Injection Of Liquid Carbon Dioxide Research Articles

Study of regimes for methane - carbon dioxide replacement in natural gas hydrates by liquid carbon dioxide injection into a porous stratum

A developed mathematical model offers a study of methane-carbon dioxide replacement in gas hydrate through injection of liquid carbon dioxide into a porous stratum with final sizes. Depending on the parameters of injected carbon dioxide flow and depending on the stratum boundary conditions, the process of formation of the gas hydrate comprising carbon dioxide can occur through methane replacement in the gas hydrate or through the formation of zones with free methane and water. The critical diagrams are presented that map the conditions for both regimes.

Numerical approach of liquid carbon dioxide injection in crushed coal and its experimental validation

The safety issues are a major restriction on coal mining and growing efforts are being made in the search for solutions that will guarantee sustainable use of energy resources. Liquid carbon dioxide is attracting particular interest of coal fire-fighting due to the promising efficiency of cooling and asphyxia. Our objective is to develop a valid model to simulate the dispersion and thermal behaviors of liquid carbon dioxide under crushed coal condition and assessment of liquid carbon dioxide injection for coal fire-fighting. For this purpose, a numerical approach which requires an accurate state equation for calculating physical parameters of carbon dioxide, also accounts for appropriate description of energy transformation during the injection is presented. The validation of such a model against three experimental tests on temperature variation is proposed, and the model has proved capable of accurately predicting the heat and mass transfer process when liquid carbon dioxide is injected into crushed coal. Furthermore, the impact of nozzle diameter on the dispersion and thermal behaviors of liquid carbon dioxide is extensively investigated.

Mathematical Model of Decomposition of Methane Hydrate during the Injection of Liquid Carbon Dioxide into a Reservoir Saturated with Methane and Its Hydrate

The article describes a mathematical model of pumping of heated liquid carbon dioxide into a reservoir of finite extent, the pores of which in the initial state contain methane and methane gas hydrate. This model takes into account the existence in the reservoir of three characteristic regions. We call the first region “near”, the second “intermediate”, and the third “far”. According to the problem statement, the first region contains liquid CO2 and hydrate, the second region is saturated with methane and water, the third contains methane and hydrate. The main features of mathematical models that provide a consistent description of the considered processes are investigated. It was found that at sufficiently high injection pressures and low pressures at the right reservoir boundary, the boundary of carbon dioxide hydrate formation can come up with the boundary of methane gas hydrate decomposition. It is also shown that at sufficiently low values of pressure of injection of carbon dioxide and pressure at the right boundary of the reservoir, the pressure at the boundary of hydrate formation of carbon dioxide drops below the boiling pressure of carbon dioxide. In this case, for a consistent description of the considered processes, it is necessary to correct the mathematical model in order to take into account the boiling of carbon dioxide. Maps of possible solutions have been built, which show in what ranges of parameters one or another mathematical model is consistent.

Modeling of dispersion behaviors during the injection of liquid carbon dioxide in pulverized coal with experimental validation

This article presents a model for investigating the thermo- and fluid-dynamical behaviors of liquid carbon dioxide (LCO2) in pulverized coal, which is coupling of phase transition, multiphase flow, heat and mass transfer. In the model, the intensive non-isothermal effect caused by phase transition during the injection process is considered as a negative heat source associated with transient latent heat and the temperature–dependent physical parameters based on Span–Wagner equations are employed. By comparison with the data from model predictions and test under various nozzle diameters, the proposed model has been validated against experimental results from temperature variation. In addition, the dispersion behaviors of LCO2 in pulverized coal are extensively studied. The presented research provides a viable method for the prediction of dispersion and thermal behaviors when LCO2 is used for underground coal fires prevention and mitigation.

Experimental investigation of the impact of liquid carbon dioxide injection on temperature in pulverized coal

AbstractUsing liquid carbon dioxide (LCO2) as a medium for underground coal fires prevention and control, while reducing the emissions of CO2, is a promising option for CO2 utilization worldwide. However, the mechanism of LCO2 flow with phase transition on coal temperature is still not clear. In this work, an experimental system was designed and fabricated to investigate the phase transition behavior and temperature variation during injecting LCO2 into pulverized coal and the impact of mass flow rate, nozzle diameter, and injection pressure on cooling effect. The results indicate that when LCO2 was injected into the pulverized coal, the instantaneous phase change into solid and vapor occurred just after leaving the release port. An intensive heat transfer process occurred because of the throttling effect, flashing effect, and sublimation and thereby formed a cooling area (<−56.6°C), which was the main area of cooling effect and phase transition; as injection time increases, the range of this area increases in the form of logarithmic function. In addition, the cooling area exhibited a strong dependence on the injection conditions, and its correlation with mass flow rate, nozzle diameter, and injection pressure are identified as exponential, logarithmic, and linear relationship by dimensionless analysis, respectively. Meanwhile, an empirical formula was developed for calculating the cooling effect under various injection conditions. In summary, the experiments provided fundamental data and regime for predicting the effect of LCO2 injection on the temperature of pulverized coal, which can be used to guide the utilization of LCO2 for coal fires prevention. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd.

Micro-pilot test for optimized pre-extraction boreholes and enhanced coalbed methane recovery by injection of liquid carbon dioxide in the Sangshuping coal mine

The extraction efficiency of high-gas coal seams is low in China with a large number of pre-drainage boreholes. In this study, we analyze the coal seam gas displacement mechanism using liquid carbon dioxide by combining theoretical analysis, experiments, and field tests. Changes of gas displacement efficiency with time under different displacement flow and pressure conditions are determined. We propose a coalbed methane displacement method using liquid carbon dioxide and apply the model in a field test carried out in well No. 2 of the Sangshuping coal mine. The results show that the injection of liquid carbon dioxide in coal seams is a pressure swing adsorption process. The effective displacement radius from the in-situ tests reaches 20 m. The maximum CH4 extraction concentration in the test area is 65%, which is 2.41 times higher than that of the original coal seam (27%). The maximum methane extraction flux rate is 0.884 m3/min, which is 2.34 times that of original coal seam (0.377). Implementation of liquid carbon dioxide displacement coalbed methane technology optimizes borehole arrangement and enhances coalbed methane extraction.

Hydrate Formation in a Porous Medium during the Injection of Liquid Carbon Dioxide with Allowance for Its Boiling

The specific features of gas hydrate formation during the injection of liquid carbon dioxide into a porous medium saturated with methane and water with allowance for the boiling of carbon dioxide have been studied. It has been found that the formation of carbon dioxide hydrate can occur both on the frontal boundary and in the extended region. It has been shown that the boiling of carbon dioxide and the corresponding cooling of a reservoir facilitate the formation of carbon dioxide hydrate on the frontal surface. Curves have been constructed that separate different regimes depending on injection pressure, initial pressure, and reservoir permeability.

Gas hydrate formation of sulfur dioxide by injection of liquid carbon dioxide into a natural layer saturated with methane and ice

A mathematical model of injection of liquid sulfur dioxide into a natural layer saturated with ice and methane, accompanied by the formation of SO2 gas hydrate on the front surface is presented. The case when the initial state of the system, as well as the pressure and temperature of the injected liquid sulfur dioxide correspond to the thermobaric conditions of the existence of sulfur dioxide gas hydrate is considered. That, the formation of sulfur dioxide gas hydrate occurs on the front surface, coinciding with the surface of methane displacement by sulfur dioxide. In this case, two characteristic zones are formed in the layer. In the first (near) zone the pores are saturated with sulfur dioxide and its gas hydrate, in the second (far) zone it is saturated with ice and methane. The dependences of the temperature and the coordinates of the formation border of sulfur dioxide gas hydrate on the injection pressure are explored. It is established that the injection pressure increase causes the rise in temperature and movement speed of the surface of the formation of sulfur dioxide gas hydrate. It is shown that at sufficiently high values of injection pressure and initial layer temperature, the temperature rises above the ice melting temperature at the formation border of sulfur dioxide gas hydrate. This corresponds to the formation of an intermediate region saturated with a mixture of water and methane. It is determined the dependence of the limit value of the sulfur dioxide injection pressure, above which an intermediate region saturated with a mixture of water and methane appears on the initial layer temperature.

ИНЖЕКЦИЯ ЖИДКОГО ДИОКСИДА УГЛЕРОДА В ПЛАСТ, НАСЫЩЕННЫЙ МЕТАНОМ И ЕГО ГАЗОГИДРАТОМ

Актуальность исследования связана с разработкой теоретических основ технологий добычи газа из газогидратных месторождений методом замещения. Рассматривается метод инжекции диоксида углерода, позволяющий значительно снизить энергетические затраты на разработку природных газогидратных залежей. Целью исследования является выяснение особенностей протекания процесса замещения метана диоксидом углерода в газогидрате при инжекции жидкого диоксида углерода в газогидратный пласт. Объект: пористый пласт конечной протяженности, насыщенный метаном и его газогидратом, исходные давление и температура которого соответствуют условиям стабильного существования газогидрата метана. Методы. На основе уравнений механики сплошной среды построена математическая модель тепломассопереноса в природном пласте, сопровождающаяся замещением метана на диоксид углерода в газогидрате. Принято, что в рассматриваемом случае в пласте возникают две характерные зоны, разделенные подвижной границей фазовых переходов. В первой (ближней) зоне поры насыщены жидкой двуокисью углерода и ее газогидратом, а во второй (дальней) зоне содержатся метан и его газогидрат. Результаты. Получены численные решения для полей давления и температуры при инжекции жидкого диоксида углерода в газогидратный пласт конечной протяженности. Построены зависимости температуры на границе замещения от давления инжекции и проницаемости пласта. Установлено, что при достаточно низких значениях давления инжекции и проницаемости величина температуры на границе замещения может подниматься выше равновесного значения температуры диссоциации газогидрата метана на газ и воду. Это соответствует возникновению второй подвижной межфазной границы, на которой происходит разложение газогидрата метана. Найдена зависимость предельной температуры закачиваемой жидкой двуокиси углерода, выше которой необходимо учитывать образование смеси метана и воды, от значений давления на правой и левой границах пласта и его проницаемости. Установлено, что режим с разложением газогидрата реализуется при высоких значениях давления на правой границе пласта и низких значениях проницаемости и давления, под которым закачивается двуокись углерода. Получены зависимости скорости границы замещения, а также времени полной замены газогидрата метана на газогидрат диоксида углерода во всем пласте от давления на правой и левой границах пласта, а также от его проницаемости.

Mathematical model of injection of liquid carbon dioxide in a reservoir saturated with methane and its hydrate

Based on the equations of mechanics of multiphase media, a mathematical model of the injection of liquid carbon dioxide into a natural reservoir saturated with methane and its gas hydrate is constructed. Numerical solutions for two different flow regimes are obtained and investigated. In the first regime, methane is replaced by carbon dioxide in the gas hydrate without the release of free water. In the second mode, gas hydrate decomposes into methane and water, and further formation of CO2 gas hydrate from water and carbon dioxide occurs. Numerical calculations show that the first mode is realized at low values of permeability and injection pressure, as well as high values of the temperatures of injected carbon dioxide, initial temperature of the reservoir and pressure at the right boundary of the reservoir. For each regime, the conditions under which the pressure in the liquid carbon dioxide filtration region can drop below the equilibrium boiling point of CO2 are investigated. Numerical calculations show that this is possible at low injection pressures and pressures at the right boundary of the reservoir. Critical diagrams were constructed that determine the “injection pressure-pressure on the right-hand boundary of the reservoir”, “injection pressure-permeability”, “injection pressure-injection temperature” and “injection pressure-initial temperature of the reservoir” in the region of existence of four qualitatively different flow regimes.

Formation of a Mixed Region of Carbon Dioxide and Methane Hydrates during the Injection of Liquid Carbon Dioxide to a Reservoir Saturated with Methane and Water

Based on the equations of continuous medium mechanics, a mathematical model is constructed for the injection of liquid carbon dioxide into the porous medium saturated with methane and water for the case when the injection is accompanied by the formation of gas hydrates of carbon dioxide and methane. Self-similar solutions to the one-dimensional problem describing the evolution of hydrodynamic and temperature fields are constructed. The dynamics of movement of frontal boundaries of phase transitions with respect to injection pressure and temperature, as well as with respect to permeability and initial pressure of the porous medium is investigated. It is shown that intensity of the formation of methane and carbon dioxide gas hydrates increases with an increase in injection pressure and reservoir permeability, and at rather high values of permeability, pressure drop in the reservoir and injection temperature, the frontal formation boundaries of methane and carbon dioxide gas hydrates may merge. The dependence of the limit values of injection pressure and temperature corresponding to the merger of the phase transition boundaries on the permeability and initial pressure is studied in this work.

Formation of a region of mixture of the carbon dioxide and methane hydrates by liquid carbon dioxide injection into the layer saturated with methane and water

Formation of a region of mixture of the carbon dioxide and methane hydrates by liquid carbon dioxide injection into the layer saturated with methane and water

Injection of liquid carbon dioxide into a gas hydrate reservoir

This paper presents the results of mathematical modeling of liquid carbon dioxide injection into a porous reservoir of a finite length, initially saturated with methane and its hydrate. Calculations show that when forming the carbon dioxide hydrate, different situations are possible: an area is formed, saturated with water and methane; and such area is absent in a porous medium. It has been established that the main parameters determining the different hydrate formation regimes are the temperature and pressure of the injected carbon dioxide, as well as the reservoir permeability.

Formation of CO2 hydrate in a porous reservoir at the liquid carbon dioxide injection taking into account its boiling

The theoretical study results of the CO2 hydrate formation process at the liquid carbon dioxide injection into the porous reservoir initially saturated with methane and water are presented. In the rectilinear-parallel approach the analytical solutions which describe the distributions of main parameters in the reservoir were built. On the basis of the obtained solutions, it is shown that, depending on the injection pressure of carbon dioxide, it is necessary to consider the frontal surface or the extended zone of the gas hydrate formation.

Injection of liquid carbon dioxide into a reservoir partially saturated with methane hydrate

A mathematical model is proposed to describe methane–carbon dioxide replacement in gas hydrate by injecting liquid carbon dioxide into a porous medium initially saturated with methane and its hydrate. Self-similar solutions of the axisymmetric problems are constructed that describe the distribution of the main parameters of the reservoir. It is shown that there exist solutions according to which the process can occur both with and without boiling of carbon dioxide. Diagrams of the existence of each type of solution are constructed.

Formation of hydrate in injection of liquid carbon dioxide into a reservoir saturated with methane andwater

Injection of liquid carbon dioxide into a depleted natural gas field is investigated. A mathematical model of the process which takes into account forming CO2 hydrate and methane displacement is suggested. An asymptotic solution of the problem is found in the one-dimensional approximation. It is shown that three injection regimes can exist depending on the parameters. In the case of weak injection, liquid carbon dioxide boils up with formation of carbon-dioxide gas. The intense regime is characterized by formation of CO2 hydrate or a mixture of CO2 and CH4 hydrates. Critical diagrams of the process which determine the parameter ranges of the corresponding regimes are plotted.

The theory of injection of liquid carbon dioxide in formation, saturated system “hydrate of methane–methane” in the mode of formation of the intermediate melt zone

The scheme and the corresponding theoretical model of process of methane replacement by liquid carbon dioxide at his injection in a gas hydrate layer are offered. The flat one-dimensional automodel solution corresponding to injection of carbon dioxide in semi-infinite layer through flat border is constructed. It is fixed that such solution can contain three characteristic zones in general case: the far zone, where there is a methane filtration in the porous medium which is partially saturated by methane hydrate in the absence of phase transitions; the melted zone of products of decomposition of methane hydrate (water and methane) can be formed in the intermediate zone (this zone is formed because of heating owing to injection of warm carbon dioxide); the near zone where there is a filtration of liquid carbon dioxide in the layer which is partially saturated by hydrate of carbon dioxide. The analysis of influence of parameters of layer, his initial state (temperature, pressure and hydrate saturation) and the parameters of the injected dioxide of carbon on the various modes of filtration is conducted.

Novel Extrusion Dies with Rotating Rollers for CO2-Plastic Foam Production

Abstract This paper describes a new roller die design capable of generating high pressures to allow the direct injection of liquid carbon dioxide into polymer melts and produce low density foams. The novelty of the design lies in the counter-flow action of a pair of rotating rollers separated by a gap to build up pressure. A mathematical model of the flow in the extrusion-roller die system is described and tested against experimental data with PS, LDPE and PP under a wide range of roller speeds and gaps. The study shows that this new design is feasible but more comprehensive CFD simulations and experiments are required to optimise design and operation to obtain the low-density polymer foams sought.

Post-inertisation of PWR containments by injection of liquid carbondioxide / Nachinertisierung von DWR-Containments durch Einspeisung von flüssigem Kohlendioxid

Several methods are under discussion to mitigate the consequences of the release of large amounts of hydrogen which inevitably accompanies the course of any severe accident in light water cooled power reactors. Injection of liquid carbondioxide is a well established fire fighting method and could also be used for post-inertisation. The installation of a sufficient number of catalytic recombiners to remove the released hydrogen remains as a supplementary option. The containment code RALOC has been extended to simulate the influences of the injection of liquid CO 2 through nozzles into the post-accidental containment atmosphere. The model has been validated using some experimental data obtained from flooding tests for fire fighting systems. Results of analytical simulations for a typical PWR containment indicate the applicability of post-inertisation as a convincing mitigation strategy. Now some tests, more typical for PWR containments would be desirable to confirm the post-accident inertisation simulations.