Biomass derived fuel based on other garbage and preparation method thereof

Abstract

The invention discloses a biomass derived fuel based on other garbage and a preparation method thereof.The preparation method comprises the steps that the other garbage obtained after household garbage classification serves as raw materials, and a base material meeting the biomass fuel preparation requirement is obtained through a multi-stage sorting and multi-stage crushing technology; the auxiliary materials such as the straw, the waste wood chips, the calcium hydroxide, the calcium oxide and the sodium silicate are added according to a scientific proportion, so that the calorific value of the fuel is remarkably increased, the ash content is reduced, and the generation and emission of pollutants such as SO2, HCl and dioxin are effectively inhibited. Equipment involved in the whole process is mature, large-scale production is easy to achieve, environmental protection and economic benefits are remarkable, and the method is particularly suitable for being applied and popularized in areas without waste incineration facilities.

Description

Technical Field

[0001] This invention relates to the field of environmental protection technology and solid waste resource utilization, specifically to a biomass-derived fuel prepared from other waste after household waste sorting, and a method for preparing the biomass-derived fuel. Background Technology

[0002] Household waste is classified into wet waste (kitchen waste), hazardous waste, recyclable waste, and other waste. With the full implementation of my country's waste sorting system, the coverage of waste sorting in cities at all levels is constantly expanding, and the proportion of other waste separated from urban household waste has significantly increased. Currently, the resource utilization of other waste mainly relies on processes such as incineration and pyrolysis to convert it into electrical or thermal energy (e.g., CN103712217B), thereby realizing energy recovery from waste.

[0003] However, existing technologies have significant limitations. First, traditional incineration technologies struggle to effectively separate impurities such as metals, glass, and chlorine-containing materials during the pretreatment stage, leading to decreased combustion quality and the emission of harmful gases such as sulfur dioxide (SO2) and hydrogen chloride (HCl). Although patents such as CN101949546B have proposed methods for treating dioxins and pollutants in incineration exhaust gases, they primarily focus on end-of-pipe treatment after incineration, failing to prevent chlorine-containing materials from entering the high-temperature incineration environment at the source. This not only increases the load, cost, and complexity of the exhaust gas purification system but also makes the control of highly toxic substances such as dioxins entirely dependent on complex and costly end-of-pipe processes, resulting in high operational risks and control difficulties.

[0004] Secondly, existing technologies for preparing fuel from waste still have shortcomings when processing other sorted waste. For example, CN119799384A discloses a method for producing biomass briquettes from municipal solid waste, which involves sorting waste using a drum screen and air classifier, and adding combustion-aiding components such as potassium nitrate and magnesium carbonate. This method can improve combustion performance, but its removal effect on harmful components is limited, and it cannot suppress the formation of acidic gases and dioxins.

[0005] In summary, existing technologies either suffer from insufficient sorting efficiency at the source or rely on complex end-of-pipe treatment, resulting in fuel products with high ash content, unstable calorific value, and difficulty in controlling combustion pollutants. This limits the economic and environmental viability of other waste resource recovery. Therefore, there is an urgent need to develop a new treatment technology capable of specifically controlling pollutant generation to achieve efficient and clean resource recovery of other waste. Summary of the Invention

[0006] The purpose of this invention is to provide a biomass-derived fuel based on other waste and its preparation method. The aim is to effectively remove impurities through multi-stage sorting and crushing processes, and to prepare a biomass-derived fuel with high calorific value, low ash content, and compliance with emission standards for harmful gases such as SO2, HCl and dioxins during combustion, thereby achieving efficient and clean resource utilization of other waste.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: The first aspect of this invention is to provide a method for preparing biomass-derived fuel based on other waste, the method comprising the following steps: The collected waste is subjected to gradient screening to separate materials with a particle size larger than the first pore size and materials with a particle size smaller than the second pore size, and materials with a particle size between the first pore size and the second pore size are collected. The collected materials are sheared and crushed to obtain primary shredded material; The primary shredded material is subjected to magnetic separation to remove metal impurities, followed by air separation and bouncing sieve separation to separate flexible and rigid materials; The flexible and rigid materials are finely crushed to obtain biomass substrate with a particle size of 3-5 mm; The biomass base material is mixed with auxiliary materials to obtain biomass-derived fuel.

[0008] A second aspect of the present invention is to provide a biomass-derived fuel based on other waste, comprising biomass base material and auxiliary materials.

[0009] Preferably, the biomass-derived fuel is prepared by the biomass-derived fuel preparation method based on other waste described in the first aspect of the present invention.

[0010] In a preferred embodiment, the step of gradient screening of the collected other waste includes: feeding the sorted other waste into a rotary drum screen via a feeder for gradient screening. For example, the rotary drum screen is formed by nesting a drum with a first aperture and a drum with a second aperture.

[0011] During the gradient screening process, materials larger than the first aperture are separated by the first aperture drum, materials smaller than the second aperture are separated by the second aperture drum, and materials between the first and second apertures are collected in the space between the first and second aperture drums.

[0012] In a preferred embodiment, the first aperture is preferably 65-90mm, such as 70mm, 75mm, 80mm, 85mm, etc.

[0013] In a preferred embodiment, the second aperture is preferably 25-50 mm, such as 30 mm, 35 mm, 40 mm, 45 mm, etc.

[0014] In a preferred embodiment, the difference between the first aperture and the second aperture is 30-50 mm, such as 33 mm, 35 mm, 38 mm, 40 mm, 42 mm, 45 mm, 48 mm, etc.

[0015] In a preferred embodiment, the shearing and crushing can be carried out by a shearing crusher, such as a twin-shaft or quad-shaft shearing crusher, especially a low-speed, high-torque shearing crusher. Specifically, the material with a particle size between the first and second aperture is fed into a low-speed, high-torque twin-shaft shearing crusher. The main shaft speed is controlled at 30–50 rpm, the shearing force is 80–120 kN, and the blade gap is set to 18–22 mm. The material passes through the crushing chamber once, with a residence time of approximately 10–15 seconds. After crushing, the particle size of the material is mainly distributed in the range of 15–45 mm, of which the proportion of particles with a diameter of 20–30 mm is not less than 70%.

[0016] In a preferred embodiment, during the air separation process, the airflow velocity is preferably 7.5-14 m / s, more preferably 8-13 m / s, and even more preferably 9-12 m / s.

[0017] In a preferred embodiment, during the wind selection process, the wind direction forms an angle of 10°-20° with the horizontal plane, preferably 12°-18°, and more preferably 14°-17°.

[0018] In a preferred embodiment, the bouncing sieving is performed using a bouncing screen with an amplitude of 3-5 mm, more preferably 3.5-4.5 mm.

[0019] In a preferred embodiment, the vibration frequency of the bouncing screen is 12-18Hz, more preferably 14-15Hz.

[0020] In a preferred embodiment, the tilt angle of the sieve plate of the bouncing sieve is 5°-15°, more preferably 8°-12°, and even more preferably 10°-11°.

[0021] In a preferred embodiment, the flexible material and the rigid material are separately and independently finely crushed into materials of 3-5 mm, and the crushed flexible material and the crushed rigid material are combined to obtain a biomass substrate with a particle size of 3-5 mm.

[0022] In a preferred embodiment, the flexible material can be crushed by a rotor crusher (such as a high-speed rotor crusher).

[0023] In a preferred embodiment, the rigid object can be crushed by a reversible hammer crusher (such as a reversible high-speed hammer crusher).

[0024] The above classification of flexible and rigid materials is based on their physical properties. Flexible materials refer to those carried away by the airflow during air separation; these materials are soft, easily bent, or torn, such as plastic films, fabrics, and paper. Rigid materials refer to those separated during bouncy screening based on the difference between their elasticity and rigidity; these materials are hard and not easily deformed, such as nut shells, hard plastics, and wood blocks.

[0025] In a preferred embodiment, the auxiliary materials include biomass fuel, calcium hydroxide, calcium oxide, and silicates.

[0026] In a preferred embodiment, the biomass fuel can be one or more of the leaves, flowers, stems, roots, and fruit shells of a plant. For example, it can be one or more of straw, sawdust, bark, sawdust, bagasse, rice husks, and nut shells, such as a combination of straw and sawdust.

[0027] In a preferred embodiment, the silicate may be one or more of sodium silicate, potassium silicate, calcium silicate, magnesium silicate, iron silicate, and aluminum silicate.

[0028] In a preferred embodiment, the biomass-derived fuel comprises the following components in parts by weight: Biomass substrate: 60-85 parts, preferably 65-80 parts, more preferably 68-75 parts, for example 68 parts, 70 parts, 72 parts, 75 parts; Biomass fuel: 15-35 parts, preferably 15-30 parts, more preferably 20-25 parts, for example 20 parts, 22 parts, 23 parts, 25 parts; Calcium hydroxide: 1-4 parts, preferably 1-3 parts, more preferably 1-2.5 parts, for example 1 part, 2 parts, 2.5 parts; Calcium oxide: 1-4 parts, preferably 1-3 parts, more preferably 1-2.5 parts, for example 1 part, 2 parts, 2.5 parts; Silicate: 0.5-3 parts, preferably 0.5-2 parts, more preferably 1-2 parts, for example 1 part, 1.5 parts, or 2 parts.

[0029] In a preferred embodiment, the method further includes drying the biomass-derived fuel to a moisture content of 10%-15%. More preferably, the dried biomass-derived fuel is pelletized to obtain biomass-derived pellet fuel.

[0030] In a preferred embodiment, the pelletizing process involves placing biomass-derived fuel, preferably dried biomass-derived fuel, into a pellet forming machine and extruding it at a temperature of 140-160°C and a pressure of 30-80 MPa to obtain biomass-derived pellet fuel.

[0031] In a more preferred embodiment, drying the composite material to a moisture content of 10%-15% includes: the drying is carried out at 80-120°C, the ventilation rate is 0.8-1.2 m / s, and the drying time is 20-30 minutes.

[0032] In a preferred embodiment, the density of the biomass-derived pellet fuel obtained is 1.1-1.35 g / cm³.

[0033] In a preferred embodiment, the biomass-derived pellet fuel obtained has a particle size of 6-10 mm and a length of 10-30 mm.

[0034] In a preferred embodiment, the method further includes: conducting quality inspection on the obtained biomass-derived pellet fuel and packaging qualified products.

[0035] In a preferred embodiment, the term "other waste" refers to the portion remaining after removing wet waste, hazardous waste, and recyclable waste in the household waste sorting process; or, the term "other waste" refers to waste collected from the "other waste" collection bin in the trash can, and / or "other waste" collected from the waste station.

[0036] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: This invention utilizes other waste after household waste sorting as raw materials, which are widely available and inexpensive. Through multi-stage sorting and crushing processes, it obtains base materials that meet the requirements for biomass-derived fuel preparation. By scientifically proportioning and adding auxiliary materials such as straw, waste wood chips, calcium hydroxide, calcium oxide, and sodium silicate, it significantly improves the fuel's calorific value, reduces ash content, and effectively inhibits the generation and emission of pollutants such as SO2, HCl, and dioxins. The equipment involved in the entire process is mature and easy to scale up for production, offering significant environmental and economic benefits, making it particularly suitable for promotion and application in areas without waste incineration facilities. Attached Figure Description

[0037] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0038] Figure 1 This is a flowchart illustrating the method described in this invention. Detailed Implementation

[0039] To make the above and other features and advantages of the present invention clearer, the invention will be further described below with reference to the accompanying drawings. It should be understood that the specific embodiments given herein are for the purpose of explanation to those skilled in the art and are exemplary only, not restrictive.

[0040] Example 1 like Figure 1 As shown, this embodiment provides a method for preparing biomass-derived fuel based on other waste, specifically including the following steps: Step S1: The sorted other waste is fed into a drum screen by a feeder for screening, separating materials with a particle size greater than 80mm and fine materials with a particle size less than 40mm, and collecting usable materials with a particle size between 40mm and 80mm.

[0041] Other waste (i.e., the portion remaining after removing wet waste, hazardous waste, and recyclable waste from the household waste sorting process) collected at various sorting stations in residential communities is transported by other waste collection trucks to a biomass-derived pellet fuel plant for designated storage. This other waste mainly includes combustible materials such as plastic film, textiles, paper, nut shells, small pieces of hard plastic, and small pieces of wood, as well as small amounts of impurities such as metal, glass, and ceramic jars.

[0042] Other waste is fed evenly and stably onto a rotary drum screen at a rate of 5-8 tons / hour using a plate feeder. Gradient screening technology is used for coarse separation of the waste. The rotary drum screen has an 80mm aperture. During screening, lightweight materials (>80mm, such as plastics and textiles) are separated from heavy materials (such as bones and shells) and fine materials (<40mm, such as mud, broken glass, and small stones). Special attention is paid to removing chlorinated plastics and glass / ceramic jars. After separation, usable material with a particle size between 40mm and 80mm is collected. This portion is the core raw material for subsequent processing, having already partially separated most of the large and fine impurities.

[0043] Step S2: The available material is sheared and crushed to obtain primary shredded material.

[0044] The usable material (40-80mm) collected in step S1 is fed into a low-speed, high-torque twin-shaft shear crusher. The main shaft speed is controlled at 30-50 rpm, the shearing force is 80-120 kN, and the blade gap is set to 18-22 mm. The material passes through the crushing chamber once, with a residence time of approximately 10-15 seconds. After crushing, the particle size of the material is mainly distributed in the range of 15-45 mm, with the proportion of particles with a diameter of 20-30 mm not less than 70%. This crushing effect fully dissociates flexible materials and shears rigid materials into blocks, significantly enhancing the separation efficiency of subsequent air classification and bouncing screening.

[0045] Step S3: The primary shredded material is subjected to magnetic separation to remove metal impurities, and then air separation and bouncing sieve to separate flexible and rigid materials.

[0046] First, the primary shredded material is passed through a magnetic separator to remove metal impurities, and the remaining material is the demetallized material.

[0047] The demetallized material is then fed into an air separator. The airflow speed and direction are controlled. The airflow speed is maintained between 7.5-14 m / s, and the airflow direction is at a 10°-20° angle to the horizontal plane. This allows lightweight, flexible materials (such as plastic film, fabric, and paper) to be blown away, achieving initial separation. Material not carried away by the air separator falls onto a bouncing screen.

[0048] The bouncing screen has an amplitude of 3-5mm, a frequency of 12-18Hz, and a screen plate inclination angle of 5°-15°. By vibrating and tilting the screen plate, it utilizes the difference in bouncing characteristics between rigid materials (such as nut shells, hard plastics, and small wooden blocks) and residual flexible materials to achieve further fine separation.

[0049] Flexible materials mainly refer to flammable materials that are easily carried away by airflow during the air separation process, and are soft, flexible, or easily torn, such as plastic film, fabric, and paper. Rigid materials mainly refer to flammable materials that are hard and not easily deformed and are separated during the bouncing screening process based on the difference in elasticity and rigidity, such as nut shells, small pieces of hard plastic, and small pieces of wood.

[0050] After air separation and bouncing screening, flexible materials (plastic film, fabric, paper, etc.) are effectively separated from rigid materials (nut shells, small pieces of hard plastic, small pieces of wood, etc.).

[0051] Step S4: The flexible material and the rigid material are finely crushed to obtain biomass substrate with a particle size of 3-5 mm.

[0052] For flexible materials, a high-speed rotor crusher is used. This equipment uses the impact and shearing forces generated by the high-speed rotor to crush the material to a preset fineness.

[0053] For rigid materials, a reversible high-speed hammer crusher is used. This equipment uses forward and reverse rotating hammers to strike the material in both directions, crushing it to the preset fineness to ensure consistency with the particle size of the crushed product for flexible materials.

[0054] In one embodiment, the specific operation is as follows: The flexible material is fed into the high-speed rotor crusher, the rotor speed is set to 1300 r / min, and the particle size of the crushed material is controlled at 3-5 mm.

[0055] Rigid objects are fed into a reversible high-speed hammer crusher, and the linear velocity of the hammer is set to 48 m / s. The particle size of the crushed material is also controlled at 3-5 mm.

[0056] Finally, the two crushed materials are mixed evenly to obtain the biomass substrate of the present invention.

[0057] Step S5: Mix the biomass base material with auxiliary materials, including straw, waste wood chips, calcium hydroxide, calcium oxide and sodium silicate, to form a composite material.

[0058] Mix the biomass base and auxiliary materials in the following weight ratios: Biomass substrate: 65-80 parts; Straw and waste wood chips: 15-30 parts; Calcium hydroxide: 1-3 parts; Calcium oxide: 1-3 parts; Sodium silicate: 0.5-2 parts.

[0059] In one specific embodiment, a twin-shaft mixer is used to perform the mixing operation according to the following parts by weight: Biomass substrate: 70 parts; Straw and waste wood chips: 25 portions; Calcium hydroxide: 2 parts; Calcium oxide: 2 parts; Sodium silicate: 1 part.

[0060] The mixing process parameters are set as follows: mixing time 7 minutes, mixer speed 25 rpm, to ensure that each component is evenly dispersed and forms a composite material with stable performance.

[0061] The synergistic effects of each component in this formulation are as follows: 70 parts of biomass substrate: As the main component, it provides the main fuel matrix and combustible material, ensuring the basic calorific value and combustion characteristics of the fuel.

[0062] 25 parts straw and waste wood chips: as a high-calorific-value supplementary material, significantly improve the calorific value of fuel, while improving pellet forming performance and enhancing pellet strength.

[0063] Two parts of calcium hydroxide: react with SO2 produced during combustion to form calcium sulfate, effectively reducing SO2 emissions.

[0064] Two parts of calcium oxide: react with HCl to form calcium chloride, effectively reducing HCl emissions.

[0065] One part sodium silicate: inhibits the formation of dioxins through catalysis.

[0066] The performance indicators of the biomass-derived fuel prepared in this embodiment are shown in Table 1. Thanks to the sulfur and chlorine fixation effects of calcium hydroxide and calcium oxide, and the inhibition of dioxin formation by sodium silicate, the fuel's pollutant emissions during combustion are significantly lower than those of the control group. The control group refers to the emission data from the direct incineration of other waste that has not undergone multi-stage sorting and sufficient pretreatment.

[0067] Table 1, Combustion performance of Example 1 and control project unit Example 1 control group Emission reduction rate <![CDATA[SO2 emissions]]> mg / m³ 110 450 75.5% HCl emissions mg / m³ 90 350 74.2% Dioxins ng TEQ / m³ 0.1 0.5 80% Step S6: Dry the composite material to a moisture content of 10%-15%.

[0068] The composite material is dried using specialized heating and ventilation equipment. The drying temperature is controlled at 80-120°C, the ventilation rate in the drying section is 0.8-1.2 m / s, and the drying time is 20-30 minutes, until the final moisture content stabilizes within the range of 10%-15%. In this embodiment, the drying temperature is controlled at 100°C, the ventilation rate is 1.0 m / s, and the drying time is 25 minutes.

[0069] The results of the verification of drying process parameters show that: The drying temperature is controlled at 80-120℃, which can effectively evaporate moisture without causing the decomposition of organic matter.

[0070] With a ventilation rate of 0.8-1.2 m / s, it can remove moisture without causing loss of fine materials.

[0071] The drying time is 20-30 minutes, which meets the requirements of continuous production.

[0072] The final moisture content is 10-15%, with an average of 12.5%, which ensures both moldability and increases calorific value.

[0073] Step S7: Place the dried composite material in a pellet forming machine and extrude it at a temperature of 150°C and a pressure of 30-80 MPa to obtain biomass-derived pellet fuel.

[0074] The dried composite material is placed in a pelletizing machine and extruded at 150°C and 30-80 MPa. The resulting biomass-derived pellet fuel has a diameter of 6-10 mm, a length of 10-30 mm, and a density of 1.1-1.3 g / cm³.

[0075] The results of the molding process parameter verification show that: A molding temperature of around 150°C can promote the softening of natural binders (lignin) in biomass and improve particle strength.

[0076] The extrusion pressure of 30-80MPa ensures both particle density and energy efficiency.

[0077] With a particle diameter of 6-10mm, it ensures both combustion efficiency and ease of transportation and storage.

[0078] Particle length should be 10-30mm to avoid feeding difficulties caused by excessive length.

[0079] Step S8: The biomass-derived pellet fuel is subjected to quality inspection, and qualified products are packaged.

[0080] The resulting biomass-derived pellet fuel undergoes quality inspection according to the technical specifications for solid biomass fuel briquettes. Inspection items include calorific value, ash content, moisture content, and pollutant emissions. Qualified products are packaged, typically in 25kg bags for easy manual handling, but 500kg bags are also available for large industrial users.

[0081] The biomass-derived pellet fuel prepared in this embodiment has the following performance indicators after testing: Calorific value: 16.8 MJ / kg; Ash content: 8.5%; Particle density: 1.2 g / cm³; SO2 emission concentration: 110 mg / m³; HCl emission concentration: 90 mg / m³; Dioxin emission concentration: 0.1 ng TEQ / m³.

[0082] Example 2 This embodiment is basically the same as Embodiment 1, except that: The range of composite material proportions used in this embodiment is as follows: Biomass substrate: 65 parts Straw and waste wood chips: 28 samples Calcium hydroxide: 2.5 parts Calcium oxide: 2.5 parts Sodium silicate: 2 parts.

[0083] Drying process parameters adjustment: Drying temperature: 120°C; Ventilation rate: 0.8m / s; Drying time: 30 minutes.

[0084] Molding process parameters adjustment: Molding temperature: 160°C; Extrusion pressure: 70MPa.

[0085] Technical effectiveness verification: The effects of the biomass-derived fuel technology prepared in this embodiment are as follows: SO2 emission concentration: 105 mg / m³, a 76.7% reduction compared to the untreated control group (450 mg / m³); HCl emission concentration: 85 mg / m³, a decrease of 75.7% compared to the control group (350 mg / m³); Dioxin emission concentration: 0.09 ng TEQ / m³, a decrease of 82.0% compared to the control group (0.5 ng TEQ / m³); Particle density: 1.32 g / cm³; Calorific value: 17.2 MJ / kg; Ash content on a dry basis: 8.2%.

[0086] Example 3 This embodiment is basically the same as Embodiment 1, except that: The range of composite material proportions used in this embodiment is as follows: Biomass substrate: 80 parts Straw and waste wood chips: 15 portions Calcium hydroxide: 2 parts Calcium oxide: 2 parts Sodium silicate: 1 part.

[0087] Drying process parameters adjustment: Drying temperature: 110°C; Ventilation rate: 0.9m / s; Drying time: 25 minutes.

[0088] Molding process parameters adjustment: Molding temperature: 155°C; Extrusion pressure: 60MPa.

[0089] Technical effectiveness verification: The effects of the biomass-derived fuel technology prepared in this embodiment are as follows: SO2 emission concentration: 135 mg / m³, a 70% reduction compared to the control group. HCl emission concentration: 105 mg / m³, a 70% reduction compared to the control group. Dioxin emission concentration: 0.12 ng TEQ / m³, a reduction of 76.0% compared to the control group; Particle density: 1.25 g / cm³; Calorific value: 16.2 MJ / kg; Ash content: 9.5%.

[0090] Comparative Example 1 Other waste from the same batch was directly fed into a single-stage crusher and crushed to 3-5mm without going through steps S1-S4 of Example 1. The same auxiliary material ratio as in Example 1 was added (70% biomass base, 25% straw and waste wood chips, 2% calcium hydroxide, 2% calcium oxide, and 1% sodium silicate). The mixture was dried to a moisture content of 12.5% ​​and then molded at 150°C and 50MPa.

[0091] This comparative example did not employ multi-stage sorting processes such as drum screening, magnetic separation, air separation, and bouncing screening, resulting in impurities (especially chlorinated plastics, metals, and glass) not being effectively removed.

[0092] Technical effectiveness verification: SO2 emission concentration: 280 mg / m³; HCl emission concentration: 220 mg / m³; Dioxin emission concentration: 0.32 ng TEQ / m³; Particle density: 1.09 g / cm³ (lower than 1.2 g / cm³ in Example 1); Calorific value: 15.1 MJ / kg (lower than 16.8 MJ / kg in Example 1); Ash content: 12.6% (higher than 8.5% in Example 1).

[0093] Results Analysis: Although the addition of auxiliary materials reduced pollutant emissions to some extent, the emission reduction effect was limited due to the failure to remove harmful components such as chlorinated plastics. Furthermore, the presence of impurities reduced particle density and calorific value, and increased ash content. This demonstrates that multi-stage sorting processes play a crucial role in improving fuel quality and reducing pollutant emissions.

[0094] Comparative Example 2 Following steps S1-S4 of Example 1, multi-stage sorting and crushing were performed to obtain biomass substrate. No auxiliary materials were added; only 100% biomass substrate was used. After drying to a moisture content of 12.5%, it was molded at 150°C and 50 MPa.

[0095] This comparative example lacks key excipients such as calcium hydroxide, calcium oxide, and sodium silicate, and therefore cannot effectively neutralize acidic gases and inhibit dioxin formation.

[0096] Technical effectiveness verification: SO2 emission concentration: 310 mg / m³; HCl emission concentration: 245 mg / m³; Dioxin emission concentration: 0.35 ng TEQ / m³; Particle density: 1.12 g / cm³; Calorific value: 18.5 MJ / kg; Ash content: 10.2%.

[0097] Results Analysis: Although the multi-stage sorting process removed some impurities, the pollutant reduction effect was still limited due to the lack of acid gas neutralizers and dioxin inhibitors. This demonstrates that the addition of auxiliary materials such as calcium hydroxide, calcium oxide, and sodium silicate plays a crucial role in achieving significant pollutant reduction.

[0098] Comparative Example 3 Following steps S1-S4 of Example 1, multi-stage sorting and crushing are performed to obtain biomass substrate. The following auxiliary materials are added in the specified proportions: Biomass substrate: 90 parts Straw and waste wood chips: 8 portions Calcium hydroxide: 0.5 parts Calcium oxide: 0.5 parts Sodium silicate: 1 part.

[0099] Afterwards, it is dried to a moisture content of 12.5% ​​and then molded at 150°C and 50MPa.

[0100] The proportion of base material in this comparative example is too high (90%), and the proportion of auxiliary materials is too low, especially the proportion of acid gas neutralizer is insufficient.

[0101] Technical effectiveness verification: SO2 emission concentration: 265 mg / m³; HCl emission concentration: 210 mg / m³; Dioxin emission concentration: 0.28 ng TEQ / m³; Particle density: 1.23 g / cm³; Calorific value: 16.0 MJ / kg; Ash content: 10.2%.

[0102] Results Analysis: Although the physical properties of the particles (density, calorific value) were acceptable, the pollutant reduction effect was far inferior to that of Example 1 due to the excessively high proportion of base material and insufficient proportion of key auxiliary materials. This proves that the 65-80% base material proportion and specific auxiliary material ratio range in this invention are crucial for achieving the best pollutant reduction effect.

[0103] Comparative Example 4 Following steps S1-S4 of Example 1, multi-stage sorting and crushing are performed to obtain biomass substrate. The following single auxiliary material is added in the following proportions: Biomass substrate: 70 parts; Straw and waste wood chips: 27 samples; Calcium hydroxide: 3 parts; Calcium oxide: 0 parts; Sodium silicate: 0 parts; Afterwards, it is dried to a moisture content of 12.5% ​​and then molded at 150°C and 50MPa.

[0104] This comparative example only adds calcium hydroxide, lacking calcium oxide and sodium silicate, and therefore cannot comprehensively inhibit various pollutants.

[0105] Technical effectiveness verification: SO2 emission concentration: 145 mg / m³; HCl emission concentration: 255 mg / m³; Dioxin emission concentration: 0.25 ng TEQ / m³; Particle density: 1.18 g / cm³; Calorific value: 16.5 MJ / kg; Ash content: 9.2%.

[0106] Results analysis: Adding calcium hydroxide alone can effectively reduce SO2 emissions, but its inhibitory effect on HCl and dioxins is limited. This demonstrates that the synergistic effect of the three auxiliary materials—calcium hydroxide, calcium oxide, and sodium silicate—is crucial for achieving comprehensive pollutant emission reduction.

[0107] Performance comparison summary: Table 2. Performance Comparison Table of Each Embodiment and Comparative Example index Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 National Standards Formula (base material / straw / wood chips / calcium hydroxide / calcium oxide / sodium silicate) 70 / 25 / 2 / 2 / 1 65 / 28 / 2.5 / 2.5 / 2 80 / 15 / 2 / 2 / 1 Unsorted / 25 / 2 / 2 / 1 100 / 0 / 0 / 0 / 0 90 / 8 / 0.5 / 0.5 / 1 70 / 27 / 3 / 0 / 0 — <![CDATA[SO2 emission concentration (mg / m³)]]> 110 105 135 280 310 265 145 ≤400 HCl emission concentration (mg / m³) 90 85 105 220 245 210 255 ≤60 (1-hour average) Dioxin emission concentration (ng TEQ / m³) 0.1 0.09 0.12 0.32 0.35 0.28 0.25 ≤0.5 Particle density (g / cm³) 1.20 1.32 1.25 1.09 1.12 1.23 1.18 ≥1.0 Calorific value (MJ / kg) 16.8 17.2 16.2 15.1 18.5 16.0 16.5 ≥14.5 Ash content (%) 8.5 8.2 9.5 12.6 10.2 10.2 9.2 ≤10 The performance comparison data of the above embodiments and comparative examples show that: 1. The fuels prepared in Examples 1-3 of this invention reduce SO2, HCl, and dioxin emissions by 70%-76.7%, 68.64%-70%, and 76.0%-82.0%, respectively, compared to the control group. This demonstrates that this invention, through the synergistic effect of multi-stage sorting process and specific auxiliary material ratios, can effectively control the generation and emission of harmful substances during combustion.

[0108] 2. Comparing Example 1 and Comparative Example 1, it can be seen that Comparative Example 1, which did not undergo multi-stage sorting, had SO2, HCl, and dioxin emissions that were 154.5%, 144.4%, and 220% higher than Example 1, respectively, with ash content 48.2% higher and calorific value 10.1% lower. This demonstrates the decisive role of multi-stage sorting process in removing harmful impurities such as chlorinated plastics and improving fuel quality.

[0109] 3. Comparing Example 1 with Comparative Examples 2-4, it can be seen that: The SO2, HCl and dioxin emissions of Comparative Example 2 (without additives) were 181.8%, 172.2% and 250% higher than those of Example 1, respectively, demonstrating that the addition of additives is crucial for pollutant emission reduction. The SO2, HCl and dioxin emissions of Comparative Example 3 (improper ratio) were 140.9%, 31.2% and 180% higher than those of Example 1, respectively, proving that the 65-80% base material ratio and specific range of excipients of this invention are indispensable for achieving the best results; The HCl and dioxin emissions of Comparative Example 4 (single excipient) were 183.3% and 150% higher than those of Example 1, respectively, demonstrating that the synergistic effect of the three excipients, calcium hydroxide, calcium oxide and sodium silicate, is crucial for the comprehensive suppression of various pollutants.

[0110] In summary, this invention effectively removes metallic minerals and chlorinated materials through multi-stage sorting, and by adding effective modification methods and combustion-aiding additives, it produces a novel biomass-derived fuel with high calorific value, low ash content, and compliance with harmful gas standards. This solves the technical problems of high pollutant emissions, low calorific value, and high ash content that exist in other waste resource utilization processes in existing technologies. It is particularly suitable for large-scale promotion and application in small cities without waste-to-energy incineration plants.

[0111] The specific embodiments of the present invention have been described in detail above, but they are merely examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications and substitutions to the present invention are also within the scope of the present invention. Therefore, all equivalent transformations and modifications made without departing from the spirit and scope of the present invention should be covered within the scope of the present invention.

Claims

1. A method for preparing biomass-derived fuel based on other waste, characterized in that, Includes the following steps: The collected waste is subjected to gradient screening to separate materials with a particle size larger than the first pore size and materials with a particle size smaller than the second pore size, and materials with a particle size between the first pore size and the second pore size are collected. The collected materials are sheared and crushed to obtain primary shredded material; The primary shredded material is subjected to magnetic separation to remove metal impurities, followed by air separation and bouncing sieve separation to separate flexible and rigid materials; The flexible and rigid materials are finely crushed to obtain biomass substrate with a particle size of 3-5 mm; The biomass base material is mixed with auxiliary materials to obtain biomass-derived fuel.

2. The method according to claim 1, characterized in that, The first aperture is 65-90mm, the second aperture is 25-50mm, and the difference between the first aperture and the second aperture is 30-50mm.

3. The method according to claim 1, characterized in that, The shearing and crushing process is carried out using a low-speed, high-torque shearing crusher.

4. The method according to claim 1, characterized in that, During the air separation process, the airflow velocity is 7.5-14 m / s, and the wind direction is at an angle of 10°-20° to the horizontal plane; The bouncing sieving is carried out through a bouncing screen, which has an amplitude of 3-5mm, a vibration frequency of 12-18Hz, and a screen plate inclination angle of 5°-15°.

5. The method according to claim 1, characterized in that, The flexible material and the rigid material are separately and independently finely crushed into materials with a particle size of 3-5 mm. The crushed flexible material and the crushed rigid material are then combined to obtain a biomass substrate with a particle size of 3-5 mm. Flexible materials are crushed using a rotor crusher; Rigid objects are crushed using a reversible hammer crusher.

6. The method according to claim 1, characterized in that, The auxiliary materials include biomass fuel, calcium hydroxide, calcium oxide, and silicates; wherein, The biomass fuel is one or more of the following: leaves, flowers, stems, roots, and fruit shells of plants; The silicate is one or more of sodium silicate, potassium silicate, calcium silicate, magnesium silicate, iron silicate, and aluminum silicate.

7. The method according to claim 6, characterized in that, The biomass-derived fuel comprises the following components in parts by weight: Biomass substrate: 60-85 parts Biomass fuel: 15-35 parts Calcium hydroxide: 1-4 parts Calcium oxide: 1-4 parts Silicate: 0.5-3 parts.

8. The method according to claim 1, characterized in that, The method further includes: drying the biomass-derived fuel to a moisture content of 10%-15%; The dried biomass-derived fuel is placed in a pellet forming machine and extruded into shape at a temperature of 140-160°C and a pressure of 30-80MPa to obtain biomass-derived pellet fuel. The process of drying the biomass-derived fuel to a moisture content of 10%-15% includes: the drying being carried out at 80-120°C, with a ventilation rate of 0.8-1.2 m / s, and a drying time of 20-30 minutes.

9. The method according to claim 8, characterized in that, The biomass-derived pellet fuel obtained has a density of 1.1-1.35 g / cm³, a particle size of 6-10 mm, and a length of 10-30 mm.

10. A biomass-derived fuel based on other waste, characterized in that, The biomass-derived fuel is prepared by the method described in any one of claims 1-9, and the biomass-derived fuel comprises: Biomass base and auxiliary materials, wherein the auxiliary materials include biomass fuel, calcium hydroxide, calcium oxide and silicates.

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