KR101751207B1 - Double stage wet scrubbing de-sulfurization apparatus and process using liquid fertilizer at bio gas plant - Google Patents

Abstract

The present invention relates to a wet desulfurization apparatus using a slurry in a biogas plant and a method of desulfurizing the same, and more particularly, to an apparatus and a method for desulfurizing a slurry produced by a biogas plant producing an anaerobic digestion tank, (NH ₄ OH) dissolved in liquid fertilizer to more effectively remove the impurities of hydrogen sulfide (H ₂ S) contained in the biogas. The present invention relates to a method for producing a biogas- And a two-stage desulfurization scrubber are arranged in series to control the operation of the first stage desulfurization scrubber alone. In addition, the first stage desulfurization scrubber and the second stage desulfurization scrubber are configured and arranged so that they can operate and control each other organically. utilization of ammonium hydroxide (NH ₄ OH) of the liquid manure that is stored in the storage tank to the process water and the reaction Within the hydrogen sulfide biogas (H ₂ S) and carbon dioxide (CO ₂₎ with hydrogen sulfide, ammonium under (a) due to _{(NH 4 HS), (b} ) ammonium carbonate _{((NH 4) 2 CO 3} ) and induce the same response in the Thereby reducing the amount of chemical agent required to perform an economical desulfurization process.
_{H 2 S + NH 4 OH →} NH 4 HS + H 2 O --- (a), CO 2 + 2NH 4 OH → (NH 4) 2 CO 3 + H 2 O --- (b)

Description

TECHNICAL FIELD The present invention relates to a wet desulfurization apparatus using a liquid biogas plant and a desulfurization apparatus using the same,

[0001] The present invention relates to a wet desulfurization apparatus and a desulfurization method thereof using a liquid pot in a biogas plant, and more particularly to a wet desulfurization apparatus and a desulfurization method using the same, By using ammonium hydroxide (NH ₄ OH) dissolved in liquid fertilizer to more effectively remove impurities from hydrogen sulfide (H ₂ S) contained in the biogas produced in the gas plant, existing chemical agents (NaOH ) or it can be relatively greatly reduce the chemicals consumption compared to wet chemicals desulfurization apparatus using a ferrous chloride (FeCl ₂₎ aqueous solution) provide an environment-friendly and economical desulfurization systems, as well as, after the removal of hydrogen sulphide (H ₂ S) Slurry Yuan securing fertilizer components such as (ammonium _{sulfate, (NH 4) 2 SO 4} ) , and at the same time ammonia odor Wet desulfurization device using the liquid manure in biogas plants that can give away the stench can be used for biogas preparation and relates to the desulfurization process.

As the industry becomes more sophisticated and human life becomes rich, the problem of treatment of high concentration organic wastes such as livestock manure and food wastes is seriously arising, and the renewable energy source is being secured through anaerobic fermentation for such treatment.

The above methane gas production technology by the anaerobic fermentation has already been established and popularized in Europe and Japan. It is a technology that not only has an environmental function of treating highly concentrated organic wastes (livestock manure, food waste, agricultural byproducts) (New and renewable energy) production function and fermented organic wastes, it is a technology that can achieve the natural cyclical function through the reduction of agricultural land.

As such, biogas is a renewable energy that can be used continuously and practically without restriction of environment and time.

The biogas is obtained by anaerobic digestion of organic waste having a high content of biomass such as livestock manure, food waste, food / drinking-water factory sludge, and sewage sludge. Biogas can be obtained from the landfill, and organic wastes, which are biogas raw materials, are continuously generated through human activities and various industrial activities.

The biogas is obtained by digesting organic wastes containing a large amount of organic substances under an anaerobic condition in which no oxygen exists and at a middle temperature (38 ° C) or a high temperature (52 ° C) For example, 50 to 75 vol.% Of methane (CH ₄ ), 25 to 45 vol.% Of carbon dioxide (CO ₂ ), 2,000 to 3,000 of hydrogen sulfide (H ₂ S) (CH ₄ ) and carbon dioxide (CO ₂ ) are the main components, and a small amount of hydrogen sulfide (H ₂ S), ammonia (NH ₃ ) And so on.

As such, the biogas can be a good energy source because of its high methane content. As a result, the biogas can be used in all customers using natural gas only after a moderate level of modification.

For example, biogas can be used as a fuel for heating, heating, power generation, or as a fuel for city gas or automobile fuel through refining, and can be used as a fuel for a gas engine cogeneration power generator or a micro gas turbine Thereby obtaining electric and thermal energy.

However, since the hydrogen sulfide (H ₂ S) of the biogas generated from the wastewater in the anaerobic digestion tank is generated by sulfur-reducing bacteria that reduce sulfur and sulfate, if the hydrogen sulfide is exposed to the human body, However, in the utilization process of biogas such as cogeneration power generation, it is converted to sulfurous acid gas and sulfuric acid to corrode boilers, engine cylinders and exhaust pipes, and adversely affect facilities and the environment such as pollution of the atmosphere due to sulfur oxides discharge.

As described above, the hydrogen sulfide (H ₂ S) is an impurity that must be removed because it causes malodor and corrosion in various processes and process piping, and causes catalyst poison when the fuel cell is operated.

Therefore, the sulfur component contained in the hydrogen sulfide must be removed from the biogas, and various desulfurization apparatuses or systems have been developed and operated according to the necessity of removing the sulfur component contained in the hydrogen sulfide as described above.

Conventional desulfurization apparatuses include a dry desulfurization apparatus, a wet chemical desulfurization apparatus, and a biological (microbial) desulfurization apparatus.

Firstly, the dry desulfurization apparatus is a method of adsorbing and removing a sulfur component by a chemical treatment on the surface of a solid adsorbent, and adsorbing and removing a sulfur component with an adsorbent such as activated carbon, silica gel, zeolite or the like.

The wet chemical desulfurization device utilizes a chemical reaction such as neutralization reaction or oxidation reaction by contacting biogas with a chemical liquid. The chemical liquid such as potassium carbonate (potassium carbonate), sodium hydroxide, and ferric chloride aqueous solution The sulfur component is chemically absorbed by contacting the biogas, or the sulfur component is physically absorbed to polyethylene glycol, methanol, and water.

However, there is a certain limit to the treatment of recent biogas in which the concentration of sulfur reaches 1,500 ppm to 10,000 ppm (2,250 to 3,000 mg / m 3) in this manner.

Accordingly, a biogas biological desulfurization system has been developed which overcomes the limitations of the conventional desulfurization apparatus and removes hydrogen sulfide containing sulfur components contained in the biogas by using thiobarbituric acid, a sulfuric acid bacterium.

As described above, the hydrogen sulfide (H ₂ S) desulfurization apparatus included in the biogas has many methods such as dry desulfurization, wet chemical desulfurization, microbial desulfurization and the like. However, since dry desulfurization has high replacement cost of dry desulfurization filter medium, Desulfurization is possible by the reaction with microorganisms by blowing air into the gas. However, since the nitrogen component in the air remains, the concentration of methane gas is lowered and it is not economical to solidify the methane gas. Desulfurization of wet chemical and high hydrogen sulfide concentration And the problem was exposed in terms of economical efficiency and environmental friendliness.

Among the many desulfurization methods such as dry desulfurization, wet chemical desulfurization, microbial desulfurization and the like, technologies relating to desulfurization of wet chemical are disclosed in the following Patent Documents.

For example, a technology related to a wet desulfurization apparatus is disclosed in Korean Patent Registration No. 0954230 (published on Apr. 21, 2010).

The wet desulfurization apparatus includes a pretreatment catalyst active tower having a first desulfurization methane gas outlet and a nozzle section at an upper end and a methane gas inlet through which methane gas flows, Wherein a primary desulfurization methane gas inlet for receiving a primary desulfurization methane gas through the outlet is provided in the upper part of the main catalytic active catalyst layer provided below the polyurethane foam layer, tower; A catalyst regeneration tower provided with means for receiving outside air through the exhaust manifold and the venturi injector and supplying the regenerated catalyst liquid to the nozzle unit, respectively; And a hydrogen peroxide tank provided with means for supplying hydrogen peroxide to the catalyst regeneration tower, wherein the pretreatment catalyst active top is provided with a nozzle And the main catalyst active tower is provided with means for transporting the regenerated catalyst liquid stored in the storage space provided under the inlet of the primary desulfurization methane gas to the catalyst regeneration tower .

The patent document discloses that a porous limestone layer (CaCO ₃ ) is provided in a pretreatment catalyst active tower and sulfur dioxide (SO ₂ ) contained in the effluent discharged to the pretreatment catalyst active tower in the catalyst regenerator causes the limestone layer to contain calcium oxide ) And carbon dioxide (CO ₂ ), and the calcium oxide acts as a cocatalyst so that iron (Fe) as a main catalyst separates sulfur in the methane gas introduced into the pretreatment catalyst active tower (CaSO ₄ ), which is a mixture of a limestone layer and sulfur dioxide in a pretreatment catalyst active tower, and a catalyst before and after regeneration is mixed with the regeneration catalyst, so that sulfur is removed from the methane gas The efficiency of the catalyst is lowered and the problem of degradation of the activity of the catalyst due to the organic substances contained in the introduced methane gas Technically it relates to a feature.

In addition, Korean Patent Registration No. 1465140 (published on November 25, 2014) discloses a technique relating to a biogas desulfurization system.

The biogas desulfurization system comprises a primary treatment tank for receiving biogas and contacting the treated water with caustic soda water for primary treatment and a primary treatment gas discharged from the primary treatment tank for receiving caustic soda and sodium hypochlorite treated water , A caustic soda supply device for supplying caustic soda to the primary and secondary treatment tanks, a sodium hypochlorite supply device for supplying sodium hypochlorite to the secondary treatment tanks, primary and secondary tanks A water supply device for supplying water to the car treatment tank, and a control unit for maintaining the pH of the primary and secondary treatment tank.

In the biogas desulfurization system, about 70% of the hydrogen sulfide contained in the biogas is removed using caustic soda in the first stage, and hydrogen sulfide untreated in the first stage is mixed with caustic soda and sodium hypochlorite in the second stage, Can be removed by 99% or more.

On the other hand, in the conventional wet chemical desulfurization system in which sodium hydroxide (NaOH) or ferrous chloride (FeCl ₂ ) aqueous solution is mixed with water and used as process reaction water, as shown in FIG. 1, The water contained in the lower reservoir 2 is supplied to the injection nozzle unit (not shown) inside the upper part of the desulfurization scrubber 1 using a supply pump 8, 3) to be sprayed.

At this time, any one of sodium hydroxide (NaOH) or ferrous chloride (FeCl ₂ ) aqueous solution stored in the chemical storage tank (7) is supplied to the piping connected to the injection nozzle unit (3) And can act as a process reaction channel capable of causing a chemical reaction for desulfurization.

The biogas supplied in the direction opposite to the flow of the process water is introduced into the desulfurization scrubber 1 through the gas inlet 5 provided at the lower end of the desulfurization scrubber 1, And the chemical gas such as sodium hydroxide or an aqueous ferrous chloride solution injected from the injection nozzle unit 3 passes through the packing media layer 4 filled with a plurality of rolls And the desulfurization process was caused by the chemical reaction with the process water.

After the biogas and the process water react with each other in the packing media layer 4 and the desulfurization by the chemical reaction occurs, the process water drops naturally and is accommodated in the lower reservoir 2 and then repeatedly supplied by the supply pump 8 And is continuously mixed with a chemical agent such as sodium hydroxide or ferric chloride aqueous solution sent from the chemical storage tank 7 in the course of this process so as to be repeatedly injected with the process reaction water do.

When the desulfurization concentration is analyzed through the analyzer and the concentration of the biogas after completion of the desulfurization reaction is reached to a predetermined reference value or less, the biogas is sent through the gas outlet 6 provided at the upper end of the desulfurization scrubber 1 to a consumer or a separate storage tank .

However, in the case of the conventional wet chemical desulfurization system shown in FIG. 1, consumption of chemical agents such as sodium hydroxide and ferrous chloride aqueous solution is excessive, which is problematic from the viewpoints of economy and environmental friendliness.

Korean Registered Patent No. 0954230 (Apr. 21, 2010, name: Wet Desulfurization Apparatus) Korean Patent Publication No. 1465140 (entitled "Biogas Desulfurization System", Nov. 25, 2014)

Accordingly, in the conventional desulfurization of the hydrogen sulfide contained in the biogas in the conventional biogas plant, when the conventional wet chemical desulfurization system is applied, a chemical agent (sodium hydroxide (NaOH) or ferrous chloride (FeCl ₂ ) aqueous solution) The present invention provides a method of circulating and spraying liquid without causing a decrease in the concentration of methane gas in the biogas so that the liquid can be circulated and sprayed without using a conventional chemical agent (or as much as possible) (Double Stage Wet Scrubbing De-Sulfurization System) for the removal of hydrogen sulfide (H ₂ S) economically.

That is, an object of the present invention is to provide a method for treating organic wastes such as livestock manure, food waste, and the like by operating an anaerobic digestion tank to remove impurities of hydrogen sulfide (H ₂ S) contained in biogas produced from a biogas plant (NH ₄ OH) dissolved in liquid fertilizer (liquid fertilizer) in order to more effectively remove toxic chemicals, compared with wet chemical desulfurizers using existing chemical agents, (NH ₄ ) ₂ SO ₄ ) in liquid fertilizer after the removal of hydrogen sulfide (H ₂ S), and also to remove odor such as ammonia odor A desulfurization apparatus using a liquid and a desulfurization method thereof in a biogas plant that can be used for biogas pretreatment There used to the ball.

According to an aspect of the present invention, there is provided a biogas plant for anaerobic digestion of organic wastes comprising livestock manure, the biogas produced by the biogas plant is introduced through a first gas inlet, A liquid waste containing ammonium hydroxide (NH ₄ OH) contained in the first lower reservoir is pumped upward through the first injection pump on the first injection pipe and is injected by the first injection nozzle part, The desulfurization reaction occurs in contact with the biogas in the first packing media layer located below the nozzle unit, and the biogas that has been reacted is discharged through the first gas outlet on the upper side, and the reacted liquid is discharged to the first lower reservoir A first-stage desulfurization scrubber having a configuration capable of being discharged to a separate second liquid storage tank after being collected, and a second- To the emission of biogas is being introduced through the second gas inlet via the gas pipe, the on ammonium hydroxide (NH ₄ OH) 2 injection a manure pipe including housed in the second lower reservoir at the bottom of the second gas inlet The liquid is pumped upward by the second injection pump and is sprayed by the second injection nozzle part, and the liquid is contacted with the biogas in the second packing media layer located below the second injection nozzle part, so that the desulfurization reaction occurs, The reacted biogas is discharged to the gas discharge pipe through the second gas outlet on the upper side and the reacted liquid is collected in the second lower reservoir and sent to the first lower reservoir through the process reaction water transfer pipe. A desulfurization scrubber and a liquid feed supply pump having a liquid feed pump and a filter unit so that the liquid feed can be filtered and sent into the second bottom storage tank of the two- And a first slurry storage tank in which a slurry containing ammonium hydroxide (NH ₄ OH) connected to the second slurry reservoir by a pipe is stored is provided.

According to the present invention, a concentration analyzer capable of analyzing and detecting the desulfurization concentration in the biogas is provided on the gas pipe, and the biogas can be opened and closed in accordance with a result of the desulfurization concentration analysis of the concentration analyzer, And a bypass gas pipe is provided on the gas pipe.

In addition, according to the present invention, any one of sodium hydroxide or aqueous ferrous chloride solution connected to the second injection pipe by the chemical liquid supply pipe equipped with the chemical liquid supply pump so as to supply process reaction water, which is a chemical agent, into the second injection pipe A chemical storage tank in which a chemical agent is stored, is characterized in that the chemical agent such as sodium hydroxide or an aqueous ferrous chloride solution is supplementarily used in the process water for performing desulfurization.

According to the present invention, in the wet desulfurization scrubber, the process reaction water is injected from the upper part through the injection nozzle part, the biogas generated from the biogas plant is introduced from the lower part, and the process reaction water and the biogas The method for desulfurizing a wet desulfurization apparatus according to claim 1, wherein the desulfurization reaction is carried out in the presence of the reaction gas, and the reaction gas is discharged to the outside, A desulfurization method of a wet desulfurization apparatus using an accessory is provided in a biogas plant, wherein a slurry containing ammonium hydroxide (NH ₄ OH) is used.

According to the present invention, in the state that the desulfurization scrubber is composed of a first-stage desulfurization scrubber and a second-stage desulfurization scrubber, which are arranged in series in a two-stage desulfurization scrubber, The liquid is introduced into the second lower reservoir of the desulfurization scrubber, and the thus introduced liquid ratio is sent to the upper second injection nozzle through the second injection pump on the second injection pipe, The slurry coming down to the lower reservoir is introduced into the first lower reservoir at the lower end of the first-stage desulfurization scrubber through the process reaction water transfer pipe, and the first and second reservoirs And is collected in the first lower reservoir through the first packing media layer as it is injected into the upper first injection nozzle through the injection pump. Then, the reacted liquid is supplied to the second liquid storage tank My is, the biogas is a first packing medium layer in a hydrogen sulfide (H ₂ S) biogas goes through as the first-stage inlet to a desulfurizing scrubber below the first gas inlet of the liquid ratio of the ammonium hydroxide (NH ₄ OH) and the reaction And the concentration of hydrogen sulfide is firstly reduced. The biogas is discharged from the first gas discharge port on the first-stage desulfurization scrubber through a gas pipe connected to the second gas discharge inlet below the second-stage desulfurization scrubber, Wherein the biogas is reacted with ammonium hydroxide in the liquid mixture flowing through the packed media layer to remove the second hydrogen sulfide, and then the biogas is discharged through a gas discharge pipe provided in the upper part of the second-stage desulfurization scrubber. A desulfurization method of a wet desulfurization apparatus using liquid fertilizer is provided.

According to the present invention, the desulfurization concentration of the biogas desulfurized in the first-stage desulfurization scrubber is analyzed through a concentration analyzer provided on the gas pipeline, and then the desulfurization concentration of the biogas is adjusted to a predetermined value or less The biogas is sent to the gas discharge pipe through a bypass gas pipe connecting the gas pipe and the gas discharge pipe without sending the biogas into the second stage desulfurization scrubber.

According to the present invention, the desulfurization concentration in the biogas discharged to the gas discharge pipe is analyzed and detected. When the desulfurization concentration is higher than the target concentration, any one of sodium hydroxide (NaOH) and ferrous chloride (FeCl ₂ ) Is supplied into the second injection pipe of the second-stage desulfurization scrubber and injected through the second injection nozzle part together with the liquid ratio flowing along the second injection pipe to contact with the biogas to cause a desulfurization reaction.

According to the invention, the animal waste to energy plant in a biogas plant for utilizing ammonium hydroxide (NH ₄ OH), which is dissolved in the liquid ratio to significantly reduce the amount of chemicals in order to operate in an environmentally sound and cost effective hydrogen sulfide (H ₂ S) from the surface of the substrate.

That is, in the present invention, in a biogas plant for anaerobic digestion of organic wastes such as livestock manure, ammonia in liquid fertilizer (liquid fertilizer) is absorbed into water (NH ₃ + H ₂ O → NH ₄ OH) of ammonium hydroxide in the liquid manure that is stored in the manure storage tank (NH ₄ OH) to hydrogen sulfide, ammonium under (a) by using a number of processes the reaction due to the biogas in a hydrogen sulfide (H ₂ S) and carbon dioxide (CO ₂₎ (NH ₄ HS) and ammonium carbonate ((NH ₄ ) ₂ CO ₃ ) in (b), thereby reducing the amount of the chemical agent required to perform an economical desulfurization process.

H ₂ S + NH ₄ OH -> NH ₄ HS + H ₂ O --- (a)

CO ₂ + 2 NH ₄ OH → (NH ₄ ) ₂ CO ₃ + H ₂ O --- (b)

Here, when the ammonium bicarbonate ((NH ₄ ) ₂ CO ₃ ) form is present in the solution by the reaction (b), the alkaline degree is maintained at a high level so as to buffer the pH.

Furthermore, according to the invention, chemicals for the desulfurization (sodium hydroxide (NaOH) or ferrous chloride (FeCl ₂₎ aqueous solution) economical environmentally friendly desulfurization of that requirement is not present or if it can be prevented to more economical and environmental pollution it to a minimum After the removal of hydrogen sulphide (H ₂ S), a fertilizer component such as ammonium sulfate (yuan, (NH ₄ ) ₂ SO ₄ ) is secured in the liquid by the following chemical reaction during the aeration process in the liquid storage tank and ammonia odor It has the effect of eliminating odor such as odor.

NH ₄ HS + 3O ₂ + H ₂ O ---> NH ₄ + HS + HO + H ₂ O + O ₂

---> SO ₂ + H ₂ O → H ₂ SO ₃ + H ₂ O

---> 2H ₂ SO ₃ + O ₂ → 2H ₂ SO ₄ + H ₂ O

---> 2NH ₃ + H ₂ SO ₄ + H ₂ O → (NH ₄ ) ₂ SO ₄ + H ₂ O

In other words, it is known that the sulfur component contained in the organic liquid fertilizer plays a role in increasing the taste and flavor inherent to the crop. In particular, in the crops such as watermelon, the sulfur (ammonium sulfate, (NH ₄ ) ₂ SO ₄₎ It is to secure a fertilizer component such as hydrogen sulphide, ammonium ₂ SO ₄₎ (NH ₄ HS), ammonium sulfate (ammonium sulfate, (NH ₄ through) contained in the liquid manure in the desulfurization process of randomly situation with the case of fertilization the fertilizer liquid ratio It is effective to increase the functionality of the.

Particularly, according to the present invention, when the desulfurization reaction is lowered due to the low concentration of ammonium hydroxide (NH ₄ OH) in the liquid fertilizer, the desulfurization system is made so as to add a chemical liquid such as sodium hydroxide (NaOH) sodium (NaOH) If this is added to liquid ratio entering the second stage desulfurization scrubber biogas and the reaction, hydrogen sulfide in ammonium hydroxide (NH ₄ OH) and biogas contained in the liquid ratio (H ₂ S) and carbon dioxide (CO ₂₎ (NH ₄ ) ₂ CO ₃ ) of the ammonium hydrogen sulfide (NH ₄ HS) and the ammonium hydrogen sulfate (NH ₄ HS) of the above-mentioned (a), and the reaction of hydrogen sulfide (H ₂ S) (NaOH) and (2) sodium carbonate (Na ₂ CO ₃ ) reactions occur at the same time due to (CO ₂ ), and the desulfurization function is performed simultaneously. The sodium hydroxide (NaOH) Lt; RTI ID = 0.0 > sodium hydroxide < / RTI > Compared to the use in a large amount it can be expected an effect to the amount of sodium hydroxide reduced by over 40%.

H ₂ S + NaOH → NaHS + H ₂ O --------- (1)

CO ₂ + ₂ NaOH - > Na ₂ CO ₃ + H ₂ O - (2)

Among the products reacted in the two-stage desulfurization scrubber, an aqueous solution of sodium carbonate (Na ₂ CO ₃ , soda) is introduced into the first-stage desulfurization scrubber, then injected into the first stage of the first-stage desulfurization scrubber, The desulfurization is carried out in the form of sodium hydrogen sulfide (NaHS) and sodium hydrogencarbonate (NaHCO ₃ ) in reaction (3) with the hydrogen sulfide contained in the biogas.

H ₂ S + Na ₂ CO ₃ -> NaHS + NaHCO ₃ - (3)

In addition, according to the present invention, the first stage desulfurization scrubber and the second stage desulfurization scrubber, which are designed in two stages, are arranged in series so that the operation control can be performed solely by the first stage desulfurization scrubber and the first stage desulfurization scrubber and the second stage desulfurization scrubber It is possible to efficiently select the operation mode by selectively operating one or two stages depending on the progress of the operation.

In particular, the two-stage wet desulfurization scrubber apparatus according to the present invention significantly reduces the consumption of sodium hydroxide by the desulfurization reaction in step 2 even when sodium hydroxide is used, thereby reducing drug consumption and cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 schematically shows the construction of a conventional wet chemical desulfurizer according to the prior art; FIG.
2 is a process flow diagram schematically showing the overall configuration of a two-stage wet desulfurization apparatus using a liquid and a chemical agent according to the present invention.
3 is a schematic view showing a mutual arrangement relationship between a first stage desulfurization scrubber and a second stage desulfurization scrubber of a two-stage wet desulfurization apparatus using liquid fertilizer and chemicals according to the present invention.
FIG. 4 is a schematic view showing the configuration of a chemical supply tank and a control unit applied to a two-stage wet desulfurization apparatus using liquid fertilizer and chemicals according to the present invention. FIG.
FIG. 5 is a schematic plan view showing a mutual arrangement relationship between a first stage desulfurization scrubber, a second stage desulfurization scrubber, and a chemical supply tank of a two-stage wet desulfurization apparatus using liquid fertilizer and chemicals according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In order to explain the preferred embodiments of the present invention, the thicknesses of the lines and the sizes of the components shown in the attached drawings may be exaggerated or omitted for clarity and convenience of description, Terms to be given are terms defined in consideration of the functions of the present invention, which may vary depending on the intention or custom of the user, the operator.

In the biogas plant facility for anaerobic digestion of organic wastes such as livestock manure, ammonia in liquid (liquid fertilizer) is absorbed into water (NH ₃ + H ₂ O → NH ₄ OH), and the biogas plant facility (NH ₄ OH) stored in the liquid storage tank of the liquid storage tank is used as the process water to induce the reactions as shown in (a) and (b) below to reduce the amount of chemicals required to perform the economical wet desulfurization process to be.

H ₂ S + NH ₄ OH -> NH ₄ HS + H ₂ O ------- (a)

CO ₂ + 2 NH ₄ OH → (NH ₄ ) ₂ CO ₃ + H ₂ O ----- (b)

In a biogas plant facility that treats 100 ton / day of livestock manure in general, it produces 93 tons or more of manure per day and 7 tons of manure (including pollutants) per day. Of these, 10 tons or less per day can be used for desulfurization It is known.

In particular, the liquid storage tanks generally have a storage period of 9,000 to 15,000 tons in consideration of the non-fertilization period and have a stabilization period of 3 to 5 months, so that sufficient amount of liquid can be secured as a raw material for desulfurization.

For example, if the biogas production amount is 250 Nm 3 / hr and the concentration of hydrogen sulfide (H ₂ S) is 2,500 ppm or more, the amount of hydrogen sulfide generated corresponds to 860 g / hr (21 kg / day).

In general, anaerobic digestion is accomplished by decomposing ammonia hydrogen sulphide (NH ₄ HS), which is a byproduct of the reaction, to oxygen (O ₂ ) in the air by performing aeration to remove odor and stabilize it. NH ₄ ) ₂ SO ₄ , ammonium sulfate) fertilizer.

At this time, it is known that the sulfur component contained in the organic liquid fertilizer plays a role in increasing the taste and aroma inherent to the crops. In particular, crops such as watermelons are sometimes fertilized with fertilizer to increase sugar content.

The present invention is to provide a wet desulfurization apparatus and a desulfurization method using liquid fertilizer in consideration of the fact that a liquid plant can be sufficiently secured for desulfurization in a plant equipped with a biogas plant facility for treating livestock manure as described above.

As shown in FIG. 2, the wet desulfurization apparatus using a liquid fertilizer for treating hydrogen sulfide (H ₂ S) in a biogas generated from the biogas plant 600 according to the present invention includes a first stage desulfurization scrubber 100, a two-stage desulfurization scrubber 200, first and second liquid storage tanks 300 and 400, a chemical supply tank 500, a controller 700, and the like.

Here, the first-stage desulfurization scrubber 100 and the second-stage desulfurization scrubber 200 inject process-reactive water (for example, aqueous sodium hydroxide solution) used in the conventional wet chemical desulfurization apparatus shown in FIG. 1 into a spray nozzle And has the same or similar structure as a conventional desulfurization scrubber capable of removing sulfur components through chemical reaction.

2 to 5, the first stage desulfurization scrubber 100 includes a first stage scrubber body 110 modularized into a vertical tower structure and a second stage scrubber body 110 disposed in communication with the lower portion of the first stage scrubber body 110 And a second sub-reservoir (120).

A first injection nozzle unit 130 capable of injecting process reactant (liquid in the case of the present invention) is provided on the upper side of the first stage scrubber body 110, and the first injection nozzle unit 130 A first packing medium layer 140 filled with a plurality of pallets for widening the contact area of the biogas with the process reaction water (i.e., liquid) is formed on the lower side, The storage space S1 is formed so that the process reaction water (that is, liquid) that has undergone the process reaction down the layer 140 falls and can be introduced into the first lower storage tank 120. [

The first lower reservoir 120 receives and supplies process reaction water (i.e., liquid) to the second lower reservoir 220, which will be described later, according to a preferred embodiment of the present invention. 222 through the process reaction water transfer pipe 127 so that the process reaction water can be naturally supplied from the second lower storage tank 220.

Of course, the process reaction water (i.e., liquid) fed to the first bottom storage tank 120 may be supplied from the first liquid storage tank 300, which will be described later, without passing through the second bottom storage tank 220, It is of course possible to connect the first liquid storage tank 300 to the first liquid storage tank 300 through a bypass pipe (not shown) so as to be directly supplied with the liquid storage tank.

As shown in FIGS. 2 and 3, the first lower reservoir 120 is provided with a temperature sensor T for sensing the temperature of the process water, and a water level sensor (L), and has a vent hole (V) capable of venting in accordance with a change in air pressure inside the first lower reservoir (120).

The bottom of the first bottom storage tank 120 is provided with a drain outlet 126 which can be drained if necessary and the process reaction water that has undergone the process reaction on one side of the first bottom storage tank 120 And a process reaction water outlet 122 through which the liquid is discharged to the second liquid storage tank 400 through the liquid discharge pipe 410.

The first injection nozzle unit 130 receives the process reaction water from the first lower reservoir 120 through the first injection pipe 124 and the first injection pipe 124 injects the process reaction water, Stage scrubber body 110 connected to the first process reaction water outlet 123 provided at the lower end of the storage tank 120 and connected to the first injection nozzle unit 130 disposed on the upper side of the first-stage scrubber body 110.

Of course, a first injection pump 125 (not shown) capable of pumping process reactive water (i.e., liquid) in the first lower reservoir 120 and injecting the same through the first injection nozzle unit 130 is provided on the first injection pipe 124 .

A first gas inlet 111 through which the biogas can be introduced is provided on the first stage scrubber body 110 located immediately below the first packing media layer 140, And a first gas discharge port 112 through which a desulfurized biogas is discharged.

The first gas inlet 111 is an inlet passage through which the biogas produced in the biogas plant 600 flows through the gas inlet pipe 610. The first gas outlet 112 is desulfurized, Is a discharge passage through which the completed biogas escapes.

The biogas flowing into the first gas inlet 111 is supplied through the concentration analyzer installed on the gas inlet pipe 610 in a state in which the concentration of hydrogen sulfide contained in the biogas is analyzed and sensed.

The biogas introduced into the first gas inlet 111 reacts with the process reaction water (i.e., liquid) injected from the first injection nozzle unit 130 while rising through the first packing media layer 140, And the desulfurized biogas is discharged from the first-stage desulfurization scrubber 100 through the first gas discharge port 112.

At this time, the first gas outlet 112 is connected to the second gas inlet 211 of the second-stage desulfurization scrubber 200, which will be described later, through the gas pipe 150, The biogas discharged through the first gas discharge port 112 flows into the second gas inlet 211 to perform the desulfurization reaction inside the second-stage desulfurization scrubber 200 again.

The two-stage desulfurization scrubber 200 includes a two-stage scrubber body 210 modularized into a vertical tower structure and disposed in communication with the lower portion of the two-stage scrubber body 210, similarly to the first stage desulfurization scrubber 100 And a second sub-reservoir (220).

A second injection nozzle unit 230 capable of spraying liquid fertilizer, which is a process reaction water, is provided on the upper side of the two-stage scrubber body 210. Below the second spray nozzle unit 230, The first packed media layer 240 is filled with a plurality of pallets for widening the contact area of the second packed media layer 240. Process reaction water that has undergone process reaction under the second packed media layer 240 So that the storage space S2 can be formed in the second lower storage tank 220. [

The second lower reservoir 220 is a region for receiving and supplying process reaction water (i.e., liquid), and may be connected to the first process reactor feeding inlet 121 of the first lower reservoir 120 according to the preferred embodiment of the present invention ) Through the process reaction water transfer pipe 127 so as to naturally supply the process reaction water to the first lower storage tank 120.

Of course, the process reactant (i.e., liquid) supplied to the second lower reservoir 120 is bypassed through a bypass pipeline (not shown) so that the liquid responding to the process liquid may be directly supplied from the first liquid reservoir tank 300 The first liquid storage tank 300 may be connected to the first liquid storage tank 300 through piping.

As shown in FIGS. 2 and 3, the second lower reservoir 220 is provided with a temperature sensor T for sensing the temperature of the process reaction water and a water level sensor (L), and has a vent hole (V) capable of venting in accordance with a change in air pressure inside the second lower reservoir (220).

The bottom of the second bottom storage tank 120 is provided with a drain outlet 226 that can be drained if necessary and the process reaction water that has undergone the process reaction on one side of the second bottom storage tank 220, (In the case of the present invention, liquid) through the process reaction water transfer pipe 127 to the first lower booster tank 120.

The second injection nozzle unit 230 receives the process reaction water from the second bottom storage tank 220 and discharges the reaction water from the second bottom storage tank 220. A second process reaction water outlet 223 provided at the lower end of the second bottom storage tank 220, Stage scrubber body 210 is connected to the second injection nozzle unit 230 disposed inside the upper portion of the second-stage scrubber body 210. The second injection nozzle unit 230 is connected to the second injection nozzle unit 230,

Of course, the second injection pipe 224 may include a second injection pump 225 (not shown) capable of pumping process reaction water (i.e., liquid) in the second lower reservoir 220 and injecting the same through the second injection nozzle unit 230 .

A second gas inlet 211 through which the biogas can be introduced is provided on the two-stage scrubber body 210 located immediately below the second packing media layer 240, and the second injection nozzle 220 A second gas outlet 212 through which the biogas having a desulfurization degree lower than the reference value can be discharged is provided above the first gas outlet 212 and a biogas can be sent to the second gas outlet 212 as a consumer or a separate storage tank A gas discharge pipe 250 is connected.

The concentration analyzer 251 is provided on the gas discharge pipe 250 for sampling and analyzing the concentration of hydrogen sulfide (or sulfur) contained in the biogas. The concentration analyzer 251 is included in the biogas discharged to the gas discharge pipe 250 The concentration of hydrogen sulfide can be sampled for analysis and detection.

In this case, a demister 260 capable of filtering droplets contained in the biogas during the discharge of the biogas to the gas discharge pipe 250 is provided between the second gas discharge port 212 and the second discharge nozzle 230 , Denister) are preferably provided.

On the path of the gas piping 150 connecting the first gas outlet 112 of the first-stage desulfurization scrubber 100 and the second gas inlet 211 of the second-stage desulfurization scrubber 200, a first gas outlet When the desulfurization concentration of the biogas that has passed through the bypass pipe (211) reaches the set reference value (for example, 100 ppm of hydrogen sulfide can be set as a reference value) or a bypass gas pipe 160 are connected.

The bypass gas pipe 160 is connected to the gas discharge pipe 250 connected to the second gas discharge port 212 of the second-stage gas desulfurization scrubber 200 to be described later, so that the biogas gas desulfurized to a set desulfurization reference value is not shown Or to a separate storage tank.

A concentration analyzer 170 is provided on the gas pipe 150 to analyze and detect the desulfurization concentration by sampling a part of the biogas discharged from the first gas discharge port 112.

Therefore, in the concentration analyzer 170, the desulfurization state is analyzed and detected by sampling the biogas discharged from the first gas outlet 112 after the desulfurization reaction is performed in the first-stage desulfurization scrubber 100.

As a result, if it is determined that the desulfurization concentration detected by the concentration analyzer 170 is equal to a preset reference value (for example, 100 ppm of hydrogen sulfide can be set as a reference value) and it is determined that the desulfurization is performed below the reference value, The gas is sent to the gas pipe 160 and the biogas is sent to the second gas inlet 211 of the second-stage desulfurization scrubber 200 when the detected concentration of hydrogen sulfide in the biogas is higher than the reference value, ) So that the desulfurization reaction occurs again.

At this time, a first on-off valve 150a is connected between the gas pipe 150 and the second gas inlet 211, a second on-off valve 160a is connected between the gas pipe 150 and the bypass gas pipe 160, Off valve 250a is provided between the path gas pipe 160 and the gas discharge pipe 250 so that the first, second and third opening / closing valves 250a and 250b are opened and closed in accordance with the flow direction of the biogas detected and controlled by the controller 700, 150a, 160a, 250a are selectively controlled to open and close.

The first liquid storage tank 300 and the liquid storage pipe 320 are connected to each other through the second liquid storage tank 300 and the liquid storage tank 300 in the second process reservoir tank 220 of the second reservoir tank 220, (I.e., liquid fertilizer) within the reactor (i.e., the reactor).

At this time, not only a liquid supply pump 310 is provided on the liquid supply pipe 320, but also a filter unit 330 for filtering foreign substances included in the process water supplied through the liquid supply pipe 320 Lt; / RTI >

According to the present invention, the desulfurization process is performed using a solution containing ammonium hydroxide (NH ₄ OH) in the first stage desulfurization scrubber 100 and the second stage desulfurization scrubber 200 as described above However, when desulfurization at a desired level can not be achieved with only the liquid containing ammonium hydroxide (NH ₄ OH), sodium hydroxide (NaOH) or an aqueous solution of ferrous chloride (FeCl ₂ ), which is a chemical agent used in a conventional wet chemical desulfurization system As shown in FIG.

2, 4, and 5, the second reactant nozzle unit 230 is operated by the second reactant gas (liquid) in the second lower reservoir 220 in the second-stage flue gas scrubber 200, The chemical storage tank 500 is connected to the second injection pipe 224 through the chemical liquid supply pipe 520 so that sodium hydroxide (NaOH) or ferric chloride (FeCl ₂ ) aqueous solution can be supplied onto the second injection pipe 224 have.

The drug reservoir 500 includes a sodium hydroxide (NaOH) and ferrous chloride (FeCl ₂₎ and a tank for containing an aqueous solution of sodium hydroxide (NaOH) or ferrous chloride contained in the drug reservoir 500 (FeCl ₂₎ aqueous solution And is sent into the second injection pipe 224 through the chemical liquid supply pump 510 installed on the chemical liquid supply pipe 520.

In accordance with the present invention, pumped liquids such as biogas and liquid flows in the first-stage desulfurization scrubber 100, the second-stage desulfurization scrubber 200, the first and second liquid storage tanks 300 and 400, the chemical storage tank 500, The overall operation control of the desulfurization device such as the analysis and detection control of the concentration analyzer, the temperature detection, the water level detection, and the like is performed through the separately provided control unit 700 as well as the conventional control such as the opening and closing of various valves.

On the other hand, an unillustrated reference numeral 270 is an auxiliary injection pump 270, and 271 is an auxiliary injection pipe 271).

That is, the auxiliary injection pump 270 is a pump that can be used as an auxiliary when one of the first injection pump 125 and the second injection pump 225 fails, and the auxiliary injection pipe 271 is an auxiliary injection pump, The first injection pipe 124 and the second injection pipe 224 are connected to each other so that the process water can be sent to the first injection pipe 124 and the second injection pipe 224.

Reference numerals 128 and 228 denote inert gas inlets 128 and 228 capable of injecting an inert gas necessary for maintaining the first stage desulfurization scrubber 100 and the second stage desulfurization scrubber 200, Reference numeral 229 denotes inert gas discharge ports 129 and 229 capable of discharging the incombustible gas in the first stage desulfurization scrubber 100 and the second stage desulfurization scrubber 200, respectively.

The desulfurization process of the two-stage wet desulfurization apparatus according to the present invention having the above-described structure will be briefly described below.

Here, in the two-stage wet desulfurization system according to the present invention, the flow of the biogas and the flow of the liquid that is the reaction water of the process are mutually shifted and supplied, so that the flow of the liquid and the flow of the biogas will be separately described.

First, the biogas produced in the biogas plant 600 is subjected to a preparation process for desulfurization using the liquid fertilizer.

That is, in the preliminary preparation step, the liquid ratio used as the process reaction water in the first lower reservoir 120 of the first-stage desulfurization scrubber 100 and the second lower reservoir 220 of the second-stage desulfurization scrubber 200 is adjusted to a predetermined level .

That is, the process of filling the liquid into the first and second lower reservoirs 120 and 220 may include supplying the liquid stored in the first liquid storage tank 300 to the liquid supply pipe 320 in accordance with the operation of the liquid supply pump 310 Stage desulfurization scrubber 200 in a state in which foreign matter is filtered by the filter unit 330 during the process of being transferred through the process reaction water transfer pipe 127, To the first sub-reservoir 120 of the first-stage desulfurization scrubber 100, thereby completing the preparation work for performing the desulfurization step.

When bypass piping (not shown) capable of directly supplying process reaction water is installed between the first liquid storage tank 300 and the first lower storage tank 120 of the first-stage desulfurization scrubber 100 as described above It is of course possible to directly send the liquid in the first liquid storage tank 300 through the bypass piping (not shown) to the first lower storage tank 120 without going through the second lower storage tank 220.

When the liquid feed is completed in the first and second lower reservoirs 120 and 220 as a preliminary preparation step for performing the desulfurization process as described above, the biogas produced in the biogas plant 600 is supplied through the gas inlet pipe 610 Stage desulfurization scrubber 100 to perform a desulfurization process.

That is, the biogas produced in the biogas plant 600 flows into the first gas inlet 111 of the first-stage desulfurization scrubber 100 through the gas inlet pipe 610.

At this time, the biogas introduced into the first gas inlet 111 is a biogas produced through an anaerobic digestion process and is contained in the biogas analyzed and detected through a concentration analyzer installed on the gas inlet pipe 610 The concentration of hydrogen sulfide (H ₂ S) is known to be at least about 2500 ppm.

When the biogas flows into the first-stage desulfurization scrubber 100 through the first gas inlet 111, the biogas naturally rises and passes through the first packing media layer 140.

As the biogas is introduced and raised, the operation liquid, which is the process reaction water accommodated in the first lower reservoir 120 of the first-stage desulfurization scrubber 100, is supplied to the first injection nozzle unit 130 To be sprayed.

The liquid contained in the first lower reservoir 120 is supplied to the first injection nozzle 130 inside the upper portion of the first stage scrubber body 110 through the first injection pipe 124 by the first injection pump 125, To be sprayed.

The droplet jetted through the first jet nozzle unit 130 goes down through the first packing media layer 140.

The biogas and the liquid are contacted with each other while passing through the first packed media layer 140 through the opposite flow process as described above, so that the desulfurization reaction occurs.

That is, the hydrogen sulfide (H ₂ S) and the carbon dioxide (CO ₂ ) contained in the biogas are chemically reacted with the ammonium hydroxide (NH ₄ OH) contained in the liquid so that the desulfurization reaction occurs through the following reaction formula.

H ₂ S + NH ₄ OH -> NH ₄ HS + H ₂ O ------- (a)

CO ₂ + 2 NH ₄ OH → (NH ₄ ) ₂ CO ₃ + H ₂ O ----- (b)

After the chemical reaction has occurred, the liquid is collected in the first bottom storage tank 120 through the first packing media layer 140, and then the reacted liquid is sent to the second liquid storage tank 400.

That is, the process reaction water (i.e., liquid), which has undergone the process reaction through the process reaction water outlet 122 provided at one side of the first bottom storage tank 120 and the liquid discharge pipe 410 connected to the pipeline, And is sent to the storage tank 400.

At this time, if the ammonium bicarbonate ((NH ₄ ) ₂ CO ₃ ) form is present in the solution by the reaction of (b), the alkaline degree is kept high, thereby buffering the pH to prevent the decrease of pH.

As described above, the liquid waste sent to the second liquid storage tank 400 is subjected to the following chemical reaction during the aeration process by injecting air to generate ammonium sulfate (NH ₄ ) ₂ SO ₄ ) .

NH ₄ HS + 3O ₂ + H ₂ O ---> NH ₄ + HS + HO + H ₂ O + O ₂

---> SO ₂ + H ₂ O → H ₂ SO ₃ + H ₂ O

---> 2H ₂ SO ₃ + O ₂ → 2H ₂ SO ₄ + H ₂ O

---> 2NH ₃ + H ₂ SO ₄ + H ₂ O → (NH ₄ ) ₂ SO ₄ + H ₂ O

In other words, it is known that the sulfur component contained in the organic liquid fertilizer plays a role in increasing the taste and flavor inherent to the crop. In particular, in the crops such as watermelon, the sulfur (ammonium sulfate, (NH ₄ ) ₂ SO ₄₎ It is to secure a fertilizer component such as hydrogen sulphide, ammonium ₂ SO ₄₎ (NH ₄ HS), ammonium sulfate (ammonium sulfate, (NH ₄ through) contained in the liquid manure in the desulfurization process of randomly situation with the case of fertilization the fertilizer liquid ratio It is possible to expect an effect of enhancing the functionality.

After the desulfurization reaction in the first stage desulfurization scrubber 100, the biogas discharged to the first gas discharge port 112 is sampled by the concentration analyzer 170 provided on the gas pipeline 150 to analyze the desulfurization state .

As a result, it is judged that the desulfurization is performed below the reference value by comparing the desulfurization concentration (that is, the concentration of the hydrogen sulfide) analyzed by the concentration analyzer 170 with a preset reference value (for example, 100 ppm of hydrogen sulfide can be set as a reference value) The biogas is sent to the bypass gas pipe 160 and then sent to the customer and a separate storage tank through the gas discharge pipe 250.

In this case, since desulfurization can be performed at a desired level by simply performing a desulfurization process using a solution containing ammonium hydroxide (NH ₄ OH) in the first-stage desulfurization scrubber 100, sodium hydroxide ) Or a ferrous chloride (FeCl ₂ ) aqueous solution.

When it is analyzed that the detected value of hydrogen sulfide (H ₂ S) in the biogas is higher than the reference value, it is judged that the desulfurization in the biogas can not reach the desired level only by the first stage desulfurization scrubber 100 according to the present invention In this case, the biogas having passed through the first-stage desulfurization scrubber 100 is sent to the second gas inlet 211 of the second-stage desulfurization scrubber 200 through the gas pipe 150, and the second-stage desulfurization scrubber 200 ) So that the desulfurization reaction occurs again.

That is, according to the present invention, the biogas containing a large amount of hydrogen sulfide (H ₂ S) through the anaerobic digestion process in the biogas plant 600 is introduced into the first-stage desulfurization scrubber 100, (H ₂ S) reacts with ammonium hydroxide (NH ₄ OH) in the liquid so that the concentration drops.

The biogas in which the concentration of hydrogen sulfide (H ₂ S) is first reduced is supplied from the first gas outlet 112 located above the first-stage desulfurization scrubber 100 to the second gas located below the second- Stage desulfurization scrubber 200 through the gas piping 150 connected to the inlet 211 and flows through the second packed media layer 240 as it ascends, (H ₂ S) is removed by reacting with ammonium hydroxide (NH ₄ OH) in the liquid ratio injected to the nozzle unit 230.

When the biogas having passed through the first-stage desulfurization scrubber 100 flows into the second-stage desulfurization scrubber 200 as described above, as in the first-stage desulfurization scrubber 100, The second spraying nozzle unit 230 and the second spraying nozzle unit 230 through the second spraying pipe 224 by the operation of the second spraying pump 225, And then the reacted liquor is sent to the first bottom storage tank 120 through the process reaction water transfer pipe 127. In this case,

When the desulfurized reaction solution is introduced into the first bottom storage vessel 120 of the first-stage desulfurization scrubber 100 through the process reaction water transfer pipe 127 as described above, The liquid is repeatedly injected into the upper first injection nozzle unit 130 by the first injection pump 125 and sprayed so that the sprayed liquid comes into contact with the biogas in the first packing media layer 140, The reaction is completed and flows to the first sub-storage tank 120. The reacted liquid is then sent to the second liquid storage tank 400 repeatedly.

In addition, since the reacted liquid as described above is sent to the second liquid storage tank 400, a new liquid is stored in the first liquid storage tank 300 to the second lower storage tank 220 of the second-stage desulfurization scrubber 200 And continuously controlled so as to perform a continuous desulfurization process while maintaining the level of the liquid slurry in the first and second lower reservoirs 120 and 220 at a constant level.

Meanwhile, as described above, the biogas and the liquid having opposite flows flow through the first-stage desulfurization scrubber 100 and the second-stage desulfurization scrubber 200, respectively, The desulfurized biogas below the reference value is finally sent to a customer or another storage tank through a second gas outlet 212 and a gas discharge pipe 250 located above the second-stage desulfurization scrubber 200.

As described above, the biogas discharged to the gas discharge pipe 250 is finally analyzed for the concentration of the desulfurization concentration through the hydrogen sulfide concentration analyzer 251 installed in the gas discharge pipe 250.

In the first stage desulfurization scrubber 100 and the second stage desulfurization scrubber 200, only the solution containing ammonium hydroxide (NH ₄ OH) in the biogas is used as the hydrogen sulfide (H ₂ S ) Can not reach the desired level sufficiently. Therefore, in this case, it is necessary to use an aqueous solution of sodium hydroxide (NaOH) or ferrous chloride (FeCl ₂ ), which is a chemical agent used in a conventional wet chemical desulfurization apparatus, It will be done.

That is, when the concentration of hydrogen sulfide in the biogas discharged to the gas discharge pipe 250 is equal to or higher than the target concentration, sodium hydroxide (NaOH) in the chemical storage tank 500 is used as an auxiliary chemical agent for desulfurization, And is supplied into the scrubber 200.

The sodium hydroxide (NaOH) is supplied from the chemical storage tank 500 through the chemical liquid supply pump 510 and the chemical liquid supply pipe 520 into the liquid solution flowing along the second injection pipe 224 to be supplied to the second injection nozzle unit 230 As shown in FIG.

As described above, when sodium hydroxide (NaOH) is sprayed from the second injection nozzle unit 230 of the second-stage desulfurization scrubber 200 together with the liquor, the reaction process in the second-stage desulfurization scrubber 200 is performed in the same manner as described above Along with the desulfurization reaction by ammonium hydroxide (NH ₄ OH), hydrogen sulfide (H ₂ S) and carbon dioxide (CO ₂ ) contained in the biogas cause the following two reactions simultaneously.

H ₂ S + NaOH → NaHS + H ₂ O (1)

CO ₂ + ₂ NaOH - > Na ₂ CO ₃ + H ₂ O ------- (2)

The above-mentioned reaction is the same as the reaction occurring in the desulfurization scrubber in the conventional one-stage wet chemical desulfurization system, and most of the wet chemical desulfurization systems using sodium hydroxide (NaOH) And it is a method applied to most wet chemical desulfurization systems at home and abroad.

The two-stage wet desulfurization system according to the present invention is a system in which a conventional one-stage wet chemical desulfurization system is improved and developed. In the two-stage desulfurization scrubber 200, an aqueous solution of sodium carbonate (Na ₂ CO ₃ , soda) Is introduced into the first-stage desulfurization scrubber 100 and then is sprayed from the first injection nozzle unit 130 on the first-stage desulfurization scrubber 100 to react with hydrogen sulfide (H ₂ S) contained in the biogas as follows.

H ₂ S + Na ₂ CO _{3 -} > NaHS + NaHCO ₃ - (3)

That is, when sodium hydroxide (NaOH) is supplementarily used, when the biogas is introduced into the first-stage desulfurization scrubber 100 for desulfurization, a part of hydrogen sulfide (H ₂ S) And the final desulfurization is performed through the reactions (1) and (2) in the second stage desulfurization scrubber 200.

In the course of performing the desulfurization process by supplying a solution containing ammonium hydroxide (NH ₄ OH) to the second stage desulfurization scrubber 200 according to the present invention, an aqueous solution of sodium hydroxide (NaOH) is supplied to the second stage desulfurization scrubber 200 The desulfurization reaction with ammonium hydroxide (NH ₄ OH) and the desulfurization reaction with sodium hydroxide (NaOH) occur at the same time in the second stage desulfurization scrubber 200, and sodium carbonate (Na ₂ CO _3, sodium), an aqueous solution is produced, and thus the resulting sodium carbonate (Na ₂ CO _3, sodium), an aqueous solution is sent to the first-stage desulfurization scrubber 100 via a number of transport pipe 127 step reaction first stage in accordance with the load desulfurization In the scrubber 100, the desulfurization operation is performed only with sodium carbonate (Na ₂ CO ₃ ) generated in the second-stage desulfurization scrubber 200, so that the required amount of aqueous sodium hydroxide (NaOH) solution can be significantly reduced All.

As described above, the desulfurization process by the slurry in the first-stage desulfurization scrubber 100 and the second-stage desulfurization scrubber 200 is carried out in such a manner that ammonium hydrogen (NH ₄ OH) contained in the slurry reacts with biogas to generate hydrogen sulfide (H ₂ S) process, and the step of adjuvant used in the chemicals in the two stage gas desulfurization scrubber 200 to remove utilizes one as auxiliary liquid drug desulfurization process, ammonium hydroxide (NH ₄ OH) of manure utilization of sodium hydroxide (NaOH) (H ₂ S) is removed and the concentration of hydrogen sulfide (H ₂ S) is higher than the target value, the amount of sodium hydroxide (NaOH) Which can reduce the consumption of sodium hydroxide (NaOH).

Meanwhile, the two-stage wet desulfurization system according to the present invention can be applied as it is as a conventional wet chemical desulfurization system in a situation in which it is difficult to supply liquid.

For this purpose, as shown in FIG. 2, a water supply unit 800 capable of supplying water into the first and second lower reservoirs 120 and 220 is connected to the first and second reservoirs 120 and 220, It goes without saying that sodium (NaOH) or ferrous chloride (FeCl ₂ ) aqueous solution can be used as the process reaction water.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the invention as defined by the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

100: First stage desulfurization scrubber 110: First stage scrubber body
111: first gas inlet 112: first gas outlet
120: first bottom reservoir 121: first process reaction feeding inlet
122: First process Reaction water outlet 123: First injection pipe end connection
124: first injection pipe 125: first injection pump
126: first drain outlet 127: process reaction water transfer piping
130: first jet nozzle part 140: first packing medium layer
150: gas piping 160: bypass gas piping
170, 251: Concentration analyzer 200: Second-stage desulfurization scrubber
210: two-stage scrubber body 211: second gas inlet
212: second gas outlet 220: second bottom reservoir
221: Second process Reaction feeding inlet 222: Second process Reaction water outlet
223: Second injection pipe connection port 224: Second injection pipe
225: second injection pump 226: second drain outlet
230: second jetting nozzle part 240: second packing medium layer
250: gas discharge pipe 300: first liquid storage tank
310: Liquid supply pump 320: Liquid supply piping
330: filter unit 400: second liquid storage tank
410: Liquid discharging pipe 500: Medicine storage tank
510: chemical liquid supply pump 520: chemical liquid supply line
600: Biogas plant 610: Gas inlet pipe
700: control unit 800: water supply unit

Claims (7)

The biogas produced in the biogas plant 600 for anaerobic digestion of the organic waste composed of livestock manure is introduced through the first gas inlet 111 and the first gas inlet 111 located below the first gas inlet 111, The solution containing ammonium hydroxide (NH ₄ OH) contained in the storage tank 120 is pumped upward through the first injection pump 125 on the first injection pipe 124 and injected by the first injection nozzle unit 130 And the liquid is contacted with the biogas in the first packing media layer 140 located below the first injection nozzle unit 130, so that the desulfurization reaction occurs, and the biogas that has been reacted is supplied to the first gas A first stage desulfurization scrubber 100 configured to be discharged through a discharge port 112 and to discharge the reacted liquid to the second liquid storage tank 400 after being collected in the first lower storage tank 120, The first gas exhaust of the first-stage desulfurization scrubber (100) The biogas discharged through the first gas inlet 112 flows through the second gas inlet 211 through the gas piping 150 and the hydrogas absorbed in the second bottom reservoir 220 located below the second gas inlet 211 A solution containing ammonium (NH ₄ OH) is pumped upward through the second injection pump 225 on the second injection pipe 224 and is sprayed by the second injection nozzle unit 230, The desulfurization reaction occurs in contact with the biogas in the second packing media layer 240 located below the injection nozzle unit 230 and the biogas is reacted through the second gas outlet 212 on the upper side, Stage desulfurization scrubber 20 having a structure capable of being discharged to the first bottom storage vessel 250 and discharged to the first bottom storage vessel 120 through the process reaction water transfer pipe 127 after being collected in the second bottom storage vessel 220, Stage desulfurization scrubber 200, and the second sub-reservoir 220 of the second- To be sent to filter liquid ratio feed pump 310 and the filter unit hydroxide associated with the second lower reservoir 220 by a manure supply pipe 320 equipped with a 330 ammonium is (NH ₄ OH) to store the manure containing the A concentration analyzer 170 for analyzing the concentration of the desulfurization gas in the biogas gas is provided on the gas pipeline 150 and a desulfurization concentration analyzer 170 for analyzing the concentration of the desulfurization gas, And a bypass gas pipe (160) capable of opening and closing the biogas to the gas discharge pipe (250) is provided on the gas pipe (150).
delete The method according to claim 1,
A sodium hydroxide or a ferrous chloride solution which is connected to the second injection pipe 224 by a chemical liquid supply pipe 520 having a chemical liquid supply pump 510 so as to supply process reaction water as a chemical agent into the second injection pipe 224, And a chemical storage tank (300) in which any one of the chemical reagents is stored. The wet desulfurization apparatus using the liquid slurry in the biogas plant.
In the wet desulfurization scrubber, the process reaction water is injected from the upper part through the injection nozzle part, the biogas generated from the biogas plant is introduced from the lower part, and the process reaction water and the biogas are brought into contact with each other in the packing media layer, The method for desulfurizing a wet desulfurization apparatus according to claim 1, wherein the reaction gas is a reaction gas.
As the process reaction water channel, a solution containing ammonium hydroxide (NH ₄ OH) is used,
The desulfurization scrubber is disposed in series with a two-stage desulfurization scrubber so as to constitute the first-stage desulfurization scrubber 100 and the second-stage desulfurization scrubber 200, and the liquid reaction, which is the process reaction water stored in the first liquid storage tank 300, And then flows into the lower second reservoir 220 of the second stage desulfurization scrubber 200. The liquid ratio thus introduced flows through the second injection pump 225 and the second injection pipe 224 to the upper second injection nozzle 230 and then discharged to the second lower reservoir 220 through the second packing media layer 240 and the liquid dropped to the second lower reservoir 220 flows through the process reaction water transfer pipe 127, Stage desulfurization scrubber 200 through the first injection pump 125 on the first injection pipe 124 to the upper portion of the first lower reservoir 120 through the first injection pump 125, And is collected in the first lower reservoir 120 through the first packing media layer 140 as it is injected into the first injection nozzle unit 130 Well, the reacted liquid is sent to the second liquid storage tank 400,
As the biogas is introduced into the first gas inlet 111 under the first-stage desulfurization scrubber 100, the hydrogen sulfide (H ₂ S) in the biogas passes through the first packing media layer 140, NH ₄ OH) and the concentration of the hydrogen sulfide is first reduced. The biogas is discharged from the first gas outlet 112 above the first-stage desulfurization scrubber 100 to the second Stage desulfurization scrubber 200 through the gas piping 150 connected to the gas inlet 211 and reacts with ammonium hydroxide (NH ₄ OH) in the liquid mixture flowing through the second packing medium layer 240 in the second- Wherein the biogas is discharged through a gas discharge pipe (250) provided at an upper part of the second-stage desulfurization scrubber (200), and the desulfurization method of the wet desulfurization apparatus using the liquid slurry in the biogas plant.
delete 5. The method of claim 4,
The desulfurization concentration of the biogas in the first-stage desulfurization scrubber 100 is analyzed through the concentration analyzer 170 provided on the gas pipeline 150, and the desulfurization concentration of the biogas is set to a set reference value The biogas is discharged to the gas discharge pipe 250 through the bypass gas pipe 160 connecting the gas pipe 150 and the gas discharge pipe 250 without sending the biogas into the second stage desulfurization scrubber 200 A desulfurization method of a wet desulfurization apparatus using a liquid in a biogas plant.
The method according to claim 4 or 6,
The desulfurization concentration in the biogas discharged to the gas discharge pipe 250 is analyzed and when the desulfurization concentration is higher than the target concentration, any one of sodium hydroxide (NaOH) and ferrous chloride (FeCl ₂ ) aqueous solution in the chemical storage tank 500 Is supplied into the second injection pipe 224 of the second-stage desulfurization scrubber 200 and is sprayed through the second injection nozzle unit 230 together with the liquid ratio flowing along the second injection pipe 224 to contact with the biogas, Wherein the desulfurizing step is carried out in a desulfurization apparatus using a liquid slurry in a biogas plant.

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