Carbon capture sampling system for measuring atmospheric methane source according to carbon isotope ratio

Abstract

The invention discloses a carbon trapping and sampling system for measuring an atmospheric methane source according to a carbon isotope ratio. The system comprises a gas inlet module, an impurity removal module, a catalytic oxidation module, a methane derived carbon trapping module and a control module. The impurity removal module is connected to the rear end of the gas inlet module, the impurity removal module comprises a solid particulate matter removal assembly, a composite drying assembly, a CO removal assembly and a CO2 adsorption assembly, and the composite drying assembly adopts a replaceable composite drying agent and is provided with a visual window. The CO removal assembly is connected to the rear end of the composite drying assembly, and Hopcalite is adopted as a catalyst. After the catalytic oxidation module is connected to the impurity removal module, a tubular catalytic oxidation furnace is arranged, and a platinum catalyst is used for catalyzing methane oxidation. The system is simple in overall structure and convenient to operate, can be deployed and applied in various scenes, and can capture carbon in atmospheric methane at a sampling point without transporting a large number of air samples so as to measure the carbon isotope ratio.

Description

Technical Field

[0001] This invention relates to the field of atmospheric methane sampling and radiocarbon analysis technology, specifically to a carbon capture and sampling system suitable for determining the source of atmospheric methane using carbon isotope ratios. Background Technology

[0002] In recent years, global warming caused by the greenhouse effect has led to more frequent extreme weather events, melting glaciers, and rising sea levels. Excessive emissions of greenhouse gases have been the primary cause of the greenhouse effect since the mid-20th century, with anthropogenic emissions being the main source of new greenhouse gases. Methane, as the second most important anthropogenic greenhouse gas, makes the analysis of urban atmospheric methane sources crucial.

[0003] Traditional methods are bottom-up approaches based on emission inventories, calculating carbon emissions using statistical data on the consumption of various fossil fuels and carbon conversion factors (i.e., emission factors). Another approach is top-down, which uses atmospheric methane concentration (remote sensing and ground-based measurements) to invert greenhouse gas emissions, thus validating the results of the traditional bottom-up inventory. Research shows that the calculations based on the top-down approach are significantly higher than those based on source inventory statistics, potentially due to errors caused by emissions from natural sources such as wetlands. Therefore, it is necessary to employ a method independent of the bottom-up inventory approach to study the characteristics of urban fossil source carbon emissions and to cross-validate the two methods across temporal and spatial scales to improve the reliability of urban fossil source methane emission data. 14 C exists only in non-fossil fuels, and is not present in methane emissions from the combustion of fossil fuels. 14 C, then using the measured data, based on 14 The conservation of carbon (C) and methane mass allows for quantitative analysis of the contributions of fossil and non-fossil sources to atmospheric methane. However, since atmospheric methane content is much lower than that of carbon dioxide (only in the ppb range), traditional sampling methods require the collection of large quantities of gas.

[0004] In view of this, the development of an operational, replicable, low-cost, and long-term continuous atmospheric methane radiocarbon analysis sampling system has become an urgent need. Summary of the Invention

[0005] In view of the above-mentioned needs and the shortcomings of the prior art, the purpose of this invention is to provide a carbon capture sampling system for determining the source of atmospheric methane by carbon isotope ratio, so as to solve the problem of huge sampling volume in the existing route.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A carbon capture and sampling system for determining the source of atmospheric methane using carbon isotope ratio analysis is disclosed. The system includes an air intake module, an impurity removal module, a catalytic oxidation module, a methane-derived carbon capture module, and a control module. The air intake module is sequentially connected to the impurity removal module, the catalytic oxidation module, and the methane-derived carbon capture module via pipelines. The control module is electrically connected to each module to regulate the sampling process.

[0007] In the carbon capture sampling system for determining the source of atmospheric methane by carbon isotope ratio determination, the air intake module includes a three-way valve and a vacuum pump. The outlet 1 of the three-way valve is connected to the impurity removal module, the outlet 2 of the three-way valve is connected to the vacuum pump, and the inlet of the three-way valve is connected to the sampling gas inlet.

[0008] In the carbon capture sampling system for determining the source of atmospheric methane using carbon isotope ratios, the impurity removal module includes a solid particulate matter removal component, a composite drying component, a CO removal component, and a CO2 adsorption component. The solid particulate matter removal component is sequentially connected to the composite drying component, the CO removal component, and the CO2 adsorption component. It is used to remove solid particulate matter, H2O, CO, and CO2 from the sampled air.

[0009] In the carbon capture sampling system for determining the source of atmospheric methane by carbon isotope ratio determination, the impurity removal module uses a replaceable composite desiccant in the composite drying component and is equipped with a visualization window. The replaceable composite desiccant consists of 13x molecular sieve desiccant and color-changing silica gel desiccant. The color-changing silica gel desiccant is placed inside the visualization window, and the 13x molecular sieve desiccant is placed inside the molecular sieve barrel. The visualization window is a transparent quartz tube with an outer diameter of 20 mm.

[0010] In the carbon capture sampling system for determining the source of atmospheric methane by carbon isotope ratio determination, the CO removal component in the impurity removal module includes a 3 / 8-inch U-shaped 316L stainless steel tube filled with hogalat as a catalyst.

[0011] In the carbon capture sampling system for determining the source of atmospheric methane by carbon isotope ratio determination, the CO2 adsorption component in the impurity removal module comprises a 3 / 8-inch U-shaped 316L stainless steel tube filled with 13x molecular sieve.

[0012] In the carbon capture and sampling system for determining the source of atmospheric methane by carbon isotope ratio determination, the catalytic oxidation module is equipped with a tubular catalytic oxidation furnace, which is covered with a 3 / 8-inch outer diameter 316L stainless steel tube, filled with a platinum-containing catalyst, supported by alumina, and the temperature is controlled at 650-700℃.

[0013] In the carbon capture sampling system for determining the source of atmospheric methane by carbon isotope ratio determination, the methane-derived carbon capture module includes a drying component, a carbon capture component, and a heating furnace. The drying component uses a quartz tube with an outer diameter of 20 mm and is filled with magnesium perchlorate.

[0014] In the carbon capture sampling system for determining the source of atmospheric methane for carbon isotope ratio determination, the methane-derived carbon capture module includes a three-way valve and a 1 / 4-inch U-shaped 316L stainless steel tube, forming a closed loop. The tube is filled with 60-80 mesh 13x molecular sieve and is a detachable loop. The carbon capture module is connected to the pipeline through a quick-release sealing connector, which facilitates disassembly and testing after sampling and replacement of the filler.

[0015] In the carbon capture sampling system for determining the source of atmospheric methane by carbon isotope ratio determination, the methane-derived carbon capture module includes an open-type tubular furnace in which the lower part of the carbon capture component can be inserted into the heating area inside the furnace, and the heating temperature is controlled between 250℃ and 650℃.

[0016] Compared to existing technologies, this invention provides a carbon capture sampling system for determining the source of atmospheric methane in carbon isotope ratio measurements. It meets the requirements for radioactive carbon isotope ratio determination without requiring large-scale air sampling. The core components utilize readily available and stable-supply reliable products and consumables. It boasts long-term sampling capabilities; the amount of desiccant in the composite drying component of the impurity removal module can be adjusted according to the sampling duration to meet the required sampling time. Precise control via the control module enables continuous sampling for over 24 / 7 without interruption for maintenance. The carbon capture component in the methane-derived carbon capture module can be regenerated in situ, allowing for repeated testing and background pretreatment. The system is simple to install and disassemble, with convenient maintenance procedures, requiring no specialized imported equipment, and is adaptable to various laboratory monitoring and sampling scenarios. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the carbon capture and sampling system for determining the source of atmospheric methane using carbon isotope ratios, provided by the present invention.

[0018] Figure 2 This is a system block diagram of a carbon capture and sampling system for determining the source of atmospheric methane using carbon isotope ratios, provided by the present invention.

[0019] Figure 3 This is a schematic diagram of the carbon capture component structure of the carbon capture sampling system for determining the source of atmospheric methane using carbon isotope ratios, provided by the present invention.

[0020] Attached icon number 11. Three-way valve; 12. Vacuum pump; 21. Solid particulate matter removal assembly; 22. Composite drying assembly; 23. CO removal assembly; 24. CO2 adsorption assembly; 31. Tubular catalytic oxidation furnace; 41. Drying assembly; 42. Carbon capture assembly; 43. Heating furnace; 51. Flow controller; 52. Vacuum pump; 53. Pressure transmitter; 54. PLC integrated machine; 55. Flow meter. Detailed Implementation

[0021] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0022] It should be noted that when a module or component is referred to as being "mounted on," "fixed to," or "set on" another module or component, it can be directly on the other module or component, or there may be an intervening component or part present. When a module or component is referred to as being "connected to" another module or component, it can be directly connected to the other module or component, or there may be an intervening component or part present.

[0023] It should also be noted that the directional terms such as left, right, up, and down in the embodiments of the present invention are only relative concepts or are based on the normal use state of the product, and should not be considered as restrictive.

[0024] This invention provides a carbon capture and sampling system for determining the source of atmospheric methane using carbon isotope ratios, comprising an air intake module, an impurity removal module, a catalytic oxidation module, a methane-derived carbon capture module, and a control module. The modules are not necessarily a continuous whole, but rather functionally differentiated modules. Individual modules may contain pipes and fittings such as valves and connectors, and may also include intermediate components or assemblies. The same component may exist in different modules.

[0025] Please refer to the following: Figure 1 and Figure 2 The air intake module includes a three-way valve 11 and a vacuum pump 12. The impurity removal module includes a solid particulate matter removal component 21, a composite drying component 22, a molecular sieve barrel component 221, a transparent quartz drying component 222, a CO removal component 23, and a CO2 adsorption component 24. The catalytic oxidation module includes a tubular catalytic oxidation furnace 31. The methane-derived carbon capture module includes a drying component 41, a carbon capture component 42, and a heating furnace 43. The control module includes a vacuum pump 12, a flow controller 51, a vacuum pump 52, a pressure transmitter 53, a PLC integrated machine 54, and a flow meter 55.

[0026] The three-way valve 11 and vacuum pump 12 constitute an air intake module. The outlet 1 of the three-way valve 11 is connected to the solid particulate matter removal component 21 in the impurity removal module. The outlet 2 of the three-way valve 11 is connected to the vacuum pump 12. The inlet of the three-way valve 11 is the sampling gas path inlet. In this embodiment, the vacuum pump 12 is used to deal with the possibility that the sampling gas path inlet has a long gas path connected to the outdoors, in order to empty the long deposited gas path and remove the background.

[0027] In this embodiment, multiple reference gas and purge gas inlets and multiple sampling points can be optionally added, such as between the three-way valve 11 and the particulate matter removal component 21, and between the flow meter 55 and the vacuum pump 52. Adding or removing inlet / outlet ports at these locations is to meet actual usage needs and should not be considered restrictive. The gas path connected to the three-way valve, controlled by a switching valve, is normally closed and does not affect actual sampling. It includes four gas paths: the first two can be used to purge the system to remove background noise, and can be used to introduce reference gases of different configuration ratios for other possible tests, efficiency tests, blank tests, etc. The latter two are also optional sampling interfaces used to test system efficiency, capacity, etc. These are all optional and can be changed, added, or removed according to actual needs without affecting the system's methane sampling function.

[0028] The solid particulate matter removal component 21 is connected to the air intake module. In this example, a sintered metal filter with a filtration accuracy of 5 μm is used. Similarly, the type and filtration accuracy of the filter should not be considered limiting.

[0029] The composite drying component 22, connected to the solid particulate removal component 21, includes a molecular sieve barrel component 221 and a transparent quartz drying component 222. The molecular sieve barrel component 221 consists of a molecular sieve barrel and a built-in desiccant. The molecular sieve barrel is a commercially available product component, commonly used inside hydrogen and oxygen production equipment. In this embodiment, the molecular sieve barrel component 221 contains 13x molecular sieve desiccant, with a dosage of 0.7-0.8 kg. It is regenerable and reusable, and the dosage of 13x molecular sieve desiccant can be set according to the sampling time, meeting the requirements of low cost, operability, and convenient replacement and regeneration. The transparent quartz drying component 222 consists of a transparent quartz tube, a connector, and a built-in color-changing silica gel desiccant. The transparent quartz tube provides a visualization window, and by observing the color of the color-changing silica gel desiccant, it is possible to intuitively detect whether the system's drying performance has failed. In this embodiment, a transparent quartz tube with a length of 200 mm and an outer diameter of 20 mm is used. The built-in color-changing silica gel desiccant is a common commercial product and is also a regenerable desiccant. In this embodiment, the dosage of the color-changing silica gel desiccant is 50 g. Understandably, the desiccant in the 22-piece composite drying unit can be replaced, for example, with 3A molecular sieve.

[0030] Please see Figure 2The CO removal component 23 is connected to the composite drying component 22. In this embodiment, more specifically, the vacuum pump 52 is placed between the composite drying component 22 and the CO removal component 23. The CO removal component 23 consists of a 3 / 8-inch outer diameter U-shaped 316L stainless steel tube filled with hogalat as a catalyst. The bend length of the 3 / 8-inch outer diameter U-shaped 316L stainless steel tube is approximately 40 cm to meet the required amount of hogalat catalyst. In this embodiment, the amount of hogalat is 40 g. Because hogalat is sensitive to humidity, the CO removal component 23 should be placed after the composite drying component 22. Furthermore, the CO2 adsorption component 24 is connected to the CO removal component 23. In this embodiment, the CO2 adsorption component 24 comprises three sections of 3 / 8-inch outer diameter U-shaped 316L stainless steel tubes, each approximately 40cm in length. These sections are connected in series with other 3 / 8-inch outer diameter 316L stainless steel tubes via connectors. Each section is filled with 20g of 13x molecular sieve, primarily for adsorbing and removing CO2, as well as some H2O that may escape from the front-end composite drying component 22. With this, the impurity removal module is fully functional. In this application, through the processing of the above modules, solid particles, H2O, CO, and CO2 in the sampled gas entering through the inlet module can be removed. The carbon source in the remaining gas can be considered to be methane from the atmosphere.

[0031] Furthermore, the catalytic oxidation module will be connected after the impurity removal module; please refer to [further details]. Figure 2 After the tubular catalytic oxidation furnace 31 is connected to the CO2 adsorption component 24, in this embodiment, the catalytic oxidation module mainly includes the tubular catalytic oxidation furnace 31, which is covered with a 3 / 8-inch outer diameter 316L stainless steel tube, and the internal pipeline is filled with platinum catalyst and alumina support, with a dosage of 1-2g. The tubular catalytic oxidation furnace 31 can control the temperature at 650-700℃ to catalyze the oxidation of methane to produce H2O and CO2.

[0032] Furthermore, after the methane-derived carbon capture module is connected to the catalytic oxidation module, please refer to [further details]. Figure 2 The drying component 41 is connected to the tubular catalytic oxidation furnace 31 to remove H2O generated after methane oxidation. The drying component 41 consists of a quartz tube with an outer diameter of 20 mm and a length of 200 mm, filled with magnesium perchlorate. In this embodiment, 50 g of magnesium perchlorate is used. Using magnesium perchlorate as a desiccant removes only the H2O generated by methane oxidation without affecting the amount of carbon derived from methane.

[0033] After the carbon capture assembly 42 is connected to the drying assembly 41, please refer to [link / reference needed]. Figure 3The carbon capture assembly 42 includes two three-way valves and two sections of 1 / 4-inch outer diameter U-shaped 316L stainless steel tubing, forming a closed loop. It is internally filled with 13x molecular sieve. In this embodiment, the longer section of the U-shaped bend is 40-45 cm long. The entire loop is detachable, and the carbon capture assembly 42 is connected to the pipeline via quick-release sealing connectors, facilitating disassembly for testing and replacement of the filling material after sampling. Furthermore, by rotating the two three-way valves to change the connection direction, the carbon capture assembly 42 can be connected to the upstream and downstream pipelines, or optionally, the carbon capture assembly 42 itself can be closed. In this embodiment, the internal filling material is 60-80 mesh molecular sieve, used in 2g increments.

[0034] The heating furnace 43 is an open-type tubular furnace. The lower U-shaped portion of the carbon capture assembly 42 extends approximately 10-15 cm into the heating area within the furnace, and the heating temperature can be controlled between 250℃ and 650℃. By heating the lower U-shaped portion of the carbon capture assembly 42 through the heating furnace 43, the molecular sieve inside the carbon capture assembly 42 can be heated for regeneration and pre-treated before sampling to reduce or remove background carbon, thus ensuring sampling accuracy.

[0035] Please continue reading. Figure 2 The flow controller 51 is located between the CO2 adsorption component 24 and the tubular catalytic oxidation furnace 31, and the flow meter 55 is located after the carbon capture component 42. The flow controller 51 can be set to a flow rate range of 300 cc / min to 450 cc / min, and the flow meter 55 can be set to a flow rate of 300 cc / min. Through the flow difference, the gas pressure between them can be increased to 2.7 bar (gauge pressure). The pressure transmitter 53 is located between the drying component 41 and the carbon capture component 42 to monitor the sampling gas pressure in this flow section.

[0036] Two vacuum pumps 52 are provided, one positioned between the composite drying assembly 22 and the CO removal assembly 23, and the other downstream of the flow meter 55. In this embodiment, the vacuum pump 52 samples a flow rate of 5.5 L / min to provide the gas flow power in the system's gas path.

[0037] The control module includes a vacuum pump 12, a flow controller 51, a vacuum pump 52, a pressure transmitter 53, a PLC integrated unit 54, and a flow meter 55. The vacuum pump 52 provides sampling power, the flow rate of the flow controller 51 and the flow meter 55 is set to control the sampling pressure, and the sampling pressure is monitored by receiving signals from the pressure transmitter 53, thereby enabling regulation and alarm functions. All system settings and operations are performed on the PLC integrated unit 54.

[0038] The carbon capture sampling system for determining the source of atmospheric methane using carbon isotope ratios should undergo pretreatment before actual sampling. First, all molecular sieves and desiccants should be heated at 700°C for at least 3 hours to remove adsorbed impurities and moisture before being loaded into their respective components.

[0039] For further details, please refer to Figure 2 The three-way valve 11 is kept closed at all times. High-purity nitrogen is used to purge the system pipeline through the purge gas inlet (not shown in the figure) between the three-way valve 11 and the solid particulate matter removal component 21 to reduce the background pressure. During purging, the pressure transmitter 53 should monitor a stable pressure between 2.7 ± 0.5 bar, which is achieved by setting the flow rate of the flow controller 51 to 450 cc / min and the flow rate of the flow meter 55 to 300 cc / min. After the pressure stabilizes, the flow rate of the flow controller 51 is adjusted to 300 cc / min to maintain the pressure. Simultaneously, the heating furnace 43 is heated to 550°C, and purging is continued for 2 hours.

[0040] Furthermore, please refer to [the relevant documentation] before formal sampling. Figure 2 The three-way valve 11 should be opened to the direction from outlet 2 to vacuum pump 12. The pipeline between the system inlet (not marked in the figure) and the sampling inlet (not marked in the figure) should be purged with sampling gas for 5 minutes to ensure that the actual sampled gas is the target gas. This design is intended to meet actual usage requirements. If there is no sampling pipeline, this component and purging process are not limited, and therefore should not be considered restrictive.

[0041] In summary, the present invention provides a carbon capture sampling system for determining the source of atmospheric methane for carbon isotope ratio determination, comprising an air intake module, an impurity removal module, a catalytic oxidation module, a methane-derived carbon capture module, and a control module. It meets the requirements of operability, reproducibility, low cost, and long-term continuous sampling. Compared with traditional sampling methods, it can capture carbon from atmospheric methane at the sampling point without transporting a large number of air samples, and then perform carbon isotope ratio determination.

[0042] It is understood that those skilled in the art can make equivalent substitutions or modifications to the technical solution and inventive concept of the present invention, and all such substitutions or modifications should fall within the protection scope of the appended claims.

Claims

1. A carbon capture sampling system for carbon isotope ratio determination of atmospheric methane sources, characterized by, The system comprises an air inlet module, an impurity removal module, a catalytic oxidation module, a methane-derived carbon capture module and a control module. The impurity removal module comprises a solid particle removal assembly, a composite drying assembly, a CO removal assembly and a CO2 adsorption assembly, which are used to remove solid particles, H2O, CO and CO2 in the sampling air. The catalytic oxidation module is provided with a tubular catalytic oxidation furnace, and a platinum catalyst is built in the pipeline to catalyze the oxidation of methane. The methane-derived carbon capture module comprises a drying assembly, a carbon capture assembly and a heating furnace, the carbon capture assembly is a detachable long-acting structure, and is used to capture the derived carbon after the catalytic oxidation of methane. The control module comprises a mass flow meter, a vacuum pump, a pressure transmitter and a PLC all-in-one machine, which are used to control the start and stop of the system, control and monitor the sampling flow, and support the stable and long-time operation of the system.

2. The carbon capture sampling system for carbon isotope ratio determination of atmospheric methane sources according to claim 1, wherein, The impurity removal module comprises a solid particle removal assembly, a composite drying assembly, a CO removal assembly and a CO2 adsorption assembly, which are used to remove solid particles, H2O, CO and CO2 in the sampling air.

3. The carbon capture sampling system for carbon isotope ratio determination of atmospheric methane sources of claim 2, wherein, The composite drying assembly uses replaceable composite drying agent, and is provided with a visual window, the replaceable composite drying agent is composed of 13x molecular sieve drying agent and color-changing silica gel drying agent, and 50g of the color-changing silica gel drying agent is arranged at the visual window.

4. The carbon capture sampling system for carbon isotope ratio determination of atmospheric methane sources of claim 3, wherein, The CO removal assembly comprises a 3 / 8-inch U-shaped 316L stainless steel pipe with a bend length of 40-45 cm, which is internally filled with a catalyst with a dosage of 40g.

5. The carbon capture sampling system for carbon isotope ratio determination of atmospheric methane sources of claim 3, wherein, The CO2 adsorption assembly comprises a 3 / 8-inch U-shaped 316L stainless steel pipe with a bend length of 40-45 cm, which is filled with 13x molecular sieve with a dosage of 60g.

6. The carbon capture sampling system for carbon isotope ratio determination of atmospheric methane sources of claim 1, wherein, The catalytic oxidation module is provided with a tubular catalytic oxidation furnace, which is coated with a 3 / 8-inch 316L stainless steel pipe, internally filled with a platinum-containing catalyst, and the carrier is alumina with a dosage of 1-2g, and the temperature is controlled at 650-700℃.

7. The carbon capture sampling system for carbon isotope ratio determination of atmospheric methane sources of claim 1, wherein, The methane-derived carbon capture module is provided with a drying assembly, a carbon capture assembly and a heating furnace, the drying assembly uses a 20mm outer diameter quartz tube with a length of 200mm, which is internally filled with magnesium perchlorate.

8. The carbon capture sampling system for carbon isotope ratio determination of atmospheric methane sources of claim 7, wherein, The heating furnace is an open tubular furnace, which can heat the lower part of the carbon capture assembly of claim 9 to the heating area inside the furnace body.

9. The carbon capture sampling system for carbon isotope ratio determination of atmospheric methane sources of claim 1, wherein, The control module comprises a mass flow meter, a vacuum pump, a pressure transmitter, a PLC all-in-one machine and the like, which receives sensing signals through PLC, controls and monitors the sampling flow, and stabilizes the sampling flow at 300cc / min.

10. The carbon capture sampling system for carbon isotope ratio determination of atmospheric methane sources of claim 1, wherein, The system does not explicitly use a 1 / 4-inch 316L stainless steel pipe as the pipeline, and uses a clamping sleeve type sealing joint for pipeline connection, the vacuum pump and the air path in the system are communicated by using a thick rubber pipe, and a pagoda joint is used for the joint.

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