DepoWax is a compositional multiphase wax deposition simulator. Being fully integrated into PVTsim the user may take full advantage of the fluid handling in PVTsim and the thermodynamic wax module.
Wax appearance temperature and wax amount can be tuned up in the wax module prior to initiating a wax deposition simulation.
With the fluid properly characterized, all the user has to input is pipeline geometry (xy-coordinates, inner diameter, roughness, ambient temperature, and insulation) inlet P&T and inlet flow rate.
Default values are automatically set up for remaining properties as for example section lengths, wax diffusion coefficients, and laminar film thickness, but the user also has the option to influence parameters.
To properly account for the heat of phase transitions (evaporation, condensation and solidification) the temperature profile in the pipeline is determined by carrying out PH (Pressure-Enthalpy) flash calculations.
Two deposition mechanisms are considered:
- Molecular diffusion.
- Shear dispersion.
Wax deposition from the gas phase may be considered. The influence on the viscosity of wax particles suspended in the oil phase is considered via a shear rate dependent (non-Newtonian) viscosity model. The influence of wax inhibitors on the viscosity may also be accounted for. The program offers the choice between four different methods for calculating the heat transfer coefficients.
The simulation results give information about development with time in pressure drop, temperature profile, and position and thickness of deposited wax. The Mukherjee-Brill pressure drop model is used to simulate liquid holdup and pressure drop.
The wax deposition model is well suited for field studies as well as test loops.
Being fully compositional DepoWax is particularly suited for pipelines with multiple inlets.