Propane-oxygen mixtures

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...

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]). 

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.)...

Figure 2 shows a T -p diagram for a propane-oxygen mixture of stoichiometric composition introduced into a batch reactor at an initial temperature T and initial pressure p. First of all, it must be observed that this diagram is very different from that shown in Figure 1, for a H2-O2 mixture. 

Figure 2 Pressure-temperature diagram of a propane-oxygen mixture.

This section presents a summary and comparison of four different projects carried out at Leverhulme Centre for Innovative Catalysis, University of Liverpool, UK on propane (amm)oxidation over Mo-V-Sb-Nb mixed oxides, V- and W-modified Keggin structure HPCs and Ga exchanged H-ZSM-5. These three examples represent the main groups of catalytic materials for propane oxidation to acrylic acid (see Section 13.3). The results, which will be discussed here, on the effect of the different redox and acid-base properties on the reaction, aim at bringing further insight into the catalytic transformation of propane. Introduction of steam or ammonia to the propane oxygen mixture over some of the catalysts is demonstrated to be a crucial parameter for more selective reaction. 

Addition of a base, such as ammonia, to propane-oxygen mixture (propane ammoxidation over Ga/H-ZSM-5) has a significant effect by enhancing the formation of valuable products (propene, acetonitrile, and acrylonitrile) over total combustion (Table 13.14) [105]. However, acetonitrile (C2 molecule) prevails over acrylonitrile (C3 molecule) in a similar manner as acetic prevails over acrylic acid in propane oxidation over HFGs. The increase in Si/Al ratio, meaning the reduction of the number of Brpnsted acid sites, benefits the selectivity to propene and acrylonitrile at the expense of acetonitrile. COx selectivities are not sensitive either to change in acidity or Ga content, which could suggest that those are... 

Although the existence of the NTC region and, respectively, cool flames in the oxidation of very rich methane—oxygen mixtures has not yet been demonstrated, this phenomenon was shown to take place for rich (up to [C3Fl8]/[02] = 23) propane—oxygen mixtures (Fig. 8.16) [165]. 

In the absence of works devoted to the kinetic modeling of the gas-phase oxidation of rich propane-oxygen mixtures at moderate temperatures (T < 800 K) and high pressures (P > 10 atm), it is worth mentioning, apart from the above works, the simulation results for similar ranges of parameters 1 < P < 10 atm, 900 < T < 1200 K, and 0.15 < < > < 4 [247]. 

Vedeneev VI, Romanovich LB, Bacevich VY, Arutyunov VS, Sokolov OV, Parfenov YuV. Experimental investigation and kinetic modeling of the negative temperature coefficient of the reaction rate in rich propane-oxygen mixtures. Russ Chem Bull 1997 46 2006-10. 

Figure 10.27 compares pressure wave amplitudes (overpressures) resulting from an underwater TNT explosion (line 1) and a propane + oxygen mixture detonation (curve 2 - at Po = 0.4 MPa, curve 3 - at Po = 0.1 MPa). The dashed vertical lines show gas cavity boundaries. 

Figure 10.28 compares pressure impulses resulting from a TNT underwater explosion (1) and a propane + oxygen mixture detonation (2) performed under... 

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