CN114315503A - Optimization method of reaction system for preparing bisphenol A - Google Patents

Abstract

The invention discloses an optimization method of a reaction system for preparing bisphenol A, which comprises the following steps of sequentially carrying out isomerization reaction, concentration, partial preconcentration, cracking and rearrangement reaction on mother liquor (I) obtained by treating at least one part of reacted liquor; after the reaction system for preparing the bisphenol A operates, the isomerization reaction and the rearrangement reaction are simultaneously carried out in one isomerization rearrangement reactor to form a circulating operation system, and the isopropyl phenol generated in the cracking process enters a phenol recovery system along with light components in the partial pre-concentration process and is separated from phenol along with mixed polyphenol. According to the invention, by optimizing the process of the reaction system for preparing the bisphenol A, on one hand, equipment is reduced by combining reaction devices, the cost is reduced, the process flow is simplified, and the energy consumption is saved. On the other hand, the amount of cumene phenol fed to the condensation reactor is reduced to a reasonable level, extending the service life of the catalyst.

Description

Optimization method of reaction system for preparing bisphenol A

Technical Field

The invention relates to the technical field of bisphenol A production, in particular to an optimization method of a reaction system for preparing bisphenol A.

Background

Bisphenol a (bpa), one of the most widely used industrial compounds in the world, is mainly used for synthesizing materials such as Polycarbonate (PC) and epoxy resin.

Bisphenol A is an important organic chemical raw material which is generally prepared by condensation of two molecules of phenol and one molecule of acetone in the presence of an acidic catalyst, the catalyst which is commonly used in the prior art is sulfonic acid type strong-acid ion exchange resin carrying aminothiol, and the process steps mainly comprise reaction, raw material recovery, crystallization purification, adduct decomposition, concentration and granulation. However, the above process causes cumylphenol as an impurity to be accumulated in the system, and chinese patent No. CN101370761A discloses a process for producing bisphenol a, in which a part of the mother liquor is extracted to be subjected to alkali cracking treatment in order to avoid accumulation of isomers or high boiling point impurities in the reaction system. The process for the preparation of bisphenol a disclosed in this patent comprises: a reaction step, a low boiling point component separation step, a bisphenol A separation step, a light component separation step and a recombination reaction step. In the patent, it is pointed out that the molar ratio of phenol to isopropenylphenol in the rearrangement reactor is 40 or more (about the total mass ratio of 28), and it is necessary to additionally supply phenol from the outside (for example, phenol used for washing crystals in the crystallization step), which increases energy consumption and material consumption. Meanwhile, the patent mentions that the rearrangement reaction temperature is preferably 50 to 85 ℃.

Chinese patent CN 104379546A discloses a method for preparing bisphenol A, which comprises the steps of separating solid and liquid after concentrated liquid crystals are precipitated after reaction, wherein at least one part of mother liquor is subjected to isomerization treatment, separating solid and liquid after the solution after the isomerization treatment is crystallized, and then cracking one part of the obtained mother liquor. However, this method requires the addition of an isomerization reactor and its auxiliary equipment.

Obviously, the above patents have at least the following problems: 1. the generated isopropyl phenol after cracking is directly returned to a condensation reaction system, so that the isopropyl phenol content in the reaction liquid is high, the activity of the catalyst is influenced, and the service life of the catalyst is shortened. 2. The heat generated after the light components of the recovered phenol are concentrated at high temperature is directly discharged and not fully utilized, so that the energy waste is caused. 3. The post-treatment process has more equipment and complex process.

Disclosure of Invention

The invention aims to provide an optimization method for a reaction system for preparing bisphenol A, which is characterized in that a mixture after condensation reaction is subjected to solid-liquid separation after concentrated liquid chromatography, wherein at least one part of mother liquor is subjected to isomerization reaction and rearrangement reaction simultaneously in an isomerization rearrangement reactor, so that the processes and equipment are reduced, the light component after the optimization process enters a phenol recovery system after the heat is recovered by an isomerization concentration tower, and isopropyl phenol which has a toxic effect on a catalyst is discharged along with mixed polyphenol, so that the amount of isopropyl phenol returned to the condensation reactor is reduced, and the service life of the catalyst in the condensation reactor is prolonged.

In order to achieve the purpose of the invention, the technical scheme of the invention is as follows:

an optimization method of a reaction system for preparing bisphenol A comprises the steps of sequentially carrying out isomerization reaction, concentration, partial preconcentration, cracking and rearrangement reaction on mother liquor (I) obtained by treating at least one part of reacted liquor; the reacted liquid is a mixed liquid obtained by condensation reaction of excessive phenol and acetone in a condensation reactor by a catalyst, and comprises bisphenol A, unreacted raw materials and a small amount of impurities; after the reaction system for preparing the bisphenol A operates, the isomerization reaction and the rearrangement reaction are simultaneously carried out in one isomerization rearrangement reactor to form a circulating operation system, and the isopropyl phenol generated in the cracking process enters a phenol recovery system along with light components in the partial pre-concentration process and is separated from phenol along with mixed polyphenol.

In the prior art, a reaction system for preparing bisphenol A generally comprises a main process system for catalytic reaction and a non-main process system for a mother liquor treatment process.

The main process system of the catalytic reaction completes the main process procedures, which mainly comprise condensation reaction, concentration of the reacted liquid, crystallization and solid-liquid separation procedures, and bisphenol A adduct and mother liquor (I) are separated; also comprises a step of processing the bisphenol A adduct to obtain a bisphenol A product. The non-main process system of the mother liquor treatment process is a post-treatment process of the mother liquor (I).

The purpose of the treatment in the non-main process is mainly to avoid accumulation of excessive isomers or high-boiling impurities in the reaction system in the main process. It is therefore common to remove the impurities contained by withdrawing a portion of the mother liquor (I) and returning the majority of the rest of the mother liquor (I) to the condensation reactor. The method for removing the impurities is a method for decomposing bisphenol A and isomers thereof into phenol and isopropenylphenol by an alkali cracking method, and then carrying out rearrangement reaction on the isopropenylphenol to obtain the bisphenol A. However, small amounts of cumene phenol are inevitably produced at the same time during the cracking process, and if the cumene phenol is returned directly to the condensation reactor, it has a poisoning effect on the catalyst in the condensation reactor, shortening the life of the catalyst. Therefore, the invention reduces equipment, reduces cost, simplifies process flow and saves energy consumption by optimizing the process of the reaction system for preparing the bisphenol A and combining reaction devices. On the other hand, the amount of cumene phenol fed to the condensation reactor is reduced to a reasonable level, extending the service life of the catalyst.

Specifically, the isomerization reaction and the rearrangement reaction are carried out in the same isomerization rearrangement reactor, because the catalysts used in the two reactions are strong-acid cation exchange resins, and the operating conditions of the two reactions are optimized and overlapped, so that the two reactions can be simultaneously carried out in the same reactor. On one hand, a large amount of unreacted phenol in the isomerization reaction feed can directly provide the needed excessive phenol for the rearrangement reaction, the problems that the rearrangement reaction phenol/isopropenylphenol has larger mole ratio and the original process needs to supply additional phenol are solved, and the operation is simplified; meanwhile, components capable of being isomerized in the impurities contained in the mother liquor are converted into the bisphenol A as much as possible on the premise of not increasing additional equipment, and the consumption of raw materials is reduced.

On the other hand, the technical scheme of the invention realizes the aim of the invention by optimizing the mother liquor treatment process. One part of the mother liquor (I) is directly returned to the condensation reactor, and the other part of the mother liquor is treated by a mother liquor treatment process to treat impurities in the mother liquor, and the unreacted phenol is recycled, and simultaneously, the isopropyl phenol which is generated in the mother liquor treatment process and has a toxic effect on a catalyst of the condensation reaction is reduced to a reasonable level.

Further, the reacted liquid is treated by a concentration process to obtain a concentrated liquid (I) and a light component (I), and the concentrated liquid (I) is treated by crystallization and solid-liquid separation processes to separate out a bisphenol A adduct and the mother liquor (I); the isomerization reaction procedure is to make at least a part of the mother liquor (I) in an isomerization rearrangement reactor; the concentration process is to carry out concentration process treatment on the product of the isomerization reaction to obtain a liquid-phase concentrated solution (II) and a gas-phase low-boiling-point component, and the concentrated solution (II) is crystallized and separated to obtain a solid-phase component and a mother liquor (II); the partial preconcentration process comprises the step of preconcentrating at least one part of the mother liquor (II) to obtain a heavy component (II) and a light component (II); the cracking procedure comprises the steps of adding alkali into the heavy component (II) for cracking to obtain a light component (III); the rearrangement reaction process comprises returning the condensed light component (III) to the isomerization rearrangement reactor for rearrangement reaction; after the bisphenol A reaction system operates, the rearrangement reaction and the isomerization reaction are simultaneously carried out in the isomerization rearrangement reactor, so that the equipment of the bisphenol A reaction system can be simplified, the equipment cost is saved, the reaction flow is simplified, and the operation procedure of the system after operation is simpler and more controllable.

Further, the concentration process and the light component (II) after partial pre-concentration are respectively concentrated and heat recovery by using the same isomerization concentration system; the product of the isomerization reaction is subjected to concentration process treatment in an isomerization concentration system; and returning the light component (II) to the isomerization concentration system, mixing the light component (II) with the low-boiling-point component in the isomerization concentration system, condensing and recovering heat, and then conveying the light component (II) to a phenol recovery system.

Through the technical scheme, the isomerization concentration system can concentrate the isomerization reaction product and recover the light component (II) and the low-boiling-point component in the same equipment, so that the arrangement of a pre-concentration rectifying tower condenser can be reduced, and the aim of simplifying the reaction system is fulfilled.

Further, at least one part of the mother liquor (II) returns to the isomerization rearrangement reactor, the other part of the mother liquor is subjected to preconcentration to obtain a heavy component (II), then the heavy component (II) is subjected to alkali cracking to obtain the light component (III) containing the isopropyl phenol, and the light component (III) is condensed and then returns to the isomerization rearrangement reactor to perform rearrangement reaction, so that the isopropenyl phenol is subjected to rearrangement reaction to obtain the bisphenol A.

Further, the mass ratio of the mother liquor (II) returning to the isomerization rearrangement reactor to enter the preconcentration tower is 0-10. When the reaction system just starts to operate, the impurities in the reaction system are extremely small, and the mother liquor (II) is completely rearranged. Along with the operation of the system for longer time, when the impurities in the reaction system are gradually accumulated, the impurity content is more and more, the mass ratio is larger and larger, and the mother liquor (II) returns to the isomerization rearrangement reactor and enters the preconcentration tower until the catalyst activity is gradually reduced to be not in accordance with the catalytic requirement, so that the mass ratio of the mother liquor (II) to the isomerization rearrangement reactor and the mother liquor (II) to the preconcentration tower is also the maximum value, and the catalyst needs to be replaced when the catalyst is inactivated.

Further, the phenol dehydration recovery system comprises a dehydration tower and a phenol refining tower; the light component (I) and the low-boiling point component are condensed and then sent to the dehydration tower; condensing the gas phase at the top of the tower, then feeding the gas phase into an acetone recovery tower to obtain recovered acetone, and performing oil-water separation on a product at the bottom of the tower to obtain an azeotropic agent mainly containing ethylbenzene, and recycling the azeotropic agent to the dehydration tower for use; the liquid phase at the tower bottom of the dehydrating tower enters a phenol refining tower, refined phenol is extracted from the gas phase at the tower top, and by-product mixed polyphenol is discharged from the tower bottom; and the fresh phenol raw material supplemented by the impurity removal reaction enters the dehydration tower and the phenol refining tower, and is dehydrated and refined and then is sent into the condensation reactor together with the refined phenol discharged from the gas phase at the top of the tower.

Further, the bisphenol A adduct is dephenolized in a liquid phase, phenol is removed to form a bisphenol A melt, and the melt is granulated to obtain a bisphenol A product.

Specifically, the method at least comprises the following steps:

at least comprises the following steps:

(1) a catalytic reaction process: under the action of a strong acid cation exchange resin catalyst, carrying out condensation reaction on excessive phenol and acetone to generate bisphenol A, and obtaining bisphenol A and a reaction solution of unreacted raw materials and a small amount of impurities; concentrating the reacted solution to obtain a concentrated solution (I) and a light component (I), and separating a bisphenol A adduct and a mother solution (I) from the concentrated solution (I) through crystallization and solid-liquid separation;

(2) an isomerization reaction step: at least one part of the mother liquor (I) obtained in the step (1) enters an isomerization rearrangement reactor for isomerization reaction, wherein the mass ratio of phenol to isopropenylphenol in the mother liquor (I) entering the isomerization rearrangement reactor is 30-1000:

(3) a concentration process: the product of the isomerization reaction enters an isomerization concentration system for concentration process treatment to obtain a liquid-phase concentrated solution (II) and a gas-phase low-boiling-point component;

(4) partial pre-concentration process: crystallizing the concentrated solution (II), and then carrying out solid-liquid separation to separate into a solid phase component and a mother solution (II); wherein at least a part of the solid phase component is diluted with the mother liquor (I) to prepare a crystallization liquid, and the crystallization liquid is returned to the step (1) to carry out crystallization and solid-liquid separation; at least a portion of said mother liquor (II) is recycled back to said isomerization rearrangement reactor; the other part is treated by a pre-concentration procedure to obtain a light component (II) and a heavy component (II);

(5) a cracking procedure: adding alkali into the heavy component (II) for cracking to obtain a gas-phase light component (III) containing isopropyl phenol;

(6) a rearrangement step: and (3) condensing the light component (III) through the isomerization concentration system, returning the light component (III) to the isomerization rearrangement reactor for rearrangement reaction, and enabling a concentrated product obtained by concentrating the rearranged product in the isomerization concentration system to be mixed with the concentrated solution (II) and the low-boiling-point components of the gas phase respectively to enter the step (4).

Further, the method comprises, in addition to the steps 1 to 6, a phenol recovery step (A): feeding at least a part of the light components obtained by concentration in the step (2) and the condensed products in the step (3) to a dehydration tower; the gas phase at the top of the tower enters an acetone recovery tower to obtain recovered acetone, and the product at the bottom of the tower is subjected to oil-water separation to obtain an entrainer mainly containing ethylbenzene, which is recycled to the dehydration tower for use; the liquid phase at the tower bottom of the dehydrating tower enters a phenol refining tower, refined phenol is extracted from the gas phase at the tower top, and by-product mixed polyphenol is discharged from the tower bottom;

(B) fresh phenol replenishing process: and the fresh phenol raw material supplemented by the impurity removal reaction returns to the dehydration tower and the phenol refining tower, and is sent into the condensation reactor together with the refined phenol discharged from the gas phase at the top of the tower after dehydration and refining.

Further, the mass percentage content of the isopropyl phenol in the condensation reactor in the bisphenol A reaction system is less than or equal to 0.25 percent.

Further, in the bisphenol A reaction system, the mass ratio of phenol to isopropenylphenol in the material entering the isomerization rearrangement reactor is 30-1000; the material comprises the mother liquor (I), the mother liquor (II) and a product obtained by condensing a light component (III) obtained in the cracking process.

In summary, the present invention adopts the above technical solutions to obtain the following technical effects:

1. by adopting the technical scheme of the invention, the cracking rearrangement product containing the isopropylphenol is subjected to a concentration process, so that the isopropylphenol enters a light component and is separated from heavy components such as bisphenol A, the light component enters a phenol recovery system, finally the isopropylphenol is discharged out of the system from the tower kettle of the phenol refining tower along with the mixed polyphenol, the isopropylphenol content in the phenol extracted from the tower top can be adjusted by means of adjusting the extraction amount of the tower kettle and the like, and the problem of the reduction of the service life of the catalyst caused by the fact that the cracking liquid or the rearrangement liquid which generates the isopropylphenol directly enters the reaction system in the prior art is solved.

2. By adopting the technical scheme of the invention, the content of phenol in the mixed polyphenol extracted from the bottom of the phenol tower is low, and the total extracted amount at the bottom of the phenol tower is small. And the phenol content in the phenol tower bottom extracted in the prior art is high, and heavy components at the tower bottom are discharged in the form of solid waste such as tar, so that the phenol raw material consumption is low, the solid waste is less, and the phenol tower is more environment-friendly.

3. By adopting the technical scheme of the invention, firstly, the gas phase at the top of the pre-concentration rectifying tower is sent into an isomerization product concentration system to be condensed together, so that the arrangement of a condenser of the pre-concentration rectifying tower can be reduced; secondly, the original dehydration tower is utilized to simultaneously complete the dehydration of the recovered phenol and the fresh phenol, so the operation can be simplified, the equipment is reduced, and the equipment investment is saved.

4. The technical scheme of the invention has the advantages of reducing energy consumption, and firstly, in the process of condensing the isomerization product and the rearrangement product after concentrating, hot water at about 90 ℃ can be generated by utilizing the latent heat of the isomerization product and the rearrangement product, and the hot water can be used for heating the reaction material entering the reactor, so that the heat can be fully utilized. And secondly, the gas phase at the top of the phenol tower is used as a heat source of a steam generator, hot water is converted into low-pressure steam while the phenol gas phase is condensed, the low-pressure steam is used by other equipment which needs the low-pressure steam as a heating medium, after heat balance, the low-pressure steam is not required to be additionally provided, the low-pressure steam generated at the top of the phenol refining tower can meet the requirement, and the process can greatly reduce the energy consumption of the device.

Drawings

FIG. 1 is a schematic process flow diagram of example 1 of the present invention.

Fig. 2 is a schematic view of a connection structure of the device according to embodiment 1 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention are clearly and completely described below with reference to the specific contents of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.

The reaction system for preparing bisphenol A generally comprises a catalytic reaction system and a mother liquor treatment process system.

The catalytic reaction system completes the main process procedure which mainly comprises condensation reaction, concentration of the reacted liquid, crystallization and solid-liquid separation procedures, and bisphenol A adduct and mother liquor are separated; also comprises a step of processing the bisphenol A adduct to obtain a bisphenol A product. The mother liquor treatment step is a post-treatment step of the mother liquor (I).

The technical scheme of the invention realizes the aim of the invention by optimizing the mother liquor treatment process. Specifically, a part of mother liquor obtained by concentrating, crystallizing and carrying out solid-liquid separation on a reaction solution of the condensation reaction is directly returned to the condensation reactor, the other part of the mother liquor is subjected to a mother liquor treatment process to treat impurities in the mother liquor, unreacted phenol is recycled, and meanwhile, the isopropyl phenol which is generated in the mother liquor treatment process and has a toxic effect on a catalyst of the condensation reaction is reduced to a reasonable level. Through the technical scheme, the rearrangement reaction and the isomerization reaction are combined, and meanwhile, the light component enters the phenol recovery system after being subjected to heat recovery through the isomerization concentration tower, the number of equipment investment is reduced, and the operation process is simplified.

Meanwhile, the amount of the isopropyl phenol returned to the condensation reactor can be reduced, so that the poison of the condensation reactor on the catalyst is reduced, and the service life of the catalyst is prolonged.

The technical solution of the present invention is further illustrated by the following specific examples.

Example 1:

this example specifically includes the following steps (1) to (10) with reference to fig. 1 and 2.

Step (1) catalytic reaction step

Excessive phenol or recovered phenol is heated to a proper temperature and then mixed with acetone according to a certain proportion, and the mixture and part of mother liquor (I) after crystallization and solid-liquid separation in the subsequent process enter a condensation reactor together, a strong acid cation resin transfer catalyst is filled in the condensation reactor, and the phenol and the acetone are subjected to condensation reaction in the condensation reactor to generate bisphenol A (BPA), water and a small amount of impurities. The impurities mainly comprise: 2,4-BPA isomers, methyl BPA, triphenol, color-hidden, isopropylphenol dimer, and the like.

In the step (1), the condensation reactor is operated at 55 to 85 ℃ and at 0.2 to 0.4MPa (gauge pressure).

Because the isopropyl phenol is generated in the subsequent cracking process in the cracking reactor, the isopropyl phenol finally enters the subsequent phenol refining tower, a small part of the isopropyl phenol exists in the recovered phenol at the top of the tower, and most of the isopropyl phenol is discharged out of the system along with the mixed polyphenol at the bottom of the phenol refining tower. The amount of cumene phenol is an important factor affecting the life of the reactor catalyst, and therefore the amount of cumene phenol in the condensation reactor can be controlled by controlling the amount of cumene phenol in the recovered phenol, in this example, the amount of cumene phenol in the reaction solution is controlled to be less than 0.21 wt%.

Step (2) crystallization and solid-liquid separation treatment step

This step is carried out in a lightness-removing column.

This procedure separates water, part of the by-products, part of the unreacted excess phenol and crude bisphenol A.

Specifically, the reverse solution enters the middle part of a light component removal tower after heat exchange through a heat exchanger, the reverse solution is rectified and concentrated to obtain a concentrated solution (I) and a light component (I), and the separated light component (I) is sent to a dehydration tower; the material in the tower bottom is crude bisphenol A, and mainly contains phenol, bisphenol A and impurities.

The operating pressure of the light component removal tower is-0.1 to 0.1MPa (gauge pressure), and in order to reduce the operating temperature, vacuum operation is preferably adopted.

And (3) feeding the concentrated solution (I) in the light component removal tower into a crystallizer for crystallization to generate a crystal of the bisphenol A adduct and a liquid phase for washing the crystal, and then carrying out solid-liquid separation on the crystal and the liquid phase. The operation processes of crystallization, washing and solid-liquid separation are repeated for at least 3 times; washing the bisphenol A crystal washed for the last time by using phenol, and then carrying out solid-liquid separation by using a centrifugal machine to obtain a purer bisphenol A adduct finally, and collecting the liquid phase of the solid-liquid separation to obtain a mother liquor (I); wherein one part of the mother liquor (I) returns to the working procedure (1) for reuse, and the other part enters into the isomerization working procedure.

The filter cake of the crystal (adduct of phenol and bisphenol A) obtained by centrifugal separation is sent to a melting tank to be heated and heated to be melted and then enters the working procedure (3).

Step (3) production of bisphenol A product

Evaporating and stripping the phenol from the mixture of the molten phenol and the bisphenol A under vacuum and at a higher temperature to produce the bisphenol A with high purity, forming a bisphenol A molten liquid, and granulating the molten liquid to obtain the bisphenol A product.

The liquid phase dephenolizing equipment in the working procedure (3) adopts two-stage or multi-stage falling film evaporator, steam stripping tower and other combined equipment, the operating temperature of the falling film evaporator is 170-190 ℃, and the operating pressure is-0.1-E

The gauge pressure is-0.02 MPa, the operating temperature of the steam stripping tower is 170-200 ℃, and the operating pressure is-0.1-0.05 MPa.

Step (4) isomerization reaction step

At least a part of the mother liquor (I) obtained in the step (2) enters an isomerization rearrangement reactor to carry out isomerization reaction.

Step (5): concentration step

And (3) introducing the product of the isomerization reaction into an isomerization concentration system for concentration process treatment to obtain a liquid-phase concentrated solution (II) and a gas-phase low-boiling-point component. After the low boiling point components are condensed and the heat is recovered, the product is sent to a phenol recovery system.

The isomerization concentration system comprises a hot water generator and a flash tank, the isomerization product is concentrated in the flash tank, then the light component obtained by gas-liquid separation is recycled in the hot water generator together with other light components and low boiling point components to generate hot water at about 90 ℃, and the hot water can be used for heating reaction materials entering the condensation reactor, so that the heat is fully utilized, and the effective utilization rate of energy is improved.

In order to simultaneously meet the reaction conditions of the isomerization reaction and the subsequent rearrangement reaction, the operating temperature of the reactor is 53-90 ℃, and the operating pressure is normal pressure or micro-positive pressure.

Step (6): partial preconcentration process

Crystallizing the concentrated solution (II) obtained in the step (5), and then performing solid-liquid separation to separate the concentrated solution into a solid component and a mother liquor (II); wherein the solid phase component is diluted with at least a part of the mother liquor (I) produced in the step (2), and then fed into the crystallization system in the main flow of the step (2) for crystallization and solid-liquid separation; and (3) at least one part of the obtained mother liquor (II) enters a pre-concentration tower to be subjected to pre-concentration process treatment to obtain a light component (II) and a heavy component (II), the light component (II) enters an isomerization concentration system of the process (5), and is condensed together with the low-boiling-point components of the process (5) by virtue of the isomerization concentration system, and heat is recovered. The other part of the mother liquor (II) is recycled to the isomerization rearrangement reactor.

Preferably, the mass ratio of the mother liquor (II) returned to the isomerization rearrangement reactor to the pre-concentration tower is 0-5, preferably 0.2-5. When the reaction system is just started to operate, the amount of impurities in the reaction system is very small or even zero, and the mother liquor (II) is completely rearranged. When the reaction system just starts to operate, the impurities in the reaction system are extremely small, and the mother liquor (II) is completely rearranged. Along with the operation of the system for longer time, when the impurities in the reaction system are gradually accumulated, the impurity content is more and more, the mass ratio is larger and larger, and the mother liquor (II) returns to the isomerization rearrangement reactor and enters the preconcentration tower until the catalyst activity is gradually reduced to be not in accordance with the catalytic requirement, so that the mass ratio of the mother liquor (II) to the isomerization rearrangement reactor and the mother liquor (II) to the preconcentration tower is also the maximum value, and the catalyst needs to be replaced when the catalyst is inactivated.

The operation temperature of the pre-concentration tower is 110-180 ℃, and the operation pressure is-0.1-0.02 MPa (gauge pressure).

In the step of the embodiment of the invention, the isomerization reactor and the rearrangement reactor are combined into the isomerization rearrangement reactor, and part of the preconcentration process and the concentration process share one isomerization concentration system, so that the process flow is simplified, and the energy consumption is saved; the feeding material of the isomerization rearrangement reactor contains a large amount of unreacted phenol, the mass ratio of the phenol to the isopropenylphenol in the feeding material is 150-500, the required excessive phenol can be provided for the rearrangement reaction, and the molar ratio of the phenol to the isopropenylphenol in the rearrangement reaction is ensured, so that the rearrangement reaction is favorably carried out.

Step (7) cracking step

And (3) introducing the heavy component (II) after partial preconcentration in the step (6) into a cracking reactor for alkali addition cracking to generate a gas-phase light component (III). The cracking process decomposes bisphenol a and its isomers into phenol and isopropenylphenol, and a small amount of isopropylphenol. The isopropyl phenol enters the light fraction (III).

Wherein the operation temperature of the cracking reactor is 170-215 ℃, and preferably 180-210 ℃.

Step (8) rearrangement reaction step

Condensing the light component (III) generated in the cracking procedure through the isomerization concentration system, recovering heat, then entering an isomerization rearrangement reactor in the procedure (4) for rearrangement reaction, and carrying out rearrangement reaction on isopropenylphenol to obtain the bisphenol A.

And (3) enabling the rearrangement product to enter an isomerization concentration system, and mixing the concentrated product obtained by concentration with the concentrated solution (II) and the gas-phase low-boiling-point component respectively to enter a part of pre-concentration process in the step (6).

Step (9) phenol recovery step

Feeding at least a part of the light component (I) obtained by concentration in the step (2) and the condensed product of the light component (II) in the partial preconcentration step to a dehydration column; directly feeding the gas phase at the top of the dehydrating tower into an acetone recovery tower, rectifying and separating the gas phase at the top of the dehydrating tower to obtain recovered acetone, and performing oil-water separation on the product at the bottom of the dehydrating tower to obtain an entrainer which is recycled to the dehydrating tower for use; the liquid phase at the tower bottom of the dehydration tower enters a phenol refining tower, refined phenol is extracted from the gas phase at the tower top, and mixed polyphenol containing isopropyl phenol is extracted from the tower bottom;

the content of isopropyl phenol in the mixed polyphenol in the phenol refining tower kettle is controlled to be 10-30 percent (mass content); the cumene phenol in the phenol recovered from the top of the tower can be controlled at 100-300ppm (mass content) by regulating the extraction amount at the bottom of the tower.

In the embodiment, a circulating operation system is formed after the reaction system operates, the cracked light component (iii) containing the isopropyl phenol is returned to the isomerization rearrangement reactor, the rearrangement product is subjected to a concentration process, the isopropyl phenol enters the light component through a preconcentration process, the isopropyl phenol is separated from the heavy components such as bisphenol a, the light component enters the phenol recovery system, and the light component is discharged out of the system from the tower kettle of the phenol refining tower along with the mixed polyphenol.

The gas phase at the top of the phenol tower is used as a heat source of a steam generator, hot water is converted into low-pressure steam while the phenol gas phase is condensed, the low-pressure steam is used by other equipment which needs the low-pressure steam as a heating medium, after heat balance, the low-pressure steam is not required to be additionally provided by the invention, the low-pressure steam generated at the top of the phenol refining tower can meet the requirement, and the process can greatly reduce the energy consumption of the device.

Step (10) phenol replenishment step

And feeding the fresh phenol subjected to impurity removal reaction into a dehydration tower in a phenol dehydration recovery process.

The operating temperature of the dehydration tower is 110-230 ℃, and the operating pressure is 0.01-0.4 MPa (gauge pressure); the dehydration tower is azeotropic distillation, and the selected azeotropic agent can be a chemical such as toluene or ethylbenzene and the like which can form an azeotrope with water, and preferably ethylbenzene.

After the processes 1-10 are sequentially performed, the bisphenol A reaction system starts to operate, the processes start to operate circularly, the isomerization reaction and the rearrangement reaction are performed simultaneously in the isomerization rearrangement reactor, and the light component is the isopropylphenol mass percentage content in the condensation reactor in the bisphenol A reaction system

≤0.25％。

The purity of the bisphenol A product finally obtained in the embodiment is more than or equal to 99.93 percent (mass percent), the freezing point is 156.7-156.8 ℃, the phenol content is 20ppm (mass content), the water content is 500ppm (mass content), and the ash content is 1ppm (mass content).

Example 2:

the embodiment provides an optimization method of a bisphenol A reaction system, which comprises the following specific steps:

step (1) catalytic reaction step

Under the action of a strong acid cation exchange resin catalyst, excessive phenol of 12.6kg/h and acetone of 4.0kg/h and the mother liquor of 51.4kg/h of subsequent crystallization solid-liquid separation are mixed and then enter a condensation reactor for condensation reaction to generate bisphenol A, and the reaction liquid of the bisphenol A adduct, unreacted raw materials and a small amount of impurities is obtained.

Step (2) crystallization and solid-liquid separation treatment step, concentrating the reverse solution obtained in step (1) to obtain a concentrated solution (I) and a light component (I), wherein the light component (I) is delivered to a dehydration tower at 8.2kg/h, and the light component (I) mainly comprises the following components in percentage by mass: 11.3% of acetone, 32.5% of water and 56.1% of phenol; the bisphenol A content in the obtained concentrated solution (I) is 24 percent (mass percent).

Crystallizing the concentrated solution to generate a crystal of the bisphenol A adduct, cleaning and filtering the crystal, and repeating the processes of crystallizing, cleaning and filtering for 3-4 times; the crystallization solid-liquid separation process can obtain purer bisphenol A adduct and mother liquor (I); wherein at least a part of the mother liquor (I) is returned to the step (1).

Step (3) production of bisphenol A product

The bisphenol A adduct obtained in the step (2) was dephenolized in a liquid phase to remove phenol, thereby forming a bisphenol A melt, and the melt was granulated to obtain 7.6kg/h of a bisphenol A product.

Step (4) isomerization reaction step

A part of 8.97kg/h of the mother liquor (I) obtained in the step (2) was fed into an isomerization rearrangement reactor, and was subjected to an isomerization reaction together with 5.79kg/h of the light fraction (III) cracked in the subsequent step (7).

Step (5) concentration step

And (3) feeding the product of the isomerization reaction into an isomerization concentration system for concentration to obtain a liquid-phase concentrated solution (II) and a gas-phase low-boiling-point component, wherein the low-boiling-point component is 7.76 kg/h.

The gas phase low boiling point component is condensed and heat is recovered, and then the gas phase low boiling point component is sent into a phenol recovery system and is subjected to heat to generate hot water for heating reaction materials in the condensation reactor.

Step (6) partial preconcentration step

Crystallizing 7.7kg/h of the concentrated solution (II), and then carrying out solid-liquid separation to separate into a solid component and a mother solution (II); wherein 4.2kg/h of the solid phase component is diluted with at least a part of the mother liquor (I) produced in the step (2), and then the diluted solid phase component is fed to the step (2) of the main reaction flow for crystallization and solid-liquid separation treatment; in the obtained mother liquor (II), 2.8kg/h (II) is subjected to pre-concentration process treatment, 0.7kg/h of the mother liquor (II) returns to the working procedure (4) and enters an isomerization rearrangement reactor, a light component (II) and a heavy component (II) are obtained after pre-concentration, 0.46kg/h of the light component (II) enters an isomerization concentration system of the working procedure (5), and the light component (II) and the gas phase low boiling point component of the working procedure (5) are condensed together by means of the isomerization concentration system.

That is, in the partial preconcentration step, at least a part of 2.8 kg/hr of the mother liquor (II) obtained by solid-liquid separation was preconcentrated, and a part of 0.7 kg/hr thereof was returned to the isomerization rearrangement reactor of the step (4). The mass ratio of the mother liquor (II) returned to the isomerization rearrangement reactor and fed into the preconcentration tower is 0.25.

Step (7) cracking step

And (4) carrying out alkaline cracking on the heavy component (II) concentrated in the step (6) in a cracking reactor, and cracking to obtain a light component (III).

Step (8) rearrangement reaction step

The light component (III) is condensed at 5.79kg/h and then enters an isomerization rearrangement reactor in the working procedure (4) for rearrangement reaction. Wherein the content of isopropylphenol in the feed of the isomerization rearrangement reactor is 0.24 percent (mass percent), and the mass ratio of phenol to isopropenylphenol is 200-500. The heavy component obtained by cracking is 0.22kg/h, and the components are mixed polyphenol such as triphenol, polyphenol and the like.

In the embodiment, the reaction system forms a circulating operation system, the cracked light component (iii) containing the isopropylphenol is returned to the isomerization rearrangement reactor, the rearrangement product is subjected to a concentration process, the isopropylphenol enters the light component through a preconcentration process, the isopropylphenol is separated from the heavy components such as the bisphenol a and the like, the light component enters the phenol recovery system, and finally the light component is discharged out of the system along with the mixed polyphenol from the tower kettle of the phenol refining tower, so that the problem that the cracked liquid or the rearrangement liquid containing the isopropylphenol directly enters the reactor of the bisphenol a reaction system, the content of the isopropylphenol in the reaction liquid is controlled to be below 0.21 wt% (mass percentage), and the service life of the condensation reaction catalyst can be prolonged by 10% compared with the prior art under the condition of low isopropylphenol concentration.

Step (9) phenol recovery step:

the phenol recovery process comprises a dehydration column and a phenol purification column.

8.2kg/h of light component (I) obtained by concentration in the step (2) and 4.55kg/h of condensation product obtained by mixing the light component (II) and the low-boiling point component in the step (6) are sent into a dehydration tower; the gas phase at the top of the tower enters an acetone recovery tower to obtain 0.95kg/h of recovered acetone with the purity of 99.96 percent (mass percent), and the product at the bottom of the tower is subjected to oil-water separation to obtain an entrainer mainly containing ethylbenzene and is recycled to the dehydration tower for use; the liquid phase at the tower bottom of the dehydration tower enters a phenol refining tower, 24.389kg/h of refined phenol is extracted from the gas phase at the tower top, and 0.011kg/h of mixed polyphenol is discharged from the tower bottom. The isopropyl phenol content in the final phenol refined phenol obtained at the top of the phenol refining column was 260ppm (mass content), and the phenol purity was 99.96% (mass percentage); the content of isopropylphenol in the mixed polyphenol at the bottom of the tower is 20 percent (mass content).

Step (10)

12.6kg/h of fresh phenol which has undergone impurity removal reaction and which only contains a very small amount of isopropylphenol is fed into a dehydration column of a phenol recovery process and finally returned to the condensation reactor.

In this example, after the reaction system was operated, the content of isopropylphenol in the condensation reactor was 0.21% (by mass)

The final bisphenol A product of this example had a purity of 99.93% or more (by mass), a phenol content of 20ppm (by mass), a moisture content of 500ppm (by mass), and an ash content of 1ppm (by mass).

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. An optimization method of a reaction system for preparing bisphenol A is characterized in that mother liquor (I) obtained by treating at least a part of reacted liquor is subjected to isomerization reaction, concentration, partial preconcentration, cracking and rearrangement reaction in sequence; the reacted liquid is a mixed liquid obtained by condensation reaction of excessive phenol and acetone in a condensation reactor by a catalyst, and comprises bisphenol A, unreacted raw materials and a small amount of impurities;

after the reaction system for preparing the bisphenol A operates, the isomerization reaction and the rearrangement reaction are simultaneously carried out in one isomerization rearrangement reactor to form a circulating operation system, and the isopropyl phenol generated in the cracking process enters a phenol recovery system along with light components in the partial pre-concentration process and is separated from phenol along with mixed polyphenol.

2. The method for optimizing a reaction system for producing bisphenol a according to claim 1, wherein:

treating the reacted solution by a concentration process to obtain a concentrated solution (I) and a light component (I), and treating the concentrated solution (I) by crystallization and solid-liquid separation processes to separate out a bisphenol A adduct and the mother solution (I);

the isomerization reaction procedure is to make at least a part of the mother liquor (I) in an isomerization rearrangement reactor;

the concentration process is to carry out concentration process treatment on the product of the isomerization reaction to obtain a liquid-phase concentrated solution (II) and a gas-phase low-boiling-point component, and the concentrated solution (II) is crystallized and separated to obtain a solid-phase component and a mother liquor (II);

the partial preconcentration process comprises the step of preconcentrating at least one part of the mother liquor (II) to obtain a heavy component (II) and a light component (II);

the cracking procedure comprises the steps of adding alkali into the heavy component (II) for cracking to obtain a light component (III);

the rearrangement reaction process comprises returning the condensed light component (III) to the isomerization rearrangement reactor for rearrangement reaction.

3. The method for optimizing a reaction system for producing bisphenol a according to claim 2, wherein:

the concentration step and the light component (II) after partial pre-concentration are respectively concentrated and heat recovery by using the same isomerization concentration system;

the product of the isomerization reaction is subjected to a concentration process in the isomerization concentration system; and returning the light component (II) to the isomerization concentration system, mixing the light component (II) with the low-boiling-point component in the isomerization concentration system, condensing and recovering heat, and then conveying the light component (II) to a phenol recovery system.

4. The method for optimizing a reaction system for producing bisphenol a according to claim 2, wherein: at least one part of the mother liquor (II) returns to the isomerization rearrangement reactor, the other part of the mother liquor (II) is subjected to preconcentration to obtain a heavy component (II), then the heavy component (II) is subjected to alkali addition cracking to obtain the light component (III) containing the isopropyl phenol, and the light component (III) is condensed and then returns to the isomerization rearrangement reactor for rearrangement reaction.

5. The method for optimizing a reaction system for producing bisphenol a according to claim 4, wherein: and the mass ratio of the mother liquor (II) returning to the isomerization rearrangement reactor to the mother liquor entering the preconcentration tower is 0-10.

6. The method for optimizing a reaction system for producing bisphenol A according to any of claims 2 to 5, wherein: the phenol recovery system comprises a dehydration tower and a phenol refining tower; at least one part of the light component (I) and the low-boiling component is sent to the dehydration tower after being condensed; the gas phase at the top of the tower enters an acetone recovery tower to obtain recovered acetone, and the product at the bottom of the tower is subjected to oil-water separation to obtain an entrainer mainly containing ethylbenzene, which is recycled to the dehydration tower for use; the liquid phase in the tower bottom of the dehydration tower enters a phenol refining tower, the refined phenol is extracted from the gas phase at the tower top, and the byproduct mixed polyphenol is discharged from the tower bottom; and the fresh phenol raw material supplemented by the impurity removal reaction enters the dehydration tower and the phenol refining tower, and is dehydrated and refined and then is sent into the condensation reactor together with the refined phenol discharged from the gas phase at the top of the tower.

7. The method for optimizing a reaction system for producing bisphenol A according to any of claims 1 to 5, wherein: and carrying out liquid phase dephenolization on the bisphenol A adduct, removing phenol to form bisphenol A molten liquid, and granulating the molten liquid to obtain the bisphenol A product.

8. The method for optimizing a reaction system for producing bisphenol A according to any of claims 1 to 7, wherein: at least comprises the following steps:

(1) a catalytic reaction process: under the action of a strong acid cation exchange resin catalyst, carrying out condensation reaction on excessive phenol and acetone to obtain bisphenol A and a reaction solution of unreacted raw materials and a small amount of impurities; concentrating the reacted solution to obtain a concentrated solution (I) and a light component (I), and separating a bisphenol A adduct and a mother solution (I) from the concentrated solution (I) through crystallization and solid-liquid separation;

(2) an isomerization reaction step: at least one part of the mother liquor (I) obtained in the step (1) enters an isomerization rearrangement reactor to carry out isomerization reaction:

(3) a concentration process: the product of the isomerization reaction enters an isomerization concentration system for concentration process treatment to obtain a liquid-phase concentrated solution (II) and a gas-phase low-boiling-point component;

(4) partial pre-concentration process: crystallizing the concentrated solution (II), and then carrying out solid-liquid separation to separate into a solid phase component and a mother solution (II); wherein at least a part of the solid phase component is diluted with the mother liquor (I) to prepare a crystallization liquid, and the crystallization liquid is returned to the step (1) to carry out crystallization and solid-liquid separation; at least a portion of said mother liquor (II) is recycled back to said isomerization rearrangement reactor; the other part enters a pre-concentration tower to be subjected to pre-concentration process treatment to obtain a light component (II) and a heavy component (II);

(5) a cracking procedure: adding alkali into the heavy component (II) for cracking to obtain a gas-phase light component (III); adding isopropyl phenol generated by alkaline cracking into the light component (III);

(6) a rearrangement step: and (3) condensing the light component (III) through the isomerization concentration system, returning the light component (III) to the isomerization rearrangement reactor for rearrangement reaction, and enabling a concentrated product obtained by concentrating the rearranged product in the isomerization concentration system to be mixed with the concentrated solution (II) and the low-boiling-point components of the gas phase respectively to enter the step (4).

9. The method for optimizing a reaction system for producing bisphenol a as recited in claim 8, wherein: after the bisphenol A reaction system operates, the mass percentage content of the isopropyl phenol in the condensation reactor is less than or equal to 0.25 percent.

10. The method for optimizing a reaction system for producing bisphenol a as recited in claim 8, wherein: in the bisphenol A reaction system, the mass ratio of phenol to isopropenylphenol in the material entering the isomerization rearrangement reactor is 30-1000; the material comprises the mother liquor (I), the mother liquor (II) and a product obtained by condensing a light component (III) obtained in the cracking process.

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