Continuous production process of o-hydroquinone and hydroquinone

Abstract

The invention provides a continuous production process of o-hydroquinone and hydroquinone, and relates to the technical field of chemical synthesis. According to the invention, phenol and hydrogen peroxide are used as raw materials, and high-purity catechol and hydroquinone products are continuously produced through a reaction process, a filtration process, a hydrogen peroxide decomposition process, an extraction process and a refining process. The filtering procedure, the extracting procedure, the extracting agent recycling procedure, the primary phenol recycling procedure, the tar removing procedure, the secondary phenol recycling procedure, the catechol refining procedure and the hydroquinone refining procedure which are connected in sequence are arranged to separate and purify materials after reaction, the whole technological process is short, and the yield is high; the extraction process is adopted to replace the dehydration rectification operation in the traditional process to remove the phenol-containing wastewater, so that the phenol recovery rate is increased, and the subsequent wastewater treatment burden is reduced; the tar removal operation is performed before the secondary phenol recovery operation, so that the retention time of tar impurities in the whole process system is shortened, the process safety is improved, and the subsequent operation risk is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of chemical synthesis, and in particular to a continuous production process of o- and hydroquinone. Background Art

[0002] Catechol and hydroquinone are important raw materials for fine chemicals and pharmaceutical intermediates, and their downstream products involve many industries such as food, cosmetics, pesticides, medicines, dyes, polymer materials, etc. With the continuous expansion of the downstream application fields of the two types of catechols and the continuous development of the derivative product market, the global demand for catechol and hydroquinone has shown a trend of sustained growth.

[0003] At present, the preparation method of hydroquinone is mainly the phenol peroxide hydroxylation method, which uses phenol and hydrogen peroxide as raw materials, and generates catechol and hydroquinone at the same time under the action of a catalyst. In the existing production process, high-concentration hydrogen peroxide is often used as a raw material, which has the risk of explosion. At the same time, in order to avoid the generation of a large amount of heavy components (tar) during the reaction process, the conversion rate of phenol is controlled very low, and the operating cost is high; in addition, there are problems such as high energy consumption and difficulty in removing tar in the subsequent separation and purification process of the product.

[0004] The separation of the mixed product after the phenol peroxide hydroxylation reaction is also a problem that restricts the industrial production of catechol and hydroquinone. The more typical separation and purification technologies for phenol, o- and hydroquinone aqueous solutions are the French Rhone-Poulenc method and the German Bayer method. The separation method of the Rhone-Poulenc company is to use a dehydration distillation tower to remove phenol-containing wastewater, a dephenol distillation tower to remove phenol once, a decoking distillation tower and an evaporator to remove tar, a secondary dephenol tower to remove phenol, and a product distillation tower to separate catechol and hydroquinone; the wastewater discharged from the top of the tower in this separation method contains a relatively high phenol content (about 10%), which increases the difficulty of subsequent wastewater treatment. The separation process of Bayer AG in Germany is that the distillation tower removes water and organic solvent, the dephenolization distillation tower removes phenol, the catechol distillation tower is removed, and the evaporator separates hydroquinone and tar; the method places the removal of tar in the last step, so that the tar stays in a high temperature environment for a long time, the viscosity continues to increase, the fluidity is poor, and carbonization or expansion occurs easily. Its existence will also aggravate the thermal sensitivity of o- and hydroquinone, and there are great difficulties in material transportation and separation, and the energy consumption of the system will also be increased. The domestic similar separation and purification technology has patent CN200610072928.6, and its main steps are that the raw material liquid passes through the dehydration distillation tower, the first dephenolization distillation tower, the second dephenolization distillation tower, the decoking distillation tower and the deep steaming kettle, and the product distillation tower in sequence. This method places the decoking distillation tower behind the second dephenolization tower, which also increases the difficulty of tar transportation. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention discloses a continuous production process for o- and hydroquinone, which can effectively recover the raw material phenol to reduce the burden of subsequent wastewater treatment, and reduce the residence time of tar in the process to improve the safety of process operation, and continuously output high-quality hydroquinone and o- and o-catechol products.

[0006] In order to achieve the above technical objectives, the present invention provides a continuous production process of o-hydroquinone and hydroquinone, which includes a reaction process, a filtering process, a hydrogen peroxide decomposition process, an extraction process and a refining process, wherein the reaction process: phenol and hydrogen peroxide undergo a hydroxylation reaction under the action of a catalyst to obtain a reacted material; the filtering process: the reacted material is filtered to separate the solid-phase catalyst to obtain a filtered clear liquid; the hydrogen peroxide decomposition process: sodium sulfite solution is added to the filtered clear liquid to decompose the hydrogen peroxide contained therein to obtain a material to be extracted; the extraction process: the material to be extracted is input into an extraction tower, an oil phase is extracted from the top of the tower, and the oil phase is input into the refining process; a water phase is extracted from the bottom of the extraction tower;

[0007] The refining process comprises the following steps: S1, the oil phase output from the extraction process is input into an extractant recovery tower; the top extract of the extractant recovery tower is subjected to phase separation treatment by a first phase separation device to obtain an extractant, and the bottom extract is input into a first dephenolization tower; S2, the top extract of the first dephenolization tower is subjected to phase separation treatment by a second phase separation device to obtain phenol, and the bottom extract is input into a detarring tower; S3, the top extract of the detarring tower is input into a second dephenolization tower, and materials containing tar are extracted from the bottom of the tower; S4, phenol is extracted from the top of the second dephenolization tower, and the bottom extract is input into a catechol tower; S5, catechol is extracted from the top of the catechol tower, and the bottom extract is input into a light-removing tower; S6, light component impurities are extracted from the top of the light-removing tower, and the bottom material is input into a hydroquinone tower; S7, hydroquinone is extracted from the top of the hydroquinone tower, and heavy component impurities are extracted from the bottom of the tower.

[0008] In the above technical solution, the raw material phenol is preheated and then fed into the reaction process with hydrogen peroxide, and a hydroxylation reaction occurs under the action of a catalyst to obtain a reacted material containing catechol, hydroquinone, hydrogen peroxide, water, a catalyst, tar, quinone and phenol. The reacted material is fed into the filtering process.

[0009] In the filtering step, the reacted material is filtered to separate the solid phase catalyst, and this part of the catalyst can be directly returned to the reaction step for recycling; the obtained filtered clear liquid enters the hydrogen peroxide decomposition step to decompose the unreacted hydrogen peroxide.

[0010] In the hydrogen peroxide decomposition step, a sodium sulfite solution in excess relative to the hydrogen peroxide content is added to the filtered clear liquid, and the hydrogen peroxide in the filtrate is eliminated through an oxidation reaction to obtain a material to be extracted; the obtained material to be extracted includes components such as catechol, hydroquinone, sodium sulfate, water, a catalyst, tar and phenol; this part of the material to be extracted enters the extraction step.

[0011] In the extraction process, after the material to be extracted is extracted by the extractant, an oil phase containing o-hydroquinone, phenol, water, tar, extractant and other components is extracted from the top of the extraction tower, and this part of the oil phase is input into the refining process; an aqueous phase containing a small amount of sodium sulfate, a small amount of extractant and water is extracted from the bottom of the extraction tower. The present invention adopts an extraction process to replace the dehydration distillation tower in the traditional process to remove phenol-containing wastewater from the material after the reaction, which not only reduces the overall process energy consumption, but also greatly reduces the phenol content in the wastewater, thereby reducing the burden of subsequent wastewater treatment.

[0012] The refining process comprises the following steps:

[0013] In step S1, the oil phase containing the extractant output from the extraction process is input into the extractant recovery tower; the top product of the extractant recovery tower is subjected to phase separation treatment by a first phase separation device to obtain the extractant, which can be returned to the extraction process for recycling, and the aqueous phase containing a small amount of extractant obtained by phase separation is returned to the top of the extraction recovery tower as reflux; the bottom product of the extractant recovery tower is input into a dephenolization tower.

[0014] In step S2, a mixture of phenol and water is extracted from the top of the dephenolization tower, and this part of the material enters a phenol phase separation tank after cooling. A part of the oil phase such as phenol obtained by phase separation is returned to the tower as reflux, and a part is returned to the phenol raw material tank or directly returned to the reaction process; the water phase obtained by phase separation enters a reaction process water tank for recycling; the material extracted from the bottom of the dephenolization tower enters a detarring tower.

[0015] In step S3, the tar-containing materials extracted from the bottom of the detarring tower enter the tar post-processing process, and the materials extracted from the top of the detarring tower enter the second dephenolizing tower. The present invention sets a detarring process before the secondary phenol recovery, thereby effectively reducing the residence time of tar impurities in the process system and reducing the risk of subsequent operations.

[0016] In step S4, phenol is extracted from the top of the second dephenolization tower, and the part of phenol is returned to the phenol raw material tank; the material extracted from the bottom of the second dephenolization tower enters the catechol tower. The present invention fully recovers phenol in the material after the reaction through step S2 combined with step S4, thereby improving the utilization rate of raw materials and reducing the process cost, which will bring significant economic benefits in large-scale production.

[0017] In step S5, catechol with a mass fraction greater than 99.8% is extracted from the top of the catechol tower, and the extracted material from the bottom of the tower is input into a light component removal tower to further remove light component impurities contained therein.

[0018] In step S6, light component impurities are taken out from the top of the light removal tower, and the materials in the bottom of the tower are input into the hydroquinone tower.

[0019] In step S7, hydroquinone with a mass fraction greater than 99.8% is taken from the top of the hydroquinone tower, and heavy impurities are taken from the bottom of the tower.

[0020] Compared with the prior art, the invention has the following beneficial effects: the invention uses phenol and hydrogen peroxide as raw materials, and continuously produces high-purity catechol and hydroquinone products through a reaction process, a filtering process, a hydrogen peroxide decomposition process, an extraction process and a refining process; by setting sequentially connected filtering processes, extraction processes, extractant recovery, primary phenol recovery, detarring, secondary phenol recovery, catechol refining and hydroquinone refining processes to separate and purify the materials after the reaction, the overall process flow is short and the yield is high; the invention adopts an extraction process to replace the dehydration and distillation operation in the traditional process to remove phenol-containing wastewater, thereby improving the phenol recovery rate and reducing the burden of subsequent wastewater treatment; the detarring operation is placed before the secondary phenol recovery operation, thereby reducing the residence time of tar impurities in the overall process system, improving the process safety and reducing the subsequent operation risk. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0022] Figure 1 A structural diagram showing a continuous production process of o-hydroquinone and o-hydroquinone according to the present invention;

[0023] Figure 2 Another structural diagram of the continuous production process of o- and hydroquinone according to the present invention is shown.

[0024] The above drawings include the following reference numerals:

[0025] 1-reactor, 2-filter, 3-hydrogen peroxide decomposition reactor, 4-extraction tower, 51-extraction agent recovery tower, 52-phenol removal tower 1, 53-tar removal tower, 54-phenol removal tower 2, 55-catechol tower, 56-light removal tower, 57-hydroquinone tower, 6-stripping tower, 71-first phase separation device, 72-second phase separation device, S1-phenol input pipe, S2-hydrogen peroxide input pipe, S3-catalyst slurry input pipe, S4-catalyst recycling pipeline, S5-sodium sulfite input pipe, S6-extraction agent input pipe, S7-extraction agent recycling pipe, S8-water phase circulation pipe, S9-first benzene Phenol delivery pipe, S10-tar delivery pipe, S11-second phenol delivery pipe, S12-catechol delivery pipe, S13-light component impurity delivery pipe, S14-hydroquinone delivery pipe, S15-wastewater output pipe, 81-first gas-liquid separation tank, 82-first steam compressor, 83-first steam buffer tank, 84-second steam compressor, 85-second steam buffer tank, 86-third steam compressor, 87-third steam buffer tank, 88-steam generator, 89-second gas-liquid separation tank, 91-secondary steam A, 92-recompression steam, 93-tertiary compression steam, 94-secondary steam B. DETAILED DESCRIPTION

[0026] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below, and preferred embodiments of the present invention are given. However, it should be understood that these embodiments are only used for more detailed description and should not be understood as limiting the present invention in any form, i.e., not intended to limit the scope of protection of the present invention.

[0027] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The test reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods, unless otherwise specified, are all conventional methods.

[0028] In addition, the terms "first", "second" and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first", "second" and "third" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0029] The present invention provides a continuous production process of o-hydroquinone, which includes a reaction process, a filtering process, a hydrogen peroxide decomposition process, an extraction process and a refining process. Figure 1 An optional structural diagram of this embodiment is shown, wherein:

[0030] Reaction process: the phenol input pipe S1, the hydrogen peroxide input pipe S2 and the catalyst slurry input pipe S3 are respectively connected to the reactor 1, and the raw material phenol reacts with hydrogen peroxide to undergo a hydroxylation reaction in the reactor 1 to obtain a reacted material including catechol, hydroquinone, hydrogen peroxide, water, catalyst, tar, quinone and phenol.

[0031] Filtration process: the reacted material is input into the filter 2, and the solid catalyst is separated by filtration. This part of the catalyst is recycled through the catalyst recycling pipeline S4; the obtained filtered clear liquid is input into the hydrogen peroxide decomposition process.

[0032] Hydrogen peroxide decomposition step: The filtered clear liquid is input into the hydrogen peroxide decomposition reactor 3, and reacts with the sodium sulfite input from the sodium nicotinate input pipe to decompose the unreacted hydrogen peroxide to obtain the material to be extracted containing catechol, hydroquinone, sodium sulfate, water, catalyst, tar and phenol.

[0033] Extraction process: The extraction process is carried out in the extraction tower 4, and the lower part of the extraction tower 4 is connected to the extractant input pipe S6; the material to be extracted is input into the extraction tower 4, and the oil phase containing o-hydroquinone, phenol, tar and isopropyl ether is extracted from the top of the tower, and this part of the oil phase is input into the subsequent refining process; the water phase containing sodium sulfate, water, isopropyl ether and other organic matter is extracted from the bottom of the extraction tower 4;

[0034] Refining process: including the following steps,

[0035] Step (S1), the oil phase output from the extraction process is input into the extractant recovery tower 51; a mixture of extractant and water is extracted from the top of the extractant recovery tower 51, and the mixture is input into the first phase separation device 71 for phase separation treatment to obtain an extractant, and the extractant is recycled through the extractant recycling pipe S7; the obtained water phase is returned to the extractant recovery tower 51 as reflux; the extract from the bottom of the extractant recovery tower 51 contains o-hydroquinone, phenol, tar and other components, which are input into the dephenolization tower 52.

[0036] Step (S2), the top of the dephenolization tower 52 containing phenol and water is input into the second phase separation device 72, and phenol is obtained after phase separation treatment. A part of the phenol is returned to the dephenolization tower 52 as reflux, and a part is input into the phenol raw material tank through the first phenol delivery pipe S9 for recycling; the water phase obtained by phase separation is input into the reaction process water tank through the water phase circulation pipe S8 for recycling; the tower bottom output is input into the detarring tower 53.

[0037] In step (S3), the overhead product of the detarring tower 53 is input into the second dephenolizing tower 54, and the material containing tar is extracted from the bottom of the tower. This part of the material is input into the subsequent tar treatment process through the tar conveying pipe S10.

[0038] In step (S4), the phenol extracted from the top of the second phenol removal tower 54 is fed into the phenol raw material tank through the second phenol delivery pipe S11 for recycling; and the extracted material from the bottom of the tower is fed into the catechol tower 55.

[0039] Step (S5), high-purity catechol is extracted from the top of the catechol tower 55, and this part of the material is input into the subsequent product packaging process through the catechol conveying pipe S12; the extracted material from the bottom of the catechol tower 55 is input into the light removal tower 56.

[0040] Step (S6), light component impurities are extracted from the top of the light component removal tower 56, and these impurities are input into the subsequent impurity treatment process through the light component impurity conveying pipe S13; the materials extracted from the bottom of the light component removal tower 56 are input into the hydroquinone tower 57.

[0041] Step (S7), high-purity hydroquinone is extracted from the top of the hydroquinone tower 57, and this part of the material is input into the subsequent product packaging process through the hydroquinone delivery pipe S14; the heavy component impurities are extracted from the bottom of the hydroquinone tower 57.

[0042] In a further example of the present invention, light component impurities are output from the side sampling port of the second dephenolization tower 54, thereby improving the distillation efficiency and being beneficial to improving the product purity of phenol removed by the second dephenolization tower 54 and o- and hydroquinone subsequently separated and purified; preferably, the light component impurities output from the side sampling port of the second dephenolization tower 54 and the light component impurities extracted from the top of the light component removal tower 56 are input into the subsequent impurity treatment process, and the process treatment efficiency is improved by combining the light component impurities for treatment.

[0043] In a further example of the present invention, the heavy impurities extracted from the bottom of the hydroquinone tower 57 are input into the detarring tower 53, and then the material containing tar is extracted from the tar conveying pipe S10 of the detarring tower 53 and sent to the subsequent tar treatment process for post-treatment, which is beneficial to further recover the target product in the extract from the bottom of the hydroquinone tower and improve the process yield.

[0044] In a further example of the present invention, the concentration of hydrogen peroxide may be selected to be no more than 30%, which is much lower than the 60% concentration of hydrogen peroxide in the existing process, greatly reducing the risk factor of the reaction and subsequent process operations; in an optional example of the present invention, the concentration of hydrogen peroxide is preferably 15%-30%.

[0045] In a further example of the present invention, the mass ratio of phenol to hydrogen peroxide can be selected to be 1:(0.2-0.4). The optimization of the relative amounts of the raw materials phenol and hydrogen peroxide is beneficial to improving the utilization rate of hydrogen peroxide and improving process safety.

[0046] It should be noted that the present invention is not limited to the specific components of the catalyst, and those skilled in the art can select a suitable solid catalyst as needed, such as an oxide composite catalyst containing Si, B, Al, Ti, O, and N elements. After the catalyst and water are configured into a slurry, it enters the reactor together with the raw material phenol. In a further example of the present invention, the mass ratio of the phenol to the catalyst can be selected to be 1: (0.01-0.1).

[0047] In a further example of the present invention, the extractant may optionally include at least one of di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, diisopropyl ether, di-n-propyl ether, diamyl ether, methyl isobutyl ketone, 2-pentanone, and 3-pentanone, preferably di-n-butyl ether or diisopropyl ether.

[0048] In a further example of the present invention, the control conditions of the reaction process, the extraction process and the refining process are explored and optimized. Specifically:

[0049] Operating parameters of reactor 1:

[0050] name Parameter range Operating temperature ℃ 60-90 Operating pressure kPaA 100-300

[0051] Operating parameters of extraction column 4:

[0052] name Parameter range Tower top operating temperature ℃ 20-60 Bottom operating temperature ℃ 20-60 Operating pressure kPaA 100-300

[0053] The operating parameters of the extractant recovery tower 51 are:

[0054] name Parameter range Tower top operating temperature ℃ 50-150 Tower bottom operating temperature ℃ 100-150 Operating pressure kPaA 100-300

[0055] The operating parameters of the first phenol removal tower 52 are:

[0056] name Parameter range Tower top operating temperature ℃ 50-150 Bottom operating temperature ℃ 190-220 Operating pressure kPaA 10-200

[0057] Operating parameters of the detarring tower 53:

[0058] name Parameter range Tower top operating temperature ℃ 50-150 Tower bottom operating temperature ℃ 200-300 Operating pressure kPaA 1-50

[0059] The operating parameters of the second phenol removal tower 54 are:

[0060] name Parameter range Tower top operating temperature ℃ 50-150 Tower bottom operating temperature ℃ 100-300 Operating pressure kPaA 1-20

[0061] The operating parameters of catechol tower 55 are:

[0062] name Parameter range Tower top operating temperature ℃ 150-180 Tower bottom operating temperature ℃ 200-230 Operating pressure kPaA 1-15

[0063] The operating parameters of the lightness removal tower 56 are:

[0064] name Parameter range Tower top operating temperature ℃ 170-200 Bottom operating temperature ℃ 180-230 Operating pressure kPaA 1-15

[0065] The operating parameters of the hydroquinone column 57 are:

[0066] name Parameter range Tower top operating temperature ℃ 170-200 Tower bottom operating temperature ℃ 180-230 Operating pressure kPaA 1-15

[0067] In a further example of the present invention, a wastewater treatment process is also included: the water phase extracted from the bottom of the extraction tower 4 is input into the stripping tower 6, which is conducive to recovering the extract and target product in the bottom of the extraction tower, and improving the process yield; the top of the stripping tower 6 is input into the first phase separation device 71, and the extractant is recovered by phase separation, and the water phase obtained by phase separation is returned to the stripping tower 6 as reflux; the bottom of the stripping tower 6 outputs wastewater through the wastewater output pipe S15. Optionally, the wastewater output from the stripping tower 6 is further treated by Fenton treatment and then enters the subsequent wastewater treatment process.

[0068] The operating conditions of stripping tower 6 were further explored and optimized:

[0069] Operating parameters of stripping tower 6:

[0070] name Parameter range Tower top operating temperature ℃ 100-150 Tower bottom operating temperature ℃ 100-150 Operating pressure kPaA 100～300

[0071] In a further example of the present invention, a tail gas treatment process is further included, wherein the primary tail gas generated in the reaction process, the filtration process, and the hydrogen peroxide decomposition process is subjected to multi-stage water washing to obtain secondary tail gas, which is discharged after being adsorbed by activated carbon, and the obtained washing liquid is recycled. Optionally, the tail gas generated in the wastewater treatment process is input into the tail gas treatment process for treatment.

[0072] In a further example of the present invention, a catalyst regeneration process is also included: the solid phase catalyst separated in the filtering process is dried and roasted to activate the catalyst. In the actual process, after analysis and detection, if the catalyst separated in the filtering process meets the reuse requirements, it can be directly returned to the reaction process for recycling; when the activity of the catalyst separated by filtering decreases and needs to be regenerated, the separated and recovered catalyst is input into the catalyst regeneration process, and the regenerated catalyst is activated by drying and roasting; the activated catalyst is returned to the reaction process together with the newly added catalyst for recycling.

[0073] In a further example of the present invention, a product packaging process is also included to output the catechol product and the hydroquinone product by tableting and packaging.

[0074] Example 1

[0075] Based on the above technical solution, this embodiment proposes a continuous production process for o- and hydroquinone that includes waste heat recovery technology features, which uses waste heat recovery combined with mechanical steam recompression energy-saving technology to effectively reduce the overall process energy consumption. Figure 2 Another structure of the continuous production process of o-hydroquinone and o-hydroquinone of the present invention is shown, specifically:

[0076] The overhead products of the first dephenolization tower 52, the detarring tower 53 and the second dephenolization tower 54 are heat exchanged with water to obtain a gas-liquid mixture, and the gas-liquid mixture is separated into gas and liquid by the first gas-liquid separation tank 81 and compressed by the first steam compressor 82 to obtain secondary steam A91; further, the secondary steam A91 is 300-600 kPaA steam; further, the secondary steam A91 is used for preheating raw materials, heating the hydrogen peroxide decomposition process, heating the reboiler of the extractant recovery tower 51 and heating the equipment and pipelines in step S1.

[0077] In the actual process, the water used for heat exchange with the top extracts of the first dephenol tower 52, the detarring tower 53 and the second dephenol tower 54 can come from the saturated water separated by the gas-liquid separation tank, which produces a gas-liquid mixture with a relatively low pressure of 20 to 80 kPaA after heat exchange; this part of the gas-liquid mixture is separated by gas-liquid separation in the first gas-liquid separation tank 81 to obtain steam of 20 to 80 kPaA, and is further compressed by the first steam compressor 82 to obtain secondary steam A91.

[0078] In specific processes, such as Figure 2 As shown, the secondary steam A91 can be input into the first steam buffer tank 83, and used for preheating of raw materials, heating of the hydrogen peroxide decomposition process, heating of the reboiler of the extractant recovery tower 51, and heating of the equipment and pipelines in step S1. The liquid phase obtained after the condensation of the secondary steam A91 is input into the first gas-liquid separation tank 81, and driven by the circulating pump, it exchanges heat with the top extracts of the dephenolization tower 1 52, the detarring tower 53 and the dephenolization tower 2 54 to produce a gas-liquid mixture, thereby recycling and utilizing the waste heat.

[0079] Furthermore, the secondary steam A91 is compressed by the second steam compressor 84 to obtain recompressed steam 92, and the recompressed steam 92 is used for heating the equipment and pipelines in steps S2 to S7; preferably, the recompressed steam 92 is 1000-1500 kPaA steam.

[0080] Optionally, the secondary steam A91 can be used to heat the reboiler of the stripping tower 6; the steam after heat exchange is compressed by the second steam compressor to obtain recompressed steam 92.

[0081] like Figure 2 As shown, the steam in the first steam buffer tank 83 can be input into the second steam buffer tank 85 after being compressed by the second steam compressor 84, and the part of the recompressed steam 92 can be used for heating the equipment pipelines of the detarring tower 53, the second dephenolizing tower 54, the catechol tower 55, the lightness removal tower 56, and the hydroquinone tower 57, or for heating the equipment pipelines of subsequent tar processing processes, product packaging processes, etc.

[0082] Further, the recompressed steam 92 is passed through the third steam compressor 86 to obtain the tertiary compressed steam 93. Optionally, the tertiary compressed steam 93 is 3500-4200 kPaA; optionally, the tertiary compressed steam 93 is used for heating the reboiler of the dephenolization tower 52. Figure 2 As shown, the tertiary compressed steam 93 is input into the third steam buffer tank 87, and this part of the tertiary compressed steam 93 can be used for heating the reboiler of the first phenol removal tower 52, or other processes requiring high-pressure steam. Optionally, the steam obtained after the heat exchange of the tertiary compressed steam 93 is input into the first steam buffer tank 83, so as to achieve more sufficient waste heat recovery and utilization.

[0083] Example 2

[0084] This embodiment shows a continuous production process of o- and hydroquinone that includes more waste heat recovery technical features, further recovers process waste heat, and reduces process energy consumption. Figure 2 As shown, specifically:

[0085] The overhead extracts of the light-removal tower 56 and the hydroquinone tower 57 are heat-exchanged with the heat-conducting oil, and the heat-conducting oil after the heat exchange generates a gas-liquid mixture in the steam generator 88, and the gas-liquid mixture is subjected to gas-liquid separation in the second gas-liquid separation tank 89 to obtain secondary steam B94, thereby realizing the recovery and utilization of the overhead waste heat of the light-removal tower 56 and the hydroquinone tower 57. Preferably, the secondary steam B94 is 300-600 kPaA steam. Preferably, the secondary steam B94 is used for preheating raw materials, heating the hydrogen peroxide decomposition process, heating the reboiler of the extractant recovery tower 51, and heating the equipment and pipelines of step S1.

[0086] In a specific process, the secondary steam B94 produced can be input into the first steam buffer tank 83 and input into other processes. In an optional example of the embodiment, the secondary steam B94 is input into other processes after merging with the secondary steam A91.

[0087] Furthermore, the liquid phase in the second gas-liquid separation tank 89 is heat-exchanged with the steam generator 88 and the top extraction of the catechol tower 55 respectively, and then input into branch one, through the steam generator 88 to generate a gas-liquid mixture and return to the second gas-liquid separation tank 89, and obtains secondary steam B94 through gas-liquid separation, and the obtained liquid phase goes to the steam generator 88; and / or, branch two, after heat exchange with the top extraction of the catechol tower 55 to generate a gas-liquid mixture, returns to the second gas-liquid separation tank 89, obtains secondary steam B94 through gas-liquid separation, and the obtained liquid phase is heat-exchanged with the top extraction of the catechol tower 55; thus, it is recycled through branch one and branch two.

[0088] Example 3

[0089] This embodiment shows the process of continuous production of o- and hydroquinone under the specific working conditions of the present invention. It should be noted that this embodiment is only a preferred display and does not limit the scope of protection of the present invention.

[0090] A continuous production process of o-hydroquinone and o-hydroquinone, specifically:

[0091] Reaction process: raw materials phenol and 27.5% hydrogen peroxide and catalyst slurry, temperature 75°C, flow rate 25000kg / h, hydroxylation reaction occurs in reactor 1, wherein the mass ratio of phenol, hydrogen peroxide and catalyst is 1:0.33:0.025, the mass ratio of catalyst to process water in the catalyst slurry is 0.02:1, and the reaction material containing catechol, hydroquinone, water, catalyst and tar, unreacted hydrogen peroxide and phenol is generated. The conversion rate of phenol is 15%, the yield of o- / hydroquinone is 10.2%, the ratio of o- / hydroquinone in the reaction material is 0.77, and the proportion of tar is less than 0.74%.

[0092] The raw material phenol preheating equipment and pipeline are heated by 400 kPaA secondary steam A91 input from the first steam buffer tank 83. The operating parameters of the reactor 1 are:

[0093] name Operation parameters Operating temperature ℃ 85 Operating pressure kPaA 150

[0094] Filtration process: the material after the reaction enters the filtration process, and the catalyst separated by filtration through the filter 2 is directly returned to the reaction process. If the analysis sampling is unqualified, it will go to the catalyst regeneration and activation process, and the regenerated and activated catalyst will return to the reaction process; the filtered clear liquid enters the hydrogen peroxide decomposition reactor 3.

[0095] Hydrogen peroxide decomposition process: the filtered clear liquid is input into the hydrogen peroxide decomposition reactor 3, and a 10% sodium sulfite solution is input into the reactor through the sodium sulfite input pipe S5. The unreacted hydrogen peroxide in the filtered clear liquid is reduced and decomposed into water and oxygen. The oxygen enters the tail gas treatment process, and the obtained material to be extracted enters the extraction tower 4.

[0096] Extraction process: the material to be extracted enters the middle and upper feed port of the extraction tower 4, and the extractant diisopropyl ether enters from the extractant inlet pipe S6 connected to the bottom of the extraction tower 4. The oil phase containing catechol, hydroquinone, diisopropyl ether, etc. extracted from the top of the extraction tower 4 enters the extractant recovery tower 51; the aqueous phase containing water, a small amount of diisopropyl ether and sodium sulfate, etc., extracted from the bottom of the extraction tower 4 enters the stripping tower 6.

[0097] The operating parameters of the extraction tower 4 are:

[0098] name Operation parameters Tower top operating temperature ℃ 39.2 Tower bottom operating temperature ℃ 44.3 Operating pressure kPaA 150

[0099] The operating parameters of the stripping tower 6 are:

[0100] name Operation parameters Tower top operating temperature ℃ 135.2 Tower bottom operating temperature ℃ 136.8 Operating pressure kPaA 210

[0101] Refining process: the oil phase output from the extraction process is input into the extractant recovery tower 51; the top product of the extractant recovery tower 51 is subjected to phase separation treatment by the first phase separation device 71 to obtain the extractant, and the product from the bottom of the tower is input into the first phenol removal tower 52.

[0102] The operating parameters of the extractant recovery tower 51 are:

[0103] name Operation parameters Tower top operating temperature ℃ 112.3 Tower bottom operating temperature ℃ 145.2 Operating pressure kPaA 230 Reflux ratio 0.3 Theoretical plates 15 Feeding position 5

[0104] The top gas phase of the dephenolization tower 52 exchanges heat with the saturated water from the first steam buffer tank 83 and condenses to produce a gas-liquid mixture, which then passes through the first gas-liquid separation tank 81 to obtain 50kPaA steam. The condensate of the top gas phase is returned to the dephenolization tower 52 as the top reflux, and the rest is extracted and input into the phenol raw material tank or directly reacted in the process for phenol recycling; the material extracted from the bottom of the dephenolization tower 52 enters the decoking tower, the bottom reboiler of the de-extraction tower 4 is heated by 400kPaA steam, and the tank equipment and pipelines containing phenol are heated by 400kPaA steam.

[0105] The operating parameters of the first phenol removal tower 52 are:

[0106]

[0107]

[0108] The top gas of the detarring tower 53 exchanges heat with the saturated water from the first gas-liquid separation tank 81 and condenses to produce a gas-liquid mixture, which is then separated by the first gas-liquid separation tank 81 to obtain 50kPaA steam; the material produced from the top of the tower enters the second dephenolization tower 54, and the tank equipment and pipelines containing phenol are heated by 400kPaA steam; the tar produced from the bottom of the detarring tower 53 is input into the subsequent tar treatment process through the tar conveying pipe S10, and the conveying pipeline can optionally use 1200kPaA steam generated by the second steam buffer tank 85 for heating.

[0109] Operating parameters of the detarring tower 53:

[0110] name Operation parameters Tower top operating temperature ℃ 123.2 Bottom operating temperature ℃ 255.3 Operating pressure kPaA 10 Reflux ratio 0.8 Theoretical plates 15 Feeding position 8

[0111] The top gas phase of the second dephenolization tower 54 exchanges heat with the saturated water from the first gas-liquid separation tank 81 and condenses to produce a gas-liquid mixture, which is then separated by the first gas-liquid separation tank 81 to obtain 50kPaA steam; the material produced from the top of the tower is input into the phenol raw material tank or directly returned to the reaction process; the material produced from the bottom of the tower enters the catechol tower 55, and the tank equipment and pipelines are heated by 400kPaA steam.

[0112] The operating parameters of the second phenol removal tower 54 are:

[0113] name Operation parameters Tower top operating temperature ℃ 117.9 Tower bottom operating temperature ℃ 204.0 Operating pressure kPaA 10 Reflux ratio 3 Theoretical plates 45 Feeding position 30 Side Picking 12

[0114] The top gas phase of the catechol tower 55 exchanges heat with the saturated water from the second gas-liquid separation tank 89 and condenses to produce a gas-liquid mixture, which is then separated in the second gas-liquid separation tank 89 to obtain 400 kPaA steam; the mass fraction of the catechol product extracted from the top of the tower is greater than 99.8%, and the yield is greater than 98%. The material extracted from the bottom of the tower enters the light removal tower 56.

[0115] The operating parameters of catechol tower 55 are:

[0116] name Operation parameters Tower top operating temperature ℃ 162.3 Bottom operating temperature ℃ 206.8 Operating pressure kPaA 8 Reflux ratio 3 Theoretical plates 16 Feeding position 8

[0117] The gas phase at the top of the light-removal tower 56 is condensed by the heat transfer oil heat exchanger, and the light component impurities produced from the top of the tower enter the impurity tank; the produced material from the bottom of the tower enters the hydroquinone tower 57. The operating parameters of the light-removal tower 56 are:

[0118] name Operation parameters Tower top operating temperature ℃ 192.3 Tower bottom operating temperature ℃ 203.6 Operating pressure kPaA 6.1 Reflux ratio 3.9 Theoretical plates 51 Feeding position 16

[0119] The gas phase at the top of the hydroquinone tower 57 is condensed by a heat transfer oil heat exchanger. The mass fraction of the hydroquinone product produced from the top of the tower is greater than 99.8%, and the yield is greater than 95%. The bottom of the tower is returned to the detarring tower 53, where the equipment and pipelines are heated by 1200kPaA steam. The operating parameters of the hydroquinone tower 57 are:

[0120] name Operation parameters Tower top operating temperature ℃ 191.8 Bottom operating temperature ℃ 200.6 Operating pressure kPaA 5.6 Reflux ratio 3 Theoretical plates 35 Feeding position 20

[0121] The heat transfer oil after heat exchange with the top of the light removal tower 56 and the hydroquinone tower 57 is heat exchanged with saturated water from the second gas-liquid separation tank 89, and the heat is recovered to obtain a 400 kPa gas-liquid mixed liquid that returns to the second gas-liquid separation tank 89.

[0122] The catechol and hydroquinone obtained from the catechol tower 55 and the hydroquinone tower 57 enter the product tableting and packaging process to obtain the final product. The equipment and pipelines in the product tableting and packaging processes are heated by steam of 1200 kPaA.

[0123] In this embodiment, the catechol tower 55 saves 0.524 Gcal / h of energy, the lightness removal tower 56 saves 1.524 Gcal / h of energy, and the hydroquinone tower 57 saves 0.787 Gcal / h of energy.

[0124] It should be noted that the above contents are further detailed descriptions of the present invention in combination with specific implementation methods, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple improvements can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A continuous production process of o-hydroquinone, characterized in that: The method comprises a reaction step, a filtration step, a hydrogen peroxide decomposition step, an extraction step and a purification step, wherein: The reaction process comprises: phenol and hydrogen peroxide undergo hydroxylation reaction under the action of a catalyst to obtain a reacted material; The filtering step: the reacted material is filtered to separate the solid phase catalyst and obtain a filtered clear liquid; The hydrogen peroxide decomposition step: adding sodium sulfite solution to the filtered clear liquid to decompose the hydrogen peroxide contained therein to obtain the material to be extracted; The extraction process: the material to be extracted is input into the extraction tower, and the oil phase is extracted from the top of the tower, and the oil phase is input into the refining process; Extracting a water phase from the bottom of the extraction tower; The refining process comprises the following steps: S1, the oil phase output from the extraction step is input into an extractant recovery tower; the top product of the extractant recovery tower is subjected to phase separation treatment by a first phase separation device to obtain an extractant, and the bottom product is input into a phenol removal tower; S2, the overhead product of the first phenol removal tower is subjected to phase separation treatment by a second phase separation device to obtain phenol, and the bottom product is input into a detarring tower; S3, the overhead product of the detarring tower is input into the second dephenolizing tower, and the bottom of the tower produces the material containing tar; S4, phenol is extracted from the top of the second dephenolization tower, and the bottom extract is input into a catechol tower; S5, extracting catechol from the top of the catechol tower, and inputting the extract from the bottom of the tower into a light-removal tower; S6, extracting light component impurities from the top of the light removal tower, and inputting the materials in the bottom of the tower into a hydroquinone tower; S7, extracting hydroquinone from the top of the hydroquinone tower, and extracting heavy impurities from the bottom of the tower.

2. The continuous production process of o-hydroquinone according to claim 1, characterized in that: The overhead products of the first dephenolization tower, the detarring tower and the second dephenolization tower are heat exchanged with water to obtain a gas-liquid mixture, and the gas-liquid mixture is separated into gas and liquid by a first gas-liquid separation tank and compressed by a first steam compressor to obtain secondary steam A; Preferably, the secondary steam A is 300-600kPaA steam; Preferably, the secondary steam A is used for preheating raw materials, heating the hydrogen peroxide decomposition process, heating the reboiler of the extractant recovery tower, and heating the equipment and pipelines in step S1.

3. The continuous production process of o-hydroquinone according to claim 2, characterized in that: The secondary steam A is compressed by the second steam compressor to obtain recompressed steam; Preferably, the recompressed steam is 1000-1500 kPaA steam; Preferably, the recompressed steam is used for heating the equipment and pipelines in steps S2 to S7; Further preferably, the recompressed steam is passed through a third steam compressor to obtain tertiary compressed steam; Still further preferably, the tertiary compressed steam is 3500-4200 kPaA steam; Still further preferably, the tertiary compressed steam is used for heating the reboiler of the dephenolization tower.

4. The continuous production process of o-hydroquinone and o-hydroquinone according to any one of claims 1 to 3, characterized in that: The overhead products of the light-removal tower and the hydroquinone tower are heat exchanged with the heat transfer oil, and the heat transfer oil after the heat exchange generates a gas-liquid mixture in the steam generator, and the gas-liquid mixture is separated into gas and liquid in the second gas-liquid separation tank to obtain secondary steam B; Preferably, the secondary steam B is 300-600 kPaA steam; Preferably, the secondary steam B is used for preheating raw materials, heating the hydrogen peroxide decomposition process, heating the reboiler of the extractant recovery tower, and heating the equipment and pipelines of step S1.

5. The continuous production process of o-hydroquinone and o-hydroquinone according to claim 4, characterized in that: The liquid phase in the second gas-liquid separation tank is heat exchanged with the steam generator and the catechol tower top extraction respectively, and then input into Branch 1, a gas-liquid mixture is generated by the steam generator and returned to the second gas-liquid separation tank, and secondary steam B is obtained by gas-liquid separation, and the obtained liquid phase is sent to the steam generator; And / or, branch 2, after heat exchange with the overhead product of the catechol tower, a gas-liquid mixture is generated and then returned to the second gas-liquid separation tank, and secondary steam B is obtained through gas-liquid separation, and the obtained liquid phase is then heat exchanged with the overhead product of the catechol tower; It is circulated through branch 1 and branch 2.

6. The continuous production process of o-hydroquinone and o-hydroquinone according to claim 1, characterized in that: Outputting light component impurities from the side sampling port of the second dephenolization tower; Preferably, the light component impurities extracted from the side of the second phenol removal tower and the light component impurities extracted from the top of the light removal tower are input into the subsequent impurity treatment process; And / or, the heavy impurities extracted from the bottom of the hydroquinone tower are input into the detarring tower.

7. The continuous production process of o-hydroquinone and o-hydroquinone according to claim 1, characterized in that: The concentration of the hydrogen peroxide does not exceed 30%; And / or, the extractant comprises at least one of di-n-butyl ether, diisobutyl ether, di-sec-butyl ether, diisopropyl ether, di-n-propyl ether, diamyl ether, methyl isobutyl ketone, 2-pentanone and 3-pentanone, preferably di-n-butyl ether or diisopropyl ether.

8. The continuous production process of o-hydroquinone and o-hydroquinone according to claim 1, characterized in that: The operating temperature range of the reaction process is 60-90°C, and the operating pressure is 100-300kPaA; And / or, the operating parameters of the extraction tower are: tower top temperature 25-45°C, tower bottom temperature 30-50°C, tower top operating pressure 100-200 kPaA; And / or, the operating parameters of the dephenolization tower are: tower top temperature 50-150°C, tower bottom temperature 190-220°C, operating pressure 50-150 kPaA, reflux ratio 0.1-2, theoretical plate number 15-30, feed position 10-15; And / or, the operating parameters of the detarring tower are: tower top temperature 50-150°C, tower bottom temperature 200-300°C, operating pressure 0.5-10 kPaA, reflux ratio 0.5-5, theoretical plate number 15-30, feed position 10-15; And / or, the operating parameters of the second dephenolization tower are: tower top temperature 50-150°C, tower bottom temperature 100-300°C, operating pressure 0.5-10 kPaA, reflux ratio 0.5-5, theoretical plate number 15-30, feed position 10-15; And / or, the operating parameters of the catechol tower are: tower top temperature 150-180°C, tower bottom temperature 200-230°C, operating pressure 5-10 kPaA, reflux ratio 0.5-5, theoretical plate number 20-40, feed position 15-25; And / or, the operating parameters of the lightness removal tower are: tower top temperature 170-200°C, tower bottom temperature 180-230°C, operating pressure 5-10 kPaA, reflux ratio 0.5-5, theoretical plate number 20-40, feed position 10-20; And / or, the operating parameters of the hydroquinone tower are: tower top temperature 170-200°C, tower bottom temperature 180-230°C, operating pressure 5-10 kPaA, reflux ratio 0.5-5, theoretical plate number 20-40, and feed position 15-25.

9. The continuous production process of o-hydroquinone and o-hydroquinone according to claim 1, characterized in that: The process also includes a wastewater treatment step: the water phase extracted from the bottom of the extraction tower is input into a stripping tower; the top of the stripping tower is input into a first phase separation device, and the bottom of the tower outputs wastewater; Preferably, the operating parameters of the stripping tower are: tower top temperature 100-150°C, tower bottom temperature 100-150°C, operating pressure 100-200 kPaA, withdrawal-feed ratio 0.1-1, theoretical plate number 5-10, and feed position 1-5.

10. The continuous production process of o-hydroquinone and o-hydroquinone according to claim 1, characterized in that: The process also includes a tail gas treatment step, wherein the primary tail gas generated by the reaction step, the filtration step, and the hydrogen peroxide decomposition step is subjected to multi-stage water washing to obtain secondary tail gas, the secondary tail gas is discharged after being adsorbed by activated carbon, and the obtained washing liquid is recycled; And / or, the method further comprises a catalyst regeneration step: drying and calcining the solid phase catalyst separated in the filtering step to activate the catalyst; And / or, it also includes a product packaging step, outputting the catechol product and the hydroquinone product through tableting and packaging.

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