Gasifier Control System

Abstract

To provide a fluidized bed gasification furnace capable of producing a high-convenience gas.SOLUTION: A fluidized bed gasification furnace 1 comprises: a fluidized bed part 10 formed by placing a fluidizing medium on a furnace bottom plate 10A provided inside the furnace; a freeboard part 11 provided above the fluidized bed part 10 inside the furnace; a temperature information acquisition part 12 for acquiring temperature information indicating a temperature in the freeboard part 11; and a first gasifying agent supply part 13 for supplying a first gasifying agent containing steam to the freeboard part 11 such that the temperature in the freeboard part 11 becomes a predetermined first set value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fluidized bed gasification furnace having a fluidized bed section and a freeboard section. [Background technology]

[0002] Conventionally, fluidized bed gasifiers have been used in which a fluidizing gas is fed from the bottom of a fluidizing medium such as silica sand packed inside the gasifier to form a fluidized bed, and the material to be treated is gasified on this fluidized bed. Technology related to such fluidized bed gasifiers is described in Patent Document 1, the source of which is shown below.

[0003] Patent Document 1 describes a fluidized-bed gasifier that uses a fluidizing gas to form a fluidized bed inside a gasifier to gasify fuel and produce combustible gas. In this fluidized-bed gasifier, steam is generated in a boiler using the combustible gas produced in the gasifier, and part of the combustible gas at the gasifier outlet is sucked in, and the mixed gas, which is a mixture of the steam and the combustible gas, is supplied into the gasifier as the fluidizing gas. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-131820 Summary of the Invention [Problem to be solved by the invention]

[0005] In the fluidized-bed gasification system described in Patent Document 1, fluidizing gas is supplied to the fluidized bed from below to increase the temperature of the fluidized bed, but the temperature of the freeboard section above the fluidized bed in the combustion furnace is not controlled. This can lead to variations in the proportions of the main components of the gas generated in the freeboard section (e.g., hydrogen, carbon monoxide, carbon dioxide, etc.), which can reduce the convenience of the gas.

[0006] Therefore, there is a demand for a fluidized bed gasifier that produces gas with high usability. [Means for solving the problem]

[0007] The present invention Gasifier Control System The characteristic configuration of the present invention is a fluidized bed section formed by placing a fluidized medium on a furnace bottom plate provided in a furnace, a freeboard section provided above the fluidized bed section in the furnace, and a temperature information acquisition section that acquires temperature information indicating the temperature in the freeboard section. before The free board section Oxygen and a first gasifying agent supply unit that supplies a first gasifying agent containing water vapor; a fluidized-bed gasification furnace provided with a steam flow rate control valve that is provided upstream of the first gasifying agent supply section and that controls the flow rate of the steam, and a gasification furnace control system that controls operation of the fluidized-bed gasification furnace, wherein the control unit comprises: a supply amount setting section that sets a supply amount of the first gasifying agent to be supplied to the freeboard section so that a temperature in the freeboard section becomes a predetermined first set value, the supply amount setting section determining whether a measurement result of the temperature of the freeboard section is less than the first set value, and when the measurement result of the temperature of the freeboard section is less than the first set value, setting the supply amount of the steam to reduce the supply amount of the steam in the first gasifying agent; and a supply amount control section that controls the steam flow rate control valve so that the supply amount of the steam becomes the amount set by the supply amount setting section. The point is that it is equipped with the following.

[0008] With this characteristic configuration, it is possible to control the components of the gas generated in the fluidized bed section and efficiently gasify the components of the gas generated in the fluidized bed section. Also, the control method is simple because it is only necessary to control the supply amount of the first gasifying agent containing steam so that the temperature of the freeboard section becomes the first set value. In this way, with this fluidized bed gasifier, it is possible to generate highly convenient gas. Furthermore, by increasing the amounts of water vapor and oxygen in the first gasifying agent, it is possible to reduce unnecessary components such as nitrogen in the air. In this case, the volume of the generated gas is reduced by the amount of unnecessary components contained in the first gasifying agent, which allows the size of the component equipment to be reduced and eliminates the need for a device to remove nitrogen from the generated gas.

[0009] Preferably, the steam is supplied from a boiler that operates by utilizing the heat of the gas produced in the furnace.

[0010] This configuration makes it possible to effectively utilize surplus steam generated in the boiler. Also, since there is no need to install a dedicated boiler to generate steam for use in the fluidized-bed gasifier, it becomes possible to utilize steam at low cost.

[0013] The temperature information acquisition unit further acquires sand layer temperature information indicating the temperature of the sand layer constituting the fluidized bed portion, before From below the fluidized bed portion to the fluidized bed portion Oxygen and The gasification system further includes a second gasification agent supply unit that supplies a second gasification agent containing water vapor. The supply amount setting unit sets the supply amount of the second gasifying agent so that the temperature of the sand layer becomes a predetermined second set value. This is preferable.

[0014] With this configuration, the second gasifying agent is supplied from below the fluidized bed, which prevents the sand layer from burning, thereby enabling stable gasification in the fluidized bed.

[0015] It is also preferable that a plurality of the first gasifying agent supply units are provided in the freeboard unit.

[0016] With this configuration, the first gasifying agent supply units can be distributed in the freeboard section, which prevents localized high temperature areas from being formed inside the furnace, thereby suppressing the generation of clinker, slag, etc. inside the furnace. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram showing a gasification furnace control system equipped with a fluidized bed gasification furnace. [Figure 2] 10 is an example of a map for setting the supply amount of a first gasifying agent. [Figure 3] 10 is an example of a map for setting the supply amount of a second gasifying agent. [Figure 4] FIG. 1 is a diagram showing the process in a fluidized bed gasifier. [Figure 5] FIG. 10 is a diagram showing the relationship between the temperature of the freeboard section and the concentration of gas generated in the furnace. DETAILED DESCRIPTION OF THE INVENTION

[0018] A fluidized-bed gasifier gasifies raw materials such as wood chips and waste plastics using oxygen and steam to generate hydrogen gas, carbon monoxide gas, and light hydrocarbon gases such as methane and ethylene. These gases also include heavy hydrocarbons such as tar. The fluidized-bed gasifier according to the present invention is configured to produce clean gas with a low hydrocarbon gas content. The fluidized-bed gasifier 1 of this embodiment will now be described.

[0019] 1 is a diagram showing a schematic configuration of a gasification furnace control system 100 that controls the operation of a fluidized bed gasification furnace 1. The gasification furnace control system 100 includes the fluidized bed gasification furnace 1, a control unit 2 that controls the operation of the fluidized bed gasification furnace 1, and a boiler 3 that operates using gas produced by the fluidized bed gasification furnace 1.

[0020] As shown in Figure 1, the fluidized bed gasifier 1 is configured to include a fluidized bed section 10, a freeboard section 11, a temperature information acquisition section 12, a first gasifying agent supply section 13, and a second gasifying agent supply section 14. The control unit 2 is configured to include a supply amount setting section 21, a supply amount setting map storage section 22, and a supply amount control section 23. The boiler 3 is configured to include a boiler body 3A, a flue 3B, a steam valve 3C, a superheater 3D, and an economizer 3E. Each functional section of the control unit 2 is constructed using hardware or software, or both, with a CPU as its core component in order to perform processes related to combustion in the fluidized bed gasifier 1.

[0021] The fluidized bed section 10 is formed by placing a fluidized bed material on a hearth plate 10A installed in the furnace. The inside of the furnace is the interior of the fluidized-bed gasifier 1. In this embodiment, the hearth plate 10A has multiple aeration nozzles (not shown) through which a gasifying agent is supplied, and is configured in a state of inclination from the outer edge toward the center. The fluidized bed material is a fluid material, and sand (e.g., silica sand) is used as the fluidized bed material. Therefore, a sand layer 10B is formed in the fluidized bed section 10. The sand layer 10B is heated to approximately 750°C to 800°C and incinerates the biomass fuel 4, including wood chips, placed on the sand layer 10B. In addition, air is supplied from a forced draft device 5 below the fluidized bed section 10, especially at the start of combustion. The supply of air from the forced draft device 5 is stopped when the temperature of the fluidized bed section 10 of the fluidized-bed gasifier 1 stabilizes. Furthermore, when the temperature of the freeboard section 11 is rising, air is supplied into the furnace from the first gasifying agent supply section 13 and the air supply section 15, but once combustion stabilizes, the supply of air is stopped by the flow control valve 44.

[0022] The freeboard section 11 is provided above the fluidized bed section 10 within the furnace. The fluidized bed gasification furnace 1 is provided vertically, and the above-mentioned fluidized bed section 10 is provided on the lower side within the furnace. The freeboard section 11 corresponds to the space above the fluidized bed section 10 within the furnace.

[0023] The temperature information acquisition unit 12 acquires temperature information indicating the temperature in the freeboard section 11. For example, the temperature information acquisition unit 12 can be configured using a temperature sensor (e.g., a thermocouple) that measures the temperature in the freeboard section 11. Furthermore, by providing the temperature information acquisition units 12 at multiple locations in the freeboard section 11, it is possible to detect the temperature distribution in the freeboard section 11 in detail. In this embodiment, two temperature information acquisition units 12 are provided in the freeboard section 11. If one of the two temperature information acquisition units 12 is temperature information acquisition unit 12A and the other is temperature information acquisition unit 12B, the temperature information acquisition unit 12A and the temperature information acquisition unit 12B are provided at positions in the freeboard section 11 at different heights. In this embodiment, the temperature information acquisition unit 12A is provided below the temperature information acquisition unit 12B, one of the temperature information acquisition units 12A is disposed between a pair of first gasifying agent supply units 13 arranged in the vertical direction (between the first gasifying agent supply unit 13A and the first gasifying agent supply unit 13B), and the other temperature information acquisition unit 12B is disposed between the first gasifying agent supply unit 13 (first gasifying agent supply unit 13B) and the air supply unit 15. The temperature information (measurement result) acquired by the temperature information acquisition unit 12 is transmitted to the supply amount setting unit 21.

[0024] In this embodiment, the temperature information acquiring unit 12 acquires sand layer temperature information indicating the temperature of the sand layer 10B. The temperature information acquiring unit 12 that measures the temperature of the sand layer 10B will be described as temperature information acquiring unit 12C when distinguished from the temperature information acquiring units 12A and 12B that acquire the temperature information of the freeboard unit 11 described above. The measurement result by the temperature information acquiring unit 12C (i.e., sand layer temperature information) is transmitted to the supply amount setting unit 21.

[0025] When combustion begins in the fluidized-bed gasifier 1, gas is generated within the furnace as described above. At least a portion of this gas is used to operate the boiler 3. A flue 3B is provided in the boiler body 3A of the boiler 3, through which the gas from the fluidized-bed gasifier 1 is introduced, and water that has been deaerated and treated with chemicals is also supplied. This water is heated by the gas introduced into the flue 3B and is blown out as steam (wet steam) from a steam valve 3C above the boiler body 3A. The steam blown out from the steam valve 3C is introduced into the superheater 3D. The steam introduced into the superheater 3D is superheated using the gas discharged from the flue 3B, becoming superheated steam (dry steam). The gas used in the superheater 3D is introduced into the economizer 3E and used to preheat the water to be supplied to the boiler body 3A.

[0026] The supply amount setting unit 21 sets the supply amount of the first gasifying agent to be supplied to the freeboard section 11 so that the temperature in the freeboard section 11 becomes a predetermined first set value. The first gasifying agent to be supplied to the freeboard section 11 is a gas that is supplied to the freeboard section 11 to generate clean gas in the furnace as described above, and is a gas that contains water vapor. In this embodiment, the first gasifying agent further contains oxygen.

[0027] In this embodiment, the steam constituting the first gasifying agent is superheated steam obtained by heating the steam blown out from the boiler 3. Here, the superheated steam is steam at several hundred degrees Celsius and in a low-oxygen state. Therefore, by introducing such superheated steam into the freeboard section 11, it becomes possible to perform temperature control and also to prevent oxidation of the gas generated in the furnace. Furthermore, by maintaining the temperature in the freeboard section 11 at a predetermined temperature (first setting section), it becomes possible to generate clean gas. The supply amount setting map storage unit 22 pre-stores a supply amount of the first gasifying agent that can make the temperature of the freeboard section 11 equal to the first setting value, based on the current temperature in the freeboard section 11.

[0028] 2 shows an example of a supply rate setting map used to set the supply rate of the first gasifying agent. The example of FIG. 2 shows the relationship between the temperature TA of the portion of the freeboard section 11 where the temperature information acquisition unit 12A is provided, the temperature TB of the portion of the freeboard section 11 where the temperature information acquisition unit 12B is provided, and the supply rate of the first gasifying agent supplied from the first gasifying agent supply unit 13, which will be described later. In this embodiment, a plurality of (two) first gasifying agent supply units 13 are provided in the freeboard section 11. Therefore, in FIG. 2, as the supply rate of the first gasifying agent by the first gasifying agent supply units 13, a supply rate FA of the first gasifying agent by one first gasifying agent supply unit 13A of the two first gasifying agent supply units 13 and a supply rate FB of the first gasifying agent by the other first gasifying agent supply unit 13B of the two first gasifying agent supply units 13 are individually shown.

[0029] The supply amount setting unit 21 is transmitted, as temperature information indicating the temperature in the freeboard unit 11, the measurement results of the temperature information acquiring unit 12A and the measurement results of the temperature information acquiring unit 12B. Based on these measurement results, the supply amount setting unit 21 sets the supply amount FA of the first gasifying agent by the first gasifying agent supply unit 13A and the supply amount FB of the first gasifying agent by the first gasifying agent supply unit 13B from a supply amount setting map for the first gasifying agent stored in the supply amount setting map storage unit 22. For example, when the temperature TA is T1°C and the temperature TB is T2°C, the supply amount setting unit 21 sets A1 as the supply amount FA and B2 as the supply amount FB. Information indicating the supply amount FA and the supply amount FB set by the supply amount setting unit 21 is transmitted to the supply amount control unit 23, which will be described later.

[0030] In this embodiment, the supply amount setting unit 21 also sets the supply amount of the second gasifying agent to be supplied to the sand layer 10B so that the temperature of the sand layer 10B becomes a predetermined second set value. The second gasifying agent to be supplied to the sand layer 10B is a gas containing water vapor that is supplied to the sand layer 10B to suppress burning of the sand layer 10B and generate clean gas in the furnace. In this embodiment, the second gasifying agent also further contains oxygen.

[0031] In this embodiment, the steam (steam) constituting the second gasifying agent also uses superheated steam from the boiler 3. The supply amount setting map storage unit 22 stores in advance a supply amount of the second gasifying agent that can make the temperature of the sand layer 10B equal to the second set value, relative to the current temperature in the sand layer 10B.

[0032] An example of a supply amount setting map used to set the supply amount of the second gasifying agent is shown in Fig. 3. The example in Fig. 3 shows the relationship between the temperature TC of the portion of the sand layer 10B where the temperature information acquisition unit 12C is provided and the supply amount of the second gasifying agent supplied from the second gasifying agent supply unit 14, which will be described later. In Fig. 3, this is shown as the supply amount FC of the second gasifying agent supplied by the second gasifying agent supply unit 14.

[0033] The supply amount setting unit 21 is transmitted the measurement result of the temperature information acquisition unit 12C as temperature information indicating the temperature in the sand layer 10B. Based on this measurement result, the supply amount setting unit 21 sets the supply amount FC of the second gasifying agent to be supplied by the second gasifying agent supply unit 14 from the supply amount setting map for the second gasifying agent stored in the supply amount setting map storage unit 22. For example, when the temperature TC is T3°C, the supply amount setting unit 21 sets C3 as the supply amount FC. Information indicating the supply amount FC set by the supply amount setting unit 21 is transmitted to the supply amount control unit 23, which will be described later.

[0034] The supply amount control unit 23 controls the amount of the first gasifying agent supplied by the first gasifying agent supply unit 13 and the amount of the second gasifying agent supplied by the second gasifying agent supply unit 14 based on the flow control valve 40. In this embodiment, upstream of the first gasifying agent supply unit 13A, a flow control valve 41A that controls the flow rate of steam constituting the first gasifying agent supplied from the first gasifying agent supply unit 13A to the freeboard section 11 and a flow control valve 41B that controls the flow rate of oxygen constituting the first gasifying agent supplied from the first gasifying agent supply unit 13A to the freeboard section 11 are provided as the flow control valves 40. Note that the flow control valves 41A and 41B may be collectively referred to as flow control valves 41.

[0035] Furthermore, on the upstream side of the first gasifying agent supply section 13B, there are provided, as flow control valves 40, a flow control valve 42A that controls the flow rate of steam constituting the first gasifying agent supplied from the first gasifying agent supply section 13B to the freeboard section 11, and a flow control valve 42B that controls the flow rate of oxygen constituting the first gasifying agent supplied from the first gasifying agent supply section 13B to the freeboard section 11. The flow control valves 42A and 42B may be collectively referred to as flow control valves 42.

[0036] Furthermore, on the upstream side of the second gasifying agent supply unit 14, there are provided, as flow control valves 40, a flow control valve 43A that controls the flow rate of steam constituting the second gasifying agent supplied from the second gasifying agent supply unit 14 to below the sand layer 10B, and a flow control valve 43B that controls the flow rate of oxygen constituting the second gasifying agent supplied from the second gasifying agent supply unit 14 to below the sand layer 10B. Note that the flow control valves 43A and 43B may be collectively referred to as flow control valves 43.

[0037] The flow rate control valves 40 are each configured using an electric valve. The supply amount control unit 23 adjusts the opening degree of these electric valves (flow rate control valves 40) so that the supply amounts of the first gasifying agent and the second gasifying agent become the supply amounts set by the supply amount setting unit 21.

[0038] The first gasifying agent supply unit 13 supplies a first gasifying agent to the freeboard section 11 so that the temperature in the freeboard section 11 becomes a first set value. In this embodiment, the freeboard section 11 is provided with a plurality of first gasifying agent supply units 13 (first gasifying agent supply unit 13A and first gasifying agent supply unit 13B). In this embodiment, the first gasifying agent supply unit 13A is provided below the first gasifying agent supply unit 13B. In this embodiment, when the freeboard section 11 is viewed horizontally, the first gasifying agent supply unit 13A, the temperature information acquisition unit 12A, the first gasifying agent supply unit 13B, and the temperature information acquisition unit 12B are provided in this order from bottom to top. However, this order can be changed depending on the configuration of the fluidized bed gasifier 1.

[0039] As described above, the flow control valves 41A, 42A that control the flow rate of water vapor and the flow control valves 41B, 42B that control the flow rate of oxygen are provided upstream of the first gasifying agent supply unit 13A and the first gasifying agent supply unit 13B, respectively. The openings of the flow control valves 41A, 42A that control the flow rate of water vapor and the flow control valves 41B, 42B that control the flow rate of oxygen are controlled by the supply amount control unit 23, and the first gasifying agent containing water vapor and oxygen is supplied from the first gasifying agent supply unit 13A and the first gasifying agent supply unit 13B.

[0040] The second gasifying agent supplying unit 14 supplies the second gasifying agent to the fluidized bed section 10 from below the fluidized bed section 10 so that the temperature of the sand layer 10B becomes a second set value. In this embodiment, the second gasifying agent supplying unit 14 is provided below the furnace bottom plate 10A in the furnace. Therefore, the second gasifying agent supplying unit 14 is provided below the temperature information acquiring unit 12C that measures the temperature of the sand layer 10B placed on the furnace bottom plate 10A. As described above, the flow control valve 43A that controls the flow rate of steam and the flow control valve 43B that controls the flow rate of oxygen are provided upstream of the second gasifying agent supplying unit 14. The openings of the flow control valve 43A that controls the flow rate of steam and the flow control valve 43B that controls the flow rate of oxygen are controlled by the supply amount control unit 23, and the second gasifying agent containing water vapor and oxygen is supplied from the second gasifying agent supplying unit 14.

[0041] Measurement of the temperature of the freeboard section 11 and supply of the first gasifying agent according to that temperature, and measurement of the temperature of the sand layer 10B and supply of the second gasifying agent according to that temperature are continuously performed during operation of the fluidized bed gasifier 1. Therefore, a feedback control is configured in which the supply amounts of the first gasifying agent and the second gasifying agent are input values, a first set value for the temperature of the freeboard section 11 and a second set value for the temperature of the sand layer 10B are target values, and the temperatures of the freeboard section 11 and the sand layer 10B are output values.

[0042] In particular, in this fluidized bed gasification furnace 1, the supply rates of the first gasifying agent and the second gasifying agent, which are input values, are controlled by PID control based on the deviation, differential value, and integral value calculated from the target values, which are a first set value for the temperature of the freeboard section 11 and a second set value for the temperature of the sand layer 10B, and the output values, which are the temperature of the freeboard section 11 and the temperature of the sand layer 10B. This makes it possible to automatically maintain the environment inside the furnace in a state suitable for generating clean gas.

[0043] Next, the process relating to the temperature control in the fluidized bed gasification furnace 1 will be described with reference to the flowchart of FIG.

[0044] While the fluidized bed gasifier 1 is in operation, the temperature information acquisition unit 12A and the temperature information acquisition unit 12B measure the temperature of the freeboard section 11 and acquire temperature information (step #1). This temperature information (measurement result) is transmitted to the supply amount setting unit 21. The supply amount setting unit 21 determines whether the measurement result of the temperature of the freeboard section 11 is less than a first set value (for example, 1200°C).

[0045] If the measurement result of the temperature of the freeboard section 11 is less than the first set value (Step #2: Yes), the supply amount setting unit 21 sets the supply amount of the first gasifying agent so that the temperature of the freeboard section 11 increases based on the supply amount setting map for setting the supply amount of the freeboard section 11 stored in the supply amount setting map storage unit 22 (Step #3). On the other hand, if the measurement result of the temperature of the freeboard section 11 exceeds the first set value (Step #2: No), the supply amount setting unit 21 sets the supply amount of the first gasifying agent so that the temperature of the freeboard section 11 decreases based on the supply amount setting map for setting the supply amount of the freeboard section 11 stored in the supply amount setting map storage unit 22 (Step #4). Although not shown in FIG. 4, if the measurement result of the temperature of the freeboard section 11 is equal to the first set value (for example, within 1200°C ± 5°C), the processes of Steps #3 and #4 do not need to be performed.

[0046] Furthermore, if the measurement result of the temperature of the freeboard section 11 in step #2 is less than the first set value (step #2: Yes), it is also possible to configure the system to, for example, increase the supply of oxygen or decrease the supply of steam. In this case, adjusting (increasing) the supply of oxygen changes the air ratio and the gas composition, so it is recommended to prioritize adjusting the supply of steam over adjusting the supply of oxygen. Also, it is recommended to adjust the overall air ratio of the sand layer 10B and freeboard section 11 so that it falls within the range of 0.2 to 0.6.

[0047] The supply amount control unit 23 controls the opening degrees of the flow rate control valves 41 and 42 so as to supply the first gasifying agent at the supply amount set by the supply amount setting unit 21 as described above (step #5).

[0048] During or after the supply of the first gasifying agent, the temperature information acquisition unit 12C measures the temperature of the sand layer 10B to acquire temperature information (step #6). This temperature information (measurement result) is transmitted to the supply amount setting unit 21. The supply amount setting unit 21 determines whether the measurement result of the temperature of the sand layer 10B is less than a second set value (e.g., 780°C).

[0049] If the measured temperature of the sand layer 10B is less than the second set value (Step #7: Yes), the supply rate setting unit 21 sets the supply rate of the second gasifying agent so that the temperature of the sand layer 10B increases based on the supply rate setting map for setting the supply rate of the sand layer 10B stored in the supply rate setting map storage unit 22 (Step #8). On the other hand, if the measured temperature of the sand layer 10B exceeds the second set value (Step #7: No), the supply rate setting unit 21 sets the supply rate of the second gasifying agent so that the temperature of the sand layer 10B decreases based on the supply rate setting map for setting the supply rate of the sand layer 10B stored in the supply rate setting map storage unit 22 (Step #9). Although not shown in FIG. 4, if the measured temperature of the sand layer 10B is equal to the second set value (for example, within 780°C ± 5°C), the processes of Steps #8 and #9 do not need to be performed.

[0050] The supply amount control unit 23 controls the opening degree of the flow rate control valve 43 so as to supply the second gasifying agent with the supply amount set by the supply amount setting unit 21 as described above (step #10).

[0051] The series of processes according to steps #1 to #10 described above are continuously performed until combustion ends in the fluidized bed gasification furnace 1 (step #11: No). In the fluidized bed gasification furnace 1, processing is performed along such a flowchart, and it becomes possible to generate clean gas.

[0052] FIG. 5 shows the tendency of the concentration (volume ratio) of the gas generated according to the temperature in the freeboard section 11. In the example of FIG. 5, the gas concentrations of hydrogen, carbon dioxide, carbon monoxide, methane, and hydrocarbon generated when the temperature of the freeboard section 11 is changed from TX to TY are shown (however, TX < TY). As shown in FIG. 5, as the temperature of the freeboard section 11 increases, the gas concentrations of hydrogen, carbon dioxide, and carbon monoxide increase, and the gas concentrations of methane and hydrocarbon decrease. By controlling the temperature of the freeboard section 11 in this way, it becomes possible to control the concentration of the generated gas. Therefore, by controlling the temperature of the freeboard section 11, it becomes possible to generate the desired gas.

[0053] 〔Other Embodiments〕 In the above embodiment, it has been described that the steam is supplied from the boiler 3 that operates using the heat of the gas generated in the furnace, but the steam may be supplied from another boiler different from the boiler 3 that uses the gas of the fluidized bed gasification furnace 1 or from a device other than the boiler.

[0054] In the above embodiment, it has been described that the first gasifying agent and the second gasifying agent are further configured to contain oxygen, but the first gasifying agent and the second gasifying agent can also be configured not to contain oxygen.

[0055] In the above embodiment, it has been explained that the temperature information acquisition unit 12 further acquires sand layer temperature information indicating the temperature of the sand layer 10B that constitutes the fluidized bed section 10, and the second gasifying agent supply unit 14 supplies the second gasifying agent containing steam to the fluidized bed section 10 from below the fluidized bed section 10 so that the temperature of the sand layer 10B reaches a predetermined second set value. However, the fluidized bed gasifier 1 can also be configured so as not to supply the second gasifying agent to the fluidized bed section 10.

[0056] In the above embodiment, it has been described that two first gasifying agent supply units 13 are provided in the freeboard section 11, but it is also possible to provide one first gasifying agent supply unit 13 in the freeboard section 11, or to provide three or more first gasifying agent supply units 13 in the freeboard section 11.

[0057] In the above embodiment, the first gasifying agent supply unit 13A is described as being provided below the first gasifying agent supply unit 13B. However, the first gasifying agent supply unit 13A may be provided above the first gasifying agent supply unit 13B, or the first gasifying agent supply unit 13A and the first gasifying agent supply unit 13B may be provided at the same height.

[0058] In the above embodiment, it has been described that the supply amount setting unit 21 sets the supply amount using the map stored in the supply amount setting map storage unit 22. However, the supply amount setting unit 21 may calculate the supply amount using, for example, a mathematical formula instead of the map, or may calculate the supply amount using a tool other than a mathematical formula.

[0059] In the above embodiment, when the supply amount setting unit 21 determines whether the measurement result of the temperature of the freeboard section 11 is less than the first set value, 1200°C is used as the first set value. However, the first set value is not limited to 1200°C, and can be set within the range of 500°C to 1200°C, for example, depending on the scale and configuration of the fluidized bed gasifier 1.

[0060] In the above embodiment, when the supply amount setting unit 21 determines whether the measurement result of the temperature of the sand layer 10B is less than the second set value, 780°C is used as the second set value. However, the second set value is not limited to 780°C, and can be set within a range of 400°C to 800°C, for example, depending on the scale and configuration of the fluidized bed gasifier 1.

[0061] In the above embodiment, the temperature control in the fluidized-bed gasifier 1 is described as follows: the supply amount control unit 23 controls the apertures of the flow control valves 41 and 42 so as to supply the first gasifying agent at the supply amount set by the supply amount setting unit 21; and controls the aperture of the flow control valve 43 so as to supply the second gasifying agent at the supply amount set by the supply amount setting unit 21. However, the temperature control in the fluidized-bed gasifier 1 can also be performed by, for example, supplying water from the top of the fluidized-bed gasifier 1 and / or recovering heat from the freeboard section 11. The water supply from the top of the fluidized-bed gasifier 1 can be performed by providing a water supply unit that supplies atomized water at the top of the fluidized-bed gasifier 1 and supplying atomized water from this water supply unit. On the other hand, heat recovery from the freeboard section 11 can be performed by, for example, forming a boiler structure by arranging water pipes or the like in the wall surrounding the freeboard section 11, and heating water flowing through the water pipes with heat generated in the freeboard section 11 to generate steam. By supplying water from the furnace top and recovering heat in the freeboard section 11, it is also possible to control the temperature of the fluidized bed gasifier 1.

[0062] It should be noted that the above-described embodiments are merely examples for explaining the present invention, and the present invention is not limited to these embodiments. Therefore, the present invention can be embodied in various forms without departing from the gist of the present invention. [Industrial Applicability]

[0063] The present invention can be used in a fluidized bed gasification furnace equipped with a fluidized bed section and a freeboard section. [Explanation of symbols]

[0064] 1: Fluidized bed gasifier 10: Fluidized bed section 10A: Furnace bottom plate 10B: Sand layer 11: Freeboard section 12:Temperature information acquisition section 13: First gasifying agent supply section 14: Second gasifying agent supply section

Claims

1. a fluidized bed portion formed by placing a fluidized medium on a furnace bottom plate provided in the furnace; a freeboard section provided above the fluidized bed section in the furnace; a temperature information acquiring unit that acquires temperature information indicating the temperature in the freeboard section; a first gasifying agent supply unit that supplies a first gasifying agent containing oxygen and water vapor to the freeboard unit; a steam flow control valve provided upstream of the first gasifying agent supply unit and configured to control the flow rate of the steam; and a gasification furnace control system including a control unit for controlling operation of the fluidized bed gasification furnace, The control unit, a supply amount setting unit that sets a supply amount of the first gasifying agent to be supplied to the freeboard section so that the temperature in the freeboard section becomes a predetermined first set value, the supply amount setting unit determining whether or not a measurement result of the temperature of the freeboard section is less than the first set value, and when the measurement result of the temperature of the freeboard section is less than the first set value, setting the supply amount of the water vapor in the first gasifying agent so as to reduce the supply amount of the water vapor; a supply amount control unit that controls the water vapor flow rate control valve so that the supply amount of water vapor becomes the amount set by the supply amount setting unit; A gasification furnace control system equipped with the following features.

2. The furnace further comprises a boiler that operates using the heat of the gas generated in the furnace, The gasifier control system according to claim 1 , wherein the steam is supplied from the boiler.

3. The temperature information acquisition unit further acquires sand layer temperature information indicating the temperature of the sand layer constituting the fluidized bed portion, a second gasifying agent supply unit configured to supply a second gasifying agent containing oxygen and water vapor to the fluidized bed unit from below the fluidized bed unit, 3. The gasifier control system according to claim 1, wherein the supply amount setting unit sets the supply amount of the second gasifying agent so that the temperature of the sand layer becomes a predetermined second set value.

4. A gasification furnace control system as described in Claim 3, wherein the control unit adjusts the overall air ratio of the sand layer and the freeboard section to be within the range of 0.2 to 0.

6.

5. The gasifier control system according to claim 1 or 2, wherein a plurality of the first gasifying agent supply units are provided in the freeboard unit.

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