2019 EJRNL PP LUIGI RAIMONDI 1.pdf
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Terbatas Suharsiyah
» ITB
Terbatas Suharsiyah
» ITB
In the transport of gas-liquid mixtures, where the amount of liquid condensate is low, a stratified flowpattern is predicted by mechanistic two-phase flow models. In this case, the momentum balance between liquid and the gas phases is the key relation for the calculation of the steady state flow equilibrium
and the existing liquid hold-up. The latter value is particularly important at low production rates for
pipelines with a large number of upward and downward inclined pipe segments (making V shaped
sections) where liquid can easily accumulate in the lower parts. The error in predicting the liquid inventory has critical consequences on the evaluation of the total pressure drop along the pipeline. The
results obtained from steady state simulation can be far from reality or, at least, cannot be reproduced by
a dynamic simulation of the same operating conditions. These topics are analysed using a multiphase
flow simulator developed by the author (XPSIM, eXtended Process SIMulation) which can perform
compositional and fluid-mechanical analysis at the same time. Steady state and dynamic simulations are
developed for the Ormen-Lange pipeline (about 120 km long): large differences are found between the
steady state and dynamic solutions