Control method and system for energy self-sufficient compressed air supply

Abstract

The invention provides a control method and system for energy self-sufficient compressed air supply. By sensing the state of the biogas in real time and intelligently controlling the dynamic coupling mechanism, efficient coupling between unstable biogas energy and a high-reliability compressed air system is achieved. According to the invention, biogas which is traditionally regarded as waste is converted into stable driving energy, so that the dependence on an external power grid is remarkably reduced, and the energy self-sufficiency rate of the system is improved; meanwhile, by flexibly adjusting the output proportion of the double power sources, it is ensured that power input of the compressor unit is continuous and stable, aeration process instability and equipment loss caused by air source fluctuation are fundamentally avoided, and finally reliable operation of a sewage treatment core process is ensured while energy conservation and consumption reduction are achieved.

Description

Technical Field

[0001] This invention relates to the technical field of compressed air supply control, and specifically to a control method and system for energy-self-sufficient compressed air supply. Background Technology

[0002] The aeration system is the core energy-consuming component of the activated sludge biological treatment unit. It provides oxygen for the metabolism of aerobic microorganisms by injecting compressed air into the aeration tank. Traditional aeration systems generally use equipment such as centrifugal blowers or Roots blowers directly powered by the municipal power grid. Although this energy supply method is stable, it results in wastewater treatment plants operating as large electricity consumers for a long time, leading to high energy costs and indirectly generating a large amount of carbon emissions due to reliance on fossil fuel power generation.

[0003] Meanwhile, the wastewater treatment process itself, especially in the anaerobic digestion stage of sludge, generates a large amount of methane-rich biogas. This biogas, as a potential renewable energy source with considerable calorific value, should be an important energy source within the plant, achieving an energy cycle of treating waste with waste. However, in the practice of related technologies, directly using biogas to drive compressed air systems faces significant technical bottlenecks.

[0004] In related technologies, the compressed air system of a wastewater treatment plant faces the challenge of safely, reliably, and efficiently coupling biogas energy, whose output and quality are unstable, to a compressed air supply system that requires a stable power input. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and provide a control method and system for energy self-sufficient compressed air supply, so as to solve the problem in the related technology that: the compressed air system of sewage treatment plant has difficulty in safely, reliably and efficiently coupling biogas energy with unstable output and quality to the compressed air supply system that requires stable power input.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a control method for an energy-self-sufficient compressed air supply, executed by a controller, the method comprising: The state parameters of biogas generated by the wastewater treatment facility are acquired in real time; wherein, the state parameters include at least the biogas flow rate and methane concentration. Based on the state parameters, determine whether the preset internal combustion engine starting conditions are met; When the internal combustion engine start-up conditions are met, a power distribution control command is generated and sent to a preset power coupling mechanism. The power distribution control command controls the operating state of the preset power coupling mechanism to dynamically adjust the power output ratio of the internal combustion engine driven by biogas and the electric motor driven by the power grid to the compressor unit. The power coupling mechanism is a transmission device configured between the internal combustion engine, the electric motor, and the compressor unit input shaft to achieve flexible coupling and stepless adjustment of the power output from the internal combustion engine and the electric motor.

[0007] Furthermore, the step of acquiring the state parameters of biogas generated by the wastewater treatment facility in real time includes: Acquire raw data obtained from real-time monitoring of biogas using preset sensing devices; Perform a validity check on the original data, and use the data that passes the check as the status parameter.

[0008] Further, the step of determining whether the preset internal combustion engine starting conditions are met based on the state parameters includes: The gas flow rate is compared with a preset first flow rate threshold, and the methane concentration is compared with a preset first concentration threshold; If the gas flow rate continuously exceeds the first flow rate threshold and the methane concentration continuously exceeds the first concentration threshold, and both reach a preset stable duration, then the internal combustion engine starting conditions are determined to be met.

[0009] Further, the step of generating a power distribution control command and sending it to a preset power coupling mechanism when the internal combustion engine starting conditions are met includes: Calculate the current maximum available power of the internal combustion engine based on the gas flow rate and methane concentration; Based on the current maximum available power and the real-time power demand of the compressor unit, a first target output power of the internal combustion engine and a second target output power of the electric motor are determined; wherein, the first target output power is configured to characterize the output power that the internal combustion engine is expected to undertake under the current biogas state, and the second target output power is configured to characterize the output power that the electric motor needs to undertake to make up for the difference between the first target output power and the real-time power demand; Based on the first target output power and the second target output power, control commands are generated to adjust the operating state of the power coupling mechanism.

[0010] Further, the step of determining the first target output power of the internal combustion engine and the second target output power of the electric motor based on the current maximum available power and the real-time power demand of the compressor unit includes: Compare the current maximum available power with the real-time power demand; When the current maximum available power is greater than or equal to the real-time power requirement, the first target output power is set to the real-time power requirement, and the second target output power is set to zero. When the current maximum available power is less than the real-time power demand, a preset efficiency optimization algorithm is executed to determine the optimal output power value of the internal combustion engine within the range of the current maximum available power, and the optimal output power value is set as the first target output power, and the difference between the real-time power demand and the first target output power is set as the second target output power; wherein, the efficiency optimization algorithm is configured to determine the optimal output power value with the goal of achieving the highest overall operating efficiency of the internal combustion engine under the current biogas state.

[0011] Further, the step of executing a preset efficiency optimization algorithm when the current maximum available power is less than the real-time power demand to determine the optimal output power value of the internal combustion engine within the range of the current maximum available power, setting the optimal output power value as the first target output power, and setting the difference between the real-time power demand and the first target output power as the second target output power includes: Based on the methane concentration and the gas flow rate, by querying a pre-established efficiency model that reflects the relationship between the efficiency and output power of the internal combustion engine under different gas conditions, the optimal efficiency operating point of the internal combustion engine within the current maximum available power range is determined. The power value corresponding to the optimal efficiency operating point is set as the optimal output power value.

[0012] Secondly, the present invention provides an energy-self-sufficient compressed air supply system comprising: A biogas supply unit is used to collect and purify biogas generated by a wastewater treatment facility and output the state parameters of the biogas, which include at least the gas flow rate and methane concentration. The drive module includes an internal combustion engine driven by biogas, an electric motor driven by the power grid, and a power coupling mechanism. The output shafts of the internal combustion engine and the electric motor are connected to the input shaft of the compressor unit through the power coupling mechanism to jointly drive the compressor unit to operate. The controller is connected to the biogas supply circuit and the drive module respectively, and is used to execute the above-described control method for energy self-sufficient compressed air supply.

[0013] Furthermore, the biogas supply unit comprises the following components connected sequentially along the gas flow direction: A gas-liquid separator is used to remove liquid water and large particulate impurities from the biogas. A drying tower is used to lower the dew point of the biogas. Desulfurization tower, used to remove hydrogen sulfide from the biogas; The power coupling mechanism is a hydraulic coupling.

[0014] Thirdly, the present invention provides an electronic device, comprising: a memory, and one or more processors communicatively connected to the memory; the memory stores instructions executable by the one or more processors, the instructions being executed by the one or more processors to cause the one or more processors to implement the method described above.

[0015] Fourthly, the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method.

[0016] Beneficial effects: This invention achieves efficient coupling between unstable biogas energy and a highly reliable compressed air system by real-time sensing of biogas status and intelligent control of the power coupling mechanism. This embodiment converts biogas, traditionally considered waste, into a stable driving energy source, significantly reducing dependence on the external power grid and improving the system's energy self-sufficiency. Simultaneously, by flexibly adjusting the output ratio of the two power sources, it ensures a continuous and stable power input to the compressor unit, fundamentally avoiding instability in the aeration process and equipment wear caused by fluctuations in the gas source. Ultimately, it achieves energy conservation and consumption reduction while ensuring the reliable operation of the core wastewater treatment process. Attached Figure Description

[0017] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic flowchart of a control method for energy-self-sufficient compressed air supply provided by an embodiment of the present invention; Figure 2 This is a block diagram of an energy-self-sufficient compressed air supply system used in an embodiment of the present invention; Figure 3 This is a block diagram of an electronic device used in an embodiment of the present invention. Detailed Implementation

[0018] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0019] The following detailed description is exemplary and intended to provide further detailed explanation of the invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this invention is for describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention.

[0020] In related technologies, compressed air supply is the core component of the aeration process in wastewater treatment plant operations, often accounting for over 60% of the plant's total energy consumption and representing a major source of operating costs. Simultaneously, the anaerobic digestion stage in wastewater treatment continuously generates biogas (primarily methane), a renewable on-site energy source. Traditional compressed air supply systems are typically driven by grid-powered electric motors, offering stable operation but incurring high energy costs. While some advanced plants have attempted to utilize biogas-powered internal combustion engines as auxiliary power, this approach faces fundamental technical challenges in practical applications.

[0021] The relevant technologies face several key challenges and pain points that urgently need to be addressed: First, the yield and quality of biogas (e.g., methane concentration) are significantly intermittent and fluctuating due to various factors such as influent load, temperature, and microbial activity, directly leading to unstable output power of the internal combustion engine. Second, coupling such an unstable power source with a high-speed compressor requiring constant speed and torque is extremely challenging. Common rigid connections or simple switching mechanisms cause drastic changes in the compressor unit's input speed and torque when the gas source fluctuates, resulting not only in outlet pressure fluctuations and decreased aeration efficiency but also in mechanical stress shocks, accelerating equipment wear and even threatening the stable operation of the entire biochemical treatment process. The core issue lies in the lack of a collaborative control mechanism capable of dynamic energy management and flexible transfer between fluctuating gas sources and stable loads.

[0022] Ultimately, the aforementioned technical problems stem from two levels: firstly, at the control level, the system failed to proactively assess the state of biogas and formulate an optimal energy distribution strategy accordingly; secondly, at the mechanical level, there was a lack of transmission devices capable of absorbing power fluctuations and achieving stepless smooth power distribution, in conjunction with precise control.

[0023] To address this core technical challenge, this invention proposes an innovative solution. The inventive concept is to monitor the state parameters of biogas in real time and generate intelligent control commands based on this, thereby driving a dedicated power coupling mechanism to dynamically adjust the power output ratio between the gas internal combustion engine and the grid motor. This allows the unstable biogas energy to be safely, reliably, and efficiently integrated into a compressed air supply system that requires stable operation.

[0024] This embodiment provides a control method for energy-self-sufficient compressed air supply, which is executed by a controller. The controller may be a programmable logic controller (PLC), an industrial computer (IPC), or other embedded control system with data acquisition, logic operation, and instruction output functions.

[0025] like Figure 1 and Figure 2 As shown, the method may include: Step S12: Acquire the state parameters of biogas generated by the wastewater treatment facility in real time; wherein the state parameters include at least the biogas flow rate and methane concentration.

[0026] In this embodiment, the real-time acquisition action can be represented as the controller continuously reading data from the front-end sensing device through its analog input module or communication interface at a sampling frequency of not less than once per second.

[0027] In this embodiment, the state parameters can be physical quantities that directly or indirectly reflect the energy content and supply stability of biogas. Specifically, they can include biogas flow rate and methane concentration. Specifically, the biogas flow rate can be obtained through a flow metering device installed on the biogas delivery pipeline. This flow metering device can be an orifice plate flow meter, a vortex flow meter, or a thermal mass flow meter. Its output signal can be a standard analog current signal (e.g., 4-20mA) or a digital bus signal (e.g., Modbus, PROFIBUS DP), which can be received by the controller's input module. The methane concentration can be determined by an online gas composition analyzer installed on the biogas pipeline. This online gas composition analyzer can be an infrared gas analyzer based on the non-dispersive infrared (NDIR) principle or an online chromatograph based on the gas chromatography (GC) principle. This online gas composition analyzer can transmit the real-time methane concentration value to the controller via communication.

[0028] In this embodiment, the state parameters may further include gas pressure and gas temperature, etc. For example, the corresponding signals can be obtained through a pressure transmitter and a platinum resistance temperature sensor (Pt100) to provide a more comprehensive data basis for subsequent judgment.

[0029] Step S14: Based on the state parameters, determine whether the preset internal combustion engine starting conditions are met.

[0030] In this embodiment, the preset internal combustion engine starting conditions include at least a first flow rate threshold and a first concentration threshold. These thresholds can be predetermined and set based on the minimum stable operating load requirements and fuel quality requirements of the internal combustion engine model used, through experiments or equipment manuals. For example, the first flow rate threshold can be set to a gas flow rate value that supports the internal combustion engine to output 20% of its rated power, and the first concentration threshold can be set to a 50% volume concentration.

[0031] The judgment process may specifically include the following sub-steps: First, the real-time gas flow rate is compared with a first flow rate threshold; simultaneously, the real-time methane concentration is compared with a first concentration threshold.

[0032] Then, to ensure reliable startup and avoid frequent start-stop cycles of the internal combustion engine due to instantaneous parameter fluctuations, a preset stabilization period (e.g., 5 minutes) can be introduced into the decision logic. The controller only determines that the internal combustion engine startup conditions are met when both the gas flow rate and methane concentration consistently exceed the first flow rate threshold for this stabilization period. This sustained exceedance can be represented as all sampling points (or data points filtered by moving average) exceeding the threshold value within the stabilization period.

[0033] Step S16: When the internal combustion engine starting conditions are met, a power distribution control command is generated and sent to a preset power coupling mechanism; wherein, the power distribution control command is used to control the operating state of the preset power coupling mechanism to dynamically adjust the power output ratio of the internal combustion engine driven by biogas and the electric motor driven by the power grid to the compressor unit; wherein, the power coupling mechanism is a transmission device configured between the internal combustion engine, the electric motor and the input shaft of the compressor unit to realize flexible coupling and stepless adjustment of the output power of the internal combustion engine and the electric motor.

[0034] In this embodiment, the generated power distribution control command can be expressed as the controller calculating the target output power that the internal combustion engine and the electric motor each need to undertake in order to achieve the real-time power demand of the compressor unit, based on an internally preset optimization model (e.g., calculation based on power balance relationship or real-time solution based on optimization algorithm).

[0035] The power distribution control command may be a target speed setpoint, torque limit value, or power distribution ratio coefficient (e.g., 0%-100%) sent to the power coupling device.

[0036] In this embodiment, the power coupling mechanism can be a mechanical device that realizes flexible coupling and stepless adjustment of dual power sources. It can be a transmission mechanism capable of receiving power inputs from both an internal combustion engine and an electric motor, and capable of steplessly adjusting the combined ratio of the two power sources on the output shaft according to instructions.

[0037] In one possible and specific implementation, the power coupling mechanism may be a hydraulic coupling, which can steplessly change the transmitted torque by adjusting the filling rate in the working chamber.

[0038] In one possible and specific implementation, the power coupling mechanism may be a magnetic powder clutch or an electromagnetic slip clutch, which can steplessly control the transmitted torque by adjusting the excitation current.

[0039] In one possible and specific implementation, the power coupling mechanism may be a planetary gear differential merging mechanism, which can steplessly adjust the power combining ratio of the two active power sources (internal combustion engine and main motor) at the output end by controlling the speed and direction of the speed regulating motor (e.g., servo motor) at one of the input ends.

[0040] In this embodiment, the controller can send the generated control commands to the electronic control unit (ECU) integrated into the power coupling mechanism or directly drive its electro-hydraulic actuator via its analog output module (outputting 4-20mA or 0-10V signals) or communication interface (sending data frames including set values). The power coupling mechanism can adjust its internal state in real time according to the received commands (e.g., the opening of the hydraulic coupling conduit, the excitation current of the electromagnetic clutch, etc.), thereby achieving dynamic and stepless adjustment of the power output ratio between the internal combustion engine and the electric motor.

[0041] This embodiment achieves efficient coupling between unstable biogas energy and a highly reliable compressed air system by real-time sensing of biogas status and intelligent control of the power coupling mechanism. This embodiment converts biogas, traditionally considered waste, into a stable driving energy source, significantly reducing dependence on the external power grid and improving the system's energy self-sufficiency rate. Simultaneously, by flexibly adjusting the output ratio of the two power sources, it ensures a continuous and stable power input to the compressor unit, fundamentally avoiding instability in the aeration process and equipment wear caused by fluctuations in the gas source. Ultimately, it achieves energy conservation and consumption reduction while ensuring the reliable operation of the core wastewater treatment process.

[0042] In some embodiments, the step of acquiring the state parameters of biogas generated by the wastewater treatment facility in real time includes: Step S122: Obtain raw data obtained by real-time monitoring of biogas through a preset sensing device.

[0043] In this embodiment, a flow sensor installed on the biogas delivery pipeline can be used to obtain raw biogas flow data. Specifically, it can be a vortex flow meter, which measures flow by detecting the vortex frequency generated when fluid passes through a blunt body and outputs a pulse frequency signal or analog current signal (e.g., 4-20mA) linearly related to the instantaneous flow value. Alternatively, it can be a thermal mass flow meter, which measures flow by measuring the temperature change caused by fluid flowing through a thermistor or the energy required to maintain a constant temperature and outputs an analog voltage signal (e.g., 0-5V) or a digital signal (e.g., transmitted via an RS-485 interface following the Modbus-RTU protocol). To obtain raw methane concentration data, an online gas analyzer installed in the biogas pipeline bypass sampling system can be used.

[0044] In this embodiment, the controller can receive the analog current or voltage signal described above through the input module. This module can convert the analog signal into a digital quantity or receive digital messages through its serial communication interface (e.g., RS-485) or industrial Ethernet interface (e.g., Ethernet), and extract the measurement data value therein by parsing a predefined communication protocol (e.g., Modbus).

[0045] Step S124: Perform a validity check on the original data and use the data that passes the check as the status parameter.

[0046] In this embodiment, the validity check can be a range check. Specifically, the controller can compare the read raw data value with a preset reasonable range threshold. For example, for a flow meter with a range of 0-1000 m³ / h, its reasonable range can be set to 5-950 m³ / h. If the data value exceeds this range, the data is determined to be invalid.

[0047] In this embodiment, the validity verification can be a rate of change verification. Specifically, the controller can calculate the rate of change (first-order difference) of the original data within adjacent sampling periods and compare it with a preset maximum allowable rate of change threshold. For example, a change in methane concentration exceeding 5% volume fraction / second within 1 second is considered an abnormal mutation, and the data is deemed unreliable.

[0048] In this embodiment, for data that is determined to be invalid, the controller can directly discard the invalid data and replace it with the previous valid sample value. Alternatively, when multiple invalid data appear consecutively, a linear interpolation or moving average algorithm can be used to calculate a reasonable replacement value based on the valid historical data before and after it.

[0049] In some implementations, the step of determining whether the preset internal combustion engine starting conditions are met based on the state parameters includes: Step S142: Compare the gas flow rate with a preset first flow rate threshold, and compare the methane concentration with a preset first concentration threshold; In this embodiment, the first flow rate threshold can be set based on the minimum gas supply required to ensure the internal combustion engine can start and maintain a minimum stable operating power. This threshold can be specifically determined through engineering calculations and experiments based on the technical specifications (minimum gas consumption rate) provided by the internal combustion engine manufacturer and the margin requirements of the specific application scenario. The first concentration threshold can be set based on the minimum gas quality required to ensure the internal combustion engine can ignite normally, burn stably, and meet emission standards.

[0050] Step S144: If the gas flow rate continuously exceeds the first flow rate threshold and the methane concentration continuously exceeds the first concentration threshold, and both reach a preset stable duration, then it is determined that the internal combustion engine start-up conditions are met.

[0051] In this embodiment, the stabilization duration is a time parameter, for example, 10 minutes. It can be set based on a time constant that takes into account the changes in biogas production rate and composition during wastewater treatment, with the aim of ensuring that the observed gas combustion state represents a stable trend rather than a brief peak.

[0052] In some embodiments, the step of generating a power distribution control command and sending it to a preset power coupling mechanism when the internal combustion engine starting conditions are met includes: Step S162: Calculate the current maximum available power of the internal combustion engine based on the gas flow rate and methane concentration; In this embodiment, the current maximum available power can be expressed as the maximum mechanical power that the internal combustion engine can theoretically stably output under the current biogas flow rate and methane concentration.

[0053] In this embodiment, the controller can pre-store a calculation model. Specifically, the controller first calculates the lower heating value of the current gas (e.g., heating value = methane concentration × methane unit heating constant) and the total thermal power (total thermal power = gas flow rate × lower heating value) based on the real-time methane concentration and gas flow rate. Subsequently, the calculation model can multiply the total thermal power by a preset average power generation efficiency of the internal combustion engine (e.g., a fixed value or interpolation table determined based on the efficiency curve of this type of internal combustion engine under typical load) to obtain the current maximum available power.

[0054] Step S164: Based on the current maximum available power and the real-time power demand of the compressor unit, determine the first target output power of the internal combustion engine and the second target output power of the electric motor; wherein, the first target output power is configured to characterize the output power that the internal combustion engine is expected to undertake under the current biogas state, and the second target output power is configured to characterize the output power that the electric motor needs to undertake to make up for the difference between the first target output power and the real-time power demand.

[0055] In this embodiment, the real-time power requirement of the compressor unit is obtained through one of the following methods: Power setpoints sent by the host control system that controls the operation of the compressor unit via a communication network (e.g., PROFIBUS DP); The power demand is calculated in real time by the controller based on the dissolved oxygen measurement value of the aeration tank using a PID control algorithm.

[0056] In this embodiment, when the current maximum available power is greater than or equal to the real-time power demand, the controller can set the first target output power to be equal to the real-time power demand. That is, the current biogas energy is sufficient to fully meet the compressor's power requirements. Simultaneously, the controller sets the second target output power to zero, indicating that the motor does not need to output power.

[0057] In this embodiment, when the current maximum available power is less than the real-time power demand, the controller can initiate an optimized allocation strategy. In this case, the controller can set a first target output power as an optimized value, which is not greater than the current maximum available power. In one possible and specific implementation, the first target output power can be set to the current maximum available power. In another possible and specific implementation, a further efficiency optimization algorithm can be executed (e.g., querying the optimal efficiency point power of the internal combustion engine under this gas state), setting the first target output power to the optimal efficiency point power, but ensuring that this value does not exceed the current maximum available power as a constraint. Then, the controller can calculate the difference between the real-time power demand and the first target output power, and set this difference as a second target output power, indicating that the motor needs to supplement the insufficient power.

[0058] Step S166: Generate control commands for adjusting the operating state of the power coupling mechanism based on the first target output power and the second target output power.

[0059] In this embodiment, the generated control command can be represented as the controller converting the calculated target power value into a physical signal that can be recognized and executed by the electronic control unit (ECU) of the power coupling mechanism or by directly driving its actuator.

[0060] In this embodiment, for the hydraulic coupling, the control command can be sent to its electro-hydraulic actuator, which is a duty cycle setting value of a 4-20mA analog current signal or a pulse width modulation (PWM) signal corresponding to the target filling rate.

[0061] For planetary gear mechanisms that use speed-regulating motors for power confluence, the control command can be a speed setpoint or torque limit value sent to the speed-regulating motor driver.

[0062] This embodiment calculates the current maximum available power of biogas in real time and precisely allocates the target output power of the internal combustion engine and electric motor accordingly. Its beneficial effect lies in achieving accurate quantification and efficient utilization of the unstable biogas energy potential, ensuring that the compressor unit always receives a stable power input precisely matched to real-time demand. Simultaneously, by prioritizing and maximizing the use of internal combustion engine power supplemented precisely by electric motor power, the system significantly reduces dependence on the external power grid while ensuring the stability of the aeration process, thereby improving the system's energy self-sufficiency and operational economy.

[0063] In some implementations, the step of determining the first target output power of the internal combustion engine and the second target output power of the electric motor based on the current maximum available power and the real-time power demand of the compressor unit includes: Step S1642: Compare the current maximum available power with the real-time power demand.

[0064] In one possible and specific implementation, the controller can read the current maximum available power value calculated in step S162 from its data register, and simultaneously obtain a value representing the real-time power demand.

[0065] In one possible and specific implementation, the real-time power demand can be obtained by receiving a setpoint from a host monitoring system via a communication bus (e.g., PROFIBUS DP). Alternatively, the pressure-flow regulation algorithm built into the controller can be used to calculate the value based on the deviation between the real-time dissolved oxygen concentration in the aeration tank and the set value. Alternatively, it can be obtained directly from a table of preset power demand curves related to the amount of water to be treated.

[0066] In one possible and specific implementation, the controller can perform a subtraction operation through its arithmetic logic unit (ALU) to calculate the difference between the current maximum available power and the real-time power demand. The magnitude of the difference can be determined by whether it is positive, negative, or zero.

[0067] Step S1644: When the current maximum available power is greater than or equal to the real-time power requirement, set the first target output power to the real-time power requirement and set the second target output power to zero.

[0068] Step S1646: When the current maximum available power is less than the real-time power demand, a preset efficiency optimization algorithm is executed to determine the optimal output power value of the internal combustion engine within the range of the current maximum available power, and the optimal output power value is set as the first target output power, and the difference between the real-time power demand and the first target output power is set as the second target output power; wherein, the efficiency optimization algorithm is configured to determine the optimal output power value with the goal of achieving the highest comprehensive operating efficiency of the internal combustion engine under the current biogas state.

[0069] In this embodiment, the preset efficiency optimization algorithm can be an efficiency MAP query algorithm. Specifically, the controller can pre-store the universal characteristic curve (efficiency MAP) of the internal combustion engine calibrated through bench tests. This MAP can be a three-dimensional data table, with gas flow rate, methane concentration, and output power as input variables, and the corresponding internal combustion engine operating efficiency as the output value. The controller can use the current gas flow rate and methane concentration as fixed inputs, and perform scanning or interpolation calculations within the power range bounded by zero to the current maximum available power to find the point with the highest efficiency value, and determine the power value corresponding to that point as the optimal output power value.

[0070] In this embodiment, the preset efficiency optimization algorithm can be a model-based prediction optimization algorithm. Specifically, the controller can have a built-in empirical model or polynomial fitting formula for the efficiency of the internal combustion engine. This model can describe the functional relationship between efficiency and output power under a given gas composition. The controller can use this model to solve for the maximum value of the efficiency function in real time within the power domain [0, current maximum available power] using a one-dimensional optimization algorithm (e.g., the golden section method or gradient method), and determine the power value at that point as the optimal output power value.

[0071] This implementation method introduces an efficiency optimization algorithm to dynamically optimize and lock the internal combustion engine's most efficient operating point under a specific gas state when the biogas power is insufficient to meet the full load demand. This implementation method ensures that the system can maintain the internal combustion engine operating in the optimal efficiency range even under partial load conditions, thereby significantly improving the conversion and utilization efficiency of biogas energy. At the same time, while ensuring a stable supply of compressed air, it minimizes the demand for compensation electricity from the external power grid, achieving a balance between energy utilization economy and system operation stability.

[0072] In some implementations, the step of executing a preset efficiency optimization algorithm when the current maximum available power is less than the real-time power demand to determine the optimal output power value of the internal combustion engine within the range of the current maximum available power, setting the optimal output power value as the first target output power, and setting the difference between the real-time power demand and the first target output power as the second target output power includes: Step S16462: Based on the methane concentration and the gas flow rate, by querying a pre-established efficiency model that reflects the relationship between the efficiency and output power of the internal combustion engine under different gas conditions, determine the optimal efficiency operating point of the internal combustion engine within the current maximum available power range.

[0073] In this embodiment, the efficiency model can be a data structure pre-built in the controller's memory, capable of characterizing the relationship between the engine's operating efficiency and variations in gas state parameters (methane concentration, gas flow rate) and output power within the engine's operating range. The controller can access and process this efficiency model using the currently acquired methane concentration and gas flow rate as input conditions to find the optimal solution under given constraints. The optimal efficiency operating point can be represented as the specific output power point that allows the engine's operating efficiency to reach a local or global maximum value under the dual constraints of the current gas state and the current maximum available power.

[0074] In this embodiment, the efficiency model can be a three-dimensional efficiency map. Specifically, the efficiency model can be a three-dimensional data table (i.e., an efficiency map) pre-calibrated through bench testing. The three dimensions of this data table are methane concentration, gas flow rate, and output power, and the corresponding output value is the operating efficiency of the internal combustion engine at that operating point.

[0075] In one possible and specific implementation, firstly, the real-time acquired methane concentration and gas flow rate values ​​can be used as fixed input conditions. Then, the search range for output power can be limited to between zero and the current maximum available power calculated in step S162. Finally, within the defined power range, the controller can calculate the efficiency values ​​corresponding to different output powers in the efficiency MAP using an interpolation algorithm (e.g., bilinear interpolation or cubic spline interpolation) and compare these efficiency values. The specific optimization algorithm can be to traverse all discrete points within the power range (if the data points are sufficiently dense), or to use a one-dimensional optimization algorithm such as the golden section method to find the output power point that maximizes the efficiency value.

[0076] Step S16464: Set the power value corresponding to the optimal efficiency operating point as the optimal output power value.

[0077] This implementation method introduces a pre-built efficiency model based on real-time gas parameter queries. Under conditions where biogas power is insufficient, it can accurately locate and lock the most efficient operating point of the internal combustion engine within a specific gas state and the range of currently available power. This ensures that the internal combustion engine always operates in the optimal efficiency range, significantly improving the instantaneous conversion efficiency of biogas energy. While ensuring a stable supply of compressed air, it maximizes the refinement of energy utilization and the economic efficiency of system operation.

[0078] This embodiment provides an energy-self-sufficient compressed air supply system, including: A biogas supply unit is used to collect and purify biogas generated by a wastewater treatment facility and output the state parameters of the biogas, including at least the gas flow rate and methane concentration.

[0079] In this embodiment, the biogas supply unit may include: The collection and purification module may comprise a series of devices connected sequentially along the airflow direction. Specifically, firstly, the generated raw biogas is collected by a flexible gas-film collection hood (e.g., using PVDF composite membrane material) covering the aeration tank or digester. The collected biogas first enters a gas-liquid separator (e.g., a cyclone separator) to remove carried liquid water mist and particulate impurities with a particle size greater than 10 micrometers. Then, the biogas enters a deep drying tower (which may be filled with 3A or 13X type molecular sieve adsorbent) to lower the biogas dew point to below -40°C, preventing subsequent pipelines from freezing. Finally, the biogas flows through a desulfurization tower (which may be filled with activated carbon impregnated with iron oxide or iron oxide desulfurizing agent) to reduce the hydrogen sulfide concentration to below the equipment safety threshold (e.g., below 20 ppm).

[0080] The status parameter output module enables real-time measurement and signal transmission of purified gas parameters. Specifically, a flow metering device (e.g., a vortex flow meter or a thermal mass flow meter) can be installed on the outlet pipe of the purification unit to detect the gas flow rate, and an online gas analyzer (e.g., a methane concentration analyzer based on the non-dispersive infrared (NDIR) principle) can be installed to detect the methane concentration.

[0081] The drive module includes an internal combustion engine driven by biogas, an electric motor driven by the power grid, and a power coupling mechanism. The output shafts of the internal combustion engine and the electric motor are connected to the input shaft of the compressor unit through the power coupling mechanism to jointly drive the compressor unit to operate. In this embodiment, the driving module may include: The power source may include a biogas internal combustion engine (e.g., a spark-ignition or compression-ignition gas engine with an intake system equipped with an air-fuel ratio controller) and an electric motor driven by the power grid (e.g., a three-phase asynchronous motor or a permanent magnet synchronous motor).

[0082] A dynamic coupling mechanism can specifically be: A hydraulic coupling can adjust the fluid filling rate in the working chamber through an electro-hydraulic actuator, thereby achieving stepless torque transmission from the driving end (pump wheel) to the driven end (turbine).

[0083] The controller is connected to the biogas supply circuit and the drive module respectively, and is used in the above-mentioned control method for energy self-sufficient compressed air supply.

[0084] In some embodiments, the biogas supply unit comprises the following components connected sequentially along the gas flow direction: A gas-liquid separator is used to remove liquid water and large particulate impurities from the biogas.

[0085] In this embodiment, the gas-liquid separator can be a cyclone separator. This device uses a tangential air inlet to generate high-speed rotation of the biogas within a cylindrical body. Centrifugal force throws denser liquid water mist and solid particles larger than 10 micrometers towards the cylinder wall, causing them to slide down and collect in a conical collection hopper at the bottom, thus achieving gas-liquid separation. The separated gas is discharged from the exhaust pipe at the top center. This stage primarily removes mechanical moisture and suspended impurities entrained in the biogas.

[0086] A drying tower is used to lower the dew point of the biogas.

[0087] In this embodiment, the drying tower can be a fixed-bed adsorption tower filled with solid adsorbent.

[0088] Desulfurization tower, used to remove hydrogen sulfide from the biogas; The power coupling mechanism is a hydraulic coupling.

[0089] In this embodiment, the hydraulic coupling may include a pump impeller connected to the output shafts of the electric motor and the internal combustion engine, and a turbine connected to the input shaft of the compressor unit. A gap exists between the two impellers, forming an annular working chamber. The working chamber may be filled with a mineral oil-based or synthetic transmission fluid. When the pump impeller is driven to rotate, the blades accelerate the working fluid, converting mechanical energy into liquid kinetic energy. The high-speed liquid impacts the turbine blades, thereby driving the turbine to rotate and converting the liquid kinetic energy back into mechanical energy for output. The power transmission process is completed through the working fluid medium and is not a rigid connection.

[0090] In this embodiment, a guide tube can be provided around the working chamber of the hydraulic coupling. The insertion depth of the guide tube into the working chamber can be controlled by an electro-hydraulic actuator (e.g., a linear displacement mechanism driven by a stepper motor or servo motor), thereby changing the fluid filling rate within the working chamber. The deeper the insertion, the greater the discharge flow, the lower the fluid filling rate, and the smaller the transmitted torque; conversely, the deeper the insertion, the greater the transmitted torque. By precisely adjusting the position of the guide tube through controller output commands (e.g., a 4-20mA signal), stepless adjustment of the transmitted torque can be achieved, thereby dynamically distributing the output power ratio between the internal combustion engine and the electric motor.

[0091] According to an embodiment of the present invention, an electronic device is provided; please refer to... Figure 3 The electronic device in this embodiment may include one or more of the following components: a processor, a network interface, memory, non-volatile memory, and one or more application programs, wherein the one or more application programs may be stored in non-volatile memory and configured to be executed by one or more processors, and the one or more programs are configured to perform the methods as described in the foregoing method embodiments.

[0092] According to embodiments of the present invention, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a computer, causes the computer to perform the method described in any of the above embodiments.

[0093] According to embodiments of the present invention, a computer program product comprising instructions is also provided, which, when executed by a computer, cause the computer to perform a method in any of the above embodiments.

[0094] As is known from common technical knowledge, this invention can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not the only ones. All modifications within the scope of this invention or equivalent to the scope of this invention are included in this invention.

[0095] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0096] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0097] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0098] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0099] 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 it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A control method for an energy self-sufficient compressed air supply, characterized in that, The method is executed by a controller and comprises: real-time acquisition of a state parameter of biogas generated by a sewage treatment facility; wherein the state parameter comprises at least gas flow and methane concentration; determination of whether a preset internal combustion engine starting condition is met based on the state parameter; when the internal combustion engine starting condition is met, generating a power distribution control instruction and sending it to a preset power coupling mechanism; wherein the power distribution control instruction is used to control the operating state of the preset power coupling mechanism to dynamically adjust the power output proportion of the biogas-driven internal combustion engine and the grid-driven electric motor to the compressor unit; wherein the power coupling mechanism is a transmission device configured between the internal combustion engine, the electric motor and the input shaft of the compressor unit, used to realize flexible coupling and stepless adjustment of the power output of the internal combustion engine and the electric motor.

2. The control method according to claim 1, characterized by, The step of real-time acquisition of a state parameter of biogas generated by a sewage treatment facility comprises: acquiring raw data obtained by real-time monitoring of biogas by a preset sensing device; performing validity verification on the raw data, and taking the data passing the verification as the state parameter.

3. The control method according to claim 2, characterized by, The step of determining whether a preset internal combustion engine starting condition is met based on the state parameter comprises: comparing the gas flow with a preset first flow threshold value, and comparing the methane concentration with a preset first concentration threshold value; if the gas flow continuously exceeds the first flow threshold value, and the methane concentration continuously exceeds the first concentration threshold value, and both reach a preset stable time length, it is determined that the internal combustion engine starting condition is met.

4. The control method according to claim 1, characterized by, The step of generating a power distribution control instruction and sending it to a preset power coupling mechanism when the internal combustion engine starting condition is met comprises: calculating the current maximum available power of the internal combustion engine according to the gas flow and methane concentration; determining a first target output power of the internal combustion engine and a second target output power of the electric motor based on the current maximum available power and the real-time power demand of the compressor unit; wherein the first target output power is configured to represent the output power expected to be assumed by the internal combustion engine under the current biogas state, and the second target output power is configured to represent the output power to be assumed by the electric motor to make up the difference between the first target output power and the real-time power demand; generating a control instruction for adjusting the operating state of the power coupling mechanism according to the first target output power and the second target output power.

5. The control method according to claim 4, characterized by The step of determining a first target output power of the internal combustion engine and a second target output power of the electric motor based on the current maximum available power and the real-time power demand of the compressor unit comprises: comparing the current maximum available power with the real-time power demand; when the current maximum available power is greater than or equal to the real-time power demand, setting the first target output power as the real-time power demand and setting the second target output power as zero; When the current maximum available power is less than the real-time power demand, a preset efficiency optimization algorithm is executed to determine an optimal output power value of the internal combustion engine within the range of the current maximum available power, and the optimal output power value is set as the first target output power, and a difference between the real-time power demand and the first target output power is set as the second target output power; wherein the efficiency optimization algorithm is configured to determine the optimal output power value by taking the highest comprehensive operation efficiency of the internal combustion engine under the current biogas state as a target.

6. The control method according to claim 5, characterized by The step of, when the current maximum available power is less than the real-time power demand, executing a preset efficiency optimization algorithm to determine an optimal output power value of the internal combustion engine within the range of the current maximum available power, and setting the optimal output power value as the first target output power, and setting a difference between the real-time power demand and the first target output power as the second target output power, comprises: determining, based on the methane concentration and the gas flow, an optimal efficiency working point of the internal combustion engine within the range of the current maximum available power by querying a pre-established efficiency model reflecting the corresponding relationship between the efficiency and the output power of the internal combustion engine under different gas states; setting a power value corresponding to the optimal efficiency working point as the optimal output power value.

7. An energy self-sufficient compressed air supply system, characterized in that Comprise: a biogas supply unit configured to collect and purify biogas generated by a sewage treatment facility, and output state parameters of the biogas, the state parameters at least including a gas flow and a methane concentration; a drive module comprising an internal combustion engine driven by biogas, an electric motor driven by an electric power grid, and a power coupling mechanism, wherein output shafts of the internal combustion engine and the electric motor are connected to an input shaft of a compressor unit through the power coupling mechanism to jointly drive the compressor unit to operate; a controller connected to the biogas supply circuit and the drive module, respectively, and configured to execute any one of the control methods for energy self-sufficient compressed air supply according to claims 1-6.

8. The control method according to claim 7, characterized by, The biogas supply unit comprises, in sequence along the gas flow direction: a gas-liquid separator configured to remove liquid water and large-particle impurities in the biogas; a drying tower configured to reduce the dew point of the biogas; a desulfurization tower configured to remove hydrogen sulfide components in the biogas; the power coupling mechanism is a hydraulic coupling.

9. An electronic device, comprising: Comprise: a memory, and one or more processors in communication connection with the memory; the memory stores instructions executable by the one or more processors, and the instructions are executed by the one or more processors to cause the one or more processors to implement the method according to any one of claims 1-6.

10. A computer-readable storage medium, characterized in that, The readable storage medium stores a computer program, and the computer program is executed by a processor to implement the method according to any one of claims 1-6.

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