A liquid membrane reactor for gas-liquid reaction and a method of gas-liquid reaction

Abstract

The present application relates to a kind of liquid membrane reactor for gas-liquid reaction and the method of gas-liquid reaction.The reactor includes reactor shell and the several reaction tubes for carrying out chemical reaction arranged in reactor shell;The reactor shell is filled with reaction gas between reaction tube;Reaction liquid film is formed on the outer wall of the reaction tube;The inside of the reaction tube is used for the flow of heat conducting medium circulation.The reactor of the present application can improve the gas-liquid mass transfer efficiency under high viscosity system;Effectively prevent the liquid flooding phenomenon under high gas speed;While it can solve the problem of high viscosity material blockage, easy to clean and maintain.

Description

Technical Field

[0001] This invention belongs to the field of chemical reactor equipment technology, specifically relating to a liquid film reactor for gas-liquid reaction and a method for gas-liquid reaction. Background Technology

[0002] Traditional gas-liquid reactions often employ bubble column reactors, static mixers, or packed bed reactors, but these reactors have certain defects and limitations.

[0003] Traditional bubble column reactors are widely used due to their simple structure and lack of moving parts. However, when processing high-viscosity materials, the increased liquid viscosity inhibits bubble breakage and surface renewal, leading to severe bubble coalescence and a sharp decrease in specific surface area. Simultaneously, high gas velocities are damped by high viscosity during liquid circulation, resulting in severe backmixing of the gas and liquid phases and reduced reaction selectivity. Furthermore, the high viscosity system leads to a low heat transfer coefficient, making heat removal difficult. While static mixers or packed beds with structured packing or static mixing elements can cut bubbles, in high-viscosity liquid phases, the rate of bubble re-coalescence is extremely rapid, making it difficult to maintain dispersion. More importantly, high-viscosity materials easily clog distribution channels or packing gaps (forming "channeling"), leading to a sharp increase in bed pressure drop, short equipment operating cycles, and difficult cleaning. Summary of the Invention

[0004] In view of the problems existing in the prior art, the purpose of the present invention is to provide a liquid film reactor for gas-liquid reaction, including a reactor shell and a plurality of reaction tubes disposed in the reactor shell for carrying out chemical reaction; The reactor shell and the reaction tube are filled with reaction gas; a reaction liquid film is formed on the outer wall of the reaction tube; and the inside of the reaction tube is used for the flow of heat-conducting medium.

[0005] Based on the above scheme, an upper tube sheet is provided at the upper end of the reaction tube; a lower tube sheet is provided at the lower end of the reaction tube; a liquid distributor is provided on the side of the reaction tube near the upper tube sheet; the liquid distributor includes a support plate and a liquid distribution pipe that penetrates the support plate; the reaction tube passes through the liquid distribution pipe and forms a gap between the reaction tube and the liquid distribution pipe, and the reaction liquid enters the gap between the liquid distribution pipe and the reaction tube from the upper end of the liquid distribution pipe and moves downward along the outer wall of the reaction tube by gravity.

[0006] Based on the above scheme, the upper tube sheet, lower tube sheet, and support plate are all disposed on the inner wall of the reactor shell; a reaction liquid injection chamber is formed between the upper tube sheet and the support plate; and a reaction chamber is formed between the lower tube sheet and the support plate.

[0007] Based on the above scheme, the wall of the reaction liquid injection chamber is provided with an inlet for injecting the reaction liquid into the reaction liquid injection chamber; the lower tube sheet is provided with an outlet for outputting the reaction product from the reaction chamber.

[0008] Based on the above scheme, it also includes a heat transfer medium inlet for inputting heat transfer medium into the reaction tube and a heat transfer medium outlet for outputting heat transfer medium from the reaction tube.

[0009] Based on the above scheme, the bottom of the reaction chamber is provided with a gas inlet for inputting reaction gas into the reaction chamber, and the top of the reaction chamber is provided with a first exhaust port for discharging gas from the reaction chamber.

[0010] Based on the above scheme, a second exhaust port for discharging gas from the reaction liquid injection chamber is provided on the wall of the reaction liquid injection chamber.

[0011] Based on the above scheme, the reaction tube is a straight tube and / or a spiral tube.

[0012] Based on the above scheme, the gap between the reaction tube and the liquid distribution tube is 0.3-0.8 mm.

[0013] The present invention also provides a method for gas-liquid reaction, comprising the following steps: The reaction liquid enters the reaction liquid injection chamber through the inlet; when the height of the reaction liquid in the reaction liquid injection chamber is greater than the upper edge of the distribution pipe, the liquid begins to enter the gap between the distribution pipe and the reaction pipe; under the action of gravity, the liquid flows down along the outer wall of the reaction pipe and finally enters the reaction chamber, where the reaction chamber contains reaction gas injected from the gas inlet; the reaction takes place in the reaction chamber; the reaction products are output from the outlet; during the reaction, a heat-conducting medium is introduced into the reaction pipe.

[0014] Advantages of the reactor of this invention: (1) Significantly improves gas-liquid mass transfer efficiency in high-viscosity systems: The reactor of this invention utilizes an array of oil-guiding coils or the outer wall of a threaded straight pipe to guide the material to form a continuous, thin-layered, large-area, and constantly renewed liquid film. When the gas passes upward from the lower end of the reactor through the gaps in the coils (i.e., spiral wound pipes) or threaded straight pipes, it makes perpendicular cross-flow contact with the liquid film, resulting in frequent rupture and reconstruction of the gas-liquid interface, effectively suppressing the coalescence of bubbles in high-viscosity liquids. Compared with bubble column reactors and static mixers or packed bed reactors, this invention can improve the volumetric mass transfer coefficient by 30%-80% under the same viscosity conditions, and is especially suitable for strongly exothermic chlorination and some absorption processes that require high viscosity and high mass transfer.

[0015] (2) Effectively prevents flooding at high gas velocities and offers high operational flexibility: Because the reactor of this invention has no packing material or narrow distribution channels in the shell side, but only an open gas flow channel formed by coils or spiral straight tube arrays, the gas flow resistance is extremely low. Even under conditions of large gas throughput (e.g., empty tower gas velocity of 0.5-2.0 m / s), the gas can still be uniformly distributed in the gaps between the coils or spiral straight tubes, avoiding localized gas phase penetration or flooding. Simultaneously, the liquid film thickness can be independently controlled by adjusting the liquid inlet flow rate, resulting in a wide gas-liquid ratio adjustment range and operational flexibility of 30%-120% of the design load, adapting to different process fluctuations.

[0016] (3) Completely solves the clogging problem of high-viscosity materials and is easy to clean and maintain: In the reactor of this invention, after the material enters through the large-channel liquid distributor, it spreads and forms a film on the surface of the coil and hanger only by gravity and surface tension, effectively avoiding the generation of narrow gaps or dead corners. After long-term operation, if there are deposits on the surface of the reaction tube, they can be quickly restored by shell flushing or chemical cleaning. The cleaning cycle is 3-5 times longer than that of traditional packed towers, significantly reducing downtime maintenance costs.

[0017] (4) Achieve precise in-situ heat exchange and temperature control, reduce viscosity and remove heat of reaction: The reaction tube is both a liquid film formation carrier and an internal heat exchange element. A heat transfer medium (heat transfer oil, hot water or coolant) is introduced into the tube side to directly heat the liquid film to reduce the initial viscosity of the material (e.g., from 10 Pa·s to 0.5 Pa·s), greatly improving fluidity; it can also remove heat of reaction in time for exothermic reactions, avoiding local overheating that could lead to side reactions or deactivation of heat-sensitive materials. The overall temperature control accuracy can reach ±1℃, which is far superior to the temperature control capability of traditional jacketed or external heat exchangers.

[0018] (5) Reduced energy consumption and operating costs: The reactor of this invention does not require mechanical stirring paddles or high-power gas distribution devices, and relies solely on gravity and gas source pressure to drive gas-liquid flow. The shell-side gas pressure drop is typically below 200 Pa / m, far lower than that of bubble column reactors and static mixers or packed bed reactors with the same throughput; at the same time, there are no moving parts, avoiding mechanical seal leakage and stirring motor energy consumption, and the overall energy consumption is reduced by 40%-60% compared with mechanically stirred reactors.

[0019] (6) Simple and compact structure, easy to modularize and scale up: The array reaction tubes of the reactor of the present invention can be straight tubes or coils of standard specifications and integrated into modules by flanges or welding. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the reactor structure of the present invention; Figure 2 This is a structural schematic diagram of the reactor of the present invention from a cross-sectional perspective (only one reaction tube is shown). Figure 3 This is a schematic diagram of the reactor structure of the present invention (excluding the reactor shell); Figure 4 This is a schematic diagram of a second structural embodiment of the reactor of the present invention (excluding the reactor shell). Figure 5 This is a structural schematic diagram of the reactor of the present invention from a cross-sectional perspective (the reaction tube is a straight tube). Figure 6 This is a schematic diagram of the series gas-liquid reaction system of the present invention. Detailed Implementation

[0021] The terminology used in this invention, unless otherwise specified, generally has the meanings commonly understood by those skilled in the art. The invention is further described in detail below with reference to specific embodiments and data. The following embodiments are merely illustrative and are not intended to limit the scope of the invention in any way.

[0022] Example 1

[0023] like Figure 1-5 As shown, the present invention provides a liquid film reactor for gas-liquid reaction, comprising a reactor shell 1 and a plurality of reaction tubes 2 disposed within the reactor shell 1 for carrying out chemical reactions; The reactor shell 1 and the reaction tube 2 are filled with reaction gas; a reaction liquid film is formed on the outer wall of the reaction tube 2; and the interior of the reaction tube 2 is used for the flow of heat-conducting medium.

[0024] As a specific implementation, an upper tube sheet 2-1 is provided at the upper end of the reaction tube 2; a lower tube sheet 2-2 is provided at the lower end of the reaction tube 2; a liquid distributor 10 is provided on the side of the reaction tube 2 near the upper tube sheet 2-1; the liquid distributor 10 includes a support plate 11 and a liquid distribution pipe 12 that penetrates the support plate 11; the reaction tube 2 passes through the liquid distribution pipe 12 and forms a gap with the liquid distribution pipe 12, and the reaction liquid enters the gap between the liquid distribution pipe 12 and the reaction tube 2 from the upper end of the liquid distribution pipe 12 and moves downward along the outer wall of the reaction tube 2 by gravity.

[0025] As a specific implementation, the gap between the reaction tube 2 and the liquid distribution tube 12 is 0.3-0.8 mm, preferably 0.5 mm.

[0026] In one specific implementation, the upper tube sheet 2-1, the lower tube sheet 2-2, and the support plate 11 are all disposed on the inner wall of the reactor shell 1; a reaction liquid injection chamber 1-2 is formed between the upper tube sheet 2-1 and the support plate 11; and a reaction chamber 1-1 is formed between the lower tube sheet 2-2 and the support plate 11.

[0027] As a specific implementation, the wall of the reaction liquid injection chamber 1-2 is provided with an inlet 1-21 for injecting reaction liquid into the reaction liquid injection chamber 1-2; the lower tube plate 2-2 is provided with an outlet 2-21 for outputting the product after reaction in the reaction chamber 1-1.

[0028] As a specific implementation, it also includes a heat transfer medium inlet 3 for introducing heat transfer medium into the reaction tube 2 and a heat transfer medium outlet 4 for discharging heat transfer medium from the reaction tube 2. The heat transfer medium is water, heat transfer oil, or coolant.

[0029] As a specific implementation, the bottom of the reaction chamber 1-1 is provided with a gas inlet 1-11 for inputting reaction gas into the reaction chamber 1-1, and the top of the reaction chamber 1-1 is provided with a first exhaust port 1-12 for discharging gas from the reaction chamber 1-1.

[0030] As a specific implementation, the wall of the reaction liquid injection chamber 1-2 is provided with a second exhaust port 1-22 for discharging the gas inside the reaction liquid injection chamber 1-2.

[0031] As a specific implementation, the reaction tube 2 is a straight tube and / or a spirally wound tube.

[0032] The reaction tube 2 has threads on its wall.

[0033] To facilitate process observation and process development, a viewing window (such as a pressure-resistant glass sight glass, etc.) can be configured on the shell 1 of the reactor of this invention. Figure 1 As shown in the figure (no further labels), the uniformity of the liquid film, the gas-liquid contact state, and possible channeling phenomena can be directly observed in the laboratory or pilot-scale stage, facilitating rapid optimization of operating parameters. Compared with bubble column reactors and static mixers or packed bed reactors, the reactor of this invention has unique advantages in process scale-up and mechanism research.

[0034] The reactor of this invention is suitable for gas-liquid reactions. In use, liquid enters the reaction liquid injection chamber 1-2 through the inlet 1-21. When the height of the reaction liquid in the reaction liquid injection chamber 1-2 is greater than the upper edge of the distribution pipe 12, the liquid begins to enter the gap between the distribution pipe 12 and the reaction pipe 2. Due to the small gap between the distribution pipe 12 and the reaction pipe 2, the liquid flows downwards along the outer wall of the reaction pipe 2 under the action of gravity and finally enters the reaction chamber 1-1. The reaction chamber 1-1 contains reaction gas injected through the gas inlet 1-11. To accommodate different reaction requirements, a heat-conducting medium (water, heat-conducting oil, or coolant) is introduced into the reaction pipe 2.

[0035] If venting is required when injecting the reaction liquid, the second vent port 1-22 can be opened. If venting is required when injecting the reaction gas, the first vent port 1-12 can be opened to release the air. Alternatively, unreacted gas or gas produced by the reaction can be released through the first vent port 1-12 after the reaction.

[0036] Compared to existing reactors, the reactor of this invention has advantages in reactions involving high-viscosity liquids and gases, such as the following reaction systems: Liquid high-viscosity fatty acids react with chlorine gas in a gas-liquid chlorination reaction Reaction materials: Liquid material: High-viscosity stearic acid (saturated higher fatty acid, semi-solid at room temperature, high-viscosity liquid at medium and high temperatures, commonly used industrial modified chlorination raw material); Gaseous material: Industrial chlorine (Cl2); Reaction type: gas-liquid electrophilic substitution chlorination reaction, strongly exothermic reaction; Reaction process: Heat transfer oil is introduced into the tube side (reaction tube 2) as the heat exchange medium. The array-type heat exchange tube bundle (reaction tube 2) is evenly arranged in the shell side reaction zone. High-viscosity stearic acid molten material enters from the liquid inlet 1-21 at the top of the reactor, and then enters the gap between the liquid distribution pipe 12 and the reaction tube 2. Finally, it forms a continuous and uniform thin liquid film from top to bottom along the outer surface of the reaction tube 2. Chlorine gas enters from the gas inlet 1-11 at the bottom of the reactor and rises countercurrently from bottom to top, making full contact with the high-viscosity fatty acid liquid film flowing from top to bottom. The gas-liquid two-phase chlorination reaction is completed in the shell side closed reaction chamber 1-1. The heat exchange medium carries away a large amount of heat released by the reaction in real time, and the reaction temperature is precisely controlled. The chlorinated product liquid after the reaction is collected by gravity to the liquid outlet 2-21 at the bottom of the reactor and is continuously discharged. The excess chlorine gas that did not fully participate in the reaction and the trace amount of by-product acid gas are collected and recycled through the first exhaust port 1-12.

[0037] Example 2

[0038] Based on the liquid film reactor in Example 1, such as Figure 6 As shown, the present invention provides a series gas-liquid reaction system, including several liquid film reactors 100 as in Embodiment 1. The several liquid film reactors are connected in series. Two adjacent liquid film reactors 100 are provided with a gas-liquid separator 200 for recovering the reaction products of the previous liquid film reactor 100 and separating the reaction products into gas and liquid, while inputting the liquid after gas-liquid separation into the next liquid film reactor 100.

[0039] Specifically, the liquid raw material enters the reaction system through the inlet 1-21 of the first liquid film reactor 100, the reaction gas enters through the gas inlet 1-11 of each liquid film reactor 100, and the heat transfer medium enters the reaction tube 2 of each liquid film reactor 100 through the heat transfer medium outlet 4. After the reaction is completed in the first liquid film reactor 100, the reacted liquid enters the first gas-liquid separator 200 through the outlet 2-21 of the first liquid film reactor 100. The liquid separated by the first gas-liquid separator 200 enters the second liquid film reactor 100 through the inlet 1-21 of the second liquid film reactor 100, and so on. After the reaction is carried out in sequence, the final product is obtained by separation in the last gas-liquid separator 200.

[0040] The series-connected gas-liquid reaction system of this invention increases the reaction length by connecting reactors in series, thereby increasing the reaction residence time. Multiple modules connected in series form multi-stage liquid film contact, adapting to different reaction depth requirements. This structure is easy to manufacture, install, and maintain, and has low metal consumption, reducing equipment investment costs by 20%-30% compared to towers of the same scale.

[0041] Example 3

[0042] Based on the reactor of Example 1, the present invention provides a gas-liquid reaction method, which includes the following steps: Step 1: Pre-reaction preparation and system checks: Reactor tightness check: Air tightness tests were performed separately for the shell side and tube side. Preparation of the heat transfer medium system: Start the heat transfer oil or coolant circulation system and ensure that there is no air resistance in the tubes. Feeding system cleaning: Inlet pipes, liquid distributors, and drain outlets are unobstructed and free of residue blockages. Instrument calibration: temperature, pressure, flow calibration Step 2: Introduce the heat transfer medium Thermal medium temperature: The above reaction locks the shell-side reaction reference temperature at 90–110℃, with temperature fluctuations ≤ ±1.5℃, and timely removal of the strongly exothermic chlorination process. Pipe flow rate: 0.5-2 m³ 3 / h Tube-side pressure: 0.1-1.0 MPa Heating rate ≤ 5℃ / min (slower is recommended for high viscosity systems) to prevent excessive thermal stress. Step 3: Introduce gas phase (stabilize airflow) Gas type: Selected according to reaction requirements; chlorine gas is selected for the above reaction. Inlet pressure: 0.1-0.5 MPa (gauge pressure) Gas temperature: ambient temperature ~ 200℃. Preheat if necessary to avoid condensation or thermal shock. Step 4: Liquid phase feeding and liquid film formation Liquid inlet flow rate: Calculated based on the shell-side cross-sectional area. If it is too small, the liquid film will be discontinuous; if it is too large, the liquid film will be too thick. Liquid film thickness: Depends on flow rate and viscosity, and can be observed or calculated through a viewing window. The inlet temperature is usually 0-5℃ lower than the temperature of the heat transfer medium. Preheating can be performed during inlet, but it should not exceed the reaction temperature. Step 5: Reaction process control and regulation Shell-side temperature: Thermal medium temperature ± 2℃, monitored by multi-point temperature measurement. Shell-side pressure: 0.01-0.5 MPa, to prevent gas phase short circuit. The gas-liquid ratio (volume ratio, standard conditions) is controlled by maintaining a chlorine gas velocity of 0.4–1.2 m / s and a gas-liquid molar ratio (chlorine relative to fatty acid excess coefficient) of 1.2–1.45 to achieve countercurrent gas-liquid contact and initiate the chlorination reaction. Liquid film renewal frequency: By adjusting the inlet flow rate, the residence time of the liquid film is ensured. Drainage rate: Matched to the inflow rate to maintain a stable liquid level. Step 6: Product discharge and gas emission Liquid products: continuously discharged from the drain port at the lowest end of the reactor. Unreacted gases: enter the exhaust gas treatment system (absorption, combustion, or recovery) through the top exhaust valve. Entrained droplet separation: If necessary, install a demister before the exhaust port. Sampling and Analysis: A sampling valve is installed at the drain outlet to periodically analyze the conversion rate and selectivity. Step 7: Parking and Cleaning Stop liquid feeding: First stop the liquid phase feed, then continue venting for 5-10 minutes to purge the shell side. Stop air intake: Close the intake valve and slowly release pressure. Cooling: Reduce the temperature of the heat transfer medium to a safe range (≤ 50℃). Emptying material: Completely empty the residual liquid in the shell and tube sides. Cleaning: Solvent or hot water can be circulated for cleaning. The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A liquid film reactor for gas-liquid reactions, characterized in that, It includes a reactor shell (1) and several reaction tubes (2) disposed inside the reactor shell (1) for carrying out chemical reactions. The reactor shell (1) and the reaction tube (2) are filled with reaction gas; during the reaction, a reaction liquid film is formed on the outer wall of the reaction tube (2); the inside of the reaction tube (2) is used for the flow of heat-conducting medium.

2. The liquid film reactor for gas-liquid reaction according to claim 1, characterized in that, The upper end of the reaction tube (2) is provided with an upper tube plate (2-1); the lower end of the reaction tube (2) is provided with a lower tube plate (2-2); a liquid distributor (10) is provided on the side of the reaction tube (2) near the upper tube plate (2-1); the liquid distributor (10) includes a support plate (11) and a liquid distribution pipe (12) that passes through the support plate (11); the reaction tube (2) passes through the liquid distribution pipe (12) and forms a gap with the liquid distribution pipe (12); the reaction liquid enters the gap between the liquid distribution pipe (12) and the reaction tube (2) from the upper end of the liquid distribution pipe (12) and moves downward along the outer wall of the reaction tube (2) by gravity.

3. The liquid film reactor for gas-liquid reaction according to claim 2, characterized in that, The upper tube sheet (2-1), lower tube sheet (2-2) and support plate (11) are all disposed on the inner wall of the reactor shell (1); a reaction liquid injection chamber (1-2) is formed between the upper tube sheet (2-1) and the support plate (11); a reaction chamber (1-1) is formed between the lower tube sheet (2-2) and the support plate (11).

4. The liquid film reactor for gas-liquid reaction according to claim 3, characterized in that, The wall of the reaction liquid injection chamber (1-2) is provided with an inlet (1-21) for injecting reaction liquid into the reaction liquid injection chamber (1-2); the lower tube plate (2-2) is provided with an outlet (2-21) for outputting the product after reaction in the reaction chamber (1-1).

5. The liquid film reactor for gas-liquid reaction according to claim 1, characterized in that, It also includes a heat transfer medium inlet (3) for inputting heat transfer medium into the reaction tube (2) and a heat transfer medium outlet (4) for outputting heat transfer medium from the reaction tube (2).

6. The liquid film reactor for gas-liquid reaction according to claim 3, characterized in that, The bottom of the reaction chamber (1-1) is provided with a gas inlet (1-11) for inputting reaction gas into the reaction chamber (1-1), and the top of the reaction chamber (1-1) is provided with a first exhaust port (1-12) for discharging gas from the reaction chamber (1-1).

7. The liquid film reactor for gas-liquid reaction according to claim 3, characterized in that, The reaction liquid injection chamber (1-2) is provided with a second exhaust port (1-22) for discharging the gas inside the reaction liquid injection chamber (1-2).

8. The liquid film reactor for gas-liquid reaction according to claim 3, characterized in that, The reaction tube (2) is a straight tube and / or a spiral tube.

9. The liquid film reactor for gas-liquid reaction according to claim 2, characterized in that, The gap between the reaction tube (2) and the liquid distribution tube (12) is 0.3-0.8 mm.

10. A method for a gas-liquid reaction, characterized in that, Use the liquid film reactor for gas-liquid reaction as described in any one of claims 1-9.

11. The gas-liquid reaction method according to claim 10, characterized in that, Includes the following steps: The reaction liquid enters the reaction liquid injection chamber (1-2) through the inlet (1-21); when the height of the reaction liquid in the reaction liquid injection chamber (1-2) is greater than the upper edge of the distribution pipe (12), the liquid begins to enter the gap between the distribution pipe (12) and the reaction pipe (2); under the action of gravity, the liquid flows down along the outer wall of the reaction pipe (2) and finally enters the reaction chamber (1-1), and the reaction chamber (1-1) contains the reaction gas injected from the gas inlet (1-11); the reaction takes place in the reaction chamber (1-1); the product after the reaction is output from the outlet (2-21); during the reaction, a heat-conducting medium is introduced into the reaction pipe (2).

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