Slurry oil, a residual oil generated in FCC refinery plants, has been widely used for producing needle coke, marine fuel, carbon fiber, carbon black, etc., but the impurities in the slurry such as catalyst powder, heavy metals, and carbon residue must be removed in advance. The conventional process involves a rough filtration followed by a fine filtration (two-stage), but suffered from problems such as high filtration resistance, short backwash interval, and short filter life.

Therefore, a petroleum refinery of China National Petroleum Corporation, with an annual slurry oil production of 250,000 tons, adopted our stainless-steel membrane filter in August 2019. Since then, the filtration system has been operating continuously for over 6 years. Currently, the rough filtration was cancelled, simplifying the process from two-stage to single-stage filtration and significantly reducing costs. The solid content of the filtrate has been maintained as 30 – 60 ppm, with a slurry oil yield of 93 – 98%, a backwash interval of 6 – 8 h, and a filtration pressure below 100 kPa.