Kinetics of dry flue gas desulfurization at low temperatures using Ca(OH)(2): competitive reactions of sulfation and carbonation

The kinetics of the sulfation and carbonation reactions of the sorbent Ca(O H)(2) were investigated in an isothermal packed-bed reactor for the applica tion to the flue gas desulfurization process at low temperatures. The react ion temperature was analyzed at three levels: 55, 65 and 75 degreesC; the r elative humidity in the range between 40 and 70% and the sorbent load in th e bed ranging from 200 to 600 mg. The experimental SO, breakthrough curves obtained were simulated and fitted to kinetic models according to least-squ ares minimization procedures by means of a commercial package for solving s ystems of PDEs. The sulfation and carbonation kinetics were described by a two parameters non-ideal adsorption model, considering a scheme of simultan eous reactions. The influence of the temperature and the relative humidity, was fitted by the kinetic parameters. The sorbent utilization profiles alo ng the bed for sulfation and carbonation were also simulated, being the con ditions at the inlet of reactor a good estimation of the sorbent activity a t conditions prevailing in low-temperature desulfurization processes. (C) 2 001 Elsevier Science Ltd. All rights reserved.