Online Multielement Analysis of the Top Gas of a Blast Furnace by Laser-induced Breakdown Spectroscopy (LIBS)

摘要

The continuous and simultaneous monitoring of relative concentrations of Na, K, Zn and Pb as well as C, N, O, H, Ca and Fe - being constituents of top gas and dust particles carried therein - is demonstrated by a direct laser measuring in the top gas tube of a blast furnace. The measuring method is laser-induced breakdown spectroscopy (LIBS) which uses optical emission spectrometry (OES) of a plasma generated by focussing a laser beam into the top gas stream. The LIBS instrumentation consists of laser, optics, spectrometer and electronics installed in a container near the top gas tube access. An optical probe is installed to enable a traversing of the top gas tube. Due to the CO content of the top gas, safety measures such as monitoring the absence of O2 inside and CO outside of the top gas tube have been taken. The laser-based instrumentation was set up and installed for measuring campaigns at three blast furnace sites in Germany, Finland and Spain. On-site measuring periods of up to 10 hours a day with an average measuring value every 10 s were carried out demonstrating the capability of this technique for online measuring tasks in rough industrial environments. The functionality of the system was shown succesfully and first correlations of online monitored analyses in the top gas with blast furnace parameters were found.