The Branching Chain Explosion Upper and Lower Limits

The Branching Chain Explosion Upper and Lower Limits 

The model presented for a thermal explosion predicts that for a reaction mixture of fixed composition and fixed initial temperature, there will be a critical pressure above which explosion will occur and below which a normal stationary reaction will take place. The relation between the critical pressure and temperature is given by a modified Arrhenius equation with a negative temperature coefficient [Eq. (XIV.3.8)] which is 

Systems showing the characteristic of a branching chain explosion (e.g., oxidation of P4, PH3, NH3, H2, etc.) exhibit critical explosion limits of the 

The actual rate of reaction as a function of total pressure at fixed composition and fixed temperature is illustrated in Fig. XIII.3. In the draw- 

It is generally found that the first explosion limit of a branching chain is shifted to lower pressures by the decrease of surface/volume ratio (for example, a system becomes more explosive in larger vessels) or by the addition of an inert gas (for example, N2 or Ar). While the surface/volume behavior is similar to that found in thermal explosions, the effect of added 

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