Belt sludge dryer, sludge biological treatment system and treatment method

Abstract

The application belongs to the technical field of sludge treatment equipment, and particularly discloses a belt type sludge drying machine, a sludge biological treatment system and a treatment method. The belt type sludge drying machine comprises a drying box, a belt type conveying structure, a air supply structure, a first water tank, a second water tank and a heat exchange assembly. The belt type conveying structure comprises a conveying belt and a heat pipe, and the heat pipe is in abutment with the conveying belt to heat the conveying belt. The air supply structure supplies hot air into the drying box. The heat exchange assembly comprises an evaporator, a compressor, a condenser and an expansion valve which are connected in sequence. The first water tank is connected with the water outlet end of the air supply structure and receives condensate water in the drying box. The first water tank supplies water to the water inlet end of the evaporator. The second water tank is connected with the water outlet end of the evaporator and the water inlet end of the condenser. The water outlet end of the condenser is connected with the water inlet end of the air supply structure. The belt type sludge drying machine can significantly reduce the amount of dust generated and improve the energy utilization efficiency.

Description

Technical Field

[0001] This application relates to the field of sludge drying equipment technology, and in particular to a belt sludge dryer, a sludge biological treatment system and treatment method. Background Technology

[0002] As the mainstream equipment in the field of sludge thermal drying, belt sludge dryers still face two significant technical bottlenecks in practical applications, which restrict their operational economy and stability:

[0003] I. High energy consumption costs and insufficient energy utilization efficiency

[0004] The equipment operation relies on thermal energy, and the thermal energy of traditional processes mainly comes from natural gas combustion or steam heat exchange, resulting in high energy consumption and high operating costs. Although some equipment has introduced heat pump technology to optimize energy consumption structure, existing heat pump systems mostly focus on recovering low-grade heat energy from the environment, and the recovery and utilization rate of waste heat contained in the low-temperature condensate generated during equipment operation is low. This fails to fully tap the energy potential within the system, and the efficiency of energy cascade utilization needs to be improved.

[0005] II. Significant capacity decline, prominent operation and maintenance costs and safety risks.

[0006] Traditional belt drying processes rely entirely on high-volume hot air convection drying, which directly leads to a high-concentration dust environment inside the drying chamber, causing a series of chain reactions:

[0007] A sharp drop in heat exchange efficiency: High concentrations of dust tend to adhere to the surface of heat exchanger fins, gradually forming a dense insulation layer that severely hinders heat transfer, leading to a sharp drop in heat exchange efficiency. This is the main reason why equipment capacity decreases significantly over time.

[0008] Increased equipment wear and tear: Suspended dust accelerates the wear and corrosion of critical components, such as fan impellers, transmission bearings, and housing structures, directly shortening equipment lifespan and significantly increasing equipment maintenance frequency and operating costs;

[0009] Significant safety hazards: The high-concentration dust environment inside the drying chamber poses a major safety risk of dust explosion under specific temperature and oxygen concentration conditions, directly threatening production and operation.

[0010] Currently, the industry mostly uses back-end auxiliary dust removal or cleaning methods such as dust removal scrapers and water film dust removal to address the above problems. However, these methods can only passively treat the dust that has already been generated and cannot fundamentally solve the series of problems caused by high dust environments, and their technical limitations are obvious. Summary of the Invention

[0011] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a belt sludge dryer that can significantly reduce dust generation and improve energy utilization efficiency.

[0012] This application also proposes a sludge biological treatment system and treatment method having the above-mentioned belt sludge dryer.

[0013] According to an embodiment of the first aspect of this application, a belt sludge dryer includes:

[0014] Drying box;

[0015] A belt conveyor structure includes a conveyor belt and a heat pipe, wherein the heat pipe abuts against the conveyor belt to heat the conveyor belt;

[0016] An air supply structure is installed inside the drying box, and the air supply structure supplies hot air into the drying box;

[0017] The heat exchange assembly includes an evaporator, a compressor, a condenser, and an expansion valve connected in sequence. The evaporator and the condenser are both heat exchange assemblies. The water outlet of the condenser is connected to the water inlet of the air supply structure through an intermediate pipe.

[0018] The first water tank is connected to the water outlet of the air supply structure through a first water inlet pipe and to the water inlet of the evaporator through a first water outlet pipe; the first water tank is connected to the drying box through a second water inlet pipe, and the drying box supplies condensate dripping wet sludge to the first water tank through the second water inlet pipe.

[0019] The second water tank is connected to the water outlet of the evaporator via a third water inlet pipe, and to the water inlet of the condenser via a second water outlet pipe;

[0020] The water temperature at the inlet of the evaporator is a first water temperature, the water temperature at the outlet is a second water temperature, and the water temperature at the outlet of the condenser is a third water temperature. The third water temperature is higher than the first water temperature, and the first water temperature is higher than the second water temperature.

[0021] The belt sludge dryer according to the embodiments of this application has at least the following beneficial effects:

[0022] Heat is directly transferred to the conveyor belt via thermal conduction, making the entire conveyor belt a mobile heating plate for contact conduction heating and thermal radiation heating of the wet sludge. Combined with the air supply structure, hot air is supplied to the drying chamber. Compared to traditional hot air convection drying methods, this solution reduces the circulating air volume within the drying chamber, thereby reducing dust generation and mitigating safety risks, equipment corrosion, and heat exchange component clogging caused by dust. The heat exchange components utilize the condensate in the drying chamber to exchange heat with the circulating water in the air supply structure, achieving waste heat recovery, significantly improving energy efficiency, and reducing energy consumption.

[0023] In some embodiments of this application, the heat pipe includes an outer cylinder and a heating tube, the outer cylinder defining a receiving cavity, and the heating tube being installed in the receiving cavity; the receiving cavity is filled with heat-conducting oil, and the outer surface of the outer cylinder abuts against the conveyor belt.

[0024] In some embodiments of this application, the outer cylinder and / or the conveyor belt are made of a thermally conductive metal material.

[0025] In some embodiments of this application, the belt conveyor structure further includes a drive shaft and a driven shaft, the conveyor belt is sleeved on the drive shaft and the driven shaft to form a first conveying layer and a second conveying layer, the heat pipe is installed between the first conveying layer and the second conveying layer, and the heat pipe abuts against the first conveying layer and the second conveying layer.

[0026] In some embodiments of this application, the conveyor belt is designed with a hollowed-out shape, and the heat pipe is rotatably mounted on the conveyor belt about its own axial direction.

[0027] In some embodiments of this application, at least two belt conveyor structures are provided, and the at least two belt conveyor structures are arranged at intervals in the vertical direction and staggered in the horizontal direction, with the conveying directions of adjacent belt conveyor structures being opposite.

[0028] The sludge biological treatment system according to the second aspect of this application includes:

[0029] The aforementioned belt sludge dryer;

[0030] The first mixing unit conveys a wet sludge mixture into the drying box, the wet sludge mixture comprising wet sludge and a treatment agent;

[0031] The second mixing unit mixes the dry sludge output from the drying box with additives to form a dry sludge mixture.

[0032] The pyrolysis unit pyrolyzes the dry sludge mixture to generate biochar, which is then transported to the first mixing unit.

[0033] In some embodiments of this application, the first mixing unit includes:

[0034] The first mixing and conveying mechanism mixes the wet sludge and the treatment agent, and conveys them to the drying box;

[0035] A wet sludge silo conveys wet sludge to the first mixing and conveying mechanism;

[0036] The carbon bin is connected to the pyrolysis unit and supplies the processing agent to the first mixing and conveying mechanism.

[0037] In some embodiments of this application, the additive is an iron-aluminum mixture, and the ratio of the dry sludge to the additive is 1:3.

[0038] The treatment method of the sludge biological treatment system according to the third aspect of this application is applicable to the above-mentioned sludge biological treatment system and includes the following steps:

[0039] The wet sludge bin of the first mixing unit conveys wet sludge to the feed end of the first mixing and conveying mechanism, and the carbon bin of the first mixing unit conveys treatment agent to the feed end of the first mixing and conveying mechanism. The wet sludge and treatment agent are mixed in the first mixing and conveying mechanism to form a wet sludge mixture, and the wet sludge mixture is conveyed to the feed inlet of the drying box.

[0040] The wet sludge mixture is dried into dry sludge in a drying chamber. The dry sludge is discharged from the outlet of the drying chamber and transported to the second mixing unit.

[0041] The second mixing unit mixes the dry sludge with the iron-aluminum mixture to form a dry sludge mixture, and then transports the dry sludge mixture to the pyrolysis unit;

[0042] The pyrolysis unit pyrolyzes the dry sludge mixture to prepare highly active iron-aluminum dual-doped biochar with a specific surface area greater than 100 m² / g.

[0043] Highly active iron-aluminum co-doped biochar is transported to the char bin.

[0044] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0045] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0046] Figure 1 This is a schematic diagram of the structure of a belt sludge dryer according to the first aspect of this application;

[0047] Figure 2 for Figure 1 A schematic diagram of the cross-section of the heat pipe;

[0048] Figure 3 This is a schematic diagram of the sludge biological treatment system according to a second aspect embodiment of this application.

[0049] Icon labels:

[0050] Drying box 100, inlet 110, outlet 120;

[0051] Belt conveyor structure 200, conveyor belt 210, first conveyor layer 211, second conveyor layer 212, heat pipe 220, outer cylinder 221, heating pipe 222, drive shaft 230, driven shaft 240, air supply structure 250, intermediate pipe 251;

[0052] First water tank 300, first water inlet pipe 310, second water inlet pipe 320, first water outlet pipe 330;

[0053] Second water tank 400, third water inlet pipe 410, second water outlet pipe 420;

[0054] Heat exchanger assembly 500, evaporator 510, compressor 520, condenser 530, expansion valve 540;

[0055] First mixing unit 600, first mixing and conveying mechanism 610, wet sludge bin 620, and carbon bin 630;

[0056] Second mixing unit 700;

[0057] Pyrolysis unit 800. Detailed Implementation

[0058] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0059] In the description of this application, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0060] In the description of this application, "multiple" refers to two or more. The use of "first" and "second" is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or the order in which the technical features are indicated.

[0061] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0062] Reference Figures 1 to 2 The first aspect of this application discloses a belt sludge dryer, including a drying box 100, a belt conveyor structure 200 and a heat exchange component 500. The belt conveyor structure 200 and the air supply structure 250 are both installed inside the drying box 100. The belt conveyor structure 200 is used to convey and dry sludge, and the air supply structure 250 is used to dry sludge and remove moisture from the drying box 100.

[0063] Reference Figure 1 As shown, the belt conveyor structure 200 includes a conveyor belt 210 and a heat pipe 220. The heat pipe 220 abuts against the conveyor belt 210 to heat the conveyor belt 210. The conveyor belt 210 is used to transport wet sludge. The heat pipe 220 directly heats the conveyor belt 210 through heat conduction, making the entire conveyor belt 210 a mobile heating plate. This provides contact conduction heating and thermal radiation heating for the wet sludge. Compared with the traditional hot air convection method for drying wet sludge, conduction heating and thermal radiation heating can reduce dust generation, thereby reducing the safety risks, equipment corrosion, and heat exchange component clogging problems caused by dust.

[0064] In some embodiments of this application, reference is made to Figure 1 As shown, multiple heat pipes 220 are installed along the conveying direction of the conveyor belt 210. The multiple heat pipes 220 are evenly spaced to ensure uniform heating at all locations on the conveyor belt 210, thereby improving the drying effect on the wet sludge. Preferably, the multiple heat pipes 220 use the same product and heating method to reduce manufacturing and maintenance costs.

[0065] In some embodiments of this application, the belt conveyor structure 200 further includes a drive shaft 230 and a driven shaft 240. A conveyor belt 210 is sleeved on the drive shaft 230 and the driven shaft 240 to form a first conveying layer 211 and a second conveying layer 212. A heat pipe 220 is installed between the first conveying layer 211 and the second conveying layer 212, and the heat pipe 220 abuts against the first conveying layer 211 and the second conveying layer 212. Specifically, refer to... Figure 1 As shown, the first conveying layer 211 and the second conveying layer 212 are parallel, and the first conveying layer 211 is used to receive wet sludge. Although the second conveying layer 212 does not convey wet sludge, by simultaneously heating the first conveying layer 211 and the second conveying layer 212, it can be ensured that the temperature of any position of the conveyor belt 210 is uniform and maintained at a high temperature during operation, thereby improving the drying effect of the wet sludge.

[0066] In some other embodiments of this application, the conveyor belt 210 has a composite sandwich structure, and the heat pipe 220 is installed in the sandwich of the conveyor belt 210.

[0067] In some embodiments of this application, the heat pipe 220 is preferably electrically heated; see reference Figure 2 As shown, the heat pipe 220 includes an outer cylinder 221 and heating pipes 222. The outer cylinder 221 defines a receiving cavity, and the heating pipes 222 are installed inside the receiving cavity. The receiving cavity is filled with heat-conducting oil, and the outer surface of the outer cylinder 221 abuts against the conveyor belt 210. Specifically, the number and size of the heating pipes 222 are not limited in this embodiment, and the heat-conducting oil can be a suitable product purchased according to actual conditions; for example, the heating pipes 222 can be bundled armored electric heating pipes. The heat from the heating pipes 222 is transferred to the outer cylinder 221 through the heat-conducting oil, which can quickly and evenly conduct the heat from the point-like heat source of the heating pipes 222 to the entire drum shell.

[0068] In some embodiments of this application, the outer cylinder 221 and / or the conveyor belt 210 are made of a metal thermally conductive material, such as stainless steel. The heat pipe 220 and the conveyor belt 210 made of stainless steel not only have good strength and toughness, but also have rust prevention and thermal conductivity, resulting in low production and maintenance costs.

[0069] In some embodiments of this application, the conveyor belt 210 has a hollow design, and the heat pipe 220 is axially rotatably mounted on the conveyor belt 210. Specifically, the hollow design of the conveyor belt 210 facilitates the rapid outflow of water from the wet sludge, thereby facilitating the rapid drying of the wet sludge. The size and pattern of the hollow design are not limited in this embodiment and can be specifically set according to actual conditions. Side plates are provided at both ends of the conveyor belt 210 in the width direction, and the two ends of the heat pipe 220 are respectively mounted on the two side plates of the conveyor belt 210. The axial rotatable mounting of the heat pipe 220 on the conveyor belt 210 can prevent the surface of the heat pipe 220 from sticking and dust accumulation, ensuring stable heat transfer efficiency and improving the long-term reliability of the equipment.

[0070] In some embodiments of this application, at least two belt conveyor structures 200 are provided, and the at least two belt conveyor structures 200 are arranged at intervals in the vertical direction and staggered in the horizontal direction, with the conveying directions of adjacent belt conveyor structures 200 being opposite. Specifically, refer to... Figure 1As shown, the drying box 100 is equipped with an inlet 110 and an outlet 120, both located at the same end of the drying box 100. For ease of understanding, the two belt conveyor structures 200 are defined as the first conveyor structure and the second conveyor structure, respectively, with the first conveyor structure located above the second conveyor structure. Wet sludge enters the drying box 100 through the inlet 110 and falls onto the starting end of the first conveyor structure; after the wet sludge is conveyed from the starting end to the ending end of the first conveyor structure, it falls onto the starting end of the second conveyor structure; after the wet sludge is conveyed from the starting end to the ending end of the second conveyor structure, it is discharged from the outlet 120. The wet sludge is dried during the conveying process of the first and second conveyor structures; the two belt conveyor structures 200 effectively utilize vertical space, improving space utilization.

[0071] It is conceivable that in actual production equipment, the belt conveyor structure 200 can also be configured with three, four, five, six, etc., depending on the needs.

[0072] In some embodiments of this application, a scraper structure is also installed inside the drying box 100. The scraper structure is used to periodically clean the wet sludge adhering to the conveyor belt 210. The scraper structure can adopt different shapes, sizes, or installation positions depending on the actual situation, and is not limited in this embodiment.

[0073] Traditional hot air convection drying of wet sludge involves supplying hot air into the drying chamber 100 to dry the sludge. In this solution, the drying chamber 100 also has an air supply structure 250 to supply hot air. However, because heat pipes 220 are used for both conductive and radiant heating of the wet sludge, the number of air supply structures 250 can be reduced, thereby decreasing hot air convection within the drying chamber 100 and reducing dust generation. Furthermore, the wet sludge generates steam during the drying process, resulting in high humidity within the drying chamber 100, which is detrimental to drying. The air supply structure 250 can reduce the humidity within the drying chamber 100, thus improving the drying efficiency of the wet sludge.

[0074] Reference Figure 1 As shown, even though the number of air supply structures 250 can be reduced in the belt drying device of this application embodiment, multiple air supply structures 250 still need to be installed in the drying box 100. The specific number of air supply structures 250 is not limited in this embodiment, nor is the power of the air supply structures 250 limited in this embodiment. Compared with traditional drying devices, the drying box 100 in this embodiment can install air supply structures 250 with lower power.

[0075] In some embodiments of this application, the air supply structure 250 typically includes a fan and a condenser pipe. The inlet end of the condenser pipe is connected to an intermediate pipe 251, and the outlet end is connected to a first inlet pipe 310. The intermediate pipe 251 supplies hot water at 70°C to 80°C to the condenser pipe. The fan blows air into the condenser pipe and into the drying chamber 100. Since the condenser pipe is supplied with high-temperature hot water, the air blown by the fan into the condenser pipe and then supplied into the drying chamber 100 is hot air. By blowing air into the condenser pipe through the fan, the water temperature inside the condenser pipe decreases, so the water flowing into the first inlet pipe 310 from the condenser pipe is typically warm water at 50°C to 60°C.

[0076] It is important to understand that wet sludge will drip water downwards during the drying process, so condensate will collect at the bottom of the drying chamber 100. Also, the drying chamber 100 itself has a relatively high temperature, so the temperature of the condensate is usually around 40°C.

[0077] To fully utilize the condensate in the drying chamber 100 and the residual heat of the water in the first inlet pipe 310, the belt drying device also includes a first water tank 300, a heat exchange assembly 500, and a second water tank 400. (Refer to...) Figure 1 As shown, the heat exchange assembly 500 includes an evaporator 510, a compressor 520, a condenser 530, and an expansion valve 540 connected in sequence. The evaporator 510 and the condenser 530 constitute the heat exchange assembly 500. The first water tank 300 is connected to the outlet of the air supply structure 250 via a first inlet pipe 310 and to the inlet of the evaporator 510 via a first outlet pipe 330. The first water tank 300 is connected to the drying box 100 via a second inlet pipe 320, and the drying box 100 supplies condensate formed by dripping wet sludge into the first water tank 300 via the second inlet pipe 320. The second water tank 400 is connected to the outlet of the evaporator 510 via a third inlet pipe 410 and to the inlet of the condenser 530 via a second outlet pipe 420. The outlet of the condenser 530 is connected to the inlet of the air supply structure 250 via an intermediate pipe 251.

[0078] If we define the water temperature at the inlet of the evaporator 510 as the first water temperature, the water temperature at the outlet as the second water temperature, and the water temperature at the outlet of the condenser 530 as the third water temperature, then the water temperature at the inlet of the condenser 530 is also the second water temperature, and the third water temperature is higher than the first water temperature, and the first water temperature is higher than the second water temperature.

[0079] Specifically, refer to Figure 1 As shown, the condensate at around 40°C in the drying box 100 and the water at 50°C to 60°C in the first inlet pipe 310 are mixed in the first water tank 300. Then, when the first water tank 300 supplies water to the inlet of the evaporator 510 through the first outlet pipe 330, the water temperature at the inlet of the evaporator 510 is usually 40°C to 50°C.

[0080] After heat exchange in the evaporator 510, the water temperature at the outlet of the evaporator 510 is usually 20°C to 30°C, which means the water temperature flowing into the third inlet pipe 410 is usually 20°C to 30°C, and consequently the water temperature in the second water tank 400 is 20°C to 30°C. The water temperature at the inlet of the condenser 530 is also usually 20°C to 30°C. After heat exchange in the condenser 530, the water temperature at the outlet of the condenser 530 is usually 70°C to 80°C, which means the condenser 530 supplies hot water at 70°C to 80°C to the inlet of the air supply structure 250 through the intermediate pipe 251.

[0081] The operation mode and working principle of the heat exchange component 500 in this application are as follows: Refrigerant circulates in the heat exchange component 500. The refrigerant is compressed from a high-temperature, low-pressure gas into a high-temperature, high-pressure liquid at the compressor 520. Then, the high-temperature, high-pressure liquid refrigerant is cooled into a low-temperature, high-pressure liquid refrigerant at the condenser 530. Therefore, the water supplied from the second water tank 400 to the condenser 530 will be heated into hot water by cooling the condenser 530. The low-temperature, high-pressure liquid refrigerant will become a low-temperature, low-pressure gas after passing through the expansion valve 540. Then, the low-temperature, low-pressure gaseous refrigerant will be heated into a high-temperature, low-pressure gas at the evaporator 510. Therefore, the water supplied from the first water tank 300 to the evaporator 510 will have its temperature reduced after heat exchange at the evaporator 510.

[0082] In the embodiments of this application, the waste heat of the condensate and the water in the first inlet pipe 310 is fully utilized through the heat exchange component 500, and a refined internal waste heat recovery closed loop is constructed, which significantly improves energy utilization efficiency and reduces the consumption of traditional energy sources such as natural gas and coal gas.

[0083] The sludge biological treatment system of the second aspect of this application, referring to... Figure 3 As shown, the system includes the aforementioned belt sludge dryer, a first mixing unit 600, a second mixing unit 700, and a pyrolysis unit 800. The first mixing unit 600 conveys a wet sludge mixture into the drying chamber 100, which includes wet sludge and a treatment agent. The second mixing unit 700 mixes the dry sludge output from the drying chamber 100 with additives to form a dry sludge mixture. The pyrolysis unit 800 pyrolyzes the dry sludge mixture to generate biochar, which is then conveyed to the first mixing unit 600.

[0084] In some embodiments of this application, the first mixing unit 600 includes a first mixing and conveying mechanism 610, a wet sludge bin 620, and a carbon bin 630, as shown in the reference. Figure 3As shown, the first mixing and conveying mechanism 610 mixes wet sludge and treatment agent and conveys them to the drying box 100. The wet sludge bin 620 conveys wet sludge to the first mixing and conveying mechanism 610. The carbon bin 630 is connected to the pyrolysis unit 800 and conveys the treatment agent to the first mixing and conveying mechanism 610. The first mixing and conveying mechanism 610 can be a twin-shaft screw conveyor. The wet sludge and treatment agent are mixed in the first mixing and conveying mechanism 610 and then conveyed to the drying box 100.

[0085] In some embodiments of this application, the additive is an iron-aluminum mixture, and the ratio of dry sludge to additive is typically set at 1:3. Then, the pyrolysis unit 800 prepares highly active iron-aluminum dual-doped biochar with a specific surface area greater than 100 m² / g. The treatment agent can be a chemical dehydrating agent such as polyacrylamide, or highly active iron-aluminum dual-doped biochar, or a mixture of both. Traditional carbon bins 630 use chemical dehydrating agents such as polyacrylamide. By partially or completely replacing the chemical dehydrating agents such as polyacrylamide with the highly active iron-aluminum dual-doped biochar produced by pyrolysis, internal recycling of waste resources is achieved, significantly reducing waste emissions, lowering equipment operating costs, and being more environmentally friendly.

[0086] The treatment method of the sludge biological treatment system according to the third aspect of this application is applicable to the above-mentioned sludge biological treatment system and includes the following steps:

[0087] S1. The wet sludge bin 620 of the first mixing unit 600 conveys wet sludge to the feed end of the first mixing and conveying mechanism 610, and the carbon bin 630 of the first mixing unit 600 conveys treatment agent to the feed end of the first mixing and conveying mechanism 610. The wet sludge and treatment agent are mixed in the first mixing and conveying mechanism 610 to form a wet sludge mixture, and the wet sludge mixture is conveyed to the feed port of the drying box 200.

[0088] S2. The wet sludge mixture is dried into dry sludge in the drying box 200. The dry sludge is discharged from the outlet of the drying box 200 and transported to the second mixing unit 700.

[0089] S3, the second mixing unit 700 mixes the dry sludge with the iron-aluminum mixture to form a dry sludge mixture, and then transports the dry sludge mixture to the pyrolysis unit 800;

[0090] S4, pyrolysis unit 800 pyrolyzes dry sludge mixture to prepare highly active iron-aluminum dual-doped biochar with a specific surface area greater than 100m² / g.

[0091] S5, highly active iron-aluminum dual-doped biochar is transported to the charcoal bin 630.

[0092] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine the different embodiments or examples described in this specification.

[0093] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.

Claims

1. A belt type sludge drier characterized by, include: Drying box; A belt conveyor structure includes a conveyor belt and a heat pipe, wherein the heat pipe abuts against the conveyor belt to heat the conveyor belt; An air supply structure is installed inside the drying box, and the air supply structure supplies hot air into the drying box; The heat exchange assembly includes an evaporator, a compressor, a condenser, and an expansion valve connected in sequence. The evaporator and the condenser are both heat exchange assemblies. The water outlet of the condenser is connected to the water inlet of the air supply structure through an intermediate pipe. The first water tank is connected to the water outlet of the air supply structure through a first water inlet pipe and to the water inlet of the evaporator through a first water outlet pipe; the first water tank is connected to the drying box through a second water inlet pipe, and the drying box supplies condensate dripping wet sludge to the first water tank through the second water inlet pipe. The second water tank is connected to the water outlet of the evaporator via a third water inlet pipe, and to the water inlet of the condenser via a second water outlet pipe; The water temperature at the inlet of the evaporator is a first water temperature, the water temperature at the outlet is a second water temperature, and the water temperature at the outlet of the condenser is a third water temperature. The third water temperature is higher than the first water temperature, and the first water temperature is higher than the second water temperature.

2. The belt sludge dryer according to claim 1, characterized in that The heat pipe includes an outer cylinder and a heating tube. The outer cylinder defines a receiving cavity, and the heating tube is installed in the receiving cavity. The receiving cavity is filled with heat-conducting oil, and the outer surface of the outer cylinder abuts against the conveyor belt.

3. The belt sludge dryer according to claim 2, characterized in that The outer cylinder and / or the conveyor belt are made of a thermally conductive metal material.

4. The belt sludge dryer according to claim 1, characterized in that The belt conveyor structure further includes a drive shaft and a driven shaft. The conveyor belt is sleeved on the drive shaft and the driven shaft to form a first conveying layer and a second conveying layer. The heat pipe is installed between the first conveying layer and the second conveying layer and abuts against the first conveying layer and the second conveying layer.

5. The belt sludge dryer according to claim 1, characterized in that The conveyor belt has a hollow design, and the heat pipe is mounted on the conveyor belt in a rotatable manner around its own axis.

6. The belt sludge dryer according to claim 1, characterized in that At least two belt conveyor structures are provided, and the at least two belt conveyor structures are arranged at intervals in the vertical direction and staggered in the horizontal direction, with the conveying directions of adjacent belt conveyor structures being opposite.

7. A sludge biological treatment system, characterized by comprising: include: The belt sludge dryer according to any one of claims 1 to 6; The first mixing unit conveys a wet sludge mixture into the drying box, the wet sludge mixture comprising wet sludge and a treatment agent; The second mixing unit mixes the dry sludge output from the drying box with additives to form a dry sludge mixture. The pyrolysis unit pyrolyzes the dry sludge mixture to generate biochar, which is then transported to the first mixing unit.

8. The sludge biological treatment system according to claim 7, characterized by The first mixing unit includes: The first mixing and conveying mechanism mixes the wet sludge and biochar and conveys them to the drying box; A wet sludge silo conveys wet sludge to the first mixing and conveying mechanism; The biochar bin is connected to the pyrolysis unit and supplies biochar to the first mixing and conveying mechanism.

9. The sludge biological treatment system according to claim 7, characterized by The additive is an iron-aluminum mixture, and the ratio of the dry sludge to the additive is 1:

3.

10. A method of treatment of a sludge biological treatment system, characterized in that, The sludge biological treatment system according to any one of claims 7 to 9 includes the following steps: The wet sludge bin of the first mixing unit delivers wet sludge to the feeding end of the first mixing conveying mechanism, and the carbon bin of the first mixing unit delivers additive to the feeding end of the first mixing conveying mechanism. The wet sludge and the additive are mixed in the first mixing conveying mechanism to form wet sludge mixture, and the wet sludge mixture is delivered to the feeding port of the drying box. The wet sludge mixture is dried in the drying box into dry sludge, which is discharged from the discharging port of the drying box and delivered to the second mixing unit. The second mixing unit mixes the dry sludge with the iron-aluminum mixture to form dry sludge mixture, and delivers the dry sludge mixture to the pyrolysis unit. The pyrolysis unit pyrolyzes the dry sludge mixture to prepare high-activity iron-aluminum double-doped biochar additive with a specific surface area greater than 100 m² / g. The high-activity iron-aluminum double-doped biochar additive is delivered to the carbon bin of the first mixing conveying mechanism.

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