Plant & Works Engineering July/August 2022

24 | Plant & Works Engineering www.pwemag.co.uk July/August 2022 Energy & Environmental Management Focus on: Boilers, Burners & Controls N itrogen and oxygen are the two main components of atmospheric air, but they do not react at ambient temperature. However, in the heat of combustion, such as in a vehicle engine or within an industrial furnace or process, the gases react to form nitrogen oxide (NO) and nitrogen dioxide (NO2). This is an important consideration for the manufacturers of combustion equipment because emissions of these gases (collectively known as NOx) are tightly regulated. Nitrogen dioxide gas is a major pollutant in ambient air, responsible for large numbers of premature deaths, particularly in urban areas where vehicular emissions accumulate. NO2 also contributes to global warming and in some circumstances can cause acid rain. A wide range of regulations therefore exist to limit NOx emissions from combustion sources ranging from domestic wood burners to cars, and from industrial furnaces and generators to power stations. The developers of engines and furnaces therefore focus attention on the NOx emissions of their designs, and the operators of this equipment are generally required to undertake emissions monitoring to demonstrate regulatory compliance. The role of monitoring in NOx reduction NOx emissions can be reduced by: n Reducing peak combustion temperature n Reducing residence time at the peak temperature n Chemical reduction of NOx during the combustion process n Reducing nitrogen in the combustion process These primary NOx reduction methods Due to the environmental and health effects of the nitrogen oxide gases, global regulations are driving down emission limits. This creates and greater demand for monitoring and control procedures. PWE spoke to James Clements, Managing Director of UK gas analyser manufacturer Signal Group, about the current issues and unveils the latest advances in monitoring technology. Monitoring NOx emissions from combustion processes