阅读说明：本技术 富氢环境下的co甲烷化催化剂的制备方法及由该方法制备的催化剂 (Preparation method of CO methanation catalyst in hydrogen-rich environment and catalyst prepared by method ) 是由 陈斌 蒋汪洋 覃春平 周英 徐沾 倪龙军 于 2021-09-03 设计创作，主要内容包括：本发明涉及一种富氢环境下的CO甲烷化催化剂的制备方法及催化剂,该制备方法包括以下步骤：步骤S1,利用低钠拟薄水铝石制备氧化铝粉；步骤S2,利用氧化铝粉制备半成品,具体包括：选用钌的硝酸物或氯化物,以及铂和/或铑的硝酸物和/或氯化物,配置成溶液a；选用枸橼酸、碳酸氢钠、硝酸铈、硝酸镧、硝酸镁和无水碳酸钠中的至少两种配置成溶液b；将溶液a和溶液b混合均匀后得到混合溶液；利用混合溶液浸渍或者喷淋氧化铝粉,过滤洗涤,烘干后,压制成型；将成型后的颗粒焙烧,得到半成品；以及步骤S3,对步骤S2中的半成品进行活化处理得到成品催化剂。本发明制备了CO脱除精度高、使用条件温和的CO甲烷化催化剂。(The invention relates to a preparation method of a CO methanation catalyst in a hydrogen-rich environment and the catalyst, wherein the preparation method comprises the following steps: step S1, preparing alumina powder by using low-sodium pseudo-boehmite; step S2, preparing a semi-finished product by using the alumina powder, which specifically comprises the following steps: preparing a solution a by using nitric acid or chloride of ruthenium and nitric acid and/or chloride of platinum and/or rhodium; at least two of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate are selected to prepare a solution b; uniformly mixing the solution a and the solution b to obtain a mixed solution; dipping or spraying alumina powder by using the mixed solution, filtering, washing, drying and then pressing and forming; roasting the formed particles to obtain a semi-finished product; and step S3, activating the semi-finished product in the step S2 to obtain a finished product catalyst. The CO methanation catalyst prepared by the method has high CO removal precision and mild use conditions.)

1. A preparation method of a CO methanation catalyst under a hydrogen-rich environment is characterized by comprising the following steps:

step S1, preparing alumina powder by using low-sodium pseudo-boehmite;

step S2, preparing a semi-finished product by using the alumina powder, which specifically comprises the following steps:

step S21, using nitric acid or chloride of ruthenium and nitric acid and/or chloride of platinum and/or rhodium as catalyst active substance, preparing solution a for standby;

step S22, preparing a solution b by selecting at least two of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate;

step S23, uniformly mixing the solution a and the solution b to obtain a mixed solution;

step S24, adding the alumina powder obtained in the step S1 into the mixed solution, dipping for 2-4 hours, or uniformly spraying the mixed solution onto the alumina powder, filtering and washing, drying at 80-120 ℃, and then pressing and forming by using a tablet press;

step S25, roasting the particles formed in the step S24 for 2-8 hours at the temperature of 420-580 ℃, and obtaining a semi-finished product; and

and step S3, activating the semi-finished product in the step S2 to obtain a finished product catalyst.

2. The method for preparing the CO methanation catalyst under the hydrogen-rich environment according to claim 1, wherein the step S1 specifically comprises:

wetting low-sodium pseudo-boehmite with deionized water, mixing and grinding, sieving, drying at the temperature of 60-120 ℃ to obtain low-sodium pseudo-boehmite powder, adding a pore-forming agent and a lubricant into the dried low-sodium pseudo-boehmite powder, uniformly mixing, pre-pressing and forming by using a tablet press, crushing and granulating to obtain 20-80-mesh powder, and roasting the obtained 20-80-mesh powder at the temperature of 320-570 ℃ for 4-8 hours to obtain the required alumina powder.

3. The preparation method of the CO methanation catalyst under the hydrogen-rich environment according to claim 2, wherein in step S1, the ratio of the total weight of the pore-forming agent and the lubricant to the weight of the dried low-sodium pseudo-boehmite powder is 2-15%.

4. The method for preparing the CO methanation catalyst in the hydrogen-rich environment according to claim 2, wherein in step S1, the pore-forming agent comprises sesbania powder and/or cellulose.

5. The method for preparing the CO methanation catalyst in the hydrogen-rich environment according to claim 2, wherein in step S1, the lubricant comprises stearic acid.

6. The method for preparing the CO methanation catalyst in the hydrogen-rich environment according to claim 1, wherein in step S1, the pore volume of the low-sodium pseudoboehmite is not less than 0.3ml/g, and the specific surface area is not less than 250m²/g。

7. The method for preparing the CO methanation catalyst under the hydrogen-rich environment according to claim 1, wherein in the mixed solution a, the weight of the metal/the weight of the mixed solution a is 0.05-8%.

8. The method for preparing the CO methanation catalyst under the hydrogen-rich environment according to claim 1, wherein in the mixed solution b, the content of each component of at least two of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate for preparing the solution b is 0.1-5% by weight of the alumina powder.

9. The method for preparing the CO methanation catalyst in the hydrogen-rich environment according to claim 1, characterized in that a semi-finished product is subjected to an activation treatment by using a reducing solution or an industrial gas.

10. A catalyst produced by the production method according to any one of claims 1 to 9.

Technical Field

The invention relates to the field of catalysts, in particular to a preparation method of a CO methanation catalyst in a hydrogen-rich environment and a catalyst prepared by the method.

Background

The CO adsorbent or CO conversion catalyst in the current market is divided into two types, namely CO removal by adopting a physical adsorption or chemical adsorption method and CO conversion into harmless methane by adopting a chemical reaction. The physical or chemical adsorption method is simple to operate, the nickel-based CO methanation catalyst has higher CO conversion rate, but the adsorbent product has the following defects:

(1) the CO removal precision is not high, and the requirements of hydrogen fuel and hydrogen energy industries on CO cannot be met;

(2) the service life of the CO adsorbent is related to the content of active substances in the adsorbent, and the industrial use is obviously limited;

(3) the method for simultaneously methanation of carbon dioxide and carbon monoxide disclosed by the large connected compound has the advantages of higher use temperature of the used nickel catalyst, higher energy consumption and reaction condition on H₂/(CO+CO₂) The molar ratio is required to be higher.

Disclosure of Invention

In view of the above problems, the present invention has been made to provide a method for preparing a CO methanation catalyst in a hydrogen rich environment and a catalyst prepared by the method, which overcome the above problems or at least partially solve the above problems.

According to one aspect of the invention, a preparation method of a CO methanation catalyst in a hydrogen-rich environment is provided, which comprises the following steps: step S1, preparing alumina powder by using low-sodium pseudo-boehmite; step S2, preparing a semi-finished product by using the alumina powder, which specifically comprises the following steps: step S21, using nitric acid or chloride of ruthenium and nitric acid and/or chloride of platinum and/or rhodium as catalyst active substance, preparing solution a for standby; step S22, preparing a solution b by selecting at least two of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate; step S23, uniformly mixing the solution a and the solution b to obtain a mixed solution; step S24, adding the alumina powder obtained in the step S1 into the mixed solution, dipping for 2-4 hours, or uniformly spraying the mixed solution onto the alumina powder, filtering and washing, drying at 80-120 ℃, and then pressing and forming by using a tablet press; step S25, roasting the particles formed in the step S24 for 2-8 hours at the temperature of 420-580 ℃, and obtaining a semi-finished product; and step S3, activating the semi-finished product in the step S2 to obtain a finished product catalyst.

Preferably, step S1 specifically includes: wetting low-sodium pseudo-boehmite with deionized water, mixing and grinding, sieving, drying at the temperature of 60-120 ℃ to obtain low-sodium pseudo-boehmite powder, adding a pore-forming agent and a lubricant into the dried low-sodium pseudo-boehmite powder, uniformly mixing, pre-pressing and forming by using a tablet press, crushing and granulating to obtain 20-80-mesh powder, and roasting the obtained 20-80-mesh powder at the temperature of 320-570 ℃ for 4-8 hours to obtain the required alumina powder.

Preferably, in step S1, the ratio of the total weight of the pore-forming agent and the lubricant to the weight of the dried low-sodium pseudo-boehmite powder is 2-15%.

Preferably, in step S1, the pore former includes sesbania powder and/or cellulose.

Preferably, in step S1, the lubricant comprises stearic acid.

Preferably, in step S1, the low-sodium pseudoboehmite has a pore volume of 0.3ml/g or more and a specific surface area of 250m or more²/g。

Preferably, in the mixed solution a, the weight of the metal/the weight of the mixed solution a is 0.05 to 8%.

Preferably, in the mixed solution b, the content of each component of at least two of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate for preparing the solution b is 0.1-5% by weight of the alumina powder.

Preferably, the semifinished product is subjected to an activation treatment using a reducing solution or an industrial gas.

In a second aspect, the embodiments of the present invention provide a catalyst prepared by the preparation method of the first aspect.

The invention aims at trace CO in the field of hydrogen energy and hydrogen fuel, and prepares the CO methanation catalyst with high CO removal precision, convenient industrial use and operation and mild use conditions.

The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.

Detailed Description

The technical solution of the present invention is further described in detail with reference to the following examples.

The embodiment of the invention provides a preparation method of a CO methanation catalyst under a hydrogen-rich environment, which comprises the following steps:

step S1, preparing alumina powder by using low-sodium pseudo-boehmite.

Step S2, preparing solution a and solution b, specifically including:

step S21, using nitric acid or chloride of ruthenium and nitric acid and/or chloride of platinum and/or rhodium as catalyst active material, preparing solution a for standby.

And step S22, preparing a solution b by selecting at least two of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate.

And step S23, uniformly mixing the solution a and the solution b to obtain a mixed solution.

And S24, adding the alumina powder obtained in the step S1 into the mixed solution, soaking for 2-4 hours, or uniformly spraying the mixed solution onto the alumina powder, filtering and washing, drying at 80-120 ℃, and then pressing and forming by using a tablet press.

And step S25, roasting the particles formed in the step S24 at the temperature of 420-580 ℃ for 2-8 hours to obtain a semi-finished product.

And step S3, activating the semi-finished product in the step S2 to obtain a finished product catalyst.

Illustratively, step S1 specifically includes:

wetting low-sodium pseudo-boehmite with deionized water, mixing and grinding, sieving, drying at the temperature of 60-120 ℃ to obtain low-sodium pseudo-boehmite powder, adding a pore-forming agent and a lubricant into the dried low-sodium pseudo-boehmite powder, uniformly mixing, pre-pressing and forming by using a tablet press, crushing and granulating to obtain 20-80-mesh powder, and roasting the obtained 20-80-mesh powder at the temperature of 320-570 ℃ for 4-8 hours to obtain the required alumina powder. The lubricant may aid in the forming.

Illustratively, in step S1, the ratio of the total weight of the pore-forming agent and the lubricant to the weight of the dried low-sodium pseudo-boehmite powder is 2-15%.

Illustratively, in step S1, the pore former includes sesbania powder and/or cellulose.

Further, in step S1, the weight of the pore-forming agent is 2 to 10% of the weight of the dried low-sodium pseudo-boehmite powder.

Illustratively, in step S1, the lubricant includes stearic acid.

Further, in step S1, the weight of the lubricant is 2 to 5% of the weight of the dried low-sodium pseudo-boehmite powder.

Illustratively, in step S1, a commercially available low sodium pseudoboehmite may be selected, preferablyThe pore volume is more than or equal to 0.3ml/g, the specific surface area is more than or equal to 250m²A low sodium pseudoboehmite per gram.

Illustratively, in the mixed solution a, the weight of the metal/the weight of the mixed solution a is 0.05 to 8%.

Illustratively, in the mixed solution b, at least two of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate for preparing the solution b are each contained in an amount of 0.1 to 5% by weight of the alumina powder.

Illustratively, the ratio of solution a to solution b in the mixed solution is not particularly limited, but the total solution volume requires a water absorption of ≈ alumina powder.

For example, in step S3, the activation process for the semi-finished product may be performed by using a reducing solution or an industrial gas.

In one embodiment, the method of activating the semifinished item with the reducing solution is as follows:

and step S31, preparing a solution c with the concentration of 5-200 g/L by using sodium borohydride or potassium borohydride.

And S32, adding the semi-finished product obtained in the step S2 into the solution c, soaking for 1-3 h, washing until the pH value of the aqueous solution is approximately equal to 7, filtering to dryness, and drying at 100-150 ℃ to constant weight to obtain the finished product catalyst.

The aqueous solution herein is an aqueous solution after washing, that is, excess water after washing.

In another embodiment, the semi-finished product in step S2 is activated by using a mixture gas including N₂And H₂，N₂The volume ratio of the mixed gas is 95-98%, and the treatment conditions are as follows:

treatment step	1	2	3	4
					Temperature/. degree.C	120～150	200～260	300～400	Cooling to room temperature
Time/h	2～4	2～5	4～8

The principle of methanation removal of carbon monoxide:

the catalyst is prepared by adopting an impregnation method or a spray loading method and pressing and forming, and the carbon monoxide methanation catalyst with reasonable distribution of active components, moderate carrier void structure, good selectivity and high activity is prepared. At an airspeed of 500-8000 h^-1And under the conditions that the pressure is 1.0-2.0 MPa and the temperature is 120-200 ℃, the trace carbon monoxide in the hydrogen fuel reacts with the hydrogen to generate methane, so that the carbon monoxide is removed to be below 0.02 ppm.

Example 1

Step S1 specifically includes:

wetting low-sodium pseudo-boehmite with deionized water, mixing and grinding, sieving, drying in an environment of 60 ℃ to obtain a low-sodium pseudo-boehmite powder, adding a pore-forming agent and a lubricant into the dried low-sodium pseudo-boehmite powder, uniformly mixing, pre-pressing and forming by using a tablet press, crushing and granulating to obtain 20-80-mesh powder, and roasting the obtained 20-80-mesh powder for 8 hours at the temperature of 320 ℃ to obtain the required alumina powder. The lubricant may aid in the forming.

Illustratively, in step S1, the ratio of the combined weight of pore former and lubricant to the weight of the dried low sodium pseudo-boehmite powder is 2%.

Further, in step S1, the weight of the pore-forming agent is 2% of the weight of the dried low-sodium pseudo-boehmite powder.

Further, in step S1, the weight of the lubricant is 2% of the weight of the dried low-sodium pseudo-boehmite powder.

Illustratively, in step S21, a nitric acid product of ruthenium, a nitric acid product of platinum, and a nitric acid product of rhodium are selected as the catalytically active material, and prepared into a solution a for use.

Illustratively, in step S21, a solution a is prepared in advance by using nitric acid of ruthenium, nitric acid of platinum and chloride of rhodium as the catalyst active material.

Illustratively, in step S21, a nitric acid compound of ruthenium, a nitric acid compound of platinum and a nitric acid compound of rhodium are selected as the catalytically active species, and prepared into a solution a for use.

Illustratively, in step S21, ruthenium nitrate, platinum chloride and rhodium chloride are selected as the catalyst active material, and prepared into solution a for use.

Illustratively, in step S21, a nitric acid product of ruthenium, a nitric acid product of platinum, and a nitric acid product of rhodium are selected as the catalytically active material, and prepared into a solution a for use.

Illustratively, in step S21, a solution a is prepared in advance by using nitric acid of ruthenium, nitric acid of platinum and chloride of rhodium as the catalyst active material.

Illustratively, in step S21, a nitric acid compound of ruthenium, a nitric acid compound of platinum and a nitric acid compound of rhodium are selected as the catalytically active species, and prepared into a solution a for use.

Illustratively, in step S21, ruthenium nitrate, platinum chloride and rhodium chloride are selected as the catalyst active material, and prepared into solution a for use.

Illustratively, in step S21, a nitric acid product of ruthenium and a nitric acid product of platinum are selected as the catalytically active species and prepared as a solution a for use.

Illustratively, in step S21, a solution a is prepared in advance by using nitric acid of ruthenium and chloride of platinum as the catalyst active material.

Illustratively, in step S21, a nitric acid product of ruthenium and a nitric acid product of rhodium are selected as the catalyst active materials and prepared into a solution a for standby.

Illustratively, in step S21, a solution a is prepared in advance by using nitric acid of ruthenium and chloride of rhodium as the catalyst active material.

Illustratively, in step S21, ruthenium chloride and platinum nitrate are selected as the catalytically active species and are pre-prepared as solution a for use.

Illustratively, in step S21, ruthenium chloride and platinum chloride are selected as the catalyst active material and are pre-prepared into solution a for use.

Illustratively, in step S21, ruthenium chloride and rhodium nitrate are selected as the catalyst active material, and prepared into solution a for use.

Illustratively, in step S21, ruthenium chloride and rhodium chloride are selected as the catalyst active material and prepared into solution a for use.

Illustratively, in step S22, any two of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate are selected to prepare the solution b, wherein the content of each of the any two components is 0.1% of the weight of the alumina powder.

Illustratively, in step S22, any three of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate are selected to prepare the solution b, wherein the content of each of the any three components is 0.1% of the weight of the alumina powder.

Illustratively, in step S22, any four of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate are selected to prepare the solution b, wherein the content of each of the any four components is 0.1% of the weight of the alumina powder.

Illustratively, in step S24, any five of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate are selected to prepare the solution b, wherein the content of each of the five components is 0.1% of the weight of the alumina powder.

Illustratively, in step S24, citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate are selected to prepare the solution b, wherein each of the six components is 0.1% by weight of the alumina powder.

Illustratively, in the mixed solution a, the weight of the metal/the weight of the mixed solution a is 0.05%.

Illustratively, the concentration of solution c in step S31 is 5 g/L.

Illustratively, in step S32, the semi-finished product in step S2 is added into the solution c, soaked for 1h, washed until the pH of the aqueous solution is about 7, filtered to dryness, and dried to constant weight at 100 ℃ to obtain the finished catalyst.

Illustratively, N is the mixed gas obtained by activating the semi-finished product in step S2₂The volume ratio of the mixed gas is 95 percent.

Example 2

Step S1 specifically includes:

wetting low-sodium pseudo-boehmite with deionized water, mixing and grinding, sieving, drying at 90 ℃ to obtain low-sodium pseudo-boehmite powder, adding a pore-forming agent and a lubricant into the dried low-sodium pseudo-boehmite powder, uniformly mixing, pre-pressing and molding by using a tablet press, crushing and granulating to obtain 20-80-mesh powder, and roasting the obtained 20-80-mesh powder at 400 ℃ for 6 hours to obtain the required alumina powder. The lubricant may aid in the forming.

Illustratively, in step S1, the ratio of the combined weight of pore former and lubricant to the weight of the dried low sodium pseudo-boehmite powder is 7%.

Further, in step S1, the weight of the pore-forming agent is 7% of the weight of the dried low-sodium pseudo-boehmite powder.

Further, in step S1, the weight of the lubricant is 3% of the weight of the dried low-sodium pseudo-boehmite powder.

Illustratively, in step S21, a nitric acid product of ruthenium, a nitric acid product of platinum, and a nitric acid product of rhodium are selected as the catalytically active material, and prepared into a solution a for use.

Illustratively, in step S21, a solution a is prepared in advance by using nitric acid of ruthenium, nitric acid of platinum and chloride of rhodium as the catalyst active material.

Illustratively, in step S21, a nitric acid compound of ruthenium, a nitric acid compound of platinum and a nitric acid compound of rhodium are selected as the catalytically active species, and prepared into a solution a for use.

Illustratively, in step S21, ruthenium nitrate, platinum chloride and rhodium chloride are selected as the catalyst active material, and prepared into solution a for use.

Illustratively, in step S21, a nitric acid product of ruthenium, a nitric acid product of platinum, and a nitric acid product of rhodium are selected as the catalytically active material, and prepared into a solution a for use.

Illustratively, in step S21, a solution a is prepared in advance by using nitric acid of ruthenium, nitric acid of platinum and chloride of rhodium as the catalyst active material.

Illustratively, in step S21, a nitric acid compound of ruthenium, a nitric acid compound of platinum and a nitric acid compound of rhodium are selected as the catalytically active species, and prepared into a solution a for use.

Illustratively, in step S21, ruthenium nitrate, platinum chloride and rhodium chloride are selected as the catalyst active material, and prepared into solution a for use.

Illustratively, in step S21, a nitric acid product of ruthenium and a nitric acid product of platinum are selected as the catalytically active species and prepared as a solution a for use.

Illustratively, in step S21, a solution a is prepared in advance by using nitric acid of ruthenium and chloride of platinum as the catalyst active material.

Illustratively, in step S21, a nitric acid product of ruthenium and a nitric acid product of rhodium are selected as the catalyst active materials and prepared into a solution a for standby.

Illustratively, in step S21, a solution a is prepared in advance by using nitric acid of ruthenium and chloride of rhodium as the catalyst active material.

Illustratively, in step S21, ruthenium chloride and platinum nitrate are selected as the catalytically active species and are pre-prepared as solution a for use.

Illustratively, in step S21, ruthenium chloride and platinum chloride are selected as the catalyst active material and are pre-prepared into solution a for use.

Illustratively, in step S21, ruthenium chloride and rhodium nitrate are selected as the catalyst active material, and prepared into solution a for use.

Illustratively, in step S21, ruthenium chloride and rhodium chloride are selected as the catalyst active material and prepared into solution a for use.

Illustratively, in step S22, any two of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate are selected to prepare the solution b, wherein the content of each of the any two components is 2.5% of the weight of the alumina powder.

Illustratively, in step S22, any three of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate are selected to prepare the solution b, wherein the content of each of the any three components is 2.5% of the weight of the alumina powder.

Illustratively, in step S22, any four of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate are selected to prepare the solution b, wherein the content of each of the any four components is 2.5% of the weight of the alumina powder.

Illustratively, in step S24, any five of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate are selected to prepare the solution b, wherein the content of each of the five components is 2.5% of the weight of the alumina powder.

Illustratively, in step S24, citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate are selected to prepare solution b, wherein the content of each of the six components is 2.5% of the weight of the alumina powder.

Illustratively, in the mixed solution a, the weight of the metal/the weight of the mixed solution a is 4%.

An exemplary method for activating the semifinished product using the reducing solution is as follows:

illustratively, the concentration of the solution c in step S31 is 100 g/L.

Illustratively, in step S32, the semi-finished product in step S2 is added into the solution c, soaked for 2h, washed until the pH of the aqueous solution is about 7, filtered to dryness, and dried to constant weight at 120 ℃ to obtain the finished catalyst.

Illustratively, N is the mixed gas obtained by activating the semi-finished product in step S2₂The volume ratio of the mixed gas is 96%.

Example 3

Step S1 specifically includes:

wetting low-sodium pseudo-boehmite with deionized water, mixing and grinding, sieving, drying at 120 ℃ to obtain low-sodium pseudo-boehmite powder, adding a pore-forming agent and a lubricant into the dried low-sodium pseudo-boehmite powder, uniformly mixing, pre-pressing and molding by using a tablet press, crushing and granulating to obtain 20-80-mesh powder, and roasting the obtained 20-80-mesh powder for 4 hours at 570 ℃ to obtain the required alumina powder. The lubricant may aid in the forming.

Illustratively, in step S1, the ratio of the combined weight of pore former and lubricant to the weight of the dried low sodium pseudo-boehmite powder is 15%.

Further, in step S1, the weight of the pore-forming agent is 10% of the weight of the dried low-sodium pseudo-boehmite powder.

Further, in step S1, the weight of the lubricant is 5% of the weight of the dried low-sodium pseudo-boehmite powder.

Illustratively, in step S21, a nitric acid product of ruthenium, a nitric acid product of platinum, and a nitric acid product of rhodium are selected as the catalytically active material, and prepared into a solution a for use.

Illustratively, in step S21, a solution a is prepared in advance by using nitric acid of ruthenium, nitric acid of platinum and chloride of rhodium as the catalyst active material.

Illustratively, in step S21, a nitric acid compound of ruthenium, a nitric acid compound of platinum and a nitric acid compound of rhodium are selected as the catalytically active species, and prepared into a solution a for use.

Illustratively, in step S21, ruthenium nitrate, platinum chloride and rhodium chloride are selected as the catalyst active material, and prepared into solution a for use.

Illustratively, in step S21, a nitric acid product of ruthenium, a nitric acid product of platinum, and a nitric acid product of rhodium are selected as the catalytically active material, and prepared into a solution a for use.

Illustratively, in step S21, a solution a is prepared in advance by using nitric acid of ruthenium, nitric acid of platinum and chloride of rhodium as the catalyst active material.

Illustratively, in step S21, a nitric acid compound of ruthenium, a nitric acid compound of platinum and a nitric acid compound of rhodium are selected as the catalytically active species, and prepared into a solution a for use.

Illustratively, in step S21, ruthenium nitrate, platinum chloride and rhodium chloride are selected as the catalyst active material, and prepared into solution a for use.

Illustratively, in step S21, a nitric acid product of ruthenium and a nitric acid product of platinum are selected as the catalytically active species and prepared as a solution a for use.

Illustratively, in step S21, a solution a is prepared in advance by using nitric acid of ruthenium and chloride of platinum as the catalyst active material.

Illustratively, in step S21, a nitric acid product of ruthenium and a nitric acid product of rhodium are selected as the catalyst active materials and prepared into a solution a for standby.

Illustratively, in step S21, a solution a is prepared in advance by using nitric acid of ruthenium and chloride of rhodium as the catalyst active material.

Illustratively, in step S21, ruthenium chloride and platinum nitrate are selected as the catalytically active species and are pre-prepared as solution a for use.

Illustratively, in step S21, ruthenium chloride and platinum chloride are selected as the catalyst active material and are pre-prepared into solution a for use.

Illustratively, in step S21, ruthenium chloride and rhodium nitrate are selected as the catalyst active material, and prepared into solution a for use.

Illustratively, in step S21, ruthenium chloride and rhodium chloride are selected as the catalyst active material and prepared into solution a for use.

Illustratively, in step S22, any two of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate are selected to prepare the solution b, wherein the content of each of the any two components is 5% of the weight of the alumina powder.

Illustratively, in step S22, any three of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate are selected to prepare the solution b, wherein the content of each of the any three components is 5% of the weight of the alumina powder.

Illustratively, in step S22, any four of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate are selected to be prepared into the solution b, wherein the content of each of the any four components is 5% of the weight of the alumina powder.

Illustratively, in step S24, any five of citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate are selected to prepare the solution b, wherein the content of each of the five components is 5% of the weight of the alumina powder.

Illustratively, in step S24, citric acid, sodium bicarbonate, cerium nitrate, lanthanum nitrate, magnesium nitrate and anhydrous sodium carbonate are selected to prepare the solution b, wherein the content of each of the six components is 5% by weight of the alumina powder.

Illustratively, in the mixed solution a, the weight of the metal/the weight of the mixed solution a is 8%.

An exemplary method for activating the semifinished product using the reducing solution is as follows:

illustratively, the concentration of the solution c in step S31 is 200 g/L.

Illustratively, in step S32, the semi-finished product in step S2 is added into the solution c, soaked for 3h, washed until the pH of the aqueous solution is about 7, filtered to dryness, and dried to constant weight at 150 ℃ to obtain the finished catalyst.

Illustratively, N is the mixed gas obtained by activating the semi-finished product in step S2₂The volume ratio of the mixed gas is 98 percent.

Test data:

the raw material gas comprises the following components: h₂: balancing gas; CO: 22.98 ppm; CO2₂:20ppm。

Testing an instrument: ka Plus 8000 enhanced plasma chromatograph, detection precision: 0.01ppm.

And (3) testing conditions are as follows: space velocity: 5000h-1, pressure: 1.0 to 1.35MPa

The content of 0.00 in the table is a reading of a measuring instrument having an accuracy of 0.01ppm, which means that the measured value is < 0.01ppm.

Theoretically, if the CO is completely converted to methane at 90 deg.C, about 22.9ppm of methane should be formed, but the detected methane content is 0.10ppm, indicating that the CO does not form a corresponding amount of methane. Meanwhile, at 120 ℃, the consumption of CO is 22.98ppm and the consumption of CO2 is 4.58ppm, 27.56ppm methane should be theoretically generated, 28.66ppm methane is detected, the difference exists, and the difference possibly results from measurement errors, and at this time, the CO can be judged to be completely converted into CH₄I.e. the complete conversion temperature of CO is more than or equal to 120 ℃. Similarly, according to the subsequent CO consumption and CO₂Consumption, and CH₄When the methane production amount is approximately equal to 42.98ppm, CO and CO are determined₂Are all completely converted to methane, i.e. CO₂The complete conversion temperature is more than or equal to 200 ℃.

The embodiment of the invention also provides a CO methanation catalyst under a hydrogen-rich environment, which is prepared by the preparation method.

The above embodiments are provided to further explain the objects, technical solutions and advantages of the present invention in detail, it should be understood that the above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the scope of the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.