Research on the aromatics enrichment and solid particles removal during slurry oil fluidized thermal conversion

Abstract

Fluidized thermal conversion technology can facilitate the high-value utilization of slurry oil because of its high flexibility, strong adaptability of raw materials, high liquid yield, and high decarbonization rate. Herein, the thermal conversion of slurry oil using silica sand and an FCC catalyst as heat carriers was investigated by a fluidized bed reactor. The results demonstrated that at 500 °C, silica sand produced cracking oil and gas yields of 85.54 and 1.24 wt% respectively. Correspondingly, the oil and gas yields over the FCC catalyst were 72.53 and 4.70 wt%, respectively, which indicated that the FCC catalyst effectively promoted the thermal conversion of slurry oil. Moreover, the yields of main gas products H2, CH4 and C2–C3 increased significantly from 1.86, 6.59, and 2.33 mL/g (over silica sand) to 19.01, 13.16, and 20.84 mL/g (over the FCC catalyst), respectively. Fluidized thermal conversion was found to effectively cause the enrichment of the aromatic components of slurry oil by FTIR analysis in conjunction with GC-MS. The mass ratio of two–five-ring aromatics obtained via the FCC catalyst (86.53 wt%) was higher than that via silica sand (77.42 wt%). Upon using the FCC catalyst twice in succession, the yield of each cracking product remained nearly unchanged. However, the cracking oil yield increased from 73.79 wt% to 77.31 wt% with further use of the FCC catalyst, implying that the activity of the FCC catalyst decreased. Fluidized thermal conversion facilitated the removal of solid particles from slurry oil. The solid particle removal rate by the FCC catalyst was ∼3% higher than that by silica sand.