High-efficiency working fluid regenerant, preparation method thereof and working fluid regeneration method

Abstract

The invention discloses a high-efficiency liquid working solution regenerant, a preparation method thereof and a working solution regeneration method, the regenerant comprises a mixed solvent, an inorganic base and an organic base, and the mixed solvent is a mixture of ethanol and C9 aromatic hydrocarbon. The high-efficiency liquid regenerant prepared by the invention is used for regenerating the working solution, and has the advantages that the working solution regeneration capacity is high, the regeneration method is simple, the regeneration cost is low, the regenerated regenerant can be removed, and other impurities are not introduced.

Description

Technical Field

[0001] The invention relates to a regenerating agent for working fluid in hydrogen peroxide production and a working fluid regeneration method, in particular to a high-efficiency liquid working fluid regenerating agent and a preparation method thereof and a working fluid regeneration method. Background Art

[0002] As an ideal green oxidant, hydrogen peroxide has a wide range of uses in the chemical, environmental protection, pharmaceutical, and electronic industries. At present, the industrial production of hydrogen peroxide mainly adopts the anthraquinone process. The anthraquinone process mainly utilizes the characteristics of alkyl anthraquinone derivatives that can be hydrogenated and reduced, and then re-oxidized and restored, while producing hydrogen peroxide. The process of continuous preparation of hydrogen peroxide is realized through four steps of hydrogenation, oxidation, extraction, and post-treatment. However, in actual production, the hydrogenation and oxidation processes are accompanied by various inevitable side reactions, generating a large number of side reaction products, collectively referred to as degradation products. The generation of such degradation products will not only increase the production cost, but also cause changes in the properties of the working fluid, thereby leading to a series of process problems.

[0003] At present, the treatment methods for working fluid degradation products in industrial production mainly include the following two methods: 1. Use potassium carbonate or sodium hydroxide and other aqueous solutions to clean and regenerate the working fluid. Since the main component of the working fluid is heavy aromatic hydrocarbons, it is difficult for the anthraquinone degradation products in the working fluid to contact with the alkaline solution, resulting in poor actual regeneration effect.

[0004] 2. After alkaline treatment with solid catalysts such as activated alumina, catalytic regeneration treatment is carried out in the form of a fixed bed. This is also the main regeneration method for working fluid in industrial production. The advantage of this regeneration method is that the regeneration effect is obvious and it is suitable for continuous production. The disadvantages are that the consumption of activated alumina is large, the amount of three wastes is large, and the pollution of the working fluid by alumina dust. Taking a generating device with a production capacity of 100,000 / ton (27.5%) as an example, its annual consumption of activated alumina is about 400-600 tons, and the consumption will increase further with the increase of operating time. Summary of the invention

[0005] The purpose of the present invention is to solve the above-mentioned problems existing in the prior art and provide a high-efficiency liquid working fluid regeneration agent and a preparation method thereof and a working fluid regeneration method. The high-efficiency liquid regeneration agent can be fully dissolved in the working fluid, thereby improving the contact effect between the regeneration agent and the working fluid; by utilizing the regeneration effect of inorganic alkali on degradation products and the strong alkalinity of organic alkali, the regeneration and removal of degradation products in the working fluid are achieved. The preparation method is simple, the cost is low, the regeneration and removal effect of the degradation products is obvious, and after regeneration, the alkalis and alcohols can be completely removed by water washing without introducing other impurities.

[0006] A first aspect of the present invention provides a high-efficiency liquid working fluid regeneration agent, the regeneration agent comprising: a mixed solvent, an inorganic base, and an organic base, wherein the mixed solvent is a mixture of ethanol and C9 aromatic hydrocarbons.

[0007] Preferably, the volume ratio of ethanol to C9 aromatics is 10:5-1, preferably 10:3-1, and more preferably 10:2.

[0008] Preferably, the inorganic base is sodium hydroxide, potassium hydroxide or a mixture of sodium hydroxide and potassium hydroxide. More preferably, it is sodium hydroxide. Preferably, the mass ratio of the inorganic base to the mixed solvent is 1:6-15, preferably 1:6-10, and more preferably 1:10.

[0009] Preferably, the organic base is sodium ethoxide, potassium ethoxide or a mixture of sodium ethoxide and potassium ethoxide, more preferably sodium ethoxide.

[0010] Preferably, the mass ratio of the organic base to the mixed solvent is 1:15 to 25, preferably 1:20 to 25, and more preferably 1:25.

[0011] A second aspect of the present invention provides a method for preparing a high-efficiency liquid working fluid regeneration agent, comprising the following steps: (1) preparing a mixed solvent with ethanol and C9 aromatic hydrocarbons; (2) adding an inorganic base to the mixed solvent prepared in step (1) and stirring to dissolve; (3) refluxing the solution obtained in step (2) to allow part of the inorganic base to react with ethanol to generate an organic base; (4) Slowly add the organic base to the liquid obtained in step (3) and stir to dissolve.

[0012] Preferably, in step (3), the reflux temperature is 75-80° C., and the reflux time is 30-40 min.

[0013] A third aspect of the present invention provides a working fluid regeneration method, comprising the following steps: (1) Adding the high-efficiency liquid regeneration agent into the working fluid; (2) Control the regeneration temperature and regeneration pressure to obtain the regenerated working fluid; (3) adding water to the working solution regenerated in step (2), stirring, standing and separating the lower aqueous phase and the upper working solution; (4) Repeat step (3) with the upper working solution obtained in step (3).

[0014] Preferably, in step (1), the volume ratio of the high-efficiency liquid regeneration agent to the working liquid is 1:20 to 100, preferably 1:20 to 50, and more preferably 1:25.

[0015] Preferably, in step (2), the regeneration temperature is 40-80° C., and the regeneration pressure is 0-100 kPa.

[0016] Preferably, in step (2), under stirring conditions, a certain regeneration temperature and regeneration pressure are controlled, and the reaction is stirred to obtain a regenerated working solution. The stirring reaction time is preferably 30 to 60 minutes.

[0017] Preferably, in step (2), the mixed solution obtained in step (1) is placed in a container, and the mixed solution is pumped into the bottom of the regeneration tube by a pump, and overflows from the top of the regeneration tube back to the container, and continuously circulates and regenerates to obtain a regenerated working solution. Preferably, a peristaltic pump is used to transport the mixed solution, and the regeneration tube is provided with a jacket.

[0018] Preferably, in step (3), the volume ratio of water to working fluid is 1:5 to 20, preferably 1:5 to 10, and more preferably 1:5; the stirring temperature is 30 to 50° C., and the stirring time is 15 to 30 min.

[0019] Preferably, in step (4), step (3) is repeated 1 to 2 times.

[0020] The invention provides a high-efficiency liquid working fluid regeneration agent and a preparation method thereof and a working fluid regeneration method. The high-efficiency liquid regeneration agent can be fully dissolved in the working fluid, thereby improving the contact effect between the regeneration agent and the working fluid. The regeneration effect of the inorganic base on the degradation products and the strong alkalinity of the organic base are utilized to achieve the regeneration and removal of the degradation products in the working fluid. The preparation method is simple, the cost is low, the regeneration and removal effect of the degradation products is obvious, and after the regeneration, the alkali and alcohol can be completely removed by water washing without introducing other impurities. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto.

[0022] The detection method of the effective anthraquinone content and the degradation product content in the working solution is to use high performance liquid chromatography for analysis and detection.

[0023] Example 1

[0024] Take 160 ml of anhydrous ethanol and 40 ml of trimethylol and mix them evenly, then add them to a 500 ml three-necked flask. Add 15 g of sodium hydroxide to the flask and start stirring. After the sodium hydroxide is completely dissolved, turn on the water bath heating and reflux at 80°C for 30 minutes. Stop heating and slowly add 6.4 g of sodium ethoxide to the flask. Continue stirring until the sodium ethoxide is completely dissolved to obtain regeneration agent 1. Take 2L working solution and 80ml regeneration agent 1 and mix them evenly, then add them to a 5L stainless steel reactor, start stirring and heating, and when the temperature rises to 50℃, add nitrogen to the reactor, control the regeneration pressure to 50Kpa, and stir the reaction for 60min. After the reaction is completed, add about 400ml pure water to the reactor, control the water washing temperature to 50℃, stir for 30min, let stand for 30min, and discharge the lower aqueous phase. Repeat the above water washing process; The effective anthraquinone content in the working solution before regeneration was determined to be 132.8 g / L, and the degradation product content was 30.8 g / L; after regeneration, the effective anthraquinone content in the working solution was 141.2 g / L, and the degradation product content was 24.5 g / L.

[0025] Example 2

[0026] The 40 ml of trimethylol in Example 1 is replaced with 25 ml of trimethylol + 15 ml of mesitylene, and the 15 g of sodium hydroxide and 6.4 g of sodium ethoxide are replaced with 10 g of sodium hydroxide + 5 g of potassium hydroxide and 5 g of sodium ethoxide + 1 g of potassium ethoxide. The rest is the same as in Example 1, and a regenerated agent 2 and a regenerated working solution can be obtained; The effective anthraquinone content in the working solution before regeneration was determined to be 132.8 g / L, and the degradation product content was 30.8 g / L; after regeneration, the effective anthraquinone content in the working solution was 143.7 g / L, and the degradation product content was 20.5 g / L.

[0027] Example 3

[0028] The 15g sodium hydroxide and 6.4g sodium ethoxide in Example 1 are replaced with 5g sodium hydroxide and 12.8g sodium ethoxide, and the rest is the same as in Example 1, to obtain a regeneration agent 3 and a regenerated working solution; The effective anthraquinone content of the working solution before regeneration was 132.8 g / L, and the content of degradation products was 30.8 g / L; after regeneration, the effective anthraquinone content in the working solution was 136.6 g / L, and the content of degradation products was 18.7 g / L. The reason for this may be that sodium ethoxide has a stronger nucleophilicity and can react with phenols and anthrones in the degradation products to achieve the removal of degradation products. However, its regeneration performance is not as good as that of sodium hydroxide.

[0029] Example 4

[0030] Take 2L working solution and 80ml regeneration agent 1, mix them evenly, add them into a 5L stainless steel reactor, start stirring and heating, wait until the temperature rises to 80℃, add nitrogen into the reactor, control the regeneration pressure to 100Kpa, and stir for 60min. After the reaction is completed, add about 400ml pure water into the reactor, control the water washing temperature to 50℃, stir for 30min, let stand for 30min, and discharge the lower aqueous phase. Repeat the above water washing process; The effective anthraquinone content in the working solution before regeneration was determined to be 132.8 g / L, and the degradation product content was 30.8 g / L; after regeneration, the effective anthraquinone content in the working solution was 144.6 g / L, and the degradation product content was 21.3 g / L.

[0031] Example 5

[0032] The 160 ml ethanol and 40 ml trimethylol in Example 1 are replaced with 180 ml ethanol and 20 ml trimethylol, and the 15 g sodium hydroxide and 6.4 g sodium ethoxide are replaced with 25 g sodium hydroxide and 12 g sodium ethoxide, and the rest is the same as Example 1, to obtain a regeneration agent 4 and a regenerated working solution; The effective anthraquinone content in the working solution before regeneration was determined to be 132.8 g / L, and the degradation product content was 30.8 g / L; after regeneration, the effective anthraquinone content in the working solution was 138.7 g / L, and the degradation product content was 17.4 g / L.

[0033] Example 6

[0034] Take 2L working solution and 80ml regeneration agent 1 and mix them evenly, then add them into a 5L three-necked flask. Use a peristaltic pump to control the working solution flow rate to 100ml / min, and continuously send the working solution in the three-necked flask to the bottom of the jacketed glass regeneration tube. Control the temperature of the regeneration tube jacket to 80℃. The working solution overflows from the top of the regeneration tube and returns to the three-necked flask. After continuous circulation and regeneration for 60min, stop the pump. Add about 400ml of pure water into the three-necked flask, control the water washing temperature to 50℃, stir for 30min, let stand for stratification for 30min, discharge the lower aqueous phase, repeat the above water washing process, and obtain the regenerated working solution. The effective anthraquinone content in the working solution before regeneration was determined to be 132.8 g / L, and the degradation product content was 30.8 g / L; after regeneration, the effective anthraquinone content in the working solution was 136.3 g / L, and the degradation product content was 25.4 g / L.

[0035] Comparative Example 1 Take 2L working solution and 200g sodium hydroxide aqueous solution (20%) and mix them evenly, then add them into a 5L stainless steel reactor, start stirring and heating, and stir and react for 60 minutes at normal pressure when the temperature rises to 50°C. After the reaction is completed, add about 400ml pure water into the reactor, control the water washing temperature to 50°C, stir for 30 minutes, let stand for 30 minutes, and discharge the lower aqueous phase. Repeat the above water washing process; The effective anthraquinone content in the working solution before regeneration was determined to be 132.8 g / L, and the degradation product content was 30.8 g / L; after regeneration, the effective anthraquinone content in the working solution was 135.3 g / L, and the degradation product content was 28.6 g / L.

[0036] Comparative Example 2 The reaction temperature in Comparative Example 1 was increased to 80°C, and the rest was the same as in Comparative Example 1; The effective anthraquinone content in the working solution before regeneration was determined to be 132.8 g / L, and the degradation product content was 30.8 g / L; after regeneration, the effective anthraquinone content in the working solution was 136.5 g / L, and the degradation product content was 27.7 g / L.

[0037] Comparative Example 3 Replacing 15 g of sodium hydroxide in Example 1 with 15 g of sodium ethoxide, and the rest is the same as in Example 1, to obtain a regeneration agent 4 and a regenerated working solution; The effective anthraquinone content in the working solution before regeneration was determined to be 132.8 g / L, and the degradation product content was 30.8 g / L; after regeneration, the effective anthraquinone content in the working solution was 134.1 g / L, and the degradation product content was 16.2 g / L.

Claims

1. A high-efficiency liquid working fluid regeneration agent, the regeneration agent comprising: A mixed solvent, an inorganic base, and an organic base, wherein the mixed solvent is a mixture of ethanol and C9 aromatic hydrocarbons.

2. The high-efficiency liquid working fluid regeneration agent according to claim 1, characterized in that: The volume ratio of ethanol to C9 aromatics is 10:5-1, preferably 10:3-1.

3. The high-efficiency liquid working fluid regeneration agent according to claim 1, characterized in that: The inorganic alkali is sodium hydroxide, potassium hydroxide or a mixture of sodium hydroxide and potassium hydroxide.

4. The high-efficiency liquid working fluid regeneration agent according to claim 1, characterized in that: The mass ratio of the inorganic base to the mixed solvent is 1:6-15, preferably 1:6-10.

5. The high-efficiency liquid working fluid regeneration agent according to claim 1, characterized in that: The organic base is sodium ethoxide, potassium ethoxide or a mixture of sodium ethoxide and potassium ethoxide, more preferably sodium ethoxide.

6. The high-efficiency liquid working fluid regeneration agent according to claim 1, characterized in that: The mass ratio of the organic base to the mixed solvent is 1:15-25, preferably 1:20-25.

7. A method for preparing a high-efficiency liquid working fluid regeneration agent according to any one of claims 1 to 6, comprising the following steps: (1) preparing a mixed solvent with ethanol and C9 aromatic hydrocarbons; (2) adding an inorganic base to the mixed solvent prepared in step (1) and stirring to dissolve; (3) refluxing the solution obtained in step (2) to allow part of the inorganic base to react with ethanol to generate an organic base; (4) Slowly add the organic base to the liquid obtained in step (3) and stir to dissolve.

8. A method for regenerating a working fluid, comprising the following steps: (1) Adding the high-efficiency liquid working fluid regeneration agent described in any one of claims 1 to 6 or the high-efficiency liquid regeneration agent prepared by the preparation method described in claim 7 into the working fluid; (2) Control the regeneration temperature and regeneration pressure to obtain the regenerated working fluid; (3) adding water to the working solution regenerated in step (2), stirring, standing and separating the lower aqueous phase and the upper working solution; (4) Repeat step (3) with the upper working solution obtained in step (3).

9. The working fluid regeneration method according to claim 8, characterized in that: In step (1), the volume ratio of the high-efficiency liquid regeneration agent to the working liquid is 1:20 to 100, preferably 1:20 to 50.

10. The working fluid regeneration method according to claim 8, characterized in that: In step (3), the volume ratio of water to working fluid is 1:5-20, preferably 1:5-10.