Manganese-based adsorbent for desulfurization, and manufacturing method thereof

Abstract

To provide: an adsorbent for desulfurization in which a composite oxide comprising manganese, copper and potassium is supported on an alumina or zeolite carrier; a method for manufacturing the same; and a method for adsorbing organic sulfur at room temperature by using the same.SOLUTION: In a manganese-based adsorbent for desulfurization, a potassium-manganese-copper composite oxide is supported on a carrier having an acidic point. The carrier is proton-form zeolite, pseudo-boehmite, or a mixture of proton-form zeolite and pseudo-boehmite. The content of the potassium-manganese-copper composite oxide is such that the potassium content is 1-3 wt.%, the manganese content is 60-85 wt.%, and the copper content is 5-15 wt.%, based on the total weight of the adsorbent.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a manganese-based adsorbent for desulfurization, and more specifically, to a manganese-based adsorbent having a structure in which a composite oxide made of manganese, copper, and potassium is supported on an alumina or zeolite carrier, and in which changes in electrical characteristics have been confirmed according to the interaction between the carrier and the manganese-copper-potassium composite oxide. The present invention relates to a manganese-based adsorbent for adsorption desulfurization that has an excellent effect of removing sulfur compounds such as tertiary butyl mercaptan (TBM) at room temperature even when it contains small amounts of manganese and copper. [Background technology]

[0002] A fuel cell is a power generation system that converts the chemical energy of hydrogen and oxygen contained in hydrocarbon substances such as methanol, ethanol, and natural gas into electrical energy. In the fuel processing device of a fuel cell, a catalyst is used to reform the hydrocarbon fuel gas to generate hydrogen, but since hydrocarbons usually contain sulfur compounds, which are poisonous substances, it is necessary to remove the sulfur compounds before reforming. In particular, city gas used as the supply fuel for fuel cells contains TBM (tertiary butyl mercaptan), a sulfur compound that acts as an odorant, so it is essential to remove the sulfur compounds before using it in a fuel cell. Summary of the Invention [Problem to be solved by the invention]

[0003] Although various adsorbents exist for removing sulfur compounds such as TBM from fuel gases, there is still a demand for adsorbents with high adsorption properties at room temperature.

[0004] A first object of the present invention is to provide a manganese-based adsorbent for desulfurization that can efficiently remove sulfur compounds with small amounts of active metals, that is, manganese and copper.

[0005] A second object of the present invention is to provide a method for producing a manganese-based adsorbent for desulfurization.

[0006] A final object of the present invention is to provide a desulfurization method for removing sulfur compounds using a manganese-based desulfurization adsorbent. [Means for solving the problem]

[0007] In order to achieve the above technical objectives, the present invention provides a manganese-based adsorbent for adsorptive desulfurization, in which a manganese-copper-potassium composite oxide is supported on a carrier having acid sites.

[0008] Preferably, the support comprises a zeolite or an alumina, more preferably proton form zeolite Y (HY-Zeolite) or pseudo-boehmite alumina. Effect of the Invention

[0009] According to the present invention, zeolite Y or pseudoboehmite alumina exhibits adsorption properties not observed in clay or crystalline alumina, since it interacts with the composite oxide through a unique chemical bond. The content of the carrier is 10-25 wt% based on the total weight of the adsorbent. In addition to improving the dispersibility of the supported composite oxide, the carrier changes the electrical properties of the composite oxide to increase the adsorption strength for sulfur compounds and improve the adsorption performance. Without being limited by theory, it is understood that as electrons are transferred from the composite oxide to the carrier due to the influence of the carrier, the adsorption strength of electron-deficient manganese and copper metals for sulfur compounds is enhanced. [Brief description of the drawings]

[0010] [Figure 1] 1 is a graph showing the results of room temperature adsorption of TBM (tert-butyl mercaptan) by adsorbents according to examples and comparative examples of the present invention. [Diagram 2]1 is a graph showing the results of UV-visible spectroscopy analysis of adsorbents according to examples and comparative examples of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] As used herein, the term "supported" refers to the phenomenon in which an active metal is deposited, impregnated, or incorporated onto the surface of a support or within the pores of the support, and may be used interchangeably with the term coated.

[0012] The metal oxides supported on the carrier are potassium oxide, manganese oxide and copper oxide, and in this specification, manganese oxide and copper oxide are also called active metals. The metal oxides can be impregnated into the carrier in sequence, and the order of impregnation does not determine the adsorption performance, but it is preferable to impregnate the carrier with the potassium precursor, and the manganese and copper precursors in that order. The metal oxides are supported on the carrier by an oxidation-reduction reaction. A potassium precursor solution is used as an oxidizing agent, and manganese and copper precursor solutions are applied as reducing agents. The adsorbent produced by the oxidation-reduction method has better adsorption performance than adsorbents formed by other manufacturing methods such as solid phase precipitation. The content of the metal oxide is 1 to 3 wt% for potassium oxide, 60 to 85 wt% for manganese oxide, and 5 to 15 wt% for copper oxide, based on the total weight of the adsorbent.

[0013] In order to achieve the second technical object of the present invention, a) preparing a mixture of a potassium precursor solution and a support; b) preparing a copper and manganese precursor solution; c) introducing a copper and manganese precursor solution into the carrier mixture and aging the mixture to produce the adsorbent.

[0014] The carrier for improving the dispersibility of active metals and improving the adsorption to sulfur compounds by changing the electrical properties includes zeolite or alumina. The potassium precursor can be potassium permanganate as an oxidizing agent, and the copper and manganese precursors can be realized in various forms such as nitrates, sulfates, acetates, etc., and are used as reducing agents. The precursors form a composite oxide on the carrier according to an oxidation-reduction reaction. According to the present invention, for optimal oxidation-reduction reaction, the reaction temperature in the a), b) and c) steps is preferably 40-120°C, the stirring speed is 60-500 rpm, and the feeding speed in the c) step is 0.5-5 mL / min, and the aging time is 2-50 hours, so that the oxidation-reduction reaction is carried out to form an optimal composite oxide.

[0015] After the step c), the method may further include a step of selectively obtaining the adsorbent through a filtration process, and a step of drying the obtained material to obtain the final product.

[0016] To achieve the last technical objective, the present invention provides a desulfurization method for removing sulfur compounds by passing a fuel gas through a manganese-based desulfurization adsorbent.

[0017] The method of desulfurization using a manganese-based adsorbent is to pass a fuel gas containing sulfur compounds through the manganese-based adsorbent of the present invention. Representative sulfur compounds include, but are not limited to, thiophenes, mercaptans, and disulfides. The temperature range suitable for desulfurization using a manganese-based adsorbent is 15 to 50°C. As the ambient temperature increases, the adsorption performance of the adsorbent decreases, so it is preferable to use the adsorbent at 30°C or less.

[0018] Hereinafter, the configuration and effects of the present invention will be described in more detail using specific examples and comparative examples. However, these examples are merely for the purpose of making the present invention more clearly understandable and are not intended to limit the scope of the present invention.

[0019] <Example 1> 6.14 g of copper nitrate trihydrate and 23.7 g of manganese acetate tetrahydrate were dissolved in 67 mL of deionized water to prepare a mixed aqueous solution of copper nitrate and manganese acetate (aqueous solution A). Separately, 12.7 g of potassium permanganate was dissolved in 67 mL of deionized water, and then 3.4 g of pseudoboehmite alumina, which had been previously dehydrated at 120 ° C, was mixed to prepare an aqueous solution (aqueous solution B). Aqueous solution A was added to aqueous solution B at a rate of 3 mL / min while stirring aqueous solution B at 60 ° C, and stirring was continued for another 6 hours to generate and mature a precipitate. The precipitate was then filtered, washed with deionized water, and then collected and dried at 120 ° C overnight. The dried precipitate was pulverized to obtain adsorbent 1.

[0020] <Example 2> 6.14g of copper nitrate trihydrate and 23.7g of manganese acetate tetrahydrate were dissolved in 67mL of deionized water to prepare a mixed aqueous solution of copper nitrate and manganese acetate (aqueous solution A). Separately, 12.7g of potassium permanganate was dissolved in 67mL of deionized water, and then 3.4g of hydrogen form Y zeolite (SiO2 / Al2O3=5) that had been previously dehydrated at 120°C was mixed to prepare an aqueous solution (aqueous solution B). Aqueous solution A was added to aqueous solution B at a rate of 3mL / min while stirring aqueous solution B at 60°C, and stirring was continued for another 6 hours to generate and mature a precipitate. The precipitate was then filtered, washed with deionized water, and then collected and dried at 120°C overnight. The dried precipitate was pulverized to obtain adsorbent 2.

[0021] In order to confirm the effect of the presence or absence of a carrier on the adsorption performance, Comparative Example 1 was carried out.

[0022] <Comparative Example 1> 6.14 g of copper nitrate trihydrate and 23.7 g of manganese acetate tetrahydrate were dissolved in 67 mL of deionized water to prepare a mixed aqueous solution of copper nitrate and manganese acetate (aqueous solution A). Separately, 12.7 g of potassium permanganate was dissolved in 67 mL of deionized water to prepare an aqueous solution (aqueous solution B). Aqueous solution A was added to aqueous solution B at a rate of 3 mL / min while stirring aqueous solution B at 60°C, and stirring was continued for another 6 hours to generate and mature a precipitate. The precipitate was then filtered, washed with deionized water, collected, and dried overnight at 120°C. The dried precipitate was pulverized to obtain adsorbent 3.

[0023] In order to confirm the effect of the adsorption performance depending on the presence or absence of chemical bonds between the composite oxide and the carrier, Comparative Examples 2 and 3 were carried out.

[0024] <Comparative Example 2> Adsorbent 3 produced in Comparative Example 1 was physically mixed with 3.4 g of pseudoboehmite alumina from which moisture had been removed at 120° C. in advance to obtain adsorbent 4.

[0025] <Comparative Example 3> Adsorbent 3 prepared in Comparative Example 1 was physically mixed with 3.4 g of hydrogen form Y zeolite, which had been previously dehydrated at 120° C., to obtain adsorbent 5.

[0026] Finally, in order to confirm the effect of the manufacturing method on the adsorption performance, Comparative Examples 4 and 5 were carried out using the solid phase precipitation method instead of the oxidation-reduction reaction.

[0027] <Comparative Example 4> A mixture was prepared by grinding and mixing 6.14g of copper nitrate trihydrate, 43.7g of manganese acetate tetrahydrate, and 3.4g of pseudoboehmite alumina, which had been previously dehydrated at 120°C. 33.8g of sodium bicarbonate was added to the mixture, which was then ground and mixed to produce a uniform mixture, after which 18.5g of deionized water was added to cause precipitation. After the addition of deionized water, the mixture was ground and mixed until no more bubbles were generated to produce a precipitate, which was then aged. The precipitate was washed with deionized water, collected, and dried at 120°C overnight. The dried precipitate was ground to obtain adsorbent 6.

[0028] <Comparative Example 5> 6.14g of copper nitrate trihydrate, 43.7g of manganese acetate tetrahydrate, and 3.4g of hydrogen form Y zeolite, which had been previously dehydrated at 120°C, were crushed and mixed to prepare a mixture. 33.8g of sodium bicarbonate was added to the mixture, which was crushed and mixed to prepare a uniform mixture, and then 18.5g of deionized water was added to cause precipitation. After the addition of deionized water, the mixture was crushed and mixed until no more bubbles were generated to produce a precipitate, which was then aged. The precipitate was washed with deionized water, collected, and dried at 120°C overnight. The dried precipitate was crushed to obtain adsorbent 7.

[0029] Meanwhile, to evaluate the adsorption performance, the adsorbents obtained in the examples and comparative examples were dehydrated at 120°C, weighed out at 0.1 g, and charged into a quartz reaction tube with a diameter of 15 mm. The inside was then switched to a nitrogen atmosphere, and 175 ppm TBM (N2 balance) gas was flowed at 39 sccm to evaluate the adsorption performance. The adsorption performance was evaluated by measuring the time from the moment the TBM was first flowed to the moment the sulfur component was detected using PFPD GC, and the amount of sulfur adsorption was calculated.

[0030] FIG. 1 shows the results of TBM room temperature adsorption of the adsorbents according to the examples and comparative examples of the present invention, and it can be seen that the adsorption amount of adsorbents 1 and 2 is improved compared to adsorbent 3 (Comparative Example 1) that does not contain a carrier. Referring to FIG. 2, the adsorbent of Comparative Example 1 has a band gap energy of about 1.8 eV, but in the cases of Examples 1 and 2 in which an acidic carrier is applied, the band gap energy becomes larger as electrons shift from the complex oxide to the carrier, and it is determined that the adsorption strength increases accordingly. In addition, it is confirmed that the adsorbents of Comparative Examples 2 and 3, which contain a carrier but lack chemical bonds with the complex oxide, have smaller band gap energy than those of Examples 1 and 2, and therefore have lower adsorption performance effects.

[0031] The manganese-based adsorbent for desulfurization of the present invention contains a carrier that changes the electrical state of the active metal compared to conventional desulfurization adsorbents, thereby inducing an electron-deficient state of the active metal, thereby improving the adsorption ability for sulfur compounds. Therefore, even if a small amount of active metal is applied, the manganese-based adsorbent for desulfurization of the present invention has the effect of efficiently removing sulfur compounds from fuel gas at room temperature.

Claims

1. A potassium-manganese-copper composite oxide is supported on a support that has acid sites. A manganese-based adsorbent for desulfurization characterized by the above.

2. The support is hydrogen-formed zeolite, pseudo-boehmite, or a mixture of hydrogen-formed zeolite and pseudo-boehmite. The manganese-based adsorbent for desulfurization according to claim 1.

3. The content of the potassium-manganese-copper composite oxide is 1 to 3 wt % for potassium, 60 to 85 wt % for manganese, and 5 to 15 wt % for copper, based on the total weight of the adsorbent. The manganese-based adsorbent for desulfurization according to claim 1.

4. A method for producing a manganese-based adsorbent for desulfurization, comprising the steps of: a) preparing a mixture of a potassium precursor solution as an oxidant and a support; b) preparing a copper and manganese precursor solution as reducing agents; c) adding copper and manganese precursor solutions to the carrier mixture and aging to produce an adsorbent. A method for producing a manganese-based adsorbent comprising the steps of:

5. A method for removing sulfur compounds by passing a fuel gas through the manganese-based adsorbent for desulfurization according to any one of claims 1 to 3. The desulfurization method according to claim 1,

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