Approximate characteristics of a moving temperature front in a fixed-bed catalytic reactor based on a heterogeneous reactor model

The study deals with a non-stationary process of mass and heat transfer acc ompanied by a chemical reaction occurring in a catalytic reactor. The proce ss has been described by a one-dimensional continuous two-phase model of th e reactor. Based on the assumptions of the ''ideal thermal front'' in the r eactor, approximate solutions are obtained for the equations that describe the process. Relations are thus derived which define the principal properti es of the thermal front, namely, its propagation velocity in the bed and th e maximum temperature of the front. The above relations express these prope rties in terms of dimensionless numbers that characterise the chemical reac tion taking place in the reactor and the operating parameters of the vessel . The formulae derived may be useful in the design of reactors with the perio dic reversal of the feed mixture. They enable the effect to be analysed of the various operating parameters upon the propagation velocity of the therm al front and its maximum temperature, without resorting to tedious and time -consuming trial and error methods that require repeated integration of the model equations.