Steel industry plants all over the world have multiple processes, most of them emitting CO and CO2 in very high concentrations (tens of %). CO is used as a combustible due to its high calorific value. It is stored in a huge tank before it is used by the power plant next door. CO in such high concentration is explosive in presence of a few molecules of oxygen. Therefore, continuous monitoring of the O2 concentration in the duct carrying the gas to the tank is a key and a safety issue.
So far the measurement task was achieved using an extractive setup.
But because of the dirty conditions (mud and mist) the sample conditioning system was expensive and very demanding in maintenance. Filters needed to be changed or cleaned very often. Gaskets, pumps and other parts were consumables.
See picture 1. The service department was harassed by the maintenance tasks around this critical measurement.
The gas to be measured is a very dirty and humid gas. Very often one can even find mud and water flooding in the duct. The gas contains mainly CO (%), CO2 (%) and water, sometimes a bit of H2, therefore it must not contain O2, otherwise it could lead to an huge explosion.
The specificity of the process gas creates headaches when using the extractive method due to high maintenance effort.
Therefore, the laser technique is an ideal solution because it is in situ. The sensors are mounted directly at the process, without the need of sampling.
Additionally, it provides a fast and reliable (no drift) measurement.
See Picture 2 how simple the installation is in comparison with Picture 1 which is even just showing the sampling system, the analyzer is in an additional separate cabinet!
The SITRANS SL in-situ Laser Gas Analyzer offers best possible capabilities for this application. It gives a real time safety measurement of the O2 level in the flue gas.
The laser in-situ measuring principle is best suited for this task because it provides the plant operator with measuring data in real-time for fast reaction. The accuracy of the device is granted by the countinuous measurement through the internal oxygen filled reference cell. This proves the correct operation even in the (standard) situation of 0 % process oxygen. This feature leads to zero drift of the measured value over the time. No preventive maintenance is required.
On top of the fact that the device does not drift over the time is a very special guarantee for the end user.
The list of user benefits includes:
- Reduced risk of explosion
- Reduced maintenance
- Higher availability rate
- Safer technique with an internal reference cell signal always available