Nitrogen Oxides NOx

Catalytic combustion is a process in which a combustible compound and oxygen react on the surface of a catalyst, leading to complete oxidation of the compound. This process takes place without a flame and at much lower temperatures than those associated with conventional flame combustion. Due partly to the lower operating temperature, catalytic combustion produces lower emissions of nitrogen oxides (NOx) than conventional combustion. Catalytic combustion is now widely used to remove pollutants from... 

Excess fertilizer and combustion processes also can increase nitrous oxide (NnO) and nitrogen oxides (NOx) in the atmosphere. Nitrous oxide is a powerful greenhouse gas, and nitrogen oxides lead to smog and acid rain. The production of fertilizers requires a great deal of energy. The use of fossil fuels to supply the thermal requirements for fertilizer production further increases emission of nitrogen compounds to the atmosphere. 

Nitrogen oxides (NOx) - thermal NOx is formed with gas as with other fuels, particularly if air preheat is practiced. There is very little fuel nitrogen compared with other fossil fuels so that the total NOx emissions are lower. 

Fluidized bed combustion boilers are often conventional boilers but with unconventional, specially designed furnace beds. Fluidized bed combustion boilers are used to burn solid fuels, such as low-grade, high-sulfur crushed coal. The benefit of this process is its ability to provide 95 to 100% combustion (depending on the reactivity of the fuel) combined with reduced emissions of sulfur dioxide (S02) and nitrogen oxides (NOx). 

Compliance with the EuroIII standards (2000) forced the fitting of Diesel oxidation catalysts (DOC) in the exhaust line [for the after-treatment of unburnt hydrocarbons (HC) and carbon monoxide (CO)]. Additionally, the exhaust gas recirculation (EGR) was adapted to reduce the engine-out emissions of nitrogen oxides (NOx). 

Yamagushi, M., Matsushite, K. and Takami, K. (1976) Remove nitrogen oxides (NOx) from nitric acid tail gas, Hyd. Proc. 55(8), 101. 

As expected from the Lewis acidity of Ti4+, the titanosilicates strongly adsorb and oxidize basic nitrogen-containing compounds with a lone pair of electrons localized on the N atom. By contrast, nitrogen oxides (NOx) and nitro compounds... 

Nitrites, inorganic Nitrogen oxides (NOx) Oxygen Peracetic acid Perchloric acid solutions Potassium bromate Potassium chlorate Potassium dichloro-s-triazinetrione (potassium dichloroisocyanurate) Potassium dichromate Potassium percarbonate Potassium perchlorate Potassium permanganate Potassium peroxide Potassium persulfate Potassium superoxide n-Propyl nitrate... 

Nitrosylsulfuric acid also is made from absorption of nitrogen oxides (NOx) in oleum (fuming sulfuric acid) ... 

Reduces potential for nitrogen oxides (NOx) emissions when compared to incineration. 

Nowadays automobile prevails across the globe as the most popular and important mode of transportation in our daily fife. About 50 million cars are produced each year, and totally over 700 million cars are being used worldwide. Thus, the application of automotive catalysts for detoxifying the pollutants, such as carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NOx) and particulate matter (PM) in the exhaust gases is absolutely indispensable in every vehicle. 

Nitrogen oxides (NOx) are removed by reaction with the reducing species present, viz. CO, H2 and hydrocarbons. The activity for NOx reduction increases in the order hydrocarbon < CO [Pg.63]

Nitrogen oxides (NOx= N02 and nitrogen monoxide NO) sources are mainly emitting NO into the troposphere. Thai, NO may be converted to N02 by reaction with hydrogen peroxy radical (H02) or with higher peroxy radicals (R02), produced from hydrocarbon oxidation. 

The choice of an appropriate model is heavily dependent on the intended application. In particular, the science of the model must match the pollutant(s) of concern. If the pollutant of concern is fine PM, the model chemistry must be able to handle reactions of nitrogen oxides (NOx), sulphur dioxide (SO2), volatile organic compounds (VOC), ammonia, etc. Reactions in both the gas and aqueous phases must be included, and preferably also heterogeneous reactions taking place on the surfaces of particles. Apart from correct treatment of transport and diffusion, the formation and growth of particles must be included, and the model must be able to track the evolution of particle mass as a function of size. The ability to treat deposition of pollutants to the surface of the earth by both wet and dry processes is also required. 

Several patents discuss the use of Raman spectroscopy to determine the properties of finished products.93 94 For reformulated gasoline, some of these properties include sulfur, olefin, benzene, volatile organic carbon (VOC), nitrogen oxides (NOx), aromatic contents, total air pollutants (TAPs), Reid Vapor Pressure (RVP), distillation properties, motor and research octane numbers, and drivability. For the octane numbers, the accuracy of the Raman method was limited by errors in the reference method. 

Heteroatoms do affect every aspect of refining. Sulfur is usually the most concentrated and is fairly easy to remove many commercial catalysts are available that routinely remove 90% of the sulfur. Nitrogen is more difficult to remove than sulfur, and there are fewer catalysts that are specific for nitrogen. If the nitrogen and sulfur are not removed, the potential for the production of nitrogen oxides (NOx) and sulfur oxides (SOx) during processing and use become real. 

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