JP2012017923A - Operation method of municipal waste incineration plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change exhaust gas temperature of an outlet of an economizer to a temperature determined by a conventional device and its result or higher to enhance power generation efficiency.SOLUTION: In an operation method of a municipal waste incineration plant in which an exhaust gas G exhausted from an incinerator 1 passes through a boiler 2, the economizer 3, a temperature reducing tower 4 and a bag filter 5 in this order to perform heat recovery, temperature adjustment and purification treatment of the exhaust gas G, steam generated from the boiler 2 is introduced to a power generation facility 10 to perform power generation and recovery water obtained by condensing exhaust steam S' exhausted from a steam turbine 10a of the power generation facility 10 is heated and deaerated by a deaerator 13 as boiler supply water W and then supplied to the economizer 3 and the boiler 2, on operation of deaerator 13, the temperature of the exhaust gas G on the outlet side of the economizer 3 is used as an index, the pressure control of the deaerator 13 is performed on the basis of the temperature of the exhaust gas G on the outlet side of the economizer 3 and temperature of the boiler supply water W supplied to the economizer 3 is controlled.

Description

  The present invention is directed to boilers, economizers, temperature reduction towers and bugs that emit exhaust gas from incinerators that incinerate municipal waste such as paper, cocoons, textiles, wood / bamboo, and plastics from homes and offices. Exhaust steam exhausted from the steam turbine is passed through the filter in order to recover heat, adjust the temperature, and purify the exhaust gas. Also, the steam generated in the boiler is led to a power generation facility consisting of a steam turbine and a generator. Condensate water obtained by condensing water is heated and degassed by a deaerator as boiler feed water, and then supplied to the economizer and boiler. The exhaust gas temperature is determined by the temperature of the conventional bag filter or other device (for example, the temperature determined by the gas passing temperature of the exhaust gas bag filter or (Temperature determined by spraying amount of dewarmed water in the tower), the power generation efficiency can be improved, and even if the amount of dewarmed water necessary for exhaust gas is sprayed in the dewarming tower The present invention relates to a method for operating a municipal waste incineration plant that can maintain an exhaust gas temperature at an entrance of a bag filter at an appropriate temperature.

  Conventionally, as municipal waste incineration plants, for example, in Japanese Patent Application Laid-Open No. 2004-309079 (Patent Document 1), Japanese Patent Application Laid-Open No. 2009-162452 (Patent Document 2), Japanese Patent Application Laid-Open No. 2010-048456 (Patent Document 3). What is disclosed is known.

  FIG. 3 is a block diagram showing an example of a conventional municipal waste incineration plant. The municipal waste incineration plant includes an incinerator 100, a boiler 101, a power generation facility 102, an economizer 103, a temperature reducing tower 104, a bag filter 105, and a chimney 106. Etc.

In the municipal waste incineration plant, the high-temperature exhaust gas discharged from the incinerator 100 is guided to the boiler 101 and the economizer 103 to recover heat from the exhaust gas, and the heat-recovered exhaust gas is guided to the temperature reducing tower 104. After the temperature is adjusted, the air is guided to the bag filter 105. After the dust and acid gas in the exhaust gas are removed by the bag filter 105, the cleaned exhaust gas is discharged from the chimney 106 to the atmosphere.
Further, steam generated in the boiler 101 is led to a power generation facility 102 including a steam turbine and a generator to generate power.

By the way, in the planning and design of the municipal waste incineration plant, the thermal energy of the exhaust gas is recovered as much as possible by the boiler 101 and the economizer 103 to increase the power generation efficiency.
At that time, for example, the exhaust gas temperature on the outlet side of the economizer 103 is determined by the gas passing temperature (for example, 160 ° C.) in the bag filter 105. This is because the bag filter 105 needs to take into account its heat resistance limit and is used in a temperature range in which the acid gas removal efficiency is high.

In addition, in the municipal waste incineration plant, there are many factors affecting the quality of municipal waste due to seasonal and secular changes in municipal waste. Therefore, municipal waste is heated from the amount of heat generated during combustion to low-quality waste (low-heat generated waste), high The waste is classified into high-quality waste (high-heat generation waste) and standard waste (low-quality waste heat generation waste and high-quality waste heat generation intermediate waste), and planning and design are performed based on these. It is customary.
Table 1 below shows an example of the exhaust gas temperature on the outlet side of the economizer 103 in each municipal waste quality.

  As is clear from Table 1, there is a difference in the exhaust gas temperature on the outlet side of the economizer 103 depending on the waste quality. Normally, the specifications of the economizer 103 are determined so that the necessary heat recovery can be performed with the standard waste, so the gas temperature at the outlet of the economizer 103 becomes high in high quality waste with a large heat input to the boiler 101, and the heat input With low-quality waste with little amount, the gas temperature at the outlet of the economizer 103 becomes low.

Furthermore, in the planning and design of municipal waste incineration plants, wastewater discharged from the plant (waste pit wastewater that oozes out from the waste pit, ash discharge wastewater that cools the incineration ash, blower wastewater from the boiler, and plant cleaning) In many cases, wastewater closed conditions are required to treat wastewater, etc.) in a wastewater treatment facility attached to the plant, reuse this wastewater treatment within the plant, and prevent it from being discharged outside the plant.
At this time, the wastewater treated water is used as the temperature-reduced water of the temperature-reduction tower 104 for reducing the exhaust gas temperature on the outlet side of the economizer 103 to a temperature at which gas can be passed through the bag filter 105.

The amount of the temperature-reduced water includes a minimum amount that must be sprayed into the temperature-reduction tower 104 under the drainage closed condition.
Therefore, when the wastewater closed condition is adopted in the municipal waste incineration plant, the exhaust gas temperature on the outlet side of the economizer 103 is different from the case where the wastewater closed condition is not adopted.

That is, when the wastewater closed condition is adopted in the municipal waste incineration plant, there is an amount of sprayed water that has to be sprayed in the temperature reducing tower 104. Therefore, the exhaust gas temperature on the outlet side of the economizer 103 is set when there is no drainage closed condition. It must be higher compared.
Table 2 below shows an example of the exhaust gas temperature on the outlet side of the economizer 103 in each municipal waste quality when the drainage closed condition is given.

When the wastewater closed condition is adopted in the municipal waste incineration plant, the design of the economizer 103 determines its specification with low-quality waste with a small amount of exhaust gas and a low outlet gas temperature. That is, the design equipment (exhaust gas temperature 210 ° C.) of the economizer 103 that reduces the temperature of the low-quality waste to the exhaust gas temperature at which the amount of water reduced in the temperature reduction tower 104 becomes the required amount of spray water is performed.
At this time, the exhaust gas temperature on the outlet side of the economizer 103 in the standard waste is as high as 225 ° C. as shown in Table 2, and therefore the exhaust gas temperature of 225 ° C. in the temperature reducing tower 104 with only wastewater treated water. Cannot be lowered to a temperature at which gas can be passed through the bag filter 105.
Therefore, when the wastewater closed condition is adopted in the municipal waste incineration plant, the temperature of the exhaust gas is reduced not only in wastewater treatment water but also in fresh water using high-temperature waste and standard waste in the temperature reduction tower 104. .

  In order to recover heat, it is desirable to lower the exhaust gas temperature on the outlet side of the economizer 103 as much as possible during standard waste, which is frequently generated (for example, 220 ° C.). In this case, the outlet of the economizer 103 is used during low-quality waste. There is a problem that the temperature of the exhaust gas on the side is too low, the amount of temperature-reduced water in the temperature-reduction tower 104 is less than the required spray amount, and the drainage closed condition cannot be achieved.

In recent years, municipal waste incineration plants have been required to increase the efficiency of waste power generation in order to further promote the effective use of energy generated by the combustion of waste for the purpose of further countermeasures against global warming. Yes.
In order to perform waste power generation with high efficiency, it is necessary to lower the exhaust gas temperature on the outlet side of the economizer 103 to reduce the amount of heat taken out of the exhaust gas from the boiler 101 and the economizer 103, and to increase the amount of heat absorbed by the boiler 101. .

  As described above, in order to achieve the drainage closed condition, the exhaust gas temperature on the outlet side of the economizer 103 needs to be raised to some extent, whereas in order to increase the efficiency of waste power generation, the outlet side of the economizer 103 The exhaust gas temperature must be lowered, resulting in contradictory problems.

In order to solve such a problem, the following methods (1) and (2) are conventionally employed.
(1) Reduce the amount of generated waste water from the plant and reduce the amount of water used in the temperature reduction tower.
(2) Bypassing a part of the exhaust gas that passes through the economizer and guiding it between the economizer and the cooling tower, it prevents the exhaust gas temperature from being lowered during low-quality waste, which is the rate-limiting condition of the drainage closed, and a predetermined amount of reduced water (Eco-bypass).

However, with regard to the method (1) described above, even if the amount of wastewater generated is suppressed, the effect is limited, and the current situation is that it does not lead to a reduction in the amount of temperature-reduced water so that the economizer can sufficiently recover heat. It is.
In the method (2), the gas flow rate between the economizer and the bypass route is controlled according to the waste quality, and the exhaust gas temperature at the exit side of the economizer is set to a predetermined temperature. It is necessary to add a new one, and in order to prevent low temperature corrosion of the duct forming the bypass route, it is necessary to always pass a part of the exhaust gas to the bypass route or to add a heater or other equipment, and an appropriate economizer It becomes difficult to design.

JP 2004-309079 A JP 2009-162452 A JP 2010-048456 A

  The present invention has been made in view of such problems. The purpose of the present invention is to determine the temperature of exhaust gas discharged from an economizer by design points (e.g., low-quality garbage) such as an economizer, a temperature reducing tower, and a bag filter. In the equipment designed in (4), other waste quality (for example, at the time of standard waste) is changed beyond the temperature determined by the process, so that the power generation efficiency can be improved and the temperature reduction tower To provide a method for operating a municipal waste incineration plant that can maintain the temperature of the exhaust gas at the bag filter inlet at an appropriate temperature even when sprayed with the amount of reduced water necessary to achieve the closed wastewater condition. is there.

  In order to achieve the above object, the invention of claim 1 of the present invention is directed to recovering heat of exhaust gas through exhaust gas discharged from an incinerator for incineration of municipal waste in the order of a boiler, an economizer, a temperature reducing tower, and a bag filter. It is obtained by adjusting the temperature of the exhaust gas and purifying the exhaust gas, and also by condensing the exhaust steam discharged from the steam turbine while directing the steam generated in the boiler to the power generation facility consisting of the steam turbine and generator. In the operation method of a municipal waste incineration plant where the condensate is heated and degassed by a deaerator as boiler feed water and then supplied to the economizer and boiler, the economizer outlet is operated when operating the deaerator. Boiler water supplied to the economizer by controlling the pressure of the deaerator based on the exhaust gas temperature on the outlet side of the economizer And controlling the temperature, the exhaust gas temperature at the outlet side of the economizer, is characterized in that so as to vary over temperature determined by the conventional apparatus consequences.

  The invention of claim 2 of the present invention is the invention of claim 1, wherein the exhaust gas temperature at the outlet side of the economizer is always detected by a temperature detector, and the exhaust gas temperature at the outlet side of the economizer is below a predetermined temperature. When the set pressure of the deaerator is increased to raise the temperature of boiler feed water supplied to the economizer to reduce the amount of heat exchange in the economizer, and the exhaust gas temperature on the economizer outlet side exceeds the specified temperature Is characterized in that the set pressure of the deaerator is lowered to lower the temperature of boiler feed water supplied to the economizer to increase the amount of heat exchange in the economizer.

  According to the third aspect of the present invention, exhaust gas discharged from an incinerator for incinerating municipal waste is passed through a boiler, an economizer, a temperature reducing tower, and a bag filter in this order to recover heat of the exhaust gas, adjust the temperature of the exhaust gas, and purify the exhaust gas. In addition, the steam generated in the boiler is led to a power generation facility consisting of a steam turbine and a generator to generate power, and the condensate obtained by condensing the exhaust steam discharged from the steam turbine is removed as boiler feed water. In the operation method of the municipal waste incineration plant, which is heated and degassed by the ventilator and then supplied to the economizer and boiler, when operating the deaerator, the amount of dewarmed water used in the cooler tower is an index The temperature of the boiler feed water supplied to the economizer is controlled by controlling the pressure of the deaerator based on the amount of water used in the temperature reducing tower, and the exhaust gas at the outlet side of the economizer is controlled. The temperature, is characterized in that so as to vary over temperature determined by the conventional apparatus consequences.

  In the invention of claim 4 of the present invention, in the invention of claim 3, when the amount of water to be reduced used in the temperature reducing tower is below a predetermined amount, the set pressure of the deaerator is increased and supplied to the economizer. Increase the boiler feed water temperature to reduce the amount of heat exchange in the economizer, and if the amount of water to be used in the temperature reduction tower exceeds the specified amount, reduce the set pressure of the deaerator to the economizer It is characterized in that the amount of heat exchange in the economizer is increased by lowering the temperature of the boiler feed water supplied.

  According to the fifth aspect of the present invention, exhaust gas discharged from an incinerator for incinerating municipal waste is passed through a boiler, an economizer, a temperature reducing tower, and a bag filter in this order to recover heat of the exhaust gas, adjust the temperature of the exhaust gas, and purify the exhaust gas. In addition, the steam generated in the boiler is led to a power generation facility consisting of a steam turbine and a generator to generate power, and the condensate obtained by condensing the exhaust steam discharged from the steam turbine is removed as boiler feed water. A method for operating a municipal waste incineration plant in which the boiler feed water is heated and degassed by an air vent, and then temperature controlled by a feed water heater provided on the outlet side of the deaerator before being supplied to the economizer and boiler. In operating the feed water heater, the exhaust gas temperature on the exit side of the economizer is used as an index, and the feed water heater is based on the exhaust gas temperature on the exit side of the economizer Controlling the temperature of the boiler feed water supplied to the economizer by performing a driving operation, the exhaust gas temperature at the outlet side of the economizer, is characterized in that so as to vary over temperature determined by the conventional apparatus consequences.

  The invention of claim 6 of the present invention is the invention of claim 5, wherein the exhaust gas temperature on the outlet side of the economizer is always detected by a temperature detector, and the exhaust gas temperature on the outlet side of the economizer is below a predetermined temperature. Increases the heat exchange amount of the feed water heater and raises the temperature of boiler feed water supplied to the economizer to reduce the heat exchange amount in the economizer, and the exhaust gas temperature on the outlet side of the economizer exceeds the predetermined temperature In this case, the heat exchange amount in the economizer is increased by lowering the temperature of boiler feed water supplied to the economizer with the exchange heat amount of the feed water heater being reduced or reduced to zero.

  According to the seventh aspect of the present invention, exhaust gas discharged from an incinerator for incinerating municipal waste is passed through a boiler, an economizer, a temperature reducing tower, and a bag filter in this order to recover heat of the exhaust gas, adjust the temperature of the exhaust gas, and purify the exhaust gas. In addition, the steam generated in the boiler is led to a power generation facility consisting of a steam turbine and a generator to generate power, and the condensate obtained by condensing the exhaust steam discharged from the steam turbine is removed as boiler feed water. A method for operating a municipal waste incineration plant in which the boiler feed water is heated and degassed by an air vent, and then temperature controlled by a feed water heater provided on the outlet side of the deaerator before being supplied to the economizer and boiler. In operating the feed water heater, the amount of water used in the temperature reduction tower is used as an index, and the water heater is operated based on the amount of water used in the temperature reduction tower. Controlling the temperature of the boiler feed water supplied to the economizer, the exhaust gas temperature at the outlet side of the economizer, is characterized in that so as to vary over temperature determined by the conventional apparatus consequences.

  According to the eighth aspect of the present invention, in the seventh aspect of the present invention, when the amount of the temperature-reduced water used in the temperature-decreasing tower is less than a predetermined amount, the exchange heat amount of the feed water heater is increased and supplied to the economizer. The temperature of the boiler feed water is increased to reduce the amount of heat exchange in the economizer, and if the amount of reduced water used in the temperature reduction tower exceeds the predetermined amount, the amount of heat exchanged in the feed water heater is reduced. It is characterized in that the amount of heat exchange in the economizer is increased by lowering the temperature of boiler feed water supplied to the economizer.

  The invention of claim 9 of the present invention is the temperature reducing tower according to claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, claim 7 or claim 8. Wastewater closed water that uses wastewater treated water discharged from municipal waste incineration plant as the temperature-reduced water sprayed in, and uses all of the wastewater treated water in the temperature-decreasing tower so that the wastewater treated water is not discharged outside the plant. It is characterized by adopting conditions.

  The invention of claim 1 of the present invention is a method for operating a municipal waste incineration plant equipped with an incinerator, boiler, economizer, temperature reducing tower, bag filter, power generation equipment, deaerator, etc., and operating the deaerator. In doing so, the temperature of the exhaust gas at the outlet side of the economizer is used as an index, the pressure of the deaerator is controlled based on the exhaust gas temperature at the outlet side of the economizer, and the temperature of the boiler feed water supplied to the economizer is controlled. Because the exhaust gas temperature is changed to a temperature that is determined by the conventional system, the exhaust gas temperature on the exit side of the economizer, which is required for low-quality municipal waste, is determined. Power generation efficiency is sometimes reduced by lowering the exhaust gas temperature at the outlet side of the economizer, rather than the exhaust gas temperature at the outlet side of the economizer, which is sometimes determined by the conventional system. It is possible to improve the.

  In the invention of claim 2 of the present invention, the exhaust gas temperature on the outlet side of the economizer is always detected by a temperature detector, and when the exhaust gas temperature on the outlet side of the economizer is lower than a predetermined temperature, the pressure of the deaerator is increased. The temperature of the exhaust gas supplied to the economizer is increased to reduce the amount of heat exchange in the economizer. The required gas temperature in the bag filter can be kept below, and if the exhaust gas temperature on the outlet side of the economizer exceeds the specified temperature, the pressure of the deaerator is lowered and supplied to the economizer Since the temperature of boiler feed water is lowered and the amount of heat exchange in the economizer is increased, the amount of power generation can be improved.

  The invention of claim 3 of the present invention is a method for operating a municipal waste incineration plant equipped with an incinerator, boiler, economizer, temperature reducing tower, bag filter, power generation equipment, deaerator, etc. In doing so, the temperature of the boiler water supplied to the economizer is controlled by controlling the pressure of the deaerator based on the amount of water used in the temperature reduction tower as an index, Since the exhaust gas temperature on the outlet side of the economizer is changed to a temperature determined by the state of the conventional device, the power generation efficiency can be improved as in the first aspect of the invention.

  According to the invention of claim 4 of the present invention, when the amount of water to be reduced used in the temperature reducing tower is below a predetermined amount, the pressure of the deaerator is increased to increase the temperature of boiler feed water supplied to the economizer, and the economizer The amount of heat exchange in the bag filter is reduced, so that the temperature of the exhaust gas is reduced to the required gas in the bag filter even if sprayed with the amount of reduced temperature water required for the exhaust gas in the temperature reduction tower as in the invention of claim 2. The temperature of the boiler feed water supplied to the economizer can be lowered by reducing the pressure of the deaerator when the amount of water used in the temperature reduction tower exceeds the specified amount. Since the amount of heat exchange in the economizer is increased, the power generation amount can be improved.

  The invention of claim 5 of the present invention is a method for operating a municipal waste incineration plant comprising an incinerator, a boiler, an economizer, a temperature reducing tower, a bag filter, a power generation facility, a deaerator, a feed water heater and the like. When operating the heater, the exhaust gas temperature at the outlet side of the economizer is used as an index, the temperature of the boiler feed water supplied to the economizer is controlled by operating the feed water heater based on the exhaust gas temperature at the outlet side of the economizer, Since the exhaust gas temperature on the outlet side of the economizer is changed to a temperature determined by the state of the conventional device, the power generation efficiency can be improved as in the first aspect of the invention.

  In the invention of claim 6 of the present invention, the exhaust gas temperature on the outlet side of the economizer is always detected by a temperature detector, and when the exhaust gas temperature on the outlet side of the economizer is lower than a predetermined temperature, the exchange heat amount of the feed water heater is set. Since the boiler feed water temperature supplied to the economizer is increased to reduce the amount of heat exchange in the economizer, even if the amount of dewarmed water required for the exhaust gas is sprayed in the temperature reduction tower, The temperature can be kept below the required gas temperature in the bag filter, and if the exhaust gas temperature at the outlet side of the economizer exceeds the predetermined temperature, the heat exchange amount of the feed water heater is made small or zero Since the temperature of the boiler feed water supplied to the economizer is lowered to increase the amount of heat exchange in the economizer, the power generation amount can be improved.

  The invention of claim 7 of the present invention is a method for operating a municipal waste incineration plant comprising an incinerator, a boiler, an economizer, a temperature reducing tower, a bag filter, a power generation facility, a deaerator, a feed water heater, etc. The temperature of boiler feed water supplied to the economizer by operating the feed water heater based on the amount of temperature-reduced water used in the temperature-reduction tower, using the temperature-reduced water amount used in the temperature-reduction tower as an index when operating the heater Thus, the exhaust gas temperature on the outlet side of the economizer is changed to a temperature determined by the behavior of the conventional device or more, so that the power generation efficiency can be improved as in the first aspect of the invention.

  The invention of claim 8 of the present invention increases the temperature of boiler feed water supplied to the economizer by increasing the amount of heat exchanged in the feed water heater when the amount of dewarmed water used in the temperature reducing tower is below a predetermined amount. Because the amount of heat exchange in the economizer is reduced, the temperature of the exhaust gas does not fall below the required gas temperature in the bag filter even if sprayed with the amount of reduced water required for the exhaust gas in the temperature reduction tower. If the amount of water used in the cooling tower exceeds the specified amount, the temperature of boiler feed water supplied to the economizer can be reduced by reducing the exchange heat amount of the feed water heater. Since the amount of heat exchange is increased, the amount of power generation can be improved.

  The invention of claim 9 of the present invention employs closed drainage conditions in which all wastewater treated water is used as temperature-reduced water in the temperature-reducing tower, so that it is reduced in the temperature-reduced tower during standard waste and high-quality waste. When the amount of warm water exceeds the amount of wastewater treated water and the shortage needs to be replenished with fresh water, reduce the pressure of the deaerator during standard waste or high-quality waste, or reduce the heat exchange of the feed water heater As a result, the amount of the temperature-reduced water can be reduced. As a result, the amount of fresh water replenished water can be reduced, and the power generation efficiency can be improved as in the first aspect of the invention.

It is a schematic system diagram which shows an example of the municipal waste incineration plant which enforces the method of this invention. It is a block diagram which shows an example of the municipal waste incineration plant which implements the other method of this invention. It is a block diagram which shows an example of the conventional municipal waste incineration plant.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic system diagram showing an example of a municipal waste incineration plant that implements the method of the present invention. The municipal waste incineration plant is an incinerator 1 (for example, a stoker type) that incinerates municipal waste from homes and business establishments. An incinerator), a boiler 2 for recovering heat from the high-temperature exhaust gas G generated in the incinerator 1, an economizer 3 for further recovering heat of the exhaust gas G discharged from the boiler 2, and an exhaust gas G that has passed through the economizer 3 A temperature reducing tower 4 that cools the exhaust gas G by spraying the temperature-reduced water (waste water treatment water), a bag filter 5 that removes dust and acid gas in the exhaust gas G, and an induced draft that induces the exhaust gas G in the incinerator 1 Machine 7, chimney 8 that discharges clean exhaust gas G into the atmosphere, superheater 9 that superheats steam generated in boiler 2, and steam turbine that is driven by superheated steam S from superheater 9 to generate electricity 10 And a power generation facility 10 including a generator 10b, a condenser 11 for condensing exhaust steam S ′ discharged from the steam turbine 10a, a condensate tank 12 for storing condensate from the condenser 11, and a condenser The condensate from the water tank 12 is heated and degassed, and is composed of an economizer 3 and a deaerator 13 that supplies the boiler 2 as boiler feed water W. When the deaerator 13 is operated, the economizer 3 The temperature of the boiler feed water W supplied to the economizer 3 is controlled by controlling the pressure of the deaerator 13 based on the exhaust gas G temperature on the outlet side, based on the exhaust gas G temperature on the outlet side of the economizer 3. The exhaust gas G temperature at the outlet side is determined by the temperature of the conventional bag filter 5 or the like (for example, the temperature determined by the gas passing temperature of the exhaust gas G through the bag filter 5 or a temperature reducing tower). It is changed to the temperature) or more as determined by the spray amount of reduced hot water is obtained by such improved such power generation amount.

That is, the municipal waste incineration plant is supplied to the temperature detector 14 that constantly detects the exhaust gas G temperature on the outlet side of the economizer 3 and the extracted steam S ″ from the steam turbine 10a (or the steam turbine 10a although not shown). A steam supply pipe 15 for supplying a portion of the superheated steam S extracted to the deaerator 13, and an extracted steam S ″ (or superheater) provided in the steam supply pipe 15 and supplied to the deaerator 13. The steam control valve 16 for controlling the supply amount of steam (a part of the steam S withdrawn) and the pressure in the deaerator 13 are detected, and the steam is detected based on the detection signal and the detection signal from the temperature detector 14. And a pressure controller 17 for controlling the pressure of the deaerator 13 by controlling the amount control valve 16. The exhaust gas G temperature on the outlet side of the economizer 3 is always detected by the temperature detector 14, and the outlet of the economizer 3 is Exhaust gas G temperature The pressure control of the deaerator 13 is performed based on the above, the temperature of the boiler feed water W supplied to the economizer 3 is controlled by the pressure control of the deaerator 13, and the exhaust gas G temperature on the outlet side of the economizer 3 is controlled. I have to.
Since the deaerator 13 is operated at the saturation temperature, the temperature of the boiler feed water W can be controlled by controlling the pressure of the deaerator 13.

  The municipal waste incineration plant treats the wastewater discharged from the plant with a wastewater treatment facility (not shown) attached to the plant, and allows the wastewater treatment water to pass the exhaust gas G temperature on the outlet side of the economizer 3 to the bag filter 5. It may be reused as the temperature-reduced water in the temperature-decreasing tower 4 for reducing the temperature to the end, and the wastewater treatment condition may be adopted so that the wastewater treatment water is not discharged out of the plant. Only a necessary amount may be used in the temperature-decreasing tower 4 and the remaining wastewater treated water may be discharged outside the plant.

  In FIG. 1, 18 is a forced blower, 19 is an air preheater, 20 is a secondary air blower, 21 is a burner, 22 is an ash extrusion device, 23 is an evaporating tube group, 24 is a low-temperature water injection nozzle, 25 Is a fly ash solidifying device, 26 is an accumulator (high pressure steam reservoir), 27 is a deaerator feed pump, and 28 is a boiler feed pump.

  Thus, according to the above-mentioned municipal waste incineration plant, the high-temperature exhaust gas G generated in the incinerator 1 is led to the boiler 2 and the economizer 3 and sequentially recovered by the boiler 2 and the economizer 3, and the temperature is continuously reduced. It is sent to the tower 4 where the temperature is lowered to the heat resistance temperature of the filter cloth material of the bag filter 5 by spraying the dewarmed water (waste water treatment water).

  The exhaust gas G whose temperature has been lowered in the temperature reducing tower 4 is guided to the bag filter 5 where dust and acid gas in the exhaust gas G are removed, and then the exhaust gas G becomes clean exhaust gas G. After that, it is discharged from the chimney 8 into the atmosphere.

On the other hand, the steam generated in the boiler 2 is superheated by the superheater 9 and supplied as superheated steam S to the power generation facility 10 including the steam turbine 10a and the generator 10b to drive the steam turbine 10a and the generator 10b. The power is generated and discharged from the steam turbine 10 a and condensed in the condenser 11, and then stored in the condensate tank 12.
Although not shown, the condensate tank 12 is supplied with makeup water from which impurities have been removed.

  The condensate stored in the condensate tank 12 is supplied to the deaerator 13 by the deaerator feed water pump 27 as boiler feed water W to the boiler 2, where the extracted steam S "(or from the steam turbine 10a) After being heated and degassed by the steam (a part of the superheated steam S supplied to the steam turbine 10a), it is supplied to the economizer 3 and the boiler 2 by the boiler feed pump 28.

  In the operation of the municipal waste incineration plant, the exhaust gas G temperature on the outlet side of the economizer 3 is constantly detected by the temperature detector 14, and when operating the deaerator 13, Using the exhaust gas G temperature as an index, the pressure of the deaerator 13 is controlled based on the exhaust gas G temperature on the outlet side of the economizer 3 to control the temperature of the boiler feed water W supplied to the economizer 3. The exhaust gas G temperature is changed to a temperature determined by the state of the apparatus such as the conventional bag filter 5 to improve the power generation amount.

That is, in the operation of the municipal waste incineration plant, the temperature of the exhaust gas G on the outlet side of the economizer 3 is always detected by the temperature detector 14, and the temperature of the exhaust gas G on the outlet side of the economizer 3 is determined to be a predetermined temperature (specification is determined). When the temperature is lower than the exhaust gas G temperature on the outlet side of the economizer 3), the set pressure of the deaerator 13 is increased to raise the temperature of the boiler feed water W, and the logarithmic average temperature difference in the heat exchange of the economizer 3 is lowered.
Thereby, the amount of heat exchange in the economizer 3 is reduced, and the exhaust gas G temperature on the outlet side of the economizer 3 can be increased.
As a result, the temperature of the exhaust gas G can be prevented from falling below the required gas temperature in the bag filter 5 even if a predetermined amount of temperature-reduced water is sprayed on the exhaust gas G in the temperature reducing tower 4.

Further, when the exhaust gas G temperature on the outlet side of the economizer 3 exceeds a predetermined temperature (exhaust gas G temperature on the outlet side of the economizer 3 whose specification has been determined), the set pressure of the deaerator 13 is lowered to lower the boiler feed water W temperature. The logarithmic average temperature difference in the heat exchange of the economizer 3 is increased.
Thereby, more heat of the exhaust gas G can be recovered and the power generation output can be improved.

Table 3 below shows the exhaust gas G temperature at the outlet side of the economizer 3, the amount of evaporation of the boiler 2, etc. during high-quality waste and standard waste when the municipal waste incineration plant is operated by the conventional operation method. .
That is, Table 3 below shows municipal waste under the condition that the economizer 3 is designed so that the exhaust gas G temperature on the outlet side of the economizer 3 becomes 210 ° C. during low-quality waste, and the pressure of the deaerator 13 is fixed at 0.29 MPa. It shows the exhaust gas G temperature at the outlet side of the economizer 3, the amount of evaporation of the boiler 2, etc. during high-quality waste and standard waste when the incineration plant is operated.
However, the amount of evaporation, the amount of reduced temperature water, the amount of gas on the inlet side of the bag filter 5 and the amount of power generation are all set to 100 in the conventional case.

  Actually, in the case of a municipal waste incineration plant equipped with two incinerators 1 with a capacity of 100 tons of municipal waste per day, the pressure of the deaerator 13 is 0.29 MPa (no change), and the economizer 3 at the time of standard waste Assuming that the exhaust gas G temperature at the outlet side is 200 ° C. when there is no drainage closed condition and 225 ° C. when there is a drainage closed condition, the amount of water to be reduced in the temperature reducing tower 4 is 24 tons per day when there is no drainage closed condition. The drainage discharge rate is 16 tons per day when the drainage closed condition is present, the drainage discharge is 8 tons per day when the drainage closed condition is not present, and 0 ton per day when the drainage closed condition is present, and the power generation amount is the drainage closed condition. It is 4500 kW when there is none, and 4400 kW when there is drainage closed condition.

  Table 4 below shows the exhaust gas G temperature at the outlet side of the economizer 3, the boiler evaporation amount, etc. at the time of high-quality waste and standard waste when the municipal waste incineration plant is operated by the operation method of the present invention. Yes, the pressure of the deaerator 13 is kept at 0.29 MPa at the time of low quality waste, and the pressure of the deaerator 13 is reduced to 0.17 MPa at the time of high quality waste and standard waste.

  As is clear from Table 4, the pressure of the deaerator 13 is kept as it is at the time of low-quality waste, and the pressure of the deaerator 13 is reduced to 0.17 MPa at the time of high-quality waste and reference waste, The water supply temperature to the economizer 3 is lowered from the conventional 143 ° C. to 130 ° C., the logarithmic average temperature difference in the economizer 3 is increased, and the amount of exchange heat is increased.

As a result, in the operation method of the present invention, the exhaust gas G temperature on the outlet side of the economizer 3 decreases during high-quality waste and standard waste, and the amount of evaporation and power generation increase, while the amount of reduced water and exhaust gas G increase. It can be seen that the amount decreases.
In addition, the operation method of this invention can acquire the effect mentioned above irrespective of the presence or absence of drainage closed conditions.

In addition, when the wastewater closed condition is adopted, the amount of dewarmed water in the temperature reducing tower 4 at the time of normal high-quality waste and standard waste is larger than the amount of wastewater treated water, and the deficit is replenished with fresh water. According to the operation method of the present invention, by reducing the pressure of the deaerator 13, the amount of temperature-reduced water in the temperature-decreasing tower 4 can be reduced as compared with the prior art as shown in Table 4, so Can be reduced.
Furthermore, according to the operating method of the present invention, as shown in Table 4, the amount of gas entering the bag filter 5 is slightly reduced, so that the equipment scale of the exhaust gas treatment facility can be reduced.

  Thus, in the operation method of the municipal waste incineration plant described above, the power generation efficiency can be improved by changing the exhaust gas G temperature on the outlet side of the economizer 3 to a temperature determined by the state of the conventional apparatus or more. In addition, the temperature of the exhaust gas G at the inlet of the bag filter 5 can be maintained at an appropriate temperature even if a necessary amount of water to be reduced is sprayed in the temperature reducing tower 4.

  In the operation method of the municipal waste incineration plant described above, the pressure of the deaerator 13 is lowered at the time of high-quality waste and reference waste, but in other operation methods, the frequency of waste generation is reduced. In order to obtain a system for obtaining a high power generation output at the time of high standard waste, the pressure of the deaerator 13 is reduced (for example, 017 MPa) at the time of standard waste, and the pressure of the deaerator 13 is increased at the time of high quality waste and low quality waste (for example, , 0.29 MPa), the exhaust gas G temperature on the outlet side of the economizer 3 may be increased higher than the expected value.

  In this case, high power generation output can be obtained at the time of standard waste, and the amount of heat absorbed by the boiler 2 can be suppressed at the time of high-quality waste, so that the specifications of the steam system such as the steam turbine 10a are not excessively large. The exhaust gas G temperature on the outlet side of the economizer 3 that can be designed and is required for low-quality waste can be realized.

  In the operation method of the municipal waste incineration plant described above, the operation index of the deaerator 13 is the exhaust gas G temperature on the outlet side of the economizer 3, but in the other operation methods, the temperature reducing tower 4 The pressure operation of the deaerator 13 may be performed by using the amount of dewarmed water at the index. At this time, the exhaust gas G temperature at the bag filter 5 inlet side is controlled to be constant.

For example, when the amount of water to be reduced used in the temperature reducing tower 4 is less than a predetermined amount, the pressure of the deaerator 13 is increased to increase the temperature of the boiler feed water W supplied to the economizer 3, and the heat in the economizer 3 is increased. Reduce the exchange amount.
As a result, even if the temperature-reduced water amount required for the exhaust gas G is sprayed in the temperature reduction tower 4, the temperature of the exhaust gas G can be kept below the required gas temperature in the bag filter 5.

On the other hand, when the amount of water to be reduced used in the temperature reducing tower 4 exceeds a predetermined amount, the pressure of the deaerator 13 is lowered to lower the temperature of the boiler feed water W supplied to the economizer 3, and the heat in the economizer 3 is reduced. Increase the amount of exchange.
Thereby, the exhaust gas G temperature on the outlet side of the economizer 3 is lowered, and the power generation amount can be improved.

In the operation method of the municipal waste incineration plant described above, the economizer is controlled by controlling the pressure of the deaerator 13 based on the exhaust gas G temperature on the outlet side of the economizer 3 or the amount of the dewarmed water used in the temperature reducing tower 4. 3, the temperature of the exhaust gas G on the outlet side of the economizer 3 is changed to control the temperature of the boiler feed water W supplied to the economizer 3. However, in other operation methods, the boiler feed water W supplied to the economizer 3 The temperature may be controlled by the feed water heater 6 provided on the outlet side of the deaerator 13 to change the exhaust gas G temperature on the outlet side of the economizer 3.
For example, when the pressure of the deaerator 13 is 0.13 MPa (the boiler feed water W temperature at the outlet of the deaerator 13 at this time is 130 ° C.) and the temperature of the boiler feed water W supplied to the economizer 3 is 130 ° C., When the amount of heat exchanged at the feed water heater 6 is zero (to prevent the boiler feed water W temperature from rising by stopping the inflow on the heating side) and the boiler feed water W temperature supplied to the economizer 3 is 143 ° C., the feed water heater 6 may be used for heating.

That is, the municipal waste incineration plant that implements the above-described method includes an incinerator 1 that incinerates municipal waste, a boiler 2 that recovers heat from the high-temperature exhaust gas G generated in the incinerator 1, and a boiler, as shown in FIG. An economizer 3 for further recovering the heat of the exhaust gas G discharged from 2, a temperature reducing tower 4 for spraying dehumidified water (waste water treatment water) onto the exhaust gas G that has passed through the economizer 3, and cooling the exhaust gas G; Bag filter 5 that removes soot and acid gas, an induction fan 7 that induces exhaust gas G in the incinerator 1, a chimney 8 that releases the exhaust gas G that has been cleaned into the atmosphere, and steam from the boiler 2 A power generation facility 10 composed of a steam turbine 10a and a generator 10b driven by a power generator, a condenser (not shown in FIG. 2) for condensing exhaust steam S ′ discharged from the steam turbine 10a, and a condenser From A condensate tank (not shown in FIG. 2) for storing condensate, a deaerator 13 for heating and degassing the condensate from the condensate tank and supplying it to the economizer 3 and the boiler 2 as boiler feed water W; The feed water heater 6 is provided between the deaerator 13 and the economizer 3 and controls the temperature of boiler feed water W supplied from the deaerator 13 to the economizer 3. In operation, the temperature of the boiler feed water W supplied to the economizer 3 by operating the feed water heater 6 based on the exhaust gas G temperature on the exit side of the economizer 3 based on the exhaust gas G temperature on the economizer 3 exit side. And the exhaust gas G temperature on the outlet side of the economizer 3 is changed to a temperature determined by the state of the conventional apparatus to improve the amount of power generation.
The feed water heater 6 uses a feed water heater, a reflux economizer, or the like having a structure in which the boiler feed water W is heated using the extracted steam S ″ from the steam turbine 10a.

In the operation of the above-mentioned municipal waste incineration plant, the exhaust gas G temperature on the outlet side of the economizer 3 is always detected by a temperature detector (not shown in FIG. 2), and the exhaust gas G temperature on the outlet side of the economizer 3 is predetermined. When the temperature falls below the temperature, the feed water heater 6 is automatically controlled to increase the exchange heat amount of the feed water heater 6, the temperature of the boiler feed water W supplied to the economizer 3 is increased, and the logarithmic average in the heat exchange of the economizer 3 Reduce the temperature difference. At this time, the deaerator 13 is operated with the pressure fixed.
Thereby, the amount of heat exchange in the economizer 3 is reduced, and the exhaust gas G temperature on the outlet side of the economizer 3 can be increased.
As a result, the temperature of the exhaust gas G can be prevented from falling below the required gas temperature in the bag filter 5 even if a predetermined amount of temperature-reduced water is sprayed on the exhaust gas G in the temperature reducing tower 4.

In addition, when the exhaust gas G temperature on the outlet side of the economizer 3 exceeds a predetermined temperature, the boiler feed water W supplied to the economizer 3 is automatically controlled by the feed water heater 6 to make the exchange heat amount of the feed water heater 6 small or zero. The logarithm average temperature difference in the heat exchange of the economizer 3 is increased. At this time, the deaerator 13 is operated with the pressure fixed.
Thereby, more heat of the exhaust gas G can be recovered and the power generation output can be improved.

  In the operation method of the municipal waste incineration plant described above, the operation index of the feed water heater 6 is the exhaust gas G temperature on the outlet side of the economizer 3, but in other operation methods, the temperature reducing tower 4 The operation of the feed water heater 6 may be performed using the amount of the temperature-reduced water at the index. At this time, the exhaust gas G temperature at the bag filter 5 inlet side is controlled to be constant.

For example, when the amount of water to be reduced used in the temperature reducing tower 4 is less than a predetermined amount, the exchange heat amount of the feed water heater 6 is increased to increase the temperature of the boiler feed water W supplied to the economizer 3, and the economizer 3 Reduce the amount of heat exchange.
As a result, even if the temperature-reduced water amount required for the exhaust gas G is sprayed in the temperature reduction tower 4, the temperature of the exhaust gas G can be kept below the required gas temperature in the bag filter 5.

On the other hand, when the amount of water to be reduced used in the temperature reducing tower 4 exceeds a predetermined amount, the temperature of the boiler feed water W supplied to the economizer 3 is lowered by reducing the exchange heat amount of the feed water heater 6, and the economizer 3 Increase the amount of heat exchange.
Thereby, the exhaust gas G temperature on the outlet side of the economizer 3 is lowered, and the power generation amount can be improved.

  In each operation method of the municipal waste incineration plant described above, the operation index of the deaerator 13 and the feed water heater 6 is defined as the exhaust gas G temperature at the outlet side of the economizer 3 or the amount of dewarmed water in the dewarming tower 4. However, in other operation methods, the pressure of the deaerator 13 using other indicators for estimating the exhaust gas G temperature on the outlet side of the economizer 3, for example, boiler evaporation amount, dust amount, dust quality, etc. You may make it perform operation and driving | operation operation of the feed water heater 6. FIG.

  1 is an incinerator, 2 is a boiler, 3 is an economizer, 4 is a temperature reducing tower, 5 is a bag filter, 6 is a feed water heater, 10 is a power generation facility, 10a is a steam turbine, 10b is a generator, and 13 is a deaerator. , 14 is a temperature detector, S is superheated steam, S 'is exhaust steam, and W is boiler feed water.

Claims (9)

  The exhaust gas discharged from the incinerator that incinerates municipal waste is passed through the boiler, economizer, temperature reduction tower, and bag filter in this order to recover the heat of the exhaust gas, adjust the temperature of the exhaust gas, and purify the exhaust gas. The steam is led to a power generation facility consisting of a steam turbine and a generator to generate power, and the condensate obtained by condensing exhaust steam discharged from the steam turbine is heated and degassed by a deaerator as boiler feed water. In the operation method of the municipal waste incineration plant that supplies to the economizer and boiler, the exhaust gas temperature at the outlet side of the economizer is used as an index when operating the deaerator, and it is based on the exhaust gas temperature at the outlet side of the economizer. The pressure of the deaerator is controlled to control the boiler feed water temperature supplied to the economizer, and the exhaust gas temperature on the outlet side of the economizer The method of operating MSW incineration plant, characterized in that so as to vary over temperature determined by the come of the device consequences.   In the operation method of the municipal waste incineration plant according to claim 1, when the exhaust gas temperature on the outlet side of the economizer is always detected by a temperature detector, and the exhaust gas temperature on the outlet side of the economizer is lower than a predetermined temperature, When the set pressure of the deaerator is increased to raise the temperature of boiler feed water supplied to the economizer to reduce the amount of heat exchange in the economizer, and when the exhaust gas temperature on the economizer outlet side exceeds the specified temperature A method for operating a municipal waste incineration plant, characterized in that the set pressure of the deaerator is lowered to lower the temperature of boiler feed water supplied to the economizer to increase the amount of heat exchange in the economizer.   The exhaust gas discharged from the incinerator that incinerates municipal waste is passed through the boiler, economizer, temperature reduction tower, and bag filter in this order to recover the heat of the exhaust gas, adjust the temperature of the exhaust gas, and purify the exhaust gas. The steam is led to a power generation facility consisting of a steam turbine and a generator to generate power, and the condensate obtained by condensing exhaust steam discharged from the steam turbine is heated and degassed by a deaerator as boiler feed water. In the operation method of the municipal waste incineration plant that supplies to the economizer and the boiler from the operation, when operating the deaerator, the amount of water used in the temperature reduction tower is used as an index, and the temperature reduction water used in the temperature reduction tower The pressure of the deaerator is controlled based on the amount to control the temperature of boiler feed water supplied to the economizer, and the exhaust gas temperature at the outlet side of the economizer The method of operating MSW incineration plant, characterized in that in the so varied over temperature determined.   In the operation method of the municipal waste incineration plant according to claim 3, when the amount of water to be reduced used in the temperature reduction tower is lower than a predetermined amount, the boiler supplied to the economizer by raising the set pressure of the deaerator If the temperature of the water supply is raised to reduce the amount of heat exchange in the economizer, and if the amount of dewarmed water used in the temperature-decreasing tower exceeds the specified amount, the set pressure of the deaerator is lowered and supplied to the economizer. The operation method of the municipal waste incineration plant characterized in that the heat exchange amount in the economizer is increased by lowering the temperature of the boiler feed water.   The exhaust gas discharged from the incinerator that incinerates municipal waste is passed through the boiler, economizer, temperature reduction tower, and bag filter in this order to recover the heat of the exhaust gas, adjust the temperature of the exhaust gas, and purify the exhaust gas. After the steam is led to a power generation facility consisting of a steam turbine and a generator to generate electric power, and the condensed water obtained by condensing the exhaust steam discharged from the steam turbine is heated and degassed by a deaerator as boiler feed water In the operation method of the municipal waste incineration plant in which the temperature of the boiler feed water is controlled by the feed water heater provided on the outlet side of the deaerator and then supplied to the economizer and the boiler, the feed water heater is operated. Using the exhaust gas temperature at the outlet side of the economizer as an index, the economizer is operated by operating the feed water heater based on the exhaust gas temperature at the outlet side of the economizer The operation method of the municipal waste incineration plant, characterized in that the temperature of the boiler feed water supplied to the engine is controlled so that the exhaust gas temperature on the exit side of the economizer is changed to a temperature determined by the behavior of the conventional equipment or more. .   In the operation method of the municipal waste incineration plant according to claim 5, when the exhaust gas temperature on the outlet side of the economizer is always detected by a temperature detector, and the exhaust gas temperature on the outlet side of the economizer is lower than a predetermined temperature, When the exchange heat quantity of the feed water heater is increased to increase the boiler feed water temperature supplied to the economizer to reduce the heat exchange quantity at the economizer, and the exhaust gas temperature on the economizer outlet side exceeds the specified temperature The operation method of the municipal waste incineration plant characterized in that the heat exchange amount in the economizer is increased by reducing the temperature of boiler feed water supplied to the economizer with the exchange heat amount of the feed water heater being reduced or reduced to zero. .   The exhaust gas discharged from the incinerator that incinerates municipal waste is passed through the boiler, economizer, temperature reduction tower, and bag filter in this order to recover the heat of the exhaust gas, adjust the temperature of the exhaust gas, and purify the exhaust gas. After the steam is led to a power generation facility consisting of a steam turbine and a generator to generate electric power, and the condensed water obtained by condensing the exhaust steam discharged from the steam turbine is heated and degassed by a deaerator as boiler feed water In the operation method of the municipal waste incineration plant in which the temperature of the boiler feed water is controlled by the feed water heater provided on the outlet side of the deaerator and then supplied to the economizer and the boiler, the feed water heater is operated. The amount of water used in the temperature reduction tower is used as an index, and the water heater is operated based on the amount of water used in the temperature reduction tower and supplied to the economizer. Ira feed water to control the temperature, the exhaust gas temperature at the outlet side of the economizer, the method of operating MSW incineration plant, characterized in that so as to vary over temperature determined by the conventional apparatus consequences.   In the operation method of the municipal waste incineration plant according to claim 7, when the amount of water to be reduced used in the temperature reduction tower is lower than a predetermined amount, the exchange heat amount of the feed water heater is increased and supplied to the economizer. Increase the boiler feed water temperature to reduce the amount of heat exchange in the economizer, and if the amount of dewarmed water used in the temperature reduction tower exceeds the specified amount, reduce the amount of heat exchanged in the water heater to the economizer. A method of operating a municipal waste incineration plant, characterized in that the temperature of boiler feed water supplied is lowered to increase the amount of heat exchange in the economizer.   A method for operating a municipal waste incineration plant according to claim 1, claim 2, claim 3, claim 4, claim 5, claim 6, claim 7 or claim 8, wherein said spraying is performed in a temperature reducing tower. The wastewater treatment conditions are such that the wastewater treated from the municipal waste incineration plant is used as the dewarmed water, and all the wastewater treated water is used in the temperature reduction tower so that the wastewater treated water is not discharged outside the plant. A method of operating a municipal waste incineration plant, characterized by adoption.

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