Regeneration method of waste carbon molecular sieve

Abstract

The invention relates to a regeneration method of a waste carbon molecular sieve, and belongs to the technical field of adsorbents. The technical problem to be solved by the invention is to provide the regeneration method of the waste carbon molecular sieve. The regeneration method comprises the following steps: a, polymerization: dissolving a phenolic substance and an aldehyde substance in a solvent to form an impregnation liquid, mixing and impregnating the impregnation liquid and an invalid carbon molecular sieve, taking out, heating, and carrying out a polymerization reaction to obtain a polymerization product; and b, carbonization: roasting the polymerization product in a protective atmosphere to obtain the regenerated carbon molecular sieve. According to the regeneration method of the waste carbon molecular sieve, the failed carbon molecular sieve is regenerated through in-situ polymerization modification of the phenolic resin, the method is simple, and the regenerated carbon molecular sieve is high in performance and quality and even exceeds the performance and quality of new carbon molecular sieves of the same kind.

Description

Technical Field

[0001] The present invention relates to a regeneration method for waste carbon molecular sieves and belongs to the technical field of adsorbents. Background Art

[0002] Carbon molecular sieves (CMS) are a new type of adsorbent developed in the 1970s of the 20th century and are an excellent non-polar carbonaceous material. Currently, carbon molecular sieves are widely used in pressure swing adsorption nitrogen production equipment for separating N2 and O2.

[0003] In the air nitrogen production process, using carbon molecular sieves as adsorbents, since carbon molecular sieves have a strong affinity for molecules such as water and oil, it is required that the raw air must be very clean. However, due to reasons such as the use of air compressors in pressure swing adsorption, water, oil vapor and other harmful chemical gases are inevitably introduced into the air, resulting in the blockage of the micropores of the nitrogen-producing carbon molecular sieves and the gradual decline of the separation effect. This is the so-called "failure" of the carbon molecular sieves, which is also called "poisoning".

[0004] In order to save costs, it is necessary to recycle and regenerate the failed waste carbon molecular sieves.

[0005] The Chinese invention patent with the application number 200910308853.0 discloses an activation and regeneration process for nitrogen-producing carbon molecular sieves, including the following production steps: a. Clean treatment of poisoned carbon molecular sieves, b. High-temperature nitrogen drying, c. Nitrogen-based high-temperature carbonization. The Chinese invention patent with the application number 201210301937.3 discloses a regeneration method for nitrogen-producing carbon molecular sieves, including steps such as pickling, water washing, carbonization, activation, and pore adjustment. The Chinese invention patent with the application number 201610430414.7 discloses a regeneration method for poisoned carbon molecular sieves, which includes the following steps: S100: Pickling: Immerse the poisoned carbon molecular sieves in a hydrochloric acid solution for sufficient soaking; S200: Water washing: Rinse the pickled poisoned carbon molecular sieves with clean water 2 - 3 times; S300: Solvent cleaning: Immerse the water-washed poisoned carbon molecular sieves in an organic solvent for sufficient soaking; S400: Pore adjustment: Place the poisoned carbon molecular sieves in a nitrogen environment and perform pore adjustment at 600 - 750 °C.

[0006] It can be seen that the current regeneration methods for carbon molecular sieves have relatively complex steps. In addition to procedures such as pickling and water washing, the production process of carbon molecular sieves is also repeated. The whole process is complex, costly, has poor effects, and causes secondary pollution. The carbon molecular sieves obtained thus have an adsorption effect that is at most equivalent to that before regeneration. Summary of the Invention

[0007] Aiming at the above defects, the technical problem solved by the present invention is to provide a regeneration method for waste carbon molecular sieves.

[0008] The regeneration method of waste carbon molecular sieve of the present invention comprises the following steps:

[0009] a. Polymerization: Dissolve phenolic substances and aldehyde substances in a solvent to form an impregnating solution, then mix the impregnating solution with the deactivated carbon molecular sieve for impregnation, take it out, raise the temperature for polymerization reaction to obtain a polymerization product;

[0010] b. Carbonization: Roast the polymerization product under a protective atmosphere to obtain the regenerated carbon molecular sieve.

[0011] In an embodiment of the present invention, in step a, the phenolic substances are phenol, catechol, resorcinol, hydroquinone, m-aminophenol, p-aminophenol, the aldehyde substance is formaldehyde, and the solvent is water.

[0012] Specifically, the molar ratio of the phenolic substance to the aldehyde substance is 0.2 - 1:1.

[0013] In an embodiment of the present invention, in the impregnating solution, the concentration of the phenolic substance is 0.05 - 0.7 g / mL.

[0014] In an embodiment of the present invention, in step a, the impregnating solution further comprises a catalyst. In a specific embodiment, the catalyst is preferably sodium hydroxide.

[0015] In an embodiment of the present invention, in step a, the impregnation time is 0.5 - 12 h; preferably, the impregnation time is 1 h.

[0016] In an embodiment of the present invention, in step a, the temperature of the polymerization reaction is 80 - 120 °C, and the reaction time is 20 - 40 h; preferably, the temperature of the polymerization reaction is 100 °C, and the reaction time is 24 h.

[0017] In an embodiment of the present invention, in step b, the roasting temperature is 600 - 800 °C, and the roasting time is 1 - 5 h; preferably, the roasting temperature is 700 °C, and the roasting time is 2 h.

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

[0019] The regeneration method of waste carbon molecular sieve of the present invention uses in-situ polymerization modification of phenolic resin to regenerate the deactivated carbon molecular sieve. The method is simple, and the performance and quality of the regenerated carbon molecular sieve are both relatively high, even exceeding those of the same kind of new carbon molecular sieve. Specific Embodiments

[0020] The regeneration method of waste carbon molecular sieve of the present invention comprises the following steps:

[0021] a. Polymerization: Dissolve phenolic substances and aldehyde substances in a solvent to form an impregnating solution. Then, mix the impregnating solution with the spent carbon molecular sieve for impregnation, take it out, and raise the temperature for polymerization reaction to obtain a polymerization product.

[0022] b. Carbonization: Calcinate the polymerization product under a protective atmosphere to obtain a regenerated carbon molecular sieve.

[0023] In one embodiment of the present invention, in step a, the phenolic substances are phenol, catechol, resorcinol, hydroquinone, m-aminophenol, p-aminophenol, the aldehyde substance is formaldehyde, and the solvent is water.

[0024] Specifically, the molar ratio of the phenolic substance to the aldehyde substance is 0.2 - 1:1.

[0025] In one embodiment of the present invention, in the impregnating solution, the concentration of the phenolic substance is 0.05 - 0.7 g / mL.

[0026] In one embodiment of the present invention, in step a, the impregnating solution further includes a catalyst. Commonly used phenolic resin polymerization catalysts in the art are applicable to the present invention. In a specific embodiment, the catalyst is preferably sodium hydroxide. The concentration of the catalyst is a conventional concentration in the art and will not be elaborated here.

[0027] To save raw materials, the impregnation in the present invention is preferably equal-volume impregnation.

[0028] In one embodiment of the present invention, in step a, the impregnation time is 0.5 - 12 h; preferably, the impregnation time is 1 h.

[0029] In one embodiment of the present invention, in step a, the temperature of the polymerization reaction is 80 - 120 °C, and the reaction time is 20 - 40 h; preferably, the temperature of the polymerization reaction is 100 °C, and the reaction time is 24 h.

[0030] In one embodiment of the present invention, in step b, the calcination temperature is 600 - 800 °C, and the calcination time is 1 - 5 h; preferably, the calcination temperature is 700 °C, and the calcination time is 2 h.

[0031] The following further describes the specific embodiments of the present invention in conjunction with examples, and the present invention is not limited to the scope of the described examples. The spent carbon molecular sieve in the examples is the spent CMS-Z220 carbon molecular sieve.

[0032] Examples 1 - 3

[0033] 1. Pretreatment of the spent adsorbent: Place the spent carbon molecular sieve substrate in an oven at 130 °C and dry it overnight to remove the gas residue in the carbon molecular sieve.

[0034] 2. Preparation of Impregnating Solution: Weigh a certain amount of phenol, sodium hydroxide, and 38% formaldehyde solution into a 100 mL beaker respectively, then dilute it to 90 mL with deionized water. Next, stir it with a magnetic stirrer at room temperature for 2 h to obtain a uniformly mixed impregnating solution. The dosages of phenol, sodium hydroxide, and 38% formaldehyde solution in each example and comparative example are shown in Table 1.

[0035] 3. Polymerization: Take multiple clean beakers, weigh 10.00 g of adsorbent into each beaker respectively, and use a pipette to slowly drop 9 mL of impregnating solution into the beaker containing the spent adsorbent. After the dropping is completed, let it stand at room temperature for 1 h to ensure complete impregnation. Then put the impregnated molecular sieve into an oven at 100 °C and react for 24 h.

[0036] 4. Carbonization: Transfer the reacted adsorbent to a tubular furnace, calcine it at 700 °C under the protection of He for 2 h, and after completion, transfer it to a glass desiccator for storage, which is the regenerated carbon molecular sieve.

[0037] Table 1

[0038] Example No. Failed CMS-Z220 / g Phenol / g NaOH / g 38% Formaldehyde / g Example 1 10 15 0.8 35 Example 2 10 20 1.1 47 Example 3 10 25 1.3 59 Comparative Example 1 10 0 0 0

[0039] The performances of the regenerated carbon molecular sieves, spent CMS-Z220, and CMS-Z220 in the above examples and comparative examples are shown in Table 2:

[0040] Table 2

[0041] Example No. <![CDATA[Bulk specific gravity, kg / m 3 > Nitrogen Concentration, % <![CDATA[Production nitrogen volume, m 3 / h.t]]> Air-Nitrogen Ratio, % Example 1 630 99.5 200 3.2 Example 2 630 99.5 215 3.1 Example 3 630 99.5 205 3.2 Comparative Example 1 630 99.5 140 3.8 Failed CMS-Z220 630 99.5 160 3.6 CMS-Z220 630 99.5 220 3.1

[0042] Note: The above performances are all measured at an adsorption pressure of 0.8 MPa, and the adsorption cycle is 1×50 s.

[0043] It can be seen that the present invention adopts in-situ polymerization modification of phenolic resin, which can regenerate the spent carbon molecular sieve. The method is simple, and the performance and quality of the regenerated carbon molecular sieve are both relatively high, even exceeding those of the same type of new carbon molecular sieve.

Claims

1. A method for regenerating waste carbon molecular sieves, characterized in that, It includes the following steps: a. Polymerization: Dissolve phenolic substances and aldehyde substances in a solvent to form an impregnating solution. Then, mix the impregnating solution with the deactivated carbon molecular sieve for impregnation, take it out, raise the temperature to carry out a polymerization reaction to obtain a polymerization product; b. Carbonization: Calcinate the polymerization product under a protective atmosphere to obtain a regenerated carbon molecular sieve.

2. The regeneration method of waste carbon molecular sieve according to claim 1, characterized in that: In step a, the phenolic substances are phenol, catechol, resorcinol, hydroquinone, m-aminophenol, p-aminophenol, the aldehyde substance is formaldehyde, and the solvent is water.

3. The regeneration method of the waste carbon molecular sieve according to claim 1, characterized in that: The molar ratio of the phenolic substance to the aldehyde substance is 0.2 - 1:

1.

4. The regeneration method of the waste carbon molecular sieve according to claim 1, wherein: In the impregnating solution, the concentration of the phenolic substance is 0.05 - 0.7 g / mL.

5. The regeneration method of waste carbon molecular sieve according to claim 1, characterized in that: In step a, the impregnating solution further contains a catalyst; preferably, the catalyst is sodium hydroxide.

6. The regeneration method of waste carbon molecular sieve according to claim 1, characterized in that: In step a, the impregnation time is 0.5 - 12 h; preferably, the impregnation time is 1 h.

7. The regeneration method of waste carbon molecular sieve according to claim 1, characterized in that: In step a, the temperature of the polymerization reaction is 80 - 120 °C, and the reaction time is 20 - 40 h; preferably, the temperature of the polymerization reaction is 100 °C, and the reaction time is 24 h.

8. The regeneration method of waste carbon molecular sieve according to claim 1, wherein: In step b, the calcination temperature is 600 - 800 °C, and the calcination time is 1 - 5 h; preferably, the calcination temperature is 700 °C, and the calcination time is 2 h.