Metal oxide desulfurizer, method for preparing the same, and use thereof

Abstract

The application provides a metal oxide desulfurizer and a preparation method and application thereof, and belongs to the technical field of gas purification and desulfurization. The metal oxide desulfurizer is obtained by impregnating a nickel oxide or molybdenum oxide precursor on activated carbon, drying and calcining, and the metal oxide desulfurizer comprises oxygen-containing functional groups on the surface of the activated carbon and metal oxides. The metal oxide desulfurizer removes metal sulfides generated after desulfurization, and serves as a hydrogenation catalyst for thiophene sulfur.

Description

Technical Field

[0001] This invention relates to the field of gas purification and desulfurization technology, and in particular to a metal oxide desulfurizing agent, its preparation method, and its application. Background Technology

[0002] With the intensifying trend of global warming, carbon compliance and carbon neutrality are receiving increasing attention as important means of mitigating global warming. Coal accounts for a high proportion of my country's domestic petrochemical resources, and coal gasification technology is an effective means to reduce this proportion. However, coal gasification technology inevitably produces various sulfur-containing compounds. The presence of these sulfides can corrode equipment and pipelines, cause environmental pollution, and even harm human health. Therefore, the clean and efficient utilization of coal is a key issue for coal gasification technology. Metal oxide desulfurization, due to its advantages of high desulfurization precision and ease of operation, is currently a widely used industrial method for removing H2S. However, metal oxide desulfurizing agents are difficult to regenerate under mild conditions after desulfurization. Direct disposal of these agents generates solid waste that causes secondary pollution to the environment. Therefore, seeking resource utilization of spent desulfurizing agents is a key issue in the current research field of metal oxide desulfurizing agents.

[0003] For thiophene-type sulfur, such as organic sulfur C4H4S, hydrodesulfurization is usually used in industry. However, since the catalyst needs to be pre-sulfurized before use to convert the metal oxide into a metal sulfide with high hydrodesulfurization catalytic activity, the sulfiding agent used in the process will inevitably cause environmental pollution. Therefore, reducing the use of sulfiding agents and reducing the pollution caused by the pre-sulfurization of HDS catalysts is of great significance.

[0004] Therefore, a high-performance metal oxide desulfurizer is provided, which can also use the solid waste generated by the desulfurization reaction as a hydrogenation catalyst. This can solve the problem of solid waste treatment after the use of metal oxide desulfurizer, reduce the cost of pre-sulfurization of hydrogenation catalyst, and greatly reduce the environmental pollution problems caused by it. Summary of the Invention

[0005] This invention mainly addresses the problem of solid waste treatment generated after desulfurization of activated carbon in an oxygen-free atmosphere at room temperature. In order to solve the above-mentioned existing technical problems or some of them, the purpose of this invention is to provide a metal oxide desulfurizing agent, its preparation method and application.

[0006] According to one aspect of the present invention, a metal oxide desulfurizer is provided, wherein the metal oxide desulfurizer is made by impregnating a nickel oxide or molybdenum oxide precursor onto activated carbon, the metal oxide desulfurizer comprising oxygen-containing functional groups and metal oxides on the surface of the activated carbon.

[0007] The main innovations of the technical solution provided by the embodiments of the present invention are as follows: 1. The presence of nitrogen changes the electronic structure of Mo and Ni, causing interaction between Ni and Mo, making it easier to react with H2S to form the Ni-Mo-S phase, which has stronger catalytic performance in the hydrogenation of thiophene; 2. This patent realizes the coupling of room temperature adsorption desulfurization and atmospheric pressure hydrogenation desulfurization of molybdenum-nickel composite desulfurizer, while solving the problems caused by solid waste treatment of desulfurizer and presulfurization process of hydrogenation catalyst.

[0008] In some embodiments, the metal oxide desulfurizer is a molybdenum-nickel composite desulfurizer.

[0009] In some embodiments, nitrogen-containing functional groups and metal oxides are introduced onto the surface of activated carbon by impregnating it with nitric acid and a precursor solution containing ammonium molybdate and nickel nitrate.

[0010] In some embodiments, the metal oxide desulfurizer produces metal sulfides after removing sulfur compounds, such as H2S.

[0011] In another aspect of the present invention, a method for preparing a metal oxide desulfurizing agent is provided, wherein the metal oxide desulfurizing agent is the aforementioned metal oxide desulfurizing agent, and the preparation method includes the following steps:

[0012] Impregnation (1): Impregnate activated carbon in a precursor solution containing ammonium molybdate and nickel nitrate, and let it stand for 2-4 hours;

[0013] Drying (2): Place the impregnated activated carbon in an oven at 30-60°C. ℃ Dry for 12-16 hours;

[0014] Calcination (3): Place the dried activated carbon in a tube furnace and heat it to 300-500°C under an inert atmosphere. ℃ The metal oxide desulfurizer is obtained by calcining for 3-5 hours at a heating rate of 1-2℃ / min and an inert gas flow rate of 100-200ml / min.

[0015] In some embodiments, in step impregnation (1), the precursor solution containing ammonium molybdate and nickel nitrate is prepared by dissolving ammonium heptamolybdate and nickel nitrate hexahydrate in deionized water.

[0016] In some embodiments, when using a precursor solution prepared by dissolving ammonium heptamolybdate and nickel nitrate hexahydrate in deionized water, the activated carbon in step (1) is first impregnated in nitric acid and then dried in an oven. The dried activated carbon is then impregnated in a precursor solution prepared by dissolving ammonium heptamolybdate and nickel nitrate hexahydrate in deionized water.

[0017] In some embodiments, in step drying (2), the impregnated activated carbon is placed in an oven for drying.

[0018] In some embodiments, in step calcination (3), the dried activated carbon is placed in a tube furnace for calcination.

[0019] In another aspect of the invention, the application of a metal oxide desulfurizer to produce metal sulfides after the removal of sulfur compounds such as H2S is provided. The metal oxide desulfurizer is the metal oxide desulfurizer described above, or a metal oxide desulfurizer prepared by the method described above. The metal sulfides produced by the metal oxide desulfurizer after the removal of sulfur compounds such as H2S serve as hydrogenation catalysts for thiophene sulfur.

[0020] The metal oxide desulfurizing agent, its preparation method, and its application according to embodiments of the present invention have at least one of the following advantages:

[0021] The prepared nickel-molybdenum composite desulfurizer loaded on activated carbon achieves efficient removal of H2S under an oxygen-free atmosphere through the desulfurization performance of oxygen-containing functional groups, nitrogen-containing functional groups and metal oxides on the surface of activated carbon. At the same time, the metal sulfides generated after the desulfurizer is used as hydrogenation catalysts for thiophene sulfur, realizing the resource utilization of waste desulfurizer, while avoiding the cost increase and environmental pollution problems caused by the need for pre-sulfurization before the reaction of traditional hydrogenation catalysts.

[0022] Secondly, for hydrogenation catalysis, a relatively low content of active components results in high hydrogenation catalytic performance;

[0023] Metal oxide desulfurizers are obtained by impregnating nickel oxide or molybdenum oxide precursors onto nitric acid-impregnated activated carbon, followed by drying and calcination in an oxygen-free atmosphere. The activated carbon surface of the metal oxide desulfurizer contains oxygen-containing functional groups, nitrogen-containing functional groups, and metal oxides. The presence of oxygen-containing functional groups provides an oxygen source for the desulfurization reaction. The presence of nitrogen-containing functional groups promotes the dissociation of H2S adsorbed on the surface of the desulfurizer and alters the electronic structure of the metal oxides, thus promoting the reaction between the metal oxides and H2S. The metal oxides utilize their own desulfurization properties to remove H2S, and the maximum working sulfur capacity of the desulfurizer can reach 310 mg / g. Furthermore, because the Mo-S bonds generated in the desulfurization reaction are more easily broken, the metal sulfides produced after the use of the desulfurizer can be used as hydrogenation catalysts for thiophene sulfur, achieving a catalytic conversion rate of up to 85% for thiophene sulfur. Attached Figure Description

[0024] These and / or other aspects and advantages of the present invention will become apparent and readily understood from the following description of preferred embodiments taken in conjunction with the accompanying drawings, in which:

[0025] Figure 1This is a schematic flowchart of a method for preparing a metal oxide desulfurizer according to an embodiment of the present invention. Detailed Implementation

[0026] The features of the present invention are further illustrated below through specific embodiments. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall concept of the present invention and should not be construed as a limitation thereof.

[0027] The main objective of this invention is to provide a high-performance metal oxide desulfurizer and to address the problem of using the metal oxide desulfurizer as a hydrogenation catalyst in the solid waste after the desulfurization reaction, thereby providing a method for preparing and applying the metal oxide desulfurizer.

[0028] The metal oxide desulfurizing agent described in the embodiments of the present invention is obtained by impregnating nickel oxide and molybdenum oxide precursors onto activated carbon, and then by processes such as heating and drying, and calcination under an inert atmosphere. The metal desulfurizing agent includes oxygen-containing functional groups, nitrogen-containing functional groups and metal oxides on the surface of activated carbon.

[0029] Specifically, the metal oxide desulfurizer can be a molybdenum-nickel composite desulfurizer.

[0030] Furthermore, by impregnating activated carbon in a precursor solution containing ammonium molybdate and nickel nitrate, oxygen-containing functional groups and metal oxides are introduced onto the surface of the activated carbon.

[0031] In addition, the metal oxide is a metal sulfide produced after the removal of sulfur compounds, which serves as a hydrogenation catalyst for thiophene-type sulfur.

[0032] See Figure 1 The preparation method of the metal desulfurizer according to an embodiment of the present invention includes the following steps:

[0033] Impregnation (1): Impregnate activated carbon in a precursor solution containing ammonium molybdate and nickel nitrate, and let it stand for 2-4 hours;

[0034] Drying (2): Place the impregnated activated carbon in an oven at 30-60°C for 12-16 hours;

[0035] Calcination (3): Place the dried activated carbon in, for example, a tube furnace, and heat it to 300-500℃ under an inert atmosphere for 3-5 hours. The heating rate is 1-2℃ / min, and the sulfur flow rate of the inert gas is 100-200ml / min to obtain the metal oxide desulfurizer.

[0036] The activated carbon surface of the metal oxide desulfurizer prepared in the embodiments of the present invention has oxygen-containing functional groups, nitrogen-containing functional groups, and metal oxides. In the impregnation (1) step of the preparation process of the present invention, the precursor solution containing ammonium molybdate and nickel nitrate can be prepared by dissolving ammonium heptamolybdate and nickel nitrate hexahydrate in deionized water. When using ammonium heptamolybdate and nickel nitrate hexahydrate dissolved in deionized water as the precursor solution, in some embodiments, the activated carbon is first impregnated in nitric acid solution and then dried in an oven. The dried activated carbon is then impregnated in the precursor solution prepared by dissolving ammonium heptamolybdate and nickel nitrate hexahydrate in deionized water.

[0037] The metal sulfides produced by the metal oxide desulfurizer prepared in this embodiment of the invention after removing H2S can be used as hydrogenation catalysts for thiophene sulfur, which can reduce the cost of pre-sulfurization of hydrogenation catalysts and greatly reduce the environmental pollution problems caused thereby.

[0038] The working sulfur capacity of the metal oxide desulfurizer prepared in this embodiment of the invention was tested using a micro fixed-bed reactor. The specific operating procedure is as follows: An appropriate amount of metal oxide desulfurizer was loaded into a U-shaped tube reactor, wherein the inner diameter of the U-shaped tube reactor was 6 mm and the loading height of the desulfurizer was 2 cm. Before the adsorption desulfurization reaction experiment began, the sample was pre-wetted by purging it with N2 through a water saturator for 1.5 h; subsequently, a mixture of H2S and N2 was mixed by a gas mixer, passed through a water saturator, and then introduced into the U-shaped tube reactor. The H2S concentration at the inlet was 850 mg / m³. 3 The gas flow rate was 100 mL / min, the desulfurization reaction temperature was 30℃, and the desulfurization reaction pressure was 0.1 MPa. The H2S concentration at the outlet was 0.1 mg / m³. 3 Stop the test at the appropriate time and record the exhaust gas concentration at different times.

[0039] The catalytic activity of the metal sulfide desulfurizer prepared in this invention for the hydrogenation of thiophene-based sulfur compounds, such as C4H4S, was tested using a micro fixed-bed reactor after use. The specific operating procedure is as follows: An appropriate amount of metal desulfurizer is loaded into a U-shaped tube reactor, wherein the inner diameter of the U-shaped tube reactor is 6 mm and the loading height of the metal desulfurizer is 1 cm. A mixture of C4H4S, N2, and H2 at the inlet is mixed by a gas mixer before being introduced into the U-shaped tube reactor. The C4H4S concentration at the inlet is 400 mg / m³. 3 The H2 content was 1%, the gas flow rate was 100 mL / min, the hydrogenation catalytic reaction temperature was 350℃, and the desulfurization reaction pressure was 0.1 MPa. The concentrations of sulfur-containing compounds in the exhaust gas were recorded at different times.

[0040] One of the key design features of this invention is the efficient removal of various sulfides, such as H2S, that are inevitably generated in coal gasification technology applications using metal oxide desulfurizers. Furthermore, the metal sulfides generated after the use of the metal oxide desulfurizer serve as hydrogenation catalysts for thiophene-based sulfur compounds, such as C4H4S, thus achieving resource utilization of the waste desulfurizer. Additionally, it avoids the environmental pollution caused by the use of sulfiding agents during the pre-sulfurization process of converting metal oxides into highly hydrogenation-catalyzing metal sulfides, which requires pre-sulfurization treatment before use. Therefore, this invention reduces the use of sulfiding agents, which is of great significance in reducing pollution caused by the pre-sulfurization of HDS catalysts.

[0041] Example 1

[0042] 10g of activated carbon was impregnated in 20mL of nitric acid at 30℃ for 12 hours. The treated activated carbon was then dried in an oven at 110℃ for 6 hours. 1.2g of ammonium heptamolybdate was dissolved in deionized water, and the activated carbon was impregnated in this solution at 30℃ for 12 hours. The impregnated activated carbon was then placed in a tube furnace and calcined at 350℃ for 3 hours under a N2 atmosphere, with a heating rate of 1℃ / min and an N2 flow rate of 100mL / min. Finally, 3.8g of nickel nitrate hexahydrate was weighed and the above steps were repeated to obtain a nickel-molybdenum composite desulfurizing agent.

[0043] In the nickel-molybdenum composite desulfurizer prepared by the above method, the content of nickel oxide is 10 wt.% and the content of molybdenum oxide is 10 wt.%. When the outlet H2S concentration reaches 0.1 mg / m³, 3 At that time, the breakthrough sulfur capacity of the nickel-molybdenum composite desulfurizer was 150 mg / g.

[0044] The main difference between this and other embodiments is that the amount of ammonium heptamolybdate is 1.2g and the amount of nickel nitrate hexahydrate is 3.8g.

[0045] Using the aforementioned nickel-molybdenum composite desulfurizer as a hydrogenation catalyst for C4H4S, the conversion rate of C4H4S can reach 90%.

[0046] Example 2

[0047] 10g of activated carbon was impregnated in 20mL of nitric acid at 30℃ for 12 hours. The treated activated carbon was then dried in an oven at 110℃ for 6 hours. 0.6g of ammonium heptamolybdate was dissolved in deionized water, and the activated carbon was impregnated in the solution at 30℃ for 12 hours. The impregnated activated carbon was then placed in a tube furnace and calcined at 350℃ for 3 hours under a N2 atmosphere, with a heating rate of 1℃ / min and an N2 flow rate of 100mL / min. Finally, 1.9g of nickel nitrate hexahydrate was weighed and the above steps were repeated to obtain a nickel-molybdenum composite desulfurizing agent.

[0048] In the nickel-molybdenum composite desulfurizer prepared by the above method, the content of nickel oxide is 5 wt.% and the content of molybdenum oxide is 5 wt.%. When the outlet H2S concentration reaches 0.1 mg / m³, 3 At that time, the breakthrough sulfur capacity of the nickel-molybdenum composite desulfurizer was 220 mg / g.

[0049] The main difference between this embodiment and other embodiments is that the amount of ammonium heptamolybdate is 0.6g and the amount of nickel nitrate hexahydrate is 1.9g.

[0050] Using the aforementioned nickel-molybdenum composite desulfurizer as a hydrogenation catalyst for C4H4S, the conversion rate of C4H4S can reach 85%.

[0051] Example 3

[0052] 10g of activated carbon was impregnated in 20mL of nitric acid at 30℃ for 12 hours. The treated activated carbon was then dried in an oven at 110℃ for 6 hours. 0.3g of ammonium heptamolybdate was dissolved in deionized water, and the activated carbon was impregnated in the solution at 30℃ for 12 hours. The impregnated activated carbon was then placed in a tube furnace and calcined at 350℃ for 3 hours under a N2 atmosphere, with a heating rate of 1℃ / min and an N2 flow rate of 100mL / min. Finally, 0.95g of nickel nitrate hexahydrate was weighed and the above steps were repeated to obtain a nickel-molybdenum composite desulfurizing agent.

[0053] In the nickel-molybdenum composite desulfurizer prepared by the above method, the content of nickel oxide is 2.5 wt.% and the content of molybdenum oxide is 2.5 wt.%. When the outlet H2S concentration reaches 0.1 mg / m³, 3 At that time, the breakthrough sulfur capacity of the nickel-molybdenum composite desulfurizer was 310 mg / g.

[0054] The main difference between this embodiment and other embodiments is that the amount of ammonium heptamolybdate is 0.3g and the amount of nickel nitrate hexahydrate is 0.95g.

[0055] Using the aforementioned nickel-molybdenum composite desulfurizer as a hydrogenation catalyst for C4H4S, the conversion rate of C4H4S can reach 80%.

[0056] Example 4

[0057] 10g of activated carbon was impregnated in 20mL of nitric acid at 30℃ for 12 hours. The treated activated carbon was then dried in an oven at 110℃ for 6 hours. 0.6g of ammonium heptamolybdate was dissolved in deionized water, and the activated carbon was impregnated in the solution at 30℃ for 12 hours. The impregnated activated carbon was then placed in a tube furnace and calcined at 350℃ for 3 hours under a N2 atmosphere, with a heating rate of 1℃ / min and an N2 flow rate of 100mL / min. Finally, 1.9g of nickel chloride hexahydrate was weighed and the above steps were repeated to obtain a nickel-molybdenum composite desulfurizing agent.

[0058] In the nickel-molybdenum composite desulfurizer prepared by the above method, the content of nickel oxide is 5 wt.% and the content of molybdenum oxide is 5 wt.%. When the outlet H2S concentration reaches 0.1 mg / m³, 3 At that time, the breakthrough sulfur capacity of the nickel-molybdenum composite desulfurizer was 210 mg / g.

[0059] The main difference between this embodiment and other embodiments is that the amount of ammonium heptamolybdate is 0.6g and the amount of nickel nitrate hexahydrate is 1.9g.

[0060] Using the aforementioned nickel-molybdenum composite desulfurizer as a hydrogenation catalyst for C4H4S, the conversion rate of C4H4S can reach 85%.

[0061] Example 5

[0062] 10g of activated carbon was impregnated in 30mL of nitric acid at 30℃ for 12 hours. The treated activated carbon was then dried in an oven at 110℃ for 6 hours. 0.6g of ammonium heptamolybdate was dissolved in deionized water, and the activated carbon was impregnated in the solution at 30℃ for 12 hours. The impregnated activated carbon was then placed in a tube furnace and calcined at 350℃ for 3 hours under a N2 atmosphere, with a heating rate of 1℃ / min and an N2 flow rate of 100mL / min. Finally, 1.9g of nickel nitrate hexahydrate was weighed and the above steps were repeated to obtain a nickel-molybdenum composite desulfurizing agent.

[0063] In the nickel-molybdenum composite desulfurizer prepared by the above method, the content of nickel oxide is 5 wt.% and the content of molybdenum oxide is 5 wt.%. When the outlet H2S concentration reaches 0.1 mg / m³, 3 At that time, the breakthrough sulfur capacity of the nickel-molybdenum composite desulfurizer was 210 mg / g.

[0064] Using the aforementioned nickel-molybdenum composite desulfurizer as a hydrogenation catalyst for C4H4S, the conversion rate of C4H4S can reach 80%.

[0065] A comparison of Examples 2, 4, and 5 with Example 1 shows that doubling the amount of ammonium heptamolybdate and nickel nitrate hexahydrate, or decreasing the amount by half as in Example 3, results in a positive correlation between the breakthrough sulfur capacity and the C4H4S conversion rate at the same outlet H2S concentration. This indicates that increasing the amount of metal desulfurizing agent improves the desulfurization effect and increases the C4H4S conversion rate, while decreasing the amount of metal desulfurizing agent worsens the desulfurization effect and reduces the C4H4S conversion rate.

[0066] This invention's metal oxide desulfurizer is particularly suitable for the clean and efficient utilization of coal, especially for removing various sulfur-containing compounds generated during coal gasification. This reduces equipment and pipeline corrosion, environmental pollution, and even harm to human health caused by the presence of these sulfides. The metal sulfides generated after the use of the metal oxide desulfurizer can be used as hydrogenation catalysts for the hydrogenation desulfurization of thiophene-type sulfur compounds, such as organic sulfur C4H4S. This reduces the secondary pollution caused by solid waste generated by the desulfurization metal oxide desulfurizer, and also reduces the need for pre-sulfurization treatment of the catalyst before use in hydrogenation desulfurization, thus reducing the use of sulfiding agents and lowering the pollution caused by pre-sulfurization.

[0067] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above-described embodiments. Those skilled in the art will understand that changes can be made to these embodiments without departing from the overall concept and spirit of the present invention, and such changes should also be considered to fall within the scope of protection of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. Use of a metal oxide desulfurizer after removal of sulfur compounds, characterized in that, the metal sulfide produced by the metal oxide desulfurizer after removal of sulfur compounds acts as a hydrogenation catalyst for thiophene sulfur, the sulfur compounds include H2S, and the metal oxide desulfurizer removes H2S by oxygen-containing functional groups, nitrogen-containing functional groups on the surface of activated carbon, and metal oxides themselves in an oxygen-free atmosphere, the metal oxide desulfurizer is obtained by sequentially immersing activated carbon in a nitric acid solution, a precursor solution containing ammonium molybdate and nickel nitrate, low-temperature drying at 30-60°C, and calcination in an inert atmosphere, the metal oxide desulfurizer includes oxygen-containing functional groups, nitrogen-containing functional groups on the surface of activated carbon, and supported nickel and molybdenum oxides.

2. Use of the metal oxide desulfurizer according to claim 1 after removal of sulfur compounds, characterized in that, The preparation method of the metal oxide desulfurizer comprises the following steps: immersion (1): immersing activated carbon in a nitric acid solution, then immersing the treated activated carbon in a precursor solution containing ammonium molybdate and nickel nitrate, and standing for 2-4 hours; drying (2): drying the immersed activated carbon at 30-60°C for 12-16 hours; calcination (3): heating the dried activated carbon to 300-500°C in an inert atmosphere, calcining for 3-5 hours, heating rate 1-2°C / min, inert gas flow 100-200 ml / min, to obtain a metal oxide desulfurizer.

3. Use of the metal oxide desulfurizer according to claim 2 after removal of sulfur compounds, characterized in that, in the step of immersion (1), the precursor solution containing ammonium molybdate and nickel nitrate is prepared by dissolving ammonium heptamolybdate and nickel nitrate hexahydrate in deionized water.

4. Use of the metal oxide desulfurizer according to claim 2 after removal of sulfur compounds, characterized in that, in the step of drying (2), the immersed activated carbon is dried in an oven.

5. Use of the metal oxide desulfurizer according to claim 2 after removal of sulfur compounds, characterized in that, in the step of calcination (3), the dried activated carbon is calcined in a tube furnace.

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