System for automatically monitoring greenhouse gas emission of sewage treatment plant

Abstract

The embodiment of the utility model discloses a system for automatically monitoring greenhouse gas emission of a sewage treatment plant, which comprises a gas collection unit, at least one gas supply unit, an analysis unit and a flushing unit, and each gas collection unit is connected with a first outlet of the flushing unit and one end of the gas supply unit through a three-way valve; a second outlet of the flushing unit is connected with one end of the gas supply unit, the other end of the gas supply unit is connected with the analysis unit, and the gas collection unit and the gas supply unit are both provided with flushing outlets. According to the embodiment, alternate operation of the flushing unit and the gas collecting unit can be achieved, and continuous greenhouse gas monitoring activities are established and are not affected by seasons.

Description

Technical Field

[0001] The utility model relates to the field of gas monitoring devices, in particular to a system for automatically monitoring greenhouse gas emissions from sewage treatment plants. Background Art

[0002] Most current greenhouse gas inventories underestimate emissions. Key limitations are the scarcity of representative continuous monitoring campaigns and a limited understanding of the mechanisms of N2O formation during biological denitrification in wastewater treatment plants. Furthermore, non-CO2 greenhouse gas emission patterns from wastewater treatment plants exhibit strong seasonal variations, which are difficult to capture with existing intermittent monitoring campaigns. Therefore, establishing a continuous greenhouse gas monitoring campaign is a key step in accurately estimating representative emission factors, supporting more precise greenhouse gas emissions assessments. Utility Model Content

[0003] The embodiment of the utility model discloses a system for continuously monitoring greenhouse gas emissions from a sewage treatment plant, which is used to establish a continuous greenhouse gas monitoring activity.

[0004] An embodiment of the present utility model provides a system for automatically monitoring greenhouse gas emissions from a sewage treatment plant, comprising an air collecting unit, at least one air supply unit, an analysis unit and a flushing unit, wherein each of the air collecting units is connected to the first outlet of the flushing unit and one end of the air supply unit via a three-way valve, the second outlet of the flushing unit is connected to one end of the air supply unit, and the other end of the air supply unit is connected to the analysis unit, and both the air collecting unit and the air supply unit are provided with a flushing outlet.

[0005] Furthermore, the flushing unit includes a flushing pump and a first gas-liquid separator, and the outlet end of the first gas-liquid separator is connected to the inlet end of the flushing pump.

[0006] Furthermore, the air supply unit includes an air pump and a second gas-liquid separator, and the inlet end of the air pump is connected to the outlet end of the second gas-liquid separator.

[0007] Furthermore, the air delivery unit also includes a gas dryer and a precision filter. The inlet end of the gas dryer is connected to the outlet end of the second gas-liquid separator, the outlet end of the gas dryer is connected to the inlet end of the precision filter, and the outlet end of the precision filter is connected to the inlet end of the air pump, so as to prevent the dried particles in the sample gas from entering the analysis unit through the air pump.

[0008] Furthermore, the air supply unit further includes a moisture sensor, which is arranged between the gas dryer and the air pump.

[0009] Furthermore, the air supply unit further includes a pressure relief valve, which is arranged at the outlet end of the air pump.

[0010] Furthermore, the air supply unit also includes a protective filter, the inlet end of the protective filter is connected to the inlet end of the pressure relief valve, and the protective filter is used to increase its flow resistance when it comes into contact with moisture to prevent moisture from passing through.

[0011] Furthermore, the air supply unit further includes a flow controller, the inlet end of the flow controller is connected to the outlet end of the protection filter, and the outlet end of the flow controller is connected to the analysis unit.

[0012] Furthermore, the air collecting unit includes a floating hood, which includes an air pipe, an air collecting hood and a float arranged on the side of the air collecting hood. The air pipe is arranged above the air collecting hood, one end of the air pipe is connected to the air collecting hood, and the other end of the air pipe is an exhaust port. A side interface is provided in the middle of the air pipe, and the side interface is connected to the air supply unit and the flushing unit.

[0013] Furthermore, a bend is provided at the other end of the gas pipe, and the bend is used to direct the gas collecting port toward the liquid surface.

[0014] It can be seen from the technical solution that the embodiment provided by the utility model has the following advantages:

[0015] This embodiment can realize that when the gas collection unit is in operation, the flushing unit stops operating, and the gas collected by the gas collection unit is transported to the analysis unit through the gas delivery unit for analysis. When the gas collection unit stops operating, the flushing unit starts. On the one hand, it ensures that there is continuous airflow in the gas delivery unit during the measurement interval, and avoids the suspension of airflow causing condensed water to accumulate in certain positions of the gas delivery unit, and then freeze, affecting subsequent monitoring activities. On the other hand, the flushing unit needs to ensure that the gas collection unit and the gas delivery unit are flushed during the measurement interval, and the residual gas and water vapor in the gas collection unit and the gas delivery unit and their connecting channels are cleared to ensure the accuracy of the measurement so as to continuously update the gas sample. The flushing unit and the gas collection unit operate alternately to achieve the establishment of continuous greenhouse gas monitoring activities that are not affected by the seasons. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1This is a schematic structural diagram of a system for automatically monitoring greenhouse gas emissions from a sewage treatment plant provided in an embodiment of the present utility model, comprising a gas collection unit;

[0018] Figure 2 This is a schematic structural diagram of a system for automatically monitoring greenhouse gas emissions from a sewage treatment plant provided in an embodiment of the present utility model, comprising two gas collection units;

[0019] Figure 3 A schematic structural diagram of a floating cover in a system for automatically monitoring greenhouse gas emissions from a sewage treatment plant provided in an embodiment of the present invention;

[0020] Reference numerals:

[0021] 1. Gas collection unit; 2. Flushing unit; 3. Gas supply unit; 4. Analysis unit; 5. Control unit; 6. Solenoid three-way valve; 61. First solenoid three-way valve; 62. Second solenoid three-way valve; 10. Floating cover; 101. Gas cover; 102. Gas pipe; 103. Side interface; 104. Elbow; 105. Floating body; 106. Rope fixing hole; 11. First floating cover; 12. Second floating cover; 21. Flushing pump; 22. First gas-liquid separator; 221. First condensation pump; 31. Second gas-liquid separator; 311. Second condensation pump; 32. Gas dryer; 321. Third condensation pump; 33. Precision filter; 34. Moisture sensor; 35. Gas pump; 36. Protection filter; 37. Flow controller; 38. Pressure relief valve; 41. Greenhouse gas analyzer; 51. Electrical control cabinet; 52. Computer. DETAILED DESCRIPTION

[0022] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0023] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of this utility model, unless otherwise specified, "plurality" means two or more.

[0024] In the description of this utility model, it should be noted that, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediary, or internal communication between two components. Those skilled in the art will understand the specific meanings of these terms in this utility model based on specific circumstances.

[0025] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0026] It should be understood that although the steps in the flowcharts of the accompanying drawings are shown in sequence as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some of the steps in the flowcharts of the accompanying drawings may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and their execution order is not necessarily sequential, but can be executed in turn or alternately with other steps or at least a portion of the sub-steps or stages of other steps.

[0027] The embodiment of the utility model discloses a system for automatically monitoring greenhouse gas emissions from a sewage treatment plant.

[0028] See also Figure 1 In an embodiment of the present invention, a system for automatically monitoring greenhouse gas emissions from a sewage treatment plant is provided, and one embodiment includes:

[0029] It includes: a gas collecting unit 1, at least one gas supply unit 3, an analysis unit 4 and a flushing unit 2. The flushing unit 2 includes a first outlet and a second outlet. Each gas collecting unit 1 is connected to the first outlet of the flushing unit 2 and one end of the gas supply unit 3 through a three-way valve. The second outlet of the flushing unit 2 is connected to one end of the gas supply unit 3, and the other end of the gas supply unit 3 is connected to the analysis unit 4. The gas collecting unit 1 and the gas supply unit 3 are both provided with a flushing outlet.

[0030] It is understandable that, in specific implementation, when the gas collecting unit 1 is in operation, the flushing unit 2 stops operating, and the gas collected by the gas collecting unit 1 is transported to the analysis unit 4 for analysis through the gas delivery unit 3. When the gas collecting unit 1 stops operating, the flushing unit 2 starts. On the one hand, it ensures that there is continuous airflow in the gas delivery unit 3 during the measurement interval, and avoids the suspension of airflow causing condensed water to accumulate in certain positions of the gas delivery unit 3, which then freezes and affects subsequent monitoring activities. On the other hand, the flushing unit 2 needs to ensure that the gas collecting unit 1 and the gas delivery unit 3 are flushed during the measurement interval, and the residual gas and water vapor in the gas collecting unit 1 and the gas delivery unit 3 and their connecting channels are cleared to ensure the accuracy of the measurement so that the gas samples can be continuously updated. The flushing unit 2 and the gas collecting unit 1 operate alternately to establish continuous greenhouse gas monitoring activities, and continuous monitoring can be achieved even in cold environments.

[0031] In one specific embodiment, the flushing unit 2 includes a flushing pump 21, a first gas-liquid separator 22, and a first condensation pump 221 connected to the first gas-liquid separator 22, located before the gas inlet of the flushing pump 21. It is understood that, in practice, the gas input by the flushing pump 21 does not contain the component to be measured, but may contain water and other particles. The gas-liquid separator and a condensation pump connected to the gas-liquid separator are provided to protect the flushing pump 21 from contamination by water and particles. It is understood that the first gas-liquid separator 22 achieves separation by utilizing the differences in physical properties of different substances. When a mixed gas containing water and particles enters the gas-liquid separator, the different densities of the gas, liquid, and particles alter the gas flow path under specific structural designs, allowing the heavier liquid and particles to separate from the gas under the effects of gravity, centrifugal force, and other factors. During the gas-liquid separation process, some water vapor may condense into liquid water. The function of the first condensation pump 221 is to promptly discharge this condensed water from the system to prevent it from re-incorporating into the gas or impacting subsequent equipment. In some specific embodiments, the first gas-liquid separator 22 is a cyclone gas-liquid separator that generates centrifugal force through high-speed rotating airflow, throwing liquid and particles toward the wall, and then sliding along the wall to the collection area, while the gas flows out from the center.

[0032] It is understood that the flushing pump 21 is required to ensure that all pipelines are flushed during the measurement interval so as to continuously update the gas sample, speed up the measurement, reduce the freezing problem in winter, and prevent condensed water from accumulating in the gas pipeline.

[0033] In a more specific embodiment, the flushing gas is air, which contains very low levels of wastewater and exhaust components, thus not affecting the monitoring results. In other more specific embodiments, the flushing gas is free of contaminants that could interfere with monitoring, and nitrogen is used as the flushing gas. Nitrogen is an inert gas that is relatively stable and does not readily react with the monitored gas, effectively removing the sample gas from the system.

[0034] In a more specific embodiment, when the air supply distance of the air supply unit 3 is greater than a certain value, specifically greater than 150 meters, it is necessary to set multiple flushing units 2 on the air supply unit 3 to ensure that the gas flow rate per unit time in the air supply unit 3 is maintained at a stable value, to prevent the pressure difference between different positions in the air supply unit 3 from being large, and to avoid insufficient flow in some pipelines due to excessive pressure difference, thereby failing to ensure the normal operation of the system. During specific implementation, it is necessary to ensure that all pipelines can provide a gas flow rate of at least 1 liter / minute, regardless of the pressure drop in the pipeline. In addition, to avoid excessive gas pressure, a T-shaped branch with a pressure relief valve can be installed to ensure that excess sample gas is diverted and discharged.

[0035] It should be noted that during the monitoring process, in addition to condensation, foam may also form on the aeration tank. Furthermore, if the floating cover 10 sinks, liquid may be drawn into the equipment. For these reasons, the sample gas undergoes multiple stages of pretreatment on the air delivery unit 3 before entering the analysis unit 4 to prevent the formation of condensation in the analysis unit 4.

[0036] In a more specific embodiment, the gas supply unit 3 includes at least one gas pump 35 . The gas pump 35 provides a constant flow of sample gas to the analysis unit 4 . The gas pump 35 provides a flow of 1 liter / minute to the analysis unit 4 .

[0037] In a more specific embodiment, a second gas-liquid separator 31 and a second condensation pump 311 connected to the second gas-liquid separator 31 are provided before the air inlet of the air pump 35. It is understood that, during implementation, the gas input by the air pump 35 may also contain water and particles. The second gas-liquid separator 31 and the second condensation pump 311 connected to the second gas-liquid separator 31 are provided to protect the air pump 35 from contamination by water and particles. It is understood that the second gas-liquid separator 31 utilizes the differences in physical properties of different substances to achieve separation. When a mixed gas containing water and particles enters the gas-liquid separator, the different densities of the gas, liquid, and particles alter the gas flow path under specific structural designs, allowing the heavier liquid and particles to separate from the gas under the effects of gravity, centrifugal force, and other factors. During the gas-liquid separation process, some water vapor may condense into liquid water. The function of the second condensation pump 311 is to promptly remove this condensed water from the system to prevent it from re-incorporating into the gas or impacting subsequent equipment. In some specific embodiments, the second gas-liquid separator 31 is a cyclone-type gas-liquid separator that generates centrifugal force through high-speed rotating airflow, flinging liquid and particles toward the wall of the device, which then slides down the wall to a collection area, while the gas flows out from the center. When the air supply distance of the air supply unit 3 is greater than a certain value, specifically greater than 150 meters, it is necessary to set up multiple air pumps 35 on the air supply unit 3 to ensure that the gas flow rate per unit time in the air supply unit 3 remains at a stable value, prevent the pressure difference between different positions in the air supply unit 3 from being large, and avoid insufficient flow in some pipelines due to excessive pressure difference, thereby preventing the normal operation of the system; and ensure the measurement frequency so that the system allows one measurement per minute, even if the pipeline length is greater than 150 meters.

[0038] In a more specific embodiment, the gas delivery unit 3 also includes a gas dryer 32, which is arranged between the air pump 35 and the gas-liquid separator to further remove moisture from the sample gas to prevent moisture from entering the analysis unit 4 and affecting the safe operation of the system.

[0039] In a more specific embodiment, the gas dryer 32 is connected to a condensation pump, and a third condensation pump 321 is provided to continuously remove moisture generated during the drying process, ensuring that the sample gas enters the analysis device free of condensate. It will be appreciated that, in a specific implementation, the gas dryer 32 and the third condensation pump 321 can ensure that the relative humidity of the sample gas is less than 100%, thereby preventing condensation in the analysis unit 4.

[0040] In a more specific embodiment, the air delivery unit 3 also includes a precision filter 33, which is arranged between the second gas-liquid separator 31 and the air pump 35, and the precision filter 33 is arranged after the gas dryer 32. The precision filter 33 is used to filter dust and particles generated after the sample gas is dried to prevent dust and particles from entering the analysis unit 4.

[0041] In a more specific embodiment, the air delivery unit 3 also includes a moisture sensor 34, which is arranged between the gas dryer 32 and the air pump 35. The moisture sensor 34 is used to monitor whether moisture is detected after the gas is dried. If moisture is detected, the air pump 35 will be shut down to prevent water from entering the air pump 35 or further entering the analysis unit 4, affecting the safe operation of the system.

[0042] In a more specific embodiment, the air supply unit 3 includes at least one pressure relief valve 38 , which discharges part of the gas to restore the gas pressure in the air supply unit 3 to a normal state when the gas pressure in the air supply unit 3 is too high.

[0043] In a more specific embodiment, the flushing outlet of the gas collecting unit 1 is a pressure relief valve 38 .

[0044] In a more specific embodiment, the pressure relief valve 38 is disposed behind the air pump 35 to achieve timely pressure relief.

[0045] In a more specific embodiment, the gas supply unit 3 includes a protective filter 36, which is positioned before the analysis unit 4. It will be appreciated that the protective filter 36 is a gas-permeable microfiltration device that serves as a final barrier to prevent water from entering the analyzer. Upon contact with water, the filter significantly increases its flow resistance, preventing water from passing through. In some specific embodiments, the protective filter 36 is a polymer microporous membrane filter, a polytetrafluoroethylene (PTFE) hydrophobic filter, an activated carbon fiber filter, or a membrane filter dryer.

[0046] In a more specific embodiment, the protection filter 36 is disposed after the pressure relief valve 38 , which can release part of the gas when the pressure is too high to prevent water from penetrating the filter due to excessive pressure, thereby ensuring safe operation of the system.

[0047] In a more specific embodiment, the gas supply unit 3 further includes a flow controller 37, which is disposed between the protective filter 36 and the analysis unit 4. The flow controller 37 is used to monitor and control the flow rate of the sample gas at a certain value. It is understandable that different analytical instruments generally require specific flow conditions to accurately perform measurements and analyses. The flow controller 37 can ensure that the flow rate of the sample gas entering the analysis unit 4 is stable within a suitable range. For example, some chromatographs require a specific carrier gas flow rate to achieve a good separation effect; spectrometers may also have strict requirements on the flow rate of the sample gas to ensure that the interaction between light and the sample is stable, thereby obtaining accurate analysis results; if the flow rate is unstable, it may cause fluctuations in the analysis results and reduce the accuracy and reliability of the measurement. The flow controller 37 can monitor and control the sample gas flow rate (1 liter / minute).

[0048] In a more specific embodiment, the analysis unit 4 is a GHG analyzer, which is an analyzer for measuring greenhouse gases and can simultaneously monitor CH4 and N2O. The measurement range is: CH4 is 0 to 1000 ppm in the exhaust gas discharged from the aeration reactor and 0 to 2000 ppm in the exhaust gas discharged from sludge treatment; N2O emissions in wastewater treatment are generally in the range of 0 to 3000 ppm.

[0049] In a more specific embodiment, the gas collection unit 1 includes a floating cover 10, such as Figure 3 As shown, the air collecting unit 1 includes a floating hood 10, and the floating hood 10 includes an air pipe 102, an air collecting hood 101 and a float 105 arranged on the side of the air collecting hood 101. The air pipe 102 is arranged above the air collecting hood 101, and one end of the air pipe 102 is connected to the air collecting hood 101. The other end of the air pipe 102 is an exhaust port. A side interface 103 is provided in the middle of the air pipe 102, and the side interface 103 is connected to the air supply unit 3 and the flushing unit 2.

[0050] In a more specific embodiment, the side port 103 is arranged on one end of the air pipe 102 close to the gas collecting hood 101. It can be understood that shortening the distance between the side port 103 and the gas collecting hood 101 can achieve more efficient transportation of waste gas samples and stay away from the exhaust port of the air pipe 102 to avoid inhaling other mixed gases from the exhaust port to affect the analysis results.

[0051] It can be understood that, in specific implementation, the gas collecting hood 101 is used to collect representative exhaust gas samples on the surface of the aeration tank, and is a cavity for temporarily storing sample gas; the float 105 is a closed structure that allows the floating hood 10 to float stably on the liquid surface; the air pipe 102 is used to discharge the sample gas in the gas collecting hood 101, and transport the sample gas to the air supply unit 3 through the side interface 103; an exhaust port is provided on the upper part of the air pipe 102 to ensure that the gas collecting hood 101 collects the sample gas without affecting the continuous discharge of the exhaust gas from the liquid surface below the gas collecting hood 101; in addition, the flushing unit 2 and the air supply unit 3 are connected to the side interface 103 through a pipeline, and part of the flushing gas of the flushing unit 2 enters the air pipe 102 from the side interface 103, and is further discharged from the outlet at the top of the air pipe 102 under the drive of the gas flow in the air pipe 102, thereby cleaning the sample gas delivery pipeline between the side interface 103 and the air supply unit 3, removing the residual sample gas and water vapor in the pipeline, and ensuring the accuracy of the next gas measurement.

[0052] In a more specific embodiment, the side port is connected to the air supply unit 3 via a sampling hose.

[0053] In a more specific embodiment, the gas collecting hood 101 is made of a lightweight material such as polyethylene, and its frame is made of a sealed pipe (diameter DN50).

[0054] In a more specific embodiment, the enclosed space below the gas hood 101 and the liquid surface prevents exhaust gases from dispersing, concentrating them within the hood. When exhaust gases from the aeration tank are released from the water surface, they are captured by the hood 101. The enclosed space below the hood prevents exhaust gases from dispersing, concentrating them within the hood. The hood 101 covers one square meter of the pool surface, effectively collecting exhaust gases released from the water surface.

[0055] In a more specific embodiment, a bend 104 facing the liquid surface is provided at the top of the air pipe 102 , specifically an open 180° bend 104 , which is connected to the air pipe 102 through a joint, thereby preventing rainwater or splashing objects from entering the air pipe 102 .

[0056] In a more specific embodiment, in order to prevent rainwater and splashing objects from entering through the opening of the elbow 104, the cover surface of the air collecting hood 101 is designed to be inclined.

[0057] It can be understood that the floating cover 10 of this embodiment can collect exhaust gas on the surface of the aeration tank and is not affected by rain or splashes. Therefore, the monitoring system using the floating cover 10 of this embodiment can be used in both sewage treatment plants with roofs and sewage treatment plants without roofs.

[0058] In a more specific embodiment, a spare interface is provided on the side of the air pipe 102, which is located on the side of the side interface 103. The structure of the spare interface is the same as that of the side interface 103, so that it can be used for system upgrades or future equipment additions, thereby facilitating expansion without major modifications to the system.

[0059] In a more specific embodiment, rope fixing holes 106 are provided at the four corners of the floating cover. One end of a rope is connected to the rope fixing hole 106, and the other end is connected to the guardrail at the edge of the aeration tank, thereby securing the floating cover 10 to the guardrail at the edge of the aeration tank. It will be understood that the ropes ensure that the floating cover 10 does not drift away from the predetermined position due to water currents or wind, and at the same time prevent the floating cover from contacting the rough tank wall.

[0060] In a more specific embodiment, when measurements are taken in a reactor with no aeration, low aeration, or intermittent aeration, a ceramic aerator may be installed below the gas collecting hood 101 to ensure that the gas in the aeration tank reactor is properly stirred and mixed even in the case of low or intermittent aeration, thereby reducing uneven gas concentration and ensuring that gas exposure is minimized.

[0061] It can be understood that the gas collecting hood 101 collects the waste gas discharged from the liquid surface of the aeration tank, and can concentrate the waste gas in the gas collecting hood 101, reduce the mixing of other gases, minimize the volume of enclosed gas, and improve measurement efficiency. At the same time, the gas collecting hood 101 is connected to the air pipe 102, which does not affect the discharge of waste gas and prevents rainwater or splashing objects from entering the air pipe 102 and the gas collecting hood 101, creating optimal mixing and sampling conditions.

[0062] In a more specific embodiment, when multiple sampling points need to be sampled, multiple gas collecting units 1 are included, and each gas collecting unit 1 is equipped with an independent three-way valve.

[0063] In a more specific embodiment, the three-way valve is a solenoid three-way valve 6 (two inlets, one outlet). This solenoid three-way valve 6 is controlled by a PLC to alternately operate the flushing unit 2 and the gas collection unit 1. In this continuous monitoring system, the flushing and measurement processes are switched. Typically, a single measurement takes approximately one minute: 30 seconds of flushing followed by 30 seconds of measurement. The operating principle is as follows:

[0064] Washout phase (30 seconds):

[0065] The three-way solenoid valve directs the airflow to the flushing pipeline and turns on the flushing mode;

[0066] Compressed air enters the pipeline through the flushing pump 21 to remove residual gas and water vapor therein, thereby ensuring accuracy during measurement.

[0067] During this phase, the measuring channel is closed, protecting the analysis unit 4 from the flushing gas.

[0068] Measurement phase (30 seconds):

[0069] The three-way solenoid valve switches to measurement mode, closes the flushing channel, and opens the measurement channel.

[0070] The monitored gas flows into the analysis unit 4 to detect the concentration of greenhouse gases (such as N2O, CH4, etc.);

[0071] During this phase, the flushing channel remains closed to ensure that the gas enters the analysis unit 4 directly from the sampling point.

[0072] In a more specific embodiment, the control unit 5 comprises an electrical control cabinet 51 and a computer 52 electrically connected to the control cabinet. Computer 52 serves as an interface for parameter settings and remote access. It should be configured to automatically restart and log in after a power outage to quickly restore remote access (a virtual machine can also be used as an alternative). The electrical control cabinet 51 includes a programmable logic controller (PLC), which converts analog signals into digital signals, stores measured values ​​and system parameters on a microSD card, and generates alarms and initiates emergency shutdowns. Through the automated control of the control unit 5, reliable monitoring and sampling of selected points is achieved, with sampling intervals less than 15 minutes.

[0073] In some more specific embodiments, the PLC may be built into the electrical control cabinet 51. It is understood that the sample gas pump 35, the flushing pump 21, and the electromagnetic three-way valve 6 are all electrically connected to the electrical control cabinet 51, and the opening and closing of the sample gas pump 35, the flushing pump 21, and the electromagnetic three-way valve 6 are controlled by the PLC.

[0074] Automatic monitoring by the control unit 5 usually requires setting the following parameters:

[0075] (1) Test and set the sample flushing time, which is the delay between the solenoid three-way valve switching to the new position and the recording of the signal output. This delay can be determined by manually switching between two sampling points with significantly different gas compositions and recording the time required for the signal to reach a representative value. This is usually done at the sampling point and includes the flushing of the gas pre-treatment. It can usually be set to 30 seconds.

[0076] (2) Determine the total opening time of the electromagnetic three-way valve (i.e., sample flushing delay time + measurement time) required for a single measurement. This is usually set to 1 minute.

[0077] (3) Name all required solenoid three-way valve 6 valve positions and switch them to automatic mode.

[0078] (4) Set the sample gas flow rate controlled by the flow controller 37 and set the minimum required value. Usually it is 1-0.5 liters / minute.

[0079] The working principle of the automatic control unit 5 is:

[0080] Sequential sampling: Only one electromagnetic three-way valve 6 of a sampling point will be open at a time, ensuring that the gas at each sampling point enters the system for analysis independently, and no gas mixing occurs between different sampling points.

[0081] Parallel control: Although each sampling is only for one point, the PLC can simultaneously control the switch status of multiple electromagnetic three-way valves, thereby ensuring that the system can quickly switch sampling points and maximize sampling efficiency.

[0082] Valve switching process:

[0083] Pipeline flushing stage: When the PLC starts a sampling point, the electromagnetic three-way valve 6 of other sampling points is first closed, and the flushing pump 21 is turned on to flush the pipeline of the sampling point with gas to prevent condensate or residual gas in the pipeline from affecting the sampling accuracy.

[0084] Sampling stage: After the flushing is completed, the PLC control system will open the electromagnetic three-way valve 6 corresponding to the sampling point, and introduce the exhaust gas at the sampling point into the gas analysis unit 4 to measure the gas composition.

[0085] Close the valve: After the sampling is completed, the PLC will close the electromagnetic three-way valve 6 of the sampling point and switch to the next sampling point, repeating the above flushing and sampling process.

[0086] In a more specific embodiment, the connecting channels between the gas collection unit 1, gas delivery unit 3, analysis unit 4, flushing unit 2, and control unit 5 are all pneumatic tubes, and the connecting channels between the components within each unit are also pneumatic tubes. Pneumatic tubes are used to connect the components of each unit, allowing sample gas to be transported from the side port 103 of the air pipe 102 of the floating cover 10 to the greenhouse gas analyzer 41. The pneumatic tubes serve as gas transmission channels between the components to achieve gas transmission. In some more specific embodiments, when the gas transmission distance does not exceed 150 meters, a polyurethane pneumatic tube with an inner diameter of 4 mm is used. In other more specific embodiments, when the gas transmission distance exceeds 150 meters, a polyurethane pneumatic tube with an inner diameter of 6 mm is used. It should be noted that in specific implementations, in areas where frost is expected, condensed water freezing may cause pipe blockage. A flushing unit 2 is installed to ensure continuous airflow in all pipes during measurement intervals to prevent pauses in airflow from causing condensed water to accumulate in certain locations and subsequently freeze.

[0087] In a more specific embodiment, a system for automatically monitoring greenhouse gas emissions from a wastewater treatment plant is disclosed. Figure 1As shown, it includes: a gas collecting unit 1, a gas supply unit 3, an analysis unit 4, a flushing unit 2 and a control unit 5, the gas collecting unit 1 includes a floating cover 10; the flushing unit 2 includes a flushing pump 21, a first gas-liquid separator 22 and a first condensation pump 221 connected to the first gas-liquid separator 22, and the input end of the flushing pump 21 is connected to the first gas-liquid separator 22; the gas supply unit 3 includes a second gas-liquid separator 31, a gas dryer 32, a precision filter 33, a moisture sensor 34, an air pump 35, a protection filter 36, a flow controller 37 and a second condensation pump 311 connected to the second gas-liquid separator 31, a gas dryer 32 connected to the gas dryer 32, The third condensation pump 321 is provided with a pressure relief valve 38 between the air pump 35 and the protective filter 36; the analysis unit 4 includes a greenhouse gas analyzer 41, the control unit 5 includes a computer and an electrical control cabinet 51, and the computer 52 is electrically connected to the electrical control cabinet 51; the first outlet of the floating cover 10 and the flushing pump 21 are connected to the floating cover 10 through the electromagnetic three-way valve 6, and the second outlet of the flushing pump 21 is connected to the air inlet end of the second gas-liquid separator 31; the greenhouse gas analyzer 41, the flushing unit 2, the air supply unit 3 and the three-way electromagnetic valve are all electrically connected to the electrical control cabinet 51. In this embodiment, the connection channel used to connect and realize gas transportation between various devices is a pneumatic tube.

[0088] In a more specific embodiment, it includes two air collecting units 1, namely a first air supply unit 3 and a second air supply unit 3. The first air supply unit 3 is a first floating cover 11, and the second air supply unit 3 is a second floating cover 12. The first floating cover 11 is connected to the first outlet of the flushing pump 21 and the input end of the first gas-liquid separator 22 through a first electromagnetic three-way valve 61, and the second floating cover 12 is connected to the first outlet of the flushing pump 21 and the input end of the first gas-liquid separator 22 through a second electromagnetic three-way valve 62.

[0089] The working principle of the gas measurement in this embodiment is:

[0090] Exhaust gas is first collected as a sample by a floating hood mounted on the surface of the aeration tank, covering approximately 1 square meter of the tank surface. After transmission, the sample gas first passes through a second gas-liquid separator 31 to remove moisture. A second condensate pump is installed after the second separator to discharge the separated condensate, ensuring the dryness of the sample gas. To further reduce humidity, the sample gas enters a gas dryer 32. A third condensate pump 321 continuously removes moisture generated during the drying process, ensuring that the sample gas enters the greenhouse gas analyzer 41 free of condensate. The dried sample gas passes through a precision filter 33 to remove any remaining particles and impurities. To prevent any liquid or particulate matter from entering the greenhouse gas analyzer 41, a protective filter 36 (a gas permeation microfiltration device) is also installed. Its microfiltration membrane retains any residual liquid. A pressure relief valve 38 prevents excessive pressure within the system, which could damage the filter or other equipment. The dried, filtered sample gas is delivered to the greenhouse gas analyzer 41 via an air pump 35. Before entering the analyzer 41, the sample gas passes through a flow controller 37 to adjust its flow rate, typically set at 1 liter / minute, to ensure a stable sample flow. The flow controller 37 also monitors and adjusts the sample gas flow to ensure measurement accuracy. A moisture sensor 34 continuously monitors the moisture content of the gas. If moisture is detected in the sample gas, the electrical control cabinet 51 immediately shuts down the air pump 35 to protect the analyzer 41 from liquid contamination.

[0091] The working principle of the flushing gas in this embodiment is as follows: flushing gas is sucked in from the outside through the flushing pump 21, and the flushing gas is pressed into the gas delivery unit 3 and the gas collection unit 1 through the outlet of the flushing pump 21. The flushing gas will flow through each pneumatic tube related to gas sampling to ensure that all pneumatic tubes and pipelines are flushed clean. After flowing through the entire system, the flushing gas is finally discharged through the pressure relief valve 38 or the elbow 104 of the air pipe 102 of the gas collection unit 1, and will not enter the greenhouse gas analyzer 41. The function of the pressure relief valve 38 is to ensure the orderly discharge of the flushing gas and prevent excessive air pressure from damaging the equipment. In this system, most of the flushed gas will be discharged from the system through the elbow 104 of the air pipe 102. The start-up of the flushing pump 21 is controlled by a programmable logic controller (PLC) and can automatically operate according to the set time interval.

[0092] The working principle of continuous monitoring in this embodiment is as follows:

[0093] When there is only one air supply unit 3, Figure 1As shown, the system only samples one sampling point. When the system is running, it takes one minute to measure one sampling point, including 30 seconds of flushing and 30 seconds of measurement. The measurement interval is 30 seconds of flushing time. During flushing, the analysis unit 4 is closed, the air supply unit 3 is blocked from the air collection unit 1, and the air supply unit 3 is connected to the first outlet of the flushing unit 2. The flushing gas is output from the first outlet of the flushing unit 2 into the air supply unit 3 to clear the residual sample gas and water vapor in the air supply unit 3, ensuring the accuracy of the measurement. At the same time, it ensures that the air supply unit 3 has continuous airflow in the cold environment to prevent condensed water from freezing in the air supply unit 3. Finally, the flushing gas of the air collection unit 1 is discharged from the pressure relief valve 38. At the same time, the air collection unit 1 is connected to the second outlet of the flushing unit 2. The flushing gas is output from the second outlet of the flushing unit 2 into the air collection unit 1 to clear the connection channel between the three-way valve and the air collection unit and the residual sample gas and water vapor in the air collection unit 1, ensuring the accuracy of the measurement. During measurement, analysis unit 4 is opened, gas supply unit 3 is connected to gas collection unit 1, gas supply unit 3 is disconnected from flushing unit 2, and gas collection unit 1 is disconnected from flushing unit 2. The sample gas collected by gas collection unit 1 is transported via gas supply unit 3 to analysis unit 4 for analysis and monitoring. This rinsing and measurement process is repeated continuously to achieve continuous monitoring of a single sampling point, even in cold environments.

[0094] When there are two air supply units 3, Figure 2 As shown, the system performs sampling at multiple sampling points. When the system is running, the sample gas at each sampling point is measured in turn. It also takes one minute to measure each sampling point in turn, including 30 seconds of flushing and 30 seconds of measurement.

[0095] First, measure the first sampling point: during flushing, the electrical control cabinet 51 controls the analysis unit 4 to close, the air supply unit 3 is blocked from the first air collecting unit 1 and the second unit, the air supply unit 3 is connected to the first outlet of the flushing unit 2, and the flushing gas is output from the first outlet of the flushing unit 2 into the air supply unit 3 to remove the residual sample gas and water vapor in the air supply unit 3 to ensure the accuracy of the measurement, and at the same time ensure that the air supply unit 3 has continuous airflow in the cold environment to prevent condensed water from freezing in the air supply unit 3. Finally, the flushing gas of the air collecting unit 1 is discharged from the pressure relief valve 38; while flushing, the electrical control cabinet 51 controls the first air collecting unit 1 to be connected to the second outlet of the flushing unit 2, the second air collecting unit 1 is blocked from the second outlet of the flushing unit 2, and the flushing gas is output from the second outlet of the flushing unit 2 into the air collecting unit 1 to remove the residual sample gas and water vapor in the first air collecting unit 1 and the channel connected thereto to ensure the accuracy of the measurement. During measurement, the electrical control cabinet 51 controls the analysis unit 4 to open the air supply unit 3 and connect it to the first air collecting unit 1, the air supply unit 3 is blocked from the second air collecting unit 1, the air supply unit 3 is blocked from the flushing unit 2, the first air collecting unit 1 and the second air collecting unit 1 are blocked from the flushing unit 2, and the sample gas collected by the first air collecting unit 1 is transported to the analysis unit 4 through the air supply unit 3 for analysis and monitoring.

[0096] Secondly, the second sampling point is measured: during flushing, the electrical control cabinet 51 controls the analysis unit 4 to close the air supply unit 3 and block the first air collecting unit and the second air collecting unit, and the air supply unit 3 is connected to the first outlet of the flushing unit 2, and the flushing gas is output from the first outlet of the flushing unit 2 into the air supply unit 3 to remove the residual sample gas and water vapor in the air supply unit 3 to ensure the accuracy of the measurement, and at the same time ensure that the air supply unit 3 has continuous airflow in the cold environment to avoid condensed water from freezing in the air supply unit 3. Finally, the flushing gas of the air collecting unit 1 is discharged from the pressure relief valve 38; while flushing, the electrical control cabinet 51 controls the second air collecting unit to be connected to the second outlet of the flushing unit 2, and the first air collecting unit is blocked from the second outlet of the flushing unit 2. The flushing gas is output from the second outlet of the flushing unit 2 into the air collecting unit 1 to remove the residual sample gas and water vapor in the second air collecting unit 1 and the channel connected to it to ensure the accuracy of the measurement. During measurement, electrical control cabinet 51 controls analysis unit 4 to open, connect air supply unit 3 to the second air collection unit, block air supply unit 3 from first air collection unit 1, block air supply unit 3 from flushing unit 2, and block the first and second air collection units from flushing unit 2. The sample gas collected by the second air collection unit is then transported via air supply unit 3 to analysis unit 4 for analysis and monitoring. This sequence of measuring the first and second sampling points is repeated to achieve continuous monitoring of multiple sampling points, even in cold environments.

[0097] The advantages of this embodiment are:

[0098] This embodiment can prevent condensate accumulation by regularly flushing the pipeline, thereby ensuring the normal operation of the system in low-temperature winter environments, which is particularly important in ensuring long-term monitoring.

[0099] This embodiment uses a floating cover to directly collect waste gas from the pool surface, which can adapt to aeration tanks of various shapes and sizes and is easy and flexible to install;

[0100] In this embodiment, through automated control and valve system switching, the system can ensure that each sampling point can perform efficient gas collection and analysis within a short time interval;

[0101] The system of this embodiment can be used in both roofed and roofless sewage treatment plants, and is usually used in conjunction with aeration tanks in sewage treatment plants. It can achieve multi-point monitoring and high-frequency continuous measurement of multiple greenhouse gases, and meet the needs of intermittent sampling in view of the relatively dispersed greenhouse gas emission sources of sewage treatment plants. This embodiment can sample multiple sampling points every 15 minutes and analyze different greenhouse gas gas components, which can meet the needs of sewage treatment plants of different sizes. This embodiment can quantify direct greenhouse gas emissions (N2O, CH4) in long-term monitoring activities, and can also evaluate the status of aeration equipment to determine whether renovation is needed. The system of this embodiment has a high degree of automation, which can reduce manual operations, and has a waterproof design to ensure stability and reliability in long-term operation;

[0102] It should be noted that the terms used to describe the positional relationships in the above examples and drawings are only for illustrative purposes and should not be construed as limiting this patent; the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all implementation methods here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A system for automatically monitoring greenhouse gas emissions from sewage treatment plants, characterized in that: include: A gas collecting unit (1), at least one gas supply unit (3), an analysis unit (4) and a flushing unit (2); each gas collecting unit (1) is connected to a first outlet of the flushing unit (2) and one end of the gas supply unit (3) via a three-way valve; a second outlet of the flushing unit (2) is connected to one end of the gas supply unit (3); and the other end of the gas supply unit (3) is connected to the analysis unit (4); and both the gas collecting unit (1) and the gas supply unit (3) are provided with a flushing outlet.

2. A system for automatically monitoring greenhouse gas emissions from sewage treatment plants according to claim 1, characterized in that: The flushing unit (2) comprises a flushing pump (21) and a first gas-liquid separator (22), wherein the outlet end of the first gas-liquid separator (22) is connected to the inlet end of the flushing pump (21).

3. The system for automatically monitoring greenhouse gas emissions from sewage treatment plants according to claim 1, characterized in that: The air delivery unit (3) comprises an air pump (35) and a second gas-liquid separator (31), and the inlet end of the air pump (35) is connected to the outlet end of the second gas-liquid separator (31).

4. A system for automatically monitoring greenhouse gas emissions from sewage treatment plants according to claim 3, characterized in that: The air supply unit (3) further includes a gas dryer (32) and a precision filter (33), wherein the inlet end of the gas dryer (32) is connected to the outlet end of the second gas-liquid separator (31), the outlet end of the gas dryer (32) is connected to the inlet end of the precision filter (33), and the outlet end of the precision filter (33) is connected to the inlet end of the air pump (35), so as to prevent the dried particles in the sample gas from entering the analysis unit (4) through the air pump (35).

5. A system for automatically monitoring greenhouse gas emissions from sewage treatment plants according to claim 4, characterized in that: The air supply unit (3) further includes a moisture sensor (34), and the moisture sensor (34) is arranged between the gas dryer (32) and the air pump (35).

6. A system for automatically monitoring greenhouse gas emissions from sewage treatment plants according to claim 5, characterized in that: The air supply unit (3) further comprises a pressure relief valve (38), and the pressure relief valve (38) is arranged at the outlet end of the air pump (35).

7. A system for automatically monitoring greenhouse gas emissions from sewage treatment plants according to claim 6, characterized in that: The air supply unit (3) further comprises a protective filter (36), the inlet end of the protective filter (36) and the inlet end of the pressure relief valve (38), and the protective filter (36) is used to increase its flow resistance when it comes into contact with moisture, thereby preventing moisture from passing through.

8. The system for automatically monitoring greenhouse gas emissions from sewage treatment plants according to claim 7, characterized in that: The air supply unit (3) further comprises a flow controller (37), the inlet end of the flow controller (37) is connected to the outlet end of the protection filter (36), and the outlet end of the flow controller (37) is connected to the analysis unit (4).

9. The system for automatically monitoring greenhouse gas emissions from sewage treatment plants according to claim 1, characterized in that: The air collecting unit (1) includes a floating hood (10), the floating hood (10) includes an air pipe (102), an air collecting hood (101), and a float (105) arranged on the side of the air collecting hood (101), the air pipe (102) is arranged above the air collecting hood (101), one end of the air pipe (102) is connected to the air collecting hood (101), the other end of the air pipe (102) is an exhaust port, and a side interface (103) is provided in the middle of the air pipe (102), and the side interface (103) is connected to the air supply unit (3) and the flushing unit (2).

10. The system for automatically monitoring greenhouse gas emissions from sewage treatment plants according to claim 9, characterized in that: The other end of the air pipe (102) is provided with a bent pipe (104), and the bent pipe (104) is used to make the exhaust port face the liquid surface.

Images