Device for measuring greenhouse gas on water-gas interface in water level descending process and use method of device

Abstract

Reservoir is an important way for human to modify nature, CO2 accounts for 4% of manual emission, and CH4 is as high as 20%. According to the reservoir operation characteristics and the sediment greenhouse gas generation rule, CO2 and CH4 generated by sediment are obviously released in the water release period, and annual greenhouse gas emission of the reservoir mainly comes from the period. Therefore, the invention relates to a device and a measuring method for accurately quantifying greenhouse gas emission in the water level descending process, and technical support is provided for reservoir carbon circulation. A device for measuring water-gas interface greenhouse gas in the water level descending process comprises a cylindrical body, a graduated scale is arranged on one side of the cylindrical body, a foam plate is installed on the inner wall of the cylindrical body and communicated with a water pumping opening, the water pumping opening is connected with an inlet of a TPU pipe, and one end of a water pump is connected with an inlet of a water quality analyzer and an inlet of a water-gas separation device in parallel. And a gas outlet of the water-gas separation device is communicated with a gas analyzer.

Description

Technical Field

[0001] The invention relates to the field of carbon cycle of aquatic ecosystems, and in particular to a device for measuring greenhouse gases at a water-air interface during a water level drop and a method for using the device. Background Art

[0002] CO2, CH4 and other important greenhouse gases in reservoir water bodies mainly come from sediments. However, the greenhouse gases released into the atmosphere are closely related to water level changes. Usually, a small part of the greenhouse gases produced by sediments will be transported to the water-air interface and then released into the atmosphere. However, the drop in water levels will significantly promote the upward diffusion of greenhouse gases or their upward transport in the form of bubbles.

[0003] At present, there is no device that can accurately quantify the amount of water level change and the volume of greenhouse gas released at the water-air interface. Studies have shown that greenhouse gases produced by human factors are the main cause of frequent extreme weather. Among them, reservoir CO2 accounts for about 4% of human emissions, while CH4 is as high as 20%. Therefore, in order to measure the amount of greenhouse gas released when the reservoir water level drops, this device was invented to provide a scientific basis for reservoir carbon emission reduction.

[0004] Reference article for water-gas separation device 15: A fast-response automated gas equilibrator (FaRAGE) for continuous in situ measurement of CH4 and CO2 dissolved in water.

[0005] Available at: https: / / doi.org / 10.5194 / hess-24-3871-2020. Summary of the invention

[0006] The present invention aims to solve the problem of accurately measuring the maximum total emission and maximum emission rate of greenhouse gases CO2 and CH4 emitted from sediments when the water level drops, and to solve the problem of deviation in measurement results caused by leakage of the device when the sediments emit greenhouse gases.

[0007] In order to solve the above problems, the present application is implemented through the following technical solutions: A device for measuring greenhouse gases at the water-air interface during a water level drop comprises a columnar body, a scale is arranged on one side of the columnar body, a foam board is installed on the inner wall of the columnar body, the foam board is connected to a water pumping port, the water pumping port is connected to a TPU tube inlet, a detection outlet of the TPU tube is connected to a water pump inlet, one end of the water pump outlet is connected in parallel to a water quality analyzer and an inlet of a water-gas separation device, and a gas outlet of the water-gas separation device is connected to the gas analyzer.

[0008] The water pumping port is connected to a spirally telescopic and coiled tubular TPU tube to adapt to the height position adjustment of the water pumping port when the water level drops.

[0009] The inner wall of the column is connected with the outer wall of the foam board.

[0010] A counterweight is arranged on the foam plate, and the counterweight is connected to the water extraction port.

[0011] A retractable spring tube is provided at one end of the tail of the TPU tube.

[0012] One end of the atmospheric branch pipe of the TPU pipe is connected with a three-way valve.

[0013] The mass of the counterweight accounts for 10% to 12% of the displacement of the foam board.

[0014] The counterweight is made of stainless steel.

[0015] The method for using the device for measuring greenhouse gases at the water-air interface during water level drop comprises the following steps: S1, mix the sediment and put it into the acrylic column 3 and let it stand; S2, adding water to the upper surface of the sediment along the inner wall of the column 3 with a syringe; S3, placing the water extraction port 10 on the foam board in contact with the water surface; S4. Turn on the water pump 13 to pump water. When there are no bubbles in the water pipe, turn on the multi-parameter water quality analyzer 14, the water vapor separation device 15 and the greenhouse gas analyzer 17 to measure the concentration of CO2 and CH4 in the water, and synchronously time and measure the distance of water level drop.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention generates CO2 and CH4 through sediments, and uses a water pump to slowly pump water. A part of the water is used for real-time monitoring and determination of the physical and chemical properties of the water body, and a part of the water is measured by a water-gas separation device to measure CO2 and CH4, so that the water level drops evenly to reflect the CO2 and CH4 emissions from the water surface when the water level drops, thereby accurately evaluating the carbon emissions of the reservoir.

[0017] 2. The present invention can accurately and real-time reflect the response relationship between water level changes and greenhouse gas concentration at the water-air interface and time.

[0018] 3. The present invention can explore the relationship between the greenhouse gas concentration on the water surface and the specific water level drop value. Accurately quantify the water level drop distance and the corresponding water surface greenhouse gas concentration; 4. The present invention uses an acrylic device with regular shape and known size to facilitate the calculation of greenhouse gas fluxes on the water surface.

[0019] 5. The three-way valve provided in the present invention can prevent the water quality analyzer and the water-gas separation device from back-inhalation, and is convenient for exhaust, which is conducive to setting the water suction port close to the water surface to ensure the overall air tightness. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of a device for measuring sediment water level changes and greenhouse gas emissions according to the present invention.

[0021] Figure 2 It is a schematic diagram of the device for measuring sediment water level change and greenhouse gas emission after water injection according to the present invention.

[0022] Figure numerals: sediment 1, sediment-water interface 2, column 3, water body 4, scale 5, direction of water level drop 6, water surface 7, foam board 8, counterweight 9, water suction port 10, water flow direction 11, TPU tube 12, three-way valve 1201, spring tube 1202, atmospheric branch pipe 1203, water pump 13, water quality analyzer 14, water-gas separation device 15, air flow direction 16, gas analyzer 17. DETAILED DESCRIPTION

[0023] Example 1 like Figure 1~Figure 2 As shown, sediment 1, sediment-water interface 2, column 3 is a column of acrylic material with regular shape, filtered water 4, scale 5, water level drop direction 6, water surface 7, the outer diameter of the foam board 8 is slightly smaller than the inner diameter of the column of acrylic material with regular shape 3, counterweight 9, water suction port 10, water flow direction 11, TPU tube 12, water pump 13 is a water pump with fixed flow rate, water quality analyzer 14 is a multi-parameter water quality analyzer, water gas separation device 15, air flow direction 16, gas analyzer 17 is a greenhouse gas analyzer.

[0024] like Figure 1 The figure shows a device for measuring greenhouse gases at the water-air interface during the process of water level decline. Among them, the sediment 1 generates greenhouse gases, the sediment-water interface 2 is the interface where the greenhouse gases generated by the sediment enter the water body, the acrylic column 3 with regular shape is convenient for calculating the sediment and water volume and checking the distance of water level decline, the filtered water body 4 is the carrier for the transmission of greenhouse gases to the water surface, the scale 5 is used to accurately monitor the distance of water level decline, the water surface 7 is the interface where greenhouse gases enter the atmosphere, the foam board 8 is used to connect the water inlet 10 to prevent greenhouse gas leakage, the counterweight 9 makes the foam board 8 completely cover and contact the water surface 7, the TPU tube 12 is used to connect various devices to ensure that the water body and gas do not leak, the water pump 13 with a fixed flow rate is used to pump water, the multi-parameter water quality analyzer 14 is used to monitor the physical and chemical properties of the water body, and the combination of the water-gas separation device 15 and the greenhouse gas analyzer 17 is used to indirectly measure the greenhouse gas concentration on the water surface.

[0025] A device for measuring greenhouse gases at the water-air interface during a water level drop, comprising a columnar body 3, a scale 5 being provided on one side of the columnar body 3, a foam plate 8 being installed on the inner wall of the columnar body 3, the foam plate 8 being connected to a water pumping port 10, the water pumping port 10 being connected to an inlet of a TPU tube 12, a detection outlet of the TPU tube 12 being connected to an inlet of a water pump 13, one end of the outlet of the water pump 13 being connected in parallel to an inlet of a water quality analyzer 14 and a water-gas separation device 15, and a gas outlet of the water-gas separation device 15 being connected to a gas analyzer 17.

[0026] The water inlet 10 is connected to a spirally telescopic and coiled tubular TPU tube 12 to adapt to the height position adjustment of the water inlet 10 when the water level drops.

[0027] The inner wall of the columnar body 3 is in close contact with the outer wall of the foam board 8 .

[0028] A counterweight 9 is mounted on the foam plate 8 , and the counterweight 9 is connected to a water pumping port 10 .

[0029] A retractable spring tube 1202 is provided at one end of the tail of the TPU tube 12 .

[0030] One end of the atmospheric branch pipe 1203 of the TPU tube 12 is connected to a three-way valve 1201 .

[0031] The mass of the counterweight 9 accounts for 10% to 12% of the displacement of the foam board 8 .

[0032] The material of the counterweight 9 is stainless steel.

[0033] A method for using a device for measuring greenhouse gases at a water-air interface during a water level drop, comprising the following steps: S1, mix the sediment to be tested and put it into the acrylic column 3, and let it stand for 7 days; S2, adding water to the upper surface of the sediment along the inner wall of the column 3 with a syringe; S3, placing the water extraction port 10 on the foam board in contact with the water surface; S4. Turn on the water pump 13 to pump water. When there are no bubbles in the water pipe, turn on the multi-parameter water quality analyzer 14, the water vapor separation device 15 and the greenhouse gas analyzer 17 to measure the concentration of CO2 and CH4 in the water, and synchronously time and measure the distance of water level drop.

[0034] In the present invention, the height of the water body in the columnar body 3 is 1m~1.5m.

[0035] When the counterweight 9 is too heavy (greater than 12%), it is not conducive to the resetting of the spring tube 1202. When the counterweight 9 is too light, the water body cannot fit the water pumping port 10 and the foam board 8, resulting in the foam board 8 being suspended in the air on the inner wall of the column 3 when the water body drops during the measurement. When the foam board 8 is suspended in the air, the foam board 8 tilts downward and leaks sideways, causing air leakage.

[0036] A retractable spring tube 1202 is provided at one end of the tail of the TPU tube 12, so that the TPU tube 12 can be dropped along the surface of the water body and fit down to ensure air tightness during the measurement process. One end of the spring tube 1202 is connected to the suction port and the counterweight 9 so that the foam plate fits in contact with the water surface below, avoiding air leakage and making the measurement result more accurate. A three-way valve 1201 is connected to one end of the TPU tube 12; after the test is completed, the three-way valve 1201 is rotated to the atmospheric branch 1203 of the TPU tube 12 to connect to the atmosphere.

[0037] Preferably, the column 3 is purchased from Henan Shengyu Plastic Industry Co., Ltd., model: large acrylic column tube. The inner diameter of the column 3 is 490 mm. Preferably, the inner wall of the column 3 is made of acrylic material.

[0038] Preferably, the counterweight 9 is purchased from Shenzhen Kede Technology Co., Ltd., has a diameter of 200 mm, a thickness of 10 mm, and is made of stainless steel.

[0039] Preferably, the foam board 8 is purchased from Jiaozuo Xinlv Foam Board Co., Ltd., model: diameter 488mm, thickness 20mm.

[0040] Preferably, the TPU tube 12 is purchased from Shunping County Zhongxing Plastic Products Co., Ltd., made of TPU material, model: diameter 10 mm, thickness 2 mm.

[0041] Preferably, the water pump 13 is purchased from Grundfos Pumps (Suzhou) Co., Ltd., model: flow rate 0ml / min~2000ml / min.

[0042] Preferably, the multi-parameter water quality analyzer 14 is purchased from Xylem Inc. of the United States, and its model is YSI EXO.

[0043] Preferably, the gas analyzer 17 is purchased from Picarro Corporation of the United States, and its model is G2201-i greenhouse gas analyzer.

[0044] Preferably, the water pump 13, the water quality analyzer 14, the water-gas separation device 15 and the gas analyzer 17 are powered by an external power supply.

[0045] The present invention can be applied to the measurement of sludge sediments at the bottom of a reservoir, and can also be used for the detection of CO2 and CH4 in the decomposition process of other organic matter, with convenient detection and accurate data.

[0046] The device of the present invention can calculate the greenhouse gas flux change value to reflect its response relationship with the water level drop distance based on the greenhouse gas data concentration, the inner diameter size of the regularly shaped acrylic material column, the water level drop distance and the corresponding time data.

Claims

1. A device for measuring greenhouse gases at a water-air interface during a water level drop, comprising a columnar body (3), characterized in that: A scale (5) is provided on one side of the columnar body (3), and a foam plate (8) is provided on the inner wall of the columnar body (3), the foam plate (8) is connected to a water pumping port (10), the water pumping port (10) is connected to an inlet of a TPU tube (12), a detection outlet of the TPU tube (12) is connected to an inlet of a water pump (13), one end of the outlet of the water pump (13) is connected in parallel to an inlet of a water quality analyzer (14) and a water-gas separation device (15), and a gas outlet of the water-gas separation device (15) is connected to a gas analyzer (17).

2. The device for measuring greenhouse gases at the water-air interface during water level decline according to claim 1, characterized in that: The water pumping port (10) is connected to a spirally telescopic and coiled tubular TPU tube (12) to adapt to the height position adjustment of the water pumping port (10) when the water level drops.

3. The device for measuring greenhouse gases at the water-air interface during water level decline according to claim 1, characterized in that: The inner wall of the columnar body (3) is fitted and connected to the outer wall of the foam board (8).

4. The device for measuring greenhouse gases at the water-air interface during water level decline according to claim 1, characterized in that: A counterweight (9) is mounted on the foam plate (8), and the counterweight (9) is connected to the water extraction port (10).

5. The device for measuring greenhouse gases at the water-air interface during water level decline according to claim 1, characterized in that: A retractable spring tube (1202) is provided at one end of the tail of the TPU tube (12).

6. The device for measuring greenhouse gases at the water-air interface during water level decline according to claim 1, characterized in that: One end of the atmospheric branch pipe (1203) of the TPU tube (12) is connected to a three-way valve (1201).

7. The device for measuring greenhouse gases at the water-air interface during water level decline according to claim 4, characterized in that: The mass of the counterweight (9) accounts for 10% to 12% of the displacement of the foam plate (8).

8. The device for measuring greenhouse gases at the water-air interface during water level decline according to claim 4, characterized in that: The counterweight (9) is made of stainless steel.

9. A method for using the device for measuring greenhouse gases at the water-air interface during water level decline as claimed in claims 1 to 8, characterized in that: The steps include: S1, mix the sediment and put it into the acrylic column 3 and let it stand; S2, adding water to the upper surface of the sediment along the inner wall of the column 3 with a syringe; S3, placing the water extraction port 10 on the foam board in contact with the water surface; S4. Turn on the water pump 13 to pump water. When there are no bubbles in the water pipe, turn on the multi-parameter water quality analyzer 14, the water vapor separation device 15 and the greenhouse gas analyzer 17 to measure the concentration of CO2 and CH4 in the water, and synchronously time and measure the distance of water level drop.

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