KR102199485B1 - Method of preparing catalyst for single stage water gas shift reaction - Google Patents

Abstract

The present invention relates to a method for preparing a catalyst for a water gas transfer reaction, specifically, a copper-based for a water gas transfer reaction having enhanced low-temperature reactivity suitable for a water gas transfer reaction, showing high activity and stability even at low temperatures. It relates to a method for producing a catalyst.

Description

[Method of preparing catalyst for single stage water gas shift reaction}

The present invention relates to a method for preparing a catalyst for a water gas transfer reaction, specifically, a catalyst for a water gas transfer reaction having enhanced low-temperature reactivity suitable for a water gas transfer reaction, showing high activity and stability even at low temperatures. It relates to a manufacturing method.

In recent years, as the energy security problem caused by the use of fossil fuels and the risk of GHG emissions have increased, international interest in the efficient production of hydrogen, a new energy, is increasing. Hydrogen is a clean energy that emits only water without emitting carbon dioxide during combustion, and is attracting attention as a future energy source. As a previous stage in a society that produces hydrogen without the use of fossil fuels, the method to reduce greenhouse gas emissions while using existing infrastructure and gradually convert to a hydrogen economy society is the method of using hydrogen produced from hydrocarbons. Currently, large-scale hydrogen production systems are commercially available, but the problem of building an infrastructure for distribution and storage of hydrogen remains an economic barrier. Therefore, in order to establish an efficient supply infrastructure for fuel cells and to realize an integrated hydrogen production system, it is necessary to develop a fuel reformer of medium and small size. However, due to the difficulty of scale-down due to space constraints and the decrease in thermal efficiency due to system miniaturization, technology development is difficult. The U.S. Department of Energy (DOE) has developed small and medium-sized fuel reformers internationally through the International Energy Agency (IEA) program, and is a new heat for gas equipment-level integrated fuel reformers that ensure ease of operation. And system integration engineering technology is being proposed.

Fuel reforming systems generally produce hydrogen through reforming of hydrocarbon fuels, and among them, hydrogen production using natural gas is the most economical method of producing hydrogen, and its proportion reaches about 90%. For hydrogen production from natural gas, desulfurization (DeS), steam reforming of methanol (SRM), water-gas shift (WGS), and selective oxidation (PROX) are required. It is required sequentially, and the catalyst for each reaction is a key factor in determining the production efficiency of hydrogen.

Existing WGS process is divided into two processes: high temperature water gas transfer reaction (HT-WGS: High temperature WGS) and low temperature water gas transfer reaction (LT-WGS: Low temperature WGS) due to thermodynamic limitations, resulting in a high reactor cost and high reactor volume. There is a drawback of getting bigger.

For compact/high efficiency of the WGS process, single stage WGS, which can perform both HT-WGS and LT-WGS at the same time, is proposed as a core technology, and it is suggested to perform the WGS reaction at a thermodynamically advantageous low temperature. Suitable. First, in the case of WGS, a higher processing capacity than the existing two-stage WGS is required, and a large temperature change may occur due to an exothermic reaction, so high performance of the catalyst and resistance to sintering are required. Recently, a platinum (Pt)-based catalyst and a copper (Cu)-based catalyst for WGS have been studied, but they suffer from difficulties due to the high price and low low temperature reactivity of platinum. Therefore, it is absolutely necessary to develop a highly active/high durability catalyst with enhanced low-temperature reactivity suitable for WGS reaction.

In order to solve the above problems, the present inventors prepared a copper-zinc-aluminum (Cu-Zn-Al) catalyst as a copper-based catalyst, and changed the composition ratio, production method, and cocatalyst of the catalyst, and then evaluated the reaction performance. The present invention was completed by developing a method for producing a catalyst for a water gas transfer reaction, which has high activity and stability at low temperatures.

Hyun-Seog Roh, Hari S. Potdar, Dae-Woon Jeong, Ki-Sun Kim, Jae-Oh Shim, Won-Jun Jang, Kee Young Koo, Wang Lai Yoon, "Synthesis of highly active nano-sized (1 wt. % Pt/CeO2) catalyst for water gas shift reaction in medium temperature application", Catalysis Today, 185 (2012), 113-118. Paweł Kowalik, Marcin Konkol, Katarzyna Antoniak, Wiesław Prochniak, Paweł Wiercioch, "The effect of the precursor aging on properties of the Cu/ZnO/Al2O3 catalyst for low temperature water-gas shift (LT-WGS)", Journal of Molecular Catalysis A: Chemical, 392 (2014), 127-133.

It is an object of the present invention to provide a method for producing a catalyst for a water gas transfer reaction having enhanced low-temperature reactivity suitable for a water gas transfer reaction, which exhibits high activity and stability even at a low temperature.

In order to achieve the above object, the present invention

1) dissolving and heating a copper precursor, a zinc precursor, and an aluminum precursor to prepare an aqueous precursor solution;

2) adding and titrating a precipitant to the aqueous precursor solution of step 1);

3) aging the appropriate aqueous precursor solution in step 2) at 20 to 90° C. for 48 to 148 hours and washing to obtain a precipitate;

4) drying the precipitate obtained in step 3) at 90 to 120°C;

5) It provides a method for producing a catalyst for water gas transfer reaction comprising the step of calcining the precipitate dried in step 4) at 250 to 450°C for 4 to 8 hours.

In addition, the present invention provides a water gas transfer method comprising the step of using the water gas transfer reaction catalyst prepared according to the above method as a single catalyst.

In the present invention, a copper-zinc-aluminum (Cu-Zn-Al) catalyst was prepared by using a co-precipitation method, and by deriving an optimum composition ratio and an optimum manufacturing method of the catalyst, copper- Since it has been confirmed that a zinc-aluminum catalyst can be prepared, the catalyst prepared according to the method of the present invention can be effectively used as a catalyst for water gas transfer reaction.

1 is a diagram schematically illustrating a water gas transfer reaction apparatus using a catalyst prepared according to an embodiment of the present invention.
2 is a copper-zinc-aluminum (Cu-Zn-Al) prepared by fixing the composition ratio of copper (Cu): zinc (Zn) to 1:1 and varying the content of aluminum (Al) according to an embodiment of the present invention. It is a diagram showing the results of XRD analysis of the catalyst.
3 is a diagram showing the XRD analysis result of a Cu-Zn-Al catalyst prepared by varying the composition ratio of Cu:Zn according to an embodiment of the present invention.
4 is a diagram showing the TPR analysis results of a Cu-Zn-Al catalyst prepared by fixing a composition ratio of Cu:Zn to 1:1 and varying Al content according to an embodiment of the present invention.
5 is a diagram showing the TPR analysis result of a Cu-Zn-Al catalyst prepared by varying the composition ratio of Cu:Zn according to an embodiment of the present invention.
6 is a diagram showing the CO conversion rate of a Cu-Zn-Al catalyst prepared by fixing a composition ratio of Cu:Zn to 1:1 and varying Al content according to an embodiment of the present invention.
7 is a diagram showing the CO conversion rate of a Cu-Zn-Al catalyst prepared by varying the composition ratio of Cu:Zn according to an embodiment of the present invention.
FIG. 8 is a diagram showing TPR analysis results of a Cu-Zn-Al catalyst prepared in a different order when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
9 is a diagram showing the CO conversion rate of a Cu-Zn-Al catalyst prepared in a different order when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
10 is a diagram showing the TPR analysis result of a Cu-Zn-Al catalyst prepared by varying an appropriate time when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
11 is a diagram showing CO conversion of a Cu-Zn-Al catalyst prepared by varying an appropriate time when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
12 is a diagram showing the TPR analysis results of a Cu-Zn-Al catalyst prepared by varying an appropriate pH when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
13 is a diagram showing CO conversion of a Cu-Zn-Al catalyst prepared by varying an appropriate pH when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
14 is a diagram showing TPR analysis results of a Cu-Zn-Al catalyst prepared by varying the aging temperature when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
15 is a diagram showing the CO conversion rate of a Cu-Zn-Al catalyst prepared by varying the aging temperature when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
16 is a diagram showing the TPR analysis result of a Cu-Zn-Al catalyst prepared by varying the aging time when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
17 is a diagram showing CO conversion of a Cu-Zn-Al catalyst prepared by varying the aging time when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
18 is a diagram showing the TPR analysis result of a Cu-Zn-Al catalyst prepared by varying the sintering temperature when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
19 is a view showing the CO conversion rate of a Cu-Zn-Al catalyst prepared by varying the sintering temperature when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
20 is a diagram showing the CO conversion rate over time of a Cu-Zn-Al catalyst prepared by varying the sintering temperature when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
FIG. 21 is a diagram showing CO conversion of a Cu-Zn-Al catalyst prepared by adding a cocatalyst when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
22 is a diagram showing CO conversion between a Cu-Zn-Al catalyst and a commercial catalyst prepared under optimal production conditions according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail.

The present invention

1) dissolving and heating a copper precursor, a zinc precursor, and an aluminum precursor to prepare an aqueous precursor solution;

2) adding and titrating a precipitant to the aqueous precursor solution of step 1);

3) aging the appropriate aqueous precursor solution in step 2) at 20 to 90° C. for 48 to 148 hours and washing to obtain a precipitate;

4) drying the precipitate obtained in step 3) at 90 to 120°C;

5) It provides a method for producing a catalyst for water gas transfer reaction comprising the step of calcining the precipitate dried in step 4) at 250 to 450°C for 4 to 8 hours.

In the present invention, the copper precursor, the zinc precursor, and the aluminum precursor in step 1) may be nitrate or nitrate hydrate, and specifically, may be nitrate hydrate. For example, the copper precursor may be copper nitrate (Cu(NO ₃ ) ₃ ) or copper nitrate hydrate (Cu(NO ₃ ) ₃ ·xH ₂ O), and the zinc precursor is zinc nitrate (Zn(NO ₃ ) ₂ ) or nitric acid It may be zinc hydrate (Zn(NO ₃ ) ₂ ·6H ₂ O), and the aluminum precursor may be aluminum nitrate (Al(NO ₃ ) ₃ ) or copper nitrate hydrate (Al(NO ₃ ) ₃ ·9H ₂ O), but , But is not limited thereto.

In the present invention, it is preferable to titrate at a pH of 10 to 10.5 in step 2). When the appropriate pH is out of the above range, the reducing power of the catalyst may decrease at a low temperature, thereby reducing catalytic activity.

In addition, the appropriate time in step 2) is preferably less than 90 minutes, more preferably less than 60 minutes, even more preferably less than 30 minutes, even more preferably less than 5 minutes, and 0 minutes, that is, immediately after titration It is most preferred to carry out step 3).

In addition, the titration in step 2) may be performed by adding a precipitant solution to the precursor aqueous solution, or by adding a precursor aqueous solution to the precipitant solution, but it is more preferable to add a precipitant solution to the precursor aqueous solution.

In addition, the precipitant in step 2) may be a potassium hydroxide solution, a sodium hydroxide solution, a potassium carbonate solution, or a sodium carbonate solution, and more specifically, a potassium hydroxide solution, but is not limited thereto. In addition, the precipitant may be added in an amount of 5 to 25% by weight based on the total weight% of the precursor aqueous solution, more specifically in an amount of 10 to 20% by weight, and more specifically in an amount of 13 to 17% by weight. And, more specifically, it may be added in 15% by weight, but is not limited thereto.

In the present invention, the precursor aqueous solution suitable in step 3) is preferably aged at 20 to 90°C for 48 to 148 hours, more preferably aged at 35 to 85°C for 60 to 132 hours, and 37 to 83 It is even more preferable to aged for 66 to 126 hours at ℃, even more preferably aged for 72 to 120 hours at 40 to 80 ℃, most preferably aged for 72 hours at 80 ℃. When the aging temperature is out of the above range, the reducing power of the catalyst may decrease at a low temperature, thereby reducing catalytic activity. If the aging time is less than 48 hours, the reducing power of the catalyst may decrease, and thus catalytic activity may decrease. In addition, when the aging time exceeds 148 hours, the cost increases during the production of the catalyst, which may be economically inefficient.

In the present invention, the precipitate dried in step 5) is preferably calcined at 250 to 450°C for 4 to 8 hours, more preferably calcined at 300 to 440°C for 4.5 to 7.5 hours, and 330 to 430°C It is even more preferable to calcinate at 5 to 7 hours, even more preferable to calcinate at 360 to 420°C for 5 to 7 hours, even more preferable to calcinate at 390 to 410°C for 5 to 7 hours, It is even more preferable to sinter at 395 to 405°C for 5 to 7 hours, and most preferably at 400°C for 6 hours. When the sintering temperature is out of the above range, all Cu(OH) ₂ generated during precursor precipitation is not decomposed into CuO, so that the reducing power of the catalyst decreases, thereby reducing catalytic activity.

In the present invention, the catalyst for water gas transfer reaction preferably comprises 42.5 to 67.5% by weight of copper, 22.5 to 47.5% by weight of zinc and 5 to 15% by weight of aluminum based on the total weight of the catalyst, and the catalyst It is more preferable to include 43 to 67% by weight of copper, 23 to 47% by weight of zinc and 5 to 13% by weight of aluminum, based on the total weight% of the catalyst, 45 to 65% by weight of copper, It is even more preferable to contain 25 to 45% by weight of zinc and 5 to 10% by weight of aluminum, and to contain 65% by weight of copper, 25% by weight of zinc and 10% by weight of aluminum based on the total weight of catalyst. It is most preferred. When the aluminum content is less than 5% by weight, the reducing power of the catalyst may decrease at a low temperature, such as a low-temperature water gas transition reaction temperature, and when the aluminum content exceeds 15% by weight, the copper content in the catalyst and the number of copper atoms on the surface decrease Thus, the reducing power of the catalyst may be lowered.

In addition, the catalyst for the water gas transfer reaction is preferably containing copper: zinc: aluminum in a weight ratio of 42.5 to 67.5: 22.5 to 47.5: 10, and more preferably in a weight ratio of 43 to 67: 23 to 45:10. It is preferable, and it is more preferable to include it in a weight ratio of 44.5 to 65.5: 24.5 to 45.5: 10, even more preferable to include in a weight ratio of 45 to 65: 25 to 45:10, and a weight ratio of 65: 25: 10 It is most preferable to include as. More specifically, the catalyst for the water gas transfer reaction is preferably copper: zinc: aluminum in a weight ratio of 42.5: 42.5: 10 to 67.5: 25.5: 10, and 45: 45: 10 to 65: 25: 10 It is more preferable to include it in a weight ratio, and it is most preferable to include it in a weight ratio of 65:25:10. When the weight ratio of the copper: zinc: aluminum is out of the above range, the reducing power of the catalyst may decrease at low temperatures.

In the present invention, it is preferable that the catalyst for the water gas transfer reaction does not contain a cocatalyst such as platinum, magnesium or silicon. A catalyst exhibiting an excellent conversion rate compared to conventional commercial catalysts can be obtained without using the cocatalyst, and has the advantage of being able to manufacture at a much lower cost compared to known commercial catalysts in terms of manufacturing cost.

The catalyst for water gas transfer reaction prepared by the production method according to the present invention has enhanced low-temperature reactivity and thus exhibits sufficiently high catalytic activity over the entire range of temperatures regardless of each of the high-temperature and low-temperature reactions during the normal water gas transfer reaction. In addition, since it exhibits high stability and high durability, it is useful as a catalyst for a water gas transfer reaction, more specifically, a catalyst for a water gas transfer reaction.

In addition, the present invention provides a water gas transfer method comprising the step of using a water gas transfer reaction catalyst prepared according to the above-described production method as a single catalyst.

Specifically, the catalyst prepared according to the production method of the present invention is charged into the reactor. A mixed gas filled with hydrogen, nitrogen, methane, carbon monoxide, and carbon dioxide is passed through the reactor. Thereafter, water vapor is supplied by matching the concentration of methane, carbon monoxide, and carbon dioxide in the reaction gas and a predetermined ratio. The water vapor may be supplied by using a pump, for example, a syringe pump or a metering pump. The temperature of the steam can be controlled by installing a pre-heater at the top of the reaction gas injection part of the reactor, and the temperature can be controlled by a heating system using PID control. Then, a water gas transfer reaction is performed. In performing the water gas transfer reaction process, in the presence of the catalyst, the reaction temperature may be 150 to 400° C., more specifically 200 to 300° C., and the space velocity of gas (GHSV) 8,001 to 36,050 h ^-1 may be performed. It may be usefully used in a polymer fuel cell (PEMFC) for a fuel cell for a water gas transfer reaction, and a hydrogen station or ammonia synthesis process, and a petrochemical process.

Hereinafter, the present invention will be described in detail by examples and experimental examples.

However, the following examples and experimental examples are merely illustrative of the present invention, and the contents of the present invention are not limited to the following examples and experimental examples.

< Example 1> Preparation of copper-zinc-aluminum catalyst

A copper-zinc-aluminum (Cu-Zn-Al) catalyst having a composition ratio of 65% by weight of copper, 25% by weight of zinc, and 10% by weight of aluminum was prepared using coprecipitation.

Specifically, Cu(NO ₃ ) ₃ · x H ₂ O (99%, Aldrich) 4.60 g as a copper precursor, Zn(NO ₃ ) ₂ ·6H ₂ O (99%, Aldrich) 2.80 g as a zinc precursor, and an aluminum precursor 2.25 g of Al(NO ₃ ) ₃ ·9H ₂ O (99%, Aldrich) was dissolved in 0.5 L of distilled water and then heated to 80°C. Then, a 15 wt% potassium hydroxide (KOH) solution was added as a precipitant at constant temperature, and the pH value was adjusted to 10, followed by titration, and then aged at 80° C. for 3 days. It was washed with distilled water several times to remove the K ⁺ ions remaining in the aged solution. The precipitate obtained after washing was dried at 110° C. and then calcined at 400° C. for 6 hours to prepare a copper-zinc-aluminum catalyst.

< Example 2> Characterization of catalyst

<2-1> XRD analysis

X-ray diffraction (XRD) to determine the crystallinity and composition of the prepared copper-zinc-aluminum catalyst was measured using a Rigaku D/MAX-IIIC equipment, and measured at CuK radiation, 40 kV, and 40 mA. The crystal size was calculated by the JADE 5.0 (XRD pattern processing software, Material Data, INC.) program using the Scherrer equation.

<2-2> BET analysis

Brunauer-Emmett-Teller (BET) surface area analysis of the prepared copper-zinc-aluminum catalyst was performed by measuring the adsorption amount of N ₂ gas at -196°C using an ASAP 2010 (Micromeritics Co.) apparatus. The measurement sample amount was about 0.1 g to 0.2 g, and the pretreatment was performed at 110° C. in a vacuum of 0.5 mmHg or less for 12 hours.

<2-3> TPR analysis

TPR analysis of the prepared copper-zinc-aluminum catalyst was measured using an Autochem 2920 (Micromeritics Co.) apparatus. A 50 mg sample was used, and the TPR analysis result was obtained by analyzing the reduction characteristics of the catalyst according to the temperature change in the process of heating up to 400°C (temperature increase rate: 10°C/min) in 10% H ₂ /Ar atmosphere.

<2-4> N ₂ O - chemisorption analysis

The N ₂ O-chemisorption analysis of the prepared copper-zinc-aluminum catalyst was measured by an N ₂ O surface titration method using Autochem 2920 (Micromeritics Co.). Prior to the N ₂ O titration, 0.1 g of the catalyst sample was reduced at 200° C. for 1 hour in 10% H ₂ /Ar atmosphere. N ₂ O consumption and N ₂ discharge were measured at 60°C with a thermal conductivity detector (TCD). The reduced Cu is oxidized by the _{N 2 O (N 2 O +} 2Cu → Cu 2 O + N 2), N 2 O / Cu 2 ratio to 0.5, × 10 for the surface concentration of Cu metal 1.46 ¹⁹ Cu atoms / was assumed to be m ² . The Cu particle size was calculated using the formula 6000/(8.92×Cu metal surface area/Cu fraction in gram catalyst).

< Example 3> Water gas transfer reaction analysis using catalyst

<3-1> Water gas transfer reaction device fabrication

A water gas transfer reaction (WGS) reaction apparatus using a copper-zinc-aluminum catalyst prepared as shown in the schematic diagram of FIG. 1 was prepared.

Referring to FIG. 1, the WGS catalytic reaction device includes a mass flow controller (MFC) 10, a pre-heater 20, a syringe pump 30, a quartz tube 40, a furnace 50, a cooler 60, and It is composed of Micro-Gc (70). Reactive gas flows into the MFC 10. The reaction gas flow rate was precisely adjusted using the 5850E model (Brooks). Depending on the type of reaction gas used (H ₂ , N ₂ , CH ₄ , CO, CO ₂ ), the flow rate correction and flow rate control range were applied differently. The pre-heater 20 is located at the top of the reaction gas injection part of the quartz tube 40 and supplies H ₂ O required for the WGS reaction in the state of steam. The pre-heater was manufactured by attaching a heating wire to a 1/4" stainless steel tube, and a thermocouple was installed in the middle to measure the temperature. H ₂ O was injected after the catalytic reduction was completed, and the pre-heater was pre- The heater was operated and adjusted to maintain about 180° C. The syringe pump 30 is located between the MFC and the pre-heater to supply H ₂ O required for the WGS reaction. After filling a 50 ml syringe with distilled water, use a syringe pump. the flow rate of _{H 2 O H 2 O / (} CH 4 + CO + CO 2) was fed by controlling such that the ratio is 2.0. Syringe pump (30) was used as the KDS100 infusion pump (KD Scientific, Inc.), flow rate control range It was set at 0.20 ml/h to 426 ml/h. A quartz tube 40 was mounted in the furnace 50 to control the reactor temperature. The quartz tube 40 was used as 1/4”. A quartz tube 40 was used for fixing the catalyst bed. A quartz cotton pad was inserted into the tube stop, and a catalyst with a size of 60 mesh to 100 mesh was used to prevent channeling and pressure drop, and a thermocouple was installed at the stop of the catalyst layer to measure the temperature of the catalyst bed inside the quartz tube. The furnace used a 2.2KW-class electric furnace that can be controlled up to 1000° C. The cooler 60 removes H ₂ O remaining after the WGS reaction by passing gas after the reaction. The temperature of the cooler is maintained at 2.2° C. The cooler was controlled accurately with a digital PID controller, the JSRC-13C model (JSR) was used, and the temperature control range was -45℃ to 120℃ The cooling water used in the cooler was prepared by mixing ethylene glycol and water. Micro-GC (70) analyzes the gas composition and ratio after the WGS reaction, agilent 3000A Micro-GC (agilent technologies) was used. Hannel 1 was equipped with a Molecular sieve column for H ₂ , N ₂ , CO and CH ₄ gas analysis, and a plot-U column was mounted on channel 2 for CO ₂ gas analysis.

<3-2> Water gas transfer reaction using catalyst

The WGS reaction analysis was performed using the catalyst prepared in <Example 1> and the WGS catalytic reaction apparatus prepared in Example <3-1>.

Specifically, the WGS reaction experiment was carried out in a temperature range of 200 ℃ ~ 240 ℃. 0.109 g of catalyst was injected, and a thermocouple was installed in the catalyst layer so that the actual reaction temperature could be measured. Before proceeding with the catalytic reaction, the temperature was raised to 200°C at a rate of 3.3°C/min in 2% H ₂ /N ₂ atmosphere, and a reduction process was performed for 1 hour. After the reduction was completed, the WGS reaction was performed while flowing a reaction gas (CH ₄ : 1.0%, CO ₂ : 10.0%, CO: 9.0%, H ₂ : 60.1%, N ₂ : 19.9%). The H ₂ O/(CH ₄ + CO + CO ₂ ) ratio of the reaction gas was fixed at 2.0, and the space velocity was performed at 8,001 h ^-1 . The injected H ₂ O was quantitatively injected using a syringe pump, and water vapor was generated while passing through the pre-heater (180°C) before the catalytic reaction. After the reaction, the gas used a cooler to remove residual moisture. After the reaction from which moisture was finally removed, the gas was analyzed using an on-line micro-gas chromatograph (Agilent 3000A). The CO conversion rate was calculated by applying the concentration of the exhaust gas after the WGS reaction to the following [Equation 1].

[Equation 1]

CO conversion = (F _{co ,in} -F _{co ,out} )/F _{co ,in}

In addition, the catalyst stability test was performed at a space velocity of 16,002 h ^-1 and 240°C for 200 hours.

< Experimental example 1> Check the catalytic activity according to the composition ratio of copper, zinc, and aluminum in a copper-zinc-aluminum catalyst

In order to investigate the copper-zinc-aluminum catalyst activity according to the content of copper, zinc and aluminum, after preparing a copper-zinc-aluminum catalyst having different composition ratios of copper, zinc and aluminum, XRD analysis, BET analysis, TPR analysis and WGS reaction Analysis was carried out.

Specifically, a copper-zinc-aluminum catalyst was prepared in the same manner as in Example 1, except that a catalyst having a composition ratio as shown in [Table 1] was prepared by adjusting the mixing amount of the copper precursor, the zinc precursor, and the aluminum precursor. .

Sample Composition ratio of catalyst (% by weight) One Cu 35 wt% / Zn 35 wt% / Al 30 wt% 2 40 wt% Cu / 40 wt% Zn / 20 wt% Al 3 Cu 42.5 wt% / Zn 42.5 wt% / Al 15 wt% 4 Cu 45% by weight / Zn 45% by weight / Al 10% by weight 5 Cu 47.5 wt% / Zn 47.5 wt% / Al 5 wt% 6 50 wt% Cu / 50 wt% Zn / 0 wt% Al 7 50 wt% Cu / 40 wt% Zn / 10 wt% Al 8 Cu 60 wt% / Zn 30 wt% / Al 10 wt% 9 65 wt% Cu / 25 wt% Zn / 10 wt% Al 10 Cu 70% by weight / Zn 20% by weight / Al 10% by weight

Then, XRD analysis, BET analysis, TPR analysis, and N ₂ O-chemisorption analysis were performed on the catalyst in the same manner as described in Examples <2-1> to <2-4>. In addition, WGS reaction analysis was performed in the same manner as described in Example <3-2>.

As a result, as shown in FIGS. 2 and 3, as a result of XRD analysis, it was confirmed that the intensity of CuO and ZnO peaks decreased as the Al content of the copper-zinc-aluminum catalyst increased (FIG. 2). In addition, it was confirmed that the intensity of the ZnO peak decreased as the copper:zinc composition ratio of the copper-zinc-aluminum catalyst increased (FIG. 3).

In addition, as shown in Table 2, in the case of the catalyst to which Al was not added (Sample 6) as a result of BET analysis, it was confirmed that the catalyst surface area was the lowest, whereas the BET surface area of the catalyst increased as Al was added. In particular, when the Al content was increased from 5% by weight to 20% by weight, the surface area of the catalyst also increased, but when the Al content increased from 20% by weight to 30% by weight, it was confirmed that the surface area of the catalyst rather decreased. In addition, it was confirmed that the BET surface area of the catalyst increased as the copper:zinc composition ratio of the copper-zinc-aluminum catalyst increased. Meanwhile, as a result of XRD analysis, it was confirmed that the Cu crystal size of the catalyst was between 12 nm and 15 nm, and that the sample 9 catalyst had the lowest Cu crystal size at 12.3 nm (Table 2).

In addition, as shown in Figs. 4 and 5, in the case of the catalyst (Sample 6) to which Al was not added, it was confirmed that the reduction peak was exhibited at a higher temperature than the catalysts to which Al was added, and the reducing power was improved due to the addition of Al. . However, it was confirmed that the area of the reduction peak decreased as the Al content increased (FIG. 4). In addition, except for the sample 9 catalyst, it was confirmed that the reduction peak shifted to a higher temperature as the copper:zinc composition ratio increased. In the case of the sample 9 catalyst, it was confirmed that the reduction peak appeared at the lowest temperature and had the highest reducing power (FIG. 5).

In addition, as shown in Table 3, as a result of the N ₂ O-chemisorption analysis, when the Al content of the catalyst increases from 0 to 5% by weight, the number of Cu atoms on the surface increases, whereas the Al content is from 10% to 30% by weight. When increasing, it was confirmed that the number of Cu atoms on the surface decreased. In order to obtain high catalytic activity, the number of Cu atoms dispersed on the surface must be high, and it was confirmed that a high catalytic activity was exhibited when the Al content of the catalyst was 5 to 10% by weight. In addition, except for the sample 10 catalyst, it was confirmed that the number of surface Cu atoms increased as the copper:zinc composition ratio increased. In particular, it was confirmed that the number of Cu atoms on the surface of the sample 9 catalyst was the highest.

In addition, as shown in FIGS. 6 and 7, it was confirmed that the result of WGS analysis showed a high CO conversion rate in all temperature ranges when the Al content of the catalyst was 5 to 10% by weight (FIG. 6 ). In addition, it was confirmed that the higher the copper:zinc composition ratio, the higher the CO conversion rate, except for the sample 10 catalyst (FIG. 7).

Therefore, when the above results are summarized, it was confirmed that the copper-zinc-aluminum catalyst is suitable as a catalyst for the water gas transfer reaction. In addition, it was confirmed that the optimum aluminum content range was 5 to 15% by weight as a copper-zinc-aluminum catalyst having high catalytic activity. In addition, as a copper-zinc-aluminum catalyst having high catalytic activity, the optimum copper:zinc:aluminum composition ratio range is 45:45:10 to 65:25:10, of which 65:25:10 shows the best catalytic activity. Was confirmed.

< Experimental example 2> Confirmation of catalytic activity according to the manufacturing method in a copper-zinc-aluminum catalyst

In order to find out the effect of the manufacturing method on the catalyst performance when manufacturing a copper-zinc-aluminum catalyst, TPR analysis and WGS after preparing a catalyst by changing the proper sequence, appropriate time, proper pH, aging temperature, aging time, and calcination temperature. Reaction analysis was performed.

<2-1> Confirmation of catalytic activity according to the proper sequence

In order to find out the effect of the titration sequence on the catalyst performance when preparing the copper-zinc-aluminum catalyst, TPR analysis and WGS reaction analysis were performed after preparing the catalyst by changing the titration sequence.

Specifically, <Example 1> and <Example 1> except that a copper precursor, a zinc precursor, and an aluminum precursor aqueous solution heated in a 15% by weight potassium hydroxide (KOH) solution as a precipitant at constant temperature were added and the pH value was adjusted to 10. A catalyst (Cu-Zn-Al reverse) was prepared in the same way. Then, for each of the catalyst prepared above (Cu-Zn-Al reverse) and the catalyst prepared in <Example 1> (Cu-Zn-Al normal), the method described in Example <2-3> and TPR analysis was performed in the same way. In addition, WGS reaction analysis was performed in the same manner as described in <Example 3>.

As a result, as shown in FIGS. 8 and 9, as a result of TPR analysis, it was confirmed that the Cu-Zn-Al normal catalyst had a higher reducing power by reducing CuO species at a lower temperature than the Cu-Zn-Al reverse catalyst (FIG. 8 ). In addition, as a result of the WGS reaction analysis, it was confirmed that the Cu-Zn-Al normal catalyst showed higher catalytic activity in all temperature regions than the Cu-Zn-Al reverse catalyst (FIG. 9).

Through the above results, it was confirmed that the optimal titration method when preparing a copper-zinc-aluminum catalyst by coprecipitation is a method of administering a precipitant to the aqueous precursor solution.

<2-2> Confirmation of catalytic activity according to appropriate time

In order to find out the effect of the appropriate time on the catalyst performance when preparing the copper-zinc-aluminum catalyst, TPR analysis and WGS reaction analysis were performed after preparing the catalyst by varying the appropriate time.

Specifically, the catalyst was prepared in the same manner as in <Example 1>, except that a 15 wt% potassium hydroxide (KOH) solution was added as a precipitant at constant temperature, the pH value was adjusted to 10, and titrated for 0, 30, or 60 minutes. Was prepared. Then, for each of the catalysts prepared above, TPR analysis was performed in the same manner as described in Example <2-3>. In addition, WGS reaction analysis was performed in the same manner as described in <Example 3>.

As a result, as shown in Figs. 10 and 11, as a result of TPR analysis, it was confirmed that the catalyst having an appropriate time of 0 minutes reduced the CuO species at the lowest temperature to have the highest reducing power (FIG. 10). In addition, as a result of the WGS reaction analysis, it was confirmed that the catalyst having an appropriate time of 0 minutes exhibits high catalytic activity in all temperature regions (FIG. 11).

Through the above results, it was confirmed that the optimum titration time was 0 minutes when the copper-zinc-aluminum catalyst was prepared by the coprecipitation method.

<2-3> Confirmation of catalytic activity according to proper pH

In order to find out the effect of the appropriate pH on the catalyst performance when preparing the copper-zinc-aluminum catalyst, TPR analysis and WGS reaction analysis were performed after preparing the catalyst by varying the appropriate pH.

Specifically, a catalyst was prepared in the same manner as in <Example 1> except for titration by adding a 15 wt% potassium hydroxide (KOH) solution as a precipitant at constant temperature and adjusting the pH value to 9.5, 10, 10.5 or 11. I did. Then, for each of the catalysts prepared above, TPR analysis was performed in the same manner as described in Example <2-3>. In addition, WGS reaction analysis was performed in the same manner as described in <Example 3>.

As a result, as shown in FIGS. 12 and 13, it was confirmed that when the appropriate pH increased from 9.5 to 10 as a result of TPR analysis, the reduction peak moved to a low temperature and the reducing power of the catalyst was enhanced. On the other hand, it was confirmed that when the pH was increased from 10 to 11, the reduction peak moved to a high temperature and the reducing power of the catalyst decreased (FIG. 12). In addition, it was confirmed that when the appropriate pH was 10 and 10.5, high catalytic activity was exhibited in all temperature regions (FIG. 13).

Through the above results, it was confirmed that the optimum pH was 10 to 10.5 when the copper-zinc-aluminum catalyst was prepared by the coprecipitation method.

<2-4> Confirmation of catalytic activity according to aging temperature

In order to find out the effect of the aging temperature on the catalyst performance when preparing the copper-zinc-aluminum catalyst, the catalyst was prepared by varying the aging temperature, and then TPR analysis and WGS reaction analysis were performed.

Specifically, a catalyst was prepared in the same manner as in <Example 1>, except that the aging temperature was changed to 20, 40, 60, 80 or 90°C during aging. Then, for each of the catalysts prepared above, TPR analysis was performed in the same manner as described in Example <2-3>. In addition, WGS reaction analysis was performed in the same manner as described in <Example 3>.

As a result, as shown in FIGS. 14 and 15, as a result of TPR analysis, when the aging temperature is 40°C, 60°C or 80°C, a reduction peak appears in a lower temperature region than when the aging temperature is 20°C or 90°C. It was confirmed that the reducing power was improved (FIG. 14). In addition, it was confirmed that when the aging temperature is 40°C, 60°C, or 80°C, high catalytic activity is displayed, and when the aging temperature is 80°C, the highest catalytic activity is displayed (FIG. 15).

Through the above results, it was confirmed that the aging temperature was 40 to 80°C when the copper-zinc-aluminum catalyst was prepared by coprecipitation.

<2-5> Confirmation of catalytic activity according to aging time

In order to find out the effect of aging time on catalyst performance when preparing a copper-zinc-aluminum catalyst, TPR analysis and WGS reaction analysis were performed after preparing a catalyst by varying the aging time.

Specifically, a catalyst was prepared in the same manner as in <Example 1>, except that the aging time was changed to 8, 48, 72 or 120 hours during aging. Then, for each of the catalysts prepared above, TPR analysis was performed in the same manner as described in Example <2-3>. In addition, WGS reaction analysis was performed in the same manner as described in <Example 3>.

As a result, as shown in FIGS. 16 and 17, as a result of the TPR analysis, it was confirmed that the temperature of the reduction peak moved to a low temperature as the aging time increased, and the reducing power of the catalyst was improved (FIG. 16). In addition, it was confirmed that when the aging time was 72 hours or longer, high catalytic activity was exhibited in all temperature regions. In addition, it was confirmed that the CO conversion rate reached the equilibrium conversion rate at 220° C. or higher (FIG. 17).

Through the above results, it was confirmed that the aging time was 72 to 120 hours when the copper-zinc-aluminum catalyst was prepared by the coprecipitation method.

<2-6> At firing temperature Catalytic activity check

In order to find out the effect of the sintering temperature on the catalyst performance when preparing the copper-zinc-aluminum catalyst, the catalyst was prepared by varying the sintering temperature, and then TPR analysis and WGS reaction analysis were performed.

Specifically, a catalyst was prepared in the same manner as in <Example 1>, except that the firing temperature was changed to 250, 400 or 450°C during firing. Then, for each of the catalysts prepared above, TPR analysis was performed in the same manner as described in Example <2-3>. In addition, WGS reaction analysis and catalyst stability test were performed in the same manner as described in <Example 3>.

As a result, as shown in FIGS. 18 to 20, as a result of TPR analysis, it was confirmed that the reduction peak temperature of the catalyst calcined at 250°C was the lowest. However, it was confirmed that a small active peak was shown (FIG. 18). In addition, as a result of the WGS reaction analysis, it was confirmed that a high catalytic activity was exhibited when the firing temperature was 250°C or 400°C (FIG. 19). In addition, as a result of the catalyst stability test, it was confirmed that the catalyst fired at 250°C showed stable catalytic activity for 100 hours, but the catalytic activity gradually decreased thereafter. On the other hand, it was confirmed that the catalyst fired at 400° C. showed very stable activity without a significant decrease in activity for 200 hours (FIG. 20 ).

Through the above results, it was confirmed that the optimum calcination temperature was 400°C when the copper-zinc-aluminum catalyst was prepared by the coprecipitation method.

Therefore, according to the results of Experimental Examples <2-1> to <2-6>, when preparing a copper-zinc-aluminum catalyst by a coprecipitation method, a method of adding a precipitant to the precursor aqueous solution by an appropriate method, the appropriate time is 0 minutes, When the pH is 10 to 10.5, the aging temperature is 40 to 80°C, the aging time is 72 to 120 hours, and the calcination temperature is 400°C, it has been confirmed that it shows excellent catalytic activity as a catalyst for water gas transfer reaction.

< Experimental example 3> In the copper-zinc-aluminum catalyst Cocatalyst Confirmation of catalytic activity according to addition

In order to find out the effect of the addition of the cocatalyst on the catalyst performance in the preparation of the copper-zinc-aluminum catalyst, the catalyst was prepared by adding a cocatalyst during the preparation of the catalyst, followed by TPR analysis and WGS reaction analysis.

Specifically, it was prepared by the same method as described in <Example 1>, but when preparing a precursor mixture solution, Cu(NO ₃ ) ₃ · x H ₂ O (99%, Aldrich) 4.60 g as a copper precursor, and Zn as a zinc precursor. (NO ₃ ) ₂ ·6H ₂ O (99%, Aldrich) 2.57 g, Al(NO ₃ ) ₃ ·9H ₂ O (99%, Aldrich) 2.25 g as an aluminum precursor, Pt(NH ₃ ) ₄ as a cocatalyst precursor (NO ₃ ) ₂ (99%, Aldrich) 0.24 g, Mg(NO ₃ ) ₂ 6H ₂ O(99%, Aldrich) 0.64 g or C ₈ H ₂₀ O ₄ Si (TEOS, Tetraethyl orthosilicate) (98%, Aldrich ) 0.45 g was dissolved in 0.5 L of distilled water. Then, for each of the catalysts prepared above, WGS reaction analysis was performed in the same manner as described in <Example 3>.

As a result, as shown in FIG. 21, it was confirmed that the Cu-Zn-Al catalyst to which no cocatalyst was added exhibited a high catalytic activity of 80% or more in all temperature ranges (FIG. 21).

< Experimental example 4> Comparison of catalytic activity between copper-zinc-aluminum catalysts and commercial catalysts

WGS analysis was performed to compare the catalytic activity of the catalyst according to the present invention and a commercial catalyst.

Specifically, WGS analysis was performed on each of the catalyst prepared under the optimum conditions in <Example 1> and the commercial catalyst MDC-7. In this case, WGS analysis was performed in the same manner as in Example <3-1>, except that the reaction experiment was conducted at a very high space velocity of 36,050 h ^-1 for comparison of catalyst performance. Commercial catalyst MDC-7 is a product on the market as a catalyst for water gas transfer reaction of Clariant.

As a result, as shown in FIG. 22, it was confirmed that the Cu-Zn-Al catalyst according to the present invention exhibited higher catalytic activity than the catalyst used.

Claims (11)

1) dissolving and heating a copper precursor, a zinc precursor, and an aluminum precursor to prepare an aqueous precursor solution;
2) adding a precipitant to the aqueous precursor solution of step 1) and titrating at a pH of 10 to 10.5;
3) aging the appropriate aqueous precursor solution in step 2) at 20 to 90° C. for 48 to 148 hours and washing to obtain a precipitate;
4) drying the precipitate obtained in step 3) at 90 to 120°C;
5) A method for producing a catalyst for a water gas transfer reaction comprising the step of calcining the precipitate dried in step 4) at 250 to 450°C for 4 to 8 hours.
The method of claim 1, wherein the copper precursor, zinc precursor, and aluminum precursor in step 1) are nitrate or nitrate hydrate.
The method of claim 2, wherein the copper precursor, zinc precursor, and aluminum precursor in step 1) are copper nitrate hydrate, zinc nitrate hydrate and aluminum nitrate hydrate, respectively.
delete The method of claim 1, wherein the precursor aqueous solution suitable in step 3) is aged at 35 to 85° C. for 60 to 132 hours.
The method of claim 1, wherein the precipitate dried in step 5) is calcined at 330 to 430°C for 5 to 7 hours.
The method of claim 1, wherein the catalyst for water gas transfer reaction comprises 42.5 to 67.5% by weight of copper, 22.5 to 47.5% by weight of zinc and 5 to 15% by weight of aluminum based on the total weight of the catalyst. , Method for producing a catalyst for water gas transfer reaction.
The method of claim 1, wherein the catalyst for water gas transfer reaction comprises copper: zinc: aluminum in a weight ratio of 42.5 to 67.5: 22.5 to 47.5: 10.
The method of claim 1, wherein the catalyst for water gas transfer reaction does not contain a cocatalyst.
The method of claim 9, wherein the cocatalyst is selected from the group consisting of platinum, magnesium and silicon.
A water gas transfer method comprising the step of using a catalyst for a water gas transfer reaction prepared according to any one of claims 1 to 3 and 5 to 10 as a single catalyst.

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