Propane oxygenation

Conversions of propane and oxygen are defined as moles of propane/oxygen reacted per mole of propane/oxygen fed. The yield of the C3 products was calculated as moles of compound formed per mole of propane... 

Table 1. Products and heats of reaction of C3-species from propane, oxygen and water...

TABLE 1.4 Combustion Equilibrium Product Composition of Propane-Oxygen ... 

Deron vel depends st rongly on the proportion of a combustible and an oxidizer in a gaseous mixture - the closer the proportion to stoichiome trie mixture, the higher is the velocity. Fig 4.14 on p 145 of Ref 5, gives velocity vs composition for propane-oxygen mixtures. As can be seen from this Fig 1, detonation stops if percentage of C Hg drops below 3.1 or exceeds 37... 

Reaction Zones. Pressure-temperature (Figure 4) for a 1 to 1 propane-oxygen mixture or pressure-concentration curves (Figure 5) at 429°C. show three regions for both the low and high temperature combustions. 

Figure 4. Regions of ignition, cool flames, slow oxidation with and without the pic darret in an equimolar propane-oxygen mixture. Bars on the boundaries represent experimental points, and numbers on these curves signify the duration of induction periods (in seconds). Numbered regions are defined in the text...

Pretreatment of Stainless Steel Reactor. Since quartz is unsuitable for fabricating an industrial reactor, we tested stainless steel (SUS 27) reactors. One of these was treated with 30% phosphoric acid solution for 12 hours at room temperature and then washed thoroughly (Reactor VII) and other was untreated and unaged (Reactor VI). Oxidations were carried out at 430°C. with a propane/oxygen mole ratio of 3 and at various flow rates. 

Figure 4. Oxygen conversion vs-J g [02] [Hs02 1/2dt Propane/oxygen = 3...

The optimum condition for hydrogen peroxide formation was concluded to be a propane/oxygen mole ratio 3, temperature of 430°-450°C., and a residence time 6-10 sec. 

Figure 6. Burning velocity as function of equivalence ratio and oxygen concentration for propane-oxygen-nitrogen mixtures at 311° K., measured by schlieren total-area burner method (79)...

What is true of the propane-oxygen reaction is also true of most other reactions The difference between AEf and AE is usually small, so the two quantities are nearly equal. Chemists usually measure and speak about AH, though, because most reactions are carried out at constant atmospheric pressure in loosely covered vessels. 

Effect of Pressure. An increase in pressure decreases the amount of energy required to cause ignition. In a mixture of propane, oxygen, and nitrogen, doubling the pressure decreases the minimum energy required to cause ignition by a factor of about 5. 

Flame processes have been widely used to synthesize nanosize powders of oxide materials. Chemical precursors are vaporized and then oxidized in a combustion process using a fuel/oxidant mixture such as propane/oxygen or methane/air [190]. They combine the rapid thermal decomposition of a precursor/carrier gas stream in a reduced pressure environment with thermophoretically driven deposi-... 

FIGURE B.2. A measured dependence of the explosion limit for a propane-oxygen mixture on pressure and temperature in a given vessel (adapted from information given in [8]). 

VIV propene to equimolar mixtures of propane + oxygen reduced the cool-flame induction period by ca. 18 % at 300 °C. Like the previous work, these results showed the importance of the conjugate alkene in the autocatalytic oxidation of propane. However, at 247 °C, the yield of cyclohexene just prior to the cool flame was < 1 % of the total products. In contrast, at temperatures above 300 °C, it becomes the major product and is formed in roughly equal amounts with hydrogen peroxide prior to a stabilized cool flame [52]. Tipper concluded that above 300 °C reaction (2) occurs to an appreciable extent until well after the initial stage of oxidation since the differential yield of the alkene (d[C H2 ]/ d [C Hj 2 ]) was > 25 % over at least a quarter of the reaction. 

Fig. 16. The pressure—temperature ignition diagram for propane—oxygen mixtures in the molar ratio 1 1. Cylindrical silica reaction vessel, volume = 30 cm. (1), (4) slow reaction (2), (5) slow reaction with pic d arret (3) normal flames (6) cool flames. (From ref. 147.)...

Fig, 17. The pressure—composition ignition diagram for propane—oxygen mixtures at 429 °C. (From ref. 147.)... 

Lucquin et al. [184—188], have tested several models which allow for fuel consumption and include degenerate branching. Their models are therefore more realistic and give good accounts of the effect of promoters and inhibitors. As yet, however, they have not identified the specific chemical reactions in the models, but they are attempting to use them to describe the observed kinetics and morphology of propane—oxygen mixtures. 

Fig. 32. The temperature—pressure ignition diagram obtained from the model for propane + oxygen mixtures in the molar ratio 2 1. (From ref. 195.)...

Fig. 33. Propane—oxygen. Molar ratio 1 1 cylindrical pyrex reaction vessel, volume 150 cm. (From ref. 119.)...

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