Multi-source waste heat coordinated staged sludge dryer and treatment method thereof
By using a multi-source waste heat co-processing staged sludge dryer, which combines pretreatment, multi-source waste heat drying, and closed-loop purification circulation, the problems of high energy consumption, poor uniformity, and high environmental risks of existing sludge dryers are solved. It achieves high efficiency and energy saving, uniform drying, and zero waste gas emissions, and is suitable for various types of sludge.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGMEN KAIXIN AUTOMATION EQUIP CO LTD
- Filing Date
- 2026-03-13
- Publication Date
- 2026-05-29
AI Technical Summary
Existing sludge dryers have high energy consumption, poor drying uniformity, and significant environmental risks. They also have low waste heat utilization rates. Existing low-temperature waste heat equipment suffers from poor waste heat adaptability and insufficient synergy between drying and crushing.
The multi-source waste heat synergistic staged sludge dryer includes a pretreatment module, a multi-source waste heat drying module, a closed-loop purification and circulation module, and an intelligent control system. Through the combination of spiral extrusion, magnetic impurity removal, preheated conveyor belt, and multi-stage drying zones, it achieves efficient recovery of multi-source waste heat and uniform drying of sludge, and reduces pollutant emissions through closed-loop circulation and multi-stage purification.
It achieves extreme energy saving, reducing energy consumption per unit of water evaporation by more than 50%, with a sludge moisture content error of ≤5%, and is environmentally friendly and safe with no waste gas emissions. It is compatible with various sludge types, and its modular design facilitates installation and maintenance.
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Figure CN122102471A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of sludge treatment technology, and in particular to a multi-source waste heat synergistic staged sludge dryer and its treatment method. Background Technology
[0002] A sludge dryer is a drying device used to process materials such as urban sludge and industrial sludge. It reduces the moisture content from 90% to 10% to 30% by evaporating moisture with heat, making it easier to dispose of for incineration, agricultural use or landfill.
[0003] Existing sludge dryers suffer from three major drawbacks: First, high energy consumption—direct heating equipment requires 800-850 kcal of energy to evaporate each liter of water, and the waste heat utilization rate is less than 30%; second, poor drying uniformity—the moisture content difference between the inside and outside of the accumulated sludge can exceed 20%, easily leading to caking and clumping, requiring additional energy for subsequent crushing; third, significant environmental risks—odorous gases such as H2S and NH3 generated during high-temperature drying are prone to leakage, and exhaust gas treatment costs account for more than 25% of the equipment's operating costs. Although low-temperature waste heat equipment has attempted to solve these problems, it suffers from limitations such as poor waste heat adaptability and insufficient synergy between drying and crushing. Summary of the Invention
[0004] The purpose of this invention is to provide a multi-source waste heat synergy-based graded sludge dryer and its treatment method, which realizes efficient recovery of multi-source waste heat, improves drying uniformity, and effectively reduces pollutant emissions.
[0005] To achieve the above objectives, the present invention provides a graded sludge dryer based on multi-source waste heat synergy, comprising a pretreatment module, a multi-source waste heat drying module, a closed-loop purification circulation module, and an intelligent control system. The output end of the pretreatment module is connected to the input end of the multi-source waste heat drying module. The discharge end of the multi-source waste heat drying module is equipped with a finished product collection unit. The closed-loop purification circulation module and the multi-source waste heat drying module form a gas circulation loop. The intelligent control system is electrically connected to each module.
[0006] Preferably, the pretreatment module is located on the outside of the dryer body and is fixedly connected to the dryer body via a bracket. The pretreatment module includes a spiral extrusion mechanism, a magnetic impurity removal roller, and a preheating conveyor belt connected in sequence. The spiral extrusion mechanism includes a feeding hopper, the feeding port of which is flexibly connected to the barrel. An extrusion screw is provided at the bottom of the barrel. One side of the extrusion screw is connected to a drive unit, and the other side of the extrusion screw corresponds to the discharge port of the barrel. The outside of the discharge port is connected to a forming die head via a barrel flange.
[0007] Preferably, the inner wall of the feed hopper is provided with a polytetrafluoroethylene anti-stick coating, and the bottom of the feed hopper is provided with a frequency converter to avoid bridging and clogging by wet sludge. At the same time, the feed inlet of the feed hopper is provided with a flexible connection to the barrel to ensure the connection stability between the feed hopper and the barrel during vibration.
[0008] Furthermore, the driving unit is a variable frequency motor + gearbox, and the die head end face of the forming die head has a number of extrusion holes evenly distributed. The diameter of the extrusion holes is 8-12mm, the channel length is 50mm, and the hole wall roughness Ra≤0.8μm. The outer side of the forming die head is provided with a detachable cleaning ring to facilitate unblocking the blocked channels.
[0009] Furthermore, the magnetic impurity removal roller is located at the bottom of the extrusion orifice. The roller body of the magnetic impurity removal roller is made of hollow stainless steel, and annular neodymium iron boron magnets are evenly embedded inside along the roller body axis. Both ends of the roller body are connected to the bracket through deep groove ball bearings. One end of the roller body is linked to the variable frequency motor of the screw extruder through a synchronous belt to ensure that the roller body speed matches the screw speed and achieve synchronous impurity removal.
[0010] Furthermore, the input end of the preheating conveyor belt is aligned with the output end of the magnetic impurity removal roller, and the output end of the preheating conveyor belt extends to the feed inlet of the primary drying zone of the multi-source waste heat drying module. The preheating conveyor belt is made of high-temperature resistant polyester canvas, with anti-slip protrusions on the surface and a 15mm high guard edge.
[0011] Furthermore, an S-shaped stainless steel heating tube is embedded inside the preheated conveyor belt. The S-shaped stainless steel heating tube is connected to the waste heat recovery pipeline of the multi-source waste heat drying module. The waste heat flow rate is adjusted by a valve to stabilize the surface temperature of the preheated conveyor belt at 50~60℃.
[0012] Furthermore, the preheated conveyor belt is equipped with a drive roller and a driven roller at both ends. The drive roller is driven by a 2.2kW variable frequency motor (speed 5-10r / min, conveyor belt linear speed adjustable 0.08-0.15m / s). The roller surfaces of the drive roller and the driven roller are equipped with a rubber coating layer to increase friction. The driven roller end is equipped with a spiral tensioning mechanism (adjustable stroke 50mm). The tension of the conveyor belt (tension force 20-30kN) is controlled by adjusting bolts to prevent the preheated conveyor belt from slipping during operation.
[0013] Furthermore, the spiral extruder extrudes wet sludge with a moisture content of 70%-80% into strip-shaped structures with a diameter of 8-12mm; the magnetic impurity removal roller has a metal impurity removal rate of ≥95%; the preheating conveyor belt uses the 50-60℃ waste heat from the multi-source waste heat drying module to preheat the sludge, initially evaporating 10% of the surface moisture.
[0014] Preferably, the multi-source waste heat drying module includes a waste heat collection unit, a staged drying unit, and a waste heat recovery structure; the waste heat collection unit consists of a flue gas heat exchanger, a condensate heat exchanger, a heat pump evaporator, and a plate heat exchanger, and the plate heat exchanger integrates the multi-source waste heat into dry hot air at 60-70℃; the staged drying unit includes a primary drying zone and a secondary drying zone.
[0015] Preferably, the primary drying zone is a ring-shaped, evenly distributed hot air jet pipe with a wind speed of 1.2-1.5 m / s, and the secondary drying zone is a closed-loop air duct with a duct temperature of 65-70℃ and humidity ≤20%; the waste heat recovery structure recovers the heat of the humid air at the outlet of the secondary drying zone through a heat pump condenser, with a heat recovery efficiency ≥65%.
[0016] Furthermore, the flue gas heat exchanger is adapted to waste incinerator exhaust gas at 120-180℃, the condensate heat exchanger is adapted to steam condensate at 90-110℃, and the heat pump evaporator is adapted to ambient heat energy; the primary drying zone reduces the sludge moisture content to 50%-55%, and the secondary drying zone reduces the sludge moisture content to an adjustable 15%-20%.
[0017] Preferably, the closed-loop purification and circulation module includes a condensation and dehydration unit, a multi-stage purification unit, and a gas circulation unit; the condensation and dehydration unit cools the humid air to 15-20℃ through a water-cooled pre-cooling coil, with a condensate recovery rate of ≥95%; the multi-stage purification unit is sequentially equipped with an activated carbon adsorption tower, a two-stage water mist spray tower, and a UV photolysis device; the gas circulation unit heats the purified air through a heat pump condenser and then returns it to the multi-source waste heat drying module.
[0018] Furthermore, the particulate matter content in the gas treated by the multi-stage purification unit is ≤10 mg / m³. 3 Odor concentration ≤200 dimensionless, in compliance with the "Odor Pollutant Emission Standard" (GB14554-93); condensate discharge in compliance with the "Integrated Wastewater Discharge Standard" (GB8978-1996).
[0019] Preferably, the intelligent control system adopts PLC + touch screen control to monitor the temperature and humidity of the primary / secondary drying zone, sludge moisture content, and waste heat supply intensity parameters in real time; the intelligent control system is equipped with a thermal induction drive mechanism, which is based on shape memory alloy spring sheet and automatically adjusts the rotation speed of the crushing roller according to the hot air temperature. For every 5°C increase in temperature, the rotation speed increases by 0.2 r / min.
[0020] Furthermore, the intelligent control system supports remote setting of sludge moisture content from 10% to 40%, has an automatic alarm function for equipment faults, and has a maintenance response time of ≤5 minutes.
[0021] This invention also provides a treatment method for sludge using a multi-source waste heat synergy staged sludge dryer, comprising the following steps: S1. Wet sludge is formed by a spiral extruder → impurities are removed by a magnetic impurity removal roller → preheating is achieved by a preheating conveyor belt; S2. After pretreatment, the sludge enters the primary drying zone and is dried to a moisture content of 50%-55% by multi-source waste heat hot air jet. S3. Enter the secondary drying zone and dry to the target moisture content in a closed-loop hot air environment; S4. The dried sludge falls directly into the finished product collection unit for collection. S5. The humid air generated during drying undergoes condensation and dehydration, multi-stage purification, and waste heat recovery in sequence. The purified air is then returned to the drying module for recycling.
[0022] Therefore, the present invention employs the above-mentioned multi-source waste heat synergistic staged sludge dryer and its treatment method, and the technical effects are as follows: Extreme energy saving: Multi-source waste heat recovery + closed circulation reduces the energy consumption per unit of water evaporation to 380-420 kcal, saving more than 50% energy compared to traditional equipment. It can save more than 3 million yuan in costs when treating 10,000 tons of sludge per year. Uniform drying: graded drying, sludge moisture content error ≤5%, caking rate close to 0, subsequent resource utilization rate increased by 20%; Environmental protection and safety: Closed-loop circulation + multi-stage purification achieves zero emissions of exhaust gas, low-temperature operation (≤70℃) poses no explosion hazard, and no nitrogen flushing protection is required; High versatility: It is suitable for domestic sewage sludge as well as industrial sludge from printing and dyeing, chemical industry, copper-containing hazardous waste, etc. It has a wide range of adjustable moisture content (10%-40%) and modular design for easy installation and maintenance.
[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0024] Figure 1 This is a schematic diagram of the structure of a multi-source waste heat synergistic graded sludge dryer according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the pretreatment module structure of an embodiment of a multi-source waste heat synergistic graded sludge dryer of the present invention; Figure 3 This is a cross-sectional view of the preheating conveyor belt of an embodiment of a multi-source waste heat synergistic graded sludge dryer according to the present invention; Figure 4 This is a schematic diagram of the multi-source waste heat drying module structure of an embodiment of a multi-source waste heat synergistic graded sludge dryer according to the present invention; Figure 5This is a cross-sectional view of the staged drying unit in an embodiment of a staged sludge dryer with multi-source waste heat synergy according to the present invention. Figure 6 This is a flowchart of a multi-source waste heat synergistic graded sludge dryer processing method according to the present invention.
[0025] Figure Labels 1. Feed hopper; 2. Support frame; 3. Machine barrel; 4. Forming die head; 5. Magnetic impurity removal roller; 6. Preheating conveyor belt; 7. Multi-source waste heat drying module; 8. Closed-loop purification circulation module; 9. Touch screen; 10. S-shaped stainless steel heating tube; 11. Side guard; 12. Graded drying unit; 13. Condensate heat exchanger; 14. Flue gas heat exchanger; 15. Heat pump evaporator; 16. Plate heat exchanger; 17. Primary drying zone; 18. Secondary drying zone. Detailed Implementation
[0026] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.
[0027] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0028] Example 1 This embodiment takes the daily processing of 10 tons of dyeing and printing sludge as the application scenario. The initial moisture content of the sludge is 75%, and the target moisture content is 20%. It is suitable for dual waste heat sources: exhaust gas (150°C) and steam condensate (100°C) from a waste incinerator. The specific implementation method of the present invention is described in detail.
[0029] I. Overall Equipment Configuration: This embodiment of the multi-source waste heat synergistic graded sludge dryer has overall dimensions of 8.5m (length) × 2.2m (width) × 3.0m (height). The frame is welded from Q235 steel, with a surface coated with anti-rust primer and industrial topcoat. The total weight of the equipment is 5.8 tons. The sludge dryer includes a pretreatment module, a multi-source waste heat drying module 7, a closed-loop purification circulation module 8, and an intelligent control system. The output end of the pretreatment module is connected to the input end of the multi-source waste heat drying module 7. The discharge end of the multi-source waste heat drying module 7 is equipped with a finished product collection unit. The closed-loop purification circulation module 8 and the multi-source waste heat drying module 7 form a gas circulation loop. The intelligent control system is electrically connected to each module. Each module is configured according to the attached... Figure 1 The layout shown is an assembly.
[0030] II. Specific structure and parameters of each module: (a) The spiral extrusion mechanism in the pretreatment module (e.g.) Figure 2 , Figure 3 (as shown) Feed hopper 1 has a volume of 0.5m³. 3 The inner wall has a 1mm thick polytetrafluoroethylene anti-stick coating. The bottom variable frequency vibrator is model ZDS-10 with a vibration frequency of 25Hz. The feed port and the barrel 3 are connected by a silicone rubber flexible connection (inner diameter 180mm, length 200mm) to meet the vibration compensation of ±10mm.
[0031] The barrel 3 is 1200mm long and 180mm in diameter. The double-layer jacket is 15mm thick and is insulated with 35℃ warm water. The jacket inlet is connected to the hot water pipe network in the workshop, and the outlet is connected to the return water pipe.
[0032] The extrusion screw is made of 40Cr material, with a pitch of 120mm and a gradual compression ratio of 1:1.2 (feed section) to 1:1.8 (extrusion section). The drive unit is a 5.5kW variable frequency motor (model YVP200L1-6) + gearbox (reduction ratio 1:50), and the screw speed is adjusted to 20r / min.
[0033] The forming die head 4 is connected to the barrel flange by 8 sets of M16×45 bolts. There are 24 extrusion holes evenly distributed on the end face of the die head, with a hole diameter of 10mm, a channel length of 50mm, and a hole wall roughness of Ra=0.6μm. The outer detachable cleaning ring is made of 304 stainless steel with a thickness of 15mm.
[0034] The magnetic impurity removal roller 5 is installed 150mm directly below the forming die head 4 and is fixed by the bracket 2. The height of the bracket 2 can be adjusted within ±20mm. The roller body is a hollow stainless steel roller (outer diameter 120mm, length 600mm, wall thickness 8mm). It is internally embedded with 3 sets of annular neodymium iron boron magnets (8 pieces per set, single piece size 50mm×30mm×10mm, surface magnetic field strength 12000Gs), with a magnet spacing of 100mm.
[0035] The roller body is equipped with deep groove ball bearings (model 6206) at both ends. It is linked to the variable frequency motor at the extrusion screw via HTD-5M synchronous belt with a transmission ratio of 1:1. The roller body speed is 20r / min. The arc-shaped collection groove below has an arc of 120° and a groove width of 130mm. The built-in magnetic scraper has a 98% fit with the roller body surface.
[0036] Preheated conveyor belt 6 (e.g.) Figure 3 (as shown) The total length is 3000mm, the width is 600mm, the installation tilt angle is 4°, the distance between the input end and the discharge end of the magnetic impurity removal roller 5 is 50mm, and the output end is flexibly connected to the feed port of the primary drying zone 17 through a guide plate (tilt angle 15°).
[0037] The preheated conveyor belt 6 is made of high-temperature resistant polyester canvas (temperature resistance 120℃, thickness 3mm), with diamond-shaped anti-slip protrusions on the surface 2mm high and spaced 20mm apart, and edge guards 11 15mm high; it is internally embedded with S-shaped stainless steel heating tubes 10 (pipe diameter 12mm, wall thickness 2mm, total length 15m), which are connected to the waste heat recovery pipe of the multi-source waste heat drying module 7 through a DN50 valve, and the surface temperature of the conveyor belt is stabilized at 55℃.
[0038] The preheated conveyor belt 6 has a drive roller diameter of 100mm and a driven roller diameter of 80mm. The rubber coating thickness of the drive roller and driven roller surface is 5mm (Shore hardness 65A). The drive roller is driven by a 2.2kW variable frequency motor (model YVP132S-6) with a speed of 8r / min and a conveyor belt linear speed of 0.12m / s. The driven roller end has a spiral tensioning mechanism with an adjustment stroke of 50mm and a tension force of 25kN.
[0039] (ii) Multi-source waste heat drying module 7 (e.g.) Figure 4 , Figure 5 (as shown) Among them, the flue gas heat exchanger 14 in the waste heat collection unit is model BR0.3-1.0-1.6, which is suitable for the exhaust gas of a 150℃ waste incinerator and has a heat exchange area of 30m². 2 The condensate heat exchanger, model 13, is an F-type shell-and-tube heat exchanger, suitable for 100℃ steam condensate, with a heat exchange area of 15m². 2 The heat pump evaporator model 15 is EV-100, with a rated cooling capacity of 10kW, and is compatible with environmental heat recovery.
[0040] The plate heat exchanger model 16 is M10-B, with a heat exchange area of 20m². 2 The waste heat from multiple sources is integrated into dry hot air at 65℃, with a hot air volume of 12,000 m³ / h. 3 / h.
[0041] Graded drying unit 12 (e.g.) Figure 5 (as shown) The primary drying zone 17 is a cylindrical cavity (1.2m in diameter and 2.5m in length), with 48 hot air jet pipes (8mm in diameter and 50mm in spacing) evenly distributed in a ring on the inner wall. The hot air velocity is 1.4m / s, and the sludge stays in this zone for 8 minutes, reducing the moisture content to 52%.
[0042] The secondary drying zone 18 is a closed-loop annular air duct (inner diameter 1000mm, outer diameter 1400mm, circumference 3200mm). The duct temperature is 68℃, the humidity is 18%, the hot air velocity is 0.9m / s, the sludge retention time is 12min, and the moisture content is reduced to 20%.
[0043] Waste heat recovery structure: The heat pump condenser is model CN-100 with a rated heating capacity of 12kW. It recovers heat from the humid air (temperature 55℃, humidity 55%) at the outlet of the secondary drying zone 18 with a heat recovery efficiency of 68%. The recovered heat is used to preheat the cold air entering the plate heat exchanger 16.
[0044] (III) Closed-loop purification circulation module 8: The condensate removal unit features a water-cooled pre-cooling coil made of 304 stainless steel with a diameter of 25mm and a total length of 80m. This coil cools the humid air to 18℃ and achieves a condensate recovery rate of 96%. The condensate is then connected to the workshop wastewater treatment system via a DN32 pipe, and the water quality meets the Class I standard of the "Integrated Wastewater Discharge Standard" (GB8978-1996).
[0045] Multi-stage purification unit: The activated carbon adsorption tower is model XT-1000, filled with granular activated carbon (particle size 3-5mm, packing amount 0.8m³). 3 The secondary water mist spray tower adopts a counter-current structure, the spray liquid is a 5% NaOH aqueous solution, and the spray volume is 5m³. 3 / h; UV photolysis device power 15kW, wavelength 185-254nm.
[0046] The particulate matter content in the purified gas was 7 mg / m³. 3 The odor concentration was 180 (dimensionless), which meets the "Emission Standard for Odor Pollutants" (GB14554-93).
[0047] Gas circulation unit: Centrifugal circulating fan (model 9-19-5A, power 7.5kW, air volume 12000m³) is used. 3 The purified air is heated to 60°C by a heat pump condenser and then returned to the primary drying zone 17 and the secondary drying zone 18.
[0048] (iv) Intelligent Control System: The system uses a PLC controller (model S7-1200) and a touch screen (10.4 inches) to monitor parameters such as the temperature (65℃) of the primary drying zone 17, the temperature (68℃) of the secondary drying zone 18, the humidity (18%), the sludge moisture content (online monitoring instrument model MS-300), and the waste heat supply intensity in real time.
[0049] The thermal induction drive mechanism is based on shape memory alloy springs and automatically adjusts the air velocity of the 17 jet pipes in the primary drying zone according to the hot air temperature. For every 5°C increase in temperature, the air velocity increases by 0.1 m / s. It supports remote setting of sludge moisture content, automatic alarm for equipment failure, and operation and maintenance response time of ≤3 minutes.
[0050] (v) The finished product collection unit is located directly below the discharge end of the secondary drying zone 18, and is a stainless steel collection hopper (0.5m³). 3 The bottom is equipped with a pneumatic discharge valve (150mm diameter, 0.5MPa working pressure) to achieve quantitative discharge. The collected dry sludge particles have a particle size of 2-5mm and a moisture content uniformity error of ≤4%.
[0051] III. The equipment operation process is as follows (e.g.) Figure 6 (as shown) S1. Pretreatment stage: 10 tons of wet sludge with a moisture content of 75% is fed into the feed hopper 1. A frequency converter vibrator prevents sludge bridging. The sludge is extruded into strips with a diameter of 10mm by a screw extruder. A magnetic impurity removal roller 5 rotates synchronously (20r / min) to adsorb metal impurities (removal rate 96%). The strip sludge falls into the preheated conveyor belt 6, where 10% of the surface moisture is initially evaporated under residual heat at 55℃. After pretreatment, the moisture content of the sludge is reduced to 68%.
[0052] S2, Primary Drying Stage: The pretreated sludge enters the primary drying zone 17 through the guide plate. Hot air at 65°C is sprayed through the annular jet pipe at a wind speed of 1.4 m / s to dry the surface of the sludge. After 8 minutes, the moisture content of the sludge drops to 52%.
[0053] S3, Secondary Drying Stage: The sludge enters the closed-loop air duct of the secondary drying zone 18 and is deeply dried for 12 minutes in a hot air environment of 68℃ and 18% humidity, reducing the moisture content to the target value of 20%.
[0054] S4. Finished Product Collection Stage: The dried sludge particles fall directly into the finished product collection unit and are discharged quantitatively through the pneumatic unloading valve, with 2.6 tons of dried sludge collected daily.
[0055] S5. Exhaust Gas Treatment and Recirculation Stage: Moist air generated during drying (flow rate 12000 m³ / h) 3The gas enters the closed-loop purification circulation module 8 ( / h), where it is condensed and dehydrated by a water-cooled pre-cooling coil (recovery rate 96%). It then passes through an activated carbon adsorption tower, a secondary water mist spray tower, and a UV photolysis device for purification. The purified gas recovers heat through a heat pump condenser (heat recovery efficiency 68%), and after being heated to 60°C, it is returned to the graded drying unit 12 for recycling.
[0056] IV. Verification of Implementation Results: This embodiment underwent a 72-hour continuous test, and the results are as follows: Energy saving effect: The energy consumption per unit of water evaporation is 395 kcal, which is 51.8% more energy-efficient than the traditional electric heating sludge dryer (energy consumption 820 kcal). It can save 3.12 million yuan in electricity costs when processing 3,600 tons of sludge per year. Drying uniformity: The moisture content of the dried sludge had an error of 3.2%, with no caking, which improves the utilization rate of subsequent resource recovery (ceramsite production); Environmental indicators: zero exhaust gas emissions, particulate matter 7mg / m³ 3 H2S content 0.3 mg / m³ 3 NH3 content 0.4 mg / m³ 3 All of them are superior to national standards; Operational stability: The equipment operates continuously without faults, all modules are smoothly connected, the air leakage rate is 0.3%, and the operation and maintenance costs are lower than those of traditional equipment.
[0057] Therefore, the present invention employs the above-mentioned multi-source waste heat synergistic graded sludge dryer and its treatment method to achieve efficient recovery of multi-source waste heat, improve drying uniformity and effectively reduce pollutant emissions.
[0058] It is worth noting that all the contents not described in detail in this invention are existing technologies and are well known to those skilled in the art.
[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A multi-source waste heat synergistic staged sludge dryer, characterized in that, It includes a pretreatment module, a multi-source waste heat drying module, a closed-loop purification and circulation module, and an intelligent control system. The output end of the pretreatment module is connected to the input end of the multi-source waste heat drying module. The discharge end of the multi-source waste heat drying module is equipped with a finished product collection unit. The closed-loop purification and circulation module and the multi-source waste heat drying module form a gas circulation loop. The intelligent control system is electrically connected to each module.
2. The staged sludge dryer with multi-source waste heat synergy according to claim 1, characterized in that: The pretreatment module is located on the outside of the dryer body and is fixedly connected to the dryer body by a bracket. The pretreatment module includes a spiral extrusion mechanism, a magnetic impurity removal roller and a preheating conveyor belt connected in sequence. The spiral extrusion mechanism includes a feeding hopper, the feeding port of the feeding hopper is flexibly connected to the barrel, the bottom of the barrel is provided with an extrusion screw, one side of the extrusion screw is connected to a drive unit, the other side of the extrusion screw corresponds to the discharge port of the barrel, and the outside of the discharge port is connected to a forming die head through a barrel flange.
3. A multi-source waste heat synergistic staged sludge dryer according to claim 2, characterized in that: The inner wall of the feed hopper is coated with polytetrafluoroethylene non-stick coating, the bottom of the feed hopper is equipped with a frequency converter vibrator, the drive unit is a frequency converter motor + gearbox, and the die end face of the forming die head is evenly distributed with several extrusion holes, the diameter of the extrusion holes is 8-12mm, the channel length is 50mm, and the hole wall roughness Ra≤0.8μm.
4. A multi-source waste heat synergistic staged sludge dryer according to claim 2, characterized in that: The magnetic impurity removal roller is located at the bottom of the extrusion hole. The roller body of the magnetic impurity removal roller is made of hollow stainless steel, and annular neodymium iron boron magnets are evenly embedded inside along the roller body axis. Both ends of the roller body are connected to the bracket through deep groove ball bearings, and one end of the roller body is linked to the variable frequency motor of the spiral extruder through a synchronous belt.
5. A multi-source waste heat synergistic staged sludge dryer according to claim 2, characterized in that: The input end of the preheating conveyor belt is aligned with the output end of the magnetic impurity removal roller, and the output end of the preheating conveyor belt extends to the feed inlet of the primary drying zone of the multi-source waste heat drying module. The preheating conveyor belt is made of high-temperature resistant polyester canvas with anti-slip protrusions on the surface and 15mm high guard edges. An S-shaped stainless steel heating tube is embedded inside the preheating conveyor belt, and the S-shaped stainless steel heating tube is connected to the waste heat recovery pipeline of the multi-source waste heat drying module. The two ends of the preheating conveyor belt are respectively equipped with a drive roller and a driven roller, and the roller body surfaces of the drive roller and the driven roller are equipped with a rubber coating layer.
6. A multi-source waste heat synergistic staged sludge dryer according to claim 1, characterized in that: The multi-source waste heat drying module includes a waste heat collection unit, a staged drying unit, and a waste heat recovery structure; the waste heat collection unit consists of a flue gas heat exchanger, a condensate heat exchanger, a heat pump evaporator, and a plate heat exchanger; the staged drying unit includes a primary drying zone and a secondary drying zone.
7. A multi-source waste heat synergistic staged sludge dryer according to claim 6, characterized in that: The primary drying zone consists of a ring-shaped, evenly distributed hot air jet pipe with a wind speed of 1.2-1.5 m / s. The secondary drying zone is a closed-loop air duct with a duct temperature of 65-70℃ and humidity ≤20%. The waste heat recovery structure recovers heat from the humid air at the outlet of the secondary drying zone through a heat pump condenser.
8. A multi-source waste heat synergistic staged sludge dryer according to claim 1, characterized in that: The closed-loop purification and circulation module includes a condensation and dehydration unit, a multi-stage purification unit, and a gas circulation unit. The condensation and dehydration unit cools the humid air to 15-20°C using a water-cooled pre-cooling coil. The multi-stage purification unit is equipped with an activated carbon adsorption tower, a two-stage water mist spray tower, and a UV photolysis device. The gas circulation unit heats the purified air through a heat pump condenser and then returns it to the multi-source waste heat drying module.
9. A multi-source waste heat synergistic staged sludge dryer according to claim 1, characterized in that: The intelligent control system adopts PLC + touch screen control to monitor the temperature and humidity of the primary / secondary drying zone, sludge moisture content, and waste heat supply intensity parameters in real time. The intelligent control system is equipped with a thermal induction drive mechanism, which is based on shape memory alloy springs and automatically adjusts the rotation speed of the crushing roller according to the hot air temperature. For every 5°C increase in temperature, the rotation speed increases by 0.2 r / min.
10. A processing method using the dryer according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Wet sludge is formed by a spiral extruder → impurities are removed by a magnetic impurity removal roller → preheating is achieved by a preheating conveyor belt; S2. After pretreatment, the sludge enters the primary drying zone and is dried to a moisture content of 50%-55% by multi-source waste heat hot air jet. S3. Enter the secondary drying zone and dry to the target moisture content in a closed-loop hot air environment; S4. The dried sludge falls directly into the finished product collection unit for collection. S5. The humid air generated during drying undergoes condensation and dehydration, multi-stage purification, and waste heat recovery in sequence. The purified air is then returned to the drying module for recycling.