Study on Large Flare Stacks (Part 2): —On Radiation Characteristics of Flame—

Abstract

The burning characteristics of flame, radiated heat intensity on the ground surface, and the temperature of the structure are measured, and the radiation characteristics of flame of a large size flare stack is investigated in this paper. The flame length and diameter are increased with Mach number of waste gas flow, especially, the flame length L is related with L=0.72×103(U/Uc)D (U/Uc=Mach number, D=Diameter of flare burner), but the flame diameter is not expressed by a linear relation to Mach number. The measured value of flame length is 1/2~1/3 times the value obtained by G.R. Kent. The radiated heat intensity on the ground surface may be calculated by the equation of point heat source concentrated at the center of a flame and the fraction of radiated heat at X≤100m (X=Distance from flare stack) is smaller than that of X≥100m. In case of X≥100m, the fraction of radiated heat ε is expressed by ε=0.048√M (M=Molecular weight of waste gas). The temperature of structures, in the burning conditions, is nearly equal to the normal temperature, from the ground level to a height of EL. 110m, due to a shelter of platform installed at EL. 110m. When the fraction of radiated heat is constant, the temperature of platform may be estimated by the equation of heat radiation from the surface of an idealized ellipsoid flame. © 1971, The Japan Petroleum Institute. All rights reserved.