A device and method for measuring dissolved methane in water

Abstract

The invention discloses a device and method for determining dissolved methane in water, and relates to detection of dissolved methane in water. The device is provided with a nitrogen steel cylinder, a first reducing valve, a mass flow controller, a second reducing valve, a flowmeter, a six-way valve, a first three-way valve, a second three-way valve, a Nafion tube, a semiconductor refrigerator, a scavenging duct, a trapping tube, a liquid nitrogen storage tank, an electric heating tube, a twelve-way valve, a Koren pump, a sample bottle and a gas chromatograph. The method comprises the stages of 1, sampling, 2, purging, 3, trapping, 4, analyzing, and 5 separation and detection. The device and method have the advantages that consumed time is short, the flexibility is high, the automatic degree is high, and operation is easy; the liquid nitrogen storage tank is adopted for containing liquid nitrogen to be used as a low temperature source of the trapping tube, methane gas can be completely trapped onto a molecular sieve under the temperature of subzero 100 DEG C. The electric heating tube is heated to 100 DEG C or more within 0.5 min, the methane can be rapidly analyzed and enters a gas chromatograph, and the Koren pump can achieve accurate measurement of the concentration of methane.

Description

technical field [0001] The invention relates to the detection of dissolved methane in water bodies, in particular to a device and method for measuring dissolved methane in water bodies. Background technique [0002] Methane is the most important organic trace gas in the atmosphere, its greenhouse effect is 20 times that of the same amount of carbon dioxide, and plays an important role in atmospheric chemistry. The concentration of methane in the atmosphere is increasing by 1% per year, showing an imbalance in its sources and sinks. The ocean is the net source of methane in the atmosphere. The distribution characteristics of methane in many oceans and coastal waters of the world have attracted the attention of many scientists. At present, the most commonly used method is gas chromatography. First, the water sample is pretreated to obtain dissolved gas, and then the gas is injected into the chromatographic column. After separation, the gas is detected by a flame ionization de...

AI Technical Summary

Problems solved by technology

Although early researchers used dry ice cold traps, or semiconductor refrigeration and other technologies to adsorb methane gas on molecular sieves, but because the temperature is not low enough, part of the adsorbed methane will slowly lose, resulting in inaccurate detection results

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