Device and method for continuous alkali washing and water washing of benzoate

Abstract

The invention provides a device and a method for continuous alkali washing and water washing of benzoate. The device comprises an alkali washing device and a water washing device, wherein the alkali washing device comprises an alkali washing kettle, an alkali washing crude product discharging pipeline communicated with the top of the alkali washing kettle, an alkali washing wastewater discharging pipeline communicated with the bottom of the alkali washing kettle, and an alkali washing feeding pipeline communicated with the side wall of the alkali washing kettle; the washing device comprises a washing kettle, a washing wastewater discharging pipeline communicated with the top of the washing kettle, a washing crude product discharging pipeline communicated with the bottom of the washing kettle, and a washing feeding pipeline communicated with the side wall of the washing kettle and the alkali washing crude product discharging pipeline; multi-stage oil-water layering devices are arranged in inner cavities of the alkali washing kettle and the water washing kettle and comprise stirring assemblies arranged in the middles of the inner cavities and multi-stage partition plate assemblies arranged on the upper portions and the lower portions of the inner cavities respectively. The device can realize automatic layering of feed liquid with different densities while ensuring that raw materials are fully mixed and reacted, so that the processes of feeding, alkali washing, water washing, discharging and the like of benzoate can be continuously carried out.

Description

Technical Field

[0001] The present application relates to the technical field of benzoic acid ester synthesis, and in particular to a device and method for continuous alkaline washing and water washing of benzoic acid ester. Background Art

[0002] Benzoic acid ester is an important industrial solvent and synthetic fragrance, and its use is very extensive. In the industrial synthesis of benzoic acid ester, usually a strong acid catalyst such as sulfuric acid and sulfonic acid is used to catalyze the esterification reaction between benzoic acid and the corresponding alcohol to synthesize benzoic acid ester products. Under this condition, it is difficult for benzoic acid to react completely, and often 0.5-3% of benzoic acid remains and cannot be completely esterified. In order to ensure the quality of benzoic acid ester, it is usually necessary to remove the unreacted benzoic acid by alkali washing, and then remove the alkali solution and salt by multiple water washings. The crude product obtained can be distilled to obtain the finished benzoic acid ester.

[0003] In the existing synthesis process, the alkali washing process is usually to add inorganic bases such as sodium hydroxide or sodium carbonate to the reactor, and an acid-base neutralization reaction occurs under stirring conditions to remove the unesterified benzoic acid. Since the density of the wastewater containing alkali and salt obtained after alkali washing is greater than that of the crude product benzoate, it is necessary to stop stirring and stand for a period of time after the alkali washing is completed, and the alkali washing wastewater is discharged through the discharge port of the lower layer of the reactor after stratification. Then add clean water to the kettle, start stirring and wash the crude product, and then stop stirring and wait for stratification. However, since the density of benzoate is greater than that of water, the washing wastewater is located in the upper layer and cannot be directly discharged from the lower layer discharge port. In order to wash the benzoate after alkali washing multiple times, it is often necessary to use two washing kettles to pour materials back and forth: first wash in the first washing kettle, and after standing and stratifying, the lower layer of the crude benzoate is first pumped to the second washing kettle, and then the washing wastewater in the first washing kettle is discharged through the lower discharge port. Then a second washing is performed in the second washing kettle. If only two water washings are required, after washing in the second water washing kettle and standing for stratification, the obtained crude benzoate can be pumped to a distillation tower for purification; if more than two water washings are required, the crude benzoate needs to be pumped to the first water washing kettle, and the material needs to be poured back and forth to complete multiple water washings. The overall process is very cumbersome, requiring a lot of equipment, time and labor, and cannot be automated. In addition, the above-mentioned intermittent batch alkali washing and water washing methods require a lot of time to wait for stratification, and the separation interface formed after stratification is often difficult to grasp. Close manual observation or the use of multiple automatic control equipment such as interface instruments and cut-off valves can achieve automated oil-water stratification, material transfer and cut-off. The manpower and equipment costs are high, the operation is complicated, and it is time-consuming and labor-intensive. Summary of the invention

[0004] In view of the technical problems existing in the background technology, the present application provides a device and method for continuous alkali washing and water washing of benzoic acid esters. The device can realize automatic stratification of slurries with different densities while ensuring sufficient mixing and reaction of the raw materials, so that the feeding, alkali washing, water washing and discharging processes of benzoic acid esters synthesized by the esterification method can be carried out continuously.

[0005] In a first aspect, an embodiment of the present application provides a device for continuous alkali washing and water washing of benzoic acid esters, including an alkali washing device and a water washing device;

[0006] The alkali washing device comprises an alkali washing kettle, an alkali washing crude product discharge pipe connected to the top of the alkali washing kettle, an alkali washing wastewater discharge pipe connected to the bottom of the alkali washing kettle, an alkali washing feed pipe connected to the side wall of the alkali washing kettle and corresponding flow control components;

[0007] The water washing device comprises a water washing kettle, a water washing wastewater discharge pipe connected to the top of the water washing kettle, a water washing crude product discharge pipe connected to the bottom of the water washing kettle, a water washing feed pipe connected to the side wall of the water washing kettle and the alkali washing crude product discharge pipe, and corresponding flow control components;

[0008] The inner cavities of the alkaline washing kettle and the water washing kettle are both provided with a multi-stage oil-water stratification device; the multi-stage oil-water stratification device comprises a stirring assembly arranged in the middle of the inner cavity and an upper multi-stage baffle assembly and a lower multi-stage baffle assembly respectively arranged in the upper and lower parts of the inner cavity.

[0009] In the technical solution of the embodiment of the present application, a multi-stage oil-water stratification device is arranged in the inner cavity of the alkali washing kettle and the water washing kettle, and the stirring component can be used to promote the full progress of the acid-base neutralization reaction. At the same time, the upper multi-stage baffle component and the lower multi-stage baffle component are used to realize automatic oil-water stratification. During the stratification process, the stirring component can continue to operate, thereby realizing automatic oil-water stratification during the continuous reaction process.

[0010] In some embodiments, the upper multi-stage baffle assembly and the lower multi-stage baffle assembly each include a plurality of baffles alternately arranged on both sides of the inner cavity from top to bottom; the baffles are inclined at a certain angle relative to the horizontal plane.

[0011] In this embodiment, a plurality of partitions arranged alternately from top to bottom are provided at the upper and lower parts of the inner cavities of the alkali washing kettle and the water washing kettle, and the partitions are inclined relative to the horizontal plane, so that the feed liquid entering the inner cavity through the feed pipe can be fully mixed and reacted under the action of the stirring component, and can be demulsified under the action of the partition, and relatively still and stratified in a relatively stable environment formed by the multi-stage partition assembly, thereby effectively separating the two phases with different densities, ensuring that the pure phase with relatively small density is located at the top of the inner cavity, and the pure phase with large density is located at the bottom of the inner cavity, and then the two phases are discharged separately through the discharge pipes located at the top and bottom respectively, thereby realizing continuous feeding, automatic stratification and continuous discharge.

[0012] In some embodiments, the angle between the partition and the horizontal plane is 10-20°, and the area of ​​the partition accounts for 85%-95% of the cross-sectional area of ​​the inner cavity.

[0013] In this embodiment, by controlling the angle between the partition and the horizontal plane and the area of ​​the partition, it is possible to ensure effective stratification of two phases with different densities in a smaller occupied space, thereby improving the automatic stratification effect.

[0014] In some embodiments, the upper multi-stage partition assembly includes a first partition, a second partition, and a third partition alternately arranged on both sides of the inner cavity from top to bottom; the first partition is tilted downward from the side where the discharge pipe at the top of the inner cavity is located, the second partition is tilted upward from the opposite side of the discharge pipe at the top of the inner cavity, and the third partition is tilted upward from the side where the discharge pipe at the top of the inner cavity is located.

[0015] In this embodiment, by setting three layers of partitions and limiting the position and inclination direction of each partition, the stirred mixture can be demulsified when it hits the third partition, and the low-density liquid phase continuously floats up along the inclination direction of the third partition and enters between the third partition and the second partition, where it is less affected by the stirring component, and the mixture is further stratified. A small amount of high-density liquid phase mixed in the mixture sinks along the first partition, and the low-density liquid phase further floats up along the inclination direction of the second partition and enters between the second partition and the first partition, where the interference of the stirring component is further reduced, which can further promote the stratification of the mixed phase, so that the liquid phase entering above the first partition is all low-density liquid phase, thereby discharging the low-density pure phase after automatic separation through the discharge pipe at the top of the inner cavity.

[0016] In some embodiments, the lower multi-stage partition assembly includes a fourth partition, a fifth partition and a sixth partition alternately arranged on both sides of the inner cavity from top to bottom; the sixth partition is inclined upward from the side where the discharge pipe at the bottom of the inner cavity is located, the fifth partition is inclined downward from the opposite side of the discharge pipe at the bottom of the inner cavity, and the fourth partition is inclined downward from the side where the discharge pipe at the bottom of the inner cavity is located.

[0017] In this embodiment, by setting three layers of partitions and limiting the position and inclination direction of each partition, the stirred mixture can be demulsified when it hits the fourth partition, and the high-density liquid phase continues to sink along the inclination direction of the fourth partition and enters between the fourth partition and the fifth partition, where it is less affected by the stirring component, and the mixture is further stratified. A small amount of low-density liquid phase mixed in the mixture floats along the fourth partition, and the high-density liquid phase further sinks along the inclination direction of the fifth partition and enters between the fifth partition and the sixth partition, where the interference of the stirring component is further reduced, which can further promote the stratification of the mixed phase, so that the liquid phase entering under the sixth partition is all high-density liquid phase, thereby discharging the automatically separated high-density pure phase through the discharge pipe at the bottom of the inner cavity.

[0018] In some embodiments, the flow control component is provided in the alkali washing crude product discharge pipe, the alkali washing wastewater discharge pipe, the alkali washing feed pipe, the water washing wastewater discharge pipe, the water washing crude product discharge pipe, and the water washing feed pipe; the flow control component includes a control valve and a mass flow meter.

[0019] In this embodiment, by arranging control valves and mass flow meters in each pipeline, the mass flow of the corresponding pipeline can be accurately controlled by adjusting the opening and closing degree of the control valve to ensure that the quality of the input liquid is basically consistent with the corresponding discharged liquid, thereby ensuring that the ratio of the two phases in the kettle remains basically constant.

[0020] In some embodiments, online densitometers are respectively disposed at the upper and lower portions of the inner cavity.

[0021] In this embodiment, by arranging online density meters between the first partition plate and the second partition plate, and between the fifth partition plate and the sixth partition plate, respectively, the density of the solution in the upper and lower parts of the inner cavity can be monitored in real time, so as to verify the automatic stratification effect of the device and whether the flow distribution of the upper and lower discharge ports is appropriate. According to the corresponding density monitoring results, the opening of the upper and lower discharge port flow control valves is adjusted in time, so that the material in the kettle always maintains an oil-water ratio close to 1:1, thereby ensuring the alkali washing and water washing efficiency and the oil-water stratification effect of the device.

[0022] In some embodiments, the alkali washing feed pipeline includes an alkali solution feed pipeline and a reaction crude product feed pipeline; the connecting port between the alkali solution feed pipeline and the alkali washing kettle is located above the connecting port between the reaction crude product feed pipeline and the alkali washing kettle.

[0023] In this embodiment, by respectively inputting the alkali solution and the crude reaction product into the alkali washing kettle through two feed pipes, it is convenient to separately regulate the flow rate of each feed pipe; on this basis, by setting the feed pipe corresponding to the alkali solution with relatively larger density at a relatively higher position, and setting the feed pipe corresponding to the crude reaction product with relatively smaller density at a relatively lower position, it is more conducive to promoting the full mixing of the two and quickly completing the acid-base neutralization reaction.

[0024] In some embodiments, the water washing feed pipeline includes a clean water feed pipeline and an alkali washing crude product feed pipeline, and the alkali washing crude product feed pipeline is connected to the alkali washing crude product discharge pipeline; the connecting port between the clean water feed pipeline and the water washing kettle is located below the connecting port between the alkali washing crude product feed pipeline and the water washing kettle.

[0025] In this embodiment, by respectively feeding clean water and alkali-washed crude product into the water washing kettle through two feed pipes, it is convenient to separately regulate the flow of each feed pipe; on this basis, by setting the feed pipe corresponding to the alkali-washed crude product with relatively larger density at a relatively higher position, and setting the feed pipe corresponding to the clean water with relatively smaller density at a relatively lower position, it is more conducive to promoting sufficient mixing of the two and water washing and desalination.

[0026] In a second aspect, the present application provides a method for continuous alkaline washing and water washing of benzoic acid esters, using the device provided in the above embodiment, comprising the following steps:

[0027] The alkali washing liquid and the crude product of the benzoic acid ester reaction synthesized by the esterification method are fed into the alkali washing kettle through the alkali washing feed pipe, and the stirring component in the alkali washing kettle is turned on to perform alkali washing under stirring. The alkali washing wastewater and the alkali washing crude product generated during the alkali washing process are automatically separated under the action of the multi-stage partition plate and discharged through the alkali washing wastewater discharge pipe and the alkali washing crude product discharge pipe respectively; during the alkali washing process, the alkali washing kettle is always filled with liquid phase;

[0028] Clean water and the alkali-washed crude product are fed into the washing kettle through the washing feed pipe, and the stirring component in the washing kettle is turned on to perform water washing under stirring. The washing wastewater and the washing crude product generated during the washing process are automatically stratified under the action of the multi-stage partitions and are discharged through the washing wastewater discharge pipe and the washing crude product discharge pipe respectively; during the washing process, the washing kettle is always filled with liquid phase.

[0029] In the technical scheme of the embodiment of the present application, by adopting a device for continuous alkali washing and water washing of benzoic acid esters, the alkali washing liquid and the crude benzoic acid ester product can be continuously fed into the alkali washing kettle while keeping the stirring component in continuous operation, so that they are fully reacted and automatically stratified in the alkali washing kettle, and the alkali washing wastewater and the alkali washing crude product are continuously discharged through the alkali washing wastewater discharge pipe at the bottom and the alkali washing crude product discharge pipe at the top respectively; the discharged alkali washing crude product enters the water washing kettle again, and is automatically stratified after being fully mixed with the continuously introduced clean water, so that the washing wastewater and the washing crude product are continuously discharged through the washing wastewater discharge pipe at the top and the washing crude product discharge pipe at the bottom respectively, and the entire feeding, alkali washing, water washing, and discharging process can be carried out continuously, and is easy to operate and easy to control, which can meet the needs of practical applications.

[0030] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings used in the present application. Obviously, the drawings described below are only some embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 This is a schematic diagram of the structure of a device for continuous alkaline washing and water washing of benzoic acid esters provided in an embodiment of the present application.

[0033] Explanation of the reference numerals: 10, alkali washing kettle; 11, alkali washing crude product discharge pipe; 12, alkali washing wastewater discharge pipe; 13, alkali solution feed pipe; 14, reaction crude product feed pipe; 20, water washing kettle; 21, water washing wastewater discharge pipe; 22, water washing crude product discharge pipe; 23, clean water feed pipe; 24, alkali washing crude product feed pipe; 30, stirring assembly; 41, first partition; 42, second partition; 43, third partition; 44, fourth partition; 45, fifth partition; 46, sixth partition; 50, control valve; 60, mass flow meter; 71, first online density meter; 72, second online density meter. DETAILED DESCRIPTION

[0034] The following embodiments of the technical solution of the present application are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0036] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0037] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0038] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). In the description of the embodiments of the present application, the orientation or positional relationship indicated by the technical terms "top", "bottom", "upper", "lower", "inner", "horizontal", "cross" and the like is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0039] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0040] Since the existing benzoate alkali washing and water washing device cannot operate continuously, the alkali washing needs to be left standing and waiting for stratification after the reaction, and the water washing needs two water washing kettles 20 to pour materials back and forth, and each time the materials are poured, it is also necessary to stand and wait for stratification. The overall process is time-consuming, and the separation interface formed after standing and stratifying is often difficult to grasp, which affects the production efficiency of benzoate. Based on this, the present application provides a device and method for continuous alkali washing and water washing of benzoate, by arranging a multi-stage oil-water stratification device in the inner cavity of the alkali washing kettle 10 and the water washing kettle 20, while ensuring that the raw materials are fully mixed and reacted, the feed liquid of different densities is automatically stratified, so that the feeding, alkali washing, water washing and discharging processes of the benzoate synthesized by the esterification method can be carried out continuously.

[0041] See also Figure 1 The device for continuous alkali washing and water washing of benzoic acid esters provided in the embodiment of the present application includes an alkali washing device and a water washing device. Among them, the alkali washing device includes an alkali washing kettle 10, an alkali washing crude product discharge pipe 11 connected to the top of the alkali washing kettle 10, an alkali washing wastewater discharge pipe 12 connected to the bottom of the alkali washing kettle 10, an alkali washing feed pipe connected to the side wall of the alkali washing kettle 10 and a corresponding flow control component; the water washing device includes a water washing kettle 20, a water washing wastewater discharge pipe 21 connected to the top of the water washing kettle 20, a water washing crude product discharge pipe 22 connected to the bottom of the water washing kettle 20, a water washing feed pipe connected to the side wall of the water washing kettle 20 and the alkali washing crude product discharge pipe 11, and a corresponding flow control component. The inner chambers of the alkaline washing kettle 10 and the water washing kettle 20 are both provided with a multi-stage oil-water stratification device; the multi-stage oil-water stratification device includes a stirring assembly 30 arranged in the middle of the inner chamber, an upper multi-stage baffle assembly arranged in the upper part of the inner chamber, and a lower multi-stage baffle assembly arranged in the lower part of the inner chamber.

[0042] By arranging a multi-stage oil-water stratification device in the inner cavity of the alkali washing kettle 10 and the water washing kettle 20, the stirring assembly 30 can be used to promote the full progress of the reaction, and the upper multi-stage baffle assembly and the lower multi-stage baffle assembly can be used to achieve automatic stratification. During the stratification process, the stirring assembly 30 can continue to operate, thereby achieving automatic stratification during the continuous reaction process. After automatic stratification, the top of the inner cavity is a low-density pure phase, which can be discharged through a discharge pipe connected to the top of the inner cavity, and the bottom of the inner cavity is a high-density pure phase, which can be discharged through a discharge pipe connected to the bottom of the inner cavity. The whole process can be carried out continuously.

[0043] Further, in the embodiment of the present application, both the upper multi-stage baffle assembly and the lower multi-stage baffle assembly include a plurality of baffles alternately arranged on both sides of the inner cavity from top to bottom, and each baffle is arranged obliquely relative to the horizontal plane. In this way, the feed liquid entering the inner cavity through the feed pipe can be demulsified under the action of the baffle after being fully mixed and reacted under the action of the stirring assembly 30, and can be stratified in the relatively stable environment formed by the multi-stage baffle assembly, thereby effectively separating the two phases with different densities, ensuring that the pure phase with relatively low density is located at the top of the inner cavity, and the pure phase with relatively high density is located at the bottom of the inner cavity, and then the two phases are discharged separately through the discharge pipes located at the top and bottom, respectively, to achieve automatic separation. Among them, the number of baffles can be set as needed, and the spacing between adjacent baffles can be determined according to the volume of the inner cavity, and a relatively uniform distribution mode can be presented as a whole. The number of upper multi-stage baffles and lower multi-stage baffles is preferably three respectively. In the case of severe emulsification and slow stratification, the number of upper and lower baffles can be appropriately increased to achieve a better stratification effect while saving space.

[0044] Furthermore, in the embodiment of the present application, the angle between each partition and the horizontal plane is preferably 10 to 20°, and the area of ​​each partition accounts for 85% to 95% of the cross-sectional area of ​​the inner cavity. Among them, if the angle between the partition and the horizontal plane is too large, not only will it occupy more space, but it will also affect the reaction; if the angle between the partition and the horizontal plane is too small or the area of ​​the partition is too small, it will affect the stratification effect, resulting in mixing of the two phases and difficulty in obtaining a pure phase. The embodiment of the present application controls the angle between the partition and the horizontal plane and the area of ​​the partition, so as to ensure the effective stratification of two phases with different densities with a smaller occupied space and improve the automatic stratification effect.

[0045] Furthermore, if Figure 1 As shown, in the embodiment of the present application, the upper multi-stage baffle assembly includes a first baffle 41, a second baffle 42 and a third baffle 43 which are alternately arranged on both sides of the inner cavity from top to bottom; the first baffle 41 is arranged downwardly tilted from the side where the discharge pipe at the top of the inner cavity is located, the second baffle 42 is arranged upwardly tilted from the opposite side of the discharge pipe at the top of the inner cavity, and the third baffle 43 is arranged upwardly tilted from the side where the discharge pipe at the top of the inner cavity is located; the lower multi-stage baffle assembly includes a fourth baffle 44, a fifth baffle 45 and a sixth baffle 46 which are alternately arranged on both sides of the inner cavity from top to bottom; the sixth baffle 46 is arranged upwardly tilted from the side where the discharge pipe at the bottom of the inner cavity is located, the fifth baffle 45 is arranged downwardly tilted from the opposite side of the discharge pipe at the bottom of the inner cavity, and the fourth baffle 44 is arranged downwardly tilted from the side where the discharge pipe at the bottom of the inner cavity is located. With such an arrangement, the two phases with different densities can be automatically separated by using the multi-stage baffles and their tilting directions when the stirring assembly 30 is continuously running.

[0046] Specifically, taking the alkali washing kettle 10 as an example, when the alkali washing kettle 10 is filled with solution and the stirring component 30 is continuously running, the alkali washing liquid and the crude product of the benzoic acid ester reaction synthesized by the esterification method are input into the alkali washing kettle 10 through the alkali washing feed pipe connected to the middle part of the alkali washing kettle 10, so that the alkali in the alkali washing liquid and the benzoic acid in the crude product of the benzoic acid ester reaction are quickly mixed under the action of the stirring component 30 for neutralization reaction, and the generated salt, water and unreacted alkali liquid are dissolved to form an aqueous phase, and the benzoic acid ester serves as an oil phase, and the density of the oil phase is lower than that of the aqueous phase. The two phases are mixed with each other under the stirring action, and break the emulsion when hitting the third partition plate 43 and the fourth partition plate 44, and gradually separate into layers.

[0047] Under the action of the upper multi-stage partition assembly, the oil phase continuously floats up along the inclined direction of the third partition 43 and enters between the third partition 43 and the second partition 42. The two partitions with a larger area effectively isolate the disturbance effect of the stirring assembly 30, and the two-phase mixture can be gradually stratified here. The water phase mixed in the mixture sinks along the first partition 41 and is deposited at the corner between the upper surface of the first partition 41 and the inner wall of the alkali washing kettle 10. The oil phase further floats up along the inclined direction of the second partition 42 and enters between the second partition 42 and the first partition 41. The interference of the stirring assembly 30 here is further reduced, which can further promote the stratification of the mixed phase. A small amount of water phase is deposited on the upper surface of the second partition 42 and the corner of the inner wall of the alkali washing kettle 10, so that the liquid phase entering the top of the first partition 41 is all oil phase, thereby discharging the automatically separated oil phase through the alkali washing crude product discharge pipe 11 at the top of the inner cavity. Under the action of the lower partition assembly, the water phase continues to sink along the inclined direction of the fourth partition 44 and enters between the fourth partition 44 and the fifth partition 45, where it is less affected by the stirring assembly 30, and the mixture is further stratified. A small amount of oil phase mixed in the mixture floats along the fourth partition 44 and gathers at the corner between the lower surface of the fourth partition 44 and the inner wall of the alkali washing kettle 10. The water phase further sinks along the inclined direction of the fifth partition 45 and enters between the fifth partition 45 and the sixth partition 46. Here, the interference of the stirring assembly 30 is further reduced, which can further promote the stratification of the mixed phase. A small amount of oil phase gathers at the corner between the lower surface of the fifth partition 45 and the inner wall of the alkali washing kettle 10, so that the liquid phase entering the bottom of the sixth partition 46 is all water phase, and the automatically separated water phase is discharged through the alkali washing wastewater discharge pipe 12 at the bottom of the inner cavity.

[0048] Similarly, the multi-stage oil-water separation device in the water washing kettle 20 can also achieve the above effect. When the water washing kettle 20 is filled with solution and the stirring assembly 30 is continuously running, clean water and alkali-washed crude product are input into the water washing kettle 20 through the water washing feed pipe connected to the middle of the water washing kettle 20, so that the trace alkali and salt mixed in the alkali-washed crude product are fully dissolved in the clean water to form a water phase, and benzoic acid ester is still used as the oil phase. At this time, the density of the oil phase is higher than the density of the water phase. The two phases are fully mixed under the stirring action, and when they hit the third partition plate 43 and the fourth partition plate 44, they break the emulsion and gradually separate. Under the action of the upper multi-stage partition assembly, the water phase continuously floats up along the inclined direction of the third partition 43 and enters between the third partition 43 and the second partition 42. The two-phase mixture can be gradually stratified here, and the oil phase mixed in the mixture sinks along the first partition 41 and is deposited at the corner between the upper surface of the first partition 41 and the inner wall of the washing kettle 20. The water phase further floats up along the inclined direction of the second partition 42 and enters between the second partition 42 and the first partition 41, where it is further stratified. The stratified oil phase is deposited at the corner between the upper surface of the second partition 42 and the inner wall of the washing kettle 20, so that the liquid phase entering the top of the first partition 41 is all water phase, and the automatically separated water phase is discharged through the water washing wastewater discharge pipe 21 at the top of the inner cavity. Under the action of the lower multi-stage partition assembly, the oil phase continues to sink along the inclined direction of the fourth partition 44 and enters between the fourth partition 44 and the fifth partition 45, and the mixture is further stratified. The water phase mixed in the mixture floats along the fourth partition 44 and gathers at the corner between the lower surface of the fourth partition 44 and the inner wall of the water washing kettle 20. The oil phase further sinks along the inclined direction of the fifth partition 45 and enters between the fifth partition 45 and the sixth partition 46, further promoting the stratification of the mixed phase. The stratified water phase gathers at the corner between the lower surface of the fifth partition 45 and the inner wall of the water washing kettle 20, so that the liquid phase entering the bottom of the sixth partition 46 is all oil phase, and the oil phase after automatic separation is discharged through the water-washing crude product discharge pipe 22 at the bottom of the inner cavity.

[0049] Further, in the embodiment of the present application, the stirring assembly 30 includes a stirring shaft and a stirring blade connected to the stirring shaft. The stirring blade is arranged between the upper baffle assembly and the lower baffle assembly and is located at a position corresponding to the feed pipe so as to effectively stir the feed and make it fully mixed. The stirring shaft can be driven by a motor or other driving mechanism, and the stirring shaft can be horizontally arranged, vertically arranged or tilted as needed. When the stirring shaft is arranged vertically, it can pass through each baffle in the upper baffle assembly or the lower baffle assembly.

[0050] Further, in the embodiment of the present application, the alkali washing crude product discharge pipeline 11, the alkali washing wastewater discharge pipeline 12, the alkali washing feed pipeline, the water washing wastewater discharge pipeline 21, the water washing crude product discharge pipeline 22, and the water washing feed pipeline are all provided with flow control components; the flow control component includes a control valve 50 and a mass flow meter 60. With such a configuration, the mass flow of the corresponding pipeline can be accurately controlled by adjusting the opening and closing degree of the control valve 50, so as to achieve that the quality of the feed liquid input into the alkali washing kettle 10 and the water washing kettle 20 is basically consistent with the quality of the corresponding feed liquid discharged, and ensure that the ratio of oil to water in the alkali washing kettle 10 and the water washing kettle 20 is always controlled at a level close to 1:1.

[0051] Furthermore, in the embodiment of the present application, a first online density meter 71 is provided at the upper part of the inner cavity, and a second online density meter 72 is provided at the lower part of the inner cavity. With such a configuration, the density of the solution at the upper and lower parts of the inner cavity can be monitored in real time, so as to check whether the automatic stratification effect of the device and the flow distribution of the upper and lower discharge ports are appropriate. According to the corresponding density detection results, the regulation of the corresponding control valve 50 can be further guided, so that the material in the kettle always maintains a ratio of oil to water close to 1:1, ensuring the alkali washing and water washing efficiency and the oil-water stratification effect of the device.

[0052] Furthermore, in the embodiment of the present application, the first online density meter 71 is arranged on the side where the second partition 42 is connected to the inner cavity, and its height is between the highest point of the second partition 42 and the lowest point of the first partition 41; the second online density meter 72 is arranged on the side where the fifth partition 45 is connected to the inner cavity, and its height is between the lowest point of the fifth partition 45 and the highest point of the sixth partition 46. In this way, when the detection result of the corresponding online density meter meets the requirements, it can be ensured that the discharged liquid phase meets the requirements; when the detection result of the corresponding online density meter begins to have problems, it indicates that the liquid phase above the first partition 41 and below the sixth partition 46 temporarily meets the requirements at this moment, and by adjusting the opening and closing degree of the corresponding control valve 50, it is still in time to make adjustments to ensure that the final output crude product meets the requirements.

[0053] Further, in the embodiment of the present application, the alkali washing feed pipeline includes an alkali liquid feed pipeline 13 and a reaction crude product feed pipeline 14; the connection port between the alkali liquid feed pipeline 13 and the alkali washing kettle 10 is located above the connection port between the reaction crude product feed pipeline 14 and the alkali washing kettle 10. The water washing feed pipeline includes a clean water feed pipeline 23 and an alkali washing crude product feed pipeline 24, and the alkali washing crude product feed pipeline 24 is connected to the alkali washing crude product discharge pipeline 11; the connection port between the clean water feed pipeline 23 and the water washing kettle 20 is located below the connection port between the alkali washing crude product feed pipeline 24 and the water washing kettle 20. Corresponding control valves 50 and mass flow meters 60 can be respectively provided in the alkali liquid feed pipeline 13, the reaction crude product feed pipeline 14, the clean water feed pipeline 23 and the alkali washing crude product feed pipeline 24. Such an arrangement makes it easy to regulate the flow rate of each feed pipe separately; on this basis, by setting the feed pipe of the liquid phase with relatively higher density at a relatively higher position and the feed pipe of the liquid phase with relatively lower density at a relatively lower position, it is more conducive to promoting sufficient mixing and reaction of the two.

[0054] By the above method, the flow rate can be accurately controlled by adjusting the control valve 50 corresponding to each pipeline, and the control effect can be checked in combination with the corresponding density meter to adjust in time. In some embodiments of the present application, if the content of benzoic acid in the crude product of benzoate reaction is known in advance, the theoretical alkali washing wastewater discharge quality and the alkali washing crude product discharge quality after full reaction can be calculated according to the feed quality of the crude product of reaction and the feed amount of alkali solution, and then the mass flow rate of the corresponding pipeline is made to meet the requirements by adjusting the corresponding control valve 50. If the content of benzoic acid in the crude product of benzoate reaction is not known in advance, the alkali solution feed quality can be simply controlled to be consistent with the alkali washing wastewater discharge quality, the reaction crude product feed quality is consistent with the alkali washing crude product discharge quality, the alkali washing crude product feed quality, and the water washing crude product discharge quality, and the clean water feed quality is consistent with the water washing wastewater discharge quality. However, due to the presence of a certain amount of benzoic acid in the crude product of the benzoate reaction, simply controlling the quality of the corresponding materials to be consistent in the input and output will result in a certain error. This error can be ignored in a short-term operation, but the gradually accumulated error may have an impact in a long-term operation. At this time, the corresponding control method can be adjusted according to the detection result of the density meter. For example, when the density in the first online density meter 71 is detected to be too high, it indicates that the residual amount of alkali washing wastewater is too high. At this time, the discharge quality of the alkali washing wastewater can be increased and the discharge quality of the alkali washing crude product can be reduced, so as to quickly discharge the excess alkali washing wastewater; if the discharge quality of the alkali washing wastewater is too much, it will cause the second online density meter 72 to measure a low density. At this time, the corresponding control valve 50 can be adjusted to reduce the discharge quality of the alkali washing wastewater and increase the discharge quality of the alkali washing crude product. Based on the joint action of the control valve 50, the flow meter and the density meter, the input and output conditions of the alkali washing kettle 10 and the water washing kettle 20 can be effectively regulated to achieve fully automatic continuous alkali washing, water washing and discharging.

[0055] In a second aspect, the present application also provides a method for continuous alkaline washing and water washing of benzoic acid esters, using the device provided in the above embodiment, comprising the following steps:

[0056] The alkali washing liquid and the crude product of the benzoic acid ester reaction synthesized by the esterification method are fed into the alkali washing kettle 10 through the alkali washing feed pipe, and the stirring component 30 in the alkali washing kettle 10 is turned on to perform alkali washing under stirring. The alkali washing wastewater and the alkali washing crude product generated during the alkali washing process are automatically separated and discharged through the alkali washing wastewater discharge pipe 12 and the alkali washing crude product discharge pipe 11 respectively; during the alkali washing process, the alkali washing kettle 10 is always full of liquid phase;

[0057] Clean water and alkali-washed crude product are fed into the washing kettle 20 through the washing feed pipe, and the stirring assembly 30 in the washing kettle 20 is turned on to perform water washing under stirring. The washing wastewater and the washing crude product generated during the washing process are automatically separated and discharged through the washing wastewater discharge pipe 21 and the washing crude product discharge pipe 22 respectively; during the washing process, the washing kettle 20 is always filled with liquid phase.

[0058] In the technical scheme of the embodiment of the present application, by adopting a device for continuous alkali washing and water washing of benzoic acid ester, the alkali washing liquid and the crude product of benzoic acid ester can be continuously input into the alkali washing kettle 10 at a given mass flow rate while keeping the stirring assembly 30 continuously running, so that it can fully react and automatically stratify in the alkali washing kettle 10, and the alkali washing wastewater and the alkali washing crude product are continuously discharged through the alkali washing wastewater discharge pipe 12 at the bottom and the alkali washing crude product discharge pipe 11 at the top, respectively, without pausing stirring and waiting for static stratification. Similarly, the discharged alkali washing crude product enters the water washing kettle 20 again, and is continuously added and fully mixed with the clean water of the set mass flow rate, and is automatically stratified, and then the washing wastewater and the washing crude product are continuously discharged through the washing wastewater discharge pipe 21 at the top and the washing crude product discharge pipe 22 at the bottom, respectively, and the entire feeding, alkali washing, water washing, and discharging process can be continuously and fully automatic, and the operation is convenient and easy to control. The whole process does not require manual on-site observation, monitoring and operation, and can meet the needs of practical applications. In the initial state, the control valve 50 of each discharge pipe can be closed to continuously feed to ensure that the alkali washing kettle 10 and the water washing kettle 20 are full of liquid phase. Thereafter, the control valve 50 of the discharge pipe can be opened to control the total amount of feed to be consistent with the total amount of discharge so that the alkali washing kettle 10 and the water washing kettle 20 are always kept full of liquid phase, and the whole process can be carried out continuously.

[0059] Some specific embodiments are listed below. It should be noted that the embodiments described below are exemplary and are only used to explain the present application, and should not be construed as limiting the present application.

[0060] Example 1

[0061] This embodiment provides a device for continuous alkaline washing and water washing of benzoic acid esters, the structural schematic diagram of the device is shown in Figure 1 As shown, it includes an alkali washing device and a water washing device; the alkali washing device includes an alkali washing kettle 10, an alkali washing crude product discharge pipe 11 connected to the top of the alkali washing kettle 10, an alkali washing wastewater discharge pipe 12 connected to the bottom of the alkali washing kettle 10, an alkali liquid feed pipe 13 and a reaction crude product feed pipe 14 connected to the side wall of the alkali washing kettle 10, and the connecting port of the alkali liquid feed pipe 13 and the alkali washing kettle 10 is located above the connecting port of the reaction crude product feed pipe 14 and the alkali washing kettle 10; the water washing device includes a water washing The kettle 20, a water washing wastewater discharge pipe 21 connected to the top of the water washing kettle 20, a water washing crude product discharge pipe 22 connected to the bottom of the water washing kettle 20, a clean water feed pipe 23 and an alkali washing crude product feed pipe 24 connected to the side wall of the water washing kettle 20 and the alkali washing crude product discharge pipe 11, the alkali washing crude product feed pipe 24 is connected to the alkali washing crude product discharge pipe 11, and the connecting port of the clean water feed pipe 23 and the water washing kettle 20 is located below the connecting port of the alkali washing crude product feed pipe 24 and the water washing kettle 20. Among them, the inner cavity of the alkali washing kettle 10 and the water washing kettle 20 are both provided with a multi-stage oil-water stratification device, and the structures of the multi-stage oil-water stratification devices in the inner cavity of the alkali washing kettle 10 and the water washing kettle 20 are completely consistent. The multi-stage oil-water stratification device includes a stirring assembly 30 arranged in the middle of the inner cavity and an upper multi-stage baffle assembly and a lower multi-stage baffle assembly respectively arranged at the upper and lower parts of the inner cavity.

[0062] The upper multi-stage baffle assembly includes a first baffle 41, a second baffle 42 and a third baffle 43 which are alternately arranged on both sides of the inner cavity from top to bottom; the first baffle 41 is arranged downwardly at an angle of 12° from the side where the discharge pipe at the top of the inner cavity is located, the second baffle 42 is arranged upwardly at an angle of 12° from the opposite side of the discharge pipe at the top of the inner cavity, and the third baffle 43 is arranged upwardly at an angle of 12° from the side where the discharge pipe at the top of the inner cavity is located; the lower multi-stage baffle assembly includes a fourth baffle 44, a fifth baffle 45 and a sixth baffle 46 which are alternately arranged on both sides of the inner cavity from top to bottom; the sixth baffle 46 is arranged upwardly at an angle of 12° from the side where the discharge pipe at the bottom of the inner cavity is located, the fifth baffle 45 is arranged downwardly at an angle of 12° from the opposite side of the discharge pipe at the bottom of the inner cavity, and the fourth baffle 44 is arranged downwardly at an angle of 12° from the side where the discharge pipe at the bottom of the inner cavity is located. The area of ​​each baffle occupies 92% of the cross-sectional area of ​​the inner cavity. The stirring assembly 30 includes a stirring shaft and stirring blades connected to the stirring shaft. The stirring blades are arranged between the upper partition assembly and the lower partition assembly and are located at a position corresponding to the feed pipe. The stirring shaft is driven by a motor and passes through the first partition 41, the second partition 42 and the third partition 43.

[0063] A control valve 50 and a mass flowmeter 60 are provided in the alkali liquor feed pipeline 13, the reaction crude product feed pipeline 14, the alkali washing crude product discharge pipeline 11, the alkali washing wastewater discharge pipeline 12, the clean water feed pipeline 23, the alkali washing crude product feed pipeline 24, the water washing wastewater discharge pipeline 21, and the water washing crude product discharge pipeline 22. In this embodiment, the residual benzoic acid content in the benzoic acid ester is 1%, the mass flow rate entering the alkali liquor feed pipeline 13 is set to 20kg / h, the alkali liquor is 5% sodium hydroxide solution, the mass flow rate entering the reaction crude product feed pipeline 14 is set to 20kg / h, and the mass flow rate of the alkali washing wastewater discharge pipeline 22 is controlled to be 20.2kg / h. The mass flow rate of the clean water feed pipeline 23 is set to 20kg / h, and the mass flow rate of the water washing wastewater discharge pipeline 21 is set to 20kg / h. The first online density meter 71 and the second online density meter 72 are respectively arranged at the upper and lower parts of the inner cavity; the first online density meter 71 is arranged on the side where the second partition 42 is connected to the inner cavity, and its height is between the highest point of the second partition 42 and the lowest point of the first partition 41; the second online density meter 72 is arranged on the side where the fifth partition 45 is connected to the inner cavity, and its height is between the lowest point of the fifth partition 45 and the highest point of the sixth partition 46.

[0064] Based on the above device, this embodiment also provides a method for continuous alkali washing and water washing of benzoic acid esters, comprising the following steps:

[0065] In the initial state, the stirring assembly 30 is turned on, the control valves 50 of the alkali-washed crude product discharge pipe 11 and the alkali-washed wastewater discharge pipe 12 are closed, the control valves 50 of the alkali liquor feed pipe 13 and the reaction crude product feed pipe 14 are opened, and the alkali-washed kettle 10 is continuously fed until the alkali-washed kettle 10 is filled with liquid phase. After the oil and water in the alkali-washed kettle 10 are separated, the alkali liquor feed pipe 13 and the reaction crude product feed pipe 14 are continuously fed into the alkali-washed kettle 10, and the control valves 50 of the alkali-washed crude product discharge pipe 11, the alkali-washed wastewater discharge pipe 12, the alkali-washed crude product feed pipe 24, and the clean water feed pipe 23 are opened at the same time, so that the alkali liquor can fully react with the benzoic acid in the reaction crude product under the action of the stirring assembly 30, and realize automatic separation under the action of the partition, so that the alkali-washed wastewater and the alkali-washed crude product are discharged through the alkali-washed wastewater discharge pipe 12 and the alkali-washed crude product discharge pipe 11 respectively. In this process, the opening of the corresponding control valve 50 is adjusted so that the mass flow rate of the corresponding pipeline meets the set requirements, so that the discharge quality of the alkali washing waste liquid is basically consistent with the feed quality of the alkali washing waste liquid and the total mass of benzoic acid in the crude reaction product, and ensure that the alkali washing kettle 10 is always full of liquid phase.

[0066] The alkali-washed crude product discharged from the alkali-washed crude product discharge channel enters the alkali-washed crude product feed pipe 24 through the connecting pipe, enters the water washing kettle 20 together with the clean water input from the clean water feed pipe 23, and is fully mixed under the action of the stirring component 30. In the initial state, the water washing wastewater discharge pipe 21 and the water washing crude product discharge pipe 22 are closed first, until the alkali-washed crude product and the clean water fill the water washing kettle 20. Then, the water washing wastewater discharge pipe 21 and the water washing crude product discharge pipe 22 are opened, and the alkali-washed crude product and the clean water are continuously input, so that the clean water and the alkali-washed crude product are fully mixed under the action of the stirring component 30 for water washing, and the water washing wastewater and the water washing crude product generated during the water washing process are automatically layered and discharged through the water washing wastewater discharge pipe 21 and the water washing crude product discharge pipe 22, respectively. In this process, by adjusting the opening of the corresponding control valve 50, the mass flow rate of the corresponding pipeline meets the set requirements, so that the quality of the alkali washing crude product feed is basically consistent with the quality of the water washing crude product discharge, and the quality of the clean water feed is consistent with the quality of the water washing wastewater discharge, ensuring that the water washing kettle 20 is always full of liquid phase.

[0067] In the above manner, alkali washing and water washing can be performed continuously, and the stirring assembly 30 can operate continuously without pausing to wait for static stratification. When alkali washing and water washing are performed for a long time, the values ​​of the first online density meter 71 and the second online density meter 72 can be continuously monitored. When an abnormality occurs, the discharge quality can be regulated by adjusting the opening of the control valve 50 on each discharge pipe to ensure that the discharged product meets the requirements and the material in the kettle always maintains an oil-water ratio close to 1:1, ensuring the alkali washing and water washing efficiency and oil-water stratification effect of the device.

[0068] After inspection, the washed crude product finally outputted in this embodiment did not separate into layers after standing still, but was a single pure phase.

[0069] Comparative Example 1

[0070] This comparative example provides an apparatus and method for continuous alkaline washing and water washing of benzoic acid esters. Compared with Example 1, the only difference is that all six partitions are set to a horizontal layout. The remaining structures and corresponding operating steps are consistent with Example 1 and will not be repeated here.

[0071] Upon inspection, the washed crude product finally outputted from this comparative example was separated into layers after standing, indicating that a water phase was mixed therein and effective oil-water separation was not achieved.

[0072] Comparative Example 2

[0073] This comparative example provides an apparatus and method for continuous alkaline washing and water washing of benzoic acid esters. Compared with Example 1, the only difference is that the number of partitions is changed. In this comparative example, the upper partition assembly only contains the first partition 41, and the lower partition assembly only contains the fourth partition 44. The remaining structures and corresponding operating steps are consistent with Example 1 and will not be repeated here.

[0074] Upon inspection, the washed crude product finally outputted from this comparative example was separated into layers after standing, indicating that a water phase was mixed therein and effective oil-water separation was not achieved.

[0075] Example 2

[0076] The present embodiment provides an apparatus and method for continuous alkali washing of benzoic acid esters. Compared with Example 1, the only difference is that the mass flow rates of the alkali solution feed pipeline 13, the reaction crude product feed pipeline 14 and the alkali washing wastewater discharge pipeline 12 are changed. In the present embodiment, the feed rate of the alkali solution feed pipeline 13 is set to 10 kg / h, the feed rate of the reaction crude product feed pipeline 14 is set to 20 kg / h, and the discharge rate of the alkali washing wastewater discharge pipeline 12 is set to 10.2 kg / h. The remaining structures and corresponding operating steps are consistent with those in Example 1 and are not repeated here.

[0077] After inspection, the washed crude product finally outputted in this embodiment did not separate into layers after standing, and was a single pure phase. Compared with Example 1, it can be seen that based on the device and method provided by this application, the flow rates of each pipeline can be adjusted accordingly according to actual needs while ensuring that the oil-water ratio in the kettle remains basically unchanged, and both can achieve a good oil-water separation effect.

[0078] In summary, the present application provides a device and method for continuous alkali washing and water washing of benzoic acid esters. The device includes an alkali washing device and a water washing device, the alkali washing device includes an alkali washing kettle 10, an alkali washing crude product discharge pipe 11 connected to the top of the alkali washing kettle 10, an alkali washing wastewater discharge pipe 12 connected to the bottom of the alkali washing kettle 10, and an alkali washing feed pipe connected to the side wall of the alkali washing kettle 10; the water washing device includes a water washing kettle 20, a water washing wastewater discharge pipe 21 connected to the top of the water washing kettle 20, a water washing crude product discharge pipe 22 connected to the bottom of the water washing kettle 20, and a water washing feed pipe connected to the side wall of the water washing kettle 20 and the alkali washing crude product discharge pipe 11; the inner cavities of the alkali washing kettle 10 and the water washing kettle 20 are both provided with a multi-stage oil-water stratification device, including a stirring assembly 30 arranged in the middle of the inner cavity and a multi-stage baffle assembly respectively arranged at the upper and lower parts of the inner cavity. The device can ensure that the raw materials are fully mixed and reacted while achieving automatic stratification of liquids with different densities, so that the processes of feeding, alkali washing, water washing and discharging of benzoic acid esters can be carried out continuously.

[0079] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and the embodiments having the same structure as the technical idea and exerting the same effect within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, without departing from the scope of the main purpose of the present application, various modifications that can be thought of by those skilled in the art to the embodiments and other methods of combining some of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A device for continuous alkaline washing and water washing of benzoic acid esters, characterized in that: It includes an alkali washing device and a water washing device; The alkali washing device comprises an alkali washing kettle, an alkali washing crude product discharge pipe connected to the top of the alkali washing kettle, an alkali washing wastewater discharge pipe connected to the bottom of the alkali washing kettle, an alkali washing feed pipe connected to the side wall of the alkali washing kettle and corresponding flow control components; The water washing device comprises a water washing kettle, a water washing wastewater discharge pipe connected to the top of the water washing kettle, a water washing crude product discharge pipe connected to the bottom of the water washing kettle, a water washing feed pipe connected to the side wall of the water washing kettle and the alkali washing crude product discharge pipe, and corresponding flow control components; The inner cavities of the alkaline washing kettle and the water washing kettle are both provided with a multi-stage oil-water stratification device; the multi-stage oil-water stratification device comprises a stirring assembly arranged in the middle of the inner cavity and an upper multi-stage baffle assembly and a lower multi-stage baffle assembly respectively arranged in the upper and lower parts of the inner cavity.

2. The device for continuous alkali washing and water washing of benzoic acid esters according to claim 1, characterized in that: The upper multi-stage baffle assembly and the lower multi-stage baffle assembly both include a plurality of baffles alternately arranged on both sides of the inner cavity from top to bottom; the baffles are inclined at a certain angle relative to the horizontal plane.

3. The device for continuous alkali washing and water washing of benzoic acid esters according to claim 2 is characterized in that: The included angle between the partition and the horizontal plane is 10-20 degrees, and the area of ​​the partition accounts for 85%-95% of the cross-sectional area of ​​the inner cavity.

4. The device for continuous alkali washing and water washing of benzoic acid esters according to claim 1 is characterized in that: The upper multi-stage baffle assembly includes a first baffle, a second baffle and a third baffle alternately arranged on both sides of the inner cavity from top to bottom; the first baffle is arranged to be tilted downward from the side where the discharge pipe at the top of the inner cavity is located, the second baffle is arranged to be tilted upward from the opposite side of the discharge pipe at the top of the inner cavity, and the third baffle is arranged to be tilted upward from the side where the discharge pipe at the top of the inner cavity is located.

5. The device for continuous alkali washing and water washing of benzoic acid esters according to claim 4 is characterized in that: The lower multi-stage partition assembly includes a fourth partition, a fifth partition and a sixth partition alternately arranged on both sides of the inner cavity from top to bottom; the sixth partition is arranged to tilt upward from the side where the discharge pipe at the bottom of the inner cavity is located, the fifth partition is arranged to tilt downward from the opposite side of the discharge pipe at the bottom of the inner cavity, and the fourth partition is arranged to tilt downward from the side where the discharge pipe at the bottom of the inner cavity is located.

6. The device for continuous alkali washing and water washing of benzoic acid esters according to claim 1 is characterized in that: The flow control component is arranged in the alkali washing crude product discharge pipe, the alkali washing wastewater discharge pipe, the alkali washing feed pipe, the water washing wastewater discharge pipe, the water washing crude product discharge pipe and the water washing feed pipe; the flow control component comprises a control valve and a mass flow meter.

7. The device for continuous alkali washing and water washing of benzoic acid esters according to claim 5, characterized in that: An online density meter is disposed between the first separator and the second separator, and between the fifth separator and the sixth separator, respectively.

8. The device for continuous alkali washing and water washing of benzoic acid esters according to claim 1 is characterized in that: The alkali washing feed pipeline comprises an alkali solution feed pipeline and a reaction crude product feed pipeline; the connecting port between the alkali solution feed pipeline and the alkali washing kettle is located above the connecting port between the reaction crude product feed pipeline and the alkali washing kettle.

9. The device for continuous alkali washing and water washing of benzoic acid esters according to claim 1, characterized in that: The water washing feed pipeline includes a clean water feed pipeline and an alkali washing crude product feed pipeline, and the alkali washing crude product feed pipeline is connected to the alkali washing crude product discharge pipeline; the connecting port between the clean water feed pipeline and the water washing kettle is located below the connecting port between the alkali washing crude product feed pipeline and the water washing kettle.

10. A method for continuously washing benzoic acid esters with alkali washing, characterized in that: The device according to any one of claims 1 to 9 comprises the following steps: The alkali washing liquid and the crude product of the benzoic acid ester reaction synthesized by the esterification method are fed into the alkali washing kettle through the alkali washing feed pipe, and the stirring component in the alkali washing kettle is turned on to perform alkali washing under stirring. The alkali washing wastewater and the alkali washing crude product oil-water two phases generated during the alkali washing process are separated into oil and water phases under the action of the multi-stage partition plate and discharged through the alkali washing wastewater discharge pipe and the alkali washing crude product discharge pipe respectively; during the alkali washing process, the alkali washing kettle is always filled with liquid phase; Clean water and the alkali-washed crude product are fed into the washing kettle through the washing feed pipe, and the stirring component in the washing kettle is turned on to perform water washing under stirring. The washing wastewater and the washing crude product generated during the washing process are separated into oil and water layers under the action of multi-stage partitions and discharged through the washing wastewater discharge pipe and the washing crude product discharge pipe respectively; during the washing process, the washing kettle is always filled with liquid phase.

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