Modular sampling apparatus and method for greenhouse gases in sewage treatment plants

Abstract

The application relates to a modular sampling device and method for greenhouse gases in a sewage treatment plant, which comprises a body, a gas flow pipe, a gas flow meter, a switch valve, a sampling assembly and a gas pressure, temperature and liquid level detection module. The device is connected with each detection module signal through a processing module, the sampling point type is judged according to the gas flow, and open or closed sampling is performed accordingly. When open sampling is performed, the electromagnetic valve is opened, the gas collection cavity is communicated with the outside, and gas is introduced for sampling; when closed sampling is performed, the electromagnetic valve is closed, the gas collection cavity is closed with the outside, and gas is introduced. The sampling method applies the above modular sampling device. The modular sampling device of the application can be compatible with three different sampling point types, can meet all scene requirements of current greenhouse gas sampling in a sewage treatment plant, is more convenient to carry and use, and can reduce the equipment cost in the sampling process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sewage treatment, and particularly relates to a modular sampling device and method for greenhouse gases of a sewage treatment plant. BACKGROUND

[0002] During the operation of a sewage treatment plant, sampling of sewage is required to obtain the greenhouse gas emission flux of the sewage. The sampling scenarios are generally divided into unorganized emission sampling, fixed source emission sampling, and a combination scenario of part unorganized emission and part fixed source emission, and sampling of the aeration area and the non-aeration area is basically involved in each sewage treatment plant. For the above different scenarios, different types of sampling devices are generally used for sampling in the prior art, for example, an open flux box or a large-capacity gas bag is used for the aeration area, a closed flux box is used for the non-aeration area, and an atmospheric sampling instrument is used for the fixed source emission.

[0003] In actual operation, the frequency of carrying out greenhouse gas emission measurement of a single sewage treatment plant is once a year or once every two years, a large number of points are involved in each sampling, and usually one hour or so of sampling time is required for a single point, so a plurality of sets of sampling devices are generally used for synchronous sampling, which leads to the fact that the sampler needs to carry the above three types of sampling devices at the same time, and the number of each type of sampling device is usually more than one, resulting in difficulty in carrying and inconvenience in use. More importantly, since the sampling devices are not universal, different numbers of each type of sampling device need to be purchased according to the sampling point types of different sewage treatment plants, resulting in an increase in sampling cost.

[0004] In summary, the sampling device in the prior art has the defects of non-universality, inconvenience in carrying and use, and high sampling cost, and needs to be improved. SUMMARY

[0005] In order to solve the problems existing in the prior art, the present application aims to provide a modular sampling device and method for greenhouse gases of a sewage treatment plant. The modular sampling device of the present application can be compatible with three different sampling point types, is more convenient to carry and use, and can reduce the equipment cost in the sampling process.

[0006] The modular sampling device for greenhouse gases of a sewage treatment plant provided by the present application comprises a body, which has a gas collection cavity inside;

[0007] A gas flow pipe is in communication with the gas collection cavity at one end and in communication with the outside at the other end;

[0008] A gas flow meter is arranged on the gas flow pipe and used for detecting the gas flow in the gas flow pipe;

[0009] a switch valve disposed on the gas flow pipe for controlling opening and closing of the gas flow pipe;

[0010] a sampling assembly comprising a sampling pump and a sampling container, an air suction end of the sampling pump being in communication with the gas collection cavity, and an air outlet end being in communication with the sampling container;

[0011] a gas pressure detection module having a detection end disposed in the gas collection cavity for detecting internal gas pressure of the gas collection cavity;

[0012] a temperature detection module having a detection end disposed in the gas collection cavity for detecting internal temperature of the gas collection cavity;

[0013] a liquid level detection module having a detection end disposed in the gas collection cavity for detecting liquid surface height of the gas collection cavity;

[0014] a float body connected to the body for providing buoyancy;

[0015] a processing module signal-connected with the gas flow meter, the switch valve, the sampling pump, the gas pressure detection module, the temperature detection module and the liquid level detection module respectively;

[0016] the processing module determines the type of the sampling point according to the gas flow collected by the gas flow meter, and controls the modular sampling device to perform open sampling if the type of the sampling point is an aeration area, or to perform closed sampling if the type of the sampling point is a non-aeration area;

[0017] the open sampling comprises: allowing the electromagnetic valve to be in an open state, and introducing gas into the sampling container by the sampling pump;

[0018] the closed sampling comprises: allowing the electromagnetic valve to be in a closed state, and introducing gas into the sampling container by the sampling pump.

[0019] Preferably, the modular sampling device further comprises:

[0020] a flow guide fan disposed in the gas collection cavity, and the air flow direction is from the liquid surface to the sampling assembly.

[0021] Preferably, the modular sampling device further comprises:

[0022] a fixing assembly comprising a telescopic rod and a fixing buckle, one end of the telescopic rod being connected to the float body, and the other end being connected to the fixing buckle;

[0023] an indicator lamp disposed on the outer surface of the body and signal-connected with the processing module.

[0024] Preferably, the sampling container is a sampling tube and / or a sampling gas bag, the sampling assembly further comprises an extension tube and a sleeve, the sampling pump is detachably connected with the body, one end of the extension tube is detachably connected with the air suction end of the sampling pump, and the sleeve is detachably sleeved outside the extension tube.

[0025] A sampling method of the present application applies the modular sampling device as described above, comprising the following steps:

[0026] acquiring the type of the sampling point,

[0027] in response to the sampling point being an aeration area, opening the on-off valve of the gas flow pipe to make the gas collection cavity communicate with the outside world, starting the sampling pump to extract the gas in the gas collection cavity into the sampling container, collecting the temperature information of the gas collection cavity, and completing the open sampling process;

[0028] in response to the sampling point being a non-aeration area, closing the on-off valve of the gas flow pipe to make the gas collection cavity closed to the outside world, performing multiple closed sampling actions until the sampling times meet the requirements, and completing the closed sampling process;

[0029] the closed sampling action comprises: starting the sampling pump to extract the gas in the gas collection cavity into the sampling container, and collecting the liquid level information of the gas collection cavity, wherein the gas extracted in each closed sampling action is stored in an independent sampling container, and a certain time interval is set between adjacent closed sampling actions.

[0030] Preferably, before the open sampling process and the closed sampling process are performed, pressure stabilization detection is performed, and if the pressure stabilization detection passes, the open sampling process or the closed sampling process is performed;

[0031] the pressure stabilization detection comprises: making the on-off valve of the gas flow pipe and the air guide fan both in the open state, collecting the real-time air pressure in the gas collection cavity, and if the real-time air pressure meets the target air pressure interval for a certain time, judging that the pressure stabilization detection passes, otherwise judging that the pressure stabilization detection does not pass.

[0032] Preferably, when the type of the sampling point is a fixed source emission, the sampling pump is separated from the body, the extension tube is connected with the air suction end of the sampling pump, one end of the extension tube away from the sampling pump is inserted into the sampling point, and the sampling pump is started to extract the gas of the sampling point into the sampling container;

[0033] if a standard sampling hole is provided at the sampling point, the sleeve is sleeved outside the extension tube, the sleeve is put into the standard sampling hole, and the sampling pump is started to extract the gas of the sampling point into the sampling container.

[0034] Preferably, after obtaining the gas of the sampling point, further comprising:

[0035] The mass concentration of greenhouse gas is calculated according to the following formula:

[0036]

[0037] Wherein, C represents the mass concentration of greenhouse gas, C V represents the molar mass of greenhouse gas, T represents the temperature in the gas collection cavity at the time of sampling, and P represents the gas pressure in the gas collection cavity at the time of sampling;

[0038] In response to the sampling point being an aeration area, the greenhouse gas emission flux is calculated according to the following formula:

[0039] Flux a =C*Q1,

[0040] Wherein, Flux a represents the greenhouse gas emission flux of the aeration area, C represents the mass concentration of greenhouse gas, and Q1 represents the gas flow rate of the gas flow tube or the aeration flow rate of the sampling point;

[0041] In response to the sampling point being a non-aeration area, the greenhouse gas emission flux is calculated according to the following formula:

[0042]

[0043] Wherein, Flux b represents the greenhouse gas emission flux of the non-aeration area, V represents the volume of the gas collection cavity, A represents the cover area of the gas collection cavity at the water surface, h represents the height of the gas collection cavity, C represents the mass concentration of greenhouse gas, and t represents the duration of the sampling process, represents the mass concentration release rate of greenhouse gas;

[0044] In response to the sampling point being a fixed source emission, the greenhouse gas emission flux is calculated according to the following formula:

[0045] Flux c =C*Q2,

[0046] Wherein, Flux c represents the greenhouse gas emission flux of the fixed source emission, C represents the mass concentration of greenhouse gas, and Q2 represents the gas flow rate measured by the tail gas chimney or the rated flow rate.

[0047] Preferably, obtaining the type of the sampling point comprises:

[0048] Collecting the real-time gas flow rate at the gas flow tube, and if the real-time gas flow rate meets the condition of being greater than a preset flow rate threshold and the duration being greater than a preset time period threshold, determining that the type of the sampling point is an aeration area, otherwise determining that the type of the sampling point is a non-aeration area.

[0049] Preferably, the sampling method further comprises:

[0050] a threshold dynamic adjustment model is established, which takes the gas pressure, temperature and solid content of the sewage in the gas collection cavity as input, and takes the flow threshold and time period threshold as output;

[0051] When the type of the sampling point is obtained, the real-time collected gas pressure, temperature and solid content of the sewage in the gas collection cavity are input into the threshold dynamic adjustment model to obtain the corresponding flow threshold and time period threshold under the working condition, and the obtained flow threshold and time period threshold are applied to the type judgment of the sampling point.

[0052] The modular sampling device for greenhouse gas in the sewage treatment plant has the advantages that, according to the gas flow collected by the gas flow meter, the sampling point is determined to be an aeration area or a non-aeration area, and then the on-off of the switch valve is controlled, so that the gas collection cavity is in communication with the outside to form open sampling, or is closed with the outside to form closed sampling, which can meet the sampling requirements of different sampling points.

[0053] In addition, the sampling assembly of the present application further comprises a detachable sampling pump, an extension pipe and a sleeve, which can be detached to meet the sampling requirements of fixed source emissions, so that the present application can be applied to the sampling process of three different sampling points, has universality, and does not need to carry multiple different types of sampling equipment during sampling, is more convenient to carry and use, and can reduce the equipment cost of the sampling process.

[0054] The present application further provides a sampling method using the above-mentioned modular sampling device, proposes a sampling process corresponding to different types of sampling points, and further proposes a simplified greenhouse gas emission flux calculation method in combination with the parameters that can be collected by the device, which simplifies the on-site operation of the sampling personnel and helps to improve the sampling efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0055] Figure 1 is a structural schematic diagram of the modular sampling device of the present application;

[0056] Figure 2 is a cooperation structural schematic diagram of the sampling assembly and the box of the present application;

[0057] Figure 3 is a cooperation structural schematic diagram of the guide fan and the box of the present application;

[0058] Figure 4 is a structural schematic diagram of the sampling assembly of the present application when sampling fixed source emissions;

[0059] Figure 5is a structural block diagram of the modular sampling device described in the present application.

[0060] BRIEF DESCRIPTION OF DRAWINGS: 1 - body, 2 - gas flow pipe, 3 - gas flow meter, 4 - on-off valve, 5 - sampling assembly, 51 - sampling pump, 52 - sampling container, 521 - sampling tube, 522 - sampling gas bag, 53 - extension pipe, 54 - sleeve, 6 - gas pressure detection module, 7 - temperature detection module, 8 - liquid level detection module, 9 - float, 91 - ring buckle, 10 - processing module, 11 - guide fan, 12 - fixing assembly, 121 - telescopic rod, 122 - fixing buckle, 13 - indicator light. DETAILED DESCRIPTION

[0061] As shown in Figures 1-5 , a modular sampling device for greenhouse gases in a sewage treatment plant described in the present application, comprising:

[0062] Body 1, the body 1 is a cylinder, hollow inside to form a gas collection cavity.

[0063] Gas flow pipe 2, the gas flow pipe 2 is "L" shaped structure, one end into the gas collection cavity and the gas collection cavity communication, the other end extends to the side of the body 1, and communicates with the outside.

[0064] Gas flow meter 3, which is provided on the gas flow pipe 2, is located at one end close to the body 1, for detecting the gas flow through the gas flow meter 3.

[0065] On-off valve 4, specifically electromagnetic valve, can be controlled by electrical signal open and close. The on-off valve 4 is arranged on the gas flow pipe 2, and the opening and closing of the gas flow pipe 2 is controlled through the on-off valve 4, so as to control the communication state between the gas collection cavity and the outside, so that the gas collection cavity is in closed state or in communication state with the outside.

[0066] Sampling assembly 5, which includes sampling pump 51 and sampling container 52, the suction end of the sampling pump 51 communicates with the gas collection cavity, and the gas outlet end communicates with the sampling container 52. When the sampling pump 51 works, the gas in the gas collection cavity is extracted into the sampling container 52.

[0067] Gas pressure detection module 6, such as gas gauge, is arranged on one side of the top surface of the body 1, the detection end, i.e. the gas pressure probe, extends into the gas collection cavity, for detecting the internal gas pressure of the gas collection cavity.

[0068] Temperature detection module 7, such as electronic thermometer, is arranged on one side of the top surface of the body 1, adjacent to the gas pressure detection module 6, the detection end, i.e. the temperature probe, extends into the gas collection cavity, for detecting the internal temperature of the gas collection cavity.

[0069] The liquid level detection module 8, such as an ultrasonic liquid level meter, is located on one side of the top surface of the main body 1, adjacent to the temperature detection module 7. The detection end, i.e. the liquid level probe, extends into the gas collection chamber to detect the liquid level height in the gas collection chamber.

[0070] The float 9, such as an internally inflated rubber ring, is connected to the body 1. Specifically, it is fitted on the outer bottom of the body 1 to provide buoyancy so that the body 1 can float on the surface of the monitored water area.

[0071] The processing module 10 uses a processor or controller with computing power, such as an MCU or PLC. The processing module 10 is connected to the gas flow meter 3, the switching valve 4, the sampling pump 51, the gas pressure detection module 6, the temperature detection module 7, and the liquid level detection module 8 respectively. It is used to receive the detection signals from each acquisition end and control the start and stop of the switching valve 4 and the sampling pump 51.

[0072] The processing module 10 determines the type of sampling point based on the gas flow rate collected by the gas flow meter 3. If the type of sampling point is an aeration area, it controls the modular sampling device to perform open sampling. If the type of sampling point is a non-aeration area, it controls the modular sampling device to perform closed sampling.

[0073] The open sampling includes: putting the solenoid valve in the open state, that is, the gas collection chamber is in communication with the outside, and introducing gas into the sampling container 52 through the sampling pump 51;

[0074] The closed sampling includes: keeping the solenoid valve in the closed state, that is, keeping the gas collection chamber closed from the outside, and introducing gas into the sampling container 52 through the sampling pump 51.

[0075] Furthermore, in this embodiment, as Figure 3 As shown, the modular sampling device also includes two flow guide fans 11, which are symmetrically arranged on both sides of the gas collection chamber along the axis of the main body 1. The flow guide fans 11 are connected and fixed to the inner wall of the gas collection chamber. The flow guide fans 11 are vertically arranged, and their airflow direction is from bottom to top, that is, from the liquid surface to the direction where the sampling component 5 is located. When the flow guide fans 11 are working, they can drive the uniform flow in the gas collection chamber to achieve the effect of homogeneous gas concentration in the gas collection chamber.

[0076] Furthermore, in this embodiment, the modular sampling device further includes:

[0077] The fixing assembly 12 comprises a telescopic rod 121 and a fixing buckle 122. The telescopic rod 121 is connected to the floating body 9 at one end. For example, the outer side of the floating body 9 is provided with a plurality of ring buckles 91, and the other end of the telescopic rod 121 is provided with a ring buckle 91 matched with the ring buckles 91. The telescopic rod 121 is connected to the floating body 9 through the ring buckles 91. Specifically, the telescopic rod 121 is a multi-section sleeve structure. The multi-section rod members are sequentially and slidably sleeved, so that the length of the telescopic rod 121 as a whole can be adjusted in length, so as to be flexibly adjusted according to the distance between the laying point and the fixing point. The fixing buckle 122 is a claw-shaped fixing buckle 122, which can be buckled and fixed on the rail or fence of the shore base, so as to fix the body 1 at the sampling point, and avoid the floating displacement of the sampling device.

[0078] The modular sampling device also comprises indicator lights 13, the number of which is two, namely a red light and a green light, which are used to indicate different working states of the device. The indicator lights 13 are arranged on the top surface of the body 1 and are signal-connected with the processing module 10. The processing module 10 controls different indicator lights 13 to light up according to the sampling process, so as to indicate the sampling state.

[0079] Further, in the embodiment, please refer to Figure 4 The sampling container 52 is a sampling tube 521 and / or a sampling gas bag 522, which is selected and arranged according to the actual situation. The sampling assembly 5 also comprises an extension pipe 53 and a sleeve 54. The extension pipe 53 and the sleeve 54 are both hollow cylindrical structures. The sampling pump 51 is detachably connected to the body 1, so that the sampling pump 51 can be detached from the body 1. One end of the extension pipe 53 is detachably connected to the air suction end of the sampling pump 51. The sleeve 54 is detachably sleeved on the outer side of the extension pipe 53. When sampling the fixed source emission, the sampling pump 51 can be detached from the body 1. The extension pipe 53 is connected to the air suction end of the sampling pump 51. Then the other end of the extension pipe 53 is inserted into the sampling position for sampling. If the sampling point is a standard sampling point, the sleeve 54 is installed on the outer side of the extension pipe 53 for sampling. The structure of the embodiment makes the modular sampling device of the application applicable to the sampling points of the three types, i.e. the aeration area, the non-aeration area and the fixed source emission.

[0080] The embodiment also provides a sampling method for greenhouse gases in a sewage treatment plant, which is applied to the modular sampling device described above and comprises the following steps:

[0081] acquiring the type of the sampling point,

[0082] In response to the sampling point being an aeration area, the opening and closing valve 4 of the gas flow pipe 2 is opened, so that the gas collection cavity is in communication with the outside. The sampling pump 51 is started to extract the gas in the gas collection cavity into the sampling container 52, and the temperature information of the gas collection cavity is collected, so as to complete the open sampling process.

[0083] In response to the sampling point being a non-aeration area, the switch valve 4 of the gas flow pipe 2 is closed to seal the gas collection cavity from the outside, multiple closed sampling actions are performed until the number of sampling times meets the requirement, and the closed sampling process is completed;

[0084] The closed sampling action includes: starting the sampling pump 51 to extract the gas in the gas collection cavity into the sampling container 52, and collecting the liquid level information of the gas collection cavity, wherein the gas extracted in each closed sampling action is stored in an independent sampling container 52, and a certain time interval is set between adjacent two closed sampling actions.

[0085] Further, in the embodiment, to ensure stable gas flow during sampling, pressure stabilization detection is required before sampling, which is specifically as follows:

[0086] Before performing the open sampling process and the closed sampling process, pressure stabilization detection is performed, and if the pressure stabilization detection passes, the open sampling process or the closed sampling process is performed;

[0087] The pressure stabilization detection includes: the switch valve 4 of the gas flow pipe 2 and the flow guide fan 11 are both in an open state, the real-time gas pressure in the gas collection cavity is collected, and if the real-time gas pressure meets the target gas pressure interval for a certain time, it is judged that the pressure stabilization detection passes, otherwise it is judged that the pressure stabilization detection does not pass.

[0088] In this step, the gas collection cavity is connected to the outside, and the flow guide fan 11 is started to make the gas in the gas collection cavity flow uniformly, thereby realizing the effect of uniform gas concentration in the gas collection cavity. The real-time gas pressure of the gas collection cavity is collected and recorded as time series data. If the real-time gas pressure meets the target gas pressure interval for a certain time, for example, at the 1st second of starting the pressure stabilization detection, the gas pressure value at that moment is recorded, and ±10Pa of the gas pressure value is taken as the target gas pressure interval. If the gas pressure is kept in the target gas pressure interval for 2 minutes in the pressure stabilization detection process, it is judged that the gas pressure in the gas collection cavity is stable, and the subsequent sampling can be performed. Otherwise, it is judged that the gas pressure is unstable, and sampling is not suitable for the moment. Sampling can be performed after the gas pressure is stabilized.

[0089] Further, in the embodiment, as shown in Figure 4 When the type of the sampling point is a fixed source emission, the sampling pump 51 is detached from the body 1, the extension pipe 53 is connected to the gas extraction end of the sampling pump 51, one end of the extension pipe 53 away from the sampling pump 51 is inserted into the sampling point, and the sampling pump 51 is started to extract the gas of the sampling point into the sampling container 52;

[0090] If a standard sampling hole is opened at the sampling point, the sleeve 54 is sleeved outside the extension pipe 53, and the sleeve 54 is put into the standard sampling hole, and the sampling pump 51 is started to extract the gas at the sampling point into the sampling container 52.

[0091] Further, in the embodiment, after obtaining the gas at the sampling point, the method further comprises:

[0092] The mass concentration of the greenhouse gas is calculated according to the following formula:

[0093]

[0094] Wherein, C represents the mass concentration of the greenhouse gas, C V represents the molar mass of the greenhouse gas, T represents the temperature in the gas collection cavity during sampling, and P represents the gas pressure in the gas collection cavity during sampling. It should be noted that the temperature T and the gas pressure P in the gas collection cavity during sampling can use the instantaneous temperature and gas pressure at the beginning of sampling as the numerical calculation, or can be calculated by calculating the average, mode, median, etc. of the temperature and gas pressure during the entire sampling process. The embodiment is not limited in this regard.

[0095] In response to the sampling point being an aeration area, the greenhouse gas emission flux is calculated according to the following formula:

[0096] Flux a = C * Q1,

[0097] Wherein, Flux a represents the greenhouse gas emission flux of the aeration area, C represents the mass concentration of the greenhouse gas, and Q1 represents the gas flow rate of the gas flow pipe 2 or the aeration flow rate of the sampling point. Similarly, the gas flow rate of the gas flow pipe 2 or the aeration flow rate of the sampling point Q1 can be calculated using the instantaneous value at the beginning of sampling, or the average, mode, median, etc. of the sampling process.

[0098] In response to the sampling point being a non-aeration area, the greenhouse gas emission flux is calculated according to the following formula:

[0099]

[0100] Wherein, Flux b represents the greenhouse gas emission flux of the non-aeration area, V represents the volume of the gas collection cavity, A represents the cover area of the gas collection cavity on the water surface, h represents the height of the gas collection cavity, C represents the mass concentration of the greenhouse gas, and t represents the duration of the sampling process, represents the mass concentration release rate of the greenhouse gas;

[0101] In response to the sampling point being a fixed source emission, the greenhouse gas emission flux is calculated according to the following formula:

[0102] Flux c =C*Q2,

[0103] Wherein, Flux c represents the greenhouse gas emission flux of the fixed source emission, C represents the greenhouse gas mass concentration, Q2 represents the gas flow rate measured by the tail gas chimney or the rated flow rate, and similarly, the gas flow rate measured by the tail gas chimney or the rated flow rate Q2 can be calculated by using the instantaneous value at the beginning of sampling, or the average value, mode, median, etc. during the sampling process.

[0104] Further, in the embodiment, the type of the sampling point is determined by the gas flow rate in the gas flow tube 2, specifically:

[0105] The real-time gas flow rate at the gas flow tube 2 is collected, and if the real-time gas flow rate satisfies the condition of being greater than a preset flow rate threshold value and the duration being greater than a preset time period threshold value, it is determined that the type of the sampling point is an aeration area, otherwise it is determined that the type of the sampling point is a non-aeration area.

[0106] For the aeration area, since the water body is in a continuous aeration process, under the condition that other parameters such as air pressure and the rotation speed of the flow guide fan 11 are the same, the gas flow rate per unit time is usually greater than that of the non-aeration area, and there is a relatively obvious difference between the two, so this index can be used to distinguish the aeration area and the non-aeration area, that is, by the preset threshold value determination method, if the gas flow rate is greater than the preset threshold value, it is determined that the aeration area, and if it is less than or equal to the preset threshold value, it is determined that the non-aeration area. The embodiment can effectively determine the aeration area and the non-aeration area by using the gas flow rate as an index, and the determination result is relatively accurate. Moreover, the gas flow rate is the data that needs to be collected during the sampling process, and it is not necessary to set up other collection devices for collection and determination, so it has good practicability.

[0107] Further, in the embodiment, for different water bodies and different environmental factors, the gas flow rate will be greatly affected, for example, since the gas collection cavity is a relatively closed and small space, the temperature and air pressure in the gas collection cavity will affect the gas flow rate collected by the gas flow meter 3 at the end of the gas flow tube 2, and the influence of environmental factors on the gas flow rate detection result needs to be considered. In addition, the solid content in the sewage will also affect the gas discharged after aeration, and thus have a great influence on the gas flow rate.

[0108] However, the modular sampling device of the present application needs to be applied to the diversified sampling point environments of different sewage treatment plants. If uniform flow rate threshold values and time period threshold values are used, it is difficult to ensure accurate sampling point type determination in water body environments with large differences. If the sampling personnel calculate and adjust the threshold values on site according to the actual water body environment, the sampling efficiency will be affected.

[0109] Therefore, in this embodiment, a threshold dynamic adjustment model is established, which takes the air pressure, temperature and solid content of the wastewater in the gas collection chamber at the time of sampling as inputs and the flow rate threshold and time period threshold as outputs.

[0110] When determining the type of a sampling point, the real-time collected air pressure, temperature, and solid content of the wastewater in the gas collection chamber are input into the threshold dynamic adjustment model to obtain the corresponding flow rate threshold and time period threshold under the operating condition. The obtained flow rate threshold and time period threshold are then applied to the type determination of the sampling point.

[0111] For example, using a decision tree as the threshold dynamic adjustment model includes the following steps:

[0112] Data Collection: Sample data was collected, including the gas pressure and temperature in the gas collection chamber, the solid content of the wastewater, and the gas flow rate during the sampling process (all parameters are instantaneous values ​​at the time of sampling or average values ​​during the sampling process, selected according to the actual situation). Each set of sample data includes two sub-data sets: data from the aeration zone and data from the non-aeration zone. For the aeration zone and non-aeration zone data in the same set of data, the gas pressure, temperature, and solid content are the same. The minimum gas flow rate of the aeration zone data and the maximum gas flow rate of the non-aeration zone data during the sampling process were taken, and the median of the maximum and minimum values ​​was taken as the flow rate threshold for that set of sample data. For the time period threshold, based on the maximum difference in gas flow rate between the aeration area data and the non-aeration area data under this environment, a difference benchmark value is preset, for example, 60% or 80% of the maximum difference is taken as the difference benchmark value. The moment when the flow rate difference between the two sets of sub-data at the same time during the sampling process first exceeds the preset difference benchmark value is obtained. The time interval between this moment and the sampling start moment is taken as the time period threshold, so as to ensure that the time period threshold can cover the moment when there is a significant difference between the aeration area and the non-aeration area.

[0113] It should be noted that the aforementioned sample data can be obtained through on-site testing, simulation, or data augmentation.

[0114] Model building: Extract features from the collected data, such as average air pressure, average temperature, and percentage of solids content.

[0115] Using the aforementioned sample data to train a decision tree model, the model will learn how to predict the corresponding flow rate threshold and time period threshold based on average air pressure, average temperature, and percentage of solids content.

[0116] By training with sample data, the model will establish a mapping relationship between air pressure, temperature, solid content and corresponding flow rate thresholds and time period thresholds.

[0117] Real-time data input: input real-time monitored air pressure, temperature, solid content into the decision tree model.

[0118] Threshold prediction: the model predicts the current flow threshold and period threshold according to the input data.

[0119] Applying the predicted flow threshold and period threshold to the sampling process of the working condition can adapt the flow threshold and period threshold to the working condition, and thus accurately judge the type of sampling point under the working condition.

[0120] The sampling process of the modular sampling device of the embodiment will be described in detail below in combination with the above content:

[0121] One end of the safety rope is connected to a fixed place such as a railing on the shore, and the other end is connected to the ring buckle 91 of the float body 9 of the sampling device. Two telescopic rods 121 (only one is shown in the figure) are respectively connected to the ring buckle 91 of the float body 9 of the sampling device at one end, and the sampling device is smoothly put into the water body. The fixing buckle 122 at the other end of the telescopic rod 121 is buckled on the fixed place such as the railing on the shore, the telescopic rod 121 is extended to a length of 2-4 meters, and the sampling device is pushed to 1 / 2 of the water corridor.

[0122] Before sampling starts, the sampling device enters the identification mode, and the switch valve 4 is opened, and the gas flow meter 3 is opened. If the value of the gas flow meter 3 exceeds 200 ml / min and the duration exceeds 3 min, the sampling device performs open sampling. If the above conditions are not met, the sampling device performs closed sampling.

[0123] Open sampling process: switch valve 4 is opened—gas flow meter 3 is opened—airflow fan 11 is opened—air pressure detection module 6 is started—temperature detection module 7 is started—indicator light 13 is long bright red—5 min later, air pressure detection module 6 and sampling pump 51 are linked to open—If the air pressure detection module 6 remains fluctuating for 2 min, the fluctuation does not exceed ±10 Pa, the air pressure count value at this time is stored—gas flow meter 3, the value of the gas flow meter 3 at this time is stored—temperature count value is stored—signal light is long bright green—sampling pump 51 is started for 15 s, and the gas in the body 1 is extracted to the sampling gas bag 522—exhaustion ends, sampling pump 51 stops sampling—5 min waiting time—recycle green step twice—collect gas sample 3 times, sampling ends.

[0124] Closed sampling process: switch valve 4 opens-gas flow meter 3 opens- guide fan 11 opens- air pressure detection module 6 starts- temperature detection module 7 starts- indicator light 13 long bright red- 5 min after air pressure detection module 6 and sampling pump 51 linkage opens- if air pressure detection module 6 remains 2 min fluctuation not more than ± 10Pa- signal light long green- switch valve 4 closes- gas flow meter 3 closes- store temperature, air pressure- gas sampling pump 51 starts to extract gas sample to No. 1 gas sampling bag, while liquid level detection module 8 records the liquid level height at this time as No. 1 height- close gas sampling pump 51- 10 min waiting time- store temperature, air pressure- gas sampling pump 51 starts to extract gas sample to No. 2 gas sampling bag, while liquid level detection module 8 records the liquid level height at this time as No. 2 height- close gas sampling pump 51- in turn to complete No. 6 gas sampling bag- signal light flickering red light, indicating the end of sampling.

[0125] The fixed source emission and subsequent greenhouse gas emission flux are the same as the above, which can be understood by referring to the description above, and will not be repeated here.

[0126] In the description of the present application, it should be understood that the orientation words such as "front, back, up, down, left, right", "transverse, vertical, horizontal" and "top, bottom" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate and imply that the devices or elements referred to must have a particular orientation or be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the scope of protection of the present application.

[0127] For those skilled in the art, other various corresponding changes and modifications can be made according to the above described technical solutions and concepts, and all of these changes and modifications should belong to the protection scope of the claims of the present application.

Claims

1. A modular sampling device for greenhouse gases in wastewater treatment plants, characterized in that, include: The main body has an internal air-collecting chamber; A gas flow pipe, one end of which is connected to the gas collection chamber and the other end of which is connected to the outside; A gas flow meter is installed on the gas flow tube to detect the gas flow rate in the gas flow tube; A switching valve is installed on the gas flow pipe to control the opening and closing of the gas flow pipe; A sampling assembly includes a sampling pump and a sampling container, wherein the pump's suction end is connected to the gas collection chamber and its outlet end is connected to the sampling container. A pressure detection module, the detection end of which is set inside the air collection chamber, is used to detect the internal air pressure of the air collection chamber; A temperature detection module, with its detection end located inside the gas collecting chamber, is used to detect the internal temperature of the gas collecting chamber; A liquid level detection module, with its detection end located inside the gas collection chamber, is used to detect the liquid level height in the gas collection chamber; A floating body, which is connected to the main body, is used to provide buoyancy; The processing module is connected to the gas flow meter, the switching valve, the sampling pump, the gas pressure detection module, the temperature detection module, and the liquid level detection module respectively. The processing module determines the type of sampling point based on the gas flow rate collected by the gas flow meter. If the type of sampling point is an aeration area, the module controls the modular sampling device to perform open sampling. If the type of sampling point is a non-aeration area, the module controls the modular sampling device to perform closed sampling. The open sampling includes: keeping the switch valve in the open state and introducing gas into the sampling container through the sampling pump; The closed-loop sampling includes: keeping the switching valve in the closed state and introducing gas into the sampling container through the sampling pump.

2. The modular sampling device for greenhouse gases in wastewater treatment plants according to claim 1, characterized in that, Also includes: A flow guide fan is disposed inside the gas collection chamber, and the airflow direction is from the liquid surface to the sampling component.

3. The modular sampling device for greenhouse gases in wastewater treatment plants according to claim 1, characterized in that, Also includes: The fixing assembly includes a telescopic rod and a fixing buckle, one end of the telescopic rod being connected to the float and the other end being connected to the fixing buckle; An indicator light is disposed on the outer surface of the main body and is signal-connected to the processing module.

4. The modular sampling device for greenhouse gases in wastewater treatment plants according to claim 1, characterized in that, The sampling container is a sampling tube and / or a sampling gas bag. The sampling assembly also includes an extension tube and a sleeve. The sampling pump is detachably connected to the main body. One end of the extension tube is detachably connected to the air extraction end of the sampling pump. The sleeve is detachably fitted onto the outside of the extension tube.

5. A method for sampling greenhouse gases in a wastewater treatment plant, employing the modular sampling equipment as described in any one of claims 1-4, characterized in that, Includes the following steps: Obtain the type of sampling point. In response to the fact that the sampling point is an aeration area, the switch valve of the gas flow pipe is opened to connect the gas collection chamber with the outside world. The sampling pump is started to draw the gas in the gas collection chamber into the sampling container and collect the temperature information of the gas collection chamber to complete the open sampling process. In response to the fact that the sampling point is a non-aeration area, the switch valve of the gas flow pipe is closed to seal the gas collection chamber from the outside world, and multiple closed sampling actions are performed until the number of samplings meets the requirements, thus completing the closed sampling process. The closed sampling action includes: starting the sampling pump to extract the gas in the gas collection chamber into the sampling container, and collecting the liquid level information of the gas collection chamber. The gas extracted in each closed sampling action is stored in an independent sampling container, and there is a certain time interval between two adjacent closed sampling actions.

6. The sampling method according to claim 5, characterized in that, Before executing the open sampling process and the closed sampling process, a voltage regulation test is performed. If the voltage regulation test passes, the open sampling process or the closed sampling process is executed. The pressure stabilization test includes: turning on the gas flow pipe valve and the flow guide fan, collecting the real-time gas pressure in the gas collection chamber, and if the real-time gas pressure is maintained within the target gas pressure range for a certain period of time, the pressure stabilization test is considered to have passed; otherwise, the pressure stabilization test is considered to have failed.

7. The sampling method according to claim 5, characterized in that, When the sampling point is a stationary source emission, the sampling pump is separated from the main body, the extension tube is connected to the suction end of the sampling pump, the end of the extension tube away from the sampling pump is extended into the sampling point, and the sampling pump is started to extract the gas from the sampling point into the sampling container. If a standard sampling hole is provided at the sampling point, the sleeve is placed on the outside of the extension tube and inserted into the standard sampling hole. The sampling pump is then started to extract the gas from the sampling point into the sampling container.

8. The sampling method according to claim 7, characterized in that, After obtaining the gas at the sampling point, the process also includes: Calculate the mass concentration of greenhouse gases using the following formula: ， in, Indicates the mass concentration of greenhouse gases. Indicates the molar mass of greenhouse gases. This indicates the temperature inside the gas collection chamber during sampling. This indicates the air pressure inside the gas collection chamber during sampling; Since the sampling point is an aeration zone, the greenhouse gas emission flux is calculated according to the following formula: ， in, This indicates the greenhouse gas emission flux in the aeration zone. Indicates the mass concentration of greenhouse gases. This indicates the gas flow rate of the gas flow tube or the aeration flow rate at the sampling point; In response to the fact that the sampling point is a non-aeration area, the greenhouse gas emission flux is calculated according to the following formula: ， in, This represents the greenhouse gas emission flux in the non-aeration zone. This indicates the volume of the gas collecting chamber. This indicates the area of ​​the air collection chamber covering the water surface. Indicates the height of the gas collecting chamber. Indicates the mass concentration of greenhouse gases. Indicates the duration of the sampling process. Indicates the mass concentration release rate of greenhouse gases; In response to the fact that the sampling point is a stationary source of emissions, the greenhouse gas emission flux is calculated according to the following formula: ， in, This represents the greenhouse gas emission flux from stationary sources. Indicates the mass concentration of greenhouse gases. This indicates the gas flow rate or rated flow rate measured at the exhaust gas chimney.

9. The sampling method according to claim 5, characterized in that, The types of sampling points obtained include: The real-time gas flow rate at the gas flow pipe is collected. If the real-time gas flow rate is greater than a preset flow rate threshold and the duration is greater than a preset time period threshold, the sampling point is determined to be an aeration area; otherwise, the sampling point is determined to be a non-aeration area.

10. The sampling method according to claim 9, characterized in that, Also includes: A threshold dynamic adjustment model is established, which takes the air pressure, temperature and solid content of the wastewater in the gas collection chamber at the time of sampling as inputs and the flow rate threshold and time period threshold as outputs. When determining the type of a sampling point, the real-time collected air pressure, temperature, and solid content of the wastewater in the gas collection chamber are input into the threshold dynamic adjustment model to obtain the corresponding flow rate threshold and time period threshold under the operating condition. The obtained flow rate threshold and time period threshold are then applied to the type determination of the sampling point.

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