KR20150075233A - Metanation catalyst with high hydrostability and the method for preparing thereof - Google Patents

Abstract

The present invention relates to a methane synthetic catalyst having excellent durability and a method for producing the same. The methane synthetic catalyst is a catalyst for synthesizing methane from a synthetic gas including CO, CO_2, and H_2. The catalyst comprises: a carrier; iron (Fe), calcium (Ca), or a combination thereof dipped in the carrier; nickel (Ni); and magnesium (Mg). According to the present invention, provided is a catalyst having excellent durability even in a high temperature environment of 700°C or more exposed to moisture and also having a high carbon dioxide conversion rate, so that the catalyst is not denatured and the properties thereof are not degraded in a condition including high temperature and high pressure steam, thereby improving work efficiency in synthesizing methane.

Description

TECHNICAL FIELD The present invention relates to a methane synthesis catalyst having excellent water durability and a method for producing the same,

The present invention relates to a methane synthesis catalyst having excellent durability and a method for producing the same, and more particularly, to a methane synthesis catalyst having excellent durability, and more particularly, And a method for producing the same.

Methane is the simplest alkane compound of molecular formula CH ₄ and is also the main component of natural gas. The coupling angle of methane is 109.5 degrees. When one methane molecule is burned by oxygen, one carbon dioxide (CO ₂ ) molecule and two water molecules (H ₂ O) are produced. Methane is the most abundant source of alkane compounds in the world.

Meanwhile, the methane may be synthesized from a synthesis gas. The synthesis gas refers to a mixed gas of hydrogen (H ₂ ), carbon dioxide (CO ₂ ), and carbon monoxide (CO) The production process involves the reforming of liquid hydrocarbons or natural gas through oxidants, or the gasification of biomass such as coal or wood chips.

The synthesis gas thus produced is mainly used for synthesizing compounds such as ammonia, methanol and methane. In recent years, synthesis gas of Fischer-Tropsch synthesis or DME (Di-Methyl-Ether) The importance as intermediate raw material gas in the manufacturing process is increasing.

The reaction for the synthesis of methane by the reaction of carbon monoxide (CO), carbon dioxide (CO ₂ ) and hydrogen (H ₂ ) is as follows.

CO + 3H _{2 -} > CH ₄ + H ₂ O (reaction heat: 206 kJ / mol)

CO ₂ + 4H _{2 -} > CH ₄ + 2H ₂ O (reaction heat: 165 kJ / mol)

Referring to equations (1) and (2) above, when carbon monoxide or carbon dioxide reacts with hydrogen to produce methane (CH ₄ ), a large amount of heat is generated, thereby raising the internal temperature of the catalyst and the reactor to about 600 ° C. or higher . Therefore, in the case of the methane synthesis catalyst, a high temperature durability capable of withstanding a temperature of at least 600 ° C is required to withstand the high heat generated during the synthesis reaction.

As a method for solving the problem caused by such a high exothermic reaction, there is a method of cooling the heat generated in the methane synthesis reaction by introducing water having high heat capacity in a vapor state together with carbon monoxide, carbon dioxide and hydrogen as reaction gases (US 1974 -503684). However, for this purpose, a catalyst free of denaturation and deterioration is required under the conditions of high temperature and high pressure including steam.

On the other hand, in a general methane synthesis process, a multi-stage reaction system is constructed due to a high reaction heat, and a methane conversion rate is increased step by step to finally synthesize methane at a high concentration. At this time, in the reaction of each step, water generated from methane synthesis and carbon monoxide react with each other to generate a part of carbon dioxide. Therefore, it is advantageous to use a catalyst having a high conversion ratio of carbon dioxide to improve the process efficiency.

Therefore, when a catalyst having excellent durability at a high temperature of 700 占 폚 or higher and having no denaturation and property degradation under high temperature and high pressure conditions including steam is developed, it is expected to be useful in related fields.

One aspect of the present invention is to provide a catalyst that performs effective methane synthesis reaction even under high-temperature and high-pressure conditions containing a large amount of steam.

Another aspect of the present invention is to provide a method for producing such a catalyst having excellent water durability.

According to one aspect of the present invention, CO, CO ₂ And a catalyst for synthesizing methane from a synthesis gas containing H ₂ , the catalyst comprising: a carrier; And iron (Fe), calcium (Ca) or a combination thereof supported on the carrier; Nickel (Ni); And magnesium (Mg).

The catalyst comprises 20 to 85 parts by weight of a carrier per 100 parts by weight of the total catalyst; And more than 0 to 10 parts by weight of iron (Fe), more than 0 to 10 parts by weight of calcium (Ca), or a combination thereof; 20 to 40 parts by weight of nickel; And more than 0 to 20 parts by weight of magnesium.

The carrier is preferably alumina, silica or a combination thereof.

According to another aspect of the present invention there is provided a process for preparing a catalyst precursor comprising dispersing a catalyst precursor in water; Heating the catalyst precursor dispersed in water; Introducing ammonia water to induce precipitation; Removing moisture of the precipitated catalyst to obtain a solid content; Removing the base component from the solid content using distilled water; Drying; And a step of heat-treating the methane synthesis catalyst.

The catalyst precursor may include a carrier precursor; And an iron (Fe) precursor, a calcium (Ca) precursor or a combination thereof supported on a carrier; Nickel (Ni) precursor; And a magnesium (Mg) precursor.

The carrier precursor is preferably aluminum nitrate 9 hydrate ((Al ₂ NO ₃ ) ₃ 9H ₂ O), tetraethylorthosilicate (Si (OC ₂ H ₅ ) ₄ ) or a combination thereof.

The nickel precursor is nickel nitrate hexahydrate _{(Ni (NO 3) 2 ·} 6H 2 O), nickel acetate tetrahydrate _{((CH 3 CO 2) 2} Ni · 4H 2 O), 6 hydrate of nickel chloride (NiCl ₂ · 6H ₂ O) and nickel carbonate tetrahydrate (NiCO ₃ .2Ni (OH) ₂ .4H ₂ O).

The magnesium precursor is magnesium nitrate hexahydrate _{(Mg (NO 3) 2 ·} 6H 2 O), magnesium acetate tetrahydrate _{((CH 3 CO 2) 2} Mg · 4H 2 O), 6 hydrates of magnesium chloride (MgCl ₂ · 6H ₂ O) and is preferably selected from the group consisting of a magnesium carbonate _{((MgCO 3) 4 Mg (} OH) 2 · 5H 2 O).

The calcium precursor may be at least one selected from the group consisting of calcium nitrate tetrahydrate (Ca (NO ₃ ) ₂揃 4H ₂ O), calcium chloride dihydrate (CaCl ₂揃 2H ₂ O), calcium acetate (Ca (CH ₃ COO) ₂揃 2H ₂ O) (Ca (OH) _2), and is preferably selected from the group consisting of calcium carbonate (CaCO _3).

The iron precursor may be selected from ferric nitrate 9 hydrate (Fe (NO ₃ ) ₂ .9H ₂ O), ferrous chloride tetrahydrate (FeCl ₂ .4H ₂ O), ferric chloride hexahydrate (FeCl ₃ .6H ₂ O) Hydrate (FeSO ₄ .7H ₂ O).

The heating step is preferably performed at a temperature of 50 to 60 캜.

The step of inducing the precipitation is preferably performed at a pH of 9 to 10.

Preferably, the step of removing the base component is performed such that the pH of the recovered distilled water becomes 7 to 8. [

The drying step is preferably performed at a temperature of 190 to 250 ° C.

The heat treatment is preferably performed at a temperature of 700 to 900 ° C.

According to the present invention, a catalyst having excellent durability even at a high temperature of 700 ° C or more exposed to moisture and having a high carbon dioxide conversion rate is provided, so that denaturation and deterioration of the catalyst do not occur under conditions including high temperature and high pressure steam The process efficiency of the non-methane synthesis can be improved.

FIG. 1 is a graph showing the results of measurement of conversion of carbon monoxide and hydrogen of the catalyst of Comparative Example 1 according to presence or absence of steam.
2 is a graph showing the results of measurement of carbon monoxide and hydrogen conversion rates of the catalysts disclosed in Comparative Example 1 and Examples 1 to 4 under the condition that steam is included.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below.

The present invention relates to a synthesis gas obtained from gasification of coal or biomass or from by-product gas such as petrochemical industry, that is, CO, CO ₂ And a method for producing a catalyst for use in a method for synthesizing methane, which is a main component of natural gas, using H ₂ mixed gas.

According to the present invention, CO, CO ₂ And a catalyst for synthesizing methane from a synthesis gas containing H ₂ , the catalyst comprising: a carrier; And iron (Fe), calcium (Ca) or a combination thereof supported on the carrier; Nickel (Ni); And magnesium (Mg).

More specifically, the catalyst comprises 20 to 85 parts by weight of a carrier per 100 parts by weight of the total catalyst; And more than 0 to 10 parts by weight of iron (Fe), more than 0 to 10 parts by weight of calcium (Ca), or a combination thereof; 20 to 40 parts by weight of nickel; And more than 0 to 20 parts by weight of magnesium.

In the present invention, the iron (Fe), calcium (Ca) or a combination thereof; Nickel (Ni); (Fe), calcium (Ca), or a combination thereof together with nickel and magnesium and magnesium (Mg), and only when the composition of the above components is satisfied, the effect of the present invention is obtained . More preferably, the component is comprised of more than 0 to 10 parts by weight of iron (Fe), more than 0 to 10 parts by weight of calcium (Ca), or a combination thereof.

On the other hand, when nickel is contained in an amount of less than 20 parts by weight per 100 parts by weight of the total catalyst, CO ₂ conversion is lowered and catalyst efficiency is lowered. When nickel is more than 40 parts by weight per 100 parts by weight of the total catalyst, Thereby reducing the lifetime of the catalyst. there is a problem.

Meanwhile, the magnesium is preferably contained in an amount of more than 0 to 20 parts by weight per 100 parts by weight of the total catalyst. When magnesium is contained in an amount exceeding 20 parts by weight per 100 parts by weight of the total catalyst, the CO conversion is deteriorated.

In the present invention, the content of the remainder, based on 100 parts by weight of the total catalyst, is the content of the carrier. Preferably, the carrier is included in an amount of 20 to 85 parts by weight per 100 parts by weight of the total catalyst.

The carrier may be alumina, silica or a combination thereof.

Meanwhile, the catalyst of the present invention may include a step of dispersing a catalyst precursor in water; Heating the catalyst precursor dispersed in water; Introducing ammonia water to induce precipitation: removing moisture of the precipitated catalyst to obtain a solid content; Removing the base component from the solid content using distilled water; Drying; And a heat treatment step.

In the present invention, the catalyst precursor may include a carrier precursor; And an iron (Fe) precursor, a calcium (Ca) precursor or a combination thereof supported on a carrier; Nickel (Ni) precursor; And a magnesium (Mg) precursor.

In the method for producing a catalyst according to the present invention, the content of the catalyst, such as specific components and content of the catalyst, is as described above in connection with the catalyst.

The carrier precursor is preferably aluminum nitrate 9 hydrate ((Al ₂ NO ₃ ) ₃ 9H ₂ O), tetraethylorthosilicate (Si (OC ₂ H ₅ ) ₄ ) or a combination thereof.

The nickel precursor is nickel nitrate hexahydrate _{(Ni (NO 3) 2 ·} 6H 2 O), nickel acetate tetrahydrate _{((CH 3 CO 2) 2} Ni · 4H 2 O), 6 hydrate of nickel chloride (NiCl ₂ · 6H ₂ O) and nickel carbonate tetrahydrate (NiCO ₃ .2Ni (OH) ₂ .4H ₂ O).

The magnesium precursor is magnesium nitrate hexahydrate _{(Mg (NO 3) 2 ·} 6H 2 O), magnesium acetate tetrahydrate _{((CH 3 CO 2) 2} Mg · 4H 2 O), 6 hydrates of magnesium chloride (MgCl ₂ · 6H ₂ O) and is preferably selected from the group consisting of a magnesium carbonate _{((MgCO 3) 4 Mg (} OH) 2 · 5H 2 O).

The calcium precursor may be at least one selected from the group consisting of calcium nitrate tetrahydrate (Ca (NO ₃ ) ₂揃 4H ₂ O), calcium chloride dihydrate (CaCl ₂揃 2H ₂ O), calcium acetate (Ca (CH ₃ COO) ₂揃 2H ₂ O) (Ca (OH) _2), and is preferably selected from the group consisting of calcium carbonate (CaCO _3).

The iron precursor may be selected from ferric nitrate 9 hydrate (Fe (NO ₃ ) ₂ .9H ₂ O), ferrous chloride tetrahydrate (FeCl ₂ .4H ₂ O), ferric chloride hexahydrate (FeCl ₃ .6H ₂ O) Hydrate (FeSO ₄ .7H ₂ O), but is not particularly limited thereto.

In the step of dispersing the precursor in water, the amount of water for dispersion is not particularly limited, and an appropriate amount of water for sufficient dispersion can be used. However, it is preferable to use 3 to 5 times water based on the weight of the entire catalyst precursor.

When the dispersion of the catalyst precursor is completed, a step of heating the dispersed catalyst precursor is performed, and the heating step is preferably performed at a temperature of 50 to 60 ° C.

And then introducing ammonia water to induce precipitation, and the step of inducing precipitation is preferably performed at a pH of 9 to 10. When the above-mentioned pH range is satisfied, a high degree of metal crystallization can be obtained.

Ammonia water used in the step of inducing precipitation is not particularly limited, but ammonia water having a concentration of about 30 wt% is preferably used, and it is more preferable that the step of inducing precipitation proceeds with stirring.

After the precipitate is generated by the step of inducing the homologue, a step of heating and aging the temperature may be further performed. Preferably, the aging step is carried out at a temperature of 80 to 100 DEG C for 2 to 6 hours. When the aging step is completed, the temperature is cooled to room temperature.

And subsequently removing the water of the precipitated catalyst to obtain a solid content. The process of removing moisture is not particularly limited, but it is possible to obtain a solid content by removing water through a filter, for example. The filter which can be used at this time is also not particularly limited, but polypropylene (PP) or polyester-based filter cloth excellent in resistance to alkali and high temperature stability of 100 deg. C or more can be used.

And then removing the base component from the solid component using distilled water. In the step of removing the base component, the pH of the recovered distilled water is preferably adjusted to 7 to 8. That is, distilled water is preferably poured into the solid component to remove the base component, and if the base component is not sufficiently removed, the characteristics of the catalyst may be deteriorated.

The solid fraction from which the base is removed can be obtained as a final catalyst through a drying step and a heat treatment step.

The drying step is preferably carried out at a temperature of 190 to 250 ° C. If the temperature of the drying step is lower than 190 ° C., drying is not sufficiently performed. If the drying step is carried out at a temperature higher than 250 ° C. The catalyst characteristics may be deformed. More preferably, the drying is performed at 200 to 220 ° C.

The heat treatment is preferably performed at a temperature of 700 to 900 ° C. If the temperature of the heat treatment is less than 700 ° C., the calcination is not sufficiently performed and the catalytic activity may be deteriorated. If the heat treatment is 900 Lt; 0 > C, the sintering of the catalyst occurs and the catalyst characteristics may be deformed. It is more preferable that the heat treatment is performed at 700 to 800 ° C.

Further, a step of subsequently reducing the catalyst may be performed in the heat treatment step. The nickel in the catalyst obtained after the heat treatment is present in the form of nickel oxide, and the nickel oxide can be converted to nickel by performing the reduction step of the catalyst. The reduction of the catalyst is preferably performed at a temperature of 400 to 800 ° C. for 4 to 8 hours.

Hereinafter, the present invention will be described more specifically by way of specific examples. The following examples are provided to aid understanding of the present invention, and the scope of the present invention is not limited thereto.

< Example >

Comparative Example  One

4 liter of distilled water, 396 g of nickel precursor nickel nitrate, 422 g of magnesium precursor magnesium precursor, and 1709 g of aluminum nitrate precursor were mixed and heated to 60 캜. To the mixed solution, 1.1 liters of ammonia water having a concentration of 30 wt% was added and stirred sufficiently. Thereafter, ammonia water was further slowly added thereto to adjust the pH of the mixed solution to 9 to 10. Subsequently, the temperature was increased to 90 DEG C and stirred for 2 hours. Thereafter, the solution was cooled to room temperature and stirred to remove water through a filter to obtain a solid content. Further, the base component in the solid was removed with distilled water. The pH of the recovered distilled water was adjusted to 7 to 8. Then, the solid component from which the base component was removed was calcined at 500 ° C for 6 hours to prepare a catalyst including 20 parts by weight of nickel and 10 parts by weight of magnesium.

Example  One

Except that 29 g of the iron precursor was mixed together and 1671 g of aluminum nitrate were mixed in the process for producing the catalyst described in Comparative Example 1, 10 parts by weight of magnesium, and 1% by weight of iron.

Example  2

Except that 145 g of the iron precursor were mixed together and 1519 g of aluminum nitrate was mixed in the process of preparing the catalyst of Comparative Example 1 to obtain calcium 0 weight , 20 parts by weight of nickel, 10 parts by weight of magnesium and 5% by weight of iron.

Example  3

Except that 145 g of the iron precursor and 118 g of the calcium precursor were mixed together and 1313 g of aluminum nitrate were mixed in the process of preparing the catalyst disclosed in the Comparative Example 1, , 20 parts by weight of nickel, 10 parts by weight of magnesium, 5% by weight of iron and 5% by weight of calcium.

Example  4

Except that 594 g of the nickel precursor, 145 g of the iron precursor and 118 g of the calcium precursor were mixed together and 938 g of aluminum nitrate was mixed in the process of manufacturing the catalyst disclosed in Comparative Example 1, By the same process, a catalyst was prepared comprising 30 parts by weight of nickel, 10 parts by weight of magnesium, 8% by weight of iron and 8% by weight of calcium.

Experimental Example  One

In the case of the catalyst prepared in Comparative Example contains only gas containing 5 hours after the reduction reaction gas, the ratio of CO / H ₂ at 700 ℃ under hydrogen atmosphere to 1/3, whereby the CO and H ₂ 45 vol% (H ₂ O) was injected into the reactor, and the pressure was fixed at 20 bar.

At this time, the reaction temperature was changed from 250 ° C. to 450 ° C., and the reaction product was analyzed by using a gas analyzer. Generating a CH ₄ or CO ₂ by the reaction of CO and H ₂ and the CO conversion was calculated according to the reaction temperature, based on the consumption of CO are shown in Figure 1. The CO conversion result of the steam atmosphere.

The results are shown in FIG. 1. As shown in FIG. 1, in the case of the catalyst of Comparative Example 1, the conversion of CO was increased in the vicinity of 250 ° C. under the condition of no steam, Catalyst &quot; means that the catalyst exhibits activity. On the contrary, it can be confirmed that the catalyst starts to show activity at about 270 to 300 ° C under the condition of containing steam.

When the catalytic activation temperature is increased, the initial reaction temperature must be increased, so that more energy is consumed and the operation cost of the process is increased. Therefore, it is advantageous that the activation temperature of the catalyst is low in view of the efficiency of the reaction and the economy.

Experimental Example  2

The catalyst prepared in Comparative Example 1 and Examples 1 to 4 was reduced under a hydrogen atmosphere at 700 ° C. for 5 hours, and then a gas containing CO / H _{2 in} a ratio of 1/3 and CO and H ₂ 45 vol % Steam (H ₂ O) was injected into the reactor while the pressure was fixed at 20 bar.

At this time, the reaction temperature was changed from 250 ° C. to 450 ° C., and the reaction product was analyzed by using a gas analyzer. By the reaction of CO and H ₂ , CH ₄ Or CO ₂ , and the CO conversion according to the reaction temperature was calculated based on the consumption amount of CO. The CO conversion rate according to the catalyst composition is shown in FIG.

As can be seen from FIG. 2, the catalysts of Examples 1 to 4 according to the present invention show an increase in CO conversion at around 250 ° C. even under the condition of steam, It means visible.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be obvious to those of ordinary skill in the art.

Claims (15)

CO, CO ₂ And a catalyst for synthesizing methane from a synthesis gas containing H ₂ ,
carrier; And
Iron (Fe), calcium (Ca), or a combination thereof supported on the carrier; Nickel (Ni); And magnesium (Mg).
The catalyst according to claim 1,
20 to 85 parts by weight of a carrier per 100 parts by weight of the total catalyst; And
More than 0 to 10 parts by weight of iron (Fe), more than 0 to 10 parts by weight of calcium (Ca), or a combination thereof; 20 to 40 parts by weight of nickel; And magnesium exceeding 0 and 20 parts by weight
&Lt; / RTI &gt;
3. The methane synthesis catalyst according to claim 2, wherein the carrier is alumina, silica or a combination thereof.
Dispersing the catalyst precursor in water;
Heating the catalyst precursor dispersed in water;
Introducing ammonia water to induce precipitation;
Removing moisture of the precipitated catalyst to obtain a solid content;
Removing the base component from the solid content using distilled water;
Drying; And
Step of heat treatment
&Lt; / RTI &gt;
5. The process of claim 4, wherein the catalyst precursor
Carrier precursors; And
An iron (Fe) precursor, a calcium (Ca) precursor or a combination thereof supported on a carrier; Nickel (Ni) precursor; And a magnesium (Mg) precursor.
The method of claim 4, wherein the support precursor is selected from the group consisting of aluminum nitrate nonahydrate ((Al ₂ NO ₃ ) ₃ 9H ₂ O), tetraethylorthosilicate (Si (OC ₂ H ₅ ) ₄ ) Gt;
The method of claim 4, wherein the nickel precursor is selected from the group consisting of nickel nitrate hexahydrate (Ni (NO ₃ ) ₂ .6H ₂ O), nickel acetate tetrahydrate ((CH ₃ CO ₂ ) ₂ Ni 4H ₂ O), nickel chloride hexahydrate (NiCl ₂ .6H ₂ O) and nickel carbonate tetrahydrate (NiCO ₃ .2Ni (OH) ₂ .4H ₂ O).
The method of claim 4, wherein the magnesium precursor is selected from the group consisting of magnesium nitrate hexahydrate (Mg (NO ₃ ) ₂ .6H ₂ O), magnesium acetate tetrahydrate ((CH ₃ CO ₂ ) ₂ Mg 4H ₂ O), magnesium chloride hexahydrate (MgCl ₂ .6H ₂ O) and magnesium carbonate ((MgCO ₃ ) ₄ Mg (OH) ₂ .5H ₂ O).
The method of claim 4, wherein the calcium precursor is calcium nitrate tetrahydrate _{(Ca (NO 3) 2 ·} 4H 2 O), calcium chloride dihydrate _{(CaCl 2 · 2H 2 O)} , calcium acetate _{(Ca (CH 3 COO) 2} · 2H ₂ O), calcium hydroxide (Ca (OH) ₂ ) and calcium carbonate (CaCO ₃ ).
The method of claim 4, wherein the iron precursor is nitrate, ferrous nonahydrate _{(Fe (NO 3) 2 ·} 9H 2 O), ferrous chloride tetrahydrate _{(FeCl 2 · 4H 2 O)} , ferric chloride hexahydrate (FeCl ₃ · 6H ₂ O) and ferrous sulfate heptahydrate (FeSO ₄ .7H ₂ O).
5. The method of claim 4, wherein the heating is performed at a temperature of 50 to 60 占 폚.
5. The method of claim 4, wherein the step of inducing precipitation is carried out at a pH of from 9 to 10.
5. The method of claim 4, wherein the step of removing the base component is carried out so that the pH of the recovered distilled water becomes 7 to 8. [
The method of claim 4, wherein the drying is performed at a temperature of 190 to 250 ° C.
5. The method of claim 4, wherein the heat treatment is performed at a temperature of 700 to 900 占 폚.

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