This paper deals with the modeling and simulation of binary liquid-phase adsorption of methyl mercaptan and hydrogen sulfide from a liquid butane stream by zeolite molecular sieve 13X in a fixed bed. The model equations account for the effect of axial dispersion and the inter- and intraparticle mass-transfer resistances at isothermal operating conditions. Orthogonal collocation and Gill's fourth-order Runge-Kutta methods were used to solve the dimensionless general forms of the 4N-coupled ordinary differential equations for simultaneous adsorption of the solutes by the adsorbent in a fixed bed. The model predictions were compared to the commercial-scale plant data of an Iranian petrochemical company (Bandar Imam, Iran), and a fair agreement was observed for the fixed-bed absorber of 1.7 m in diameter and 5.06 m in height. Moreover, the influences of the bed Reynolds number, Peclet number, total inlet sulfur concentration, feed temperature, and diameter of the spherical adsorbent on the breakthrough curve were investigated.