LowNOx

LowNOx refers to a set of technologies and practices aimed at reducing the emission of nitrogen oxides (NOx) from combustion processes. NOx, consisting mainly of NO and NO2, forms at high flame temperatures when nitrogen in air and fuel reacts. Lowering NOx helps reduce air pollution, smog, and acid rain, and supports compliance with environmental regulations across power generation, industry, and transportation sectors.

Key approaches include:

- Low-NOx burners and staged combustion, which reduce peak flame temperatures through air or fuel staging.

- Flue gas recirculation (FGR), which lowers flame temperature by diluting the combustion zone with inert exhaust gases.

- Combustion optimization and lean premixed or staged fuel-air mixtures to minimize nitrogen conversion.

- Post-combustion controls such as selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) to convert NOx to nitrogen and water.

- Use of cleaner fuels (for example, natural gas) and, where feasible, fuel switching or optimized boiler load management.

- Water or steam injection in some systems to lower peak temperatures and NOx formation.

Applications span power plants, industrial boilers, gas turbines, marine engines, cement kilns, and waste-to-energy facilities. Benefits include lower NOx emissions and improved regulatory compliance, while trade-offs can include higher capital and operating costs, potential impacts on CO or unburned hydrocarbons, and the need for catalyst maintenance and system integration. Measurement and monitoring of NOx are essential for performance verification and compliance.