Manufacturing method of sludge-biomass fuel rod

Abstract

The invention relates to a manufacturing method of a sludge-biomass fuel rod. The manufacturing method comprises the following steps: S1, sludge pretreatment: dehydrating sludge; s2, sludge crushing treatment: performing crushing treatment on the dewatered sludge to obtain sludge particles with the particle size of less than or equal to 3mm; s3, sludge and biomass are mixed, wherein the sludge particles obtained in the step S2 and biomass particles are stirred and mixed according to the mass ratio of (10-90): (90-10), and a sludge-biomass forming raw material is obtained; s4, sludge-biomass raw material extrusion forming: performing extrusion forming on the sludge-biomass forming raw material obtained in the step S3 to obtain the sludge-biomass fuel rod. Compared with the prior art, the prepared sludge-biomass fuel rod has better combustion characteristics and stability. The sludge can play a bonding role in the fuel rod forming process, a compact body structure is conveniently formed, and forming is convenient; and the biomass is beneficial to improving the combustion characteristic of the fuel rod.

Description

Technical Field

[0001] The present invention relates to the technical field of biomass fuel technology and sludge resource utilization, in particular to a method for preparing sludge-biomass fuel rods. Background Art

[0002] Biomass, the world's fourth largest energy source, is abundant, readily available, and environmentally friendly, offering low-carbon, environmental benefits. my country, a major agricultural country, boasts abundant biomass resources from a wide variety of sources, including wheat straw, corn stalks, and some industrial organic waste. Therefore, the development of this clean, green, renewable fuel is of great significance.

[0003] Sludge generally refers to the by-product of sewage treatment plants during sewage purification. It is a complex, heterogeneous body composed of organic debris, bacterial cells, inorganic particles, colloids, and other substances, and poses considerable environmental hazards. The purpose of sludge treatment is to achieve volume reduction, harmlessness, and resource utilization. Currently, the more mature sludge treatment methods include land use, landfill, and incineration. Incineration is the process of fully burning the combustible materials in the sludge at high temperatures, which can effectively reduce the volume and weight of the sludge. The high volume and weight reduction rates, faster processing speed, and more thorough harmless treatment have made incineration the mainstream sludge disposal method in China. After initial treatment, the moisture content of the sludge discharged from the sewage treatment plant is always above 80%, which does not meet the incineration requirement of less than 67.7%. Therefore, the sludge needs to be further treated to facilitate subsequent incineration disposal.

[0004] CN116062962A discloses a method and system for mechanical sludge dehydration coupled with thermal drying and incineration. This system mechanically dehydrates wet sludge and uses the high-temperature flue gas generated by sludge fluidized bed incineration as a heat source for thermal drying. The system ultimately produces dried sludge with a moisture content ranging from 20% to 40%. While this system reduces sludge drying energy consumption to a certain extent, the resulting dried sludge has a wide range of moisture contents. For moisture contents above 30%, auxiliary fuel must be added to the fluidized bed incinerator, increasing costs. Furthermore, the sludge inevitably produces odor during the drying process, impacting the workshop and production area environment and posing environmental risks to the company and its surrounding areas.

[0005] CN101525209A discloses a sludge mechanical dehydration and semi-drying system. This system uses mechanical pressure to dehydrate chemically modified sludge, reducing it from a moisture content of approximately 85% to a semi-dried state of approximately 40%. This system is compact, low-cost, and highly mechanized, but the moisture content of the treated sludge remains relatively high, making it unsuitable for direct incineration.

[0006] CN110551549A discloses a device and method for preparing sludge-biomass pellet fuel rods, which mix sludge and biomass to form fuel rods. CN115074163A discloses an energy-intensive sludge fuel rod and its preparation method, which uses sludge as the primary raw material. However, both patents involve the use of heat sources to dry the sludge and fuel rods, resulting in increased energy consumption.

[0007] Patent CN105038894B discloses a sludge-biomass briquette fuel. The raw materials for the briquette fuel are sludge pellets and straw powder in a mass ratio of 2:10 to 10:10. The preparation method involves extruding sludge to produce sludge pellets with a particle size of 2 to 4 cm. The sludge pellets are then mixed with straw powder in a mass ratio of 2:10 to 10:10. Finally, the mixture is fed into a molding machine for compression molding to produce the sludge-biomass briquette fuel. This technology requires flocculation with an aluminum-based flocculant and dehydration and solidification steps, which increases sludge pretreatment costs. Furthermore, the large particle size of the sludge raw material increases the risk of equipment clogging.

[0008] In order to achieve the reduction, stabilization, harmlessness and resource utilization of sludge treatment and to efficiently prepare sludge-biomass fuel rods, it is necessary to propose a sludge-biomass fuel rod preparation process. Summary of the Invention

[0009] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a method for producing sludge-biomass fuel rods, which can effectively reduce the moisture content of sludge, improve the sludge combustion efficiency, and achieve sludge reduction, stabilization, harmlessness, resource treatment and efficient utilization of biomass energy.

[0010] The object of the present invention can be achieved by the following technical solutions: A method for producing a sludge-biomass fuel rod, comprising the following steps: A method for producing a sludge-biomass fuel rod, characterized in that it comprises the following steps: S1: Sludge pretreatment: dewatering the sludge; S2: Sludge crushing treatment: crush the dehydrated sludge to obtain sludge particles with a particle size of ≤3mm; S3: Sludge and biomass mixing treatment: The sludge particles obtained in step S2 are mixed with the biomass particles in a mass ratio of (10-90): (90-10) to obtain a sludge-biomass molding raw material; S4: Sludge-biomass raw material extrusion molding: The sludge-biomass molding raw material obtained in step S3 is extruded to obtain a sludge-biomass fuel rod.

[0011] Furthermore, the sludge before dehydration in step S1 is domestic sludge with a moisture content of 80% to 90%, and a filter press is used to perform mechanical deep dehydration to obtain a sludge raw material with a moisture content of 55% to 60%.

[0012] Furthermore, the wastewater generated by filter pressing is directly recycled to the sewage treatment plant for disposal.

[0013] Furthermore, the sludge crushing treatment in step S2 refers to sending the sludge raw material into a sludge crusher for crushing treatment.

[0014] Furthermore, the biomass particles in step S3 refer to biomass including crushed wood chips, straw, and waste plastics, and the particle size of the biomass particles ranges from 0.4 mm to 2 mm.

[0015] Furthermore, in step S3, the sludge particles and the biomass particles are in a mass ratio of (30-40): (70-60).

[0016] Furthermore, the extrusion molding in step S4 is performed in a biomass pellet machine.

[0017] Furthermore, the diameter of the sludge-biomass fuel rod obtained in step S4 is controlled to be 8 mm to 10 mm, the length is ≤ 6 cm, and it is cylindrical.

[0018] Furthermore, the calorific value of the sludge-biomass fuel rod can reach up to 3472 kcal / kg, with a moisture content of ≤10%, and can be directly burned as fuel.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. The sludge-biomass fuel rod production process of the present invention is rationally designed, the production process is simple and scientific, sludge dehydration is carried out with low energy consumption, cost is saved, and sludge resource utilization is realized efficiently.

[0020] 2. The present invention first dehydrates the sludge to a moisture content of about 55%, and then crushes it in a sludge crusher. The particle size of the crushed sludge is ≤3mm. The biomass particles are solid wood chips, straw, waste plastics, etc. with a particle size range of 0.4mm~2mm. Since the particle size of the sludge particles and biomass particles is relatively low, equipment blockage, abnormal noise and other faults can be avoided during the entire preparation process of the sludge-biomass fuel rods. After the biomass particles are mixed and extruded with the sludge particles, on the one hand, the moisture content of the sludge can be further reduced, which is beneficial for subsequent combustion disposal; on the other hand, in the sludge-biomass fuel rods prepared by the present invention, the biomass particles and the sludge are evenly mixed and entangled, so that the volatile matter in the biomass particles can be quickly released and burned during the combustion process, and promote the combustion of the combustible matter in the sludge particles. Therefore, compared with pure sludge fuel rods, the fuel rods prepared by the process of the present invention have better combustion performance.

[0021] 3. According to classical combustion theory, self-sustaining combustion can be achieved when the calorific value of the fuel exceeds 800 kcal / kg. According to the process of the present invention, by controlling the moisture content of the sludge, as well as the dosage ratio and particle size of the sludge particles and biomass particles, the calorific value of the prepared sludge-biomass fuel rods is greater than 800 kcal / kg. No other auxiliary agents need to be added to burn, thereby realizing the treatment and resource utilization of the sludge.

[0022] 4. In the process of preparing fuel rods, the present invention only mechanically dehydrates the sludge at room temperature without thermal drying of the sludge, which can effectively reduce the odor caused by the decomposition of organic matter in the sludge at high temperature to produce malodorous gases such as hydrogen sulfide and ammonia. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a step diagram of the present invention; Figure 2 This is a process flow chart for preparing the sludge-biomass fuel rods of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] The following is a detailed description of the invention through specific examples. Unless otherwise specified, the raw materials and equipment involved in the invention are all commercially available raw materials and equipment commonly used in the art.

[0026] Example 1: like Figure 1-2 As shown, the sludge-biomass fuel rod production process is: S1. Sludge pretreatment: The domestic sludge with a moisture content of 80% to 90% is subjected to mechanical deep dehydration using a plate and frame filter press to obtain sludge raw materials with a moisture content of 55% to 60%; S2. Sludge crushing treatment: The sludge raw material dehydrated in step S1 is fed into a sludge crusher with a driving power of 22 kW and a processing capacity of 2 t / h for crushing treatment to obtain sludge particles with a particle size of ≤3 mm; S3, sludge and biomass mixing treatment: the sludge particles obtained in step S2 and the biomass particles are fed into a double-screw mixer (screw blades; rotation speed 30-40 r / min; processing capacity 2 t / h) at a mass ratio of 30:70 for mixing to obtain sludge-biomass molding raw materials; the biomass particles are wood chip particles with a particle size range of 0.4 mm to 2 mm; S4. Sludge-biomass raw material extrusion molding: The sludge-biomass molding raw material obtained in step S3 is fed into a biomass pelletizer for extrusion molding to produce sludge-biomass fuel rods. The biomass pelletizer is a roller-type molding machine with a main engine power of 132 kW and an extrusion speed of 30 kg / min. The sludge-biomass fuel rods are cylindrical in shape with a diameter of 8 mm to 10 mm and a length of 3 cm to 6 cm.

[0027] Example 2 The production process of sludge-biomass fuel rods is as follows: S1. Sludge pretreatment: The domestic sludge with a moisture content of 80% to 90% is subjected to mechanical deep dehydration using a plate and frame filter press to obtain sludge raw materials with a moisture content of 55% to 60%; S2. Sludge crushing treatment: The sludge raw material dehydrated in step S1 is fed into a sludge crusher with a driving power of 22 kW and a processing capacity of 2 t / h for crushing treatment to obtain sludge particles with a particle size of ≤3 mm; S3. Sludge and biomass mixing treatment: The sludge particles obtained in step S2 and the biomass particles are fed into a double-screw mixer (screw blades; rotation speed 30-40 r / min; processing capacity 2 t / h) at a mass ratio of 40:60 for mixing to obtain a sludge-biomass molding raw material; the biomass particles are wood chip particles with a particle size range of 0.4 mm to 2 mm; S4. Sludge-biomass raw material extrusion molding: The sludge-biomass molding raw material obtained in step S3 is fed into a biomass pelletizer for extrusion molding to produce sludge-biomass fuel rods. The biomass pelletizer is a roller-type molding machine with a main engine power of 132 kW and an extrusion speed of 30 kg / min. The sludge-biomass fuel rods are cylindrical in shape with a diameter of 8 mm to 10 mm and a length of 3 cm to 6 cm.

[0028] Comparative Example 1 The production process of sludge-biomass fuel rods is as follows: S1. Sludge pretreatment: The domestic sludge with a moisture content of 80% to 90% is subjected to mechanical deep dehydration using a plate and frame filter press to obtain sludge raw materials with a moisture content of 55% to 60%; S2, sludge crushing treatment: the sludge raw material dehydrated in step S1 is squeezed to obtain sludge particles with a particle size of 2 to 4 cm; S3, sludge and biomass mixing treatment: The sludge particles obtained in step S2 and sawdust particles (0.5-2 cm) are fed into a double-screw mixer (spiral blades; rotation speed 30-40 r / min; processing capacity 2 t / h) at a mass ratio of 30:70 for mixing to obtain a sludge-biomass molding raw material; S4. Sludge-biomass raw material extrusion molding: The sludge-biomass molding raw material obtained in step S3 is fed into a biomass pelletizer for extrusion molding to produce sludge-biomass fuel rods. The biomass pelletizer is a roller-type molding machine with a main engine power of 132 kW and an extrusion speed of 30 kg / min. The sludge-biomass fuel rods are cylindrical in shape, with a diameter of 8 mm to 10 mm and a length of 3 cm to 4 cm.

[0029] Comparative Example 2 The production process of sludge-biomass fuel rods is as follows: S1. Sludge pretreatment: The domestic sludge with a moisture content of 80% to 90% is subjected to mechanical deep dehydration using a plate and frame filter press to obtain sludge raw materials with a moisture content of 55% to 60%; S2, sludge crushing treatment: the sludge raw material dehydrated in step S1 is squeezed to obtain sludge particles with a particle size of 2 to 4 cm; S3, sludge and biomass mixing treatment: The sludge particles obtained in step S2 and sawdust particles (0.5-2 cm) are fed into a double-screw mixer (spiral blades; rotation speed 30-40 r / min; processing capacity 2 t / h) at a mass ratio of 40:60 for mixing to obtain a sludge-biomass molding raw material; S4. Sludge-biomass raw material extrusion molding: The sludge-biomass molding raw material obtained in step S3 is fed into a biomass pelletizer for extrusion molding to produce sludge-biomass fuel rods. The biomass pelletizer is a roller-type molding machine with a main engine power of 132 kW and an extrusion speed of 30 kg / min. The sludge-biomass fuel rods are cylindrical in shape, with a diameter of 8 mm to 10 mm and a length of 3 cm to 4 cm.

[0030] The fuel rods prepared in Examples 1-2 and Comparative Examples 1-2 were uniformly subjected to performance tests, including lower calorific value according to GB / T-30727-2014, moisture content according to GB / T-28733-2012, and ash content after combustion according to GB / T-28731-2012. The results are shown in Table 1.

[0031] Table 1 From Table 1 we can see that: Comparing Example 1-2 with Comparative Example 1-2, it can be seen that the fuel rods prepared in Example 1-2 of the present application have a higher calorific value and a lower moisture content. The sludge-biomass fuel rods prepared by the present invention can achieve self-sustaining combustion and be directly burned and utilized as fuel, thereby realizing the resource utilization of sludge; and the moisture content of the sludge that has not undergone thermal drying treatment is still effectively reduced, thereby achieving sludge reduction and low-energy disposal. The low calorific value of the fuel rods prepared with a sludge to sawdust mass ratio of 40:60 can reach 3472kcal / kg, so a sludge to sawdust ratio of 40:60 is the optimal ratio for preparing fuel rods, which ensures high combustion performance while also ensuring a high sludge disposal volume. The particle size of the mixed sludge and biomass in Comparative Example 1-2 exceeds the scope of the present invention. It can be seen that its effect is not as good as that of the present invention.

[0032] Those skilled in the art will appreciate that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for producing sludge-biomass fuel rods, characterized in that: The following steps are involved: S1: Sludge pretreatment: dewatering the sludge; S2: Sludge crushing treatment: crush the dehydrated sludge to obtain sludge particles with a particle size of ≤3mm; S3: Sludge and biomass mixing treatment: The sludge particles obtained in step S2 are mixed with the biomass particles in a mass ratio of (10-90): (90-10) to obtain a sludge-biomass molding raw material; S4: Sludge-biomass raw material extrusion molding: The sludge-biomass molding raw material obtained in step S3 is extruded to obtain a sludge-biomass fuel rod.

2. The method for producing sludge-biomass fuel rods according to claim 1, characterized in that: The sludge before dehydration in step S1 is domestic sludge with a moisture content of 80% to 90%. A filter press is used to perform mechanical deep dehydration to obtain a sludge raw material with a moisture content of 55% to 60%.

3. The method for producing sludge-biomass fuel rods according to claim 2, characterized in that: The wastewater generated by filtration is directly recycled to the sewage treatment plant for disposal.

4. The method for producing sludge-biomass fuel rods according to claim 1, characterized in that: The sludge crushing process in step S2 refers to sending the sludge raw material into a sludge crusher for crushing.

5. The method for producing sludge-biomass fuel rods according to claim 1, characterized in that: The biomass particles in step S3 refer to biomass including crushed wood chips, straw, and waste plastics, and the particle size of the biomass particles ranges from 0.4 mm to 2 mm.

6. The method for producing sludge-biomass fuel rods according to claim 1, characterized in that: In step S3, the sludge particles and biomass particles are in a mass ratio of (30-40): (70-60).

7. The method for producing sludge-biomass fuel rods according to claim 1, characterized in that: The extrusion molding in step S4 is performed in a biomass pellet machine.

8. The method for producing sludge-biomass fuel rods according to claim 1, characterized in that: The diameter of the sludge-biomass fuel rod obtained in step S4 is controlled to be 8 mm to 10 mm, the length is ≤ 6 cm, and it is cylindrical.

9. The method for producing sludge-biomass fuel rods according to claim 1 or 8, characterized in that: The calorific value of the sludge-biomass fuel rod can reach up to 3472 kcal / kg, the moisture content is ≤10%, and it can be directly burned as fuel.

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