Semi-carbonized pellet, preparation method thereof, and preparation system thereof

Abstract

To provide means for preparing semi-carbonized pellets of consistently uniform quality.SOLUTION: A preparation method for semi-carbonized pellets comprises a heating step of heating biomass powder in a reactor to obtain a semi-carbonized material, a washing step of washing the semi-carbonized material with a washing liquid, and a compression molding step of compression-molding the washed semi-carbonized material to obtain semi-carbonized pellets.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to torrefied pellets, a method for preparing same and a system for preparing same. [Background technology]

[0002] Coal is still widely used as fuel for thermal power generation. However, biomass-derived fuel pellets have recently been attracting attention as a potential alternative to coal. One such biomass-derived fuel pellet is a solid fuel made by semi-carbonizing biomass (hereinafter sometimes referred to as "black pellets").

[0003] One issue with black pellets is that scale generated during combustion of the black pellets can cause clogging and deterioration of boilers, etc. Therefore, Patent Document 1 proposes a technology for cleaning the biomass raw material during the production of black pellets, thereby reducing the content of substances that cause scale and / or corrosion during use in the boiler. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] WO2018 / 230715 Summary of the Invention [Problem to be solved by the invention]

[0005] The present inventors have examined the technology described in Patent Document 1 and found that even when performed under the same conditions, there is a problem in that performance varies between lots, making it impossible to consistently provide semi-carbide pellets of consistent quality. In light of this, an object of the present invention is to provide a means for consistently preparing semi-carbide pellets of consistent quality. [Means for solving the problem]

[0006] One aspect of the present invention is a heating step of heating biomass powder in a reactor to obtain semi-carbonized material; a washing step of washing the semi-carbide with a washing liquid; a pressure molding step of pressurizing the washed semi-carbide to obtain semi-carbide pellets; The present invention relates to a method for preparing semi-carbide pellets. Here, the cleaning step is a washing and draining step of washing the semi-carbonized material with a washing liquid and draining the liquid after washing; a quantification step of measuring the concentration of sodium and / or potassium in the effluent from the washing and draining step; The washing and draining step may be repeated until the concentration in the quantification step reaches a predetermined value. The predetermined value may be a specific value of 2000 ppm or less. Furthermore, the heating step includes a mass measurement step of measuring the mass of the contents in the reactor (biomass powder → semi-carbonized material) over time, which decreases as the heating process progresses; a heating stopping step of determining whether a target mass of the torrefied product has been reached based on the initial mass of the biomass powder in the reactor before the heating and the mass measured over time in the mass measuring step, and stopping the heating if the determination is affirmative; may have The initial mass of the biomass powder may be the mass of the biomass powder in a dry state. Furthermore, one aspect of the present invention is a reactor capable of storing biomass powder; A heating unit that heats the biomass powder in the reactor; a heating control unit that controls heating in the heating unit; a cleaning liquid inlet for introducing a cleaning liquid into the reactor; a cleaning liquid introduction control unit that controls introduction of the cleaning liquid at the cleaning liquid introduction unit; a cleaning liquid discharge section for discharging the cleaning liquid introduced into the reactor; Pressure molding section and It has The heating control unit controls the heating unit to perform heating control to heat the biomass powder in the reactor and obtain semi-carbonized material; the cleaning liquid introduction control unit controls the cleaning liquid introduction unit after the semi-carbide is obtained, and performs control to introduce a cleaning liquid into the reactor to clean the semi-carbide; The pressure molding unit is a semi-carbide pellet preparation system configured to pressurize the washed semi-carbide to prepare semi-carbide pellets. Also, a component measuring unit capable of quantifying sodium and / or potassium in the cleaning solution; a measurement control unit that controls the component measuring unit and measures the concentration of sodium and / or potassium in the discharged liquid from the cleaning liquid discharge unit; and The cleaning liquid introduction control unit may control the cleaning liquid introduction unit to introduce the cleaning liquid into the reactor until the concentration measured by the component measurement unit reaches a predetermined value. The predetermined value may be a specific value equal to or less than 2000 ppm (any value equal to or less than 2000 ppm). Further, a mass measuring unit capable of measuring the mass of the contents in the reactor is further provided, The heating control unit controls the mass measurement unit to measure, directly or indirectly, and over time, the mass of the contents in the reactor, which decreases as the reactor is heated, and may further determine whether the target mass of the semi-carbonized material has been reached based on the initial mass of the biomass powder in the reactor before the heating and the mass measured over time, and if the determination is positive, may control the heating unit to stop heating. The initial mass of the biomass powder may be the mass of the biomass powder in a dry state. Further, the apparatus further includes a recording unit that records information relating the initial mass of the biomass powder in the reactor before the heating and the target mass of the torrefied product; The heating control unit may determine a target mass of the torrefied product based on information recorded in the recording unit regarding the initial mass of the biomass powder in the reactor before the heating. Another aspect of the present invention is semi-carbide pellets obtained by the above-described preparation method. Furthermore, one embodiment of the present invention may be torrefied biomass powder itself. That is, torrefied material before being pelletized (pressure-molded). The torrefied biomass powder can be produced by a heating step in which biomass powder is heated in a reactor to obtain torrefied material, and a washing step in which the torrefied material is washed with a washing liquid (and, if necessary, a drying step). In the detailed description of torrefied pellets below, the description of the torrefied material up to the pressure-molding step will be referred to as the description of torrefied biomass powder (method for preparing torrefied biomass powder, system for preparing torrefied biomass powder). [Effects of the Invention]

[0007] The present invention can provide a means for always preparing semi-carbide pellets of consistent quality. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of an example of a system for preparing torrefied pellets according to the present embodiment. [Figure 2] FIG. 2 is a schematic diagram of an example of a kiln-type incinerator that can be used in this embodiment. [Figure 3] FIG. 3 is a functional block diagram showing a detailed example of a control unit that controls each unit of the preparation system. [Figure 4] FIG. 4 is a flowchart showing an example of control of the preparation system according to this embodiment. [Figure 5] FIG. 5 is a flowchart showing an example of control of the preparation system according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a semi-carbide pellet, a method for preparing the same, and a system for preparing the same according to one embodiment of the present invention will be described in order.

[0010] <Method for preparing semi-carbonized pellets> A method for preparing torrefied pellets according to one embodiment of the present invention includes a crushing step of crushing biomass (unreacted biomass), a drying step of drying the crushed unreacted biomass, a heating step of heating the dried biomass powder in a reactor to obtain torrefied material, a washing step of washing the torrefied material with a washing liquid, and a compression step of pressurizing the washed torrefied material (or, optionally, the torrefied material dried after the washing step) to obtain torrefied pellets. Each step is described in detail below.

[0011] (Crushing process) First, this preparation method includes a pulverization step for pulverizing biomass. Here, "biomass" refers to biomass in a state where no chemical reaction due to semi-carbonization has occurred. Furthermore, "semi-carbonized material" refers to biomass that has been subjected to a carbonization process and is partially carbonized but not completely, with room for further carbonization remaining (e.g., pyrolysis at 200-300°C in an inert atmosphere (ISO 16559)). The pulverization method is not particularly limited, and examples include methods using a blender, mortar, cutter mill, ball mill, etc. The size of the resulting pulverized material is also not particularly limited. From the perspective of improving the strength of the pellets, it is preferable to pulverize the biomass to a length of approximately 1 mm or less.

[0012] The biomass used in this preparation method is not particularly limited, but is preferably plant-derived biomass. Here, plant-derived biomass refers to organic resources derived from plants, including wood, dried vegetation, and agricultural or forestry waste. Specific examples include wood such as thinned wood, pruned branches, waste wood, and bark chips, bamboo, grass, coconut shells, rice husks, palm oil residue, discarded vegetables, vegetable waste, cut vegetables, fruit, sawdust, rice straw, wheat straw, and rice straw.

[0013] (drying process) This preparation method includes a drying step of drying the pulverized unreacted biomass. The drying method and conditions are not particularly limited, and can be such that most of the moisture in the unreacted biomass is removed (for example, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, or 95% by mass or more, based on the initial moisture content).

[0014] (Heating process) This preparation method includes a heating step in which the dried unreacted biomass powder is heated in a reactor to obtain a semi-carbonized product. The heating conditions are preferably an inert atmosphere (e.g., nitrogen, carbon dioxide, or other gas that does not react with the unreacted biomass powder) and a temperature range of 200 to 300°C, more preferably 250 to 300°C. The heating means may be a general heating furnace or superheated steam.

[0015] Here, the heating time in this heating step may be set in advance. On the other hand, it is preferable to be able to appropriately adjust the degree of carbonization of the unreacted biomass powder to meet the performance requirements (calorie content per unit mass) of the resulting torrefied pellets. Therefore, the heating step in the preparation method according to this embodiment preferably includes a mass measurement step in which the mass of the contents in the reactor, which decreases with heating, is measured directly or indirectly and over time, and a heating stop step in which, based on the initial mass of the unreacted biomass powder (unreacted biomass powder in a dry state) in the reactor before the heating and the mass measured over time in the mass measurement step, it is determined whether the target mass of the torrefied pellets has been reached, and if the determination is affirmative, the heating is stopped. In the mass measurement step, the mass of the contents (unreacted biomass powder to semi-carbonized material) in the reactor is measured over time. Either a method of directly measuring the mass of the contents or a method of measuring the mass of the entire reactor (reactor + contents) and then subtracting the mass of the reactor to indirectly derive the mass of the contents may be used. In this way, by focusing on the decrease in mass of the contents due to heating, semi-carbonized material with the desired carbonization degree can be obtained.

[0016] (Cleaning process) This preparation method includes a washing step in which the torrefied material is washed with a washing liquid. Hereinafter, the washing step will be described using an example in which the washing liquid is water, i.e., a water-washing step in which the torrefied material is washed with water. In other words, hereinafter, the "water" used as the washing liquid may be referred to as the "washing liquid," and the "water-washing step" may be referred to as the "washing step." Here, the water-washing step is a step in which water is continuously or intermittently introduced into a reactor to wash the torrefied material inside the reactor. To efficiently wash the torrefied material, the reactor may have an agitator that stirs the introduced water and the torrefied material. In this way, washing is performed in a state in which the cell walls are broken (torrefied), making it possible to wash the entire cell, compared to conventional washing before torrefaction (in which mainly only the cell surface is washed). As a result, lot-to-lot variation can be minimized.

[0017] The purpose of this washing is to remove specific components present in the semi-carbide (e.g., metals (e.g., sodium and potassium) that cause furnace corrosion and filter clogging, and chlorine that causes dioxins, etc.). However, measuring the concentration of specific components in the semi-carbide by removing the semi-carbide from the reactor during washing reduces production efficiency. Therefore, this washing process preferably includes a quantification step in which the wastewater after washing the semi-carbide with water is sampled and the specific components in the wastewater are quantified. By continuing washing until the concentration of the specific components in the quantification step reaches a predetermined value, the amount of the specific components in the semi-carbide can be reduced to a desired value or less. Preferably, washing is continued until the concentration of sodium and / or potassium (concentration in the wastewater) of the specific components reaches a desired value of 2000 ppm or less. The inventors have discovered that continuing washing until the wastewater reaches a concentration below this level improves the performance of the semi-carbide pellets obtained thereafter. In this preparation method, the water-containing semi-carbide is dried, and then the next pressure molding step is carried out.

[0018] (Pressure molding process) This preparation method includes a pressure molding step in which the semi-carbide material that has been washed and dried is pressure molded to obtain semi-carbide pellets. Here, the pressure molding is preferably hot pressure molding. The semi-carbide material that has been washed and dried may be molded as is, or, if necessary, the semi-carbide material obtained may be further pulverized by crushing or the like before molding. The size and shape of the pellets are not particularly limited. The hot pressure molding is preferably performed at a temperature ranging from greater than 100°C to 200°C, more preferably from 120°C to 180°C. The temperature of the hot pressure molding refers to the temperature of the mold used for molding. Pressure molding can be performed, for example, by extrusion molding using a ring die or flat die pelletizer, or by briquetting using a roll molding machine.

[0019] <Preparation System> The semi-carbide pellet preparation system according to this embodiment will be described in detail below with reference to Fig. 1. As shown in Fig. 1, the preparation system 100 according to this embodiment includes a crushing unit 101 that crushes biomass to prepare raw biomass powder, a drying unit 102 that dries the crushed raw biomass powder, a reactor 103 that can store biomass powder, a heating unit 104 that heats the biomass powder introduced into the reactor 103, a cleaning liquid introduction unit 105 that introduces a cleaning liquid into the reactor 103, a cleaning liquid discharge unit 106 that discharges the cleaning liquid introduced into the reactor 103, a compression unit 107 configured to compress the resulting semi-carbide into pellets, a component measurement unit 108 (e.g., a flame photometer and an ion electrode) that measures the concentration of components (sodium, potassium, etc.) in the discharged liquid, a mass measurement unit 109 that measures the mass of the reaction unit 103 (or the mass of the contents in the reaction unit 103), and a control unit 110 that controls each unit of the preparation system 100. The device used in this system is preferably a kiln-type incinerator (i.e., as shown in Figure 2, a is the biomass powder inlet, b is the cleaning liquid introduction section 105, c is the reaction section 103, d is the semi-carbonized material outlet, e is the cleaning liquid discharge section (wastewater in this example) 106, f is the heated air inlet, g is the heated air outlet, and h is the pyrolysis gas outlet).

[0020] 3 is a functional block diagram showing details of the control unit 110 that controls each unit of the preparation system 100. As shown in FIG. 3, the control unit 110 includes a pulverization control unit 110a that controls pulverization in the pulverization unit 101, a drying control unit 110b that controls drying in the drying unit 102, a heating control unit 110c that controls heating in the heating unit 104, a cleaning liquid introduction control unit (shown as a water introduction control unit in the figure as an example) 110d that controls the introduction of cleaning liquid in the cleaning liquid introduction unit 105, a compression control unit 110e that controls compression in the compression unit 107, a concentration measurement control unit 110f that measures the concentration of a predetermined component in the component measurement unit 108, a mass measurement control unit 110g that controls mass measurement in the mass measurement unit 109, and an information recording unit 110h that records various information necessary for control.

[0021] The information storage unit 110h includes a grinding condition storage unit 110h-1 in which grinding condition information, which associates the type and / or amount of biomass with the grinding conditions, is stored; a drying condition storage unit 110h-2 in which drying condition information, which associates the type and / or amount of biomass with the drying conditions (drying time, drying temperature), is stored; and a target mass reduction information storage unit 110h-3 in which the type and / or amount of biomass, the required calorific value (the required calorific value per unit mass of the resulting semi-carbonized pellets), and the target mass reduction (the difference between the mass of uncarbonized biomass at the time of input and the target mass of semi-carbonized material). While the present embodiment is configured to store the target mass reduction, it is sufficient if information regarding the amount of weight reduction of the contents by heating is stored; for example, information regarding the target mass of the reactor (mass of the reactor = mass of the reactor + mass of the contents) may be stored.

[0022] Table 1 shows an example of information stored in the target mass reduction information storage unit 110h-3. In the example below, the type of biomass, the initial mass introduced into the reactor, the required calorific value when converted into black pellets, and the target mass reduction that indicates when heating should be completed are all linked and recorded. For example, according to the example below, even if the type and initial mass of biomass are the same, the target (reduction) mass is configured to change depending on the required calorific value. (In the example below, if the biomass type is A and the initial input amount is X1, when the required calorific value is Y1, the target (reduction) mass is Z1, and when the required calorific value is Y2, the target (reduction) mass is Z3.) Furthermore, even if the mass and required calorific value of the biomass are the same, the target (reduction) mass is configured to change depending on the type of biomass. (In the example below, if the initial mass is X1 and the required calorific value is Y1, the target (reduction) mass is Z1 when the biomass type is A, and the target (reduction) mass is Z4 when the biomass type is B.)

[0023] TIFF2025024612000001.tif98170

[0024] Next, the control of the preparation system according to this embodiment will be described with reference to FIGS. 4 and 5. First, in step 101, the grinding control unit 110a determines grinding conditions (e.g., grinding time) based on the type and / or amount of biomass by referring to the grinding condition storage unit 110h-1. Next, in step 103, the grinding control unit 110a operates the grinding unit 101 according to the grinding conditions to start grinding the biomass. Next, in step 105, the grinding control unit 110a determines whether the determined grinding conditions (e.g., grinding time) have been completed. If the answer is Yes in step 105, the process proceeds to the next step. If the answer is No in step 105, the grinding process continues. Next, if the answer is Yes in step 105, i.e., after the scheduled grinding process is completed, in step 107, the drying control unit 110b determines drying conditions (e.g., drying time, drying temperature) by referring to the drying condition storage unit 110h-2 based on the type, state, and / or amount of biomass. Next, in step 109, the drying control unit 110b operates the drying unit 102 according to the drying conditions to start drying the pulverized biomass. Next, in step 111, the drying control unit 110b determines whether the determined drying conditions (e.g., pulverization time) have been completed. If the answer is Yes in step 111, the process proceeds to the next step; if the answer is No in step 111, the drying process continues. Next, if the answer is Yes in step 111, that is, after the scheduled drying process has been completed, in step 113, the heating control unit 110c determines the heating conditions (e.g., heating temperature) and target mass (or target weight loss) based on the desired calorific value of the resulting torrefied product, by referring to the heating condition memory unit 110h-3. Here, "target mass" means the target mass of the reaction section 103 (or the mass of the contents in the reaction section 103) after heating, taking into account the mass of the reaction section 103 (or the mass of the contents in the reaction section 103) before heating, and "target weight loss" means the difference between the mass of the reaction section 103 (or the mass of the contents in the reaction section 103) before heating and the target mass of the reaction section 103 (or the mass of the contents in the reaction section 103) after heating. Next, in step 115, the heating control section 110c operates the heating section 103 according to the heating conditions to start heating the biomass powder.Next, in step 117, the mass measurement control unit 110h controls the mass measurement unit 109 to measure the mass of the reaction unit 103 (or the contents in the reaction unit 103). Next, in step 119, the heating control unit 110c determines whether the mass measured in step 117 has reached the target mass (or the target weight loss), i.e., whether the scheduled heating has been completed. If the answer is Yes in step 119, the heating control unit 110c stops heating by the heating unit in step 121 because the scheduled heating process has been completed. If the answer is No in step 119, the process returns to step 117. Next, in step 123, the cleaning liquid introduction control unit 110d controls the cleaning liquid introduction unit 105 to introduce a cleaning liquid (water in the figure as an example) into the reaction unit 103 in order to wash the semi-carbonized material in the reaction unit 103. Here, the cleaning liquid may be introduced continuously or intermittently. Next, in step 125, the component measurement control unit 110g controls the component measurement unit 108 to quantify the amount of a predetermined component (sodium, potassium, etc.) in the wastewater from the reactor. Next, in step 127, the cleaning liquid introduction control unit 110d determines whether the amount of the component measured in step 125 has reached a predetermined amount. If the answer is Yes in step 127, in step 129, the cleaning liquid introduction control unit 110d controls the cleaning liquid introduction unit 105 to stop the introduction of the cleaning liquid (water in the figure as an example) into the reaction unit 103. On the other hand, if the answer is No in step 127, the process proceeds to step 125, where the quantitative analysis of the predetermined component continues. If the answer is Yes in step 127, that is, after the washing of the torrefied material is completed (via a drying process if necessary), in step 131, the compression control unit 110f controls the compression unit 107 to pelletize the torrefied material obtained in step 127 after washing, and stops the operation of the compression unit 107 after all the torrefied material has been pelletized.

[0025] In this embodiment, the mass of the entire reaction section is measured, and heating is terminated when the change in mass of the entire reaction section before and after the reaction reaches a predetermined value, but this is not limited to this. For example, the contents of the reactor may be removed (sampled), and heating may be terminated when the change in mass between the initial mass and the mass at the time of removal reaches a predetermined value.

[0026] <Semi-carbide pellets> The torrefied pellets (also called black pellets) obtained by the method of this embodiment can be used as fuel in various situations, and can achieve a desired calorific value per unit mass when burned. [Explanation of symbols]

[0027] 100 Preparation System 101 Crushing section 102 Drying section 103 Reactor 104 Heating section 105 Cleaning liquid introduction part 106 Cleaning fluid discharge section 107 Compression section 108 Component measurement section 109 Mass measurement section 110 control section 110a Grinding control section 110b Drying control unit 110c Heating control unit 110d Cleaning liquid introduction control unit 110e Compression control section 110f Concentration measurement control section 110g Mass measurement control section 110h Information recording section 110h-1 Grinding condition memory section 110h-2 Drying condition recording section 110h-3 Target mass reduction information recording section

Claims

1. A heating step of heating the biomass powder in a reactor to obtain semi-carbonized material; a washing step of washing the semi-carbide with a washing liquid; a pressure molding step of pressurizing the washed semi-carbide to obtain semi-carbide pellets; The method for preparing semi-carbide pellets comprising the steps of:

2. The washing step comprises: A washing and draining step of washing the semi-carbonized material with a washing liquid and draining the washing liquid after washing; A quantitative step of measuring the concentration of sodium and / or potassium in the drainage liquid in the washing and drainage step; The preparation method according to claim 1 , wherein the washing and draining step is carried out until the concentration in the quantification step reaches a predetermined value.

3. The method according to claim 2, wherein the predetermined value is a specific value that is 2000 ppm or less.

4. The heating step includes a mass measuring step of directly or indirectly measuring the mass of the content in the reactor over time, the mass decreasing with heating; a heating stop step of determining whether or not a target mass of the semi-carbonized material has been reached based on an initial mass of the biomass powder in the reactor before the heating and the mass measured over time in the mass measurement step, and stopping the heating if the determination is affirmative; 2. The method of claim 1, comprising:

5. The method of claim 4 , wherein the initial mass of the biomass flour is the mass of the biomass flour in a dry state.

6. A reactor for containing the biomass flour; A heating unit that heats the biomass powder in the reactor; A heating control unit that controls heating in the heating unit; A cleaning liquid inlet for introducing a cleaning liquid into the reactor; a cleaning liquid introduction control unit for controlling introduction of the cleaning liquid through the cleaning liquid introduction unit; A cleaning liquid discharge section for discharging the cleaning liquid introduced into the reactor; Pressurized molding section and It has The heating control unit controls the heating unit to perform heating control for heating the biomass powder in the reactor to obtain semi-carbonized material; the cleaning liquid introduction control unit controls the cleaning liquid introduction unit after the semi-carbide is obtained, and controls the introduction of a cleaning liquid into the reactor to clean the semi-carbide; The pressure molding unit is configured to pressure mold the washed semi-carbide to prepare semi-carbide pellets.

7. A component measuring unit capable of quantifying sodium and / or potassium; a measurement control unit that controls the component measuring unit and measures the concentration of sodium and / or potassium in the drainage liquid from the cleaning liquid drain unit; and The system according to claim 6, wherein the cleaning liquid introduction control unit controls the cleaning liquid introduction unit to introduce a cleaning liquid into the reactor to continue cleaning the carbonized material until the concentration measured by the component measuring unit reaches a predetermined value.

8. 8. The system of claim 7, wherein the predetermined value is a specified value that is less than or equal to 2000 ppm.

9. Further comprising a mass measuring unit capable of measuring the mass of the contents in the reactor, The system described in claim 6, wherein the heating control unit controls the mass measuring unit to directly or indirectly measure the mass of the contents in the reactor, which decreases as the contents are heated, over time, and further determines whether or not the target mass of the semi-carbonized material has been reached based on the initial mass of the biomass powder in the reactor before the heating and the mass measured over time, and if the determination is positive, controls the heating unit to stop heating.

10. The system of claim 9 , wherein the initial mass of the biomass flour is a mass of the biomass flour in a dry state.

11. The apparatus further includes a recording unit that records information relating to an initial mass of the biomass powder in the reactor before the heating and a target mass of the semi-carbonized material; The system of claim 9 , wherein the heating control unit determines a target mass of the torrefied material based on information recorded in the record unit about an initial mass of the biomass powder in the reactor before the heating.

12. Semicarbide pellets obtained by the preparation method according to any one of claims 1 to 5.

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