Study on Modification and Sulfur-Resistance Characteristics of Dolomite Catalysts over Wash Oil Catalytic Cracking

The 0.5% Ni/1% Fe–dolomite catalyst and 1% Fe–dolomite catalyst were used to explore the wash oil catalytic cracking process on a fixed-bed reactor. The experimental results were evaluated by yield distributions of gas, liquid, and solid phases; gas composition distributions; and component varieties of cracked oil. Catalysts were characterized by X-ray diffraction (XRD), thermogravimetric analysis (TG), and an automatic sulfur analyzer. Cracked oil was analyzed by gas chromatography–mass spectrometry (GC–MS). XRD analyses revealed that fresh 0.5% Ni/1% Fe–dolomite catalyst had Ni–Fe and NiO crystal phases, while the used catalyst had CaS and NiS phases when there were sulfur-containing compounds with simple structures in the wash oil. TG results showed that H 2 S contributed to the heavy aromatics adsorption on catalyst, and aggravated carbon deposition. GC–MS showed that cracked oil become lighter as a result of acenaphthene cracking into alkanes, biphenylene, and pyrolysis gas. In addition, catalytic cracking of sulfur-containing compounds did not affect the contents of other liquid components.