Measuring method and device for trace and ultra-trace oil content

A measuring device for trace and ultra-trace oil content, comprising:

• a cryogenic enriching device to enrich and sample trace and ultra-trace oil components in a gas;
• an extracting device to extract the oil components, connected to the cryogenic enriching device;
• and
• an infrared spectrometer to analyze oil content from extraction liquid, connected to the extracting device;
• wherein the cryogenic enriching device includes a Dewar container to receive and discharge liquid nitrogen, and a U-shaped pipe soaked in the liquid nitrogen, wherein the gas circulates in the U-shaped pipe to form a liquid nitrogen cold trap to realize enriching and sampling of oil components in the gas;
• wherein the extracting device includes a container to store an extractant, an input pipe to input the extractant into the U-shaped pipe, an outlet pipe to export the extraction liquid, and an extraction liquid quantitative pipe, wherein the extractant in the input pipe flows into the U-shaped pipe from near the gas inlet thereof, the extraction liquid obtained by extracting flows out of the U-shaped pipe from near the gas outlet thereof and is stored in the extraction liquid quantitative pipe after flowing through the outlet pipe, and the extraction liquid quantitative pipe is employed to measure the volume of the extraction liquid;
• wherein the U-shaped pipe is further provided with a mass flowmeter to measure the total mass of the passed gas, and the oil content in the gas is calculated according to the measured total mass of the gas and the oil concentration of the extraction liquid measured by the infrared spectrometer.