Hydrocarbon Vapor Emissions from Floating Roof Tanks And the Role of Aerodynamic Modifications

Abstract

The issue of hydrocarbon emissions from Floating Roof Tanks (FRT) has received considerable recent attention from the industry and regulatory agencies. However, the amount of emissions from a given facility and their dependence on factors such as wind speeds, nature of the stored hydrocarbon and, geometry of the tank and the floating roof are in considerable doubt.

The first purpose of the present paper is to derive a new formula for the rate of hydrocarbon emissions from FRT based upon the well established engineering practices and compare the implications of this formula with the widely employed, but empirically derived, API formulation.

The second purpose of the paper is to outline the promise of reduction in emission losses by aerodynamic modifications to an FRT and to report the results of one such modification. It is shown by the results that considerable fluid dynamic changes, which are likely to reduce the emissions significantly, are brought about by a simple aerodynamic modification.