How is on-site analysis of oxygen and nitrogen done?

This post was last edited and replied to by chengjingbao on 2010-8-11 21:12. Reply 1# Wu Zhijun: Generally, the principles behind pure oxygen analysis performed in situ are mainly thermal conductivity type, magnetic machine type, and magnetic pressure type. For nitrogen, there are electrolysis, fuel cells, zirconia, and similar methods.

For such high-purity oxygen, online chromatography is the best option for on-site analysis; it does not directly measure the purity of oxygen but rather detects the impurities present in it, with the concentration of oxygen being determined through subtraction. The analysis of pure gases generally involves using chromatography to detect impurities in them. Especially high-purity gases. Pure gases are hard to find, as are more pure standard samples; so it’s better to analyze the impurities instead.

Our unit’s air separation plant requires such measurements; we use online analytical instruments, specifically high-purity oxygen online analyzers, and we also conduct manual comparisons. There is an analysis booth on site, where the sample gas is introduced into the sampling cabinet there, and measurements are taken manually using a Hampton meter for comparison

Reply to 4# lovegxc: What exactly is that Hamp instrument you mentioned?

Hampy (solid absorber), also known as a pure oxygen analyzer: this instrument is made of borosilicate glass welded together using lamp welding techniques, with capillaries used in its construction. It is finely crafted and of high quality; it needs to be mounted on a wooden frame when in use. It is suitable for solid absorbents and for holding fillers used to absorb gases; it is used in oxygen plants for conducting purity tests on oxygen and nitrogen. Design and principle: This instrument consists of a circular absorption sphere welded to another circular sphere. There is an opening at the bottom of the absorption sphere, which allows the insertion of solid absorbents or fillers, after which it is sealed with a rubber stopper. A capillary tube is attached to the upper end of this sphere, and it is used to connect to the gas measuring device. Its principle is similar to that of the Ohr method of gas analysis; a copper-ammonia solution is used as the absorbing liquid, along with fine copper wires with a purity of over 99.5%. This analyzer can determine the purity of oxygen within the range of 90% to 100%, with an accuracy of 0.1%. You can find diagrams of this device by searching on Baidu

This post was last edited by chengjingbao on 2010-8-12 07:22. In industrial production, online chromatography has not yet been found to be used for measuring oxygen purity. In China, oxygen purity was measured using Olschler instruments since the 1950s; from the late 1950s to the 1970s, domestically produced thermomagnetic online analyzers were commonly used, in conjunction with offline analysis methods. In the 1970s, magnetometers were used in combination with offline analysis. After that, a large number of imported online instruments flooded into China; most of them use online analysis. The measurement methods were mentioned on the second floor, and the \"Online Analysis Instruments Manual\" explains them even more clearly! The subtraction method used in chromatography is an analytical technique for mass analysis and is not very suitable for on-site control analysis.

The Hampy instrument mentioned on the fourth floor is for use when the carbon monoxide level is extremely low, right?

This post was last edited and replied to by zbx on 2010-8-17 06:30. Reply 8# fxswl: Yes, because Hamp instruments are capable of absorbing CO. The original poster mentioned the purity of oxygen; there is also nitrogen present, so CO should not be present. Based on what he said, it’s the oxygen obtained after air separation that should be tested, as it contains virtually no CO. Therefore, those of us who work in analysis and testing also need to be familiar with the manufacturing process, otherwise we won’t know how to use the appropriate methods

Oxygen can be analyzed on-site and in real time using an oxygen analyzer~~~~ For nitrogen, analysis is done using trace oxygen~~

An online gas analysis system is used