Device and method for simultaneously measuring components and flow of methane

Abstract

The invention relates to a device and a method for simultaneously measuring components and flow of methane. The method comprises the following steps: controlling an output signal of an amplifying circuit through an automatic gain circuit, identifying that whether a gas to be measured is air or methane through judging the relative size of an ultrasonic signal, if the gas to be measured is the methane, measuring the sound velocity of the methane through an ultrasonic sensor, measuring the temperature of the methane through a temperature measuring unit, calculating the volume concentration of CO2 gas in the methane by using a mixed gas characteristic equation, calculating the volume concentration of vapor by using a relation between the temperature and saturated vapor pressure, finally obtaining a volume concentration of CH4 gas, and measuring the flow of the methane through measuring a time difference between fair current and adverse current of the ultrasonic signal. According to the method, through treating signals measured by one temperature sensor and one ultrasonic sensor, the components and the flow of the methane can be measured, and an effective solution is provided for low-cost requirement in methane industrial application.

Description

technical field [0001] The invention relates to a device and a measuring method for gas composition and flow, in particular to a device and a measuring method for simultaneously measuring biogas composition and flow. Background technique [0002] In industrial production, gas concentration detection technology is widely used in chemical processing, environmental protection detection and power industry and other fields. At present, there are many methods for detecting gas concentration, such as chemical analysis method, infrared absorption method, corona discharge method, ultrasonic detection method, etc. . The chemical analysis method is not suitable for on-line detection; the corona discharge sensor has a short life and cannot work stably for a long time; the infrared absorption method is complex and bulky, and the cost is high, so it is difficult to popularize. The use of ultrasonic waves to measure the concentration of ternary gases has the characteristics of wide measur...

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Problems solved by technology

[0012] 2. The measuring gas should be as pure as possible, especially CO 2 The content should not be too high, usually less than 10%, because CO 2 The attenuation of ultrasonic waves is very large, CO 2 When the concentration is high, it is very unfavorable for the reception of the signal

[0022] To sum up, no one or company has conducted research on the simultaneous measurement of biogas composition and flow rate using ultrasonic principles. A simple analyzer that uses infrared technology to detect the concentration of methane in biogas generally costs tens of thousands of yuan. The price of an ordinary precession vortex flowmeter for measuring gas flow is generally around 5,000 yuan

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