Effects of expansion foam on controlling LNG vaporization rate
Conference Paper
Overview
Identity
Additional Document Info
View All
Overview
abstract
Copyright (2014) by AIChE All rights reserved. With increasing consumption of natural gas, the safety of liquefied natural gas (LNG) utilization has become a challenge that requires comprehensive studies on risk assessment in the LNG facilities with mitigation measures. The rapid vaporization after an LNG spill generates a vapor cloud, which is flammable at a concentration between roughly 5-15%v/v in the air. The LNG vapor is heavier than air and may migrate at the ground level over a long distance in a downwind direction, which increases the possibility of ignition resulting in fires. High expansion foam has been proved to be effective for mitigating vapor hazard and suppressing a pool fire. With respect to vapor hazard mitigation, high expansion foam may reduce the vaporization rate and increase vapor buoyancy. These effects have not been fully analyzed yet. In this work, a small-scale field experiment was performed to study the effect of high expansion foam on the vaporization rate of liquid nitrogen, used as a safe analog of LNG. It has been found that a foam blanket reduces convective and radiative heat flux to the pool. At the same time, the water drainage from collapsing foam adds additional heat to the pool; however, this was found to be small and negligible with the long lasting pools.
