KR20200043607A - 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 single stage water-gas shift reaction. More specifically, the present invention relates to a method for preparing a copper-based catalyst for a single stage water-gas shift reaction, having enhanced low-temperature reactivity which is suitable for a single stage water-gas shift reaction, and exhibiting high activity and stability even at low temperatures.

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 once, and specifically, exhibits high activity and stability even at low temperatures. It relates to a manufacturing method.

In recent years, international interest in the efficient production of hydrogen, a new energy, has increased as energy security problems due to the use of fossil fuels and crisis awareness about greenhouse gas emissions have increased. Hydrogen is a clean energy that emits only water without emitting carbon dioxide during combustion, and has been spotlighted as a future energy source. As a whole step in a society that produces hydrogen without the use of fossil fuels, a method that can reduce greenhouse gas emissions while using the existing infrastructure and gradually convert it into a hydrogen economy is to use hydrogen produced from hydrocarbons. Currently, a large-scale hydrogen production system is 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 realize an integrated hydrogen production system, it is necessary to develop a medium-sized fuel reformer. However, due to the difficulty of scale-down due to space constraints and the decrease in thermal efficiency due to the miniaturization of the system, it is experiencing difficulties in technology development. The U.S. Department of Energy (DOE) internationally developed small and medium-sized fuel reformers through the International Energy Agency (IEA) implementation program, and opened new lines for integrated gas-level fuel reformers with ease of operation. And systems integration engineering techniques.

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

The 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 high reactor cost and high reactor volume. There is a disadvantage that becomes larger.

For compact / high-efficiency of WGS process, HT-WGS and LT-WGS can be performed at the same time, and it is suggested that a water gas transfer reaction (single stage WGS) is a necessary core technology. Suitable. First, in the case of WGS, a higher processing capacity is required than the existing two-stage WGS, and a large temperature change due to an exothermic reaction can occur, so that high performance of the catalyst and resistance to sintering are required. Recently, a platinum (Pt) -based catalyst for WGS and a copper (Cu) -based catalyst have been studied, but suffer from difficulties due to the high price of platinum and low low-temperature reactivity. Therefore, it is essential to develop a high-activity / high-endurance 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 with a copper-based catalyst, changed the composition ratio, production method, and cocatalyst of the catalyst and evaluated the reaction performance. A method for preparing a catalyst for water gas transfer reaction having high activity and stability at low temperature was developed to complete the present invention.

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 ageing 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 preparing a catalyst for a water-based gas transfer reaction with enhanced low-temperature reactivity suitable for a water-gas transfer reaction once exhibiting high activity and stability even at low temperatures.

In order to achieve the above object, the present invention

1) preparing a precursor aqueous solution by dissolving and heating a copper precursor, a zinc precursor, and an aluminum precursor;

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

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

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 dried precipitate 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 a catalyst for a water gas transfer reaction prepared according to the method as a single catalyst.

In the present invention, a copper-zinc-aluminum (Cu-Zn-Al) catalyst was prepared using a co-precipitation method, and the optimum composition ratio and optimum production method of the catalyst were derived to have high activity even at low temperatures and to improve catalyst stability. 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 usefully used as a catalyst for water gas transfer reaction.

1 is a diagram schematically illustrating a water gas transfer reaction device using a catalyst prepared according to an embodiment of the present invention.
2 is copper-zinc-aluminum (Cu-Zn-Al) prepared by fixing the composition ratio of copper (Cu): zinc (Zn) to 1: 1 and varying the aluminum (Al) content according to an embodiment of the present invention. It is a diagram showing the results of XRD analysis of the catalyst.
3 is a view showing the results of XRD analysis of a Cu-Zn-Al catalyst prepared by varying the Cu: Zn composition ratio according to an embodiment of the present invention.
4 is a view showing the results of TPR analysis of a Cu-Zn-Al catalyst prepared by fixing the Cu: Zn composition ratio at 1: 1 and changing the Al content according to an embodiment of the present invention.
5 is a view showing the results of TPR analysis of a Cu-Zn-Al catalyst prepared by varying the Cu: Zn composition ratio according to an embodiment of the present invention.
6 is a view showing the CO conversion of the Cu-Zn-Al catalyst prepared by fixing the Cu: Zn composition ratio to 1: 1 and changing the Al content according to an embodiment of the present invention.
7 is a view showing the CO conversion of Cu-Zn-Al catalyst prepared by varying the Cu: Zn composition ratio according to an embodiment of the present invention.
8 is a view showing the results of TPR analysis of a Cu-Zn-Al catalyst prepared by varying the proper sequence when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
9 is a view showing the CO conversion of the Cu-Zn-Al catalyst prepared by varying the proper sequence when preparing the Cu-Zn-Al catalyst according to an embodiment of the present invention.
10 is a view showing the results of TPR analysis of a Cu-Zn-Al catalyst prepared by varying the appropriate time when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
11 is a view showing the CO conversion of the Cu-Zn-Al catalyst prepared by varying the appropriate time when manufacturing the Cu-Zn-Al catalyst according to an embodiment of the present invention.
12 is a view showing the results of TPR analysis 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 view showing the CO conversion of the Cu-Zn-Al catalyst prepared by varying the appropriate pH when preparing the Cu-Zn-Al catalyst according to an embodiment of the present invention.
14 is a view showing the 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 view showing the CO conversion of the Cu-Zn-Al catalyst prepared by varying the aging temperature when preparing the Cu-Zn-Al catalyst according to an embodiment of the present invention.
16 is a diagram showing the TPR analysis results 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 view showing the CO conversion of the Cu-Zn-Al catalyst prepared by varying the aging time when preparing the Cu-Zn-Al catalyst according to an embodiment of the present invention.
18 is a view showing the TPR analysis results of the Cu-Zn-Al catalyst prepared by varying the firing temperature when preparing the Cu-Zn-Al catalyst according to an embodiment of the present invention.
19 is a view showing the CO conversion of Cu-Zn-Al catalyst prepared by varying the firing temperature when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
20 is a view showing the CO conversion rate over time of a Cu-Zn-Al catalyst prepared by varying the firing temperature when preparing a Cu-Zn-Al catalyst according to an embodiment of the present invention.
21 is a view showing the CO conversion of the Cu-Zn-Al catalyst prepared by adding a co-catalyst when preparing the Cu-Zn-Al catalyst according to an embodiment of the present invention.
22 is a diagram showing the CO conversion of Cu-Zn-Al catalyst and 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) preparing a precursor aqueous solution by dissolving and heating a copper precursor, a zinc precursor, and an aluminum precursor;

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

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

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 dried precipitate in step 4) at 250 to 450 ° C. for 4 to 8 hours.

In the present invention, the copper precursor, zinc precursor, and aluminum precursor in step 1) may be nitrate or nitrate hydrate, and specifically nitrate hydrate. For example, the copper precursors are copper nitrate (Cu (NO _{3) 3),} or copper nitrate hydrate may be a _{(Cu (NO 3) 3 ·} xH 2 O), 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 is not limited thereto.

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

In addition, the titration 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, i.e. immediately after titration It is most preferred to perform step 3).

In addition, the titration in step 2) may be titrated 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 titrate by adding a precipitant solution to the precursor aqueous solution.

In addition, the precipitating agent 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 precipitating agent may be added in an amount of 5 to 25% by weight relative to the total weight% of the precursor aqueous solution, more specifically 10 to 20% by weight, and more specifically 13 to 17% by weight And may be added in more specifically 15% by weight, but is not limited thereto.

In the present invention, it is preferable that the appropriate precursor aqueous solution in step 3) is aged at 20 to 90 ° C for 48 to 148 hours, more preferably at 35 to 85 ° C for 60 to 132 hours, and 37 to 83 It is more preferable to mature for 66 to 126 hours at ℃, more preferably for 72 to 120 hours at 40 to 80 ° C, and most preferably for 72 hours at 80 ° C. When the aging temperature is outside the above range, the catalytic activity may be lowered by reducing the reducing power of the catalyst at a low temperature. When the aging time is less than 48 hours, the reducing power of the catalyst may be reduced to degrade the catalytic activity. In addition, when the aging time exceeds 148 hours, the unit price may increase when preparing the catalyst, which may be economically inefficient.

In the present invention, the dried precipitate 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 Is more preferably calcined at 5 to 7 hours, more preferably calcined at 360 to 420 ° C for 5 to 7 hours, more preferably calcined at 390 to 410 ° C for 5 to 7 hours, It is more preferable to bake at 395 to 405 ° C for 5 to 7 hours, and most preferably to bake at 400 ° C for 6 hours. When the calcination temperature is out of the above range, all of Cu (OH) ₂ generated during precipitation of the precursor is not decomposed into CuO, so that the reducing power of the catalyst decreases and catalyst activity may deteriorate.

In the present invention, the catalyst for the 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%, and 45 to 65% by weight of copper based on the total weight of catalyst, It is even more preferable to include 25 to 45% by weight of zinc and 5 to 10% by weight of aluminum, comprising 65% by weight of copper, 25% by weight of zinc and 10% by weight of aluminum relative to the total weight of the catalyst. It is most preferred. When the aluminum content is less than 5% by weight, the reducing power of the catalyst may be lowered 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 preferably includes copper: zinc: aluminum in a weight ratio of 42.5 to 67.5: 22.5 to 47.5: 10, and more preferably 43 to 67: 23 to 45: 10 in a weight ratio. Preferably, it is more preferably included in a weight ratio of 44.5 to 65.5: 24.5 to 45.5: 10, more preferably 45 to 65: 25 to 45: 10, and more preferably 65: 25: 10 in weight ratio. It is most preferred to include. More specifically, the catalyst for the water gas transfer reaction preferably includes 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 preferably included in a weight ratio, and most preferably included in a weight ratio of 65:25:10. When the weight ratio of copper: zinc: aluminum is outside the above range, the reducing power of the catalyst may be lowered at low temperature.

In the present invention, it is preferable that the catalyst for the water gas transfer reaction does not contain a co-catalyst, such as platinum, magnesium or silicon. It is possible to obtain a catalyst exhibiting a superior conversion rate compared to a conventional commercial catalyst without using the co-catalyst, which has the advantage of being able to manufacture at a much lower cost than 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 exhibits a sufficiently high catalytic activity over the entire region temperature regardless of the high temperature reaction and low temperature reaction during the normal water gas transfer reaction. In addition, since it exhibits high stability and high durability, it is useful as a catalyst for water gas transfer reaction, and more specifically, once as a catalyst for water gas transfer reaction.

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

Specifically, the reactor prepared according to the production method of the present invention is filled in a reactor. A mixed gas filled with hydrogen, nitrogen, methane, carbon monoxide and carbon dioxide is passed through the reactor. Subsequently, water vapor is supplied at a predetermined ratio with the concentration of methane, carbon monoxide, and carbon dioxide in the reaction gas. Supply of the water vapor may be made using a pump, for example, a syringe pump (syringe pump) or a precision flow control pump (metering pump). The temperature control of water vapor can be controlled by installing a pre-heater on the top of the reaction gas injection section of the reactor, and the temperature can be controlled by a heating system using PID control. Thereafter, a water gas transfer reaction is performed. In performing the water gas transfer reaction process, the reaction temperature in the presence of the catalyst 150 ~ 400 ℃, more specifically 200 ~ 300 ℃, the hourly space velocity of the gas (GHSV) 8,001 ~ 36,050h ^-1 It can be carried out under the conditions of. Polymer fuel cells (PEMFC) for fuel cells for water gas transfer reactions, and hydrogen stations or ammonia synthesis processes, can be usefully used in petrochemical processes.

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 copper, 25% by weight zinc, and 10% by weight aluminum was prepared using a coprecipitation method.

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 Furnace Al (NO ₃ ) ₃ · 9H ₂ O (99%, Aldrich) 2.25 g was dissolved in 0.5 L of distilled water and heated to 80 ° C. Then, a 15 wt% potassium hydroxide (KOH) solution, which is a precipitating agent, was added in a constant temperature state, the pH value was adjusted to 10, titrated, and aged at 80 ° C for 3 days. It was washed several times with distilled water to remove K ⁺ ions remaining in the aged solution. The precipitate obtained after washing was dried at 110 ° C. and 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) was used to examine the crystallinity and composition of the prepared copper-zinc-aluminum catalyst using Rigaku D / MAX-IIIC equipment, and measured at CuK radiation, 40 kV, 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 is about 0.1 g to 0.2 g, and the pre-treatment was performed at 110 ° C. under a vacuum of 0.5 mmHg for 12 hours.

<2-3> TPR  analysis

The 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 in the process of heating up to 400 ° C. (heating rate: 10 ° C./min) in a 10% H ₂ / Ar atmosphere, the reduction characteristics of the catalyst according to the temperature change were analyzed to obtain TPR analysis results.

<2-4> N ₂ O - chemisorption  analysis

The N ₂ O-chemisorption analysis of the prepared copper-zinc-aluminum catalyst was measured by N ₂ O surface titration using Autochem 2920 (Micromeritics Co.). Prior to 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 emissions were measured while maintaining 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 / m ² was assumed. Cu particle size was calculated using the formula 6000 / (8.92 × Cu metal surface area / Cu fraction in gram catalyst).

< Example  3> Analysis of water gas transfer reaction using catalyst

<3-1> Manufacture of water gas transfer reaction device

A water-gas transfer reaction (WGS) reaction apparatus using a copper-zinc-aluminum catalyst prepared as a 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, It consists of Micro-Gc (70). Reaction gas is introduced into the MFC (10). The reaction gas flow rate was precisely adjusted using a 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 portion of the quartz tube 40 and supplies H ₂ O required for the WGS reaction in water vapor. The pre-heater was manufactured by attaching a heating wire to a 1/4 "stainless steel tube, and the temperature was measured by installing a thermocouple at the middle. H ₂ O was started to be injected after the catalytic reduction was completed, and the pre- The heater was operated to adjust to maintain about 180 ° C. The syringe pump 30 is located between the MFC and the pre-heater to supply H ₂ O necessary for the WGS reaction Fill the 50 ml syringe with distilled water and then use the 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 0.20 ml / h to 426 ml / h The temperature of the reactor was controlled by mounting the quartz tube 40 in the furnace 50. The quartz tube 40 used 1/4 ”. Quartz material is inserted in the middle of the tube to prevent channeling and pressure drop. A catalyst with a size of 60 mesh to 100 mesh was used in order to measure the temperature of the catalyst layer inside the quartz tube, and a thermocouple was installed at the middle of the catalyst layer. The cooler 60 passes the gas after the reaction and removes the remaining H ₂ O after the WGS reaction The temperature of the cooler was maintained at 2.2 ° C. and accurately controlled by a digital PID controller JSCR-13C model (JSR) The temperature control range was from -45 ° C to 120 ° C The cooling water used in the cooler was prepared by mixing ethylene glycol and water Micro-GC (70) analyzes the composition and proportion of the gas after the WGS reaction. Agilent 3000A Micro-GC (agilent technologies) was used, Channel 1 of Micro-GC was equipped with a Molecular sieve column for H ₂ , N ₂ , CO, and CH ₄ gas analysis, and Channel 2 was analyzed for CO ₂ gas For p A lot-U column was fitted.

<3-2> Water gas transfer reaction using catalyst

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 performed in a temperature range of 200 ° C to 240 ° C. The catalyst was injected 0.109 g, and a thermocouple was installed in the catalyst layer to measure the actual reaction temperature. Before proceeding to the catalytic reaction, the temperature was raised to 200 ° C with a temperature increase rate of 3.3 ° C / min in a 2% H ₂ / N ₂ atmosphere, followed by a reduction process for 1 hour. After the reduction was completed, a 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 was generated while passing through a pre-heater (180 ° C) before the catalytic reaction. After the reaction, the gas was removed by using a cooler. After the moisture was finally removed, the gas was analyzed using an on-line micro-gas chromatograph (Agilent 3000A). The CO conversion was calculated by applying the concentration of the exhaust gas after the WGS reaction to [Equation 1] below.

[Equation 1]

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

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

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

To find out the copper-zinc-aluminum catalyst activity according to the copper, zinc and aluminum content, after preparing copper-zinc-aluminum catalysts with different copper, zinc and aluminum composition ratios, XRD analysis, BET analysis, TPR analysis and WGS reaction Analysis was performed.

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 Cu 40 wt% / Zn 40 wt% / Al 20 wt% 3 Cu 42.5 wt% / Zn 42.5 wt% / Al 15 wt% 4 Cu 45 wt% / Zn 45 wt% / Al 10 wt% 5 Cu 47.5 wt% / Zn 47.5 wt% / Al 5 wt% 6 Cu 50 wt% / Zn 50 wt% / Al 0 wt% 7 Cu 50 wt% / Zn 40 wt% / Al 10 wt% 8 Cu 60 wt% / Zn 30 wt% / Al 10 wt% 9 Cu 65 wt% / Zn 25 wt% / Al 10 wt% 10 Cu 70 wt% / Zn 20 wt% / Al 10 wt%

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 FIG. 2 and FIG. 3, XRD analysis confirmed that as the Al content of the copper-zinc-aluminum catalyst increased, the intensity of the CuO and ZnO peaks decreased (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, as a result of BET analysis, it was confirmed that in the case of the catalyst without Al added (Sample 6), the catalyst surface area was the lowest, while the BET surface area of the catalyst increased with the addition of Al. In particular, it was confirmed that when the Al content was increased from 5% to 20% by weight, the surface area of the catalyst was also increased, but when it was increased from 20% to 30% by weight, the surface area of the catalyst was 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. On the other hand, 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 the Sample 9 catalyst exhibited the lowest Cu crystal size at 12.3 nm (Table 2).

In addition, as shown in FIGS. 4 and 5, in the case of a catalyst without Al added (Sample 6), a reduction peak was exhibited at a higher temperature than catalysts with Al added, confirming that the reduction power was enhanced 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 moves to a higher temperature as the copper: zinc composition ratio increases. In the case of the sample 9 catalyst, it was confirmed that the reduction peak appeared at the lowest temperature and had the highest reduction power (FIG. 5).

In addition, as shown in Table 3, as the result of 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, while the Al content is from 10% by weight to 30% by weight. It was confirmed that the number of Cu atoms on the surface decreased when it increased. In order to obtain high catalytic activity, the number of Cu atoms dispersed on the surface has to be high, so it was confirmed that the catalyst exhibits high catalytic activity when the Al content is 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 surface Cu atom number of the sample 9 catalyst was the highest.

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

Therefore, it was confirmed that the copper-zinc-aluminum catalyst is suitable as a catalyst for the water gas transfer reaction once the results are summarized. In addition, it was confirmed that the optimum aluminum content range is 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, and among these, 65:25:10 shows the best catalytic activity. Was confirmed.

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

TPR analysis and WGS after preparing the catalyst by changing the titration sequence, titration time, titration pH, maturation temperature, maturation time, and firing temperature in order to investigate the effect of the manufacturing method on the catalyst performance when preparing the copper-zinc-aluminum catalyst Reaction analysis was performed.

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

In order to investigate 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 varying the titration sequence.

Specifically, <Example 1> and except that the copper precursor, zinc precursor, and aluminum precursor aqueous solution heated in a 15 wt% potassium hydroxide (KOH) solution, which is a precipitant in a constant temperature state, is added and titrated by adjusting the pH value to 10. In the same way, a catalyst (Cu-Zn-Al reverse) was prepared. Then, for the catalyst (Cu-Zn-Al reverse) prepared in the above and the catalyst (Cu-Zn-Al normal) prepared in the <Example 1>, 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 has 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 WGS reaction analysis, it was confirmed that the Cu-Zn-Al normal catalyst exhibits 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 in preparing the copper-zinc-aluminum catalyst by coprecipitation is a method of administering a precipitant to the precursor aqueous solution.

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

In order to investigate the effect of the titration time on the catalyst performance during the preparation of the copper-zinc-aluminum catalyst, TPR analysis and WGS reaction analysis were performed after preparing the catalyst by varying the titration time.

Specifically, the catalyst was prepared in the same manner as in <Example 1>, except that a 15 wt% potassium hydroxide (KOH) solution, which is a precipitant in a constant temperature state, was added and the pH value was adjusted to 10 and titrated for 0, 30 or 60 minutes. It was prepared. Then, for each of the catalysts prepared above, TPR analysis was performed in the same manner as 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 FIG. 10 and FIG. 11, the TPR analysis confirmed that the catalyst having a titration time of 0 minutes has the highest reducing power due to the reduction of CuO species at the lowest temperature (FIG. 10). In addition, as a result of WGS reaction analysis, it was confirmed that the catalyst having a proper 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 is 0 minutes when the copper-zinc-aluminum catalyst is prepared by coprecipitation.

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

In order to investigate the effect of the proper pH on the catalyst performance when preparing the copper-zinc-aluminum catalyst, the catalyst was prepared by varying the proper pH, 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 a 15 wt% potassium hydroxide (KOH) solution, which is a precipitating agent, was added in a constant temperature state and titrated by adjusting the pH value to 9.5, 10, 10.5 or 11. Did. Then, for each of the catalysts prepared above, TPR analysis was performed in the same manner as 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 FIG. 12 and FIG. 13, as a result of TPR analysis, it was confirmed that when the proper pH is increased from 9.5 to 10, the reduction peak moves to a low temperature to improve the reducing power of the catalyst. On the other hand, when the pH was increased from 10 to 11, it was confirmed that the reduction power of the catalyst was reduced by moving the reduction peak to high temperature (FIG. 12). In addition, it was confirmed that when the proper pH is 10 and 10.5, it shows high catalytic activity in all temperature regions (FIG. 13).

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

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

In order to investigate 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 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 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, a TPR analysis result shows that a reduction peak appears in a temperature region lower than the case where the aging temperature is 20 ° C or 90 ° C when the aging temperature is 40 ° C, 60 ° C, or 80 ° C. It was confirmed that the reducing power was enhanced (FIG. 14). In addition, it was confirmed that when the aging temperature is 40 ° C, 60 ° C or 80 ° C, it shows high catalytic activity, and when the aging temperature is 80 ° C, it shows the highest catalytic activity (FIG. 15).

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

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

In order to investigate the effect of the aging 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 aging time.

Specifically, a catalyst was prepared in the same manner as in <Example 1>, except that the aging time at the time of aging was 8, 48, 72 or 120 hours. Then, for each of the catalysts prepared above, TPR analysis was performed in the same manner as 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 FIG. 16 and FIG. 17, as a result of TPR analysis, it was confirmed that the reduction power of the catalyst was enhanced by moving the temperature of the reduction peak to a low temperature as the aging time increased (FIG. 16). In addition, it was confirmed that when the aging time is 72 hours or more, it shows high catalytic activity in all temperature regions. In addition, it was confirmed that the CO conversion rate at 220 ° C. or higher reached the equilibrium conversion rate (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 coprecipitation.

<2-6> At firing temperature  Catalyst activity

In order to investigate the effect of the firing temperature on the catalyst performance when preparing the copper-zinc-aluminum catalyst, a catalyst was prepared by varying the firing 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 at firing was changed to 250, 400 or 450 ° C. Then, for each of the catalysts prepared above, TPR analysis was performed in the same manner as 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, TPR analysis confirmed that the reduction peak temperature of the catalyst fired at 250 ° C was the lowest. However, it was confirmed to show a small active peak (Fig. 18). In addition, as a result of WGS reaction analysis, it was confirmed that the firing temperature was 250 ° C or 400 ° C, indicating high catalytic activity (FIG. 19). In addition, as a result of the catalyst stability test, the catalyst fired at 250 ° C. showed stable catalyst activity for 100 hours, after which it was confirmed that the catalyst activity gradually decreased. On the other hand, it was confirmed that the catalyst calcined at 400 ° C. showed very stable activity without significant activity reduction for 200 hours (FIG. 20).

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

Therefore, when the copper-zinc-aluminum catalyst is prepared by coprecipitation through the results of Experimental Examples <2-1> to <2-6>, a method of introducing a precipitant into the precursor aqueous solution as a titration method, titration time is 0 minutes, titration When the pH was 10 to 10.5, the aging temperature was 40 to 80 ° C, the aging time was 72 to 120 hours, and the sintering temperature was 400 ° C, it was confirmed that it exhibits excellent catalytic activity as a catalyst for water gas transfer reaction.

< Experimental example  3> In copper-zinc-aluminum catalyst Co-catalyst  Confirmation of catalyst activity by addition

In order to investigate the effect of the addition of a co-catalyst on the catalyst performance during the preparation of the copper-zinc-aluminum catalyst, a catalyst was prepared by adding the co-catalyst during the catalyst preparation, and then TPR analysis and WGS reaction analysis were performed.

Specifically, prepared in the same manner as described in <Example 1>, but when preparing a precursor mixed solution, Cu (NO ₃ ) ₃ · x H ₂ O (99%, Aldrich) 4.60 g as a copper precursor, Zn as a zinc precursor (NO ₃ ) ₂ · 6H ₂ O (99%, Aldrich) 2.57 g, aluminum precursor Al (NO ₃ ) ₃ · 9H ₂ O (99%, Aldrich) 2.25 g, co-catalyst precursor Pt (NH ₃ ) ₄ (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 in <Example 3>.

As a result, as shown in Fig. 21, it was confirmed that the Cu-Zn-Al catalyst without the addition of a co-catalyst showed a high catalytic activity of 80% or more in all temperature regions (Fig. 21).

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

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

Specifically, WGS analysis was performed on each of the catalyst prepared in the optimum condition in <Example 1> and the commercial catalyst MDC-7. At this time, the 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 commercially available product for Clariant's water gas transfer reaction.

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

Claims (11)

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

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