Oxyacetylene flame

Other uses of oxyacetylene flames in mill operations are in building up or hardfacing metal, lancing (piercing a hole in a metal mass), and a variety of metal cleaning procedures. A minor but interesting fuel use of acetylene is in flame spectrophotometry where oxygen and nitrous oxide are used as oxidants in procedures for a wide variety of the elements. 

Flame Cleaning Now little used as a preparatory method, flame cleaning is a process whereby an intensely hot oxyacetylene flame is played on the surface of the steel. In theory, differential expansion causes millscale to detach. In practice, there is evidence that the treatment may not remove thin, tightly adhering millscale. Also, steel less them 5 mm thick can buckle. Finally, the process can burn in chemicals deposited on the surface, causing premature paint failure. 

Oxo processes, 13 768 17 725 for amyl alcohols, 2 770-771 described, 2 36-41 major producers using, 2 29-3 It for producing odd-numbered higher alcohols, 2 1, 10 5 215-217 Oxo reaction, in higher olefins, 17 712 Oxosuccinic acid, 23 419 Oxprenolol, molecular formula and structure, 5 156t Ox-Tran instruments, 3 402 Oxyacanthine, 2 88 Oxyacetylene flame, 1 221 Oxy acids... 

Belgian Patent No 625012 It essentially consists of spraying either molten or partially molten absorbent onto a glass plate, for instance an alumina film prepared by melting and aluminium rod with an oxyacetylene flame and subsequently spraying the molten adsorbent onto a glass plate. 

The refractive index of vanadium is 3-03, the coefficient of absorption 8-51, and the reflexion capacity 57-5 per cent, for yellow light of wave-length A=5790.23 Vanadium compounds do not impart any coloration to the ordinary Bunsen flame, and do not furnish any characteristic line spectra even in the oxyacetylene flame. The flame produced between carbon electrodes consists of a reddish-purple core with a yellowish-green shell and a red edge.28... 

The second stage of reaction must involve certain combination steps, and these may be accompanied by dehydrogenation. (This is similar to the suggestion of Gaydon and Wolfhard for oxyacetylene flames.) It is not established whether these may be of the type... 

A water-stabilized electric arc was reported to have reached a temperature of 25,600° F. On the absolute scale, what is the ratio of this temperature to that of an oxyacetylene flame (3500°C) ... 

The kinetics and mechanisms of radical reactions important in combustion chemistry are best studied under conditions in which single reactions can be isolated rather than in flames where there are multiple pathways for formation and disappearance of the radicals. Reactions of C2 are of particular importance since recent laser saturation measurements in our laboratory (1) have shown that C2 a3IIu is present in oxyacetylene flames at concentrations on the order of 1016 molecules/cm3 (approximately 0.1 torr). Although concentrations of ground state C2 in flames are unknown and cannot be measured by the same technique due to spectroscopic constraints, we expect that C2 X3 g populations are at least comparable. Because of these relatively large concentrations the reactions of both species are of considerable importance in combustion chemistry. However, until recently very little was known about these reactions due to the difficulty of producing a clean source of C2 radicals. 

Figure 9.19. The 118.6 pm magnetic resonance spectrum of a low-pressure oxyacetylene flame [48]. The lines marked are due to OH, with the remaining lines due to CH. The spectra are recorded for two different polarisations (see text).

Slavin, W., and Manning, D. C., Atomic absorption spectrophotometry in strongly reducing oxyacetylene flames. Anal. Chem. 35, 253-254 (1963). 

Klein-Douwel, R.J.H. Ter Meulen, J.J. Spatial distributions of atomic hydrogen and C2 in an oxyacetylene flame in relation to diamond growth. J. Appl. Phys. 1998, 83, 4734-4745. 

Combustion synthesis of diamond films fi om atmospheric pressure oxyacetylene flame was first reported by Hirose in 1988.This technique, as shown schematically in Fig. 2h, has been demonstrated to be a potentially very important means of growing diamond (Table 1). In Hirose s experiments, linear growth rates of100-200 pmh were achieved. The results were then confirmed by Hanssen et al.l l In Hirose s experiments and most of those that followed, the oxyacetylene torch was typically run with... 

Cappelli, M. A., and Paul, R H. "An Investigation of Diamond Film Deposition in a Premixed Oxyacetylene Flame." Journal of Applied Physics 67, no. 5 (1990) 2596-2602. 

Welter and Menningen (1997) have detected both CN and OH in an oxyacetylene flame used for atmospheric diamond growth. Figure 19 shows a typical absorption spectrum from the OH radical. Both species were primarily found in the outer parts of the flame, rather than in the flame feather, where diamond is grown. They measured column densities as a function of distance from the substrate. Column densities of 2 x 10 cm to 2 x 10 cm for CN... 

To obtain a stoichiometric flame, the flow rate of the gases should be close to the ratio in the chemical reaction. For example, in the oxyacetylene flame, 2.5 moles of O2 react with each mole of C2H2. The flow rate of O2 should then be about... 

Acetylene is used in oxyacetylene flame for welding and cutting metals as an illuminant as a fuel for purifying copper, silver, and other metals and in the manufacture of acetic acid, acetaldehyde, and acetylides. It is formed when calcium carbide reacts with water. It is also obtained from cracking of petroleum naphtha fractions. 

Shear forming is typically performed cold, but in case of high-strength materials and thick components, heating is applied to reduce the roller forces. In industry, manual heating is used widely sheet is heated by an oxyacetylene flame as it is formed. However, this improvised approach has its disadvantages sheet temperature cannot be controlled... 

A few of these instruments were imported and used in the USA. But flame photometry was uncommon there until the introduction of the Beckman total-consumption nebuHzer-burner, producing a turbulent oxyacetylene flame. It was used with a high-quality silica prism spectrometer, a photomultiplier detector, and very simple electronic nullbalancing circuitry. Flame emission analysis for many elements was thus widely practised until atomic absorption equipment became available. 

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