Modeling and simulation of unloading operations in petroleum product storage terminals

Liquefied petroleum products such as propane, butane, LPG and LNG are transported by ships and stored in tanks in storage terminals. These products are conveyed from the jetty by above-ground insulated pipelines to storage terminals that are typically situated 12–20 km inland. Unloading of petroleum products is energy intensive and results in excessive BOG (boil off gas) generation and pressure build up in the storage tank. In this work, a dynamic model of the unloading operation is developed to predict temperature dynamics of pipeline, pressure and inventory changes in the storage tank. This model consists of a lumped dynamic model for the storage tank coupled with a distributed parameter model for the pipeline. The model is validated using limited data collected from an operating plant during unloading of propane. Dynamic simulation results of the model are presented to indicate the trade-off that exists between the pre-cooling and unloading operating strategies.

► Dynamic model of pipeline pre-cooling and unloading of petroleum products.
► Prediction of pipeline temperature profile.
► Prediction of storage tank pressure and temperature.
► Prediction of boil-off gas generation.
► Optimal pipeline operation.