JP4666378B2 - Decomposition method for woody waste - Google Patents

Description

  The present invention relates to the treatment of wood-based waste materials. More specifically, the waste material pulverized powder is brought into contact with a mixture of supercritical or subcritical water and a non-aqueous solvent that remains liquid at room temperature. The present invention relates to a method for decomposing a wood-based waste material.

  Energy development other than fossil fuels, such as biomass energy and solar energy, has been rapidly progressing toward the maintenance of the global environment and the realization of a sustainable society in contrast to the conventional development that has used fossil fuels such as oil and coal. It has been broken.

  Also, from the viewpoint of protecting the global environment, there are many problems with waste, such as a shortage of waste disposal sites and reuse / recycling of waste.

  Under such circumstances, there is a strong demand for the development of recycling technology for wood-based waste materials generated from bark, thinned wood, pruned branches, building waste, and the like. In addition to the above-mentioned building waste materials, wooden waste materials such as palm coconut shell waste, waste leaves and stems that are cultivated in Southeast Asia are also generated in large quantities. It is rare.

  As a decomposition treatment method of woody waste materials, biological decomposition by fungi and chemical decomposition by acid, alkali, etc. have been studied a lot. Recently, various treatments by high-temperature high-pressure water have been studied.

Particularly recently, many decomposition methods using supercritical fluids have been proposed. For example, in Patent Document 1, high-speed saccharification of wood with supercritical water or subcritical water, Patent Document 2 is a method of decomposing plant-derived waste with supercritical water or subcritical water, Patent Document 3 is lignocellulose or cellulose, A method of treating nitrogen-containing polysaccharides and proteins with supercritical alcohols and subcritical alcohols has been proposed.
JP 2005-206468 A JP 2005-81332 A JP 2001-205070 A

  From the viewpoints of energy problems and environmental problems, many woody waste decomposition methods have been studied, but there are problems with processing speed and efficient processing techniques and throughput on an industrial scale.

  Furthermore, chemical decomposition with acid / alkali requires steps such as liquid separation and liquid management after the decomposition treatment, and secondary treatment of the liquid, which requires a large amount of energy and causes further environmental problems. There is a possibility.

  The decomposition process using a supercritical fluid can be performed in a short time. However, in the case of treatment with water, it is necessary to separate and recover the treated decomposition product from water, and a step such as mixing with a solvent is required. In the case of treatment with an alcohol system such as a supercritical alcohol, the reaction is generally slower than that of a supercritical water system, but the alcohol is considered to be more useful because it is in a supercritical state at a lower temperature and lower pressure than water. On the other hand, when the supercritical treatment is performed with an alcohol system, it is difficult to extract the oil-soluble component using a non-aqueous solvent. This is because the alcohol system is compatible with the non-water-soluble solvent.

  In view of the disadvantages of the conventional methods as described above, an object of the present invention is to provide a method for easily decomposing and separating wooden waste materials at low cost.

The present invention heats the pulverized powder of a wood-based waste material to be decomposed, a water-insoluble solvent, and water to bring at least one of the water-insoluble solvent and water into a subcritical or supercritical state. Is then separated into a non-aqueous solvent containing the first decomposition product of the wooden waste material and water containing the second decomposition product of the wooden waste material. The water-soluble solvent separates the first decomposition product by volatilizing the non-water-soluble solvent or distillation operation, and the decomposition product contained in water removes the second decomposition product by volatilizing water or distillation operation. It is characterized by separating. In addition, a compound having 2 to 20 carbon atoms and keeping a liquid state at room temperature is used as the water-insoluble solvent.

  Note that the average particle size of the pulverized powder is preferably 1 mm or less in order to improve the decomposition efficiency.

  The present invention is a main component of wood waste by treating with a mixture of water-insoluble solvent and water in which the pulverized powder of wood waste is in a supercritical state or subcritical state. Decomposes degradation products such as cellulose, hemicellulose, and lignin. Of the above decomposed products, a hardly water-soluble decomposed product is dissolved in a supercritical non-aqueous solvent. A water-insoluble solvent is incompatible with water and easily separated from water due to the difference in specific gravity. Therefore, it is easy to separate the liquid, and the solvent after separation can be volatilized and used as a new raw material. Recovery of decomposition products is facilitated. In addition, environmental considerations are possible by re-collecting and using the solvent.

  The wood-based waste material used in the present invention can be decomposed by any wood waste material, and wood-based waste materials generated from such thinned wood, bark, and pruned branches of cedar and birch, as well as from such construction waste materials are also decomposed it can. Further, any kind of palm coconut shell waste, waste leaves, and stems, which are often cultivated in Southeast Asia, may be used.

  The main components of such wood-based waste materials are cellulose, hemicellulose, and lignin. In the present invention, by changing the decomposition treatment conditions such as temperature, pressure, treatment time, etc., which components are decomposed to what extent. Can be adjusted.

  However, the wood-based waste material provided for the present invention needs to be pulverized before the decomposition treatment. The pulverized particle size is desirably as fine as possible, and preferably 1 mm or less. If the pulverized particle size is large, the decomposition takes a long time and may not be sufficiently decomposed. For pulverization, the water content of the wood-based waste material should be as low as possible, preferably 50% or less. Therefore, depending on the type of waste material, it may be better to perform a drying process in advance.

  For the pulverization process, a general pulverization apparatus such as a crusher, a cutter mill, a disk mill, etc. can be used in combination.

  The alkyl compound group and the aromatic alkyl compound group used in the present invention are preferably at least one solvent selected from the group consisting of pentane, hexane, toluene and the like. In addition, these alkyl compounds and alkyl compounds containing aromatics may be one kind or a mixture of two or more kinds.

The alkyl compound of the present invention and the alkyl compound containing aromatics are determined by the type and amount of the wood-based waste material to be treated, but if the amount is too small, it becomes difficult to dissolve the decomposition products generated by the decomposition of the waste material, and if too much, Since the treatment process and time of the liquid after the liquid separation increase, it is necessary to select an appropriate amount.

Further, the treatment temperature and pressure are preferably equal to or higher than the temperature and pressure at which the alkyl compound group and the aromatic alkyl-containing compound group become subcritical or supercritical.
The critical temperature of pentane is 469.7K, the critical pressure is 33.7MPa, the critical temperature of hexane is 507.5K, the critical pressure is 30.1MPa, the critical temperature of toluene is 591.8K, and the critical pressure is 41.0MPa.

  In the treatment method of the present invention, after the decomposition and decomposition treatment of the wood-based waste material, the subcritical or supercritical water is added with the subcritical or supercritical alkyl compound group and the aromatic alkyl compound group. The product can be easily separated and recovered.

  In the treatment method of the present invention, for example, first, the wood waste material to be decomposed is pulverized by a pulverizer or the like. Next, the pulverized powder, water, and a water-insoluble solvent are placed in a pressure vessel. Next, the pressure vessel is heated to adjust the water and the non-aqueous solvent to a subcritical or supercritical state, and a treatment for several seconds to several tens of minutes is performed. Through this treatment, cellulose, hemicellulose, and lignin in the woody waste powder are decomposed into their low molecular compounds, monomers, oligomers, and the like. Thereafter, the pressure vessel is returned to normal temperature and pressure and opened to separate water and the non-aqueous solvent by specific gravity. Furthermore, the decomposition product and the water-insoluble solvent are separated by volatilizing the water-insoluble solvent or by a distillation operation. In addition, decomposition products contained in water are similarly separated by volatilization or distillation. Further, in the case of a solid component that does not dissolve in water or a non-aqueous solvent, it can be easily separated by filtration or the like.

  Hereinafter, the present invention will be described in more detail with reference to specific examples.

  In this example, a palm palm waste trunk cut into a plate shape of 200 × 300 × 50 mm was used as the wood-based waste material.

  This palm palm trunk was coarsely pulverized to a few millimeters with a cutter mill VM-22 manufactured by Sugano Sangyo Co., Ltd. equipped with a 10 mm screen. Next, the coarsely pulverized product was further pulverized by a fine pulverizer DD-2-3.7 manufactured by Hadano Sangyo. The screen used was Φ0.35 mm. As a result, a fine powder having an average particle size of about 0.15 mm was obtained.

  0.4 g of this fine powder was put in a heat-resistant / pressure-resistant container, and about 10 ml of toluene and about 10 ml of water were added. The heat-resistant / pressure-resistant container was placed in a high-temperature bath and heated to 350 ° C. and treated for 1 minute. Moreover, the sample processed for 30 minutes and 1 hour on the same conditions was also created.

  Thereafter, the heat and pressure resistant container was transferred to a water bath and cooled to room temperature, and then the heat and pressure resistant container was opened and returned to normal pressure.

  When treated for 1 minute, a slight residue and a dark brown liquid remained, but when treated for 30 minutes or more, almost no solid matter was found and only liquid was obtained. The slight residue was filtered through filter paper to separate the liquid and solid. Further, the liquid was separated into an aqueous phase and a toluene phase, and each was analyzed by high performance liquid chromatography.

Compared to the aqueous phase, the toluene phase contained a lot of poorly water-soluble decomposition products. It was found that the liquid treated for 30 minutes or more compared with the case of treating for 1 minute contains a large amount of organic acid such as acetic acid as the decomposition product.

  From this result, it was found that by treating under the above conditions, the aqueous phase and the toluene phase are in a state in which different decomposition product components are dissolved. In particular, it was confirmed that the toluene phase contained degradation products derived from poorly water-soluble lignin, and useful degradation products could be efficiently extracted together with the degradation treatment.

  Further, insoluble components can be separated and recovered from the liquid phase by filtering with a filter paper before liquid separation.

  In this example, a palm palm waste trunk pulverized by the same method as in Example 1 was used as the wooden waste material.

  The treatment was performed for 1 minute under the same conditions as in Example 1 except that hexane was used as the non-aqueous solvent and the treatment temperature was changed to 180 ° C., 240 ° C., and 280 ° C. with water added.

  As a result, at 180 ° C., the pulverized powder hardly changed, and about 80% of a residue and a light yellow liquid were obtained. About 240% residue and a dark yellow liquid are obtained at 240 ° C., about 20% residue and a dark brown liquid are obtained at 280 ° C., and a slight residue almost the same as in Example 1 is obtained at 350 ° C. A dark brown liquid was obtained. These residues were separated by filter paper, and the liquid was analyzed in the same manner as in Example 1.

  When treated at 180 ° C, both aqueous phase and toluene phase contain coniferyl alcohol, p-coumaryl alcohol, monosaccharides, sugar degradation products, etc., but the treatment temperature is low and the decomposition treatment is not progressing. I understand. On the other hand, the liquid treated at 240 ° C. has more low-molecular components and oligomers such as poorly water-soluble lignin than the aqueous phase, and contains lignin-derived degradation products such as coniferyl alcohol and p-coumaryl alcohol. It was. Further, the liquid treated at 280 ° C. contained a lot of coniferyl alcohol, p-coumaryl alcohol, sugar decomposition products and the like as in Example 1.

As described above, according to the present invention, it is possible to easily decompose a wood-based waste material that has a great influence on the environment, and to easily recover a product after the decomposition. Furthermore, since the waste liquid after the treatment can be easily treated, the apparatus can be greatly simplified and industrially effective as compared with the conventional method using supercritical water or subcritical water.

Claims (3)

The wood waste material ground powder to be decomposed, the water-insoluble solvent and water are heated, and at least one of the water-insoluble solvent and water is brought into a subcritical or supercritical state. Disassemble,
After that, it is separated into a water-insoluble solvent containing the first decomposition product of the wooden waste material and water containing the second decomposition product of the wooden waste material,
The decomposition product and the non-aqueous solvent are separated from the first decomposition product by volatilizing the non-aqueous solvent or by distillation operation,
A method for decomposing a wooden waste material, wherein a decomposition product contained in water is volatilized and the second decomposition product is separated by distillation operation . The method for decomposing a wood-based waste material according to claim 1, wherein an average particle size of the pulverized powder is 1 mm or less. The method for decomposing a wooden waste material according to claim 1 or 2 , wherein a compound having 2 to 20 carbon atoms and maintaining a liquid state at room temperature is used as the non-aqueous solvent.