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151. State of the art ECF: pulping and bleaching with oxygen, ozone, and
chlorine dioxide. Part 2.
Homer, Gordon; Johnson, Scott; Epiney, Michel (Air Liquide Canada,
Vancouver, BC, Can.). Pulping Conf., Volume 1, 81-91. TAPPI Press:
Atlanta, Ga. (English) 1996. CODEN: 65XDAV. DOCUMENT TYPE:
Conference; General Review CA Section: 43 (Cellulose, Lignin, Paper,
and Other Wood Products)
A review with 27 refs. The combination of oxygen, ozone, and chlorine
dioxide in pulping and bleaching processes will enhance overall mill
performance and will deliver a very cost effective ECF pulp product.
Aside from its inherent environmental and marketing advantages, such
a combination reduces significantly the consumption of chlorine dioxide
over std. ECF pulp and could be the basis of the "closed" mill without
having to go the TCF route. The use of oxygen delignification has
significant yield advantages over extended cooking. The combination
of ozone and chlorine dioxide in a single stage gives a powerful bleach
sequence that can accommodate much higher Kappa nos. with
corresponding yield increases than the accepted 10 Kappa for TCF
bleaching. The mill implementation of ozone with chlorine dioxide can
be done at low, medium or high consistency. Three mills in Finland,
Brazil and South Africa are proceeding with two of the three processes.
This paper examines oxygen delignification and the impact on yield
and loads to the boiler. The combination of ozone and chlorine dioxide
in high and medium consistency is revisited in existing applications,
and a process to accommodate a low consistency application is
introduced. Uses of the oxygen-rich vent gas from an ozone stage
previously presented is mentioned so that the overall concept can be
economically reviewed on a mill by mill basis.
152. Control methods for spotting disease of sea urchin Strongylocentrotus
intermedius.
Tajima, Kenichi; Hirano, Takahiro; Fujimoto, Saori; Itoh, Singo; Ezura,
Yoshio (Fac. Fish., Hokkaido Univ., Hakodate 041, Japan). Nippon
Suisan Gakkaishi, 64(1), 65-68 (Japanese) 1998 Nippon Suisan
Gakkai. CODEN: NSUGAF. ISSN: 0021-5392. DOCUMENT TYPE:
Journal CA Section: 1 (Pharmacology) Section cross-reference(s): 12
To prevent a loss of cultured sea urchin Strongylocentrotus intermedius
caused by spotting disease, effects of treatments by low temp.,
disinfectants, drugs, UV irradn., and oxidant on the control of growth
and pathogenicity of the causative bacterium, Flexibacter sp. 12-N
using a representative strain were examd. Pathogenicity of the
bacterium was not exhibited in the exptl. infection at 15癈, which was
near the lowest growth temp. of the bacterium. The bacterium showed
high sensitivity to erythromycin, oleandomycin and lincomycin, but was
resistant to kanamycin and nalidixic acid. Susceptibilities of the
bacterium to UV irradn. and oxidant were high, similar to those
reported for fish pathogenic bacteria. Moreover, among the eight
disinfectants tested in vitro, treatment with a 300 ppm hydrogen
peroxide for 5 min at 15癈 was found to disinfect significantly the
bacterium without any injurious effect to the sea urchins.
153. Chemical Reactions in Liquids: Photolysis of OClO in Water.
Thogersen, J.; Thomsen, C. L.; Poulsen, J. Aa.; Keiding, S. R.
(Department of Chemistry, University of Aarhus, Aarhus DK-8000,
Den.). J. Phys. Chem. A, 102(23), 4186-4191 (English) 1998
American Chemical Society. CODEN: JPCAFH. ISSN: 1089-5639.
DOCUMENT TYPE: Journal CA Section: 74 (Radiation Chemistry,
Photochemistry, and Photographic and Other Reprographic
Processes) Section cross-reference(s): 59
The photolysis of aq. OClO, a key reaction in the understanding of atm.
photochem., was studied using femtosecond spectroscopy. These
results resolve the current dispute over the chlorine dioxide photolysis
and provide a detailed and complete example of chem. reaction
dynamics in liqs. Two channels are active in the photolysis: (i) the
formation of Cl atoms with a quantum yield of 0.07 * 0.03 and (ii) the
formation of ClO+O, that geminately recombine as a result of caging
and forms vibrationally excited OClO, which subsequently relaxes to the
vibrational ground state on a 10 ps time scale. By continuously tuning
the photolysis wavelengths from 400 to 300 nm, a gradual increase in
the cage escape yield was obsd., as the kinetic energy of the oxygen
atom becomes sufficient to break the solvent cage.
154. Concurrent bleaching and metal management by addition of EDTA to
chlorine dioxide and ozone stages. Degradation of EDTA and
formation of oxalic acid.
Lindeberg, Otto (MoDo R&D, Ornskoldsvik S-891 80, Swed.). Int. Pulp
Bleaching Conf., Volume 1, 323-330. TAPPI Press: Atlanta, Ga.
(English) 1996. CODEN: 65XBAP. DOCUMENT TYPE: Conference
CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products)
Closing the loop in ECF bleach plants requires a decrease in the
consumption of ClO2. For easily bleached pulps with low kappa nos.,
the decrease can be achieved by switching from a O D(EOP)DED to a
O QPDP or O QPZP sequence. For pulps with higher kappa nos.,
more delignifying power is required. With proper conditions, the Q
stage can be used as a (DQ) stage. In this way, the same tower can be
used both for delignification and metal management for the following
peroxide stage. Similarly, the Z stage can be run as a (ZQ) stage. In
lab trials with (DQ)P bleaching, using a softwood pulp optimum
peroxide, stability was achieved at a charge of 15 kg ClO2 ptp (active
Cl). Acceptable H2O2 residuals were achieved with charges between
10 and 25 kg ClO2 ptp, in spite of an extensive degrdn. of EDTA to
oxalic acid at the highest ClO2 charge. Lab trials with (ZQ)P bleaching,
using a hardwood pulp, showed that the H2O2 residual increased with
an increase in O3 charge from 1 to 5 kg ptp, in spite of an increased
degrdn. of EDTA. The results showed that improved bleaching
sequences can be introduced in old bleach plants without the need for
extra bleach towers or washing equipment.
155. Transition metal removal before a (PO) stage in ECF sequences.
Boman, Rolf; Mellander, Pia; Norden, Solveig (Sunds Defibrator
Industries AB, Sundsvall S-85194, Swed.). Int. Pulp Bleaching Conf.,
Volume 1, 281-285. TAPPI Press: Atlanta, Ga. (English) 1996.
CODEN: 65XBAP. DOCUMENT TYPE: Conference CA Section: 43
(Cellulose, Lignin, Paper, and Other Wood Products)
The use of hydrogen peroxide as a bleaching chem. for kraft pulps has
increased substantially during the latest years, as the general bleaching
trends have moved towards ECF and TCF bleaching technologies.
The recently introduced (PO) bleaching technol. which improves both
delignification and brightening, has rapidly been implemented in com.
scale. There are two main advantages of introducing a (PO) stage in
an ECF sequences. The consumption of active chlorine can be
reduced by 25% when converting a D(EOP)DD sequence to
(DQ)(PO)D. By optimizing the sequence (DQ)(PO)D, the formation of
AOX can be reduced substantially. The first chlorine dioxide stage is
by itself a good way of reducing the manganese content in the pulp. In
most cases however, the redn. is not enough for a good performance of
the (PO) stage. In order to avoid an extra washing stage like in the
sequence DQ(PO)D, other alternative chelating agent treatments have
been investigated. This presentation shows that effective chelating
agent treatments can be performed in the following way: chelating
agent treatment in the high d. storage tower between the oxygen stage
and the bleach plant, like in the sequence OQD(PO)D; combination of
the Q and D stages, like in the sequence (DQ)(PO)D, with sequential
addn. of chlorine dioxide and chelating agent.
156. Interaction of hydrogen peroxide and chlorine dioxide stages in ECF
bleaching.
Senior, D. J.; Hamilton, J.; Ragauskas, A. J.; Froass, P. (ICI Forest
Products, Mississauga, ON L5K 2L3, Can.). Int. Pulp Bleaching Conf.,
Volume 1, 261-273. TAPPI Press: Atlanta, Ga. (English) 1996.
CODEN: 65XBAP. DOCUMENT TYPE: Conference CA Section: 43
(Cellulose, Lignin, Paper, and Other Wood Products)
The order of hydrogen peroxide (P) and chlorine dioxide (D1) stages in
an ECF sequence has been shown to affect the final brightness in
Southern and Northern softwood and eucalyptus kraft pulps. The
Southern softwood pulp bleached using the sequence DEopDPP had
consistently higher interstage and final brightnesses than the
DEopPDP sequence. Northern softwood and eucalyptus pulps were
each bleached using DEDP and DEPD sequences. In each case
higher brightnesses were achieved when the D1 stage preceded the P
stage. The effect was esp. evident with the hardwood pulp where over
3% ISO points higher brightness was seen for the DEDP sequence.
Lignin was extd. from the brownstock, DE-stage, DEP stage and DED
stage pulps and analyzed by 31P NMR. The arom. lignin content of
softwood pulp was reduced by 60% following the D, stage (DED) but
was essentially unchanged when treated by peroxide (DEP). For the
hardwood pulp, lignin content following the D1 stage (DED) was
reduced by 90-95%. The improved bleaching response of the DEDP
pulp in comparison to the DEPD pulp is consistent with documented
reactivities of hydrogen peroxide and chlorine dioxide toward specific
lignin structures. In the DEDP sequence, chlorine dioxide of the D1
stage reduces the arom. content of pulp so that the following hydrogen
peroxide stage can more effectively react with non-arom. species.
Conversely, during bleaching with a DEPD sequence, the P-stage is
less effective in reducing arom. lignin content prior to the D1 stage and
therefore is beneficial to a lesser degree prior to the D1 stage. This
effect is clearly manifested as a lower brightness. It is also reflected as
a reduced sensitivity to bleaching with increasing hydrogen peroxide
charges.
157. (DZ) and (ZD) bleaching: fundamentals and application.
Chirat, Christine; Lachenal, Dominique; Angelier, Robert; Viardin,
Marie-Therese (Centre Technique du Papier, Domaine Universitaire,
Grenoble 38044, Fr.). Int. Pulp Bleaching Conf., Volume 1, 197-202.
TAPPI Press: Atlanta, Ga. (English) 1996. CODEN: 65XBAP.
DOCUMENT TYPE: Conference CA Section: 43 (Cellulose, Lignin,
Paper, and Other Wood Products)
Combinations of O3 and ClO2 in (DZ) or (ZD) stages in replacement of
D stages can be very efficient in terms of chem. savings as well as in
decreasing the AOX generated during ECF bleaching of kraft pulps.
(DZ) was superior to (ZD) when applied on an unbleached pulp,
whereas the contrary was obsd. when they were implemented on an
O-bleached pulp. The chem. structure of the lignin (I), as well as the
chem. of both reagents with this residual I could explain these results.
Lab. and pilot trials showed that 1 kg of O3 could substitute for *3 kg of
ClO2. AOX formation was decreased as a consequence of the
decrease in ClO2 charge. Min. AOX was formed when neutralization
was performed between Z and D in (ZD). The choice between (DZ)
and (ZD) will depend mainly on the existing installation or on the
process.
158. Degradation of dirt particles by kraft pulp bleaching reagents.
Francis, R. C.; Devenyns, J. (SUNY College of Environmental Science
and Forestry, ESPRI, Syracuse, NY 13210, USA). Int. Pulp Bleaching
Conf., Volume 2, 619-622. TAPPI Press: Atlanta, Ga. (English) 1996.
CODEN: 65XBAP. DOCUMENT TYPE: Conference CA Section: 43
(Cellulose, Lignin, Paper, and Other Wood Products)
Six kraft pulp bleaching reagents were investigated to see how
effective they were at removing dirt particles. The dirt particles were
obtained from kraft pulping rejects and were added to a partially
bleached, com. softwood kraft pulp with kappa no. 2.0 and brightness
61.4% Elrepho. The rejects, primarily shives and knots, were
disk-refined at low plate clearance to decrease the av. size of the fiber
bundles. After refining, the rejects had a Canadian Std. Freeness
(CSF) of 650 mL and a kappa no. of 83. Dirt bleaching was monitored
by quantifying residual particles using an image anal. method
standardized against Tappi Method T 213 om-89, and by measuring
the decrease in bleached brightness or increase in light absorption
coeff. when the reject content was increased from 1.0% to 3.0% on
pulp. The 6 reagents were ClO2 (D), O (O), H2O2 (P), O3 (Z), Caro's
acid (K), and peracetic acid (PAA). The ranking was
PAA=D>K>P>O=Z. The 2 most effective oxidants (PAA and D) were
effective delignifiers and brighteners. Also, unlike O3, they were not
rapidly consumed. Caro's acid was a less effective brightener, while
H2O2 was a less effective delignifier. The poor ranking for O was
caused by its inability to completely de-lignify the 83 kappa no.
particles that were used. O3 was ineffective because of its high
reactivity; it was consumed before it had time to diffuse into some dirt
particles with low porosity.
159. Reactions of some monoterpenes with chlorine dioxide.
Reeve, Douglas W.; Xi, Fred; Tong, Denise H. Y.; McKague, A. Bruce
(Department of Chemical Engineering and Applied Chemistry and Pulp
& Paper Centre, University of Toronto, Toronto, ON M5S 3E5, Can.).
Int. Pulp Bleaching Conf., Volume 2, 613-617. TAPPI Press: Atlanta,
Ga. (English) 1996. CODEN: 65XBAP. DOCUMENT TYPE:
Conference CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood
Products)
The residual monoterpenes in pulp entering the bleach plant may react
with Cl-contg. bleaching agents to form chlorinated products. The
chem. structures of products from reactions of several monoterpenes
with ClO2 were detd. In the 1st stage of research, pure a-pinene (I) and
p-cymene (II) were reacted with aq. ClO2 at 75* for 3.5 h. The products
were sepd. and analyzed by gas chromatog. mass spectrometry and
NMR spectrometry. 2-Chlorobornane-6-one was identified as the
major product from the reaction of I with ClO2. 9-Chloro-p-cymen-8-ol
(III) was the major product from reaction of II with ClO2. Minor amts. of
other mono- and dichlorinated reaction products were also found. In
the 2nd part of the work, softwood kraft pulp was impregnated with II
and bleached with ClO2; III was not found in the D-stage filtrate. These
studies showed that, even with aggressive treatment, the main
chlorinated products from the reaction of monoterpenes with ClO2 are
only monochlorinated. It was therefore concluded that, under the much
milder conditions found in pulp bleaching with ClO2, highly chlorinated
products will not be produced.
160. Optimization of ClO2 use in ECF bleaching.
Euphrosine-Moy, V.; Pouillot, M.; Suty, H. (Elf Atochem S.a., Levallois
92300, Fr.). Int. Pulp Bleaching Conf., Volume 2, 421-423. TAPPI
Press: Atlanta, Ga. (English) 1996. CODEN: 65XBAP. DOCUMENT
TYPE: Conference CA Section: 43 (Cellulose, Lignin, Paper, and Other
Wood Products)
The purpose of the study was to find operating conditions of ECF
(elementary Cl-free) DEopDD bleaching of oxygen-delignified
softwood kraft pulp to ensure high brightness with the min. of AOX
(absorbable org. halogen compds.) content. High brightness
(88.5-89% ISO) can be achieved even with a reduced kappa factor.
The amts. of ClO2 required in the last stages are higher than in the ref.,
but the total amt. fo ClO2 remains const. When ClO2 charge is
redistributed to the final stages, AOX levels are reduced by 67%. Low
AOX levels ~o.2 kg/ton are measured before any effluent treatment.
Reinforcing the extn. stage with H2O2 is a way to ensure high brightness
with brightness gain up to 0.9% ISO. Splitting the charge of ClO2 can
also improve the efficiency of ClO2.
161. Reduction of the formation of AOX during chlorine dioxide bleaching.
Lachenal, D.; Joncourt, M. J.; Froment, P.; Chirat, C. (Ecole Francaise
de Papeterie et des Industries Graphiques, St. Martin d'Heres 38402,
Fr.). Int. Pulp Bleaching Conf., Volume 2, 417-420. TAPPI Press:
Atlanta, Ga. (English) 1996. CODEN: 65XBAP. DOCUMENT TYPE:
Conference CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood
Products) Section cross-reference(s): 60
Formation of adsorbable org. halogen compds. (AOX) during ClO2
bleaching of pulp could be decreased by adding chems. which reacted
selectively with ClOH (or Cl2) generated during the process. However,
2 problems were found, i.e., (A) the quantity of ClOH formed during
ClO2 delignification was large and represented 70% of the initial ClO2
charge (on a molar basis); consequently high charges of additive will
be necessary, and (B) destruction of ClOH had an adverse effect on
bleaching; ClOH would contribute to one third of the delignification
obsd. in the presence of ClO2. Addn. of Fe2+, which was supposed to
favor the generation of ClO2 from HClO2, had a neg. effect on
delignification and caused viscosity loss.
162. SVP-GLS a novel method of producing salt cake free chlorine dioxide.
Sundstrom, Goran; Hammer-Olsen, Roy; Falgen, Helena; Landfors,
Johan; Sokol, John (EKA CHEMICALS AB, Sundsvall, Swed.).
Pulping Conf., Volume 2, 915-921. TAPPI Press: Atlanta, Ga. (English)
1996. CODEN: 65XDAV. DOCUMENT TYPE: Conference CA
Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products)
One remaining issue for ClO2 technol. in closed loop mills is the
formation of byproduct Na2SO4, which cannot be used as a make-up
chem. in a more closed pulp mill. Results from lab and pilot tests show
that a ClO2 generator can be integrated with a salt splitter to give an
efficient process that is easy to control and has low operating costs.
SVP-GLS is a salt cake-free ClO2 process, operating without any
solids, and thus, without the formation of Na2SO4 byproduct. In the
Generator Liquor Split (GLS) process, the generator liquor is
electrochem. acidified, with a simultaneous prodn. of 0.6 ton NaOH per
ton ClO2. The co-produced NaOH (~15 wt.%) can be used anywhere in
the mill to replace com. NaOH. With chlorate, reducing agent, and elec.
energy as the only raw materials, SVP-GLS is able to produce ClO2
without byproduct Na2SO4. SVP-GLS also provides superior
performance with respect to energy balance, prodn. capacity, prodn.
economy and ease of operation compared with other salt-free ClO2
prodn. alternatives. Because of the superior water balance in the
SVP-GLS system, the water load on the ClO2 generator is decreased
by *70%.
163. Chlorine dioxide reduction in ECF bleaching of kraft pulp to high
brightness through a low capital enhancement of EOP extraction.
Stevens, Jeff A.; Hsieh, Jeffery S. (Pulp and Paper Engineering School
of Chemical Engineering, Georgia Institute of Technology, Atlanta, GA
30332-0100, USA). Pulping Conf., Volume 2, 663-674. TAPPI Press:
Atlanta, Ga. (English) 1996. CODEN: 65XDAV. DOCUMENT TYPE:
Conference CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood
Products)
100% Chlorine dioxide substitution followed by oxidative alk. extn. is
rapidly becoming the chief method of kraft pulp delignification for
elemental chlorine-free (ECF) bleaching. This D0Eop process can be
improved so that less ClO2 is required in the initial D0 stage to achieve
full brightness after ECF bleaching, thus reducing formation of
chlorinated org. compds. while reducing the ClO2 generator capacity
required to reach full brightness. This work describes a process where
sodium nitrite under acidic conditions is added just after the D0 stage,
without interstage washing, to "activate" the pulp for subsequent Eop
extn. and D1D2 bleaching to full brightness. Using this technique, the
kappa factor can be reduced from .18 to .15, while using only 1.3%
ClO2 in the two downstream brightening stages to achieve 90
brightness.
164. Density functional calculations of heats of reaction.
Politzer, Peter; Wiener, John J. M.; Seminario, Jorge M. (Department
of Chemistry, University of New Orleans, New Orleans, LA 70148,
USA). Theor. Comput. Chem., 4(Recent Developments and
Applications of Modern Density Functional Theory), 811-824 (English)
1996 Elsevier Science B.V. CODEN: TCCHFN. DOCUMENT TYPE:
Journal CA Section: 69 (Thermodynamics, Thermochemistry, and
Thermal Properties)
The DF/B3P86/6-31+G** procedure was used to calc. the energies
(and zero-point corrections) at 0 K and the enthalpies and heat
capacities at 298 and 800 K for 92 atoms, mols. and ions, generally of
fragments typically contg. large proportions of the electron-rich atoms
N, O, F and/of Cl, many of these being intermediates or products
obtained in the dissocn. of energetic mols.
165. Energies and structures of isomers of Cl2O2 calculated by density
functional methods.
Han, Young-Kyu; Hoon Kim, Kyoung; Sup Lee, Yoon; Baeck, Kyoung K.
(Dep. of Chem., Cent. for Mol. Sci., Korea Adv. Inst. of Sci. and
Technol., Taejon 305-701, S. Korea). THEOCHEM, 431(1-2), 185-189
(English) 1998 Elsevier Science B.V. CODEN: THEODJ. ISSN:
0166-1280. DOCUMENT TYPE: Journal CA Section: 65 (General
Physical Chemistry)
The geometries and the relative energies of three low-lying (ClO)2
isomers in the ground state were calcd. using d. functional theory (DFT)
methods. The DFT relative energies using extended basis sets vary by
*4.5 cal/mol, depending upon the functionals employed, but differ by
<2.5 cal/mol from the available CCSD(T) results with large at. natural
orbital basis sets. DFT calcd. geometries of the isomers are also in
reasonable agreement with expt. The DFT methods could be used to
study relative energetics of (ClO)2 isomers, for which large basis sets
are essential even for modest accuracy.
166. In-the-eye use of chlorine dioxide-containing compositions.
Ripley, Paul S.; Dziabo, Anthony J.; Anger, Claude B. (Allergan, USA).
U.S. US 5736165 A 7 Apr 1998, 7 pp. Cont.-in-part of U.S. Ser. No.
66,746, abandoned. (English). (United States of America). CODEN:
USXXAM. CLASS: ICM: A61K033-20. ICS: A61K033-40;
A01N059-00. NCL: 424661000. APPLICATION: US 94-277718 20
Jul 1994. PRIORITY: US 93-66746 25 May 1993. DOCUMENT TYPE:
Patent CA Section: 63 (Pharmaceuticals)
Disclosed are in-the-eye uses of ClO2-contg. compns. as effective
ophthalmic antiseptics and for effective ophthalmic surgical irrigation.
Surprisingly low concns. of ClO2 are effective in such applications. In
addn., the presently useful compns. are ophthalmically acceptable. To
a conventional borate-buffered saline soln. was added a stabilized
ClO2 (Purogene) to produce 5 ppm ClO2. The resulting soln. had a pH
of about 7.3, was substantially isotonic, and was ophthalmically
acceptable.
167. A balanced view of chlorine dioxide.
Gates, Don J. (DG Consulting Inc., Citrus Heights, CA 95621, USA). J.
- Am. Water Works Assoc., 90(4), 8, 10 (English) 1998 American
Water Works Association. CODEN: JAWWA5. ISSN: 0003-150X.
DOCUMENT TYPE: Journal; General Review CA Section: 61 (Water)
The use of chlorine dioxide in the disinfection of drinking water is
reviewed with no refs.
168. Water processing. Potential hazards in the handling of disinfectants.
Anon. (Berufsgenossenschaft Gas-, Fernwaerme- Wasserwirtschaft,
Duesseldorf D-40225, Germany). Neue DELIWA-Z., 49(3), 98-99
(German) 1998 DELIWA-Verein e.V. CODEN: NEUDAA. ISSN:
0341-0323. DOCUMENT TYPE: Journal; General Review CA Section:
59 (Air Pollution and Industrial Hygiene) Section cross-reference(s): 4,
61
A review without refs. on safety measures as to the different
disinfection methods currently applied for water treatment including
treatment with Cl gas, ClO2, NaOCl, and O3. The properties of the
resp. disinfectants, the health risk, and the corresponding protective
measures and clothing are described.
169. Disproportionation of Chlorous Acid at a Strong Acidity.
Ni, Y.; Yin, G. (Dr. Jack McKenzie Limerick Pulp and Paper Research
and Education Centre, University of New Brunswick, Fredericton E3B
6C2, Can.). Ind. Eng. Chem. Res., 37(6), 2367-2372 (English) 1998
American Chemical Society. CODEN: IECRED. ISSN: 0888-5885.
DOCUMENT TYPE: Journal CA Section: 49 (Industrial Inorganic
Chemicals) Section cross-reference(s): 67
Com. chlorine dioxide generators are operated in an about 4.5-mol/L
sulfuric acid soln. The chlorous acid disproportionation may be an
important pathway to generate chlorine dioxide under such a condition.
On the basis of the product detn., we found that, in the absence of a
chloride ion, chloric acid, hypochlorous acid, and chlorine, rather than
chlorine dioxide, are the products from the chlorous acid
disproportionation. However, chloride addn. to the chlorous acid soln.
under otherwise the same condition results in the generation of chlorine
dioxide. The underlying mechanism of the chloride effect on the
chlorous acid disproportionation is discussed.
170. Brightness development in the final ClO2 stages of an ECF kraft pulp
bleaching sequence: modeling and effects of pulping conditions.
McDonough, Thomas J. (Institute of Paper Science and Technology,
Atlanta, GA, USA). Pulping Conf., Volume 1, 201-205. TAPPI Press:
Atlanta, Ga. (English) 1996. CODEN: 65XDAV. DOCUMENT TYPE:
Conference CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood
Products)
To gain an understanding of the factors that det. bleachability in the final
stages of an elemental chlorine-free bleaching sequence, conventional
and modified kraft pulps were prepd. in the lab. and bleached in a
D0(EO)D1ED2 sequence with varied applications of ClO2 in the D, and
D2 stages. After delignification at a const. kappa factor, the extent of
D1 brightening was detd. by ClO2 consumption and pulp type, but not by
unbleached kappa no. For a given brightness after the D1 stage,
modified pulping produced pulps that consumed less ClO2 than
conventional pulps. Brightening in the D2 stage was described by a
simple equation relating final brightness to ClO2 consumed. The
parameters in this equation may be interpreted in terms of a brightness
ceiling and a rate of approach to the brightness ceiling, termed the D2
response factor. The brightness ceiling increased with increasing
levels of brightness entering the D2 stage, and was higher for modified
than for conventional pulps. The response factor decreased as the
entering brightness was increased and was higher for pulps of lower
unbleached kappa no.
171. Peracetic acid in low AOX and high brightness pulp production.
Jakara, J.; Paren, A.; Renvall, I.; Aksela, R. (Kemira Chemicals Oy,
Vaasa R & D Lab., Vaasa, Finland). Kami Pa Gikyoshi, 52(4),
485-492 (Japanese) 1998 Kami Parupu Gijutsu Kyokai. CODEN:
KAGIAU. ISSN: 0022-815X. DOCUMENT TYPE: Journal CA Section:
43 (Cellulose, Lignin, Paper, and Other Wood Products)
The effects of chelating agents, peracetic acid (PAA) and alk. peroxide
on the replacement of chlorine dioxide and hypochlorite in D-E0-H-D
bleaching of oxygen delignified hardwood kraft pulp were studied in a
lab. scale. Since an increased use of peroxygen chems. necessitates
a use of a chelating agent, both DTPA (diethylene triamine pentaacetic
acid) and a new chelating agent with low nitrogen content [diethanol
amine succinate (DEAS)] were tested. Peracetic acid was used here
as a bleaching agent in combination with chlorine dioxide in a D2
stage. Also the effect of peracetic acid on post-bleaching of
O-D-EOP-D bleached softwood kraft pulp was studied. The bleaching
expts. indicate that the importance of a chelation prior to E0 stage
increases with the decreasing active chlorine charge in the D1 stage
and increasing peroxide charge in the E0 stage. With a sequence of
Q/D-EOP-Q/D/PAA the total active chlorine charge in D-E0-H-D
dropped from 48 kg act. Cl/tp to 20 kg act. Cl/tp by using 10 kg H2O2/tp
in the E0 stage and 5 kg peracetic acid/tp in the D2 stage. Also 8 kg
hypochlorite/tp were eliminated at the same time. The use of DEAS in
the Q/D stage gave more improved pulp properties for bleached pulp
than the use of DTPA correspondingly.
172. Particle removal with chlorine-free bleaching chemicals.
Bergnor, Elisabeth; Strom, Maria; Mellander, Pia (STFI, Swedish Pulp
and Paper Research Institute, Stockholm S-114 86, Swed.). Int. Pulp
Bleaching Conf., Volume 1, 63-70. TAPPI Press: Atlanta, Ga. (English)
1996. CODEN: 65XBAP. DOCUMENT TYPE: Conference CA
Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products)
This paper considers the efficiency of particle removal with
chlorine-free bleaching chems. when producing fully bleached softwood
kraft pulps. Comparisons are made between bleaching with hydrogen
peroxide, peracetic acid, ozone, and chlorine dioxide. The reaction
patterns for the bleaching agents were studied when shives and fibers
were treated in sep. expts. Also, the efficiency of particle removal in
TCF and ECF sequences were compared when shives or knots were
added to particle- free pulp before bleaching. Our results show that
hydrogen peroxide in a QP-sequence is very efficient in removing
particles at a given delignification degree. Furthermore, in a
microscopic study, we found that the reaction pattern for hydrogen
peroxide in a QP-bleaching position is similar to that of chlorine
dioxide, as the delignification seems to occur evenly across the shive.
On the contrary, ozone bleaching of shives is an extreme surface
reaction; hence, the particle thickness should be even more crit. when
bleaching with ozone than with other bleaching chems. In a QPQ(PO)*
sequence, it is possible to obtain the same degree of shive elimination
as with ECF bleaching. If an ozone or peracetic acid stage precede a
final hydrogen peroxide stage, problems with pulp cleanliness may
appear. However, mech. treatment after final bleaching seems to
improve shive elimination in all TCF sequences. This suggests that
shive elimination in TCF bleaching can be as effective as in ECF
bleaching.
173. Problems of interinfluence of some components in bleaching systems.
Sokolov, V. V. (St.-Petersburg State Technological, University of Plant
Polymers, St.-Petersburg 198095, Russia). Int. Pulp Bleaching Conf.,
Volume 2, 353-355. TAPPI Press: Atlanta, Ga. (English) 1996.
CODEN: 65XBAP. DOCUMENT TYPE: Conference CA Section: 43
(Cellulose, Lignin, Paper, and Other Wood Products)
Simultaneous presence of some pollutants in bleaching systems of pulp
and paper industry, their thermodn. characteristics, qual. and quant.
estn. of phenomenon of synergism is discussed.
174. Ab initio study of isomerism in LAB2 salt molecules with 18 and 20
valence electrons.
Charkin, O. P.; McKee, M. L.; Klimenko, N. M.; Schleyer, P. v. R. (Inst.
Nov. Khim. Probl., RAN, Chernogolovka, Russia). Zh. Neorg. Khim.,
43(2), 294-302 (Russian) 1998 MAIK Nauka. CODEN: ZNOKAQ.
ISSN: 0044-457X. DOCUMENT TYPE: Journal CA Section: 65
(General Physical Chemistry) Section cross-reference(s): 67
Ab initio potential energy surfaces, geometries, isomer relative
energies, IR intensities and vibrational frequencies are presented for
LAB2 salts (L = Li, Na), LiNO2, LiPO2 LNS2, LPS2, LClO2, and LiS3+,
LiSO2+ ions. The authors used MP2/6-31G*//HF/6-31G* +
ZPE(HF/6-31G*) and MP4SDTQ/6-31G*//MP2/6-31G* +
ZPE(MP2/6-31G*) methods.
175. Classification of algogenic organic matter concerning its contribution to
bacterial regrowth potential and byproducts formation.
Schmidt, Wido; Hambsch, Beate; Petzoldt, Heike
(DVGW-Technologiezentrum Wasser Karlsruche (TZW), Dresden
D-01139, Germany). Water Sci. Technol., 37(2, Reservoir
Management and Water Supply: An Integrated System), 91-96
(English) 1998 Elsevier Science Ltd. CODEN: WSTED4. ISSN:
0273-1223. DOCUMENT TYPE: Journal CA Section: 61 (Water)
Section cross-reference(s): 10
The bacterial regrowth potential (BRP) and the byproducts formation
potential after the disinfection (DBP) are parameters recognized to be
influenced by the origin of org. matter dissolved in water. A significant
difference of the impact of humic compds. and algogenic org. matter
(AOM), characteristic for raw waters from reservoirs, to both
parameters can be assumed. In systematic lab. expts. the influence of
AOM on the BRP as well as DBP was examd. Different fractions of the
AOM were chlorinated and treated with chlorine dioxide. In addn. to
that the influence of the ozonation was investigated. To assess the
biodegradable fraction of the org. matter (BDOC) a large spectrum of
byproducts (aldehydes and keto-acids) was analyzed. The BRP in the
water was detd. by the measurement of the increase of biomass in the
water samples. It could be proved, that the chlorination of intact algae
cells contg. waters may cause a significant increase of the
biodegradability in the water if the residual chlorine is totally required.
In the case of the disinfection of the AOM contg. waters with chlorine
dioxide the relative increase of the BRP was lower in comparison to the
chlorinated waters. The preozonation of the algae contg. waters
indicates an addnl. increase of the BRP, but only by ozonation of the
algae cells. The ozonation of the algae metabolites does not influence
the BRP, but it causes a significant decrease of the THM-formation if
chlorine is used for disinfection.
176. Application of chlorine dioxide as an oilfield facilities treatment fluid.
Romaine, Jennifer; Strawser, T. G.; Knippers, M. L. (Rio Linda
Chemical Co., Inc., USA). Proc. - Int. Symp. Oilfield Chem., 761-771.
Society of Petroleum Engineers: Richardson, Tex. (English) 1995.
CODEN: 65WIA7. DOCUMENT TYPE: Conference CA Section: 51
(Fossil Fuels, Derivatives, and Related Products)
This paper describes the design and operation of using chlorine
dioxide for the removal of iron sulfide sludge from water flood injection
distribution systems. 4,500 Barrels of chlorine dioxide was pumped in
three phases to clean sixty six miles of the water flood distribution
system. Results indicate that chlorine dioxide was effective in cleaning
the well guard screens, the injection lines, frac tanks used to collect the
treatment fluids and the injection wells.
177. Delignification and bleaching of chemical pulp.
Devenyns, Johan; Chauveheid, Eric (Solvay Interox (Societe Anonyme);
Devenyns, Johan; Chauveheid, Eric, Belg.). PCT Int. Appl. WO
9816683 A1 23 Apr 1998, 20 pp. DESIGNATED STATES: W: AL,
AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK,
EE, ES, FI, GB, GE, HU, ID, IL, IS, JP, KE, KG, KP, KR, KZ, LC, LK,
LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO,
RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU,
ZW, AM, AZ, BY, KG, KZ, MD, RU, TJ, TM; RW: AT, BE, BF, BJ, CF,
CG, CH, CI, CM, DE, DK, ES, FI, FR, GA, GB, GR, IE, IT, LU, MC, ML,
MR, NE, NL, PT, SE, SN, TD, TG. (French). (World Intellectual Property
Organization). CODEN: PIXXD2. CLASS: ICM: D21C009-10.
APPLICATION: WO 97-EP5309 25 Sep 1997. PRIORITY: BE 96-859
11 Oct 1996. DOCUMENT TYPE: Patent CA Section: 43 (Cellulose,
Lignin, Paper, and Other Wood Products)
The title process, which requires no chelation step, comprises acid
treatment of the pulp to decrease hexeneuronic acids by *10%,
adjusting the pH to (re)deposit alk.-earth metal ions on the pulp,
washing, and treating the pulp with an oxidizing agent; a soln. high in
alk.-earth metal ions and poor in transition metal ions being added
before, during, and/or after 1 of these steps. Heating a 12% pulp slurry
at pH 3.0 for 2 h at 110*, neutralizing to pH 7, adding a soln. of 0.4%
MgSO4 and 0.3% CaCl2 (based on pulp), washing, and oxidizing with
H2O2 at pH 11 gave pulp with ISO whiteness 79.7; vs. 72.5 when
chelation was used rather than alk. earth ion addn.
178. Chlorine dioxide bleaching -- a case study.
Satyanarayana Rao, P. V. V.; Sagar, V. V.; Bapuji, G.; Gupta, P. K.
(Andhra Pradesh Paper Mills Ltd., Rajahmundry 533 105, India).
IPPTA, (Conv. Issue), 27-31 (English) 1997 Indian Pulp and Paper
Technical Association. CODEN: IPPTDO. ISSN: 0379-5462.
DOCUMENT TYPE: Journal CA Section: 43 (Cellulose, Lignin, Paper,
and Other Wood Products)
The various practical difficulties encountered by an Indian paper mill in
changing over from a conventional C-Ep-H-H bleaching sequence to a
C-Ep-D-E-D sequence, and the measures undertaken in surmounting
some of the difficulties to meet the set targets of higher pulp brightness
with better brightness stability, less pollution, and product quality
up-gradation, are discussed. In downward tower design, absorption of
the ClO2 by the pulp at higher dosages was less and led to ClO2
emissions. In such a situation, pulp brightness of 84.0%+ with better
strength properties could be obtained with C-Ep-D-E/H-D-SO2
sequence, facilitating the use of this high-brightness pulp for
high-brightness paper grades. By introducing peroxide in the E1 stage
and hypo in the E2 stage, a savings of ClO2 and a decrease of color in
the alkali backwater effluent could be achieved.
179. Modifying existing bleach plants for ECF sequences with low chlorine
dioxide.
Jameel, Hasan; Chang, Hou-Min; Geng, Z. P. (Department of Wood
and Paper Science, North Carolina State University, Raleigh, NC
27695-8005, USA). Pulping Conf., Volume 2, 651-661. TAPPI Press:
Atlanta, Ga. (English) 1996. CODEN: 65XDAV. DOCUMENT TYPE:
Conference CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood
Products)
As pulp mills convert their bleaching systems to elemental Cl-free
(ECF) sequences, the simplest soln. is to increase the ClO2 capacity.
A typical mill bleaching softwood has available ~1.5% ClO2, but this
capacity would have to be increased to 4% to achieve ECF by the
conventional approach. Other options to achieving ECF bleaching,
without increasing the ClO2 capacity are presented. H2O2 can be
substituted for ClO2, since it is readily available at the mill, and min.
capital is required for its implementation. It is very important to control
the metal ion profile in pulps to optimize the performance of H2O2.
A(PDTMP) and (AQ)P are used to minimize the decompn. of peroxide.
The sequence chosen was D(PO)DDP, since it can be retrofitted into
an existing (CD)(EOP)DED bleach plant. A brightness of 87% ISO can
be achieved using 31 kappa no. pulp with 1.5% ClO2 and 2% H2O2.
The (PO) stage can either be a fully pressurized system or a (PO)ht
system with shortened retention time under pressure and higher temps.
As a result, a mill may want to evaluate this option for achieving ECF
bleaching, instead of investing in addnl. ClO2 capacity. If addnl.
decreases in color, AOX, and COD are desired, a sequence such as
(AQ)(PO)DDP can be chosen. This sequence can also be easily
retrofitted into an existing (CD)(EOP)DED bleach plant. A brightness
of 85% ISO could be achieved using 0.7% ClO2 and 3% H2O2 with a 31
kappa no. pulp. In the above sequence, the filtrate for the (AQ)(PO)
stages can be recycled back to the recovery system.
180. Study of the Stability of BrClO3 Isomers.
Francisco, Joseph S.; Clark, Jason (Department of Chemistry and
Department of Earth and Atmospheric Sciences, Purdue University,
West Lafayette, IN 47907-1393, USA). J. Phys. Chem. A, 102(12),
2209-2214 (English) 1998 American Chemical Society. CODEN:
JPCAFH. ISSN: 1089-5639. DOCUMENT TYPE: Journal CA Section:
67 (Catalysis, Reaction Kinetics, and Inorganic Reaction Mechanisms)
Section cross-reference(s): 53, 65, 69, 73
The structures, vibrational frequencies, and rotational consts. have
been detd. using ab initio methods of isomers of BrClO3. The
BrOCl(O)O structural form is found to be the most stable. This species
could be formed from the three-body reactions involving BrO + OClO +
M * BrOCl(O)O + M and Br + ClO3 + M * BrOCl(O)O + M. The heats
of reaction for these processes are estd. to be -8.2 and -24.4 kcal
mol-1, resp.
181. Bonding properties of chlorine oxide ClOx (x = 1-4) in the density
functional theory.
Janoschek, Rudolf (Inst. Theor. Chem., Karl-Franzens-Univ., Graz
A-8010, Austria). THEOCHEM, 423(3), 219-224 (English) 1998
Elsevier Science B.V. CODEN: THEODJ. ISSN: 0166-1280.
DOCUMENT TYPE: Journal CA Section: 65 (General Physical
Chemistry)
The geometries, energies, heats of formation and bond dissocn.
energies of the chlorine oxides ClOx (x = 1-4) were computed at the
restricted open shell BECKE3LYP/cc-pV5Z level; vibrational
wavenumbers and intensities were calcd. employing the cc-pVQZ
basis set. The mean abs. deviation between the calcd. and newest
exptl. enthalpies of formation was 5.3 kJ mol-1. A tetrahedral-like C2v
min. geometry of the recently described ClO4 radical was calcd.,
whereas the hitherto assumed C3v structure was characterized as an
energetically higher-lying second-order saddlepoint.
182. Degradation of herbicides (ametryn and isoproturon) during water
disinfection by means of two oxidants (hypochlorite and chlorine
dioxide).
Lopez, A.; Mascolo, G.; Tiravanti, G.; Passino, R. (Consiglio Nazionale
delle Ricerche, Istituto di Ricerca Sulle Acque, Bari 70123, Italy). Oxid.
Technol. Water Wastewater Treat., Int. Conf., Paper 61, pp. 8. Edited
by: Vogelpohl, Alfons. Papierflieger Verlag: Clausthal-Zellerfeld,
Germany. (English) 1996. CODEN: 65VMAE. DOCUMENT TYPE:
Conference CA Section: 61 (Water)
The paper reports the results of an investigation aimed to find out the
no. and the chem. structures of byproducts which form during the
reactions occurring in aq. soln. between two very common
disinfectants, sodium hypochlorite (NaClO) and chlorine dioxide (ClO2),
and two herbicides widely used in agriculture and frequently found into
groundwaters: ametryn and isoproturon. Under controlled exptl.
conditions [20*, pH 7, reaction time 48h, herbicide/disinfectant molar
ratios: 0.05 and 0.05*10-2], ametryn reactions with chlorine dioxide are
much slower than with sodium hypochlorite, whereas the opposite trend
has been obsd. for isoproturon. In any case, however, the higher the
reagents concn. the faster the reactions. As for reactions byproducts,
they have been detected by HPLC and identified by HPLC-MS. In
particular, ametryn (R-S-CH3) reaction with NaClO gives rise to the
consecutive formation of four derivs.: the sulfoxide (R-SO-CH3), the
sulfone (R-SO2-CH3), the sulfonate ester (R-O-SO2-CH3) and its
hydrolysis product (R-OH). Within the fixed reaction time (48h),
ametryn reaction with ClO2 forms only the sulfoxide deriv. (R-SO-CH3).
As for isoproturon, it reacts with both oxidants forming arom.-ring
substituted derivs. In particular, during the reactions with NaClO and
ClO2, four and two (chlorinated and/or hydroxylated) derivs. are resp.
formed.
183. Improved water quality by process renewal in a pulp and paper mill.
Kaplin, Camilla; Hemming, Jarl; Holmbom, Bjarne (Laboratory of
Forest Products Chemistry, Abo Akademi University, Turku FIN-20500,
Finland). Boreal Environ. Res., 2(3), 239-246 (English) 1997 Finnish
Zoological and Botanical Publishing Board. CODEN: BEREF7. ISSN:
1239-6095. DOCUMENT TYPE: Journal CA Section: 61 (Water)
Section cross-reference(s): 43, 60
The Kaukas pulp and paper mill on southern Lake Saimaa (Finland)
was investigated to evaluate the environmental benefits of process
renewal, i.e., the substitution of chlorine by chlorine dioxide in the
bleaching and the modernization of the biol. effluent treatment. A
comparative study of the mill effluent and the catchment water area was
performed before (1991) and after (1993/1995) the changes. The
chem. compn. of the mill effluent was analyzed, with special emphasis
on chlorinated orgs. and wood extractives. The same compds. were
detd. in lake waters with respect to distribution and persistence. The
study revealed a considerable decrease in the concns. of chlorinated
orgs., both in the mill discharge and in the lake. Most wood extractives
also decreased in the effluent. However, the discharge of some wood
extractives, such as sitosterol, was not significantly affected by the
changes.
184. Method for producing chlorine dioxide using methanol and hydrogen
peroxide as reducing agents.
Nonni, Arthur J.; Graff, Robert J.; Liu, Raymond; Voss, Jerry N.;
Hammond, Timothy R.; Pan, George Y.; Renard, Jean J. (International
Paper Co.; Nonni, Arthur J.; Graff, Robert J.; Liu, Raymond; Voss,
Jerry N.; Hammond, Timothy R.; Pan, George Y.; Renard, Jean J.,
USA). PCT Int. Appl. WO 9813295 A1 2 Apr 1998, 24 pp.
DESIGNATED STATES: W: AL, AM, AT, AU, AZ, BA, BB, BG, BR,
BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GE, HU, ID, IL, IS,
JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK,
MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ,
TM, TR, TT, UA, UG, US, UZ, VN, YU, ZW, AM, AZ, BY, KG, KZ, MD,
RU, TJ, TM; RW: AT, BE, BF, BJ, CF, CG, CH, CI, CM, DE, DK, ES,
FI, FR, GA, GB, GR, IE, IT, LU, MC, ML, MR, NE, NL, PT, SE, SN, TD,
TG. (English). (World Intellectual Property Organization). CODEN:
PIXXD2. CLASS: ICM: C01B011-02. APPLICATION: WO
97-US17758 29 Sep 1997. PRIORITY: US 96-720088 27 Sep 1996.
DOCUMENT TYPE: Patent CA Section: 49 (Industrial Inorganic
Chemicals)
A method is described for producing chlorine dioxide by reacting alkali
metal chlorate with methanol and hydrogen peroxide in an aq. acidic
medium. Combining these reducing agents causes an unexpected
enhancement in chlorine dioxide generation.
185. Reduction of chlorine dioxide emissions from a Mathieson generator.
Shaw, R. (UBC, Vancouver, BC, Can.). Pulp Pap. Can., 99(3), 52-55
(English) 1998 Southam Inc. CODEN: PPCAAA. ISSN: 0316-4004.
DOCUMENT TYPE: Journal CA Section: 43 (Cellulose, Lignin, Paper,
and Other Wood Products)
A study of pulp bleaching ClO2 emissions from the ClO2 generator at
Crestbrook Forest Industries was performed to det. whether changes
would be necessary to meet the emission restriction. Gas samples
were analyzed to det. and evaluate possible solns. to ensure
compliance. Operation of the generator was discovered to have a
significant effect on final ClO2 emissions. The final solns. were
evaluated based on ensuring compliance as well as minimizing capital
cost.
186. Elemental chlorine-free (ECF) bleaching: balancing the effects of
hydrogen peroxide bleaching with pulp yield.
Ulrich Suess, Hans; Leporini Filho, Cesar (Degussa AG, Hanau D
63403, Germany). Congr. Anu. Celul. Pap., 30th, 15-28. Associacao
Brasileira Tecnica de Celulose e Papel: Sao Paulo, Brazil.
(Portuguese) 1997. CODEN: 65VZAJ. DOCUMENT TYPE:
Conference CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood
Products)
The effects of process temp. in bleaching of pulps with hydrogen
peroxide were evaluated in terms of delignification, consumption of
NaOH, effluent COD loads, pulp viscosity, and pulp yield. Optimum
delignification was attained at high temps., however pulp yields were
lower. The use of hydrogen peroxide allows for costs savings in ECF
processes, based on partial replacement of ClO2. Yield losses during
bleaching can be estd. based on effluent COD values.
187. Ozone in elemental chlorine-free (ECF) bleaching of kraft pulp.
Rodrigues Da Silva, Marcelo; Campos De Brito, Ana; Colodette, Jorge
Luiz (Universidade Federal Vicosa, Vicosa, Brazil). Congr. Anu. Celul.
Pap., 30th, 1-14. Associacao Brasileira Tecnica de Celulose e Papel:
Sao Paulo, Brazil. (Portuguese) 1997. CODEN: 65VZAJ.
DOCUMENT TYPE: Conference CA Section: 43 (Cellulose, Lignin,
Paper, and Other Wood Products)
The efficiency of ozone in ECF bleaching of kraft pulps was evaluated
in sequences QEop(ZE)DED, DEop(ZE)D, ZEopDED, (ZE)DEopD,
(DZ)EopDED, and (ZD)EopDED. The results are analyzed in terms of
ozone consumption to reach 90 * 0.5 % ISO brightness, bleaching
costs (reagent and steam), chlorine dioxide savings, mech. strength of
pulps, and selectivity and efficiency of ozone stages. A higher ozone
efficiency was achieved when ozone was applied in the later stages of
the bleaching process. Max. savings of chlorine dioxide were achieved
by the sequences QEop(ZE)DED and DEop(ZE)D and which were 60
and 55%, resp., lower in relation to the ref. The sequence DEop(ZE)D
presented the lowest operating costs and the sequence
OEop(ZE)DED the highest.
188. Powders providing controlled-sustained release of a microbicidal gas.
Barenberg, Sumner A.; Gray, Peter N.; Lelah, Michael (Bernard
Technologies, Inc., USA). PCT Int. Appl. WO 9811776 A1 26 Mar
1998, 56 pp. DESIGNATED STATES: W: AU, JP, SG; RW: AT, BE,
CH, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE.
(English). (World Intellectual Property Organization). CODEN: PIXXD2.
CLASS: ICM: A01N025-08. ICS: C01B011-02. APPLICATION: WO
97-US14172 29 Aug 1997. PRIORITY: US 96-26273 18 Sep 1996.
DOCUMENT TYPE: Patent CA Section: 5 (Agrochemical
Bioregulators)
A powder for sustained release of a microbicidal gas, such as ClO2,
includes a core contg. a mol. sieve, and a layer contg. an
acid-releasing agent on an outer surface of the core. The core and the
layer are free of water, and the core is capable of generating and
releasing a gas after hydrolyis of the acid releasing agent. Clinoptilolite
core particles were impregnated with Na chlorite and admixed with an
acid-releasing propylene glycol monostearate wax (prepn. given) to
give a powder releasing ClO2 upon exposure to moisture.
189. Evidence for the reaction of highly vibrationally excited ClO radicals
with nitrogen.
Delmdahl, Ralph F.; Gericke, Karl-Heinz (Hans-Sommer-Str. 10, Institut
fur Physikalische und Theoretische Chemie, Technische Universitat
Braunschweig, Braunschweig D-38106, Germany). Chem. Phys. Lett.,
281(4,5,6), 407-412 (English) 1997 Elsevier Science B.V. CODEN:
CHPLBC. ISSN: 0009-2614. DOCUMENT TYPE: Journal CA
Section: 74 (Radiation Chemistry, Photochemistry, and Photographic
and Other Reprographic Processes) Section cross-reference(s): 65,
73, 78
The stratospheric trace gas Cl dioxide dild. in N at normal pressure is
irradiated with laser light at a wavelength of 308 nm, which corresponds
essentially to the (X2B10,0,0) (A2A218,0,0) sym. stretch progression of
OClO. This highly vibrationally excited initial OClO state produces
ClO(X2PW,v,J) radicals contg. almost the entire amt. of excess energy
in their internal degrees of freedom. The ClO fragments resulting from
this dissocn. process carry sufficient internal energy to exceed the
activation energy for the reaction with N. Accordingly, the reaction
ClO(v * 0)+N2 Cl+N2O could represent an addnl. source for nitrous
oxide and at. Cl in the stratosphere. The generation of N2O is exptl.
obsd. in a single-shot laser expt. where the N2O is detected by a gas
chromatograph. There is in fact a strong evidence for the prodn. of
nitrous oxide via the vibrationally mediated reaction of ClO radicals with
abundant N mols.
190. The photochemical reaction between chlorine and chlorine perchlorate
at 366 nm.
Lopez, M. I.; Croce, A. E.; Sicre, J. E. (1900, Argent.). J. Photochem.
Photobiol., A, 112(2,3), 97-102 (English) 1998 Elsevier Science S.A.
CODEN: JPPCEJ. ISSN: 1010-6030. DOCUMENT TYPE: Journal
CA Section: 74 (Radiation Chemistry, Photochemistry, and
Photographic and Other Reprographic Processes)
The photolysis of Cl2 in the presence of Cl2O4 at 366 nm in the gaseous
phase has been investigated at 303 K. The UV absorbance of the gas
mixt. has been recorded spectrophotometrically after each photolysis
interval to monitor the reactant Cl2O4 pressure and det. quant. the
chlorinated reaction products. A quantum yield for Cl2O4 consumption
of 2.0*0.2 has been detd. The main reaction products are Cl2O7, Cl2
and O2, accompanied by small quantities of Cl2O6 and OClO. A
mechanism involving ClO4 radicals formed in the Cl atom abstraction
from Cl2O4 by Cl is proposed.
191. Preparation of chlorine dioxide for water treatment.
Sun, Xiaoran; Xiao, Guoliang; Yang, Min (Huagong Xi )Department of
Chemical Engineering), Hebei University of Science and Technology,
Tangshan 063009, Peop. Rep. China). Gongye Shuichuli, 17(6), 9-10
(Chinese) 1997 Gongye Shuichuli Zazhishe. CODEN: GOSHFA.
ISSN: 1005-829X. DOCUMENT TYPE: Journal CA Section: 61
(Water) Section cross-reference(s): 49
High purity ClO2 (98-99%) was prepd. from NaClO3 with org. acid as
reductant. The effects of the absorption method of ClO2, reductant type
and content, and temp. on ClO2 yield were examd. Temp. played an
important role on ClO2 yield, and the operation was run at <100* to
prevent possible violent reaction. Stable ClO2 was also produced
using Na percarbonate as stabilizer.
192. Application of stable chlorine dioxide in circulating cooling water.
Cai, Juxiang; Wu, Kaiqi (Research Center, Zhenhai Refining and
Chemical Company Ltd., Ningbo 315207, Peop. Rep. China). Gongye
Shuichuli, 17(5), 8-10 (Chinese) 1997 Gongye Shuichuli Zazhishe.
CODEN: GOSHFA. ISSN: 1005-829X. DOCUMENT TYPE: Journal;
General Review CA Section: 61 (Water)
A review, with 7 refs., on the application of stable ClO2 in circulating
cooling water including the performance of stable ClO2 as bactericide
and its application in circulating cooling water.
193. Manufacture of aqueous chlorine dioxide and its apparatus for good
concentration stability.
Ogawa, Katsutoshi; Oyama,Masako (Chisso Corp., Japan). Jpn.
Kokai Tokkyo Koho JP 10081503 A2 31 Mar 1998 Heisei, 7 pp.
(Japanese). (Japan). CODEN: JKXXAF. CLASS: ICM: C01B011-02.
ICS: B01F001-00. APPLICATION: JP 96-253935 4 Sep 1996.
DOCUMENT TYPE: Patent CA Section: 49 (Industrial Inorganic
Chemicals)
Aq. mineral acid solns. and aq. chlorite solns. are introduced to column
reactors contg. static mixers, and generated 1.0-4.0% aq. ClO2 solns.
are dild. by water in connected mixing columns contg. static mixers to
give 10-3000 mg/L aq. ClO2 solns. App. for the above process is also
claimed.
194. Use of hydrated salts to enhance performance in the production of
chlorine dioxide from sodium chlorite and chlorine gas.
Battisti, Diana L.; Knapp, Joseph E. (Johnson & Johnson, USA). Eur.
Pat. Appl. EP 832845 A2 1 Apr 1998, 14 pp. DESIGNATED
STATES: R: AT, BE, CH, DE, DK, ES, FR, GB, GR, IT, LI, LU, NL, SE,
MC, PT, IE, FI. (English). (European Patent Organization). CODEN:
EPXXDW. CLASS: ICM: C01B011-02. APPLICATION: EP
97-307642 29 Sep 1997. PRIORITY: US 96-723070 30 Sep 1996.
DOCUMENT TYPE: Patent CA Section: 49 (Industrial Inorganic
Chemicals)
ClO2 gas is generated by contacting a feedstream of Cl2 gas with
NaClO2 and 1-30 wt.% of a hydrated inorg. salt contg. water of crystn.,
esp. Na2SO4.10H2O. The inorg. salt releases its water of hydration,
providing moisture to enhance prodn. of ClO2. The method increases
the amt. of ClO2 produced by a NaClO2 column, and increases the
generating lifetime of the column. The NaClO2 and hydrated inorg. salt
can be admixed in a single column, provided as sep. layers within a
single column, or provided in sep. columns.
195. Method for producing chlorine dioxide using methanol, chloride, and
hydrogen peroxide as reducing agents.
Nonni, Arthur J.; Graff, Robert J.; Liu, Raymond; Voss, Jerry N.;
Hammond, Timothy R. (International Paper Co.; Nonni, Arthur J.; Graff,
Robert J.; Liu, Raymond; Voss, Jerry N.; Hammond, Timothy R.,
USA). PCT Int. Appl. WO 9813296 A1 2 Apr 1998, 21 pp.
DESIGNATED STATES: W: AL, AM, AT, AU, AZ, BA, BB, BG, BR,
BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GE, GH, HU, ID, IL,
IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK,
MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ,
TM, TR, TT, UA, UG, US, UZ, VN, YU, ZW, AM, AZ, BY, KG, KZ, MD,
RU, TJ, TM; RW: AT, BE, BF, BJ, CF, CG, CH, CI, CM, DE, DK, ES,
FI, FR, GA, GB, GR, IE, IT, LU, MC, ML, MR, NE, NL, PT, SE, SN, TD,
TG. (English). (World Intellectual Property Organization). CODEN:
PIXXD2. CLASS: ICM: C01B011-02. APPLICATION: WO
97-US18156 29 Sep 1997. PRIORITY: US 96-720087 27 Sep 1996.
DOCUMENT TYPE: Patent CA Section: 49 (Industrial Inorganic
Chemicals) Section cross-reference(s): 43
ClO2 is produced by reacting an alkali metal chlorate (e.g., NaClO3)
with CH3OH, metal chloride (e.g., NaCl), and H2O2 (at <50%) as
reducing agents in an aq. acidic medium (e.g., H2SO4, HCl, H3PO4,
HNO3, HClO3) at 20-140癈, esp 50-75癈. A catalyst may be used,
selected from AgNO3, MnSO4, V2O5, Ru oxide, Rh oxide and PdO. The
reaction can be carried out at atm. pressure or sub-atm. pressure. The
combination of these reducing agents causes an unexpected
enhancement in ClO2 generation.
196. Treatment of wastewater or sludges of river, lake, and sea.
Ito, Kunio (Nippon Sangyo Kikaku K, K,, Japan). Jpn. Kokai Tokkyo
Koho JP 10057999 A2 3 Mar 1998 Heisei, 4 pp. (Japanese). (Japan).
CODEN: JKXXAF. CLASS: ICM: C02F011-14. ICS: C02F001-52;
C02F001-76; C02F011-06. APPLICATION: JP 96-241343 23 Aug
1996. DOCUMENT TYPE: Patent CA Section: 60 (Waste Treatment
and Disposal)
The process consists of contacting wastewater or sludges with 100
ppm or 10% ClO2 to decomp. matrixes comprising sand, (in)org.
substances, and microorganism, and removing the resulting sludges.
Alternatively, the process comprises treating with wastewater or
sludges with ClO2, and mixing the resulting materials with coagulants to
remove (in)org. substances decompd. The process is useful for
treatment of wastewater, dredging sludges, and wastewater treatment
sludges.
197. Method for producing chlorine dioxide using chemically impregnated
zeolite.
Klatte, Fred; Aamodt, James (Klatte Inc.; Environmental Safety
Systems, Inc., USA). U.S. US 5730948 A 24 Mar 1998, 9 pp.
Cont.-in-part of U.S. 5567405. (English). (United States of America).
CODEN: USXXAM. CLASS: ICM: C01B011-03. NCL: 423477000.
APPLICATION: US 96-704086 28 Aug 1996. PRIORITY: US
92-975680 13 Nov 1992; US 93-150438 10 Nov 1993; US 95-382601
2 Feb 1995; US 95-445025 19 May 1995. DOCUMENT TYPE: Patent
CA Section: 49 (Industrial Inorganic Chemicals)
Chlorine dioxide is manufd. by moving a fluid contg. oxygen through a
first bed of zeolite crystals impregnated with at least one of the
following: phosphoric acid, acetic acid and citric acid, and then moving
the fluid through a second bed of zeolite crystals impregnated with
sodium chlorite and/or zeolite crystals impregnated with chlorine.
Some of the produced chlorine dioxide is absorbed by moving the fluid
through a third bed of chem. impregnated zeolite crystals.
198. Simultaneous determination of chlorine dioxide and hypochlorite in
water by high-performance liquid chromatography.
Watanabe, Takaho; Idehara, Toshikazu; Yoshimura, Yoshihiro;
Nakazawa, Hiroyuki (Shinagawa-ku, Ebara, 2-4-41, Faculty of
Pharmaceutical Sciences, Department of Analytical Chemistry, HOSHI
University, Tokyo 142, Japan). J. Chromatogr., A, 796(2), 397-400
(English) 1998 Elsevier Science B.V. CODEN: JCRAEY. ISSN:
0021-9673. DOCUMENT TYPE: Journal CA Section: 61 (Water)
Section cross-reference(s): 79
The simultaneous detn. of ClO2 and hypochlorite by HPLC was
developed. The chromogenic substance formed by the
oxidn.-condensation reaction using 4-aminoantipyrine and phenol was
detd. at 503 nm by a post-column reaction system. ClO2 and
hypochlorite were sepd. within 3 min by the elution soln. (1.7-1.8mM Na
carbonate) at 0.5 mL/min into a lab.-prepd. PTFE tube column packed
with Waters Accell QMA as the anion-exchange material. A linear
correlation between the peak height and concn. was obtained within
1-20 mg/mL for ClO2 and 47-200 mg/mL for hypochlorite, with good
reproducibility (relative std. deviations of 4.0 and 2.2%, resp.,
replicated detn.). The limits of detection of ClO2 and hypochlorite were
approx. 0.2 and 10 mg/mL (S/N=3), resp.
199. Electrochemical process development at Olin based on advances in
electrodes, cell designs, and chemical feedstocks.
Kaczur, Jerry J.; Scott, Leonard L.; Dotson, Ronald L. (Chlor Alkali
Products Division, Olin Corporation, Charleston, TN 37310, USA).
Electrochem. Process. Technol., Int. Forum, Electrolysis Chem. Ind.,
11th, 213-245. Electrosynthesis: Lancaster, N. Y. (English) 1997.
CODEN: 65ORAS. DOCUMENT TYPE: Conference; General Review
CA Section: 72 (Electrochemistry)
A review with 40 refs.on the advances in new tech. development at Olin
made in developing electrochem. processes of sodium hydrosulfite,
hydroxylammonium nitrate (HAN), and chlorine dioxide prodn. is
presented. A novel two-compartment membrane cell design utilizing a
multilayer porous stainless steel fiber base cathode and bipolar
flow-through cell design are described. Anode material chosen for
HAN prodn. was a Pt clad niobium wire. It is shown that added salts in
sodium chlorite feed significantly improves current efficiency and
promote utilization of entire electrode length.
200. Method and apparatus for the purification of fluids.
Marchiori, Adriano; Innocente, Giuseppe; Mastel, Marco (Electrolux
Zanussi Grandi Impianti S.P.A., Italy). Eur. Pat. Appl. EP 823277 A2
11 Feb 1998, 10 pp. DESIGNATED STATES: R: AT, BE, CH, DE,
DK, ES, FR, GB, GR, IT, LI, LU, NL, SE, MC, PT, IE, SI, FI. (English).
(European Patent Organization). CODEN: EPXXDW. CLASS: ICM:
B01D050-00. ICS: F24C015-20. APPLICATION: EP 97-111902 12
Jul 1997. PRIORITY: IT 96-PN48 5 Aug 1996. DOCUMENT TYPE:
Patent CA Section: 60 (Waste Treatment and Disposal) Section
cross-reference(s): 17
Method and app. for the purifn. of fluids contg. contaminants and
pollutants, wherein solid particles are sepd. centrifugally from the fluid
being treated in a wet centrifuge, while deodorization of the same fluid
occurs through injection of chlorine dioxide in a countercurrent flow with
respect to the fluid by means of nozzles arranged in a mixing chamber .
In the preferred embodiment, the app. comprises two modules that
may be connected with each other in a no. of different configurations.
The system is esp. suitable for treatment of waste gases from food
cooking and prepn. operations.