KR102016808B1 - Method and System for Gas purification - Google Patents

Abstract

A gas purification method is provided. The gas purification method includes a step of introducing a target gas, a first step of removing a first gas containing carbon and sulfur from the target gas, and oxygen and silicon from the target gas on which the first step is performed. A second step of removing a second gas, and a third step of removing a third gas including hydrogen and sulfur from the target gas on which the second step is performed, wherein the first to third steps are sequentially It can be performed as.

Description

Gas purification method and system {Method and System for Gas purification}

The present invention relates to a gas purification method and system, and more particularly, to a gas purification method and system in which first to third gases are sequentially removed from a target gas.

When anaerobic digestion of organic substances such as sewage sludge, food waste, livestock manure and slaughter waste is carried out with oxygen blocked, a gas called Anaerobic Digestion Gas (ADG) or Biogas is generated. Biogas is composed of 45 to 70% methane, 30 to 55% carbon dioxide, hundreds to thousands of ppm hydrogen sulfide, hundreds to thousands of ppm ammonia, moisture and siloxanes. The methane contained in biogas is designated as the representative greenhouse gas with global warming index 21. Since its own energy amount is about 5,000 kcal / ㎥, the purification and recovery of methane from biogas prevents global warming, resource recycling, The goal of securing renewable energy can be achieved.

Biogas can be used as a resource to produce city gas and automobile fuel through high-purity through direct combustion and combined heat and power (CHP), refining, and environmental and economical efficiency around biogas sources. Therefore, various applications are being developed. For example, Korean Patent Publication No. 10-2017-0050087 (Application No .: 10-2015-0151154, Applicant: Korea Institute of Industrial Technology), removes and separates impurities and carbon dioxide contained in biogas to generate high-temperature fuel cells. A biogas pretreatment and carbon dioxide resource fusion process module system for supplying high purity methane is disclosed. In addition, various biogas related technologies are being researched and developed.

Republic of Korea Patent Publication No. 10-2017-0050087

One technical problem to be solved by the present invention is to provide a gas purification method and system with improved efficiency of the purification process.

Another technical problem to be solved by the present invention is to provide a gas purification method and system that can remove the sulfur compound and siloxane together.

Another technical problem to be solved by the present invention is to provide a gas purification method and system easy to process design.

The technical problem to be solved by the present invention is not limited to the above.

In order to solve the above technical problem, the present invention provides a gas purification method.

According to one embodiment, the gas purification method, the target gas is introduced, a first step of removing a first gas containing carbon and sulfur from the target gas, from the target gas is performed the first step A second step of removing a second gas containing oxygen and silicon, and a third step of removing a third gas containing hydrogen and sulfur from the target gas in which the second step is performed, wherein the first step is performed. The third to third steps may be performed sequentially.

According to an embodiment of the present disclosure, the first to third steps may use a first filter including activated carbon, a second filter including silica gel, and a third filter including iron hydroxide.

According to one embodiment, each of the first to third filters includes first to third flow paths through which the target gas moves, and the length of the third flow path is greater than the length of the first and second flow paths. It may include a long one.

According to one embodiment, the amount of activated carbon included in the first filter and the amount of iron hydroxide included in the third filter may be greater than the amount of silica gel included in the second filter.

According to an embodiment of the present disclosure, the method may further include separating methane and carbon dioxide from the target gas in which the first to third steps are performed.

In order to solve the above technical problem, the present invention provides a gas purification system.

According to an embodiment, the gas purification system may include a target gas inlet, a first gas including carbon and sulfur in the target gas, a second gas including oxygen and silicon, a third gas including hydrogen and sulfur It may include a purification unit for sequentially removing, and a separation unit for separating the methane and carbon dioxide in the target gas discharged from the purification unit.

According to an embodiment of the present disclosure, the refining unit includes a first filter including activated carbon, a second filter including silica gel, and a third filter including iron hydroxide, wherein the target gas includes the first to third filters. It may include moving sequentially.

According to an embodiment, the first to third filters may include removing the first to third gases, respectively.

According to an embodiment, the first gas may include carbon disulfide, the second gas is siloxane, and the third gas may be hydrogen sulfide.

According to one embodiment, the target gas may include a biogas.

In the gas purification method according to an embodiment of the present invention, the target gas is introduced, a first step of removing the first gas containing carbon and sulfur from the target gas, the target gas is performed the first step And a third step of removing a second gas containing oxygen and silicon from the third gas, and a third step of removing a third gas containing hydrogen and sulfur from the target gas in which the second step is performed. Steps 1 to 3 may be performed sequentially. Accordingly, the purification efficiency of the target gas may be improved.

1 is a view showing a gas purification system according to an embodiment of the present invention.
2 is a flowchart illustrating a gas purification method according to an embodiment of the present invention.
3 is a view showing a purification unit included in the gas purification system according to an embodiment of the present invention.
4 is a view showing a gas purification method according to a first modification of the present invention.
5 is a view showing a gas purification method according to a second modification of the present invention.
6 is a view showing a gas purification method according to a third modification of the present invention.
7 is a view showing gas purification methods according to embodiments and comparative examples of the present invention.
8 is a graph showing adsorption characteristics for biogas of the gas purification method according to Example 1 of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical idea of the present invention is not limited to the exemplary embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed contents are thorough and complete, and that the spirit of the present invention can be sufficiently delivered to those skilled in the art.

In the present specification, when a component is mentioned to be on another component, it means that it may be formed directly on the other component or a third component may be interposed therebetween. In addition, in the drawings, the thicknesses of films and regions are exaggerated for effective explanation of technical contents.

In addition, in various embodiments of the present specification, terms such as first, second, and third are used to describe various components, but these components should not be limited by these terms. These terms are only used to distinguish one component from another. Thus, what is referred to as a first component in one embodiment may be referred to as a second component in another embodiment. Each embodiment described and illustrated herein also includes its complementary embodiment. In addition, the term 'and / or' is used herein to include at least one of the components listed before and after.

In the specification, the singular encompasses the plural unless the context clearly indicates otherwise. In addition, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, element, or combination thereof described in the specification, and one or more other features or numbers, steps, configurations It should not be understood to exclude the possibility of the presence or the addition of elements or combinations thereof. In addition, the term "connection" is used herein to mean both indirectly connecting a plurality of components, and directly connecting.

In addition, in the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 is a view showing a gas purification system according to an embodiment of the present invention.

Referring to FIG. 1, the gas purification system according to the embodiment may include a target gas inlet 100, a purifier 200, and a separator 300.

The target gas inlet 100 may introduce the target gas 10 from the outside. The introduced target gas 10 may be supplied to the purification unit 200. For example, the target gas 10 may be biogas.

The purification unit 200 may remove the first gas, the second gas, and the third gas. According to one embodiment, the first gas may include carbon and sulfur. For example, the first gas may be carbon disulfide (CS ₂ ) or carbonyl sulfide (COS). According to one embodiment, the second gas may include oxygen and silicon. For example, the second gas may be siloxane. According to one embodiment, the third gas may include hydrogen and sulfur. For example, the third gas may be hydrogen sulfide (H ₂ S).

The purification unit 200 may include a first filter, a second filter, and a third filter. According to one embodiment, the first filter may include activated carbon. According to one embodiment, the second filter may include silica gel. According to one embodiment, the third filter may include iron hydroxide.

The first to third filters may remove the first to third gases, respectively. That is, when the first gas is carbon disulfide or carbonyl sulfide, it may be removed by activated carbon in the first filter. When the second gas is siloxane, it may be removed by silica gel in the second filter. When the third gas is hydrogen sulfide, it may be removed by iron hydroxide in the third filter.

The target gas 10 may sequentially move the first to third filters. Accordingly, first to third gases included in the target gas 10 may be sequentially removed. The target gas 10 from which the first to third gases are removed may be discharged from the purification unit 200 and introduced into the separation unit 300.

The separation unit 300 may separate methane and carbon dioxide in the target gas 10 discharged from the purification unit 200. More specifically, the target gas 10 from which the first to third gases are removed through the purification unit 200 may include methane and carbon dioxide. The separation unit 300 may separate methane and carbon dioxide in the target gas 10 from which the first to third gases are removed. According to an embodiment, the separated methane gas may be used as a fuel of a solid oxide fuel cell (SOFC).

Hereinafter, a process of removing the first to third gases in the above-described purification unit 200 will be described with reference to FIGS. 2 and 3.

2 is a flowchart illustrating a gas purification method according to an embodiment of the present invention, Figure 3 is a view showing a purification unit included in the gas purification system according to an embodiment of the present invention.

2 and 3, the target gas 10 may be introduced into the purification unit 200 (S110). The purification unit 200 may be composed of an adsorption module 250 including the first filter 210, the second filter 220, the third filter 230, and the diaphragm 240. .

When the target gas 10 is introduced into the purification unit 200, the first gas may be removed (S120). The first to third gases may be sequentially removed. The first gas may be removed by the first filter 210. The target gas 10 from which the first gas is removed may have the second gas removed (S130). The second gas may be removed by the second filter 220. In the target gas 10 from which the second gas is removed, the third gas may be removed (S140). The third gas may be removed by the third filter 220.

The first to third gas and the target gas 10 may be the same as the first to third gas and the target gas 10 in the gas purification system described with reference to FIG. 1. The first to third filters 210, 220, 230 may also be the same as the first to third filters in the gas purification system described above.

The first to third filters 210, 220, and 230 may include first to third flow path parts 210a, 220a, and 230a through which the target gas 10 moves, respectively. The target gas 10 may move in a length direction of the first to third flow path parts 210a, 220a, and 230a. Accordingly, the first to third gases may be sequentially removed while the target gas 10 passes through the first to third flow path parts 210a, 220a, and 230a.

According to one embodiment, the amount of activated carbon, silica gel, and iron hydroxide in the first to third filters 210, 220, and 230 is the length L ₁ of the first to third flow path parts 210a, 220a, and 230a. , it can be adjusted to the L _2, L _3). Specifically, as the lengths L ₁ , L ₂ , and L _{3 of} the first to third flow path parts 210a, 220a, and 230a become longer, the first to third filters 210, 220, and 230 may be formed. The amount of activated carbon, silica gel, and iron hydroxide can be increased.

According to one embodiment, the second length (L ₃₎ of the third flow passage (230a) is, may be longer than the length (L _1, L ₂₎ of said first and second flow passage portion (210a, 220a). According to one embodiment, the length (L ₂₎ of the length (L ₁₎ and the second flow passage portion (220a) of the first flow passage (210a) may be equal to each other. For example, the lengths L ₁ and L _{2 of} the first and second flow path parts 210a and 220a may be 10 mm, respectively. For example, the length L ₃ of the third flow path part 230a may be 20 mm.

According to one embodiment, when the target gas 10 is a biogas, as the third gas is greater than the first and second gases in the target gas 10, the first filter 210 may be The amount of iron hydroxide included in the third filter 230 may be greater than the amount of activated carbon and the amount of silica gel included in the second filter 220.

That is, when the target gas 10 is a biogas, as the third gas is larger than the first and second gases in the target gas 10, the amount of removal of the third gas may be greater than that of the first gas. It may be more than the removal amount.

The first to third filters 210, 220, and 230 may be separated by the diaphragm 240, respectively. That is, the diaphragm 240 may be disposed between the first and second filters 210 and 220 and between the second and third filters 220 and 230. According to one embodiment, the diaphragm 240 may be a porous membrane.

As the diaphragm 240 is disposed between the first and second filters 210 and 220, the activated carbon in the first filter 210 and the silica gel in the second filter 220 are mixed. Can be prevented. In addition, as the diaphragm 240 is disposed between the second and third filters 220 and 230, the silica gel in the second filter 220 and the iron hydroxide in the third filter 230 are mixed. Can be prevented.

Methane and carbon dioxide may be separated from the target gas 10 from which the first to third gases are removed. According to one embodiment, the separated methane can be used as fuel for SOFC.

Unlike the gas purification method according to the embodiment of the present invention described above, when the target gas 10 is not removed in the order of the first gas, the second gas, and the third gas, the removal rate of hydrogen sulfide is lowered Thus, a problem may occur in which the purification efficiency is reduced.

However, the gas purification method according to an embodiment of the present invention, the step of introducing the target gas 10, the first step of removing the first gas containing carbon and sulfur from the target gas 10, the A second step of removing the second gas containing oxygen and silicon from the target gas 10 on which the first step was performed, and hydrogen and sulfur from the target gas 10 on which the second step was performed Including a third step of removing the third gas, the first to third steps may be performed sequentially.

Accordingly, the concentration of the third gas in the target gas 10 from which the first and second gases are removed may be increased. When the third gas is hydrogen sulfide, the removal rate of hydrogen sulfide has a greater influence on the mass transfer rate due to diffusion from hydrogen sulfide to iron hydroxide than the chemical reaction rate occurring on the surface of the iron hydroxide, thereby improving the removal rate of hydrogen sulfide with increased concentration. . As a result, the purification efficiency of the target gas 10 may be improved.

In addition, in the gas purification method according to the embodiment, immediately after the second step of removing the second gas is performed (directly after), as the third step of removing the third gas is performed, the target gas ( Purification efficiency of 10) can be improved.

Hereinafter, various modifications for performing the gas purification method according to the above-described embodiment will be described with reference to FIGS. 4 to 6.

4 is a view showing a gas purification method according to a first modification of the present invention, Figure 5 is a view showing a gas purification method according to a second modification of the present invention, Figure 6 is a view of the present invention It is a figure for showing the gas purification method which concerns on a 3rd modification.

Referring to FIG. 4, the gas purification method according to the first modification of the present invention may be performed through the first to third adsorption modules 250a, 250b, and 250c. According to an embodiment, the first to third adsorption modules 250a, 250b, and 250c may include first to third filters 210, 220, and 230, respectively. The first to third adsorption modules 250a, 250b, 250c may be spaced apart from each other. The first to third filters 210, 220, and 230 may be as described with reference to FIGS. 2 and 3.

Accordingly, the target gas 10 is the first to third filters 210, 220 and 230 included in the first to third adsorption modules 250a, 250b and 250c, respectively. 3 gases can be removed sequentially.

Referring to FIG. 5, the gas purification method according to the second modification of the present invention may be performed through the first and second adsorption modules 250a and 250b. According to one embodiment, the first adsorption module 250a is disposed between the first filter 210, the second filter 220, and the first filter 210 and the second filter 220. The diaphragm 240 may be included. According to one embodiment, the second adsorption module 250b may include the third filter 230. The first and second adsorption modules 250a and 250b may be spaced apart from each other. The first to third filters 210, 220, and 230 may be as described with reference to FIGS. 2 and 3.

Accordingly, in the target gas 10, the first and second gases may be sequentially removed from the first and second filters 210 and 220 included in the first adsorption module 250a, respectively. . The target gas 10 from which the first and second gases are removed may move to the second adsorption module 250b, and the third gas may be removed from the third filter 230.

Referring to FIG. 6, the gas purification method according to the third modified example of the present invention may be performed through the first and second adsorption modules 250a and 250b. According to one embodiment, the first adsorption module 250a may include the first filter 210. According to one embodiment, the second adsorption module 250b is disposed between the second filter 220, the third filter 230, and the second filter 220 and the third filter 230. The diaphragm 240 may be included. The first and second adsorption modules 250a and 250b may be spaced apart from each other. The first to third filters 210, 220, and 230 may be as described with reference to FIGS. 2 and 3.

Accordingly, in the target gas 10, the first gas may be removed from the first filter 210 included in the first adsorption module 250a. The target gas 10 from which the first gas is removed is moved to the second adsorption module 250b so that the second and third gases are sequentially formed in the second and third filters 220 and 230. Can be removed.

Hereinafter, specific experimental methods and characteristics evaluation results of the gas purification method according to the above-described embodiment will be described.

Gas purification method according to Example 1

A first filter 210 having a length of 10 mm and including activated carbon, a second filter 220 having a length of 10 mm and containing silica gel, and a third filter 230 having a length of 20 mm and containing iron hydroxide are prepared. The first filter 210, the second filter 220, and the third filter 230 are disposed in the adsorption module in order.

Then, 60 wt% CH ₄ , 40 wt% CO ₂ , 1900 ppm H ₂ S, 100 ppm COS, 100 ppm CS ₂ , 10 ppm siloxane D4, and 20 ppm siloxane D5 The biogas containing was purified by providing the adsorption module at a rate of 300 mL / min.

Gas purification method according to Comparative Example 1

The biogas was purified by the method according to Example 1 described above, but the second filter 220, the first filter 210, and the third filter 230 were sequentially disposed in the adsorption module.

Gas purification method according to Comparative Example 2

The biogas was purified by the method according to Example 1, but the third filter 230, the first filter 210, and the second filter 220 were disposed in the adsorption module in order.

Gas purification method according to Comparative Example 3

The biogas was purified by the method according to the first embodiment described above, but the third filter 230, the second filter 220, and the first filter 210 were sequentially disposed in the adsorption module.

Gas purification method according to Comparative Example 4

The biogas was purified by the method according to Example 1 described above, but the first filter 210, the third filter 230, and the second filter 220 were disposed in the adsorption module in order.

Gas purification method according to Comparative Example 5

The biogas was purified by the method according to Example 1 described above, but the second filter 220, the third filter 230, and the first filter 210 were sequentially disposed in the adsorption module.

Gas purification methods according to Example 1 and Comparative Examples 1 to 5 are summarized in Table 1 below.

division rescue Example 1 First Filter-Second Filter-Third Filter Comparative Example 1 Second Filter-First Filter-Third Filter Comparative Example 2 Third Filter-First Filter-Second Filter Comparative Example 3 Third Filter-Second Filter-First Filter Comparative Example 4 First Filter-Third Filter-Second Filter Comparative Example 5 Second Filter-Third Filter-First Filter

7 is a view showing gas purification methods according to embodiments and comparative examples of the present invention.

Referring to (a) to (f) of FIG. 7, the biogas is purified by the gas purification method according to Example 1 and Comparative Examples 1 to 5, and adsorption capacity (mg / g) of substances included in the purified biogas ) And the time (min) required for detection according to the substance in the purified biogas. The adsorption capacity and the detection time were based on the time when the materials included in the purified biogas had a concentration of 0.1 wt% compared to the materials included in the initial biogas. (A)-(f) of FIG. 7 show the gas purification method which concerns on the said Example 1, the comparative example 1-the comparative example 5, respectively.

The characteristics of the biogas purified by the gas purification method according to Example 1 and Comparative Examples 1 to 5 are summarized through Table 2 below.

division characteristic CH ₄ CO ₂ H ₂ S COS CS ₂ Siloxane
(D4) Siloxane
(D5) Example 1 Adsorption capacity
(mg / g) 0 0 92.9 0.3 5.6 18.1 45.3 Detection time
(min) - - 138.5 0.2 87.4 - - Comparative Example 1 Adsorption capacity
(mg / g) 0 0 86.0 0.3 4.1 18.1 45.3 Detection time
(min) - - 113.8 0.2 26.4 - - Comparative Example 2 Adsorption capacity
(mg / g) 0 0 68.4 0.4 5.1 18.1 45.3 Detection time
(min) - - 87.8 0.2 43.9 - - Comparative Example 3 Adsorption capacity
(mg / g) 0 0 78.5 0.3 4.5 18.1 45.3 Detection time
(min) - - 77.3 0.2 43.8 - - Comparative Example 4 Adsorption capacity
(mg / g) 0 0 82.8 0.4 4.2 18.1 45.3 Detection time
(min) - - 105.0 0.2 61.3 - - Comparative Example 5 Adsorption capacity
(mg / g) 0 0 70.79 0.5 5.0 18.1 45.3 Detection time
(min) - - 106.3 0.2 26.4 - -

As can be seen in Table 2 above, when the biogas was purified by the gas purification method according to Example 1, the adsorption capacity (mg / g) of the substances included in the purified biogas was the highest and was purified. It was confirmed that the time (min) required for detection in the biogas according to the substance was the longest.

Accordingly, it can be seen that the gas purification method according to Example 1 is more efficient for purifying biogas than the gas purification method according to Comparative Examples 1 to 5. That is, in the case of purifying biogas, it can be seen that it is efficient to configure carbon disulfide and carbonyl sulfide, siloxane, and hydrogen sulfide in the order of removal.

8 is a graph showing adsorption characteristics for biogas of the gas purification method according to Example 1 of the present invention.

8, the above embodiment the amount of the initial material in the purification of the biogas to the gas purification method, and a biogas according to 1 (C ₀₎ represents the amount (C) of the purified material in the preparation of biogas according to the time It was.

As can be seen in Figure 8, the amount of carbonyl sulfide (COS) purified compared to the amount of carbonyl sulfide (COS) is the same (C / C ₀ = 1), the time required is 500 minutes, the initial carbon disulfide both compared to the time amount is equal takes makin of purified carbon disulfide (CS2) of the (CS ₂₎ is shown as 1500 minutes, like the amount of the initial hydrogen sulfide amount compared to purified hydrogen sulfide (H ₂ S) in the (H ₂ S) The time taken to build was found to be 5500 minutes. Accordingly, when the biogas is purified by the gas purification method according to the first embodiment, it can be seen that hydrogen sulfide in the biogas takes the longest time.

As mentioned above, although this invention was demonstrated in detail using the preferable embodiment, the scope of the present invention is not limited to a specific embodiment, Comprising: It should be interpreted by the attached Claim. In addition, those skilled in the art should understand that many modifications and variations are possible without departing from the scope of the present invention.

10: target gas
100: target gas inlet
200: refiner
210, 220, 230: first filter, second filter, third filter
210a, 220a, 230a: 1st flow path, 2nd flow path, 3rd flow path
240: diaphragm
250: adsorption module
250a, 250b, 250c: first adsorption module, second adsorption module, third adsorption module
L ₁ , L ₂ , L ₃ : length of first flow path, length of second flow path, length of third flow path
300: separation part

Claims (10)

Introducing a target gas;
A first step of removing a first gas containing carbon and sulfur from the target gas;
A second step of removing a second gas including oxygen and silicon from the target gas in which the first step is performed; And
A third step of removing a third gas comprising hydrogen and sulfur from the target gas from which the second step is performed using a third filter comprising iron hydroxide,
Gas purification method in which the first to third steps are performed sequentially.
According to claim 1,
The first and second steps, respectively
A first filter comprising activated carbon; And
A gas purification method using a second filter comprising silica gel.
The method of claim 2,
The first to third filters each include first to third flow paths through which the target gas moves,
The length of a said 3rd flow path is a gas purification method containing longer than the length of the said 1st and 2nd flow path.
The method of claim 2,
A method of purifying a gas comprising a greater amount of iron hydroxide included in the third filter than an amount of activated carbon included in the first filter and an amount of silica gel included in the second filter.
According to claim 1,
Separating methane and carbon dioxide from the target gas in which the first to third steps are performed.
A target gas inlet;
A purifying unit sequentially removing the first gas including carbon and sulfur in the target gas, the second gas including oxygen and silicon, and the third gas including hydrogen and sulfur; And
Including a separation unit for separating the methane and carbon dioxide in the target gas discharged from the purification unit,
The purifying unit includes a third filter including iron hydroxide, wherein the third gas is removed by the third filter.
The method of claim 6,
The purification unit,
A first filter comprising activated carbon; And
Including a second filter comprising a silica gel,
And said target gas moves sequentially through said first to third filters.
The method of claim 7, wherein
The first to third filters, respectively, the gas purification system comprising removing the first to third gases.
The method of claim 6,
Wherein said first gas is carbon disulfide, said second gas is siloxane, and said third gas is hydrogen sulfide.
The method of claim 6,
And said target gas is biogas.

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