Source: http://www.google.com/patents/US5441603?dq=6004266
Timestamp: 2016-05-03 09:55:32
Document Index: 508511769

Matched Legal Cases: ['art 2', 'art 2', 'art 2', 'art 2', 'art 1', 'art 1']

Patent US5441603 - Method for chelation of pulp prior to ozone delignification - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsA process for delignifying and bleaching a lignocellulosic pulp without the use of elemental chlorine by partially delignifying the pulp to a K No. of about 10 or less and a viscosity of greater than about 13 cps; and further delignifying the partially delignified pulp with an effective amount of ozone...http://www.google.com/patents/US5441603?utm_source=gb-gplus-sharePatent US5441603 - Method for chelation of pulp prior to ozone delignificationAdvanced Patent SearchPublication numberUS5441603 APublication typeGrantApplication numberUS 08/097,699Publication dateAug 15, 1995Filing dateJul 27, 1993Priority dateMay 17, 1990Fee statusLapsedPublication number08097699, 097699, US 5441603 A, US 5441603A, US-A-5441603, US5441603 A, US5441603AInventorsBruce F. Griggs, Thomas P. Gandek, Michael A. Pikulin, Allen RosenOriginal AssigneeUnion Camp Patent Holding, Inc.Export CitationBiBTeX, EndNote, RefManPatent Citations (67), Non-Patent Citations (106), Referenced by (11), Classifications (9), Legal Events (4) External Links: USPTO, USPTO Assignment, EspacenetMethod for chelation of pulp prior to ozone delignification
US 5441603 AAbstract
1. A process for the manufacture of a bleached pulp having a certain GE brightness and a certain strength as indicated by a certain viscosity which comprises:chemically digesting a lignocellulosic material to initially form a pulp; oxygen delignifying the pulp to remove a substantial portion of the lignin therefrom, with the combination of the digesting and oxygen delignifying steps being conducted to form an intermediate pulp having a specified amount of lignin and a specified viscosity; treating the pulp at a pH of about 1 to 4 with a chelating agent to complex metal ions in the pulp and render such ions substantially non-reactive to ozone; and bleaching the treated pulp with a gaseous mixture that contains ozone by adjusting the consistency of the pulp to a high consistency of above about 28%, adjusting the pH of the pulp to below about 4, and treating the pulp with an amount of the ozone containing gaseous mixture sufficient to remove a substantial portion, but not all, of the lignin of the pulp by intimately contacting and turbulently mixing the pulp particles with the gaseous mixture in a dynamic reaction zone by introducing the high consistency pulp into the reaction zone to fill the zone to at least about 10% by volume, dispersing the pulp substantially completely throughout the reaction zone while simultaneously conveying the pulp therethrough in a plug flow-like manner at a dispersion index of about 7 or less thus exposing substantially all of the pulp to the ozone for reaction therewith for a sufficient time and at a temperature sufficient to allow access of the ozone to substantially all of the pulp for reaction therewith while the pulp advances through substantially all of the reaction zone, thus obtaining substantially uniform delignification of a significant portion of the pulp and forming a delignified pulp having a reduced amount of lignin and a certain strength, viscosity and GE brightness; wherein the specified amount of lignin of the intermediate pulp is such that, after ozone delignification, the delignified pulp attains the certain GE brightness, and wherein the specified viscosity of the intermediate pulp is sufficiently high to permit the delignified pulp, after ozone delignification, to attain the certain strength as evidenced by the certain viscosity. 2. The process of claim 1 which further comprises selecting the chelating agent to be a polycarboxylic acid, a polycarboxylate or a derivative thereof.
3. The process of claim 1 which further comprises selecting the chelating agent to be DPTA, EDTA or oxalic acid.
4. The process of claim 1 which further comprises bleaching the ozone delignified pulp with a peroxide.
5. The process of claim 1 which further comprises bleaching the treated pulp with ozone at a pH of between about 1 and 4.
6. The process of claim 1 which further comprises forming the pulp by Kraft pulping, Kraft-AQ pulping or extended delignification of a lignocellulosic material.
7. The process of claim 6 wherein the pulp is delignified with oxygen in a high consistency oxygen delignification step prior to treatment of the pulp with the chelating agent.
8. The process of claim 7 which further comprises conducting the oxygen delignification step by reducing the consistency of the pulp, substantially uniformly combining the reduced consistency pulp with an alkaline material, increasing the consistency of the pulp.
9. The process of claim 8 which comprises further bleaching the ozone delignified pulp to increase the brightness thereof.
10. The process of claim 9 wherein the ozone delignified pulp is treated with alkaline material prior to the further bleaching step.
11. The process of claim 10 wherein the pulp is treated with alkaline material to solubilize a portion of the lignin which remains in the pulp and which further comprises extracting a portion of the solubilized lignin to thus remove it from the pulp.
12. The process of claim 11 which further comprises comminuting the pulp particles prior to the ozone bleaching step.
13. A process for delignifying and bleaching a cellulosic material which comprises:chemically digesting a lignocellulosic material to initially form a pulp; oxygen delignifying the pulp to remove a substantial portion of the lignin therefrom, with the combination of the digesting and oxygen delignifying steps being conducted to form an intermediate pulp having a K No. of about 10 and a viscosity of at least about 13 cps; treating the pulp at a pH of about 1 to 4 with a chelating agent to complex metal ions in the pulp and render such ions substantially non-reactive to ozone; ozone delignifying the intermediate pulp with a gaseous mixtures that contains ozone by adjusting the consistency of the pulp to a high consistency of above about 28%, forming discrete pulp particles of a size having a sufficiently small diameter to facilitate substantially complete penetration of a majority of the particles by ozone gas, and treating the pulp with an amount of the ozone containing gaseous mixture sufficient to remove a substantial portion, but not all, of the remaining lignin by intimately contacting and turbulently mixing the pulp particles with the gaseous mixture in a dynamic reaction zone for a sufficient time and at a temperature sufficient to allow access of the ozone to substantially all of the pulp for reaction therewith while the pulp advances through substantially all of the reaction zone, thus obtaining substantially uniform delignification of a significant portion of the pulp and forming a delignified pulp having a K No. of about 5 or less, a viscosity of greater than about 10 cps, and a substantially uniform GE brightness of at least about 50%; treating the ozone delignified pulp with alkaline material to solubilize a portion of the lignin which remains in the pulp and extracting a portion of the solubilized lignin to form a substantially lignin-free pulp; and increasing the GE brightness of the substantially lignin-free pulp to at least about 70% by subjecting the pulp to a bleaching step. 14. The process of claim 13 wherein the GE brightness of the substantially lignin-free pulp is increased to at least about 80% by bleaching with chlorine dioxide or a peroxide compound.
15. The process of claim 13 which further comprises selecting the chelating agent to be a polycarboxylic acid, a polycarboxylate or a derivative thereof.
16. The process of claim 13 which further comprises selecting the chelating agent to be DPTA, EDTA or oxalic acid.
17. The process of claim 13 wherein the bleaching step includes bleaching the pulp with a peroxide.
18. The process of claim 13 which further comprises delignifying the treated pulp with ozone at a pH of between about 1 and 4.
19. The process of claim 13, which further comprises forming the pulp by Kraft pulping, Kraft-AQ pulping or extended delignification of a lignocellulosic material.
20. The process of claim 19 wherein the pulp is delignified with oxygen in a high consistency oxygen delignification step prior to treatment of the pulp with the chelating agent.
21. The process of claim 20 which further comprises conducting the oxygen delignification step by reducing the consistency of the pulp, substantially uniformly combining the reduced consistency pulp with an alkaline material, increasing the consistency of the pulp and treating the increased consistency pulp with oxygen under conditions effective to promote delignification thereof.
22. The process of claim 21 which further comprises increasing the consistency of the pulp prior to ozone delignification.
This application is a continuation of application Ser. No. 07/896,481 filed Jun. 2, 1992, which is a continuation of application Ser. No. 07/525,808 filed May 2, 1990, abandoned.
______________________________________C =   Chlorination            Reaction with elemental chlorine in acidic            medium.E =   Alkaline   Dissolution of reaction products with Extraction NaOH.Eo = Oxidative  Dissolution of reaction products with Alkaline   NaOH and Oxygen. ExtractionD =   Chlorine   Reaction with ClO2 in acidic medium. DioxideP =   Peroxide   Reaction with peroxides in alkaline            medium.O =   Oxygen     Reaction with elemental oxygen in            alkaline medium.Om = Modified   Uniform alkali treatment of low to Oxygen     medium consistency pulp followed by            reaction of high consistency pulp with            oxygen.Z =   Ozone      Reaction with ozone.Zm = Modified   Uniform reaction with ozone. OzoneC/D              Admixtures of chlorine and chlorine            dioxide.H =   Hypochlorite            Reaction with hypochlorite in an            alkaline solution.______________________________________
Other non-chlorine bleach sequences are described by S. Rothenberg, D. Robinson & D. Johnsonbaugh, "Bleaching of Oxygen Pulps with Ozone", Tappi 182-185 (1975)--Z, ZEZ, ZP and ZPa (Pa -peroxyacetic acid); and N. Soteland, "Bleaching of Chemical Pulps With Oxygen and Ozone", Pulp and Paper Magazine of Canada; T153-58 (1974)--OZEP, OP and ZP.
This homogeneous distribution step thus preferably comprises uniformly combining the pulp with an aqueous alkaline solution for at least about i minute and preferably no more than about 15 minutes. It is believed that treatment times of less than about 1 minute will not generally provide sufficient time to attain substantially uniform distribution, whereas treatment times in excess of about 15 minutes are not expected to produce substantial further benefit.
By use of the present invention, the ozone consumption may be reduced by using a number of alternate routes, such as standard kraft cooking followed by a modified oxygen delignification step (Om), or modified kraft pulping with extended delignification (such as Kamyr MCC, Baloit RDH or Sunds Cold Blow) followed by a conventional oxygen delignification step (O), or by Kraft AQ cooking followed by a conventional oxygen delignification step (O) as discussed above. An even greater reduction in ozone consumption will be achieved both with the use of modified Kraft pulping with extended delignification (Kamyr MCC, Beloit RDH or Sunds Cold Blow) followed by a modified oxygen delignification step (Om), or alternately when a Kraft AQ cooking process with extended delignification (Kamyr MCC, Beloit RDH or Sunds Cold Blow) is followed by a conventional oxygen delignification step (O). Using all of these techniques together in one process, i.e., Kraft AQ cooking modified by extended delignification (Kamyr MCC, Beloit RDH or Sunds Cold Blow), followed by a modified oxygen delignification step (Om), reduces the amount of ozone consumed even further. Reduction in the amount of ozone consumed generally permits the viscosity of the pulp to be maintained at acceptable levels.
The washed pulp 88 from the ozone stage is then combined with a sufficient amount of alkaline material 90 in extraction vessel 92 to effect extraction. Thus, pulp 88 is subjected to an aqueous alkaline solution for a predetermined time and at a predetermined temperature correlated to the quantity of alkaline material to solubilize a substantial portion of any lignin which remains in the pulp, in vessel 92. This extraction-process also increases the brightness of the pulp, typically by about 2 GE brightness points. Thereafter, the alkali treated pulp 94 is directed to washing unit 96, the aqueous alkaline solution is washed from the pulp so as to remove substantially all of the solubilized lignin from the pulp, thus forming a substantially lignin-free pulp. This step is well known to those skilled in the art and no further comment is deemed necessary here. The examples illustrate the preferred extraction parameters for this step of the process. At least a portion of the alkaline solution 98 which is recovered is recycled to washing unit 84. Again, major environmental benefits are achieved from the elimination of sewering of this solution.
In an effort to reduce the water demand of the process, it is-desirable to recycle as much of the effluent as possible. This practice cannot be used with processes utilizing chlorine or multiple steps of chlorine dioxide, since the effluents produced by these processes contain large amounts of chlorides produced by the by-products of such chemicals. Thus, recycling these effluents causes a build-up of chlorides which, in turn, causes either corrosion of processing equipment or the use of expensive materials of construction. In addition, such recycled effluents require substantial treatment before these effluents can be discharged from the mill, thus requiring further expenditures for equipment and treatment chemicals.
TABLE II______________________________________PINE TYPICAL CONVENTIONAL O STAGE BLEACHINGCONDITIONS                             PULPPRESSURE %                  TEMP  CONSISTENCY(PSIG)   CHEMICAL   pH      (�C.)                             (%)______________________________________80       2.5 NaOH   10.2    110   27*    0.1 MgSO4______________________________________ *both for alkali addition and oxygen delignification
TABLE III______________________________________PINE TYPICAL C/DED BLEACHING CONDITIONS                             PULP  CHEMICAL            TEMP   CONSISTENCYSTEP   (%)         pH      (�C.)                             (%)______________________________________C/D    3.6 Cl2              1.8     50        3.15  0.6 ClO2E      1.5 NaOH    11.6    70     12D      0.3 ClO2              4.2     60     12______________________________________
TABLE IV______________________________________PINE TYPICAL ACIDIFICATION CONDITIONS                             PULP    %                  TEMP  CONSISTENCYSTEP     CHEMICAL   pH      (�C.)                             (%)______________________________________Acidification    to pH 2    2       22    3-4(H2 SO4)Chelation    0.11       2       22    3-4(oxalic acid)______________________________________
TABLE V______________________________________PINE TYPICAL Zm ED BLEACHING CONDITIONS                             PULP   CHEMICAL           TEMP.  CONSISTENCYSTEP    (%)        pH      (�C.)                             (%)______________________________________Z (Ozone)   0.2 to 1   2 to 4   22    35-45E       1.5 NaOH   11.5     70    12D       1.0 ClO2               4.2     60    12______________________________________
TABLE VI______________________________________PINE KRAFT OC/DED AND KRAFT OZm EDPROPERTIES COMPARISONOC/DED           OZm ED TEAR     BREAK-                  BREAK- FAC-     ING             TEAR    INGCSF*  TOR      LENGTH    CSF*  FACTOR  LENGTH______________________________________646   205      6.54      659   228     5.85508   142      8.46      492   147     8.49351   145      8.81      334   126     8.50178   129      8.43      197   121     8.54______________________________________ *Canadian Standard Freeness
TABLE VII______________________________________PINE KRAFT OZm ED BRIGHTNESS RESPONSEClO2 (%)   0      1.3    1.5  1.7   1.9  2.2  2.5  2.8______________________________________Brightness   48.0   61.3   76.1 79.4  81.0 81.8 83.9 83.9(GEB %)______________________________________
TABLE IX______________________________________PINE KRAFT/AQ OC/DED AND OZm EDPROPERTIES COMPARISONOC/DED           OZm ED TEAR     BREAK-                  BREAK- FAC-     ING             TEAR    INGCSF   TOR      LENGTH    CSF   FACTOR  LENGTH______________________________________658   194      6.02      650   194     6.29524   139      8.14      497   159     7.83352   128      8.92      334   130     8.34190   119      8.74      211   121     8.59______________________________________
TABLE X______________________________________PINE KRAFT/AQ OZm ED BRIGHTNESS RESPONSEClO2 (%)        0      0.8    1.2   1.6  2.0  2.4______________________________________Brightness (GEB %)        52.9   76.8   80.7  83.2 83.4 83.8______________________________________
TABLE XI______________________________________COMPARISON OF OXYGEN STAGEBLEACHING RESULTS ON PULPSPRODUCED BY EXAMPLES 3 AND 4      EXAMPLE 3 (O)                 EXAMPLE 4 (Om)______________________________________K No.        13           9Viscosity (cps)        14.8         14.0______________________________________
Pulp produced from pine in accordance with the Om process of Example 4 of the present invention is compared to that produced conventionally (O) (i.e., with no low consistency alkaline treatment step). The average caustic dosage for high consistency oxygen delignification of brownstock pulp was found to be 45 pounds per oven dried ton (lb/t) or 2.3%. At that level, the average reduction in K No. across the oxygen delignification reactor was 10 units. For the same level of caustic applied to pulp according to a preferred treatment step, an average K No. drop during delignification was found to be 13 units: a 30% improvement compared to the conventional process.
TABLE XII______________________________________PINE KRAFT PULP PROPERTY COMPARISON         Conventional                   Modified         Oxygen    Oxygen         Treatment (O)                   Treatment (Om)______________________________________Unbleached PulpK No.           21.9        20.5Viscosity (cps) 21.5        20.5Ratio of K No./Viscosity            1.02        1.0Oxygen Delignification StagePulpK No.           12.1         8.3Viscosity (cps) 14.4        14.0Ratio of K No./Viscosity            0.84        0.59Caustic, lb/t   39.4        46.0Delignification (%)           44.7        59.5______________________________________
TABLE XIII______________________________________TYPICAL MODIFIED OXYGEN (Om)STAGE CONDITIONS   % CHEMICAL                PULP   USED ON OLD         TEMP  CONSISTENCYSTEP    FIBERS       pH     (�C.)                             (%)______________________________________Treatment   30%          --      22   3-4(NaOH)Oxygen(O2)   80 psig      10.2   110   27(MgSO4)   0.1______________________________________
TABLE XIV______________________________________PINE KRAFT C/DED BLEACHING CONDITIONS                             PULP  CHEMICAL           TEMP.   CONSISTENCYSTEP   (%)        pH      (�C.)                             (%)______________________________________C/D    2.4 Cl2             1.8     50         3.15  0.4 ClO2E      1.05 NaOH  11.5    70      12D      0.23 ClO2             4.2     60      12______________________________________
TABLE XVI______________________________________PINE Om C/DED and Om Zm ED PROPERTIESCOMPARISONOm C/DED    Om Zm ED          BREAK-                  BREAK-TEAR      ING             TEAR    INGCSF  FACTOR    LENGTH    CSF   FACTOR  LENGTH______________________________________656  147       6.80      659   177     5.57511  113       8.00      510   146     6.93335   96       8.69      367   111     7.90217  101       8.69      178   100     8.20______________________________________
TABLE XVII______________________________________Pine Om Zm ED BRIGHTNESS RESPONSEClO2 (%)  0           0.5    1.0______________________________________Brightness (GEB %)          55.0        70.0   84.2______________________________________
TABLE XVIII______________________________________HARDWOOD TYPICAL C/DED BLEACHINGCONDITIONS                             PULP  CHEMICAL           TEMP.   CONSISTENCYSTEP   (%)        pH      (�C.)                             (%)______________________________________C/D    1.61 Cl2             1.8     50         3.15  0.26 ClO2E      1.0 NaOH   11.9    70      12D      0.35 ClO2             4.2     60      12______________________________________
TABLE XX______________________________________ED TYPICAL BLEACHING CONDITIONS USED ON OZmHARDWOOD PULP  CHEMICAL            TEMP.  PULPSTEP   (%)        pH       (�C.)                             CONSISTENCY______________________________________E      1.0 NaOH   12.0     70     12D      0.35 ClO2             4.36     60     12______________________________________
TABLE XXI______________________________________HARDWOOD OC/DED AND OZm ED PROPERTIESCOMPARISONOC/DED           OZm ED          BREAK-                  BREAK-TEAR      ING             TEAR    INGCSF  FACTOR    LENGTH    CSF   FACTOR  LENGTH______________________________________526  89.9      4.41      515   88.3    4.52399  87.2      5.71      419   82.0    5.65262  79.5      6.26      293   70.5    6.56208  72.0      6.46      187   64.3    6.87______________________________________
TABLE XXII______________________________________HARDWOOD OZm ED BRIGHTNESS RESPONSEClO2 (%)       0      0.35______________________________________Brightness (GEB %)  64.0   84.4______________________________________
Delignification selectivity can also be expressed in terms of the change in viscosity versus the change in K No. between brownstock and the corresponding modified oxygen treated pulps. In comparing pulps which are conventionally oxygen treated with those of the invention, there is a greater decrease in delignification selectivity for increased degrees of delignification. For a change in K No. of 4 units, the average change in viscosity was 4 cps for pulps produced by the conventional process. By contrast, the change in K No. for the same change in viscosity for pulps produced by the modified oxygen method was 7 units. Expressed in terms. of a delignification selectivity ratio, the selectivity for the modified method was 1.8 K No./cps and that for the conventional process was 1 K No./cps, an increase of 80%. Results are shown in Table XXIII.
TABLE XXIII______________________________________PULP PROPERTY COMPARISON(HARDWOOD)        Conventional                  Modified        Oxygen    Oxygen        Treatment (O)                  Treatment (Om)______________________________________Unbleached PulpK No.          12.3        13.0Viscosity (cps)          21.6        23.4Ratio of K No./           0.57        0.56ViscosityOxygen Delignification Stage PulpK No.           7.6         6.0Viscosity (cps)          16.0        17.7Ratio of K No./           0.47        0.33ViscosityCaustic, lb/t  27.6        26.4Delignification (%)          38.0        54.0______________________________________
TABLE XXV______________________________________EFFECT OF pH ON HARDWOODSPARAMETER    pH 5     pH 4     pH 3   pH 2______________________________________CHANGE IN K NO.        -2.79    -3.17    -3.16  -3.67ACROSS THE ZmSTAGECHANGE IN    +12.1    +15.0    +11.7  +17.4BRIGHTNESSACROSS THE ZmSTAGE (GEB)CHANGE IN    -6.0     -7.1     -4.9   -4.4VISCOSITYACROSS THE ZmSTAGE (cps)______________________________________
TABLE XXVI______________________________________PINE CEDED BLEACHING CONDITIONS                             PULP  CHEMICAL            TEMP.  CONSISTENCYSTEP   (%)        pH       (�C.)                             (%)______________________________________C      5.3 Cl2              4.10    40        3.15E      3.25 NaOH  11.3     70     12D      1 ClO2             3        60     12E      0.6 NaOH   11.6     70     12D      0.12 ClO2             3        60     12______________________________________
TABLE XXVII______________________________________COMPARISON OF CEDED, OC/DED AND OZm EDBLEACHINGPARAMETER   CEDED      OC/DED    OZm ED______________________________________BOD5 (lbs/ton)       34         21        1Color (lbs/ton)       367        83        less than 1TOCl (lbs/ton)        7          4        0.8______________________________________
TABLE XXIX______________________________________ADDITIVE EFFECTS OF KRAFT/AQ AND MODIFIEDOXYGEN (Om) PINE PULPS          KRAFT + O  KRAFT/   KRAFT/PARAMETER      (Prior Art)                     AQ + O   AQ + Om______________________________________OZONE APPLICATIONOF 0.5% TO EACHCASEK No.          6.2        3.4       1.8VISCOSITY (cps)          12.1       11       10.1PROPERTIES ANDOZONE APPLICATIONAT TARGET K No.of 3.5Ozone (%)      1.0        0.5       0.29VISCOSITY (cps)          8.9        11       11.8______________________________________
TABLE XXX__________________________________________________________________________OZM ED BLEACHING CONDITIONS    CHEMICAL  TEMP.              TIME                  PULP  GEB                           K NO.                               VISCOSITY*STEP    (%)    pH (�C.)              (min.)                  CON. (%)                        (%)                           (40 ml)                               (cps.)__________________________________________________________________________Om    [Conditions given in Table XIII]                        40 8.5 12.5Zm0.43  2  22      1.5                  43    50 --  10E   1.5    11.5         70    60 12    -- --  9.8D   0.5    4 to 5         70   180 12    65 --  9.6    0.7                      70     9.6__________________________________________________________________________ *Viscosity values after the Om stage are interpolated values based o established data.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS1591070 *Feb 27, 1925Jul 6, 1926Wolf Robert BBleaching apparatusUS3318657 *Sep 23, 1963May 9, 1967Metal Hydrides IncMethod of bleaching cellulose fibresUS3451888 *Apr 28, 1966Jun 24, 1969ProgilBleaching pulp having high consistency with ozone having moisture content near 100%US3652388 *Dec 5, 1969Mar 28, 1972Mo Och Domsjoe AbBleaching and delignification of partially delignified pulp with a mixture of chlorine and chlorine dioxideUS3660225 *Jul 10, 1969May 2, 1972Air LiquideDelignification and bleaching of cellulose pulp layers with oxygen gasUS3663357 *Mar 18, 1970May 16, 1972Pulp Paper Res InstBleaching of mechanical cellulosic pulp with ozone in the presence of a peroxygen compoundUS3703435 *May 14, 1971Nov 21, 1972Sunds AbMethod for finely disintegrating pulp,preferentially cellulose pulp,in connection with the bleaching thereof with gaseous bleaching agentUS3725193 *May 27, 1970Apr 3, 1973Pulp Paper Res InstProcess and apparatus for the chemical reaction between a gas and a wood pulpUS3759783 *Aug 23, 1971Sep 18, 1973Domsjo AbProcess for bleaching cellulose pulp with alkali and oxygen gas utilizing waste bleaching liquor from an alka line oxygen gas bleaching stageUS3785577 *Jul 18, 1972Jan 15, 1974Improved Machinery IncApparatus for the gaseous reaction of materialUS3814664 *Sep 11, 1972Jun 4, 1974Improved Machinery IncGaseous reaction apparatus including a peripheral gas receiving chamberUS3832273 *May 15, 1972Aug 27, 1974Carborundum CoComposite refractory articlesUS3874992 *Sep 20, 1973Apr 1, 1975Pulp Paper Res InstPress alkaline extraction of cellulosic pulpUS3888727 *Apr 8, 1974Jun 10, 1975Canadian IndTreatment of lignocellulosic material in an alkaline pulping liquor containing anthraquinone sulphonic acid followed by oxygen delignificationUS3926798 *Oct 17, 1974Dec 16, 1975Us InteriorReverse osmosis membraneUS3964962 *Feb 25, 1974Jun 22, 1976Ingersoll-Rand CompanyGaseous reaction apparatus and processes including a peripheral gas receiving chamber and a gas recirculation conduitUS4046621 *Oct 28, 1975Sep 6, 1977The Ontario Paper Company LimitedProcess for treating a slurry of cellulosic materialUS4080249 *Jul 16, 1976Mar 21, 1978International Paper CompanyDelignification and bleaching of a lignocellulosic pulp slurry with ozoneUS4089737 *Aug 30, 1976May 16, 1978Toyo Pulp Company, Ltd.Delignification of cellulosic material with an alkaline aqueous medium containing oxygen dissolved thereinUS4119486 *Dec 2, 1976Oct 10, 1978Westvaco CorporationProcess for bleaching wood pulp with ozone in the presence of a cationic surfactantUS4123317 *Oct 29, 1976Oct 31, 1978Myrens Verksted A/SMethod and an apparatus for processing finely divided fibrous pulp with gas without overpressureUS4155806 *May 6, 1975May 22, 1979Skogsagarnas Industri AktiebolagMethod for continuous alkaline delignification of lignocellulose material in two or more steps, the final of which with oxygenUS4155845 *May 10, 1977May 22, 1979Rhone-Poulenc IndustriesTreatment of pulp mill effluentsUS4198266 *Oct 12, 1977Apr 15, 1980Airco, Inc.Oxygen delignification of wood pulpUS4216054 *Sep 26, 1977Aug 5, 1980Weyerhaeuser CompanyLow-consistency ozone delignificationUS4220498 *Dec 14, 1978Sep 2, 1980Kamyr, Inc.Oxygen reactor systems pulp reject treatmentUS4226673 *Mar 15, 1976Oct 7, 1980Champion International CorporationColor removal from paper and pulp mill aqueous effluentsUS4229252 *Jan 11, 1979Oct 21, 1980Weyerhaeuser CompanyAdditives for ozone bleachingUS4268350 *Sep 18, 1979May 19, 1981Eka AktiebolagMethod of treating pulp bleaching effluentsUS4274913 *May 22, 1979Jun 23, 1981Toyo Pulp Co., Ltd.Process for producing alkali pulpUS4278496 *Jul 13, 1979Jul 14, 1981Myrens Verksted A/SMethod for bleaching pulp with ozoneUS4283251 *Jan 24, 1980Aug 11, 1981Scott Paper CompanyOzone effluent bleachingUS4295925 *Jun 15, 1979Oct 20, 1981Weyerhaeuser CompanyTreating pulp with oxygenUS4295926 *Jun 15, 1979Oct 20, 1981Weyerhaeuser CompanyMethod and apparatus for treating pulp with oxygenUS4298427 *Jun 15, 1979Nov 3, 1981Weyerhaeuser CompanyMethod and apparatus for intimately mixing oxygen and pulp while using an alkali to extract bleaching by-productsUS4363697 *Dec 3, 1979Dec 14, 1982The Black Clawson CompanyMethod for medium consistency oxygen delignification of pulpUS4372812 *Feb 11, 1981Feb 8, 1983International Paper CompanyChlorine free process for bleaching lignocellulosic pulpUS4384920 *Aug 11, 1982May 24, 1983The Black Clawson CompanyMethod and apparatus for oxygen delignificationUS4431480 *Oct 27, 1981Feb 14, 1984The Black Clawson CompanyMethod and apparatus for controlled addition of alkaline chemicals to an oxygen delignification reactionUS4435249 *Nov 25, 1981Mar 6, 1984The Black Clawson Co.Process for the oxygen delignification of pulp mill rejectsUS4439271 *Jun 4, 1981Mar 27, 1984Mo Och Domsjo AktiebolagProcess for the oxygen bleaching of cellulose pulpUS4444621 *Dec 3, 1981Apr 24, 1984Mo Och Domsjo AktiebolagProcess and apparatus for the deresination and brightness improvement of cellulose pulpUS4450044 *Jul 19, 1982May 22, 1984Myrens Verksted A/SMethod for bleaching oxygen delignified cellulose-containing pulp with ozone and peroxideUS4451332 *Jul 29, 1982May 29, 1984Sca Development AktiebolagMethod for delignification of ligno-cellulose containing fiber material with an alkali-oxygen extraction stageUS4459174 *Jul 21, 1982Jul 10, 1984Interbox (Societe Anonyme)Process for the delignification and bleaching of chemical and semi-chemical cellulosic pulpsUS4468286 *Oct 13, 1983Aug 28, 1984Myrens Verksted A/SMethod of gas treatment of fluffed pulpUS4563243 *Jun 25, 1984Jan 7, 1986Hermann Berstorff Maschinenbau GmbhApparatus and a method for producing wood pulp in a hollow cylinder containing a rotatable screwUS4568420 *Dec 3, 1984Feb 4, 1986International Paper CompanyMulti-stage bleaching process including an enhanced oxidative extraction stageUS4595455 *Sep 4, 1981Jun 17, 1986Mannbro Systems HandelsbolagMethod for controlling batch alkaline pulp digestion in combination with continuous alkaline oxygen delignificationUS4640782 *Mar 13, 1985Feb 3, 1987Ozo-Tek, Inc.Method and apparatus for the generation and utilization of ozone and singlet oxygenUS4806203 *Feb 12, 1986Feb 21, 1989Elton Edward FMethod for alkaline delignification of lignocellulosic fibrous material at a consistency which is raised during reactionUS4840703 *Jun 29, 1988Jun 20, 1989Rauma-Repola OyMethod for controlling an oxygen bleachingUS5085734 *Mar 2, 1990Feb 4, 1992Union Camp Patent Holding, Inc.Methods of high consistency oxygen delignification using a low consistency alkali pretreatmentUS5164043 *Aug 26, 1991Nov 17, 1992Union Camp Patent Holding, Inc.Environmentally improved process for bleaching lignocellulosic materials with ozoneUS5174861 *Aug 28, 1991Dec 29, 1992Union Camp Patent Holdings, Inc.Method of bleaching high consistency pulp with ozoneCA966604A *Nov 22, 1971Apr 29, 1975Scott Paper CoKraft pulp bleaching and recovery processCA970111A *Nov 9, 1971Jul 1, 1975Scott Paper CoPreparation of wood pulpCA1103409A *Jun 26, 1978Jun 23, 1981Japan Pulp & Paper Res IncMethod of bleaching chemical pulp in multiple stagesCA1112813A *Jan 18, 1979Nov 24, 1981Int Paper CoMethod for extracting ozone-treated fibrous materialsCA1119360A *Apr 3, 1979Mar 9, 1982Myrens Verksted AsMethod for bleaching oxygen delignified cellulose-containing pulp with ozoneCA1154205A *Mar 11, 1981Sep 27, 1983Int Paper CoBrightness improvement of ozone bleached pulpsCA1181204A *May 21, 1982Jan 22, 1985Ingersoll Rand CoMethod and system for reacting ozone with pulpCA1186105A *Jun 17, 1983Apr 30, 1985Scott Paper CoOzone bleaching of cellulosic materialsEP0308314A1 *Sep 12, 1988Mar 22, 1989"DEGREMONT" Soci�t� dite:Process for the ozone treatment of lignocellulosic materials, in particular paper pulps, and reactor for carrying out this processFR2620744A1 * Title not availableWO1988003095A1 *Oct 26, 1987May 5, 1988The Yokohama Rubber Co., Ltd.Pneumatic radial tireWO1991018145A1 *May 17, 1990Nov 28, 1991Union Camp CorporationEnvironmentally improved process for bleaching lignocellulosic materials* Cited by examinerNon-Patent CitationsReference1Abrahanson and Samuelson, "Oxygen/Sodium Carbonate Bleaching of Kraft Pulp Pretreated with Nitrogen Dioxide and Oxygen", Svensk Papperstidning (1983).2 *Abrahanson and Samuelson, Oxygen/Sodium Carbonate Bleaching of Kraft Pulp Pretreated with Nitrogen Dioxide and Oxygen , Svensk Papperstidning (1983).3 *Allison, Effects of Temperature and Chemical Pretretment on Pulp Bleaching with Ozone, 1985 Int l Pulping Conference pp. 47 53.4Allison, Effects of Temperature and Chemical Pretretment on Pulp Bleaching with Ozone, 1985 Int'l Pulping Conference pp. 47-53.5 *Allison, Production of Bleached Softwood Pulp by Low Pollution Processes, Wood Sci. Technol. 17, pp. 129 137 (1983).6Allison, Production of Bleached Softwood Pulp by Low Pollution Processes, Wood Sci. Technol. 17, pp. 129-137 (1983).7Andtbacka, "Low Kappa Pulping Followed by Oxygen Delignification", Appita, vol. 39, No. 2, (1986).8 *Andtbacka, Low Kappa Pulping Followed by Oxygen Delignification , Appita, vol. 39, No. 2, (1986).9Article, "Naco Straw Pulp", PPI, (Apr. 1987).10 *Article, Naco Straw Pulp , PPI, (Apr. 1987).11Balousck, "The Effects of Ozone Upon Lignin Model Containing the P-aryl Ether Linkage", Svensk Papperstidning, No. 9, 1981.12 *Balousck, The Effects of Ozone Upon Lignin Model Containing the P aryl Ether Linkage , Svensk Papperstidning, No. 9, 1981.13Brannland and Fossin, "How to Cope With TOCL", International Oxygen Delignification Conference, (1987).14 *Brannland and Fossin, How to Cope With TOCL , International Oxygen Delignification Conference, (1987).15Britt, "Pulp and Paper Technology".16 *Britt, Pulp and Paper Technology .17DeSousa et al., "The Influence of Chlorine Ratio and Oxygen Bleaching on the Formation of PCDF's and PCCD's in Pulp Bleaching", Tappi Journal (Apr. 1989).18 *DeSousa et al., The Influence of Chlorine Ratio and Oxygen Bleaching on the Formation of PCDF s and PCCD s in Pulp Bleaching , Tappi Journal (Apr. 1989).19Dow Chemical Co., "Keys to Chelation" (1985).20 *Dow Chemical Co., Keys to Chelation (1985).21Eickeler, "Ozone Measurement with Detector Tubes".22 *Eickeler, Ozone Measurement with Detector Tubes .23Eriksson and Gierer, "Ozonation of Residual Lignin".24 *Eriksson and Gierer, Ozonation of Residual Lignin .25Fossum et al., "Final Bleaching of Kraft Pulps Delignified to Low Kappa Number by Oxygen Bleaching", Tappi Journal pp. 60-62 (Dec. 1983).26 *Fossum et al., Final Bleaching of Kraft Pulps Delignified to Low Kappa Number by Oxygen Bleaching , Tappi Journal pp. 60 62 (Dec. 1983).27Gangolli, "The Use of Ozone and Pulp in the Paper Industry".28 *Gangolli, The Use of Ozone and Pulp in the Paper Industry .29Geiger, "Mechanisms of Bleach with Oxygen-Containing Species", ISWPC, (1987).30 *Geiger, Mechanisms of Bleach with Oxygen Containing Species , ISWPC, (1987).31Germgard and Sjogren, "Ozone Prebleaching of a Modified-Cooked and Oxygen-Bleached Softwood Kraft Pulp", Svensk Papperstidning, No. 15, (1985).32 *Germgard and Sjogren, Ozone Prebleaching of a Modified Cooked and Oxygen Bleached Softwood Kraft Pulp , Svensk Papperstidning, No. 15, (1985).33Germgard et al., "Mathematical Models for Simulation and Control of Bleaching Stages", Nordic Pulp and Paper Research Journal, No. 1 (1987).34 *Germgard et al., Mathematical Models for Simulation and Control of Bleaching Stages , Nordic Pulp and Paper Research Journal, No. 1 (1987).35Germgard, "Chlorate Discharge from Bleach Plants--How to Handle a Potential Environmental Problem", Paperi ja Puu, V. 71, No. 3, (1989).36 *Germgard, Chlorate Discharge from Bleach Plants How to Handle a Potential Environmental Problem , Paperi ja Puu, V. 71, No. 3, (1989).37Gierer, "Chemistry of Delignification, Part 2: Reactions of Lignins During Bleaching", Word Science and Technology (1986).38 *Gierer, Chemistry of Delignification, Part 2: Reactions of Lignins During Bleaching , Word Science and Technology (1986).39Godsay and Pearce, "Physico-Chemical Properties of Ozone Oxidized Kraft Pulps", Oxygen Delignification (1984).40 *Godsay and Pearce, Physico Chemical Properties of Ozone Oxidized Kraft Pulps , Oxygen Delignification (1984).41Gregor and Gregor, "Synthetic-Membrane Technology", Scientific American, (Jul. 1970).42 *Gregor and Gregor, Synthetic Membrane Technology , Scientific American, (Jul. 1970).43 *Gupta, et al., OZ Prebleaching, Influence on Viscosity and Sheet Strength, TAPPI Symposium Oxygen Delignification, p. 1 (1984).44Gupta, et al., OZ Prebleaching, Influence on Viscosity and Sheet Strength, TAPPI Symposium--Oxygen Delignification, p. 1 (1984).45 *Heimburger et al., Kraft Mill Bleach Plant Effluents: Recent Developments Aimed at Decreasing Their Environmental Impact.46 *Heimburger et al., Kraft Mill Bleach Plant Effluents: Recent Developments Aimed at Decreasing Thier Environmental Impact Part II, TAPPI Journal, p. 69 (Nov. 1988).47Hill and Rice, "Handbook of Ozone Technology and Applications", Ann Arbor Science.48 *Hill and Rice, Handbook of Ozone Technology and Applications , Ann Arbor Science.49Jamieson and Smedman, "Integration of Oxygen Bleaching in the Brown Stock Washing System", Svensk Papperstidning (1973).50 *Jamieson and Smedman, Integration of Oxygen Bleaching in the Brown Stock Washing System , Svensk Papperstidning (1973).51Katai and Schuerch, "Mechanism of Ozone Attack on Alpha-Methyl Glucoside and Cellulosic Materials".52 *Katai and Schuerch, Mechanism of Ozone Attack on Alpha Methyl Glucoside and Cellulosic Materials .53 *Klein et al. Delignifying Bleaching of Sulfite Pulps With Hydrogen Peroxide, EUCEPA Conference Report (Jun. 1980).54 *Leibergott, et al., The Use of Ozone in Bleaching and Brightening Wood Pulps: Part I Chemical Pulps (TAPPI 1978).55Leibergott, et al., The Use of Ozone in Bleaching and Brightening Wood Pulps: Part I--Chemical Pulps (TAPPI 1978).56 *Liebergott, et al., Bleaching a Softwood Kraft Pulp Without Chlorine Compounds, pp. 1 10.57Liebergott, et al., Bleaching a Softwood Kraft Pulp Without Chlorine Compounds, pp. 1-10.58 *Liebergott, et al., Bleaching a Softwood Kraft Pulp Without Chlorine Compounds, TAPPI Journal, p. 76 (Aug. 1984).59Lindholm "Effect of Pulp Consistency and pH in Ozone Bleaching: Part 2", International Oxygen Delignification Conference (1987).60 *Lindholm Effect of Pulp Consistency and pH in Ozone Bleaching: Part 2 , International Oxygen Delignification Conference (1987).61Lindholm, "Effect of Heterogeneity in Pulp Bleaching with Ozone", Paperi ja Puu, (Apr. 1987).62Lindholm, "Effect of Pulp Consistency and pH in Ozone Bleaching", Paperi ja Puu, (Mar. 1987).63 *Lindholm, Effect of Heterogeneity in Pulp Bleaching with Ozone , Paperi ja Puu, (Apr. 1987).64 *Lindholm, Effect of Pulp Consistency and pH in Ozone Bleaching , Paperi ja Puu, (Mar. 1987).65McDonough, "Oxygen Bleaching's Pace Quickens", IPC Technical Paper Series, No. 246 (Jul. 1987).66 *McDonough, Oxygen Bleaching s Pace Quickens , IPC Technical Paper Series, No. 246 (Jul. 1987).67Norden and Simonson, "Ozone Bleaching of Sulphite Pulp--A Pilot Plant Study".68 *Norden and Simonson, Ozone Bleaching of Sulphite Pulp A Pilot Plant Study .69Ouederni, "Simulation of the Ozone/Lignin Reaction in an Agitated vessel".70 *Ouederni, Simulation of the Ozone/Lignin Reaction in an Agitated vessel .71 *Ow, et al., Advances In Ozone Bleaching: Part II: Bleaching of Softwood Kraft Pulps With Oxygen and Ozone Combination, TAPPI Symposium Oxygen Delignification (1984).72Ow, et al., Advances In Ozone Bleaching: Part II: Bleaching of Softwood Kraft Pulps With Oxygen and Ozone Combination, TAPPI Symposium--Oxygen Delignification (1984).73 *Patt, et al., Use of Ozone For Pulp Bleaching, Papier, 42 (10A), V 14 23 (1988).74Patt, et al., Use of Ozone For Pulp Bleaching, Papier, 42 (10A), V 14-23 (1988).75 *Perkins et al., Advances in Ozone Bleaching Part III Pilot Plant Installations and Proposed Commercial Implementation.76Perkins et al., Advances in Ozone Bleaching--Part III--Pilot Plant Installations and Proposed Commercial Implementation.77Reeve and Earl, "Chlorinated Organic Matter in Bleached Chemical Pulp Production Part 1: Environment Impact and Regulations of Effluents, Pulp and Paper Canada", 90:4, (1989).78 *Reeve and Earl, Chlorinated Organic Matter in Bleached Chemical Pulp Production Part 1: Environment Impact and Regulations of Effluents, Pulp and Paper Canada , 90:4, (1989).79 *Sarkanen, et al., Chlorination free Doxy Bleaching Process for Kraft Pulps.80Sarkanen, et al., Chlorination-free Doxy Bleaching Process for Kraft Pulps.81Schleinkofer, "Overview of A Chlorine-Free Bleaching Process", 1981 Oxidative Bleaching Conf.; Denver Oct. 22, 1981.82 *Schleinkofer, Overview of A Chlorine Free Bleaching Process , 1981 Oxidative Bleaching Conf.; Denver Oct. 22, 1981.83Schuerch, "Ozonization of Cellulose and Wood, Journal of Polymer Science", No. 2, (1963).84 *Schuerch, Ozonization of Cellulose and Wood, Journal of Polymer Science , No. 2, (1963).85Singh "The Bleaching of Pulp", Tappi Press, 3rd Edition.86 *Singh The Bleaching of Pulp , Tappi Press, 3rd Edition.87 *Singh, Advances in Ozone Bleaching Part I: The Ozone Bleaching Process Laboratory to Pilot Plant.88Singh, Advances in Ozone Bleaching--Part I: The Ozone Bleaching Process--Laboratory to Pilot Plant.89 *Singh, Ozone Replaces Chlorine in the First Bleaching Stage: Advances in Ozone Bleaching Part I, TAPPI Journal, p. 45 (Feb. 1982).90Singh, Ozone Replaces Chlorine in the First Bleaching Stage: Advances in Ozone Bleaching--Part I, TAPPI Journal, p. 45 (Feb. 1982).91 *Smith, The Sequestration of Metals, Macmillan, New York 1959 pp. 54 69.92Smith, The Sequestration of Metals, Macmillan, New York 1959 pp. 54-69.93Soteland, "Bleaching of Chem. Pulps with Oxygen & Ozone" Pulp & Paper of Canada, pp. 91-96 Apr. 1974.94 *Soteland, Bleaching of Chem. Pulps with Oxygen & Ozone Pulp & Paper of Canada, pp. 91 96 Apr. 1974.95 *Soteland, Bleaching of Chemical Pulps with Oxygen and Ozone, Pulp and Paper Magazine of Canada, vol. 75, No. 4, Apr. 1974 pp. 91 95.96Soteland, Bleaching of Chemical Pulps with Oxygen and Ozone, Pulp and Paper Magazine of Canada, vol. 75, No. 4, Apr. 1974 pp. 91-95.97 *Soteland, Comparison Between Oxygen and Ozone Delignification of Sulphite Pulps, TAPPI Symposium Oxygen Delignification p. 71 (1984).98Soteland, Comparison Between Oxygen and Ozone Delignification of Sulphite Pulps, TAPPI Symposium--Oxygen Delignification p. 71 (1984).99Talka and Priha, "Fractionation and Identification of Some Biologically Active Compounds in Bleached Kraft Mill Effluents", Paperi ja Puu (1987).100 *Talka and Priha, Fractionation and Identification of Some Biologically Active Compounds in Bleached Kraft Mill Effluents , Paperi ja Puu (1987).101Tritschler and Shelton, "Commercial Manufacture and Industrial Use of Ozone and an Oxidant".102 *Tritschler and Shelton, Commercial Manufacture and Industrial Use of Ozone and an Oxidant .103Vidal and Holinier, "Ozonolysis of Lignin--Improvement of In Vitro Digestibility of Poplar Sawdust", Biomass 16, (1988).104 *Vidal and Holinier, Ozonolysis of Lignin Improvement of In Vitro Digestibility of Poplar Sawdust , Biomass 16, (1988).105Voss et al., "Some New Insights Into the Origins of Dioxins Formed During Chemical Pulp Bleaching", Pulp and Paper Canada, 89:12 (1988).106 *Voss et al., Some New Insights Into the Origins of Dioxins Formed During Chemical Pulp Bleaching , Pulp and Paper Canada, 89:12 (1988).* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS6036726 *Feb 6, 1998Mar 14, 2000Solutia Inc.Process for separating polyamide from colorantUS6083283 *Feb 6, 1998Jul 4, 2000Solutia Inc.Method for removing color from ionically dyeable polymeric materialsUS7976676Dec 18, 2006Jul 12, 2011International Paper CompanyProcess of bleaching softwood pulps in a D1 or D2 stage in a presence of a weak baseUS7976677Dec 18, 2006Jul 12, 2011International Paper CompanyProcess of bleaching hardwood pulps in a D1 or D2 stage in a presence of a weak baseUS20080142174 *Dec 18, 2006Jun 19, 2008Caifang YinProcess in a (D) stage bleaching of softwood pulps in a presence of Mg (OH) 2US20080142175 *Dec 18, 2006Jun 19, 2008Caifang YinProcess in a (D) stage bleaching of hardwood pulps in a presence of Mg (OH)2WO2005024126A1 *Aug 6, 2004Mar 17, 2005International Paper CompanyChlorine dioxide delignification of medium consistency pulpWO2008076267A2 *Dec 12, 2007Jun 26, 2008International Paper CompanyA process in a (d) stage bleaching of softwood pulps in a presence of mg(oh)2WO2008076267A3 *Dec 12, 2007Aug 14, 2008Int Paper CoA process in a (d) stage bleaching of softwood pulps in a presence of mg(oh)2WO2014140940A3 *Mar 12, 2014Jan 8, 2015Gp Cellulose GmbhA low viscosity kraft fiber having an enhanced carboxyl content and methods of making and using the sameWO2015138335A1 *Mar 9, 2015Sep 17, 2015Gp Cellulose GmbhA low viscosity kraft fiber having an enhanced carboxyl content and methods of making and using the same* Cited by examinerClassifications U.S. Classification162/57, 162/56, 162/65International ClassificationD21C9/153, D21C9/10Cooperative ClassificationD21C9/153, D21C9/1057European ClassificationD21C9/153, D21C9/10GLegal EventsDateCodeEventDescriptionDec 12, 1995CCCertificate of correctionMar 9, 1999REMIMaintenance fee reminder mailedAug 15, 1999LAPSLapse for failure to pay maintenance feesOct 26, 1999FPExpired due to failure to pay maintenance feeEffective date: 19990815RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services