A sludge cyclone pyrolysis apparatus and method

Abstract

The application discloses a cyclone pyrolysis device and method, wherein activated sludge particles are blown into a cyclone pyrolysis device by carrier gas nitrogen, the cyclone pyrolysis device is heated by a pyrolysis furnace, the pyrolysis temperature is controlled to be 600-1000 DEG C, the pyrolysis time is 1.5-2h, the nitrogen gas inlet speed is adjusted so that the sludge particles can keep suspended movement in the cyclone pyrolysis device, and meanwhile, the self-revolution-suspended recirculation coupling pyrolysis of the particles is realized; after the pyrolysis is completed, the nitrogen gas flow rate is adjusted, so that the solid product, pyrolysis gas and tar are separated by cyclone in the cyclone pyrolysis device and then discharged from the cyclone pyrolysis device for collection; the cyclone pyrolysis device and method can realize sufficient and efficient pyrolysis of sludge particles, have low process energy consumption, and can obtain sludge activated carbon with strong adsorption and pure pyrolysis gas and tar.

Description

Technical Field

[0001] This invention relates to the field of sludge resource utilization technology, specifically to a sludge cyclone pyrolysis device and method. Background Technology

[0002] In recent years, with the rapid improvement of my country's wastewater treatment capacity, the amount of sludge has also increased significantly. In 2019, the amount of urban wet sludge produced was close to 50 million tons, nearly double that of 2010, with an average compound annual growth rate of 7.3% over the 10 years from 2010 to 2019. Wastewater treatment is an industry that cannot be ignored in achieving carbon emission control, and the sludge treatment and disposal process is a crucial link affecting the carbon emissions of the wastewater treatment industry.

[0003] Resource utilization of sewage sludge is crucial for sludge disposal. Currently, my country's sludge resource utilization mainly includes land application, building materials, and sludge digestion capacity. However, sludge not only contains pathogens and parasites, but also heavy metals such as zinc, copper, and mercury, as well as some persistent organic pollutants. If these harmful components are not properly treated, they will cause significant harm to the natural environment and human health.

[0004] Sludge pyrolysis technology has attracted much attention due to its advantages of "volume reduction, harmlessness, and resource recovery". Pyrolysis can significantly reduce sludge volume, prevent dioxin generation, solidify heavy metals, reduce costs and pollution, and has a wide range of applications.

[0005] Currently used sludge pyrolysis devices, such as fixed-bed reactors, plasma reactors, and tubular furnaces, often suffer from problems such as large cylinder diameters, difficulty in sealing, poor pyrolysis effect, low pyrolysis efficiency, high dust content at the pyrolysis gas outlet, and poor quality of pyrolysis products.

[0006] Therefore, achieving efficient pyrolysis of sludge and improving the quality of pyrolysis products is the key to realizing the "reduction, harmlessness, and resource utilization" of sludge treatment and disposal.

[0007] CN205773992U discloses an apparatus for producing biochar by pyrolysis of sludge. The sludge raw material enters a stainless steel pyrolysis furnace through an air inlet device and a feeding device, and is pyrolyzed in a nitrogen atmosphere provided by the air inlet device. The apparatus has a simple structure and is easy to operate, but after the sludge raw material enters the pyrolysis furnace, it requires a long pyrolysis time and suffers from problems such as insufficient pyrolysis and poor pyrolysis efficiency.

[0008] CN110066083A discloses a sludge pyrolysis method, which involves adding a heat carrier, quartz sand or solid ceramic balls, to the pyrolysis reactor to conduct heat to the sludge. Simultaneously, spiral blades and stirring blades are used to mix the sludge and the heat carrier, thereby achieving complete pyrolysis of the sludge and recovering the pyrolysis products. However, the addition of the heat carrier increases the process cost, and there are problems such as difficulty in separating the heat carrier from the pyrolysis coke. The spiral blades and stirring blades in the pyrolysis reactor increase the energy consumption and operational complexity of the equipment.

[0009] CN206278920U discloses a rotary pyrolysis system for municipal sewage sludge. This system achieves rotary pyrolysis of the sludge by incorporating a built-in tray and combustion chamber within the pyrolysis furnace, while simultaneously activating the pyrolyzed activated carbon using a fluidized bed. However, the internal structure of this pyrolysis furnace is relatively complex, making it difficult to achieve deep pyrolysis of the sludge particles and to completely remove tar from the activated carbon, resulting in low-quality activated carbon.

[0010] CN111153576A discloses a rotary oily sludge treatment system and method. The system includes a feeding screw conveyor, a rotary pyrolysis furnace, and a discharging screw conveyor. The rotary pyrolysis furnace, along its length, comprises five sections: a feeding section, a first transmission section, a pyrolysis section, a second transmission section, and a discharging section. Multiple fixed lifting plates and multiple stirring chains within the pyrolysis chamber agitate the sludge. The pyrolysis furnace is used for heating outside the chamber. The device pyrolyzes the sludge inside the furnace chamber through rotation. However, this sludge pyrolysis system is cumbersome, with a complex overall structure and complicated operation procedures. Furthermore, the sludge pyrolysis efficiency is low due to the limitation on the sludge filling rate of the pyrolysis furnace cylinder (15-20%), and the closed nature of the furnace prevents continuous pyrolysis, also contributing to low efficiency. Summary of the Invention

[0011] To address the shortcomings of existing sludge pyrolysis technologies, this invention provides a sludge cyclone pyrolysis apparatus and method that offers high pyrolysis efficiency and produces high-quality sludge activated carbon, pyrolysis gas, and tar.

[0012] To achieve the above objectives, the present invention adopts the following technical solution:

[0013] The first aspect of the present invention is to provide a sludge cyclone pyrolysis method, comprising the following steps:

[0014] S1. Activated sludge feeding: The activated sludge particles are carried into the cyclone pyrolyzer along the tangential direction of the cyclone pyrolyzer by a nitrogen gas flow;

[0015] S2. Heating of the cyclone pyrolyzer: The cyclone pyrolyzer is heated by a heating device so that the temperature inside the cyclone pyrolyzer is 600℃~1000℃;

[0016] S3. Sludge cyclone pyrolysis: After the activated sludge particles enter the cyclone pyrolyzer tangentially, the nitrogen gas inlet speed is adjusted so that the activated sludge particles remain in suspension in the cyclone pyrolyzer while realizing the particle self-rotation-suspension recirculation coupled pyrolysis.

[0017] S4. Cyclone separation and collection of pyrolysis products: After pyrolysis is completed, the nitrogen gas inlet speed is gradually adjusted to 0, so that the solid products of sludge pyrolysis flow to the bottom of the cyclone pyrolyzer for collection, and the pyrolysis gas and pyrolysis tar are discharged from the top of the cyclone pyrolyzer for collection.

[0018] This invention uses nitrogen as the carrier gas (the nitrogen inlet velocity is achieved by controlling the nitrogen inlet flow rate at the inlet, where nitrogen inlet velocity = nitrogen inlet flow rate / inlet cross-sectional area). While maintaining an inert atmosphere, a swirling flow field is formed by the tangential blowing of nitrogen. The swirling flow and tangential velocity gradient generated by the swirling flow field continuously renew the heated reaction layer on the surface of the sludge particles, achieving efficient layer-by-layer pyrolysis of the sludge particles. At the same time, the tar and pyrolysis gas produced by pyrolysis also migrate from the particle channels to the particle surface and are blown out by nitrogen. After pyrolysis, by adjusting the nitrogen flow rate, the solid phase products of pyrolysis flow to the bottom of the swirling pyrolyzer for collection, while the pyrolysis gas and tar are discharged from the top of the swirling pyrolyzer for collection, resulting in pure pyrolysis gas and tar.

[0019] According to an embodiment of the present invention, in step S1, the sludge activation uses a 1.5 mol / L to 2 mol / L potassium hydroxide solution as the activating agent, and the sludge is immersed and activated for 20 to 30 hours.

[0020] According to an embodiment of the present invention, in step S1, the particle size of the sludge particles is 1-5 mm.

[0021] According to an embodiment of the present invention, the nitrogen intake volume in steps S1 and S2 is 0.6 m³. 3 / h~1.2m 3 / h, air inlet cross-sectional area is 100mm² 2 ~500mm 2 .

[0022] This invention controls the nitrogen gas flow rate by controlling the nitrogen intake volume, so that the sludge particles are in a high-speed rotating swirling field during pyrolysis. The rotation speed of the sludge particles can reach tens of thousands of revolutions per minute. The swirling flow and tangential velocity gradient generated by the swirling field continuously renew the heated reaction layer on the surface of the sludge particles, achieving efficient layer-by-layer pyrolysis of the sludge particles. At the same time, by utilizing the high-speed shear force and mechanical stripping effect of the sludge in the swirling field, the centrifugal removal of pyrolysis gaseous products and tar in the particles is enhanced, achieving a more thorough separation of the three-phase products after pyrolysis.

[0023] According to an embodiment of the present invention, the heating rate of the cyclone pyrolyzer in step S2 is controlled at 5°C / min to 10°C / min.

[0024] According to an embodiment of the present invention, the cyclone pyrolysis time in step S3 is 1.5 to 2 hours.

[0025] A second aspect of the present invention is to provide a sludge cyclone pyrolysis apparatus, comprising:

[0026] A pyrolysis furnace includes a furnace shell and a heating chamber formed within the furnace shell. The upper side wall of the furnace shell is provided with a pyrolysis furnace inlet, the top of the furnace shell is provided with a pyrolysis furnace top outlet, and the bottom of the furnace shell is provided with a pyrolysis furnace bottom outlet. The pyrolysis furnace is also equipped with a pyrolysis furnace control unit for controlling the pyrolysis process.

[0027] A cyclone pyrolyzer has a cyclone pyrolysis chamber located within the heating chamber of a pyrolysis furnace. The cyclone pyrolysis chamber has an overflow pipe at its top and an underflow pipe at its bottom, with a tangential inlet located on its side wall near the top. The underflow pipe extends from the bottom outlet of the pyrolysis furnace, the overflow pipe extends from the top outlet of the pyrolysis furnace, and the tangential inlet extends from the inlet of the pyrolysis furnace.

[0028] The feeding assembly includes a feed pipe and a feed funnel whose bottom is connected to the top wall of the feed pipe; wherein, the feed pipe is sealed to a tangential inlet for the introduction of nitrogen gas flow into the cyclone pyrolyzer and for the feeding of activated sludge, and the feed funnel is used to store activated sludge particles.

[0029] An oil-gas separator is sealed to the outlet end of the overflow pipe via a pipeline and is used to receive and separate tar and pyrolysis gas generated by pyrolysis.

[0030] A storage hopper is located at the lower end of the underflow pipe and is sealed to the underflow pipe for collecting solid products generated by pyrolysis.

[0031] According to an embodiment of the present invention, the cyclone pyrolyzer is made of quartz.

[0032] According to an embodiment of the present invention, the upper half of the cyclone pyrolysis chamber is a columnar structure, and the lower half is a tapered conical structure.

[0033] The cyclone pyrolysis chamber of this invention adopts this structure (the upper part is a columnar structure, and the lower part is a conical structure). During the pyrolysis process, the sludge particles can enhance the swirling flow at the column-cone interface. Under the action of the rotating airflow, the sludge particles undergo high-speed self-revolution-suspension recirculation coupled motion along the wall of the cyclone pyrolysis unit at the column-cone interface, so that the sludge particles can achieve more complete and efficient pyrolysis. After pyrolysis, the pyrolysis products can be effectively separated in the cyclone pyrolysis unit. The pyrolysis reaction of sludge particles and the separation of pyrolysis products are carried out in the same device. The pyrolysis gas and pyrolysis tar are discharged from the top of the cyclone pyrolysis unit and enter the oil-gas separator, where they are further separated to obtain pure pyrolysis tar and pyrolysis gas.

[0034] According to an embodiment of the present invention, the pyrolysis furnace is a vertical pyrolysis furnace, and the shape of its heating chamber matches the outer surface of the cyclone pyrolyzer.

[0035] This invention uses a vertical pyrolysis furnace to heat the cyclone pyrolyzer, which can provide a uniform pyrolysis space and heat preservation environment for the sludge cyclone pyrolysis process, which is beneficial to the subsequent separation of pyrolysis products; the shape of the heating chamber of the vertical pyrolysis furnace matches the cyclone pyrolyzer, ensuring that there are no dead angles in the heating.

[0036] Compared with the prior art, the present invention has at least the following beneficial effects:

[0037] 1. This invention uses nitrogen gas as the carrier gas and utilizes the self-rotation-suspension-recirculation coupled motion of sludge particles in the swirling field. Combined with the particle pyrolysis unreacted shrinkage core model, it accelerates the real-time renewal of the mass and heat transfer surface of the particle. Convective heat transfer and radiative heat transfer continuously transfer heat to the renewed particle surface. While the reaction interface of the particle surface can be renewed in real time, the residence time in the swirling reactor is also increased, realizing the full and efficient pyrolysis of sludge particles.

[0038] 2. This invention utilizes the high-speed shear force and mechanical stripping effect of sludge in a swirling field to enhance the centrifugal removal of pyrolysis gaseous products and tar from particles. Compared with traditional pyrolysis processes, the pyrolysis of sludge and the separation of pyrolysis products are carried out in the same device (swirling pyrolyzer) in this invention, achieving a more thorough separation of the three-phase products after pyrolysis. In addition, the improved sludge dewatering and pyrolysis efficiency and the savings in separation equipment correspondingly reduce process energy consumption.

[0039] 3. The three-phase products after pyrolysis of this invention include activated carbon, which can be used as an adsorbent; gaseous products rich in hydrogen, which can be used to produce high-grade gaseous fuel or syngas; and tar, which can also be used as a potential energy product. This invention can alleviate environmental pollution problems while providing clean energy, and is an effective way to utilize sludge resources. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the rotary pyrolysis apparatus of the present invention.

[0041] Figure 2 This is a schematic diagram of the pyrolysis furnace of the present invention.

[0042] Figure 3 This is a schematic diagram of the cyclone pyrolysis device of the present invention.

[0043] Figure 4 A process flow diagram for preparing activated carbon and hydrogen-rich gas by pyrolysis of municipal sludge according to a preferred embodiment of the present invention.

[0044] In the diagram: 10-Pyrolysis furnace; 11-Furnace shell; 12-Heating chamber; 13-Pyrolysis furnace inlet; 14-Pyrolysis furnace top outlet; 15-Pyrolysis furnace bottom outlet; 16-Pyrolysis furnace control unit;

[0045] 20-Swirl pyrolyzer; 21-Swirl pyrolysis chamber; 22-Overflow pipe; 23-Underflow pipe; 24-Tangential inlet;

[0046] 30 - Feed assembly; 31 - Feed pipe; 32 - Feed funnel;

[0047] 40 - Oil-gas separator;

[0048] 50 - Storage hopper;

[0049] 61-Gravity settling tank; 62-Plate and frame filter press; 63-Sludge crusher; 64-Pulsating airflow generator; 65-Pipeline heater; 66-First-stage cyclone dewatering unit; 67-Vibrating drying column; 68-Second-stage cyclone dewatering unit; 69-Sludge activation tank; 610-Water-air separator Detailed Implementation

[0050] The present invention will be further described in detail below with reference to specific embodiments and examples. It should be understood that the following examples are for further illustration only and should not be construed as limiting the scope of protection of the present invention. Non-substantial improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention. Test methods in the following examples that do not specify specific conditions are generally performed under conventional conditions or as recommended by the manufacturer. Unless otherwise stated, all percentages and parts are by weight.

[0051] Existing sludge pyrolysis methods are difficult to achieve complete pyrolysis of the sludge particles, and the activated carbon products from the pyrolysis sludge contain pyrolysis tar, resulting in low quality of the pyrolysis products. In order to effectively solve the above technical problems, the present invention provides a sludge pyrolysis device and method with high pyrolysis efficiency, low process energy consumption, and effective utilization of sludge resources.

[0052] See Figures 1-3 The sludge cyclone pyrolysis device of the present invention includes

[0053] The pyrolysis furnace 10 includes a furnace shell 11 and a heating chamber 12 formed in the furnace shell 11. The upper side wall of the furnace shell 11 is provided with a pyrolysis furnace inlet 13, the top of the pyrolysis furnace is provided with a top outlet 14, and the bottom of the pyrolysis furnace is provided with a bottom outlet 15. The pyrolysis furnace 10 is also equipped with a pyrolysis furnace control unit 16 for controlling the pyrolysis process.

[0054] The cyclone pyrolyzer 20 has a cyclone pyrolysis chamber 21, which is located inside the heating chamber 12 of the pyrolysis furnace 10. An overflow pipe 22 is provided at the top of the cyclone pyrolysis chamber 21, and an underflow pipe 23 is provided at the bottom. A tangential inlet 24 is provided on the side wall of the chamber near the top. The overflow pipe 22 extends from the top outlet 14 of the pyrolysis furnace, the underflow pipe 23 extends from the bottom outlet 15 of the pyrolysis furnace, and the tangential inlet 24 extends from the inlet 13 of the pyrolysis furnace.

[0055] The feeding assembly 30 includes a feeding pipe 31 and a feeding funnel 32 whose bottom is connected to the top wall of the feeding pipe; wherein, the feeding pipe 31 is sealed to the tangential inlet 24 for the introduction of nitrogen gas flow into the cyclone pyrolyzer 20 and the feeding of activated sludge, and the feeding funnel 32 is used to store the activated sludge particles.

[0056] The oil-gas separator 40 is sealed to the outlet end of the overflow pipe 22 via a pipeline and is used to receive and separate the tar and pyrolysis gas produced by pyrolysis.

[0057] The storage hopper 50 is located at the lower end of the underflow pipe 23 and is sealed to the underflow pipe 23 for collecting solid products generated by pyrolysis.

[0058] In use, the activated sludge particles are stored in the feed funnel 32; nitrogen gas is introduced at the inlet of the feed pipe 31 (the nitrogen gas inlet speed of this invention is achieved by controlling the nitrogen gas inlet flow rate of the feed pipe, nitrogen gas inlet speed = nitrogen gas inlet flow rate / feed pipe cross-sectional area), and the sludge particles, under the action of the carrier nitrogen gas, enter the cyclone pyrolysis unit 20 tangentially through the feed pipe 31; the pyrolysis process is controlled by the pyrolysis furnace control unit 16; after the activated sludge particles enter the cyclone pyrolysis chamber 21 tangentially, the nitrogen gas flow rate is adjusted to make... The activated sludge particles remain suspended in the cyclone pyrolysis chamber 21, achieving a coupled pyrolysis of particle self-revolution and suspension recirculation. After pyrolysis, the nitrogen flow rate is gradually reduced to 0, causing the solid products to flow to the underflow pipe 23 at the bottom of the cyclone pyrolysis chamber 21 and finally be collected in the storage hopper 50. The pyrolysis gas and pyrolysis tar are discharged from the overflow pipe 22 at the top of the cyclone pyrolyzer 20 and enter the oil-gas separator 40. The pyrolysis gas and pyrolysis tar are further separated in the oil-gas separator 40, finally obtaining pure pyrolysis tar and pyrolysis gas.

[0059] Preferably, the cyclone pyrolyzer 20 is made of quartz material, which can withstand extremely high temperatures and is suitable for the high-temperature environment during the pyrolysis process.

[0060] Preferably, the upper half of the cyclone pyrolysis chamber 21 has a columnar structure, and the lower half has a tapered structure.

[0061] The cyclone pyrolysis chamber 21 of the cyclone pyrolysis unit 20 of this invention adopts this structure (the upper part is a columnar structure and the lower part is a conical structure). During the pyrolysis process, the sludge particles can enhance the swirling flow at the column-cone interface. Under the action of the rotating airflow, the sludge particles undergo high-speed self-revolution-suspension recirculation coupled motion along the wall of the cyclone pyrolysis unit at the column-cone interface, so that the sludge particles can be fully and efficiently pyrolyzed. After the pyrolysis is completed, the pyrolysis products can be effectively separated in the cyclone pyrolysis unit. The pyrolysis reaction of the sludge particles and the separation of the pyrolysis products are carried out in the same device. The pyrolysis gas and pyrolysis tar are discharged from the top of the cyclone pyrolysis unit and enter the oil-gas separator to obtain pure tar and pyrolysis gas.

[0062] Preferably, the pyrolysis furnace 10 is a vertical pyrolysis furnace, and the shape of its heating chamber 12 matches the outer surface of the cyclone pyrolyzer 20.

[0063] The present invention uses a vertical pyrolysis furnace to heat the cyclone pyrolyzer 20, which can provide a uniform pyrolysis space and heat preservation environment for the sludge cyclone pyrolysis process, which is beneficial to the subsequent separation of pyrolysis products; the shape of the heating chamber 12 of the vertical pyrolysis furnace matches the external shape of the cyclone pyrolyzer, ensuring that there are no dead angles in the heating.

[0064] The present invention also provides a sludge cyclone pyrolysis method, comprising the following steps:

[0065] S1. Activated sludge feeding: The activated sludge particles are carried into the cyclone pyrolyzer tangentially by a nitrogen gas flow;

[0066] S2. Heating of the cyclone pyrolyzer: The cyclone pyrolyzer is heated by a heating device to make the internal temperature of the cyclone pyrolyzer 600℃~1000℃;

[0067] S3. Sludge cyclone pyrolysis: After the activated sludge particles enter the cyclone pyrolyzer tangentially, the nitrogen gas inlet speed is adjusted so that the activated sludge particles remain in suspension in the cyclone pyrolyzer while realizing the particle self-rotation-suspension recirculation coupled pyrolysis.

[0068] S4. Cyclone separation and collection of pyrolysis products: After pyrolysis is completed, the nitrogen inlet speed is gradually adjusted to 0, so that the solid products of sludge pyrolysis flow to the bottom of the cyclone pyrolyzer for collection, while the pyrolysis gas and pyrolysis tar are discharged from the top of the cyclone pyrolyzer for collection.

[0069] This invention uses nitrogen as the carrier gas (the nitrogen inlet velocity is achieved by controlling the nitrogen inlet flow rate at the inlet, where nitrogen inlet velocity = nitrogen inlet flow rate / inlet cross-sectional area). While maintaining an inert atmosphere, a swirling flow field is formed by the tangential blowing of nitrogen. The swirling flow and tangential velocity gradient generated by the swirling flow field continuously renew the heated reaction layer on the surface of the sludge particles, achieving efficient layer-by-layer pyrolysis of the sludge particles. At the same time, the tar and pyrolysis gas produced by pyrolysis also migrate from the particle channels to the particle surface and are blown out by nitrogen. After pyrolysis, by adjusting the nitrogen flow rate, the solid phase products of pyrolysis flow to the bottom of the swirling pyrolyzer for collection, while the pyrolysis gas and tar are discharged from the top of the swirling pyrolyzer for collection, resulting in pure pyrolysis gas and tar.

[0070] Preferably, in step S1, the sludge activation uses a 1.5 mol / L to 2 mol / L potassium hydroxide solution as the activator, and the sludge is immersed and activated for 20 to 30 hours.

[0071] Preferably, in step S1, the particle size of the sludge particles is 1 to 5 mm.

[0072] Preferably, the nitrogen intake flow rate in steps S1 and S2 is 0.6 m³. 3 / h~1.2m 3 / h, air inlet cross-sectional area is 100mm² 2 ~500mm 2 .

[0073] This invention controls the nitrogen gas flow rate by controlling the nitrogen intake volume, so that the sludge particles are in a high-speed rotating swirling field during pyrolysis. The rotation speed of the sludge particles can reach tens of thousands of revolutions per minute. The swirling flow and tangential velocity gradient generated by the swirling field continuously renew the heated reaction layer on the surface of the sludge particles, achieving efficient layer-by-layer pyrolysis of the sludge particles. At the same time, by utilizing the high-speed shear force and mechanical stripping effect of the sludge in the swirling field, the centrifugal removal of pyrolysis gaseous products and tar in the particles is enhanced, achieving a more thorough separation of the three-phase products after pyrolysis.

[0074] Preferably, the heating rate of the cyclone pyrolyzer in step S2 is controlled at 5℃ / min to 10℃ / min.

[0075] According to an embodiment of the present invention, the cyclone pyrolysis time in step S3 is 1.5 to 2 hours (the pyrolysis time is calculated from the time the temperature reaches the pyrolysis temperature).

[0076] See Figure 4 A flow chart of a preferred embodiment of the present invention for the preparation of activated carbon and hydrogen-rich gas by pyrolysis of municipal sludge; as shown. Figure 4 As shown, municipal sludge is fed into a plate and frame filter press 62 for physical dewatering after passing through a gravity settling tank 61. Subsequently, it is crushed into 1-5mm sludge particles by a sludge crusher 63. A pulsating airflow generator 64 and a pipe heater 65 generate a 60°C pulsating airflow with sine and cosine waveforms. Under the action of this pulsating airflow, the sludge particles sequentially enter a primary cyclone dewatering unit 66, a vibrating drying column 67, and a secondary cyclone dewatering unit 68 for deep dewatering, ultimately achieving sludge drying and volume reduction. The sludge particles discharged from the underflow outlet of the secondary cyclone dewatering unit 68 enter a sludge activation tank 69, using a 1.5... A potassium hydroxide solution of mol / L to 2 mol / L is used as an activator to impregnate and activate the sludge for 20 to 30 hours. The waste gas discharged from the overflow port of the secondary cyclone dehydrator 68 enters the water-gas separator 610. The condensed water is collected from the bottom, and the overflow port sends the gas flow to the pulsating gas generator 64 for recycling. The activated sludge particles are stored in the feed funnel 32 of the cyclone pyrolysis device. Nitrogen gas is introduced at the inlet of the feed pipe 31. Under the action of the carrier gas nitrogen, the sludge particles enter the cyclone pyrolysis unit 20 through the feed pipe 31 located at the bottom of the feed funnel 32. The cross-sectional area of ​​the feed pipe 31 is 100 to 500 mm². 2 The nitrogen intake flow rate is adjusted to 0.6 m³ / s using the valve on the nitrogen storage tank. 3 / h~1.2m 3 The vertical pyrolysis furnace is controlled by the pyrolysis furnace control unit 16 to heat the cyclone pyrolysis unit 20 at a rate of 5℃ / min to 10℃ / min, a pyrolysis temperature of 600℃ to 1000℃, and a pyrolysis time of 1.5h to 2h. After the activated sludge particles enter the cyclone pyrolysis chamber 2 tangentially, the nitrogen inlet flow rate is adjusted to 0.6m³ / h. 3 / h~1.2m 3 The activated sludge particles remain suspended in the cyclone pyrolysis chamber 21, achieving a coupled pyrolysis of particle rotation and suspension recirculation. After pyrolysis, the nitrogen flow rate is gradually reduced to 0, allowing the solid products to flow through the underflow pipe 23 to the storage hopper 50, where they are finally collected. Pyrolysis gas and pyrolysis tar are discharged from the overflow pipe 22 at the top of the cyclone pyrolysis chamber 21 into the oil-gas separator 40, where they are further separated to obtain pure pyrolysis tar and pyrolysis gas. Multiple sets of the primary cyclone rotary dehydrator 66, the vibrating drying column 67, the secondary cyclone rotary dehydrator 68, and the cyclone pyrolysis device can be connected in parallel.

[0077] In a municipal sludge resource utilization device, the dewatered and dried sludge is subjected to pyrolysis treatment according to the method and device of the present invention. The specific operation process and effects are described as follows:

[0078] 1. Sources and properties of sludge

[0079] The municipal sludge used in the experiment of this invention was taken from the secondary sedimentation tank of a sewage treatment plant in Shanghai. Before the experiment, the sludge after plate and frame filter press was pretreated and its properties were measured. Table 1 shows the industrial analysis of the sludge; Table 2 shows the elemental analysis of the sludge; and Table 3 shows the specific surface area and pore size analysis of the sludge.

[0080] Table 1 Industrial Analysis of Sludge

[0081] sludge 63.2 55.9 42.8 1.01

[0082] Table 2 Elemental Analysis of Sludge (Dry Basis, %)

[0083] sludge 25.18 4.8535 31.855 4.34 0.966

[0084] Table 3. Specific Surface Area-Pore Size Analysis of Sludge

[0085]

[0086] 2. Preparation of activated carbon from sludge by pyrolysis

[0087] (1) Sample processing

[0088] After passing through gravity settling tank 61, municipal sludge is sent to plate and frame filter press 62 for physical dewatering, and then crushed into 1-5mm sludge particles by sludge crusher 63. Pulsating airflow generator 64 and pipeline heater 65 generate air into 60℃ pulsating airflow with sine and cosine waveforms. Under the action of this pulsating airflow, the sludge particles sequentially enter the first-stage cyclone dewatering tank 66, the vibrating drying column 67 and the second-stage cyclone dewatering tank 68 for deep dewatering, ultimately achieving sludge drying and volume reduction. The sludge particles discharged from the bottom outlet of the second-stage cyclone dewatering tank 68 enter the sludge activation tank 69, where a 2mol / L potassium hydroxide solution is used as the activator for soaking and activation for 24 hours before use.

[0089] (2) Preparation of activated carbon from sludge by cyclone pyrolysis

[0090] Example 1

[0091] S1. Activated sludge feeding: The activated sludge particles are stored in the feed funnel 32 of the hydrocyclone pyrolysis device; nitrogen gas is introduced at the inlet of the feed pipe 31, and the sludge particles enter the hydrocyclone pyrolyzer 20 through the feed pipe 31 under the action of the carrier gas nitrogen. The cross-sectional area of ​​the feed pipe is 100 mm². 2 The nitrogen intake flow rate is adjusted to 1m³ via the valve on the nitrogen storage tank. 3 / h;

[0092] S2. Heating of the cyclone pyrolyzer: The vertical pyrolyzer 20 is heated by the vertical pyrolyzer control unit 16, with the heating rate set to 5℃ / min, the pyrolysis temperature to 500℃, and the pyrolysis time to 2h.

[0093] S3. Sludge Cyclone Pyrolysis: After the activated sludge particles enter the cyclone pyrolysis chamber 21 tangentially, the nitrogen gas intake is controlled to be 1 m³ / s. 3 / h, so that the activated sludge particles remain suspended in the cyclone pyrolysis chamber 21 while realizing the particle's self-rotation-suspension recirculation coupled pyrolysis.

[0094] S4. Cyclone Separation and Collection of Pyrolysis Products: After pyrolysis, the nitrogen flow rate is gradually adjusted to 0, allowing the solid product (sludge activated carbon) to flow into the bottom storage hopper 50 through the underflow pipe 23. The pyrolysis gas and pyrolysis tar are discharged from the overflow pipe 22 at the top of the cyclone pyrolyzer 20 and enter the oil-gas separator 40, where they are further separated to obtain pure pyrolysis tar and pyrolysis gas. The specific surface area and pore size of the obtained sludge activated carbon are analyzed, and the data are shown in Table 4.

[0095] Example 2

[0096] S1. Activated sludge feeding: The activated sludge particles are stored in the feed funnel 32 of the hydrocyclone pyrolysis device; nitrogen gas is introduced at the inlet of the feed pipe 31, and the sludge particles enter the hydrocyclone pyrolyzer 20 through the feed pipe 31 under the action of the carrier gas nitrogen. The cross-sectional area of ​​the feed pipe is 100 mm². 2 The nitrogen intake flow rate is adjusted to 1m³ via the valve on the nitrogen storage tank. 3 / h;

[0097] S2. Heating of the cyclone pyrolyzer: The vertical pyrolyzer 20 is heated by the vertical pyrolyzer control unit 16, with the heating rate set to 5℃ / min, the pyrolysis temperature to 550℃, and the pyrolysis time to 2h.

[0098] S3. Sludge Cyclone Pyrolysis: After the activated sludge particles enter the cyclone pyrolysis chamber 21 tangentially, the nitrogen gas intake is controlled to be 1 m³ / s. 3 / h, so that the activated sludge particles remain suspended in the cyclone pyrolysis chamber 21 while realizing the particle's self-rotation-suspension recirculation coupled pyrolysis.

[0099] S4. Cyclone Separation and Collection of Pyrolysis Products: After pyrolysis, the nitrogen flow rate is gradually adjusted to 0, allowing the solid product (sludge activated carbon) to flow into the bottom storage hopper 50 through the underflow pipe 23. The pyrolysis gas and pyrolysis tar are discharged from the overflow pipe 22 at the top of the cyclone pyrolyzer 20 and enter the oil-gas separator 40, where they are further separated to obtain pure pyrolysis tar and pyrolysis gas. The specific surface area and pore size of the obtained sludge activated carbon are analyzed, and the data are shown in Table 4.

[0100] Example 3

[0101] S1. Activated sludge feeding: The activated sludge particles are stored in the feed funnel 32 of the hydrocyclone pyrolysis device; nitrogen gas is introduced at the inlet of the feed pipe 31, and the sludge particles enter the hydrocyclone pyrolyzer 20 through the feed pipe 31 under the action of the carrier gas nitrogen. The cross-sectional area of ​​the feed pipe is 100 mm². 2 The nitrogen intake flow rate is adjusted to 1m³ via the valve on the nitrogen storage tank. 3 / h;

[0102] S2. Heating of the cyclone pyrolyzer: The vertical pyrolyzer 20 is heated by the vertical pyrolyzer control unit 16, with the heating rate set to 5℃ / min, the pyrolysis temperature to 600℃, and the pyrolysis time to 2h.

[0103] S3. Sludge Cyclone Pyrolysis: After the activated sludge particles enter the cyclone pyrolysis chamber 21 tangentially, the nitrogen gas intake is controlled to be 1 m³ / s. 3 / h, so that the activated sludge particles remain suspended in the cyclone pyrolysis chamber 21 while realizing the particle's self-rotation-suspension recirculation coupled pyrolysis.

[0104] S4. Cyclone Separation and Collection of Pyrolysis Products: After pyrolysis, the nitrogen flow rate is gradually adjusted to 0, allowing the solid product (sludge activated carbon) to flow into the bottom storage hopper 50 through the underflow pipe 23. The pyrolysis gas and pyrolysis tar are discharged from the overflow pipe 22 at the top of the cyclone pyrolyzer 20 and enter the oil-gas separator 40, where they are further separated to obtain pure pyrolysis tar and pyrolysis gas. The specific surface area and pore size of the obtained sludge activated carbon are analyzed, and the data are shown in Table 4.

[0105] Example 4

[0106] S1. Activated sludge feeding: The activated sludge particles are stored in the feed funnel 32 of the hydrocyclone pyrolysis device; nitrogen gas is introduced at the inlet of the feed pipe 31, and the sludge particles enter the hydrocyclone pyrolyzer 20 through the feed pipe 31 under the action of the carrier gas nitrogen. The cross-sectional area of ​​the feed pipe is 100 mm². 2 The nitrogen intake flow rate is adjusted to 1m³ via the valve on the nitrogen storage tank. 3 / h;

[0107] S2. Heating of the cyclone pyrolyzer: The vertical pyrolyzer 20 is heated by the vertical pyrolyzer control unit 16, with the heating rate set to 5℃ / min, the pyrolysis temperature to 650℃, and the pyrolysis time to 2h.

[0108] S3. Sludge Cyclone Pyrolysis: After the activated sludge particles enter the cyclone pyrolysis chamber 21 tangentially, the nitrogen gas intake is controlled to be 1 m³ / s. 3 / h, so that the activated sludge particles remain suspended in the cyclone pyrolysis chamber 21 while realizing the particle's self-rotation-suspension recirculation coupled pyrolysis.

[0109] S4. Cyclone Separation and Collection of Pyrolysis Products: After pyrolysis, the nitrogen flow rate is gradually adjusted to 0, allowing the solid product (sludge activated carbon) to flow into the bottom storage hopper 50 through the underflow pipe 23. The pyrolysis gas and pyrolysis tar are discharged from the overflow pipe 22 at the top of the cyclone pyrolyzer 20 and enter the oil-gas separator 40, where they are further separated to obtain pure pyrolysis tar and pyrolysis gas. The specific surface area and pore size of the obtained sludge activated carbon are analyzed, and the data are shown in Table 4.

[0110] (3) Preparation of activated carbon by conventional pyrolysis method

[0111] Comparative Example 1

[0112] The activated sludge particles were pyrolyzed using a conventional pyrolysis method. The specific surface area and pore size of the resulting activated carbon were analyzed, and the data are shown in Table 4.

[0113] Table 4. Specific surface area-pore size analysis of sludge activated carbon prepared by different pyrolysis methods and temperatures.

[0114]

[0115] As shown in Table 4, the specific surface area and pore size analysis results of the sludge activated carbon indicate that the cyclone pyrolysis method of this invention significantly improves both the specific surface area and micropore volume compared to the conventional pyrolysis method. Temperature is the most crucial parameter in the pyrolysis preparation of sludge activated carbon, and at a pyrolysis temperature of 600℃, the specific surface area of ​​the sludge activated carbon obtained by conventional tubular furnace pyrolysis is only 105.2207 m². 2 / g, while the specific surface area of ​​the activated carbon from sludge prepared by the cyclone pyrolysis method reached 132.5391m². 2 / g and the micropore volume is 0.006036cm³ 3 / g increased to 0.010080cm 3 / g; It can be seen that the sludge activated carbon prepared by the method of the present invention has a superior adsorption capacity.

[0116] 3. Preparation of hydrogen-rich gas by pyrolysis

[0117] (1) Sample processing

[0118] After passing through a gravity settling tank, municipal sludge is sent to a plate and frame filter press for physical dewatering. Subsequently, the sludge raw material is treated by a dispersion medium mixing-cyclone self-rotation drying technology to form spherical sludge particles. By adjusting the operating parameters during the drying process, sludge particles with a moisture content of 30% are obtained. The dried sludge particles are then sent to a sludge activation tank 23, where a 2 mol / L potassium hydroxide solution is used as the activator for 24 hours of soaking and activation before use.

[0119] (2) Preparation of hydrogen-rich gas by cyclone pyrolysis

[0120] Example 5

[0121] S1. Activated sludge feeding: The activated sludge particles are stored in the feed funnel 32 of the hydrocyclone pyrolysis device; nitrogen gas is introduced at the inlet of the feed pipe 31, and the sludge particles enter the hydrocyclone pyrolyzer 20 through the feed pipe 31 under the action of the carrier gas nitrogen. The cross-sectional area of ​​the feed pipe is 100 mm². 2 The nitrogen intake flow rate is adjusted to 1m³ via the valve on the nitrogen storage tank. 3 / h;

[0122] S2. Heating of the cyclone pyrolyzer: The vertical pyrolyzer 20 is heated by the vertical pyrolyzer control unit 16, with the heating rate set to 10℃ / min, the pyrolysis temperature to 900℃, and the pyrolysis time to 2h.

[0123] S3. Sludge Cyclone Pyrolysis: After the activated sludge particles enter the cyclone pyrolysis chamber 21 tangentially, the nitrogen gas intake is controlled to be 1 m³ / s. 3 / h, so that the activated sludge particles remain suspended in the cyclone pyrolysis chamber 21 while realizing the particle's self-rotation-suspension recirculation coupled pyrolysis.

[0124] S4. Cyclone Separation and Collection of Pyrolysis Products: After pyrolysis, the nitrogen flow rate is gradually adjusted to 0, allowing the solid product (sludge activated carbon) to flow into the bottom storage hopper 50 through the underflow pipe 23. The pyrolysis gas and pyrolysis tar are discharged from the overflow pipe 22 at the top of the cyclone pyrolyzer 20 and enter the oil-gas separator 40, where they are further separated to obtain pure pyrolysis tar and pyrolysis gas. The gas during the cyclone pyrolysis process is collected through a gas collection bag to obtain sludge cyclone pyrolysis gas, which is detected by a gas chromatograph. The hydrogen production data is shown in Table 5. The composition of the obtained pyrolysis gas is shown in Table 7.

[0125] Comparative Example 2

[0126] The activated sludge particles were pyrolyzed in a fixed-bed reactor at 900℃. The gas during the pyrolysis process was collected through a gas collection bag to obtain sludge cyclone pyrolysis gas, which was detected by gas chromatography. The data are shown in Table 5.

[0127] Table 5. Preparation of hydrogen-rich gas by different pyrolysis methods

[0128] sewage sludge Cyclone pyrolysis 900 265.78 sewage sludge Fixed-bed reactor 900 106.624

[0129] Fixed-bed reactors are a common method for sludge pyrolysis. The material is placed stationary in a tubular furnace, resulting in poor heat transfer efficiency between particles during pyrolysis. This leads to uneven heating of the sludge and requires a long pyrolysis time for complete decomposition. In contrast, cyclone pyrolysis technology allows the sludge particles to undergo high-speed suspension and self-rotation along the reactor wall under the influence of a rotating airflow. The heat transfer surface area between the particles and the airflow increases due to particle rotation, accelerating the mass transfer rate during pyrolysis and directly extending the pyrolysis cycle. Simultaneously, the rotation coupled with centrifugal force initially separates pyrolysis gas, tar, and pyrolysis carbon particles, resulting in higher pyrolysis efficiency. As shown in the table, under the same experimental materials and pyrolysis temperature, the hydrogen production per unit sludge unit using a fixed-bed tubular furnace is only 106.624 mL / g; while the hydrogen production per unit sludge unit using the cyclone suspension and rotation pyrolysis technology in this study is as high as 265.78 mL / g, which is 2.49 times that of the fixed-bed reactor.

[0130] Example 6

[0131] Compared with Example 5, the water content of the sample sludge in this embodiment was 20%, while all other aspects were the same. The components of the collected pyrolysis gas were analyzed, and the data are shown in Table 6.

[0132] Example 7

[0133] Compared with Example 5, the water content of the sample sludge in this embodiment was 35%, while all other aspects were the same. The components of the collected pyrolysis gas were analyzed, and the data are shown in Table 6.

[0134] Example 8

[0135] Compared with Example 5, the water content of the sample sludge in this embodiment was 50%, while all other aspects were the same. The components of the collected pyrolysis gas were analyzed, and the data are shown in Table 6.

[0136] Table 6. Pyrolysis gas components obtained from sludge particles with different moisture contents.

[0137] 20 30.16 35.1 0.12 34.62 35 21.15 41.67 0.05 37.13 50 16.16 42.32 0.04 41.38

[0138] Example 9

[0139] Compared with Example 5, the pyrolysis temperature in this embodiment is 700℃, while all other parameters are the same. The components of the collected pyrolysis gas were analyzed, and the data are shown in Table 7.

[0140] Example 10

[0141] Compared with Example 5, the pyrolysis temperature in this embodiment is 800℃, while all other parameters are the same. The components of the collected pyrolysis gas were analyzed, and the data are shown in Table 7.

[0142] Table 7. Components of pyrolysis gases obtained under different temperature conditions

[0143] 700 34.42 37.26 0.24 28.07 800 14.46 49.28 0.14 36.12 900 21.15 41.67 0.05 37.13

[0144] As can be seen from Tables 6 and 7, in the preparation of hydrogen-rich gas by cyclone pyrolysis, the higher the water content of the sludge particles, the higher the hydrogen content in the prepared pyrolysis gas; and the higher the pyrolysis temperature, the higher the hydrogen content in the prepared pyrolysis gas.

[0145] The cyclone pyrolysis technology in this invention has unique advantages, which can greatly shorten the pyrolysis time and improve the pyrolysis efficiency of sludge particles, resulting in higher quality activated carbon, which meets the requirements of "reduction, harmlessness and resource utilization" in the field of sludge treatment.

[0146] The embodiments listed above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. That is, all equivalent changes and modifications made in accordance with the scope of the claims of this invention should be considered within the technical scope of this invention.

[0147] All references to this invention are incorporated herein by reference as if each reference were individually incorporated herein by reference. Furthermore, it should be understood that after reading the foregoing teachings of this invention, those skilled in the art can make various alterations or modifications to this invention, and these equivalent forms also fall within the scope defined by the claims of this application.

Claims

1. A sludge cyclone pyrolysis method, characterized in that, Includes the following steps: S1. Activated sludge feeding: The activated sludge particles are carried into the cyclone pyrolyzer along the tangential direction of the cyclone pyrolyzer by a nitrogen gas flow; S2. Heating of the cyclone pyrolyzer: The cyclone pyrolyzer is heated by a heating device so that the temperature inside the cyclone pyrolyzer is 600℃~1000℃; S3. Sludge cyclone pyrolysis: After the activated sludge particles enter the cyclone pyrolyzer tangentially, the nitrogen gas inlet speed is adjusted so that the activated sludge particles remain in suspension in the cyclone pyrolyzer while realizing the particle self-rotation-suspension recirculation coupled pyrolysis. S4. Cyclone separation and collection of pyrolysis products: After pyrolysis is completed, the nitrogen gas inlet speed is gradually adjusted to 0, so that the solid products of sludge pyrolysis flow to the bottom of the cyclone pyrolyzer for collection, and the pyrolysis gas and pyrolysis tar are discharged from the top of the cyclone pyrolyzer for collection. In step S1, sludge activation uses a 1.5 mol / L to 2 mol / L potassium hydroxide solution as the activating agent, and the sludge is activated by immersion for 20 to 30 hours; the sludge particle size is 1 to 5 mm; and the nitrogen gas intake rate in steps S1 and S2 is 0.6 m³ / h. 3 / h~1.2m 3 / h, air inlet cross-sectional area is 100mm² 2 ~500mm 2 In step S2, the heating rate of the cyclone pyrolyzer is controlled at 5℃ / min to 10℃ / min; in step S3, the cyclone pyrolysis time is 1.5 to 2 hours.

2. A sludge cyclone pyrolysis device, characterized in that, include A pyrolysis furnace includes a furnace shell and a heating chamber formed within the furnace shell. The upper side wall of the furnace shell is provided with a pyrolysis furnace inlet, the top of the furnace shell is provided with a pyrolysis furnace top outlet, and the bottom of the furnace shell is provided with a pyrolysis furnace bottom outlet. The pyrolysis furnace is also equipped with a pyrolysis furnace control unit for controlling the pyrolysis process. A cyclone pyrolyzer has a cyclone pyrolysis chamber located within the heating chamber of a pyrolysis furnace. The cyclone pyrolysis chamber has an overflow pipe at its top and an underflow pipe at its bottom, with a tangential inlet located on its side wall near the top. The underflow pipe extends from the bottom outlet of the pyrolysis furnace, the overflow pipe extends from the top outlet of the pyrolysis furnace, and the tangential inlet extends from the inlet of the pyrolysis furnace. The feeding assembly includes a feed pipe and a feed funnel whose bottom is connected to the top wall of the feed pipe; wherein, the feed pipe is sealed to a tangential inlet for the introduction of nitrogen gas flow into the cyclone pyrolyzer and for the feeding of activated sludge, and the feed funnel is used to store activated sludge particles. An oil-gas separator is sealed to the outlet end of the overflow pipe via a pipeline and is used to receive and separate tar and pyrolysis gas generated by pyrolysis. A storage hopper is located at the lower end of the underflow pipe and is sealed to the underflow pipe for collecting solid products generated by pyrolysis.

3. The sludge cyclone pyrolysis device according to claim 2, characterized in that, The cyclone pyrolyzer is made of quartz.

4. The sludge cyclone pyrolysis device according to claim 2, characterized in that, The upper half of the cyclone pyrolysis chamber is a columnar structure, and the lower half is a tapered cone structure.

5. The sludge cyclone pyrolysis device according to claim 2, characterized in that, The pyrolysis furnace is a vertical pyrolysis furnace, and the shape of its heating chamber matches the outer surface of the cyclone pyrolyzer.

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