Incineration system and incineration method

Abstract

To provide an incineration system and an incineration method enabling suppression of a temperature rise in an incinerator.SOLUTION: An incineration system includes: a supercharger having a compressor and a turbine; a first heat exchanger that raises a temperature of compressed gas compressed by the compressor by using exhaust gas discharged from an incinerator and supplies the compressed gas of which temperature has been raised; and a second heat exchanger that cools the compressed gas of which temperature has been raised in the first heat exchanger by exchanging heat with fluid and supplies the cooled compressed gas to the turbine. The turbine supplies the compressed gas cooled by the second heat exchanger to the incinerator.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an incineration system and an incineration method. [Background technology]

[0002] In incinerators such as sewage sludge incinerators, the high-temperature exhaust gas discharged from the incinerator is passed through a heat exchanger to recover part of the exhaust heat, and then the dust is separated and removed in a dust collector. The exhaust gas is then passed through a flue gas treatment tower and washed with water to remove the SO in the exhaust gas. X Exhaust gas treatment is carried out to remove components such as sulfur dioxide and HCl (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-227441 Summary of the Invention [Problem to be solved by the invention]

[0004] In general, the incinerator is operated by maintaining the temperature inside the incinerator at a predetermined target temperature. If the temperature inside the incinerator exceeds the target temperature, for example, NOx is released during combustion. X This is because the ash is likely to be generated, and problems such as the ash melting and adhering to the furnace walls and piping occur.

[0005] Therefore, an object of the present invention is to provide an incineration system and an incineration method that suppress the temperature rise inside the incinerator. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the incineration system of the present invention comprises a turbocharger having a compressor and a turbine, a first heat exchanger that heats compressed gas compressed by the compressor using exhaust gas discharged from an incinerator and supplies the heated compressed gas, and a second heat exchanger that cools the compressed gas heated in the first heat exchanger by heat exchange with a fluid and supplies the cooled compressed gas to the turbine, and the turbine supplies the compressed gas cooled in the second heat exchanger to the incinerator. [Effects of the Invention]

[0007] According to the incineration system and incineration method of the present invention, it is possible to suppress the temperature rise inside the incinerator. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of an incineration system 100 according to the first embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of the configuration of an incineration system 200 according to the second embodiment. [Figure 3] FIG. 3 is a diagram illustrating an example of the configuration of an incineration system 300 according to the third embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of the configuration of an incineration system 400 according to the fourth embodiment. [Figure 5] FIG. 5 is a diagram illustrating an example of the configuration of an incineration system 500 according to the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. However, the technical scope of the present invention is not limited to these preferred embodiments.

[0010] [First embodiment] First, an incineration system 100 in the first embodiment will be described. Figure 1 is a diagram illustrating an example of the configuration of the incineration system 100 in the first embodiment. Note that the positions and numbers of lines (pipes) and pumps shown below are examples and are not limited to these.

[0011] 1, the incineration system 100 includes, for example, an incinerator 1, a turbocharger 2, a fluidized air preheater 3, an air cooler 4, a cooling tower 6, a dust collector 7, a flue gas treatment tower 8, and a chimney 9. Hereinafter, the fluidized air preheater 3 will also be referred to as the first heat exchanger 3, and the air cooler 4 will also be referred to as the second heat exchanger 4.

[0012] The incinerator 1 is a fluidized bed incinerator that incinerates sludge. The incinerator 1 has a so-called fluidized bed 1a. The sludge is also called dehydrated cake. The incinerator 1 will be described below as a fluidized bed incinerator.

[0013] In recent years, the moisture content of sludge has decreased due to improvements in the capacity of sludge dehydrators. Furthermore, by drying the dehydrated sludge to further reduce the moisture content of the sludge, the efficiency of sludge combustion in incinerator 1 is improved. Therefore, in incinerator 1, as the moisture content of the sludge decreases, the sludge tends to be burned more vigorously, and the temperature inside the furnace may become higher than the target temperature.

[0014] Therefore, in the incineration systems in each of the following embodiments (incineration systems 100, 200, 300, 400 and 500), an air cooler 4 is provided on the outlet side of the fluidized air preheater 3 to lower the temperature of the combustion air supplied to the incinerator 1, thereby suppressing the temperature rise inside the incinerator 1.

[0015] The turbocharger 2 has a compressor 2a and a turbine 2b connected via a rotary shaft 2c. Specifically, the compressor 2a compresses sucked air to generate compressed gas and supplies the generated compressed gas to the fluidized air preheater 3. In addition, the turbine 2b uses the energy of the compressed gas supplied from the fluidized air preheater 3 via an air cooler 4 to rotate the rotary shaft 2c.

[0016] Here, the compressor 2a is driven in accordance with the rotation of the rotary shaft 2c by the turbine 2b, thereby compressing the sucked air to generate compressed gas, and the generated compressed gas is supplied to the fluidized air preheater 3.

[0017] The fluidized air preheater 3 exchanges heat between the exhaust gas discharged from the incinerator 1 and the compressed gas supplied from the compressor 2a via line L11. Specifically, the fluidized air preheater 3 uses the exhaust gas discharged from the incinerator 1 to heat the compressed gas compressed by the compressor 2a, and supplies the heated compressed gas to the air cooler 4 via line L12. The fluidized air preheater 3 also cools the exhaust gas discharged from the incinerator 1 and supplies the cooled exhaust gas to the cooling tower 6.

[0018] The air cooler 4 exchanges heat between the compressed gas supplied from the fluidizing air preheater 3 via line L12 and a fluid supplied from a fluid supply destination (not shown). Specifically, the air cooler 4 uses the compressed gas supplied from the fluidizing air preheater 3 to heat the fluid and supplies the heated fluid to the supply destination. The air cooler 4 also cools the compressed gas supplied from the fluidizing air preheater 3 and supplies the cooled compressed gas to the turbine 2b via line L13. The turbine 2b then rotates the rotary shaft 2c using the energy of the compressed gas supplied from the air cooler 4 via line L13, and supplies the compressed gas after the energy has been used to the incinerator 1.

[0019] When the cooled compressed gas is supplied to the fluidized bed 1a of the incinerator 1, the compressed gas is used as air for fluidizing the fluidized bed 1a and combusting the sludge. The cooled compressed gas may also be supplied to the so-called freeboard above the fluidized bed 1a. When the cooled compressed gas is supplied to the freeboard, the compressed gas is used as combustion air.

[0020] Cooling tower 6 is disposed downstream of fluidized air preheater 3, and cools the exhaust gas supplied from fluidized air preheater 3 by bringing the exhaust gas into contact with water sprayed from spray nozzles (not shown) provided inside cooling tower 6. Cooling tower 6 then supplies the cooled exhaust gas to dust collector 7.

[0021] The dust collector 7 is disposed downstream of the cooling tower 6 and removes impurities from the exhaust gas supplied from the cooling tower 6. The dust collector 7 may be, for example, a ceramic dust collector with excellent heat resistance.

[0022] The flue gas treatment tower 8 is disposed after the dust collector 7, and the flue gas is introduced into the tower from, for example, the bottom. The flue gas treatment tower 8 then brings the flue gas into contact with water sprayed from a water spray nozzle (not shown) at the top, thereby removing SO 2 in the flue gas. X Components such as sulfur dioxide and HCl are removed by soaking them in water. A chimney 9 is disposed above the flue gas treatment tower 8, and discharges the flue gas cleaned in the flue gas treatment tower 8 into the atmosphere.

[0023] The inducer P1 is a fan or blower that induces the exhaust gas discharged from the incinerator 1 to the exhaust gas treatment tower 8, and sends the cleaned exhaust gas in the exhaust gas treatment tower 8 to the chimney 9.

[0024] Thus, in the incineration system 100 of the first embodiment, the air cooler 4 is provided between the outlet side of the fluidized air preheater 3 and the inlet side of the turbine 2b. The compressed gas cooled in the air cooler 4 is supplied to the incinerator 1 via the turbine 2b.

[0025] That is, the incineration system 100 in the first embodiment includes a turbocharger 2 having a compressor 2a and a turbine 2b connected via a rotary shaft 2c, a fluidized air preheater 3 that heats the compressed gas compressed by the compressor 2a using exhaust gas discharged from the incinerator 1 and supplies the heated compressed gas to an air cooler 4, and an air cooler 4 that cools the compressed gas supplied from the fluidized air preheater 3 with a fluid and supplies the cooled compressed gas to the turbine 2b. The turbine 2b then supplies the compressed gas supplied from the air cooler 4 to the incinerator 1.

[0026] In the incineration system 100 of the first embodiment, the high-temperature compressed gas supplied from the fluidized air preheater 3 is not directly supplied to the turbine 2b, but this high-temperature compressed gas is air-cooled, so it is possible to suppress the temperature rise in the incinerator 1. Therefore, in the incineration system 100, NO X Furthermore, the incineration system 100 can prevent damage to refractories due to temperature increases, and can prevent blockage of pipes and the like due to adhesion of molten incineration ash, for example.

[0027] [Second embodiment] Next, an incineration system 200 in a second embodiment will be described. Figure 2 is a diagram illustrating an example of the configuration of the incineration system 200 in the second embodiment. Below, configurations that differ from the incineration system 100 described in Figure 1 will be described.

[0028] The incineration system 200 in the second embodiment has a power generation system 10 in addition to the incineration system 100 described in FIG.

[0029] The power generation system 10 has the function of recovering the thermal energy of the fluid circulating between the air cooler 4 and the power generation system 10 and converting it into other energy, and forms a thermal cycle such as a Rankine cycle or a Kalina cycle that circulates a low-boiling-point medium such as low-boiling-point chlorofluorocarbons, alternative chlorofluorocarbons, silicone oil, petroleum-based organic compounds, ammonia, or a mixed fluid of ammonia and water as the working medium.

[0030] The air cooler 4 exchanges heat between the compressed gas supplied from the fluidizing air preheater 3 via line L12 and a fluid supplied from the power generation system 10 via line L21. Specifically, the air cooler 4 uses the compressed gas supplied from the fluidizing air preheater 3 to heat the fluid, and supplies the heated fluid to the power generation system 10 via line L22. The air cooler 4 also cools the compressed gas supplied from the fluidizing air preheater 3, and supplies the cooled compressed gas to the turbine 2b via line L13.

[0031] That is, in the incineration system 200 in the second embodiment, the thermal energy recovered in the air cooler 4 is supplied to the power generation system 10.

[0032] This enables the power generation system 10 to generate power by using the thermal energy recovered in the air cooler 4.

[0033] The fluid flowing through the lines L21 and L22 may be, for example, heat transfer oil, or may be other liquids or gases such as water (steam) or air.

[0034] The fluid flowing through the line L21 and the line L22 is circulated between the air cooler 4 and the power generation system 10 by the pump P2, which is a circulation pump.

[0035] [Third embodiment] Next, an incineration system 300 in a third embodiment will be described. Figure 3 is a diagram illustrating an example of the configuration of the incineration system 300 in the third embodiment. Below, configurations that differ from the incineration system 200 described in Figure 2 will be described.

[0036] In the incineration system 300 of the third embodiment, the air cooler 4 and the dryer 20 are connected via a line L21 and a line L22.

[0037] The dryer 20 dries the sludge, for example, before it is incinerated in the incinerator 1. Specifically, the dryer 20 dries the sludge, for example, by using thermal energy recovered in the air cooler 4.

[0038] This allows the dryer 20 to dry sludge, for example, by utilizing the heat contained in the exhaust gas. That is, in the incineration system 300, by connecting the air cooler 4 to equipment other than the power generation system 10, it becomes possible to utilize the heat contained in the exhaust gas for purposes other than power generation.

[0039] [Fourth embodiment] Next, an incineration system 400 in a fourth embodiment will be described. Figure 4 is a diagram illustrating an example of the configuration of the incineration system 400 in the fourth embodiment. Below, configurations that differ from the incineration system 200 described in Figure 2 will be described.

[0040] As shown in Figure 4, the incineration system 400 includes, for example, a heat medium heater 5 in addition to the incineration system 100 described in Figure 1. The heat medium heater 5 will also be referred to as the third heat exchanger 5 hereinafter.

[0041] The fluidized air preheater 3 and the heat transfer medium heater 5 are connected in parallel, so to speak, and the exhaust gas discharged from the incinerator 1 is branched into two by a line, with a portion of the exhaust gas being supplied to the fluidized air preheater 3 and the other portion being supplied to the heat transfer medium heater 5.

[0042] The fluid discharged from the pump P2 (in other words, the fluid supplied from the power generation system 10) is supplied to the heat transfer medium heater 5 via a line L23, heated by the heat transfer medium heater 5, and supplied to the power generation system 10 via a line L24 that joins with the line L22. The fluid discharged from the pump P2 is also supplied to the air cooler 4 via a line L21, heated by the air cooler 4, and supplied to the power generation system 10 via the line L22.

[0043] The heat transfer medium heater 5 exchanges heat between the exhaust gas discharged from the incinerator 1 and a fluid supplied from the power generation system 10 via line L23. Specifically, the heat transfer medium heater 5 uses the exhaust gas discharged from the incinerator 1 to heat the fluid, and supplies the heated fluid to the power generation system 10 via line L24. The heat transfer medium heater 5 also cools the exhaust gas discharged from the incinerator 1, and supplies the cooled exhaust gas to the cooling tower 6.

[0044] The fluid flowing through the lines L23 and L24 may be, for example, heat transfer oil, or other liquids or gases such as water (steam) or air, similar to the fluid flowing through the lines L21 and L22.

[0045] Furthermore, the line L21 and the line L23 may merge near the power generation system 10, as shown in Fig. 4, or each may consist of two independent lines. Similarly, the line L22 and the line L24 may merge near the power generation system 10, as shown in Fig. 4, or each may consist of two independent lines.

[0046] That is, in the incineration system 400 in the fourth embodiment, the thermal energy recovered in the air cooler 4 and the thermal energy recovered in the heat medium heater 5 are each supplied to the power generation system 10.

[0047] This enables the power generation system 10 to generate power by using the thermal energy recovered in the air cooler 4 and the thermal energy recovered in the heat medium heater 5. Therefore, the power generation system 10 can generate power more efficiently by utilizing the heat contained in the exhaust gas discharged from the incinerator 1.

[0048] 4, lines L21 and L22 through which a fluid circulates between the air cooler 4 and the power generation system 10, and lines L23 and L24 through which a fluid circulates between the heat transfer medium heater 5 and the power generation system 10 are provided in parallel. That is, in the example shown in FIG. 4, a portion of the fluid from the power generation system 10 is supplied to the air cooler 4 via the line L22, and another portion is supplied to the heat transfer medium heater 5 via the line L23.

[0049] As a result, the incineration system 400 has a lower discharge rate than the incineration system 500 described later. It becomes possible to use a circulation pump (pump P2) with a small output pressure. Furthermore, in the incineration system 400, it becomes possible to make the transfer surface area of ​​the heat medium heater 5 smaller than in the case of the incineration system 500 described below.

[0050] 4, a valve V1 is provided in a line between the fluidized air preheater 3 and the cooling tower 6, and a valve V2 is provided in a line between the heat transfer medium heater 5 and the cooling tower 6. Furthermore, in the example shown in FIG. 4, a valve V3 (valve V3a and valve V3b) is provided in a line L21 between the air cooler 4 and the power generation system 10.

[0051] As a result, in the incineration system 400, for example, by adjusting the flow rate using valves V1, V2, and V3, it becomes possible to adjust the amount of thermal energy supplied to the power generation system 10. Specifically, for example, when the temperature of the incinerator 1 exceeds a threshold, the control device (not shown) decreases the aperture of valve V3b and increases the aperture of valve V3a in order to increase the proportion of fluid supplied to the air cooler 4 and recover more heat from the compressed gas from the turbine 2b. Furthermore, when the temperature of the incinerator 1 falls below the threshold, the control device (not shown) increases the aperture of valve V3b and decreases the aperture of valve V3a.

[0052] 4, the fluidized air preheater 3 and the heat transfer medium heater 5 are arranged in parallel, but the fluidized air preheater 3 and the heat transfer medium heater 5 may also be arranged directly. Specifically, in the example shown in FIG. 4, a portion of the exhaust gas discharged from the incinerator 1 is supplied to the fluidized air preheater 3, and another portion is supplied to the heat transfer medium heater 5. Alternatively, all of the exhaust gas discharged from the incinerator 1 may be supplied to the fluidized air preheater 3, and all of the exhaust gas that has passed through the fluidized air preheater 3 may be supplied to the heat transfer medium heater 5. Alternatively, all of the exhaust gas discharged from the incinerator 1 may be supplied to the heat transfer medium heater 5, and all of the exhaust gas that has passed through the heat transfer medium heater 5 may be supplied to the fluidized air preheater 3.

[0053] [Fifth embodiment] Next, an incineration system 500 in a fifth embodiment will be described. Figure 5 is a diagram illustrating an example of the configuration of the incineration system 500 in the fifth embodiment. Below, configurations that differ from the incineration system 400 described in Figure 4 will be described.

[0054] 4, the incineration system 500 in the fifth embodiment is different from the case described in Fig. 4 in that, instead of lines L21, L22, L23, and L24, lines L25, L26, and L27 are provided which connect the air cooler 4, the heat transfer medium heater 5, and the power generation system 10 in series. That is, in the example shown in Fig. 5, after a fluid is supplied from the power generation system 10 to the air cooler 4, the fluid is supplied from the air cooler 4 to the heat transfer medium heater 5. Then, in the example shown in Fig. 5, a fluid is further supplied from the heat transfer medium heater 5 to the power generation system 10.

[0055] This makes it easier in the incineration system 500 to control the temperature of the fluid supplied to the power generation system 10 than in the incineration system 400 described with reference to FIG. 4, for example.

[0056] In the example shown in FIG. 5, a bypass L28 is provided in the line L25 and the line L26, connecting before and after the position where the air cooler 4 is provided.

[0057] As a result, in the incineration system 500, for example, by adjusting the valve V4 (valve V4a and valve V4b) provided in the bypass L28, it becomes possible to adjust the amount of fluid supplied to the air cooler 4. Specifically, for example, when the temperature of the incinerator 1 exceeds a threshold, the control device (not shown) decreases the aperture of valve V4a and increases the aperture of valve V4b in order to increase the thermal energy recovered by the air cooler 4. On the other hand, for example, when the temperature of the incinerator 1 falls below the threshold, the control device (not shown) increases the aperture of valve V4a and decreases the aperture of valve V4b in order to decrease the thermal energy recovered by the air cooler 4.

[0058] In the example shown in FIG. 5, a bypass L29 is provided in the line L26 and the line L27, connecting before and after the position where the heat medium heater 5 is provided.

[0059] As a result, in the incineration system 500, for example, by adjusting the valve V5 (valve 5a and valve V5b) provided in the bypass L29, it is possible to adjust the amount of fluid supplied to the heat transfer medium heater 5. Specifically, a control device (not shown) controls the opening and closing of the valves V5a and V5b so that the outlet temperature of the heat transfer medium heater 5 becomes a target temperature.

[0060] In addition, in the lines L12 and L13, for example, a bypass (not shown) may be provided connecting before and after the position where the air cooler 4 is provided. This makes it possible in the incineration system 500 to adjust the amount of compressed gas supplied to the incinerator 1. [Explanation of symbols]

[0061] 1: Incinerator 1a: Fluidized bed 2: Turbocharger 2a: Compressor 2b: Turbine 2c: Rotating shaft 3: Fluidized air preheater 4: Air cooler 5: Heat transfer medium heater 6: Cooling tower 7: Dust collector 8: Flue gas treatment tower 9: Chimney 10: Power generation system 20: Dryer 100: Incineration system 200: Incineration system 300: Incineration system 400: Incineration system 500: Incineration system P1: Attractor P2: Pump L11: Line L12: Line L13: Line L21: Line L23: Line L24: Line L25: Line L26: Line L27: Line L28: Bypass L29: Bypass L31: Line V1: Valve V2: Valve V3: Valve V4: Valve V5: Valve

Claims

1. a supercharger having a compressor and a turbine; a first heat exchanger that heats the compressed gas compressed by the compressor using exhaust gas discharged from the incinerator and supplies the heated compressed gas; a second heat exchanger that cools the compressed gas heated in the first heat exchanger by heat exchange with a fluid and supplies the cooled compressed gas to the turbine, The turbine supplies the compressed gas cooled in the second heat exchanger to the incinerator.

2. In claim 1, An incineration system, wherein the second heat exchanger heats the fluid using the compressed gas supplied from the first heat exchanger and supplies the heated fluid to a system other than the incineration system.

3. In claim 2, further comprising: an incineration system having a third heat exchanger that heats the fluid with the exhaust gas and supplies the heated fluid to the other system;

4. In claim 3, an incineration system having a supply line that supplies the fluid supplied from the other system to the second heat exchanger and the third heat exchanger;

5. In claim 4, The supply line is a line that connects the second heat exchanger and the third heat exchanger in parallel, and includes a line that supplies a portion of the fluid supplied from the other system to the second heat exchanger, and a line that supplies another portion of the fluid supplied from the other system to the third heat exchanger.

6. In claim 4, The supply line is a line that connects the second heat exchanger and the third heat exchanger in series, and includes a line that supplies the fluid supplied from the other system to the second heat exchanger, and a line that supplies the fluid supplied from the second heat exchanger to the third heat exchanger downstream of the second heat exchanger.

7. Incinerator and a supercharger having a compressor and a turbine; a first heat exchanger that heats the compressed gas compressed by the compressor using exhaust gas discharged from the incinerator and supplies the heated compressed gas; Other systems that operate with heat supplied via a fluid; a second heat exchanger that heats the fluid by heat exchange with the compressed gas whose temperature has been raised in the first heat exchanger, and supplies the heated fluid to the other system, and that cools the compressed gas whose temperature has been raised in the first heat exchanger by heat exchange with the fluid, and supplies the cooled compressed gas to the turbine, The turbine supplies the compressed gas cooled in the second heat exchanger to the incinerator.

8. The first heat exchanger heats the compressed gas compressed by the compressor using exhaust gas discharged from the incinerator, and supplies the heated compressed gas; a second heat exchanger that cools the compressed gas heated in the first heat exchanger by heat exchange with a fluid and supplies the cooled compressed gas; A turbine supplies the compressed gas cooled in the second heat exchanger to the incinerator.

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