A device and method for determining greenhouse gas emission factors of drainage pipes

Abstract

The present invention provides a device and method for determining the greenhouse gas emission factor of a drainage pipeline, wherein the device is placed in the pipeline to measure the total amount of greenhouse gas generated in the pipeline, and the greenhouse gas emission factor of the drainage pipeline is calculated by measuring the total amount of greenhouse gas generated; and the device mainly includes a box, a gas intelligent detection module, a flow intelligent detection module and a reverse osmosis filter membrane. The method mainly derives the greenhouse gas emission factor of the drainage pipeline by measuring the total amount of greenhouse gas generated over a period of time and the volume of liquid flowing through the device. The patent of the present invention uses the in-situ measurement of greenhouse gas in the drainage pipeline to scientifically calculate the greenhouse gas emission factor of the drainage pipeline, thereby improving the accuracy of greenhouse gas calculation in the drainage pipeline.

Description

Technical Field

[0001] The present invention relates to the technical field of ecological environment protection, and in particular to a device and method for determining greenhouse gas emission factors of a drainage pipeline. Background Art

[0002] At present, the boundaries of carbon emission accounting in my country's drainage pipes are complex and greatly affected by factors such as region, process, and water quality, resulting in the lack of a unified and accurate carbon emission accounting method for the sewage treatment industry. The emission factor method currently mainly uses the method published by the IPCC as the main reference content, and is the most widely applicable and most commonly used carbon accounting method. At this stage, the determination of emission factors in the emission factor method is mainly based on the population size to infer the total amount of pollutants, and then calculate the carbon emissions. This method has imperfect boundaries, unclear emission nodes, incomplete coverage of carbon emission types, and lacks data to support its accuracy. Therefore, there are few reports on the method system for calculating greenhouse gas emission factors in drainage pipes under different scenarios. The existing drainage pipe gas emission total amount monitoring device cannot meet the research needs in this area, so the development of related supporting devices is urgently needed.

[0003] Overview of existing gas emission monitoring devices in the field of water treatment: 1. Portable flux box: mainly used to explore the measurement of greenhouse gas production in sewage treatment units. For example, the utility model patent with announcement number CN202267677U discloses a "portable static box for determining the greenhouse gas emission flux of water bodies". This device is mainly used for the measurement of gas flux between large water bodies such as sewage treatment units, rivers, and lakes. 2. Manhole flux box: mainly used to explore the measurement of the total amount of greenhouse gases generated by drainage networks and manhole systems. For example, the utility model patent with announcement number CN210626421U discloses a "portable flux box for measuring the greenhouse gas emission flux of drainage networks". This device collects gas samples in the drainage network system by using a syringe to draw 100ml of gas through a gas sampling tube each time.

[0004] The above existing devices are still insufficient for studying greenhouse gas emission factors in drainage pipes: 1. The size and shape of the existing devices cannot meet the function of being directly placed in the pipe to measure the gas flux between water and gas in situ; 2. The existing devices lack a greenhouse gas monitoring system with high time accuracy; 3. The existing devices use syringes and sampling tubes to collect samples at regular intervals, which is too cumbersome and consumes a lot of manpower and material resources; 4. The existing devices cannot measure the change process of water flow in the drainage pipe. Summary of the invention

[0005] In order to solve the problems of imperfect boundaries of the current method for determining the carbon emission factor of drainage pipes, unclear emission nodes, incomplete coverage of carbon emission types, and lack of data to support its accuracy, the present invention discloses a device and method for determining the greenhouse gas emission factor of drainage pipes.

[0006] The specific plan is as follows:

[0007] A device for measuring the greenhouse gas emission factor of a drainage pipe, characterized in that: the device is placed in the pipe, measures the total amount of greenhouse gas generated in the pipe, and calculates the greenhouse gas emission factor of the drainage pipe by measuring the total amount of greenhouse gas generated.

[0008] As a further improvement of the present invention, the device comprises a box, a gas intelligent detection module, a flow intelligent detection module and a reverse osmosis filter membrane. The material of the device is an organic plastic plate, and the size is determined according to the diameter of the required measurement pipeline.

[0009] As a further improvement of the present invention, the box body is a horizontally arranged circular tubular structure, and the middle part of its inner cavity is divided into an air cavity and a liquid cavity arranged upper and lower by a horizontally arranged reverse osmosis filter membrane. The reverse osmosis filter membrane can prevent the pipeline liquid from completely filling the box body, resulting in the inability to accurately measure the total amount of greenhouse gases produced. The two ends of the air cavity are sealed by closed doors, and the two ends of the liquid cavity are provided with movable doors adapted to their ends. The upper end of the movable door is connected to the lower end of the closed door by a hinge. When the flow rate is large, the valve can be flushed open, and when the flow rate is small, the valve can be closed by gravity. The gas intelligent detection module is placed in the air cavity, and the flow intelligent detection module is placed in the liquid cavity. The material of the box body is transparent acrylic.

[0010] As a further improvement of the present invention, the gas intelligent detection module includes a CH4 sensor, a N2O sensor, a CO2 sensor, and a first memory connected to each sensor, and the flow intelligent detection module is connected to the second memory via a cable. The gas intelligent detection module, the first memory, and the second memory are placed in a detection box with a through hole, and the detection box is placed in the air cavity.

[0011] The CH4 sensor adopts IGM100-CH4 sensor with a measuring range of 0-1000ppm and a resolution of 1ppm. The sensor is equipped with a data storage device and uses WLO Sin acquisition software. The software can monitor the concentration in real time and has data saving, querying and exporting functions.

[0012] As a further improvement of the present invention, the N2O sensor adopts an IGM100-N2O sensor with a measuring range of 0-1000ppm and a resolution of 1ppm. The sensor is equipped with a data storage device and uses WLO Sin acquisition software. The software can monitor the concentration in real time and also has data storage, query and export functions.

[0013] As a further improvement of the present invention, the CO2 sensor adopts IGM100-CO2 sensor with a measuring range of 0-5000ppm and a resolution of 1ppm. The sensor is equipped with a data storage device and uses WLO Sin acquisition software. The software can monitor the concentration in real time and also has data saving, querying and exporting functions.

[0014] As a further improvement of the present invention, the flow intelligent detection module adopts a pipe network Doppler flowmeter sensor with a water level range of 0.03-10m and a resolution of 0.001m; a flow velocity range of 0-10m / s and a resolution of 0.001m / s; the flow rate is calculated using the velocity area method, and through the WLO Sin acquisition software, the software can monitor hydrological indicators such as flow and water level in real time, and also has data storage, query and export functions.

[0015] As a further improvement of the present invention, each sensor is equipped with a memory for automatic storage of measurement data.

[0016] As a further improvement of the present invention, an arc-shaped fixing rope for fixing the box body is provided in the pipeline, which is used to fix the device inside the pipeline to ensure that it is not washed away by the water flow in the pipeline.

[0017] As a further improvement of the present invention, a drying box with a through hole is further provided in the air cavity of the box body, and a desiccant is contained in the drying box for drying the gas in the air cavity.

[0018] The present invention also provides a method for determining the greenhouse gas emission factor of a drainage pipeline, which is characterized by comprising the following steps:

[0019] S1: Install the tripod bracket in the pipeline to be monitored, and place the device on the tripod bracket to ensure that the direction in which the movable door of the lower part of the device opens is consistent with the direction of the water flow in the pipeline; under the impact of the water flow in the pipeline, the movable door will open, and the reverse osmosis filter membrane in the middle of the device will be difficult to pass through by water under normal pressure or low pressure, while CH4, N2O and CO2 small molecules can pass through the reverse osmosis filter membrane, so that the upper part of the device collects the greenhouse gases generated by the flowing liquid in the lower part;

[0020] S2: The lower part of the device uses a flow intelligent detection module to monitor water level and flow online, and the upper part uses a gas intelligent detection module to measure CH4, N2O and CO2 gas concentrations. The operator uses the WLO Sin acquisition software to monitor flow, water level hydrological indicators, and CH4, N2O and CO2 gas indicators in real time. In addition, it also has data storage, query and export functions;

[0021] S3: Use field sampling methods to measure pollutant concentrations at pipe network sampling points, and use laboratory simulation experiments to measure pollutant conversion rates; combine laboratory measurement parameters with monitoring device measurement data to obtain greenhouse gas emission factors based on the following relationship;

[0022]

[0023] Where EF is the emission factor of the gas to be measured, including kg CH4 / kg COD, kg CO2 / kg COD and kg N2O / kg TN; G t is the concentration of the gas to be measured in the upper part of the device at time t, ppm; V is the volume of the upper part of the device, m 3 ; M is the relative molecular mass of the gas, g / mol; 22.4 is the molar volume of the gas, L / mol; Q i is the liquid flow rate of the lower half of the device at the i-th moment, m 3 / s; Δt is the monitoring time interval of the flow intelligent detection module, s; C is the pollutant concentration in the pipeline water, mg / L; η T is the pollutant attenuation coefficient within the device measurement time t, d -1 ; t is the device measurement time, d.

[0024] The beneficial effects of the present invention are:

[0025] (1) The drainage network greenhouse gas emission total amount monitoring device of the present invention can be used for in-situ monitoring of the total amount of gas emissions from underground drainage networks;

[0026] (2) The present invention can automatically monitor greenhouse gases in drainage pipes and generate long-term series of greenhouse gas concentration measurement data;

[0027] (3) The present invention does not require the use of syringes and sampling tubes to collect gas in the device, which greatly reduces the manpower and material resources required for the experiment.

[0028] (4) The present invention can not only monitor the greenhouse gas generation process, but also automatically monitor the flow change process in the drainage pipe.

[0029] (5) The present invention has a simple structure, reasonable design and is easy to manufacture. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the use state of the device of the present invention in a pipe body;

[0031] Figure 2 It is a schematic diagram of the installation of the device of the present invention in a pipe body;

[0032] Figure 3 It is a schematic diagram of the internal structure of the device of the present invention;

[0033] Figure 4 This is a principle connection diagram of the gas intelligent detection module in the present invention;

[0034] Figure 5 This is a principle connection diagram of the flow intelligent detection module in the present invention;

[0035] Figure 6 This is a schematic diagram of the data format for greenhouse gas concentration and pipeline flow measurement;

[0036] Figure 7 This is a graph showing the change of pipeline flow over time.

[0037] List of reference numerals:

[0038] 1-arc fixing rope, 2-box, 3-reverse osmosis filter membrane, 4-CH4 sensor, 5-CO2 sensor, 6-N2O sensor, 7-pipeline, 8-flow intelligent detection module, 9-movable door, 10-sealed door, 11-hinge, 12-gas intelligent detection module, 13-cable, 14-first memory, 15-second memory, 16-detection box, 17-drying box, 18-U disk, 19-battery. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] The present invention provides a device for determining the greenhouse gas emission factor of a drainage pipe, such as Figure 1 , Figure 2 and Figure 3 As shown, the greenhouse gas emission factor measuring device for drainage pipes includes a box 2, a closed door 10, a movable door 9, a hinge 11, a reverse osmosis filter 3, a CH4 sensor 4, a CO2 sensor 5, a N2O sensor 6, a flow intelligent detection module 8, an arc-shaped fixed rope 1, etc. The gas and flow intelligent detection module, such as Figure 4 and Figure 5 As shown, it is mainly composed of a gas intelligent detection module 12, a flow intelligent detection module 8, a first memory 14, a cable 13 and a second memory 15, wherein the first memory 14 can be connected to a U disk and is equipped with a battery 19 for powering itself and the gas intelligent detection module, and the battery is rechargeable.

[0041] When testing the greenhouse gas emission factor in the drainage pipe 1, first fix the tripod in the pipe to be tested, and then fix the device on the tripod. When water enters the pipe, the movable door of the lower half of the device opens under the impact of the water flow, and the water flows into the lower half of the device. The generated greenhouse gas enters the upper half of the device through the reverse osmosis filter membrane, while the liquid is difficult to flow into the upper half of the device under normal pressure or low pressure conditions. Gas concentration (G t ) is measured using an intelligent sensor in the upper part of the device, the flow rate (Q i ) The lower part of the device is measured using intelligent sensors. The volume of the upper part of the device (V) can be calculated based on the size, and the pollutant concentration (C) and pollutant attenuation coefficient (η) of the pipeline water body can be calculated. T ) is measured in the sampling laboratory, the relative molecular mass of the gas (M) is obtained by consulting the data, and the device measurement time (t) and the flow intelligent detection module monitoring time interval (Δt) are determined by the operator according to the actual situation. The calculation method of the greenhouse gas emission factor in the drainage pipe based on real-time monitoring data is as follows:

[0042]

[0043] Using the above device and calculation method, the greenhouse gas emission factor of the drainage pipe with a diameter of 800mm is measured. The specific measurement steps are as follows:

[0044] S1: The cylindrical device is 1m long and 0.5m in radius. The volume of the upper part (V) is 0.39m 3 ; The relative molecular masses (M) of CO2, CH4 and N2O are 44, 16 and 44 respectively.

[0045] S2: According to the monitoring requirements in the book "Water and Wastewater Monitoring and Analysis Methods", the laboratory measured the COD and total nitrogen concentrations (C) in the sewage pipe to be 360 ​​mg / L and 25 mg / L respectively; the COD and total nitrogen attenuation coefficients (η T ) are 0.12d -1 and 0.04d -1 .

[0046] S3: The data format of the device measuring greenhouse gas concentration and pipeline flow is as follows Figure 6 , the measurement time (t) is 1 day, the flow intelligent detection module monitoring time interval (Δt) is 60 seconds. From the monitoring data, it can be seen that the CO2, CH4 and N2O gas concentrations in the upper half of the device are 4200ppm, 820ppm and 128ppm respectively after 1 day. The area enclosed by the flow rate change curve and the time coordinate axis can be used to calculate the ∑Q in the formula i ×Δt, the calculated result is 720m 3 .

[0047] S4: Figure 7 The measured data can be put into the formula to calculate the greenhouse gas emission factor EF of the drainage pipe with a pipe diameter of 800mm.

[0048] The calculation is as follows.

[0049]

[0050]

[0051]

[0052] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0053] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for determining greenhouse gas emission factors of drainage pipes, characterized in that: A device for determining greenhouse gas emission factors of drainage pipes is provided, the device being placed in a pipe (7) to measure the total amount of greenhouse gas generated in the pipe (7), and calculating the greenhouse gas emission factors of the drainage pipes by measuring the total amount of greenhouse gas generated. The device comprises a housing (2), a gas intelligent detection module (12), a flow intelligent detection module (8) and a reverse osmosis filter membrane (3). The housing (2) is a horizontally arranged circular tubular structure, the middle part of the inner cavity of which is divided into an air cavity and a liquid cavity arranged in an upper and lower direction by a horizontally arranged reverse osmosis filter membrane (3), the two ends of the air cavity being sealed by a sealed door (10), the two ends of the liquid cavity being provided with movable doors (9) adapted to the ends thereof, the upper end of the movable door (9) being connected to the lower end of the sealed door (10) by a hinge (11), the gas intelligent detection module (12) being placed in the air cavity, the flow intelligent detection module (8) being placed in the liquid cavity, and the material of the housing (2) being transparent acrylic. The method specifically comprises the following steps: S1: Install the tripod bracket in the pipe (7) to be monitored, and place the device on the tripod bracket to ensure that the direction in which the movable door (9) in the lower part of the device opens is consistent with the direction of the water flow in the pipe (7); under the impact of the water flow in the pipe (7), the movable door (9) will open, and the reverse osmosis filter membrane (3) in the middle of the device will be difficult for water to pass through under normal pressure or low pressure, and C H4 , N2 O and C O2 Small molecule gases can pass through, so that the upper part of the device collects greenhouse gases produced by the flowing liquid in the lower part; S2: The lower part of the device uses a flow intelligent detection module (8) to perform online monitoring of water level and flow, and the upper part uses a gas intelligent detection module (12) to measure the concentration of CH4, N2O and CO2 gases; the operator uses the WLO Sin acquisition software to monitor the flow, water level hydrological indicators, and CH4, N2O and CO2 gas indicators in real time, and it also has data storage, query and export functions; S3: Use field sampling methods to measure pollutant concentrations at pipe network sampling points, and use laboratory simulation experiments to measure pollutant conversion rates; combine laboratory measurement parameters with monitoring device measurement data to obtain greenhouse gas emission factors based on the following relationship; Where EF is the emission factor of the gas to be measured, including kg CH4 / kg COD, kg CO2 / kg COD and kg N2O / kgTN; G t is the concentration of the gas to be measured in the upper part of the device at time t, ppm; V is the volume of the upper part of the device, m 3 ; M is the relative molecular mass of the gas, g / mol; 22.4 is the molar volume of the gas, L / mol; Q i is the liquid flow rate of the lower half of the device at the i-th moment, m 3 / s; Δt is the monitoring time interval of the flow intelligent detection module, s; C is the pollutant concentration in the pipeline water, mg / L; η T is the pollutant attenuation coefficient within the device measurement time t, d -1 ; t is the device measurement time, d.

2. The device for determining greenhouse gas emission factors of drainage pipes according to claim 1, characterized in that: The gas intelligent detection module (12) comprises a CH4 sensor (4), a N2O sensor (6), a CO2 sensor (5) and a first memory (14) connected to each sensor; the flow intelligent detection module (8) is connected to a second memory (15) via a cable (13); the gas intelligent detection module (12), the first memory (14) and the second memory (15) are placed in a detection box (16) with a through hole; and the detection box (16) is placed in the air cavity.

3. The device for determining greenhouse gas emission factors of drainage pipes according to claim 2, characterized in that: The CH4 sensor (4) adopts the IGM100-CH4 sensor with a measuring range of 0-1000ppm and a resolution of 1ppm. The sensor is equipped with a data storage device and uses the WLO Sin acquisition software. The software can monitor the concentration in real time and also has the functions of data storage, query and export.

4. The device for determining greenhouse gas emission factors of drainage pipes according to claim 2, characterized in that: The N2O sensor (6) adopts an IGM100-N2O sensor with a measuring range of 0-1000ppm and a resolution of 1ppm. The sensor is equipped with a data storage device and uses WLO Sin acquisition software. The software can monitor the concentration in real time and also has data storage, query and export functions.

5. The device for determining greenhouse gas emission factors of drainage pipes according to claim 2, characterized in that: The CO2 sensor (5) adopts IGM100-CO2 sensor with a measuring range of 0-5000ppm and a resolution of 1ppm. The sensor is equipped with a data storage device and WLO Sin acquisition software. The software can monitor the concentration in real time and has data storage, query and export functions.

6. The device for determining greenhouse gas emission factors of drainage pipes according to claim 1, characterized in that: The flow intelligent detection module (8) comprises a pipe network Doppler flow meter sensor, the water level range is 0.03-10m, the resolution is 0.001m; the flow velocity range is 0-10m / s, the resolution is 0.001m / s; the flow velocity area method is used to calculate the flow, and the WLOSin acquisition software is used to monitor the flow, water level and hydrological indicators in real time, and the software also has the functions of data storage, query and export.

7. The device for determining greenhouse gas emission factors of drainage pipes according to claim 1, characterized in that: An arc-shaped fixing rope (1) for fixing the box body (2) is arranged inside the pipe (7).

8. The device for determining greenhouse gas emission factors of drainage pipes according to claim 1, characterized in that: A drying box (17) with a through hole is also provided in the air cavity of the box body (2), and a desiccant is contained in the drying box (17).

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