KR900000751B1 - Treatment method of the exhast liquid in the wet-treatment apparatus of the exhast gas - Google Patents

Abstract

An exhasut gas is passed through a dry-type dust collector to remove a dust and then a wet-type gas treating apparatus to purify the exhaust gas. An exhaust liquid in the wet-type gas treating apparatus is poured from the up stream side of the collector to be contacted with the exhaust gas, and resulting solid matters are collected.

Description

Wastewater treatment method in a wet exhaust gas treatment system

1 is a conceptual diagram showing the configuration of one device for practicing the present invention.

2 is a flow chart of a wastewater reduction system in a wet exhaust gas treatment system.

3 is a conceptual diagram of a conventional apparatus corresponding to FIG.

The present invention relates to a method for treating wastewater in a wet exhaust gas treating apparatus. Since the wastewater in the conventional wet exhaust gas treatment system cannot be discharged as sewage or the like, this wastewater is further treated.

For example, a wastewater reduction system for injecting and treating this wastewater into the flue leading to the dust collector has been implemented, which will be described according to FIG.

The exhaust gas from the boiler 11 is led to the air heater 13 via the flue 12 and heat-exchanged with air, whereby the exhaust gas temperature is lowered. The exhaust gas exiting the air heater 13 is led to the dry electrostatic precipitator 2 by the flue 8. In this way, waste water is sprayed by the spray nozzle 1, and exhaust gas temperature falls.

In the dry electrostatic precipitator 2, solids produced by drying out the dust and the drainage in the exhaust gas are collected.

The collected solids are recovered by a collecting device 6 to a collecting collector (not shown).

Exhaust gas from the dry electrostatic precipitator 2 is led to the gas heater 15 via the flue 14, where the wet exhaust gas and treatment apparatus 17 includes sulfur dioxide in the exhaust gas and a dry electrostatic precipitator ( Collect and remove the unsold sold out again in 2). The exhaust gas from the wet exhaust gas treatment device 17 is led to the gas heater 15 via the flue 18 to be heat exchanged, and then to the stack 20 through the flue 19 to be discharged to the atmosphere. .

Drainage from the wet exhaust gas treatment system 17 is led to the neutralization tank 22 via the drain line 21. In the neutralization tank 22, slaked lime is introduced from the neutralizer line 23, and the drainage is neutralized. The neutralized drainage is led through the drain line 24 to the drainage spray nozzle 1 and sprayed into the flue 8.

In this drainage reduction system, the characteristic of the conventional structure from the nozzle 1 for drainage sprays to the dry electrostatic precipitator 2 is demonstrated by FIG.

2 is a dry electrostatic precipitator and is of a conventional structure. The spray nozzle 1 is provided in this electric current. The drainage sprayed from the spray nozzle 1 is evaporated to dryness in the flue 8, but a part of it is deposited in the flue as the flue deposit 7. Most of the dry solids 5 thereof are collected by the discharge electrode 3 and the dust collecting plate 4 in the dry electrostatic precipitator 2 and recovered by the collecting collector 6 installed in the lower part of the dust collector 2. do.

Here, the droplets in the spray nozzles require about 2 seconds of holding time in the exhaust gas to evaporate. The gas flow rate of one flue is usually 15-20 m / s, so that the required flue length is about 30-40 m and expands. If the gas flow rate is slowed, soot will accumulate in the year.

The present invention eliminates the drawbacks of the conventional method of treating wastewater and reduces the dust collection efficiency of the electrostatic precipitator even if the length of the flue from the spray nozzle to the electrostatic precipitator is shorter, for example, about 10 m or less, without causing a decrease in the exhaust gas treating apparatus. To provide a treatment method.

Summary of the Invention The present invention leads the exhaust gas to the dry dust collector, removes the dust contained in the exhaust gas, and then directs it to the wet exhaust gas treatment device to purify the exhaust gas and discharge the exhaust gas from the exhaust gas treatment device. In the wastewater treatment method which injects from the upstream of a dry dust collector, and collects the dry solid matter in the said dry dust collector, the 1st chamber of a dry dust collector is made into empty space, and the empty space is provided in the front of a dry dust collector, A method of treating wastewater in an exhaust gas treating apparatus, wherein the waste gas of the exhaust gas treating apparatus is sprayed with the flue in the current flue.

That is, according to the present invention, the first chamber of the dry dust collector is set to a vacancy or the dry dust collector in order to prevent the accumulation of the dust generated when the flow rate of the sprayed droplets is retained in the exhaust gas while slowing the flow rate of the exhaust gas. It is characterized by treating the exhaust gas by installing a vacancy in front of the.

Hereinafter, it demonstrates concretely based on an accompanying drawing.

1 shows one device configuration for practicing the present invention. 1 is a spray nozzle for drainage of the exhaust gas treating apparatus. 2 is a dry electrostatic precipitator, and the spray nozzle 1 is provided in the electric current. Drainage sprayed from the spray nozzle 1 is dried in the flue 8 and the vacancy 9 of the first chamber of the dry electrostatic precipitator, and the solids 10 are collected and transported under the first vacancy 9. By the apparatus 6, it is collect | recovered by the collection collector (not shown) with the dust collector 5 collected in the 2nd and 3rd chambers of a dry electrostatic precipitator.

According to the researches of the present inventors, the exhaust gas temperature can be set to the temperature at which the dust collection rate is increased by spraying the waste liquid in the electrostatic precipitator, and the dry solids in the waste liquid such as sodium, calcium, magnesium, etc. are attached to the dust collecting plate. The increase in dust collection efficiency due to the electrical conductivity is divided.

Therefore, by selecting the amount of discharged liquid to spray and its composition, dust collection efficiency is raised, and even if a 1st room is made into a vacancy, the dust collection efficiency does not fall.

Next, a comparative example and an Example are demonstrated.

[Comparative example (conventional example)]

The conventional method was implemented using the pilot plant of the sun of FIG. 3 which can process 4,000 Nm3 / H of coal dust exhaust gas. The properties of the exhaust gas are shown in Table 1.

TABLE 1

Pilot plant emissions

The drainage is led from the wet exhaust gas treatment apparatus 17 to the neutralization tank 22 via the drain line 21 as 20 l / H. In the neutralization tank 22, 100 wt% of the slaked lime slurry is supplied as 5 l / H. The composition of the neutralization tank slurry is shown in Table 2. The wastewater after the treatment was sprayed from the spray nozzle 1 in the flue 8 at a rate of 25 l / H.

TABLE 2

Neutralization tank slurry composition

The length from the nozzle to the electrostatic precipitator is 40 m. The deposition of deposits in the year 8 is carried out at a reverse speed operation for one month, and has a deposition amount of about 40 Kg. The damping rate in the electrostatic precipitator was 95%. The electrostatic precipitator is comprised as 1st, 2nd, 3rd chamber like FIG.

EXAMPLE

The spray nozzle 1 for drainage is installed in the position of 10 m of electrostatic precipitators. The discharge electrode and the dust collecting plate of the first chamber of the electrostatic precipitator were removed to make a vacancy. As shown in Table 1, the characteristics of the exhaust gas were all oriental in comparison with the comparative example.

20 l / H of drainage was led from the wet exhaust gas treatment apparatus 17 via the drain line 21 to the neutralization tank 22, and 10 wt% of the slaked lime slurry was supplied as 5 l / H to the neutralization tank 22. The composition of the neutralization tank slurry is shown in Table 2.

25 L / H of treatment wastewater was distributed in the flue 8 from the spray nozzle. The deposition of deposits in the year 8 was not performed at all after one month of continuous operation. The damping rate in the electrostatic precipitator was 95%.

As described above, in the present invention, even if the length from the nozzle to the electrostatic precipitator is 10 m, which is one quarter of the comparative example, the same value is shown in the dust removal rate of the electrostatic precipitator, and the adherent deposit during the year is continuous for one month. As a result of the operation, a difference of about 40 Kg in the comparative example was found to be extremely remarkable, which was not present in this example.

The present invention has the following effects by adopting the above configuration.

1. It is possible to shorten the length of the year required for the evaporation of drainage.

2. There is no deposition of deposits in the year, and the reliability and operation rate of the wastewater reduction system are high.

3. Even if the first chamber of the dry electrostatic precipitator is empty, the collection effect of the dust is not reduced.

Claims (1)

The exhaust gas is led to a dry dust collector to remove the dust contained in the exhaust gas. The exhaust gas is passed to a wet exhaust gas treatment device to purify the exhaust gas, and the exhaust gas from the exhaust gas treatment device is discharged from the upstream of the dry dust collector. In the wastewater treatment method for injecting and collecting the dry solid matter in the dry dust collector, the first chamber of the dry dust collector is used as a vacancy, and the waste gas of the exhaust gas treatment device is sprayed from the current flue to the flue. A method for treating wastewater in an exhaust gas treating apparatus, characterized by the above-mentioned.

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