Carbon dioxide absorbent, method for preparing the same, and use thereof

Abstract

The present application provides a carbon dioxide absorbent, which comprises a carrier and an active ingredient loaded on the carrier, the carrier is a waste hydrogenation catalyst modified by an alkaline earth metal oxide, and the active ingredient comprises a carbonate of an alkali metal. The present application also provides a method for preparing a carbon dioxide absorbent. In another aspect, the present application also provides a carbon dioxide absorbent obtained by the method as described above. In another aspect, the present application also provides the use of the carbon dioxide absorbent as described above in at least one process of absorbing carbon dioxide, reducing carbon dioxide emissions and achieving a carbon neutral target. Through the above technical solutions, the present application solves the problem of waste hydrogenation catalyst recovery and disposal on the one hand, and provides a low-cost and high-efficiency carbon dioxide absorption material on the other hand.

Description

Technical Field

[0001] This invention relates to the field of materials, and more specifically, to a carbon dioxide absorbent, its preparation method, and its application. Background Technology

[0002] Carbon dioxide absorbent materials can adsorb and fix carbon dioxide generated in industrial production, thereby reducing carbon dioxide emissions. Therefore, they have important application value for achieving the goal of "carbon neutrality".

[0003] Solid adsorbents using alkali metal carbonates as the active component and porous materials as the carrier can serve as carbon dioxide absorption materials. The alkali metal carbonates can absorb carbon dioxide at 50–100°C in the presence of water vapor, generating bicarbonate. At 120–300°C, the solid material that has absorbed carbon dioxide decomposes, releasing carbon dioxide and thus achieving regeneration and recycling. A wide range of porous materials can be selected as the carrier, including activated carbon, alumina, molecular sieves, and silica aerogels. This solid adsorbent can be used in various scenarios, such as carbon dioxide capture in flue gas from wet desulfurization processes in coal-fired power plants and flue gas from natural gas power plants.

[0004] CN108295802A discloses a potassium-based CO2 absorbent particle, which includes an active component and a carrier; the active component is potassium carbonate, and the carrier is activated alumina, calcium aluminate cement, kaolin, or aluminum hydroxide; the potassium-based CO2 absorbent particle is a spherical particle, which can be used to remove CO2 from coal-fired flue gas.

[0005] However, the test results showed that the carbon dioxide absorption efficiency of existing carbon dioxide absorption materials still needs to be further improved. Summary of the Invention

[0006] The purpose of this invention is to further improve the carbon dioxide absorption efficiency of carbon dioxide absorption materials.

[0007] To achieve the above objectives, the present invention provides a carbon dioxide absorbent comprising a support and an active ingredient supported on the support, wherein the support is a waste hydrogenation catalyst modified with alkaline earth metal oxides, and the active ingredient comprises an alkali metal carbonate; the content of the active ingredient is 10-40 wt% based on the total weight of the carbon dioxide absorbent; and the content of the alkaline earth metal oxide is 0.5-10 wt% based on the weight of the waste hydrogenation catalyst modified with alkaline earth metal oxides.

[0008] On the other hand, the present invention also provides a method for preparing a carbon dioxide absorbent, the method comprising the following steps: first impregnating a waste hydrogenation catalyst with a first impregnation solution containing an alkaline earth metal element and performing a first solid-liquid separation to obtain a first impregnated waste hydrogenation catalyst; first drying and first calcining the first impregnated waste hydrogenation catalyst to obtain an alkaline earth metal oxide modified waste hydrogenation catalyst; second impregnating the alkaline earth metal oxide modified waste hydrogenation catalyst as a support with a second impregnation solution containing an active ingredient and performing a second solid-liquid separation to obtain a second impregnated support, wherein the active ingredient is an alkali metal carbonate and / or an alkali metal bicarbonate; and second drying and second calcining the second impregnated support to obtain a second calcined material; wherein, relative to 100 parts by weight of the waste hydrogenation catalyst, the amount of the alkaline earth metal element, calculated as oxide, is 0.5-10 parts by weight; and relative to 100 parts by weight of the support, the amount of the active ingredient is 10-40 parts by weight.

[0009] On the other hand, the present invention also provides a carbon dioxide absorbent obtained by the method described above.

[0010] On the other hand, the present invention also provides the application of the carbon dioxide absorbent as described above in at least one of the processes of absorbing carbon dioxide, reducing carbon dioxide emissions, and achieving carbon neutrality.

[0011] Through the above technical solution, this invention utilizes the promoting effect of alkaline earth metal oxide modification and the metal deposited on the spent hydrogenation catalyst during the hydrogenation process on CO2 adsorption, which helps to improve the carbon dioxide absorption efficiency. It is particularly suitable as a carrier for the preparation of carbon dioxide absorption materials with alkali metal carbonates as the active component. This solves the problem of recycling and treating spent hydrogenation catalysts and provides a low-cost, high-efficiency carbon dioxide absorption material. The absorbent preparation method of this invention is simple, the carrier is derived from spent hydrogenation catalysts, the cost is low, and it has significant environmental benefits, making it highly valuable for application.

[0012] Other features and advantages of the present invention will be described in detail in the following detailed description section. Detailed Implementation

[0013] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0014] This invention provides a carbon dioxide absorbent comprising a support and an active ingredient loaded on the support. The support is a waste hydrogenation catalyst modified with alkaline earth metal oxides, and the active ingredient comprises an alkali metal carbonate. Based on the total weight of the carbon dioxide absorbent, the content of the active ingredient is 10-40 wt%; based on the weight of the waste hydrogenation catalyst modified with alkaline earth metal oxides, the content of the alkaline earth metal oxides is 0.5-10 wt%.

[0015] Preferably, the content of the active ingredient is 20-30 wt% based on the total weight of the carbon dioxide absorbent; and the content of the alkaline earth metal oxide is 1-8 wt% based on the weight of the alkaline earth metal oxide-modified waste hydrogenation catalyst.

[0016] Optionally, the spent hydrogenation catalyst comprises an alumina support and a metal component, wherein the metal component includes a hydrogenation-active metal component supported on a fresh hydrogenation catalyst and metal impurities deposited on the alumina support during hydrogenation; based on the total amount of the spent hydrogenation catalyst, the content of metal impurities deposited on the alumina support during hydrogenation is 1-20 wt%, preferably 3-15 wt%; the spent hydrogenation catalyst is a spent hydrogenation catalyst that has undergone carbonization and pore-expansion treatment, wherein the pore volume of the spent hydrogenation catalyst after carbonization and pore-expansion treatment is 0.2-1.0 mL / g, preferably 0.3-0.8 mL / g, and the specific surface area is 50-300 m². 2 / g, preferably 100-200m 2 / g, with a most probable pore size of 5-15nm, preferably 8-12nm, and a carbon content of less than 3% by weight, preferably less than 1% by weight.

[0017] Optionally, the alkaline earth metal oxide is at least one of magnesium oxide, beryllium oxide, calcium oxide, strontium oxide, and barium oxide.

[0018] Optionally, the alkali metal carbonate is at least one of potassium carbonate and sodium carbonate.

[0019] Optionally, the metallic impurities deposited on the alumina support during hydrogenation include at least one of nickel, vanadium, calcium, and iron. Typically, nickel, vanadium, calcium, and iron all deposit during hydrogenation; therefore, in most cases, the metallic impurities deposited on the alumina support during hydrogenation include nickel, vanadium, calcium, and iron.

[0020] Optionally, the fresh hydrogenation catalyst corresponding to the spent hydrogenation catalyst contains a hydrogenation-active metal component, which includes at least one Group VIB metal element and at least one Group VIII metal element; preferably, the Group VIB metal element is molybdenum and / or tungsten; preferably, the Group VIII metal element is nickel and / or cobalt. Based on the total amount of the fresh hydrogenation catalyst, the content of the Group VIB metal component, calculated as oxide, is 0.2-30% by weight, preferably 1-20% by weight; the content of the Group VIII metal element, calculated as oxide, is 0.1-10% by weight, preferably 0.3-8% by weight.

[0021] Optionally, based on the total amount of the spent hydrogenation catalyst, the metallic impurities deposited on the alumina support during the hydrogenation process include 0.5-14 wt% Ni, 0.5-15 wt% V, 0.1-3 wt% Fe, and 0.1-2 wt% Ca.

[0022] The present invention also provides a method for preparing a carbon dioxide absorbent, the method comprising the following steps: first impregnating a waste hydrogenation catalyst with a first impregnation solution containing an alkaline earth metal element and performing a first solid-liquid separation to obtain a first impregnated waste hydrogenation catalyst; first drying and first calcining the first impregnated waste hydrogenation catalyst to obtain an alkaline earth metal oxide modified waste hydrogenation catalyst; second impregnating the alkaline earth metal oxide modified waste hydrogenation catalyst as a support with a second impregnation solution containing an active ingredient and performing a second solid-liquid separation to obtain a second impregnated support, wherein the active ingredient is an alkali metal carbonate and / or an alkali metal bicarbonate; and second drying and second calcining the second impregnated support to obtain a second calcined material; wherein, relative to 100 parts by weight of the waste hydrogenation catalyst, the amount of the alkaline earth metal element, calculated as oxide, is 0.5-10 parts by weight; and relative to 100 parts by weight of the support, the amount of the active ingredient is 10-40 parts by weight.

[0023] The material after the second roasting can be used as a carbon dioxide absorbent.

[0024] Preferably, the amount of alkaline earth metal element is 1-8 parts by weight, based on oxides, per 100 parts by weight of the waste hydrogenation catalyst; and the amount of active ingredient is 20-30 parts by weight, per 100 parts by weight of the support.

[0025] Wherein, the first impregnation and the second impregnation are each independently an equal-volume saturated impregnation, an unsaturated impregnation, or a supersaturated impregnation.

[0026] Optionally, the conditions for the first drying include: a temperature of 80-150°C and a time of 2-8 hours.

[0027] Optionally, the conditions for the first calcination include: a temperature of 200-600℃ and a time of 2-8 hours.

[0028] Optionally, the conditions for the second drying include: a temperature of 80-120°C and a time of 2-8 hours.

[0029] Optionally, the conditions for the second calcination include: a temperature of 120-200℃ and a time of 2-8 hours.

[0030] Optionally, the spent hydrogenation catalyst comprises an alumina support and a metal component, wherein the metal component includes a hydrogenation-active metal component supported on a fresh hydrogenation catalyst and metal impurities deposited on the alumina support during hydrogenation; based on the total amount of the spent hydrogenation catalyst, the content of metal impurities deposited on the alumina support during hydrogenation is 1-20 wt%, preferably 3-15 wt%; the spent hydrogenation catalyst is a spent hydrogenation catalyst that has undergone carbonization and pore-expansion treatment, wherein the pore volume of the spent hydrogenation catalyst after carbonization and pore-expansion treatment is 0.2-1.0 mL / g, preferably 0.3-0.8 mL / g, and the specific surface area is 50-300 m². 2 / g, preferably 100-200m 2 / g, with a most probable pore size of 5-15nm, preferably 8-12nm, and a carbon content of less than 3% by weight, preferably less than 1% by weight.

[0031] Optionally, the first impregnation solution contains at least one of magnesium nitrate, beryllium nitrate, calcium nitrate, strontium nitrate, and barium nitrate.

[0032] Optionally, the second impregnation solution contains at least one of potassium carbonate, potassium bicarbonate, sodium carbonate, and sodium bicarbonate.

[0033] Optionally, the metal deposited on the alumina support during hydrogenation includes at least one of nickel, vanadium, calcium, and iron. Typically, nickel, vanadium, calcium, and iron all deposit during hydrogenation; therefore, in most cases, the metal impurities deposited on the alumina support during hydrogenation include nickel, vanadium, calcium, and iron.

[0034] Optionally, the fresh hydrogenation catalyst corresponding to the spent hydrogenation catalyst contains a hydrogenation-active metal component, which includes at least one Group VIB metal element and at least one Group VIII metal element; preferably, the Group VIB metal element is molybdenum and / or tungsten; preferably, the Group VIII metal element is nickel and / or cobalt. Based on the total amount of the fresh hydrogenation catalyst, the content of the Group VIB metal component, calculated as oxide, is 0.2-30% by weight, preferably 1-20% by weight; the content of the Group VIII metal element, calculated as oxide, is 0.1-10% by weight, preferably 0.3-8% by weight.

[0035] Optionally, based on the total amount of the spent hydrogenation catalyst, the metallic impurities deposited on the alumina support during the hydrogenation process include 0.5-14 wt% Ni, 0.5-15 wt% V, 0.1-3 wt% Fe, and 0.1-2 wt% Ca.

[0036] Optionally, the method further includes: subjecting the waste hydrogenation catalyst that has not undergone carbonization and pore-expansion treatment to carbonization and pore-expansion treatment to obtain the waste hydrogenation catalyst that has undergone carbonization and pore-expansion treatment.

[0037] Optionally, the charring and pore-expanding process includes a first heat treatment, a second heat treatment, and a third heat treatment performed sequentially in an oxygen-containing atmosphere; wherein the oxygen content in the oxygen-containing atmosphere is 8-30% by volume, preferably 10-25%.

[0038] Optionally, the conditions for the first heat treatment include: a temperature of 100-250°C and a time of 1-5 hours.

[0039] Optionally, the conditions for the second heat treatment include: a temperature of 300-450°C and a time of 1-5 hours.

[0040] Optionally, the conditions for the third heat treatment include: a temperature of 500-800℃ and a time of 1-5 hours.

[0041] Preferably, the conditions for the first heat treatment include: treatment at a temperature of 150-200°C for 1-3 hours; the conditions for the second heat treatment include: treatment at a temperature of 350-420°C for 1-3 hours; and the conditions for the third heat treatment include: treatment at a temperature of 600-750°C for 1-3 hours.

[0042] Optionally, the source of the waste hydrotreating catalyst that has not undergone carbonization and pore-expansion treatment includes at least one of waste gasoline hydrotreating catalyst, waste diesel hydrotreating catalyst, waste kerosene hydrotreating catalyst, waste wax oil hydrotreating catalyst, and waste residue oil hydrotreating catalyst. Preferably, the source of the waste hydrotreating catalyst that has not undergone carbonization and pore-expansion treatment includes waste residue oil hydrotreating catalyst, which contains more vanadium, making it more conducive to carbon dioxide absorption.

[0043] Optionally, the spent hydrogenation catalyst that has not undergone carbonization and pore-expansion treatment has a pore volume of 0.02-0.8 mL / g and a specific surface area of ​​10-200 m². 2 / g, with a most probable pore diameter of 1-15nm; more preferably, the pore volume of the untreated spent hydrogenation catalyst is 0.02-0.5mL / g, and the specific surface area is 50-200m². 2 / g, with a most probable pore size of 3-10nm.

[0044] The present invention also provides a carbon dioxide absorbent obtained by the method described above.

[0045] The present invention also provides the application of the carbon dioxide absorbent in at least one of the processes of absorbing carbon dioxide, reducing carbon dioxide emissions, and achieving carbon neutrality.

[0046] For example, carbon dioxide absorbent can be used in flue gas treatment devices to absorb carbon dioxide in flue gas. After carbon dioxide absorption saturation, carbon dioxide can be released through heating to regenerate the carbon dioxide absorbent. The regenerated carbon dioxide absorbent can then be used again to absorb carbon dioxide in flue gas.

[0047] The present invention will be further described in detail below through embodiments. Unless otherwise specified, the raw materials used in the embodiments are all commercially available.

[0048] Example 1

[0049] Weigh 100g of waste oil hydrogenation catalyst (with 6.0wt% Fe, Ca, Ni, V, and other metal deposits on the alumina support during hydrogenation, a pore volume of 0.25mL / g, and a specific surface area of ​​128m²). 2 The catalyst, with a pore size of 5 nm and a corresponding active metal composition of 15 wt% MoO3 and 5 wt% NiO, was calcined in air using a programmed temperature rise method. The temperature was increased from room temperature to 150 °C and held for 2 hours, then increased to 350 °C and held for 2 hours, and finally increased to 600 °C and held for 3 hours. This yielded a spent hydrogenation catalyst after charring and pore expansion treatment (pore volume 0.41 mL / g, specific surface area 152 m² / g). 2 / g, with a maximum pore size of 9nm). 50g of the calcined waste hydrogenation catalyst was weighed, impregnated in a solution containing 9.7g magnesium nitrate for 1 hour, dried at 120℃ for 3 hours, and then calcined at 300℃ for 3 hours to obtain magnesium oxide-modified waste hydrogenation catalyst. 50g of the magnesium oxide-modified waste hydrogenation catalyst was weighed, impregnated in an aqueous solution containing 12.5g potassium carbonate for 1 hour, dried at 120℃ for 3 hours, and then calcined at 200℃ for 3 hours to obtain carbon dioxide solid absorbent X-1.

[0050] Example 2

[0051] Weigh 100g of waste oil hydrogenation catalyst (the amount of Fe, Ca, Ni, V and other metals deposited on the alumina support during the hydrogenation process is 4.2wt%, the pore volume is 0.22mL / g, and the specific surface area is 106m²). 2 The catalyst, with a pore size of 4 nm and a corresponding active metal component for hydrogenation of 10 wt% MoO3 and 3 wt% CoO, was calcined in air using a programmed temperature rise method. The temperature was increased from room temperature to 200 °C and held for 2 hours, then increased to 400 °C and held for 2 hours, and finally increased to 600 °C and held for 3 hours. This yielded a spent hydrogenation catalyst after charring and pore expansion treatment (pore volume 0.34 mL / g, specific surface area 138 m²). 2 / g, with a maximum pore size of 8nm). 50g of the calcined waste hydrogenation catalyst was weighed, impregnated in a solution containing 1.8g magnesium nitrate for 1 hour, dried at 120℃ for 3 hours, and then calcined at 300℃ for 3 hours to obtain magnesium oxide-modified waste hydrogenation catalyst. 50g of the magnesium oxide-modified waste hydrogenation catalyst was weighed, impregnated in an aqueous solution containing 8.8g potassium carbonate for 1 hour, dried at 120℃ for 3 hours, and then calcined at 200℃ for 3 hours to obtain carbon dioxide solid absorbent X-2.

[0052] Example 3

[0053] Weigh 100g of waste oil hydrogenation catalyst (the amount of metals such as Fe, Ca, Ni, and V deposited on the alumina support during the hydrogenation process is 9.6wt%, the pore volume is 0.15mL / g, and the specific surface area is 74m²). 2 The catalyst, with a pore size of 4 nm and a corresponding active metal component for hydrogenation of 20 wt% MoO3 and 8 wt% NiO, was calcined in air using a programmed temperature rise method. The temperature was increased from room temperature to 200 °C and held for 2 hours, then increased to 400 °C and held for 2 hours, and finally increased to 600 °C and held for 3 hours. This yielded a spent hydrogenation catalyst after charring and pore expansion treatment (pore volume 0.38 mL / g, specific surface area 146 m²). 2 / g, with a maximum pore size of 8nm). 50g of the calcined waste hydrogenation catalyst was weighed, impregnated in a solution containing 16.0g magnesium nitrate for 1 hour, dried at 120℃ for 3 hours, and then calcined at 300℃ for 3 hours to obtain magnesium oxide-modified waste hydrogenation catalyst. 50g of the magnesium oxide-modified waste hydrogenation catalyst was weighed, impregnated in an aqueous solution containing 21.4g potassium carbonate for 1 hour, dried at 120℃ for 3 hours, and then calcined at 200℃ for 3 hours to obtain carbon dioxide solid absorbent X-3.

[0054] Comparative Example 1

[0055] Weigh 100g of waste oil hydrogenation catalyst (Fe, Ca, Ni, V, etc. metal deposition amount 6wt%, pore volume 0.25mL / g, specific surface area 128m²). 2 The catalyst, with a pore size of 5 nm and a corresponding active metal composition of 15 wt% MoO3 and 5 wt% NiO, was calcined in air using a programmed temperature rise method. The temperature was increased from room temperature to 150 °C and held for 2 hours, then increased to 350 °C and held for 2 hours, and finally increased to 600 °C and held for 3 hours. This yielded a spent hydrogenation catalyst after charring and pore expansion treatment (pore volume 0.41 mL / g, specific surface area 152 m² / g). 2 / g, with the most probable pore diameter being 9nm). Weigh 50g of the calcined waste hydrogenation catalyst, impregnate it in an aqueous solution containing 12.5g of potassium carbonate for 1 hour, dry it at 120℃ for 3 hours, and calcine it at 200℃ for 3 hours to obtain carbon dioxide solid absorbent DX-1.

[0056] Comparative Example 2

[0057] 50g of fresh industrial alumina carrier (free from metals deposited during hydrogenation and hydrogenation-active metal components) was weighed and impregnated in a solution containing 9.7g of magnesium nitrate for 1 hour. After drying at 120℃ for 3 hours, it was calcined at 300℃ for 3 hours to obtain magnesium oxide-modified alumina carrier. Another 50g of magnesium oxide-modified alumina carrier was weighed and impregnated in an aqueous solution containing 12.5g of potassium carbonate for 1 hour. After drying at 120℃ for 3 hours, it was calcined at 200℃ for 3 hours to obtain carbon dioxide solid absorbent DX-2.

[0058] Comparative Example 3

[0059] 50g of fresh residue hydrotreating catalyst (containing only the active metal components for hydrotreating, excluding metals deposited during hydrotreating, including 15wt% MoO3 and 5wt% NiO) was weighed, impregnated in a solution containing 9.7g magnesium nitrate for 1 hour, dried at 120℃ for 3 hours, and then calcined at 300℃ for 3 hours to obtain a magnesium oxide-modified residue hydrotreating catalyst. Another 50g of the magnesium oxide-modified residue hydrotreating catalyst was weighed, impregnated in an aqueous solution containing 12.5g potassium carbonate for 1 hour, dried at 120℃ for 3 hours, and then calcined at 200℃ for 3 hours to obtain carbon dioxide solid absorbent DX-3.

[0060] Comparative Example 4

[0061] Weigh 50g of alumina carrier (which does not contain metal deposited during hydrogenation or hydrogenation active metal components), immerse it in an aqueous solution containing 12.5g of potassium carbonate for 1 hour, dry it at 120℃ for 3 hours, and calcine it at 200℃ for 3 hours to obtain carbon dioxide solid absorbent DX-4.

[0062] Comparative Example 5

[0063] Weigh 50g of fresh residue oil hydrogenation catalyst (containing no metal deposited during hydrogenation, but only the active metal components for hydrogenation, including 15wt% MoO3 and 5wt% NiO), impregnate it in an aqueous solution containing 12.5g potassium carbonate for 1 hour, dry it at 120℃ for 3 hours, and calcine it at 200℃ for 3 hours to obtain carbon dioxide solid absorbent DX-5.

[0064] Test Example 1

[0065] The method described in the reference (Energy Fuels 2011, 25, 5528-5537) was modified. CO2 adsorption was measured using a chemisorption analyzer. The solid adsorbent was saturated with water vapor at room temperature (more than 24 h). Then, 0.2 g of the solid adsorbent was weighed into a U-shaped quartz tube, installed in a heating furnace, and pretreated under an Ar atmosphere. Then, a CO2 / Ar mixed gas was introduced at 50 °C to allow the solid adsorbent to adsorb CO2 until saturation. Then, the atmosphere was switched to Ar to purge for 20 min. Then, the temperature was programmed to increase from 50 °C to 500 °C at a rate of 10 °C / min. At the same time, the desorbed CO2 signal was collected by mass spectrometry. Following the method described above, the carbon dioxide solid absorbents of Examples 1-3 and Comparative Examples 1-5 were tested for weak CO2 adsorption capacity, strong CO2 adsorption capacity, and total CO2 adsorption capacity. The amount of CO2 desorbed at 100-250℃ (KHCO3 decomposition temperature) was defined as weak CO2 adsorption capacity, and the amount of CO2 desorbed at 250-350℃ (KAlCO3(OH)2 decomposition temperature) was defined as strong CO2 adsorption capacity. The sum of these two values ​​was the total CO2 adsorption capacity. The results are shown in Table 1.

[0066] Table 1

[0067]

[0068] As can be seen from the results in Table 1, when the content of active ingredient K2CO3 is the same, the CO2 adsorption capacity (especially the strong CO2 adsorption capacity) of the CO2 absorbing material provided by the present invention is significantly higher than that of the comparative example.

[0069] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0070] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0071] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A carbon dioxide absorbent, characterized in that, The carbon dioxide absorbent comprises a support and an active component loaded on the support. The support is a waste hydrogenation catalyst modified with alkaline earth metal oxides, and the active component comprises alkali metal carbonates. Based on the total weight of the carbon dioxide absorbent, the content of the active component is 10-40 wt%; based on the weight of the waste hydrogenation catalyst modified with alkaline earth metal oxides, the content of the alkaline earth metal oxides is 0.5-10 wt%. The spent hydrogenation catalyst includes an alumina support and a metal component, wherein the metal component includes a hydrogenation active metal component supported on a fresh hydrogenation catalyst and metal impurities deposited on the alumina support during the hydrogenation process. The alkali metal carbonate is at least one of potassium carbonate and sodium carbonate. The metallic impurities deposited on the alumina support during the hydrogenation process include at least one of nickel, vanadium, calcium, and iron. The hydrogenation active metal component includes at least one Group VIB metal element and at least one Group VIII metal element; based on the total amount of the fresh hydrogenation catalyst, the content of the Group VIB metal component, calculated as oxide, is 0.2-30% by weight; the content of the Group VIII metal element, calculated as oxide, is 0.1-10% by weight.

2. The carbon dioxide absorbent according to claim 1, wherein, Based on the total weight of the carbon dioxide absorbent, the content of the active ingredient is 20-30 wt%; based on the weight of the alkaline earth metal oxide modified waste hydrogenation catalyst, the content of the alkaline earth metal oxide is 1-8 wt%.

3. The carbon dioxide absorbent according to claim 1 or 2, wherein, Based on the total amount of the spent hydrogenation catalyst, the content of metallic impurities deposited on the alumina support during the hydrogenation process is 1-20 wt%. The spent hydrogenation catalyst is a spent hydrogenation catalyst that has undergone carbonization and pore-expansion treatment. The pore volume of the spent hydrogenation catalyst after carbonization and pore-expansion treatment is 0.2-1.0 mL / g, and the specific surface area is 50-300 m². 2 / g, with a most probable pore size of 5-15 nm and a carbon content of less than 3wt%; The alkaline earth metal oxide is at least one of magnesium oxide, beryllium oxide, calcium oxide, strontium oxide, and barium oxide.

4. The carbon dioxide absorbent according to claim 3, wherein, Based on the total amount of the spent hydrogenation catalyst, the content of metallic impurities deposited on the alumina support during the hydrogenation process is 3-15 wt%; the spent hydrogenation catalyst is a spent hydrogenation catalyst that has undergone carbonization and pore-expansion treatment, and the pore volume of the spent hydrogenation catalyst after carbonization and pore-expansion treatment is 0.3-0.8 mL / g, and the specific surface area is 100-200 m². 2 / g, with a most probable pore size of 8-12 nm and a carbon content of less than 1 wt%.

5. A method for preparing a carbon dioxide absorbent, characterized in that, The method includes the following steps: The spent hydrogenation catalyst was first impregnated with a first impregnation solution containing alkaline earth metal elements and then subjected to a first solid-liquid separation to obtain the spent hydrogenation catalyst after the first impregnation. The first impregnated waste hydrogenation catalyst is subjected to a first drying and a first calcination to obtain an alkaline earth metal oxide modified waste hydrogenation catalyst. The waste hydrogenation catalyst modified with alkaline earth metal oxide is used as a support and is impregnated with a second impregnation solution containing active components and then subjected to a second solid-liquid separation to obtain the second impregnated support. The active components are alkali metal carbonates and / or alkali metal bicarbonates. The second impregnated carrier is subjected to a second drying and a second calcination to obtain the second calcined material; The spent hydrogenation catalyst includes an alumina support and a metal component, wherein the metal component includes a hydrogenation active metal component supported on a fresh hydrogenation catalyst and metal impurities deposited on the alumina support during the hydrogenation process. Wherein, relative to every 100 parts by weight of the spent hydrogenation catalyst, the amount of the alkaline earth metal element, calculated as oxide, is 0.5-10 parts by weight; relative to every 100 parts by weight of the support, the amount of the active ingredient is 10-40 parts by weight. The second impregnation solution contains at least one of potassium carbonate, potassium bicarbonate, sodium carbonate, and sodium bicarbonate. The metallic impurities deposited on the alumina support during the hydrogenation process include at least one of nickel, vanadium, calcium, and iron.

6. The method according to claim 5, wherein, The amount of alkaline earth metal element, calculated as oxide, is 1-8 parts by weight relative to 100 parts by weight of the spent hydrogenation catalyst; the amount of active ingredient, calculated as oxide, is 20-30 parts by weight relative to 100 parts by weight of the support.

7. The method according to claim 5 or 6, wherein, The first impregnation and the second impregnation are each independently an equal-volume saturated impregnation, an unsaturated impregnation, or a supersaturated impregnation; The conditions for the first drying include: a temperature of 80-150℃ and a time of 2-8 hours; The conditions for the first roasting include: a temperature of 200-600℃ and a time of 2-8 hours; The conditions for the second drying include: a temperature of 80-120°C and a time of 2-8 hours; The conditions for the second roasting include: a temperature of 120-200℃ and a time of 2-8 hours.

8. The method according to claim 5 or 6, wherein, Based on the total amount of the spent hydrogenation catalyst, the content of metallic impurities deposited on the alumina support during the hydrogenation process is 1-20 wt%. The spent hydrogenation catalyst is a spent hydrogenation catalyst that has undergone carbonization and pore-expansion treatment. The pore volume of the spent hydrogenation catalyst after carbonization and pore-expansion treatment is 0.2-1.0 mL / g, and the specific surface area is 50-300 m². 2 / g, with a most probable pore size of 5-15 nm and a carbon content of less than 3wt%; The first impregnation solution contains at least one of magnesium nitrate, beryllium nitrate, calcium nitrate, strontium nitrate, and barium nitrate.

9. The method according to claim 8, wherein, Based on the total amount of the spent hydrogenation catalyst, the content of metallic impurities deposited on the alumina support during the hydrogenation process is 3-15 wt%; the spent hydrogenation catalyst is a spent hydrogenation catalyst that has undergone carbonization and pore-expansion treatment, and the pore volume of the spent hydrogenation catalyst after carbonization and pore-expansion treatment is 0.3-0.8 mL / g, and the specific surface area is 100-200 m². 2 / g, with a most probable pore size of 8-12nm and a carbon content of less than 1wt%.

10. The method according to claim 8, wherein, The method also includes: subjecting the waste hydrogenation catalyst that has not undergone carbonization and pore-expansion treatment to carbonization and pore-expansion treatment to obtain the waste hydrogenation catalyst that has undergone carbonization and pore-expansion treatment; The charring and pore-expanding processes include a first heat treatment, a second heat treatment, and a third heat treatment performed sequentially in an oxygen-containing atmosphere; the oxygen content in the oxygen-containing atmosphere is 8-30% by volume. The conditions for the first heat treatment include: a temperature of 100-250℃ and a time of 1-5 hours; The conditions for the second heat treatment include: a temperature of 300-450℃ and a time of 1-5 hours; The conditions for the third heat treatment include: a temperature of 500-800℃ and a time of 1-5 hours; The sources of the waste hydrogenation catalysts that have not undergone carbonization and pore-expansion treatment include at least one of waste gasoline hydrogenation catalysts, waste diesel hydrogenation catalysts, waste coal tar hydrogenation catalysts, waste wax oil hydrogenation catalysts, and waste residue oil hydrogenation catalysts.

11. The method according to claim 10, wherein, In the oxygen-containing atmosphere, the volume content of oxygen is 10-25%; The conditions for the first heat treatment include: treatment at a temperature of 150-200℃ for 1-3 hours; The conditions for the second heat treatment include: treatment at a temperature of 350-420°C for 1-3 hours; The conditions for the third heat treatment include: treatment at a temperature of 600-750℃ for 1-3 hours; The sources of the waste hydrogenation catalyst that has not undergone carbonization and pore-expansion treatment include waste residue oil hydrogenation catalyst; The spent hydrogenation catalyst, which has not undergone carbonization and pore-expansion treatment, has a pore volume of 0.02-0.8 mL / g and a specific surface area of ​​10-200 m². 2 / g, with the most probable pore diameter being 1-15 nm.

12. The method according to claim 11, wherein, The spent hydrogenation catalyst, which has not undergone carbonization and pore-expansion treatment, has a pore volume of 0.02-0.5 mL / g and a specific surface area of ​​50-200 m². 2 / g, with a most probable pore size of 3-10nm.

13. The carbon dioxide absorbent obtained by the method of any one of claims 5-12.

14. The use of the carbon dioxide absorbent according to any one of claims 1-4 and 13 in the absorption of carbon dioxide.

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