Nitrogen in air

Basis for NOx Prevention. Emissions from turbines are a funetion of temperature and thus a funetion of the F/A ratio. Figure 10-20 shows that as the temperature is inereased the amount of NOx emissions are inereased and the CO, and the unburnt hydroearbons are deereased. The prineipal meehanism for NOx formation is the oxidation of nitrogen in air when exposed to high temperatures in the eombustion proeess, the amount of NOx is thus dependent on the temperature of the eombustion gases and also, to a lesser amount on the time the nitrogen is exposed to these high temperatures. 

Bagg, J. (1971). The Formation and Control of Oxides of Nitrogen in Air Pollution. In "Air Pollution Control," Part One (W. Strauss, ed.). Wiley, New York. 

Organic nitrogen is more reactive than nitrogen in air. Fuel NO formation is weakly dependent on temperature. 

The term prompt NO derives from the fact that the nitrogen in air can form small quantities of CN compounds in the flame zone. In contrast, thermal NO forms in the high-temperature post-flame zone. These CN compounds subsequently react to form NO. The stable compound HCN has been found in the flame zone and is a product in very fuel-rich flames. Chemical models of hydrocarbon reaction processes reveal that, early in the reaction, O atom concentrations can reach superequilibrium proportions and, indeed, if temperatures are high enough, these high concentrations could lead to early formation of NO by the same mechanisms that describe thermal NO formation. 

Antoine-Laurent Lavoisier (1743—1794) followed up Priestley s work by making quantitative measurements of the ratio of oxygen to nitrogen in air. At first he named the new gas highly respirable air and later, vital air. Lavoisier is often considered the father of modern chemistry ... 

The fraction of total carbon and nitrogen in air that exists in the condensed phase is highly variable. For example, the percentage of organics in particles has been reported to be as high as 12.5% of the total carbon in the Los Angeles area, while as much as 25% of the nitrogen was found in particles (Fraser et al., 1996). 

In such vessels granular or lumpy material moves vertically downward as a mass. The solid may be a reactant or a catalyst or a heat carrier. The reactor of Figure 17.28(a) was used for the fixation of nitrogen in air at about 4000°F. The heat-carrying pebbles are heated by direct contact with combustion gases, dropped into a reaction zone supplied with reacting air, and then recycled with elevators to the reheating zone. The treated air must be quenched... 

Both lamps generate ozone and oxides of nitrogen in air, hence the inner lamp area should be flushed slowly with nitrogen via G and H as described above. It should be noted however that low-pressure lamps give maximum light output at a wall temperature of 40 °C so excessive cooling in the lamp region is... 

Mass of nitrogen = Nitrogen in air + Nitrogen from reaction... 

In the consolidated form, vanadium metal and its alloys pose no particular health or safety hazard. However, they do react violendy with certain materials, including BrF3, chlorine, lithium, and some strong acids (23). As is tme with many metals, there is a moderate fire hazard in the form of dust or fine powder or when the metal is exposed to heat or flame. Since vanadium reacts with oxygen and nitrogen in air, control of such fires normally involves smothering the burning material with a salt. 

An excited aryl halide may also transfer charge to oxygen and thereby become activated towards attack by nucleophiles. The photoamination of 1-amino-2,4-dibromoan-thraquinone by rc-butylamine, in which the 4-Br atom is replaced, is supposed to proceed via direct interaction between the triplet state and the amine when the reaction is performed under nitrogen. In air atmosphere, however, it proceeds via both the T7, and SY states. From the singlet excited state and oxygen, an exciplex or collisional complex [AQ ()/ ] is formed which undergoes the animation639. 

An interesting reaction consists in the oxidation of atmospheric nitrogen in air by the agency of platinum black in the presence of potash or baryta water, whereby nitrous acid or ammonium nitrite are produced. ... 

Most borides are chemically inert in bulk form, which has led to industrial applications as engineering materials, principally at high temperature. The transition metal borides display a considerable resistance to oxidation in air. A few examples of applications are given here. Titanium and zirconium diborides, alone or in admixture with chromium diboride, can endure temperatures of 1500 to 1700 K without extensive attack. In this case, a surface layer of the parent oxides is formed at a relatively low temperature, which prevents further oxidation up to temperatures where the volatility of boron oxide becomes appreciable. In other cases the oxidation is retarded by the formation of some other type of protective layer, for instance, a chromium borate. This behavior is favorable and in contrast to that of the refractory carbides and nitrides, which form gaseous products (carbon oxides and nitrogen) in air at high temperatures. Boron carbide is less resistant to oxidation than the metallic borides. 

The mole fraction of nitrogen in air is 0.7808. Calculate the partial pressure of N2 in air when the atmospheric pressure is 760. torr. 

---