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WO2017178849A1 - Processus continu destiné à la production de pâte de cellulose - Google Patents

Processus continu destiné à la production de pâte de cellulose Download PDF

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Publication number
WO2017178849A1
WO2017178849A1 PCT/HR2016/000014 HR2016000014W WO2017178849A1 WO 2017178849 A1 WO2017178849 A1 WO 2017178849A1 HR 2016000014 W HR2016000014 W HR 2016000014W WO 2017178849 A1 WO2017178849 A1 WO 2017178849A1
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WIPO (PCT)
Prior art keywords
linne
cellulose pulp
bleaching
cellulose
continuous
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Ceased
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PCT/HR2016/000014
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English (en)
Inventor
Marinko Mikulic
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Individual
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Individual
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Priority to DK16722693.5T priority Critical patent/DK3443159T3/da
Priority to HRP20200981TT priority patent/HRP20200981T1/hr
Priority to ES16722693T priority patent/ES2806475T3/es
Priority to PCT/HR2016/000014 priority patent/WO2017178849A1/fr
Priority to RS20200820A priority patent/RS60519B1/sr
Priority to EP16722693.5A priority patent/EP3443159B1/fr
Priority to PL16722693T priority patent/PL3443159T3/pl
Publication of WO2017178849A1 publication Critical patent/WO2017178849A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C3/00—Pulping cellulose-containing materials
    • D21C3/02—Pulping cellulose-containing materials with inorganic bases or alkaline reacting compounds, e.g. sulfate processes
    • 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
    • D21C11/0007—Recovery of by-products, i.e. compounds other than those necessary for pulping, for multiple uses or not otherwise provided for
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/1063—Bleaching ; Apparatus therefor with compounds not otherwise provided for, e.g. activated gases
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/16—Bleaching ; Apparatus therefor with per compounds
    • D21C9/163—Bleaching ; Apparatus therefor with per compounds with peroxides
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
    • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
    • D21H11/12—Pulp from non-woody plants or crops, e.g. cotton, flax, straw, bagasse

Definitions

  • the invention is related to an improved continuous process for production of cellulose pulp of very high whiteness, >90%, and lignin content ⁇ 5% w/w, from comminuted grass-like feedstock such as miscanthus (Miscanthus x giganteus, Andersson) .
  • the main technical problem, solved by the present invention is formation of the novel process for production of cellulose pulp having high whiteness, from a grass-like feedstock in an effective way.
  • This effective way is achieved by using as little as possible of inexpensive environmentally-acceptable chemicals and under as mild as possible digestion and bleaching conditions. Also, such process should ensure maximal preservation of natural cellulose fibers from the starting feedstock.
  • the first technical problem solved with the disclosed invention is to use milder and optimized chemical reagents during digestion and bleaching steps and very high whiteness, higher than 90%, thus avoiding harsh and high energy-consuming manufacturing conditions, dangerous and sulphur-based chemicals, and environment pollution with waste waters containing residues of all these processing chemicals.
  • the technical problem solved with the disclosed invention is to find a solution within the frame of "green"-chemical technology, characterized by:
  • this is the first eco-friendly process for cellulose pulp manufacturing that operates at such mild digestion conditions, with very low water consumption, low energy consumption, which can produce cellulose of very high whiteness, higher than 90%, with ⁇ 5% w/w of lignin, which can yield top-quality paper of excellent mechanical properties.
  • the process according to this invention does operate well only when grass-like feedstock is employed.
  • miscanthus (Miscanthus x giganteus, Andersson) is one of most suitable grass-like feedstock for such use; see references 1 and 2:
  • sulphur-containing chemicals sodium carbonate ( a 2 C03 ) and sodium sulfite ( a2S03 ) , magnesium hydroxide [Mg(OH)2] and magnesium sulfite ( gS0 3 ) , ammonium hydroxide (NH 4 OH) and ammonium sulfite [(NH ⁇ SC ], calcium hydrogensulfite [Ca(HS03)2], magnesium hydrogensulfite [Mg(HS03)2]/ sodium hydroxide (NaOH) , sodium sulphide ( a2S) and sodium sulphate (Na 2 S0 4 ) ;
  • non-sulphur containing chemicals sodium carbonate (Na2C0 3 ) , sodium hydroxide (NaOH) ;
  • Such solution of digesting chemicals is also known as black liquor", representing either fresh or regenerated solution of digestion chemicals.
  • the white liquor helps to remove non-cellulosic materials, which are thus dissolved in the solution, leaving relatively pure cellulose fibers suspended in this liquid phase.
  • Cooked feedstock with removed non-cellulosic materials i.e. a perennialpulp
  • a bathpulp is, at the end of digestion, suspended in used solution, which contains various chemical forms of non-cellulosic plant ingredients and remains of digestion chemicals.
  • This aqueous phase is called the strictlyblack liquor".
  • the pulp after the digestion is a suspension of essentially pure cellulose fibers in the black liquor .
  • the digestion steps can be performed with microwave (MW) assisted heating.
  • MW microwave
  • Zhu and co-workers described the pretreatment process of miscanthus /Miscanthus x giganteus, Andersson/ with sodium hydroxide (NaOH) solution at very high temperatures (130-200 °C) at elevated pressures during 20 minutes under MW heating.
  • NaOH sodium hydroxide
  • Such pre- treated miscanthus further gave much better yield in sulphuric acid (H 2 SO4) -catalysed hydrolysis to glucose as a feedstock to fermentation into bioethanol; see reference 4:
  • McQueen-Mason Microwave assisted chemical pretreatment of Miscanthus under different temperature regimes, Sustain. Chem. Process 3 (2015) DOI : 10.1186/s40508-015-0041-6.
  • the bleaching is another important key step in manufacturing of cellulose of high whiteness is the bleaching step.
  • the most common systems for cellulose bleaching are those based on chlorine-containing systems, e.g. sodium hypochlorite (NaOCl), or hydrogen peroxide ( H2O2 ) -based systems, the latter one being preferred .
  • sodium silicate (xNa20»ySi0 2 ) solution is used as a hydrogen peroxide-stabilizer; see reference 5 :
  • H2O2 hydrogen peroxide
  • NaOH sodium hydroxide
  • the present invention is also based on hydrogen peroxide ( H2O2 ) - bleaching, but the main, crucial, and advantageous difference is in the use of a combination of ⁇ 2 0 ⁇ and sodium silicate solution (x a 2 0«ySi02> , essentially without the use of sodium hydroxide (NaOH) as a co-reagent which, in reaction with H2O2 , generates equilibrium concentration of hydroperoxide anions (HOO-) as actual oxidizing species .
  • H2O2 hydrogen peroxide
  • H2O2 hydrogen peroxide
  • NaOH sodium hydroxide
  • sodium silicate solution can also be optionally employed as the stabilizer for H2O2; see reference 7:
  • one feature of the process for manufacturing of cellulose pulp of very high whiteness is certainly whether the cooking chemicals from the digestion phase is removed from the pulp or they can be retained in the pulp before the bleaching step.
  • the older processes performed removal of the black liquor which contains digesting chemicals, lignin, and other non-cellulosic byproducts .
  • Abu and co-workers disclosed a process for production of fibrous cellulose material which includes: (1) comminuting of plant material, (2) mixing it with 0.5-1% aqueous sodium hydroxide (NaOH) solution, (3) sieving, (4) passing thus obtained material from extruder wherein the material is mixed with hydrogen peroxide (H 2 0 2 ) at 120-150 °C at 20 bar, and (5) discharging out from the extruder and washing with water; see reference 8:
  • the present invention is also characterized by one of key details that it does not involve washing out of remaining cooking chemicals after digestion phase, but directly undergoes to disperging and bleaching steps.
  • Mikulic disclosed a continuous process for production of cellulose pulp from grass-like feedstock such as miscanthus ⁇ Miscanthus x giganteus, Andersson) , using a vertical digester with smooth internal walls without any screen or mixing element inside, by the use of very dilute cooking chemicals, sodium hydroxide (NaOH) and sodium chloride (NaCl) or sodium sulphite (Na2S0 3 ) , with the following average composition of digesting suspension:
  • digesting process is heated by conventional means, either through direct heating of the digester or with heating medium; see reference 9.
  • this process is also based on subsequent processing of cooked pulp within the screening and fractionation device which isolate a good cellulose pulp fraction and separate the improper one.
  • the later is further subjected to pulp milling in one or more suitable pulp mills yielding the proper cellulose pulp.
  • pulp milling in one or more suitable pulp mills yielding the proper cellulose pulp.
  • This can be further optionally bleached with conventional bleaching chemicals to yield high quality cellulose suitable for paper production.
  • the digestion (a) and bleaching (c) processes can be performed by microwave (MW) -assisted heating with comparable good results within significantly shorter period of time for each step.
  • steps (a) -(c) results in very high quality cellulose pulp of very high whiteness, >90%, with ⁇ 5% w/w of lignin, which cannot be produced by the process disclosed in the reference 9.
  • the process from this invention uses roughly similar electrolytic reactor for removal of lignin and other by-products and for parallel regeneration of cooking chemicals, NaOH + NaCl solution (white liquor) , but the main and crucial difference is in the fact that the electrolytic process in this invention works with the black liquor solution comprising dilute sodium lignin and sodium chloride (NaCl) .
  • the black liquor solution from this invention is of better conductance due to sodium chloride presence, whilst the process from reference 10 is based on processing sole sodium lignin from Organosolv technology for cellulose manufacturing.
  • the process from the present invention provides very high quality cellulose of very high whiteness, >90%, at high yield, at very low water and energy consumption.
  • the technology for production of cellulose pulp from grass-like feedstock according to this invention represents a novel and inventive technology, as is disclosed in the detailed description of the invention.
  • the present invention discloses a continuous process for production of cellulose pulp of very high whiteness from grass-like plant feedstock.
  • the process comprising the steps of:
  • step (ii) continuous digestion of a grass-like dust-free plant feedstock prepared in step (i) in a continuous digester (1) formed as a longitudinal column internally equipped with worm screw conveyor and a heating unit; where grass-like plant feedstock is continuously fed directly on the top of the said digester via conveyor (4);
  • the continuous bleaching reactor (6) which is, analogously to the digester (1), formed as a longitudinal column internally equipped with worm screw conveyor and a heating unit;
  • bleaching chemicals selected from the group comprising:
  • the continuous process for production of cellulose pulp according to the present invention optionally further involves the following manufacturing steps :
  • step (ix) screening and fractionation, where diluted suspension from the step (vii) is processed through a screening and fractionation device (22) equipped with 0.1-0.5 mm sieve, yielding two fractions;
  • the cooking chemicals for the digestion step (ii) are introduced as a mixture of concentrated aqueous solutions of 20-50% w/w NaOH and 10-30% w/w of NaCl .
  • the continuous digestion phase (ii) is preferably carried out at 90- 100 °C.
  • the bleaching chemicals for the bleaching step (iii) are introduced to the continuous bleaching reactor (6) in the form of concentrated aqueous solutions of 30-45% w/w sodium silicate (xNa20»ySiC>2) ; and 20-40% w/w of hydrogen peroxide (H2O2) .
  • the continuous bleaching process is preferably performed at 85-100 °C.
  • the continuous process for production of cellulose pulp according to the present invention can be alternatively carried out by the use of microwave (MW) -assisted heating.
  • the heating units in the continuous digester (1) and/or continuous bleaching reactor (6) are microwave (MW) -generating magnetrons.
  • the grass-like feedstock that can be processed by the process of this invention includes the stems of plant species selected from the group of: wheat (Triticum vulgare, Linne) ; rice (Oryza sativa, Linne) ; barley (Horedum vulgare, Linne) ; oat (Avena sativa, Linne) ; flax (Linum usitatissimum, Linne); maize (Zea mays, Linne); millets: proso millet (Panicum miliaceum, Linne) , pearl millet (Pennisetum glaucum, Linne) , browntop millet (Panicum ramosum, Linne) , and barnyard (Echinochloa fru entaceae, Linne) ; triticale (x Triticosecale, Wittm.
  • wheat Triticum vulgare, Linne
  • rice Oryza sativa, Linne
  • barley Horedum vulgare, Linne
  • the grass-like feedstock is miscanthus (Miscanthus x giganteus, Andersson) .
  • Figure 1 - shows a block diagram of the process for production of cellulose pulp of very high whiteness from comminuted grass-like feedstock according to the invention; key steps are: continuous digestion, disperging, continuous bleaching, optional disperging, dewatering which removes the black liquor, and washing of resulting pulp yielding white cellulose pulp.
  • the black liquor is optionally partially evaporated and further processed by electrolysis, isolating lignin and other non-cellulosic by-products, and to regenerate the cooking chemicals solution.
  • microwave (MW) -heating can be optionally employed; marked with intermittent line.
  • Figure 2 - shows a block diagram of the process for production of cellulose pulp of very high whiteness according to the invention; with . emphasis to additional steps: screening and fractionation and milling of cellulose pulp, which are performing optionally.
  • microwave (MW) -heating can be optionally employed; marked with intermittent line.
  • the invention is related to an improved continuous process for production of cellulose pulp of very high whiteness, higher than 90%, of 10% w/w dry matter, and lignin content ⁇ 5% w/w, from comminuted grass-like feedstock such as miscanthus (Miscanthus x giganteus, Andersson) .
  • Such grass-like feedstock usually contains roughly 30-45% w/w of cellulose with 15-32% w/w of lignin; see literature reference 11:
  • the process is performed in a continuous manner through several manufacturing phases, as shown in Figures 1 and 2 :
  • the feedstock is prepared by comminuting, to produce a material with longitudinal size distributed from 5-30 mm and diameter of 0.1-2 mm.
  • Comminution of the starting grass-like material is carried out by conventional devices for comminuting or supplied directly from the fields, if the crops were collected by suitable combine harvester equipped with adequate chopping device yielding the plant material of above-stated particles dimensions.
  • the comminution should be performed in a mild manner yielding fibrous material predominantly comminuted along the fibers, in order to preserve them.
  • the comminuted material is subjected to dedusting by removal of fine, dusty, non-fibrous plant material, which would otherwise reduce the quality of resulting cellulose pulp. This is done by suitable fan which produces a strong air circulation that enable blowing away of fine light particles.
  • collected fine non-fibrous dust can be used in the process as a fuel in energy production or as raw material in manufacturing of xylan .
  • Continuous digestion or cooking of a grass-like dust-free plant feedstock prepared in step (i) is performed in a continuous digester (1) formed as a longitudinal column, internally equipped with worm screw conveyor and a heating unit, where grass-like plant feedstock is continuously fed directly on the top of the said digester via conveyor (4) .
  • the chemicals for digestion sodium hydroxide (NaOH) and sodium chloride (NaCl) , and fresh water and/or regenerated white liquor, are introduced continuously on the top of said digester (1) ; maintaining the digestion temperature from 70-120 °C and average composition of thus formed suspension during said continuous digestion is keeping within the following ranges:
  • the continuous digestion process according to this invention is performed by introduction of cooking chemicals as concentrated aqueous solutions of 20-50% w/w sodium hydroxide (NaOH) and 10-30% w/w of sodium chloride (NaCl) .
  • sodium hydroxide and sodium chloride solutions can be added as a previously prepared mixture.
  • the preferred range is 90-100 °C.
  • the cooked cellulose pulp is continuously, by equal rate as being feedstock fed into the digester (1), discharged from the said digester (1) , via conveyor, directly into disperger (5) to perform disperging phase (iii) , where the suspended cellulose pulp is subjected to main disperging, yielding finely disperged/separated cellulose fibers.
  • disperger (5) in this phase of the process is absolutely essential for high quality cellulose pulp.
  • the bleaching phase (iv) previously disperged cellulose pulp is continuously fed into the continuous bleaching reactor (6) which is, analogously to the digester (1) , formed as a longitudinal column internally equipped with worm screw conveyor and a heating unit.
  • the bleaching is carried out with a solution of bleaching chemicals selected from the group comprising:
  • the continuous bleaching process according to the present invention is carrier out at temperatures from 85-100 °C.
  • bleaching chemicals are preferably introduced into the continuous bleaching reactor (6) separately in the form of concentrated aqueous solutions of 20-40% w/w of hydrogen peroxide (H 2 0 2 ) and 30-45% w/w of sodium silicate (xNa 2 OySi0 2 ) .
  • the cellulose pulp can be additionally subjected to the treatment with optical brighteners in the manner that is well known in the art.
  • optical brightener is Tinopal ABP-A liquid (from CIBA Specialty Chemicals Corporation) , which contains 22-24% dry matter of fluorescent brightener from triazinyl stilbene-type .
  • Such products are typically added at 0.25-0.50% w/w dosage to the dry matter content of cellulose pulp.
  • This treatment can be performed in order to further increase whiteness of the final cellulose when the highest possible, top- quality products are manufactured.
  • the suspension of thus obtained bleached cellulose pulp, discharged from the bleaching step (iv) , is optionally further subjected to additional disperging (phase v) , through the disperger (8) .
  • the cellulose pulp is transferred into the dewaterer (9), where the bleached and eventually additionally disperged cellulose pulp is dewatered, separated from the black liquor yielding:
  • the black liquor from the dewatering step (vi) is transported via manifold (10) into the electrolytic reactor (19) for regeneration of cooking chemicals solution and isolation of lignin and other non- cellulosic by-products.
  • black liquor includes the process effluent from both digestion (ii) and bleaching (iv) phases; it contains residual sodium hydroxide (NaOH) , sodium chloride (NaCl) , solubilized lignin, other non-cellulosic by-products, and eventually traces of remaining hydrogen peroxide.
  • the black liquor can be partially concentrated in evaporator (16) to yield regenerated water which is transported back to the washing step (vii) and concentrated back liquor which goes to the electrolytic reactor (19) via manifold (18) .
  • the bleached cellulose pulp is additionally washed (phase vii) in the washing vessel (12) with additional fresh water, which is introduced through the manifold (13), giving:
  • washing process water includes the process effluent from the continuous washing process (vii phase) ; it contains residuals of the black liquor that always remains adsorbed on cellulose fibers within the pulp that comes out from the dewatering phase (vi) . Therefore, the washing process water is more likely as very diluted black liquor.
  • optimal degree of the black liquor concentration is" preferably up to 0.9- 1.05 w/w of sodium (as Na + ) in the concentrated black liquor that enters the electrolytic reactor (19) .
  • evaporator involves not only classical evaporation devices which are based on either distillation or vacuum distillation, but also all other means of water removal from the aqueous solutions, e.g. by reverse osmosis, ion-exchange process, electrodeionization, etc.
  • either original (“as is”) combined black liquor (a) or concentrated black liquor (b) is subjected to electrolysis with direct electric current (DC) between two electrodes, at electric potential of 3-30 V, and electric current density of 1-10 A/dm 2 , at 10-95 °C, wherein the lignin and byproducts are separated on the top of the electrolyte solution in the anode compartment, and continuously removed from the electrolytic reactor .
  • DC direct electric current
  • Electrodes, cathode and anode are made from suitable electro- conductive materials resistant to highly reactive chemicals formed in their compartments, e.g. to NaOH of high pH value.
  • suitable materials are: metals such as carbon steel or stainless steels, graphite, magnetite, etc.
  • cathode is made from a carbon steel, e.g. of type ⁇ 36, or stainless steels, e.g. of types AISI 304, 316, 321, whilst anode is formed from graphite or magnetite.
  • Electrodes can be formed in various shapes, of which plates and wire mesh are preferred.
  • Diaphragm is made from materials selected from the group comprising: asbestos, rock wool (stone wool) , Portland cement, aluminium oxide
  • AI2O3 titanium dioxide (T1O2) , zirconium dioxide ( ⁇ 3 ⁇ 4) , polyethylene (PE) , polyetersulfone (PES) , polyvinyl chloride (PVC) , polytetrafluoroethylene (PTFE; Teflon R ) , polyvinylidene fluoride
  • PVDF sulfonated polytetrafluoroethylene
  • Nafion R sulfonated polytetrafluoroethylene
  • clay and sodium silicate from combinations of said materials, or from other suitable chemically resistant materials.
  • the electrolytic lignin removal and white liquor regeneration is conducted at electric potential of 3-10 V and electric current density of 3-7 A/dm 2 .
  • the alkaline black liquor from the cellulose-manufacturing process is introduced into the anode compartment.
  • the lignin and other by-products are separated on the top of the electrolyte solution from the anode ( + ) compartment, and are removed out from the process by conventional mechanic means, via conveyor or so. Separation of lignin within the anode (+) compartment is facilitated by the evolution of gaseous oxygen (O2) as a by-product of accompanied water electrolysis.
  • O2 gaseous oxygen
  • the resulting electrolyte solution with regenerated sodium hydroxide (NaOH) and sodium chloride (NaCl) solution, representing the white liquor, is regenerated back to the digesting/cooking process, via manifold (21) , to the continuous digester (1) , closing the whole cellulose-manufacturing process .
  • the term "white liquor” includes the process effluent from the phase (viii) of the continuous electrolytic regeneration of cooking chemicals, NaOH and NaCl, solution. It contains mainly diluted sodium hydroxide and sodium chloride, with trace amounts of lignin and other non-cellulosics originating from the black liquor.
  • the lignin is separating at the top of the electrolyte solution in the cathode compartment and is continuously removing via conventional conveyor type transporter (20) .
  • electrolytic reactor in the present invention includes single or a battery (series) of several or large number of combined electrolytic cells. This depends on the capacity or scale of cellulose pulp manufacturing by using the process according to this invention. For instance, larger manufacturing facility may comprise a series of 10-100 electrolytic cells. In the case of high tonnage manufacturing facility, such "electrolytic reactor” can comprise several hundreds of such electrolytic cells.
  • the process for production of cellulose pulp, of very high whiteness further comprises the manufacturing steps of screening, fractionation, and milling.
  • the diluted suspension from the step (viii) is further processed through a screening and fractionation device (22) equipped with 0.1-0.5 mm sieve, yielding two fractions;
  • a continuous process for production of cellulose pulp, of very high whiteness, according to the present invention can be performed by employing the microwave (MW) heating in the continuous digester (1) and/or continuous bleaching reactor (6) in the manner that is known in the art.
  • the heating units in the continuous digester (1) and/or continuous bleaching reactor (6) are microwave (MW) -generating magnetrons, or series of the magnetrons.
  • the grass-like feedstock that can be used as starting raw material for the process of the present invention includes stems of plant species selected from the group of: wheat (Triticum vulgare, Linne) rice (Oryza sativa, Linne) ; barley ⁇ Horedum vulgare, Linne) ; oat (Avena sativa, Linne) ; flax ⁇ Linum usitatissimum, Linne) ; maize (Zea mays, Linne); millets: proso millet (Panicum miliaceum, Linne), pearl millet (Pennisetum glaucum, Linne), browntop millet (Panicum ramosum, Linne) , and barnyard (Echinochloa frumentaceae, Linne) ; triticale (x Triticosecale, Wittm.
  • the content of lignin in the cellulose pulp is generally ⁇ 5% w/w, calculated on dry matter, as this ensure a good mechanical properties of resulting paper.
  • n.a. not analyzed.
  • Eventual changes of the process parameters can result in some further improvement of key quality parameters of resulting cellulose, but such changes are considered to be within the scope of this invention.
  • the present invention is obviously industrial applicable. Furthermore, the process from the present invention is characterized by the following key features:
  • continuous bleaching reactor essentially the same as continuous digester
  • dewaterer - manifold for transport of the black liquor from dewaterer to the electrolytic reactor for lignin removal, or optionally, to the evaporator 16_

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  • Wood Science & Technology (AREA)
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Abstract

La présente invention concerne un processus continu destiné à la production de pâte de cellulose à blancheur très élevée à partir de matière première végétale de type herbe appropriée pour la fabrication de papier. Le processus comprend les étapes suivantes : préparation de la matière première végétale de type herbe par fragmentation ; dépoussiérage ; digestion continue avec des concentrations optimisées de NaOH et de NaCl ; dispersion ; blanchiment continu avec des concentrations optimisées de H2O2 et de silicate de sodium sans l'utilisation de NaOH ; dispersion facultative ; déshydratation pour éliminer la liqueur noire ; et lavage, pour obtenir une pâte de cellulose finale à blancheur très élevée, > 90 %, appropriée pour la fabrication de feuilles de cellulose ou de papier. Le processus comprend en outre l'élimination électrolytique intégrée de lignine et d'autres sous-produits, accompagnée de la régénération de solution de produit chimique de cuisson, ce qui permet un cycle de matériaux de traitement complètement fermé. Dans un mode de réalisation de l'invention, le chauffage des étapes de digestion et de blanchiment peut être éventuellement effectué par chauffage par micro-ondes (MW). La matière première de type herbe préférée pour le processus est le miscanthus (Miscanthus x giganteus, Andersson).
PCT/HR2016/000014 2016-04-15 2016-04-15 Processus continu destiné à la production de pâte de cellulose Ceased WO2017178849A1 (fr)

Priority Applications (7)

Application Number Priority Date Filing Date Title
DK16722693.5T DK3443159T3 (da) 2016-04-15 2016-04-15 En kontinuerlig proces til fremstilling af cellulosepulp
HRP20200981TT HRP20200981T1 (hr) 2016-04-15 2016-04-15 Kontinuirani postupak za dobivanje celulozne pulpe
ES16722693T ES2806475T3 (es) 2016-04-15 2016-04-15 Un proceso continuo para la producción de pulpa de celulosa
PCT/HR2016/000014 WO2017178849A1 (fr) 2016-04-15 2016-04-15 Processus continu destiné à la production de pâte de cellulose
RS20200820A RS60519B1 (sr) 2016-04-15 2016-04-15 Kontinuirani postupak za proizvodnju celulozne pulpe
EP16722693.5A EP3443159B1 (fr) 2016-04-15 2016-04-15 Processus continu destiné à la production de pâte de cellulose
PL16722693T PL3443159T3 (pl) 2016-04-15 2016-04-15 Ciągły sposób wytwarzania masy celulozowej

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PCT/HR2016/000014 WO2017178849A1 (fr) 2016-04-15 2016-04-15 Processus continu destiné à la production de pâte de cellulose

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WO2017178849A1 true WO2017178849A1 (fr) 2017-10-19

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WO2020160955A1 (fr) 2019-02-07 2020-08-13 MIKULIC Marinko Procédé continu de production de pâte de cellulose à partir d'une charge d'alimentation semblable à l'herbe
EP4269687A1 (fr) * 2022-04-26 2023-11-01 Wepa Professional GmbH Procédé de production de cellulose et d'extraction de lignine à partir d'une lignocellulose à partir des matières premières végétales du genre miscanthus
CN118581760A (zh) * 2024-05-22 2024-09-03 湖南骏泰新材料科技有限责任公司 一种用楠竹制备电子级绝缘浆的方法
CN118756519A (zh) * 2024-08-09 2024-10-11 山东银鹰股份有限公司 一种高甲种纤维素含量的棉浆粕的制备方法

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CA3170366A1 (fr) * 2022-08-12 2024-02-12 Sixring Inc. Optimisation de la consommation de produits chimiques dans la delignification de biomasse

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Publication number Priority date Publication date Assignee Title
WO2020160955A1 (fr) 2019-02-07 2020-08-13 MIKULIC Marinko Procédé continu de production de pâte de cellulose à partir d'une charge d'alimentation semblable à l'herbe
US20210355636A1 (en) * 2019-02-07 2021-11-18 Marinko Mikulic Continuous process for production of cellulose pulp from grass-like feedstock
US11976416B2 (en) 2019-02-07 2024-05-07 Marinko Mikulic Continuous process for production of cellulose pulp from grass-like feedstock
EP4269687A1 (fr) * 2022-04-26 2023-11-01 Wepa Professional GmbH Procédé de production de cellulose et d'extraction de lignine à partir d'une lignocellulose à partir des matières premières végétales du genre miscanthus
CN118581760A (zh) * 2024-05-22 2024-09-03 湖南骏泰新材料科技有限责任公司 一种用楠竹制备电子级绝缘浆的方法
CN118756519A (zh) * 2024-08-09 2024-10-11 山东银鹰股份有限公司 一种高甲种纤维素含量的棉浆粕的制备方法

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