Continuous separation and concentration device and method for alkyl oxalate catalyst

Abstract

The invention provides a continuous separation and concentration device and method for an alkyl oxalate catalyst, and belongs to the technical field of solid-liquid separation. The continuous separation and concentration device comprises a shell, a cyclone separation assembly and a dead end filtering assembly; the interior of the shell is divided into a gas phase space, a liquid phase space and a settling space from top to bottom; the cyclone separation assembly is arranged in the liquid phase space of the shell; feed liquid in the cyclone separation assembly enters the liquid phase space from the top, and a catalyst in the cyclone separation assembly enters the settling space from the bottom; the dead end filtering assembly is arranged in the liquid phase space and located around the cyclone separation assembly or located above the cyclone separation assembly; wherein the feeding amount of the cyclone separation assembly is equal to the sum of the discharge amount of filtered clear liquid of secondary filtration and the discharge amount of a catalyst, so that the liquid level in the liquid phase space is kept stable, and the continuous separation and concentration process is realized; by means of the device, secondary separation is conducted on mixed liquid, the continuous separation and concentration process can be achieved, and precise extraction of oxalic acid alkyl ester can be achieved.

Description

Technical Field

[0001] The present application belongs to the field of solid-liquid separation technology, and specifically relates to a device and method for continuous separation and concentration of an alkyl oxalate catalyst. Background Art

[0002] Alkyl oxalate is an important organic chemical raw material and methylation / ethylation reagent, which can undergo various condensation reactions with fatty acid esters, amides or aniline compounds and many heterocyclic compounds; as an asymmetric alkyl oxalate, it can be used as a lithium battery electrolyte solvent.

[0003] In the production process of alkyl oxalate, alcohol raw materials and ester raw materials undergo esterification reaction under the action of solid catalyst to produce alkyl oxalate; by filtering the solid-liquid mixture, the alkyl oxalate can be filtered out, and the remaining solid catalyst can continue to be mixed with the alcohol raw materials and ester raw materials to play a catalytic role.

[0004] When ceramic membrane cross-flow filtration is used to separate alkyl oxalate and solid catalyst, the initial flux of the ceramic membrane is small, the flux decays quickly, the concentration ratio is low, and the catalyst is severely worn and damaged, which affects the subsequent catalytic effect of the catalyst.

[0005] When the separation of alkyl oxalate and solid catalyst is carried out by centrifugation, the separation accuracy cannot meet the requirements and a large amount of small-particle catalyst cannot be intercepted, resulting in a large amount of catalyst waste. Summary of the Invention

[0006] The embodiments of the present application provide an apparatus and method for continuous separation and concentration of an alkyl oxalate catalyst, which aims to achieve precise recovery of alkyl oxalate and reduce wear and damage to the solid catalyst.

[0007] To achieve the above objectives, the technical solution adopted in this application is: Provided is a device and method for continuously separating and concentrating an alkyl oxalate catalyst, comprising: The shell is divided into gas phase space, liquid phase space and sedimentation space from top to bottom; A cyclone separation component is disposed in the liquid phase space of the housing, and a feed port of the cyclone separation component is connected to a feed port on the side wall of the housing; the feed liquid in the cyclone separation component enters the liquid phase space from the top, and the catalyst in the cyclone separation component enters the settling space from the bottom, thereby reducing the solid content of the feed liquid in the liquid phase space; The dead-end filter assembly is arranged in the liquid phase space and is located around the cyclone separation assembly, or above the cyclone separation assembly, so as to perform secondary filtration on the liquid separated by the cyclone separation assembly under the action of air pressure; The feed rate of the cyclone separation component is equal to the sum of the discharge rate of the filtered clear liquid from the secondary filtration and the discharge rate of the catalyst, so that the liquid level in the liquid phase space remains stable and a continuous separation and concentration process is achieved.

[0008] In a possible implementation, the dead-end filter assemblies are arranged in groups along the circumference of the shell; the liquid outlet of each dead-end filter assembly is connected to the liquid outlet corresponding to the side wall of the shell.

[0009] In a possible implementation, the cyclone separation assembly includes a plurality of cyclone separators, which are arranged in parallel, and the tops of the cyclone separators are located at the same horizontal plane.

[0010] In one possible implementation, a gas pipeline is provided on the top of the shell, and the gas pipeline is connected to a gas source; wherein, the gas introduced into the shell does not react with the mixed liquid in the shell; the gas in the gas phase space provides pressure to the liquid in the liquid phase space, so that the dead-end filter component performs secondary filtration on the liquid in the liquid phase space.

[0011] In one possible implementation, after the dead-end filter assembly has been running for a preset time, one group of the dead-end filter assemblies is backflushed; after the backflushing of this group of dead-end filters is completed, it is put back into use after an interval of 5-10 minutes to allow the backflushed catalyst filter cake to fully settle to the bottom of the shell.

[0012] In a possible implementation, the shell is in a conical structure at the position of the sedimentation space, with the small end facing downward and provided with a discharge port.

[0013] In a possible implementation, the cone angle of the cone-shaped structure at the bottom of the shell is determined according to the repose angle of the catalyst.

[0014] The present application provides a continuous separation and concentration device and method for an alkyl oxalate catalyst. Compared with the prior art, after a mixed liquid of alkyl oxalate and catalyst is introduced into a cyclone separation assembly, the cyclone separation assembly can perform cyclone separation on the alkyl oxalate and catalyst, so that the feed liquid enters the liquid phase space from the top, and the catalyst settles to the bottom of the cyclone separation assembly and is discharged into the sedimentation space; through the above-mentioned arrangement, the mixed liquid can be separated once, and the solid content in the feed liquid in the liquid phase space can be reduced, thereby extending the operating time of the dead-end filter assembly; under the action of air pressure, the dead-end filter assembly performs a secondary filtration on the feed liquid in the liquid phase space, and the filtered clear liquid is discharged from the shell through the liquid outlet; the above-mentioned process of the present application is a continuous process, which can realize a continuous separation and concentration process; compared with the centrifugal filtration method in the prior art, the above-mentioned arrangement of the present application has a cyclone linear velocity of the mixed liquid of alkyl oxalate and catalyst in the cyclone separation assembly that is lower than the centrifugal linear velocity of the centrifugal filtration method, thereby reducing the wear and damage of the catalyst. In the cross-flow filtration method in the prior art, the mixed liquid flows at high speed in the membrane pores, forming turbulence, and the mutual collisions between the catalysts and the shear collisions with the membrane wall are serious, causing serious damage to the catalysts; the above-mentioned setting of the present application can reduce the scouring of the catalysts, and thus can reduce the wear and damage of the catalysts; through the above-mentioned setting of the present application, the mixed liquid is subjected to secondary separation, which can not only realize the continuous separation and concentration process, but also realize the precise extraction of alkyl oxalate.

[0015] To achieve the above objectives, the technical solution adopted in this application is: A continuous separation and concentration method is provided, comprising the following steps: The mixed liquid of alkyl oxalate and catalyst is passed into the cyclone separation assembly in the shell for cyclone separation. The upper layer of liquid enters the liquid phase space from the top, and the lower layer of catalyst enters the sedimentation space from the bottom, thus completing the preliminary separation in the shell. Under the action of the air pressure in the gas phase space, the dead-end filter assembly filters the liquid in the liquid phase space, and the filtered clear liquid is discharged from the shell from the liquid outlet of the dead-end filter assembly to complete the secondary filtration in the shell; The feed rate of the cyclone separation component is equal to the sum of the discharge rate of the filtered clear liquid and the discharge rate of the catalyst, so that the liquid level in the liquid phase space remains stable and a continuous separation and concentration process is achieved.

[0016] In one possible implementation, there are several groups of dead-end filter assemblies. After running for a preset time, one group of dead-end filter assemblies is backflushed. After the backflushing of this group of dead-end filter assemblies is completed, it is put into use again after an interval of 5-10 minutes to allow the backflushed catalyst filter cake to fully settle to the bottom of the shell.

[0017] In a possible implementation, the concentration ratio can be adjusted by adjusting the discharge rate of the catalyst and the feed rate.

[0018] The beneficial effects of the continuous separation and concentration method provided in this application are the same as those of the continuous separation and concentration device, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of a continuous separation and concentration device for an alkyl oxalate catalyst provided in an embodiment of the present application.

[0020] Explanation of the accompanying symbols: 1. Upper head; 2. Cylinder; 3. Conical cylinder; 4. Feed inlet; 5. Liquid outlet; 6. Discharge port; 7. Gas inlet; 8. Cyclone separation component; 9. Dead-end filter component; I. Gas phase space; II. Cyclone separation and concentration space; III. Liquid phase space; IV. Sedimentation space. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0022] See also Figure 1 Now, a device and method for continuous separation and concentration of alkyl oxalate catalyst provided in this application are described. The invention relates to a continuous separation and concentration device for an alkyl oxalate catalyst, comprising a housing, a cyclone separation assembly 8, and a dead-end filter assembly 9. The interior of the housing is divided from top to bottom into a gas phase space I, a liquid phase space III, and a sedimentation space IV. The cyclone separation assembly 8 is disposed in the liquid phase space III of the housing, and a feed port 4 of the cyclone separation assembly 8 is connected to a feed port 4 on a side wall of the housing. The feed liquid in the cyclone separation assembly 8 enters the liquid phase space III from the top, and the catalyst in the cyclone separation assembly 8 enters the sedimentation space IV from the bottom, thereby reducing the solid content of the feed liquid in the liquid phase space III. The dead-end filter assembly 9 is disposed in the liquid phase space III and is located around or above the cyclone separation assembly 8 to perform secondary filtration on the feed liquid separated by the cyclone separation assembly 8 under the action of air pressure. The feed amount of the cyclone separation assembly 8 is equal to the sum of the discharge amount of the filtered clear liquid and the discharge amount of the catalyst from the secondary filtration, so that the liquid level in the liquid phase space III remains stable, thereby achieving a continuous separation and concentration process.

[0023] The present application provides a continuous separation and concentration device and method for an alkyl oxalate catalyst. Compared with the prior art, after a mixed liquid of alkyl oxalate and catalyst is introduced into a cyclone separation assembly 8, the cyclone separation assembly 8 can perform cyclone separation on the alkyl oxalate and catalyst, so that the feed liquid enters the liquid phase space III from the top, and the catalyst settles to the bottom of the cyclone separation assembly 8 and is discharged into the sedimentation space IV. Through the above-mentioned arrangement, the mixed liquid can be separated once, reducing the solid content in the feed liquid in the liquid phase space III, thereby extending the operating time of the dead-end filter assembly 9. Under the action of air pressure, the dead-end filter assembly 9 performs a secondary filtration on the feed liquid in the liquid phase space III, and the filtered clear liquid is discharged from the shell through the liquid outlet 5. The above-mentioned process of the present application is a continuous process, which can realize a continuous separation and concentration process. Compared with the centrifugal filtration method in the prior art, the above-mentioned arrangement of the present application has a cyclone linear velocity of the mixed liquid of alkyl oxalate and catalyst in the cyclone separation assembly 8 that is lower than the centrifugal linear velocity of the centrifugal filtration method, thereby reducing the wear and damage of the catalyst. In the cross-flow filtration method in the prior art, the mixed liquid flows at high speed in the membrane pores, forming turbulence, and the mutual collision between the catalysts and the shear collision with the membrane wall are serious, causing serious damage to the catalyst; the above-mentioned setting of the present application can reduce the scouring of the catalyst, and thus reduce the wear and damage of the catalyst; through the above-mentioned setting of the present application, the mixed liquid is subjected to secondary separation, which can not only realize the continuous separation and concentration process, but also realize the precise extraction of alkyl oxalate; the particle size of the catalyst particles screened by cyclone separation is <5μm.

[0024] It should be noted that the dead-end filter assembly 9 is arranged around the cyclone separation assembly 8, or above the cyclone separation assembly 8. The main purpose is to allow the dead-end filter assembly 9 to be immersed in the liquid separated by the cyclone separation assembly 8, to avoid the dead-end filter assembly 9 from contacting the catalyst after settling under the shell, and then during the filtration process, to reduce the catalyst accumulation on the membrane element and extend the filtration time of the membrane element.

[0025] In some embodiments, as Figure 1 As shown, a gas conduit is provided at the top of the housing, connected to a gas source. The gas introduced into the housing does not react with the mixed liquid within the housing. The gas within gas phase space I provides pressure to the liquid in liquid phase space III, enabling dead-end filter assembly 9 to perform secondary filtration of the liquid in liquid phase space III. A gas inlet 7 is located at the top of the gas conduit.

[0026] The gas introduced into the shell can be nitrogen. After the nitrogen is introduced into the shell, the nitrogen gathers in the gas phase space I and acts as a thrust on the feed liquid in the liquid phase space III below, so that the feed liquid in the liquid phase space III can pass through the membrane element of the dead-end filter assembly 9, thereby realizing the process of filtering the feed liquid by the dead-end filter assembly 9; through the above-mentioned arrangement, the pressure in the shell can be kept stable by adjusting the liquid level, and this pressure provides a driving force for membrane separation, thereby reducing the impact of pressure fluctuations on the device.

[0027] The gas introduced into the shell does not react with the mixed liquid, which can avoid the generation of other products and further avoid the situation that affects the product quality.

[0028] Exemplarily, the gas phase pressure is 100-600 kPa (G).

[0029] In some embodiments, as Figure 1 As shown, the dead-end filter assemblies 9 are divided into several groups, and the several groups of dead-end filter assemblies 9 are arranged along the circumference of the shell; the liquid outlet 5 of each dead-end filter assembly 9 is connected to the liquid outlet 5 corresponding to the side wall of the shell; after the dead-end filter assembly 9 runs for a preset time, one group of dead-end filter assemblies 9 is backflushed.

[0030] The membrane element in the dead-end filter assembly 9 is a wedge mesh filter element, a sintered metal felt filter element, a sintered metal powder filter element or a sintered metal wire mesh and powder composite filter element; by setting the dead-end filter assembly 9 to several groups, after running for a preset time, one group of the dead-end filter assembly 9 is backflushed, and the remaining dead-end filter assemblies 9 operate normally, thereby ensuring the continuity of filtration.

[0031] In some embodiments, as Figure 1 As shown, the cyclone separation assembly 8 includes a plurality of cyclone separators, which are arranged in parallel and the tops of the cyclone separators are at the same horizontal plane; the interior of the cyclone separator is a cyclone separation and concentration space II.

[0032] By connecting multiple cyclone separators in parallel, the processing capacity can be increased, and a large amount of mixed liquid can be separated in a shorter time, meeting the separation needs of high flow rate. By placing the tops of the cyclone separators at the same horizontal plane, it can be ensured that the mixed liquid has similar initial conditions when entering each cyclone separator, thereby making the separation process uniform and consistent, and improving the stability and reliability of the separation effect.

[0033] In some embodiments, as Figure 1 As shown, after the backflushing of the dead-end filtration group is completed, it is put into use again after an interval of 5-10 minutes to allow the backflushed catalyst filter cake to fully settle to the bottom of the shell.

[0034] Through the above-mentioned setting of the present application, after the backflushing is completed, it is put into use after a period of time, which can prevent the catalyst filter cake recoiled from adhering to the membrane element again, thereby reducing the impact and wear of the catalyst filter cake recoiled on the membrane element, and extending the service life of the membrane element; the catalyst filter cake recoiled is fully settled to the bottom position of the shell, and the concentrated liquid can be discharged through the discharge port 6 at the bottom of the shell.

[0035] In some embodiments, as Figure 1 As shown, the shell is a conical structure at the sedimentation space IV, with the small end facing downward and provided with a discharge port 6; the cone angle of the conical structure at the bottom of the shell is determined according to the repose angle of the catalyst.

[0036] The angle of repose is the maximum angle between the inclined plane formed by the natural accumulation of materials and the horizontal plane, reflecting the fluidity and accumulation characteristics of the material. The cone angle of the conical structure is determined according to the angle of repose of the catalyst, which can ensure the smooth sedimentation process of the catalyst in the shell and reduce the problem of material stagnation or poor flow.

[0037] The settled catalyst and the backwashed catalyst filter cake can be enriched in the settling space IV at the bottom of the shell, making it easy to discharge the catalyst slurry from the bottom of the shell. The discharge process of the catalyst slurry is a continuous process.

[0038] Through the above-mentioned setting of the present application, the separation of heterogeneous alkyl oxalate reaction catalyst is achieved. Compared with multi-stage internal filtration separation, concentration, washing regeneration, and catalyst reuse, the pressure of the device is maintained at a stable value during continuous operation, the device has a large processing capacity, a simple processing flow, and an adjustable concentration ratio.

[0039] The shell includes a cylindrical body 2, an upper head 1 and a conical body 3. The upper head 1 is located at the top of the cylindrical body 2, and the conical body 3 is located at the bottom of the cylindrical body 2.

[0040] Based on the same inventive concept, the present application also provides a continuous separation and concentration method, comprising the following steps: The mixed liquid of alkyl oxalate and catalyst is introduced into the cyclone separation assembly 8 in the shell for cyclone separation. The upper layer of liquid enters the liquid phase space III from the top, and the lower layer of catalyst enters the sedimentation space IV from the bottom to complete the preliminary separation in the shell.

[0041] Under the action of the air pressure in the gas phase space I, the dead-end filter assembly 9 filters the liquid in the liquid phase space III, and the filtered clear liquid is discharged from the shell from the liquid outlet 5 of the dead-end filter assembly 9 to complete the secondary filtration in the shell.

[0042] The feed rate of the cyclone separation component 8 is equal to the sum of the discharge rate of the filtered clear liquid and the discharge rate of the catalyst, so that the liquid level in the liquid phase space III remains stable and a continuous separation and concentration process is achieved.

[0043] In some embodiments, as Figure 1 As shown, the dead-end filter components 9 are divided into several groups. After running for a preset time, one group of the dead-end filter components 9 is backflushed. After the backflushing of the dead-end filter components 9 is completed, it is put into use again after an interval of 5-10 minutes, which can provide sufficient time for the catalyst filter cake backflushed to fully settle to the bottom of the shell.

[0044] In some embodiments, as Figure 1 As shown, since the filtration method of the dead-end filter assembly 9 is surface screening, the catalyst will not be discharged from the dead-end filter assembly 9. Therefore, by adjusting the discharge amount of the catalyst and adjusting the feed amount, the concentration multiple of the catalyst can be controlled to achieve control of the concentration ratio.

[0045] The gas pipeline at the top of the shell, the discharge port 6 at the bottom of the shell, and the feed port 4 and liquid outlet 5 on the side of the shell are all equipped with valves. By adjusting the opening of the valve of the discharge port 6, the discharge amount of the concentrated liquid can be adjusted.

[0046] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A continuous separation and concentration device for an alkyl oxalate catalyst, characterized in that: include: The shell is divided into gas phase space, liquid phase space and sedimentation space from top to bottom; A cyclone separation component is disposed in the liquid phase space of the housing, and a feed port of the cyclone separation component is connected to a feed port on the side wall of the housing; the feed liquid in the cyclone separation component enters the liquid phase space from the top, and the catalyst in the cyclone separation component enters the settling space from the bottom, thereby reducing the solid content of the feed liquid in the liquid phase space; The dead-end filter assembly is arranged in the liquid phase space and is located around the cyclone separation assembly, or above the cyclone separation assembly, so as to perform secondary filtration on the liquid separated by the cyclone separation assembly under the action of air pressure; The feed rate of the cyclone separation component is equal to the sum of the discharge rate of the filtered clear liquid from the secondary filtration and the discharge rate of the catalyst, so that the liquid level in the liquid phase space remains stable and a continuous separation and concentration process is achieved.

2. The device for continuous separation and concentration of alkyl oxalate catalyst according to claim 1, wherein: The dead-end filter components are divided into several groups, and the groups of dead-end filter components are arranged along the circumference of the shell; the liquid outlet of each dead-end filter component is communicated with the liquid outlet corresponding to the side wall of the shell.

3. The device for continuous separation and concentration of alkyl oxalate catalyst according to claim 1, wherein: The cyclone separation assembly includes a plurality of cyclone separators, which are arranged in parallel, and the tops of the cyclone separators are on the same horizontal plane.

4. The device for continuous separation and concentration of alkyl oxalate catalyst according to claim 1, wherein: A gas pipeline is provided on the top of the shell, which is connected to the gas source; wherein the gas introduced into the shell does not react with the mixed liquid in the shell; the gas in the gas phase space provides pressure to the liquid in the liquid phase space, so that the dead-end filter component performs secondary filtration on the liquid in the liquid phase space.

5. The device for continuous separation and concentration of alkyl oxalate catalyst according to claim 2, wherein: After the dead-end filter assembly runs for a preset time, one group of dead-end filter assemblies is backflushed; after the backflushing of this group of dead-end filters is completed, it is put into use again after an interval of 5-10 minutes to allow the backflushed catalyst filter cake to fully settle to the bottom of the shell.

6. The device for continuous separation and concentration of alkyl oxalate catalyst according to claim 1, characterized in that: The shell is in a conical structure at the position of the sedimentation space, with the small end facing downward and provided with a discharge port.

7. The device for continuous separation and concentration of alkyl oxalate catalyst according to claim 6, characterized in that: The cone angle of the cone-shaped structure at the bottom of the shell is determined according to the repose angle of the catalyst.

8. A continuous separation and concentration method using the alkyl oxalate catalyst continuous separation and concentration device according to any one of claims 1 to 7, characterized in that: The following steps are involved: The mixed liquid of alkyl oxalate and catalyst is passed into the cyclone separation assembly in the shell for cyclone separation. The upper layer of liquid enters the liquid phase space from the top, and the lower layer of catalyst enters the sedimentation space from the bottom, thus completing the preliminary separation in the shell. Under the action of the air pressure in the gas phase space, the dead-end filter assembly filters the liquid in the liquid phase space, and the filtered clear liquid is discharged from the shell from the liquid outlet of the dead-end filter assembly to complete the secondary filtration in the shell; The feed rate of the cyclone separation component is equal to the sum of the discharge rate of the filtered clear liquid and the discharge rate of the catalyst, so that the liquid level in the liquid phase space remains stable and a continuous separation and concentration process is achieved.

9. A continuous separation and concentration method according to claim 8, characterized in that: There are several groups of dead-end filter components. After running for a preset time, one group of dead-end filter components is backflushed. After the backflushing of this group of dead-end filter components is completed, it is put into use again after an interval of 5-10 minutes to allow the backflushed catalyst filter cake to fully settle to the bottom of the shell.

10. A continuous separation and concentration method according to claim 8, characterized in that: The concentration ratio can be adjusted by adjusting the discharge rate of the catalyst and adjusting the feed rate.

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