Abstract: The three-stage cyclone separators of flue gas in catalytic unit is important static equipment in the unit. Among them, the vertical three-stage cyclone separator is the most widely used. Its efficient operation is the guarantee of the long-period efficient operation of the equipment such as flue gas turbine and boiler. Efficiency and reliability of the three-stage cyclone separators are the concern of the industry. Research shows that singletube blowdown cone structure has higher efficiency, but engineering practices prove that its drift diameter should match the dust load, otherwise catalyst dust scale may appear easily, resulting in failure of the single tube. The use of a larger diameter blowdown cone can maintain the flexibility of single tube operation and improve its reliability, which is the key to prevent fouling and maintain the long-cycle operation of the flue gas turbine.

Key words: catalytic unit, single-tube three-stage cyclone separator, vertical type, blowdown cone, fouling