NOxkontroll

NOxkontroll refers to the set of measures and technologies used to limit emissions of nitrogen oxides (NOx) from combustion sources. NOx, which includes nitric oxide (NO) and nitrogen dioxide (NO2), are formed when fuels burn at high temperatures and contribute to smog, acid rain and respiratory health problems. The concept covers both transport and stationary sources such as vehicles, power plants, boilers and marine engines.

Common sources of NOx include road transport (especially diesel engines), electricity and heat production, industrial boilers and ships. NOxkontroll combines primary measures that reduce NOx formation during combustion with secondary aftertreatment methods that remove NOx from exhaust gases.

Primary measures focus on controlling the combustion process. These include optimizing combustion conditions to lower peak flame temperatures, air staging and low-NOx burners, and sometimes exhaust gas recirculation (EGR), which lowers in-cylinder temperatures and NOx formation.

Secondary aftertreatment methods treat exhaust after it leaves the engine or boiler. Selective catalytic reduction (SCR) injects a reductant such as ammonia or urea into the exhaust, passing it over a catalyst to convert NOx into nitrogen and water. Selective non-catalytic reduction (SNCR) uses similar chemistry without a catalyst. NOx adsorbers or lean NOx traps (LNT) trap NOx at lean conditions and release it for chemical reduction. Each method has considerations such as catalyst aging, ammonia slip and the need for maintenance or reagent supply.

Regulatory frameworks (for example, EU emission standards and US EPA rules) drive NOxkontroll adoption, often requiring continuous emission monitoring and reporting. While effective, NOxkontroll involves trade-offs in cost, energy efficiency and system complexity, with ongoing research into more integrated, multi-pollutant solutions.