At AISTech/METEC, Promecon will present the McON IR system for rapid in-situ measurement of the composition and amount of waste gas at electric arc furnaces. The measured values can be used to better utilize the chemical energies in the waste gas and minimize thermal waste gas losses. In addition, they reduce the energy requirements of the furnace and thus enable optimization of the entire process. Until now, the measurement of waste gas from electric arc furnaces involved intrusive sensors or extractive measurements in the waste gas duct. These could only provide the measured values with a delay, otherwise a high maintenance effort was required. In contrast, the new McON IR sensors operate on an infrared basis and do not require lances to protrude into the exhaust gas channel. They measure the chemical composition as well as the temperature and velocity of the exhaust gas flow directly at the manifold of the exhaust channel.
Infrared detector
The system's infrared detector captures a large portion of the cross-section of the exhaust gas channel. The sensor measures the active infrared emission of the individual gas molecules and uses this to determine the concentration of gases such as carbon monoxide, carbon dioxide and methane. It also detects water in the exhaust gas stream - an aspect that is playing an increasingly important role in safety at the melting furnace. A second pair of sensors measures the flow velocity and temperature of the exhaust gas.
The sensors are installed immediately after the ventilation slot on the manifold - i.e. very close to the furnace. Installation between the water-cooled piping is very simple because no components protrude into the cross-section of the pipe. The optics are purged with nitrogen, and the sensor electronics are cooled. The sensors achieve service lives of up to twelve months, helped by the protected cable routing and additional flame protection. The new sensors have a significantly higher availability compared to other intrusive systems, also due to the low maintenance requirements. Thus, the new system creates a high potential for minimizing the energy demand of electric arc furnaces.
"The new McON IR sensors work so fast that the measurement results can be used for real-time control of the furnace, for example for the oxygen lances or the gas burners," explains Hans Georg Conrads, managing director at Promecon.
