Adsorptive separation by thermal parametric pumping .2. Experimental study of the purification of aqueous phenolic solutions at pilot scale

In this work scale-up concerns in adsorptive parametric pumping operation in recuperative mode are studied. An experimental study of the purification of wastewater containing 100 ppm of phenol using a polymeric adsorbent (Duolite ES861-Rohm and Haas, France) is reported. A completely automated pilot plant (column and ancillary equipment, product receivers, sampling, collector and analytical devices) is described. The plant is computer controlled enabling automatic data acquisition for temperature, pressure and flowrate. Parameters related with adsorption equilibrium, mass transfer and heat transfer resistances were determined in order to obtain basic information to simulate the process behavior. Continuous and semicontinuous top feed parametric pumping experiments were carried out in a bed with 0.09 m diameter and 1 m long which represents a scale-up by a factor of 60 relative to previous works. Optimal operating conditions yielding the maximum productivity of the bottom product (phenol concentration <1 ppm), were achieved experimentally with the following conditions: average cycle time = 4 h, ratio phi(B)/phi(T) = 2 (phi(B) = 0.27), reservoir volume Q(pi/omega) = 32.5 l, average flowrate = 0.24 l/min. Based on these conditions, after 12 cycles of operation, 105 l of treated water is obtained. Those optimal operating conditions were suggested by simulation studies presented in Part I (Ferreira and Rodrigues, 1995) of this work. Good agreement was obtained between experimental and simulated results using the complete model developed in Part I (Ferreira and Rodrigues, 1995).