Analysis of Propane Thermal State in Underground Tanks Taking Into Consideration Design Issues

Preliminary note The paper presents an analysis of annual variations of temperature and the corresponding saturation pressure of saturated liquid propane in a mounded cylindrical tank used for liquefied petroleum gas (LPG) storage. A mathematical model has been established based on a finite volume method. Boundary and initial conditions have been assumed for the Croatian climate. Simulations have been performed using the commercial CFD (Computational Fluid Dynamic) code on the representative numerical example. Analysis results have been presented through diagrams. It has been pointed out that the present regulation and practice for such tanks defines too high a design pressure of 1.64 MPa for the Croatian climate and that pressure of 1.2 MPa is sufficient to ensure proper design of such vessels. Significant simplifications and savings in production process can be achieved by changing the unnecessarily high design pressure.