Super High Pressure Research Articles

Enhanced mechanical properties of LPSOp/Mg composites using super high pressure treatment

The super high pressure (SHP) technique was employed to fabricate the magnesium matrix composites (MMCs) reinforced with long-period stacking order structure powder (LPSOp) by cubic-anvil large-volume press with six rams. The LPSOp was optimized through high energy ball milling (HEBM) with a chemical composition of Mg85Zn6Y9 (at%). The microstructure and mechanical properties of LPSOp/Mg composite was characterized by X-ray diffraction (XRD), scanning electron microscopy/transmission electron microscopy (SEM/EDS), transmission electron microscopy (TEM), microhardness and compressive tests. The microhardness of LPSOp exhibits a notable increase after HEBM, and the thermal stability of LPSOp is affirmed through elevated annealing. The SHPed LPSOp/Mg consists of Mg and LPSO phase. Upon annealing at 400 °C for 1 h, the LPSO phase precipitates from solid solution of Mg and W phase is also identified. The strength of composites by SHP treatment and subsequently annealing is significantly improved compared with the pure Mg without LPSOp, which demonstrates the maximum compression yield strength (CYS) of 250 MPa and ultimate compression strength (UCS) of 375 MPa with satisfactory ductility. The enhanced mechanical properties are attributed to the synergistic reinforcement effects of the dispersed and 3D skeletal structure of LPSOp with excellent interfacial bonding, the coexistence of nano-scale LPSO and W phase and partial solid solution strengthening.

An ultra-lightweight and hydrophobic piezoresistive foam with super-wide strain and pressure detection range

Achieving a piezoresistive sensor with extensive strain and pressure response range for subtle and large motion detection remains a formidable challenge. Furthermore, an advanced parameter (waterproof capability), which is critical for wearable sensors, has received insufficient attention in current research. Herein, macroscopically segregated polyolefin elastomer (POE)/carbon nanostructures (CNS) foams with a super-low density and superior waterproof were fabricated via supercritical CO2 foaming, revealing a facile and eco-friendly process. Compared to piezoresistive foams with randomly distributed structure, POE/CNS foam sensors with macroscopically segregated structure displayed an ultra-low density (∼0.1 g/cm3), and apparently improved piezoresistive behavior. Additionally, the segregated POE/CNS foams exhibited a remarkably lower percolation threshold of around 0.011 vol%, enabling stable piezoresistive capability even with an ultra-low CNS content of approximately 0.0043 vol%. Therefore, the prepared POE/CNS foam sensors (FCNS0.1 and FCNS0.5) demonstrated an exceptional strain and pressure response range (0.5%–90% compression strain and approximately 0.5–3700 kPa), and the foam sensor (FCNS0.5) displayed a broad linear strain response range from 10% to 90% compression strain. Moreover, the segregated POE/CNS foams exhibited good hydrophobicity, enabling the piezoresistive foam (FCNS0.5) to maintain its sensing ability underwater. These outstanding piezoresistive performances enabled the foam sensors to monitor diverse human motions including subtle and superhigh pressure. Consequently, piezoresistive foams with exceptional performance and versatile applications lay the foundation for the development of the next generation of foam sensors.

Procedural Safety and Efficacy of Super-High Pressure OPN Balloon in Patients With Moderate to Severely Calcified Coronary Artery Disease – A Single-Centre, Real-World Experience From India

Procedural Safety and Efficacy of Super-High Pressure OPN Balloon in Patients With Moderate to Severely Calcified Coronary Artery Disease – A Single-Centre, Real-World Experience From India

Treatment of Calcified Lesions Using a Dedicated Super-High Pressure Balloon: Multicenter Optical Coherence Tomography Registry

BackgroundCalcified lesions often lead to difficulty achieving optimal stent expansion. OPN non-compliant (NC) is a twin layer balloon with high rated burst pressure that may modify calcium effectively. MethodsRetrospective, multicenter registry in patients undergoing optical coherence tomography (OCT) guided intervention with OPN NC. Superficial calcification with > 180o arc and > 0.5 mm thickness, and/or nodular calcification with > 90o arc were included. OCT was performed in all cases before and after OPN NC, and after intervention. Primary efficacy endpoints were frequency of expansion (EXP) ≥80 % of the mean reference lumen area and mean final EXP by OCT, and secondary endpoints were calcium fractures (CF), and EXP ≥90 %. Results50 cases were included; 25 (50 %) superficial, and 25 (50 %) nodular. Calcium score of 4 in 42 (84 %) cases and 3 in 8 (16 %). OPN NC was used alone, or after other devices if further modification was needed, NC in 27 (54 %), cutting in 29 (58 %), scoring in 1 (2 %), IVL in 2 (4 %); or if non-crossable lesion, rotablation in 5 (10 %) cases. EXP ≥80 % was achieved in 40 (80 %) cases with mean final EXP post intervention of 85.7 % ± 8.9. CF were documented in 49 (98 %) cases; multiple in 37 (74 %). There were 1 flow limiting dissection requiring stent deployment and 3 non-cardiovascular related deaths in 6 months follow-up. No records of perforation, no-reflow or other major adverse events. ConclusionAmong patients with heavy calcified lesions undergoing OCT guided intervention with OPN NC, acceptable expansion was achieved in most cases without procedure related complications.

CRT-100.3 Procedural Safety and Efficacy of Super-High Pressure OPN Balloon in Patients With Moderate to Severely Calcified Coronary Artery Disease – A Single-Centre, Real-World Experience From India

CRT-100.3 Procedural Safety and Efficacy of Super-High Pressure OPN Balloon in Patients With Moderate to Severely Calcified Coronary Artery Disease – A Single-Centre, Real-World Experience From India

Issues in deep peak regulation for circulating fluidized bed combustion: Variation of NOx emissions with boiler load

In order to improve the consumption of renewable energies, certain amounts of circulating fluidized bed (CFB) boiler units should assume the task of deep peak regulation. However, the effect of CFB boiler load on pollutant emissions such as NOx still needs to be clarified. In this paper, the NOx emission characteristics of two industrial-scale CFB boilers within a wide load range (35%–100%) were further analyzed by using a comprehensive one-dimensional, two-phase CFB mathematical model. Simulation results reveal that, when the load ratio decreases, the NOx emission decreases first and then increases. The non-monotonic variation trend is also confirmed by the operational data collected from the SC-350 boiler. However, for different boilers, the load ratio corresponding to the turning point of NOx emission may be different, e.g., for the 135 MWe super high steam pressure boiler, it is about 40%, while for the 350 MWe supercritical boiler is 50%. On the one hand, the decrease in boiler load leads to a decline in the furnace temperature, which contributes to reducing NOx emission due to the decrease of volatile yields, the lower conversion rate of Vol-N to NOx, and the enhancement of the overall NO reduction on chars. On the other hand, at low loads, the excess air coefficient is generally set to high values, and air staging is weakened, resulting in adverse effects on the NOx emission control. In addition, when the CFB boiler operates at low loads, the solid circulation loop performance usually worsens, and the heat loss caused by incomplete combustion may increase. This study points out that high NOx emission is an unavoidable issue in the process of deep peak regulation for CFB boilers.

Development of biomass-fired circulating fluidized bed boiler with high steam parameters based on theoretical analysis and industrial practices

Further improvement of steam parameters is essential to developing biomass-fired circulating fluidized bed (CFB) boiler technology, which necessitates solving severe slagging, fouling, agglomeration, and corrosion problems caused by the high content of alkali metals and chlorine in biomass fuels. Studies indicate that by arranging the high-temperature heating surfaces inside the furnace, the slagging and corrosion of the surface can be effectively lightened through the continuous wash and cleaning by solid circulating ash. Meanwhile, the ash fouling on the convective heating surface can be mitigated by applying in-line tube bundles with large intercept, small tube diameter, and parallel flow design. In addition, the significant improvement of circulating loop performance can not only alleviate the bed agglomeration but also help increase the boiler efficiency, decrease slagging on the heating surface, and reduce the NOx emission. Series biomass-fired CFB boilers with high steam parameters have been successfully established based on these technical routes, including one 125 MW super-high pressure boiler with the largest capacity and the highest steam parameters in Asia. Lone-term operational data from four commercial CFB boilers show that they can operate stably within a wide range of load ratios, from 30% to 105%, and continuous operation time can last more than half a year. Moreover, the boiler efficiency can reach up to 90%–93.5%, and the NOx and SO2 emissions can be stably controlled lower than the ultra-low emission standard in China. The variation of some operation parameters with boiler load was also discussed in this work.

A study on the oyster shucking machine using super-high pressure

A study on the oyster shucking machine using super-high pressure

Recrystallization Characteristics of Catalytic Alloy and Graphite in Diamond Synthesis

We first consider the recrystallization characteristics of catalysis alloy and graphite in the process of diamond synthesis under the condition of super high pressure and high temperature in catalysis method. In the process of diamond synthesis catalysis metal is plastically deformed by increase of pressure and then recrystallized as increasing the temperature. As catalysis metal is recrystallized, the shape of graphite particle is in spherical shape in the region contacting with the catalyst but in any shape in the opposite region. In addition, we calculate the electron charge density distribution and cohesive energies of cementite structure using the first principle method to investigate the reciprocal interaction between transient metal elements and carbon atoms in high-temperature catalyst synthesis. After determination of lattice constant parameters, we obtain the cohesive energy by subtracting the total energy of the crystal from the summation of total energies of atoms composing the crystal and dividing it by the number of atoms. Therefore, the effect of the catalyst on the diamond synthesis is to be analyzed theoretically.

Direct extraction of lipids from wet microalgae slurries by super-high hydrostatic pressure

Microalgae are undergoing intense study as feedstock to produce biodiesel. However, due to the relatively low price of biodiesel, microalgae have recently been considered a novel source of food and functional products because they contain valuable natural products. Lipid extraction from wet microalgae slurries is considered an energy-saving extraction technique and often includes the use of liquid CO2, switchable solvent, organic solvent, dimethyl ether, and other pre-treatment methods. These methods led to either low extraction efficiencies additional treatment of the residue, or both. Therefore, super-high hydrostatic pressure (100–1000 MPa) is a processing technology mainly applied in the food industry for non-thermal sterilization that could offer several benefits: 1) a super-high pressure can disrupt cells and increase extraction yield; 2) non-thermal treatment will guarantee the extraction of biofunctional products without limited destruction; and 3) a super-high pressure saves energy costs for sterilization and denaturation of the residue, which could be used as a commercial edible protein or animal feed. However, there are no previous reports about lipid extraction by super-high hydrostatic pressure from wet microalgae slurries or regarding considerable challenges. In this study, we investigated two types of extraction from wet microalgae slurries by super-high hydrostatic pressure: one-step extraction and two-step extraction. We also compared the super-high hydrostatic pressure technique with high-pressure homogenization, ultrasonication and microwave extraction by evaluating cell disruption and lipid extraction yields. The highest cell disruption of 92.8 ± 2.7% and lipid extraction yield of 11.4 ± 0.4% were obtained when super-high hydrostatic pressure (SHHP) was applied in the one-step extraction process. In the two-step extraction process, the highest cell disruption of 87.8 ± 2.3% and lipid extraction yield of 10.1 ± 0.7% were obtained by SHHP treatment which was higher than those achieved by the other three treatments with the same wet microalgae slurry. Thus, SHHP can achieve high cell disruption and lipid extraction yields from wet microalgae slurries through the one-step extraction method.

Ethylene Yield from a Large Scale Naphtha Pyrolysis Cracking Utilizing Response Surface Methodology

Statistical software is a robust application that has proven reliable worldwide. However, it is not normally used in the actual large scale olefin plant as it relies on the simulation software by Olefin Licensor should any issue rises. The study was conducted in a newly commissioned large scale olefin plant to see the impact of various operating variables on the ethylene yield from Short Residence Time (SRT) VII Furnace. The analysis was conducted utilizing statistical analysis, Response Surface Methodology (RSM) in Minitab Software Version 18 to develop a reliable statistical model with a 95% confidence level. The historical data was taken from the Process Information Management System (PIMS) Software, PI Process Book Version 2015, and underwent both residuals and outliers removal prior to RSM analysis. 10 variables were shortlisted from the initial 15 identified variables in the studied SRT VII via Regression analysis due to RSM limitation to conduct the larger analysis in Minitab Software Version 18. The Response Optimizer tool showed that the ethylene yield from naphtha pyrolysis cracking in the studied plant could be maximized at 34.1% with control setting at 600.39 kg/ hr of Integral Burner Flow, 6.81% of Arch O2, 113.42 Barg of Steam Drum Pressure, 496.96°C of Super High Pressure (SHP) Temperature, 109.11 t/hr of SHP Boiler Feed Water (BFW) Flow, 92.78 t/hr of SHP Flow, 63.50 t/hr of Naphtha Feed Flow, and -13.38 mmHg of Draft Pressure.

Gas pressure measurement using micro-corona-discharging effect in surface acoustic wave resonators

This paper reports a gas pressure sensor using surface acoustic wave resonator (SAWR) based on both the field-induced electron emission and the micro-corona-discharging (MCD) phenomena. With the micron-scale finger-gap of electrodes covered with SiO2 passivation layer, the enhanced field-effect emission (FEE) at electrodes result in the micro-corona-discharging and thus the change in the dynamic resistance of SAWR. A high Q-factor SAWR was fabricated on ST-cut quartz substrate using microelectronics processing technology, and the gas-pressure-dependent return-loss was tested, and the MCD theory and the equivalent circuit model of SAWR were used to analyze the test results. Under argon pressure range from 0 to 601 kPa, the dynamic resistance of the SAWR varies from 24.569 to 41.589 Ω at 25 °C. The resistance rate reaches 69.3%, which is far higher than that of traditional piezoresistive pressure sensors. At the same time, the oxygen pressure was also tested by the SAWR as a comparison. The SAW-based gas pressure sensors have the potential for measurement of the super-high pressure.

Anomalies in the dynamics of a metallic glass-forming liquid under super-high pressure

The atomic dynamics of a Zr50Cu50 metallic glass-forming liquid has been investigated in isothermal compression by using molecular dynamics simulations. It is found that the mean square displacement (MSD) for Zr is unexpectedly larger than that for Cu under super-high pressures. This interesting result challenges our understanding that the Cu atoms are always faster than Zr atoms in normal liquids, suggesting that the atomic dynamics for Zr becomes extraordinary under super-high pressure. We found that the shorter-bonded Zr atoms can be formed under-super high pressure because of the remarkable softness of Zr-Zr bonding ways. Further studies suggest that this special local structure is responsible for the unexpected atomic dynamics of Zr. These results shed light on the understanding of the inimitable dynamics in Zr-based metallic glass-forming liquids under super-high pressure.

Fuzzy Control Strategy of Relief System for Extra-High Pressure Test Equipment

To realize accurate super-high hydraulic pressure curve control of relief system for isostatic pressure test equipment, a method of designing fuzzy control strategy, including theoretical analysis, modeling, designing fuzzy controller, optimizing fuzzy rules and simulation, was introduced. Precise mathematic model based on theoretical inferring and experimental computing was developed and used for studying control strategy and optimizing control rules. High-accurate controller based on fuzzy control theory was studied and fuzzy controller rules were optimized. A simulation platform composed of input variable, controller, mathematic model and output variable was obtained and successfully used for studying the control of relief process. Computer simulation and physical test experiments indict that the control precision of relief system reaches ±0.5Mpa during the pressure domain above 30MPa, the fuzzy controller strategy meets the high-accurate pressure control requirements of super-high pressure test equipment.

Ethylene Yield from Pyrolysis Cracking in Olefin Plant Utilizing Regression Analysis

Ethylene yield is significant in showing the performance of the steam cracker furnace in the olefin plant. This study was conducted in the actual large-scale olefin plant to see the impact of various variables towards the ethylene yield. The analysis was conducted utilizing Regression Analysis in Minitab Software Version 18 to develop a reliable ethylene yield model. The model concluded that ethylene yield in the studied plant was contributed by the factor of -0.000901, 0.02649, -0.282, 0.16, -0.0834, 0.1268, and 0.0057 of Hearth Burner Flow, Integral Burner Flow, Steam Drum Pressure, Super High-Pressure Steam (SHP) Boiler Feed Water Flow, SHP Flow, Naphtha Feed Flow, and Stack NOx Emission respectively. The Response Optimizer tool also showed that the ethylene yield from naphtha liquid feed utilizing pyrolysis cracking can be maximized at 32.55% with control setting at 9,476.41 kg/hr of Hearth Burner Flow, 608.56 kg/hr of Integral Burner Flow, 112.93 Barg of Steam Drum Pressure, 109.11 t/hr of SHP Boiler Feed Water Flow, 86.42 t/hr of SHP Flow, 63.49 t/hr of Naphtha Feed Flow and 126.23 mg/m3 of Stack NOx Emission.

The Influence of Nozzle Parameters on the Atomization Performance of Non-normal Fuel based on the Super-high Pressure Common Rail System

The uniformity of the fuel and air mixture in the cylinder of diesel engine directly affects the smooth running of the combustion process. In order to improve the atomization effect of the fuel in the cylinder, the super-high injection pressure exceeding 180MPa was used. The changing relationship between the physical properties of the non-normal fuel and the pressure under the influence of the super-high injection pressure was derived. The three-dimension combustion model of TBD620 diesel engine is constructed on the FIRE software platform. A numerical simulation of the two injectors’ fuel injection process under different load conditions has been done in the research work. The fuel spray characteristics has been simulated. The results show that the special fuel injector has a good performance under low loading conditions, but the standard fuel injector has better performance for oil and gas fully mixed under high loading conditions.

Superhigh-pressure fragments of metal nitride/carbide ceramic powders and their behavior under high-pressure and high-temperature sintering

Metal nitride and/or carbide ceramic powders, TiC, TiN, TiCN, and TaC ceramic powders, were selected as initial materials for simulation experiments of superhigh-pressure extrusion and high-pressure and high-temperature sintering, whose fragmentation law and sintering behavior were evaluated by using SEM, laser particle size analyzer, and XRD. Meanwhile, the compressibility and agglomeration of the powders were calculated and analyzed. Results show that intragranular cracks, fragmentation, and particle breakage take place in the ceramic powder particles, and crushed fine particles adhere to coarse particles and form larger particle aggregates, or filling the particle voids during sintering. The diffraction peaks shift to higher angles with a certain FWHM broadening and decreased peak intensity. The existence of intragranular cracks and honeycomb groove damage has a negative impact on the performance of the sintered body. In addition, the ceramic powders show high compressibility and strong agglomeration under the action of superhigh pressure.

First principles study of post-boron carbide phases with icosahedra broken**Project supported by the National Natural Science Foundation of China (Grant Nos. 51871114 and 12064013), the Natural Science Foundation of Jiangxi Province, China (Grant No. 20202BAB214010), the Research Foundation of the Education Department of Jiangxi Province, China (Grant Nos. GJJ180433 and GJJ180477), the Open Funds of the State Key Laboratory of

Boron carbide (B4C) is a rhombic structure composed of icosahedra and atomic chains, which has an important application in armored materials. The application of B4C under super high pressure without failure is a hot spot of research. Previous studies have unmasked the essential cause of B4C failure, i.e., its structure will change subjected to impact, especially under the non-hydrostatic pressure and shear stress. However, the change of structure has not been clearly understood nor accurately determined. Here in this paper, we propose several B4C polymorphs including B4C high pressure phases with non-icosahedra, which are denoted as post-B4C and their structures are formed due to icosahedra broken and may be obtained through high pressure and high temperature (HPHT). The research of their physical properties indicates that these B4C polymorphs have outstanding mechanical and electrical properties. For instance, aP10, mC10, mP20, and oP10-B4C are conductive superhard materials. We hope that our research will enrich the cognition of high pressure structural deformation of B4C and broaden the application scope of B4C.

A novel super high back pressure cascade heating scheme with multiple large-scale turbine units

The recovery of waste heat from power generation by the utilization of energy cascade for district heating has become an important method to improve the energy saving of combined heat and power (CHP) plants. In this paper, a novel super high back pressure (SHBP) cascade heating scheme is proposed to recover waste heat further and tap the energy saving potential of multi-unit combined heating system. On this basis, the regulation progress under full heating conditions is simulated. It’s concluded that the regulation progress can be divide into 4 stages, and the flow of extraction steam or the back pressure of turbines is adjusted to satisfy the varying heating demand. Furthermore, the detailed thermodynamic analysis of the novel cascade heating scheme is performed. The results indicate that, in the design condition, the heating process exergy efficiency of the SHBP scheme is improved by 10.4%, leading to an addition of 136.6 MW in generating power and a decline of 30.1% in the heating consumption rate. During the whole heating period, exhaust steam heat load ratio of the SHBP system reaches to 92.5%, which brings about the average heating consumption rate only 5.30 kg/GJ, and 72 thousand tons standard coal saved in total.

Fracturing technologies of deep shale gas horizontal wells in the Weirong Block, southern Sichuan Basin

Stimulation of hydraulic fracturing of horizontal shale gas wells in Weirong Block has always been facing many difficulties due to many factors such as complicated geological conditions, small differences between the horizontal principal stress and the vertical principal stress, high working pump pressures, and low sensitive sand ratios. In view of this, by combing the geological structure, engineering geological characteristics and the difficulties of fracturing of deep shale gas wells in Weirong Block, learning from the general idea of volumetric fracturing for shale gas reservoirs at home and abroad, we determined the main ideas and technical countermeasures for fracturing in the area and applied them to the subsequent fracturing practices of shale gas wells. And the following achievements were obtained. First, the conventional fracturing technology applied to the shale gas wells in Weirong Block resulted in low fracture complexity, small stimulated reservoir volume (SRV), difficulties in guaranteeing the effectiveness of perforation clusters, low strength of proppant adding, difficulties in obtaining higher conductivity, poor stable production capacity after stimulation, and difficulties in meeting the need of well fracturing with casing deformation. Second, in view of the difficulties of fracturing stimulation in deep shale gas wells of Weirong Block, super high pressure, huge displacement, large fluid volume, temporary plugging and diverting in fracturing, and variable displacement technology can effectively increase SRV and the complexity of fractures in distant wells. The effectiveness of multi-cluster perforation can be guaranteed by comprehensive utilization of multi-cluster perforation optimization technology, big displacement technology and temporary plugging and diverting & fracturing technology at slots. The continuous proppant-adding technology with huge displacement, high viscosity, low sand ratio, low density and small particle size can improve sand adding strength and fracture conductivity. Besides, the stimulation technology for casing deformed wells using coiled tubing fast processing + small diameter bridge plug and separate pumping technology of perforating gun have been formed. Third, after the above fracturing technologies have been applied in five shale gas horizontal wells in Weirong Block, the average absolute open flow (QAOF) reached 26.11 × 104 m3/d, indicating a good stimulation effect. In conclusion, this paper can provide meaningful reference for the development of deep shale gas wells of the similar type.