Classifications

• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
  • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
  • D21C9/10—Bleaching ; Apparatus therefor
  • D21C9/16—Bleaching ; Apparatus therefor with per compounds
  • D21C9/163—Bleaching ; Apparatus therefor with per compounds with peroxides
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B15/00—Peroxides; Peroxyhydrates; Peroxyacids or salts thereof; Superoxides; Ozonides
  • C01B15/01—Hydrogen peroxide
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B15/00—Peroxides; Peroxyhydrates; Peroxyacids or salts thereof; Superoxides; Ozonides
  • C01B15/01—Hydrogen peroxide
  • C01B15/022—Preparation from organic compounds
  • C01B15/023—Preparation from organic compounds by the alkyl-anthraquinone process

Definitions

• the present invention relates to an installation for supplying hydrogen peroxide to a processing unit at an industrial site.
• the hydrogen peroxide used is always delivered to the treatment unit, in the form of a concentrated aqueous solution, for example from 50 to 70% by weight, by tank or by container.
• This method of supplying hydrogen peroxide has many drawbacks, in particular security problems linked to the numerous unloading operations for concentrated hydrogen peroxide solutions and the costs associated with transporting it and diluting it to the concentration d on the processing unit.
• the Applicant has envisaged the production of hydrogen peroxide in a slightly concentrated aqueous solution in the processing unit of the industrial site itself. However, most sites operate almost continuously throughout the year, frequently at least 360 days a year and do not allow the interruption of supply of hydrogen peroxide. Such an interruption is likely to occur, for example during maintenance operations of the installation of production of hydrogen peroxide.
• the invention aims to allow an uninterrupted supply of the hydrogen peroxide treatment unit, while allowing the usual maintenance operations of the supply installation.
• the subject of the invention is an installation for supplying hydrogen peroxide to a treatment unit of an industrial site, characterized in that it comprises a main installation for the production of hydrogen peroxide at a concentration of use, arranged on the site of the treatment unit, and an emergency installation , intended to supply the processing unit in the event of a shutdown of the main installation, comprising an emergency reserve of hydrogen peroxide at a storage concentration greater than the use concentration and means for diluting the stored hydrogen peroxide connected between the reserve and the treatment unit and making it possible to reduce the concentration of stored hydrogen peroxide up to the concentration of use.
• the emergency installation also comprises means for injecting a stabilizer into the diluted hydrogen peroxide;
• the use concentration of hydrogen peroxide is between 5 and 15% by weight;
• the concentration of hydrogen peroxide in reserve is between 50 and 70% by weight;
• the weight of the volume of hydrogen peroxide in reserve is between 100 and 200 tonnes;
• the main production installation is of the type implementing a process for the production of hydrogen peroxide with anthraquinone
• the processing unit is a unit for bleaching paper pulp in a paper production site.
• the invention will be better understood on reading the description which follows given solely by way of example for the understanding of which reference is made to the drawings, in which: - Figure 1 is a block diagram of a hydrogen peroxide feed installation according to the invention;
• FIG. 2 is a schematic view of a main installation for the production of hydrogen peroxide, integrated into the installation of Figure 1, according to a preferred embodiment.
• FIG. 1 shows an installation 10 for supplying hydrogen peroxide to a processing unit 12 of an industrial site.
• This processing unit 12 is for example a pulp bleaching unit from a paper production plant or site.
• the installation 10 comprises a main installation 14 for producing hydrogen peroxide arranged on the site of the treatment unit 12.
• the main installation 14 is intended to produce hydrogen peroxide at a relatively low use concentration preferably between 5 and 15% by weight.
• the installation 10 for supplying hydrogen peroxide also comprises an emergency installation 16 intended to supply the treatment unit 12 in the event of the main installation being stopped.
• the emergency installation 16 comprises a reserve of emergency hydrogen peroxide 18 and means 20 for diluting stored hydrogen peroxide of known type. These dilution means 20 are connected between the reserve 18 and the processing unit 12 via an upstream conduit 22 and a downstream conduit 24.
• the hydrogen peroxide stored in reserve 18 is of the type usually supplied on the market.
• the hydrogen peroxide in reserve has a concentration greater than the use concentration, preferably between 50 and 70% by weight, and a volume of which the weight is preferably between 100 and 200 tonnes, so as to be able to supply, for example, a conventional pulp bleaching unit for approximately one week.
• the main installation 14 is connected to the processing unit 12 via a conduit 26.
• conduit 24 downstream of the reserve 18 and the conduit 26 downstream of the installation 14 are connected to the same conduit 28 supplying the processing unit 12.
• Valves 30, 32 make it possible to isolate the main installation 14 and the emergency installation 18 respectively from the processing unit 12.
• the hydrogen peroxide at the desired use concentration is supplied directly to the treatment unit by the main production installation 14.
• this latter installation is connected to the production unit. treatment 12 by opening the valve 30 while the reserve 18 is isolated from the treatment unit 12 by closing the valve 32.
• the emergency installation 16 comprises means 34 for injecting into the diluted hydrogen peroxide a stabilizer of known type, chosen by example among the carboxylic, aminomethylene-carboxylic, phosphonic and aminomethylenephosphonic compounds, in particular ethylenediamine tetraacetic acid (EDTA) or its salts, diethylenetriamine-pentaacetic acid (DTPA) or its salts, polyacryli acids - ques, diethylenetriaminepentamethylenephosphonic acid or its salts, diamino-1,2NNN'N 'tetramethylenphosphonic acid or its salts, hydroxyethylbismethethylene phosphonic acid or its salts.
• EDTA ethylenediamine tetraacetic acid
• DTPA diethylenetriamine-pentaacetic acid
• polyacryli acids - ques diethylenetriaminepentamethylenephosphonic acid or its salts, diamino-1,2NNN'N 'tetramethylenphosphonic acid or its salts,
• the main installation 14 for producing hydrogen peroxide is preferably of the type implementing an anthraquinone process. An installation of this type is shown in Figure 2.
• the production installation 14 in FIG. 2 comprises three main devices in the form of columns: a catalytic hydrogenator 101, a counter-current oxidizer 102, and a water extractor 103. It also includes numerous equipment associated with these three devices , only some of which have been represented: a booster-condenser assembly 104 for recirculating the gaseous mixture containing hydrogen, associated with the hydro ⁇ generator; a filter 106, a pump 107, a heat exchanger 108, a water cooler 109, a head condenser 110 and an air compressor 111 associated with 1 * oxy ⁇ deur; a pipe 112, as short as possible, connecting the base of the oxidizer 102 to that of the extractor 103; and a coalescer 114 and a pump 115 for recycling the working solution.
• a booster-condenser assembly 104 for recirculating the gaseous mixture containing hydrogen, associated with the hydro ⁇ generator
• FIG. 2 also shows a line 116 for supplying the hydrogenator with make-up hydrogen, a line 117 for supplying air to the compressor 111, a line 118 for supplying the extractor 103 with demineralized water, a pipe 119 for producing hydrogen peroxide, which leaves from the base of the extractor 103 and ends at the treatment unit 12 consuming hydrogen peroxide at the same concentration, and a pipe 121 for recycling the working solution.
• Line 119 is connected to line 26.
• the hydrogen peroxide production installation includes many other pieces of equipment well known in the art and not shown, such as means for regenerating degraded products of the working solution, for using the catalyst, for recovering solvent, etc.
• the working solution consisting of at least one anthraquinone derivative and at least one organic solvent
• a stream of hydrogen-containing gas is also introduced at the base of the hydrogenator.
• This gas stream consists on the one hand of the gas stream drawn off at the top of the hydrogenerator, recirculated by the booster-condenser assembly 104, and on the other hand of make-up hydrogen arriving via line 116 .
• the working solution is thus partially reduced.
• the reduced solution drawn off from the base of the hydrogenator by the pump 107 via the filter 106, therefore contains hydroquinone derivatives (for example 80% tetrahydroanthrahydroquinone and 20% anthrahydroquinone).
• the anthraquinonine derivative constituting the working solution is preferably chosen from the 2 alkyl 9.10 anthraquinones in which the alkyl substituent comprises from 1 to 5 carbon atoms, such as the methyl, ethyl, sec-butyl, tert-butyl radicals , tertio-amyl, as well as the corresponding tetrahydro-5,6,7,8 derivatives, or among the dialkyl 9,10 anthraquinones in which the identical or different alkyl substituents comprise from 1 to 5 carbon atoms, such as methyl radicals , ethyl, tertiobutyl, for example 1.3 dimethyl, 1.4 dimethyl, 2.3 dimethyl, 2.7 dimethyl, 1.3 diethyl, 2.7 ditertiobutyl, 2 ethyl 6 tertiobutyl and the tetrahydro-5,6 derivatives, 7.8 corresponding.
• the alkyl substituent comprises from 1
• the organic solvent constituting the working solution is preferably a mixture of a non-polar compound and a polar compound.
• the non-polar compound is preferably chosen from petroleum fractions with a boiling point above 140 ° C. containing predominantly aromatic hydrocarbons containing at least 9 carbon atoms, such as the isomers of trimethylbenzene, the isomers of tetramethylbenzene , tert-butylbenzene, the isomers of methylnaphthalene, the isoers of dimethylnaphthalene.
• the polar compound is preferably chosen from saturated alcohols preferably containing from 7 to 11 carbon atoms, such as diisobutylcarbinol, 3,5,5-trimethyl hexanol, isoheptanol, esters of carboxylic acids such as as methyl cyclohexyl acetate sold under the name of "Sextate", heptyl acetate, butyl benzoate, ethyl heptanoate, esters of phosphoric acid such as tributyl phosphate , tri (2 ethyl butyl) phosphate, tri (2 ethyl hexyl) phosphate, tri (n-octyl) phosphate, tetrasubstituted ureas such as tetra (n-butyl urea).
• saturated alcohols preferably containing from 7 to 11 carbon atoms, such as diisobutylcarbinol, 3,5,5-trimethyl hexan
• hydrogen peroxide equivalent is understood below to mean the quantity of hydrogen peroxide, expressed in grams, that a liter of working solution is capable of supplying at the end of the oxidization step. tion if the yield of this step in the oxidizer 102 is 100%.
• This potential mass concentration of peroxide corresponds to a molar concentration which is equal to the molar concentration of all the rehydratable anthrahydroquinone forms in the working solution. It depends on the one hand on the concentration in anthraquinone forms of the starting working solution, and on the other hand on the hydrogenation conditions at 101.
• the hydrogenation is carried out at a temperature of between 50 and 70 ° C., with a pressure in the gaseous sky of the hydrogenator (pressure which regulates the flow of hydrogen) from 0.8 to 1.5 bar approximately, and the hydrogen peroxide equivalent is adjusted to a value of between 7 and 9 g / 1 approximately, by adjusting the residence time in the hydrogenator, for a given concentration in anthraquinone forms.
• the reduced working solution withdrawn from the hydrogenator is filtered at 106 to remove all traces of catalyst, then cooled at 108 and then at 109 to a temperature of the order of 35 to 40 "C.
• the pressure of the gaseous sky of the oxidizer is maintained at a value of between 2 and 4 bars.
• the reduced working solution is thus oxidized at 102, the head fluid of the oxidizer being partially condensed at 110.
• the hydrogen peroxide formed by the oxidation reaction is withdrawn from the base of the oxidizer, in an amount equal to the product of the hydrogen peroxide equivalent mentioned above by the yield of the oxidizer, as a mixture. with the oxidized working solution again.
• This liquid is sent directly via line 112, thanks to the difference in driving pressure at the base of the extractor 103, which operates a little above atmospheric pressure.
• the extractor is carried out a liquid-liquid extraction by means of demineralized water introduced at the top of the extractor.
• a water-hydrogen peroxide solution is drawn from the base of the latter, the hydrogen peroxide concentration of which is adjusted to the value necessary for its direct use in the treatment unit 12.
• the working solution separated from the hydrogen peroxide is withdrawn from the top of the extractor 103, freed from the droplets of aqueous phase which it has entrained in the coalescer 114, then sent by the pump 115 to the heat exchanger 108, in which it heats up, and, from there, recycled to the base of the hydrogé ⁇ nator 101.
• the oxidizer 102 comprises an outer casing containing an organized lining, or simple resfo trays or trays of the type distillation trays, that is to say each with a liquid guard, bubbling orifices for gas rising through this guard, and means for lowering liquid from one tray to the next, or a combination of 'an organized packing and such trays.
• the invention has many advantages.
• the installation according to the invention enables a hydrogen peroxide treatment unit to be supplied without interruption, while allowing maintenance operations to be carried out on the installation.
• the emergency installation supplies the processing unit in place of the main installation.
• the dimensions of the reserve 18 are relatively small given the high concentration of hydrogen peroxide stored therein.
• the installation according to the invention overcomes the drawbacks due to the supply of hydrogen peroxide, in the form of a concentrated aqueous solution, in particular the risks associated with unloading operations.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Wood Science & Technology (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Paper (AREA)
• Oxygen, Ozone, And Oxides In General (AREA)
• Apparatus For Disinfection Or Sterilisation (AREA)
• Storage Of Fruits Or Vegetables (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=9476581

Family Applications (1)

Country Status (12)

Family Cites Families (2)

• 1995
  • 1995-02-28 FR FR9502319A patent/FR2730984B1/fr not_active Expired - Fee Related
• 1996
  • 1996-02-14 WO PCT/FR1996/000244 patent/WO1996026897A1/fr not_active Application Discontinuation
  • 1996-02-14 CA CA002214049A patent/CA2214049A1/en not_active Abandoned
  • 1996-02-14 EP EP96904142A patent/EP0812298A1/fr not_active Withdrawn
  • 1996-02-14 AU AU48349/96A patent/AU4834996A/en not_active Abandoned
  • 1996-02-14 BR BR9607432A patent/BR9607432A/pt active Search and Examination
  • 1996-02-14 JP JP8526053A patent/JPH11500996A/ja active Pending
  • 1996-02-14 CN CN96192215.XA patent/CN1176629A/zh active Pending
  • 1996-02-27 MY MYPI96000702A patent/MY132346A/en unknown
  • 1996-02-27 CO CO96009194A patent/CO4560352A1/es unknown
  • 1996-04-01 TW TW085103797A patent/TW302410B/zh active
• 1997
  • 1997-08-27 FI FI973511A patent/FI973511A/fi unknown

Non-Patent Citations (1)

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