Analysis of the causes of flow path blockage in zirconia analyzers

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During normal operation of a zirconia analyzer, the sample introduction and return pipelines are not prone to clogging; those that are likely to get clogged are the nitrogen gas circuit in the analyzer’s gas path module and the flame arresters before and after the detector. When instrument air is supplied to the calibration gas port, the zirconia detector exhibits a slow change in potential; this is usually due to aging of the zirconia detector, and it is necessary to replace it with a new one before conducting further tests. During the use of the analyzer, record the flow and temperature monitoring values when it is operating normally, and compare them with the current flow and temperature values; if the changes are small, it indicates that the gas path is unobstructed ； If the temperature value drops significantly, it indicates that there is a blockage in the gas path. Compare the detector potential when the analyzer is in use with that when nitrogen is vented to the atmosphere at the exhaust port; if the detector potentials are similar in these two conditions, it indicates that the sampling and return flow paths of the analyzer are functioning properly ； If the deviation is large, it indicates that the injection and return flow paths are blocked. When it is determined that there is a blockage in the gas path of the analyzer, stop the flow of nitrogen; then introduce instrument air at a pressure 0.07 MPa higher than that in the process pipeline, with a flow rate of 80 L/h, into the standard gas port. If the temperature indicated by the flow and temperature sensor drops rapidly, it indicates that the sampling flow path is unobstructed; if the temperature drops slowly, then there is a blockage in the sampling flow path. After turning off the nitrogen purge and introducing instrument air to the calibration gas port, if the potential of the analyzer’s detector changes rapidly, it indicates that the detector is functioning properly and the sample return circuit of the analyzer is in good order ； If a blockage occurs, it is usually in the nitrogen gas circuit and the flame arrester within the gas circuit module. At this point, it is necessary to cut off the instrument air and open the ball valve at the calibrating port of the analyzer; since no process gas is discharged, it can be inferred that either the internal calibration tube of the analyzer or its internal flame arrester is blocked. The above are the reasons for blockages in the flow path of zirconia analyzers. It is necessary to make accurate judgments based on the actual situation and resolve these blockages promptly to ensure normal production operations.