A low-power and small-volume long-term on-duty deep-sea trace gas in-situ measuring instrument

Abstract

The invention discloses a low-power consumption and small-volume long-term on-duty deep-sea trace gas in-situ measuring instrument, which includes a plug-in unit, which is detachably arranged outside the main cabin, and is used for extracting trace gas dissolved in seawater for detection in the main cabin. , and diffuse the waste gas generated after the detection of the main chamber into the degassed seawater; the main chamber is equipped with an intake pump, a drying unit, a gas detection unit and an exhaust pump inside, and the gas outlet of the external unit passes through the intake pump, the drying unit Afterwards, it is connected with the gas inlet of the gas detection unit, and the gas outlet of the gas detection unit is connected with the gas inlet of the external unit through the exhaust pump. In the plug-in unit of the present invention, the separation of water and gas and the diffusion and removal of waste gas can be carried out synchronously without interference, and the main compartment and the plug-in unit work independently of each other, reducing the possibility of human misoperation and multiple switching compartments affecting the airtightness and causing water ingress. And there is no need to open the warehouse for ventilation maintenance, realizing long-term detection.

Description

technical field [0001] The invention relates to the technical field of deep-sea gas detection, in particular to a low-power, small-volume, long-term on-duty deep-sea trace gas in-situ measuring instrument. Background technique [0002] In today's energy shortage situation, the development of gas hydrate and oil and gas resource detection technology has risen to the height of national strategy. It is roughly estimated that the prospective resources of hydrates in my country's sea and land areas are about 80 billion tons of oil equivalent, which is twice the amount of conventional natural gas resources in my country. The concentration of dissolved methane in the bottom water of normal sedimentation is low, and its value is 0.5-2nmolL -1 However, in sea areas with gas hydrates, oil and gas reservoirs, ocean ridge hydrothermal systems, and anaerobic sediments rich in organic matter, a large amount of methane is produced in the lower part of the sediments, which enters the botto...

AI Technical Summary

Problems solved by technology

[0005] The methane detection instrument based on CRDS technology, taking the American LRG deep-sea methane ring-down spectrometer as an example, the components are integrated in a sealed and pressure-resistant cylindrical shell, and the water-proof and breathable membrane for gas-liquid separation is set on the end face of the shell , in practical application, it has the following deficiencies: 1. The permeable membrane is a sheet structure, the effective contact area with seawater is small, the gas extraction efficiency is low, the single measurement time is 4 to 5 minutes, and it is easily affected by seawater. Pollution, the working cycle is only 4 to 7 hours, frequent membrane changes are required, and frequent opening and maintenance will affect the airtightness and cause the possibility of water ingress, reducing the safety of the instrument

2. The water-proof and breathable membrane is used as the internal and external connection channel. In order to ensure the penetration efficiency, the thickness of the permeable membrane is generally on the order of microns, and it is easy to be damaged under the action of external force. Once the water-proof and breathable membrane is damaged, the seawater will directly enter the inside of the instrument. damage the instrument

3. The exhaust gas generated during the detection process (including the detected gas or the newly generated gas) adopts the gas storage and recovery method, that is, the exhaust gas is stored, and exhausted in the air after the instrument is recovered. The capacity of the exhaust gas pool greatly limits the deep sea In-situ gas continuous detection time

However, if the direct exhaust method is adopted, in order to overcome the hydrostatic pressure in the deep sea, the pre-stage booster device needs to pressurize the exhaust gas to a corresponding pressure. The exhaust gas exhausted by the booster pump will accelerate the loss of power. As the depth of sea water increases, the greater the pressure of the booster pump will lead to greater loss, and the consumption of the battery will shorten the use time of the instrument.

Therefore, conventional methods of pressurized exhaust or recovery to the water surface are unable to meet the long-term continuous observation of trace gases in the deep sea.

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