Citation

Singhal SN, Delichatsios MA, de Ris J. Fire Safety J. 1989; 15(3): 227-244.

Copyright

(Copyright © 1989, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

Stack-enclosed gas flares are used to flare the produced gas onboard offshore vessels. This paper presents results for the heat radiated from the hot gas plume to personnel on the deck of the vessel. A sensitivity study for the effect of relevant system parameters on heat radiation level shows that the most important effect is due to the product of the flow rate and the heating value of the gas. Three case studies were conducted for low, medium, and high capacity flares. Results are discussed with respect to limiting flare capacities.The calculated heat radiation levels were compared with allowable limits for continuous human exposure specified by the American Bureau of Shipping (ABS). The maximum heat radiation levels from the flare systems of the low and medium capacity cases were found to be well below the allowable limits. The maximum heat radiation at the flaring rate of 16[middle dot]4 standard m3/s (50 million standard ft3/day) of the produced gas for the high capacity case was found to be below the allowable limit, but for 24[middle dot]6 standard m3/s (75 million standard ft3/day) exceeds the limit significantly. It is shown that for this latter case, a modification in the design of the flare stack (e.g. increasing the window area for air entrance openings) brings the heat radiation to a level close to the allowable limit. However, increasing the window area for air entrance openings would increase the velocity of the air-gas mixture, which in turn would increase the flame length and, hence, the required stack length. Excessive increase in stack length may impose problems of vessel stability.