Hierarchical methods to improve the performance of the SiC-FET as SO_2 sensors in flue gas desulphurization systems

摘要

Experiments were performed both in the laboratory and a desulfurization pilot unit in order to improve the SiC-FET sensor performance using two-step data evaluation. In both cases, a porous Pt-gate enhancement type SiC-FET was utilized in a temperature cycled operation (TCO). Liner Discriminant Analysis (LDA) was chosen as the method for multivariate data analysis. Hierarchical methods with two-step LDA worked quite well in the laboratory tests with SO_2 concentrations varied from 25 to 200 ppm. The same data evaluation was also applied to tests in the desulfurization pilot unit, with higher gas flow and a larger SO_2 concentration range (up to 5000 ppm). The results from the SO_2 quantification showed a significantly improved fit to corresponding reference instrument (FTIR) values.