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Selective non-catalytic reduction (SNCR) is a method to lessen nitrogen oxide emissions in conventional power plants that burn biomass, waste and coal.The process involves injecting either ammonia or urea into the firebox of the boiler at a location where the flue gas is between 1,400 and 2,000 °F (760 and 1,090 °C) to react with the nitrogen oxides formed in the combustion process.
Selective catalytic reduction (SCR) means converting nitrogen oxides, also referred to as NO x with the aid of a catalyst into diatomic nitrogen (N 2), and water (H 2 O). A reductant, typically anhydrous ammonia (NH 3), aqueous ammonia (NH 4 OH), or a urea (CO(NH 2) 2) solution, is added to a stream of flue or exhaust gas and is reacted onto a ...
A NO x adsorber is designed to reduce oxides of nitrogen emitted in the exhaust gas of a lean burn internal combustion engine.Lean burn engines, particularly diesels, present a special challenge to emission control system designers because of the relatively high levels of O 2 (atmospheric oxygen) in the exhaust gas.
Nitrogen oxides are released during manufacturing of nitrogen fertilizers. Though nitrous oxide is emitted during its application, it is then reacted in atmosphere to form nitrogen oxides. This third source is attributed to the reaction of atmospheric nitrogen, N 2, with radicals such as C, CH, and CH 2 fragments derived from fuel, [26] rather ...
Although two-way converters on gasoline engines were rendered obsolete in 1981 by "three-way" converters that also reduce oxides of nitrogen (NO x), [4] they are still used on lean-burn engines to oxidize particulate matter and hydrocarbon emissions (including diesel engines, which typically use lean combustion), as three-way-converters require ...
Staged combustion is a method used to reduce the emission of nitrogen oxides (NO x) during combustion. There are two methods for staged combustion: air staged supply and fuel staged supply. Applications of staged combustion include boilers [1] and rocket engines. [2]
Unfortunately, the production of nitrogen oxides (NO x) increases at high temperatures. The goal of EGR is thus to reduce NO x production by reducing the combustion temperatures. In modern diesel engines , the EGR gas is usually cooled with a heat exchanger to allow the introduction of a greater mass of recirculated gas.
The 1999 Gothenburg Protocol to Abate Acidification, Eutrophication and Ground-level Ozone (known as the Multi-effect Protocol or the Gothenburg Protocol) is a multi-pollutant protocol designed to reduce acidification, eutrophication and ground-level ozone by setting emissions ceilings for sulphur dioxide, nitrogen oxides, volatile organic ...