Carbon-rich flame

In hot flames such as the carbon rich flame, the equilibrium would he on the right side. However, in the case of an excess of oxyanions (O-X) the equilibrium is shifted to the left and no free M atoms are formed. This can be corrected for by adding a metal (R) which forms still more stable oxysalts and releases the metal M again. To this aim La- and Sr-compounds can be used according to ... 

Carbon chemistry occurs most efficiently in circumstellar and diffuse interstellar clouds. The circumstellar envelopes of carbon-rich stars are the heart of the most complex carbon chemistry that is analogous to soot formation in candle flames or industrial smoke stacks (26). There is evidence that chemical pathways, similar to combustion processes on Earth, form benzene, polycyclic aromatic hydrocarbons (PAHs) and subsequently soot and complex aromatic networks under high temperature conditions in circumstellar regions (27,28). Molecular synthesis occurs in the circumstellar environment on timescales as short as several hundred years (29). Acetylene (C2H2) appears to be the... 

This occurs in the condensed phase and interferes with heat feedback from the burning gases in the flame to the decomposing polymer beneath. It also promotes the formation of a layer of char which further protects and insulates unbumed material. The smoke suppression effect may be viewed as a consequence of char promotion (that is carbon-rich particulates that would have otherwise become smoke, are locked up in the condensed phase as char). It is also likely that the very high surface area transition aluminium oxides formed during decomposition of ATH will adsorb many volatile species and fragments that could otherwise become smoke. 

Aniline.—Burns with a very smoky flame, clouds of soot being produced. Typical of many aromatic substances. i,2 Dibromoethane.—Does not burn until vapour becomes hot and then burns with a slightly smoky flame. Typical of substances rich in halogens such as cldoroform, chloral hydrate, and carbon, tetrachloride. (Note, however, that iodoform evolves copious fumes of iodine when heated in this way.)... 

Soot. Emitted smoke from clean (ash-free) fuels consists of unoxidized and aggregated particles of soot, sometimes referred to as carbon though it is actually a hydrocarbon. Typically, the particles are of submicrometer size and are initially formed by pyrolysis or partial oxidation of hydrocarbons in very rich but hot regions of hydrocarbon flames conditions that cause smoke will usually also tend to produce unbumed hydrocarbons with thek potential contribution to smog formation. Both maybe objectionable, though for different reasons, at concentrations equivalent to only 0.01—0.1% of the initial fuel. Although thek effect on combustion efficiency would be negligible at these levels, it is nevertheless important to reduce such emissions. 

Many hydrocarbon flames are luminous because of the incandescent carbon particles formed in the flames. Under certain conditions, these particles are released from the luminous flames as smoke. Smoke from hydrocarbons is usually formed when the system is fuel rich, either overall or locally. 

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