Method for synergistic resource utilization of organic waste

Abstract

The present application relates to the field of waste recycling, to solve the problem of poor process compatibility and product stability due to unstable raw material performance in the resource utilization of prior art, provide a kind of method for organic waste resource utilization, comprising the following steps: S100, set product parameters;Obtain raw material parameters;S200, according to product parameters and raw material parameters, obtain the dewatering target value of sludge and the mixing ratio of sludge and biomass material after dewatering;S300, with mixing ratio as standard, obtain the relationship curve between sludge powder particle size, biomass powder particle size and product physical properties;S400, according to the relationship curve, obtain the sludge powder particle size and biomass powder particle size when the product physical performance meets the set threshold value.The method provided by the present application can not only adapt to the characteristics of large difference of raw materials, but also realize the self-sustaining combustion of product, when used as fuel, with the advantages of stable calorific value, sufficient degree of combustion and the like.

Description

Technical Field

[0001] This invention relates to the field of waste recycling, and more specifically, to a method for the co-resource utilization of organic waste. Background Technology

[0002] Existing technologies for the resource-based treatment of sludge and agricultural and forestry waste have formed three main technical pathways:

[0003] 1. Sludge treatment technologies: Primarily co-processing in cement kilns, supplemented by landfill, composting, incineration, and anaerobic digestion. Cement kiln co-processing, as the mainstream technology, involves mixing dewatered sludge with cement raw materials and feeding it into a kiln (temperature ≥1450℃). High temperatures are used to render the sludge harmless (killing pathogens and decomposing organic matter), while simultaneously replacing some fuels (such as coal). Furthermore, heavy metals in the sludge can be solidified in the cement clinker. Landfilling is widely used due to its low cost, but it occupies land and poses a risk of leachate pollution; current policies discourage its use. Sludge can be disposed of by landfill; composting requires controlling the sludge moisture content (usually ≤60%) and heavy metal content, and is suitable for agricultural reuse, but the treatment cycle is long (15-30 days); incineration can reduce sludge volume (reduction rate of over 90%), but requires auxiliary fuels (such as coal and natural gas) to maintain the combustion temperature (≥850℃), resulting in high carbon emissions and high flue gas treatment costs; anaerobic digestion produces biogas through microbial degradation, but requires high organic matter content in the sludge (≥25%), and the gas production efficiency is significantly affected by seasonal temperature.

[0004] 2. Agricultural and forestry waste utilization technologies: These mainly include direct incineration for heating, solidified fuel, and gasification power generation. Direct incineration (such as open burning of straw) causes serious pollution and has been banned in many places. Solidified fuel requires the moisture content of the raw materials to be controlled at 10%-15%, which requires additional drying energy consumption. Gasification power generation has high requirements for the uniformity of raw material particle size (usually ≤5cm) and the cost of gas purification is high, making it uneconomical for small and medium-sized projects.

[0005] 3. Preliminary attempts at co-processing: Some technologies simply mix sludge with agricultural and forestry waste and then incinerate or produce fuel. For example, dewatered sludge (moisture content 75%-80%) is mixed with straw in a 1:3 ratio and then directly fed into a boiler for incineration to reduce sludge treatment costs; or the sludge is crushed, mixed and then pressed into fuel. However, because the pretreatment process is not optimized for the characteristics of the materials, problems such as uneven mixing, low strength of the fuel, and coking during combustion (ash melting point ≤1000℃) often occur.

[0006] Existing technologies for the co-treatment of sludge and agricultural and forestry waste have the following drawbacks:

[0007] 1. Poor material compatibility and immature pretreatment technology.

[0008] The physical properties of sludge (high moisture content, high viscosity) and agricultural and forestry waste (mainly wood fiber, with large fluctuations in moisture content) are significantly different. Existing technologies lack targeted synergistic pretreatment solutions: simple mixing can easily lead to material stratification, affecting subsequent combustion or molding stability.

[0009] Sludge incineration alone requires 20%-30% of auxiliary fuel to compensate for its low calorific value (approximately 600-800 kcal / kg), while the incineration of agricultural and forestry waste alone is prone to problems such as "flame detachment" and "flameout". Existing co-processing technologies have not optimized fuel ratios and combustion parameters, resulting in low boiler thermal efficiency and unstable steam output, making it difficult to meet industrial steam demand.

[0010] 3. Low system integration and limited adaptability.

[0011] Existing technologies are mostly simple combinations of "processing units + energy units", failing to form an integrated system from raw material collection, pretreatment, fuel preparation to steam supply; and they do not take into account regional differences in raw material characteristics (such as the abundance of bamboo resources in Yibin). The generalized design results in poor adaptability to raw materials, making it difficult to achieve large-scale application in specific regions.

[0012] There is an urgent need for a method to co-treat sludge and agricultural and forestry waste, which can accommodate the high degree of differentiation of raw materials as much as possible, while meeting the requirements of high calorific value, calorific value stability and structural stability when the product is used as fuel. Summary of the Invention

[0013] The purpose of this invention is to provide a method for the co-resource utilization of organic waste, which solves the problem that the unstable performance of raw materials leads to poor process compatibility and product stability in the resource utilization of existing technologies. It also realizes the self-sustaining combustion of the product, and when used as fuel, it has the advantages of stable calorific value and high combustion completeness.

[0014] The embodiments of the present invention are achieved through the following technical solutions:

[0015] A method for the co-resource utilization of organic waste includes the following steps:

[0016] S100. Set product parameters, including: maximum moisture content and minimum calorific value;

[0017] Obtain raw material parameters, including: initial moisture content of sludge, lower heating value of sludge on a dry basis, moisture content of biomass material, and calorific value of biomass material;

[0018] S200. Based on the product parameters and raw material parameters, obtain the target value for sludge dewatering and the mixing ratio of dewatered sludge to biomass materials.

[0019] Using the mixing ratio in S200 as the standard, obtain the relationship curves between the particle size of sludge powder, the particle size of biomass powder and the physical properties of the product;

[0020] S400. Based on the relationship curve, obtain the particle size of sludge powder and biomass powder when the physical properties of the product meet the set threshold.

[0021] Preferably, the method further includes: a product manufacturing process; the manufacturing process includes:

[0022] A100: After the raw sludge is treated to the dewatering target value through the dewatering process, it is then crushed to the sludge powder particle size in S400 through the crushing process to obtain sludge powder.

[0023] Biomass materials are pulverized to the biomass powder particle size in S400 through a pulverizing process to obtain biomass powder.

[0024] A200, sludge powder, and biomass powder are processed into fuel products through a molding process.

[0025] Preferably, the dewatering process includes: after removing solid impurities from the raw sludge, it is first subjected to cell wall breaking treatment, and then subjected to pressure filtration treatment; the dewatering target value is that the moisture content of the sludge is 45%-55%.

[0026] Since this invention requires reducing the moisture content of sludge to 50% ± 5%, while the moisture content of raw sludge is around 80%, directly achieving this through filter press would significantly increase the operating cost of the filter press. Therefore, this invention first uses an ultra-high pressure pulse puncture cell disruptor to break down the sludge cells, and then uses a fully automatic ultra-high pressure diaphragm filter press to remove free water and some interstitial water from the sludge through mechanical pressing, achieving deep dewatering with higher efficiency. The removal of solid impurities, especially sharp metal impurities, prevents damage to the filter cloth in subsequent processes. Solid impurities can be removed using filter screens and iron removers.

[0027] Preferably, when the sludge has a moisture content of 50%, its calorific value is 500-800 kcal / kg, and when the biomass material has a moisture content of ≤20%, its calorific value is ≥3500 kcal / kg.

[0028] The applicant discovered through experiments that only when the moisture content and calorific value of the sludge and biomass materials meet the values ​​set in this case can the mixing ratio achieve better product physical properties.

[0029] Preferably, when blending, biomass materials account for 50%-70% by weight.

[0030] Preferably, the biomass material includes wood or bamboo.

[0031] Compared to herbaceous biomass, such as straw, wood or bamboo are more likely to meet the physical performance requirements of products.

[0032] Preferably, the A100 includes:

[0033] Raw sludge is crushed to obtain sludge particles;

[0034] Biomass materials are crushed to obtain biomass pellets;

[0035] The sludge particles and biomass particles are mixed according to the mixing ratio in S200, and then crushed to obtain mixed powder.

[0036] After dewatering, the sludge and biomass materials are crushed separately and then mixed together before entering the pulverizing process. Because they share the same pulverizer, the particle size uniformity of the output materials is higher. When obtaining the particle size of both materials through S300 and S400, the process is simplified due to the consistent particle size. Furthermore, maintaining consistent particle size further simplifies the process.

[0037] Preferably, the discharge particle size of the crushing process is ≤5cm, the discharge particle size of the pulverizing process is ≤1mm, and the rotation speed of the mixing process is 30-50r / min.

[0038] The rotation speed during the mixing process affects the mixing uniformity and the deviation in product calorific value.

[0039] When the rotation speed is below 30 r / min: the twin-shaft paddles cannot fully agitate the high-viscosity sludge powder and the light biomass powder, and the material shows obvious stratification (such as sludge accumulation at the bottom and biomass floating at the top). The coefficient of variation of the mixing uniformity is >10%, which directly leads to local moisture content exceeding the standard (deviation >5%) in the subsequent granulation process. The final product calorific value fluctuates by more than ±5%, which does not meet the core requirement of "calorific value ≥2500kcal / kg and deviation ≤2%".

[0040] When the rotation speed is higher than 50 r / min: the shear force generated by the excessively high rotation speed will destroy the structure of biomass fiber, and the material pulverization rate will rise sharply from 1.5% to 3.2%. On the one hand, this leads to powder waste (loss rate increases by 1.7%), and on the other hand, fine powder is prone to forming "hollow particles" during granulation, and the granulation rate drops from 95% to 88%. Furthermore, fine powder will cause dust pollution in the workshop when it is dispersed by airflow, which will bring safety hazards.

[0041] When the rotation speed is between 30-50 r / min: the coefficient of variation of mixing uniformity is ≤3.3%, the material pulverization rate is controlled at 1.5%-1.7%, and the final product calorific value deviation is stable within ±2%. It also takes into account mixing efficiency (completing single batch mixing in 15 minutes) and material integrity. It is the only optimal rotation speed range that can balance "uniformity-pulverization rate-calorific value stability".

[0042] Uniform mixing is a prerequisite for stable calorific value: The core contradiction in the co-resource utilization of organic waste is the matching of "high moisture content of sludge (45%-55%) and high calorific value of biomass (above 3500kcal / kg)". If the mixing is uneven, the calorific value will drop sharply in some areas where sludge is concentrated due to excessive moisture content (e.g., local calorific value <2000kcal / kg), while in some areas where biomass is concentrated, overheating and carbonization will occur during granulation due to excessively low moisture content (particle temperature > ambient temperature +8℃). A rotation speed of 30-50r / min can ensure that the two materials are fully intertwined at the microscopic level, with the deviation of the proportion of sludge and biomass in each gram of mixed material being ≤3%.

[0043] 2. Quantitative binding of rotation speed parameters and calorific value deviation: As shown in the previous experiment, when the rotation speed is in the range of 30-50 r / min, the calorific value deviation is strictly controlled within ±2%. However, once it exceeds this range, the calorific value deviation will "non-linearly expand" - for every 10 r / min decrease in rotation speed, the calorific value deviation expands by ±2%; for every 10 r / min increase, the calorific value deviation expands by ±1.5%, and it cannot be corrected by subsequent processes (such as adjusting the granulation temperature can only improve the granulation rate, but cannot make up for the calorific value stratification problem).

[0044] Preferably, the rotation speed of the pulverizing process is 1200-1500 r / min.

[0045] Preferably, the temperature of the molding process is 70-90℃ and the extrusion pressure is 8-12MPa.

[0046] Too low a temperature can lead to loose and easily broken pellets, while too high a temperature can cause the material to stick to the die ring, affecting pelleting efficiency. Limiting the extrusion pressure ensures that the pellet density reaches 1.1-1.3 g / cm³, meeting the requirements for subsequent combustion and storage strength.

[0047] The present invention has at least the following beneficial effects:

[0048] The method for co-utilizing organic waste provided by this invention not only adapts to the characteristics of large differences in raw materials, but also achieves self-sustaining combustion of the product. When used as fuel, it has the advantages of stable calorific value and high combustion completeness. After crushing the sludge and biomass materials, they are jointly transported to the crushing process, which simplifies the production process. At the same time, the uniformity of the mixture and the stability of the product's calorific value are ensured by controlling the mixing process. The sludge is first dewatered, which not only reduces the amount of leachate generated in subsequent treatment, but also reduces the amount of biomass materials used when the product reaches the product parameters, thereby increasing the resource utilization of sludge and improving the physical properties of the product. Detailed Implementation

[0049] To make the objectives, methods, and advantages of the embodiments of the present invention clearer, the methods in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0050] Example 1: A method for the co-utilization of organic waste, comprising the following steps:

[0051] S100. Set product parameters, including: maximum moisture content and minimum calorific value;

[0052] Obtain raw material parameters, including: initial moisture content of sludge, lower heating value of sludge on a dry basis, moisture content of biomass material, and calorific value of biomass material;

[0053] S200. Based on the product parameters and raw material parameters, obtain the target value for sludge dewatering and the mixing ratio of dewatered sludge to biomass materials.

[0054] Using the mixing ratio in S200 as the standard, obtain the relationship curves between the particle size of sludge powder, the particle size of biomass powder and the physical properties of the product;

[0055] S400. Based on the relationship curve, obtain the particle size of sludge powder and biomass powder when the physical properties of the product meet the set threshold.

[0056] In practice, existing technologies often encounter problems such as uneven mixing, low fuel strength, and coking (ash melting point ≤1000℃) when simply mixing sludge with agricultural and forestry waste for incineration or fuel production. For example, there are significant differences between the high moisture content and high viscosity of sludge and the physical characteristics of agricultural and forestry waste, which is mainly composed of wood fiber and has large fluctuations in moisture content. Existing technologies lack targeted synergistic pretreatment solutions: simple mixing easily leads to material stratification, affecting subsequent combustion or fuel production stability.

[0057] Sludge incineration alone typically requires 20%-30% auxiliary fuel to compensate for its low calorific value, while the incineration of agricultural and forestry waste alone is prone to problems such as "flame detachment" and "flameout". Existing co-processing technologies have not optimized fuel ratios and combustion parameters, resulting in low boiler thermal efficiency and unstable steam output, making it difficult to meet industrial steam demand.

[0058] This embodiment allows setting product parameters based on the design specifications of a biomass steam boiler. For example, the maximum moisture content is 30%, and the minimum calorific value is 2500 kcal / kg.

[0059] As an example, the biomass material has a moisture content lower than the maximum moisture content and a calorific value higher than the minimum calorific value.

[0060] While mixing biomass materials with sludge can ensure that the moisture content and calorific value of the mixture meet product parameters, the strength of the final product is also related to the mixing ratio. Since the calorific value of virgin sludge typically does not exceed 800 kcal / kg, while the target calorific value of the product is much higher, the proportion of biomass materials needs to be significantly higher than that of sludge to meet the product parameter requirements. At low dosages, biomass materials can act as a structural framework to improve product strength. However, in this embodiment, with high dosages, increasing the proportion of biomass materials can actually damage the internal structure of the product particles, leading to a significant decrease in strength. The applicant hypothesizes that the reason is at least that sludge has limited binding capacity; when the biomass proportion is too high, it cannot be fully encapsulated, resulting in loose areas within the particles that are prone to breakage under stress. Therefore, this embodiment additionally considers the physical properties of the product and selects the particle sizes of both the sludge powder and the biomass powder accordingly.

[0061] If the physical properties of a product, such as compressive strength, are to be ensured by changing the blending ratio, it is usually necessary to reduce the amount of biomass material used to a certain extent. However, to achieve a set minimum calorific value, the calorific value of the biomass material needs to be sufficiently high, thus limiting the scope of its application. In this embodiment, to improve the versatility of the production process, the physical properties of the product are improved simply by adjusting the particle size of the powder.

[0062] Because the high moisture content of raw sludge reduces its effectiveness in binding biomass materials and increases the difficulty of reducing the moisture content of the blended material to below its maximum moisture content, sludge usually needs to undergo dewatering treatment first. The calorific value of the dewatered sludge can be calculated based on the lower heating value of the sludge on a dry basis, as follows:

[0063] , of which M ar For the target moisture content, M ad Q represents the initial moisture content. ad,net Q is the lower heating value on a dry basis. ar,net It is the lower heating value on a wet basis.

[0064] The lower heating value on a dry basis refers to the calorific value per unit of dry solids after deducting the latent heat of vaporization of moisture.

[0065] The lower heating value on a wet basis refers to the calorific value per unit of wet sludge, which increases as the moisture content decreases.

[0066] In addition, sludge is easier to mix evenly with biomass materials after it has been dewatered.

[0067] When determining the blending ratio, there may be multiple blending ratios that meet the product parameter requirements. In such cases, the appropriate ratio can be selected based on actual needs. For example, if the goal is to increase the proportion of sludge resource utilization, a blending ratio with a higher sludge content can be prioritized. Conversely, processes such as sludge dewatering and transportation can significantly increase production costs; to reduce these costs, a blending ratio with a lower sludge content can be prioritized.

[0068] When determining the particle size of sludge powder and biomass powder, there may be multiple options. In this case, it is preferable to choose a larger particle size parameter to reduce the pulverization requirements and improve pulverization efficiency.

[0069] Example 2: The product manufacturing process includes:

[0070] A100: After the raw sludge passes through a filter screen and iron remover to remove solid impurities, it is first subjected to ultra-high pressure pulse piercing cell wall breaking treatment, and then to fully automatic ultra-high pressure diaphragm filter press for filtration until the target dewatering value is reached. Following this, a crushing process is performed to obtain sludge particles. The target dewatering value is a sludge moisture content of 45%-55%. The filtration pressure is 0.7 MPa, the single filtration cycle is 40-60 minutes, and the sludge feed rate is 15-20 m / s². 3 / h.

[0071] Biomass materials are crushed to obtain biomass pellets;

[0072] The sludge particles and biomass particles are mixed in a twin-shaft paddle mixer according to the mixing ratio in S200, and then crushed to the particle size in S400 to obtain mixed powder; by weight, biomass material accounts for 50%-70% during mixing;

[0073] The output particle size of the crushing process is ≤5cm, the output particle size of the pulverizing process is ≤1mm, the rotation speed of the mixing process is 30-50r / min, and the mixing time is 15-20min; the rotation speed of the pulverizing process is 1200-1500r / min.

[0074] A200: The mixed powder is formed by a ring die pellet mill. Through the extrusion action of the ring die and the pressure roller, the mixed powder is extruded into regular granular fuel products. After being cooled by a cooling conveyor belt, the products are transported to the finished product warehouse for storage. The particle diameter of the fuel products is 8-10mm, and the length is 1.5-2.0 times the diameter.

[0075] The temperature of the molding process is 70-90℃, and the extrusion pressure is 8-12MPa; the temperature of the granules outlet needs to be reduced to ±5℃ of the ambient temperature (cooling time is about 5-8 minutes) to prevent the accumulation of high-temperature granules from causing mold.

[0076] The proportion of qualified particles (without obvious cracks and a breakage rate of ≤3%) in the finished product must be ≥95%. Unqualified fragments are removed by a screening device (the fragments can be returned to the crusher for reprocessing).

[0077] When the sludge has a moisture content of 50%, its calorific value is 500-800 kcal / kg; when the biomass material has a moisture content of ≤20%, its calorific value is ≥3500 kcal / kg.

[0078] Application example: See Table 1 for the selection and proportioning of blended raw materials.

[0079] Table 1

[0080] name Calorific value Moisture content / % Compatibility ratio Weighted heat value Weighted moisture content sludge 500 50 40% 200 20 Furniture waste 5500 16 40% 2200 6.4 fir wood 3600 15 20% 720 3 total 3120 29.4

[0081] Case 1: The production process includes:

[0082] A100: After the raw sludge passes through a filter screen and iron remover to remove solid impurities, it is first subjected to ultra-high pressure pulse piercing and cell wall breaking treatment, and then to fully automatic ultra-high pressure diaphragm filter press for filtration until the target dewatering value is reached. Following this, a crushing process is performed to obtain sludge particles; the target dewatering value is a sludge moisture content of 50%. The filtration pressure is 0.7 MPa, the single filtration cycle is 400 min, and the sludge feed rate is 15 m / s². 3 / h.

[0083] Biomass materials are crushed to obtain biomass pellets;

[0084] The sludge particles and biomass particles are mixed in accordance with the mixing ratio in Table 1 by a twin-shaft paddle mixer, and then crushed to 0.8mm by a crushing process to obtain mixed powder.

[0085] The output particle size of the crushing process is 4 cm, the rotation speed of the mixing process is 30 r / min, and the mixing time is 15 min; the rotation speed of the pulverizing process is 1200 r / min.

[0086] A200: The mixed powder is formed by a ring die pellet mill. Through the extrusion action of the ring die and the pressure roller, the mixed powder is extruded into regular granular fuel products. After being cooled by a cooling conveyor belt, the products are transported to the finished product warehouse for storage. The fuel product has a particle diameter of 8mm and a length that is 1.5 times the diameter.

[0087] The temperature of the molding process is 70℃ and the extrusion pressure is 8MPa; the particle outlet temperature needs to be reduced to ambient temperature ±5℃ and the cooling time is 6min to prevent high-temperature particles from accumulating and causing mold.

[0088] Unqualified fragments are removed by a screening device and returned to the crusher for reprocessing.

[0089] Case 2: The production process includes:

[0090] A100: After the raw sludge passes through a filter screen and iron remover to remove solid impurities, it is first subjected to ultra-high pressure pulse piercing and cell wall breaking treatment, and then to fully automatic ultra-high pressure diaphragm filter press for filtration until the target dewatering value is reached. Following this, a crushing process is performed to obtain sludge particles; the target dewatering value is a sludge moisture content of 50%. The filtration pressure is 0.7 MPa, the single filtration cycle is 400 min, and the sludge feed rate is 15 m / s². 3 / h.

[0091] Biomass materials are crushed to obtain biomass pellets;

[0092] The sludge particles and biomass particles are mixed in accordance with the mixing ratio in Table 1 by a twin-shaft paddle mixer, and then crushed to 0.8mm by a crushing process to obtain mixed powder.

[0093] The output particle size of the crushing process is 4 cm, the rotation speed of the mixing process is 50 r / min, and the mixing time is 15 min; the rotation speed of the pulverizing process is 1500 r / min.

[0094] A200: The mixed powder is formed by a ring die pellet mill. Through the extrusion action of the ring die and the pressure roller, the mixed powder is extruded into regular granular fuel products. After being cooled by a cooling conveyor belt, the products are transported to the finished product warehouse for storage. The fuel product has a particle diameter of 8mm and a length that is 1.5 times the diameter.

[0095] The temperature of the molding process is 90℃ and the extrusion pressure is 8MPa; the particle outlet temperature needs to be reduced to ambient temperature ±5℃ and the cooling time is 6min to prevent high-temperature particles from accumulating and causing mold.

[0096] Unqualified fragments are removed by a screening device and returned to the crusher for reprocessing.

[0097] Case 3: The production process includes:

[0098] A100: After the raw sludge passes through a filter screen and iron remover to remove solid impurities, it is first subjected to ultra-high pressure pulse piercing and cell wall breaking treatment, and then to fully automatic ultra-high pressure diaphragm filter press for filtration until the target dewatering value is reached. Following this, a crushing process is performed to obtain sludge particles; the target dewatering value is a sludge moisture content of 50%. The filtration pressure is 0.7 MPa, the single filtration cycle is 400 min, and the sludge feed rate is 15 m / s². 3 / h.

[0099] Biomass materials are crushed to obtain biomass pellets;

[0100] The sludge particles and biomass particles are mixed in accordance with the mixing ratio in Table 1 by a twin-shaft paddle mixer, and then crushed to 0.8mm to obtain mixed powder.

[0101] The output particle size of the crushing process is 4 cm, the rotation speed of the mixing process is 40 r / min, and the mixing time is 15 min; the rotation speed of the pulverizing process is 1300 r / min.

[0102] A200: The mixed powder is formed by a ring die pellet mill. Through the extrusion action of the ring die and the pressure roller, the mixed powder is extruded into regular granular fuel products. After being cooled by a cooling conveyor belt, the products are transported to the finished product warehouse for storage. The fuel product has a particle diameter of 8mm and a length that is 1.5 times the diameter.

[0103] The temperature of the molding process is 80℃ and the extrusion pressure is 8MPa; the particle outlet temperature needs to be reduced to ambient temperature ±5℃ and the cooling time is 6min to prevent high-temperature particles from accumulating and causing mold.

[0104] Unqualified fragments are removed by a screening device and returned to the crusher for reprocessing.

[0105] Comparative Example 1: The difference from Case 3 is that the rotation speed of the mixing process is 20 r / min.

[0106] Comparative Example 2: The difference from Case 3 is that the rotation speed of the mixing process is 60 r / min.

[0107] Comparative Example 3: The difference from Case 3 is that the amount of fir wood used is increased by 50%.

[0108] Comparative Example 4: The difference from Case 3 is that the fir wood was replaced with straw, which has a calorific value of 4050 kcal / kg and a moisture content of 15%.

[0109] Comparative Example 5: The difference from Case 3 is that the particle size of the mixed powder is 1.2 mm.

[0110] Tests: Fuel products prepared according to the methods provided in Cases 1-3 and Comparative Examples 1-5 were subjected to tests on calorific value (kcal / kg), calorific value deviation (%), combustion completeness (%), and compressive strength (N). The test results are shown in Table 2. Calorific value deviation represents the performance stability of the same batch of products produced using the same production process. Calorific value deviation = 100% * (maximum calorific value - minimum calorific value) / maximum calorific value.

[0111] Table 2

[0112] Case 1 Case 2 Case 3 Comparative Example 1 Calorific value 2989 3047 3095 2356 Calorific value deviation 1.6 1.8 1.5 5.8 Complete combustion 93 97 95 87 compressive strength 796 812 830 473 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Calorific value 2836 3160 3074 3050 Calorific value deviation 3.8 4.2 1.7 1.8 Complete combustion 96 97 97 95 compressive strength 655 743 629 584

[0113] As can be seen from the test results of Cases 1-3, the fuel products prepared according to the method provided by the present invention not only meet the design specifications of conventional biomass steam boilers in terms of calorific value, but also have good calorific value stability, combustion completeness and compressive strength.

[0114] A comparison of Comparative Examples 1-2 and Case 3 reveals that the rotational speed during the mixing process significantly impacts the calorific value deviation of the product, meaning that the stability of product performance is compromised. The applicant hypothesizes that the rotational speed affects the uniformity and pulverization rate of the mixed materials. Too low a speed results in poor mixing uniformity, while too high a speed increases the proportion of excessively fine powder, which easily forms void particles during granulation. Furthermore, due to impaired uniformity, the compressive strength of some products also decreases to some extent.

[0115] In biomass or industrial solid waste granulation, such as biomass densification granulation or solid waste recycling pellet preparation, hollow pellets refer to substandard finished pellets with obvious pores, cavities, or loose holes inside. Visually, they may be accompanied by surface depressions or cracks, or, upon dissection, reveal a loose, porous internal structure. The core characteristics and causes of these pellets can be divided into the following two points:

[0116] 1. Structural characteristics: The interior contains pores and cavities of varying sizes, with a porosity much higher than that of qualified dense particles. Some cavities may form through channels. Externally, it may appear as a rough surface with pits or even cracks, exhibiting poor mechanical strength and being easily broken.

[0117] 2. Core causes: The raw material's moisture content is too high or too low; rapid evaporation during granulation creates vapor bubbles trapped inside the granules. Uneven particle size distribution prevents fine powder from tightly packing coarse material, leading to gaps. Process parameters: Inappropriate ring die compression ratio in the granulator results in insufficient compression force, preventing adequate compaction of the raw material. Excessively high granulation temperature causes volatile components in the raw material to escape rapidly, forming voids before the granules cool. Excessively fast feeding speed results in a short residence time of the material within the die orifice, failing to complete the densification process.

[0118] Equipment factors: Severe wear on the inner wall of the ring die, blockage or deformation of the die holes, resulting in uneven force on the material during extrusion and a loose internal structure.

[0119] Hollow particles directly reduce the bulk density, mechanical strength, and combustion efficiency of products. They are also prone to breakage and dust generation during storage and transportation, affecting the subsequent resource utilization effect, such as incomplete combustion when used as fuel and poor molding stability when used as raw materials.

[0120] In addition, the calorific value of the product in Comparative Example 1 dropped sharply. The applicant speculated that the reason might be that due to uneven mixing of the system, under the same molding process conditions, some raw materials were difficult to mold, while the amount of sludge in the successfully molded products increased.

[0121] A comparison of Comparative Examples 3-4 and Case 3 shows that increasing the amount of cedar wood or replacing it with an equal amount of straw significantly reduced the compressive strength of the product. Increasing the amount of cedar wood also led to an increase in the deviation in calorific value; the applicant hypothesizes that this is because the increased amount of cedar wood impaired the uniformity of the mixture.

[0122] As can be seen from the comparison between Comparative Example 5 and Case 3, excessively large particle size of the mixed powder can also significantly affect the compressive strength of the product.

[0123] Furthermore, the deviations between the calorific values ​​and theoretical calorific values ​​of the products in Comparative Examples 3 and 4 are greater than those in Case 3. The applicant hypothesizes that the increased presence of wood affected by ash or sulfur and nitrogen in the sludge leads to the ash's inhibitory effect on combustion temperature and the endothermic reaction of sulfur / nitrogen oxidation, offsetting more of the heat released from carbon combustion. Straw, on the other hand, may be more susceptible to the aforementioned effects or, under pressure, its lower porosity limits the release of volatiles during the rapid combustion stage, resulting in decreased combustion efficiency and ultimately a lower effective calorific value.

[0124] In summary, the present invention has at least the following advantages:

[0125] 1. The efficiency of sludge treatment and the rate of resource utilization have been significantly improved, solving the core pain point of "low calorific value and inability to sustain combustion".

[0126] Existing technologies for raw sludge (with a moisture content of around 80%) often employ simple dewatering (e.g., reducing it to only 60%-70%) or single blending, resulting in the sludge still requiring significant external energy purchases for combustion and low resource utilization rates. This invention utilizes a stepped process of "deep dewatering (80%→50%) + precise crushing and pulverization (≤1mm) + proportional blending (moisture content ≤30%, calorific value ≥2500kcal / kg)" to ensure the mixed materials achieve a stable calorific value reaching the self-sustaining combustion threshold, eliminating the need for external combustion energy. Furthermore, granulation (granulation rate ≥95%) standardizes and stores sludge-derived fuel, further expanding its application scenarios.

[0127] 2. Overall processing costs are reduced, resulting in a significant cost-performance advantage.

[0128] Cost optimization is achieved by addressing both equipment energy consumption and material consumption.

[0129] Energy consumption cost: The deep dewatering stage adopts medium-pressure pressing of 0.7MPa, and the filtration time is shortened to 40-60 minutes, reducing the energy consumption of dewatering per ton of sludge by 15%-20%; the granulation stage uses precise temperature control of 70-90℃ ring die to avoid energy waste caused by high-temperature heating, and the energy consumption of producing per ton of granules is reduced by 10% compared with existing technologies.

[0130] Material cost: The blending ratio of high-calorific-value biomass materials is controlled at 50%-70% (most existing technologies are above 75%). At the same time, unqualified pelleted material (≤3%) is returned to the crushing process for recycling, reducing the material loss rate to below 5%. The biomass raw material cost per ton of finished fuel is reduced by 8%-12%, and the overall cost-effectiveness is improved by more than 20%.

[0131] 3. It has strong process compatibility, is easy to operate, and has high stability.

[0132] Existing technologies often experience process interruptions due to fluctuations in sludge moisture content (above ±5%). This invention achieves high stability through precise control of multiple parameters:

[0133] Pretreatment stage: The crushing and pulverizing process controls the moisture content of sludge particles (45%-55%) and biomass particles (≤20%) to prevent material adhesion and blockage; the blending stage uses bi-shaft paddle mixing (30-50r / min) and timed mixing for 15-20 minutes to ensure that the moisture content deviation at different points is ≤5%, solving the problem of uneven mixing in existing technologies.

[0134] Equipment compatibility: Mature equipment such as plate and frame filter press (high dewatering efficiency) and ring die pellet mill (420mm diameter, suitable for biomass) are selected. The parameters of each process (such as feed rate 15-20m³ / h, extrusion pressure 8-12MPa) can be flexibly adjusted according to the sludge type (municipal / winery) without the need to replace the core equipment. Compared with the existing "single sludge-specific equipment", it has stronger compatibility, reduced operation difficulty, and reduced the training cost of operation and maintenance personnel by 30%.

[0135] 4. Upgraded clean and environmentally friendly performance, meeting "dual carbon" requirements.

[0136] Compared to existing technologies with high pollution and high carbon emissions, this invention reduces pollutant generation and carbon emissions at the source:

[0137] Pollution control: Deep dewatering removes more than 60% of the free water in the sludge, reducing the amount of leachate generated during subsequent treatment (the amount of leachate per ton of sludge is reduced to less than 0.3 tons, while existing technologies require ≥0.5 tons); after granulation, there is no significant dust generation during combustion (particle size 8-10mm), and due to the stable calorific value, the combustion efficiency is improved, reducing the particulate matter emission concentration in the exhaust gas to less than 30mg / Nm³.

[0138] Carbon emissions: Since there is no need to purchase external coal / natural gas for combustion, carbon emissions per ton of sludge treatment are reduced by 0.8-1.2 tons of CO2 (compared to about 1.5-2.0 tons of CO2 with existing technology). At the same time, it realizes the resource utilization of agricultural and forestry waste (waste bamboo chips, camphor leaves, etc.) to replace fossil energy, which can reduce CO2 emissions by more than 15,000 tons per year, which is in full compliance with the national "dual carbon" policy and environmental protection requirements.

[0139] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. 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.

Claims

1. A method for the co-utilization of organic waste, characterized in that, Includes the following steps: S100. Set product parameters, including: maximum moisture content and minimum calorific value; Obtain raw material parameters, including: initial moisture content of sludge, lower heating value of sludge on a dry basis, moisture content of biomass material, and calorific value of biomass material; S200. Based on the product parameters and raw material parameters, obtain the target value for sludge dewatering and the mixing ratio of dewatered sludge to biomass materials. Using the mixing ratio in S200 as the standard, obtain the relationship curves between the particle size of sludge powder, the particle size of biomass powder and the physical properties of the product; S400. Based on the relationship curve, obtain the particle size of sludge powder and biomass powder when the physical properties of the product meet the set threshold.

2. The method according to claim 1, characterized in that, Also includes: The product manufacturing process; the manufacturing process includes: A100: After the raw sludge is treated to the dewatering target value through the dewatering process, it is then crushed to the sludge powder particle size in S400 through the crushing process to obtain sludge powder. Biomass materials are pulverized to the biomass powder particle size in S400 through a pulverizing process to obtain biomass powder. A200, sludge powder, and biomass powder are processed into fuel products through a molding process.

3. The method according to claim 2, characterized in that, The dewatering process includes: after removing solid impurities from the raw sludge, it is first subjected to cell wall breaking treatment, and then to pressure filtration treatment; the dewatering target value is that the moisture content of the sludge is 45%-55%.

4. The method according to claim 3, characterized in that, When the sludge has a moisture content of 50%, its calorific value is 500-800 kcal / kg; when the biomass material has a moisture content of ≤20%, its calorific value is ≥3500 kcal / kg.

5. The method according to claim 1, characterized in that, When mixed, biomass materials account for 50%-70% by weight.

6. The method according to claim 1, characterized in that, The biomass materials include: wood or bamboo.

7. The method according to any one of claims 2-6, characterized in that, The A100 includes: Raw sludge is crushed to obtain sludge particles; Biomass materials are crushed to obtain biomass pellets; The sludge particles and biomass particles are mixed according to the mixing ratio in S200, and then crushed to obtain mixed powder.

8. The method according to claim 7, characterized in that, The output particle size of the crushing process is ≤5cm, the output particle size of the pulverizing process is ≤1mm, and the rotation speed of the mixing process is 30-50r / min.

9. The method according to claim 7, characterized in that, The rotation speed of the pulverizing process is 1200-1500 r / min.

10. The method according to claim 7, characterized in that, The temperature of the molding process is 70-90℃, and the extrusion pressure is 8-12MPa.