Formula and preparation process of high-calorific-value leaf walnut shell composite bio-particle
Through scientific formulation and process, high-calorific-value biomass pellets are prepared from solid wood sawdust, walnut shells, barley straw, and leaves. This solves the problems of low calorific value and high ash content in biomass pellets, realizing the resource utilization and environmental benefits of agricultural and forestry waste, and is suitable for industrial and civilian applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-03-11
- Publication Date
- 2026-07-03
Smart Images
Figure CN122326299A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of composite biological particles, specifically to the formulation and preparation process of high-calorific-value leaf and walnut shell composite biological particles. Background Technology
[0002] With the depletion of fossil fuels and tightening environmental policies, biomass energy, as a clean and renewable energy source, has become an important direction for energy structure transformation. Biomass pellets, in particular, are widely used in industrial and civilian sectors due to their convenient storage and transportation and stable combustion. However, existing biomass pellet production often uses single or simple mixed raw materials, resulting in significant drawbacks: when using straw or common leaves as the main raw materials, the calorific value of the product is generally below 18 MJ / kg, making it difficult to meet the requirements for efficient combustion; using pure wood chips as raw materials leads to high costs and limited resource supply. Meanwhile, my country generates a huge amount of agricultural and forestry waste annually, producing large quantities of sawdust, walnut shells, barley straw, and leaves. Most of this waste is discarded or burned indiscriminately, causing resource waste and environmental problems such as air pollution. Furthermore, existing biomass pellet production processes often result in excessively high ash content (generally exceeding 3%) due to improper raw material processing, leading to significant combustion pollution, poor formability, and brittleness.
[0003] Therefore, developing a composite biomass pellet formulation and preparation process that uses diverse agricultural and forestry wastes as raw materials and possesses high calorific value, low ash content, and excellent formability is of great significance for promoting the industrialization of biomass energy. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to overcome the defects of the above-mentioned technologies and provide a formula and preparation process for high-calorific-value leaf and walnut shell composite bio-particles.
[0005] To solve the above-mentioned technical problems, the present invention provides a formula and preparation process for high-calorific-value leaf and walnut shell composite bio-particles: The formula for high-calorific-value leaf and walnut shell composite bio-particles consists of solid wood sawdust, walnut shells, barley straw, and leaves, with each component by mass percentage as follows: solid wood sawdust 40%, walnut shells 45%, barley straw 10%, and leaves 5%; the low calorific value of the high-calorific-value leaf and walnut shell composite bio-particles is 20.8 MJ / kg, with a basic ash content of 1.93%, dry ash-free volatile matter of 78.15%, basic carbon of 45.50%, basic hydrogen of 4.49%, basic nitrogen of 0.46%, basic sulfur of 0.05%, and basic oxygen of 43.28%.
[0006] A preparation process for high-calorific-value leaf and walnut shell composite bio-particles, the preparation process comprising the following steps:
[0007] Step 1: Raw material pretreatment. The solid wood sawdust, barley straw and leaves are sliced using a slicer to obtain sliced solid wood sawdust, sliced barley straw and sliced leaves.
[0008] Step 2: Drying treatment. The sliced solid wood sawdust, the sliced barley straw, and the sliced leaves are fed into a dryer for drying treatment to obtain dried solid wood sawdust, dried barley straw, and dried leaves.
[0009] Step 3: Coarse crushing and sieving. The dried solid wood sawdust, the dried barley straw, and the dried leaves are fed into a crusher for coarse crushing to obtain a coarsely crushed mixed raw material. The coarsely crushed mixed raw material is then sieved through a vibrating screen to separate the sand and soil from the coarsely crushed mixed raw material, resulting in a cleaned mixed raw material.
[0010] Step 4: Walnut shell processing and fine grinding. The walnut shells are fed separately into a grinder for grinding to obtain ground walnut shells. The impurity-removed mixed raw materials are mixed and stirred evenly with the ground walnut shells to obtain mixed raw materials. The mixed raw materials are then fed into a grinder for fine grinding to obtain finely ground composite raw materials.
[0011] Step 5: Granulation and forming. The finely pulverized composite raw material is fed into a pellet mill for granulation to obtain the high-calorific-value leaf and walnut shell composite biological pellets. The specifications of the high-calorific-value leaf and walnut shell composite biological pellets are 5cm in length and 1cm in diameter.
[0012] As an improvement, the drying temperature of the dryer in step 2 is 80-120℃, and the moisture content of the dried solid wood sawdust, the dried highland barley straw and the dried leaves are all controlled at 8%-12%.
[0013] As an improvement, the particle size of the mixed raw material after coarse crushing in step 3 is 20-40 mesh, and the particle size of the composite raw material after fine crushing in step 4 is 60-80 mesh.
[0014] As an improvement, the mixing speed in step 4 is 150-200 r / min, and the mixing time is 10-15 min, to ensure that the impurity-removed mixed raw materials are evenly mixed with the crushed walnut shells.
[0015] As an improvement, in step 5, the ring die compression ratio of the pellet mill is 1:8-1:10, and the pelleting temperature is 100-120℃, to ensure that the finely pulverized composite raw material is stable in shape.
[0016] As an improvement, the screen aperture of the gyratory screen in step 3 is 0.5-1mm, which effectively separates sand and impurities from the coarsely crushed mixed raw materials.
[0017] The advantages of this invention compared to existing technologies are as follows: First, it realizes the resource utilization of agricultural and forestry waste, transforming solid wood sawdust, walnut shells, barley straw, leaves, and other agricultural and forestry waste into renewable energy, solving the problems of pollution and waste, and conforming to the concept of green development. Second, the formula is scientific, using 45% walnut shells and 40% solid wood sawdust as the core high-calorific-value components, combined with 10% barley straw and 5% leaves. The barley straw enhances the formability, while the leaves adjust costs. The final product has a lower heating value of 20.8 MJ / kg (approximately 5000 kcal / kg), basic sulfur of 0.05%, and basic ash of 1.93%, exhibiting excellent performance. Third, the process is simple and suitable for industrialization, including five core steps such as raw material pretreatment. Parameters such as the slice thickness of 2-5 mm are clearly defined, and the slicers and pelletizers used are all conventional equipment, resulting in low cost and easy mass production. Fourth, the product has wide applications and high economic and environmental value. Its specifications are 5cm in length and 1cm in diameter. It can replace coal and be used in industrial and civil fields. Its cost is lower than fossil fuels and high-quality pellets, which is in line with environmental protection policies and has great potential for promotion. Attached Figure Description
[0018] Figure 1 This is a formula diagram of the high-calorific-value leaf and walnut shell composite biological particles of the present invention.
[0019] Figure 2 This is a process diagram of the preparation of the high-calorific-value leaf and walnut shell composite bioparticles of the present invention. Detailed Implementation
[0020] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.
[0021] Referring to the attached figures, the formulation and preparation process of high-calorific-value leaf and walnut shell composite bio-granules are described. The formulation consists of solid wood sawdust, walnut shells, barley straw, and leaves, with the following mass percentages: solid wood sawdust 40%, walnut shells 45%, barley straw 10%, and leaves 5%. The low calorific value of the high-calorific-value leaf and walnut shell composite bio-granules is 20.8 MJ / kg, with a basic ash content of 1.93%, dry ash-free volatile matter of 78.15%, basic carbon of 45.50%, basic hydrogen of 4.49%, basic nitrogen of 0.46%, basic sulfur of 0.05%, and basic oxygen of 43.28%.
[0022] A preparation process for high-calorific-value leaf and walnut shell composite bio-particles, the preparation process comprising the following steps:
[0023] Step 1: Raw material pretreatment. The solid wood sawdust, barley straw and leaves are sliced using a slicer to obtain sliced solid wood sawdust, sliced barley straw and sliced leaves.
[0024] Step 2: Drying treatment. The sliced solid wood sawdust, the sliced barley straw, and the sliced leaves are fed into a dryer for drying treatment to obtain dried solid wood sawdust, dried barley straw, and dried leaves.
[0025] Step 3: Coarse crushing and sieving. The dried solid wood sawdust, the dried barley straw, and the dried leaves are fed into a crusher for coarse crushing to obtain a coarsely crushed mixed raw material. The coarsely crushed mixed raw material is then sieved through a vibrating screen to separate the sand and soil from the coarsely crushed mixed raw material, resulting in a cleaned mixed raw material.
[0026] Step 4: Walnut shell processing and fine grinding. The walnut shells are fed separately into a grinder for grinding to obtain ground walnut shells. The impurity-removed mixed raw materials are mixed and stirred evenly with the ground walnut shells to obtain mixed raw materials. The mixed raw materials are then fed into a grinder for fine grinding to obtain finely ground composite raw materials.
[0027] Step 5: Granulation and forming. The finely pulverized composite raw material is fed into a pellet mill for granulation to obtain the high-calorific-value leaf and walnut shell composite biological pellets. The specifications of the high-calorific-value leaf and walnut shell composite biological pellets are 5cm in length and 1cm in diameter.
[0028] In step 2, the drying temperature of the dryer is 80-120℃, and the moisture content of the dried solid wood sawdust, the dried highland barley straw, and the dried leaves are all controlled at 8%-12%.
[0029] The particle size of the mixed raw material after coarse crushing in step 3 is 20-40 mesh, and the particle size of the composite raw material after fine crushing in step 4 is 60-80 mesh.
[0030] In step 4, the mixing speed is 150-200 r / min and the mixing time is 10-15 min to ensure that the impurity-removed mixed raw materials are evenly mixed with the crushed walnut shells.
[0031] In step 5, the ring die compression ratio of the pellet mill is 1:8-1:10, and the pelleting temperature is 100-120℃ to ensure the stable molding of the finely pulverized composite raw material.
[0032] In step 3, the screen aperture of the gyratory screen is 0.5-1mm, which effectively separates sand and impurities from the coarsely crushed mixed raw materials.
[0033] This invention discloses the formulation and preparation process of high-calorific-value tree leaf and walnut shell composite biomass pellets, aiming to solve the problems of low calorific value, high ash content, and insufficient utilization rate of agricultural and forestry waste in existing biomass pellets. The technical solution of this invention is described in detail below with reference to specific embodiments. These embodiments are only some preferred embodiments of this invention and are not intended to limit the scope of protection of this invention.
[0034] Raw material selection and formulation ratio:
[0035] The raw materials used in this invention are all agricultural and forestry waste, which are widely available and inexpensive, thus achieving resource recycling and reducing environmental pollution. The selection criteria for each raw material are as follows: solid wood sawdust is selected from sawdust produced during hardwood processing to avoid mixing with bark, metal impurities, etc.; walnut shells are selected from dried walnut shells that are free from mold and insect infestation, as they have high density and high calorific value, making them the core raw material for improving the calorific value of composite bio-particles; barley straw is selected from mature harvested and dried straw, with soil and dead leaves removed from the roots; and broad-leaved leaves that naturally fall in autumn are selected and dried until the moisture content is below 20% before use.
[0036] The core formula of this invention is precisely proportioned by weight percentage, specifically: 40% solid wood sawdust, 45% walnut shells, 10% highland barley straw, and 5% tree leaves. This proportion was determined based on extensive experimental verification. Walnut shells and solid wood sawdust, as high-calorific-value components, together account for 85%, providing the basic calorific value for the pellets. The fibrous structure of highland barley straw enhances pellet formation, while tree leaves serve as an auxiliary component to adjust raw material costs. To ensure accurate proportioning, electronic scales are used to weigh each raw material in actual production, with weighing accuracy controlled within ±0.5%.
[0037] The mass percentages of each component in the formula satisfy the following relationship: Let the mass of solid wood sawdust be m1, the mass of walnut shells be m2, the mass of highland barley straw be m3, and the mass of leaves be m4. Then the formulas for calculating the mass percentages ω1, ω2, ω3, and ω4 of each component are:
[0038] , , ,
[0039] In the above formula, ω1 represents the mass percentage of solid wood sawdust, ω2 represents the mass percentage of walnut shells, ω3 represents the mass percentage of highland barley straw, and ω4 represents the mass percentage of leaves; m1 to m4 correspond to the actual weighed mass of each component. The purpose of this formula is to ensure that the raw materials are mixed in the preset proportions, avoiding a decrease in product properties such as calorific value and formability due to deviations in the proportions. For example, if the proportion of walnut shells is less than 45%, the lower heating value of the pellets may not meet the design requirement of 20.8 MJ / kg.
[0040] Detailed preparation process steps:
[0041] The preparation process of this invention includes five core steps in sequence: raw material pretreatment, drying treatment, coarse crushing and sieving, walnut shell treatment and mixed fine crushing, and granulation. Each step is closely connected, and the process parameters of each step have been optimized to ensure the stable performance of the final product.
[0042] Step 1: Raw material pretreatment:
[0043] The purpose of raw material pretreatment is to process solid wood sawdust, barley straw, and leaves into forms that facilitate subsequent drying and pulverization. The specific operation is as follows: Select qualified solid wood sawdust, barley straw, and leaves are fed into a slicer for slicing. Barley straw, due to its longer length, needs to be cut into 10-15cm segments before being fed into the slicer; leaves can be fed in batches directly. The slicer's blade speed is set to 300 rpm, and the slice thickness is controlled at 2-5mm, ultimately yielding sliced solid wood sawdust, sliced barley straw, and sliced leaves. This step uniformly forms the raw materials into smaller flake structures, increasing the heat-receiving area during subsequent drying and preventing blockages in the pulverizer.
[0044] Step 2: Drying process:
[0045] Drying is a crucial step in reducing the moisture content of raw materials. Excessive moisture content leads to difficulties in subsequent grinding, poor pelleting, and a decrease in the calorific value of the final product. The chopped sawdust, chopped barley straw, and chopped leaves obtained in step 1 are fed together into a continuous dryer. The dryer's drying temperature is set at 80-120℃, and the drying time is adjusted according to the initial moisture content of the raw materials, generally 30-60 minutes.
[0046] The formula for calculating the moisture content of raw materials during the drying process is: wet-dry-wet The formula is used to monitor the drying effect in real time, ensuring that the moisture content of the wood sawdust, barley straw, and leaves is controlled between 8% and 12% after drying. If the moisture content is higher than 12%, the drying time needs to be extended or the drying temperature increased; if the moisture content is lower than 8%, the raw materials are easily broken, affecting the uniformity of subsequent mixing. In this case, a small amount of water can be added appropriately for adjustment.
[0047] Step 3: Coarse crushing and sieving:
[0048] The purpose of coarse crushing is to break the dried raw materials into smaller particles, preparing them for subsequent fine crushing. The dried sawdust, dried barley straw, and dried leaves from step 2 are fed into a hammer mill for coarse crushing. The mill's screen aperture is set to 5mm, and the crushing time is 5-8 minutes, resulting in a coarsely crushed mixed raw material with a particle size controlled between 20-40 mesh. Particle size is an important indicator of crushing efficiency and can be measured using a standard sieve. A particle size of 20-40 mesh means that the raw material particles can pass through a 20-mesh standard sieve but not a 40-mesh standard sieve. This particle size range facilitates subsequent sieving and impurity removal while ensuring the efficiency of subsequent fine crushing.
[0049] After coarse crushing, the mixture needs to be screened to remove impurities. The coarsely crushed mixture is fed into a vibrating screen with a mesh size of 0.5-1 mm, a vibration amplitude of 5-8 mm, and a frequency of 150 times / min. Through the vibration of the vibrating screen, impurities such as sand and small stones, due to their higher density and finer particles, will be separated from the mixture, resulting in a cleaned mixture. The impurity content after screening must be controlled below 0.1%. The formula for calculating the impurity content is: (Impurity content = Coarse Crusher / Coarse Crusher) = Coarse Crusher / Coarse Crusher Where Z represents the impurity content, m represents the mass of the separated impurities, and m represents the mass of the mixed raw material after coarse crushing. This formula is used to evaluate the screening effect. Excessive impurity content will lead to an increase in the ash content of the final product, affecting combustion performance.
[0050] Step 4: Walnut shell processing and fine grinding:
[0051] Walnut shells are quite hard, and if coarsely ground together with other raw materials, uneven grinding can easily occur. Therefore, they need to be ground separately. Select qualified walnut shells and feed them into a dedicated nut shell grinder. The grinder's blade speed is 500 rpm, and the grinding time is 10-12 minutes. The resulting ground walnut shells have a particle size that is basically the same as the coarsely ground mixed materials, which facilitates uniform mixing in subsequent processes.
[0052] The purified raw materials obtained in step 3 are fed together with the crushed walnut shells into a double-helix mixer for mixing. The mixing speed is set to 150-200 r / min, and the mixing time is 10-15 min. Uniform mixing is crucial for ensuring stable product performance and can be verified through random sampling. Specifically, 3-5 samples from different locations are selected from the mixed raw materials, and the walnut shell content in each sample is measured. If the deviation in walnut shell content among the samples does not exceed ±1%, the mixture is considered uniform, and the mixed raw materials are obtained.
[0053] After mixing, the mixed raw materials are fed into an air jet mill for fine pulverization. The inlet pressure of the air jet mill is set to 0.8 MPa, and the pulverization time is 15-20 minutes, resulting in a finely pulverized composite material with a particle size controlled at 60-80 mesh. Fine pulverization results in finer particle sizes and a larger contact area between particles. During subsequent granulation, lignin and other binding components in the raw material are more easily released under temperature and pressure, enhancing the granulation strength. The particle size detection method after fine pulverization is the same as after coarse pulverization, ensuring compliance with the 60-80 mesh requirement.
[0054] Step 5: Granulation and molding:
[0055] Granulation is the process of processing finely pulverized composite raw materials into particles of specific dimensions, directly affecting the appearance, strength, and calorific value of the product. The finely pulverized composite raw material obtained in step 4 is fed into a ring die pellet mill for pelletizing. The ring die compression ratio of the pellet mill is set to 1:8-1:10, the pelletizing temperature is set to 100-120℃, and the feeding speed is 50-80 kg / h. The ring die compression ratio refers to the ratio of the effective length of the ring die hole to the hole diameter. The higher this ratio, the higher the density and strength of the particles. Excessive pelletizing temperature leads to the loss of calorific value components in the raw material, while insufficient temperature results in insufficient lignin precipitation, affecting the pelletizing effect.
[0056] Through the extrusion action of a pellet mill, the finely pulverized composite raw materials are pressed into the ring die holes to form continuous columnar particles. These particles are then cut by a cutter to obtain high-calorific-value leaf and walnut shell composite bio-particles with a length of 5 cm and a diameter of 1 cm. The particle length can be controlled by adjusting the cutter's rotation speed. The relationship between the cutter's rotation speed and the particle length satisfies the following: Where L represents the particle length, v represents the extrusion speed of the raw material, n represents the cutter speed, and d represents the particle diameter. This formula guides the setting of the cutter speed to ensure that the particle length meets the design requirements. The granulated particles need to be cooled to room temperature before packaging and storage.
[0057] Product performance testing and results:
[0058] The performance of the high-calorific-value leaf and walnut shell composite bioparticles prepared in this embodiment was tested, and the results are as follows:
[0059] Elemental composition: basic carbon (Car) 45.50%, basic hydrogen (Har) 4.49%, basic nitrogen (Nar) 0.46%, basic sulfur (Sar) 0.05%, basic oxygen (Oar) 43.28%; among which, the basic sulfur content is only 0.05%, which is far below the national standard limit of 0.3%, and very few sulfides are produced during combustion, making it environmentally friendly.
[0060] Ash and volatile matter: Basic ash (Aar) 1.93%, lower than the 3% ash standard for high-quality biomass pellets, resulting in less ash residue after combustion and reducing cleaning workload; Dry ash-free basic volatile matter (Vdaf) 78.15%, the high volatile matter content makes the pellets easy to ignite and burn quickly.
[0061] Calorific value: The lower heating value (Qnet,v,ar) is 20.8 MJ / kg. According to the conversion relationship of calorific units, 1 MJ = 238.85 kcal, therefore the lower heating value is converted to: With a calorific value of kcal / kg, it meets the requirements for high-calorific-value biomass pellets and can replace fossil fuels such as coal in industrial boilers, residential heating, and other fields.
[0062] The beneficial effects of this technical solution are:
[0063] This technology achieves efficient resource utilization of agricultural and forestry waste, with significant environmental value: The sawdust, walnut shells, barley straw, and leaves used in this technical solution are all waste products generated during agricultural and forestry production and processing. If these wastes are arbitrarily dumped, they can easily cause environmental pollution; if incinerated, they waste energy and produce harmful gases. This technical solution uses these four types of agricultural and forestry waste as raw materials to prepare high-calorific-value leaf and walnut shell composite bio-granules. This not only completely solves the problem of waste disposal but also transforms them into usable renewable energy, achieving resource recycling, conforming to the concept of green development, and possessing significant environmental and resource-saving benefits.
[0064] The scientifically formulated recipe ensures high calorific value and excellent combustion performance: This technical solution uses walnut shells (45%) and solid wood sawdust (40%) as the core high-calorific-value components. Both raw materials are inherently dense and have high calorific value, and their combined 85% proportion provides a solid calorific value foundation for the high-calorific-value leaf and walnut shell composite bio-granules. The addition of 10% barley straw and 5% leaves enhances pellet formation due to the fiber structure of the barley straw, while the leaves adjust raw material costs without affecting the core performance of the product. The final high-calorific-value leaf and walnut shell composite bio-granules achieve a lower heating value of 20.8 MJ / kg (approximately 5000 kcal / kg), a basic sulfur content of only 0.05%, a basic ash content of only 1.93%, and a dry ash-free volatile matter content of 78.15%. This not only meets the high calorific value requirement but also possesses excellent combustion performance with low pollution and easy combustion, far exceeding that of ordinary biomass pellet products.
[0065] The preparation process is simple and efficient, suitable for industrial production: This technical solution's preparation process includes only five core steps: raw material pretreatment, drying, coarse crushing and sieving, walnut shell processing and fine crushing, and pelleting. The process is concise and the steps are closely linked. The process clearly defines key indicators such as slice thickness, drying temperature, crushing particle size, mixing speed, and pelleting parameters. For example, slice thickness is controlled at 2-5mm, the moisture content of the raw material after drying is controlled at 8%-12%, and the particle size of the raw material after fine crushing is controlled at 60-80 mesh. These precise parameter settings ensure the stability and controllability of the production process. Furthermore, the equipment used in the process, such as slicers, dryers, crushers, gyratory screens, and pellet mills, are all conventional equipment in the biomass processing field, requiring no specialized customized equipment. This results in low equipment investment costs and facilitates rapid industrial-scale mass production for enterprises.
[0066] The product has a wide range of applications and significant economic value: The high-calorific-value leaf and walnut shell composite biomass pellets prepared by this technology have uniform specifications (5cm in length and 1cm in diameter), excellent combustion performance, and can directly replace traditional fossil fuels such as coal. They are widely used in various fields such as industrial boiler heating, residential heating, and agricultural greenhouse insulation. The raw materials are all low-cost agricultural and forestry waste, and the production process costs are controllable, making the overall product cost lower than coal and high-quality biomass pellets. While possessing environmental advantages, it also has strong market competitiveness, bringing considerable economic benefits to production enterprises and reducing energy costs for users.
[0067] The product boasts excellent environmental performance and aligns with environmental policy guidelines: the high-calorific-value tree leaf and walnut shell composite bio-particles prepared using this technology have a base sulfur content of only 0.05%, far below the 0.3% limit in the national standard "Biomass Solid Molding Fuel" (GB / T 31743-2015). This results in minimal production of harmful gases such as sulfides during combustion; the base ash content is only 1.93%, leading to low ash emissions and subsequent cleanup costs. These low-pollution characteristics perfectly match my country's current policy requirements for clean energy, effectively reducing environmental pollution during energy use and contributing to the achievement of "carbon peaking and carbon neutrality" goals, demonstrating significant market potential.
[0068] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.
Claims
1. A formulation for high-calorific-value tree leaf and walnut shell composite bio-granules, characterized in that: The formula consists of solid wood sawdust, walnut shells, barley straw, and leaves. The components, by mass percentage, are: solid wood sawdust 40%, walnut shells 45%, barley straw 10%, and leaves 5%. The low calorific value of the high-calorific-value leaf and walnut shell composite bio-particles is 20.8 MJ / kg, with a basic ash content of 1.93%, dry ash-free volatile matter of 78.15%, basic carbon of 45.50%, basic hydrogen of 4.49%, basic nitrogen of 0.46%, basic sulfur of 0.05%, and basic oxygen of 43.28%.
2. A preparation process for high-calorific-value leaf and walnut shell composite bio-particles, characterized in that: The preparation process includes the following steps: Step 1: Raw material pretreatment. The solid wood sawdust, barley straw and leaves are sliced using a slicer to obtain sliced solid wood sawdust, sliced barley straw and sliced leaves. Step 2: Drying treatment. The sliced solid wood sawdust, the sliced barley straw, and the sliced leaves are fed into a dryer for drying treatment to obtain dried solid wood sawdust, dried barley straw, and dried leaves. Step 3: Coarse crushing and sieving. The dried solid wood sawdust, the dried barley straw, and the dried leaves are fed into a crusher for coarse crushing to obtain a coarsely crushed mixed raw material. The coarsely crushed mixed raw material is then sieved through a vibrating screen to separate the sand and soil from the coarsely crushed mixed raw material, resulting in a cleaned mixed raw material. Step 4: Walnut shell processing and fine grinding. The walnut shells are fed separately into a grinder for grinding to obtain ground walnut shells. The impurity-removed mixed raw materials are mixed and stirred evenly with the ground walnut shells to obtain mixed raw materials. The mixed raw materials are then fed into a grinder for fine grinding to obtain finely ground composite raw materials. Step 5: Granulation and forming. The finely pulverized composite raw material is fed into a pellet mill for granulation to obtain the high-calorific-value leaf and walnut shell composite biological pellets. The specifications of the high-calorific-value leaf and walnut shell composite biological pellets are 5cm in length and 1cm in diameter.
3. The preparation process of the high-calorific-value leaf and walnut shell composite bioparticles according to claim 2, characterized in that: In step 2, the drying temperature of the dryer is 80-120℃, and the moisture content of the dried solid wood sawdust, the dried highland barley straw, and the dried leaves are all controlled at 8%-12%.
4. The preparation process of the high-calorific-value leaf and walnut shell composite bioparticles according to claim 2, characterized in that: The particle size of the mixed raw material after coarse crushing in step 3 is 20-40 mesh, and the particle size of the composite raw material after fine crushing in step 4 is 60-80 mesh.
5. The preparation process of the high-calorific-value leaf and walnut shell composite bioparticles according to claim 2, characterized in that: In step 4, the mixing speed is 150-200 r / min and the mixing time is 10-15 min to ensure that the impurity-removed mixed raw materials are evenly mixed with the crushed walnut shells.
6. The preparation process of the high-calorific-value leaf and walnut shell composite bioparticles according to claim 2, characterized in that: In step 5, the ring die compression ratio of the pellet mill is 1:8-1:10, and the pelleting temperature is 100-120℃ to ensure the stable molding of the finely pulverized composite raw material.
7. The preparation process of high-calorific-value leaf and walnut shell composite bioparticles according to claim 2, characterized in that: In step 3, the screen aperture of the gyratory screen is 0.5-1mm, which effectively separates sand and impurities from the coarsely crushed mixed raw materials.