Adsorption Desulfurization of Iraqi Light Naphtha Using Metals Modified Activated Carbon

Abstract

The study aims to evaluate the removal of sulfur content from Iraqi light naphtha produced in Al-Dora refinery by adsorption desulfurization DS technique using modified activated carbon MAC loaded with nickel Ni and copper Cu as single binary metals. The experiments were carried in a batch unit with various operating parameters;  MAC dosage, agitation speed, and a contact time of 300 min at constant initial sulfur concentration 155 ppm and temperature. The results showed higher DS% by AC/Ni-Cu (66.45)% at 500 rpm and 1 g dosage than DS (29.03)% by activated carbon AC, increasing MAC dosage, agitation speed, and contact time led to increasing DS% values.  The adsorption capacity of MAC results was recorded (16, 15, and 20) mg sulfur/g MAC for AC/Ni, AC/Cu and, AC/Ni-Cu, respectively. Equilibrium isotherm study results show good fitting with Freundlich isotherm model with R² value (0.95) for AC/Ni-Cu. The kinetic study results showed R² value (0.974, 0.981, and 0.95) by pseudo first order and (0.96, 0.916 and, 0.909) by pseudo second order for AC/Ni, AC/Cu, and AC/Ni-Cu, respectively. The calculated q_e(cal) (4.337-4.79) mg/g by first order model was the nearest to the obtained q_e(exp) (5.125) mg/g by the experiments where no interparticle diffusion referring to more than one process is controlling the adsorption process of sulfur compounds by MAC.