Analysis on the effects of high expansion foam on evaporation rate of the LNG

Abstract

Hazards of low temperature liquid pool generated by leaked Liquefied Natural Gas (LNG) during transportation can be eased through covering of high expansion foam (HEF). In this study, sixteen cases of bench-scale tests, covering liquid nitrogen (LN2) with HEF, designed by orthogonal principle were conducted to investigate the effects of utilized HEF on the LNG liquid pool's evaporation rate. Liquid nitrogen was substituted for LNG due to the flammability of LNG. Minor discrepancy exists between thermal parameters of LN2 and LNG. Thus, the validity of the substitution can be guaranteed. Sequence of importance of each influence factor can be obtained by analyzing the evaporation rate as: foam solution mixing ratio of C > foam thickness B > supply pressure A > foam addition method D. The optimal values of each factor are A1 = 0.5 MPa, B2 = 1.0 m, C2 = 6% and D1 = one-time addition respectively. It implies that the optimal solution should be A1B2C2D1. The conclusion on the effects of each factor on evaporation rate analyzed by variance analysis is similar to the results mentioned above. Through regression analysis, significant differences were in evaporation rate at different levels of water pressure as well as foam thickness, and distinct interaction was observed between supplying pressure and foam thickness.