Method for removing wax wrapped on surface of waste catalyst in Fischer-Tropsch wax residue

Abstract

The invention discloses a method for removing wax wrapping the surface of a waste catalyst in Fischer-Tropsch residue wax. Belongs to the technical field of nonmetal waste treatment. The method comprises the following steps: mixing a waste catalyst raw material with a compound active agent composed of Tween-80 and SDS, putting the mixture into a constant-temperature oscillation box, carrying out full oscillation treatment to obtain a mixed solution, putting the mixed solution into a centrifugal machine, carrying out centrifugal operation, pouring out supernatant liquid, washing residual solid particles with water, and drying to obtain a catalyst product; according to the method disclosed by the invention, the two surface active agents are matched according to a certain proportion to treat the waste catalyst raw material, so that the Fischer-Tropsch wax residue can be effectively removed and recovered to obtain the wrapping wax on the surface of the waste catalyst, and the loss of the catalyst is less; the problem that wrapping wax on the surface of the catalyst is not easy to separate from the catalyst is solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of non-metal waste treatment, and specifically relates to a method for removing the wax coating on the surface of waste catalysts in Fischer-Tropsch wax residues. Background Art

[0002] The gasification, liquefaction of coal and the production of hydrocarbon compounds are important components of coal chemical industry. The Fischer-Tropsch synthesis technology uses syngas (CO + H2) as raw materials, and under suitable catalysts and reaction conditions, hydrocarbons and oxygen-containing organic compounds are generated. Through this reaction, not only environmentally friendly products such as gasoline, diesel, and paraffin can be obtained, but also high-value-added chemicals such as olefins and oxygen-containing compounds can be obtained, which has good economic efficiency and market prospects.

[0003] A large amount of Fischer-Tropsch synthesis catalysts are required in the Fischer-Tropsch synthesis stage, mainly iron-based catalysts. After the catalyst completes its service cycle, it is discharged from the Fischer-Tropsch synthesis slurry bed and brings out a part of heavy wax, becoming Fischer-Tropsch wax residue. The accumulation of a large amount of Fischer-Tropsch wax residue not only causes waste of resources but also environmental pollution, and it is necessary to classify and recycle it. Currently, magnetic separation is the most convenient and efficient method. However, the surface of the catalyst obtained after magnetic separation still contains a small amount of heavy wax coating. To facilitate the recycling and reuse of the catalyst, it is necessary to remove the wax coating on the surface of the separated catalyst.

[0004] Patent CN202010078658.X discloses a method for recycling Fischer-Tropsch synthesis iron-based catalysts. This method mixes hydrocarbon organic solvents with Fischer-Tropsch wax residue raw materials, and performs extraction under the conditions of heating and stirring to melt and extract the hydrocarbon organic compounds in the wax residue raw materials from the mixture, and then adds carboxylic acid and polar solvents; it is processed under the conditions of heating and stirring to dissolve inorganic substances and small-molecule organic compounds, and heated and dried to obtain dry materials. Finally, the dry materials are mixed with magnetic separation media and then magnetically separated to recover iron-based catalysts. However, the method of using organic solvent extraction requires a large amount of solvent. Due to the high adsorption degree and tight bonding of the wax coating on the catalyst surface, the separation efficiency of wax and catalyst is not high. Summary of the Invention

[0005] The present invention overcomes the deficiencies of the prior art. The present invention proposes a method for removing the wax coating on the surface of waste catalysts in Fischer-Tropsch wax residues; it solves the problem that the wax coating on the catalyst surface is not easily separated from the catalyst.

[0006] The present invention is realized by the following technical solutions: A method for removing the wax coating on the surface of waste catalysts in Fischer-Tropsch wax residues, comprising the following steps: 1) Mix the waste catalyst raw material and the compound surfactant at a liquid-solid ratio of 14-16:1 to form a mixed solution, and obtain a mixed suspension after sufficient shaking treatment; the compound surfactant is a compound of Tween-80 and SDS, and the mass ratio of Tween-80:SDS = 3-4:1; The surface of the waste catalyst raw material is coated with 7%-15% heavy hydrocarbon wax.

[0007] 2) Centrifuge the mixed suspension to obtain a layered mixture; 3) Pour out the upper emulsion in the layered mixture, and wash and dry the remaining solid to obtain the catalyst.

[0008] Preferably, the mass ratio of the compound surfactant is Tween-80:SDS = 3:1.

[0009] Preferably, the concentration of the compound surfactant is 11-13 g / L.

[0010] Preferably, the concentration of the compound surfactant is 12 g / L.

[0011] More preferably, the liquid-solid ratio of the waste residue wax raw material and the compound surfactant is 15:1.

[0012] Preferably, the sufficient shaking in step 1) is to place the mixed solution in a constant temperature shaking incubator for treatment.

[0013] More preferably, the treatment temperature of the constant temperature shaking incubator is 35°C.

[0014] Temperature plays a direct role in the treatment effect of the medicament. When the treatment temperature is too low, the bonding degree between the wax and the catalyst is relatively high, and the activity of the medicament is relatively low. However, the temperature should not be too high, otherwise it will cause the inactivation of the medicament and the instability of the emulsion system. For the constant temperature shaking operation, the operation time should be not less than 1 hour.

[0015] Preferably, the rotation speed of the centrifugation operation in step 2) is 4000-6000 rpm, and the time is 5-7 min.

[0016] After the compound surfactant fully emulsifies the wax on the catalyst surface, it needs to be centrifuged sufficiently in a centrifuge to separate the emulsified wax / medicament mixture from the catalyst solid. However, the centrifugation operation time should not be too long, otherwise it will cause the demulsification of the emulsion system and the wax will reattach to the surface of the catalyst particles.

[0017] More preferably, the rotation speed of the centrifugation operation in step 2) is 5000 rpm, and the time is 6 min.

[0018] Preferably, in step (3), the cleaning is performed by water washing. To prevent the pure catalyst from being further oxidized by air and affecting the recycling of the catalyst, the drying operation in step (3) can be carried out using a commonly used vacuum dryer in the art.

[0019] The mechanism of the present invention is as follows: The compound surfactant used in the present invention is a compound of Tween-80 and SDS. Tween-80 and SDS are a non-ionic surfactant and an ionic surfactant respectively. The long-chain structure of Tween-80 and the polar head group (hydrophilicity) of SDS act together to enhance the emulsification effect of wax and the stability of the emulsified state. When the mass ratio of the compound surfactant of Tween-80 and SDS is Tween-80:SDS = 3:1, the wax removal rate can be significantly improved.

[0020] The removal of wax wrapped on the surface of the waste catalyst is related to the amount of the agent. Under certain concentration and compound ratio conditions, the mass ratio of the agent amount to the mass of the waste catalyst raw material is called the liquid-solid ratio. The optimal liquid-solid ratio for mixing the waste residue wax raw material and the compound surfactant is 15:1.

[0021] The beneficial effects of the present invention compared with the prior art are as follows: (1) The present invention utilizes the long-chain structure of Tween-80 and the hydrophilic group characteristics of SDS to enhance the emulsification and stability of the whole system. Compared with the extraction with hydrocarbon organic solvents, the separation process of the catalyst and the heavy wax is simpler and the separation effect is better.

[0022] (2) Compared with the existing extraction technology, the present invention has low separation cost, low energy consumption during the operation process, the method is safe and reliable, and has strong continuous processing ability during the industrial production process.

[0023] (3) By using the method of the present invention to remove the wax wrapped on the surface of the catalyst, the surface wax removal rate can reach more than 80%. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a flowchart of the operation of the method for removing the wax wrapped on the surface of the waste catalyst in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0025] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with the embodiments and the drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. The technical solutions of the present invention will be described in detail below in conjunction with the embodiments and the drawings, but the protection scope is not limited by this.

[0026] Example 1 This embodiment provides a method for removing the wax coating on the surface of waste catalysts in Fischer-Tropsch wax residues, specifically including the following steps: (1) 15% of hydrocarbon heavy wax is coated on the surface of the waste catalyst raw material; the waste catalyst raw material and the compound surfactant are mixed at a liquid-solid ratio of 15:1 to form a mixed solution. The compound surfactant is a mixture of Tween-80 and SDS, with a mass ratio of Tween-80:SDS = 3:1 and a concentration of the compound surfactant of 12 g / L. The mixed solution is placed in a constant-temperature shaking incubator for shaking operation at a temperature of 35°C for 2 hours to obtain a mixed suspension; (2) The mixed suspension obtained in step (1) above is placed in a centrifuge for centrifugation for 6 minutes at a rotation speed of 5000 rpm; a layered mixture is obtained; (3) Pour out the upper emulsion in the layered mixture, wash and dry the remaining solid to obtain a pure catalyst. The drying is carried out using a vacuum dryer; and the wax content on the surface of the catalyst is measured.

[0027] Example 2 This embodiment provides a method for removing the wax coating on the surface of waste catalysts in Fischer-Tropsch wax residues, specifically including the following steps: (1) 15% of hydrocarbon heavy wax is coated on the surface of the waste catalyst raw material; the waste catalyst raw material and the compound surfactant are mixed at a liquid-solid ratio of 15:1. The compound surfactant is a mixture of Tween-80 and SDS, with a mass ratio of Tween-80:SDS = 3:1 and a concentration of the compound surfactant of 10 g / L. The mixed solution is placed in a constant-temperature shaking incubator for shaking operation at a temperature of 35°C for 2 hours to obtain a mixed suspension; (2) The mixed suspension obtained in step (1) above is placed in a centrifuge for centrifugation for 6 minutes at a rotation speed of 5000 rpm; a layered mixture is obtained; (3) Pour out the upper emulsion in the layered mixture, wash and dry the remaining solid to obtain a pure catalyst. The drying is carried out using a vacuum dryer; and the wax content on the surface of the catalyst is measured.

[0028] Example 3 This embodiment provides a method for removing the wax coating on the surface of waste catalysts in Fischer-Tropsch wax residues, specifically including the following steps: (1) 15% of hydrocarbon heavy wax is coated on the surface of the waste catalyst raw material; the waste catalyst raw material and the compound surfactant are mixed at a liquid-solid ratio of 15:1. The compound surfactant is a mixture of Tween-80 and SDS, with a ratio of Tween-80:SDS = 3:1 and a concentration of 11 g / L. The mixed solution is placed in a constant-temperature shaking incubator for shaking operation at a temperature of 35°C for 2 hours to obtain a mixed suspension; (2) Place the mixed suspension obtained in the above step (1) in a centrifuge for centrifugation. The centrifugation time is 6 min, and the rotation speed of the centrifugation operation is 5000 rpm; a layered mixture is obtained. (3) Pour out the upper emulsion in the layered mixture, wash and dry the remaining solid to obtain a pure catalyst. The drying is carried out using a vacuum dryer; and measure the wax content on the surface of the catalyst.

[0029] Example 4 This example proposes a method for removing the wax wrapped on the surface of the waste catalyst in the Fischer-Tropsch wax residue, specifically the following steps: (1) The surface of the waste catalyst raw material is wrapped with 15% hydrocarbon heavy wax; the waste catalyst raw material is mixed with the compound surfactant according to a liquid-solid ratio of 15:1. The compound surfactant is a compound of Tween-80 and SDS, and the mass ratio is Tween-80:SDS = 3:1, with a concentration of 12 g / L. Place the mixed solution in a constant temperature shaking incubator for shaking operation. The temperature is 40 °C, and the shaking time is 2 hours to obtain a mixed suspension. (2) Place the mixed suspension obtained in the above step (1) in a centrifuge for centrifugation. The rotation speed of the centrifugation operation is 5000 rpm, and the centrifugation time is 6 min to obtain a layered mixture. (3) Pour out the upper emulsion in the layered mixture, wash and dry the remaining solid to obtain a pure catalyst. The drying is carried out using a vacuum dryer; and measure the wax content on the surface of the catalyst.

[0030] Example 5 This example proposes a method for removing the wax wrapped on the surface of the waste catalyst in the Fischer-Tropsch wax residue, specifically the following steps: (1) The surface of the waste catalyst raw material is wrapped with 10% hydrocarbon heavy wax; the waste catalyst raw material is mixed with the compound surfactant according to a liquid-solid ratio of 14:1. The compound surfactant is a compound of Tween-80 and SDS, and the mass ratio is Tween-80:SDS = 4:1, with a concentration of 13 g / L. Place the mixed solution in a constant temperature shaking incubator for shaking operation. The temperature is 30 °C, and the shaking time is 2 hours to obtain a mixed suspension. (2) Place the mixed suspension obtained in the above step (1) in a centrifuge for centrifugation. The centrifugation time is 7 min, and the rotation speed of the centrifugation operation is 6000 rpm to obtain a layered mixture. (3) Pour out the upper emulsion in the layered mixture, wash and dry the remaining solid to obtain a pure catalyst. The drying is carried out using a vacuum dryer.

[0031] Example 6 This embodiment provides a method for removing the wax coating on the surface of waste catalysts in Fischer-Tropsch wax residues, specifically including the following steps: (1) The surface of the waste catalyst raw material is coated with 7% hydrocarbon heavy wax; the waste catalyst raw material is mixed with the compound surfactant according to a liquid-solid ratio of 16:1. The compound surfactant is a compound of Tween-80 and SDS, and the mass ratio is Tween-80:SDS = 3.5:1, with a concentration of 11 g / L. The mixed solution is placed in a constant-temperature shaker for shaking operation at a temperature of 30°C for 2 hours to obtain a mixed suspension; (2) The mixed suspension obtained in the above step (1) is placed in a centrifuge for centrifugation for 5 minutes at a rotational speed of 4000 rpm; a layered mixture is obtained; (3) Pour out the upper emulsion in the layered mixture, and wash and dry the remaining solid to obtain a pure catalyst. Vacuum drying is used for drying.

[0032] Comparative Example 1 This comparative example provides a method for removing the wax coating on the surface of waste catalysts in Fischer-Tropsch wax residues, specifically including the following steps: (1) The surface of the waste catalyst raw material is coated with 15% hydrocarbon heavy wax; the waste catalyst raw material is mixed with the compound surfactant according to a liquid-solid ratio of 5:1. The compound surfactant is a compound of Tween-80 and SDS, with a mass ratio of Tween-80:SDS = 3:1, and the concentration of the compound surfactant is 12 g / L. The mixed solution is placed in a constant-temperature shaker for shaking operation at a temperature of 35°C for 2 hours to obtain a mixed suspension; (2) The mixed suspension obtained in the above step (1) is placed in a centrifuge for centrifugation at a rotational speed of 5000 rpm for 6 minutes to obtain a layered mixture; (3) Pour out the upper emulsion in the layered mixture, and wash and dry the remaining solid to obtain a pure catalyst, and measure the wax content on the surface of the catalyst.

[0033] Comparative Example 2 This comparative example provides a method for removing the wax coating on the surface of waste catalysts in Fischer-Tropsch wax residues, specifically including the following steps: (1) The surface of the waste catalyst raw material is coated with 15% hydrocarbon heavy wax; the waste catalyst raw material is mixed with the compound surfactant according to a liquid-solid ratio of 10:1. The compound surfactant is a compound of Tween-80 and SDS, and the mass ratio is Tween-80:SDS = 3:1, with a concentration of 12 g / L. The mixed solution is placed in a constant-temperature shaker for shaking operation at a temperature of 35°C for 2 hours to obtain a mixed suspension; (2) Place the mixed suspension obtained in the above step (1) in a centrifuge for centrifugation. The centrifugation time is 6 min, and the rotation speed of the centrifugation operation is 5000 rpm; a layered mixture is obtained. (3) Pour out the upper emulsion in the layered mixture, wash and dry the remaining solid to obtain a pure catalyst, and measure the wax content on the surface of the catalyst.

[0034] Comparative Example 3 This comparative example presents a method for removing the wax wrapped on the surface of the waste catalyst in Fischer-Tropsch wax residue, specifically the following steps: (1) 15% of hydrocarbon heavy wax is wrapped on the surface of the waste catalyst raw material; the waste catalyst raw material and the hydrocarbon agent n-heptane are mixed at a liquid-solid ratio of 15:1. The mixed liquid is placed in a constant-temperature shaking incubator for shaking operation. The temperature is 35 °C, and the shaking time is 2 hours to obtain a mixed suspension. (2) Place the mixed suspension obtained in the above step (1) in a centrifuge for centrifugation. The centrifugation time is 6 min, and the rotation speed of the centrifugation operation is 5000 rpm; a layered mixture is obtained. (3) Pour out the upper emulsion in the layered mixture, wash and dry the remaining solid to obtain a pure catalyst, and measure the wax content on the surface of the catalyst.

[0035] The wax removal rates of Examples 1-4 and Comparative Examples 1-3 are shown in Table 1.

[0036] It can be seen from Table 1 that in Comparative Example 3, ordinary hydrocarbon organic matter was used to extract the waste catalyst raw material, and the configured active agent was not used. Its wax removal rate was significantly lower than that of Examples 1-4; and when the liquid-solid ratio was 15:1, the compounding concentration was 12 g / L, and the shaking temperature was 35 °C, the wax removal rate could reach 81.4%.

[0037] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific embodiments of the present invention are limited to this. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the premise of the present invention, several simple deductions or substitutions can still be made, which should all be regarded as belonging to the patent protection scope determined by the claims submitted by the present invention.

Claims

1. A method for removing wax coated on the surface of waste catalyst in Fischer-Tropsch slag wax, characterized in that: The following steps are involved: 1) Mixing the waste catalyst raw material and the composite active agent at a liquid-solid ratio of 14-16:1 to prepare a mixed solution, and fully shaking the mixture at a temperature of 30°C-40°C to obtain a mixed suspension; the composite active agent is a compound of Tween-80 and SDS, and the mass ratio of Tween-80:SDS=3-4:1; 2) centrifuging the mixed suspension to obtain a layered mixture; 3) Pour out the upper emulsion from the layered mixture, and wash and dry the remaining solid to obtain the catalyst.

2. The method for removing wax coated on the surface of waste catalyst in Fischer-Tropsch slag wax according to claim 1, characterized in that: The mass ratio of the compound active agent is Tween-80:SDS=3:

1.

3. A method for removing wax coated on the surface of waste catalyst in Fischer-Tropsch slag wax according to claim 2, characterized in that: The concentration of the compound active agent is 11-13 g / L.

4. The method for removing wax coated on the surface of waste catalyst in Fischer-Tropsch slag wax according to claim 3, characterized in that: The concentration of the compound active agent is 12 g / L.

5. The method for removing wax coated on the surface of waste catalyst in Fischer-Tropsch slag wax according to claim 4, characterized in that: The liquid-to-solid ratio of the waste wax raw material and the compounded active agent is 15:

1.

6. The method for removing wax coated on the surface of waste catalyst in Fischer-Tropsch slag wax according to claim 1, characterized in that: The sufficient shaking in step 1) is to place the mixed solution in a constant temperature shaking box for treatment; the treatment temperature of the constant temperature shaking box is 35°C.

7. A method for removing wax coated on the surface of waste catalyst in Fischer-Tropsch slag wax according to claim 6, characterized in that: The shaking treatment time is ≥1h.

8. The method for removing wax coated on the surface of waste catalyst in Fischer-Tropsch slag wax according to claim 1, characterized in that: The centrifugal operation in step 2) is performed at a speed of 4000-6000 rpm and for 5-7 min.

9. A method for removing wax coated on the surface of waste catalyst in Fischer-Tropsch slag wax according to claim 8, characterized in that: The centrifugal operation in step 2) is performed at a speed of 5000 rpm and a time of 6 min.

10. The method for removing wax coated on the surface of waste catalyst in Fischer-Tropsch slag wax according to claim 1, characterized in that: In the step 3), the washing is performed by water washing.

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