Classifications

• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F11/00—Treatment of sludge; Devices therefor
  • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
  • C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
  • C02F11/126—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering using drum filters
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F11/00—Treatment of sludge; Devices therefor
  • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
  • C02F11/13—Treatment of sludge; Devices therefor by de-watering, drying or thickening by heating
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/26—Nature of the water, waste water, sewage or sludge to be treated from the processing of plants or parts thereof
  • C02F2103/28—Nature of the water, waste water, sewage or sludge to be treated from the processing of plants or parts thereof from the paper or cellulose industry
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F26—DRYING
  • F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
  • F26B2200/00—Drying processes and machines for solid materials characterised by the specific requirements of the drying good
  • F26B2200/18—Sludges, e.g. sewage, waste, industrial processes, cooling towers

Definitions

• the invention relates to a method and a pro ⁇ cess for treating sludge. Further, the invention relates to a product formed from the sludge. Further, the invention relates to a use of the product. BACKGROUND OF THE INVENTION
• the objectives of the invention are to dis ⁇ close a new method for treating sludges from a waste paper treatment and/or a paper mill reject and/or bio sludge and for manufacturing a new type product which can be utilized.
• the method for treating a sludge according to the present invention is characterized by what is pre ⁇ sented in claim 1.
• the product according to the present inven ⁇ tion is characterized by what is presented in claim 11.
• the use of the product according to the pre ⁇ sent invention is characterized by what is presented in claim 13.
• Fig. 1 is a flow chart illustration of a method according to one embodiment of the present in ⁇ vention in which the separation of the fractions is carried out in one separation step,
• Fig 2 is a flow chart illustration of a method according to another embodiment of the present in ⁇ vention in which the separation of the fractions is carried out in two separation steps,
• Fig 3 is a flow chart illustration of a method according to another embodiment of the present in ⁇ vention in which the separation of the fractions is carried out in three separation steps, and
• Fig 4 is a flow chart illustration of a waste paper treatment.
• a product is formed from a sludge 1 which contains reject from a waste pa ⁇ per treatment and/or a paper mill and/or a waste water treatment plant.
• the sludge 1 is treated by drying in at least one drying step 2, and at least two fractions 10, lla-c, 12, 13 are recovered from the dried sludge 3 in at least one separation step 4 so that the first fraction 10 includes at least fibers and the second fraction 11a includes at least minerals.
• a process of the present invention is presented in figure 1.
• the sludge 1 contains re- jects, such as sludges, rejects and residues, a waste paper treatment and/or a paper mill and/or a waste water treatment plant.
• the sludge 1 contains at least rejects, such as sludges, rejects and residues, from a waste paper treatment, e.g. RCF sludge.
• the sludge contains mainly rejects from a waste paper treatment, e.g. from a deinking process, such as RCF sludge.
• a typical waste paper treatment process is presented in figure 4. Fur ⁇ ther, the sludge may include rejects, such as sludges, rejects and residues, from a paper mill.
• these paper mill rejects do not include bio-sludge.
• the sludge may include rejects, such as sludges, from a waste water treatment plant, e.g. pri ⁇ mary sludge and/or bio sludge.
• the sludge may include rejects, such as sludges, rejects and resi ⁇ dues, from any paper industry process.
• the sludge may also include sludges and rejects from other processes.
• RCF sludge means any RCF reject, e.g. deinking reject, or any combination of different RCF rejects from RCF process, i.e.
• the sludge may include minerals used in paper coating, filler and printing inks, and fibers, fines, sticky materials like starch, latex and adhesive, and other inorganic components and/or small amount of other components, preferably other reject components.
• the sludge includes 50 - 90 w-% (% by weight), more preferable 60 - 80 w-%, in ⁇ organic components. In one embodiment the sludge in- eludes below 90 w-%, more preferable below 85 w-%, in ⁇ organic components.
• the sludge in ⁇ cludes over 55 w-%, more preferable over 60 w-%, inor- ganic components.
• the sludge is high solid sludge in which dry solid content can be about 50 - 70 %.
• the sludge can be dewatered to form the high solid sludge before a use as the sludge in the method of the present invention.
• the sludge may be treated in the dewatering by means of a gravitation table, disc filter and/or screw press or the like before the method of the present inven ⁇ tion.
• the sludge includes 50 -
• the sludge includes 80 - 100 w-% rejects from a waste paper treatment. In one embodiment the sludge includes over 80 w-%, preferably over 90 w-% rejects from a waste paper treatment. In one embodiment the sludge contain over 80 w-% RCF sludge, in one embodiment over 90 w-% RCF sludge. In one embodiment the sludge includes 80 - 100 w-% RCF sludge.
• the sludge includes below 50 w-%, preferably below 40 w-%, more preferable below 30 w-% and most preferable below 20 w-% rejects from a paper mill, in one embodiment below 10 w-% rejects from a paper mill.
• the sludge in ⁇ cludes below 50 w-%, preferably below 40 w-%, more preferable below 30 w-% and most preferable below 20 w-% sludges from a waste water treatment plant, in one embodiment below 10 w-% sludges from a waste water treatment plant.
• the sludge includes below 50 w-%, preferably below 40 w-% and more prefer- able below 30 w-%, rejects from a paper mill and sludges from a waste water treatment plant.
• the sludge includes below 20 w-% rejects from a paper mill and sludges from a waste water treatment plant.
• the sludge includes 50 - 100 w-% rejects from a paper mill.
• the sludge includes below 50 w-% rejects from a waste pa ⁇ per treatment. The sludge is fed to the process.
• a technical effect of the invention is that different rejects from a waste paper treatment and/or a paper mill and/or waste water treatment plant can be utilized.
• An additional technical effect of the inven ⁇ tion is that different fractions are easy to separate from the sludge. Further, the separation efficiency of the different fractions is good. The materials of the fractions can be reused and then environmental load decreases.
• the drying can be carried out in one or more drying steps 2. In preferred embodiment the drying is made in one step. In one embodiment the drying is made in at least two drying steps. Preferably, after the drying moisture content of the dried sludge is below 15 %, more preferable below 10 % and most preferable below 5 % or most preferable below 4 % or most preferable below 3 % or most preferable below 2 % or most preferable below 1 %.
• the drying can be made by means of drying de ⁇ vice selected from the group: indirect dryer, direct sludge dryer, paddle dryer, flash dryer, fluidized bed dryer, cyclone dryer, air dryer, air grinder, rotor mill, centrifugal mill, air turbulence mill, air tur- bulence dryer and other suitable dryers and other suitable mills, and their combinations.
• drying is carried out by such air dryer or air grinder in which particles can be separated one from the oth ⁇ er.
• the drying is carried out by a rotor mill. When the drying is made in the rotor mill so then thermal and mechanical drying can be made at the same time which ensures the fiberizing and drying of material during the drying. Then no extra fiberizing steps are needed.
• a drying device can also act as a grinder.
• a grinder can act as a drying device.
• fiberizing is made simultaneously than the drying.
• low temperature can be used in the drying.
• the sludge is dried at temperature between 25 to 170 ° C, preferably between 25 to 100 ° C or between 100 to 170 ° C, more preferable between 25 to 60 ° C or between 50 to 100 ° C or between 100 to 160 ° C. It is important that temperature is selected so that organic components are not damaged. Further, res ⁇ idue heat, e.g. from a mill, can be used in the pro- cess of the present invention.
• the dried sludge can be crushed before the separation of the fractions.
• the method comprises additional step for separating or disintegrating agglomerates after the drying of the sludge.
• the disintegration of the ag ⁇ glomerates can be made any disintegrating or crushing device known per se.
• the sludge can be crushed in the connection with the dry- ing. In one embodiment agglomerates are broken during the drying, and then separate crushing steps are not needed .
• the method comprises pre- treatment step for crushing the sludge before the dry- ing.
• the crushing can be made by any crushing device known per se.
• moisture content of the dried sludge is analyzed, e.g. by an on-line measure ⁇ ment or by a laboratory analysis, after the drying.
• the drying can be adjusted based on measurement re ⁇ sults .
• dry content of the sludge may be increased so that DS increases from about 40 - 70 % to 80 - 99 % during the drying.
• DS means dry solids content.
• the sludge is fed rapidly from the drying to the separation step, for example in a closed process.
• separation means any separa- tion, fractionation and/or screening.
• the first fraction 10 is preferably a fiber fraction.
• the first fraction may also include other components, such as minerals, adhesives, latex, starch and/or other components.
• the fiber fraction includes fibers and minerals.
• the first fraction includes below 40 w-%, preferably below 30 w-%, more preferable below 25 w-%, min ⁇ erals .
• the se- cond fraction lla-c includes at least minerals, but it may include other substances, such as fines, latex, adhesives, starch and/or other components.
• the second fraction 11a contains minerals and fines.
• the second fraction may also include other com- ponents.
• the second fraction in ⁇ cludes below 50 w-%, preferably below 40 w-%, more preferable below 30 w-%, most preferable below 25 w-%, fines.
• the second fraction includes over 50 w-% fines, and then the second fraction may be utilized in the burning.
• the recov ⁇ ering of fractions is carried out in one separation step 4.
• the fractions are recovered in more than one separation steps 4,5,6.
• the fractions are recovered in two separation steps 4,5.
• the fractions are recov ⁇ ered in three separation steps 4,5,6.
• the fractions are recovered in more than three separa ⁇ tion steps.
• the first fraction 10 is firstly separated from the dried sludge 3 before the recovering of the second fraction 11a.
• the first fraction compris ⁇ ing fiber fraction is separated from the second frac ⁇ tion comprising smaller fraction after a rotor mill.
• the smaller fraction consists of minerals, which are used e.g. in paper coating, and fines, filler, print ⁇ ing inks, binders, such as latex and starch, and other smaller particle and their agglomerates which pass a sieve .
• three fractions are recovered from the dried sludge 3 so that the first fraction 10 includes fibers, the second frac ⁇ tion lib includes minerals and the third fraction 12 includes fines.
• the fractions 10, lib, 12 may also in ⁇ clude other components.
• the first fraction 10 is firstly separated from the dried sludge 3, after that the third fraction 12 is separated from the dried sludge 3 and finally the second fraction lib is recovered.
• the recovering of frac ⁇ tions is carried out in two separation steps 4, 5.
• a process of the present invention is presented in fig ⁇ ure 2.
• the second fraction lib con ⁇ sisting of minerals is divided into two or more mineral fractions which may include same or different mineral components.
• the each mineral fraction may include one mineral component or more than one mineral component, e.g. CaCo 3 , clay, talc or similar.
• the mineral fractions are separated based on mineral components, e.g. mineral component A and mineral compo- nent B.
• the mineral fractions are separated based on particle size, e.g. small particles and big particles.
• the mineral fractions may include other components.
• more than three fractions are recovered from the dried sludge 3.
• four fractions are recovered so that the first fraction 10 includes fibers, the second fraction 11c includes minerals and the third fraction 12 includes fines and the fourth fraction 13 includes minerals.
• the fractions 10, 11c, 12, 13 may also include other components.
• the first fraction 10 is firstly sepa- rated from the dried sludge 3, after that the third fraction 12 is separated from the dried sludge 3 and finally the second 11c and fourth 13 fractions are sep ⁇ arated and recovered.
• the recovering of fractions is carried out in three separation steps 4, 5, 6.
• a process of the present invention is pre ⁇ sented in figure 3.
• the dried sludge comprises a residue.
• the residue may contain fibers, minerals, stickies, inks, fines and the like.
• the fractions can be recovered totally to be utilized from the dried sludge without residue.
• the separation can be made by means of separa ⁇ tion technique and/or device selected from the group dry separation, wet separation, mechanical screening, vibrating screen, oscillation screen, rotary classifier, air classifier, centrifuge, separation based on density differences, separation based on particle size and their combinations. Also other separation methods can be used.
• the separation device is suit ⁇ able for screening the dried sludge into desired frac ⁇ tions .
• process conditions in the separation are analyzed, e.g. by on-line measurements or by laboratory analysis after the separation.
• the separation step can be adjusted and/or controlled based on measurement results.
• the frac ⁇ tion 10, lla-b and/or 12 is pelletized after the sepa- ration in order to form a pelletized product 15,16, such as pellets 15, 16.
• the first fraction 10 is pelletized.
• the third fraction 12 is pelletized.
• the second fraction lla-c is pelletized.
• pellet means any pellet, granulate, briquette, agglomerate and their combina- tions.
• the pelletizing can be carried out by means of any suitable pelletizing technique and/or apparatus known to a man skilled in the art, e.g. pelletizing, granulation and their combinations.
• the pelletized product can be used easily as fuel for producing ener- gy. Further, the pelletized product is easy and cost- effective to transport and/or store. Further, the pre- servability of the pelletized product is good.
• the frac ⁇ tion is briquetted after the separation in order to form a briquetted product, such as briquettes.
• the first fraction is briquetted.
• the third fraction is briquetted.
• the second fraction is briquetted.
• the process according to the invention can be a continuous and/or batch process.
• the product formed is selected from the group: a prod ⁇ uct comprising fibers, a product comprising fines, a product comprising minerals, a product comprising de- sired mineral component or product comprising minerals and fines.
• a prod ⁇ uct comprising fibers
• a product comprising fines comprising fibers
• a product comprising minerals comprising minerals
• a product comprising de- sired mineral component or product comprising minerals and fines are examples of each product formed.
• Each product may include also other compo ⁇ nents .
• the product of the invention is used as a ma ⁇ terial component in a final product.
• the product can be used in different embodiments.
• the product according to the invention can be used as a material component in composites and papers.
• the product, specially the fiber containing fraction or the second fraction including fines, ac- cording to the present invention can be used as fuel for producing energy.
• different fractions can be recovered and they can be utilized.
• the present invention provides products with good or adequate quality.
• the method of the present invention offers a possibility to prepare the products from the sludge cost-effectively and energy-effectively .
• the present invention provides an industrially applicable, simple and affordable way of treating sludges and making the products from sludges and rejects.
• the method accord- ing to the present invention is easy and simple to re ⁇ alize as a production process.
• the method according to the present invention is suitable for use in the manufacture of the differ ⁇ ent products from different sludges containing organic and/or inorganic components.
• a product is formed from a high solid sludge 1 com- prising over 80 % RCF reject from a waste paper treat ⁇ ment and below 20 % paper mill sludge.
• the sludge 1 is fed to the process, and the sludge is dried in the drying step 2, and desired fractions are recovered in the separation steps 4 and 5.
• the drying is made in one drying step 2 in order to form the dried sludge 3.
• a moisture content of the dried sludge 3 is below 10 %.
• DS may be in ⁇ creased from about 40 - 70 % to 95 - 99 %
• the first separation step 4 the first fraction 10 containing mainly fibers is separated from the dried sludge 3.
• the first fraction product 10 is pelletized in the pelletizing step 8 to form the first product pellets 15.
• the third fraction 12 containing mainly fines is separated from the second fraction lib containing mainly minerals.
• the third fraction product 12 is pelletized in the pelletizing step 9 to form the second product pel ⁇ lets 16.
• a product is formed from a high solid sludge 1 com ⁇ prising about 80 % RCF reject from a waste paper treatment and about 10 % reject from a paper mill and about 10 % bio-sludge from a waste water treatment plant .
• the sludge 1 is fed to the process, and the sludge is dried in the drying step 2, and desired fractions are recovered in the separation steps 4, 5 and 6.
• the drying is made in one drying step 2 in order to form the dried sludge 3.
• a moisture content of the dried sludge 3 is below 10 %.
• DS may be in ⁇ creased from about 40 - 70 % to 95 - 99 %
• the first separation step 4 the first fraction 10 containing mainly fibers is separated from the dried sludge 3.
• the first fraction product 10 is pelletized in the pelletizing step 8 to form the first product pellets 15.
• the third fraction 12 containing mainly fines is separated from the second fraction lib containing mainly minerals.
• the third fraction product 12 is pelletized in the pelletizing step 9 to form the second product pel ⁇ lets 16.
• the second fraction lib containing mainly mineral components is divided into two fractions so that the second fraction 11c in- eludes mainly mineral component A and the fourth frac ⁇ tion 13 includes mainly mineral component B.
• a product was formed from a high solid sludge 1 com ⁇ prising over 80 % RCF reject from a waste paper treatment and below 20 % paper mill sludge.
• the sludge 1 included about 30 w-% component containing fibers, fines and stickies, about 54 w-% calcium, about 14 w-% clay and about 2 w-% other inorganic components.
• the stickies contained latex, starch and adhesives.
• the sludge 1 was fed to the process, and the sludge was dried in the one drying step 2 in which the sludge was dried by rotor mill. Thermal and mechanical drying is made at the same time in the rotor mill which ensures the fiberizing and drying of material during the drying.
• the first and second fractions were separated by vibration screen so that the first fraction includ- ed mainly fibers and the second fraction included mainly minerals and fines.
• the sizes of screens were 0.2 mm and 1.9 mm.
• the second fraction contained under 0.2 mm material components including minerals, fines and stickies.
• the first fraction contained mate ⁇ rial components between 0.2 - 1.9 mm and over 1.9 mm including fibers, and a little minerals, fines and stickies .
• the products according to the present inven ⁇ tion are suitable in different embodiments to be used in different final products.
• the method according to the present invention is suitable in different embodi ⁇ ments to be used for manufacturing the most different kinds of products.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Life Sciences & Earth Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Treatment Of Sludge (AREA)
• Processing Of Solid Wastes (AREA)

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• 2012
  • 2012-06-26 FI FI20125724A patent/FI126056B/en not_active IP Right Cessation
• 2013
  • 2013-06-26 EP EP13810049.0A patent/EP2864257A4/de not_active Withdrawn
  • 2013-06-26 WO PCT/FI2013/050704 patent/WO2014001641A1/en active Application Filing

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