A concrete building material production system based on multi-point microcrystalline mineralization of composite carbon dioxide

Abstract

This invention discloses a concrete building material production system based on multi-point microcrystalline mineralization of composite carbon dioxide, belonging to the field of carbon dioxide mineralization and concrete preparation. The system includes a composite carbon dioxide generation module, a raw material processing module, a concrete production module, and an external carbon source. The composite carbon dioxide generation module includes a short-range phase separation device, a long-range gaseous buffer device, and a pressure dissolution device. The carbon source from the external carbon source is processed by the composite carbon dioxide generation module and then outputs carbon dioxide in the required state to the raw material processing module or the concrete production module. Precast building materials or slurries are prepared through the raw material processing module and the concrete production module, and these precast building materials or slurries are further used to prepare finished concrete building materials. This invention enables the preparation of carbon dioxide in multiple states to adapt to different concrete building material production processes, thereby improving the production efficiency and carbon dioxide absorption and conversion rate of concrete building materials.

Description

Technical Field

[0001] This invention relates to the fields of carbon dioxide mineralization and concrete preparation, and specifically to a concrete building material production system based on multi-point microcrystalline mineralization of composite carbon dioxide. Background Technology

[0002] In recent years, greenhouse gas emissions, primarily carbon dioxide, have been enormous. Reducing carbon emissions and realizing the resource conversion and utilization of CO2 are crucial measures to promote sustainable development. However, the building materials industry, with silicate cement as its core raw material, faces significant pressure to reduce emissions and struggles with decarbonization. CO2 mineralization and resource utilization technology has opened up a large-scale low-carbon path for the building materials industry. Because this reaction is spontaneous at room temperature, fast, and has a significant exothermic effect, CO2-mineralized building materials offer advantages over traditional building materials production / curing processes, including milder reaction conditions, higher production efficiency, and lower energy consumption. Furthermore, the alkaline components in the building materials system (such as calcium silicate clinker, hydrated calcium silicate gel, and calcium hydroxide) transform into carbonate crystals and calcium-modified silica gel during CO2 mineralization, thereby enhancing material performance and promoting rapid strength formation. Due to the diversity of building materials, different materials (including raw aggregates, cementitious materials, precast components, and ready-mixed concrete) place high demands on the reaction form, gas source state, and reactor type of CO2 mineralization.

[0003] Most existing concrete building material production methods mainly rely on conventional concrete mixing and autoclaving of precast components. Ready-mixed concrete batching plants have relatively mature technology, with their main carbon emissions concentrated in the production of raw material cement. Each kg of cement has an equivalent carbon emission of 0.6–1 kg, thus the high cement content keeps the total carbon emissions of commercial ready-mixed concrete products high throughout their entire lifecycle. For the autoclaving of precast building materials, existing products have a high content of industrial solid waste, thus requiring high-quality steam, generally requiring a pressure >1 MPa and a temperature >180℃, which also affects the carbon emissions throughout the product's lifecycle.

[0004] Chinese patent document CN108327072A discloses a building material production system based on carbon dioxide cascade mineralization. This system utilizes a cascade mineralization intensification device to achieve high production efficiency and CO2 conversion rate for CO2-mineralized curing of precast blocks, while simultaneously reducing energy consumption. However, this technology requires high CO2 gas partial pressure and involves significant investment in the intensification reactor, limiting the product to precast concrete building materials.

[0005] Chinese patent document CN115536432A discloses a method for carbon dioxide mineralization curing of precast concrete components. This method utilizes carbonated water and bicarbonate to penetrate the concrete surface within the mold, followed by CO2 mineralization in a sealed space, enabling rapid demolding and early strength formation. However, this technology has limited CO2 mineralization efficiency and poor process operability, and is only applicable to precast concrete building materials.

[0006] Chinese patent document CN109368642A discloses a method for improving the carbon dioxide absorption efficiency of fresh concrete. This method involves introducing CO2 gas into the fresh concrete and then stirring and grinding it, thereby promoting the absorption of CO2 by the cement paste system to form carbonate microcrystals and enhancing the CO2 absorption rate. However, for fresh concrete, the high mass transfer resistance at the gas-liquid interface between CO2 gas and the fresh concrete can cause uneven surface and internal reactions and low overall CO2 utilization.

[0007] Therefore, there is a need for a production system that can achieve the generation and mineralization enhancement of composite CO2, is applicable to different concrete building materials, has a high conversion rate, and is highly operable. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a concrete building material production system based on multi-point microcrystalline mineralization of composite carbon dioxide, which can realize the preparation of carbon dioxide in multiple states to adapt to different concrete building material production processes, thereby improving the production efficiency and carbon dioxide absorption and conversion rate of concrete building materials.

[0009] The specific technical solution adopted is as follows:

[0010] A concrete building material production system based on multi-point microcrystalline mineralization of composite carbon dioxide includes a composite carbon dioxide generation module, a raw material processing module, a concrete production module, and an external carbon source.

[0011] The composite carbon dioxide generation module includes a short-range phase separation device, a long-range gaseous buffer device, and a pressure dissolution device; wherein, the short-range phase separation device is used to convert liquid carbon dioxide into wet aerosol carbon dioxide, the long-range gaseous buffer device is used to convert liquid carbon dioxide or dry aerosol carbon dioxide into gaseous carbon dioxide at stable pressure, and the pressure dissolution device is used to convert gaseous carbon dioxide into dissolved carbon dioxide.

[0012] The carbon source from the external carbon source is processed by the composite carbon dioxide generation module and then outputs carbon dioxide in the state required by the raw material processing module or the concrete production module. Precast building materials or slurry are prepared by the raw material processing module and the concrete production module, and the precast building materials or slurry are further used to prepare finished concrete building materials.

[0013] Preferably, the concrete building material production system based on multi-point microcrystalline mineralization of composite carbon dioxide further includes a mobile strengthening module. The carbon source from the external carbon source is processed by the composite carbon dioxide generation module and then outputs carbon dioxide in the state required by the corresponding module to the raw material processing module, concrete production module or mobile strengthening module. The mobile strengthening module further processes the slurry prepared by the concrete production module into finished concrete building materials.

[0014] This invention, through the design of a composite carbon dioxide generation module, can provide multiple carbon sources, including gaseous, liquid, aerosol, dissolved, and humidity-controlled composite carbon dioxide. It flexibly adapts to the efficient multi-point microcrystalline mineralization of carbon dioxide in different types and states of concrete building material raw materials and products, effectively covering various building material production processes of multi-point microcrystalline mineralization of carbon dioxide, and improving the production efficiency of concrete building materials.

[0015] The short-range phase separation device includes a shut-off valve, a humidification chamber, and a steam / humidity generator. Liquid carbon dioxide, after being depressurized by the shut-off valve, forms dry aerosol carbon dioxide, which is then fed into the long-range gas buffer device through a pipeline, or fed into the humidification chamber for phase separation before being output as stable humid aerosol carbon dioxide. The steam / humidity generator is connected to the humidification chamber to ensure that the interior of the humidification chamber is saturated with water vapor and that the temperature is maintained at room temperature.

[0016] Preferably, to ensure the safety of the humidification chamber, a safety valve is installed inside the humidification chamber to prevent pressure buildup.

[0017] Preferably, the shut-off valve is a controllable opening valve, and a flow meter is installed at the front end of the shut-off valve to measure the liquid carbon dioxide.

[0018] Preferably, the connecting pipes in the short-range phase separation device are made of stainless steel flexible hoses, and the stainless steel flexible hoses are wrapped with heat insulation material to ensure the stability of carbon dioxide properties.

[0019] The long-range gaseous buffer device includes a long-range heat exchange tube, a pressure reducing valve group, and a gaseous buffer tank connected in sequence. Dry aerosol carbon dioxide from the shut-off valve or liquid carbon dioxide from an external carbon source undergoes heat exchange through the long-range heat exchange tube and pressure reduction through the pressure reducing valve group before entering the gaseous buffer tank for pressure stabilization, outputting gaseous carbon dioxide at a stable pressure.

[0020] Preferably, the long-distance heat exchange tube is made of stainless steel with good thermal conductivity. An array of heat dissipation fins is arranged along the length of the outer tube wall to enhance the heat exchange between the liquid carbon dioxide working fluid and the air inside the tube. A variable power auxiliary heating device is set at the tail end of the long-distance heat exchange tube to ensure heat exchange efficiency.

[0021] Preferably, the inlet design pressure of the pressure reducing valve assembly is 5MPa, and the outlet pressure is adjustable from 0 to 5MPa.

[0022] Preferably, the gaseous buffer tank is designed with a pressure of not less than 2.5 MPa, and a safety valve is installed to ensure pressure safety.

[0023] The pressure dissolving device includes a gas storage tank, a dissolving and stirring tank, and a pressure stabilizing valve. Gaseous carbon dioxide from a gaseous buffer tank or an external carbon source is pressurized by the gas storage tank and then input into the dissolving and stirring tank containing solvent. Pressure is applied and the tank is stirred to output dissolved carbon dioxide. The pressure stabilizing valve ensures that the internal pressure of the dissolving and stirring tank is stable. The pressure stabilizing valve is connected to the gaseous buffer tank through a drying device and a booster fan to recover the exhaust gas generated by the dissolving and stirring tank.

[0024] The solvents mentioned include, but are not limited to, water, saturated calcium hydroxide solution, sodium hydroxide solution, etc.

[0025] Preferably, the dissolving and stirring tank is made of stainless steel with a PTFE lining, designed with a pressure of not less than 1 MPa, and equipped with a magnetically coupled stirring element.

[0026] Preferably, the outlet of the dissolving and stirring tank is equipped with a shut-off valve with controllable opening to control the flow rate of dissolved carbon dioxide output.

[0027] The raw material processing module is connected to the long-range gaseous buffer device through a pipeline. The raw material processing module receives gaseous carbon dioxide at a stable pressure output from the long-range gaseous buffer device and performs pretreatment operations such as crushing, stirring and strengthening on the building material raw materials.

[0028] Preferably, the strengthening method is mechanical activation wet multi-point microcrystalline mineralization strengthening. Wet mechanical activation refers to controlling the humidity of the building material raw materials, inputting a carbon source for mechanical activation, resulting in mass transfer strengthening and multi-point microcrystalline mineralization reaction, thus enhancing the reaction process and mineralization efficiency; the exhaust gas generated after multi-point microcrystalline mineralization of the building material raw materials is recovered and reused.

[0029] The building material raw materials mentioned include, but are not limited to: silicate cement, alkaline-neutral industrial solid waste (such as fly ash, blast furnace slag, carbide slag, steel slag, etc.), building material aggregates (such as artificial lightweight aggregates, recycled aggregates from waste concrete, etc.), and carbonated active cementitious materials.

[0030] The concrete production module is connected to the short-range phase separation device, the long-range gaseous buffer device, and the pressure dissolving device via pipelines. The concrete production module receives wet aerosol carbon dioxide output from the short-range phase separation device, or receives gaseous carbon dioxide at stable pressure output from the long-range gaseous buffer device, or receives dissolved carbon dioxide output from the pressure dissolving device. It uses the wet aerosol carbon dioxide, the gaseous carbon dioxide at stable pressure, or the dissolved carbon dioxide and the building material raw materials transported by the raw material processing module to carry out a multi-point microcrystalline mineralization reaction to prepare precast building materials or slurry.

[0031] The concrete production module can produce precast building materials or slurries, including but not limited to commercial ready-mixed concrete, building slurry, neat cement paste, mortar, etc.

[0032] The mobile strengthening module is connected to the short-range phase separation device and the pressure dissolving device through pipelines. The mobile strengthening module receives wet aerosol carbon dioxide output from the short-range phase separation device or dissolved carbon dioxide output from the pressure dissolving device, so that the slurry undergoes a multi-point microcrystalline mineralization reaction with the wet aerosol carbon dioxide or dissolved carbon dioxide to prepare the finished concrete building material.

[0033] Preferably, the mobile reinforcement module is a concrete mixer truck that can be injected with composite carbon dioxide.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] (1) The composite carbon dioxide generation module in the system of the present invention can provide multiple carbon sources, including gaseous, liquid, aerosol, dissolved and humidity-controlled composite carbon dioxide, which can flexibly adapt to the efficient carbon dioxide multi-point microcrystalline mineralization of concrete building material raw materials and products of different types and states, effectively cover various building material production processes of carbon dioxide multi-point microcrystalline mineralization, and improve the production efficiency of concrete building materials.

[0036] (2) The raw material processing module in the system of the present invention can realize the crushing, stirring, mass transfer enhancement and multi-point microcrystalline mineralization reaction of granular and powdered building material raw materials. Through a specific waste gas recovery and reuse design, it enhances the mass transfer and reaction absorption efficiency of carbon dioxide in building material raw materials, while improving the utilization rate of carbon dioxide raw materials and further improving the processing efficiency.

[0037] (3) In this invention, the concrete production module combined with the mobile strengthening module can realize multi-point microcrystalline mineralization of premixed slurry materials from production to transportation, so as to flexibly cope with different concrete production and transportation processes and realize efficient carbon reduction throughout the entire life cycle of concrete products. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the concrete building material production system based on multi-point microcrystalline mineralization of composite carbon dioxide in this invention;

[0039] Figure 2 This is a schematic diagram of a composite carbon dioxide generation module;

[0040] Figure 3 This is a schematic diagram of a short-range phase separation device;

[0041] Figure 4 This is a schematic diagram of a long-range gaseous buffer device;

[0042] Figure 5 This is a schematic diagram of a pressure dissolving device;

[0043] The system includes: 1. Composite carbon dioxide generation module; 11. Short-range phase separation device; 111. Shut-off valve; 112. Humidification chamber; 113. Steam / humidity generator; 12. Long-range gaseous buffer device; 121. Long-range heat exchange tube; 122. Pressure reducing valve group; 123. Gaseous buffer tank; 13. Pressure dissolving device; 131. Gas storage tank; 132. Dissolving and stirring tank; 133. Pressure stabilizing valve; 2. Raw material processing module; 3. Concrete production module; 4. Moving reinforcement module; 5. External carbon source. Detailed Implementation

[0044] The present invention will be further illustrated below with reference to the embodiments and accompanying drawings. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Operating methods not specifically specified in the following embodiments are generally performed under conventional conditions or as recommended by the manufacturer.

[0045] like Figure 1 As shown, the concrete building material production system based on multi-point microcrystalline mineralization of composite carbon dioxide includes a composite carbon dioxide generation module 1, a raw material processing module 2, a concrete production module 3, a mobile strengthening module 4, and an external carbon source 5. The composite carbon dioxide generation module 1 includes a short-range phase separation device 11, a long-range gaseous buffer device 12, and a pressure dissolving device 13. The short-range phase separation device 11 is used to convert liquid carbon dioxide into wet aerosol carbon dioxide, the long-range gaseous buffer device 12 is used to convert liquid carbon dioxide or dry aerosol carbon dioxide into gaseous carbon dioxide under stable pressure, and the pressure dissolving device 13 is used to convert gaseous carbon dioxide into dissolved carbon dioxide.

[0046] The carbon source from external carbon source 5 is processed by composite carbon dioxide generation module 1 and then outputs carbon dioxide in the state required by the corresponding module to raw material processing module 2, concrete production module 3 or mobile strengthening module 4; precast building materials or slurry are prepared by raw material processing module 2 and concrete production module 3, and the precast building materials or slurry are further used to prepare finished concrete building materials; or, the slurry prepared by concrete production module 3 is further made into finished concrete building materials by mobile strengthening module 4.

[0047] like Figure 2 As shown, the short-range phase separation device 11 includes a shut-off valve 111, a humidification chamber 112, and a steam / humidity generator 113. The dry aerosol carbon dioxide formed after the liquid carbon dioxide is depressurized by the shut-off valve 111 is input into the long-range gas buffer device 12 through a pipeline, or it is directly input into the humidification chamber 112 for phase separation, and then output as stable humid aerosol carbon dioxide through a gas delivery pipeline. The steam / humidity generator 113 is connected to the humidification chamber 112 to ensure that the interior of the humidification chamber is saturated with water vapor and the temperature is maintained at room temperature.

[0048] The long-range gaseous buffer device 12 includes a long-range heat exchange tube 121, a pressure reducing valve group 122, and a gaseous buffer tank 123 connected in sequence. Dry aerosol carbon dioxide from the shut-off valve 111 or liquid carbon dioxide from the external carbon source 5 undergoes heat exchange through the long-range heat exchange tube 121 and pressure reduction through the pressure reducing valve group 122 before entering the gaseous buffer tank 123 for pressure stabilization, outputting gaseous carbon dioxide at a stable pressure; or gaseous carbon dioxide from the external carbon source 5 enters the gaseous buffer tank 123 after passing through the long-range heat exchange tube 121 and the pressure reducing valve group 122, for pressure stabilization, outputting gaseous carbon dioxide at a stable pressure.

[0049] The pressure dissolving device 13 includes a gas storage tank 131, a dissolving and stirring tank 132, and a pressure regulating valve 133. Gaseous carbon dioxide from a gaseous buffer tank 123 or an external carbon source 5 is injected into the dissolving and stirring tank 132 containing solvent, applying pressure and stirring, and dissolving carbon dioxide is output from the outlet. The pressure regulating valve 133 ensures stable internal pressure in the dissolving and stirring tank 132, and is connected to the gaseous buffer tank 123 via a drying device and a booster fan to recover the waste gas generated in the dissolving and stirring tank.

[0050] Example 1

[0051] In this embodiment, the external carbon source 5 is liquid carbon dioxide (tank truck, storage tank) at 2.74 MPa and -40°C. After the pressure is adjusted to <0.7 MPa by the shut-off valve 111 in the short-range phase separation device 11, the liquid carbon dioxide is rapidly depressurized to form dry ice. Part of the dry ice will sublimate during the transportation process to form gaseous carbon dioxide. The outlet of the shut-off valve 111 is dry aerosol carbon dioxide. Specifically, the shut-off valve 111 is a controllable opening valve, and a flow meter is installed at the front end of the shut-off valve to measure the liquid carbon dioxide.

[0052] like Figure 3 As shown, after the dry aerosol carbon dioxide enters the humidification chamber 112, it is further depressurized to <0.1MPa. At this time, saturated water vapor at <0.01MPa or saturated humid air at 99%RH (temperature below 40℃) is pumped into the humidification chamber 112. The shuttle time of carbon dioxide in the humidification chamber 112 should be less than 5 seconds. At this time, the water vapor or humid air condenses into droplets after exchanging heat with the low temperature dry aerosol carbon dioxide and forms a gas-solid-liquid three-phase fluid (wet aerosol carbon dioxide) for output.

[0053] It should be noted that the temperature inside the humidification chamber 112 needs to be controlled within the range of 0 to 4°C to prevent the water from freezing due to excessively low temperature. At the same time, the humidification chamber 112 is equipped with a drainage channel to recover the condensate to the steam / humidity generator 114. To ensure the safety of the humidification chamber, a safety valve is installed inside the humidification chamber 112 to prevent pressure accumulation.

[0054] The connecting pipes in the short-range phase separation device 11 use stainless steel flexible hoses, and the stainless steel flexible hoses are wrapped with polyurethane insulation material with a thermal coefficient of less than 0.15 to prevent the solid carbon dioxide particles in the humid aerosol carbon dioxide from undergoing heat exchange and sublimation.

[0055] It should be noted that the short-range phase separation device 11 needs to be purged and dried before and after each use to prevent residual moisture and dry ice in the device from clogging the pipes and valves during subsequent use.

[0056] The wet aerosol carbon dioxide output in this embodiment can supply reactive wet aerosol carbon dioxide to the concrete production module 3 and the mobile strengthening module 4, ensuring that the carbon dioxide mineralization reaction is sufficient.

[0057] This embodiment uses concrete production module 3 as an example to illustrate the impact of this system on the slurry production process and concrete performance:

[0058] (1) Coarse aggregate, fine aggregate, cement, auxiliary cementitious materials, and carbonation additives are mixed thoroughly in a mass ratio of 880 parts: 880 parts: 200 parts: 160 parts: 8 parts, and then 185 parts of water are added. The mixture is stirred in the raw material processing module 2 to obtain uniform fresh concrete.

[0059] (2) The uniform fresh concrete is transported to the multi-point microcrystalline mineralization reactor in the concrete production module 3. The wet aerosol carbon dioxide obtained in the above steps is introduced from the top of the reactor. The discharge flow rate is adjusted and controlled to 1.3 kg-CO2 / min. After stirring continuously at 30 rpm for 90 seconds, the reaction is completed and a paste-like slurry with a slump of 121 mm is obtained. Its initial setting time is 320 min and its final setting time is 370 min.

[0060] (3) The paste-like slurry was injected into a 10mm×10mm×10mm cube mold and sealed. After curing under natural conditions for 3 days, 7 days and 28 days respectively, the uniaxial compressive strength of the concrete building materials was 18.3MPa, 22.9MPa and 36.2MPa respectively, which met the strength requirements of C30 national standard concrete.

[0061] (4) The uniform fresh concrete is also transported to the multi-point microcrystalline mineralization reactor in the concrete production module 3. No carbon dioxide is introduced. After stirring continuously at 30 rpm for 90 seconds, the reaction is completed and a paste-like slurry with a slump of 148 mm is obtained. Its initial setting time is 420 min and its final setting time is 470 min.

[0062] (5) The paste obtained in step (4) is injected into a 10mm×10mm×10mm cube mold and sealed. After curing under natural conditions for 3 days, 7 days and 28 days respectively, the uniaxial compressive strength of the concrete building materials is 12.6MPa, 18.7MPa and 31.9MPa respectively.

[0063] Example 2

[0064] In this embodiment, the external carbon source 5 is liquid carbon dioxide (tank truck, storage tank) at 2.74 MPa and -40°C; or dry aerosol carbon dioxide (-40 to -20°C; <0.7 MPa) formed by depressurizing liquid carbon dioxide through shut-off valve 111, which is input into the long-distance gas buffer device 12 as a carbon source through pipeline.

[0065] like Figure 4 As shown, one of the two carbon sources enters the long-distance heat exchange tube 121 (carbon dioxide processing capacity is 500 Nm). 3 / h, made of stainless steel) fully heat exchanged and vaporized to form gaseous carbon dioxide. After heat exchange, the gaseous carbon dioxide enters the pressure reducing valve group 122 to control the pressure at 1.2~1.5MPa. Specifically, the pressure reducing valve group 122 consists of four DN40 ball valves and two self-operated pressure regulating valves, and safety valves and pressure gauges are installed at both the inlet and outlet. The inlet pressure is designed to be 2.5MPa.

[0066] After being depressurized, gaseous carbon dioxide enters a gaseous buffer tank 123 with a design pressure of 2MPa for pressure stabilization, and outputs gaseous carbon dioxide at a stable pressure. Specifically, a pressure reducing valve with a pressure of 0 to 1.2MPa is connected to the rear end of the gaseous buffer tank 123.

[0067] This embodiment uses concrete production module 3 as an example to illustrate the impact of this system on the precast block production process and block performance:

[0068] (1) Mix the above raw materials in the raw material processing module 2 according to the ratio of 200 parts fly ash, 400 parts steel slag, 250 parts calcium carbide slag, 70 parts cement and 80 parts gravel per ton of block, and further press them into mineralized curing blocks of 240mm×115mm×53mm.

[0069] (2) After the blocks are formed, they are sent into the pre-curing chamber. Based on the temperature and humidity environment of 21°C and 63%RH in the pre-curing chamber, they are pre-cured for 24 hours and then transferred to the concrete production module 3 for mineralization curing. The stable pressure of gaseous carbon dioxide obtained in the above steps is input to reach the preset pressure of 0.9MPa. The mineralization curing time lasts for 4 hours to obtain precast blocks.

[0070] The precast blocks had an average carbon fixation rate of 5.7% and a water absorption rate of 11%, reaching water saturation after 48 hours in water. Immersion performance tests showed a slight increase in strength within 28 days of immersion, with no strength loss. The compressive strength reached 15.4 MPa at 28 days, meeting the strength requirements of the MU15 national standard.

[0071] Example 3

[0072] In this embodiment, the external carbon source 5 is gaseous carbon dioxide with a pressure greater than 1 MPa, which can come from the gaseous buffer tank 123 in this system or other industrial gas sources (such as carbon dioxide capture in coal-fired power plants, carbon dioxide purification in coal chemical plants, carbon dioxide capture in steel plants, etc.).

[0073] like Figure 5 As shown, gaseous carbon dioxide is pressurized by the gas storage tank 131 and then enters the dissolving and stirring tank 132 through the gas inlet pipe. The gas inlet pipe includes a pressure reducing and regulating device, which can precisely control the pressure of the gaseous carbon dioxide injected into the dissolving and stirring tank 132. The carbon dioxide is rapidly injected into the dissolving and stirring tank 132 within 5 seconds to reach the specified pressure and maintain the pressure for more than 30 seconds.

[0074] Specifically, the solute in the dissolving and stirring tank is water (or other working fluids, such as saturated calcium hydroxide solution, sodium hydroxide solution, etc.), and carbon dioxide is injected within 5 seconds to reach 0.5 MPa, and the pressure is maintained for more than 30 seconds to obtain dissolved carbon dioxide with a solubility of 7.22 g / L.

[0075] After the dissolved carbon dioxide stabilizes, it is depressurized through the outlet to atmospheric pressure and then output.

[0076] It should be noted that, since the dissolved carbon dioxide in the dissolving and stirring tank 132 is unstable and easily decomposes, a pressure regulating valve 133 is installed to control the pressure in the dissolving and stirring tank 132.

[0077] In addition, during and after the operation of the pressure dissolution device 13, excess gas (exhaust gas) is recovered to the gaseous buffer tank 123 through the pressure regulating valve 133.

[0078] This embodiment uses concrete production module 3 as an example to illustrate the impact of this system on the slurry production process and concrete performance:

[0079] (1) Coarse aggregate, fine aggregate, cement, auxiliary cementitious materials, and carbonation additives are thoroughly mixed in the raw material processing module 2 in a mass ratio of 880 parts: 880 parts: 200 parts: 160 parts: 8 parts;

[0080] (2) The premixed powder in step (1) is transported to the multi-point microcrystalline mineralization reactor in the concrete production module 3. 185 parts of dissolved carbon dioxide obtained in the above steps are introduced from the top of the reactor and stirred continuously at 30 rpm for 120 seconds until the reaction is completed, resulting in a paste-like slurry with a slump of 161 mm. Its initial setting time is 300 min and its final setting time is 360 min.

[0081] (3) The paste obtained in step (2) is injected into a 10mm×10mm×10mm cube mold and sealed. After curing under natural conditions for 3 days, 7 days and 28 days respectively, the uniaxial compressive strength of the concrete building materials is 20.7MPa, 26.3MPa and 37.1MPa respectively, which meet the strength requirements of C35 national standard concrete.

[0082] The embodiments described above provide a detailed explanation of the technical solutions of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, additions, or similar substitutions made within the scope of the principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A concrete building material production system based on multi-point microcrystalline mineralization of composite carbon dioxide, characterized in that, It includes a composite carbon dioxide generation module (1), a raw material processing module (2), a concrete production module (3), and an external carbon source (5); The composite carbon dioxide generation module (1) includes a short-range phase separation device (11), a long-range gaseous buffer device (12), and a pressure dissolution device (13); wherein, the short-range phase separation device (11) is used to convert liquid carbon dioxide into wet aerosol carbon dioxide, the long-range gaseous buffer device (12) is used to convert liquid carbon dioxide or dry aerosol carbon dioxide into gaseous carbon dioxide at stable pressure; and the pressure dissolution device (13) is used to convert gaseous carbon dioxide into dissolved carbon dioxide. The carbon source from the external carbon source (5) is processed by the composite carbon dioxide generation module (1) and then outputs carbon dioxide in the state required by the corresponding module to the raw material processing module (2) or the concrete production module (3); precast building materials or slurry are prepared by the raw material processing module (2) and the concrete production module (3), and the precast building materials or slurry are further used to prepare finished concrete building materials. The short-range phase separation device (11) includes a shut-off valve (111), a humidification chamber (112), and a steam / humidity generator (113). The dry aerosol carbon dioxide formed after the liquid carbon dioxide is depressurized through the shut-off valve (111) is input into the long-range gas buffer device (12) through the pipeline, or input into the humidification chamber (112) for phase separation and then output stable wet aerosol carbon dioxide. The long-range gaseous buffer device (12) includes a long-range heat exchange tube (121), a pressure reducing valve group (122), and a gaseous buffer tank (123) connected in sequence. Dry aerosol carbon dioxide from the shut-off valve (111) or liquid carbon dioxide from the external carbon source (5) is heat exchanged through the long-range heat exchange tube (121) and pressure reduced by the pressure reducing valve group (122) before entering the gaseous buffer tank (123) for pressure stabilization, and outputting gaseous carbon dioxide at a stable pressure. The pressure dissolving device (13) includes a gas storage tank (131), a dissolving and stirring tank (132), and a pressure regulating valve (133); gaseous carbon dioxide from the gaseous buffer tank (123) or an external carbon source (5) is pressurized by the gas storage tank (131) and then input into the dissolving and stirring tank (132) containing solvent, where pressure is applied and stirring is performed to output dissolved carbon dioxide; The raw material processing module (2) is connected to the long-range gaseous buffer device (12) through a pipeline; the raw material processing module (2) receives gaseous carbon dioxide at a stable pressure output by the long-range gaseous buffer device (12) to pre-treat the building material raw materials. The pre-treatment operation includes strengthening the building material raw materials. The strengthening method is mechanical activation wet multi-point microcrystalline mineralization strengthening. The concrete production module (3) is connected to the short-range phase separation device (11), the long-range gaseous buffer device (12), and the pressure dissolving device (13) through pipelines. The concrete production module (3) receives the wet aerosol carbon dioxide output from the short-range phase separation device (11), or receives the gaseous carbon dioxide at stable pressure output from the long-range gaseous buffer device (12), or receives the dissolved carbon dioxide output from the pressure dissolving device (13). The wet aerosol carbon dioxide, the gaseous carbon dioxide at stable pressure, or the dissolved carbon dioxide and the building material raw materials transported by the raw material processing module (2) are used to carry out a multi-point microcrystalline mineralization reaction to prepare precast building materials or slurry.

2. The concrete building material production system based on multi-point microcrystalline mineralization of composite carbon dioxide according to claim 1, characterized in that, It also includes a mobile strengthening module (4); the carbon source from the external carbon source (5) is processed by the composite carbon dioxide generation module (1) and then outputs carbon dioxide in the state required by the corresponding module to the raw material processing module (2), the concrete production module (3) or the mobile strengthening module (4); the mobile strengthening module (4) further processes the slurry prepared by the concrete production module (3) into finished concrete building materials.

3. The concrete building material production system based on multi-point microcrystalline mineralization of composite carbon dioxide according to claim 1, characterized in that, The pressure regulating valve (133) ensures that the internal pressure of the dissolving and stirring tank (132) is stable.

4. The concrete building material production system based on multi-point microcrystalline mineralization of composite carbon dioxide according to claim 1, characterized in that, The building material raw materials include silicate cement, alkaline-neutral industrial solid waste, building material aggregates, or carbonated active cementitious materials.

5. The concrete building material production system based on multi-point microcrystalline mineralization of composite carbon dioxide according to claim 2, characterized in that, The mobile strengthening module (4) is connected to the short-range phase separation device (11) and the pressure dissolving device (13) through pipelines respectively; the mobile strengthening module (4) receives the wet aerosol carbon dioxide output by the short-range phase separation device (11) or the dissolved carbon dioxide output by the pressure dissolving device (13), so that the slurry and the wet aerosol carbon dioxide or dissolved carbon dioxide undergo a multi-point microcrystalline mineralization reaction to prepare the finished concrete building material.

6. The concrete building material production system based on multi-point microcrystalline mineralization of composite carbon dioxide according to claim 2, characterized in that, The mobile reinforcement module (4) is a concrete mixer truck.

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