Evaluation of Liquid Cargo Tank Overpressure.

摘要

The phenomenon of cargo tank overpressure during transfer operations was analyzed and analytical models describing tank pressure rise during transfer operations were validated with scale model experiments. Factors examined affecting tank pressure were cargo properties, transfer rates, tank characteristics and vent system design. Findings indicate that typical vent systems employed today have adequate capacity for venting gas but inadequate capacity to vent liquid after the tank becomes liquid full. Furthermore, it appears that tank failure is inevitable for the case of liquid overfill unless loading rate(cu-ft per sec) to vent area (sq-ft) ratios are kept below 6ft/sec. Currently, most transfer operations exceed this value with tank failure expected less than one minute after the tank becomes liquid full. A method to evaluate the adequacy of existing cargo tanks against the overpressure hazard is presented. (Author)