JP6800594B2 - Waste treatment equipment and how to operate the waste treatment equipment - Google Patents

Description

The present invention relates to a waste treatment facility and a method for operating a waste treatment facility.

Various sewage is purified by biological treatment using microorganisms and then discharged into rivers or reused. A large amount of sludge generated by such biological treatment is dehydrated and then landfilled in a final disposal site, or incinerated or melted.

Patent Document 1 discloses a waste treatment facility using a supercharger for the purpose of efficiently reducing the amount of auxiliary fuel used.

The waste treatment facility is located between an incinerator, a supercharger having a compressor and a turbine connected via a rotating shaft, and an exhaust gas discharged from the incinerator and an oxygen-containing gas supplied from the supercharger. It is equipped with a first heat exchanger that exchanges heat with the first heat exchanger, the compressor is configured to be able to supply the sucked oxygen-containing gas to the first heat exchanger using the power transmitted via the rotating shaft, and the turbine is the first. The rotating shaft is rotated by using the energy of the oxygen-containing gas that has passed through the heat exchanger, and the oxygen-containing gas after using the energy can be supplied to the incinerator. Further, a second heat exchanger capable of exchanging heat between the oxygen-containing gas and the exhaust gas after using energy in the turbine is further provided.

Japanese Unexamined Patent Publication No. 2015-152258

In the conventional waste treatment facility described above, the oxygen-containing gas compressed by the compressor and passed through the first heat exchanger is sent to the turbine so that the oxygen-containing gas can be preheated above the heat-resistant temperature of the supercharger. Since it is configured to be further preheated by the second heat exchanger after a part of the energy is consumed, the amount of auxiliary fuel used can be reduced.

However, since the high-temperature oxygen-containing gas that has passed through the first heat exchanger is further preheated by the second heat exchanger, the second heat exchanger is exposed to a harsh high-temperature environment, which is the key to the second heat exchanger. The part sometimes received a large reaction force due to thermal stress.

In view of the above-mentioned problems, an object of the present invention is to provide a waste treatment facility and a method for operating the waste treatment facility, which can operate the furnace safely and efficiently without damaging the high temperature heat exchanger.

In order to achieve the above object, the first characteristic configuration of the waste treatment facility according to the present invention is a waste treatment facility provided with a heat treatment furnace for incinerating waste such as sludge, and the furnace of the heat treatment furnace. A first heat exchanger that preheats combustion air by the heat of internal combustion and / or the possessed heat of exhaust gas guided to the flue, a turbine that rotates by the combustion air preheated by the first heat exchanger, and the turbine. A supercharger including a compressor that supplies combustion air to the first heat exchanger by rotation of the first heat exchanger, and combustion air that is arranged in series or in parallel with the first heat exchanger and exhausted from the turbine. A second heat exchanger to be preheated, an air supply path for supplying combustion air preheated by the second heat exchanger to the heat treatment furnace, and cooling for supplying protective cooling air to the second heat exchanger. It is configured with an air supply mechanism, the supercharger is configured with a plurality of superchargers connected in series, and the cooling air supply mechanism is compressed by a first-stage or intermediate-stage compressor and the compressor. It is provided with a branch path for branching and supplying a part of the compressed air as the cooling air to the second heat exchanger .

A part of the compressed air compressed by the compressor is branched and supplied to the second heat exchanger through the branch path, so that the second heat exchanger can be cooled properly without preparing another blower or compressor. You will be able to. When using a single turbocharger, if a part of the compressed air from the compressor is supplied to the second heat exchanger as cooling air, the amount of expansion work in the turbine will decrease, and the efficiency of using the turbocharger will decrease. However, if multiple turbochargers are connected in series, even if a part of the combustion air compressed by the compressor in the first stage or the intermediate stage is used as the cooling air for the second heat exchanger, the remaining compressed air can be used. Further, by compressing with the compressor in the subsequent stage and then preheating with the first heat exchanger, a sufficient expansion work amount in the turbine can be secured. Therefore, it can be satisfactorily used as cooling air for protection of the second heat exchanger without preparing another blower or compressor, which has a high equipment cost and power cost.

In the second feature configuration, in addition to the first feature configuration described above, the supercharger is configured to include a two-stage supercharger connected in series, and the cooling air supply mechanism is a first-stage compressor. It is provided with a branch path for branching and supplying a part of the compressed air compressed by the compressor as the cooling air to the second heat exchanger.

If two-stage turbochargers are connected in series, even if part of the combustion air compressed by the first-stage compressor is used as cooling air for the second heat exchanger, the remaining compressed air is further compressed by the subsequent-stage compressor. By preheating with the first heat exchanger after this, a sufficient amount of expansion work in the turbine can be secured.

In addition to the first or second feature configuration described above, the third feature configuration includes a temperature sensor that measures the temperature of the second heat exchanger cooled by the cooling air, and a measured value of the temperature sensor. The point is that the cooling air volume adjusting mechanism for adjusting the cooling air volume passing through the branch path is provided.

Severe temperature conditions that damage the second heat exchanger by adjusting the cooling air volume that passes through the branch path using the temperature of the second heat exchanger measured by the temperature sensor as an index by the cooling air volume adjustment mechanism. Since the operation underneath is prevented and the amount of cooling air passing through the branch path can be adjusted to the minimum necessary, it becomes possible to supply sufficiently preheated combustion air to the heat treatment furnace. Further, for example, when a push-in blower for pre-compressing and supplying combustion air to the compressor is provided, the increase in the rotation speed of the push-blower can be adjusted to the minimum necessary to suppress the power.

In the fourth characteristic configuration, in addition to any of the above-mentioned first to third characteristic configurations, a bypass air passage that bypasses the first heat exchanger is provided, and combustion air that passes through the bypass air passage is provided. It is equipped with a hot air furnace for heating.

When the heat treatment furnace is started, the waste heat of the furnace cannot be utilized, and pressure loss occurs due to the ventilation of the air passage and the heat exchanger. However, the ventilation path can be shortened by bypassing the first heat exchanger when the heat treatment furnace is started, and the combustion air can be heated by the hot air furnace to supply heat to the turbine and raise the temperature of the heat treatment furnace. become. Even after the heat treatment furnace is started up, the preheated air temperature can be adjusted by adjusting the amount of air blown to the bypass air passage, so the amount of pressure boosted by the turbocharger and the temperature of the heat treatment furnace can also be adjusted. Become.

The fifth characterizing feature of the from the first upper mentioned in addition to the fourth one characteristic feature of the lies in that further includes the indentation blower for supplying combustion air to the compressor and precompressed.

Since the combustion air precompressed by the indentation blower is supplied to the compressor via the blower passage, the compressed air is preheated by the first heat exchanger not only in the compressor but also in the indentation blower. In other words, since the compression work by the push-in blower is increased to the compression work by the compressor, the combustion air should be sufficiently supplied even if the loss such as the ventilation pressure loss that occurs when the combustion air is supplied to the heat treatment furnace is subtracted. Can be done. Further, since the power of the push-in blower required for that purpose is suppressed by the action of the combustion air passing through the supercharger and the first heat exchanger, the operating cost can be reduced as a whole.

The first characteristic configuration of the furnace operating method of the waste treatment equipment according to the present invention is the furnace operating method of the waste treatment equipment provided with the heat treatment furnace for incinerating waste such as sludge, and the combustion air is used. The compression step compressed by the compressor and the combustion air compressed in the compression step are guided to the first heat exchanger provided in the heat treatment furnace and / or the flue of the heat treatment furnace and preheated by the retained heat of the exhaust gas. A first preheating step, a compression power generation step of rotating a turbine with combustion air preheated in the first preheating step to transmit power to the compressor, and a combustion power exhausted from the turbine in the compression power generation step. The air was led to a second heat exchanger arranged in series or in parallel with the first heat exchanger, and further preheated by the retained heat of the exhaust gas, and reheated in the second preheating step. A combustion air supply step of supplying combustion air to the heat treatment furnace, a cooling air supply step of supplying protective cooling air supplied to the second heat exchanger to the second heat exchanger, and the cooling. look including a cooling air volume adjusting step of adjusting the air volume of the cooling air by the second temperature of the heat exchanger which is cooled by air, the compression step to be compressed in a plurality of stages of compressors connected in series In addition to being configured, the compression power generation process is configured to rotate a plurality of stages of turbines connected in series to transmit power to each compressor, and the cooling air supply process is compressed by a first stage or intermediate stage compressor. The point is that a part of the compressed air is branched and supplied to the second heat exchanger as the cooling air .

The second feature configuration is that, in addition to the first feature configuration described above, a precompression step of precompressing the combustion air guided to the compression step by a push blower is further provided.

As described above, according to the present invention, it has become possible to provide a waste treatment facility and a method for operating a waste treatment facility that can operate the furnace safely and efficiently without damaging the high-temperature heat exchanger. It was.

Explanatory drawing of waste treatment equipment by this invention (A) is an explanatory view of the second heat exchanger, and (b) is an enlarged explanatory view of a main part of the second heat exchanger. Explanatory drawing of waste treatment facility which shows another embodiment Explanatory drawing of waste treatment facility which shows another embodiment Explanatory drawing of waste treatment facility which shows another embodiment Explanatory drawing of waste treatment facility which shows another embodiment Explanatory drawing of the second heat exchanger showing another embodiment Explanatory drawing of the second heat exchanger showing another embodiment Explanatory drawing of waste treatment facility which shows another embodiment

Hereinafter, embodiments of the waste treatment facility and the method for operating the furnace of the waste treatment facility according to the present invention will be described.

FIG. 1 shows a waste treatment facility 100 that incinerates waste such as sludge. The waste treatment facility 100 includes a sludge storage tank 1 in which sludge to be incinerated is stored, a sludge input mechanism 11, a fluidized bed incinerator 2 which is an example of a waste treatment furnace, an exhaust gas treatment facility, and the like. I have.

In the fluidized bed incinerator 2, the sludge supplied from the sludge charging mechanism 11 is charged into the fluidized bed formed by the high temperature air supplied from the air supply mechanism 3 and heated, and the gasified sludge is discharged to the free board section. It is a processing furnace that burns at 20. Below the freeboard section 20, a temperature rising burner 21 that heats the inside of the furnace at the time of startup is arranged, and an auxiliary burner 22 that supplements the amount of heat required for burning sludge after the temperature of the furnace has risen is provided.

A second heat exchanger 4, a first heat exchanger 5, and a dust collector 6, which collects soot and dust, preheat the combustion air by the possessed heat of the exhaust gas, in order along the flue 10 of the fluidized bed incinerator 2. A flue treatment tower 7 or the like that sprays an alkaline agent to neutralize the acidic gas component in the exhaust gas is arranged.

An attractive blower 8 is provided on the downstream side of the smoke exhaust treatment tower 7 to attract the exhaust gas of the flue 10 and maintain the inside of the furnace at a negative pressure, and the exhaust gas attracted by the attractive blower 8 is purified by each exhaust gas treatment facility. After that, it is exhausted from the chimney 9.

The air supply mechanism 3 described above includes a push-in blower 30, a two-stage turbocharger 40, 50 connected in series, and a two-stage heat exchanger of a first heat exchanger 5 and a second heat exchanger 4. It is configured to prepare.

The first-stage turbocharger 40 located on the upstream side along the flow of combustion air is provided with a compressor 40c and a turbine 40t rotatably connected by a drive shaft 40a, and the turbocharger 50 on the downstream side is a drive shaft. It includes a compressor 50c and a turbine 50t that are integrally rotatably connected at 50a.

In the present embodiment, the combustion air precompressed to about 5 kPa by the indentation blower 30 is supplied to the air supply port of the compressor 40c constituting the supercharger 40 and compressed to about 70 kPa, and the compressed combustion air is Further, it is supplied to the air supply port of the compressor 50c constituting the supercharger 50 in the subsequent stage, compressed to about 300 to 400 kPa, and then supplied to the first heat exchanger 5.

Combustion air that has been heat-exchanged with exhaust gas at 700 to 900 ° C. in the first heat exchanger 5 and preheated to 500 to 750 ° C. is supplied to the turbine 50t in the subsequent stage, the turbine 50t is rotationally driven, and the drive shaft 50a is further driven. The compressor 50c connected to the above is driven to rotate.

Combustion air discharged from the turbine 50t at 400 to 650 ° C. and about 70 kPa is further supplied to the turbine 40t so that the turbine 40t is rotationally driven and the compressor 40c connected to the drive shaft 40a is also rotationally driven. become.

The compressed air of 300 to 550 ° C. and about 40 kPa discharged from the turbine 40t is further supplied to the second heat exchanger 4 and exchanged with the exhaust gas of 800 to 1000 ° C. and reheated to 500 to 750 ° C. Is supplied to the fluidized bed incinerator 2 as fluidized and combustion air to form a fluidized bed. The pressure described in this specification is a gauge pressure.

As a blower pipe 41 that supplies a part of the compressed air compressed by the compressor 40c to the second heat exchanger 4 as protective cooling air in the pipeline connecting the upstream compressor 40c and the downstream compressor 50c. A functioning branch road is provided. The pressure of the compressed air supplied through the blower pipe 41 is about 70 kPa, and the pressure of the combustion air supplied from the turbine 40t to the second heat exchanger 4 is about 40 kPa. That is, the pressure of the cooling air is set to be higher than the pressure of the combustion air. The above-mentioned operating conditions such as temperature and pressure of each part are examples when the present invention is carried out, and the operating conditions are not limited to these values.

As shown in FIG. 2, in the second heat exchanger 4, a plurality of heat transfer tubes 4e are arranged in a vertical position in a tubular casing 4a, and the heat transfer tubes 4e are welded and supported by the upper and lower tube plates 4c and 4d. It is a countercurrent multi-tube heat exchanger.

The exhaust gas flowing out of the fluidized bed incinerator 2 flows down through the flue 10 and flows into the exhaust gas inflow header 4f provided in the upper part of the casing 4a, and is provided in the lower part of the casing 4a through each heat transfer tube 4e. The combustion air flows out to the exhaust gas outflow header 4g, flows into the casing 4a from the air inflow portion 4h provided below the casing 4a, and flows out from the air outflow portion 4i provided above the casing 4a. It is configured. Further, a plurality of baffle plates 4j are arranged in the casing 4a so that heat can be efficiently exchanged between the air and the heat transfer tube 4e.

The upper pipe plate 4c is doubly configured so that a cooling space S is formed inside, and a cooling air outflow pipe 4 m is provided in the central portion of the lower pipe plate 4c. The cooling air from the blower pipe 41 described above is supplied from the cooling air inflow portion 4n arranged above the casing 4a, and the cooling air flowing into the cooling space S is used for combustion through the outflow pipe 4m provided on the pipe plate 4c. It is configured to merge with the air and flow out from the air outflow section 4i together with the combustion air.

That is, a cooling air supply mechanism 60 is configured to supply the second heat exchanger 4 with cooling air for protection having a higher pressure than the combustion air supplied to the second heat exchanger 4 by the compressor 40c and the blower pipe 41. ..

Returning to FIG. 1, the combustion air precompressed by the indentation blower 30 is compressed to a high pressure by the compressor 40c of the supercharger 40 and the compressor 50c of the supercharger 50 in the subsequent stage, and then guided to the first heat exchanger 5. It is preheated.

Even if a part of the compressed air obtained by the compressor 40c is branched and supplied as the cooling air of the second heat exchanger 4, the turbine 50t and the turbine 40t have sufficient expansion work because the push-in blower 30 and the compressor 50c are provided. It becomes possible to supply combustion air at a pressure higher than the ventilation pressure loss when forming the fluidized bed in the fluidized bed type incinerator 2 while stably operating the superchargers 40 and 50.

The waste treatment facility 100 is provided with a control unit 70. The fluidized bed incinerator 2 is suitable for the control unit 70 by controlling the rotation speed of the push blower 30 based on the oxygen concentration of the exhaust gas detected by the oxygen gas sensor Sg provided at the outlet of the free board unit 20. It is configured to adjust the amount of combustion air supplied to the fluidized bed incinerator 2 so that it is maintained in the combustion state.

The control unit 70 calculates the target air amount to be supplied to the furnace by performing a predetermined control calculation based on the deviation between the oxygen concentration of the exhaust gas detected by the oxygen gas sensor Sg and the target oxygen concentration. The amount of air required for complete combustion is set based on the theoretical amount of air assumed in advance, and the reference oxygen concentration remaining in the exhaust gas at that time is calculated. A feedback calculation is performed so that the target air amount is reduced when the oxygen concentration of the exhaust gas detected by the oxygen gas sensor Sg is higher than the reference oxygen concentration, and the target air amount is increased when the oxygen concentration of the exhaust gas is lower than the reference oxygen concentration. Is done.

Further, the control unit 70 calculates the target rotation speed of the push blower 30 based on the deviation between the air amount detected by the flow meter M installed between the push blower 30 and the compressor 40C and the target air amount. The inverter 75 is controlled so that the push-in blower 30 reaches the target rotation speed.

By using the oxygen concentration in the exhaust gas as an index, the appropriate amount of combustion air for the organic components of the sludge burned in the fluidized bed incinerator 2 can be grasped, and the target amount is set based on the index. Therefore, it becomes possible to supply combustion air without a large excess or deficiency with respect to the required amount.

The control unit 70 serves as a temperature sensor T for measuring the temperature of the second heat exchanger 4 cooled by the cooling air and a cooling air volume adjusting mechanism for adjusting the cooling air volume passing through the branch path according to the measured value of the temperature sensor T. By adjusting the amount of cooling air passing through the branch path using the temperature of the second heat exchanger 4 measured by the temperature sensor T as an index, the second heat exchanger 4 is severely damaged. It is configured to prevent operation under temperature conditions.

By adopting such a configuration, the amount of cooling air passing through the branch path can be adjusted to the minimum necessary, and sufficiently preheated combustion air can be supplied to the fluidized bed type combustion furnace 2, and the push-in blower 30 can be supplied. It becomes possible to suppress the power by minimizing the increase in the number of revolutions. In FIG. 1, the temperature sensor T and the valve V2 are shown in a simplified manner in which they are connected by a broken line indicating a signal line, but the output signal of the temperature sensor T is actually input to the control unit 70. Then, the opening degree of the valve V2 is controlled by the control unit 70.

The temperature sensor T is preferably installed in the portion of the second heat exchanger 4 where the heat load is maximum, and in the example shown in FIG. 2, it is preferably installed in the upper tube plate 4c. The opening degree of the valve V2 is adjusted by the control unit 70 so that the temperature of the upper tube plate 4c is maintained at, for example, about 600 ° C.

Since the volume of gas changes as the temperature and pressure change, it is necessary to make corrections according to the temperature and pressure when measuring the flow rate. Therefore, if the temperature or pressure deviates from the expected range, the error becomes large. Therefore, it is desirable to install the flowmeter M in a place where there is little change in temperature or pressure if possible. The change in temperature and pressure is the smallest on the inflow side of the air to the push-in blower, but a new pipe for installing the flow meter M is required. Further, since the temperature and / or pressure rises on any of the outlet side of the compressor, the outlet side of the heat exchanger, and the outlet side of the turbine, it is necessary to provide a flow meter M in the air passage from the indentation blower to the compressor. preferable.

Further, the method of adjusting the supply amount of combustion air by the push-in blower 30 is not a method of adjusting by receiving resistance of a damper mechanism or the like which causes an increase in power cost, but a method of controlling the rotation speed of the push-in blower 30. By this method, in addition to being able to suppress the power cost and the device cost, it is possible to provide a simpler control method.

That is, in the above-mentioned waste treatment facility, the compression step of compressing the combustion air with a compressor and the combustion air compressed in the compression step are guided to the first heat exchanger provided in the flue of the heat treatment furnace to exhaust the exhaust gas. It was exhausted from the turbine in the first preheating process, which preheats with the retained heat, the compression power generation process, in which the combustion air preheated in the first preheating process rotates the turbine and transmits the power to the compressor, and the compression power generation process. For combustion, the second preheating step in which the combustion air is guided to the second heat exchanger arranged in series with the first heat exchanger and further preheated by the retained heat of the exhaust gas, and the second preheating step reheated. A combustion air supply process that supplies air to the heat treatment furnace, a cooling air supply process that supplies protective cooling air at a higher pressure than the combustion air supplied to the second heat exchanger, and cooling. A method of operating a waste treatment facility including a cooling air volume adjusting step of adjusting the air volume of cooling air according to the temperature of a second heat exchanger cooled by air is realized.

The compression process is configured to be compressed by a multi-stage compressor connected in series, and the compression power generation process is configured to rotate a multi-stage turbine connected in series to transmit power to each compressor. The cooling air supply step is configured so that a part of the compressed air compressed by the compressor in the first stage or the intermediate stage is branched and supplied to the second heat exchanger as the cooling air.

Hereinafter, another embodiment of the present invention will be described.
As shown in FIG. 3, in order to adjust the temperature of the compressed air supplied into the furnace, along the flow direction of the exhaust gas flowing through the heat transfer tube arranged in the second heat exchanger 4, the most downstream side and the most downstream side Air inflow sections 4h and 4h'that supply combustion air are provided at two locations on the upstream side, and the amount of air that flows in from the air inflow section 4h and the air inflow section 4h'is provided between the air inflow section 4h and 4h'. It may be configured to be adjustable by the valve V1.

By adjusting the opening degree of the valve V1, the temperature of the combustion air supplied to the fluidized bed incinerator 2 can be adjusted to the target temperature.

In the above-described embodiment, the example in which the inverter 75 is controlled so that the push-in blower 30 reaches the target rotation speed has been described, but it is also possible to configure the inverter 75 without using the inverter 75.

As shown in FIG. 4, for example, a valve V3 is provided in the ventilation path between the push-in blower 30 and the compressor 40c, a valve V4 that can open the ventilation path to the atmosphere is provided, and the valves V3 and V4 are opened by the control unit 70. The air volume may be adjusted by controlling the degree.

Further, when the furnace is started up, the valve V3 is opened to blow air from the push-in blower 30, and after the furnace is started up, the valve V4 is opened to allow suction of outside air, so that it is necessary even if the push-in blower 30 does not blow air. It may be configured so that the supply amount of combustion air can be secured.

Further, when the fluidized bed incinerator 2 incinerates an object to be processed having a high calorific value, a cooling mechanism or a heat extraction mechanism for lowering the temperature inside the furnace may be provided in order to suppress the combustion temperature.

For example, a cooling device provided with a two-fluid nozzle may be installed in the fluidized bed portion, or a cooling device provided with a water spray mechanism may be arranged in the freeboard portion. The control unit 70 can adjust the amount of water sprayed from the two-fluid nozzle and the amount of water sprayed from the water spray mechanism, and the temperature can be adjusted by utilizing the latent heat of vaporization.

As shown in FIG. 5, the second heat exchanger 4 and the first heat exchanger 5 arranged in the flue 10 may be arranged so as to be arranged in parallel along the flow direction of the exhaust gas.

FIG. 6 shows a preferable configuration for smoothly starting up the waste treatment facility shown in FIG. A bypass air passage 13 that bypasses the first heat exchanger 5 is provided, and a hot air furnace 15 that heats the combustion air passing through the bypass air passage 13 is provided. Further, a valve V5 is provided near the upstream side of the first heat exchanger 5, and a valve V6 is provided on the upstream side of the hot air furnace 15 of the bypass air passage 13.

At the time of startup, the valve V5 is closed and the valve V6 is opened, and the combustion air from the push-in blower 30 is heated by the hot air furnace 15 and supplied to the turbines 50t and 40t. By adjusting the opening of the valve V5 gradually to be larger and the opening of the valve V6 to be smaller according to the degree of temperature rise in the furnace, the amount of air distributed to the first heat exchanger 5 is increased, and the hot air furnace is operated in steady operation. Stop 15 to reduce fuel consumption.

Since the preheated air temperature can be adjusted by adjusting the amount of ventilation to the bypass air passage 13, it is possible to control the amount of pressure boosted by the superchargers 40 and 50 and the combustion temperature of the fluidized bed incinerator. .. It is also possible to use the heating burner 21 of the furnace at the same time at the time of start-up, and only one of them may be used. When only one of them is used, it is preferable to use the hot air furnace 15 from the viewpoint of uniform heating in the furnace.

When the heat treatment furnace is started up, the waste heat of the furnace cannot be utilized, and pressure loss occurs due to the ventilation of the air passage and the heat exchanger. However, the ventilation path can be shortened by bypassing the first heat exchanger when the heat treatment furnace is started up, and by heating the combustion air with the hot air furnace, the heat supply to the turbine and the temperature rise of the heat treatment furnace can be increased. It will be possible. Even after the heat treatment furnace is started up, the preheated air temperature can be adjusted by adjusting the amount of air blown to the bypass air passage, so the amount of pressure boosted by the turbocharger and the temperature of the heat treatment furnace can also be adjusted. Become.

In the above-described embodiment, an example in which the first heat exchanger 5 and the second heat exchanger 4 are configured to preheat the compressed air by the retained heat of the exhaust gas guided to the flue 10 has been described. 1 Both or one of the heat exchanger 5 and the second heat exchanger 4 may be installed in the free board portion of the fluidized bed incinerator 2 so as to preheat the compressed air by the heat of combustion in the furnace. ..

In the above-described embodiment, a two-stage turbocharger connected in series is provided, and the cooling air supply mechanism branches the first-stage compressor and a part of the compressed air compressed by the compressor as cooling air to the second heat exchanger. Although an example composed of a branch path to be supplied has been described, the number of stages of the turbocharger is not limited to two.

That is, a plurality of turbochargers connected in series are provided, and the cooling air supply mechanism branches and supplies the compressor of the first stage or the intermediate stage and a part of the compressed air compressed by the compressor as cooling air to the second heat exchanger. It may be composed of a branch road.

Further, a dedicated compressor or blower fan that supplies the second heat exchanger with protective cooling air having a pressure higher than that of the combustion air may be configured as the cooling air supply mechanism. That is, it is rotated by the first heat exchanger that preheats the combustion air by the combustion heat in the heat treatment furnace and / or the possessed heat of the exhaust gas guided to the flue, and the combustion air preheated by the first heat exchanger. A supercharger including a turbine and a compressor that supplies combustion air to the first heat exchanger by rotation of the turbine, and combustion air that is arranged in parallel or in series with the first heat exchanger and exhausted from the turbine. The second heat exchanger to be further preheated, the air supply path for supplying the combustion air preheated by the second heat exchanger to the heat treatment furnace, and the protection of a higher pressure than the combustion air supplied to the second heat exchanger. It suffices to include a cooling air supply mechanism for supplying cooling air for use to the second heat exchanger.

In the above-described embodiment, each of the turbochargers is provided in series, and the cooling air supply mechanism uses a first-stage or intermediate-stage compressor and a part of the compressed air compressed by the compressor as cooling air. An example composed of a branch path for branching and supplying to the heat exchanger has been described, but as a cooling air supply mechanism, as shown in FIG. 9, a single supercharger 40 is provided, and the supercharger 40 is provided. It may be composed of a compressor 40c and a blower pipe 41 (60) as a branch path for branching and supplying a part of the compressed air compressed by the compressor 40c as cooling air to the second heat exchanger 4.

FIG. 7 shows another embodiment of the second heat exchanger 4. Hereinafter, the differences from the configuration shown in FIG. 2 will be mainly described. The upper pipe plate 4c is doubly configured so that a cooling space S is formed inside, and an inflow pipe 4r for cooling air is provided in the central portion of the lower pipe plate 4c. The cooling air from the blower pipe 41 described above is supplied from the cooling air inflow portion 4n arranged in the upper part of the casing 4a, and a part of the cooling air flows into the cooling space S through the inflow pipe 4r provided in the pipe plate 4c. However, it is configured to flow out from the cooling air outflow portion 4p to the outside. The rest of the cooling air supplied from the cooling air inflow section 4n joins the combustion air and flows out from the air outflow section 4i. When adopting this configuration, it is necessary to set the amount of the cooling air supplied from the cooling air inflow section 4n including the amount returned to the combustion air to the amount of branched air from the blower pipe 41.

FIG. 8 shows yet another embodiment of the second heat exchanger 4. Hereinafter, the differences from the configuration shown in FIG. 2 will be mainly described. A sleeve tube 4k that fits each heat transfer tube 4e externally or internally is welded to the tube plate 4c, and the heat transfer tube 4e that thermally expands in the axial direction slides and moves with respect to the sleeve tube 4k, so that the tube plates 4c and 4d It is configured to suppress the distortion of.

Further, a partition pipe plate 4q is arranged so as to face the pipe plate 4c on the exhaust gas inflow header 4f side, and a cooling space S in which cooling air is introduced is formed in a gap sandwiched between the pipe plates 4c and 4q, and thermal stress is generated. It is configured so that the distortion of the tube plate 4c generated by the reaction force against the air is suppressed. The partition pipe plate 4q is welded to only one of the heat transfer pipes 4e and the casing 4a.

As described above, since the pressure of the combustion air is lower than the pressure of the cooling air inside the second heat exchanger 4, the cooling air supplied to the cooling space S is not in the heat transfer tubes 4e or the casing 4a. It is mixed into the combustion air through the gap of the welded portion, or is mixed into the exhaust gas side through the gap between the sleeve tube 4k and the heat transfer tube 4e. The pressure of the exhaust gas is maintained at a negative pressure by the attracting blower 8.

In the above-described embodiment, the case where the fluidized bed incinerator 2 is adopted as the heat treatment furnace has been described, but the incinerator to which the present invention is applied is not limited to the fluidized bed incinerator 2, but also the fluidized bed incinerator 2. Similarly, it can be applied to other types of industrial furnaces such as shaft furnaces having a large air pressure loss. For example, a heat treatment furnace or scrap that melts by throwing sludge from above a shaft furnace having a coke bed formed at the bottom and a tuyere for supplying combustion air to the coke bed is thrown in and melted. The present invention can be applied even to a cupola or the like.

Each of the above-described embodiments is an example of the present invention, and the present invention is not limited by the description thereof. Each characteristic configuration may be appropriately faced with each other, and a specific configuration of each part of the present invention may be used. Needless to say, it may be appropriately modified and designed within the range in which the action and effect are exhibited.

100: Waste treatment equipment 2: Flow bed type incinerator 3: Air supply mechanism 4: Second heat exchanger 5: First heat exchanger 10: Smoke path 30: Push-in blower 40: Supercharger 40c: Compressor 40t: Turbine 50: Supercharger 50c: Compressor 50t: Turbine 60: Cooling air supply mechanism 70: Control unit

Claims (7)

It is a waste treatment facility equipped with a heat treatment furnace that incinerates waste such as sludge.
A first heat exchanger that preheats the combustion air by the heat of combustion in the furnace and / or the heat of the exhaust gas guided to the flue.
A supercharger including a turbine rotated by combustion air preheated by the first heat exchanger and a compressor that supplies combustion air to the first heat exchanger by rotation of the turbine.
A second heat exchanger, which is arranged in series or in parallel with the first heat exchanger and further preheats the combustion air exhausted from the turbine,
An air supply path for supplying combustion air preheated by the second heat exchanger to the heat treatment furnace, and
A cooling air supply mechanism that supplies protective cooling air to the second heat exchanger,
Is configured to include a,
The turbocharger includes a plurality of turbochargers connected in series.
The cooling air supply mechanism is a waste treatment facility including a compressor in the first stage or an intermediate stage and a branch path for branching and supplying a part of the compressed air compressed by the compressor as the cooling air to the second heat exchanger. .. The supercharger example Bei the supercharger of the two-stage connected in series,
The cooling air supply mechanism wastes according to claim 1, characterized in that a branch for supplying the branch passage to the second heat exchanger part of air compressed by the first-stage compressor and the compressor as the cooling air Processing equipment. A temperature sensor that measures the temperature of the second heat exchanger cooled by the cooling air, and
A cooling air volume adjusting mechanism that adjusts the cooling air volume passing through the branch path based on the measured values of the temperature sensor, and
The waste treatment facility according to claim 1 or 2 . The waste treatment facility according to any one of claims 1 to 3 , further comprising a bypass air passage that bypasses the first heat exchanger and a hot air furnace that heats combustion air passing through the bypass air passage. The waste treatment facility according to any one of claims 1 to 4 , further comprising a push-in blower that precompresses and supplies combustion air to the compressor. It is a method of operating a waste treatment facility equipped with a heat treatment furnace that incinerates waste such as sludge.
A compression process that compresses combustion air with a compressor,
A first preheating step in which the combustion air compressed in the compression step is guided to a first heat exchanger provided in the heat treatment furnace and / or the flue of the heat treatment furnace and preheated by the retained heat of the exhaust gas.
A compression power generation step of rotating a turbine with combustion air preheated in the first preheating step and transmitting power to the compressor.
A second heat exchanger in which the combustion air exhausted from the turbine in the compression power generation step is guided to a second heat exchanger arranged in series or in parallel with the first heat exchanger and further preheated by the retained heat of the exhaust gas. Preheating process and
A combustion air supply step of supplying the combustion air reheated in the second preheating step to the heat treatment furnace, and a combustion air supply step.
A cooling air supply step of supplying the protective cooling air supplied to the second heat exchanger to the second heat exchanger, and
A cooling air volume adjusting step of adjusting the air volume of the cooling air according to the temperature of the second heat exchanger cooled by the cooling air, and a cooling air volume adjusting step.
Only including,
The compression process is configured to be compressed by a multi-stage compressor connected in series, and is also compressed.
The compression power generation process is configured to rotate a plurality of stages of turbines connected in series to transmit power to each compressor.
The cooling air supply step is a method for operating a waste treatment facility in which a part of compressed air compressed by a compressor in the first stage or an intermediate stage is branched and supplied to the second heat exchanger as the cooling air. .. The method for operating a furnace of a waste treatment facility according to claim 6 , further comprising a precompression step of precompressing the combustion air guided to the compression step by a blower.

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