Process for the preparation of a carbon dioxide adsorbent

Abstract

The application belongs to the technical field of gas adsorption, and particularly relates to a preparation method of a carbon dioxide adsorbent. The method comprises the following steps: rolling into balls after mixing zeolite, diatomite, polystyrene microsphere powder and a binder; drying the prepared balls to obtain honeycomb-shaped balls with a diameter of 1-1.5 mm; spraying an organic amine solution into the prepared honeycomb-shaped balls until adsorption saturation, and then coating the balls with a mixture of calcium hydroxide and calcium oxide in the presence of the binder to obtain thorned balls with a diameter of 2-3 mm; and drying the prepared thorned balls at 140-160 DEG C for 40-60 min to obtain the carbon dioxide adsorbent. The honeycomb-shaped balls are formed by first drying, the internal pores are used for adsorbing the organic amine, then the adsorption-saturated balls are coated with the mixture of calcium hydroxide and calcium oxide to form micro spikes with a uniform surface, and then dried again, so that the surface adsorption area of the carbon dioxide is increased.

Description

Technical Field

[0001] This invention belongs to the field of gas adsorption technology, specifically relating to a method for preparing a carbon dioxide adsorbent. Background Technology

[0002] Carbon dioxide adsorbents are materials that effectively adsorb carbon dioxide gas and have wide applications in many fields. In environmental protection, carbon dioxide adsorbents can be used to reduce the concentration of carbon dioxide in the atmosphere, thereby combating global warming and climate change. For example, they can be used in industrial emission control, such as tail gas treatment in fossil fuel power plants, to reduce carbon dioxide emissions. In carbon capture and storage (CCS) technology in the field of energy conversion and storage, carbon dioxide adsorbents are used to capture carbon dioxide from the combustion process and then store it to prevent its release into the atmosphere. Furthermore, they can be used in carbon dioxide enhanced oil and gas recovery (EOR) processes to improve the efficiency of oil extraction. Simultaneously, carbon dioxide adsorbents can also be used to improve indoor air quality, especially in enclosed or poorly ventilated spaces such as offices, schools, residences, and aircraft cabins. By adsorbing carbon dioxide, they help maintain fresh indoor air and suitable carbon dioxide levels.

[0003] In the medical field, carbon dioxide adsorbents are commonly used in hospitals and medical facilities. They can be applied in operating rooms and ventilators to maintain air quality in operating rooms and patient care areas, ensuring the safety of patients and medical staff. Carbon dioxide adsorbents also have applications in aerospace and deep-sea diving. In astronauts' spacesuits and deep-sea divers' breathing systems, they remove carbon dioxide generated during respiration, ensuring that the carbon dioxide concentration in the breath gas remains at a safe level. Furthermore, carbon dioxide has extensive applications in agriculture and horticulture. For example, carbon dioxide adsorbents can be used to control greenhouse gas concentrations to optimize plant growth conditions. In greenhouses, they can help regulate carbon dioxide concentrations, promote plant photosynthesis, and increase crop yields. In the food and beverage industry, carbon dioxide adsorbents can be used to control the atmosphere within packaging, extending product shelf life while maintaining product taste and freshness.

[0004] The materials and technologies for carbon dioxide adsorbents are constantly being developed and improved to enhance adsorption efficiency, reduce costs, and expand applications. These materials can be solid adsorbents, such as activated carbon and zeolite, or liquid chemical adsorbents, such as amine solutions. With the increasing demand for reducing carbon dioxide emissions and addressing climate change, however, current commercially available carbon dioxide adsorbent products tend to generate significant amounts of dust during transportation and use, and their reliance on a single adsorption method results in poor carbon dioxide absorption performance.

[0005] Patent CN104399359A discloses a medical carbon dioxide absorbent and its preparation method. The absorbent comprises the following raw materials: calcium hydroxide, sodium hydroxide, potassium hydroxide, lithium hydroxide, humectant, deionized water, methyl violet, and disintegrant. The preparation steps are as follows: Step 1, weigh the raw materials according to the specified weight proportions, and pulverize the calcium hydroxide and sieve it to obtain calcium hydroxide powder for later use; Step 2, mix the calcium hydroxide powder, sodium hydroxide, potassium hydroxide, lithium hydroxide, humectant, and deionized water, stir for 5-12 minutes, add the disintegrant and methyl violet, continue stirring and heating for 5-8 minutes until it forms a clump, then extrude it into cylindrical strips with a diameter of 1-2 mm using an extruder; Step 3, dry the cylindrical strips at 120-140℃ for 4-6 hours, and then grind them to 800 mesh to obtain the finished product. This patent has a simple structure, and the finished product is a powder with extremely small particle size. However, when used for medical carbon dioxide adsorption, it generates a large amount of dust during transportation and use, and its absorption method is singular with a poor absorption rate. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing a carbon dioxide adsorbent, which has good carbon dioxide absorption effect and produces no dust during transportation and use.

[0007] The method for preparing the carbon dioxide adsorbent of the present invention includes the following steps:

[0008] (1) Take zeolite, diatomaceous earth, polystyrene microsphere powder and binder, mix them and roll them into balls with a diameter of 1-1.5 mm;

[0009] (2) Dry the balls obtained in step (1) at 100-300℃ for 1-1.5h to obtain honeycomb-shaped balls with a diameter of 1-1.5mm;

[0010] (3) Spray an organic amine solution into the honeycomb spheres obtained in step (2) until the adsorption is saturated, and then use a mixture of calcium hydroxide and calcium oxide to coat the spheres into spiky spheres with a diameter of 2-3 mm in the presence of an adhesive.

[0011] (4) Dry the spiky balls obtained in step (3) at 140-160℃ for 40-60 minutes to obtain the carbon dioxide adsorbent.

[0012] The polystyrene microsphere powder mentioned in step (1) has a particle size of 100-200 mesh.

[0013] The mass ratio of zeolite, diatomaceous earth and polystyrene microsphere powder in step (1) is (50-70):(10-30):(10-30).

[0014] The amount of adhesive used in step (1) is 25%-35% of the total mass of zeolite, diatomaceous earth, and polystyrene microsphere powder.

[0015] The organic amine mentioned in step (3) is one or more of diethanolamine, triethanolamine, and N-methyldiethanolamine.

[0016] The organic amine solution in step (3) has a mass concentration of 15%-25%.

[0017] The mass ratio of calcium hydroxide and calcium oxide in step (3) is (92-95):(5-8).

[0018] The amount of adhesive used in step (3) is 25%-35% of the total mass of calcium hydroxide and calcium oxide.

[0019] The adhesive is a mixture of water and polyvinyl alcohol in a mass ratio of 50000:(260-350).

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] 1) The present invention involves drying in two steps. The first drying step is to volatilize the polystyrene microsphere powder with a particle size of 100-200 mesh that is uniformly distributed in the sphere, so that the interior of the sphere forms uniform and fine micropores, thereby preparing a honeycomb sphere. The micropores inside the sphere are used to adsorb organic amines as much as possible. Then, the saturated sphere is coated with a mixture of calcium hydroxide and calcium oxide. In the presence of an adhesive, uniformly distributed micro-spiks are formed on the surface of the sphere, and then it is dried.

[0022] 2) This invention utilizes a mixture of calcium hydroxide and calcium oxide to coat the surface of the sphere, forming uniformly distributed micro-spiky spikes on the sphere surface, which increases the surface adsorption area of ​​carbon dioxide and generates more adsorption gaps in the accumulated carbon dioxide absorbent, which has significant advantages over conventional granular and columnar carbon dioxide absorbents.

[0023] 3) This invention precisely controls the time and temperature of the second drying process to ensure that the outer surface of the barbed balls is dry, while also preventing the organic amines inside the barbed balls from turning into powder, which would weaken the carbon dioxide adsorption capacity of the product and affect the adsorption of carbon dioxide by the organic amines.

[0024] 4) This invention precisely controls the amount of calcium oxide used, resulting in the highest spike formation rate, maximizing the surface adsorption area of ​​the carbon dioxide adsorbent, creating more adsorption gaps in the accumulated carbon dioxide adsorbent, which is more conducive to carbon dioxide adsorption, while ensuring the strength of the spikes and preventing them from breaking and falling off due to bumps during transportation and use. Detailed Implementation

[0025] The present invention will be further described below with reference to the embodiments, but the scope of protection of the present invention is not limited thereto.

[0026] Unless otherwise specified, all raw materials used in the examples were commercially available.

[0027] Example 1

[0028] The method for preparing the carbon dioxide adsorbent includes the following steps:

[0029] (1) Take 180 kg of zeolite, 60 kg of diatomaceous earth, 60 kg of 200 mesh polystyrene microsphere powder and 90 kg of binder, mix them and roll them into balls with a diameter of 1.5 mm.

[0030] (2) The balls obtained in step (1) are dried at 200°C for 1.5 hours to obtain honeycomb-shaped balls with a diameter of 1.5 mm;

[0031] (3) Spray a 30% triethanolamine solution into the honeycomb spheres obtained in step (2) until the adsorption is saturated, and then use a mixture of calcium hydroxide, calcium oxide and adhesive in a mass ratio of 94:6:30 to coat the spheres into spiked spheres with a diameter of 3 mm.

[0032] (4) Dry the spiky balls obtained in step (3) at 150°C for 50 minutes to obtain the carbon dioxide adsorbent.

[0033] The adhesive is a mixture of water and polyvinyl alcohol in a mass ratio of 50000:260.

[0034] Example 2

[0035] The method for preparing the carbon dioxide adsorbent includes the following steps:

[0036] (1) Take 180 kg of zeolite, 60 kg of diatomaceous earth, 60 kg of 100-mesh polystyrene microsphere powder and 90 kg of binder, mix them and roll them into balls with a diameter of 1.5 mm.

[0037] (2) The balls obtained in step (1) are dried at 200°C for 1.5 hours to obtain honeycomb-shaped balls with a diameter of 1.5 mm;

[0038] (3) Spray a 30% triethanolamine solution into the honeycomb spheres obtained in step (2) until the adsorption is saturated, and then use a mixture of calcium hydroxide, calcium oxide and adhesive in a mass ratio of 92:8:30 to coat the spheres into spiked spheres with a diameter of 3 mm.

[0039] (4) Dry the spiky balls obtained in step (3) at 160°C for 40 minutes to obtain the carbon dioxide adsorbent.

[0040] The adhesive is a mixture of water and polyvinyl alcohol in a mass ratio of 50000:260.

[0041] Example 3

[0042] The method for preparing the carbon dioxide adsorbent includes the following steps:

[0043] (1) Take 180 kg of zeolite, 60 kg of diatomaceous earth, 60 kg of 200 mesh polystyrene microsphere powder and 90 kg of binder, mix them and roll them into balls with a diameter of 1.5 mm.

[0044] (2) The balls obtained in step (1) are dried at 200°C for 1.5 hours to obtain honeycomb-shaped balls with a diameter of 1.5 mm;

[0045] (3) Spray a 30% triethanolamine solution into the honeycomb spheres obtained in step (2) until the adsorption is saturated, and then use a mixture of calcium hydroxide, calcium oxide and adhesive in a mass ratio of 95:5:30 to coat the spheres into spiked spheres with a diameter of 3 mm.

[0046] (4) Dry the spiky balls obtained in step (3) at 150°C for 50 minutes to obtain the carbon dioxide adsorbent.

[0047] The adhesive is a mixture of water and polyvinyl alcohol in a mass ratio of 50000:260.

[0048] Example 4

[0049] The method for preparing the carbon dioxide adsorbent includes the following steps:

[0050] (1) Take 180 kg of zeolite, 60 kg of diatomaceous earth, 60 kg of 200 mesh polystyrene microsphere powder and 90 kg of binder, mix them and roll them into balls with a diameter of 1.5 mm.

[0051] (2) The balls obtained in step (1) are dried at 200°C for 1.5 hours to obtain honeycomb-shaped balls with a diameter of 1.5 mm;

[0052] (3) Spray a 30% N-methyldiethanolamine solution into the honeycomb spheres obtained in step (2) until the adsorption is saturated, and then use a mixture of calcium hydroxide, calcium oxide and binder in a mass ratio of 94:6:30 to coat the spheres into spiked spheres with a diameter of 3 mm.

[0053] (4) Dry the spiky balls obtained in step (3) at 150°C for 50 minutes to obtain the carbon dioxide adsorbent.

[0054] The adhesive is a mixture of water and polyvinyl alcohol in a mass ratio of 50000:260.

[0055] Comparative Example 1

[0056] The method for preparing the carbon dioxide adsorbent includes the following steps:

[0057] (1) Take 180 kg of zeolite, 60 kg of diatomaceous earth and 72 kg of binder, mix them and roll them into a ball with a diameter of 1.5 mm;

[0058] (2) The balls obtained in step (1) are dried at 200℃ for 1.5h to obtain balls with a diameter of 1.5mm;

[0059] (3) Spray a 30% triethanolamine solution onto the ball obtained in step (2) until adsorption saturation, and then coat it with a mixture of calcium hydroxide, calcium oxide and binder in a mass ratio of 94:6:30 to form a spiky ball with a diameter of 3 mm.

[0060] (4) Dry the spiky balls obtained in step (3) at 150°C for 50 minutes to obtain the carbon dioxide adsorbent.

[0061] The adhesive is a mixture of water and polyvinyl alcohol in a mass ratio of 50000:260.

[0062] Comparative Example 2

[0063] The method for preparing the carbon dioxide adsorbent includes the following steps:

[0064] (1) Take 180 kg of zeolite, 60 kg of diatomaceous earth, 60 kg of 200 mesh polystyrene microsphere powder and 90 kg of binder, mix them and roll them into balls with a diameter of 1.5 mm.

[0065] (2) The balls obtained in step (1) are dried at 200°C for 1.5 hours to obtain honeycomb-shaped balls with a diameter of 1.5 mm;

[0066] (3) Spray a 30% N-methyldiethanolamine solution into the honeycomb spheres obtained in step (2) until the adsorption is saturated, and then use a mixture of calcium hydroxide and adhesive in a mass ratio of 100:30 to coat the spheres into spiked spheres with a diameter of 3 mm.

[0067] (4) Dry the spheres obtained in step (3) at 150°C for 50 minutes to obtain the carbon dioxide adsorbent.

[0068] The adhesive is a mixture of water and polyvinyl alcohol in a mass ratio of 50000:260.

[0069] Comparative Example 3

[0070] The method for preparing the carbon dioxide adsorbent includes the following steps:

[0071] (1) Take 180 kg of zeolite, 60 kg of diatomaceous earth, 60 kg of 200 mesh polystyrene microsphere powder and 90 kg of binder, mix them and roll them into balls with a diameter of 1.5 mm.

[0072] (2) The balls obtained in step (1) are dried at 200°C for 1.5 hours to obtain honeycomb-shaped balls with a diameter of 1.5 mm;

[0073] (3) Spray a 30% triethanolamine solution into the honeycomb spheres obtained in step (2) until the adsorption is saturated, and then use a mixture of calcium hydroxide, calcium oxide and adhesive in a mass ratio of 90:10:30 to coat the spheres into spiked spheres with a diameter of 3 mm.

[0074] (4) Dry the spiky balls obtained in step (3) at 150°C for 50 minutes to obtain the carbon dioxide adsorbent.

[0075] The adhesive is a mixture of water and polyvinyl alcohol in a mass ratio of 50000:260.

[0076] Comparative Example 4

[0077] Calcium hydroxide powder with a mesh size of 325.

[0078] Testing: The carbon dioxide absorption rate of Examples 1-4 and Comparative Examples 1-4 was tested using the following methods:

[0079] A. Take 5.3g of citric acid monohydrate, 4.4g of NaHCO3, and 0.3g of activated carbon, mix them, and make them into small packets to obtain a carbon dioxide generator.

[0080] B. Weigh 2g of carbon dioxide adsorbent and one packet of carbon dioxide generator, place them in a plastic bag, seal and react.

[0081] C. Place one packet of carbon dioxide generator into another plastic bag and seal it for reaction, serving as a blank control group.

[0082] Calculate the volume difference between the two plastic bags, which is the volume of carbon dioxide adsorbed by the carbon dioxide generator. Then calculate the adsorption volume per gram of carbon dioxide adsorbent, and obtain the carbon dioxide absorption rate.

[0083]

Claims

1. A method for producing a carbon dioxide adsorbent, characterized by, The method comprises the following steps: (1) mixing zeolite, diatomite, polystyrene microsphere powder and adhesive, and rolling to form balls with a diameter of 1-1.5 mm; (2) drying the balls prepared in step (1) at 100-300 ℃ for 1-1.5 h to obtain honeycomb-shaped balls with a diameter of 1-1.5 mm; (3) spraying an organic amine solution to the honeycomb-shaped balls prepared in step (2) until adsorption saturation, and coating the balls with a mixture of calcium hydroxide and calcium oxide in the presence of an adhesive to form thorn balls with a diameter of 2-3 mm; (4) drying the thorn balls prepared in step (3) at 140-160 ℃ for 40-60 min to obtain a carbon dioxide adsorbent; The mass ratio of the mixture of calcium hydroxide and calcium oxide in step (3) is (92-95):(5-8).

2. The method for producing a carbon dioxide adsorbent according to claim 1, characterized by, The particle size of the polystyrene microsphere powder in step (1) is 100-200 mesh.

3. The method for preparing the carbon dioxide adsorbent according to claim 1, characterized in that, The mixing mass ratio of the zeolite, diatomite and polystyrene microsphere powder in step (1) is (50-70):(10-30):(10-30).

4. The method of claim 1, wherein the carbon dioxide adsorbent is prepared by a process comprising: The amount of the adhesive in step (1) is 25%-35% of the total mass of the zeolite, diatomite and polystyrene microsphere powder.

5. The method for preparing the carbon dioxide adsorbent according to claim 1, characterized in that, The organic amine in step (3) is one or more of diethanolamine, triethanolamine and N-methyl diethanolamine.

6. The method of claim 1, wherein the carbon dioxide adsorbent is prepared by a process comprising: The mass concentration of the organic amine solution in step (3) is 15%-25%.

7. The method for preparing the carbon dioxide adsorbent according to claim 1, characterized in that, The amount of the adhesive in step (3) is 25%-35% of the total mass of the calcium hydroxide and calcium oxide.

8. The method of claim 1, wherein the carbon dioxide adsorbent is prepared by a process comprising: The adhesive is a mixture of water and polyvinyl alcohol with a mass ratio of 50000:(260-350).

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