Experimental validation of a mathematical model for fixed-bed desulfurization



Porous particles of two commercially available ZnO sorbents differing in porosity, surface area, and pore-size distribution were reacted with H2S at 500 and 600°C in a fixed-bed reactor. Concentration breakthrough curves were determined by analyzing the effluent of the reactor using a gas chromotograph equipped with thermal conductivity and flame photometric detectors. The pore structure of samples collected from different positions in the reactor was analyzed by mercury porosimetry and gas adsorption to determine the variation of the average structural properties of the sorbent with the length of the reactor. The obtained experimental data were used to validate a fixed-bed desulfurization model, which employs detailed submodels for diffusion, reaction, and structure evolution in the porous sorbent particles. With the various parameters appearing in the submodels determined from independent thermogravimetric reactivity evolution experiments, the fixed-bed desulfurization model was found to be capable of providing an excellent description of the behavior of the desulfurization sorbents in a fixed-bed reactor.