Flames carbon monoxide-oxygen

One of the more widely studied continua is that of the carbon monoxide/oxygen flame. The intensity of this continuum (7) is closely related to the concentrations of CO and atomic oxygen ... 

Hollander was able to apply this relation to the ionization of the alkali metals Na, K and Cs in a series of carbon monoxide/oxygen flames (Fig. 3.23). 

Fig. 10b. Relation between burning velocity and hydrogen concentration in the combustible gas of a stoichiometric carbon monoxide-oxygen flame (after Sugden, 1965a).

J.E. Dove et al, Flame Propagation in Carbon Monoxide—Oxygen Mixtures, pp 570-74... 

In carbon monoxide ozone bums with a much brighter flame than oxygen. The carbon monoxide was ignited first, then ozone was admitted. Photographs of this flame are shown in Figure 2, (Compared with the carbon monoxide-oxygen and pure ozone flame. 

Catalyst activity was usually measured in a bench test assembly (Figure 1). The reactor included a preheat section containing tabular alumina just above (upstream from) the 30 cm3 of catalyst in the center of the reactor. Water was pumped by a minipump (Milton-Roy) to the steam generator. From a three-temperature profile around the catalyst bed, it was determined that the midpoint data were most useful and reliable. The analytical equipment consisted of an infrared device (Mine Safety Appliances) for carbon monoxide, a flame ionization detector (Beckman) for hydrocarbons, and a paramagnetic oxygen analyzer (Beckman). The entire assembly except for Telex printer and computer is pictured in Figure 2. 

Similar sets of reactions may readily be written down for carbon monoxide/oxygen, acetylene/oxygen, hydrogen/chlorine, methane/ oxygen, or ammonia/oxygen flames, and are subject to the same... 

An important peculiarity of this flame is that it is difficult or impossible to burn dry, hydrogen-free carbon monoxide-oxygen mixtures, and as a matter of fact the burning velocity appears to be a monotonic function of the added hydrogen concentration whether it comes from added H2 or H2O. The most reasonable interpretation of this fact is that the attack of CO must involve either H, OH, or both, and that the reactions CO -(-02- ... 

A peculiarity of the detonation wave, a spin which makes it travel in a spiral, was discovered by Bone and Fraser, who also found that if a slow flame travelling in a carbon monoxide-oxygen mixture is overtaken by a shock wave transmitted through nitrogen, the wave velocity increases from 39 to 308 m./sec. and a detonation wave starts. The measured pressures in the detonation wave are not high (20 atm. for the mixture 2H2 + O2) and agree with those calculated by Jouguet. ... 

Carbon monoxide burns with a characteristic blue flame in air or oxygen. The reaction... 

Direct-Flame Incinerators. In direct-flame incineration, the waste gases are heated in a fuel-fired refractory-lined chamber to the autoignition temperature where oxidation occurs with or without a visible flame. A fuel flame aids mixing and ignition. Excess oxygen is required, because incomplete oxidation produces aldehydes, organic acids, carbon monoxide, carbon soot, and other undesirable materials. 

The chemical reactions that occnr in flames transform an initial reactant mixtnre into final reaction prodncts. In the case of fnel-oxygen combns-tion, the final prodncts are principally water vapor and carbon dioxide, althongh nnmerons other prodncts snch as carbon monoxide may be formed, depending on the reactant composition and other factors. If the ratio of fnel-to-oxygen is stoichiometric, the final reaction prodncts, by definition, contain no excess fnel or oxygen. Theoretically, this means that partial oxidation prodncts snch as CO (itself a fnel) are not formed. In reality, partial oxidation prodncts snch as CO or OH are formed by high tem-peratnre reactions. For example, the molar stoichiometric reaction of methane is written ... 

Carbon monoxide is usually sampled as the second parameter in conjunction with carbon dioxide or oxygen. In theory, as the optimum is usually to have near-stoichiometric combustion without CO breakthrough it is the most reliable gas to sample. A problem is that although small quantities of CO usually indicate the need for additional air, they can also be caused by flame chilling and careful interpretation of results is needed. 

FIGURE 9.18 Schematic of the double-film model of carbon particle combustion, whereby carbon monoxide produced at the particle surface is oxidized to carbon dioxide in a boundary layer flame, consuming the oxygen that is diffusing toward the particle. 

Although some polymers such as PVC are not readily ignited, most organic polymers, like hydrocarbons, will burn. Some will support combustion, such as polyolefins, SBR, wood, and paper, when lit with a match or some other source of flame. The major products for much of this combustion are carbon dioxide (or carbon monoxide if insufficient oxygen is present) and water. 

---