CN110961042A

CN110961042A - Film separator

Info

Publication number: CN110961042A
Application number: CN201811040367.0A
Authority: CN
Inventors: 戴金龙
Original assignee: Taixing Hongwei Electromechanical Environmental Protection Technology Co ltd
Current assignee: Taixing Hongwei Electromechanical Environmental Protection Technology Co ltd
Priority date: 2018-09-07
Filing date: 2018-09-07
Publication date: 2020-04-07

Abstract

The invention relates to a membrane separator suitable for heterogeneous catalytic reaction systems using fine catalyst particles. The most obvious characteristic of the reactor is that two groups of membrane tubes form a membrane reactor, wherein one group of membrane tubes is used as a membrane distributor to control the feeding concentration distribution of reaction raw materials, so that the local concentration of reactants can be prevented from being too high, the utilization rate of the reaction raw materials is effectively improved, and the occurrence of side reactions is avoided or reduced, and the other group of membrane tubes is used as a membrane separator to control the solid-liquid separation in a reaction system, so that a catalyst is kept in a cavity of the membrane tubes, and the reaction and the catalyst separation are carried out simultaneously. The reactor can control the flow field distribution of feeding and discharging, improve the conversion rate and selectivity of reaction and the utilization rate of raw materials, reduce the reaction cost, and has the advantages of short process flow, high reaction efficiency, low energy consumption, low investment and the like.

Description

Film separator

Technical Field

The invention relates to a membrane separator, which adopts a membrane pipe as a membrane distributor, a membrane separator and a reactor. Is suitable for a heterogeneous catalytic reaction system using fine catalyst particles, and belongs to chemical equipment.

Background

Heterogeneous catalytic reactions are catalytic reactions in which gaseous or liquid reactants are reacted with a solid catalyst at a two-phase interface. The process at least comprises three continuous steps of chemical adsorption of reactants on the surface of the catalyst, conversion of adsorbed intermediates and desorption of products. The chemical process using heterogeneous catalytic reaction as a research object generally uses process parameters such as temperature, pressure, flow, liquid level and components as controlled variables, and at present, there is no report that the distribution change of a feed flow field of a reaction raw material is used as a main control process parameter.

Heterogeneous catalytic reactions often use fine particles as catalysts, and conventional separation process techniques often require batch operations, and it is difficult to completely separate such catalysts from the product, greatly affecting the performance of the target product. The membrane separation technology established on the basis of materials can realize the separation of fine catalysts and products and realize the continuity of the reaction process. The current advanced membrane reaction device realizes the in-situ separation of fine particle catalysts by assembling a membrane separator outside or inside the reactor, and simultaneously realizes the continuous operation of the heterogeneous catalytic reaction process. The integrated suspension bed inorganic membrane reactor disclosed in patent ZL02138439.8 and 200410041687.X uses such technology to enable the heterogeneous catalytic reaction process and the membrane separation process to be carried out simultaneously in the same reactor. However, in the above patent, the membrane tubes only perform a filtering function, do not function as a reactor per se, and do not consider the influence of the variation of the field distribution of the feed and discharge streams on the reaction result.

Disclosure of Invention

The invention aims to provide a membrane separator, wherein the membrane functions as a membrane distributor, a membrane separator and a membrane reactor, the reaction performance is improved by controlling the distribution of the feeding and discharging flow fields of the heterogeneous catalytic reaction when the heterogeneous catalytic continuous reaction is carried out, the reaction and the separation are carried out simultaneously, the reaction process is short, and the structure of the reactor is more compact.

The technical scheme of the invention is as follows: a membrane separator features that two groups of membrane tubes are used to form membrane reactor, which is used as reactor. One group of membrane tubes play the roles of a membrane distributor and a reactor, and the feed concentration distribution of reaction raw materials is controlled by adjusting the feed flow rate and the pore diameter of the membrane tubes; the other group of membrane tubes play the roles of a membrane separator and a reactor, products are separated from reaction materials by permeating the membrane, and the catalyst is retained in the reactor to continuously participate in the reaction, so that the process is continuously carried out.

The specific technical scheme of the invention is as follows: a membrane separator is composed of a membrane distributor 5, a membrane separator 8 and a pump 7 for providing circulating power, wherein reaction raw materials and a catalyst form an internal circulation in a reactor; wherein both ends of the membrane distributor 5 and the membrane separator 8 are sealed with a sealing assembly 11.

The membrane material adopted by the membrane distributor 5 and the membrane separator 8 is organic material, inorganic material or organic-inorganic composite material; the average pore diameter of the membrane is 2nm-10 μm.

The number of the membrane tubes in the membrane distributor 5 and the membrane separator 8 is determined according to the property of a reaction system, the property of a membrane and the magnitude of reaction flow, and generally, the membrane distributor 5 and the membrane separator 8 are preferably composed of 1-100 membrane tubes respectively; the membrane tube is a straight tube or a coil tube.

The feeding system is connected with a membrane distributor 5 and consists of

constant flow pumps

2 and 3 and reaction raw

material storage tanks

1 and 4; the membrane separator 8 is connected with a discharging system, and the discharging system consists of a vacuum suction pump 9 and a product storage tank 10; when heterogeneous catalytic reaction is carried out, a reaction material oxidant (such as hydrogen peroxide) in a storage tank 4 enters a reactor through a constant flow pump 3 and a membrane distributor 5, other reaction materials (such as ammonia water, acetone and tert-butyl alcohol mixed liquor) in the storage tank 1 enter the reactor through a constant flow pump 2, a product flows out of the reactor through a membrane separator 8 and enters a product storage tank 10 through a discharge pump 9, the feeding flow rate and the discharge flow rate are the same, the reaction and the separation are carried out while the reaction is carried out, catalyst particles do not go out of a reaction system, and the reaction process is continuously carried out; the flow range of the reaction mixed liquid in the membrane tube is 3-60 mL/min, and the reaction temperature range is 0-200 ℃.

The number of membrane tubes of the membrane distributor 5 and the membrane separator 8 is determined according to the reaction flow, the microstructure of the membrane and the properties of the heterogeneous catalytic reaction; the inlet of the constant flow pump 3 can be at any position on the membrane distributor, and the outlet of the vacuum suction pump 9 on the membrane separator can also be at any position on the membrane separator.

The pump 7 providing the circulating power is a corrosion-resistant peristaltic pump or a centrifugal pump.

Has the advantages that:

the invention provides a film separator, which controls the feeding concentration of reaction raw materials through a film distributor, effectively improves the conversion rate and selectivity of the reaction and the utilization rate of the raw materials, and reduces the reaction cost; the membrane tube is used as a reactor, catalyst particles are trapped in the reactor to continuously participate in the reaction, liquid-phase materials penetrate through the membrane and flow out of the reactor through high pressure or negative pressure, and the process is continuously carried out. The corrosion-resistant peristaltic pump or centrifugal pump is used for providing power to enable substances in a reaction system to circularly flow, and the flow field distribution of feeding and discharging can be controlled by controlling the rotating speed and the structure of a membrane material, so that the membrane can keep higher permeation flux, the area of the required membrane is reduced, and the feasibility of the system is improved.

Drawings

FIG. 1 is a schematic of a tubular membrane reactor employing one membrane tube as the membrane distributor and one membrane tube as the membrane separator.

In the figure, 1 and 4 are raw material storage tanks; 2. 3 is a constant flow pump; 5 is a membrane distributor; 6 is a closed outer sleeve; 7 is a peristaltic pump or a corrosion-resistant centrifugal pump; 8 is a membrane separator; 9 is a vacuum suction pump; 10 is a product storage tank; and 11 is a sealing ring.

Detailed Description

As shown in figure 1, the tubular membrane reactor mainly comprises two stainless steel membrane tubes with the average pore diameter of 100nm and a peristaltic pump 7, wherein the stainless steel membrane tube 5 is a membrane distributor, the stainless steel membrane tube 8 is a membrane separator, reaction materials form internal circulation during reaction, and the spaces where reaction circulating liquid is located are calculated as the volume of the reactor. Taking the reaction of TS-1 catalyzing the ammoxidation of acetone to prepare acetone oxime as an example: firstly putting 3.6g of TS-1 catalyst into a reactor, sealing, pumping 17.0g of metered acetone and 83.6g of tert-butyl alcohol into a reaction kettle by using a pump, starting a peristaltic pump to form internal circulation, then heating, starting

constant flow pumps

2 and 3 to add ammonia and hydrogen peroxide into the reactor when the reaction temperature reaches 65 ℃, controlling the ratio of ammonia to ketone to be 1.5, the ratio of oxygen to ketone to be 1.5, the feeding time to be 1h, and reacting for 2h after feeding. Then the constant flow pump 2 is started to add ammonia and acetone into the reactor, the constant flow pump 3 adds hydrogen peroxide into the reactor, the aminoketone ratio is controlled to be 1.5, the oxygen-ketone ratio is controlled to be 1.5, the reaction is continuously carried out, and the hydrogen peroxide concentration distribution in the feeding material is controlled by the membrane distributor 5, so that the conversion rate and the selectivity of the reaction can be improved; the vacuum suction pump 9 for discharging is opened while feeding again to start continuous discharging, the feeding flow and the discharging flow are both controlled to be 3mL/min, and the reading of a vacuum meter is about 480mmH when the reaction is balanced₂O, the reaction conversion rate can be stabilized to be more than 94%, and the reaction selectivity can be stabilized to be more than 98%.

Claims

1. A membrane separator consists of a membrane distributor (5), a membrane separator (8) and a pump (7) for providing circulating power, wherein reaction raw materials and a catalyst form an internal circulation in a reactor; wherein the two ends of the membrane distributor (5) and the membrane separator (8) are sealed by a sealing component (11).

2. The reactor according to claim 1, characterized in that the membrane distributor (5) and the membrane separator (8) are made of organic materials, inorganic materials or organic-inorganic composite materials; the average pore diameter of the membrane is 2nm-10 μm.

3. The reactor according to claim 1, characterized in that the membrane distributor (5) and the membrane separator (8) are each composed of 1 to 100 membrane tubes; the membrane tube is a straight tube or a coil tube.

4. The reactor according to claim 1, characterized in that the feeding system is connected with the membrane distributor (5), and the feeding system is composed of constant flow pumps (2), (3) and reaction raw material storage tanks (1), (4); the membrane separator (8) is connected with a discharging system, and the discharging system consists of a vacuum suction pump (9) and a product storage tank (10); when the heterogeneous catalytic reaction is carried out, the oxidant of the reaction material in the storage tank (4) enters the reactor through the constant flow pump (3) and the membrane distributor (5), the other reaction material in the storage tank (1) enters the reactor through the constant flow pump (2), and the product flows out of the reactor through the membrane separator (8) and enters the product storage tank (10) through the discharge pump (9); the feeding flow rate and the discharging flow rate are the same, the reaction and the separation are carried out at the same time, the catalyst particles can not be discharged out of the reaction system, and the reaction process is continuously carried out; the flow range of the reaction mixed liquid in the membrane tube is 3-60 mL/min, and the reaction temperature range is 0-200 ℃.

5. Reactor according to claim 1, characterized in that the pump (7) providing the circulation power is a corrosion-resistant peristaltic or centrifugal pump.