A catalyst for deep oxidation removal of hydrocarbons in crude carbon dioxide and its preparation method

Abstract

The present invention provides a catalyst for deep oxidation removal of hydrocarbons in crude carbon dioxide and a preparation method thereof, and relates to the field of catalytic technology. The hydrocarbon oxidation catalyst provided by the present invention comprises a reducible oxide carrier and an active component, wherein the active component is one or more of Pd, Pt, Ni, Fe, Rh and Ru; the reducible oxide carrier is an oxide composed of one or more elements of +4-valent Ce, +4-valent Ti, +4-valent Zr, +3-valent Eu and +3-valent Y. The present invention utilizes reducible oxides to load active components to achieve the synergistic catalytic effect of metal active components and carriers. The metal can activate hydrocarbons, and the reducible carrier activates oxygen molecules, so that the catalyst has excellent ability to deeply oxidize and remove hydrocarbons, and can purify the hydrocarbon content in carbon dioxide to below 1ppm at a relatively low temperature (50-500°C).

Description

Technical Field

[0001] The present invention relates to the field of catalytic technology, and in particular to a catalyst for deep oxidation removal of hydrocarbons in crude carbon dioxide and a preparation method thereof. Background Art

[0002] In the field of semiconductor manufacturing, electronic grade (high purity) carbon dioxide is used for oxidation, diffusion, chemical vapor deposition, supercritical cleaning gas and other processes. With the rapid development of the semiconductor industry, the domestic demand for electronic grade carbon dioxide (99.999%) has also continued to increase. Industrial crude carbon dioxide mainly contains CH4, C2H6, C3H8 and a small amount of carbon four hydrocarbons and impurities such as oxygen, water, sulfur and phosphorus. The catalytic oxidation method is used to remove trace hydrocarbon impurities. It has the characteristics of high purification depth and no secondary impurities. It can effectively reduce the energy consumption of hydrocarbon separation and is a powerful means to produce electronic grade carbon dioxide. CH4 has high stability among hydrocarbon impurities and is the most difficult component to activate and remove. At present, the commonly used in literature reports is the supported Pd-based precious metal catalyst, and the carrier uses the relatively inert Al2O3. The activation of hydrocarbons and oxygen molecules is carried out on the metal, resulting in a high temperature (≥350℃) required for hydrocarbon oxidation. Summary of the invention

[0003] The object of the present invention is to provide a catalyst for deep oxidation removal of hydrocarbons in crude carbon dioxide and a preparation method thereof. The catalyst provided by the present invention can achieve deep oxidation removal of hydrocarbons in carbon dioxide at a relatively low temperature.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a hydrocarbon oxidation catalyst, comprising a reducible oxide carrier and an active component, wherein the active component is one or more of Pd, Pt, Ni, Fe, Rh and Ru; the reducible oxide carrier is an oxide composed of one or more elements selected from +4-valent Ce, +4-valent Ti, +4-valent Zr, +3-valent Eu and +3-valent Y.

[0006] Preferably, the reducible oxide carrier is CeO2, TiO2 or Ce 0.5 Zr 0.5 O2.

[0007] Preferably, the active component is Pd.

[0008] Preferably, the content of active components in the hydrocarbon catalyst is 0.1 to 5 wt.%.

[0009] The present invention provides a method for preparing the hydrocarbon oxidation catalyst described in the above scheme, comprising the following steps:

[0010] A reducible oxide carrier, a solvent and an active component precursor are mixed to obtain a mixed liquid; the active component precursor is one or more of a Pd precursor, a Pt precursor, a Ni precursor, a Fe precursor, a Rh precursor and a Ru precursor;

[0011] The mixed liquid is sequentially dried and calcined to obtain a catalyst precursor;

[0012] The catalyst precursor is subjected to a reduction reaction under a reducing atmosphere to obtain the hydrocarbon oxide catalyst.

[0013] Preferably, the calcination is carried out in an air atmosphere; the calcination temperature is 400-900° C., and the insulation time is 3-6 hours.

[0014] Preferably, the gas providing the reducing atmosphere comprises hydrogen and / or carbon monoxide.

[0015] Preferably, the reduction reaction temperature is 100-300° C. and the time is 0.5-2 h.

[0016] Preferably, the solvent includes one or more of water, ethanol, methanol, glacial acetic acid, n-hexane, cyclohexane and toluene.

[0017] The present invention provides the use of the hydrocarbon oxidation catalyst described in the above scheme or the hydrocarbon oxidation catalyst prepared by the preparation method described in the above scheme in oxidative removal of hydrocarbon substances in crude carbon dioxide; the reaction temperature is 50-500°C.

[0018] The present invention provides a hydrocarbon oxidation catalyst, comprising a reducible oxide carrier and an active component, wherein the active component is one or more of Pd, Pt, Ni, Fe, Rh and Ru; the reducible oxide carrier is an oxide composed of one or more elements of +4-valent Ce, +4-valent Ti, +4-valent Zr, +3-valent Eu and +3-valent Y. The present invention uses the reducible oxide to load the active component to achieve the synergistic catalytic effect of the metal active component and the carrier, the metal can activate hydrocarbons, and the reducible carrier activates oxygen molecules, so that the catalyst has excellent ability to deeply oxidize and remove hydrocarbons, and can purify the hydrocarbon content in carbon dioxide to less than 1ppm at a relatively low temperature (50 to 500°C).

[0019] In addition, the catalyst of the present invention has good structural stability, and is not prone to site sintering and loss during the reaction process, and the operation of the catalyst is stable.

[0020] The invention provides a method for preparing the hydrocarbon oxidation catalyst, which has a simple and easy preparation process, good repeatability and is easy to scale up for production. DETAILED DESCRIPTION

[0021] The present invention provides a hydrocarbon oxidation catalyst, comprising a reducible oxide carrier and an active component, wherein the active component is one or more of Pd, Pt, Ni, Fe, Rh and Ru; the reducible oxide carrier is an oxide composed of one or more elements selected from +4-valent Ce, +4-valent Ti, +4-valent Zr, +3-valent Eu and +3-valent Y.

[0022] In the present invention, the active component is preferably Pd. The content of the active component in the hydrocarbon catalyst is preferably 0.1 to 5 wt.%, more preferably 0.5 to 4 wt.%, and further preferably 1 to 3 wt.%.

[0023] In the present invention, the reducible oxide carrier is preferably CeO2, TiO2 or Ce 0.5 Zr 0.5 O2.

[0024] The present invention utilizes reducible oxides to load active components to achieve the synergistic catalytic effect of metal active components and carriers. The metal can activate hydrocarbons, and the reducible carrier activates oxygen molecules, so that the catalyst has excellent ability to deeply oxidize and remove hydrocarbons, and can purify the hydrocarbon content in carbon dioxide to below 1 ppm at a relatively low temperature (50-500°C).

[0025] The present invention provides a method for preparing the hydrocarbon oxidation catalyst described in the above scheme, comprising the following steps:

[0026] A reducible oxide carrier, a solvent and an active component precursor are mixed to obtain a mixed liquid; the active component precursor is one or more of a Pd precursor, a Pt precursor, a Ni precursor, a Fe precursor, a Rh precursor and a Ru precursor;

[0027] The mixed liquid is sequentially dried and calcined to obtain a catalyst precursor;

[0028] The catalyst precursor is subjected to a reduction reaction under a reducing atmosphere to obtain the hydrocarbon oxide catalyst.

[0029] In the present invention, the reducible oxide carrier is preferably prepared by itself; the preparation method of the reducible oxide carrier preferably comprises the following steps:

[0030] The metal source corresponding to the metal element in the reducible oxide carrier is dissolved in solvent A to obtain a dissolving solution; a precipitant is added to the dissolving solution to perform a precipitation reaction, solid-liquid separation is performed, the obtained precipitate is dried, and the dried product is calcined in an air atmosphere to obtain a reducible oxide carrier.

[0031] In the present invention, when the metal source includes a Ce source, the Ce source is preferably any one of cerium chloride, cerium sulfate, cerous sulfate, cerium nitrate, cerium oxalate, cerium acetate and ammonium cerium nitrate or a combination thereof; when the metal source includes a Ti source, a Zr source, a Eu source or a Y source, the metal source is preferably one of chlorides, hydroxides, nitrates, sulfates and carbonates of the corresponding metal (Ti, Zr, Eu or Y) or a combination thereof.

[0032] In the present invention, the solvent A preferably includes one or more of water, ethanol, methanol, glacial acetic acid, n-hexane, cyclohexane and toluene. The present invention preferably selects a suitable solvent according to the type of the metal source to ensure that the metal source can be dissolved. The present invention has no special requirements for the amount of the solvent A, as long as it can completely dissolve the metal source.

[0033] In the present invention, the precipitant preferably includes one or more of sodium hydroxide, potassium hydroxide, urea, ammonia water, ammonium carbonate and ammonium bicarbonate. The present invention does not specifically limit the amount of the precipitant, as long as it can form a precipitate.

[0034] In the present invention, the temperature of the precipitation reaction is preferably 50 to 90° C., and the time is preferably 1 to 12 hours. In the present invention, the precipitation reaction is preferably carried out under stirring conditions.

[0035] The present invention has no special requirements for the solid-liquid separation method, and any method known in the art that can achieve solid-liquid separation can be used, such as centrifugation.

[0036] After the precipitate is obtained, the present invention preferably washes it multiple times with deionized water and anhydrous ethanol, and then dries it.

[0037] In the present invention, the drying temperature is preferably 60 to 120° C., more preferably 70 to 100° C.; the drying time is preferably 6 to 12 hours, more preferably 8 to 10 hours.

[0038] In the present invention, the calcination temperature is preferably 400-900° C., more preferably 500-800° C.; the holding time is preferably 3-6 hours, more preferably 4-6 hours.

[0039] After obtaining the reducible oxide carrier, the present invention mixes the reducible oxide carrier, a solvent and an active component precursor to obtain a mixed liquid.

[0040] In the present invention, the solvent preferably includes one or more of water, ethanol, methanol, glacial acetic acid, n-hexane, cyclohexane and toluene. In the present invention, the solvent can dissolve the active component precursor without dissolving the reducible oxide carrier, and those skilled in the art can select a suitable solvent type within the above range accordingly. The present invention has no special requirements for the amount of the solvent, as long as the reducible oxide carrier can be evenly dispersed and the active component precursor can be completely dissolved.

[0041] In the present invention, the active component precursor is one or more of a Pd precursor, a Pt precursor, a Ni precursor, a Fe precursor, a Rh precursor and a Ru precursor; the Pd precursor is preferably one or a combination of palladium chloride, palladium acetylacetonate, palladium nitrate, palladium acetate, ammonium tetrachloropalladate and sodium tetrachloropalladate; the Pt precursor is preferably one or a combination of platinum chloride, tetraammine platinum nitrate, platinum acetylacetonate and ammonium chloroplatinate; the Ni precursor is preferably one or a combination of nickel nitrate, nickel chloride, nickel sulfate and nickel acetylacetonate; the Fe precursor is preferably one or a combination of ferric nitrate, ferric chloride, ferric sulfate, ferrous sulfate and ferric acetate; the Rh precursor is preferably one or a combination of rhodium chloride, rhodium triacetylacetonate and rhodium nitrate; the Ru precursor is preferably one or a combination of ruthenium chloride, ruthenium acetylacetonate, ruthenium nitrate and ruthenium acetate. In the present invention, the amount of the active component precursor is determined according to the content of the active component in the final catalyst, and the content of the active component in the hydrocarbon catalyst is 0.1 to 5 wt.%.

[0042] In the present invention, mixing the reducible oxide carrier, solvent and active component precursor preferably includes: dispersing the reducible oxide carrier in the solvent by ultrasound, then adding the active component precursor and stirring continuously at 50-100° C. for 1-6 hours to obtain a mixed liquid.

[0043] After obtaining the mixed liquid, the present invention sequentially dries and calcines the mixed liquid to obtain a catalyst precursor. In the present invention, the drying temperature is preferably 60 to 120° C., and the drying time is preferably 6 to 12 hours.

[0044] In the present invention, the calcination is preferably carried out in an air atmosphere; the calcination temperature is preferably 400-900°C, more preferably 500-800°C, and further preferably 600-700°C; the holding time is preferably 3-6h, more preferably 4-5h. The purpose of the calcination in the present invention is to decompose the active component precursor into oxides and to decompose and remove anions in the precursor.

[0045] After obtaining the catalyst precursor, the present invention performs a reduction reaction on the catalyst precursor under a reducing atmosphere to obtain the hydrocarbon oxide catalyst.

[0046] In the present invention, the gas providing the reducing atmosphere preferably includes hydrogen and / or carbon monoxide. In the present invention, the temperature of the reduction reaction is preferably 100 to 300°C, more preferably 150 to 250°C; the holding time of the reduction reaction is preferably 0.5 to 2 hours, more preferably 1 to 1.5 hours. After the reduction reaction, the oxide of the active component is reduced to a metal element.

[0047] The present invention provides the use of the hydrocarbon oxidation catalyst described in the above scheme or the hydrocarbon oxidation catalyst prepared by the preparation method described in the above scheme in oxidative removal of hydrocarbon substances in crude carbon dioxide; the reaction temperature is 50-500°C.

[0048] In the present invention, the oxidation removal of hydrocarbons in crude carbon dioxide is preferably carried out in a fixed bed reactor, and the reaction conditions preferably include: the reaction pressure is 0.1-0.3 MPa, more preferably 0.15-0.25 MPa; the total content of hydrocarbons in the feed gas is 10-500 ppm (in terms of methane), more preferably 50-400 ppm (in terms of methane), and further preferably 100-200 ppm (in terms of methane); the volume space velocity of the reaction is 5000-20000 h -1 , more preferably 8000 to 16000 hours -1 , more preferably 10 to 14000h -1 .

[0049] As a preferred embodiment, the reaction temperature is 100 to 450°C, more preferably 200 to 350°C.

[0050] The hydrocarbon oxidation catalyst provided by the present invention, its preparation method and application are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0051] Comparative Example 1

[0052] The catalyst is metal Pd particles supported by Al2O3 carrier, and the preparation method is as follows: 1g of commercial Al2O3 powder is placed in 60mL of deionized water and ultrasonicated for 30min, 16.8mg of palladium chloride is added to the above solution, the solution is stirred at 60°C for 2h, and then placed in an oven and dried at 60°C for 12h, and the obtained powder is calcined at 400°C in air for 3h to obtain a catalyst precursor. The catalyst precursor is reduced at 200°C for 1h under hydrogen conditions to obtain a supported Pd / Al2O3 catalyst, and the mass fraction of Pd is 1wt.%.

[0053] Comparative Example 2

[0054] The catalyst is metal Pd particles supported by SiO2 carrier, and the preparation method is as follows: 1g of commercial SiO2 powder is placed in 60mL of deionized water and ultrasonicated for 30min, 16.8mg of palladium chloride is added to the above solution, the solution is stirred at 60°C for 3h, and then placed in an oven and dried at 60°C for 12h, and the obtained powder is calcined at 400°C in air for 3h to obtain a catalyst precursor. The catalyst precursor is reduced at 200°C for 1h under hydrogen conditions to obtain a supported Pd / SiO2 catalyst, and the mass fraction of Pd is 1wt.%.

[0055] Comparative Example 3

[0056] The catalyst is metal Pd particles supported on a MgO carrier, and the preparation method is as follows: 1g of commercial MgO powder is placed in 60mL of deionized water and ultrasonicated for 30min, 16.8mg of palladium chloride is added to the above solution, the solution is stirred at 60°C for 3h, and then placed in an oven and dried at 60°C for 12h, and the obtained powder is calcined at 400°C in air for 3h to obtain a catalyst precursor. The catalyst precursor is reduced at 200°C for 1h under hydrogen conditions to obtain a supported Pd / MgO catalyst, and the mass fraction of Pd is 1wt.%.

[0057] Example 1

[0058] The catalyst is metal Pd particles supported by CeO2 carrier, and the preparation method is as follows:

[0059] 4.34 g of Ce(NO3)3·6H2O was dissolved in 150 mL of deionized water to prepare a uniform solution, and then 2.40 g of (NH4)2CO3 was added to the solution and stirred continuously at 80°C for 4 h. The treated slurry was placed in an oven at 60°C and dried for 12 h. The dried sample was calcined in air at 500°C for 6 h to obtain a CeO2 carrier.

[0060] 1g of the prepared CeO2 powder was weighed and placed in 60mL of deionized water and ultrasonicated for 30min. 16.8mg of palladium chloride was added to the above solution. After the solution was stirred at 60℃ for 3h, it was placed in an oven and dried at 60℃ for 12h. The obtained powder was calcined at 400℃ in air for 3h to obtain a catalyst precursor. The catalyst precursor was reduced at 200℃ for 1h under hydrogen conditions to obtain a supported Pd / CeO2 catalyst with a mass fraction of Pd of 1wt.%.

[0061] Example 2

[0062] The catalyst is Ce 0.5 Zr 0.5 The preparation method of the metal Pd particles supported by O2 carrier is as follows:

[0063] 2.17 g of Ce(NO3)3·6H2O and 2.15 g of Zr(NO3)4·5H2O were dissolved in 150 mL of deionized water to prepare a uniform solution. 2.40 g of (NH4)2CO3 was added to the solution and stirred continuously at 80°C for 4 h. The treated slurry was placed in an oven at 60°C and dried for 12 h. The dried sample was calcined in air at 500°C for 6 h to obtain Ce 0.5 Zr 0.5 O2 carrier.

[0064] Weigh 1 g of prepared Ce 0.5 Zr 0.5 O2 powder was placed in 60 mL of deionized water and ultrasonicated for 30 min. 16.8 mg of palladium chloride was added to the above solution. After the solution was stirred at 60 ° C for 3 h, it was placed in an oven and dried at 60 ° C for 12 h. The obtained powder was calcined at 400 ° C in air for 3 h to obtain a catalyst precursor. The catalyst precursor was reduced at 200 ° C for 1 h under hydrogen conditions to obtain a supported Pd / Ce 0.5 Zr 0.5 O2 catalyst, Pd mass fraction is 1wt.%.

[0065] Example 3

[0066] The catalyst is metal Pd particles supported by TiO2 carrier, and the preparation method is as follows:

[0067] 3.79 g of TiCl4 was dissolved in 150 mL of anhydrous ethanol solution to prepare a uniform solution, and then 2.40 g of (NH4)2CO3 was added to the solution and stirred continuously at 80°C for 4 h. The treated slurry was placed in an oven at 60°C and dried for 12 h. The dried sample was calcined in air at 500°C for 6 h to obtain a TiO2 carrier.

[0068] 1g of the prepared TiO2 powder was weighed and placed in 60mL of deionized water and ultrasonicated for 30min. 16.8mg of palladium chloride was added to the above solution. After the solution was stirred at 60℃ for 3h, it was placed in an oven and dried at 60℃ for 12h. The obtained powder was calcined at 400℃ in air for 3h to obtain a catalyst precursor. The catalyst precursor was reduced at 200℃ for 1h under hydrogen conditions to obtain a supported Pd / TiO2 catalyst with a mass fraction of Pd of 1wt.%.

[0069] Example 4

[0070] The catalyst is Ce 0.5 Zr 0.5 The preparation method of metal Pt particles supported by O2 carrier is as follows:

[0071] 2.17 g of Ce(NO3)3·6H2O and 2.15 g of Zr(NO3)4·5H2O were dissolved in 150 mL of deionized water to prepare a uniform solution. 2.40 g of (NH4)2CO3 was added to the solution and stirred continuously at 80°C for 4 h. The treated slurry was placed in an oven at 60°C and dried for 12 h. The dried sample was calcined in air at 500°C for 6 h to obtain Ce 0.5 Zr 0.5 O2 carrier.

[0072] Weigh 1 g of prepared Ce 0.5 Zr 0.5 O2 powder was placed in 60 mL of deionized water and ultrasonicated for 30 min. 17.3 mg of platinum tetrachloride was added to the above solution. After the solution was stirred at 60 ° C for 3 h, it was placed in an oven and dried at 60 ° C for 12 h. The obtained powder was calcined at 400 ° C in air for 3 h to obtain a catalyst precursor. The catalyst precursor was reduced at 300 ° C for 1 h under hydrogen conditions to obtain a supported Pt / Ce 0.5 Zr 0.5 O2 catalyst, mass fraction of Pt is 1wt.%.

[0073] The catalysts of Comparative Examples 1 to 3 and Examples 1 to 4 were used to carry out the removal of hydrocarbons from high-concentration carbon dioxide. The specific activity evaluation experimental process is as follows: The activity of the catalyst was tested using a fixed bed reactor. 100 mg of the catalyst was weighed and placed in the constant temperature section of the reactor. Both ends of the catalyst were fixed with quartz wool. The reaction raw gas contained 30 ppm of CH4 impurities, the total gas flow rate was 50 mL / min, and the volume space velocity was 6000 h -1 , the reaction temperatures are 350°C and 290°C, and the reaction absolute pressure is 120 kPa.

[0074] The results of selective hydrogenation of acetylene using the catalysts of Comparative Examples 1 to 3 and Examples 1 to 4 are shown in Table 1 below:

[0075] Table 1 Hydrocarbon removal activity of each catalyst

[0076]

[0077]

[0078] It can be seen from Table 1 that, compared with the comparative catalyst, under low temperature (≤350°C) conditions, the activity of the Pd-based catalyst supported on the reducible oxide carrier in the embodiment of the present invention is significantly improved, and under the condition that the raw gas contains low concentrations of hydrocarbons, deep removal of hydrocarbon impurities can be achieved.

[0079] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. Use of a hydrocarbon oxidation catalyst in oxidative removal of hydrocarbons from crude carbon dioxide, characterized in that: The reaction temperature is 50-500°C; The hydrocarbon oxidation catalyst comprises a reducible oxide carrier and an active component, wherein the active component is Pd; the reducible oxide carrier is CeO2, TiO2 or Ce 0.5 Zr 0.5 O2; the content of active components in the hydrocarbon oxidation catalyst is 0.1 to 5 wt.%.

2. The use according to claim 1, characterized in that: The preparation method of the hydrocarbon oxidation catalyst comprises the following steps: The reducible oxide carrier, the solvent and the active component precursor are mixed to obtain a mixed liquid; the active component precursor is a Pd precursor; The mixed liquid is sequentially dried and calcined to obtain a catalyst precursor; The catalyst precursor is subjected to a reduction reaction under a reducing atmosphere to obtain the hydrocarbon oxidation catalyst.

3. The use according to claim 2, characterized in that: The calcination is carried out in an air atmosphere; the calcination temperature is 400-900° C., and the heat preservation time is 3-6 hours.

4. The use according to claim 2, characterized in that: The gas providing the reducing atmosphere includes hydrogen and / or carbon monoxide.

5. The use according to claim 2 or 4, characterized in that: The reduction reaction is carried out at a temperature of 100 to 300° C. and for a time of 0.5 to 2 hours.

6. The use according to claim 2, characterized in that: The solvent includes one or more of water, ethanol, methanol, glacial acetic acid, n-hexane, cyclohexane and toluene.

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