CN114602319A

CN114602319A - Membrane separation and purification method

Info

Publication number: CN114602319A
Application number: CN202210368852.0A
Authority: CN
Inventors: 不公告发明人
Original assignee: Zhejiang Huiyong New Material Co ltd
Current assignee: Zhejiang Huiyong New Material Co ltd
Priority date: 2022-04-08
Filing date: 2022-04-08
Publication date: 2022-06-10
Anticipated expiration: 2042-04-08
Also published as: CN114602319B

Abstract

The invention provides a membrane separation and purification method, which utilizes membrane separation and purification equipment comprising a heat supply module, an N-level membrane separation module, N first transmission pipelines and at least N-1 second transmission pipelines; n is a positive integer not less than 2; each stage of membrane separation module is used for carrying out membrane separation and purification treatment on one material to obtain a corresponding product; the heat supply module supplies heat to the first-stage membrane separation module; a first transmission pipeline for introducing a product generated by the previous-stage membrane separation module into the next-stage membrane separation module to perform first heat exchange and a second transmission pipeline for outputting the product subjected to the first heat exchange into the previous-stage membrane separation module to perform second heat exchange are connected between the two adjacent stages of membrane separation modules; and the Nth-stage membrane separation module leads the product generated by the Nth-stage membrane separation module into the Nth-stage membrane separation module through a first transmission pipeline so as to carry out third heat exchange with the material led into the Nth-stage membrane separation module. The method can effectively improve the heat utilization rate.

Description

Membrane separation and purification method

Technical Field

The invention belongs to the technical field of organic azeotrope purification, and particularly relates to a membrane separation and purification method.

Background

In the chemical field, organic raw materials such as alcohols, ketones, aldehydes, ethers, lipids and the like are often required to be separated and purified, and impurities such as water and the like in the chemical raw materials are removed through separation and purification, so that a product with higher purity is obtained. However, since these organic materials and water are azeotropic systems, it is difficult to separate them by a common separation method and to obtain a product having a high purity. For the separation, an azeotropic distillation method, an extractive distillation method, an adsorption separation method, or the like is generally used. However, the prior methods have the problems of low heat utilization rate, high energy consumption, substandard direct wastewater discharge and the like.

Disclosure of Invention

The embodiment of the invention provides membrane separation and purification equipment, which aims to solve the problems of low heat utilization rate, high energy consumption and the like in the existing azeotropic system chemical raw material separation and purification process.

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

a membrane separation and purification method adopts membrane separation and purification equipment to carry out membrane separation and purification;

the membrane separation and purification equipment comprises a heat supply module, an N-level membrane separation module, N first transmission pipelines and at least N-1 second transmission pipelines; wherein N is a positive integer not less than 2;

each stage of the membrane separation module is used for carrying out membrane separation and purification treatment on one material to obtain a corresponding product;

the first stage of the membrane separation module is supplied with heat by the heat supply module to carry out membrane separation and purification treatment;

the adjacent two stages of membrane separation modules are respectively communicated through one first transmission pipeline and one second transmission pipeline; the first transmission pipeline is used for introducing a product generated by the membrane separation module of the previous stage into the membrane separation module of the next stage so as to perform first heat exchange with a material introduced into the membrane separation module of the next stage; the second transmission pipeline is used for outputting the product subjected to the first heat exchange to the membrane separation module at the upper stage so as to perform second heat exchange with the material introduced into the membrane separation module at the upper stage;

the Nth-stage membrane separation module leads a product generated by the Nth-stage membrane separation module into the Nth-stage membrane separation module through one first transmission pipeline so as to carry out third heat exchange with a material led into the Nth-stage membrane separation module;

the membrane separation and purification method comprises the following steps:

introducing a material into each stage of membrane separation module, and supplying heat to the first stage of membrane separation module by the heat supply module to perform membrane separation and purification treatment;

controlling the flow of the material entering the membrane separation module of the previous stage in the two adjacent stages of membrane separation modules to be larger than the flow of the material entering the membrane separation module of the next stage;

each of the materials contained an organic azeotrope.

In some embodiments, the latent heat value of the material entering the membrane separation module of the previous stage in two adjacent stages of the membrane separation modules is controlled to be not less than the latent heat value of the material entering the membrane separation module of the next stage.

In some embodiments, each stage of the membrane separation module comprises a first heat exchanger, a third transfer line, a first evaporator, a fourth transfer line and at least one membrane module which are communicated in sequence;

the heat supply module supplies heat to the first evaporator in the membrane separation module of the first stage;

in the two adjacent stages of membrane separation modules, the feed end of the first transmission pipeline is communicated with the membrane module in the previous stage of membrane separation module, the discharge end of the first transmission pipeline is communicated with the first evaporator in the next stage of membrane separation module, the feed end of the second transmission pipeline is communicated with the first evaporator in the next stage of membrane separation module, and the discharge end of the second transmission pipeline is communicated with the first heat exchanger in the current stage of membrane separation module.

In some embodiments, each stage of the membrane separation module further comprises a fifth transfer line, each stage of the membrane separation module comprising a first membrane module and a second membrane module;

the fourth transfer line is communicated between the first evaporator and the first membrane module, and the fifth transfer line is communicated between the first membrane module and the second membrane module; one end of the first transmission pipeline communicated with the membrane separation modules of two adjacent stages is communicated with the second membrane module.

In some embodiments, each stage of the membrane separation modules further comprises a permeate condensing assembly in communication with the membrane modules for subjecting permeate vapor produced by the membrane modules to a permeate condensing process;

or each stage of the membrane separation module further comprises a permeate condensation component, a first membrane component and a second membrane component, and the permeate condensation component in each stage of the membrane separation module comprises two permeate condensers and two cooling water pipelines; the membrane separation equipment also comprises a vacuum module and a cold water module;

the first membrane module is in communication with one of the permeate condensers; one cooling water pipeline is used for introducing a water source with the temperature of 5-15 ℃ into the penetration condenser communicated with the first membrane component; the second membrane module is communicated with the other osmotic condenser; the other cooling water pipeline leads a water source with the temperature of minus 15 to minus 5 ℃ into the osmotic condenser which is communicated with the second membrane component; and when the membrane separation and purification are carried out, controlling the vacuum degree of the penetration condenser with the water source of 5-15 ℃ introduced into each stage of the membrane separation module to be higher than the vacuum degree of the penetration condenser with the water source of-15-5 ℃.

In some embodiments, N has a value of 2 or 3 or 4;

and/or, the membrane separation and purification equipment also comprises a storage module which is used for recovering penetrating fluid produced by each stage of the membrane separation module.

In some embodiments, the membrane separation and purification equipment further comprises a cooling module, wherein the cooling module is used for cooling the product subjected to the third heat exchange by the membrane separation module of the Nth stage;

or, the membrane separation and purification equipment further comprises a cooling module and a circulating water module, wherein the cooling module is used for cooling a product subjected to the third heat exchange by the Nth-stage membrane separation module; the circulating water module is communicated with the cooling module.

In some embodiments, the first transfer line connected to the membrane separation module of the nth stage comprises a first branch and a second branch;

the membrane separation and purification equipment also comprises a functional heat exchange module;

the first branch is communicated with the Nth-stage membrane separation module and the functional heat exchange module so as to introduce a product generated by the Nth-stage membrane separation module into the functional heat exchange module and carry out fourth heat exchange;

the second branch is communicated with the functional heat exchange module and the Nth-stage membrane separation module so as to lead the product subjected to the fourth heat exchange to the Nth-stage membrane separation module for the third heat exchange.

In some embodiments, the functional heat exchange module comprises any one of a rectification module, a molecular sieve adsorption module.

In some embodiments, the rectification module comprises a second heat exchanger, a rectification column, a boiler, a third condenser, a seventh transfer line, an eighth transfer line, a ninth transfer line, a tenth transfer line, and an eleventh transfer line;

the discharge end of the first branch is communicated with the boiler; the feed end of the second branch is communicated with the boiler;

the seventh transmission pipeline is communicated between the second heat exchanger and the rectifying tower so as to lead the material passing through the second heat exchanger to the rectifying tower;

the eighth transmission pipeline is communicated between the rectifying tower and the boiler so as to introduce the tower bottom liquid generated by the rectifying tower into the boiler;

the ninth transmission pipeline is communicated between the boiler and the rectifying tower so as to transmit the tower bottom liquid heated by the boiler into the rectifying tower;

the tenth transmission pipeline is communicated between the boiler and the second heat exchanger so as to convey the tower bottom liquid heated by the boiler into the second heat exchanger and provide a heat source for the second heat exchanger;

and the eleventh transmission pipeline is communicated between the rectifying tower and the third condenser so as to convey the gaseous azeotropic material discharged from the top of the rectifying tower into the third condenser for condensation treatment.

In some embodiments, the membrane separation purification apparatus further comprises a circulating water module in communication with the third condenser;

and/or the membrane separation and purification equipment further comprises a recovery device, and the recovery device is communicated with the third condenser and is used for collecting the azeotrope discharged by the third condenser;

and/or the membrane separation modules of each stage are also communicated with the second heat exchanger so as to lead penetrating fluid generated by the membrane separation modules of each stage to the second heat exchanger.

In some embodiments, the molecular sieve adsorption module comprises a third heat exchanger, a twelfth transfer line, a second evaporator, a thirteenth transfer line, and at least one adsorption column assembly in sequential communication;

the discharge end of the first branch is communicated with the second evaporator; the feed end of the second branch is communicated with the second evaporator.

In some embodiments, the molecular sieve adsorption module further comprises a fourteenth transfer line, the fourteenth transfer line communicating the adsorption column assembly and the third heat exchanger to pass vapor generated by the adsorption column assembly to the third heat exchanger and to perform a sixth heat exchange with the material passed to the third heat exchanger.

In some embodiments, each stage of the membrane separation modules produces a permeate, and the rectification modules are fed with either the permeate produced by any of the membrane separation modules or with either of the materials; and (3) introducing penetrating fluid generated by any membrane separation module or introducing any material into the molecular sieve adsorption module.

In some embodiments, the organic azeotrope is selected from any one of alcohols, ketones, aldehydes, ethers, and esters.

Compared with the prior art, the membrane separation and purification method provided by the invention is based on membrane separation and purification equipment, wherein the membrane separation and purification equipment comprises a heat supply module and N-stage membrane separation modules, the first-stage membrane separation module supplies heat to perform membrane separation and purification treatment through the heat supply module, products generated by the previous-stage membrane separation module are conveyed to the next-stage membrane separation module through a first conveying pipeline between the two adjacent stages of membrane separation modules, first heat exchange is performed in the next-stage membrane separation module to realize heat supply to the next-stage membrane separation module, products subjected to heat exchange in the next-stage membrane separation module through a second conveying pipeline are conveyed back to the previous-stage membrane separation module to perform second heat exchange, the membrane separation and purification method based on the membrane separation and purification equipment realizes thermal coupling supply of the membrane separation modules at all stages and thermal coupling in the membrane separation process, thereby effectively improving the heat utilization rate of membrane separation and purification and reducing energy consumption.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a simplified structural schematic diagram of a membrane separation and purification apparatus provided in an embodiment of the present invention;

FIG. 2 is a simplified structural schematic diagram of a membrane separation module provided in an embodiment of the present invention;

FIG. 3 is a simplified block diagram of a cooling module provided by an embodiment of the present invention;

FIG. 4 is a simplified structural diagram of a membrane separation and purification apparatus provided in another embodiment of the present invention;

FIG. 5 is a simplified schematic diagram of a rectification module provided by an embodiment of the invention;

fig. 6 is a simplified structural schematic diagram of a molecular sieve adsorption module provided by an embodiment of the present invention.

Reference numbers of the drawings:

10. membrane separation and purification equipment;

11. a heat supply module;

12. a membrane separation module; 121. a first stage membrane separation module; 122. a second stage membrane separation module; 123. a third stage membrane separation module; 1201. a first heat exchanger; 1202. a third transfer line; 1203. a first evaporator; 1204. a fourth transfer line; 1205. a membrane module; 12051. a first membrane module; 12052. a second membrane module; 1206. a fifth transfer line; 1207. a pervaporation condensation assembly; 12071. a sixth transfer line; 12072. a penetration condenser; 12073. a cooling water line; 12074. a vacuum line;

13. a first transfer line; 131. a first branch; 132. a second branch circuit;

14. a second transfer line;

15. a vacuum module;

16. a cold water module;

17. a storage module;

18. a cooling module; 181. a first condenser; 182. a second condenser;

19. a circulating water module;

20. a functional heat exchange module;

21. a rectification module; 211. a second heat exchanger; 212. a rectifying tower; 213. a boiler; 214. a third condenser; 215. a seventh transfer line; 216. an eighth transfer line; 217. a ninth transfer line; 218. a tenth transfer line; 219. an eleventh transfer line;

22. a molecular sieve adsorption module; 221. a third heat exchanger; 222. a twelfth transfer line; 223. a second evaporator; 224. a thirteenth transfer line; 225. an adsorption column assembly; 226. a fourteenth transfer line.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects solved by the present invention more clearly apparent, the present invention 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 merely illustrative of the invention and are not intended to limit the invention.

Noun definition explanation:

in the present invention, the two concepts of the previous stage membrane separation module and the next stage membrane separation module are referred to, and the previous stage membrane separation module and the next stage membrane separation module do not mean that there is a membership relationship between the two membrane separation modules, but mean that in the adjacent two membrane separation modules, the membrane separation module that supplies heat is defined as the previous stage, and the membrane separation module that receives heat is defined as the next stage.

The technical solution of the present invention is explained in detail below.

Referring to fig. 1 to 3, a membrane separation and purification apparatus 10 according to an embodiment of the present invention includes a heat supply module 11, an N-stage membrane separation module 12, N first transmission pipelines 13, and at least N-1 second transmission pipelines 14; wherein N is a positive integer not less than 2.

Specifically, each stage of membrane separation module 12 is used for performing membrane separation and purification treatment on a material to obtain a corresponding product, and simultaneously generating a corresponding penetrating fluid; the first-stage membrane separation module 121 is supplied with heat by the heat supply module 11 to perform membrane separation and purification treatment; the adjacent two stages of membrane separation modules 12 are respectively communicated through a first transmission pipeline 13 and a second transmission pipeline 14; the first transmission pipeline 13 is used for introducing a product generated by the previous-stage membrane separation module 12 into the next-stage membrane separation module 12 to perform first heat exchange with a material introduced into the next-stage membrane separation module 12, so as to supply heat to the next-stage membrane separation module 12; and the second transmission pipeline 14 is used for outputting the product after the first heat exchange to the upper-stage membrane separation module 12 so as to perform second heat exchange with the material introduced into the upper-stage membrane separation module 12, so that the product produced by the upper-stage membrane separation module 12 is subjected to twice heat exchange, and the temperature of the product produced by the upper-stage membrane separation module 12 reaches the temperature suitable for collection. The nth membrane separation module 12 passes the product produced by the nth membrane separation module 12 through a first transmission pipeline 13 to the nth membrane separation module 12 for third heat exchange with the material passed to the nth membrane separation module 12.

When the membrane separation and purification treatment is performed by the membrane separation and purification device 10, at least the following steps are included: a material is introduced into each stage of membrane separation module 12, the heat supply module 11 supplies heat to the first stage of membrane separation membrane module 121 to carry out membrane separation and purification treatment, the flow of the material entering the previous stage of membrane separation module 12 in the adjacent two stages of membrane separation modules 12 is controlled to be larger than the flow of the material entering the next stage of membrane separation module 12, and each introduced material contains organic azeotrope.

Because the membrane separation and purification device 10 of the present embodiment realizes the cascade connection and the heat coupling of the plurality of membrane separation modules 12 by the heat transfer supply among the plurality of membrane separation modules 12, the heat carried by the product generated by each membrane separation module 12 is fully utilized, the heat utilization rate of the membrane separation and purification device 10 is effectively improved, and the energy consumption of the membrane separation and purification device 10 is reduced. Therefore, the membrane separation and purification method based on the membrane separation and purification equipment 10 only needs the heat supply module 11 to supply heat to the first-stage membrane separation module 121, and can supply heat for membrane separation treatment of other membrane separation modules 12 through heat coupling, so that the effective utilization rate of heat in membrane separation and purification can be effectively improved, and the energy consumption is reduced.

For the embodiment, as long as the latent heat value of the material introduced into the previous membrane separation module 12 is greater than the latent heat value of the material introduced into the next membrane separation module 12 and the heat supply module 11 is controlled to supply heat to the first membrane separation module 121, the normal operation of the membrane separation and purification equipment 10 in the membrane separation and purification process can be ensured, and the utilization rate of heat can be effectively improved and energy can be saved. In some embodiments, the materials suitable for being introduced into each membrane separation module 12 of the membrane separation and purification apparatus 10 of this embodiment for membrane separation and purification may be the same materials or different materials. In some embodiments, the feed may contain organic azeotropes which may be alcohols, ketones, aldehydes, lipids, and the like. In some embodiments, the introduced material may be hydrous ethanol, and if the flow rate of the hydrous ethanol material introduced into the previous membrane separation module 12 is greater than the flow rate of the hydrous ethanol material introduced into the next membrane separation module 12, the effective utilization of heat in the membrane separation and purification can be realized. In some embodiments, the introduced materials are all ethanol raw materials containing water, and the water content of the materials introduced into each stage of the membrane separation module 12 is a value in x, wherein x is more than 0 and less than or equal to 35%, and the unit of the water content may be volume content, mass content or weight content, which is determined according to the material properties.

In some embodiments, the heat supply module 11 supplies steam, and the heat supply module 11 supplies steam to the first evaporator 1203 of the first stage membrane separation module 121, so that good heat exchange can be performed with the material supplied to the first stage membrane separation module 121, and the vaporization efficiency of the material is improved. By adopting the heat supply design, the heat can be transmitted and exchanged to the whole membrane separation and purification equipment 10 only by supplying heat to the first-stage membrane separation module 121 by the heat supply module 11, so that heat can be supplied to the whole membrane separation and purification equipment 10.

In some embodiments, the value of N is 2, that is, the membrane separation and purification apparatus 10 includes a first-stage membrane separation module 121 and a second-stage membrane separation module 122, the first-stage membrane separation module 121 supplies heat through a heat supply module 11 to realize vaporization of the material introduced into the first-stage membrane separation module 121, so that the material introduced into the first-stage membrane separation module 121 is subjected to membrane separation and purification treatment in the first-stage membrane separation module 121, and a product obtained by the membrane separation and purification treatment performed by the first-stage membrane separation module 121 is introduced into the second-stage membrane separation module 122 through a first transmission pipeline 13 to provide heat (first heat exchange) for the second-stage membrane separation module 122, so that the material introduced into the second-stage membrane separation module 122 is heated and vaporized, so that the material introduced into the second-stage membrane separation module 122 is subjected to membrane separation and purification treatment in the second-stage membrane separation module 122, and after providing heat for the second-stage membrane separation module 122, the product of the first-stage membrane separation module 121 is conveyed into the first-stage membrane separation module 121 through a second conveying pipeline 14 to perform second heat exchange on the material introduced into the first-stage membrane separation module 121, so that the temperature of the product obtained by the first-stage membrane separation module 121 is reduced to a temperature suitable for collection, the temperature of the material entering the first-stage membrane separation module 121 is increased after the second heat exchange, and heat is supplied through the heat supply module 11, so that vaporization can be realized. Of course, the value of N is not limited to 2, and may be other integers such as 3, 4, or 5.

Referring to fig. 1 and 2, in some embodiments, each stage of membrane separation module 12 includes a first heat exchanger 1201, a third transfer line 1202, a first evaporator 1203, a fourth transfer line 1204, and at least one membrane module 1205, and the first heat exchanger 1201, the third transfer line 1202, the first evaporator 1203, the fourth transfer line 1204, and the membrane module 1205 are in serial communication. Wherein, the heat supply module 11 supplies heat to the first evaporator 1203 in the first-stage membrane separation module 121; in the two adjacent stages of membrane separation modules 12, the feed end of the first transmission pipeline 13 is communicated with the membrane module 1205 in the previous stage of membrane separation module 12, the discharge end is communicated with the first evaporator 1203 in the next stage of membrane separation module 12, the feed end of the second transmission pipeline 14 is communicated with the first evaporator 1203 in the next stage of membrane separation module 12, and the discharge end is communicated with the first heat exchanger 1201 of the previous stage of membrane separation module 12. In such a connection relationship, the product generated by the previous membrane separation module 12 is subjected to first heat exchange with the material introduced into the next membrane separation module 12, and then returns to the current membrane separation module 12, and is subjected to second heat exchange with the material introduced into the current membrane separation module 12, so that the temperature of the product generated by the current membrane separation module 12 reaches the temperature suitable for collection, and the next membrane separation module 12 obtains heat, thereby performing membrane separation and purification treatment. In this embodiment, the membrane module 1205 is a molecular sieve membrane, and the molecular sieve membrane is used as the membrane module 1205, so that not only is the occupied space for equipment installation small, but also the separation and purification process is a static process, and a tower does not need to be switched, and the recovery rate is high. If the separated and purified material is hydrous ethanol, the recovery rate of the ethanol reaches more than 99.9 percent after passing through the membrane module 1205.

In some embodiments, each stage of membrane separation modules 12 further includes a fifth transfer line 1206, and each stage of membrane separation modules 12 includes a first membrane module 12051 and a second membrane module 12052. The fourth transmission pipeline 1204 is communicated between the first evaporator 1203 and the first membrane module 12051, so that the material vaporized by the first evaporator 1203 is conveyed to the first membrane module 12051 for membrane separation and purification treatment, and a primary product and a first penetrating fluid steam are obtained after the membrane separation and purification treatment of the first membrane module 12051; the fifth transmission pipeline 1206 is communicated between the first membrane module 12051 and the second membrane module 12052, so that the primary product obtained by the separation and purification treatment of the first membrane module 12051 is transmitted to the second membrane module 12052 for the membrane separation and purification treatment again, thereby obtaining a product and a second penetrating fluid steam; the feed end of the first transfer line 13 in the adjacent two-stage membrane separation module 12 is communicated with the second membrane module 12052 of the previous-stage membrane separation module 12, so that the product obtained from the previous-stage membrane separation module 12 is conveyed to the next-stage membrane separation module 12. By providing the first membrane module 12051 and the second membrane module 12052, the effect of membrane separation and purification can be further improved, which is beneficial to obtaining a product with higher purity, and further improves the utilization rate of heat.

In some embodiments, each stage of membrane separation modules 12 further includes a permeate condensing assembly 1207, the permeate condensing assembly 1207 being in communication with the membrane modules 1205 for performing a permeate condensing process on permeate vapor produced by the membrane modules 1205. By providing a permeate condensing module 1207, permeate vapor collection is facilitated, and the direct discharge of permeate vapor to the environment, which can adversely affect the environment, is avoided.

In some embodiments, the membrane separation and purification apparatus 10 further comprises a vacuum module 15 and a cold water module 16, and the permeate condensing module 1207 comprises a sixth transport line 12071, a permeate condenser 12072, a cooling water line 12073, and a vacuum line 12074. Wherein a sixth transfer line 12071 is connected between the membrane module 1205 and the permeate condenser 12072 such that permeate vapor produced by the membrane module 1205 is passed to the permeate condenser 12072; the cooling water pipeline 12073 is communicated with the cold water module 16 and the osmotic condenser 12072, so that a water source with the temperature below 15 ℃ can be introduced into the osmotic condenser 12072, and the low-temperature water is utilized to carry out condensation treatment on penetrating fluid steam; the vacuum line 12074 is connected between the osmotic condenser 12072 and the vacuum module 15 to create a vacuum condition for the osmotic condenser 12072, and the effect of osmotic condensation can be effectively improved by creating the vacuum condition.

Since in some embodiments, a first permeate vapor is also produced when the membrane separation process is performed in the first membrane modules 12051, a second permeate vapor is produced when the membrane separation process is performed in the second membrane modules 12052, and the first permeate vapor and the second permeate vapor have different compositions and temperatures, the permeate condensing modules 1207 in each stage of the membrane separation modules 12 include two permeate condensers 12072 and two cooling water lines 12073. The first membrane module 12051 is communicated with one of the permeable condensers 12072, and one cooling water pipeline 12073 is used for introducing a water source with the temperature of 5-15 ℃ into the permeable condenser 12072 communicated with the first membrane module 12051 to assist condensation. The second membrane module 12052 is communicated with another osmotic condenser 12072, and the other cooling water pipeline 12073 is used for introducing a water source with the temperature of minus 15 to minus 5 ℃ into the osmotic condenser 12072 communicated with the second membrane module 12052 to assist condensation. The permeate condensing module 1207 is designed to facilitate condensing permeate vapors in different states. In some embodiments, the vacuum line 12074 of each stage of membrane separation module 12 also includes two lines, one of the two lines is communicated with the permeate condenser 12072 communicated with the first membrane module 12051, and the other line is communicated with the permeate condenser 12072 communicated with the second membrane module 12052, so as to adjust the vacuum condition of each permeate condenser 12072, and the vacuum condition of each permeate condenser 12072 is that, during the membrane separation and purification treatment, the vacuum degree of the permeate condenser 12072, into which the water source of 5 to 15 ℃ is introduced, in each stage of membrane separation module 12 is controlled to be higher than the vacuum degree of the permeate condenser 12072, into which the water source of-15 to-5 ℃ is introduced, so as to facilitate improving the effect of permeate condensation, and the specific vacuum degree can be adjusted according to the purity of membrane separation and purification, and detailed descriptions are not expanded herein.

Referring to fig. 1 and 2, in some embodiments, the membrane separation and purification apparatus 10 further includes a storage module 17, and by arranging the storage module 17, the permeate produced by the membrane separation modules 12 at each stage can be effectively recovered. In some embodiments, permeate vapor produced by the first membrane module 12051 is condensed by the permeate condensing module 1207 and is discharged directly to the storage module 17, and similarly, permeate vapor produced by the second membrane module 12052 is condensed by the permeate condensing module 1207 and is discharged directly to the storage module 17. In some embodiments, the storage module 17 is a liquid reservoir.

Referring to fig. 1, 2 and 3, in some embodiments, the membrane separation and purification apparatus 10 further includes a cooling module 18, and the cooling module 18 is configured to cool the product subjected to the third heat exchange by the nth-stage membrane separation module 12, so that the temperature of the product generated by the nth-stage membrane separation module 12 can reach a temperature suitable for collection.

In some embodiments, the cooling module 18 includes a first condenser 181 and a second condenser 182. Wherein, the first condenser 181 is used for performing a first cooling treatment on the third heat-exchanged product; and the second condenser 182 is used to perform a second cooling process on the first cooled product. Through two-step cooling, the product which is in a gas-liquid mixed state after the third heat exchange treatment can be changed into a high-temperature liquid product, and then the high-temperature liquid product is changed into a liquid product with a temperature suitable for collection.

Referring to fig. 1 and 3, in some embodiments, the membrane separation and purification apparatus 10 further includes a circulating water module 19, and the circulating water module 19 is communicated with the cooling module 18, so as to cool the product in a gas-liquid mixed state after the third heat exchange treatment. In some embodiments, the circulating water module 19 is in communication with the first condenser 181 and the second condenser 182, respectively, to achieve separate cooling.

In the above embodiment, the membrane separation and purification apparatus 10 including the multistage membrane separation module 12 can realize the coupling utilization of heat only by supplying a heat source to the first-stage membrane separation module 121, and has the characteristics of simple operation, high quality of the produced product, low energy consumption, small occupied area, easy capacity expansion and the like, compared with the conventional azeotropic distillation. Compared with molecular sieve adsorption, the method has the characteristics of continuous operation, no need of frequent switching for heating regeneration, low energy consumption, smaller occupied area, easy capacity expansion and the like.

Referring to fig. 4, in some embodiments, the membrane separation and purification apparatus 10 further includes a functional heat exchange module 20, and the functional heat exchange module 20 performs heat exchange by using the product generated by the nth-stage membrane separation module 12 to supply heat to the functional heat exchange module 20, so as to further improve effective utilization of heat carried in the product generated by the nth-stage membrane separation module 12 in the nth-stage membrane separation module 12.

In some embodiments, the first transfer line 13 connected to the nth stage membrane separation module 12 includes a first branch 131 and a second branch 132. The first branch 131 is communicated with the nth-stage membrane separation module 12 and the functional heat exchange module 20, so that a product generated by the nth-stage membrane separation module 12 can be introduced into the functional heat exchange module 20 and fourth heat exchange is performed in the functional heat exchange module 20; the second branch 132 communicates the functional heat exchange module 20 and the nth-stage membrane separation module 12 to pass the fourth heat-exchanged product to the nth-stage membrane separation module 12 for the third heat exchange with the material passed to the nth-stage membrane separation module 12. Due to the structural design, not only can the effective utilization of heat carried by products generated by the membrane separation module 12 be improved, but also the structure of the membrane separation and purification equipment 10 can be more compact, and the utilization rate of the installation space of the membrane separation and purification equipment 10 can be effectively improved. In some embodiments, the functional heat exchange module 20 may be a rectification module 21 or a molecular sieve adsorption module 22, so that the heat generated by the membrane separation module 12 can be fully utilized for rectification or molecular adsorption treatment.

Referring to fig. 4, 5 and 6, when the functional heat exchange module 20 is the rectification module 21, the rectification module 21 includes a second heat exchanger 211, a rectification tower 212, a boiler 213, a third condenser 214, a seventh transfer line 215, an eighth transfer line 216, a ninth transfer line 217, a tenth transfer line 218 and an eleventh transfer line 219. The seventh transmission pipeline 215 is communicated between the second heat exchanger 211 and the rectifying tower 212, so that the material passing through the second heat exchanger 211 is introduced into the rectifying tower 212; the eighth transmission pipeline 216 is communicated between the rectifying tower 212 and the boiler 213, so as to introduce the tower bottom liquid generated by the rectifying tower 212 into the boiler 213 for heating treatment, i.e. to perform fourth heat exchange with the product conveyed by the nth-stage membrane separation module 12; the ninth transmission pipeline 217 is communicated with the boiler 213 and the rectifying tower 212, and is used for refluxing and transmitting the tower bottom liquid heated by the boiler 213 to the rectifying tower 212, supplementing the liquid of the rectifying tower 212 and performing secondary rectification; the tenth transmission pipeline 218 is communicated between the boiler 213 and the second heat exchanger 211, so as to convey the tower bottom liquid heated by the boiler 213 into the second heat exchanger 211 and provide a heat source for the second heat exchanger 211, so that the tower bottom liquid is subjected to fifth heat exchange with the material introduced into the rectification module 21 through the second heat exchanger 211, and the tower bottom liquid subjected to the fifth heat exchange can be directly discharged; the eleventh transfer line 219 is connected between the rectifying tower 212 and the third condenser 214, so as to convey the gaseous azeotropic material discharged from the top of the rectifying tower 212 to the third condenser 214 for condensation, and the gaseous azeotropic material condensed by the third condenser 214 can obtain an azeotrope. In some embodiments, membrane separation purification apparatus 10 further comprises a recovery unit (not shown) for recovering the azeotrope discharged from third condenser 214. In some embodiments, the feed to the rectification module 21 may be any permeate produced by the N stages of membrane separation modules 12, and the rectification treatment of the permeate may be effectively improved by feeding any permeate produced by the N stages of membrane separation modules 12 to the rectification module 21, so that the permeate can be directly discharged after the rectification treatment, and the discharge reaches the direct discharge standard (GB 8978-1996). Of course, other materials that can be rectified, such as the same material as the membrane separation module 12 or different materials from the membrane separation module 12, may be introduced into the rectification module 21. In some embodiments, the circulating water module 19 is also in communication with the third condenser 214 to assist in cooling the gaseous azeotrope produced by the rectification column 212, so that the gaseous azeotrope can be effectively cooled so that it becomes a liquid azeotrope for collection.

In the embodiment, the membrane separation module 12 is combined with rectification, so that the heat coupling with the rectification is realized on the basis of realizing the heat coupling of the multistage membrane separation module 12, a molecular sieve membrane can be used in combination with the rectification, and the heat utilization rate is improved and the energy consumption is saved. When the hydrous ethanol is used as a raw material for separation and purification, the water content in the ethanol steam at the top of the rectifying tower 212 can reach a higher value, and the azeotropic distillation process is not required, so that the energy consumption of the rectifying tower 212 is reduced, the rectifying condition of the rectifying tower 212 is reduced, and the once-through recovery rate of the membrane separation module 12 reaches more than 99.5 percent, so that the energy consumption of the whole set of equipment in the hydrous ethanol separation and purification is further reduced. In this embodiment, the membrane separation and purification device 10 employs a combination of the membrane separation module 12 and the rectification module 20, and when ethanol is dehydrated and purified, compared with a combination of molecular sieve adsorption and rectification, for separating and purifying 1 ton of hydrous ethanol material, the heat supply module 11 can introduce less steam than 180kg, the consumption of circulating water can be saved by more than 10 tons, and the electric quantity can be saved by more than 5 degrees, so that not only is the energy consumption saved, but also the cost of separation and purification can be reduced.

Referring to fig. 4 and 6, when the functional heat exchange module 20 is a molecular sieve adsorption module 22, the molecular sieve adsorption module 22 includes a third heat exchanger 221, a twelfth transfer pipeline 222, a second evaporator 223, a thirteenth transfer pipeline 224 and at least one adsorption tower assembly 225, and the third heat exchanger 221, the twelfth transfer pipeline 222, the second evaporator 223, the thirteenth transfer pipeline 224 and the adsorption tower assembly 225 are sequentially communicated, while a feed end of the first branch 131 is communicated with the membrane assembly 1205 of the nth stage membrane separation module 12, and a discharge end of the first branch 131 is communicated with the second evaporator 223; the feed end of the second branch 132 is communicated with the second evaporator 223, and the discharge end of the second branch 132 is communicated with the first heat exchanger 1201 in the nth stage membrane separation module 12. In some embodiments, the molecular sieve adsorption module 22 further comprises a fourteenth transfer line 226, and the fourteenth transfer line 226 is connected between the adsorption tower unit 225 and the third heat exchanger 221, so that the steam generated by the adsorption tower unit 225 can be passed to the third heat exchanger 221 and undergo a sixth heat exchange with the material passed into the third heat exchanger 221. The feed to the molecular sieve adsorption module 22 may be the same feed as the membrane separation module 12, or a different feed from the membrane separation module 12, or, of course, may be any permeate produced by the N-stage membrane separation modules 12. Due to the structural design, the heat utilization rate of the molecular sieve adsorption module 22 can be further improved, and the supply of external heat is reduced so as to reduce energy consumption.

Referring to fig. 1 to fig. 3, the basic operation principle of the membrane separation and purification apparatus 10 of the present embodiment is illustrated as follows by using a structure including three stages of membrane separation modules 12:

(1) the basic working process of the first-stage membrane separation module 121 is as follows: introducing a first material into the first-stage membrane separation module 121, wherein the first material has no heat exchange process when passing through the first heat exchanger 1201, the first material is conveyed to the first evaporator 1203, meanwhile, the heat supply module 11 introduces steam into the first evaporator 1203, the first material undergoes first heat exchange with the steam when passing through the first evaporator 1203, the first material is vaporized into a gaseous material, and is conveyed to the first membrane module 12051 for first membrane separation treatment, the gaseous first material subjected to the first membrane separation treatment is separated into a first primary product and first permeate steam, the first primary product is conveyed to the second membrane module 12052 for second membrane separation treatment, meanwhile, the first permeate steam is conveyed to a permeate condenser 12072 communicated with the first membrane module 12051 for first permeate condensation treatment and produces corresponding permeate, when the first permeate steam is subjected to first permeate condensation, the cold water module 16 feeds water with the temperature of 5-15 ℃ into the osmotic condenser 12072 communicated with the first membrane module 12051, and the vacuum module 15 works to enable the osmotic condenser 12072 communicated with the first membrane module 12051 to form a certain vacuum degree so as to assist in osmotic condensation; the first primary product subjected to the second membrane separation treatment is divided into a first product and second penetrating fluid steam, wherein the second penetrating fluid steam is conveyed to a penetration condenser 12072 communicated with the second membrane module 12052 for second penetration condensation treatment and produces corresponding penetrating fluid, and when the second penetrating fluid steam is subjected to second penetration condensation, the cold water module 16 introduces water at-15 ℃ to-5 ℃ into the penetration condenser 12072 communicated with the second membrane module 12052 and forms a certain vacuum degree, and the vacuum degree is lower than that of the penetration condenser 12072 introduced with a water source at 5 ℃ to 15 ℃ so as to assist penetration condensation; and the first product enters the first evaporator 1203 of the second stage membrane separation module 122 via the first transfer line 13, and heat exchange is performed in the first evaporator 1203 of the second stage membrane separation module 122.

(2) Basic working process of the second stage membrane separation module 122: feeding a second material into the second-stage membrane separation module 122, wherein when a first batch of the second material passes through the first heat exchanger 1201, no heat exchange is performed, the second material is conveyed to the first evaporator 1203, first heat exchange is performed between the second material and a first product conveyed to the first evaporator 1203 by a first conveying pipeline 13 connected with the first-stage membrane separation module 121 and the second-stage membrane separation module 122, the second material is changed into a gaseous state and conveyed to the first membrane module 12051 for first membrane separation treatment, the gaseous second material subjected to the first membrane separation treatment is separated into a second primary product and a third penetrating fluid steam, the second primary product is conveyed to the second membrane module 12052 for second membrane separation treatment, the third penetrating fluid steam is conveyed to a penetration condenser 12072 communicated with the first membrane module 12051 for second penetration condensation treatment and corresponding penetrating fluid is produced, and when the third penetrating fluid steam is subjected to first penetration condensation, the cold water module 16 feeds water with the temperature of 5-15 ℃ into the osmotic condenser 12072 communicated with the first membrane module 12051, and the vacuum module 15 works to enable the osmotic condenser 12072 communicated with the first membrane module 12051 to form a certain vacuum degree so as to assist in osmotic condensation; the second primary product subjected to the second membrane separation treatment is divided into a second product and a fourth penetrating fluid steam, wherein the fourth penetrating fluid steam is conveyed to a penetrating condenser 12072 communicated with the second membrane module 12052 for second penetrating condensation treatment and produces corresponding penetrating fluid, and when the fourth penetrating fluid steam is subjected to second penetrating condensation, the cold water module 16 introduces water at-15 ℃ to-5 ℃ into the penetrating condenser 12072 communicated with the second membrane module 12052 and forms a certain vacuum degree which is lower than the vacuum degree of the penetrating condenser 12072 introduced with a water source at 5 ℃ to 15 ℃ so as to assist the penetrating condensation; the second product enters the first evaporator 1203 of the third stage membrane separation module 123 through the first transmission pipeline 13, and heat exchange is performed in the first evaporator 1203 of the third stage membrane separation module 123; meanwhile, the first product subjected to the first heat exchange is introduced into the first heat exchanger 1201 of the first-stage membrane separation module 121 through the second transmission pipeline 14 communicated between the first-stage membrane separation module 121 and the second-stage membrane separation module 122, and undergoes second heat exchange with a first material flowing through the first heat exchanger 1201 subsequently, so that the first product separated by the first-stage membrane separation module 121 undergoes twice heat exchange, and the temperature is reduced to a temperature suitable for collection.

(3) And the basic working process of the third-stage membrane separation module 123: introducing a third material into the third stage membrane separation module 123, wherein the first batch of the third material passes through the first heat exchanger 1201 without heat exchange, the third material is conveyed to the first evaporator 1203, and is subjected to first heat exchange with a second product conveyed to the first evaporator 1203 by a first conveying pipeline 13 connected to the second stage membrane separation module 122 and the third stage membrane separation module 123, the third material is changed into a gaseous state and is conveyed to the first membrane module 12051 for first membrane separation treatment, the gaseous third material subjected to the first membrane separation treatment is divided into a third primary product and a fifth permeate vapor, the third primary product is conveyed to the second membrane module 12052 for second membrane separation treatment, and the fifth permeate vapor is conveyed to a permeate condenser 12072 communicated with the first membrane module 12051 for third permeate condensation treatment and corresponding permeate production, and when the fifth vapor is subjected to third permeate condensation, the cold water module 16 feeds water with the temperature of 5-15 ℃ into the osmotic condenser 12072 communicated with the first membrane module 12051, and the vacuum module 15 works to enable the osmotic condenser 12072 communicated with the first membrane module 12051 to form a certain vacuum degree so as to assist in osmotic condensation; the third primary product subjected to the second membrane separation treatment is divided into a third product and sixth permeate steam, wherein the sixth permeate steam is conveyed to a penetration condenser 12072 communicated with the second membrane module 12052 for third penetration condensation treatment and produces corresponding permeate, and when the sixth permeate steam is subjected to third penetration condensation, the cold water module 16 introduces water at-15 ℃ to-5 ℃ into the penetration condenser 12072 communicated with the second membrane module 12052 and forms a certain vacuum degree which is lower than that of the penetration condenser 12072 introduced with a water source at 5 ℃ to 15 ℃ so as to assist penetration condensation; the third product enters the first heat exchanger 1201 of the third stage membrane separation module 123 through the first transfer pipeline 13, and heat exchange is performed in the first heat exchanger 1201 of the third stage membrane separation module 123 (i.e., third heat exchange); meanwhile, the second product subjected to the first heat exchange is introduced into the first heat exchanger 1201 of the second-stage membrane separation module 122 through the second transmission pipeline 14 communicated between the second-stage membrane separation module 122 and the third-stage membrane separation module 123, and undergoes second heat exchange with a second material flowing through the first heat exchanger 1201 subsequently, so that the second product separated by the second-stage membrane separation module 122 undergoes twice heat exchange, and the temperature is reduced to a temperature suitable for collection.

(4) The first material, the second material and the third material which enter the membrane separation and purification device 10 in the first batch do not exchange heat when flowing through the first heat exchangers 1201 of the respective membrane separation modules 12, and the first material, the second material and the third material which flow in subsequently exchange heat in the first heat exchangers 1201 of the respective membrane separation modules 12 after the corresponding products are output in each stage of the membrane separation modules 12. The third product produced by the third stage membrane separation module 123 is in a gas-liquid mixed state after undergoing third heat exchange with the first heat exchanger 1201 flowing into the third stage membrane separation module 123, and then is cooled by the cooling module 18, so that the third product becomes a high-temperature liquid product and a liquid product with a temperature suitable for collection.

The above reference numerals (1) to (4) do not limit the order of operation of the membrane separation and purification apparatus 10.

In order to better illustrate the embodiments of the present invention, the following examples are further illustrative.

Example 1

Referring to fig. 2, fig. 3, and fig. 4 to fig. 5, a membrane separation and purification method for ethanol adopts the above membrane separation and purification apparatus 10, and the membrane separation and purification apparatus 10 has two stages of membrane separation modules 12 and a rectification module 21, where each stage of membrane separation module 12 includes a first membrane module 12051, a second membrane module 12052, and two permeate condensers 12072. The method specifically comprises the following steps:

introducing an ethanol material (namely, a first material) with the water content of 5 v/v% into a first-stage membrane separation module 121, controlling the flow rate to be 600kg/h, introducing steam with the gauge pressure of 0.5MPaG and the temperature of 160 ℃ into a heat supply module 11, setting the evaporation pressure in a first evaporator 1203 of the first-stage membrane separation module 121 to be 0.4MPa and the evaporation temperature to be 124.5 ℃, introducing low-temperature water with the temperature of 5 ℃ into a penetration condenser 12072 communicated with a first membrane module 12051 in the first-stage membrane separation module 121, and controlling the vacuum degree of the penetration condenser 12072 communicated with the first membrane module 12051 to be 3 kPa; chilled water at a temperature of-10 ℃ is introduced into the permeate condenser 12072 communicated with the second membrane module 12052, and the vacuum degree of the permeate condenser 12072 communicated with the second membrane module 12052 is controlled to be 0.3 kPa.

Meanwhile, ethanol material (namely, second material) with the water content of 5 v/v% is introduced into the second-stage membrane separation module 122, the flow rate is controlled to be 400kg/h, the evaporation pressure in the first evaporator 1203 in the second-stage membrane separation module 122 is set to be 0.2MPa, the evaporation temperature is set to be 108.2 ℃, low-temperature water with the temperature of 5 ℃ is introduced into the penetration condenser 12072 communicated with the first membrane module 12051, and the vacuum degree of the penetration condenser 12072 communicated with the first membrane module 12051 is controlled to be 3 kPa; chilled water at a temperature of-10 ℃ is introduced into the permeate condenser 12072 communicated with the second membrane module 12052, and the vacuum degree of the permeate condenser 12072 communicated with the second membrane module 12052 is controlled to be 0.3 kPa.

Circulating water is introduced into the membrane separation and purification device 10, and the circulating water flows through the first condenser 181, the second condenser 182 and the third condenser 214 respectively. The permeate produced by the first stage membrane separation module 121 and the permeate produced by the second stage membrane separation module 122 are passed to the rectification module 21 for rectification.

In the operation process of the membrane separation and purification device 10, collecting the wastewater generated by the second heat exchanger 211, and detecting the obtained wastewater, wherein the COD in the wastewater is about 42.7 mg/L; simultaneously collecting the ethanol product (namely, a first product) obtained by the first-stage membrane separation module 121 and the ethanol product (namely, a second product) obtained by the second-stage membrane separation module 122, and detecting the purity of the ethanol products obtained by the two parts, wherein the water content is 185ppm and 176ppm respectively; in addition, the azeotrope exiting the third condenser 214 is recycled.

By adopting the embodiment to separate and purify 10 tons of ethanol materials with the water content of 5 v/v%, the energy consumption can be saved by 40%, the steam amount introduced into the first-stage membrane separation module 121 is reduced by 0.21 ton/ton of products, the utilization rate of heat in the ethanol membrane separation and purification process is effectively improved, and the produced wastewater reaches the direct discharge standard of less than or equal to 50mg/L (GB 8978-1996).

Example 2

Referring to fig. 2, fig. 3, and fig. 4 to fig. 5, an isopropanol membrane separation and purification method adopts the above membrane separation and purification apparatus 10, and the membrane separation and purification apparatus 10 has two stages of membrane separation modules 12 and a rectification module 21, and each stage of membrane separation module 12 includes a first membrane module 12051, a second membrane module 12052, and two permeate condensers 12072. The method specifically comprises the following steps:

introducing an isopropanol material (namely, a first material) with the water content of 5 wt% into a first-stage membrane separation module 121, controlling the flow rate to be 600kg/h, introducing steam with the gauge pressure of 0.5MPaG and the temperature of 160 ℃ into a heat supply module 11, setting the evaporation pressure in a first evaporator 1203 of the first-stage membrane separation module 121 to be 0.4MPa and the evaporation temperature to be 129.6 ℃, introducing low-temperature water with the temperature of 5 ℃ into a penetration condenser 12072 communicated with a first membrane module 12051 in the first-stage membrane separation module 121, and controlling the vacuum degree of the penetration condenser 12072 communicated with the first membrane module 12051 to be 3 kPa; chilled water at a temperature of-10 ℃ is introduced into the permeate condenser 12072 communicated with the second membrane module 12052, and the vacuum degree of the permeate condenser 12072 communicated with the second membrane module 12052 is controlled to be 0.3 kPa.

Meanwhile, an isopropanol material (i.e., a second material) with the water content of 5 wt% is introduced into the second-stage membrane separation module 122, the flow rate is controlled to be 400kg/h, the evaporation pressure in the first evaporator 1203 in the second-stage membrane separation module 122 is set to be 0.2MPa, the evaporation temperature is set to be 112.8 ℃, low-temperature water with the temperature of 5 ℃ is introduced into the penetration condenser 12072 communicated with the first membrane module 12051, and the vacuum degree of the penetration condenser 12072 communicated with the first membrane module 12051 is controlled to be 3 kPa; chilled water at a temperature of-10 ℃ is introduced into the permeate condenser 12072 communicated with the second membrane module 12052, and the vacuum degree of the permeate condenser 12072 communicated with the second membrane module 12052 is controlled to be 0.3 kPa.

In the operation process of the membrane separation and purification equipment 10, collecting the wastewater generated by the second heat exchanger 211, and detecting the obtained wastewater, wherein the COD in the wastewater is about 39.1 mg/L; simultaneously collecting an isopropanol product (namely, a first product) obtained by the first-stage membrane separation module 121 and an isopropanol product (namely, a second product) obtained by the second-stage membrane separation module 122, and detecting the purities of the two isopropanol products, wherein the water contents are 100ppm and 100ppm respectively; in addition, the azeotrope exiting the third condenser 214 is recycled.

By adopting the embodiment to separate and purify 5 tons of ethanol materials with the water content of 5 wt%, the energy consumption can be saved by 40%, the steam amount introduced into the first-stage membrane separation module 121 is reduced by 0.2 ton/ton of products, the utilization rate of heat in the isopropanol membrane separation and purification process is effectively improved, and the produced wastewater reaches the direct discharge standard of less than or equal to 50mg/L (GB 8978-1996).

In summary, the membrane separation and purification apparatus 10 provided in the embodiment of the present invention has a high heat utilization rate when performing membrane separation and purification on azeotropic organic substances such as ethanol and isopropanol, and can effectively save energy consumption, and the generated wastewater can reach the standard of direct discharge.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. A membrane separation and purification method is characterized in that membrane separation and purification are carried out by adopting membrane separation and purification equipment;

the Nth-stage membrane separation module is used for introducing a product generated by the Nth-stage membrane separation module into the Nth-stage membrane separation module through the first transmission pipeline so as to carry out third heat exchange with a material introduced into the Nth-stage membrane separation module;

the membrane separation and purification method comprises the following steps:

each of the materials contained an organic azeotrope.

2. The membrane separation and purification method according to claim 1, wherein the latent heat value of the material entering the membrane separation module of the previous stage in the two adjacent stages of the membrane separation modules is controlled to be not less than the latent heat value of the material entering the membrane separation module of the next stage.

3. The membrane separation and purification method according to claim 1, wherein each stage of the membrane separation module comprises a first heat exchanger, a third transfer pipeline, a first evaporator, a fourth transfer pipeline and at least one membrane module which are sequentially communicated;

4. The membrane separation and purification method according to claim 3, wherein each stage of the membrane separation module further comprises a fifth transfer pipeline, and each stage of the membrane separation module comprises a first membrane module and a second membrane module;

5. The membrane separation purification method according to claim 3, wherein each stage of the membrane separation module further comprises a permeate condensing module in communication with the membrane module for subjecting permeate vapor produced by the membrane module to a permeate condensing process;

6. The membrane separation and purification method according to any one of claims 1 to 5, wherein the value of N is 2, 3 or 4;

7. The membrane separation and purification method according to any one of claims 1 to 5, wherein the membrane separation and purification equipment further comprises a cooling module for cooling the product subjected to the third heat exchange by the Nth stage membrane separation module;

8. The membrane separation and purification method according to any one of claims 1 to 5, wherein the first transmission line connected to the membrane separation module of the Nth stage comprises a first branch and a second branch;

and the second branch is communicated with the functional heat exchange module and the Nth-stage membrane separation module so as to lead the product subjected to the fourth heat exchange into the Nth-stage membrane separation module to carry out the third heat exchange.

9. The membrane separation and purification method according to claim 8, wherein the functional heat exchange module comprises any one of a rectification module and a molecular sieve adsorption module.

10. The membrane separation and purification method according to claim 9, wherein the rectification module comprises a second heat exchanger, a rectification column, a boiler, a third condenser, a seventh transfer line, an eighth transfer line, a ninth transfer line, a tenth transfer line and an eleventh transfer line;

11. The membrane separation and purification method according to claim 10, wherein the membrane separation and purification apparatus further comprises a circulating water module, the circulating water module being in communication with the third condenser;

12. The membrane separation and purification method according to claim 9, wherein the molecular sieve adsorption module comprises a third heat exchanger, a twelfth transfer pipeline, a second evaporator, a thirteenth transfer pipeline and at least one adsorption tower component which are communicated in sequence;

13. The membrane separation and purification method according to claim 12, wherein the molecular sieve adsorption module further comprises a fourteenth transfer line, and the fourteenth transfer line is communicated with the adsorption tower assembly and the third heat exchanger so as to lead the steam generated by the adsorption tower assembly to the third heat exchanger and carry out sixth heat exchange with the materials led to the third heat exchanger.

14. The membrane separation and purification method according to claim 9, wherein each stage of the membrane separation modules generates a penetrating fluid, and the penetrating fluid generated by any stage of the membrane separation modules or any kind of the materials is introduced into the rectification module; and (3) introducing penetrating fluid generated by any stage of membrane separation module or introducing any material into the molecular sieve adsorption module.

15. The membrane separation and purification method according to any one of claims 1 to 5, wherein the organic azeotrope is selected from any one of alcohols, ketones, aldehydes, ethers, and esters.