KR101869461B1 - Method for removing oxygen in methane mixture gas by using oxygen catalyst, perovskite type oxygen removing catalyst used in the same, and land fill gas refine device applying land fill gas mathane direct converting technology using the same - Google Patents

Abstract

The present invention provides a process for producing a perovskite catalyst, comprising: providing a perovskite catalyst in a reaction vessel comprising La _1-x Sr _x Co _1-y Fe _y O ₃ -δ; Heating the reaction vessel; And removing the oxygen in the methane mixture gas as the methane gas is completely burned by the perovskite catalyst when the methane gas mixture is introduced into the reactor while the reactor is in a heated state , A method for removing oxygen from a methane mixed gas using an oxygen scavenging catalyst, a perovskite oxygen scavenging catalyst used therefor, and a landfill gas refining apparatus using the methane direct conversion technology.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for removing oxygen from a methane mixed gas using an oxygen scavenging catalyst, a perovskite oxygen scavenging catalyst used therein, and a landfill gas methane direct conversion technology using the catalyst, CATALYST, PEROVSKITE TYPE OXYGEN REMOVING CATALYST USED IN THE SAME, AND LAND FILL GAS REFINE DEVICE APPLYING LAND FILL GAS MATHANE DIRECT CONVERTING TECHNOLOGY USING THE SAME}

The present invention relates to a method for removing oxygen from a methane mixed gas using an oxygen scavenging catalyst, a perovskite oxygen scavenging catalyst used therefor, and a landfill gas refining apparatus employing the direct gas methane direct conversion technology using the same.

In a variety of industrial processes, syngas (CO + H ₂ ) is produced through partial oxidation, in which a trace amount of oxygen must act as impurities and be removed. In the case of landfill gas, complaints arise because the gas is released to the surrounding area as the surface of the landfill emits. In order to suppress this, the amount of forced capture of the landfill gas (LFG) is increased. In this process, oxygen (O ₂ ) and nitrogen (N ₂ ) in the landfill gas are increased . This is a cause of deterioration of the quality of the trapped gas. In particular, methane, oxygen, silicon, chlorine, water, sulfur compounds and dusts cause corrosion in the contact area of the engine generator and promote mechanical wear when the generator using the landfill gas is operated, In addition, the utilization rate, utilization rate, maintenance cycle, parts replacement cycle and operation maintenance cost of the generator can be greatly influenced. Currently, commercially available oxygen removal and production technology is an oxygen production technology through nitrogen adsorption using a zeolite adsorbent, and a technique for adsorbing and removing only oxygen itself has not been commercialized yet. Furthermore, because oxygen adsorption usually occurs at low temperatures, oxygen adsorption techniques that are adsorbed at high temperatures have not been developed. However, since DME (dimethyl ether) is produced at a high temperature (700 ° C. or more and 1000 ° C. or less) when producing syngas by gasification or using LFG, a technique for removing trace amounts of oxygen at high temperature It is necessary.

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Currently, most of the oxygen separation technology is applied to the adsorption separation technology, the membrane separation technology and the deep cooling separation technology. Conventional oxygen separation techniques are consuming a lot of energy for oxygen separation, and it is not easy to remove trace amounts of oxygen in the methane mixture gas.

The present invention relates to a method for removing oxygen from a methane mixed gas using an oxygen scavenging catalyst that maximizes oxygen scavenging efficiency by promoting a complete combustion reaction on oxygen contained in a methane gas mixture such as landfill gas, And a landfill gas purification system using the methane direct conversion technology using the same.

In order to solve the above problems, a method for removing oxygen from a methane mixture gas using an oxygen scavenging catalyst, which is one embodiment of the present invention, includes La _1-x Sr _x Co _{1 -y} Fe _y O _3-δ Providing a perovskite catalyst; Heating the reaction vessel; And introducing a methane mixture gas into the reaction vessel while the reaction vessel is heated, removing oxygen in the methane mixture gas as methane in the methane mixture gas is completely burned by the perovskite catalyst .

Here, the perovskite catalyst may include one of powder, pellet, and bead.

Here, the perovskite catalyst may be prepared by contacting gamma-alumina with a solution in which La _1-x Sr _x Co _{1 -y} Fe _y O _{3 -δ} is dissolved, followed by drying and calcining.

Here, the step of heating the reaction tank may include a step of heating the perovskite catalyst to 300 to 600 ° C.

Here, the perovskite catalyst may be prepared by one of a high-temperature calcination method, a citric acid method, and a complex polymerization method.

Where 0.7? X? 0.9.

Where x = 0.9, y = 0.8, x = 0.9, y = 0.5, x = 0.9, y = 0.9, and x = 0.9, y = 0.1.

Meanwhile, the perovskite oxygen scavenger, which is another embodiment of the present invention, comprises La _1-x Sr _x Co _{1 -y} Fe _y O _{3 -δ} wherein x is 0? X? 1 and y is 0? Y? And δ is in the range of 0 ≦ δ <2) to promote the complete combustion reaction for oxygen in the methane mixture gas.

Here, the perovskite catalyst can completely remove methane and oxygen in the methane mixture gas at 300 to 600 ° C to remove oxygen in the methane mixture gas.

In addition, another embodiment of the present invention is directed to a landfill gas purification system using a direct methane conversion technology for landfill gas, comprising: a landfill gas collection device installed in a landfill to collect landfill gas; An ammonia and hydrogen sulfide removal device for removing ammonia and hydrogen sulfide from the captured landfill gas; A water and dust removing device for removing moisture and fine dust from the first purification buried gas firstly purified by the ammonia and hydrogen sulfide removing device; An apparatus for removing siloxane from a second purified landfill gas which is secondarily purified by the water and dust removing apparatus; Wherein La is at least _{one selected} from the group consisting of La _1-x Sr _x Co _1-y Fe _y O _3-δ wherein x is 0 ≤ x ≤ 1 and y is 0 ≤ y 1 < / RTI &gt; and &lt; RTI ID = 0.0 &gt;#&lt; / RTI &gt; A nitrogen removal device for removing nitrogen from the fourth purification buried gas which is quadratically purified by the oxygen removal device; And a storage tank for storing the fifth purification buried gas that has been fifthly purified by the nitrogen removal device.

Here, the oxygen remover may heat the interior of the perovskite catalyst to 300 to 600 ° C to cause a complete combustion reaction of methane and oxygen in the third purified landfill gas, Oxygen can be removed.

Where x = 0.9 and y = 0.8.

When the perovskite oxygen scavenging catalyst according to the present invention is used, the complete combustion reaction between methane gas and oxygen can be promoted at a middle low temperature of 300 to 600 ° C. Accordingly, methane gas containing a small amount of oxygen such as landfill gas It is possible to quickly remove only oxygen from the mixed gas, thereby reducing the risk of industrial accidents due to oxygen during operation of the landfill gas refining apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic explanatory view showing the entire construction of a landfill gas purification apparatus to which a landfill gas methane direct conversion technology, which is an embodiment of the present invention, is applied; FIG.
2 is a conceptual diagram illustrating the structure of perovskite and the induction of oxygen deficiency in accordance with one embodiment of the present invention.
3 is a diagram for comparing the composition of landfill gas and prior gas relative to an embodiment of the present invention.
4 is a graph comparing the specific surface area of La _0.1 Sr _0.9 Co _0.2 Fe _0.8 , which is an embodiment of the present invention, according to a manufacturing method.
FIG. 5 is an SEM image of La _0.1 Sr _0.9 Co _0.2 Fe _0.8 powder prepared according to the citric acid method and the high-temperature firing method. FIG. 5 a is an SEM image of the powder prepared by the citric acid method, and FIG. SEM image of a powder.
6 is a graph showing oxygen adsorption performance of LSCF powders synthesized while varying the composition of x and y by temperature.
7 is a graph showing oxygen conversion rates of LSCF powders synthesized while varying the composition of x and y by temperature.
8 is a graph showing the results of a methane oxidation experiment when 4 g of La _0.1 Sr _0.9 Co _0.2 Fe _0.8 according to an embodiment of the present invention is used.
9 is a graph showing the results of a methane oxidation experiment when 1 g of La _0.1 Sr _0.9 Co _0.2 Fe _0.8 according to an embodiment of the present invention is used.
10 is a flowchart for explaining a method for removing oxygen in a methane mixture gas using an oxygen scavenger catalyst according to an embodiment of the present invention.

Hereinafter, a method for removing oxygen from a methane mixed gas using an oxygen scavenging catalyst according to the present invention, a perovskite oxygen scavenging catalyst used therein, and a landfill gas purification system using the methane direct conversion technology using the same will be described with reference to the drawings. Will be described in more detail

In the present invention, the perovskite oxygen scavenging catalyst is La _1-x Sr _x Co _{1 -y} Fe _y O _3-δ wherein x is 0 ≤ x ≤ 1, y is 0 ≤ y ≤ 1, and δ is 0 ≤ δ &Lt; 2).

On the other hand, the perovskite of La _0.1 Sr _0.9 Co _0.2 Fe _0.8 is abbreviated as LSCF 1928, La _0.1 Sr _0.9 Co _0.5 Fe _0.5 is LSCF1955, La _0.1 Sr _0.9 Co _0.9 Fe _0.1 is LSCF1991, and La _0.1 Sr _0.9 Co _0.1 Fe _0.9 should be referred to briefly as LSCF1919.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic explanatory diagram showing an overall configuration of a landfill gas purification apparatus to which a direct methane conversion technology for landfill gas, which is an embodiment of the present invention, is applied. 1, the landfill gas purification apparatus using the landfill gas methane direct conversion technology, which is an embodiment of the present invention, includes a landfill gas collecting apparatus 100, an ammonia and hydrogen sulfide removing apparatus 200, (DME) plant, a DME storage tank 800, and a DME (DME) storage tank 800. The DME storage tank 800 is connected to an inhalation desorption apparatus 400, an oxygen removal apparatus 500, a nitrogen removal apparatus 600, Or the purified gas transportation vehicle 900 may be constructed.

Here, the landfill gas collecting apparatus 100 is for collecting the landfill gas generated in a landfill or the like, and serves to transfer the landfill gas buried in the ground through the pump to the ground.

Generally, the landfill gas generated from landfills is mainly composed of methane and carbon dioxide, and contains about 5 to 10% of impurities. These impurities include nitrogen <10%, oxygen <1%, sulfur compounds 500-1000ppm, siloxanes 100-150ppm, VOCs, fine dust, etc., which impair their performance as impurities in DME or refinery gas to be finally produced .

Therefore, in the present invention, these impurities are removed through the following apparatuses.

The primary removal is hydrogen sulphide and ammonia, which is removed by the ammonia and hydrogen sulphide removal apparatus 200. A wet catalytic desulfurization technique is first applied to treat relatively high concentrations of hydrogen sulfide (<several hundred ppm) among the landfill gas trace materials. According to this method, hydrogen sulfide and ammonia in the landfilled gas are dissolved in water, and then hydrogen sulfide and ammonia are removed by converting the desulfurization catalyst into a harmless and odorless substance at normal temperature and pressure through a liquid phase oxidation reaction of the desulfurization catalyst. At this time, the removed hydrogen sulfide is converted into sulfur particles and fixed to the catalyst, and the discharged spent catalyst can be used as general waste after landfilling or as fertilizer after dehydration. On the other hand, when a Fe-based catalyst is used for the oxidation reaction of hydrogen sulfide, it is more economical than the catalyst used in the conventional liquid acid catalytic oxidation method for removing hydrogen sulfide, and no harmful waste is generated.

Then, fine dust and moisture are removed by a water and dust removing device (inertial collision type dust removing device: 300).

Then, the siloxane is removed by the infiltration desorption apparatus 400.

Then, the oxygen in the landfill gas is removed through the oxygen remover 500. If this oxygen is included in the refining gas at a later time, there is a fear of explosion, and furthermore, it is a constituent element for corroding the metal pipe as the transfer passage, so it should be removed. In this oxygen remover 500, oxygen can be removed using a metal oxide having an oxygen vacancy (perovskite oxygen scavenger).

In the case of the closed-skit metal oxide (ABO ₃ type oxide), A is a metal cation in the alkaline earth metal system (periodic table atomic number 57-71 cationic, 1A, 2A series metal) 6 and combines with three oxygen anions (-6) to achieve electrical neutrality. If the atoms substitute for or substitute other A 'and B' atoms for A and B, then oxygen ions become insufficient to meet the electrical neutrality and thus oxygen vacancy is generated. At this time, the whole oxide crystal is electrically stable, but the lattice around the oxygen vacancy is maintained in a electrically charged state (partially charged δ +), so that when the external oxygen partial pressure is increased, oxygen is absorbed into the lattice.

This reverse circulation deoxygenation technology absorbs oxygen using the absorber in which the oxygen vacancy is present, and the oxygen is completely oxidized with methane gas, which is a main component of the landfill gas (that is, As a catalyst), oxygen is removed from the landfill gas.

The nitrogen removal device 600 is for removing nitrogen in the landfill gas. The nitrogen is adsorbed by using zeolite to remove nitrogen in the landfill gas.

In the landfill gas purification system according to an embodiment of the present invention, ammonia and hydrogen sulfide in the captured landfill gas are firstly removed through the ammonia and hydrogen sulfide removal device 200, and the ammonia and hydrogen sulfide removal device 200 In the first purified landfill gas, the moisture and fine dust are removed through the inertial collision type dust removing apparatus 300, and the second purified landfill by the inertial collision type dust removing apparatus 300 In the gas, the siloxane is removed by the inhalation desorption apparatus 400, oxygen is removed by the oxygen elimination apparatus 500 in the third purification buried gas thirdly purified by the in vivo adsorption elimination apparatus 400 , The nitrogen is removed by the nitrogen removal device 600 in the fourth purification buried gas fourthly purified by the oxygen removing device 500, and the fifth purified buried gas finally purified is generated All.

The fifth purified landfill gas is converted into dimethyl ether gas in the DME plant 700 and stored in the DME storage tank 800 or the fifth purified gas is separately liquefied and loaded on the purified gas transportation vehicle 900 It may be transferred to the place of use.

Hereinafter, the structure of the perovskite metal oxide used in the oxygen scavenger will be described in more detail with reference to FIG.

2 is a conceptual diagram for explaining the structure of perovskite and the induction of oxygen deficiency according to an embodiment of the present invention. As shown in FIG. 2, the perovskite oxygen adsorbent according to the present invention operates on the principle of selectively adsorbing only oxygen by inducing oxygen deficiency in the oxide lattice at a high temperature using a perovskite structure. In order to induce oxygen deficiency, various other ions are doped to produce a solid solution oxide, which is used as an oxygen adsorbent. When oxygen is adsorbed and heated to 300 to 600 ° C under a methane gas atmosphere, methane gas and oxygen are completely burned. Oxygen in the landfill gas is removed by this reaction.

The composition ratio of the landfill gas to be subjected to oxygen removal in the present invention will be described with reference to Fig.

3 is a diagram for comparing the composition of landfill gas and natural gas according to an embodiment of the present invention. As shown in Fig. 3, in the case of the landfill gas to be compared, the oxygen content is as high as 0.1 to 2.0%. When the landfill gas containing a large amount of oxygen is used, the contact portion of the engine generator is corroded, mechanical wear is promoted, and the output of the power generation facility is reduced. In such a case, the risk of fire increases. In such a landfill gas, oxygen should be reduced to less than 0.1%, and it should be made similar to natural gas, which will increase the value of utilization as fuel.

FIG. 4 is a graph comparing the specific surface area of La _0.1 Sr _0.9 Co _0.2 Fe _0.8 , which is an embodiment of the present invention, according to a manufacturing method. In La _1-x Sr _x Co _{1 -y} Fe _y O ₃ -δ which is one embodiment of the present invention, there are various factors that determine the oxygen adsorption power, and in particular, the specific surface area is very important.

As a method for producing perovskite such as La _1-x Sr _x Co _{1 -y} Fe _y O _3-δ , there are a citric acid method (CM) and a high-temperature calcination method.

The citrate method is a method in which citric acid is selected as a chelating agent material to hold various metal constituent ions present in a solution so that perovskite can be formed. As a starting material _{La (NO 3) 3 · 6H} 2 O ( purity of 99.9% or more, Aldrich, USA), Sr ( NO 3) 2 ( a purity of 99% or more, Aldrich, USA), Co ( NO 3) · 6H 2 O (Purity greater than 98%, Aldrich, USA) and Fe (NO ₃ ) ₃ .9H ₂ O (purity greater than 98%, Aldrich, USA) In the citric acid method, the mass was measured according to the stoichiometry, and then dissolved in distilled water to prepare a total 0.1 M solution. Citric acid (purity: 99.5%, SAMCHUN, Korea ). The mixed solution was reacted at a temperature of 100 ° C. for about 4 hours on a magnetic stirrer, and then a brown gel was obtained by evaporating the water at 80 ° C. The gel-like sample was dried at 110 ° C. for 24 hours, To prepare a precursor. After removal of moisture at 180 ° C, the precursor is decomposed at 250-450 ° C and the carbonate is decomposed at 800 ° C for 2 hours and sintered at 1300 ° C for 5 hours to produce perovskite oxide.

In the high-temperature firing method, La, Sr, Co, Fe were weighed in accordance with stoichiometry using La ₂ O ₃ , SrCo ₃ , Co ₃ O ₄ and Fe ₂ O ₃ as initial raw materials. The powder was dried at 70 ℃ for 24 hours. The powder was sintered at 900 ℃ for 5 hours and the final perovskite powder was prepared.

The results of the BET analysis of the LSCF1928 powder prepared by the citric acid method (CM) and the high-temperature firing method (SM) are shown. The citric acid method has a high specific surface area of 0.65 m2 / g because of no pulverization process, and thus has a high value to be adopted as an adsorbent / catalyst. However, the LSCF1928 powder prepared by the high-temperature calcination method has a surface area of 6.95 m &lt; 2 &gt; / g in spite of the high temperature calcination and is suitable for being adopted as an adsorbent / catalyst. This will become more apparent from the SEM image of Fig.

5A is an SEM photograph (LSCF1928 at 5000 magnification and 5000 magnification at left magnification), and FIG. 5B is an SEM photograph (LSCF1928 at left magnification is 5000 magnification, And the right image is 500 times magnification). As shown, it had a particle size of about 30 to 50 mu m and its shape was not uniform. However, the LSCF1928 powder prepared by the high - temperature sintering method has not only a very small particle size of about 0.5 ~ 3 ㎛ but also all the grains are uniformly and evenly distributed.

On the other hand, when La has a value of 0.7 to 0.9 in La _1-x Sr _x Co _{1 -y} Fe _y O ₃ -δ, the oxygen adsorption force is enhanced. That is, it can be seen that the oxygen adsorption power is enhanced as the Sr component is larger than the La component. Accordingly, the perovskite catalyst may be x = 0.9, y = 0.8 (LSCF1928), x = 0.9, y = 0.5 (LSCF1955), x = 0.9, y = 0.9 0.1 (LSCF1991).

FIG. 6 is a graph showing oxygen adsorption performance of LSCF powder synthesized by varying the composition of x and y by temperature. The average adsorption amount in each temperature range when the breakthrough curve was drawn using LSCF1919, LSCF1955, and LSCF1991 powders as well as LSCF1928 was calculated and shown in FIG. In the case of LSCF1919, the maximum oxygen adsorption amount at 600 ° C was 6.62 ml O ₂ / g. The amount of adsorption increased with increasing temperature from 300 ° C, but the amount of oxygen adsorption decreased again in the temperature region exceeding 600 ° C. Similarly LSCF1928 powder even at 600 ℃ as 8.08 ml O ₂ / g compared with other powder corresponds to a high value. As the temperature increases from 300 ° C, the amount of oxygen adsorption also increases, but it tends to decrease rather than 600 ° C. The two powders have the highest adsorption characteristics at 600, but the rest are different in LSCF1955 and LSCF1991. The LSCF1955 powder showed the highest oxygen adsorption amount (7.17 ml O ₂ / g) at 500 ° C, but the oxygen adsorption amount also maintained at a certain level when the temperature increased to 600 ° C or higher. LSCF1991 had the highest amount of oxygen adsorption (11.37 ml O ₂ / g) than the above-mentioned powders. The temperature was also 400 ° C, which was lower than other powders.

As described later, the reaction temperature at which the object of the present invention is completely combusted with oxygen and methane in the landfill gas is 300 to 550 ° C., and thus, the LSCF1928 powder having the highest oxygen adsorption amount at 300 to 600 ° C., It will be most suitable as an oxygen scavenging catalyst.

FIG. 7 is a graph showing oxygen conversion rates of LSCF powders synthesized while varying the composition of x and y. FIG. 7, the oxygen conversion is represented by the vertical axis and the horizontal axis is represented by the temperature (0 to 600 ° C).

7, (a) shows LSCF1919, (b) shows LSCF1928, (c) shows LSCF1955, and (d) shows oxygen conversion of LSCF1991. As shown in (b), LSCF1928 shows oxygen conversion rate of about 100% at about 450 ° C (oxygen is burned), whereas LSCF1991 does not burn oxygen at 600 ° C Able to know.

From the above, it can be confirmed that LSCF1928 has the maximum oxygen conversion rate.

Hereinafter, the results of the methane oxidation experiment according to the amount of the LSCF1928 powder having the maximum oxygen conversion rate as described above will be described with reference to FIG. 8 through FIG.

Figure 8 according to one embodiment of the present invention, La _0.1 Sr _0.9 Co _0.2 Fe _0.8 to 4g When using a diagram showing the results of the methane oxidation experiment, Figure 9 according to one embodiment of the present invention, La _0.1 Sr _0.9 2 shows the results of a methane oxidation experiment when 1 g of Co _0.2 Fe _0.8 is used. The simulated gas with the same composition ratio as the landfill gas was used. 8 is a graph showing the detection amount of 4 g of LSCF1928 powder in a simulated gas atmosphere.

As shown in FIG. 8, in almost all the temperature ranges, nitrogen hardly changes and agrees with the supplied value. But there was a change in the rest of the gases, including oxygen. Oxygen and methane showed a tendency to decrease with increasing temperature above 350 ℃, and oxygen conversion rate reached to 100% at 425 ℃. FIG. 9 shows the result of observing changes in the gas detection amount at each temperature region after filling 1g of LSCF1928 powder in a simulated gas atmosphere. It was confirmed that the combustion started at 400 ℃ or higher and the oxygen conversion rate reached 100% at 450 ℃ in the simulated gas having almost the same composition as the landfill gas. As a result, it was confirmed that the combustion occurred at a much lower temperature when the LSCF1928 powder reacted as a catalyst.

On the other hand, the perovskite metal oxide according to the present invention can have a more excellent effect through the impregnation. The supporting method can be roughly divided into physical adsorption method and chemical bonding method. The supporting method using physical adsorption is a method which has already been widely applied in the production of a general supported catalyst. A simple method for preparing a supported catalyst by contacting a solution in which a perovskite oxide is dissolved, followed by drying and firing, is applied to the support of a perovskite catalyst since it is easy to apply and economical. Alumina is widely used in various industrial fields because of its excellent chemical stability, high mechanical strength, physical properties such as melting point and hardness. In particular, highly porous alumina is widely used industrially, for example, as a catalyst carrier, an adsorbent, and the range of required physical properties such as pore volume, pore size, pore distribution, and specific surface area varies depending on the purpose of use. Recently, the demand for high porosity alumina having a large pore volume is increasing in accordance with various industrial trends. Alumina can produce crystalline alumina such as gibbsite, bayerite, boehmite, or amorphous alumina according to its preparation method. However, in this study, gamma alumina (γ-Alumina) was used instead of boehmite to avoid generation of impurities due to reaction of alumina and metal oxide after firing.

When such a gamma alumina is used, the catalyst has a surface area and a mechanical strength and has thermal stability.

In addition to the alumina-supporting method, there is a method for producing pellets by a catalyst forming method. Extrusion, injection molding, syringe extrusion and the like are available for producing pellets.

Hereinafter, a method for removing oxygen contained in a methane mixture gas using the oxygen removal catalyst having the above-described structure will be described.

10 is a flowchart for explaining a method for removing oxygen in a methane mixture gas using an oxygen scavenger catalyst according to an embodiment of the present invention. As shown in FIG. 10, in the reaction vessel, La _1-x Sr _x Co _{1 -y} Fe _y O _3-δ wherein x is 0 ≤ x ≤ 1, y is 0 ≤ y ≤ 1 and δ is 0 ≤ lt; 8 < 2) (S1). Here, the reaction tank may be a reaction tank in the oxygen removal device shown in FIG. Then, the reaction tank is heated (S3). That is, as described above, as the perovskite catalyst is heated to 300 to 450 ° C while collecting oxygen in the methane mixture gas, a complete combustion reaction of methane and oxygen occurs in the catalyst. That is, when methane gas is introduced into the reaction tank while the reaction tank is heated, oxygen in the methane mixture gas is removed as methane in the methane mixture gas is completely burned with the oxygen trapped in the perovskite catalyst (S5). That is, the oxygen is removed by the reaction shown in the following [Equation 1].

[Formula 1]

CH ₄ + ₂ O ₂ --CO ₂ + 2H ₂ O

That is, 2 moles of oxygen is removed using 1 mole of methane. As described above with reference to FIG. 2, the methane mixed gas contains less than 2% oxygen and at least 35% methane. Since the reaction of the above formula is generated in the perovskite catalyst in such a methane gas mixture, a trace amount of oxygen can be removed without significantly affecting the methane composition ratio, and a methane mixture gas Thereby removing oxygen in the exhaust gas. In other words, when the perovskite oxygen scavenging catalyst according to the present invention is used, the complete combustion reaction of methane gas and oxygen can be promoted at a middle low temperature of 300 to 600 ° C., so that a small amount of oxygen such as landfill gas It is possible to rapidly remove only oxygen from the methane gas mixture and reduce the risk of industrial accidents due to oxygen during the operation of the landfill gas refining apparatus.

As described above, the method for removing oxygen from the methane mixed gas using the oxygen scavenging catalyst, the perovskite oxygen scavenging catalyst used therein, and the landfill gas methane direct conversion technology using the same, It is to be understood that the present invention is not limited to the above-described embodiments, and all or some of the embodiments may be selectively combined so that various modifications may be made.

100: Landfill gas collecting device
200: Ammonia and hydrogen sulfide removal device
300: Water and dust removal device
400: Inflation adsorption eliminator
500: Oxygen removal device
600: nitrogen removal device
700: DME plant
800: Storage tank
900: Car carrier

Claims (20)

In the reaction vessel, La _1-x Sr _x Co _{1 -y} Fe _y O _3-δ (where x is 0.7 ≦ x ≦ 0.9, y is 0 ≦ y ≦ 1, and δ is a range of 0 ≦ δ <2) Providing a perovskite catalyst;
Heating the reaction vessel;
Wherein when the methane gas mixture is introduced into the reaction vessel while the reaction vessel is heated, oxygen in the methane mixture gas is trapped, and the methane mixture gas contains 0.1 to 2.0% oxygen and 35 to 60% Includes; And
The oxygen captured by the perovskite catalyst in the reaction tank and methane in the methane mixture gas are completely burned only in the perovskite catalyst so that oxygen is captured in the methane mixture gas, And removing the oxygen in the methane mixture gas so that the oxygen content is 0.1% or less.
The method according to claim 1,
The perovskite catalyst,
A method for removing oxygen from a methane mixed gas using an oxygen scavenging catalyst, the method comprising one of powder, pellet, and bead.
The method according to claim 1,
The perovskite catalyst,
Contacting a solution of La _1-x Sr _x Co _1-y Fe _y O _{3 -δ} with gamma-alumina, followed by drying and firing.
The method according to claim 1,
The step of heating the reaction tank comprises:
And heating the perovskite catalyst at 300 to 600 ° C.
The method according to claim 1,
Wherein the perovskite catalyst is produced by one of a high temperature firing method, a citric acid method and a complex polymerization method.
delete delete The method according to claim 1,
wherein x = 0.9 and y = 0.8.
The method according to claim 1,
wherein x = 0.9 and y = 0.5.
The method according to claim 1,
wherein x = 0.9 and y = 0.9.
The method according to claim 1,
wherein x = 0.9 and y = 0.1.
delete delete delete delete delete delete A landfill gas collecting device installed in the landfill to collect landfill gas containing 0.1 to 2% of oxygen and 35 to 60% of methane;
An ammonia and hydrogen sulfide removal device for removing ammonia and hydrogen sulfide from the captured landfill gas;
A water and dust removing device for removing moisture and fine dust from the first purification buried gas firstly purified by the ammonia and hydrogen sulfide removing device;
An apparatus for removing siloxane from a second purified landfill gas which is secondarily purified by the water and dust removing apparatus;
In the third purification buried gas which has been thirdly purified by the inhalation desorption removing apparatus, La _1-x Sr _x Co _{1 -y} Fe _y O _3-δ wherein x is 0.7 ≦ x ≦ 0.9, y is 0 ≤ y ≤ 1 and δ is in the range of 0 ≤ δ <2);
A nitrogen removal device for removing nitrogen from the fourth purification buried gas which is quadratically purified by the oxygen removal device; And
And a storage tank for storing a fifth purification buried gas that is fifthly purified by the nitrogen removal device,
The oxygen-
The perovskite catalyst is heated to 300 to 600 ° C. so that only the complete combustion reaction of methane and oxygen in the third purified landfill gas is performed to remove oxygen in the third purified landfill gas so that the oxygen content is 0.1% To the landfill gas purification system.
delete 19. The method of claim 18,
x = 0.9, y = 0.8, and a landfill gas purification system using direct methane conversion technology.

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