A catalyst for wet oxidation of oil refining alkali residue and a preparation method thereof
By preparing a wet oxidation catalyst for oil refining alkali residue using modified activated carbon, the problems of high cost of precious metal catalysts and easy loss of non-precious metals were solved. This achieved efficient degradation of organic matter and sulfur-containing compounds in oil refining alkali residue, reduced COD of wastewater, and the catalyst was not easily deactivated.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2023-10-26
- Publication Date
- 2026-05-26
AI Technical Summary
In existing oil refining alkali residue treatment processes, precious metal catalysts are costly and prone to deactivation, while non-precious metal catalysts are prone to loss of active metals, resulting in high energy consumption and high treatment costs in wet oxidation methods, and the catalyst preparation process is complex.
Modified activated carbon is used as a wet oxidation catalyst for oil refining alkali residue. By mixing and stirring it with a strong alkali solution under specific temperature and pressure conditions, functional groups generated during oxidation are formed, which serve as catalytic active centers, thus avoiding the dissolution and deactivation of active components.
It achieves effective degradation of organic matter and sulfur-containing compounds in oil refining alkali residue under high temperature and high pressure, reduces COD in wastewater, the catalyst is not easily deactivated, and the preparation process is simple and low in cost.
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Figure CN119897085B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of catalysts, and more particularly to a wet oxidation catalyst for oil refining alkali residue and its preparation method. Background Technology
[0002] The waste alkaline liquid produced after washing catalytic cracking gasoline and liquid hydrocarbons in gas separation units with alkaline solution is collectively referred to as alkaline residue. It contains components such as floating oil, sulfides, and phenols, and has a complex composition. Its COD is as high as hundreds of thousands, making it one of the most difficult waste liquids to treat in the oil refining and chemical industry.
[0003] Currently, the main process for treating refinery alkali residue is wet oxidation (WAO). WAO oxidizes sulfides in the alkali residue to form sulfates under relatively high temperature and medium-high pressure conditions, and degrades organic matter into carbon dioxide and water. However, this process requires high temperature and pressure, resulting in high energy consumption and processing costs. To reduce energy consumption and processing costs, catalytic wet oxidation, which introduces catalysts into the traditional wet oxidation system, is gaining increasing attention. This method can lower the required temperature and pressure and improve reaction efficiency.
[0004] Current wet oxidation catalysts are mainly metal catalysts, with complex preparation processes requiring multiple steps such as impregnation and calcination. They primarily use precious metal catalysts such as platinum, palladium, rhodium, iridium, and ruthenium, due to their superior performance, high catalytic activity, and strong acid and alkali resistance. However, their high cost severely limits their application. Non-precious metal catalyst technologies are still immature, often suffering from the problem of active metal loss leading to poisoning and deactivation, requiring further research and improvement. Summary of the Invention
[0005] This invention provides a wet oxidation catalyst for oil refining alkali residue and its preparation method. Modified activated carbon is used as the wet oxidation catalyst for oil refining alkali residue. There is no problem of active component leaching, and the catalyst is not easily deactivated, resulting in high catalytic efficiency for wet oxidation of oil refining alkali residue.
[0006] To address the aforementioned technical problems, one objective of this invention is to provide a method for preparing a wet oxidation catalyst for oil refining alkali residue, comprising the following steps:
[0007] S1. Dissolve activated carbon in a solution to form a mixture;
[0008] S2. After stirring the mixture under an oxygen atmosphere of 0.5MPa-5MPa and a temperature of 200℃-260℃, the activated carbon is filtered out, and the filter residue is dried to obtain the catalyst.
[0009] As a preferred embodiment, in S1, the solution is water or a strong alkaline solution with a mass fraction of 0.01wt%-1wt%.
[0010] As a preferred embodiment, the strong base is NaOH or KOH.
[0011] As a preferred embodiment, in S1, 30 mL to 60 mL of solution is added for every 1 g of activated carbon.
[0012] As a preferred embodiment, in S1, the activated carbon is at least one of coal-derived activated carbon, coconut shell activated carbon, and fruit shell activated carbon.
[0013] As a preferred option, in S2, the stirring reaction time is 1h-8h.
[0014] As a preferred embodiment, in S2, the filter residue drying method is natural drying, oven drying, vacuum drying, or freeze drying.
[0015] As a preferred option, in S2, the drying temperature is below 250°C.
[0016] To address the aforementioned technical problems, a second objective of this invention is to provide a method for preparing a wet oxidation catalyst for oil refining alkali residue.
[0017] To solve the above-mentioned technical problems, the third objective of this invention is to provide a method for treating oil refining alkali residue, which uses a wet oxidation catalyst for oil refining alkali residue and includes the following steps: placing the wet oxidation catalyst for oil refining alkali residue and the oil refining alkali residue in a high-pressure reactor and reacting for more than 1 hour under oxygen environment and temperature of 180℃-240℃ and pressure of 1MPa-4MPa.
[0018] As a preferred embodiment, the COD of the oil refining alkali residue is below 10000 mg / L, and 0.2g-1g of the oil refining alkali residue wet oxidation catalyst is added for every 100mL of the oil refining alkali residue.
[0019] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:
[0020] 1. This application uses modified activated carbon as a wet oxidation catalyst for oil refining alkali residue. It does not use metal as an active component. As a non-supported catalyst, modified activated carbon does not have the problem of active component leaching. Moreover, the active center of the catalyst is the functional group generated by oxidation. The conditions of the wet oxidation reaction of oil refining alkali residue are similar to those of activated carbon modification, which will not destroy the functional groups of the catalyst and make the catalyst less prone to deactivation.
[0021] 2. In the wet oxidation process, the catalyst of this application degrades organic matter and sulfur-containing compounds in the oil refining residue into CO2, H2O and SO4 under high temperature and high pressure conditions. 2- This achieves the effect of reducing COD in wastewater, and the catalyst can be produced through a simple process, which is conducive to expanding production and application. Attached Figure Description
[0022] Figure 1 : These are COD statistics of the oil refining alkali residue during the reaction for 4 hours in Example 2 and Comparative Examples 2 and 4 of this invention (Note: Catalyst 2 - Example 2; Coconut shell activated carbon - Comparative Example 2; Blank - Comparative Example 4). Detailed Implementation
[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0024] Preparation Example 1
[0025] A wet oxidation catalyst for oil refining alkaline residue includes the following preparation steps:
[0026] S1. Weigh 4g of coal-derived activated carbon and dissolve it in 150ml of water to form a mixture;
[0027] S2. After stirring the mixture in an oxygen atmosphere of 0.5 MPa and at 260°C for 2 hours, the activated carbon was filtered out. The filter residue was then naturally dried for 24 hours to obtain the catalyst.
[0028] Preparation Example 2
[0029] A wet oxidation catalyst for oil refining alkaline residue includes the following preparation steps:
[0030] S1. Weigh 4g of coconut shell activated carbon and dissolve it in 150ml of 0.01% NaOH solution to form a mixture;
[0031] S2. After stirring the mixture in an oxygen atmosphere of 0.5 MPa and at 200°C for 4 hours, the activated carbon was filtered out. The filter residue was dried in an air atmosphere at 100°C for 16 hours to obtain the catalyst.
[0032] Preparation Example 3
[0033] A wet oxidation catalyst for oil refining alkaline residue includes the following preparation steps:
[0034] S1. Weigh 4g of coconut shell activated carbon and dissolve it in 150ml of 0.01% NaOH solution to form a mixture;
[0035] S2. After stirring the mixture at 5MPa oxygen atmosphere and 200℃ for 4 hours, the activated carbon was filtered out. The filter residue was dried in air at 100℃ for 16 hours to obtain the catalyst.
[0036] Preparation Example 4
[0037] A wet oxidation catalyst for oil refining alkaline residue includes the following preparation steps:
[0038] S1. Weigh 4g of fruit shell activated carbon and dissolve it in 150ml of 0.1% NaOH solution to form a mixture;
[0039] S2. After stirring the mixture in an oxygen atmosphere of 0.5 MPa and at 240°C for 8 hours, the activated carbon was filtered out. The filter residue was dried in air at 120°C for 8 hours to obtain the catalyst.
[0040] Preparation Example 5
[0041] A wet oxidation catalyst for oil refining alkaline residue includes the following preparation steps:
[0042] S1. Weigh 4g of coal-derived activated carbon and dissolve it in 150ml of 0.5% NaOH solution to form a mixture;
[0043] S2. After stirring the mixture in an oxygen atmosphere of 0.5 MPa and at 260°C for 2 hours, the activated carbon was filtered out. The filter residue was then naturally dried for 24 hours to obtain the catalyst.
[0044] Preparation Example 6
[0045] A wet oxidation catalyst for oil refining alkaline residue includes the following preparation steps:
[0046] S1. Weigh 4g of coal-derived activated carbon and dissolve it in 150ml of 1% NaOH solution to form a mixture;
[0047] S2. After stirring the mixture in an oxygen atmosphere of 0.5 MPa and at 260°C for 2 hours, the activated carbon was filtered out. The filter residue was then naturally dried for 24 hours to obtain the catalyst.
[0048] Comparative Preparation Example 1
[0049] A wet oxidation catalyst for oil refining alkaline residue includes the following preparation steps:
[0050] S1. Weigh 4g of coal-derived activated carbon and dissolve it in 150ml of water to form a mixture;
[0051] S2. After stirring the mixture in an oxygen atmosphere of 0.02 MPa and at 180°C for 2 hours, the activated carbon was filtered out. The filter residue was then naturally dried for 24 hours to obtain the catalyst.
[0052] Example 1
[0053] A method for treating oil refining alkali residue includes the following steps:
[0054] 0.5 g of the catalyst from Preparation Example 1 and 150 mL of diluted oil refining alkali residue (COD of 7500 mg / L after dilution) were placed together in a high-pressure reactor and reacted for 2 hours under oxygen conditions and at a high temperature of 200°C and a high pressure of 4 MPa, so that the organic matter and sulfur-containing compounds in the oil refining alkali residue were degraded into CO2, H2O and SO4. 2- This achieves the effect of reducing the COD of wastewater. The COD (chemical oxygen demand) of the alkaline residue after the reaction was tested, and the results are shown in Table 1 below.
[0055] Example 2
[0056] A method for treating oil refining alkali residue includes the following steps:
[0057] 0.5 g of the catalyst from Preparation Example 2 and 150 mL of diluted oil refining alkali residue (COD of 7500 mg / L after dilution) were placed together in a high-pressure reactor and reacted for 2 hours under oxygen conditions and at a high temperature of 200°C and a high pressure of 4 MPa, so that the organic matter and sulfur-containing compounds in the oil refining alkali residue were degraded into CO2, H2O and SO4. 2- This achieves the effect of reducing the COD of wastewater. The COD of the alkaline residue after the reaction was detected, and the results are shown in Table 1 below. Figure 1 As shown.
[0058] Example 3
[0059] A method for treating oil refining alkali residue includes the following steps:
[0060] 0.5 g of the catalyst from Preparation Example 3 and 150 mL of diluted oil refining alkali residue (COD of 7500 mg / L after dilution) were placed together in a high-pressure reactor and reacted for 2 hours under oxygen conditions and at a high temperature of 200°C and a high pressure of 4 MPa, so that the organic matter and sulfur-containing compounds in the oil refining alkali residue were degraded into CO2, H2O and SO4. 2- This achieves the effect of reducing the COD of wastewater. The COD of the alkaline residue after the reaction was detected, and the results are shown in Table 1 below.
[0061] Example 4
[0062] A method for treating oil refining alkali residue includes the following steps:
[0063] 0.5 g of the catalyst from Preparation Example 4 and 150 mL of diluted oil refining alkali residue (COD of 7500 mg / L after dilution) were placed together in a high-pressure reactor and reacted for 2 hours under oxygen conditions and at a high temperature of 200°C and a high pressure of 4 MPa, so that the organic matter and sulfur-containing compounds in the oil refining alkali residue were degraded into CO2, H2O and SO4. 2- This achieves the effect of reducing the COD of wastewater. The COD of the alkaline residue after the reaction was detected, and the results are shown in Table 1 below.
[0064] Example 5
[0065] A method for treating oil refining alkali residue includes the following steps:
[0066] 0.5 g of the catalyst from Preparation Example 5 and 150 mL of diluted oil refining alkali residue (COD of 7500 mg / L after dilution) were placed together in a high-pressure reactor and reacted for 2 hours under oxygen conditions and at a high temperature of 200°C and a high pressure of 4 MPa, so that the organic matter and sulfur-containing compounds in the oil refining alkali residue were degraded into CO2, H2O and SO4. 2- This achieves the effect of reducing the COD of wastewater. The COD of the alkaline residue after the reaction was detected, and the results are shown in Table 1 below.
[0067] Example 6
[0068] A method for treating oil refining alkali residue includes the following steps:
[0069] 0.5 g of the catalyst from Preparation Example 6 and 150 mL of diluted oil refining alkali residue (COD of 7500 mg / L after dilution) were placed together in a high-pressure reactor and reacted for 2 hours under oxygen conditions and at a high temperature of 200°C and a high pressure of 4 MPa, so that the organic matter and sulfur-containing compounds in the oil refining alkali residue were degraded into CO2, H2O and SO4. 2- This achieves the effect of reducing the COD of wastewater. The COD of the alkaline residue after the reaction was detected, and the results are shown in Table 1 below.
[0070] Comparative Example 1
[0071] A method for treating oil refining alkali residue includes the following steps:
[0072] 0.5g of coal-derived activated carbon and 150mL of diluted oil refining alkali residue (COD of 7500mg / L after dilution) were placed together in a high-pressure reactor and reacted for 2 hours under oxygen conditions and at a high temperature of 200℃ and a high pressure of 4MPa. This process degraded the organic matter and sulfur-containing compounds in the oil refining alkali residue into CO2, H2O and SO4. 2- This achieves the effect of reducing the COD of wastewater. The COD of the alkaline residue after the reaction was detected, and the results are shown in Table 1 below.
[0073] Comparative Example 2
[0074] A method for treating oil refining alkali residue includes the following steps:
[0075] 0.5g of coconut shell activated carbon and 150mL of diluted oil refining alkali residue (COD of 7500mg / L after dilution) were placed together in a high-pressure reactor and reacted for 2 hours under oxygen conditions and at a high temperature of 200℃ and a high pressure of 4MPa. This process degraded the organic matter and sulfur-containing compounds in the oil refining alkali residue into CO2, H2O and SO4. 2- This achieves the effect of reducing the COD of wastewater. The COD of the alkaline residue after the reaction was detected, and the results are shown in Table 1 below. Figure 1 As shown.
[0076] Comparative Example 3
[0077] A method for treating oil refining alkali residue includes the following steps:
[0078] 0.5g of coconut shell activated carbon and 150mL of diluted oil refining alkali residue (COD of 7500mg / L after dilution) were placed together in a high-pressure reactor and reacted for 2 hours under oxygen conditions and at a high temperature of 200℃ and a high pressure of 4MPa. This process degraded the organic matter and sulfur-containing compounds in the oil refining alkali residue into CO2, H2O and SO4. 2- This achieves the effect of reducing the COD of wastewater. The COD of the alkaline residue after the reaction was detected, and the results are shown in Table 1 below.
[0079] Comparative Example 4
[0080] A method for treating oil refining alkali residue includes the following steps:
[0081] 150 mL of diluted oil refining alkali residue (COD of 7500 mg / L after dilution) was placed in a high-pressure reactor and reacted for 2 hours under oxygen conditions and at a high temperature of 200°C and a high pressure of 4 MPa. This process degraded the organic matter and sulfur-containing compounds in the oil refining alkali residue into CO2, H2O, and SO4. 2- This achieves the effect of reducing the COD of wastewater. The COD of the alkaline residue after the reaction was detected, and the results are shown in Table 1 below. Figure 1 As shown.
[0082] Comparative Example 5
[0083] A method for treating oil refining alkali residue includes the following steps:
[0084] 0.5 g of the catalyst from Comparative Preparation Example 1 and 150 mL of diluted oil refining alkali residue (COD of 7500 mg / L after dilution) were placed together in a high-pressure reactor and reacted for 2 hours under oxygen conditions and at a high temperature of 200°C and a high pressure of 4 MPa, so that the organic matter and sulfur-containing compounds in the oil refining alkali residue were degraded into CO2, H2O and SO4. 2- This achieves the effect of reducing the COD of wastewater. The COD of the alkaline residue after the reaction was detected, and the results are shown in Table 1 below.
[0085] Table 1 - COD results of alkaline residue after reaction in the embodiments and comparative examples of this application.
[0086]
[0087]
[0088] A comparison of the COD results of the alkaline residue after the wet oxidation reaction in Examples 1 and 5-6 in Table 1 shows that the catalyst in Example 1 was modified using an aqueous solution under specific temperature and pressure conditions during preparation, while the catalysts in Examples 4-5 were treated with a strong alkaline solution during preparation. During the hydrothermal process, sodium ions act as a catalyst, promoting the formation of oxygen-containing functional groups and improving catalyst activity.
[0089] By comparing the COD results of the alkaline residue after wet oxidation reaction in Example 1 and Comparative Examples 1 and 5 in Table 1, it can be seen that, compared with Example 1, the catalyst of Comparative Example 5 has a very poor modification effect on coal-based activated carbon due to the low temperature and pressure of its modification process. Its catalytic efficiency is basically the same as that of the unmodified coal-based activated carbon in Comparative Example 1. In addition, if the temperature and pressure of catalyst modification are too high, the coal-based activated carbon will be oxidized, destroyed and crushed. The activated carbon particles cannot be recovered and are not suitable as a heterogeneous catalyst.
[0090] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.
Claims
1. A method for preparing a catalyst for wet oxidation of refinery caustic sludge, characterized by, Includes the following steps: S1. Dissolve activated carbon in a solution to form a mixture; S2. After stirring the mixture under an oxygen atmosphere of 0.5MPa-5MPa and a temperature of 200℃-260℃, the activated carbon is filtered out, and the filter residue is dried to obtain the catalyst. In S1, the solution is water or a strong alkaline solution with a mass fraction of 0.01wt%-1wt%.
2. The method of claim 1, wherein the catalyst is prepared by the steps of: (a) mixing the alkali metal salt with the transition metal salt; (b) adding the mixture to the aqueous solution; (c) adding the acid to the mixture; and (d) stirring the mixture until the catalyst is formed. In S1, 30 mL to 60 mL of solution is added for every 1 g of activated carbon.
3. The method for preparing a wet oxidation catalyst for oil refining alkali residue as described in claim 1, characterized in that, In S1, the activated carbon is at least one of coal-derived activated carbon, coconut shell activated carbon, and fruit shell activated carbon.
4. The method for preparing a wet oxidation catalyst for oil refining alkali residue as described in claim 1, characterized in that, In S2, the stirring reaction time is 1h-8h.
5. The method for preparing a wet oxidation catalyst for oil refining alkali residue as described in claim 1, characterized in that, In S2, the filter residue is dried by natural drying, baking, vacuum drying, or freeze drying.
6. The method for preparing a wet oxidation catalyst for oil refining alkali residue as described in claim 1, characterized in that, In S2, the drying temperature is below 250°C.
7. A method for treating oil refining alkali residue, characterized in that, The wet oxidation catalyst for oil refining alkali residue prepared by any one of the preparation methods described in claims 1-6 includes the following steps: placing the wet oxidation catalyst for oil refining alkali residue and oil refining alkali residue in a high-pressure reactor and reacting for more than 1 hour under oxygen environment and temperature of 180℃-240℃ and pressure of 1MPa-4MPa.
8. The method for treating oil refining alkali residue as described in claim 7, characterized in that, The COD of the oil refining alkali residue is below 10000 mg / L, and 0.2g-1g of the oil refining alkali residue wet oxidation catalyst is added for every 100mL of the oil refining alkali residue.