KR102220202B1 - Dehydroaromatization catalyst and method of manufacturing btx using the same - Google Patents

Abstract

A supported catalyst and a method for producing BTX using the same are provided. The supported catalyst includes a support including silicon and aluminum, and a metal oxide catalyst supported on the support. The BTX manufacturing method includes performing a dehydrogenation aromatication reaction by supplying a reactant gas to a catalyst layer including the supported catalyst.

Description

A dehydrogenation aromatication catalyst and a method of manufacturing BTX using the same {DEHYDROAROMATIZATION CATALYST AND METHOD OF MANUFACTURING BTX USING THE SAME}

The present invention relates to a supported catalyst and a method for producing BTX using the same.

Methane, propane, and methanol are basic alkanes composed of one and three carbons, and methane is currently mostly used only as an energy source due to its low reactivity despite its large reserves and industrial utility value. Recently, as high oil prices continue and crude oil prices continue to rise, research and development to manufacture high value-added compounds using methane, which has price competitiveness, are in progress. As a representative example, BTX (benzene, toluene, and xylene) is one of high value-added compounds that can be produced using methane, and is used as a raw material for chemical products such as synthetic resins and rubber. Conventional BTX manufacturing processes are mostly naphtha reforming-based processes, and as crude oil prices rise, economic feasibility is poor.

In order to solve the above problems, the present invention provides a supported catalyst capable of effectively performing a dehydrogenation aromatication reaction.

The present invention provides a method for producing BTX using the supported catalyst.

Other objects of the present invention will become apparent from the following detailed description and accompanying drawings.

A supported catalyst according to embodiments of the present invention includes a support including silicon and aluminum, and a metal oxide catalyst supported on the support.

The metal oxide catalyst may include gallium oxide.

The carrier may have mesopores.

In the carrier, the molar ratio of silicon to aluminum (Si/Al) may be 5 to 40. Preferably, in the carrier, the molar ratio of silicon to aluminum (Si/Al) may be 10 to 30.

The carrier may be of the HZSM-5 type.

A method of manufacturing BTX according to embodiments of the present invention includes performing a dehydrogenation aromatication reaction by supplying a reactant gas to a catalyst layer including the supported catalyst.

The reactant gas may include one or two or more of methane, propane, and methanol. The reactant gas may include methane, propane, and methanol. The reactant gas may further include nitrogen.

According to embodiments of the present invention, BTX (benzene, toluene and xylene) can be prepared from methane, propane and/or methanol. It is a different process from the reforming process through naphtha cracking, which is the existing process, and is economical because BTX is directly produced using methane, which is price-competitive, and escapes from dependence on crude oil. The supported catalyst according to the embodiments of the present invention may have a high BTX yield and reaction stability by improving structural characteristics and acid characteristics of the catalyst.

1 shows the results of X-ray diffraction analysis of a supported catalyst according to embodiments of the present invention.
2 shows the results of nitrogen adsorption and desorption experiments of the supported catalyst according to embodiments of the present invention.
3 shows an experiment curve of an elevated temperature ammonia adsorption and desorption of a supported catalyst according to embodiments of the present invention.
Figure 4 shows the conversion rate of reactants when using the supported catalyst GaOy / meso-20HZSM-5 according to an embodiment of the present invention.
5 shows the yield of the product when using the GaOy/meso-20HZSM-5 supported catalyst according to an embodiment of the present invention.
6 shows the conversion rate of the reactant and the yield of the product according to the molar ratio of Si/Al of the supported catalyst according to embodiments of the present invention.

Hereinafter, the present invention will be described in detail through examples. Objects, features, and advantages of the present invention will be easily understood through the following embodiments. The present invention is not limited to the embodiments described herein and may be embodied in other forms. The embodiments introduced herein are provided so that the disclosed content may be thorough and complete, and the spirit of the present invention may be sufficiently transmitted to those of ordinary skill in the art to which the present invention pertains. Therefore, the present invention should not be limited by the following examples.

A supported catalyst according to embodiments of the present invention includes a support including silicon and aluminum and a metal oxide catalyst supported on the support.

The metal oxide catalyst may include gallium oxide.

The carrier may have mesopores.

In the carrier, the molar ratio of silicon to aluminum (Si/Al) may be 5 to 40. Preferably, in the carrier, the molar ratio of silicon to aluminum (Si/Al) may be 10 to 30.

The carrier may be of the HZSM-5 type.

A method of manufacturing BTX according to embodiments of the present invention includes performing a dehydrogenation aromatication reaction by supplying a reactant gas to a catalyst layer including the supported catalyst.

The reactant gas may include one or two or more of methane, propane, and methanol. The reactant gas may include methane, propane, and methanol. By including the methanol, the yield of xylene may increase. The reactant gas may further include nitrogen.

Carrier Manufacturing example

A precursor solution by dissolving 1.30 g of sodium hydroxide, 1.36 g of tetrapropylammonium bromide, 38.2 ml of tetraethyl orthosilicate, and sodium aluminate (a content corresponding to a Si/Al molar ratio of 20, 30, 40) in 108 ml of distilled water Made. The precursor solution was stirred at 40° C. for 3 hours, and then BP-2000 (Cabot Corp.), a carbon template material, was added to the precursor solution so as to be 1% by weight, and stirred at 40° C. for 3 hours. The mixture was injected into a batch reactor and stirred at 160° C. for 72 hours to perform a hydrothermal synthesis process. NaZSM-5 was crystallized and formed by the hydrothermal synthesis process.

A washing process using 1000 ml of distilled water and a drying process at 110° C. for 8 hours were performed, and the temperature was raised to 5° C. per minute in an air atmosphere, and a sintering process was performed at a temperature of 550° C. for 10 hours to burn the carbon template material. Dissolve 8.01 g of ammonium nitrate in 100 ml of distilled water to make an ion exchange solution, and after injecting the calcined resultant to ion exchange for 6 hours at a temperature of 120° C., washing process using 1000 ml of distilled water and drying at 110° C. for 8 hours Through the process, NH4ZSM-5 was prepared. The ion exchange process was performed a total of three times.

NH4ZSM-5 was heated to 5°C per minute and then subjected to a firing process held at 550°C for 5 hours to finally prepare a mesoporous HZSM-5 carrier. In the present specification, the meso-porous HZSM-5 carrier was described as meso-XHZSM-5 (X = molar ratio of Si/Al). For example, when the molar ratio of Si/Al of the carrier is 20, the carrier is expressed as meso-20HZSM-5.

The mesoporous HZSM-5 carrier is advantageous in terms of mass transfer due to the formation of mesopores, as well as shape selectivity that can obtain high BTX selectivity, and can improve reaction activity. In addition, when the Si/Al molar ratio constituting the structure of the mesoporous HZSM-5 carrier is adjusted, the structural properties of the catalyst change, and Bronsted-Lowry acid (B acid) and Lewis acid (L acid) The acid properties of such catalysts also change. Through this, a catalyst having the most optimized structure and acid characteristics can be implemented, thereby increasing reaction efficiency.

Supported catalyst Manufacturing example

A catalyst in which gallium oxide (2% by weight) was supported on meso-XHZSM-5 (X=Si/Al molar ratio, 20, 30, 40), respectively, was prepared using a wet impregnation method. A gallium oxide precursor solution was prepared by adding 0.079 g of a gallium nitrate precursor to 10 ml of distilled water, and the gallium oxide precursor by 1 g of the meso-XHZSM-5 (X=Si/Al molar ratio, 20, 30, 40) carrier After adding to the solution, the mixture was stirred at 85° C. at 300 rotations per minute until the moisture was completely evaporated. After drying at 100° C. for 8 hours, the temperature was raised to 500° C. at a rate of 5° C. per minute, maintained for 4 hours, and fired to prepare a supported catalyst. In the present specification, the supported catalyst on which the gallium oxide is supported was described as GaOy/meso-XHZSM-5 (X=Si/Al molar ratio, 20, 30, 40). For example, when the molar ratio of Si/Al of the support is 20, the supported catalyst is expressed as CaOy/meso-20HZSM-5.

1 shows the results of X-ray diffraction analysis of a supported catalyst according to embodiments of the present invention.

Referring to FIG. 1, the supported catalysts GaOy/meso-20HZSM-5, GaOy/meso-30HZSM-5, and GaOy/meso-40HZSM-5 all showed characteristic peaks of the HZSM-5 crystal phase, which are all prepared It indicates that the supported catalyst is well forming HZSM-5 crystals. In addition, it was analyzed that as the molar ratio of Si/Al increased, the relative sensitivity increased and the crystallinity increased. The peak of gallium oxide did not appear, indicating that gallium oxide was highly dispersed in the meso-XHZSM-5 support in all supported catalysts.

2 shows the results of nitrogen adsorption and desorption experiments of the supported catalyst according to embodiments of the present invention.

Referring to FIG. 2, the supported catalysts GaOy/meso-20HZSM-5, GaOy/meso-30HZSM-5, and GaOy/meso-40HZSM-5 all exhibit IV-type nitrogen adsorption and desorption isotherms. It shows characteristics, and shows the H4-type hysteresis loop under the influence of the carbon template material added to form mesopores. As the Si/Al molar ratio increased, the hysteresis phenomenon was large, and the degree of development of the mesopores increased.

Table 1 summarizes the structural characteristics of the supported catalyst GaOy/XHZSM-5 (X=Si/Al molar ratio, 20, 30, 40). The specific surface area of the supported catalyst prepared from Table 1 is about 356 ~ 399m ² /g, the micropore volume is 0.170 ~ 0.195cm ³ /g, the mesopore volume is about 0.121 ~ 0.153cm ³ /g. This indicates that mesopores are formed when the carbon template material is introduced. Structural properties do not change significantly depending on the Si/Al molar ratio, but as the molar ratio of Al to Si increased, the volume of micropores and the volume of mesopores increased.

[Table 1]

3 shows an experiment curve of an elevated temperature ammonia adsorption and desorption of a supported catalyst according to embodiments of the present invention.

Referring to FIG. 3, the green line of each line represents the total ammonia desorption curve, the red line represents ammonia adsorbed to the weak acid point of the total ammonia desorption amount, the blue line represents ammonia adsorbed to the intermediate acid point, and the pink line It is a desorption curve of ammonia adsorbed to a strong acid point. A weak acid point means a weak Lewis acid, a medium acid point means a strong Lewis acid, and a strong acid point means Bronsted-Lowry acid. Acid points that have a direct effect on the reaction are strong Lewis acid (medium acid point) and Bronsted-Lowry acid (strong acid point), and when the two acid points are maintained at an appropriate ratio, the reaction efficiency can be maximized.

Table 2 shows the results of an elevated temperature ammonia adsorption and desorption experiment of the GaOy/XHZSM-5 supported catalyst (X = Si/Al molar ratio), and shows values for the acid amount of each acid point corresponding to the bar shown in FIG. As the Si/Al molar ratio of the supported catalyst increases, the total amount of acid decreases. In particular, the strong Lewis acid corresponding to the intermediate acid point has a larger decrease than the Bronsted-Lowry acid corresponding to the strong acid point. The strong acid/intermediate acid point ratios of the GaOy/XHZSM-5 supported catalyst (X = Si/Al molar ratio, 20, 30, 40) are 1.04, 1.16, and 1.29, respectively.

[Table 2]

GaOy / meso - 20HZSM -5 BTX Preparation Example 1 by the dehydroaromatic reaction of methane and propane or methane, propane and methanol on a supported catalyst

A reaction for preparing BTX was carried out by dehydrogenation of methane and propane or methane, propane and methanol at a reaction temperature of 550° C. using a GaOy/meso-20HZSM-5 supported catalyst.

The ratio of the gas used in this preparation example was composed of methane: nitrogen: propane = 5:7.5:0.5 or methane: nitrogen: propane: methanol = 5:7.5:0.5:1 by different types and compositions of the reactants. The injection amount of the reactant was set as the total space velocity (GHSV: Gas Hourly Space Velocity) of methane, propane and nitrogen 3900 ml/g-catalyst h or the total space velocity of methane, propane, nitrogen and methanol 4200 ml/g-catalyst h . Prior to the dehydrogenation aromatization reaction, 0.2 g of the catalyst was charged into a quartz reactor, and then the temperature was raised at a rate of 5°C/min to the reaction temperature under a nitrogen atmosphere. By passing through, a dehydrogenation aromatization reaction was performed. In this example, the conversion and yield of the reactants were calculated by the following equations 1, 2 and 3, respectively.

(Equation 1)

(Equation 2)

(Equation 3)

Figure 4 shows the conversion rate of reactants when using the supported catalyst GaOy / meso-20HZSM-5 according to an embodiment of the present invention.

Referring to FIG. 4, the conversion rate of methane and propane in the methane+propane+methanol reaction decreases compared to the methane+propane reaction, and in particular, the methane conversion rate decreases due to the conversion amount from methanol to methane. In addition, the propane conversion rate was also greatly reduced, and the reason for the reduction in methane and propane conversion rates is that 100% converted methanol is involved in not only BTX production but also coke production reaction, thereby deactivating the reaction active point.

5 shows the yield of the product when using the GaOy/meso-20HZSM-5 supported catalyst according to an embodiment of the present invention.

Referring to FIG. 5, the yield of xylene, which is the most valuable among BTX, increases in a methane + propane + methanol reaction. This indicates that the addition of methanol increases the xylene production reaction, and shows an improved xylene yield of 2 to 4% during the reaction time.

GaOy / meso - XHZSM -5 supported On the catalyst Preparation Example 2 of BTX by dehydroaromatic reaction of methane, propane and methanol

Dehydrogenation of methane, propane and methanol was carried out on the GaOy/meso-XHZSM-5 catalyst (X=Si/Al molar ratio, 20, 30, 40). Reaction conditions were carried out in the same manner as in the dehydroaromatic reaction of methane, propane and methanol of Preparation Example 1 of BTX.

6 shows the conversion rate of the reactant and the yield of the product according to the molar ratio of Si/Al of the supported catalyst according to embodiments of the present invention.

6, the conversion rate of methane did not change significantly as the molar ratio of Si/Al was changed, whereas the conversion rate of propane was greatly reduced in the catalyst having a molar ratio of Si/Al of 40, and thus the BTX yield Also, the molar ratio of Si/Al was reduced compared to the catalysts of 20 and 30. In the case of the structural characteristics of the catalyst, as the molar ratio of Si/Al increases, the crystallinity and pore characteristics are improved to show a better reaction activity.However, the BTX yield decreases because the total acid amount, intermediate acid amount, and strong acid amount decrease. Appeared. That is, the structural properties and acid properties tend to be opposite to each other, and thus, the catalyst has high reaction activity in a catalyst having a Si/Al molar ratio of 20 or 30, which is a catalyst in which the two effects are conflicting.

So far, specific examples of the present invention have been described. Those of ordinary skill in the art to which the present invention pertains will be able to understand that the present invention can be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered from an illustrative point of view rather than a limiting point of view. The scope of the present invention is shown in the claims rather than the above description, and all differences within the scope equivalent thereto should be construed as being included in the present invention.

Claims (10)

HZSM-5 type carrier including silicon and aluminum and having medium pores; And
Including gallium oxide supported on the carrier,
As the molar ratio of silicon to aluminum (Si/Al) increases, the volume of the medium pores increases, and the acid amount of strong Lewis acid (medium acid point) and Bronsted-Lowry acid (strong acid point) decrease,
The silicon-to-aluminum molar ratio (Si/Al) ranges from 20 to 30, and in the above range, the dehydrogenation aromatication yield is maximized depending on the volume of the medium pores and the amount of acid. . delete delete delete delete delete A method for producing BTX, comprising the step of performing a dehydrogenation aromatication reaction by supplying a reactant gas to the catalyst layer including the dehydrogenation aromatication catalyst of claim 1. The method of claim 7,
The reactant gas is a method for producing BTX, characterized in that it contains one or two or more of methane, propane, and methanol. The method of claim 8,
The reactant gas is a method for producing BTX, characterized in that it contains methane, propane, and methanol. The method of claim 8,
The reactant gas further comprises nitrogen.

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