A sludge efficient dewatering conditioning method based on multi-pulse shock wave

Abstract

The application discloses a sludge efficient dewatering conditioning method based on multi-pulse shock waves and relates to the technical field of sewage treatment, which comprises sludge pretreatment, multi-pulse detonation shock and energy recovery dewatering; wherein the step pressure in the multi-pulse detonation shock is 0.5-4.0 MPa, and the pulse frequency is 1-10 Hz. A porous impact plate is arranged in a spherical detonation bin, a pulse electromagnetic valve is arranged on a pipeline through which a high-pressure gas storage tank leads to the spherical detonation bin, and a porous impact plate is arranged at the outlet end of the pipeline; the energy recovery system comprises a residual pressure converter and a heat recovery pipe, wherein the residual pressure converter pressurizes the sludge cake, and the heat recovery pipe is used for heating the sludge inlet; and an intelligent control system regulates the pulse frequency and the pressure gradient through PLC. The application adopts the controllable frequency 1-10 Hz pulse detonation shock wave, which gradually collapses the sludge extracellular polymeric substance EPS network structure through the pressure accumulation effect, thereby avoiding the waste of single impact energy.

Description

Technical Field

[0001] This invention relates to the field of sludge treatment technology, specifically to a device and method for destroying the microstructure of sludge and improving its dewatering performance through multi-frequency pulsed detonation shock waves, which is particularly suitable for the pretreatment of municipal sludge with high water content and oily sludge. Background Technology

[0002] Existing technological shortcomings: (1) Physical methods are inefficient and energy-intensive. Ultrasonic conditioning technology relies on cavitation effects, but its energy consumption reaches 1.2 kWh / m³ when treating sludge with a moisture content of 98%. 3 The capillary suction time (CST) is reduced by only 30% (data source: Journal of Environmental Engineering, 2020); the power consumption of traditional high-pressure filter presses is 5-8 kWh / ton of sludge, and the moisture content of the sludge cake is still higher than 65% (Technical Specification for Sludge Treatment in Urban Wastewater Treatment Plants CJJ131-2017).

[0003] (2) Chemical methods are costly and pollute the environment. The Fenton oxidation method requires the addition of Fe2+ (0.1 mol / L) and H2O2 (0.3 mol / L), with a treatment cost of more than 2 yuan / ton and a sludge calorific value loss of more than 25%.

[0004] (3) The complex steam explosion technology of thermal equipment (CN201410263484A) requires maintaining a high temperature of above 120℃, the equipment corrosion rate is >3mm / year, and the heat loss reaches 15%.

[0005] The technology gap in detonation conditioning: The instantaneous ultra-high pressure (microsecond-level pressure peak) generated by detonation can efficiently destroy sludge flocs and cell walls, but existing research is mostly used for soil remediation or ore crushing, and its application in the field of sludge dewatering has not been seen. In particular, the problem of multi-scale structural damage in sludge dewatering has not been solved, and there is a lack of energy recycling design. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a highly efficient sludge dewatering and conditioning device and method based on multi-pulse detonation shock waves. The method of this invention uses pulsed detonation shock waves with a controllable frequency of 1-10Hz to gradually disintegrate the extracellular polymeric EPS network structure of sludge through the pressure accumulation effect, thus avoiding the waste of energy from a single impact.

[0007] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0008] A method for efficient sludge dewatering and conditioning based on multi-pulse detonation shock waves includes sludge pretreatment, multi-pulse detonation shock, and energy recovery dewatering; wherein the multi-pulse detonation shock involves a stepped pressure of 0.5-4.0 MPa and a pulse frequency of 1-10 Hz.

[0009] In the above scheme, the multi-pulse detonation impact includes three stages: the first stage is 0.5MPa impact × (3 to 6) times, with an interval of 2s, to destroy the outer EPS layer; the second stage is 2.0MPa impact × (3 to 5) times, with an interval of 5s, to break microbial cells; the third stage is 3.5 to 4MPa impact × 1 time, to release bound water.

[0010] In the above scheme, energy recovery dewatering: the residual pressure drives the filter press at a pressure of 0-12MPa to obtain a sludge cake with a moisture content of ≤55%, and the residual heat preheats the sludge to 40-50℃.

[0011] In the above scheme, sludge pretreatment involves pumping sludge with a moisture content of 95% to 99% into a spherical detonation chamber, allowing it to stand for 5-20 minutes, draining the supernatant, and then refilling the chamber.

[0012] The apparatus for efficient sludge dewatering and conditioning based on multi-pulse detonation shock waves includes a pulse-type detonation main reaction chamber, an energy recovery system, and an intelligent control system. The pulse-type detonation main reaction chamber comprises a high-pressure gas storage tank, a pulse solenoid valve, and a porous impact plate. The porous impact plate is disposed within a spherical detonation chamber. The pulse solenoid valve is disposed on a pipe connecting the high-pressure gas storage tank to the spherical detonation chamber, with the porous impact plate disposed at the pipe outlet. The energy recovery system includes a pressure converter and a heat recovery pipe. The pressure converter pressurizes the sludge cake, and the heat recovery pipe heats the incoming sludge. The intelligent control system regulates the pulse frequency and pressure gradient via a PLC.

[0013] In the above scheme, the energy recovery system is connected to the spherical detonation chamber through a pipeline. A heat recovery pipe is installed on one side of the pipeline, and a residual pressure converter and a residual pressure driven filter press are installed in sequence at the pipeline output end. The heat recovery pipe is a 316L stainless steel spiral pipe with a heat transfer coefficient ≥120W / (m2·K).

[0014] In the above scheme, the porous impact plate is evenly distributed with conical micropores, and the inlet diameter D1 and outlet diameter D2 of the conical micropores satisfy D1 / D2=3-5.

[0015] In the above scheme, the high-pressure gas storage tank is equipped with a vortex cooling device to maintain the gas temperature from -10°C to 5°C.

[0016] In the above scheme, the outermost part of the spherical detonation chamber is the detonation cavity wall, and an outer wall of the device is provided outside the detonation cavity wall. The space between the detonation cavity wall and the outer wall of the device is filled with shock-absorbing and sound-absorbing filling material; the outer wall of the device is provided with a shock-absorbing bracket, and a lifting ring is provided on the outer wall of the device.

[0017] In the above scheme, the spherical detonation chamber is also connected to a sludge inlet pipe and a sludge discharge pipe. The sludge inlet pipe is equipped with a sludge inlet control valve and a flexible damping valve, and the sludge discharge pipe is equipped with a sludge discharge valve and a flexible damping valve. The liquid level and pressure inside the spherical detonation chamber are monitored by a liquid level sensor and a pressure sensor.

[0018] Beneficial effects:

[0019] Breakthrough in dewatering performance: After treatment by this device, the moisture content of the dewatered sludge cake is reduced from 98% to 50-55%, which is 10-15% lower than that of the traditional ultrasonic treatment method. Energy consumption advantages: The energy recovery system reduces total energy consumption by 30%, and the unit processing cost is less than 0.5 yuan / ton; Zero chemical addition: Purely physical action, no chemical additives, sludge calorific value retention rate >95%, which is beneficial for subsequent incineration disposal.

[0020] The device of this invention has a compact structure, is easy to hoist and move, and improves the comfort of use by incorporating shock-absorbing and sound-absorbing filling materials.

[0021] The method of the present invention further reduces the moisture content of the sludge cake by setting an energy recovery dehydration step and preheats the wastewater entering the sludge, thereby improving the energy utilization rate.

[0022] The device of this invention is equipped with a porous impact plate. The porous plate mainly releases the gas in the high-pressure gas storage tank into the detonation chamber in a uniform and very short time to form a detonation reaction. The holes on the porous plate mainly serve to distribute the gas evenly. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a high-efficiency sludge dewatering and conditioning device based on multi-pulse detonation shock waves. Figure 2 This is a schematic diagram of the porous impact plate involved in the embodiment.

[0024] Figure label: 1-Spherical detonation chamber; 2-Detonation chamber wall; 3-Porous impact plate; 4-Shock-absorbing and sound-absorbing filling material; 5-Shock-absorbing bracket; 6-Foundation and support; 7-Outer wall of the device; 8-Lifting ring; 9-Heat recovery pipe; 10-Residual pressure converter; 11-Residual pressure driven filter press; 12-Pressure sensor; 13-Liquid level sensor; 14-First flexible damping valve; 15-Sludge inlet control valve; 16-Sludge inlet pipe; 17-Exhaust valve; 18-Pressure reducing chamber; 19-Pressure reducing valve; 20-Pulse solenoid valve; 21-High-pressure gas storage tank; 22-Sludge discharge pipe; 23-Sludge discharge valve; 24-Second flexible damping valve. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0026] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0027] A highly efficient sludge dewatering and conditioning method based on multi-pulse detonation shock waves includes sludge pretreatment, multi-pulse detonation shock, and energy recovery dewatering. The multi-pulse detonation shock involves a stepped pressure of 0.5-4.0 MPa and a pulse frequency of 1-10 Hz. The multi-pulse detonation shock consists of three stages: Stage 1: 0.5 MPa shock × (3-6) times, with a 2-s interval, to disrupt the outer EPS layer; Stage 2: 2.0 MPa shock × (3-5) times, with a 5-s interval, to break down microbial cells; Stage 3: 3.5-4 MPa shock × 1 time, to release bound water.

[0028] Energy recovery dewatering: The residual pressure drives the filter press 11 at a pressure of 0-12MPa to obtain a sludge cake with a moisture content of ≤55%, and the residual heat preheats the sludge to 40-50℃.

[0029] Sludge pretreatment: Sludge with a moisture content of 95%-99% is pumped into the spherical detonation chamber 1, allowed to stand for 5-20 minutes, the supernatant is discharged, and then the chamber is refilled. The multi-pulse detonation shock wave sludge high-efficiency dewatering and conditioning device includes a pulse-type detonation main reaction chamber, an energy recovery module, and an intelligent control system. The pulse detonation main reaction chamber includes a high-pressure gas storage tank 21, a pulse solenoid valve 20, and a porous impact plate 3. The porous impact plate 3 is installed inside the spherical detonation chamber 1. The pulse solenoid valve 20 is installed on the pipeline from the high-pressure gas storage tank 21 to the spherical detonation chamber 1, and the porous impact plate 3 is installed at the outlet end of the pipeline. The energy recovery system includes a pressure converter 10 and a heat recovery pipe 9, wherein the pressure converter 10 pressurizes the sludge cake and the heat recovery pipe 9 is used for heating the sludge entering the system. The intelligent control system regulates the pulse frequency and pressure gradient via a PLC; the energy recovery system is connected to the spherical detonation chamber 1 via a pipeline. A heat recovery pipe 9 is installed on one side of the pipeline, and a residual pressure converter 10 and a residual pressure-driven filter press 11 are sequentially installed at the pipeline output end. The heat recovery pipe 9 is a 316L stainless steel spiral tube with a heat transfer coefficient ≥120W / (m²). 2 ·K).

[0030] The inlet diameter D1 and outlet diameter D2 of the conical micropore satisfy D1 / D2=3-5.

[0031] The high-pressure gas storage tank 21 is equipped with a vortex cooling device to maintain the gas temperature from -10°C to 5°C.

[0032] The outermost part of the spherical detonation chamber 1 is the detonation chamber wall 2, and the outer wall 7 of the device is provided outside the detonation chamber wall 2. The space between the detonation chamber wall 2 and the outer wall 7 of the device is filled with shock-absorbing and sound-absorbing filling material 4. The outer wall 7 of the device is provided on the shock-absorbing bracket 5, and a lifting ring 8 is provided on the outer wall 7 of the device.

[0033] The spherical detonation chamber 1 is also connected to a sludge inlet pipe 16 and a sludge discharge pipe 22. The sludge inlet pipe 16 is equipped with a sludge inlet control valve 15 and a first flexible damping valve 14, and the sludge discharge pipe 22 is equipped with a sludge discharge valve 23 and a second flexible damping valve 24. The liquid level and pressure inside the spherical detonation chamber are monitored by a liquid level sensor 13 and a pressure sensor 12.

[0034] 1. Treatment methods (1) Multi-pulse detonation shock control: Pulse detonation shock waves with a controllable frequency of 1-10Hz are used to gradually disintegrate the extracellular polymeric substances (EPS) network structure of sludge through the pressure accumulation effect, avoiding energy waste in a single impact; a stepped pressure gradient is set, 0.5→2.0→3.5MPa, to match the sludge compression characteristics and improve energy utilization.

[0035] (2) Energy recovery and safety design: Integrated residual pressure recovery system: The residual pressure after detonation drives the mechanical dewatering module, such as the diaphragm filter press, to achieve the "impact-pressure filtration" energy closed loop; Explosion-proof chamber design: The split pressure-resistant chamber is adopted, including the main chamber and the buffer chamber. The pressure sensor 12 is linked to the pressure reducing valve 19 to ensure safe operation.

[0036] (3) Multi-field coupling enhancement mechanism: The pressure field, i.e., the detonation shock wave, works in synergy with the temperature field: The local high temperature generated by the shock wave, 60-80℃ instantaneously, promotes water evaporation and reduces sludge viscosity.

[0037] 2. Device Structural Design (1) Detonation main reaction chamber Materials: Inner layer is S31603 biaxial stainless steel with a yield strength ≥550MPa; outer layer has annular reinforcing ribs with a spacing of 50mm × height of 20mm; Core components: High-pressure gas storage tank 21, CO2 / N2, pressure 5MPa, with an internal eddy current cooling device to maintain gas temperature from -10℃ to 5℃; Pulse solenoid valve 20, response time ≤5ms, controlled by a piezoelectric ceramic actuator; Porous impact plate 3: Conical micropores, inlet 0.5mm / outlet 0.1mm, pore density 200 pores / cm2, laser micromachining. The porous impact plate has a ring-shaped structure, in which the central hole is connected to the high-pressure gas pipeline, and the surrounding holes are high-pressure gas release ports.

[0038] (2) Energy recovery system Pressure converter 10: Hydraulic cylinder and accumulator linked, output pressure 0-12MPa; Heat recovery pipe 9: 316L stainless steel spiral pipe, total heat transfer coefficient 120W / (m2·K).

[0039] (3) Intelligent control system The PLC has a preset three-stage program: low-pressure pre-disruption → medium-pressure cell disruption → high-pressure water release, with real-time adjustment of pulse frequency and pressure gradient.

[0040] Operating steps: Sludge pretreatment: Pump sludge with a moisture content of 95%-99% into spherical detonation chamber 1, let it stand for 5-20 minutes, drain the supernatant, and then refill it; Multi-pulse shock: Phase 1: 0.5MPa impact × 5 times, with a 2s interval, to damage the outer EPS layer; Second stage: 2.0MPa shock × 3 times, 5s interval, to break microbial cells; Third stage: 3.5MPa impact × 1 time to release bound water; Energy recovery dewatering: The filter press 11 is driven by residual pressure at a pressure of 0-12 MPa to obtain a sludge cake with a moisture content of ≤55%.

[0041] Example 1: Municipal Sludge Treatment Raw materials: Concentrated sludge from a wastewater treatment plant, with a moisture content of 97.3% and a CST of 120s; Operating parameters: 0.5MPa × 5 times, with a 2s interval, → 2.0MPa × 3 times, with a 5s interval, → 3.5MPa × 1 time; Results: Sludge cake moisture content 53.2%, CST = 28s; Energy consumption 1.8kWh / ton, traditional filter press 4.5kWh, residual pressure recovery contribution 0.6kWh; Sludge calorific value retention rate 95.4%, original sludge 13.1MJ / kg → treated 12.5MJ / kg.

[0042] Comparison of experimental results: Control group 1: Only a single impact of 3.5 MPa was used, and the moisture content of the mud cake was 72.4%; Control group 2: Traditional Fenton method (Fe2+ 0.1 mol / L, H2O2 0.3 mol / L), cake moisture content 61.5%, but calorific value loss 28%. Example 2: Treatment of oily sludge Raw materials: Petrochemical oily sludge, with a moisture content of 92.5% and an oil content of 15%; Operating parameters: 0.5MPa×6 times → 2.5MPa×4 times → 4.0MPa×1 time; Results: The moisture content of the sludge cake was 48.7%, and the oil content was reduced to 3.2%; the oil recovery rate was >85%.

[0043] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A method for efficient dewatering and conditioning of sludge based on multi-pulse shock waves, characterized in that, It includes sludge pretreatment, multi-pulse shock, and energy recovery dewatering; among which, the multi-pulse shock has a stepped pressure of 0.5-4.0MPa and a pulse frequency of 1-10Hz; the multi-pulse shock includes three stages, in which the first stage is 0.5MPa shock × (3-6) times, with an interval of 2s, to destroy the outer EPS layer; the second stage is 2.0MPa shock × (3-5) times, with an interval of 5s, to break microbial cells; the third stage is 3.5-4MPa shock × 1 time, to release bound water; energy recovery dewatering: using residual pressure to drive the filter press.

2. The method for efficient sludge dewatering and conditioning based on multi-pulse shock waves according to claim 1, characterized in that, The pressure is 0-12 MPa to obtain sludge cake with a moisture content of ≤55%, and the waste heat is used to preheat the sludge to 40-50℃.

3. The method for efficient sludge dewatering and conditioning based on multi-pulse shock waves according to claim 1, characterized in that, Sludge pretreatment: Pump sludge with a moisture content of 95% to 99% into the spherical detonation chamber, let it stand for 5-20 minutes, drain the supernatant, and then fill it again.

4. The method for efficient sludge dewatering and conditioning based on multi-pulse shock waves according to claim 1, characterized in that, The system includes a pulse-type detonation main reaction chamber, an energy recovery system, and an intelligent control system. The pulse-type detonation main reaction chamber comprises a high-pressure gas storage tank, a pulse solenoid valve, and a porous impact plate. The porous impact plate is located inside a spherical detonation chamber. The pulse solenoid valve is located on the pipeline connecting the high-pressure gas storage tank to the spherical detonation chamber, and the porous impact plate is located at the pipeline outlet. The energy recovery system includes a pressure converter and a heat recovery pipe. The pressure converter pressurizes the sludge cake, and the heat recovery pipe heats the incoming sludge. The intelligent control system regulates the pulse frequency and pressure gradient via a PLC. The energy recovery system is connected to the spherical detonation chamber via a pipeline. A heat recovery pipe is located on one side of the pipeline, and a pressure converter and a pressure-driven filter press are sequentially located at the pipeline outlet. The heat recovery pipe is a 316L stainless steel spiral tube with a heat transfer coefficient of 120 W / (m²). 2 ·K); The porous impact plate is evenly distributed with conical micropores, and the inlet diameter D1 and outlet diameter D2 of the conical micropores satisfy D1 / D2=3-5.

5. The method for efficient sludge dewatering and conditioning based on multi-pulse shock waves according to claim 4, characterized in that, The high-pressure gas storage tank is equipped with a vortex cooling device to maintain the gas temperature from -10°C to 5°C.

6. The method for efficient sludge dewatering and conditioning based on multi-pulse shock waves according to claim 4, characterized in that, The outermost part of the spherical detonation chamber is the detonation cavity wall, and an outer wall of the device is provided outside the detonation cavity wall. The space between the detonation cavity wall and the outer wall of the device is filled with shock-absorbing and sound-absorbing filling material. The outer wall of the device is provided with a shock-absorbing support, and a lifting ring is provided on the outer wall of the device.

7. The method for efficient sludge dewatering and conditioning based on multi-pulse shock waves according to claim 4, characterized in that, The spherical detonation chamber is also connected to a sludge inlet pipe and a sludge discharge pipe. The sludge inlet pipe is equipped with a sludge inlet control valve and a flexible damping valve, and the sludge discharge pipe is equipped with a sludge discharge valve and a flexible damping valve. The liquid level and pressure inside the spherical detonation chamber are monitored by a liquid level sensor and a pressure sensor.

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