Joule-Thomson Inversion Curve Research Articles

Upper limit estimate to wellhead flowing pressure and applicable gas production for a downhole throttling technique in high-pressure–high-temperature gas wells

In recent years, China has explored and exploited several high-pressure deep gas fields. Normally, high-pressure gas wells are gathered and processed through multichoke manifolds on well sites, creating hazards such as high wellhead flowing pressure (Pt) and high risk for on-site operation personnel. Moreover, downhole chokes have been used in place of surface chokes. In doing this, the Joule–Thomson (JT) effect is geothermally regulated, alleviating the formation of hydrates in surface facilities. However, its applicability to high-pressure gas wells is less explored. In an effort to guide its use, the objective of this study is to set selection criteria in terms of the allowable wellhead Pt and gas flow rate. First, isenthalpic lines are separately estimated for dry gas and high liquid hydrocarbon (LHC) content gas condensate at various inlet temperatures with the use of commercial software. Next, by analysis of the resulting isenthalpic curves, several results are obtained on the JT inversion curves and throttling process through a choke. Third, building on these insights, a method for projecting the maximum Pt is presented, leading to a value of 52.5 MPa. Finally, multiparameter models are separately run for two deep gas wells (8100 m and 5000 m), reinforcing the result of the pressure upper limit while maintaining a maximum daily gas production of 14 E4 m3. Both upper limits with a maximum Pt of 52.5 MPa and daily gas production of 14 E4 m3 are corroborated with field data records. These findings are vital to the selection of a viable high-pressure gas well for applying the downhole throttling technique.

Thermodynamic evaluation of the effects of hydrogen blending on the Joule-Thomson characteristics of hydrogen-blended natural gas

The Joule-Thomson characteristics of hydrogen-blended natural gas (HBNG) differ from those of natural gas for the differences in properties, deserving a profound study. We foremost analyzed the effects of hydrogen on the properties of HBNG using the Soave-Benedict-Webb-Rubin (BWRS) equation of state (EOS) owing to its lowest deviation among the concerned EOSs. Based on BWRS EOS, the fundamental differential equation, and the isenthalpic equation, we developed a thermodynamic model to evaluate the effects of hydrogen on the isenthalpic curve, Joule-Thomson coefficient (JTC), and Joule-Thomson inversion curve (JTIC) of HBNG within the hydrogen mole fraction (x-H2) range of 30%. The average absolute relative deviation (AARD) for the isenthalpic curve of the N2-H2 mixture and the JTC of natural gas is 0.02% and 1.62%. We mainly discussed how hydrogen affects the isenthalpic curve, JTC, and JTIC of HBNG. The isenthalpic curve of the CH4-H2 mixture and HBNG rise in a descending gradient with increasing x-H2. Compared to natural gas, the JTC of HBNG decreases (about 48% when x-H2 is 30%) and negatively correlates to x-H2, pressure, and temperature in a nonlinear function. The JTC is more sensitive to the x-H2 at higher temperatures and lower pressures. The blended hydrogen narrows the positive effect region of HBNG but does not turn the positive effect into a negative one within the x-H2 range of 30%. When x-H2 increases from 0% to 30%, the maximum inversion pressure and corresponding temperature drop at a rate of 0.227 MPa/x-H2% (roughly linear) and 4.9385 K/x-H2% (linear), respectively.

The Joule–Thomson effect of (CO2 + H2) binary system relevant to gas switching reforming with carbon capture and storage (CCS)

The Joule–Thomson effect is one of the important thermodynamic properties in the system relevant to gas switching reforming with CCS. In this work, a set of apparatus was set up to determine the Joule–Thomson effect of binary mixtures (CO2 + H2). The accuracy of the apparatus was verified by comparing with the experimental data of carbon dioxide. The Joule–Thomson coefficients (μJT) for (CO2 + H2) binary mixtures with mole fractions of carbon dioxide (xCO2= 0.1, 0.26, 0.5, 0.86, 0.94) along six isotherms at various pressures were measured. Five equations of state EOSs (PR, SRK, PR, BWR and GERG-2008 equation) were used to calculate the μJT for both pure systems and binary systems, among which the GERG-2008 predicted best with a wide range of pressure and temperature. Moreover, the Joule–Thomson inversion curves (JTIC) were calculated with five equations of state. A comparison was made between experimental data and predicted data for the inversion curve of CO2. The investigated EOSs show a similar prediction of the low-temperature branch of the JTIC for both pure and binary systems, except for the BWRS equation of state. Among all the equations, SRK has the most similar result to GERG-2008 for predicting JTIC.

Calculation of Joule-Thomson and isentropic expansion coefficients for two-phase mixtures

Joule–Thomson (JT) and isentropic expansion coefficients describe the temperature change induced by a pressure variation under isenthalpic and isentropic conditions, respectively. They are commonly used to model a variety of processes in which either fluid compression or expansion is involved. While a lot of work has been devoted to inferring the JT coefficient from an equation of state when the fluid is a single phase, little attention has been paid to multiphase fluids, where phase equilibrium has to be taken into account; previous work has only addressed the construction on the JT inversion curve. In the present paper, we describe and implement an approach to calculate these two coefficients for multi-component fluid systems, including when they form two different phases, liquid, and vapor, in thermodynamic equilibrium. The only ingredients are an equation of state and expressions for the ideal part of the specific heats of the fluid components. We make use of cubic equations of state, but any thermodynamic model can be used in the proposed framework. Calculations conducted with typical geofluids, some of them containing CO2, show that these coefficients are discontinuous at phase boundaries (where enthalpy and entropy variations exhibit angular points), as expected with any thermodynamic quantity built from first-order derivatives of state functions, and cannot be simply inferred from the coefficients of the liquid and vapor phases.

Calculation of Virial Coefficients, Joule–Thomson Inversion Curve and Mutual Diffusion for Binary Mixtures

Calculation of Virial Coefficients, Joule–Thomson Inversion Curve and Mutual Diffusion for Binary Mixtures

Assessment of thermodynamic models via Joule–Thomson inversion

The performance of thermodynamic models is assessed with respect to Joule–Thomson inversion on the basis of 29 fluids with varying molecular structure. Three thermodynamic model types are considered: classical force fields, the molecular-based PC-SAFT equation of state (EOS) and empirical multi-parameter EOS. The force fields consist of Lennard–Jones and multi-polar interaction sites and were evaluated by molecular dynamics simulation and integration of Mayer’s f function. The force fields and PC-SAFT were parameterized solely to vapor-liquid equilibrium data, while basically all available experimental thermodynamic property data have been used in the development of the empirical EOS. The fluids considered in this comparison comprise noble gases, triangular polar molecules, linear quadrupolar molecules, hydrogen boding molecules, cyclic alkanes, aromatics and siloxanes. It is found that the physically motivated models (force fields and PC-SAFT) provide throughout realistic predictions for the Joule–Thomson inversion curve. Upon extrapolation, about half of the empirical EOS yield reasonable results, the remainder show deficiencies. The three model types are in good mutual agreement at low and moderate temperatures, deviations are observed at high temperatures. In most cases, PC-SAFT systematically predicts a higher ideal gas limit temperature of the Joule–Thomson inversion curve than the force fields. By expressing the characteristic points of the Joule–Thomson inversion curve in terms of the critical temperature and pressure, the adequacy of the classical corresponding states principle is discussed.

Thermodynamic analysis and process optimization of a natural gas liquid recovery unit based on the Joule – Thomson process

A thermodynamic analysis was conducted on the Joule-Thomson (JT) process to improve separation performance and exergy efficiency of a three-stage throttling process in a natural gas liquid (NGL) recovery plant. The JT inversion curve (JTIC) along with the phase envelope diagram (PED) were used to study phase transition during the throttling process. Three different objective functions—maximization of NGL recovery rate, improvement of cooling performance, and minimization of the exergy destruction—were investigated in this study to increase the NGL recovery rate with minimum energy consumption. It was observed that the improvement of cooling performance did not always increase the NGL recovery rate. Therefore, the cooling performance is not a suitable objective function for optimizing the JT process. To find the optimal operating condition seven different intermediate pressure ratios were defined. Then, the influence of the number of stages and intermediate pressure ratio on these objective functions was studied. The results showed that upon changing the pressure gradient from 35 to 5 bar, the exergy efficiency of JT valve 2 and JT valve 3 improved from 91.6 to 98.9% and 91–98.4%, respectively. In addition, when the pressure gradient in the JT valve 2 changed from 5 bar to 35 bar, the NGL recovery rate at this stage increased from 1.54 to 21.79 kmol/h. The results indicated that the optimum operational condition was obtained at the intermediate pressure ratio.

Prediction of Joule–Thomson coefficients and inversion curves of natural gas by various equations of state

The Joule-Thomson effect is an important thermodynamic phenomenon for natural gas-related industries. Hence, accurate prediction of the Joule–Thomson coefficient (JTC) and the Joule–Thomson inversion curve (JTIC) are of great importance in various industries. In this contribution, we apply six equations of state (EOSs) including SAFT, PρT-SAFT, SAFT-CP, PC-SAFT, and I-PC-SAFT, as well as SRK, to predict JTC and JTIC of eight main pure components of natural gas including methane, ethane, propane, n-butane, isobutane, pentane, carbon dioxide, and nitrogen. We also predict the JTC and JTIC for four and six synthetic mixtures of natural gas, respectively. By comparing the results of the six EOSs for prediction of natural gas-related pure and mixtures JTC and JTIC with literature data, we can conclude that although all the EOSs were in reasonable agreement with the literature data, in general, to predict the JTC and JTIC for all studies systems, SAFT-CP and original SAFT equations of state had the best results.

The full range Joule-Thomson inversion curve of helium-3

This paper reports the full range Joule-Thomson inversion curve of helium-3 ( 3 He) constructed by a virial-type equation of state of this quantum fluid. In order to evaluate the equation of state, the virial coefficients of 3 He calculated from the result of the analysis of this study are compared with previous studies. The inversion curve is confirmed to agree with the empirical inversion points reported previously. The peak temperature and the peak pressure of the inversion curve are respectively determined to be 19.6 K and 2.588 MPa. The minimum and the maximum inversion temperatures at zero pressure are estimated to be 2.8 K and 48.5 K, respectively. The reduced inversion curve of 3 He is also obtained with the critical parameters and it is compared with other reduced inversion curves of quantum and non-quantum fluids. The discrepancy of the reduced inversion curve of 3 He from the general reduced inversion curves is explained by means of the thermal de Broglie wavelength, similar to other quantum fluids.

Joule-Thomson Effect on a CCS-Relevant (CO2 + N2) System.

The Joule–Thomson effect is a key chemical thermodynamic property that is encountered in several industrial applications for CO2 capture and storage (CCS). An apparatus was designed and built for determining the Joule–Thomson effect. The accuracy of the device was verified by comparing the experimental data with the literature on nitrogen and carbon dioxide. New Joule–Thomson coefficient (μJT) measurements for three binary mixtures of (CO2 + N2) with molar compositions xN2 = (0.05, 0.10, 0.50) were performed in the temperature range between 298.15 and 423.15 K and at pressures up to 14 MPa. Three equations of state (GERG-2008 equation, AGA8-92DC, and the Peng–Robinson) were used to calculate the μJT compared with the corresponding experimental data. All of the equations studied here except PR have shown good prediction of μJT for (CO2 + N2) mixtures. The relative deviations with respect to experimental data for all (CO2 + N2) mixtures from the GERG-2008 were within the ±2.5% band, and the AGA8-DC92 EoSs were within ±3%. The Joule–Thomson inversion curve (JTIC) has also been modeled by the aforementioned EoSs, and a comparison was made between the calculated JTICs and the available literature data. The GERG-2008 and AGA8-92DC EoSs show good agreement in predicting the JTIC for pure CO2 and N2. The PR equation only matches well with the JTIC for pure N2, while it gives a poor prediction for pure CO2. For the (CO2 + N2) mixtures, the three equations all give similar results throughout the full span of JTICs. The temperature and pressure of the transportation and compression conditions in CCS are far lower than the corresponding predicted Pinv,max and Tinv,max for (CO2 + N2) mixtures.

Comparing the predictive ability of two- and three-parameter cubic equations of state in calculating specific heat capacity, Joule – Thomson coefficient, inversion curve and outlet temperature from Joule – Thomson valve

In this study, six cubic equations of state (CEoSs) were used to predict the Joule-Thomson coefficient (JTC), specific heat capacity (SHC), inversion curve (IC) and outlet temperature of the Joule-Thomson (JT) valve parameters. The accuracy of each CEoS was evaluated from the comparison of experimental data with obtained results. Of the six CEoSs, three-paramter CEoSs— Esmaeilzadeh and Roshanfekr (ER), Harmen and Knapp (HK), and Patel and Teja (PT)— were more accurate than two-paramter equations— Nasrifar and Moshfeghian (NM), Peng-Robinson (PR), and Soave-Redlich-Kwong (SRK). Ironically, original SRK showed the optimum accuracy in estimation of JTC. In addition, the Joule-Thomson inversion curves (JTIC) were plotted for pure gases. Most of the CEoSs showed reasonable prediction on low-temperature branch of JTIC, but only original SRK and PT CEoSs estimated well at high-temperature branch. For two-parameter CEoSs, the effect of employing different α-functions and adding volume translation factor were also examined. The error analysis showed that the accuracy of original PR CEoS was significantly improved when volume translation factor was included as a third parameter. In addition, the SRK-Twu88 and PR-Twu91 CEoSs showed higher accuracy in prediction of SHC as compared to original SRK and original PR.

Some studies on the mutual diffusion, Joule–Thomson inversion curve and virial coefficients of binary mixtures containing diethylamine and (C5 – C9) 1-alkanol

In this study, second and third virial coefficients and the Joule-Thomson inversion curves for the binary mixtures of diethylamine (DEA) with 1-pentanol up to 1-nonanol were calculated regarding the Peng-Robinson-Stryjek-Vera (PRSV) equation. Experimental densities were used to calculate the adjustable parameters of the PRSV equation. The estimation of the thermodynamic factor for the binary systems from the COSMO-RS model shows that the considered mixtures exhibit a negative deviation from Raoult's Law. Besides, the diffusion coefficients for the binary mixtures in the whole composition range were determined regarding experimental viscosities. The results were analyzed to gain information about the liquid structure in the binary mixtures. It has been shown that intermolecular forces between DEA and 1-alkanol, which changes with the alcohol chain length, have a significant impact on the above-mentioned parameters. The investigation has shown that increasing the alcohol chain length reinforces the strength of intermolecular interactions.

Predictions of the Joule-Thomson coefficients and inversion curves from the CPA equation of state

Several approaches involving some particular cubic equation of state (EoS) have been tested over the last 50 years as attempts to assess the Joule-Thomson coefficient (JTC) and inversion curves, though most of the cubic EoS are limited with regard to delivering good results for associating substances. The present work applies the Cubic Plus Association (CPA) EoS to predict the JTC for several pure substances (methane, ethane, propane, ethylene, benzene, toluene, nitrogen, carbon dioxide, sulfur hexafluoride, water, hydrogen sulfide and ethanol) and mixtures, focusing on systems with at least one associating substance. The results were compared with experimental and correlated data from the literature, as well as with the SRK EoS and molecular simulation. CPA EoS was capable of predicting the general trend for the Joule-Thomson coefficient and inversion curves even at extreme conditions, with reduced pressure values up to 20 and reduced temperatures up to 5.

Effects of natural gas compositions on its Joule–Thomson coefficients and Joule–Thomson inversion curves

The main goal of this study is to investigate the effect of natural gas composition on the Joule–Thomson coefficient and Joule-Thomson inversion curve. The Joule-Thomson inverse curve is the geometrical location of points where the Joule-Thomson coefficient is zero. The curve is an important parameter for the liquefaction capability of natural gas. The GERG-2008 equation of state is utilized to calculate the Joule-Thomson coefficient as well as the JT inversion curve. To validate the numerical values, the results are compared with measured values and the validation results show the GERG-2008 calculated Joule-Thomson inversion curve with high accuracy. The results show, that natural gases with larger molecular weights have higher pressures at the same temperature. Also, Based on GERG-2008 data, a novel correlation is presented for the calculation of the Joule-Thomson inversion curve. The correlation has an average absolute percent deviation of less than 2.5% in determining the natural gas Joule-Thomson inversion curve. It should be pointed out that for developing the correlation a huge database of 33,000 natural gas mixture is employed.

Prediction of Joule-Thomson coefficient and inversion curve for natural gas and its components using CFD modeling

In this study, three equations of state (EOS) in conjunction with computational fluid dynamics (CFD) modeling were used to predict the Joule – Thomson (JT) process behavior for natural gas and various pure gases. The JT effect is encountered in several industrial applications. The experimental determination of the JT coefficient (JTC) is complicated, and there is little gas pressure-volume-temperature (PVT) data available for estimating these JTC. Thus, the development of an efficient model to predict the JT effect in industrial processes is necessary. This study was carried out to attain a clear view of the single phase-flow of hydrocarbons and nitrogen in the JT process with CFD modeling. The JT valve was modeled in a pipe so as to predict the JTC, inversion curve (IC) and the isenthalpic curve of nitrogen, methane, ethane, propane and their mixtures in a wide range of temperature and pressure. Generally, the low-temperature branch of IC was predicted accurately by most of EOSs. Among the considered EOSs, Soave-Redlich-Kwong (SRK) EOS is able to predict more accurately the Joule – Thomson inversion curve (JTIC) in comparison with the other EOS. The validation of this CFD modeling was conducted using the experimental data from the literature and the industrial data of natural gas from an Iranian Gas Dehydration unit. The outlet temperature obtained from the CFD model agreed well with the industrial data of the JT process. The proposed CFD model accurately predicts the experimental and the industrial data of the JT process.

Evaluation of translated-consistent equations of state compared for the prediction of the Joule–Thomson effect at high pressures and high temperatures

In this research, Joule–Thomson coefficients for pure, binary, ternary, and multicomponent systems are predicted using translated and consistent versions of Peng-Robinson and Redlich-Kwong equations of state. The former is claimed to be certainly the most accurate and the safest three-parameter cubic equation of state ever published. The obtained results are compared with the predictions provided by Peng-Robinson, Soave-Redlich-Kwong, Volume Translated Peng-Robinson, Volume Translated Soave-Redlich-Kwong, and Patel-Teja-Valderrama equations of state along with different alpha functions, including Peng – Robinson original form (1976), Coquelet et al. (2004), Haghtalab et al. (2011), Saffari – Zahedi (2013), Soave – Redlich – Kwong original form (1972), Ozokwelu – Erbar (1987), Trebble – Bishnoi (1987), Nasrifar – Bolland (2004), and Pina – Martinez et al. (2019). Furthermore, the obtained results are compared to the available experimental data. Moreover, the performance of translated-consistent Peng-Robinson and translated-consistent Redlich-Kwong equations of state is determined at low pressures (60 atm) up to high pressures (360 atm) in comparison to the other equations of state. The dependency of the Joule – Thomson coefficient as a function of the mole fraction has been investigated. To compare better, Joule–Thomson inversion curves are also depicted for a variety of systems, containing pure, binary, ternary, and multicomponent mixtures. The obtained results are compared to the experimental data, correlated results, and molecular simulations.

Joule-Thomson coefficients and inversion curves from newly developed cubic equations of state

In this work, we have generalized different parametric forms of cubic equations of state (EoSs) to predict complete Joule-Thomson (J-T) inversion curves for methane at wide temperature and pressure ranges. EoSs of the Soave-Redlich-Kwong (SRK), Peng-Robinson (PR), Patel-Teja (PT), Esmaeilzadeh-Roshanfekr (ER) and the Hagtalab-Kamali-Mazloumi-Mahmoodi (HKMM) along with frequently used cohesion functions α(Tr) have been considered for plot of J-T inversion curves. The PR EoS along with different cohesion functions such as those of the Soave, Antonin Chapoy and the Tau-Sim-Tassone have been also tested for accurate prediction of the inversion curves. The four parametric EoSs of Adachi-Lu-Sugie (ALS), and Lawal-Lake-Silberberg (LLS) with their associated cohesion functions have been used for the prediction of J-T inversion curves. It has been observed that for the plot of inversion curves the LLS EoS is inadequate while the ER EoS agrees well with the previous measurements made in Laboratory. Besides, the J-T coefficient measurements from EoSs have been made for carbon dioxide and nitrogen gases at temperatures from 273.15 to 473.15 K and at pressures from 10 to 1000 atm, respectively. The uncertainties of experimental J-T coefficients data of carbon dioxide from values calculated using EoSs at constant pressure of 1 atm and 20 atm and with varying temperatures have been studied.

Thermodynamic properties of the 3D Lennard-Jones/spline model

The Lennard-Jones (LJ) spline potential is a truncated LJ potential so that both the pair potential and the force continuously approach zero at . We present a systematic map of the thermodynamic properties of the LJ spline model from molecular dynamics and Gibbs ensemble Monte Carlo simulations. Results are presented for gas/liquid, liquid/solid and gas/solid coexistence curves, the Joule-Thomson inversion curve, and several other thermodynamic properties. The critical point for the model is estimated to be and , respectively. The triple point is estimated to and . The coexistence densities, saturation pressure, and supercritical isotherms of the LJ spline model were fairly well represented by the Peng-Robison equation of state. We find that Barker-Henderson perturbation theory works less good for the LJ spline than for the LJ model. The first-order perturbation theory overestimates the critical temperature and pressure by about 10% and 90%, respectively. A second-order perturbation theory is not much better. Our assessment is that the mean compressibility approximation gives a poor representation of the second-order perturbation term. Our main conclusion is that we at the moment do not have a theory or model that adequately represents the thermodynamic properties of the LJ spline system.

Throttling process of the Kerr–Newman–anti-de Sitter black holes in the extended phase space

The throttling process of the Kerr-Newman-anti-de Sitter (KN-AdS) black holes is systematically studied in the extended phase space. In this framework, the cosmological constant is interpreted as a varying thermodynamic pressure, and the black hole mass is identified with enthalpy. The throttling process is essentially an isenthalpic (i.e., constant-mass) process for the KN-AdS black holes. The Joule-Thomson coefficient, inversion temperature, inversion curve, and isenthalpic curve are investigated in order, with both analytical and numerical methods. It is found that there are no maximum inversion temperatures, but only minimum ones that are around one half of the critical temperatures of the KN-AdS black holes. Two characteristic masses are also discussed to show the detailed features in the throttling behaviors of the KN-AdS black holes.

On the temperature dependence of the α function in the cubic equation of state

The cubic equation of state (EoS) is widely applied for modeling fluid thermodynamic properties in chemical processes. However, in the absence of a distinguishable reference property, the supercritical extrapolation of its only temperature-dependent parameter, the α function, resulted in nonphysical prediction of supercritical virial coefficients and heat capacities. From a theoretical perspective, we here rigorously derive the universal temperature-dependent behavior of the α function, using the generalized van der Waals theory without specifying the interaction potential. To isolate the behavior of the α function from the EoS structure, we examine the thermodynamic functions of realistic fluids at low densities. Our study reveals that the α function is finite, positive, and monotonically decreases with increasing temperature. We present a set of thermodynamic requirements and accordingly revise the predictive Soave and Twu α functions for the Redlich-Kwong and Peng-Robinson EoSs. Our study shows that the revised α functions avoid the divergent virial coefficients at infinite temperature, and the nonphysical bump on the heat capacity isobars immediately above the critical temperature, demonstrating the imperative need for thermodynamic requirements for the temperature dependence of the α function. Joule-Thomson inversion curve and vapor-liquid equilibria are also investigated.