High-pressure Apparatus Research Articles

Experimental Study on CO2 Huff and Puff in the Daqing Fuyu Tight Oil Reservoir with Online NMR

Tight oil is a typical unconventional resource, and enhancing its recovery rate remains a challenge in current development efforts. In this study targeting the Daqing Fuyu tight oil reservoir, we combine a high-temperature and high-pressure long core physical simulation apparatus and a high-temperature and high-pressure online Nuclear Magnetic Resonance (NMR) testing system to conduct indoor simulation experiments on CO2 huff and puff in long cores. The results indicate that in the process, it is primarily the oil from micro-pores that is initially mobilized, but further along mobilization of fluids from a portion of sub-micro-pores and nanopores is enhanced, with an efficiency ranging from 25-33%. It was also found that there exist optimal conditions for huff and puff pressure, soaking time, and huff and puff cycles. Additionally, excessive extraction of light components by CO2 can prove disadvantageous for further improvement in huff and puff efficiency. This study can provide insight into the mechanisms of and data support for the development of CO2 huff and puff strategies in tight oil reservoirs, thereby contributing to the formulation of effective development plans.

The influence of pure compounds’ parameters on the phase behaviour of carbon dioxide + 1-hexanol binary system

New vapour–liquid–liquid and vapour–liquid equilibrium data to complement the existing ones are measured at six temperatures (308.15 K to 383.15 K) and at pressures up to 182.9 K using an analytic-static method with phases sampling via special valves (“AnTVisVarCap”, as defined by Prof. Ralf Dohrn and co-workers) for the carbon dioxide (1) + 1-hexanol (2) binary system. Four out of the six isotherm reported here are measured for the first time. The main component of the high-pressure setup is a 60 cm3 visual cell.The new isotherms are compared with the available literature which is also reviewed and analysed. It should be noted that among the data already published, only one other research group reported the compositions of both phases at equilibrium, as we did previously by using another experimental method. The new and literature data were modelled with Peng-Robinson (PR) and Soave-Redlich-Kwong (SRK) equations of state based on a semi-predictive procedure to reproduce as well as possible the minimum and the maximum of the critical curve(s) using one set of binary interaction parameters. The influence of critical data and acentric factors of pure components on the phase behaviour of their binary system is discussed. Although the values of the critical pressures and acentric factors of pure substances are not very different in the database we used, the models predict type III or IV phase behaviour with the same set of binary interaction parameters. This sensitivity, which was not observed for other systems we studied, could be explained by the alcohol structure and high asymmetry of the system. Therefore, we analysed in more depth the influence of the critical temperatures and pressures, as well as the acentric factors of carbon dioxide and 1-hexanol and exemplified for one temperature located above the system UCEP's temperature.

Ultrafast spectroscopy of coherent phonons across the pressure driven insulator to metal phase transition in V2O3

Nowadays, materials science is moving towards the understanding and control of materials in nonequilibrium states by making use of perturbative techniques to investigate their dynamical responses. From this perspective, the use of ultrashort light pulses seems to be a relevant approach as it can selectively address different degrees of freedom in solid-state systems and more particularly electrons. Such a method can help to decipher the physical phenomena arising from electronic correlations and complements a more conventional methodology where the phase diagrams of materials are investigated at thermodynamical equilibrium. Here, we combine femtosecond optical spectroscopy and a high-pressure setup to monitor the ultrafast out-of-equilibrium photo response of a V2O3 thin film across the pressure driven insulator-to-metal transition. The experimental results demonstrate the possibility to use the spectroscopy of coherent phonons as a thermodynamical phase marker in V2O3 thin films. In addition, the frequency behavior of the ultrafast coherent phonon mode (A1g character) seems to reflect the manifestation of a strong coupling between the lattice and electronic degrees of freedom near first-order transition lines with a pronounced drop in frequency around the critical pressure. Published by the American Physical Society 2024

Vapor-liquid equilibria for the CO2 + trimethoxymethylsilane and CO2 + triethoxymethylsilane systems under high-pressure conditions

New binary isotherms are crucial for designing chemical separation processes within supercritical carbon dioxide (CO2) + trialkoxysilane systems. Vapor-liquid equilibria (VLE) were investigated for two-component systems, trimethoxymethylsilane + CO2 and triethoxymethylsilane + CO2, at five temperatures (313.2, 333.2, 353.2, 373.2, and 393.2 K) and pressures up to 14.07 MPa using a synthetic high-pressure phase equilibria apparatus. The pressure-temperature (P-T) plot indicates that the critical mixture curve lies between the critical points of CO2 and the trialkoxysilane compounds. The solubility of trimethoxymethylsilane and triethoxymethylsilane in CO2 increased with increasing temperature at constant pressure, following a type-I phase behavior characteristic. The experimentally observed VLE values of the CO2 + trialkoxysilane systems were correlated using the Peng-Robinson equation of state with binary parameters (kij and ηij) in the conventional mixing rule. The model accuracy was validated by calculating the average relative deviation percentage for the pressure of the binary systems, resulting in values of 4.98% for the trimethoxymethylsilane + CO2 system and 3.64% for the triethoxymethylsilane + CO2 system. The estimated variables fell within reasonable limits and showed no significant differences between the predicted and observed VLE data for both systems.

Comparison of upward and downward flow in high-pressure bulk CO2 gas adsorption on NaY zeolite fixed bed

Adsorption is an appealing technology for the removing of CO2 from natural gas because it can handle high CO2 concentrations at high pressures. The determination of mono-component breakthrough curves provides heat and mass transfer parameters to assess separation effectiveness that can be used for simulation of swing adsorption separation processes (PSA, TSA etc.). However, in lab-scale fixed-bed adsorption, it may be challenging to perform this assessment due to low flow conditions that are usually employed, affecting the flow regimedepending on the operation conditions. In this sense, this work aimed to evaluate the effect of flow regime configurations and difference in gases densities by means of residence time distribution (RTD) analysis in the PSA of CO2 in a NaY zeolite fixed bed , in order to to collect information that satisfy pipeline specifications in industrial applications. A high-pressure lab-scale apparatus was used with NaY particles of 0.7250 mm mean diameter, a 10.5 cm bed height , and a tubular column of 2.0 cm internal diameter. The upward and downward flows were conducted under 528.82 ± 4.59 NmL min−1 inlet mass flow rate, 51 bar, and 30 °C. The RTD analysis was performed to verify the flow regime, and mass transfer zone (MTZ) length was estimated. It was observed that downward flow conditions promoted higher concentration spread than upward flow. RTD analysis showed that downward flow is dominated by laminar convection while the upward flow is dominated by dispersion. MTZ length increased from 0.64 cm in upward flow to 5.81 cm in downward flow. Therefore, assessing CO2 flow conditions and, additionally, the difference in gases densities, are important steps that should be taken when dealing with fluid adsorption under high pressure because different densities between fluid components severely changed and affected flow regime and, consequently, separation effectiveness.

Impregnation of Graphite with Aluminum under High Pressure

To impregnate graphite of the GMZ brand with liquid aluminum alloy D16, a high-pressure method and apparatus previously used for impregnating carbon frames with liquid coal pitch in the isostatic technology for the production of carbon-carbon composite materials were used. The graphite blank and the amount of aluminum alloy calculated from the initial porosity of graphite were placed in a thin-walled container, degassed in a vacuum furnace, after which the container with the contents was sealed. Thermobaric treatment was carried out at a temperature of 750°C and pressure of 100 and 200 MPa. After finishing the treatment, the density and porosity of the obtained metallographic composites, as well as their compressive strength, were determined. As a result of these thermobaric treatments, the density and compressive strength of the obtained composites increased significantly, and the porosity decreased markedly.

Decomposition behavior of GaN under solid and ambient N2 pressure

We investigated the decomposition behavior of GaN crystals under high N2 and solid pressures using a belt-type high-pressure apparatus. The decomposition curve of GaN under solid pressure showed a considerably moderate increase compared to that under a N2 pressure. Such difference was attributed to the N2 dissolution in the Ga melt, where a high N2 pressure creates a supersaturated GaN state, which effectively prevent its decomposition. Conversely, under a solid pressure, the increase in the GaN decomposition temperature followed a common change in enthalpy, which is consistent with its typical thermodynamic behavior. The decomposition behavior of GaN under a solid pressure demonstrated its successful high-temperature annealing using a belt-type high-pressure apparatus. Therefore, this study provides valuable insights into the thermodynamic stability of GaN under different pressures, which is critical for optimizing high-performance GaN-based devices.

Experimental evaluation of the influence of the diffuser inlet to nozzle exit cross sectional area ratio on pressure oscillation in a high-altitude test facility

The ratio of diffuser inlet to nozzle exit area (Ad/Ae) is one of the most important parameters in designing and evaluating the performance of a high-altitude test facility (HATF). Typically, at motor pressures near start or operating pressure of the diffuser, the vacuum chamber pressure oscillates at a high Ad/Ae, which may be dangerous for the HATF. In the present study, the effect of the Ad/Ae on the starting and breakdown performance of a second throat exhaust diffuser (STED) has been investigated experimentally using a HATF supplied by high-pressure cold air apparatus. Upon examining the overall performance of the diffuser, it is observed that with an increase in Ad/Ae, the oblique sealing shock wave at the diffuser inlet undergoes significant changes in location and strength. This leads to a further reduction of the flow total pressure and a stronger separation of the flow along the diffuser. Consequently, flow instability arises during starting or breakdown phases near the STED starting or operating pressure. By frequency analysis, it is observed that as Ad/Ae increases, the number of oscillatory modes of the vacuum chamber pressure increases and the dominant frequency of the oscillations in these transient situations becomes larger. Additionally, there is a significant decrease in nozzle pressure related to the onset of pressure oscillations. Furthermore, with an increase in Ad/Ae from 1.27 to 7.81, the minimum starting pressure and breakdown pressure of STED increase by 20.33% and 28.47%, respectively. Also, the hysteresis range in performance of STED vanishes at high Ad/Ae values.

Equilibrium curves and modeling of binary systems for the carbon di-oxide + benzyl acetoacetate and carbon di-oxide + benzyl acetate mixtures under high pressure

The solution phase behavior of the binary systems of supercritical carbon di-oxide (SU-CO2) + benzyl acetoacetate and SU-CO2 + benzyl acetate was investigated in a synthetic high-pressure apparatus at five temperatures from 313.2 to 393.2 K and pressure up to 33.53 MPa for the industrial benefit of food, pharmaceutical and cosmetics application. The solubility of benzyl acetoacetate and benzyl acetate in the SU-CO2 + benzyl acetoacetate and SU-CO2 + benzyl acetate systems were increased with increasing temperature at constant pressure, respectively. Both system isotherms were exhibited in the simple Type-I category phase behavior. Besides, the Peng-Robinson equation of state has been successfully applied to predict the phase behavior of the SU-CO2 + benzyl ester systems using adjustable molecular interaction parameters (kij and ηij). Neither system shows a three-phase behavior at any point of temperature and pressure. A one-fluid-phase locale was ascertained above and throughout the solubility curve whereas a two-phase locale was exhibited inside the critical curve for both binary systems. The critical mixture curve provides the fingerprint for the phase behavior study of any binary system since it is used to understand and calculate thermodynamic properties effectively. The accuracy of the studied model was tested by evaluating the percentage of root mean square deviation utilizing optimized temperature-dependent mixture parameters. Indeed, this is the first reference point for the prediction of phase transition behavior for benzyl acetoacetate and benzyl acetate in SU-CO2 and the findings make a remarkable impression on industrial applications.

ИССЛЕДОВАНИЕ ВЛИЯНИЯ СОСТАВА КОМПОЗИТОВ, СОДЕРЖАЩИХ ИМПАКТНЫЕ АЛМАЗЫ, НА ИХ ЭКСПЛУАТАЦИОННЫЕ ХАРАКТЕРИСТИКИ ПРИ ЛЕЗВИЙНОЙ ОБРАБОТКЕ ЦВЕТНЫХ МЕТАЛЛОВ

The paper presents the results of resistance tests of tool composite materials containing nanostructured impact diamonds, in comparison with composites based on synthetic superhard materials, diamond and cubic boron nitride (cBN), and ВК-8 (VK-8) (WC + 8 % Co) hard alloy, during blade processing of workpieces made of brass ЛС-59 (LS -59) (57–60 % Cu) and aluminum alloy AK-7 (Al 92–94 %, Si 6–8 %). Samples of composite materials for wear resistance studies were obtained by thermobaric sintering in a highpressure apparatus. The performance of composites was assessed by the wear of the cutter back surface, as well as by a specially developed method for studying the performance characteristics of composite superhard materials, based on determining their specific productivity. As a result of the tests, it is found that composites based on impact diamonds have the highest resistance when turning non-ferrous metal alloys. In particular, the wear resistance of a composite material containing impact diamonds with the addition of cBN exceeds the wear resistance of cutters made of composite 02 (belbor) by 1.5–3 times, and that of cutters made of hard alloy VK-8 by 8–10 times. Additions of impact diamond to hard alloy in the amount of 6.25 and 12.5 vol.% increase the relative wear resistance of the hard alloy composite compared to the original VK-8 alloy by 10–15 and 20–25 %, respectively.

Inert structural transition in 4H and 6H SiC at high pressure and temperature: a Raman spectroscopy study

We conducted Raman spectroscopy measurements of 4H-SiC and 6H-SiC up to 69 GPa and 1023 K to assess the stability and bonding of SiC at high pressure and temperature. Both optic and acoustic modes were observed at wide pressure and temperature ranges. The temperature shifts of the Raman frequencies were fitted by the equation with the Bose–Einstein distribution function, and we found that the shifts were almost insensitive to the pressure. The mode Grüneisen coefficients weakly depend on the pressure and temperature, suggesting the sluggish transition of the crystal structure, unlike the previous experiments showing the transition or decomposition of SiC at high pressure and temperature conditions. Inert transitions are confirmed by Raman measurements and annealing experiments using multiple high-pressure apparatuses. The crystallinity may be a hidden critical parameter in the experiments to determine the stable polytypes of SiC under high pressure and temperature.

A novel method for determining the resistivity of compressed superconducting materials

The measurement of resistivity in a compressed material within a diamond anvil cell presents significant challenges. The high-pressure experimental setup makes it difficult to directly measure the size changes induced by pressure in the three crystallographic directions of the sample. In this study, we introduce a novel and effective method that addresses these technical challenges. This method is anticipated to offer a valuable foundation for high-pressure investigations on quantum materials, particularly those with anisotropic layered structures.

Growth of diamond in liquid metal at 1 atm pressure.

Natural diamonds were (and are) formed (thousands of million years ago) in the upper mantle of Earth in metallic melts at temperatures of 900-1,400 °C and at pressures of 5-6 GPa (refs. 1,2). Diamond is thermodynamically stable under high-pressure and high-temperature conditions as per the phase diagram of carbon3. Scientists at General Electric invented and used a high-pressure and high-temperature apparatus in 1955 to synthesize diamonds by using molten iron sulfide at about 7 GPa and 1,600 °C (refs. 4-6). There is an existing model that diamond can be grown using liquid metals only at both high pressure and high temperature7. Here we describe the growth of diamond crystals and polycrystalline diamond films with no seed particles using liquid metal but at 1 atm pressure and at 1,025 °C, breaking this pattern. Diamond grew in the subsurface of liquid metal composed of gallium, iron, nickel and silicon, by catalytic activation of methane and diffusion of carbon atoms into and within the subsurface regions. We found that the supersaturation of carbon in the liquid metal subsurface leads to the nucleation and growth of diamonds, with Si playing an important part in stabilizing tetravalently bonded carbon clusters that play a part in nucleation. Growth of (metastable) diamond in liquid metal at moderate temperature and 1 atm pressure opens many possibilities for further basic science studies and for the scaling of this type of growth.

Properties of boron-doped HPHT diamond single crystals grown in a Fe-Ti-B-C system

Boron-doped diamond (BDD) single crystals were synthesized using a large-volume cubic high-pressure apparatus (SPD-6 × 1200) in the Fe-Ti-B-C system under conditions of 6.0 GPa and temperatures ranging from 1410 to 1435 °C. Scanning electron microscope (SEM) images revealed linear textures, cracks, and dendritic growth texture on the crystal surface. The Raman spectrum exhibited additional bands at approximately 480, and 1220 cm−1, indicating high levels of boron doping. X-ray photoelectron spectroscopy (XPS) measurements confirmed the presence of boron on the crystal surface, bonded as BC and BO. By utilizing the Hall effect, the highest recorded carrier concentration in the crystal was determined to be 1.17 × 1019 cm−3, a relatively high level for diamond single crystals synthesized via the high pressure and high temperature (HPHT) method. Moreover, thermogravimetric analysis (TG) measurements verified that boron doping enhanced the thermal stability of the diamond.

Formation behaviors of gas hydrates in water-in-oil emulsions with the coexistence of asphaltenes and resins

Hydrate formation is one of the major flow assurance issues for the subsea multiphase pipelines. The effects of the interaction between heavy fractions of crude oil components on hydrate behaviors are still not well understood. In this study, the effects of resins on hydrate formation behaviors in asphaltene-containing emulsions were investigated using a high-pressure reactor apparatus. The results indicated that both resins and asphaltenes inhibited hydrate nucleation and increased the induction time. Furthermore, considerable synergistic effects of asphaltenes and resins on the hydrate formation behaviors were discovered in the water-in-oil emulsions, depending on the aggregation state of asphaltenes. The addition of resins was observed to disperse the asphaltene aggregates significantly and enhance the inhibitory effect of asphaltenes on hydrate nucleation. Additionally, the calculated results of gas consumption showed that the presence of resins can decrease the growth rate of hydrates in the asphaltene-containing emulsions. A potential mechanism was presented to illustrate how resins affect hydrate formation in an emulsion with varying asphaltene aggregation states. These findings offer a better knowledge of the synergistic effects between the heavy components of resins and asphaltenes and have potential application in the hydrate management of crude oil pipelines.

Https://vestnik.mrsu.ru/index.php/en/articles2-en/123-24-1/1114-10-15507-0236-2910-034-202401-5

Introduction. The article describes the process of considering the geometric parameters of water jet depending on a water jet operation mode and nozzle type. Within the framework of the study of hydraulic soil treatment in the under-tree zones, it became necessary to study the water jet parameters when using different types of nozzles. There was need to determine the geometric parameters of water flow for calculating the cross-sectional area and determining the structural features of the water jet formation. These characteristics are important for a complete description, subsequent study and calculation of water jet action during hydraulic soil treatment; they also allow studying the real shape and structure of the water jet when using different types of nozzles. Aim of the study. The study is aimed at determining the geometric parameters of the water jet for different nozzles including turbo cutters located at different heights. Materials and Methods. To solve this problem, there was developed a test bench, on four pillars, to which the adapter of the supply line of the high-pressure apparatus with replaceable nozzles is fixed. To fix the position and shape of the water jet with a certain frequency, a Basler ace acA1920 camera was used. There was also used a high-pressure apparatus with a maximum pressure of P = 140 MPa, a maximum flow rate of Q = 360 l/h. A standard nozzle with a flat jet, a standard turbo nozzle, and a turbo nozzle of the developed design were used. The geometric parameters of the water jet section were measured from the photographs obtained. Results. From the photos obtained, it can be seen that the rotating water stream entering the turbo nozzle of its own design and the standard turbo nozzle disintegrates from rapid rotation, forming a cone, the cross-sectional area of which is a circle, and affects the soil surface. A flat jet is characterized by a rectangular cross-section. Discussion and Conclusion. According to the results of the study we can draw the following conclusions, the nozzle of the proposed design allows creating water jets of the largest area, which should provide an increase in the working width and, as a consequence, an increase in productivity and quality of soil surface treatment in mainline plantations. This study will also make it possible to analyze the structure of the jet during its operation.

Itemized determination of As, Sb, Bi, Se, and Ge in graphite sample by HG-AFS with high-temperature microwave digestion.

In this paper, we optimized a method for fast and accurate determination of five impurity elements (As, Sb, Bi, Se, and Ge) in graphite samples to overcome the shortcomings of existing methods, such as complicated equipment, cumbersome process, multiple-time preparation, separate determination, and large error in results. Graphite samples were digested with HNO3-H2SO4-HClO4-HF in a high-temperature and high-pressure microwave digestion apparatus, and the elements were extracted and determined separately by AFS (atomic fluorescence spectrometry). There is no element loss during the processing and analysis of this method. The spike recoveries (As: 90.30%-102.3%, Sb: 90.73%-110.0%, Bi: 90.00%-99.67%, Se: 93.33%-110.0%, Ge: 92.26%-104.2%) and precision (RSD%; As: 1.34%-8.96%, Sb: 2.67%-7.10%, Bi: 1.83%-4.58%, Se: 0.36%-3.25%, Ge: 4.41%-8.65%) meet the requirements of the corresponding quality specifications. The method has some advantages (such as no elemental loss, fast testing, strong element targeting, and accurate results), and thus can achieve batch determination of graphite samples. The optimized method for graphite sample and final solution preparations can be used for diverse spectrometric technologies, and that for spectrometer conditions have reference value for HG-AFS instruments.

Mid-Infrared, Optically Active Black Phosphorus Thin Films on Centimeter Scale.

Black phosphorus (BP) is a narrow bandgap (∼0.3 eV) semiconductor with a great potential for optoelectronic devices in the mid-infrared wavelength. However, it has been challenging to achieve a high-quality scalable BP thin film. Here we present the successful synthesis of optically active BP films on a centimeter scale. We utilize the pulsed laser deposition of amorphous red phosphorus, another allotrope of phosphorus, followed by a high-pressure treatment at ∼8 GPa to induce a phase conversion into BP crystals. The crystalline quality was improved through thermal annealing, resulting in the observation of photoluminescence emission at mid-infrared wavelengths. We demonstrate high-pressure conversion on a centimeter scale with a continuous film with a thickness of ∼18 nm using a flat-belt-type high-pressure apparatus. This synthesis procedure presents a promising route to obtain optical-quality BP films, enabling the exploration of integrated optoelectronic device applications such as light-emitting devices and mid-infrared cameras on a chip scale.

Direct measurement of hydrate equilibrium temperature in CO2 and CO2 rich fluids with low water content

A high-pressure experimental setup was used to obtain experimental data on the hydrate equilibrium (melting) temperature (HET) of hydrates formed from low water content CO2 and CO2 rich mixtures. A novel method was used to measure hydrate formation temperature in addition to melting temperature directly at realistic temperature/pressure conditions encountered in transport by pipelines or ship. The method can be used to evaluate the likelihood of hydrate formation in pipelines/ships transporting pure CO2 and CO2 coming from capture processes as well as from high CO2 content produced gas. The data generated from the measurement can also be used to investigate the kinetics of hydrate formation and dissociation in low water content fluids at pipeline/ship conditions. This paper details the experimental equipment, methods, test fluids and results. Experimental results are compared against predictions of the simplified cubic plus association equation of state (sCPA-EoS) coupled with the van der Waals and Platteeuw solid solution theory.

A novel rapid cooling assembly design in a high-pressure cubic press apparatus

In traditional high-pressure–temperature assembly design, priority has been given to temperature insulation and retention at high pressures. This limits the efficiency of cooling of samples at the end of experiments, with a negative impact on many studies in high-pressure Earth and planetary science. Inefficient cooling of experiments containing molten phases at high temperature leads to the formation of quench textures, which makes it impossible to quantify key compositional parameters of the original molten phase, such as their volatile contents. Here, we present a new low-cost experimental assembly for rapid cooling in a six-anvil cubic press. This assembly not only retains high heating efficiency and thermal insulation, but also enables a very high cooling rate (∼600 °C/s from 1900 °C to the glass transition temperature). Without using expensive materials or external modification of the press, the cooling rate in an assembly (∼600 °C/s) with cube lengths of 38.5 mm is about ten times faster than that in the traditional assembly (∼60 °C/s). Experiments yielding inhomogeneous quenched melt textures when the traditional assembly is used are shown to yield homogeneous silicate glass without quench textures when the rapid cooling assembly is used.