JP2009236363A - Waste heat treatment system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a waste heat treatment system capable of minimizing reduction in the amount of power generation even when the spray amount of waste water treatment water is large. <P>SOLUTION: The waste heat treatment system is provided with a waste incinerator 1; a boiler 2 for recovering heat of exhaust gas discharged from the waste incinerator 1; a temperature reducing tower 3 for spraying cooling water to the exhaust gas which has passed through the boiler 2; a dust collector 6 for purifying the exhaust gas which has passed through the temperature reducing tower 3; a gas reheater 7 for increasing the temperature of the exhaust gas which has passed through the dust collector 6; catalyst NOx removal equipment 8 for removing nitrogen oxides in the exhaust gas which has passed through the gas reheater 7; an induced draft fan 10 for inducing the exhaust gas which has passed through the catalyst NOx removal equipment 8; and a smoke stack 11 for emitting the exhaust gas which has passed through the induced draft fan 10 to the atmosphere. A cooling water spraying device 9 for spraying cooling water is provided in an exhaust gas path between the catalyst NOx removal equipment 8 and the induced draft fan 10. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a waste heat treatment system that performs high-efficiency power generation using exhaust gas discharged from a waste heat treatment facility such as a waste incinerator.

  Waste treatment facilities such as waste incinerators are equipped with wastewater treatment equipment for treating wastewater generated from this facility, and the treated water (wastewater treatment water) from this wastewater treatment equipment is placed in the facility. Is often reused. On the other hand, in recent years, heat utilization of waste has been promoted from the viewpoint of effective utilization of unused energy, and heat recovery is generally performed by installing a boiler in this type of heat treatment facility. Then, when a boiler is installed, it becomes a new problem which use of the waste water treated water used for the combustion gas cooling device is used.

  When reusing all or most of the wastewater treated water, the most effective reuse is to reduce the gas temperature by blowing water into the exhaust gas dewarmed water, in other words, the exhaust gas from the boiler. Water for making the temperature suitable for a subsequent exhaust gas treatment facility such as

  FIG. 2 shows an example of this type of conventional waste heat treatment system. In this conventional system, a boiler 52 is installed at the exhaust gas outlet of the incinerator 51 and heat recovery is performed by the boiler 52. The steam turbine 53 is driven by the steam from the boiler 52 and the generator 54 is driven. . The exhaust gas that has passed through the boiler 52 is cooled by the temperature reducing tower 55 and then sent to a dust collector 56 such as a bag filter. The dust collector 56 removes dust in the exhaust gas. Furthermore, after the exhaust gas that has passed through the dust collector 56 is reheated by the gas reheater 57, nitrogen oxides in the exhaust gas are removed by the catalyst denitration device 58, and the exhaust gas is removed from the chimney 60 via the induction fan 59. Released into the atmosphere. Here, the waste water treated water stored in the reuse water tank 61 is used as the exhaust gas temperature-reduced water sprayed in the temperature reducing tower 55.

  By the way, in the above-described conventional system, when the excess drainage (wastewater treatment water) generated in the facility cannot be discharged out of the field or only a small amount can be discharged, all or most of the wastewater treatment is performed in the cooling tower 55 in the system. Must be sprayed with water. However, when the entire amount or most of the wastewater treated water in the facility is treated in the temperature reducing tower 55 in this way, the outlet temperature of the boiler 52 must be increased, and as a result, the heat recovery of the boiler 52 is reduced. There is a problem that the amount of power generation decreases.

  The present invention has been made to solve the above-described problems, and provides a waste heat treatment system capable of minimizing a decrease in power generation even when the amount of sprayed wastewater is large. It is for the purpose.

In order to achieve the above object, a waste heat treatment system according to the present invention comprises:
A waste incinerator, a boiler that recovers heat of exhaust gas discharged from the waste incinerator, a temperature reducing tower that sprays cooling water on the exhaust gas after passing through the boiler, and an exhaust gas after passing through the temperature reducing tower. A dust collector for purification treatment, a gas reheater for heating the exhaust gas after passing through the dust collector, a catalyst denitration device for removing nitrogen oxides in the exhaust gas after passing through the gas reheater, and the catalyst In a waste heat treatment system comprising an induction fan for attracting exhaust gas after passing through a denitration device, and a chimney for releasing the exhaust gas after passing through the induction fan to the atmosphere,
A cooling water spraying device for spraying cooling water is provided in an exhaust gas path between the catalyst denitration device and the induction fan.

  Here, as the cooling water sprayed on the temperature reducing tower and the cooling water spraying device, it is preferable to use treated water from a wastewater treatment facility for treating wastewater generated from the waste heat treatment system.

  According to the present invention, since the cooling water spraying device is arranged at the subsequent stage of the catalyst denitration device, even when the amount of the cooling water sprayed into the system is large, to the temperature reducing tower provided at the subsequent stage of the boiler. The amount of spraying can be suppressed. For this reason, it is not necessary to increase the outlet temperature of the boiler, and high-efficiency power generation can be achieved. In addition, since the actual gas amount of the exhaust gas entering the induction fan disposed downstream of the cooling water spray device can be reduced, there is an advantage that an induction fan having a smaller power than the conventional one can be used. .

  In the present invention, if the treated water from the waste water treatment facility for treating the waste water generated from the waste heat treatment system is used as the cooling water sprayed on the temperature reducing tower and the cooling water spray device, the waste treatment Heat can be recovered with high efficiency and the amount of exhaust gas can be reduced without discharging waste water from the system to the outside.

  Next, specific embodiments of the waste heat treatment system according to the present invention will be described with reference to the drawings.

  FIG. 1 is an overall configuration diagram of a waste heat treatment system according to an embodiment of the present invention.

  In the waste heat treatment system of the present embodiment, an incinerator (heat treatment apparatus) 1 for incinerating general waste or industrial waste is provided, and a boiler 2 is installed at an exhaust gas outlet of the incinerator 1. A temperature reducing tower (exhaust gas temperature reducing device) 3 is installed on the downstream side. Further, the steam turbine 4 is driven by the steam generated from the boiler 2 to drive the generator 5. A dust collector 6 such as a bag filter is installed on the downstream side of the temperature reducing tower 3. A gas reheater 7, a catalyst denitration device 8, a cooling water spray device (drainage) is disposed on the downstream side of the dust collector 6. A spraying device 9, an induction blower 10, and a chimney 11 are installed.

  Further, in this waste heat treatment system, a waste water treatment facility for treating waste water generated from the system is attached, and treated water (waste water treated water) from this waste water treatment facility is stored in the reuse water tank 12. Has been. The temperature reducing tower 3 and the waste water spraying device 9 are reused by being supplied with waste water treated water stored in the reuse water tank 12.

  In such a configuration, the exhaust gas discharged from the incinerator 1 is introduced into the boiler 2 to recover heat in the boiler 2, and the steam turbine 4 and the generator 5 are driven by the steam from the boiler 2. The The exhaust gas having a temperature t1 that has passed through the boiler 2 is cooled by the temperature reducing tower 3 and reduced to a predetermined temperature or less, and then sent to the dust collector 6, where dust, HCl, SOx, Dioxins are removed. Further, the exhaust gas that has passed through the dust collector 6 is heated by the gas reheater 7 and then sent to the catalyst denitration device 8 to remove nitrogen oxides (NOx) in the exhaust gas, and then drain spray. The temperature is reduced by spraying the cooling water in the device 9, sucked by the induction blower 10, and discharged from the chimney 11 to the atmosphere.

  Here, the exhaust gas temperature t2 after passing through the dust collector 6 is 150 ° C. to 190 ° C., preferably 160 ° C., which is the temperature at which the acid gas removing agent easily reacts. The exhaust gas temperature t3 after passing through the gas reheater 7 is 180 ° C. to 230 ° C., preferably 210 ° C., which is a temperature with good NOx removal efficiency in the catalyst denitration device 8. Since the exhaust gas temperature t2 after passing through the dust collector 6 is thus fixed, in the conventional system shown in FIG. 2, if the amount of cooling water supplied to the temperature reducing tower 3 increases, the exhaust gas after passing through the boiler 2 It is necessary to raise the temperature t1, and if the exhaust gas temperature t1 is raised, the amount of steam supplied to the steam turbine 4 is reduced, and the amount of power generated by the generator 5 is reduced.

  However, in the system of this embodiment, the waste water spray device 9 is provided on the rear stage side of the catalyst denitration device 8, and the waste water treated water stored in the reuse water tank 12 is supplied to the waste water spray device 9. Therefore, the amount of waste water treated water supplied to the temperature reducing tower 3 can be reduced. In this way, it is not necessary to increase the outlet temperature of the boiler, and high efficiency power generation can be achieved. The exhaust gas temperature t4 on the upstream side of the waste water spray device 9 is reduced to a temperature t5 (about 120 ° C. to 160 ° C.) at which the exhaust gas does not condense due to the temperature decrease in the waste water spray device 9. Further, according to the system of the present embodiment, the actual gas amount of the exhaust gas entering the induction fan 10 disposed downstream of the drain spray device 9 can be reduced. Machine 10 can be used.

  The drain spray device 9 used in the present embodiment may be a temperature reducing tower having the same configuration as the temperature reducing tower 3, or may be one that sprays cooling water directly on the flue.

  The present invention is a system suitable for use in a waste incineration power generation system that generates power using heat generated by incineration of waste.

1 is an overall configuration diagram of a waste heat treatment system according to an embodiment of the present invention. Overall configuration diagram of a conventional waste heat treatment system

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Incinerator 2 Boiler 3 Temperature reducing tower 4 Steam turbine 5 Generator 6 Dust collector 7 Gas reheater 8 Catalyst denitration device 9 Cooling water spray device (drainage spray device)
10 Induction fan 11 Chimney 12 Reuse water tank

Claims (2)

A waste incinerator, a boiler that recovers heat of exhaust gas discharged from the waste incinerator, a temperature reducing tower that sprays cooling water on the exhaust gas after passing through the boiler, and an exhaust gas after passing through the temperature reducing tower. A dust collector for purification treatment, a gas reheater for heating the exhaust gas after passing through the dust collector, a catalyst denitration device for removing nitrogen oxides in the exhaust gas after passing through the gas reheater, and the catalyst In a waste heat treatment system comprising an induction fan for attracting exhaust gas after passing through a denitration device, and a chimney for releasing the exhaust gas after passing through the induction fan to the atmosphere,
A waste heat treatment system, wherein a cooling water spraying device for spraying cooling water is provided in an exhaust gas path between the catalyst denitration device and the induction fan.   2. The waste heat treatment system according to claim 1, wherein treated water from a waste water treatment facility for treating waste water generated from the waste heat treatment system is used as the cooling water sprayed on the temperature reducing tower and the cooling water spray device.

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