CN208182888U - Reactive distillation-film device coupling production ethyl acetate in high purity device - Google Patents

Abstract

The utility model relates to a device for coupling production of high-purity ethyl acetate by adopting reactive distillation-membrane equipment, including reactant acetic acid and ethanol entering into a reactive distillation tower to carry out esterification reaction in a reaction zone to generate ethyl acetate and water, Ethyl acetate and water will form the lowest azeotrope; the lowest azeotrope formed by ethyl acetate and water will be extracted from the top of the rectification tower in the form of positive pressure steam through the separation of the rectification section of the reactive distillation tower, and the rest of the water and The unreacted excess acetic acid will be extracted from the bottom of the distillation column through the stripping section of the reactive distillation column; the positive pressure steam of the lowest azeotrope enters the membrane equipment, and is separated by the membrane module. The membrane outlet is ethyl acetate steam, and the water phase Enter the negative pressure side through the membrane module. The reactive distillation-membrane equipment coupled separation method removes water thoroughly and has stable product quality, which can effectively solve the problems of high energy consumption and low purity in the existing production process. The system has no waste discharge, energy saving and environmental protection, and has a good application prospect.

Description

A device for producing high-purity ethyl acetate coupled with reactive distillation-membrane equipment

technical field

The utility model belongs to the technical field of chemical production technology and equipment, and mainly relates to a device for producing high-purity ethyl acetate coupled with reactive distillation-membrane equipment.

Background technique

Ethyl acetate is one of the most common, most widely used and frequently demanded acetate products, which can be used as organic chemical raw materials and organic solvents. At this stage, with the rapid development of the world economy, the requirements for environmental protection are becoming increasingly strong. The high price and high toxicity of benzene solvents can no longer meet the requirements for the production of coatings, inks, and adhesives as solvents. Therefore, as high-grade benzene solvents As an alternative product, the demand for ethyl acetate is increasing year by year.

There are mainly four types of ethyl acetate produced in the world, namely: acetic acid and ethanol esterification method, ethanol dehydrogenation method, ethylene acetic acid method and acetaldehyde condensation method. At present, the most important method of producing ethyl acetate in my country is the esterification method of acetic acid and ethanol. This method uses sulfuric acid as a catalyst to directly esterify ethyl acetate, and then dehydrates and fractionates to refine it to obtain ethyl acetate products.

However, the azeotropic system of ethanol and water and ethyl acetate and water exists in the ethyl acetate production system, which makes the subsequent separation difficult. To obtain high-purity ethyl acetate, it needs to go through multi-tower cycle operations such as phase separation, extraction, and rectification. , the overall process needs to consume a lot of heat, and the initial equipment investment and later operation investment are relatively large, which cannot meet the market demand.

Utility model content

In view of the above-mentioned problems and defects, the purpose of this utility model is to provide a device for producing high-purity ethyl acetate by reactive distillation-membrane equipment coupling, and to prepare high-purity ethyl acetate using the reactive distillation-membrane equipment coupling method provided by the utility model. Ethyl acetate has a high reaction conversion rate, can effectively control the reaction temperature, shorten the reaction residence time, eliminate the azeotropic situation between ethanol and water, and has the advantages of simple process flow, low equipment investment, convenient operation, stable product quality and low energy consumption. lower advantages.

The technical scheme that the utility model takes is:

A reactive distillation-membrane equipment coupled device for producing high-purity ethanol, including a reactive distillation tower, a membrane device, a cooler, a partial condenser at the top of the tower, and a reboiler; The bottom of the rectification tower is connected to the inlet of the bottom reboiler through a pipeline, the gas phase outlet of the bottom reboiler is connected to the gas return port at the bottom of the reactive distillation tower, and the liquid phase outlet of the bottom reboiler is passed through the bottom material extraction pump It is connected with the cooler, and the outlet of the heat exchanger is connected with the bottom water extraction pipeline; the extraction outlet of the top material of the reactive distillation tower 3 is connected with the gas phase inlet of the membrane equipment through the partial condenser at the top of the tower, and the outlet of the permeation side of the membrane equipment is connected with the gas phase inlet of the membrane equipment. The top water production pipeline is connected; the outlet on the retention side of the membrane device is connected to the top high-purity ethyl acetate production pipeline.

And, described reactive distillation column is made up of rectification section, reaction section and stripping section, or reactive distillation column is made up of rectification section and reaction section; Rectification section and stripping section column internals are packing or tray ; The reaction section is loaded with a solid acid catalyst.

Moreover, two liquid phase feed ports or one liquid phase feed port are arranged on the reaction section of the reactive distillation column.

Moreover, the membrane device is provided with a pervaporation membrane, and the pervaporation membrane is a water-permeable molecular sieve membrane, preferably a NaA membrane.

Advantage and positive effect of the utility model:

The utility model adopts reactive distillation-membrane equipment coupling to produce high-purity ethyl acetate device, which has the advantage of simplifying the complex process of acetic acid and ethanol esterification and ethyl acetate refining and purification to nearly one reactive distillation tower and one Membrane equipment saves equipment investment.

The utility model adopts reactive distillation-membrane equipment coupling method to produce high-purity ethyl acetate by utilizing the advantages of reactive distillation and membrane separation process to timely take the reaction product out of the reaction zone to effectively improve the conversion rate of the esterification reaction and eliminate ethanol Azeotrope with water; use membrane to separate ethyl acetate and water azeotrope, reduce the energy consumption of the subsequent separation azeotropic system without introducing a third substance, and greatly reduce the operating cost of high-purity ethyl acetate production. An efficient and environmentally friendly production separation technology.

Features of the used reactive distillation tower internals of the utility model: 1, the used reactive distillation tower patent number is: 200810052269.9, publication number CN101306256A can accelerate the esterification reaction of acetic acid and ethanol to generate ethyl acetate, and can provide enough The gas-liquid contact surface completes the task of mass transfer and separation, so that the reaction products ethyl acetate and water leave the reaction section quickly, ensuring a high concentration of reactants and a low concentration of products in the reaction section. 2. The patent number of the internal parts of the reactive distillation tower is: 200810052269.9, which has a long service life and does not need to be replaced frequently.

Description of drawings

Figure 1 is a schematic diagram of the reactive distillation-membrane equipment coupling process flow diagram of high-purity ethyl acetate, wherein the reactive distillation tower is composed of rectification section 4, reaction section 5 and stripping section 6, and the reaction section of the reactive distillation tower is designed There are two liquid phase feed ports.

Figure 2 is a schematic diagram of the reactive distillation-membrane equipment coupling process flow diagram of high-purity ethyl acetate, wherein the reactive distillation column is composed of a rectification section 4, a reaction section 5 and a stripping section 6, and the catalytic reaction section of the reactive distillation column is set There is a mixed liquid phase feed port.

Figure 3 is a schematic diagram of the reactive distillation-membrane equipment coupling process flow diagram of high-purity ethyl acetate, wherein the reactive distillation column is composed of a rectification section 4 and a reaction section 5, and the reaction section of the reactive distillation column is equipped with two liquid phase feeds mouth.

Figure 4 is a schematic diagram of the reactive distillation-membrane equipment coupling process flow diagram of high-purity ethyl acetate, wherein the reactive distillation column is composed of a rectification section 4 and a reaction section 5, and the reaction section of the reactive distillation column is provided with a mixed liquid phase inlet feed port.

Detailed ways

The utility model will be further described in detail below in conjunction with the accompanying drawings and specific examples. The following examples are only descriptive, not restrictive, and cannot limit the protection scope of the utility model.

The reactive distillation-membrane equipment coupled production device of high-purity ethyl acetate provided by the utility model has the following structure: as shown in Figure 1, it includes a reactive distillation tower 3, a membrane device 8, a cooler 10, and a partial condenser at the top of the tower 7. Reboiler 9; feed ports for raw material acetic acid and ethanol are arranged on the reactive distillation tower to be connected with the raw material feed pipeline, and the bottom of the reactive distillation tower 3 is connected to the inlet of the bottom reboiler 9 through a pipeline, and the bottom of the tower is reboiled The gas phase outlet of the device 9 is connected with the reactive distillation tower 3, the liquid phase outlet of the tower bottom reboiler 9 is connected with the cooler 10 through the tower bottom material extraction pump, and the heat exchanger outlet is connected with the bottom water extraction pipeline; The extraction outlet of the top material of the rectification tower 3 is connected to the gas phase inlet of the membrane equipment 8 through the partial condenser 10 at the top of the tower, and the outlet of the permeation side of the membrane equipment 8 is connected to the top water production pipeline; the outlet of the retention side of the membrane equipment 8 is connected to the top The high-purity ethyl acetate production pipeline is connected.

Wherein as shown in Figure 1, reactive distillation tower 3 is made up of rectification section 4, reaction section 5, stripping section 6, and reaction section is provided with two liquid phase feed ports and is applied in embodiment 1;

Or as shown in Figure 2, it is made up of rectifying section 4, reaction section 5, stripping section 6, and reaction section is provided with a liquid phase mixing inlet and is applied in the embodiment 2;

Or as shown in Figure 3, be made up of rectifying section 4, reaction section 5, and reaction section is provided with two liquid-phase feeding ports and is applied in embodiment 3;

Alternatively, as shown in Figure 4, it consists of a rectifying section 4 and a reaction section 5, and the reaction section is provided with a liquid-phase mixing feed port for use in Example 4.

The acetic acid raw material and the ethanol raw material feed inlet are set at the catalytic reaction section 5 in the catalytic reaction rectification tower 3, and the reaction product water and unreacted excess acetic acid are extracted from the bottom of the reaction rectification tower, and the formation of ethyl acetate and water is the lowest. The gas phase of the azeotrope is extracted from the gas phase outlet of the condenser 7 at the top of the tower, and then transported to the membrane device 8. The water in the steam is separated from the ethyl acetate through the pervaporation membrane to obtain the permeate and dehydrated ethyl acetate. The permeate is obtained from the permeate The side outlet is extracted.

The device and method of the utility model are characterized in that the production of ethyl acetate by the method of the utility model has higher purity, lower product loss, no need for subsequent separation and purification operations, and lower overall energy consumption of the process.

The method of operation with the above-mentioned device is as follows:

(1) Acetic acid and ethanol solution are fed into the reactive distillation column 3 respectively from two liquid-phase feed ports on the reaction section 5 of the reactive distillation column 3 or from a liquid-phase feed port on the reaction section 5 of the reactive distillation column Mix feed and react;

(2) The ethyl acetate and water produced by the reaction form the lowest azeotrope, and the reaction zone is separated through the rectification section 4 of the reactive distillation tower, and is extracted from the top of the tower by the partial condenser 7 at the top of the tower;

(3) The steam produced at the top of the tower is extracted from the gas phase outlet at the top of the tower and transported to the membrane device 8. The water in the steam is separated from the ethyl acetate through the pervaporation membrane to obtain the permeate and dehydrated ethyl acetate, and the permeate is exported from the permeate side mining;

(4) The remaining water and unreacted excess acetic acid are separated from the reaction zone through the stripping section 6 of the reactive distillation tower, and are transported from the bottom reactor of the reactive distillation tower to the cooler 10 through the tower reboiler 9, and then cooled by the cooler 10 Then it is extracted from the outlet of the cooler.

The operating conditions of the reactive distillation tower in the above method are: the preferred range of the working pressure of the reactive distillation tower is absolute pressure 0.5-1 atm; the mass ratio of the feed acetic acid and ethanol of the reactive distillation tower is 1.3-6.5:1; The amount of catalyst used in the distillation column is 20-300kg/m ³ ; the ratio of the quality of the partially cooled steam of the partial condenser 7 at the top of the tower to the quality of the steam produced by the condenser is in the range of 0.1-10:1.

The steam from the top of the reactive distillation tower directly enters the pervaporation membrane for pervaporation dehydration. The permeation side of the membrane equipment is operated under negative pressure. The operating pressure is 100-600kPa, and the operating temperature is the temperature corresponding to the saturated vapor pressure of the system. -20°C; the pervaporation membrane is equipped with a water-permeable molecular sieve membrane, preferably NaA membrane.

The technology and equipment of the utility model are widely applicable to the preparation of high-purity ethyl acetate by the esterification reaction of acetic acid and ethanol. In order to better illustrate the advantages of the utility model in terms of product purity, conversion rate and energy consumption, four applications are selected. Examples are used to illustrate, but do not limit the scope of application of this technology and equipment.

Example 1

The utility model method is used for ethanol and acetic acid esterification ethyl acetate process under acidic conditions, is the same as the process described in the utility model, including reactive distillation tower 3, membrane equipment 8, cooler 10, tower top part condensation Device 7, reboiler 9, wherein because this process needs both tower top purification and tower bottom purification, so this catalytic reaction rectification column is shown in Figure 1, by rectifying section 4, catalytic reaction section 5 and stripping section 6 composition. Ethanol and acetic acid enter the reactive distillation column from two liquid-phase feed ports on the reaction section 5 respectively, and the feed port of ethanol is below the acetic acid.

The absolute pressure of the reactive distillation column is 0.5 atm, the mass ratio of feed acetic acid to ethanol is 1.3:1, the catalyst dosage of the reactive distillation column is 50kg/m ³ , the quality of the cooling steam of the condenser at the top of the column is the same as that produced by the condenser The steam mass ratio is 10. The pressure difference on both sides of the membrane device is 100kPa.

After the above process, the purity of the main product ethyl acetate can reach 99.6%, the yield of ethyl acetate can reach more than 99.8%, and the energy consumption can be reduced by more than 75% compared with the traditional process.

Example 2

The utility model method is used for ethanol and acetic acid esterification ethyl acetate process under acidic conditions, is the same as the process described in the utility model, including reactive distillation tower 3, membrane equipment 8, cooler 10, tower top part condensation Device 7, reboiler 9, wherein because this process needs both tower top purification and tower bottom purification, so this catalytic reaction rectification tower is shown in Figure 2, by rectifying section 4, catalytic reaction section 5 and stripping section 6 composition. After ethanol and acetic acid are mixed, they enter into the reactive distillation column from a liquid phase feed port on the reaction section 5.

The absolute pressure of the reactive distillation tower is 1 atm, the mass ratio of feed acetic acid to ethanol is 2.6, the catalyst dosage of the reactive distillation tower is 100kg/m3, the ratio of the cooling steam quality of the partial condenser at the top of the tower to the quality of the steam produced at the top of the tower for 5. The pressure difference on both sides of the membrane device is 300kPa.

After the above process, the purity of the main product ethyl acetate can reach 99.9%, the yield of ethyl acetate can reach more than 99.9%, and the energy consumption can be reduced by more than 74% compared with the traditional process.

Example 3

The utility model method is used for ethanol and acetic acid esterification ethyl acetate process under acidic conditions, is the same as the process described in the utility model, including reactive distillation tower 3, membrane equipment 8, cooler 10, tower top part condensation Device 7, reboiler 9, wherein because this process only needs tower top purification, so this catalytic reaction rectification tower is shown in Figure 3, is made up of rectification section 4, catalytic reaction section 5 and stripping section 6. Ethanol and acetic acid enter the reactive distillation column from two liquid-phase feed ports on the reaction section 5 respectively, and the feed port of ethanol is below the acetic acid.

The absolute pressure of the reactive distillation tower is 0.7atm, the mass ratio of feed acetic acid to ethanol is 3.9, the catalyst consumption of the reactive distillation tower is 200kg/m3, the cooling steam quality of the tower top part condenser and the steam quality of the condenser The ratio is 1. The pressure difference on both sides of the membrane equipment is 400kPa.

After the above process, the purity of the main product ethyl acetate can reach 99.7%, the yield of ethyl acetate can reach more than 99.8%, and the energy consumption can be reduced by more than 74% compared with the traditional process.

Example 4

The utility model method is used for ethanol and acetic acid esterification ethyl acetate process under acidic conditions, is the same as the process described in the utility model, including reactive distillation tower 3, membrane equipment 8, cooler 10, tower top part condensation Device 7, reboiler 9, wherein because this process only needs tower top purification, so this catalytic reaction rectification tower is shown in Figure 4, is made up of rectification section 4, catalytic reaction section 5 and stripping section 6. After ethanol and acetic acid are mixed, they enter into the reactive distillation column from a liquid phase feed port on the reaction section 5.

The absolute pressure of the reactive distillation column is 1 atm, the mass ratio of feed acetic acid to ethanol is 6.5, the catalyst consumption of the reactive distillation column is 300kg/m3, the ratio of the cooling steam quality of the top partial condenser to the steam quality of the condenser is 0.1. The pressure difference on both sides of the membrane equipment is 600kPa.

After the above process, the purity of the main product ethyl acetate can reach 99.5%, the yield of ethyl acetate can reach more than 99.6%, and the energy consumption can be reduced by more than 73% compared with the traditional process.

A method and device for producing high-purity ethanol by rectification-membrane equipment coupling proposed by the utility model have been described through preferred embodiments, and those skilled in the art can clearly understand the content, spirit and scope of the utility model without departing from the utility model. The equipment and technological process described herein are modified or appropriately modified and formed to realize the technology of the utility model. In particular, it should be pointed out that all similar substitutions and modifications will be obvious to those skilled in the art, and they are all considered to be included in the spirit, scope and content of the present invention.

Claims (4)

1. a kind of reactive distillation-film device coupling production ethyl acetate in high purity device, it is characterised in that: including reactive distillation Tower, film device, cooler, tower top fractional distilling tube, reboiler；Material inlet, reactive distillation column are set on reactive distillation column Tower bottom is connect with tower bottom reboiler import by pipeline, and tower bottom reboiler gaseous phase outlet is connected with reactive distillation column tower bottom gas returning port It connects, tower bottom reboiler liquid-phase outlet is connected by materials at bottom of tower extraction pump with cooler, and heat exchanger exit and bottom water produce Pipeline is connected；3 tower top material of reactive distillation column extraction mouth is connected by tower top fractional distilling tube with film device gas phase import, The outlet of film device per-meate side is connected with top water extraction pipeline；Film device retains the outlet and top high-purity acetic acid second of side Ester extraction pipeline is connected.

2. reactive distillation according to claim 1-film device coupling production ethyl acetate in high purity device, feature exist In: the reactive distillation column is made of rectifying section, conversion zone and stripping section or reactive distillation column is by rectifying section and conversion zone group At；Rectifying section and stripping section tower internals are filler or tower tray；Conversion zone filling solid acid catalyst.

3. reactive distillation according to claim 1-film device coupling production ethyl acetate in high purity device, feature exist In: two liquid phase feeding mouths or a liquid phase feeding mouth are set on the conversion zone of the reactive distillation column.

4. reactive distillation according to claim 1-film device coupling production ethyl acetate in high purity device, feature exist In: infiltrating and vaporizing membrane is equipped in the film device, infiltrating and vaporizing membrane is permeable molecular screen membrane.