Method and system for generating hydrogen peroxide

Abstract

A method and system for producing hydrogen peroxide are disclosed. The method includes the following steps: 1) hydrogenating a working solution containing alkylanthraquinone in the presence of hydrogenation catalyst particles and hydrogen, separating the working solution to obtain a circulating slurry and a hydrogenated solution, and recycling the circulating slurry; 2) dividing the hydrogenated solution into two streams and regenerating the first stream of the hydrogenated solution to obtain a regenerated hydrogenated solution; 3) contacting the second stream of the hydrogenated solution and the regenerated hydrogenated solution with an oxygen-containing gas to oxygenate the hydrogenated solution to obtain an oxidized solution; and 4) performing extraction and separation on the oxidized solution to obtain an extract containing hydrogen peroxide and a raffinate, and recycling the raffinate. The method substantially eliminates the temperature difference in the reactor bed, effectively improving hydrogenation selectivity, equipment efficiency, and hydrogenation efficiency, and extending the life of the hydrogenation catalyst.

Description

[Technical Field]

[0001] (Cross-reference to related applications) This application claims priority to a patent application filed on 14 October 2020, application number 202011095895.3, with the title of the invention being a method and system for generating hydrogen peroxide, the entire contents of which are included herein. (Technical field) This application relates to the domain of generating hydrogen peroxide, and more specifically, to a method and system for generating hydrogen peroxide. [Background technology]

[0002] Hydrogen peroxide, also known as hydrogen peroxide solution, is a green chemical product that produces little pollution during its production and use, and is therefore called a "clean" chemical product. It can be used as an oxidizing agent, bleaching agent, disinfectant, deoxidizing agent, polymerization initiator, and crosslinking agent, and is widely used in industries such as chemical industry, papermaking, environmental protection, electronics, food, pharmaceuticals, textiles, mining, and agricultural waste treatment.

[0003] The anthraquinone process is the mainstream method for industrially producing hydrogen peroxide, accounting for over 99% of global hydrogen peroxide production. Typically, existing anthraquinone processes include steps such as hydrogenation, oxidation, extraction, and post-treatment of the working solution. Here, the working solution containing alkylanthraquinone and hydrogen undergo a hydrogenation reaction in a hydrogenation reactor containing a catalyst, producing the corresponding hydrogenated anthraquinone, and the resulting solution is called the hydrogenated solution. In the oxygenation reactor, the hydrogenated solution undergoes an oxidation reaction in an oxygen-containing atmosphere (e.g., air), converting the hydrogenated anthraquinone back to the original alkylanthraquinone and simultaneously producing hydrogen peroxide, and the resulting solution is called the oxidized solution. Taking advantage of the difference in solubility of hydrogen peroxide in water and in the working solution, and the difference in density between the working solution and water, hydrogen peroxide in the oxidized solution is extracted with pure water, and the working solution obtained after extraction with water (also called raffinate) is reused after post-treatment. A post-treatment process commonly used in China involves decomposing H2O2 by drying and dehydrating it with a K2CO3 solution, separating the alkali by precipitation, and then regenerating the decomposition products by adsorbing them using activated alumina in a clay bed.

[0004] The hydrogen peroxide production technology used in China employs a fixed-bed hydrogenation process, which has the advantages of being easy to operate and not requiring catalytic separation, but it also has many drawbacks.

[0005] (1) Due to the large temperature rise (8-10°C) and local hot spots in the reaction bed layer, the hydrogenation efficiency is limited (6-8 g / L), resulting in low system efficiency. Compared to a similar-scale system with high hydrogenation efficiency, the working solution circulation is higher and the pump power consumption is higher.

[0006] (2) Catalysts are easily deactivated and must be regenerated or replaced regularly, which not only consumes steam but also causes the loss of precious metals from the working solution and catalyst. In fixed-bed hydrogenation processes currently used in China, catalysts need to be regenerated with steam every 3 to 6 months.

[0007] (3) The working solution is easily decomposed, and industrially, large amounts of activated alumina are used to continuously regenerate the circulating working solution, requiring frequent replacement of the activated alumina. As a result, large amounts of solid hazardous waste are generated, and the working solution is lost. For example, 5 kg of activated alumina is consumed and 3 kg of working solution is lost to produce 1 ton of hydrogen peroxide product.

[0008] (4) The equipment has poor safety and requires the use of a potassium carbonate drying tower to remove saturated water from the circulating working solution and enhance the regeneration of the working solution. Hydrogen peroxide is decomposed by alkali, which poses a potentially serious safety risk. Safety accidents occur every year in hydrogen peroxide equipment, and 80% of these accidents are due to alkali leakage into the oxidation and extraction units.

[0009] By adopting a slurry bed hydrogenation process, the production efficiency of the apparatus can be significantly improved, the amount of catalyst and circulating working solution used can be reduced, production costs can be lowered, hydrogenation efficiency can be improved (>10 g / L), and the reduction in catalyst activity can be offset by the continuous introduction and extraction of the catalyst. On the other hand, the slurry bed process enables a uniform hydrogenation reaction of anthraquinones and avoids the decomposition of the working solution caused by the formation of local hot spots during the reaction process.

[0010] Chinese Patent CN1233451C discloses a continuously operating slurry bed process reactor, the reactor having one or more layers of heat exchange tube members for heating / cooling the bed layer and one or more layers of liquid-solid separator members that can be automatically cleaned. However, the reactor has a complex structure and requires a large number of support members to be placed inside the reactor, the flow pattern inside the reactor is similar to a plugged flow, and despite the presence of multiple layers of heat exchange members, a temperature difference still exists in the bed layer. Because the liquid-solid separator members are located inside the reactor, overhauling is not easy, and when the liquid-solid separator members need to be disassembled and cleaned, the entire apparatus must be stopped, resulting in poor flexibility.

[0011] Chinese patent CN1108984C discloses a method for regenerating a working solution, in which at least a portion of the working solution is brought into contact with a catalyst mainly composed of γ-alumina at 40-150°C to regenerate byproducts in the working solution. When the working solution is regenerated in an "unreduced" state, i.e., before hydrogenation, the γ-alumina catalyst inevitably generates a considerable amount of fine powder, which can block the filter if it enters the slurry bed reactor. When the working solution is brought into contact with the γ-alumina catalyst at 40-150°C, not only are hydrogenation byproducts regenerated, but secondary side reactions also occur, and the resulting byproducts can enter the slurry bed reactor and potentially affect the activity of the hydrogenation catalyst.

[0012] Chinese patent CN204237558U discloses a post-treatment device for a hydrogen peroxide production process using the anthraquinone method, including an alkali tower and a vacuum dryer. Chinese patent application CN1334235A discloses a post-treatment technique for hydrogen peroxide production using the anthraquinone method, employing quantitative alkali injection to neutralize the acidity of the working solution returned to hydrogenation in order to ensure the alkalinity required by hydrogenation and to decompose a portion of the hydrogen peroxide in the working solution. Subsequently, moisture is removed by vacuum drying. Both of these post-treatment techniques require the introduction of alkaline liquid into the system, which is unsafe and poses serious potential safety risks.

[0013] Therefore, safe, stable, and efficient methods and systems for producing hydrogen peroxide are still needed in this field. [Overview of the project]

[0014] The object of the present application is to substantially eliminate the temperature difference in the reactor bed, effectively enhance the hydrogenation selectivity, device efficiency, and hydrogenation efficiency, and / or extend the lifespan of the hydrogenation catalyst, etc., so as to overcome one or more drawbacks of the above-mentioned prior art. On the other hand, the system can also eliminate the serious potential safety risks caused by alkali leakage, simplify the device, and effectively improve the safety of the system.

[0015] To achieve the above object, in one aspect, the present application provides a method for generating hydrogen peroxide, including the following steps.

[0016] 1) Supplying an operating solution containing alkyl anthraquinone to a hydrogenation reactor, hydrogenating alkyl anthraquinone under conditions where hydrogenation catalyst particles and hydrogen are present to obtain a slurry containing hydrogenated anthraquinone, by-products, and hydrogenation catalyst particles, recovering the hydrogenation catalyst particles from the slurry to obtain a circulating slurry rich in hydrogenation catalyst particles and a hydrogenation solution substantially free of hydrogenation catalyst particles, and returning the circulating slurry to the hydrogenation reactor; 2) Dividing the hydrogenation solution into two streams, regenerating the first stream of the hydrogenation solution to convert at least a part of the by-products contained in the first stream of the hydrogenation solution into alkyl anthraquinone to obtain a regenerated hydrogenation solution; 3) Contacting the second stream of the hydrogenation solution and the regenerated hydrogenation solution with an oxygen-containing gas for an oxidation reaction to obtain an oxidation solution containing hydrogen peroxide and alkyl anthraquinone; and 4) Extracting and separating the oxidation solution to obtain an extract containing hydrogen peroxide and a raffinate containing alkyl anthraquinone, and returning the raffinate to the hydrogenation reactor for use as a part of the operating solution; Here, the ratio of the volume flow rate of the circulating slurry to the volume flow rate of the operating solution is 6 to 20:1; The ratio of the mass flow rate of the first stream of the hydrogenation solution to the mass flow rate of the second stream of the hydrogenation solution is 10 to 50:50 to 90.

[0017] Preferably, step 1) further includes the steps of performing a first cooling on the circulating slurry to obtain a first cooling solution, and returning the first cooling solution to the hydrogenation reactor. More preferably, the temperature of the first cooling solution is 40 to 70°C.

[0018] In another embodiment, the present application provides a system for generating hydrogen peroxide, comprising a hydrogenation unit, a regeneration unit, an oxidation unit, and a separation unit; The hydrogenation unit is configured to hydrogenate a working solution containing alkylanthraquinone under conditions where hydrogenation catalyst particles and hydrogen are present, to obtain a slurry containing hydrogenated anthraquinone, by-products and hydrogenation catalyst particles, to recover the hydrogenation catalyst particles from the obtained slurry to obtain a circulating slurry rich in hydrogenation catalyst particles and a hydrogenation solution substantially free of hydrogenation catalyst particles, and to recirculate the circulating slurry; The regeneration unit is arranged to regenerate a portion of the hydrogenation solution, convert at least a portion of the by-products contained therein into alkylanthraquinones, and obtain a regenerated hydrogenation solution; The oxidation unit is arranged to bring the remaining portion of the hydrogenation solution and the regenerated hydrogenation solution into contact with an oxygen-containing gas to cause an oxidation reaction, thereby obtaining an oxidation solution containing hydrogen peroxide and alkylanthraquinone, and The separation unit is configured to extract and separate the oxidizing solution to obtain an extract containing hydrogen peroxide and a raffinate containing alkylanthraquinone, and to return the raffinate to the hydrogenation unit.

[0019] Compared to prior art, the method and system of this application have the following advantages.

[0020] 1) In this application, the circulating slurry is returned to the working solution at a specific mass flow rate ratio and mixed, and in particular, the circulating slurry after the first cooling is returned to the slurry bed reactor, so that the state inside the reactor is close to a completely mixed flow, the temperature difference in the reactor bed layer is substantially eliminated, and hydrogenation selectivity, apparatus efficiency and hydrogenation efficiency are improved, and in particular the hydrogenation efficiency can reach 10-18 g / L; 2) In the method of this application, the hydrogenation reaction of alkylanthraquinone is carried out first, and then a portion of the hydrogenation solution is regenerated. This prevents dust from the regenerated catalyst from entering the slurry bed reactor and prevents blockage of the filter, prevents a decrease in the activity of the hydrogenation catalyst due to secondary byproducts, extends the life of the hydrogenation catalyst, and reduces the costs and losses associated with the regeneration of the deactivation catalyst; 3) In this application, the desired regeneration effect of the working solution can be obtained by passing the hydrogenation solution at a mass flow rate of 10-50% through the regeneration reactor. Therefore, while operating the apparatus with high hydrogenation efficiency, the amount of regeneration catalyst in the working solution at a mass flow rate of 40-80% can be reduced, the generation of waste solids can be significantly reduced, and the economic efficiency and environmental protection of the apparatus can be significantly improved; 4) The method and system of this application can completely eliminate the use of alkali towers, can provide an entirely acidic environment within the apparatus, can eliminate serious potential safety risks caused by alkali leakage within the system while ensuring the stability of the hydrogenation reaction of the slurry bed, and can greatly improve the intrinsic safety of the hydrogen peroxide generator, in particular by vacuum drying at least a portion of the raffinate to obtain a residual liquid, water and / or organic matter for effective and environmentally friendly use.

[0021] Other features and advantages of this application will be described in detail in the following detailed description.

[0022] The drawings, which form part of this specification, are provided to aid in understanding this application and should not be considered limiting. This application can be interpreted by referring to the drawings in conjunction with the following detailed description. The drawings are as follows: [Brief explanation of the drawing]

[0023] [Figure 1] This is a schematic diagram of a preferred embodiment of the method and system for generating hydrogen peroxide according to the present application. [Figure 2] This is a schematic diagram of a more preferred embodiment of the method and system for generating hydrogen peroxide according to the present application. [Modes for carrying out the invention]

[0024] The embodiments for carrying out the invention will be described in detail below with reference to the drawings. The embodiments for carrying out the invention described herein are for the purpose of describing and interpreting this application only and do not limit this application.

[0025] All specific numerical values ​​(including the endpoints of numerical ranges) described in this text should be interpreted not as being limited to their exact values, but as further encompassing all values ​​close to those exact values, for example, all values ​​within ±5% of those exact values. Furthermore, with respect to the numerical ranges presented, one or more new numerical ranges can be obtained by making any combination between the endpoints of the range, between each endpoint and any specific value within the range, and between each specific value itself, and these new numerical ranges should also be deemed to be specifically described in this application.

[0026] Unless otherwise specified, terms used herein have the same meaning as those generally understood by those skilled in the art. If a term is defined herein and that definition differs from the common understanding in the art, the definition herein shall prevail.

[0027] In this application, unless otherwise specified, the "hydrogenation efficiency" refers to the weight of hydrogen peroxide obtained after oxidation of the hydrogenation solution relative to the volume of the working solution, expressed in units of g / L. That is, in the oxidation process, assuming the conversion rate and yield of hydrogenated anthraquinone contained in the hydrogenation solution are 100%, it is the amount (g) of hydrogen peroxide obtained from 1 L of working solution at the end of the oxidation process.

[0028] In this application, unless otherwise specified, all pressure values ​​presented are gauge pressures.

[0029] In this application, anything or any matter not explicitly described herein that is not mentioned can be directly applied without modification as is known in the art. Furthermore, any of the embodiments described herein may be freely combined with one or more embodiments described herein, and any technical solution or idea thus obtained shall be considered part of the original disclosure or description of this application and shall not be considered novel matter not disclosed or anticipated herein unless such combination is clearly unreasonable to a person skilled in the art.

[0030] All patents and non-patent literature referenced in the text, including but not limited to textbooks and academic papers, are incorporated in their entirety by reference.

[0031] As described above, in the first embodiment, the present application provides a method for producing hydrogen peroxide, comprising the following steps.

[0032] 1) A working solution containing alkylanthraquinone is supplied to a hydrogenation reactor, and the alkylanthraquinone is hydrogenated under conditions where hydrogenation catalyst particles and hydrogen are present to obtain a slurry containing hydrogenated anthraquinone, by-products and hydrogenation catalyst particles, the hydrogenation catalyst particles are recovered from the slurry to obtain a circulating slurry rich in hydrogenation catalyst particles and a hydrogenation solution substantially free of hydrogenation catalyst particles, and the circulating slurry is returned to the hydrogenation reactor; 2) Dividing the hydrogenation solution into two streams, regenerating the first stream of hydrogenation solution to convert at least a portion of the by-products contained in the first stream of hydrogenation solution into alkylanthraquinone, thereby obtaining a regenerated hydrogenation solution; 3) A step of bringing the hydrogenated solution and the regenerated hydrogenated solution from the second flow into contact with an oxygen-containing gas to cause an oxidation reaction and obtain an oxidation solution containing hydrogen peroxide and alkylanthraquinone; and 4) A step of extracting and separating the oxidizing solution to obtain an extract containing hydrogen peroxide and a raffinate containing alkylanthraquinone, and returning the raffinate to the hydrogenation reactor for use as part of the working solution.

[0033] According to this application, the working solution is typically a solution produced by dissolving an alkylanthraquinone compound in an organic solvent, and the alkylanthraquinone compound may be one that has been conventionally used in the art, and is not particularly limited in this application. Preferably, the alkylanthraquinone compound may be at least one selected from the group consisting of 2-alkyl-9,10-anthraquinone (i.e., 2-alkylanthraquinone), 9,10-dialkylanthraquinone (i.e., dialkylanthraquinone), and their corresponding 5,6,7,8-tetrahydro derivatives. More preferably, in the 2-alkyl-9,10-anthraquinone, the alkyl group may be a C1-C5 alkyl group, and non-limiting examples include methyl, ethyl, sec-butyl, tert-butyl, tert-amyl, and isoamyl. In the 9,10-dialkylanthraquinone, the two alkyl groups may be identical or different from each other and are independently selected from C1-C5 alkyl groups, for example, selected from methyl, ethyl, or tert-butyl. Particularly preferably, the two alkyl groups of the 9,10-dialkylanthraquinone may be 1,3-dimethyl, 1,4-dimethyl, 2,7-dimethyl, 1,3-diethyl, 2,7-di(tert-butyl), or 2-ethyl-6-tert-butyl.

[0034] According to this application, the organic solvent used in the working solution may be one that has been conventionally used in the art, and is not particularly limited in this application. In a preferred embodiment, the organic solvent is a mixture of a nonpolar compound and a polar compound. Preferably, the nonpolar compound may be a petroleum fraction having a boiling point higher than 140°C. Its main component is a C9 or higher aromatic hydrocarbon (heavily aromatic hydrocarbon), such as isomers of trimethylbenzene, tetramethylbenzene, tert-butylbenzene, methylnaphthalene, and dimethylnaphthalene. Preferably, the polar compound is selected from the group consisting of saturated alcohols, carboxylic acid esters, phosphate esters, tetrasubstituted ureas, and combinations thereof. Typically, the saturated alcohol is a C7-C11 saturated alcohol, and non-limiting examples include diisobutylcarbinol, 3,5,5-trimethylhexanol, and isoheptanol. The carboxylic acid ester is, for example, at least one of methylcyclohexyl acetate, heptyl acetate, butyl benzoate, and ethylheptanoate. The phosphate ester is, for example, at least one of trioctyl phosphate, tri-2-ethylbutyl phosphate, tri-2-ethylhexyl phosphate, and tri-n-octyl phosphate. The tetrasubstituted urea is, for example, tetra-n-butylurea.

[0035] According to this application, preferably, the hydrogenation catalyst may be any suspendable catalyst system conventionally used in the art. For example, the hydrogenation catalyst may be selected from supported catalysts and / or unsupported catalysts, preferably a supported catalyst. More preferably, the supported catalyst comprises a support and an active metal, the active metal being selected from group VIII metals, group IB metals, group IIB metals or combinations thereof, preferably platinum, rhodium, palladium, cobalt, nickel, ruthenium, copper, rhenium or combinations thereof. The support is selected from activated carbon, silicon carbide, alumina, silicon monoxide, silica, titania, zirconia, magnesia, zinc oxide, calcium carbonate, barium sulfate or combinations thereof, preferably alumina, silica or combinations thereof. Even more preferably, the hydrogenation catalyst has an active metal content of 0.01 to 30 wt%, preferably 0.01 to 5 wt%, and more preferably 0.1 to 5 wt%, based on the weight of the hydrogenation catalyst.

[0036] In a preferred embodiment, the particle size of the hydrogenation catalyst is 0.1 to 5000 μm, preferably 0.1 to 500 μm, and more preferably 1 to 200 μm.

[0037] According to this application, in step 1), the alkylanthraquinone compound in the working solution is subjected to a hydrogenation reaction with hydrogen under conditions in which hydrogenation catalyst particles are present, thereby obtaining a slurry containing hydrogenated anthraquinone, by-products, and hydrogenation catalyst particles. Here, the hydrogenated anthraquinone refers to a hydrogenation product that can produce hydrogen peroxide by oxidation, such as ethyl hydrogen anthraquinone, and the by-product refers to a hydrogenation product that cannot produce hydrogen peroxide by oxidation, such as tetrahydroalkylanthraquinone, octahydroalkylanthraquinone, decahydroalkylanthraquinone, alkylhydroxyanthrone, and alkylanthrone.

[0038] In a preferred embodiment, the hydrogenation reaction in step 1) is carried out in a slurry bed reactor to further improve the production efficiency and hydrogenation efficiency and reduce production costs. The specific form of the slurry bed reactor is not particularly limited in this application and may be, for example, a mechanically stirred kettle and other forms of reactors that provide driving force for slurry circulation by known methods such as a gas lift.

[0039] In a more preferred embodiment, the conditions for the hydrogenation reaction in step 1) include a pressure of 0.03 to 0.35 MPa, preferably 0.05 to 0.2 MPa; a temperature of 40 to 70°C, preferably 45 to 65°C; a ratio of the mass flow rate of the working solution to the mass flow rate of the hydrogenation catalyst of 25 to 700:1, preferably 30 to 500:1; and a ratio of the standard volume flow rate of hydrogen to the volume flow rate of the working solution of 4 to 14:1, preferably 5 to 10:1.

[0040] In a preferred embodiment, the ratio of the volumetric flow rate of the circulating slurry to the volumetric flow rate of the working solution in step 1) is 6 to 20:1, preferably 8 to 18:1, more preferably 12 to 18:1, for example 12 to 15:1.

[0041] In this application, the method for recovering the hydrogenation catalyst particles used in step 1) is not particularly limited, as long as the slurry can be separated by solid-liquid separation to obtain a hydrogenation solution and a circulating slurry. Here, the hydrogenation solution is an organic solution containing a hydrogenated anthraquinone compound and hydrogenation by-products, and substantially free of hydrogenation catalyst particles, and the circulating slurry is an organic slurry rich in hydrogenation catalyst particles, and may have the same composition as the hydrogenation solution except for the hydrogenation catalyst particles.

[0042] According to this application, the recovery of the hydrogenation catalyst particles used in step 1), i.e., the solid-liquid separation of the slurry, can be carried out inside or outside the hydrogenation reactor, preferably outside the hydrogenation reactor. In a preferred embodiment, the solid-liquid separation of the slurry is carried out in a filter outside the hydrogenation reactor, more preferably in an automatic backwash filter.

[0043] In a more preferred embodiment, 2 to 50, preferably 4 to 40, automatic backwash filters can be used. When multiple filters are provided, operation is more convenient, installation and maintenance are also easier, and long-term stable operation of the slurry bed reactor can be achieved. Preferably, each filter is independently equipped with a filter pressure difference detector and an automatic backwash switching valve, and the filter pressure difference can be used to enable alternating online automatic backwashing of multiple filters.

[0044] According to this application, the filter medium used in the automatic backwash filter may be made from any known filter material such as ceramic, porous metal such as sintered stainless steel, or other material. The filter medium should have a pore size that does not allow hydrogenation catalyst particles to pass through, and therefore the pore size depends on the average particle size and particle size distribution of the hydrogenation catalyst particles. For example, the pore size of the filter medium may be in the range of 0.1 to 200 μm, preferably 0.5 to 100 μm, and more preferably 0.5 to 50 μm.

[0045] According to this application, the backwash fluid used in the automatic backwash filter may be a liquid or a gas, preferably a liquid. For example, the liquid may be a fresh working solution and / or a filtered hydrogenated solution, preferably a filtered hydrogenated solution.

[0046] In a preferred embodiment, the hydrogenation reaction in step 1) also yields a hydrogen-containing tail gas, i.e., a hydrogen-containing gas remaining after the hydrogenation reaction, and step 1) further includes discharging the hydrogen-containing tail gas and / or compressing the hydrogen-containing tail gas and returning it to the hydrogenation reactor, preferably compressing the hydrogen-containing tail gas and returning it to the hydrogenation reactor, for example, compressing the hydrogen-containing tail gas and returning it to the hydrogen feed.

[0047] In this application, in order to further lower the floor temperature of the hydrogenation reactor, the temperature of the circulating slurry may be adjusted to be the same as the temperature of the hydrogenation reaction. In a preferred embodiment, step 1) further includes performing a first cooling on the circulating slurry to obtain a first cooling solution, and returning the first cooling solution to the hydrogenation reactor. More preferably, the temperature of the first cooling solution is 40 to 70°C, preferably 45 to 65°C.

[0048] According to this application, in step 2), the first stream of hydrogenation solution (also referred to as solution A in this text) comes into contact with the regeneration catalyst and reacts to regenerate at least a portion of the by-products generated by the hydrogenation reaction of alkylanthraquinone in solution A, converting them into alkylanthraquinone compounds to obtain a regenerated hydrogenation solution.

[0049] In a preferred embodiment, the ratio of the mass flow rate of the first flow of the hydrogenation solution (i.e., solution A) to the mass flow rate of the second flow of the hydrogenation solution (also referred to hereafter as solution B) is 10-50:50-90, more preferably 15-40:60-85, and even more preferably 15-30:70-85, for example, 15-25:75-85. By using such a specific ratio of mass flow rates of solution A and solution B, the regeneration efficiency of the working solution can be guaranteed, ensuring long-term stable operation of the apparatus with high hydrogenation efficiency, while also reducing the amount of regeneration catalyst used for regenerating the working solution and reducing the generation of waste solids.

[0050] In a preferred embodiment, the regeneration reaction of step 2) is carried out in a regeneration reactor, which is selected from a fixed-bed reactor, a slurry-bed reactor, or a combination thereof.

[0051] According to this application, the regeneration catalyst may be any type of regeneration catalyst commonly used in the art, and is not particularly limited as long as it can convert solution A into a regeneration hydrogenation solution. Preferably, the regeneration catalyst is selected from modified alumina, modified molecular sieves, or a combination thereof. In a preferred embodiment, if the regeneration reactor is a fixed-bed reactor, the regeneration catalyst is modified alumina, which is alumina modified with at least one metal selected from alkali metals, alkaline earth metals, and rare earth metals. If the regeneration reactor is a slurry-bed reactor, the regeneration catalyst is a modified molecular sieve, which is a molecular sieve modified with at least one metal selected from alkali metals, alkaline earth metals, and rare earth metals.

[0052] In a preferred embodiment, the conditions for the regeneration reaction include a temperature of 60 to 120°C, preferably 80 to 100°C; a pressure of 0.05 to 0.5 MPa, preferably 0.05 to 0.3 MPa; and a mass ratio of solution A to regeneration catalyst of 0.1 to 10:1, preferably 0.3 to 5:1. These preferred reaction conditions are advantageous for promoting the regeneration reaction of solution A.

[0053] In a further preferred embodiment, in order to satisfy the conditions for a regeneration reaction, step 2) further includes exchanging heat between solution A and at least a portion of the regeneration hydrogenation solution to obtain a heat exchange solution, and then carrying out a regeneration reaction on the obtained heat exchange solution. Here, in the heat exchange process, solution A is heated and the regeneration hydrogenation solution is cooled, and the heat exchange solution refers to the heated solution A.

[0054] In a more preferred embodiment, step 2) further includes heating the heat-exchanged solution and then carrying out the regeneration reaction. In this application, by heat-exchanging and heating the solution A, the solution A reaches the conditions for the regeneration reaction, and steam consumption can be saved.

[0055] In a preferred embodiment, the oxygen content of the oxygen-containing gas used in step 3) is 20 to 100% by volume. For example, the oxygen-containing gas may be selected from oxygen, air, or a mixture of oxygen and an inert gas, the inert gas may be at least one selected from nitrogen, helium, argon, and neon, preferably nitrogen. Particularly preferred is the oxygen-containing gas to be air.

[0056] According to this application, in step 3), solution B and the regenerated hydrogenation solution are brought into contact with oxygen in an oxygen-containing gas and reacted, where the hydrogenated anthraquinone is oxidized to obtain alkylanthraquinone and hydrogen peroxide, thereby obtaining the oxidation solution.

[0057] In a preferred embodiment, the oxidation reaction of step 3) is carried out in an oxidation reactor, which may be selected from the group consisting of a bubble column, a packed column, a plate column, and a stirring vessel.

[0058] In a preferred embodiment, the conditions for the oxidation reaction in step 3) include a temperature of 30 to 60°C, preferably 40 to 55°C; and a pressure of 0.1 to 0.5 MPa, preferably 0.2 to 0.5 MPa. These preferred reaction conditions are favorable for the oxidation reaction of the hydrogenation solution and improve the hydrogen peroxide content in the oxidizing solution.

[0059] In a preferred embodiment, in order to satisfy the conditions for the oxidation reaction, step 3) further includes, before the oxidation reaction, mixing solution B and the regenerating hydrogenation solution to obtain a mixed solution, and performing a second cooling on the mixed solution to obtain a second cooled solution. Preferably, the temperature of the second cooled solution is 40 to 55°C, more preferably 40 to 50°C.

[0060] According to this application, in order to avoid the decomposition of hydrogen peroxide during the oxidation process, the mixed solution obtained by mixing solution B and the regenerating hydrogenation solution, or the second cooling solution, is preferably subjected to the oxidation reaction in a slightly acidic state. In a preferred embodiment, step 3) further includes, before the oxidation reaction, a step of mixing the mixed solution or the second cooling solution with a first pH adjusting agent to obtain an adjusted solution, where the first pH adjusting agent can be selected from organic acids, inorganic acids, or combinations thereof, and is preferably an inorganic acid. The inorganic acid is preferably selected from phosphoric acid, hydrochloric acid, sulfuric acid, nitric acid, or combinations thereof, and is more preferably phosphoric acid. Even more preferably, the acid content in the adjusted solution is 1 to 10 mg / L, preferably 3 to 7 mg / L. In this application, there is no particular restriction on the amount of the first adjusting agent used, as long as the acid content in the adjusted solution satisfies the above requirements.

[0061] In a more preferred embodiment, the first pH adjusting agent exists in the form of an aqueous solution, and more preferably, the mass concentration of inorganic and / or organic acids in the aqueous solution of the first pH adjusting agent is 40-90%.

[0062] In a preferred embodiment, step 3) further includes filtering the mixed solution obtained by mixing solution B and the regenerating hydrogenation solution, the second cooling solution, or the adjustment solution before the oxidation reaction. The purpose of the filtration is to remove catalyst fine particles, particularly hydrogenation catalyst particles formed by abrasion, contained in the hydrogenation solution entering the oxidation reactor, ensuring that the amount of solid particles does not exceed 10 mg / L, and thereby guaranteeing the safety of the oxidation reactor.

[0063] In a preferred embodiment, the oxidation reaction in step 3) generates an oxygen-containing tail gas, i.e., the oxygen-containing gas remaining after the oxidation reaction, and step 3) further includes discharging the oxygen-containing tail gas and / or compressing the oxygen-containing tail gas and returning it to the oxidation reactor, preferably discharging the oxygen-containing tail gas directly after tail gas treatment. The tail gas treatment may be carried out, for example, by recovering organic matter by condensation, carbon fiber adsorption, etc., or by direct combustion.

[0064] According to this application, in step 4), the oxidizing solution is brought into contact with an extractant to perform liquid-liquid extraction, thereby obtaining an extract containing hydrogen peroxide and a raffinate containing alkylanthraquinone. Preferably, the extractant is water, and the extract is an aqueous solution of hydrogen peroxide.

[0065] In a preferred embodiment, the extraction in step 4) is carried out in an extraction column.

[0066] According to this application, in order to avoid the decomposition of hydrogen peroxide during the extraction process, the oxidizing solution is preferably extracted under slightly acidic conditions. In a preferred embodiment, the extractant used in step 4) comprises water and a second pH adjuster. The second pH adjuster is selected from organic acids, inorganic acids, or combinations thereof, preferably inorganic acids. The inorganic acid is preferably selected from phosphoric acid, hydrochloric acid, sulfuric acid, nitric acid, or combinations thereof, and more preferably phosphoric acid.

[0067] In a more preferred embodiment, the acid content in the extractant is 100 to 200 ppm, preferably 120 to 180 ppm. In this application, the amount of the second pH adjusting agent used is not particularly limited as long as the acid content in the extractant satisfies the above requirements.

[0068] In a preferred embodiment, the second pH adjusting agent exists in the form of an aqueous solution, and in the second pH adjusting agent, the mass concentration of the inorganic acid and / or organic acid is 40-90%.

[0069] In a preferred embodiment, the extraction conditions include a temperature of 25 to 60°C, preferably 40 to 50°C; and a pressure of 0.01 to 0.15 MPa, preferably 0.05 to 0.12 MPa.

[0070] In a preferred embodiment, in order to satisfy the extraction conditions, step 4) further includes performing a third cooling on the oxidizing solution before performing the extraction to obtain a third cooling solution. Preferably, the temperature of the third cooling solution is 40 to 55°C, preferably 40 to 50°C.

[0071] According to this application, the raffinate obtained in step 4) can be recycled back to step 1) for use as part of the working solution for the hydrogenation reaction. In a preferred embodiment, step 4) further includes vacuum drying the raffinate at a flow rate of at least 10% by mass to obtain a residual liquid, returning the residual liquid and the remaining raffinate together to the hydrogenation reactor, and more preferably vacuum drying the raffinate at a flow rate of at least 30% by mass.

[0072] In this application, when the raffinate is returned to the hydrogenation reactor, the circulating working solution refers to the raffinate; when the raffinate is vacuum-dried at a rate of at least 10% by mass and the resulting residual liquid and the remaining raffinate are returned to the hydrogenation reactor, the circulating working solution refers to the residual liquid and the remaining raffinate.

[0073] In a more preferred embodiment, in step 4), at least a portion of the raffinate is heated and then vacuum-dried, or at least a portion of the raffinate is heat-exchanged with a circulating working solution, then heated by a heater, and then vacuum-dried.

[0074] In a more preferred embodiment, the vacuum drying is carried out in a vacuum drying tower, which may be any known form of tower or separation vessel, such as a packed tower or sieve tower. More preferably, the conditions for the vacuum drying include a temperature of 45 to 120°C, preferably 45 to 100°C, and a pressure of -100 kPa to -50 kPa, preferably -98 kPa to -81 kPa, more preferably -98 kPa to -86 kPa.

[0075] In a more preferred embodiment, water and / or organic matter are also generated during the vacuum drying, and in order to further reduce the consumption of the extractant, step 4) further includes circulating the water and / or organic matter. Because the water and / or organic matter removed by vacuum drying is effectively utilized, there is no material loss and no wastewater is generated, making this method effective and environmentally friendly.

[0076] The inventors of this invention have discovered through their research that: by employing a specific ratio of volumetric flow rates between the circulating slurry and the working solution in combination with the regeneration reaction of a portion of the hydrogenation solution (i.e., solution A), by employing a specific ratio of mass flow rates between the portion of the hydrogenation solution and the remaining portion of the hydrogenation solution (i.e., solution B), i.e., the ratio of mass flow rates between solution A and solution B, and by returning the raffinate to the hydrogenation reaction, and in particular by vacuum drying the raffinate at a mass flow rate of at least 10%, and returning the resulting residue to the hydrogenation reaction, it is advantageous to improve the reaction selectivity and the production efficiency of the apparatus, and a high hydrogenation efficiency of 10-18 g / L can be achieved; the life of the hydrogenation catalyst can be extended, and the cost and loss due to the regeneration of the deactivation catalyst can be reduced; the inherent safety of the hydrogen peroxide generator can be improved while ensuring the stability of the hydrogenation reaction in the slurry bed, and it is environmentally friendly and effective.

[0077] In a second aspect, the present application provides a system for generating hydrogen peroxide, comprising a hydrogenation unit, a regeneration unit, an oxidation unit, and a separation unit; The hydrogenation unit is configured to hydrogenate a working solution containing alkylanthraquinone under conditions where hydrogenation catalyst particles and hydrogen are present, to obtain a slurry containing hydrogenated anthraquinone, by-products and hydrogenation catalyst particles, to recover the hydrogenation catalyst particles from the obtained slurry to obtain a circulating slurry rich in hydrogenation catalyst particles and a hydrogenation solution substantially free of hydrogenation catalyst particles, and to recirculate the circulating slurry; The regeneration unit is configured to regenerate a portion of the hydrogenation solution, convert at least a portion of the by-products contained therein into alkylanthraquinones, and generate a regenerated hydrogenation solution; The oxidation unit is configured to bring the remaining portion of the hydrogenation solution and the regenerated hydrogenation solution into contact with an oxygen-containing gas to cause an oxygen reaction, thereby obtaining an oxidation solution containing hydrogen peroxide and alkylanthraquinone; and The separation unit is configured to perform extraction and separation of the oxidation solution to obtain an extract containing hydrogen peroxide and a raffinate containing alkylanthraquinone, and to return the raffinate to the hydrogenation unit.

[0078] In a preferred embodiment, the hydrogenation unit comprises a working solution inlet, a hydrogen-containing gas inlet, a hydrogenation solution outlet, and an optionally selected hydrogen-containing tail gas outlet. The regeneration unit comprises a hydrogenation solution inlet and a regeneration hydrogenation solution outlet. The oxidation unit comprises a hydrogenation solution inlet, an oxygen-containing gas inlet, an oxidation solution outlet, and an oxygen-containing gas outlet. The separation unit comprises an oxidation solution inlet, an extractant inlet, an extract outlet, and a raffinate outlet. Here, the hydrogenation solution outlet of the hydrogenation unit communicates with the hydrogenation solution inlets of the regeneration unit and the oxidation unit, respectively; the regeneration hydrogenation solution outlet of the regeneration unit communicates with the hydrogenation solution inlet of the oxidation unit; the oxidation solution outlet of the oxidation unit communicates with the oxidation solution inlet of the separation unit; and the raffinate outlet communicates with the working solution inlet of the hydrogenation unit.

[0079] In a preferred embodiment, the hydrogenation unit includes a hydrogenation reactor and a filter in the form of a slurry bed reactor, the hydrogenation reactor including a reaction zone and a gas-liquid separation zone, and having a working solution inlet, at least one hydrogen-containing gas inlet, a circulating slurry inlet, a slurry outlet, and a hydrogen-containing tail gas outlet. The working solution, circulating slurry, and hydrogen enter the reaction column (i.e., reaction zone) of the hydrogenation reactor through the corresponding inlets and come into contact with hydrogenation catalyst particles in the reaction column to carry out a hydrogenation reaction, in which alkylanthraquinones are hydrogenated to anthraquinones and flow upward. The reaction stream flows into the gas-liquid separation zone from the top opening of the reaction column, and after gas-liquid separation, the slurry containing hydrogenated anthraquinones, by-products, and hydrogenation catalyst particles is discharged from the slurry outlet, and the hydrogen-containing tail gas is discharged from the hydrogen-containing tail gas outlet at the top of the gas-liquid separation zone. After the hydrogen-containing tail gas is selectively cooled, it enters a gas intensifier and is then returned to one of the hydrogen-containing gas inlets. The slurry from the slurry bed reactor is filtered through a filter, and the clear liquid is removed from the hydrogenation unit through the hydrogenated solution outlet. The circulating slurry that flows out from the filter's circulating slurry outlet is returned to the reactor's reaction cylinder as external circulation and continues to participate in the reaction. More preferably, the hydrogenation reactor further includes a pre-solid-liquid separation zone, in which the slurry is pre-separated before entering the filter from the slurry outlet for further separation.

[0080] In a further preferred embodiment, the hydrogenation unit further comprises a compressor which communicates with the hydrogen-containing tail gas outlet of the hydrogenation reactor and one hydrogen-containing gas inlet of the hydrogenation reactor, or the compressor which communicates with the hydrogen-containing tail gas outlet of the hydrogenation reactor and one hydrogen-containing tail gas inlet of the hydrogenation reactor in order to compress the hydrogen-containing tail gas and recycle it back into the hydrogenation reactor.

[0081] In a further preferred embodiment, the hydrogenation unit further comprises a first cooler, the first cooler communicating with the outlet of the circulating slurry of the filter and the inlet of the circulating slurry of the hydrogenation reactor, and performing a first cooling on the circulating slurry to obtain a first cooling solution, which is recycled to the hydrogenation reactor.

[0082] In a preferred embodiment, the regeneration unit includes a regeneration reactor, which has a hydrogenation solution inlet and a regeneration hydrogenation solution outlet corresponding to the hydrogenation solution inlet and regeneration hydrogenation solution outlet of the regeneration unit.

[0083] In a more preferred embodiment, the regeneration unit further comprises a heat exchanger, the heat exchanger communicating with the hydrogenation solution outlet of the hydrogenation unit, the hydrogenation solution inlet of the regeneration reactor, and the regenerated hydrogenation solution outlet of the regeneration reactor, and performing heat exchange between the regenerated hydrogenation solution (i.e., solution A) and the regenerated hydrogenation solution.

[0084] In a more preferred embodiment, the regeneration unit further comprises a heater, which communicates with the hydrogenated solution outlet of the heat exchanger and the hydrogenated solution inlet of the regeneration reactor in order to heat the hydrogenated solution after heat exchange.

[0085] In a preferred embodiment, the oxidation unit includes an oxidation reactor, which has a hydrogenation solution inlet, an oxygen-containing gas inlet, an oxidation solution outlet, and an oxygen-containing tail gas outlet corresponding to the hydrogenation solution inlet, oxygen-containing gas inlet, oxidation solution outlet, and oxygen-containing tail gas outlet of the oxidation unit.

[0086] The oxidation reactor may be any known form of reactor, such as a stirring vessel, a packed column, and a plate column. The oxidation reactor may be equipped with a gas-liquid distribution device, such as packing material, sieving plates, a gas distributor, and a liquid distributor. The gas-liquid contact method in the oxidation reactor may be forward flow, reverse flow, or cross flow.

[0087] According to this application, the oxidation reactor may be one or more units. In the case of multiple oxidation reactors, the flow to be oxidized may enter the multiple oxidation reactors in series or in parallel, and the oxygen-containing gas may also enter the multiple oxidation reactors in series or in parallel.

[0088] In this application, the oxidation reactor may be equipped with an internal or external heat exchanger, or heat exchangers may be provided between multiple oxidation reactors to remove the reaction heat generated during the oxidation reaction and to avoid overheating in the oxidation reactor. The oxidation reactor may be equipped with an internal or external gas-liquid separator for separating the oxidation solution from the oxygen-containing tail gas to avoid loss of the working solution caused by the removal of the oxidation solution from the system by gas.

[0089] In a further preferred embodiment, the oxidation unit further comprises a second cooler, the second cooler communicating with the hydrogenation solution outlet of the hydrogenation unit, the regeneration hydrogenation solution outlet of the regeneration unit, and the hydrogenation solution inlet of the oxidation reactor, and cooling the mixed solution obtained by mixing the remainder of the hydrogenation solution (i.e., solution B) and the regeneration hydrogenation solution, thereby obtaining a second cooled solution after the second cooling, which then enters the oxidation reactor.

[0090] In a more preferred embodiment, the oxidation unit further comprises a precision filter, which communicates with the outlet of the second cooler and the inlet of the hydrogenated solution of the oxidation reactor for filtering the mixed solution after the second cooling.

[0091] In a preferred embodiment, the separation unit includes an extraction column, the extraction column having an oxidation solution inlet, an extractant inlet, an extractant outlet, and a raffinate outlet that correspond to the oxidation solution inlet, extractant inlet, extractant outlet, and raffinate outlet of the separation unit.

[0092] According to this application, the extraction column may be any known type of column, such as a packed column, a sieve column, a jet column, or a pulsed packed column. A liquid distributor may be provided in the extraction column, and the oxidizing solution and the extractant come into contact in a backflow manner in the extraction column.

[0093] In a more preferred embodiment, the separation unit further comprises a third cooler, the third cooler communicating with the oxidizing solution outlet of the oxidation unit and the oxidizing solution inlet of the extraction column, providing a third cooling to the oxidizing solution, which is then introduced into the extraction column.

[0094] In this application, the first cooler, the second cooler, and the third cooler may be any known type of heat exchanger, preferably the first cooler, the second cooler, and the third cooler are each independently selected from the group consisting of fixed-tube-sheet heat exchangers, double-tube heat exchangers, plate-type heat exchangers, and coil heat exchangers, and more preferably fixed-tube-sheet heat exchangers.

[0095] In a further preferred embodiment, the separation unit further comprises a vacuum drying tower, the vacuum drying tower communicating with the raffinate outlet of the extraction tower and the working solution inlet of the hydrogenation unit, vacuum drying the raffinate at a flow rate of at least 10% by mass, and returning the resulting residual liquid and the remainder of the raffinate to the hydrogenation unit.

[0096] In a further preferred embodiment, the vacuum drying tower communicates with the extractant inlet or oxidizing solution inlet of the extraction tower, and the water and / or organic matter obtained by vacuum drying the raffinate at a flow rate of at least 10% by mass is returned to the extraction tower. Preferably, the vacuum drying tower communicates with the extractant inlet or oxidizing solution inlet of the extraction tower, and the water and / or organic matter obtained by vacuum drying the raffinate at a flow rate of at least 30% by mass is returned to the extraction tower.

[0097] Preferred embodiments of the method and system for generating hydrogen peroxide according to this application will be described below with reference to the drawings.

[0098] As shown in Figure 1, in a preferred embodiment of the method of the present application, a working solution 1 containing alkylanthraquinone and hydrogen 2 are hydrogenated in a hydrogenation reactor 3 in the presence of hydrogenation catalyst particles to obtain a slurry containing hydrogenated anthraquinone, by-products and hydrogenation catalyst particles, and hydrogen-containing tail gas 4, which is discharged and / or compressed and then returned to the hydrogenation reactor 3. The slurry is catalyst recovered by a filter 3' outside the hydrogenation reactor 3 to obtain a circulating slurry 5 rich in hydrogenation catalyst particles and a hydrogenation solution 6 substantially free of hydrogenation catalyst particles, the circulating slurry 5 is optionally cooled and returned to the hydrogenation reactor 3. The hydrogenation solution 6 is divided into two flows, namely, a first flow 7 of the hydrogenation solution (i.e., solution A) and a second flow 8 of the hydrogenation solution (i.e., solution B). Solution A(7) is regenerated in the regeneration reactor 9 to convert the by-products contained in solution A into alkylanthraquinone, and a regenerated hydrogenation solution 10 is obtained. The regenerated hydrogenation solution 10 is mixed with solution B(8) to obtain a mixed solution 11. The mixed solution 11 and oxygen-containing gas 12 are oxidized in the oxidation reactor 13 to obtain an oxidation solution 14 containing hydrogen peroxide and alkylanthraquinone, and an oxygen-containing tail gas 15. The oxidation solution 14 is extracted with an extractant 17 in the extraction column 16 to obtain an extract 18 containing hydrogen peroxide and a raffinate 19 containing alkylanthraquinone. Optionally, at least a portion of the raffinate 19 is vacuum-dried in the vacuum drying column 20 to remove water and / or some organic matter to obtain a residual liquid 21. Optionally, the removed water and / or organic matter 22 is returned to the extraction column 16. The residual liquid 21 and the remainder of the raffinate 19 are returned to the hydrogenation reactor 3 as a circulating working solution 23.

[0099] Accordingly, in the preferred embodiment shown in Figure 1, the system of the present invention includes a hydrogenation unit comprising a hydrogenation reactor 3 and a filter 3', a regeneration unit comprising a regeneration reactor 9, an oxidation unit comprising an oxidation reactor 13, and a separation unit comprising an extraction column 16 and an optional vacuum drying column 20, connected in the following order: the hydrogenation unit has a working solution inlet, a hydrogen-containing gas inlet, a hydrogenation solution outlet and an optional hydrogen-containing tail gas outlet; the regeneration unit has a hydrogenation solution inlet and a regeneration hydrogenation solution outlet; the oxidation unit has a hydrogenation solution inlet, an oxygen-containing gas inlet, an oxidation solution outlet and an oxygen-containing tail gas outlet; and the separation unit has an oxidation solution inlet, an extractant inlet, an extract outlet and a raffinate outlet; Here, the hydrogenation solution outlet of the hydrogenation unit is connected to the hydrogenation solution inlets of the regeneration unit and the oxidation unit, respectively; the regeneration hydrogenation solution outlet of the regeneration unit is connected to the hydrogenation solution inlet of the oxidation unit; the oxidation solution outlet of the oxidation unit is connected to the oxidation solution inlet of the separation unit; and the raffinate outlet of the separation unit is connected to the working solution inlet of the hydrogenation unit; The hydrogenation reactor 3 has an operating solution inlet and a hydrogen-containing gas inlet corresponding to the operating solution inlet and hydrogen-containing gas inlet of the hydrogenation unit, and also has a circulating slurry inlet, a slurry outlet and a hydrogen-containing tail gas outlet. The filter 3' has a slurry inlet, a circulating slurry outlet and a hydrogenation solution outlet corresponding to the hydrogenation solution outlet of the hydrogenation unit. Here, the slurry outlet of the hydrogenation reactor communicates with the slurry inlet of the filter, the circulating slurry outlet of the filter 3' communicates with the circulating slurry inlet of the hydrogenation reactor 3, and optionally, the hydrogen-containing tail gas outlet of the hydrogenation reactor 3 communicates with the hydrogen-containing gas inlet of the hydrogenation reactor 3.

[0100] As shown in Figure 2, in a more preferred embodiment of the method of the present application, a working solution 1 containing alkylanthraquinone and hydrogen 2 are hydrogenated in a hydrogenation reactor 3 in the presence of hydrogenation catalyst particles to obtain a slurry containing hydrogenated anthraquinone, by-products and hydrogenation catalyst particles, and hydrogen-containing tail gas 4, the hydrogen-containing tail gas 4 of which is compressed by a compressor 24 and returned to the hydrogenation reactor 3. The slurry is recovered by a filter 3' outside the hydrogenation reactor 3 to obtain a circulating slurry 5 rich in hydrogenation catalyst particles and a hydrogenation solution 6 substantially free of hydrogenation catalyst particles, the circulating slurry 5 of which is cooled by a first cooler 25 and then returned to the hydrogenation reactor 3. The hydrogenation solution 6 is divided into two flows, namely solution A7 and solution B8. Solution A7 is heat-exchanged with the regenerated hydrogenation solution 10 from the regenerated reactor 9 in the heat exchanger 26. After the heat exchange, solution A7 is heated by the heater 27 and regenerated in the regenerated reactor 9, where the by-products are converted to alkylanthraquinone to obtain the regenerated hydrogenation solution 10. After the heat exchange, the regenerated hydrogenation solution 10 is mixed with solution B8 to obtain a mixed solution 11. The mixed solution 11 is cooled in the second cooler 28 and then mixed with the first pH adjusting agent 29 to obtain an adjusted solution. After filtration with the obtained precision filter 30, it is oxidized with oxygen-containing gas 12 in the oxidation reactor 13 to obtain an oxidizing solution 14 containing hydrogen peroxide and alkylanthraquinone, and an oxygen-containing tail gas 15. The oxidizing solution 14 is cooled by the third cooler 31 and extracted with extractant 17 in the extraction column 16 to obtain an extract 18 containing hydrogen peroxide and a raffinate 19 containing alkylanthraquinone. Optionally, at least a portion of the raffinate 19 is vacuum-dried in a vacuum drying apparatus 20 to remove water and / or some organic matter to obtain a residual liquid 21, and the removed water and / or organic matter 22 is optionally returned to the extraction column 16. The residual liquid 21 and the remainder of the raffinate 19 are returned to the hydrogenation reactor 3 as a circulating working solution 23.

[0101] Therefore, in a further preferred embodiment shown in Figure 2, the system of the present application comprises a hydrogenation unit including a hydrogenation reactor 3, a filter 3', a compressor 24 and a first cooler 25, connected in the following order: a regeneration unit including a regeneration reactor 9, a heat exchanger 26 and a heater 27; an oxidation unit including an oxidation reactor 13, a second cooler 28 and a precision filter 30; and a separation unit including an extraction column 16, a third cooler 31 and an optional vacuum drying column 20; The hydrogenation reactor 3 has an operating solution inlet and a hydrogen-containing gas inlet corresponding to the operating solution inlet and hydrogen-containing gas inlet of the hydrogenation unit, and also has a circulating slurry inlet, a slurry outlet and a hydrogen-containing tail gas outlet; the filter 3' has a slurry inlet, a circulating slurry outlet and a hydrogenation solution outlet corresponding to the hydrogenation solution outlet of the hydrogenation unit; the slurry outlet of the hydrogenation reactor 3 is connected to the slurry inlet of the filter 3'; the hydrogen-containing tail gas outlet of the hydrogenation reactor 3 is connected to the hydrogen-containing gas inlet of the hydrogenation reactor 3 through the compressor 24; and the circulating slurry outlet of the filter 3' is connected to the circulating slurry inlet of the hydrogenation reactor through the first cooler 25; The regeneration reactor 9 has a hydrogenation solution inlet and a regeneration hydrogenation solution outlet corresponding to the hydrogenation solution inlet and regeneration hydrogenation solution outlet of the regeneration unit; the heat exchanger 26 is in communication with the hydrogenation solution outlet of the hydrogenation unit, the hydrogenation solution inlet of the regeneration reactor, and the regeneration hydrogenation solution outlet of the regeneration reactor; and the heater 27 is in communication with the hydrogenation solution outlet of the heat exchanger 26 and the hydrogenation solution inlet of the regeneration reactor 9; The oxidation reactor 13 has a hydrogenation solution inlet, an oxygen-containing gas inlet, an oxidation solution outlet, and an oxygen-containing tail gas outlet corresponding to the hydrogenation solution inlet, oxygen-containing gas inlet, oxidation solution outlet, and oxygen-containing tail gas outlet of the oxidation unit, the second cooler 28 is in communication with the hydrogenation solution outlet of the hydrogenation unit, the regeneration hydrogenation solution outlet of the regeneration unit, and the precision filter 30, the precision filter 30 is in communication with the outlet of the second cooler 28 and the hydrogenation solution inlet of the oxidation reactor; The extraction column 16 has an oxidation solution inlet, an extractant inlet, an extractant outlet, and a raffinate outlet corresponding to the oxidation solution inlet, extractant inlet, extractant outlet, and raffinate outlet of the separation unit, the third cooler 31 is in communication with the oxidation solution outlet of the oxidation unit and the oxidation solution inlet of the extraction column, the vacuum drying column 20 is in communication with the raffinate outlet of the extraction column 16 and the working solution inlet of the hydrogenation unit, and optionally the vacuum drying column is further in communication with the extractant inlet or oxidation solution inlet of the extraction column. [Examples]

[0102] The present application will be described in detail below with reference to examples, but the present application is not limited to these examples.

[0103] In the following examples and comparative examples, the hydrogenation catalyst was a supported catalyst, where the support was alumina and the active metal was palladium, and the content of the active metal was 2 wt% based on the weight of the hydrogenation catalyst.

[0104] In the following examples and comparative examples, the working solution consists of a heavy aromatic compound, trioctyl phosphate, ethylanthraquinone, tetrahydroethylanthraquinone, and amirantraquinone in a mass ratio of 59:21:9:6:5.

[0105] In the following examples and comparative examples, the method for measuring hydrogenation efficiency is as follows: 5 mL of hydrogenation solution is placed in a separatory funnel, 10 mL of heavy aromatic compound and 20 mL of 1+4H2SO4 solution (volume ratio of H2SO4 to water: 1:4) are added, O2 is passed through the mixed solution to induce foaming, and the mixture is oxidized until the color of the mixed solution becomes bright yellow or orange-yellow (approximately 10-15 mins). The reaction solution is washed and extracted 4-5 times with pure water, each time with approximately 20 mL of water, and the extract is titrated with 0.1 mol / L KMnO4 standard solution until it turns a light red color, stopping when the color does not fade after 30 seconds.

[0106] Calculation method: Hydrogenation efficiency (g / L) = Concentration of KMnO4 standard solution (0.1 mol / L) × Volume of KMnO4 standard solution (mL) × 17.01 / 5.

[0107] In the following examples and comparative examples, hydrogenation selectivity was calculated as follows.

[0108] Hydrogenation selectivity = Measured hydrogenation efficiency / Theoretically calculated hydrogenation efficiency The theoretically calculated hydrogenation efficiency = Volume of hydrogen consumed / 22.4 × 34.02 / Volume of working solution.

[0109] [Example 1] (1) Under conditions where a hydrogenation catalyst is present, 42 Nm³ of hydrogen is supplied to the slurry bed reactor through the hydrogen-containing gas inlet. 3 A hydrogen of 4.8 m³ is supplied to the slurry bed reactor through the corresponding inlet. 3 / h working solution and 57.6m 3 A circulating slurry was supplied at a rate of 1 / h, where the diameter of the reaction cylinder in the slurry bed reactor was 300 mm. The hydrogenation reaction was carried out at a temperature of 60°C, a pressure of 0.3 MPa, and a ratio of the mass flow rate of the working solution to the mass flow rate of the hydrogenation catalyst of 110:1, yielding slurry and hydrogen-containing tail gas.

[0110] The slurry was filtered through three filters connected in parallel, and the hydrogenation solution was used as the backwash liquid. Continuous automatic backwashing was performed using an automatic backwashing program to obtain the hydrogenation solution and the circulating slurry. The filtered circulating slurry, rich in catalyst particles, was cooled to 59.3°C using a first cooler and recirculated to the reaction cylinder of the slurry bed reactor to continue the reaction. Here, the volume flow rate ratio of the circulating slurry to the working solution was 12:1.

[0111] (2) A regenerated hydrogenated solution was obtained by regenerating solution A (hydrogenated solution at a 15% mass flow rate) through a hydrogenated clay bed (800 mm in diameter, 1500 mm in height) filled with activated alumina. Here, the regeneration reaction temperature was 90°C, the pressure was the spontaneous generation pressure, and the mass ratio of solution A to the regenerated catalyst was 2:1.

[0112] (3) The mixed solution of the regenerated hydrogenation solution obtained in step 2) and solution B (hydrogenation solution at 85% mass flow rate) was cooled to 45°C in a second cooler to obtain a second coolant, to which a phosphoric acid solution with a mass concentration of 85% was injected to obtain a controlled solution with a phosphoric acid content of 5 mg / L. The controlled solution was filtered through a microfilter and then supplied to an oxidation reactor, where it was heated at a temperature of 50°C and a pressure of 0.3 MPa at a rate of 260 Nm 3 An oxidation reaction was carried out with air at a rate of / h to obtain an oxygen-containing tail gas and an oxidation solution.

[0113] (4) An 85% mass concentration aqueous phosphoric acid solution was diluted with an acidic aqueous solution containing 120 ppm phosphoric acid. The oxidizing solution and the acidic aqueous solution were extracted in an extraction column at an extraction temperature of 50°C, with a column top pressure of atmospheric pressure and a mass flow rate ratio of 25:1 to obtain a hydrogen peroxide solution and raffinate.

[0114] (5) The raffinate was dehydrated in a vacuum drying tower, and the resulting residual liquid was recirculated to the hydrogenation reaction unit as a circulating working solution. Here, the pressure in the vacuum drying tower was -96 kPa and the temperature was 70°C.

[0115] Experimental results: The axial heating rate of the slurry bed reactor was 0.9°C, the hydrogenation efficiency of the hydrogenation solution was 13-13.2 g / L, the hydrogenation selectivity was >99%, the apparatus was operated for 3200 hours, and a total of 560 tons of 35% mass concentration hydrogen peroxide solution were obtained. During this time, 1 ton of activated alumina was replaced. The catalyst activity and selectivity in the slurry bed reactor were stable, no loss of activity was observed, and the content of active anthraquinones (i.e., ethylanthraquinone, tetrahydroethylanthraquinone, amilanthraquinone) in the reaction solution in the slurry bed reactor was stable.

[0116] [Example 2] (1) Under conditions where a hydrogenation catalyst is present, 39 Nm³ of gas is introduced into the slurry bed reactor through the gas inlet. 3 A hydrogen of 4.8 m³ is supplied to the slurry bed reactor through the corresponding inlet. 3 / h working solution and 28.8m 3A circulating slurry was supplied at a rate of / h, where the diameter of the reaction cylinder in the slurry bed reactor was 300 mm. The hydrogenation reaction was carried out under hydrogenation reaction conditions of 60°C, 0.3 MPa, and a ratio of the mass flow rate of the working solution to the mass flow rate of the hydrogenation catalyst of 110:1, yielding slurry and hydrogen-containing tail gas.

[0117] The slurry is filtered through four filters connected in parallel, and the hydrogenation solution is used as the backwash liquid. Continuous automatic backwashing is performed using an automatic backwashing program to obtain the hydrogenation solution and the circulating slurry. The filtered circulating slurry, rich in catalyst particles, is cooled to 58.5°C by a first cooler and recirculated to the reaction cylinder to continue the reaction. Here, the volume flow rate ratio of the circulating slurry to the working solution was 6:1.

[0118] (2) A regenerated hydrogenated solution was obtained by regenerating solution A (hydrogenated solution at a 15% mass flow rate) through a hydrogenated clay bed (800 mm in diameter, 1500 mm in height) filled with activated alumina. Here, the regeneration reaction temperature was 90°C, the pressure was the spontaneous generation pressure, and the mass ratio of solution A to the regenerated catalyst was 2:1.

[0119] (3) The mixed solution of the regenerated hydrogenation solution obtained in step 2) and solution B (hydrogenation solution at 85% mass flow rate) was cooled to 45°C in a second cooler to obtain a second coolant, to which a phosphoric acid solution with a mass concentration of 85% was injected to obtain a controlled solution with a phosphoric acid content of 5 mg / L. The controlled solution was filtered through a microfilter and then supplied to an oxidation reactor, where it was heated at a temperature of 48°C and a pressure of 0.3 MPa at a rate of 230 Nm 3 An oxidation reaction was carried out with air at a rate of / h to obtain an oxygen-containing tail gas and an oxidation solution.

[0120] (4) An 85% mass concentration aqueous phosphoric acid solution was diluted with an acidic aqueous solution containing 150 ppm phosphoric acid, and the oxidizing solution and the acidic aqueous solution were extracted in an extraction column at a mass flow rate ratio of 27:1 to obtain a hydrogen peroxide solution and raffinate.

[0121] (5) The raffinate was dehydrated in a vacuum drying column, and the resulting residual liquid was recycled as the circulating working solution to the hydrogenation reaction unit. Here, the pressure of the vacuum drying column was -96 kPa and the temperature was 50 °C.

[0122] Experimental results: The axial temperature rise of the slurry bed reactor was 1.5 °C, the hydrogenation efficiency of the hydrogenation solution was 11.7 - 11.8 g / L, the hydrogen addition selectivity > 98%, the device was operated for 3200 h, and a total of 506 t of hydrogen peroxide solution with a mass concentration of 35% was obtained. During that time, 1.3 t of activated alumina was replaced. The activity and selectivity of the catalyst in the slurry bed reactor were stable, no activity loss phenomenon was observed, and the content of effective anthraquinone in the working solution was relatively stable.

[0123] [Example 3] (1) Under the condition of the presence of a hydrogen addition catalyst, 35 Nm 3 / h of hydrogen was supplied to the slurry bed reactor through the gas inlet, 4.8 m 3 / h of the working solution and 38.4 m 3 / h of the circulating slurry were supplied to the slurry bed reactor through the corresponding inlets. Here, the diameter of the reaction cylinder in the slurry bed reactor was 300 mm, and the hydrogenation reaction was carried out under the hydrogenation reaction conditions of 60 °C, 0.3 MPa, and a ratio of the mass flow rate of the working solution to the mass flow rate of the hydrogen addition catalyst of 110:1, and a slurry and a hydrogen-containing tail gas were obtained.

[0124] The slurry was filtered through three filters connected in parallel, the hydrogenation solution was used as the backwashing liquid, and continuous automatic backwashing was carried out using an automatic backwashing program to obtain a hydrogenation solution and a circulating slurry. The circulating slurry rich in catalyst fine particles was cooled to 59 °C by a first cooler and recycled to the reaction cylinder to continue to participate in the reaction. Here, the volume flow rate ratio of the circulating slurry to the working solution was 8:1.

[0125] (2) A regenerated hydrogenated solution was obtained by regenerating solution A (hydrogenated solution at a 10% mass flow rate) through a hydrogenated clay bed (800 mm in diameter, 1500 mm in height) filled with activated alumina. Here, the regeneration reaction temperature was 60°C, the pressure was the spontaneous generation pressure, and the mass ratio of solution A to the regenerated catalyst was 2:1.

[0126] (3) The mixed solution of the regenerated hydrogenation solution obtained in step 2) and solution B (hydrogenation solution at a 90% mass flow rate) was cooled to 45°C in a second cooler to obtain a second coolant, to which a phosphoric acid solution with a mass concentration of 85% was injected to obtain a controlled solution with a phosphoric acid content of 5 mg / L. The controlled solution was filtered through a microfilter and then supplied to an oxidation reactor, where it was heated at a temperature of 48°C and a pressure of 0.3 MPa, at a rate of 209 Nm 3 An oxidation reaction was carried out with air at a rate of / h to obtain an oxygen-containing tail gas and an oxidation solution.

[0127] (4) An 85% mass concentration aqueous phosphoric acid solution was diluted with an acidic aqueous solution containing 180 ppm phosphoric acid, and the oxidizing solution and the acidic aqueous solution were extracted in an extraction column at a mass flow rate ratio of 30:1 to obtain a hydrogen peroxide solution and raffinate.

[0128] (5) The raffinate was dehydrated in a vacuum drying tower, and the resulting residual liquid was recirculated to the hydrogenation reaction unit as a circulating working solution. Here, the pressure in the vacuum drying tower was -96 kPa and the temperature was 50°C.

[0129] Experimental results: The axial heating of the reactor was 1.2°C, the hydrogenation efficiency of the hydrogenation solution was 10.7-10.8 g / L, and the hydrogenation selectivity was 98.5%. The apparatus was operated for 3200 hours, yielding a total of 468 tons of 35% mass concentration hydrogen peroxide solution. During this time, 1.3 tons of activated alumina were replaced. The catalyst activity in the slurry bed reactor decreased by 13%, the selectivity decreased by 1.4%, indicating a loss of activity, and the content of active anthraquinone in the working solution decreased by 5%.

[0130] [Example 4] (1) Under conditions where a hydrogenation catalyst is present, 42 Nm³ of hydrogen is supplied to the slurry bed reactor through the hydrogen-containing gas inlet. 3A hydrogen of 4.8 m³ is supplied to the slurry bed reactor through the corresponding inlet. 3 / h working solution and 86.4m 3 A circulating slurry was supplied at a rate of 1 / h, where the diameter of the reaction cylinder in the slurry bed reactor was 300 mm. The hydrogenation reaction was carried out under hydrogenation conditions of a temperature of 60°C, a pressure of 0.3 MPa, and a ratio of the mass flow rate of the working solution to the mass flow rate of the hydrogenation catalyst of 110:1, yielding slurry and hydrogen-containing tail gas.

[0131] The slurry is filtered through three filters connected in parallel, and the hydrogenation solution is used as the backwash liquid. Continuous automatic backwashing is performed using an automatic backwashing program to obtain the hydrogenation solution and the circulating slurry. The filtered circulating slurry, rich in catalyst particles, is cooled by a first cooler and recirculated to the reaction cylinder of the slurry bed reactor to continue the reaction. Here, the volume flow rate ratio of the circulating slurry to the working solution was 18:1.

[0132] (2) A regenerated hydrogenated solution was obtained by regenerating solution A (hydrogenated solution at a 15% mass flow rate) through a hydrogenated clay bed (800 mm in diameter, 1500 mm in height) filled with activated alumina. Here, the regeneration reaction temperature was 90°C, the pressure was the spontaneous generation pressure, and the mass ratio of solution A to the regenerated catalyst was 2:1.

[0133] (3) The mixed solution of the regenerated hydrogenation solution obtained in step 2) and solution B (hydrogenation solution at 85% mass flow rate) was cooled to 45°C in a second cooler to obtain a second coolant, to which a phosphoric acid solution with a mass concentration of 85% was injected to obtain a controlled solution with a phosphoric acid content of 5 mg / L. The controlled solution was filtered through a microfilter and then supplied to an oxidation reactor, where it was heated at a temperature of 50°C and a pressure of 0.3 MPa at a rate of 260 Nm 3 An oxidation reaction was carried out with air at a rate of / h to obtain an oxygen-containing tail gas and an oxidation solution.

[0134] (4) An 85% mass concentration aqueous phosphoric acid solution was diluted with an acidic aqueous solution containing 120 ppm phosphoric acid. The oxidizing solution and the acidic aqueous solution were extracted in an extraction column at an extraction temperature of 50°C, with atmospheric pressure at the top of the column and a mass flow rate ratio of 25:1 to obtain a hydrogen peroxide solution and raffinate.

[0135] (5) The raffinate was dehydrated in a vacuum drying tower, and the resulting residual liquid was recirculated to the hydrogenation reaction unit as a circulating working solution. Here, the pressure in the vacuum drying tower was -96 kPa and the temperature was 70°C.

[0136] Experimental results of the technical effect: The axial heating of the slurry bed reactor was 0.7°C, the hydrogenation efficiency of the hydrogenation solution was 13-13.2 g / L, the hydrogenation selectivity was >99%, the apparatus was operated for 3200 hours, and a total of 560 tons of 35% mass concentration hydrogen peroxide solution were obtained. During this time, 700 kg of activated alumina was replaced. The catalyst activity and selectivity in the slurry bed reactor were stable, no loss of activity was observed, and the effective anthraquinone content in the reaction solution in the slurry bed reactor was stable.

[0137] [Example 5] (1) Under conditions where a hydrogenation catalyst is present, 40 Nm³ of hydrogen is introduced into the slurry bed reactor through the hydrogen-containing gas inlet. 3 A hydrogen of 4.8 m³ is supplied to the slurry bed reactor through the corresponding inlet. 3 / h working solution and 57.6m 3 A circulating slurry was supplied at a rate of 1 / h, where the diameter of the reaction cylinder in the slurry bed reactor was 300 mm. The hydrogenation reaction was carried out under hydrogenation conditions of a temperature of 60°C, a pressure of 0.3 MPa, and a ratio of the mass flow rate of the working solution to the mass flow rate of the hydrogenation catalyst of 110:1, yielding slurry and hydrogen-containing tail gas.

[0138] The slurry is filtered through three filters connected in parallel, and the hydrogenation solution is used as the backwash liquid. Continuous automatic backwashing is performed using an automatic backwashing program to obtain the hydrogenation solution and the circulating slurry. The filtered circulating slurry, rich in catalyst particles, is cooled by a first cooler and recirculated to the reaction cylinder of the slurry bed reactor to continue the reaction. Here, the volume flow rate ratio of the circulating slurry to the working solution was 12:1.

[0139] (2) A regenerated hydrogenated solution was obtained by regenerating solution A (hydrogenated solution at a 40% mass flow rate) through a hydrogenated clay bed (800 mm in diameter, 1500 mm in height) filled with activated alumina. Here, the regeneration reaction temperature was 90°C, the pressure was the spontaneous generation pressure, and the mass ratio of solution A to the regenerated catalyst was 5.3:1.

[0140] (3) The mixed solution of the regenerated hydrogenation solution obtained in step 2) and solution B (hydrogenation solution at a mass flow rate of 60%) was cooled to 45°C in a second cooler to obtain a second coolant, to which a phosphoric acid solution with a mass concentration of 85% was injected to obtain a controlled solution with a phosphoric acid content of 5 mg / L. The controlled solution was filtered through a microfilter and then supplied to an oxidation reactor, where it was heated at a temperature of 50°C and a pressure of 0.3 MPa, at a rate of 238 Nm 3 An oxidation reaction was carried out with air at a rate of / h to obtain an oxygen-containing tail gas and an oxidation solution.

[0141] (4) An 85% mass concentration aqueous phosphoric acid solution was diluted with an acidic aqueous solution containing 120 ppm phosphoric acid. The oxidizing solution and the acidic aqueous solution were extracted in an extraction column at an extraction temperature of 50°C, with atmospheric pressure at the top of the column and a mass flow rate ratio of 26:1 to obtain a hydrogen peroxide solution and raffinate.

[0142] (5) The raffinate was dehydrated in a vacuum drying tower, and the resulting residual liquid was recirculated to the hydrogenation reaction unit as a circulating working solution. Here, the pressure in the vacuum drying tower was -96 kPa and the temperature was 70°C.

[0143] Experimental results of the technical effect: The axial heating of the slurry bed reactor was 0.9°C, the hydrogenation efficiency of the hydrogenation solution was 12-12.2 g / L, the hydrogenation selectivity was >98.7%, the apparatus was operated for 3200 hours, and a total of 526 tons of 35% mass concentration hydrogen peroxide solution were obtained. During this time, 1.3 tons of activated alumina were replaced. The catalyst activity and selectivity in the slurry bed reactor were stable, no loss of activity was observed, and the effective anthraquinone content in the reaction solution in the slurry bed reactor was stable.

[0144] [Comparative Example 1] (1) Under conditions where a hydrogenation catalyst is present, 24.5 Nm³ is supplied to the slurry bed reactor through the gas inlet. 3 A hydrogen of 4.8 m³ is supplied to the slurry bed reactor through the corresponding inlet. 3 / h working solution and 38.4m 3 A circulating slurry was supplied at a rate of / h, where the diameter of the reaction cylinder in the slurry bed reactor was 300 mm. The hydrogenation reaction was carried out under hydrogenation reaction conditions of 60°C, 0.3 MPa, and a ratio of the mass flow rate of the working solution to the mass flow rate of the hydrogenation catalyst of 110:1, yielding slurry and hydrogen-containing tail gas.

[0145] The slurry is filtered through three filters connected in parallel, and the hydrogenation solution is used as the backwash liquid. Continuous automatic backwashing is performed using an automatic backwashing program to obtain the hydrogenation solution and the circulating slurry. The filtered circulating slurry, rich in catalyst particles, is cooled by a first cooler and recirculated to the reaction cylinder to continue the reaction. Here, the volume flow rate ratio of the circulating slurry to the working solution is 8:1, and the hydrogenation solution enters the oxidation unit directly without being regenerated.

[0146] (2) The hydrogenation solution obtained in step 1) was cooled to 45°C in a second cooler to obtain a second coolant, to which a phosphoric acid solution with a mass concentration of 85% was injected to obtain a controlled solution with a phosphoric acid content of 5 mg / L. The controlled solution was filtered through a microfilter and then supplied to an oxidation reactor, where it was heated at a temperature of 45°C and a pressure of 0.3 MPa, at a rate of 145 Nm 3 An oxidation reaction was carried out with air at a rate of / h to obtain an oxygen-containing tail gas and an oxidation solution.

[0147] (3) An 85% mass concentration aqueous phosphoric acid solution was diluted with an acidic aqueous solution containing 185 ppm phosphoric acid, and the oxidizing solution and the acidic aqueous solution were extracted in an extraction column at a mass flow rate ratio of 35:1 to obtain a hydrogen peroxide solution and raffinate.

[0148] (5) The raffinate was dehydrated in a vacuum drying tower, and the resulting residual liquid was recirculated to the hydrogenation reaction unit as a circulating working solution. Here, the pressure in the vacuum drying tower was -96 kPa and the temperature was 50°C.

[0149] Experimental results: The hydrogenation efficiency of the hydrogenation solution was only maintained at 7.1-7.3 g / L, with a hydrogenation selectivity of <97%. After 300 hours of operation, a total of 37 tons of hydrogen peroxide solution with a mass concentration of 27.5% was obtained. The catalyst activity in the slurry bed reactor decreased by 20%, and the selectivity decreased by 1.8%, indicating a clear loss of activity. The active anthraquinone content in the working solution decreased by 10%.

[0150] [Comparative Example 2] (1) Under conditions where a hydrogenation catalyst is present, 33 Nm³ of gas is introduced into the slurry bed reactor through the gas inlet. 3 A hydrogen of 4.8 m³ is supplied to the slurry bed reactor through the corresponding inlet. 3 / h working solution and 38.4m 3 A circulating slurry was supplied at a rate of / h, where the diameter of the reaction cylinder in the slurry bed reactor was 300 mm. The hydrogenation reaction was carried out under hydrogenation reaction conditions of 60°C, 0.3 MPa, and a ratio of the mass flow rate of the working solution to the mass flow rate of the hydrogenation catalyst of 110:1, yielding slurry and hydrogen-containing tail gas.

[0151] The slurry is filtered through three filters connected in parallel, and the hydrogenation solution is used as the backwash liquid. Continuous automatic backwashing is performed using an automatic backwashing program to obtain the hydrogenation solution and the circulating slurry. The filtered circulating slurry, rich in catalyst particles, is cooled by a first cooler and recirculated to the reaction cylinder to continue the reaction. Here, the volume flow rate ratio of the circulating slurry to the working solution is 8:1, and the hydrogenation solution enters the oxidation unit directly without being regenerated.

[0152] (2) The hydrogenation solution obtained in step 1) was cooled to 45°C in a second cooler to obtain a second coolant, to which a phosphoric acid solution with a mass concentration of 85% was injected to obtain a controlled solution with a phosphoric acid content of 5 mg / L. The controlled solution was filtered through a microfilter and then supplied to an oxidation reactor, where it was heated at a temperature of 50°C and a pressure of 0.3 MPa, at a rate of 195 Nm 3 An oxidation reaction was carried out with air at a rate of / h to obtain an oxygen-containing tail gas and an oxidation solution.

[0153] (3) An 85% mass concentration aqueous phosphoric acid solution was diluted with an acidic aqueous solution containing 180 ppm phosphoric acid, and the oxidizing solution and the acidic aqueous solution were extracted in an extraction column at a mass flow rate ratio of 26:1 to obtain a hydrogen peroxide solution and raffinate.

[0154] (4) The raffinate was dehydrated in a vacuum drying tower, and the resulting residual liquid was recirculated to the hydrogenation reaction unit as a circulating working solution. Here, the pressure in the vacuum drying tower was -96 kPa and the temperature was 50°C.

[0155] (5) The circulating working solution obtained in step 4) is passed through four working solution regeneration reactors connected in parallel, and the resulting regenerated working solution is recirculated to the hydrogenation reactor. Here, the regeneration reactor is a hydrogenated clay bed (800 mm in diameter, 1500 mm in height) filled with activated alumina, and the regeneration reaction temperature was 60°C.

[0156] Experimental results: The hydrogenation efficiency of the hydrogenation solution was maintained at 9.8-10 g / L, with hydrogenation selectivity <98%. The apparatus was operated for 300 hours, yielding a total of 50 tons of hydrogen peroxide solution with a mass concentration of 27.5%. The catalyst activity in the slurry bed reactor decreased by 19%, and selectivity decreased by 1.8%, indicating a clear loss of activity. The active anthraquinone content in the working solution decreased by 5%.

[0157] [Comparative Example 3] (1) Under conditions where a hydrogenation catalyst is present, 33 Nm³ of gas is introduced into the slurry bed reactor through the gas inlet. 3 A hydrogen of 4.8 m³ is supplied to the slurry bed reactor through the corresponding inlet.3 A working solution was supplied at a rate of / h, where the diameter of the reaction cylinder in the slurry bed reactor was 300 mm. The hydrogenation reaction was carried out under hydrogenation conditions of 60°C, 0.3 MPa, and a ratio of the mass flow rate of the working solution to the mass flow rate of the hydrogenation catalyst of 110:1, yielding slurry and hydrogen-containing tail gas.

[0158] The slurry was filtered using an internal filter, the hydrogenation solution was used as the backwash liquid, and continuous automatic backwashing was performed using an automatic backwashing program. The solution was then filtered to obtain the hydrogenation solution. The reaction temperature was controlled by an internal coil cooler.

[0159] (2) A solution (hydrogenated solution at a 15% mass flow rate) was regenerated through a hydrogenated clay bed (800 mm in diameter, 1500 mm in height) filled with activated alumina to obtain a regenerated hydrogenated solution. The regeneration reaction temperature was 90°C.

[0160] (3) The mixed solution of the regenerated hydrogenation solution obtained in step 2) and solution B (hydrogenation solution at 85% mass flow rate) was cooled to 45°C in a second cooler to obtain a second coolant, to which a phosphoric acid solution with a mass concentration of 85% was injected to obtain a controlled solution with a phosphoric acid content of 5 mg / L. The controlled solution was filtered through a microfilter and then supplied to an oxidation reactor, where it was heated at a temperature of 50°C and a pressure of 0.3 MPa, at a rate of 195 Nm 3 An oxidation reaction was carried out with air at a rate of / h to obtain an oxygen-containing tail gas and an oxidation solution.

[0161] (4) An 85% mass concentration aqueous phosphoric acid solution was diluted with an acidic aqueous solution containing 150 ppm phosphoric acid, and the oxidizing solution and the acidic aqueous solution were extracted in an extraction column at a mass flow rate ratio of 26:1 to obtain a hydrogen peroxide solution and raffinate.

[0162] (5) The raffinate was dehydrated in a vacuum drying tower, and the resulting residual liquid was recirculated to the hydrogenation reaction unit as a circulating working solution. Here, the pressure in the vacuum drying tower was -96 kPa and the temperature was 70°C.

[0163] Experimental results: The reactor was heated axially by 5°C, the hydrogenation efficiency of the hydrogenation solution was only 9.8-9.9 g / L, and the hydrogenation selectivity was <97%. The apparatus was operated for 300 hours, and a total of 50 tons of 27.5% mass concentration hydrogen peroxide solution were obtained. During this time, 500 kg of activated alumina was replaced. The catalyst activity in the slurry bed reactor decreased by 15%, the selectivity decreased by 1.5%, indicating a loss of activity phenomenon, and the effective anthraquinone content in the working solution decreased by 5%.

[0164] [Comparative Example 4] (1) Under conditions where a hydrogenation catalyst is present, 34 Nm³ of gas is introduced into the slurry bed reactor through the gas inlet. 3 A hydrogen of 4.8 m³ is supplied to the slurry bed reactor through the corresponding inlet. 3 / h working solution and 19m 3 A circulating slurry was supplied at a rate of / h, where the diameter of the reaction cylinder in the slurry bed reactor was 300 mm. The hydrogenation reaction was carried out under hydrogenation reaction conditions of 60°C and 0.3 MPa to obtain slurry and hydrogen-containing tail gas.

[0165] The slurry is filtered through three filters connected in parallel, and the hydrogenation solution is used as the backwash liquid. Continuous automatic backwashing is performed using an automatic backwashing program to obtain the hydrogenation solution and the circulating slurry. The filtered circulating slurry, rich in catalyst particles, is cooled by a first cooler and recirculated to the reaction cylinder to continue the reaction. Here, the volume flow rate ratio of the circulating slurry to the working solution was 4:1.

[0166] (2) A regenerated hydrogenated solution was obtained by regenerating solution A (hydrogenated solution at a 15% mass flow rate) through a hydrogenated clay bed (800 mm in diameter, 1500 mm in height) filled with activated alumina. Here, the regeneration reaction temperature was 90°C, the pressure was the spontaneous generation pressure, and the mass ratio of solution A to the regenerated catalyst was 2:1.

[0167] (3) The mixed solution of the regenerated hydrogenation solution obtained in step 2) and solution B (hydrogenation solution at 85% mass flow rate) was cooled to 45°C in a second cooler to obtain a second coolant, to which a phosphoric acid solution with a mass concentration of 85% was injected to obtain a controlled solution with a phosphoric acid content of 5 mg / L. The controlled solution was filtered through a microfilter and then supplied to an oxidation reactor, where it was heated at a temperature of 48°C and a pressure of 0.3 MPa, at a rate of 205 Nm 3 An oxidation reaction was carried out with air at a rate of / h to obtain an oxygen-containing tail gas and an oxidation solution.

[0168] (4) An 85% mass concentration aqueous phosphoric acid solution was diluted with an acidic aqueous solution containing 150 ppm phosphoric acid, and the oxidizing solution and the acidic aqueous solution were extracted in an extraction column at a mass flow rate ratio of 25:1 to obtain a hydrogen peroxide solution and raffinate.

[0169] (5) The raffinate was dehydrated in a vacuum drying tower, and the resulting residual liquid was recirculated to the hydrogenation reaction unit as a circulating working solution. Here, the pressure in the vacuum drying tower was -96 kPa and the temperature was 50°C.

[0170] Experimental results: The axial heating of the reactor was 3-4°C, the hydrogenation efficiency of the hydrogenation solution was only 10.4-10.5 g / L, and the hydrogenation selectivity was <97%. The apparatus was operated for 300 hours, and a total of 52 tons of 27.5% mass concentration hydrogen peroxide solution were obtained. During this time, 350 kg of activated alumina was replaced. The catalyst activity in the slurry bed reactor decreased by 14%, and the selectivity decreased by 1.3%, indicating a loss of activity phenomenon. The active anthraquinone content in the working solution remained relatively stable.

[0171] [Comparative Example 5] (1) 22 Nm 3 Pure hydrogen at / h, 4.8m 3 The working solution at 1 / h was reacted in a fixed-bed reactor (300 mm in diameter, 8000 mm in height, filled with hydrogenation catalyst particles with an average particle size of 3-5 mm) under reaction conditions of 40-60°C and 0.3 MPa. After reaction, gas-liquid separation was performed, and the hydrogen-containing tail gas was discharged to the outside.

[0172] (2) A regenerated hydrogenated solution was obtained by regenerating solution A (hydrogenated solution at a 15% mass flow rate) through a hydrogenated clay bed (800 mm in diameter, 1500 mm in height) filled with activated alumina. Here, the regeneration reaction temperature was 90°C, the pressure was the spontaneous generation pressure, and the mass ratio of solution A to the regenerated catalyst was 2:1.

[0173] (3) A portion of the mixed solution of the regenerated hydrogenation solution obtained in step 2) and solution B (hydrogenation solution at 85% mass flow rate) was recirculated to the reactor after heat removal, and the remaining portion of the mixed solution was cooled to 45°C to obtain a second coolant, to which a phosphoric acid solution with a mass fraction of 85% was injected to obtain a regulated solution with a phosphoric acid content of 5 mg / L. The regulated solution was supplied to the oxidation reactor, and in the oxidation reactor, 100 Nm 3 The reaction was carried out with air at 1 / h to obtain an oxidation solution containing hydrogen peroxide.

[0174] (4) An 85% mass concentration aqueous phosphoric acid solution was diluted with an acidic aqueous solution containing 150 ppm phosphoric acid, and the oxidizing solution and the acidic aqueous solution were extracted in an extraction column at a mass flow rate ratio of 38:1 to obtain a 27.5% hydrogen peroxide solution as the final product. The raffinate was dehydrated in a combiner and supplied to a potassium carbonate drying column for further dehydration and regeneration. The regeneration process was then carried out in three working solution clay beds (800 mm in diameter, 1500 mm in height) packed with activated alumina, and finally it was recycled to a hydrogenation reactor.

[0175] Experimental results: The temperature rise at the inlet and outlet of the bed layer of the fixed-bed reactor was 7-8°C, the hydrogenation efficiency of the hydrogenation solution was 6.0-6.4 g / L, and the hydrogenation selectivity was 89-92%. The apparatus was operated for 3200 hours, and a total of 340 tons of 27.5% hydrogen peroxide solution were obtained. During this time, 1.7 tons of activated alumina were replaced. A loss of catalyst activity was observed in the fixed-bed reactor, and the bed layer inlet temperature rose from 45°C at startup to 58°C.

[0176] As can be seen by comparing Examples 1-5 with Comparative Examples 1-5, when the method of this application is used to produce hydrogen peroxide, a hydrogenation efficiency of 10 g / L or more and a hydrogenation selectivity of over 98% can be obtained, the axial temperature difference of the reactor bed can be substantially eliminated, and as a result, the hydrogenation reaction selectivity, equipment efficiency and hydrogenation efficiency can be effectively improved, and the service life of the catalyst can be extended.

[0177] As can be seen by comparing Example 1 with Comparative Example 5, the hydrogen peroxide production method of this application has good economic and social benefits by effectively improving hydrogenation efficiency, significantly improving hydrogenation selectivity, extending the service life of the catalyst, increasing the production capacity of the apparatus by 110%, reducing the consumption of activated alumina per ton of product by 72%, and significantly reducing the amount of waste solid from the apparatus.

[0178] Although this application has described preferred embodiments in detail above, it is not limited to these embodiments. Within the scope of the technical concept of this application, various simple modifications can be made to the technical proposal of this application, and these simple modifications fall within the scope of protection of this application.

[0179] Furthermore, the various technical features described in the above embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, various possible combinations are not described in this application, but such combinations are also included within the scope of this application.

[0180] Furthermore, each embodiment of this application can be arbitrarily combined without departing from the spirit of this application, and embodiments combining these can be disclosed in this application.

Claims

1. A method for producing hydrogen peroxide, including the following steps: 1) A working solution containing alkylanthraquinone is supplied to a hydrogenation reactor, and the alkylanthraquinone is hydrogenated under conditions in which hydrogenation catalyst particles and hydrogen are present to obtain a slurry containing hydrogenated anthraquinone, by-products and hydrogenation catalyst particles, the hydrogenation catalyst particles are recovered from the slurry to obtain a circulating slurry rich in hydrogenation catalyst particles and a hydrogenation solution substantially free of hydrogenation catalyst particles, and the circulating slurry is returned to the hydrogenation reactor; 2) A step of dividing the hydrogenation solution into two streams, regenerating the first stream of hydrogenation solution to convert at least a portion of the by-products contained in the first stream of hydrogenation solution into alkylanthraquinone, thereby obtaining a regenerated hydrogenation solution; 3) A step of bringing the hydrogenation solution of the second flow and the regenerated hydrogenation solution into contact with an oxygen-containing gas to cause an oxidation reaction and obtain an oxidation solution containing hydrogen peroxide and alkylanthraquinone; and 4) A step of performing extraction and separation on the oxidizing solution to obtain an extract containing hydrogen peroxide and a raffinate containing alkylanthraquinone, and returning the raffinate to the hydrogenation reactor to be used as part of the working solution; Here, the ratio of the volumetric flow rate of the circulating slurry to the volumetric flow rate of the working solution is 6 to 20:1, preferably 8 to 18:1, and the ratio of the mass flow rate of the hydrogenation solution in the first flow to the mass flow rate of the hydrogenation solution in the second flow is 10 to 50:50 to 90, preferably 15 to 40:60 to 85.

2. The hydrogenation reaction in step 1) is carried out in a slurry bed reactor. Preferably, the conditions for the hydrogenation reaction include a pressure of 0.03 to 0.35 MPa, preferably 0.05 to 0.2 MPa; a temperature of 40 to 70°C, preferably 45 to 65°C; a ratio of the mass flow rate of the working solution to the mass flow rate of the hydrogenation catalyst, of 25 to 700:1, preferably 30 to 500:1; and a ratio of the standard volume flow rate of the hydrogen to the volume flow rate of the working solution, of 4 to 14:1, preferably 5 to 10:

1. Preferably, the hydrogenation reaction further generates a hydrogen-containing tail gas, and step 1) further comprises discharging the hydrogen-containing tail gas and / or compressing the hydrogen-containing tail gas and then returning it to the hydrogenation reactor, the method according to claim 1.

3. Step 1) further includes performing a first cooling on the circulating slurry to obtain a first cooling solution, and returning the first cooling solution to the hydrogenation reactor, Preferably, the temperature of the first cooling solution is 40 to 70°C, and more preferably 45 to 65°C, according to claim 1 or 2.

4. The regeneration in step 2) is carried out in a regenerating reactor, which is selected from a fixed-bed reactor, a slurry-bed reactor, or a combination thereof. Preferably, when the regeneration reactor is a fixed-bed reactor, the regeneration catalyst is modified alumina, and more preferably, the modified alumina is alumina modified with at least one metal selected from alkali metals, alkaline earth metals, and rare earth metals. Preferably, the regeneration reactor is a slurry bed reactor, and the regeneration catalyst is a modified molecular sieve, and more preferably, the modified molecular sieve is a molecular sieve modified with at least one metal selected from alkali metals, alkaline earth metals, and rare earth metals, according to any one of claims 1 to 3.

5. Step 3) further includes, before the oxidation reaction, mixing the second stream of the hydrogenation solution with the regenerated hydrogenation solution to obtain a mixed solution, performing a second cooling on the mixed solution to obtain a second cooled solution, Preferably, the method according to any one of claims 1 to 4, wherein step 3) further comprises mixing the second cooling solution with the first pH adjusting agent to obtain an adjusted solution before the oxidation reaction, and then optionally filtering the adjusted solution.

6. The extractant used in step 4) comprises water and a selectable second pH adjuster. Preferably, the method according to any one of claims 1 to 5, wherein step 4) further comprises performing a third cooling on the oxidizing solution before the extraction to obtain a third cooled solution.

7. Step 4) further includes vacuum drying the raffinate at a mass flow rate of at least 10% to obtain a residual liquid, and returning the residual liquid and the remaining raffinate together to the hydrogenation reactor. Preferably, the raffinate is vacuum-dried at a mass flow rate of at least 30%, Preferably, the method according to any one of claims 1 to 6, wherein the vacuum drying further generates water and / or organic matter, and step 4) further comprises circulating the water and / or organic matter.

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