TY - JOUR
T1 - Multicomponent Vapor-Liquid Equilibrium Measurements and Modeling of Triethylene Glycol, Water, and Natural Gas Mixtures at 6.0, 9.0 and 12.5 MPa
AU - Qvistgaard, Daniel
AU - Trancoso, Julia
AU - Solbraa, Even
AU - Danielsen, Marie Vikre
AU - Panteli, Eleni
AU - Kontogeorgis, Georgios M.
AU - von Solms, Nicolas
PY - 2023
Y1 - 2023
N2 - Triethylene glycol (TEG) is commonly used for natural gas dehydration,
and with subsea processing facilities on the rise, an increasing
interest is being shown in complex phase equilibria involving petroleum
fluids and polar compounds. In this study, examples of such phase
equilibria have been studied. New measurements for multicomponent
vapor-liquid equilibrium (VLE) of TEG/Water/Natural Gas systems have
been performed at pressures ranging from 6.0 MPa to 12.5 MPa and
temperatures in the range 15 °C to 40 °C. Two types of natural gas, a
Synthetic Gas (XCH4 =0.62) and a Real Gas (XCH4 = 0.92), were mixed with an aqueous TEG solution, with TEG weight percentages ranging from 95 wt.% to 99 wt.%. Glycol in gas (y1), water in gas (y2), and gas solubility in liquid (xNG)
were measured with relative experimental uncertainties below 32%. Since
the systems are highly associating, the Cubic-Plus-Association (CPA)
equation of state (EoS) was selected to model their phase behavior .
Different association schemes (4C, 4F, 5F, 6F and 5C) were tested for
TEG, and the classical 4C scheme is shown to perform best. The CPA EoS
performed in general terms well, considering the number of components in
the systems, the associated complexities, and high measurement
uncertainty for such low concentrations (<1 ppm) in the gas phase.
Furthermore, the content of N2, CO2, CH4 and ethane were modelled in the liquid phase at various conditions.
AB - Triethylene glycol (TEG) is commonly used for natural gas dehydration,
and with subsea processing facilities on the rise, an increasing
interest is being shown in complex phase equilibria involving petroleum
fluids and polar compounds. In this study, examples of such phase
equilibria have been studied. New measurements for multicomponent
vapor-liquid equilibrium (VLE) of TEG/Water/Natural Gas systems have
been performed at pressures ranging from 6.0 MPa to 12.5 MPa and
temperatures in the range 15 °C to 40 °C. Two types of natural gas, a
Synthetic Gas (XCH4 =0.62) and a Real Gas (XCH4 = 0.92), were mixed with an aqueous TEG solution, with TEG weight percentages ranging from 95 wt.% to 99 wt.%. Glycol in gas (y1), water in gas (y2), and gas solubility in liquid (xNG)
were measured with relative experimental uncertainties below 32%. Since
the systems are highly associating, the Cubic-Plus-Association (CPA)
equation of state (EoS) was selected to model their phase behavior .
Different association schemes (4C, 4F, 5F, 6F and 5C) were tested for
TEG, and the classical 4C scheme is shown to perform best. The CPA EoS
performed in general terms well, considering the number of components in
the systems, the associated complexities, and high measurement
uncertainty for such low concentrations (<1 ppm) in the gas phase.
Furthermore, the content of N2, CO2, CH4 and ethane were modelled in the liquid phase at various conditions.
KW - Multicomponent
KW - VLE
KW - Measurements
KW - Cubic-plus-association
KW - Modeling
U2 - 10.1016/j.fluid.2022.113660
DO - 10.1016/j.fluid.2022.113660
M3 - Journal article
SN - 0378-3812
VL - 565
JO - Fluid Phase Equilibria
JF - Fluid Phase Equilibria
M1 - 113660
ER -