Essential oil extraction methods

Abstract

The present invention aims to effectively utilize peeled cores and provides a new and useful method for extracting essential oils. [Solution] This essential oil extraction method comprises the following steps: a preparation step of preparing the peeled core 4 remaining after cutting a log 1 to continuously obtain veneers 3; a crushing step of crushing the peeled core to obtain a crushed material; a distillation step of distilling the crushed material to obtain a distillate; and a separation step of separating the distillate into essential oil and aromatic distilled water. It is preferable that the method further comprises a water removal step of removing minute amounts of water contained in the essential oil obtained in the separation step. The essential oil obtained by this method can be used in the same applications as conventional methods, and the crushed material after essential oil extraction can be reused alone or mixed with other materials in the production of wood fiberboards such as MDF and wood boards such as particle board.

Description

[Technical Field]

[0001] The present invention relates to a method for extracting essential oils from wood. [Background technology]

[0002] Wood, especially coniferous wood such as cypress, contains many phytoncides, which are aromatic compounds known to have medical effects such as stress relief, vitality restoration, and improvement of depression. Furthermore, it has also been reported to have antibacterial, insecticidal, and deodorizing effects.

[0003] As a method for achieving such effects, the extraction of essential oils from trees such as Japanese cypress is disclosed in the following Patent Documents 1 and 2. Patent Document 1 discloses a method for extracting essential oils from Japanese cypress materials consisting of Japanese cypress trunks, leaves, or nuts. Patent Document 2 discloses a method for extracting essential oils from Japanese cypress root stumps.

[0004] The general method for manufacturing plywood involves stripping the bark from logs and cutting them to a specified length (e.g., 2000-2150 mm), steaming them as needed (especially in the case of coniferous logs), and then centering them using a centering device, cutting them into thin veneers (green veneers) a few millimeters thick using a stripping method. These are then dried to a specified moisture content and cut to specified dimensions, stacked with the fibers perpendicular to each other, and hot-pressed to produce plywood (see Figures 1 and 2). A rotary lathe is mainly used to strip the bark from logs and cut them into veneers, but after cutting into veneers using the rotary lathe, long cylindrical rods (stripped cores) about 50 mm in diameter inevitably remain. Currently, peeled core is crushed into chips and used as a raw material for producing wood boards such as MDF (medium density fiberboard), as a raw material for cardboard, to protect seedlings in seawalls, or as biomass fuel, but this has not been enough to make effective use of the large amount of peeled core that is generated during the plywood manufacturing process. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6829510 [Patent Document 2] Patent No. 7025804 Summary of the Invention [Problem to be solved by the invention]

[0006] In view of the above background, the inventors have focused on extracting essential oils from the peeled core, which remains after raw wood such as Japanese cypress is peeled to produce veneers in succession, as a novel and effective way of utilizing the peeled core. After extensive testing and consideration, they have completed the present invention.

[0007] In other words, the problem to be solved by the present invention is to make effective use of peeled cores and to provide a new and useful method for extracting essential oils. [Means for solving the problem]

[0008] In order to solve this problem, the invention of claim 1 of the present application is an essential oil extraction method characterized by comprising a preparation step of preparing the peeled core that remains after cutting a log to continuously obtain veneers, a crushing step of crushing the peeled core to obtain a crushed material, a distillation step of distilling the crushed material to obtain a distillate, and a separation step of separating the distillate into essential oil and aromatic distilled water.

[0009] The invention of claim 2 of the present application is characterized in that, in the essential oil extraction method described in claim 1, it further comprises a water removal step for removing minute amounts of water contained in the essential oil obtained in the separation step.

[0010] The invention of claim 3 of the present application is characterized in that, in the essential oil extraction method described in claim 2, the water removal process comprises a step of cooling the essential oil obtained in the separation process to a temperature below the freezing point of water and above the freezing point of the essential oil components, and then filtering it to remove frozen micro-water particles.

[0011] The invention of claim 4 of the present application is characterized in that, in the essential oil extraction method described in claim 1, the pulverized material obtained by the pulverization step is a thin, elongated pulverized material having dimensions of an average length of 10 to 30 mm, an average width of 3 to 10 mm, and an average thickness of 1 to 2 mm. [Effects of the Invention]

[0012] The large amount of peeled core that remains after the logs are peeled to produce continuous veneers has traditionally had limited uses, but the present invention provides a new use for the peeled core, thereby expanding the effective use of the peeled core. Furthermore, since the peeled core contains more essential oil than other parts of the logs, a high essential oil recovery rate can be achieved by extracting the essential oil from the peeled core.

[0013] Furthermore, in the present invention, a water removal step is carried out to remove minute amounts of water contained in the essential oil obtained in the separation step, thereby enabling extraction of a highly pure essential oil. In addition, the water removal step involves cooling the essential oil obtained in the separation step to a temperature below the freezing point of water but above the freezing point of the essential oil components, and then filtering the oil to remove the frozen minute amounts of water, thereby enabling the minute amounts of water contained in the essential oil to be removed efficiently in a short period of time.

[0014] In addition, in the present invention, the essential oil recovery efficiency can be further improved by using thin, elongated pulverized material having dimensions of an average length of 10 to 30 mm, an average width of 3 to 10 mm, and an average thickness of 1 to 2 mm as the pulverized material obtained by the pulverization process.

[0015] The essential oil obtained by the present invention can be used in the same applications as conventional ones, and the pulverized product after essential oil extraction can be reused as a single material or mixed with other materials in the production of wood fiberboards such as MDF and wood boards such as particle boards. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a flow chart showing the process of manufacturing plywood and the essential oil extraction method according to the present invention in the order of steps. [Figure 2] FIG. 1 is a side view showing the stripped core remaining after continuous veneer production using a rotary lathe. BEST MODE FOR CARRYING OUT THE INVENTION

[0017] The essential oil extraction method according to the present invention is described in detail below with reference to FIG.

[0018] (preparation process) Logs of coniferous trees such as cypress and cedar, or broad-leaved trees such as eucalyptus and camphor trees, are prepared. The species of the logs is not limited as long as essential oils can be extracted from them. The logs have a diameter of 160 to 500 mm and a length of 2000 to 2150 mm, for example.

[0019] This invention involves extracting essential oil from the core remaining after continuously obtaining veneers by peeling a log using a rotary lathe or similar method. Veneer cutting using a rotary lathe is well known, and as shown in Figure 1, thin veneers 3 are continuously produced by continuously cutting the log 3 in the same manner as peeling by pressing a cutting blade 2 against the surface of the log while rotating the log 1 around its cross-sectional center as an axis. The cross-sectional center that serves as the axis of rotation of the log 1 is the center of the inscribed circle calculated based on data obtained by measuring the cross-sectional shape of the log 1.

[0020] In this way, veneers are continuously obtained using a rotary lathe, leaving behind a long, cylindrical rod-shaped piece of peeled core 4. From a yield standpoint, it is preferable to produce veneers until the diameter of the peeled core is as small as possible. However, as the diameter of the log decreases, the resulting veneers become more warped, reducing their value as veneers. Therefore, generally, the diameter of the peeled core remaining at the end is about 50-60 mm, and its length is the same as the log, 2000-2150 mm.

[0021] (Crushing process) The peeled cores prepared in the preparation step are crushed using crushing means to obtain a crushed product. The crushing means is not limited as long as it can crush the peeled cores, and known cutting or crushing machines such as chippers, shredders, cutter mills (shear crushers), and flakers can be used. As an example, a large number of peeled cores are fed into a chipper and crushed into chips, resulting in crushed chips having an approximately rectangular flat plate shape (average length 25-40 mm, average width 25-40 mm, average thickness 3-5 mm). These crushed chips can then be crushed further using a shredder to obtain crushed chips having an approximately rectangular flat plate shape with an average length of 20-35 mm, average width 3-20 mm, and average thickness 3-5 mm. Alternatively, a large number of peeled cores can be put into a chipper and crushed into chips, resulting in roughly square, flat chips (average length 25-40 mm, average width 25-40 mm, average thickness 3-5 mm).The crushed chips can then be compressed, cut, and ground in a cutter mill (shear-type crusher) to produce thin, elongated pieces with an average length of 10-30 mm, average width of 3-10 mm, and average thickness of 1-2 mm.Alternatively, a large number of peeled cores can be crushed in a flaker to produce roughly square, flat pieces with an average length of 50-60 mm, average width of 50-60 mm, and average thickness of 1-1.5 mm.

[0022] (Distillation process) The crushed material obtained in the crushing step is distilled to obtain a liquid distillate (essential oil and water). The treatment method in the distillation step is not particularly limited, and it can be carried out using a commonly used distillation device. For example, the crushed material can be heated by steam distillation using heated steam, or by hot water distillation in which the crushed material is heated and boiled in water, and the gas generated during this process can be cooled using a cooling device or the like to obtain a distillate consisting of essential oil and water.

[0023] (separation process) The distillate obtained in the distillation process is separated into essential oil and water. The treatment method in the separation process is not particularly limited as long as it can separate the distillate into essential oil and water. For example, the distillate is separated into an essential oil layer and a water layer by leaving it to stand for a certain period of time or by performing a process such as re-distillation, and the essential oil layer can be recovered from that state. Furthermore, the water in the distillate is aromatic distilled water (aroma water) containing trace amounts of essential oil components, and can be recovered and used in air fresheners, lotions, etc. Note that if the essential oil and water are automatically separated and recovered during the distillation process, the separation process can be omitted.

[0024] (Water removal process) The essential oil separated and recovered in the separation step contains trace amounts of water, so a water removal step is preferably carried out to remove this water and obtain a highly pure essential oil. The water removal step is not particularly limited, as long as it can remove the minute amounts of water dispersed in the recovered essential oil. For example, the minute amounts of water in the essential oil can be frozen by cooling the essential oil to a temperature below the freezing point of water but above the freezing point of the essential oil components (e.g., about -20°C for cypress), and the frozen minute amounts of water can be removed by filtering the essential oil in this state. The amount of water contained in the essential oil can also be reduced by repeating the distillation multiple times in the distillation step or by leaving the distillate to stand for a long period of time in the separation step, but the freezing treatment described above allows the minute amounts of water in the essential oil to be removed efficiently in a short period of time.

[0025] The essential oils obtained as described above can be used for a variety of purposes (fragrances, cosmetics, antibacterial agents, insect repellents, deodorizers, detergents, aromatherapy, etc.) as they have effects such as relieving stress, restoring vitality, improving depression, antibacterial, insect repellent, and deodorizing, as in conventional techniques.

[0026] (Reuse process) The pulverized material remaining after essential oil extraction can be reused either as a standalone material or mixed with other materials in the manufacture of wood fiberboards such as MDF and wood-based boards such as particleboard.

[0027] The present invention will be specifically described below with reference to examples.

[0028] (preparation process) In this example, a cypress log from Shizuoka Prefecture (240 mm in diameter, 2100 mm in length) was used. The log was rotated in a rotary lathe and a cutting blade was applied to the surface to cut it into veneers. After this, many long cylindrical cores (50 mm in diameter, 2100 mm in length) were prepared. The veneer cutting was performed under the following conditions. Rotary Race: Rotation speed 145m / s Cutting blade: length 2200mm, tip thickness 0.5~16mm Veneer: 1.85mm thick

[0029] (Crushing process) After cutting the veneer, many of the peeled cores remaining were fed into a chipper and crushed into chips, roughly rectangular flat plates (average length 25-40mm, average width 25-40mm, average thickness 3-5mm). These were then compressed, cut, and crushed in a cutter mill (shear-type crusher) to obtain 36 kg of thin, elongated cypress crushed material with an average length of 20mm, average width of 5mm, and average thickness of 1.5mm.

[0030] (Distillation process) The cypress pulverized material obtained in the above grinding process was distilled using a steam distillation apparatus, the discharged steam was collected, cooled in a cooling apparatus, and the distilled water containing cypress essential oil was recovered in a recovery apparatus.

[0031] (separation process) The distilled water containing cypress essential oil, which was gradually recovered in the distillation process, was left standing in the recovery device as it was, and due to the difference in specific gravity between the cypress essential oil and the water, the upper layer became cypress essential oil and the lower layer became aromatic distilled water. 36 kg of cypress slab-like crushed material obtained in the crushing process was distilled and separated to obtain 450 mL of cypress essential oil and 60 L of aromatic distilled water.

[0032] (Water removal process) The cypress essential oil separated in the above separation process was cooled to a temperature below the freezing point of water but above the freezing point of the cypress essential oil (-18 to 20 degrees Celsius), freezing the minute water particles contained in the cypress essential oil. In this state, the cypress essential oil was filtered through a filter (mesh size 126-3) to remove the frozen minute water particles, yielding highly pure cypress essential oil. The size of the frozen minute water particles was 0.5 to 2 mm.

[0033] In the above examples, essential oils were extracted from the peeled cores that remain after cutting cypress logs with a rotary lathe to produce veneers. To demonstrate the advantages of using peeled cores as a material for essential oil extraction, the essential oil recovery rate (amount of essential oil extracted per weight of raw material) was tested when essential oil was extracted under different conditions. Each step was carried out under the same conditions as described in the examples unless otherwise specified.

[0034] First, in addition to the cypress used in the example, we also conducted a comparative test on the essential oil recovery rate when essential oil was extracted from the peeled heartwood of Japanese cedar (Sugi), and obtained the results shown in Table 1. From these results, it was confirmed that cypress yielded a better essential oil recovery rate than Japanese cedar as a raw wood species.

[0035] [Table 1]

[0036] Next, we conducted a comparative test of essential oil recovery rates when extracting essential oil from different parts of the cypress log, and obtained the results shown in Table 2. From these results, it was confirmed that using the peeled heartwood yielded the best essential oil recovery rate.

[0037] [Table 2]

[0038] Next, we conducted a comparative test of essential oil recovery rates when extracting essential oils from pulverized cypress logs with varying shapes and sizes of pulverized material. The results are shown in Table 3. These results indicate that the essential oil recovery rate was best when using pulverized material with a shape and size of approximately square flat chips obtained by pulverizing the chips in a chipper, followed by compressing, cutting, and grinding them in a cutter mill (shear mill). The best results were obtained when pulverized material with an average length of 20 mm, average width of 5 mm, and average thickness of 1.5 mm was used. Based on these results, we further performed essential oil extraction from pulverized material of various sizes. When pulverized material with an average length of 10-30 mm, average width of 3-10 mm, and average thickness of 1-2 mm was used, the essential oil recovery rate was approximately 1% or higher, confirming the efficient extraction of essential oils.

[0039] [Table 3]

[0040] The reason why the essential oil recovery rate is good when using elongated, thin, plate-shaped pulverized material obtained by further compressing, cutting, and grinding chip-shaped pulverized material obtained by cutting with a chipper is that it has a shape and dimensions that make it easy to extract essential oils, and in the process of further compressing, cutting, and grinding the chip-shaped pulverized material with a cutter mill (shear-type pulverizer), the essential oil is extracted and moves to the surface of the elongated, thin, plate-shaped pulverized material, where it is in a state that is easy to extract, and further cutting the chip-shaped pulverized material obtained by cutting with a chipper (which has a relatively smooth surface) The elongated, thin, plate-like pulverized material obtained by compressing, cutting, and grinding in a termiller (shear-type pulverizer) forms numerous microscopic irregularities on its surface. This increases the surface area of ​​each elongated, thin, plate-like pulverized material that comes into contact with water vapor. Furthermore, water vapor can spread through the voids formed between the irregular surfaces of the elongated, thin, plate-like pulverized material. Additionally, the previously tightly packed wood fibers separate, creating voids that allow water vapor to penetrate not only the surface but also the interior of the woody material. This is presumed to improve the efficiency of recovering cypress essential oil-containing distilled water during the distillation process.

[0041] Although the present invention has been described in detail above with reference to examples and test examples, the present invention can be practiced with a wide variety of modifications and changes within the scope of the invention as defined by the claims. [Explanation of symbols]

[0042] 1 Log 2 cutting blade 3 Single board 4 Peeled core

Claims

1. The essential oil extraction method comprises a preparation step of preparing the peeled core remaining after cutting a log to continuously obtain veneers, a crushing step of crushing the peeled core to obtain a crushed material, a distillation step of distilling the crushed material to obtain a distillate, and a separation step of separating the distillate into essential oil and aromatic distilled water.

2. 2. The essential oil extraction method according to claim 1, further comprising a water removal step for removing minute amounts of water contained in the essential oil obtained in the separation step.

3. 3. The essential oil extraction method according to claim 2, characterized in that the water removal step comprises cooling the essential oil obtained in the separation step to a temperature below the freezing point of water but above the freezing point of the essential oil components, and then filtering it to remove frozen water particles.

4. 2. The essential oil extraction method according to claim 1, wherein the pulverized material obtained by the pulverization step is a thin, elongated pulverized material having an average length of 10 to 30 mm, an average width of 3 to 10 mm, and an average thickness of 1 to 2 mm.

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