Process for the production of benzenediols and production plant

Abstract

The application provides a production method and a production device of a benzenediol. The production method comprises the following steps: feeding phenol and hydrogen peroxide into a first shell-and-tube reactor provided with a catalyst to perform a hydroxylation reaction; feeding a first circulating medium into the shell of the first shell-and-tube reactor to make the initial bed temperature be 25-30 DEG C; removing the heat generated by the hydroxylation reaction through the first circulating medium; detecting the inflow temperature and the outflow temperature of the first circulating medium; obtaining a first temperature rise estimation value of the first shell-and-tube reactor according to the specific heat of the material entering the first shell-and-tube reactor, the mass flow of the phenol and the hydrogen peroxide, the specific heat of the first circulating medium, the flow of the first circulating medium, the inflow temperature and the outflow temperature of the first circulating medium; when the first temperature rise estimation value is lower than a preset temperature rise value, increasing the inflow temperature of the first circulating medium by a first preset temperature value; and replacing the catalyst of the first shell-and-tube reactor when the bed temperature of the first shell-and-tube reactor reaches 45-50 DEG C.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical production, in particular to a production method and a production device of phenylenediols. BACKGROUND

[0002] Catechol and hydroquinone are important chemical products, catechol is widely used in the fields of pharmaceutical intermediates, dyes and photosensitive materials, rubber and plastics, etc.; hydroquinone can be used in the fields of developing agents, polymerization inhibitors, antioxidants, dyes and perfumes, medicines and pesticides, etc.

[0003] In industry, phenol and hydrogen peroxide are usually used as raw materials to produce catechol and hydroquinone under normal temperature, acidic environment and metal catalyst system, and the reaction equation is as follows: C6H5OH + H2O2→ C6H4(OH)2 + H2O. By controlling the conditions of the reaction, hydrogen peroxide can hydroxylate phenol to produce catechol and hydroquinone, and the mass ratio of catechol in the target product is about 65%~70%, and the mass ratio of hydroquinone is about 30%~35%.

[0004] The reaction is a strong exothermic reaction and is prone to side reactions. During the reaction process, when the temperature reaches above 60℃, side reactions may occur to generate tar, which can block the catalyst bed and reduce the yield of the target product, and even cause production interruption. In addition, as the reaction proceeds, the catalyst will age and its catalytic activity will decrease, so the bed temperature needs to be increased to improve the catalyst activity and maintain the reaction. When the catalyst cannot completely convert the raw materials, the production needs to be stopped and new catalysts need to be replaced. Therefore, the control of the bed temperature of the reactor is extremely important.

[0005] The traditional production method is to directly detect the bed temperature of the reactor by a temperature sensor, and then to maintain the stability of the bed temperature of the reactor by adjusting the temperature of the circulating water. However, this method cannot accurately reflect the actual state of the catalyst, and cannot accurately control the reaction temperature according to the actual state of the catalyst. Therefore, how to more accurately and scientifically control the reaction temperature, and thus reduce the side reactions and improve the yield of the target product, has become one of the important research directions in the field. SUMMARY

[0006] Based on this, the present application provides a production method and a production device of phenylenediols, which can accurately control the temperature rise of the reaction according to the state of the catalyst, and is beneficial to reduce the side reactions and improve the yield of the target product.

[0007] The technical solution provided by the present application is as follows:

[0008] According to the first aspect of the present application, a production method of phenylenediols is provided, comprising the following steps:

[0009] Phenol and hydrogen peroxide are introduced into a first tubular reactor containing a catalyst in the tube side for hydroxylation reaction. A first circulating medium is introduced into the shell side of the first tubular reactor to control the initial bed temperature of the first tubular reactor to be 25°C~30°C. The heat generated by the hydroxylation reaction is removed through the first circulating medium.

[0010] The inflow and outflow temperatures of the first circulating medium are detected; and based on the specific heat of the material entering the first tubular reactor, the mass flow rates of phenol and hydrogen peroxide, the specific heat of the first circulating medium, the flow rate of the first circulating medium, and the inflow and outflow temperatures of the first circulating medium, the first temperature rise estimate of the first tubular reactor is obtained.

[0011] When the first temperature rise estimate is lower than the preset temperature rise value, the inflow temperature of the first circulating medium is increased by the first preset temperature value; when the bed temperature of the first tubular reactor reaches 45℃~50℃, the catalyst in the first tubular reactor is replaced.

[0012] In some implementations, the first temperature rise estimate of the first tubular reactor is obtained using the following formula:

[0013] TDIC1 = CP 介质 m 介质 (T) 介质出 -T 介质入 ) / CP1 (m 苯酚 + m 双氧水 );

[0014] Among them, TDIC1 is the first temperature rise estimate; CP 介质 The specific heat of the first circulating medium; m 介质 T is the mass flow rate of the first circulating medium. 介质出 T is the outlet temperature of the first circulating medium. 介质入 The inflow temperature of the first circulating medium is CP1; the specific heat of the material entering the first tubular reactor is m. 苯酚 The mass flow rate of phenol is m. 双氧水 This represents the mass flow rate of hydrogen peroxide.

[0015] In some embodiments, the preset temperature rise value is 10℃~15℃, and the first preset temperature value is 25℃~30℃.

[0016] In some embodiments, the reaction liquid after reaction in the first tubular reactor is passed into a second tubular reactor containing a catalyst to carry out the hydroxylation reaction. A second circulating medium is introduced into the shell side of the second tubular reactor to control the initial bed temperature of the second tubular reactor to be 25°C~30°C. The heat generated by the hydroxylation reaction is removed through the second circulating medium.

[0017] detecting the inflow temperature and the outflow temperature of the second circulating medium; and obtaining a second temperature rise estimation value of the second shell-and-tube reactor according to the specific heat of the material entering the second shell-and-tube reactor, the mass flow of the phenol and the hydrogen peroxide, the specific heat of the second circulating medium, the flow of the second circulating medium, the inflow temperature and the outflow temperature of the second circulating medium;

[0018] when the second temperature rise estimation value is lower than a preset temperature rise value, increasing the inflow temperature of the second circulating medium by a first preset temperature value.

[0019] In some embodiments, the reaction liquid after the reaction in the second shell-and-tube reactor is introduced into a third shell-and-tube reactor containing a catalyst for hydroxylation reaction, a third circulating medium is introduced into the shell side of the third shell-and-tube reactor to control the initial bed temperature of the third shell-and-tube reactor to be 25-30℃; and the heat generated by the hydroxylation reaction is removed by the third circulating medium.

[0020] detecting the inflow temperature and the outflow temperature of the third circulating medium; and obtaining a third temperature rise estimation value of the third shell-and-tube reactor according to the specific heat of the material entering the third shell-and-tube reactor, the mass flow of the phenol and the hydrogen peroxide, the specific heat of the third circulating medium, the flow of the third circulating medium, the inflow temperature and the outflow temperature of the third circulating medium;

[0021] when the third temperature rise estimation value is lower than a preset temperature rise value, increasing the inflow temperature of the third circulating medium by a first preset temperature value.

[0022] In some embodiments, the reaction liquid after the reaction in the third shell-and-tube reactor is introduced into a protective bed reactor containing a reducing protective agent.

[0023] detecting the temperature rise value of the protective bed reactor; and when the temperature rise value of the protective bed reactor reaches 2-5℃, replacing the catalysts in the first shell-and-tube reactor, the second shell-and-tube reactor and the third shell-and-tube reactor.

[0024] According to a second aspect of the present application, a device for producing a diphenol is provided, which comprises a first shell-and-tube reactor, a first bed temperature meter and a first circulating heat removal unit.

[0025] The tube side of the first shell-and-tube reactor contains a catalyst for catalyzing the hydroxylation reaction of phenol and hydrogen peroxide.

[0026] The first bed temperature meter is arranged on the first shell-and-tube reactor and is used to detect the bed temperature of the first shell-and-tube reactor.

[0027] The first circulating heat transfer unit comprises a first circulating medium inflow pipe, a first circulating medium storage tank, a first circulating medium outflow pipe, a first inflow thermometer, a first outflow thermometer, a first heater, a first cooler and a first controller; one end of the first circulating medium inflow pipe is in communication with the rear end of the shell side of the first shell-and-tube reactor, and the other end is in communication with the liquid outlet of the first circulating medium storage tank; one end of the first circulating medium outflow pipe is in communication with the front end of the shell side of the first shell-and-tube reactor, and the other end is in communication with the liquid inlet of the first circulating medium storage tank; the first inflow thermometer, the first heater and the first cooler are all arranged on the first circulating medium inflow pipe; the first outflow thermometer is arranged on the first circulating medium outflow pipe; the first bed temperature thermometer, the first inflow thermometer and the first outflow thermometer are all electrically connected with the input end of the first controller, and the first heater and the first cooler are both electrically connected with the output end of the first controller.

[0028] In some embodiments, the production device further comprises a second shell-and-tube reactor, a second bed temperature thermometer and a second circulating heat transfer unit;

[0029] The feed end of the second shell-and-tube reactor is in communication with the discharge end of the first shell-and-tube reactor; and the tube side of the second shell-and-tube reactor is provided with a catalyst for catalyzing the hydroxylation reaction of phenol and hydrogen peroxide;

[0030] The second bed temperature thermometer is arranged on the second shell-and-tube reactor and is used for detecting the bed temperature of the second shell-and-tube reactor;

[0031] The second circulating heat transfer unit comprises a second circulating medium inflow pipe, a second circulating medium storage tank, a second circulating medium outflow pipe, a second inflow thermometer, a second outflow thermometer, a second heater, a second cooler and a second controller; one end of the second circulating medium inflow pipe is in communication with the rear end of the shell side of the second shell-and-tube reactor, and the other end is in communication with the liquid outlet of the second circulating medium storage tank; one end of the second circulating medium outflow pipe is in communication with the front end of the shell side of the second shell-and-tube reactor, and the other end is in communication with the liquid inlet of the second circulating medium storage tank; the second inflow thermometer, the second heater and the second cooler are all arranged on the second circulating medium inflow pipe; the second outflow thermometer is arranged on the second circulating medium outflow pipe; the second bed temperature thermometer, the second inflow thermometer and the second outflow thermometer are all electrically connected with the input end of the second controller, and the second heater and the second cooler are both electrically connected with the output end of the second controller.

[0032] In some embodiments, the production device further comprises a third shell-and-tube reactor, a third bed temperature thermometer and a third circulating heat transfer unit;

[0033] The feed end of the third tubular reactor is communicated with the discharge end of the second tubular reactor; and the tube passage of the third tubular reactor is filled with a catalyst for catalyzing the hydroxylation reaction of phenol and hydrogen peroxide;

[0034] The third bed temperature gauge is arranged on the third tubular reactor and is used for detecting the bed temperature of the third tubular reactor;

[0035] The third circulating heat removal unit comprises a third circulating medium inflow pipe, a third circulating medium storage tank, a third circulating medium outflow pipe, a third inflow temperature gauge, a third outflow temperature gauge, a third heater, a third cooler and a third controller; one end of the third circulating medium inflow pipe is communicated with the rear end of the shell passage of the third tubular reactor, and the other end is communicated with the liquid outlet of the third circulating medium storage tank; one end of the third circulating medium outflow pipe is communicated with the front end of the shell passage of the third tubular reactor, and the other end is communicated with the liquid inlet of the third circulating medium storage tank; the third inflow temperature gauge, the third heater and the third cooler are arranged on the third circulating medium inflow pipe; the third outflow temperature gauge is arranged on the third circulating medium outflow pipe; the third bed temperature gauge, the third inflow temperature gauge and the third outflow temperature gauge are electrically connected with the input end of the third controller, and the third heater and the third cooler are electrically connected with the output end of the third controller.

[0036] In some embodiments, the production device further comprises a guard bed reactor, a guard bed temperature gauge and a fourth controller;

[0037] The feed end of the guard bed reactor is communicated with the discharge end of the third tubular reactor; and the guard bed reactor is filled with a reducing guard agent;

[0038] The guard bed temperature gauge is arranged on the guard bed reactor and is used for detecting the temperature in the guard bed reactor; and the guard bed temperature gauge is electrically connected with the input end of the fourth controller.

[0039] Compared with the conventional technology, the present application has at least the following beneficial effects:

[0040] The production method of the present application controls the initial bed temperature in a lower range to avoid over-temperature in the initial stage of the reaction, because the catalyst has high activity and the reaction rate is fast in the initial stage of the reaction, and a large amount of heat is released. The heat generated in the hydroxylation reaction is removed by the first circulating medium, and the first temperature rise prediction value of the first tube reactor is obtained according to the removed heat, which can accurately reflect the state of the catalyst. When the first temperature rise prediction value is lower than the preset temperature rise value, the inflow temperature of the first circulating medium is increased by the first preset temperature value, and then the bed temperature is increased to improve the activity of the catalyst and maintain the reaction. The above method can determine the state of the catalyst according to the heat generated in the reaction, and then accurately control the bed temperature of the tube reactor, so that the catalyst can catalyze the hydroxylation reaction in a better state. The production method can accurately control the bed temperature according to the state of the catalyst, which is beneficial to reduce the side reaction, improve the yield of the target product and the utilization rate of the catalyst. BRIEF DESCRIPTION OF DRAWINGS

[0041] For better describing and illustrating the embodiments or examples provided by the present application, one or more drawings can be referred to. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any one of the disclosed applications, the presently described embodiments or examples, and the best mode presently understood of these applications. Moreover, the same reference numbers are used throughout the drawings to represent the same components. In the drawings:

[0042] Figure 1 The structure schematic diagram of the production device of an embodiment of the present application.

[0043] Figure 2 The connection schematic diagram of the first circulating heat removal unit and the first tube reactor in the production device of an embodiment of the present application.

[0044] Explanation of reference signs:

[0045] 10, production device; 11, first tube reactor; 12, first bed temperature gauge; 13, first circulating heat removal unit; 14, second tube reactor; 15, third tube reactor; 16, guard bed reactor; 17, static mixer; 18, heat exchanger; 131, first circulating medium inflow pipe; 132, first circulating medium storage tank; 133, first circulating medium outflow pipe; 134, first inflow temperature gauge; 135, first outflow temperature gauge; 136, first heater; 137, first cooler; 138, first controller. DETAILED DESCRIPTION

[0046] In order to make the above objectives, features and advantages of the present application more clear and comprehensible, the specific embodiments of the present application are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in a number of different ways without being limited to the embodiments described herein below, and it is understood that it will be encompassed in the scope of the present application to carry out similar modifications or deformations by those skilled in the art without departing from the spirit and scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0047] In addition, the terms "first", "second", etc. are used only for the purpose of description, and should not be understood as indicating or implying relative importance or implying the number of the technical features indicated. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "plurality" is at least two, for example, two, three, etc., unless otherwise explicitly specified.

[0048] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing", etc. should be understood in a broad sense, for example, can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be directly connected, or indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the specification of the present application is only for the purpose of describing specific embodiments of the present application, and is not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0050] An embodiment of the present application provides a method for producing a benzenediol, the method comprising the steps of:

[0051] The phenol and hydrogen peroxide are introduced into a first shell-and-tube reactor provided with a catalyst to perform a hydroxylation reaction, a first circulating medium is introduced into the shell of the first shell-and-tube reactor to control the initial bed temperature of the first shell-and-tube reactor to be 25-30°C, and the heat generated by the hydroxylation reaction is removed through the first circulating medium; the inflow temperature and outflow temperature of the first circulating medium are detected; and based on the specific heat of the material introduced into the first shell-and-tube reactor, the mass flow of the phenol and hydrogen peroxide, the specific heat of the first circulating medium, the flow of the first circulating medium, the inflow temperature and outflow temperature of the first circulating medium, the first temperature rise estimation value of the first shell-and-tube reactor is obtained; when the first temperature rise estimation value is lower than the preset temperature rise value, the inflow temperature of the first circulating medium is increased by a first preset temperature value; when the bed temperature of the first shell-and-tube reactor reaches 45-50°C, the catalyst in the first shell-and-tube reactor is replaced.

[0052] The production method described above controls the initial bed temperature of the first shell-and-tube reactor to be relatively low, which is beneficial to avoid over-temperature at the initial stage of the reaction, because the catalyst has high activity and fast reaction rate at the initial stage of the reaction, and a large amount of heat is generated. The heat generated by the reaction is proportional to the activity of the catalyst under the condition of a constant raw material flow, and the heat generated by the hydroxylation reaction is removed through the first circulating medium, and the first temperature rise estimation value of the first shell-and-tube reactor is obtained based on the removed heat, which can accurately reflect the state of the catalyst. As the reaction proceeds, the activity of the catalyst decreases, and the heat generated by the reaction decreases. When the first temperature rise estimation value is lower than the preset temperature rise value, the inflow temperature of the first circulating medium is increased by a first preset temperature value, thereby increasing the bed temperature and improving the activity of the catalyst to maintain the progress of the reaction. When the bed temperature increases to 45-50°C, a new catalyst is replaced.

[0053] The above method can determine the state of the catalyst according to the heat generated by the reaction, and accurately control the bed temperature of the shell-and-tube reactor, so that the catalyst can catalyze the hydroxylation reaction in a better state. The production method can accurately control the temperature rise of the reaction, which is beneficial to reduce the side reaction, improve the yield of the target product, and improve the utilization rate of the catalyst.

[0054] It can be understood that the catalyst used for the hydroxylation reaction can be a conventional catalyst used for catalyzing the hydroxylation reaction of phenol and hydrogen peroxide in the art, for example, it can be a transition metal salt (such as Fe 2+ ) catalyst. The hydroxylation reaction is performed under acidic conditions, and the pH of the reaction system can be 3-4. The circulating medium can be circulating water, for example.

[0055] In some specific examples, the initial bed temperature of the first tubular reactor is controlled at 30℃; and the catalyst in the first tubular reactor is replaced when the bed temperature of the first tubular reactor reaches 45℃.

[0056] In some of the embodiments, the first temperature rise estimation value of the first tubular reactor is obtained by the following formula:

[0057] TDIC1=CP 介质 m 介质 (T 介质出 -T 介质入 ) / CP1(m 苯酚 +m 双氧水 );

[0058] wherein TDIC1 is the first temperature rise estimation value, in ℃; CP 介质 is the specific heat of the first circulating medium, in J / (kg·℃); m 介质 is the mass flow of the first circulating medium, in kg / h; T 介质出 is the outflow temperature of the first circulating medium, in ℃; T 介质入 is the inflow temperature of the first circulating medium, in ℃; CP1 is the specific heat of the material entering the first tubular reactor, in J / (kg·℃); m 苯酚 is the mass flow of phenol, in kg / h; and m 双氧水 is the mass flow of hydrogen peroxide, in kg / h.

[0059] In the life cycle of the catalyst, the selectivity changes little, and in the case of ensuring the constant flow of phenol and hydrogen peroxide in the feed, the total production capacity of the generated catechol and hydroquinone corresponds to the total heat of the reactor, and the higher the heat, the higher the production capacity. The heat of the reactor is removed by circulating water, and according to the heat balance, we can get:

[0060] Q=CP1(m 苯酚 + m 双氧水 )TDIC1=CP 介质 m 介质 (T 介质出 -T 介质入 );

[0061] i.e. TDIC1=CP 介质 m 介质 (T 介质出 -T 介质入 ) / CP1(m 苯酚 +m 双氧水 )。

[0062] Through the above formula, the first temperature rise estimation value of the first tubular reactor can be determined, and the state of the catalyst can be judged.

[0063] In some embodiments, the preset temperature rise value is 10-15℃, and the first preset temperature value is 25-30℃. When the first temperature rise estimation value is lower than the preset temperature rise value, the inflow temperature of the first circulating medium is increased by the first preset temperature value, which is more conducive to accurately controlling the bed temperature according to the state of the catalyst.

[0064] In some embodiments, the reaction liquid after the reaction in the first shell-and-tube reactor is introduced into a second shell-and-tube reactor containing a catalyst for a hydroxylation reaction, a second circulating medium is introduced into the shell side of the second shell-and-tube reactor to control the initial bed temperature of the second shell-and-tube reactor to be 25-30℃, and the heat generated by the hydroxylation reaction is removed by the second circulating medium; the inflow temperature and the outflow temperature of the second circulating medium are detected; and the second temperature rise estimation value of the second shell-and-tube reactor is obtained according to the specific heat of the material entering the second shell-and-tube reactor, the mass flow of phenol and hydrogen peroxide, the specific heat of the second circulating medium, the flow of the second circulating medium, the inflow temperature and the outflow temperature of the second circulating medium; when the second temperature rise estimation value is lower than the preset temperature rise value, the inflow temperature of the second circulating medium is increased by the first preset temperature value.

[0065] In this way, the multiple shell-and-tube reactors are connected in series, so that the reaction liquid after the reaction in the first shell-and-tube reactor continues to perform a hydroxylation reaction in the second shell-and-tube reactor, which is more conducive to making the raw materials fully react and improving the reaction yield. In the reaction process of the second shell-and-tube reactor, the state of the catalyst is also judged by the temperature rise of the circulating water, and then the bed temperature is controlled, which is more conducive to reducing side reactions, improving the yield of the target product, and improving the utilization rate of the catalyst.

[0066] In some embodiments, the reaction liquid after the reaction in the second shell-and-tube reactor is introduced into a third shell-and-tube reactor containing a catalyst, a third circulating medium is introduced into the shell side of the third shell-and-tube reactor to control the initial bed temperature of the third shell-and-tube reactor to be 25-30℃ for a hydroxylation reaction, and the heat generated by the hydroxylation reaction is removed by the third circulating medium; the inflow temperature and the outflow temperature of the third circulating medium are detected; and the third temperature rise estimation value of the third shell-and-tube reactor is obtained according to the specific heat of the material entering the third shell-and-tube reactor, the mass flow of phenol and hydrogen peroxide, the specific heat of the third circulating medium, the flow of the third circulating medium, the inflow temperature and the outflow temperature of the third circulating medium; when the third temperature rise estimation value is lower than the preset temperature rise value, the inflow temperature of the third circulating medium is increased by the first preset temperature value.

[0067] Therefore, the first, second and third tubular reactors are connected in series, so that the reaction solution after the reaction in the second tubular reactor continues to flow into the third tubular reactor to continue the hydroxylation reaction, which is more conducive to the full reaction of the raw material and the improvement of the reaction yield. In the reaction process of the third tubular reactor, the temperature rise of the circulating water is also used to determine the state of the catalyst, and then the bed temperature is controlled, which is more conducive to reducing side reactions, improving the yield of the target product, and improving the utilization rate of the catalyst. Moreover, the reaction is carried out in multiple series-connected tubular reactors, and the bed temperature is controlled by the temperature rise, which can well distribute the production capacity among the multiple tubular reactors according to the temperature rise.

[0068] In some embodiments, the reaction solution after the reaction in the third tubular reactor is introduced into a guard bed reactor containing a reducing protective agent; the temperature rise of the guard bed reactor is detected; when the temperature rise of the guard bed reactor reaches 2-5°C, the catalysts in the first, second and third tubular reactors are replaced.

[0069] In the production process of phenol and hydrogen peroxide using a tubular reactor, the phenol is usually excessive relative to the hydrogen peroxide, which is conducive to improving the selectivity and safety of the reaction. The guard bed reactor containing a reducing protective agent is arranged at the rear end of the third tubular reactor. When the first, second and third tubular reactors can fully catalyze the reaction, no hydrogen peroxide will enter the guard bed reactor; when the catalyst cannot fully convert the hydrogen peroxide, the unreacted hydrogen peroxide will enter the guard bed reactor and react with the reducing protective agent to generate heat, causing the temperature of the guard bed reactor to rise.

[0070] By detecting the temperature rise of the guard bed reactor, it can be determined whether the catalyst in the tubular reactor needs to be replaced. When the temperature rise of the guard bed reactor reaches the above value, it means that the catalyst in the tubular reactor needs to be replaced. Understandably, the temperature rise of the guard bed reactor and the bed temperature of the first tubular reactor only need to meet one of the conditions, and the catalyst in the tubular reactor needs to be replaced.

[0071] When replacing the catalyst, the catalysts in the first, second and third tubular reactors can be removed and replaced with new catalysts. Since the catalyst in the first tubular reactor loses catalytic activity, the catalysts in the second and third tubular reactors still have certain catalytic activity; therefore, the catalyst in the first tubular reactor can be removed, the catalyst in the second tubular reactor can be loaded into the first tubular reactor, the catalyst in the third tubular reactor can be loaded into the second tubular reactor, and new catalyst can be loaded into the third tubular reactor.

[0072] Referring to Figure 1 and Figure 2 , an embodiment of the present application provides a production device 10 used in the production method of the above-mentioned catechol, which comprises a first column reactor 11, a first bed temperature meter 12 and a first circulating heat removal unit 13.

[0073] The tube passage of the first column reactor 11 is provided with a catalyst for catalyzing the hydroxylation reaction of phenol and hydrogen peroxide; the first bed temperature meter 12 is arranged on the first column reactor 11 and used for detecting the bed temperature of the first column reactor 11.

[0074] The first circulating heat removal unit 13 comprises a first circulating medium inflow pipe 131, a first circulating medium storage tank 132, a first circulating medium outflow pipe 133, a first inflow temperature meter 134, a first outflow temperature meter 135, a first heater 136, a first cooler 137 and a first controller 138; one end of the first circulating medium inflow pipe 131 is in communication with the rear end of the shell passage of the first column reactor 11, and the other end is in communication with the liquid outlet of the first circulating medium storage tank 132; one end of the first circulating medium outflow pipe 133 is in communication with the front end of the shell passage of the first column reactor 11, and the other end is in communication with the liquid inlet of the first circulating medium storage tank 132; the first inflow temperature meter 134, the first heater 136 and the first cooler 137 are all arranged on the first circulating medium inflow pipe 131; the first outflow temperature meter 135 is arranged on the first circulating medium outflow pipe 133; the first bed temperature meter 12, the first inflow temperature meter 134 and the first outflow temperature meter 135 are all electrically connected with the input end of the first controller 138, and the first heater 136 and the first cooler 137 are all electrically connected with the output end of the first controller 138.

[0075] When the first column reactor 11 is working, the raw materials phenol and hydrogen peroxide are fed into the tube passage from the feed end of the first column reactor 11, and the hydroxylation reaction occurs under the action of the catalyst arranged in the tube passage. The bed temperature is detected by the first bed temperature meter 12 and the bed temperature signal is sent to the first controller 138; the first controller 138 adjusts the inflow temperature of the first circulating medium by controlling the valve opening degree of the first heater 136 and the first cooler 137, so as to maintain the initial bed temperature at 25-30°C (such as 30°C).

[0076] The heat generated in the reaction is continuously removed from the reactor by the first circulating medium. The first controller 138 adjusts the valve opening degree of the first heater 136 and the first cooler 137 according to TDIC1=CP 介质 m 介质 (T 介质出 -T 介质入 ) / CP1(m 苯酚 +m 双氧水) to obtain a first temperature rise estimation of the reaction. As the reaction proceeds, the activity of the catalyst gradually decreases, the heat released by the reaction decreases, and the first temperature rise estimation decreases. When the first temperature rise estimation is lower than the preset temperature rise value, the first controller 138 increases the inflow temperature of the first circulating medium by a first preset temperature value by controlling the valve opening of the first heater 136 and the first cooler 137, thereby increasing the bed temperature and keeping the catalyst in a good activity. As the reaction continues, the bed temperature gradually increases. When the bed temperature reaches 45°C to 50°C (e.g., 45°C), the first controller 138 issues a catalyst replacement instruction and stops to replace the catalyst in the first tubular reactor 11.

[0077] Specifically, when the inflow temperature of the first circulating medium needs to be increased, the first controller 138 controls the valve opening of the first heater 136 to increase and the valve opening of the first cooler 137 to decrease, thereby increasing the inflow temperature of the first circulating medium. When the inflow temperature of the first circulating medium needs to be decreased, the first controller 138 controls the valve opening of the first heater 136 to decrease and the valve opening of the first cooler 137 to increase, thereby decreasing the inflow temperature of the first circulating medium.

[0078] In this way, by using the production device 10 and the control logic described above, the state of the catalyst can be determined according to the heat generated by the reaction, and the bed temperature of the first tubular reactor 11 can be accurately controlled, so that the catalyst can catalyze the hydroxylation reaction in a good state. The production device 10 can accurately control the temperature rise of the reaction, which is beneficial to reduce side reactions, improve the yield of the target product, and improve the utilization rate of the catalyst.

[0079] In some embodiments, the production device 10 further includes a second tubular reactor 14, a second bed temperature gauge (not shown in the figure), and a second circulating heat removal unit (not shown in the figure).

[0080] The feed end of the second tubular reactor 14 is in communication with the discharge end of the first tubular reactor 11. The tube side of the second tubular reactor 14 is provided with a catalyst for catalyzing the hydroxylation reaction of phenol and hydrogen peroxide. The second bed temperature gauge is arranged on the second tubular reactor 14 to detect the bed temperature of the second tubular reactor 14.

[0081] The second circulating heat transfer unit comprises a second circulating medium inflow pipe, a second circulating medium storage tank, a second circulating medium outflow pipe, a second inflow thermometer, a second outflow thermometer, a second heater, a second cooler and a second controller. One end of the second circulating medium inflow pipe is in communication with the rear end of the shell side of the second shell-and-tube reactor 14, and the other end is in communication with the liquid outlet of the second circulating medium storage tank. One end of the second circulating medium outflow pipe is in communication with the front end of the shell side of the second shell-and-tube reactor 14, and the other end is in communication with the liquid inlet of the second circulating medium storage tank. The second inflow thermometer, the second heater and the second cooler are all arranged on the second circulating medium inflow pipe. The second outflow thermometer is arranged on the second circulating medium outflow pipe. The second bed temperature thermometer, the second inflow thermometer and the second outflow thermometer are all electrically connected to the input end of the second controller, and the second heater and the second cooler are both electrically connected to the output end of the second controller.

[0082] The structure, working principle and control logic of the second shell-and-tube reactor 14, the second bed temperature thermometer and the second circulating heat transfer unit are consistent with those of the first shell-and-tube reactor 11, the first bed temperature thermometer and the first circulating heat transfer unit 13. Here, no further description is given.

[0083] In some embodiments, the production device 10 further comprises a third shell-and-tube reactor 15, a third bed temperature thermometer (not shown in the figure) and a third circulating heat transfer unit (not shown in the figure).

[0084] The feed end of the third shell-and-tube reactor 15 is in communication with the discharge end of the second shell-and-tube reactor 14. The tube side of the third shell-and-tube reactor 15 is provided with a catalyst for catalyzing the hydroxylation reaction of phenol and hydrogen peroxide. The third bed temperature thermometer is arranged on the third shell-and-tube reactor 15 for detecting the bed temperature of the third shell-and-tube reactor 15.

[0085] The third circulating heat transfer unit comprises a third circulating medium inflow pipe, a third circulating medium storage tank, a third circulating medium outflow pipe, a third inflow thermometer, a third outflow thermometer, a third heater, a third cooler and a third controller. One end of the third circulating medium inflow pipe is in communication with the rear end of the shell side of the third shell-and-tube reactor 15, and the other end is in communication with the liquid outlet of the third circulating medium storage tank. One end of the third circulating medium outflow pipe is in communication with the front end of the shell side of the third shell-and-tube reactor 15, and the other end is in communication with the liquid inlet of the third circulating medium storage tank. The third inflow thermometer, the third heater and the third cooler are all arranged on the third circulating medium inflow pipe. The third outflow thermometer is arranged on the third circulating medium outflow pipe. The third bed temperature thermometer, the third inflow thermometer and the third outflow thermometer are all electrically connected to the input end of the third controller, and the third heater and the third cooler are both electrically connected to the output end of the third controller.

[0086] The structure, working principle and control logic of the third tubular reactor 15, the third bed temperature gauge and the third circulating heat removal unit are consistent with those of the first tubular reactor 11, the first bed temperature gauge and the first circulating heat removal unit 13. Here, no further description is given.

[0087] In some embodiments, the production device 10 further comprises a guard bed reactor 16, a guard bed temperature gauge (not shown in the figure) and a fourth controller (not shown in the figure). The feed end of the guard bed reactor 16 is in communication with the discharge end of the third tubular reactor 15; the guard bed reactor 16 is filled with a reducing protective agent. The guard bed temperature gauge is arranged on the guard bed reactor 16 for detecting the temperature in the guard bed reactor 16; the guard bed temperature gauge is electrically connected to the input end of the fourth controller.

[0088] In the production process of phenol and hydrogen peroxide using tubular reactors, it is generally beneficial to increase the selectivity and safety of the reaction to make the phenol excessive relative to the hydrogen peroxide. The guard bed reactor 16 is an adiabatic reactor, and when the first tubular reactor 11, the second tubular reactor 14 and the third tubular reactor 15 can make the reaction complete, no hydrogen peroxide enters the guard bed reactor, and the guard bed reactor 16 has no temperature rise. When the catalyst cannot completely convert the hydrogen peroxide, the unreacted hydrogen peroxide will enter the guard bed reactor 16 and react with the reducing protective agent to generate heat, causing the temperature of the guard bed reactor 16 to rise. Therefore, the temperature rise of the guard bed reactor 16 serves as an important monitoring index for the hydrogen peroxide slip. The reducing protective agent can use the reducing protective agent commonly used in the art, such as a sulfite reducing protective agent.

[0089] The temperature rise value of the guard bed reactor 16 detected by the guard bed temperature gauge can be used to determine whether the catalyst in each tubular reactor needs to be replaced. When the temperature rise value of the guard bed reactor 16 reaches a set value (such as 2°C), it indicates that the catalyst in the tubular reactor needs to be replaced, and the fourth controller issues an instruction to replace the catalyst. Moreover, the temperature rise value of the guard bed reactor 16 and the bed temperature of the first tubular reactor 11 only need to meet one of the conditions, and the catalyst in the tubular reactor needs to be replaced.

[0090] In this application, the first controller, the second controller, the third controller and the fourth controller can use a PID controller.

[0091] Please refer to Figure 1In some embodiments, the production apparatus 10 further includes a static mixer 17 and three heat exchangers 18. The static mixer 17 is located at the front end of the first tubular reactor 11 and is used to thoroughly mix the phenol and hydrogen peroxide before they enter the first tubular reactor 11. The three heat exchangers 18 are respectively installed between the first tubular reactor 11 and the second tubular reactor 14, between the second tubular reactor 14 and the third tubular reactor 15, and between the third tubular reactor 15 and the protective bed reactor 16; they are used to adjust the reaction solution to a suitable temperature before it enters the next stage reactor.

[0092] It should be noted that, Figure 1 The first bed thermometer 12, the first circulating heat transfer unit 13, the second bed thermometer, the second circulating heat transfer unit, the third bed thermometer, the third circulating heat transfer unit, the protective bed thermometer, and the fourth controller are not shown in the diagram.

[0093] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0094] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims, and the specification and drawings can be used to interpret the content of the claims.

Claims

1. A method for producing hydroquinone, characterized in that, Includes the following steps: Phenol and hydrogen peroxide are introduced into a first tubular reactor containing a catalyst in the tube side for hydroxylation reaction. A first circulating medium is introduced into the shell side of the first tubular reactor to control the initial bed temperature of the first tubular reactor to be 25°C~30°C. The heat generated by the hydroxylation reaction is removed through the first circulating medium. The inflow and outflow temperatures of the first circulating medium are detected; and based on the specific heat of the material entering the first tubular reactor, the mass flow rates of phenol and hydrogen peroxide, the specific heat of the first circulating medium, the flow rate of the first circulating medium, and the inflow and outflow temperatures of the first circulating medium, the first temperature rise estimate of the first tubular reactor is obtained. When the first temperature rise estimate is lower than the preset temperature rise value, the inflow temperature of the first circulating medium is increased by the first preset temperature value; When the bed temperature of the first tubular reactor reaches 45℃~50℃, the catalyst in the first tubular reactor is replaced.

2. The method for producing hydroquinone according to claim 1, characterized in that, The first estimated temperature rise of the first tubular reactor is determined using the following formula: TDIC1= CP 介质 m 介质 (T 介质出 -T 介质入 ) / CP1 (m 苯酚 + m 双氧水 ); Among them, TDIC1 is the first temperature rise estimate; CP 介质 The specific heat of the first circulating medium; m 介质 T is the mass flow rate of the first circulating medium. 介质出 T is the outlet temperature of the first circulating medium. 介质入 The inflow temperature of the first circulating medium is CP1; the specific heat of the material entering the first tubular reactor is m. 苯酚 The mass flow rate of phenol is m. 双氧水 This represents the mass flow rate of hydrogen peroxide.

3. The method for producing hydroquinone according to claim 1, characterized in that, The preset temperature rise value is 10℃~15℃, and the first preset temperature value is 25℃~30℃.

4. The method for producing hydroquinone according to any one of claims 1 to 3, characterized in that, The reaction liquid after reaction in the first tubular reactor is passed into a second tubular reactor containing a catalyst for hydroxylation reaction. A second circulating medium is introduced into the shell side of the second tubular reactor to control the initial bed temperature of the second tubular reactor to be 25℃~30℃; and the heat generated by the hydroxylation reaction is removed through the second circulating medium. The inflow and outflow temperatures of the second circulating medium are detected; and based on the specific heat of the material entering the second tubular reactor, the mass flow rates of phenol and hydrogen peroxide, the specific heat of the second circulating medium, the flow rate of the second circulating medium, and the inflow and outflow temperatures of the second circulating medium, the second temperature rise estimate of the second tubular reactor is obtained. When the second temperature rise estimate is lower than the preset temperature rise value, the inflow temperature of the second circulating medium is increased by the first preset temperature value.

5. The method for producing hydroquinone according to claim 4, characterized in that, The reaction liquid after reaction in the second tubular reactor is passed into a third tubular reactor containing a catalyst for hydroxylation reaction. A third circulating medium is introduced into the shell side of the third tubular reactor to control the initial bed temperature of the third tubular reactor to be 25°C~30°C; and the heat generated by the hydroxylation reaction is removed through the third circulating medium. The inflow and outflow temperatures of the third circulating medium are detected; and based on the specific heat of the material entering the third tubular reactor, the mass flow rates of phenol and hydrogen peroxide, the specific heat of the third circulating medium, the flow rate of the third circulating medium, and the inflow and outflow temperatures of the third circulating medium, the estimated third temperature rise of the third tubular reactor is obtained. When the estimated third temperature rise is lower than the preset temperature rise value, the inflow temperature of the third circulating medium is increased by the first preset temperature value.

6. The method for producing hydroquinone according to claim 5, characterized in that, The reaction liquid after reaction in the third tubular reactor is passed into a protective bed reactor containing a reducing protective agent; The temperature rise of the protective bed reactor was detected; When the temperature rise of the protective bed reactor reaches 2℃~5℃, the catalyst in the first, second, and third tubular reactors is replaced.

7. A production apparatus for a method of producing hydroquinone according to any one of claims 1 to 6, characterized in that, The production apparatus includes a first tubular reactor, a first bed thermometer, and a first circulating heat transfer unit; The first tubular reactor contains a catalyst in its tube side for catalyzing the hydroxylation reaction of phenol and hydrogen peroxide. The first bed thermometer is installed on the first tubular reactor and is used to detect the bed temperature of the first tubular reactor; The first circulating heat transfer unit includes a first circulating medium inlet pipe, a first circulating medium storage tank, a first circulating medium outlet pipe, a first inlet thermometer, a first outlet thermometer, a first heater, a first cooler, and a first controller. One end of the first circulating medium inlet pipe is connected to the rear end of the shell side of the first tubular reactor, and the other end is connected to the outlet of the first circulating medium storage tank. One end of the first circulating medium outlet pipe is connected to the front end of the shell side of the first tubular reactor, and the other end is connected to the inlet of the first circulating medium storage tank. The first inlet thermometer, the first heater, and the first cooler are all disposed on the first circulating medium inlet pipe. The first outlet thermometer is disposed on the first circulating medium outlet pipe. The first bed thermometer, the first inlet thermometer, and the first outlet thermometer are all electrically connected to the input terminal of the first controller, and the first heater and the first cooler are both electrically connected to the output terminal of the first controller.

8. The production apparatus according to claim 7, characterized in that, The production apparatus also includes a second tubular reactor, a second bed thermometer, and a second circulating heat transfer unit; The feed end of the second tubular reactor is connected to the discharge end of the first tubular reactor; the tube side of the second tubular reactor is filled with a catalyst for catalyzing the hydroxylation reaction of phenol and hydrogen peroxide. The second bed thermometer is installed on the second tubular reactor and is used to detect the bed temperature of the second tubular reactor; The second circulating heat transfer unit includes a second circulating medium inlet pipe, a second circulating medium storage tank, a second circulating medium outlet pipe, a second inlet thermometer, a second outlet thermometer, a second heater, a second cooler, and a second controller. One end of the second circulating medium inlet pipe is connected to the rear end of the shell side of the second tubular reactor, and the other end is connected to the outlet of the second circulating medium storage tank. One end of the second circulating medium outlet pipe is connected to the front end of the shell side of the second tubular reactor, and the other end is connected to the inlet of the second circulating medium storage tank. The second inlet thermometer, the second heater, and the second cooler are all located on the second circulating medium inlet pipe. The second outlet thermometer is located on the second circulating medium outlet pipe. The second bed thermometer, the second inlet thermometer, and the second outlet thermometer are all electrically connected to the input terminal of the second controller, and the second heater and the second cooler are both electrically connected to the output terminal of the second controller.

9. The production apparatus according to claim 8, characterized in that, The production apparatus also includes a third tubular reactor, a third bed thermometer, and a third circulating heat transfer unit; The feed end of the third tubular reactor is connected to the discharge end of the second tubular reactor; the tube side of the third tubular reactor is filled with a catalyst for catalyzing the hydroxylation reaction of phenol and hydrogen peroxide. The third bed thermometer is installed on the third tubular reactor and is used to detect the bed temperature of the third tubular reactor. The third circulating heat transfer unit includes a third circulating medium inlet pipe, a third circulating medium storage tank, a third circulating medium outlet pipe, a third inlet thermometer, a third outlet thermometer, a third heater, a third cooler, and a third controller. One end of the third circulating medium inlet pipe is connected to the rear end of the shell side of the third tubular reactor, and the other end is connected to the outlet of the third circulating medium storage tank. One end of the third circulating medium outlet pipe is connected to the front end of the shell side of the third tubular reactor, and the other end is connected to the inlet of the third circulating medium storage tank. The third inlet thermometer, the third heater, and the third cooler are all located on the third circulating medium inlet pipe. The third outlet thermometer is located on the third circulating medium outlet pipe. The third bed thermometer, the third inlet thermometer, and the third outlet thermometer are all electrically connected to the input terminal of the third controller, and the third heater and the third cooler are both electrically connected to the output terminal of the third controller.

10. The production apparatus according to claim 9, characterized in that, The production apparatus also includes a protective bed reactor, a protective bed thermometer, and a fourth controller; The feed end of the protective bed reactor is connected to the discharge end of the third tubular reactor; the protective bed reactor is filled with a reducing protective agent. The protective bed thermometer is installed on the protective bed reactor and is used to detect the temperature inside the protective bed reactor; The protective bed thermometer is electrically connected to the input terminal of the fourth controller.

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