A method for regenerating a working solution for producing hydrogen peroxide by the anthraquinone process

Abstract

The present invention provides a method for regenerating a working solution used in the production of hydrogen peroxide by the anthraquinone process, belonging to the technical field of hydrogen peroxide synthesis. The regeneration method is as follows: the working solution is introduced into a regeneration bed and contacted with an internal regenerant for a period of time for regeneration, and then the working solution is output to obtain the regenerated working solution. The preparation method of the regenerant includes preparing modified alumina, compounding, and surface modification. The method of surface modification is as follows: the CaOMnO2 / modified alumina composite is added to deionized water, stirred for 5-7 h, then tetraethyl orthosilicate is added, ultrasonically dispersed, and reacted for 20-30 h. Then, centrifugation is carried out. After the precipitate is washed clean, it is added to an ethylenediaminetetraacetic acid solution, and then 3-aminopropyltriethoxysilane is added, and stirred and reacted for 3-4 h. After filtration and drying, the regenerant is obtained. The regenerant of the present invention has good regeneration effect, the regeneration increment is 16.12-21.45 g / L, and the service life reaches 99-108 days.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen peroxide synthesis, and particularly relates to a method for regenerating a working solution for producing hydrogen peroxide by the anthraquinone method. Background Art

[0002] Hydrogen peroxide, namely an aqueous hydrogen peroxide solution, is a colorless, transparent liquid with a slight pungent odor, having strong oxidizing property, bleaching property, weak reducing property, and weak acidity. Due to its unique chemical properties, hydrogen peroxide has wide applications in many fields such as medical disinfection, dyeing and weaving bleaching, oxygen preparation, food treatment, water treatment, etc.

[0003] Currently, the synthesis methods of hydrogen peroxide mainly include electrolytic water method, alcohol oxidation method, catalase method, anthraquinone method, etc. Among them, the anthraquinone method is the most main method for industrial production of hydrogen peroxide at present, accounting for about 95% of the global output. The principle of this method is that after dissolving anthraquinone in an appropriate solvent to form a working solution, under the joint action of a catalyst, hydrogen, and oxygen, anthraquinone is cyclically hydrogenated and oxidized, and at the same time, hydrogen peroxide is generated. Then, through steps such as extraction and post-treatment, hydrogen peroxide products are obtained. However, during the cyclic hydrogenation and oxidation of anthraquinone, anthraquinone will undergo side reactions to generate a series of degradation products. The accumulation of degradation products will affect the quality of hydrogen peroxide products and the stable operation of production devices. Using a suitable catalyst can regenerate the degradation products and convert them back into effective anthraquinone, reduce the content of degradation products in the working solution, and reduce the impact on production caused by the accumulation of degradation products.

[0004] Currently, activated alumina is used industrially to regenerate degradation products. However, 1. The mechanical strength of activated alumina is insufficient and its stability is poor, so that it is easy to powder in an alkaline working solution, increasing the burden of alkali separation in the post-treatment process; 2. The crystallization precipitation of some degradation products and solvent components in the working solution on the surface of activated alumina will block the pores, resulting in a decrease in the effective surface area of activated alumina and a decrease in catalytic activity.

[0005] Patent CN105174229A discloses a composite anthraquinone method hydrogen peroxide working solution activity regenerant and its preparation method, which adopts a composite layered structure composed of activated alumina in the outer layer and calcium oxide in the inner layer. This method improves the activity of the regenerant, and the total degradation products in the working solution after regeneration can be controlled below 20 g / L. However, the mechanical strength of activated alumina and the problem of blockage of pores on the surface of activated alumina by crystallization precipitation have not been effectively improved. Summary of the Invention

[0006] Aiming at the problems existing in the prior art, the present invention provides a method for regenerating a working solution for producing hydrogen peroxide by the anthraquinone method, and realizes the following invention purposes: providing a regenerant with high stability of the internal activated alumina, not easily blocked by crystallization in the pores, and a long service life, thereby improving the regeneration effect on the working solution.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for regenerating the working fluid used in the production of hydrogen peroxide by the anthraquinone method, comprising the following steps:

[0009] Pass the working fluid into the regeneration bed, contact it with the internal regenerant, control the regeneration temperature at 50 - 60 °C, and the contact time between the working fluid and the regenerant at 40 - 60 min. Then output the working fluid to obtain the regenerated working fluid;

[0010] The preparation method of the regenerant includes preparing modified alumina, compounding, and surface modification;

[0011] The method for preparing the modified alumina is as follows: Add aluminum isopropoxide and isopropanol to deionized water, stir and hydrolyze at 65 - 75 °C for 3.8 - 4.2 h, then raise the temperature to 110 - 130 °C, add phosphoric acid, and react for 1.5 - 2.5 h to obtain alumina sol. Slowly drip the alumina sol into the double-layer solution of paraffin oil and ammonia water to form alumina microspheres. After 2.7 - 3.3 h, filter out the alumina microspheres, dry them at 105 - 115 °C for 7 - 9 h, then transfer them to a muffle furnace, heat them at a rate of 2 - 4 °C / min to 550 - 650 °C, and calcine for 3 - 4 h to obtain the modified alumina;

[0012] The mass ratio of the deionized water, aluminum isopropoxide, isopropanol, and phosphoric acid is 5 - 7:16.5 - 17.5:6 - 8:2.8 - 3.2;

[0013] The stirring rate is 500 - 700 r / min;

[0014] The alumina sol is slowly dripped, controlling the dripping particle size at 1.5 - 2.5 mm and the frequency at 15 - 25 drops / min;

[0015] For the double-layer solution, the lower layer is ammonia water with a layer height of 4 - 6 cm and a mass fraction of 12 - 18%, and the upper layer is paraffin oil with a layer height of 18 - 22 cm.

[0016] The compounding method is as follows: Grind the modified alumina, pass it through a 170 - 230 mesh sieve, then add it to the mixed solution of calcium nitrate and manganese nitrate, impregnate for 4 - 6 h, then evaporate to remove the excess water. The obtained solid is dried at 100 - 120 °C for 2.5 - 3.5 h, and then calcined at 450 - 550 °C for 3.6 - 4.4 h to obtain the CaOMnO2 / modified alumina composite;

[0017] The mass ratio of the modified alumina, calcium nitrate, and manganese nitrate is 85 - 95:6 - 8:2 - 4;

[0018] In the mixed solution of calcium nitrate and manganese nitrate, the mass fraction of calcium nitrate is 13-17%, and the mass fraction of manganese nitrate is 8-10%.

[0019] The method of surface modification is as follows: Add the CaOMnO2 / modified alumina composite into deionized water, stir magnetically for 5-7 h, then add tetraethyl orthosilicate, disperse ultrasonically for 0.8-1.2 h, react at room temperature for 20-30 h, then centrifuge for 8-12 min. After washing the precipitate with deionized water and ethanol until clean, add it into an ethylenediaminetetraacetic acid solution, then add 3-aminopropyltriethoxysilane, stir and react at 70-90 °C for 3-4 h, filter, and dry the filter cake at 50-70 °C to constant weight to obtain the regenerant;

[0020] The mass ratio of the CaOMnO2 / modified alumina composite, deionized water, and tetraethyl orthosilicate is 0.8-1.2:38-42:8-10;

[0021] The mass ratio of the CaOMnO2 / modified alumina composite, ethylenediaminetetraacetic acid, and 3-aminopropyltriethoxysilane is 12-18:3-5:0.8-1.2;

[0022] The rate of magnetic stirring is 350-450 r / min, the centrifugation rate is 2500-3500 r / min, and the rate of stirring reaction is 40-60 r / min;

[0023] The mass fraction of the ethylenediaminetetraacetic acid solution is 20-30%.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] For conventional activated alumina, during the calcination process, dehydration condensation occurs between adjacent hydroxyl groups inside to form Al-O-Al. However, for the modified alumina of the present invention, after being modified with phosphoric acid, during the calcination process, dehydration condensation occurs between adjacent hydroxyl groups inside to form Al-O-P-O-Al, increasing the bond length between adjacent Als 3+ and reducing the interfacial stress, thereby improving the stability of the modified alumina and making the modified alumina not easily pulverized;

[0026] A layer of silica is coated on the surface of the modified alumina, further improving the stability of the modified alumina. At the same time, the surface of the silica is modified. Specifically, ethylenediaminetetraacetic acid is connected to the silica using the silane coupling agent 3-aminopropyltriethoxysilane. Ethylenediaminetetraacetic acid can complex metal impurities in the working fluid to prevent the pulverized modified alumina from entering the next process;

[0027] Crystallization of some degradation products and solvent components in the working fluid will be blocked by the silica on the surface and then fixed on the surface of the regenerant by ethylenediaminetetraacetic acid, without entering the internal modified alumina pores. When the surface precipitation accumulates, it can be removed by simply heating and dissolving regularly, which improves the service life of the regenerant. Detailed implementation method

[0028] Example 1

[0029] Pass the working fluid into the regeneration bed to contact with the internal regenerant, control the regeneration temperature at 55 °C, and the contact time between the working fluid and the regenerant at 50 min. Then output the working fluid to obtain the regenerated working fluid.

[0030] The initial effective anthraquinone content of the working fluid is 118.37 g / L, and the total degradation product content is 50.44 g / L. After regeneration, the effective anthraquinone content of the working fluid is 139.82 g / L, the regeneration increment is 21.45 g / L, the total degradation product content is 28.17 g / L, and the service life of the regenerant reaches 108 days.

[0031] The preparation method of the regenerant includes preparing modified alumina, compounding, and surface modification.

[0032] The method for preparing modified alumina is as follows: Add aluminum isopropoxide and isopropanol to deionized water, stir and hydrolyze at 70 °C for 4 h, then raise the temperature to 120 °C, add phosphoric acid, and react for 2 h to obtain alumina sol. Slowly drip the alumina sol into the double-layer solution of paraffin oil and ammonia water to form alumina microspheres. After 3 h, filter out the alumina microspheres, dry them at 110 °C for 8 h, then transfer them to a muffle furnace, heat up to 600 °C at a rate of 3 °C / min, and calcine for 3.5 h to obtain modified alumina.

[0033] The mass ratio of deionized water, aluminum isopropoxide, isopropanol, and phosphoric acid is 6∶17∶7∶3.

[0034] The stirring rate is 600 r / min.

[0035] The alumina sol is slowly dripped, controlling the dripping particle size at 2 mm and the frequency at 20 drops / min.

[0036] For the double-layer solution, the lower layer is ammonia water with a layer height of 5 cm and a mass fraction of 15%, and the upper layer is paraffin oil with a layer height of 20 cm.

[0037] The compounding method is as follows: Grind the modified alumina, pass it through a 200-mesh sieve, then add it to the mixed solution of calcium nitrate and manganese nitrate, impregnate for 5 h, then evaporate to remove the excess water, dry the obtained solid at 110 °C for 3 h, and then calcine at 500 °C for 4 h to obtain the CaOMnO2 / modified alumina composite.

[0038] The mass ratio of the modified alumina, calcium nitrate, and manganese nitrate is 90∶7∶3;

[0039] In the mixed solution of calcium nitrate and manganese nitrate, the mass fraction of calcium nitrate is 15%, and the mass fraction of manganese nitrate is 9%.

[0040] The method of surface modification is as follows: Add the CaOMnO2 / modified alumina composite into deionized water, stir magnetically for 6 h, then add tetraethyl orthosilicate, disperse ultrasonically for 1 h, react at room temperature for 24 h, then centrifuge for 10 min. After washing the precipitate with deionized water and ethanol until clean, add it into an ethylenediaminetetraacetic acid solution, then add 3-aminopropyltriethoxysilane, stir and react at 80 °C for 3.5 h, filter, and dry the filter cake at 60 °C to constant weight to obtain the regenerant;

[0041] The mass ratio of the CaOMnO2 / modified alumina composite, deionized water, and tetraethyl orthosilicate is 1∶40∶9;

[0042] The mass ratio of the CaOMnO2 / modified alumina composite, ethylenediaminetetraacetic acid, and 3-aminopropyltriethoxysilane is 15∶4∶1;

[0043] The rate of magnetic stirring is 400 r / min, the centrifugation rate is 3000 r / min, and the rate of stirring reaction is 50 r / min;

[0044] The mass fraction of the ethylenediaminetetraacetic acid solution is 25%.

[0045] Example 2

[0046] Pass the working fluid into the regeneration bed, contact it with the internal regenerant, control the regeneration temperature at 50 °C, and the contact time between the working fluid and the regenerant at 40 min. Then output the working fluid to obtain the regenerated working fluid;

[0047] The initial effective anthraquinone content of the working fluid is 118.37 g / L, the total degradation product content is 50.44 g / L. The effective anthraquinone content of the regenerated working fluid is 137.66 g / L, the regeneration increment is 19.29 g / L, the total degradation product content is 30.53 g / L, and the service life of the regenerant reaches 103 days;

[0048] The preparation method of the regenerant includes preparing modified alumina, compounding, and surface modification;

[0049] The method for preparing the modified alumina is as follows: Add aluminum isopropoxide and isopropanol to deionized water, stir and hydrolyze at 65 °C for 3.8 h, then raise the temperature to 110 °C, add phosphoric acid, and react for 1.5 h to obtain an alumina sol. Slowly drip the alumina sol into a double-layer solution of paraffin oil and ammonia water to form alumina microspheres. After 2.7 h, filter out the alumina microspheres, dry them at 105 °C for 7 h, then transfer them to a muffle furnace, heat them to 550 °C at a rate of 2 °C / min, and calcine for 3 h to obtain the modified alumina;

[0050] The mass ratio of the deionized water, aluminum isopropoxide, isopropanol, and phosphoric acid is 5∶16.5∶6∶2.8;

[0051] The stirring rate is 500 r / min;

[0052] The alumina sol is slowly dripped, and the dropping particle size is controlled to be 1.5 mm, and the frequency is 15 drops / min;

[0053] For the double-layer solution, the lower layer is ammonia water with a layer height of 4 cm and a mass fraction of 12%, and the upper layer is paraffin oil with a layer height of 18 cm.

[0054] The method for compounding is as follows: Grind the modified alumina, pass it through a 170-mesh sieve, then add it to a mixed solution of calcium nitrate and manganese nitrate, impregnate for 4 h, then evaporate to remove the excess water, dry the obtained solid at 100 °C for 2.5 h, and then calcine at 450 °C for 3.6 h to obtain the CaOMnO2 / modified alumina composite;

[0055] The mass ratio of the modified alumina, calcium nitrate, and manganese nitrate is 85∶6∶2;

[0056] In the mixed solution of calcium nitrate and manganese nitrate, the mass fraction of calcium nitrate is 13% and the mass fraction of manganese nitrate is 8%.

[0057] The method for surface modification is as follows: Add the CaOMnO2 / modified alumina composite to deionized water, magnetically stir for 5 h, then add tetraethyl orthosilicate, ultrasonically disperse for 0.8 h, react at room temperature for 20 h, then centrifuge for 8 min. After washing the precipitate with deionized water and ethanol, add it to an ethylenediaminetetraacetic acid solution, then add 3-aminopropyltriethoxysilane, stir and react at 70 °C for 3 h, filter, and dry the filter cake at 50 °C to constant weight to obtain the regenerant;

[0058] The mass ratio of the CaOMnO2 / modified alumina composite, deionized water, and tetraethyl orthosilicate is 0.8∶38∶8;

[0059] The mass ratio of the CaOMnO2 / modified alumina composite, ethylenediaminetetraacetic acid, and 3-aminopropyltriethoxysilane is 12∶3∶0.8;

[0060] The rate of magnetic stirring is 350 r / min, the centrifugation rate is 2500 r / min, and the rate of stirring reaction is 40 r / min;

[0061] The mass fraction of the ethylenediaminetetraacetic acid solution is 20%.

[0062] Example 3

[0063] The working fluid is introduced into the regeneration bed and contacts with the internal regenerant. The regeneration temperature is controlled at 60 °C, and the contact time between the working fluid and the regenerant is 60 min. Then the working fluid is output to obtain the regenerated working fluid;

[0064] The initial effective anthraquinone content of the working fluid is 118.37 g / L, the total degradation product content is 50.44 g / L. The effective anthraquinone content of the regenerated working fluid is 134.49 g / L, the regeneration increment is 16.12 g / L, the total degradation product content is 36.25 g / L, and the service life of the regenerant reaches 99 days;

[0065] The preparation method of the regenerant includes preparing modified alumina, compounding, and surface modification;

[0066] The method for preparing modified alumina is as follows: Add aluminum isopropoxide and isopropanol to deionized water, stir and hydrolyze at 75 °C for 4.2 h, then raise the temperature to 130 °C, add phosphoric acid, and react for 2.5 h to obtain alumina sol. Slowly drip the alumina sol into the double-layer solution of paraffin oil and ammonia water. After 3.3 h of forming alumina microspheres, filter out the alumina microspheres, dry them at 115 °C for 9 h, then transfer them to a muffle furnace, heat them at a rate of 4 °C / min to 650 °C, and calcine for 4 h to obtain modified alumina;

[0067] The mass ratio of the deionized water, aluminum isopropoxide, isopropanol, and phosphoric acid is 7∶17.5∶8∶3.2;

[0068] The stirring rate is 700 r / min;

[0069] The alumina sol is slowly dripped, and the controlled dropping particle size is 2.5 mm, and the frequency is 25 drops / min;

[0070] For the double-layer solution, the lower layer is ammonia water with a layer height of 6 cm and a mass fraction of 18%, and the upper layer is paraffin oil with a layer height of 22 cm.

[0071] The compounding method is as follows: Grind the modified alumina, pass it through a 230-mesh sieve, then add it to the mixed solution of calcium nitrate and manganese nitrate, impregnate for 6 h, then evaporate to remove the excess water, dry the obtained solid at 120 °C for 3.5 h, and then calcine at 550 °C for 4.4 h to obtain the CaOMnO2 / modified alumina composite;

[0072] The mass ratio of the modified alumina, calcium nitrate, and manganese nitrate is 95∶8∶4;

[0073] In the mixed solution of calcium nitrate and manganese nitrate, the mass fraction of calcium nitrate is 17% and the mass fraction of manganese nitrate is 10%.

[0074] The surface modification method is as follows: Add the CaOMnO2 / modified alumina composite into deionized water, stir magnetically for 7 h, then add tetraethyl orthosilicate, disperse ultrasonically for 1.2 h, react at room temperature for 30 h, then centrifuge for 12 min. After washing the precipitate with deionized water and ethanol until clean, add it into an ethylenediaminetetraacetic acid solution, then add 3-aminopropyltriethoxysilane, stir and react at 90 °C for 4 h, filter, and dry the filter cake at 70 °C to constant weight to obtain the regenerant;

[0075] The mass ratio of the CaOMnO2 / modified alumina composite, deionized water, and tetraethyl orthosilicate is 1.2∶42∶10;

[0076] The mass ratio of the CaOMnO2 / modified alumina composite, ethylenediaminetetraacetic acid, and 3-aminopropyltriethoxysilane is 18∶5∶1.2;

[0077] The rate of magnetic stirring is 450 r / min, the centrifugation rate is 3500 r / min, and the rate of stirring reaction is 60 r / min;

[0078] The mass fraction of the ethylenediaminetetraacetic acid solution is 30%.

[0079] Example 4

[0080] Pass the working fluid into the regeneration bed to contact with the internal regenerant, control the regeneration temperature at 55 °C, and the contact time between the working fluid and the regenerant is 50 min, then output the working fluid to obtain the regenerated working fluid;

[0081] The initial effective anthraquinone content of the working fluid is 118.37 g / L, the total degradation product content is 50.44 g / L. The effective anthraquinone content of the regenerated working fluid is 136.51 g / L, the regeneration increment is 18.14 g / L, the total degradation product content is 30.59 g / L, and the service life of the regenerant reaches 87 days;

[0082] The preparation method of the regenerant includes compounding and surface modification;

[0083] The compounding method is as follows: Grind activated alumina, sieve it through a 200-mesh sieve, then add it to a mixed solution of calcium nitrate and manganese nitrate. After impregnation for 5 h, evaporate the excess water. The obtained solid is dried at 110 °C for 3 h, and then calcined at 500 °C for 4 h to obtain the CaOMnO2 / activated alumina composite;

[0084] The mass ratio of the activated alumina, calcium nitrate, and manganese nitrate is 90∶7∶3;

[0085] In the mixed solution of calcium nitrate and manganese nitrate, the mass fraction of calcium nitrate is 15%, and the mass fraction of manganese nitrate is 9%.

[0086] The surface modification method is as follows: Add the CaOMnO2 / activated alumina composite to deionized water, stir magnetically for 6 h, then add tetraethyl orthosilicate, ultrasonically disperse for 1 h, react at room temperature for 24 h, then centrifuge for 10 min. After washing the precipitate with deionized water and ethanol, add it to an ethylenediaminetetraacetic acid solution, then add 3-aminopropyltriethoxysilane, stir and react at 80 °C for 3.5 h, filter, and dry the filter cake at 60 °C to constant weight to obtain the regenerant;

[0087] The mass ratio of the CaOMnO2 / activated alumina composite, deionized water, and tetraethyl orthosilicate is 1∶40∶9;

[0088] The mass ratio of the CaOMnO2 / activated alumina composite, ethylenediaminetetraacetic acid, and 3-aminopropyltriethoxysilane is 15∶4∶1;

[0089] The rate of magnetic stirring is 400 r / min, the centrifugation rate is 3000 r / min, and the rate of stirring reaction is 50 r / min;

[0090] The mass fraction of the ethylenediaminetetraacetic acid solution is 25%.

[0091] Example 5

[0092] Pass the working fluid into the regeneration bed to contact with the internal regenerant, control the regeneration temperature at 55 °C, and the contact time between the working fluid and the regenerant is 50 min. Then output the working fluid to obtain the regenerated working fluid;

[0093] The initial effective anthraquinone content of the working fluid is 118.37 g / L, the total degradation product content is 50.44 g / L. The effective anthraquinone content of the regenerated working fluid is 138.76 g / L, the regeneration increment is 20.39 g / L, the total degradation product content is 36.17 g / L, and the service life of the regenerant reaches 104 days;

[0094] The preparation method of the regenerant includes preparing modified alumina, compounding, and surface modification;

[0095] The method for preparing the modified alumina is as follows: Add aluminum isopropoxide and isopropanol to deionized water, stir and hydrolyze at 70 °C for 4 h, then raise the temperature to 120 °C, add phosphoric acid, and react for 2 h to obtain an alumina sol. Slowly drip the alumina sol into a double-layer solution of paraffin oil and ammonia water to form alumina microspheres. After 3 h, filter out the alumina microspheres, dry them at 110 °C for 8 h, then transfer them to a muffle furnace, heat them to 600 °C at a rate of 3 °C / min, and calcine for 3.5 h to obtain the modified alumina;

[0096] The mass ratio of the deionized water, aluminum isopropoxide, isopropanol, and phosphoric acid is 6:17:7:3;

[0097] The stirring rate is 600 r / min;

[0098] The alumina sol is slowly dripped, and the dropping particle size is controlled to be 2 mm, and the frequency is 20 drops / min;

[0099] For the double-layer solution, the lower layer is ammonia water with a layer height of 5 cm and a mass fraction of 15%, and the upper layer is paraffin oil with a layer height of 20 cm.

[0100] The method for compounding is as follows: Grind the modified alumina, pass it through a 200-mesh sieve, then add it to a mixed solution of calcium nitrate and manganese nitrate, impregnate for 5 h, then evaporate to remove the excess water, dry the obtained solid at 110 °C for 3 h, and then calcine at 500 °C for 4 h to obtain the CaOMnO2 / modified alumina composite;

[0101] The mass ratio of the modified alumina, calcium nitrate, and manganese nitrate is 90:7:3;

[0102] In the mixed solution of calcium nitrate and manganese nitrate, the mass fraction of calcium nitrate is 15%, and the mass fraction of manganese nitrate is 9%.

[0103] The method for surface modification is as follows: Add the CaOMnO2 / modified alumina composite to deionized water, magnetically stir for 6 h, then add tetraethyl orthosilicate, ultrasonically disperse for 1 h, react at room temperature for 24 h, then centrifuge for 10 min, wash the precipitate with deionized water and ethanol until clean, and dry to constant weight at 60 °C to obtain the regenerant;

[0104] The mass ratio of the CaOMnO2 / modified alumina composite, deionized water, and tetraethyl orthosilicate is 1:40:9;

[0105] The rate of magnetic stirring is 400 r / min, and the centrifugation rate is 3000 r / min.

[0106] Example 6

[0107] Pass the working fluid into the regeneration bed, contact it with the internal regenerant, control the regeneration temperature at 55 °C, and the contact time between the working fluid and the regenerant at 50 min. Then output the working fluid to obtain the regenerated working fluid.

[0108] The initial effective anthraquinone content of the working fluid is 118.37 g / L, and the total degradation product content is 50.44 g / L. The effective anthraquinone content of the regenerated working fluid is 126.15 g / L, with a regeneration increment of 7.78 g / L. The total degradation product content is 40.53 g / L, and the service life of the regenerant reaches 88 days.

[0109] The preparation method of the regenerant includes preparing modified alumina and compounding.

[0110] The method for preparing the modified alumina is as follows: Add aluminum isopropoxide and isopropanol to deionized water, stir and hydrolyze at 70 °C for 4 h, then raise the temperature to 120 °C, add phosphoric acid, and react for 2 h to obtain alumina sol. Slowly drip the alumina sol into the double-layer solution of paraffin oil and ammonia water to form alumina microspheres. After 3 h, filter out the alumina microspheres, dry them at 110 °C for 8 h, then transfer them to a muffle furnace, heat them to 600 °C at a rate of 3 °C / min, and calcine for 3.5 h to obtain the modified alumina.

[0111] The mass ratio of the deionized water, aluminum isopropoxide, isopropanol, and phosphoric acid is 6∶17∶7∶3.

[0112] The stirring rate is 600 r / min.

[0113] The alumina sol is slowly dripped, controlling the dripping particle size at 2 mm and the frequency at 20 drops / min.

[0114] For the double-layer solution, the lower layer is ammonia water with a layer height of 5 cm and a mass fraction of 15%, and the upper layer is paraffin oil with a layer height of 20 cm.

[0115] The compounding method is as follows: Grind the modified alumina, pass it through a 200-mesh sieve, then add it to the mixed solution of calcium nitrate and manganese nitrate, impregnate for 5 h, then evaporate to remove the excess water. The obtained solid is dried at 110 °C for 3 h, and then calcined at 500 °C for 4 h to obtain the CaOMnO2 / modified alumina composite, which is the regenerant.

[0116] The mass ratio of the modified alumina, calcium nitrate, and manganese nitrate is 90∶7∶3.

[0117] In the mixed solution of calcium nitrate and manganese nitrate, the mass fraction of calcium nitrate is 15% and the mass fraction of manganese nitrate is 9%.

[0118] In Examples 1 to 6, the test methods for the initial effective anthraquinone content, total degradation product content, effective anthraquinone content of the working fluid after regeneration, and total degradation product content were gas-liquid chromatography.

[0119] From Examples 1 to 6, it can be seen that in Example 4, conventional activated alumina was used, and its regeneration effect was not much different from that of Examples 1 to 3. However, the conventional activated alumina was prone to pulverization, so the service life of the regenerant was short.

[0120] The regeneration effect and service life of Example 5 were not much different from those of Examples 1 to 3. However, there was no complexing effect on the pulverized modified alumina, and a small amount of pulverized modified alumina particles were contained in the working fluid after regeneration, increasing the separation burden in the next process.

[0121] In Example 6, due to the lack of protection of silica on the surface of the regenerant and the fixation of crystals, the regenerant was easily blocked by crystals, resulting in poor regeneration effect of the working fluid and short service life of the regenerant.

Claims

1. A method for regenerating a working solution for producing hydrogen peroxide by anthraquinone method, characterized in that: The regeneration method is to pass the working fluid into the regeneration bed, contact with the internal regeneration agent for a period of time, and then output the working fluid to obtain the regenerated working fluid; The preparation method of the regeneration agent includes preparing modified alumina, compounding, and surface modification; The method for preparing modified alumina comprises adding aluminum isopropoxide and isopropanol to deionized water, hydrolyzing for 3.8 to 4.2 hours, then heating to 110 to 130° C., adding phosphoric acid, reacting for 1.5 to 2.5 hours to obtain an alumina sol, slowly dropping the alumina sol into a double-layer solution of paraffin oil and ammonia water to form alumina microspheres, and after 2.7 to 3.3 hours, filtering and removing the alumina microspheres, drying and transferring them to a muffle furnace, and calcining for 3 to 4 hours to obtain modified alumina; The composite method comprises grinding the modified alumina, passing it through a 170-230 mesh sieve, and then adding it to a mixed solution of calcium nitrate and manganese nitrate, immersing it for 4-6 hours, evaporating and removing excess water, and drying and calcining the obtained solid to obtain a CaOMnO2 / modified alumina composite; The surface modification method comprises the following steps: adding a CaOMnO2 / modified alumina composite to deionized water, stirring the composite by magnetic force for 5 to 7 hours, adding tetraethyl orthosilicate, performing ultrasonic dispersion for 0.8 to 1.2 hours, reacting the composite at room temperature for 20 to 30 hours, and then centrifuging the composite for 8 to 12 minutes. After the precipitate is cleaned with deionized water and ethanol, the precipitate is added to an ethylenediaminetetraacetic acid solution, and then 3-aminopropyltriethoxysilane is added. The composite is reacted by stirring at 70 to 90° C. for 3 to 4 hours, and then filtered and dried to obtain a regeneration agent. The mass ratio of deionized water, aluminum isopropoxide, isopropanol and phosphoric acid is 5-7:16.5-17.5:6-8:2.8-3.

2. The alumina sol is slowly added dropwise, the particle size of the added dropwise addition is controlled to be 1.5-2.5 mm, and the frequency is 15-25 drops / min.

2. The method for regenerating a working solution for producing hydrogen peroxide by anthraquinone process according to claim 1, characterized in that: The contact time of the regeneration agent is 40 to 60 minutes, and the contact regeneration temperature is 50 to 60°C.

3. The method for regenerating a working solution for producing hydrogen peroxide by anthraquinone process according to claim 1, characterized in that: In the method for preparing modified alumina, the double-layer solution has a lower layer of ammonia water with a layer height of 4 to 6 cm and a mass fraction of ammonia water of 12 to 18%, and an upper layer of paraffin oil with a layer height of 18 to 22 cm.

4. The method for regenerating a working solution for producing hydrogen peroxide by anthraquinone process according to claim 1, characterized in that: In the surface modification method, the mass ratio of the CaOMnO2 / modified alumina composite, deionized water, and tetraethyl orthosilicate is 0.8-1.2:38-42:8-10, the mass ratio of the CaOMnO2 / modified alumina composite, ethylenediaminetetraacetic acid, and 3-aminopropyltriethoxysilane is 12-18:3-5:0.8-1.2, the magnetic stirring rate is 350-450 r / min, the centrifugal rate is 2500-3500 r / min, the stirring reaction rate is 40-60 r / min, and the mass fraction of the ethylenediaminetetraacetic acid solution is 20-30%.

5. The method for regenerating a working solution for producing hydrogen peroxide by anthraquinone method according to claim 1, characterized in that: In the composite method, the mass ratio of the modified aluminum oxide, calcium nitrate and manganese nitrate is 85-95:6-8:2-4, and in the mixed solution of calcium nitrate and manganese nitrate, the mass fraction of calcium nitrate is 13-17%, and the mass fraction of manganese nitrate is 8-10%.

6. The method for regenerating a working solution for producing hydrogen peroxide by anthraquinone method according to claim 1, characterized in that: In the composite method, the calcination temperature is 450-550° C. and the calcination time is 3.6-4.4 hours.