Rotary Calciner

CORECO® Rotary Process Furnaces are used for processing spent catalyst material containing moisture, carbon and organic contaminants. These rotary retort furnaces are available in five standard models having capacities ranging from 100 to 1,000 pounds per hour of spent catalyst.  Actual processing rates will be dependent on catalyst carrier type and size, concentrations of moisture, carbon and organic contaminants, and the degree of penetration of the carbon and organics into the pores of the catalyst carrier material.

CORECO® Rotary Process Furnaces for catalyst reclamation are designed to oxidize the carbon and organic contaminants on the spent catalyst within the rotary retort. An external thermal oxidizer is not required to achieve air quality compliance in most applications. A typical pollution control system for our catalyst reclamation system includes a cyclone and baghouse for particulate removal and a packed bed scrubber if the spent catalyst has sulfur-bearing or halogenated compounds.

The Model CA-2448 Rotary Retort Furnace shown at left was designed to process up to 1,000 pounds per hour of spent catalyst. EnviroAir provided a complete system including the pollution control equipment, barrel dumping station, and input screw conveyor and bucket elevator.

Functional Description of Rotary Calciner

Spent catalyst is fed into the input hopper (A). The input screw feeder (B), which is sealed against the input end of the rotary retort (C), feeds the spent catalyst at a constant rate into the rotary retort. In the rotary retort, the spent catalyst is heated to a setpoint temperature up to 1,700°F. The rotary retort is indirectly heated by burners (E), firing outside the rotary retort inside the furnace section (D). There is no flame impingement on the catalyst that could result in oxidation of the precious metals being reclaimed.

Flights or lifters inside the rotary retort repeatedly mix, lift and drop the spent catalyst. As the heated catalyst contacts the air above the catalyst bed, moisture on the catalyst is evaporated and carbon and organic contaminants on the catalyst are oxidized. The processing rate will be dependent on catalyst carrier type and size,  concentrations of moisture, carbon and

The air required to remove moisture and oxidize the carbon and organic contaminants on the catalyst enters the rotary retort through a connection provided on the screw feeder. An automatic valve controls the amount of air entering the rotary retort as required to maintain the setpoint oxygen concentration (typically 10%) in the rotary retort exhaust gases.

The processed catalyst material exits the rotary retort and drops through a discharge chute into the rotary cooler drum (H). In the rotary cooler drum, the catalyst carrier material is cascaded repeatedly. Heat from the catalyst material is transferred to the cooling air flowing through the cooling drum in the opposite direction of the material flow (counterflow). The temperature of the catalyst material leaving the cooling drum will be approximately 10 to 30°F above ambient temperature.

Fines in the catalyst material are filtered through a screen at the leaving end of the cooling drum and are collected in the fines hopper (I).  The larger catalyst material flows over the fines screen and exits the end of the cooling drum (J) where they can be collected in a container or transferred by a conveyor. An exhaust fan draws the dust-laden cooling air from the cooler transfer hood (G), along with the exhaust gases from the rotary retort exhaust hood (F).