian pulp and
paper industry. It is possible that this may be achieved, in part,
with secondary effluent treatment. Aerated lagoons are capable of
reducing chlorinated phenolics by 20-60X and AOX by up to one third.
Improved removal efficiencies of 75-9SX for the chlorinated phenolics
and 50-65X for AOX have been observed with activated sludge treatment.
Data collected from laboratory and field investigations showed that
the UV hydrogen peroxide process could successfully and economically
remove color from Pine Eo filtrate. The reactions were found to be
dependent on both the intensity of UV applied to the system as well as
on the concentration of hydrogen peroxide used. An overall SOX
reduction in apparent color and 85X reduction in AOX was achieved at
operating costs competitive with other technologies. The process did
not produce a sludge.
POLLUTION PREVENTIOM FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
PAPERMAKING
NUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
9.0 PAPERMAKING
9.1 The impact of OSHA
formaldehyde
regulations on
Longview Fibre
Company
9.2 Lower emission urea
formaldehyde resins
9.3 Water reuse program
James-River
Corporation, Curtis
Division
9.4 Wet strength resin
chemistry and
regulatory
considerations
Elliott, R. and
Drapeau, W.
Hart Inez, E. and
Chan, L.
Gremban, Edward
G.
Delaney, N.
TAPPI Press,
Environmental
Issues: An
Anthology of 1989,
pp. 305-306
TAPPI Press,
Environmental
Issues: An
Anthology of 1989,
pp. 307-3K
TAPPI Proceedings,
April 1987
Environmental
Conference, pp. 71-
77
TAPPI Press,
Environmental
Issues: An
Anthology of 1989,
pp. 301-303
Lower "free formaldehyde" urea-formaldehyde type resins were prepared
by different chemical reaction. Emissions of formaldehyde from these
resins and treated paper have been evaluated. The results show that
urea-formaldehyde resins having lower formaldehyde emissions can be
prepared without significant loss in wet strength efficiency.
A study was made of the reuse of paper machine water within the
system. The reuse of the machine water was determined for the
complete paper making process, starting with stock preparation. The
required equipment water was implemented. It was determined that this
reuse of water reduced mill operating costs and resulted in
substantial savings.
An overview of the chemistry involved in the finding of a wet strength
resin containing little or no free formaldehyde will be presented,
with attention to typical performance characteristics and appropriate
applications. How these resin systems may be affected by pending and
future regulations will also be mentioned.
44
POUUTIOM PREVENT ION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
GENERAL PLANT
NUMBER
AUTHOR
REFERENCE
10.0 GENERAL PLANT
10.1
10.2
10.3
10.4
10.5
10.6
Complying with the
kraft pulping
process new source
performance standard
at five West Coast
locations
Reducing waste at
Longview Fibre Co.
Progress in reducing
water use and
wastewater loads in
the U.S. paper
industry
Recycling/ waste
minimization - one
mill's success story
Used oil recycling
at the Champion Mill
in Pensacola,
Florida
Caron, Andre L.
Uhitford, Alan
and Frase, Steve
Miner. Reid and
Unwin, Jay
Edgarley,
Willson
Dai I, H.A. and
Dortch, T.
Means to reduce
effluent pollution
of kraft pulp mills
Gullichsen, J.
E,
TAPPI Journal,
November 1989, pp.
101-105
TAPPI Journal, March
1990, pp. 167-169
TAPPI Proceedings,
1991 Environmental
Conference Book 2,
pp. 639-647
TAPPI Proceedings,
1991 Environmental
Conference Book 2,
pp. 649-652
TAPPI Proceedings,
1991 Environmental
Conference Book 2.
pp. 653-656
TAPPI Proceedings,
1991 Environmental
Conference Book 1,
pp. 185-190
A review of the CEHS records from five lime kilns located at West
Coast mills revealed improved adherence to new source performance
standards.
Ways to reduce waste include washing slaker rejects, recycling wash
thinner from the paint shop, burning primary and secondary clarifier
sludge in the hogged fuel boilers, and improving SBveal Is in the paper
mill.
An important and ongoing part of NCASI's investigative program
involves the periodic collection and organization of information
characterizing the wastes and emissions from the U.S. paper industry.
In this report, information is summarized which documents the
industry's progress in reducing water use, raw waste loads, and final
effluent loads. In addition, the industry's sludge generation rates
and increased reliance on beneficial uses for wastewater treatment
sludges are documented.
The following is an overview of the recycling/waste minimization
program at the James River Corporation Games, Washington paper mill.
Numerous areas of opportunity for savings are identified. Guidelines
for a recycling program are presented. The development of the mill's
solid waste segregation program and a list of a number of elements
which made the program successful will be described.
Champion's Pulp and Paper Mill in Pensacola, like other similar
facilities, has come to recognize that unmanaged used oil is both a
cost and a regulatory liability. Better management of our waste oil
has resulted from a reorganized maintenance program that has, as its
primary emphasis, an ongoing education program and a focus on the
needs of the front-line lubrication mechanics. Unlike in the past,
almost all of our used oil is now accepted for recycling and the cost
of managing the waste oil has been reduced significantly. An
additional benefit is that this enterprise has provided the mill with
a less expensive alternative fuel source that was not originally
anticipated.
Process internal measures alone will not be sufficient to reach
acceptable levels. External effluent treatment will always be
required. Internal abatement measures should concentrate on reducing
pollution potential at the very source but also on improving the
conditions for efficient external treatment.
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
GENERAL PLANT
NUMBER
TITLE
AUTHOR
REFEREHCE
SYNOPSIS
10.7 Feasibility of
municipal wastewater
reuse at a bleached
kraft mill
10.8 Biofiltration - an
innovative control
technology for odors
and air toxics
10.9 Development of toxic
air pollutant
emissions for
thirteen pulp-and
paper mills in
Wisconsin
10.10 Environmental in-
plant control
opportunities for
the kraft process
10.11 "Environmentally
friendly11 processes
in the future
10.12 Selective oxidation
for cost-effective
odor control and
waste minimization
Harrington,
Tantalo, Henry,
Merry and
Ongerth
Leson, G.,
Rickun, J., and
Henson, M.
Fisher, P.,
Foster, J. and
Deb, K.
Kilborn, Jack F.
Axegard, P.
Joyce, W.
TAPPI Proceedings,
1991 Environmental
Conference Book 1,
pp. 197-221
TAPPI Proceedings,
1991 Environmental
Conference Book 1,
pp. 349-354
TAPPI Proceedings,
1991 Environmental
Conference Book 1,
pp. 469-481
TAPPI Proceedings,
April 1987
Environmental
Conference, pp. 65-
69
TAPPI Press,
Environmental
Issues: An
Anthology of 1989,
pp. 133-138
TAPPI Press,
Environmental
Issues: Anthology
of Published Papers,
1990, pp. 390-396
A study of the feasibility of reusing municipal wastewater in the
Simpson Tacoma bleached kraft mill. This paper will report the
results of this study and comment on the application of these
conclusions to the paper industry in general.
Odorous and/or toxic air contaminants ere released from several
processes in pulp and paper mills, including reduced sulfur compounds
(RSC) from kraft pulping, chloroform and formaldehyde. More stringent
emissions control requirements for air toxics and an increasingly
environmentally conscious public could, in the future, require
additional control of these emissions. In many cases, however, the
use of conventional air pollution control technologies will result in
high costs if large air flow rates have to be treated.
Toxic air pollutant emission inventories for combustion sources, pulp
and papermaking operations, storage tanks, and coal. Combustion
related emissions were based upon published emission factors, fuel
analyses, and stack tests spanning a wide spectrum of fuels used in
the pulp and paper industry. The paper also discusses development of
chloroform emissions from pulp bleaching, wastewater treatment plants,
and treatment of incoming water, and formaldehyde emissions from the
application of wet strength resins and combustion of fossil fuels.
Pulp and paper mills have often tolerated undesired water consumption,
chemical and raw material reclaim, and by-product recovery levels
because of limited availability of capital, and because the return on
investment for "fine tuning" plant operations and processes do not
meet a corporate specified "hurdle rate." Because of continued
tightening of mandatory environmental limits, there are overlooked
opportunities for achieving returns on investment with fewer dollars
than would be spent on "end-of-pipe" treatment.
The future "environmentally friendly" system will probably use a
combination of the following steps: modified kraft cooking, oxygen
delignification, replacement of chlorine with chlorine dioxide,
oxidative extraction, anaerobic/aerobic external treatment, membrane
filtration, ozone combined with chlorine dioxide and bleach plant
effluent burnt in the chemical recovery. Continued R&O is necessary.
An evaluation was made on the effectiveness of oxidation and
precipitation to prevention of sulfide generation each with respect to
hydrogen sulfide control, obtaining compliance under (he new OSHA
regulations, and the effect on dewatering operations.
46
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
-------
GENERAL PLANT
NUMBER
TITLE
AUTHOR
REFERENCE
SYNOPSIS
10.13 Stock preparation
energy-saving
measures produce
rapid payback
10.14 Technical and
economic aspects of
measures to reduce
water pollution
caused by the
discharges from the
pulp and paper
industry
10.15 NCM opportunities
for in-plant
reduction of
pollutants through
process changes
10.16 Industry's effluent
problems spawn new
engineering
technology, design
10.17 Closed cycle
technology report
Strobel, S.,
Kohrs, M., and
Siewert, W.H.
COWI consult
Pulp & Paper, April
1988, pp. 49-52
EEC-Contract B6612-
551-88 Final Report,
November 1989
Renard, J.J.,
Phillips, R.B.,
Jameel, H., and
Rudie, A.U.
Galloway, L.R.,
Helminen, P.I.,
end Carter, O.N.
Jain, A.K.
TAPP1 Journal,
August 1981, pp. 51-
54
Pulp & Paper,
September 1989, pp.
91-97
NCASI Report,
September 1988
Pimps and refiners are the largest energy consuners in a typical paper
mill; operating at the highest efficiencies is imperative.
The report is a study of the technical and economical aspects of
measures to reduce Mater pollution caused by the discharges of the
pulp and paper industry. It is intended to be a development document
for a future EEC Directive regulating aqueous discharges from this
industry.
Four process options, including medium-consistency oxygen
delignification, low-Kappa-number kraft/AQ pulping, chlorine dioxide
substitution, and caustic extraction in the presence of oxygen (E0
stage), were compared in terms of production cost, environmental
impact, and product quality. The oxygen-based options were identified
as the most cost effective options to reduce the pollution load of a
bleached kraft mill through process modification.
Article reviews development of environmental regulations for Sweden,
Canada and U.S. Also reviewed are in-plant and external technologies
installed to reduce the discharge of chlorinated organics. These
include extended delignification, oxygen delignification, advanced
pulp washing, C102 substitution, reduced water usage and biological
wastewater treatment.
This report is an assessment of the current state of knowledge of
various closed cycle technologies. Technologies included are Rapson-
Reeve process, Billerud-Uddeholm and other resin processes, activated
carbon absorption, chemical coagulation, ultrafiltration and reverse
osmosis. The report also includes information on the problems
encountered with implementing these technologies, and recommends the
areas of research that could be pursued under the R & D program.
47
POLLUTION PREVENTION FOR THE KRAFT PULP AND PAPER INDUSTRY
------- |