Online analytical instrument for synthetic liquid nitrogen washing
Thread Content
Our plant monitors the CO2 content at the outlet of the molecular sieve after treatment with liquid nitrogen (0–5 ppm), as well as the CO content in the syngas resulting from this treatment (0–10 ppm). ABB infrared analyzers are used for these measurements. Why does the reading show a negative value every time after calibration, preventing the DCS system from detecting the values? What is the problem?
There is a problem with the sample gas; it is necessary to prepare a sample gas with composition proportions roughly identical to those of the process gas. Furthermore, the manufacturers responsible for preparing the sample gas have not done a good job in controlling the concentrations, such as removing trace amounts of pure nitrogen. Try finding another good sample gas manufacturer.
Under normal conditions, it is not possible to detect the liquid nitrogen washing outlet; zero drift or calibration errors in the analyzer are quite common. Nowadays, samples are often taken from the lower layers of the liquid nitrogen cooling tank, so that it is at least possible to detect it. It’s mainly about trends.