Method and device for controlling temperature inside a supercharged fluidized bed incinerator

Abstract

To control an in-furnace temperature of a fluidized incinerator by adjusting an in-system pressure in a supercharged fluidized incinerator and adjusting a temperature of compressed air to be supplied to an air preheater from a supercharger.SOLUTION: In an in-furnace temperature control method and a control device, in a supercharged fluidized furnace 2, a pressure of compressed gas sent from a supercharger is adjusted and a heat exchange amount in an air preheater 30 is adjusted, by adjusting an opening of an adjustment valve 48 disposed in the middle of an exhaust gas passage 43 bypassing the supercharger 50 disposed in the middle of the exhaust gas passage.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a supercharged fluidized bed incinerator and a method for controlling the supercharged fluidized bed incinerator, which controls the fluidization state of a fluidized bed material flowing within the incinerator. [Background technology]

[0002] A fluidized bed incinerator is an incinerator that creates a fluidized bed by fluidizing a fluidizing medium such as sand placed in the furnace using air pumped in from the bottom of the furnace, and then agitates and incinerates the materials to be incinerated, such as sewage sludge or municipal waste, that are placed in the heated fluidized bed. The fluidized bed incinerator changes depending on the air supplied to the incinerator (also called supply air, combustion air, fluidizing air, or preheated air), the amount of material to be incinerated, auxiliary fuel, etc., and the temperature and pressure inside the incinerator. Stabilizing the fluidized bed and optimizing the combustion conditions is important for increasing the combustion efficiency of the material to be incinerated.

[0003] For example, in a fluidized bed incinerator, a method has been proposed in which the amount of air supplied into the furnace to fluidize the bed material is adjusted according to the brightness inside the furnace, the amount of material to be incinerated, the temperature, the oxygen concentration, or the pressure inside the furnace (see Patent Document 1). In addition, a method has been proposed for stabilizing combustion in a fluidized bed incinerator by estimating the increase or decrease in moisture content of sewage sludge cake based on the oxygen concentration of the exhaust gas and the moisture concentration in the upper part of the furnace, and adjusting the amount of air supplied to the furnace, the temperature inside the furnace, the amount of material to be incinerated supplied to the furnace, etc. based on the estimated results (see Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3108742 [Patent Document 2] Japanese Patent Application Laid-Open No. 2004-125332 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional bubbling fluidized bed incinerators, the pressure inside the system was almost constant regardless of the operating conditions. Therefore, when the load, which is the supply amount of material to be incinerated, increases or decreases, the calorific value and volume of the exhaust gas at the incinerator outlet also increases or decreases, and the temperature of the preheated air in the air preheater, which exchanges heat, increases or decreases in accordance with the increase or decrease in the calorific value and volume of the exhaust gas. For example, during low loads, excess air is supplied to serve as fluidizing air, which lowers the temperature of the preheated air in the air preheater that exchanges heat with the exhaust gas from the fluidized incinerator. This increases the amount of fuel supplied to raise the preheated air temperature to a specified temperature (set temperature), resulting in a deterioration in fuel efficiency. Conversely, during high loads, the preheated air temperature rose, and the preheated air was cooled by an air preheater, and water was injected into the incinerator (use of power and water), and the amount of incineration (material to be incinerated, e.g., sludge) was adjusted (reduced).

[0006] The present invention aims to provide a method for controlling the temperature of preheated air in a turbocharged fluidized bed incinerator, which can reduce the use of unnecessary equipment, auxiliary fuel, power, and water by adjusting the operating conditions and sending instructions from a control unit to the turbocharger to increase or decrease the turbocharger rotation speed, and by adjusting the pressure within the system. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, the method for controlling the temperature inside the furnace of a supercharged fluidized bed incinerator of the present invention will be described below. [1] An incinerator that is supplied with materials to be incinerated and air, burns the materials while causing them to flow together with a fluidized bed material, and discharges exhaust gas; a turbine that is provided in the course of an exhaust gas path through which the exhaust gas discharged from the incinerator flows; a compressor that is provided in the course of a path through which air supplied to the incinerator flows and that operates in conjunction with the turbine; a supercharger that rotates the turbine using the flow of the exhaust gas discharged from the incinerator and also rotates the compressor to compress the air; and an air preheater that is provided in the exhaust gas path and in a position in the path of air supplied from the supercharger to the incinerator, and that heats the air by exchanging heat between the exhaust gas and the air. In a supercharged fluidized bed furnace, The aforementioned Exhaust gas route Among these, Bypass the turbocharger route It is in the middle of Exhaust gas By adjusting the opening of the control valve, The aforementioned It adjusts the pressure of the compressed air sent from the turbocharger, The aforementioned Adjusting the amount of heat exchange in the air preheater and controls the temperature inside the incinerator. do A method for controlling temperature inside a furnace, characterized in that, if the pressure inside the incinerator is within an upper or lower limit range, it is determined whether the inlet temperature, which is the temperature of the preheated air at the inlet of the incinerator, is within a set range, and if the inlet temperature is lower than the set range, the pressure of the air supplied to the air preheater is increased, and if the inlet temperature is higher than the set range, the pressure of the air supplied to the air preheater is decreased. [ 2 〕 Incineration Inside the furnace of Pressure is within the upper and lower limits Outside In case, Incineration Inside the furnace of When the pressure falls below the lower limit The aforementioned Air preheater Air supplied to Increase the pressure of Incineration Inside the furnace of When the pressure exceeds the upper limit The aforementioned Air preheater Air supplied to The pressure of descent The method for controlling the temperature inside the furnace according to [1], [ 3 〕 The turbocharged fluidized furnace further includes a white smoke prevention device that performs heat exchange between the exhaust gas sent out from the turbocharger and air, and a white smoke prevention fan that supplies air to the white smoke prevention device, Due to changes in the pressure of the compressed air supplied by the turbocharger, The incinerator It is judged whether the amount of air supplied to the inside is within the set range, and the amount of air supplied is greater than the set amount of air. Few If so, The aforementioned Compressed air supply path from the turbocharger , the above Bypass route connecting the air supply route from the white smoke prevention fan of On the way air Adjust the opening of the control valve to increase the amount of compressed air, and if the amount of supplied air is greater than the set amount of air, of the air The opening of the control valve is adjusted to reduce the amount of compressed air. [1] or [2] The method for controlling the temperature inside a furnace according to claim 1. [ 4 ) Pressure adjustment, In the exhaust gas path, For turbochargers Incineration Sends exhaust gas from the furnace route and , the above turbocharger The above From the turbine Exhaust gas discharge do Bypass road connecting the route of On the way of the exhaust gas The control valve is adjusted to adjust the opening of the control valve. [1] or [2] The method for controlling the temperature inside a furnace according to claim 1.

[0008] [ 5 〕 An incinerator that is supplied with materials to be incinerated and air, burns the materials while causing them to flow together with a fluidized bed material, and discharges exhaust gas; a turbine that is provided in the course of an exhaust gas path through which the exhaust gas discharged from the incinerator flows; a compressor that is provided in the course of a path through which air supplied to the incinerator flows and that operates in conjunction with the turbine; a supercharger that rotates the turbine using the flow of the exhaust gas discharged from the incinerator and also rotates the compressor to compress the air; and an air preheater that is provided in the exhaust gas path and in a position in the path of air supplied from the supercharger to the incinerator, and that heats the air by exchanging heat between the exhaust gas and the air. Supercharged fluidized bed furnace Established , The aforementioned Exhaust gas route Among these, Bypass the turbocharger route It is in the middle of Exhaust gas By adjusting the opening of the control valve, The aforementioned It adjusts the pressure of the compressed air sent from the turbocharger, The aforementioned Adjusting the amount of heat exchange in the air preheater and controls the temperature inside the incinerator. do control A control device that operates based on a program If the pressure inside the incinerator is within an upper or lower limit range, the control device determines whether the inlet temperature, which is the temperature of the preheated air at the inlet of the incinerator, is within a set range, and if the inlet temperature is lower than the set range, increases the pressure of the air supplied to the air preheater, and if the inlet temperature is higher than the set range, decreases the pressure of the air supplied to the air preheater. [ 6 〕 Incineration Inside the furnace of Pressure is within the upper and lower limits Outside In case, Incineration Inside the furnace of When the pressure falls below the lower limit The aforementioned Air preheater Air supplied to Increase the pressure of Incineration Inside the furnace of When the pressure exceeds the upper limit The aforementioned Air preheater Air supplied to The pressure of descent The present invention is characterized in that 5 ] A control device according to the above. [ 7 〕 The turbocharged fluidized furnace further includes a white smoke prevention device that performs heat exchange between the exhaust gas sent out from the turbocharger and air, and a white smoke prevention fan that supplies air to the white smoke prevention device, Due to changes in the pressure of the compressed air supplied by the turbocharger, The incinerator It is judged whether the amount of air supplied to the inside is within the set range, and the amount of air supplied is greater than the set amount of air. Few If so, The aforementioned Compressed air supply path from the turbocharger , the above Bypass route connecting the air supply route from the white smoke prevention fan of On the way air Adjust the opening of the control valve to increase the amount of compressed air, and if the amount of supplied air is greater than the set amount of air, of the air The opening of the control valve is adjusted to reduce the amount of compressed air. [5] or [6] The control device according to [ 8 ) Pressure adjustment, In the exhaust gas path, For turbochargers Incineration Sends exhaust gas from the furnace route and , the above turbocharger The above From the turbine Exhaust gas discharge do Bypass road connecting the route of On the way of the exhaust gas The control valve is adjusted to adjust the opening of the control valve. [5] or [6] The control device described in [Effects of the Invention]

[0009] According to the present invention, the preheated air temperature can be adjusted by adjusting the pressure inside the turbocharged fluidized bed incinerator. During low-load operation, the system pressure can be increased to reduce the amount of auxiliary fuel used, and during high-load operation, the system pressure can be reduced, eliminating the need for an air cooler and the need to inject water into the incinerator or adjust the amount of incineration. This reduces initial costs (cost of air cooler) and running costs. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram showing an example of an incineration system including a control device for a fluidized incinerator according to a first embodiment. FIG. [Figure 2] FIG. 2 is a cross-sectional view showing an example of the structure of an air preheater. [Figure 3] FIG. 2 is an explanatory diagram showing the flow of calculations executed by the control device. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, this embodiment will be described with reference to the drawings. FIG. 1 shows an example of an incineration system including a control device for a fluidized bed incinerator according to the first embodiment, and FIG. 2 shows an example of the structure of an air preheater. The incineration system 1 shown in Figure 1 consists of a fluidized bed incinerator 2, a sludge (cake) supply device 10, a water supply device 15, a fuel supply device 20, an air preheater 30, a dust collector 40, a turbocharger 50, a startup blower 60, a white smoke prevention fan 70, a white smoke prevention (preheater) device 75, a flue gas treatment tower 80 equipped with a chimney, and a control device 90. The incineration system 1 also has thermometers 23 and 24, a pressure gauge 25, air preheater air volume measuring instruments 26 and 27, and a turbocharger rotation speed measuring instrument 28. For example, in an embodiment of the present invention, the fluidized incinerator 2 is a turbocharged fluidized incinerator. The fluidized incinerator 2 supplies heated compressed air to the incinerator 2 and burns the materials to be incinerated in the incinerator 2 under high temperature and pressure conditions, thereby increasing the combustion rate and reducing the amount of emissions of harmful substances such as NO. In the following description, the fluidized bed incinerator 2 will also be simply referred to as the incinerator 2.

[0012] The thick solid lines with arrows indicate supply paths (supply pipes) for sludge (cake), auxiliary fuel, air, water, or exhaust gas, and the dashed lines with arrows indicate bypass paths. Thin solid lines with arrows (for example, <1> the line connecting the pressure gauge 25 to the control valve 48 (CV4), <2> the line connecting the control valve 48 (CV4) to the turbocharger rotation speed measuring device 28, <3> the line connecting the turbocharger rotation speed measuring device 28 to the air preheater air amount measuring device 27, <4> the line connecting the air preheater air amount measuring device 27 to the control valve 49 (CV5), <5> the line connecting the thermometer 23 to the control valve 17 (CV2) and the control valve 22 (CV1), <6> the line connecting the control valve 17 (CV2) to the thermometer 24, <7> the line connecting the thermometer 24 to the control valve 47 (CV3), and <8> the line connecting the air preheater air amount measuring device 26 to the control valve 47 (CV3)) indicate signal lines that send control signals from the control device to these control valves. For example, the control device 90 receives a pressure value from the pressure gauge 25, sends an opening command signal to the control valve 48 (CV4) based on the pressure value, and adjusts the opening of the control valve 48.

[0013] The fluidized bed incinerator 2 is equipped with a fluidized bed 3, a preheated air intake 4, and a start-up burner 5 inside the furnace. In addition, there are provided a sludge inlet (not shown) for taking in sludge supplied from a supply line (sludge supply pipe) 11 connected to a sludge (cake) supply device 10, a water (water supply) inlet (not shown) for taking in water (water supply) supplied from a supply line (water supply pipe) 16 connected to a water supply device 15, and a fuel inlet (not shown) for taking in auxiliary fuel supplied from a supply line (fuel supply pipe) 21 connected to a fuel supply device 20. The sludge (cake) supplying device 10 sequentially supplies sewage sludge cakes, which have been sent from a sewage treatment facility and stored in a hopper (not shown), from a supply pipe 11 to the incinerator 2.

[0014] The water supply device 15 adjusts the combustion temperature inside the incinerator 2 by sending water (water injection) into the incinerator 2 from the connected supply pipe 16, and the fuel supply device 20 adjusts the combustion temperature inside the incinerator 2 by sending auxiliary fuel into the incinerator 2 from the connected supply pipe 21. The water supply pipe 16 is provided with a control valve 17 (CV2), and the fuel supply pipe 21 is provided with a control valve 22 (CV1). The control valve 17 (CV2) and the control valve 22 (CV1) are connected to a control device 90, and the opening degree thereof is adjusted in response to a control signal output from the control device 90.

[0015] The thermometer 23 measures the temperature of the fluidized bed 3 provided in the fluidized incinerator 2. The thermometer 23 is connected to the control device 90 and outputs the measured temperature value to the control device 90. The thermometer 24 measures the temperature of the preheated air supplied from the air preheater 30 into the fluidized bed incinerator 2. The thermometer 24 is connected to the control device 90 and outputs the measured temperature value to the control device 90.

[0016] The pressure gauge 25 measures the pressure of the exhaust gas inside the fluidized bed incinerator 2. The pressure gauge 25 is connected to the control device 90 and outputs the measured pressure value to the control device 90. The air preheater air amount measuring instrument 26 measures the amount of compressed air supplied from the turbocharger 50 to the air preheater 30. The air preheater air amount measuring instrument 26 is connected to the control device 90 and outputs the measured compressed air amount value to the control device 90.

[0017] The air preheater air amount measuring instrument 27 measures the amount of compressed air supplied from the turbocharger 50. The air preheater air amount measuring instrument 27 is connected to the control device 90 and outputs the measured compressed air amount value to the control device 90. The rotation speed measuring device 28 measures the rotation speed of the supercharger 50. The rotation speed measuring device 28 is connected to the control device 90 and outputs the measured rotation speed value to the control device 90.

[0018] FIG. 2 is a cross-sectional view showing an example of the structure of an air preheater. The air preheater 30 is composed of a cylindrical housing 30a, and the inside of the housing 30a is divided by a partition plate 30c to provide an upper parallel flow heat exchange chamber 30d and a lower counter flow heat exchange chamber 30e. 30f is the high temperature side tube plate, 30g is the low temperature side tube plate, 30h is the heat transfer tube, 30i is the baffle plate, 30j is the exhaust gas discharge chamber, 30k is the compressed air introduction header that sends compressed air to the upper parallel flow type heat exchange chamber 30d, 30m is the compressed air introduction header that sends compressed air to the lower counter flow type heat exchange chamber 30e, 30n is the thermal fluid discharge header, F1 is the high temperature exhaust gas, and F2 is the low temperature exhaust gas. The high-temperature exhaust gas F1 supplied from the fluidized bed incinerator 2 to the air preheater 30 via the supply line 58 is separated from the upper heat exchange chamber 30d by the high-temperature side tube plate 30f, and the exhaust gas discharge chamber 30j is separated from the upper heat exchange chamber 30d and the lower counterflow heat exchange chamber 30e by the low-temperature side tube plate 30g. A large number of heat transfer tubes 30h are installed inside the heat exchange chambers (heat exchange chambers 30d and 30e), and their upper and lower ends are connected to the high-temperature side tube plate 30f and the low-temperature side tube plate 30g, respectively. The high-temperature exhaust gas F1 that flows into the heat exchange chambers (heat exchange chambers 30d and 30e) through the heat transfer tubes 30h is sent from the fluidized bed incinerator 2 via a supply path 58. A partition plate 30c is attached to the middle of the heat exchange chamber, dividing the heat exchange chamber into an upper heat exchange chamber 30d and a lower heat exchange chamber 30e. Several baffle plates 30i are arranged in the upper heat exchange chamber 30d and the lower heat exchange chamber 30e.

[0019] In the upper parallel flow heat exchange chamber 30d, the air and exhaust gas flow in the same direction, and the heat exchange volume is small, so the air discharged from the air preheater is difficult to heat up. On the other hand, in the lower counter flow heat exchange chamber 30e, the air and exhaust gas flow in opposite directions, and the heat exchange volume is large, so the air coming out is easily heated. At the thermal fluid discharge header 30n at the position where the supply line 29 is connected, the preheated air flowing from the upper parallel flow heat exchange chamber and the preheated air flowing from the lower counter flow heat exchange chamber are mixed, and the mixed preheated air is supplied to the incinerator.

[0020] In the air preheater 30, which is an embodiment of the present invention, heat is exchanged between exhaust gas sent from the fluidized bed incinerator 2 via the supply line 58 and compressed air sent from the turbocharger 50 via the supply line 56, the branch supply line 56a, and the branch supply line 56b. The heat-exchanged air is then supplied from the preheated fluid discharge header 30n through the supply path 29 to the incinerator 2 through the preheated air intake 4.

[0021] The dust collector 40 separates and recovers solid components such as ash contained in the exhaust gas discharged from the air preheater 30 and fed through the supply path 31, and feeds the exhaust gas from which solid components such as ash have been removed to the turbocharger 50 through the supply path 41. The fed exhaust gas is then fed from the turbocharger 50 to the white smoke preventive device 75 through the supply path 42.

[0022] The turbocharger 50 has a turbine 52 and a compressor 53 connected to a common rotating shaft 51. The turbine 52 receives exhaust gas sent from the dust collector 40 via the supply path 41 to the turbocharger 50 and rotates at high speed, thereby rotating the compressor 53 at high speed. The compressor 53 compresses the air taken in by the turbocharger 50 and sends the compressed air to the air preheater 30 via the supply path 56, the branch supply path 56a, and the branch supply path 56b. In the air preheater 30, heat is exchanged between the exhaust gas and the compressed air, and the heated compressed air is sent to the preheated air intake 4 of the incinerator 2 via the supply path 29.

[0023] A control valve 47 (CV3) is provided between the branch supply path 56a and the branch supply path 56b in the supply path 56. The control valve 47 (CV3) is connected to a control device 90, and its opening is adjusted in response to a control signal output from the control device 90. By adjusting this opening, the amount of compressed air supplied to the branch supply passage 56a supplying air to the upper side of the air preheater 30 and the branch supply passage 56b supplying air to the lower side of the air preheater 30 is adjusted.

[0024] A startup blower 60 supplies air taken in at the start-up of the incineration system 1 from a supply path 61 to the air supply path 56 and from a supply path 62 to the turbocharger 50. Reference numeral 63 denotes a check valve provided in the supply path 62. After startup, when the stage has come where the exhaust gas from the fluidized bed incinerator 2 can secure fluidizing air from the compressor 53 of the turbocharger 50, the supply of atmospheric air (air) from the startup blower 60 is stopped, and switching is made so that atmospheric air is supplied to the turbocharger 50 from a supply line 65. 66 is a control valve provided in the supply line 65, and is connected to a control device 90, and its opening is adjusted in response to a control signal output from the control device 90.

[0025] The white smoke prevention fan 70 sends the air it has taken in to the white smoke prevention device 75 via a supply path 71. The white smoke preventer 75 heats the air sent in from the white smoke prevention fan 70, which takes in atmospheric air, by exchanging heat with the exhaust gas discharged from the turbocharger 50 and supplied via the supply path 42. The heated air is sent to the flue gas treatment tower 80. In the flue gas treatment tower 80, air pollutants such as sulfur oxides and soot contained in the flue gas are removed from the flue gas.

[0026] A bypass passage 43 provided between the supply passage 41 and the supply passage 42 is provided with a turbocharger exhaust gas bypass control valve 48 (CV4). The turbocharger exhaust gas bypass control valve 48 (CV4) (hereinafter simply referred to as the control valve) is connected to a control device 90, and the opening degree thereof is adjusted in response to a control signal output from the control device 90. By adjusting this opening, the amount of exhaust gas sent from the supply passage 41 to the turbocharger 50 is adjusted. For example, when the opening of the exhaust gas bypass control valve 48 (CV4) is increased, part of the exhaust gas sent to the turbocharger 50 from the supply path 41 that supplies exhaust gas from the dust collector 40 to the turbocharger flows to the supply path 42 that supplies exhaust gas from the turbocharger 50 to the white smoke inhibitor 75, and therefore the amount of exhaust gas sent from the supply path 41 to the turbocharger 50 is reduced. The pressure in the compressed air supply path after the compressor 53, the air preheater 30, and the incinerator 2 is adjusted according to the amount of exhaust gas sent from the supply path 41 to the turbocharger 50. For example, when it is desired to increase the pressure of the supply air in the air preheater 30, the opening of the control valve 48 (CV4) is reduced to increase the rotation speed of the turbocharger 50. Conversely, when it is desired to decrease the pressure of the supply air, the opening of the control valve 48 (CV4) is increased to decrease the rotation speed of the turbocharger.

[0027] Incidentally, when the pressure of the supply air in the air preheater 30 increases, the heat exchange from the exhaust gas of the incinerator 2 to the supply air increases, and the incinerator inlet temperature T2 rises. This is because the supply air pressure increases and the fluid density increases, thereby increasing the heat exchange capacity. Conversely, when the pressure of the supply air in the air preheater 30 decreases, the heat exchange from the exhaust gas of the incinerator 2 to the supply air decreases, and the incinerator inlet temperature T2 drops. This means that the supply air pressure drops and the fluid density decreases, thereby decreasing the heat exchange capacity. Therefore, the incinerator inlet temperature T2 can be controlled by adjusting the pressure of the supply air in the air preheater 30.

[0028] Moreover, a bypass path 57 provided between the air supply path 56 and the supply path 71 is provided with an excess air control valve 49 (CV5). The surplus air control valve 49 (CV5) is connected to a control device 90, and the opening degree thereof is adjusted in response to a control signal of an opening degree command outputted from the control device 90. When adjusting the pressure of the supply air, the pressure of the compressed air sent from the supercharger 50 to the supply passage 56 is adjusted by adjusting this opening, and the amount of compressed air is adjusted.

[0029] For example, when the mass flow rate of compressed air is constant, the volumetric flow rate decreases when the pressure is high, so by increasing the opening of the surplus air control valve 49 (CV5) to release the surplus air from the bypass path 57 to the supply path 71 and releasing the pressure, the volumetric flow rate of compressed air sent from the supply path 56 to the air preheater 30 is increased. On the other hand, when the pressure is low, the volumetric flow rate increases, so by reducing the opening of the surplus air control valve 49 (CV5) to maintain the pressure without releasing the surplus air from the bypass path 57 to the supply path 71, the volumetric flow rate of compressed air sent from the supply path 56 to the air preheater 30 is reduced. In other words, pressure changes occur to control the inlet temperature of the fluidized air at the incinerator, but the volumetric flow rate of the fluidized air that accompanies this changes affects the amount of fluidized air. Therefore, by adjusting the opening of the excess air control valve 49 (CV5), the amount of fluidized air can be kept within a certain range, the fluidized state of the fluidized bed in the fluidized incinerator can be stabilized, and the combustion state can be made appropriate.

[0030] The control device 90 includes, for example, a PLC (Programmable Logic Controller) and operates based on a control program executed by the PLC. The control device 90 receives signals from various sensors (such as a thermometer, a pressure gauge, an air preheater air amount measuring device, and a turbocharger rotation speed measuring device), and controls various devices (regulating valves) by sending control signals corresponding to the received signals to the various devices using a built-in control program.

[0031] FIG. 3 is a flowchart illustrating an example of the operation of the control device illustrated in FIG. The present invention controls the preheated air temperature by adjusting the pressure in a supercharged fluidized bed incinerator. For example, the control device controls the temperature according to the following flow. Start: The following process is executed repeatedly at a predetermined interval. S1: Determine whether the furnace pressure P1 is within the range from the lower limit P1min to the upper limit P1max, and if it is within the range, proceed to S2. If it is outside the range, proceed to S7. S2: Determine whether the incinerator inlet temperature T2 is at the set temperature T2sp. The set temperature T2sp may have a certain range. S3: If the determination of S2 is Yes, it is determined whether the combustion air volume F2 has reached the set air volume F2sp. Note that the set air volume F2sp may have a certain range. S4: If the determination of S2 is No, it is determined whether the inlet temperature T2 of the incinerator is lower than the set temperature T2sp. S5: If the determination of S4 is Yes, the supercharger rotation speed R1 is increased by opening and closing the control valve 48 (CV4), and the pressure downstream of the supply line 56 and later is increased. Then, proceed to the determination in S3. S6: If it is No (T2 > T2sp) in S4, the supercharger rotation speed R1 is decreased by opening and closing the control valve 48 (CV4), and the pressure downstream of the supply line 56 and later is decreased. Then, proceed to the determination in S3. S7: If it is No in S1, it is determined whether P1 is lower than the lower limit value P1min. S8: If it is Yes in S7, the supercharger rotation speed R1 is increased by opening and closing the control valve 48 (CV4), and the pressure downstream of the supply line 56 and later is increased. Then, proceed to the determination in S3. S9: If it is No in S7 (P1 exceeds the upper limit value P1max), the supercharger rotation speed R1 is decreased by opening and closing the control valve 48 (CV4), and the pressure downstream of the supply line 56 and later is decreased. Then, proceed to the determination in S3. S10: If it is No in S3, a determination is made by comparing the combustion air volume F2 with the set air volume F2sp. S11: If F2 < F2sp in S10, the opening degree of the excess air control valve 49 (CV5) is increased, the combustion air volume F2 is allowed to escape to the supply line 71, the pressure of the combustion air volume F2 is released, and the volumetric flow rate of the combustion air volume F2 is increased. Then, proceed to End. S12: If it is not F2 < F2sp but F2 > F2sp in S10, the opening degree of the excess air control valve 49 (CV5) is decreased, the pressure of the combustion air volume F2 is maintained without allowing the combustion air volume F2 to escape to the supply line 71, and the volumetric flow rate of the combustion air volume F2 is decreased. Then, proceed to End. End: After the determination in S3 and the operations in S11 and S12 are completed, return to Start.

[0032] By periodically performing the above steps, it is possible to adjust the pressure of the air preheater 30 in the incineration system 1 using a supercharged fluidized bed incinerator and control the preheated air temperature. When the load, which is the amount of material supplied to be incinerated, increases or decreases, the preheated air temperature, which adjusts the temperature inside the furnace, is controlled; when the load is low and the temperature drops due to the amount of preheated air, the preheated air temperature is increased by adjusting the pressure, thereby achieving fuel-efficient operation that limits the amount of fuel supplied; and conversely, when the load is high and the temperature inside the furnace rises, the preheated air temperature is decreased by adjusting the pressure, thereby lowering the temperature inside the furnace. This eliminates the need for water injection into the furnace and also eliminates the need for an air cooler. [Explanation of symbols]

[0033] 1: Incineration system 2: Fluidized bed incinerator 10: Sludge supply device 15:Water supply device 17: Control valve (CV2) 20: Fuel supply device 22: Control valve (CV1) 23: Thermometer 24: Thermometer 25: Pressure gauge 26: Air preheater air volume measuring instrument 27: Air preheater air volume measuring instrument 28: Turbocharger rotation speed measuring instrument 30: Air preheater 40: Dust collector 47: Control valve (CV3) 48: Control valve (CV4) 49: Control valve (CV5) 50: Turbocharger 60: Start-up blower 70: White smoke prevention fan 75: White smoke preventer 80: Flue gas treatment tower 90: Control device

Claims

1. An incinerator that is supplied with materials to be incinerated and air, burns the materials to be incinerated while fluidizing them together with a fluidized medium, and discharges exhaust gas; a turbocharger comprising a turbine provided in the middle of an exhaust gas path through which exhaust gas discharged from the incinerator flows, and a compressor provided in the middle of a path through which air supplied to the incinerator flows and linked to the turbine, the turbocharger rotating the turbine by the flow of exhaust gas discharged from the incinerator and rotating the compressor to compress the air; an air preheater that is installed in the exhaust gas path and in the path of air supplied from the turbocharger to the incinerator, and that heats the air by exchanging heat between the exhaust gas and the air; In a supercharged fluidized bed furnace equipped with An in-furnace temperature control method for controlling the temperature inside the incinerator by adjusting the opening of an exhaust gas control valve located in the middle of a path that bypasses the turbocharger among the exhaust gas paths, thereby adjusting the pressure of compressed air sent from the turbocharger and adjusting the heat exchange amount in the air preheater, If the pressure inside the incinerator is within the upper and lower limit ranges, it is determined whether the inlet temperature, which is the temperature of the preheated air at the inlet of the incinerator, is within a set range, and if the inlet temperature is lower than the set range, the pressure of the air supplied to the air preheater is increased, and if the inlet temperature is higher than the set range, the pressure of the air supplied to the air preheater is decreased.

2. A method for controlling temperature inside a furnace as described in claim 1, characterized in that when the pressure inside the incinerator is outside the upper or lower limit range, the pressure of the air supplied to the air preheater is increased when the pressure inside the incinerator falls below the lower limit, and the pressure of the air supplied to the air preheater is decreased when the pressure inside the incinerator exceeds the upper limit.

3. The supercharged fluidized bed furnace is a white smoke suppressor that performs heat exchange between the exhaust gas sent out from the turbocharger and air; a white smoke prevention fan that supplies air to the white smoke prevention device; 3. A method for controlling an incinerator temperature according to claim 1, further comprising: determining whether the amount of air supplied to the incinerator is within a set range based on a change in the pressure of the compressed air supplied from the turbocharger; and, if the amount of air supplied is less than the set amount of air, adjusting the aperture of an air adjustment valve located in the middle of a bypass route connecting the compressed air supply path from the turbocharger and the air supply path from the white smoke prevention fan to increase the amount of compressed air; and, if the amount of air supplied is greater than the set amount of air, adjusting the aperture of the air adjustment valve to decrease the amount of compressed air.

4. A method for controlling the temperature inside the furnace as described in claim 1 or 2, characterized in that the pressure is adjusted by adjusting the opening of the exhaust gas control valve located in the middle of a bypass path connecting a path that sends exhaust gas from the incinerator to the turbocharger and a path that discharges exhaust gas from the turbine of the turbocharger.

5. An incinerator that is supplied with materials to be incinerated and air, burns the materials to be incinerated while causing them to flow together with a fluidized medium, and discharges exhaust gas; a turbocharger comprising a turbine provided in the middle of an exhaust gas path through which exhaust gas discharged from the incinerator flows, and a compressor provided in the middle of a path through which air supplied to the incinerator flows and linked to the turbine, the turbocharger rotating the turbine by the flow of exhaust gas discharged from the incinerator and rotating the compressor to compress the air; an air preheater that is installed in the exhaust gas path and in the path of air supplied from the turbocharger to the incinerator, and that heats the air by exchanging heat between the exhaust gas and the air; The fluidized bed furnace is provided with A control device that operates based on a control program that adjusts the pressure of compressed air sent from the turbocharger by adjusting the opening of an exhaust gas control valve located in the middle of a path that bypasses the turbocharger among the exhaust gas paths, adjusts the heat exchange amount in the air preheater, and controls the temperature inside the incinerator, If the pressure inside the incinerator is within the upper and lower limit ranges, a control device is provided which determines whether the inlet temperature, which is the temperature of the preheated air at the inlet of the incinerator, is within a set range, and if the inlet temperature is lower than the set range, increases the pressure of the air supplied to the air preheater, and if the inlet temperature is higher than the set range, decreases the pressure of the air supplied to the air preheater.

6. A control device as described in Claim 5, characterized in that when the pressure inside the incinerator is outside the upper or lower limit range, the pressure of the air supplied to the air preheater is increased when the pressure inside the incinerator falls below the lower limit, and the pressure of the air supplied to the air preheater is decreased when the pressure inside the incinerator exceeds the upper limit.

7. The supercharged fluidized bed furnace is a white smoke suppressor that performs heat exchange between the exhaust gas sent out from the turbocharger and air; a white smoke prevention fan that supplies air to the white smoke prevention device; 7. A control device according to claim 5 or 6, characterized in that it determines whether the amount of air supplied to the incinerator is within a set range based on a change in the pressure of the compressed air supplied from the turbocharger, and if the amount of air supplied is less than the set air amount, it adjusts the aperture of an air adjustment valve located midway through a bypass route connecting the compressed air supply path from the turbocharger and the air supply path from the white smoke prevention fan to increase the amount of compressed air, and if the amount of air supplied is greater than the set air amount, it adjusts the aperture of the air adjustment valve to decrease the amount of compressed air.

8. 7. The control device according to claim 5 or 6, characterized in that the pressure is adjusted by adjusting the opening of the exhaust gas control valve located in the middle of a bypass path that connects a path that sends exhaust gas from the incinerator to the turbocharger and a path that discharges exhaust gas from the turbine of the turbocharger.

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