Drying apparatus and drying method

Abstract

[Problem] To provide a drying device and a drying method in which objects to be treated are conveyed by being slid over an open portion in a warm air atmosphere, and objects to be treated that are smaller than the open portion are passed through the open portion and classified while being continuously dried using a recovery section. [Solution] A drying device that dries objects to be treated using hot air, said device characterized by comprising a screw blade, an open portion that has an opening and that is disposed below the screw blade, and a recovery section positioned below the open portion, the rotation of the screw blade causing the objects to be treated to be conveyed by being slid over the open portion, and objects to be treated that are smaller than the opening being passed through the opening and classified by the recovery section.

Description

【Technical Field】 【0001】 The present invention relates to a drying apparatus and a drying method for heating and drying an object to be processed and performing classification. More specifically, the present invention relates to a drying apparatus and a drying method for heating and drying an object to be dried by using hot air or hot water obtained from a biomass boiler or a cogeneration apparatus for biomass, and performing classification, and particularly relates to a drying apparatus and a drying method for producing dried wood chips for biomass gasification power generation. 【Background Art】 【0002】 In recent years, for the purpose of preventing global warming and effectively utilizing regional resources, woody biomass such as thinned wood cut from forests is crushed and chipped, and this is thermally decomposed in a reducing atmosphere as a biomass fuel to be combustibly gasified, and a biomass gasification power generation apparatus that drives a gas engine with the combustible gas generated thereby to rotate and generate power has become widespread. 【0003】 This biomass gasification power generation apparatus can obtain a power generation efficiency of 20% to 30% even if it is small, and most of them have a power generation capacity of about 20 kW to 400 kW (per unit). In addition, the gasification power generation apparatus is a cogeneration system that uses a gas engine, and at the same time as power generation, hot water at about 80°C having a heat quantity about 1.5 to 2 times the power generation amount is generated from waste heat. 【0004】 By the way, raw wood and the like used as this woody biomass fuel have a moisture content of 50 to 60% and contain moisture. When a material with a high moisture content is used in a gasification power generation apparatus, the thermal decomposition temperature of the gasification furnace decreases and liquid tar of undecomposed components is generated. As a result, since it hinders the operation of the gasification power generation apparatus, it is stipulated by gasification manufacturers as in Non-Patent Document 1 to use biomass fuel chips dried to a moisture content of 10 to 15% or less. 【0005】 Even after several months of sun drying, it is difficult to dry biomass fuel chips to an equilibrium moisture content of approximately 20% or less, which is the level of humidity in the atmosphere. Therefore, drying with a drying device is necessary to achieve a moisture content of 10-15% or less, which is suitable for gasification power generation equipment. 【0006】 Businesses using biomass gasification power generation equipment typically purchase classified biomass fuel chips, install a drying unit in front of the gasification power generation equipment, and use hot air produced from hot water obtained from a cogeneration system to dry the chips to a moisture content of 10-15% or less. 【0007】 Furthermore, if the biomass fuel chips are too large, it becomes difficult to transport them within the gasifier of a gasification power generation system. On the other hand, if the chips are too small, they burn too quickly in the gasifier, resulting in an abnormal temperature rise within the gasifier. Therefore, the size of the chips is precisely specified by gasification power generation system manufacturers, as described in Non-Patent Document 1. 【0008】 Patent Document 1 discloses a rotary drying apparatus that can continuously dry an object to be dried by rotating it inside a rotating cylindrical body while drying it with hot air supplied from a hot air duct. 【0009】 Furthermore, Patent Document 2 discloses a configuration comprising a dryer for drying the finely ground biomass produced by the explosion machine, and a classifier 32 for classifying the biomass dried by the dryer. [Prior art documents] [Patent Documents] 【0010】 [Patent Document 1] Japanese Patent Publication No. 2012-251699 [Patent Document 2] Patent No. 6245436 [Non-patent literature] 【0011】 [Non-Patent Document 1] Volter40 brochure, Volter40 brochure [online], Volter Japan LLC, [Accessed February 13, 2023], Internet<URL:http: / / www.volter.jp / pdf / Volter40_pamphlet.pdf> [Overview of the Initiative] [Problems that the invention aims to solve] 【0012】 Thus, biomass fuel chips require drying using a drying device, but drying biomass fuel chips with a drying device generates a large amount of fine powder after drying. In particular, the rotary drying device disclosed in Patent Document 1 has the problem of generating a large amount of fine powder because the biomass fuel chips are pulverized as they rotate. 【0013】 Therefore, even though power generation companies purchased pre-classified biomass fuel chips, they still needed to use a sieving device after passing them through a drying device to remove fine particles. 【0014】 The present invention was devised in view of the above points, and its objective is to provide a drying apparatus and drying method that can heat-dry biomass fuel chips and simultaneously perform sieving and classification within the same apparatus. [Means for solving the problem] 【0015】 The drying apparatus according to the first invention is a drying apparatus for drying a workpiece with hot air, comprising a screw blade, an opening having an opening located below the screw blade, and a recovery unit located below the opening, wherein the screw blade rotates to transport the workpiece by sliding it over the opening, and the workpiece smaller than the opening is passed through the opening and sorted by the recovery unit. The opening includes a plurality of plate materials having an opening, and the size of the opening can be changed by shifting the planar arrangement of the plate materials. It is characterized by the following. 【0016】 TheThe drying device according to the second invention is a drying device for drying an object to be processed with warm air, comprising a screw blade, an opening portion disposed below the screw blade and having an opening, and a collection portion disposed below the opening portion. When the screw blade rotates, the object to be processed is slid on top of the opening portion for conveyance, and the object to be processed smaller than the opening is classified by the collection portion through the opening. The recovery section is provided with recovery screw blades that are parallel to the screw blades. It is characterized by the above. 【0017】 First Invention or second invention In the drying device according to the third invention, The screw blade is provided with at least one stirring blade section for stirring the material to be processed. It is characterized by the above. 【0018】 The drying device according to the fourth invention is based on the first invention or second invention In The screw blade is a shaftless screw blade that does not have a shaft member at the center of rotation. It is characterized by the above. 【0019】 The drying device according to the fifth invention is based on the first invention or second invention In An exhaust port is provided below the opening, and a dust collector is installed downstream of the exhaust port to remove dust. It is characterized by the above. 【0020】 The sixth invention The drying method is a drying method for drying a workpiece with hot air, comprising: a conveying step of conveying the workpiece by the rotation of a screw blade; a classifying step of classifying the workpiece in a recovery section using an opening that includes a plurality of plate materials having an opening and is located below the screw blade, the size of which can be changed by shifting the planar arrangement of the plate materials; and a recovery step of recovering the workpiece from the recovery section located below the opening, wherein the classifying step involves conveying the workpiece by sliding it over the opening, so that workpieces smaller than the opening pass through the opening and are classified by the recovery section. It is characterized by the above. 【0021】 The drying method according to the seventh invention is a drying method for drying an object to be processed with warm air, comprising a conveyance step of conveying the object to be processed by rotation of a screw blade, a classification step of classifying the object to be processed into a collection portion by an opening portion disposed below the screw blade and having an opening, and a collection step of collecting the object to be processed from the collection portion disposed below the opening portion. The classification step is characterized by classifying the object to be processed smaller than the opening by the collection portion through the opening by sliding the object to be processed on top of the opening portion for conveyance. A recovery screw blade is provided that is parallel to the aforementioned screw blade. It is characterized by the above. Furthermore, the drying apparatus according to the eighth invention is a drying apparatus for drying a workpiece with hot air, comprising a screw blade, an opening having an opening and positioned below the screw blade, and a recovery unit positioned below the opening, wherein the screw blade rotates to transport the workpiece by sliding it over the opening, and the workpiece smaller than the opening is passed through the opening and classified by the recovery unit, the opening includes a plurality of plate materials having openings, the size of the opening can be changed by shifting the planar arrangement of the plate materials, and the recovery unit is provided with a recovery screw blade parallel to the screw blade. 【Advantages of the Invention】 【0022】 The present invention, comprising the configuration described above, allows for the classification of materials smaller than the opening by sliding them over the opening in a hot air atmosphere using the rotation of screw blades, thereby allowing materials to be passed through the opening and continuously dried by the recovery section. [Brief explanation of the drawing] 【0023】 [Figure 1] Figure 1(a) is a front cross-sectional view showing an example of a drying apparatus according to the first embodiment, and Figure 1(b) is a left side cross-sectional view showing an example of a drying apparatus according to the first embodiment. [Figure 2] Figure 2(a) is a perspective view showing an example of a screw blade with a shaft member, Figure 2(b) is a perspective view showing an example of a screw blade without a shaft member, and Figure 2(c) is a perspective view showing an example of a screw blade with a stirring blade section. [Figure 3] Figure 3 is a perspective view showing an example of a wing and an opening. [Figure 4] Figure 4(a) is a plan view showing an opening made by circular hole punching, Figure 4(b) is a plan view showing an opening made by plain weave, and Figure 4(c) is a perspective view showing an opening made by wedge wire. [Figure 5] Figure 5(a) is a left side cross-sectional view showing an example of a drying apparatus according to the second embodiment, Figure 5(b) is a front cross-sectional view showing an example of a drying apparatus according to the second embodiment, and Figure 5(c) is a right side cross-sectional view showing an example of a drying apparatus according to the second embodiment. [Modes for carrying out the invention] 【0024】 The drying apparatus and drying method to which the present invention is applied will be described in detail below with reference to the drawings. 【0025】 Figure 1(a) is a front cross-sectional view showing an example of a drying apparatus 1 according to the first embodiment, and Figure 1(b) is a left side cross-sectional view showing an example of a drying apparatus 1 according to the first embodiment. 【0026】 The drying apparatus 1 comprises a drying chamber 21, a hot air generator 22 located above the drying chamber 21, and an exhaust port 23 located on the side of the drying chamber 21. 【0027】 Furthermore, the drying apparatus 1 includes a screw blade 31 arranged horizontally, an opening 41 located below the screw blade 31 and having an opening, and a recovery unit 5 located below the opening 41. A motor 32 is located at one end of the screw blade 31, and a bearing 33 is located at the other end. 【0028】 The recovery unit 5 comprises a recovery screw blade 61 and a recovery casing 71 positioned below the recovery screw blade 61. A recovery motor 62 is positioned at one end of the recovery screw blade 61, and a recovery bearing 63 is positioned at the other end. 【0029】 The exhaust port 23 is located below the opening 41. The exhaust port 23 is connected to the cyclone dust collector 27. The cyclone dust collector 27 is connected to the exhaust fan 28. 【0030】 An example of a screw blade 31 is shown in Figure 2(a). This screw blade 31 is formed by arranging helical blades 312 around a rotating shaft 311. Another example of a screw blade 31 is shown in Figure 2(b). This screw blade 31 is made up of helical blades 312, but it is a shaftless screw blade that does not have a shaft member in the space at the center of rotation. By making the screw blade 31 shaftless in this way, the region of the rotating shaft can be made hollow, so that hot air can pass through. This can improve the drying efficiency of the material to be processed. 【0031】 Figure 2(c) shows an example in which a stirring blade 313 is further provided in addition to the screw blade 31. The stirring blade 313 has at least one blade on the blade 312 that stirs the material to be processed. For example, the stirring blade 313 is a stainless steel metal rod and is joined to the blade 312 by metal welding. With this configuration, the rotation of the screw blade 31 can stir the material being conveyed and turn it upside down. As a result, the screw blade 31 can turn over the side of the material that contains a lot of moisture, thereby promoting drying. Here, the stirring blade 313 only needs to be shaped in a way that it can lift the material to be processed and turn it upside down, and any shape is acceptable as long as it has a hook part on the blade 312. 【0032】 In Figure 1(b), the screw blades 31 consist of three blades: screw blade 31a(31), screw blade 31b(31), and screw blade 31c(31). However, there may be four or six blades, or the drying apparatus may be made more compact by using only one screw blade 31. 【0033】 Figure 3 is a perspective view showing an example of a blade 312 and an opening 41. The motor 32 is connected to the blade 312. The opening 41 is located on the underside of the blade 312. The opening 41 is, for example, a screen made of circular holes punched with an opening. In Figure 3, the screen with an opening located on the underside of the blade 312 is also located on the side of the blade 312, but the opening 41 only needs to be on the underside of the blade 312, and the presence or absence of an opening on the side of the blade 312 is irrelevant. 【0034】 Figure 4 shows an example of an opening 41. Figure 4(a) is a perspective view showing a screen made by circular hole punching. Screens made by circular hole punching are made, for example, by punching out stainless steel sheet material. Figure 4(b) is a perspective view showing a screen made by plain weave. Screens made by plain weave are made, for example, by plain weaving metal wires vertically and horizontally. Figure 4(c) is a perspective view showing a screen made by wedge wire. Wedge wire is a screen that reduces clogging by forming slits by arranging wires with an inverted triangular cross-sectional shape at equal intervals. Due to the inverted triangular shape, the slits widen as the material to be processed passes through and falls between the slits, making it less likely to clog, thus providing excellent maintainability. Screens made by wedge wire are made, for example, by combining stainless steel wires. 【0035】 The opening 41 may be constructed by stacking multiple plates having openings, and the size of the opening can be changed by shifting the planar arrangement of the plates. This configuration makes it possible to change the size of the classification of the material to be processed. Furthermore, the opening 41 may be configured to change its size in the direction of the rotation axis of the screw blade 31. For example, the opening 41 may be configured to be smaller near the input port 24 and larger near the upper outlet 25. 【0036】 In the embodiment described above, the opening 41 is positioned below the screw blade 31, and the recovery unit 5 is positioned below the opening 41. However, by repeating the screw blade 31 and the opening 41 positioned below it as one set in two or more stages, multi-stage classification may be made possible. 【0037】 Figure 5(a) is a left side cross-sectional view showing an example of the drying apparatus 1 according to the second embodiment, Figure 5(b) is a front cross-sectional view showing an example of the drying apparatus 1 according to the second embodiment, and Figure 5(c) is a right side cross-sectional view showing an example of the drying apparatus 1 according to the second embodiment. Hereinafter, in the second embodiment, the same reference numerals are used for the same components and members as in the first embodiment described above, and their descriptions are omitted below. 【0038】 As shown in Figure 5(b), the drying apparatus 1 according to the second embodiment is connected to the feeder 8. 【0039】 The feeder 8 includes an opening / closing door 84 located on the top of the feeder 8, a raw material storage section 86, and a feeder screw blade 81 positioned horizontally. 【0040】 The supply screw blade 81 is connected to the screw blade 31 via a supply rotary valve 85. The screw blade 31 is connected to the upper outlet 25 via an upper outlet rotary valve 251. 【0041】 The recovery screw blade 61 is connected to the lower outlet 26 via the lower outlet rotary valve 261. 【0042】 Next, the operation of the drying apparatus 1 according to the first embodiment will be described. 【0043】 The material to be processed is fed in through the input port 24 and then transported by the screw blades 31. During this transport process, the material is exposed to hot air generated from the hot air generator 22, which promotes drying. 【0044】 The material to be processed is transported by sliding over the opening 41 due to the rotation of the screw blades 31. Only material smaller than the opening of the opening 41 falls into the opening and moves to the collection unit 5. 【0045】 The material to be processed, which has been transported without falling through the opening 41, is removed from the upper outlet 25. 【0046】 The material to be processed, having moved to the recovery section 5, is transported by the rotation of a recovery screw blade 61 positioned in the recovery section 5 parallel to the screw blade 31, and is removed from the lower outlet 26. In other words, the material to be processed can be classified. 【0047】 The material to be processed, which falls through the opening 41, is further dried by the hot air as it is transported by the recovery screw blades 61. 【0048】 By slowing down the rotation speed of the screw blades 31, the workpiece can be kept in the hot air of the drying chamber 21 for a longer period of time. This promotes drying. Furthermore, by lengthening the axial direction of the screw blades 31, the amount of workpiece dried while being conveyed by the screw blades 31 can be increased. 【0049】 Here, the rotational speeds of the screw blades 31 and the recovery screw blades 61 may be the same, but they may also be adjusted according to the amount of material to be processed after classification, and the rotational speeds of the screw blades 31 and the recovery screw blades 61 may be set to be different. 【0050】 Furthermore, by making the opening 41 smaller near the input port 24 and larger near the upper outlet 25, the material to be processed is less likely to fall through the opening immediately after being input, making it easier for it to be exposed to the hot air from the hot air generator 22, thereby promoting drying. 【0051】 Furthermore, in a configuration where the screw blades 31 and the opening 41 located below them are repeated in two or more stages as a set, it becomes possible to perform multi-stage classification by setting the size of the opening to be different in each stage. 【0052】 The hot air used for drying contains fine dust generated from wood chips, etc. Therefore, an exhaust port 23 for dust removal is provided below the opening 41, and a cyclone dust collector 27 and an exhaust fan 28 are placed downstream of the exhaust port to remove dust, thereby recovering the fine dust from the cyclone dust collector 27. The gas that does not contain fine dust after dust removal is released into the atmosphere by the exhaust fan 28. The fine dust recovered from the cyclone dust collector 27 can be reused as livestock bedding or as a bulking agent for plastic resins. 【0053】 Thus, in this invention, by rotating the screw blades 31 to slide and transport the workpiece over the opening 41 in a hot air atmosphere, workpieces smaller than the opening of the opening 41 are passed through the opening and collected in the collection unit 5, thereby enabling continuous drying and classification. 【0054】 Next, the operation of the drying apparatus 1 according to the second embodiment will be described. 【0055】 The material to be processed is introduced into the raw material storage section 86 through the opening / closing door 84. By closing the opening / closing door 84, the material to be processed is stored in an area that is isolated from the outside air. 【0056】 The supply screw blades 81 are driven and rotated by the supply motor 82. The material to be processed stored in the raw material storage section 86 is supplied to the supply screw blades 81 and conveyed by the rotational drive of the supply screw blades 81 based on the supply motor 82. 【0057】 The material to be processed, conveyed by the rotation of the supply screw blades 81, is supplied to the screw blades 31 of the drying apparatus 1 via the supply rotary valve 85. In this way, by using the supply rotary valve 85, the hot air in the drying chamber 21 does not return to the supply machine 8, and the temperature inside the drying chamber 21 can be stabilized. 【0058】 The material to be processed, which is transported without falling through the opening 41, is removed from the upper outlet 25 via the upper outlet rotary valve 251. 【0059】 The material to be processed, transported by the rotation of the recovery screw blades 61, is removed from the lower outlet 26 via the lower outlet rotary valve 261. 【0060】 In this way, by taking out the hot air through the upper outlet rotary valve 251 and the lower outlet rotary valve 261, the hot air inside the drying chamber 21 is not released into the outside air, and the temperature inside the drying chamber 21 can be stabilized. 【0061】 Thus, the drying apparatus 1 according to the second embodiment can classify the materials to be processed while continuously drying them stored in the raw material storage section 86. 【0062】 The drying method according to the present invention includes a conveying step in which the material to be processed is conveyed by the rotation of a screw blade 31. In this conveying step, the material to be processed is conveyed by sliding it over the opening 41, so that the material to be processed smaller than the opening passes through the opening and is classified by the recovery unit 5. The method then includes a classification step in which the material is classified by the opening 41 located below the screw blade 31 and is collected by the recovery unit 5 located below the opening 41. In this way, the drying method according to the present invention allows for the continuous drying and classification of the material to be processed. 【0063】 In the embodiments of the present invention, biomass fuel chips such as wood chips were presented as an example of the material to be processed, but the invention is not limited to biomass fuel chips and can also be applied to drying and classifying crushed plastics and the like. 【0064】 While embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. Such novel embodiments can be implemented in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as described in the claims. [Explanation of symbols] 【0065】 1 Drying device 21 Drying room 22 Hot air generator 23 Exhaust vent 24 Inlet 25 Upper outlet 251 Top outlet rotary valve 26 Trade-in Exit 261 Trade-in outlet rotary valve 27 Cyclone dust collector 28 Exhaust fan 31 Screw blades 311 Rotating shaft 312 feathers 313 Agitator blade 32 motors 33 Bearings 41 Opening 5. Recovery Section 61. Recovery screw blades 62 Recovery motor 63. Recovery bearing 71 Recovery casing 8 Feeding machine 81. Supply screw blades 82 Supply motor 83 Supply bearing 84 Opening and closing doors 85 Supply Rotary Valve 86 Raw Material Storage Department

Claims

[Claim 1] A drying apparatus that dries the workpiece using hot air, Screw blades and, An opening having an opening located below the screw blade, A recovery unit located below the opening Equipped with, As the screw blades rotate, the workpiece is transported by sliding it over the opening, and workpieces smaller than the opening are passed through the opening and classified by the recovery unit. The opening includes a plurality of plate materials having an opening, and the size of the opening can be changed by shifting the planar arrangement of the plate materials. A drying apparatus characterized by the following. [Claim 2] A drying apparatus that dries the workpiece using hot air, Screw blades and, An opening having an opening located below the screw blade, A recovery unit located below the opening Equipped with, As the screw blades rotate, the workpiece is transported by sliding it over the opening, and workpieces smaller than the opening are passed through the opening and classified by the recovery unit. The recovery section is provided with recovery screw blades oriented parallel to the screw blades. A drying apparatus characterized by the following. [Claim 3] The screw blades are provided with at least one stirring blade section for stirring the material to be processed. A drying apparatus according to claim 1 or 2, characterized by the following: [Claim 4] The screw blade is a shaftless screw blade that does not have a shaft member at the center of rotation. A drying apparatus according to claim 1 or 2, characterized by the following: [Claim 5] An exhaust port is provided below the aforementioned opening, A dust collector for dust removal was installed downstream of the aforementioned exhaust port. A drying apparatus according to claim 1 or 2, characterized by the following: [Claim 6] A drying method in which an object to be processed is dried with hot air, A conveying process in which the workpiece is conveyed by the rotation of screw blades, A classification process in which the material is classified in the recovery section by an opening which includes a plurality of plate materials having an opening and which is arranged below the screw blade, and whose size can be changed by shifting the planar arrangement of the plate materials, The process includes a recovery step of recovering from the recovery unit located below the opening, The classification process involves transporting the material to be processed by sliding it over the opening, thereby passing the material smaller than the opening through the opening and classifying it using the recovery unit. A drying method characterized by the following. [Claim 7] A drying method in which an object to be processed is dried with hot air, A conveying process in which the workpiece is conveyed by the rotation of screw blades, A classification step is performed in a recovery section equipped with a recovery screw blade positioned below the screw blade and having an opening, which is parallel to the screw blade. The process includes a recovery step of recovering from the recovery unit located below the opening, The classification process involves transporting the material to be processed by sliding it over the opening, thereby passing the material smaller than the opening through the opening and classifying it using the recovery unit. A drying method characterized by the following. [Claim 8] A drying apparatus that dries the workpiece using hot air, Screw blades and, An opening having an opening located below the screw blade, A recovery unit located below the opening Equipped with, As the screw blades rotate, the workpiece is transported by sliding it over the opening, and workpieces smaller than the opening are passed through the opening and classified by the recovery unit. The opening includes a plurality of plate materials having an opening, and the size of the opening can be changed by shifting the planar arrangement of the plate materials. The recovery section is provided with recovery screw blades oriented parallel to the screw blades. A drying apparatus characterized by the following.

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