JP5421567B2 - Waste treatment facilities and methods of using recovered heat in waste treatment facilities - Google Patents

Description

  The present invention relates to a waste treatment facility for reducing the volume of waste, such as sewage sludge, municipal waste, and industrial waste, by incineration, pyrolysis gasification, melting, and the like, and a method of using recovered heat in the waste treatment facility. In particular, the present invention relates to a waste treatment facility capable of reducing maintenance costs, improving an operating rate, and improving power generation, and a method of using recovered heat in the waste treatment facility.

  In recent years, it has become possible to simultaneously reduce the volume of waste, such as sewage sludge, municipal waste, and industrial waste, and to make ash harmless, improve waste treatment performance, and reduce carbon monoxide emissions. For the reduction, there is a waste treatment facility that recovers heat of exhaust gas and preheats combustion air and melting air supplied to a gasification furnace and a melting furnace. As such a waste treatment facility, for example, those described later are known.

  First, the technology according to Conventional Example 1 is an exhaust gas treatment facility for a waste incinerator, and this exhaust gas treatment facility is configured as shown in FIG. That is, the high-temperature acidic gas removing agent charging device 52 for introducing the high-temperature acidic gas removing agent into the flow path of the exhaust gas discharged from the incinerator 50 and the exhaust gas into which the high-temperature acidic gas removing agent has been introduced are introduced and collected. A high temperature dust collector 51 that performs dust treatment, a waste heat boiler 54 that recovers heat by introducing exhaust gas discharged from the high temperature dust collector 51, and an organic gas that introduces exhaust gas discharged from the waste heat boiler 54 It comprises a catalytic reactor 55 for decomposing chlorinated compounds, a heat recovery device 56 for recovering heat from the exhaust gas discharged from the catalyst reactor 55, and an activated carbon adsorption tower 57 for removing harmful components from the exhaust gas after heat recovery. (For example, refer to Patent Document 1).

  The technology according to Conventional Example 2 is a method for preheating waste incinerator air using a chimney, and this method for preheating waste incinerator air includes waste incinerator exhaust gas and air flowing through an exhaust gas discharge inner cylinder of the chimney. By exchanging heat with air, the heat of the exhaust gas is used to preheat the air, and the preheated air is supplied to the incinerator. More specifically, FIG. 6A is a flowchart showing a method for preheating air, and FIG. 6B is a sectional view of a chimney. That is, a heat insulating material 69 such as rock wool is coated on the outside of the exhaust gas discharge inner cylinder 68 in the chimney 67, and an air chamber 70 is formed between the exhaust gas discharge inner cylinder 68 and the outer design wall 71. The combustion air supplied to the incinerator 72 is preheated using the air chamber 70 of the chimney 67.

  The preheated air is supplied to the air chamber 70 from an openable / closable vent 62 below the chimney 67 and rises while being gradually warmed by the heat of the exhaust gas sent to the exhaust gas discharge inner cylinder 68 by the induction fan 66. The warmed air is configured to be supplied from the upper outlet 74 to the incinerator 72 by the blower 73. In order to prevent low temperature corrosion, the outer surface of the exhaust gas discharge inner cylinder 68 is configured such that the wall temperature of the inner wall of the exhaust gas discharge inner cylinder 68 is equal to or higher than the acid dew point temperature (about 140 to 150 ° C.) (for example, (See Patent Document 2).

  The technology according to Conventional Example 3 is a “exhaust gas treatment method during waste incineration” that recovers exhaust heat from exhaust gas during waste incineration while preventing generation of dioxins. More specifically, as shown in FIG. 7 of the process chart of the exhaust gas treatment method, high-temperature exhaust gas at 800 to 950 ° C. discharged from the incinerator 81 is introduced into the gas quench tower 82, and a large amount of water is injected to dioxin. It is cooled at once to 150-200 ° C. below the production temperature range. Next, after a low-temperature exhaust gas containing a large amount of water vapor is guided to the dust collector 83 and dust is removed, a thermoelectric element that directly converts the through-flow heat from the low-temperature exhaust gas to the cooling water for exhaust gas cooling into electric power is incorporated. It is sent to a waste heat recovery tower 85 equipped with a heat exchange pipe.

Then, the temperature of the exhaust gas is lowered to around 60 ° C. by recovering the sensible heat and latent heat of the low temperature exhaust gas through heat exchange with the cooling water for exhaust gas cooling flowing through the heat exchange pipe of the exhaust heat recovery tower 85, and the atmosphere from the chimney 86 is reduced to the atmosphere. Released into. On the other hand, the thermoelectric element converts the through heat from the low temperature exhaust gas to the cooling water for cooling the exhaust gas into electric power, and the electric power load 93 is used for operation of the waste incineration plant. The exhaust gas cooling water is further cooled by the cooling tower 87 and then stored in the cooling water tank 88. The cooling water in the cooling water tank 88 is sent again to the exhaust heat recovery tower 85 by the cooling water pump 89 and cooled. The water temperature is kept at 30 ° C. Then, the condensed water accumulated in the lower part of the exhaust heat recovery tower 85 and the cooling water in the cooling water tank 88 are introduced into the gas quenching tower 82 via the cooling water tank 90 and used for rapid cooling of high-temperature exhaust gas (for example, , See Patent Document 3).
JP 2001-212430 A JP-A-8-110037 JP-A-6-129212

  In the waste gas treatment facility of the waste treatment furnace according to the above-described conventional example 1, the heat recovery device 56 recovers the heat of the exhaust gas from which the high temperature dust collector 51 has removed the high temperature acidic gas removing agent that has captured the dust and acid gas. However, the high temperature dust collector 51 is disposed immediately after the incinerator 50, the temperature of the exhaust gas is 850 ° C. or higher, and the clinker (semi-molten ash) in the high temperature dust collector 51 is attached. It is not realistic because it may cause clogging. Further, the temperature of the exhaust gas introduced into the heat recovery device 56 is 350 ° C., which is high, and it is considered that heat recovery by the waste heat boiler 54 is insufficient. Note that use of the recovered heat recovered by the heat recovery device 56 is not described.

  The conventional example 2 preheats the combustion air supplied to the incinerator 72 using the air chamber 70 formed between the exhaust gas discharge inner cylinder 68 of the chimney 67 and the outer design wall 71. To do. Therefore, since maintenance is performed at a high place, not only the maintenance cost is increased, but also a heat insulating material 69 for preventing burns is wound and the air cannot be preheated to a high temperature, so that it is compared with a normal heat exchanger. Therefore, there is a problem that heat recovery efficiency is also poor. If the heat insulating material 69 for increasing the heat recovery efficiency is not wound, the cylinder surface temperature becomes as high as about 200 ° C., which is a safety problem and, depending on the preheating temperature, enters the exhaust gas discharge inner cylinder 68. The case where it is not possible is assumed.

The conventional example 3 has a problem that the exhaust gas is supercooled (140 to 150 ° C. → 60 ° C.), so that heat is recovered from the low temperature exhaust gas, and the heat recovery rate from the exhaust gas is extremely low. Moreover, in addition to the necessity to incorporate a large number of thermoelectric elements in the heat exchange tubes of the heat recovery tower, the power generated from each individual thermoelectric element must be taken out, and the structure is complicated and maintenance of the equipment is required. There is a problem that the cost increases. Furthermore, for example, to achieve high-temperature air combustion and high-temperature melting, for example, furnace air is heated to 200 ° C., and the heat source for heating is high-pressure steam generated from a waste heat boiler. As described above, since the amount of high-pressure steam used in the steam turbine that drives the generator is reduced due to the use of high-pressure steam to raise the temperature of the furnace air, the amount of power generation has been reduced in recent years. In order to reduce CO ₂ emissions, which are called greenhouse gases, there is a need for further improvements in power generation.

  Accordingly, an object of the present invention is to provide a waste treatment facility capable of reducing maintenance costs, improving an operating rate, and improving power generation, and a method of using recovered heat in the waste treatment facility. is there.

The present invention has been made in view of the above circumstances, and therefore, in order to solve the above problems, the gist of the means adopted by the waste treatment facility according to claim 1 of the present invention is as follows: municipal waste, industrial waste Waste treatment furnace that reduces the volume of waste such as waste, waste heat boiler that generates high-pressure steam using the heat of exhaust gas discharged from this waste treatment furnace, and outflow from this waste heat boiler Dust removal means that captures and removes dust such as fly ash in exhaust gas, an induction blower that sends dust removal gas from which dust has been removed by the dust removal means to the chimney, and high-pressure steam generated by the waste heat boiler In a waste treatment facility comprising a steam turbine that drives a generator using a power source, the heat of the dust removal gas is recovered and supplied to the waste treatment furnace between the dust removal means and the chimney. Furnace air A gas air preheater for preheating is disposed, and the gas air preheater is used between the gas air preheater and the waste treatment furnace using high-pressure steam generated in the waste heat boiler. A high-pressure steam air preheater that preheats the furnace air preheated in the furnace is provided, and the furnace air supply to the gas air preheater is provided between the gas air preheater and the supply source of the furnace air. A low-pressure steam air preheater that recovers and preheats the heat of the low-pressure steam exhausted from the steam turbine; and between the gas air preheater and the high-pressure steam air preheater, The high pressure steam air is communicated between the gas air preheater and the low pressure steam air preheater via a reflux path for recirculating a part of the furnace air preheated by the gas air preheater. and between the preheater and the waste incinerator, and said return path, via the return passage Serial is characterized in that communicated with the second return pipe for recirculating part of preheated oven air at high pressure steam type air preheater.

The summary of the method adopted by the method of using recovered heat in the waste treatment facility according to claim 2 of the present invention is a waste treatment furnace for reducing the volume of waste such as municipal waste and industrial waste, and this disposal A waste heat boiler that generates high-pressure steam using the heat of the exhaust gas discharged from the waste treatment furnace, and a dust removal means that captures and removes dust such as fly ash in the exhaust gas flowing out of the waste heat boiler, Waste treatment equipment comprising an induction blower for sending dust removal gas from which dust has been removed by the dust removal means to a chimney, and a steam turbine for driving a generator using high-pressure steam generated by the waste heat boiler In the method of using recovered heat in the furnace, the heat of the dust removal gas is recovered by a gas air preheater, and the furnace air supplied to the waste treatment furnace is preheated, and the furnace is preheated by the gas air preheater Sky In the supplied to the waste treatment furnace was preheated with high-pressure steam type air preheater utilizing heat of the high-pressure steam generated in the waste heat boiler, the air furnace is supplied to the gas type air preheater, The heat of the low-pressure steam discharged from the steam turbine is recovered and preheated by a low-pressure steam air preheater, and a part of the furnace air preheated by the gas air preheater is passed through the reflux path to the gas. For a furnace pre-heated by the high-pressure steam air preheater , recirculated between the air preheater and the low-pressure steam air preheater, merged with the furnace air preheated by the low-pressure steam air preheater A furnace in which a part of air is recirculated between the gas air preheater and the low pressure steam air preheater via the second reflux path and the reflux path, and is preheated by the low pressure steam air preheater. Characterized by merging with commercial air A.

In the waste processing facility according to claim 1 of the present invention or the method of using recovered heat in the waste processing facility according to claim 2 of the present invention, dust is removed by the dust removing means with respect to the waste processing furnace. Furnace air preheated by a gas air preheater that recovers the heat of the dust removal gas is supplied.

Therefore, according to the method for using recovered heat in the waste treatment facility according to claim 1 of the present invention or the waste treatment facility according to claim 2 of the present invention, the gas air preheater is corroded or dusted. Since there is no clogging, the maintenance cost of the waste treatment facility can be reduced and the operating rate can be improved. Then, by preheating the furnace air with the heat of dust removal gas that has not been used conventionally, a large amount of high-pressure steam can be supplied from the waste heat boiler to the steam turbine that drives the generator. Therefore, it can greatly contribute to an increase in the amount of power generation, and as a result, it can contribute to a reduction in CO ₂ emissions.

In the waste treatment facility according to claim 1 of the present invention or the method of using recovered heat in the waste treatment facility according to claim 2 of the present invention, the furnace air preheated by the gas air preheater is waste heat. The high-pressure steam heat generated in the boiler is recovered and preheated with a high-pressure steam air preheater.

Therefore, according to the method for using recovered heat in the waste treatment facility according to claim 1 of the present invention or the waste treatment facility according to claim 2 of the present invention, the furnace air is preheated by the high-pressure steam air preheater. Therefore, the amount of high pressure steam supplied from the waste heat boiler to the high pressure steam air preheater can be reduced. Therefore, since a lot of high-pressure steam can be supplied to the steam turbine that drives the generator, the amount of power generation does not decrease so much. On the other hand, since the furnace air supplied to the waste treatment furnace can be heated to a higher temperature, it is possible to contribute to the reduction of auxiliary fuel to the waste treatment furnace.

The usage of recovered heat in waste treatment facilities according to claim 2 of the waste treatment facility, or the present invention according to a first aspect of the present invention, the furnace air recovers heat of the low pressure steam discharged from the steam turbine The gas-type air preheater recovers the heat of the dust removal gas that has been preheated by the low pressure steam air preheater and from which the dust has been removed by the dust removal means. Next, it is preheated by this gas air preheater and supplied to the high pressure steam air preheater.

Therefore, according to the waste treatment facility or usage of recovered heat in waste treatment facilities according to claim 2 of the present invention, according to a first aspect of the present invention, or a gas type air preheater corrosion, in dust Since there is no clogging, the maintenance cost of the waste treatment facility can be reduced and the operating rate can be improved. Then, the furnace air having a temperature higher than that in the case of claim 2 or 6 can be supplied from the gas air preheater to the high pressure steam air preheater, and the high pressure steam air preheater can be supplied from the waste heat boiler. The amount of high-pressure steam supplied to can be reduced. Therefore, more high-pressure steam can be supplied to the steam turbine that drives the generator. Furthermore, since the heat of the low-pressure steam discharged from the steam turbine that has been hardly used until now is recovered, the thermal efficiency of the entire waste treatment facility is further improved.

The usage of recovered heat in waste treatment facilities according to claim 2 according wastes according to claim 1 treatment facility, or the invention of the present invention, recovering the heat of the dust removal gas dust has been removed by the dust removing means A portion of the air preheated by the gas air preheater is recirculated between the gas air preheater and the low-pressure steam air preheater via the reflux path to the furnace air supplied from the air supply source. Join. The combined furnace air is preheated by the gas air preheater and supplied to the high pressure steam air preheater.

Therefore, according to the waste treatment facility or usage of recovered heat in waste treatment facilities according to claim 2 of the present invention, according to a first aspect of the present invention, or a gas type air preheater corrosion, in dust Since there is no clogging, the maintenance cost of the waste treatment facility can be reduced and the operating rate can be improved. The furnace air having a temperature higher than that in the case of claim 3 or 7 can be supplied from the gas air preheater to the high pressure steam air preheater, and the high pressure steam air preheater can be supplied from the waste heat boiler. The amount of high-pressure steam supplied to can be further reduced. Therefore, much more high-pressure steam can be supplied to the steam turbine that drives the generator.

  Hereinafter, a waste treatment facility according to Embodiment 1 of the present invention that implements a method of using recovered heat in a waste treatment facility of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing an apparatus arrangement state of a waste treatment facility according to Embodiment 1 of the present invention.

  Reference numeral 1 shown in FIG. 1 is a waste treatment facility according to Embodiment 1 of the present invention, and the waste treatment facility 1 is configured as described later. That is, a waste treatment furnace 2 to be described later for reducing the volume of waste such as municipal waste and industrial waste is disposed. The waste treatment furnace 2 includes a gasification furnace 2a that heats and gasifies waste, and an ash in exhaust gas that is disposed on the downstream side of the gasification furnace 2a and is discharged from the gasification furnace 2a. And a melting furnace 2b for melting the dust. A waste heat boiler 3 that generates high-pressure steam at 300 ° C. or higher is disposed on the downstream side of the melting furnace 2b using the heat of the gas discharged from the melting furnace 2b. In the case of the first embodiment, as shown in FIG. 1, the melting furnace 2b and the waste heat boiler 3 are disposed at positions separated from each other. For example, the waste heat boiler 3 is An integral configuration provided on the top of the melting furnace 2b may be used, and the separation configuration is not particularly required.

  On the downstream side of the waste heat boiler 3, a temperature reduction tower 4 is provided for reducing the temperature of the exhaust gas discharged from the waste heat boiler 3 to, for example, 170 ° C. And, dust such as fly ash in the exhaust gas is captured on the downstream side of the temperature reduction tower 4 while removing HCl, SOx, dioxins in the exhaust gas after temperature reduction discharged from the temperature reduction tower 4. A bag filter (dust removing means) 5 is provided for separating the captured dust such as fly ash and discharging it out of the system. Further, on the downstream side of the bag filter 5, a reheating device 6 for reheating the dust removal exhaust gas with the steam generated in the waste heat boiler 3, decomposes and removes NOx and dioxins in the reheated dust removal exhaust gas. An induction blower 8 is provided via a catalytic reaction tower 7 and a gas air preheater 10 described later, and dust removal exhaust gas after dust removal attracted by the induction blower 8 is provided downstream of the induction blower 8. A chimney 9 is provided for releasing the air into the atmosphere.

  The gas-type air preheater 10 is supplied from an air supply source (not shown), combustion air for supplying to the gasification furnace 2a, and melting air supplied to the melting furnace 2b, that is, combustion and melting air (Furnace air) Ar is composed of a heat exchanger that recovers and preheats the heat of the dust removal gas discharged through the bag filter 5, the reheating device 6, and the catalytic reaction tower 7. Combustion and melting air Ar preheated by the gas air preheater 10 is configured to be supplied to the gasification furnace 2a and the melting furnace 2b of the waste treatment furnace 2. The high-pressure steam discharged from the waste heat boiler 3 is supplied to a steam turbine (not shown) for driving a generator (not shown) and is consumed for power generation.

  Hereinafter, the operation mode of the waste treatment facility 1 according to Embodiment 1 of the present invention will be described. That is, waste such as municipal waste and industrial waste stored in a pit (not shown) is cut out by a predetermined amount from a waste supply device (not shown) and supplied to the gasifier 2a. The waste supplied to the gasification furnace 2a is gasified by heating in the gasification furnace 2a, and together with combustible gas such as carbon monoxide, dust such as char and ash, the downstream side from the gasification furnace 2a. To the melting furnace 2b. The ash supplied to the melting furnace 2b is melted in the melting furnace 2b to become molten slag, and is discharged into a slag cooling tank (not shown) from a slag discharge port (not shown) provided in the lower part of the melting furnace 2b to be cooled. Is done.

  High-temperature exhaust gas discharged from the melting furnace 2b and containing dust such as fly ash passes through the waste heat boiler 3 and the temperature-decreasing tower 4, and is alkaline such as slaked lime for removing HCl and SOx in the exhaust gas. An adsorbent such as activated carbon for removing chemicals and dioxins is supplied to the bag filter 5 supplied to the gas inlet. Then, HCl, SOx, and dioxins in the exhaust gas supplied to the bag filter 5 are removed by an alkaline agent such as slaked lime and an adsorbent such as activated carbon, and dust such as ash is captured. Next, the dust removal gas from which HCl, SOx, dioxins and dust have been removed is reheated by the reheating device 6. Then, the reheated dust removal gas is introduced into the catalytic reaction tower 7, where NOx and dioxins in the dust removal gas are decomposed and removed, and then the gas air preheater 10 and the induction blower 8 are connected. After that, it is emitted from the chimney 9 into the atmosphere.

  In the waste treatment facility 1 according to the first embodiment of the present invention, waste such as municipal waste and industrial waste is reduced in volume through the above-described process, and detoxified by taking appropriate measures. It is processed. During the waste treatment process by the waste treatment facility 1, HCl, SOx, and dust, which are corrosive components in the bag filter 5, are contained in the gasification furnace 2 a and the melting furnace 2 b of the waste treatment furnace 2. The combustion and melting air Ar preheated by the gas air preheater 10 that recovers the heat of the dust removal gas from which NOx and dioxins have been removed by the catalytic reaction tower 7 is supplied.

  Therefore, according to the waste treatment facility 1 according to Embodiment 1 of the present invention, even if the gas-type air preheater 10 is a plate-type heat exchanger, it does not corrode with corrosive components, Further, since there is no clogging due to dust such as fly ash in the exhaust gas, the maintenance cost of the waste treatment facility 1 can be reduced and the operating rate can be improved. In addition to this, high thermal conductivity can be maintained for a long period of time, and the gas air preheater 10 can be miniaturized, which can greatly contribute to the reduction of waste disposal costs. it can.

Furthermore, the high-pressure steam generated by the waste heat boiler 3 can be supplied to a steam turbine (not shown) that drives a generator (not shown). Therefore, the thermal efficiency of the waste treatment facility 1 as a whole can be improved, and an excellent effect that it can greatly contribute to an increase in the amount of power generation can be obtained. In other words, it can contribute to CO ₂ emission reduction and can greatly contribute to the improvement of global warming.

  A waste treatment facility according to a second embodiment of the present invention that implements a method of using recovered heat in the waste treatment facility of the present invention will be described with reference to the accompanying drawings. FIG. 2 is a block diagram showing a device arrangement state of the waste treatment facility according to Embodiment 2 of the present invention. Note that the waste treatment facility according to Embodiment 2 of the present invention has a high-pressure steam air preheater added thereto, as is well understood in the comparison between FIG. 1 and FIG. Since the configuration is the same as that of the waste treatment facility according to the first embodiment, the same components are denoted by the same reference numerals, and different points are mainly described with the same names.

  That is, the waste treatment facility 1a according to the second embodiment is configured such that the combustion and melting air Ar preheated by the gas air preheater 10 is supplied to the high pressure steam air preheater 11 described later. Has been. The high-pressure steam air preheater 11 recovers a part of heat of high-pressure steam having a temperature of 300 ° C. or more supplied from the waste heat boiler 3 and melts it with the gasification furnace 2 a of the waste treatment furnace 2. Combustion and melting air supplied to the furnace 2b is constituted by a heat exchanger that preheats until reaching a preset temperature. Note that most of the high-pressure steam discharged from the waste heat boiler 3 is supplied to a steam turbine (not shown) for driving a generator (not shown) and consumed for power generation.

  According to the waste treatment facility 1 a according to the second embodiment, the combustion and melting air Ar preheated by the gas air preheater 10 is a high pressure that recovers the heat of the high-pressure steam generated in the waste heat boiler 3. After being heated by the steam air preheater 11, it is supplied to the gasification furnace 2 a and the melting furnace 2 b of the waste treatment furnace 2. Therefore, the amount of heat for preheating the combustion and melting air Ar by the high pressure steam air preheater 11 can be reduced, and the amount of high pressure steam supplied from the waste heat boiler 3 to the high pressure steam air preheater 11 can be reduced. Can be reduced. Therefore, since a lot of high-pressure steam can be supplied to the steam turbine that drives the generator, the amount of power generation does not decrease so much. On the other hand, since the combustion and melting air Ar supplied to the waste treatment furnace 2 can be heated to a higher temperature, it is possible to contribute to a reduction in auxiliary fuel to the waste treatment furnace 2.

  Of course, according to the waste treatment facility 1a according to the second embodiment of the present invention, the gas air preheater 10 is a plate-type heat exchanger as in the waste treatment facility 1 according to the first embodiment. However, since it does not corrode with corrosive components and is not clogged with dust such as fly ash in the exhaust gas, the maintenance cost of the waste treatment facility 1a can be reduced and the operation rate can be reduced. Improvement is possible. In addition to this, high thermal conductivity can be maintained for a long period of time, and the gas air preheater 10 can be miniaturized, which can greatly contribute to the reduction of waste disposal costs. it can.

  A waste treatment facility according to a third embodiment of the present invention that implements a method of using recovered heat in the waste treatment facility of the present invention will be described with reference to the accompanying drawings. FIG. 3 is a block diagram showing a device arrangement state of the waste treatment facility according to Embodiment 3 of the present invention. The difference between the waste treatment facility according to Embodiment 3 of the present invention and the waste treatment facility according to Embodiment 2 is that a low-pressure steam air preheater is added. Since the configuration is the same as that of the waste treatment facility according to the second embodiment, the same components are denoted by the same reference numerals, and different points are mainly described with the same names.

  That is, the waste treatment facility 1b according to the third embodiment of the present invention includes a waste treatment facility 1a according to the second embodiment and an upstream side of the gas air preheater 10 of the waste treatment facility 1a. That is, a low-pressure steam air preheater 12 described later is disposed between the gas air preheater 10 and an unillustrated combustion / melting air supply source. The low-pressure steam air preheater 12 collects heat of low-pressure steam discharged from a steam turbine (not shown) that drives a generator (not shown), thereby supplying combustion and melting air to the gas air preheater 10. It consists of a heat exchanger that preheats Ar.

In the case of the waste treatment facility 1b according to Embodiment 3 of the present invention, the combustion and melting air Ar is a low pressure steam air preheater 12 that recovers heat of low pressure steam discharged from a steam turbine (not shown); Preheated by a gas air preheater 10 that recovers the heat of the dust removal gas.
That is, the combustion and melting air Ar is preheated by the low pressure steam air preheater 12 that recovers the heat of the low pressure steam discharged from a steam turbine (not shown) and supplied to the gas air preheater 10. It is further preheated by the air preheater 10 and supplied to the high-pressure steam air preheater 11.

Therefore, according to the waste treatment facility 1b according to the third embodiment of the present invention, as in the case of the waste treatment facility 1 according to the first embodiment, the gas air preheater 10 corrodes with a corrosive component. Therefore, it is possible to reduce the maintenance cost and improve the operation rate of the waste treatment facility 1b. Then, higher temperature combustion and melting air can be supplied from the gas air preheater 10 to the high pressure steam air preheater 11, and the high pressure steam supplied from the waste heat boiler 3 to the high pressure steam air preheater 11 can be supplied. Since the supply amount can be reduced, more high-pressure steam can be supplied to the steam turbine that drives the generator. Furthermore, since the heat of the low-pressure steam exhausted from the steam turbine that has been rarely used until now is recovered, the thermal efficiency of the entire waste treatment facility can be further improved and further contribute to CO ₂ emission reduction. It can make a great contribution to the improvement of global warming.

  A waste treatment facility according to a fourth embodiment of the present invention that implements a method of using recovered heat in the waste treatment facility of the present invention will be described with reference to the accompanying drawings. FIG. 4 is a block diagram showing an apparatus arrangement state of the waste treatment facility according to Embodiment 4 of the present invention. Note that the waste treatment facility according to the fourth embodiment of the present invention differs from the waste treatment facility according to the third embodiment in that the preheated combustion and melting air flows out from the gas air preheater. Is partly configured to be recirculated to the combustion and melting air inlet side of the gas-type air preheater, and the rest is the same as the waste treatment facility according to the third embodiment. The same components are denoted by the same reference numerals, and different points will be described with the same names.

  That is, the waste treatment facility 1c according to Embodiment 4 of the present invention includes the gas air preheater 10 and the high pressure steam air preheater 11, and the gas air preheater 10 and the low pressure steam air. The preheaters 12 are connected to each other via a reflux path 13 that recirculates a part of combustion and melting air preheated by the gas air preheater 10. An induction fan (not shown) is interposed in the middle of the reflux path 13, and the induction fan is configured to be driven by operating a switch (not shown).

  In the case of the waste treatment facility 1c according to Embodiment 4 of the present invention, for combustion and melting preheated by the gas air preheater 10 that recovers the heat of the dust removal gas from which dust has been removed by the bag filter 5. A part of the air Ar for recirculation, which is partly recirculated between the gas-type air preheater 10 and the low-pressure steam air preheater 12 via the recirculation path 13 and recirculated, It is preheated again by the gas air preheater 10 and supplied to the high pressure steam air preheater 11.

  Therefore, according to the waste treatment facility 1c according to the fourth embodiment of the present invention, as in the case of the waste treatment facilities 1, 1a, 1b according to the first to third embodiments, the gas air preheater 10 described above. Therefore, the maintenance cost of the waste treatment facility 1c can be reduced and the operating rate can be improved. Further, higher temperature combustion and melting air can be supplied from the gas air preheater 10 to the high pressure steam air preheater 11, and the high pressure steam supplied from the waste heat boiler 3 to the high pressure steam air preheater 11. Therefore, a larger amount of high-pressure steam can be supplied to a steam turbine (not shown) that drives a generator (not shown).

  By the way, the outlet side of the high-pressure steam air preheater 11 and the reflux path 13 are communicated with each other by a second reflux path 14, and a part of combustion and melting air flowing out from the high-pressure steam air preheater 11 is refluxed. A configuration may be adopted in which the gas-type air preheater 10 is refluxed through the passage 13. With such a configuration, the surface temperature of the heat transfer tube of the gas air preheater 10 can be increased by increasing the air temperature at the inlet of the gas air preheater 10, so that low temperature corrosion due to acid gas is prevented. An excellent effect that it can be reduced can be obtained.

  Examples according to the waste treatment facility of the present invention will be described below. In this case, a waste treatment facility using only the high pressure steam air preheater 11 for preheating the combustion and melting air supplied to the gasification furnace 2a and the melting furnace 2b (hereinafter referred to as a comparative example) The generator in the case of the waste treatment facility 1a according to the second embodiment for supplying combustion and melting air preheated by the gas air preheater 10 to the high pressure steam air preheater 11 (hereinafter referred to as this example) This is a comparison of the amount of power generated by the calculation.

According to the calculation result, since the supply amount of the high-pressure steam supplied to the high-pressure steam air preheater 11 is small, and the excess high-pressure steam can be supplied to the steam turbine by the reduced supply amount, the generator It has been found that the amount of power generated by increases by about 1%. In this case, the combustion of the gas air preheater 10, the inlet temperature of the melting air, the outlet temperature, and the conditions are as follows. The outlet temperature of the high pressure steam air preheater 11 is as follows.
(1) Gas air preheater Inlet temperature: 20 ° C
Outlet temperature: 80 ° C (+ 60 ° C)
(2) High-pressure steam air preheater Outlet temperature: 200 ° C (+ 120 ° C)

  In the waste treatment facility according to Embodiments 1 to 4 described above, the case where the waste treatment furnace is configured by a gasification furnace and a melting furnace has been described as an example. However, the present invention is not limited thereto, and only the incinerator that incinerates the waste using the technical idea of the present invention as the waste treatment furnace, and the waste treatment that includes only the melting furnace that melts the incinerated ash incinerated in the incinerator. It can also be applied to equipment. In the waste treatment facility according to the first to fourth embodiments, the gas air preheater 10 removes HCl and SOx in the exhaust gas by the bag filter 5 and dust such as fly ash. As an example, the case where the exhaust gas is disposed downstream of the catalytic reaction tower 7 that decomposes and removes NOx and dioxins in the exhaust gas has been described. However, even if the gas-type air preheater 10 is disposed on the downstream side of the bag filter 5, the same effect as the waste treatment facility according to the first to fourth embodiments can be obtained.

  Therefore, the waste treatment facility according to the first to fourth embodiments is merely a specific example of the present invention, and design changes and the like can be freely made without departing from the technical idea of the present invention. The scope of application of the technical idea is not limited to the form of the waste treatment facility according to the first to fourth embodiments.

It is a block diagram which shows the apparatus arrangement | positioning state of the waste disposal facility which concerns on Embodiment 1 of this invention. It is a block diagram which shows the apparatus arrangement | positioning state of the waste disposal facility which concerns on Embodiment 2 of this invention. It is a block diagram which shows the apparatus arrangement | positioning state of the waste disposal facility which concerns on Embodiment 3 of this invention. It is a block diagram which shows the apparatus arrangement | positioning state of the waste disposal facility which concerns on Embodiment 4 of this invention. It is a figure which concerns on the prior art example 1 and shows the arrangement | sequence of the waste gas treatment equipment of a waste incinerator. FIG. 6A is a flowchart showing a method for preheating air, and FIG. 6B is a cross-sectional view of a chimney according to Conventional Example 2. FIG. 6 is a process diagram of an exhaust gas treatment method according to Conventional Example 3;

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a, 1b, 1c ... Waste processing equipment 2 ... Waste processing furnace, 2a ... Gasification furnace, 2b ... Melting furnace 3 ... Waste heat boiler 4 ... Temperature-reduction tower 5 ... Bag filter 6 ... Reheating apparatus 7 ... Catalytic reaction tower 8 ... Induction fan 9 ... Chimney 10 ... Gas air preheater 11 ... High pressure steam air preheater 12 ... Low pressure steam air preheater 13 ... Recirculation path 14 ... Second recirculation path Ar ... Air for combustion and melting

Claims (2)

A waste treatment furnace that reduces the volume of waste such as municipal waste and industrial waste, a waste heat boiler that generates high-pressure steam using the heat of the exhaust gas discharged from the waste treatment furnace, and this waste A dust removing unit that captures and removes dust such as fly ash in the exhaust gas flowing out of the heat boiler, an induction blower that sends the dust removal gas from which dust is removed by the dust removing unit to the chimney, and the waste heat boiler In a waste treatment facility comprising a steam turbine that drives a generator using the generated high-pressure steam, the heat of the dust removal gas is recovered between the dust removal means and the chimney to dispose of the waste. A gas-type air preheater that preheats the furnace air supplied to the material processing furnace is installed,
High pressure steam that preheats the furnace air preheated by the gas air preheater using the high pressure steam generated by the waste heat boiler between the gas air preheater and the waste treatment furnace. Type air preheater,
A low pressure for recovering and preheating the furnace air supplied to the gas air preheater by recovering the heat of the low pressure steam discharged from the steam turbine between the gas air preheater and the supply source of the furnace air. A steam air preheater is installed,
A furnace preheated by the gas air preheater between the gas air preheater and the high pressure steam air preheater and between the gas air preheater and the low pressure steam air preheater. Communicating with a reflux path that circulates part of the working air,
A part of the furnace air preheated by the high pressure steam air preheater is recirculated between the high pressure steam air preheater and the waste treatment furnace and the reflux path through the reflux path . A waste treatment facility characterized in that it communicates with the second reflux path. A waste treatment furnace that reduces the volume of waste such as municipal waste and industrial waste, a waste heat boiler that generates high-pressure steam using the heat of the exhaust gas discharged from the waste treatment furnace, and this waste A dust removing unit that captures and removes dust such as fly ash in the exhaust gas flowing out of the heat boiler, an induction blower that sends the dust removal gas from which dust is removed by the dust removing unit to the chimney, and the waste heat boiler In a method for using recovered heat in a waste treatment facility including a steam turbine that drives a generator using generated high-pressure steam, the heat of the dust removal gas is recovered by a gas-type air preheater and the discarded Preheat furnace air to be supplied to the material processing furnace,
When supplying the furnace air preheated by the gas air preheater to the waste treatment furnace, preheat by a high pressure steam air preheater using heat of high pressure steam generated by the waste heat boiler,
The furnace air to be supplied to the gas air preheater is recovered by the low pressure steam air preheater and preheated from the low pressure steam discharged from the steam turbine,
A part of the furnace air preheated by the gas air preheater is recirculated between the gas air preheater and the low pressure steam air preheater via a reflux path, and the low pressure steam air preheat is performed. Combined with the furnace air preheated by the vessel,
Part of the furnace air preheated by the high pressure steam air preheater is recirculated between the gas air preheater and the low pressure steam air preheater via the second recirculation path and the recirculation path. A method for using recovered heat in a waste treatment facility, wherein the furnace air is preheated by the low-pressure steam air preheater .

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