CA2060073C - Method for reducing slime formation in plants having a water cycle - Google Patents
Method for reducing slime formation in plants having a water cycle Download PDFInfo
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- CA2060073C CA2060073C CA002060073A CA2060073A CA2060073C CA 2060073 C CA2060073 C CA 2060073C CA 002060073 A CA002060073 A CA 002060073A CA 2060073 A CA2060073 A CA 2060073A CA 2060073 C CA2060073 C CA 2060073C
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- lignosulfonate
- molecular weight
- water
- average molecular
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Classifications
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
- A01N65/00—Biocides, pest repellants or attractants, or plant growth regulators containing material from algae, lichens, bryophyta, multi-cellular fungi or plants, or extracts thereof
- A01N65/08—Magnoliopsida [dicotyledons]
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
- A01N61/00—Biocides, pest repellants or attractants, or plant growth regulators containing substances of unknown or undetermined composition, e.g. substances characterised only by the mode of action
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
- A01N65/00—Biocides, pest repellants or attractants, or plant growth regulators containing material from algae, lichens, bryophyta, multi-cellular fungi or plants, or extracts thereof
-
- A—HUMAN NECESSITIES
- A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
- A01N—PRESERVATION OF BODIES OF HUMANS OR ANIMALS OR PLANTS OR PARTS THEREOF; BIOCIDES, e.g. AS DISINFECTANTS, AS PESTICIDES OR AS HERBICIDES; PEST REPELLANTS OR ATTRACTANTS; PLANT GROWTH REGULATORS
- A01N65/00—Biocides, pest repellants or attractants, or plant growth regulators containing material from algae, lichens, bryophyta, multi-cellular fungi or plants, or extracts thereof
- A01N65/08—Magnoliopsida [dicotyledons]
- A01N65/30—Polygonaceae [Buckwheat family], e.g. red-knees or rhubarb
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/50—Treatment of water, waste water, or sewage by addition or application of a germicide or by oligodynamic treatment
-
- 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
- D21C9/008—Prevention of corrosion or formation of deposits on pulp-treating equipment
Abstract
The invention relates to a method of reducing slime for-mation in plants in which water is recycled, whereby a ligno-sulfonate is added to the water. The lignosulfonate is pro-duced by a special method and has a special composition, which leads to a surprisingly good effect of the added lignosul-fonate.
Description
A method of reducing slime formation in plants having a water cycle The present invention relates to an improved method of reducing slime formation in plants in which water is recycled, whereby a lignosulfonate is added to the recycling water.
Microorganisms often find ideal breeding conditions in the water cycles of plants. zn particular the white water of paper machines, which is increasingly circulated in a closed cycle, provides ideal conditions in terms of the inorganic and organic nutrient supply, temperature, pH value and oxygen con-tent for their unlimited breeding. This leads; to a dramati-cally high degree of slime formation on the uralls of the parts, such as the pipes, vessels and pumps, of the plant used for cycling the white water. The detachment csf slimy parts from the walls leads to the formation of lumps and holes in the paper web_ This weakens the paper web, i.e. breaks can oc cur in the paper web, resulting necessarily 3.n machine down-time. ' In the paper industry, considerable amounts of biocides are therefore traditionally added to the papear machine cycles during the production sequence to control bacaerial growth_ Such biocides can destroy the bacteria causing slime forma-tion. However, due to the action and function of biocidal slime control agents they must have no fiber affinity. They therefore.do not remain in the paper but leave. the paper fac-tory in the waste water. The white water contains not only the bacteria but also fungi, so that fungicides must additionally be used. The known method, also known as the "total kill"
method, is therefore not only very expensive but also results in an environmental load.
_ 2 - ~Q~~~'; 3 In the interests of environmental protection, but also for financial reasons, it has therefore been an objective in the paper manufacturing branch to reduce slinxe formation in recycling water plants using environmentally acceptable but nevertheless effective means.
U.S.-A-2,551,446 describes the use of a cuprous salt, e.g. copper sulfate, to prevent the growth of microorganisms in water. To prevent the copper sulfate from precipitating one uses a lignosulfonate as a complexing agent. CA-A-80?,123 dis-closes the use of halogenated levulinic acid as a biocide.
Since halogenated levulinic acid is only slightly soluble in water, lignosulfonic acid and dimethyl sulfo:xide are proposed as dispersing agents. ' It is known from "Das osterreichische Papier" 20, no. 9, 34-35, to add a lignosulfonate together with a biocide to the white water of a.paper machine. This retakes it possible to re-duce the amount of biocide added. .
It is assumed that the lignosulfonate neutralizes by electrostatic charge equalization the metabolic products act-ing as a food bridge to the cycling system, thereby making them useless for the food supply. This controls the bacterial activity and thus also the fungal attack. Th.e mentioned arti-cle states that a °'specially selected and modified lignosul-fonate" is used as a biological complexing agent. Zt is not mentioned which "specially selected and modified lignosul-fonate" this is. Commercial lignosulfonates are in any case unsuitable for the stated purpose, as experiments have shown.
European patent no. 0 185 963, which is from the same ap-plicant, discloses a method of reducing slime formation in water cycles using a .lignosulfonate having a weight-average molecular weight of 4000 to ?000 (number average.2000 to 2~s~~~: ~
Microorganisms often find ideal breeding conditions in the water cycles of plants. zn particular the white water of paper machines, which is increasingly circulated in a closed cycle, provides ideal conditions in terms of the inorganic and organic nutrient supply, temperature, pH value and oxygen con-tent for their unlimited breeding. This leads; to a dramati-cally high degree of slime formation on the uralls of the parts, such as the pipes, vessels and pumps, of the plant used for cycling the white water. The detachment csf slimy parts from the walls leads to the formation of lumps and holes in the paper web_ This weakens the paper web, i.e. breaks can oc cur in the paper web, resulting necessarily 3.n machine down-time. ' In the paper industry, considerable amounts of biocides are therefore traditionally added to the papear machine cycles during the production sequence to control bacaerial growth_ Such biocides can destroy the bacteria causing slime forma-tion. However, due to the action and function of biocidal slime control agents they must have no fiber affinity. They therefore.do not remain in the paper but leave. the paper fac-tory in the waste water. The white water contains not only the bacteria but also fungi, so that fungicides must additionally be used. The known method, also known as the "total kill"
method, is therefore not only very expensive but also results in an environmental load.
_ 2 - ~Q~~~'; 3 In the interests of environmental protection, but also for financial reasons, it has therefore been an objective in the paper manufacturing branch to reduce slinxe formation in recycling water plants using environmentally acceptable but nevertheless effective means.
U.S.-A-2,551,446 describes the use of a cuprous salt, e.g. copper sulfate, to prevent the growth of microorganisms in water. To prevent the copper sulfate from precipitating one uses a lignosulfonate as a complexing agent. CA-A-80?,123 dis-closes the use of halogenated levulinic acid as a biocide.
Since halogenated levulinic acid is only slightly soluble in water, lignosulfonic acid and dimethyl sulfo:xide are proposed as dispersing agents. ' It is known from "Das osterreichische Papier" 20, no. 9, 34-35, to add a lignosulfonate together with a biocide to the white water of a.paper machine. This retakes it possible to re-duce the amount of biocide added. .
It is assumed that the lignosulfonate neutralizes by electrostatic charge equalization the metabolic products act-ing as a food bridge to the cycling system, thereby making them useless for the food supply. This controls the bacterial activity and thus also the fungal attack. Th.e mentioned arti-cle states that a °'specially selected and modified lignosul-fonate" is used as a biological complexing agent. Zt is not mentioned which "specially selected and modified lignosul-fonate" this is. Commercial lignosulfonates are in any case unsuitable for the stated purpose, as experiments have shown.
European patent no. 0 185 963, which is from the same ap-plicant, discloses a method of reducing slime formation in water cycles using a .lignosulfonate having a weight-average molecular weight of 4000 to ?000 (number average.2000 to 2~s~~~: ~
3000)_ This method achieves goad results in reducing sline formation.
However, operation has shown that the known special lig-nosulfonate does not fully meet the requiremE~nts_ It fails when the flow is reduced or fully lacking in the water cycle, for example in certain areas of the plant.
The present invention is based on the problem of overcom-ing this disadvantage, in particular of providing a lignosul-fonate product having improved properties for preventing slime formation.
It was assumed that the efficacy of the ltnowr.'lignosul-fonate is based on its low viscosity and thus its low molecu-lar weight_ On this assuinptiori lignosulfonates were produced by fractionation so as to have an even lower molecular weight.
However, these lignosulfonates showed little or no improve-went.
surprisingly enough, an abrupt improvement in the reduc-tion of slime formation occurs if a lignosulfonate is used which is produced by mixing a calcium-impoverished sulfite lye of an acidic wood sulfite pulp with an amount of calcium hy-droxide which suffices to deposit calcium lignvsulfonate with a higher molecular weight, and treating the remaining soluble part with sodium sulfate and sulfuric acid t.o separate the calcium largely in the form of calcium sulfate out of the sul-fite lye which contains the lignosulfonate, and optionally concentrating the sulfite lye containing they lignosulfonate.
The use of this lignosulfonate leads tc> a considerable improvement in the break data during operation of a paper ma-chine. One reason for this is presumably that the lignosul-fonate shows an elevated effect even when there is less or no - 4 - 2~~~~~3 flow in the water recycling. When the fouling situation in the paper machine cycle is quantitatively reduced and qualita-tively improved, this obviously reduces the machine s suscep-tibility to disturbance with respect to breaks, lumps or holes in the paper web due to fouling.
The weight-average molecular weight of the inventively used lignosulfonate is preferably 8000 to 15000; the number-average molecular weight is 1000 to 3000.
The molecular weight of the inventively added lignvsul-fonate is preferably about 12700 on the weight average and about 1564 on the number average. In a further preferred em-bodiment the molecular weight of the added lignosulfonate is 8500 on the weight average and 1500 on the number average.
With these lignosulfonates one obtains particularly good and stable results.
Surprisingly enough, a lignosulfonate product having a higher molecular weight than the known lignosulfonate product thus leads to an improvement in the reduction of slime forma-tion. It is assumed that this is mainly due to the content of oligosaccharides of i2 to 16 weight percent.
Further characteristics of the inventively used lignosul-fonate are that it is obtained from a wood consisting at least partly of softwood, whereby this product has a low content of reducing sugars of at most 1.0 weight percent. It is known that reducing sugars support the growth of microorganisms. The degree of sulfonation of the lignosulfonate product is prefer-ably 1.2 to 1.5.
A further feature of the inventively used lignosulfonate product is that it contains a quantitative share of 40-55~
short-chain (1-5 pentose and/or hexose units} of partly oxida--- 5 - ~~~? ~":73 tively altered fragments of cellulose and cellulose accompany-ing substances.
The lignosulfonate can be used in the inventive mathod in a concentration of 0.1 g to 1.0 g/m3 water. The lignosulfonate is charged continuously. To further reduce any lump formation one can also add to the recycling water smal:L amounts of the bioaides known for this purpose, The biocide is added periodi-cally, the time during which biocide is added being 4 to 50%
the time during which lignosulfonate is added.
The biocides used m~:y be one or more organic sulfur-ni-trogen compounds or organic bromine-nitrogen compounds, e.g.
methylene-bis-thiocyanate or carbamates or 2,2-dibromo-2-cyanoacetamide or 3,5-dimethyl-1,3,5-2H-tetrahydrothiadiazine-2-thion:
The advantageousness of the inventive method shall be shown in the following with reference to comparative experi-ments. For this purpose, the lignosulfonate known from Euro-pean patent nr~. 0 185 963 (product A), a commercial product (product X) and the inventively used product: (product B) Will.
be contrasted.
The inventively used, repeatedly fractionated and modi-fied product is produced as follows.
Wood chips are subjected to the customary conditions of sulfite pulping.
44 parts by weight of calcium hydroxide (Ca(OH)2) are added to 272 parts by weight of the sulfite lye of the acidic wood sulfite pulp, which is poor in calcium and contains 45~
solids. The separated calcium lignosulfanat~e with a higher molecular weight is removed by filtration. 22 parts by, weight - 6 - ~0~'~~': .'3 of 36% sulfuric acid {H2SO4) are added to the filtrate per 130 parts by weight of solids. The separated calcium sulfate is removed by filtration and the filtrate is concentrated by evaporation to 40~ solids content. To 102 parts by weight of this, 16 parts by weight of sodium sulfate (Na2S04) and 2.3 parts by weight of sulfuric acid (H2S04) are added. The cal-cium sulfate deposit is removed by filtration and sodium hy-droxide is added to the filtrate to set the pH to 7.5_ One thereby obtains 100 parts by weight of solids of the product, and the solution can optionally be concentrated further-.
The obtained product has the following .composition in %:
Total s W 3 Unsulfon. S 0g Sulfon. S 54 Na i1.0 Ca 0.6 Phenolic OH 1_2 OCH3 5.6 Sugar 0-5 Na lignosulfonate 43 The resulting product has a weight-average molecular weight of about 12700 or a number average of about 1570. Obvi-ously, other molecular weights within the c=Laimed range can be obtained by slightly varying the described method. The content . . of oligosaccharides in the obtained product is about 14 weight percent.
Experiment 1 In a paper machine (300 TATO Production Wood-free/Coated) lignosulfonate products A, B and X were each used for a period of three months. The average number of breaks in the paper - ~ - ~Qf ~ ~": '3 webs, which is a criterion for slime and fouling control in paper machine cycles, was determined. Product. parameters and results are shown in Table 1.
The Table indicates that an improvement in the break num-ber can be obtained with a lignosulfonate product according to the present invention. In comparison to a lignosulfonate ac-cording to European patent no. 0 185 963 the improvement is Zo~; in comparison to commercial lignosulfonates it is even 20~.
~x~er invent 2 Cultures of ~li.me-forming bacteria, for example Pseu-domonas fluorescens, were each mixed with so_Lutions of ligno-sulfonate A, B and X. Capillary flow time measurement (glass capillaries, liquid volume sent through and pressure condi-tions are constant) was used to determine time-dependent changes in viscosity. Simultaneously a blank test, i_e. With no addition of lignosulfonate, was made. The nutrient broths were stirred for a period of 24 hours and thereafter the agi-tator was switched off. The result is shown ,in Table 2.
As indicated in Table 2, viscosity increases considerably during an operating time of lOD hours when n~o lignosulfonate is added_ By contrast, lignosulfonates A and B substantially prevent an increase in viscosity.
An interruption of the circulation causes a pronounced increase in the viscosity of the cultures that are nixed with lignosulfonate A or contain no additive. The culture with lig-nosulfonate 8 added shows virtually no increase in viscosity.
Thus, while lignosulfonates A and B can prevent the formation of bacterial slime in moving systems, such as the piping arid troughs carrying pulp or white water in a paper machine, the - a - ~0~~~~3 inventively used lignosulfonate B provides the essential addi-tional effect of reducing slime formation even in nonmoving systems. This is of crucial importance for those critical zones in a paper machine cycling system which are character-ized by a highly reduced or fully lacking flow. slime forma-tion generally occurs first and to a greater degree in such places.
Obviously, this effect provided by the .inventively used lignosulfonate is of crucial importance for the method. It can substantially improve the break number. .
An improved break number simultaneously improves the economy of the method, since less unwanted machine down-time is required.
- 9 - ~os~~:~~
Table l Mw Degree of oligosaccharides (%) Breaks) sulfonat=Lon (%) 100 tons A X000-7000 1.2 - 1.5 25 - 40 2.75 B 12700 1.2 - 1.5 12 - 16 2.5 X ~ 50 . 000 0 . 7 undef fined 3 . 2 Table 2 Increase in viscosity (~~) Product Starting After 100 h with After 100 h more value circulation w/o circulation 1.1 3.1 1.1 1.3 W/o additive 1 1.7 3.4
However, operation has shown that the known special lig-nosulfonate does not fully meet the requiremE~nts_ It fails when the flow is reduced or fully lacking in the water cycle, for example in certain areas of the plant.
The present invention is based on the problem of overcom-ing this disadvantage, in particular of providing a lignosul-fonate product having improved properties for preventing slime formation.
It was assumed that the efficacy of the ltnowr.'lignosul-fonate is based on its low viscosity and thus its low molecu-lar weight_ On this assuinptiori lignosulfonates were produced by fractionation so as to have an even lower molecular weight.
However, these lignosulfonates showed little or no improve-went.
surprisingly enough, an abrupt improvement in the reduc-tion of slime formation occurs if a lignosulfonate is used which is produced by mixing a calcium-impoverished sulfite lye of an acidic wood sulfite pulp with an amount of calcium hy-droxide which suffices to deposit calcium lignvsulfonate with a higher molecular weight, and treating the remaining soluble part with sodium sulfate and sulfuric acid t.o separate the calcium largely in the form of calcium sulfate out of the sul-fite lye which contains the lignosulfonate, and optionally concentrating the sulfite lye containing they lignosulfonate.
The use of this lignosulfonate leads tc> a considerable improvement in the break data during operation of a paper ma-chine. One reason for this is presumably that the lignosul-fonate shows an elevated effect even when there is less or no - 4 - 2~~~~~3 flow in the water recycling. When the fouling situation in the paper machine cycle is quantitatively reduced and qualita-tively improved, this obviously reduces the machine s suscep-tibility to disturbance with respect to breaks, lumps or holes in the paper web due to fouling.
The weight-average molecular weight of the inventively used lignosulfonate is preferably 8000 to 15000; the number-average molecular weight is 1000 to 3000.
The molecular weight of the inventively added lignvsul-fonate is preferably about 12700 on the weight average and about 1564 on the number average. In a further preferred em-bodiment the molecular weight of the added lignosulfonate is 8500 on the weight average and 1500 on the number average.
With these lignosulfonates one obtains particularly good and stable results.
Surprisingly enough, a lignosulfonate product having a higher molecular weight than the known lignosulfonate product thus leads to an improvement in the reduction of slime forma-tion. It is assumed that this is mainly due to the content of oligosaccharides of i2 to 16 weight percent.
Further characteristics of the inventively used lignosul-fonate are that it is obtained from a wood consisting at least partly of softwood, whereby this product has a low content of reducing sugars of at most 1.0 weight percent. It is known that reducing sugars support the growth of microorganisms. The degree of sulfonation of the lignosulfonate product is prefer-ably 1.2 to 1.5.
A further feature of the inventively used lignosulfonate product is that it contains a quantitative share of 40-55~
short-chain (1-5 pentose and/or hexose units} of partly oxida--- 5 - ~~~? ~":73 tively altered fragments of cellulose and cellulose accompany-ing substances.
The lignosulfonate can be used in the inventive mathod in a concentration of 0.1 g to 1.0 g/m3 water. The lignosulfonate is charged continuously. To further reduce any lump formation one can also add to the recycling water smal:L amounts of the bioaides known for this purpose, The biocide is added periodi-cally, the time during which biocide is added being 4 to 50%
the time during which lignosulfonate is added.
The biocides used m~:y be one or more organic sulfur-ni-trogen compounds or organic bromine-nitrogen compounds, e.g.
methylene-bis-thiocyanate or carbamates or 2,2-dibromo-2-cyanoacetamide or 3,5-dimethyl-1,3,5-2H-tetrahydrothiadiazine-2-thion:
The advantageousness of the inventive method shall be shown in the following with reference to comparative experi-ments. For this purpose, the lignosulfonate known from Euro-pean patent nr~. 0 185 963 (product A), a commercial product (product X) and the inventively used product: (product B) Will.
be contrasted.
The inventively used, repeatedly fractionated and modi-fied product is produced as follows.
Wood chips are subjected to the customary conditions of sulfite pulping.
44 parts by weight of calcium hydroxide (Ca(OH)2) are added to 272 parts by weight of the sulfite lye of the acidic wood sulfite pulp, which is poor in calcium and contains 45~
solids. The separated calcium lignosulfanat~e with a higher molecular weight is removed by filtration. 22 parts by, weight - 6 - ~0~'~~': .'3 of 36% sulfuric acid {H2SO4) are added to the filtrate per 130 parts by weight of solids. The separated calcium sulfate is removed by filtration and the filtrate is concentrated by evaporation to 40~ solids content. To 102 parts by weight of this, 16 parts by weight of sodium sulfate (Na2S04) and 2.3 parts by weight of sulfuric acid (H2S04) are added. The cal-cium sulfate deposit is removed by filtration and sodium hy-droxide is added to the filtrate to set the pH to 7.5_ One thereby obtains 100 parts by weight of solids of the product, and the solution can optionally be concentrated further-.
The obtained product has the following .composition in %:
Total s W 3 Unsulfon. S 0g Sulfon. S 54 Na i1.0 Ca 0.6 Phenolic OH 1_2 OCH3 5.6 Sugar 0-5 Na lignosulfonate 43 The resulting product has a weight-average molecular weight of about 12700 or a number average of about 1570. Obvi-ously, other molecular weights within the c=Laimed range can be obtained by slightly varying the described method. The content . . of oligosaccharides in the obtained product is about 14 weight percent.
Experiment 1 In a paper machine (300 TATO Production Wood-free/Coated) lignosulfonate products A, B and X were each used for a period of three months. The average number of breaks in the paper - ~ - ~Qf ~ ~": '3 webs, which is a criterion for slime and fouling control in paper machine cycles, was determined. Product. parameters and results are shown in Table 1.
The Table indicates that an improvement in the break num-ber can be obtained with a lignosulfonate product according to the present invention. In comparison to a lignosulfonate ac-cording to European patent no. 0 185 963 the improvement is Zo~; in comparison to commercial lignosulfonates it is even 20~.
~x~er invent 2 Cultures of ~li.me-forming bacteria, for example Pseu-domonas fluorescens, were each mixed with so_Lutions of ligno-sulfonate A, B and X. Capillary flow time measurement (glass capillaries, liquid volume sent through and pressure condi-tions are constant) was used to determine time-dependent changes in viscosity. Simultaneously a blank test, i_e. With no addition of lignosulfonate, was made. The nutrient broths were stirred for a period of 24 hours and thereafter the agi-tator was switched off. The result is shown ,in Table 2.
As indicated in Table 2, viscosity increases considerably during an operating time of lOD hours when n~o lignosulfonate is added_ By contrast, lignosulfonates A and B substantially prevent an increase in viscosity.
An interruption of the circulation causes a pronounced increase in the viscosity of the cultures that are nixed with lignosulfonate A or contain no additive. The culture with lig-nosulfonate 8 added shows virtually no increase in viscosity.
Thus, while lignosulfonates A and B can prevent the formation of bacterial slime in moving systems, such as the piping arid troughs carrying pulp or white water in a paper machine, the - a - ~0~~~~3 inventively used lignosulfonate B provides the essential addi-tional effect of reducing slime formation even in nonmoving systems. This is of crucial importance for those critical zones in a paper machine cycling system which are character-ized by a highly reduced or fully lacking flow. slime forma-tion generally occurs first and to a greater degree in such places.
Obviously, this effect provided by the .inventively used lignosulfonate is of crucial importance for the method. It can substantially improve the break number. .
An improved break number simultaneously improves the economy of the method, since less unwanted machine down-time is required.
- 9 - ~os~~:~~
Table l Mw Degree of oligosaccharides (%) Breaks) sulfonat=Lon (%) 100 tons A X000-7000 1.2 - 1.5 25 - 40 2.75 B 12700 1.2 - 1.5 12 - 16 2.5 X ~ 50 . 000 0 . 7 undef fined 3 . 2 Table 2 Increase in viscosity (~~) Product Starting After 100 h with After 100 h more value circulation w/o circulation 1.1 3.1 1.1 1.3 W/o additive 1 1.7 3.4
Claims (13)
1. A method of reducing slime formation in plants in which water is recycled, whereby a lignosulfonate is added to the water, characterized in that the lignosulfonate is pro-duced by mixing a calcium-impoverished sulfite lye of an acidic wood sulfite pulp with an amount of calcium hydroxide which suffices to deposit calcium lignosulfonate with a higher molecular weight, and treating the remaining soluble part with sodium sulfate and sulfuric acid to separate the calcium largely in the form of calcium sulfate out of the sulfite lye which contains the lignosulfonate, and optionally concentrat-ing the sulfite lye containing the lignosulfonate.
2. The method of claim 1, characterized in that the lig-nosulfonate has a weight-average molecular weight of 8000 to 15000 or a number-average molecular weight of 1000 to 3000.
3. The method of claim 1, characterized in that the lig-nosulfonate has a weight-average molecular weight of 12700 or a number-average molecular weight of 1564.
4. The method of claim 1 and/or 2, characterized in that the lignosulfonate has a weight-average molecular weight of 8500 or a number-average molecular weight of 1500.
5. The method of at least one or more of the above claims, characterized in that the lignosulfonate product con-tains 40-55% short-chain, partly oxidatively altered fragments of cellulose and accompanying substances thereof.
6. The method of claim 5, characterized in that the lig-nosulfonate has a share of oligosaccharides of 12 to 16 wt%.
7. The method of at least one of claims 1 to 6, charac-terized in that the lignosulfonate has a share of reducing sugars of at most 1 wt%.
8. The method of one or more of the above claims, charac-terized in that the lignosulfonate has a degree of sulfonation of 1.2 to 1.5.
9. The method of one or more of the above claims, charac-terized in that the lignosulfonate is added in an amount of 0.1 to 1.0 g/m3 water.
10. The method of one or more of the above claims, char-acterized in that the lignosulfonate is obtained from a wood consisting at least partly of softwood.
11. The method of one or more of the above claims, char-acterized in that a biocide is added additionally.
12. The method of claim 11, characterized in that the biocide is used in an amount of 0.01 to 2.0 g/t water.
13. The application of the method of one of the above claims for reducing slime formation in a plant that recycles the white water of paper machines.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP91101061.9 | 1991-01-28 | ||
| EP91101061A EP0496905B1 (en) | 1991-01-28 | 1991-01-28 | Lignosulfonates for combatting slimy deposits in closed water loop plants, process of preparation and their use |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2060073A1 CA2060073A1 (en) | 1992-07-29 |
| CA2060073C true CA2060073C (en) | 2002-06-25 |
Family
ID=8206334
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002060073A Expired - Lifetime CA2060073C (en) | 1991-01-28 | 1992-01-27 | Method for reducing slime formation in plants having a water cycle |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0496905B1 (en) |
| AT (1) | ATE105267T1 (en) |
| CA (1) | CA2060073C (en) |
| DE (1) | DE59101575D1 (en) |
| DK (1) | DK0496905T3 (en) |
| ES (1) | ES2056500T3 (en) |
| FI (1) | FI104817B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4410271C2 (en) * | 1994-03-24 | 1999-02-25 | Lumos Trading & Investments Co | Process for reducing the formation of slime and deposits in systems in which water from paper and pulp machines is circulated, as well as in systems in which cooling water is circulated |
| GB9615262D0 (en) * | 1996-07-20 | 1996-09-04 | Kodak Ltd | Method for inhibiting the growth of microorganisms in an aqueous medium |
| AU1817199A (en) * | 1997-12-30 | 1999-07-19 | Clorox Company, The | Water purification filter |
| DE10017012A1 (en) * | 2000-03-16 | 2001-09-27 | Bioconsult Ges Fuer Biotechnol | Process for reducing slime and deposit formation in (partly) closed systems conveying water or aqueous media, e.g. in paper machines or cooling water cycle, involves adding sulfur-free lignin or derivative |
| SE531688C2 (en) * | 2007-11-22 | 2009-07-07 | Bim Kemi Ab | Sales control in a paper-making system |
| DE102017011116A1 (en) | 2017-11-30 | 2019-06-06 | Alfred Pohlen | Online cleaner for water-bearing or water-contacting systems |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4127383A (en) * | 1977-06-10 | 1978-11-28 | Graham-White Sales Corporation | Foaming waste treatment composition and method for treating nitrogenous waste material therewith |
| DE3447686C1 (en) * | 1984-12-28 | 1986-10-30 | Jörg Dipl.-Ing. Dr. Seewalchen Oberkofler | Process for reducing slime formation in systems with a water cycle and application of the process |
-
1991
- 1991-01-28 ES ES91101061T patent/ES2056500T3/en not_active Expired - Lifetime
- 1991-01-28 DK DK91101061.9T patent/DK0496905T3/en active
- 1991-01-28 AT AT9191101061T patent/ATE105267T1/en not_active IP Right Cessation
- 1991-01-28 EP EP91101061A patent/EP0496905B1/en not_active Expired - Lifetime
- 1991-01-28 DE DE59101575T patent/DE59101575D1/en not_active Expired - Lifetime
-
1992
- 1992-01-27 FI FI920351A patent/FI104817B/en not_active IP Right Cessation
- 1992-01-27 CA CA002060073A patent/CA2060073C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0496905B1 (en) | 1994-05-04 |
| DE59101575D1 (en) | 1994-06-09 |
| FI920351A (en) | 1992-07-29 |
| FI104817B (en) | 2000-04-14 |
| DK0496905T3 (en) | 1994-11-14 |
| CA2060073A1 (en) | 1992-07-29 |
| ATE105267T1 (en) | 1994-05-15 |
| FI920351A0 (en) | 1992-01-27 |
| EP0496905A1 (en) | 1992-08-05 |
| ES2056500T3 (en) | 1994-10-01 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed | ||
| MKEC | Expiry (correction) | ||
| MKEC | Expiry (correction) |
Effective date: 20121211 |