During combustion of gas, oil or solids (coal wood, etc.), gaseous combustion products are generated which are called flue gas, exhaust gas or emission. Depending on the type of fuel and the combustion equipments, the distribution of the gaseous substances in the flue gas is quite different.
From an energetic point of view, optimal combustion takes place at a stoichiometric ratio of 1 between the fuel and the required oxygen. However, in practice the value is always slightly larger than 1. The distribution of the unwanted pollutants is strongly dependent on this so-called lambda value and is shown as an example in the following figure.
The monitoring of the exhaust gases in combustion processes is therefore derived from the above-mentioned efficiency reasons and furthermore from the legally prescribed limit values. Combustion processes which are subject to monitoring for example:
- power plants
- incineration plants
- natural gas furnaces
- gas turbines
- blast furnace gas
- oil firing (also on ships)
In particular, the concentration values of nitric oxide, sulfur dioxide, carbon monoxide must be detected down to the lower ppm range. These measurements are carried out continuously, so that an operating time of more than 8000 hours per year can be expected. ULTRA.sens® and INFRA.sens® are suitable for this trace analysis.