ANALYSIS OF PRESSURE DROP AND HEAT TRANSFER OF ANNULAR DEPOSITION TEST UNIT

Deposition of wax on the internal wall of pipelines is often regarded as a problem since
the tube diameter is reduced. Consequently, more power is needed to force the same
amount of oil through the system. In order to design efficient sub-sea petroleum
production facilities to achieve optimum production returns, it is necessary to understand
the phenomena of the wax deposition and provide prediction for the nature of deposits.
PETRONAS High Temperature/High Pressure Model Pipeline and Wax Deposition
Facility, HT/HPMPWDF, is designed and installed, to investigate and model the process
of the wax deposition. In this system, pressure drop and heat transfer are proposed as the
key parameters to model the process of the wax deposition. Experiments were carried out
to investigate and characterize the hydrothermal performance of the test section of the
system. Pressure drop and temperature variation data throughout the test section of the
deposition apparatus with varying flow condition were measured and processed
analytically. Also, pressure drop and heat transfer data were predicted based on the
available correlations. Comparison was made between the two models. For each
parameter involved in the pressure drop calculations, a parametric analysis was
performed to study its effect on the pressure drop estimation. The discrepancies between
the measured and calculated pressure drop results were justified and a realistic pressure
drop correlation was developed based on the equivalent length technique. The heat
transfer was investigated in terms of the steady state energy balance. Also, several heat
transfer correlations were used to predict the heat transfer. Comparison between the
theoretical and experimental results reveals that Sandal et. a/. correlation for the
convective heat transfer is produced the best agreement with the experimental results.
The system is proved to provide an experimental data within an accuracy of 7 % AAPE
for the pressure drop and 5% AAPE for the turbulent convective heat transfer. A steady
state thermal energy balance of 6 % AAPE is achieved. It could be concluded that the
proposed correlations have brought the system to the capability of modeling and
predicting the wax deposition formation.