Process for converting working solution solvent in hydrogen peroxide production

Abstract

The application discloses a process method for conversion of working liquid solvent in hydrogen peroxide production and belongs to the technical field of hydrogen peroxide production. The process method realizes conversion between acetic ester system and tetrabutylammonium system of working liquid solvent by improving process parameters of hydrogenation, extraction and white clay bed regeneration among anthraquinone method hydrogen peroxide solvents. The application can be used by mutual conversion according to market raw material price change, maximally reduces raw material cost, meets diversified chemical production, meanwhile, the process method can reduce system acidity, reduce hydrogenation side reaction, reduce alumina consumption and reduce energy consumption in the running process.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrogen peroxide production, and particularly relates to a process method for conversion of working liquid solvent in hydrogen peroxide production. BACKGROUND

[0002] Industrial production methods of hydrogen peroxide mainly include electrolysis method, anthraquinone method, isopropyl alcohol method, cathode and anode reduction method and direct combination of hydrogen and oxygen, etc. The electrolysis method has high current efficiency, short process flow and high product quality, but is gradually eliminated due to high power consumption and high production cost, and is not suitable for large-scale industrial production. The oxygen anode reduction method uses water and air as raw materials, has the characteristics of low cost, less investment and less pollution, but the method has not been realized for industrial production. Therefore, the anthraquinone method is the most important method for producing hydrogen peroxide at home and abroad.

[0003] The working liquid system of the anthraquinone method includes a full-acid system, an old process flash evaporation system, an acetate ester system, a tetrabutyl urea system and the like. How to take advantage of the existing system and make up for its shortcomings to reduce cost and increase efficiency is a problem to be solved in the field. SUMMARY

[0004] The purpose of the application is to provide a process method for conversion of working liquid solvent in hydrogen peroxide production, which can be used by mutual conversion according to the market raw material price changes, so as to reduce the raw material cost as much as possible and meet the diversified chemical production. At the same time, the process method can reduce the system acidity, reduce the hydrogenation side reaction, reduce the consumption of aluminum oxide and reduce the energy consumption in the running process.

[0005] In order to achieve the above purpose, the technical scheme adopted by the application is as follows.

[0006] A process method for conversion of working liquid solvent in hydrogen peroxide production, by improving the process parameters of hydrogenation, extraction and white clay bed regeneration among the solvents of anthraquinone hydrogen peroxide, the conversion between the acetate ester system and the tetrabutyl urea system of the working liquid solvent is realized.

[0007] The process method comprises the following steps:

[0008] S1, hydrogenation reaction:

[0009] S11, when the working liquid system is the acetate ester system, the hydrogen flow is adjusted, so that the content of acetic acid in the hydrogenation reaction is reduced to less than 10 g / L, and the hydrogenation degree is less than 30%;

[0010] S12, tetrabutyl urea is supplemented into the hydrogenation reaction to a concentration of 15 g / L;

[0011] S13, hydrogen is introduced into the hydrogenation reaction system, and the hydrogen load is controlled according to the observation index;

[0012] S2, extraction process: control the rising flow rate of the working liquid in the extraction process, so that the hydrogen peroxide extraction residue index is less than or equal to 0.3g / L;

[0013] S3, regeneration process of the white clay bed: when the acidity of the working liquid is less than or equal to 2mg / L, the alkali tower is cut out of the system, and if the acidity of the working liquid is still less than 2mg / L, the B type alumina in the hydrogenated white clay bed is replaced by A type alumina in whole or in part.

[0014] Preferably, in step S11, when the working liquid system is an acetate system, the acetate content is 29g / L, and the hydrogenation degree is 40%.

[0015] Further preferably, the hydrogen flow is 2300m 3 / h; and the circulation amount is 700m 3 / h.

[0016] Preferably, in step S12, the supplement is continuous supplement, and the supplement rate is 3m3 / h.

[0017] Preferably, in step S13, the observation index is any one of the filter pressure difference of the hydrogenated liquid, the temperature difference of the hydrogenated liquid cooler, and the flow rate of the hydrogenated white clay bed.

[0018] Further preferably, the hydrogen load is increased from 2300m 3 / h to 2600m 3 / h at a rate of 100m 3 / h per 2 hours.

[0019] Preferably, in step S2, the control method of the rising flow rate includes reducing the extraction temperature and / or reducing the sieve plate aperture in the extraction process; further preferably, the sieve plate aperture in the extraction process is reduced.

[0020] The process method of the present application further comprises controlling the liquid level of the tetrabutyl ammonium bromide system.

[0021] Specifically, the control method of the liquid level is to install a liquid level meter between the working liquid level of 0.86-0.9, and the liquid level meter is connected with the original liquid level meter to realize the switching between the acetate system and the tetrabutyl ammonium bromide system.

[0022] The acetate system in the present application is a working liquid solvent of anthraquinone, trioctyl phosphate, acetate and aromatic hydrocarbon; the tetrabutyl ammonium bromide system is a working liquid solvent of anthraquinone, trioctyl phosphate, aromatic hydrocarbon and tetrabutyl ammonium bromide, and the conversion between the working liquid solvents of the acetate system and the tetrabutyl ammonium bromide system is the conversion between the acetate and the tetrabutyl ammonium bromide.

[0023] Compared with the prior art, the present application has the following beneficial effects:

[0024] This invention can be adapted to different raw material prices based on market fluctuations, minimizing raw material costs and accommodating diverse chemical production processes. Simultaneously, this process reduces system acidity, minimizes hydrogenation side reactions, reduces alumina consumption, and decreases energy consumption during operation. Attached Figure Description

[0025] Figure 1 The diagram shows a simplified process flow chart of the hydrogenation reaction provided by this invention. In the diagram, 1 represents pressure difference, 2 represents temperature difference, and 3 represents flow rate.

[0026] Figure 2 The diagram shows a simplified flow chart of the extraction reaction process provided by this invention. In the diagram, 4 represents the sieve plate and 5 represents the extraction temperature. Detailed Implementation

[0027] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way. The following description is merely an exemplary illustration of the scope of protection of the present invention, and those skilled in the art can make various changes and modifications to the invention based on the disclosed content, which should also fall within the scope of protection of the present invention.

[0028] The following section uses a 150,000-ton hydrogen peroxide production unit as an example to detail the process of converting the working fluid solvent acetate into tetrabutylurine.

[0029] The current working fluid system is an acetate system. The first step is to reduce the acetate content from 29 g / L to below 10 g / L. Simultaneously, the degree of hydrogenation is reduced from 40% to below 30% to prevent solvent loss and precipitation in the hydrogenated solution, which would disrupt the maintenance of the total anthraquinone content in the system. Therefore, the volume is reduced for adjustment. At this point, the hydrogen gas volume is 2300 m³. 3 / h; circulation volume 700m 3 / h.

[0030] According to the working fluid component ratio, tetrabutylurine was added to the system to a concentration of 15 g / L. This addition process was continuous. If a continuous decrease in the system hydrogenation tower pressure was observed, the hydrogen load was further increased from 2300 m³ / L. 3 / h is increased by 100m every two hours 3 / h is regularly increased to 2600m 3 / h, such as Figure 1 As shown, the pressure difference between the hydrogenated liquid filter and the filter after the hydrogenated liquid pump, the flow rate of the hydrogenated liquid filter (which can be characterized by the pressure gauges at the inlet and outlet on site), and the flow rate of the hydrogenated clay bed are observed. The purpose is to prevent the precipitation of anthraquinone due to insufficient solvent volume after the hydrogen load increases, which would clog the filter.

[0031] Because the solute and solvent of the working liquid change greatly, the hydrogenated liquid cooler, hydrogenated liquid pump after-cooler full-welded plate exchanger is blocked due to the hydrogen anthraquinone precipitation, the heat exchange effect is poor, the hydrogenated tower temperature is over-temperature, the heat exchange temperature difference of the hydrogenated liquid cooler is observed, the hydrogen gas load is controlled, and there is no definite sequence between the increase of the filter pressure difference and the decrease of the hydrogenated white clay bed flow, which is only a parameter for observing the system reaction degree.

[0032] Because the density of the acetate ester system working liquid is higher than that of the tetrabutyl urea, after changing to the tetrabutyl urea system, the extraction tower extraction separation effect is stronger than that of the original one, and the working liquid rising flow rate is faster than that of the original one, the purpose of extraction is to extract hydrogen peroxide in the working liquid with water, if the working liquid rising flow rate is too fast, it will lead to incomplete extraction, the raffinate content is high, the hydrogen peroxide raffinate index is ≦0.3 g / L, and exceeding this index will directly affect the production safety of the hydrogenated tower to reach a flash explosion value.

[0033] The method for controlling the flow rate includes: 1. reducing the raffinate tower temperature to increase the viscosity of the working liquid and reduce the flow rate; and 2. changing the sieve plate hole number of the extraction tower to reduce the sieve plate hole diameter to achieve the flow rate. Figure 2 The present application changes 20 layers of upper tower of the extraction tower of the 150,000 tons hydrogen peroxide device, replaces 2 m 3 (15 pieces of sieve plates) in each layer with irregular stainless steel touch nets to increase the resistance.

[0034] After the working liquid system is changed to the tetrabutyl urea system, the working liquid density becomes smaller, and the densities of the hydrogenated liquid storage tank, the oxidized liquid storage tank, the circulating working liquid storage tank, the hydrogenated gas-liquid separator, the upper and lower tower gas-liquid separators of the oxidation tower and the magnetic flip plate liquid level meter are all 0.9-1.0, which is not consistent with the working liquid density of the tetrabutyl urea system. The present application installs a new magnetic flip plate liquid level meter between the working liquid 0.86-0.9. The new liquid level meter can be connected with the previous magnetic flip plate liquid level meter by using a three-way valve, to achieve the switching function of the acetate ester system and the tetrabutyl urea system.

[0035] In the original acetate ester system, when the system load hydrogen is 2800 m 3 / h, the system working liquid acidity is observed to be 2-5 mg / L, because the acetate ester system will hydrolyze into acidic substances, leading to the slow increase of the working liquid system acidity. After the tetrabutyl urea system is used, the system acidity will only increase during the hydrogenation and oxidation reactions, when the working liquid acidity is ≦2 mg / L, the alkali tower is cut out of the system to ensure the acid-base balance, and the premise of the system acid-base balance is to continuously supplement phosphoric acid into the system to control the oxidation acidity, the extraction acidity and the alkali tower cut-out system, the working liquid alkalinity decreases, the consumption of phosphoric acid is also reduced, to achieve the best point of material balance, which has a great effect on reducing the consumption of caustic soda and phosphoric acid.

[0036] If the base tower is cut off, if the working fluid acidity is still lower than 2mg / L, the B type alumina in the hydrogenated clay bed is all changed into A type alumina, the sodium content is reduced, the working fluid acidity at the outlet of the clay bed is improved, and the use amount of phosphoric acid is avoided from excessive consumption.

[0037] Because the regeneration of the clay bed is closely related to the use period of the alumina, the frequency of the replaced A type alumina will be increased, and the hydrogen gas load is taken as the standard.

[0038] The raw material consumption comparison of the acetate system and tetrabutyl urea is shown in Table 1.

[0039] Table 1

[0040]

[0041] The above description of the embodiments is for facilitating the ordinary skilled person in the art to understand and use the invention. The person skilled in the art can obviously easily make various modifications to these embodiments, and apply the general principles described herein to other embodiments without having to go through creative labor. Therefore, the invention is not limited to the above embodiments, and the improvements and modifications made by the person skilled in the art according to the disclosure of the invention without departing from the scope of the invention should be within the protection scope of the invention.

Claims

1. A process for solvent conversion of the working solution in hydrogen peroxide production, characterized in that, Includes the following steps: S1, hydrogenation reaction: S11. When the working fluid system is an acetate system, adjust the hydrogen flow rate to reduce the acetic acid content in the hydrogenation reaction to less than 10 g / L and the degree of hydrogenation to less than 30%. S12. Add tetrabutylurea to the hydrogenation reaction until the concentration is 15 g / L; S13. Introduce hydrogen into the hydrogenation reaction system and control the hydrogen load based on observed indicators; S2. Extraction process: Control the upward flow rate of the working liquid during the extraction process to ensure that the hydrogen peroxide raffinate residue index is ≤0.3g / L; S3. Regeneration process of the clay bed: When the acidity of the working solution is ≤2mg / L, the alkali tower is removed from the system. If the acidity of the working solution is still below 2mg / L, all or part of the type B alumina in the hydrogenated clay bed is replaced with type A alumina.

2. The process method according to claim 1, characterized in that, When the working solution system in step S11 is an acetate system, the acetic acid content is 29 g / L and the degree of hydrogenation is 40%.

3. The process method according to claim 1, characterized in that, The hydrogen flow rate is 2300 m³ / h; the circulation rate is 700 m³ / h.

4. The process method according to claim 1, characterized in that, The replenishment in step S12 is a continuous replenishment, with a replenishment rate of 3m. 3 / h.

5. The process method according to claim 1, characterized in that, The observation index mentioned in step S13 is any one of the following: pressure difference of the hydrogenated liquid filter, temperature difference of the hydrogenated liquid cooler, and flow rate of the hydrogenated clay bed.

6. The process method according to claim 1, characterized in that, The hydrogen load is: 100 m³ every 2 hours. 3 The rate was increased from 2300 m³ / h to 2600 m³ / h.

7. The process method according to claim 1, characterized in that, The method for controlling the upward flow rate in step S2 includes reducing the extraction temperature and / or reducing the aperture of the sieve plate during the extraction process.

8. The process method according to any one of claims 1-7, characterized in that, This includes controlling the liquid level in the tetrabutylurine system.

9. The process method according to claim 8, characterized in that, The liquid level control method is as follows: a liquid level gauge is installed between the working liquid level of 0.86 and 0.9, and the liquid level gauge is connected to the original liquid level gauge to realize the switching between the acetate system and the tetrabutylurine system.

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