Solid-liquid two-phase absorbent and its preparation method and application

Abstract

The present invention discloses a solid-liquid two-phase absorbent, its preparation method, and application. The solid-liquid two-phase absorbent comprises a piperidine derivative, a piperazine derivative, and an organic solvent. The piperidine derivative contains a primary amine group, and the piperazine derivative contains an alkyl group. The present invention can reduce the risk of pipeline blockage during use of the solid-liquid two-phase absorbent and improve its application effect.

Description

Technical Field

[0001] The present invention relates to the field of gas capture, and in particular to a solid-liquid two-phase absorbent and a preparation method and application thereof. Background Art

[0002] Solid-liquid two-phase absorbents are an emerging class of carbon dioxide absorbents. After absorbing carbon dioxide, they spontaneously separate into a liquid phase containing a small amount of CO2 and a solid phase containing a large amount of CO2. During the absorbent's recycling process, the solid phase only needs to be desorbed to remove the CO2 before it can be recycled again. Organic amine-nonaqueous solvent mixtures, one type of solid-liquid two-phase absorbent, offer the advantages of low corrosive potential and low cost. However, these absorbents are prone to precipitating a viscous solid phase during carbon dioxide absorption, causing pipeline blockages and severely restricting their industrial application. Summary of the Invention

[0003] In order to reduce the risk of pipeline blockage during the use of a solid-liquid two-phase absorbent, embodiments of the present invention disclose a solid-liquid two-phase absorbent, a preparation method, and an application thereof.

[0004] In a first aspect, an embodiment of the present invention provides a solid-liquid two-phase absorbent.

[0005] A solid-liquid two-phase absorbent comprises a piperidine derivative, a piperazine derivative and an organic solvent. The piperidine derivative contains a primary amine group, and the piperazine derivative contains an alkyl group.

[0006] As an optional embodiment, in an embodiment of the present invention, the molar ratio of the piperidine derivative to the piperazine derivative is (9:1) to (3:2).

[0007] As an optional embodiment, in an embodiment of the present invention, the total concentration of the piperidine derivative and the piperazine derivative is 0.5 mol / kg to 3 mol / kg.

[0008] As an optional implementation, in an embodiment of the present invention, the total number of carbon atoms in the alkyl group is less than or equal to 3.

[0009] As an optional embodiment, in an embodiment of the present invention, the piperazine derivative includes one or more combinations of 2-methylpiperazine, 2,6-dimethylpiperazine, N-methylpiperazine, N-ethylpiperazine, and N-isopropylpiperazine.

[0010] As an optional embodiment, in an embodiment of the present invention, the piperidine derivative includes one or more combinations of 4-aminopiperidine, 4-amino-1-methylpiperidine, 2-amino-1-methylpiperidine, 3-aminopiperidine, 2,5-diaminopiperidine or 4-amino-1-piperidine propanol.

[0011] As an optional embodiment, in an embodiment of the present invention, the organic solvent has a viscosity of 0.8 mPa·s to 2.5 mPa·s and includes one or more of N-methylpyrrolidone, dimethylacetamide, dimethyl sulfoxide or N-ethylpyrrolidone.

[0012] In a second aspect, an embodiment of the present invention provides a method for preparing a solid-liquid two-phase absorbent.

[0013] A method for preparing the solid-liquid two-phase absorbent as described in the first aspect comprises the following steps: placing the piperidine derivative and the piperazine derivative in the organic solvent and mixing and stirring to obtain the solid-liquid two-phase absorbent.

[0014] In a third aspect, an embodiment of the present invention provides an application of a solid-liquid two-phase absorbent.

[0015] An application of a solid-liquid two-phase absorbent, such as the solid-liquid two-phase absorbent described in the first aspect, for capturing carbon dioxide, comprises the following steps:

[0016] At 30° C. to 60° C., a gas containing carbon dioxide is introduced into the solid-liquid two-phase absorbent; after absorbing the gas containing carbon dioxide, the solid-liquid two-phase absorbent spontaneously separates into layers, with the upper layer being the organic phase and the lower layer being the solid phase.

[0017] As an optional embodiment, in an embodiment of the present invention, the carbon dioxide is enriched in the solid phase, the enrichment of the carbon dioxide in the solid phase is 85% to 95%, and the particle size of the solid phase is 1 μm to 100 μm.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] A kind of solid-liquid two-phase absorbent provided by an embodiment of the present invention, a piperazine derivative containing a specific group is added to the solid-liquid two-phase absorbent to combine with a piperidine derivative, the solid-liquid two-phase absorbent and carbon dioxide reaction can not only form a solid product, spontaneously realize solid-liquid two-phase separation, but also can make the solid product appear powdery, and the solid product forms a low-viscosity suspension in an organic solvent, thereby being relatively evenly dispersed in the reaction conduit, and can better reduce the risk of spontaneous aggregation and formation of blockage. The solid product of the piperidine derivative is easy to form a thick large-volume precipitation problem. In addition, compared with the thick large-volume precipitation produced by using piperidine derivatives alone, the solid phase volume of the powdered product produced by the present invention is smaller, and carbon dioxide enrichment is high, which is beneficial to reduce regeneration energy consumption, thereby better reducing the cost of capturing carbon dioxide. Specifically, the solid product formed by the reaction of piperidine derivatives with carbon dioxide is a zwitterionic state, with the characteristics of easy self-aggregation. In the state without the addition of piperazine derivatives, it is easy to aggregate to form a thick large-volume precipitation. After adding a piperazine derivative containing an alkyl group, the piperazine derivative reacts with carbon dioxide. The resulting ionic product, through hydrogen bonding with the zwitterionic product of the piperidine derivative, inhibits the aggregation of the zwitterionic product and combines with the zwitterionic product to form a powdery product. Thus, after adding the piperazine derivative containing an alkyl group, the piperazine derivative not only reacts with carbon dioxide, enhancing its absorption, but also the resulting product can combine with the solid product, altering its properties and making it less susceptible to spontaneous aggregation. Furthermore, because the piperazine derivative contains an alkyl group, the alkyl group provides a moderate steric hindrance, promoting the transformation of the solid product from a viscous state to a powdery state. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 Schematic diagram of solid phase photographs of Comparative Example 1 and Example 1 in the embodiments of the present invention. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0023] In the present invention, terms such as "upper," "lower," "left," "right," "front," "back," "top," "bottom," "inner," "outer," "center," "vertical," "horizontal," "transverse," and "longitudinal" indicate positions or locations based on the positions or locations shown in the accompanying drawings. These terms are primarily intended to better describe the present invention and its embodiments and are not intended to limit the devices, elements, or components indicated to having a specific orientation, or to being constructed or operated in a specific orientation.

[0024] Furthermore, some of the above terms may be used to express other meanings besides indicating a position or location. For example, the term "on" may also be used to indicate a dependency or connection in certain circumstances. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0025] Furthermore, the terms "installed," "disposed," "provided with," "connected," and "connected" should be interpreted broadly. For example, they can refer to fixed connections, removable connections, or integral structures; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; or internal communication between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0026] Furthermore, the terms "first," "second," and the like are primarily used to distinguish different devices, elements, or components (which may or may not be the same in type and configuration) and are not intended to indicate or imply the relative importance or quantity of the devices, elements, or components indicated. Unless otherwise specified, "plurality" means two or more.

[0027] Among solid-liquid two-phase absorbents, piperidine derivatives containing primary amine groups can produce solid products after absorbing carbon dioxide, achieving solid-liquid two-phase stratification and showing better separation advantages. However, when only the piperidine derivative is added as an absorbent, the solid product formed after the piperidine derivative reacts with carbon dioxide has a viscous characteristic, and the solid product is a zwitterionic product that will spontaneously aggregate, thereby easily forming a clay-like large-volume precipitate.

[0028] In industrial applications, solid-liquid two-phase absorbents are typically placed in pipelines to absorb carbon dioxide gas flowing into the pipelines. However, these solid products tend to form viscous, bulky precipitates, which can easily clog the pipelines and disrupt the normal operation of the carbon dioxide adsorption equipment.

[0029] In order to reduce the risk of pipeline blockage and improve the application effect of solid-liquid two-phase absorbent, the present invention provides a solid-liquid two-phase absorbent and a preparation method and application thereof.

[0030] The technical solution of the present invention will be further described below in conjunction with embodiments and drawings.

[0031] In a first aspect, an embodiment of the present invention provides a solid-liquid two-phase absorbent.

[0032] A solid-liquid two-phase absorbent comprising a piperidine derivative, a piperazine derivative and an organic solvent;

[0033] Among them, piperidine derivatives contain primary amine groups, and piperazine derivatives contain alkyl groups.

[0034] The present invention combines a piperazine derivative containing a specific group with a piperidine derivative. The solid-liquid two-phase absorbent reacts with carbon dioxide to form a solid product and spontaneously achieve solid-liquid two-phase separation. The solid product can also be powdered, and the solid product forms a low-viscosity suspension in an organic solvent, thereby being relatively uniformly dispersed in a reaction pipe. This can better reduce the risk of spontaneous aggregation and blockage, and can better solve the problem that the solid product of the piperidine derivative easily forms a viscous, large-volume precipitate.

[0035] In addition, compared with the viscous and large-volume precipitate produced by using piperidine derivatives alone, the powdered product produced by the present invention has a smaller solid phase volume and a high carbon dioxide enrichment, which is beneficial for reducing regeneration energy consumption, thereby better reducing the cost of capturing carbon dioxide.

[0036] Specifically, the reaction formula of the piperidine derivative and carbon dioxide is as follows:

[0037]

[0038] (zwitterionic product)

[0039] The solid product formed by the reaction of the piperidine derivative with carbon dioxide is in a zwitterionic state and has the characteristic of easily self-aggregating. In the absence of the piperazine derivative, it easily aggregates to form a viscous, large-volume precipitate. For example, the chemical formula of the viscous, large-volume precipitate A can be as follows:

[0040] (A),

[0041] The reaction formula for generating the viscous bulk precipitate A is shown below:

[0042]

[0043] (viscous large volume precipitate A)

[0044] After adding a piperazine derivative containing an alkyl group, the piperazine derivative reacts with carbon dioxide. The reaction formula is as follows:

[0045]

[0046] The ionic product formed by the reaction of the piperazine derivative containing an alkyl group and the zwitterionic product of the piperidine derivative hinders the aggregation of the zwitterionic product through hydrogen bonding, and combines with the zwitterionic product to form a powdered product. For example, the chemical formula of the powdered product B can be as follows:

[0047] (B)

[0048] The reaction formula for generating the powdered product B is shown below:

[0049]

[0050] (Powdered product B)

[0051] As can be seen, after adding the piperazine derivative with an alkyl group, the piperazine derivative not only reacts with carbon dioxide, enhancing its absorption, but also the resulting product can combine with the solid product, changing its properties and making it less likely to spontaneously aggregate. Furthermore, because the piperazine derivative contains an alkyl group, the alkyl group can provide a moderate steric hindrance, promoting the transformation of the solid product from a viscous state to a powdery state.

[0052] After the adsorption is completed, the powdered solid product is isolated from the liquid phase and transferred to a desorption tower for analytical treatment to remove carbon dioxide and restore the powdered solid product to a liquid phase.

[0053] It should be noted that the piperidine derivative structures shown above are merely examples of piperidine derivatives containing primary amine groups, and are intended to schematically illustrate the basic characteristics of the piperidine derivatives. However, in actual applications, the selection of piperidine derivatives is not limited to these example structures. The piperidine ring may have a variety of substituent groups, including but not limited to alkyl, alkenyl, alkynyl, aryl, alkoxy, aryloxy, alkylthio, arylthio, halogen, hydroxyl, cyano, nitro, carboxyl, ester, amide, and the like. In addition, the primary amine group may also be located at different positions on the piperidine ring, such as the 2-position, the 3-position, and the like. Similarly, the piperazine derivatives shown above are merely examples of piperazine derivatives, and in actual applications, the selection of piperazine derivatives is not limited to these example structures.

[0054] In some embodiments, the molar ratio of the piperidine derivative to the piperazine derivative is (9:1) to (3:2).

[0055] By adjusting the dosage ratio of the two, the morphology of the solid product can be further controlled, so that the solid product can be more effectively transformed from a viscous state to a powdery state, thereby reducing the risk of blockage. At the same time, more active sites can be provided, thereby increasing the absorbent's absorption capacity for carbon dioxide, thereby increasing the enrichment of carbon dioxide and reducing regeneration energy consumption.

[0056] When the molar ratio of piperidine derivatives to piperazine derivatives is too low, the amount of piperazine derivatives is relatively low, and the piperazine derivative's regulatory effect on the reaction products is relatively weak. This may lead to slower solid-phase product formation or less than ideal solid-phase product morphology, hindering the reduction of clogging risk. When the molar ratio of piperidine derivatives to piperazine derivatives is too high, the amount of piperidine derivatives is relatively low, potentially reducing the absorbent's carbon dioxide absorption capacity. Therefore, by rationally adjusting the molar ratio, it is possible to optimize solid-phase product formation and separation performance while maintaining absorption capacity, further reducing clogging risk and regeneration energy consumption.

[0057] Illustratively, the molar ratio of the piperidine derivative to the piperazine derivative may be (9:1), (8:1), (7:1), (4:1), (5:1), (5:2), (2:1) or (3:2).

[0058] In some embodiments, the total concentration of the piperidine derivative and the piperazine derivative is 0.5 mol / kg to 3 mol / kg.

[0059] When the concentration of piperidine derivatives and piperazine derivatives is within this range, the collection effect of carbon dioxide is better, which can not only ensure the effective absorption of carbon dioxide by the absorbent and form a solid product with a suitable volume ratio, but also avoid problems such as low absorption efficiency or increased cost due to excessively high or low concentrations.

[0060] It should be noted that the concentration unit of the piperidine derivative is mass molar concentration, that is, mole per kilogram (mol / kg), which represents the number of moles of the piperidine derivative contained in 1 kg of organic solvent.

[0061] Illustratively, the concentration of the piperidine derivative may be 0.5 mol / kg, 1 mol / kg, 1.5 mol / kg, or 2 mol / kg.

[0062] In some embodiments, the total number of carbon atoms in the alkyl group is 3 or less.

[0063] By regulating the total number of carbon atoms in the alkyl group to be less than or equal to 3, on the one hand, a more suitable steric hindrance effect can be constructed, which is conducive to the transformation of the product into a powdery state; at the same time, it also makes the ionic product formed by the reaction of the piperazine derivative and carbon dioxide more soluble in organic solvents, so as to facilitate rapid combination with the zwitterionic product formed by the reaction of the piperazine derivative and carbon dioxide, thereby promoting the formation and stability of the powdery product.

[0064] In some embodiments, the piperazine derivative includes one or more of 2-methylpiperazine, 2,6-dimethylpiperazine, N-methylpiperazine, N-ethylpiperazine, or N-isopropylpiperazine.

[0065] By selecting one or more combinations of alkyl groups such as methyl, ethyl or isopropyl, and placing these alkyl groups at different positions on the piperazine ring, the piperazine derivative reacts with carbon dioxide to form an ionic product with suitable steric hindrance, thereby making it easier to obtain a solid-phase product that is easy to separate.

[0066] In some embodiments, the piperidine derivative includes one or more of 4-aminopiperidine, 4-amino-1-methylpiperidine, or 4-amino-1-piperidinepropanol.

[0067] Both 4-aminopiperidine and 4-amino-1-piperidine propanol have high reaction activity with carbon dioxide and can quickly form corresponding ion products. In addition, the reaction products of 4-aminopiperidine or 4-amino-1-piperidine propanol and carbon dioxide have better water solubility, which is conducive to the formation of powdered products and helps to further reduce the risk of clogging.

[0068] In some embodiments, the viscosity of the organic solvent is 0.8 mPa·s to 2.5 mPa·s, and the organic solvent includes one or more of N-methylpyrrolidone, N,N-dimethylacetamide, dimethyl sulfoxide, or N-ethylpyrrolidone.

[0069] The viscosity of the organic solvent is low, the diffusion coefficient of carbon dioxide and other absorption components in the liquid absorbent is higher, and the mass transfer resistance at the gas-liquid interface is significantly reduced, thereby accelerating the absorption rate of carbon dioxide and other absorption components.

[0070] N-methylpyrrolidone, dimethylacetamide, dimethyl sulfoxide or N-ethylpyrrolidone all have moderate viscosity and polarity, which is beneficial to improving the absorption rate of carbon dioxide and other absorption components.

[0071] In a second aspect, an embodiment of the present invention provides a method for preparing a solid-liquid two-phase absorbent.

[0072] A method for preparing a solid-liquid two-phase absorbent, as mentioned in the first aspect, comprises the following steps: placing a piperidine derivative and a piperazine derivative in an organic solution and mixing and stirring to obtain a solid-liquid two-phase absorbent.

[0073] By mixing and stirring piperidine and piperazine derivatives in an organic solvent, the components can be thoroughly mixed to form a stable solid-liquid two-phase absorbent. During the stirring process, the molecules of the piperidine and piperazine derivatives diffuse into each other in the organic solvent, forming a uniform mixture. This mixing method is simple and easy to implement, does not require complex equipment and process conditions, and is conducive to large-scale production and application.

[0074] In a third aspect, an embodiment of the present invention provides an application of a solid-liquid two-phase absorbent.

[0075] An application of a solid-liquid two-phase absorbent, such as the solid-liquid two-phase absorbent mentioned in the first aspect, for capturing carbon dioxide, comprises the following steps:

[0076] At 30°C to 60°C, gas containing carbon dioxide is introduced into the solid-liquid two-phase absorbent;

[0077] After absorbing the gas containing carbon dioxide, the solid-liquid two-phase absorbent spontaneously separates into layers, with the upper layer being the organic phase and the lower layer being the solid phase.

[0078] At temperatures between 30°C and 60°C, the solid-liquid two-phase absorbent exhibits excellent fluidity and reactivity. When a gas containing carbon dioxide is introduced into the solid-liquid two-phase absorbent, the piperidine derivative containing a primary amine group reacts with the carbon dioxide to form a zwitterionic product. Simultaneously, the piperazine derivative containing an alkyl group reacts with the carbon dioxide to form an ionic product. This ionic product and the zwitterionic product can combine to form a powdered solid product. This solid product can be dispersed in an organic solvent to form a suspension, which helps reduce the risk of pipeline blockage.

[0079] In some implementations, the carbon dioxide is enriched in the solid phase, the enrichment of the carbon dioxide in the solid phase is 85% to 95%, and the particle size of the solid phase is 1 μm to 100 μm.

[0080] As carbon dioxide reacts chemically with the solid-liquid two-phase absorbent, the resulting product is enriched in the solid phase. The solid phase of the present invention has a higher enrichment, meaning that the solid phase product contains more carbon dioxide, which is beneficial for improving the absorption efficiency of the absorbent and reducing regeneration energy consumption.

[0081] A moderate solid particle size (e.g., 1 μm to 100 μm) facilitates the dispersion and separation of solid products, reducing the risk of pipeline clogging. Smaller solid particle sizes increase the surface area of the solid product, facilitating separation from the organic phase. Therefore, by controlling the solid particle size within an appropriate range, the separation and regeneration performance of the solid product can be optimized while maintaining absorption efficiency, further reducing the risk of clogging and regeneration energy consumption.

[0082] The technical solution of the present invention will be further described below in conjunction with more specific embodiments.

[0083] Example 1

[0084] An embodiment of the present invention provides a solid-liquid two-phase absorbent, which is composed of 4-amino-1-methylpiperidine, 2-methylpiperazine and N-methylpyrrolidone, wherein the molar ratio of 4-amino-1-methylpiperidine to 2-methylpiperazine is 5:1, and the concentration of the solute is 0.5 mol / kg.

[0085] The preparation method of the solid-liquid two-phase absorbent is as follows: 4-amino-1-methylpiperidine and 2-methylpiperazine are placed in N-methylpyrrolidone, mixed and stirred to obtain the solid-liquid two-phase absorbent.

[0086] Example 2

[0087] An embodiment of the present invention provides a solid-liquid two-phase absorbent, which is composed of 4-amino-1-methylpiperidine, 2,6-dimethylpiperazine and N-methylpyrrolidone, wherein the molar ratio of 4-amino-1-methylpiperidine to 2,6-dimethylpiperazine is 5:1, and the concentration of the solute is 0.5 mol / kg.

[0088] The preparation method of the solid-liquid two-phase absorbent is as follows: 4-amino-1-methylpiperidine, 2,6-dimethylpiperazine and N-methylpyrrolidone are placed and mixed and stirred to obtain the solid-liquid two-phase absorbent.

[0089] Example 3

[0090] An embodiment of the present invention provides a solid-liquid two-phase absorbent, which is composed of 4-amino-1-methylpiperidine, N-ethylpiperazine and N-methylpyrrolidone, wherein the molar ratio of 4-amino-1-methylpiperidine to N-ethylpiperazine is 5:1, and the concentration of the solute is 0.5 mol / kg.

[0091] The preparation method of the solid-liquid two-phase absorbent is as follows: 4-amino-1-methylpiperidine, N-ethylpiperazine and N-methylpyrrolidone are placed and mixed and stirred to obtain the solid-liquid two-phase absorbent.

[0092] Example 4

[0093] An embodiment of the present invention provides a solid-liquid two-phase absorbent, which is composed of 4-aminopiperidine, N-isopropylpiperazine and N-ethylpyrrolidone, wherein the molar ratio of 4-aminopiperidine to N-isopropylpiperazine is 5:1, and the concentration of the solute is 0.5 mol / kg.

[0094] The preparation method of the solid-liquid two-phase absorbent is as follows: 4-aminopiperidine, N-isopropylpiperazine and N-ethylpyrrolidone are placed and mixed and stirred to obtain the solid-liquid two-phase absorbent.

[0095] Example 5

[0096] An embodiment of the present invention provides a solid-liquid two-phase absorbent, which is composed of 4-amino-1-methylpiperidine, 2-methylpiperazine and N-methylpyrrolidone, wherein the molar ratio of 4-amino-1-methylpiperidine to 2-methylpiperazine is 9:1, and the concentration of 4-amino-1-methylpiperidine is 0.5 mol / kg.

[0097] The preparation method of the solid-liquid two-phase absorbent is as follows: 4-amino-1-methylpiperidine and 2-methylpiperazine are placed in N-methylpyrrolidone, mixed and stirred to obtain the solid-liquid two-phase absorbent.

[0098] Example 6

[0099] An embodiment of the present invention provides a solid-liquid two-phase absorbent, which is composed of 4-amino-1-methylpiperidine, 2-methylpiperazine and N-methylpyrrolidone, wherein the molar ratio of 4-amino-1-methylpiperidine to 2-methylpiperazine is 3:2, and the concentration of 4-amino-1-methylpiperidine is 0.5 mol / kg.

[0100] The preparation method of the solid-liquid two-phase absorbent is as follows: 4-amino-1-methylpiperidine and 2-methylpiperazine are placed in N-methylpyrrolidone, mixed and stirred to obtain the solid-liquid two-phase absorbent.

[0101] Comparative Example 1

[0102] An embodiment of the present invention provides a solid-liquid two-phase absorbent, which is composed of 4-amino-1-methylpiperidine and N-methylpyrrolidone, wherein the concentration of 4-amino-1-methylpiperidine is 0.5 mol / kg.

[0103] The preparation method of the solid-liquid two-phase absorbent is as follows: 4-amino-1-methylpiperidine is placed in N-methylpyrrolidone, and the mixture is mixed and stirred to obtain the solid-liquid two-phase absorbent.

[0104] Comparative Example 2

[0105] The comparative example of the present invention provides a solid-liquid two-phase absorbent, which is composed of 4-amino-1-methylpiperidine, piperazine and N-methylpyrrolidone, wherein the molar ratio of 4-amino-1-methylpiperidine to piperazine is 5:1, and the concentration of 4-amino-1-methylpiperidine is 0.5 mol / kg.

[0106] The preparation method of the solid-liquid two-phase absorbent is as follows: 4-amino-1-methylpiperidine, piperazine and N-methylpyrrolidone are placed and mixed and stirred to obtain the solid-liquid two-phase absorbent.

[0107] Comparative Example 3

[0108] The comparative example of the present invention provides a solid-liquid two-phase absorbent, which is composed of 1-methylpiperidine, 2-methylpiperazine and N-methylpyrrolidone, wherein the molar ratio of 1-methylpiperidine to 2-methylpiperazine is 5:1, and the concentration of 1-methylpiperidine is 0.5 mol / kg.

[0109] The preparation method of the solid-liquid two-phase absorbent is as follows: 1-methylpiperidine, 2-methylpiperazine and N-methylpyrrolidone are placed and mixed and stirred to obtain the solid-liquid two-phase absorbent.

[0110] Experiment 1

[0111] The solid-liquid mixture formed by the reaction of the solid-liquid two-phase absorbent and carbon dioxide in Example 1 and Comparative Example 1 was filtered and separated. Photos were then taken for comparison, with the solid phase of Comparative Example 1 labeled as Figure a and the solid phase of Example 1 labeled as Figure b.

[0112] pass Figure 1 Comparison of Figures a and b in FIG shows that the solid phase of Comparative Example 1 is in a viscous state (9300 mPa·s). The viscous solid phase easily forms a large volume of precipitation in the organic solvent, causing the solid-liquid two-phase absorbent of Comparative Example 1 to easily clog the pipeline after absorbing carbon dioxide. The solid phase of Example 1 is in a powdery state (3600 mPa·s). The powdery product is easily dispersed in the organic solvent, which can effectively improve the problem of pipeline clogging.

[0113] Experiment 2

[0114] Carbon dioxide performance test

[0115] At 40°C, flue gas containing 15% volume concentration of carbon dioxide was introduced into 100g of solid-liquid two-phase absorbent (flow rate of 400 ml / min). After absorption, the gas spontaneously separated into two layers, with the upper layer being the organic phase and the lower layer being the solid phase, and carbon dioxide was enriched in the solid phase.

[0116] The solid volume percentage, carbon dioxide absorption, solid product state and solid product viscosity are tested.

[0117] Solid volume fraction refers to the volume fraction of solid volume to the sum of solid and liquid volumes. The test method is to separate the reaction product into solid and liquid by filtration, measure the liquid volume and total volume respectively using a graduated cylinder, and calculate the percentage of solid volume to total volume according to (total volume - liquid volume) / total volume;

[0118] The test method for carbon dioxide absorption is as follows: the concentration change of CO2 during the absorption process is monitored by a flue gas analyzer (GASTiger6000-2L), the total volume of CO2 absorbed is obtained by integrating the curve graph of time and concentration change and multiplying it by the flue gas flow rate, and then converted to molar amount and divided by the molar amount of amine to obtain the absorption amount (unit: mol / mol amine).

[0119] The state of the solid product was determined by visual inspection.

[0120] The viscosity test method of the solid product is as follows: the solid separated by filtration is taken out and placed in a rotational viscometer container at room temperature for viscosity testing.

[0121] The test results of the above embodiments and comparative examples are shown in Table 1.

[0122] Table 1

[0123]

[0124] According to the comparative data of Example 1 and Comparative Example 1 in Table 1, the solid-liquid two-phase absorbent using a combination of piperidine derivatives and piperazine derivatives shows significant advantages in carbon dioxide capture performance. The absorbent of Example 1 not only achieves a higher carbon dioxide absorption capacity, but also the solid product generated by the reaction is in the form of a powder that is not easy to aggregate, and the solid product has a lower viscosity and a lower solid volume ratio. This effectively alleviates the adhesion tendency of the solid-phase product in the reaction pipeline, allowing the gas-liquid mass transfer process to proceed continuously and stably. In contrast, the solid product generated by the reaction of Comparative Example 1 is viscous and has a higher solid volume. Product agglomeration and pipeline blockage are prone to occur during the use of the adsorbent.

[0125] Combined with the experimental results of Comparative Example 2, it was found that the piperazine ring was not alkyl-substituted. Although the generated product was in powder form, the solid product had a high solid volume ratio, and the solid product still had a high viscosity in the organic solvent, and still had a high risk of aggregation and clogging the reaction pipe.

[0126] Further analysis of the experimental results of Comparative Example 3 revealed that piperidine was not substituted with primary amine, and the resulting solid product morphology was similar to that of Comparative Example 1, both being viscous and having high viscosity and a high solid volume fraction.

[0127] Combining Comparative Examples 2 and 3, it can be seen that the present application, by constructing a primary amine active site in the piperidine derivative molecule and coordinating with the synergistic effect of piperazine ring alkylation modification, can effectively coordinate and regulate the morphology of the reaction product and achieve an effective reduction in the viscosity of the solid product, thereby breaking through the mass transfer limitation bottleneck of the solid-liquid absorption system in engineering applications.

[0128] The solid-liquid two-phase absorbent disclosed in the embodiments of the present invention, its preparation method, and application are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the solid-liquid two-phase absorbent and its preparation method, application, and core concept of the present invention. At the same time, for those skilled in the art, according to the concept of the present invention, there may be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A solid-liquid two-phase absorbent, characterized in that: It includes piperidine derivatives, piperazine derivatives and organic solvents, wherein the piperidine derivatives contain primary amine groups and the piperazine derivatives contain alkyl groups; The piperazine derivatives include one or more combinations of 2-methylpiperazine, 2,6-dimethylpiperazine, N-methylpiperazine, N-ethylpiperazine, and N-isopropylpiperazine; The piperidine derivatives include one or more combinations of 4-aminopiperidine, 4-amino-1-methylpiperidine, 2-amino-1-methylpiperidine, 3-aminopiperidine, 2,5-diaminopiperidine or 4-amino-1-piperidine propanol; The organic solvent has a viscosity of 0.8 mPa·s to 2.5 mPa·s and includes one or more of N-methylpyrrolidone, dimethylacetamide, dimethyl sulfoxide, or N-ethylpyrrolidone.

2. The solid-liquid two-phase absorbent according to claim 1, characterized in that The molar ratio of the piperidine derivative to the piperazine derivative is (9:1) to (3:2).

3. The solid-liquid two-phase absorbent according to claim 2, characterized in that The total concentration of the piperidine derivative and the piperazine derivative is 0.5 mol / kg to 3 mol / kg.

4. A method for preparing the solid-liquid two-phase absorbent according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: placing the piperidine derivative and the piperazine derivative in the organic solvent and mixing and stirring to obtain the solid-liquid two-phase absorbent.

5. Use of the solid-liquid two-phase absorbent according to any one of claims 1 to 4, characterized in that: To capture carbon dioxide, The method comprises the following steps: introducing a gas containing carbon dioxide into the solid-liquid two-phase absorbent at a temperature of 30° C. to 60° C.; after absorbing the gas containing carbon dioxide, the solid-liquid two-phase absorbent spontaneously separates into layers, wherein the upper layer is an organic phase and the lower layer is a solid phase.

6. The use of the solid-liquid two-phase absorbent according to claim 5, characterized in that: The carbon dioxide is enriched in the solid phase, the enrichment of the carbon dioxide in the solid phase is 85% to 95%, and the particle size of the solid phase is 1 μm to 100 μm.

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