SO2 emission measurement for protection of humans and the environment

Sulphur dioxide is one of the most important environmental contaminants, but is also used as a preservative, for disinfection, and as a bleaching agent. Sulphur dioxide sensors are important for monitoring this dangerous gas. An ideal solution for measuring emissions of sulphur dioxide is the FLOWEVO sensor from smartGAS. It measures the SO2 concentration in a range from 0 to 2000 ppm.

Sulphur dioxide: Even low SO2 concentrations are harmful

The colourless, toxic gas sulphur dioxide occurs primarily during the combustion of fossil fuels that contain sulphur. It emits a pungent odour, irritates the mucous membranes and can cause eye irritations and respiratory problems. If inhaled, highly concentrated sulphur dioxide immediately causes severe coughing and shortness of breath. But even lower SO2 concentrations below the perceptible threshold are hazardous over extended periods and can cause long-term damage to the respiratory tract.

Sulphur dioxide is the anhydride among sulphur-containing acids. In combination with water, sulphur dioxide present in the air results in “acid rain”, which harms and acidifies plants, water and soil, and also erodes buildings and other materials. For the annual and winter average (October to March) the European Union has defined a critical SO2 concentration of 20 µg/m3 in order to protect vegetation.

Fossil fuels are the main source of sulphur dioxide emissions

The main sources of sulphur dioxide are industrial and commercial energy and heat genera-tion systems, but high quantities of the undesirable gas are also caused by shipping and mo-tor vehicle traffic. For example, the typical SO2 concentration in the flue gas of oil-fired heat-ing systems is between 180 and 220 ppm. A precise SO2 emission measurement is therefore essential. Especially in power plants and waste incineration systems, the sulphur dioxide emission of the cleaned gas is closely monitored by SO2 sensors before it is released into the environment. Additional measurement of the SO2 concentration upstream of the flue gas de-sulphurization can further optimize the combustion and flue gas cleaning processes in order to achieve more efficient utilization of fuels.

Reliable sulphur dioxide sensors for measuring emissions

Non-dispersive infrared sensors (NDIR) of the FLOWEVO series for SO2 emission measure-ment are therefore the perfect choice. They combine excellent measuring precision with a compact and user-friendly design. The sensor of the FLOWEVO SO2 series with an SO2 measuring range of 2000 ppm features long-term stability, repeatability and reliability. Dual-beam technology ensures very low drift. The compact sulphur dioxide sensor is calibrated and temperature compensated at the factory and delivered as a plug & play solution. This allows integration in OEM systems right out of the box.

Industrial applications for sulphur dioxide

In addition to combustion processes sulphur dioxide is also released in small quantities due to process-related SO2 emissions in industrial and commercial applications of the chemical in-dustry, as well as metal production and in the processing of petroleum and natural gas. In addition, sulphur dioxide is used for preserving fruits and vegetables, for the preservation of must and wine, and in the disinfection of tanks and drums. The sulphurous acids produced by sulphur dioxide and their compounds inhibit the growth of mould and various yeasts at a concentration as low as 20 mg/kg. Sulphur dioxide is also used as a bleaching agent. For process monitoring, lab analysis and for reasons of industrial safety, the measurement of the SO2 concentration with sulphur dioxide sensors is important in such processes. 

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