Adsorption Desulfurization of Actual Heavy Crude Oil Using Activated Carbon

Abstract

The strict new regulations to reduce the sulfur content of fuel require new economical and efficient ways to remove the sulfur from the organic sulfur components. In the current work, sulfur was removed from the actual crude oil containing 2.5 wt.% from southern Iraq, specifically the Halfaya Oil Field was studied using adsorption desulfurization with activated carbon (AC). The effects of different operating conditions, including the dose of AC (0.2-1.0 gm), time (15–120 min) and temperature (30–50°C) were investigated. The best operating conditions were obtained as 0.8 gm AC, 90 minutes and 50℃, respectively. Langmuir, Freundlich and Temkin isotherm models were implemented. The steady data were best denoted via Temkin models with correlation coefficient (R2= 0.974). The kinetics sulfur components on activated carbon were examined by using pseudo-first order, pseudo-second order kinetics models and Intra-Particle diffusion. The adsorption process can be well described by pseudo-first order adsorption kinetic model with correlation coefficient (R2 = 0.9552). Thermodynamic parameters, which include Gibbs Free Energy (ΔGo), Enthalpy (ΔHo) and Entropy (ΔSo), were determined in the present research and showed that the adsorption of sulfur components on activated carbon is spontaneous, endothermic and increases the randomness of the sulfur compounds on the surface of the adsorbent. The content of sulfur in the treated crude oil was reduced from 2.5% to 1.8% corresponding to a desulfurization efficiency of 28%.