Условия пожара пролива нефтепродуктов на теплоизоляцию резервуаров

Abstract

Tanks, pipelines and other items are often made using heat insulation from mineral wool, which is made of non-organic fibers and binding to provide operational properties, including hydrophobic property related to water. However this technology does not protect from wetting by many other fluids and mineral is good in absorbing oil, petroleum products (motor oils, lubricants, solvents, anti-freezes etc.). This is why fire safety of combustible fluids spill on building structures with heat insulating layer from mineral wool is connected with possible fire spreading. In order to study conditions under which spill fire is developed along vertical structures of cylindrical oil and oil products tanks, fire tests and experiments were conducted on cold hydraulic rig. For physical modeling of the accident and spill fire, heat insulating layer gasoline and motor oil dip were used. Depending on the location of tank shell relative to heat insulating layer, fire propagation in the ventilated gap and smoldering without gap were studied. For all constructive solutions a certain heat effect was observed, but it has been indicated that concealed burning propagation is the ultimate danger. Data for the evaluation of the residual content of petroleum products in the heat insulating layer depending on the time after spill fire accident was obtained, this data is suggested to be used to forecast duration and intensity of spill fire. Factors characterizing product viscosity of petroleum product and dependence of viscosity from temperature were referred to as dominant. Signs of petroleum products distillation and rectification processes, which may accompany vertical spill fire and facilitate to the propagation of combustion of gaseous products in the top of heat insulating layer as well as combustion of heavy fractions in its lower part. Conclusions were drawn that with timely cessation of spill accident, desorption process significantly reduces fire load on heat insulating layer, but ignition hazard is present for a long time, especially in the cases when mineral wool is impregnated with viscous oil products. It was also noted, that increase in temperature during spill fire leads to the decrease in oil products viscosity, with which mineral wool is impregnated, and as a result desorption is enhanced, leakage of flammable liquid speeds up and transition of vertical spill fire into horizontal becomes more probable.