WO1998026128A1

WO1998026128A1 - Method for storing and transporting cellulosic and process for manufacturing pulp

Info

Publication number: WO1998026128A1
Application number: PCT/JP1996/003620
Authority: WO
Inventors: Akio Mita
Original assignee: Akio Mita
Priority date: 1996-12-11
Filing date: 1996-12-11
Publication date: 1998-06-18
Also published as: AU6485598A

Abstract

A method of storing or transporting cellulosic, such as bagasse and rice straws while preventing the same from being rotten. This method is characterized in that cellulosic is brought into contact with an alkali material or a mixture of an alkali material and hydrogen peroxide. The pulp can be manufactured easily by using this cellulosic stored or transported.

Description

Specification

TECHNICAL FIELD The present invention relates to a method for storing and transporting a cellulosic material and a method for producing pulp.

TECHNICAL FIELD The present invention relates to a method for storing and transporting a cellulosic material, and a method for producing pulp. Background art

Cellulose-based substances such as wood, agricultural products, and agricultural waste are used in large quantities as pulp raw materials and feed, but logging of wood has become strongly regulated due to environmental issues and other factors. Tropical agricultural waste such as bagasse (sugar cane cake after squeezing sugar solution) and banana leaves has been attracting attention as a cellulosic substance that replaces wood. With great difficulty.

Various methods have been attempted to store cellulosic materials. For example, the water content is about 12 weight ° /. If dried to the following level, raw materials can be stored for a long period of time without spoiling. However, if a large amount of substance is dried to a water content of 12% by weight or less, the drying cost increases, so that the method is not suitable. There is also a method of storing a cellulosic substance using a synthetic preservative such as a chlorine-based or phenol-based preservative, but this is not a preferable method in terms of safety and cost. In addition, a method of storing an organic acid by adding an organic acid to a cellulosic substance is also known. For example, bagasse with residual sugar solution is fermented by lactic acid fermentation to delay the decay of the bagasse during storage, and in cold-aged areas, grass is added with propionic acid and stored. However, under hot and humid conditions, it is difficult to completely prevent fermentation and spoilage such as acetone butanol fermentation even with organic acids, which is bad. The cellulosic material rots while generating odor. Disclosure of the invention

An object of the present invention is to provide a method for storing and transporting a cellulosic substance without spoiling even under high temperature and high humidity conditions, and a method for producing pulp from the cellulosic substance stored or transported by the method. . As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that, when a cellulose-based material is stored or transported in contact with an alkaline substance, rot during storage and during transportation can be prevented. In addition, the cellulosic material stored and / or transported by the above method is permeated into the inside of the cellulosic material and mild defibration progresses with the passage of time. The present inventors have found that a cellulosic material is suitable as a pulp raw material, and have completed the present invention based on these findings.

That is, according to the present invention, the storage and transportation of a cellulosic material characterized by storing or transporting the cellulosic material while contacting the cellulosic material with an alkaline substance, or while contacting the cellulosic substance with an alkaline substance and hydrogen peroxide. Transportation methods are provided.

Further, according to the present invention, a cellulosic substance stored and / or transported by the above-described method is used, and this is mechanically and mechanically or chemically treated to be defibrated. A method for producing pulp is provided.

The cellulosic substance used in the present invention is a plant or an additive containing cellulose, such as coniferous or hardwood wood, rice straw, bagasse, banana leaf or stem, pineapple leaf, corn leaf or stem, Mitsu also includes various species of hemp and pasture. In addition, these cellulosic materials should be cut into small pieces and stored or transported so that they can be in good contact with the alkaline substances. Is preferred. Specifically, it is desirable to store and transport it after cutting it to a length of 0.5 to 20 cm, preferably 2 to 7 cm. The water content of the cellulosic material is not particularly limited, and may be a water-containing substance having a water content of higher than 12% or a dried substance having a water content of 12% or less.

The storage method and the transport method of the present invention are characterized in that a cellulosic substance is contacted with an alkaline substance or is contacted with an alkaline substance and hydrogen peroxide to be stored or transported. It is preferable that the alkaline substance used in the present invention is easily soluble in water and easily penetrates into the cellulosic substance. It is desirable that the surface of the cellulosic material to be stored or transported be brought into contact with the alkaline substance so as to have a pH of 9 or more, preferably pH 9 to l 2.

Specific examples of the alkaline substances used in the present invention include hydroxides, oxides, carbonates, hydrogencarbonates, organic acid salts, silicates, and peroxides of sodium hydroxide. And the like; hydroxides and oxides of calcium and magnesium, peroxides and the like, and hydroxides and carbonates of sodium hydroxide are particularly preferred. These alkaline substances may be used alone or as a mixture of two or more kinds, or various additives may be mixed and used as long as the alkaline properties are not impaired. In addition, these alkaline substances can be added to the cellulosic substance in the form of a solid, an aqueous solution, or a slurry.

In the case where the liquid substance is added to the cellulosic substance in a solid state, the cell mouth substance is in a wet state, and when the liquid substance is deliquescent or easily soluble, the liquid substance is added. The average particle size of the alkaline substance may be 5 mm or less, but usually, the alkaline substance has an average particle diameter of 100 μm to improve the contact between the alkaline substance and the cellulosic material. m or less, preferably 5 to 50 μm. The amount added is Although it varies depending on the type of the active substance, it is generally 1 to 50% by weight, preferably 3 to 30% by weight of the absolutely dry cellulosic substance.

When the alkaline substance is added to the cellulosic substance as an aqueous solution, it is desirable to add the alkaline substance as an aqueous solution having a concentration of 0.5 to 25% by weight, preferably 3 to 15% by weight. The amount added is such that the weight ratio (%) of the alkaline substance to the absolutely dry cellulosic substance is 5 to 50% by weight, preferably 10 to 30% by weight.

When the slurry is added to the cellulosic material in the form of a slurry, the amount of the addition is preferably 5 to 50% by weight, in terms of the weight ratio (%) of the slurry to the absolutely dry cellulosic material. Is an amount of 10 to 30% by weight.

The alcoholic substance used in the present invention prevents cellulosic substances from decay by microorganisms, solubilizes non-cellulose substances such as lignin and resin contained in the cellulosic substances, and converts the cellulosic substances into fibers. It shows the effect of opening the shape. Therefore, the cellulosic material obtained by the storage and transportation method of the present invention is suitable as a pulp raw material.

When the cellulosic material is stored or transported in contact with the alkaline substance according to the present invention, the cellulosic substance is brought into contact with an alkaline substance and hydrogen peroxide to prevent the decay of the cellulosic substance. In addition to being effective, it decomposes easily decomposable components such as lignin in the cellulosic material, promotes the opening of the cellulosic material, and has the effect of bleaching the cellulosic material. Therefore, a cellulosic substance stored or transported while being brought into contact with an alkaline substance and hydrogen peroxide is suitable as a pulp raw material.

A method of contacting a cellulosic substance with an alkaline substance and hydrogen peroxide; and A method of adding hydrogen peroxide or a hydrogen peroxide generator to an aqueous solution of an alkaline substance and adding this aqueous solution to a cellulose-based substance, or a method of adding a powdery mixture of an alkaline substance and a hydrogen peroxide generator to a cellulose-based substance There is a method to add to the substance. As the hydrogen peroxide generator, conventionally known ones can be used. Examples of such a hydrogen peroxide generator include water-soluble percarbonates such as sodium percarbonate and potassium percarbonate, sodium perborate, and the like. Various perotasoates such as water-soluble perborate such as potassium perborate, sodium persulfate, and water-soluble persulfate such as persulfuric acid potassium, and urea Z hydrogen peroxide adduct , Metasilicate Z hydrogen peroxide adduct, calcium peroxide, sodium peroxide and the like. The addition amount of hydrogen peroxide to the cellulosic material, to the bone dry cellulosic material, and with H ₂ 〇 ₂ 0. 3% by weight or more, good Mashiku is from 1 to 5 wt%.

When storing or transporting cellulosic materials in contact with alkaline substances and hydrogen peroxide, water glass or heavy metal chelators should coexist in order to prevent decomposition of hydrogen peroxide by heavy metal ions. I like it. Examples of such heavy metal chelating agents include hitherto known ones, for example, citric acid or a water-soluble salt thereof, EDTA (ethylenediaminetetraacetic acid) or a water-soluble salt thereof, DTPA (diethylenetriaminepentaacetic acid) or a water-soluble salt thereof. Other than the polyvalent carboxylic acids such as, and the like, diphosphonic acid represented by the following general formula (I) or a water-soluble salt thereof and the like can be mentioned, and the use of diphosphonic acid or a salt thereof is preferable. ORO

H O— P-C P— O H (I)

O H O H O H

(However, R represents an alkyl group having 1 to 11 carbon atoms.) It is also preferable to contact a cellulose compound with a magnesium compound. Magnesium compounds have the effect of preventing the decomposition of cellulose and protecting cellulose. The amount of the magnesium oxide added is about 0.01 to 0.5% by weight based on the weight of the cellulosic substance. The magnesium compound is preferably added in the form of a water-soluble compound. Specifically, one or more of the magnesium compound, chloride, carbonate, sulfate, hydroxide, lactate, acetate and the like are added. Is added.

When the cellulosic material is stored or transported as a pulp raw material according to the present invention, use of an alkali aqueous solution (hereinafter, also simply referred to as a cooking liquor) used as a pulp cooking liquor is used as the alkaline substance. preferable. The cellulosic material stored or transported in contact with such cooking liquor can be digested in the cooking liquor as it is as a pulp raw material. As the cooking liquor, a conventionally known cooking liquor can be used. Examples of such cooking liquor include a cooking pulp method (KP method) containing sodium hydroxide and sodium sulfide. Cooking liquor of the alkali pulp method (AP method) containing sodium hydroxide; cooking liquor of the semi-chemical method containing sodium sulphite and sodium hydrogen carbonate; Hydroxide, carbonate Or a PA digestion liquid containing a hydrogen carbonate and a hydrogen peroxide or a hydrogen peroxide generator, and additionally containing a chelating agent, a magnesium compound, and the like.

A particularly preferred cooking liquor among the above-mentioned cooking liquors is a PA method cooking liquor. This is because the cooking liquor contains hydrogen peroxide, so that the cellulose-based material is gradually unraveled during storage and transportation, and the bleaching of the pulp produced by defibration proceeds. is there.

In order to store the cellulosic substance according to the present invention, an alkaline substance is added to and mixed with the cellulosic substance, and the resulting mixture is deposited on the ground, covered with a sheet, placed in a silo, a container, or the like. And store. On the other hand, in order to transport the cellulosic material, the mixture is transported in a tank container or a large bag. The temperature for storing and transporting the cellulosic material is not particularly limited, and may be a cooled temperature or a heated temperature, but is usually room temperature.

When pulping the cellulosic material stored or transported according to the present invention, the pulping depends on the degree of opening of the cellulosic material, but conventionally known mechanical pulping methods and chemical pulping methods Can be performed. The chemical pulping method in this case includes a semi-chemical pulping method in addition to various conventionally known chemical pulping methods. The semi-chemical pulping method is a method of performing a chemical treatment before mechanically fibrillating a cellulose-based material. And chemimechanical pulping method.

When pulping the cellulosic material stored or transported according to the present invention, a great advantage can be obtained as compared with pulping the cellulosic material stored or transported by a conventional method. That is, the conventional For pulping of cellulosic material stored or transported by the method, it does not penetrate alkaline substances and does not undergo any fibrillation by delignification, etc. It is necessary to use a large pressure-resistant reactor, and to digest at a high digestion temperature over a long period of time. On the other hand, in the cellulosic material stored or transported according to the present invention, an alkaline substance permeates during the storage or transport period, and a certain degree of fibrillation has already been achieved by delignification from the cellulosic material. Therefore, the pulping is very easy, and as a result, the ratio of the nocellulosic substance in the cooking liquor is reduced, the reactor may be downsized, and the cooking temperature may be low. In addition, the cooking time is short. Therefore, pulp productivity is significantly improved. For example, when the cooking temperature and the cooking time of the cellulose raw material stored or transported according to the present invention are shown, the cold soda method does not require heating at all, and the cold soda method does not require any heating. The cooking temperature can be as low as 80 to 170 ° C, preferably 100 to 140 ° C, and the cooking time is generally 2 to 360 minutes, It takes 1 to 5 minutes for the thermomechanical method and the chemomechanical method, and 15 to 120 minutes for the chemical method. Also, the liquid ratio

The (weight ratio of the cooking liquor Z-cellulose-based material) is 0.6 to 6 liters Z kg, preferably 1.5 to 3 liters kg, and can be significantly reduced. Example

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples. The percentages described below are all percentages by weight. Example 1

15% sodium hydroxide was added to 4 2 • 2 kg (24.4 kg absolute dry weight) of rice stems, which were cut to a length of about 5 cm and then air-filtered to remove the leaves. The solution was added as an aqueous solution to a liquid ratio of 2.1 liter g, mixed with stirring, and stored at room temperature for 18 months in a poly tank. The room temperature dropped to 4 ° C in winter and rose to 38 ° C in summer, but there was no phenomenon that the stem of the rice rot deteriorated during storage.

The rice stems after storage for 18 months were directly defibrated with a disc refiner to obtain cold soda pulp with a bone dry pulp yield of 67.8% from bone dry raw materials. This pulp had a Hunter brightness of 22.4%, a breaking length of 2.5 km, a specific burst strength of 2.2 and a specific tear strength of 48. Example 2

The sugar cane is divided by a can separator, and the plate-like skin (key inlaid) from which the screws and shells have been removed is cut to a size of 2.5 to 3.0 cm x 3.5 to 5.0 cm. It was a tip. This chip 30.0 t (absolute dry weight 14.1 t) 〖, hydroxylation power 4.33 t, and in the above general formula (I), R is a hexyl-group diphosphonic acid 169 kg Then, 1.3 kg of magnesium oxide, 21.2 kg of amylantraquinone, 42 kg of hydrogen peroxide, and purified water in a liquid ratio of 1.3 liters Zkg were added. This was stirred well so that the chips were uniformly immersed in a uniform aqueous solution. This was stored in a silo for 18 months, but no deterioration of chips was observed during storage. The temperature inside the silo was 50 ° C at the maximum and 23 ° C at the minimum. The wet chips stored as described above were taken out of the silo, heated to 125 ° C with a hot refiner, and defibrated while holding for 2 minutes to obtain unbleached pulp. The absolute dry pulp yield from the absolutely dry raw material was 78.2%, the hunter brightness of the pulp was 62.3%, the breaking length was 4.2 km, the specific burst strength was 2.3, The specific tear strength was 75. Example 3

The stem of Abba power (Manila hemp) was cut to 15 cm in length, crushed with a roller, and added with amylase, pectinase and amylase, and fermented at 100 to 55 ° C for 3 hours. By this treatment, crude fiber was obtained in which 80% of pectin and 95% of starch in the raw material were removed. 25 kg of this crude fiber (5.2 kg of absolute dry weight), 1.07 kg of sodium hydroxide, 10.4 g of t-butylanthraquinone, and R in the above general formula (I), where 1.5 g of diphosphonic acid, 32.6 g of magnesium carbonate and 156 g of hydrogen peroxide and an amount of purified water with a liquid ratio of 1.9 liters Zkg were added. Stirring was performed so that the crude fiber was uniformly immersed in a uniform aqueous solution. This was stored in a plastic tank at room temperature for 20 months, but no signs of rotting degradation of the crude fiber during storage were found. The room temperature was 23 ° C at the minimum and 38 ° C at the maximum.

The contents of the polytank after storage are transferred to an earth pot, where they are heated to 115 ° C for 1 hour, then the contents are taken out and separated into waste liquid and solids. A bleached pulp was obtained. This pulp had a Hunter brightness of 67.5%, a breaking length of 9.2 km, a specific burst strength of 5.8, a specific tear strength of 198 and a kappa monovalent of 5.2. Was. The absolute dry pulp yield from absolutely dry raw materials was 62.7%. The above-mentioned unbleached pulp (3.26 kg, absolute dry weight) was mixed with 97.8 g of hydrogen peroxide, 126.2 g of sodium hydroxide and 2.6 g of magnesium oxide, and the above general formula ( In I), bleach by immersing for 1 hour at 90 ° C in a homogeneous aqueous solution consisting of 26 g of diphosphonic acid in which R is octyl group, 65.2 g of commercial water glass, and 28 liters of purified water. Then, bleached pulp was obtained. The bleaching yield was 96.2%, and the Hunter whiteness of the bleached pulp was 82.5%. Example 4

5.2 kg of wood material with a length of 2.8 to 3.2 cm (28.5 kg of absolute dry weight), 89.4 kg of sodium hydroxide, and 57.8 g of hydroxyanthracene And 1.16 kg of DTPA, 805 g of magnesium carbonate, 7.5 kg of hydrogen peroxide, and purified water with a liquid ratio of 3.2 liters Zkg. With good stirring, the chips were immersed uniformly in a uniform aqueous solution. This was stored in a plastic tank for 24 months indoors, and no signs of decay of the chips during storage were observed. The room temperature was a minimum of −3 ° C. and a maximum of 30 ° C.

After storage, the contents of the poly tank are transferred to an earth pot, heated at 145 ° C for 1 hour, digested, the contents are taken out of the earth pot, separated into waste liquid and solids, and then the solids are separated. Unbleached pulp was obtained by selective washing with water. This pulp had a hunter brightness of 45.6%, a kappa monovalent of 9.3, a breaking length of 5.7 km, a specific burst strength of 4.4 and a specific tear strength of 98. The absolute dry pulp yield from absolutely dry raw materials was 53.2%. Example 5

To 30 kg (15.3 kg absolute dry weight) of wet bagasse from Okibashi without screws, 2.15 kg of sodium percarbonate, 600 g of water glass, 900 g of diphosphonic acid of general formula (I) in which R is C ₆ groups, 70 g of magnesium chloride, and 5 g of purified water The turtle was added and mixed evenly. This was placed in a plastic tank and stored for 12 months. When this bagasse was defibrated with a disc refiner, coarse pulp with a hunter brightness of 67.3%, a tear length of 2.8 km, a specific burst strength of 1.7 and a specific tear strength of 45 was obtained. Was. The absolute dry pulp yield from the absolutely dry raw material was 83.2%. ADVANTAGE OF THE INVENTION According to the storage method and the transport method of this invention, even if it does not add a well-known preservative to a cellulosic material, it can be stored and transported without spoiling for a long period of time. Therefore, according to this method, storage costs and transportation costs are reduced, and problems such as environmental pollution due to the use of stored raw materials do not occur. According to this method, even in a high-temperature environment such as tropical or subtropical conditions, cellulosic substances can be stored for a long time in a warehouse without a temperature controller, and tropical or subtropical cell-based substances can be stored in a normal freight car. No problems such as decay or odor occur even when transported for a long time by freighter or freighter. Therefore, it is very suitable for storing and transporting agricultural wastes produced in the tropics or subtropics such as bagasse and banana leaves.

The cellulosic material stored for a long time or transported for a long time according to the method of the present invention is such that non-cellulosic materials such as lignin and resin contained in the raw material are gradually solubilized and removed during storage and transport. When the raw material is used as pulp, the time and cost of the pulping process are greatly reduced.

Claims

The scope of the claims

(1) A method for storing and transporting a cellulosic substance, which comprises storing or transporting the cellulosic substance while being in contact with an alkaline substance.

(2) A method for storing and transporting a cellulosic material, wherein the cellulosic material is stored or transported while being in contact with an alkaline substance and hydrogen peroxide.

(3) The method according to (1) or (2), wherein the cellulosic material is sand and canola or rice straw.

(4) The use of cellulosic substances stored or transported by the method described in any one of claims (1) to (3), and mechanical and / or chemical treatment of the defibrillation. Characteristic pulp manufacturing method.