Study On Method And Equipment Of Measuring Moisture Content In Gas With High Precision

A system for high-performance moisture content measurement based on gravimetric method is researched and developed in this work. This device that uses high-purity ultrafine fiber glass has the advantages of little measurement error, well repeatability, easy operating, fast measurement and so on, and its measurement error is less than 0.2 mg/m3. The work in this paper is divideed into three parts:Firstly, the principle for moisture content measurement based on gravimetric method is introduced.Then, the most important part, a system for high-performance moisture content measurement based on gravimetric method is invented. The measurement accuracy has been improved obviously by designing the structure of the sampling pipe over again. High-purity superfine fiberglass with diameter 2~5μm span and RH88 microfibre tube made in Whatman Ltd. in England is carefully choosed and all filter material meets the needs of this measurement system. When the moisture in gas pass through the filter material, it will be headed off more than 99%. Then, according to the gas volume pass through the sampling pipe in unit time, the moisture content in gas can been calculated at once.In the last part of this work, in order to further verify the feasibility of that system, we have choosen ShaGang group Ltd. as the experiment place to carry out the experiment. The standard deviation of the result is 0.2 mg/m3, and when the diameter of fiberglass is between 2~5μm, the collected efficiency is more than 99%. In order to examinate the repeatability of the system, three measuring methods on the moisture content in gas is choosen. The results show that the only method that can measure the moisture content are fiberglass filtering method, and its standard deviation is 9.2 mg/m3. It's confirmed that the system for high-performance moisture content measurement based on gravimetric method is able to achieve a very good measurement result.Based on the method developed by us, the measurement accuracy of the instrument for moisture content measurement based on gravimetric method is greatly increased and it will be widely used.