JP6915873B2 - Exhaust gas treatment equipment and exhaust gas treatment method - Google Patents

Description

The present invention relates to an exhaust gas treatment device having an exhaust gas cooling device for cooling exhaust gas discharged from an incinerator such as waste by water spray, and an exhaust gas treatment method.

For example, Patent Document 1 describes a white smoke prevention device for combustion equipment. The combustion equipment removes a combustion device that is a waste incinerator, a gas cooling device that injects cooling water into the exhaust gas from the combustion device to cool it, and an acidic gas contained in the exhaust gas from the gas cooling device. A dry exhaust gas treatment device, a filtration type dust collector that removes soot and dust contained in future exhaust gas, and a catalytic denitration device that removes nitrogen oxides contained in the exhaust gas from this filtration type dust collector. It is equipped with an attracting ventilator that attracts exhaust gas from this catalytic denitration device and a chimney that discharges exhaust gas from this attracting ventilator to the atmosphere.

The white smoke prevention device has a configuration in which a water vapor separation device for selectively removing water vapor is provided in an exhaust gas path from the gas cooling device to the chimney of the combustion equipment.

For example, Patent Document 2 describes a thermal power generation system. This thermal power generation system includes a power generation system, an exhaust gas treatment system, a water treatment system, and a steam recovery system in exhaust gas.

In the power generation system, coal is pulverized and burned in a pulverized coal combustion boiler to generate high-pressure and low-pressure steam, and the steam rotates a turbine to obtain electric power.

The water treatment system extracts a part of the boiler water obtained by condensing the high-pressure and low-pressure steam generated by the pulverized coal combustion boiler and stores it in the boiler blow water storage tank, and stores the stored boiler blow water in the power plant. It will be supplied to the power plant as other water for the plant.

The exhaust gas treatment system removes particulate matter such as soot and dust contained in the exhaust gas obtained by burning pulverized coal in the pulverized coal combustion boiler with an electrostatic precipitator, and removes harmful substances such as NOx contained in the exhaust gas. Denitration is performed by a denitration device, and harmful substances such as SOx contained in the exhaust gas are brought into contact with desulfurization water in the desulfurization device to desulfurize.

The steam recovery system in exhaust gas separates a part of steam in the desulfurized exhaust gas, cools and condenses it, stores the extracted condensed water in a steam recovery water tank, and supplies it to the pulverized coal combustion boiler.

Japanese Patent No. 4074826 JP-A-2017-89611

The above-mentioned Patent Document 1 describes that the water vapor contained in the exhaust gas generated by the combustion of waste in the waste incinerator is separated by using a steam separation membrane to prevent white smoke from being generated from the chimney. However, there is no description that the water vapor separated from the exhaust gas is used for something.

On the other hand, in Patent Document 2, after desulfurizing the exhaust gas obtained by burning pulverized coal in the pulverized coal combustion boiler of the power generation system by contacting it with water sprinkler in a desulfurization apparatus, the steam in the desulfurized exhaust gas is discharged. It is described that the water vapor is separated by the water vapor separation film of the exhaust gas water vapor recovery system, and further, the water vapor separated from the desulfurized exhaust gas by the water vapor separation film of the exhaust gas water vapor recovery system is condensed by an air-cooled condenser. A part of the water and a part of the condensed water (boiler water) discharged from the air-cooled water condenser of the power generation system are supplied to the desulfurization device of the exhaust gas treatment system as needed, and the remaining boiler blow. It is stated that water will be used as steam for power plants.

However, in Patent Document 2, the exhaust gas generated by the combustion of the waste in the waste incinerator is cooled by contacting it with the cooling water by the cooling device, so that the water vapor contained in the exhaust gas causes the smoke to be white. It is not possible to see the technical idea of preventing the phenomenon of smoke generation and the technical idea of reusing the water vapor contained in the exhaust gas as the cooling water of the cooling device.

In view of such circumstances, an object of the present invention is to provide an exhaust gas treatment apparatus and an exhaust gas treatment method capable of reducing the exhaust gas treatment cost while suppressing or preventing white smoke from the chimney.

The present invention provides an exhaust gas cooling device that reduces the temperature by injecting cooling water into the exhaust gas discharged from a waste incinerator, a filtration type dust collector that purifies the exhaust gas that has passed through the exhaust gas cooling device, and this filtration. An exhaust gas treatment device including a chimney that discharges exhaust gas that has passed through the dust collector to the atmosphere, and a chemical supply device that supplies a neutralizing agent that neutralizes the acidic gas contained in the exhaust gas to the filtration dust collector. Therefore, the steam separator film of the hollow filament film provided in the flue on the downstream side of the filtration type dust collector and separating the steam in the exhaust gas passing through the flue, and the steam separated by the steam separator film are separated. A condensate device for returning to water and a condensate reusing device for reusing the water reconstituted by the condensate device as cooling water for the exhaust gas cooling device are provided. The condenser is provided with a condensate tank for storing the condensed water of the device, and the condenser is provided to communicate the hot water tank for storing the hot water, the steam separation membrane, and the condensate tank. A heat exchanger for transferring the heat of the steam passing through the passage and the steam recovery path to the hot water in the hot water tank, and the hot water in the hot water tank is circulated between the hot water tank and the heat exchanger. A circulation pump for causing the hot water to be circulated, and a heat exchange passage for circulating the hot water in the hot water tank so as to take it out from the hot water tank and return it, and an intermediate portion thereof is arranged in the heat exchanger close to the steam recovery path. It is characterized by having.

In this configuration, the temperature was reduced by injecting cooling water by the exhaust gas cooler to the exhaust gas discharged from the incinerator, separating water vapor in the exhaust gas that has passed through the filter-type dust collector, and this separation The water vapor is returned to water, and this water is reused as cooling water for the exhaust gas cooling device.

As a result, not only white smoke is not emitted from the chimney, but also the amount of tap water or well water used as the cooling water can be reduced, so that the purchase cost can be reduced. It will be possible to contribute to the reduction of cooling cost. As a result, the exhaust gas treatment cost can be reduced, and the cooling water can be supplied by the steam generated by combustion even in the dry season, so that the operation of the incinerator can be continued without stopping.

By the way, the exhaust gas treatment device includes a bypass passage provided in the flue so as to bypass the water vapor separation membrane, a bypass damper provided in the bypass passage to control the passage amount of exhaust gas, and if necessary. It is preferable to further include a control device for adjusting the amount of water vapor separated by the water vapor separation membrane by controlling the amount of exhaust gas introduced into the water vapor separation membrane by the bypass damper.

In this configuration, the amount of water vapor in the exhaust gas returned to water can be adjusted as needed, so that the generation of excess water can be avoided.

Further, the exhaust gas treatment apparatus, it is preferable to utilize the heat recovered in the previous SL heat exchanger further comprises a binary generator for generating power.

In this configuration, since the latent heat of the water vapor separated by the water vapor separation membrane is converted into electric power by the binary generator, for example, it is used in the exhaust gas treatment device according to the present invention or in a plant equipped with the exhaust gas treatment device. It will be possible to contribute to the reduction of exhaust gas treatment costs, such as the reduction of the cost of purchasing electric power from an electric power company.

Further, in the present invention, the temperature of the exhaust gas discharged from the waste incinerator is reduced by injecting cooling water into the exhaust gas discharged from the waste incinerator by an exhaust gas cooling device, and the acidic gas in the reduced temperature exhaust gas is supplied from the chemical supply device. This is an exhaust gas treatment method that removes soot and dust in the exhaust gas with a Japanese chemical and releases the exhaust gas from the chimney to the atmosphere. Water vapor in the exhaust gas that has passed through the filtration type dust collector. A steam separation treatment that separates the water vapor with a steam separation membrane of a hollow thread film, a water recovery treatment that returns the separated water vapor to water by a water recovery device having the above-described configuration, and cooling water of the exhaust gas cooling device. It is characterized by executing the recovery water reuse treatment to be reused as.

In this configuration, the temperature is lowered by injecting cooling water into the high-temperature exhaust gas by the exhaust gas cooling device, the water vapor in the exhaust gas that has passed through the filtration type dust collector is separated, and the separated water vapor is returned to water. , This water is reused as cooling water for the exhaust gas cooling device.

As a result, not only white smoke is not emitted from the chimney, but also the amount of tap water or well water used as the cooling water can be reduced, so that the purchase cost can be reduced. It will be possible to contribute to the reduction of cooling cost. As a result, it becomes possible to reduce the exhaust gas treatment cost.

Further, in the exhaust gas treatment method, in the water vapor separation process, the partial amount of released steam is adjustable by controlling the amount of exhaust gas to be introduced into the water vapor separation membrane as required, it is preferable.

In this configuration, the amount of water vapor in the exhaust gas returned to water can be adjusted as needed, so that the generation of excess water can be avoided.

Further, in the exhaust gas treatment method, it is preferable to further execute a power generation treatment in which the latent heat of the water vapor separated by the water vapor separation membrane is recovered and the recovered heat is used to generate electricity by a binary generator.

In this configuration, since the latent heat of the water vapor separated by the water vapor separation membrane is converted into electric power by the binary generator, for example, it is used in the exhaust gas treatment device according to the present invention or in a plant equipped with the exhaust gas treatment device. It will be possible to contribute to the reduction of exhaust gas treatment costs, such as the reduction of the cost of purchasing electric power from an electric power company.

The exhaust gas treatment apparatus and the exhaust gas treatment method according to the present invention can reduce the exhaust gas treatment cost while suppressing or preventing white smoke from the chimney.

It is a figure which shows the schematic structure of one Embodiment of the exhaust gas treatment apparatus which concerns on this invention.

Hereinafter, the best embodiment for carrying out the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention. In the figure, 1 is an incinerator for waste and the like, 2 is an exhaust gas cooling device, 3 is a filtration type dust collector, 4 is an attracting ventilator, and 5 is a chimney.

The incinerator 1 burns waste such as general waste (not shown), industrial waste, and infectious medical waste contained in a predetermined package, and the type of the incinerator does not matter.

Exhaust gas cooler 2, although not shown in detail, the exhaust gas that will be discharged from the incinerator 1 is introduced to decrease the temperature by spraying cooling water to the exhaust gas.

The filtration type dust collector 3 is a so-called bug filter, and collects particulate matter such as soot and dust in the exhaust gas whose temperature has been reduced by the exhaust gas cooling device 2. Although not shown, a large number of filter cloths are installed inside the filtration type dust collector 3.

The attraction ventilator 4 sucks the exhaust gas in the filtration type dust collector 3 and releases it from the chimney 5 into the atmosphere.

In this embodiment, a chemical supply device 7 for blowing a neutralizing chemical at a position near the exhaust gas introduction port is provided in the flue on the upstream side of the filtration type dust collector 3.

The chemical supply device 7 measures the concentration of the acidic gas in the exhaust gas at the outlet of the filtration type dust collector 3, and neutralizes the acidic gas in the exhaust gas generated by performing the incineration operation of the incinerator for a predetermined time. The amount of the neutralizing agent required for the filtration is calculated, and the calculated amount of the neutralizing agent is blown into the flue gas on the inlet side of the filtration type dust collector 3 in a fixed amount within a predetermined time to perform filtration. A precoat layer made of a neutralizing agent for the acidic gas contained in the exhaust gas is formed on the filter cloth of the type dust collector 3. Examples of the neutralizing agent include slaked lime and baking soda.

Before forming the precoat layer, compressed air is jet-jetted into the filtration type dust collector 3 in a pulsed manner to remove the deposits on the filter cloth surface in the filtration type dust collector 3. It is preferable to do.

In this embodiment, in order to further separate and reuse the water vapor contained in the exhaust gas, a hollow fiber membrane water vapor separation membrane 10, a water recovery device 20, a recovered water reuse device 30, a binary generator 40, and the like are used. I have.

The water vapor separation membrane 10 is provided in the flue 6 on the downstream side of the filtration type dust collector 3, specifically, the flue 6 from the attracting ventilator 4 to the chimney 5, and the exhaust gas passing through the flue 6. It selectively separates the water vapor inside.

The flue 6 is provided with a bypass passage 11 so as to bypass the water vapor separation membrane 10. The bypass passage 11 is provided with a bypass damper 12 that controls the amount of exhaust gas passing through the bypass passage 11.

The condensate device 20 cools steam and returns it to water, and includes a steam recovery path 21, a heat exchanger 22, a hot water tank 23, a circulation pump 24, a heat exchange passage 25, and the like.

The water vapor recovery path 21 is provided so as to communicate the water vapor separation membrane 10 with the condensate tank 31 of the following recovered water recycling device 30. The heat exchanger 22 is arranged close to the water vapor recovery path 21 and exchanges heat from the water vapor passing through the water vapor recovery path 21. The circulation pump 24 circulates the hot water in the hot water tank 23 between the hot water tank 23 and the heat exchanger 22. The circulation pump 24 is arranged on the discharge side of the hot water tank 23 in the heat exchange passage 25.

The recovered water reuse device 30 reuses the water recovered by the water recovery device 20 as cooling water for the exhaust gas cooling device 2, and is a water recovery tank 31, a first water supply channel 32, and a second water supply channel 33. , A first pump 34, a second pump 35, and the like.

The binary generator 40 generates electricity by utilizing the heat of steam separated by the steam separation membrane 10, and includes a circulation path 41, a supply pump 42, and the like.

Specifically, the binary generator 40 heats and evaporates the medium between the binary generators 40 with the hot water in the hot water tank 23, and turns the turbine (not shown) with the steam, whereby the steam and the hot water are combined. It is called binary cycle power generation, which uses the heat cycle between them to generate power. The supply pump 42 is arranged on the discharge side of the hot water tank 23 in the circulation path 41.

The bypass damper 12, the circulation pump 24, the first pump 34, the second pump 35, and the supply pump 42 are controlled by a control device (not shown).

Next, an exhaust gas treatment method using the exhaust gas treatment device according to this embodiment will be described.

In the waste incinerator operation, waste is incinerated by supplying primary combustion air into the incinerator 1, and further, secondary combustion air is supplied to the combustion gas that rises with this incinerator to reburn the combustion gas. I try to let you.

Exhaust gas that will be discharged from the incinerator 1, the acid gas in the exhaust gas from being GenAtsushi by example, 200 ° C. or less be contacted with the cooling water in the exhaust gas cooling device 2, to be introduced into the filter-type dust collector 3 And soot and dust are removed and released from the chimney 5 to the atmosphere.

In such an exhaust gas treatment process, the water vapor in the exhaust gas is separated by introducing the exhaust gas passing through the flue 6 on the downstream side of the filtration type dust collector 3 into the water vapor separation membrane 10 in an amount required. (Steam separation treatment). As a result, the emission of white smoke from the chimney 5 is suppressed or prevented.

In the water vapor separation process, by controlling the bypass damper 12 to the exhaust gas amount to be introduced into the water vapor separation membrane 10 optionally it has become possible to adjust the amount amount of released steam.

Then, the water vapor separated by the water vapor separation membrane 10 is condensed by the condensate device 20 and returned to water (condensation treatment).

In this water recovery treatment, the water vapor separated by the water vapor separation film 10 is conveyed to the water vapor recovery tank 31 via the water vapor recovery path 21, and in this process, the heat of the water vapor passing through the water vapor recovery path 21 is the heat exchanger. It will be transmitted to the hot water circulating in 22 and the heat exchange passage 25, and the hot water will be heated.

In such a condensate process, for example, steam at 160 ° C. to 180 ° C. becomes water (warm water) whose temperature has been reduced to, for example, 80 ° C. or lower, so that this water is transported and stored in the condensate tank 31. Become. On the other hand, the heat of the heated hot water is converted into electric power by the binary generator 40.

The water stored in the condensate tank 31 is reused as cooling water for the exhaust gas cooling device 2 and water for a plant provided with the exhaust gas treatment device as needed (recovered water reuse treatment).

In this recovered water reuse process, by operating the first pump 34 as needed, it can be supplied as cooling water to the exhaust gas cooling device 2 via the first water supply channel 32, and the second pump is needed. By operating 35, it can be supplied as water for the plant via the second water supply channel 33. A branch passage 36 is provided in the middle of the first water supply passage 32, and the cooling water in the condensate tank 31 can be supplied to the incinerator 1 from the branch passage 36.

Exhaust gas in the embodiment according to the present invention as described, the temperature was reduced by injecting cooling water into the exhaust gas discharged from the incinerator by the exhaust gas cooler 2, which has passed through the filter-type dust collector 3 or more The water vapor inside is separated, and the separated water vapor is returned to water so that this water can be reused as cooling water for the exhaust gas cooling device 2.

As a result, not only white smoke is not emitted from the chimney 5, but also the amount of tap water or well water used as the cooling water can be reduced, so that the purchase cost can be reduced. , It will be possible to contribute to the reduction of cooling cost. As a result, the exhaust gas treatment cost can be reduced, and the cooling water can be supplied by the steam generated by combustion even in the dry season, so that the operation of the incinerator can be continued without stopping.

Further, in the above embodiment, the amount of water vapor in the exhaust gas returned to water can be adjusted as needed, so that the generation of excess water can be avoided.

Further, in the above embodiment, the heat (latent heat + sensible heat) of the water condensed by the condensate device 20 is converted into electric power by the binary generator 40. It will be possible to contribute to the reduction of exhaust gas treatment costs, such as by reducing the cost of purchasing electric power used in a plant equipped with an exhaust gas treatment device from an electric power company.

The present invention is not limited to the above embodiment, and can be appropriately modified within the scope of claims and within the scope equivalent to the scope.

(1) In the above embodiment, an example is given in which the heat of the steam separated by the steam separation membrane 10 is used to generate electricity in the binary generator 40, but the present invention is not limited to this. It is also possible to eliminate the binary generator 40, for example.

(2) In the above embodiment, an example in which the water stored in the condensate tank 31 is reused as water for an exhaust gas treatment facility is given, but the present invention is not limited to this. For example, the water stored in the condensate tank 31 can be reused only as the cooling water of the exhaust gas cooling device 2 without being reused as the water for the exhaust gas treatment facility, and as much steam as possible in the event of a disaster. It is possible to use it as domestic water by separating it.

(3) In the above embodiment, an example in which the amount of water vapor separated from the exhaust gas can be adjusted is given, but the present invention is not limited to this, for example, the bypass passage 11 and the bypass damper. It is also possible to have a configuration in which 12 is eliminated.

(4) In the above embodiment, an example in which a branch path 36 is provided in the middle of the first water supply channel 32 is given, but the present invention is not limited to this, and for example, a configuration in which the branch path 36 is eliminated. It is also possible to.

The present invention can be suitably used for an exhaust gas treatment device and an exhaust gas treatment method.

1 Incinerator 2 Exhaust gas cooling device 3 Filtration type dust collector 4 Inducing ventilator 5 Chimney 6 Flue 7 Chemical supply device 10 Water vapor separation membrane
11 Bypass passage
12 Bypass damper 20 Condenser
21 Water vapor recovery path
22 heat exchanger
23 Hot water tank
24 Circulation pump
25 Heat exchange passage 30 Recovered water reuse device
31 Condensate tank
32 1st water supply channel
33 Second water supply channel
34 1st pump
35 Second pump
36 branch road 40 binary generator
41 Circulation route
42 Supply pump

Claims (6)

An exhaust gas cooling device that reduces the temperature by injecting cooling water into the exhaust gas discharged from the waste incinerator,
A filtration type dust collector that purifies the exhaust gas that has passed through this exhaust gas cooling device,
A chimney that releases the exhaust gas that has passed through this filtration type dust collector to the atmosphere,
An exhaust gas treatment device including a chemical supply device for supplying a neutralizing agent for neutralizing an acid gas contained in an exhaust gas to the filtration type dust collector.
A water vapor separation membrane of a hollow fiber membrane provided in the flue on the downstream side of the filtration type dust collector and separating water vapor in the exhaust gas passing through the flue.
A condenser that returns the water vapor separated by this water vapor separation membrane to water,
A recovered water reclaiming device for reclaiming the water recovered by this condensing device as cooling water for the exhaust gas cooling device is provided.
The recovered water reuse device includes a condensate tank for storing the water recovered by the condensate device.
In the condensate device, a hot water tank for storing hot water, a steam recovery path provided so as to communicate the steam separation membrane and the condensate tank, and the heat of steam passing through the steam recovery path are transferred to the hot water tank. A heat exchanger for transmitting to the hot water inside, a circulation pump for circulating the hot water in the hot water tank between the hot water tank and the heat exchanger, and taking out the hot water in the hot water tank from the hot water tank. An exhaust gas treatment apparatus characterized in that the heat exchange passage is provided so as to be circulated so as to be returned to the water vapor, and an intermediate portion thereof is arranged in the heat exchanger in the vicinity of the steam recovery path. In the exhaust gas treatment apparatus according to claim 1,
A bypass passage provided in the flue so as to bypass the water vapor separation membrane,
A bypass damper provided in this bypass passage to control the amount of exhaust gas passing through,
The exhaust gas is further provided with a control device for adjusting the amount of water vapor separated by the water vapor separation membrane by controlling the amount of exhaust gas introduced into the water vapor separation membrane as needed by the bypass damper. Processing equipment. In the exhaust gas treatment apparatus according to claim 1 or 2.
Exhaust gas treatment apparatus characterized by further comprising a binary generator for generating electric power by utilizing the heat recovered in the previous SL heat exchanger. The temperature of the exhaust gas discharged from the waste incinerator is reduced by injecting cooling water with the exhaust gas cooling device, and the acidic gas in the reduced temperature exhaust gas is removed by the neutralizing agent supplied from the chemical supply device. It is an exhaust gas treatment method that removes soot and dust in the exhaust gas with a filtration type dust collector and releases this exhaust gas from the chimney to the atmosphere.
A water vapor separation process that separates water vapor in the exhaust gas that has passed through the filtration type dust collector with a water vapor separation membrane of a hollow fiber membrane.
A condensing treatment in which the separated steam is returned to water by the condensing device according to any one of claims 1 to 3.
An exhaust gas treatment method characterized by executing a recovered water reuse treatment in which the recovered water is reused as cooling water for the exhaust gas cooling device. In the exhaust gas treatment method according to claim 4,
The steam separation treatment is an exhaust gas treatment method characterized in that the separation amount of water vapor can be adjusted by controlling the amount of exhaust gas introduced into the water vapor separation membrane as needed. In the exhaust gas treatment method according to claim 4 or 5,
A method for treating exhaust gas, which comprises recovering the latent heat of steam separated by the steam separation treatment, and further executing a power generation treatment of using the recovered heat to generate electricity with a binary generator.

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