Transient response of continuous-flow stirred reactors containing heterogeneous systems for catalysis or sorption

Time domain solutions are presented for the transient response of an isothermal CFSR with one-dimensional diffusion and first-order irreversible chemical reaction in catalyst particles or liquid pools of regular geometry and with mass transfer resistance at the fluid-catalyst interface. Three different cases of feed perturbations have been considered, namely, step input, impulse input and the sudden introduction of pellets into the reactor. The solutions have been derived in a general manner, without specifying the particle shape, and are in terms of characteristic functions defined for each of the three particle geometries considered, i.e. slab with sealed edges, cylinder with sealed ends, and sphere. Asymptotic solutions suitable for large Thiele parameters (gf≥3) have also been derived and are particularly convenient when the series solutions converge slowly. Experimental verification of the exact and asymptotic solutions for a specific case of absorption and diffusion in a liquid pool is presented.