An in-situ detection system for methane concentration in seawater

Abstract

The invention relates to a system for detecting the methane concentration of seawater in situ. In the system, bottom seawater in a measuring line enters a reducing valve through a filter, so that the pressure of the seawater is lowered to normal pressure; normal-pressure sample water flows into a gas-liquid separating device after being adjusted by a flow valve; a seawater sample is separated into sample water and sample gas by the gas-liquid separating device; the sample water is collected by a sample water collector; excessive sample water flows into a waste water compressive cabin; the sample gas is collected by an automatic sample valve, and is conveyed into a gaseous hydrocarbon detection device for testing; the excessive sample gas is emptied, and is adsorbed by chemical adsorption equipment; the sample gas enters the gaseous hydrocarbon detection device; target gas undergoes a reduction oxidation reaction through a high-sensitivity gas element to generate an electric signal; and the electric signal is acquired by corresponding chromatogram software, is converted into a digital signal by using analog-digital conversion equipment, and is transmitted to a PC (Personal Computer) on a boat through an optical cable to realize data display. The system has the advantages of capability of detecting the methane concentration of a seabed in situ, high accuracy, small interference and accurate data.

Description

technical field [0001] The invention relates to an in-situ detection system for methane concentration in seawater, which belongs to the field of geochemical detection of marine natural gas hydrate and oil and natural gas resources. Background technique [0002] Gas hydrate is known as an alternative energy source in the future world. A large number of regional geological surveys for marine gas hydrates have been carried out around the world. The main survey techniques used include geophysical prospecting, geochemical prospecting, and drilling sampling. In addition, technologies such as seabed in-situ imaging, magnetotellurics, satellite remote sensing, and optical detection are also in the research and development and testing stages; gas hydrate exploration technologies are developing in a diversified direction. [0003] The geochemical exploration method of marine natural gas hydrate is an exploration method and technology applied in the mid-1980s, mainly through qualitativ...

AI Technical Summary

Problems solved by technology

The biggest problem with this instrument is that it cannot quantitatively obtain the volume of gas entering the device through the filter membrane, so it can only qualitatively obtain the concentration change of methane in seawater

Although the specific indicators of the instrument are: its detection sensitivity measurement range: between 50nmol / L-10000nmol / L, it cannot meet the background of methane in the seawater of the South my country Sea: 0.1-10nmol / L, and the high-precision observation is mostly distributed around 4nmol / L needs

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