KR102368058B1 - Biogas purification system and purification method using the same - Google Patents

Abstract

The present invention relates to a biogas purification system without pretreatment and a purification method using the same. The present invention absorbs and separates impurities other than methane (CH_4) in biogas using an absorbent in an absorption unit without performing a pretreatment process of first separating impurities that cause corrosion from biogas, thereby preventing corrosion from occurring in the absorption unit and capturing high-purity methane.

Description

A biogas purification system that does not require pretreatment and a purification method using the same

The present invention relates to a biogas purification system that does not require pretreatment and a purification method using the same, and more particularly, using an absorbent in the absorption part in which corrosion does not occur even without performing a pretreatment of first separating corrosion-causing impurities. By absorbing and separating impurities other than methane (CH ₄ ) in biogas, it relates to a biogas purification system for collecting high-purity methane and a purification method using the same.

Biogas is a gas mixture produced when organic substances such as food waste, landfill waste, livestock manure, sewage sludge, and leachate are decomposed through anaerobic digestion.

The gas mixture mainly contains methane (CH ₄ ), carbon dioxide (CO ₂ ) as impurities, a small amount of hydrogen sulfide (H ₂ S), moisture, ammonia and other trace components.

Methane contained in biogas can be used as an energy source, but there is a limit to the utilization of biogas because impurities other than methane are included.

Accordingly, purification technology for removing impurities in biogas to maximize the utility of biogas is classified into adsorption method, absorption method, and membrane separation method.

Among biogas purification technologies, it relates to an absorption method, and the invention related thereto is disclosed in Korean Patent Publication No. 10-1322224 (hereinafter, Document 1).

Document 1 The invention relates to a method and system for deoxidizing a gas mixture in which an acid gas is absorbed by contacting a gas mixture with an absorbent in an absorption unit, and the gas mixture is converted into a purified gas mixture.

In the invention of Document 1, an amine solution is used as an absorbent to absorb the acid gas, but there is a problem in that hydrogen sulfide in the acid gas causes corrosion in the absorption unit.

As an invention for solving the problem of corrosion caused by hydrogen sulfide as in the invention of Document 1 above, Patent Publication No. 10-2011-0117809 (hereinafter, Document 2), Patent Publication No. 10-1534802 (hereinafter, Document 3) ) and Patent Publication No. 10-2021-0097905 (hereinafter, Document 3) discloses the inventions related thereto.

Document 2 The invention relates to a high-purity biogas purification system and a biogas purification method in which carbon dioxide is removed using an adsorbent after pretreatment of moisture, hydrogen sulfide and siloxane contained in biogas.

Document 3 Invention relates to a biogas purification system including an amine absorption unit in which carbon dioxide is separated using an amine after hydrogen sulfide contained in biogas is pretreated and methane is recovered.

In the inventions of Documents 2 and 3, in order to prevent the absorption tower from being corroded by hydrogen sulfide contained in the gas, the hydrogen sulfide is first removed in the desulfurization device, but the following problems occur.

For example, when the desulfurization device is a dry type as in the inventions of Documents 2 and 3, it is difficult to operate due to insufficient data such as capacity, removal efficiency according to filler, replacement cycle, etc., and it is inconvenient to periodically replace the desulfurization agent (iron oxide). .

For example, when the desulfurization apparatus is a wet method as in the invention of Document 2, the circulation pipe is frequently clogged due to caustic soda condensation in winter, or when sulfur components are excessively introduced, corrosion occurs in the apparatus located at the rear end of the desulfurization apparatus.

Document 4 The invention relates to a system and process for adsorbing and separating carbon dioxide from a mixed gas by using an absorbent after pretreatment of moisture and sulfur dioxide (SO ₂ ) contained in the mixed gas.

The invention of Document 4 uses a biodesulfurization method using sulfated microorganisms. The biodesulfurization method requires high operating technology because the sulfuric acid microorganisms have different desulfurization efficiency depending on conditions such as temperature, pH, and oxygen concentration. is needed

<Background art literature>

(Document 1) Registered Patent Publication No. 10-1322224

(Document 2) Patent Publication No. 10-2011-0117809

(Document 3) Registered Patent Publication No. 10-1534802

(Document 4) Patent Publication No. 10-2021-0097905

An object of the present invention is to solve the problems of the background art, and to provide a biogas purification system that does not require pre-treatment and a purification method using the same.

In particular, an object of the present invention is that corrosion is not caused by impurities contained in biogas even if pretreatment of biogas is not performed.

In addition, an object of the present invention is to provide high-purity methane by absorbing and separating impurities other than methane in biogas by using an absorbent in an absorber to collect only methane.

Furthermore, an object of the present invention is to prevent air pollution because biogas from which methane is separated is not released into the atmosphere as it is post-processed and separated and collected into carbon dioxide and hydrogen sulfide.

In order to achieve the above object, the biogas purification system of the present invention includes an absorber in which impurities other than methane in the biogas are absorbed by reacting the introduced biogas with an absorbent; a separation unit in which the absorbent into which the impurities are absorbed is introduced, the impurities and the absorbent are separated by the supplied heat source to regenerate the absorbent; a supply unit disposed between the absorption unit and the separation unit, wherein the absorbent regenerated in the separation unit is transferred to the absorption unit, and the absorbent in which impurities generated in the absorption unit are absorbed is transferred to the separation unit; a heat source supply unit to which a heat source is supplied to the separation unit; and a post-processing unit in which the impurities separated in the separation unit are introduced and separated into carbon oxides and sulfur compounds; A biogas purification system, characterized in that it is included.

The absorbent in the present invention is characterized in that water or an amine-based (amine) compound aqueous solution is used.

In the present invention, the impurities are characterized in that any one or more of carbon oxides, sulfur compounds, and moisture is included.

In the present invention, the heat source is characterized in that any one of hot water, warm oil, and steam.

In the present invention, the post-processing unit is characterized in that a filter is used.

The biogas purification system of the present invention is characterized in that it further includes a nitrification unit for increasing the purity of the methane separated in the absorption unit.

In the present invention, the nitridation unit includes: a filter unit into which the methane separated in the absorption unit is introduced, and impurities other than methane are adsorbed; a compression unit in which methane discharged from the filter unit is introduced, and the methane is compressed for fuel conversion; and a drying unit in which moisture is removed from the methane compressed in the compression unit; characterized in that it is included.

In the present invention, the purification method using the biogas purification system includes the steps of: (a) reacting biogas with an absorbent in an absorber to absorb impurities other than methane; (b) separating the absorbent into which the impurities produced in step (a) have been absorbed by reacting with a heat source in a separation unit to separate the impurities and the absorbent; and (c) separating the impurities separated in step (b) into carbon oxides and sulfur compounds through a post-treatment unit; characterized in that it is included.

In addition, the purification method using the biogas purification system of the present invention is characterized in that it further includes the step of (d) converting the methane separated in the step (a) into a fuel by passing through the nitrification unit.

The biogas purification system and the purification method using the same, which do not require pre-treatment according to the present invention, can operate stably even if the pre-treatment of biogas is not performed, and there is an effect that corrosion does not occur due to impurities contained in biogas.

The present invention absorbs and separates impurities other than methane in biogas using an absorbent in the absorber, but has the advantage of providing high-purity methane with a methane loss of less than 0.1%.

In addition, in the present invention, as the biogas from which methane is separated is post-processed and separated and collected into carbon dioxide and hydrogen sulfide, there is an effect of reducing greenhouse gas and preventing air pollution.

Furthermore, the present invention has the effect that the separated and captured carbon dioxide and hydrogen sulfide can be recycled in various ways.

1 is a conceptual diagram for explaining a biogas purification system according to the present invention.
FIG. 2 is a flowchart illustrating a purification method using the biogas purification system shown in FIG. 1 .
3 is a conceptual diagram for explaining a biogas purification system according to another embodiment of the present invention.
4 is a flowchart illustrating a purification method using the biogas purification system shown in FIG. 3 .
5 is a conceptual diagram for explaining a biogas purification system according to another embodiment of the present invention.
6 is a flowchart illustrating a purification method using the biogas purification system shown in FIG. 5 .
7 is a conceptual diagram for explaining a biogas purification system according to another embodiment of the present invention.
<Explanation of code>
1: Biogas 2: Methane
3: carbon oxide 4: sulfur compound
10: absorption part
20: separation unit
25: cooling unit
30: supply unit 31: heat exchange unit
40: heat source supply unit
50: post-processing unit
60: nitrification unit 61: filter unit 62: compression unit
63: drying unit
70: recovery unit
80: cooling unit
90: processing unit

Hereinafter, the present invention will be described in detail through examples.

Objects, features, and advantages of the present invention will be readily understood through the following examples.

The present invention is not limited to the embodiments disclosed herein, and may be embodied in other forms. The embodiments disclosed herein are provided so that the spirit of the present invention can be sufficiently conveyed to those of ordinary skill in the technical field to which the present invention belongs, and all transformations included in the technical spirit and scope of the present invention , should be understood to include equivalents or substitutes.

Therefore, the present invention should not be limited by the following embodiments, and it should be understood that all transformations included in the technical spirit and scope of the present invention are included. That is, those of ordinary skill in the art to which the present invention pertains can variously modify or modify the present invention by adding, changing, deleting, or adding components within the scope that does not depart from the spirit of the present invention described in the claims. It will be possible to change, and this will also be said to be included within the scope of the present invention.

Since the present invention is capable of various modifications and various embodiments, specific embodiments are illustrated in the drawings and described in detail. In the drawings, the size of elements or the relative sizes between elements may be exaggerated for a clear understanding of the present invention. In addition, the shape of the element shown in the drawings may be slightly changed due to variations in the manufacturing process or the like.

Therefore, the embodiments disclosed herein should not be limited to the shapes shown in the drawings unless otherwise noted, but should be understood to include some degree of deformation.

On the other hand, various embodiments of the present invention may be combined with any other embodiments unless clearly indicated to the contrary. Any feature indicated as particularly preferred or advantageous may be combined with any other feature and features indicated as preferred or advantageous. That is, the various aspects, features, embodiments or implementations of the present invention may be used alone or in various combinations.

It should be understood that the terminology used herein is for the purpose of describing specific embodiments and is not intended to be limited by the claims, and all technical and scientific terms used in this specification are those of ordinary skill unless otherwise noted. has the same meaning as is commonly understood by a person with The singular expression includes the plural expression unless the context clearly dictates otherwise.

In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

<Example 1>

1 , the biogas purification system may include an absorption unit 10 , a separation unit 20 , a supply unit 30 , a heat source supply unit 40 , and a post-processing unit 50 .

In the absorption unit 10, the biogas 1 is introduced, and the absorbent is dispersed inside and reacts the introduced biogas 1 with the absorbent to absorb impurities except for the methane 2 in the biogas 1 can

Here, the biogas (1) is a gas mixture produced by anaerobic digestion of any one or more organic substances such as food waste, landfill waste, livestock manure, sewage sludge, or leachate, methane (CH ₄ ), carbon oxides, sulfur compounds, Moisture and other trace ingredients may be included.

The carbon oxide is a compound made of only carbon and oxygen, and may include any one or more of carbon monoxide (CO), carbon dioxide (CO ₂ ), nitrous oxide (C ₃ O ₂ ), or mellitic anhydride (C ₁₂ O ₉ ).

The carbon oxide contained in the biogas 1 may include carbon monoxide or carbon dioxide, but is not particularly limited thereto because the type of carbon oxide produced may vary depending on the anaerobic digested organic material.

The sulfur compound is a compound containing sulfur, and may include any one or more of hydrogen sulfide (H ₂ S), carbon disulfide (CS ₂ ), or carbonyl sulfide (COS).

The sulfur compound contained in the biogas 1 may include hydrogen sulfide, but is not particularly limited thereto because the type of sulfur compound produced may vary depending on the organic material being anaerobically digested.

Of course, the biogas purification system can be purified by applying gas generated and discharged from factories, power plants, etc. in addition to the biogas 1 described above.

In order to prevent the inflow of the biogas 1 and the absorbent from flowing out, the absorber 10 may be formed to have a space for the biogas 1 and the absorbent to stay, but to have a closed front.

In this case, the absorber 10 may have a biogas inlet pipe connected to the lower side of the absorber 10 in order to introduce the biogas 1 generated from the outside.

An anaerobic digestion device or a biogas collection device may be connected to one end of the biogas inlet pipe, and the other end may be connected to the lower side of the absorption unit 10 . In this case, a transfer pump or blower may be further included in the biogas inlet pipe to transfer the biogas from the anaerobic digestion device or the biogas collection device to the absorption unit 10 .

In addition, the absorber 10 may have a methane discharge pipe connected to the upper end of the absorber 10 in order to discharge the methane 2 separated from the biogas 1 as the biogas 1 and the absorbent react. .

The methane discharge pipe is connected to the upper end of the absorption unit 10 at one end, and is connected to the collecting unit at the other end so that methane 2 is not released into the atmosphere, thereby preventing air pollution and enabling recycling.

The absorber 10 may include a spray nozzle capable of spraying the absorbent on the upper inner surface in order to react the introduced biogas 1 with the absorbent. At this time, the injection nozzle may be connected to the absorbent transport pipe connected to the upper side of the absorption unit 10 .

The absorbent may be supplied from the outside once or periodically, or the absorbent regenerated in the separation unit 20 to be described later through the absorbent transfer pipe may be re-supplied.

In addition, the injection nozzle may be rotated in the absorption unit 10 in order to promote the reaction between the biogas 1 and the absorbent to increase the absorption rate of impurities in the biogas 1 .

Further, the absorber 10 is included in the absorber 10 in order to improve the absorption efficiency of carbon oxide and sulfur compounds in the biogas 1 by the sprayed absorbent, and the porosity and effective area under the injection nozzle are large. Although lightweight, a filler having strength, corrosion resistance, and heat resistance may be further included.

The filling may be formed in any one or more shapes of tripaks, balls, saddles, hi rex, and pall rings, but is not particularly limited thereto.

In addition, the filling material may be formed of a material having corrosion resistance to sulfur compounds in order to prevent corrosion of the filling material as the sulfur compound causing corrosion in the biogas 1 is absorbed and separated by the absorbent. Preferably, the filler may be formed of any one or more materials of steel, stainless steel, or polypropylene (PP, polypropylene) having corrosion resistance to sulfur compounds.

Furthermore, the filler may be replaceable in order to prevent impurities other than methane (2) in the biogas (1) from lowering the separation efficiency of the absorbent due to clogging.

In addition, in order to minimize the drift phenomenon in which the absorbent flows in only one direction in the absorbent part 10 including the filler, it is preferable that the diameter of the absorbent part 10 / the diameter of the filler satisfy the range of 8 to 10.

Further, the filling may be regularly or irregularly filled in the absorbent section 10, and preferably, the filling is regularly filled in the absorbent section 10 so that the pressure loss is small and a larger amount of the absorbent can flow. .

The absorption part 10 may further include a support member in order to prevent the filling from falling and clogging the discharge pipe included at the bottom of the absorption part 10 when the filling material described above is filled therein.

The support member is included in the absorption part 10, and is disposed higher than the biogas inlet pipe and lower than the injection nozzle, so that the filler can be mounted on the upper surface of the support member.

In addition, the support member may have a plurality of holes formed therein so that the absorbent in which the impurities generated in the absorbent unit 10 are absorbed may fall in the lower direction of the absorbent unit 10 .

At this time, in order to prevent the filler from falling out into the plurality of holes, it is preferable that the diameter of the hole is smaller than the diameter of the filler.

A discharge pipe may be included at the lower end of the absorption unit 10 so that the absorbent in which impurities are absorbed may be discharged.

At this time, the discharge pipe is connected to the lower end of the absorption unit 10 at one end and passes through the supply unit 30 , but at the other end is connected to the upper side of the separation unit 20 , so that the absorbent in which impurities are absorbed flows into the separation unit 20 . can be

The absorbent absorbs only impurities in the incoming biogas (1), but water or an amine compound aqueous solution that does not absorb methane (2) may be used, and preferably, any one or more of carbon oxides, sulfur compounds, or moisture An aqueous solution of an amine-based compound that absorbs impurities but does not absorb methane (2) may be used.

For example, when water is used as the absorbent, in order to absorb any one or more impurities among carbon oxides, sulfur compounds, and moisture in the biogas 1 flowing into the absorber 10, water at 0° C. or higher is fed into the absorber 10. It may be supplied, but it is not limited thereto because the temperature of water may vary depending on the concentration of the carbon oxide or sulfur compound.

In this case, the water may be supplied to the absorber 10 at 25° C. or higher in order to absorb carbon dioxide among the carbon oxides.

In this case, in order to absorb the hydrogen sulfide among the sulfur compounds, water at 45° C. or higher may be supplied to the absorption unit 10 .

Accordingly, as for the water, in order to simultaneously absorb carbon dioxide and hydrogen sulfide in the biogas 1 , water at 25 to 45° C. is preferably supplied to the absorption unit 10 .

For example, when an amine-based compound aqueous solution is used as the absorbent, at least one or more hydroxyl groups ( -OH) and an amine group (-NH ₂ ) having an alkanol amine (alkanol amine) may be used.

Preferably, the alkanol amine absorbs carbon dioxide and hydrogen sulfide among the impurities at the same time to purify the biogas, and monoethanolamine (MEA, Mono Ethanol Amine), diethanolamine (DEA, Any one of Di Ethanol Amine), triethanolamine (TEA, Tri Ethanol Amine) or methyl diethanolamine (MDEA, Methyl Di Ethanol Amine) may be used.

The monoethanolamine has the advantage that it can be reused by heating when impurities are absorbed.

Compared with the monoethanolamine, the diethanolamine has relatively less corrosion of the absorption part 10, and has the advantage that it can be reused using activated carbon.

The triethanolamine and methyl diethanolamine have a fast reaction with hydrogen sulfide, react relatively slowly with carbon dioxide, so that hydrogen sulfide and carbon dioxide can be selectively separated, there is no corrosion of the absorption unit 10, and there is an advantage that can be reused by heating.

Therefore, the present invention uses any one selected from monoethanolamine, triethanolamine, or methyl diethanolamine that can be reused by heating among alkanol amines as the absorbent, so that carbon dioxide in the biogas 1 is reduced due to a high separation effect. There is an effect that separation is possible to 50ppm or less.

In addition, since the alkanol amine has a characteristic in which hydrogen sulfide is absorbed, there is an effect that hydrogen sulfide pretreatment is not required.

In particular, the present invention has the advantage that hydrogen sulfide is highly separated from the biogas (1) and the residual amount is 1 ppm or less, but the loss of separated methane is less than 0.1%, so that high nitrogen methane production is possible.

Accordingly, the present invention has the effect of purifying more than 99% of carbon dioxide and hydrogen sulfide contained in the biogas (1).

The alkanol amine is to be injected in the lower direction of the absorber 10 by the injection nozzle included in the absorber 10 as the biogas 1 introduced into the absorber 10 moves from the bottom to the top. can

At this time, the alkanol amine reacts with impurities other than the methane of the biogas 1 to generate an alkanol amine in which the impurities are absorbed.

Here, the methane may be discharged to the outside through a methane discharge pipe included at the upper end of the absorption unit 10, and the alkanol amine in which the impurities are absorbed is supplied to the supply unit ( 30) and may be introduced into the separation unit 20 .

In the separation unit 20, the absorbent in which the impurities generated in the absorption unit 10 are absorbed is introduced, and as the absorbent in which the impurities are absorbed is separated by the heat source supplied to the inside, the regenerated absorbent can be reused. can

In this case, the separation unit 20 may be installed adjacent to the absorption unit 10 .

As the heat source, any one of hot water, warm oil, or steam of 20 to 160° C. may be introduced into the separation unit 20 through the heat source supply unit 40 installed adjacent to the separation unit 20 .

For example, when hot water or steam is used as a heat source, it may be supplied to the separation unit 20 at a temperature of 20 to 145°C.

For example, when warm oil is used as a heat source, it may be supplied to the separation unit 20 at a temperature of 20 to 155°C.

In addition, in order to prevent contamination of hot water, warm oil, or steam used in the heat source supply unit 40, but to recover the used heat source and reuse it, a pipe connected to the heat source supply unit 40 is connected to the separator 20 lower The heat source may be indirectly provided by being introduced into the inner surface.

At this time, the heat source supply unit 40 is used in the separation unit 20 and the recovered heat source is 45 to 85 ° C. As the recovered heat source is reheated and reused in the heat source supply unit 40, the total energy consumption can be lowered. There is an advantage.

The separation unit 20 may be formed in a shape in which the front side is closed in order to prevent the outflow of the absorbent and the absorbent separated by the heat source from the absorbent into which the introduced impurities are absorbed.

At this time, in the separation unit 20 , a pipe connected to the heat source supply unit 40 is introduced into the other inner surface of the lower side of the separation unit 20 so that the heat source supplied by the heat source supply unit 40 is provided to the separation unit 20 . can be

In addition, in the separation unit 20 , the other end of the discharge pipe described above may be connected to the upper side surface of the separation unit 20 in order to introduce the absorbent in which the impurities generated in the absorption unit 10 are absorbed.

Here, the discharge pipe may include a transfer pump so that the absorbent in which the impurities have been absorbed can be transferred from the absorption unit 10 to the separation unit 20 direction.

The exhaust pipe and the pipe connected to the heat source supply unit 40 may be disposed so as not to cross each other.

In the separation unit 20 , an absorbent transport pipe may be connected to the lower end of the separation unit 20 in order to discharge the absorbent from which impurities are separated by the heat source supplied by the heat source supply unit 40 , that is, the regenerated absorbent.

The absorbent transport pipe is connected to one side of the upper side of the absorbent unit 10 at one end and passes through the supply unit 30 , but is connected to the lower end of the separation unit 20 at the other end so that the regenerated absorbent can be introduced into the absorbent unit 10 . .

In this case, the absorbent transport pipe may be disposed so that pipes connected to the heat source supply unit 40 do not cross each other.

The absorbent conveying pipe may include a conveying pump so that the regenerated absorbent generated in the separation unit 20 can be conveyed from the separation unit 20 to the absorption unit 10 .

Accordingly, the absorbent introduced into the absorbent unit 10 has the advantage that only a small installation space is required as the regenerated absorbent generated in the separation unit 20 can be used.

In addition, the separation unit 20 has an impurity discharge pipe formed at an upper end thereof, so that impurities from which the absorbent is separated by the heat source supplied by the heat source supply unit 40 may be discharged.

In this case, the upper end of the separation unit 20 may be connected to one end of the impurity discharge pipe, and the other end may be connected to the side of the post-processing unit 50 .

In order to transport the impurities in a gaseous state to the post-processing unit 50 along the impurity discharge pipe, a blower may be further included in the impurity discharge pipe.

As shown in FIG. 1, the supply unit 30 is disposed between the absorption unit 10 and the separation unit 20, and reuse and recycling of the absorbent used to absorb and separate impurities other than methane from biogas. There are possible advantages.

Here, in the supply unit 30, the regenerated absorbent produced in the separation unit 20 is transferred to the absorbent unit 10 along the absorbent transfer pipe, and the absorbent in which impurities generated in the absorber 10 are absorbed is transferred along the discharge pipe. It may be transferred to the separation unit 20 .

In this case, heat exchange may occur by disposing the absorbent transport pipe passing through the supply unit 30 and the discharge pipe to cross each other.

When an amine-based compound aqueous solution is used among the absorbents used in the absorber 10 as an example, the absorption rate of impurities of the biogas 1 with respect to the amine-based compound aqueous solution is closely related to the temperature.

For example, if the temperature of the aqueous solution of the amine-based compound is low, a large amount of impurities may be absorbed into the aqueous solution of the amine-based compound.

For example, if the temperature of the aqueous solution of the amine-based compound in which the impurities are absorbed is high, degassing may be performed well in the aqueous solution of the amine-based compound in which the impurities are absorbed.

Accordingly, it is advantageous for the absorption unit 10 to have a low temperature, and, conversely, for the separation unit 20 to maintain a high temperature.

Therefore, the regenerated absorbent separated and discharged from the separation unit 20 moves toward the absorption unit 10 along the absorbent transfer pipe at a high temperature, so that a large amount of impurities are absorbed into the amine-based compound aqueous solution. The temperature needs to be lowered before the absorbed absorbent reaches the absorbent section (10).

Similarly, the absorbent in which the impurities discharged from the absorption unit 10 are absorbed moves toward the separation unit 20 along the discharge pipe at a low temperature, so that in the amine-based compound aqueous solution in which the impurities are absorbed, degassing of impurities is well performed. In order to do this, it is necessary to increase the temperature before the aqueous solution of the amine-based compound into which the impurities are absorbed reaches the separation unit 20 .

That is, in the present invention, the absorbent transport pipe passing through the supply unit 30 and the discharge pipe may be disposed to cross each other, and a heat exchanger may be disposed at the crossing point.

In this case, the heat exchanger disposed at the crossing point absorbs the heat of the regenerated absorbent moving toward the absorbent unit 10 along the absorbent transfer pipe, so that the cooled regenerated absorbent may be introduced into the absorber 10 .

In addition, the heat exchanger disposed at the intersecting point transfers the absorbed heat to the discharge pipe, and the amine-based compound aqueous solution in which impurities moving toward the separation unit 20 are absorbed flows into the separation unit 20 in a heated state. can be

Accordingly, in the present invention, energy consumption for additional heating or cooling by the heat exchanger included in the supply unit 30 is prevented, and the absorption or degassing efficiency of the amine-based compound aqueous solution is not reduced.

In the post-processing unit 50, impurities (gas phase) separated and discharged from the separation unit 20 may be introduced, and may pass through a filter included therein to be separated into carbon oxides and sulfur compounds.

In order to prevent the introduced impurities from flowing out, the post-processing unit 50 may be formed in a shape in which a space is formed for the impurities to stay and the front is closed.

In this case, the post-processing unit 50 may have an impurity inflow pipe connected to the lower side of the post-processing unit 50 in order to introduce the introduced impurities.

In this case, the impurity inlet pipe may further include a blower for transferring the impurities to the post-processing unit 50 .

In addition, the post-processing unit 50 may include a spray nozzle through which the liquid fertilizer can be sprayed on the upper inner surface. At this time, the injection nozzle to which the liquid fertilizer is sprayed may be connected to the liquid fertilizer supply pipe included in the upper side of the post-processing unit 50 .

The injection nozzle to which the liquid fertilizer is sprayed may be rotatable in the post-processing unit 50 in order to promote the supply of moisture and nutrients to the microorganisms included in the filter.

Here, in the post-processing unit 50, the liquid fertilizer sprayed by the spray nozzle flows down along the filling described at the rear end, and moisture and nutrients are supplied to the microorganisms, so that the growth of the microorganisms is not reduced.

In this case, the filter described above in the absorption unit 10 may be used, and preferably, the filler described below in which microorganisms are immobilized may be used.

Here, in order to prevent the filling from falling and clogging the air supply pipe and the sulfur compound discharge pipe included at the bottom of the post-processing unit 50, a support member may be further included.

The support member is included in the post-processing unit 50, is disposed higher than the impurity inlet pipe, and is disposed lower than the injection nozzle through which the liquid fertilizer is sprayed, so that the filler in which the microorganisms are immobilized can be mounted on the upper surface of the support member.

In this case, in the support member, a plurality of holes may be formed so that sulfate and sulfur generated by the filling in which the microorganisms included in the post-processing unit 50 are immobilized fall in the lower direction of the post-processing unit 50 .

In this case, the plurality of holes may be formed so that the diameter of the hole is smaller than the diameter of the filler in order to prevent the filler from falling out.

The air supply pipe included at the bottom of the post-processing unit 50 may be supplied with oxygen for biologically removing hydrogen sulfide.

At this time, the air supply pipe and the sulfur compound discharge pipe included in the lower end of the post-processing unit 50 may be disposed so as not to interfere with each other.

In addition, a carbon oxide discharge pipe may be included at the upper end of the post-processing unit 50 .

As the microorganism, bacteria that oxidize hydrogen sulfide to sulfate ions and elemental sulfur may be used.

In this case, the filter in which the microorganisms are immobilized on the filling may be referred to as a bio filter as a biofilm is formed.

The impurities introduced into the biofilter may be oxidatively decomposed by the metabolism of the microorganism, and finally discharged in the form of carbon dioxide and metabolites of the microorganism.

The bacteria may include sulfated bacteria in order to separate the impurities introduced into the post-processing unit 50 into hydrogen sulfide and carbon dioxide.

The sulfated bacteria may oxidatively decompose using only hydrogen sulfide contained in the impurities as an energy source, thereby producing carbon dioxide and sulfate and sulfur (S) as metabolites.

Accordingly, in the post-processing unit 50 including the biofilter, carbon dioxide may be discharged as carbon oxide 3 through a carbon oxide discharge pipe, and sulfate and sulfur may be discharged as sulfur compound 4 through a sulfur compound discharge pipe.

That is, the post-processing unit 50 separates and discharges the impurities into carbon dioxide, sulfate, and sulfur, or collects and recycles the carbon dioxide, sulfate, and sulfur, respectively, thereby reducing greenhouse gas emissions and preventing air pollution. .

The following is a description of a purification method using the biogas purification system shown in FIG. 1 .

The purification method may be sequentially performed as shown in FIG. 2 .

First, (a) the biogas 1 and the absorbent react in the absorber 10 to absorb impurities except for methane may be performed.

In step (a), the biogas 1 is introduced into the absorber 10 along the biogas inlet pipe of the absorber 10 as described above, and the absorbent or the separation unit 20 by the absorbent transfer pipe The generated regenerated absorbent may be sprayed into the absorber 10 by the spray nozzle.

At this time, the biogas 1 reacts with the absorbent injected by the injection nozzle, and impurities other than methane are absorbed by the absorbent, and the absorbent in which the impurities are absorbed is separated along the discharge pipe formed at the bottom of the absorption unit 10 . may be transferred to the unit 20 .

Next, (b) the absorbent in which the impurity generated in step (a) has been absorbed is reacted with a heat source in the separation unit 20 to separate the impurities and the absorbent into the absorbent.

In step (b), the absorbent in which the impurity transferred by the discharge pipe in step (a) has been absorbed is introduced into the separation unit 20, and the absorbent in which the impurities are absorbed by the heat source supply unit 40 is heated. Impurities and absorbents can be separated from each other.

In this case, the absorbent separated by heating is a regenerated absorbent, and is transferred to the absorbent unit 10 along the absorbent transfer pipe and reused, thereby reducing maintenance costs.

In addition, in step (b), methane is not included in the absorbent in which the impurities introduced into the separation unit 20 are absorbed by step (a) performed above, or when the biogas (1) is purified to a content of less than 0.1% In the biogas (1), the methane loss is less than 0.1%, which can indicate a high methane separation effect.

Here, impurities separated by heating may be transferred to the post-processing unit 50 in a gaseous phase along an impurity discharge pipe formed at the top of the separation unit 20 .

Next, (c) the impurity separated in step (b) passes through the post-processing unit 50 to separate into carbon oxides and sulfur compounds may be performed.

In step (c), the impurities transported by the impurity discharge pipe in step (b) may be introduced into the post-processing unit 50, and may pass through the biofilter to be separated into carbon dioxide, sulfate, and sulfur, respectively.

In this case, the carbon dioxide separated through the step (c) may be discharged through the carbon oxide discharge pipe or may be collected and recycled.

At this time, the sulfate and sulfur separated through the step (c) may be discharged through the sulfur compound discharge pipe, or may be collected and combusted or recycled.

The biogas purification system described above is a pressureless process, and electricity is consumed at 0.1 kWh/m ³ gas, thereby reducing maintenance costs, but has the advantage of being user-friendly and safe to operate.

In addition, the biogas purification system can be modularized, so there is an advantage that flexible installation is possible.

<Example 2>

The absorption part 10 of the first embodiment may be made of a material that prevents corrosion.

Here, the biogas purification system and the purification method may be configured in the same manner as in Embodiment 1 described above except for the material of the absorption unit 10 .

The absorber 10 may be made of a stainless steel material in order to prevent the inside of the absorber 10 from being corroded by hydrogen sulfide among the sulfur compounds contained in the introduced biogas 1 .

The stainless steel may be composed of 16 to 18% by weight of chromium (Cr), 10 to 14% by weight of nickel (Ni), 2 to 3% by weight of molybdenum (Mo), the remainder of iron (Fe), and other unavoidable impurities.

The other unavoidable impurities may include an additional 2 wt% or less of any one or more of carbon (C), silicon (Si), manganese (Mn), phosphorus (P), and sulfur (S).

Preferably, carbon 0.08 wt% or less, silicon 1 wt% or less, manganese 2 wt% or less, phosphorus 0.045 wt% or less, and sulfur 0.03 wt% or less may be included.

The chromium is a very thin film of chromium oxide (Cr ₂ O ₃ ) is formed on the surface of the iron, and the film acts as a passivity layer to block oxygen penetrating into the iron. can

The nickel may be included in order to maintain an austenite structure even at room temperature.

The molybdenum may be included in order to increase corrosion resistance and acid resistance to prevent chloride stress corrosion cracking (CISCC, Chloride-Induced Stress Corrosion Cracking) and pitting corrosion.

Accordingly, the stainless steel of the present invention is a Fe-Cr-Ni-Mo-based stainless steel, and has excellent corrosion resistance and acid resistance.

In particular, since the stainless steel of the present invention contains molybdenum, there is an effect of reducing an acid such as hydrogen sulfide flowing into the absorption unit 10 to prevent corrosion.

Accordingly, in order to prevent corrosion by hydrogen sulfide among impurities absorbed in the absorbent in the separation unit 20 into which the absorbent is absorbed, the separation unit 20 and the absorption unit are prevented from being corroded. (10) It goes without saying that the discharge pipe included at the bottom may also be made of the same material as the absorption part 10 .

In addition, in order to prevent the post-processing unit 50 from being corroded by sulfate and sulfur among the impurities, the post-processing unit 50 and the upper end of the separating unit 20 , into which impurities separated and discharged from the separating unit 20 are introduced. Of course, the impurity discharge pipe included in the absorbing unit 10 may be made of the same material.

<Example 3>

The cooling unit 25 may be further included in the biogas purification system of the first embodiment or the second embodiment.

The biogas purification system may be configured in the same manner as in Embodiment 1 or Embodiment 2 described above except for the cooling unit 25 .

Referring to FIG. 3 , the cooling unit 25 may be disposed between the separation unit 20 and the post-processing unit 50 described above.

At this time, the cooling unit 25 is connected to the impurity discharge pipe included in the upper end of the separation unit 20, so that impurities separated and discharged from the separation unit 20 are introduced, and only water is removed from the impurities. may be included.

Accordingly, the impurities separated and discharged from the separation unit 20 pass through the cooling unit 25, and the impurities from which the moisture has been removed are introduced into the post-processing unit 50, and as described above, the impurities from which the moisture has been removed are carbon dioxide and It can be discharged separately as sulphate and sulfur.

The following is a description of the purification method using the biogas purification system shown in FIG. 4, and steps (a), (b) and (c') may be sequentially performed.

Steps (a) and (b) may be performed in the same manner as in Example 1 described above.

After the step (b), a step (c') of the impurities separated in the step (b) passing through the cooling unit 25 and the post-processing unit 50 to be separated into carbon oxides and sulfur compounds may be performed.

In step (c'), the impurities transported by the impurity discharge pipe in step (b) are introduced into the cooling unit 25 , and moisture is removed through heat exchange of the cooling pipe included in the cooling unit 25 . impurities may be formed.

At this time, the impurities from which moisture has been removed may be introduced into the post-processing unit 50 and passed through the biofilter described above to be separated into carbon dioxide, sulfate, and sulfur, respectively.

In this case, the carbon dioxide separated through the step (c') may be discharged through the carbon oxide discharge pipe or may be collected and recycled.

In this case, the sulfate and sulfur separated through the step (c') may be discharged through the sulfur compound discharge pipe, or may be collected and combusted or recycled.

<Example 4>

The nitridation unit 60 may be further included in any one of the biogas purification systems selected from Examples 1 to 3.

The biogas purification system may be configured in the same manner as in any one selected from Examples 1 to 3 described above, except for the nitrification unit 60 .

Referring to FIG. 5 , the nitridation unit 60 removes any one or more of low-concentration carbon dioxide, hydrogen sulfide, or volatile organic compounds contained in the methane 2 discharged from the absorption unit 10 to increase the purity of methane. For this purpose, a filter unit 61 , a compression unit 62 , and a drying unit 63 may be included.

5, the filter unit 61, the compression unit 62, and the drying unit 63 may be sequentially disposed in the methane discharge pipe described above.

In the filter unit 61 , the methane 2 separated and discharged from the absorption unit 10 described above is introduced through the methane discharge pipe, and impurities other than the methane 2 may be adsorbed.

At this time, the methane 2 flowing into the filter unit 61 may contain any one or more of low-concentration carbon dioxide, hydrogen sulfide, and volatile organic compounds.

Accordingly, in the filter unit 61, a carbon filter may be used in order to adsorb and remove any one or more of low-concentration carbon dioxide, hydrogen sulfide, and volatile organic compounds, except for methane (2).

The carbon filter is a porous material and is included in the filter unit 61 to adsorb and remove only low-concentration carbon dioxide, hydrogen sulfide, and volatile organic compounds except for methane 2, thereby producing high-nitration methane.

In addition, the carbon filter may be replaceable in order to prevent a decrease in adsorption performance due to clogging of pores by adsorbed low-concentration carbon dioxide, hydrogen sulfide, and volatile organic compounds.

Furthermore, it goes without saying that a plurality of carbon filters may be formed in a stacked structure in the filter unit 61 .

The compression unit 62 is disposed next to the filter unit 61 so that methane discharged from the filter unit 61 is introduced, and methane of high concentration can be generated by compressing the methane for fuel conversion.

The drying unit 63 is disposed after the compression unit 62, and the high concentration methane discharged from the compression unit 62 is introduced therein, and moisture may be removed from the high concentration methane.

The high-concentration methane from which moisture has been removed through the drying unit 63 is indicated by 2' in FIG. 5, and may be separately collected and used for power generation or heating, or may be used as a substitute for transportation fuel or natural gas.

The following is a description of the purification method using the biogas purification system shown in FIG. 6, and in the purification method of Example 1 described above, (d) the methane (2) separated in the step (a) is converted into a high nitrification unit ( The step of being converted into fuel by passing through 60) may be additionally performed.

In this case, in step (d), the methane 2 separated in step (a) described above may be sequentially passed through the filter unit 61 , the compression unit 62 , and the drying unit 63 .

In step (d), the methane 2 separated in step (a) described above passes through the filter unit 61, and any of low-concentration carbon dioxide, hydrogen sulfide, or volatile organic compounds contained in the methane 2 One or more may be adsorbed off.

Thereafter, the methane that has passed through the filter unit 61 may pass through the compression unit 62 disposed next to the filter unit 61 , and the methane may be compressed to generate methane with a high concentration.

Next, the high-concentration methane that has passed through the compression unit 62 may pass through the drying unit 63 to remove moisture from the high-concentration methane.

Accordingly, the biogas purification system including the nitridation unit 60 has an advantage in that carbon dioxide, hydrogen sulfide, and volatile organic compounds do not remain in the methane separated from the absorption unit 10, so that nitridation methane can be generated.

In particular, the nitrified methane has an effect that it can be used as a fuel because the purity of the methane is increased.

<Example 5>

A gas cooling unit may be further included in the nitridation unit 60 of the fourth embodiment.

Here, the biogas purification system may be configured in the same manner as in Example 4 described above except for the gas cooling unit.

As shown in FIG. 7 , the gas cooling unit is disposed between the compression unit 62 and the drying unit 63 , and a cooling pipe may be included therein.

At this time, the high-concentration methane discharged from the compression unit 62 may pass through the gas cooling unit. Accordingly, the high-concentration methane introduced through the heat exchange of the cooling pipe included in the gas cooling unit may be cooled to generate liquefied methane.

The liquefied methane may be introduced into the drying unit 63 disposed after the gas cooling unit to remove moisture from the liquefied methane.

A gas cooling unit is further included in the nitrification unit 60 so that the filter unit 61, the compression unit 62, the gas cooling unit and the drying unit 63 are sequentially arranged to finally produce liquefied methane, so that the liquefied methane is It has the advantage of excellent transport and storage.

In the purification method using the biogas purification system further including the gas cooling unit, step (d) of Example 4 described above may be performed.

At this time, in step (d), the methane 2 separated in step (a) described above may sequentially pass through the filter unit 61 , the compression unit 62 , the gas cooling unit and the drying unit 63 . there is.

In step (d), the methane 2 separated in step (a) described above passes through the filter unit 61, and any of low-concentration carbon dioxide, hydrogen sulfide, or volatile organic compounds contained in the methane 2 One or more may be adsorbed off.

Thereafter, the methane that has passed through the filter unit 61 may pass through the compression unit 62 disposed next to the filter unit 61 , and the methane may be compressed to generate methane with a high concentration.

Next, the high-concentration methane that has passed through the compression unit 62 passes through the gas cooling unit, and the high-concentration methane introduced through heat exchange of a cooling pipe included in the gas cooling unit is cooled to generate liquefied methane.

Thereafter, the liquefied methane generated in the gas cooling unit may pass through the drying unit 63, and moisture may be removed from the liquefied methane.

<Example 6>

A gas analyzer may be further included in the nitridation unit 60 of the fifth embodiment.

Here, the biogas purification system may be configured in the same manner as in Example 5 described above except for the gas analyzer.

The gas analyzer may be disposed next to the drying unit 63 as shown in FIG. 7 .

At this time, when the liquefied methane from which moisture is removed from the drying unit 63 passes through the gas analyzer, it can be checked whether impurities remain in the liquefied methane.

For example, the gas analysis unit is performed by any one of absorption method, combustion method, titration method, gravimetric method, colorimetric method, test strip method, detection tube method, physical gas analysis method, low temperature distillation method, or gas chromatography to check whether impurities remain in liquefied methane. .

If it is confirmed through the gas analyzer that impurities remain in the liquefied methane, the impurities may be adsorbed and removed by transferring them back to the filter unit 61 .

If it is confirmed through the gas analyzer that no impurities remain in the liquefied methane, it may be separately collected and used for power generation or heating, or may be used as a substitute for transportation fuel or natural gas.

In the purification method using the biogas purification system further including the gas analyzer, step (d) of Example 5 described above may be performed.

At this time, in step (d), the methane 2 separated in step (a) described above is sequentially performed by the filter unit 61 , the compression unit 62 , the gas cooling unit, the drying unit 63 and the gas analysis unit. can be passed

In step (d), the methane 2 separated in step (a) described above passes through the filter unit 61, and any of low-concentration carbon dioxide, hydrogen sulfide, or volatile organic compounds contained in the methane 2 One or more may be adsorbed off.

Thereafter, the methane that has passed through the filter unit 61 may pass through the compression unit 62 disposed next to the filter unit 61 , and the methane may be compressed to generate methane with a high concentration.

Next, the high-concentration methane that has passed through the compression unit 62 passes through the gas cooling unit, and the high-concentration methane introduced through heat exchange of a cooling pipe included in the gas cooling unit is cooled to generate liquefied methane.

Thereafter, the liquefied methane generated in the gas cooling unit may pass through the drying unit 63, and moisture may be removed from the liquefied methane.

Next, the liquefied methane from which moisture has been removed may pass through a gas analyzer to determine whether impurities remain in the liquefied methane.

Through this, the present invention has an advantage that it can be used immediately without additional purification work because impurities in the final liquefied methane produced by passing through the nitridation unit 60 do not remain.

<Example 7>

A heat exchange unit 31 , a recovery unit 70 , a cooling unit 80 , and a processing unit 90 may be further included in any one of the biogas purification systems selected from Examples 1 to 6 above.

Here, the biogas purification system may be configured in the same manner as in each of the above-described embodiments except for the heat exchange unit 31 , the recovery unit 70 , the cooling unit 80 , and the processing unit 90 .

An arrow with an empty interior shown in FIG. 7 and a broken line indicates the flow of hard water, and an arrow that is filled inside and formed with a broken line indicates the flow of hot water.

Referring to FIG. 7 , the heat exchange unit 31 may be included in an absorbent transport pipe positioned between the absorption unit 10 and the supply unit 30 .

When the regenerated absorbent is transferred along the absorbent transfer pipe, the regenerated absorbent may sequentially pass through the supply unit 30 and the heat exchange unit 31 to be transferred to the absorber 10 .

At this time, the 45° C. hot water generated in the heat exchange unit 31 may be recovered by the recovery unit 70 .

The recovery unit 70 recovers heat generated during the operation of the biogas purification system and discharges some of the recovered heat to the outside to supply heat to facilities requiring heat, such as a digester, and some of the heat may be supplied as shown in FIG. 7 . It is possible to prevent overheating of the biogas purification system by supplying it to the cooling unit 80 .

In addition, as shown in FIG. 7 , the recovery unit 70 may recover hot water at 70° C. generated by the compression unit 62 and condensed water generated by the cooling unit 25 .

The cooling unit 80 is a cooling facility, and hot water and heat recovered through the recovery unit 70 are supplied, but some of the soft water generated by the processing unit 90 may be supplied.

Accordingly, the cooling unit 80 has the advantage that the efficiency is not lowered by maximally lowering the total heat consumption and heat loss for cooling to lower the temperature of the hot water and heat recovered by the supplied soft water.

The processing unit 90 may include a light water softening device for converting hard water flowing in from the outside into soft soft water having a low hardness.

At this time, some of the soft water generated through the processing unit 90 is supplied to the cooling unit 80 as shown in FIG. 7 , and the remaining soft water is partially supplied to the separating unit 20 through the cooling unit 25 . there is.

The soft water supplied to the separator 20 may be mixed with the regenerated absorbent, and the regenerated absorbent in an aqueous solution may be supplied to the absorber 10 .

In the biogas purification system further including the heat exchange unit 31 , the recovery unit 70 , the cooling unit 80 and the processing unit 90 , heat and hot water are recovered by the recovery unit 70 , and in the cooling unit 80 . There is an advantage that the soft water is used less.

<Example 8>

Microorganisms immobilized on the filling used in the post-processing unit 50 included in any one of the biogas purification systems selected from Examples 1 to 7 may include bacteria and fungi.

The bacteria may include the sulphating bacteria described in Example 1.

The fungus is, in order to separate the impurities introduced into the post-processing unit 50 into hydrogen sulfide and carbon dioxide, Acidomyces acidophilus or Aspergillus fumigatus Any one or more molds may be included.

If the bacteria are used alone in the filling, they are sensitive to changes in pH, and thus, when the pH changes rapidly, the activity of the bacteria may be reduced.

For example, when the fungus is used alone in the filling, the initial acclimatization period may take a long time because the metabolic rate is relatively lower than that of the bacteria.

Accordingly, a complex microbial community in which the bacteria and mold are mixed may be used in the filter in order to improve the problem that occurs when the filter inoculated with bacteria or mold alone is used.

At this time, as the complex microbial community is used as a biofilter, there is an advantage in that the efficiency of removing hydrogen sulfide is improved because bacteria are attached to the surface of the mycelia of the mold.

Accordingly, in the post-processing unit 50 including the bio-filter in which the complex microbial community is formed, carbon dioxide is discharged as carbon oxide 3 through a carbon oxide discharge pipe, and sulfate and sulfur as a sulfur compound 4 are discharged through a sulfur compound discharge pipe. can be

<Example 9>

A carbon dioxide collecting unit may be further included in the carbon oxide exhaust pipe included in any one of the biogas purification systems selected from Examples 1 to 8.

The biogas purification system except for the carbon dioxide collecting unit may be formed in the same manner as in each embodiment.

Here, the carbon dioxide collecting unit is connected to the other end of the carbon oxide discharge pipe described above, and collects the carbon dioxide separated through the post-processing unit 50 to prevent carbon dioxide from being emitted into the atmosphere, thereby reducing greenhouse gases.

The carbon dioxide captured by the carbon dioxide collecting unit can be used for various purposes, thereby reducing environmental pollution caused by carbon dioxide emission.

As an example, the captured carbon dioxide may be used by manufacturing dry ice.

In the dry ice manufacturing method, the collected carbon dioxide is purified by dissolving impurities in water, and after removing moisture, cooling and pressure are applied to the purified carbon dioxide to convert it into liquid carbon dioxide.

In this case, when additional pressure is applied to the liquid carbon dioxide, dry ice, which is carbon dioxide in a solid form, may be generated.

As another example, the captured carbon dioxide can be prepared as formic acid and used in medicines, preservatives, and the like.

As another application example, after refining the captured carbon dioxide, it may be injected into a plastic house. Carbon dioxide injected into the greenhouse can be used for photosynthetic activity of crops, thereby increasing crop yield.

As another example, the captured carbon dioxide can be used for culturing microalgae.

The microalgae can produce oxygen and organic matter by using the captured carbon dioxide through photosynthesis.

By separately collecting oxygen generated by photosynthesis of microalgae and injecting it into the biofilter of the post-processing unit 50 described above, the activity of sulfated bacteria can be improved.

The organic material contains a triglyceride (TAG, triacylglyceride) in which fatty acids and glycerol (glycerol) are combined.

Here, when triglyceride is reacted with methanol, it can be separated into glycerol and fatty acid methyl ester (FAME).

In this case, the separated fatty acid methyl ester may be referred to as bio-diesel.

The biodiesel has the advantage of being able to prevent air pollution by reducing the generation of fine dust due to the use of diesel by replacing or mixing diesel with petroleum-based diesel.

<Example 10>

A collection unit may be further included in the sulfur compound discharge pipe included in any one of the biogas purification systems selected from Examples 1 to 9.

The biogas purification system except for the collecting unit may be formed in the same manner as in each embodiment.

Here, the collecting unit is connected to the other end of the sulfur compound discharge pipe described above and collects any one or more of hydrogen sulfide and sulfur separated through the post-processing unit 50 to prevent odor from being emitted into the atmosphere, thereby preventing air pollution.

The hydrogen sulfide and sulfur collected in the collection unit are combusted or used for various purposes, thereby reducing environmental pollution by enabling recycling.

The captured hydrogen sulfide and sulfur may be burned after being transferred to a combustor.

The combustor is a regenerative combustor, and by burning the captured hydrogen sulfide and sulfur at a high temperature of 800° C. or higher, odors are not emitted into the atmosphere.

The present invention is a biogas purification system that does not require pretreatment and a purification method using the same. Even when impurities except methane (CH ₄ ) are absorbed and separated from the biogas by using an absorbent in the absorber, corrosion does not occur, so high-purity methane It is an industrially available invention that can capture

Claims (10)

an absorption unit in which impurities other than methane in the biogas are absorbed by reacting the introduced biogas with an absorbent;
a separation unit in which the absorbent into which the impurities are absorbed is introduced, the impurities and the absorbent are separated by the supplied heat source to regenerate the absorbent;
a supply unit disposed between the absorption unit and the separation unit, wherein the absorbent regenerated in the separation unit is transferred to the absorption unit, and the absorbent in which impurities generated in the absorption unit are absorbed is transferred to the separation unit;
a heat source supply unit to which a heat source is supplied to the separation unit; and
The impurities separated in the separation unit are introduced, and the impurities pass through a filter in which the microorganisms are immobilized in the packing material, and the impurities are oxidized and decomposed by the metabolism of the microorganisms. ; It is a pressureless process that includes
As the absorbent, an aqueous solution of an amine compound is used,
Impurities include any one or more of carbon oxides, sulfur compounds, or moisture,
The heat source includes any one of hot water, warm oil, or steam,
In order to prevent the absorber from being corroded by the sulfur compounds contained in the incoming biogas, the absorber is made of a stainless steel material and does not require pretreatment, the biogas purification system. The method according to claim 1,
In order to increase the absorption rate of impurities in the biogas by promoting the reaction between the biogas and the absorbent in the absorber, any one or more of a rotatable injection nozzle or a replaceable filler is further included in the absorber. system. The method according to claim 1,
The post-processing unit, biogas purification system, characterized in that the liquid fertilizer is sprayed in order to supply moisture and nutrients to the microorganisms. The method according to claim 1,
In the biogas purification system, impurities separated and discharged from the separation unit are introduced, and a cooling unit is further included between the separation unit and the post-processing unit in order to remove moisture from the impurities. The method according to claim 1,
The microorganism is a sulphating bacterium, Acidomyces acidophilus (Acidomyces acidophilus) or Aspergillus fumigatus (Aspergillus fumigatus) characterized in that it includes any one or more, biogas purification system. The method according to claim 1,
The biogas purification system further includes a nitrification unit to increase the purity of methane separated in the absorption unit,
The nitrification unit includes a filter unit into which methane separated from the absorption unit is introduced, and impurities other than methane are adsorbed;
a compression unit in which methane discharged from the filter unit is introduced, and the methane is compressed for fuel conversion;
a drying unit in which moisture is removed from the methane compressed in the compression unit;
a gas cooling unit in which methane discharged from the compression unit is cooled to produce liquefied methane; or
a gas analyzer that checks whether impurities remain in the methane; Any one or more of which is characterized in that, the biogas purification system. The method according to claim 1,
Biogas purification system,
a heat exchange unit included between the absorption unit and the supply unit to generate hot water by heat exchange;
a recovery unit in which the hot water is recovered, the recovered heat is discharged to the outside, heat is supplied to a facility requiring heat, or is supplied to a cooling unit to prevent overheating;
a cooling unit in which hot water and heat are supplied by the recovery unit, and a part of the soft water generated in the processing unit is supplied to reduce heat consumption and loss; and
a processing unit that converts hard water introduced from the outside into soft water and is supplied to the cooling unit and the separation unit;
The biogas purification system, characterized in that it further comprises. In the purification method using the biogas purification system of any one of claims 1 to 7,
(a) the biogas and the absorbent react in the absorption unit to absorb impurities except for methane;
(b) separating the absorbent into which the impurities produced in step (a) have been absorbed by reacting with a heat source in a separation unit to separate the impurities and the absorbent; and
(c) the impurities separated in step (b) pass through a post-processing unit including a filter in which the microorganisms are immobilized in the packing material, and the impurities are oxidatively decomposed by the metabolism of the microorganisms, respectively, into carbon dioxide, sulfate and sulfur separating and collecting;
A purification method using a biogas purification system, characterized in that it is included. 9. The method of claim 8,
The purification method using the biogas purification system,
(d) The purification method using a biogas purification system, characterized in that it further comprises the step of converting the methane separated in step (a) into fuel by passing through the nitrification unit. delete

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