Generalized formulae for water cooling requirements for the fire safety of hydrocarbon storage tank farms

Abstract

Cooling water application on hydrocarbon storage tank farms is used to prevent fire propagation between the tanks caused by intense incident radiation on the tanks adjacent to fires. Codes and standards recommendations regarding the spacing between tanks and the cooling water application rate are vague and contradicting. This study investigates a non-traditional technique using Non-Uniform Coolant Application Model (NUCAM) and illustrates the effect of utilizing this technique on coolant and land rationalization in comparison to the traditional uniform application technique. NUCAM investigates the effect of simultaneous fire propagation and domino effect scenarios on the dimensionless incident heat flux in large storage tanks using gasoline and ethanol fires at various Froude Numbers. The cooling water application rate required for total attenuation is investigated based on the rings distribution surrounding the target tank(s) at steady state conditions.Utilizing the non-uniform cooling water application techniques saves up to 59.1% of the cooling water consumption. While the savings in land area reaches 15.6%. NUCAM results regarding single fire scenarios are utilized to develop novel generalized formulae for the incident heat flux and the cooling water application rate taking into consideration the radiation fraction, Froude Number, the relative spacing between the fire and the target tanks and the relative elevation of the target with respect to the fire base. The formulae show flexibility and reliability when applied on large storage tanks range between 42 m and 55 m in diameter. These formulae provide simpler and faster solution approach for investigating the incident heat flux and the cooling water requirements for large atmospheric storage tanks that require complicated computational power for simulation using commercial packages.