Joule-Thomson Effect Research Articles

Heat transfer study in the exploitation of argillaceous‐silt natural gas hydrate reservoirs

AbstractThe paper investigates the heat transfer in the exploitation of offshore argillaceous‐silt natural gas hydrate reservoirs considering sand control. The temperature prediction model is established in this investigation. The coupled pressure‐temperature model of the flowing fluid inside the wellbore is also presented. The sand control for argillaceous‐silt natural gas hydrate reservoirs mainly brings two effects into the temperature and pressure profiles simulation, including the moderate sand control and the Joule–Thompson effect. The moderate sand control is reflected by the volume and particle size of produced sand into the wellbore in the mathematical derivation. The Joule–Thompson is considered in the model due to the small diameter of sand control screens. The experiment is designed to measure the pressure drop caused by various mesh diameters of sand control screens. Subsequently, the regression relationship between the pressure drop and the mesh diameter is concluded to calculate the temperature change at the sand control screen. The simulation of heat transfer helps to analyze secondary hydrate formation risk in the wellbore. The proposed model identifies the high‐risk location of the secondary hydrate formation. The sand control effect and well geometry effect are discussed quantitatively. The strict sand control in the argillaceous‐silt natural gas hydrate (NGH) sediment exploitation reduces the risk of secondary hydrate formation significantly; however, it also has a negative effect on natural gas production. To balance the sand control and the prevention of secondary hydrate formation risk, it is suggested to install the heating electrode in the high‐risk location to ensure flow safety with acceptable sand control precision. The heat provided by heat electrodes is calculated by the model presented in this paper. The model can be used to determine the proper arrangement of heat electrodes. The paper also describes the secondary hydrate formation by adjusting the well geometry. The formation depth of the NGH reservoir and the sea interval should be considered in the risk analysis of the secondary hydrate formation. Additionally, the effects of wall thickness and wall thermal properties are evaluated and discussed. It is recommended to optimize the riser thickness with a small thermal conductivity value to minimize the secondary hydrate formation risk, which is more efficient compared to adjusting the cement sheath.

Thermal recovery of coalbed methane: Modeling of heat and mass transfer in wellbores

Coalbed methane (CBM) reservoirs have the characteristics of low porosity, low permeability, strong heterogeneity and high content of adsorbed gas. A large number of studies have shown that the adsorption performance of coalbed methane reservoirs on methane is significantly affected by temperature. Therefore, heat injection development of coalbed methane reservoirs has received extensive attention. This paper takes the superheated steam (SS) flow in the wellbore after fracturing the coalbed methane reservoir as the research object, and establishes a mathematical model of the SS flow. The model consists of momentum conservation equation and energy conservation equation as the main control equation, combined with auxiliary models to form a complete mathematical model. In this paper, the discrete method is used to obtain the numerical solution of the model, and then the influence of the injection parameters on the SS flow is analyzed. The research conclusions of this paper have reference significance for the development of coalbed methane reservoirs with SS injection. This study found that: (a) When the injection rate is low enough (0.2 kg/s in this paper), the effect of gravity on SS pressure is stronger than that of pressurized gas; (b) When the steam injection speed is within a certain range (0.5 kg/s in this example), the pressure of the SS first decreases and then increases, forming a U shape; (c) The SS temperature increases with increasing of injection rate. During this period, the Joule-Thompson effect replaces the heat loss effect as the main factor controlling the temperature drop of the SS; (d) In order to maintain the development advantages of SS, the SS should still have a certain degree of superheat at the bottom of the well. Therefore, the steam injection speed should not be too high (eg 0.2 kg/s in this article); (e) Therefore, with the increase of SS pressure inside the wellbore, the temperature value decreases due to the influence of Joule Thompson effect, resulting in the continuous decrease of superheat degree.

Mathematical Model of the Process of Non-Equilibrium Hydrate Formation in a Porous Reservoir during Gas Injection

Increasing the efficiency of natural gas storage in geological formations is possible by transferring gas from a free state to a gas hydrate state, since gas hydrates have a number of unique properties. For example, 1 m3 of methane hydrate contains 164 m3 of gas under normal conditions. It is possible to store a sufficiently large amount of gas in a small volume at a relatively low pressure. To study the regularities of the process of formation of underground gas hydrate gas storage, this article presents a mathematical model of the process of methane injection into a natural reservoir saturated with methane and water, accompanied by the formation of gas hydrate. Unlike previous works, the constructed mathematical model additionally takes into account a number of factors: the filtration flow of water, the real gas properties, the Joule–Thomson effects and adiabatic compression. The process of gas hydrate formation is considered as a non-equilibrium phase transition. Numerical solutions of the problem are constructed that describe the distributions of parameters (temperature, pressure, phase saturations) in a reservoir. Dependences are obtained that reveal the regularities of the process of non-equilibrium formation of gas hydrate in a natural reservoir during gas injection. The influence of gas injection pressure and temperature, as well as reservoir porosity and permeability, on the distributions of pressure, temperature, water saturation and hydrate saturation in the reservoir, as well as on the dynamics of changes in these parameters and the mass of gas hydrate formed in the reservoir over time, are analyzed.

Evaluation of cubic, PC-SAFT, and GERG2008 equations of state for accurate calculations of thermophysical properties of hydrogen-blend mixtures

Hydrogen (H2) is a clean fuel and key enabler of energy transition into green renewable sources and a method of achieving net-zero emissions by 2050. Underground H2 storage (UHS) is a prominent method offering a permanent solution for a low-carbon economy to meet the global energy demand. However, UHS is a complex procedure where containment security, pore-scale scattering, and large-scale storage capacity can be influenced by H2 contamination due to mixing with cushion gases and reservoir fluids. The literature lacks comprehensive investigations of existing thermodynamic models in calculating the accurate transport properties of H2-blend mixtures essential to the efficient design of various H2 storage processes. This work benchmarks cubic equations of state (EoSs), namely Peng–Robinson (PR) and Soave Redlich–Kwong (SRK) and their modifications by Boston–Mathias (PR-BM) and Schwartzentruber–Renon (SR-RK), for their reliability in predicting the thermophysical properties of binary and ternary H2-blend mixtures, including CH4, C2H6, C3H8, H2S, H2O, CO2, CO, and N2, in addition to Helmholtz-energy-based EoSs (i.e., PC-SAFT and GERG2008). The benchmarked models are regressed against the experimental data for vapor–liquid equilibrium (VLE) that covers a wide range of pressures (0.01 to 101 MPa), temperatures (92 K to 367 K), and mole fractions (0.001 to 0.90) of H2. The novelty of this work is in benchmarking and optimizing the parameters of the mentioned EoSs to study VLE envelopes, densities, and other critical transport properties, such as heat capacity and the Joule–Thomson coefficient of H2 mixtures in a wide range of associated conditions. The results highlight the significant effect of the temperature-dependent binary interaction parameters on the calculations of thermophysical properties. The SR-RK EoS demonstrated the highest agreement with VLE data among the cubic EoSs with a low root mean square error and absolute average deviation. The PC-SAFT VLE models demonstrated results comparable to the SR-RK. The sensitivity analysis highlighted the high influence of impurity on changing the thermophysical behavior of H2-blend streams during the H2 storage process.

Study of combined heat and power plant integration with thermal energy storage for operational flexibility

Increasing the share of renewable energy in the future electricity market requires measures to maintain the stability of the grid, owing to the volatility and intermittency of renewable energy. For a combined heat and power (CHP) plant, molten salt thermal energy storage (TES) can be added to improve the flexibility to meet the needs of peak shaving. This paper proposed a novel cascade reheat steam extraction system to adjust the electrical load by using EBSILON software applied to thermal simulation and thermal analysis. A 350 MW supercritical CHP plant was used as an example to analyze the thermal and peak shaving performance under variable operating conditions. Meanwhile, through the static simulation, the change in the load and the efficiency of TES can be calculated during the charging and discharging cycle. The results show that the efficiency of TES is 40–51 %. With an increase in the load, the efficiency of TES is reduced, and the exergy loss range is from 4 MW to 12.4 MW mainly due to the throttling process and the molten salt heat transfer process. Moreover, the thermal efficiency and exergy efficiency of the novel system are higher than those of the traditional CHP plant below 60 % turbine heat acceptance, so it is relatively economical to run for peak shaving under low loads. Finally, depending on the corresponding operating strategy, a reduction of the minimum load by up to 1 % of the rated output electrical load during charging and an increase of the maximum load by up to 2 % of the rated output electrical load during discharging are possible. Overall, the proposed system provides a feasible method for the flexibilization of CHP plants alongside new renewable systems.

Effect of polarity on prediction of second order derivative thermodynamic properties of refrigerants

In this research, the SAFT-VR Morse has been extended to polar system by considering the dipolar interactions between non-spherical molecules. The second order derivative thermodynamic properties of refrigerants such as speed of sound, specific heat capacity and Joule-Thomson coefficient have been predicted and compared to PPC-SAFT EoS. The model parameters have been obtained using vapor pressure and saturated liquid density data of pure refrigerants. Using obtained model parameters the aforementioned properties have been predicted in the vapor, liquid, saturation and supercritical phases. The effect of polar contribution on model prediction performance has been studied. The results show that, the polar contribution can be neglected without losing model accuracy. The obtained average error of the polar PC-SAFT and polar SAFT-VR Morse is very close to their original versions. As well, the PPC-SAFT EoS gives accurate results compared to SAFT-VR Morse and its polar version, especially in the case of Joule-Thomson coefficient prediction.

Cooling performance of Joule Thomson coolers with straight heat exchangers for space science missions

Space-qualified Joule Thomson coolers with significant cooling power below 5K enable a variety of missions, which include large infrared space telescopes, superconducting detectors for astrophysics, and quantum applications. In JAXA, a 4K-class Joule–Thomson cryocooler (4K-JT) and a 1K-class Joule–Thomson cryocooler (1K-JT) have been developed with the required cooling power of 40mW at 4.5K and 10mW at 1.7K respectively, for upcoming next-generation space missions. This paper reports the results of cooling performance tests of these JT coolers with straight heat exchangers. A straight heat exchanger is desirable in several space science missions, including the Space Infrared Telescope for Cosmology and Astrophysics (SPICA), while the coiled type of heat exchanger was used in past missions. The effectiveness of the heat exchanger is strongly affected by its shape and length, and the effectiveness significantly influences the cooling power and the cooling efficiency of the Joule–Thomson cooler. This study designed, fabricated and measured several types of heat exchanger test models. The effect of gravity and the thermal environment on cooling performance are also reported.

Simultaneous formic acid production by hydrothermal CO2 reduction and biomass derivatives conversion in a continuous reactor

The reduction of CO2 to obtain formic acid in hydrothermal media can contribute to the reduction and valorization of CO2 emissions, but in order to apply it industrially, scalable continuous-flow reactors must be developed. In this work, a continuous flow reactor is developed that can process up to 1.2 L/h of bicarbonate solution. Glucose as model compound of the products of the hydrothermal decomposition of lignocellulosic biomass is used as reducing agent. Feed stream is suddenly heated at the inlet of the reactor by mixing it with a preheated water stream and instantaneously cooled after the reactor by decompression Joule-Thompson effect, allowing a precise control of the residence time and enabling to apply short residence times down to 1 s that are not feasible in batch reactors. Several operational parameters, as residence time, temperature and additives, were studied. Yields to formic acid up to 63 % were achieved at 300 °C with residence times lower than 1 min. In order to better understand the process, NaH13CO3 was used in selected experiments to check if the origin of formic acid was the reduction of bicarbonate or the hydrolysis of glucose It was found that almost 50 % of formic acid was produced due to the reduction of NaHCO3 after 10 min of reaction, a proportion significantly higher than that observed in batch experiments at similar reaction times. Furthermore, experiments performed without NaHCO3 or with other alkaline buffers demonstrate that NaHCO3 also promotes the transformation of glucose into formic acid, increasing the overall selectivity of the process and facilitating downstream processing.

Effects of external temperature and dead volume on laboratory measurements of pore pressure and injected volume in a rock fracture

The accurate evaluation of pore pressure and injected volume is crucial for the laboratory characterization of hydromechanical responses of rock fractures. This study reports a series of laboratory experiments to systematically demonstrate the effects of external temperature and dead volume on laboratory measurements of pore pressure and injected volume in a rock fracture. We characterize the hydraulic aperture of the fracture as a function of effective normal stress using the exponential aperture model. This model is then employed to predict the pore pressure change and injected volume in the fracture without the influences of external temperature and dead volume. The external temperature changes in the cyclic loading test due to the Joule-Thompson effect for fluids. The effect of external temperature on pore pressure change in the fracture can be well explained by thermal pressurization of fluids. Our results also show that the external dead volume can significantly lower the pore pressure change in the fracture during the cyclic loading test under undrained conditions. The injected volume can also be substantially enlarged due to the external dead volume in a typical pore pressure system. Internal measurement of the pore pressure in the fracture using a fiber optic sensor cannot exclude the influences of external temperature and dead volume, primarily because of the good hydraulic communication between the fracture and pore pressure system. This study suggests that the effects of external temperature and dead volume on pore pressure response and injected volume should be evaluated for accurate laboratory characterization and inter-laboratory comparison.

Magnetic black holes in AdS space with nonlinear electrodynamics, extended phase space thermodynamics and Joule–Thomson expansion

This paper studies thermodynamics of magnetically charged black holes in Anti-de Sitter space in an extended phase space. The cosmological constant is considered as a pressure and the black hole mass is treated as the chemical enthalpy. The black hole thermodynamics is similar to the Van der Walls liquid–gas thermodynamics. Quantities conjugated to the nonlinear electrodynamics parameter and a magnetic charge are obtained. The first law of thermodynamics and the generalized Smarr relation take place. We investigate critical behavior of black holes and Joule–Thomson expansion. The Gibbs free energy, the Joule–Thomson coefficient and the inversion temperature are calculated.

Overview of thermodynamical properties for Reissner–Nordström–de Sitter spacetime in induced phase space

Since the black hole and cosmological horizons in the de Sitter (dS) spacetime with the Reissner–Nordström (RN) black hole are not independent with each other, which is caused by the gravitational effect, the interplay between two horizons should be considered. Based on this, by introducing the interactive entropy the RN–dS spacetime is analogous to a thermodynamic system with various thermodynamic quantities, in which the laws of thermodynamics still hold on. In our work, the thermodynamic properties of the RN–dS spacetime are mapped out in the induced phase space, which are similar to that in AdS black holes. The phase transition of the RN–dS spacetime between the high-potential and the low-potential black hole phases is observed. Compared with an ordinary thermodynamic system, the similar behaviors about the Joule–Thomson expansion and the critical exponents are also checked out. Finally, the scalar curvatures of two existent phases are presented to reveal the underlying microstructure and nature of phase transition in the RN–dS spacetime, which opens a new window to investigate the dS spacetime with black holes from an observational perspective.

Black holes in a cavity: Heat engine and Joule-Thomson expansion

We consider the charged d-dimensional black holes in the cavity in extended phase space and investigate the heat engine and the Joule-Thomson (JT) expansion. Since the phase structure of black holes in the cavity is similar to anti-de-sitter (AdS) cases, we take black holes in a cavity as the working substance in the heat engine and calculate their efficiency in Carnot cycle and rectangular cycle. Also, we discuss whether the JT expansion of charged black holes in the cavity is consistent with AdS cases and find the charged black hole in a cavity always cools down during the isenthalpic process with the decreasing pressure.

Численное моделирование процессов дросселирования прямоточного воздушно-реактивного двигателя

Aimed at determining the maximum allowable pressure in the combustion chamber causing no flow separation in the air intake device, numerical simulation of the throttling process in a ramjet engine was carried out. Calculations were made in two formulations: with local and global time steps. When comparing results obtained using these approaches, the possibility was found to determine the air intake device throttling characteristics without losing the accuracy at the initial stages of designing the ramjet engines with introduction of the local time step. The non-stationary model created the basis for selecting the optimal integration step to minimize computational resources. The flow pulsations period was evaluated for the event of a surge. These pulsations frequencies were registered in the extremely low frequency range.

Study on two microchannel coolers with different coupling mechanisms of distributed J-T effect and heat transfer

As a typical characteristic of the microchannel Joule-Thomson (J-T) coolers, the distributed J-T effect significantly impacts the cooling effect. To investigate the coupling mechanism of distributed J-T effect and heat transfer, two micro-coolers are fabricated by Printed Circuit Board (PCB) technology in this study. The throttling device is removed from the micro-cooler with staggered etched pillars (Cooler-Pillars), resulting in an entire coupling of heat recovery and throttling processes. The heat recovery and throttling structures are preserved in a micro-cooler etched with rectangular microchannels (Cooler-REC), and the two processes couple partly. The performance of the two micro-coolers is investigated experimentally and numerically at the inlet pressure of 2.02∼5.12 MPa. The experimental results show that the mass flow rate and total pressure drop of Cooler-Pillars are higher than Cooler-REC at the same inlet pressure. Compared with Cooler-REC, Cooler-Pillars can reach a lower cold end temperature and has a cold-end temperature of 190.6 K in steady-state operation at 5.03 MPa. A steady-state mathematical model is developed and compared favorably with the experimental results. The simulation result shows that at the same inlet pressure, the overall distribution of J-T coefficients and the total temperature drop caused by distributed J-T effect of Cooler-Pillars are higher. It is also found that the overall Nu distribution of Cooler-Pillars is higher than Cooler-REC, and heat transfer is enhanced, leading to an increase of 64.5% in average unit heat transfer at 5 MPa.

Thermal stability with emission energy and Joule–Thomson expansion of regular BTZ-like black hole

We investigate the thermodynamic properties and Joule–Thomson expansion for conical or BTZ-like black holes. To analyze the thermal stability, we discuss the temperature and thermal stability relative to the horizon radius for different values of model parameters beta _0 and alpha _2. Moreover, we analyze thermodynamical geometries like Ruppeiner, Weinhold and Hendi Panahiyah Eslam Momennia formulation and calculate respective scalar curvatures for BTZ-like black holes. Interestingly, the black holes have no singularity in some cases, i.e., completely regular. We obtain the inversion temperatures and inversion curves and investigate the similarities and differences between van der Waals and charged fluids. To discuss this expansion, we use a BTZ-like black hole. Further, we establish the position of the inversion point versus different values of mass mu , and the parameters beta _0 and alpha _2 for such a BTZ-like black hole. The Joule–Thomson coefficient mu at this point disappears. A crucial trait upon which we relied to inspect the sign of quantity mu to get the cooling-heating areas. We also investigate the energy emission depending upon the frequency omega .

Joule-Thomson expansion of AdS black holes in quasitopological electromagnetism

We study the Joule-Thomson expansion in Einstein-Maxwell theory supplemented with the so-called quasitopological electromagnetism, this in the extended phase space thermodynamic approach. We compute the Joule-Thomson coefficient and depict all relevant inversion and isenthalpic curves in the temperature-pressure plane, determining in this manner the corresponding cooling and heating regions. In contrast with previous related works we show the existence of three branches for the inversion curves which depends on suitable selections of the parameter space of the theory, thus departing from the usual van der Waals behavior which exhibits up to two branches.

Numerical simulation of flow and heat transfer performance during supercritical water injection in vertical wellbore: A parameter sensitivity analysis

Supercritical water injection is a promising technology for heavy oil thermal recovery. Predicting and regulating the thermophysical parameters of supercritical water at bottomhole are the prerequisite for achieving high recovery efficiency. In this paper, a novel numerical model was proposed to simulate wellbore flow and heat transfer of supercritical water injection. A modified correlation of frictional coefficient was developed to calculate water flow resistance near its critical point, where its properties change abruptly. The unsteady heat loss to the formation was calculated directly by solving two-dimensional unsteady heat conduction equations. They were respectively coupled in momentum and energy balance equations using an iterative scheme. This model was proved to be accurate by two oilfield cases in which the relative errors of wellbore fluid pressure and temperature are less than 1%. Then parameters sensitivity analysis of the injection pressure, temperature, mass flux and the apparent heat conductivity of insulating tube was conducted. The results indicated that the temperature variation of wellbore fluid depended on both enthalpy drop (or heat loss) and Joule-Thomson effect. An abnormal phenomenon that the fluid temperature increased with wellbore depth near the critical and pseudo-critical points was found because of the sudden increase in high heat capacity and Joule-Thomson coefficient of water. Raising the bottomhole fluid temperature was the key to enhanced oil recovery by supercritical water injection. Low apparent heat conductivity of insulating tube contributed richly to raise bottomhole fluid temperature by enlarging thermal resistance and reducing wellbore heat loss. There existed an optimal mass flux for maximizing bottomhole temperature, because when the mass flux increased, the shortened resident time within wellbore and the decreased fluid pressure favored temperature increase and decrease respectively. Selecting an injection pressure near the critical or pseudo-critical point and raising the injection temperature would increase the bottomhole temperature and reduce relative fluid heat loss.

Controlling hydrocarbon dew point and water dew point of natural gas using Aspen HYSYS

A great attention is subjected to the environmentally friendly natural gas. Compared to other fossil fuels, natural gas is a cleaner burning due to the lower emission of carbon dioxides into the air. Removal of associated hydrocarbons from natural gas streams plays an important role to sell and to achieve the pipeline specification of natural gas. To satisfy the specification of pipelines, the hydrocarbon dew point and water dew point of natural gas must be controlled below the pipeline operating conditions to prevent many problems: two-phase flow and hydrate formation in the system. The main purpose of this paper is to simulate the gas plant process to study the effect of natural gas composition and changing in differential pressure of Joule–Thomson expansion valve on the obtained values of hydrocarbon, water dew points, and cricondentherm temperature.The results of process simulation using Aspen HYSYS have shown that the control of hydrocarbon dew point, water dew point, and cricondentherm of natural gas is achieved through increasing the Joule-Thomson valve differential pressure. There is an inverse relation between increasing Joule-Thomson valve differential pressure (∆p) and hydrocarbon dew point, water dew point, and cricondentherm to meet the specification of gas pipeline transmission. Increasing differential pressure (∆p) from 14 bar to 24 bar causes a decrease in hydrocarbon dew point, water dew point from −1 to −26°C and from 0 to −18°C, respectively. Cricondentherm is also decreased from 4 to −12°C by increasing differential pressure (∆p) from 14 to 24 bars. The operating conditions at differential pressure below 14 bar is not advisable because cricondentherm temperature does not meet the specification of gas pipeline transmission and hence lead to many problems. Careful adjustment of the operating conditions of gas processing plant is very important by making such simulations to choose the optimum operating conditions which meet gas pipeline transmission.

AdS Black Holes in the Framework of Nonlinear Electrodynamics, Thermodynamics, and Joule–Thomson Expansion

The thermodynamics and phase transitions of magnetic Anti-de Sitter black holes were studied. We considered extended-phase-space thermodynamics, with the cosmological constant being a thermodynamic pressure and the black hole mass being treated as a chemical enthalpy. The extended-phase-space thermodynamics of black holes mimic the behavior of a Van der Waals liquid. Quantities conjugated to the coupling of nonlinear electrodynamics (NED) and a magnetic charge are obtained. Thermodynamic critical points of phase transitions are investigated. It was demonstrated that the first law of black hole thermodynamics and the generalized Smarr relation hold. The Joule–Thomson adiabatic expansion of NED-AdS black holes is studied. The dependence of inversion temperature on pressure and the minimum of the inversion temperature are found.

Joule–Thomson expansion of 5-dimensional [formula omitted]-charged black holes

In this article, we study the Joule–Thomson expansion for a given number of electric charges for 5-dimensional R-charged black holes in the extended phase space. We analyze both the isenthalpic and numerical inversion curves in the T−P plane and show the cool-heat zones associated with 5-dimensional R-charged black holes. A concrete comparison of Joule–Thomson expansion comes from the relationship between minimum inversion and critical temperatures for 5-dimensional R-charged black holes.