A method for separating an acetylene / carbon dioxide mixture

Abstract

The present application relates to the technical field of gas separation, and discloses a method for separating acetylene / carbon dioxide mixed gas, which comprises: contacting and adsorbing acetylene / carbon dioxide mixed gas with a carbon dioxide adsorbent to obtain purified acetylene-containing gas; the concentration of carbon dioxide in the acetylene / carbon dioxide mixed gas is ≤5v%; the carbon dioxide adsorbent contains a porous carrier material and an amino active component, and the amino active component is loaded on the porous carrier material by grafting and / or impregnation. The carbon dioxide adsorbent provided by the present application has the characteristics of low regeneration temperature, good cycle performance, low production cost and environmental friendliness when applied to acetylene / carbon dioxide mixed gas.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of gas separation, in particular to a method for separating acetylene / carbon dioxide mixed gas. BACKGROUND

[0002] Acetylene is an important chemical raw material, and also an important energy gas. Acetylene is mainly produced by partial combustion of methane and cracking of petroleum hydrocarbons. Acetylene crude generally contains impurity gases such as carbon dioxide. In order to obtain high-purity acetylene, the impurity gases need to be removed. However, the size and boiling point of acetylene and carbon dioxide molecules are very similar, making it extremely difficult to separate these two gases. Traditional separation methods, such as solvent extraction and low-temperature rectification, have the disadvantages of high cost and high energy consumption, and the use of lye to absorb carbon dioxide in acetylene is easy to corrode equipment and is not environmentally friendly.

[0003] In contrast, the use of porous materials to achieve the adsorption separation of acetylene / carbon dioxide is more energy-saving and environmentally friendly. In particular, the application of metal-organic framework materials in acetylene / carbon dioxide separation is attracting more and more attention from researchers. CN114367270A, CN108503851A and CN113019330A all disclose methods for separating acetylene and carbon dioxide using metal-organic framework materials. These prior arts can selectively adsorb and store C2H2 and effectively prevent the storage of CO2, although they can achieve the separation of acetylene and carbon dioxide, the carbon dioxide adsorption capacity is low, not suitable for separating low-concentration carbon dioxide in acetylene, and difficult to be used on a large scale.

[0004] CN114307976A discloses an adsorbent and its application in the separation of carbon dioxide / acetylene mixed gas. Under certain temperature and pressure conditions, carbon dioxide / acetylene mixed gas is introduced into an adsorption column containing the adsorbent, and carbon dioxide impurity gas is preferentially adsorbed, and high-purity acetylene can be directly collected at the outlet end. However, the separation ratio of this prior art is low, and the regulated yttrium nitrate hexahydrate is used, which is difficult to promote on a large scale.

[0005] Therefore, it is urgent to develop a material with good adsorption performance, easy regeneration, and economic durability to separate carbon dioxide in acetylene. SUMMARY

[0006] The purpose of the present application is to overcome the aforementioned problems existing in the prior art, and to provide a carbon dioxide adsorbent with good adsorption performance, easy regeneration, and strong stability for acetylene / carbon dioxide mixed gas.

[0007] In order to achieve the above-mentioned purpose, the present application provides a method for separating acetylene / carbon dioxide mixed gas, characterized in that the method comprises:

[0008] contacting an acetylene / carbon dioxide mixed gas with a carbon dioxide adsorbent to obtain a purified acetylene gas, wherein the concentration of carbon dioxide in the acetylene / carbon dioxide mixed gas is ≤ 5v%;

[0009] The carbon dioxide adsorbent contains a porous carrier material and an amino active component, wherein the amino active component is loaded on the porous carrier material by grafting and / or impregnation;

[0010] The porous carrier material is provided by at least one selected from macroporous resin, molecular sieve, porous silica, porous alumina, activated carbon, and metal organic framework material.

[0011] The amino active component is provided by at least one selected from polyethyleneimine, tetraethylenepentamine, and diethanolamine.

[0012] The technical solution provided by the present application has the following beneficial effects:

[0013] (1) The carbon dioxide adsorbent provided by the present application has high carbon dioxide adsorption capacity and does not substantially adsorb acetylene when applied to an acetylene / carbon dioxide mixed gas, and has good selective adsorption.

[0014] (2) The carbon dioxide adsorbent provided by the present application can directly adsorb carbon dioxide in an environment with a carbon dioxide concentration of ≤ 5v% when applied to an acetylene / carbon dioxide mixed gas, and is suitable for adsorbing low-concentration carbon dioxide in an acetylene / carbon dioxide mixed gas.

[0015] (3) The carbon dioxide adsorbent provided by the present application has low regeneration temperature, good cycle performance, low production cost, and environmental friendliness when applied to an acetylene / carbon dioxide mixed gas. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a sample graph of the carbon dioxide adsorbent prepared in Preparation Example 1;

[0017] Figure 2 is a carbon dioxide / acetylene breakthrough curve of the carbon dioxide adsorbent prepared in Preparation Example 1;

[0018] Figure 3 is a thermogravimetric analysis curve of the carbon dioxide adsorbent prepared in Preparation Example 1;

[0019] Figure 4 is a minimum desorption temperature test curve of the carbon dioxide adsorbent prepared in Preparation Example 1;

[0020] Figure 5 is an acetylene / carbon dioxide adsorption curve of the carbon dioxide adsorbent prepared in Preparation Example 1;

[0021] Figure 6The carbon dioxide adsorbent prepared in Preparation Example 1 is used to prepare a carbon dioxide adsorption-desorption cycle curve. DETAILED DESCRIPTION

[0022] The endpoints of the ranges and any values claimed herein are presented as approximations. Unless otherwise stated, the endpoints of ranges are not to be understood as being limited to the precise values listed. Any value falling within the range is to be considered as having been specifically identified. Any numerical range recited is intended to include all sub-ranges subsumed therein. For ranges containing endpoints, names of quantities for both endpoints are meant as approximations.

[0023] Room temperature as used herein means 25±3℃.

[0024] Average pore diameter as used herein means average pore diameter.

[0025] Pressure as used herein means gauge pressure.

[0026] As described above, the present application provides a method for separating acetylene / carbon dioxide mixed gas, which comprises:

[0027] The acetylene / carbon dioxide mixed gas is contacted with a carbon dioxide adsorbent to obtain purified acetylene-containing gas; the concentration of carbon dioxide in the acetylene / carbon dioxide mixed gas is ≤5v%;

[0028] The carbon dioxide adsorbent comprises a porous carrier material and an amino active component, wherein the amino active component is loaded on the porous carrier material by grafting and / or impregnation;

[0029] The porous carrier material is provided by at least one selected from macroporous resin, molecular sieve, porous silica, porous alumina, activated carbon and metal organic framework material.

[0030] The amino active component is provided by at least one selected from polyethyleneimine, tetraethylenepentamine and diethanolamine.

[0031] The carbon dioxide adsorbent provided by the present application is prepared by loading organic amine into a porous carrier material by impregnation and / or grafting, and using the functional groups of the organic amine and the high specific surface area of the porous carrier material to improve the separation performance of acetylene and carbon dioxide.

[0032] Preferably, the conditions of the contact adsorption include a temperature of 0-100℃ and a pressure of 0.1-1.25MPa.

[0033] Preferably, the porous carrier material is macroporous resin and / or molecular sieve; and the amino active component is polyethyleneimine. The inventors of the present application have found in research that the carbon dioxide adsorbent prepared by using macroporous resin and / or molecular sieve as the porous carrier material and polyethyleneimine as the amino active component has more excellent adsorption performance and more excellent stability.

[0034] Preferably, the average pore size of the porous carrier material is 1.8-15 nm, preferably 3-9 nm, the specific surface area is 500-3500 m 2 / g, preferably 700-1200 m 2 / g; and the pore volume is 0.5-2 mL / g, preferably 0.8-1.8 mL / g.

[0035] Preferably, the weight average molecular weight of the polyethyleneimine is 300-1800 Da.

[0036] The macroporous resin used in the present application is prepared by polymerization of monomers and additives such as porogenic agents, and after the polymerization reaction is completed, the porogenic agents are removed, leaving interconnected pores in the resin, thus having a good macroporous network structure and a large specific surface area.

[0037] The specific source of the macroporous resin used in the present application is not particularly limited, and it can be prepared by known technical means in the art, or it can be purchased, as long as it can meet the parameter limitations described in the present application. However, the inventors of the present application have found in research that the carbon dioxide adsorbent prepared by using the macroporous resin of the following preferred conditions and in combination with the remaining technical features of the present application has more excellent adsorption and stability when applied to separate acetylene / carbon dioxide mixed gas. Preferably, the macroporous resin is selected from at least one of HP20 and D1400.

[0038] The metal organic framework material described in the present application is synthesized from metal ions (or metal clusters) and organic ligands, so that the metal organic framework material with suitable pore size and shape, high specific surface area and high pore rate, and good thermal and solvent stability can be designed according to the purpose of use.

[0039] The specific source of the metal organic framework material adopted in the present application is not particularly limited, and can be prepared by technical means known in the art, or can be obtained by purchase, as long as it can meet the parameter limit described in the present application. However, the inventors of the present application found in the research that the carbon dioxide adsorbent prepared by using the metal organic framework material under the following preferred conditions and combining the remaining technical features of the present application has more excellent adsorption and stability when applied to separate acetylene / carbon dioxide mixed gas. Preferably, the metal organic framework material is selected from at least one of MIL-101(Cr), ZIF-8, and UIO-66.

[0040] The porous silica described in the present application is preferably synthesized by a template method or a precipitation method, and the surface is modified with abundant hydroxyl groups, which is beneficial to the grafting and loading of organic amines.

[0041] Preferably, the carbon dioxide adsorption capacity of the carbon dioxide adsorbent is ≥50 mL / g, the regeneration temperature is 40-150℃, the maximum stable temperature is ≥180℃, and more preferably the maximum stable temperature is ≥250℃.

[0042] According to a preferred specific embodiment, the preparation method of the carbon dioxide adsorbent comprises: mixing and reacting the porous carrier material and the amino active component in the presence of solvent I to obtain the carbon dioxide adsorbent; and the mass ratio of the use amount of the porous carrier material to the amino active component is 1:0.5-1.5.

[0043] Preferably, the mass ratio of the use amount of the porous carrier material to the amino active component is 1:0.8-1.2. The inventors of the present application found that under this preferred condition, the carbon dioxide adsorbent provided by the present application has better adsorption of carbon dioxide and stronger stability of the carbon dioxide adsorbent when used for gas separation in acetylene / carbon dioxide mixed gas.

[0044] Preferably, the mixing reaction conditions include: the stirring speed is 300-1800 rpm, and more preferably 1400-1600 rpm, and the time is 2-4 h.

[0045] More preferably, the mixing reaction conditions include: the stirring speed is 1400-1600 rpm, the time is 2-4 h, and the temperature is 20-60℃.

[0046] Preferably, the mixing reaction is carried out under ultrasonic conditions, the frequency of the ultrasonic is 20-40 kHz, and the ultrasonic time is 4-24 h.

[0047] According to another preferred embodiment, the preparation method of the carbon dioxide adsorbent further comprises: before the mixing reaction of the present application is carried out, the porous carrier material is sequentially subjected to immersion washing and drying with solvent II to obtain a pretreated porous carrier material, and then the pretreated porous carrier material is used to participate in the mixing reaction.

[0048] The preparation method of the carbon dioxide adsorbent of the present application further comprises a conventional post-treatment method in the art. For example, the solvent in the system after the completion of the mixing reaction is removed by rotary evaporation, and in order to obtain a carbon dioxide adsorbent with better adsorption and stronger stability, the present application provides a preferred rotary evaporation method.

[0049] Preferably, the mixed solution containing the carbon dioxide adsorbent obtained after the completion of the mixing reaction is first subjected to rotary evaporation to remove 2 / 3 to 4 / 5 of the volume of solvent I under the conditions of 40°C and a vacuum degree of 60-80 kPa, and then the remaining solvent I is subjected to rotary evaporation under the conditions of 50°C and a vacuum degree of 10-40 kPa to obtain the carbon dioxide adsorbent.

[0050] Preferably, the solvent I and the solvent II are each independently selected from at least one of methanol, ethanol, acetone and water.

[0051] More preferably, the solvent I and the solvent II are each independently methanol and / or water.

[0052] The present application does not have special restrictions on the measurement method of the minimum desorption temperature of the carbon dioxide adsorbent, but in order to more accurately obtain the minimum desorption temperature of the carbon dioxide adsorbent provided by the present application, the present application preferably uses the following method for measurement, which comprises:

[0053] S1: First, the carbon dioxide adsorbent sample is heated to 800°C at a fixed heating rate using a thermal gravimetric analyzer, and the weight loss curve is recorded;

[0054] S2: The carbon dioxide adsorbent sample is added to the tray of the thermal gravimetric analyzer, and is raised to the starting temperature of the first platform as the desorption temperature at a fixed heating rate under a nitrogen atmosphere, and is kept for a fixed desorption time to stabilize the mass of the carbon dioxide adsorbent sample, to obtain the sample after desorption, and record the desorption temperature curve;

[0055] S3: Lower to room temperature at a fixed cooling rate, switch to a carbon dioxide atmosphere, keep for a fixed adsorption time, obtain the sample after adsorption, and record the adsorption temperature curve;

[0056] S4: repeating steps S2 and S3, except that each time the desorption temperature is lower than the previous desorption temperature by a fixed temperature gradient; and recording the adsorption temperature curve and the desorption temperature curve each time to form a lowest desorption temperature test curve;

[0057] S5: observing the recorded lowest desorption temperature test curve, and the lowest desorption temperature corresponding to the quality of the desorbed sample in step S2 is the lowest desorption temperature.

[0058] Preferably, the fixed heating rate in steps S1 and S2 is 1-20℃ / min, more preferably 5-10℃ / min.

[0059] Preferably, the fixed desorption time in step S2 is 10-60min, more preferably 10-20min.

[0060] Preferably, the fixed cooling rate in step S3 is 10-20℃ / min.

[0061] Preferably, the fixed adsorption time in step S3 is 10-60min, more preferably 30-60min.

[0062] Preferably, the fixed temperature gradient in step S4 is 5-20℃, more preferably 5-10℃.

[0063] The present application will be described in detail by way of examples. In the following examples, the raw materials are all commercially available unless otherwise specified, and the average pore size, specific surface area and pore volume of the porous carrier raw material provided by the present application are measured by a BET specific surface area and pore size micropore analyzer of BSD-PM2 type.

[0064] Macroporous resin I: purchased from Beijing Solaybao Technology Co., Ltd., with a trade name of HP20; the average pore size is 8.5nm, the specific surface area is 772m 2 / g, and the pore volume is 1.64mL / g.

[0065] Macroporous resin II: purchased from Mitsubishi Chemical Corporation, Japan, with a trade name of SP825L; the average pore size is 6.2nm, the specific surface area is 490m 2 / g, and the pore volume is 1.38mL / g.

[0066] Molecular sieve: purchased from Tianjin Nanhua Catalyst Co., Ltd., with a trade name of MCM-41; the average pore size is 3.1nm, the specific surface area is 1050m 2 / g, and the pore volume is 0.96mL / g.

[0067] Porous silica: purchased from Shanghai Aldrin Biochemical Technology Co., Ltd., average pore size of 12.05 nm, specific surface area of 168 m 2 / g, pore volume of 0.51 mL / g.

[0068] Activated carbon: purchased from Beijing Jindawei Activated Carbon Technology Co., Ltd., average pore size of 1.8 nm, specific surface area of 1270 m 2 / g, pore volume of 0.58 mL / g.

[0069] Metal-organic framework material: MIL-101(Cr) was synthesized according to the article "Synthesis of Metal-organic Framework MIL-101 with Acetate as Mineralizer [J]. Chemical Journal of Chinese Universities, 2012, 33(04): 668-672.", average pore size of 2.96 nm, specific surface area of 3480 m 2 / g, pore volume of 1.96 mL / g.

[0070] Magnesium oxide: nano-magnesium oxide, purchased from Shanghai Dibai Biological Technology Co., Ltd., average pore size of 16.86 nm, specific surface area of 90.9 m 2 / g, pore volume of 0.471 mL / g.

[0071] Polyethyleneimine: purchased from Shanghai Macklin Biochemical Technology Co., Ltd., weight average molecular weight of 600 Da.

[0072] Preparation Example 1

[0073] (1) Soak the porous carrier material in solvent II, wash away the hallucinogen and crosslinking agent remaining in the pores of the porous carrier material, and dry the washed porous carrier material in a 80°C vacuum drying oven. After cooling to room temperature, fill with nitrogen for standby;

[0074] The porous carrier material is macroporous resin I; the solvent II is methanol;

[0075] (2) Dissolve the amino active component in solvent I, and mix with the porous carrier material pretreated in step (1) for reaction (stirring at 1500 rpm for 3h) to obtain a mixed solution containing carbon dioxide adsorbent;

[0076] The solvent I is methanol, the amount is 50 mL, the amino active component is polyethyleneimine, the amount is 0.5 g, and the mass ratio of the amount of the porous carrier material to the amino active component is 1:1;

[0077] (3) Slowly evaporate 3 / 4 volume of solvent I in the mixed solution with a rotary evaporator at a vacuum degree of 70 kPa and a temperature of 40°C, adjust the vacuum degree to 10 kPa and the temperature to 50°C, and completely spin dry the solvent I to obtain the carbon dioxide adsorbent.

[0078] Preparation Example 2

[0079] (1) The porous carrier material is soaked in solvent II, and the residual hallucinogen and crosslinking agent in the pores of the porous carrier material are washed away. The washed porous carrier material is placed in a vacuum drying oven at 80°C and dried. After being cooled to room temperature, it is filled with nitrogen for standby;

[0080] The porous carrier material is molecular sieve; and the solvent II is ethanol.

[0081] (2) The amino active component is dissolved in solvent I, and the pretreated porous carrier material in step (1) is added for mixing reaction (stirring at 1500 rpm for 3 h) to obtain a mixed solution containing the carbon dioxide adsorbent.

[0082] The solvent I is ethanol, and the amount used is 50 mL. The amino active component is polyethyleneimine, and the amount used is 0.5 g. The mass ratio of the amount of the porous carrier material to the amount of the amino active component is 1:1.

[0083] (3) The mixed solution is slowly evaporated by a rotary evaporator at a vacuum degree of 70 kPa and a temperature of 40°C for 3 / 4 of the volume of solvent I. The vacuum degree is adjusted to 10 kPa, and the temperature is adjusted to 50°C. The solvent I is completely rotary dried to obtain the carbon dioxide adsorbent.

[0084] Preparation Example 3

[0085] (1) The porous carrier material is soaked in solvent II, and the residual hallucinogen and crosslinking agent in the pores of the porous carrier material are washed away. The washed porous carrier material is placed in a vacuum drying oven at 80°C and dried. After being cooled to room temperature, it is filled with nitrogen for standby;

[0086] The porous carrier material is porous silica; and the solvent II is acetone.

[0087] (2) The amino active component is dissolved in solvent I, and the pretreated porous carrier material in step (1) is added for mixing reaction (stirring at 1500 rpm for 3 h) to obtain a mixed solution containing the carbon dioxide adsorbent.

[0088] The solvent I is acetone, and the amount used is 50 mL. The amino active component is tetraethylenepentamine, and the amount used is 0.5 g. The mass ratio of the amount of the porous carrier material to the amount of the amino active component is 1:0.8.

[0089] (3) The mixed solution is slowly evaporated by a rotary evaporator at a vacuum degree of 70 kPa and a temperature of 40°C for 3 / 4 of the volume of solvent I. The vacuum degree is adjusted to 10 kPa, and the temperature is adjusted to 50°C. The solvent I is completely rotary dried to obtain the carbon dioxide adsorbent.

[0090] Preparation Example 4

[0091] (1) Soak the porous carrier material in solvent II, wash away the residual hallucinogen and crosslinking agent in the pores of the porous carrier material, and place the washed porous carrier material in a vacuum drying oven at 80°C for drying. After being cooled to room temperature, fill it with nitrogen for standby;

[0092] The porous carrier material is activated carbon; solvent II is water;

[0093] (2) Dissolve the amino active component in solvent I, and add the porous carrier material pretreated in step (1) for mixing reaction (stirring at 1500 rpm for 3 h) to obtain a mixed solution containing the carbon dioxide adsorbent;

[0094] Solvent I is water, and the amount used is 50 mL. The amino active component is diethanolamine, and the amount used is 0.5 g. The mass ratio of the amount of the porous carrier material to the amount of the amino active component is 1:1.2.

[0095] (3) Slowly evaporate 3 / 4 of the volume of solvent I from the mixed solution using a rotary evaporator at a vacuum degree of 70 kPa and a temperature of 40°C. Adjust the vacuum degree to 10 kPa and the temperature to 50°C, and completely spin dry the solvent I to obtain the carbon dioxide adsorbent.

[0096] Preparation Example 5

[0097] (1) Soak the porous carrier material in solvent II, wash away the residual hallucinogen and crosslinking agent in the pores of the porous carrier material, and place the washed porous carrier material in a vacuum drying oven at 80°C for drying. After being cooled to room temperature, fill it with nitrogen for standby;

[0098] The porous carrier material is a metal organic framework material; solvent II is methanol;

[0099] (2) Dissolve the amino active component in solvent I, and add the porous carrier material pretreated in step (1) for mixing reaction (stirring at 1500 rpm for 3 h) to obtain a mixed solution containing the carbon dioxide adsorbent;

[0100] Solvent I is methanol, and the amount used is 50 mL. The amino active component is polyethyleneimine, and the amount used is 0.5 g. The mass ratio of the amount of the porous carrier material to the amount of the amino active component is 1:1.2.

[0101] (3) Slowly evaporate 3 / 4 of the volume of solvent I from the mixed solution using a rotary evaporator at a vacuum degree of 70 kPa and a temperature of 40°C. Adjust the vacuum degree to 10 kPa and the temperature to 50°C, and completely spin dry the solvent I to obtain the carbon dioxide adsorbent.

[0102] Preparation Example 6

[0103] The procedure similar to that in Preparation Example 1 is adopted, except that the macroporous resin I is replaced with macroporous resin II of the same mass;

[0104] A carbon dioxide adsorbent is prepared.

[0105] Preparation Example 7

[0106] A similar procedure as in Preparation Example 1 is used, except that the amount of the porous carrier material is kept unchanged, and the amount of the amino active component is adjusted so that the mass ratio of the porous carrier material to the amino active component is 1:0.5.

[0107] A carbon dioxide adsorbent is prepared.

[0108] Comparative Preparation Example 1

[0109] A similar procedure as in Preparation Example 1 is used, except that the amino active component is replaced by diethylenetriamine of the same mass.

[0110] A carbon dioxide adsorbent is prepared.

[0111] Comparative Preparation Example 2

[0112] A similar procedure as in Preparation Example 1 is used, except that the porous carrier material is replaced by magnesium oxide of the same mass.

[0113] A carbon dioxide adsorbent is prepared.

[0114] Example 1

[0115] The carbon dioxide adsorbent prepared in the preparation example is subjected to carbon dioxide / acetylene (v:v = 1 / 99) breakthrough test, and the carbon dioxide adsorbent is contacted with acetylene / carbon dioxide mixed gas for adsorption.

[0116] The testing instrument is a Beifen SP-3420A chromatograph, the packed column used is a Shincarbon-ST packed column, the packing material is 60 / 80 mesh molecular sieve, the specification is 2.0 m x 2.2 mm I.D. x 3 mm O.D., the column phase temperature is 110°C, the sample injector temperature is 60°C, and the sampling interval is 14.995 min. The sample tube size used is D6*1.2, the carbon dioxide adsorbent is added to the sample tube, and the amount used is 300 mg, the gas used is carbon dioxide / acetylene (v:v = 1 / 99), and the gas flow rate is 3 ml / min.

[0117] The carbon dioxide adsorbent prepared by the technical solution provided in the present application has high carbon dioxide adsorption capacity when applied to acetylene / carbon dioxide mixed gas, and does not substantially adsorb acetylene, and has good selective adsorption. The adsorption effect of the carbon dioxide adsorbent in Preparation Example 1 is exemplarily provided. The results are shown in Table 1, and the breakthrough time is shown in Figure 1. Figure 2 Figure 2 ​It can be seen that acetylene first breaks through from the tail end of the adsorption column, and carbon dioxide comes out after 832 minutes, indicating that the carbon dioxide adsorbent prepared in Preparation Example 1 can efficiently remove trace amounts of carbon dioxide from acetylene.

[0118] Test Example 1

[0119] Thermogravimetric analysis (TGA) was performed on the carbon dioxide adsorbents obtained from each preparation example and the comparative preparation example (manufacturer: TA Instruments, USA, model TGA55) to determine the highest stable temperature. The results are shown in Table 1.

[0120] The present invention provides, by way of example, the thermogravimetric analysis curve of preparation example 1, as follows: Figure 3 As shown, through Figure 3 It can be seen that the first stage (room temperature to 100°C) is weight loss caused by the residual solvent in the carbon dioxide adsorbent and / or the adsorption of carbon dioxide and water from the air. The carbon dioxide adsorbent is stable from room temperature to 250°C. Above 250°C, a large amount of polyethyleneimine precipitates or decomposes, accompanied by the collapse of the macroporous resin skeleton. Therefore, the carbon dioxide adsorbent obtained in Preparation Example 1 can be used below 250°C, that is, its maximum stable temperature is 250°C.

[0121] Test Example 2

[0122] The lowest desorption temperature of the carbon dioxide adsorbents obtained in each preparation example and the comparative preparation example was determined using the following method. The results are shown in Table 1.

[0123] S1: First, the carbon dioxide adsorbent sample is heated to 800℃ using a thermogravimetric analyzer at a fixed heating rate, and the weight loss curve is recorded.

[0124] S2: Add the carbon dioxide adsorbent sample obtained in step S1 to the tray of the thermogravimetric analyzer. Under a nitrogen atmosphere, raise the temperature to the first plateau initial temperature of 100℃ at a fixed heating rate of 10℃ / min as the desorption temperature. Maintain a fixed desorption time of 30min to stabilize the mass of the carbon dioxide adsorbent sample, obtain the desorbed sample, and record the desorption temperature curve.

[0125] S3: Cool to room temperature at a fixed cooling rate of 10℃ / min, switch to carbon dioxide atmosphere, maintain a fixed adsorption time of 30min, obtain the adsorbed sample, and record the adsorption temperature curve;

[0126] S4: Repeat steps S2 and S3, but the desorption temperature is lower than the previous desorption temperature by a fixed temperature gradient (10℃) each time; and record the adsorption temperature curve and desorption temperature curve each time to form the lowest desorption temperature test curve.

[0127] S5: observing the recorded minimum desorption temperature test curve, the minimum desorption temperature corresponding to the condition that the carbon dioxide adsorbent sample is desorbed to the mass of the post-desorption sample described in step S2 is the minimum desorption temperature.

[0128] An exemplary minimum desorption temperature test curve of Preparation Example 1 is provided as shown in Figure 4 It can be seen from Figure 4 that the minimum desorption temperature corresponding to the condition that the carbon dioxide adsorbent sample is desorbed to the mass of the post-desorption sample described in step S2 is 70℃.

[0129] Test Example 3

[0130] The carbon dioxide adsorbent is characterized by a static volumetric adsorption method, and the carbon dioxide adsorption capacity is tested. The results are shown in Table 1.

[0131] An exemplary carbon dioxide adsorption curve of Preparation Example 1 is provided as shown in Figure 5 It can be seen from Figure 5 that the carbon dioxide adsorbent prepared in Preparation Example 1 has a strong force on carbon dioxide at a low pressure, and has a carbon dioxide adsorption capacity of 108 ml / g at normal pressure (101.3 kPa).

[0132] Test Example 4

[0133] The carbon dioxide adsorption-desorption cycle performance test is performed by a gravimetric method. The carbon dioxide adsorbent prepared by the technical solution provided in the present application has excellent cycle performance.

[0134] An exemplary carbon dioxide adsorption-desorption cycle curve of Preparation Example 1 is provided as shown in Figure 6 It can be seen from Figure 6 that after 10 times of carbon dioxide adsorption-desorption cycles, the carbon dioxide adsorption performance of the carbon dioxide adsorbent does not decrease significantly.

[0135] Table 1

[0136]

[0137] It can be seen from the results in Table 1 that the carbon dioxide adsorbent provided in the present application has a low desorption temperature and good stability. When the carbon dioxide adsorbent provided in the present application is applied to separate acetylene / carbon dioxide mixed gas, the carbon dioxide adsorbent has a strong force on carbon dioxide, not only has a large adsorption capacity, but also has excellent selectivity to carbon dioxide.

[0138] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including that each technical feature is combined in any other suitable manner. These simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A method of separating an acetylene / carbon dioxide mixture, characterized by, The method comprises: contacting an acetylene / carbon dioxide mixed gas with a carbon dioxide adsorbent to obtain a purified acetylene-containing gas; the concentration of carbon dioxide in the acetylene / carbon dioxide mixed gas is ≤1v%; the carbon dioxide adsorbent contains a porous carrier material and an amino active component, and the amino active component is loaded on the porous carrier material by grafting and / or impregnation; the preparation method of the carbon dioxide adsorbent comprises: mixing the porous carrier material with the amino active component in the presence of a solvent I to obtain the carbon dioxide adsorbent; the mass ratio of the porous carrier material to the amino active component is 1:0.8-1.5; The porous carrier material is provided by at least one selected from MCM-41, activated carbon, MIL-101(Cr); the average pore size of the porous carrier material is 1.8-15 nm, the specific surface area is 500-3500 m 2 / g, and the pore volume is 0.5-2 mL / g. the amino active component is provided by at least one selected from polyethyleneimine, tetraethylenepentamine and diethanolamine.

2. The method of claim 1, wherein, The conditions of the contacting adsorption include: temperature 0-100℃, pressure 0.1-1.25MPa.

3. The method of claim 1, wherein, The weight average molecular weight of the polyethyleneimine is 300-1800Da.

4. The method of any of claims 1-3, wherein, The carbon dioxide adsorption capacity of the carbon dioxide adsorbent is ≥92mL / g, the regeneration temperature is 40-150℃, and the maximum stable temperature is ≥180℃.

5. The method of claim 1, wherein, The conditions of the mixing reaction include: stirring speed 300-1800rpm, time 2-4h.

6. The method of claim 1, wherein, The solvent I is at least one selected from methanol, ethanol, acetone and water.

7. The method of claim 6, wherein, The solvent I is methanol and / or water.

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