| dc.description.abstract | The gas industry boom driven by the advancement of horizontal drilling and hydraulic fracturing technologies provides a solution to a growing demand on energy, especially clean energy. The liquefaction process reduces the volume by 600 times through converting natural gas into Liquefied Natural Gas (LNG) that promotes inter-regional trade using LNG transportation carriers and trucks. LNG vapor cloud and pool fire are two major hazards in the LNG facilities, where LNG is processed and stored in a large volume. NFPA 59A requires mitigation measures to reduce risks to a tolerable level in the LNG facilities. High expansion foam has been proved to be effective for mitigating the vapor hazard and controlling LNG pool fire, and is recommended by NFPA 11 and NFPA 471.
This work aims to experimentally study the mitigation effect of high expansion foam on LNG vapor and fire hazards. The blanketing effect on vapor hazard was conducted in a wind tunnel using liquid nitrogen, where heat radiation and convection were provided by a bulb panel and a fan. The results concluded that the blanketing effect could reduce 70% of the heat flux from radiation and convection for vaporization. The warming effect on vapor hazard was studied using liquid nitrogen with a self-constructed foam generator and a foam test apparatus. The vapor temperature was increased after the foam application. The temperature difference of vapor and foam was measured with a special design of thermocouple installation. The formation of vapor channel was studied in terms of the size and location. The foam breaking rate was investigated for tests with different release scenarios. The LNG fire control effect was studied through a large scale LNG pool fire field test conducted at Brayton Fire Training Field, College Station, TX. High expansion foam was applied to mitigate the fire after the fire was fully developed. The initial negative effect of foam application was minimized by using a new foam generator with a feature to prevent water discharge into the LNG pool. The mitigation effect was studied in terms of the mass burning rate, flame geometry, thermal radiation, burning velocity field, fire control time, and flame temperature. The foam application could reduce 75% of mass burning rate, 79% of flame length, and 97% of thermal radiation. | en |
