359.     ------.  [BRINKLEY, S. R.]  Contact Times of Continuous-Flow Reacting Systems With Volume Change.  Ind. Eng. Chem., vol. 40, 1948, pp. 303-307; Chem. Abs., vol. 42, 1948, p. 2849.

      General relation between contact time and space velocity is obtained by comparing the solutions of the Euler and Lagrange forms of the hydrodynamical steady-state equations for the composition of a flowing system that undergoes chemical reaction with accompanying volume change.  It is assumed that the reactor is isothermal and isobaric and that the flow is 1-dimensional.  This relation is applied to the calculation of contact times for particular rate laws.  An approximate formula is developed for estimation of contact times when the rate law is unknown, and the resulting error is obtained for several cases by a direct numerical comparison with the correct expressions.  These considerations apply to catalytic reactions on granular catalysts if apparent contact time is calculated from a space velocity defined as the volume of gas at the temperature and pressure of the feed gas/free vol. of the catalyst bed/unit of time.