Development of a TG-FTIR system for investigations with condensable and corrosive gases

Abstract

A thermogravimetric analyzer and a Fouriertransform infrared (FTIR) spectrometer were combined and redesigned for investigations with corrosive and condensable reactive gases. The standard gas inlet and outlet of the thermogravimetric analyzer were changed in order to heat the gas tubes, which are lead through the flanges, and avoid condensation in these parts of the system. Furthermore, all tubes upstream and downstream of the thermogravimetric analyzer were trace heated up to 180°C. The gas measuring cell of the FTIR spectrometer was designed such that an optimum compromise between the small flow rates through the thermogravimetric analyzer and a short residence time of the gases in the gas measuring cell could be achieved. The gas supply allows the dosage of different gas compositions containing nitrogen, oxygen, water, NH 3 , and NO 2 , for example. The system was validated by analyzing the composition of a diesel particulate matter (PM) sample with a temperature-programmed desorption followed by oxidation (TPD/O) experiment, which showed good agreement with the established analysis methods. The reactivity of the PM sample was investigated by temperature-programmed oxidation (TPO) experiments with different reactive gas mixtures of oxygen, water, and NO 2 in nitrogen. By adding NO 2 , the soot oxidation started at lower temperatures and the addition of water lead to a shift of the maxima of the carbon oxidation rates to lower temperatures. The ratio of formed CO 2 and CO was shifted to higher values by the addition of NO 2 and water whereby the influence of water was much more pronounced.

Quantification of Gaseous Urea by FT-IR Spectroscopy and Its Application in Catalytic Urea Thermolysis

“…With additional efforts for temperature optimization and downscaling of void volumes, significantly higher urea concentration may become accessible while keeping urea decomposition insignificant. The volume of the FT-IR gas cell may be largely decreased by using the cell design presented in [21].…”

Selective Catalytic Reduction of NOx with Ammonia over Soot

“…25 This system allowed the quantification of the elemental and organic carbon (EC and OC) contents plus the amounts of oxygen, hydrogen, organic nitrogen, organic sulfur and sulfuric acid (detected as SO 2 ), and water as well as the ash content. 25,26 In addition, the Brunauer−Emmett−Teller (BET) surface areas of the samples were measured using nitrogen physisorption on a Quantachrom Autosorb 1-c instrument, and the ash was characterized using ICP-OES measurements on a Varian VISTA PRO AX instrument.…”

“…The composition of the four soot samples was analyzed on a TG-FTIR system (thermogravimetric analyzer TGA/DSC1 from Mettler-Toledo combined with an Antaris IGS Fourier-transform infrared spectrometer from ThermoScientific) that was specially equipped for the characterization of soot samples . This system allowed the quantification of the elemental and organic carbon (EC and OC) contents plus the amounts of oxygen, hydrogen, organic nitrogen, organic sulfur and sulfuric acid (detected as SO 2 ), and water as well as the ash content. , In addition, the Brunauer–Emmett–Teller (BET) surface areas of the samples were measured using nitrogen physisorption on a Quantachrom Autosorb 1-c instrument, and the ash was characterized using ICP-OES measurements on a Varian VISTA PRO AX instrument.…”