Method for mineralizing co 2 in gas

Abstract

Provided in the present application is a method for mineralizing CO2 in a gas. The method comprises the following steps: using a mineralization raw material to mineralize CO2 in a gas; and during mineralization, performing surface renewal on the mineralization raw material according to a predetermined renewal frequency, wherein the renewal frequency is determined according to a function relationship between physical property parameters of the mineralization raw material and physical property parameters of the gas. In the present application, a function relationship between property parameters of a mineralization raw material, property parameters of a gas to be mineralized and the surface renewal frequency of the mineralization raw material is established, and surface renewal is performed on the mineralization raw material according to a calculated frequency, thereby increasing the CO2 absorption rate of the mineralization raw material, and improving the utilization rate of CO2-fixable components in the mineralization raw material.

Description

A method for removing CO2 from mineralized gases This application claims priority to Chinese Patent Application No. 202411195542.9, filed on August 28, 2024, entitled "A Method for Dissolving CO2 in Mineralized Gas", the entire contents of which are incorporated herein by reference. Technical Field

[0001] This invention relates to the field of CO2 treatment technology, and more particularly to a method for treating CO2 in mineralized gases. Background Technology

[0002] To reduce atmospheric CO2, the mainstream methods of Direct Air Capture (DAC) employ solution absorption and solid adsorption. Chemical absorption processes based on ethanolamine organic amine solutions have been widely used in flue gas capture. However, the high gas throughput and low liquid-to-gas ratio of DAC lead to problems such as significant amine volatilization, substantial gas-phase losses, and a substantial increase in capture costs. Solid adsorption technology can effectively address the issues of amine volatilization and water loss. Solid adsorbents mainly include alkali / alkaline earth metal-based adsorbents, metal-organic framework adsorbents, supported amine adsorbents, and humidifying adsorbents, but they still suffer from high energy consumption and high costs. Furthermore, DAC technology only captures CO2 from the air. To achieve stable CO2 sequestration, i.e., to reach the goal of "carbon neutrality," the current approach is to transport the captured carbon dioxide and then inject it into specific geological structures for storage. However, such operations are difficult to monitor, pose a risk of contaminating groundwater beneath the geological layers, and the damage to geological structures could trigger seismic activity and secondary leakage of high-concentration CO2.

[0003] Direct air mineralization (DAM) involves directly mineralizing CO2 from the air into stable carbonate structures using mineralizing materials containing calcium, magnesium, etc., without requiring CO2 capture or concentration. For example, existing technologies disclose the use of industrial solid waste to mineralize CO2 from the air; however, the utilization rate of raw materials such as industrial solid waste or alkali metal minerals in currently disclosed methods is relatively low. Summary of the Invention

[0004] In view of this, the present invention provides a method for mineralizing CO2 in a gas. The method provided by the present invention directly uses mineral raw materials to directly mineralize CO2 in the gas into a stable carbonate structure, and can improve the utilization rate of the CO2-fixable components in the mineral raw materials.

[0005] This application provides a method for mineralizing CO2 in a gas, comprising the following steps:

[0006] The CO2 in the gas is mineralized using mineralized raw materials, and the surface of the mineralized raw materials is renewed at a predetermined renewal frequency during the mineralization process.

[0007] The update frequency is determined according to the functional relationship between the physical property parameters of the mineralized raw material and the physical property parameters of the gas;

[0008] The physical property parameters of the mineralized raw material include the moisture content S. w The content of CO2-fixable components in mineral raw materials (w) t At least one of the following: %, bulk density ρ of the mineralized raw material, and particle size d of the mineralized raw material;

[0009] The physical properties of the gas include the partial pressure of CO2 in the gas. and the absolute humidity R of the gas w At least one of them.

[0010] The applicant discovered in the research that the physical property parameters of the mineralized raw materials, including the moisture content S, are important parameters. w The content of CO2-fixable components in mineral raw materials (w) t The physical properties of the gas to be mineralized, including the bulk density ρ and particle size d of the mineralized raw material, as well as the partial pressure of CO2 in the gas, are also considered. and the absolute humidity R of the gas w These factors can affect the absorption rate of CO2 by mineralized raw materials, thereby affecting the utilization rate of CO2-fixable components in the mineralized raw materials. Based on this, the applicant established a functional relationship between the above performance parameters and the surface renewal frequency of the mineralized raw materials, and carried out surface renewal of the mineralized raw materials according to the calculated frequency, thereby improving the absorption rate of CO2 by the mineralized raw materials and improving the utilization rate of CO2-fixable components in the mineralized raw materials.

[0011] This application employs a direct air mineralization method to mineralize CO2 in gas. Specifically, the mineralizing raw material is brought into contact with a CO2-containing gas. Ca, Mg, and other elements in the mineralizing raw material react with CO2 to form stable carbonates, thereby achieving the absorption and stable fixation of CO2. A typical reaction process is as follows:

[0012] 2Ca(Mg)X n (OH) m +2CO2=2Ca(Mg)CO3+X 2n O (m+4) +mH2O;

[0013] Where X represents other elements in mineral raw materials such as silicon, iron, and aluminum.

[0014] Based on this, the mineralized raw material described in this application is a magnesium-calcium mineralized raw material, including but not limited to industrial solid waste such as carbide slag, steel slag, red mud, and concrete, or natural minerals such as serpentine, forsterite, basalt, volcanic ash, and wollastonite. In some specific implementations, the mineralizable CO2 component in the mineralized raw material is mainly an alkaline earth metal compound such as magnesium hydroxide, calcium hydroxide, magnesium oxide, or calcium oxide. The content of the mineralizable CO2 component, calculated as calcium hydroxide, is not less than 5%, preferably 10wt% to 95wt%, more preferably 20wt% to 90wt%, and most preferably 30wt% to 85wt%. In some specific implementations, the dry weight of the mineralized raw material is 10 kg / m³. 2 ~50kg / m 2 The preferred value is 15 kg / m 2 ~45kg / m 2 More preferably 20 kg / m 2 ~40kg / m 2 In some specific implementations, the moisture content of the mineralized raw material is 2wt% to 40wt%, preferably 5wt% to 35wt%. In some specific implementations, the particle size of the mineralized raw material is 20 mesh to 2000 mesh, preferably 50 mesh to 1000 mesh, and more preferably 80 mesh to 500 mesh.

[0015] The method provided by this invention can mineralize CO2 in air, as well as waste gas, including industrial waste gas, such as CO2 in flue gas from thermal power plants, cement plants, steel plants, and chemical plants. Therefore, the gas described in this application, i.e., the gas to be mineralized, can be air or CO2-containing waste gas. In some specific implementations, the water content of the gas is 2 g / kg dry gas to 40 g / kg dry gas, preferably 5 g / kg dry gas to 35 g / kg dry gas.

[0016] This application does not impose any particular restrictions on the specific method of mineralizing CO2 in gas using mineralized raw materials; the mineralized raw materials can be directly brought into contact with the gas. In some specific implementations, to improve mineralization efficiency, gas can be introduced while the mineralized raw materials are moving. This application does not impose any particular restrictions on the method of moving the mineralized raw materials; for example, the mineralized raw materials can be loaded onto a carrier, such as a conveyor belt, and the movement of the mineralized raw materials can be achieved through the reciprocating motion of the carrier. In some specific implementations, the movement of the mineralized raw materials is translational, and the moving speed of the mineralized raw materials is preferably 0.05 m / s to 1 m / s, preferably 0.1 m / s to 0.8 m / s. While the mineralized raw materials are moving, gas is introduced to contact them, for example, the gas is introduced at a certain angle to the mineralized raw materials, such as 90°. In some specific implementations, the flow rate of the gas is 0.20 m / s to 4.00 m / s, preferably 0.50 m / s to 3.50 m / s.

[0017] This application involves updating the surface of the mineralized raw material at a predetermined frequency during the mineralization process, ensuring sufficient contact and rapid reaction between the CO2 in the gas and the mineralized raw material. Specifically, the surface updating refers to updating the surface of the mineralized raw material in contact with the gas. In some specific implementations, the surface updating method includes, but is not limited to, at least one of tumbling, stirring, scraping, vibration, blowing, rocking, sliding, and fluidization, as long as it can change the surface of the mineralized raw material in contact with the gas.

[0018] In some specific implementations, this application updates the surface of the mineralized raw material according to a predetermined update frequency. As mentioned above, the update frequency is determined according to the functional relationship between the physical property parameters of the mineralized raw material and the physical property parameters of the gas; the physical property parameters of the mineralized raw material include the moisture content S of the mineralized raw material. w The content of CO2-fixable components in mineral raw materials (w) t At least one of the following: %, bulk density ρ of the mineralized raw material, and particle size d of the mineralized raw material; the physical property parameters of the gas include the partial pressure of CO2 in the gas. and the absolute humidity R of the gas w At least one of them. This application specifies the moisture content S of the mineralized raw material. w The content of CO2-fixable components in mineral raw materials (w) t %, bulk density ρ of mineralized raw materials, particle size d of mineralized raw materials, partial pressure of CO2 in the gas and the absolute humidity R of the gas w There are no special limitations on the determination method; any method well known to those skilled in the art is acceptable. For example, the moisture content S of the mineralized raw material... w The following methods can be used to determine this:

[0019] Drying method: The mineral raw material is heated at a certain temperature to evaporate the moisture, and the moisture content is calculated by weighing the change in sample mass. The commonly used drying temperature is 105℃, and the mineral raw material is dried until its mass remains basically constant.

[0020] The content of CO2-fixable components in the mineralized raw material w t % can be determined using the following method:

[0021] Sucrose method: The basic principle of this method is to utilize the reactivity of sucrose with calcium hydroxide in water, and determine the content of calcium produced by the reaction by titration, thereby calculating the content of CO2 components that can be fixed (calculated as calcium hydroxide).

[0022] The bulk density ρ of the mineralized raw material can be determined by the following method:

[0023] Vibration compaction method: Vibration compaction method is a commonly used method for bulk density testing. It uses a vibratory compactor to compact materials under certain conditions to obtain the bulk density of mineral raw materials.

[0024] The particle size d of the mineralized raw material can be determined by the following method:

[0025] Sieving method: The sieving method is one of the most commonly used traditional particle size testing methods. It determines the distribution of particles within different size ranges by sieving particulate material through a series of sieves with different aperture sizes.

[0026] The partial pressure of CO2 in the gas The following methods can be used to determine this:

[0027] Dalton's law of partial pressure: According to Calculate the partial pressure of CO2 in the gas. in P is the mole fraction of CO2. total This represents the total pressure of the gas.

[0028] The absolute humidity R of the gas w The following methods can be used to determine this:

[0029] Wet-bulb and dry-bulb method: This is a common method for measuring absolute humidity. It uses the relationship between the heat required for water vapor to evaporate from a gas and the relative humidity of the gas to calculate the absolute humidity value.

[0030] In some specific implementations, when gas is introduced for mineralization under conditions of moving mineral raw materials, the mineral raw materials have a moving velocity, and the gas has a flowing velocity. The moving velocity of the mineral raw materials and the flowing velocity of the gas also affect the absorption rate of CO2 by the mineral raw materials. Based on this, the physical property parameters of the mineral raw materials selected in this application, besides the moisture content S, are... w The content of CO2-fixable components in mineral raw materials (w) t The percentage, bulk density ρ of the mineralized raw material, particle size d of the mineralized raw material, and also the moving velocity u of the mineralized raw material. s The physical property parameters of the gas selected in this application, except for the partial pressure of CO2 in the gas... absolute humidity R of a gas w It also includes the gas flow velocity, i.e., the gas flow rate u. g This application specifies the movement speed u of the mineralized raw material. s and gas flow rate u g There are no special limitations on the determination method; any method well-known to those skilled in the art is acceptable. For example, the movement speed u of the mineralized raw material. s The following methods can be used to determine this:

[0031] Velocity method: An important physical quantity describing the motion of an object, representing the distance the object moves per unit time, with units of m / s (meters per second). Specifically, it can be calculated by uniformly calculating the distance moved per unit time by selecting a marker or internal standard, recording the distance moved by the marker at times t0 and t, and thus calculating the velocity.

[0032] Gas flow rate u g The following methods can be used to determine the value:

[0033] Wind speed is determined by measuring the rotational speed of a wind cup or propeller. The wind cup or propeller rotates around its axis under the influence of wind force, and its rotational speed is proportional to the wind speed.

[0034] In some specific implementations, the functional relationship between the physical property parameters of the mineralized raw material and the physical property parameters of air satisfies formula (1):

[0035]

[0036] In formula (1), F is the surface renewal frequency of the mineral raw material, with the unit being 1 / h; This is the partial pressure of CO2 in a gas, expressed in kp. a ;R w The absolute humidity of a gas, expressed in g / kg dry gas; u g S represents gas flow velocity, measured in m / s. w Moisture content of mineralized raw materials, in %; w t % represents the content of CO2-fixable components in the mineralized raw material, expressed as a percentage; ρ represents the bulk density of the mineralized raw material, expressed as kg / m³. 3 ;u s d represents the moving velocity of the mineralized raw material, in m / s; d represents the particle size of the mineralized raw material, in m.

[0037] α is the highest power coefficient of the power function of the effect of the partial pressure of CO2 in the gas on the CO2 absorption rate; β is the highest power coefficient of the power function of the effect of the gas flow rate on the CO2 absorption rate; σ is the highest power coefficient of the power function of the effect of the moving speed of the mineral raw material on the CO2 absorption rate; ψ is the highest power coefficient of the power function of the effect of the particle size of the mineral raw material on the CO2 absorption rate.

[0038] In some specific implementations, α, β, σ, and ψ satisfy formula (2):

[0039] 2α+β-σ=ψ Formula (2).

[0040] In some specific implementations, α is obtained in the following way:

[0041] After the mineral raw materials are spread out, gas is introduced under sealed conditions to carry out mineralization, establishing the partial pressure of CO2 in the gas. The value of α is obtained by determining the functional relationship between α and the CO2 absorption rate η.

[0042] The CO2 absorption rate η is calculated according to formula (3):

[0043]

[0044] In formula (3), η is the CO2 absorption rate, in g / h; P is the absolute pressure of the gas, in kPa; V in This refers to the inlet gas flow rate, in meters per second (m³). 3 / h;C in V represents the carbon dioxide concentration in the inlet gas, expressed as vol%. out This refers to the outlet gas flow rate, in meters per second (m³). 3 / h;C out 1 is the concentration of carbon dioxide in the outlet gas, in vol%; Z is the compressibility factor, dimensionless; R is the gas constant, 8.314 J / (mol·K); T is the temperature of the gas, in K; and 44 is the molar mass of carbon dioxide, in g / mol.

[0045] Specifically, this application selects the absolute pressure of the gas during a series of mineralization processes to obtain the partial pressure of CO2 in the gas. The absorption rate η of CO2 was obtained through experiments, and then the partial pressure of CO2 in the gas was established. The function relationship between the absorption rate η of CO2 and the highest power coefficient is selected as the α value.

[0046] In some specific implementations, β is obtained in the following way:

[0047] After the mineral raw materials are spread out, gas is introduced under sealed conditions to establish a gas flow rate u on the surface of the mineral raw materials. g The β value is obtained by relating the CO2 absorption rate η to the CO2 absorption rate η, where the CO2 absorption rate η is calculated according to formula (3).

[0048] Specifically, this application selects an air velocity u during a series of mineralization processes. g Thus, the absorption rate η of a series of CO2 is calculated, and then the air flow rate u is established. g The function relationship between η and CO2 absorption rate is used to select the highest power coefficient, which is the β value.

[0049] In some specific implementations, σ is obtained in the following way:

[0050] After the mineral raw materials are spread out, gas is introduced while the mineral raw materials are moved under sealed conditions to establish the moving speed u of the mineral raw materials. s The β value is obtained by relating the CO2 absorption rate η to the CO2 absorption rate η, where the CO2 absorption rate η is calculated according to formula (3).

[0051] Specifically, this application selects the movement velocity u of mineral raw materials during a series of mineralization processes. s Thus, the absorption rate η of a series of CO2 is calculated, and then the movement velocity u of the mineral raw materials is established. s The function relationship between the absorption rate η of CO2 and the highest power coefficient is selected as the σ value.

[0052] In some specific implementations, ψ is obtained in the following way:

[0053] After the mineral raw materials are spread out, gas is introduced under sealed conditions to establish a functional relationship between the particle size d of the mineral raw materials and the absorption rate η of CO2, and obtain the β value. The absorption rate η of CO2 is calculated according to formula (3).

[0054] Specifically, this application selects the particle size d of the mineral raw materials in a series of mineralization processes to calculate the absorption rate η of CO2 in a series of processes. Then, it establishes a functional relationship between the particle size d of the mineral raw materials and the absorption rate η of CO2, and selects its highest power coefficient, which is the ψ value.

[0055] Once the surface renewal frequency of the mineral raw materials is obtained, surface renewal of the mineral raw materials according to this frequency can increase the absorption rate of CO2 in the gas by the mineral raw materials and increase the utilization rate of the CO2-fixable components in the mineral raw materials.

[0056] This application establishes a method including the partial pressure of CO2 in a gas. and the absolute humidity R of the gas w Physical property parameters of gases and including the water content S of mineral raw materials w The content of CO2-fixable components in mineral raw materials (w) t The method describes the functional relationship between physical property parameters of mineralized raw materials, including bulk density ρ and particle size d. Based on these properties, the frequency of surface renewal of the mineralized raw materials is determined. Renewing the surface of the mineralized raw materials at this frequency increases the absorption rate of CO2 from the gas and improves the utilization rate of the CO2-fixable components in the mineralized raw materials. Experimental results show that when using the method provided in this application to mineralize CO2 in the air, the average absorption rate of CO2 in the air can reach 20 g / m³. 2 The utilization rate of mineralizable components (calculated as calcium hydroxide) in the mineralized raw materials is above 90% per hour. Attached Figure Description

[0057] Figure 1 is a flowchart illustrating the method provided in this application. Detailed Implementation

[0058] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0059] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0060] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0061] This application provides a method for mineralizing CO2 in a gas, comprising the following steps:

[0062] The CO2 in the gas is mineralized using mineralized raw materials, and the surface of the mineralized raw materials is renewed at a predetermined renewal frequency during the mineralization process.

[0063] The update frequency is determined according to the functional relationship between the physical property parameters of the mineralized raw material and the physical property parameters of the gas;

[0064] The physical property parameters of the mineralized raw material include the moisture content S. wThe content of CO2-fixable components in mineral raw materials (w) t At least one of the following: %, bulk density ρ of the mineralized raw material, and particle size d of the mineralized raw material;

[0065] The physical properties of the gas include the partial pressure of CO2 in the gas. and the absolute humidity R of the gas w At least one of them.

[0066] Referring to Figure 1, which is a flowchart of the method provided in this application, this application introduces CO2-containing gas, such as air, into the mineral raw material for mineralization. After the surface of the mineral raw material is renewed at a predetermined frequency, CO2-containing gas is continued to be introduced for mineralization until all the mineral raw material is carbonized. This method can increase the absorption rate of CO2 in the gas by the mineral raw material and increase the utilization rate of the CO2-fixable components in the mineral raw material.

[0067] The method for extracting CO2 from mineralized gases provided in this application will be described in detail below with reference to embodiments.

[0068] Example 1

[0069] This embodiment uses industrial solid waste carbide slag as the mineralization raw material. The carbide slag has a moisture content of 5%, a particle size of 100 mesh, and a bulk density ρ of 400 kg / m³. 3 The mass fraction of calcium hydroxide, which is a mineralizable CO2 component, is 85%.

[0070] Determination of α value:

[0071] Take 1 kg of the above-mentioned calcium carbide slag and spread it to a thickness δ of 0.002 m and a spreading area of ​​1.25 m². 2 After sealing, air was introduced into the chamber; the concentration of CO2 in the air at normal pressure was measured to be 380 ppm. The partial pressure of CO2 in the air was adjusted according to the data shown in Table 1. Simultaneously control the absolute humidity R of the air w The air velocity u at the surface of carbide slag is 8 g / kg dry air. g Given a flow rate of 3 m / s, measure the CO2 concentration and ventilation rate at the inlet and outlet, and calculate the CO2 absorption rate η using the following formula, in g / h:

[0072]

[0073] Where: P represents the absolute pressure of air, kPa; V in For the inlet air flow rate, m 3 / h;

[0074] C in V represents the carbon dioxide concentration of the imported feed gas, in vol%. outThe output flow rate of the raw gas is m. 3 / h;

[0075] C out 1 is the carbon dioxide concentration of the outlet feed gas, vol%; Z is the compressibility factor, dimensionless; R represents the gas constant, with a value of 8.314 J / (mol·K); T represents the gas temperature, K; 44 is the molar mass of carbon dioxide, g / mol.

[0076] The results are shown in Table 1, which presents the experimental results of the determination of the α value in Example 1.

[0077] Table 1. Experimental results of α value determination in Example 1

[0078] Regarding the experimental results η and The fitting yielded, If R² = 0.99525, then α takes the value 1.

[0079] Determination of β value:

[0080] The experimental procedure and method are the same as those for determining the α value, except that the air velocity u on the surface of the carbide slag is adjusted according to the parameters shown in Table 2. g Regarding the experimental results η and u g The fitting yielded, R 2 =0.9891, then β takes the value of 2.

[0081] Table 2. Experimental results of β value determination in Example 1

[0082] Determination of σ value:

[0083] The experimental method is the same as that for determining the α value, except that the carbide slag is tumbled and moved at a certain speed, and the moving speed u of the carbide slag is adjusted according to the parameters in Table 3. s Regarding the experimental results η and u s The fitting yielded,

[0084] R 2 =0.9908, then σ takes the value of 3.

[0085] Table 3. Experimental results of σ value determination in Example 1

[0086] Determination of ψ value:

[0087] The experimental procedure and method were the same as those for determining the α value, except that the particle size d of the carbide slag was adjusted according to the parameters in Table 4. Fitting the experimental results η and d yielded: η = -24840d + 45.649, R0 2 =0.9816, then ψ takes the value of 1.

[0088] Table 4. Experimental results of ψ value determination in Example 1

[0089] α, β, σ, and ψ satisfy Formula 2

[0090] 2α+β-σ=ψ (Formula 2)

[0091] Calculate the update frequency using Formula 1:

[0092]

[0093] In this embodiment, the moisture content S of the carbide slag w The content is 5%, and the particle size of the carbide slag is 100 mesh, that is, d is 1.5×10. -4 m; The measured bulk density ρ of the carbide slag was 400 kg / m³. 3 The mass fraction w of calcium hydroxide, a mineralizable CO2 component in carbide slag. t The percentage was 85%; under normal pressure, the concentration of CO2 in the air was 380 ppm, the partial pressure was 0.0385 kPa, and the absolute humidity R of the air during the experiment was... w 12 g / kg dry air, airflow velocity u g The relative velocity of the carbide slag is 2.5 m / s. s The velocity is 0.12 m / s. The calculated surface renewal frequency of carbide slag should be 34.4 h, that is, the surface of carbide slag should be renewed every 34.4 h.

[0094] Under the above conditions, 500 kg of carbide slag was placed on a conveyor belt with an area of ​​12.5 m². 2 The calcium carbide slag was spread to a thickness of 5 cm. A conveyor belt reciprocated, and air was blown in from above the belt. Every 34.4 hours, a 0.5 cm thick layer was scraped away using a flat scraper until completely removed. The change in carbonate content in the calcium carbide slag after the reaction was completed was measured, and the average air absorption rate was calculated to be 65.28 g / m³. 2 / h, the utilization rate of calcium hydroxide in carbide slag is 96.31%.

[0095] Example 2

[0096] The mineralization of CO2 in the air was carried out using the same method and steps as in Example 1, except that the mineralization raw material was steel slag with a calcium oxide content of 35.26% and a moisture content of S. w The content is 3%, the particle size is 200 mesh, that is, d is 0.75×10. -4 The bulk density ρ of the steel slag is 750 kg / m³. 3 The mass fraction w of calcium oxide, a component that can mineralize CO2.t The percentage is 35.26%, using air at normal pressure, the CO2 concentration is 380 ppm, the partial pressure is 0.0385 kPa, and the absolute humidity of the air is R. w 14 g / kg dry air, airflow velocity u g The relative velocity of the steel slag is 4.5 m / s, and the relative velocity of the steel slag is u. s With a velocity of 0.5 m / s, the correlation coefficients for the steel slag renewal frequency under the above conditions were measured to be α = 1, β = 3, σ = 2, and ψ = 3. Based on the surface renewal frequency formula, the calculated surface renewal frequency of the steel slag should be 2.46 h, meaning that the steel slag surface needs to be renewed every 2.46 h.

[0097] Under the above conditions, 500 kg of steel slag is placed on a conveyor belt with an area of ​​12.5 m². 2 The steel slag was laid in a 3cm thick layer. A conveyor belt reciprocated at a speed of 0.5m / s. Air was blown in above the conveyor belt at a velocity of 4.5m / s. The belt was vibrated every 2.46 hours to mix and replace the surface and bottom layers of steel slag. The change in carbonate content in the steel slag after the reaction was completed was measured, and the average air absorption rate was calculated to be 25.06 g / m³. 2 / h, the utilization rate of calcium (calculated as calcium hydroxide) in steel slag is 90.17%.

[0098] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

A method for mineralizing CO2 in a gas includes the following steps: The CO2 in the gas is mineralized using mineralized raw materials, and the surface of the mineralized raw materials is renewed at a predetermined renewal frequency during the mineralization process. The update frequency is determined according to the functional relationship between the physical property parameters of the mineralized raw material and the physical property parameters of the gas; The physical property parameters of the mineralized raw material include the moisture content S. w The content of CO2-fixable components in mineral raw materials (w) t At least one of the following: %, bulk density ρ of the mineralized raw material, and particle size d of the mineralized raw material; The physical properties of the gas include the partial pressure of CO2 in the gas. and the absolute humidity R of the gas w At least one of them. The method according to claim 1, characterized in that, During the mineralization process, gas is introduced while the mineralized raw materials are moving. The method according to claim 2, characterized in that, The physical property parameters of the mineralized raw material include the moisture content S. w The content of CO2-fixable components in mineral raw materials (w) t %, bulk density ρ of mineralized raw materials, particle size d of mineralized raw materials, and moving velocity u of mineralized raw materials. s ; The physical properties of the air include the partial pressure of CO2 in the gas. absolute humidity R of a gas w and gas flow rate u g . The method according to claim 3, characterized in that, The functional relationship between the physical property parameters of the mineral raw material and the physical property parameters of the gas satisfies formula (1): In formula (1), F is the surface renewal frequency of the mineral raw material, with the unit being 1 / h; This is the partial pressure of CO2 in a gas, expressed in kp. a ;R w The absolute humidity of a gas, expressed in g / kg dry gas; u g S represents gas flow velocity, measured in m / s. w Moisture content of mineralized raw materials, in %; w t % represents the content of CO2-fixable components in the mineralized raw material, expressed as a percentage; ρ represents the bulk density of the mineralized raw material, expressed as kg / m³. 3 ;u s d represents the moving velocity of the mineralized raw material, in m / s; d represents the particle size of the mineralized raw material, in m. α is the highest power coefficient of the power function of the effect of the partial pressure of CO2 in the gas on the CO2 absorption rate; β is the highest power coefficient of the power function of the effect of the gas flow rate on the CO2 absorption rate; σ is the highest power coefficient of the power function of the effect of the moving speed of the mineral raw material on the CO2 absorption rate; ψ is the highest power coefficient of the power function of the effect of the particle size of the mineral raw material on the CO2 absorption rate. The method according to claim 4, characterized in that, α, β, σ and ψ satisfy formula (2): Formula (2): 2α+β-σ=ψ The method according to claim 5, characterized in that, α is obtained as follows: After the mineral raw materials are spread out, gas is introduced under sealed conditions to establish the partial pressure of CO2 in the gas. The value of α is obtained by determining the functional relationship between α and the CO2 absorption rate η. The CO2 absorption rate η is calculated according to formula (3): In formula (3), η is the CO2 absorption rate, in g / h; P is the absolute pressure of the gas, in kPa; V in This refers to the inlet gas flow rate, in meters per second (m³). 3 / h;C in V represents the carbon dioxide concentration in the inlet gas, expressed as vol%. out This refers to the outlet gas flow rate, in meters per second (m³). 3 / h;C out Z is the carbon dioxide concentration of the outlet gas, in vol%; R is the compressibility factor; T is the gas constant; and T is the gas temperature, in K. β is obtained as follows: After the mineral raw materials are spread out, gas is introduced under sealed conditions to establish a gas flow rate u on the surface of the mineral raw materials. g The β value is obtained by relating the CO2 absorption rate η to the CO2 absorption rate η, where the CO2 absorption rate η is calculated according to formula (3). σ is obtained as follows: After the mineral raw materials are spread out, gas is introduced while the mineral raw materials are moved under sealed conditions to establish the moving speed u of the mineral raw materials. s The β value is obtained by relating the CO2 absorption rate η to the CO2 absorption rate η, where the CO2 absorption rate η is calculated according to formula (3). ψ is obtained as follows: After the mineral raw materials are spread out, gas is introduced under sealed conditions to establish a functional relationship between the particle size d of the mineral raw materials and the absorption rate η of CO2, and obtain the β value. The absorption rate η of CO2 is calculated according to formula (3). The method according to any one of claims 1 to 6, characterized in that, The mineral raw materials are selected from carbide slag, steel slag, red mud, serpentine, magnesium olivine, basalt, volcanic ash, concrete, or wollastonite. The method according to claim 7, characterized in that, The dry weight of the mineralized raw material is 10 kg / m³. 2 ~50kg / m 2 The mineralizable CO2 component in the mineralized raw material is not less than 5%; the moisture content of the mineralized raw material is 2wt% to 40wt%; and the particle size of the mineralized raw material is 20 mesh to 2000 mesh. The method according to claim 7, characterized in that, The gas is air or CO2-containing waste gas; The water content of the gas is 2 g / kg dry gas to 40 g / kg dry gas. The method according to any one of claims 1 to 6, characterized in that, The surface renewal method is at least one of tumbling, stirring, scraping, vibrating, blowing, rocking, sliding, and fluidizing.

Images