Abstract
This paper reports on dynamic response of a large size flare stack supported by tower for a 300, 000ton/year ethylene plant. Oscillations of the structure due to wind, at Strouhal number from 0.1 to 0.4, are measured. The aerodynamic stability of this structure is better than that of a circular cylinder type stack. Earthquake responses of the large size flare stack are computed by means of the modal analysis for multi-degree mass-spring system. Oscillation due to gas discharges through the stack may be increased in proportion to rate of gas, and a small whipping is observed between burner part and top of the tower. However, the oscillation is not large as compared with that caused by the wind or the earthquake.
