With the increasing demand for xylene in the petrochemical industry, the production of xyl...

With the increasing demand for xylene in the petrochemical industry, the production of xylene from toluene disproportionation has gained attention in recent years [Ind. Eng. Chem. Res., 26, 1854 (1987)]. This reaction,

was studied over a hydrogen mordenite catalyst that decays with time. As a first approximation, assume that the catalyst follows second-order decay,

and the rate law for low conversions is

with kT = 20 g mol/h-kg cat-atm and kd = 1.6 h-1 at 735 K.

(a) Compare the conversion-time curves in a batch reactor containing 5 kg cat at different initial partial pressures (1 atm, 10 atm, etc.). The reaction volume containing pure toluene initially is 1 dm3 and the temperature is 735 K.

(b) What conversion can be achieved in a moving-bed reactor containing 50 kg of catalyst with a catalyst feed rate of 2 kg/h? Toluene is fed at a pressure of 2 atm and a rate of 10 mol/min.

(c) Explore the effect of catalyst feed rate on conversion.

(d) Suppose that ET = 25 kcal/mol and Ed = 10 kcal/mol. What would the temperatııre-time trajectory look like for a CSTR? What if ET =10 kcal/mol and Ed = 25 kcal/mol?

(e) The decay law more closely follows the equation

with kd = 0.2 atm-2 h-1. Redo parts (b) and (c) for these conditions.