A method for compound crushing and granulation of crop and vegetable straw

Abstract

This invention discloses a method for compound crushing and pelletizing of crop and vegetable straw, belonging to the field of biomass resource utilization technology. This method addresses the problems of coarse raw material processing and poor pellet quality stability in existing straw pelleting processes. Through a step-by-step process of coarse crushing, fine powdering, blending and conditioning, and conveying pelleting, it achieves refined processing of crop and vegetable straw. Simultaneously, it selectively adds 1%–10% waste wood powder based on the moisture content of the straw powder, flexibly controlling the calorific value, hardness, and molding performance of the pellets. This invention improves the adaptability of straw raw materials, significantly enhances the quality stability of finished pellets, realizes the efficient resource utilization of various straws, reduces resource waste and environmental pollution, and the prepared composite pellets can be directly used as biomass fuel or biomass-based raw material.

Description

Technical Field

[0001] This invention relates to the field of biomass resource utilization technology, specifically to a method for compound crushing and granulation of crop and vegetable straw. Background Technology

[0002] Crop straw is an important byproduct of agricultural production, characterized by its large yield and wide distribution. Common crops such as wheat, rice, corn, peanuts, soybeans, and cotton all produce large amounts of straw, while vegetable cultivation also generates various types of vegetable straw waste. Currently, most of these straw resources are either directly burned or discarded at will, which not only causes serious waste of biomass resources but also easily leads to environmental problems such as air pollution and soil degradation.

[0003] Processing straw into pellet fuel or biomass-based raw materials is an important way to realize the resource utilization of straw, which can alleviate the shortage of fossil energy and reduce the environmental impact of agricultural waste. However, the existing straw pellet preparation process still has many shortcomings. In the raw material processing stage, there is a lack of standardized crushing methods for different crop straws, resulting in low precision in raw material processing and insufficient crushing of straw fiber structure, which affects the subsequent pelleting effect. In terms of pellet quality control, it is impossible to flexibly adjust the preparation parameters according to the moisture characteristics of the straw itself. When the straw moisture content is high, the prepared pellets are prone to problems such as insufficient calorific value, low hardness, poor formability, and poor combustion stability, resulting in poor quality stability of the finished pellets and making it difficult to meet the needs of practical applications.

[0004] Therefore, developing a straw composite crushing and granulation method that can achieve refined straw processing and flexibly control pellet quality has become the key to solving the current problem of straw resource utilization. Summary of the Invention

[0005] The purpose of this invention is to provide a method for compound crushing and granulation of crop and vegetable straw.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for compound crushing and granulation of crop and vegetable straw includes the following steps: 1. Coarse Crushing Process: Using various crop straws and vegetable straws as raw materials, obvious impurities such as stones, plastics, and metals are removed manually or mechanically to prevent damage to subsequent processing equipment and affect particle quality. The straw raw materials after impurity removal are fed into a straw chopper, where the straw is coarsely crushed into segments of 3-5 cm in length by the shearing action of the straw chopper. This length setting ensures the uniformity of crushing in subsequent fine powder processing, while also ensuring smooth feeding of the equipment and avoiding material blockage problems.

[0007] 2. Fine powder processing: The coarsely crushed segmented material is directly fed into a hammer mill for secondary crushing. The high-speed impact and shearing action of the hammers fully breaks down the fiber structure of the straw, turning the material into powder. This significantly improves the mixing uniformity and subsequent extrusion molding performance of the material, laying the raw material foundation for the preparation of high-quality granules.

[0008] 3. Blending and Conditioning: The moisture content of the straw powder is monitored in real time using an online moisture meter. Waste wood powder is selectively added based on the measured moisture data. When the moisture content of the straw powder is high, waste wood powder is added for conditioning. The amount of wood powder added is controlled to 1%–10% of the total mass of the straw powder. Waste wood powder can effectively compensate for the insufficient calorific value of high-moisture straw raw materials, while improving the material's bonding and molding properties, and increasing the density, hardness, and combustion stability of the final granules. When the moisture content of the straw powder is within a suitable range, waste wood powder can be added without further addition, and subsequent granulation steps can be carried out directly.

[0009] 4. Conveying and pelletizing: The blended and conditioned mixture is conveyed to the pellet mill through a closed conveying pipeline. The closed conveying pipeline can be a screw conveyor or a pneumatic conveyor, which can realize continuous, dust-free, and quantitative feeding of the mixture, avoiding dust pollution and raw material loss during the material transportation process. After the mixture enters the pellet mill, it is extruded to obtain straw composite pellets. These pellets can be directly used as biomass fuel for combustion, heating, power generation, etc., or as biomass-based raw materials for subsequent deep processing.

[0010] In this invention, the crop straw includes one or more of wheat, rice, corn, peanut, soybean, and cotton straw, which can realize the comprehensive utilization of various agricultural straw wastes and expand the source of raw materials.

[0011] The beneficial effects of this invention are as follows: 1. This application adopts a graded crushing process of coarse crushing + fine powder to refine the straw raw material. First, the straw is cut into segments of fixed length, and then a secondary fiber crushing is carried out. This solves the problem of coarse raw material processing in existing processes, significantly improves the compatibility of straw raw material with pelleting process, and ensures the subsequent molding effect.

[0012] 2. This invention selectively adds waste wood powder based on the moisture content of straw powder, and precisely controls the amount of wood powder added to 1%–10%, which can flexibly adjust the calorific value, hardness, density and combustion stability of the pellets, effectively solving the problem of poor pellet quality of high-moisture straw and greatly improving the quality stability of the finished pellets.

[0013] 3. This invention can process various crop straws such as wheat and rice, as well as various vegetable straws. At the same time, the addition of waste wood powder realizes the synergistic utilization of wood waste, further improving the utilization rate of biomass resources, reducing the random disposal and burning of agricultural and forestry waste, and reducing resource waste and environmental pollution.

[0014] 4. The process steps of this invention are simple and easy to operate. The equipment selected are all conventional equipment in the field of biomass processing. There is no need for large-scale modification of existing production lines. The production cost is low. The feeding and conveying links adopt a closed design, which eliminates dust pollution. The production process is more environmentally friendly and suitable for large-scale industrial promotion and application. Detailed Implementation

[0015] The specific embodiments of the present invention will be described in further detail below with reference to the examples. These examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0016] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field; unless otherwise specified, the reagents or materials described are all from commercial sources. Example

[0017] A method for compound crushing and granulation of crop and vegetable straw includes the following steps: 1. Coarse crushing: Using wheat straw and cucumber straw as raw materials, after removing stones and plastic impurities from the raw materials, they are fed into a straw chopper to be coarsely crushed into segments with a length of 3 cm. 2. Fine powder processing: The segmented material is fed into a hammer mill for secondary crushing to break the fiber structure and obtain powdered material; 3. Blending and conditioning: The moisture content of the straw powder was found to be 25% by online testing. 1% of the total mass of the straw powder was added to waste wood powder and mixed evenly to obtain the conditioned mixture. 4. Conveying and pelletizing: The conditioned mixture is continuously, dust-free and quantitatively fed into the pellet manufacturing machine through a screw conveyor pipe. The mixture is then extruded to obtain straw composite pellets, which are used as biomass fuel with a calorific value of 18 MJ / kg and a pellet hardness of 120 N. Example

[0018] A method for compound crushing and granulation of crop and vegetable straw includes the following steps: 1. Coarse crushing: Using rice, corn, and tomato straw as raw materials, after removing impurities, the straw is fed into a straw cutter and coarsely crushed into segments with a length of 4 cm. 2. Fine powder processing: The segmented material is fed into a hammer mill for secondary crushing to obtain powdered material; 3. Blending and conditioning: The moisture content of the straw powder was found to be 30% by online testing. 5% of the total mass of the straw powder was added to waste wood powder and mixed evenly to obtain the conditioned mixture. 4. Conveying and pelletizing: The conditioned mixture is fed into the pellet mill through a pneumatic conveying pipeline and extruded to obtain straw composite pellets. These pellets are used as biomass fuel with a calorific value of 20 MJ / kg and a pellet hardness of 150 N. Example

[0019] A method for compound crushing and granulation of crop and vegetable straw includes the following steps: 1. Coarse crushing: Using peanut, soybean, and celery stalks as raw materials, after removing impurities, they are fed into a chaff cutter to coarsely crush them into segments of 5 cm in length; 2. Fine powder processing: The segmented material is fed into a hammer mill for secondary crushing to obtain powdered material; 3. Blending and conditioning: The moisture content of the straw powder was found to be 35% by online testing. 10% of the total mass of the straw powder was added to waste wood powder and mixed evenly to obtain the conditioned mixture. 4. Conveying and pelletizing: The conditioned mixture is fed into the pellet mill through a screw conveyor pipe and extruded to obtain straw composite pellets. These pellets are used as biomass-based raw materials, with a pellet density of 1.2 g / cm³ and a forming rate of 98%. Example

[0020] A method for compound crushing and granulation of crop and vegetable straw includes the following steps: 1. Coarse crushing: Using cotton and eggplant stalks as raw materials, after removing impurities, they are fed into a chaff cutter to be coarsely crushed into segments with a length of 3.5 cm. 2. Fine powder processing: The segmented material is fed into a hammer mill for secondary crushing to obtain powdered material; 3. Blending and conditioning: Online detection shows that the moisture content of the straw powder is 18%, eliminating the need to add waste wood powder and directly obtaining the conditioned mixture; 4. Conveying and pelletizing: The conditioned mixture is fed into the pellet mill through a pneumatic conveying pipeline and extruded to obtain straw composite pellets. These pellets are used as biomass fuel with a calorific value of 22 MJ / kg and a pellet hardness of 160 N.

[0021] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0022] 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.

[0023] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for compound crushing and granulation of crop and vegetable straw, characterized in that, Includes the following steps: S1. Coarse crushing: Using various crop straws and vegetable straws as raw materials, after removing obvious impurities, they are fed into a straw cutter and coarsely crushed into segments of 3-5 cm in length. S2. Fine powder treatment: The segmented material obtained in step S1 is fed into a hammer mill for secondary crushing to break the fiber structure and obtain powdered material. S3. Blending and conditioning: The moisture content of the straw powder obtained in step S2 is detected online. Waste wood powder is selectively added according to the humidity. The amount of wood powder added is 1%–10% of the total mass of the straw powder. The mixture is mixed evenly to obtain the conditioned mixture. S4. Conveying and granulating: The conditioned mixture obtained in step S3 is continuously, dust-free and quantitatively fed into the pellet manufacturing machine through a closed conveying pipeline, and straw composite pellets are obtained by extrusion molding.

2. The method for compound crushing and granulation of crop and vegetable straw according to claim 1, characterized in that, The crop straw mentioned in step S1 includes one or more of the following: wheat, rice, corn, peanut, soybean, and cotton straw.

3. The method for compound crushing and granulation of crop and vegetable straw according to claim 1, characterized in that, The sealed conveying pipeline mentioned in step S4 is either a spiral conveying pipeline or a pneumatic conveying pipeline.

4. The method for compound crushing and granulation of crop and vegetable straw according to claim 1, characterized in that, The straw composite pellets can be used directly as biomass fuel or biomass-based raw materials.