Gas-phase reaction in a trickle-bed reactor operated at low liquid flow rates

The catalytic hydrogenation of alpha-methylstyrene to cumene is studied in a laboratory trickle-bed reactor operated at low liquid flow rates. Under this condition, wetting is not complete, vaporization of the liquid phase may occur, and reaction could proceed via liquid-solid and gas-solid catalysis, which increase the hydrogenation rate significantly. To determine and quantify the effect of the gas-solid catalyzed reaction, we propose the use of post-packing sections of increasing lengths. The inert bed acts as an absorber of the gas-phase-produced cumene. The liquid and gas effluent were monitored. Experimental global rates determined from liquid cumene concentrations varied with the post-packing length. A simple one-dimensional model developed shows that theoretical and experimental results agree well.