阅读说明：本技术 一种苯酚连续采出系统、包括其的聚碳酸酯树脂生产系统及生产方法 (Phenol continuous extraction system, polycarbonate resin production system comprising phenol continuous extraction system and production method ) 是由 徐菲 张锁江 杨子锋 赵秋 张振才 周志茂 张军平 于 2019-10-11 设计创作，主要内容包括：本发明提供了一种苯酚连续采出系统、包括其的聚碳酸酯树脂生产系统及生产方法,所述的苯酚连续采出装置包括连通的气液分离装置和苯酚收集装置,所述的气液分离装置用于调节进入气液分离装置内的气液混合物的流速,所述的苯酚收集装置内纵向设置有至少一个折流挡板。本发明提供的苯酚连续采出系统可以确保聚碳酸酯树脂生产系统内部真空度和密封性的同时,对副产物苯酚实现连续采出,同时,对采出后的苯酚进行了有效的回收利用。(the invention provides a phenol continuous extraction system, a polycarbonate resin production system comprising the same and a production method, wherein the phenol continuous extraction device comprises a gas-liquid separation device and a phenol collection device which are communicated, the gas-liquid separation device is used for adjusting the flow rate of a gas-liquid mixture entering the gas-liquid separation device, and at least one baffling baffle is longitudinally arranged in the phenol collection device. The continuous phenol extraction system provided by the invention can ensure the internal vacuum degree and the sealing property of the polycarbonate resin production system, simultaneously realize continuous extraction of the byproduct phenol, and simultaneously effectively recycle the extracted phenol.)

1. the continuous phenol extraction system is characterized in that the continuous phenol extraction device comprises a gas-liquid separation device and a phenol collection device which are communicated, the gas-liquid separation device is used for adjusting the flow rate of a gas-liquid mixture entering the gas-liquid separation device, and at least one baffle is longitudinally arranged in the phenol collection device.

2. The continuous phenol extraction system according to claim 1, wherein the gas-liquid separation device comprises a separation device shell, the separation device shell is provided with a feed inlet, an exhaust outlet and a liquid outlet, a reaction product generated by the upstream production system enters the gas-liquid separation device through the feed inlet to be subjected to gas-liquid separation, gas is discharged through the exhaust outlet, and liquid enters the phenol collection device through the liquid outlet;

Preferably, the liquid outlet is connected with a liquid discharge pipeline, the phenol collecting device is filled with cleaning liquid, and the outlet end of the liquid discharge pipeline extends below the liquid level of the cleaning liquid;

preferably, the cleaning solution comprises phenol;

Preferably, the exhaust port is externally connected with a vacuum pumping device;

preferably, a separation cavity is formed inside the shell of the separation device, and the separation cavity is used for reducing the flow velocity of the gas-liquid mixture entering the gas-liquid separation device;

Preferably, the diameter of the cavity of the separation cavity is larger than the caliber of the feeding hole;

Preferably, the ratio of the cavity diameter of the separation cavity to the caliber of the feed inlet is (10-50): 1.

3. The phenol continuous production system according to claim 1 or 2, wherein the baffle plate is divided into an upper plate and a lower plate;

Preferably, the upper baffle is longitudinally fixed on the top surface of the phenol collecting device;

preferably, the lower baffle is longitudinally fixed on the bottom surface of the phenol collecting device;

Preferably, the upper baffle and the lower baffle are arranged in a staggered manner.

4. the continuous phenol recovery system according to any one of claims 1 to 3, wherein the housing of the phenol collection device is provided with a filling port, a vacuum pumping port, an overflow port and a drain port;

Preferably, a cleaning solution is injected into the phenol collecting device through the liquid adding port;

Preferably, the vacuumizing port is externally connected with a vacuumizing device;

Preferably, the overflow port is externally connected with an overflow pipeline;

Preferably, the evacuation port is externally connected with an evacuation pipeline;

preferably, an emptying valve is arranged on the emptying pipeline;

preferably, the outlet end of the overflow pipeline is connected to an emptying pipeline, and the liquid level in the phenol collecting device is discharged from the emptying pipeline through the overflow pipeline when reaching the height of an overflow port;

Preferably, a heating device is arranged at the bottom of the phenol collecting device;

Preferably, the bottom of the phenol collecting device is further provided with a cleaning opening, the cleaning opening is located between the adjacent lower baffle and the upper baffle, and the cleaning opening is externally connected with a cleaning medium pipeline.

5. a polycarbonate resin production system is characterized by comprising a reaction unit, a phenol extraction unit and a granulation unit, wherein the phenol extraction unit and the granulation unit are respectively connected with the reaction unit;

The phenol production unit includes the phenol continuous production system according to any one of claims 1 to 4.

6. The polycarbonate resin production system of claim 5, wherein the reaction unit comprises a transesterification reaction apparatus and a final polycondensation reaction apparatus connected in series according to a polycarbonate production process route;

Preferably, the granulation unit comprises a mixing device, a filtering device and an extrusion granulation device which are connected in sequence;

preferably, the extrusion granulation device is a double-screw extruder;

preferably, the final polycondensation reaction device is connected with a gas-liquid separation device through a phenol extraction pipeline;

Preferably, the outlet end of the phenol extraction pipeline extends into the gas-liquid separation device through a feed inlet formed in the top of the gas-liquid separation device;

preferably, the final polycondensation reaction device is connected with the mixing device through a discharge pipeline;

Preferably, a discharge valve is arranged on the discharge pipeline.

7. The polycarbonate resin production system of claim 5 or 6, wherein a flushing pipeline is connected to the bottom of the phenol collection device, the outlet end of the flushing pipeline is connected to a discharge pipeline, and phenol collected by the phenol collection device is discharged into the discharge pipeline through the flushing pipeline as a cleaning solution to clean the final polycondensation reaction device and the mixing device;

Preferably, a pressurizing device is arranged on the flushing pipeline;

preferably, the filtering device is connected with the phenol collecting device through a waste liquid return pipeline, and waste liquid obtained by filtering of the filtering device is recycled to the phenol collecting device through the waste liquid return pipeline for replenishing consumed cleaning liquid;

preferably, a pressure boosting device is arranged on the waste liquid return pipeline.

8. a method for producing a polycarbonate resin, characterized in that the production method is carried out in the polycarbonate resin production system according to any one of claims 5 to 7;

The production method comprises the following steps:

The production raw materials are subjected to esterification reaction and polycondensation reaction in a reaction unit to obtain a polycarbonate melt and a byproduct;

(II) continuously extracting the by-product discharged in the step (I) through a phenol extraction unit;

(III) extruding and granulating the polycarbonate melt obtained in the step (I) in a granulating unit to obtain the polycarbonate resin.

9. The method for producing a polycarbonate resin according to claim 8, wherein the production raw materials of step (i) include a reaction raw material and a catalyst;

preferably, the reaction raw materials comprise diphenyl carbonate and a dihydroxy compound;

preferably, the catalyst comprises one or a combination of at least two of basic ionic liquid, alkali metal or alkaline earth metal compounds;

Preferably, the esterification reaction is carried out in a transesterification reaction device;

preferably, the esterification reaction is carried out under a nitrogen atmosphere;

Preferably, the reaction temperature of the esterification reaction is 80-180 ℃;

Preferably, the reaction time of the esterification reaction is 0.1-6 h;

Preferably, the polycondensation reaction is carried out in a final polycondensation reaction device;

Preferably, the reaction temperature of the polycondensation reaction is 180-300 ℃;

Preferably, the reaction time of the polycondensation reaction is 0.1-6 h;

preferably, the polycondensation reaction is carried out under a nitrogen atmosphere.

10. the method for producing a polycarbonate resin according to claim 8 or 9, wherein the by-products of step (ii) include phenol, alcohols and water vapor;

Preferably, the continuous production process of step (ii) comprises:

The flow rate of the by-product is reduced after the by-product enters the gas-liquid separation device, the gas is exhausted outwards from the exhaust port of the gas-liquid separation device, so that the inside of the gas-liquid separation device is kept in a negative pressure state, meanwhile, the vacuum degree in the phenol collection device is kept consistent with the vacuum degree in the gas-liquid separation device by exhausting outwards from the vacuumizing port of the phenol collection device, water vapor and alcohols in the by-product are exhausted from the exhaust port under the action of negative pressure, and the phenol enters the phenol collection device through a liquid discharge pipeline to be recovered;

Preferably, step (ii) further comprises:

(1) Using phenol recovered by a phenol collecting device as a cleaning solution to clean the final polycondensation reaction device and the mixing device;

(2) after the reaction is finished, stopping extracting the by-product, introducing a cleaning medium into the phenol collecting device through a cleaning opening, and cleaning the bottom of the phenol collecting device;

Preferably, the cleaning medium is steam;

Preferably, the extrusion granulation process of step (iii) comprises:

mixing the polycarbonate melt with the auxiliary agent in the mixing device, introducing the mixture into a filtering device, and extruding and granulating the filtered polycarbonate melt by an extruding and granulating device;

Preferably, the waste liquid filtered by the filtering device is returned to the phenol collecting device to be used as a cleaning liquid to replenish the cleaning liquid consumed in the cleaning process.

Technical Field

the invention belongs to the field of polycarbonate production, and relates to a phenol continuous extraction system, a polycarbonate resin production system comprising the same and a production method, in particular to a phenol continuous extraction system adopting gas-liquid separation, a polycarbonate resin production system comprising the same and a production method.

background

The transesterification polycarbonate is also called melt polycarbonate, and utilizes the melt polycondensation of diol compounds such as bisphenol A, isosorbide and the like and diphenyl carbonate to perform transesterification, continuously discharges phenol under the conditions of high temperature and reduced pressure and improves the reaction degree and the molecular weight. The reaction raw material has high purity requirement, low reaction speed, complex reactor structure and high tightness requirement.

The preparation process of the polycarbonate by the ester exchange method comprises an esterification process and a polycondensation process, wherein diphenyl carbonate is excessive at the initial stage of the reaction, phenol is discharged through the ester exchange reaction, and the molecular weight is controlled by the discharge of the phenol. As the reaction proceeds, the molecular weight of the polymer increases, the viscosity of the system increases, the boiling point of phenol is high, and the phenol cannot be easily removed from the high-viscosity melt. In the final polycondensation stage, the melt viscosity of the polycarbonate is much higher, small molecules generated by the reaction need to be continuously and rapidly removed to promote the positive balance direction of the polymerization reaction, the reaction temperature is increased, the vacuum degree of the system is improved, and the final polycondensation stage has higher requirements on stirring and heat transfer of reaction equipment.

In the polycarbonate process, a large amount of phenol is generated in the esterification and polycondensation stages, and needs to be condensed, recovered and continuously extracted on line. The vacuum degree of the system in the esterification stage is relatively low, the recovered phenol is generally continuously extracted by a conventional negative pressure pump, but the vacuum degree in the polycondensation stage is greatly improved, and the conventional negative pressure pump cannot work well. Phenol can be solidified at 42 ℃, the selected pump and the conveying pipeline need heat tracing, and the conventional negative pressure pump has difficulty in heat tracing. In industry, two storage tanks are alternately switched for use to convert vacuum extraction into normal pressure extraction, but the equipment investment is increased, the control is complex, and the tightness and the vacuum degree in a reactor can not be ensured during continuous extraction.

Meanwhile, the polycarbonate is easy to adhere to metal, has high viscosity, and is easy to cause local degradation in a pipeline due to long retention time of materials in the pipeline, so that a dead angle area appears, the pipeline is blocked for a long time, and the use efficiency of equipment is reduced.

Disclosure of Invention

In view of the defects of the prior art, the invention aims to provide a phenol continuous extraction system, a polycarbonate resin production system comprising the same and a production method. The continuous phenol extraction system provided by the invention can ensure the internal vacuum degree and the sealing property of the polycarbonate resin production system, simultaneously realize continuous extraction of the byproduct phenol, and simultaneously effectively recycle the extracted phenol.

In order to achieve the purpose, the invention adopts the following technical scheme:

In a first aspect, the invention provides a continuous phenol extraction system, wherein the continuous phenol extraction device comprises a gas-liquid separation device and a phenol collection device which are communicated, the gas-liquid separation device is used for adjusting the flow rate of a gas-liquid mixture entering the gas-liquid separation device, and at least one baffle is longitudinally arranged in the phenol collection device.

In the invention, the phenol continuous extraction system needs to be used together with the production system, and is mainly used for realizing the continuous extraction of the byproduct phenol in the production process, on one hand, the phenol can be recycled (or used for cleaning the production system, or used for raw materials of other chemical products after filtration, sedimentation and purification), and on the other hand, the phenol continuous extraction system is also beneficial to forward operation of main reaction.

The invention is designed primarily in that phenol can be solidified at 42 ℃, the selected pump and the delivery pipeline need heat tracing to prevent phenol from solidifying and blocking the pipeline, but the conventional negative pressure pump is difficult to realize heat tracing. Therefore, the invention is provided with the phenol continuous extraction system, realizes extraction and recovery and reuse of phenol at normal temperature, and specifically comprises the following steps: the invention is provided with a gas-liquid separation device, and when phenol in high-temperature byproducts (mainly comprising phenol and other impurities and byproducts carried by the phenol) discharged by a production system is not solidified, the gas-liquid separation is firstly carried out, so that the phenol is separated from micromolecular gases such as water vapor and alcohols. The phenol then enters the phenol collection device and is heated to prevent the phenol from solidifying. In addition, the phenol recovered by the phenol collecting device can be further settled to separate macromolecular impurities and particles in the phenol, and the phenol raw material obtained by recovery can be recycled; alternatively, the recovered phenol may optionally be used to clean various pieces of equipment of downstream production processes.

The invention particularly realizes the recovery and the reutilization of the extracted phenol on the basis of realizing the normal-temperature extraction of the phenol. It should be noted that the application scenario of the phenol continuous extraction system defined in the present invention is not limited to a specific production process or a certain type of production process, but is particularly applicable to a polycarbonate production process, mainly because: the polycarbonate has high viscosity, and is easy to generate local degradation in a pipeline when the polycarbonate stays in the pipeline for too long time, so that a dead angle area is generated, the pipeline is blocked for a long time, the production efficiency is seriously influenced, and the pipeline needs to be washed in time. However, this does not mean or suggest that the continuous phenol recovery system provided by the present invention is only suitable for the polycarbonate production process, and any other chemical production field requiring continuous phenol recovery can be suitable for the technical solution provided by the present invention.

As a preferable technical scheme, the gas-liquid separation device comprises a separation device shell, a feed inlet, an exhaust port and a liquid outlet are formed in the separation device shell, reaction products generated by an upstream production system enter the gas-liquid separation device through the feed inlet to be subjected to gas-liquid separation, gas is exhausted through the exhaust port, and liquid enters the phenol collection device through the liquid outlet.

Preferably, the liquid outlet is connected with a liquid discharging pipeline, the phenol collecting device is filled with cleaning liquid, and the outlet end of the liquid discharging pipeline extends below the liquid level of the cleaning liquid.

Preferably, the cleaning solution comprises phenol.

Preferably, the exhaust port is externally connected with a vacuum pumping device.

Preferably, a separation chamber is formed inside the separation device shell, and the separation chamber is used for reducing the flow velocity of the gas-liquid mixture entering the gas-liquid separation device.

preferably, the diameter of the cavity of the separation cavity is larger than the caliber of the feeding hole.

Preferably, the ratio of the cavity diameter of the separation cavity to the aperture of the feed inlet is (10-50): 1, and may be, for example, 10:1, 15:1, 20:1, 25:1, 30:1, 35:1, 40:1, 45:1 or 50:1, but is not limited to the recited values, and other values not recited in the range of values are also applicable.

In the invention, the phenol continuous extraction system is particularly suitable for a polycarbonate production system, a part of liquid is inevitably discharged along with the phenol in the phenol discharge process, when a gas-liquid mixture (comprising phenol, water vapor, alcohols and other small molecular substances) is discharged from the gas-liquid separation device, because the diameter of a cavity of the gas-liquid separation device is far larger than that of a discharge pipeline of the phenol, the flow rate is obviously reduced when the gas-liquid mixture is discharged into the gas-liquid separation device through the discharge pipeline, the retention time of the gas-liquid mixture in a separation cavity is greatly prolonged, the gas-liquid separation efficiency is improved, and the water vapor, the alcohols and other small molecular substances are discharged through an exhaust port under the negative pressure action of a vacuumizing device and optionally enter the alcohol recovery device for recovery treatment. Phenol in the gas-liquid mixture and liquid, oligomer, small particle impurities and the like carried by the phenol and the gas-liquid mixture flow into the phenol collecting device from the liquid discharging port through the liquid discharging pipeline under the action of gravity.

As a preferable technical scheme of the invention, the baffle plate is divided into an upper baffle plate and a lower baffle plate.

Preferably, the upper baffle is longitudinally fixed on the top surface of the phenol collecting device. In addition, a certain gap is required to be reserved between the upper baffle and the bottom surface of the gas-liquid separation device.

preferably, the lower baffle is longitudinally fixed on the bottom surface of the phenol collecting device. In addition, it is necessary to ensure that a gap is left between the lower baffle and the top surface of the gas-liquid separation device.

Preferably, the upper baffle and the lower baffle are arranged in a staggered manner. The upper baffle and the lower baffle are slightly different in fixed position, and other parameters such as size and material are the same.

a plurality of collecting and settling cavities which are relatively isolated are formed between two adjacent lower baffles, phenol (including entrained oligomer, liquid, residue, macromolecular substances, small particle impurities and the like) obtained by gas-liquid separation enters the first-stage collecting and settling cavity through a liquid discharge pipeline, and solid particles such as the residue, the macromolecular substances, the small particle impurities and the like are separated and settled to the bottom of the phenol collecting device under the action of gravity. Along with the continuous injection of phenol, phenol overflows to the second grade and collects the settling chamber, collects the second grade that subsides the separation of settling intracavity and carry out solid particulate matter at the second grade. After overflowing through the multistage collection and sedimentation cavity along with the phenol, the multistage sedimentation separation of solid particles in the phenol is realized. The arrangement of the upper baffle plate can ensure that phenol discharged into the phenol collecting device is firstly concentrated at the bottom of the collecting and settling cavity, and the sufficient cleaning liquid at the bottom of the liquid discharging pipeline is ensured. In addition, the phenol overflow device can also play a certain role in intercepting and buffering solid particles in the phenol overflow process, and prevents the solid particles from entering a next-stage collection and sedimentation cavity along with phenol overflow due to the excessively fast flow rate of phenol. The purpose of the design is that the phenol recovered by the phenol collecting device provided by the invention can be used for cleaning various reaction equipment of an upstream production system, and if a large amount of solid particles are contained in the phenol, pipelines are easily blocked in the circulating cleaning process, so that the phenol needs to be pretreated before the phenol is circulated and cleaned, and solid particles which are insoluble in the phenol are removed in advance.

as a preferred technical scheme of the invention, a shell of the phenol collecting device is provided with a liquid adding port, a vacuum pumping port, an overflow port and an emptying port.

preferably, a cleaning solution is injected into the phenol collecting device through the liquid adding port.

When the cleaning liquid in the phenol collection device is too little, the outlet end of the liquid discharge pipeline cannot be completely arranged below the liquid level of the cleaning liquid, the cleaning liquid (optionally phenol) can be manually added through the liquid adding port, and the liquid sealing effect is achieved.

Preferably, the vacuumizing port is externally connected with a vacuumizing device.

when byproducts (including phenol, alcohol substances and water vapor) extracted by an upstream production system enter the gas-liquid separation device, the gas-liquid separation device is pumped out through the exhaust port to form a negative pressure state in the gas-liquid separation device, and the vacuum degree formed in the phenol collection device is kept consistent with the vacuum degree in the gas-liquid separation device by pumping out the phenol collection device through the vacuum-pumping port of the phenol collection device.

Preferably, the overflow port is externally connected with an overflow pipeline.

preferably, the evacuation port is externally connected with an evacuation pipeline.

when the phenol collecting device needs to be cleaned or overhauled, all liquid in the phenol collecting device can be emptied through the emptying pipeline.

Preferably, an evacuation valve is arranged on the evacuation pipeline.

Preferably, the outlet end of the overflow pipeline is connected to an emptying pipeline, and the liquid level in the phenol collecting device is discharged from the emptying pipeline through the overflow pipeline when reaching the height of the overflow port.

Preferably, the bottom of the phenol collecting device is provided with a heating device.

Preferably, the bottom of the phenol collecting device is further provided with a cleaning opening, the cleaning opening is located between the adjacent lower baffle and the upper baffle, and the cleaning opening is externally connected with a cleaning medium pipeline.

When the sediment substances accumulated at the bottom of the phenol collecting device cause blockage, steam can be blown in through the cleaning openings to clean the phenol collecting device in a segmented manner when the phenol collecting device needs to be cleaned, and the service cycle of the phenol collecting device is prolonged.

The invention provides a working process of a phenol collecting device, which comprises the following steps:

(1) Before the phenol continuous extraction process begins, injecting sufficient cleaning liquid (phenol) into a phenol collection device in advance, wherein in the phenol continuous extraction process, the outlet end of a liquid discharge pipeline is always positioned below the liquid level of the cleaning liquid so as to ensure the vacuum degree and the sealing property in the system and realize the liquid sealing effect;

(2) the phenol obtained by the separation of the gas-liquid separation device and the liquid and the low polymer carried by the phenol enter the phenol collection device through the liquid discharge pipeline under the action of gravity, and are subjected to multistage collection and sedimentation cavities under the action of the upper baffle and the lower baffle to realize multistage sedimentation separation, and when too much cleaning liquid exists in the phenol collection device, the cleaning liquid flows out of the overflow port.

(3) And after the phenol is continuously extracted, steam is blown in through the cleaning port to clean the collecting and settling cavity in sections.

in a second aspect, the present invention provides a polycarbonate resin production system, which comprises a reaction unit, a phenol extraction unit and a granulation unit, wherein the phenol extraction unit and the granulation unit are respectively connected with the reaction unit.

the phenol extraction unit comprises the phenol continuous extraction system of the first aspect.

The invention organically integrates the phenol continuous extraction system provided by the first aspect with the existing polycarbonate resin production system. In the polycarbonate process, a large amount of phenol is generated in the esterification and polycondensation stages, and needs to be condensed and recycled and continuously extracted on line so as to promote the forward reaction. The invention adds a specially designed phenol continuous extraction system on the basis of the existing polycarbonate resin production system to realize the continuous extraction of phenol, and cleans the original polycarbonate resin production system by using the phenol collected by the phenol continuous extraction system to dissolve and depolymerize the polycarbonate melt remained in the pipeline into oligomer, and the oligomer is dissolved in the phenol and flows back to the collection chamber for recycling.

as a preferable technical scheme of the invention, the reaction unit comprises a transesterification reaction device and a final polycondensation reaction device which are connected in sequence according to a polycarbonate production process route.

Preferably, the granulation unit comprises a mixing device, a filtering device and an extrusion granulation device which are connected in sequence.

Preferably, the extrusion granulation device is a twin-screw extruder.

preferably, the final polycondensation reaction device is connected with a gas-liquid separation device through a phenol extraction pipeline.

Preferably, the outlet end of the phenol extraction pipeline extends into the gas-liquid separation device through a feed inlet formed in the top of the gas-liquid separation device.

Preferably, the final polycondensation reaction device is connected with the mixing device through a discharge pipeline.

preferably, a discharge valve is arranged on the discharge pipeline.

according to a preferable technical scheme of the invention, the bottom of the phenol collecting device is connected with a flushing pipeline, the outlet end of the flushing pipeline is connected with a discharging pipeline, and phenol collected by the phenol collecting device is discharged into the discharging pipeline through the flushing pipeline to be used as cleaning liquid for cleaning the final polycondensation reaction device and the mixing device.

preferably, a pressurizing device is arranged on the flushing pipeline.

Preferably, the filtering device is connected with the phenol collecting device through a waste liquid return pipeline, and waste liquid filtered by the filtering device is recycled to the phenol collecting device through the waste liquid return pipeline for replenishing consumed cleaning liquid.

Preferably, a pressure boosting device is arranged on the waste liquid return pipeline.

In a third aspect, the present invention provides a method for producing a polycarbonate resin, which is carried out in the polycarbonate resin production system according to the second aspect.

The production method comprises the following steps:

The production raw materials are subjected to esterification reaction and polycondensation reaction in a reaction unit to obtain a polycarbonate melt and a byproduct;

(II) continuously extracting the by-product discharged in the step (I) through a phenol extraction unit;

(III) extruding and granulating the polycarbonate melt obtained in the step (I) in a granulating unit to obtain the polycarbonate resin.

As a preferred technical scheme of the invention, the production raw materials in the step (I) comprise reaction raw materials and a catalyst.

preferably, the reaction starting materials include diphenyl carbonate and dihydroxy compounds.

Preferably, the catalyst comprises one or a combination of at least two of basic ionic liquid, alkali metal or alkaline earth metal compounds.

Preferably, the esterification reaction is carried out in a transesterification reaction apparatus.

Preferably, the esterification reaction is carried out under a nitrogen atmosphere.

Preferably, the esterification reaction temperature is 80 ~ 180 ℃, for example can be 80 degrees, 90 degrees, 100 degrees, 110 degrees, 120 degrees, 130 degrees, 140 degrees, 150 degrees, 160 degrees, 170 degrees or 180 ℃, but not limited to the value, the numerical range of other not listed values are also applicable.

preferably, the reaction time of the esterification reaction is 0.1 to 6 hours, for example, 0.1 hour, 0.5 hour, 1 hour, 1.5 hour, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours or 6 hours, but is not limited to the recited values, and other values not recited in the numerical range are also applicable.

preferably, the polycondensation reaction is carried out in a final polycondensation reaction apparatus.

preferably, the polycondensation reaction temperature is 180 ~ 300 ℃, for example can be 180 ℃, 190 ℃, 200 ℃, 210 ℃, 220 ℃, 230 ℃, 240 ℃, 250 ℃, 260 ℃, 270 ℃, 280 ℃, 290 ℃ or 300 ℃, but not limited to the value, the numerical value range of other not listed in the same application.

Preferably, the reaction time of the polycondensation reaction is 0.1 to 6 hours, for example, 0.1 hour, 0.5 hour, 1 hour, 1.5 hour, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours or 6 hours, but is not limited to the recited values, and other values not recited in the range of the values are also applicable.

Preferably, the polycondensation reaction is carried out under a nitrogen atmosphere. The by-products are removed during the polycondensation reaction by reducing the pressure stepwise.

It should be emphasized that the main inventive point of the present invention is to organically integrate the phenol continuous extraction system with the existing polycarbonate resin production system, the production process route of the polycarbonate resin including the process parameters involved in the process is not specifically required and limited, and the reaction unit and the granulation unit provided by the present invention and the corresponding reaction process parameters and extrusion granulation process parameters thereof can be directly replaced by the polycarbonate resin production system and production process parameters disclosed in the prior art or not disclosed in the new technology.

as a preferred technical scheme of the invention, the by-products in the step (II) comprise phenol, alcohols and water vapor.

Preferably, the continuous production process of step (ii) comprises:

The flow rate of the by-product is reduced after the by-product enters the gas-liquid separation device, the air is exhausted outwards from the exhaust port of the gas-liquid separation device, so that the interior of the gas-liquid separation device is kept in a negative pressure state, meanwhile, the vacuum degree in the phenol collection device is kept consistent with the vacuum degree in the gas-liquid separation device by exhausting outwards from the vacuumizing port of the phenol collection device, water vapor and alcohols in the by-product are exhausted from the exhaust port under the action of negative pressure, and the phenol enters the phenol collection device through a liquid discharge pipeline to be recovered.

Preferably, step (ii) further comprises:

(1) using phenol recovered by a phenol collecting device as a cleaning solution to clean the final polycondensation reaction device and the mixing device;

(2) And (4) stopping extracting the by-product after the reaction is finished, introducing a cleaning medium into the phenol collecting device through the cleaning port, and cleaning the bottom of the phenol collecting device.

Preferably, the cleaning medium is steam.

Preferably, the extrusion granulation process of step (iii) comprises:

and (3) mixing the polycarbonate melt with the auxiliary agent in a mixing device, introducing the mixture into a filtering device, and extruding and granulating the filtered polycarbonate melt by an extruding and granulating device.

Preferably, the waste liquid filtered by the filtering device is returned to the phenol collecting device to be used as a cleaning liquid to replenish the cleaning liquid consumed in the cleaning process.

The recitation of numerical ranges herein includes not only the above-recited numerical values, but also any numerical values between non-recited numerical ranges, and is not intended to be exhaustive or to limit the invention to the precise numerical values encompassed within the range for brevity and clarity.

The system refers to an equipment system, or a production equipment.

Compared with the prior art, the invention has the beneficial effects that:

(1) The improved phenol continuous extraction system needs to be used together with a production system, is mainly used for realizing the normal-temperature continuous extraction of the byproduct phenol in the production process, realizes the sedimentation separation of the byproduct by arranging the baffling baffle, and the phenol obtained by separation can be used for flushing the production system.

(2) the invention adds the phenol continuous extraction system on the basis of the original polycarbonate resin production system to realize the continuous extraction of phenol, and cleans the original polycarbonate resin production system by using the phenol collected by the phenol continuous extraction system, so as to dissolve and depolymerize the polycarbonate melt remained in the pipeline into oligomer, dissolve the oligomer in the phenol and return the oligomer to the collection chamber for recycling. The online real-time cleaning is realized, the production period is shortened, and the production efficiency is improved.

drawings

FIG. 1 is a schematic structural view of a gas-liquid separation apparatus according to an embodiment of the present invention;

FIG. 2 is a schematic structural view of a phenol collection apparatus according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a phenol continuous-extraction system according to an embodiment of the present invention;

FIG. 4 is a schematic structural view of a polycarbonate resin production system provided in example 4 of the present invention;

FIG. 5 is a schematic view of the structure of a polycarbonate resin production system provided in example 5 of the present invention;

FIG. 6 is a schematic view showing the structure of a polycarbonate resin production system according to example 6 of the present invention.

wherein, 100-reaction unit; 110-ester exchange reaction device; 120-final polycondensation reaction device; 130-a discharge valve; 200-a granulation unit; 210-a mixing device; 220-a filtration device; 230-twin screw extruder; a 300-phenol continuous production system; 310-a gas-liquid separation device; 311-phenol production line; 312-feed inlet; 313-an exhaust port; 314-drain port; 315-drain line; 316-a separation chamber; a 320-phenol collection device; 321-a lower baffle; 322-an upper baffle; 323-filling opening; 324-an overflow line; 325-evacuation line; 326-evacuation valve; 327-a purge port; 400, 500-booster pump.

Detailed Description

The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings.

In a specific embodiment, the present embodiment provides a continuous phenol production system 300, and the continuous phenol production system 300 includes a gas-liquid separation device 310 and a phenol collection device 320 which are communicated with each other as shown in fig. 1.

The gas-liquid separation device 310 has a specific structure as shown in fig. 2, and includes a separation device housing, the housing is provided with a feed inlet 312, an exhaust outlet 313 and a liquid outlet 314, a reaction product generated in an upstream production system enters the gas-liquid separation device through the feed inlet 312 for gas-liquid separation, gas is discharged through the exhaust outlet 313, and liquid enters the phenol collection device 320 through the liquid outlet 314. The liquid outlet 314 is connected with a liquid outlet pipeline 315, the phenol collecting device 320 is filled with cleaning liquid, the outlet end of the liquid outlet pipeline 315 extends below the liquid level of the cleaning liquid (as shown in fig. 1), and the gas outlet 313 is externally connected with a vacuum pumping device.

The separation chamber 316 is formed inside the separator housing, and the separation chamber 316 is used to reduce the flow rate of the gas-liquid mixture entering the gas-liquid separator 310. The diameter of the cavity of the separation cavity 316 is larger than the caliber of the feed port 312, when the gas-liquid mixture enters the separation cavity 316 through the feed port 312, the flow velocity is reduced due to the increase of the flow cross-sectional area, the residence time of the gas-liquid mixture in the separation cavity 316 is prolonged, the gas in the gas-liquid mixture is exhausted through the exhaust port 313 under the action of the vacuum extractor, and the ratio of the diameter of the cavity of the separation cavity 316 to the caliber of the feed port 312 can be selected from (10-50): 1.

The concrete structure of the phenol collecting device 320 is shown in fig. 3, and a filling port 323, a vacuum pumping port, an overflow port and an evacuation port are arranged on the shell of the phenol collecting device 320. The cleaning liquid is injected into the phenol collecting device 320 in advance through the liquid filling port 323, so that the outlet end of the liquid discharging pipeline 315 is always positioned below the liquid level of the cleaning liquid in the continuous extraction process. The vacuumizing port is externally connected with a vacuumizing device, and the phenol collecting device 320 is emptied through the vacuumizing port, so that the vacuum degree in the phenol collecting device 320 is consistent with the vacuum degree in the gas-liquid separating device 310, and the gas-liquid separating effect is realized. The overflow port is externally connected with an overflow pipeline 324, the emptying port is externally connected with an emptying pipeline 325, an emptying valve 326 is arranged on the emptying pipeline 325, the outlet end of the overflow pipeline 324 is connected with the emptying pipeline 325, and the liquid level in the phenol collecting device 320 is discharged from the emptying pipeline 325 through the overflow pipeline 324 when reaching the height of the overflow port.

At least one baffle is longitudinally arranged in the phenol collection device 320, the baffle is divided into an upper baffle 322 and a lower baffle 321, the upper baffle 322 is longitudinally fixed on the top surface of the phenol collection device 320 and keeps a certain gap with the bottom surface, the lower baffle 321 is longitudinally fixed on the bottom surface of the phenol collection device 320 and keeps a certain gap with the top surface, the upper baffle 322 and the lower baffle 321 are arranged in a staggered mode to form a plurality of relatively isolated collection settling cavities, phenol obtained by gas-liquid separation enters the first-stage collection settling cavity through a liquid discharge pipeline 315, large-particle residues and macromolecular substances in the phenol are separated and settled to the bottom of the phenol collection device 320 under the action of gravity, along with continuous injection of phenol, the phenol overflows to the second-stage collection settling cavity, secondary settling separation of residues and other particles is realized, and after the multi-stage collection settling cavities, the phenol also realizes multi-stage settling separation.

the bottom of the phenol collection device 320 is provided with a heating device (not shown in the figure), the bottom of the phenol collection device 320 is further provided with a cleaning opening 327, the cleaning opening 327 is located between the adjacent lower baffle 321 and the upper baffle 322, and the cleaning opening 327 is externally connected with a cleaning medium pipeline.

In another embodiment, the present invention provides a polycarbonate resin production system, as shown in fig. 4, 5 and 6, comprising a reaction unit 100, a phenol extraction unit and a granulation unit 200, wherein the phenol extraction unit and the granulation unit 200 are respectively connected to the reaction unit 100, and the phenol extraction unit is a phenol continuous extraction system 300 of one embodiment.

the reaction unit 100 includes a transesterification reaction apparatus 110 and a final polycondensation reaction apparatus 120 connected in series according to a polycarbonate production process route. The granulation unit 200 includes a mixing device 210, a filtering device 220, and a twin-screw extruder 230, which are connected in sequence. The final polycondensation reaction device 120 is connected with the gas-liquid separation device 310 through a phenol extraction pipeline 311, and the outlet end of the phenol extraction pipeline 311 extends into the gas-liquid separation device through a feed inlet 312 formed in the top of the gas-liquid separation device 310. The final polycondensation reaction apparatus 120 is connected to the mixing apparatus 210 through a discharge line, and a discharge valve 130 is provided on the discharge line.

Optionally, as shown in fig. 5 and fig. 6, a flushing pipeline is connected to the bottom of the phenol collecting device 320, an outlet end of the flushing pipeline is connected to the discharging pipeline, phenol collected by the phenol collecting device 320 is discharged into the discharging pipeline through the flushing pipeline as a cleaning solution to clean the final polycondensation reaction device 120 and the mixing device 210, and a booster pump 400 is disposed on the flushing pipeline.

Optionally, as shown in fig. 5, the filtering device 220 is connected to the phenol collecting device 320 through a waste liquid return line, the waste liquid filtered by the filtering device 220 is recycled to the phenol collecting device 320 through the waste liquid return line for replenishing the consumed cleaning liquid, and the waste liquid return line is provided with a booster pump 500.

In another embodiment, the present invention provides a method for producing a polycarbonate resin, which is carried out in the above polycarbonate resin production system.

The production method specifically comprises the following steps:

the production raw materials are subjected to esterification reaction and polycondensation reaction in the reaction unit 100 to obtain a polycarbonate melt and byproducts, the esterification reaction and the polycondensation reaction are carried out in a nitrogen atmosphere, and the byproducts are removed by reducing the pressure step by step in the polycondensation reaction process.

(II) after the byproducts (mainly comprising phenol, alcohol and water vapor) discharged in the step (I) enter the gas-liquid separation device 310, the flow rate is reduced, the gas is exhausted outwards through an exhaust port 313 of the gas-liquid separation device to keep the interior of the gas-liquid separation device in a negative pressure state, meanwhile, the vacuum degree in the phenol collection device 320 is kept consistent with the vacuum degree in the gas-liquid separation device by exhausting outwards through a vacuumizing port of the phenol collection device 320, the water vapor and the alcohol in the byproducts are exhausted through the exhaust port 313 under the action of the negative pressure, the phenol enters the phenol collection device 320 through a liquid discharge pipeline 315 to be recovered, and impurity particles carried in the phenol are precipitated and separated for multiple times in the phenol collection device 320 and then are precipitated to the bottom of the phenol collection device 320;

After the reaction is finished, the byproduct is stopped to be extracted, and a cleaning medium is introduced into the phenol collecting device 320 through the cleaning opening 327 to clean and flush the bottom of the phenol collecting device 320. Meanwhile, the final polycondensation reaction apparatus 120 and the mixing apparatus 210 are cleaned using the phenol recovered by the phenol collecting apparatus 320 (the polycarbonate resin production system shown in fig. 5 and 6 can perform a cleaning function).

(III) mixing the polycarbonate melt obtained in the step (I) with an auxiliary agent in a mixing device 210, introducing the mixture into a filtering device 220, and extruding and granulating the filtered polycarbonate melt by a double-screw extruder 230. Alternatively, the filtered waste liquid is returned to the phenol collecting device 320 to be used as a cleaning liquid for replenishing and cleaning the phenol consumed (the polycarbonate resin production system shown in fig. 5 can perform this function).