KR102234216B1 - Process for Regenerating Zeolite Catalysts for Carbonylation of Dimethyl Ether by Plasma Treatment in a Saturated Steam Flow - Google Patents

Abstract

The present invention relates to a method for regenerating a zeolite catalyst for carbonylation reaction of dimethyl ether. Specifically, the present invention relates to a method for regenerating a zeolite catalyst used to synthesize methyl acetate from a dimethyl ether-containing reactant gas with plasma under saturated steam flow, a catalyst regeneration device used in this method, and a catalyst regenerated through it. And a method for synthesizing methyl acetate using the regeneration catalyst. The method for regenerating a zeolite catalyst for carbonylation reaction of dimethyl ether according to an embodiment of the present invention is to remove coke deposited in the pores of the catalyst by plasma treatment under relatively mild conditions at room temperature and atmospheric pressure, and a saturated steam flow. The structural stability of the product is guaranteed, allowing repeated regeneration and use.

Description

Process for Regenerating Zeolite Catalysts for Carbonylation of Dimethyl Ether by Plasma Treatment in a Saturated Steam Flow}

The present invention relates to a method for regenerating a zeolite catalyst for carbonylation reaction of dimethyl ether. Specifically, the present invention relates to a method for regenerating a zeolite catalyst used to synthesize methyl acetate from a dimethyl ether-containing reactant gas with plasma under saturated steam flow, a catalyst regenerated through it, and a catalyst regeneration device used in this method. And a method for synthesizing methyl acetate using the regeneration catalyst.

A process of selectively producing ethanol (or acetic acid) through catalytic chemical stepwise conversion using C1 gas including hydrogen, carbon monoxide, and carbon dioxide, such as by-product gas, has recently attracted attention. Specifically, dimethyl ether (DME) was synthesized from C1 gas, and methyl acetate (MA) was synthesized by carbonylation of dimethyl ether, and then methyl acetate was hydrogenated. To synthesize ethanol.

The method of synthesizing various alcohols, including ethanol, through a direct catalytic chemical conversion route of conventional by-product gas or synthesis gas, decreases the ethanol yield due to various products and converts from heterogeneous catalysts of expensive precious metal systems such as rhodium (Rh) in particular. Due to the problem showing activity, additional problems such as the cost of the catalyst and ethanol separation appear to occur [J. Catal. 261 (2009) 9-16, Catal. Today 120 (2007) 90-95, Fuel 86 (2007) 1298-1303, etc.].

The production of useful chemicals such as ethanol by direct conversion of the synthesis gas is particularly useful for the high-addition of C1 gas by utilizing C1 gas having various compositions such as shale gas, by-product gas, and biomass-derived synthesis gas. It is being tried as a research. In particular, due to problems such as rapid price fluctuations due to the concentration of petroleum resources, resource protectionism, energy depletion, and environmental pollution, it is useful to utilize various gas resources with a variety of feedstock and relatively abundant supply compared to petroleum resources. Research for the efficient use of C1 gas has been widely attempted through the development of technology for synthesizing value-added chemicals.

This technological trend is in line with the recent increase in the use of bioethanol or ethanol-gasoline mixed fuels. For this reason, it is necessary to develop new technologies that are more efficient and economical than the technology of synthesizing high value-added chemicals such as ethanol using C1 gas conversion via the existing bio route or chemical catalytic conversion of synthetic gases such as by-product gas. The demand for it is increasing.

On the other hand, in order to improve the reaction path of low ethanol yield for synthesizing various alcohols through direct conversion of the synthesis gas, prior studies related to ethanol synthesis including a multi-step reaction process have been reported. In particular, a study on selectively converting dimethyl ether to methyl acetate using a zeolite-based solid acid catalyst [Angew. Chem. Int. Ed. 45 (2006) 1617-1620] or the synthetic route of ethanol via synthesis gas and dimethyl ether or methyl acetate [Ind. Eng. Chem. Res. 49 (2010) 5484-5488] has been reported.

These previous studies have been concentrating on maximizing the yield of dimethyl ether or methyl acetate, which are intermediates of multi-step reactions, by minimizing side reactions in common, which is expected to result in an increase in the yield of the final product, ethanol. In particular, in a previous study on the synthesis of methyl acetate by the carbonylation reaction of dimethyl ether, which is an intermediate reaction in a multi-step reaction, when the catalyst is synthesized by increasing the crystallinity of the catalyst, ferrierite zeolite seeds are used. It has been reported that high catalytic activity and excellent high selectivity of the product methyl acetate can be realized [Catal. Today 303 (2018) 93-99, Catal. Sci. Technol. 8 (2018) 3060-3072].

However, these solid acid-based catalysts are accompanied by coke deposition as a side reaction in the general hydrocarbon production reaction, and carbon deposition on the catalyst surface is reported as a major catalyst deactivation cause of various solid acid catalysts. For long-term use, a catalyst regeneration process is essential.

Specifically, it is known that it is possible to synthesize methyl acetate with a high yield of about 70% or more and a selectivity of 99% or more using a ferrierite catalyst. However, there is a problem in that a hydrocarbon material, that is, coke, generated by a side reaction of the ferrierite catalyst is deposited in the pores of the catalyst, and the activity of the catalyst is rapidly deteriorated. Since the formation of this coke is due to thermodynamic reasons, it is very difficult to completely suppress it.

In general, a technology for regenerating a catalyst deactivated by coke deposition by heat treatment under high temperature oxygen (or air) to remove coke is known.The structure of the catalyst is deformed due to the heat applied during catalyst regeneration, resulting in structural stability of the catalyst. If damaged, the regenerated catalyst may have a lower catalytic activity compared to the original catalyst, and thus it may be difficult to repeatedly use it several times after regeneration.

J. Catal. 261 (2009) 9-16 Catal. Today 120 (2007) 90-95 Fuel 86 (2007) 1298-1303 Angew. Chem. Int. Ed. 45 (2006) 1617-1620 Ind. Eng. Chem. Res. 49 (2010) 5484-5488 Catal. Today 303 (2018) 93-99 Catal. Sci. Technol. 8 (2018) 3060-3072

Accordingly, an object of the present invention is to synthesize methyl acetate by carbonylating dimethyl ether in the presence of a zeolite solid acid catalyst in a multi-stage synthesis of ethanol (or acetic acid) from C1 gas. It is to provide a method of effectively removing coke deposited on the catalyst surface.

Another object of the present invention is to provide a catalyst regenerated through the above method.

Another object of the present invention is to provide a catalyst regeneration apparatus used in the above method.

Another object of the present invention is to provide a method for synthesizing methyl acetate using this regeneration catalyst.

According to an embodiment of the present invention, (1) introducing a zeolite catalyst in which coke is deposited in the pores of the catalyst, which is used for the carbonylation reaction of dimethyl ether in a dielectric barrier discharge type plasma catalyst regeneration apparatus; (2) supplying saturated steam together with air into the plasma catalyst regeneration apparatus; And (3) applying a high voltage to a high voltage electrode in the catalyst regeneration device to generate plasma under a flow of saturated steam to remove 5 to 50% by weight of the total deposited coke. A method for regenerating a catalyst is provided.

According to another embodiment of the present invention, as a zeolite catalyst for the carbonylation reaction of dimethyl ether regenerated by the above method, dimethyl ether conversion and methyl acetate are selected compared to the zeolite catalyst for the carbonylation reaction of unused dimethyl ether. A regenerated zeolite catalyst for the carbonylation reaction of dimethyl ether with a relatively high degree is provided.

According to another embodiment of the present invention, a tubular container made of a dielectric material capable of accommodating a zeolite catalyst used in the carbonylation reaction of dimethyl ether; A ground electrode disposed on the outer wall of the tubular container; A high voltage electrode inserted into the zeolite catalyst accommodated in the tubular container so as to be spatially spaced apart from the tubular container, and applied with a voltage higher than that of the ground electrode; A fixing part for fixing the zeolite catalyst contained in the tubular container to be located in a predetermined area; Saturated steam supply; An air supply unit generating a flow of air to transfer saturated steam into the catalyst regeneration device; And a power supply for providing a regulated voltage to the high voltage electrode, which generates plasma under saturated steam flow by applying a high voltage to the high voltage electrode to remove 5 to 50% by weight of the total coke deposited in the pores of the zeolite catalyst. Used to, a dielectric barrier discharge type plasma catalyst regeneration apparatus is provided.

According to another embodiment of the present invention, (a) synthesizing methyl acetate by carbonylating dimethyl ether in the presence of a zeolite catalyst for carbonylation reaction of dimethyl ether; (b) introducing a zeolite catalyst in which coke is deposited in the pores of the catalyst, which is used for the carbonylation reaction of dimethyl ether into the dielectric barrier discharge type plasma catalyst regeneration apparatus; (c) supplying saturated water vapor together with air into the plasma catalyst regeneration apparatus; And (d) applying a high voltage to a high voltage electrode in the catalyst regeneration device to generate plasma under a flow of saturated steam to remove 5 to 50% by weight of the total immersion coke. And (e) synthesizing methyl acetate by carbonylating dimethyl ether in the presence of a regenerated zeolite catalyst.

The method for regenerating a zeolite catalyst for carbonylation reaction of dimethyl ether according to an embodiment of the present invention can effectively remove coke deposited in the pores of the catalyst by plasma treatment under relatively mild conditions at room temperature and atmospheric pressure, and a flow of saturated steam. , The structural stability of the catalyst is guaranteed, allowing repeated regeneration and use. In addition, by adjusting the reaction rate by remaining without removing a certain amount of coke, inefficient consumption of dimethyl ether and carbon monoxide, which are reactants, and side reactions such as coke deposition reaction can be suppressed. As a result, it is possible to selectively prepare methyl acetate by maintaining a constant carbonylation reaction activity of dimethyl ether for a longer period of time.

1 schematically shows a dielectric barrier discharge type plasma catalyst regeneration apparatus according to an embodiment of the present invention for regeneration of a zeolite catalyst.
FIG. 2 is a diagram showing powder XRD analysis results of regeneration catalysts before and after dimethyl ether reaction.
3 is a diagram showing the results of thermogravimetric analysis (TGA) of catalysts and regeneration catalysts after reaction.
4 is a view showing the results of ammonia desorption analysis of catalysts and regeneration catalysts before and after reaction.

Hereinafter, the present invention will be described in more detail.

According to an embodiment of the present invention, (1) introducing a zeolite catalyst in which coke is deposited in the pores of the catalyst, which is used for the carbonylation reaction of dimethyl ether in a dielectric barrier discharge type plasma catalyst regeneration apparatus; (2) supplying saturated steam together with air into the plasma catalyst regeneration apparatus; And (3) applying a high voltage to a high voltage electrode in the catalyst regeneration device to generate plasma under a flow of saturated steam to remove 5 to 50% by weight of the total deposited coke. A method for regenerating a catalyst is provided.

In the above step (1), a zeolite catalyst in which coke is deposited in the pores of the catalyst, which is used for the carbonylation reaction of dimethyl ether, is introduced into a dielectric barrier discharge type plasma catalyst regeneration apparatus each having a high voltage electrode and a ground electrode on the inside and outside. . Details of the dielectric barrier discharge type plasma catalyst regeneration apparatus will be described later.

Meanwhile, the zeolite catalyst for the carbonylation reaction of dimethyl ether is a kind of solid acid catalyst, such as ferrierite, mordenite, MFI (ZSM-5) zeolite, and honey. A solid acid zeolite catalyst selected from faujasite (FAU) zeolite, Y-zeolite furnace and the like is preferable, but is not particularly limited thereto.

Among the zeolite catalysts used in the carbonylation reaction of dimethyl ether, ferrierite has a two-dimensional structure in which an 8,10-membered ring is connected, and has an average pore size of about 5 Å. It is preferable to have pore characteristics, but is not particularly limited to these pore characteristics.

In the zeolite catalyst used in the carbonylation reaction of dimethyl ether, coke is deposited in the micropores and mesopores, and the activity of the catalyst is reduced.

In the above step (2), saturated water vapor is supplied together with air into the plasma catalyst regeneration apparatus. At this time, the saturated steam may be generated from the constant temperature water bath. The temperature of the saturated steam is 10 ~ 100 ℃, the pressure may be normal pressure, but is not particularly limited to these conditions.

Specifically, the saturated steam generated in the constant temperature water tank may be supplied to the catalyst regeneration device by the flow of air generated by the air supply unit. Here, the air supply unit may include an air storage cylinder, an air mass flow meter, and a gas line, but is not particularly limited to this configuration.

In the above step (3), a high voltage is applied to the high voltage electrode in the catalyst regeneration device to generate plasma under the flow of saturated steam to remove 5-50% by weight of the total immersion coke. Preferably, 10 to 45% by weight, 15 to 45% by weight, 20 to 45% by weight, or 20 to 40% by weight of the total immersion coke may be removed.

In step (3) above, plasma may be generated by dielectric barrier discharge (DBD). "Dielectric barrier discharge" means an electrical discharge between two electrodes separated by an insulating dielectric barrier. In the catalyst regeneration apparatus according to an embodiment of the present invention described later, an alumina tube may be used as a dielectric barrier, but is not particularly limited thereto.

For example, the voltage applied to the high voltage electrode in the catalyst regeneration device in step (3) may be 7 to 50 kV. Preferably, the voltage applied to the high voltage electrode in the catalyst regeneration device may be 15 to 30 kV, but is not particularly limited to this voltage. However, when the applied voltage is less than 7 kV, that is, less than the breakdown voltage, sufficient energy to generate plasma may not be applied to the dielectric and thus plasma may not be generated. Accordingly, the efficiency of removing coke may be significantly lowered. On the other hand, applying a high voltage exceeding 50 kV is physically limited and may result in wasting energy more than necessary.

Step (3) may be performed at a low temperature of 1 to 35°C. For example, step (2) may be performed at a temperature of 10 to 30°C, 10 to 25°C, or 15 to 25°C, but is not particularly limited to this temperature. In the regeneration method according to the embodiment of the present invention, since the catalyst can be regenerated by removing coke at a relatively low temperature, the structure of the catalyst itself is damaged, such as in the case of regeneration by heat treatment under a high-temperature air (or oxygen) flow. It is possible to solve the problems of the prior art, such as a problem of impairing the stability of and a decrease in energy efficiency used for heat treatment at a high temperature.

In addition, step (3) may be performed at normal pressure, but is not particularly limited to this pressure. For example, the pressure for performing step (3) can be selected without limitation to the pressure capable of generating plasma under the applied voltage condition according to Pachen's Law, which indicates the relationship between the applied voltage and the dielectric breakdown voltage. That is, it can be performed by selecting a pressure at a level capable of generating plasma according to the type of dielectric and the voltage applied thereto.

The coke removed by plasma treatment in step (3) may be amorphous carbon or graphitic carbonaceous materials. In this case, the amorphous carbon deposit may be 70% or more based on the total weight of the zeolite catalyst.

In step (3), 5-50% by weight of the total coke deposited in the micropores and mesopores of the zeolite catalyst may be removed. Accordingly, the regenerated zeolite catalyst according to an embodiment of the present invention may include coke remaining in a proportion of 50 to 95% by weight relative to the total coke deposited on the catalyst before regeneration. Preferably, 10 to 45% by weight, 15 to 45% by weight, 20 to 45% by weight, or 20 to 40% by weight of the total immersion coke may be removed. Therefore, according to the embodiment of the present invention, the regenerated zeolite catalyst remains in a ratio of 55 to 90% by weight, 55 to 85% by weight, 55 to 80% by weight, or 60 to 80% by weight of the total coke deposited on the catalyst before regeneration. The coke may be included, but is not particularly limited to this range.

According to another embodiment of the present invention, a zeolite catalyst for the carbonylation reaction of dimethyl ether regenerated by the above method is provided.

The zeolite catalyst regenerated by the method according to the embodiment of the present invention, unlike the catalyst regenerated by the high-temperature heat treatment method, is a fresh zeolite used in the reaction of synthesizing methyl acetate from a reactant gas containing dimethyl ether and carbon monoxide. The crystal structure of the catalyst itself can be stably maintained. That is, even through the regeneration and reaction processes, it is structurally more stable than the heat treatment regeneration catalyst, and further, a certain catalytic activity can be stably maintained for a longer time.

Specifically, the regenerated zeolite catalyst according to an embodiment of the present invention may exhibit a dimethyl ether conversion rate of 1 to 70% during a reaction time of 10 minutes to 2 hours in an activity test. More specifically, the regenerated zeolite catalyst according to an embodiment of the present invention is 3 to 65%, 5 to 60%, 5 to 55%, or 5 to 50% of dimethyl ether during a reaction time of 10 minutes to 2 hours in the activity test. Conversion rate can be indicated.

In addition, the regenerated zeolite catalyst according to an embodiment of the present invention may exhibit a methyl acetate selectivity of 90 to 99% in a carbonylation reaction of dimethyl ether. More specifically, the regenerated zeolite catalyst according to an embodiment of the present invention exhibits a methyl acetate selectivity of 92 to 98%, 93 to 98%, 94 to 98% or 95 to 98% in the carbonylation reaction of dimethyl ether. I can.

According to another embodiment of the present invention, a tubular container made of a dielectric material capable of accommodating a zeolite catalyst used in the carbonylation reaction of dimethyl ether; A ground electrode disposed on the outer wall of the tubular container; A high voltage electrode inserted into the zeolite catalyst accommodated in the tubular container so as to be spatially spaced apart from the tubular container, and applied with a voltage higher than that of the ground electrode; A fixing part for fixing the zeolite catalyst contained in the tubular container to be located in a predetermined area; Saturated steam supply; An air supply unit generating a flow of air to transfer saturated steam into the catalyst regeneration device; And a power supply for providing a regulated voltage to the high voltage electrode, which generates plasma under saturated steam flow by applying a high voltage to the high voltage electrode to remove 5 to 50% by weight of the total coke deposited in the pores of the zeolite catalyst. Used to, a dielectric barrier discharge type plasma catalyst regeneration apparatus is provided.

In the above catalyst regeneration apparatus, as long as the tubular container made of a dielectric material is for conducting dielectric barrier discharge between two electrodes, the material, shape, size, etc. are not particularly limited. For example, in the dielectric barrier discharge type plasma catalyst regeneration apparatus according to an embodiment of the present invention, an alumina tube may be used as a dielectric barrier.

The ground electrode and the high voltage electrode are not particularly limited in material, shape, size, etc., as long as they can be commonly used as electrodes. Preferably, a steel wire and a stainless steel rod may be used as a ground electrode and a high voltage electrode, respectively.

In order to evenly apply plasma to the entire catalyst contained in the tubular vessel, the zeolite catalyst to be regenerated may be supported by a fixing portion and accommodated in a portion covered by a ground electrode in the tubular vessel. Here, the fixing part is a part filled with quartz wool on both sides to fix the position after placing the catalyst in the tubular container.

The saturated steam supply unit may be a constant temperature water bath, but is not particularly limited thereto. The constant temperature water tank is preferably made of a glass material, but is not particularly limited to this material. Specifically, the constant temperature water tank may have a dual structure of an inner container and an outer shell. Here, water is stored in the inner container as a water vapor supply source for supply to the catalyst regeneration device. The outer shell is supplied with circulating water to keep the temperature of the inner container constant. Through this, the temperature of the inner container of the constant temperature water tank can be controlled. The temperature of the saturated steam generated from the constant temperature water bath may be 10 to 100°C, and the pressure may be normal pressure, but is not particularly limited to these conditions.

When the air supplied through the air supply unit passes through the water stored in the container inside the constant temperature water tank, water vapor corresponding to the water vapor pressure according to the temperature of the container inside the constant temperature water tank is generated and transported together with the air into the catalyst regeneration device. Here, the air supply unit may include an air storage cylinder, an air mass flow meter, and a gas line, but is not limited to this configuration.

The power supply unit is not particularly limited as long as it can apply a voltage sufficient to generate plasma by the dielectric barrier discharge. Preferably, a sinusoidal AC power supply (0 to 220 V, 60 to 1,000 Hz) may be connected to a transformer (0 to 20 kV, 1,000 Hz) to be used.

Plasma is generated by applying a high voltage to the high voltage electrode in the catalyst regeneration device to remove 5 to 50% by weight of the total coke deposited in the pores of the zeolite catalyst. The voltage applied to the high voltage electrode is substantially the same as described in the above method for regenerating the zeolite catalyst for the carbonylation reaction of dimethyl ether.

According to another embodiment of the present invention, (a) synthesizing methyl acetate by carbonylating dimethyl ether in the presence of a zeolite catalyst for carbonylation reaction of dimethyl ether; (b) introducing a zeolite catalyst in which coke is deposited in the pores of the catalyst, which is used for the carbonylation reaction of dimethyl ether into the dielectric barrier discharge type plasma catalyst regeneration apparatus; (c) supplying saturated water vapor together with air into the plasma catalyst regeneration apparatus; And (d) applying a high voltage to a high voltage electrode in the catalyst regeneration device to generate plasma under a flow of saturated steam to remove 5 to 50% by weight of the total immersion coke. And (e) synthesizing methyl acetate by carbonylating dimethyl ether in the presence of a regenerated zeolite catalyst.

In the above step (a), methyl acetate is synthesized by carbonylating dimethyl ether in the presence of a zeolite catalyst for carbonylation reaction of dimethyl ether.

Here, the reactant gas may include dimethyl ether and carbon monoxide synthesized through a hydrogenation reaction of the synthesis gas. If necessary, the reactant gas can be mixed with nitrogen. At this time, nitrogen may be mixed in an amount of about 10 times the amount of dimethyl ether to be used, but is not particularly limited to this range. The reactant gas containing dimethyl ether and carbon monoxide may be supplied at a space velocity of 1,000 to 6,000 L/kg-cat/h based on the total flow rate of the reaction gas, but is not particularly limited to this range.

The carbonylation reaction of dimethyl ether is carried out in the presence of a zeolite catalyst. At this time, the content of the zeolite catalyst used is substantially the same as described in connection with the method for regenerating the zeolite catalyst for the carbonylation reaction of dimethyl ether. Preferably, in order to control the heat of reaction of the exothermic reaction, it may be used after physically mixing and diluting with a material such as 1 to 10 times the weight of a diluent such as alpha alumina powder in the form of a powder.

The carbonylation reaction of dimethyl ether may be carried out under, for example, a temperature of 150 to 300°C and a pressure of 5 to 30 bar, but is not particularly limited thereto.

In the above step (b), a zeolite catalyst in which coke is deposited in the pores of the catalyst, which is used for the carbonylation reaction of dimethyl ether, is introduced into a catalyst regeneration apparatus each having a high voltage electrode and a ground electrode inside and outside. Here, the content of step (b) is substantially the same as the content of step (1) of the method for regenerating the zeolite catalyst for carbonylation of dimethyl ether.

In the above step (c), saturated water vapor is fed into the catalyst regeneration apparatus together with airing. Here, the content of step (c) is substantially the same as that of step (2) of the method for regenerating the zeolite catalyst for carbonylation of dimethyl ether.

In the above step (d), a high voltage is applied to the high voltage electrode in the catalyst regeneration device to generate plasma under a flow of saturated steam to remove 5-50% by weight of the total immersion coke. Here, the content of step (d) is substantially the same as the content of step (3) of the method for regenerating the zeolite catalyst for carbonylation of dimethyl ether.

In the above step (e), methyl acetate is synthesized by carbonylating dimethyl ether in the presence of a regenerated zeolite catalyst.

At this time, the carbonylation reaction of dimethyl ether may be carried out under, for example, a temperature of 150 to 300°C and a pressure of 5 to 30 bar, but is not particularly limited to this condition.

In the carbonylation reaction of dimethyl ether in the presence of the regenerated zeolite catalyst of step (e), the conversion of dimethyl ether slightly increases compared to the carbonylation reaction of dimethyl ether with an unused catalyst, Selectivity and yield hardly decrease or increase slightly. In addition, as the reaction time elapses, the reduction in conversion rate due to deactivation of the catalyst tends to be alleviated. From this fact, it can be confirmed that the regenerated catalyst of the present invention was regenerated without substantially altering the structure of the original catalyst. Specifically, the regeneration catalyst of the present invention has a space velocity of about 2,000 L/kg-cat/h, a reaction temperature of 220° C., and a reaction condition of 10 bar reaction pressure, a dimethyl ether conversion of 1 to 40%, and a methyl acetate selectivity of 90 to It may represent 99%, but is not particularly limited to this range.

In addition, since the heat treatment process that impairs the structural stability of the catalyst is not performed, the production of methyl acetate per unit catalyst can be increased by repeating the catalyst regeneration process of step (d) several times.

In the method for producing methyl acetate by the carbonylation reaction of dimethyl ether according to an embodiment of the present invention, steps (d) and (e) may be carried out more than once, but the number of repetitions is particularly limited. It doesn't work.

Example

Hereinafter, the present invention will be described in more detail through examples. These examples are for explaining the present invention more specifically, and the scope of the present invention is not limited by these examples.

Preparation example : Dimethyl Preparation of ether carbonylation catalyst

As a catalyst for the carbonylation reaction of dimethyl ether, a commercial ferrierite zeolite (Vision Chemical, Korea) having a Si/Al ratio of 10 was purchased (FER-Fresh).

For this catalyst, X-ray diffraction (XRD) analysis was performed. Specifically, in a θ/2θ configuration using a Rigaku D/Max-2500V/PC diffractometer (Japan) equipped with Cu Kα radiation (40 kV, 200 mA, λ=0.154 nm) from 5° to 80° XRD analysis was performed. Gas physisorption measurement was performed at 87 K with ASAP 2020 V4.04 (Micromeritics, Inc., USA). Before the measurement, the sample was heat-treated at 623 K for 4 hours under vacuum conditions to remove impurities and degassed. Before the reaction, the gas physisorption isotherm of the catalyst was measured, and the surface area and pore volume were determined.

The powder XRD analysis results and gas physical adsorption results of the ferrierite catalyst before the reaction are shown in FIGS. 2 and 1. Table 1 relates to argon physical adsorption analysis (FER-Fresh).

Catalyst before reaction S _BET
(㎡/g) S _micro
(㎡/g) S _ex
(㎡/g) V _micro (HK)
(Cm 3 /g) V _micro (t-plot)
(Cm 3 /g) FER-Fresh 431.0 372.8 58.21 0.145 0.141

Example 1: under saturated steam flow Plasma Used Dimethyl Regeneration of catalyst for ether carbonylation reaction

DBD plasma regeneration of the ferrierite catalyst used for the carbonylation reaction was performed at atmospheric pressure and room temperature by ventilation using the DBD plasma catalyst regeneration apparatus shown in FIG. 1. The space velocity of air including saturated water vapor supplied to the catalyst regeneration device was 1,500 mL/g-cat/h with the supply of air, and the time for regeneration was about 720 minutes (FER-PS).

In the DBD plasma catalyst regeneration apparatus shown in FIG. 1, an alumina tube having an inner diameter of 6 mm and a thickness of 2 mm was used as a dielectric barrier for the plasma bed. A stainless steel rod of 3 mm diameter was used as a high voltage electrode, and a steel wire was used as a ground electrode. The 150 mm long discharge zone was covered with a ground electrode. The discharge gap between the inner surface of the alumina tube and the high voltage electrode was 1.5 mm, and a commercial ferrierite catalyst was densely filled in the corresponding part after dimethyl ether carbonylation reaction for regeneration. A sinusoidal AC power supply (0~220 V, 60~1,000 Hz) was connected to a transformer (0~20 kV, 1,000 Hz), and a high voltage was continuously applied to the plasma bed as an electrical system. . Specifically, a voltage of 15 kV was applied to the plasma bed, and the frequency was fixed at 1 kHz. A 1 μF capacitance capacitor was connected in series between the plasma bed and ground. Connect a high voltage probe for high voltage electrodes (1,000:1, P6015A, Tektronix) and a voltage probe for ground electrode (10:1, P6100, Tektronix) to a digital oscilloscope (TDS 3012C, Tektronix), respectively. The voltage of was measured. In addition, the saturated steam temperature (that is, the temperature of the constant temperature bath) was 30°C, the saturated steam pressure was 32.824 mmHg, the pressure in the catalyst regeneration device was normal pressure, and the line at the front and rear of the catalyst regeneration device was heated to 70°C.

After plasma regeneration treatment under saturated steam flow, on-line gas chromatography using Porapak-N and molecular sieve 13X columns connected to a thermal conductivity detector (TCD) for effluent gas from the plasma bed. gas chromatograph, 6500GC Young Lin Instrument Co., Korea). O ₂ , N ₂ , CO and CO ₂ in the effluent were detected with a thermal conductivity detector.

Comparative example 1: through thermochemical treatment Dimethyl Regeneration of catalyst for ether carbonylation reaction

For comparison, the ferrierite catalyst sample after use of an appropriate amount was placed in a muffle electric furnace. Thereafter, the sample was heat-treated at 800° C. for 12 hours at a ramping rate of 10° C./min in air to obtain a comparative catalyst (FER-H).

Experimental example One: unused Catalyst Dimethyl Ether carbonylation reaction

The dimethyl ether carbonylation reaction was carried out in a one-channel, stainless steel fixed-bed reactor. Each channel consisted of a 900 mm long and 16.6 mm inner diameter stainless steel tube. A spacer for catalyst filling was placed in the center of the stainless steel tube reactor. A quartz wool was thinly placed on the spacer, and a ferrierite catalyst was charged in the center of the reactor.

After raising the temperature to 220° C., which is the reaction temperature, in a nitrogen atmosphere, catalyst pretreatment was performed for about 5 hours. Thereafter, the input gas was changed to a reactant gas. CO (carbon monoxide): DME (dimethyl ether):N ₂ (nitrogen) = 45:5:50 In the state of flowing reactant gas with a fixed composition in the volume ratio, gas hourly space velocity (GHSV) 2,000 to 5,000 L Dimethyl ether at a reaction temperature of 220°C and a reaction pressure of 10 bar for a total reaction time of 12 hours or more, sequentially increasing by 1,000 L/kg-cat/h to /kg-cat/h. Carbonylation catalytic reaction experiments were carried out.

The reaction product was automatically and repeatedly analyzed using online gas chromatography (6500GC Young Lin Instrument Co., Korea) connected to the rear end of the reaction system. On-line GC used a Porapak-N column connected to a thermal conductivity detector (TCD), a molecular sieve 13X, and an HP-PLOTQ column connected to a flame ionization detector (FID). Propane, dimethyl ether, methyl acetate, etc., which are combustible hydrocarbons in the product, were detected through the FID column, and nitrogen (N ₂ ), carbon monoxide (CO), and dimethyl ether (DME) in the product were detected through the TCD column. . The conversion rate of dimethyl ether and the selectivity of methyl acetate as the main product according to the catalyst type and reaction time are shown in Table 2 below.

As shown in Table 2, after the initiation of the reaction, the conversion rate of dimethyl ether was decreased due to catalyst deactivation, which appears to be caused by carbon deposition steadily, and the selectivity of methyl acetate was steadily maintained at about 95% or more. After completion of the carbonylation reaction, a ferrierite catalyst after the reaction was obtained (FER-Spent).

Experimental example 2: using a regeneration catalyst Dimethyl Ether carbonylation reaction

The carbonylation reaction of dimethyl ether was carried out in the same manner as in Experimental Example 1, except that the catalysts regenerated in Example 1 and Comparative Example 1 were respectively used. The results are shown in Table 2 below.

catalyst GHSV
(L/kg-cat ^/ h) DME conversion rate
(%) MA selectivity
(%) Deactivation speed
(%/min) FER-Fresh 2,000 20.18 98.11 -0.141 3,000 14.20 97.84 0.015 4,000 10.65 96.73 0.029 5,000 8.68 96.44 0.006 FER-PS
(Example 1) 2,000 20.82 99.21 -0.097 3,000 19.03 99.21 0.013 4,000 15.83 99.22 0.017 5,000 13.09 99.26 0.011 FER-H
(Comparative Example 1) 2,000 2.32 84.37 0.010 3,000 1.23 91.24 0.001 4,000 1.22 92.23 0.002 5,000 1.10 91.41 0.001

Experimental example 3: Dimethyl Of the catalyst and regeneration catalyst after the ether carbonylation reaction TGA analysis

The catalyst after the carbonylation reaction of dimethyl ether and the catalyst after the dielectric barrier discharge (DBD) plasma regeneration under saturated steam flow were subjected to thermogravimetric analysis (TGA) to measure the total weight of coke formed in the catalyst after the reaction. I did. In particular, all catalysts were heated from 30° C. to 1,000° C. in air at a ramping speed of 30° C./min (TG209 F1 Libra, Germany). The mass reduction in the catalyst after the reaction was calculated.

As shown in FIG. 3, the carbonaceous residual material was analyzed through TGA analysis of the catalyst and regeneration catalysts after the reaction. Table 3 shows the TGA measurement results. The coke deposited in the catalyst after the reaction and the regeneration catalysts was heated and removed at a constant heating rate (10° C./min) under an air flow, and the relationship between the temperature and the mass percentage (mass reduction rate) was plotted. From the TGA analysis results, it was experimentally confirmed that coke was pyrolyzed by the mass reduction of the catalyst. In the case of ferrierite, it was about 0.73%, and in the case of the catalyst regenerated by heat treatment, it was about 0%, and almost no mass reduction was found. From this, a relatively high level of coke removal of the heat treatment catalyst was confirmed.

Catalyst after reaction &
Regeneration catalyst Mass loss (%) (0~200℃) (200~400℃) (400~700℃) (700℃ or less) FER-Spent 4.26 1.79 2.14 8.19 FER-PS (Example 1) 6.05 0.72 0.73 7.50 FER-H (Comparative Example 1) 4.19 0.30 0 4.49

Experimental example 4: Dimethyl Analysis of gas physical adsorption of catalyst and regeneration catalyst after ether carbonylation reaction

Table 4 shows the results of gas physical adsorption of the catalyst and regeneration catalysts after the carbonylation reaction of dimethyl ether. After the carbonylation reaction of dimethyl ether, a decrease in the surface area, which appears to be due to a large amount of carbon deposition, was observed, and the BET surface area decreased from 431.0 ㎡/g to 175.8 ㎡/g in the case of the microporous structure. As a result, in the case of the microporous structure, the pre-reaction catalyst pore volume of 0.145 cm 3 /g was reduced to 0.068 cm 3 /g.

This reduction in the pore volume of the catalyst can be considered to be due to the deposition of coke occupied inside the micropores of the zeolite catalyst. After the catalyst was regenerated by plasma treatment under saturated steam flow under conditions of 15.0 kV and 1 kHz, the microporous properties S _BET , V _micro (HK) and V _micro (t-plot) of the regenerated catalyst were used. Compared to the microporous properties, the results increased 1.69 times, 1.57 times and 2.09 times, respectively.

For comparison, the catalyst was heat-treated after a carbonylation reaction at 800° C. with aeration. Results of TGA analysis of the heat treatment regeneration catalyst or gas physical adsorption analysis (change in micropore volume of the heat treatment regeneration catalyst by the HK method 0.068 → 0.122 cm3/g, change in the micropore volume of the plasma regeneration catalyst under saturated steam flow 0.068 → 0.107 cm3/ According to g), the residual amount of deposited carbon in the heat treatment regeneration catalyst was small according to the change in the volume of the micropores. From this, catalyst regeneration by heat treatment is effective in removing carbon deposited inside the catalyst, but a study reported that the reduction in _{V micro of the heat treatment regeneration catalyst compared to the pre-reaction catalyst may damage the structure of the catalyst.} (Catalysis Today, 2011, 178: 72-78) a similar trend was observed.

Catalyst after reaction &
Regeneration catalyst S _BET
(㎡/g) S _micro
(㎡/g) S _ex
(㎡/g) V _micro (HK)
(Cm 3 /g) V _micro (t-plot)
(Cm 3 /g) FER-Spent 175.8 124.9 50.87 0.068 0.047 FER-PS (Example 1) 297.1 264.8 32.35 0.107 0.098 FER-H (Comparative Example 1) 325.8 286.0 39.80 0.132 0.112

According to the pore analysis of the pre-reaction ferrierite catalyst, the post-reaction catalyst, and the regeneration catalyst shown in Tables 1 and 4, it was confirmed that most of the samples had a specific surface area and pore volume of a certain level or higher.

It was confirmed that the pores of the catalyst after the carbonylation reaction of dimethyl ether and the catalyst regenerated through a 15 kV plasma under saturated steam flow were partially filled by coke. The amount of coke removed in the pores of the plasma-treated regeneration catalyst under saturated steam flow was relatively smaller than that of the heat treatment regeneration catalyst.

On the other hand, in the case of the catalyst regenerated by the thermochemical catalyst regeneration method, most of the coke was removed, but the surface area, which seemed to be caused by structural modification, decreased, the total volume of micropores and the volume of mesopores increased.

Experimental example 5: Dimethyl X-ray diffraction analysis of catalyst and regeneration catalyst after ether carbonylation reaction

Fig. 2 shows the powder XRD analysis results of the ferrierite catalysts before and after the reaction and after regeneration. The crystal phase peak detected in the ferrierite catalyst before the reaction was maintained in both the catalyst after the reaction and the regeneration catalyst, and from these results, it was understood that the crystal phase of the ferrierite itself was maintained even after the carbonylation reaction and the regeneration treatment.

In particular, this crystallinity was more pronounced in the case of the plasma regeneration catalyst. From these analysis results, it was confirmed that the highly porous structure was stably maintained through plasma regeneration of the ferrierite catalyst at room temperature, pressure, and saturated steam flow after the carbonylation reaction of dimethyl ether.

Experimental example 6: Dimethyl Analysis of ammonia desorption of catalyst and regeneration catalyst after ether carbonylation reaction

_{Ammonia desorption (NH 3} -temperature programmed desorption; NH ₃ -TPD) is performed on the catalyst after the carbonylation reaction of dimethyl ether and the catalyst after the dielectric barrier discharge (DBD) plasma regeneration under saturated steam flow. And the acid point of the regeneration catalyst was analyzed and quantified. About 40 mg of the catalyst was pretreated at 350° C. for about 1 hour under an inert gas (helium) atmosphere. Thereafter, ammonia was blown for adsorption, and unadsorbed ammonia was removed by blowing, and then desorbed by heating from 30°C to 1,000°C at a ramping speed of 10°C/min in air (BELCAT-M, Japan). . The weak/strong acid point was analyzed qualitatively/quantitatively through the ammonia desorption tendency according to the ammonia temperature, and the results are shown in Table 5 and FIG. 4.

Catalyst after reaction &
Regeneration catalyst Acid sites by ammonia desorption (mmol acid sites/g cat.) Weak acid (below 300℃) Strong acid (300-450℃) Total scattered points FER-Fresh 0.347 0.365 0.712 FER-Spent 0.480 0.168 0.648 FER-PS (Example 1) 0.306 0.239 0.545 FER-H (Comparative Example 1) 0.229 0.095 0.324

As a result of the analysis and quantification of the acid point, it was confirmed that the acid point decrease of the heat treatment catalyst was particularly large, and the specific surface area reduction and the acid point decrease tendency of the catalyst due to structural modification were consistent. In addition, in the case of the plasma treatment catalyst under saturated steam flow, it was confirmed through analysis that the acid point was significantly reduced, but this seems to be caused by acid point blocking by residual coke. The carbonylation activity seems to be closely related to the improvement of crystallinity confirmed through X-ray diffraction analysis.

Claims (18)

(1) introducing a zeolite catalyst in which coke is deposited in the pores of the catalyst, which is used for the carbonylation reaction of dimethyl ether into a dielectric barrier discharge type plasma catalyst regeneration device; (2) supplying saturated steam together with air into the plasma catalyst regeneration apparatus; And (3) applying a high voltage to the high voltage electrode in the catalyst regeneration device to generate plasma under the flow of air and saturated steam to remove 5 to 50% by weight of the total immersion coke, wherein the dielectric barrier discharge type plasma catalyst regeneration device A tubular container made of a dielectric material capable of accommodating the zeolite catalyst used in the carbonylation reaction of dimethyl ether; A ground electrode disposed on the outer wall of the tubular container; A high voltage electrode inserted into the zeolite catalyst accommodated in the tubular container so as to be spatially spaced apart from the tubular container, and applied with a voltage higher than that of the ground electrode; A fixing part for fixing the zeolite catalyst contained in the tubular container to be located in a predetermined area; Saturated steam supply; An air supply unit generating a flow of air to transfer saturated steam into the catalyst regeneration device; And a power supply for providing a regulated voltage to the high voltage electrode, a method for regenerating a zeolite catalyst for a carbonylation reaction of dimethyl ether. delete The method for regenerating a zeolite catalyst for carbonylation reaction of dimethyl ether according to claim 1, wherein the regenerated catalyst maintains the microstructure of the zeolite catalyst prior to being used in the carbonylation reaction of dimethyl ether. The method of claim 1, wherein the zeolite catalyst is at least selected from the group consisting of ferrierite, mordenite, MFI (ZSM-5) zeolite, faujasite (FAU) zeolite, and Y-zeolite. One, a method for regenerating a zeolite catalyst for carbonylation reaction of dimethyl ether. The method for regenerating a zeolite catalyst for carbonylation reaction of dimethyl ether according to claim 1, wherein in step (2) the temperature of the saturated steam flow is 10 to 100°C and the pressure is atmospheric pressure. The method for regenerating a zeolite catalyst for carbonylation reaction of dimethyl ether according to claim 1, wherein plasma is generated by dielectric barrier discharge in step (3). The method for regenerating a zeolite catalyst for carbonylation reaction of dimethyl ether according to claim 1, wherein the voltage applied to the high voltage electrode in the catalyst regeneration device in step (3) is 7 to 50 kV. The method for regenerating a zeolite catalyst for carbonylation reaction of dimethyl ether according to claim 1, wherein step (3) is carried out under conditions of a temperature of 1 to 35°C and atmospheric pressure. The method of claim 1, wherein the coke removed by plasma treatment in step (3) is an amorphous carbon or graphitic carbonaceous material, and the amorphous carbon deposit is 70% or more. A method for regenerating a zeolite catalyst for a carbonylation reaction. A zeolite catalyst for carbonylation reaction of dimethyl ether regenerated by the method according to any one of claims 1 and 3 to 9, wherein a zeolite catalyst for carbonylation reaction of fresh dimethyl ether Regenerated zeolite catalyst for carbonylation reaction of dimethyl ether with relatively high dimethyl ether conversion and methyl acetate selectivity compared to. The regenerated zeolite catalyst for carbonylation reaction of dimethyl ether according to claim 10, which exhibits a dimethyl ether conversion rate of 1 to 70% during a reaction time of 10 minutes to 2 hours in a catalyst activity test after regeneration. The regenerated zeolite catalyst for carbonylation reaction of dimethyl ether according to claim 10, which exhibits a methyl acetate selectivity of 90 to 99% in the carbonylation reaction of dimethyl ether. A tubular container made of a dielectric material capable of accommodating a zeolite catalyst used in the carbonylation reaction of dimethyl ether; A ground electrode disposed on the outer wall of the tubular container; A high voltage electrode inserted into the zeolite catalyst accommodated in the tubular container so as to be spatially spaced apart from the tubular container, and applied with a voltage higher than that of the ground electrode; A fixing part for fixing the zeolite catalyst contained in the tubular container to be located in a predetermined area; Saturated steam supply; An air supply unit generating a flow of air to transfer saturated steam into the catalyst regeneration device; And a power supply for providing a regulated voltage to the high voltage electrode, wherein the high voltage is applied to the high voltage electrode to generate a plasma under the flow of air and saturated steam, so that 5 to 50% by weight of the total coke deposited in the pores of the zeolite catalyst is Used to remove, dielectric barrier discharge type plasma catalyst regeneration device. The apparatus for regenerating a dielectric barrier discharge type plasma catalyst according to claim 13, wherein the zeolite catalyst to be regenerated is supported by a fixing portion and accommodated in a portion covered by a ground electrode in the tubular container. (a) synthesizing methyl acetate by carbonylating dimethyl ether in the presence of a zeolite catalyst for carbonylation reaction of dimethyl ether; (b) introducing a zeolite catalyst in which coke is deposited in the pores of the catalyst, which is used for the carbonylation reaction of dimethyl ether into the dielectric barrier discharge type plasma catalyst regeneration apparatus; (c) supplying saturated water vapor together with air into the plasma catalyst regeneration apparatus; And (d) applying a high voltage to the high voltage electrode in the catalyst regeneration device to generate plasma under the flow of air and saturated steam to remove 5 to 50% by weight of the total immersion coke. And (e) synthesizing methyl acetate by carbonylating dimethyl ether in the presence of a regenerated zeolite catalyst, wherein the dielectric barrier discharge plasma catalyst regeneration device is used for the carbonylation reaction of dimethyl ether. A tubular container made of a dielectric material capable of accommodating a catalyst; A ground electrode disposed on the outer wall of the tubular container; A high voltage electrode inserted into the zeolite catalyst accommodated in the tubular container so as to be spatially spaced apart from the tubular container, and applied with a voltage higher than that of the ground electrode; A fixing part for fixing the zeolite catalyst contained in the tubular container to be located in a predetermined area; Saturated steam supply; An air supply unit generating a flow of air to transfer saturated steam into the catalyst regeneration device; And a power supply for providing a regulated voltage to the high voltage electrode. delete The method of claim 15, wherein the carbonylation reaction of dimethyl ether in step (a), step (e) or both is carried out under conditions of a temperature of 150 to 300 °C and a pressure of 5 to 30 bar. Method for producing methyl acetate by carbonylation reaction. The method for producing methyl acetate according to claim 15, wherein steps (d) and (e) are carried out at least once.

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