Yellow flames

Combustion behavior differed in some respects between continuous and instantaneous spills, and also between LNG and refrigerated liquid propane. For continuous spills, a short period of premixed burning occurred immediately after ignition. This was characterized by a weakly luminous flame, and was followed by combustion of the fuel-rich portions of the plume, which burned with a rather low, bright yellow flame. Hame height increased markedly as soon as the fire burned back to the liquid pool at the spill point, and assumed the tilted, cylindrical shape that is characteristic of a pool fire. 

Perchlorates are known for most metals in the periodic table.The alkali-metal perchlorates are thermally stable to several hundred degrees above room temperature but NH4CIO4 deflagrates with a yellow flame when heated to 200° ... 

When the flame is lit, adjust the gas flow and oxygen flow so that the flame is blue with an inner light-blue cone. A yellow flame is too cool and needs more oxygen. Your teacher may have additional directions on the operation of the Bunsen burner. 

The yellow flame of traditional oil burners is often surveyed by flame guards that react on the visible emission. More modern oil heaters use blue-burning flames. There, the carbon black of the combustion process is redirected to the combustion area for a more complete combustion, thus giving higher efficiency. With the reduced carbon black their yellow emission in the visible also vanishes, leaving an almost invisible flame, see Fig. 5.44. For these blue flames surveillance based on UV emission is preferable... 

You ll get a wavy yellow flame, something you don t really want. But at least it ll light. Now open the air collar a little. The yellow disappears a blue flame forms. This is what you want. 

Conventional flame retention burners create a yellow flame, while... 

For premixed fuel-air systems, results are reported in various terms that can be related to a critical equivalence ratio at which the onset of some yellow flame luminosity is observed. Premixed combustion studies have been performed primarily with Bunsen-type flames [52, 53], flat flames [54], and stirred reactors [55, 56], The earliest work [57, 58] on diffusion flames dealt mainly with axisymmetric coflow (coannular) systems in which the smoke height or the volumetric or mass flow rate of the fuel at this height was used as the correlating parameter. The smoke height is considered to be a measure of the fuel s particulate formation and growth rates but is controlled by the soot particle bumup. The specific references to this early work and that mentioned in subsequent paragraphs can be found in Ref. [50],... 

Na+ produces a bright yellow flame in a flame test. 

When Na reacts with O2 at high pressure and temperature, Na202 is decomposed to form Na20. A luminous yellow flame is formed when Na is heated in a flame as a result of emission of the characteristic D-Une at 588.997 and 589.593 nm. 

YELLOW AMBER (Organic resin) Gives a yellow flame. 

The difficulty in producing a good blue flame stems from several important considerations. Firstly, impurities in the chemicals present in the firework tend to produce yellow flames, which detract from the blue secondly, coloured flames follow similar physico-chemical phenomena but operate in different regions of the spectrum. Consequently the copper salts (that are normally utihsed for the production of blue stars) decompose thermally to produce a variety of emissions that radiate from about 325 to 660 nm i.e. from green, blue and violet to orange-red) simultaneously polluting the pure blue flame which appears in the 400 to 455 nm region. 

Yellow flames for lances may be derived from compositions based on sodium nitrate or sodium oxalate, together with magnesium as fuel and a binder such as linseed oil. 

The yellow flame colour is due to atomic emission from sodium where the spectrum is dominated by a broad emission centred on 590 nm (the resonance transition is that from the ground state to the lowest energy excited state in absorption and the reverse will apply in emission). 

Lines due to Mg atomic emissions and to emissions from gaseous MgO molecules can also be detected in most yellow flames based on Mg as fuel. 

Figure 10.4 The combustion process in lance (or similar firework) yellow flames.

Colorless gas pungent suffocating odor human odor perception 0.5 mg/m hquefies by compression at 9.8 atm at 25°C, or without compression at -33.35°C (at 1 atm) sohdifies at -77.7°C critical temperature and pressure, 133°C and 112.5 atm, respectively vapor density 0.59 (air l) density of liquid ammonia 0.677 g/mL at —34°C dielectric constant at —34°C is about 22 extremely soluble in water solution alkaline pKa 9.25 in dilute aqueous solution at 25°C the gas does not support ordinary combustion, but bums with a yellow flame when mixed in air at 16— 27% composition. 

Table 7.7 gives some data on flame temperatures obtained by Shimizu for oxidizer/shellac mixtures. Sodium oxalate was added to yield a yellow flame color and permit temperature measurement by the "line reversal" method [11]. 

Yellow flame color is achieved by atomic emission from sodium. The emission intensity at 589 nanometers increases as the reaction temperature is raised there is no molecular emitting species here to decompose. Ionization of sodium atoms to sodium ions will occur at very high temperatures, however, so even here there is an upper limit of temperature that must be avoided for maximum color quality. The emission spectrum of a yellow flare is shown in Figure 7.2. 

Thus there was for him nothing small or great in Hature. Every phenomenon embraced for him an endless diversity of factors, and in the yellow flame of an ordinary alcohol lamp whose wick was sprinkled with salt, he saw the possibility of accomplishing the chemical analysis of the most distant stars (2). 

Will bum with yellow flame in kerosene burners... 

CA 71, 103746 (1969) claim a match-ignitable, tacky compsn for use in flares, signals incendiaries. Example compsn is made by mixing Mg, AN, Napalm B with an acrylonitriline/ acrylic acid/Me-methacrylate copolymer. It burns with a bright yellow flame... 

Note C If the carbonaceous material is consumed slowly, stir it occasionally with a Pt wire. The presence of coal may be confirmed during this operation, as coal usually burns with a yellow flame and with a gpod deal of smoke of characteristic odor... 

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