CN1171667C - multistage loop reactor - Google Patents

Abstract

A multi-stage circulation reactor for various gas-liquid two-phase and gas-liquid-solid three-phase chemical reactions comprises a tower body 1, a guide shell 2 and a gas distributor 3, wherein the guide shell 2 is arranged in the tower body 1, and the gas distributor 3 is arranged at the bottom of the guide shell 2. Once bubbles are generated at the bottom of the tower, the fluid in the guide shell moves upwards to form a flow state that the large circulation is sleeved with the small circulation; the gas-liquid contact in the reactor is full, the gas content is high, the local gas content is uniformly distributed, the mass transfer rate is high, and the gas dissolution speed is high; for a gas-liquid-solid three-phase reaction system, solid particles are uniformly distributed in the reactor, and local accumulation or deposition cannot occur; the heat transfer effect is good, the heat exchange speed between the fluid and the wall of the reactor is high, the temperature in the reaction system is uniformly distributed due to the full mixing of the materials in the reactor, and the temperature difference of different areas is very small, so that the reactor can be widely applied to various gas-liquid and gas-liquid-solid reaction processes such as an oxidation reaction process, a hydrogenation reaction process, a hydrocracking process, a coal liquefaction hydrogenation process, a fermentation process, a hydrocarbon processing reaction process, an activated sludge sewage treatment process and the like.

Description

multistage loop reactor

technical field

The utility model relates to a reactor used for various gas-liquid two-phase and gas-liquid-solid three-phase chemical reactions, belonging to the field of chemical engineering, specifically, a multi-stage loop reactor.

Background technique

At present, gas-liquid or gas-liquid-solid reactors are widely used in chemical industry, petrochemical industry and other industrial processes. Generally, bubble reactors or stirred tank reactors are used for gas-liquid or gas-liquid-solid reactions. These two types of traditional reactors have low efficiency and high energy consumption, and their application fields are limited by the reaction system. In these reaction processes, effective mixing of gas-liquid or gas-liquid-solid, good dispersion of gas and solid particles in the liquid phase, high-speed directional flow of fluid, and high mass transfer rate are important properties of the reactor. Especially for processes where mass transfer is the controlling step of the overall reaction and involving liquid or solid phase catalysts, in order to speed up the overall reaction process, some form of mechanical agitation must be used to increase the mass transfer rate and interphase mixing. The use of mechanical stirring not only consumes a lot of energy, but also is difficult to achieve for reaction systems with high temperature, high pressure, and strong corrosion.

The inner loop reactor developed based on the bubble reactor is to introduce a guide tube in the bubble reactor to make the fluid circulate in the reactor, thereby enhancing the gas-liquid or gas-liquid-solid mixing As a result, the overall mass transfer rate of the reactor is also higher than that of the traditional bubble reactor.

However, there is a serious defect in the traditional inner loop reactor, that is, in the annulus area between the draft tube and the inner wall of the reactor, because the buoyancy force of the larger bubbles is greater than the drag force, the liquid circulation The generated drag force cannot drag down the larger bubbles, resulting in a small gas holdup in the annulus, a low utilization rate of the reactor, and a low overall efficiency of the reactor.

Contents of the invention

The object of the present invention is to propose and develop a multi-stage loop reactor on the basis of the traditional bubble reactor. This multi-stage loop reactor adopts multi-stage guide tubes and internal components of different structures, which completely solves the defects of small gas holdup and low reaction efficiency in the annulus of traditional inner loop reactors. It has excellent hydromechanical properties and gas-liquid Or gas-liquid-solid mixing is good, the total mass transfer rate is high, and the temperature distribution in the reactor is uniform, which can be widely used in various gas-liquid or gas-liquid-solid chemical reaction processes.

The present invention is achieved like this:

It includes a tower body 1, a guide tube 2, and a gas distributor 3. The tower body 1 has a guide tube 2, and the bottom of the guide tube 2 has a gas distributor 3.

The present invention also adopts following technical scheme:

The ratio of the total height of the tower body 1 to the inner diameter of the reactor is 3-12, and the ratio of the diameter of the draft tube 2 to the inner diameter of the reactor is 0.3-0.9.

The guide tube 2 is a whole, which can be one section or more than two sections; the section spacing is 5 to 50 cm, connected with rigid ribs;

The guide tube 2 is provided with an opening area along the axial direction.

The opening on the guide tube 2 can be one or more than one.

There is an internal member 4 on the guide tube 2 .

The distance between the lower end of the draft tube 2 and the bottom of the reactor is 10-100 cm; the distance between the upper end of the draft tube 2 and the liquid surface of the reaction liquid is 10-200 cm.

The reactor has built-in multi-stage guide tubes 2, and the guide tubes of all levels are coaxially fixed to each other, leaving gaps between them.

There can be 1-6 guide tubes 2, each guide tube 2 is parallel to the axis and placed in the reactor, each guide tube 2 is equipped with a gas distributor 3.

The characteristics of the multistage loop reactor of the present invention are:

① The multi-stage loop reactor of the present invention is composed of a tower body, a draft tube, internal components and a gas distributor. The guide tube is single or multi-segment, and various forms of combination and/or addition of internal components are used between the segments;

②The reaction gas enters the aeration tower through the gas distributor. Once the bubbles are generated at the bottom of the tower, due to the jet force and density difference of the gas, the bubble cluster will drive the surrounding liquid to move upwards, and will perform rapid circulation around each section of the guide tube and the overall guide tube, forming a large circulation sleeve and a small circulation. flow state;

③Due to sufficient gas-liquid contact, high gas holdup, and uniform distribution of local gas holdup, the mass transfer rate is high and the gas dissolution rate is fast; for the gas-liquid-solid three-phase reaction system, the solid particles are evenly distributed in the reactor , without local accumulation or deposition.

④ Good heat transfer effect: due to the rapid directional movement of the fluid in the reactor annulus, the heat exchange rate between the fluid and the reactor wall is high, and at the same time, due to the sufficient mixing of the materials in the reactor, the temperature distribution in the reaction system is uniform, and the temperature in different regions The temperature difference is very small.

Description of drawings

Accompanying drawing 1 is one of structure diagram of multistage circulation aeration tower of the present invention;

Accompanying drawing 2 is the second structural diagram of multistage circulation aeration tower of the present invention;

Accompanying drawing 3 is the structure figure three of multistage circulation aeration tower of the present invention;

Accompanying drawing 4 is the structure drawing four of multistage circulation aeration tower of the present invention;

Accompanying drawing 5 is the structural diagram of the internal member (baffle plate) between the guide cylinder of the present invention;

Accompanying drawing 6 is the fluid flow state figure in the reactor structure shown in Figure 1;

Accompanying drawing 7 is the fluid flow state figure in the reactor structure shown in Figure 2;

Accompanying drawing 8 is the fluid flow state diagram in the reactor structure shown in Figure 3;

Accompanying drawing 9 is the fluid flow state figure in the reactor structure shown in Figure 4;

Accompanying drawing 10 is the structure and flow state diagram of multi-stage loop flow reactor with multiple guide tubes.

specific implementation

The present invention is described in detail below in conjunction with accompanying drawing:

As shown in Figure 1, it consists of three parts: the tower body 1, the guide tube 2, and the gas distributor 3. The guide tube can be one section, two sections or multiple sections, and the sections are connected by rigid ribs.

As shown in Figure 2: it consists of four parts: the tower body, the guide tube, the internal member 4, and the gas distributor. The guide tube can be one-stage, two-stage or multi-stage.

As shown in Figure 3: it consists of three parts: the tower body, the guide tube 2 with openings, and the gas distributor. There may be one, two or more opening areas along the axial direction of the guide tube.

As shown in Figure 4, it consists of four parts: the tower body, the guide tube, the internal components, and the gas distributor. The guide cylinder can be one-stage, two-stage or multi-stage, and an opening area is arranged at a certain position on each section of the guide cylinder.

As shown in Figure 6, the fluid moves quickly and directionally around each section of the guide tube and the entire guide tube in the tower, forming a movement pattern of a large circulation sleeve and a small circulation.

In the multistage loop reactor of the present invention, the reaction gas enters through the gas distributor 3 from the bottom of the multistage loop reactor, and immediately produces a large number of bubbles around the gas distributor 3, that is, forms a dilute phase around the gas distributor 3 The density of the dilute-phase zone is lower than that of the surrounding liquid. Under the action of the density difference and the impulsive force of the gas entering the reactor, the bubbles and the liquid in the dilute-phase zone move upward in the guide tube, and between the guide tube 2 and the inner wall of the reactor The liquid in the annulus area immediately flows to the gas distributor to replenish, thereby creating a rapid circulation movement. When the fluid moves upwards to the top of the first guide tube 2, under the action of the baffle plate and/or the static pressure difference, a part of the fluid will flow from the gap between the first and second guide tubes to the annular gap, And with the fluid flowing downward in the annulus; a part of the fluid will still move upward into the second guide tube and continue to move upward. Continue in this way until the fluid moves to the top of the last nozzle, and then returns to travel down the annulus.

Obviously, in the above-mentioned flow in the reactor, several small circulations are formed along each section of the draft tube 2, and a large circulation is formed along the entire draft tube, that is, a flow state of a large circulation sleeve and a small circulation is formed. In this way, there is little difference in the degree of turbulence inside the reactor, the gas holdup is evenly distributed, and the bubbles are evenly distributed along the axial direction of the reactor; for the gas-liquid-solid reaction system, the solid particles are evenly distributed. Due to the multi-stage circulation movement of the gas in the reactor, although the average residence time remains unchanged, the distance that the gas flows before it escapes from the reactor is longer, and at the same time, the gas-liquid is fully contacted and mixed, so the gas is in the liquid phase. High solubility.

The reactor is composed of four parts: tower body 1, internal member 4, draft tube 2 and bottom gas distributor 3. There is no mechanical stirring part in the reactor of the present invention, the fluid circulates quickly and directional in the reactor, the gas-liquid or gas-liquid-solid mixing is good, the reactor has no dead angle, and the mass transfer rate is high; Function, forming a rapid movement mode of circulation or large circulation sleeve small circulation in the reactor, the bubbles and solid particles are evenly distributed, the gas holdup and solid holdup are uniform, and the solid particles will not accumulate in any part; because in the reactor The rapid circulation movement of the internal fluid, the temperature distribution in the reactor is uniform, and the heat exchange between the fluid and the reactor wall is good. The present invention can be widely used in oxidation reaction process, hydrogenation reaction process, hydrocracking process, coal liquefaction hydrogenation process, fermentation process, hydrocarbon processing reaction process and activated sludge sewage treatment process, etc. various gas-liquid and gas-liquid- during the solid reaction.

The multi-stage guide tube can be divided into two, three or several stages according to the height of the reactor. The multi-stage guide cylinder can have different forms, including: the guide cylinder is divided into multiple sections, and the interval between the sections is 5-50 cm; ; The guide tube is a section, and holes are punched in different parts, and the opening rate is determined by the total length of the guide tube.

A gas distributor is installed at the lower part of the draft tube in the reactor.

Several specific embodiments of the present invention are introduced below.

Example 1: Gas-liquid reaction

Reactor: primary loop reactor; volume: 50 liters

Chemical reaction: α-pyrrolidone + acetylene → vinylpyrrolidone

Reaction temperature: 170°C; Reaction pressure: 12atm; Catalyst: KOH

Continuous operation, liquid space velocity: 0.25h ^-1

Example 2: Oxidation reaction

Reactor: two-stage loop reactor; volume: 1m ³

Chemical reaction: p-nitroethylbenzene + air → p-nitroacetophenone

Reaction temperature: 140°C; Reaction pressure: 5atm; Catalyst: acetate

Intermittent operation, reaction time: 11h

Example 3: Oxidation Reaction

Reactor: two-stage loop reactor; volume: 20 liters

Chemical reaction: isopropyl toluene + oxygen → CHP

Reaction temperature: 106°C; Reaction pressure: 5.6atm

Intermittent operation, reaction time 4h

Example 4: Heavy Oil Catalytic Hydrocracking

Reactor: two-stage loop reactor; reactor volume: 20m ³

Reaction temperature: 450°C; Reaction pressure: 130atm

Continuous operation, liquid space velocity 1h ^-1 .

Embodiment 5: industrial sewage treatment

Reactor: two-stage loop reactor, the tower body is made of carbon steel; volume: 25m ³ .

The sewage is petrochemical comprehensive wastewater, mainly containing benzene, toluene, styrene, epichlorohydrin and cyclohexanone, etc., with a COD of 960-1020mg/l, and adopts continuous operation, the ambient temperature is 6-20°C, and the water temperature in the tower is 18-25°C, the residence time of wastewater in the tower is 6 hours, the daily treatment capacity is 100 tons of wastewater/day, the concentration of activated sludge is 3-6g/l, and the COD of the treated water is reduced to 80-140. COD removal rate is 86.2-91.6%.

Claims (9)

1. multi-stage circular flow reactor comprises body of the tower (1), guide shell (2), gas distributor (3), it is characterized in that: guide shell (2) is arranged in the body of the tower (1), and gas distributor (3) is arranged at the bottom of guide shell (2).

2. multi-stage circular flow reactor according to claim 1 is characterized in that: body of the tower (1) height overall is 3-12 with the ratio of reactor inside diameter, and guide shell (2) diameter is 0.3-0.9 with the ratio of reactor inside diameter.

3. multi-stage circular flow reactor according to claim 1 is characterized in that: guide shell (2) is an integral body, can be one section, also can be more than two sections, 5～50 centimetres of intersegmental distances link to each other with the rigidity rib, the intersegmental deflection plate that adds can be gone up punching at every section guide shell (2).

4. according to claim 1 or 3 described multi-stage circular flow reactors, it is characterized in that: guide shell (2) is provided with aperture area vertically.

5. according to claim 1 or 4 described multi-stage circular flow reactors, it is characterized in that: the perforate on the guide shell (2) can be a place, also can be more than the place.

6. multi-stage circular flow reactor according to claim 1 is characterized in that: inner member (4) is arranged on the guide shell (2).

7. multi-stage circular flow reactor according to claim 1 is characterized in that: the distance of the following end distance reactor bottom of guide shell (2) is 10-100 centimetre; The liquid level 10-200 of the last end distance reaction liquid of guide shell (2) centimetre.

8. multi-stage circular flow reactor according to claim 1 is characterized in that: this device is built-in with multilevel deflector tube (2), and is mutually coaxial fixing between the guide shells at different levels, between leave the space.

9. multi-stage circular flow reactor according to claim 1 is characterized in that: guide shell (2) can have 1～6, and the axis of each guide shell (2) is parallel to each other, places in the reactor, all is equipped with gas distributor (3) under the every guide shell (2).

Images