How do you reduce NOx in a diesel engine?
How do you reduce NOx in a diesel engine?
NOx emission can be reduced by primary methods such as retard injection, fuel nozzle modification, change of compression ratio, water direct injection, water emulsification, exhaust gas recirculation (EGR) and secondary method such as selective catalytic reduction (SCR).
How can NOx emissions be reduced?
One way of controlling NOx emissions is to use low-nitrogen fuels. Another is to modify combustion conditions to generate less NOx. Flue gas treatment techniques, such as selective cata- lytic reduction (SCR) processes, can remove NOx.
How much NOx does a diesel engine produce?
Concentrations of NOx in untreated diesel exhaust are typically between 50 and 1000 ppm.
How can we reduce NOx emissions in biodiesel?
Retarding the injection to post-TDC (top dead center) lowers the peak heat release and flattens the heat release curve. It is observed that low-temperature combustion effectively reduces NOx emissions because less thermal NOx is formed.
How can I reduce my diesel emissions?
An excellent way to reduce diesel emissions is to install a selective catalytic reduction (SCR) onto your car. The job of the SCR is to convert gases from NoX to either nitrogen or water vapour. This advanced emissions control technology system adds ammonia to the exhaust gases.
What causes high NOx in diesel engines?
Q. Why are NOx gases produced? High temperature combustion of fuels where the temperature is hot enough (above about 1300°C/ 2370°F) to oxidise some of the nitrogen in air to NOx gases. This includes burning hydrogen, as it burns at a very high temperature. Comments on diesel engines are shown below.
How does ammonia reduce NOx?
The SCR process chemically reduces the NOx molecule into molecular nitrogen and water vapor. A nitrogen based reagent such as ammonia or urea is injected into the ductwork, downstream of the combustion unit. The waste gas mixes with the reagent and enters a reactor module containing catalyst.
Why do diesel engines produce more NOx?
Why do diesel engines produce more NOx than petrol engines? Diesel engines operate at a higher temperature and pressure than petrol engines. These conditions favour the production of NOx gases. The quantity depends on the volume and duration of the hottest part of the flame.
Do petrol cars emit NOx?
Among the air pollutants gasoline and diesel engines emit are oxides of nitrogen—NO and NO2, generically abbreviated as NOx. Nitrogen oxides have harmful direct effects on human health, and indirect effects through the damage they do to agricultural crops and ecosystems.
Why does biodiesel produce more NOx than diesel?
Mueller, Boehman and Martin (2009) stated that, higher bulk modulus of biodiesel leads to increased cetane number and advanced injection, which results in earlier start of combustion; this yields longer resident time and higher in-cylinder temperature which may increase NOX emission.
Does biodiesel increase NOx emissions?
Abstract: Biodiesel blends increase NOx emissions in most diesel engines. The increases of NOx can occur for multiple reasons, the relative importance of which is dependent on both the particular engine and its operating conditions.
How much does AdBlue reduce NOx?
The use of AdBlue® can cut up to 90% of harmful Nitrogen Oxide (NOx) emissions that a diesel car produces through its exhaust system following the combustion process. AdBlue® must be used in most diesel vehicles (cars, vans, trucks and buses), bought after October 2006.
How do you reduce NOx emissions from a diesel engine?
Reducing NOx Emissions from Diesel Engines. However, these catalysts can’t be used for diesel engines as diesel exhaust gases typically contain oxygen, which renders the three-way catalyst inactive. Selective catalytic reduction (SCR) is the leading method of NOx removal from diesel engine exhaust gases.
Why are three way catalysts not used for NOx control on diesel engines?
Thus, commercial diesel engines operate with lean burn combustion and contain high concentrations of oxygen in their exhaust gases at all operating conditions. For this reason, three-way catalysts are not employed for NOx control on diesel applications.
Why does a diesel engine produce more NOx than a gasoline engine?
Diesel engines operate at a higher temperature and pressure than gasoline engines, which favors the production of NOx gases. As a result, diesel engines produce more NOx emissions than gasoline engines. Exposure to NOx emissions has been associated with increased deaths from heart disease, lung disease,…
How do you remove NOx from a car exhaust?
Urea or ammonia is injected, and the NOx gases are reduced to nitrogen without the need for a catalyst. On an industrial scale, exhaust gases can be scrubbed with chemicals such as sodium hydroxide, hydrogen peroxide, or a mixture of hydrogen peroxide and nitric acid. These chemicals react with the NOx gases and removes them. Q.
