CN104169493A - A method and a system for treating liquid flows at a chemical pulp mill - Google Patents
A method and a system for treating liquid flows at a chemical pulp mill Download PDFInfo
- Publication number
- CN104169493A CN104169493A CN201380014049.6A CN201380014049A CN104169493A CN 104169493 A CN104169493 A CN 104169493A CN 201380014049 A CN201380014049 A CN 201380014049A CN 104169493 A CN104169493 A CN 104169493A
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- Prior art keywords
- water
- chlorine content
- low chlorine
- bleaching
- process water
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- 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
- D21C11/00—Regeneration of pulp liquors or effluent waste waters
- D21C11/0021—Introduction of various effluents, e.g. waste waters, into the pulping, recovery and regeneration cycle (closed-cycle)
-
- 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
- D21C11/00—Regeneration of pulp liquors or effluent waste waters
- D21C11/0014—Combination of various pulping processes with one or several recovery systems (cross-recovery)
-
- 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
- D21C11/00—Regeneration of pulp liquors or effluent waste waters
- D21C11/0021—Introduction of various effluents, e.g. waste waters, into the pulping, recovery and regeneration cycle (closed-cycle)
- D21C11/0028—Effluents derived from the washing or bleaching plants
-
- 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
- D21C11/00—Regeneration of pulp liquors or effluent waste waters
-
- 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
- D21C3/00—Pulping cellulose-containing materials
-
- 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
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- Paper (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
Abstract
The invention relates to a method for treating liquid flows at a chemical pulp mill. The system comprises a cooking process for producing pulp, at least one washing stage for washing the pulp, at least one bleaching stage for bleaching the pulp, a waste water treatment plant (40), a raw water treatment plant (30), and a wood processing unit (50), and the method comprises conveying at least a portion of low chloride content process waters to the chemical pulp mill in order to be reused as process water. In addition, the invention relates a system for treating liquid flows at a chemical pulp mill and a use of low chloride content process waters at a chemical pulp mill.
Description
Invention field
The present invention relates to a kind of method and system at chemical pulp mills treatment fluid stream.
Background technology
Conventionally in waste water disposal facility, process the effluent of chemical pulp mills, to reduce the amount of environmentally harmful chemicals.Exist many motivations to reduce the use of water and the volume of effluent, for example, supply the cost of former water, water supply that may be limited, saves energy, and reduces the possibility of fiber and chemicals loss.At present, pulp mill is based upon in the region and environment of very strict environmental requirement conventionally.The amount of the water for example, chemical pulp mills being used has strict restriction.Therefore, likely cannot set up pulp mill in the satisfactory place of other side due to water resource.In many cases, need more clean environment, the material that requires pulp mill to produce is less to the harm of environment.Therefore, importantly find at present a kind of scheme, to find to have more the water circulation method of closure.
Summary of the invention
The present invention discloses a kind of method and system at chemical pulp mills treatment fluid stream.According to the present invention, secondary water circulation is provided, it preferably includes low chlorine content process water or is made up of low chlorine content process water.
At present, conventionally processed together from whole effluent streams of chemical pulp mills.The invention provides a kind of scheme, reduce the total amount of pulp mill's effluent by the purest part of process water is separated and circulated.So just can re-use these process waters stream and without processing, therefore this scheme is cost-effective in waste water disposal facility.
The target of the preferred embodiment for the present invention is the secondary water circulation that produces low chlorine content independently, contributes to like this utilization of water, if the lighter purifying of desirability only can be purified this circulation with cost-effective purification process.
Preferably, this system comprises:
-for the digestion process of boiling paper pulp,
-at least one washing stage, to wash described paper pulp,
-at least one bleaching stage, to bleach described paper pulp,
-waste water disposal facility, and
-former water processing establishment.
In a preferred example, comprise according to system of the present invention:
-at least one timber processing apparatus,
-slightly starch preparation facilities, it comprises the boiling for the production of paper pulp, washing, screening and oxygen go the wooden stage,
-bleaching system, it comprises the paper pulp that bleaching stage is produced with bleaching, this bleaching system preferably includes Na Shi (Nash) pump seal water and/or bleaching filter liquor,
-chemical recovery device, it can comprise ejector condenser cooling water and/or vavuum pump sealing water,
-recovery boiler, it also produces boiler and discharges water, and
-evaporimeter, it produces condensate.
In addition, this system can comprise pulp dryer.But this system also can not comprise described pulp dryer.
Preferably, comprise the following steps according to method of the present invention:
-at least a portion low chlorine content process water is exported from pulp mill,
-this low chlorine content process water is recycled to pulp mill, as process water.
Preferably, at least a portion low chlorine content process water is transported to homogenization groove and/or pond, is then again used as the process water of pulp mill.
The chlorinity of low chlorine content process water is preferably less than 200mg/l, is more preferably less than 100mg/l.As a supplement or substitute, the Ca content of low chlorine content process water is preferably less than 200mg/l, is more preferably less than 100mg/l.Preferably, the pH of low chlorine content process water is 6.5-10.
Preferably, low chlorine content process water stream comprises the fiber process Wiring technology water from pipeline.As an alternative or supplement, low chlorine content process water stream preferably comprises the sealing water from black liquor vaporizing and recovery filtration zone.As an alternative or supplement, low chlorine content process water stream preferably comprises the sealing water from desalination facility.As an alternative or supplement, low chlorine content process water stream preferably comprises the discarded object (rejects) from drying machine.As an alternative or supplement, low chlorine content process water stream preferably comprises the groove overflow from drying machine.
Preferably, low chlorine content process water stream is at least in part as the washings in fire demand water pipeline and/or the sealing water in fire demand water pipeline.
One preferred embodiment in, low chlorine content process water stream is first purified, then just again as the process water of pulp mill.Preferably, by chemical method and/or mechanical means, low chlorine content process water stream is carried out to purifying.Preferably, low chlorine content process water stream first carries out purifying by least one in following technology, then just again as process water:
-chemical flocculation technology,
-clarification technique,
-sand filtration technology and
The combination of-two or three above-mentioned technology.
Preferably, in former water processing establishment, implement purifying.As an alternative or supplement, can implement described purifying by the purification devices that comprises machinery or chemical purification device.
The present invention can implement in the chemical pulp mills with following process or device: digestion process, at least one bleaching stage, chemical recovery, and various reactor well known by persons skilled in the art, container, pump, blender, filter etc.
Have benefited from the present invention, a kind of system with following ability can be provided:
-can reduce the ambient influnence of chemical pulp mills,
-can reduce the former water consumption of chemical pulp mills, and
-can reduce the amount of the effluent producing in pulp mill.
The feature of aspects more of the present invention is stated in independent claims 1,9 and 10.Various embodiment of the present invention is disclosed in dependent claims.
Brief description of the drawings
Hereinafter, the present invention is described by reference to the accompanying drawings in more detail, wherein:
Fig. 1-2 shows some illustrative embodiments with the schematic diagram of simplifying.
detailed Description Of The Invention
In this application, with reference to accompanying drawing 1-2, wherein use the following drawings mark:
10 low chlorine content process waters,
20 effluents that comprise bleaching effluent,
30 former water processing establishments,
40 waste water disposal facilities,
41 gravity tables,
50 wood treatment devices,
60 fire-fightings and sealing water, and
70 comprise at least one mechanical purification phase and/or the purification devices at least one chemical purification stage.This purification devices can comprise for example clarifier.
Term " low chlorine content process water " refers to have the process water of low chlorine content.Preferably, the chlorinity of low chlorine content process water is less than 200mg/l, is preferably less than 100mg/l.In addition, low chlorine content process water preferably has highly filled, and in addition, they preferably contain fiber.
Term " effluent " represents waste water.Effluent is transported to the waste water disposal facility for purge process.Effluent can comprise that for example bleaching effluent and ash leach purging thing (ash leaching purge). in addition, effluent can contain timber processing effluent.
Term " bleaching effluent " refers to the effluent from the bleaching system described in literary composition and washing step.Preferably, bleaching effluent contains bleaching filter liquor.More preferably, bleaching effluent forms by bleaching filter liquor.Bleaching filter liquor contains the acidity and/or the basic stream that in bleaching stage, produce.Preferably, not fibre-bearing of bleaching effluent.
Term " former water processing establishment " refers to fresh water treatment facility.
Term " effluent treatment facility " refers to waste water disposal facility.
Term " ECF " refers to not containing elemental chlorine.
Term " TCF " refers to completely not chloride.
Term " ESP " represents electrostatic precipitator.
Term " can recirculation water " refers to clean is enough to the process water as process water in technical process again.Can recirculation water can be in former water processing establishment 30 and/or at least one purification devices 70 purifying.
Term " EOP " refers to use the alkaline extraction stage in the pulp bleaching process that oxygen and peroxide carry out as extra chemical substance.
Term " NPE " refers to that non-process element (non-process elements) .NPE is from process equipment, and from the inorganic substances of timber, former water and chemical substance, they are not that procedure is needed yet sometimes.
Term " secondary water circulation " refers to comprise the process water circulation of the low chlorine content process water that is not transported to waste water disposal facility.
Term " Adt " represents the air dry metric ton number of 90% dry chemical paper pulp.
Fire demand water refers to by the water for washing various objects and in case of emergency supplying for the water supply line of putting out a fire.
Sealing water is the water for sealing in vavuum pump.
Ejector condenser cooling water is to be directed to the water that directly contacts with the steam in ejector condenser or owing to directly contacting the water of generation with steam.
Gravity table is the device for make sludge dewatering by wastewater treatment permeability band.Gravity table shower water is used for washing described band.
The general object of the boiling operation in the production of chemical pulp of bleaching is recycled fiber from be transported to the fragment digester, specifically utilizes chemicals and heating to remove the lignin of viscose fibre and removes below the wood extractive that bubbles in procedure causing and precipitation occurs.Therefore, in pulping process, normal use can be dissolved try one's best many lignin and as far as possible few cellulosic chemicals.Conventionally, the method for the chemical pulp of manufacture bleaching comprises slurrying, washing, screening, bleaching and cleaning stage.At present, sulfate boiling is the most frequently used method of manufcturing paper pulp, and also referred to as brown paper boiling or slurrying, it uses the mixture of NaOH (NaOH) and vulcanized sodium (Na2S).Method for cooking can be based on comprising a digester or several digesters boiling at intermittence or continuous cooking.
Thick slurry processing after boiling process preferably includes washing process, oxygen stage, and screening, washs subsequently.Conventionally, washing facility last in the oxygen stage is accepted the washing lotion that purity is the highest, and to promote association with pulp bleaching, the filtrate obtaining from this last washing facility is used as washing lotion dilution according to countercurrent washing principle.In the time reclaiming filtrate from the first thick plasm scouring equipment, filtrate can be delivered directly to forward to black liquor vaporizing equipment, or can in digester plant process for dilution with carry and changing, then finish with black liquor stream.After the in the end washing stage, bleaching process can lead paper pulp.
Improve brightness, cleannes and the brightness constancy of paper pulp with blanching step.Remaining lignin is the principal element that affects color, therefore must be removed or make it to brighten.Conventionally, the object of bleached pulp is to continue delignification, and utilize bleached chemical thing, remain in any wooden thing in paper pulp in boiling with after the oxygen stage to remove, it is residual lignin, these lignin can not decompose, and are dissolved in boiling and in the oxygen stage, and can not sacrifice paper output or fibre property.And, in bleaching process, remove chromogenic compound, and be oxidized to leuco-compounds.Conventionally, the pith of bleaching is on washer, the lignin of dissolving to be washed out from paper pulp after bleaching stage.
For the object of bleaching,
-can use chlorine (Cl
2), ozone (O
3) and/or peroxy acid (Paa and Caa) and the unit process of aromatics lignin, and/or
-conventionally can use chlorine dioxide (ClO
2) and/or oxygen (O
2) react with the lignin structure with free phenolic hydroxyl group, and/or
-can use hypochlorite (H) and/or hydrogen peroxide (H
2o
2) and some functional group reactionses.
But chemical pulp industry need to keep a kind of technology, wherein at least one stage, with chloride chemicals, paper pulp is bleached, making chlorine dioxide is the main chemicals that use in pulp mill's bleaching process.Therefore, advantageously to major general's chlorine dioxide (ClO
2) for bleaching object.
Bleaching effluent is an important source of biological and chemical oxygen consumption normally.For example, may be retained in procedure from chloride inorganic compound and the organochlorine compound of the reaction of chlorine dioxide and/or chlorine.Bleaching process separates various lignin compounds from fiber, and these compounds are retained in effluent with the form of organic molecule.In addition, in bleaching stage, can use sulfuric acid to carry out pH adjusting, and the main chemicals that are hydrolyzed as hexenuronic acid (hexenuronic acid).In alkali stage, can also use NaOH to carry out pH adjusting and lignin extraction.In addition,, according to bleaching order, in bleaching, can use oxygen and/or peroxide.But in elementary analysis, they should be the materials meeting the following conditions: they are negligible on the impact of for example purge process.
In an example, use hydrochloric acid to carry out pH adjusting, and/or use sulfur dioxide and/or other reductant to remove the chemical residue from bleaching process, remove unreacted bleached chemical thing.
Not only there is bleaching effluent in pulp mill, also has process water, for example cooling water, sealing water, slurry, rainwater and the timber process water of waste streams (reject flows), channel water, equipment.Described process water does not contact with pulping process conventionally, but timber process water and some derive from except the channel water of technique overflow, and they contact with pulping process.Therefore, the effluent of accumulation is mainly leakage and overflow therein, the equipment interim effluent causing that breaks, and the slurry of equipment, derives from continuously or fabric (silk screen and felt) or the container of intermittently washing, derives from the leakage of discarding system.
As mentioned above, thick slurry is processed and is comprised at least one washing process.Advantageously, thick slurry is processed and is comprised:
-screening process,
-oxygen goes the wooden stage, and
-at least one washing stage after oxygen goes the wooden stage.
Screening process can be positioned at after digester purges, in the middle of the washing process or afterwards, or after oxygen goes the wooden stage.Conventionally, after these process stages, be bleaching process, be preferably based on ECF technology, it comprises having one or more association with pulp bleaching facilities based on using the bleaching stage of chlorine dioxide and using the possible stage of other known bleached chemical thing.Advantageously, bleaching process comprises at least one alkali stage, wherein preferably at least uses oxygen and/or peroxide.Can also use ozone stage, acid phase and chelate stage for removing heavy metal.
At least comprise the alkaline boiling process for the production of paper pulp according to method of the present invention, preferably use the bleaching facility (wherein forming chloride effluent) of ECF bleaching, and the effluent purifying facility (waste water disposal facility) of other effluent producing for the treatment of bleaching facility effluent and/or in pulp mill.Or, can use TCF bleaching to replace ECF bleaching.
Advantageously use ECF bleaching, wherein said bleaching comprises acidic phase and alkali stage simultaneously.ECF bleaching comprises all such bleaching process, comprises at least one chlorine dioxide stage and in any bleaching stage, does not use element state chlorine.At present for the modern ECF bleaching process of bleached pulp conventionally by least two, more advantageously at least three bleaching stages form, described bleaching stage preferably includes at least three washing facilitys.If use chlorine dioxide in a bleaching stage, the most frequently used dosage is 5-15kg act.Cl/adt paper pulp.Chlorine dioxide dosages for cork is generally 25-35kg/adt, is generally 20-30kg/adt for the chlorine dioxide dosages of hardwood.If pulp mill also will further reduce the amount of organochlorine compound, the policy of pulp mill is normally processed it in pulp mill, instead of reduces the use of chlorine dioxide.
Pulp mill generally includes chemical recovery facility, and it comprises the evaporation process conventionally with the evaporation equipment being connected in series, and chemical recovery boilers is removed chloride from technical process, and for the production of the chemical production facility of boiling chemicals.
The circulatory system of at least part of closure for the preparation of the chemical pulp of bleaching is applicable to the method for wherein at least part of water and other chemicals recirculation and re-using, thereby farthest reduces refuse processing.Described system is specially adapted to farthest reduce aqueous effluent, and therefore protection of the environment is avoided being subject to the impact that effluent is disposed, and the value that can obviously not jeopardize process costs or salable item.Chlorine, potassium, calcium, manganese, silicon, aluminium, phosphorus, iron and barium are some elements that relate in the chemical pulp mills of bleaching.
Preferably, at least one effluent of waste water disposal facility is processed to line biological treatment is provided.In the time that the ratio of harmful organic substance declines, biological treatment is effective especially, and described harmful organic substance mainly comprises the lignin compound separating in bleaching, hemicellulose and the component that derives from extraction, the major part of the effluent of their formation bleaching facilities.Have many compounds that derive from timber, the part in these compounds is chlorination, and a part is low-molecular-weight hydrocarbon.Because microorganism is only using the organic moiety of effluent as nutrient, all inorganic substances, at least inorganic elements is retained in effluent.Therefore, through the water of biological treatment, after for example by sedimentation separation solid constituent and liquid component, from the organic component aspect containing, obviously cleaner than the effluent of otherwise processing, but because it contains inorganic substances, conventionally it must be discharged from technical process.
Fig. 1 shows an example of pulp mill.Conventionally,, in pulp mill, fragment and white liquid are supplied to the digester for paper pulp boiling.After boiling, the processing stage of being transported to washing and oxygen through the paper pulp (so-called thick slurry) of boiling.Conventionally, hot water is for the described washing stage.Light/dark balance liquid from boiling operation is transported to evaporation stage from boiling operation, in this stage, some water is removed from light/dark balance liquid, therefore produce aterrimus liquid.From the water of light/dark balance liquids recovery, i.e. self-evaporating condensate, is preferably delivered in washing stage or thick slurry.The aterrimus liquid producing at evaporation stage is processed, to obtain green liquor.Further process green liquor, to obtain being reused for the white liquid of boiling.The processing stage of from the washing of thick slurry and oxygen out, paper pulp is transported to bleaching system.Bleaching system generally includes the several bleaching stages for bleached pulp.Bleaching system produces acid and alkaline effluent conventionally in bleached pulp, and these effluents are transported to waste water disposal facility conventionally.Paper pulp through bleaching is transported to paper mill or pulp dryer conventionally.
Fig. 2 shows an example of secondary water circulation with the schematic diagram of simplifying.For example, this example can be implemented in the pulp mill according to Fig. 1.Fig. 2 shows low chlorine content process water stream 10, the effluent 20 that comprises bleaching effluent, former water processing establishment 30, waste water disposal facility 40, gravity table 41, wood treatment device 50, fire-fighting and sealing current 60, and optional purification devices 70.
Before at least one purification devices 70 can be positioned at former water processing establishment 30, and/or after being positioned at former water processing establishment 30.
Described former water processing establishment 30 preferably at least comprises that former water input and waterfall shape rush down, former water clarifier, sand filter and/or more medium filter.Preferably, former water processing establishment 30 comprise at least two, more preferably at least three, most preferably at least four independently process line.If low chlorine content process water stream 10 is processed in former water processing establishment 30, can be transported in any described purification phase of former water processing establishment 30.
Low chlorine content process water stream 10 can clean in the processing line that is different from the former water that comes from water system.In this case, low chlorine content process water stream 10 with independently purifying in the processing line of former water processing establishment 30 of former water.Or, low chlorine content process water stream 10 can with together with former water from water system 10 at least one of former water processing establishment 30 processed line purifying.But preferably, separate for processing line and the former water source of purifying low chlorine content process water stream 10 in former water processing establishment 30, this at least one processing line is preferably only for purifying low chlorine content process water stream 10.
According to the present invention, a part of process water is separated after the lighter purifying of degree and re-using preferably.Due to this secondary water circulation, circulate inner existence of process water.In other words, not all process water is all transported to waste water disposal facility 40, but a part of process water re-uses in this process.Have benefited from this secondary water circulation, can reduce the former water consumption of pulp mill.
Preferably, ash is processed to waste streams and merge with acidity and basic stream from bleaching, form effluent stream 20.If EOP filter liquor, for timber processing 50, is preferably delivered into from the liquid stream of timber processing apparatus 50 effluent stream 20 that comprises bleaching effluent.Otherwise, be preferably delivered into low chlorine content process water stream 10 from the liquid stream of timber processing apparatus 50.The effluent stream 20 that comprises bleaching effluent is preferably delivered into waste water disposal facility 40.
Preferably by fire-fighting and sealing water guiding low chlorine content process water stream 10.As a supplement or substitute, from being preferably directed to low chlorine content process water stream 10 comprising from the current of the water of pipeline of fiber process line.
Preferably, this system comprises purification devices 70, and it comprises at least one mechanical purification phase and/or at least one chemical purification stage for purifying low chlorine content process water stream 10.Preferably, purification devices 70 is the clarifiers for removing suspended solid.
If use purification devices 70, in machinery or chemical purification device 70, the water of purifying is preferably directed to former water processing establishment 30 at least in part.As an alternative or supplement, in machinery or chemical purification device 70, the water of purifying is preferably directed to pulp mill again as process water.But this process water must recirculation, if do not use former water processing establishment or any other purification devices after the processing of described purification unit, after purification devices 70, clean and be enough to as process water.
Preferably, at least a portion low chlorine content process water 10 is purifying in purification devices 70 and/or former water processing establishment 30, so that obtain can recirculation water, describedly can after recirculation water, can be reused for technical process.
Preferably, secondary water circulation is the independently current from substantially pure part, i.e. low chlorine content process water.Low chlorine content process water preferably includes the fiber process Wiring technology water from pipeline, preferably includes Nash pump sealing water, and the total amount of fiber process Wiring technology water is for example 0-5m
3/ Adt, more preferably 1-3m
3/ Adt.As an alternative or supplement, low chlorine content process water preferably includes from the sealing water in recovery boiler and/or desalter region and discharges water, and total amount is for example 0-1m
3/ Adt, more preferably 0.1 – 0.5m
3/ Adt.As an alternative or supplement, low chlorine content process water preferably includes the sealing water from black liquor vaporizing facility, and total amount is for example 0-1m
3/ Adt, more preferably 0.1 – 0.5m
3/ Adt.As an alternative or supplement, low chlorine content process water preferably includes groove overflow and/or the discarded object from drying machine, and total amount is for example maximum 3m
3/ Adt, mostly more preferably is most 0.1m
3/ Adt.As an alternative or supplement, low chlorine content process water preferably includes causticization ejector condenser cooling water, and total amount is for example maximum 4m
3/ Adt, more preferably 1 – 2m
3/ Adt.As an alternative or supplement, low chlorine content process water preferably includes wood working process water, and total amount is for example maximum 2m
3/ Adt, more preferably 1 – 2m
3/ Adt.
Preferably, low chlorine content process water comprise two or three, more preferably four kinds or five kinds, most preferably five kinds or six kinds of above-mentioned water sources.
Most preferably, low chlorine content process water comprise fiber process Wiring technology water/or sealing water.
Preferably, at least 50% or at least 60%, more preferably at least 70% or at least 80%, most preferably at least 90% or at least 95% in all above-mentioned low chlorine content process waters just can again be used as process water without the purification process in waste water disposal facility.
Preferably, for low chlorine content process water 10, there is at least one storage device, for example homogenization groove and/or pond.Fire-fighting and sealing water 60 do not need groove conventionally, and these water can for example be carried by pipeline and without any storage device.
Low chlorine content process water has preferably had low NPE content before optional purification step in purification devices 70 and/or former water processing establishment 30.
Preferably, low chlorine content process water stream had had following characteristics before any purification step:
-Cl content is lower than 200mg/l, and more preferably Cl is less than 100mg/l,
-Ca content is lower than 200mg/l, and more preferably Ca is less than 100mg/l,
-sulphates content is lower than 1,500mg/l, more preferably less than 1,000mg/l,
The pH value of-water is 6.5-10, and
-COD value is lower than 1200mg/l or lower than 1100mg/l, more preferably less than 1000mg/l or lower than 800mg/l, most preferably lower than 500mg/l.
For example, in order to reduce sulphates content and/or the COD value of low chlorine content process water stream, need to carry out purification step, this is because low chlorine content process water stream preferably has following characteristics when again as process water:
-Cl content is lower than 200mg/l,
-Ca content is lower than 110mg/l,
-sulphates content is lower than 200mg/l,
-COD value is lower than 100mg/l,
The pH of-water is 6.5-10, and
-potassium permanganate use amount is less than 25mg/l.
Cl, the Ca of low chlorine content process water 10 and the effluent 20 that comprises bleaching effluent and COD value are obviously different, and in addition, the Cl of the waste water of the purifying of low chlorine content process water 10 and waste water disposal facility, Ca and COD value are also obviously different.Particularly, the chlorinity of low chlorine content process water 10 is obviously different from the chlorinity of effluent 20, is also obviously different from the chlorinity of the waste water of purifying in waste water disposal facility.For example, for bleaching effluent, be 15m at wastewater flow rate
3the NPE content of the pulp mill of/Adt can be as follows:
-Cl content is about 350mg/l, and
-Ca content is about 110mg/l,
And for the waste water of purifying in waste water disposal facility, the NPE content under same case is as follows:
-Cl content is about 440mg/l, and
-Ca content is about 150mg/l.
The COD value of bleaching effluent is about 2500-3000mg/l conventionally, therefore needs to reduce this value, is conventionally undertaken by the method for biologically pure.And the pH of bleaching effluent is obviously different from low chlorine content process water 10, the pH of bleaching effluent is about 4 conventionally.But according to the basicity of effluent or acidity, pH value changes naturally.Conventionally, because the amount of acid bleaching filter liquor is conventionally larger, so the effluent stream merging is acid.
Low chlorine content process water 10 is at least divided into two bursts of logistics according to their COD content.In the part of lower COD, COD content is preferably maximum 600mg/l, for example 40-600mg/l.In an example, the low chlorine content process water 10 than other parts with higher COD is transported in extra purification process, for example, from the process water of wood treatment, wherein COD can be 1300mg/l, and/or from the process water of pulp dryer device, wherein COD can be 800mg/l.
Preferably, in order to realize low chlorine content in low chlorine content process water 10, below part not included in low chlorine content process water, but be directed to effluent 20 and/or waste water disposal facility 40:
-ESP ash leaches and purges thing (ash leaching purge) and/or other ash processing discarded object, conventionally comprises high chlorinity, and
-wood working process water, prerequisite is that EOP bleaching filter liquor is processed for timber.
The 10 preferred at least part of circulations of low chlorine content process water stream re-use in the fire demand water pipeline for washing target (for example, measures as 2m
3/ Adt) and/or for the fire demand water pipeline of target seal.
As an alternative or supplement, low chlorine content process water stream preferred cycle re-uses the gravity table spray thrower in waste water disposal facility, for example, measures as 0.7m
3/ Adt.
As an alternative or supplement, low chlorine content process water stream preferred cycle re-uses in timber processing, for example, measures as 1.2m
3/ Adt.The alkaline pH of this logistics is preferred for timber processing apparatus, otherwise the component of stripping may cause environment acidity there too high from timber.
As an alternative or supplement, low chlorine content process water stream is preferred for the cooling water in ejector condenser to carry out causticization.
In an example, can recirculation water in order to obtain, the low chlorine content process water that will circulate with cost-effective purification process processing.Preferably, the purifying of low chlorine content process water comprises that chemical flocculation stage, clarification stage, sand filtration stage and/or sterilisation stage are as UV, H
2o
2or O
3process.
As an alternative or supplement, at least one purification phase of low chlorine content process water comprised with the flocculation stage of utilizing magnetic iron ore to carry out that is called Johnson's method for sieving (Johnson Screens method).As an alternative or supplement, at least one purification phase of low chlorine content process water comprises the micro-filtration stage.As an alternative or supplement, at least one purification phase of low chlorine content process water comprises oxidation stage.As an alternative or supplement, at least one purification phase of low chlorine content process water comprises ultra-filtration stage.As an alternative or supplement, at least one purification phase of low chlorine content process water comprises the nanofiltration stage.As an alternative or supplement, at least one purification phase of low chlorine content process water comprises another chemistry and/or mechanical purification phase.Preferably, the purifying of low chlorine content process water comprises one, two or three above-mentioned stages.
Can comprise the long-chain organic polymer (CATION, anion or non-ionic polymers or their salt) of for example with or without electric charge for the flocculant in chemical flocculation stage.Preferably, flocculant comprises at least one in following compound, and for example one, two, three, four, five or six:
-polyamine,
-poly-(allyl amine),
-poly-(diallyldimethylammonium chloride),
-poly-(amidoamines),
-poly-(vinyl formamide),
-PVP,
-poly-(vinyl acetamide),
-poly-(vinyl methylformamide),
-poly-(vinyl methylacetamide),
-poly-(dimethylaminopropyl Methacrylamide),
-poly-(dimethyl amino ethyl acrylate),
-poly-(diethylamino ethyl propylene acid esters),
-poly-(acryloyl group ethyl-trimethyl salmiac),
-poly-(acrylamido oxypropyl trimethyl ammonium chloride),
-poly-(methacrylamidopropyltrimethyl trimethyl ammonium chloride),
-poly-(acrylamide), poly-(ethene-imines),
-poly-(oxirane),
-poly-(vinylpyridine),
-Hexadimethrine Bromide (hexadimethrinbromide),
-poly-(dimethyl amine-altogether-chloropropylene oxide),
-poly-(dimethyl amine-altogether-chloropropylene oxide-altogether-ethylenediamine),
-poly-(amidoamines-chloropropylene oxide) or copolymer,
-N-vinyl formamide,
-allyl amine,
-diallyldimethylammonium chloride,
-N-vinyl acetamide,
-NVP,
-N-methyl-N-vinyl formamide,
-N-methyl-N-vinyl acetamide,
-dimethylaminopropyl Methacrylamide,
-dimethyl amino ethyl acrylate,
-diethylamino ethyl propylene acid esters,
-homopolymerization form and/or with acryloyl group ethyl-trimethyl salmiac or the methacrylamidopropyltrimethyl trimethyl ammonium chloride of branched structure,
With
-other flocculant, wherein the degree of functionality of polymer is based on quaternary ammonium group, for example, in the derivative based on starch.
In preferred example, acrylamide and/or polyacrylamide use together with so-called DADMAC (diallyldimethylammonium chloride).As an alternative or supplement, acrylamide preferably reacts with another kind of acrylamide one, forms polyacrylamide.
Preferably, flocculant comprises polyamine.As an alternative or supplement, flocculant comprises poly-(diallyldimethylammonium chloride) (i.e. poly-DADMAC).As an alternative or supplement, flocculant comprises poly-(amidoamines) (being PAA).As an alternative or supplement, flocculant comprises poly-(vinyl formamide) (being PVAm).As an alternative or supplement, flocculant comprises poly-(aziridine) (being PEI).As an alternative or supplement, flocculant forms by homopolymerization form and/or with the form of branched structure, and wherein the degree of functionality of polymer is based on quaternary ammonium group, for example, in the derivative based on starch.One preferred embodiment in, two or three, more preferably four kinds, most preferably five kinds of above-mentioned flocculants use together.
As the substituting or supplementing of flocculant, other compound can be used for purification phase as coagulating agent and/or adsorbent.
Coagulating agent can comprise aluminium compound.Preferably, aluminium compound comprises aluminum nitrate.As an alternative or supplement, aluminium compound comprises aluminium chloride.As an alternative or supplement, aluminium compound comprises alum and their polymerized form, for example poly-aluminum nitrate (PAN), polyaluminium chloride (PAC) and/or poly aluminium sulfate (PAS).
As an alternative or supplement, coagulating agent comprises ferrous compound, for example FeCl
2and/or FeSO
4.As an alternative or supplement, coagulating agent comprises ferric iron compound, for example FeCl
3and/or Fe
2(SO
4)
3.
Adsorbent can comprise for example clay, bentonite and/or talcum.
Preferably, ash is processed to waste streams (preferably comprise ash and leach purging thing) and be transported to effluent stream 20.Preferably, be also transported to effluent stream 20 from acidity and the basic stream of bleaching.This effluent stream 2 is preferably directed to waste water disposal facility 40.In an example, owing to will being transported to quantity and the quality of effluent of waste water disposal facility, for example, due to the concentrated load of lower volume, particularly there is the lower-molecular-weight component of high COD, existing aerobic treatment in waste water disposal facility is changed.Preferably, comprise according to waste water disposal facility of the present invention:
-anaerobic reactor+aerobic treatment, or
-anaerobic reactor+membrane bioreactor.
One of ordinary skill in the art will readily recognize that different embodiment of the present invention can be applied in the environment that need to be optimized the liquid stream of pulp mill.Therefore, obviously the present invention is not limited in above-mentioned embodiment, but can modify within the scope of the appended claims.
Claims (12)
1. in a method for chemical pulp mills treatment fluid stream, this system comprises:
-for the production of the boiling process of paper pulp,
-at least one is for washing the washing stage of described paper pulp,
-at least one is for bleaching the bleaching stage of described paper pulp,
-waste water disposal facility (40),
-former water processing establishment (30), and
-timber processing apparatus (50),
Wherein, described method comprises:
-low chlorine content process water is divided into at least two bursts of logistics according to their COD content,
-at least a portion low chlorine content process water is transported to chemical pulp mills, to be again used as process water.
2. the method for claim 1, is characterized in that, described method comprises: the low chlorine content process water with higher COD content is transported to extra purification process.
3. method as claimed in claim 2, is characterized in that, in the low chlorine content process water with higher COD content, COD content exceedes 600mg/l.
4. the method as described in any one in claim 1-3, is characterized in that, described low chlorine content process water comprises following at least one in listed:
-from the fiber process Wiring technology water of pipeline,
-from the sealing water in recovery boiler region,
-from the discharge water in recovery boiler region,
-from the sealing water of desalination facility,
-carry out the sealing water of spontaneous evaporation facility,
-from the discarded object of drying machine,
-from the groove overflow of drying machine,
-causticization ejector condenser cooling water, or
-wood working process water.
5. the method according to any one of the preceding claims, is characterized in that, the Cl content of low chlorine content process water is lower than 200mg/l, preferably lower than 100mg/l.
6. the method according to any one of the preceding claims, is characterized in that, the Ca content of low chlorine content process water is lower than 200mg/l, preferably lower than 100mg/l.
7. the method according to any one of the preceding claims, is characterized in that, the pH of low chlorine content process water is 6.5-10.
8. the method according to any one of the preceding claims, is characterized in that, the low chlorine content process water of at least a portion is transported in the following facility of pulp mill and uses:
-fire demand water pipeline, for washing target,
-fire demand water pipeline, for target seal,
-waste water disposal facility, for gravity table spray thrower,
-timber processing apparatus, or
-ejector condenser, as causticization cooling water.
9. the method according to any one of the preceding claims, is characterized in that, described method comprises:
-ash of chemical pulp mills is processed to waste streams be transported to the effluent stream (20) of processing in waste water disposal facility (40).
10. the method according to any one of the preceding claims, is characterized in that, described low chlorine content process water stream utilizes at least one in following technology to carry out purifying at least one purification phase, then again as process water:
-chemical flocculation technology,
-clarification technique,
-filtering technique,
-disinfection technology,
-micro-filtration technology,
-oxidation technology,
-hyperfiltration technique, or
-nanofiltration technique.
11. 1 kinds of systems at chemical pulp mills treatment fluid stream, this system comprises:
-for the digestion facility of boiling paper pulp,
-for the washing facility of washing pulp,
-bleaching equipment,
-waste water disposal facility (40),
-former water processing establishment (30), and
-timber processing apparatus (50),
Wherein, this system also comprises:
-equipment be applicable at least a portion low chlorine content process water to be transported at least one of chemical pulp mills processing stage.
The application of 12. low chlorine content process waters at least one following facility of chemical pulp mills:
-fire demand water pipeline, for washing and/or sealing purpose,
The gravity table of-waste water disposal facility, for shower water,
-timber processing apparatus, for washing object, or
-ejector condenser, for causticization cooling water;
Described chemical pulp mills comprises:
-for the digestion facility of boiling paper pulp,
-for the washing facility of washing pulp,
-bleaching equipment,
-waste water disposal facility (40),
-former water processing establishment (30), and
-timber processing apparatus (50).
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI20125264 | 2012-03-12 | ||
| FI20125264A FI128900B (en) | 2012-03-12 | 2012-03-12 | A method for treating liquid flows at a chemical pulp mill and use of low chloride content process waters at a chemical pulp mill |
| PCT/FI2013/050269 WO2013135956A2 (en) | 2012-03-12 | 2013-03-12 | A method and a system for treating liquid flows at a chemical pulp mill |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104169493A true CN104169493A (en) | 2014-11-26 |
| CN104169493B CN104169493B (en) | 2016-09-07 |
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| CN201380014049.6A Active CN104169493B (en) | 2012-03-12 | 2013-03-12 | A kind of method and system processing liquid flow in chemical pulp mills |
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|---|---|
| CN (1) | CN104169493B (en) |
| BR (1) | BR112014022420B1 (en) |
| FI (1) | FI128900B (en) |
| RU (1) | RU2634894C2 (en) |
| UY (1) | UY34673A (en) |
| WO (1) | WO2013135956A2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104878636A (en) * | 2015-04-23 | 2015-09-02 | 中国制浆造纸研究院 | Refined cotton production and pollutant treatment method |
| CN108349761A (en) * | 2015-11-04 | 2018-07-31 | 凯米罗总公司 | Method for optimizing the material recovery in chemical pulping process |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE542676C2 (en) * | 2017-11-29 | 2020-06-23 | Axolot Solutions Ab | Method and a system for washing paper pulp |
| SE2230351A1 (en) * | 2022-11-02 | 2024-05-03 | Valmet Oy | Pulp mill |
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| US5938892A (en) * | 1991-01-28 | 1999-08-17 | Champion International Corporation | Process for recycling bleach plant filtrate |
| CN101688362A (en) * | 2007-06-15 | 2010-03-31 | 安德里兹公司 | Method for treating liquid flows at a chemical pulp mill |
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|---|---|---|---|---|
| CA1113207A (en) * | 1978-04-19 | 1981-12-01 | Allan F. Gilbert | Removal of potassium values from pulp mill liquors |
| US5853535A (en) * | 1991-01-28 | 1998-12-29 | Champion International Corporation | Process for manufacturing bleached pulp including recycling |
| US5549788A (en) * | 1992-07-30 | 1996-08-27 | A. Ahlstrom Corporation | Minimal effluents discharge pulp mill with chemical recovery |
| AU7720094A (en) * | 1993-09-02 | 1995-03-22 | Union Camp Patent Holding, Inc. | Improved method for bleaching lignocellulosic pulp |
| US5626717A (en) * | 1995-06-01 | 1997-05-06 | International Paper Company | Oxidative treatment of bleach plant effluent |
| US6569284B1 (en) * | 1996-09-24 | 2003-05-27 | International Paper Company | Elemental-chlorine-free bleaching process having an initial Eo or Eop stage |
| EP0863113A1 (en) * | 1997-03-07 | 1998-09-09 | Akzo Nobel N.V. | Process for treating wastewater |
| RU2211836C1 (en) * | 2002-04-24 | 2003-09-10 | Кочетов Анатолий Сергеевич | Method of processing larch wood to isolate dehydroquercitine and apparatus |
-
2012
- 2012-03-12 FI FI20125264A patent/FI128900B/en active IP Right Grant
-
2013
- 2013-03-12 UY UY0001034673A patent/UY34673A/en active IP Right Grant
- 2013-03-12 RU RU2014136219A patent/RU2634894C2/en active
- 2013-03-12 BR BR112014022420-0A patent/BR112014022420B1/en active IP Right Grant
- 2013-03-12 CN CN201380014049.6A patent/CN104169493B/en active Active
- 2013-03-12 WO PCT/FI2013/050269 patent/WO2013135956A2/en active Application Filing
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5938892A (en) * | 1991-01-28 | 1999-08-17 | Champion International Corporation | Process for recycling bleach plant filtrate |
| CN101688362A (en) * | 2007-06-15 | 2010-03-31 | 安德里兹公司 | Method for treating liquid flows at a chemical pulp mill |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104878636A (en) * | 2015-04-23 | 2015-09-02 | 中国制浆造纸研究院 | Refined cotton production and pollutant treatment method |
| CN108349761A (en) * | 2015-11-04 | 2018-07-31 | 凯米罗总公司 | Method for optimizing the material recovery in chemical pulping process |
Also Published As
| Publication number | Publication date |
|---|---|
| FI128900B (en) | 2021-02-26 |
| BR112014022420B1 (en) | 2021-06-29 |
| CN104169493B (en) | 2016-09-07 |
| BR112014022420A2 (en) | 2017-06-20 |
| WO2013135956A2 (en) | 2013-09-19 |
| WO2013135956A3 (en) | 2013-11-21 |
| RU2634894C2 (en) | 2017-11-07 |
| FI20125264L (en) | 2013-09-13 |
| RU2014136219A (en) | 2016-05-10 |
| UY34673A (en) | 2013-10-31 |
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