Modified clay, method for preparing the same, and method for removing color of oil

Abstract

This invention relates to the field of oil decolorization and refining technology, and discloses modified clay and its preparation method, as well as a method for removing color from oil products. The preparation method of modified clay includes: (1) preheating the clay under an inert atmosphere to obtain activated clay; (2) subjecting the activated clay and an acidic solution to a first heating treatment and a drying treatment in the presence of water to obtain pretreated clay; (3) mixing the pretreated clay with a solution containing Mn... 2+ Solution I and hydrogen peroxide are subjected to a second heating treatment to obtain intermediate material; (4) The intermediate material is contacted and mixed with ammonia water to obtain modified clay. The modified clay prepared by the method provided by the present invention ensures the maximum exposure of Mn-O-Mn active sites, so as to ensure the efficient capture of macromolecular color-developing substances, and has good application prospects in the field of oil color removal.

Description

Technical Field

[0001] This invention relates to the field of oil decolorization and refining technology, specifically to modified clay and its preparation method, and methods for removing color from oil products. Background Technology

[0002] Raw materials such as ethylene cracking tar, coal tar pitch and waste mineral oil contain polycyclic aromatic hydrocarbons, colloids and metalloporphyrins and other color-developing substances, which generally have a dark color (GBT / 3143>500), which seriously limits their subsequent hydrogenation, clay refining or food-grade solvent reuse.

[0003] Traditional single activated clay adsorbents have poor selectivity for polycyclic aromatic hydrocarbons with three or more rings, require large quantities, and generate a large amount of waste soil; single solvent extraction tends to extract useful aromatic hydrocarbons along with the adsorbent, resulting in a decrease in yield and high energy consumption for solvent recovery.

[0004] Currently, industrial methods for oil decolorization can be categorized into four types: hydrogenation saturation decolorization, oxidative decolorization, adsorption decolorization, and extraction decolorization. However, hydrogenation decolorization requires high temperature and pressure, resulting in large investments; oxidative decolorization easily generates new quinones and azo dyes, which actually increase the color intensity; and neither adsorption nor extraction alone can achieve both "deep decolorization" and "high yield".

[0005] Therefore, developing a modified clay with significant advantages for use in the field of oil decolorization is of great importance. Summary of the Invention

[0006] The purpose of this invention is to overcome the problem that existing technologies have poor effects in removing color from oil products using clay adsorbents.

[0007] To achieve the above objectives, a first aspect of the present invention provides a method for preparing modified clay, the method comprising: (1) Under an inert atmosphere, the white clay is preheated to obtain activated white clay; (2) In the presence of water, the activated clay and the acidic solution are subjected to a first heating treatment and a drying treatment in sequence to obtain pretreated clay; (3) The pretreated white clay containing Mn 2+ Solution I and hydrogen peroxide are subjected to a second heating treatment to obtain intermediate material; Mn in solution I 2+ The concentration is 0.2-0.5 mol / L; with Mn 2+ The molar ratio of the solution I (calculated as H2O2) to the hydrogen peroxide is 1:0.5-4. (4) The intermediate material and ammonia water are mixed to obtain modified clay.

[0008] A second aspect of the present invention provides modified clay prepared by the method described in the first aspect above.

[0009] A third aspect of the present invention provides a method for removing color from oil, the method comprising: S1. The modified clay and the dark-colored oil with a color of 500-600 platinum cobalt color number are mixed in the first contact to obtain the first decolorized oil; S2. The first-stage decolorized oil and the extractant are subjected to countercurrent extraction to obtain refined oil; The modified clay is the modified clay described in the second aspect above.

[0010] Compared with the prior art, the present invention has at least the following advantages: (1) This invention utilizes a specific "low-temperature pyrolysis-acidification-Mn" process. 2+ The "in-situ oxidation deposition" composite modification process reconstructs the pore structure of bleaching clay and constructs a high-density Mn-O-Mn active center, allowing Mn elements to be uniformly loaded on the bleaching clay surface in the form of MnOOH. This invention can ensure maximum exposure of Mn-O-Mn active sites without adding surface modifiers, thus ensuring efficient capture of macromolecular chromogenic substances. This makes the resulting modified bleaching clay a promising candidate for oil color removal.

[0011] (2) Compared with hydrogenation processes that require high temperature and pressure and are prone to olefin saturation, and oxidation processes that are prone to side reactions that generate new chromogenic compounds (such as quinones and azo compounds), the method for removing color from oil products provided by this invention utilizes a coupled process of deep adsorption with modified clay and extraction with an extractant. This not only enables operation at normal pressure and low temperature, significantly reducing equipment investment and energy consumption, but more importantly, the selective retention of modified clay in the first step greatly reduces the load on subsequent extraction units, allowing the extractant to accurately extract residual polycyclic aromatic hydrocarbons (PCA). This staged decolorization strategy effectively solves the problems of "large dosage, large amount of waste soil, and insufficient decolorization depth" in traditional adsorption methods and "low yield and difficult solvent recovery" in single extraction methods. It is suitable for the industrial refining of ethylene cracking tar, coal tar pitch, and waste mineral oil, and has significant energy efficiency advantages and environmental friendliness.

[0012] (3) The method for removing color from oil products provided by this invention overcomes the shortcomings of existing hydrodecolorization methods, such as loss of unsaturated hydrocarbons and color rebound caused by oxidative decolorization. The main advantages of adsorption-extraction coupled decolorization are its simplicity, ability to deeply remove color-producing substances under mild conditions, strong selectivity for polycyclic aromatic hydrocarbons and metalloporphyrins in oil products, non-reaction with target hydrocarbons, and no product loss. Experimental data show that this method can reduce the color of ethylene cracking tar and coal tar pitch from 500 platinum cobalt color number to ≤165 platinum cobalt color number, and reduce the PCA content to below 6.0%, making it a very promising oil decolorization technology. Detailed Implementation

[0013] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0014] As previously stated, a first aspect of the present invention provides a method for preparing modified clay, the method comprising: (1) Under an inert atmosphere, the white clay is preheated to obtain activated white clay; (2) In the presence of water, the activated clay and the acidic solution are subjected to a first heating treatment and a drying treatment in sequence to obtain pretreated clay; (3) The pretreated white clay containing Mn 2+ Solution I and hydrogen peroxide are subjected to a second heating treatment to obtain intermediate material; Mn in solution I 2+ The concentration is 0.2-0.5 mol / L; with Mn 2+ The molar ratio of the solution I (calculated as H2O2) to the hydrogen peroxide is 1:0.5-4. (4) The intermediate material and ammonia water are mixed to obtain modified clay.

[0015] Preferably, in step (1), the average diameter of the clay particles is ≤0.5mm.

[0016] In order to remove excess acidic components, according to a preferred embodiment, the method further includes, in step (2), washing the material after the first heat treatment with water and monitoring the pH value of the washing water until it is neutral, and then drying the washed material to obtain pretreated white clay.

[0017] The present invention does not have special requirements for the drying conditions, as long as the washed material is completely dry. For example, the drying process is carried out in an oven for 2.5-3.5 hours.

[0018] According to another preferred embodiment, the method further includes: in step (2), grinding the dried material to obtain the pretreated white clay with an average particle diameter of 0.31-1.27 mm.

[0019] Preferably, in step (1), the preheating conditions include: a temperature of 140-160℃ and a holding time of 3-5h.

[0020] In a preferred embodiment, in step (1), the preheating treatment conditions further include a heating rate of 3-5℃ / min.

[0021] Preferably, in step (1), the inert atmosphere is introduced at a flow rate of 15-25 mL / min.

[0022] In a preferred embodiment, the inert atmosphere is nitrogen and / or argon.

[0023] Preferably, in step (1), the activated clay is first mixed with water to form a slurry, and then the slurry and the acidic solution are subjected to the first heating treatment in an aluminum pan.

[0024] In a preferred embodiment, in step (2), the conditions for the first heat treatment include: a temperature of 90-110°C and a time of 2-4 hours.

[0025] Preferably, in step (3), the conditions for the second heat treatment include: a temperature of 80-100°C and a time of 1-2 hours.

[0026] In a preferred embodiment, in step (4), the conditions for contact mixing include: a temperature of 20-30°C, a rotation speed of 150-200 rpm, and a time of 5-8 h.

[0027] Preferably, in step (2), the H in the acidic solution + The concentration is 2-5 mol / L.

[0028] In a preferred embodiment, in step (2), the amount of acidic solution used is 25-30 mL relative to 100 g of the activated clay.

[0029] Preferably, in step (3), the concentration of hydrogen peroxide is 9.0-10.5 mol / L.

[0030] In a preferred embodiment, in step (3), the amount of solution I used is 250-300 mL relative to 100 g of the pretreated clay.

[0031] In a preferred embodiment, in step (3), the volume of hydrogen peroxide used is 10-15 mL relative to 100 g of the pretreated clay.

[0032] Preferably, in step (4), the concentration of the ammonia water is 8.0-13.5 mol / L.

[0033] In a preferred embodiment, in step (4), the amount of ammonia water used is 150-180 mL relative to 100 g of the pretreated clay.

[0034] Preferably, in step (1), the clay is selected from at least one of bentonite, diatomite and kaolin.

[0035] In a preferred embodiment, in step (2), the acidic solution is selected from at least one of nitric acid solution, sulfuric acid solution, and hydrochloric acid solution; Preferably, in step (3), the solution I is selected from at least one of manganese nitrate solution, manganese sulfate solution, and manganese chloride solution.

[0036] In a preferred embodiment, the method further includes: in step (4), the materials that are in contact and mixed are subjected to a first drying, a hot water washing, and a second drying in sequence to obtain the modified clay.

[0037] Preferably, the conditions for the first drying include: a temperature of 90-110°C and a time of 1.5-2 hours.

[0038] The present invention does not impose any particular restrictions on the conditions of the hot water washing; it is only necessary to remove unbound impurities. For example, washing with hot water at 70-80°C for 6-10 times is permitted.

[0039] The present invention does not have any special requirements for the second drying conditions, as long as the material washed with hot water is completely dried. Those skilled in the art can make selections based on known technical means in the art, and the present invention will not elaborate further here.

[0040] It should be noted that the present invention does not have any particular requirements for the type of water, and those skilled in the art can select it according to known techniques in the field. For example, distilled water is used for the water washing.

[0041] As previously stated, a second aspect of the present invention provides modified clay prepared by the method described in the first aspect.

[0042] In a preferred embodiment, the modified clay has an average particle diameter of 20–80 mesh (Chinese standard sieve). As previously described, a third aspect of the present invention provides a method for removing color from oil, the method comprising: S1. The modified clay and the dark-colored oil with a color of 500-600 platinum cobalt color number are mixed in the first contact to obtain the first decolorized oil; S2. The first-stage decolorized oil and the extractant are subjected to countercurrent extraction to obtain refined oil; The modified clay is the modified clay described in the second aspect above.

[0043] In a preferred embodiment, in step S1, the mass ratio of the modified clay to the dark-colored oil is 1:1.5-2.5. The inventors of this invention have discovered that, under this preferred embodiment, costs can be saved while ensuring excellent color removal.

[0044] According to a preferred embodiment, in step S2, the extractant is sulfolane and dimethyl sulfoxide in a mass ratio of (3-7):(7-3). The inventors of this invention have found that this preferred embodiment results in better oil removal.

[0045] Preferably, in step S2, the volume ratio of the primary decolorizing oil to the extractant is 1:1.5-2.5.

[0046] In a preferred embodiment, in step S1, the conditions for the first contact mixing include: a temperature of 50-70°C and a time of 0.5-2 hours.

[0047] Preferably, in step S2, the conditions for countercurrent extraction include: a temperature of 60-80°C and a time of 20-40 min.

[0048] In a preferred embodiment, the method further includes: in step S2, after the material after countercurrent extraction is allowed to stand and separate into layers, the raffinate phase is subjected to vacuum distillation to recover the extracted and aromatic oil products.

[0049] Preferably, the refined oil has a color intensity of ≤165 (platinum cobalt), more preferably ≤75 (platinum cobalt), and even more preferably ≤60 (platinum cobalt).

[0050] The present invention will be described in detail below through examples. Unless otherwise specified, the instruments, reagents, and materials involved in the following examples are all conventional instruments, reagents, and materials, which can be obtained through legitimate commercial channels. Unless otherwise stated, all reagents used are commercially available analytical grade products.

[0051] White clay: Purchased from the 184th Regiment of the 10th Agricultural Division. The sample was first ground to make the average particle diameter 0.5mm. Then, it was made into a slurry in distilled water. Impurities such as sand and gravel at the bottom of the slurry were removed by decantation. Finally, it was placed in an oven at 110℃ to dry for later use.

[0052] Acidic solution: hydrochloric acid solution, H + The concentration is 5 mol / L.

[0053] Solution I: Manganese sulfate solution, containing Mn 2+ The concentration is 0.5 mol / L.

[0054] Solution II: Manganese sulfate solution, containing Mn 2+ The concentration is 0.1 mol / L.

[0055] Solution DI: Copper sulfate solution, in which Cu 2+ The concentration is 0.5 mol / L.

[0056] Hydrogen peroxide: concentration 9.8 mol / L.

[0057] Ammonia solution: concentration 13.4 mol / L.

[0058] Dark-colored oil: Ethylene cracked tar, with a color of approximately 500 platinum cobalt color number, and a PCA (polycyclic aromatic hydrocarbon) content of 10.9%.

[0059] Extractant: Extractant I: sulfolane and dimethyl sulfoxide in a mass ratio of 7:3.

[0060] Extractant II: Sulfolane and dimethyl sulfoxide in a mass ratio of 2:8.

[0061] Preparation Example 1 This preparation example illustrates the preparation of modified clay according to the formulations in Table 1 and the following steps: (1) Under an inert atmosphere (nitrogen, flow rate of 20 mL / min), the white clay was preheated (heating rate of 4 °C / min, temperature of 150 °C, time of 4 h) to obtain activated white clay; (2) First, the activated clay is mixed with 1000mL of water to form a slurry. Then, the slurry and acid solution are subjected to a first heating treatment in an aluminum pan (temperature is 100℃, time is 3h). The material after the first heating treatment is washed with water, and the pH value of the washing water is monitored until it is neutral (pH value is about 7). The washed material is then subjected to drying treatment (drying in an oven for 3h) and grinding treatment in sequence to obtain the pretreated clay. (3) The pretreated white clay containing Mn 2+Solution I and hydrogen peroxide were subjected to a second heating treatment (temperature 95℃, time 1h) to obtain intermediate material; (4) The intermediate material and ammonia water are contacted and mixed (temperature is 25℃, speed is 165rpm, time is 6h), and the contact-mixed material is subjected to first drying (temperature is 100℃, time is 2h), hot water washing (75℃ hot water washing 8 times), and second drying in sequence to obtain modified white clay, named modified white clay-1.

[0062] Table 1

[0063] Preparation Example 2 The preparation examples were carried out using a similar method to Preparation Example 1, except that the formulations are shown in Table 1. For the parts not listed, the same as in Preparation Example 1 was used to obtain modified clay, which was named Modified Clay-2.

[0064] Preparation Example 3 The preparation example was carried out using a method similar to that of Preparation Example 1, except that in step (2), H in the acidic solution was... + The concentration was adjusted to 1 mol / L; For the parts not listed, the same as in Preparation Example 1 was used to obtain modified clay, which was named Modified Clay-3.

[0065] Comparative Preparation Example 1 This comparative preparation example was prepared using a method similar to that of Preparation Example 1, except that: Step (1) is omitted, and in step (2), the activated clay in preparation example 1 is replaced with white clay; For any parts not listed, the same preparation method as in Example 1 was used to obtain modified clay, which was named Modified Clay-D1.

[0066] Comparative Preparation Example 2 This comparative preparation example was prepared using a method similar to that of Preparation Example 1, except that: In step (3), solution I in preparation example 1 is replaced with an equal volume of solution II; For any parts not listed, the same preparation method as in Example 1 was used to obtain modified clay, which was named Modified Clay-D2.

[0067] Comparative preparation example 3 This comparative preparation example was prepared using a method similar to that of Preparation Example 1, except that: In step (3), the volume of hydrogen peroxide used is controlled so that Mn 2+ The molar ratio of the solution I (calculated as H2O2) to the hydrogen peroxide is 1:0.4. For the parts not listed, the same as in Preparation Example 1 was used to obtain modified clay, which was named Modified Clay-D3.

[0068] Comparative preparation example 4 This comparative preparation example was prepared using a method similar to that of Preparation Example 1, except that: In step (4), ammonia water is replaced with an equal volume of sodium hydroxide solution with a concentration of 1 mol / L; For any parts not listed, the same preparation method as in Example 1 was used to obtain modified clay, which was named Modified Clay-D4.

[0069] Comparative preparation example 5 This comparative preparation example was prepared using a method similar to that of Preparation Example 1, except that: In step (3), solution I in preparation example 1 is replaced with an equal volume of solution DI; For any parts not listed, the same preparation method as in Example 1 was used to obtain modified clay, which was named Modified Clay-D5.

[0070] Example 1 This embodiment illustrates the process of removing oil color using the formula in Table 2 and following the steps outlined below: S1. The modified clay and dark oil are mixed in the first contact (temperature 60℃, time 1.5h) to obtain a first-stage decolorized oil; S2. The first decolorized oil and the extractant are subjected to countercurrent extraction (temperature 70℃, time 30min) to obtain refined oil; after the material after countercurrent extraction is allowed to stand and separate into layers, the raffinate phase is subjected to vacuum distillation to recover the extract and aromatic oil.

[0071] Table 2

[0072] Unless otherwise specified, Examples 2-4 were carried out using a method similar to that of Example 1, except that the formulations are as shown in Table 2, and any parts not listed are the same as in Example 1.

[0073] Comparative Example 1 This comparative example was carried out using a method similar to that of Example 1, except that in step S1, the modified clay was replaced with an equal mass of modified clay-D1. All parts not listed are the same as in Example 1.

[0074] Comparative Example 2 This comparative example was carried out using a method similar to that of Example 1, except that in step S1, the modified clay was replaced with an equal mass of modified clay-D2. All parts not listed are the same as in Example 1.

[0075] Comparative Example 3 This comparative example was carried out using a method similar to that of Example 1, except that in step S1, the modified clay was replaced with an equal mass of modified clay-D3. All parts not listed are the same as in Example 1.

[0076] Comparative Example 4 This comparative example was carried out using a method similar to that of Example 1, except that in step S1, the modified clay was replaced with an equal mass of modified clay-D4. All parts not listed are the same as in Example 1.

[0077] Comparative Example 5 This comparative example was carried out using a method similar to that of Example 1, except that in step S1, the modified clay was replaced with an equal mass of modified clay-D5. All parts not listed are the same as in Example 1.

[0078] Test case The color of the refined oils obtained in the above examples was tested using the method in GB / T 3143 standard, and the results are shown in Table 3: Wherein, the color removal rate = (color of dark oil - color of refined oil) / color of dark oil × 100%.

[0079] Table 3

[0080] The results above show that the modified clay prepared by the method provided by this invention is very suitable for removing the color of dark oil products. The method for removing the color of oil products provided by this invention can reduce the color of ethylene cracking tar and coal tar pitch from 500 platinum cobalt color number to ≤165 platinum cobalt color number and reduce the PCA content to below 6.0%, which is a very promising oil decolorization technology.

[0081] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing modified kaolin, characterized in that, The method includes: (1) The white clay was preheated under an inert atmosphere to obtain activated white clay; (2) In the presence of water, the activated clay and the acidic solution are subjected to a first heating treatment and a drying treatment in sequence to obtain pretreated clay; (3) The pretreated white clay containing Mn 2+ Solution I and hydrogen peroxide are subjected to a second heating treatment to obtain intermediate material; Mn in solution I 2+ The concentration is 0.2-0.5 mol / L; with Mn 2+ The molar ratio of the solution I (calculated as H2O2) to the hydrogen peroxide is 1:0.5-4. (4) The intermediate material and ammonia water are mixed to obtain modified clay.

2. The method according to claim 1, characterized in that, The method further includes: in step (2), grinding the dried material to obtain the pretreated white clay with an average particle diameter of 0.31-1.27 mm.

3. The method according to claim 1, characterized in that, In step (1), the preheating conditions include: a temperature of 140-160℃ and a holding time of 3-5h; And / or, in step (2), the conditions for the first heat treatment include: a temperature of 90-110°C and a time of 2-4 hours; And / or, in step (3), the conditions for the second heat treatment include: a temperature of 80-100°C and a time of 1-2 hours; And / or, in step (4), the conditions for contact mixing include: a temperature of 20-30°C, a rotation speed of 150-200 rpm, and a time of 5-8 h.

4. The method according to any one of claims 1-3, characterized in that, In step (2), the acidic solution contains H + The concentration is 2-5 mol / L; And / or, in step (2), the amount of acidic solution used is 25-30 mL relative to 100 g of the activated clay.

5. The method according to any one of claims 1-3, characterized in that, In step (3), the concentration of the hydrogen peroxide is 9.0-10.5 mol / L; And / or, in step (3), the amount of solution I used is 250-300 mL relative to 100 g of the pretreated clay.

6. The method according to any one of claims 1-3, characterized in that, In step (4), the concentration of the ammonia water is 8.0-13.5 mol / L; And / or, the amount of ammonia water used is 150-180 mL relative to 100 g of the pretreated clay.

7. The method according to any one of claims 1-3, characterized in that, In step (1), the white clay is selected from at least one of bentonite, diatomite and kaolin; And / or, in step (2), the acidic solution is selected from at least one of nitric acid solution, sulfuric acid solution, and hydrochloric acid solution; And / or, in step (3), the solution I is selected from at least one of manganese nitrate solution, manganese sulfate solution, and manganese chloride solution.

8. Modified clay prepared by the method according to any one of claims 1-7.

9. A method for removing color from oil products, characterized in that, The method includes: S1. The modified clay and the dark-colored oil with a color of 500-600 platinum cobalt color number are mixed in the first contact to obtain the first decolorized oil; S2. The primary decolorized oil and the extractant are subjected to countercurrent extraction to obtain refined oil; The modified clay is the modified clay according to claim 8.

10. The method according to claim 9, characterized in that, In step S1, the mass ratio of the modified clay to the dark oil is 1:1.5-2.5; And / or, in step S2, the extractant is sulfolane and dimethyl sulfoxide in a mass ratio of (3-7):(7-3); And / or, in step S2, the volume ratio of the primary decolorizing oil to the extractant is 1:1.5-2.5; And / or, in step S1, the conditions for the first contact mixing include: a temperature of 50-70°C and a time of 0.5-2h; And / or, in step S2, the conditions for countercurrent extraction include: a temperature of 60-80°C and a time of 20-40 min.

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