KR102131679B1 - Waste fluid treatment apparatus containing salt and method for treating same - Google Patents

Abstract

The present invention relates to an apparatus for treating waste liquid containing salts and a method for the same. The apparatus for treating waste liquid comprises: a waste liquid collector (10); a storage tank (20); a pH regulation unit (30); a buffer (40); a hot-air granulation unit (50); a granule capture unit (60); a dust collection unit (70); a catalytic oxidation combustion unit (80); an air-cooled heat exchanger (90); and a discharger (100). According to the present invention, dry powder granules crystallized in a solid state can be conveniently extracted.

Description

Waste fluid treatment apparatus containing salt and method for treating same

The present invention relates to an apparatus and a method for treating a salt contained in a waste solution, and more specifically, after collecting the waste solution containing the salt, adjusting the pH, molding it into a solid through an immobilization molding machine, and discharged during this process The odor gas relates to a waste liquid treatment apparatus and a treatment method comprising a salt that decomposes a nitrogen oxide through an SCR and removes sulfides from a desulfurization scrubber after decomposition by a catalyst layer and high temperature in a catalytic oxidizer.

In general, various organic or inorganic gases are generated in places such as sewage treatment plants, manure treatment plants, food processing facilities, and animal husbandry facilities to produce complex odors, and the resulting odors are complex due to their alkalinity, acidity, and neutrality. A single chemical cleaning solution such as a slow oxidizing agent has a characteristic that it is difficult to effectively treat malodorous gases.

As a method of removing the malodorous gas of the complex based on these characteristics, a number of nozzles are installed in the deodorization tower, and from this, the malodor is removed by contacting the gas containing the malodor introduced into the deodorization tower (water washing method) In addition, in addition, a method of placing an adsorbent layer such as activated carbon, silica gel, and Zelite in the deodorization column to adsorb malodorous substances (adsorption method), or by placing a specific microbial layer instead of the adsorbent, causes the microorganisms to generate malodor generating substances. There is a method of disintegration (microbial contact method).

As described above, the malodorous gas composed of the composite gas is usually purified by causing a neutralization reaction with an'acid and alkali' chemical solution, and such a normal deodorization tower has a slow reaction speed, which decreases efficiency, but reacts complexly with oxidizing agents (sodium hypochlorite, etc.). It consists of a single deodorizing tower or two deodorizing towers in series, each of which consists of an acid and alkali washing tower, which are connected in series. It had a problem that the installation space and installation cost were excessive due to the large size.

In order to improve this, Korean Patent Registration No. 10-0820845 (2-liquid simultaneous cleaning deodorization tower) (hereinafter referred to as'prior invention') has an acid and alkali washing tower as an integral deodorization tower, so that each cleaning liquid is circulated separately. In addition, while cleaning the complex gas, it is possible to downsize the device, while performing the two-stage cleaning of the jet nozzle and the pack bed even when cleaning the acid or alkali alone, as well as ensuring the excellent cleaning power as well as the simultaneous neutralization reaction of acid and alkali There is an effect that is formed to improve the deodorizing power.

However, in the preceding invention, there is a problem in that the pressure loss of the jet nozzle used for cleaning is large, and the bubbles being sprayed are large, resulting in poor cleaning efficiency, and further, no method for treating the sludge contained in the waste liquid is presented.

In general, leachate generated from waste treatment facilities and washing wheel waste water contain salts such as Nacl or Kcl. Conventionally, leachate is treated through complex treatment facilities such as degassing, DAF, biological treatment, filtration, and ozone oxidation. , Dewatering sludge is generated in a separate process to generate a dehydrated cake, and a by-product treatment process is to be re-embedded again, and a separate deodorization facility is essential to remove high-concentration odor generated in the process.

In order to improve this, a reduced pressure evaporation vessel (MVR) method was proposed to reclaim the dehydrated cake after dehydrating the evaporated residue evaporated with water vapor by lowering the breaking point. However, the reduced pressure evaporation method requires additional equipment for wastewater treatment of the gas that is not enclosed in the evaporated condensate, and requires periodic maintenance of the concentrator, resulting in a low facility operation rate.

Therefore, in order to solve this problem, the applicant of the present application applies Patent No. 10-2031920 (a first ammonium phosphate granule manufacturing apparatus and its manufacturing method to recycle ammonium phosphate waste liquid discharged from a semiconductor etching process) and includes it in the waste liquid In order to effectively treat the salt, it is intended to propose an apparatus and method capable of treating a waste solution containing a salt with improved processes and apparatus.

The present invention is to solve the problems as described above, after collecting the waste liquid to adjust the pH, molded into a solid through an immobilization molding machine, the odor gas discharged in this process is decomposed by high temperature and catalyst layer in the catalytic oxidizer After that, the object of the present invention is to provide a waste liquid treatment apparatus and a method for removing nitrogen oxides through an SCR and including a salt for removing sulfides from a desulfurization scrubber.

In addition, the present invention is a pre-treatment step (S10), aging step (S20), granule extraction step (S30), drying powder immobilization step (S40), selective catalyst reduction step (S50), gas discharge step (S60), sulfide There is another purpose in the waste liquid treatment apparatus and the treatment method containing the salt through a simple step-by-step process of the removal step (s70).

Waste liquid treatment apparatus comprising a salt according to the present invention is a waste liquid collector, a storage tank, a pH adjuster, a buffer, a hot air granulator, a granule collector, a filter dust collector, a catalytic oxidizer, an air-cooled heat exchanger, and an ejector The dry powder discharged from the granule collector is molded into a cement brick in the immobilization molding machine 110 and then moved to a landfill, and the gas that has passed through the filter dust collector and heat exchanger is SCR (Selective Catalytic) Nitrogen oxide is removed in the reduction, and the gas discharged from the discharger is characterized in that sulfide is removed by a desulfurization scrubber.

In addition, the method for treating a waste solution containing salt according to the present invention includes a pre-treatment step (S10) for adjusting the pH of the waste solution containing the collected salt, and a aging step (S20) of the mixed solution containing the adjusted component and drying at high temperature. The granules extraction step (S30), drying powder immobilization step (S40), selective catalytic reduction step (S50), and gas discharge step (S60) to crystallize the salts contained in the waste solution are sequentially performed, and the dried powder In the immobilization step (S40), the dry powder generated in the granulation extraction step is put into an immobilization molding machine, and the waste incineration ash or cement, a solidifying agent, and a certain amount of molding water are mixed to form a cement brick by high pressure press. , wherein the selective catalytic reduction step (S50) for the nitrogen oxide is first the primary treatment odor gas in a fabric filter in and remove the NO _x, the gas discharge step (S60) contained in the exhaust gas through the SCR (selective catalytic reduction) Another technical feature is that the catalytic oxidizer directly burns and catalytically decomposes at a high temperature to remove odor components and discharge clean gas through an exhaust.

According to the waste liquid treatment apparatus and the treatment method comprising the salt according to the present invention, after collecting the waste liquid and adjusting the pH, granules of dry powder crystallized in a solid state can be easily extracted through a hot air granulator and a filter dust collector. , This dry powder can be solidified into a cement brick and buried to prevent re-elution of contaminated water.

In addition, the residual gas components are directly burned and catalytically decomposed at high temperatures through a catalytic oxidizer to remove the odorous components, ammonia gas and acetic acid gas, and then remove nitrogen oxides and sulfides through SCR and desulfurization scrubbers to exchange heat with eco-friendly effects. It has the effect of recycling the waste heat through the gas.

1 is a block diagram of a waste liquid treatment apparatus comprising a salt according to the present invention,
Figure 2 is an embodiment of the present invention, the configuration of the waste liquid collector and storage tank,
3 is an embodiment of the present invention, the configuration of the buffer,
Figure 4 is an embodiment of the present invention, a schematic view showing a waste liquid treatment apparatus containing salt,
Figure 5 is a process step diagram showing a method for treating a waste solution containing a salt according to the present invention

A preferred embodiment of the present invention will be described in detail through the accompanying drawings.

As shown in FIG. 1, the waste liquid treatment apparatus including the salt according to the present invention collects leachate and performs a predetermined treatment process to collect a waste liquid collector 10, a storage tank 20, and a pH adjusting unit 30 ) And a buffer 40, a hot air granulator 50 and a granule collector 60 and a filter dust collector 70 are provided to extract granules of salt crystallized by hot air drying and pre-filter, clean gas In order to discharge (clean gas), a number of equipment devices including a catalytic oxidizer 80 and a heat exchanger 90 for recycling waste heat and an ejector 100 are linked.

In particular, the present invention is based on the technology applied in the patent application No. 10-2031920 of the applicant, immobilization molding machine (110) to form a dry powder into a cement brick to remove nitrogen oxides (NO _x) contained in the exhaust gas ), SCR (120: Selective Catalytic Reduction Device) for removing nitrogen oxides using a catalyst, and desulfurization scrubber 130 for removing sulfide (H ₂ S) using magnesium hydroxide (Mg(OH) ₂ ) It is equipped with a technical difference.

First, in the waste liquid collector 10, as shown by the process of'I' in FIG. 2, the waste liquid is collected by a dedicated transportation vehicle, and the waste liquid collected through the plurality of waste liquid collectors 10 is a storage tank. (20).

In order to adjust the pH of the storage tank 20, the pH adjusting unit 30 inputs an adjustment component composed of a certain amount of alkaline or acidic substances into the storage tank 20.

In one embodiment of the present invention, the pH adjusting unit 30 uses sodium hydroxide as an alkaline substance and sulfuric acid as an acidic substance to adjust the pH of the mixed liquid with the waste liquid to 6-7.

In addition, as shown in the process of'II' in FIG. 3, the mixed liquid in which the adjustment component is added to the waste liquid in the storage tank 20 is transferred to and stored in a plurality of buffers 40, and is aged by waiting for a certain period of time. .

This is because the mixed solution causes a sufficient chemical reaction, so that it is more efficiently solid crystallized during hot air drying, which will be described later, and is preferably aged for about 4 hours.

The mixed solution supplied from the buffer 40 is supplied from the heat exchanger 90 while spraying with ultrafine particles through an atomizer nozzle in the hot air granulator 50, as shown by the process of'III' in FIG. It is dried by a hot air of 150 to 600° C. and crystallized into a granular powder, and the solid crystallized granules are extracted with a granulator collector 60 provided at the bottom. At this time, the temperature of the hot hot air should be adjusted to the most desirable temperature according to the composition of the wastewater.

In addition, since the fine powder remains in the gas generated in the hot air drying (granulation) process, it is sent back to the filter dust collector 70, and the filter dust collector 70 is provided with granules, which are solid components, through the filter. It is extracted with a collector (60).

The granules, which are dry powder wastes extracted in the granulator collector 60, contain contaminants, salts, heavy metals, and solids contained in the leachate, and when these dry powder wastes are reclaimed in a landfill, they are redissolved within the landfill. It acts as a cause of increasing the degree of contamination of leachate.

Therefore, in the present invention, the dry powder is temporarily stored to mix the waste incineration ash (fly ash) or cement with a solidifying agent or hardener, and a certain amount of molding water in the immobilized molding machine 110 to prevent re-elution. The immobilization method, which is molded into a brick shape, is temporarily stored in a fixed brick curing and drying field, and then re-embedded into a landfill.

The fly ash (飛散灰) refers to ash or ash that is blown off during the combustion process or crushing process. In one embodiment of the present invention, slaked lime (消石灰) is used to neutralize the fly ash. , Slaked lime is a strong alkaline calcium hydroxide of the formula Ca(OH) ₂ that easily combines with carbon dioxide to produce calcium carbonate that does not dissolve in water, acts on ammonia salt to separate ammonia, and dissolves in acid to form calcium salt. It acts to neutralize the fly ash containing.

In particular, the immobilized brick of the present invention needs to be molded by regularly performing a dissolution test to control the mixing ratio of cement and solidifying agent.

Molding water is supplied to the forming water after storing the overflow water and exchanged water from the desulfurization scrubber 130, which is a wet scrubber facility for desulfurization, in the forming water storage tank. Since the molding water contains desulfurized sludge (MgSO ₄ ) produced by the scrubber, separate wastewater treatment is required, but it is used as molding water and re-embedded into a landfill to reduce wastewater treatment costs.

In the catalytic oxidation combustor 80, the odor gas generated in the hot air granulator 50 is catalytically decomposed to a high temperature of 450° C. or higher to remove odor components, and the clean gas from which the odor components have been removed is a heat exchanger (90). Is transferred to.

The heat exchanger 90 cools high-temperature gas by air-cooling, and heats the outside air at room temperature to about 300 to 350°C as waste heat of the gas to recycle the waste heat by transferring it to the hot air granulator 50. do.

The gas that has passed through the heat exchanger 90 is transferred to the SCR 120, and the cooled gas discharged from the gas/air heater contains dry moisture contained in leachate, NH ₃ -N, sulfide (H ₂ S), and the like. These pollutants should be purified before being discharged into the air to prevent environmental pollution.

The SCR (Selective Catalytic Reduction) 120 is for removing NO _x contained in the gas by using the principle of a selective catalytic reduction method, and a high concentration of TN (mostly NH ₃ -N) is contained in the leachate. Should be removed.

The principle of the selective catalytic reduction method to remove NO _x is as follows.

4NO + 4NH ₃ + O ₂ → 4N ₂ + 6H ₂ O

2NO ₂ + 4NH ₃ + O ₂ → 3N ₂ + 6H ₂ O

Here, NH ₃ is injected with urea water (Urea) as a liquid.

The catalyst of the SCR 120 is Fe ₂ O ₃ , Pt, CuO, WO _3, etc. as a metal oxide, and V ₂ O ₅ is mainly used as a vanadium system.

In one embodiment of the present invention, an economizer 91 may be additionally added to the rear end of the SCR 120, wherein the economizer 91 represents the largest portion of the heat loss of the boiler. As a device for preheating water supply using the heat of the flue gas occupied, it can be provided to a facility using hot water.

When high-temperature humid air meets low-temperature outside air, some moisture in the humid air is condensed to look like a cloud, and the economizer 91 reduces the absolute humidity by first removing moisture from the heat exchanger. It is a facility that reduces the relative humidity by mixing with high-temperature dry air before discharge, so that there is no occurrence of white smoke in the final state when mixed with ambient air.

The gas that has passed through the economizer 91 is discharged through a discharger 100 equipped with a chimney, and the chimney (煙突) is intended for ventilation flue gas and diffusion and dilution of exhaust gas by a combustion facility. As an accessory, in the present invention, a blower and a silencer are provided to effectively discharge clean gas without noise.

The gas discharged to the discharger 100 is transferred to a desulfurization scrubber 130, and in the desulfurization scrubber 130, magnesium hydroxide:Mg(OH) to remove sulfide (H ₂ S) finally remaining in the leachate in the gas. ) ₂ to remove.

The mechanism of desulfurization reaction is as follows.

Mg(OH) ₂ + SO ₂ → Mg ^{2 +} + MgSO ₃ + 2H ₂ O

The desulfurization scrubber 130 using magnesium hydroxide has an advantage of high purity of magnesium hydroxide, economical, ultra fine, no nozzle clogging, excellent reactivity, and no residue after reaction.

On the other hand, the method for treating waste liquid containing salt according to the present invention is performed by a step-by-step process as shown in FIG. 5.

First, the waste liquid is collected through the waste liquid collector (10) and stored in the storage tank (20), and contains a certain amount of alkaline or acidic substances through the pH adjusting unit (30) to adjust the pH of the waste liquid containing salt. The pre-treatment step (S10) of adjusting the pH to 6-7 by dropping the adjusted component is performed.

In one embodiment of the present invention, the pH adjusting unit 30 uses sodium hydroxide to adjust the pH of the waste solution. When the alkalinity is excessive, sulfuric acid is used again to finally adjust the pH of the mixed solution with the waste solution to 6-7. Is done.

Subsequently, the aging step (S20) in which the mixed solution, in which the adjustment component is added to the waste solution, is transferred to the plurality of buffers 40 and is dividedly stored to wait for a predetermined time.

In addition, while drying the matured mixed solution at 150 to 600° C. through hot air granulator 50 to extract the crystallized granules, transfer the primary gas to the filter dust collector 70, and extract the salt granules again through the filter. Granule generation step (S30) for discharging the secondary gas proceeds.

Subsequently, a dry powder immobilization step (S40) in which the granules composed of the dry powder is formed in a cement brick form by mixing waste incineration ash or cement with a solidifying agent and a certain amount of molding water in the immobilization molding machine 110 is performed.

Then, in the SCR 120, a selective catalytic reduction step (S50) of removing NO _x contained in a gas by using the principle of the selective catalytic reduction method is performed.

The odor gas discharged from the filter dust collector 70 is heated to a high temperature in a catalytic oxidizer 80 and oxidatively decomposed by a catalyst to remove the odor, and the hot gas from which the odor has been removed is passed through a heat exchanger 90. The gas discharge step (S40) of discharging clean gas to the outside through the discharger 100 while recycling waste heat is performed.

At this time, a high temperature and a catalytic reaction of 450° C. or more are carried out in the catalytic oxidizer 80, and the high temperature gas is cooled to about 300° C. or less in the heat exchanger 90 and transferred to the discharger 100.

The heat exchanger (90) is composed of air-cooled type by inhalation of outside air to cool the gas, and at the same time heat the air at room temperature to over 350°C by heat exchange to recycle the waste heat, and transfer it to the hot air granulator (50) to hot air It will be recycled to the hot temperature of the granulator 50.

Finally, in order to remove the sulfide (H ₂ S) finally remaining in the gas in the desulfurization scrubber 130, a sulfide removal step (S70) of removing by introducing Mg(OH) ₂ is performed.

10: waste liquid collector 20: storage tank
30: pH adjustment unit 40: buffer
50: hot air granulator 60: granule collector
70: filter dust collector 80: catalytic oxidizer
90: heat exchanger 91: economizer
100: ejector 110: immobilization molding machine
120: SCR 130: desulfurization scrubber

Claims (8)

Waste liquid collector (10), storage tank (20), pH adjuster (30), buffer (40), hot air granulator (50), granule collector (60), filter dust collector (70), It comprises a catalytic oxidation combustor 80, an air-cooled heat exchanger 90, and an ejector 100,
The dry powder discharged from the granule collector 60 is molded into a cement brick in the immobilization molding machine 110 and then moved to a landfill site to be buried.
The gas that has passed through the filter dust collector 70 and the heat exchanger 90 is nitrogen oxide is removed from the SCR (Selective Catalytic Reduction) 120,
In the discharger (100), a waste gas treatment device comprising a salt, characterized in that a clean gas from which sulfides have been removed by the desulfurization scrubber (130) is discharged.
According to claim 1,
The immobilization molding machine 110 is a waste liquid treatment device comprising a salt, characterized in that in the form of a cement brick by mixing waste incineration Ash or cement with a solidifying agent and molding water in a dry powder.
According to claim 2,
The forming water is a waste scrubber treatment device comprising a salt, characterized in that the desulfurization scrubber 130, which is a wet scrubber facility for desulfurization, stores the overflow water and the exchanged water flowing in the forming water storage tank and supplies it to the forming water storage tank.
According to claim 1,
The SCR 120 is a waste liquid treatment apparatus comprising a salt, characterized in that any one of Fe ₂ O ₃ , Pt, CuO, WO _3, V ₂ O ₅ is used as a catalyst.
According to claim 1,
The desulfurization scrubber 130 is Mg(OH) ₂ Waste liquid treatment apparatus comprising a salt, characterized in that to remove the sulfide using.
Pretreatment step (S10) to adjust the pH of the waste solution containing the collected salt, aging step (S20) of the mixed solution containing the adjusted component, and granulation extraction step (S30) to crystallize the salt contained in the waste solution by high temperature drying ), the drying powder immobilization step (S40), the selective catalyst reduction step (S50), and the gas discharge step (S60) sequentially proceeds,
In the step of immobilizing the dry powder (S40), the dry powder generated in the granular extraction step is introduced into the immobilization molding machine 110, and a mixture of waste incineration ash or cement, a solidifying agent, and a certain amount of molding water is mixed by high pressure press. Molded in the form of a cement brick,
In the selective catalytic reduction step (S50), and remove the nitrogen oxides NO _x contained in the exhaust gas through the SCR (Selective Catalytic Reduction) (120 ),
In the gas discharging step (S60), the malodorous gas first treated in the filter dust collector 70 is directly burned and catalytically decomposed to a high temperature in the catalytic oxidizer 80 to remove malodorous components and clean gas through the exhauster 100. (Clean gas) waste liquid treatment method comprising a salt characterized in that the discharge.
The method of claim 6,
In the selective catalyst reduction step (S50), the nitrogen oxide contained in the exhaust gas, NO _x , is catalyzed according to the principle of liquid urea water (Urea) and the selective catalyst reduction method, and characterized in that it is discharged by being harmless with N ₂ gas. Waste liquid treatment method comprising a salt.
The method of claim 6,
After the gas discharging step (S60), a salt characterized in that a sulfide removing step (S70) for adding and removing Mg(OH) ₂ to remove the sulfide finally remaining in the gas in the desulfurization scrubber 130 is added. Waste liquid treatment method comprising a.

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