Apparatus and method for low-temperature bubble absorption of a gas in a solvent liquid

Abstract

The application provides a device and method for absorbing gas by low-temperature bubble of solvent liquid phase. The device comprises a shell, a refrigerant heat exchange coil is arranged at the bottom of the shell, the refrigerant heat exchange coil is immersed in the absorption solvent in the shell during use, an air inlet pipe extends to the bottom of the solvent area below the heat exchange coil, a steady flow interception layer is arranged in the middle of the shell, an air outlet, a temperature sensor inlet, a refrigerant inlet and outlet and a solvent extraction pipe are arranged at the top of the shell. The method is to fill mixed absorption solvent into the shell to immerse the refrigerant heat exchange coil, to pass the refrigerant into the refrigerant heat exchange coil to precool the solvent to a set temperature in the range of-20 DEG C to-100 DEG C and keep stable, to pass the gas containing target components, to regulate the air inlet pressure and the negative pressure of the air outlet to drive the gas to bubble up from the bottom of the solvent, to exchange gas-liquid mass transfer with the solvent, to complete the dissolution absorption and condensation capture synchronously, to discharge the tail gas from the top of the shell, and to recover the target gas components through post-treatment of the saturated solvent. The application keeps the stable mass transfer performance of the solvent in the temperature range of-20 DEG C to-100 DEG C through the immersed liquid phase heat exchange, and realizes the efficient dissolution absorption and condensation capture of the target gas components.

Description

Technical Field

[0001] This application relates to the field of gas absorption and separation technology, specifically to a device and method for low-temperature bubbling absorption of gas in a solvent liquid phase. Background Technology

[0002] In biological, chemical, and pharmaceutical production processes, various gaseous components are typically generated. Some of these are target products with recovery value, while others are hazardous components requiring purification. Efficient absorption and separation of these gases is a crucial step in industrial production. Currently, commonly used industrial gas absorption processes include headspace solvent bubbling, spray tower absorption, and condensation.

[0003] Both headspace solvent bubbling and spray tower absorption methods rely on the polar compatibility between the solvent and the gas phase components to achieve absorption and separation. The process is stable and the equipment structure is simple. However, the absorption effect is limited by both the solvent saturation capacity and the gas-liquid exchange efficiency. Under normal temperature conditions, the driving force for the absorption of low-boiling-point components is insufficient, and the overall recovery rate is low. If the system temperature is lowered to enhance the absorption effect, the viscosity of conventional polar solvents will rise sharply, and even solidification may occur. This will lead to the obstruction of bubbling mass transfer and the decrease in gas-liquid contact efficiency, making it unsuitable for continuous operation under low-temperature conditions.

[0004] The condensation method relies on a cold environment to reduce the saturated vapor pressure of gaseous components, thereby achieving component condensation and capture. It has excellent recovery effect on high-boiling-point components, but it cannot be effectively adapted to gaseous systems containing water vapor. Especially for the high-temperature and high-humidity reaction gases after the reaction, water vapor is prone to rapid frost and scale formation on the heat exchange surface of the refrigerant, resulting in a continuous decline in heat exchange efficiency. Frequent shutdowns are required for defrosting operations, making it impossible to achieve long-term continuous operation. At the same time, this process has limited condensation and capture efficiency for low-boiling-point light components, making it difficult to achieve efficient recovery of all components.

[0005] In summary, existing technologies cannot simultaneously achieve efficient gas-liquid mass transfer and stable condensation and capture of gases with high humidity and low boiling point components under low-temperature conditions.

[0006] Application content This application provides a device and method for absorbing gases by low-temperature bubbling in a solvent liquid phase, aiming to solve the technical problem that the prior art cannot simultaneously achieve efficient gas-liquid mass transfer and stable condensation and capture effects under low-temperature conditions for gases with high temperature, high humidity, and low-boiling-point components.

[0007] The first aspect of this application provides a device for absorbing gas by low-temperature bubbling in a solvent liquid phase, comprising a housing, a refrigerant heat exchange coil fixed at the bottom of the housing and immersed in an absorption solvent within the housing; an inlet pipe extending to the bottom of the solvent region below the refrigerant heat exchange coil; a flow stabilizing and retaining layer in the middle of the housing; and an exhaust port and a temperature sensor inlet at the top of the housing, and the top of the housing also has a refrigerant inlet and outlet, a solvent extraction pipe, and an exhaust port.

[0008] Preferably, the refrigerant heat exchange coil is a spiral coil.

[0009] Preferably, the outer side of the shell is covered with a vacuum insulation layer.

[0010] Preferably, the current stabilizing and retaining layer is filled with glass beads.

[0011] Preferably, at least two devices are connected in parallel, each device is independently supplied with the gas to be treated containing the target component, and the exhaust gas is discharged.

[0012] The second aspect of this application provides a method for low-temperature bubbling absorption of gas in a solvent liquid phase. A mixed absorbent solvent is introduced into a housing until the liquid surface submerges a refrigerant heat exchange coil. Refrigerant is then introduced into the refrigerant heat exchange coil to pre-cool the solvent to a set temperature within the range of -20°C to -100°C and maintain this temperature stably. A gas to be treated containing the target component is introduced, and the inlet pressure and the negative pressure at the extraction end are adjusted so that the gas phase pressure at the inlet end is greater than the sum of the gas phase pressure at the extraction end and the static pressure of the solvent liquid column at the inlet outlet. This drives the gas to bubble upwards from the bottom of the solvent, undergoing gas-liquid mass transfer with the solvent, simultaneously completing solvent dissolution and absorption as well as condensation and capture. The exhaust gas is discharged from the top of the housing. When the solvent absorption saturation reaches a preset value, saturated solvent is discharged. The saturated solvent is then post-treated to recover the target gas component.

[0013] Preferably, the gas that is not completely absorbed after gas-liquid mass exchange with the solvent rises into the steady flow trapping layer, where it undergoes secondary gas-liquid mass exchange and low-temperature condensation and capture with the solvent film formed on the packing surface, thus completing the secondary absorption.

[0014] Preferably, the mixed absorption solvent is composed of ethanol and ethyl acetate in a mass ratio of (1.2~2.5):1. The mixed absorption solvent maintains stable viscosity and gas-liquid mass transfer absorption capacity within a temperature range of -20℃ to -100℃. The solvent temperature is pre-cooled to -40℃ and remains stable.

[0015] Preferably, propylene glycol is added to the mixed absorbent solvent, and the mass percentage of propylene glycol is 15% to 20%.

[0016] Preferably, a device for absorbing gases by low-temperature bubbling of solvent liquid phase is used, wherein the temperature of the mixed absorption solvent is pre-cooled to a set temperature within the range of -50°C to -80°C and kept stable.

[0017] Preferably, the post-processing includes dehydration, filtration and evaporation steps. The dehydration step uses 3A molecular sieve to absorb water in the solvent to obtain a solvent containing only the target gas component. Then, the filtration and evaporation steps are used to obtain a mixture containing the target gas and auxiliary solvents of ethanol, ethyl acetate and PG.

[0018] The beneficial effects achievable by this application include: 1. The solvent maintains good fluidity and mass transfer performance under low-temperature conditions, avoiding the problem of a sharp increase in viscosity and solidification of conventional solvents at low temperatures; 2. Simultaneous dissolution absorption and low-temperature condensation capture significantly improve the recovery efficiency of low-boiling-point light components; 3. It can be adapted to high-temperature and high-humidity gas-phase systems, avoiding the frosting and scaling problems of traditional condensation methods, and can achieve long-term continuous operation; 4. The equipment has a simple structure and stable operation, and the processing capacity and absorption efficiency can be further improved by connecting multiple units in parallel.

[0019] It should be understood that the description in this section is not intended to identify key or important features of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0020] The accompanying drawings exemplify embodiments and form part of the specification, working together with the textual description to explain exemplary implementations of the embodiments. The drawings shown are for illustrative purposes only and do not limit the scope of the claims. Throughout the drawings, the same reference numerals refer to similar but not necessarily identical elements.

[0021] Figure 1 This is a schematic diagram of the structure of a device for low-temperature bubbling absorption of gas in a solvent liquid phase according to this application; Figure 2 This is a schematic diagram of the top structure of a device for low-temperature bubbling and gas absorption in a solvent liquid phase according to this application; Detailed Implementation To make the purpose, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0022] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0023] In the description of the embodiments of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. The term "multiple" means two or more, unless otherwise explicitly specified. The term "comprising" indicates the presence of the described feature, whole, step, operation, element, and / or component, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or sets thereof. The term "and / or" describes the relationship between related objects, indicating that three relationships may exist. For example, A and / or B may include three cases: A existing alone, A and B existing simultaneously, and B existing alone. The character " / " generally indicates that the related objects before and after are in an "or" relationship.

[0024] Unless otherwise defined, all technical terms used in the embodiments of this application have the same meaning as commonly understood by one of ordinary skill in the art; the terms used in the embodiments of this application are for the purpose of describing specific embodiments only and are not intended to limit this application; the terms "comprising" and "having" and any variations thereof in the specification, claims and foregoing description of the drawings of this application are intended to cover non-exclusive inclusion.

[0025] Furthermore, terms such as "exemplary," "for example," and "optional" are used to indicate illustrative purposes. Any technical solution described by the above terms in the embodiments of this application should not be construed as being more preferred or advantageous than other technical solutions. Specifically, these terms are intended to present the relevant technical concepts in terms of specific implementation methods.

[0026] like Figure 1-2As shown, the solvent-liquid phase low-temperature bubbling gas absorption device of this application includes a housing 1, with a refrigerant heat exchange coil 2 fixed at the bottom of the housing 1, the refrigerant heat exchange coil 2 being immersed in the absorption solvent within the housing 1; an inlet pipe 3 extending to the bottom of the solvent area below the refrigerant heat exchange coil 2; a flow stabilizing and retaining layer 4 in the middle of the housing 1; an exhaust port 5 and a temperature sensor inlet 6 at the top of the housing 1; and refrigerant inlets and outlets 7, a solvent extraction pipe 11, and an exhaust port 10 around the top periphery of the housing 1. A vacuum insulation layer 8 can be applied to the outside of the housing 1. Within a temperature range of -20℃ to -100℃, the ethanol-ethyl acetate-based compound solvent used in this application can maintain suitable viscosity and fluidity, ensuring sufficient gas-liquid mass transfer. Example 1 1. Fill the shell 1 with a mixed absorbent solvent of ethanol and ethyl acetate in a mass ratio of 3:2 until the liquid surface submerges the refrigerant heat exchange coil 2. Introduce refrigerant into the refrigerant heat exchange coil 2; the refrigerant is selected from one or more of liquid nitrogen, Freon, and ethylene glycol coolant, pre-cooling the solvent to -40°C and maintaining a stable temperature. Introduce the gas to be treated containing the target component, adjusting the inlet pressure and the top suction negative pressure to ensure that the inlet pressure is greater than the sum of the suction pressure and the corresponding liquid column static pressure, controlling the inlet gas flow rate and the gas-liquid contact residence time. Gas rises from the bottom of the solvent through bubbling, making full contact with the solvent and simultaneously completing gas-liquid exchange, dissolution, and low-temperature condensation and capture. Gas that is not fully absorbed carries solvent droplets and rises into the stabilizing and retaining layer 4. The glass bulb surface is wetted by the solvent, forming a liquid film. The tortuous flow channel formed by the stabilizing and retaining layer 4 buffers the rising gas flow, preventing rapid gas-liquid separation. As the rising gas penetrates the stabilizing and retaining layer 4, it again undergoes gas-liquid contact exchange and deep capture with the liquid film, completing the secondary absorption. The exhaust gas is discharged from the top of the shell. When the solvent absorption saturation reaches a preset value, the saturated solvent is discharged. After water vapor is removed by a 3A molecular sieve, the saturated solvent is sequentially filtered and evaporated to obtain a mixture containing the target gas and auxiliary solvents ethanol, ethyl acetate, and PG. Example 2 The device employs an outer vacuum insulation layer 10. A mixed absorbent solvent, composed of ethanol, ethyl acetate, and propylene glycol in a mass ratio of 6:4:2, is introduced into the shell 1, with propylene glycol comprising 16.7% of the solvent by mass. At this ratio, the solvent maintains good flow characteristics even at -60°C. A refrigerant, selected from one or more of liquid nitrogen, Freon, and ethylene glycol coolant, is introduced into the refrigerant heat exchange coil 2 to pre-cool the solvent to -70°C and maintain its stability. A gas to be treated containing the target component is introduced, and the inlet pressure and extraction negative pressure are adjusted to control the inlet gas flow rate and gas-liquid contact residence time. The remaining steps are the same as in Example 1. Example 3 The device employs a vacuum insulation layer 10 and a liquid-phase condenser coil 11. A mixed absorbent solvent, composed of ethanol, ethyl acetate, and propylene glycol in a mass ratio of 17:8:5, is introduced into the shell 1, with propylene glycol accounting for 16.7% of the mass. At this ratio, the solvent maintains good flow characteristics even at -60°C. A refrigerant, selected from one or more of liquid nitrogen, Freon, and ethylene glycol coolant, is introduced into the refrigerant heat exchange coil 2 to pre-cool the bottom solvent to -50°C and maintain its stability. Simultaneously, the temperature of the liquid-phase condenser coil 11 is pre-cooled to -90°C. Maintaining a suitable temperature for the bottom solvent ensures bubble stability, solvent flowability, and the formation of the liquid film in the flow-stabilizing trap layer 4. The liquid-phase condenser coil 11 performs deep condensation and capture of the rising gas phase, further improving the recovery rate of low-boiling-point components. A gas to be treated containing the target components is introduced, and the inlet pressure and suction negative pressure are adjusted to control the inlet gas flow rate and gas-liquid contact residence time. The remaining steps are the same as in Example 1.

[0027] The above embodiments are only used to illustrate the present application and are not intended to limit it. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included within the protection scope of the present application.

Claims

1. A device for absorbing gases by low-temperature bubbling in a solvent liquid phase, characterized in that, The device includes a housing, a refrigerant heat exchange coil fixed at the bottom of the housing and immersed in an absorbent solvent inside the housing; an air inlet pipe extending to the bottom of the solvent area below the refrigerant heat exchange coil; a flow stabilizing and retaining layer in the middle of the housing; and an air extraction outlet and a temperature sensor inlet at the top of the housing. The top of the housing also has a refrigerant inlet / outlet, a solvent extraction pipe, and an air extraction port.

2. The apparatus for low-temperature bubbling absorption of gas in a solvent liquid phase according to claim 1, characterized in that, The refrigerant heat exchange coil is a spiral coil.

3. The apparatus for low-temperature bubbling absorption of gas in a solvent liquid phase according to claim 2, characterized in that, The outer side of the shell is covered with a vacuum insulation layer.

4. The apparatus for low-temperature bubbling absorption of gas in a solvent liquid phase according to claim 3, characterized in that, The current stabilization and interception layer is filled with glass spheres. The filling height of the current stabilization and interception layer is 0.3 to 1.0 times the diameter of the shell, and the diameter of the glass spheres is 5 to 15 mm.

5. The device according to claim 1, characterized in that, At least two devices are connected in parallel, each device is independently supplied with the gas to be treated containing the target component, and the exhaust gas is discharged.

6. A method for absorbing gas by low-temperature bubbling in a solvent liquid phase, characterized in that, The mixed absorbent solvent is filled into the shell until the liquid surface submerges the refrigerant heat exchange coil. Refrigerant is then introduced into the refrigerant heat exchange coil to pre-cool the solvent to a set temperature within the range of -20℃ to -100℃ and maintain it stable. The gas to be treated containing the target component is then introduced. The inlet gas pressure and the negative pressure at the extraction end are adjusted so that the gas phase pressure at the inlet end is greater than the sum of the gas phase pressure at the extraction end and the static pressure of the solvent liquid column. This drives the gas to bubble and rise from the bottom of the solvent, where it undergoes gas-liquid mass transfer exchange with the solvent, simultaneously completing solvent dissolution and absorption as well as low-temperature condensation and capture. The exhaust gas is discharged from the top of the shell. When the solvent absorption saturation reaches a preset value, the saturated solvent is discharged. The saturated solvent is then post-treated to recover the target gas component.

7. The method for low-temperature bubbling absorption of gas in a solvent liquid phase according to claim 6, characterized in that, After gas-liquid mass exchange with the solvent, the gas that is not completely absorbed rises into the steady flow trapping layer, where it undergoes secondary gas-liquid mass exchange and low-temperature condensation and capture with the solvent film formed on the surface of the glass ball packing, thus completing the secondary absorption.

8. The method for low-temperature bubbling absorption of gas in a solvent liquid phase according to claim 7, characterized in that, The mixed absorption solvent is composed of ethanol and ethyl acetate in a mass ratio of (1.2~2.5):

1. The mixed absorption solvent maintains good fluidity and stable viscosity and gas-liquid mass transfer absorption capacity within a temperature range of -20℃ to -100℃. The solvent temperature is pre-cooled to -40℃ and remains stable.

9. The method for low-temperature bubbling absorption of gas in a solvent liquid phase according to claim 8, characterized in that, The mixed absorption solvent contains propylene glycol, with a mass ratio of 15% to 20%.

10. The method for low-temperature bubbling absorption of gas in a solvent liquid phase according to claim 9, characterized in that, The device uses a solvent liquid phase low-temperature bubbling absorption gas with a vacuum insulation layer covering the outer shell. The temperature of the mixed absorption solvent is pre-cooled to a set temperature within the range of -50°C to -80°C and kept stable.

11. The method for low-temperature bubbling absorption of gas in a solvent liquid phase according to claim 7, characterized in that, The post-processing includes dehydration, filtration and evaporation steps. The dehydration step uses 3A molecular sieve to absorb water in the solvent to obtain a solvent containing only the target gas component. Then, the filtration and evaporation steps are used to obtain a mixture containing the target gas and auxiliary solvents of ethanol, ethyl acetate and PG.

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