Application of aluminum phosphate zeolite in separation of ethane and ethylene

Abstract

The invention belongs to the technical field of gas separation, and particularly relates to application of aluminum phosphate zeolite in separation of ethane and ethylene. The aluminum phosphate zeolite has a regular ultra-microporous framework structure. Pore channels can generate an optimal space confinement effect, and efficient ethane / ethylene adsorption separation is realized through a thermodynamic and dynamic synergistic mechanism. Specifically, the aluminum phosphate zeolite shows excellent ethane adsorption capacity of 52.95 cm < 3 > / g under the conditions of 298 K and 1 bar, and has higher ethane / ethylene selectivity of 2.12. Kinetic studies show that the diffusion rate of ethane in the zeolite is significantly higher than that of ethylene. A breakthrough experiment proves that the material can realize complete separation of ethane / ethylene mixed gas, and a cycle test shows that the material has excellent regeneration performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of gas separation, and particularly relates to application of aluminum phosphate zeolite in ethane ethylene separation. BACKGROUND

[0002] Ethylene (C2H4) is an important organic raw material in the field of petrochemical industry, and plays an irreplaceable role in the production of various chemicals and polymers. At present, ethane (C2H6) dehydrogenation is one of the main process routes for preparing ethylene. This process will cause a certain amount of ethane to remain in the product, which needs to be separated and purified to obtain polymer-grade purity (≥ 99.95%) ethylene. However, due to the high similarity of the physical properties of ethane and ethylene, the molecular sizes of the two are similar (ethylene: 3.28 Å × 4.18 Å × 4.84 Å; ethane: 4.08 Å × 3.81 Å × 4.82 Å) and the boiling points are close (ethylene: 169.4 K; ethane: 184.5 K), the separation process is extremely challenging.

[0003] In order to obtain polymer-grade ethylene product, the petrochemical industry generally uses low-temperature distillation technology for ethane / ethylene separation. However, this process not only has a complex process, but also has very high energy consumption, which significantly affects the production efficiency and economy of ethylene. Pressure swing adsorption (PSA) technology has great potential in the field of ethane / ethylene separation due to its low energy consumption, simple operation and environmental friendliness. The key to the successful application of PSA technology lies in the development of high-efficiency and stable adsorbents. Therefore, the development of economically feasible, high-performance and durable adsorbents is crucial to ensure the economic reliability and practical applicability of the technology.

[0004] With the rapid development of technology, a variety of porous materials have emerged, all of which have certain selectivity and adsorption capacity. In contrast, zeolites, as traditional inorganic porous materials, have become irreplaceable key materials in many industrial fields due to their unique crystal structure, excellent thermal and chemical stability, and outstanding industrial application value. Most commercial zeolites have stronger adsorption capacity for ethylene than for ethane, which requires an additional desorption process to obtain high-purity ethylene. Pure silicon zeolites have low polarity on the framework surface due to the lack of metal cations in the structure, which can preferentially adsorb ethane, thereby simplifying the separation process and reducing energy consumption.

[0005] Currently, in the reported research on ethane-selective adsorption zeolites, researchers mainly focus on the explanation of the thermodynamic separation mechanism. In fact, the separation performance of adsorbents is influenced by both thermodynamic and kinetic factors. Kinetic factors are related to the adsorption rate and directly affect the efficiency of the separation process. Previous studies have shown that materials with suitable pore structures and strong interaction sites can effectively achieve the thermodynamic separation of ethane / ethylene, but there is little research on their kinetics. Based on the unique pore structure and surface properties of aluminum phosphate zeolite, it is expected to bring significant kinetic differences to the ethane / ethylene separation process. SUMMARY

[0006] In view of the problems in the prior art, the application provides application of aluminum phosphate zeolite in ethane ethylene separation. The aluminum phosphate zeolite has a regular ultramicroporous framework structure, and the pore channel can generate an optimal space confinement effect, and can realize efficient adsorption separation of ethane / ethylene based on a synergistic mechanism of thermodynamics and kinetics.

[0007] The application is realized by the following technical scheme: Application of aluminum phosphate zeolite in ethane ethylene separation.

[0008] Further, the preparation method of the aluminum phosphate zeolite comprises the following steps: aluminum isopropoxide (1.73 g), phosphoric acid (0.97 g) and distilled water (7.33 g) are added into a 25 mL polytetrafluoroethylene-lined reaction kettle, stirring for 2 hours to ensure complete homogenization, then adding morpholine (0.92 g) and continuing to stir for 1 hour, and finally adding hydrofluoric acid (0.21 g) and stirring for 6 hours until the reactants are completely dissolved. The reaction mixture is sealed and heated in a 463 K oven for 10 days. After taking out, deionized water is used as a solvent, and centrifugation is performed at a speed of 11,000 rpm for 3 times (3 minutes each time), and the supernatant is discarded to obtain white crystals, which are dried to obtain white powder. The final product is calcined in a muffle furnace at 923 K under air atmosphere for 7 hours to obtain the target product aluminum phosphate zeolite.

[0009] Further, the BET specific surface area of the aluminum phosphate zeolite is 880 m 2 / g, the total pore volume is 0.25 cm 3 / g, and the average pore size is 0.56 nm.

[0010] Further, the aluminum phosphate zeolite has low-polarity surface channels and an ultramicroporous framework structure formed by alternating phosphorus-oxygen and aluminum-oxygen tetrahedra.

[0011] Further, the aluminum phosphate zeolite has a high ethane adsorption capacity of 52.95 cm 3 / g and an ethane / ethylene adsorption selectivity of 2.12.

[0012] Further, the aluminum phosphate zeolite can be recycled and regenerated when ethylene ethane separation is performed.

[0013] Further, the aluminum phosphate zeolite realizes efficient adsorption separation of ethane / ethylene through a synergistic mechanism of thermodynamics and kinetics.

[0014] The beneficial technical effects of the application are as follows: The present application focuses on an aluminophosphate zeolite, a microporous adsorbent material with a regular super-microporous framework structure. Its pore channels can produce an optimal spatial confinement effect, realizing the efficient adsorption separation of ethane / ethylene through a synergistic mechanism of thermodynamics and kinetics.

[0015] Specifically: the aluminophosphate zeolite exhibits an excellent ethane adsorption capacity of 52.95 cm 3 / g at 298 K and 1 bar, while having a higher ethane / ethylene selectivity of 2.12. Kinetic studies show that the diffusion rate of ethane in the zeolite is significantly higher than that of ethylene. Breakthrough experiments prove that the material can realize the complete separation of ethane / ethylene mixed gas, and the cyclic test shows that it has excellent regeneration performance. Pressure swing adsorption (PSA) simulation further shows that the aluminophosphate zeolite is a promising candidate material for selective separation of ethane / ethylene, and has broad application prospects in the ethylene purification industry. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 . (a) PXRD pattern of the aluminophosphate zeolite; (b) N2 adsorption-desorption isotherm at 77 K; (c) DFT pore size distribution; (d) TGA curve.

[0017] Figure 2 . (a-c) Adsorption / desorption isotherms of the aluminophosphate zeolite for ethane and ethylene; (d) IAST selectivity of the aluminophosphate zeolite for ethane / ethylene mixture at 298 K; (e) Comparison of IAST selectivity of the aluminophosphate zeolite for ethane / ethylene with ethane adsorption capacity with reported zeolites; (f) Adsorption heat of the aluminophosphate zeolite for ethane and ethylene Q st ).

[0018] Figure 3 . IAST selectivity of the aluminophosphate zeolite for C2H6 / C2H4 mixture at 273 K and 313 K.

[0019] Figure 4 . Adsorption kinetic curves of ethane and ethylene at 273 K (a), 298 K (b) and 313 K (c) (inlet flow rate 100 mbar / min); desorption kinetic curves at 273 K (d), 298 K (e) and 313 K (f).

[0020] Figure 5 . Initial state of C2H6 / C2H4 (50 / 50 volume ratio) mixture through molecular dynamics (MD) simulation of the aluminophosphate zeolite.

[0021] Figure 6 . Mean square displacement (MSD) of C2H6 and C2H4 in the aluminophosphate zeolite obtained by molecular dynamics (MD) simulation as a function of time.

[0022] Figure 7 . 298 K and 1 bar, center-of-mass probability distribution isopleths of C2H6(a) and C2H4(b) in the mixture; (c) and (d) the most stable configurations of C2H6 and C2H4 and the adsorption energies (hydrogen, carbon, oxygen, aluminum, phosphorus atoms are represented by white, gray, red, pink, yellow, respectively).

[0023] Figure 8 . (a) C2H6 / C2H4(50 / 50, v / v) and (b) C2H6 / C2H4(10 / 90, v / v) breakthrough curves on aluminum phosphate zeolite; (c) C2H6 adsorption cycle regeneration experiment; (d) C2H6 / C2H4(50 / 50, v / v) mixed gas cycle test at a flow rate of 15 mL / min.

[0024] Figure 9 . Detailed calculation process of olefin yield based on breakthrough curve.

[0025] Figure 10 . Comparison of olefin (99.9% purity) yield of C2H6 / C2H4(50 / 50 v / v) mixture on aluminum phosphate zeolite and reported materials.

[0026] Figure 11 . (a) C2H6 / C2H4(50 / 50, v / v) breakthrough curve on aluminum phosphate zeolite at 298 K and simulation results; using C2H6 / C2H4(50 / 50, v / v) as raw gas, the purity, recovery rate and yield of C2H4 on aluminum phosphate zeolite under different (b) vacuum pressure, (c) feed flow rate, (d) adsorption time were simulated by PSA.

[0027] Figure 12 . Schematic diagram of the structure of aluminum phosphate zeolite and the separation of ethane and ethylene, the topological structure with regular size pores is suitable for rapid adsorption of ethane molecules, and the cage structure with low polarity surface shows extremely high ethane adsorption capacity. Green, gray and red nodes in the figure represent phosphorus, aluminum and oxygen atoms in the framework, blue and yellow spheres correspond to carbon atoms in ethane and ethylene, and white spheres represent hydrogen atoms. DETAILED DESCRIPTION

[0028] Example 1 Preparation of aluminum phosphate zeolite Aluminum isopropoxide (1.73 g), phosphoric acid (0.97 g), and distilled water (7.33 g) were added to a 25 mL polytetrafluoroethylene-lined reactor. After stirring for 2 hours to ensure complete homogenization, morpholine (0.92 g) was added, and stirring continued for 1 hour. Finally, hydrofluoric acid (0.21 g) was added, and stirring continued for 6 hours until the reactants were completely dissolved. The reaction mixture was sealed and heated in a 463 K oven for 10 days. After removal, the mixture was centrifuged three times (3 minutes each time) at 11,000 rpm using deionized water as a solvent. The supernatant was discarded to obtain white crystals, which were then dried to obtain a white powder. The final product was calcined in a muffle furnace at 923 K for 7 hours under air atmosphere to obtain the target product, aluminum phosphate zeolite.

[0029] 1. Basic Characterization: The PXRD pattern of the aluminum phosphate zeolite prepared in Example 1 is basically consistent with the standard pattern in terms of the position and intensity of the characteristic diffraction peaks, indicating that the sample was successfully synthesized. Figure 1 a) The N2 adsorption-desorption isotherm at 77 K shows that the BET specific surface area of ​​aluminum phosphate zeolite is 880 m² / g, and the total pore volume is 0.25 cm³. 3 / g. For example... Figure 1 As clearly shown in b, under relatively low pressure, the presence of micropores leads to a strong interaction between the adsorbate and the pore walls, a typical characteristic of type I isotherms. The average pore size of the sample is 0.56 nm. Figure 1 c). Thermogravimetric analysis was used to assess the thermal stability of the samples. When heated at a rate of 10 K / min, the samples exhibited significant mass loss near 923 K, which was a result of the combined removal of bound water and template agent. Figure 1 d).

[0030] 2. Ethane / ethylene equilibrium separation performance is shown in 2a-c. Single-component adsorption isotherms for ethane and ethylene were measured in the temperature range of 273 K to 313 K and the pressure range of 1 bar. At 273 K, 298 K, and 313 K, aluminum phosphate zeolite exhibited significantly differentiated preferential adsorption behavior, preferentially adsorbing ethane rather than ethylene. This selectivity was particularly pronounced under low-pressure conditions, indicating a high-affinity interaction between aluminum phosphate zeolite and ethane. Specifically, at 298 K and 1 bar, the ethane adsorption capacity of aluminum phosphate zeolite reached 52.95 cm⁻¹. 3 / g. For example... Figure 2 As shown in e, this performance is comparable to the highest ethane adsorption capacity reported in the current literature for zeolite-based adsorbents, including pure silica Beta zeolite (55.55 cm⁻¹). 3 / g), Si-CHA(F) (55.55 cm 3 / g), Si-BEA(F) (50.84 cm 3ZSM-11 (1500) (49.84 cm 3 Si-MFI (F) (43.23 cm 3 TS-1 (42.11 cm 3 Silicalite-1 (39.64 cm 3 DDR (21.73 cm 3 In addition, the adsorption capacity of the aluminum phosphate zeolite is superior to some of the porous materials (see Table 1).

[0031] Table 1. Comparison with other C2H6-selective adsorbents at 298 K and 1 bar.

[0032]

[0033] To evaluate the separation potential of the aluminum phosphate zeolite for ethane / ethylene mixtures, the selectivity of C2H6 / C2H4 was calculated at different ratios (50 / 50 and 10 / 90 v / v) using the IAST method. As shown in Figure 2 d and 3, the C2H6 / C2H4 adsorption selectivity of the aluminum phosphate zeolite is 2.12 / 2.13 (50 / 50 and 10 / 90 v / v) at 298 K and 1 bar. This result indicates that its adsorption selectivity is superior to most ethane-selective zeolite adsorbents, such as Si-CHA(F) (2.09), TS-1 (2.07), Si-MFI(F) (1.98), ZSM-11(1500) (1.73), Silicalite-1 (1.72), pure-silica Beta zeolite (1.66), and DDR (1.49) (see Table 1). Figure 2

[0034] As shown in Figure 2 f, the zero-coverage adsorption heat of ethane on the aluminum phosphate zeolite is as high as 34.78 kJ / mol, which exceeds most of the reported ethane-selective zeolite adsorbents (Table 2). Q st 0 Q st With the increase of ethane adsorption amount, the adsorption energy decreases, which can be attributed to the rapid saturation of high-affinity sites at low coverage and the involvement of remaining weak sites in subsequent adsorption. In contrast, the adsorption energy of C2H4 at different adsorption sites changes less, so Q st the fluctuation is not obvious (<1 kJ / mol). These data also confirm the above-mentioned selectivity calculation results.

[0035] ​​Table 2. Initial heat of adsorption of C2H6on several reported C2H6-selective zeolite adsorbents Q st 0 ) Comparative analysis Sample Q stC2H6 0 (kJ / mol)]]> ​ Aluminophosphate zeolite 34.78 Silicalite-1 30.84 TS-1 29.22 ZSM-11 (1500) 27.10 DDR 25.00 Si-BEA (F) 23.50 Pure silica Beta 23.04 3. Adsorption kinetics and desorption behavior Considering the match between the kinetic diameters of gas molecules and the pore size of the material, the time-dependent adsorption kinetics curves of the aluminum phosphate zeolite were further studied at temperatures ranging from 273 to 313 K and a pressure of 1 bar. As shown in Figure 4 a, b, and c, the adsorption rate of ethane on the aluminum phosphate zeolite was significantly faster than that of ethylene at all studied temperatures. As the temperature increased, the time difference between ethane and ethylene reaching adsorption equilibrium gradually increased: at 313 K, ethane only needed 10.9 minutes to reach equilibrium, while ethylene needed 14.5 minutes. This indicates that the diffusion rate of ethane in the material is significantly faster than that of ethylene, mainly due to the highly regular pore structure of the aluminum phosphate zeolite and the stronger interaction between the low-polarity pore surface and ethane molecules. Notably, such a difference in ethane / ethylene diffusion rates has not been reported in the field of zeolite-based adsorption separation. By calculating the kinetic selectivity ratio [D o (C2H6) / D o (C2H4)], it reached 1.59 at 298 K (Table 3), demonstrating that the gas adsorption process is affected by kinetic adsorption effects.

[0036] As shown in Figure 4 d, e, and f, the aluminum phosphate zeolite can achieve complete desorption of ethane and ethylene within about 12 minutes at three temperatures. Although the equilibrium desorption time of ethane at 273 K is significantly longer than that of ethylene, this is due to the stronger affinity of the material for ethane molecules, consistent with the previous adsorption data. This efficient desorption can be achieved through vacuum operation alone, without the need for additional heating treatment, significantly enhancing its potential for widespread application in industrial PSA technology.

[0037] Table 3. Summary of equilibrium adsorption capacity and kinetic C2H6 / C2H4 selectivity of aluminum phosphate zeolite

[0038] The dynamic adsorption characteristics of ethane / ethylene in the aluminum phosphate zeolite were studied through molecular dynamics (MD) simulation. As shown in Figure 5 , the initial stage of MD simulation, the ethane / ethylene (50 / 50 v / v) mixture diffused into the aluminum phosphate zeolite structure from both sides. Figure 6 shows the mean square displacement (MSD) values of the two gas molecules change with the increase of diffusion time, and within 0-1000 ps, the MSD value of ethane is always higher than that of ethylene. The diffusion constants measured are D(C2H6)=13.559×10-3 nm 2 / ps and D(C2H4) = 11.496 x 10 -3 nm 2 / ps, indicating that the diffusion rate of ethane in the aluminum phosphate zeolite is significantly faster than that of ethylene.

[0039] 4. GCMC simulation To further explore the separation mechanism of aluminum phosphate zeolite for ethane / ethylene, GCMC simulation was performed. Figure 7 a-b show the equilibrium distribution of C2H6 and C2H4 in the structure of aluminum phosphate zeolite at 298 K and 1 bar. C2H6 molecules tend to occupy the inside of the channel, while C2H4 molecules are also adsorbed near the center of the hole, but the center of mass distribution density is significantly lower than that of C2H6. Further calculation of the adsorption heat under the condition of infinite dilution and determination of the adsorption site: as shown in c-d, the average distance between the six hydrogen atoms of C2H6 molecules and the skeleton oxygen atoms is 3.106-3.378 Å, while the distance between the four hydrogen atoms of C2H4 molecules and the skeleton is slightly farther (3.223-3.865 Å). The calculated binding energy is C2H6 37.30 kJ / mol, C2H4 35.60 kJ / mol, which is highly consistent with the experimental measured equivalent adsorption heat (C2H6: 34.78 kJ / mol; C2H4: 25.09 kJ / mol), confirming that the low-polarity channel has the optimal binding site for C2H6, highlighting its excellent recognition ability. Figure 7

[0040] 5. Breakthrough experiment and stability At 298 K and 1 bar, dynamic breakthrough experiments were performed on C2H6 / C2H4 (50 / 50 and 10 / 90 v / v) mixed gas at a flow rate of 10-20 mL / min. As shown in Figure 8 a, for 50 / 50 mixed gas: the co-adsorption time is 11.96 minutes and 6.04 minutes at a flow rate of 10 mL / min and 15 mL / min, respectively, and the weakly adsorbed component C2H4 is first released to produce a high-purity gas stream, and C2H6 breakthroughs after a certain period of time (separation time is 2.90 minutes and 4.83 minutes, respectively). The 10 / 90 mixed gas also shows similar rules ( Figure 8 b): the co-adsorption time is 10.32 minutes and 7.66 minutes at a flow rate of 10 mL / min and 15 mL / min, respectively, and the separation time is 6.26 minutes and 2.93 minutes, respectively (see Table 4). The steep breakthrough curve indicates that the mass transfer rate in the sample is high, which is beneficial to rapid equilibrium, proving that the aluminum phosphate zeolite has excellent adsorption performance and separation efficiency under the test conditions.

[0041] Table 4. Gas composition, flow rate, co-adsorption time and separation time of aluminum phosphate zeolite in breakthrough experiment ​

[0042] Adsorption repeatability was evaluated through cyclic experiments: such as Figure 8 As shown in c, after ten cycles, the adsorption capacity of C2H6 remained stable at ~52 cm⁻¹. 3 / g, fully demonstrating its excellent reproducibility. Furthermore, ten cycles of breakthrough experiments were conducted on aluminum phosphate zeolite. The results clearly show that the effluent time interval between C2H6 and C2H4 remained consistent throughout the entire cycle. This stable effluent time interval strongly demonstrates the excellent practical regeneration performance of aluminum phosphate zeolite. Figure 8 d). According to the breakthrough experiment results, high-purity C2H4 (99.9%) can be directly obtained within the time interval t0-t1, with a yield as high as 11.91 L / kg ( Figure 9 This value surpasses that of most previously reported materials, such as TS-1 (11.50 L / kg), Silicalite-1 (9.80 L / kg), Cu(Qc)2 (4.34 L / kg), MUF-15 (6.60 L / kg), MAF-49 (6.20 L / kg), PCN-250 (10.00 L / kg), etc. Figure 10 ).

[0043] 6. PSA simulation Based on breakthrough curve data of aluminum phosphate zeolite, a PSA simulation was established to evaluate its actual separation performance for C2H6 / C2H4 (50 / 50, v / v) mixtures. Figure 11 As shown in Figure a, the simulated breakthrough experiment results are in high agreement with the actual experiment (simulation parameters are detailed in Table 5). Figure 11 b shows that as the vacuum pressure increases, the recovery rate and yield increase, but the product purity decreases from 94.99% to 77.09%, indicating that the vacuum pressure has a significant impact on the product purity. The decrease in purity is because a lower vacuum pressure allows the adsorbent to optimize bed utilization in the PSA cycle and enhances the competitive adsorption of C2H6 and C2H4. By further optimizing the vacuum pressure, adsorption time, and feed flow rate, the optimal product purity (86.04%), recovery rate (71.82%), and yield (2.17 mol / h / kg) were determined to be achieved at an adsorption time of 300 seconds and a feed flow rate of 0.01187 mmol / s, demonstrating that aluminum phosphate zeolite has broad application prospects in the field of ethane / ethylene separation.

[0044] Table 5. Parameter settings for a six-step pressure swing adsorption (PSA) simulation in a dual-bed environment. Description Value Unit Adsorbent bed height 0.15 m Adsorbent bed inner diameter 0.70 cm Inter-particle porosity 0.39 m 3 void / m 3 bed]]> Intra-particle porosity 0.41 m 3 void / m 3 bead]]> Adsorbent bulk density 661.00 kg / m 3 ]] Adsorbent particle radius 5E-5 m Adsorbent shape factor 1.00 n / a Constant mass transfer coefficient (C2H4) 0.80 1 / s Constant mass transfer coefficient (C2H6) 1.00 1 / s Conclusion: See Figure 12, phosphorus and aluminum oxytetrahedra alternately constitute low-polarity surface channels, providing optimal adsorption sites for ethane molecules and significantly enhancing the adsorption process. The results show that the aluminum phosphate zeolite has a high ethane adsorption capacity (52.95 cm 3 / g) and good ethane / ethylene adsorption selectivity (2.12). Thanks to the synergistic effect of thermodynamic and kinetic separation mechanisms, breakthrough experiments demonstrate that the aluminum phosphate zeolite exhibits excellent separation performance for ethane / ethylene mixtures under dynamic conditions. Notably, the ethylene yield of this material reaches 11.91 L / kg, which is superior to most reported adsorbents. PSA simulation shows that the ethylene purity can be increased from 50% to 86.04% and the recovery rate reaches 71.82% through single-step enrichment of the aluminum phosphate zeolite. These findings prove that the aluminum phosphate zeolite has great potential for selectively capturing ethane in ethane / ethylene mixed gas, providing an innovative solution for industrial purification and separation technology.

Claims

1. An application of aluminum phosphate zeolite in the separation of ethane and ethylene mixed gases.

2. The application according to claim 1, characterized in that, The aluminum phosphate zeolite has an electrically neutral framework composed of alternating phosphorus-oxygen tetrahedra and aluminum-oxygen tetrahedra, low-polarity surface channels, and a regular ultraporous structure.

3. The application according to claim 1, characterized in that, The aluminum phosphate zeolite has a BET specific surface area of ​​880 m² / g, a total pore volume of 0.25 cm³ / g, and an average pore size of 0.56 nm.

4. The application according to claim 1, characterized in that, The aluminum phosphate zeolite exhibits an adsorption capacity of 52.95 cm³ / g for ethane at 298 K and 1 bar.

5. The application according to claim 1, characterized in that, The aluminum phosphate zeolite exhibits a C2H6 / C2H4 adsorption selectivity of 2.12 at a volume ratio of 50 / 50 and a C2H6 / C2H4 adsorption selectivity of 2.13 at a volume ratio of 10 / 90 under conditions of 298 K and 1 bar.

6. The application according to claim 1, characterized in that, The aluminum phosphate zeolite achieves the adsorption and separation of ethane and ethylene based on a synergistic mechanism of thermodynamics and kinetics, wherein the diffusion rate of ethane within the zeolite is higher than that of ethylene.

7. An adsorbent for the separation of ethylene and ethane, characterized in that, The adsorbent is composed of aluminum phosphate zeolite as described in any one of claims 1-6.

8. A method for preparing aluminum phosphate zeolite as described in any one of claims 1-6, characterized in that, The process includes the following steps: 1.73 g of aluminum isopropoxide, 0.97 g of phosphoric acid, and 7.33 g of distilled water were added to a 25 mL polytetrafluoroethylene-lined reactor. After stirring for 2 hours to ensure complete homogenization, 0.92 g of morpholine was added and stirring was continued for 1 hour. Finally, 0.21 g of hydrofluoric acid was added and stirring was continued for 6 hours until the reactants were completely dissolved. The reaction mixture was sealed and heated in an oven at 463 K for 10 days. After removal, deionized water was used as the solvent, and the mixture was centrifuged three times at 11,000 rpm for 3 minutes each time. The supernatant was discarded to obtain white crystals, which were dried to obtain a white powder. The final product was calcined in a muffle furnace at 923 K for 7 hours under air atmosphere to obtain the target product, aluminum phosphate zeolite.

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