Meeting the challenges of cracking heavy residues has produced important innovations by Axens, Shaw Stone & Webster and Total in FCC reactor technology and catalyst regeneration.

Reactor technology
Key advances incorporated in the design are in the areas of feed and catalyst contacting, product vapor and spent catalyst separation, product vapor quench, recovery of liquid product from spent catalyst, and product yield flexibility. The Axens/SS&W FCC process provides yields that are unmatched in the industry.

Revamping numerous competitive FCC units has proven this fact; 2 to 8 percent improvement in gasoline yield is typically achieved. The technology also offers the capability to process a wide range of feedstocks – from gas oil through residue – in the same unit with multiple target product scenarios (maximum distillate, maximum gasoline, or maximum light olefins).

Regeneration

R2R, the two-stage catalyst regeneration design minimizes hydrothermal deactivation and is more metals-tolerant, thereby providing lower catalyst replacement costs. The Axens/SS&W design offers lower capital, operating, and maintenance costs as compared to competing technologies.

The mechanical design philosophy incorporates cold wall construction utilizing state-of-the-art refractory techniques. This results in low-cost carbon steel construction and a simpler, more reliable unit. Capital costs are minimized further by the low coke yields consistently achieved by the unit, allowing smaller regenerator vessels, lower air blower duties and lower flue gas rates.

Experience

To date, Axens and SS&W have designed 33 grassroots RFCC or FCC units. These units have achieved more than 200 years of proven commercial operation in processing feedstocks ranging from gas oils to residues.