High-resolution spectroscopy of gases at elevated temperatures for industrial applications

In situ simultaneous fast measurements of gas temperature and gas composition are of great interest in combustion/gasification research and power plant engineering and give useful information about conditions, chemical reactions and gas mixing in various industrial processes. Usually gas measurements have to be done in a very aggressive and unstable in time hot gas environment which is realized, for example, in boilers, gasifires and engines. An optically based technique is beneficial because it is non-intrusive, accurate, fast and can be performed in situ for various extremely hard conditions. The quality of the in situ gas composition measurements depends, among other things, on the quality of reference data (i.e. partial absorption spectra gases of interest) which are in general highly temperature dependent. Existing databases (e.g. HITRAN, HITEMP or CDSD) can normally be used for absorption spectra calculations at limited temperature/pressure ranges. Therefore experimental measurements of absorption/transmission spectra gases of interest in combustion (e.g. CO2, H2O or SO2) at high-resolution and elevated temperatures are essential both for analysis of complex experimental data and further development of existing and developing new databases. Measurements should be performed at well-controlled conditions in a highly temperature uniform heated gas cell with a high-resolution spectrometer.

In this work some high-temperature, high-resolution IR absorption/transmission measurements gases relevant to combustion (e.g. CO2, H2O, SO2, SO3 and NH3) are presented and discussed. The measurements have been performed in several high-temperature gas cells available at DTU Chemical Engineering with use of two high-resolution FTIR spectrometers. Two examples of successful industrial and academic partnerships in frames of national and international ongoing projects are shown, namely with DONG Energy (Denmark) and University College London (UK).