Gas countercurrent liquid-solid downer reactor

Abstract

The utility model discloses a gas countercurrent liquid-solid downer reactor and belongs to the technical field of chemical reactors. The reactor mainly comprises main structural units such as a liquid-solid inlet, a gas separator, a demister, a gas outlet, a gas baffle plate, a reactor main body, a gas inlet, a gas distributor and a liquid-solid outlet. In the reactor, gas moves upwards in the form of bubbles and is in countercurrent contact with a liquid phase and a solid phase, so that the interphase contact efficiency is improved, the liquid phase and the solid phase move downwards along a gravity field, backmixing is small, downward drag force is applied to the bubbles, and the gas retention time can be regulated and controlled by adjusting the apparent velocity of the liquid phase and the solid phase; the efficiency and the performance of the reactor are improved. The gas-liquid-solid three-phase reactor has the characteristics of simple structure, flexibility in operation, high interphase contact efficiency, small backmixing degree, excellent reactor performance and the like, can be widely applied to a gas-liquid-solid three-phase reaction process, and has a huge industrial application prospect.

Description

Technical Field

[0001] The utility model belongs to the technical field of chemical reactors, and relates to a gas-liquid-solid multiphase reactor, in particular to a new type of gas countercurrent liquid-solid descending bed reactor. Background Art

[0002] Gas-liquid-solid three-phase reactors are widely used in various fields such as petroleum, energy, biology, chemical industry, and pharmaceuticals. Traditional gas-liquid-solid three-phase reactors are more commonly stirred tanks, bubble towers, and slurry beds. Among them, stirred tanks are the most widely used gas-liquid-solid three-phase reactors. Different types of stirring paddles are installed in this type of reactor. Under the action of mechanical external force, the stirring paddles can achieve full mixing of the gas-liquid-solid three phases in the reactor. The shear force generated by the high-speed rotating stirring paddle can also break the bubbles in the reactor into small bubbles, increase the contact area between the liquid and solid phases, and achieve a higher degree of mixing and mass transfer rate between the liquid and solid phases. However, the stirred tank reactor requires external power equipment, and the high viscosity system has high requirements on the strength of the stirring rod material. In addition, the gas residence time in the reactor is short, and there is a large gas phase space in the upper part of the reactor, which is not suitable for process conditions that require high gas utilization or require timely gas discharge. In addition, the stirred tank reactor also has problems such as being unsuitable for high-pressure systems and difficult engineering amplification.

[0003] Compared with stirred tank reactors, bubble column reactors have the characteristics of simple structure, no mechanical stirring, and are suitable for high-pressure systems. The gas in the reactor exists in the form of bubbles, which not only increases the contact area between the gas and liquid phases, but also has a stirring effect, increasing the turbulence of the liquid and solid phases in the reactor, making the liquid and solid phases more evenly mixed, and improving the heat and mass transfer rates. However, the superficial velocity of the liquid phase in the bubble column reactor is almost close to zero, and special transmission, separation and filtration equipment are required, which increases the investment in the device.

[0004] The slurry bed reactor combines the advantages of the stirred tank reactor and the bubbling bed reactor. It has the advantages of simple structure, no need for mechanical rotating equipment, uniform catalyst distribution, large contact area between liquid and solid phases, high heat and mass transfer rate, and can also realize liquid and particle phase circulation operation. It has been widely used in heavy oil catalyst hydrogenation, low carbon hydrocarbon oxidation, industrial waste gas and wastewater treatment, etc. However, the slurry bed reactor is still a fully mixed flow reactor in essence, and the reaction efficiency needs to be further improved.

[0005] Although traditional stirred tanks, bubble towers and slurry bed reactors have been widely used in different fields and reaction processes, the above reactors all have problems such as high back-mixing degree, difficult to control gas residence time and low gas utilization rate. The stirred tank reactor is a typical fully mixed flow reactor. The liquid and solid phases in the reactor can be considered to be completely mixed and uniform, and the concentration, composition and temperature of the liquid phase in each local position of the reactor are the same. There is generally an uneven flow structure in the radial direction of the bubble tower reactor. The liquid phase moves upward in the central area of ​​the reactor and moves downward in the side wall area. The back-mixing is very serious, which is not conducive to the reaction and may even cause the generated products to further react, reducing the selectivity and yield of the product. The gas-liquid-solid three-phase slurry bed reactor generally relies on bubbles to achieve full mixing of the liquid phase and the solid phase. The circulation rate of the liquid phase in the local area is significantly higher than the feed rate of the liquid phase, and it is generally considered to be a fully mixed flow state in the reactor. According to the principles of chemical reaction engineering, the higher the degree of back-mixing, the larger the reactor volume is required to achieve the expected reaction effect, which invisibly increases the manufacturing cost of the equipment. In addition, whether it is a stirred tank, a bubble tower or a slurry bed reactor, the gas exists in the form of bubbles and moves upward under the action of buoyancy, in the process contacting and reacting with the liquid and solid phases until it reaches the top of the reactor and is discharged out of the system. In actual operation, it is difficult to control the size and movement speed of the bubbles in the reactor, resulting in a much shorter residence time of the gas phase than the liquid and solid phases, a mismatch between the residence time of the gas phase and the liquid and solid phases, an insufficient gas reaction, a large amount of unreacted gas that needs to be circulated, a significant increase in energy consumption, and even accumulation at the top of the reactor that can easily cause safety risks. Therefore, the precise control of the gas residence time in the gas-liquid-solid three-phase reactor is also one of the difficulties of existing multiphase reactors. Utility Model Content

[0006] In view of the problems of severe backmixing and difficult to control gas residence time in existing stirred tanks, bubbling towers and slurry bed reactors, the purpose of the utility model is to provide a gas countercurrent liquid-solid descending bed reactor, which is a gas-liquid-solid three-phase reactor. The gas is introduced from the bottom of the reactor, moves upward along the reactor in the form of bubbles and reacts in countercurrent contact with the liquid-solid phase introduced from the top of the reactor. The reactor can effectively solve the problems of severe backmixing and difficult to control gas residence time in traditional three-phase reactors. In addition, the utility model has the characteristics of simple structure, high phase contact efficiency, small liquid-solid phase backmixing, and precise control of gas residence time, and has great industrial application value.

[0007] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0008] The utility model provides a gas countercurrent liquid-solid down-bed reactor, which mainly comprises a liquid-solid inlet 1, a gas separator 2, a demister 3, a gas outlet 4, a gas baffle 5, a reactor body 6, a gas inlet 9, a gas distributor 7, and a liquid phase outlet 8; the inner top of the reactor body 6 is provided with the gas separator 2 and the demister 3 from top to bottom, and the gas separator 2 is connected with the gas outlet 4; the liquid-solid inlet 1 vertically penetrates the top of the reactor body 6, the gas separator 2 and the demister 3, one end of the liquid-solid inlet 1 is connected with a liquid-solid phase conveying device, and the other end extends into the interior of the reactor body 6, and the gas baffle 5 is arranged at the axial position of the end of the liquid-solid inlet 1 extending into the interior of the reactor body 6, the liquid-solid inlet 1, the gas separator 2, the demister 3 and the gas outlet 4 constitute a down-bed inlet structure with a gas separation function, and the down-bed inlet structure is connected with the upper part of the reactor body 6, and the gas distributor 7 is arranged on the cross section of the bottom of the reactor body 6, the gas distributor 7 is connected with the gas inlet 9, and the liquid-solid phase outlet 8 is arranged at the bottom of the reactor.

[0009] Based on the above technical solution, further, the reactor body 6 is cylindrical, with a body diameter of 20-10000 mm and a height of 0.5-40 m.

[0010] Based on the above technical solution, further, the liquid-solid inlet 1 is composed of a plurality of evenly distributed delivery pipes, the delivery pipes are arranged in parallel, the diameter of each delivery pipe is 10-200 mm, and the number is 2-1000.

[0011] Based on the above technical solution, further, the gas baffle 5 is a conical baffle or an arc baffle.

[0012] Based on the above technical solution, further, the demister 3 is one or a combination of two or more of a wire mesh demister, a baffle demister, a cyclone demister, an electric demister, a porous material demister, and a glass fiber demister.

[0013] Based on the above technical solution, further, the gas distributor 7 is one or a combination of two or more of a microporous type, a wind cap type, a cone cap type or a sintered tube type.

[0014] Based on the above technical solution, liquid level gauges are further installed at the top and bottom of the gas separator 2 to control the liquid interface to remain between the bottom of the liquid-solid inlet 1 and the demister 3 .

[0015] Based on the above technical solution, further, the apparent liquid velocity of the liquid-solid phase in the reactor body 6 is 0-500m / h, and the movement speed of the bubbles and the residence time of the gas in the reactor 6 can be controlled by adjusting the apparent liquid velocity of the liquid-solid phase.

[0016] Based on the above technical solution, further, the reactor body 6 is used within a pressure range of normal pressure-20 MPa and a temperature range of 0-500°C.

[0017] When the reactor described in the utility model is in operation, the gas is introduced from the gas inlet 9 at the bottom of the reactor body 6, and small bubbles are formed through the gas distributor 7. The liquid-solid phase is introduced from the liquid-solid inlet 1 at the top of the reactor. In the reactor body 6, the liquid-solid phase moves from top to bottom in a state similar to a plug flow, and the gas moves upward in the form of bubbles. The two are in countercurrent contact and chemical reaction occurs. In the reactor, the liquid-solid phase is in a gravity field and the back mixing is very small. By adjusting the apparent liquid velocity of the liquid-solid phase and combining the size of the bubble, the gas residence time can be precisely controlled to make the gas conversion more sufficient; at the top of the reactor, the gas is separated from the liquid-solid phase, and the liquid and particles carried by the gas are removed by the demister 3 and discharged from the system through the gas outlet 4 at the top of the reactor. The liquid-solid phase is discharged from the system through the liquid-solid outlet 8 at the bottom of the reactor body 6 to complete the reaction process. In the reactor body 6, the gas is in countercurrent contact with the liquid and solid phase, the contact area between the gas and liquid phase is large, and the contact efficiency is significantly improved.

[0018] In the utility model, the liquid and solid phases move downward along the gravity field, and the back mixing of the liquid and solid phases is extremely small, which is closer to a plug flow reactor. By adjusting the superficial flow rate of the liquid and solid phases, the gas residence time can also be accurately controlled, and the operation is more flexible and simple.

[0019] Compared with the prior art, the utility model has the following beneficial effects:

[0020] (1) The utility model has a simple structure and is flexible and easy to operate. It only requires adding a down-flowing bed inlet structure with a liquid-solid inlet and a gas separation function to the top of a conventional tubular reactor and adding a gas distributor to the bottom to realize the transformation of a gas countercurrent liquid-solid down-flowing bed reactor.

[0021] (2) In the gas countercurrent liquid-solid downward bed reactor of the utility model, the liquid and solid phases move from top to bottom along the gravity field, and the degree of backmixing is extremely small. A higher conversion rate can be achieved in a reactor of the same volume, or a desired conversion rate can be achieved in a reactor of smaller size, thereby improving the space utilization of the reactor.

[0022] (3) In the gas countercurrent liquid-solid downward bed reactor of the utility model, the gas contacts the liquid-solid phase in the form of bubbles in the bed. The bubbles in the bed are small and uniform in size. The gas phase contacts the liquid-solid phase in the countercurrent direction, which increases the turbulence of the two phases, improves the contact area between the gas and liquid phases and the mass transfer rate, and thus improves the efficiency of the reactor.

[0023] (4) In the gas countercurrent liquid-solid downward bed reactor described in the utility model, the gas moves upward along the reactor under the action of buoyancy, while the liquid and solid phases move downward, providing a downward drag force to the bubbles and reducing the movement speed of the bubbles. Therefore, the movement speed of the bubbles can be controlled by adjusting the apparent velocity of the downward movement of the liquid and solid phases, thereby achieving precise control of the gas residence time, making the gas in the reactor more fully utilized, the residence time of the liquid phase and the gas phase more matched, and improving the conversion rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to explain the present invention more clearly, the drawings related to the embodiments are briefly introduced below.

[0025] Figure 1 This is a schematic diagram of the structure of a gas countercurrent liquid-solid downward bed reactor of the utility model, in which: 1-liquid-solid inlet, 2-gas separator, 3-demister, 4-gas outlet, 5-gas baffle, 6-reactor body, 7-gas distributor, 8-liquid-solid outlet, 9-gas inlet. DETAILED DESCRIPTION

[0026] The present invention is described in detail below in conjunction with embodiments, but the embodiments of the present invention are not limited thereto. Obviously, the embodiments described below are only partial embodiments of the present invention. For those skilled in the art, other similar embodiments obtained without creative labor fall within the protection scope of the present invention.

[0027] Example 1

[0028] This embodiment provides a gas countercurrent liquid-solid down-flow bed reactor, the structure of which is as follows Figure 1As shown, the reactor mainly includes a liquid-solid inlet 1, a gas separator 2, a demister 3, a gas outlet 4, a gas baffle 5, a reactor body 6, a gas inlet 9, a gas distributor 7, and a liquid phase outlet 8; the reactor body 6 is cylindrical, and the gas separator 2 and the demister 3 are arranged on the inner top of the reactor body 6 from top to bottom, and the gas separator 2 is connected to the gas outlet 4; the liquid-solid inlet 1 adopts a multi-tube inlet structure, and the tube inlets are arranged in parallel and vertically penetrate the top of the reactor body 6, the gas separator 2 and the demister 3; one end of the liquid-solid inlet 1 is connected to the liquid-solid phase conveying equipment, and the other end extends into the reactor Inside the main body 6, a gas baffle 5 is arranged at the axial position of the end of the liquid-solid inlet 1 extending into the reactor main body 6. The gas baffle 5 is a conical baffle. The liquid-solid inlet 1, the gas separator 2, the demister 3 and the gas outlet 4 constitute a down-going bed inlet structure with a gas separation function, which can realize multiple functions such as stable transportation and uniform distribution of liquid and solid phases, and separation of gas and liquid and solid phases. The down-going bed inlet structure is connected to the upper part of the reactor main body 6, and a gas distributor 7 is arranged on the cross section of the lower part of the reactor main body 6. The gas distributor 7 is connected to a gas inlet 9, and a liquid-solid phase outlet 8 is arranged at the bottom of the reactor.

[0029] In this embodiment, a multi-tubular inlet structure is installed on the top of the reactor, which is composed of a uniformly distributed multi-tubular structure, which can transport the liquid-solid mixed phase downward to the upper part of the reactor body 6 and allow the liquid and solid phases to enter the reaction environment uniformly. In this embodiment, the diameter of the tubular inlet structure is 20 mm and the number is 12.

[0030] In this embodiment, a conical gas baffle 5 is installed at the lower part of the liquid-solid inlet 1 to prevent gas from entering the liquid-solid inlet 1 and hindering the liquid and solid phases from entering the reactor body 6 .

[0031] In this embodiment, a demister 3 is installed under the gas separator 2. The demister can be one or a combination of a wire mesh demister, a baffle demister, a cyclone demister, an electric demister, a porous material demister, and a glass fiber demister, preferably a wire mesh demister.

[0032] In this embodiment, a gas distributor 7 is installed at the lower part of the reactor body 6 to disperse the gas introduced into the reactor into small bubbles for contact reaction with the liquid and solid phases; the gas distributor 6 can be one or more of a microporous type, a wind cap type, a conical cap type or a sintered tube type, and in this embodiment it is a microporous gas distributor.

[0033] The apparent liquid velocity of the liquid-solid phase in the reactor is 1-500 m / h. The movement speed of the bubbles in the reactor can be regulated by the apparent liquid velocity of the liquid-solid phase. In this embodiment, the liquid velocity controlled by the liquid-solid phase is 50 m / h.

[0034] The reactor body 6 has a diameter of 20-10000 mm and a height of 0.5-40 m. In this embodiment, the inner diameter of the reactor body 6 is 200 mm and the height is 8 m.

[0035] The reactor can be used within a pressure range of normal pressure to 20 MPa and a temperature range of 0-500°C. In this embodiment, the operating pressure of the reactor is 3 MPa and the operating temperature is 100°C.

[0036] The working process of the above-mentioned gas countercurrent liquid-solid down-flow bed reactor is as follows:

[0037] The gas enters the reactor body 6 after being distributed by the gas distributor 7 from the gas inlet 9 at the bottom of the reactor body 6. After the gas distributor 7 disperses the gas into small bubbles, it moves upward along the reactor body 6 under the action of buoyancy, and the liquid and solid phases enter the top of the reactor body 6 from the top of the reactor body 6 through the multi-tubular liquid-solid inlet 1. This inlet structure can achieve the dual functions of liquid-solid phase transportation and uniform distribution. In the reactor body 6, the bubbles and the liquid-solid phases countercurrently contact and react chemically to achieve efficient conversion of the reactants. A conical gas baffle 5 is installed at the bottom of each liquid-solid phase inlet 1. The baffle can effectively prevent the gas from entering the liquid-solid inlet 1 tube and hinder the liquid-solid phase from entering the reactor body 6. The gas enters the gas separator 2 through the gap between the liquid-solid inlet conduits to separate the gas from the liquid-solid phase. Liquid level gauges are installed at the top and bottom of the gas separator 2 to control the liquid interface to remain between the bottom of the liquid-solid inlet 1 and the demister 3. After the gas is separated from the liquid and solid, the entrained droplets and particles are removed through the wire mesh demister 3 and discharged from the system or recycled through the gas outlet 4. The liquid-solid phase is discharged from the system by the liquid-solid phase outlet at the bottom of the reactor body 6 and enters the subsequent separation and product refining system. In the reactor body 6, the gas contacts the liquid-solid phase in the form of bubbles in countercurrent, and the turbulence degree between the three phases increases, which improves the contact efficiency between the phases in the reactor body 6. The liquid-solid phase moves downward along the gravity field, with little back mixing and better reactor performance. In addition, the downwardly moving liquid-solid phase exerts a downward drag on the bubble, and the residence time of the gas can be regulated by adjusting the apparent velocity of the liquid-solid phase, avoiding the problem that the gas residence time is short and difficult to regulate in the traditional three-phase reactor. Moreover, the gas countercurrent liquid-solid descending bed reactor does not require moving equipment, has a simple structure, is flexible to operate, and has huge industrial application prospects.

[0038] Based on the characteristics of the above-mentioned gas countercurrent liquid-solid down-flow bed reactor, the reactor described in the utility model is suitable for gas-liquid-solid three-phase reaction processes, such as heavy oil catalyst hydrogenation, olefin oxidation, alcohol oxidation, aldehyde oxidation esterification and other reaction processes, and has great industrial application value.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A gas countercurrent liquid-solid downward bed reactor, characterized in that: The gas countercurrent liquid-solid down-bed reactor comprises a liquid-solid inlet, a gas separator, a demister, a gas outlet, a gas baffle, a reactor body, a gas inlet, a gas distributor and a liquid phase outlet; the inner top of the reactor body is provided with a gas separator and a demister from top to bottom, and the gas separator is connected with the gas outlet; the liquid-solid inlet vertically penetrates the top of the reactor body, the gas separator and the demister, one end of the liquid-solid inlet is connected with a liquid-solid phase conveying device, and the other end extends into the interior of the reactor body, and a gas baffle is provided at the axial position of the end of the liquid-solid inlet extending into the interior of the reactor body, the liquid-solid inlet, the gas separator, the demister and the gas outlet constitute a down-bed inlet structure with a gas separation function, the down-bed inlet structure is connected with the upper part of the reactor body, a gas distributor is provided on the cross section of the bottom of the reactor body, the gas distributor is connected with the gas inlet, and the bottom of the reactor is provided with a liquid-solid phase outlet.

2. The gas countercurrent liquid-solid down-flowing bed reactor according to claim 1, characterized in that: The reactor body is cylindrical, with a diameter of 20-10000 mm and a height of 0.5-40 m.

3. The gas countercurrent liquid-solid down-flowing bed reactor according to claim 1, characterized in that: The liquid-solid inlet is composed of a plurality of evenly distributed delivery pipes, which are arranged in parallel, each of which has a diameter of 10-200 mm and a number of 2-1000.

4. The gas countercurrent liquid-solid down-flow reactor according to claim 1, characterized in that: The gas baffle is a conical baffle or an arc-shaped baffle.

5. The gas countercurrent liquid-solid down-flowing bed reactor according to claim 1, characterized in that: The demister is one or a combination of two or more of a wire mesh demister, a baffle demister, a cyclone demister, an electric demister, a porous material demister, and a glass fiber demister.

6. The gas countercurrent liquid-solid down-flowing bed reactor according to claim 1, characterized in that: The gas distributor is one of microporous type, wind cap type, cone cap type or sintered tube type or a combination of two or more thereof.

7. The gas countercurrent liquid-solid down-flowing bed reactor according to claim 1, characterized in that: Liquid level gauges are installed at the top and bottom of the gas separator to control the liquid interface to remain between the bottom of the liquid-solid inlet and the demister.

Images