Numerical simulation and validation of pressure transfer mechanism between anvil and pyrophyllite block in high pressure high temperature cubic press

Abstract

In High Pressure High Temperature (HPHT) cubic press, the pressure needs to be transmitted to the carbon metal catalyst system through different combination of material interfaces called the supercell. The supercell structure consists of the carbon metal catalyst system enclosed within a graphite heater surrounded by a thermal and electrical insulators. The pressure transmission to the pyrophyllite block which forms the outer envelope of the supercell is essential to ensure the pressure buildup inside the system. The understanding of this pressure transfer, however, is affected by the inability of using traditional monitoring methods due to extreme operating conditions. This requires use of Finite Element Method in order to gain in-depth understanding of the pressure transfer mechanism. In this work a novel finite element framework is used to analyze the pressure generation at the anvil pyrophyllite interface system and pressure transfer through the pyrophyllite. Modelling of Pyrophyllite requires use of Lagrangian elements which distort at high pressure conditions due to its elasto-plastic behavior. To overcome excessive element distortion, local re-meshing needs to be done which not only increases the computational effort but also leads to inaccurate results. This work proposes to use the Coupled Eulerian Lagrangian (CEL) technique to model anvil system where pyrophyllite is modelled using Eulerian elements and anvil is modelled using Lagrangian elements. This solves the issue of mesh distortion as Eulerian elements are fixed in space. Mohr-Columb criteria is used to capture the elasto-plastic behavior of the pyrophyllite. Pressure at the center of the pyrophyllite block is compared with experiments and an excellent match with error less than 1.6 % between the results is observed.