阅读说明：本技术 一种便携式的甲烷微量泄漏量化检测仪及其检测方法 (Portable methane trace leakage quantitative detector and detection method thereof ) 是由 董建锴 金瑞颖 王颖凡 杨硕 杜晓莉 于 2020-12-21 设计创作，主要内容包括：本发明提出一种便携式的甲烷微量泄漏量化检测仪及其检测方法,该检测仪包括气体收集与流动装置、甲烷浓度检测装置和空气流量检测装置,气体收集与流动装置上设置有甲烷浓度检测装置和空气流量检测装置；气体收集与流动装置包括依次连接的检测部位密封袋、进气软管、直流管道风机和出气口,检测部位密封袋包裹在管道测试点处。解决上述背景技术中提到的对于燃气管网的管道和其他设备和组件的泄漏需要一种便携式的甲烷微量泄漏量化检测仪的技术问题,提出一种便携式的甲烷微量泄漏量化检测仪及其检测方法,用于检测燃气输配管网末端各管道及其他装置设备的甲烷泄漏量。(The invention provides a portable methane trace leakage quantitative detector and a detection method thereof, wherein the detector comprises a gas collecting and flowing device, a methane concentration detection device and an air flow detection device, wherein the gas collecting and flowing device is provided with the methane concentration detection device and the air flow detection device; the gas collecting and flowing device comprises a detection part sealing bag, an air inlet hose, a direct-current pipeline fan and an air outlet which are sequentially connected, and the detection part sealing bag is wrapped at a pipeline testing point. The portable methane trace leakage quantitative detector and the detection method thereof are provided for detecting the methane leakage amount of each pipeline at the tail end of a gas transmission and distribution pipeline network and other equipment and devices.)

1. A portable methane trace leakage quantitative detector is characterized by comprising a gas collecting and flowing device, a methane concentration detection device and an air flow detection device, wherein the gas collecting and flowing device is provided with the methane concentration detection device and the air flow detection device; the gas collection and flow device comprises a detection part sealing bag (9), an air inlet hose (8), a direct-current pipeline fan (6) and an air outlet (4) which are sequentially connected, wherein the detection part sealing bag (9) is wrapped at a pipeline test point.

2. The portable quantitative detector for trace leakage of methane as claimed in claim 1, wherein the air inlet hose (8) is made of PVC, which is beneficial to gas circulation and convenient for manual operation and folding carrying.

3. The portable methane minimal quantity leakage quantitative detector according to claim 1, wherein the air flow detection device comprises a flow meter (3) for measuring the gas mass flow.

4. The portable methane micro-leakage quantitative detector according to claim 3, wherein the flow meter (3) is a thermal mass flow meter, and the detection of the natural gas quality is realized through the heat exchange between the fluid and the heat source.

5. The portable methane micro-leakage quantitative detector according to claim 1, wherein the methane concentration detection device comprises a probe type methane concentration detector, and a detector probe is positioned in the air inlet hose (8).

6. The portable quantitative detector for trace leakage of methane as claimed in claim 1, wherein the methane concentration detection device comprises two probe-type methane concentration detectors with different measurement concentration ranges, and the two ranges of methane concentration can be measured for regions with different leakage degrees.

7. The portable quantitative detector for trace leakage of methane as claimed in claim 1, wherein said portable quantitative detector for trace leakage of methane is contained in a backpack for easy carrying by an operator.

8. The portable quantitative detector for trace leakage of methane as claimed in claim 8, wherein the portable quantitative detector for trace leakage of methane employs a dc power supply, and the storage battery is located at the lower part of the backpack, and when fully charged, the device can continuously operate for more than 8 hours.

9. An inspection method using the portable methane micro-leakage quantitative detector according to any one of claims 1 to 8, comprising the following steps:

(1) in the testing process, the environment of a testing place needs to be observed to preliminarily judge whether the experimental environment meets the requirements, and the level of the methane concentration detector (2) needs to be corrected by using a level ruler (5);

(2) then selecting a natural gas pipeline riser, an elbow or a valve test point, taking out an air inlet hose (8), wrapping the test part by using a test part sealing bag (9), opening a direct-current pipeline fan (6), enabling the test part sealing bag (9) to be in a micro negative pressure state, enabling the direct-current pipeline fan (6) to play a role in extracting and mixing trace methane leaked from the test part with outside air, starting to record the readings of corresponding methane concentration detectors when the readings of a thermal mass flowmeter tend to be stable, adopting a methane concentration detector with a larger measurement concentration range in the test process, and replacing the methane concentration detector with another methane concentration detector with a smaller measurement concentration range if the displayed concentration is smaller;

(3) and finally, after effective data are read, the direct current pipeline fan (6) is closed, the detection part sealing bag (9) is taken down, the air inlet hose (8) is collected, and the test is finished.

10. The portable apparatus for detecting methane trace amount according to claim 9, wherein the apparatus for detecting methane concentration employs a semiconductor sensor detection method, which is based on the principle that when methane gas exists, the metal oxide of the semiconductor sensor inside the apparatus for detecting methane concentration (2) forces the gas molecules to dissociate into band-point ions, which causes electron transfer, and the characteristics reflected by the interaction of the sensing gas are measured by the bias electrode to obtain the methane concentration, and the apparatus for detecting methane concentration has a heating element therein, which can heat the sensor to the optimal temperature required for detecting the gas and keep it constant.

Technical Field

The invention relates to a portable methane trace leakage quantitative detector and a detection method thereof, in particular to a small leakage point of a pipeline valve, and belongs to the technical field of methane leakage detectors.

Background

Methane is a hydrocarbon and is the major constituent of Natural Gas (NG). Methane is becoming increasingly important as a greenhouse gas (GHG), not only because of its global warming potential, but also because of its higher and higher content in the atmosphere.

The use of natural gas has increased dramatically due to advances in technology and the growing interest in natural gas as an alternative fuel source for coal and petroleum. Methane is a short-lived, strong greenhouse gas with a rapid warming effect, and although its lifetime in the atmosphere is only 12 years, its Global Warming Potential (GWP) on the 20-year scale is 84 times that of carbon dioxide and 28 times that of carbon dioxide on the 100-year scale. A number of calculations were performed by Alvarez et al based on the various potential values of methane, and it was found that greenhouse gas emissions of methane relative to other fossil fuels were ignored when the leakage rate of natural gas was 1% to 5%. Transient, i.e., evanescent, emissions pose a threat to the environment due to the global warming potential of methane and the increased demand for methane. Therefore, efforts to reduce the methane emission energy have a beneficial effect on environmental and economic aspects.

At present, China still stays in rapid qualitative analysis and positioning research on natural gas leakage, and the flowmeters at all gate stations and all main pipelines are used as main leakage detection modes, most of the natural gas leakage detection modes are leakage caused by pipeline breakage or gas accidents, and deep research on tiny methane leakage amount of tiny openings in pipelines or leakage points at flanges and valves is not carried out. However, the natural gas is accompanied by methane emission in the stages of exploitation, transportation and use, the methane leakage amount at the tail end of the natural gas transmission and distribution system is not negligible, and the total leakage amount of the natural gas in the whole life cycle can be counted only by clearly knowing the methane emission amount at the upper, middle and lower reaches of the natural gas transmission and distribution, so that better supervision and maintenance can be carried out. Also, the uncertainty range of the leak estimation in the natural gas chain makes it difficult to determine whether natural gas will serve as a transition fuel to reduce the carbon economy. Reliable data is therefore crucial to understanding the role of natural gas in future energy production. The acquisition of the methane leakage data of pipelines and equipment of a downstream gas system is still blank in China, the influence of one or more methane micro-leakage is possibly very little, but the quantitative change can cause qualitative change, so the significance of measuring the methane micro-leakage is great.

According to the analysis, a portable methane trace leakage quantitative detector is needed for leakage of pipelines, other equipment and components of a gas pipe network, so that most of emission of the leaked components can be conveniently captured at each position of the gas pipe network, and the methane leakage emission amount can be accurately quantified.

Disclosure of Invention

The invention aims to solve the technical problem that a portable methane trace leakage quantitative detector is needed for the leakage of pipelines, other equipment and components of a gas pipe network in the background art, and provides the portable methane trace leakage quantitative detector and the detection method thereof, which are used for detecting the methane leakage of each pipeline and other equipment at the tail end of the gas transmission and distribution pipe network.

The invention provides a portable methane trace leakage quantitative detector which comprises a gas collecting and flowing device, a methane concentration detection device and an air flow detection device, wherein the gas collecting and flowing device is provided with the methane concentration detection device and the air flow detection device; the gas collecting and flowing device comprises a detection part sealing bag, an air inlet hose, a direct-current pipeline fan and an air outlet which are sequentially connected, wherein the detection part sealing bag is wrapped at a pipeline testing point.

Preferably, the air inlet hose is made of PVC pipes, so that on one hand, the air circulation is facilitated, and on the other hand, the manual operation and folding carrying are facilitated.

Preferably, the air flow detection means comprises a flow meter for measurement of the gas mass flow.

Preferably, the flow meter is a thermal mass flow meter which detects the quality of the natural gas by exchanging heat between the fluid and the heat source.

Preferably, the methane concentration detection device comprises a probe type methane detector, and a detector probe is positioned in the air inlet pipeline 8.

Preferably, the methane concentration detection device comprises two probe type methane detectors with different measurement concentration ranges, and the two ranges of methane concentration can be measured aiming at areas with different leakage degrees.

Preferably, the portable methane micro-leakage quantitative detector is arranged in a backpack, so that the portable methane micro-leakage quantitative detector is convenient for operators to carry.

Preferably, the portable methane trace leakage quantitative detector adopts a direct current power supply, the storage battery is positioned at the lower part of the backpack, and the full charge can enable the equipment to continuously work for more than 8 hours.

A method for checking the portable methane trace leakage quantitative detector specifically comprises the following steps:

(1) in the testing process, attention is paid to observing the environment of a testing place to preliminarily judge whether the experimental environment meets the requirements, and a leveling rule is required to correct the methane concentration detector;

(2) then selecting a natural gas pipeline vertical pipe, an elbow or a valve test point, taking out an air inlet hose, wrapping a test part by using a test part sealing bag, opening a fan to enable the test part sealing bag to be in a micro negative pressure state, wherein the fan plays a role in extracting and mixing trace methane leaked from the test part with outside air, when the reading of a thermal mass flowmeter tends to be stable, starting to record the reading of a corresponding methane concentration detector, adopting a methane concentration detector with a larger measurement concentration range in the test process, and replacing the methane concentration detector with another methane concentration detector with a smaller measurement concentration range if the displayed concentration is smaller;

(3) and finally, after the effective data is read, the fan is closed, the detection part sealing bag is taken down, and the air inlet hose is retracted, so that the test is finished.

Preferably, the methane concentration detection device adopts a semiconductor sensor detection method, and the principle is that when methane gas exists, the metal oxide of the semiconductor sensor in the methane concentration detection device forces gas molecules to be dissociated into band point ions to initiate electron transfer, the bias electrode is used for detecting different characteristics reflected by the interaction of the sensing gas to obtain the methane concentration, and the heating element is arranged in the methane concentration detection device, so that the sensor can be heated to the optimal temperature required by the detection gas and can be kept constant.

The portable methane trace leakage quantitative detector and the detection method thereof have the beneficial effects that:

(1) portability: the whole set of device is completely arranged in a backpack, so that the scale and the quality of the device are reduced, and meanwhile, the device is convenient for operators to carry and is beneficial to detecting small leakage points of a pipe network;

(2) high precision: the methane concentration detector adopts two probe type methane detectors with high precision and different measurement concentration ranges, uses an advanced semiconductor sensor detection method, and has higher reaction speed and higher sensitivity compared with the traditional catalytic combustion detection method; compared with the traditional flowmeter, the thermal flowmeter has larger measuring range, can measure the gas with the flow velocity lower than 0.5m/s, has good anti-seismic performance, is not influenced by vibration to the measurement precision, does not need temperature and pressure compensation for gas flow detection, and is convenient and accurate to measure;

(3) the maintenance is simple: compared with other detectors, the probe type methane detector does not need to use multiple sensing elements at the same time, only needs gas to be adsorbed on the sensor during working, and almost has no loss to the sensor; the sensor of the thermal flowmeter has no movable part and pressure sensing part, so the loss is small; in addition, the device is convenient to disassemble integrally, and can be quickly replaced even if the instrument is damaged in the operation process;

(4) the working time is long: each detection instrument is powered by a direct-current power supply storage battery, can continuously work for more than eight hours after being fully charged once, and can detect a pipeline of 10km a day by an operator.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention.

In the drawings:

FIG. 1 is a schematic structural diagram of a portable quantitative detector for trace leakage of methane according to the present invention;

the method comprises the following steps of 1, a detected air inlet, 2, a methane concentration detector, 3, a flowmeter, 4, an air outlet, 5, a backpack, 6, a direct-current pipeline fan, 7, a horizontal ruler, 8, an air inlet hose and 9, and a detection part sealing bag.

Detailed Description

The following detailed description of embodiments of the invention is provided in conjunction with the appended drawings:

the first embodiment is as follows: the present embodiment is explained with reference to fig. 1. The portable methane trace leakage quantitative detector comprises a gas collecting and flowing device, a methane concentration detection device and an air flow detection device, wherein the gas collecting and flowing device is provided with the methane concentration detection device and the air flow detection device; the gas collecting and flowing device comprises a detection part sealing bag 9, an air inlet hose 8, a direct current pipeline fan 6 and an air outlet 4 which are sequentially connected, wherein the detection part sealing bag 9 is wrapped at a pipeline testing point.

The air inlet hose 8 is made of PVC pipes, so that on one hand, gas circulation is facilitated, and on the other hand, manual operation and folding carrying are facilitated.

The methane concentration detection device mainly comprises two probe type methane concentration detectors 2 with different concentration measurement ranges, wherein a probe is positioned on an air inlet hose 8, and a semiconductor sensor detection method is mainly adopted. The device can be used for measuring the methane concentration in two ranges aiming at areas with different leakage degrees, and has higher measurement precision and stronger stability

The detection part sealing bag 9 can separate air outside the leakage point through the part of the device, and leaked fuel gas is guided into the air inlet hose 8 and flows out of the air outlet 5.

The direct current pipeline fan 6 operates at a lower wind speed to play a role in emptying the original air and guiding the leaked natural gas.

The air flow monitoring device mainly comprises a thermal mass flow meter 3, the thermal mass flow meter 3 is mainly used for measuring the mass flow of gas by exchanging heat between fluid and a heat source, almost no pressure loss exists, the mass flow of methane leaked by a leakage point in unit time can be obtained after post data processing, and meanwhile, a horizontal ruler 7 is placed in the instrument for auxiliary judgment for ensuring the measurement of flow under the horizontal working condition.

All equipment of this instrument all packs into a knapsack, and the operating personnel of being convenient for hand-carries, and all equipment all adopt DC power supply simultaneously, and the battery is located the knapsack lower part, and full charge can make equipment continuous operation more than 8 hours, and operating personnel can hand display, and real-time supervision methane concentration to judge at any time whether correct of detection procedure, whether the testing result is effective.

The invention discloses a portable methane trace leakage quantitative detector, which is characterized in that: (1) detecting the trace methane leakage of natural gas system pipelines and other equipment and components; (2) the portable multifunctional electric heating cooker is convenient for workers to carry and operate; (3) the detection precision can be increased, and therefore a large amount of reliable natural gas leakage data can be obtained.

The specific operation process of the portable methane trace leakage quantitative detector provided by the invention is as follows:

during the test, attention is paid to observing the environment of the test site, for example: conditions such as wind speed, wind direction, temperature, humidity come the preliminary judgement experimental environment and whether satisfy the requirement, whether special attention methane concentration detector 2, thermal mass flowmeter 3, direct current pipeline fan 6 can normally work. In addition, for the thermal mass flowmeter 3, whether the methane micro-leakage quantitative detector is horizontal or not needs to be judged in advance by using a level ruler 5, so that the test condition is ensured.

Later select test points such as natural gas pipeline riser, elbow or valve, at first take out air inlet hose 8, wrap up test site with seal bag 9, open direct current pipeline fan 6, make seal bag 9 be in little negative pressure state, direct current pipeline fan 6 has played the effect of trace methane and the outside air extraction and the mixture of test site leakage, when thermal mass flowmeter 3's registration tends to the stability, can begin to record corresponding methane concentration detector registration, can adopt the great methane concentration detector 2 of measurement concentration range earlier in the test process, if the concentration that shows is on the small side, can change into another methane concentration detector 2 that measurement concentration range is less.

For the air suction device, two devices, namely a pipeline direct current fan and an air pump, can be selected to be matched with two methane concentration detectors 2 with different concentration measurement ranges, so that the methane concentration range which can be measured under different flow ranges can be judged. When selecting pipeline direct current fan, the fan is from taking the battery, portable to being equipped with frequency modulation device, can adjusting the flow of fan in certain extent, thereby obtain the measuring range of different concentrations. When the air pump is selected, since continuous operation for a long time is not possible, the test duration should be noted, and the operating flow rate range of the air pump should be simply detected with a flow meter before the test.

And finally, after the effective data is read, the direct current pipeline fan 6 is closed, the sealing bag 9 is taken down, the air inlet hose 8 is collected, and the test is finished.

The above-mentioned embodiments further explain the objects, technical solutions and advantages of the present invention in detail. It should be understood that the above-mentioned embodiments are only examples of the present invention, and are not intended to limit the present invention, and that the reasonable combination of the features described in the above-mentioned embodiments can be made, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.