System and method for low-pressure suspension carbonation modification of powdery material combined with emission reduction of industrial flue gas co 2

Abstract

Disclosed in the present invention are a system and method for low-pressure suspension carbonation modification of a powdery material combined with emission reduction of industrial flue gas CO2, comprising a low-pressure suspension carbonation bed system, a bag dust collector, and an induced draft fan. The low-pressure suspension carbonation bed system comprises an air duct, a suspension carbonation bed, and a water spraying system. High-temperature and high-CO2 flue gas and powdery material are sprayed upward into the suspension carbonation bed, and water or an aqueous solution of a carbonation aid is sprayed into the suspension carbonation bed in the form of droplets, so that the water vapor in the flue gas forms a critical saturation state, forming a liquid film on the surface of the material. The CO2 in the flue gas dissolves into the liquid film to undergo a carbonation reaction with the material. The flue gas carries the material and enters the bag dust collector, where part of the collected powder returns to the low-pressure suspension carbonation bed system for cyclic carbonation, and part is used as a modified carbonated material. The present invention achieves sufficient carbonation of powdery material and flue gas in a suspended state, improves the carbonation rate, reduces the emission of CO2 in the flue gas, and is conducive to large-scale and continuous production of material carbonation processes.

Description

System and method for low-pressure suspended carbonization modification combined with industrial flue gas CO2 emission reduction of powdery material TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon emission reduction, in particular to a system and method for low-pressure suspended carbonization modification combined with industrial flue gas CO2 emission reduction of powdery material. BACKGROUND

[0002] Cement production consumes a large amount of natural resources and emits a large amount of carbon dioxide. The cement industry is the third largest source of carbon dioxide emissions in China, accounting for about 13% of the total industrial carbon emissions. In 2022, China's cement production reached 2.118 billion tons, and carbon dioxide emissions were about 1.3 billion tons. Therefore, carbon emission reduction in the domestic cement industry is related to the realization of the carbon peak and carbon neutral strategic goals. For this reason, the academic and industrial circles have proposed and adopted various energy-saving and emission-reducing strategies, such as reducing the amount of cement in concrete, reducing the clinker coefficient in cement, reducing carbon emissions in the cement clinker production process, using new types of biomass fuel, carbon capture, utilization and storage, etc.

[0003] The existing general-purpose cement is mainly ordinary portland cement, and its main mineral components are C3S, C2S, C3A, C4AF, etc. Through water mixing and hydration reaction, it is made into a cementitious material. The raw material of ordinary portland cement is mainly limestone, and the production of 1 ton of ordinary portland cement clinker requires about 1.2 tons of limestone, producing about 500 kg of CO2 emissions, accounting for about 60% of the total carbon emissions in the cement production process. In order to reduce carbon emissions in cement production, developing new carbonizable low-calcium low-carbon cement varieties is an important way to reduce the consumption of calcium carbonate raw materials on the one hand, and to capture part of the CO2 in the cement carbonization process on the other hand. However, due to the application of carbonizable low-carbon cement mainly in the concrete product industry, this has seriously restricted the popularization and application of this technology. Therefore, if the new carbonizable low-carbon clinker is prepared into a high-activity auxiliary cementitious material and used in cement and concrete, the prepared cement and concrete become negative carbon cement and concrete, which solves the application range of carbonizable new low-carbon cement and will also become one of the effective paths for the cement industry to reduce carbon emissions.

[0004] At present, most of the reports on carbonizable low calcium and low carbon cement are still in the laboratory research stage. In the Low-CO2 synthetic SCMs published by Solida Technology in the International Cement Review magazine, it is mentioned that the use of low-carbon clinker mainly composed of carbonizable minerals to prepare SCM materials in the slurry or semi-wet state by passing industrial tail gas containing carbon dioxide. The low-carbon clinker used mainly contains CS and C3S2, which basically do not hydrate with water but can carbonize with carbon dioxide to form calcite and amorphous silicon dioxide. The literature of Solida Company mentioned that the SCM prepared contains a lot of calcite products. However, GB175-2021 "General Portland Cement" standard has a clear requirement for the loss on ignition of cement. If the SCM content is 30%, full carbonization can form about 15% calcite. Since the limestone content of PⅡ Portland cement is ≤5%, the loss on ignition of Portland cement (PⅠ and PⅡ) is less than 3.0% and 3.5% respectively, and the loss on ignition of ordinary Portland cement is ≤5.0%, and the loss on ignition of fly ash as a mixing material in GB / T1596-2017 "Fly Ash for Use in Cement and Concrete" standard is ≤8.0%, which seriously limits the dosage range of SCM materials prepared by full carbonization. Steel slag must be fully carbonized to solve the problem of poor soundness. Even if the appropriate carbonization can be achieved under this technology, the SCM material obtained is mainly calcite, and its activity is much lower than that of amorphous calcium carbonate or poorly crystalline barite, spherulite, etc.

[0005] Low-carbon cement has broad application prospects in the field of carbon emission reduction. However, there are currently no reports on industrial-grade carbonization methods and systems for low-carbon cement. Current research focuses relatively more on the carbonization of steel slag. The mineral composition of steel slag is mainly C2S, C4AF, and a large amount of free CaO. Steel slag is an industrial waste generated during the steelmaking process. Using steel slag to make auxiliary cementitious materials to replace cement clinker can reduce the unit carbon emissions of cement. Chinese Patent Publication No. CN113072311A discloses a steel slag auxiliary cementitious material, its preparation method, and its application. It mentions using industrial exhaust gas to carbonize steel slag powder, and introducing industrial exhaust gas containing a carbon dioxide concentration of 20% during the grinding process. However, due to the limited volume of the grinding equipment and the short residence time of the flue gas in the mill, the carbonization reaction only occurs inside the mill, making it difficult to fully carbonize the steel slag, and the carbonization process is uncontrollable. Chinese Patent Publication No. CN214571715U discloses a heating and pressurizing device for carbonizing steel slag in tailings test blocks. By controlling temperature and carbon dioxide gas pressure, the carbonization rate is significantly increased, greatly accelerating the reaction process and improving the comprehensive utilization of steel slag and carbon dioxide. However, due to limitations imposed by the pressure vessel volume and feeding method, this pressurized carbonization method is difficult to scale up industrially and for continuous production.

[0006] In summary, the problems with existing technologies are:

[0007] (1) Existing pressure carbonization methods are difficult to meet the needs of large-scale production and continuous operation of the production process.

[0008] (2) Existing in-mill carbonization methods have short reaction residence time, insufficient carbonization reaction, uncontrollable carbonization process, low activity of carbonized materials, and cannot fully capture CO2 in flue gas.

[0009] Therefore, under the global carbon emission reduction situation, there is an urgent need to develop a new process method that is suitable for large-scale continuous industrial production, has a high carbonization rate, is process-controllable, and produces carbonized materials with high activity.

[0010] Summary of the Invention

[0011] To address the problems existing in the prior art, this invention provides a system and method for low-pressure suspension carbonization modification of powdered materials to jointly reduce CO2 emissions from industrial flue gas, achieving full carbonization of powdered materials and high-temperature, high-CO2 flue gas in a suspended state.

[0012] The present invention is implemented as follows: a system for low-pressure suspension carbonization modification of powdered materials to reduce CO2 emissions from industrial flue gas, comprising a low-pressure suspension carbonization bed system, a bag dust collector, and an induced draft fan;

[0013] The low-pressure suspension carbonization bed system comprises a wind pipe, a suspension carbonization bed and a water spraying system, the wind pipe is located below the suspension carbonization bed, the bottom of the wind pipe is a flue gas inlet, the flue gas inlet is connected to high-temperature high-CO2 flue gas, the material inlet of the low-pressure suspension carbonization bed system is arranged on the wind pipe or the suspension carbonization bed, so that the powdery material moves upward under the driving of the flue gas, the top end of the wind pipe is connected to the bottom end of the suspension carbonization bed, a spouting pipe is arranged at the connecting position, so that the high-temperature high-CO2 flue gas is spouted into the suspension carbonization bed, a plurality of branch spray guns are arranged at the lower part of the suspension carbonization bed and above the spouting pipe, the outlet of the water spraying system is connected to the inlet of the spray gun, so that the aqueous solution is spouted into the suspension carbonization bed in the form of mist droplets, the water vapor in the flue gas in the suspension carbonization bed forms a critical saturation state of water vapor-mist droplets, and a liquid film is formed on the surface of the material.

[0014] The outlet of the suspension carbonization bed is connected to the flue gas inlet of the bag dust collector, the material outlet of the bag dust collector is connected to the carbonized material product place, or is respectively connected to the carbonized material product place and the material inlet of the low-pressure suspension carbonization bed system, and the flue gas outlet of the bag dust collector is connected to the inlet of the induced draft fan.

[0015] In the above technical solution, preferably, the suspension carbonization bed comprises a spouting pipe, a carbonization bed cone and a carbonization bed column which are sequentially connected from bottom to top, the spouting pipe is a vertical pipe, and a flow guide device for uniformly distributing the flue gas is arranged in the spouting pipe, the flow guide device is a flow guide plate, a grid or a flow guide ring.

[0016] In the above technical solution, further preferably, an ultrasonic generator is arranged at the carbonization bed cone.

[0017] In the above technical solution, preferably, a secondary temperature control mixing chamber is arranged between the suspension carbonization bed and the bag dust collector, the secondary temperature control mixing chamber is used for increasing the temperature and reducing the humidity of the flue gas out of the suspension carbonization bed, the secondary temperature control mixing chamber has an inlet one, an inlet two and an outlet, the top outlet of the suspension carbonization bed is connected to the inlet one of the secondary temperature control mixing chamber, the inlet two of the secondary temperature control mixing chamber is connected to high-temperature high-CO2 flue gas, and the outlet of the secondary temperature control mixing chamber is connected to the flue gas inlet of the bag dust collector.

[0018] In the above technical solution, preferably, a temperature measuring device is arranged on the outlet pipeline of the secondary temperature control mixing chamber.

[0019] In the above technical solution, preferably, a powder separation device is arranged between the secondary temperature control mixing chamber and the bag dust collector, the outlet of the secondary temperature control mixing chamber is connected to the flue gas inlet of the powder separation device, the bottom material outlet of the powder separation device is connected to the material inlet of the low-pressure suspension carbonization bed system, and the top flue gas outlet of the powder separation device is connected to the flue gas inlet of the bag dust collector.

[0020] In the technical scheme, preferably, the powder separation device is a powder concentrator or a cyclone, which is used to separate coarse powder and fine powder from the material.

[0021] In the technical scheme, preferably, a lock valve and a distribution valve are sequentially arranged on a material pipe of a bottom material outlet of the powder separation device, and the bottom material outlet of the powder separation device is connected to the carbonized material product through the distribution valve, so that the coarse powder discharged from the powder separation device can enter the suspended carbonization bed and the carbonized material product respectively.

[0022] In the technical scheme, preferably, a filter bag is vertically arranged in the bag dust collector, and a compressed air blowing device for regularly cleaning the surface of the filter bag is arranged in the bag dust collector.

[0023] A method for low-pressure suspended carbonization modification of powdery material to reduce CO2 in industrial flue gas, comprising the following steps:

[0024] suspended carbonization:

[0025] The high-temperature high-CO2 flue gas is introduced through the flue gas inlet of the air pipe, the temperature of the high-temperature high-CO2 flue gas is 100-300℃, and the CO2 concentration is ≥10%, the high-temperature high-CO2 flue gas moves upward and is sprayed into the suspended carbonization bed through the spouting pipe; at the same time, the powdery material with a temperature ≤60℃ and an average particle size less than 200μm is dispersed and fed into the air pipe or the suspended carbonization bed, so that the material is suspended in the high-temperature high-CO2 flue gas under the action of the airflow drag; the pressure in the suspended carbonization bed is 0-3000Pa, and the average wind speed in the cross section of the suspended carbonization bed is 3-10m / s; at the same time, water or a carbonization aid aqueous solution is sprayed into the suspended carbonization bed in the form of mist droplets through the spray gun, so that the water vapor in the flue gas forms a critical saturation state, the water vapor forms a liquid film on the surface of the material, and the CO2 in the flue gas dissolves into the liquid film and reacts with the material to form carbonization;

[0026] material powder circulation and product collection:

[0027] The flue gas carrying the material out of the suspended carbonization bed enters the bag dust collector under the suction of the induced draft fan, and after the material is collected, part of the material is returned to the low-pressure suspended carbonization bed system for circulation carbonization, and part of the material is led to the carbonized material product; or, all of the material is led to the carbonized material product.

[0028] In the technical scheme, preferably, the flue gas carrying the material out of the suspended carbonization bed first enters the secondary temperature control mixing chamber and mixes with the high-temperature high-CO2 flue gas, and then enters the bag dust collector; the temperature of the flue gas out of the secondary temperature control mixing chamber is controlled to be ≥90℃.

[0029] In the above technical solution, preferably, the flue gas carrying the material from the secondary temperature control mixing chamber first enters the powder separation device, the coarse powder in the material is collected and discharged from the bottom of the powder separation device, part of which is returned to the low-pressure suspended carbonization bed system for circulating carbonization, and part of which is introduced to the carbonized material product; the fine powder is discharged from the top of the powder separation device into the bag dust collector along with the flue gas, the flue gas passes through the filter bag, the filtration wind speed is 0.5-1.5 m / min, the fine powder forms a powder cake on the surface of the filter bag, and the CO2 in the flue gas continues to react with the material during the process of passing through the powder cake, and the powder cake is cleaned by periodically blowing compressed air, and the powder collected from the bag dust collector is the carbonized fine powder material, which is introduced to the carbonized material product.

[0030] In the above technical solution, preferably, an ultrasonic vibration is additionally arranged at the bottom of the suspended carbonization bed during the suspended carbonization process.

[0031] In the above technical solution, preferably, the carbonization aid in the aqueous solution is one or a combination of any two of lignin sulfonate, polycyclic aromatic salt, water-soluble resin sulfonate and alcohol amine organic matter.

[0032] In the above technical solution, preferably, the powdered material is one or a combination of any two of cement clinker, alumina clinker, magnesia clinker, spodumene sintered material, steel slag, slag and recycled concrete aggregate.

[0033] The present application has the advantages and positive effects that:

[0034] (1) The present application sets up a low-pressure suspended carbonization bed system, realizes the gas-solid fluidization mixing in the suspended carbonization bed, improves the carbonization reaction rate, and the low-pressure working condition environment in the suspended carbonization bed creates conditions for continuous production; and after the carbonization aid aqueous solution is sprayed into the suspended carbonization bed, the liquid film is formed on the particle surface in the form of mist droplets, the liquid film acts as a carbonization reaction gas-solid mass transfer bridge, which can accelerate the carbonization speed; at the same time, water or carbonization aid aqueous solution with crystal form control agent is sprayed into the suspended carbonization bed, which promotes the full coverage of the particle surface by water or crystal form control agent, reduces the generation of calcite, increases the amorphous calcium carbonate, and improves the activity of the carbonized material.

[0035] (2) The present application solves the problem of condensation caused by the decrease of the dew point of the flue gas out of the suspended carbonization bed due to the spraying of water or carbonization aid aqueous solution during the carbonization process by introducing high-temperature high-CO2 flue gas secondary temperature control, which improves the water spraying amount in the suspended carbonization bed and is conducive to further carbonization; and the introduction of high-temperature high-CO2 flue gas secondary temperature control increases the CO2 concentration, which is conducive to the carbonization along the pipeline and the bag dust collector; and the fine powder is attached to the surface of the filter bag during the dust collection of the bag dust collector, and the CO2 gas can continue to carbonize the fine powder during the process of penetrating the filter bag.

[0036] (3) The ultrasonic generator is arranged at the bottom of the suspended carbonization bed of the application, and the particle agglomeration is reduced by high-frequency acoustic vibration, which is beneficial to subsequent operations.

[0037] (4) The coarse powder is returned to the low-pressure suspended carbonization bed system through the powder separation process, which avoids the problems of small specific surface area and low carbonization degree of the coarse powder, and realizes the cyclic carbonization, which improves the carbonization rate. BRIEF DESCRIPTION OF DRAWINGS

[0038] Fig. 1 is a schematic diagram of a system for low-pressure suspended carbonization modification combined with CO2 emission reduction of industrial flue gas of powdery material according to the embodiment 1 of the application;

[0039] Fig. 2 is a process flow diagram of a system for low-pressure suspended carbonization modification combined with CO2 emission reduction of industrial flue gas of powdery material according to the embodiment 1 of the application;

[0040] Fig. 3 is a schematic diagram of the position relationship among calcium-based powdery material, liquid film and flue gas in the suspended carbonization bed.

[0041] Fig. 4 is a schematic diagram of a system for low-pressure suspended carbonization modification combined with CO2 emission reduction of industrial flue gas of powdery material according to the embodiment 2 of the application;

[0042] Fig. 5 is a process flow diagram of a system for low-pressure suspended carbonization modification combined with CO2 emission reduction of industrial flue gas of powdery material according to the embodiment 2 of the application.

[0043] Fig. 4 is a schematic diagram of a system for low-pressure suspended carbonization modification combined with CO2 emission reduction of industrial flue gas of powdery material according to the embodiment 2 of the application;

[0044] 1 - low-pressure suspended carbonization bed system; 101 - spouting pipeline; 102 - carbonization bed cone; 103 - carbonization bed column; 104 - ultrasonic generator; 105 - water spraying system; 106 - lance; 107 - air pipe;

[0045] 2 - bag dust collector; 201 - filter bag;

[0046] 3 - induced draft fan;

[0047] 4 - secondary temperature control mixing chamber; 401 - temperature measuring device;

[0048] 5 - powder separation device; 501 - air lock valve; 502 - material distribution valve;

[0049] The arrowed dashed line is the gas flow direction, and the arrowed solid line is the material flow direction. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0051] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0052] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0053] Embodiment 1

[0054] Please refer to FIG. 1 and FIG. 2, the embodiment of the present application provides a system for low-pressure suspension carbonation modification combined with CO2 emission reduction of industrial flue gas, which comprises a low-pressure suspension carbonation bed system 1, a bag dust collector 2 and an induced draft fan 3. The powdered material M1 is cement clinker, alumina clinker, magnesia clinker, spodumene sintered material, steel slag, slag, etc. The present system can be used for carbonation of low-carbon cement clinker and other types of clinker, and also for carbonation of steel slag and slag.

[0055] The low-pressure suspension carbonation bed system 1 comprises a wind pipe 107, a suspension carbonation bed and a water spraying system 105. The wind pipe 107 is located below the suspension carbonation bed, and the bottom of the wind pipe 107 is a flue gas inlet. High-temperature high-CO2 flue gas is introduced into the flue gas inlet, and the CO2 concentration in the high-temperature high-CO2 flue gas is ≥10%. A material inlet is arranged on the wind pipe 107 or the suspension carbonation bed. In this embodiment, the material inlet is arranged on the wind pipe 107, so that the powdered material M1 moves upward under the action of the flue gas. The top end of the wind pipe 107 is connected with the bottom end of the suspension carbonation bed, and a spouting pipe 101 is arranged at the connection position, so that the high-temperature high-CO2 flue gas carrying the material is spouted into the suspension carbonation bed.

[0056] The lower part of the suspension carbonization bed is provided with several branch spray guns 106 and is located above the spray pipe 101. The solution outlet of the water spraying system 105 is connected with the inlet of the spray gun 106, so that the water solution is sprayed into the suspension carbonization bed in the form of mist droplets. The water vapor in the flue gas in the suspension carbonization bed forms a water vapor-water droplet critical saturation state, and a liquid film B is formed on the surface of the material particles A, as shown in FIG. 3.

[0057] The outlet of the suspension carbonization bed is connected with the flue gas inlet of the bag dust collector 2. The material outlet of the bag dust collector 2 is divided into two routes, one of which is connected with the carbonized material product, and the other of which is connected with the air pipe 107 or the material inlet of the suspension carbonization bed. The collected material is continuously returned to the air pipe 107 or the suspension carbonization bed. In this embodiment, the part of the material collected by the bag dust collector 2 is continuously returned to the air pipe 107 for circulation carbonization. The flue gas outlet of the bag dust collector 2 is connected with the inlet of the induced draft fan 3, and the low CO2 flue gas Q2 is discharged.

[0058] As a preferred embodiment, the suspension carbonization bed comprises, from bottom to top, a spray pipe 101, a carbonization bed cone 102, and a carbonization bed column 103 connected in sequence. The spray pipe 101 is a vertical pipe, and a flow guide device for uniformly distributing flue gas and material is arranged inside the spray pipe. The flow guide device is a flow guide plate, a grid, or a flow guide ring structure.

[0059] The bag dust collector 2 is internally provided with a vertically placed filter bag 201 and a compressed air blowing device for periodically cleaning the filter bag surface powder cake. The material outlet of the bag dust collector 2 is connected with the carbonized material product and the material inlet of the air pipe 107. The flue gas outlet of the bag dust collector 2 is connected with the inlet of the induced draft fan 3.

[0060] The method for low-pressure suspension carbonization modification combined with industrial flue gas CO2 emission reduction of powdery material comprises the following steps:

[0061] Suspension carbonization:

[0062] The high-temperature high-CO2 flue gas is introduced into the flue gas inlet of the air duct 107, and the temperature of the high-temperature high-CO2 flue gas Q1 in the air duct is 100-150℃, and the CO2 concentration is ≥10%; at the same time, the powdery material M1 is dispersed and fed into the air duct 107 by a material scattering device, so that the material is suspended in the high-temperature high-CO2 flue gas under the action of the gas flow drag force, the high-temperature high-CO2 flue gas carrying the material moves upward, and is sprayed into the suspended carbonation bed through the spouting pipe 101; the pressure in the suspended carbonation bed is 0-3000Pa, and the average cross-sectional wind speed in the suspended carbonation bed is 3-10m / s; at the same time, water or a carbonation aid aqueous solution is sprayed into the suspended carbonation bed in the form of mist droplets through the spray gun 106, so that the water vapor in the flue gas is in a critical saturated state (relative humidity ≥90%); at the same time, since the surface temperature of the material is lower than the dew point temperature of the water vapor, the water vapor condenses on the surface of the material to form a liquid film, the liquid film provides a transport medium in the gas-solid carbonation reaction, the CO2 in the flue gas is dissolved into the liquid film to react with the material to accelerate the carbonation process; wherein the temperature of the powdery material M1 is ≤60℃, and the average particle size is less than 80μm.

[0063] In the carbonation aid aqueous solution, the carbonation aid is one or a combination of any two of lignin sulfonate, polycyclic aromatic salt, water-soluble resin sulfonate and alcohol amine organic matter.

[0064] Material powder circulation and finished product collection:

[0065] The flue gas carrying the material out of the suspended carbonation bed enters the bag dust collector 2 under the suction of the induced draft fan 3, the material is collected, a part of the powder is returned to the air duct 107 of the low-pressure suspended carbonation bed system 1 as the circulating material M3 out of the bag dust collector to be recycled and carbonated, and a part is introduced to the carbonation material finished product as the first-stage finished product M2; the flue gas discharged from the bag dust collector is low-CO2 flue gas Q2.

[0066] The carbonation materials obtained by low-pressure suspended carbonation modification of cement clinker, alumina clinker, magnesia clinker, lithium aluminosilicate sintered material, steel slag and slag are carbonates such as calcium carbonate, aluminum carbonate, magnesium carbonate and lithium carbonate or mixtures containing carbonates.

[0067] Example 2

[0068] Please refer to FIG. 4 and FIG. 5, the embodiment of the present application provides a system for low-pressure suspended carbonation modification of powdery material and combined reduction of CO2 in industrial flue gas, which comprises a low-pressure suspended carbonation bed system 1, a secondary temperature control mixer 4, a powder separation device 5, a bag dust collector 2 and an induced draft fan 3. The powdery material M1 is cement clinker, alumina clinker, magnesia clinker, lithium aluminosilicate sintered material, steel slag, slag and the like, and the system can be used for carbonation of low-carbon cement clinker and other types of clinker, and also can be used for carbonation of steel slag, slag and the like.

[0069] The structure of the low-pressure suspended carbonization bed system 1 is the same as that of embodiment 1, and the difference from embodiment 1 is that an ultrasonic generator 104 is additionally arranged at the carbonization bed cone 102, and the ultrasonic generator 104 is located below the entrance of the lance 106.

[0070] The secondary temperature control mixing chamber 4 is located between the suspended carbonization bed and the powder separation device 5, and is used to increase the temperature of the flue gas discharged from the suspended carbonization bed and reduce the humidity of the flue gas. The secondary temperature control mixing chamber 4 has an inlet one, an inlet two and an outlet, the top outlet of the suspended carbonization bed is connected with the inlet one of the secondary temperature control mixing chamber 4, the inlet two of the secondary temperature control mixing chamber 4 is connected with high-temperature high-CO2 flue gas, and the outlet of the secondary temperature control mixing chamber 4 is connected with the flue gas inlet of the powder separation device 5. A temperature measuring device 401 is arranged on the outlet pipeline of the secondary temperature control mixing chamber 4, and the temperature measuring device 401 is a thermocouple.

[0071] The powder separation device 5 is a powder separator or a cyclone, which is used to separate coarse powder and fine powder in the material. A lock valve 501 and a material distribution valve 502 are arranged on the material outlet pipeline of the bottom of the powder separation device 5 in sequence, and the material outlet of the bottom of the powder separation device 5 is connected with the material inlet of the air pipe 107 and the carbonized material product through the material distribution valve 502, so that the coarse powder discharged from the powder separation device 5 can enter the suspended carbonization bed and the carbonized material product respectively. The top flue gas outlet of the powder separation device 5 is connected with the flue gas inlet of the bag dust collector 2, and the bag dust collector 2 is internally provided with a vertically placed filter bag 201 and a compressed air blowing device for periodically cleaning the surface powder cake of the filter bag. The material outlet of the bag dust collector 2 is connected with the carbonized material product, and the flue gas outlet of the bag dust collector 2 is connected with the inlet of the induced draft fan 3.

[0072] The method for low-pressure suspended carbonization modification of powdery material combined with industrial flue gas CO2 emission reduction, comprising the following steps:

[0073] Suspended carbonization:

[0074] The high-temperature and high-CO2 flue gas is introduced into the air inlet of the air duct 107, and the temperature of the high-temperature and high-CO2 flue gas Q1 in the air duct is 100-150°C, and the CO2 concentration is ≥10%; at the same time, the powdery material M1 is dispersed and fed into the air duct 107 by a material scattering device, so that the material is suspended in the high-temperature and high-CO2 flue gas under the action of the gas flow drag force, the high-temperature and high-CO2 flue gas carrying the material moves upward, and is sprayed into the suspended carbonization bed through the spouting pipe 101; the pressure in the suspended carbonization bed is 0-3000 Pa, and the average wind speed in the cross section of the suspended carbonization bed is 3-10 m / s; at the same time, water or a carbonization aid aqueous solution is sprayed into the suspended carbonization bed in the form of mist droplets through the lance 106, so that the water vapor in the flue gas forms a critical saturation state (relative humidity ≥90%); at the same time, since the surface temperature of the material is lower than the dew point temperature of the water vapor, the water vapor condenses on the surface of the material to form a liquid film, the liquid film provides a transport medium in the gas-solid carbonization reaction, the CO2 in the flue gas is dissolved into the liquid film and reacts with the material to accelerate the carbonization process; wherein the temperature of the powdery material M1 is ≤60°C, and the average particle size is less than 200 μm.

[0075] In the suspended carbonization process, an ultrasonic vibration is additionally arranged at the bottom of the suspended carbonization bed. The high-frequency ultrasonic wave can accelerate the disturbance of the material at the bottom of the suspended carbonization bed and the flue gas flow, accelerate the reaction speed, reduce the particle agglomeration, promote the formation of the liquid film on the surface of the material and full coverage of the particle surface.

[0076] Material powder circulation:

[0077] The water vapor in the flue gas out of the suspended carbonization bed is close to a critical saturation state (relative humidity ≥90%), in order to avoid condensation in the subsequent powder separation device 5 and bag dust collector 2, a secondary temperature control mixing chamber 4 is arranged before the powder separation device 5, a part of the high-temperature and high-CO2 flue gas is introduced into the secondary temperature control mixing chamber 4, the temperature of the flue gas out of the suspended carbonization bed is raised, and the humidity of the flue gas is reduced.

[0078] The temperature of the flue gas carrying the material out of the suspended carbonization bed is 70-90°C, the flue gas carrying the material first enters the secondary temperature control mixing chamber 4 and is mixed with the high-temperature and high-CO2 flue gas Q3 introduced into the secondary temperature control mixing chamber, the temperature of the flue gas out of the secondary temperature control mixing chamber 4 is controlled to be ≥90°C, and then the flue gas enters the powder separation device 5, the coarse powder in the material is collected and discharged from the bottom of the powder separation device 5, and the fine powder is discharged from the top of the powder separation device with the flue gas. The coarse powder out of the powder separation device 5 is divided into two parts by a material distribution valve 502, one part is the circulating material M4 out of the powder separation device, is transported back to the air duct 107 through a material pipe, and then enters the suspended carbonization bed for circulating carbonization, and the other part is the second grade product M5 and is introduced to a carbonized material product place. The circulating ratio of the coarse powder in the suspended carbonization bed is controlled by the opening degree of the material distribution valve 502, so as to avoid the coarse powder which has been fully carbonized from being infinitely circulated in the suspended carbonization bed, thereby causing excessive circulating load and leading to the collapse of the suspended carbonization bed.

[0079] Product collection:

[0080] The flue gas and fine powder discharged from the top of the powder separation device 5 enters the bag filter 2 under the suction of the induced draft fan 3, the flue gas passes through the filter bag 201, the filtration wind speed is 0.5-1.5 m / min, the fine powder forms a powder cake on the surface of the filter bag, and the CO2 in the flue gas continues to react with the material during the process of passing through the powder cake, and the powder cake is cleaned by periodically blowing compressed air, the powder collected from the bag filter 2 is the first grade product M2, that is, the carbonated material after carbonation, the second grade product M5 and the first grade product M2 are introduced to the carbonated material product as the converged product M6, and the flue gas discharged from the bag filter is the low CO2 flue gas Q2.

[0081] The carbonated material obtained after the low-pressure suspension carbonation modification of the cement clinker, the alumina clinker, the magnesium oxide clinker, the lithium aluminosilicate sintered material, the steel slag and the slag is a carbonate such as calcium carbonate, aluminum carbonate, magnesium carbonate, lithium carbonate or a mixture containing the carbonate.

[0082] In order to better understand the above-mentioned embodiments of the present application, the following further describes them in combination with specific examples.

[0083] Example 1

[0084] In this example, low-carbon cement clinker is used as the carbonation raw material, and the process of preparing carbonated material by low-pressure suspension carbonation modification of low-carbon cement clinker powder combined with reduction of industrial flue gas CO2 is described in detail, as follows:

[0085] The low-carbon cement clinker has a mineral composition including: a'-C2S, C4A3$, C5S2$, CS, β-C2S, wherein the sum of the contents of a'-C2S and β-C2S accounts for more than 40% of the total mass of the low-carbon cement clinker, the sum of the contents of C4A3$ and C5S2$ accounts for more than 20% of the total mass of the low-carbon cement clinker, the content of CS accounts for more than 20% of the total mass of the low-carbon cement clinker, and the remaining part is a glass phase.

[0086] The particles with a particle size distribution of 5-200 μm in the low-carbon cement clinker powder account for more than 90%.

[0087] The high-temperature high-CO2 flue gas entering the suspension carbonation bed and the secondary temperature control mixing chamber 4 comes from the flue gas after the dust removal treatment of the cement production line, the temperature of the high-temperature high-CO2 flue gas is 100-150 ℃, and the CO2 concentration is 20%-30%.

[0088] The high-temperature high-CO2 flue gas Q1 is introduced through the flue gas inlet of the air duct 107, and the normal-temperature low-carbon cement clinker powder (≤60℃) is dispersed and fed into the air duct 107 through the material scattering device. Under the action of the gas flow drag force, the material is suspended in the flue gas, and the pressure in the suspended carbonization bed is 0 to -3000 Pa. The high-temperature high-CO2 flue gas Q1 and the powdered material M1 are sprayed into the suspended carbonization bed layer through the spouting pipe 101 at the bottom of the suspended carbonization bed and sprayed upward. The average wind speed in the cross section of the suspended carbonization bed is 3 to 10 m / s. The spouting pipe 101 is a vertical pipe, and a guide plate is arranged inside to promote the uniform distribution of the flue gas and the material. The ultrasonic generator 104 at the bottom of the suspended carbonization bed is turned on, and water or a carbonization aid aqueous solution in the water spraying system 105 is sprayed into the suspended carbonization bed in the form of mist droplets through the lance 106 at the carbonization bed cone 102. By adjusting the amount of the sprayed aqueous solution, the water vapor content in the flue gas is close to the critical saturation concentration.

[0089] Since the surface temperature of the material is lower than the dew point temperature of the water vapor, the water vapor condenses on the surface of the material particles A to form a liquid film B. The liquid film provides a transport medium in the gas-solid carbonization reaction. The CO2 in the flue gas C dissolves into the liquid film and reacts with the material, accelerating the carbonization process.

[0090] The main carbonization reactions are as follows:

[0091] The flue gas carrying the material out of the suspended carbonization bed enters the secondary temperature control mixing chamber 4 and is mixed with high-temperature high-CO2 flue gas, so that the temperature of the flue gas out of the secondary temperature control mixing chamber 4 is ≥90℃. Then the flue gas enters the powder separation device 5. The coarse powder is collected and discharged from the bottom of the powder separation device 5, and the fine powder is discharged from the top of the powder separation device with the flue gas and enters the bag dust collector.

[0092] The coarse powder out of the powder separation device 5 is partially returned to the air duct 107 for cyclic carbonization, and partially used as a carbonized material product. The powder collected by the bag dust collector 2 is used as a carbonized material product.

[0093] In order to improve the activity, the carbonization degree is moderate carbonization, and the carbonization rate of the low-carbon cement clinker powder is 10% to 20%.

[0094] Example 2

[0095] Different from example 1, in this example, steel slag is used as the carbonization raw material, and the steel slag micro-powder is low-pressure suspended carbonized and modified to jointly reduce the CO2 in the industrial flue gas and prepare carbonized materials.

[0096] The steel slag mainly includes C2S, C4AF, f-CaO and magnesium-iron phase solid solution, and also contains a small amount of C3S and f-MgO. The particle size distribution of the steel slag micro-powder is that the proportion of particles with a particle size of 5 to 200 um is greater than 85%.

[0097] The main carbonization reactions are as follows:

[0098] For steel slag, the carbonation rate of f-CaO needs to be improved, so as to solve the problem of poor stability caused by high f-CaO content when steel slag is used as carbonation material. The proportion of circulating carbonated steel slag powder is more than 80% through the opening adjustment of the distribution valve 502, the circulation ratio of coarse powder in the suspended carbonation bed 1 is improved, the carbonation time is prolonged, and the f-CaO in the steel slag is fully carbonated into CaCO3.

[0099] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing examples, or make equivalent replacement for part or all of the technical features, and these

Claims

1. A system for low pressure suspension carbonation modification combined abatement of CO2 from industrial flue gas of pulverized material, characterized in that: The system comprises a low-pressure suspended carbonization bed system, a bag filter and an induced draft fan. The low-pressure suspended carbonization bed system comprises a wind pipe, a suspended carbonization bed and a water spraying system, the wind pipe is located below the suspended carbonization bed, the bottom of the wind pipe is a flue gas inlet, the flue gas inlet is connected to high-temperature high-CO2 flue gas, the material inlet of the low-pressure suspended carbonization bed system is arranged on the wind pipe or the suspended carbonization bed, so that the powdery material moves upward under the driving of the flue gas, the top end of the wind pipe is connected to the bottom end of the suspended carbonization bed, and a spouting pipe is arranged at the connecting position, so that the high-temperature high-CO2 flue gas is spouted into the suspended carbonization bed, a plurality of branch spray guns are arranged at the lower part of the suspended carbonization bed and located above the spouting pipe, the outlet of the water spraying system is connected to the inlet of the spray gun, so that the aqueous solution is spouted into the suspended carbonization bed in the form of mist droplets, the water vapor in the flue gas in the suspended carbonization bed forms a critical saturation state of water vapor-mist droplets, and a liquid film is formed on the surface of the material. The outlet of the suspended carbonization bed is connected to the flue gas inlet of the bag filter, the material outlet of the bag filter is connected to the carbonized material product place, or respectively connected to the carbonized material product place and the material inlet of the low-pressure suspended carbonization bed system, and the flue gas outlet of the bag filter is connected to the inlet of the induced draft fan.

2. The system for low pressure suspension carbonation modification combined emission reduction of industrial flue gas CO2 of powdery materials according to claim 1, characterized in that: The suspended carbonization bed comprises a spouting pipe, a carbonization bed cone body and a carbonization bed column body which are sequentially connected from bottom to top, the spouting pipe is a vertical pipe, and a flow guide device for uniformly distributing flue gas is arranged in the spouting pipe.

3. The system for low pressure suspension carbonation modification combined emission reduction of industrial flue gas CO2 with powdery materials according to claim 2, characterized in that: An ultrasonic generator is arranged at the carbonization bed cone body.

4. The system for low pressure suspension carbonation modification combined emission reduction of industrial flue gas CO2 of powdery materials according to claim 1, characterized in that: A secondary temperature control mixing chamber is arranged between the suspended carbonization bed and the bag filter, the secondary temperature control mixing chamber is used for increasing the temperature and reducing the humidity of the flue gas from the suspended carbonization bed, the secondary temperature control mixing chamber has an inlet one, an inlet two and an outlet, the top outlet of the suspended carbonization bed is connected to the inlet one of the secondary temperature control mixing chamber, the inlet two of the secondary temperature control mixing chamber is connected to high-temperature high-CO2 flue gas, and the outlet of the secondary temperature control mixing chamber is connected to the flue gas inlet of the bag filter.

5. The system for low pressure suspension carbonation modification combined emission reduction of industrial flue gas CO2 with powdery materials according to claim 4, characterized in that: A temperature measuring device is arranged on the outlet pipeline of the secondary temperature control mixing chamber.

6. The system for low pressure suspension carbonation modification combined emission reduction of industrial flue gas CO2 with powdery materials according to claim 4, characterized in that: A powder separation device is arranged between the secondary temperature control mixing chamber and the bag filter, the outlet of the secondary temperature control mixing chamber is connected to the flue gas inlet of the powder separation device, the bottom material outlet of the powder separation device is connected to the material inlet of the low-pressure suspended carbonization bed system, and the top flue gas outlet of the powder separation device is connected to the flue gas inlet of the bag filter.

7. The system for low pressure suspension carbonation modification combined emission reduction of industrial flue gas CO2 with powdery materials according to claim 6, characterized in that: The powder separation device is a powder separator or a cyclone, which is used for separating coarse powder and fine powder in the material.

8. The system for low pressure suspension carbonation modification combined emission reduction of industrial flue gas CO2 with powdery materials according to claim 6, characterized in that: A lock valve and a material distribution valve are sequentially arranged on the material pipe of the bottom material outlet of the powder separation device, the bottom material outlet of the powder separation device is connected to the carbonized material product place through the material distribution valve, so that the coarse powder from the powder separation device can enter the suspended carbonization bed and the carbonized material product place respectively.

9. The system for low pressure suspension carbonation modification of CO2 emission from industrial flue gas with powdery material according to claim 1, characterized in that: A filter bag is vertically arranged in the bag filter, and a compressed air blowing device for regularly cleaning the surface powder cake of the filter bag is arranged in the bag filter. 10.A method for reducing CO2 in industrial flue gas by using the system according to any one of claims 1 to 9, comprising the following steps: suspended carbonization: The high-temperature high-CO2 flue gas is introduced through the flue gas inlet of the air duct, the high-temperature high-CO2 flue gas has a temperature of 100-300 DEG C and a CO2 concentration of 10% or more, the high-temperature high-CO2 flue gas moves upward and is sprayed into the suspended carbonization bed through the spouting pipe, at the same time, the powder material with a temperature of 60 DEG C or less and an average particle size of less than 200 microns is dispersed and fed into the air duct or the suspended carbonization bed, so that the material is suspended in the high-temperature high-CO2 flue gas under the action of the airflow drag, the pressure in the suspended carbonization bed is 0-3000 Pa, the average wind speed in the cross section of the suspended carbonization bed is 3-10 m / s, at the same time, the water or the carbonization aid aqueous solution is sprayed into the suspended carbonization bed in the form of mist droplets through the spray gun, so that the water vapor in the flue gas is in a critical saturated state, the water vapor forms a liquid film on the surface of the material, and the CO2 in the flue gas is dissolved into the liquid film and reacts with the material to form carbonization; Material powder circulation and finished product collection: The flue gas carrying the material out of the suspended carbonization bed enters the bag dust collector under the suction of the induced draft fan, the material is collected, part of the material is returned to the low-pressure suspended carbonization bed system for cyclic carbonization, and part of the material is introduced into the carbonized material finished product place; or, all of the material is introduced into the carbonized material finished product place.

11. The method for low pressure suspension carbonation modification combined emission reduction of industrial flue gas CO2 with powdery materials according to claim 10, characterized in that: The flue gas carrying the material out of the suspended carbonization bed first enters the secondary temperature control mixing chamber and is mixed with the high-temperature high-CO2 flue gas, and then enters the bag dust collector; the temperature of the flue gas out of the secondary temperature control mixing chamber is controlled to be 90 DEG C or more.

12. The method for low pressure suspension carbonation modification combined emission reduction of industrial flue gas CO2 with powdery materials according to claim 11, characterized in that: The flue gas carrying the material out of the secondary temperature control mixing chamber first enters the powder separation device, the coarse powder in the material is collected and discharged from the bottom of the powder separation device, part of the coarse powder is returned to the low-pressure suspended carbonization bed system for cyclic carbonization, and part of the coarse powder is introduced into the carbonized material finished product place; the fine powder is discharged from the top of the powder separation device and enters the bag dust collector, the flue gas passes through the filter bag, the filtration wind speed is 0.5-1.5 m / min, so that the fine powder forms a powder cake on the surface of the filter bag, the CO2 in the flue gas continues to react with the material during the process of passing through the powder cake, and compressed air is periodically blown to clean the powder cake, and the powder collected from the bag dust collector is the carbonized fine powder material, which is introduced into the carbonized material finished product place.

13. The method for low pressure suspension carbonation modification combined emission reduction of industrial flue gas CO2 with powdery materials according to claim 10, characterized in that: In the suspended carbonization process, an ultrasonic vibration is additionally arranged at the bottom of the suspended carbonization bed.

14. The method for low pressure suspension carbonation modification combined emission reduction of industrial flue gas CO2 with powdery materials according to claim 10, characterized in that: In the carbonization aid aqueous solution, the carbonization aid is one or a combination of any two of lignin sulfonate, polycyclic aromatic salt, water-soluble resin sulfonate and alcohol amine organic matter.

15. The method for low pressure suspension carbonation modification combined emission reduction of industrial flue gas CO2 with powdery materials according to claim 10, characterized in that: The powder material is one or a combination of several of cement clinker, alumina clinker, magnesia clinker, spodumene sintered material, steel slag, slag and recycled concrete aggregate.

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