Methane detecting fiber grating process and equipment

Abstract

The present invention discloses methane detecting fiber grating process and equipment. Platinum film is coated on the fibers on two sides of the grating to catalyze the oxidation reaction between oxygen in the air and methane, the reaction released heat causes the fibers to deform and the grating reflection peak to drift, and the wavelength of the reflection peak is determined so as to measure the concentration of methane in gas. When one set of methane sensors, one wideband light source and one wavelength division multiplexing demodulation system are connected with cycling devices, the distributive measurement with methane sensors may be realized.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing, in particular to a method and equipment for optical fiber grating methane detection. Background technique [0002] Methane (CH 4 ) is the main component of mine gas, natural gas, biogas and various liquid fuels. It is an important industrial raw material and daily life gas. It is also a flammable and explosive gas. The lower limit of explosion in the atmosphere is 5.3%, and the upper limit is 15.0% . At the same time, it is also considered to be one of the most important gases for the greenhouse effect. It is reported that CH 4 The ability to absorb infrared rays is CO 2 15 to 30 times of that, accounting for 15% of the contribution of the entire greenhouse. CH in air 4 The concentration is increasing at a rate of about 1% per year. Therefore, timely detection of CH 4 The generation source, leakage source and concentration of gas play a very important role in the safe operati...

AI Technical Summary

Problems solved by technology

However, some problems were found during use. For example, because the surface of the grating is directly coated with a catalyst, the catalyst promotes the oxidation reaction of methane and oxygen to generate heat that directly deforms the grating. The grating will be easily deformed due to excessive temperature rise. Although the service life can be extended by replacing the grating, the process of making the grating and coating the catalyst on it is relatively complicated and the cost is relatively high, and because the catalyst is directly coated on the surface of the grating, the grating cannot be packaged and must be sealed. It is exposed outside, has low mechanical strength, is greatly affected by the external environment, etc., and the coating range of platinum film is limited by the width of the grating

Images