WO2005064076A1

WO2005064076A1 - Closed cycle zero discharge oxidizing pulping process

Info

Publication number: WO2005064076A1
Application number: PCT/CN2003/001121
Authority: WO
Inventors: Xiuquan Mei; Laisu Xie
Original assignee: Xiuquan Mei; Laisu Xie
Priority date: 2003-12-25
Filing date: 2003-12-25
Publication date: 2005-07-14
Also published as: EP1707668A1; AU2003292884A1; CN1878909A; ZA200605196B; US20070272377A1; CN100420789C

Abstract

The present invention discloses a closed cycle zero discharge oxidizing pulping process. The process includes: (i)forming active oxygen free radicals via an electron reduction reaction with molecular oxygens in an ionic reaction unit ; (ii) transforming and separating the lignins with the active oxygen free radicals, and causing the colouring groups in the plant cell interlayers to change; (iii) obtaining the pulp. The present process basically changes traditional technology using acid , base , chlorine , anthraquinone etc. with serious pollutions. It not only excuses the cooking and bleaching, but also can use the annual plants, and also can save energy and water. It has wonderful environmental benefit, social benefits and economic efficiency.

Description

Totally closed zero-emission oxidation clean pulping process and preparation method thereof

The invention discloses a fully-closed zero-emission oxidation cleaning pulping process and a preparation method thereof, and more particularly, relates to a fully-closed self-circulation without acid, alkali, chlorine, anthraquinone, no cooking, no bleaching, Zero-emission, pollution-free clean paper pulp method. Background of the invention

There is a chronic shortage of papermaking raw materials today, not just one region but the global papermaking industry. Forests are the lungs of life on the earth. In addition to cultivating water sources, preventing soil erosion, regulating climate, etc., they can also absorb carbon dioxide and emit oxygen. Forests are not only ecological and economically valuable. However, the world is growing at an annual 700 xl 0 ^s m ² of diminishing rainforest at a rate of x per minute 50 10 ⁴ m ² reduction, if not strictly controlled to continue indiscriminate desire indiscriminate logging, 40 years later, the world population is growing, Humans will face the dilemma of no oxygen for breathing.

China Forestry Statistics Yearbook 1999 compared with 2000, the rate of forest decline: Top 10 forestry ecological projects-12.9%, natural forest protection projects-10.7%, closed forest area -6.33%, shelter forest-24.75% , Economic forest-3. 82%, timber forest-14.07%.

Non-wood cellulose raw materials are divided into plant fiber chemistry: 1. Gramineous fiber raw materials; 2. Bast fiber raw materials; 3. Seed hair fiber raw materials; 4. Leaf fiber raw materials, in which the comprehensive tritium content is 48% ~ 84 %, The length of non-wood fiber is mostly longer than that of wood fiber. Cellulose is mainly used in papermaking. Whether it is cellulose extracted from wood or grass, it can be used as the skeleton material in pulping. . Studies have confirmed that the chemical composition of non-wood raw cotton stalk fibers is similar to hardwood and softwood.

China is a large agricultural country and a large cotton-producing country, with annual resources of about 160 million metric tons (t) comparable to that of wood. During the "Tenth Five-Year Plan" period, in 2010, the planting area of key national cotton-producing areas in the country was stable at 6 million hm ² , and the annual output of high-quality cotton stalks was 34.2 million tons. 2428. 2 million tons, if the utilization rate reaches 20%, it can produce 485.6 thousand tons per year. This kind of annual resources similar to broadleaf trees has less than 1% utilization rate so far. Corn straw, wheat straw, straw (according to 2000 The three annual agricultural statistics yearbooks have reached 470 million tons. 235 million tons of non-wood fiber raw materials can be extracted. This huge amount of annual papermaking materials is now less than 5%. The United States refers to these annual resources as agriculture. Green waste is China's green annual resource. China Light Industry Press, "Pulping Process and Equipment" published in 2000, uses the sodium chlorite method to determine the comprehensive cellulose content of each raw material. The data is shown in Table 1.

Table 1 Unit: Weight%

Origin of the raw materials Synthetic cellulose Origin of the raw materials Synthetic cellulose Yukai spruce Xiaoxinganling 73. 0 Maicaohe North 71.3 Red pine Daxinganling 69. 6 Bagasse Guangdong 75. 6

,

Daguanyang Henan 81.6 Longsauria Plant West 76. 7 Green Bamboo Zhejiang 69. 5 Sorghum Stalk Hebei 66. 4 Danzhu Guangdong 67.2 Corn Stalk Hebei 84. 9 Reed Hubei 75. 4 Ningxia Cao Ningxia 79. 8 Miscanthus Hubei 76. 6 Small leaf camphor Heilongjiang 74. 9 Cotton stalk Jiangsu 75.1 Ba Maoshi

Red Sichuan 84.3 Straw Hebei 64.0 China Light Industry Press, "Texture of Plant Fiber Chemistry" published in 2001, published data on chemical analysis (wt%) and average fiber length (legs) of cotton stalk raw materials. The results are shown in Table 2.

Table 2

It is well known in the world today that the paper industry uses the traditional papermaking process more than 100 years ago. It uses strong acids, alkalis, and strong chlorine, and it discharges black water, which seriously affects the natural environment on which human beings depend. In recent years, Japan, India, Canada and other countries have developed the use of anthraquinone. Anthracene is a fused aromatic ring in aromatic hydrocarbons. All fused aromatic rings have been confirmed to have carcinogenic substances, such as the well-known carcinogenic structural formula composed of anthracene:

10-Methyl-1,2 anthracene or ethylene-1,2 anthracene are bleached with chlorine dioxide. The United States Environmental Protection Agency published in April 2000 a ban on the use of chlorine in papermaking bleaching. command. At present, 54% of the world's paper mills are turning to chlorine dioxide as a bleaching agent. However, 91% of chlorine dioxide and other organic compounds are combined, and the remaining 9% of chlorine emissions still endanger human living environment.

Oxidation bleaching dates back to the early 1950s. In 1952, Soviet woodland chemists Nikieih and ARim first discovered oxygen bleaching. Twelve years later, in 1964, French scientist Rebeve et al. Used magnesium salts to protect cellulose from oxidative degradation. 1970 In the United States, France, and Switzerland, three laboratories were successively established. In the same year, Ens trd in South Africa established the world's first chlorine dioxide bleaching plant. In 1972, the United States established a 12t oxygen bleaching plant and applied for a chlorine-free bleaching patent. Factors such as large losses, energy consumption, high water consumption, and product costs have not entered the industrialization. Twenty-seven years later, in 1999, the French company George Luther and the American company Purcell in 2001 began to use chlorine dioxide and ozone in combination with bleaching, but they still did not get rid of chlorine pollution. As of March 2002, when searching the patent data of various countries, the global paper industry has not left the cooking process that is seriously polluted by acids, alkalis, and chlorine, nor has it left the heavily polluted chlorine bleaching process; the treatment of lignochromic groups has remained In the traditional process of separating and degrading lignin more than 100 years ago, the global paper industry has become a key target of environmental organizations.

CN1212310A published by French Air Liquide on March 31, 1999, method of bleaching pulp by ozone and chlorine dioxide, CN1371439A American cuisine method published on September 25, 2002, CN1407172A published on April 2, 2003 Invented method and system for producing pulp using non-wood as raw material and CN1198492 published by Chinese Weichang Normal University in Shandong, a pollution-free method for making paper pulp, CN1229155, an alkali-free pulp method, CN1458075 — Polyoxometalate electrochemical bleaching pulp technology.

After reading all the above invention patents, some are chlorine-free bleaching, and some are reducing acid, alkali, The amount of chlorine used is to replace chlorine with ozone, and some are used with alkali, anthraquinone, and peroxyacid. As of March 2002, no one in the world did not use acid and alkali delignification, and no one completely banned acid and alkali chlorine, indicating that the above-mentioned invention did not control pollution from the source. The invention eliminates pollution from the source of the industry, and does not use strong acids, alkalis and chlorides, and does not use anthraquinone in the whole process from pulp delignification to bleaching. All papermaking wastewater is not discharged to the outside, forming a completely closed self-circulating zero Emissions have fundamentally solved the two major world problems of shortage of raw materials and serious pollution in the paper pulp industry. Summary of the invention

The technical problem to be solved by the present invention is to overcome the shortcomings in the prior art, and to provide a fully closed, self-circulating, zero-emission, pollution-free, oxidation-cleaning pulping process and its preparation method.

The clean pulping process and its preparation method of the present invention are realized through the following technical schemes, which are characterized in that the clean pulping process and its preparation method are made of non-wood or wood as raw materials and are prepared through the following processes:

(A) pre-processed raw materials;

(B) oxidizing and impregnating the pretreated material in the presence of active oxygen A and a cellulose protective agent composed of metal ions and metal ion ligands;

(C) grinding with active oxygen A first, and then grinding the oxidized impregnated material with active oxygen B;

(D) concentrating, beating,

Wherein the above-mentioned active oxygen A is selected from one or two of 0 ₂ , H ₂ 0 ₂ and the free radicals generated by it, and the active oxygen B is selected from 0 ₃ , 0 ₂ (single singlet oxygen), 0 / Η00 · (super Oxygen anion radical) One or more of its free radicals generated in the presence of an organic solvent in water.

The organic solvent is, for example, dimethyl sulfoxide or oxalic acid.

A pulp obtained by the above method.

In the method for cleaning pulping as described above, the non-wood material such as cotton stalks includes cotton bast, cotton stalks, cotton stalk roots and cotton stalk integrated fibers, stiff cotton and cotton linters, and cotton.潦, cellulose, hemicellulose, lignin contained in cottonseed, or a mixture of two or more of them. The wood includes coniferous wood, broad-leaved wood such as white pine, masson pine, Douglas fir, aspen, fast-growing poplar, birch and the like.

The metal ion is selected from one of Mg ⁺⁺ , Fe ⁺⁺ , Mn ⁺⁺ , Cu ⁺⁺ , A ⁺⁺ , Zn ⁺⁺ , and Si ⁺⁺ or a mixture of two or more thereof; the metal The ionic ligand is selected from the dihydrazone two correction page (Article 91 of the detailed rules) One of ethylene oxide (DMD), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), sodium amidate, polyoxyethylene alkyl ether or two or more of them mixture.

The amount of metal ions used is between 1 and 1000 ppm by weight.

The oxidative immersion treatment is performed under an acidic condition with a pH value of 1 to 4, and preferably the ablative immersion treatment is performed under an acidic condition with a pH value of 1.5 to 2.5.

The grinding treatment is performed under an acidic condition with a pH value of 1 to 4, and the grinding treatment is preferably performed under an acidic condition with a pH value of 2.5 to 3.8.

The acidic condition can be achieved by the active oxygen (for example, H00 ·) of the present invention, or it can be achieved by adding a pH adjusting agent.

1-50umol / L。 The concentration of the active oxygen A in the processed material is 0.01-2. Owt%, and the volume gram concentration of the active oxygen B in the processed material is 0.1-50umol / L.

A method for cleaning pulping as described above, the method has the following features and advantages: (A) Active oxygen is added dropwise to a disc mill and the rotating heat of the mill generates an energy transfer reaction to make cellulose from the intercellular layer (B) using the combined action of reactive oxygen species A and B to convert the chromophores in the lignin ", -aldehyde and ketone groups to carboxylic or dicarboxylic acid colorless groups; (C) ) Self-harm: The raw materials are sent to the oxidation reactor system after the pretreatment of the raw materials. All the two parts of the water used in the process are recirculated in the own plant: The first part is the water from the raw material purification treatment. After the centrifugal purification, the solid residue is transported. 1. The slurry is sent to the conventional beating section, and the fresh water generated is pumped into the circulating water purification tank. The purification tank is equipped with 0.1%-0.15% tribasic oxygen or ozone generator (0 ₃ generator). Clear water produces a decolorization reaction. The water contains traces of oxygen free radicals and is pumped into the circulating water use system. The second part is the oxidized water, which is purified by centrifugation and then treated with a conventional thickener. The slurry is sent to a storage tank for further reading. Paper workshop, water produced Circulating water purification plant into their own tank, the purified water pump feeding the processed feedstock purification system, a gasification system dipping, oxygen mill system, screening systems, their repeated use at the factory cycle.

The method uses molecular oxygen to generate an electron reduction reaction in an ion reactor to generate active oxygen radicals to transform and separate lignin, changes the chromophore group in the interlayer of plant cells, and obtains paper. This method fundamentally changes the traditional process of polluting acid, alkali, chlorine, anthraquinone and other chemicals with severe pollution. Using the invention not only eliminates the severely polluted cooking, traditional bleaching process, but also uses abundant annual Resources can also save energy and water and reduce product costs.

In this method, active oxygen is added to the material, and the grinding force is generated by mixing with a high-concentration hot mill. Reaction to change the chromophore of lignin in the interlayer of plant cells, and use the strong attack of hydroxyl radical formed by 3 oxygen atoms in molecular oxygen and the intra-molecular nucleophilic attack to make electrophilic reaction with lignin, so that The large π bond of the benzene ring of the lignin structural unit and the side chain is broken, which is degraded and dissolved, and the chromophore in the lignin is converted or decomposed into low molecules to generate colorless monocarboxylic acid or dicarboxylic acid.

The reaction is as follows:

The present invention also includes a pulp prepared by the above method.

Specifically, the method of the present invention is as follows:

An oxidation cleaning pulping process and a preparation method thereof are characterized in that the clean pulping process is made of non-wood or wood as a raw material and is prepared through the following processes:

(A) pre-treating raw materials;

(D) concentrating, beating,

Wherein the above-mentioned active oxygen A is selected from one or two of 0 ₂ , H ₂ 0 ₂ and the free radicals generated by it, and the active oxygen B is selected from 0 ₃ , 0 ₂ (single-state oxygen), 0 / book 0 · ( Superoxide anion radical) One or more radicals generated in the presence of an organic solvent in water.

'' When molecular oxygen undergoes a redox reaction through an ion radiator, it can obtain active oxygen, provide energy, and finally generate water. In the four electron processes that are accepted, each of the received electrons generates an oxygen radical, such as one electron reduction to generate a superoxide anion. Free radical, the reaction formula of which is 0 ₂ + e → 0 ^ / H00 ■, the reduction of two electrons to generate hydrogen peroxide, and the reaction formula is: 0 ₂ + 2e + 2H ⁺ →

6

Correction page (Article 91) H ₂ 0 ₂ , three-electron reduction to generate hydroxyl radicals, and the reaction of divalent iron and hydrogen peroxide to generate radicals, the reaction formula is: 0 ₂ + 3e + 3H + → H ₂ 0 + · 0H, Fe ^{2 +} + H ₂ 0 ₂ → Fe ^{3 +} + · 0Η + 0H—all are special free radicals for water treatment.

The metal ion is selected from, for example, one of Mg ⁺⁺ , Fe ⁺⁺ , Mn ⁺⁺ , Cu ⁺⁺ , A ⁺⁺ , Zn ⁺⁺ , Si ⁺⁺ , or a mixture of two or more thereof. The metal ion is generally provided in the form of a salt, such as ferrous sulfate, magnesium carbonate, and the like. The metal ion ligand is selected from, for example, dimethyldiethylene oxide (DMD), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), sodium alkylsulfonate, polyoxyethylene One of the alkyl ethers or a mixture of two or more of them. They are functional cellulose protection systems composed of different components with superoxide anion radicals (O ₂ "HOO ·) and hydrogen peroxide (H ₂ 0 ₂ ), respectively, which can protect cellulose and achieve the purpose of silicon removal. .

Pretreatment usually includes removing impurities, cutting, shredding, and cleaning as appropriate. The oxidative impregnation treatment is preferably performed under acidic conditions, for example, the pH value is between 1 and 4, preferably between 1.5 and 2.5.

The grinding treatment is preferably carried out under acidic conditions, for example, the pH value is between 1 and 4, preferably between 2.5 and 3.8.

The acidic condition can be achieved by the active oxygen (for example, H00 ·) of the present invention, and can also be achieved by adding a pH adjuster.

The metal ions are usually used in the form of a salt, and the amount of the metal ions is generally between 1 and 1000 ppm, preferably between 10 and 1000 ppm by weight of the metal ions.

The non-cooking method in the present invention refers to the elimination of the cooking section, and the active oxygen is added dropwise to the disc mill, and the rotation heat of the mill generates an energy transfer reaction to separate the cellulose from the intercellular layer.

The traditional free bleaching method of the present invention refers to the use of reactive oxygen species and B to convert chromogenic groups in lignin to colorless groups without using a bleaching stage, such as converting ",-caseone groups into Carboxylic or dicarboxylic acids.

According to a preferred embodiment of the present invention, the method of the present invention includes:

. Raw material pretreatment system: refers to a working section that cooperates with the raw material pretreatment system. After the material is depodized by a cracker, it is cut into 5cm long and 1.5cm thick materials with a molding rate of 98%. Rolls are used. The pressure cracker is broken into a velvet shape, the wind is used to remove dust and cores, and the purifier is used to wash away debris. The water of the purifier is to completely close the circulating water in the plant. Traces of active oxygen free radicals and traces of cellulose remain in the water. Protective agent (available in the market), so correct the page (Article 91) There is no need to add active oxygen during the pretreatment, and the materials are cleaned with circulating water without pollution by drainage, which changes the pollution process of the traditional process of acid washing and alkaline washing.

Oxidation reactor system (see Chinese invention patent application 200310103895. 3): The main function is to soak, soften, and degumme the material. The pH value in the kettle is 1-4, and the active oxygen generates superoxide anion radicals in weakly acidic water ((ή / Η00 ·), has a strong permeability, can directly penetrate the interlayer of plant cells for oxidation reaction. There is a stirrer in the oxidation reactor, which is connected to and driven by an external motor through the top of the oxidation reactor. The stirring slurry of the stirrer is at least three layers, and the rotation speed can be adjusted. The stirrer is started so that the positive ions generated by the electrodes in the kettle in the water soften the material under the combined effect of pressure and the shear force of the stirrer and water temperature. The active oxygen in the kettle decomposes the linked layer, pectin, and polypentose at the same time in a high-speed agitation to produce a decoloring reaction. After repeated experiments by the inventor, it is preferred that the pH in the kettle is 1.5 to 2.5, plus 0.02 -0.1% pre-formulated cellulose protective agent, stirring speed reaches 40-80 times / minute, within 40-60 minutes, the chromophore of the material in the kettle changes from dark yellow to light white, and is washed repeatedly Wash and squeeze.

Grinding system: A disc mill system is preferred: It consists of two parts: RL50S disc mill or high-concentration thermal mill and oxidation reactor. In the process, there are two types of grinding: active oxygen A for the first mill and active oxygen B for the second mill. The material is output by the oxidation impregnation system, and evenly fed into the mill by a screw feeder, and then impregnated with ozone having a volume gram concentration of 1-15umol / L, the weight percent concentration of water is 30, the value of 2.5 is 5. The speed is 600-1200 times / minute, the mill gap is 0.2-0. 15mm;-the weight of the spray water in the spraying water is constantly increased to a concentration of 0 · 1-1. 5 active oxygen A is mixed with the material. The mill softens the material and separates the cellulose coated in the intercellular layer. The main function of the frictional thermal reaction is to mix the active oxygen with the material to make the frictional force of the mill speed generate a heat transfer reaction. It depends on the superoxide anion radicals and molecules. Oxygen and hydrogen peroxide are used to oxidize the chromophores in phenylpropane, plus the difference in softening temperature between lignin, hemicellulose, and cellulose. Fine fibers are oxidized into hydrophilic groups and can be linked. On the cellulose main chain, increase the yield by 8-12%. The key of the present invention is the process conditions (process sequence, pH value, temperature, active oxygen consumption, time, speed, pressure, pulp consistency, etc.) content .

The process system has one mill and two return points. The sorted grinding slag can be repeatedly reground and re-screened. After being transferred to the purifier, the edible grade citric acid and weight of 0.12 are added. After spraying hydroxylamine with a concentration of 0.01, the pulp was beaten according to the conventional process to prevent paper disease and oxidative discoloration. The pulp was the original pulp with a yield of 76% and an ISO whiteness of 52-65. . This section can build a raw pulp processing production line in a region with abundant resources and raw materials to provide raw material guarantee for central enterprises.

The original slurry is continuously fed into the mill with a screw feeder, and in a grinding process, the previously prepared 0 ₂ with a weight percentage of 0.1 and / or H _{2 with a} weight percentage of 1.5 are added dropwise. 0 ₂ , Adding amount and slurry ratio is 1: 0.12-0.15 by weight, mixed with slurry, mill speed is 1300 times / min, mill gap is adjusted to 0.15-0.1 color, temperature is 60-80Ό, The consistency of the pulp reaches 12-15%, the value of 11 is 2.5-3.8, and the observed whiteness of the pulp is 65-75. ; In the second mill process, ozone and / or a superoxide anion radical (0 ^ / HOO ■) and / or a molar amount of about 10umol / L are added dropwise. The concentration of singlet oxygen is about 10umol / L), the working pressure is 0.3-0.6MPa, the rotation speed is 1300 times / min, the mill gap is adjusted to 0.15-0, 1 let, the temperature is 80-10 (TC, the slurry concentration is 12-15% , 8 value 2.5-3.8, mixed with pulp 0.5- lh, ISO whiteness should be 75-86 °, enter the conventional fine sieve, purification, cylinder concentration, pulping, storage slurry process system, if you need to whiten, you can According to the operation process, it was repeated once more, and the pulp yield was 75%.

Compared with the prior art, the method of the present invention has the following beneficial effects: The present invention can achieve full closure, zero emissions, self-circulation, no acid, no alkali, no chlorine, no anthraquinone, no cooking, no bleaching, no The method of polluting clean papermaking pulp has the characteristics of energy saving, water saving and clean pulping, fundamentally solves the pollution of pulping and papermaking industry, promotes the reuse of agricultural and forestry resources, and protects the ecological environment. The fully enclosed self-circulation and zero discharge means that the raw materials are sent to the oxidation impregnation reaction system after the pretreatment of the raw materials. All the two parts of the water in the process flow are recirculated in the own plant, and the other part is the solid residues after centrifugal purification. It is sent to the conventional beating section, and the fresh water produced is sent to the circulating water purification tank in the factory. The purification tank is equipped with a 0.1% -0.15% tribasic oxygen or ozone generator ( ₀₃ generator) to produce a decolorization reaction to the water. It contains trace oxygen free radicals and is pumped into the circulating water use system; the other part is processed by a conventional thickener after centrifugal purification, and the slurry is sent to a storage tank and entered into a papermaking workshop. The generated water is filtered into the circulating water in its own plant. The purification tank pumps the treated purified water to a raw material purification system, an oxidation impregnation system, an oxygen mill system, and a screening system, and is repeatedly used in its own plant. The process of the invention has no gas discharge and no black water discharge, and the discharged solid waste residue accounts for 12% to 22% of the total weight, and does not pollute the environment. The waste residue can be sent to a biological treatment tank for other purposes. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart of the clean pulping process of the totally enclosed zero-emission oxidation method of the present invention.

9

Correction page (Article 91) detailed description

The following further describes the present invention based on the embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the invention. Example one

Take 100kg of cotton stalks and remove the pods with a cracking machine, cut into 5cm long and 1.5cm thick materials with a molding rate of 98%, and use a roll-type cracking machine to crack into velvet, wind dust, core removal, and sieve impurities After the circulating water was washed, it was fed into the oxidation reactor with automatic stirring using a screw conveyor. The reaction temperature was 60 ° C, the pH in the kettle was 2.5, and 0.02 kg of magnesium carbonate and dimethyl dioxirane 0.01 were added. kg (DMD), stirring speed 60 times / minute, add H ₂ 0 ₂ solution after 0.5h, control its weight percentage concentration to 0.2, stir and accelerate 80 times / minute after adding, temperature is 80 "C, observe kettle after 1h The soaking and swelling softness rate of the medium material reaches 98%. The material in the kettle changes from dark yellow to light white. The material meets the international standard ISO whiteness of 48-52 ° (hereinafter referred to as whiteness or ISO whiteness). After repeated washing, squeezing and concentrating, the weight percent concentration of water is 30, and the H ₂ 0 ₂ solution is added dropwise to the washed material, and the weight percent concentration in the material is 0.2, which are all fed into the mill with a screw feeder Mixed grinding, the speed is 600-1200 times / minute, the mill gap is adjusted to 0.2mm-0.15mm, the slag after screening can be adjusted After re-grinding, sieving, and transferring to a purifier for treatment, add edible citric acid with a concentration of 0.12 by weight and hydroxylamine with a concentration of 0.01 by weight. After leaching, use the conventional pulping process to beat the pulp. Slurry with a yield of 76% and ISO whiteness of 52-65. This section can generally set up a rough pulp processing production line in areas where raw materials are concentrated to provide the original slurry for central production enterprises.

Example two

100 kg of the original slurry in Example 1 was fed into the mill uniformly and continuously with a screw feeder. In a milling process, H ₂ 0 ₂ having a weight percent concentration of 1.5 prepared before was added dropwise and dropped by weight. Adding amount and slurry ratio is 1: 0.12, mixed with slurry, mill speed is 1300 times / min, mill gap is adjusted to 0.15-0.1 legs, temperature is 60 ° C, slurry concentration is 12-15 by weight %, H value of 3.8, observing the whiteness of the pulp is 65-75 °; the second mill drops the volume gram concentration of ozone of about 10umol / L, the applied pressure is 0.4MPa, the rotation speed is 1300 times / min, and the mill gap is adjusted to 0.1mm , The temperature is 80 ° C, the pulp concentration is 12-15% by weight, the pH value is 3.8, and it is mixed with the pulp for 0.5 -lh, and the whiteness should be 75-86 °. After entering the conventional fine sieve, purification, round screen concentration, beating, storage Pulp process system, if you need to whiten again, you can repeat it according to the operation process.

10

Correction page (Article 91) 75%.

Example three

The same procedure as in Example 1 was repeated, except that magnesium carbonate was replaced with magnesium carbonate of the same weight to obtain the original slurry.

Example 4

The same procedure as in Example 2 was repeated, except that the superoxide anion radical (0 ^ / HOO ·) with a molar concentration of 10umol / L was used to replace the ozone with a molar concentration of about 10umol / L. Example 5

Take 100 kg of poplar chips and crack them into a velvet shape with a roller-type cracking machine, remove impurities by wind dust removal, wash with circulating water, and use a screw conveyor to enter the oxidation reactor with automatic stirring. The reaction temperature is 60 ° C. pH value 2.5, add magnesium sulfate 0.015kg and dimethyldioxirane G.01kg (DMD), stirring speed 60 times / minute, add H ₂ 0 ₂ solution after 0.5h, control its weight percentage concentration to 0.2 After the addition, the stirring was accelerated 80 times per minute, and the temperature was 100 ° C. After lh, the material in the kettle was observed to soak, swell, and soften up to 98%. The material in the kettle changed from dark yellow to light white, and the raw raw material ISO whiteness was 48-52. After repeatedly washing, squeezing, drying, and concentrating the material, the water content is 30%, and the washed material is added dropwise with a solution of 0 ₂ and H ₂ 0 _2. The weight percentage concentration of the material in the material is 0.25. Hook into the mill for mixing, the speed is 600-1200 times / min, the mill gap is adjusted to 0.2mm-0.15mm, can the slag after screening be reground, rescreened, transferred to the purifier for processing, and add weight Food grade citric acid with a concentration of 0.12 and N, N-dialkylhydroxylamine with a weight concentration of 0.01 are dipped and beaten according to a conventional pulping process. The pulp is an original pulp with a yield of 76%. ISO whiteness is 52-65. .

Example Six

Using 100 kg of the original slurry in Example 5, use a screw feeder to continuously and uniformly feed the mill into the mill. In a milling process, the previously prepared weight percentage concentration of 0.1 ₂ and 1.5 ₂ H ₂ 0 ₂ are added dropwise. The compound oxygen is composed of a dripping amount and a slurry ratio of 1: 0.15, mixed with the slurry, the mill speed is 1300 times / minute, the mill gap is adjusted to 0.15-0.1mm, and the temperature is 60 "C, The consistency of the pulp is 12-15% by weight, the pH value is 3.8, and the whiteness of the pulp is observed to be 65-75. The second mill is added dropwise with a supermolecular anion radical with a molar concentration of about 10umol / L (0 / HOO ·) , The applied pressure is 0.4MPa, the rotation speed is 1300 times / minute, the mill gap is adjusted to 0. lmm, the temperature is 80 ° C, the pulp concentration is 12-15% by weight, 3 is 3.8, and the mill is mixed with the pulp for 0.5- lh,

11

Correction page (Article 91) I SO whiteness should be 75-86. , Into the conventional fine sieve, purification, round screen concentration, beating, storage process technology system, if you need to whiten again, you can repeat the operation process again, the yield of 75%.

Example Seven

The same procedure as in Example 5 was repeated, except that the same weight of diethylenetriaminepentaacetic acid (DTPA) was used instead of dimethyldioxiran to obtain the original slurry.

Example eight

The same procedure as in Example 6 was repeated, except that the singlet oxygen θ ₂ ) with a molar concentration of 10 umol / L and the ozone (0 ₃ ) with a molar concentration of 1 Oumol / L were used instead of 10 molol. / L of superoxide anion radical (O HOO ·).

According to the present invention, there is no cooking, no bleaching, fully closed self-circulation, and active oxygen mixed milling process, and no need to add chemicals such as strong acid, strong alkali, chloride, etc. The enterprise can manufacture various types of medium and high-grade pulp according to market demand.

Oxidation clean pulp test results

The inventors entrusted the pilot plant products of cotton stalk, mulberry, poplar pulp and cotton stalk fine pulp to Tianjin University of Science and Technology for testing. The results are detailed in the test report (Table 3). From the test data, oxidation pulping is not only used for wood but also for non-wood, such as agricultural waste cotton stalk is an available pulping raw material.

The test report and the national bleached sulfite pulp comparison table issued by Tianjin University of Science and Technology on November 12, 2003 are shown in Table 3.

table 3

Bleached sulfite

Index name Cotton scale coarse pulp Cotton stalk fine pulp Mulberry coarse pulp Poplar coarse pulp Salt pulp standard

Fiber length (average weight mm) 0. 50 0. 51 0. 65 0. 47 0. 55 Beating degree (° SR) 45 59 51. 5 58 62 Basis weight (g / m ² ) 58. 2 58. 2 60. 0 59. 0 57. 5 Tightness (g / cm ³ ) 3. 3 0. 33 0. 32 0. 33 0. 32 Crack length (Km) 3. 2 3. 81 3. 44 3. 44 3. 07 Tear Index (raNmVg) 2. 8 2. 9 3. 4 2. 9 2. 5 Burst Resistance Index (KPamVg) 1. 5 1. 9 1. 5 1. 7 1. 4 Whiteness (% IS0) 82 0 68. 69 71. 58 70. 87 75. 17 Opacity (%) 88. 1 95. 91 93. 91 96. 05 94. 07

Claims

Rights request

1. The present invention relates to a fully enclosed zero-emission oxidation clean pulping process and a preparation method thereof, which are characterized in that the clean pulping process and a preparation method thereof are made of non-wood or wood as a raw material and are prepared through the following processes :

(A) pre-treatment raw materials;

(C) First grinding with active oxygen A, and then grinding the oxidized impregnated material with active oxygen B;

(D) concentration, beating,

The active oxygen A is selected from one or two of 0 ₂ , H ₂ 0 ₂ and the free radicals generated by the active oxygen A, and the active oxygen B is selected from 0 ₃ ,

C singlet oxygen), O HOO (superoxide anion radical) One or more of the radicals generated in the presence of an organic solvent in water.

2. The method according to claim 1, characterized in that the non-wood material such as cotton stalks includes cotton bast, cotton stalks, cotton stalk roots and cotton stalk integrated fibers, stiff cotton and cotton linters, cotton Cellulose contained in dregs and cottonseeds; one of hemicellulose and lignin, or a mixture of two or more thereof; the wood includes coniferous wood, broad-leaved wood such as white pine, masson pine, Douglas fir Pine, aspen, fast-growing poplar, birch, etc.

3. The method according to claim 1, wherein one of said metal ion is selected from ^{^{^{Mg ++, Fe H, Mn ++}}} , Cu ++, ΑΓ ++, Zn ++, Si ^ or A mixture of two or more of them, the metal ion ligand is selected from the group consisting of dimethyldioxirane (D), diethylenetriaminepentaacetic acid (DTPA), ethylenediaminetetraacetic acid (EDTA), alkane One of sodium sulfonate and polyoxyethylene alkyl ether or a mixture of two or more of them.

4. The method according to claim 1, wherein the amount of said metal ions is between 1 and 1000 ppm by weight.

5. The method according to claim 1, wherein the oxidative immersion treatment is performed under an acidic condition with a pH between 1 and 4.

6. The method according to claim 5, characterized in that the oxidative immersion treatment is preferably performed under acidic conditions with a pH value of 1.5 to 2.5.

7. The method according to claim 1, wherein the grinding treatment is performed under an acidic condition with a pH value between 1 and 4.

8. The method according to claim 7, characterized in that the grinding treatment preferably has a pH

13

Correction page (Article 91) Performed under acidic conditions with a value of 2.5-3.8.

9. The method according to claim 1, characterized in that the concentration of the active oxygen A in the processed material is 0.01-2.0 wt%, and the volume gram of the active oxygen B in the processed material The concentration is 0.1-50umol / L.

10. The method according to claim 1, which has the following features and advantages:

(A) During grinding, the active oxygen is added dropwise to the disc mill, and the rotation heat of the mill generates an energy transfer reaction to separate the cellulose from the intercellular layer;

(B) using the combined action of reactive oxygen species A and B to convert chromophores, β-aldehydes and ketones in lignin to carboxylic or dicarboxylic acid colorless groups;

(C) Self-circulation: After the raw materials are pretreated, they are sent to the oxidation impregnation reaction system. All the used water in the process flow is returned to the factory to circulate. The first part is the water after the raw material purification treatment. The slag is transported away, and the slurry is sent to the conventional beating section. The clean water produced enters the circulating water purification tank in the factory. The purification tank is equipped with a 0.1%-0.15% tribasic oxygen or ozone generator. It contains a small amount of oxygen radicals and is pumped into the circulating water use system. The second part is the oxidized water, which is purified by centrifugation and then treated with a conventional thickener. The slurry is sent to the storage tank and entered into the papermaking workshop. The water is filtered into the circulating water purification tank in the factory, and the treated purified water is pumped to the raw material purification system, the oxidation impregnation system, the oxygen mill system, and the screening system, and is repeatedly recycled in the factory.

11. A pulp obtained by a method according to any one of claims 1-10.