Preparation method of coal phenol oil-based adsorbing material and coal phenol oil-based carbon adsorbing material

Abstract

The present application belongs to the technical field of gas separation and purification, and particularly relates to a preparation method of a coal phenol oil-based adsorption material and a coal phenol oil-based carbon adsorption material. The present application uses coal phenol oil as raw material, extracts phenolic substances in the coal phenol oil by using KOH solution, then adds aldehyde substances for polymerization, and then prepares a porous adsorption material by high-temperature carbonization of the polymer. The present application does not need to use acid liquor to replace the phenolic substances, reduces the generation of waste acid and waste salt, and KOH can not only be used as an alkaline catalyst to catalyze the polymerization of the phenolic substances and the aldehyde substances, but also can be used as a pore-forming agent, so that the porous adsorption material generated after high-temperature carbonization has moderate pores and concentrated distribution. The present application couples phenol oil extraction, polymer synthesis and high-temperature carbonization into an integrated whole, effectively reduces the use of alkaline reagents, and the prepared adsorption material has strong selectivity to methane and large adsorption capacity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of gas separation and purification, and particularly relates to a preparation method of a coal phenol oil-based adsorption material and a coal phenol oil-based carbon adsorption material. BACKGROUND

[0002] Coal tar is a liquid product after dry distillation of coal, and coal phenol oil is an important fraction of coal tar and is a mixture with very complex components. The main chemical component of coal phenol oil is phenolic compounds, and it also contains nitrogen-containing bases, neutral oil and a small amount of sulfur-containing compounds. Phenolic substances will produce a large amount of wastewater and waste salt during the extraction process, causing pollution, and the separation and purification of phenolic substances are also relatively difficult. How to use it with high added value is a problem to be solved.

[0003] Coalbed methane, as unconventional natural gas stored in coal seams, is mainly composed of methane (CH4). With the development of low-concentration coalbed methane (CH4 concentration < 30%) and shale gas resources, high content of nitrogen (N2) will significantly reduce the heating value of the gas and increase the transportation cost. Therefore, efficient separation of CH4 / N2 is the core challenge of coalbed methane resource utilization. However, CH4 and N2 have similar kinetic diameters (CH4: 3.8 Å, N2: 3.6 Å) and small differences in polarizability, and are both nonpolar molecules, which leads to insufficient selectivity of traditional adsorbents. At present, pressure swing adsorption (PSA) is the most promising process for methane enrichment and concentration, and the core of which is the adsorbent. Carbon-based materials have become a research hotspot for CH4 / N2 separation due to their adjustable pore structure, stable structural properties and low cost. However, in the field of coalbed methane separation, existing adsorption materials face many technical bottlenecks. On the one hand, it is difficult to effectively separate CH4 / N2 mixed gas in low-concentration coalbed methane. On the other hand, although some materials can separate N2 in coalbed methane, they rely on special separation devices and specific adsorption materials. These materials not only require the use of multiple organic solvents for preparation, but also have difficulties in obtaining raw materials, high cost, and special preparation process, which makes it extremely difficult to promote industrialization.

[0004] The coal tar oil-based adsorbent material can be prepared by using the coal tar oil and the phenolic resin, and the coal tar oil-based adsorbent material can be further converted into the coal tar oil-based adsorbent material by high-temperature carbonization, so that the high-value utilization of the coal tar oil can be realized, and the selection range of the adsorbent material for the coal bed gas extraction and separation can be expanded. However, there are few studies on the preparation of the coal tar oil-based adsorbent material by using the coal tar oil. In general, there are mainly the following problems. (1) The pollution of waste liquid generated by extraction of phenolic substances and the energy consumption of separation and purification. The extraction rate of the phenolic substances can be improved by controlling the rectification temperature and combining with chemical conversion in the industrial extraction of the phenolic substances from the phenolic coal tar, but the acid and alkali extraction is still used, and a large amount of waste liquid still needs subsequent treatment. In addition, the separation and purification of the phenolic substances also causes energy consumption. (2) The problems in the resin synthesis process. For example, the acid catalyst and the emulsifier are needed in the synthesis of the linear phenolic (Novolac) resin in the preparation method of the activated carbon adsorbent in JP7061640B2, and the synthesis of the composite resin also increases the complexity of the process. The acid or alkali catalyst is needed in the resin synthesis, the acid catalyst is more likely to corrode the equipment, the resin needs to be neutralized by adding alkali, and other additives such as the surfactant, the initiator and the modified monomer also need to be added in order to meet the performance or other requirements. In addition, the waste salt or other additives also need to be removed and treated after the resin synthesis, which increases the complexity of the process, the energy consumption and the environmental protection cost. (3) The problem of the large amount of KOH alkali used in the carbon material. For example, the mass ratio of the carbonized material to the alkali is 1: (0.5-5) in the preparation of the composite phenolic resin-based activated carbon in CN106115693B, and the large amount of alkali used increases the resource consumption, causes environmental pollution and affects the service life of the equipment.

[0005] In summary, it is of great significance to develop a carbon material with low-cost industrial byproducts as raw materials, high adsorption capacity and high selectivity, and the process needs to have the characteristics of environmental friendliness, low wastewater generation and low alkali consumption, so as to meet the industrialization needs of the efficient purification of the coal bed gas. SUMMARY

[0006] In view of the above problems, the application provides an innovative solution. The phenolic substances in the coal tar oil are extracted and utilized to synthesize the resin, and then the coal tar oil resin-based carbon adsorbent material is obtained by carbonization.

[0007] In order to achieve the above purpose, the application adopts the following technical scheme.

[0008] A preparation method of a coal tar oil-based carbon adsorbent material, comprising the following steps:

[0009] 1) A certain amount of alkali solution and coal tar oil are mixed according to a certain volume ratio, stirred, and then separated into layers, and the lower liquid phase is taken for standby use;

[0010] 2) add aldehyde compound into methanol solvent, then add a certain amount of ammonia water to dissolve, to obtain a clear solution;

[0011] 3) mix the lower liquid phase obtained in step 1) and the clear solution obtained in step 2), stir to mix them evenly, then solidify at 80℃ for 24h to obtain a resin-like intermediate;

[0012] 4) transfer the resin-like intermediate obtained in step 3) to a tube furnace, perform high-temperature carbonization treatment under an inert atmosphere, after carbonization, cool to room temperature to obtain a solid material;

[0013] 5) acid wash, filter and dry the solid material obtained in step 4) to obtain the said cresylic oil-based carbon adsorption material.

[0014] Preferably, in step 1), the alkali solution is KOH solution, the concentration range is 0.1 mol / L-1.0 mol / L.

[0015] Preferably, in step 1), the alkali solution and cresylic oil are mixed in a volume ratio of 2-10.

[0016] Preferably, in step 2), the aldehyde compound includes but is not limited to terephthaldehyde and other aldehyde substances.

[0017] Preferably, in step 2), the aldehyde compound is added to the methanol solvent to prepare an aldehyde methanol solution with a concentration range of 0.1 mol / L-1 mol / L.

[0018] Preferably, in step 2), the volume ratio of ammonia water to methanol is in the range of 0.01-0.05.

[0019] Preferably, in step 3), the volume ratio of the lower liquid phase to the clear solution is 0.1-1.0.

[0020] Preferably, in step 4), the inert atmosphere is nitrogen, argon or helium, and the high-temperature carbonization treatment temperature is 600 ℃-800 ℃.

[0021] A cresylic oil-based carbon adsorption material prepared by the above preparation method, characterized in that it is suitable for coalbed methane separation and purification field. In particular, it is suitable for separating CH4 / N2 mixed gas in coalbed methane by adsorption method, and the optimal adsorption condition is 0-30 ℃ and the pressure is 0.1 MPa-1 MPa.

[0022] The preparation method of the coal cresol oil-based carbon adsorption material of the present application combines the extraction of phenolic substances, the synthesis of resins and the carbonization process, while taking into account the extraction efficiency, catalytic synthesis of resins and pore making of carbon materials, greatly reducing the amount of alkali used and the generation of wastewater, and the process is more green and environmentally friendly. The pore size distribution of the material is uniform, the adsorption amount of methane is 21.14-31.41 cm 3 / g (298 K, 100 kPa), the specific surface area is 501.52-1115.09 m 2 / g, the micropore ratio is more than 80%, and the IAST selectivity of CH4 / N2 is 5.74-7.97. In addition, the high value-added utilization of coal cresol oil improves economic benefits and reduces environmental pollution. The application of the coal cresol oil-based carbon adsorption material to the coalbed methane separation and purification process can efficiently realize the enrichment and purification of low-concentration methane, effectively break through the barriers of traditional technology, and has economic feasibility and environmental friendliness, opening up a new path for efficient utilization of coalbed methane.

[0023] Compared with the existing preparation method of adsorption material, the coal cresol oil-based carbon adsorption material provided by the present application has the following advantages:

[0024] (1) The coal cresol oil is selected as the raw material, which contains rich phenolic substances. The conventional method for extracting phenolic substances has problems such as serious pollution, high energy consumption and complex process. In this process, a simple alkali washing method is adopted. Compared with the conventional acid-base extraction, which requires additional acid to replace phenolic substances from the extraction phase, this process does not require acid washing and separation and purification, and can directly utilize the extraction phase, avoiding the problems of wastewater generation and separation energy consumption. KOH can not only be used for extraction, but also act as an activator in the carbonization process. The integration of extraction and activation also reduces the amount of alkali used, and the process is more green and environmentally friendly.

[0025] (2) KOH also acts as a catalyst for the synthesis of resin-like substances. After conventional resin synthesis, it needs to be washed to remove it to avoid affecting the performance of the resin. In this process, the alkali does not need to be removed, but is uniformly distributed in the resin-like substance during the reaction process, which plays a role in situ activation during carbonization and makes the pore size distribution uniform. At the same time, there is no need to use other additives, which simplifies the process and avoids the energy and environmental problems caused by subsequent treatment.

[0026] (3) The concentration of the amount of alkali affects the extraction, synthesis of resin-like substances, and pore-forming effect of the carbon adsorption material, among which the pore-forming effect is the most affected. If the amount of alkali is low, the pore-forming effect is not developed, resulting in a low specific surface area of the material and affecting the adsorption capacity of the material. If the amount of alkali is high, the pore structure of the material collapses, also resulting in a decrease in the specific surface area of the material. In addition, the amount of alkali also affects the extraction efficiency and the catalytic effect on the synthesis of resin. If the amount of alkali is too low, the extraction efficiency and the effect of resin synthesis are greatly reduced. Although a high amount of alkali can improve the extraction efficiency and the catalytic effect, it has an adverse effect on the pore-forming in the later stage. Based on this, the present application can obtain an adsorption material that takes into account the extraction efficiency, catalytic effect, and material adsorption performance by fine-tuning the amount of alkali.

[0027] (4) The coal naphtha oil-based carbon adsorption material prepared by the method of the present application has the advantages of developed voids, acid and alkali resistance, high stability, and the like, compared with other adsorbents such as MOFs and molecular sieves commonly used in the art. In addition, the coal naphtha oil-based carbon adsorption material not only realizes the separation and enrichment of methane, but also expands the high-value utilization path of coal tar and has good economic efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is the N2 adsorption-desorption curve of the POAC-0.5-600 adsorption material prepared in Example 1 at 77K. Figure 2 is the pore size distribution comparison of the POAC-0.5-600 adsorption material prepared in Example 1, the POAC-0.1-600 adsorption material in Example 3, and the POAC-1.0-600 adsorption material in Example 4.

[0029] Figure 3 is the methane and nitrogen adsorption curve of the adsorption material at 298 K and 100 kPa (taking the POAC-0.5-600 in Example 1, the POAC-0.1-600 in Example 3, and the POAC-1.0-600 in Example 4 as examples).

[0030] Figure 4 is the methane and nitrogen adsorption curve of the adsorption material at 273 K and 100 kPa (taking the POAC-0.5-600 in Example 1, the POAC-0.1-600 in Example 3, and the POAC-1.0-600 in Example 4 as examples).

[0031] Figure 5 is the adsorption selectivity of the adsorption material for CH4 / N2 mixed gas at 298 K calculated according to the IAST theory (taking the POAC-0.5-600 in Example 1, the POAC-0.1-600 in Example 3, and the POAC-1.0-600 in Example 4 as examples). DETAILED DESCRIPTION

[0032] The specific implementation of the technical solution of the present invention will be further illustrated below through specific embodiments.

[0033]

Example 1

[0034] Measure 6 ml of phenolic oil and 12 ml of 0.5 mol / L KOH solution, mix and shake, let stand, and collect the lower aqueous phase after separation. Weigh 0.02 mol of terephthalaldehyde and add it to 40 ml of methanol, then add 0.6 ml of ammonia water and stir for 20 min. After the terephthalaldehyde dissolves, add it to the extraction to obtain the lower aqueous phase solution and stir for 10 min to ensure homogeneity. Then, place the mixed solution in a forced-air drying oven and dry at 80 ℃ for 24 h to solidify and obtain the precursor of the carbon material. Activate the precursor by raising the temperature to the target temperature of 600 ℃ in a tube furnace under a nitrogen atmosphere at a rate of 5 ℃ / min for 2 h. After cooling to room temperature, disperse the obtained carbon material in 25 mL of 1 mol / L HCl solution, let stand for 12 h, and rinse with deionized water until the pH reaches neutral. After vacuum drying at 80 ℃ for 12 h, obtain the carbon adsorbent material, which is labeled POAC-0.5-600.

[0035] 100 mg of POAC-0.5-600 was weighed and degassed at 150 °C for 8 h to remove guest molecules and ensure the purity of the sample. Adsorption / desorption was performed using a Micromeritics 3Flex physical adsorption instrument at 77 K with N2, and the N2 adsorption / desorption curves were obtained. Figure 1 ).Depend on Figure 1 It can be seen that the prepared adsorbent material contains abundant microporous structures, and the presence of hysteresis loops indicates the existence of mesoporous structures. Further, the specific surface area of ​​the porous carbon was determined using BET (Brunauer-Emmett-Teller) theory or other relevant theoretical models. The pore size distribution of the sample was calculated using density functional theory (DFT), and the micropore volume was calculated using the t-plot method. The BET specific surface area was found to be 501.52 m². 2 / g, with a micropore area of ​​400.87 m² 2 / g, total pore volume is 0.2104 cm³ 3 / g.

[0036] 100 mg of POAC-0.5-600 was weighed and degassed at 150 °C for 8 h to remove guest molecules and ensure the purity of the sample. The adsorption of CH4 and N2 at 298 K was measured using a Micromeritics ASAP 2460 multichannel microporous adsorption analyzer, and adsorption isotherms were obtained. Then, the static adsorption selectivity of POAC-0.5-600 at 298 K for CH4 / N2 was calculated using the IAST model.

[0037]

Example 2

[0038] Measure 6 ml of phenolic oil and 18 ml of 0.3 mol / L KOH solution, mix and shake, let stand, and collect the lower aqueous phase after separation. Weigh 0.03 mol of terephthalaldehyde and add it to 40 ml of methanol, then add 1.0 ml of ammonia water and stir for 20 min. After the terephthalaldehyde dissolves, add it to the extraction layer to obtain the lower aqueous phase solution and stir for 10 min to ensure homogeneity. Then, place the mixed solution in a forced-air drying oven and dry at 80 ℃ for 24 h to solidify and obtain the precursor of the carbon material. Activate the precursor by raising the temperature to the target temperature of 600 ℃ in a tube furnace under a nitrogen atmosphere at a rate of 5 ℃ / min for 2 h. After cooling to room temperature, disperse the obtained carbon material in 25 mL of 1 mol / L HCl solution, let stand for 12 h, and rinse with deionized water until the pH reaches neutral. After vacuum drying at 80 ℃ for 12 h, obtain the carbon adsorbent material, which is labeled POAC-0.3-600.

[0039] The specific surface area of ​​the porous carbon was determined using the same testing and calculation methods as in Example 1, and the pore size distribution and micropore volume of the sample were calculated. The results showed that its BET specific surface area was 498.32 m². 2 / g, with a micropore area of ​​389.67 m². 2 / g, total pore volume is 0.195 cm³ 3 / g.

[0040]

Example 3

[0041] Take 5 ml of coal cresol oil and 50 ml of 0.1 mol / L KOH solution, mix and shake, stand, and take the lower layer after it is layered. Take 0.02 mol of p-xylylformaldehyde and add 50 ml of methanol, then add 1.5 ml of ammonia water and stir for 20 min. After the p-xylylformaldehyde is dissolved, extract to obtain the lower layer of the aqueous solution, stir for 10 min, and mix the two uniformly. Then put the mixed solution into a drying oven at 80 ℃ and dry for 24 h, and solidify to obtain the precursor of the carbon material. Use a tube furnace to activate at a rate of 5 ℃ / min to a target temperature of 600 ℃ under a nitrogen atmosphere for 2 h. After cooling to room temperature, disperse the obtained carbon material in 25 mL of 1 mol / L HCl solution, stand for 12 h, and wash with deionized water until the pH value reaches neutral. After vacuum drying at 80 ℃ for 12 h, the carbon adsorption material is obtained, which is marked as POAC-0.1-600.

[0042] The same test and calculation method as in Example 1 is used to determine the specific surface area of the porous carbon, and the pore size distribution and micropore volume of the sample are calculated. The results show that the BET specific surface area is 457.65 m 2 / g, the micropore area is 367.40 m 2 / g, and the total pore volume is 0.1915 cm 3 / g.

[0043]

Example 4

[0044] Take 5 ml of coal cresol oil and 10 ml of 1.0 mol / L KOH solution, mix and shake, stand, and take the lower layer after it is layered. Take 0.05 mol of p-xylylformaldehyde and add 50 ml of methanol, then add 2.5 ml of ammonia water and stir for 20 min. After the p-xylylformaldehyde is dissolved, extract to obtain the lower layer of the aqueous solution, stir for 10 min, and mix the two uniformly. Then put the mixed solution into a drying oven at 80 ℃ and dry for 24 h, and solidify to obtain the precursor of the carbon material. Use a tube furnace to activate at a rate of 5 ℃ / min to a target temperature of 600 ℃ under a nitrogen atmosphere for 2 h. After cooling to room temperature, disperse the obtained carbon material in 25 mL of 1 mol / L HCl solution, stand for 12 h, and wash with deionized water until the pH value reaches neutral. After vacuum drying at 80 ℃ for 12 h, the carbon adsorption material is obtained, which is marked as POAC-1.0-600.

[0045] The same test and calculation method as in Example 1 is used to determine the specific surface area of the porous carbon, and the pore size distribution and micropore volume of the sample are calculated. The results show that the BET specific surface area is 217.46 m 2 / g, the micropore area is 160.76 m 2 / g, and the total pore volume was 0.0958 cm 3 / g.

[0046] Example 5

[0047] 6 ml of cresol oil and 12 ml of 0.5 mol / L KOH solution were mixed, shaken, and allowed to stand until they were layered, and then the lower aqueous phase was taken for standby use. 0.02 mol of p-xylylene glycol was added to 40 ml of methanol, 0.6 ml of ammonia water was added, and stirring was performed for 20 min. After the p-xylylene glycol was dissolved, extraction was performed to obtain a lower aqueous phase solution, and stirring was performed for 10 min to mix the two uniformly. Then, the mixed solution was placed in a drying oven and dried at 80°C for 24 h, and a precursor of a carbon material was solidified. A tube furnace was used to activate the precursor in a nitrogen atmosphere at a rate of 5°C / min to a target temperature of 700°C for 2 h. After cooling to room temperature, the obtained carbon material was dispersed in 25 mL of 1 mol / L HCl solution, left to stand for 12 h, and washed with deionized water until the pH value reached neutral. After vacuum drying at 80°C for 12 h, a carbon adsorption material was obtained, which was labeled as POAC-0.5-700.

[0048] The same test and calculation method as in Example 1 was used to determine the specific surface area of the porous carbon, and the pore size distribution and micropore volume of the sample were calculated. The results showed that the BET specific surface area was 616.52 m 2 / g, the micropore area was 516.56 m 2 / g, and the total pore volume was 0.2735 cm 3 / g.

[0049] Example 6

[0050] 6 ml of cresol oil and 12 ml of 0.5 mol / L KOH solution were mixed, shaken, and allowed to stand until they were layered, and then the lower aqueous phase was taken for standby use. 0.02 mol of p-xylylene glycol was added to 40 ml of methanol, 0.6 ml of ammonia water was added, and stirring was performed for 20 min. After the p-xylylene glycol was dissolved, extraction was performed to obtain a lower aqueous phase solution, and stirring was performed for 10 min to mix the two uniformly. Then, the mixed solution was placed in a drying oven and dried at 80°C for 24 h, and a precursor of a carbon material was solidified. A tube furnace was used to activate the precursor in a nitrogen atmosphere at a rate of 5°C / min to a target temperature of 800°C for 2 h. After cooling to room temperature, the obtained carbon material was dispersed in 25 mL of 1 mol / L HCl solution, left to stand for 12 h, and washed with deionized water until the pH value reached neutral. After vacuum drying at 80°C for 12 h, a carbon adsorption material was obtained, which was labeled as POAC-0.5-800.

[0051] The specific surface area of the porous carbon was determined by using the same testing and calculation method as in Example 1, and the pore size distribution and micropore volume of the sample were calculated. The results show that the BET specific surface area is 1115.09 m 2 / g, the micropore area is 894.63 m 2 / g, and the total pore volume is 0.4754 cm 3 / g.

[0052] Figure 2 is a comparison of the pore size distribution of the POAC-0.5-600 prepared in Example 1, the POAC-0.1-600 in Example 3, and the POAC-1.0-600 in Example 4. By comparing and analyzing the parameter conditions for preparing the adsorption materials in Examples 1, 3, and 4, and combining with Figure 2 , it can be clearly seen that the concentration of the lye affects the distribution of the pore structure. Figure 2 It is shown that when the alkali concentration is too high, the micropore pore size distribution is not concentrated and two peak values appear, indicating that when the alkali amount is too high, the pore-forming ability is enhanced but is not conducive to improving the CH4 / N2 selectivity; when the alkali amount is low, the pore-forming ability is not strong, the specific surface area of the material is low, and the separation effect is poor. Only when the alkali amount is appropriate, a material with a high specific surface area, a concentrated pore size distribution, and being conducive to adsorbing and separating CH4 / N2 can be obtained.

[0053] Figure 3 , Figure 4 are the adsorption conditions of methane and nitrogen of the POAC-0.5-600 prepared in Example 1, the POAC-0.1-600 in Example 3, and the POAC-1.0-600 in Example 4 at 298 K, 273 K, and 100 kPa. Figure 3 , Figure 4 The experimental data of Table 2 show that with the increase of the concentration of the lye, the adsorption performance of the adsorption material prepared by the method of the present application first increases and then decreases, and therefore, only by selecting a suitable concentration of the lye in the preparation process, the prepared adsorption material can exhibit excellent adsorption capacity.

[0054] The selectivity is an important index for measuring the adsorption and separation capacity of a material. Figure 5 is the adsorption selectivity of the POAC-0.5-600 prepared in Example 1, the POAC-0.1-600 in Example 3, and the POAC-1.0-600 in Example 4 for CH4 / N2 mixed gas at 298 K, which is calculated according to the IAST theory. Figure 5 The results of Table 3 show that the CH4 / N2 selectivity also decreases with the increase of the concentration of the lye, and the highest IAST selectivity of the adsorption material prepared by the method of the present application can reach 7.97, indicating that it has broad application prospects in the field of low-concentration gas separation and concentration.

[0055] In order to further find the best preparation condition, the present application carries out the following comparative test.

[0056] Comparative Example 1

[0057] The same as Example 1, except that the concentration of KOH solution selected is 0.05 mol / L, and a carbon adsorption material is prepared, which is marked as POAC-0.05-600. The BET specific surface area of Comparative Example 1 is measured to be 147.34 m 2 / g, micropore area is 112.45 m 2 / g, and total pore volume is 0.0825 cm 3 / g by using the same test method as step S2 of Example 1.

[0058] Comparative Example 2

[0059] The same as Example 1, except that the concentration of KOH solution selected is 1.5 mol / L, and a carbon adsorption material is prepared, which is marked as POAC-1.5-600. The BET specific surface area of Comparative Example 2 is measured to be 234.67 m 2 / g, micropore area is 177.84 m 2 / g, and total pore volume is 0.08958 cm 3 / g by using the same test method as step S2 of Example 1.

[0060] Comparative Example 3

[0061] The same as Example 1, except that the KOH solution is replaced by NaOH solution with the same concentration, and a carbon adsorption material is prepared, which is marked as POAC-Na-0.5-600.

[0062] Comparative Example 4

[0063] The same as Example 1, except that the terephthalaldehyde is replaced by furfural, and a carbon adsorption material is prepared, which is marked as POAC-FU-0.5-600.

[0064] Comparative Example 5

[0065] The same as Example 1, except that the terephthalaldehyde is replaced by formaldehyde, and a carbon adsorption material is prepared, which is marked as POAC-FA-0.5-600.

[0066] The adsorption materials of Examples 1-6 and Comparative Examples 1-5 are subjected to static adsorption test of methane and nitrogen according to the method of step S3 of Example 1, and the IAST model is used to calculate the static adsorption selectivity of CH4 / N2 at 298K and normal pressure. The experimental results are shown in Table 1 below.

[0067] Table 1

[0068]

[0069] The activated carbon adsorption materials prepared by example 1, example 5 and example 6 at different carbonization temperatures of 600 DEG C, 700 DEG C and 800 DEG C respectively and the same amount of alkali can be obtained that with the increase of temperature, the specific surface area of the material increases, the adsorption capacity increases but the selectivity of CH4 / N2 decreases, which shows that the increase of carbonization temperature causes more defects of the carbon material, more adsorption space is produced but it is not conducive to separate CH4 / N2.

[0070] Comparative example 1 and comparative example 2 further embody the influence of the amount of alkali on the material adsorption, KOH is used as a catalyst for resin polymerization, when the added KOH is too little, the resin cannot be synthesized or the synthesized product is too little. In comparative example 3, KOH is replaced by NaOH, the adsorption and separation capacity of the obtained material also decreases, which proves that KOH shows excellent performance in the process. In comparative example 4 and comparative example 5, terephthaldehyde is replaced by other aldehyde substances (formaldehyde, furfural), terephthaldehyde as a raw material has the best performance of the carbon adsorption material, and terephthaldehyde is solid, compared with formaldehyde and furfural, it is not easy to volatilize and has lower toxicity than formaldehyde and furfural.

[0071] Through the comparison and analysis of the adsorption test data of the examples and the above comparative examples, it can be seen that the activator KOH has an extremely important role in the preparation process of the adsorption material of the present application, which integrates extraction, catalysis and pore-forming functions in one, greatly reduces the amount of KOH, from coal tar oil to carbon adsorption material, the present application alleviates the problems of environmental pollution and resource consumption in the traditional process, at the same time, the application of the obtained carbon material in the adsorption of low-concentration methane not only realizes the high-value utilization of coal tar oil, but also creates economic benefits.

[0072] The above description of the examples is for the purpose of enabling and using the present application by those of ordinary skill in the art. Those skilled in the art can easily make various modifications to the examples, and apply the general principles described herein to other examples without creative labor. Therefore, the present application is not limited to the above examples, and the improvements and modifications made by those skilled in the art without departing from the scope of the present application should be within the scope of protection of the present application.

Claims

1. A method for preparing a coal cresol oil-based carbon adsorption material, comprising the following steps: 1) mixing a certain amount of an alkali solution and coal cresol oil according to a certain volume ratio, stirring, standing for layering, separating, and taking the lower liquid phase for standby; 2) adding an aldehyde compound into a methanol solvent, then adding a certain amount of ammonia water to dissolve it, to obtain a clear solution; 3) mixing the lower liquid phase obtained in step 1) and the clear solution obtained in step 2), stirring to mix them uniformly, and then solidifying at 80 ℃ for 24 h to obtain a resin-like intermediate; 4) transferring the resin-like intermediate obtained in step 3) into a tube furnace, and performing high-temperature carbonization treatment under an inert atmosphere, and cooling to room temperature after the carbonization is completed, to obtain a solid material; 5) acid washing, filtering, and drying the solid material obtained in step 4) to obtain the coal cresol oil-based carbon adsorption material; In step 1), the alkali solution is a KOH solution, and the concentration ranges from 0.1 mol / L to 1.0 mol / L; the alkali solution and the coal cresol oil are mixed according to a volume ratio of 2-10.

2. The production method according to claim 1, wherein In step 2), the aldehyde compound is p-xylylene.

3. The production method according to claim 1, characterized by, In step 2), the aldehyde compound is added into the methanol solvent to configure an aldehyde methanol solution with a concentration ranging from 0.1 mol / L to 1 mol / L.

4. The production method according to claim 1, wherein In step 2), the volume ratio of ammonia water to methanol ranges from 0.01 to 0.

05.

5. The production method according to claim 1, wherein In step 3), the volume ratio of the lower liquid phase to the clear solution ranges from 0.1 to 1.

0.

6. The production method according to claim 1, characterized by, In step 4), the inert atmosphere is nitrogen, argon, or helium, and the high-temperature carbonization treatment temperature ranges from 600 ℃ to 800 ℃.

7. The coal phenol oil-based carbon adsorbent material produced by the production method according to any one of claims 1 to 6, characterized by, The method is suitable for the field of coalbed methane separation and purification.

8. The coal phenol-based carbon adsorbent material of claim 7, wherein, The coal cresol oil-based carbon adsorption material is applied to the separation of CH4 / N2 mixed gas in coalbed methane by using an adsorption method, and the adsorption conditions are 0 ℃-30 ℃ and a pressure of 0.1 MPa-1 MPa.

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