Preparation of Fe-char catalyst from tank cleaning oily sludge for the catalytic cracking of oily sludge

In this study, a novel method was proposed that Fe-char was prepared from oily sludge and was further applied to the catalytic cracking of heavy oil in oily sludge. The char exhibited a porous structure and the inherent iron oxides were directly reduced to metallic iron (Fe°) at 900 °C after carbonization. The catalytic effects of the char prepared at 600 °C (Char600) and 900 °C (Char900) were compared in terms of oil conversion efficiency and gas yield. The oil conversion efficiency over Char900 was higher than that over Char600 at 600 °C (90.2% vs. 80.1%). Meanwhile, the polyaromatics in the oil product were cracked into monocyclic aromatics and the H2 and CO yields were increased significantly by using Char900, indicating that Fe° exhibited better catalytic performance for the cracking of hydrocarbons than iron oxides. The effects of catalytic temperatures (600-800 °C) on the performance of Char900 were also investigated. At 800 °C, the oil conversion efficiency reached the highest (95.8%) and the CO yield was 9.5 times higher than that under uncatalyzed conditions. Overall, the catalytic effect of Char900 can be attributed to the combined effects of char and Fe°. Char not only provided a porous surface for the adsorption of hydrocarbons, but also can react with moisture in the oily sludge through water gas reactions, enhancing the production of syngas. Moreover, Fe° played a significant role as a catalytic medium for promoting the hydrocarbons reforming and wate...

Source: Journal of Analytical and Applied Pyrolysis - March 12, 2019 Category: Chemistry Source Type: research