Preparation device of wet chicken manure dispersion granules and continuous preparation method thereof

Abstract

This invention provides a device and continuous preparation method for wet chicken manure dispersed granules. It employs a granulation mechanism combining wet core extrusion with dry powder gravity-free coating, rapidly forming a dry shell structure on the surface of the high-moisture wet core within a twin-shaft gravity-free mixer. Through closed-loop powder return control, the undersize fine powder is simultaneously used as coating material and granulation seed powder, significantly reducing the drying load and achieving material recycling. Multi-stage through-flow low-temperature drying with bed permeability as an online control index maintains a high porosity in the dispersed granule bed, enabling rapid dehydration at 40-70℃. Compared to traditional drum drying, energy consumption is reduced by 20%-30%, ammonia volatilization loss is reduced by more than 40%, and the finished granules are uniform, with a moisture content ≤30% and no agglomeration, meeting the requirements of NY / T 525-2021 standard. This achieves continuous, low-carbon, and high-quality granulation production of high-moisture wet chicken manure.

Description

Technical Field

[0001] This invention relates to the technical field of livestock and poultry manure resource utilization and organic fertilizer preparation equipment, and in particular to a device for preparing wet chicken manure dispersed granules and its continuous preparation method. Background Technology

[0002] Utilization is an important direction in the field of organic fertilizer production, with caged chicken manure attracting much attention due to its high yield and nutrient content. Currently, commercial organic fertilizers must meet the requirements of standards such as NY / T 525-2021 regarding moisture content (fresh sample ≤30%), fecal coliform count, ascarid egg mortality rate, and organic matter content. Existing chicken manure granulation production lines often employ a process route combining extrusion granulation with drum drying, or a process of rotary drum / disc granulation followed by two stages of high-temperature drying. For example, extrusion granulation typically involves directly extruding fermented or dehydrated chicken manure powder into cylindrical granules, followed by drying in a drum dryer at 60-80℃; rotary drum granulation requires adding water or introducing steam to the material to improve pelleting rate, followed by high-temperature drying and anti-caking treatment. In recent years, some studies have also explored utilizing waste heat from livestock sheds for low-temperature drying to reduce energy consumption.

[0003] However, the aforementioned existing technologies still have the following problems in practical applications: First, the original moisture content of raw chicken manure can be as high as 65%-75%. High-moisture materials are prone to sticking and clumping during granulation, resulting in poor permeability of the granule bed and low heat and mass transfer efficiency during drying. To ensure that the final moisture content meets the standard, it is often necessary to increase the drying temperature or extend the drying time, which leads to high energy consumption. Second, high-temperature drying (especially above 70℃) will accelerate the volatilization loss of ammonium nitrogen in chicken manure. Studies have shown that increased temperature significantly increases the risk of nitrogen loss. At the same time, high temperature may also affect the activity of organic matter and reduce the agronomic value of fertilizer. Third, traditional anti-caking measures mostly rely on end coating or post-treatment coating, which cannot fundamentally solve the sticking problem in the early stages of granulation and drying, and increases the complexity and cost of the process. In addition, existing powder return technology mainly returns the undersize fine powder to the extrusion granulator as a reprocessing raw material, failing to fully utilize its dual function as a coating material and granulation seed.

[0004] Therefore, there is an urgent need in this field to develop a continuous granulation preparation technology for chicken manure that can effectively suppress nitrogen loss and meet hygiene standards while reducing adhesion and drying energy consumption. Summary of the Invention

[0005] The purpose of this invention is to provide an apparatus for preparing wet chicken manure dispersed granules and a continuous preparation method thereof, so as to solve the problems existing in the prior art.

[0006] To achieve the above objectives, the present invention provides the following solution: The present invention provides an apparatus for preparing wet chicken manure dispersed particles, comprising a wet chicken manure extrusion forming unit, a powder coating and dispersion unit, a through-flow low-temperature drying unit, a sieving and powder return unit, and an online detection and closed-loop control unit connected in sequence. The wet chicken manure extrusion forming unit includes a twin-screw wet material extruder and a rotary cutter device. The outlet end of the twin-screw wet material extruder is equipped with a perforated plate mold, and the rotary cutter device is installed at the outlet of the perforated plate mold. The powder coating and dispersion unit includes a twin-shaft zero-gravity mixer, which has a wet core particle inlet and a dry chicken manure powder inlet at the top and an outlet at the bottom; The through-flow low-temperature drying unit is a multi-section through-flow belt dryer, which includes several independently temperature-controlled stainless steel mesh belts, circulating fans, heat exchangers and dehumidifying fans, with a uniform air distribution plate above the mesh belts. The screening and return powder unit includes a multi-layer drum screen and a return powder screw conveyor. The screen has an oversize material outlet, a middle material outlet and an undersize material outlet. The undersize material outlet is connected to the return powder screw conveyor. The discharge end of the return powder screw conveyor is connected to the dry chicken manure powder inlet of the twin-shaft zero-gravity mixer. The online detection and closed-loop control unit includes a PLC controller and a wet core moisture content sensor, a mixer humidity sensor, a dryer inlet / outlet material moisture content sensor, and a bed pressure differential sensor, all electrically connected to the PLC controller.

[0007] Preferably, the aperture of the perforated plate mold is 6-12mm, and the length of the wet core particles obtained by the rotary cutter is 8-15mm.

[0008] Preferably, the dual-shaft zero-gravity mixer is equipped with two counter-rotating blade shafts with a rotational speed of 50-150 rpm; the dry chicken manure powder inlet is located at the center of the top of the mixer, and the wet core particle inlet is located on one side of the dry chicken manure powder inlet.

[0009] Preferably, the through-flow low-temperature drying unit is composed of 3-4 independently temperature-controlled stainless steel mesh belts connected in series. Each mesh belt is equipped with a uniform air distribution plate above it, and a circulating fan and heat exchanger are correspondingly provided below the mesh belt. The dehumidification fan is located at the top of the dryer. The feed end of the dryer is equipped with a material distributor, and the discharge end is connected to a vibrating feeder.

[0010] Preferably, the multi-layer drum screen is provided with two layers of screens, the upper screen has a mesh size of 6mm and the lower screen has a mesh size of 2mm; the outlet of the oversize material corresponds to particles with a particle size >6mm, the outlet of the middle material corresponds to particles with a particle size of 2-6mm, and the outlet of the undersize material corresponds to fine powder with a particle size <2mm.

[0011] This invention also provides a continuous preparation method for wet chicken manure dispersed particles using an apparatus for preparing wet chicken manure dispersed particles, comprising the following steps: (1) Extrusion and cutting of wet chicken manure: Wet chicken manure with a moisture content of 65%-75% is fed into a twin-screw wet material extruder, extruded into strips through a perforated die, and cut into cylindrical wet core particles by a rotary cutter device; (2) Dry powder coating granulation: The wet core granules obtained in step (1) are continuously fed into a twin-shaft zero-gravity mixer. At the same time, dry chicken manure powder from the return powder screw conveyor is added to the mixer at a wet core to dry powder mass ratio of 1:0.5-1.5. The twin shafts rotate in opposite directions to throw the material to form a suspended fluidized layer, so that the dry powder is evenly adhered to the surface of the wet core to form a dry shell structure. After mixing for 30-60 seconds, free-flowing dispersed granules are obtained. (3) Through-flow low-temperature segmented drying: The dispersed particles obtained in step (2) are evenly spread on the mesh belt of the through-flow belt dryer by a distributor. The material layer thickness is 50-80mm. The particles pass through the first, second and third drying zones in sequence. The air temperature in the first zone is 40-50℃ and the air velocity is 0.8-1.2m / s. The air temperature in the second zone is 50-60℃ and the air velocity is 0.6-1.0m / s. The air temperature in the third zone is 60-70℃ and the air velocity is 0.5-0.8m / s. A uniform humidity zone is set at the outlet of each zone. The total drying time is 20-40 minutes to obtain dried particles with a moisture content of ≤30%. (4) Screening and return powder: The dried granules obtained in step (3) are fed into a multi-layer drum screen to screen out large granules with a particle size >6mm, finished granules with a particle size of 2-6mm and fine powder with a particle size <2mm. The fine powder with a particle size <2mm is returned to the twin-shaft zero-gravity mixer in step (2) by the return powder screw conveyor for recycling. (5) Closed-loop control: Data is collected in real time by the wet core moisture content sensor, the humidity sensor in the mixer, the moisture content sensor of the material at the dryer inlet / outlet and the bed pressure differential sensor and transmitted to the PLC controller. The PLC controller automatically adjusts the extrusion speed, the mixer speed, the return powder feed rate and the drying air temperature and speed according to the set values.

[0012] Preferably, in step (2), the moisture content of the dried chicken manure powder is ≤12% and the fineness is ≤2mm.

[0013] Preferably, in step (3), the uniformly moistened zone after each drying zone is a non-heated turning zone, and the dwell time is 5-10 minutes.

[0014] Preferably, in step (4), large particles with a diameter >6mm are crushed and returned to the extruder in step (1) or used as recycled powder.

[0015] Preferably, in step (5), the PLC controller has three control loops: a coating quality loop, which adjusts the speed of the return powder feeding screw according to the humidity sensor signal in the mixer; a drying permeability loop, which increases the speed of the mixer or increases the return powder ratio when the pressure difference is higher than the set value according to the bed pressure difference sensor signal; and a finished product moisture loop, which adjusts the mesh belt speed or the final air temperature according to the moisture content sensor signal at the dryer outlet.

[0016] The present invention achieves the following beneficial technical effects compared to the prior art: This invention provides a preparation device and continuous preparation method for wet chicken manure dispersed granules. It employs a granulation mechanism combining wet core extrusion with dry powder gravity-free coating. Within a biaxial gravity-free mixer, a dry shell structure is rapidly formed on the surface of the high-moisture wet core, achieving anti-adhesion and anti-caking from the source, avoiding the lag of traditional end-coating or simple high-temperature drying. Through closed-loop powder return control, the undersize fine powder is used simultaneously as coating material and granulation seed powder, significantly reducing the drying load and achieving material recycling. Multi-stage through-flow low-temperature drying with bed permeability as an online control index maintains a high porosity in the dispersed granule bed, enabling rapid dehydration at 40-70℃. Compared to traditional drum drying, energy consumption is reduced by 20%-30%, ammonia volatilization loss is reduced by more than 40%, and the finished granules are uniform (2-6mm percentage ≥85%), with a moisture content ≤30% and no adhesion or agglomeration, meeting NY / T standards. The 525-2021 standard requires the continuous, low-carbon, and high-quality granular production of high-moisture chicken manure. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the structure of the apparatus for preparing wet chicken manure dispersed particles provided by the present invention; Figure 2 This is a flowchart illustrating the continuous preparation method of wet chicken manure dispersed particles provided by the present invention. Detailed Implementation

[0019] Unless otherwise specified, the terms "connection" and "linkage" used in this application include both direct and indirect connections (linkages). In the description of this invention, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the invention and for 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. Therefore, they should not be construed as limitations on the invention.

[0020] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The purpose of this invention is to provide an apparatus for preparing wet chicken manure dispersed granules and a continuous preparation method thereof, so as to solve the problems existing in the prior art.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] like Figure 1As shown, this invention provides an apparatus for preparing wet chicken manure dispersed granules. The apparatus includes a wet chicken manure extrusion forming unit 1, a powder coating and dispersion unit 2, a through-flow low-temperature drying unit 3, a sieving and powder return unit 4, and an online detection and closed-loop control unit 5, connected in sequence. The wet chicken manure extrusion forming unit includes a twin-screw wet material extruder and a rotary cutter device. The outlet end of the twin-screw wet material extruder is equipped with a perforated die with a perforation diameter of 6 to 12 mm. The rotary cutter device is installed at the outlet of the perforated die and is used to cut the extruded strip material into cylindrical wet core granules with a length of 8 to 15 mm. The powder coating and dispersion unit includes a twin-shaft zero-gravity mixer. The mixer has a wet core particle inlet and a dry chicken manure powder inlet at the top. The dry chicken manure powder inlet is located in the center of the top of the mixer, and the wet core particle inlet is located to one side of the dry chicken manure powder inlet. The twin-shaft zero-gravity mixer contains two counter-rotating paddle shafts, the speed of which can be adjusted from 50 to 150 revolutions per minute. A discharge port is located at the bottom of the mixer. The through-flow low-temperature drying unit is a multi-stage through-flow belt dryer, consisting of 3 to 4 independently temperature-controlled stainless steel mesh belts connected in series. Each mesh belt section has a uniform air distribution plate above it, and a circulating fan and heat exchanger are located below the mesh belts. An exhaust fan is located at the top of the dryer. A distributor is located at the feed end of the dryer, and a vibrating feeder is connected to the discharge end. The screening and return powder unit includes a multi-layer drum screen and a return powder screw conveyor. The multi-layer drum screen has two layers of screens, with the upper screen having a mesh size of 6 mm and the lower screen having a mesh size of 2 mm. The screen has corresponding outlets for oversize, middle size, and undersize. The oversize outlet is for particles with a particle size greater than 6 mm, the middle size outlet is for finished particles with a particle size of 2 to 6 mm, and the undersize outlet is for fine powder with a particle size less than 2 mm. The undersize outlet is connected to the return powder screw conveyor, and the discharge end of the return powder screw conveyor is connected to the dry chicken manure powder inlet of the twin-shaft zero-gravity mixer. The online detection and closed-loop control unit includes a PLC controller and a wet core moisture content sensor, a humidity sensor inside the mixer, a material moisture content sensor at the dryer inlet and outlet, and a bed pressure differential sensor, all electrically connected to the PLC controller. These sensors are respectively arranged at the outlet of the wet chicken manure extrusion forming unit, inside the twin-shaft zero-gravity mixer, at the inlet and outlet of the through-flow low-temperature drying unit, and in the bed gaps below the dryer mesh belt.

[0025] Figure 2 The flowchart below shows the continuous preparation method of wet chicken manure dispersed particles provided by the present invention. The method will be described in detail below with reference to several embodiments.

[0026] Example 1 This embodiment utilizes the aforementioned wet chicken manure dispersion granule preparation device for continuous production. First, fresh wet chicken manure collected from the farm is pre-treated to remove large foreign objects and feathers, resulting in an initial moisture content of 72%. The wet chicken manure is then fed into a twin-screw wet extruder, extruded into strips through an 8mm orifice die, and then cut into cylindrical wet core granules approximately 10mm in length by a rotary cutter. These wet core granules continuously fall into a twin-shaft zero-gravity mixer via a vibrating conveyor. Simultaneously, dry chicken manure powder from a return screw conveyor is added through the dry chicken manure powder inlet at the top of the mixer. This returned dry chicken manure powder has a moisture content of 10% and a fineness of less than 2mm. The mass ratio of wet core to dry powder is 1:1.0. The two paddle shafts inside the twin-shaft zero-gravity mixer rotate in opposite directions at a speed of 90 revolutions per minute, scattering the material to form a suspended fluidized layer. The wet core particles are uniformly coated with dry powder on their surface during high-speed collisions, forming a dense dry shell structure. After a mixing time of about 45 seconds, free-flowing dispersed particles are obtained. At this time, the particle surface is dry and there is no adhesion.

[0027] The dispersed particles are conveyed by a belt conveyor to the distributor of the through-flow low-temperature drying unit, where they are evenly spread on the first section of the stainless steel mesh belt, with the material layer thickness controlled at 65 mm. The dryer has three independently temperature-controlled drying sections, with the following operating parameters: Section 1: air temperature 45 degrees Celsius, air velocity 1.0 m / s; Section 2: air temperature 55 degrees Celsius, air velocity 0.8 m / s; Section 3: air temperature 65 degrees Celsius, air velocity 0.6 m / s. Each drying section is followed by a moisture equalization zone, which is a non-heated, agitated zone with a residence time of 7 minutes to ensure sufficient moisture balance within the particles. The total drying time is 30 minutes. The outlet temperature of the dried particles is approximately 42 degrees Celsius, and sampling tests show a moisture content of 28%, meeting the requirements for subsequent screening.

[0028] The dried granules are fed into a multi-layer drum screen via a vibrating feeder. The oversize particles are larger than 6 mm; these are crushed and returned to the extruder for reprocessing. The middle-size particles are finished granules with a diameter of 2 to 6 mm, collected and packaged as organic fertilizer. The undersize particles are fine powder with a diameter of less than 2 mm. This fine powder is returned to the dry chicken manure powder inlet of the twin-shaft zero-gravity mixer via a return powder screw conveyor, achieving recycling. Throughout the production process, the online detection and closed-loop control unit operates automatically: a wet core moisture content sensor monitors the moisture change of the wet core at the extruder outlet in real time; a humidity sensor in the mixer detects the humidity during the coating process; moisture content sensors at the dryer inlet and outlet measure the moisture content of the feed and discharge materials respectively; and a bed pressure differential sensor monitors the permeability of the material layer on the conveyor belt. The PLC controller automatically adjusts the screw speed of the extruder, the paddle speed of the mixer, the return powder feed screw speed, and the drying air temperature and velocity of each section according to set values. Specifically, when the humidity sensor inside the mixer detects excessively high humidity, the PLC controller increases the amount of returned powder feed; when the bed differential pressure sensor detects a differential pressure higher than the set value, the PLC controller appropriately increases the mixer speed or increases the returned powder ratio to improve particle dispersibility; when the moisture content of the material at the dryer outlet exceeds 30%, the PLC controller reduces the conveyor belt speed or increases the final air temperature. In this embodiment, after 8 hours of continuous operation, approximately 24 tons of wet chicken manure were processed, producing approximately 9.6 tons of finished pellets. Particles with a diameter of 2 to 6 mm accounted for 87% of the finished product, and the moisture content was between 28% and 30%. The pellets had smooth surfaces and no clumping. Testing showed that all indicators met the requirements of the NY / T 525-2021 standard.

[0029] Example 2 The difference between this embodiment and Embodiment 1 lies in the adjustment of process parameters. The initial moisture content of the wet chicken manure is 68%. The orifice diameter of the twin-screw wet material extruder is 10 mm, and the length of the wet core particles after cutting is 12 mm. In the twin-shaft zero-gravity mixer, the mass ratio of wet core to dry powder is 1:0.8, the mixer speed is 120 rpm, and the mixing time is 35 seconds. The through-flow low-temperature dryer has four drying sections, with the following parameters: Section 1: air temperature 42 degrees Celsius, air velocity 1.1 m / s; Section 2: air temperature 52 degrees Celsius, air velocity 0.9 m / s; Section 3: air temperature 62 degrees Celsius, air velocity 0.7 m / s; Section 4: air temperature 68 degrees Celsius, air velocity 0.5 m / s. The residence time in the uniform moisture zone after each section is 6 minutes, the total drying time is 25 minutes, and the material layer thickness is 70 mm. The moisture content of the dried particles is 29%. After screening, the proportion of particles with a diameter of 2 to 6 mm in the finished product is 89%. This embodiment operates continuously for 6 hours, processing approximately 18 tons of wet chicken manure and producing approximately 7.2 tons of finished pellets. Throughout the process, the closed-loop control system operates stably, reducing drying energy consumption by approximately 25% and ammonia volatilization loss by approximately 42% compared to traditional drum drying processes.

[0030] Example 3 The difference between this embodiment and Embodiment 1 lies in the use of a lower coating ratio and a longer mixing time. The initial moisture content of the wet chicken manure was 75%. The perforated plate mold had a hole diameter of 6 mm, and the wet core particle length was 8 mm. The mass ratio of wet core to dry powder was 1:1.3, the mixer speed was 60 rpm, and the mixing time was 55 seconds. A three-stage drying process was used in the through-flow low-temperature dryer: the first stage had an air temperature of 48 degrees Celsius and an air velocity of 0.9 m / s; the second stage had an air temperature of 58 degrees Celsius and an air velocity of 0.7 m / s; and the third stage had an air temperature of 70 degrees Celsius and an air velocity of 0.6 m / s. The residence time in the uniform moisture zone was 8 minutes, the total drying time was 38 minutes, and the material layer thickness was 55 mm. The moisture content of the dried particles was 27%. After screening, 86% of the finished particles had a particle size of 2 to 6 mm. This embodiment operated continuously for 10 hours, processing approximately 30 tons of wet chicken manure and producing approximately 11 tons of finished particles. Due to the high proportion of returned powder and good coating effect, no adhesion or clumping occurred during the drying process, and the bed pressure difference remained at a low level.

[0031] Example 4 This embodiment optimizes the processing of the returned powder after screening. Building upon Example 1, large particles larger than 6 mm are crushed to below 2 mm using a separate crusher, and then combined with the undersize fine powder for use as dry chicken manure returned powder. This operation further improves the utilization rate of the returned powder and reduces material waste. Simultaneously, based on feedback from the bed pressure differential sensor, when the pressure differential increases, the PLC controller automatically increases the returned powder ratio and the mixer speed, improving the uniformity of the dispersed particles. This embodiment, running continuously for 12 hours, processes approximately 36 tons of wet chicken manure, producing approximately 14.5 tons of finished pellets, with a finished product qualification rate approximately 3% higher than that of Example 1.

[0032] Example 5 This embodiment employed a lower drying temperature and a longer drying time to verify the feasibility under low-temperature conditions. The initial moisture content of the wet chicken manure was 70%. The perforated plate mold had a hole diameter of 12 mm, and the wet core particle length was 15 mm. The mass ratio of wet core to dry powder was 1:1.5, the mixer speed was 50 rpm, and the mixing time was 60 seconds. The through-flow low-temperature dryer was set with three drying stages: the first stage had an air temperature of 40 degrees Celsius and an air velocity of 1.2 m / s; the second stage had an air temperature of 50 degrees Celsius and an air velocity of 1.0 m / s; and the third stage had an air temperature of 60 degrees Celsius and an air velocity of 0.8 m / s. The residence time in the uniform moisture zone was 10 minutes, the total drying time was 40 minutes, and the material layer thickness was 80 mm. After drying, the particle moisture content was 30%, which just met the standard requirements. After sieving, the proportion of particles with a diameter of 2 to 6 mm in the finished product was 85%. Although the drying time was longer, the ammonia volatilization loss was significantly reduced. Tests showed that ammonia loss was reduced by approximately 48% compared to the traditional high-temperature drying process, and the organic matter retention rate in the finished product was higher.

[0033] Example 6 This embodiment demonstrates the device's adaptive capability in responding to fluctuations in the moisture content of wet chicken manure. When the moisture content of the wet chicken manure suddenly increases from 72% to 75%, the wet core moisture content sensor immediately transmits a signal to the PLC controller. The controller automatically increases the return feed rate, adjusting the mass ratio of wet core to dry powder from 1:1.0 to 1:1.2, and simultaneously increases the mixer speed from 90 rpm to 110 rpm to ensure the coating effect is not affected. After the moisture content sensor at the dryer inlet detects an increase in feed moisture, the PLC controller appropriately reduces the conveyor belt speed and increases the final air temperature, keeping the moisture content of the outlet material stable below 30%. The entire adjustment process is completed within 2 minutes, with no interruptions or product defects in the production line, fully demonstrating the intelligent control advantages of the device of this invention.

[0034] The equipment used in the above embodiments is the wet chicken manure dispersion granule preparation device provided by the present invention. Each unit is connected by a closed transition hopper or flexible connection, effectively preventing dust escape. The overall production line layout adopts a configuration where the wet core forming unit is located on a second-level platform, and other units are connected horizontally in series. The material flows from top to bottom or horizontally, resulting in a compact and reasonable layout. Through the verification of the above embodiments, the device and method of the present invention can stably process wet chicken manure with an initial moisture content as high as 65% to 75%, achieving efficient drying under low-temperature conditions of 40 to 70 degrees Celsius. The moisture content of the finished granules can be controlled below 30%, resulting in uniform granules without adhesion or clumping, and significantly reduced nitrogen loss, demonstrating good prospects for industrial application.

[0035] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0036] It should be noted that the components mentioned in the above embodiments are all general standard parts or components known to those skilled in the art. Their structures and principles can be learned by those skilled in the art through technical manuals or conventional experimental methods.

[0037] This invention has illustrated its principles and implementation methods using specific examples. The descriptions of these embodiments are merely illustrative of the method and its core ideas; furthermore, those skilled in the art will recognize that modifications may be made to the specific implementation methods and application scope based on the principles of this invention. Therefore, the content of this specification should not be construed as limiting the invention.

Claims

1. An apparatus for preparing wet chicken manure dispersed granules, characterized in that, It includes a wet chicken manure extrusion forming unit, a powder coating and dispersion unit, a through-flow low-temperature drying unit, a screening and powder return unit, and an online detection and closed-loop control unit connected in sequence; The wet chicken manure extrusion forming unit includes a twin-screw wet material extruder and a rotary cutter device. The outlet end of the twin-screw wet material extruder is equipped with a perforated plate mold, and the rotary cutter device is installed at the outlet of the perforated plate mold. The powder coating and dispersion unit includes a twin-shaft zero-gravity mixer, which has a wet core particle inlet and a dry chicken manure powder inlet at the top and an outlet at the bottom; The through-flow low-temperature drying unit is a multi-section through-flow belt dryer, which includes several independently temperature-controlled stainless steel mesh belts, circulating fans, heat exchangers and dehumidifying fans, with a uniform air distribution plate above the mesh belts. The screening and return powder unit includes a multi-layer drum screen and a return powder screw conveyor. The screen has an oversize material outlet, a middle material outlet and an undersize material outlet. The undersize material outlet is connected to the return powder screw conveyor. The discharge end of the return powder screw conveyor is connected to the dry chicken manure powder inlet of the twin-shaft zero-gravity mixer. The online detection and closed-loop control unit includes a PLC controller and a wet core moisture content sensor, a mixer humidity sensor, a dryer inlet / outlet material moisture content sensor, and a bed pressure differential sensor, all electrically connected to the PLC controller.

2. The apparatus for preparing wet chicken manure dispersed granules according to claim 1, characterized in that, The perforated plate mold has a hole diameter of 6-12mm, and the wet core particles obtained by the rotary cutter device have a length of 8-15mm.

3. The apparatus for preparing wet chicken manure dispersed granules according to claim 1, characterized in that, The dual-shaft zero-gravity mixer is equipped with two counter-rotating blade shafts with a rotation speed of 50-150 rpm; the dry chicken manure powder inlet is located at the center of the top of the mixer, and the wet core particle inlet is located on one side of the dry chicken manure powder inlet.

4. The apparatus for preparing wet chicken manure dispersed granules according to claim 1, characterized in that, The through-flow low-temperature drying unit consists of 3-4 independently temperature-controlled stainless steel mesh belts connected in series. Each mesh belt is equipped with a uniform air distribution plate above it, and a circulating fan and heat exchanger are correspondingly installed below the mesh belt. The dehumidification fan is located at the top of the dryer. The feed end of the dryer is equipped with a material distributor, and the discharge end is connected to a vibrating feeder.

5. The apparatus for preparing wet chicken manure dispersed granules according to claim 1, characterized in that, The multi-layer drum screen is equipped with two layers of screens. The upper screen has a mesh size of 6mm and the lower screen has a mesh size of 2mm. The outlet of the oversize material corresponds to particles with a particle size >6mm, the outlet of the middle material corresponds to particles with a particle size of 2-6mm, and the outlet of the undersize material corresponds to fine powder with a particle size <2mm.

6. A continuous method for preparing wet chicken manure dispersed particles using the apparatus for preparing wet chicken manure dispersed particles according to any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Extrusion and cutting of wet chicken manure: Wet chicken manure with a moisture content of 65%-75% is fed into a twin-screw wet material extruder, extruded into strips through a perforated die, and cut into cylindrical wet core particles by a rotary cutter device; (2) Dry powder coating granulation: The wet core granules obtained in step (1) are continuously fed into a twin-shaft zero-gravity mixer. At the same time, dry chicken manure powder from the return powder screw conveyor is added to the mixer at a wet core to dry powder mass ratio of 1:0.5-1.

5. The twin shafts rotate in opposite directions to throw the material to form a suspended fluidized layer, so that the dry powder is evenly adhered to the surface of the wet core to form a dry shell structure. After mixing for 30-60 seconds, free-flowing dispersed granules are obtained. (3) Through-flow low-temperature segmented drying: The dispersed particles obtained in step (2) are evenly spread on the mesh belt of the through-flow belt dryer by a distributor. The material layer thickness is 50-80mm. The particles pass through the first, second and third drying zones in sequence. The air temperature in the first zone is 40-50℃ and the air velocity is 0.8-1.2m / s. The air temperature in the second zone is 50-60℃ and the air velocity is 0.6-1.0m / s. The air temperature in the third zone is 60-70℃ and the air velocity is 0.5-0.8m / s. A uniform humidity zone is set at the outlet of each zone. The total drying time is 20-40 minutes to obtain dried particles with a moisture content of ≤30%. (4) Screening and return powder: The dried granules obtained in step (3) are fed into a multi-layer drum screen to screen out large granules with a particle size >6mm, finished granules with a particle size of 2-6mm and fine powder with a particle size <2mm. The fine powder with a particle size <2mm is returned to the twin-shaft zero-gravity mixer in step (2) by the return powder screw conveyor for recycling. (5) Closed-loop control: Data is collected in real time by the wet core moisture content sensor, the humidity sensor in the mixer, the moisture content sensor of the material at the dryer inlet / outlet and the bed pressure differential sensor and transmitted to the PLC controller. The PLC controller automatically adjusts the extrusion speed, the mixer speed, the return powder feed rate and the drying air temperature and speed according to the set values.

7. The continuous preparation method of wet chicken manure dispersed particles according to claim 6, characterized in that, In step (2), the moisture content of the dried chicken manure powder is ≤12% and the fineness is ≤2mm.

8. The continuous preparation method of wet chicken manure dispersed particles according to claim 6, characterized in that, In step (3), the uniformly moistened zone after each drying zone is a non-heated turning zone, and the dwell time is 5-10 minutes.

9. The continuous preparation method of wet chicken manure dispersed particles according to claim 6, characterized in that, In step (4), large particles with a diameter >6mm are crushed and returned to the extruder in step (1) or used as recycled powder.

10. The continuous preparation method of wet chicken manure dispersed particles according to claim 6, characterized in that, In step (5), the PLC controller has three control loops: coating quality loop, which adjusts the speed of the return powder feeding screw according to the humidity sensor signal in the mixer; drying permeability loop, which increases the speed of the mixer or increases the return powder ratio when the pressure difference is higher than the set value according to the bed pressure difference sensor signal; and finished product moisture loop, which adjusts the mesh belt speed or the final air temperature according to the moisture content sensor signal at the dryer outlet.

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