For achieving maximum reliability, operability, and power recovery from fluid catalytic cracker (FCC) turbines, knowledge of the effect of flue-gas characteristics is important. This is particularly so because these machines are not equipped with specific control systems. The author discusses design of FCC power-recovery turbines, and examines the three parameters that have to be taken into account to achieve maximum reliability in the operation of turbines: (1) Flue-gas inlet temperature; (2) Flue-gas exhaust-temperature; and (3) Erosion resistance.