Origin of Emissions

The industrialization of the Western world was accompanied by a drastic increase in the consumption of fossil fuels. The energy stored in fossil fuels was freed mostly by flame combustion, which is the reaction between the carbon containing constituents of the fossil fuel and the oxygen of the air, according to the reaction 

Carbon dioxide and water are the main products of this reaction. However, incomplete combustion causes some emissions of unbiuned hydrocarbons, as well as intermediate oxidation products such as alcohols, aldehydes and carbon monoxide. As a result of thermal cracking reactions that take place in the flame, especially with incomplete combustion, hydrogen is formed and emitted, as well as hydrocarbons that are different from the ones present in the fuel. 

Most fossil fuels have some amount of sulfur-containing and nitrogen-containing constituents as well, that will yield some emissions of sulfur oxides - mainly SO2 -nitrogen oxides, commonly denoted as NOy but consisting mainly of NO, and a small amount of N2O. 

During flame combustion, temperatures in excess of 1700K occur. At those temperatures, the reaction between the air constituents nitrogen and oxygen is thermodynamically favored, resulting in the formation of nitrogen oxides, according to the overall reaction equation 

With fuels used in internal combustion engines, the reaction of eq 2 is the major cause of nitrogen oxides emissions. Of course, the amount of carbon monoxide, hydrocarbons and nitrogen oxides that are emitted is dependent on the detailed composition of the fuel as well as on the way the combustion is performed. But as an order of magnitude, the exhaust gas of a gasoline-powered spark-ignited internal combustion engine will have the composition shown in Fig. 1. 

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A detailed discussion of the origin of emission spectra is beyond the scope of this book but a simplified treatment is given in Chapter 21, Sections 21.1 and 21.2. 

Figure 10.24—Raman diffusion. Origin of emission bands cell geometry Raman spectrum of L-cystine.

A preliminary version of the SOFM method was also applied to a commercial oil-fired burner with a nominal capacity of 60 kW. The flames in this case were yellow and highly radiating, with characteristics (physical and visual) very different from those of the blue flames described. In particular, the nature and origin of emission spectra are expected to be deeply different dominated by blackbody radiation from soot particles, with a much smaller contribution due to chemiluminescence of excited radicals. An exercise similar to that reported in Section 15.4.4 was performed to estimate NO concentration from flame images. The NO emissions varied in the range of 53 to 94 ppm for the flames analyzed the estimation error was within 5 ppm in practically all cases, very similar in relative terms to the results shown in Figure 15.7. 

Vibrational origin of emission in the Bj state V ibrational energy (cm- ) above zero point... 

In order to define the extent of emissions from automotive brakes and clutches, a study was carried out in which specially designed wear debris collectors were built for the dmm brake, the disk brake, and the clutch of a popular U.S. vehicle (1). The vehicle was driven through various test cycles to determine the extent and type of brake emissions generated under all driving conditions. Typical original equipment and aftermarket friction materials were evaluated. Brake relines were made to simulate consumer practices. The wear debris was analyzed by a combination of optical and electron microscopy to ascertain the asbestos content and its particle size distribution. It was found that more than 99.7% of the asbestos was converted to a nonfibrous form and... 

The stopwatch technique for determining emission volume flow rate is based on measuring with a stopwatch the elapsed time for fume to rise between two known levels (e.g., Zj, Z,). For this test procedure to be valid, the test must be carried out in a region where the rising fume clearly exhibits buoyancy-dominated plume behavior. The calculation procedure depends on a good estimate of the location of the virtual origin of the plume and the heat release for the process. 

Cannon, R. E. (1998). The Gas Processing Industry Origins and Evolution, 2nd ed. Tulsa Gas Processors Association. Delucclii, M. A. (1998). LPG for Motor Vehicles A Total Fuel Cycle Analysis of Emissions of Urban Air Pollutants and Greenhouse Gases, prepared for the Propane Vehicle Council and the Propane Education Research Council, Washington, DC. 

Watanabe, H., Nagoshi, T., and Inaba, H. (1993). Luminescence of a bacterial luciferase intermediate by reaction with H2O2 the evolutionary origin of luciferase and source of endogenous light emission. Biochim. Biophys. Acta 1141 297-302. 

The origin of the rays was initially a mystery, because the existence of the atomic nucleus was unknown at the time. However, in 1898, Ernest Rutherford took the first step to discover their origin when he identified three different types of radioactivity by observing the effect of electric fields on radioactive emissions (Fig. 17.4). Rutherford called the three types a (alpha), (3 (beta), and y (gamma) radiation. 

The first reports of the observation of transient emission and enhanced absorption signals in the H-n.m.r. spectra of solutions in which radical reactions were taking place appeared in 1967. The importance of the phenomenon, named Chemically Induced Dynamic Nuclear Spin Polarization (CIDNP), in radical chemistry was quickly recognized. Since that time, an explosive growth in the number of publications on the subject has occurred and CIDNP has been detected in H, C, N, and P as well as H-n.m.r. spectra. Nevertheless, the number of groups engaged in research in this area is comparatively small. This may be a consequence of the apparent complexity of the subject. It is the purpose of this review to describe in a quahtative way the origin of CIDNP and to survey the published applications of the phenomenon in... 

While natural emissions of sulphur and nitrogen exist, over 95% of the sulphur emissions in eastern North America are of man-made origin. Natural sources of nitrogen are less well estabUshed but are estimated to be small when compared to the man-made emissions 21). The distribution of North American sources of sulphur dioxide and nitrogen oxides are shown in Figure 2. In 1980, which has served as the base period for the assessment of emissions,it was estimated that sulphur dioxide emissions were Canada - 4.8 million tonnes (metric) and the United States - 24 million tonnes nitrogen oxides emissions were Canada - 1.8 million tonnes and the United States - 20 million tonnes. The more recent trends for sulphur dioxide emissions in Canada and the emission control limits are shown in Figure 3 14). 

Coupling the motion of the mosaic cell (TLS and boson peak) to phonons is necesssary to explain thermal conductivity therefore the interaction effects discussed later follow from our identification of the origin of amorphous state excitations. The emission of a phonon followed by its absorption by another cell will give an effective interaction, in the same way that photon exchange leads to... 

While the discovery of the catalytic properties of zeolites was driven by the desire to improve industrial prcKessing, the development of emission control catalysts was necessitated by governmental fiat. The first requirement was for 90+% removal of CO and of hydrocarbons, a goal which could not be met by oxidation with base metal oxides. To achieve the required spedfications during automobile operations, it was necessary to develop supported platinum catalysts. Originally the support was alumina in pellet form. Later platinum on cordierite was used in honeycomb form, containing 200-400 square channels per square inch. 

The complex shown in Figure 3.9 [104] is luminescent in the solid state at 77 K with three emission maxima at 431,448 and 460 nm. The excitation maxima are at 305 and 370 nm. The origin of the luminescence has been attributed to intraligand transitions with contributions of charge transfer character. 

The further fate of the solvated electrons depends on solution composition. When the solution contains no substances with which the solvated electrons could react quickly, they diffuse back and are recaptured by the electrode, since the electrochemical potenhal of electrons in the metal is markedly lower than that of solvated electrons in the solution. A steady state is attained after about 1 ns) at this time the rate of oxidahon has become equal to the rate of emission, and the original, transient photoemission current (the electric current in the galvaihc cell in which the illuminated electrode is the cathode) has fallen to zero. Also, in the case when solvated electrons react in the solution yielding oxidizable species (e.g., Zn " + Zn" ),... 

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