A system for preparing ecological active soil by quick fluidization calcination of humus soil

Abstract

The application discloses a system for preparing ecological active soil by rapidly fluidizing and calcining humus soil, which comprises the following steps: enriching clay minerals in humus soil through a screening pretreatment unit, drying mud cakes through a drying system, crushing, burning and preheating the mud cakes through a fluidized bed preheating unit, grading coarse and fine particles in the humus soil through a particle classifier, rapidly calcining the fine particles in a rapid fluidized bed calcining unit, and converting the fine particles into ecological active soil with auxiliary gelling properties. Finally, waste heat is effectively recovered through a heat exchange system, and the energy utilization efficiency of the whole process is improved. The system and method fully utilize the calorific value of the humus soil, the prepared ecological active soil has high activity and low carbon content, and efficient and sustainable utilization of the humus soil resources can be realized.

Description

Technical Field

[0001] This application belongs to the field of landfill humus resource utilization technology, specifically a system for rapidly fluidizing and calcining humus to prepare eco-active soil. Background Technology

[0002] Old landfills pose a pollution risk to the surrounding atmosphere, soil, and water bodies. With increasingly stringent industry standards for landfills, a significant number of landfills urgently need remediation. The most thorough approach to treating old landfills is excavation and screening to separate sand, gravel, lightweight materials, and humus. Sand and gravel can be used for backfilling, while lightweight materials can be incinerated for power generation; both have relatively mature processing methods. However, humus often contains high concentrations of heavy metals (such as lead, zinc, and mercury) and may also contain organic pollutants and pathogens, posing a potential threat to the environment and human health. Its resource utilization faces significant challenges. How to achieve large-scale resource utilization of humus has become a pressing technical problem that needs to be solved.

[0003] In the cement industry's pursuit of energy conservation, emission reduction, and environmentally friendly development, replacing clinker with auxiliary cementitious materials has become one of the three recognized low-carbon technological approaches. This method, by introducing low-carbon-emission blends (such as blast furnace slag, fly ash, natural volcanic ash, and limestone powder), not only effectively reduces CO2 emissions but also improves the final performance of cement. However, due to limitations in material quality and availability, clinker substitution technology faces challenges such as insufficient substitution volume or a significant decrease in cement strength after substitution, hindering the further promotion of low-carbon cement.

[0004] Humus contains a significant amount of clay minerals. After treatment to enhance its activity, it has the potential to replace a larger proportion of clinker, significantly reducing carbon emissions per unit of concrete building materials. However, how to treat humus to achieve clinker replacement remains a problem to be solved. Furthermore, landfills have large stockpiles of humus, which continue to grow substantially each year. Therefore, improving humus treatment efficiency to address the problem of large-scale humus accumulation in landfills and efficiently utilizing landfill humus for clinker replacement is of great significance. Utility Model Content

[0005] This application addresses the problem that humus soil from landfills contains harmful substances such as heavy metals, organic pollutants, and pathogens, making it difficult to utilize on a large scale. It proposes a rapid fluidized bed calcination system and method for humus soil to prepare eco-active soil with auxiliary gelation properties. This system features low energy consumption, a short calcination cycle, and high activity of the eco-active soil, making it suitable for large-scale resource utilization of humus soil.

[0006] To achieve the above objectives, this application adopts the following technical solution:

[0007] A system for preparing eco-active soil by rapid fluidized bed calcination of humus includes a screening pretreatment unit, a drying unit, a fluidized bed preheating unit, and a rapid fluidized bed calcination unit connected in sequence.

[0008] The screening pretreatment unit is used to wash the humus soil with water to form mud slurry, then settle the mud slurry and filter it to form mud cake.

[0009] The drying unit is used to dry the humus soil from the screening and pretreatment unit;

[0010] The fluidized bed preheating unit includes a fluidized bed preheating reactor, in which humus from the drying unit is preheated to 400℃-600℃ and crushed.

[0011] The rapid fluidized bed calcination unit includes a rapid fluidized bed calcination reactor, which calcines the humus from the fluidized bed preheating unit at 750℃-1000℃ and completes activation in 1-5s to form the ecologically active soil.

[0012] In some preferred embodiments, the screening pretreatment unit includes a feeding device, a water washing screening device, a thickening tank, and a filter press connected in sequence.

[0013] The feeding device feeds the humus into the washing and screening device; the washing and screening device performs hydraulic washing on the humus; the thickening tank is used to settle the slurry formed by hydraulic washing of the humus; the filter press is used to filter the slurry to form a mud cake.

[0014] In some preferred embodiments, the drying unit includes a primary dryer, a secondary dryer, and a hot air furnace I;

[0015] One end of the primary dryer is connected to the filter press, and the other end is connected to one end of the secondary dryer; the other end of the secondary dryer is connected to the fluidized bed preheating reactor; the heat of the primary dryer comes from the secondary dryer; the heat of the secondary dryer comes from the hot air furnace I.

[0016] In some preferred embodiments, the fluidized bed preheating unit further includes a particle classifier and a hot air furnace II;

[0017] One end of the particle classifier is connected to the fluidized bed preheating reactor, and the other end of the particle classifier is connected to the rapid fluidized bed calcination reactor; the particle classifier is used to classify the crushed humus into particles; the heat of the fluidized bed preheating reactor comes from the hot blast furnace II.

[0018] In some preferred embodiments, the fluidized bed preheating reactor is equipped with a rotating stirring component inside;

[0019] The rotary mixing component rotates and mixes the humus from the drying unit to cause collisions, shearing, and crushing.

[0020] In some preferred embodiments, the rapid fluidized bed calcination unit further includes a hot blast stove III, a heat exchange cooler, a cyclone dust collector, a dust collector bag I, and an induced draft fan;

[0021] The hot blast furnace III is connected to the rapid fluidized bed calcining reactor; the rapid fluidized bed calcining reactor is also connected in sequence to the heat exchange cooler, cyclone dust collector, dust collector bag I, and induced draft fan; the heat of the rapid fluidized bed calcining reactor comes from the hot blast furnace III;

[0022] Part of the heat from the hot blast stove I, the hot blast stove II, and the hot blast stove III comes from the heat exchange cooler.

[0023] In some preferred embodiments, the rapid fluidized bed calcination unit further includes a humidifier;

[0024] The gas outlet of the humidifier is connected to the material inlet of the cyclone dust collector; the humidifier uses ultrasonic atomization to generate particles or heating and evaporation to generate water vapor which enters the cyclone dust collector for humidification.

[0025] In addition, this application also provides a system for preparing eco-active soil by rapid fluidized bed calcination of humus, comprising a screening pretreatment unit, a drying unit, a fluidized bed preheating unit, and a rapid fluidized bed calcination unit connected in sequence:

[0026] The drying unit includes a primary dryer, a secondary dryer, and a hot air furnace I; the primary dryer and the secondary dryer are connected in series, and the heat of the primary dryer comes from the secondary dryer; the heat of the secondary dryer comes from the hot air furnace I.

[0027] The fluidized bed preheating unit includes a fluidized bed preheating reactor, a particle classifier, and a hot air furnace II; the particle classifier is used to classify the crushed humus into particles; the heat of the fluidized bed preheating reactor comes from the hot air furnace II.

[0028] The rapid fluidized bed calcination unit includes a rapid fluidized bed calcination reactor, a hot blast furnace III, a heat exchange cooler, a cyclone dust collector, a dust collector bag I, and an induced draft fan; the heat of the rapid fluidized bed calcination reactor comes from the hot blast furnace III; a portion of the heat from the hot blast furnace I, the hot blast furnace II, and the hot blast furnace III comes from the heat exchange cooler.

[0029] Compared with the prior art, this application has the following advantages:

[0030] The activity index of the ecological activated soil prepared in this application is above 99%;

[0031] This application first uses a water washing and screening method to enrich clay minerals in humus by controlling the aperture of the hydraulic screen; the clay minerals such as kaolin contained in the humus undergo a dehydroxylation reaction at high temperature, and their crystal form changes, thus preparing an eco-active soil with auxiliary cementing properties.

[0032] During the removal of hydroxyl groups, water vapor volatilization leaves behind a porous structure. If the calcination time is too long, the porous structure is prone to sintering, which reduces the contact area between the resulting eco-activated soil and water and alkali when activated by alkali, thus reducing its activity. If the calcination time is too short, it cannot be fully activated. Therefore, this application adopts a rapid calcination method. On the one hand, the humus soil is fully preheated to reduce the time required for calcination to reach the reaction temperature, so that the internal and external temperatures of the humus soil are close to the reaction temperature. On the other hand, the particle size of the material entering the rapid fluidized bed calcination reactor is controlled. By reducing the particle size, the temperature at the center of the material quickly reaches the reaction temperature, ensuring that the reaction is completed quickly. Through the above method, eco-activated soil with high activity is obtained.

[0033] The system provided in this application has reasonably optimized the process of humus treatment, enabling efficient coordination of each step in the process of calcining humus to prepare eco-active soil for resource utilization. This can improve the treatment efficiency of humus and the preparation efficiency of eco-active soil. The system has good application prospects in solving the problem of humus accumulation in landfills.

[0034] This application's method utilizes fluidized bed preheating and efficient soil crushing to ensure that fine particles enter the rapid fluidized bed calcination reactor for calcination and activation. This approach ensures complete combustion of combustibles in the humus soil, fully utilizing its calorific value. Furthermore, it allows the core temperature of the humus soil to quickly reach the preheating temperature, achieving thorough preheating and rapid calcination. This effectively avoids the problems of "under-burning" and "over-burning" during humus soil calcination. The resulting eco-activated soil exhibits high activity and low carbon content, making it a suitable substitute for cement and thus reducing energy consumption and carbon dioxide emissions in the building materials industry. Attached Figure Description

[0035] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of the application and, together with their description, serve to explain the application, but do not constitute an undue limitation of the application. In the drawings:

[0036] Figure 1 This is a schematic diagram of the system framework of this application;

[0037] Figure 2This is a schematic diagram of the method flow of this application. Detailed Implementation

[0038] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0039] In the description of this application, it should be understood that the relationship between the method steps can be sequential or non-sequential, as long as it does not affect the overall technical effect, and therefore should not be construed as a limitation of this application. The following description of this application is merely a description of individual embodiments of the technical solution of this application; other embodiments are not shown in the following description, but this does not mean that this application excludes these other embodiments, nor is the technical solution of this application limited to the specific implementations described below, and the scope of protection of this application is not limited to the specific implementations described below. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0040] It should be noted that if the terms "first," "second," etc., appear in the specification, claims, and accompanying drawings of this application, such descriptions are only used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0041] In some embodiments, such as Figure 1 As shown, a system 1 for preparing eco-active soil by rapid fluidized bed calcination of humus soil includes a screening pretreatment unit, a drying unit, a fluidized bed preheating unit, and a rapid fluidized bed calcination unit connected in sequence.

[0042] The screening pretreatment unit is used to wash humus soil to form slurry, then settle the slurry and press the slurry to form a mud cake. The screening pretreatment unit includes a feeding device 111, a washing screening device 112, a thickening tank 113, and a filter press 114 connected in sequence. The feeding device 111 feeds humus soil into the washing screening device 112. The washing screening device 112 hydraulically washes the humus soil. The thickening tank 113 is used to settle the slurry formed by hydraulically washing the humus soil. The filter press 114 is used to press the slurry to form a mud cake. Preferably, the washing screening device 112 has an outlet below the screen for discharging slurry and an outlet on its screen for outputting large-particle plastics and sand obtained from screening.

[0043] The drying unit is used to dry the humus soil from the screening and pretreatment unit. The drying unit includes a primary dryer 121, a secondary dryer 122, and a hot air furnace I 123. One end of the primary dryer 121 is connected to the filter press 114, and the other end is connected to one end of the secondary dryer 122. The other end of the secondary dryer 122 is connected to the fluidized bed preheating reactor 131. The heat for the primary dryer 121 comes from the secondary dryer 122, and the heat for the secondary dryer 122 comes from the hot air furnace I 123. The primary dryer 121 utilizes the residual heat from the secondary dryer 122, ensuring that the heat from the hot air furnace I 123 is fully utilized, thus reducing the processing cost of the humus soil. Preferably, the primary dryer 121 can be a rotary drum dryer, and the secondary dryer 122 can be a belt dryer. During the drying process in the drum dryer, the mud cake continuously tumbles as the drum rotates, making full contact with the hot airflow from the secondary dryer 122, improving drying efficiency and removing most of the moisture from the mud cake. Furthermore, this process also allows the initially dried mud cake to be partially broken up and moved forward. Subsequently, during the drying process in the belt dryer, the initially dried mud cake is smoothly dragged by a transmission device, reducing the frequency of material tumbling, lowering dust generation, and further reducing the moisture content.

[0044] Preferably, the drying unit further includes a dust collector bag II 124 connected to the primary dryer 121 for dust removal of the flue gas generated during the drying process from the primary dryer 121.

[0045] The fluidized bed preheating unit includes a fluidized bed preheating reactor 131, in which humus from the drying unit is preheated to 400℃-600℃ and crushed. The fluidized bed preheating unit also includes a particle classifier 132 and a hot air furnace II 133. One end of the particle classifier 132 is connected to the fluidized bed preheating reactor 131, and the other end of the particle classifier 132 is connected to the rapid fluidized bed calcination reactor 141. The particle classifier 132 is used to classify the crushed humus into particles. The heat of the fluidized bed preheating reactor 131 comes from the hot air furnace II 133. The particle classifier 132 is used to classify the coarse and fine particles in the crushed humus. The coarse particles are returned to the fluidized bed preheating reactor 131 for crushing, and the fine particles enter the rapid fluidized bed calcination unit. Specifically, the solid outlet of the secondary dryer 122 is connected to the solid inlet of the fluidized bed preheating reactor 131, the outlet of the fluidized bed preheating reactor 131 is connected to the inlet of the particle classifier 132, the coarse particle outlet of the particle classifier 132 is connected to the fluidized bed preheating reactor 131, and the coarse particles enter the fluidized bed preheating reactor 131 from the particle classifier 132 for further preheating and crushing; the fine particle outlet of the particle classifier is connected to the rapid fluidized bed calcining reactor 141, and the fine particles enter the rapid fluidized bed calcining reactor 141 for activation.

[0046] Preferably, the particle classifier 132 includes, but is not limited to, an air classifier; in the particle classifier 132, the humus obtained after drying in the secondary dryer 122 moves at high speed from the particle classifier to the classification zone with the rising airflow. Under the strong centrifugal force generated by the high-speed rotating classification turbine, coarse and fine particles are effectively separated. The fine particles enter the rapid fluidized bed calcination reactor 141 through the gap between the classification wheel blades, while the coarse particles descend along the cylinder wall and are transported again to the fluidized bed preheating reactor 131 for further crushing and preheating.

[0047] Preferably, the fluidized bed preheating reactor 131 is equipped with a rotating stirring component (not shown in the figure). The rotating stirring component rotates and stirs the humus soil from the drying unit to cause collision, shearing and crushing, transforming it into fine particles. Due to their small size, the fine particles can quickly reach the preheating temperature at their center, achieving sufficient preheating. After preheating, the organic matter inside is more easily completely burned, thereby reducing the carbon content and generating calorific value. The generated calorific value can be fully utilized, reducing the energy consumption of humus soil treatment. The organic matter inside the fine particles is more easily completely burned, making full use of the calorific value of the humus soil and reducing the carbon content of the product. Carbon has a porous structure and a large specific surface area, which will adsorb a large amount of mixing water and admixtures such as water-reducing agents. It is necessary to significantly increase the water consumption to ensure the initial slump. This not only changes the water-cement ratio, but also causes the concrete to lose slump too quickly during transportation and construction when using eco-active soil with high carbon content, making it difficult to vibrate and compact the concrete, affecting the construction quality. The bonding force between carbon and cement stone is weak, forming a weak interface, which is prone to becoming a crack source under stress. Meanwhile, carbon occupies a certain amount of space in concrete, thereby reducing the effective bonding area between cement paste and aggregates, and lowering the overall strength of the concrete. Furthermore, the porous structure of carbon and the weak interface between carbon and cement paste increase the connectivity of pores within the concrete, creating channels for moisture and harmful media to penetrate. Under the influence of water or corrosive solutions, harmful substances can more easily penetrate into the concrete, accelerating the deterioration of its performance.

[0048] The rapid fluidized bed calcination unit includes a rapid fluidized bed calcination reactor 141, which calcines the humus from the fluidized bed preheating unit at 750℃-1000℃ and completes activation in 1-5s to form the ecologically active soil. The rapid fluidized bed calcination unit further includes a hot blast furnace III 147, a heat exchange cooler 142, a cyclone dust collector 143, a dust collector bag I 144, and an induced draft fan 145; the hot blast furnace III 147 is connected to the rapid fluidized bed calcination reactor 141; the rapid fluidized bed calcination reactor 141 is also sequentially connected to the heat exchange cooler 142, the cyclone dust collector 143, the dust collector bag I 144, and the induced draft fan 145; the heat of the rapid fluidized bed calcination reactor 141 comes from the hot blast furnace III 147; the humus is calcined at 750℃-1000℃ and undergoes a complete decrystalline transformation in 1-5 seconds, quickly leaving the rapid fluidized bed calcination reactor to prevent over-burning; the cyclone dust collector is used for gas-solid separation, specifically for separating the ecological activated soil and flue gas; the flue gas enters the dust collector bag I 144 for dust removal and is then discharged to the exhaust device 146 by the induced draft fan 145.

[0049] Part of the heat from the hot blast furnace I 123, the hot blast furnace II 133, and the hot blast furnace III 147 comes from the heat exchange cooler 142.

[0050] Preferably, the rapid fluidized bed calcination reactor 141 can be a tubular reactor or a conveying bed; the temperature inside the rapid fluidized bed calcination reactor 141 is raised to the required reaction temperature by the hot blast furnace III 147, and the airflow speed can be adjusted so that the humus can quickly pass through the reactor at this reaction temperature and be transformed into a dehydration and crystal transformation process in a very short time.

[0051] Preferably, the rapid fluidized bed calcination unit further includes a humidifier 148; the gas outlet of the humidifier 148 is connected to the material inlet of the cyclone dust collector 143; the humidifier 148 uses ultrasonic atomization to form particles or heating and evaporation to generate water vapor which enters the cyclone dust collector 143 for humidification, thereby increasing the humidity of the flue gas. Materials with a particle size of less than 2 μm agglomerate, ultimately increasing the ability of the cyclone dust collector to capture fine materials (cyclone dust collectors have difficulty capturing materials with a particle size of less than 2 μm, and many clay minerals in humus soil have a particle size of less than 2 μm). By increasing humidity, fine particles agglomerate, thereby capturing them; after being treated by the cyclone dust collector, the flue gas is thoroughly dusted by the dust collector bag I before being discharged, which can effectively reduce air pollution.

[0052] Preferably, the rapid fluidized bed calcination reactor 141 includes, but is not limited to, a tubular reactor or a conveying bed.

[0053] Preferably, the heat exchange cooler 142 is either a tubular heat exchanger or a plate heat exchanger; the heat exchange cooler separates the hot and cold fluids through a solid partition (such as a metal tube wall), and heat is transferred from the hot fluid to the cold fluid through the partition, thereby realizing heat exchange. The hot air generated in this process is transported to hot blast furnace I 123, hot blast furnace II 133 and hot blast furnace III 147 for energy supply.

[0054] Preferably, the rapid fluidized bed calcination unit further includes an exhaust device 146, which includes, but is not limited to, a chimney, and is connected to an induced draft fan 145.

[0055] Preferably, the dust collector bag I 144 and the dust collector bag II 124 can be the same. When the dust collector bag I 144 and the dust collector bag II 124 are the same, the primary dryer 121 and the cyclone dust collector 143 are simultaneously connected to the dust collector bag.

[0056] After activation, the activity index of the resulting ecologically active soil is above 99%.

[0057] In some embodiments, this application also provides a system 1 for preparing eco-active soil by rapid fluidized bed calcination of humus, comprising a screening pretreatment unit, a drying unit, a fluidized bed preheating unit, and a rapid fluidized bed calcination unit connected in sequence:

[0058] The drying unit includes a primary dryer 121, a secondary dryer 122, and a hot air furnace I 123; the primary dryer 121 and the secondary dryer 122 are connected in series, and the heat of the primary dryer 121 comes from the secondary dryer 122; the heat of the secondary dryer 122 comes from the hot air furnace I 123.

[0059] The fluidized bed preheating unit includes a fluidized bed preheating reactor 131, a particle classifier 132, and a hot air furnace II 133; the particle classifier 132 is used to classify the crushed humus into particles; the heat of the fluidized bed preheating reactor 131 comes from the hot air furnace II.

[0060] The rapid fluidized bed calcination unit includes a rapid fluidized bed calcination reactor 141, a hot blast furnace III 147, a heat exchange cooler 142, a cyclone dust collector 143, a dust collector bag I 144, and an induced draft fan 145; the heat of the rapid fluidized bed calcination reactor 141 comes from the hot blast furnace III 147; a portion of the heat from the hot blast furnace I 123, the hot blast furnace II 133, and the hot blast furnace III 147 comes from the heat exchange cooler 142.

[0061] In addition, this application also provides a method for preparing eco-active soil by rapid fluidized bed calcination of humus, such as... Figure 2 The above includes:

[0062] S1: After washing the humus soil with water to form mud, it is allowed to settle and then the mud is pressed and filtered to form mud cake.

[0063] S2: Dry the mud cake to obtain dry humus;

[0064] S3: Preheat the dried humus to 400℃-600℃ and then crush it; and

[0065] S4: The crushed humus soil is calcined at 750℃-1000℃ and activated in 1-5 seconds to form the ecologically active soil.

[0066] Preferably, the crushing includes particle grading; calcining humus with a particle size less than 0.3 mm at 750℃-1000℃ and activating it in 1-5 seconds to form the ecologically active soil, and further crushing humus with a particle size greater than 0.3 mm.

[0067] Preferably, the hydraulic rinsing is carried out using a water washing and screening device, which includes a screen with an aperture of 0.05 mm to 2 mm. After hydraulic rinsing, the humus is filtered through the screen, while lightweight materials, as well as larger particles such as sand, gravel, and plastic, remain on the screen. Smaller clay minerals pass through the screen to form slurry.

[0068] Preferably, the mud enters a thickening tank, where flocculants are added. The flocculants accelerate the sedimentation of the mud, thereby concentrating it. The concentrated mud has a water content of 60%-90%.

[0069] Preferably, the moisture content of the filter cake after pressing is 30%-40%.

[0070] Preferably, the drying process involves sequential primary drying and secondary drying; the temperature of the secondary drying is 100℃-300℃.

[0071] Preferably, the moisture content of the dried mud cake is 3%-10%.

[0072] Preferably, the flow rate of dry humus in the fluidized bed preheating reactor is 1 m / s - 5 m / s.

[0073] Preferably, the fine particles have a particle size of less than 0.3 mm, and the coarse particles have a particle size of more than 0.3 mm.

[0074] Preferably, the airflow velocity of the hot gas is 10 m / s - 20 m / s.

[0075] Preferably, the cooling medium is air. The temperature of the ecological activated soil decreases after being mixed with the medium for heat exchange. The air is then heated and used to supply energy for hot blast stove I, hot blast stove II, and hot blast stove III.

[0076] The eco-active soil obtained in this application has an activity index of over 99%. A high activity index is beneficial for providing higher strength during application and can better replace cement clinker.

[0077] This application also provides specific embodiments and comparative examples as follows:

[0078] Example 1

[0079] A method for preparing eco-activated soil:

[0080] (1) Humus enters the washing and screening device through the feeding device. The screen size of the washing and screening device is 0.05mm. The humus is hydraulically washed to obtain mud with a particle size <0.05mm. After the mud is settled in the thickening tank containing flocculant, it is then filtered through the filter press system to obtain mud cake with a moisture content of 35%.

[0081] (2) The mud cake enters the first-stage drum dryer and the second-stage belt dryer in sequence. After being dried by hot air from the hot air furnace I at 300°C, most of the moisture is removed, and it becomes dry humus with a moisture content of 10%. The flue gas in the first-stage drum dryer enters the dust collector bag II for dust removal and then enters the induced draft fan 1, and is then discharged through the chimney.

[0082] (3) The dried humus enters the fluidized bed preheating reactor. After being heated by hot air from hot blast furnace II at 600°C, the organic matter and other substances are burned. At the same time, the humus is preheated to 600°C. The preheated humus enters the particle classifier. The coarse particles with a particle size > 0.15 mm are returned to the fluidized bed preheating reactor through the return device to continue to be crushed and burned. The fine particles with a particle size < 0.15 mm and the gas enter the rapid fluidized bed calcination reactor.

[0083] (4) Fine particles with a particle size of <0.15mm and gas enter the rapid fluidized bed calcination reactor and are rapidly calcined for 1s under hot air from hot blast furnace III at 1000℃ to generate ecological activated soil. The ecological activated soil is cooled to 250℃ in a heat exchange cooler, where the heat exchange medium is air. The heat exchange medium is then passed into hot blast furnace I, hot blast furnace II and hot blast furnace III for reuse. The cooled ecological activated soil is then collected after the flue gas is separated in a cyclone dust collector. The separated flue gas enters dust collector bag I for dust removal and is then discharged.

[0084] Example 2

[0085] This embodiment provides a method for preparing ecologically active soil by fluidizing humus:

[0086] (1) Humus enters the water washing and screening device through the feeding device. The humus is hydraulically washed with a 0.05mm screen to obtain mud with a particle size <0.05mm. After sedimentation in the thickening tank, the mud is then filtered through the filter press system to obtain mud cake with a moisture content of 35%.

[0087] (2) The mud cake enters the first-stage drum dryer and the second-stage belt dryer in sequence. After being dried by hot air at 300°C from hot air furnace I, most of the moisture is removed, and it becomes dry humus with a moisture content of 5%. The flue gas in the first-stage drum dryer enters the dust collector bag II for dust removal and then enters the induced draft fan 1, and is then discharged through the chimney.

[0088] (3) The dried humus enters the fluidized bed preheating reactor. After being heated by hot air from hot blast furnace II at 600°C, the organic matter is burned, and the resulting humus is preheated to 600°C. The preheated humus enters the particle classifier. The coarse particles with a particle size > 0.3 mm are returned to the fluidized bed preheating reactor through the return device to continue to be crushed and burned. The fine particles with a particle size < 0.3 mm and the gas enter the rapid fluidized bed calcination reactor.

[0089] (4) The preheated fine particles with a particle size of <0.15mm and the gas enter the rapid fluidized bed calcination reactor and are rapidly calcined for 4s under hot gas at 900℃ from hot blast furnace III to obtain ecological activated soil. The above ecological activated soil is cooled to 250℃ in a heat exchange cooler, where the heat exchange medium is air. The heat exchange medium is then passed into hot blast furnace I, hot blast furnace II and hot blast furnace III for reuse. The gas with a water content of 10% (volume) from the humidifier enters the cyclone dust collector at a speed of 5m / s to increase the humidity. The ecological activated soil is collected after the flue gas is separated in the cyclone dust collector. The separated flue gas enters the dust collector bag I for dust removal and is then discharged.

[0090] Example 3

[0091] This embodiment provides a method for preparing eco-active soil by fluidizing humus soil, and the production steps are as follows:

[0092] (1) Humus enters the water washing and screening device through the feeding device. The humus is hydraulically washed with a 0.05mm screen to obtain mud with a particle size <0.05mm. After sedimentation in the thickening tank, the mud is then filtered through the filter press system to obtain mud cake with a moisture content of 35%.

[0093] (2) The mud cake enters the first-stage drum dryer and the second-stage belt dryer in sequence. After being dried by hot air from the hot air furnace I at 300°C, most of the moisture is removed, and it becomes dry humus with a moisture content of 5%. The hot air enters the first-stage drum dryer from the second-stage belt dryer. The flue gas in the first-stage drum dryer enters the dust collector bag II for dust removal and then enters the induced draft fan 1, and is then discharged through the chimney.

[0094] (3) The dried humus enters the fluidized bed preheating reactor. After being heated by hot air from hot blast furnace II at 600°C, the organic matter and other substances are burned. At the same time, the humus is preheated to 600°C. The preheated humus enters the particle classifier. The coarse particles with a particle size > 0.15 mm are returned to the fluidized bed preheating reactor through the return device to continue to be crushed and burned. The fine particles with a particle size < 0.15 mm and the gas enter the rapid fluidized bed calcination reactor.

[0095] (4) The preheated fine particles with a particle size of <0.15mm and the gas enter the rapid fluidized bed calcination reactor and are rapidly calcined for 5s under hot gas from hot blast furnace III at 750℃ to obtain ecological activated soil. The above ecological activated soil is cooled to 250℃ in a heat exchange cooler, where the heat exchange medium is air. The heat exchange medium is then passed into hot blast furnace I, hot blast furnace II and hot blast furnace III for reuse. The gas with a water content of 10% (volume) from the humidifier enters the cyclone dust collector at a speed of 5m / s. The ecological activated soil is collected after the flue gas is separated in the cyclone dust collector. The separated flue gas enters the dust collector bag I for dust removal and is then discharged.

[0096] Comparative Example 1

[0097] This embodiment provides a method for preparing eco-active soil by fluidizing humus soil, and the production steps are as follows:

[0098] (1) Humus enters the water washing and screening device through the feeding device. The humus is hydraulically washed with a 0.05mm mesh screen to obtain mud with a particle size <0.05mm. After the mud is settled in the thickening tank, it is then filtered by the filter press to obtain mud cake with a moisture content of 35%.

[0099] (2) The mud cake enters the first-stage drum dryer and the second-stage drum dryer in sequence. After being dried by hot air from hot air furnace I at 300°C, most of the moisture is removed, and it becomes dry humus soil with a moisture content of 10%.

[0100] (3) After placing the dried material into a muffle furnace and calcining and activating it at a suitable temperature (850℃, 120min), it is taken out to obtain ecological activated soil.

[0101] Performance testing

[0102] The performance tests of the eco-active soil in the examples and comparative examples are shown in Table 1 below. The loss on ignition of the eco-active soil was measured in accordance with the GB / T176-2017 standard.

[0103] The ecological activated soil was tested for residue on a 45µm sieve and its activity index according to GB / T 51003-2014 standard.

[0104] The method for testing the carbon content of eco-activated soil is as follows: After grinding and weighing the sample, place it in a thermogravimetric instrument. First, heat it to 950℃ in a nitrogen atmosphere and keep it at that temperature for 60 minutes until constant weight is achieved, so that water and decomposable inorganic salts can be fully released from the sample. Then, cool it to room temperature, switch the nitrogen atmosphere to an oxygen atmosphere, heat it to 950℃, and keep it at that temperature for 60 minutes to allow the carbon to burn completely. The carbon content in the eco-activated soil is determined by the maximum weight loss in the oxidizing atmosphere.

[0105] Table 1

[0106]

[0107] As can be seen from the table above, the system provided in this application has a short processing time and high processing efficiency for humus, making it suitable for large-scale humus treatment and effectively solving the existing problem of humus accumulation. Furthermore, it can be seen that the method provided in this application can produce highly active ecological soil with an activity index reaching 101.2 and a low carbon content of 0.2%, showing promising application prospects in cement clinker substitution.

[0108] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims. The selected and described embodiments are intended to best elucidate the principles of this application and its practical application, thereby enabling other those skilled in the art to best utilize this application with various modifications suitable for the contemplated specific purpose, as well as the various described embodiments.

Claims

1. A system for rapidly fluidizing and calcining humus to prepare eco-active soil, characterized in that, It includes a screening pretreatment unit, a drying unit, a fluidized bed preheating unit, and a rapid fluidized bed calcination unit connected in sequence: The screening pretreatment unit is used to wash the humus soil with water to form mud slurry, then settle the mud slurry and filter it to form mud cake. The drying unit is used to dry the humus soil from the screening and pretreatment unit; The fluidized bed preheating unit includes a fluidized bed preheating reactor, in which humus from the drying unit is preheated to 400℃-600℃ and crushed. The rapid fluidized bed calcination unit includes a rapid fluidized bed calcination reactor, which calcines the humus from the fluidized bed preheating unit at 750℃-1000℃ and completes activation in 1-5s to form the ecologically active soil.

2. The system for preparing eco-active soil by rapid fluidized bed calcination of humus according to claim 1, characterized in that: The screening pretreatment unit includes a feeding device, a water washing screening device, a thickening tank, and a filter press connected in sequence. The feeding device sends the humus into the water washing and screening device. The water washing and screening device performs hydraulic washing of the humus; the thickening tank is used to settle the slurry formed by hydraulic washing of the humus; and the filter press is used to filter the slurry to form a mud cake.

3. The system for preparing eco-active soil by rapid fluidized bed calcination of humus according to claim 2, characterized in that: The drying unit includes a primary dryer, a secondary dryer, and a hot air furnace I; One end of the primary dryer is connected to the filter press, and the other end is connected to one end of the secondary dryer; the other end of the secondary dryer is connected to the fluidized bed preheating reactor; the heat of the primary dryer comes from the secondary dryer. The heat for the secondary dryer comes from hot air furnace I.

4. The system for preparing eco-active soil by rapid fluidized bed calcination of humus according to claim 3, characterized in that: The fluidized bed preheating unit also includes a particle classifier and a hot air furnace II; One end of the particle classifier is connected to the fluidized bed preheating reactor, and the other end of the particle classifier is connected to the rapid fluidized bed calcination reactor; the particle classifier is used to classify the crushed humus into particles; the heat of the fluidized bed preheating reactor comes from the hot blast furnace II.

5. The system for preparing eco-active soil by rapid fluidized bed calcination of humus according to claim 4, characterized in that: The fluidized bed preheating reactor is equipped with a rotating stirring component inside; The rotary mixing component rotates and mixes the humus from the drying unit to cause collisions, shearing, and crushing.

6. The system for preparing eco-active soil by rapid fluidized bed calcination of humus according to claim 5, characterized in that: The rapid fluidized bed calcination unit also includes a hot blast stove III, a heat exchange cooler, a cyclone dust collector, a dust collector bag I, and an induced draft fan; The hot blast furnace III is connected to the rapid fluidized bed calcining reactor; the rapid fluidized bed calcining reactor is also connected in sequence to the heat exchange cooler, cyclone dust collector, dust collector bag I, and induced draft fan; the heat of the rapid fluidized bed calcining reactor comes from the hot blast furnace III; Part of the heat from the hot blast stove I, the hot blast stove II, and the hot blast stove III comes from the heat exchange cooler.

7. The system for preparing eco-active soil by rapid fluidized bed calcination of humus according to claim 6, characterized in that: The rapid fluidized bed calcination unit also includes a humidifier; The gas outlet of the humidifier is connected to the material inlet of the cyclone dust collector; the humidifier uses ultrasonic atomization to generate particles or heating and evaporation to generate water vapor which enters the cyclone dust collector for humidification.

8. A system for rapidly fluidizing and calcining humus to prepare eco-active soil, characterized in that, It includes a screening pretreatment unit, a drying unit, a fluidized bed preheating unit, and a rapid fluidized bed calcination unit connected in sequence: The drying unit includes a primary dryer, a secondary dryer, and a hot air furnace I; the primary dryer and the secondary dryer are connected in series, and the heat of the primary dryer comes from the secondary dryer; the heat of the secondary dryer comes from the hot air furnace I. The fluidized bed preheating unit includes a fluidized bed preheating reactor, a particle classifier, and a hot air furnace II; the particle classifier is used to classify the crushed humus into particles; the heat of the fluidized bed preheating reactor comes from the hot air furnace II. The rapid fluidized bed calcination unit includes a rapid fluidized bed calcination reactor, a hot blast furnace III, a heat exchange cooler, a cyclone dust collector, a dust collector bag I, and an induced draft fan; the heat of the rapid fluidized bed calcination reactor comes from the hot blast furnace III; a portion of the heat from the hot blast furnace I, the hot blast furnace II, and the hot blast furnace III comes from the heat exchange cooler.

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