System for the total utilization of humus soil

Abstract

The application discloses a system for utilizing all components of humus soil, which comprises the following steps: performing hydraulic screening, drying and calcination treatment on humus soil to obtain ecological active soil, and the 28d activity index of the ecological active soil is above 85%. Through efficient heat transfer in the system, mutual influence and mutual restriction between parameters, a synergistic coupling whole is formed, and a full-component quality enrichment utilization-uniform rapid heat activation system is constructed. The material flow and energy flow of the whole process system are highly synergistically coupled, the preparation cost is reduced, and harmless treatment of the humus soil and materialization and energy utilization of all components are realized.

Description

Technical Field

[0001] This application belongs to the technical field of solid waste resource utilization, specifically a system for the complete utilization of humus. Background Technology

[0002] During the remediation of old landfills, the screening and processing of existing municipal solid waste generates a large amount of humus. Shenzhen currently has approximately 16.93 million cubic meters of landfill waste, of which over 8 million cubic meters (approximately 10.4 million tons) contain humus. Humus, as a new type of urban solid waste, is characterized by its complex composition, large volume, and difficulty in treatment. Some areas are already facing landfill capacity shortages and land resource scarcity.

[0003] Traditional methods for treating humus include landfilling, but direct landfilling consumes a large amount of land resources and may pose safety risks, failing to meet the development needs of green cities. How to efficiently utilize humus has become a key issue hindering the remediation of aging landfills.

[0004] Humus is an organic soil composed of the residue from the decomposition of organic matter and inorganic matter leached by leachate from existing waste. Humus has a complex composition, with its main chemical components being SiO2, Al2O3, Fe2O3, and CaO, similar to clay minerals. However, humus contains pollutants such as heavy metals and organic matter, and direct utilization can impact the ecological environment and may cause secondary pollution due to heavy metal ion leakage. Some studies have separated the components of humus, achieving high-value utilization of some components; however, this method, utilizing only a portion of the humus, inevitably leads to resource waste.

[0005] Furthermore, due to the large stock of humus, soil pollution continues to occur. Achieving efficient and large-scale treatment of humus is an urgent problem to be solved in this field. Existing humus treatment systems cannot effectively treat large quantities of humus efficiently, which will also lead to increased treatment costs and ultimately result in poor humus remediation effects. Utility Model Content

[0006] This application addresses the problems of poor resource utilization and inability to process humus on a large scale in existing technologies by proposing a system for the full utilization of humus components, which can achieve harmless treatment of humus and the material and energy utilization of all its components.

[0007] To achieve the above objectives, this application adopts the following technical solution:

[0008] A system for the complete utilization of humus components includes:

[0009] Hydraulic screening unit is used to hydraulically screen humus to obtain slurry.

[0010] A drying unit, connected to the cement screening unit, is used to flocculate and concentrate the slurry after hydraulic screening, then stir, filter, and dry it; and

[0011] The calcination unit, connected to the drying unit, is used to recover the heat generated by the decomposition of organic matter in the humus and to perform calcination thermal activation on the humus, and to provide heat for the drying of the drying unit.

[0012] In some preferred embodiments, the hydraulic screening unit includes a feeding device, a mixing hopper, and a hydraulic screening device connected in sequence;

[0013] The hydraulic screening equipment is a double-layer dewatering vibrating screen; the double-layer dewatering vibrating screen separates coarse sand larger than 2mm, fine sand of 0.15-2mm and mud smaller than 0.15mm.

[0014] In some preferred embodiments, the drying unit includes a settling device, a mixing tank, a filter press, and a dryer connected in sequence; the hydraulic screening device and the mixing silo are both connected to the settling device, and the slurry smaller than 0.15mm after screening by the hydraulic screening device enters the settling device, and the supernatant of the settling device enters the mixing silo.

[0015] In some preferred embodiments, the calcination unit includes a waste heat preheating fluidized bed calcination device;

[0016] The waste heat preheating fluidized bed calcination device includes a preheating chamber and a fluidized bed calcination furnace connected in sequence, wherein the fluidized bed calcination furnace provides heat for the preheating of the preheating chamber.

[0017] In some preferred embodiments, the fluidized bed calciner is connected to the dryer, and the fluidized bed calciner provides heat for the drying process of the dryer.

[0018] Compared with the prior art, this application has the following advantages:

[0019] This application achieves efficient heat transfer within the system and mutual influence and constraint among various parameters, forming a synergistically coupled whole. The material flow and energy flow in the entire process are highly synergistically coupled, which not only reduces the preparation cost but also realizes the harmless treatment of humus and the materialization and energy utilization of all components. It also enables the production process to be continuous, automated, large-scale, and intelligent, with low comprehensive energy consumption per ton of product.

[0020] This application constructs a multi-stage uniform temperature rapid thermal activation system, which promotes the superposition of continuous airflow and discrete humus particles to form a new continuous phase medium, enhances the heat and mass transfer process, makes the temperature uniform and controllable, and while thoroughly decomposing organic pollutants, rapidly removes hydroxyl groups between the kaolinite structural layers of humus, transforming it into highly active ecological active soil, which greatly broadens the application field of humus and increases its added value. Attached Figure Description

[0021] 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:

[0022] Figure 1 This is a schematic diagram of the system framework of this application;

[0023] Figure 2 This is a schematic diagram of the method flow of this application;

[0024] Figure 3 This is a scanning electron microscope image of cement paste prepared according to Example 1 of this application;

[0025] Figure 4 This is a scanning electron microscope image of the cement paste prepared in Comparative Example 1 of this application. Detailed Implementation

[0026] 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.

[0027] 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.

[0028] 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.

[0029] In some embodiments, such as Figure 1 As shown, a system 1 for the complete utilization of humus soil comprises:

[0030] A hydraulic screening unit is used to hydraulically screen humus to obtain slurry; the hydraulic screening unit includes a feeding device 11, a mixing bin 12 and a hydraulic screening device 13 connected in sequence; the hydraulic screening device 13 is a double-layer dewatering vibrating screen; the double-layer dewatering vibrating screen screens out coarse sand larger than 2mm, fine sand of 0.15-2mm and slurry smaller than 0.15mm.

[0031] A drying unit, connected to the cement screening unit, is used to flocculate and concentrate the slurry after hydraulic screening, then stir, filter press, and dry it. The drying unit includes a sedimentation device 14, a mixing tank 15, a filter press 16, and a dryer 17 connected in sequence. The hydraulic screening device 13 and the mixing silo 12 are both connected to the sedimentation device 14. Slurry smaller than 0.15mm after screening by the hydraulic screening device 13 enters the sedimentation device 14, and the supernatant from the sedimentation device 14 enters the mixing silo 12. Preferably, the sedimentation device 14 is a thickening tank containing flocculant, used to initially reduce the water content. Preferably, the dryer 17 is a dryer used for heating and crushing. The dryer 17 is connected to the filter press 16, and the dryer can be a flash dryer or an airflow dryer.

[0032] A calcination unit, connected to the drying unit, is used to recover the heat generated by the decomposition of organic matter in the humus soil and to perform calcination thermal activation on the humus soil, and to provide heat for the drying process of the drying unit. The calcination unit includes a waste heat preheating fluidized bed calcination device; the waste heat preheating fluidized bed calcination device includes a preheating chamber 18 and a fluidized bed calcination furnace 19 connected in sequence, the fluidized bed calcination furnace 19 providing heat for the preheating of the preheating chamber 18. The fluidized bed calcination furnace 19 is connected to the dryer 17, and the fluidized bed calcination furnace 19 provides heat for the drying of the dryer 17. Preferably, the calcination unit further includes an ecological activated soil storage tank 110, which is connected to the fluidized bed calcination furnace 19. The calcination unit may also include a crushing device (not shown in the figure), which can be a ball mill; the crushing device is located between the waste heat preheating fluidized bed calcination device and the ecological activated soil storage tank 110.

[0033] This application constructs a comprehensive solution of "water washing pretreatment + drying + waste heat preheating + fluidized bed thermal activation", which can accurately match the needs of building material raw materials prepared by thermal activation of humus, and realize an efficient and high-quality production process from raw material processing to the transformation of ecological active soil products.

[0034] In some embodiments, such as Figure 2 As shown, this application also provides a method for the complete utilization of humus, comprising:

[0035] S1: Hydraulic screening of humus soil to obtain mud;

[0036] The process of hydraulically screening humus to obtain slurry includes: screening out coarse sand larger than 2 mm, fine sand of 0.15-2 mm, and slurry smaller than 0.15 mm. The slurry smaller than 0.15 mm is then flocculated and concentrated, and the supernatant is used to mix with humus before hydraulic screening.

[0037] S2: After hydraulic screening, the slurry is flocculated, concentrated, stirred, filtered, and dried; and

[0038] S3: The dried humus is calcined and thermally activated to recover the heat generated from the decomposition of organic matter in the humus. The calcination and thermal activation of the dried humus also includes preheating the humus; the heat generated from the calcination and thermal activation, as well as the heat generated from the decomposition of organic matter in the humus, provides the heat for the preheating and drying; the calcination and thermal activation temperature is 700℃-1000℃, and the calcination time is 1s-20s. Excessive or insufficient calcination time will result in low activity of the obtained ecologically activated soil. The method of this application is beneficial for controlling the thermal activation time.

[0039] In some embodiments, this application also provides an ecologically active soil obtained by the method described above, wherein the 28-day activity index of the ecologically active soil is above 85%, the water requirement ratio is 95%-105%, and the particle size D90 is 25μm-50μm.

[0040] This application also provides specific embodiment 1 and comparative example 1 to illustrate the solution and effects of this application.

[0041] Example 1

[0042] Humus and water are mixed in a mixing bin 12 at a mass ratio of 3:1. After mixing, the mixture is conveyed to a double-layer dewatering vibrating screen 13 for hydraulic screening. Coarse sand larger than 2mm is screened out for later use. Humus smaller than 2mm is further screened by the double-layer hydraulic screen, and fine sand of 0.15-2mm is screened out for later use. Slurry smaller than 0.15mm enters the thickening tank.

[0043] After the mud is flocculated and concentrated in the thickening tank, the supernatant is returned and directly enters the water treatment system or enters the mixing bin 12 to be mixed with humus. The concentrated mud is stirred in the mixing tank 15 and then pumped into the filter press 16 for filter pressing to obtain mud cake.

[0044] A portion of the high-temperature flue gas from the fluidized bed calciner 19 enters the bottom of the airflow dryer 17 and is stirred by a stirring paddle. The mud cake enters the airflow dryer 17, is crushed and dispersed under the stirring action, and is dried under the action of high-temperature flue gas. At the same time, the dried humus is graded. Large particles of humus that are not fully dried are retained for further drying and crushing, while small particles of humus are discharged and collected.

[0045] Another portion of the high-temperature flue gas from the fluidized bed calciner 19 enters the preheating chamber 18 to preheat the small-particle humus soil obtained above. Then, it enters the fluidized bed calciner and is calcined at 900°C for 5 seconds to obtain highly active ecological activated soil and high-temperature flue gas. The ecological activated soil is ball-milled and enters the ecological activated soil storage silo 110. The high-temperature flue gas enters the airflow dryer 17 and the preheating chamber 18 for drying and preheating.

[0046] Comparative Example 1

[0047] The humus soil was passed through a double-layer vibrating dry sieve and then calcined at 900℃ for 5 seconds.

[0048] The composition of the humus soil from Example 1 and the resulting eco-active soil was tested, and it was found that the loss on ignition decreased by 10%. The heavy metal leaching content is shown in Table 1. As can be seen from Table 1, the heavy metal leaching content of the eco-active soil obtained in Example 1 meets the requirements for leached heavy metal content in GB / T 2847-2022. The chlorine content in the eco-active soil is 0.055%, and the main components are metakaolinite or active SiO2·Al2O3. The 28-day activity index is 100%, which shows high activity and good application prospects.

[0049] The composition of the humus soil in Comparative Example 1 and the resulting ecologically active soil was tested, and it was found that the loss on ignition was reduced by 10%. Table 1 shows the results of the heavy metal ion content determination, in which nickel and copper both exceeded the standard. The chlorine content in the ecologically active soil was 0.075%, and the main components were quartz and metakaolin. The 28-day activity index was 75%, which is relatively low. Therefore, it cannot provide good strength in building materials.

[0050] Table 1

[0051]

[0052] 42.5 cement, water, and the active soil prepared in Example 1 or Comparative Example 1 were mixed at a mass ratio of 70:8:30 to form a cement paste. The cement paste was cured for 7 days and 28 days, and its condition was observed using a scanning electron microscope. (Specific details are as follows...) Figure 3 (Example 1) and Figure 4 As shown in (Comparative Example 1).

[0053] Example 1 uses hydraulic screening to treat humus soil, from Figure 3 It can be seen that the cement paste prepared from the ecologically activated soil obtained after calcination and thermal activation in Example 1 is relatively dense because the hydraulic screening process can cover the surface of the humic soil particles with a dense layer of hydration products during calcination. Figure 3 It can also be seen that Ca(OH)2 crystals are plate-like. Ca(OH)2 reacts with active SiO2 and Al2O3 to form dense CSH and needle-like ettringite crystals, which play a role in strength.

[0054] Comparative Example 1 uses a dry sieving method, by Figure 4 It can be seen that the cement paste prepared from the calcined eco-active soil obtained in Comparative Example 1 has a loose internal structure, with mostly smooth-surfaced quartz particles inside, which only serve as fillers for micro-aggregates. The large number of quartz particles lack sufficient hydration products to fill them, which increases the porosity and leads to a decrease in the compressive strength of the sample.

[0055] 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 the utility model patent. 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 the complete utilization of humus components, characterized in that, include: Hydraulic screening unit is used to hydraulically screen humus to obtain slurry. The drying unit, connected to the cement screening unit, is used to flocculate and concentrate the slurry after hydraulic screening, then stir, filter, and dry it. as well as The calcination unit, connected to the drying unit, is used to recover the heat generated by the decomposition of organic matter in the humus and to perform calcination thermal activation on the humus, and to provide heat for the drying of the drying unit.

2. The system for the complete utilization of humus soil according to claim 1, characterized in that: The hydraulic screening unit includes a feeding device, a mixing silo, and a hydraulic screening device connected in sequence. The hydraulic screening equipment is a double-layer dewatering vibrating screen; the double-layer dewatering vibrating screen separates coarse sand larger than 2mm, fine sand of 0.15-2mm and mud smaller than 0.15mm.

3. The system for the complete utilization of humus soil according to claim 2, characterized in that: The drying unit includes a settling device, a mixing tank, a filter press, and a dryer connected in sequence; the hydraulic screening device and the mixing silo are both connected to the settling device, and the slurry smaller than 0.15mm after screening by the hydraulic screening device enters the settling device, and the supernatant of the settling device enters the mixing silo.

4. The system for the complete utilization of humus soil according to claim 3, characterized in that: The calcination unit includes a waste heat preheating fluidized bed calcination device; The waste heat preheating fluidized bed calcination device includes a preheating chamber and a fluidized bed calcination furnace connected in sequence, wherein the fluidized bed calcination furnace provides heat for the preheating of the preheating chamber.

5. The system for the complete utilization of humus soil according to claim 4, characterized in that: The fluidized bed calciner is connected to the dryer, and the fluidized bed calciner provides heat for the drying process of the dryer.

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