Waste treatment equipment

Abstract

To provide a waste treatment facility capable of suppressing an excessive temperature rise in an incinerator while maintaining an autonomous operation of a supercharger.SOLUTION: A waste treatment facility includes: an incinerator for incinerating waste; an air introduction passage for guiding combustion air to the incinerator; an air preheater for heating the combustion air flowing in the air introduction passage by using exhaust gas discharged from the incinerator; a supercharger disposed in the air introduction passage, the supercharger including a compressor that compresses the combustion air and discharges the compressed combustion air to the air preheater side and a turbine rotated by the combustion air heated by the air preheater to drive the compressor; a cooling device disposed between the turbine and the incinerator in the air introduction passage and cooling the combustion air caused to flow out from the turbine; and an air release passage connected to a portion on the downstream side of the cooling device and the upstream side of the incinerator in the air introduction passage.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a waste treatment facility. [Background technology]

[0002] Conventionally, waste treatment facilities for incinerating waste such as sewage sludge are known, as described in Patent Document 1. Patent Document 1 describes a waste treatment facility that includes a combustion furnace for burning waste, a preheater disposed downstream of the combustion furnace, and a turbocharger connected to the preheater. In this waste treatment facility, compressed air discharged from a compressor of the turbocharger is heated in the preheater by exhaust gas from the combustion furnace, and then passes through a turbine of the turbocharger before being supplied to the combustion furnace. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2007-170703 A Summary of the Invention [Problem to be solved by the invention]

[0004] In waste treatment facilities, it is necessary to control the temperature inside the furnace so that it does not exceed the heat-resistant temperature of the incinerator or the heat exchanger located downstream of the incinerator, but the temperature inside the furnace varies depending on the properties of the waste fed into the furnace (e.g., the moisture content of sewage sludge), the amount of auxiliary fuel fed, or the temperature of the combustion air fed into the furnace. For example, if the moisture content of the sewage sludge fed into the furnace is low, and high-temperature combustion air is continuously fed into the furnace, the temperature inside the furnace may exceed the heat-resistant temperature.

[0005] On the other hand, the turbocharged waste treatment facility described in Patent Document 1 uses thermal energy of exhaust gas to supply combustion air to the incinerator using a turbocharger, and if the temperature of the combustion air flowing into the turbine drops too much, it becomes difficult to maintain the independent operation of the turbocharger. Therefore, in conventional turbocharged waste treatment facilities, there was a problem that it was difficult to suppress excessive temperature rise in the incinerator while maintaining the independent operation of the turbocharger.

[0006] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a waste treatment facility that can suppress excessive temperature rise in an incinerator while maintaining independent operation of a turbocharger. [Means for solving the problem]

[0007] A waste treatment facility according to one aspect of the present invention includes an incinerator for incinerating waste, an air introduction path for introducing combustion air to the incinerator, an air preheater for heating the combustion air flowing through the air introduction path with exhaust gas discharged from the incinerator, and a turbocharger disposed in the air introduction path, the turbocharger including a compressor for compressing the combustion air and discharging the compressed combustion air to the air preheater side, and a turbine for driving the compressor by rotating with the combustion air heated by the air preheater. A cooling device disposed in the air introduction path between the turbine and the incinerator for cooling the combustion air flowing out from the turbine, and a ventilating path connected to the air introduction path for discharging the combustion air flowing through the air introduction path to the outside of the air introduction path, the ventilating path being connected to a portion of the air introduction path downstream of the cooling device and upstream of the incinerator. In other words, the cooling device is disposed on the turbine side of the air introduction path relative to the connection portion of the air discharge path.

[0008] According to this waste treatment facility, the high-temperature combustion air heated by the air preheater is introduced into the turbine, and the combustion air cooled by the cooling device after flowing out from the turbine can be introduced into the incinerator. As a result, even if the temperature of the combustion air required to prevent the temperature inside the furnace from exceeding the heat-resistant temperature of the incinerator is lower than the temperature of the combustion air required to maintain the independent operation of the turbocharger, it is possible to deal with this by lowering the temperature of the combustion air after flowing out from the turbine. Therefore, according to the waste treatment facility of the present invention, it is possible to suppress an excessive rise in temperature inside the incinerator while maintaining the independent operation of the turbocharger. Moreover, compared to the case where the cooling device is disposed on the incinerator side of the connection part of the air discharge path in the air introduction path, the amount of heat recovered from the combustion air by the heat medium is increased, so that the efficiency of heat utilization can be improved. Moreover, since the combustion air after cooling can be discharged outside the air introduction path, it is also possible to reduce the diameter of the pipes and ducts constituting the air discharge path.

[0009] A waste treatment facility according to another aspect of the present invention includes an incinerator for incinerating waste, an air introduction path for introducing combustion air to the incinerator, an air preheater for heating the combustion air flowing through the air introduction path with exhaust gas discharged from the incinerator, and a turbocharger disposed in the air introduction path, the turbocharger including a compressor for compressing the combustion air and discharging the compressed combustion air to the air preheater side, and a turbine for driving the compressor by being rotated by the combustion air heated by the air preheater; and a turbocharger disposed in the air introduction path between the turbine and the incinerator. the combustion air flowing out of the turbine, the combustion air flowing out of the turbine being cooled by a cooling device disposed in the air introduction path, a bypass path connected to the air introduction path so as to bypass the cooling device, an air inflow rate adjustment unit adjusting a ratio between an inflow rate of the combustion air from the air introduction path to the bypass path and an inflow rate of the combustion air from the air introduction path to the cooling device, and a ventilating path for discharging the combustion air flowing through the air introduction path to the outside of the air introduction path, the ventilating path being connected to a portion of the air introduction path downstream of the cooling device and upstream of a connection portion of the downstream end of the bypass path.

[0010] According to this configuration, the combustion air cooled by the cooling device can be discharged outside the air introduction path before being mixed with the high-temperature combustion air flowing through the bypass path, which allows the diameter of the pipes and ducts that make up the air discharge path to be smaller than when the combustion air is discharged after being mixed with the high-temperature combustion air flowing through the bypass path.

[0011] A waste treatment facility according to another aspect of the present invention includes an incinerator for incinerating waste, an air introduction path for introducing combustion air to the incinerator, an air preheater for heating the combustion air flowing through the air introduction path with exhaust gas discharged from the incinerator, and a turbocharger arranged in the air introduction path, the turbocharger including a compressor for compressing the combustion air and discharging the compressed combustion air to the air preheater side, and a turbine for driving the compressor by rotating with the combustion air heated by the air preheater. A cooling device arranged in the air introduction path between the turbine and the incinerator for cooling the combustion air flowing out from the turbine, and a ventilating path connected to the air introduction path for discharging the combustion air flowing through the air introduction path to the outside of the air introduction path, the ventilating path being connected to a portion of the air introduction path upstream of the cooling device and downstream of the turbine. In other words, the cooling device is disposed on the incinerator side of the air introduction path relative to the connection part of the air discharge path.

[0012] With this configuration, the amount of combustion air flowing into the cooling device can be reduced compared to when the cooling device is located on the turbine side of the connection part of the air introduction path to the blowing path, which makes it possible to further reduce the load on the cooling device.

[0013] In the above waste treatment facility, the incinerator may be a fluidized bed incinerator, and may further include a freeboard temperature detection unit that detects the temperature of a freeboard in the incinerator, and a control unit that controls the air inflow adjustment unit so that the temperature detected by the freeboard temperature detection unit approaches a target temperature.

[0014] In the waste treatment facility, the incinerator may be a fluidized bed incinerator. The waste treatment facility may further include a bypass path connected to the air introduction path so as to bypass the cooling device, a freeboard temperature detection unit that detects the temperature of the freeboard in the incinerator, an air inflow rate adjustment unit that adjusts the ratio between the inflow rate of the combustion air from the air introduction path to the bypass path and the inflow rate of the combustion air from the air introduction path to the cooling device, and a control unit that controls the air inflow rate adjustment unit so that the temperature detected by the freeboard temperature detection unit approaches its target temperature.

[0015] According to this configuration, by controlling the temperature of the freeboard to approach the target temperature using the bypass path and the air inflow adjustment unit, it is possible to efficiently suppress excessive temperature rise in the incinerator while maintaining independent operation of the turbocharger.

[0016] In the waste treatment facility, the incinerator may be a fluidized bed incinerator. The waste treatment facility may further include a heat medium inflow rate adjustment unit that adjusts the inflow rate of the heat medium supplied to the cooling device, a freeboard temperature detection unit that detects the temperature of a freeboard in the incinerator, and a control unit that controls the heat medium inflow rate adjustment unit so that the temperature detected by the freeboard temperature detection unit approaches a target temperature.

[0017] According to this configuration, by controlling the freeboard temperature to approach its target temperature by adjusting the inflow rate of the heat transfer medium supplied to the cooling device, it is possible to efficiently suppress excessive heating in the incinerator while maintaining independent operation of the turbocharger.

[0018] The waste treatment facility may further include an inlet temperature detector that detects the temperature of the combustion air flowing through the air introduction path between the cooling device and the incinerator. The control unit may control the air inflow adjustment unit so that the temperature detected by the inlet temperature detector approaches the target temperature. The target temperature of the inlet temperature detector may be a temperature calculated based on the target temperature of the freeboard temperature detector and the properties of the waste.

[0019] The waste treatment facility may further include an inlet temperature detector that detects the temperature of the combustion air flowing through the air introduction path between the cooling device and the incinerator. The control unit may control the heat medium inflow rate regulator so that the temperature detected by the inlet temperature detector approaches the target temperature. The target temperature of the inlet temperature detector may be a temperature calculated based on the target temperature of the freeboard temperature detector and the properties of the waste.

[0020] According to this configuration, by using the furnace inlet temperature as the control index for the air inflow rate adjustment unit or the heat medium inflow rate adjustment unit, the stability of temperature control can be improved compared to when the freeboard temperature is used as the control index.

[0021] The waste treatment facility may further include a fluidized bed temperature detector that detects the temperature of the fluidized bed in the incinerator. The control unit may control the air inflow adjustment unit so that the temperature detected by the fluidized bed temperature detector approaches the target temperature. The target temperature of the fluidized bed temperature detector may be set based on the target temperature of the freeboard temperature detector and the correlation between the temperature of the freeboard and the temperature of the fluidized bed in the incinerator.

[0022] The waste treatment facility may further include a fluidized bed temperature detector that detects the temperature of the fluidized bed in the incinerator. The control unit may control the heat medium inflow rate regulator so that the temperature detected by the fluidized bed temperature detector approaches the target temperature. The target temperature of the fluidized bed temperature detector may be set based on the target temperature of the freeboard temperature detector and the correlation between the temperature of the freeboard and the temperature of the fluidized bed in the incinerator.

[0023] According to this configuration, by using the temperature of the fluidized bed as the control index for the air inflow rate adjustment section or the heat medium inflow rate adjustment section, the stability of temperature control can be improved compared to the case where the temperature of the freeboard is used as the control index.

[0024] In the above waste treatment facility, the cooling device may be configured with a heat exchanger that exchanges heat between the combustion air flowing out of the turbine and a heat medium supplied to a heat utilization facility.

[0025] According to this configuration, the heat recovered from the combustion air when the combustion air is cooled can be effectively utilized in other equipment.

[0026] The waste treatment equipment may further include a sprinkler unit for sprinkling water inside the incinerator, and the control unit may be configured to be able to simultaneously control the sprinkler unit when controlling the air inflow adjustment unit to bring the temperature detected by the freeboard temperature detection unit closer to the target temperature.

[0027] The waste treatment facility may further include a sprinkler unit for sprinkling water inside the incinerator, and the control unit may be configured to be able to simultaneously control the sprinkler unit when controlling the heat medium inflow rate adjustment unit to bring the temperature detected by the freeboard temperature detection unit closer to the target temperature. Effect of the Invention

[0028] As is clear from the above description, according to the present invention, it is possible to provide a waste treatment facility that is capable of suppressing an excessive rise in temperature inside an incinerator while maintaining the autonomous operation of a turbocharger. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a waste treatment facility according to a first embodiment of the present invention. [Diagram 2] 3 is a block diagram showing a configuration of a control unit in the waste treatment facility. FIG. [Diagram 3] 5 is a flowchart for explaining damper opening control in the waste treatment facility. [Figure 4] FIG. 4 is a diagram showing a schematic configuration of a waste treatment facility according to a second embodiment of the present invention. [Diagram 5] FIG. 11 is a diagram showing a schematic configuration of a waste treatment facility according to a third embodiment of the present invention. [Figure 6] FIG. 11 is a block diagram showing the configuration of a control unit in a waste treatment facility according to a third embodiment of the present invention. [Figure 7] 10 is a flowchart for explaining valve opening control in a waste treatment facility according to a third embodiment of the present invention. [Figure 8] FIG. 11 is a diagram showing a schematic configuration of a waste treatment facility according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A waste treatment facility according to an embodiment of the present invention will be described in detail below with reference to the drawings.

[0031] (Embodiment 1) First, the configuration of a waste treatment facility 1 according to a first embodiment of the present invention will be described with reference to Fig. 1 and Fig. 2. The waste treatment facility 1 according to this embodiment is a facility for incinerating waste such as sewage sludge. As shown in Fig. 1, the waste treatment facility 1 mainly includes an incinerator 10, an air introduction path 40, an air preheater 30, a turbocharger 50 including a compressor 51 and a turbine 52, a cooling device 80, a bypass path 83, an air inflow adjustment unit 90, and an air discharge path 64.

[0032] The incinerator 10 incinerates waste such as sewage sludge, and is, for example, a fluidized bed incinerator. As shown in Fig. 1, a fluidized bed 16 filled with a fluidizing medium such as sand is formed in the lower part of the incinerator 10, and the space above the fluidized bed 16 is the freeboard FB.

[0033] An exhaust gas outlet 10A is formed in the upper part of the incinerator 10. The air introduction path 40 is a path for guiding the combustion air A1 to the incinerator 10. The air introduction path 40 has first to fourth paths 41 to 44, and the combustion air A1 is introduced into the incinerator 10 by flowing through the first to fourth paths 41 to 44 in order.

[0034] The first path 41 has an intake port (not shown) for the combustion air A1 at its upstream end, and its downstream end is connected to the intake port of the compressor 51. The second path 42 has an upstream end connected to the discharge port of the compressor 51, and its downstream end is connected to the inlet of the air preheater 30. The third path 43 has an upstream end connected to the outlet of the air preheater 30, and its downstream end is connected to the intake port of the turbine 52. The fourth path 44 has an upstream end connected to the discharge port of the turbine 52, and its downstream end is connected to the combustion air inlet 10B of the incinerator 10.

[0035] The air preheater 30 heats the combustion air A1 flowing through the air introduction path 40 with the exhaust gas G1 discharged from the incinerator 10. The air preheater 30 is composed of a heat exchanger, and exchanges heat between the exhaust gas G1 introduced from the exhaust gas path 20 and the combustion air A1 introduced from the second path 42.

[0036] The turbocharger 50 is disposed in the air introduction path 40, and has a compressor 51 disposed in the air introduction path 40 on the upstream side of the air preheater 30, and a turbine 52 disposed in the air introduction path 40 on the downstream side of the air preheater 30. The compressor 51 and the turbine 52 are connected to each other by a rotating shaft 53. The "upstream side" and the "downstream side" in the air introduction path 40 are based on the direction in which the combustion air A1 flows toward the incinerator 10.

[0037] The compressor 51 compresses the combustion air A1 sucked in from the first passage 41 and discharges the compressed combustion air A1 to the air preheater 30. The turbine 52 drives the compressor 51 by being rotated by the combustion air A1 heated by the air preheater 30. That is, the rotation of the turbine 52 is transmitted to the compressor 51 via the rotating shaft 53, thereby driving the compressor 51. In this embodiment, as an example, the combustion air A1 of about 500 to 650°C flows into the turbine 52, and the combustion air A1 of about 400 to 550°C flows out from the turbine 52, but is not limited thereto.

[0038] The cooling device 80 cools the combustion air A1 flowing out from the turbine 52, and is disposed between the turbine 52 and the incinerator 10 (fourth path 44) in the air introduction path 40. The cooling device 80 in this embodiment is configured by a heat exchanger, and has a high-temperature side flow path 81 through which the combustion air A1 flowing out from the turbine 52 flows, and a low-temperature side flow path 82 through which a heat medium H1 (a medium having a lower temperature than the combustion air A1 flowing out from the turbine 52), such as cooling water or cooling air, flows. The cooling device 80 cools the combustion air A1 by performing heat exchange between the combustion air A1 flowing through the high-temperature side flow path 81 and the heat medium H1 flowing through the low-temperature side flow path 82. In this embodiment, the heat medium H1 may be supplied to a heat utilization facility such as a binary power generation device after heat recovery from the combustion air A1.

[0039] The bypass path 83 is connected to the air introduction path 40 so as to bypass the cooling device 80. As shown in Fig. 1, the bypass path 83 has an upstream end 83A connected to a portion of the fourth path 44 between the turbine 52 and the cooling device 80, and a downstream end 83B connected to a portion of the fourth path 44 between the cooling device 80 and the incinerator 10.

[0040] The air inflow rate adjustment unit 90 adjusts the ratio between the inflow rate of the combustion air A1 from the fourth path 44 to the bypass path 83 and the inflow rate of the combustion air A1 from the fourth path 44 to the cooling device 80 (high temperature side flow path 81).

[0041] 1, the cooling inlet damper 91 is disposed in a portion of the fourth path 44 between the upstream end 83A of the bypass path 83 and the cooling device 80, and the bypass damper 93 is disposed in the bypass path 83. In addition, a cooling outlet damper 92 is disposed in a portion of the fourth path 44 between the cooling device 80 and the downstream end 83B of the bypass path 83. Either the cooling inlet damper 91 or the cooling outlet damper 92, and the bypass damper 93 are each configured to have an adjustable opening degree.

[0042] The air discharge path 64 is a path for discharging the combustion air A1 flowing through the air introduction path 40 to the outside of the air introduction path 40. As shown in FIG. 1, in this embodiment, one end of the air discharge path 64 is connected to a portion of the fourth path 44 downstream of the connection part of the downstream end 83B of the bypass path 83, and the other end of the air discharge path 64 is opened to the outside air. That is, the cooling device 80 in this embodiment is disposed on the turbine 52 side (upstream side) of the connection part of the fourth path 44 to the air discharge path 64. A discharge valve V1 is disposed in the air discharge path 64, and by opening the discharge valve V1, the combustion air A1 flowing out from the cooling device 80 (high temperature side flow path 81) is discharged to the outside air through the air discharge path 64.

[0043] The waste treatment facility 1 further includes a freeboard temperature detector 11, a fluidized bed temperature detector 12, and a furnace inlet temperature detector 13. The freeboard temperature detector 11 is a sensor that detects the temperature of the freeboard FB in the incinerator 10, and outputs a signal according to the detected temperature. The freeboard temperature detector 11 is provided on the side of the incinerator 10, above the fluidized bed 16.

[0044] The fluidized bed temperature detection unit 12 is a sensor that detects the temperature of the fluidized bed 16 in the incinerator 10, and outputs a signal according to the detected temperature. The inlet temperature detection unit 13 is a sensor that detects the temperature of the combustion air A1 flowing between the cooling device 80 and the incinerator 10 in the fourth path 44, and outputs a signal according to the detected temperature. As shown in FIG. 1, the inlet temperature detection unit 13 in this embodiment is disposed in a portion of the fourth path 44 between the connection portion of the vent path 64 and the incinerator 10. However, the position of the inlet temperature detection unit 13 is not limited thereto, and the inlet temperature detection unit 13 may be disposed, for example, in a wind box (not shown) below the fluidized bed 16 in the incinerator 10.

[0045] The waste treatment facility 1 further includes a control unit 100 (FIG. 2) that controls the air inflow adjustment unit 90 so that the temperature detected by the freeboard temperature detection unit 11 approaches a target temperature. FIG. 2 is a block diagram showing each function of the control unit 100. As shown in FIG. 2, the control unit 100 includes a receiving unit 101, a determining unit 102, an opening control unit 103, and a calculating unit 104.

[0046] The reception unit 101 receives detection signals from the freeboard temperature detection unit 11, the fluidized bed temperature detection unit 12, and the inlet temperature detection unit 13. The judgment unit 102 compares the detection data input to the reception unit 101 with the target temperature and judges whether the data is larger or smaller. The opening control unit 103 controls the opening of either the cooling inlet damper 91 or the cooling outlet damper 92 and the bypass damper 93 based on the judgment result by the judgment unit 102. The calculation unit 104 calculates the target temperature of the inlet temperature detection unit 13 based on the target temperature of the freeboard temperature detection unit 11 and the properties of the waste to be fed into the incinerator 10 (for example, the moisture content of sewage sludge). The reception unit 101, the judgment unit 102, the opening control unit 103, and the calculation unit 104 are functions executed by the central processing unit of the computer constituting the control unit 100.

[0047] In this embodiment, the control unit 100 controls the air inflow adjustment unit 90 so that the temperature detected by the furnace inlet temperature detection unit 13 approaches the target temperature. That is, by controlling the temperature detected by the furnace inlet temperature detection unit 13 to approach the target temperature, the temperature detected by the freeboard temperature detection unit 11 approaches the target temperature. This control will be described below with reference to the flowchart in FIG.

[0048] First, a target temperature of the inlet temperature detector 13 is set (step S10). Specifically, based on the target temperature of the freeboard temperature detector 11 and the properties of the waste fed into the incinerator 10 (e.g., the moisture content of sewage sludge, etc.), a target temperature of the inlet temperature detector 13 required to make the temperature detected by the freeboard temperature detector 11 the target temperature is calculated and set by heat balance calculation. This calculation and setting may be performed by the calculation unit 104, or the target temperature may be set manually as appropriate according to the actual operating state.

[0049] In this embodiment, the target temperature of the freeboard temperature detection unit 11 is set to, for example, 850 to 880°C, and based on this and the moisture content of the sewage sludge, the target temperature of the furnace inlet temperature detection unit 13 is set to, for example, 300°C.

[0050] Next, during normal operation of the waste treatment facility 1, that is, while the combustion air A1 passes through the compressor 51, the air preheater 30, and the turbine 52 in order and is introduced into the incinerator 10, the temperature of the combustion air A1 is detected by the inlet temperature detection unit 13 (step S20), and the detection signal is input to the reception unit 101. Then, the determination unit 102 determines whether or not the detected temperature exceeds the target temperature set in the above step S10 (step S30).

[0051] Then, when it is determined that the detected temperature exceeds the target temperature (YES in step S30), the opening control unit 103 increases the opening of the cooling inlet damper 91 and decreases the opening of the bypass damper 93 (step S40). This increases the amount of combustion air A1 flowing into the cooling device 80 and decreases the amount of combustion air A1 flowing into the bypass path 83. Note that the opening control unit 103 may increase only the opening of the cooling inlet damper 91 without changing the opening of the bypass damper 93, or may decrease only the opening of the bypass damper 93 without changing the opening of the cooling inlet damper 91.

[0052] Next, after changing the opening degree of the cooling inlet damper 91 and the bypass damper 93, or when the temperature detected by the furnace inlet temperature detection unit 13 does not exceed the target temperature (NO in step S30), the judgment unit 102 judges whether the temperature detected by the furnace inlet temperature detection unit 13 is less than the target temperature (step S50). If the detected temperature is less than the target temperature (YES in step S50), the opening degree control unit 103 decreases the opening degree of the cooling inlet damper 91 and increases the opening degree of the bypass damper 93 (step S60). As a result, the inflow amount of the combustion air A1 into the cooling device 80 decreases, and the inflow amount of the combustion air A1 into the bypass path 83 increases. The opening degree control unit 103 may decrease only the opening degree of the cooling inlet damper 91 without changing the opening degree of the bypass damper 93, or may increase only the opening degree of the bypass damper 93 without changing the opening degree of the cooling inlet damper 91.

[0053] After the opening degree of the cooling inlet damper 91 and the bypass damper 93 is changed, or if the temperature detected by the furnace inlet temperature detection unit 13 is not below the target temperature (NO in step S50), the process proceeds to step S70, where it is determined whether or not the end condition of the control is satisfied. If the end condition is satisfied (YES in step S70), the control is terminated, and if the end condition is not satisfied (NO in step S70), the process returns to step S20 to continue the damper opening control.

[0054] As described above, according to the waste treatment facility 1 of this embodiment, the combustion air A1 at a high temperature (about 500 to 700 ° C.) heated by the air preheater 30 is introduced into the turbine 52, and the combustion air A1 cooled by the cooling device 80 after flowing out of the turbine 52 can be introduced into the incinerator 10. As a result, even if the temperature of the combustion air A1 required to prevent the temperature inside the incinerator 10 from exceeding the heat resistance temperature of the incinerator 10 or the heat exchanger (air preheater 30) located in the rear stage of the incinerator 10 is lower than the temperature of the combustion air A1 required to maintain the independent operation of the turbocharger 50, it is possible to deal with this by lowering the temperature of the combustion air A1 after flowing out of the turbine 52. Therefore, according to the waste treatment facility 1 of this embodiment, it is possible to suppress the excessive temperature rise inside the incinerator 10 while maintaining the independent operation of the turbocharger 50.

[0055] In this embodiment, the temperature detected by the freeboard temperature detection unit 11 is not used as the control index of the air inflow adjustment unit 90, but the temperature detected by the furnace inlet temperature detection unit 13 is used as the control index. However, the target temperature of the furnace inlet temperature detection unit 13 may be changed during the control of FIG. 3. Specifically, the freeboard temperature detection unit 11 continues to detect the temperature during the steady operation of the waste treatment facility 1, and if the temperature detected by the freeboard temperature detection unit 11 is higher than the target temperature even though the temperature detected by the furnace inlet temperature detection unit 13 is the target temperature, the target temperature of the furnace inlet temperature detection unit 13 may be lowered. Also, if the temperature detected by the freeboard temperature detection unit 11 is lower than the target temperature even though the temperature detected by the furnace inlet temperature detection unit 13 is the target temperature, the target temperature of the furnace inlet temperature detection unit 13 may be raised.

[0056] (Embodiment 2) Next, a waste treatment facility 1A according to a second embodiment of the present invention will be described with reference to Fig. 4. The waste treatment facility 1A according to the second embodiment basically has the same configuration as the waste treatment facility 1 according to the first embodiment and achieves the same effects, but differs from the first embodiment in the positional relationship between the cooling device 80 and the air discharge path 64. Only the differences from the first embodiment will be described below.

[0057] As shown in Fig. 4, the cooling device 80 in this embodiment is disposed on the incinerator 10 side (downstream side) of the connection part of the air introduction path 40 (fourth path 44) with the air discharge path 64. More specifically, one end of the air discharge path 64 is connected to the fourth path 44 downstream of the turbine 52 and upstream of the upstream end 83A of the bypass path 83, and the other end of the air discharge path 64 is open to the outside air. In the second embodiment, the heat medium H1 used for cooling the combustion air A1 may be sent to a heat utilization facility for heat utilization, or may be discarded without being sent to the heat utilization facility.

[0058] According to the waste treatment facility 1A of the second embodiment, the combustion air A1 flows out of the turbine 52 and is then partially released through the air discharge path 64, and then flows into the cooling device 80. Therefore, the amount of the combustion air A1 flowing into the cooling device 80 can be reduced compared to the first embodiment, in which the cooling device 80 is disposed on the turbine 52 side of the fourth path 44 relative to the connection portion of the air discharge path 64. This makes it possible to further reduce the load on the cooling device 80.

[0059] (Embodiment 3) Next, a waste treatment facility 1B according to a third embodiment of the present invention will be described with reference to Figures 5 to 7. The waste treatment facility 1B according to the third embodiment basically has the same configuration and produces the same effects as the waste treatment facility 1 according to the first embodiment, but differs from the first embodiment in that it includes a heat medium inflow rate adjuster 84 instead of the bypass path 83, the cooling inlet damper 91, the cooling outlet damper 92, and the bypass damper 93. Only the differences from the first embodiment will be described below.

[0060] The heat medium inflow rate adjustment unit 84 adjusts the inflow rate of the heat medium H1 supplied to the cooling device 80, and is configured with a valve with an adjustable opening (heat medium inlet valve). As shown in Fig. 5, the heat medium inflow rate adjustment unit 84 is disposed upstream of the cooling device 80 in the heat medium flow path 80A connected to the low-temperature side flow path 82 of the cooling device 80.

[0061] The control unit 100 controls the heat medium inflow rate adjustment unit 84 so that the temperature detected by the freeboard temperature detection unit 11 approaches the target temperature (FIGS. 6 and 7). FIG. 7 is a flowchart showing the opening control of the heat medium inflow rate adjustment unit 84 (heat medium inlet valve) by the control unit 100 (opening control unit 103). The control flow of FIG. 7 is similar to the control flow of FIG. 3, except that in step S40, the opening of the cooling inlet damper 91 is increased and the opening of the bypass damper 93 is decreased, instead of increasing the opening of the heat medium inlet valve (step S41), and in step S60, the opening of the cooling inlet damper 91 is decreased and the opening of the bypass damper 93 is increased, instead of decreasing the opening of the heat medium inlet valve (step S61).

[0062] (Embodiment 4) Next, a waste treatment facility 1C according to a fourth embodiment of the present invention will be described with reference to Fig. 8. The waste treatment facility 1C according to the fourth embodiment basically has the same configuration as the waste treatment facility 1 according to the first embodiment and achieves the same effects, but differs from the first embodiment in the connection position of the air discharge path 64. Only the differences from the first embodiment will be described below.

[0063] 8, the upstream end of the air discharge path 64 is connected to the air introduction path 40 (fourth path 44) downstream of the cooling device 80 and upstream of the connection part of the downstream end 83B of the bypass path 83. More specifically, the upstream end of the air discharge path 64 is connected to the fourth path 44 on the incinerator 10 side (downstream side) of the cooling outlet damper 92.

[0064] This allows the combustion air A1 cooled by the cooling device 80 to be discharged outside the fourth path 44 before being mixed with the high-temperature combustion air A1 (combustion air A1 not cooled by the cooling device 80) flowing through the bypass path 83. This allows the diameters of the pipes and ducts constituting the air discharge path 64 to be made smaller than in the case of discharging the combustion air A1 after being mixed with the high-temperature combustion air A1 flowing through the bypass path 83 as in the first embodiment.

[0065] (Other embodiments) Here, other embodiments of the present invention will be described.

[0066] In the above-mentioned first and third embodiments, the damper opening of the air inflow amount adjustment unit 90 or the valve opening of the heat medium inflow amount adjustment unit 84 is controlled based on the temperature detected by the furnace inlet temperature detection unit 13, but the present invention is not limited to this. In the above-mentioned first embodiment, the control unit 100 may control the air inflow amount adjustment unit 90 so that the temperature detected by the fluidized bed temperature detection unit 12 approaches the target temperature. In this case, the damper opening is controlled in the same manner as in the flowchart of FIG. 3, except that the fluidized bed temperature is used as the control index instead of the furnace inlet temperature. The target temperature of the fluidized bed temperature detection unit 12 is set based on the target temperature of the freeboard temperature detection unit 11 and the correlation between the temperature of the freeboard FB and the temperature of the fluidized bed 16 in the incinerator 10. This correlation is obtained from the past operation record of the waste treatment facility 1. The target temperature of the fluidized bed temperature detection unit 12 may be maintained at a value set based on the above correlation, or the target temperature of the fluidized bed temperature detection unit 12 may be appropriately changed based on the detected temperature of the freeboard FB.

[0067] In the third embodiment, the control unit 100 may control the heat medium inflow rate adjustment unit 84 so that the temperature detected by the fluidized bed temperature detection unit 12 approaches the target temperature. In this case, the valve opening is controlled in the same manner as in the flowchart of Fig. 7, except that the fluidized bed temperature is used as the control index instead of the furnace inlet temperature. Similarly to the above, the target temperature of the fluidized bed temperature detection unit 12 is set based on the target temperature of the freeboard temperature detection unit 11 and the correlation between the temperature of the freeboard FB and the temperature of the fluidized bed 16 in the incinerator 10.

[0068] In the first and third embodiments, the damper opening of the air inflow rate adjustment unit 90 or the valve opening of the heat medium inflow rate adjustment unit 84 may be controlled based on the temperature detected by the freeboard temperature detection unit 11. In these cases, the same control as in the flowcharts of Figures 3 and 7 is possible. In the third embodiment, the heat medium inflow rate adjustment unit 84 may be disposed downstream of the cooling device 80 in the heat medium flow path 80A connected to the low-temperature side flow path 82 of the cooling device 80.

[0069] In the waste treatment facility 1 of the above-mentioned embodiment 1, a water sprinkling section for sprinkling water inside the incinerator 10 (freeboard FB) and a water adding section for adding water inside the sludge injector may be further provided. These may be used as auxiliary means together with the cooling device 80 when it is difficult to control the temperature of the freeboard FB by the cooling device 80 alone.

[0070] In the above-described first embodiment, the opening degrees of the cooling inlet damper 91 and the bypass damper 93 are automatically controlled by the control unit 100. However, the opening degrees of the cooling inlet damper 91 and the bypass damper 93 may be manually controlled.

[0071] In the above embodiment 1, a fluidized bed incinerator has been described as an example of an incinerator, but the present invention can be applied to other incinerators. In addition, the type of waste is not limited to sewage sludge, and may be, for example, urban waste.

[0072] The embodiments disclosed herein are illustrative in all respects and should not be construed as limiting. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0073] 10 Incinerator 11 Freeboard temperature detector 12 Fluidized bed temperature detection unit 13 Furnace inlet temperature detector 30 Air preheater 40 Air intake path 50 Turbocharger 51 Compressor 52 Turbine 64 Wind Path 80 Cooling device 83 Bypass Route 84 Heat medium inflow adjustment section 90 Air inflow adjustment section 100 Control section A1 Combustion air FB Freeboard G1 Exhaust gas H1 heat medium

Claims

1. An incinerator for incinerating waste; An air introduction path for introducing combustion air into the incinerator; An air preheater that heats the combustion air flowing through the air introduction path with exhaust gas discharged from the incinerator; a turbocharger disposed in the air introduction path, the turbocharger including a compressor that compresses the combustion air and discharges the compressed combustion air to the air preheater side, and a turbine that drives the compressor by being rotated by the combustion air heated by the air preheater; A cooling device is disposed in the air introduction path between the turbine and the incinerator, and cools the combustion air flowing out from the turbine; a bypass path connected to the air introduction path so as to bypass the cooling device; an air inflow rate adjustment unit that adjusts a ratio between an inflow rate of the combustion air from the air introduction path to the bypass path and an inflow rate of the combustion air from the air introduction path to the cooling device; a ventilation path for discharging the combustion air flowing through the air introduction path to the outside of the air introduction path, The waste treatment facility, wherein the air discharge path is connected to a portion of the air introduction path that is downstream of the cooling device and upstream of a connection portion of the downstream end of the bypass path.

2. The incinerator is a fluidized bed incinerator, A freeboard temperature detection unit that detects the temperature of the freeboard in the incinerator; 2. The waste treatment facility according to claim 1, further comprising a control unit that controls the air inflow rate regulator so that the temperature detected by the freeboard temperature detector approaches a target temperature.

3. Further provided is an inlet temperature detection unit that detects the temperature of the combustion air flowing between the cooling device and the incinerator in the air introduction path; The control unit is configured to control the air inflow adjustment unit so that the temperature detected by the furnace inlet temperature detection unit approaches the target temperature, 3. The waste treatment facility according to claim 2, wherein the target temperature of the furnace inlet temperature detector is a temperature calculated based on the target temperature of the freeboard temperature detector and properties of the waste.

4. Further comprising a fluidized bed temperature detection unit for detecting the temperature of the fluidized bed in the incinerator; The control unit is configured to control the air inflow adjustment unit so that the temperature detected by the fluidized bed temperature detection unit approaches the target temperature, The waste treatment facility according to claim 2, wherein the target temperature of the fluidized bed temperature detection unit is set based on the target temperature of the freeboard temperature detection unit and a correlation between the temperature of the freeboard and the temperature of the fluidized bed in the incinerator.

5. 3. The waste treatment facility according to claim 1, wherein the cooling device is configured with a heat exchanger that exchanges heat between the combustion air flowing out of the turbine and a heat medium supplied to a heat utilization facility.

6. Further comprising a water sprinkler unit for sprinkling water inside the incinerator, The waste treatment facility according to claim 2, wherein the control unit is configured to control the water sprinkler unit when controlling the air inflow adjustment unit to bring the temperature detected by the freeboard temperature detection unit closer to the target temperature.

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