Hydrate and Phase Behavior Modeling in CO2-Rich Pipelines

Article pubs.acs.org/jced

Hydrate and Phase Behavior Modeling in CO2‑Rich Pipelines Antonin Chapoy, Rod Burgass, Bahman Tohidi,* and Ibrahim Alsiyabi Hydrates, Flow Assurance & Phase Equilibria Research Group, Institute of Petroleum Engineering, Heriot-Watt University, Edinburgh EH14 4AS, Scotland, U.K. ABSTRACT: Carbon dioxide transport will be a key part of any Carbon Capture and Storage (CCS) system. Generally for CCS, flow assurance modeling of these pipelines has been restricted to pure CO2 systems; however CO2 streams coming from capture processes are not pure and contain various components. These fluids have a certain level of moisture, so dehydration is needed before delivering CO2 rich fluid to the export pipeline, in order to prevent potential hydrate formation, two-phase flow and corrosion in the export line. In this contribution, the hydrate phase equilibria of the binary CO2 + (N2 or CH4 or O2 or Ar or CO) systems in the presence of a free water phase were determined as well as direct hydrate dissociation conditions of liquid CO2 in absence of a free phase. A rigorous and generalized model is presented to predict the phase behavior, hydrate dissociation pressures and the dehydration requirements of CO2 rich gases. A statistical thermodynamic approach, with the Cubic-Plus-Association equation of state, is employed to model the phase equilibria. The hydrate-forming conditions are modeled by the solid solution theory of van der Waals and Platteeuw. Predictions of the developed model are first validated using simple systems and then for more complicated synthetic multicomponent systems. Showing that accurate phase behavior prediction of CO2 rich stream is critical for accurate predictions of the hydrate phase behavior of these fluids. unexpected problems, for example, two-phase flow when only one phase was expected, higher dehydration requirements to avoid hydrate/ice problems, etc.2 In this work, experimental measurements of the locus of incipient hydrate-liquid water-vapor curve for binary CO2 + (N2 or CH4 or O2 or Ar or CO) systems in equilibrium with liquid water are presented at pressures up to 55 MPa. Direct hydrate dissociation measurements of a liquid CO2 system in the absence of any water phase (low water content system) were also performed to further test the model and validate our previous results.3,4 The Cubic-Plus-Association (CPA-EoS) or the Soave− Redlich−Kwong (SRK) (when no water is present) equation of state combined with the solid solution theory of van der Waals and Platteeuw (1959)5 as developed by Parrish and Prausnitz (1972)6 was employed to model the fluid and hydrate phase equilibria as previously described by Chapoy et al.3,4,7,8 The predictions of the thermodynamic model were compared with experimentally measured properties (saturation pressure, dew point, hydrates).

1. INTRODUCTION As nearly 40 percent of untapped hydrocarbon fields contain high concentrations of CO2 and H2S1 there is a requirement for accurate predictions of thermophysical properties essential for sound design of production facilities for such hydrocarbon systems. For example, in South East-Asia, the CO2 content is higher than 0.7 mole fraction in some gas fields. Such compositions can lead to many technical challenges and flow assurance issues, as well as a significant increase in processing costs. The CO2-rich stream captured from flue gases are also faced with similar challenges although likely to contain much higher CO2 concentration, different components (contaminants/impurities), and varying compositions of these contaminants. The presence of high concentrations of CO2 means that higher strength/specification transport pipelines are required in order to reduce the risk of ductile fracture. The presence of water may result in ice and/or gas hydrate formation, leading to pipeline restriction and blockage. Where a gas is compressed for transportation purposes it is necessary to know the effect of CO2 concentration in the stream on the physical properties of the fluid, that is, the system’s dew and bubble point pressure. This will allow accurate assessment of the compression requirement. A preliminary study showed that there was limited or no experimental data on the above systems. Therefore, using conventional thermodynamic models can lead to inaccurate estimation of fluid properties (e.g., dew point), or other © XXXX American Chemical Society

Special Issue: In Honor of E. Dendy Sloan on the Occasion of His 70th Birthday Received: September 10, 2014 Accepted: October 21, 2014

A

dx.doi.org/10.1021/je500834t | J. Chem. Eng. Data XXXX, XXX, XXX−XXX

Journal of Chemical & Engineering Data

Article

2. EXPERIMENTAL SECTION The majority of the setups and procedures used in this paper were described in detail in refs 3,4,7, and 8 A brief description of each setup is given below. 2.1. Materials. The ource and purity of gases used in this study are listed in Table 1. Deionized water was used in all hydrate tests. The binary mixtures compositions are listed in Table 2. The mixtures were prepared gravimetrically (uncertainty ± 0.3 mol %).

vessel with mixing ball, mounted on a horizontal pivot with associated stand for pneumatic controlled rocking mechanism (Figure 1). Rocking of the cell through 180 deg at a constant rate and the subsequent movement of the mixing ball within it, ensured adequate mixing of the cell fluids. Cell volume, hence pressure, can be adjusted by injecting/withdrawal of liquid behind the moving piston. The rig has a working temperature range of 203.15 K to 453.15 K, with a maximum operating pressure of 70 MPa. The system temperature is controlled by circulating coolant from a cryostat within a jacket surrounding the cell. The equilibrium cell and pipework were thoroughly insulated to ensure constant temperature. The temperature was measured and monitored by means of a PRT (platinum resistance thermometers) located within the cooling jacket of the cell (u(T) = ± 0.1 K). A Quartzdyne pressure transducer with an accuracy of ± 0.03 MPa was used to monitor the pressure. The weight of the fluids (i.e., water and the multicomponent CO2 fluid) injected are recorded prior to any measurements and the overall feed composition can thus be calculated. The calculated uncertainty on the overall aqueous mole fraction is ± 0.002. 2.3. Water Content Measurements and Procedures. The core of the equipment for water content measurement has been originally described by Chapoy et al. (2012).3 The setup comprises an equilibrium cell and a device for measuring the water content of equilibrated fluids passed from the cell. The equilibrium cell is similar to the one described in the saturation pressure measurements. The moisture/water content measurement setup consists of a heated line, a tunable diode laser adsorption spectroscope (TDLAS) from Yokogawa, and a flow meter. The estimated experimental accuracy of the water content is ± 5 ppm mole.

Table 1. Purity and Source of Samples Used in This Study chemical name

source

minimum mole fraction purity

argon carbon dioxide carbon monoxide methane nitrogen oxygen

BOC BOC BOC BOC BOC BOC

0.99999 0.99995 0.99900 0.99995 0.99998 0.99600

Table 2. Composition, mole, of the Synthetic Binary Mixtures Used in This Study impurity

CO2

mole (u = 0.003)

nitrogen methane carbon monoxide oxygen argon

balance

0.046 0.059 0.059 0.053 0.050

2.2. Hydrate Dissociation Measurements. Dissociation point measurements were conducted using a reliable isochoric step-heating method. Figure 1 shows the apparatus used to determine the phase equilibrium conditions. The equilibrium setup consisted of a piston-type variable volume (maximum effective volume of 300 mL), titanium cylindrical pressure

3. THERMODYNAMIC MODELING A general phase equilibrium model based on the uniformity of component fugacities in all phases is used to predict phase equilibria, water activity, and the hydrate forming conditions. A description of the thermodynamic model and parameters (in particular binary interaction parameters between components) can be found elsewhere.3,4,7,8 4. RESULTS AND DISCUSSION 4.1. Hydrate Dissociation in the Presence of Free Water. Carbon dioxide is known to form structure I gas hydrates under the appropriate temperature and pressure conditions. As carbon dioxide is subcritical at hydrate forming conditions and has a relatively low vapor pressure, different phases can be found in the hydrate−carbon dioxide−water system: a hydrate phase, a water rich liquid phase, an ice phase, a carbon dioxide-rich vapor phase and a carbon dioxide-rich liquid phase as well as two quadruple points. Experimental data for carbon dioxide hydrates have been measured and reported by various authors in the different hydrate regions. The thermodynamic model was compared to the stability zone of pure CO2 hydrate in the presence of a free-water phase. As seen in Figure 2, the experimental (collected from the open literature) and predicted phase boundaries for carbon dioxide hydrates are in good agreement. The predicted hydrate curve has a maximum temperature (about 294 K) as experimentally observed by Nakano et al. (1998),18 meaning that no CO2 hydrates can form above this temperature, no matter how high the pressure is.

Figure 1. Schematic illustration of equilibrium rig used for saturation pressure measurements. B



Article

Table 4. Experimental Hydrate Dissociation Conditions in the Presence of Deionized Water for the 0.941 mol CO2 + 0.059 mol CH4 System (AqFr: Aqueous Mole Fraction in the System) AqFr

1.82 2.68 3.61 5.81 12.25 19.97 12.25

0.96 0.94 0.92 0.57 0.54 0.53 0.54

Uncertainty on the aqueous mole fraction u(AqFr) = ± 0.002. Uncertainty on temperature u(T) = ± 0.1 K. cUncertainty on pressure u(P) = ± 0.05 MPa.

b

Table 5. Experimental Hydrate Dissociation Conditions in the Presence of Deionized Water for the 0.954 mol CO2 + 0.046 mol N2 System

Literature data are widely available for the carbon dioxide/ methane system. No experimental data were found in the open literature for CO2 with oxygen and argon. Data are available but limited for CO2 with nitrogen and carbon monoxide. Table 3 Table 3. Literature Data for Hydrate Equilibria of CO2 Binary Systems system

temp range

CO2/mole fraction

ref

a

CO2/CH4

264.1 to 275.5 275.5 to 85.7 273.7 to 287.6 280.3 273.5 to 283.1 273.56 to 285.56 272.66 to 285.76 273.5 to 283.2 275.9 to 277.7 273.1 to 280.2 273.4 to 284.25 272.85 to 284.25 274.15 to 283.2

∼0.5 0.274 to 0.824 0.08 to 0.85 0 to 1 0.13 to 0.53 0 to 1 0 to 1 0.95 to 0.9658 0.06 to 0.25 0.91 to 0.97 0 to 1 0.07 to 0.97 0.1

14 15 16 17 18 19 20 21 22 14 23 24 25

b

CO2/CO

P/MPa

a

Figure 2. Pressure vs temperature diagram for carbon dioxide + water. Black curves, model predictions (hydrate stability zone); dotted lines, model predictions (bubble lines); ●, data from Deaton and Frost (1946);9 ◆, data from Larson (1955);10 △, data from Takeuchi and Kennedi (1964);11 ○, data from Ng and Robinson (1985);12 ▲, data from Nakano et al. (1998);13 ∗, data from Chapoy et al. (2009).2

CO2/N2

T/K 276.00 279.20 281.35 284.15 285.75 286.95 285.75

T/K

P/MPa

AqFr

276.91 279.65 281.23 283.64 287.40 288.55

2.05 2.82 3.66 5.72 40.82 55.11

0.96 0.94 0.92 0.86 0.51 0.50


Table 6. Experimental Hydrate Dissociation Conditions in the Presence of Deionized Water for the 0.941 mol CO2 + 0.059 mol CO System T/K

P/MPa

AqFr

273.15 278.35 280.75 283.85 284.75 285.85

1.38 2.63 3.64 6.69 11.63 21.30

0.97 0.94 0.92 0.83 0.55 0.53


a

gives a list of these data, reporting temperature range and source of the experimental data. The experimental hydrate dissociations for the binary CO2+CH4, CO2+N2, CO2+CO, CO2+O2, and CO2+Ar in equilibrium with water are reported in Tables 4 to 8, respectively. The experimental hydrate dissociations for the binary CO2+CH4 and CO2+CO systems are also plotted in Figures 3 and 4 along with the predictions of the model. For predictions, only one intermediate aqueous fraction was used (AqFr = 0.8) as for these systems over the investigated aqueous fractions and pressure, the effect is relatively negligible. Overall experimental data are well predicted by the thermodynamic model and most points are within the estimated experimental accuracy. The model can be further tested by predicting the hydrate conditions of a multicomponent fluid in equilibrium with water reported by Chapoy et al.7 The data are plotted in Figure 5 along with the prediction of the dry multicomponent mixture phase envelope, the pure CO2 hydrate stability zone, CH4 hydrate stability zone, and of a typical natural gas (CH4 content, 0.8806 mol)26 hydrate stability zone for comparison. As seen for the CO2-rich systems, we have first a vapor +

b

Table 7. Experimental Hydrate Dissociation Conditions in the Presence of Deionized Water for the 0.947 mol CO2 + 0.053 mol O2 System T/K

P/MPa

AqFr

276.75 278.85 281.75 284.01 285.25 285.75

2.05 2.68 4.05 7.04 13.19 18.33

0.96 0.94 0.91 0.56 0.54 0.53


a b

hydrate + liquid water line, then a vapor + liquid-rich CO2 + hydrate + liquid water line and finally a liquid-rich CO2 + C



Article

Table 8. Experimental Hydrate Dissociation Conditions in the Presence of Deionized Water for the 0.95 mol CO2 + 0.50 mol Ar System T/K

P/MPa

AqFr

275.45 280.55 284.05 285.25 285.65

1.72 3.22 5.81 11.26 16.07

0.97 0.93 0.85 0.55 0.53


a b

Figure 5. Predicted and experimental7 hydrate stability of pure CO2, pure CH4, a CO2-rich stream, and a natural gas in the presence of distilled water: ●, CO2-rich stream hydrate stability zone;7 ○, dry system saturation points;7 ●, natural gas hydrate stability zone;26 ◇, pure CO2 hydrate stability zone;2 black lines; hydrate stability zone predicted using the CPA-EoS model using an aqueous mole fraction of 0.8; dotted lines, phase envelope of the dry system (no water) using the SRK-EoS; broken lines, pure CO2 hydrate stability zone predicted using the CPA-EoS model.

and the CO2-rich multicomponent mixture like methane are forming structure I hydrate. Pure CO2 and the CO2-rich multicomponent are more stable than methane hydrate up to about 7 MPa and are far less stable in the liquid-rich CO2 region. When compared to a typical natural gas forming structure II at the same aqueous fraction, these CO2 systems are less thermodynamically stable over the full pressure range (i.e., in excess of 10 K at 15 MPa), which is a positive. 4.2. Hydrate Dissociation in the Absence of a FreeWater Phase. The water content in the CO2-rich phase in equilibrium with liquid water predicted by the model has also been compared to literature data from 298.15 K (Figure 6), 423.15 K (Figure 7), and 478.15 K (Figure 7) and pressure to 150 MPa. As seen in Figure 6 (below the critical point of pure CO2), different phases can be found in the carbon dioxide− water system at this temperature: a water-rich liquid phase, a carbon dioxide-rich vapor phase, and a carbon dioxide-rich liquid phase. At the VLL point, two water content values can be found, one in the vapor phase and one in the liquid CO2-rich phase, hence the sharp discontinuity in water content at this (or any other) subcritical temperatures. Below the VLL locus, the water content is decreasing with pressure. Above the VLL locus in the liquid CO2 phase, pressure has a limited influence (in the pressure range investigated) on the water content. Above the critical point of pure CO2 as seen in Figure 7, the model can predict accurately the distribution of water in the CO2-rich phase and the water content trend with pressure is smoother Data at low temperatures are far more limited. Experimental data on water contents for CO2 in equilibrium with hydrates from 223.15 K to 263.15 K up to 10 MPa have been measured by Burgass et al.4 Chapoy et al.7 have reported water content at 15 MPa from 233.15 Kto 288.15 K. The results from Burgass et al.4 are plotted in Figure 8 along with predicted values. As can be seen there is good agreement between experimental results and predicted values. The same step change in the water contents for CO2 in equilibrium with hydrates than for CO2 in

Figure 3. Predicted and experimental hydrate stability of the CO2− CH4 binary system in the presence of distilled water: ◇, this work; black lines, hydrate stability zone predicted using the CPA-EoS model using an aqueous mole fraction of 0.8; dotted lines, phase envelope of the dry system (no water) using the SRK-EoS.

Figure 4. Predicted and experimental hydrate stability of the CO2− CO binary system in the presence of distilled water: ◇, this work; black lines, hydrate stability zone predicted using the CPA-EoS model using an aqueous mole fraction of 0.8; dotted lines, phase envelope of the dry system (no water) using the SRK-EoS.

hydrate + liquid water line. The bubble point of all these mixtures are higher than that of pure CO2, hence hydrates would be more stable in the liquid-rich CO2 region, as the vapor + liquid rich CO2 + hydrate + liquid water line is intersecting the bubble line at a higher temperature. Pure CO2 D



Article

Figure 6. Pxy, phase equilibria in the carbon dioxide + water system at 298.15 K. Black Lines, model predictions. Experimental data from ◆, Wiebe and Gaddy (1941);27 △, Gillepsie and Wilson (1982);28 ▲, Nakayama et al. (1987);29 ∗, King et al. (1992);30 ○, Hou et al. (2013);31 ◇, Valtz et al. (2004).33

Figure 8. Water content in the vapor and liquid phases of carbon dioxide in equilibrium with hydrates or liquid water at (223.15, 233.15, 243.15, 253.15, 263.15, 288.15, and 298.15) K. Black lines, model predictions; ●, 263.15 K;7 ▲, 253.15 K;7 ○, 243.15 K;7 ◆, 233.15 K;7 ■, 223.15 K.7 Experimental data at 288.15 K from ∗, Gillepsie and Wilson (1982);28 △, King et al. (1992);30 ◇, Valtz et al. (2004).33 □, Jarne et al. (2004).34 Experimental data at 298.15 K from, gray triangle, Hou et al. (2013);31 gray circle, King et al. (1992).30

Figure 7. Water Content in carbon dioxide in equilibrium with liquid water at 423.15 K and 478.35 K. Black lines, model predictions. Experimental data from ◆, Takenouchi and Kennedy (1964);11 ∗, Gillepsie and Wilson (1982);28 ◇, Tabasinejad et al. (2011)32 at 422.98 K and 478.35 K; ●, Hou et al. (2013).31

equilibrium with liquid water is observed when there is a transition from vapor to liquid. In a previous work by Youssef et al. (2009),35 the measurement of hydrate formation and dissociation temperature of CO2 hydrates, in the absence of any aqueous phase, by measurement of the water content in the vapor phase was demonstrated. It was decided to conduct a similar test but with liquid CO2 in the absence of any aqueous phase. Initially a small amount of water, 0.15 mL, was injected into the cell. The temperature was then reduced to 263.15 K, and the cell was vacuumed prior to injecting high purity CO2. The pressure in the cell was maintained constant at 8.89 MPa by adjusting the cell volume as required. The test was started at a temperature of 288.15 K, therefore significantly higher than the expected hydrate formation temperature. The temperature was then reduced stepwise, measuring the water content of the equilibrium liquid CO2. Once the temperature was below the predicted hydrate formation temperature at the set pressure the temperature was reduced to 249.15 K in order to give sufficient

subcooling to form hydrates. The temperature was then increased stepwise again measuring the water content at each temperature once equilibrated. The water content measurements at each temperature are plotted in Figure 9. As can be seen from Figure 9, the measured water contents for the step-cooled temperatures between 273.15 and 268.25 are close to 1100 ppm mole water (0.0011 mol). On cooling to 249.15 K the water content reduces significantly indicating hydrate formation. On stepheating the water content increases at each temperature as would be expected for liquid CO2 in equilibrium with hydrates until all the water is dissolved in the CO2 liquid phase and the water content remains constant with increasing temperature. The results show that this method can be used to indicate hydrate formation and dissociation using water content measurements. The results from this test with liquid CO2 combined with those reported by Youssef et al. (2009)35 with E



Article

agreement with some deviation (AAD ≈ 5 %). As expected, for this multicomponent system, less water can be dissolved than in pure CO2, because the amount of water that can be dissolved in small molecules such as N2, O2, etc. is lower at the same temperature and pressure than in liquid CO2. As seen in this figure, the water contents for the multicomponent system are between the water contents of pure CO2 and pure CH4; however, there is no direct relation between the CO 2 composition in these fluids and the reductions observed compared to the water content in pure CO2.

5. CONCLUSIONS Knowledge of the phase behavior of CO2-rich systems is currently of great importance for both the energy industry and ultimately the environment. As discussed in this work, very limited reliable experimental data are available in the literature on the vapor/liquid−liquid equilibria for the CO2−water system. Very few data sets are available for CO2-hydrate formation under saturated conditions. It is, therefore, planned to extend this work to a wider range of temperatures to further validate/improve the developed thermodynamic model. In this communication the phase behavior and some properties of a CO2-rich stream have been studied, such as the phase envelope, the hydrate stability, and dehydration requirement of the mixture. Models have been developed to calculate and predict these properties. The main impacts of the high CO2 concentration are summarized as follows: (i) The single liquid phase region of the CO2-rich mixture is 2 MPa to 5 MPa higher than for pure CO2 in the studied temperature range. (ii) More water can be dissolved in the stream compared to pure CH4; hence, the dehydration requirement for this type of fluid could be more stringent. (iii) The developed models are in good agreement with the measured experimental data. Future work will concentrate on the determination and modeling of properties for other types of CO2-rich streams (different CO2 concentrations, impact of H2S, etc.).

Figure 9. Plot showing the determination from plot of change in water content measurements versus temperature for CO2 at 8.89 MPa at different temperatures on step-heating and step-cooling. △, Stepheating point; ●, step-cooling points; gray diamond, determined hydrate dissociation point for CO2 with 1100 ppmmole water at 8.89 MPa. The equilibrium dissociation point is determined as being the intersection between the two water content traces (inside the hydrate stability zone, the water content increases nearly exponentially with temperature as a result of the change in the water vapor pressure of hydrate; outside the hydrate stability zone, all the water is now dissolved in the liquid CO2 phase, an increase in the temperature would not change the water content).

vapor CO2 demonstrate that it is possible to identify hydrate formation/dissociation using water content measurements. It is also worth noting that the model accurately predicts the hydrate dissociation of the CO2 + 1100 ppm water mixture (Figure 9). For multicomponent CO2-rich mixtures, the only available data are from Chapoy et al.7 They have reported water content at 15 MPa from 233.15 K to 288.15 K for a synthetic CO2-rich fluid (CO2, 0.8983 mol; O2, 0.0505 mol; Ar, 0.0205 mol; N2, 0.0307 mol). The experimental water content data in equilibrium with hydrates for pure CO2 and the multicomponent systems are plotted along with predictions of the thermodynamic model in Figure 10. As can be seen from the figure the experimental and predicted data are in good

■

AUTHOR INFORMATION

Corresponding Author

*Tel.: + 44 131 451 3672. E-mail: [email protected]. uk. Funding

This work is part of an ongoing Joint Industrial Project (JIP) conducted jointly at the Institute of Petroleum Engineering, Heriot-Watt University and the CTP research Center of MINES ParisTech. The JIP is supported by Chevron, GALP Energia, Linde AG, OMV, Petroleum Expert, Statoil, TOTAL and National Grid Carbon Ltd, which is gratefully acknowledged. Notes

The authors declare no competing financial interest.

■

Figure 10. Plot showing experimental water content data and predictions for the water content of pure CH4, pure CO2, and the CO2-rich stream (CO2, 0.8983 mol; O2, 0.0505 mol; Ar, 0.0205 mol; N2, 0.0307 mol) at 15 MPa and different temperatures: ◇, pure CO2;7 black lines, water content predictions using the CPA-EoS model for pure CO2; ●, multicomponent system;7 black dotted lines, predictions using the CPA-EoS model for the multicomponent system; broken lines, predictions using the CPA-EoS model for methane.

REFERENCES

(1) Lallemand, F.; Perdu, G.; Maretto, C.; Weiss, C. Magne-Drisch, J. Lucquin A.-C. Solutions for the treatment of highly sour gases, Digital Refining, April 2012. (2) Chapoy, A.; Burgass, R.; Tohidi, B. Effect of common impurities on the phase behaviour of carbon dioxide rich systems: Minimizing the

F



Article

risk of hydrate formation and two-phase flow. The SPE Offshore Europe Conference, Aberdeen, Scotland, 2009. (3) Chapoy, A.; Haghighi, H.; Burgass, R.; Tohidi, B. On the phase behaviour of the carbon dioxide−water systems at low temperatures: Experimental and modelling. J. Chem. Thermodyn. 2012, 47, 6−12. (4) Burgass, R.; Chapoy, A.; Duchet-Suchaux, P.; Tohidi, B. Experimental water content measurements of carbon dioxide in equilibrium with hydrates at (223.15 to 263.15) K and (1.0 to 10.0) MPa. J. Chem. Thermodyn. 2014, 69, 1−5. (5) Van der Waals, J. H.; Platteeuw, J. C. Clathrate solutions. Adv. Chem. Phys. 1959, 2, 2−57. (6) Parrish, W. R.; Prausnitz, J. M. Dissociation pressures of gas hydrate formed by gas mixture. Ind. Eng. Chem. Process. Des. Dev. 1972, 11, 26−34. (7) Chapoy, A.; Nazeri, M.; Kapateh, M.; Burgass, R.; Coquelet, C.; Tohidi, B. Effect of impurities on thermophysical properties and phase behaviour of a CO2-rich system in CCS. Int. J. Greenhouse Gas Control 2013, 19, 92−100. (8) Haghighi, H.; Chapoy, A.; Tohidi, B. Freezing point depression of electrolyte solutions: Experimental measurements and modeling using the cubic-plus-association equation of state. Ind. Eng. Chem. Res. 2008, 47, 3983−3989. (9) Deaton, W. M.; Frost, E. M. J. Gas hydrate composition and equilibrium data. Oil Gas J. 1946, 45, 170−178. (10) Ng, H. J.; Robinson, D. B. Hydrate formation in system containing methane, ethane, propane, carbon dioxide or hydrogen sulphide in the presence of methanol. Fluid Phase Equilib. 1985, 21, 144−155. (11) Takenouchi, S.; Kennedy, G. C. Dissociation pressures of the phase CO2-5.75H2O. Geological Notes No. 293; Institute of Geophysics, University of California: Berkeley, CA, 1964: pp 383−390. (12) Larson, S. D. Phase studies of the two-component carbon dioxide−water system, involving the carbon dioxide hydrate. Ph.D. Thesis, University of Illinois, Urbana-Champaign, 1955. (13) Nakano, S.; Moritoki, M.; Ohgaki, K. High-pressure phase equilibrium and raman microprobe spectroscopic studies on the CO2 hydrate system. J. Chem. Eng. Data 1998, 43, 807−810. (14) Fan, S. S.; Guo, T. M. Hydrate formation of CO2-rich binary and quaternary gas mixtures in aqueous sodium chloride solutions. J. Chem. Eng. Data 1999, 44, 829−832. (15) Unruh, C. H.; Katz, D. L. Gas hydrates of carbon dioxide− methane mixtures. J. Pet. Technol. Trans. 1949, 1, 83−86. (16) Adisasmito, S.; Frank, R. J.; Sloan, E.D. J. Hydrates of carbon dioxide and methane mixtures. J. Chem. Eng. Data 1991, 36, 68−71. (17) Ohgaki, K.; Takano, K.; Sangawa, H.; Matsubara, T.; Nakano, S. Methane exploitation by carbon dioxide from gas hydrates: Phase equilibria for CO2-CH4 mixed hydrate system. J. Chem. Eng. Jpn. 1996, 29, 478−483. (18) Servio, P.; Lagers, F.; Peters, C. J.; Englezos, P. Gas hydrate phase equilibrium in the system methane carbon dioxide neohexane and water. Fluid Phase Equilib. 1999, 158, 795−800. (19) Seo, Y.-T.; Lee, H.; Yoon, J.-H. Hydrate phase equilibria of the carbon dioxide, methane, and water system. J. Chem. Eng. Data 2001, 46, 381−384. (20) Seo, Y.-T.; Lee, H. Multiple-phase hydrate equilibria of the ternary carbon dioxide, methane, and water mixtures. J. Phys. Chem. B 2001, 105, 10084−10090. (21) Dholabhai, P. D.; Bishnoi, P. R. Hydrate equilibrium conditions in aqueous electrolyte solutions: mixtures of methane and carbon dioxide. J. Chem. Eng. Data 1994, 39, 191−194. (22) Elliot, D. G.; Chen, J. J. Process for separating selected components from multi-component natural gas streams. US Patent WO 97/09271, 1997. (23) Olsen, B.; Majumdar, A. J.; Bishnoi, P. R. Experimental studies on hydrate equilibrium carbon dioxide and its systems. Int. J. Soc. Mater. Eng. Resour. 1999, 7, 17−23. (24) Kang, S.-P.; Lee, H.; Lee, C.-S.; Sung, W.-M. Hydrate phase equilibria of the guest mixtures containing CO2, N2 and tetrahydrofuran. Fluid Phase Equilib. 2002, 185, 101−109.

(25) Mohammadi, A. H.; Anderson, R.; Tohidi, B. Carbon monoxide clathrate hydrates: Experimental equilibrium data and thermodynamic modeling. AIChE J. 2005, 51, 2825−2833. (26) Chapoy, A.; Tohidi, B.; Hydrates in High Inhibitor Concentration Systems. GPA Research Report 205, RR-205; Gas Processing Association: Tulsa, OK, 2011. (27) Wiebe, R.; Gaddy, V. L. Vapor phase composition of the carbon dioxide−water mixtures at various temperatures and at pressures to 700 atm. J. Am. .Chem. Soc. 1941, 63, 475−477. (28) Gillespie, P. C.; Wilson, G. M. Vapor−liquid and liquid−liquid equilibria: Water−methane, water−carbon dioxide, water−hydrogen sulfide, water−n-pentane, water−methane−n-pentane; Research report RR-48; Gas Processors Association: Tulsa, OK, 1982. (29) Nakayama, T.; Sagara, H.; Arai, K.; Saito, S. High pressure liquid−liquid equilibria for the system of water, ethanol, and 1,1difluoroethane at 323.2 K. Fluid Phase Equilib. 1987, 38, 109−127. (30) King, M. B.; Mubarak, A.; Kim, J. D.; Bott, T. R. The mutual solubilites of water with supercritical and liquid carbon dioxide. J. Supercrit. Fluids. 1992, 5, 296−302. (31) Hou, S.-X.; Maitland, G. C.; Trusler, J.P. M. Measurement and modeling of the phase behavior of the (carbon dioxide+ water) mixture at temperatures from 298.15 K to 448.15 K. J. Supercrit. Fluids. 2013, 73, 87−96. (32) Tabasinejad, F.; Moore, R. G.; Mehta, S. A.; Van Fraassen, K. C.; Barzin, Y.; Rushing, J. A.; Newsham, K. E. Water solubility in supercritical methane, nitrogen, and carbon dioxide: Measurement and modeling from 422 K to 483 K and pressures from 3.6 MPa to 134 MPa. Ind. Eng. Chem. Res. 2011, 50, 4029−4041. (33) Valtz, A.; Chapoy, A.; Coquelet, C.; Paricaud, P.; Richon, D. Vapourliquid equilibria in the carbon dioxide−water system, measurement, and modelling from 278.2 K to 318.2 K. Fluid Phase Equilib. 2004, 226, 333−344. (34) Jarne, C.; Blanco, S. T.; Artal, M.; Rauzy, E.; Oti, S.; Velasco, I. Dew points of binary carbon dioxide + water and ternary carbon dioxide + water + methanol mixtures: Measurement and modeling. Fluid Phase Equilib. 2004, 216, 85−93. (35) Youssef, Z.; Barreau, A.; Mougin; Jose, J.; Mokbel, I. Measurements of hydrate dissociation temperature of methane, ethane, and CO2 in the absence of any aqueous phase and prediction with the cubic plus association equation of state. Ind. Eng. Chem. Res. 2009, 48, 4045−4050.

G


Hydrate and Phase Behavior Modeling in CO2-Rich Pipelines

Recommend Documents