Solid adsorbents and methods for their preparation

Abstract

The present application relates to a kind of solid adsorbents and its preparation method.Solid adsorbent is made of porous solid carrier and load two parts.Porous solid carrier includes molecular sieve, silica gel, alumina, hydrotalcite and its derivatives.Load is made of main agent and auxiliary agent, wherein main agent is the polyamide-amine of amine group and hydroxyl group modified end group, and the molar ratio of amine group and hydroxyl group is 1:1-1:1.5;Auxiliary agent is one or several of AMP, hydroxyethylpiperazine (HPZ), 1,8-diazabicyclo (7-undecene) (DBU), sulfolane (TS).Load is 25%-150% of the weight of porous solid carrier, and the mass fraction of main agent in load is 35%-80%.The present application has selective adjustable, adsorption speed is fast, adsorption capacity is large, and the removal rate of COS, methyl mercaptan, ethyl mercaptan and other organic sulfur is high.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of gas purification technology in the industries of energy, petroleum chemical industry, environmental protection, etc., and relates to a solid adsorbent for selectively removing H2S and COS, methyl mercaptan, ethyl mercaptan and other organic sulfur from a gas mixture, in particular to a solid adsorbent and a preparation method thereof. BACKGROUND

[0002] There are many occasions in industry that require selective removal of one or several of H2S, COS, mercaptan and other acidic impurities in a gas mixture, such as natural gas, refinery catalytic dry gas, coking dry gas, coal bed gas, marsh gas, landfill gas, and synthetic gas prepared from coal, petroleum brain, heavy oil, biomass gasification, etc. There are many mature process methods for the separation of H2S, such as chemical absorption method, physical absorption method, adsorption method, etc.

[0003] For the chemical absorption method, the use of alcohol amine as a solvent is called amine method, and the use of potassium carbonate is called hot potassium base method. The commonly used alcohol amine includes monoethanolamine (MEA), diethanolamine (DEA), N-methyldiethanolamine (MDEA), diglycolamine (DGA), etc. The hot potassium base method uses potassium carbonate as the main absorbent, and cooperates with DEA or boric acid as an activator. Whether it is the amine method or the hot potassium base method, the absorption liquid contains 30%-70% or even 90% water. This part of water needs to be heated and vaporized in the absorption liquid regeneration process, and the regenerated absorption liquid needs to be cooled and cooled again when it returns to the absorption tower for absorption. At the same time, a large amount of water vapor needs to be generated in the regeneration tower, and then condensed and cooled back to the regeneration tower. Therefore, for the chemical absorption method, there is a lot of heat wasted in the heating and cooling process of water.

[0004] The physical absorption method is widely used according to the fact that the solubility of H2S, COS, methyl mercaptan and other acidic impurities in the physical solvent is much greater than that of CH4, H2, CO and other effective components. The physical absorption method commonly uses methanol (such as Rectisol method), polyethylene glycol dimethyl ether (such as NHD method, Selexol method), N-methyl pyrrolidone (such as Purisol method) and other solvents as absorbents. Compared with the chemical absorption method, the physical absorption method not only has a simple process, but also has low energy consumption. However, the physical absorption method requires a relatively high partial pressure of the components to be removed, and the absorption operation pressure is also relatively high. At the same time, the full contact of heavy components in the mixed gas with the physical solvent also causes excessive absorption of heavy components, resulting in large loss or making the absorption liquid deteriorate and become unusable.

[0005] Adsorption method often uses molecular sieve, activated carbon, silica gel, alumina and other porous media as adsorbent. For the current industrial applications, porous media can remove a variety of components at room temperature by physical adsorption, but with the increase of adsorption temperature, the adsorption capacity decreases, and the adsorption capacity and selectivity of the adsorbent are not high enough at low temperature. Moreover, most of the current adsorbents have single function and are not suitable for treating mixed gas containing H2S and COS, CS2, mercaptan and other organic sulfur.

[0006] In order to reduce the energy consumption of the process of removing acidic impurities, improve the adsorption capacity and selectivity of the adsorbent, researchers began to load basic substances on the surface of porous adsorbent, among which the solid adsorbent loaded with amine compounds is called solid amine. The current research on solid amine is almost designed for removing CO2, and the amine compounds used include MEA, DEA, MDEA, AMP, diisopropanolamine (DIPA), diethylene triamine (DETA), tetraethylene pentamine (TEPA), pentaethylene hexamine (PEHA), and different molecular weight polyethylene imine (PEI).

[0007] Chinese patent application CN95119387.2 discloses a method for preparing solid amine resin. Chinese patent CN200780029796.1 discloses a solid adsorbent prepared by loading MEA, DEA and other amine compounds on carriers such as nano-silicon dioxide, silicon dioxide-alumina, calcium silicate and the like, and loading glycerol, ethylene glycol, polyethylene glycol and the like, to enhance the removal of CO2. Chinese patent CN200880124187.9 discloses the use of silica, zeolite, activated carbon to load TEPA and other alkyl amines or aromatic amines to remove CO2. Chinese patent CN201010125416.8 discloses a method for preparing solid amine by loading PEI on coal gangue. Chinese patent CN201110091696.X discloses the preparation of solid amine by loading TEPA or PEI on carbon nanotubes, and the adsorption capacity of 1.5-2.2 vol% CO2 reaches 2.45 mmol / g. Chinese patent CN201210042863.6 discloses a process for removing H2S and CO2 from synthesis gas using solid amine. Chinese patent CN201110165456.X and Chinese patent CN201120207786.6 respectively disclose devices for purifying CO2 in vehicles using solid amine. Chinese patent CN201310566423.5 discloses a device for removing CO2 from air conditioner pipes using solid amine. The solid amine adsorbent can be used in fixed bed, moving bed and other reactors, and one or more of heat regeneration, vacuum regeneration, steam regeneration and gas stripping regeneration can be used for regeneration.

[0008] It can be seen that the current selective desulfurization is mainly liquid absorption method, which has repeated vaporization, condensation and cooling of water in the solution regeneration process, resulting in high energy consumption.

[0009] In view of the deficiencies of the chemical absorption method, the physical absorption method and the conventional adsorption method in removing H2S and COS, methyl mercaptan and other organic sulfur, and considering the advantages of the solid amine, the application combines the advantages of the chemical absorption method and the adsorption method, and proposes a solid amine modified by a special amine, which is used for selectively removing H2S and COS, methyl mercaptan and other organic sulfur from mixed gas, and realizes the characteristics of high selectivity, high desulfurization precision and low energy consumption. SUMMARY

[0010] The main purpose of the application is to overcome the defects of the existing solid adsorbent for removing H2S and organic sulfur in mixed gas, and to provide a solid adsorbent for selectively removing H2S, COS, methyl mercaptan, ethyl mercaptan and other organic sulfur from mixed gas containing H2S, COS, methyl mercaptan, ethyl mercaptan and other organic sulfur, so as to solve the technical problem of obtaining high desulfurization precision and low energy consumption, thereby being more suitable for practical use and having industrial application value.

[0011] Another purpose of the application is to provide a preparation method of the solid adsorbent for selectively removing H2S and organic sulfur in mixed gas, so as to solve the technical problem of making it more uniform, controllable and efficient, thereby being more suitable for practical use.

[0012] The application has obvious advantages and beneficial effects compared with the prior art. As can be seen from the above technical solution, in order to achieve the aforementioned application purposes, the main technical contents of the application are as follows:

[0013] The solid adsorbent of the application can be used in conventional fixed bed, moving bed and other reactors, has the advantages of adjustable selectivity, fast adsorption speed, large adsorption capacity and can effectively remove COS, methyl mercaptan, ethyl mercaptan and other organic sulfur, and can be used for desulfurization and decarburization at low temperature.

[0014] The solid adsorbent of the application is composed of a porous solid carrier and a load. The porous solid carrier includes molecular sieve, silica gel, alumina, hydrotalcite and its derivatives. The load is composed of a main agent and an auxiliary agent, wherein the main agent is polyamide-amine, and the auxiliary agent is one or more of 2-amino-2-methyl-1-propanol (AMP), hydroxyethylpiperazine (HPZ), 1,8-diazabicyclo (7-undecene) (DBU) and sulfolane (TS), preferably 1-2 kinds. The load is 25%-150% of the weight of the porous carrier, and the mass fraction of the main agent in the load is 35%-80%.

[0015] The main agent PAMAM in the application can be a compound of a certain generation of PAMAM or a mixture of PAMAMs with different generations when used. PAMAM is a polymer prepared by using ethylenediamine, propylenediamine as the core, methyl acrylate as the branch, using monoethanolamine to realize the hydroxylation of the terminal group, and through the divergent method. The diamine as the core of PAMAM can be different from the diamine for the amidation reaction.

[0016] The terminal group of the main agent PAMAM in the application is an amine group and a hydroxyl group, and the molar ratio of the amine group to the hydroxyl group is 1:1-1:1.5.

[0017] Methanol, or ethanol, or a mixture of methanol and ethanol is used as a dispersant when the solid adsorbent in the application is prepared. The preparation process generally includes the following steps: (1) a certain mass of porous solid carrier is dispersed in a dispersant to form a suspension A, and a certain mass and ratio of the main agent and the auxiliary agent are dissolved in the dispersant to form a solution B; (2) B is added during the stirring of A; (3) the mixture of A and B is left to stand, and stirring is continued for a period of time at intervals; (4) the dispersant is removed by vacuum drying to obtain the solid adsorbent.

[0018] For the application, the mixed gas containing one or more of H2S and COS, methyl mercaptan, ethyl mercaptan is not limited to refinery catalytic dry gas, coking dry gas and liquefied gas, natural gas, coal bed gas, biogas, landfill gas, synthetic gas converted from coal, naphtha, heavy oil, residual oil, biomass, etc., flue gas.

[0019] For the application, the content of the main agent in the support and the composition and content of the auxiliary agent are adjusted according to the composition of the gas source and the adsorption operating conditions (temperature and pressure) when used.

[0020] For the application, the mixed gas contains water or does not contain water.

[0021] The preparation method of the solid adsorbent provided by the application effectively utilizes methanol, ethanol or a mixture thereof as a dispersant through carefully designed steps to ensure that the porous solid carrier, the main agent and the auxiliary agent can be uniformly mixed and form a good adsorbent structure. The following is a detailed description of the preparation method.

[0022] 1. Disperse the porous solid carrier:

[0023] (1) Select a porous solid carrier as the basic material because it has good adsorption performance and certain mechanical strength.

[0024] (2) Disperse the porous solid carrier in methanol, ethanol or a mixture of the two to form a suspension A. The purpose of this step is to uniformly disperse the carrier particles to lay the foundation for the subsequent mixing process.

[0025] 2. Dissolving the main agent and the auxiliary agent:

[0026] (2) The main agent is usually a chemical substance with specific adsorption functions, while the auxiliary agent is used to adjust the performance of the adsorbent, such as improving adsorption efficiency and enhancing stability.

[0027] (3) Dissolve the main agent and the auxiliary agent in the same dispersant as the suspension A to form solution B. This ensures that the main agent and the auxiliary agent are evenly distributed on the carrier particles during subsequent mixing.

[0028] 3. Mixing the suspension A and the solution B:

[0029] (1) Gradually add solution B while stirring the suspension A. The purpose of stirring is to ensure that the main agent and the auxiliary agent in solution B can fully penetrate the interior and surface of the carrier particles.

[0030] (2) By controlling the stirring speed and stirring time, the mixing effect can be optimized to ensure uniform distribution of the main agent and the auxiliary agent on the carrier.

[0031] 4. Rest and re-stirring:

[0032] (1) After mixing is complete, let the mixture of A and B stand for a period of time. This step helps the components in the mixture to further interact and integrate.

[0033] (2) After a certain period of time, the mixture is stirred again. This step helps to eliminate possible stratification or precipitation phenomena, ensuring the uniformity of the mixture.

[0034] 5. Vacuum drying to remove the dispersant:

[0035] (1) Finally, the dispersant is removed by vacuum drying. Vacuum drying can provide lower temperature and higher drying efficiency, which helps to maintain the structure and performance of the adsorbent.

[0036] (2) After removing the dispersant, the desired solid adsorbent is obtained.

[0037] It is known from the above that the present application belongs to the field of gas purification technology in the energy, petrochemical industry, environmental protection and other industries, and specifically relates to a solid adsorbent for selectively removing H2S, COS, methyl mercaptan, ethyl mercaptan and other organic sulfur from a gas mixture. The solid adsorbent is composed of a porous solid carrier and a load. The porous solid carrier includes molecular sieves, silica gel, alumina, hydrotalcite and its derivatives. The load is composed of a main agent and an auxiliary agent, wherein the main agent is a polyamide-amine modified with amine groups and hydroxyl groups at the end, and the molar ratio of amine groups to hydroxyl groups is 1:1-1:1.5; the auxiliary agent is one or several of AMP, hydroxyethylpiperazine (HPZ), 1,8-diazabicycloundec-7-ene (DBU), and sulfolane (TS). The load is 25%-150% of the weight of the porous solid carrier, and the mass fraction of the main agent in the load is 35%-80%. The solid adsorbent of the present application is used for desulfurization and decarburization, and can be used in conventional fixed bed, moving bed and other reactors at low temperature, with adjustable selectivity, fast adsorption speed, large adsorption capacity, and high removal rate of COS, methyl mercaptan, ethyl mercaptan and other organic sulfur.

[0038] Through the above technical solution, the solid adsorbent for selectively removing H2S and organic sulfur from a mixed gas at least has the following advantages:

[0039] The present application scheme is a solid adsorption method, which avoids repeated vaporization, condensation and cooling in the selective desulfurization process. The prepared adsorbent can selectively remove H2S, COS, methyl mercaptan, ethyl mercaptan and other organic sulfur from a mixed gas containing H2S and COS, methyl mercaptan, ethyl mercaptan and other organic sulfur at low pressure and high pressure, and high desulfurization precision is obtained.

[0040] The adsorbent proposed in the present application is suitable for the purification treatment of various sulfur-containing gases, including but not limited to catalytic dry gas, coking dry gas, natural gas, coal bed gas, biogas, landfill gas, and synthetic gas and flue gas converted from coal, naphtha, heavy oil, residual oil, biomass and the like.

[0041] The present application has important significance for reducing the content of harmful sulfur compounds in industrial emissions and protecting the environment. At the same time, it also embodies the combination of material science and chemical process, and has a broad prospect in practical application.

[0042] The preparation method proposed in the present application has the following advantages.

[0043] (1) Uniformity: Through careful design of mixing and stirring steps, uniform distribution of the main agent, auxiliary agent and carrier particles is ensured.

[0044] (2) Controllability: The type of dispersing agent, the type and amount of main agent and auxiliary agent, stirring speed and time and other parameters can be adjusted according to needs to prepare adsorbents with different properties.

[0045] (3) High efficiency: the vacuum drying method improves the drying efficiency, which helps to shorten the preparation period and reduce the cost.

[0046] In summary, the preparation method of the solid adsorbent has the advantages of simple preparation process, strong controllability, high efficiency, excellent adsorption performance, etc. By optimizing the preparation conditions, solid adsorbents that meet different application requirements can be prepared.

[0047] In summary, the solid adsorbent for selectively removing H2S and organic sulfur in mixed gas has many advantages and practical value as described above, and there is no similar design published or used, which is innovative and has made great progress in technology, and has good and practical effects.

[0048] The above description is only a summary of the technical solutions of the present application. In order to more clearly understand the technical means of the present application and can be implemented according to the content of the specification, the following will be described in detail as follows. DETAILED DESCRIPTION

[0049] In order to further illustrate the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following will be described in detail as follows according to the preferred embodiments of the solid adsorbent for selectively removing H2S and organic sulfur in mixed gas.

[0050] The proportions of various components in the solid adsorbent in the examples are mass fractions, and the composition of the gas is calculated by volume fraction.

[0051] The solid amine adsorbent is as follows:

[0052] Methanol is used as a dispersant, the porous solid carrier is amorphous silica gel Q-10 (the silica gel degree of the amorphous silica gel is 10), the mass of the load is 35% of Q-10, the main agent in the load is 2 generation PAMAM, and the proportions of the main agent and the auxiliary agent are 75% and 25% respectively. The proportion of terminal amine groups to hydroxyl groups in 2 generation PAMAM is 1:1. The auxiliary agent composition is AMP and HPZ, wherein HPZ and AMP are both 50%. The solid adsorbent prepared therefrom is marked as SA-1.

[0053] Methanol is used as a dispersant, the porous solid carrier is amorphous silica gel Q-10, the mass of the load is 80% of Q-10, the main agent in the load is 2 generation PAMAM, and the proportions of the main agent and the auxiliary agent are 50% and 50% respectively. The proportion of terminal amine groups to hydroxyl groups in 2 generation PAMAM is 1:1. The auxiliary agent composition is AMP and DBU, wherein DBU and AMP are 40% and 60% respectively. The solid adsorbent prepared therefrom is marked as SA-2.

[0054] Methanol was used as dispersant, porous solid support was amorphous silica gel Q-10, loading was 150% of Q-10, main agent in loading was 2nd generation PAMAM, and the ratio of main agent and auxiliary agent was 35% and 65% respectively. The ratio of terminal amine group and hydroxyl group in 2nd generation PAMAM was 1:1. The auxiliary agent was composed of DBU and HPZ, in which DBU and HPZ were 20% and 80% respectively. The solid adsorbent thus prepared was marked as SA-3.

[0055] Methanol was used as dispersant, porous solid support was molecular sieve MCM-41 (nanostructured material), loading was 45% of MCM-41, main agent in loading was 3rd generation PAMAM, and the ratio of main agent and auxiliary agent was 70% and 30% respectively, and the auxiliary agent was composed of only AMP. The solid adsorbent thus prepared was marked as SA-4.

[0056] Methanol was used as dispersant, porous solid support was molecular sieve MCM-48, loading was 85% of MCM-48, main agent in loading was 4th generation PAMAM, and the ratio of main agent and auxiliary agent was 70% and 30% respectively, and the auxiliary agent was composed of only TS. The solid adsorbent thus prepared was marked as SA-5.

[0057] Ethanol was used as dispersant, porous solid support was alumina, loading was 125% of alumina, main agent in loading was 4th generation PAMAM, and the ratio of main agent and auxiliary agent was 50% and 50% respectively. The auxiliary agent was composed of only TS (cyclobutane sulfone). The solid adsorbent thus prepared was marked as SA-6.

[0058] Ethanol was used as dispersant, porous solid support was hydrotalcite, loading was 30% of hydrotalcite, main agent in loading was 1st generation PAMAM, and the ratio of main agent and auxiliary agent was 70% and 30% respectively. The auxiliary agent was composed of DBU and TS, in which DBU and TS were 40% and 60% respectively. The solid adsorbent thus prepared was marked as SA-7.

[0059] Example 1

[0060] The mixed gas table pressure was 6 kPa, CO2 content was 3.5%, and the rest was N2. The adsorption temperature was 40°C, the mixed gas was saturated at the adsorption temperature after passing through water bath, and then passed through the adsorption column filled with the above different solid adsorbents, and the breakthrough adsorption capacity result at space velocity of 550 was shown in Table 1.

[0061] Table 1:

[0062] Adsorbent Absorption capacity mmol / g SA-1 0.53 SA-2 0.51 SA-3 0.54 SA-4 0.55 SA-5 0.48 SA-6 0.49 SA-7 0.50

[0063] Example 2

[0064] The mixed gas had a gauge pressure of 6 kPa, an H2S content of 3.5%, and the remainder was N2. The adsorption temperature was 40℃. After the mixed gas was saturated in a water bath at the adsorption temperature, it was passed through an adsorption column packed with the above-mentioned different solid adsorbents. The breakthrough adsorption capacity at a space velocity of 550 is shown in Table 2.

[0065] Table 2:

[0066] Adsorbent Absorption capacity mmol / g SA-1 4.67 SA-2 4.59 SA-3 4.73 SA-4 4.55 SA-5 4.53 SA-6 4.69 SA-7 4.81

[0067] Example 3

[0068] The mixed gas had a gauge pressure of 0.11 MPa, and the contents of H2S, CO2, COS, and methanethiol were 0.5%, 3.5%, 25 ppmv, and 55 ppmv, respectively, with the remainder being N2. The mixed gas was saturated in a water bath at 50℃ and then passed through an adsorption column packed with different solid adsorbents. The contents of each component in the purified gas at a space velocity of 550 are shown in Table 3 below.

[0069] Table 3:

[0070] Adsorbent [H2S (ppmv)] CO2 (v %) COS (ppmv) Methyl mercaptan (ppmv) SA-1 2.3 2.8 5.5 1.7 SA-2 2.1 2.7 5.2 1.6 SA-3 1.8 2.6 4.9 1.5 SA-4 2.5 2.9 5.1 1.8 SA-5 2.9 3.1 5.7 2.3 SA-6 3.1 3.2 5.3 2.6 SA-7 1.5 2.4 4.4 1.0

[0071] Example 4

[0072] The mixed gas had a gauge pressure of 1 MPa, and the contents of H2S, CO2, COS, and methanethiol were 0.5%, 3.5%, 25 ppmv, and 55 ppmv, respectively, with the remainder being N2. The mixed gas was saturated in a water bath at 50℃ and then passed through an adsorption column packed with different solid adsorbents. The contents of each component in the purified gas at a space velocity of 1000 are shown in Table 4.

[0073] Table 4:

[0074] Adsorbent [H2S (ppmv)] CO2 (v %) COS (ppmv) Methyl mercaptan (ppmv) SA-1 2.9 3.3 5.8 2.0 SA-2 2.7 3.2 5.5 1.8 SA-3 2.6 3.1 5.3 1.9 SA-4 3.3 3.3 5.4 2.1 SA-5 3.7 3.6 6.1 2.7 SA-6 4.0 3.5 5.7 2.8 SA-7 2.3 2.8 4.9 1.3

[0075] Examples 1 and 2 show that the prepared adsorbent has a large adsorption capacity for H2S, exhibiting good selectivity. Examples 3 and 4 show that the prepared adsorbent can achieve good selective desulfurization results under both low and high pressures.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the methods and techniques disclosed above without departing from the scope of the present invention to create equivalent embodiments. Any simple modifications, equivalent changes and alterations 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 scope of the present invention.

Claims

1. A solid adsorbent for selectively removing H 2 S and COS, methyl mercaptan and ethyl mercaptan from a mixed gas, the solid adsorbent being composed of a porous solid carrier and a load, wherein the porous solid carrier is selected from at least one of molecular sieve, silica gel, alumina, hydrotalcite and derivatives thereof; the load comprises a main agent and an auxiliary agent, the main agent is a polyamide-amine (PAMAM) modified with amine group and hydroxyl group at the terminal group, and the auxiliary agent is at least one of AMP, hydroxyethylpiperazine (HPZ), 1,8-diazabicycloundec-7-ene (DBU) and sulfolane (TS), the load accounts for 25% to 150% of the weight of the porous solid carrier, and the mass fraction of the main agent in the load is 35% to 80%. The PAMAM is a modified compound with hydroxyl group at the terminal group, wherein the molar ratio of amine group to hydroxyl group ranges from 1:1 to 1:1.

5. 2.The solid adsorbent according to claim 1, wherein the main agent PAMAM is synthesized by using ethylenediamine or propylenediamine as the starting core and ethylenediamine or propylenediamine as the branched chain amidation reagent, and the terminal group is modified by using ethanolamine when hydroxylated. 3.The solid adsorbent according to claim 2, wherein the diamine as the PAMAM core is different from the diamine used in the amidation reaction. 4.The solid adsorbent according to claim 1, wherein the PAMAM is any one of 1 to 5 generations, or a mixture of PAMAMs with different generations. 5.The solid adsorbent according to claim 1, wherein the mixed gas is selected from refinery catalytic dry gas, coking dry gas and liquefied gas, natural gas, coal bed gas, marsh gas, landfill gas, or synthetic gas or flue gas converted from coal, naphtha, heavy oil and residual oil. 6.The solid adsorbent according to claim 1 or 5, wherein the gas space velocity during use of the solid adsorbent is 400-1200. 7.A preparation method of the solid adsorbent according to claim 1, wherein the method comprises the following steps: dispersing the porous solid carrier with a dispersant to form a suspension A; dissolving the main agent and the auxiliary agent with a dispersant to form a solution B; mixing the suspension A and the solution B; standing and stirring again; and vacuum drying to remove the dispersant to obtain the solid adsorbent. 8.The preparation method according to claim 7, wherein the porous solid carrier is selected from at least one of molecular sieve, silica gel, alumina, hydrotalcite and derivatives thereof; the main agent is polyamide-amine (PAMAM) modified with amine group and hydroxyl group at the terminal group; the auxiliary agent is at least one of AMP, hydroxyethylpiperazine (HPZ), 1,8-diazabicycloundec-7-ene (DBU) and sulfolane (TS); and the dispersant is methanol, ethanol or a mixture of methanol and ethanol. 9.The preparation method according to claim 7, wherein the main agent and the auxiliary agent account for 25% to 150% of the weight of the porous solid carrier, and the mass fraction of the main agent in the main agent and the auxiliary agent is 35% to 80%.