Biomass solid fuel production system

Abstract

This disclosure describes a biomass solid fuel production system that uses the heat from exhaust gas discharged from a combustion furnace to heat a heat transfer medium in a heat exchanger, and that can heat the heat transfer medium to a predetermined target temperature even if the heat exchanger deteriorates over time. [Solution] The biomass solid fuel production system comprises a heating device that heats biomass raw materials to produce biomass solid fuel, a combustion furnace that burns the pyrolysis gas generated by heating the biomass raw materials in the heating device to produce combustion gas, a heat exchanger that exchanges heat between the combustion gas produced in the combustion furnace and a heat transfer medium to heat the heat transfer medium, a measuring unit that measures the temperature of the heat transfer medium after it has been heated in the heat exchanger, a control unit that adjusts the temperature of the combustion gas supplied to the heat exchanger, and a control unit. The control unit performs a process to control the control unit so that the temperature measured by the measuring unit becomes a predetermined target temperature.

Description

Technical Field

[0001] The present disclosure relates to a manufacturing system for biomass solid fuel.

Background Art

[0002] Patent Document 1 discloses a manufacturing apparatus for biomass solid fuel (PBT (registered trademark): Pelletizing Before Torrefaction). The apparatus of Patent Document 1 includes an externally heated rotary kiln and a combustion furnace. The rotary kiln is configured to heat (low-temperature carbonize) a pellet-shaped biomass molded body (WP: White Pellet) input as a raw material to produce biomass solid fuel.

[0003] The rotary kiln includes a cylindrical main body into which the biomass molded body before heating is input from one end side and from which the biomass solid fuel after heating is discharged from the other end side, and a heating unit arranged to cover the outer peripheral portion of the cylindrical main body and configured to heat the biomass molded body flowing inside the cylindrical main body. The inside of the cylindrical main body is maintained in a low-oxygen atmosphere (reducing atmosphere) by supplying an inert gas. The pyrolysis gas (biogas) generated by heating the biomass molded body inside the cylindrical main body is supplied to the combustion furnace.

[0004] The combustion furnace is configured to burn the pyrolysis gas supplied from the rotary kiln to generate combustion gas and supply the combustion gas to the heating unit. That is, the pyrolysis gas generated by heating the biomass molded body in the rotary kiln is used as fuel for the combustion furnace, and the heat of the combustion gas generated by burning the pyrolysis gas in the combustion furnace is used for heating the biomass molded body in the rotary kiln, enabling the production of a self-sustaining type of biomass solid fuel.

[0005] Patent Document 2 discloses a power generation system that effectively utilizes the thermal energy of factory waste heat by introducing factory waste heat (heat of exhaust gas from a factory) into a heat exchanger to heat a part of the condensate.

Prior Art Documents

[0006] [Patent Document 1] International Publication No. 2022 / 209196 [Patent Document 2] Japanese Patent Publication No. 2014-105642 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Incidentally, exhaust gas from factories can contain various impurities such as dust. When such impurities are introduced into a heat exchanger along with the exhaust gas, they can adhere to and accumulate on the heat transfer surface (gas-side heat transfer surface) of the heat exchanger that does not come into contact with the heat transfer medium. Therefore, in the power generation system described in Patent Document 2, as the operating time increases, the amount of impurities accumulated on the gas-side heat transfer surface may increase, potentially leading to a decrease in heat exchange efficiency over time.

[0008] Therefore, this disclosure describes a biomass solid fuel production system that uses the heat from exhaust gas discharged from a combustion furnace to heat a heat transfer medium in a heat exchanger, and that can heat the heat transfer medium to a predetermined target temperature even if the heat exchanger deteriorates over time. [Means for solving the problem]

[0009] An example of a biomass solid fuel production system includes a heating device configured to produce biomass solid fuel by heating biomass raw materials, a combustion furnace configured to produce combustion gas by burning the pyrolysis gas generated by heating the biomass raw materials in the heating device, a heat exchanger configured to heat the heat transfer medium by exchanging heat between the combustion gas produced in the combustion furnace and the heat transfer medium, a measuring unit configured to measure the temperature of the heat transfer medium after it has been heated in the heat exchanger, a adjusting unit configured to adjust the temperature of the combustion gas supplied to the heat exchanger, and a control unit. The control unit is configured to perform a process to control the adjusting unit so that the temperature measured by the measuring unit becomes a predetermined target temperature. [Effects of the Invention]

[0010] According to the biomass solid fuel manufacturing system described herein, when using the heat from exhaust gas discharged from a combustion furnace to heat the heat transfer medium in a heat exchanger, it is possible to heat the heat transfer medium to a predetermined target temperature even if the heat exchanger deteriorates over time. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic diagram illustrating an example of a biomass solid fuel production system. [Figure 2] Figure 2 is a block diagram showing an example of the main components of the manufacturing system shown in Figure 1. [Figure 3] Figure 3 is a schematic diagram showing an example of the controller's hardware configuration. [Figure 4] Figure 4 is a schematic diagram illustrating another example of a biomass solid fuel production system. [Figure 5] Figure 5 is a schematic diagram illustrating another example of a biomass solid fuel production system. [Modes for carrying out the invention]

[0012] In the following descriptions, the same reference numeral will be used for identical elements or elements with the same function, and redundant explanations will be omitted. Furthermore, in this specification, when referring to the top, bottom, right, and left of a figure, the direction of the reference numeral in the figure will be used as the reference.

[0013] [Biomass Solid Fuel Production System] First, with reference to Figure 1, the configuration of the biomass solid fuel production system 1 will be described. The production system 1 is configured to produce biomass solid fuel BF from biomass raw material BM, and to recover heat by burning the pyrolysis gas PG generated during the production process of biomass solid fuel BF. That is, as illustrated in Figure 1, the production system 1 comprises a fuel production facility 100 for producing biomass solid fuel BF, a heat recovery facility 200 for recovering heat, and a controller Ctr (control unit).

[0014] The biomass raw material BM used in manufacturing system 1 is not particularly limited. For example, the biomass raw material BM may be woody biomass or herbaceous biomass. Woody biomass may be obtained by crushing at least one of wood chips and waste wood. Woody biomass may be, for example, construction waste wood, forest residue, sawmill residue, palm kernel shells, rice husks, rice straw, wheat straw, animal feed, waste paper, etc., or crushed materials thereof. The biomass raw material BM used in manufacturing system 1 may be a biomass molded body that has been pressure-molded into a predetermined shape (e.g., pellet or briquette) by a molding machine (e.g., pelletizer or briquette machine).

[0015] The degree of carbonization of the biomass solid fuel BF produced in manufacturing system 1 is not particularly limited. That is, the degree of carbonization of the biomass solid fuel BF may be high or low.

[0016] [Fuel production equipment] As illustrated in Figure 1, the fuel production facility 100 includes a heating device 110 and a combustion furnace 120.

[0017] The heating device 110 is configured to carbonize the biomass raw material BM by heating the biomass raw material BM with the combustion gas CG supplied from the combustion furnace 120, thereby generating the biomass solid fuel BF. The heating device 110 includes a cylindrical main body 111, a girth gear 112, a plurality of tires 113, a plurality of support portions 114, a discharge portion 115, and a heating portion 116. The heating device 110 may be, for example, an externally heated rotary kiln.

[0018] The cylindrical main body 111 is an elongated object having a substantially cylindrical shape. The cylindrical main body 111 includes one end portion 111a (inlet portion) into which the biomass raw material BM is introduced and the other end portion 111b (outlet portion) from which the biomass solid fuel BF is discharged. That is, the biomass raw material BM flows through the inside of the cylindrical main body 111 from the one end portion 111a toward the other end portion 111b. The cylindrical main body 111 may be installed such that its longitudinal direction extends along the horizontal direction, or may be installed such that its longitudinal direction is inclined with respect to the horizontal direction. In the latter case, the cylindrical main body 111 may be installed so as to incline downward from the one end portion 111a toward the other end portion 111b.

[0019] The girth gear 112 is fixed to the outer peripheral surface of the cylindrical main body 111 so as to extend along the circumferential direction of the cylindrical main body 111. That is, the girth gear 112 has a substantially annular shape. The girth gear 112 has a gear shape in which concavities and convexities are arranged alternately in its circumferential direction. The girth gear 112 meshes with a pinion gear (not shown), and is rotated by a drive source (for example, an electric motor) (not shown) rotating the pinion gear. Thereby, the rotational force of the pinion gear is transmitted to the cylindrical main body 111 via the girth gear 112. As a result, the cylindrical main body 111 rotates around a rotation axis extending along its longitudinal direction.

[0020] The installation position of the girth gear 112 with respect to the cylindrical body 111 is not particularly limited. As illustrated in FIG. 1, the girth gear 112 may be located closer to one end portion 111a of the cylindrical body 111 in the longitudinal direction of the cylindrical body 111. A plurality of girth gears 112 may be provided on the outer peripheral surface of the cylindrical body 111.

[0021] Each of the plurality of tires 113 is fixed to the outer peripheral surface of the cylindrical body 111 so as to extend along the circumferential direction of the cylindrical body 111. That is, each of the plurality of tires 113 has a substantially annular shape. Each tire 113 is supported by a support portion 114 (for example, a support roller). That is, the outer peripheral surface of the tire 113 is in direct contact with the outer peripheral surface of the support portion 114. Therefore, the outer peripheral surface of the tire 113 and the outer peripheral surface of the support portion 114 may be smoothed for reducing frictional resistance.

[0022] The plurality of tires 113 may be arranged at a predetermined interval in the longitudinal direction of the cylindrical body 111. As illustrated in FIG. 1, the heating device 110 may include two tires 113. In this case, one tire 113 may be located closer to one end portion 111a of the cylindrical body 111, and the other tire 113 may be located closer to the other end portion 111b of the cylindrical body 111.

[0023] The discharge portion 115 is connected to the other end portion 111b of the cylindrical body 111 and forms a discharge space connected to the internal space of the cylindrical body 111. The discharge portion 115 receives the biomass solid fuel BF discharged from the other end portion 111b of the cylindrical body 111 and discharges the biomass solid fuel BF from a discharge port provided at the lower end portion. All of the biomass solid fuel BF discharged from the discharge port of the discharge portion 115 may be shipped out as products to the outside. The discharge portion 115 receives the pyrolysis gas PG generated by heating the biomass raw material BM in the cylindrical body 111 and discharges the pyrolysis gas PG toward the combustion furnace 120 through the pipe D1 from an exhaust port provided at the upper end portion.

[0024] The heating element 116 is positioned to cover the outer circumference of the cylindrical body 111, and the overall shape is cylindrical. The heating element 116 may be positioned in the central part of the cylindrical body 111 in its extending direction. As illustrated in Figure 1, the heating element 116 may extend along the extending direction of the cylindrical body 111 between the two tires 113.

[0025] The heating unit 116 is connected to the combustion furnace 120 by piping D2 (second flow path). Therefore, high-temperature combustion gas CG (high-temperature combustion gas CGa) discharged from the combustion furnace 120 is introduced into the heating unit 116 through piping D2. In other words, the heating unit 116 is configured to indirectly heat the biomass raw material BM flowing inside the cylindrical body 111 by heating the outer wall (outer surface) of the cylindrical body 111 with the high-temperature combustion gas CGa. The temperature of the high-temperature combustion gas CGa may be, for example, around 1000°C.

[0026] The heating unit 116 may, for example, heat the biomass raw material BM to approximately 240°C to 700°C in a low-oxygen atmosphere (for example, with an oxygen concentration of 10% or less inside the cylindrical body 111). When the biomass raw material BM inside the cylindrical body 111 is heated by the heating unit 116, pyrolysis gas PG is generated from the biomass raw material BM, and the biomass raw material BM is carbonized to become a char. Pyrolysis gas PG is a mixed gas of gaseous organic components and water vapor.

[0027] The high-temperature combustion gas CGa introduced into the heating section 116 heats the outer wall (outer surface) of the cylindrical body 111, causing the temperature of the high-temperature combustion gas CGa to decrease and become low-temperature combustion gas CG (low-temperature combustion gas CGb). The temperature of the low-temperature combustion gas CGb may be, for example, around 200°C to 500°C. The low-temperature combustion gas CGb may be exhausted to the outside of the system (e.g., the atmosphere) through piping D3 connected to the heating section 116 by a blower F. The blower F is controlled based on a control signal from the controller Ctr. This controls the operation (driving or stopping) of the blower F and adjusts the airflow rate of the blower F. The blower F may be, for example, an induced draft fan. A dust collector (e.g., a cyclone) configured to collect dust contained in the low-temperature combustion gas CGb may be provided between the blower F and the heating section 116 in piping D3.

[0028] A valve V1 is provided on the upstream side of the blower F in the piping D3. The valve V1 is controlled based on a control signal from the controller Ctr and is configured to adjust the opening degree by opening and closing the piping D3 before and after the valve V1.

[0029] As illustrated in Figure 1, the downstream end of pipe D2 may be connected to the other end 111b of the cylindrical body 111 within the heating section 116. The upstream end of pipe D3 may be connected to the one end 111a of the cylindrical body 111 within the heating section 116. In this case, the high-temperature combustion gas CGa introduced into the heating section 116 from pipe D2 heats the outer wall (outer surface) of the cylindrical body 111, flows towards the one end 111a of the cylindrical body 111 within the heating section 116, and becomes low-temperature combustion gas CGb. Subsequently, the low-temperature combustion gas CGb is discharged from the heating section 116 to the outside of the system through pipe D3. Thus, the heating device 110 illustrated in Figure 1 is a counter-flow type in which the flow direction of the biomass raw material BM flowing inside the cylindrical body 111 and the flow direction of the high-temperature combustion gas CGa flowing inside the heating section 116 are opposite. The heating device 110 may also be a parallel flow type in which these flow directions are the same.

[0030] From the middle of pipe D3 (upstream of valve V1), pipe D4 branches off and extends. The downstream end of pipe D4 is connected to the heat exchanger 270 (described later) of the heat recovery equipment 200. Therefore, the low-temperature combustion gas CGb discharged from the heating section 116 can be supplied to the heat exchanger 270 through pipes D3 and D4. In other words, a portion of pipe D3 (the part of pipe D3 from the upstream end to the branching point) and pipe D4 constitute a flow path (first flow path) for introducing the low-temperature combustion gas CGb into the heat exchanger 270.

[0031] The piping D4 is equipped with a valve V2 and a sensor SE1, in order from the upstream side. Valve V2 is controlled based on a control signal from the controller Ctr and is configured to adjust the opening by opening and closing the piping D4 before and after valve V2. Sensor SE1 is a thermometer configured to measure the temperature of the combustion gas CG (more specifically, a mixed gas MG1 of low-temperature combustion gas CGb and high-temperature combustion gas CGa, which will be supplied to the heat exchanger 270). Sensor SE1 is configured to transmit the measured temperature data to the controller Ctr. Note that piping D4 does not necessarily have to be branched from piping D3. That is, the upstream end of piping D4 may be connected to the heating section 116. The mixed gas MG1 contains at least low-temperature combustion gas CGb.

[0032] The combustion furnace 120 is configured to produce combustion gas CG by burning the pyrolysis gas PG generated by heating the biomass raw material BM in the heating device 110. In the combustion furnace 120, at least one of the pyrolysis gas PG supplied through piping D1 and fuel supplied from an external source (e.g., liquefied petroleum gas (LPG)) is mixed with air supplied from an external source and burned at a high temperature. The pyrolysis gas PG is completely combusted. The high-temperature combustion gas CGa produced by the combustion is supplied to the heating section 116 through piping D2.

[0033] From the middle of pipe D2, pipe D5 branches off and extends. The downstream end of pipe D5 is connected to the section of pipe D4 between valve V2 and sensor SE1. Therefore, the high-temperature combustion gas CGa discharged from the combustion furnace 120 can be supplied to the heat exchanger 270 through pipes D2 and D5. In other words, a portion of pipe D2 (the part of pipe D2 from the upstream end to the branching point) and pipe D5 constitute a flow path (third flow path) for introducing the high-temperature combustion gas CGa into the heat exchanger 270.

[0034] In piping D5, valves V3 (adjustment unit, flow control valve) are provided in order from the upstream side. Valve V3 is controlled based on a control signal from controller Ctr and is configured to open and close piping D5 before and after valve V3 to adjust the opening degree. By controlling the opening degree of valve V3 by controller Ctr, the flow rate of high-temperature combustion gas CGa flowing through piping D5 is adjusted. In other words, the amount of high-temperature combustion gas CGa mixed with low-temperature combustion gas CGb flowing through piping D4 increases or decreases according to the opening degree of valve V3, and the temperature of the mixed gas MG1 supplied to the heat exchanger 270 is adjusted.

[0035] Note that pipe D5 does not necessarily have to be branched from pipe D2. That is, the upstream end of pipe D5 may be connected to the combustion furnace 120. The downstream end of pipe D5 may be connected to the heat exchanger 270. In this case, sensor SE1 may be configured to measure the temperature of the mixed gas MG1 in the heat exchanger 270 instead of the temperature of the combustion gas flowing through pipe D4.

[0036] [Heat recovery equipment] As illustrated in Figure 1, the heat recovery equipment 200 includes a steam turbine 210 (turbine), a generator 220, a condenser 230, a plurality of heaters 240, a deaerator 250, a boiler 260, and a heat exchanger 270.

[0037] The steam turbine 210 is connected to the generator 220 via a shaft 211. The steam turbine 210 is configured to rotate using steam generated in the boiler 260, which in turn rotates the generator 220 via the shaft 211. This allows the generator 220 to generate electricity. The steam used to rotate the steam turbine 210 is supplied to the condenser 230 through piping D11.

[0038] The steam turbine 210 may include multiple extraction stages. As illustrated in Figure 1, the steam turbine 210 may include six extraction stages E1 to E6. Steam at different temperatures is extracted from each of the extraction stages E1 to E6. The temperature of the steam extracted from the extraction stages E1 to E6 decreases in the order of extraction stages E1 to E6.

[0039] The condenser 230 is configured to cool the steam discharged from the steam turbine 210 and condense it into water. The water condensed in the condenser 230 (condensate) is sent through pipes D12 and D13 to at least one of the heater 240 and the heat exchanger 270.

[0040] The piping D12 is equipped with, in order from upstream, a pump P, a valve V4, and multiple heaters 240. Pump P is controlled based on a control signal from controller Ctr and is configured to send condensate downstream. Valve V4 is controlled based on a control signal from controller Ctr and is configured to open and close the piping D12 before and after valve V4 to adjust the opening degree.

[0041] From the middle of piping D12 (the section between pump P and valve V4), piping D13 branches off and extends. The downstream end of piping D13 is connected to the middle of piping D12 (the downstream section of the multiple heaters 240). In piping D13, from upstream to downstream, are valve V5, heat exchanger 270, and sensor SE2 (measuring section). Therefore, condensate discharged from condenser 230 can be supplied to the multiple heaters 240 through piping D12, and also to the heat exchanger 270 through piping D12 and D13.

[0042] Valve V5 is controlled based on a control signal from controller Ctr and is configured to adjust the opening degree by opening and closing piping D13 before and after valve V5. Sensor SE2 is a thermometer configured to measure the temperature of condensate (condensate after preheating in heat exchanger 270 (preheated water)) flowing through piping D13 downstream of heat exchanger 270. Sensor SE2 is configured to transmit the measured temperature data to controller Ctr.

[0043] The multiple heaters 240 are configured to preheat the condensate with steam extracted from two or more of the multiple extraction stages. In the example in Figure 1, the multiple heaters 240 include five heaters 241 to 245. Heaters 241 to 243 are installed on piping D12 in this order from upstream. Heaters 244 and 245 are installed on piping D14 connecting the deaerator 250 and the boiler 260 in this order from upstream.

[0044] Heater 241 may be configured to preheat the condensate flowing through piping D12 with steam extracted from extraction stage E6, for example. Heater 242 may be configured to preheat the condensate flowing through piping D12 with steam extracted from extraction stage E5, for example. Heater 243 may be configured to preheat the condensate flowing through piping D12 with steam extracted from extraction stage E4, for example. Heater 244 may be configured to preheat the condensate (saturated water described later) flowing through piping D14 with steam extracted from extraction stage E2, for example. Heater 245 may be configured to preheat the condensate (saturated water described later) flowing through piping D14 with steam extracted from extraction stage E1, for example. That is, the heating temperature of the condensate by heater 241, which is located furthest upstream in the flow direction of the condensate in piping D12 and D14, is the lowest, and the heating temperature of the condensate by heater 245, which is located furthest downstream in the same flow direction, is the highest. In the example shown in Figure 1, the steam extracted from extraction stages E1 to E6 does not necessarily have to be used to preheat the condensate.

[0045] The deaerator 250 is configured to remove gases (e.g., oxygen, carbon dioxide, etc. dissolved in the preheated water) contained in the condensate (preheated water) preheated in the multiple heaters 240 or heat exchangers 270. The deaerator 250 is configured to saturate the preheated water by heating it with steam and to deaerate the dissolved gases from the preheated water. Steam extracted from the extraction stage E3 may be used as the steam to heat the preheated water in the deaerator 250. The saturated water produced in the deaerator 250 is supplied to the boiler 260 through piping D14.

[0046] The boiler 260 is configured to heat saturated water with heat from the combustion of fuel (e.g., coal) to produce high-temperature, high-pressure steam. The steam produced in the boiler 260 is supplied to the steam turbine 210 through piping D15.

[0047] The heat exchanger 270 is configured to preheat the condensate flowing through the piping D13 using heat from outside the heat recovery equipment 200 system. In the example shown in Figure 1, the heat exchanger 270 is configured to heat the condensate by exchanging heat between the combustion gas CG (mixed gas MG1) generated in the combustion furnace 120 and the condensate (heat transfer medium).

[0048] [controller] As illustrated in Figure 2, the controller Ctr has a reading unit M1, a storage unit M2, a processing unit M3, and an instruction unit M4 as functional modules. These functional modules are merely a convenient division of the controller Ctr's functions into multiple modules, and do not necessarily mean that the hardware constituting the controller Ctr is divided into such modules. Each functional module is not limited to being implemented by program execution, but may also be implemented by a dedicated electrical circuit (e.g., a logic circuit) or an integrated circuit (ASIC: Application Specific Integrated Circuit) that integrates these.

[0049] The reading unit M1 is configured to read a program from a computer-readable recording medium RM. The recording medium RM stores programs for operating each part of the manufacturing system 1 (e.g., blower F, pump P, valves V1-V5, etc.). The recording medium RM may be, for example, a semiconductor memory, an optical recording disk, a magnetic recording disk, or a magneto-optical recording disk. The recording medium RM may be built into the same enclosure as the controller Ctr, or it may be a separate enclosure (so-called external type) from the enclosure containing the controller Ctr.

[0050] The storage unit M2 is configured to store various types of data. For example, the storage unit M2 may store programs read from the recording medium RM by the reading unit M1, setting data input from the operator via an external input device (not shown), etc. The storage unit M2 may also store temperature data measured by sensors SE1 and SE2, for example.

[0051] The processing unit M3 is configured to process various types of data. For example, the processing unit M3 may be configured to generate control signals for controlling each part of the manufacturing system 1 based on various types of data stored in the storage unit M2.

[0052] The processing unit M3 may perform a process to adjust the opening degree of valve V3 so that the temperature Tw of the preheated water measured by the sensor SE2 becomes a predetermined target temperature Tset (for example, about 158°C). The processing unit M3 may, for example, use PID control to adjust the opening degree of valve V3 so that the deviation ΔT (= Tset - Tw) between the target temperature Tset and the temperature Tw becomes 0.

[0053] Alternatively, the processing unit M3 may perform a process to adjust the opening degree of valve V3 by cascade control so that the temperature Tw of the preheated water becomes a predetermined target temperature Tw_set. For example, the processing unit M3 calculates the deviation ΔTw (=Tw_set-Tw) between the target temperature Tw_set and the temperature Tw. Next, the processing unit M3 calculates the target temperature Tg_set (Tg_set=K·ΔTw) of the mixed gas MG1 supplied to the heat exchanger 270 by multiplying the deviation ΔTw by a predetermined proportionality constant K. Next, the processing unit M3 calculates the deviation ΔTg (=Tg_set-Tg) between the temperature Tg of the mixed gas MG1 measured by sensor SE2 and the target temperature Tg_set. After that, the processing unit M3 may, for example, perform PID control of the opening degree of valve V3 so that the deviation ΔTg becomes 0.

[0054] The instruction unit M4 is configured to transmit the control signals generated in the processing unit M3 to each part of the manufacturing system 1.

[0055] The hardware of the controller Ctr may consist of, for example, one or more control computers. The controller Ctr may include, as a hardware configuration, the circuit C1 illustrated in Figure 3. The circuit C1 may consist of electrical circuit elements. The circuit C1 may include, for example, a processor C2, a memory C3 (storage unit), a storage C4 (storage unit), a driver C5, and an input / output port C6. The processor C2 executes a program in cooperation with at least one of the memory C3 and the storage C4, and performs signal input and output via the input / output port C6, thereby configuring each of the above-mentioned functional modules. The memory C3 and the storage C4 function as storage unit M2. The driver C5 is a circuit that drives each part of the manufacturing system 1. The input / output port C6 performs signal input and output between the driver C5 and each part of the manufacturing system 1.

[0056] The manufacturing system 1 may have one controller Ctr, or it may have a controller group (control unit) composed of multiple controllers Ctr. In the latter case, each of the above functional modules may be implemented by one controller Ctr, or by a combination of two or more controllers Ctr. If the controller Ctr is composed of multiple computers (circuit C1), each of the above functional modules may be implemented by one computer (circuit C1), or by a combination of two or more computers (circuit C1). The controller Ctr may include multiple processors C2. In this case, each of the above functional modules may be implemented by one processor C2, or by a combination of two or more processors C2.

[0057] [Effect] In the above example, the temperature of the combustion gas CG (mixed gas MG1) introduced into the heat exchanger 270 is controlled so that the temperature of the preheated water after heating in the heat exchanger 270 reaches a predetermined target temperature. Therefore, even if impurities accumulate on the outer surface (gas-side heat transfer surface) of the piping D13 through which the condensate flows (i.e., the portion of piping D13 located inside the heat exchanger 270) and the efficiency of heat exchange between the combustion gas CG and the condensate decreases over time, the valve V3 is controlled so that the temperature of the combustion gas CG introduced into the heat exchanger 270 increases in proportion to the decreased efficiency. Thus, when heating the condensate in the heat exchanger 270 using the heat of the combustion gas CG discharged from the combustion furnace 120, it is possible to heat the condensate to a predetermined target temperature even if the heat exchanger 270 deteriorates over time, by simply controlling the opening of the valve V3.

[0058] In the above example, the heat from the combustion gas CG generated in the combustion furnace 120 is recovered in the heat exchanger 270. Therefore, the thermal energy can be effectively utilized in other equipment (heat recovery equipment 200) equipped with the heat exchanger 270.

[0059] As shown in the above example, even when the temperature of the combustion gas CG discharged from the combustion furnace 120 fluctuates significantly, the temperature of the combustion gas CG is adjusted when it is introduced into the heat exchanger 270. Therefore, it becomes possible to produce biomass solid fuel BF of various carbonization degrees in a single fuel production facility 100, and it becomes possible to effectively recover the heat from the combustion gas CG while responding to the temperature fluctuations of the combustion gas CG that may occur during the production of biomass solid fuel BF.

[0060] As shown in the above example, the heat exchanger 270 is configured to exchange heat with the combustion gas CG using at least a portion of the condensate produced in the condenser 230 as a heat transfer medium. Therefore, the thermal energy of the combustion gas CG produced in the combustion furnace 120 can be effectively utilized for power generation.

[0061] Based on the above examples, the biomass raw material BM can be a molded body formed by pressurizing powdered biomass into a predetermined shape. In this case, the handling of the biomass raw material BM becomes easier.

[0062] In the above example, a portion of the high-temperature combustion gas CGa can be introduced into the heating section 116, and the remainder of the high-temperature combustion gas CGa can be introduced into the heat exchanger 270. Therefore, the amount of high-temperature combustion gas CGa introduced into the heating section 116 is less compared to the case where the entire amount of high-temperature combustion gas CGa from the combustion furnace 120 is introduced into the heating section 116. As a result, the size of the blower F located downstream of the heating section 116 can be reduced. Consequently, the power consumption of the blower F is suppressed, making it possible to increase productivity in the production of biomass solid fuel BF.

[0063] [Differentiation] The disclosures herein should be considered in all respects to be illustrative and not restrictive. Various omissions, substitutions, and modifications may be made to the above examples without departing from the claims and the gist thereof.

[0064] (1) As illustrated in Figure 4, instead of the high-temperature combustion gas CGa discharged from the combustion furnace 120, waste heat from another heat source (for example, waste heat from other equipment such as factory waste heat) may be supplied to the heating section 116. As illustrated in Figure 4, the high-temperature combustion gas CGa discharged from the combustion furnace 120 may be introduced into the heat exchanger 270 through piping D6 (flow path). In the middle of piping D6, piping D7 is connected to supply air (cooling gas) from the outside to piping D6.

[0065] A valve V6 (adjustment unit) is provided in the piping D7. Valve V6 is controlled based on a control signal from the controller Ctr and is configured to open and close the piping D7 before and after valve V6 to adjust the opening degree. By controlling the opening degree of valve V6 by the controller Ctr, the flow rate of air flowing through piping D7 is adjusted. That is, the amount of air mixed with the high-temperature combustion gas CGa flowing through piping D6 increases or decreases according to the opening degree of valve V6, and the temperature of the combustion gas CG (mixed gas MG2 of high-temperature combustion gas CGa and air) supplied to the heat exchanger 270 is adjusted. The mixed gas MG2 contains at least high-temperature combustion gas CGa.

[0066] In the example shown in Figure 4, sensor SE1 is configured to measure the temperature of the mixed gas MG2 supplied to the heat exchanger 270. In the example shown in Figure 4, the low-temperature combustion gas CGb discharged from the heating section 116 is not introduced into the heat exchanger 270.

[0067] As shown in the example in Figure 4, even if the efficiency of heat exchange between the combustion gas CG and the condensate decreases over time, valve V6 is controlled so that the flow rate of air mixed with the high-temperature combustion gas CGa decreases in proportion to the decreased efficiency. Therefore, when heating the condensate in the heat exchanger 270 using the heat of the combustion gas CG discharged from the combustion furnace 120, it is possible to heat the condensate to a predetermined target temperature even if the heat exchanger 270 deteriorates over time, by simply adjusting the amount of air mixed with the high-temperature combustion gas CGa.

[0068] As shown in the example in Figure 4, waste heat from other heat sources (for example, waste heat from other equipment such as factory waste heat) can be supplied to the heating unit 116. This waste heat is typically around 400°C to 700°C, which is lower than the high-temperature combustion gas CGa discharged from the combustion furnace 120. In other words, by supplying a relatively small amount of heat to the heating unit 116, the biomass raw material BM can be heated, making it possible to make the heating unit 116 more compact.

[0069] As shown in the example in Figure 4, by supplying waste heat from another heat source (for example, waste heat from other equipment such as factory waste heat) to the heating unit 116, the pyrolysis gas PG generated in the cylindrical body 111 is burned in the combustion furnace 120, generating high-temperature combustion gas CGa. In other words, a relatively large amount of high-temperature combustion gas CGa can be obtained using the waste heat, which has a relatively small amount of heat. Therefore, the relatively small amount of heat is amplified, and a relatively large amount of heat is recovered in the heat recovery equipment 200. This makes it possible to perform heat recovery through economies of scale, which could not be done due to profitability constraints because the amount of heat recovered would be small if only factory waste heat was used. Note that the amount of heat in the high-temperature combustion gas CGa may be, for example, about 10 times that of the waste heat.

[0070] As shown in the example in Figure 4, the heat source introduced to the heating unit 116 and the heat source introduced to the heat exchanger 270 are separate systems. Therefore, since each system can be controlled independently, it is possible to simplify and facilitate the operation of the manufacturing system 1.

[0071] In the example shown in Figure 4, the point where pipe D7 merges with pipe D6 may be near the upstream end of pipe D6. In this case, the portion of pipe D6 downstream of the point where it merges with pipe D7 can be made of a material with relatively low heat resistance. This makes it possible to reduce the cost of pipe D6.

[0072] In addition, in the example in Figure 4, as in the example in Figure 1, a portion of the high-temperature combustion gas CGa discharged from the combustion furnace 120 may be introduced into the heating section 116.

[0073] (2) As illustrated in Figure 5, the fuel manufacturing equipment 100 may further include a classifier 130 and a crusher 140.

[0074] The classifier 130 is controlled based on a control signal from the controller Ctr and is configured to sieve the biomass solid fuel BF discharged from the discharge port of the discharge section 115 into sieved material with a particle size larger than a predetermined size and unsieved material. The classifier 130 may be, for example, a vibrating screen. The sieved material (biomass solid fuel BF with a relatively large particle size) may be shipped externally as a product, for example. The unsieved material (biomass solid fuel BF with a relatively small particle size) may be transported to the crusher 140 for use as fuel in other equipment.

[0075] The crusher 140 is controlled based on a control signal from the controller Ctr and is configured to crush the sieved material into a fine powder. The crusher 140 may be, for example, a vertical crusher. The fine biomass solid fuel BF produced by the crusher 140 is transported to another device and used as fuel in that device. The other device may be, for example, the boiler 260 of the heat recovery equipment 200. That is, the boiler 260 may heat saturated water by burning the fine biomass solid fuel BF produced by the crusher 140 as fuel.

[0076] In the example shown in Figure 5, the biomass solid fuel BF generated in the heating device 110 is pulverized into a fine powder by the crusher 140, and the fine powdered biomass solid fuel BF is burned as fuel in the boiler 260 to generate electricity. As a result, the consumption of fuel (e.g., coal) used in the boiler 260 is reduced. Consequently, the cost of power generation can be reduced. In particular, by sorting the biomass solid fuel BF generated in the heating device 110 that is unsuitable for shipment to external customers (biomass solid fuel BF with relatively small particle size) using the classifier 130 and supplying it to the boiler 260, the cost of power generation can be further reduced, and dust generation from the accumulated biomass solid fuel BF can be prevented.

[0077] [Other examples] Example 1. An example of a biomass solid fuel production system comprises a heating device configured to heat biomass raw materials to produce biomass solid fuel; a combustion furnace configured to burn the pyrolysis gas generated by heating the biomass raw materials in the heating device to produce combustion gas; a heat exchanger configured to exchange heat between the combustion gas produced in the combustion furnace and a heat transfer medium to heat the heat transfer medium; a measuring unit configured to measure the temperature of the heat transfer medium after it has been heated in the heat exchanger; a adjusting unit configured to adjust the temperature of the combustion gas supplied to the heat exchanger; and a control unit. The control unit is configured to perform a process to control the adjusting unit so that the temperature measured by the measuring unit becomes a predetermined target temperature.

[0078] In this case, the temperature of the combustion gas introduced into the heat exchanger is controlled so that the temperature of the heat transfer medium after heating in the heat exchanger reaches a predetermined target temperature. Therefore, even if impurities accumulate on the heat transfer surface (gas-side heat transfer surface) of the heat exchanger that does not come into contact with the heat transfer medium, and the efficiency of heat exchange between the combustion gas and the heat transfer medium decreases over time, the control unit is controlled so that the temperature of the combustion gas introduced into the heat exchanger increases in proportion to the decrease in efficiency. Consequently, when heating the heat transfer medium in the heat exchanger using the heat of the exhaust gas discharged from the combustion furnace, it is possible to heat the heat transfer medium to a predetermined target temperature even if the heat exchanger deteriorates over time.

[0079] In the system of Example 1, the heat from the combustion gases generated in the combustion furnace is recovered in the heat exchanger. Therefore, it becomes possible to effectively utilize the thermal energy in other equipment equipped with a heat exchanger (heat recovery equipment).

[0080] Incidentally, the amount of pyrolysis gas generated by heating biomass raw materials varies depending on the degree of carbonization of the biomass solid fuel to be obtained. As a result, the temperature fluctuation of the combustion gas discharged from the combustion furnace can be large. However, according to the system in Example 1, even if the temperature fluctuation of the combustion gas discharged from the combustion furnace is large, the temperature of the combustion gas is adjusted when it is introduced into the heat exchanger. Therefore, it becomes possible to produce biomass solid fuels of various carbonization degrees in a single manufacturing facility, and it is also possible to effectively recover the heat from the combustion gas while responding to the temperature fluctuations of the combustion gas that may occur during the production of biomass solid fuel.

[0081] In this book, "degree of carbonization" refers to the degree of carbonization of biomass solid fuel, and can be evaluated by, for example, solid (material) yield and energy yield. Solid (material) yield is defined as the ratio of the amount of product produced to the amount of raw material supplied (solid (material) yield = amount of product produced / amount of raw material supplied × 100), and the lower the solid (material) yield, the more advanced the carbonization of the biomass solid fuel is considered to be. Energy yield is defined as the ratio of the calorific value of the product to the calorific value of the raw material (energy yield = calorific value of the product / calorific value of the raw material × 100), and the lower the energy yield, the more advanced the carbonization of the biomass solid fuel is considered to be. In this book, a "high" degree of carbonization refers to a solid (material) yield of 80% or less, or an energy yield of 90% or less. On the other hand, in this book, a "low" degree of carbonization refers to a solid (material) yield of 85% or more, or an energy yield of 95% or more.

[0082] Example 2. In the system of Example 1, the heating device includes a cylindrical body with one end into which biomass raw material is fed and the other end from which biomass solid fuel is discharged, a heating section arranged to cover the outer circumference of the cylindrical body and configured to heat the biomass raw material flowing inside the cylindrical body with high-temperature combustion gas discharged from the combustion furnace, and a first flow path configured to introduce low-temperature combustion gas discharged from the heating section into a heat exchanger. The combustion furnace includes a second flow path configured to introduce high-temperature combustion gas into the heating section and a third flow path configured to introduce high-temperature combustion gas into the first flow path or the heat exchanger. The control unit may include a flow control valve configured to adjust the flow rate of high-temperature combustion gas flowing through the third flow path according to its opening. In this case, even if the efficiency of heat exchange between the combustion gas and the heat transfer medium decreases over time, the flow control valve is controlled so that the flow rate of high-temperature combustion gas mixed with the low-temperature combustion gas increases in proportion to the decreased efficiency. Therefore, by using a simple method of controlling the opening degree of the flow control valve, it is possible to obtain the same effects as the system in Example 1.

[0083] Example 3. In the system of Example 1, the heating device includes a cylindrical body with one end into which biomass raw material is fed and the other end from which biomass solid fuel is discharged, and a heating section arranged to cover the outer circumference of the cylindrical body and configured to heat the biomass raw material flowing inside the cylindrical body. The combustion furnace includes a flow path configured to introduce high-temperature combustion gas discharged from the combustion furnace into a heat exchanger, and the control unit may be configured to supply cooling gas to the flow path or heat exchanger to cool the high-temperature combustion gas flowing through the flow path. In this case, even if the efficiency of heat exchange between the combustion gas and the heat transfer medium decreases over time, the control unit controls the flow rate of cooling gas mixed with the high-temperature combustion gas to decrease in accordance with the decreased efficiency. Therefore, it is possible to obtain the same effects as the system of Example 1 by a simple method of adjusting the amount of cooling gas mixed with the high-temperature combustion gas.

[0084] Example 4. Any system from Examples 1 to 3 further comprises a boiler configured to generate steam by the combustion of fuel, a turbine configured to rotate by the steam generated in the boiler, a generator configured to generate electricity by the rotation of the turbine, and a condenser configured to cool the steam discharged from the turbine to produce condensate, wherein a heat exchanger is configured to exchange heat with the combustion gas using at least a portion of the condensate produced in the condenser as a heat transfer medium. In this case, the thermal energy of the combustion gas produced in the combustion furnace can be effectively utilized for power generation.

[0085] Example 5. The system of Example 4 may further include a crusher configured to crush the biomass solid fuel produced by the heating device and supply it to the boiler as fuel. In this case, the biomass solid fuel produced by the heating device is burned in the boiler and used for power generation. Therefore, the consumption of fuel used in the boiler (e.g., coal) is reduced. Thus, it is possible to reduce the cost of power generation. In particular, the cost of power generation can be further reduced by supplying to the boiler biomass solid fuel produced by the heating device that is not suitable for shipment to external parties as a commodity.

[0086] Example 6. In any of the systems in Examples 1 to 5, the biomass raw material may be a molded body in which powdered biomass is pressure-molded into a predetermined shape. In this case, handling of the biomass raw material becomes easier. [Explanation of Symbols]

[0087] 1...Manufacturing system, 100...Fuel manufacturing equipment, 110...Heating device, 111...Cylindrical body, 111a...One end, 111b...Other end, 116...Heating section, 120...Combustion furnace, 140...Crusher, 200...Heat recovery equipment, 210...Steam turbine (turbine), 220...Generator, 230...Condenser, 260...Boiler, 270...Heat exchanger, Ctr...Controller (control unit), D2...Piping (second flow path), D2, D5...Piping (third flow path), D3, D4...Piping (first flow path), SE2...Sensor (measuring unit), D6...Piping (flow path), V3...Valve (adjustment unit, flow control valve), V6...Valve (adjustment unit).

Claims

1. A heating device configured to produce biomass solid fuel by heating biomass raw materials, A combustion furnace configured to generate combustion gas by burning the pyrolysis gas produced by heating biomass raw materials in a heating device, A heat exchanger configured to exchange heat between the combustion gas generated in the combustion furnace and the heat transfer medium to heat the heat transfer medium, A measuring unit configured to measure the temperature of the heat transfer medium after it has been heated in the heat exchanger, A control unit configured to adjust the temperature of the combustion gas supplied to the heat exchanger, It includes a control unit, A biomass solid fuel production system, wherein the control unit is configured to perform a process to control the adjustment unit so that the temperature measured by the measuring unit becomes a predetermined target temperature.

2. The heating device is A cylindrical body including one end into which the biomass raw material is fed and the other end from which the biomass solid fuel is discharged, A heating unit is provided, which is positioned to cover the outer circumference of the cylindrical body and is configured to heat the biomass raw material flowing inside the cylindrical body with high-temperature combustion gas discharged from the combustion furnace, among the combustion gases. The system includes a first flow path configured to introduce low-temperature combustion gas discharged from the heating section into the heat exchanger, The aforementioned combustion furnace is A second flow path configured to introduce the high-temperature combustion gas into the heating section, The system includes a third flow path configured to introduce the high-temperature combustion gas into the first flow path or the heat exchanger, The system according to claim 1, wherein the adjustment unit includes a flow control valve configured to adjust the flow rate of the high-temperature combustion gas flowing through the third passage according to the opening degree.

3. The heating device is A cylindrical body including one end into which the biomass raw material is fed and the other end from which the biomass solid fuel is discharged, It includes a heating unit that is positioned to cover the outer circumference of the cylindrical body and configured to heat the biomass raw material flowing inside the cylindrical body, The combustion furnace includes a flow path configured to introduce high-temperature combustion gas discharged from the combustion furnace into the heat exchanger. The system according to claim 1, wherein the adjustment unit is configured to supply a cooling gas to the flow path or the heat exchanger for cooling the high-temperature combustion gas flowing through the flow path.

4. A boiler configured to generate steam by burning fuel, A turbine configured to rotate by steam generated in the boiler, A generator configured to generate electricity by the rotation of the turbine, The system further comprises a condenser configured to cool the steam discharged from the turbine and produce condensate, The system according to any one of claims 1 to 3, wherein the heat exchanger is configured to exchange heat with the combustion gas using at least a portion of the condensate produced in the condenser as the heat transfer medium.

5. The system according to claim 4, further comprising a pulverizer configured to pulverize the biomass solid fuel produced by the heating device and supply it to the boiler as fuel.

6. The system according to any one of claims 1 to 3, wherein the biomass raw material is a molded body obtained by pressurizing powdered biomass into a predetermined shape.

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