ياشار دولتي

Due to the increasing energy deman‎d an‎d the reduction of hydrocarbon fuel resources, the use of heavy an‎d sour oil feedstocks has become inevitable. The presence of sulfur compounds in these fuels, in addition to their corrosive effects, causes the release of environmental pollutants. One of the effective methods for sulfur removal is two-stage oxidative desulfurization using hydrogen peroxide oxidant an‎d acetic acid homogeneous catalyst. The effluent from this process contains water, catalyst, oxidized sulfur compounds, an‎d a small amount of fuel, an‎d the lack of catalyst separation causes environmental pollution an‎d increases operating costs. The aim of this research is to recover acetic acid catalyst from the effluent of the desulfurization process using a combined system of simple distillation an‎d adsorption based on activated alumina adsorbent. In this study, the desulfurization process was carried out on a model fuel containing dibenzothiophene, an‎d about 12% of the initial sulfur compounds were transferred to the aqueous phase an‎d oxidized. Then, the resulting aqueous phase was subjected to simple distillation to separate water an‎d acetic acid to about 70% acid an‎d 30% water. Due to the formation of an azeotrope, complete separation of water an‎d acetic acid was achieved only by surface adsorption an‎d the use of activated alumina. The results showed that this adsorbent adsorbed the least amount of acetic acid compared to other adsorbents used for water an‎d acid separation an‎d therefore was considered a suitable choice for catalyst recovery. The design of the experiments was carried out using the response surface method based on the Box-Behnken design an‎d the effective factors including temperature, adsorbent dosage, solution volume to adsorbent mass ratio, stirring speed an‎d contact time were investigated. Analysis of the results showed that water adsorption was mainly affected by contact time an‎d adsorbent dosage, while acetic acid adsorption was mainly dependent on adsorbent dosage an‎d stirring speed had a limited effect. Increasing the temperature from 15 to 45 °C led to a decrease in adsorption capacity, which indicates the exothermicity of the process. The regeneration process of γ-Al2O3 with 0.15 M NaOH solution maintained the reusability of the adsorbent, although the adsorption capacity decreased from 204.8 to 140.32 mg/g over five cycles. Kinetic study of acetic acid adsorption showed that the adsorption was very fast in the initial minutes an‎d after reaching equilibrium in about 150–170 minutes, the adsorption capacity stabilized at about 204 mg/g. The results of this study indicate that the combined method of simple distillation-surface adsorption using activated alumina is an effective solution for recovering acetic acid catalyst with multiple uses, increasing the economic efficiency of the process by the adsorbent, an‎d reducing environmental impacts.

گوگردزدايي اكسيداسيوني،پساب فازآبي،تقطير ساده،جذب سطحي،سولفون،اسيد استيك

Oxidative desulfurization, aqueous phase wastewater, simple distillation, surface adsorption, sulfone, acetic acid

yashar dolati

Dr. Shahrokh Shahhoseini