ZEOLITE CATALYST FOR HYDROCARBON OXIDATION AND METHOD FOR MANUFACTURING THE SAME

Abstract

A manufacturing method of a hydrocarbon oxidation catalyst and a catalyst therefrom, including preparing a positive ion type of zeolite, and supporting palladium (Pd) in the positive ion type of zeolite by an ion exchange method to obtain a palladium-supported zeolite, wherein an amount of the supported palladium is 0.5 to 5 wt % based on an entire weight of the hydrocarbon oxidation catalyst.

Claims

1. A hydrocarbon oxidation catalyst comprising: a zeolite catalyst supported with palladium; wherein the palladium is supported at 0.5 to 5 wt % based on the entire weight of the supported zeolite catalyst.

2. The hydrocarbon oxidation catalyst of claim 1, wherein the zeolite has a Si/A1 ratio of 1 to 50.

3. The hydrocarbon oxidation catalyst of claim 1, wherein the zeolite is one or more of a group consisting of: AEI, AFX, ERI, LTA, and CHA zeolites.

4. The hydrocarbon oxidation catalyst of claim 1, wherein the palladium is supported at 1.5 to 2.5 wt % based on the entire weight of the supported zeolite catalyst.

5. The hydrocarbon oxidation catalyst of claim 1, wherein in the hydrocarbon oxidation catalyst, an oxidation capacity performance degradation level is 30% or less when the catalyst is degraded under a condition for 12 hours while flowing air containing 10% water at 100 ml/min to a catalyst layer heated to 850° C. to 950° C.: wherein the performance degradation level is calculated by an equation:
(before deterioration−after deterioration)/(before deterioration)*100%.

6. A manufacturing method of a hydrocarbon oxidation catalyst comprising: preparing a positive ion type of zeolite; and supporting palladium (Pd) in the positive ion type of zeolite by an ion exchange method to obtain a palladium-supported zeolite; wherein an amount of the supported palladium is 0.5 to 5 wt % based on an entire weight of the hydrocarbon oxidation catalyst.

7. The manufacturing method of the hydrocarbon oxidation catalyst of claim 6, wherein the positive ion type of zeolite has a Si/Al ratio of 1 to 50.

8. The manufacturing method of the hydrocarbon oxidation catalyst of claim 6, wherein the positive ion type of zeolite is one or more of a group consisting of: AEI, AFX, ERI, LTA, and CHA positive ion types of zeolites.

9. The manufacturing method of the hydrocarbon oxidation catalyst of claim 6, wherein in the preparing of the positive ion type of zeolite, the positive ion type of zeolite is an NH.sub.4 type of zeolite; and the preparing of the NH.sub.4 type of zeolite includes: preparing a zeolite source material; refluxing the zeolite source material into ammonium; and obtaining an NH.sub.4 type of zeolite including an NH.sub.4.sup.+ ion through washing and drying after the refluxing.

10. The manufacturing method of the hydrocarbon oxidation catalyst of claim 6, wherein in the preparing of the positive ion type of zeolite, the positive ion type of zeolite is an H type of zeolite, and the preparing of the H type of zeolite includes: preparing a zeolite source material; refluxing the zeolite source material into ammonium; obtaining an NH.sub.4 type of zeolite including an NH.sub.4.sup.+ ion through washing and drying after the refluxing; and calcining the obtained NH.sub.4 type of zeolite at 500 to 700° C. for 5 to 10 hours to obtain an H zeolite.

11. The manufacturing method of the hydrocarbon oxidation catalyst of claim 6, wherein the supporting of the palladium (Pd) into the positive ion type of zeolite by an ion exchange method includes: mixing zeolite in the palladium precursor solution; increasing a temperature of the mixed solution to perform ion exchange; washing and drying; calcining; and H.sub.2-treating; wherein the palladium precursor solution is one or more selected from a group including palladium acetate monohydrate, palladium nitride, palladium nitrate, and palladium sulfate.

12. The manufacturing method of the hydrocarbon oxidation catalyst of claim 11, wherein the increasing of the temperature of the mixed solution to perform the ion exchange is performed at a temperature of 25° C. to 80° C. for 1 hour to 24 hours.

13. The manufacturing method of the hydrocarbon oxidation catalyst of claim 11, wherein the washing and drying is performed at a temperature of 50 to 100° C. for 6 to 18 hours.

14. The manufacturing method of the hydrocarbon oxidation catalyst of claim 11, wherein the calcination is performed for 1 to 24 hours at a temperature of 400 to 750° C. in an air atmosphere.

15. The manufacturing method of the hydrocarbon oxidation catalyst of claim 11, wherein the H.sub.2 treatment is performed for 1 hour to 5 hours at a temperature 200 to 500° C. in an H.sub.2 atmosphere.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0028] FIG. 1 is a graph for evaluating a methane oxidation capacity of an experimental example in the present disclosure.

[0029] FIG. 2 is a graph for evaluating an ethane oxidation ability of an experimental example in the present disclosure.

[0030] FIG. 3 is a graph for evaluating a pentane oxidation ability of an experimental example in the present disclosure.

DETAILED DESCRIPTION

[0031] Advantages and features of the technology to be described later, and a method for achieving them, will become apparent with reference to embodiments described later in detail together with accompanying drawings. However, implemented forms may not be limited to the embodiments disclosed below. Although not specifically defined, all terms including technical and scientific terms used herein have meanings understood by ordinary persons skilled in the art. The terms have specific meanings coinciding with related technical references and the present specification as well as lexical meanings. That is, the terms are not construed as having ideal or formal meanings.

[0032] Throughout this specification, unless explicitly described to the contrary, the word “comprise”, and variations such as “comprises” or “comprising”, will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.

[0033] In addition, the terms of a singular form may include plural forms unless referred to the contrary.

[0034] The manufacturing method of a hydrocarbon oxidation catalyst according to an embodiment of the present disclosure includes preparing a positive ion type of zeolite; and supporting palladium (Pd) in the zeolite by an ion exchange method.

[0035] The positive ion type of zeolite may be a NH.sub.4 type or H type of zeolite.

[0036] The preparing of the NH.sub.4 type of zeolite includes preparing a zeolite source material, refluxing the zeolite source material in an ammonium salt, and washing and drying the zeolite source material after the refluxing to obtain an NH.sub.4 type of zeolite containing NH.sub.4.sup.+ ions. At this time, the ammonium salt is not limited as long as it may be dissociated into NH.sub.4.sup.+ ions, and for example, may be an ammonium nitrate (NH.sub.4NO.sub.3). The refluxing may be performed by immersing zeolite in an ammonium aqueous solution and stirring the zeolite for 5 to 7 hours at a temperature of 60 to 100° C.

[0037] The zeolite source material refers to zeolite to which metal positive ions obtained during the zeolite manufacturing process are attached, and may be, for example, Na-zeolite. That is, it is a zeolite that is not substituted with H or NH.sub.4 positive ions.

[0038] The H type of zeolite may be obtained by firing the NH.sub.4 type of zeolite obtained by the above-method at 500 to 700° C. for 5 to 10 hours.

[0039] At this time, the zeolite used to prepare the positive ion type of zeolite may have a Si/Al ratio of 1 to 50. Preferably, the Si/Al ratio may be 5 to 26. More preferably, the Si/Al ratio may be 9 to 15.

[0040] In addition, the used zeolite may be one or more kind of a group consisting of AEI, AFX, EM, LTA, and CHA zeolites. Preferably, it may be one or more in the group consisting of AEI, AFX, and LTA zeolites. More preferably, it may be an AEI zeolite.

[0041] Next, the preparing of the Pd/zeolite catalyst by immersing palladium (Pd) in the positive ion type of zeolite by the ion exchange method is described. Specifically, an ion exchange method in which the positive ion type (H type or NH.sub.4 type) of zeolite is added to a palladium precursor-containing solution to support the palladium metal in the zeolite may be used.

[0042] At this time, the amount of the supported palladium may be 0.5 to 5 wt %, preferably 1.5 to 2.5 wt %, based on the entire weight of the hydrocarbon oxidation catalyst. If the palladium supported amount is too small, such as less than 0.5 wt %, there may be a problem of deteriorated performance of the catalyst due to a decrease in the catalyst active point. If the palladium supported amount is too large, such as more than 5 wt %, there may be a problem that the catalyst performance is deteriorated due to a sintering phenomenon.

[0043] In the palladium ion exchange, the Pd/zeolite may be manufactured by mixing zeolite in the palladium precursor solution such as palladium acetate monohydrate, palladium nitride, palladium nitrate, or palladium sulfate, increasing a temperature of the mixture solution to execute ion exchange; washing and drying, and calcining and H.sub.2 treating. The palladium precursor solution used at this time is preferably palladium nitrate.

[0044] The performing of the ion exchange by increasing the temperature of the mixed solution may be performed for 1 hour to 24 hours at 25° C. to 80° C. depending on the amount of ions to be exchanged. Specifically, it may be performed at 75 to 85° C. for 23 to 25 hours.

[0045] The washing and drying may be carried out for 6 to 18 hours at a temperature of 50 to 100° C. Specifically, it may be washed for 10 to 14 hours at a temperature of 55 to 65° C. and then dried.

[0046] After washing and drying, the calcining is performed. The calcination may be performed for 1 to 24 hours at a temperature of 400 to 750° C. in an air atmosphere. Preferably, the temperature of the calcination may be 500 to 600° C. and the time may be 1 to 3 hours.

[0047] After the calcination, the H2 treatment is performed. The treatment is carried out for 1 to 5 hours at a temperature of 200 to 500° C. in an H2 atmosphere. It is preferably carried out for 1 to 3 hours at a temperature of 350 to 450° C.

[0048] After passing through the H.sub.2 treatment, a zeolite catalyst supported with palladium is obtained.

[0049] Meanwhile, the prepared zeolite catalyst may be hydrothermal-treated for a hydrothermal stability test. The hydrothermal treatment may occur for 12 hours while flowing air containing water at 10% at 100 ml/min to the catalyst layer heated at 850° C. to 950° C.

[0050] The zeolite catalyst according to another embodiment of the present disclosure is manufactured by the above manufacturing method.

[0051] The hydrocarbon oxidation catalyst manufactured by the manufacturing method is a palladium-supported zeolite catalyst, and the palladium is supported at an amount of 0.5 to 5 wt % based on the entire weight of the supported zeolite catalyst. Preferably, the palladium may be supported at an amount of 1.5 to 2.5 wt %.

[0052] The zeolite may have a Si/Al ratio of 1 to 50. Preferably, the Si/Al ratio may be 5 to 26. More preferably, the Si/Al ratio may be 9 to 10.

[0053] The zeolite is one kind or more of the group consisting of AEI, AFX, EM, LTA, and CHA zeolites. Preferably, the zeolite may be one kind or more in the group consisting of AEI, AFX, and LTA zeolites. More preferably, the zeolite may be an AEI zeolite.

[0054] The hydrocarbon oxidation catalyst manufactured by the manufacturing method has excellent hydrocarbon resolution even after the degradation. That is, the hydrocarbon oxidation catalyst has an oxidation capacity performance degradation level of 30% even when the catalyst is degraded under a condition of 12 hours while flowing the air containing 10% water at 100 ml/min to the catalyst layer heated to 850° C. to 950° C. Preferably, the oxidation capacity performance degradation level may be 20% or less. The performance degradation level is calculated by an equation of (before deterioration−after deterioration)/(before deterioration)*100 (%).

[0055] Hereinafter, specific embodiments of the present disclosure are presented. However, the embodiments described below are only intended to specifically illustrate or describe the present disclosure, and this should not limit the scope of the present disclosure.

MANUFACTURING EXAMPLE

Manufacturing of Pd/Zeolite Catalyst

[0056] The Pd/zeolite was manufactured with the composition shown in Table 1 below.

[0057] The H type or NH.sub.4 type of zeolite of each structure in Table 1 was added to a palladium nitrate aqueous solution with a palladium content adjusted to 1-3 wt %, ion-exchanged at 80° C. for 24 hours, and washed and dried. Subsequently, it was calcined in an air atmosphere at 550° C. for 2 hours and treated in an H2 atmosphere at 400° C. for 2 hours to prepare a zeolite (Pd/zeolite) catalyst in which palladium (Pd) was ion-exchanged.

TABLE-US-00001 TABLE 1 Sample Si/Al Pd (wt %) Pd/AEI zeolite 9.7 1.5 Pd/AFX zeolite 6.3 2.4 Pd/ERI zeolite 5.1 2.2 Pd/LTA zeolite 25.3 2.2 Pd/CHA zeolite 11.8 2

EXPERIMENTAL EXAMPLE

Performance Evaluation of Palladium-Supported Zeolite (Pd/Zeolite) Catalyst

[0058] The saturated hydrocarbon oxidation capacity was evaluated by using a zeolite catalyst in which the manufactured palladium is ion-exchanged. The oxidation capacities of the non-deteriorated Pd/zeolite catalyst and the degraded Pd/zeolite catalyst were compared.

[0059] At this time, the degraded catalyst was prepared by hydrothermal treatment (for the deterioration) for 12 hours while flowing air containing 10% water in the prepared Pd/zeolite catalyst at 100 ml/min to the catalyst layer heated to 900° C.

[0060] FIG. 1 to FIG. 3 are graphs comparing results of oxidation performance of a saturated hydrocarbon mixture gas before and after the degradation of the prepared Pd/zeolite catalyst. In other words, they are graphs comparing the amount oxidized in the catalyst before the degradation and the amount oxidized in the catalyst after the degradation for each of methane CH.sub.4, ethane C.sub.2H.sub.6, and pentane C.sub.5H.sub.12 among the injected mixture gas.

[0061] 0.1 g of the Pd/zeolite catalyst was used, the reaction was carried out by injecting the saturated hydrocarbon mixture gas into the pretreated catalyst layer, and a concentration of the gas (unreacted) exhausted to a gas chromatography (GC) device was analyzed. A conversion rate of each saturated hydrocarbon is calculated by an equation ((injected amount−unreacted amount)/injected amount)*100 (%). The reaction was measured by increasing the temperature with an interval of 25° C. starting at 200° C., and the pre-treatment and the reaction conditions are shown in Table 2 below. The gas composition is volume %.

TABLE-US-00002 TABLE 2 Pre-treatment condition Reaction condition Temperature (° C.) 550 200 to 550 Total flow rate (ml/min) 200 200 Space speed (h.sup.−1) 50,000 50,000 HC (%) — 0.2 CO (%) 0.9 0.9 H.sub.2 (%) 0.3 0.3 O.sub.2 (%) 0.6 1.0 H.sub.2O (%) 5 5 N.sub.2 (%) Remainder Remainder

[0062] In Table 2, the space speed is a reciprocal of a contact time between the gas flowing to the catalyst and the catalyst in each condition. Among reaction conditions of Table 2, the temperature conditions are different according to each experiment condition to be described below. The composition of the saturated hydrocarbon mixture gas that may be charged when evaluating the catalyst performance is shown in Table 3 below. Table 3 shows the number of carbons in each hydrocarbon.

TABLE-US-00003 TABLE 3 Content (%) Hydrocarbon C1 reference CH.sub.4:saturated HC 47 C.sub.2H.sub.6:saturated HC 10 C.sub.3H.sub.6:unsaturated HC 33 C.sub.5H.sub.12:saturated HC 10

Experimental Example 1: Evaluation of Oxidation Capacity of Methane CH.SUB.4

[0063] The Pd/zeolite catalyst before the degradation and the degraded Pd/zeolite catalyst, each of which was completed until the pretreatment, were mounted in a catalyst reactor, and a saturated hydrocarbon mixture gas was charged as a reaction product to evaluate the oxidation capacity. The reaction was carried out in the range of 200 to 550° C., and the conversion rates of methane CH.sub.4 measured at 475° C. were compared. Other reaction conditions are shown in Table 2.

[0064] Before and after the deterioration, the methane oxidation capacity of Pd/AEI, Pd/AFX, Pd/ERI, Pd/LTA, and Pd/CHA was evaluated, respectively, and a representative result of 475° C. is shown in FIG. 1 and Table 4.

TABLE-US-00004 TABLE 4 Performance CH.sub.4 conversion ratio (%) degradation Before deterioration After deterioration level (%) Pd/AEI  79 70 11 Pd/AFX  98 25 74 Pd/ERI  89  9 90 Pd/LTA  98 35 64 Pd/CHA 100 22 78

[0065] In Table 4, the performance degradation level is calculated by an equation (before deterioration−after deterioration)/(before deterioration)*100 (%), and the conversion rate in Table 4 refers to the oxidized amount among the charged methane amount. As a result, when comparing only degradation products, Pd/AEI showed the most excellent performance, and the performance was lowered in order of Pd/LTA, Pd/AFX, Pd/CHA, and Pd/ERI. In addition, when comparing the performance degradation level of degradation products compared to new products, the performance degradation in the Pd/AEI catalyst was the lowest, and the performance degradation width was large in the order of Pd/LTA, Pd/AFX, Pd/CHA, and Pd/ERI. That is, it was found that the Pd/AEI zeolite had almost the same level of methane oxidation capacity as before the degradation even after the degradation.

Experimental Example 2: Evaluation of an Oxidation Capacity of Ethane C.SUB.2.H.SUB.6

[0066] The Pd/zeolite catalyst before the degradation and the degraded Pd/zeolite catalyst, each of which was completed until the pretreatment, were mounted in a catalyst reactor, and a saturated hydrocarbon mixture gas was charged as a reaction product to evaluate the oxidation capacity. The reaction was carried out in the range of 200 to 550° C., and the conversion rates of ethane (C.sub.2H.sub.6) measured at 425° C. were compared. Before and after the deterioration, the ethane oxidation capacity of Pd/AEI, Pd/AFX, Pd/ERI, Pd/LTA, and Pd/CHA was evaluated, respectively, and a representative result at 425° C. is shown in FIG. 2 and Table 5.

TABLE-US-00005 TABLE 5 Performance C.sub.2H.sub.6 conversion rate (%) degradation Before deterioration After deterioration level (%) Pd/AEI  81 78  4 Pd/AFX 100 40 60 Pd/ERI  93 17 82 Pd/LTA  99 62 38 Pd/CHA 100 33 67

[0067] In Table 5, the performance degradation level was calculated by an equation (before deterioration−after deterioration)/(before deterioration)*100 (%), and the conversion rate in Table 5 refers to the oxidized amount among the charged ethane amount. As a result, when comparing only the degradation products, Pd/AEI showed the most excellent performance, and the performance decreased in the order of Pd/LTA, Pd/AFX, Pd/CHA, and Pd/ERI. In addition, when comparing the performance degradation level of degradation products compared to new products, the performance degradation in the Pd/AEI catalyst was the lowest, and the performance degradation width was larger in the order of Pd/LTA, Pd/AFX, Pd/CHA, and Pd/ERI. Like the case of methane, it was found that the Pd/AEI zeolite had almost the same level of the ethane oxidation capacity as before the degradation even after the degradation.

Experimental Example 3: Evaluation of Oxidation Capacity of Pentane (C.SUB.5.H.SUB.12.)

[0068] The Pd/zeolite catalyst before the degradation and the degraded Pd/zeolite catalyst, each of which was completed until the pretreatment, were mounted in a catalyst reactor, and a saturated hydrocarbon mixture gas was charged as a reaction product to evaluate the oxidation capacity. The reaction was performed in the range of 200 to 550° C., and the conversion rates of pentane (C5H12) measured at 350° C. were compared. Before and after the deterioration, the oxidation capacities of Pd/AEI, Pd/AFX, Pd/ERI, Pd/LTA, and Pd/CHA were evaluated, respectively, and a representative 350° C. result is shown in FIG. 3 and Table 6.

TABLE-US-00006 TABLE 6 Performance C.sub.5H.sub.12 conversion rate (%) degradation Before deterioration After deterioration level (%) Pd/AEI  88 72 18 Pd/AFX  98 49 50 Pd/ERI  89 28 68 Pd/LTA  92 49 46 Pd/CHA 100 57 43

[0069] In Table 6, the performance degradation level was calculated by an equation (before deterioration−after deterioration)/(before deterioration)*100 (%), and the conversion rate in Table 6 refers to the oxidized amount among the charged pentane amount. As a result, when comparing only the degradation products, Pd/AEI showed the most excellent performance, and the performance decreased in the order of Pd/CHA, Pd/LTA, Pd/AFX, and Pd/ERI. In addition, when comparing the performance degradation level of degradation products compared to new products, the performance degradation in the Pd/AEI catalyst was lowest, and the performance degradation width was larger in the order of Pd/CHA, Pd/LTA, Pd/AFX, and Pd/ERI. As in the case of methane and ethane, it was found that the Pd/AEI zeolite had almost the same level of the pentane oxidation capacity as before the degradation even after the degradation.

[0070] From the experiment results, it was found that the Pd/AEI zeolite catalyst had superior performance differences before and after the degradation compared to other zeolite catalysts.

[0071] While this disclosure has been described in connection with what is presently considered to be practical embodiments, it is to be understood that the disclosure is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.