Bridge stress monitoring device based on microbial fuel cell

Abstract

The invention discloses a bridge stress monitoring device based on a microbial fuel cell, relates to the technical field of bridge safety, and solves the problems that a bridge stress monitoring device in the prior art is short in maintenance period, high in operation and maintenance cost and short in self-energized service life. The device comprises an MFC power generation unit used for generating power by using organic matters and electroactive flora of sludge around the pier, an energy storage unit used for storing energy and boosting, and a stress acquisition unit used for acquiring stress signals, the power supply of the monitoring device depends on the organic matters in the sludge, and the self-energized service life can reach 10-15 years; the whole power generation process does not depend on illumination, wind speed or high-amplitude vibration, the output stability is still kept in dark, high-humidity and underwater static flow environments, and in the operation and maintenance process, only the electrodes need to be periodically checked or replaced, so that the operation and maintenance cost is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of bridge safety, in particular to a bridge stress monitoring device based on a microbial fuel cell. BACKGROUND

[0002] Deep water foundations are commonly used for water-crossing bridges (such as the Qiantang River, Oujiang River, and Zhoushan Sea Bridge Group). The piers are often piled into humus silt layers with a thickness of tens of meters. The layers are characterized by high water content and high organic matter content.

[0003] The humus silt contains electrically active microorganisms (Geobacter, Shewanella, etc.) that are enriched under long-term anaerobic action and provide a continuous source of electron donors. This scarce environment provides unique natural conditions for in-situ power generation by microbial fuel cells (MFCs).

[0004] Continuous observation of stress / strain in the scope of bridge health monitoring must achieve uninterrupted data recording for more than ten years. Traditional power supply methods (wired power supply, chemical batteries, vibration / solar energy harvesting) cannot meet the long-term reliability and economy in high-humidity-low-temperature-shading-underwater environments, which has become a key bottleneck restricting the promotion of the monitoring system.

[0005] In the prior art, the barrel is powered for the monitoring device in the following way:

[0006] 1. Wired power supply scheme: underwater pressure-resistant cables need to be laid and waterproof joints need to be arranged, which has high installation and maintenance costs. The cables are easily locally fatigued or peeled off due to the influence of water flow and drag load, and after failure, the replacement engineering quantity is large and the downtime is long.

[0007] 2. Wireless nodes powered by chemical batteries: disposable lithium batteries or aluminum-air batteries have serious electrode passivation in low-temperature, high-humidity (>95% RH) environments, and the capacity decay rate is much higher than on land. The replacement operation needs manual or ROV submersion operation, which has significant economic and safety burdens.

[0008] 3. Environmental energy harvesting scheme:

[0009] 3.1 Vibration / piezoelectric energy harvesting: the bridge amplitude is a traffic-wind load coupled random process, and the power density difference between day and night is large, so a large capacity energy storage is needed to smooth the power supply gap.

[0010] 3.2 Solar energy harvesting: the bridge bottom structure shielding and water vapor condensation result in insufficient incident irradiance, and panel light decay and surface biological attachment further reduce the output efficiency.

[0011] 3.3 Water flow energy harvesting: small water turbines are easily entangled by floating objects in turbid water, and the maintenance period is short.

[0012] In general, the existing scheme is difficult to achieve the core demand of bridge monitoring, i.e., unattended and more than ten years of self-sustaining energy supply. SUMMARY

[0013] The present application aims to overcome the problems of short maintenance cycle, high operation and maintenance cost, and short self-energy supply life of the bridge stress monitoring device in the prior art, and provides a bridge stress monitoring device based on a microbial fuel cell.

[0014] In a first aspect, a bridge stress monitoring device based on a microbial fuel cell is provided, comprising:

[0015] An MFC power generation unit, the MFC power generation unit comprising a cathode, an anode with oxidation-derived nanoparticle modification, and a sludge matrix located between the cathode and the anode;

[0016] An energy storage unit, the energy storage unit comprising an energy storage subunit for storing the electrical energy generated by the MFC power generation unit and a boost subunit for maintaining the anode potential not lower than -0.4V;

[0017] A stress collection unit, the stress collection unit being configured to collect stress data using the electrical energy stored in the energy storage subunit.

[0018] In some possible implementations, the anode is a porous graphite-carbon felt composite electrode.

[0019] In some possible implementations, the oxidation-derived nanoparticles comprise iron-iron oxide composite nanoparticles.

[0020] In some possible implementations, the anode is buried in the sludge matrix at a depth of 0.5m-1.5m.

[0021] In some possible implementations, the cathode is modified with carbon nanomaterials, transition metal-based catalysts, and conductive polymers.

[0022] In some possible implementations, the electrical conductivity of the pore water in the sludge matrix is 0.5mS / cm-2mS / cm.

[0023] In some possible implementations, the energy storage subunit is a capacitor.

[0024] In some possible implementations, the capacitor is a graphene-activated carbon composite electrode supercapacitor, and the upper limit of the working voltage of the graphene-activated carbon composite electrode supercapacitor is 3V.

[0025] In some possible implementations, the boost subunit is a cold start DC-DC boost chip integrated with an MPPT algorithm, and the MPPT algorithm is configured to maintain the anode potential not lower than -0.4V.

[0026] In some possible implementation manners, the stress collecting unit comprises a strain gauge, a delta-sigma ADC and a deep sleep MCU, an output terminal of the strain gauge is electrically connected with an input terminal of the delta-sigma ADC, an output terminal of the delta-sigma ADC is electrically connected with the deep sleep MCU, the deep sleep MCU collects stress data according to a set using frequency when the voltage of the graphene-activated carbon composite electrode super capacitor is higher than or equal to a first preset value, and the deep sleep MCU enters a deep sleep mode when the voltage of the graphene-activated carbon composite electrode super capacitor is lower than or equal to a second preset value, wherein the first preset value is greater than the second preset value.

[0027] The application has the following beneficial effects: the power supply of the monitoring device in the application relies on the inherent organic matter in the silt, the self-supplying energy life can reach 10-15 years, the entire power generation process does not depend on light, wind speed or high amplitude vibration, and the output stability is maintained in a dark, high-humidity and underwater static flow environment; during operation and maintenance, only the electrodes need to be checked or replaced periodically (5-8 years), and the overall operation and maintenance cost is reduced by more than 60% compared with the pull cable power supply scheme; under the condition of stable power supply, the sampling period can be shortened to the minute level, the dynamic capture of the bridge load-environment coupling response is realized, and thus the timeliness and accuracy of safety warning can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings, which form a part of the present application, are used to provide further understanding of the present application, and the illustrative embodiments of the present application and their descriptions are used to explain the present application, and do not constitute improper limitations to the present application.

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the accompanying drawings needed to be used in the embodiment description will be briefly introduced. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and other accompanying drawings can be obtained by those skilled in the art without any creative effort on the basis of these accompanying drawings.

[0030] Figure 1 is a schematic diagram of a bridge stress monitoring device based on a microbial fuel cell according to Embodiment 1 of the present application;

[0031] Figure 2 is a circuit block diagram of the bridge stress monitoring device based on the microbial fuel cell according to Embodiment 1 of the present application;

[0032] Figure 3 is a power generation principle diagram of the bridge stress monitoring device based on the microbial fuel cell according to Embodiment 1 of the present application.

[0033] Reference signs:

[0034] 100. MFC power generation unit; 101. Cathode; 102. Anode; 103. Silt matrix; 200. Energy storage unit; 201. Energy storage sub-unit; 202. Boost sub-unit; 300. Stress acquisition unit; 301. Strain gauge; 302. ΔΣADC; 303. Deep sleep MCU; 4. Bridge pier. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Example 1

[0037] like Figure 1 As shown, the bridge stress monitoring device based on microbial fuel cells involved in Embodiment 1 of this application includes an MFC power generation unit 100 for generating electricity using the natural organic substrate of silt around the bridge pier 4 and electroactive bacteria, an energy storage unit 200 for storing electrical energy and regulating voltage, and a stress acquisition unit 300 for collecting bridge stress.

[0038] like Figure 2 As shown, the MFC power generation unit 100 includes a cathode 101, an anode 102 modified with oxide-derived nanoparticles, and a sludge matrix 103 located between the cathode 101 and the anode 102, as shown. Figure 3 As shown, the anode 102 is buried in the sludge substrate 103 under anaerobic conditions. Electroactive bacteria on the anode 102 utilize the organic matter in the sludge substrate 103 for growth and metabolism, releasing electrons and protons (i.e., hydrogen ions) in the process. The anode 102 acts as an electron acceptor, receiving electrons and transferring them to the cathode 101 through an external circuit and load. Protons (i.e., hydrogen ions) diffuse to the cathode 101 unit via the mud / water interface. In the cathode 101, electrons and protons undergo a reduction reaction with the final electron acceptor to generate water. The redox potential difference between the anode 102 and the cathode 101 forms an output voltage, realizing the power generation function.

[0039] In this embodiment, the anode 102 of the MFC power generation unit 100 adopts a porous graphite-carbon felt composite electrode, and iron-iron oxide composite nanoparticles are used to modify the anode 102 to enhance the surface wettability of the anode 102 and the adhesion of microorganisms on the electrode surface, and reduce the electron transfer resistance in the anode 102, thereby increasing the current density and output power of the SMFC. In use, the anode 102 is buried in the silt matrix 103 around the bridge pier 4 at a depth of 0.5m–1.5m.

[0040] The cathode 101 of the MFC power generation unit 100 employs carbon nanomaterials, transition metal-based catalysts, and carbon-based materials modified with conductive polymers. These carbon-based materials include carbon cloth, carbon felt, and graphite. Dissolved oxygen (DO) in river water is the most common electron acceptor in the cathode 101. The surface defects and functional groups of carbon-based materials (such as carbon cloth, carbon felt, and graphite) provide ORR catalytic active sites, lowering the reaction energy barrier. Compared to precious metals (platinum), the carbon-based cathode 101 is less expensive and more resistant to impurities in river water (such as organic matter and chloride ions), making it less prone to poisoning and deactivation. Furthermore, carbon-based materials exhibit far superior corrosion resistance compared to metal electrodes, preventing oxidation and dissolution, thus avoiding the release of heavy metal ions and water pollution. Additionally, the high specific surface area of ​​carbon-based materials such as carbon cloth, carbon felt, and graphite significantly increases the oxygen adsorption and reaction interface, enhancing the reaction rate of the cathode 101. The porous structure promotes the diffusion of dissolved oxygen from the water into the electrode interior, overcoming the localized oxygen deficiency problem caused by uneven river flow.

[0041] The silt matrix 103 serves as a natural electrolyte membrane, allowing for ion conduction: pore water (with a conductivity of 0.5 mS / cm-2 mS / cm) provides migration channels for protons and other cations, achieving charge balance. Physical isolation: a vertical distance of several tens of centimeters inhibits oxygen backflow into the anode 102, preventing oxygen poisoning in the anode 102 region; no additional PEM or ceramic separator is required, thus simplifying the structure and reducing internal resistance.

[0042] like Figure 2 As shown, the energy storage unit 200 includes an energy storage sub-unit 201 for storing the electrical energy generated by the MFC power generation unit 100 and a boost sub-unit 202 for maintaining the potential of the anode 102 at no less than -0.4V.

[0043] In this embodiment, a 10F-20F graphene-activated carbon composite electrode supercapacitor is used to collect the electrical energy generated by the MFC power generation unit 100. This stage can also be called the energy collection stage. The upper limit of the operating voltage of the graphene-activated carbon composite electrode supercapacitor is 3.0V.

[0044] In order to maintain the potential of the anode 102, a 0.18V cold start DC-DC boost chip is selected as the boost subunit 202, which is integrated with impedance matching-maximum power point tracking (MPPT) algorithm for maintaining the potential of the anode 102 not lower than-0.4V.

[0045] The stress acquisition unit 300 is used for acquiring stress data by using the electric energy stored in the energy storage subunit 201. Figure 2 As shown, the stress acquisition unit 300 includes a strain gauge 301 for acquiring bridge stress, a delta sigma ADC 302 for analog-digital conversion, and a deep sleep MCU 303 for signal sampling, the output end of the strain gauge 301 is electrically connected with the input end of the delta sigma ADC 302, the output end of the delta sigma ADC 302 is electrically connected with the deep sleep MCU 303, the initial sampling frequency of the deep sleep MCU 303 is 10 minutes / time, the sampling frequency of the deep sleep MCU 303 can be customized and adjusted by the user, the adjustment mode can be adjusted on site through the communication line or adjusted remotely through the network, the deep sleep MCU 303 acquires stress data according to the set sampling frequency when the voltage of the graphene-activated carbon composite electrode supercapacitor is higher than or equal to the first preset value, the deep sleep MCU 303 enters the deep sleep mode when the voltage of the graphene-activated carbon composite electrode supercapacitor is lower than or equal to the second preset value, wherein the first preset value is greater than the second preset value, for example, the first preset value is 2.6V and the second preset value is 2.2V.

[0046] In use, the power generation box composed of the cathode 101 and the anode 102 is inserted into the silt near the pier 4, so that the anode 102 is located inside the silt and the cathode 101 is located in the water area above the silt, an electrochemical reaction is excited by using the oxygen potential difference of water body-silt, and the electroactive bacteria form a biofilm on the surface of the anode 102, and a stable current density (1-2mA / cm²) can be reached after 2-4 weeks.

[0047] When the voltage of the graphene-activated carbon composite electrode supercapacitor is greater than or equal to 2.6V, the deep sleep MCU 303 activates the signal acquisition task and acquires stress signals according to the default or user-set sampling frequency; when the voltage of the graphene-activated carbon composite electrode supercapacitor is less than or equal to 2.2V, the deep sleep MCU 303 enters the deep sleep mode.

[0048] In the embodiment, by establishing remote communication between the deep sleep MCU 303 and the cloud platform, the cloud platform can receive and record the bridge stress data in real time, as well as the health parameters of the MFC power generation unit 100 such as internal resistance and open circuit voltage, to provide basis for structural safety evaluation and operation and maintenance decision of the stress monitoring device. By monitoring the internal resistance and open circuit voltage of the MFC power generation unit, the sludge organic load and microbial activity can be indirectly evaluated, and the integration of structural health and environmental monitoring is realized.

[0049] The stress monitoring device in the embodiment generates electricity by relying on the organic matter in the sludge, has super-long endurance, and the self-powered life is expected to reach 10-15 years. The electricity generation process does not depend on factors such as light, wind speed or high amplitude vibration, and the output stability (power density fluctuation amplitude < 15%) is maintained in dark, high humidity and underwater static flow environments. In terms of operation and maintenance, only the electrode box needs to be checked or replaced periodically (5-8 years), and the overall operation and maintenance cost is reduced by more than 60% compared with the catenary power supply scheme, and the operation and maintenance cost is extremely low. Secondly, the anaerobic oxidation of humus by the anode 102 biofilm can simultaneously reduce the chemical oxygen demand (COD) in the water-sludge system, has the function of in-situ repair, realizes ecological synergistic benefit, and in addition, the stable power supply of the MFC power generation unit 100 allows the sampling period to be shortened to minutes, realizes dynamic capture of the bridge load-environment coupling response, and improves the timeliness and accuracy of safety warning.

[0050] The above is only a preferred specific embodiment of the present application; however, the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed in the present application, according to the technical solution and improvement concept of the present application, can be equivalent to replace or change, which should be covered in the protection scope of the present application.

Claims

1. A bridge stress monitoring device based on microbial fuel cells, characterized in that, include: MFC power generation unit, the MFC power generation unit includes a cathode, an anode modified with oxide-derived nanoparticles and a sludge matrix located between the cathode and the anode; The energy storage unit includes an energy storage sub-unit for storing electrical energy generated by the MFC power generation unit and a boost sub-unit for maintaining the anode potential at no less than -0.4V; A stress acquisition unit is used to acquire stress data using the electrical energy stored in the energy storage subunit.

2. The bridge stress monitoring device based on microbial fuel cells according to claim 1, characterized in that, The anode is a porous graphite-carbon felt composite electrode.

3. The bridge stress monitoring device based on microbial fuel cells according to claim 1 or 2, characterized in that, The oxidation-derived nanoparticles include iron-iron oxide composite nanoparticles.

4. The bridge stress monitoring device based on microbial fuel cells according to claim 3, characterized in that, The anode is buried at a depth of 0.5m-1.5m in the silt matrix.

5. The bridge stress monitoring device based on microbial fuel cells according to any one of claims 1, 2, and 4, characterized in that, The cathode is made of carbon nanomaterials, transition metal-based catalysts, and carbon-based materials modified with conductive polymers.

6. The bridge stress monitoring device based on microbial fuel cells according to claim 5, characterized in that, The electrical conductivity of the pore water in the silt matrix is ​​0.5 mS / cm to 2 mS / cm.

7. The bridge stress monitoring device based on microbial fuel cells according to claim 1 or 6, characterized in that, The energy storage sub-unit is a capacitor.

8. The bridge stress monitoring device based on microbial fuel cells according to claim 7, characterized in that, The capacitor is a graphene-activated carbon composite electrode supercapacitor, and the upper limit of the operating voltage of the graphene-activated carbon composite electrode supercapacitor is 3V.

9. The bridge stress monitoring device based on microbial fuel cells according to claim 8, characterized in that, The boost subunit is a cold-start DC-DC boost chip with an integrated MPPT algorithm, which is used to maintain the anode potential at no less than -0.4V.

10. The bridge stress monitoring device based on microbial fuel cells according to claim 8, characterized in that, The stress acquisition unit includes a strain gauge, a ΔΣADC, and a deep sleep MCU. The output terminal of the strain gauge is electrically connected to the input terminal of the ΔΣADC, and the output terminal of the ΔΣADC is electrically connected to the deep sleep MCU. The deep sleep MCU acquires stress data at a set acquisition frequency when the voltage of the graphene-activated carbon composite electrode supercapacitor is higher than or equal to a first preset value. The deep sleep MCU enters a deep sleep mode when the voltage of the graphene-activated carbon composite electrode supercapacitor is lower than or equal to a second preset value, wherein the first preset value is greater than the second preset value.

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