Thermal analysis on batch pipelining of cold and hot crude oilwith different temperatures

Key words:  crude oil  batch pipelining  unsteady temperature field  thermal behaviors  critical temperature

Abstract:

A mathematical model describing batch pipelining of cold and hot crude oil was developed. The hydraulic system was simplified as quasi steady and the unsteady thermodynamic system was studied. The thermal characteristic equation was solved to obtain the non-steady-state oil flow temperature in the tube by finite difference method. The thermal conductivity equation was solved to obtain the pipe outside non-steady-state temperature field using finite element method and finite difference method. A typical operation case was simulated by the computer program and the simulation results were analyzed. The simulation results indicate that when periodic transportation is formed, the thermal behaviors are nearly periodic. For each period, generally inverse behaviors are shown between the process of cold batch displacing hot batch and the process of hot batch displacing cold batch. In batch pipelining of cold and hot crude oil, when head of the hot batch just reaches the next station, its temperature comes to its lowest point, which is the critical temperature for safe transportation. This temperature should be at least above the oil 's pour point for safety operation.