JP2017100382A - Method for producing pellet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a pulp obtained by using lignocellulose as a raw material as a pellet having good formability without adding or heating a binder such as a resin.SOLUTION: A production method that produces a pellet containing a pulp includes a step of adjusting a pulp produced by using a lignocellulose material as a raw material so that a moisture percentage is 10 mass% or more and 35 mass%, and a step of pelletizing the pulp which has been adjusted so that the moisture percentage is 10 mass% or more and 35 mass% by solid-liquid separation with a pressurized solid-liquid separator.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing pellets containing pulp.

  Biomass represented by wood is attracting attention as an industrial resource. Biomass means a material derived from a living organism such as a plant.

  Under these circumstances, blending biomass into resin molded products that are widely used from automotive parts materials to daily necessities promotes the practice of the carbon neutral philosophy, and the most abundant wood as biomass is used for molding. Use as a material or compounding with other resin materials is consistent with the recent promotion of the environmental circulation cycle.

  However, when untreated wood is pulverized as it is, the moldability is insufficient and mixing with other thermoplastic resins is difficult. Therefore, in Patent Document 1, a woody material is heated and pressurized in the presence of water vapor, and then mixed with a powdery explosion material, a resin, and a powdery woody material obtained by abrupt decompression and explosion. Patent Document 2 describes a method for producing a wood-based molded body by performing steam treatment on a lignocellulose-containing material to obtain a powder having a particle size of 45 μm or more and 180 μm or less. In addition, these biomass materials are often used as pellets for easy handling before being formed by an extruder or the like.

  In addition, the use of pelletized biomass as a fuel has been studied, and Patent Document 3 discloses a method of pelletizing wood powder and cedar leaf powder at 40 to 60 ° C. for 2 to 5 hours. Have been described. Patent Document 4 describes a method of molding biomass subjected to steam explosion treatment into pellets.

JP 2006-272696 A JP 2003-165844 A JP 2012-116973 A Special table 2012-512270 gazette

  However, pulp having delignified progress, such as kraft pulp, is difficult to be pelletized because the content of thermoplastic lignin is small. Since Patent Document 1 contains a large amount of untreated powdery woody material, the moldability is insufficient, and the lignocellulosic thermoplastic material of Patent Document 2 is also insufficient in terms of moldability.

  Then, the subject of this invention is providing the method of manufacturing easily the pulp obtained from lignocellulose as a raw material as a pellet with favorable moldability, without adding binders, such as resin.

The inventors of the present invention have intensively studied the above problems, and found that the above problems can be solved by adjusting the moisture content of the pulp produced using the lignocellulosic material as a raw material, and the present invention has been completed. .
(1) A method for producing a pellet containing pulp, the step of adjusting a pulp produced using a lignocellulosic material as a raw material to a moisture content of 10% by mass to 35% by mass, a moisture content of 10% by mass to 35% by mass A process for pelletizing the conditioned pulp.
(2) A method for producing a pellet containing pulp, the step of obtaining pulp in a liquid using a lignocellulosic material as a raw material, the obtained pulp is solid-liquid separated by a pressure-type solid-liquid separator, and the moisture content Including the step of making 15% by mass or more and 35% by mass or less, the step of pelletizing the pulp having a moisture content of 15% by mass or more and 35% by mass or less, the step of preparing pellets containing solid-liquid separated pulp, Method.
(3) The method according to (2), wherein washing with water is simultaneously performed when the pulp is solid-liquid separated by a pressure-type solid-liquid separator.
(4) The method according to any one of (2) to (3), wherein the pressure-type solid-liquid separator is one or more of a screw press, a filter press, a roll press, and a wash press.
(5) The method according to any one of (2) to (4), wherein the moisture content of the pulp before solid-liquid separation treatment is performed in a pressurized solid-liquid separator is 50% by mass or more and 99% by mass or less.
(6) The method according to any one of (1) to (5), wherein a pellet having a pellet diameter of 4 to 8 mm is produced in the pelletizing step.
(7) The method according to any one of (1) to (7), wherein the pulp is kraft pulp.

  According to the present invention, it is possible to easily pelletize a pulp made from lignocellulose without adding a binder such as a resin or heating. Moreover, handling and transportability can be improved by pelletizing.

  The pellets produced in the present invention are produced from pulp adjusted to a moisture content of 10% by mass to 35% by mass using a lignocellulosic material as a raw material. By adjusting the moisture content of the pulp to 10% by mass or more and 35% by mass or less, the fiber-to-fiber bond is appropriately formed, so that a good pellet can be produced. In order to set the moisture content to 10% by mass or more and 35% by mass or less, for example, after lignocellulose raw material is pulped in a liquid, solid-liquid separation is performed in a dehydration step using a pressure-type solid-liquid separation device. If the moisture content is less than 10% by mass, it will be excessively dehydrated and the pulp fibers will be too tight, making it difficult to pelletize. On the other hand, when the moisture content exceeds 35% by mass, it becomes easy to be crushed and it becomes difficult to form a pellet. In addition, when the moisture content of a pulp exceeds 35 mass% by the process by a pressurization type solid-liquid separator, you may adjust a moisture content to 10 mass% or more and 35 mass% or less by air drying or drying with a hot air. The moisture content is calculated by the following equation: moisture content (mass%) = (A−B) / A (A: pulp mass before drying, B: pulp mass after absolutely dried).

  The pressure-type solid-liquid separator is not particularly limited as long as it can be adjusted to a moisture content of 10% by mass or more and 35% by mass or less, but is usually a screw press, a filter press, which is also used as a washing machine in a pulp manufacturing process. Either a roll press or a wash press, or a combination thereof can be used.

  Prior to pelletization, the pulp may be fluffed, that is, the pulp may be defibrated by mechanical treatment. Although the apparatus used for fluffing is not particularly limited, a known defibrator used for manufacturing absorbent materials such as paper diapers can be used, and a defibrator utilizing frictional force or shearing force as a mechanical treatment Can be suitably used. As an apparatus used for fluffing, for example, a defibrating apparatus having a toothed cylinder can be suitably used (see Japanese Patent No. 2521577).

  There are no particular limitations on the apparatus for performing compression molding to form pellets, but Briquetter (made by Kitagawa Iron Works Co., Ltd.), ring die type pelletizer (made by CPM Co., Ltd.), flat die type pelletizer (Dalton ( Etc.) are desirable.

  The pulp which is the object of the present invention is a pulp produced by various known pulping methods using lignocellulose as a raw material. For example, both mechanical pulp and chemical pulp are applicable. Examples of mechanical pulp include groundwood pulp (GP), refiner groundwood pulp (RGP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), and the like. Examples of the chemical pulp include kraft pulp (KP), dissolved kraft pulp (DKP), sulfite pulp (SP), and dissolved sulfite pulp (DSP). Either bleached pulp or unbleached pulp can be used. Of these, kraft pulp is preferred.

  In the present invention, the pulp may consist of one kind or may be a mixture of a plurality of pulps. For example, chemical pulps (hardwood kraft pulp, softwood kraft pulp, hardwood melted kraft pulp, softwood melted kraft pulp) or mechanical pulp (crushed wood pulp, refiner groundwood pulp, thermomechanical pulp, chemithermomechanical pulp with different raw materials and production methods ) May be used in combination of two or more.

  As the raw material wood, for example, hardwood, conifer, miscellaneous tree, bamboo, kenaf, bagasse, empty bunch after palm oil extraction can be used. Specifically, the broad-leaved trees include beech, china, birch, poplar, eucalyptus, acacia, oak, itayaka maple, senoki, elm, giraffe, honoki, willow, sen, basamushi, konara, kunugi, tochinoki, zelkova, mizume, mizuzuki Aodamo etc. are exemplified. As conifers, cedar, spruce, larch, black pine, todomatsu, himekomatsu, yew, neko, spruce, iramimi, fir, sawara, togasawara, asunaro, hiba, tsuga, kotsutsuga, hinoki, yew, yellowtail, spruce (Beihiba), Lawson Hinoki (Beihi), Douglas Fir (Beimatsu), Sitka Spruce (Beisuhi), Radiata Pine, Eastern Spruce, Eastern White Pine, Western Larch, Western Fir, Western Hemlock, Tamarack and the like.

Kraft pulp The pulp in the present invention includes kraft pulp in a preferred embodiment, and particularly preferably includes wood-derived kraft pulp. The copper number of kraft pulp is preferably 40 or less, more preferably 20 or less, and particularly preferably 10 or less. The ISO whiteness is not particularly limited, but the ISO whiteness is preferably 30% or more, more preferably 40% or more, and particularly preferably 50% or more.

  When manufacturing kraft pulp from wood chips, the wood pulp is put into a digester together with the cooking liquor and used for kraft cooking. Moreover, you may use for cooking of correction craft methods, such as MCC, EMCC, ITC, and Lo-solid. Also, there are no particular limitations on cooking types such as 1 vessel liquid phase type, 1 vessel gas phase / liquid phase type, 2 vessel liquid phase / gas phase type, and 2 vessel liquid phase type. That is, the step of impregnating and holding the alkaline aqueous solution of the present application may be installed separately from the conventional apparatus or part for the permeation treatment of the cooking liquid. Preferably, the unbleached pulp that has been cooked is washed with a washing device such as a diffusion washer after extracting the cooking liquor.

  The craft cooking process can be performed by putting wood chips in a pressure resistant container together with the kraft cooking liquid, but the shape and size of the container are not particularly limited. The liquid ratio between the wood chip and the chemical solution can be, for example, 1.0 to 5.0 L / kg, preferably 1.5 to 4.5 L / kg, and more preferably 2.0 to 4.0 L / kg. .

  Further, in the present invention, 0.01 to 1.5% by mass of a quinone compound per absolutely dry chip for the purpose of lowering the pulp kappa number, improving the pulp yield, reducing wrinkles, suppressing the decrease in pulp viscosity, etc. Alkaline cooking liquor containing may be added to the digester. If the addition amount of the quinone compound is less than 0.01% by mass, the addition amount is too small to reduce the kappa number of the pulp after cooking, and the relationship between the kappa number and the pulp yield is not improved. Furthermore, the reduction of wrinkles and the suppression of the decrease in viscosity are insufficient. Moreover, even if the addition amount of a quinone compound exceeds 1.5 mass%, the further reduction of the kappa number of the pulp after cooking and the improvement of the relationship between a kappa number and a pulp yield are not recognized.

  The quinone compound used is a quinone compound, hydroquinone compound or precursor thereof as a so-called known cooking aid, and at least one compound selected from these can be used. Examples of these compounds include anthraquinone, dihydroanthraquinone (for example, 1,4-dihydroanthraquinone), tetrahydroanthraquinone (for example, 1,4,4a, 9a-tetrahydroanthraquinone, 1,2,3,4-tetrahydroanthraquinone). Methyl anthraquinone (eg 1-methyl anthraquinone, 2-methyl anthraquinone), methyl dihydroanthraquinone (eg 2-methyl-1,4-dihydroanthraquinone), methyl tetrahydroanthraquinone (eg 1-methyl-1,4,4a) , 9a-tetrahydroanthraquinone, 2-methyl-1,4,4a, 9a-tetrahydroanthraquinone) and the like, anthrahydroquinone (generally 9,10-dihydroxyanthracene), Tyranthrahydroquinone (for example, 2-methylanthrahydroquinone), dihydroanthrahydroanthraquinone (for example, 1,4-dihydro-9,10-dihydroxyanthracene) or an alkali metal salt thereof (for example, disodium salt of anthrahydroquinone, 1 , 4-dihydro-9,10-dihydroxyanthracene disodium salt), and precursors such as anthrone, anthranol, methylanthrone, and methylanthranol. These precursors have the potential to convert to quinone compounds or hydroquinone compounds under cooking conditions.

When the wood chip is a conifer, the cooking solution preferably has an active alkali addition rate (AA) per weight of the dry wood chip of 16 to 22% by mass. If the active alkali addition rate is less than 16% by mass, the removal of lignin and hemilulose becomes insufficient. Here, the active alkali addition rate is obtained by converting the total addition rate of NaOH and Na ₂ S as the addition rate of Na ₂ O, and multiplying NaOH by 0.775 and Na ₂ S by 0.795. Therefore, it can be converted into the addition rate of Na ₂ O. The degree of sulfidation is preferably in the range of 20 to 35%. In the region where the sulfidity is less than 20%, the delignification property is lowered, the pulp viscosity is lowered, and the drought rate is increased.

  Kraft cooking is preferably performed in a temperature range of 120 to 180 ° C, more preferably 140 to 160 ° C. If the temperature is too low, delignification (decrease in the kappa number) is insufficient, while if the temperature is too high, the degree of polymerization (viscosity) of cellulose decreases. The cooking time in the present invention is the time from when the cooking temperature reaches the maximum temperature until the temperature starts to decrease, and the cooking time is preferably 60 minutes or more and 600 minutes or less, and 120 minutes or more and 360 minutes or less. Is more preferable. If the cooking time is less than 60 minutes, pulping does not proceed, and if it exceeds 600 minutes, the pulp production efficiency deteriorates, which is not preferable.

  Moreover, the kraft cooking in this invention can set process temperature and process time by setting H factor (Hf) as a parameter | index. The H factor is a standard representing the total amount of heat given to the reaction system during the cooking process, and is represented by the following equation. The H factor is calculated by time integration from the time when chips and water are mixed until the end of cooking.

Hf = ∫exp (43.20-16113 / T) dt
[Wherein T represents an absolute temperature at a certain point]
In the present invention, the unbleached (unbleached) pulp obtained after cooking can be subjected to various treatments as necessary. For example, bleaching can be performed on unbleached pulp obtained after kraft cooking.

  The pulp obtained by kraft cooking can be subjected to oxygen delignification treatment. As the oxygen delignification used in the present invention, a known medium concentration method or high concentration method can be applied as it is. In the case of the medium concentration method, the pulp concentration is preferably 8 to 15% by mass, and in the case of the high concentration method, it is preferably performed at 20 to 35% by mass. As the alkali in oxygen delignification, sodium hydroxide and potassium hydroxide can be used. As oxygen gas, oxygen from a cryogenic separation method, oxygen from PSA (Pressure Swing Adsorption), VSA (Vacuum Swing Adsorption) Oxygen etc. from) can be used.

The reaction conditions for the oxygen delignification treatment are not particularly limited, but the oxygen pressure is 3 to 9 kg / cm ² , more preferably 4 to 7 kg / cm ² , the alkali addition rate is 0.5 to 4% by mass, and the temperature is 80%. ~ 140 ° C, treatment time is 20 to 180 minutes, and other conditions can be applied. In the present invention, the oxygen delignification treatment may be performed a plurality of times.

  When further reducing the kappa number and improving the whiteness, the pulp that has been subjected to oxygen delignification treatment, for example, is then sent to the washing step, and then sent to the multistage bleaching step after washing to perform the multistage bleaching treatment. Can do. The multi-stage bleaching treatment of the present invention is not particularly limited, but acid (A), chlorine dioxide (D), alkali (E), oxygen (O), hydrogen peroxide (P), ozone (Z), It is preferable to combine a known bleaching agent such as peracid and a bleaching aid. For example, the first stage of the multistage bleaching process uses a chlorine dioxide bleaching stage (D) or an ozone bleaching stage (Z), the second stage is an alkali extraction stage (E), the hydrogen peroxide stage (P), the third stage or later. A bleaching sequence using chlorine dioxide or hydrogen peroxide is preferably used. The number of stages after the third stage is not particularly limited, but considering energy efficiency, productivity, etc., it is preferable to finish in three or four stages in total. Further, a chelating agent treatment stage with ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA) or the like may be inserted during the multistage bleaching treatment.

  The pellets of the present invention may comprise a pulp content of 100% by mass, but other components may be blended as necessary when pelletized. At that time, the pulp content is preferably 80% by mass or more, and more preferably 90% by mass or more. Other components include polypropylene (PP), polyethylene (PE), polystyrene, polymethyl methacrylate, vinyl chloride, polyamide (nylon), polycarbonate, polyacetal, polybutylene terephthalate, polyethylene terephthalate (PET), and other thermoplastic resins. , Phenolic resin, urea resin, melamine resin, unsaturated polyester resin, thermosetting resin such as epoxy resin, natural water-soluble polymer such as starch, modified starch, carboxymethylcellulose, casein, polyvinyl alcohol, polyacrylamide, polyacrylic acid Synthetic water-soluble polymers such as calcium carbonate, clay, silica, titanium oxide and other inorganic fillers, antibacterial agents and the like. In addition, when the pellets of the present invention are used as feed, roughage (for example, pasture), concentrated feed (for example, grains such as corn and wheat, beans such as soybean), bran, rice bran, okara, protein, lipid, vitamin, mineral And additives (preservatives, coloring agents, fragrances, etc.) and the like.

  The pellet of the present invention preferably has a moisture content of 15% or less. By making the moisture content 15% or less, the transportability is improved and the decay by microorganisms can be reduced.

  The pellet of the present invention preferably has a pellet diameter of 4 to 8 mm. In addition to being used as solid fuel and feed as it is, the pellets can be supplied together with a resin to an extrusion molding machine, an injection molding machine or the like to form a molding material.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited by these. In addition,% in an Example and a comparative example shows the mass% unless there is particular notice.

[Example 1]
Unbleached hardwood kraft pulp sheet after oxygen delignification (water content: 50.2%, copper number: 9.2, whiteness: 44.7) defibrating machine (trade name: wet pulp defibrating machine, Kumagai Riki Kogyo Co., Ltd.) Was defibrated, and fluff-shaped hardwood unbleached fluff pulp was obtained. The obtained hardwood unbleached fluff pulp was dried indoors in a well-ventilated place to adjust the moisture content to 17.9%. Next, it was processed with a ring die type small pelletizer (manufactured by California Pellet Mill, motor capacity 30 kW) to obtain pulp pellets. The pellets obtained had a moisture content of 13.9%.

[Example 2]
Pulp pellets were obtained in the same manner as in Example 1 except that the moisture content of the hardwood unbleached fluff pulp was adjusted to 29.6%. The obtained pellet had a moisture content of 26.7%.

[Example 3]
Pulp pellets were obtained in the same manner as in Example 1 except that the moisture content of the hardwood unbleached fluff pulp was adjusted to 32.8%. The pellets obtained had a moisture content of 29.5%.

[Example 4]
The hardwood unbleached fluff pulp obtained in Example 1 was pressed using a screw press (manufactured by Togoku Industry). A screw press having a length of 800 mm from the raw material inlet to the outlet was used. The raw material was input manually, the rotational speed of the screw shaft was set to 6 rpm / min, and the hardwood unbleached fluff pulp was processed at a processing speed of about 10 to 20 kg / h. In order to increase the squeezing force, the clearance at the outlet was treated with a minimum of 7.7 mm. The moisture content of the obtained pulp was 30.1%.
Subsequently, hardwood unbleached fluff pulp was put into a ring die type small pelletizer (motor capacity 30 kW) of the same type as in Example 1 to obtain hardwood unbleached kraft pulp pellets. The obtained pellets had a moisture content of 28.0%.

[Comparative Example 1]
Pulp pellets were obtained in the same manner as in Example 1 except that the moisture content of the hardwood unbleached fluff pulp was adjusted to 9.7%. The pellets obtained had a moisture content of 8.1%.

[Comparative Example 2]
Pulp pellets were obtained in the same manner as in Example 1 except that the moisture content of the hardwood unbleached fluff pulp was adjusted to 45.5%. The pellets obtained had a moisture content of 42.1%.

  In Examples 1-4 and Comparative Examples 1-2, the quality of the pellet moldability was evaluated, and the results are shown in Table 1. The quality of the pellet moldability was judged by observing the presence or absence of cracks in the pellet and the presence or absence of gloss on the pellet surface with the naked eye. A pellet having no crack and having gloss on the pellet surface had the best moldability.

  As shown in Table 1, the hardwood unbleached fluff pulp in which the moisture content of Examples 1 to 4 was adjusted to 15 to 35% had good moldability. On the other hand, Comparative Example 1 having a moisture content of less than 15% and Comparative Example 2 having a moisture content exceeding 35% had poor moldability.

  As mentioned above, it discovered that a pulp pellet with favorable moldability was obtained by adjusting a pulp moisture content. It was also considered that pellets having good moldability could be obtained by mechanically compressing and dewatering the pulp and then pelletizing the pulp. According to the present invention, it was possible to successfully produce a pellet using pulp, to produce a pulp pellet with good transportability and economically.

The right of the photograph is the pulp pellet of Example 1, and the left is the pulp pellet of Comparative Example 2.

Claims (7)

A method for producing a pellet containing pulp,
A step of adjusting the pulp produced from the lignocellulosic material as a raw material to a moisture content of 10% by mass or more and 35% by mass;
A step of pelletizing pulp adjusted to a moisture content of 10% by mass or more and 35% by mass;
Including the above method. A method for producing a pellet containing pulp,
A process of obtaining pulp in a liquid using a lignocellulosic material as a raw material;
Solid-liquid separation of the obtained pulp with a pressure-type solid-liquid separator, and a moisture content of 15% by mass to 35% by mass;
A step of pelletizing a pulp having a moisture content of 15% by mass to 35% by mass;
Preparing a pellet containing solid-liquid separated pulp;
Including the above method.   The method according to claim 2, wherein washing with water is performed simultaneously with solid-liquid separation of the pulp with a pressurized solid-liquid separator.   The method according to any one of claims 2 to 3, wherein the pressure-type solid-liquid separator is one or more of a screw press, a filter press, a roll press, and a wash press.   The method according to any one of claims 2 to 4, wherein the moisture content of the pulp before solid-liquid separation treatment with a pressure-type solid-liquid separator is 50 mass% or more and 99 mass% or less.   The method according to any one of claims 1 to 5, wherein a pellet having a pellet diameter of 4 to 8 mm is produced in the pelletizing step.   The method according to claim 1, wherein the pulp is kraft pulp.

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