Investigation to VOCs emission factors in filling gasoline into tank

An experimental system of filling gasoline into a tank was set up to investigate gasoline vapor-air mass transfer and VOCs emission factors in different operating conditions such as the height of the filling pipe exit, the speed u of the filling gasoline, and the initial vapor concentration C₀ in the tank gas space. Because the vapor-air convective transport almost dominated the vapor-air mass transfer for the upper exit, but the convective transport weakened slightly and the natural molecule diffusion would also take certain action for the lower exit, the emitting gas-liquid ratio λ and the evaporation loss rate η for the upper exit always increased with the increase of u and were always greater than that for the lower or mid exit. For the three exits, with the increase of C₀, both the discharge vapor concentration and the loss rate always increased but λ always decreased. These results were also compared with the theoretically calculated values deduced and showed by mathematical model and numerical analysis.