System and method for integrated utilization of molecular sieve raw powder and steel slag

Abstract

The present application relates to the technical field of carbon capture, and discloses a system and method for integrated utilization of molecular sieve raw powder and steel slag, comprising a temperature swing adsorption device, wherein the temperature swing adsorption device comprises an adsorption module, a heating regeneration module and a gas purging regeneration cooling module, the gas of the gas purging regeneration cooling module is cold air, the heating regeneration module and the gas purging regeneration cooling module respectively collect product gas through a first collector and a second collector, the first collector collects high-concentration product gas, and the second collector collects medium-concentration product gas; the low-concentration CO2 product gas collected in the cooling and purging synchronous process is used for carbonizing the mixture, the diffusion rate of CO2 in the steel slag is improved, and the carbonization reaction rate, capacity, strength and stability of the steel slag are improved, the process flow is simplified, and finally the carbonization time is shortened to 10-15 h, and the carbonization capacity is improved to 20%.

Description

Technical Field

[0001] This invention relates to the field of carbon capture technology, specifically a system and method for the integrated utilization of molecular sieve powder and steel slag. Background Technology

[0002] The development of CO2 capture and utilization technology in the steel industry has been slow, mainly due to the high cost and energy consumption of CO2 capture. The adsorbent is pulverized during replacement and movement, resulting in adsorbent loss and increasing the investment cost of CO2 capture. This limits the large-scale promotion and utilization of adsorption technology in the field of CO2 capture. At the same time, steel slag is an alkaline solid waste generated during the converter steelmaking process. Due to the poor pore structure of steel slag, the diffusion rate of CO2 in the slag channels is slow, resulting in long carbonization reaction time and small carbonization capacity. Summary of the Invention

[0003] The purpose of this invention is to provide a system and method for the integrated utilization of molecular sieve powder and steel slag, so as to solve the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution:

[0005] A system integrating molecular sieve powder and steel slag utilization includes a temperature-switching adsorption device, which comprises an adsorption module, a heating and regeneration module, and a gas purging and regeneration cooling module. The gas in the gas purging and regeneration cooling module is cold air. The heating and regeneration module and the gas purging and regeneration cooling module respectively collect product gas through a first collector and a second collector. The first collector collects high-concentration product gas, and the second collector collects medium-concentration product gas.

[0006] The pulverized molecular sieve generated by the temperature-switching adsorption device is collected by a collector and weighed by a weighing device. The proportioner adjusts other components based on the weight of the pulverized molecular sieve measured by the weighing device. The proportioner is 0.5-5 parts pulverized molecular sieve, 10-15 parts gel material, 70-80 parts steel slag, and 8-10 parts water. The mixture proportioned by the proportioner is pressed into shape by a mixing and pressing molding device and distributed to two carbonization devices for carbonization.

[0007] The medium-concentration product gas collected by the second collector is diverted to the two carbonization devices through the gas diversion mechanism, and the gas concentration inside the carbonization device is detected by the concentration detector B to keep the carbon dioxide concentration in the carbonization device at 50%.

[0008] As a further aspect of the present invention: a concentration detector A is provided inside the gas purging regeneration cooling module or at the air inlet end of the second collector. When the concentration of the product gas collected by the second collector is less than 30%, the collection stops.

[0009] As a further aspect of the present invention: when the gas concentration in the carbonization device collected by the concentration detector B is less than 20%, the gas diversion supply mechanism replenishes the gas; when the gas concentration in the carbonization device collected by the concentration detector B is greater than 50%, the gas diversion supply mechanism stops replenishing the gas.

[0010] As a further embodiment of the present invention: the molecular sieve of the temperature-switching adsorption device includes, but is not limited to, type 13X, type 10X, type Y, type ZSM-5, type 5A, or natural clinoptilolite, and the molecular sieve is a Ca ion modified material.

[0011] As a further aspect of the present invention, a method for using a system integrating molecular sieve powder and steel slag utilization includes:

[0012] S1: The industrial flue gas after ultra-low emission enters the temperature-switching adsorption device, which uses the medium-low temperature waste heat of 100-150℃ for desorption. The adsorption steps of the temperature-switching adsorption device are adsorption + heating regeneration + cold air purging regeneration and cooling. The adsorption time is 10-20 min, the heating regeneration time is 15-30 min, and the cold air purging regeneration time is 5-10 min. The CO2 product gas concentration obtained in the heating regeneration and purging stages differs greatly. It is collected by the first collector and the second collector respectively. The first collector collects 80%-90% of the high-concentration CO2 product gas, and the second collector collects 30%-50% of the medium-concentration CO2 product gas. When the CO2 concentration in the cold air purging regeneration is lower than 30%, the collection of medium-concentration CO2 product gas is stopped.

[0013] S2: Collect the pulverized molecular sieve that is worn during the heat dissipation process of the temperature-switching adsorption device. After the pulverized molecular sieve is weighed by the weighing device, the proportioner adjusts the mass of gel material, steel slag and water according to the proportion. The four components are quantitatively mixed and stirred evenly by the feeding pump and mixer of the mixing and pressing molding device, and then pressed and molded at a pressing pressure of 10-20MPa.

[0014] S3: Low-concentration product gas reacts with pressed steel slag for carbonization. Due to the high CO2 concentration in this method, and the addition of a large amount of activator and active components, the carbonization time is 5–10 hours, and the carbonization amount is 20%.

[0015] S4: The gas supply mechanism circulates CO2 into carbonization device A. When the concentration reaches 50%, the gas supply stops. After switching the valve, CO2 is introduced into carbonization device B. When the concentration reaches 50%, the gas supply stops. When the CO2 concentration in carbonization device A is lower than 20%, CO2 is introduced again to raise the CO2 concentration to 50%.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] The abundant pore structure and large specific surface area of ​​pulverized molecular sieves, when incorporated into steel slag, can effectively improve the diffusion rate of CO2 in the steel slag mixture. A proportioner obtains a mixture of pulverized molecular sieves, gel material, steel slag, and water according to a set ratio. Low-concentration CO2 product gas collected during the simultaneous cooling and purging process is used to carbonize the mixture, increasing the CO2 diffusion rate in the steel slag and thus improving the carbonization reaction rate, capacity, strength, and stability. Simultaneously, the process is simplified, ultimately shortening the carbonization time to 10–15 hours and increasing the carbonization amount to 20%. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart of a system that integrates the utilization of molecular sieve raw powder and steel slag;

[0020] In the diagram: 1. Temperature-switching adsorption device; 11. Collector; 12. Weighing device; 2. First collector; 3. Second collector; 4. Concentration detector A; 5. Diverting gas supply mechanism; 51. Concentration detector B; 6. Carbonization device; 7. Mixing and pressing molding device; 8. Proportioning device. Detailed Implementation

[0021] Example 1:

[0022] Please see Figure 1 This embodiment includes a temperature-switching adsorption device 1, which includes an adsorption module, a heating and regeneration module, and a gas purging, regeneration, and cooling module. The gas used in the gas purging, regeneration, and cooling module is cold air. The heating and regeneration module and the gas purging, regeneration, and cooling module collect product gas through a first collector 2 and a second collector 3, respectively. The first collector 2 collects high-concentration product gas, and the second collector 3 collects medium-concentration product gas.

[0023] In this embodiment, the desorption requirements can be met using residual heat at a medium-low temperature of 100℃ to 150℃. The temperature-switched adsorption process consists of adsorption + heating regeneration + cold air purging regeneration. The adsorption time is 10-20 min, the heating regeneration time is 15-30 min, and the cold air purging regeneration time is 5-10 min. The CO2 product gas concentrations obtained during the heating regeneration and purging stages differ significantly and are collected separately, designated as high-concentration CO2 product gas and medium-concentration CO2 product gas, respectively. Collection of medium-concentration CO2 product gas is stopped when the CO2 concentration falls below 30% during cold air purging regeneration. The advantage of this method is that the temperature-switched adsorption process generally consists of three basic steps: adsorption, desorption, and cooling. The desorption step often uses a combination of indirect heating and purging gas to improve desorption performance. The CO2 product gas concentration obtained by indirect heating is high, reaching 80-90%. The purge gas can be either high-temperature product gas or high-temperature N2. High-temperature product gas, when purged with product gas, results in a high concentration of desorbed CO2, but this reduces adsorbent productivity. High-temperature N2, when purged with inert gas, results in a lower concentration of desorbed CO2, but still meets the CO2 concentration requirements of this method. Furthermore, this method combines the inert gas purging step with the cooling step, using ambient temperature air to purge the adsorbent. This reduces the use of inert gas while still meeting the CO2 concentration requirements of this method, thus solving the energy issue. Simultaneously, the high-concentration CO2 product gas obtained by the first collector 2 and the second collector 3 can be used in other processes.

[0024] In this embodiment, the pulverized molecular sieve generated by the temperature-switching adsorption device 1 is collected by the collector 11 and weighed by the weighing device 12. The proportioner 8 adjusts other components according to the weight of the pulverized molecular sieve weighed by the weighing device 12. The proportion of the proportioner 8 is 0.5-5 parts pulverized molecular sieve, 10-15 parts gel material, 70-80 parts steel slag, and 8-10 parts water. The mixed material proportioned by the proportioner 8 is pressed into shape by the mixing and pressing molding device 7 and distributed to the two carbonization devices 6 for carbonization.

[0025] In this embodiment, the molecular sieve exhibits good compatibility with steel slag. The main components of the molecular sieve are the same as those of the steel slag, namely SiO2 (40-45%), Al2O3 (30-40%), and CaO / MgO / NaO (15-20%). The pulverized molecular sieve has a small particle size and a specific surface area of ​​700-800 m² / g, exhibiting high activity and eliminating the need for manual grinding. Molecular sieves include types 13X, 10X, Y, ZSM-5, 5A, and natural clinoptilolite. Optimized, these molecular sieves are Ca-ion modified materials. The Ca-modified molecular sieve, when mixed with steel slag, forms a dopant material that serves as the excitation material. Ca, as a basic ion, provides an alkaline environment, promoting the breaking of Si-O and Al-O bonds in steel slag. CaO trapped in the steel slag by SiO2 and Al2O3 can dissociate and increase the reaction rate with CO2. The silica component in the steel slag can also react with magnesium, iron, and other elements in the steel slag to form olivine, which has high strength, further improving its strength and volume stability. Finally, the large specific surface area and rich porosity of molecular sieves contribute to the diffusion rate of CO2 in steel slag.

[0026] In this embodiment, the material ratio is: steel slag (70-80 parts) + activating material (0.5-5 parts) + gel-activating material (10-20 parts) + water (8-10 parts). The activating material provides an alkaline environment to promote the breaking of the glassy structure of the steel slag (silicon-oxygen and aluminum-oxygen bonds), which facilitates the release of calcium ions and increases the contact area between calcium ions and CO2. The gel-activating material's role is that the gel component (calcium silicate) in the steel slag has poor activity and a slow reaction rate; adding some highly active gel-activating components helps to accelerate the reaction rate. Water promotes material mixing, CO2 dissolution, and Ca ion precipitation.

[0027] In this embodiment, the medium-concentration product gas collected by the second collector 3 is diverted to the two carbonization devices 6 through the gas diversion and supply mechanism 5, and the gas concentration inside the carbonization device 6 is detected by the concentration detector B51 to keep the carbon dioxide concentration inside the carbonization device 6 at 50%. A concentration detector A4 is installed inside the gas purging regeneration cooling module or at the gas inlet end of the second collector 3. When the concentration of the product gas collected by the second collector 3 is less than 30%, the collection stops.

[0028] In this embodiment, to minimize the system's energy consumption, waste heat from steel plant flue gas is used for temperature-variable CO2 adsorption. While maintaining consistent carbonization performance, the purity of the CO2 product gas is reduced as much as possible to save energy. The minimum CO2 concentration for carbonization is 10%, but a 72-hour carbonization reaction time is required. Medium-concentration product gas (30-50% CO2) reacts with pressed steel slag for carbonization. A large amount of activator and active components are added, thus shortening the carbonization time from the original 48-72 hours to 5-10 hours, and increasing the carbonization amount from 10% to a maximum of 20%.

[0029] In this embodiment, when the gas concentration in the carbonization device 6 detected by the concentration detector B51 is less than 20%, the gas supply mechanism 5 replenishes the gas. When the gas concentration in the carbonization device 6 detected by the concentration detector B51 is greater than 50%, the gas supply mechanism 5 stops replenishing the gas. Since the adsorption process product gas generation is continuous and the carbonization process is intermittent, multiple carbonization devices 6 are set at the downstream end to ensure the matching of the two processes. For example, when the CO2 concentration in carbonization device A reaches 50%, the gas supply is stopped, and the valve is switched to introduce CO2 into carbonization device B. When the CO2 concentration in carbonization device A is lower than 20%, CO2 is introduced again to bring the CO2 concentration back to 50%.

[0030] In this embodiment, the molecular sieve of the temperature-switching adsorption device 1 includes, but is not limited to, type 13X, type 10X, type Y, type ZSM-5, type 5A, or natural clinoptilolite. The molecular sieve is a Ca-modified material, and the Ca-modified molecular sieve, when mixed with steel slag, forms a dopant material that serves as the excitation material. Ca, as a basic ion, provides an alkaline environment, promoting the breaking of Si-O and Al-O bonds in the steel slag. CaO encapsulated by SiO2 and Al2O3 in the steel slag can dissociate, increasing the reaction rate with CO2. Furthermore, the silica component of the steel slag can react with magnesium, iron, and other elements in the steel slag to generate olivine, which has high inherent strength, further improving its strength and volume stability. Finally, the large specific surface area and abundant pores of the molecular sieve contribute to the diffusion rate of CO2 in the steel slag.

[0031] Operating steps:

[0032] S1: The industrial flue gas after ultra-low emission enters the temperature-switching adsorption device 1, which desorbs the gas using the medium-low temperature waste heat at 100-150℃. The adsorption steps of the temperature-switching adsorption device 1 are adsorption + heating regeneration + cold air purging regeneration and cooling. The adsorption time is 10-20 min, the heating regeneration time is 15-30 min, and the cold air purging regeneration time is 5-10 min. The CO2 product gas concentration obtained in the heating regeneration and purging stages differs greatly. It is collected by the first collector 2 and the second collector 3 respectively. The first collector 2 collects 80%-90% high-concentration CO2 product gas, and the second collector 3 collects 30%-50% medium-concentration CO2 product gas. When the CO2 concentration in the cold air purging regeneration is lower than 30%, the collection of medium-concentration CO2 product gas is stopped.

[0033] S2: Collect the pulverized molecular sieve that is worn during the heat dissipation process of the temperature-switching adsorption device 1. After the weighing device 12 weighs the pulverized molecular sieve, the proportioner 8 adjusts the mass of the gel material, steel slag and water according to the proportion. The four components are quantitatively mixed and stirred evenly through the feeding pump and mixer of the mixing and pressing molding device 7, and then pressed and molded at a pressure of 10-20 MPa.

[0034] S3: Low-concentration product gas reacts with pressed steel slag for carbonization. Due to the high CO2 concentration in this method, and the addition of a large amount of activator and active components, the carbonization time is 5–10 hours, and the carbonization amount is 20%.

[0035] S4: The gas supply mechanism 5 introduces CO2 into carbonization device A. When the concentration reaches 50%, the gas supply is stopped. After switching the valve, CO2 is introduced into carbonization device B. When the concentration reaches 50%, the gas supply is stopped. When the CO2 concentration in carbonization device A is lower than 20%, CO2 is introduced again to raise the CO2 concentration to 50%.

[0036] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

[0037] Example 2: Basic data;

[0038] Compared with Example 2, Comparative Example 1 added 0.5 parts of pulverized molecular sieve, and other conditions remained unchanged, the carbonization time was shortened from 1 day to 20 hours;

[0039] Compared with Comparative Example 1, Comparative Example 2 replaced ZSM-5 molecular sieve with 13X molecular sieve. With other conditions unchanged, the carbonization time was shortened from 20h to 18h, and the carbonization amount increased by 13% from 12%. This is because the 13X molecular sieve has richer pores, which accelerates the CO2 mass transfer rate. The 13X molecular sieve contains more Ca ions, so the carbon fixation amount is higher.

[0040] Compared with Example 2, Comparative Example 3 increased the CO2 concentration from 20% to 30%, while keeping other conditions unchanged. The carbonization time intensity and carbonization amount increased from 80 MPa and 12% to 90 MPa and 14%, respectively.

[0041] Compared with Example 3, in Example 4, the amount of pulverized molecular sieve was increased from 0.5 parts to 5 parts, while other conditions remained unchanged. The carbonization time, intensity and amount of carbonization were increased from 80 MPa and 12% to 100 MPa and 17%, respectively, and the carbonization time was shortened to 15 h.

[0042] Compared with Example 4, Example 5 increased the CO2 concentration from 30% to 40%, while keeping other conditions unchanged. The carbonization time, intensity, and amount of carbonization increased from 100 MPa and 17% to 100 MPa and 20%, respectively, and the carbonization time was shortened to 10 hours.

[0043] Compared with Example 5, Example 6 increased the CO2 concentration from 40% to 50%, while keeping other conditions unchanged. The carbonation amount decreased from 20 to 100 MPa and 18% (a dense calcium carbonate film would form on the surface of the steel slag, which would hinder further carbonation reaction).

[0044]

[0045]

Claims

1. A system integrating pulverized molecular sieve and steel slag utilization, comprising a temperature-switching adsorption device (1), characterized in that: The temperature-changing adsorption device (1) includes an adsorption module, a heating and regeneration module, and a gas purging, regeneration, and cooling module. The gas in the gas purging, regeneration, and cooling module is cold air. The heating and regeneration module and the gas purging, regeneration, and cooling module collect product gas through a first collector (2) and a second collector (3), respectively. The first collector (2) collects product gas with a concentration of 80%-90%, and the second collector (3) collects product gas with a concentration of 30%-50%. The pulverized molecular sieve generated by the temperature-changing adsorption device (1) is collected by the collector (11) and weighed by the weighing device (12). The proportioner (8) adjusts other components according to the weight of the pulverized molecular sieve weighed by the weighing device (12). The proportion of the proportioner (8) is 0.5-5 parts pulverized molecular sieve, 10 parts cementing material, 70-75 parts steel slag, and 15 parts water. The cementing material includes one or more of desulfurized gypsum, desulfurized ash, carbide slag, cement, and CaOH2. The mixed material proportioned by the proportioner (8) is pressed into shape by the mixing and pressing molding device (7) and distributed to two carbonization devices (6) for carbonization. The medium-concentration product gas collected by the second collector (3) is diverted to the two carbonization devices (6) through the gas diversion mechanism (5), and the gas concentration inside the carbonization device (6) is detected by the concentration detector B (51) to keep the carbon dioxide concentration inside the carbonization device (6) at 50%. A concentration detector A (4) is installed inside the gas purging regeneration cooling module or at the air inlet of the second collector (3). When the concentration of the product gas collected by the second collector (3) is less than 30%, the collection stops.

2. The integrated system for pulverized molecular sieve and steel slag utilization according to claim 1, characterized in that: When the gas concentration in the carbonization device (6) collected by the concentration detector B (51) is less than 20%, the gas diversion supply mechanism (5) replenishes the gas. When the gas concentration in the carbonization device (6) collected by the concentration detector B (51) is greater than 50%, the gas diversion supply mechanism (5) stops replenishing the gas.

3. The integrated system for pulverized molecular sieve and steel slag utilization according to claim 1, characterized in that: The molecular sieve of the variable temperature adsorption device (1) is modified with Ca ions, and the molecular sieve types include 13X type, 10X type, Y type, ZSM-5 type, 5A type, or natural clinoptilolite type.

4. The method of using the integrated system of pulverized molecular sieve and steel slag utilization according to any one of claims 1-3, characterized in that: include: S1: The industrial flue gas after ultra-low emission enters the temperature-switching adsorption device (1) and is desorbed by the medium-low temperature waste heat of 100~150℃. The adsorption steps of the temperature-switching adsorption device (1) are adsorption + heating regeneration + cold air purging regeneration and cooling. The adsorption time is 10-20 min, the heating regeneration time is 15-30 min, and the cold air purging regeneration time is 5-10 min. The CO2 product gas concentration obtained in the heating regeneration and purging stages is large. It is collected by the first collector (2) and the second collector (3) respectively. The first collector (2) collects CO2 product gas with a concentration of 80%-90%, and the second collector (3) collects CO2 product gas with a concentration of 30%-50%. When the CO2 concentration in the cold air purging regeneration is lower than 30%, the collection of medium-concentration CO2 product gas is stopped. S2: Collect the pulverized molecular sieve that is worn during the heat dissipation process of the temperature-changing adsorption device (1). After the weighing device (12) weighs the pulverized molecular sieve, the proportioner (8) adjusts the mass of the cementitious material, steel slag and water according to the proportion. The four components are quantitatively mixed and stirred evenly through the feeding pump and mixer of the mixing and pressing molding device (7), and then pressed and molded. The pressing pressure is 10-20MPa. S3: Medium-concentration product gas undergoes a carbonization reaction with pressed steel slag, and a large amount of activator and active components are added. The carbonization time is 5-10 hours, and the carbonization amount is 20%. S4: The gas supply mechanism (5) introduces CO2 into carbonization device A. When the concentration reaches 50%, the gas supply is stopped. After switching the valve, CO2 is introduced into carbonization device B. When the concentration reaches 50%, the gas supply is stopped. When the CO2 concentration in carbonization device A is lower than 20%, CO2 is introduced again to raise the CO2 concentration to 50%.

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