JPH05337331A - Exhaust gas treatment device - Google Patents

Abstract

PURPOSE:To make equipment compact. CONSTITUTION:The exhaust gas treatment device cools an exhaust gas from combustion equipment 1, then desulfurizes the cooled gas using a wet-type desulfurization device 7, and releases the exhaust gas after increasing its demperature. In addition, a saturator 6 which cools the exhaust gas through a direct contact with a cooling water and at the same time, renders the exhaust gas moisture-saturated, is provided in the upstream side of the wet-type desulfurization device 7. On the other hand, a humidity reduction cooler 8 which reduces the humidity of the exhaust gas after desulfurization and cools it is provided in the downstream side of the wet-type desulfurization device 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas treating apparatus for treating exhaust gas from combustion equipment such as a boiler.

[0002]

2. Description of the Related Art Gas discharged from a combustion equipment such as a boiler is high in temperature and contains impurities such as sulfur in the gas. Therefore, the gas is discharged to the atmosphere after being cooled and desulfurized by an exhaust gas treatment device. To be done.

As shown in FIG. 2, the exhaust gas treating apparatus includes an induction draft fan (IDF) 30 and a gas gas heater (GGA) 3.
1, wet desulfurization device 32, desulfurization exhaust gas blower (BUF) 3
3, the gas gas heater (GGA) 34 is mainly configured, and the exhaust gas from the boiler 35 is guided to the first gas gas heater 31 by the induced draft fan 30 and cooled. Then, it reaches the wet desulfurization device 32, where the exhaust gas and the absorbing liquid come into gas-liquid contact with each other, the sulfur content in the gas is absorbed and removed by the absorbing liquid, and the exhaust gas is desulfurized. The gas after the desulfurization treatment is guided to the second gas heater 34 by the desulfurization exhaust gas blower 33, and the temperature of the gas at about 50 ° C. is raised to about 90 ° C., for example. Then, the chimney 36 is opened to the atmosphere.

[0004]

By the way, in the above-mentioned exhaust gas treatment apparatus, since the exhaust gas treatment apparatus is composed of an induction fan, a gas gas heater, a wet desulfurization apparatus, a desulfurization exhaust gas fan, a gas gas heater, etc. It requires a large space for installing the device. In particular, the gas-gas heater is made large in size because the gas is indirectly contacted with the gas for heat exchange.

Therefore, the present invention has been made in consideration of such circumstances, and an object thereof is to provide an exhaust gas treating apparatus which enables downsizing of equipment.

[0006]

In order to achieve the above object, the present invention is an exhaust gas treatment in which exhaust gas from a combustion device is cooled, desulfurized by a wet desulfurization device, heated, and then opened to the atmosphere. In the apparatus, on the upstream side of the wet desulfurization apparatus, a saturator is provided to bring the exhaust gas into direct contact with cooling water to cool it and to bring it into a water-saturated state. A dehumidifying cooler for dehumidifying cooling is provided.

[0007]

The exhaust gas from the combustion equipment is directly contacted with the cooling water in the saturator to be cooled and saturated with water, and is introduced into the wet desulfurization device. As described above, since the exhaust gas is cooled by exchanging heat with the cooling water, the gas can be cooled more efficiently than the case where the gas is cooled by the gas, so that the equipment for cooling the gas can be downsized. Become. In addition, since the exhaust gas is saturated with water and guided to the wet desulfurization device, the amount of the absorbed liquid evaporated in the desulfurization device decreases. Therefore, exhaust gas can be sufficiently treated with a small amount of absorbing liquid, and the desulfurization device can be downsized. Furthermore, since the exhaust gas after desulfurization is cooled by the dehumidifying cooler,
It is possible to reduce the size of the device that raises the temperature of the exhaust gas to open it to the atmosphere. Therefore, the equipment can be made smaller than the conventional one.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 denotes a boiler as a combustion device, and a plant of this boiler 1 has cooling water (for example, seawater) that contributes to cooling a condenser (not shown), a turbine (not shown), and the like. 2) is provided.

An exhaust gas duct 4 for guiding the gas discharged from the boiler 1 to the chimney 3 is connected to the boiler 1, and the induction fan (IDF) 5, 5 is installed in the exhaust gas duct 4 along the gas flow direction. Saturator 6, wet desulfurization device (DeSO
x) 7, dehumidifying cooler 8 and steam gas heater (SG
H) 9 are sequentially provided.

The saturator 6 uses the duct 4 to form the main body 6a.
A spray nozzle 10 for spraying cooling water which is brought into direct contact with the exhaust gas to cool the exhaust gas and to bring it into a water saturated state is provided in the main body 6a. Further, a liquid reservoir 11 for storing the cooling water sprayed from the spray nozzle 10 is formed in the lower portion of the saturator body 6a so that the liquid in the liquid reservoir 11 is aerated by the air from the air pipe 12. It has become. Furthermore, the liquid reservoir 1
Pump 1 for transferring a part of the liquid in 1 to the spray nozzle 10.
A transfer pipe 14 with 3 is connected. The transfer pipe 1
Alternatively, air may be blown into the liquid flowing in the pipe 14 to perform the aeration treatment of the liquid. A seawater supply pipe 15 for supplying seawater is connected to the transfer pipe 14, and
The extraction pipe 16 for extracting a part of the liquid in the transfer pipe 14 is connected, and the cooling water sprayed from the spray nozzle 10 is
The supply amount and the extraction amount of seawater are appropriately controlled and adjusted according to the salt concentration in the cooling water. The extraction pipe 16 is connected to a wastewater treatment device 17, and the wastewater treatment device 17 is
A neutralization tank 18 for neutralizing the liquid from the extraction pipe 16 with calcium carbonate and the like, and a dehydrator 19 for separating and collecting solid contents such as gypsum contained in the liquid treated in the neutralization tank 18 are mainly included. The drainage pipe 20 of the drainage is constructed and is connected to the discharge pipe 2. A mist eliminator for removing mist may be provided between the saturator and the desulfurizer.

The desulfurization device 7 is of a wet type and is for desulfurizing the gas by bringing the exhaust gas into contact with an absorbing liquid containing calcium carbonate or the like to absorb and remove the sulfur content in the gas into the absorbing liquid. A makeup water supply pipe 21 for supplying makeup water is connected. A part of the makeup water may be supplied to the saturator.

The dehumidifying cooler 8 has a main body 8a formed by using a duct almost like the saturator 6 described above. The main body 8a is brought into direct contact with the exhaust gas so that the exhaust gas has a temperature of, for example, about 50.degree. A spray nozzle 22 for spraying cooling water (seawater) for partial condensation removal of vapor in the gas is provided. A seawater branch pipe 23 branched from the seawater supply pipe 15 is connected to the spray nozzle 22. In addition, a liquid reservoir 24 that stores the seawater sprayed from the spray nozzle 22 is formed in the lower portion of the dehumidifying cooler main body 8a, and a part of the liquid in the liquid reservoir 24 is stored in the liquid reservoir 24. A conduit 25 leading to the drainage pipe 20 is connected. The dehumidifying cooler 8 may be one that indirectly contacts the exhaust gas with the cooling water if the exhaust gas is cooled and the vapor in the gas is partially condensed and removed. When a wet type is used as the dehumidifying cooler 8, a mist eliminator or the like for removing mist may be provided between the dehumidifying cooler 8 and the steam gas heater 9.

The steam gas heater 9 heats the gas to, for example, about 60 to 70 ° C. by using steam (for example, low-pressure turbine extraction steam) that does not contribute to plant efficiency as a heat medium, and contributes to the temperature rise of the gas to condense it. The condensed water is collected in the condenser.

Next, the operation of this embodiment will be described.

Exhaust gas from the boiler 1 is exhausted from the exhaust gas duct 4
After entering and dedusting, it is guided to the saturator 6 by the induced draft fan 5, where it is directly contacted with the cooling water mainly composed of seawater sprayed from the spray nozzle 10 to be cooled and become saturated with water. .. Then, it flows into the wet desulfurization device 7,
There, desulfurization treatment is performed by contact with the absorbing liquid. The desulfurized gas is brought into direct contact with the spray liquid sprayed from the spray nozzle 22 in the dehumidifying cooler 8 to be cooled to, for example, about 50 ° C. to about 40 ° C., and the vapor in the gas is partially condensed and removed. Then, the steam gas heater 9 uses steam that does not contribute to plant efficiency (for example, low-pressure turbine extraction steam) to about 60 to 70 ° C.
After the temperature is raised to 1, the chimney 3 is opened to the atmosphere.

As described above, since the exhaust gas is discharged through the saturator 6, the desulfurizer 7, the dehumidifying cooler 8 and the steam gas heater 9, the equipment can be made much smaller than the conventional one. .. That is, since the saturator 6 on the upstream side of the desulfurization device 7 directly contacts the seawater and the exhaust gas to cool the exhaust gas and bring the water into a saturated state of water, the heat exchange rate is better than that in the case of exchanging heat between the gases. Therefore, the device for cooling the gas can be downsized as compared with the gas gas heater. Further, since the exhaust gas becomes saturated with water and is guided to the wet desulfurization device 7, the amount of evaporation of the absorption liquid in the desulfurization device 7 is reduced, and therefore the exhaust gas can be sufficiently treated with a small amount of absorption liquid. Therefore, the desulfurization device 7 can be downsized. Further, since the exhaust gas after desulfurization is cooled by the dehumidifying cooler 8 to reduce the moisture content in the gas, the temperature rise for discharging from the chimney 3 as compared with the conventional case. Since the amount is small and clear, the steam gas heater 9 can be downsized. Furthermore, since the saturator 6 for cooling the gas can be downsized, the pressure loss of the gas becomes smaller than that of the conventional one, so that the exhaust gas is discharged from the chimney without using the desulfurization exhaust gas ventilator (BUF). It becomes possible to do. Therefore, the equipment of the exhaust gas treatment device can be greatly reduced, and the cost can be reduced.

Further, since the exhaust gas comes into direct contact with seawater in the saturator 6, a minute amount of SO ₃ in the gas is absorbed and removed by seawater, so that corrosion by the acid on the downstream side can be prevented. The sulfuric acid content absorbed and removed by the seawater is neutralized with calcium carbonate in the neutralization tank 18 of the wastewater treatment device 17, and is recovered as gypsum by the dehydrator 19. Further, since the liquid in the liquid reservoir 11 of the saturator 6 is aerated by the air blown from the air pipe 12, it is forcibly oxidized,
COD in the liquid can be reduced.

Further, since the exhaust gas is saturated with water and guided to the wet desulfurization device 7, the amount of the absorbed liquid evaporated in the desulfurization device 7 is reduced. It can be reduced by about 20 to 30%. Therefore, it is effective in a place where there is little industrial water as makeup water.

Furthermore, since the moisture content in the gas of the exhaust gas is removed by the dehumidifying cooler 8, the proportion of the moisture content in the gas is reduced, so that white smoke can be suppressed when the chimney 3 is released into the atmosphere. It will be.

[0021]

In summary, according to the present invention, since the saturator is provided on the upstream side of the wet desulfurization apparatus and the dehumidifying cooler is provided on the downstream side of the wet desulfurization apparatus, the facility can be reduced. Exert an effect.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a conventional example.

[Explanation of symbols]

 1 Boiler (combustion equipment) 6 Saturator 7 Wet desulfurization device 8 Dehumidifying cooler

Claims (1)

[Claims] 1. In an exhaust gas treatment device for cooling exhaust gas from a combustion device, desulfurizing it in a wet desulfurization device, heating it, and then opening it to the atmosphere, the exhaust gas is cooled upstream of the wet desulfurization device. It is characterized in that a saturator for cooling the water by directly contacting with water and for saturating the water is provided, and a dehumidification cooler for dehumidifying and cooling the gas after desulfurization is provided downstream of the wet desulfurization device. Exhaust gas treatment device.