Laser-based infrared spectroscopy for measuring sulfur trioxide in gas power plant exhaust gas

摘要

The present invention relates to a method for determining the sulfur trioxide content in gas (1). A sample (2) of gas (1) is taken and the gas pressure of sample (2) decreases. A wavenumber resolved transmission measurement is performed on sample (2) using a wavenumber variable monochromatic light source (3) and the sulfur trioxide content is derived from the measurement. The measurement is carried out in the sulfur trioxide absorption band between 1360 and 1410 cm −1, in particular in the window around the sulfur trioxide absorption at 1365.49 cm −1. The invention further relates to a method for operating a power plant (7), to a measurement system (10) for determining the sulfur trioxide content in the gas (1) and to the power plant (7).