Calculation method for detection limit in gas-leakage infrared imaging

Abstract

The invention relates to a calculation method for detection limit in gas-leakage infrared imaging, and belongs to the field of gas leakage detection. The calculation method comprises the following steps of: firstly calculating the background radiant exitance when no gas leaks, and taking the background radiant exitance as background radiant exitance for imaging detection; calculating equivalent blackbody temperature of the imaging detection background by the background radiant exitance for imaging detection; secondly, when gas leaks, calculating the radiant exitance after the background radiation is absorbed by gas according to a gas parameter in the background radiant exitance for imaging detection, namely a target radiant exitance for imaging detection; calculating target equivalent blackbody temperature for imaging detection by the target radiant exitance for imaging detection; then calculating an absolute value of the difference between the imaging detection background and the target equivalent blackbody temperature, and defining the absolute value as a gas equivalent blackbody temperature difference; and finally comparing gas equivalent temperature difference with a noise equivalent temperature difference of comprehensive performance parameters of an infrared detector and an optical system, and determining gas-leakage detection limit value, namely, a minimum flow of leaked gas.

Description

technical field [0001] The invention relates to a calculation method for gas leakage infrared imaging detection limit, which belongs to the field of gas leakage detection. Background technique [0002] According to the statistics of my country's tank container / tank truck transportation industry, so far, my country has transported more than 130 kinds of hazardous chemicals, among which the transportation of toxic, harmful, flammable and explosive gases is the top priority. For example, in addition to liquefied petroleum gas, my country's annual output of chlorine alone has exceeded 6 million tons, and 0.1 mg of chlorine per cubic meter of air is enough to cause harm to the environment and personnel. According to the national "Chlorine Gas Safety Regulations GB 11984-89", the workshop (workplace) that produces and uses chlorine gas, the maximum allowable concentration of chlorine gas in the air is 1mg / m 3 . During the transportation of hazardous chemicals, the leakage of tox...

AI Technical Summary

Problems solved by technology

[0005] Although gas leakage infrared imaging technology has many advantages such as portability, rapidity, and large-scale telemetry, the current passive gas leakage infrared imaging technology is a fast qualitative detection technology based on human eye observation, which cannot achieve quantitative trace gas concentration detection.

When the gas leakage flow rate is very small, the gas cloud concentration is very low, so that I 0 and I 1 If the difference is small, the gas cloud cannot be imaged. Since the passive gas leakage infrared imaging technology cannot realize the quantitative detection of gas concentration, it will bring inconvenience to the design of the gas imaging system and the performance evaluation of the system.

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