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The PC-SAFT equation of state (EoS) combined with the free-volume theory (FVT) recently proposed (DOI: 10.1016/j.fluid.2019. 112280) is extended in this work to simultaneously predict viscosity and some second-order derivative properties such as sound velocity and isobaric heat capacity of some petroleum and refinery gases. The PC-SAFT pure component parameters are obtained by providing the optimal description of its vapour pressure and saturated liquid density data. New FVT parameters were derived for various petroleum and refinery gases and were validated with the National Institute of Standards and Technology’s data over a wide range of temperature and pressure (up to 2,000 bars). The model is simple to incorporate into the design and simulation package such as Aspen Plus or Prosim, with average absolute deviation obtained on viscosity within the experimental incertitude (< 3%), which is appropriate for most industrial applications.
PETROVIETNAM PETROVIETNAM JOURNAL Volume 6/2020, pp 45 - 53 ISSN 2615-9902 PREDICTION OF THERMODYNAMIC PROPERTIES OF PETROLEUM AND REFINERY GASES USING PC-SAFT+FVT MODEL Luu Tra My1, Nguyen Huynh Dong1, Nguyen Huynh Duong2 Petrovietnam Manpower Training College (PVMTC) Petrovietnam Gas Joint Stock Corporation (PV GAS) Email: dongnh@pvmtc.com.vn Summary The PC-SAFT equation of state (EoS) combined with the free-volume theory (FVT) recently proposed (DOI: 10.1016/j.fluid.2019 112280) is extended in this work to simultaneously predict viscosity and some second-order derivative properties such as sound velocity and isobaric heat capacity of some petroleum and refinery gases The PC-SAFT pure component parameters are obtained by providing the optimal description of its vapour pressure and saturated liquid density data New FVT parameters were derived for various petroleum and refinery gases and were validated with the National Institute of Standards and Technology’s data over a wide range of temperature and pressure (up to 2,000 bars) The model is simple to incorporate into the design and simulation package such as Aspen Plus or Prosim, with average absolute deviation obtained on viscosity within the experimental incertitude (< 3%), which is appropriate for most industrial applications Key words: Viscosities, PC-SAFT, prediction, thermodynamic, petroleum gases Introduction The importance of gases in oil recovery operations is increasing, as evidenced in the successful use of gases such as carbon dioxide, nitrogen and their mixtures as injection gases in enhanced oil recovery The simulation and modelling using the simulation package allow to reduce capital, time and cost related to the operation of oil and gas processing units and pipeline transportation In this, the viscosity model is an important component of the package, ranging from the simulation of gas production at reservoir condition to the design and operation of pipeline transportation or petrochemical plant Although the experimental data are available for numerous petroleum gases, there is still a need for a generalised estimator that is able to predict the thermodynamic properties of molecules over a wide range of thermodynamic conditions, particularly at extreme temperature and pressure condition Simultaneous prediction of transport properties and fluid phase equilibria using equation of state is Date of receipt: 7/9/2019 Date of review and editing: 7/9 - 9/10/2019 Date of approval: 5/6/2020 still an important subject in the oil and gas industry So, the development of a thermodynamic model with good accuracy in predicting the phase equilibria and thermodynamic properties of fluids is a great importance In this paper, the applicability of the PC-SAFT+FVT model is assessed on petroleum and refinery gases PC-SAFT + FVT model In previous works, the PC-SAFT + FVT model has been proposed based on the assumption that the viscosity of real fluids could be directly related to PC-SAFT molecular parameters [1] Our model has been successfully applied to calculate the viscosity of several kinds of molecules such as alkane, cycloalkane, alcohols, aromatics and their mixtures [1, 2] In this work, we apply, for the first time, the PC-SAFT+FVT model to the calculation of the thermodynamic second-order derivative properties and the viscosity of several gases 2.1 PC-SAFT EoS The original PC-SAFT EoS is expressed as a sum of different residual Helmholtz terms [3]: ares = ahc + adisp PETROVIETNAM - JOURNAL VOL 6/2020 (1) 45 PETROLEUM PROCESSING For all gases studied in this work, they are considered as non-associative, non-polar molecules PC-SAFT EoS requires three parameters to describe these components (dispersive energy - ε/k, segment diameter - σ and segment number - m) The readers are referred directly to the original papers for more details about the PCSAFT EoS [3] All expressions used to calculate different thermodynamic properties such as heat capacity or speed of sound are explained in the references [4 - 6] In which T, M, and are temperature (K), mass molecular (g/mol) and gas viscosity, respectively; σ and m are PC-SAFT EoS hard-sphere diameter (Å) and segment number The reduced collision integral (Ω*) is calculated using Equation (4) [7] 2.2 Free-volume theory The dimensionless temperature (T*) is a function of temperature and PC-SAFT dispersive energy of pure compound, small gases: (4) The fluids’ viscosity by FVT consists of two terms [1]: (2) T* = The first term called dilute gas viscosity ( ) is expressed as [1]: The other contribution of viscosity in Equation (2) is the residual viscosity (Δη), that could be estimated based (3) 300 Methane Methane Methane Methane Methane Methane 500 Methane 500 Methane 500 500 50 1,100 1,100 900 900 1,100 1,100 700 700 900 900 500 0.5 700 300 500 0.5 0.5 100 300 1000 1000 0.05 00.05 100 0.05 0.05 1000 1000 0.5 30 30 30 1 30 1 10 100 10 100 PressurePressure (bar) (bar) 10 10 100 100 Pressure Pressure (bar) (bar) 500 700 300 500 100 300 150 300 300 450 450 600 600 150 100150 150 300 300 450 450 (g/l) 0150Density 150 300 450 Density 300 450(g/l) 600 600 150 150 300 300 450 450 Density Density (g/l) (g/l) 0.4 0.4 Methane Methane Viscosity ( mPa.s) Viscosity ( mPa.s) 2000 2000 Methane Methane Viscosity ( mPa.s) Viscosity ( mPa.s) 0.4 Methane Methane Sound Spd (m/s) Sound Spd (m/s) 0.4 Spd (m/s) SoundSound Spd (m/s) 2000 2000 Methane Methane 0.04 0.04 0.04 0.04 100 K 100 K 200 K 200 K 100 KK 100 300 300KK 200 KK 200 400 400KK 300 KK 300 500 500KK 400 KK 400 150 150KK 200 200 K 0.004 0.004 500 K 500 10 100 1000 10 100 10 100 1000 10 100 150 K 150 K Pressure (bar) Pressure (bar) (bar) Pressure (bar) Pressure 200 0.004 200 0.004 10 100 1000 10 10 (NIST 100 1000 100 100 Figure Predicted and experimental Chemistry Web Book) isobaric heat capacity, liquid density, viscosity and speed of10sound of methane Pressure Pressure Pressure (bar) (bar) Pressure (bar) (bar) 46 PETROVIETNAM - JOURNAL VOL 6/2020 100 K100 K 50 50 Pressure (bar) (bar) Pressure Pressure Pressure (bar) (bar) 50 100 K 100 K Cp (J/mol*K) Cp (J/mol*K) Cp (J/mol*K) Cp (J/mol*K) 300100 K 100 K 200 K 200 K 300 300 100 K 100 K 300 K 300 K K 200 KK 200 400 400 K 300 300 KK 500KK 500 400 K 400 K 500 K 500 K T ε k 100 K 100 K 200 K 200 K 300 100 KK 100 300KK 400 200 KK 200 400KK 500 300 KK 300 500KK 150 400 KK 400 150KK 500 K 500 K 1000 1000 150 K 150 K 1000 1000 PETROVIETNAM Table PC-SAFT+FVT model parameters for gases [9, 10] Compound Iso-butane Oxygen Carbon monoxide Carbon dioxide Nitrogen Methane Ethane ε/k (K) σ (Å) m L x 103 (Å) 205.942 113.642 89.394 151.734 89.468 150.037 189.001 3.6584 3.1759 3.1964 2.5608 3.2945 3.7042 3.5098 2.4587 1.1481 1.3699 2.5807 1.2376 1.0003 1.6364 3.4260 2.5913 5.5051 1.9059 1.6560 2.1652 3.7890 α x 103 (J m3/ mole kg) 3.9298 0.5549 0.5709 1.6735 0.9291 2.3798 2.4022 Fp Fc x 102 1.0 1.35 0.15 2.8 1.85 1.0 1.35 2.2908 1.0599 1.2044 1.6207 1.1037 0.9832 1.2336 Table The average absolute deviation (AAD) for the PC-SAFT+FVT for all of the investigated molecules Experimental data are taken from DIPPR [8] Liquid density Liquid viscosity T (K) AAD (%) T (K) AAD (%) 54 - 154 0.92 54 - 132 1.83 68 - 132 1.48 68 - 124 3.83 216 - 304 1.38 200 - 304 1.08 63 - 126 1.41 64 - 122 2.60 90 - 190 1.10 84 - 186 0.40 90 - 305 1.31 90 - 302 1.69 123 - 407 2.22 114 - 310 1.95 1000 1000 Ethane Ethane 10 10 100100 Pressure (bar)(bar) Pressure 10 10 100100 Pressure (bar) Pressure (bar) 1000 1000 1000 1000 Ethane Ethane Ethane 2000 2000Ethane 0.8 0.8 Viscosity ( mPa.s) Viscosity ( mPa.s) Viscosity ( mPa.s) Viscosity ( mPa.s) 2000 2000 Sound Spd (m/s) Sound Spd (m/s) Sound Spd.Spd (m/s)(m/s) Sound 100 K100 K 10 10 Ethane 1 Ethane 700700 1 0.1 0.1 700 700 0.1 0.1 0.010.01 400400 0.010.01 0.001 0.001400400 0.001 0.001 0.0001 0.0001 100100 0 150150300300450450600600750750 0.0001 0.0001 0.00001 0.00001 100100 0 150150 300 600600 300 450450600 450 300 0 150150300 450(g/l)600 750750 Density Density (g/l) 0.00001 0.00001 0 150150 300300 450450 600600 Density Density (g/l)(g/l) Ethane Ethane 200200 1 200200 1 Ethane Ethane 100 K 100 K 100100 10 10 600600 K K 50 50 1 50 50 1 1000 1000 100 100 200 K200 K Ethane Ethane Vapour viscosity T (K) AAD (%) 54 - 600 0.81 68 - 600 1.17 270 - 610 1.83 64 - 600 0.56 84 - 600 0.31 90 - 600 1.29 150 - 600 1.95 200 K 200 K Cp (J/mol*K) Cp (J/mol*K) Cp (J/mol*K) Cp (J/mol*K) Oxygen Carbon monoxide Carbon dioxide Nitrogen Methane Ethane Iso-butane 500500 100100 K K 200100 K 200 500500 100 K KK 320200 K 320 200 K KK 400320 K 400 320 K KK 500400 K 400500 K KK 600600 K 500500 K KK Vapour pressure T (K) AAD (%) 54 - 154 0.67 68 - 132 0.38 216 - 304 0.28 63 - 126 0.24 90 - 190 0.51 90 - 305 0.67 123 - 407 3.28 Pressure (bar) (bar) Pressure Pressure (bar)(bar) Pressure Compound Ethane Ethane 0.8 0.8 0.080.08 100100 K K 200200 K K 100 K 320100 K KK 320 200 200 K 400400 K KK 320 K 500320 K KK 500 400 400 K 600600 K KK 500 K 500 K1000 1000 600600 K K 1000 1000 100100 K K 0.08 320 K K 320 0.08 100 K 100 K 500500 K K 320 320 K K 500500 K K 200200 K K 400400 K K 200 K 200 K 600600 K K 400 400 K K 600600 K K 0.008 0.008 10 10 100100 1 10 10 100100 Pressure (bar)(bar) Pressure (bar)(bar) Pressure Pressure 0.008 0.008 10 10 100100 1 10 10 100100 Figure Predicted and experimentalPressure (NIST Chemistry Web Book) isobaric heat capacity, liquid density, viscosity and speed of sound Pressure of ethane Pressure (bar) Pressure (bar) (bar) (bar) 1000 1000 1000 1000 PETROVIETNAM - JOURNAL VOL 6/2020 47 PETROLEUM PROCESSING T ε k T T * = on the expression previously suggested [1]: ε k T* = (5) characteristic parameters of fluid according to FVT theory The FVT parameter triplet set and the Fc can be obtained by regressing to the experimental viscosity data PC-SAFT+FVT parameters regression Where the viscosity is given in mPas; R is universal gas constant (8.314 J/mol.K) and P is pressure (in bar) The liquid density (ρ, in kg/m3) is the only property yielded by the PC-SAFT L is the length parameter (in Å) which is related to the molecular size, α is the barrier energy required for self-diffusion (in J m3/(mol.Kg), and Fp is the free-volume overlap These last three parameters are 55 55 55 55 Nitrogen Nitrogen Nitrogen Nitrogen 100KK 100 200 100 100 KKK K 200 300 200 200 KKK K 300 400 300 300 400 KKK K 500 400 400 KKK K 500 600 500 500 600 KKK K 600600 K K 100 100 100100 10 10 10 10 40 40 40 40 11 1 25 25 25 2511 1 10 100 10 100 Pressure (bar) 10 10 100 Pressure (bar) 100 Pressure (bar) Pressure (bar) 100KK 100 100 100 KK K 300 300 K 300 300 500KKK K 500 500500 K K 1000 1000 1000 1000 150 150 150150 Nitrogen 300 600 900 Nitrogen 300 600 900 Nitrogen Nitrogen 300 600 300 600 900900 300 450 600 300 450 600 Density (g/l) 600600 Density (g/l) 300300 450450 Density Density (g/l)(g/l) 900 900 900900 200KK 200 200 200 KKK K 400 400 400 400 KKK K 600 600 600600 K K Viscosity ( mPa.s) Viscosity ( (mPa.s) Viscosity mPa.s) Viscosity ( mPa.s) 550 550 550550 10 100 10 100 Pressure(bar) (bar) 10 10 100100 Pressure Pressure (bar) Pressure (bar) Nitrogen Nitrogen Nitrogen Nitrogen 1000 1000 1000 1000 0.01 0.01 0.010.0111 1 10 100 10 100 Pressure(bar) (bar) 10 10Pressure 100100 Pressure (bar) Pressure (bar) Figure Predicted and experimental (NIST Chemistry Web Book) isobaric heat capacity, liquid density, viscosity and speed of sound of nitrogen 48 750 750 750750 0.1 0.1 0.1 0.1 850 850 850850 250 250 25025011 1 0.1 0.1 0.1 0.100 0 900 900 900 900 700 700 700 700 500 500 500 500 300 300 300 300 100 100 1001000 100KK 100 100 100 KKK K 300 300 300 300 KKK K 150 150 150150 K K 200KK 200 200 200 KK K 400 400 K 400 400 600KKK K 600 600600 K K Sound Spd (m/s) Sound Spd (m/s) Sound Spd (m/s) Sound Spd (m/s) 1150 1150 1150 1150 1000 1000 1000 1000 Pressure (bar) Pressure (bar) Pressure (bar) Pressure (bar) CpCp (J/mol*K) Cp(J/mol*K) (J/mol*K) Cp (J/mol*K) 70 70 70 70 Six petroleum and refinery gases and oxygen have been studied These gases have been selected to test the model due to the availability of experimental data The regression of PC-SAFT+FVT model parameters has been carried out in a sequential manner, with alternate optimisation of the PC-SAFT EoS parameters and then the correction factor (Fc) and the FVT triplet set in Equation (5) PETROVIETNAM - JOURNAL VOL 6/2020 Nitrogen Nitrogen Nitrogen Nitrogen 1000 1000 1000 1000 PETROVIETNAM were next determined by minimising a quadratic residual defined by relative viscosities Step 1: The PC-SAFT EoS parameters of petroleum and refinery gases were determined by simultaneously fitting on its vapour pressure and saturated liquid density The regression function that was used is written as: component is dictated by the availability of experimental data from the Design Institute for Physical Property Data (DIPPR) [8] (6) Step 2: Having three PC-SAFT parameters, the correction factor (Fc) of gases is fitted using their dilute gas viscosity data Three adjustable parameters (L, α, Fp) in Equation (5) were obtained by fitting the model to the saturated liquid viscosity Where NPsat and Nρliq are the number of the experimental vapour pressures and saturated liquid exp cal AAD(%) 100 density data, respectively The choice of data for each The PC-SAFT+FVT model parameters for different gases considered in this work are reported in Table Table represents the experimental data sources and deviations obtained with PC-SAFT+FVT model for pure gases For all Fobj N P sat N P sat Pcsaal t Pesxapt Pesxapt li q cal liq li q ex p li q ex p Carbon monoxide Carbon monoxide Carbon monoxide 100 K 100 KK K 100 150 150 KK K 150 200 200 200 300 KK K 300 KK K 300 400 400 KK K 400 500 500 KK 500 1000 1000 1000 100 100 100 Pressure (bar) Pressure (bar) Pressure (bar) Pressure (bar) CpCp (J/mol*K) Cp (J/mol*K) (J/mol*K) Cp (J/mol*K) N exp data 115 115 115 N l iq 10 1010 70 7070 11 25 2525 11 10 100 1010Pressure (bar) 100 100 Pressure (bar) Pressure (bar) 1000 1000 1000 0.1 0.1 0.1 00 1500 Carbon monoxide 1500 1500 Carbon monoxide 900 900 900 700 700 700 500 500 500 300 300 300 100 100 100 00 150 150 150 Carbon Carbon Carbon 300 600 900 monoxide 300 monoxide 300 600 600 900 900monoxide 300 450 600 750 900 300 450 750 900 (g/l) 600 300Density 450 600 750 900 Density (g/l) Density (g/l) Carbon monoxide Carbon Carbonmonoxide monoxide Carbon monoxide 150 150 150 11 10 100 1010 100 Pressure (bar) 100 Pressure (bar) Pressure (bar) 100 K 100 KK K 100 150 150 KK K 150 200 200 KK K 200 300 300 300 400 KK K 400 KK K 400 500 500 KK 500 1000 1000 1000 Viscosity ( mPa.s) Viscosity mPa.s) Viscosity (( mPa.s) Viscosity ( mPa.s) Sound Spd (m/s) Sound Spd (m/s) Sound Spd (m/s) Sound Spd (m/s) 0.1 0.10.1 0.01 0.01 0.01 10 1010 100 100 100 Pressure (bar) Pressure (bar) Pressure (bar) 100 K 100 KK K 100 300 300 KK K 300 500 500 KK 500 200 K 200 KK K 200 400 400 KK K 400 150 150 KK 150 1000 1000 1000 Figure Predicted and experimental (NIST Chemistry Web Book) isobaric heat capacity, liquid density, viscosity and speed of sound of carbon monoxide PETROVIETNAM - JOURNAL VOL 6/2020 49 PETROLEUM PROCESSING cases, the average absolute deviation obtained on vapour N liq N sat sat li q li q pressure, liquid density is within Psaturated Pesxapt viscosities Pand cal cal ex p Fobj li q the experimental N accuracy (lower Pesxaptthan 2%) N [2] sat l iq 1 ex p P The deviation is defined as: AAD(%) exp 100 data cal (7) exp Results and discussion The liquid density, isobaric heat capacity, speed of sound and viscosity of seven gases were predicted in the temperature range of 100K to 600K and pressure up to 2,000 bars This extrapolation test seems to be more Carbondioxide dioxide Carbon Carbon Carbondioxide dioxide 230KK 230 230 230KK 260KK 260 260 260KK 330KK 330 330 330KK 370KK 370 370 370KK 420KK 420 420 420KK 500KK 500 500 500KK 600KK 600 600 600KK 300 300 300 300 90 90 90 90 1,810 1,810 1,810 1,810 30 30 30 30 1,240 1,240 1,240 1,240 60 60 60 60 30 30 30 30 670 670 670 670 11 11 10 100 10 100 10 100 10 100 Pressure(bar) (bar) Pressure Pressure Pressure(bar) (bar) 150 150 150 150 33 33 00 00 1000 1000 1000 1000 100 100 100 100 500 500 500 500 800 1,100 1,100 1,400 1,400 800 800 800 1,100 1,100 1,400 1,400 400 800 400 800 400 800 400 Density 800 Density(g/l) (g/l) Density (g/l) Density (g/l) 11 11 10 10 10 10 100 100 100 100 Pressure(bar) (bar) Pressure Pressure Pressure(bar) (bar) 230KK 230 230 230KKKK 260 260 260 260KKKK 330 330 330 330KKKK 370 370 370 370KKKK 420 420 420 420KKKK 500 500 500 500KKKK 600 600 600 600KK 1000 1000 1000 1000 Viscosity mPa.s) Viscosity (( mPa.s) Viscosity mPa.s) Viscosity (( mPa.s) 0.12 0.12 0.12 0.12 0.012 0.012 0.012 0.012 11 11 10 10 10 10 100 100 100 100 Pressure(bar) (bar) Pressure Pressure Pressure(bar) (bar) Figure Predicted and experimental (NIST Chemistry Web Book) isobaric heat capacity, liquid density, viscosity and speed of sound of carbon dioxide 50 1,200 1,200 1,200 1,200 Carbondioxide dioxide Carbon Carbon Carbondioxide dioxide Carbondioxide dioxide Carbon Carbon Carbondioxide dioxide Sound Spd (m/s) Sound Spd (m/s) Sound Spd (m/s) Sound Spd (m/s) 1500 1500 1500 1500 230 230 230 230 KK KK 120 120 120 120 3000 3000 3000 3000 Carbon Carbondioxide dioxide Carbon Carbondioxide dioxide 260 260 260 260 KK KK Cp (J/mol*K) Cp (J/mol*K) Cp (J/mol*K) Cp (J/mol*K) 150 150 150 150 Figures to show the comparison between the predicted values obtained with the current model and the experimental data of several petroleum gases in both suband super critical regions The experimental data are taken from the NIST chemistry web book (http://webbook.nist gov/chemistry/fluid) An excellent match between the predicted and experimental liquid density and viscosity was obtained for all considered gases Considering the results of these figures, it is evident that the PC-SAFT+FVT model provides a very good result for heat capacity The Pressure (bar) Pressure (bar) Pressure (bar) Pressure (bar) 180 180 180 180 stringent than their correlation accuracy This prediction also allows to validate the prediction potential of the model over a wide range of thermodynamic conditions PETROVIETNAM - JOURNAL VOL 6/2020 230KK 260KK 230 260 230 260 230KK 260KK 310KK 330KK 310 330 310 K 330 310 K 330KK 370KK 420KK 370 420 370 420 370KK 420KK 500KK 600KK 500 600 500 600 500KK 600KK 1000 1000 1000 1000 PETROVIETNAM 1000 1000 1000 1000 7575 75 Oxygen Oxygen 75 Oxygen Oxygen 100100 K K 100 100KK Cp Cp (J/mol*K) (J/mol*K) Cp Cp(J/mol*K) (J/mol*K) 100 100 100 100 5050 50 50 100100 K K 100 K 100 KK K 300300 300 K 300 KK K 500500 500 K 500 K Pressure (bar) Pressure (bar) Pressure Pressure(bar) (bar) 1010 10 10 200200 K K 200 K 200 KK K 400400 400 K 400 KK K 600600 600 K 600 K 700 700 700 700 1 1 0.10.1 0.1 0.1 400 400 400 400 0.01 0.01 0.01 0.01 2525 25 25 1 1 1000 1000 1000 1000 Oxygen Oxygen Oxygen Oxygen Oxygen Oxygen Oxygen Oxygen 120120 120 120 1 1 1010 100100 10 100 10 Pressure (bar) Pressure (bar)100 Pressure (bar) Pressure (bar) 100100 K K 100 K 200200 100 KK K 200 K 200 KK K 300300 300 K 300 KK K 400400 400 K 500500 400 KK K 500 K 500 KK K 600600 600 K 600 K 1000 1000 1000 1000 Viscosity ( mPa.s) Viscosity ( mPa.s) Viscosity Viscosity( mPa.s) ( mPa.s) 0.10.1 0.1 0.1 Sound Spd.Spd (m/s) Sound (m/s) Sound SoundSpd Spd.(m/s) (m/s) 1200 1200 1200 1200 1010 100100 10 100 10 Pressure (bar) Pressure (bar)100 Pressure (bar) Pressure (bar) 100 Oxygen 100 Oxygen 100100 100 400 400 700 7001,000 1,0001,300 1,300Oxygen 0.001 0.001 100 100 400 700 1,000 1,300Oxygen 0.001 100 400 700 1,000 1,300 400 800 1,200 0.001 0 400 800 1,200 400Density 800 1,200 (g/l) Density (g/l) 400 Density 800 1,200 (g/l) Density (g/l) 100100 K K 200200 K K 100 K 200 K 100 KK 200 KK 300300 400 K 400 K 300 K 400 K 300 KK 400 KK 500500 K 600600 K 500 K 600 K 500 K 600 K 0.01 0.01 0.01 0.01 1 1 1010 100100 10 100 10 Pressure (bar) Pressure (bar)100 Pressure (bar) Pressure (bar) 1000 1000 1000 1000 Figure Predicted and experimental (NIST Chemistry Web Book) isobaric heat capacity, liquid density, viscosity and speed of sound of oxygen average absolute deviation results from experimental data is around - 3% for most of cases, except for iso-butane, at temperature lower than 200K, the predicted values deviate largely from the measured data In fact, the speed of sound is generally represented as a severe consistency test for any EoS, since it involves the temperature and density partial derivatives of pressure, and PC-SAFT is not able to describe with great accuracy the p(ρ, T) [4 - 6] The model was also not able to reproduce the transaction regions, e.g for iso-butane, the model could not match the 350K isotherm data ranging from bar to 10 bars, for both speed of sound and viscosity [11] Conclusion In this work, the PC-SAFT+FVT model has been applied to some petroleum and refinery gases The pure component parameters for several gases have been reported Single phase liquid density, isobaric heat capacity, sound velocity and viscosity of these molecules have been predicted and compared with experimental data Results have indicated that with the exception of the speed of sound at condition lower than 200K, PC-SAFT+FVT accurately predicts the thermodynamic properties of petroleum and refinery gases PC-SAFT is not adequate for predicting the isobaric heat capacity PETROVIETNAM - JOURNAL VOL 6/2020 51 PETROLEUM PROCESSING 1000 1000 1000 1000 1010 1010 11 Pressure(bar) (bar) Pressure Pressure(bar) (bar) Pressure Cp(J/mol*K) (J/mol*K) Cp Cp(J/mol*K) (J/mol*K) Cp 220 220 220 220 180 180 180 180 Iso Iso -butane Iso-butane -butane Iso -butane 100 100 100 100 400 400 400 400 0.1 0.1 0.1 0.1 350 350 350 350 0.01 0.01 0.01 0.01 300 300 300 300 0.001 0.001 0.001 0.001 250 250 250 250 0.0001 0.0001 0.0001 0.0001 140 140 140 140 200 200 200 200 0.00001 0.00001 0.00001 0.00001 150 150 150 150 0.000001 0.000001 0.000001 0.000001 100 100 100 100 11 1010 100 100 100 1010 100 Pressure Pressure (bar) (bar) Pressure(bar) (bar) Pressure 1000 1000 1000 1000 0.0000001 0.0000001 0.0000001 0.0000001 150K K 150 150KK 150 150 150 K KK 150 150 K 250 250 KK 250 250 K K 350 350 K KK 350 350 K 450 450 KK 450 450 K K 550 550 K KK 550 550 K Iso -butane 250K K 250 250KK 250 260 260 260 260 Iso Iso -butane Iso-butane -butane 100 100 100 100 200 200 200 200 500 500 800 800 500 800 500 800 300 300 600 600 300Density 600 300 600 Density (g/l) (g/l) Density (g/l) Density (g/l) 00 44 Iso Iso -butane Iso-butane -butane Iso Iso -butane Iso-butane -butane Iso -butane Iso -butane 1500 1500 1500 1500 Viscosity( mPa.s) ( mPa.s) Viscosity Viscosity( (mPa.s) mPa.s) Viscosity 150 150 K KK 150 150 K 250 250 K KK 250 250 K 350 350 K KK 350 350 K 450 450 K KK 450 450 K 550 550 K KK 550 550 K SoundSpd Spd.(m/s) (m/s) Sound SoundSpd Spd.(m/s) (m/s) Sound 0.4 0.4 0.4 0.4 150 150 150 150 150 150 K KK 150 150 K 250 250 KK 250 250 K K 350 350 K KK 350 350 K 450 450 KK 450 450 K K 550 550 K KK 550 550 K 11 1010 1010 100 100 100 100 Pressure Pressure (bar) (bar) Pressure (bar) Pressure (bar) 1000 1000 1000 1000 0.04 0.04 0.04 0.04 0.004 0.004 0.004 0.004 11 1010 1010 Pressure Pressure (bar) (bar) Pressure (bar) Pressure (bar) 100 100 100 100 Figure Predicted and experimental (NIST Chemistry Web Book) isobaric heat capacity, liquid density, viscosity and speed of sound of iso-butane of iso-butane at temperature lower than 450K These deviations were already observed in the prediction of other similar pure fluids such as alkanes or non-polar molecules [6, 12] For conclusion, the PC-SAFT+FVT model could be used as a robust estimator for the thermodynamic properties of petroleum gases with good accuracy, particularly in the temperature and pressure conditions of interest in the oil and gas industry The model is simple to incorporate into the design and simulation package such as Aspen Plus or Prosim, with the average absolute deviation obtained by the model being within the experimental incertitude 52 PETROVIETNAM - 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Six petroleum and refinery gases and oxygen have been studied These gases have been selected to test the model due to the availability of experimental data The regression of PC-SAFT+FVT model. .. properties of petroleum gases with good accuracy, particularly in the temperature and pressure conditions of interest in the oil and gas industry The model is simple to incorporate into the design and. .. The liquid density, isobaric heat capacity, speed of sound and viscosity of seven gases were predicted in the temperature range of 100K to 600K and pressure up to 2,000 bars This extrapolation