Validation of a program for supercritical power plant calculations

NASA Astrophysics Data System (ADS)

Kotowicz, Janusz; Łukowicz, Henryk; Bartela, Łukasz; Michalski, Sebastian

2011-12-01

This article describes the validation of a supercritical steam cycle. The cycle model was created with the commercial program GateCycle and validated using in-house code of the Institute of Power Engineering and Turbomachinery. The Institute's in-house code has been used extensively for industrial power plants calculations with good results. In the first step of the validation process, assumptions were made about the live steam temperature and pressure, net power, characteristic quantities for high- and low-pressure regenerative heat exchangers and pressure losses in heat exchangers. These assumptions were then used to develop a steam cycle model in Gate-Cycle and a model based on the code developed in-house at the Institute of Power Engineering and Turbomachinery. Properties, such as thermodynamic parameters at characteristic points of the steam cycle, net power values and efficiencies, heat provided to the steam cycle and heat taken from the steam cycle, were compared. The last step of the analysis was calculation of relative errors of compared values. The method used for relative error calculations is presented in the paper. The assigned relative errors are very slight, generally not exceeding 0.1%. Based on our analysis, it can be concluded that using the GateCycle software for calculations of supercritical power plants is possible.

Oxidation Behaviors of Inconel 740H in Air and Dynamic Steam

NASA Astrophysics Data System (ADS)

Lu, Jintao; Yang, Zhen; Xu, Songqian; Zhao, Haiping; Gu, Y.

2016-08-01

Inconel 740H alloy is a candidate material for 700°C advanced ultra-supercritical (A-USC) coal-fired power plants application as superheater/reheater tube. In this work, oxidation behavior of Inconel 740H alloy was studied in static air at 750°C and 850°C, and in dynamic pure steam at 750°C, respectively. The alloy was oxidized approximately following a parabolic law in three test environment. In the static air, the oxidation rate at 850°C was about 50 times of that at the 750°C. More NiCrMn spinal and TiO2 were detected after oxidation at 850°C. Cr2O3, however, was the main oxidation product at 750°C. In the pure steam, Cr2O3 was still the main oxidation product. The oxidation rate was about 2.6 times of that in static air, but the surface roughness was much smaller and edges of oxide particles were more blurred. There was no evidence of cracks or spallation in three test environments.

A fast and sensitive method for the separation of carotenoids using ultra-high performance supercritical fluid chromatography-mass spectrometry.

PubMed

Jumaah, Firas; Plaza, Merichel; Abrahamsson, Victor; Turner, Charlotta; Sandahl, Margareta

2016-08-01

In this study, a rapid and sensitive ultra-high performance supercritical fluid chromatography-mass spectrometry (UHPSFC-MS) method has been developed and partially validated for the separation of carotenoids within less than 6 min. Six columns of orthogonal selectivity were examined, and the best separation was obtained by using a 1-aminoanthracene (1-AA) column. The length of polyene chain as well as the number of hydroxyl groups in the structure of the studied carotenoids determines their differences in the physiochemical properties and thus the separation that is achieved on this column. All of the investigated carotenoids were baseline separated with resolution values greater than 1.5. The effects of gradient program, back pressure, and column temperature were studied with respect to chromatographic properties such as retention and selectivity. Electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) were compared in both positive and negative mode, using both direct infusion and hyphenated with UHPSFC. The ESI in positive mode provided the highest response. The coefficient of determination (R (2)) for all calibration curves were greater than 0.998. Limit of detection (LOD) was in the range of 2.6 and 25.2 ng/mL for α-carotene and astaxanthin, respectively, whereas limit of quantification (LOQ) was in the range of 7.8 and 58.0 ng/mL for α-carotene and astaxanthin, respectively. Repeatability and intermediate precision of the developed UHPSFC-MS method were determined and found to be RSD < 3 % and RSD < 6 %, respectively. The method was applied in order to determine carotenoids in supercritical fluid extracts of microalgae and rosehip. Graphical Abstract Ultra-high performance supercritical fluid chromatography-a rapid separation method for the analysis of carotenoids in rosehip and microalgae samples.

Primordial clays on Mars formed beneath a steam or supercritical atmosphere.

PubMed

Cannon, Kevin M; Parman, Stephen W; Mustard, John F

2017-12-06

On Mars, clay minerals are widespread in terrains that date back to the Noachian period (4.1 billion to 3.7 billion years ago). It is thought that the Martian basaltic crust reacted with liquid water during this time to form hydrated clay minerals. Here we propose, however, that a substantial proportion of these clays was formed when Mars' primary crust reacted with a dense steam or supercritical atmosphere of water and carbon dioxide that was outgassed during magma ocean cooling. We present experimental evidence that shows rapid clay formation under conditions that would have been present at the base of such an atmosphere and also deeper in the porous crust. Furthermore, we explore the fate of a primordial clay-rich layer with the help of a parameterized crustal evolution model; we find that the primordial clay is locally disrupted by impacts and buried by impact-ejected material and by erupted volcanic material, but that it survives as a mostly coherent layer at depth, with limited surface exposures. These exposures are similar to those observed in remotely sensed orbital data from Mars. Our results can explain the present distribution of many clays on Mars, and the anomalously low density of the Martian crust in comparison with expectations.

Primordial clays on Mars formed beneath a steam or supercritical atmosphere

NASA Astrophysics Data System (ADS)

Cannon, Kevin M.; Parman, Stephen W.; Mustard, John F.

2017-12-01

On Mars, clay minerals are widespread in terrains that date back to the Noachian period (4.1 billion to 3.7 billion years ago). It is thought that the Martian basaltic crust reacted with liquid water during this time to form hydrated clay minerals. Here we propose, however, that a substantial proportion of these clays was formed when Mars’ primary crust reacted with a dense steam or supercritical atmosphere of water and carbon dioxide that was outgassed during magma ocean cooling. We present experimental evidence that shows rapid clay formation under conditions that would have been present at the base of such an atmosphere and also deeper in the porous crust. Furthermore, we explore the fate of a primordial clay-rich layer with the help of a parameterized crustal evolution model; we find that the primordial clay is locally disrupted by impacts and buried by impact-ejected material and by erupted volcanic material, but that it survives as a mostly coherent layer at depth, with limited surface exposures. These exposures are similar to those observed in remotely sensed orbital data from Mars. Our results can explain the present distribution of many clays on Mars, and the anomalously low density of the Martian crust in comparison with expectations.

Microstructural evolution in advanced boiler materials for ultra-supercritical coal power plants

NASA Astrophysics Data System (ADS)

Wu, Quanyan

The goal of improving the efficiency of pulverized coal powerplants has been pursued for decades. The need for greater efficiency and reduced environmental impact is pushing utilities to ultra supercritical conditions (USC), i.e. steam temperatures approaching 760°C under a stress of 35 MPa. The long-term creep strength and environmental resistance requirements imposed by these conditions are clearly beyond the capacity of the currently used ferritic steels and other conventional alloys. As part of a large DOE-funded consortium, new and existing materials based on advanced austenitic stainless steels and nickel base superalloys are being evaluated for these very demanding applications. In the present work, the nickel base superalloys of Inconel 617, CCA617, Haynes 230 and Inconel 740, and austenitic alloys Super 304H and HR6W, were evaluated on their microstructural properties over elevated temperature ageing and creep rupture conditions. The materials were aged for different lengths of time at temperatures relevant to USC applications, i.e., in the range from 700 to 800°C. The precipitation behaviors, namely of the gamma', carbides and eta phase in some conditions in nickel base superalloys, carbides in Haynes 230, Cu-rich precipitates in Super 304H and Laves phase particles in HR6W, were studied in detail using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and related analytical techniques. Particular attention has been given on the structure, morphology and compositional distinctiveness of various phases (including gamma, gamma', carbides, secondary phase precipitates, and other types of particles) and their nature, dislocation structures and other types of defects. The results were presented and discussed in light of associated changes in microhardness in the cases of aged samples, and in close reference to mechanical testing (including tensile and creep rupture tests) wherever available. Several mechanical strengthening

A SURVEY OF CONVENTIONAL STEAM BOILER EXPERIENCE APPLICABLE TO THE HTGR STEAM GENERATORS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paget, J.A.

1959-10-01

BS>The steam generator of a high temperature gas-cooled reactor consists of tubular heating surface inside a shell which forms part of the primary He circuit of the reactor. When a tube fails in such a steam generator, moisture in the form of steam is released into the He steam and is carried through the reactor where it will cause corrosion and mass transfer of C in the core. A paramount consideration in the design of a steam generator for a high temperature gas-cooled reactor is the prevention of tube failures. Preference, therefore, should be given to a forced circulation design.more » The Loeffler Boiler would be the best from this standpoint alone since only steam enters the tubes, and its circulation rate can be maintained at an adequate value to insure cool tubes regardless of load fluctuations. The next type in the order of preference would be the forced recirculation boiler, since at least the boiier tubes always have an adequate cooling flow regardless of output. The third type in order of preference would be a Sulzer Type boiler since it has a separator to remove dissolved material from the water which is comparible in efficiency to a standard boiler drum and although the flow through evaporator and superheater fluctuates with load, the Sulzer Boiler can be operated as a forced recirculation boiler at low loads. The least desirable type would be a Benson or supercritical boiler which is completely dependent on input water purity for its survival. It is not claimed that Benson or supercritical boilers should not or will not be used in the future for gas-cooled reactors, but only that their use would be the least conservative choice from a tube failure standpoint at the present time. (auth)« less

Ultra-high-performance supercritical fluid chromatography with quadrupole-time-of-flight mass spectrometry (UHPSFC/QTOF-MS) for analysis of lignin-derived monomeric compounds in processed lignin samples.

PubMed

Prothmann, Jens; Sun, Mingzhe; Spégel, Peter; Sandahl, Margareta; Turner, Charlotta

2017-12-01

The conversion of lignin to potentially high-value low molecular weight compounds often results in complex mixtures of monomeric and oligomeric compounds. In this study, a method for the quantitative and qualitative analysis of 40 lignin-derived compounds using ultra-high-performance supercritical fluid chromatography coupled to quadrupole-time-of-flight mass spectrometry (UHPSFC/QTOF-MS) has been developed. Seven different columns were explored for maximum selectivity. Makeup solvent composition and ion source settings were optimised using a D-optimal design of experiment (DoE). Differently processed lignin samples were analysed and used for the method validation. The new UHPSFC/QTOF-MS method showed good separation of the 40 compounds within only 6-min retention time, and out of these, 36 showed high ionisation efficiency in negative electrospray ionisation mode. Graphical abstract A rapid and selective method for the quantitative and qualitative analysis of 40 lignin-derived compounds using ultra-high-performance supercritical fluid chromatography coupled to quadrupole-time-of-flight mass spectrometry (UHPSFC/QTOF-MS).

Steam reforming of commercial ultra-low sulphur diesel

NASA Astrophysics Data System (ADS)

Boon, Jurriaan; van Dijk, Eric; de Munck, Sander; van den Brink, Ruud

Two main routes for small-scale diesel steam reforming exist: low-temperature pre-reforming followed by well-established methane steam reforming on the one hand and direct steam reforming on the other hand. Tests with commercial catalysts and commercially obtained diesel fuels are presented for both processes. The fuels contained up to 6.5 ppmw sulphur and up to 4.5 vol.% of biomass-derived fatty acid methyl ester (FAME). Pre-reforming sulphur-free diesel at around 475 °C has been tested with a commercial nickel catalyst for 118 h without observing catalyst deactivation, at steam-to-carbon ratios as low as 2.6. Direct steam reforming at temperatures up to 800 °C has been tested with a commercial precious metal catalyst for a total of 1190 h with two catalyst batches at steam-to-carbon ratios as low as 2.5. Deactivation was neither observed with lower steam-to-carbon ratios nor for increasing sulphur concentration. The importance of good fuel evaporation and mixing for correct testing of catalysts is illustrated. Diesel containing biodiesel components resulted in poor spray quality, hence poor mixing and evaporation upstream, eventually causing decreasing catalyst performance. The feasibility of direct high temperature steam reforming of commercial low-sulphur diesel has been demonstrated.

Comparison of ultra-high performance supercritical fluid chromatography and ultra-high performance liquid chromatography for the separation of spirostanol saponins.

PubMed

Zhu, Ling-Ling; Zhao, Yang; Xu, Yong-Wei; Sun, Qing-Long; Sun, Xin-Guang; Kang, Li-Ping; Yan, Ren-Yi; Zhang, Jie; Liu, Chao; Ma, Bai-Ping

2016-02-20

Spirostanol saponins are important active components of some herb medicines, and their isolation and purification are crucial for the research and development of traditional Chinese medicines. We aimed to compare the separation of spirostanol saponins by ultra-high performance supercritical fluid chromatography (UHPSFC) and ultra-high performance liquid chromatography (UHPLC). Four groups of spirostanol saponins were separated respectively by UHPSFC and UHPLC. After optimization, UHPSFC was performed with a HSS C18 SB column or a Diol column and with methanol as the co-solvent. A BEH C18 column and mobile phase containing water (with 0.1% formic acid) and acetonitrile were used in UHPLC. We found that UHPSFC could be performed automatically and quickly. It is effective in separating the spirostanol saponins which share the same aglycone and vary in sugar chains, and is very sensitive to the number and the position of hydroxyl groups in aglycones. However, the resolution of spirostanol saponins with different aglycones and the same sugar moiety by UHPSFC was not ideal and could be resolved by UHPLC instead. UHPLC is good at differentiating the variation in aglycones, and is influenced by double bonds in aglycones. Therefore, UHPLC and UHPSFC are complementary in separating spirostanol saponins. Considering the naturally produced spirostanol saponins in herb medicines are different both in aglycones and in sugar chains, a better separation can be achieved by combination of UHPLC and UHPSFC. UHPSFC is a powerful technique for improving the resolution when UHPLC cannot resolve a mixture of spirostanol saponins and vice versa. Copyright © 2015 Elsevier B.V. All rights reserved.

Features of steam turbine cooling by the example of an SKR-100 turbine for supercritical steam parameters

NASA Astrophysics Data System (ADS)

Arkadyev, B. A.

2015-10-01

Basic principles of cooling of high-temperature steam turbines and constructive solutions used for development of the world's first cooled steam turbine SKR-100 (R-100-300) are described. Principal differences between the thermodynamic properties of cooling medium in the steam and gas turbines and the preference of making flow passes of cooled cylinders of steam turbines as reactive are shown. Some of its operation results and their conclusions are given. This turbine with a power of 100 MW, initial steam parameters approximately 30 MPa and 650°C, and back pressure 3 MPa was made by a Kharkov turbine plant in 1961 and ran successfully at a Kashira GRES (state district power plant) up to 1979, when it was taken out of use in a still fully operating condition. For comparison, some data on construction features and operation results of the super-high pressure cylinder of steam turbines of American Philo 6 (made by General Electric Co.) and Eddystone 1 (made by Westinghouse Co.) power generating units, which are close to the SKR-100 turbine by design initial steam parameters and the implementation time, are given. The high operational reliability and effectiveness of the cooling system that was used in the super-high pressure cylinder of the SKR-100 turbine of the power-generating unit, which were demonstrated in operation, confirms rightfulness and expediency of principles and constructive solutions laid at its development. As process steam temperatures are increased, the realization of the proposed approach to cooling of multistage turbines makes it possible to limit for large turbine parts the application of new, more expensive high-temperature materials, which are required for making steam boilers, and, in some cases, to do completely away with their utilization.

Supercritical fluid extraction and ultra performance liquid chromatography of respiratory quinones for microbial community analysis in environmental and biological samples.

PubMed

Hanif, Muhammad; Atsuta, Yoichi; Fujie, Koichi; Daimon, Hiroyuki

2012-03-05

Microbial community structure plays a significant role in environmental assessment and animal health management. The development of a superior analytical strategy for the characterization of microbial community structure is an ongoing challenge. In this study, we developed an effective supercritical fluid extraction (SFE) and ultra performance liquid chromatography (UPLC) method for the analysis of bacterial respiratory quinones (RQ) in environmental and biological samples. RQ profile analysis is one of the most widely used culture-independent tools for characterizing microbial community structure. A UPLC equipped with a photo diode array (PDA) detector was successfully applied to the simultaneous determination of ubiquinones (UQ) and menaquinones (MK) without tedious pretreatment. Supercritical carbon dioxide (scCO(2)) extraction with the solid-phase cartridge trap proved to be a more effective and rapid method for extracting respiratory quinones, compared to a conventional organic solvent extraction method. This methodology leads to a successful analytical procedure that involves a significant reduction in the complexity and sample preparation time. Application of the optimized methodology to characterize microbial communities based on the RQ profile was demonstrated for a variety of environmental samples (activated sludge, digested sludge, and compost) and biological samples (swine and Japanese quail feces).

The thermal circuit of a nuclear power station's unit built around a supercritical-pressure water-cooled reactor

NASA Astrophysics Data System (ADS)

Silin, V. A.; Zorin, V. M.; Tagirov, A. M.; Tregubova, O. I.; Belov, I. V.; Povarov, P. V.

2010-12-01

Main results obtained from calculations of the steam generator and thermal circuit of the steam turbine unit for a nuclear power unit with supercritical-pressure water coolant and integral layout are presented. The obtained characteristics point to the advisability of carrying out further developments of this promising nuclear power technology.

Techno-economic analysis of supercritical carbon dioxide power blocks

NASA Astrophysics Data System (ADS)

Meybodi, Mehdi Aghaei; Beath, Andrew; Gwynn-Jones, Stephen; Veeraragavan, Anand; Gurgenci, Hal; Hooman, Kamel

2017-06-01

Developing highly efficient power blocks holds the key to enhancing the cost competitiveness of Concentration Solar Thermal (CST) technologies. Supercritical CO2 (sCO2) Brayton cycles have proved promising in providing equivalent or higher cycle efficiency than supercritical or superheated steam cycles at temperatures and scales relevant for Australian CST applications. In this study, a techno-economic methodology is developed using a stochastic approach to determine the ranges for the cost and performance of different components of central receiver power plants utilizing sCO2 power blocks that are necessary to meet the Australian Solar Thermal Initiative (ASTRI) final LCOE target of 12 c/kWh.

The vacuum system reform and test of the super-critical 600mw unit

NASA Astrophysics Data System (ADS)

Yan, Tao; Wan, Zhonghai; Lu, Jin; Chen, Wen; Cai, Wen

2017-11-01

The deficiencies of the designed vacuum system of the super-critical unit is pointed out in this paper, and then it is reformed by the steam ejector. The experimental results show that the vacuum of the condenser can be improved, the coal consumption can be reduced and the plant electricity consumption can be lowered dramatically at a small cost of the steam energy consumption. Meanwhile, the water-ring vacuum pumps cavitation problems can be solved.

Core design of a direct-cycle, supercritical-water-cooled fast breeder reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jevremovic, T.; Oka, Yoshiaki; Koshizuka, Seiichi

1994-10-01

The conceptual design of a direct-cycle fast breeder reactor (FBR) core cooled by supercritical water is carried out as a step toward a low-cost FBR plant. The supercritical water does not exhibit change of phase. The turbines are directly driven by the core outlet coolant. In comparison with a boiling water reactor (BWR), the recirculation systems, steam separators, and dryers are eliminated. The reactor system is much simpler than the conventional steam-cooled FBRs, which adopted Loeffler boilers and complicated coolant loops for generating steam and separating it from water. Negative complete and partial coolant void reactivity are provided without muchmore » deterioration in the breeding performances by inserting thin zirconium-hydride layers between the seeds and blankets in a radially heterogeneous core. The net electric power is 1245 MW (electric). The estimated compound system doubling time is 25 yr. The discharge burnup is 77.7 GWd/t, and the refueling period is 15 months with a 73% load factor. The thermal efficiency is high (41.5%), an improvement of 24% relative to a BWR's. The pressure vessel is not thick at 30.3 cm.« less

Development of High-Powered Steam Turbines by OAO NPO Central Research and Design Institute for Boilers and Turbines

NASA Astrophysics Data System (ADS)

Mikhailov, V. E.; Khomenok, L. A.; Kovalev, I. A.

2018-01-01

The article provides an overview of the developments by OAO NPO TsKTI aimed at improvement of components and assemblies of new-generation turbine plants for ultra-supercritical steam parameters to be installed at the power-generating facilities in service. The list of the assemblies under development includes cylinder shells, the cylinder's flow paths and rotors, seals, bearings, and rotor cooling systems. The authors consider variants of the shafting-cylinder configurations for which advanced high-pressure and intermediate-pressure cylinders with reactive blading and low-pressure cylinders of conventional design and with counter-current steam flows are proposed and high-pressure rotors, which can increase the economic efficiency and reduce the overall turbine plant dimensions. Materials intended for the equipment components that operate at high temperatures and a steam cooling technique that allows the use of cheaper steel grades owing to the reduction in the metal's working temperature are proposed. A new promising material for the bearing surfaces is described that enables the operation at higher unit pressures. The material was tested on a full-scale test bench at OAO NPO TsKTI and a turbine in operation. Ways of controlling the erosion of the blades in the moisture-steam turbine compartments by the steam heating of the hollow guide blades are considered. To ensure the dynamic stability of the shafting, shroud and diaphragm seals that prevent the development of the destabilizing circulatory forces of the steam flow were devised and trialed. Advanced instrumentation and software are proposed to monitor the condition of the blading and thermal stresses under transient conditions, to diagnose the vibration processes, and to archive the obtained data. Attention is paid to the normalization of the electromagnetic state of the plant in order to prevent the electrolytic erosion of the plant components. The instrumentation intended for monitoring the relevant electric

Simulation of high temperature thermal energy storage system based on coupled metal hydrides for solar driven steam power plants

DOE PAGES

d'Entremont, Anna; Corgnale, Claudio; Hardy, Bruce; ...

2018-01-11

Concentrating solar power plants can achieve low cost and efficient renewable electricity production if equipped with adequate thermal energy storage systems. Metal hydride based thermal energy storage systems are appealing candidates due to their demonstrated potential for very high volumetric energy densities, high exergetic efficiencies, and low costs. The feasibility and performance of a thermal energy storage system based on NaMgH 2F hydride paired with TiCr 1.6Mn 0.2 is examined, discussing its integration with a solar-driven ultra-supercritical steam power plant. The simulated storage system is based on a laboratory-scale experimental apparatus. It is analyzed using a detailed transport model accountingmore » for the thermochemical hydrogen absorption and desorption reactions, including kinetics expressions adequate for the current metal hydride system. The results show that the proposed metal hydride pair can suitably be integrated with a high temperature steam power plant. The thermal energy storage system achieves output energy densities of 226 kWh/m 3, 9 times the DOE SunShot target, with moderate temperature and pressure swings. Also, simulations indicate that there is significant scope for performance improvement via heat-transfer enhancement strategies.« less

Simulation of high temperature thermal energy storage system based on coupled metal hydrides for solar driven steam power plants

DOE Office of Scientific and Technical Information (OSTI.GOV)

d'Entremont, Anna; Corgnale, Claudio; Hardy, Bruce

Concentrating solar power plants can achieve low cost and efficient renewable electricity production if equipped with adequate thermal energy storage systems. Metal hydride based thermal energy storage systems are appealing candidates due to their demonstrated potential for very high volumetric energy densities, high exergetic efficiencies, and low costs. The feasibility and performance of a thermal energy storage system based on NaMgH 2F hydride paired with TiCr 1.6Mn 0.2 is examined, discussing its integration with a solar-driven ultra-supercritical steam power plant. The simulated storage system is based on a laboratory-scale experimental apparatus. It is analyzed using a detailed transport model accountingmore » for the thermochemical hydrogen absorption and desorption reactions, including kinetics expressions adequate for the current metal hydride system. The results show that the proposed metal hydride pair can suitably be integrated with a high temperature steam power plant. The thermal energy storage system achieves output energy densities of 226 kWh/m 3, 9 times the DOE SunShot target, with moderate temperature and pressure swings. Also, simulations indicate that there is significant scope for performance improvement via heat-transfer enhancement strategies.« less

Enantiomeric separation and quantification of R/S-amphetamine in urine by ultra-high performance supercritical fluid chromatography tandem mass spectrometry.

PubMed

Hegstad, S; Havnen, H; Helland, A; Spigset, O; Frost, J

2018-03-01

To distinguish between legal and illegal consumption of amphetamine reliable analytical methods for chiral separation of the R- and S-enantiomers of amphetamine in biological specimens are required. In this regard, supercritical fluid chromatography (SFC) has several potential advantages over liquid chromatography, including rapid separation of enantiomers due to low viscosity and high diffusivity of supercritical carbon dioxide, the main component in the SFC mobile phase. A method for enantiomeric separation and quantification of R- and S-amphetamine in urine was developed and validated using ultra-high performance supercritical fluid chromatography-tandem mass spectrometry (UHPSFC-MS/MS). Sample preparation prior to UHPSFC-MS/MS analysis was a semi-automatic solid phase extraction method. The UHPSFC-MS/MS method used a Chiralpak AD-3 column with a mobile phase consisting of CO 2 and 0.2% cyclohexylamine in 2-propanol. The injection volume was 2 μL and run-time was 6 min. MS/MS detection was performed with positive electrospray ionization and two multiple reaction monitoring transitions (m/z 136.1 > 119.0 and m/z 136.1 > 91.0). The calibration range was 50-10,000 ng/mL for each enantiomer. The between-assay relative standard deviations were in the range of 3.7-7.6%. Recovery was 92-93% and matrix effects ranged from 100 to 104% corrected with internal standard. After development and validation, the method has been successfully implemented in routine use at our laboratory for both separation and quantification of R/S-amphetamine, and has proved to be a reliable and useful tool for distinguishing intake of R- and S-amphetamine in authentic patient samples. Copyright © 2018 Elsevier B.V. All rights reserved.

[Comparison of Chemical Components of Essential Oil from Ocimum basilicum var. pilosum Extracted by Supercritical CO2 Fluid and Steam Distillation].

PubMed

Wang, Zhao-yu; Zheng, Jia-huan; Shi, Sheng-ying; Luo, Zhi-xiong; Ni, Shun-yu; Lin, Jing-ming

2015-11-01

To compare the chemical components of essential oil prepared by steam distillation extraction (SD) and supercritical CO2 fluid extraction (SFE-CO2) from Ocimum basilicum var. pilosum whole plant. The essential oil of Ocimum basilicum var. pilosum were extracted by SD and SFE-CO2. The chemical components of essential oil were separated and analyzed by gas chromatography-mass spectrometry( GC-MS). Their relative contents were determined by normalization of peak area. 40 and 42 compounds were detected in the essential oil prepared by SD and SFE-CO2 respectively. 25 compounds were common. Thereare significant differences of the chemical components between the Ocimum basilicum var. pilosum essential oil prepared by SD and thatby SFE-CO2. Different methods showed different extraction efficiency with a special compound. It might be a good idea to unite several methods in the modern traditional Chinese medicine industry.

Simple, rapid, and environmentally friendly method for the separation of isoflavones using ultra-high performance supercritical fluid chromatography.

PubMed

Wu, Wenjie; Zhang, Yuan; Wu, Hanqiu; Zhou, Weie; Cheng, Yan; Li, Hongna; Zhang, Chuanbin; Li, Lulu; Huang, Ying; Zhang, Feng

2017-07-01

Isoflavones are natural substances that exhibit hormone-like pharmacological activities. The separation of isoflavones remains an analytical challenge because of their similar structures. We show that ultra-high performance supercritical fluid chromatography can be an appropriate tool to achieve the fast separation of 12 common dietary isoflavones. Among the five tested columns the Torus DEA column was found to be the most effective column for the separation of these isoflavones. The impact of individual parameters on the retention time and separation factor was evaluated. These parameters were optimized to develop a simple, rapid, and green method for the separation of the 12 target analytes. It only took 12.91 min using gradient elution with methanol as an organic modifier and formic acid as an additive. These isoflavones were determined with limit of quantitation ranging from 0.10 to 0.50 μg/mL, which was sufficient for reliable determination of various matrixes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Recovery of Minerals in Martian Soils Via Supercritical Fluid Extraction

NASA Astrophysics Data System (ADS)

Debelak, Kenneth A.; Roth, John A.

2001-03-01

We are investigating the use of supercritical fluids to extract mineral and/or carbonaceous material from Martian surface soils and its igneous crust. Two candidate supercritical fluids are carbon dioxide and water. The Martian atmosphere is composed mostly of carbon dioxide (approx. 95.3%) and could therefore provide an in-situ source of carbon dioxide. Water, although present in the Martian atmosphere at only approx. 0.03%, is also a candidate supercritical solvent. Previous work done with supercritical fluids has focused primarily on their solvating properties with organic compounds. Interestingly, the first work reported by Hannay and Hogarth at a meeting of the Royal Society of London in 1879 observed that increasing or decreasing the pressure caused several inorganic salts e.g., cobalt chloride, potassium iodide, and potassium bromide, to dissolve or precipitate in supercritical ethanol. In high-pressure boilers, silica, present in most boiler feed waters, is dissolved in supercritical steam and transported as dissolved silica to the turbine blades. As the pressure is reduced the silica precipitates onto the turbine blades eventually requiring the shutdown of the generator. In supercritical water oxidation processes for waste treatment, dissolved salts present a similar problem. The solubility of silicon dioxide (SiO2) in supercritical water is shown. The solubility curve has a shape characteristic of supercritical systems. At a high pressure (greater than 1750 atmospheres) increasing the temperature results in an increase in solubility of silica, while at low pressures, less than 400 atm., the solubility decreases as temperature increases. There are only a few studies in the literature where supercritical fluids are used in extractive metallurgy. Bolt modified the Mond process in which supercritical carbon monoxide was used to produce nickel carbonyl (Ni(CO)4). Tolley and Tester studied the solubility of titanium tetrachloride (TiCl4) in supercritical CO2

Concept of turbines for ultrasupercritical, supercritical, and subcritical steam conditions

NASA Astrophysics Data System (ADS)

Mikhailov, V. E.; Khomenok, L. A.; Pichugin, I. I.; Kovalev, I. A.; Bozhko, V. V.; Vladimirskii, O. A.; Zaitsev, I. V.; Kachuriner, Yu. Ya.; Nosovitskii, I. A.; Orlik, V. G.

2017-11-01

The article describes the design features of condensing turbines for ultrasupercritical initial steam conditions (USSC) and large-capacity cogeneration turbines for super- and subcritical steam conditions having increased steam extractions for district heating purposes. For improving the efficiency and reliability indicators of USSC turbines, it is proposed to use forced cooling of the head high-temperature thermally stressed parts of the high- and intermediate-pressure rotors, reaction-type blades of the high-pressure cylinder (HPC) and at least the first stages of the intermediate-pressure cylinder (IPC), the double-wall HPC casing with narrow flanges of its horizontal joints, a rigid HPC rotor, an extended system of regenerative steam extractions without using extractions from the HPC flow path, and the low-pressure cylinder's inner casing moving in accordance with the IPC thermal expansions. For cogeneration turbines, it is proposed to shift the upper district heating extraction (or its significant part) to the feedwater pump turbine, which will make it possible to improve the turbine plant efficiency and arrange both district heating extractions in the IPC. In addition, in the case of using a disengaging coupling or precision conical bolts in the coupling, this solution will make it possible to disconnect the LPC in shifting the turbine to operate in the cogeneration mode. The article points out the need to intensify turbine development efforts with the use of modern methods for improving their efficiency and reliability involving, in particular, the use of relatively short 3D blades, last stages fitted with longer rotor blades, evaporation techniques for removing moisture in the last-stage diaphragm, and LPC rotor blades with radial grooves on their leading edges.

Investigation of thermal spray coatings on austenitic stainless steel substrate to enhance corrosion protection

NASA Astrophysics Data System (ADS)

Rogers, Daniel M.

The research is aimed to evaluate thermal spray coatings to address material issues in supercritical and ultra-supercritical Rankine cycles. The primary purpose of the research is to test, evaluate, and eventually implement a coating to improve corrosion resistance and increase efficiency of coal fired power plants. The research is performed as part of a comprehensive project to evaluate the ability of titanium, titanium carbide, or titanium diboride powders to provide fireside corrosion resistance in supercritical and ultra-supercritical steam boilers, specifically, coal driven boilers in Illinois that must utilize high sulfur and high chlorine content coal. [1] The powder coatings that were tested are nano-sized titanium carbide (TiC) and titanium di-boride (TiB2) powders that were synthesized by a patented process at Southern Illinois University. The powders were then sent to Gas Technology Institute in Chicago to coat steel coupons by HVOF (High Velocity Oxy-Fuel) thermal spray technique. The powders were coated on an austenitic 304H stainless steel substrate which is commonly found in high temperature boilers, pipelines, and heat exchangers. The samples then went through various tests for various lengths of time under subcritical, supercritical, and ultra-supercritical conditions. The samples were examined using a scanning electron microscope and x-ray diffraction techniques to study microstructural changes and then determined which coating performed best.

Methods of increasing thermal efficiency of steam and gas turbine plants

NASA Astrophysics Data System (ADS)

Vasserman, A. A.; Shutenko, M. A.

2017-11-01

Three new methods of increasing efficiency of turbine power plants are described. Increasing average temperature of heat supply in steam turbine plant by mixing steam after overheaters with products of combustion of natural gas in the oxygen. Development of this idea consists in maintaining steam temperature on the major part of expansion in the turbine at level, close to initial temperature. Increasing efficiency of gas turbine plant by way of regenerative heating of the air by gas after its expansion in high pressure turbine and before expansion in the low pressure turbine. Due to this temperature of air, entering combustion chamber, is increased and average temperature of heat supply is consequently increased. At the same time average temperature of heat removal is decreased. Increasing efficiency of combined cycle power plant by avoiding of heat transfer from gas to wet steam and transferring heat from gas to water and superheated steam only. Steam will be generated by multi stage throttling of the water from supercritical pressure and temperature close to critical, to the pressure slightly higher than condensation pressure. Throttling of the water and separation of the wet steam on saturated water and steam does not require complicated technical devices.

The utility of ultra-high performance supercritical fluid chromatography-tandem mass spectrometry (UHPSFC-MS/MS) for clinically relevant steroid analysis.

PubMed

Storbeck, Karl-Heinz; Gilligan, Lorna; Jenkinson, Carl; Baranowski, Elizabeth S; Quanson, Jonathan L; Arlt, Wiebke; Taylor, Angela E

2018-05-15

Liquid chromatography tandem mass spectrometry (LC-MS/MS) assays are considered the reference standard for serum steroid hormone analyses, while full urinary steroid profiles are only achievable by gas chromatography (GC-MS). Both LC-MS/MS and GC-MS have well documented strengths and limitations. Recently, commercial ultra-high performance supercritical fluid chromatography-tandem mass spectrometry (UHPSFC-MS/MS) systems have been developed. These systems combine the resolution of GC with the high-throughput capabilities of UHPLC. Uptake of this new technology into research and clinical labs has been slow, possibly due to the perceived increase in complexity. Here we therefore present fundamental principles of UHPSFC-MS/MS and the likely applications for this technology in the clinical research setting, while commenting on potential hurdles based on our experience to date. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Development of an Accelerated Methodology to Study Degradation of Materials in Supercritical Water for Application in High Temperature Power Plants

NASA Astrophysics Data System (ADS)

Rodriguez, David

stainless steel 316, Nitronic 50, Inconel 625 and Inconel 718 was exposed to supercritical water at 530 °C and ultra-supercritical water at 600 °C and was studied as a function exposure time. When exposed to supercritical water, Nitronic 50 and stainless steel 316 were observed to have similar mass gains; however, stainless steel 316 was found to gain less mass than Nitronic 50 in exposure tests performed in ultra-supercritical water. Stainless steel 316 developed surface films primarily composed of iron oxides, while the surface of Nitronic 50 contained a mixture of iron, chromium and manganese oxides. Inconels 625 and 718 samples were exposed to these temperatures for 24, 96, and 200 hours. Inconel 718 exhibited greater mass gain than Inconel 625 for all temperatures and exposure times. For the first time, corrosion rates in supercritical water were determined using electrochemical techniques. The corrosion rates of stainless steel 316, Nitronic 50, Inconel 625 and Inconel 718 were estimated in supercritical and ultra-supercritical water using electrochemical impedance spectroscopy and electrochemical frequency modulation. For all conditions tested, the corrosion rates obtained from electrochemical testing followed similar trends to the long-term gravimetric results. As a screening tool, this protocol can potentially reduce the time required for corrosion rate studies from thousands of hours to 24 hours.

Large Scale Screening of Low Cost Ferritic Steel Designs For Advanced Ultra Supercritical Boiler Using First Principles Methods

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ouyang, Lizhi

Advanced Ultra Supercritical Boiler (AUSC) requires materials that can operate in corrosive environment at temperature and pressure as high as 760°C (or 1400°F) and 5000psi, respectively, while at the same time maintain good ductility at low temperature. We develop automated simulation software tools to enable fast large scale screening studies of candidate designs. While direct evaluation of creep rupture strength and ductility are currently not feasible, properties such as energy, elastic constants, surface energy, interface energy, and stack fault energy can be used to assess their relative ductility and creeping strength. We implemented software to automate the complex calculations tomore » minimize human inputs in the tedious screening studies which involve model structures generation, settings for first principles calculations, results analysis and reporting. The software developed in the project and library of computed mechanical properties of phases found in ferritic steels, many are complex solid solutions estimated for the first time, will certainly help the development of low cost ferritic steel for AUSC.« less

Modeling and sliding mode predictive control of the ultra-supercritical boiler-turbine system with uncertainties and input constraints.

PubMed

Tian, Zhen; Yuan, Jingqi; Zhang, Xiang; Kong, Lei; Wang, Jingcheng

2018-05-01

The coordinated control system (CCS) serves as an important role in load regulation, efficiency optimization and pollutant reduction for coal-fired power plants. The CCS faces with tough challenges, such as the wide-range load variation, various uncertainties and constraints. This paper aims to improve the load tacking ability and robustness for boiler-turbine units under wide-range operation. To capture the key dynamics of the ultra-supercritical boiler-turbine system, a nonlinear control-oriented model is developed based on mechanism analysis and model reduction techniques, which is validated with the history operation data of a real 1000 MW unit. To simultaneously address the issues of uncertainties and input constraints, a discrete-time sliding mode predictive controller (SMPC) is designed with the dual-mode control law. Moreover, the input-to-state stability and robustness of the closed-loop system are proved. Simulation results are presented to illustrate the effectiveness of the proposed control scheme, which achieves good tracking performance, disturbance rejection ability and compatibility to input constraints. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Advanced steam power plant concepts with optimized life-cycle costs: A new approach for maximum customer benefit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seiter, C.

1998-07-01

The use of coal power generation applications is currently enjoying a renaissance. New highly efficient and cost-effective plant concepts together with environmental protection technologies are the main factors in this development. In addition, coal is available on the world market at attractive prices and in many places it is more readily available than gas. At the economical leading edge, standard power plant concepts have been developed to meet the requirements of emerging power markets. These concepts incorporate the high technological state-of-the-art and are designed to achieve lowest life-cycle costs. Low capital cost, fuel costs and operating costs in combination withmore » shortest lead times are the main assets that make these plants attractive especially for IPPs and Developers. Other aspects of these comprehensive concepts include turnkey construction and the willingness to participate in BOO/BOT projects. One of the various examples of such a concept, the 2 x 610-MW Paiton Private Power Project Phase II in Indonesia, is described in this paper. At the technological leading edge, Siemens has always made a major contribution and was pacemaker for new developments in steam power plant technology. Modern coal-fired steam power plants use computer-optimized process and plant design as well as advanced materials, and achieve efficiencies exceeding 45%. One excellent example of this high technology is the world's largest lignite-fired steam power plant Schwarze Pumpe in Germany, which is equipped with two 800 MW Siemens steam turbine generators with supercritical steam parameters. The world's largest 50-Hz single-shaft turbine generator with supercritical steam parameters rated at 1025 MW for the Niederaussem lignite-fired steam power plant in Germany is a further example of the sophisticated Siemens steam turbine technology and sets a new benchmark in this field.« less

Study on Dynamic Strain Aging and Low-Cycle Fatigue of Stainless Steel in Ultra-Supercritical Unit

NASA Astrophysics Data System (ADS)

Hongwei, Zhou; Yizhu, He; Jizu, Lv; Sixian, Rao

Dynamic strain aging (DSA) and low-cycle fatigue (LCF) behavior of TP347H stainless steel in ultra-supercritical unit were investigated at 550-650 °C. All the LCF tests were carried out under a fully-reversed, total axial strain control mode at the total strain amplitude from ±0.2% to ±1.0%. The effects of DSA in cyclic stress response, microstructure evolution and fatigue fracture surfaces and fatigue life were investigated in detail. The results show that DSA occurs during tensile, which is manifested as serrated flow in tensile stress-strain curves. The apparent activation energy for appearing of serrations in tensile stress-strain curves was 270 kJ/mol. Pipe diffusion of substitutional solutes such as Cr and Nb along the dislocation core, and strong interactions between segregated solutes and dislocations are considered as the mechanism of DSA. DSA partly restricts dislocation cross-slip, and dislocation cross-slip and planar-slip happen simultaneously during LCF. A lot of planar structures form, which is due to dislocation gliding on the special plane. This localized deformation structures result in many crack initiation sites. Meanwhile, DSA hardening increases cyclic stress response, accelerating crack propagation, which reduces high temperature strain fatigue life of steel.

Pyrite in contact with supercritical water: the desolation of steam.

PubMed

Stirling, András; Rozgonyi, Tamás; Krack, Matthias; Bernasconi, Marco

2015-07-14

The supercritical water-pyrite interface has been studied by ab initio molecular dynamics simulation. Extreme conditions are relevant in the iron-sulfur world (ISW) theory where prebiotic chemical reactions are postulated to occur at the mineral-water interface. We have investigated the properties of this interface under such conditions. We have come to the conclusion that hot-pressurized water on pyrite leads to an interface where a dry pyrite surface is in contact with the nearby SC water without significant chemical interactions. This picture is markedly different from that under ambient conditions where the surface is fully covered with adsorbed water molecules which is of relevance for the surface reactions of the ISW hypothesis.

Ultra-Low Density Organic-Inorganic Composite Materials Possessing Thermally Insulating and Acoustic Damping Properties

DTIC Science & Technology

1992-05-07

Officer. Dr. Kenneth Wynne d. Brief Description of Project- We are investigating the design and synthesis of strong, ultra-low density xerogel and aerogel ...materials of this type would have applications in a broad range of areas including lightweight engine components, high temperature coatings, aircraft wings...we plan to investigate the formation of ultra-low density composites using supercritical universal drying (SCUD) techniques. SiO2 aerogel materials

The State-of-the-Art of Materials Technology Used for Fossil and Nuclear Power Plants in China

NASA Astrophysics Data System (ADS)

Weng, Yuqing

Combined with the development of energy in China during the past 30 years, this paper clarified that high steam parameters ultra-supercritical (USC) coal-fired power plants and 1000MW nuclear power plants are the most important method to optimize energy structure and achieve national goals of energy saving and CO2 emission in China. Additionally, requirement of materials technology in high steam parameters USC coal-fired power plants and 1000MW nuclear power plants, current research and major development of relevant materials technology in China were briefly described in this paper.

Application of ultra-high performance supercritical fluid chromatography for the determination of carotenoids in dietary supplements.

PubMed

Li, Bing; Zhao, Haiyan; Liu, Jing; Liu, Wei; Fan, Sai; Wu, Guohua; Zhao, Rong

2015-12-18

A quick and simple ultra-high performance supercritical fluid chromatography-photodiode array detector method was developed and validated for the simultaneous determination of 9 carotenoids in dietary supplements. The influences of stationary phase, co-solvent, pressure, temperature and flow rate on the separation of carotenoids were evaluated. The separation of the carotenoids was carried out using an Acquity UPC(2) HSS C18 SB column (150mm×3.0mm, 1.8μm) by gradient elution with carbon dioxide and a 1:2 (v:v) methanol/ethanol mixture. The column temperature was set to 35°C and the backpressure was 15.2MPa. Under these conditions, 9 carotenoids and the internal standard, β-apo-8'-carotenal, were successfully separated within 10min. The correlation coefficients (R(2)) of the calibration curves were all above 0.997, the limits of detection for the 9 carotenoids were in the range of 0.33-1.08μg/mL, and the limits of quantification were in the range of 1.09-3.58μg/mL. The mean recoveries were from 93.4% to 109.5% at different spiking levels, and the relative standard deviations were between 0.8% and 6.0%. This method was successfully applied to the determination of 9 carotenoids in commercial dietary supplements. Copyright © 2015 Elsevier B.V. All rights reserved.

Novel Supercritical Carbon Dioxide Power Cycle Utilizing Pressured Oxy-combustion in Conjunction with Cryogenic Compression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brun, Klaus; McClung, Aaron; Davis, John

2014-03-31

The team of Southwest Research Institute® (SwRI) and Thar Energy LLC (Thar) applied technology engineering and economic analysis to evaluate two advanced oxy-combustion power cycles, the Cryogenic Pressurized Oxy-combustion Cycle (CPOC), and the Supercritical Oxy-combustion Cycle. This assessment evaluated the performance and economic cost of the two proposed cycles with carbon capture, and included a technology gap analysis of the proposed technologies to determine the technology readiness level of the cycle and the cycle components. The results of the engineering and economic analysis and the technology gap analysis were used to identify the next steps along the technology development roadmapmore » for the selected cycle. The project objectives, as outlined in the FOA, were 90% CO{sub 2} removal at no more than a 35% increase in cost of electricity (COE) as compared to a Supercritical Pulverized Coal Plant without CO{sub 2} capture. The supercritical oxy-combustion power cycle with 99% carbon capture achieves a COE of $121/MWe. This revised COE represents a 21% reduction in cost as compared to supercritical steam with 90% carbon capture ($137/MWe). However, this represents a 49% increase in the COE over supercritical steam without carbon capture ($80.95/MWe), exceeding the 35% target. The supercritical oxy-combustion cycle with 99% carbon capture achieved a 37.9% HHV plant efficiency (39.3% LHV plant efficiency), when coupling a supercritical oxy-combustion thermal loop to an indirect supercritical CO{sub 2} (sCO{sub 2}) power block. In this configuration, the power block achieved 48% thermal efficiency for turbine inlet conditions of 650°C and 290 atm. Power block efficiencies near 60% are feasible with higher turbine inlet temperatures, however a design tradeoff to limit firing temperature to 650°C was made in order to use austenitic stainless steels for the high temperature pressure vessels and piping and to minimize the need for advanced turbomachinery

Development and validation of ultra-high performance supercritical fluid chromatography method for determination of illegal dyes and comparison to ultra-high performance liquid chromatography method.

PubMed

Khalikova, Maria A; Šatínský, Dalibor; Solich, Petr; Nováková, Lucie

2015-05-18

A novel simple, fast and efficient ultra-high performance supercritical fluid chromatography (UHPSFC) method was developed and validated for the separation and quantitative determination of eleven illegal dyes in chili-containing spices. The method involved a simple ultrasound-assisted liquid extraction of illegal compounds with tetrahydrofuran. The separation was performed using a supercritical fluid chromatography system and CSH Fluoro-Phenyl stationary phase at 70°C. The mobile phase was carbon dioxide and the mixture of methanol:acetonitrile (1:1, v/v) with 2.5% formic acid as an additive at the flow rate 2.0 mL min(-1). The UV-vis detection was accomplished at 500 nm for seven compounds and at 420 nm for Sudan Orange G, Butter Yellow, Fast Garnet GBC and Methyl Red due to their maximum of absorbance. All eleven compounds were separated in less than 5 min. The method was successfully validated and applied using three commercial samples of chili-containing spices - Chili sauce (Indonesia), Feferony sauce (Slovakia) and Mojo sauce (Spain). The linearity range of proposed method was 0.50-9.09 mg kg(-1) (r ≥ 0.995). The detection limits were determined as signal to noise ratio of 3 and were ranged from 0.15 mg kg(-1) to 0.60 mg kg(-1) (1.80 mg kg(-1) for Fast Garnet) for standard solution and from 0.25 mg kg(-1) to 1.00 mg kg(-1) (2.50 mg kg(-1) for Fast Garnet, 1.50 mg kg(-1) for Sudan Red 7B) for chili-containing samples. The recovery values were in the range of 73.5-107.2% and relative standard deviation ranging from 0.1% to 8.2% for within-day precision and from 0.5% to 8.8% for between-day precision. The method showed potential for being used to monitor forbidden dyes in food constituents. The developed UHPSFC method was compared to the UHPLC-UV method. The orthogonality of Sudan dyes separation by these two methods was demonstrated. Benefits and drawbacks were discussed showing the reliability of both methods for monitoring of studied illegal dyes in real

Boiler materials for ultra-supercritical coal power plants - steamside oxidation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Viswanathan, R.; Sarver, J.; Tanzosh, J.M.

2006-06-15

The corrosion behavior of tubing materials carrying steam at high temperature is of great concern to fossil power plant operators. This is due to the fact that the oxide films formed on the steam side can lead to major failures and consequently to reduced plant availability. The wall loss of the pressure boundary caused by oxidation can increase the hoop stresses and cause premature creep failures; second, the increased insulation of the tubes due to the low thermal conductivity of the oxide film can lead to increased metal temperature, thereby exacerbating the fireside corrosion as well as creep problems. Themore » third concern is that thicker oxides may spall more easily when the plant is cooled down. On restart, the spalled material may lodge somewhere in the system with the potential for causing tube blockages, or it may be swept out with the working fluid and enter the steam turbine causing erosion damage to the turbine nozzles and blades. Failures of tubing and turbine components by these mechanisms have been widely reported in the United States. In view of the importance of the steamside oxidation, a major study of the phenomenon is being carried out as part of a major national program sponsored by the U.S. Department of Energy and the Ohio Coal Development Office. As a prelude to the experimental work, a literature survey was performed to document the state of the art. Results of the review are reported here.« less

Boiler materials for ultra-supercritical coal power plants—Steamside oxidation

NASA Astrophysics Data System (ADS)

Viswanathan, R.; Sarver, J.; Tanzosh, J. M.

2006-06-01

The corrosion behavior of tubing materials carrying steam at high temperature is of great concern to fossil power plant operators. This is due to the fact that the oxide films formed on the steam side can lead to major failures and consequently to reduced plant availability. The wall loss of the pressure boundary caused by oxidation can increase the hoop stresses and cause premature creep failures; second, the increased insulation of the tubes due to the low thermal conductivity of the oxide film can lead to increased metal temperature, thereby exacerbating the fireside corrosion as well as creep problems. The third concern is that thicker oxides may spall more easily when the plant is cooled down. On restart, the spalled material may lodge somewhere in the system with the potential for causing tube blockages, or it may be swept out with the working fluid and enter the steam turbine causing erosion damage to the turbine nozzles and blades. Failures of tubing and turbine components by these mechanisms have been widely reported in the United States. In view of the importance of the steamside oxidation, a major study of the phenomenon is being carried out as part of a major national program sponsored by the U.S. Department of Energy and the Ohio Coal Development Office. As a prelude to the experimental work, a literature survey was performed to document the state of the art. Results of the review are reported here.

Parameters optimization of supercritical fluid-CO2 extracts of frankincense using response surface methodology and its pharmacodynamics effects.

PubMed

Zhou, Jing; Ma, Xing-miao; Qiu, Bi-Han; Chen, Jun-xia; Bian, Lin; Pan, Lin-mei

2013-01-01

The volatile oil parts of frankincense (Boswellia carterii Birdw.) were extracted with supercritical carbon dioxide under constant pressure (15, 20, or 25 MPa) and fixed temperature (40, 50, or 60°C), given time (60, 90, or 120 min) aiming at the acquisition of enriched fractions containing octyl acetate, compounds of pharmaceutical interest. A mathematical model was created by Box-Behnken design, a popular template for response surface methodology, for the extraction process. The response value was characterized by synthetical score, which comprised yields accounting for 20% and content of octyl acetate for 80%. The content of octyl acetate was determined by GC. The supercritical fluid extraction showed higher selectivity than conventional steam distillation. Supercritical fluid-CO(2) for extracting frankincense under optimum condition was of great validity, which was also successfully verified by the pharmacological experiments. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Triacylglycerol compositions of sunflower, corn and soybean oils examined with supercritical CO2 ultra-performance convergence chromatography combined with quadrupole time-of-flight mass spectrometry.

PubMed

Gao, Boyan; Luo, Yinghua; Lu, Weiying; Liu, Jie; Zhang, Yaqiong; Yu, Liangli Lucy

2017-03-01

A supercritical CO 2 ultra-performance convergence chromatography (UPC 2 ) system was utilized with a quadrupole time-of-flight mass spectrometry (Q-TOF MS) to examine the triacylglycerol compositions of sunflower, corn and soybean oils. UPC 2 provided an excellent resolution and separation for the triacylglycerols, while the high performance Q-TOF MS system was able to provide the molecular weight and fragment ions information for triacylglycerol compound characterization. A total of 33 triacylglycerols were identified based on their elementary compositions and MS 2 fragment ion profiles, and their levels in the three oils were estimated. The combination of UPC 2 and Q-TOF MS may determine triacylglycerol compositions for oils and fats, and provide sn-position information for fatty acids, which may be important for food nutritional value and stability. Copyright © 2016 Elsevier Ltd. All rights reserved.

One-dimensional analysis of unsteady flows due to supercritical heat addition in high speed condensing steam

NASA Astrophysics Data System (ADS)

Malek, N. A.; Hasini, H.; Yusoff, M. Z.

2013-06-01

Unsteadiness in supersonic flow in nozzles can be generated by the release of heat due to spontaneous condensation. The heat released is termed "supercritical" and may be responsible for turbine blades failure in turbine cascade as it causes a supersonic flow to decelerate. When the Mach number is reduced to unity, the flow can no longer sustain the additional heat and becomes unstable. This paper aims to numerically investigate the unsteadiness caused by supercritical heat addition in one-dimensional condensing flows. The governing equations for mass, momentum and energy, coupled with the equations describing the wetness fraction and droplet growth are integrated and solved iteratively to reveal the final solution. Comparison is made with well-established experimental and numerical solution done by previous researchers that shows similar phenomena.

Supercritical Fuel Measurements

DTIC Science & Technology

2012-09-01

TERMS Fuels, supercritical fluids , stimulated scattering, Brillouin scattering, Rayleigh scattering, elastic properties, thermal properties 16...10 Supercritical Cell and Fluid Handling ....................................................................................... 11...motion in supercritical fluids . Thus, the method can perform diagnostics on the heat transfer of high-temperature and high-pressure fuels, measuring

Quantitative Determination of Cannabinoids in Cannabis and Cannabis Products Using Ultra-High-Performance Supercritical Fluid Chromatography and Diode Array/Mass Spectrometric Detection.

PubMed

Wang, Mei; Wang, Yan-Hong; Avula, Bharathi; Radwan, Mohamed M; Wanas, Amira S; Mehmedic, Zlatko; van Antwerp, John; ElSohly, Mahmoud A; Khan, Ikhlas A

2017-05-01

Ultra-high-performance supercritical fluid chromatography (UHPSFC) is an efficient analytical technique and has not been fully employed for the analysis of cannabis. Here, a novel method was developed for the analysis of 30 cannabis plant extracts and preparations using UHPSFC/PDA-MS. Nine of the most abundant cannabinoids, viz. CBD, ∆ 8 -THC, THCV, ∆ 9 -THC, CBN, CBG, THCA-A, CBDA, and CBGA, were quantitatively determined (RSDs < 6.9%). Unlike GC methods, no derivatization or decarboxylation was required prior to UHPSFC analysis. The UHPSFC chromatographic separation of cannabinoids displayed an inverse elution order compared to UHPLC. Combining with PDA-MS, this orthogonality is valuable for discrimination of cannabinoids in complex matrices. The developed method was validated, and the quantification results were compared with a standard UHPLC method. The RSDs of these two methods were within ±13.0%. Finally, chemometric analysis including principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used to differentiate between cannabis samples. © 2016 American Academy of Forensic Sciences.

Dry Air Cooler Modeling for Supercritical Carbon Dioxide Brayton Cycle Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moisseytsev, A.; Sienicki, J. J.; Lv, Q.

Modeling for commercially available and cost effective dry air coolers such as those manufactured by Harsco Industries has been implemented in the Argonne National Laboratory Plant Dynamics Code for system level dynamic analysis of supercritical carbon dioxide (sCO 2) Brayton cycles. The modeling can now be utilized to optimize and simulate sCO 2 Brayton cycles with dry air cooling whereby heat is rejected directly to the atmospheric heat sink without the need for cooling towers that require makeup water for evaporative losses. It has sometimes been stated that a benefit of the sCO 2 Brayton cycle is that it enablesmore » dry air cooling implying that the Rankine steam cycle does not. A preliminary and simple examination of a Rankine superheated steam cycle and an air-cooled condenser indicates that dry air cooling can be utilized with both cycles provided that the cycle conditions are selected appropriately« less

Supercritical Fuel Pyrolysis

DTIC Science & Technology

2010-05-30

supercritical fluids . These temperatures and pressures will also cause the fuel to undergo pyrolytic reactions, which have the potential of forming...With regard to physical properties, supercritical fluids have highly variable densities, no surface tension, and transport properties (i.e., mass...effects in supercritical fluids , often affecting chemical reaction pathways by facilitating the formation of certain transition states [6]. Because

Supercritical fluid extraction

DOEpatents

Wai, Chien M.; Laintz, Kenneth

1994-01-01

A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated or lipophilic crown ether or fluorinated dithiocarbamate. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.

Supercritical Fuel Pyrolysis

DTIC Science & Technology

2007-05-28

be supercritical fluids . These temperatures and pressures will also cause the fuel to undergo pyrolytic reactions, which have the potential of forming...physical properties, supercritical fluids have highly variable densities, no surface tension, and transport properties (i.e., mass, energy, and momentum...are very dependent on pressure, chemical reaction rates in supercritical fluids can be highly pressure-dependent [6-9]. The kinetic reaction rate

Enzymatic hydrolysis of chitin pretreated by rapid depressurization from supercritical 1,1,1,2-tetrafluoroethane toward highly acetylated oligosaccharides.

PubMed

Villa-Lerma, Guadalupe; González-Márquez, Humberto; Gimeno, Miquel; Trombotto, Stéphane; David, Laurent; Ifuku, Shinsuke; Shirai, Keiko

2016-06-01

The hydrolysis of chitin treated under supercritical conditions was successfully carried out using chitinases obtained by an optimized fermentation of the fungus Lecanicillium lecanii. The biopolymer was subjected to a pretreatment based on suspension in supercritical 1,1,1,2-tetrafluoroethane (scR134a), which possesses a critical temperature and pressure of 101°C and 40bar, respectively, followed by rapid depressurization to atmospheric pressure and further fibrillation. This methodology was compared to control untreated chitins and chitin subjected to steam explosion showing improved production of reducing sugars (0.18mg/mL), enzymatic hydrolysis and high acetylation (FA of 0.45) in products with degrees of polymerization between 2 and 5. Copyright © 2016 Elsevier Ltd. All rights reserved.

Efficient separation of curcumin, demethoxycurcumin, and bisdemethoxycurcumin from turmeric using supercritical fluid chromatography: From analytical to preparative scale.

PubMed

Song, Wei; Qiao, Xue; Liang, Wen-fei; Ji, Shuai; Yang, Lu; Wang, Yuan; Xu, Yong-wei; Yang, Ying; Guo, De-an; Ye, Min

2015-10-01

Curcumin is the major constituent of turmeric (Curcuma longa L.). It has attracted widespread attention for its anticancer and anti-inflammatory activities. The separation of curcumin and its two close analogs, demethoxycurcumin and bisdemethoxycurcumin, has been challenging by conventional techniques. In this study, an environmentally friendly method based on supercritical fluid chromatography was established for the rapid and facile separation of the three curcuminoids directly from the methanol extract of turmeric. The method was first developed and optimized by ultra performance convergence chromatography, and was then scaled up to preparative supercritical fluid chromatography. Eluted with supercritical fluid CO2 containing 8-15% methanol (containing 10 mM oxalic acid) at a flow rate of 80 mL/min, curcumin, demethoxycurcumin and bisdemethoxycurcumin could be well separated on a Viridis BEH OBD column (Waters, 250 mm × 19 mm, 5 μm) within 6.5 min. As a result, 20.8 mg of curcumin (97.9% purity), 7.0 mg of demethoxycurcumin (91.1%), and 4.6 mg of bisdemethoxycurcumin (94.8%) were obtained after a single step of supercritical fluid chromatography separation with a mean recovery of 76.6%. Showing obvious advantages in low solvent consumption, large sample loading, and easy solvent removal, supercritical fluid chromatography was proved to be a superior technique for the efficient separation of natural products. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of ultra-superheated steam on aflatoxin reduction and roasted peanut properties.

PubMed

Pukkasorn, Parawee; Ratphitagsanti, Wannasawat; Haruthaitanasan, Vichai

2018-06-01

Aflatoxins are carcinogenic toxins produced by Aspergillus flavus and Aspergillus parasiticus that are found naturally in peanut. It requires extremely high temperatures to eliminate aflatoxins from the nuts. The aims of this study were to investigate the effect of ultra-superheated steam (USS) on the reduction of aflatoxin B 1 (AFB 1 ) accompanying the roasting process and to determine roasted peanut qualities that affected consumer acceptance. Whole peanut kernels were intentionally contaminated by AFB 1 standard solution at the level of 50 ± 10 µg kg -1 before subjecting to USS treatment at 300-400 °C between 10 and 80 s. The high temperature of USS could significantly decrease AFB 1 level to 9.83 ± 3.51, 15.33 ± 2.23 and 8.95 ± 2.32 µg kg -1 when 300 °C for 80 s, 350 °C for 40 s and 400 °C for 40 s were employed, respectively. AFB 1 was reduced as much as 83.86 ± 2.66% when 400 °C for 40 s was applied. The moisture content of treated peanuts was decreased to less than 3% and browning index was developed from 30.96 ± 1.59 to 95.76 ± 7.23. Higher roasting degree was obtained according to the increase in browning index. Oil quality showed that peroxide values and acid values were greatly below the allowance level. USS could effectively decrease AFB 1 and render expectable roasting qualities of peanut. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Solid catalyzed isoparaffin alkylation at supercritical fluid and near-supercritical fluid conditions

DOEpatents

Ginosar, Daniel M.; Fox, Robert V.; Kong, Peter C.

2000-01-01

This invention relates to an improved method for the alkylation reaction of isoparaffins with olefins over solid catalysts including contacting a mixture of an isoparaffin, an olefin and a phase-modifying material with a solid acid catalyst member under alkylation conversion conditions at either supercritical fluid, or near-supercritical fluid conditions, at a temperature and a pressure relative to the critical temperature(T.sub.c) and the critical pressure(P.sub.c) of the reaction mixture. The phase-modifying phase-modifying material is employed to promote the reaction's achievement of either a supercritical fluid state or a near-supercritical state while simultaneously allowing for decreased reaction temperature and longer catalyst life.

Tensile and creep deformation of a newly developed Ni-Fe-based superalloy for 700 °C advanced ultra-supercritical boiler applications

NASA Astrophysics Data System (ADS)

Yuan, Y.; Zhong, Z. H.; Yu, Z. S.; Yin, H. F.; Dang, Y. Y.; Zhao, X. B.; Yang, Z.; Lu, J. T.; Yan, J. B.; Gu, Y.

2015-07-01

A new Ni-Fe-based superalloy, HT-X, has been developed for applications in 700 °C advanced ultra-supercritical (A-USC) boilers. The HT-X alloy is subjected to various heat treatments. Tensile tests are conducted at room temperature (RT), 700 °C and 750 °C. Creep tests are carried out under conditions of 700 °C/300 MPa and 750 °C/150 MPa. After aging treatment, the yield strength of the HT-X alloy at RT and 750 °C is 787 MPa and 624 MPa, respectively. When additional thermal exposure at 750 °C for 5400 h is applied, the yield strength is decreased to 656 MPa at RT and 480 MPa at 700 °C. For an aged specimen, the a/2<110>dislocation shearing process occurs when tensile testing is conducted at RT and 750 °C. As the γ' precipitate size increases in the specimen that is thermally exposed at 750 °C for 5400 h, Orowan bowing is the dominant dislocation process, and stacking faults develop in the γ' precipitates at both RT and 700 °C. Dislocation slip combined with climb is the dominant mechanism under the creep testing conditions. The factors that affect the mechanical properties and deformation mechanisms are discussed.

Prospects for development of an innovative water-cooled nuclear reactor for supercritical parameters of coolant

NASA Astrophysics Data System (ADS)

Kalyakin, S. G.; Kirillov, P. L.; Baranaev, Yu. D.; Glebov, A. P.; Bogoslovskaya, G. P.; Nikitenko, M. P.; Makhin, V. M.; Churkin, A. N.

2014-08-01

The state of nuclear power engineering as of February 1, 2014 and the accomplished elaborations of a supercritical-pressure water-cooled reactor are briefly reviewed, and the prospects of this new project are discussed based on this review. The new project rests on the experience gained from the development and operation of stationary water-cooled reactor plants, including VVERs, PWRs, BWRs, and RBMKs (their combined service life totals more than 15 000 reactor-years), and long-term experience gained around the world with operation of thermal power plants the turbines of which are driven by steam with supercritical and ultrasupercritical parameters. The advantages of such reactor are pointed out together with the scientific-technical problems that need to be solved during further development of such installations. The knowledge gained for the last decade makes it possible to refine the concept and to commence the work on designing an experimental small-capacity reactor.

1300°F 800 MWe USC CFB Boiler Design Study

NASA Astrophysics Data System (ADS)

Robertson, Archie; Goidich, Steve; Fan, Zhen

Concern about air emissions and the effect on global warming is one of the key factors for developing and implementing new advanced energy production solutions today. One state-of-the-art solution is circulating fluidized bed (CFB) combustion technology combined with a high efficiency once-through steam cycle. Due to this extremely high efficiency, the proven CFB technology offers a good solution for CO2 reduction. Its excellent fuel flexibility further reduces CO2 emissions by co-firing coal with biomass. Development work is under way to offer CFB technology up to 800MWe capacities with ultra-supercritical (USC) steam parameters. In 2009 a 460MWe once-through supercritical (OTSC) CFB boiler designed and constructed by Foster Wheeler will start up. However, scaling up the technology further to 600-800MWe with net efficiency of 45-50% is needed to meet the future requirements of utility operators. To support the move to these larger sizes, an 800MWe CFB boiler conceptual design study was conducted and is reported on herein. The use of USC conditions (˜11 00°F steam) was studied and then the changes, that would enable the unit to generate 1300°F steam, were identified. The study has shown that by using INTREX™ heat exchangers in a unique internal-external solids circulation arrangement, Foster Wheeler's CFB boiler configuration can easily accommodate 1300°F steam and will not require a major increase in heat transfer surface areas.

Hydrogen production from high moisture content biomass in supercritical water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Antal, M.J. Jr.; Xu, X.

1998-08-01

By mixing wood sawdust with a corn starch gel, a viscous paste can be produced that is easily delivered to a supercritical flow reactor by means of a cement pump. Mixtures of about 10 wt% wood sawdust with 3.65 wt% starch are employed in this work, which the authors estimate to cost about $0.043 per lb. Significant reductions in feed cost can be achieved by increasing the wood sawdust loading, but such an increase may require a more complex pump. When this feed is rapidly heated in a tubular flow reactor at pressures above the critical pressure of water (22more » MPa), the sawdust paste vaporizes without the formation of char. A packed bed of carbon catalyst in the reactor operating at about 650 C causes the tarry vapors to react with water, producing hydrogen, carbon dioxide, and some methane with a trace of carbon monoxide. The temperature and history of the reactor`s wall influence the hydrogen-methane product equilibrium by catalyzing the methane steam reforming reaction. The water effluent from the reactor is clean. Other biomass feedstocks, such as the waste product of biodiesel production, behave similarly. Unfortunately, sewage sludge does not evidence favorable gasification characteristics and is not a promising feedstock for supercritical water gasification.« less

A Comparison of Supercritical Carbon Dioxide Power Cycle Configurations with an Emphasis on CSP Applications (Presentation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Neises, T.; Turchi, C.

2013-09-01

Recent research suggests that an emerging power cycle technology using supercritical carbon dioxide (s-CO2) operated in a closed-loop Brayton cycle offers the potential of equivalent or higher cycle efficiency versus supercritical or superheated steam cycles at temperatures relevant for CSP applications. Preliminary design-point modeling suggests that s-CO2 cycle configurations can be devised that have similar overall efficiency but different temperature and/or pressure characteristics. This paper employs a more detailed heat exchanger model than previous work to compare the recompression and partial cooling cycles, two cycles with high design-point efficiencies, and illustrates the potential advantages of the latter. Integration of themore » cycles into CSP systems is studied, with a focus on sensible heat thermal storage and direct s-CO2 receivers. Results show the partial cooling cycle may offer a larger temperature difference across the primary heat exchanger, thereby potentially reducing heat exchanger cost and improving CSP receiver efficiency.« less

Supercritical crystallization: The RESs-process and the GAS-process

NASA Astrophysics Data System (ADS)

Berends, Edwin M.

1994-09-01

This Doctoral Ph.D. thesis describes the development of two novel crystallization processes utilizing supercritical fluids either as a solvent, the RESS-process, or as an anti-solvent, the GAS-process. In th RESS-process precipitation of the solute is performed by expansion of the solution over a nozzle to produce ultra-fine, monodisperse particles without any solvent inclusions. In the GAS-process a high pressure gas is dissolved into the liquid phase solvent, where it causes a volumetric expansion of this liquid solvent and lowers the equilibrium solubility. Particle size, particle size distribution and other particle characteristics such as their shape, internal structure and the residual amount of solvent in the particles are expected to be influenced by the liquid phase expansion profile.

Supercritical Fluid Fractionation of JP-8

DTIC Science & Technology

1991-12-26

applications, such as coffee decaffeination , spice extraction, and lipids purification. The processing principles have also long been well known and ipracticed...PRINCIPLES OF SUPERCRITICAL FLUID EXTRACTION 8 A. Background on Supercritical Fluid Solubility 8 B. Supercritical Fluid Extraction Process ...Operation I0 1. Batch Extraction of Solid Materials 10 2. Counter-Current Continuous SCF Processing of Liquid 15 Products 3. Supercritical Fluid Extraction vs

Study of UltraHigh Performance Supercritical Fluid Chromatography to measure free fatty acids with out fatty acid ester preparation.

PubMed

Ashraf-Khorassani, M; Isaac, G; Rainville, P; Fountain, K; Taylor, L T

2015-08-01

Most lipids are best characterized by their fatty acids which may differ in (a) chain length, (b) degree of unsaturation, (c) configuration and position of the double bonds, and (d) the presence of other functionalities. Thus, a fast, simple, and quantitative analytical technique to determine naturally occurring free fatty acids (FFA) in different samples is very important. Just as for saponified acylglycerols, the determination of FFA's has generally been carried out by high resolution gas chromatography (HRGC). The use of an open tubular capillary column coupled with a flame ionization or mass spectrometric detector provides for both high resolution and quantification of FFA's but only after conversion of all free fatty acids to fatty acid methyl esters (FAME) or pentafluorobenzyl esters. Unfortunately, volatilization of labile ester derivatives of mono- and poly-unsaturated FFA's can cause both thermal degradation and isomerization of the fatty acid during HRGC. The employment of a second generation instrument (here referred to as UltraHigh Performance Supercritical Fluid Chromatograph, UHPSFC) with high precision for modified flow and repeated back pressure adjustment in conjunction with sub-2μm various bonded silica particles (coupled with evaporative light scattering, ELSD, and mass spectrometric, MS, detection) for separation and detection of the following mixtures is described: (a) 31 free fatty acids, (b) isomeric FFA's, and (c) lipophilic materials in two real world fish oil samples. Limits of detection for FFA's via UHPSFC/MS and UHPSFC/ELSD versus detection of FAME's via HRGC/MS are quantitatively compared. Copyright © 2015 Elsevier B.V. All rights reserved.

Ultra-Fast Supercritical Hydrothermal Synthesis of Tobermorite under Thermodynamically Metastable Conditions.

PubMed

Diez-Garcia, Marta; Gaitero, Juan J; Dolado, Jorge S; Aymonier, Cyril

2017-03-13

Tobermorite is a fibrillar mineral of the family of calcium silicates. In spite of not being abundant in nature, its structure and properties are reasonably well known because of its interest in the construction industry. Currently, tobermorite is synthesized by hydrothermal methods at mild temperatures. The problem is that such processes are very slow (>5 h) and temperature cannot be increased to speed them up because tobermorite is metastable over 130 °C. Furthermore the product obtained is generally foil-like and not very crystalline. Herein we propose an alternative synthesis method based on the use of a continuous flow reactor and supercritical water. In spite of the high temperature, the transformation of tobermorite to more stable phases can be prevented by accurately controlling the reaction time. As a result, highly crystalline fibrillar tobermorite can be obtained in just a few seconds under thermodynamically metastable conditions. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Kinetics of Supercritical Water Oxidation

DTIC Science & Technology

1995-12-31

milestone and Sandia Technical Report. A much-needed report describing in detail the operation of the Supercritical Fluids Reactor (SFR) was also...years. In addition, the literature research required to arrive at this optimal design will be used to improve the performance of the Supercritical Fluids ...the Supercritical Fluids Reactor (SFR)" (Sandia National Laboratories Report SAND-8203, Livermore, CA, 1995). R. R. Steeper, "Methane and Methanol

Materials for advanced ultrasupercritical steam turbines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Purgert, Robert; Shingledecker, John; Saha, Deepak

The U.S. Department of Energy (DOE) and the Ohio Coal Development Office (OCDO) have sponsored a project aimed at identifying, evaluating, and qualifying the materials needed for the construction of the critical components of coal-fired power plants capable of operating at much higher efficiencies than the current generation of supercritical plants. This increased efficiency is expected to be achieved principally through the use of advanced ultrasupercritical (A-USC) steam conditions. A limiting factor in this can be the materials of construction for boilers and for steam turbines. The overall project goal is to assess/develop materials technology that will enable achieving turbinemore » throttle steam conditions of 760°C (1400°F)/35MPa (5000 psi). This final technical report covers the research completed by the General Electric Company (GE) and Electric Power Research Institute (EPRI), with support from Oak Ridge National Laboratory (ORNL) and the National Energy Technology Laboratory (NETL) – Albany Research Center, to develop the A-USC steam turbine materials technology to meet the overall project goals. Specifically, this report summarizes the industrial scale-up and materials property database development for non-welded rotors (disc forgings), buckets (blades), bolting, castings (needed for casing and valve bodies), casting weld repair, and casting to pipe welding. Additionally, the report provides an engineering and economic assessment of an A-USC power plant without and with partial carbon capture and storage. This research project successfully demonstrated the materials technology at a sufficient scale and with corresponding materials property data to enable the design of an A-USC steam turbine. The key accomplishments included the development of a triple-melt and forged Haynes 282 disc for bolted rotor construction, long-term property development for Nimonic 105 for blading and bolting, successful scale-up of Haynes 282 and Nimonic 263 castings using

Electrochemistry in supercritical fluids

PubMed Central

Branch, Jack A.; Bartlett, Philip N.

2015-01-01

A wide range of supercritical fluids (SCFs) have been studied as solvents for electrochemistry with carbon dioxide and hydrofluorocarbons (HFCs) being the most extensively studied. Recent advances have shown that it is possible to get well-resolved voltammetry in SCFs by suitable choice of the conditions and the electrolyte. In this review, we discuss the voltammetry obtained in these systems, studies of the double-layer capacitance, work on the electrodeposition of metals into high aspect ratio nanopores and the use of metallocenes as redox probes and standards in both supercritical carbon dioxide–acetonitrile and supercritical HFCs. PMID:26574527

Energetic approach of biomass hydrolysis in supercritical water.

PubMed

Cantero, Danilo A; Vaquerizo, Luis; Mato, Fidel; Bermejo, M Dolores; Cocero, M José

2015-03-01

Cellulose hydrolysis can be performed in supercritical water with a high selectivity of soluble sugars. The process produces high-pressure steam that can be integrated, from an energy point of view, with the whole biomass treating process. This work investigates the integration of biomass hydrolysis reactors with commercial combined heat and power (CHP) schemes, with special attention to reactor outlet streams. The innovation developed in this work allows adequate energy integration possibilities for heating and compression by using high temperature of the flue gases and direct shaft work from the turbine. The integration of biomass hydrolysis with a CHP process allows the selective conversion of biomass into sugars with low heat requirements. Integrating these two processes, the CHP scheme yield is enhanced around 10% by injecting water in the gas turbine. Furthermore, the hydrolysis reactor can be held at 400°C and 23 MPa using only the gas turbine outlet streams. Copyright © 2014 Elsevier Ltd. All rights reserved.

Steam drum design for direct steam generation

NASA Astrophysics Data System (ADS)

Willwerth, Lisa; Müller, Svenja; Krüger, Joachim; Succo, Manuel; Feldhoff, Jan Fabian; Tiedemann, Jörg; Pandian, Yuvaraj; Krüger, Dirk; Hennecke, Klaus

2017-06-01

For the direct steam generation in solar fields, the recirculation concept has been demonstrated in several installations. Water masses in the solar field vary during transient phases, such as passing clouds. The volume of the steam drum can serve as a buffer during such transients by taking in excess water and providing water storage. The saturated steam mass flow to the superheating section or the consumer can be maintained almost constant during short transients; therefore the steam drum plays a key role for constant steam supply. Its buffer effect depends on the right sizing of the steam drum for the prevailing situations. Due to missing experiences, steam drums have been sized under conservative assumptions and are thereby usually oversized. With this paper, experiences on the steam drum of the 5 MWel TSE1 power plant are discussed for optimized future plant design. The results are also of relevance for process heat installations, in which saturated steam is produced by the solar field.

Supercritical water oxidation - Microgravity solids separation

NASA Technical Reports Server (NTRS)

Killilea, William R.; Hong, Glenn T.; Swallow, Kathleen C.; Thomason, Terry B.

1988-01-01

This paper discusses the application of supercritical water oxidation (SCWO) waste treatment and water recycling technology to the problem of waste disposal in-long term manned space missions. As inorganic constituents present in the waste are not soluble in supercritical water, they must be removed from the organic-free supercritical fluid reactor effluent. Supercritical water reactor/solids separator designs capable of removing precipitated solids from the process' supercritical fluid in zero- and low- gravity environments are developed and evaluated. Preliminary experiments are then conducted to test the concepts. Feed materials for the experiments are urine, feces, and wipes with the addition of reverse osmosis brine, the rejected portion of processed hygiene water. The solid properties and their influence on the design of several oxidation-reactor/solids-separator configurations under study are presented.

Advanced Thermal Storage for Central Receivers with Supercritical Coolants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kelly, Bruce D.

2010-06-15

The principal objective of the study is to determine if supercritical heat transport fluids in a central receiver power plant, in combination with ceramic thermocline storage systems, offer a reduction in levelized energy cost over a baseline nitrate salt concept. The baseline concept uses a nitrate salt receiver, two-tank (hot and cold) nitrate salt thermal storage, and a subcritical Rankine cycle. A total of 6 plant designs were analyzed, as follows: Plant Designation Receiver Fluid Thermal Storage Rankine Cycle Subcritical nitrate salt Nitrate salt Two tank nitrate salt Subcritical Supercritical nitrate salt Nitrate salt Two tank nitrate salt Supercritical Lowmore » temperature H2O Supercritical H2O Two tank nitrate salt Supercritical High temperature H2O Supercritical H2O Packed bed thermocline Supercritical Low temperature CO2 Supercritical CO2 Two tank nitrate salt Supercritical High temperature CO2 Supercritical CO2 Packed bed thermocline Supercritical Several conclusions have been drawn from the results of the study, as follows: 1) The use of supercritical H2O as the heat transport fluid in a packed bed thermocline is likely not a practical approach. The specific heat of the fluid is a strong function of the temperatures at values near 400 °C, and the temperature profile in the bed during a charging cycle is markedly different than the profile during a discharging cycle. 2) The use of supercritical CO2 as the heat transport fluid in a packed bed thermocline is judged to be technically feasible. Nonetheless, the high operating pressures for the supercritical fluid require the use of pressure vessels to contain the storage inventory. The unit cost of the two-tank nitrate salt system is approximately $24/kWht, while the unit cost of the high pressure thermocline system is nominally 10 times as high. 3) For the supercritical fluids, the outer crown temperatures of the receiver tubes are in the range of 700 to 800 °C. At temperatures of 700 °C and above

Supercritical transitiometry of polymers.

PubMed

Randzio, S L; Grolier, J P

1998-06-01

Employing supercritical fluids (SCFs) during polymers processing allows the unusual properties of SCFs to be exploited for making polymer products that cannot be obtained by other means. A new supercritical transitiometer has been constructed to permit study of the interactions of SCFs with polymers during processing under well-defined conditions of temperature and pressure. The supercritical transitiometer allows pressure to be exerted by either a supercritical fluid or a neutral medium and enables simultaneous determination of four basic parameters of a transition, i.e., p, T, Δ(tr)H and Δ(tr)V. This permits determination of the SCF effect on modification of the polymer structure at a given pressure and temperature and defines conditions to allow reproducible preparation of new polymer structures. Study of a semicrystalline polyethylene by this method has defined conditions for preparation of new microfoamed phases with good mechanical properties. The low densities and microporous structures of the new materials may make them useful for applications in medicine, pharmacy, or the food industry, for example.

Electrodeposition of metals from supercritical fluids

PubMed Central

Ke, Jie; Su, Wenta; Howdle, Steven M.; George, Michael W.; Cook, David; Perdjon-Abel, Magda; Bartlett, Philip N.; Zhang, Wenjian; Cheng, Fei; Levason, William; Reid, Gillian; Hyde, Jason; Wilson, James; Smith, David C.; Mallik, Kanad; Sazio, Pier

2009-01-01

Electrodeposition is a widely used materials-deposition technology with a number of unique features, in particular, the efficient use of starting materials, conformal, and directed coating. The properties of the solvent medium for electrodeposition are critical to the technique's applicability. Supercritical fluids are unique solvents which give a wide range of advantages for chemistry in general, and materials processing in particular. However, a widely applicable approach to electrodeposition from supercritical fluids has not yet been developed. We present here a method that allows electrodeposition of a range of metals from supercritical carbon dioxide, using acetonitrile as a co-solvent and supercritical difluoromethane. This method is based on a careful selection of reagent and supporting electrolyte. There are no obvious barriers preventing this method being applied to deposit a range of materials from many different supercritical fluids. We present the deposition of 3-nm diameter nanowires in mesoporous silica templates using this methodology. PMID:19706479

Supercritical fluid chromatography

NASA Astrophysics Data System (ADS)

Vigdergauz, M. S.; Lobachev, A. L.; Lobacheva, I. V.; Platonov, I. A.

1992-03-01

The characteristic features of supercritical fluid chromatography (SCFC) are examined and there is a brief historical note concerning the development of the method. Information concerning the use of supercritical fluid chromatography in the analysis of objects of different nature is presented in the form of a table. The roles of the mobile and stationary phases in the separation process and the characteristic features of the apparatus and of the use of the method in physicochemical research are discussed. The bibliography includes 364 references.

Oxy-combustor operable with supercritical fluid

DOEpatents

Brun, Klaus; McClung, Aaron M.; Owston, Rebecca A.

2017-04-04

An oxy-combustor is provided which comprises a combustion vessel including at least one solid fuel slurry inlet port, at least one oxygen inlet port and at least one supercritical fluid inlet port, wherein the combustion vessel is operable at an operating pressure of at least 1,100 psi; an interior of the combustion vessel comprises a combustion chamber and a supercritical fluid infusion chamber surrounding at least a part of the combustion chamber, the supercritical fluid infusion chamber and the combustion chamber are separated by a porous liner surrounding the combustion chamber, and the supercritical infusion chamber is located between the porous liner and an outer casing of the combustion vessel.

Comparative analysis of gas and coal-fired power generation in ultra-low emission condition using life cycle assessment (LCA)

NASA Astrophysics Data System (ADS)

Yin, Libao; Liao, Yanfen; Liu, Guicai; Liu, Zhichao; Yu, Zhaosheng; Guo, Shaode; Ma, Xiaoqian

2017-05-01

Energy consumption and pollutant emission of natural gas combined cycle power-generation (NGCC), liquefied natural gas combined cycle power-generation (LNGCC), natural gas combined heat and power generation (CHP) and ultra-supercritical power generation with ultra-low gas emission (USC) were analyzed using life cycle assessment method, pointing out the development opportunity and superiority of gas power generation in the period of coal-fired unit ultra-low emission transformation. The results show that CO2 emission followed the order: USC>LNGCC>NGCC>CHP the resource depletion coefficient of coal-fired power generation was lower than that of gas power generation, and the coal-fired power generation should be the main part of power generation in China; based on sensitivity analysis, improving the generating efficiency or shortening the transportation distance could effectively improve energy saving and emission reduction, especially for the coal-fired units, and improving the generating efficiency had a great significance for achieving the ultra-low gas emission.

Steam atmosphere drying exhaust steam recompression system

DOEpatents

Becker, F.E.; Smolensky, L.A.; Doyle, E.F.; DiBella, F.A.

1994-03-08

This invention relates to a heated steam atmosphere drying system comprising dryer in combination with an exhaust recompression system which is extremely energy efficient and eliminates dangers known to air dryers. The system uses superheated steam as the drying medium, which recirculates through the system where its heat of evaporation and heat of compression is recovered, thereby providing a constant source of heat to the drying chamber. The dryer has inlets whereby feedstock and superheated steam are fed therein. High heat transfer and drying rates are achieved by intimate contact of the superheated steam with the particles being dried. The dryer comprises a vessel which enables the feedstock and steam to enter and recirculate together. When the feedstock becomes dry it will exit the dryer with the steam and become separated from the steam through the use of a curvilinear louver separator (CLS). The CLS enables removal of fine and ultrafine particles from the dryer. Water vapor separated from the particles in the CLS as superheated steam, may then be recovered and recirculated as steam through the use of a compressor to either directly or indirectly heat the dryer, and a heat exchanger or a heater to directly provide heat to the dryer. This system not only provides a very efficient heat transfer system but results in a minimum carry-over of ultrafine particles thereby eliminating any explosive hazard. 17 figures.

Steam atmosphere drying exhaust steam recompression system

DOEpatents

Becker, Frederick E.; Smolensky, Leo A.; Doyle, Edward F.; DiBella, Francis A.

1994-01-01

This invention relates to a heated steam atmosphere drying system comprising dryer in combination with an exhaust recompression system which is extremely energy efficient and eliminates dangers known to air dryers. The system uses superheated steam as the drying medium, which recirculated through the system where its heat of evaporation and heat of compression is recovered, thereby providing a constant source of heat to the drying chamber. The dryer has inlets whereby feedstock and superheated steam are fed therein. High heat transfer and drying rates are achieved by intimate contact of the superheated steam with the particles being dried The dryer comprises a vessel which enables the feedstock and steam to enter recirculate together. When the feedstock becomes dry it will exit the dryer with the steam and become separated from the steam through the use of a curvilinear louver separator (CLS). The CLS enables removal of fine and ultrafine particles from the dryer. Water vapor separated from the particles in the CLS as superheated steam, may then be recovered and recirculated as steam through the use of a compressor to either directly or indirectly heat the dryer, and a heat exchanger or a heater to directly provide heat to the dryer. This system not only provides a very efficient heat transfer system but results in a minimum carry-over of ultrafine particles thereby eliminating any explosive hazard.

Decarboxylation Study of Acidic Cannabinoids: A Novel Approach Using Ultra-High-Performance Supercritical Fluid Chromatography/Photodiode Array-Mass Spectrometry

PubMed Central

Wang, Mei; Wang, Yan-Hong; Avula, Bharathi; Radwan, Mohamed M.; Wanas, Amira S.; van Antwerp, John; Parcher, Jon F.; ElSohly, Mahmoud A.; Khan, Ikhlas A.

2016-01-01

Abstract Introduction: Decarboxylation is an important step for efficient production of the major active components in cannabis, for example, Δ9-tetrahydrocannabinol (Δ9-THC), cannabidiol (CBD), and cannabigerol (CBG). These cannabinoids do not occur in significant concentrations in cannabis but can be formed by decarboxylation of their corresponding acids, the predominant cannabinoids in the plant. Study of the kinetics of decarboxylation is of importance for phytocannabinoid isolation and dosage formulation for medical use. Efficient analytical methods are essential for simultaneous detection of both neutral and acidic cannabinoids. Methods: C. sativa extracts were used for the studies. Decarboxylation conditions were examined at 80°C, 95°C, 110°C, 130°C, and 145°C for different times up to 60 min in a vacuum oven. An ultra-high performance supercritical fluid chromatography/photodiode array-mass spectrometry (UHPSFC/PDA-MS) method was used for the analysis of acidic and neutral cannabinoids before and after decarboxylation. Results: Decarboxylation at different temperatures displayed an exponential relationship between concentration and time indicating a first-order or pseudo-first-order reaction. The rate constants for Δ9-tetrahydrocannabinolic acid-A (THCA-A) were twice those of the cannabidiolic acid (CBDA) and cannabigerolic acid (CBGA). Decarboxylation of THCA-A was forthright with no side reactions or by-products. Decarboxylation of CBDA and CBGA was not as straightforward due to the unexplained loss of reactants or products. Conclusion: The reported UHPSFC/PDA-MS method provided consistent and sensitive analysis of phytocannabinoids and their decarboxylation products and degradants. The rate of change of acidic cannabinoid concentrations over time allowed for determination of rate constants. Variations of rate constants with temperature yielded values for reaction energy. PMID:28861498

Supercritical impregnation and optical characterization of loaded foldable intraocular lenses using supercritical fluids.

PubMed

Bouledjouidja, Abir; Masmoudi, Yasmine; Li, Yanfeng; He, Wei; Badens, Elisabeth

2017-10-01

To prepare drug-loaded intraocular lenses (IOLs) used to combine cataract surgery with postoperative complication treatment through supercritical impregnation while preserving their optical properties. Aix-Marseille Université, CNRS, Centrale Marseille, Laboratoire de Mécanique, Modélisation & Procédés Propres, Marseille, France, and He University Eye Hospital, Liaoning Province, China. Experimental study. Supercritical impregnations of commercial foldable IOLs used in cataract surgery with ciprofloxacin (an antibiotic) and dexamethasone 21-phosphate disodium salt (an antiinflammatory drug) were performed in a noncontinuous mode. Impregnation amounts were determined through drug-release kinetic studies. The optical characterizations of IOLs were determined by evaluating the dioptric power and the imaging quality by determining the modulating transfer function (MTF) at a specified spatial frequency according to the International Organization for Standardization (ISO 11979-2:2014). Transparent IOLs presenting an effective impregnation were obtained with a prolonged drug delivery during approximately 10 days. Optical characterizations (dioptric powers and MTF values) show preserved optical properties after supercritical treatment/impregnation. Supercritical treatments/impregnations do not damage the optical properties of IOLs and are therefore adequate for the preparation of delivery devices used for cataract surgery. Copyright © 2017. Published by Elsevier Inc.

Effects of supercritical environment on hydrocarbon-fuel injection

NASA Astrophysics Data System (ADS)

Shin, Bongchul; Kim, Dohun; Son, Min; Koo, Jaye

2017-04-01

In this study, the effects of environment conditions on decane were investigated. Decane was injected in subcritical and supercritical ambient conditions. The visualization chamber was pressurized to 1.68 MPa by using nitrogen gas at a temperature of 653 K for subcritical ambient conditions. For supercritical ambient conditions, the visualization chamber was pressurized to 2.52 MPa by using helium at a temperature of 653 K. The decane injection in the pressurized chamber was visualized via a shadowgraph technique and gradient images were obtained by a post processing method. A large variation in density gradient was observed at jet interface in the case of subcritical injection in subcritical ambient conditions. Conversely, for supercritical injection in supercritical ambient conditions, a small density gradient was observed at the jet interface. In a manner similar to that observed in other cases, supercritical injection in subcritical ambient conditions differed from supercritical ambient conditions such as sphere shape liquid. Additionally, there were changes in the interface, and the supercritical injection core width was thicker than that in the subcritical injection. Furthermore, in cases with the same injection conditions, the change in the supercritical ambient normalized core width was smaller than the change in the subcritical ambient normalized core width owing to high specific heat at the supercritical injection and small phase change at the interface. Therefore, the interface was affected by the changing ambient condition. Given that the effect of changing the thermodynamic properties of propellants could be essential for a variable thrust rocket engine, the effects of the ambient conditions were investigated experimentally.

Geothermal energy production with supercritical fluids

DOEpatents

Brown, Donald W.

2003-12-30

There has been invented a method for producing geothermal energy using supercritical fluids for creation of the underground reservoir, production of the geothermal energy, and for heat transport. Underground reservoirs are created by pumping a supercritical fluid such as carbon dioxide into a formation to fracture the rock. Once the reservoir is formed, the same supercritical fluid is allowed to heat up and expand, then is pumped out of the reservoir to transfer the heat to a surface power generating plant or other application.

Dynamics of Supercritical Flows

DTIC Science & Technology

2012-08-26

to Supercritical Environment of Relevance to Rocket, Gas turbine , and Diesel Engines,” 37th AIAA Aerospace Science Meeting and Exhibit, AIAA...Visual Characteristics of a Round Jet into a Sub- to Supercritical Environment of Relevance to Rocket, Gas turbine , and Diesel Engines,” 37th AIAA...Relevance to Rocket, Gas turbine , and Diesel Engines,” 37th AIAA Aerospace Science Meeting and Exhibit, AIAA, Washington, DC, 11-14 Jan. 1999. 26Chehroudi

Enhancing power cycle efficiency for a supercritical Brayton cycle power system using tunable supercritical gas mixtures

DOEpatents

Wright, Steven A.; Pickard, Paul S.; Vernon, Milton E.; Radel, Ross F.

2017-08-29

Various technologies pertaining to tuning composition of a fluid mixture in a supercritical Brayton cycle power generation system are described herein. Compounds, such as Alkanes, are selectively added or removed from an operating fluid of the supercritical Brayton cycle power generation system to cause the critical temperature of the fluid to move up or down, depending upon environmental conditions. As efficiency of the supercritical Brayton cycle power generation system is substantially optimized when heat is rejected near the critical temperature of the fluid, dynamically modifying the critical temperature of the fluid based upon sensed environmental conditions improves efficiency of such a system.

Supercritical methanol for polyethylene terephthalate depolymerization: Observation using simulator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Genta, Minoru; Iwaya, Tomoko; Sasaki, Mitsuru

2007-07-01

To apply PET depolymerization in supercritical methanol to commercial recycling, the benefits of supercritical methanol usage in PET depolymerization was investigated from the viewpoint of the reaction rate and energy demands. PET was depolymerized in a batch reactor at 573 K in supercritical methanol under 14.7 MPa and in vapor methanol under 0.98 MPa in our previous work. The main products of both reactions were the PET monomers of dimethyl terephthalate (DMT) and ethylene glycol (EG). The rate of PET depolymerization in supercritical methanol was faster than that of PET depolymerization in vapor methanol. This indicates supercritical fluid is beneficialmore » in reducing reaction time without the use of a catalyst. We depicted the simple process flow of PET depolymerization in supercritical methanol and in vapor methanol, and by simulation evaluated the total heat demand of each process. In this simulation, bis-hydroxyethyl terephthalate (BHET) was used as a model component of PET. The total heat demand of PET depolymerization in supercritical methanol was 2.35 x 10{sup 6} kJ/kmol Produced-DMT. That of PET depolymerization in vapor methanol was 2.84 x 10{sup 6} kJ/kmol Produced-DMT. The smaller total heat demand of PET depolymerization in supercritical methanol clearly reveals the advantage of using supercritical fluid in terms of energy savings.« less

Supercritical Fluids Processing of Biomass to Chemicals and Fuels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olson, Norman K.

2011-09-28

The main objective of this project is to develop and/or enhance cost-effective methodologies for converting biomass into a wide variety of chemicals, fuels, and products using supercritical fluids. Supercritical fluids will be used both to perform reactions of biomass to chemicals and products as well as to perform extractions/separations of bio-based chemicals from non-homogeneous mixtures. This work supports the Biomass Program’s Thermochemical Platform Goals. Supercritical fluids are a thermochemical approach to processing biomass that, while aligned with the Biomass Program’s interests in gasification and pyrolysis, offer the potential for more precise and controllable reactions. Indeed, the literature with respect tomore » the use of water as a supercritical fluid frequently refers to “supercritical water gasification” or “supercritical water pyrolysis.”« less

Bio-oil production from biomass via supercritical fluid extraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Durak, Halil, E-mail: halildurak@yyu.edu.tr

2016-04-18

Supercritical fluid extraction is used for producing bio-fuel from biomass. Supercritical fluid extraction process under supercritical conditions is the thermally disruption process of the lignocellulose or other organic materials at 250-400 °C temperature range under high pressure (4-5 MPa). Supercritical fluid extraction trials were performed in a cylindrical reactor (75 mL) in organic solvents (acetone, ethanol) under supercritical conditions with (calcium hydroxide, sodium carbonate) and without catalyst at the temperatures of 250, 275 and 300 °C. The produced liquids at 300 °C in supercritical liquefaction were analyzed and characterized by elemental, GC-MS and FT-IR. 36 and 37 different types of compounds weremore » identified by GC-MS obtained in acetone and ethanol respectively.« less

Using supercritical fluids to refine hydrocarbons

DOEpatents

Yarbro, Stephen Lee

2015-06-09

A system and method for reactively refining hydrocarbons, such as heavy oils with API gravities of less than 20 degrees and bitumen-like hydrocarbons with viscosities greater than 1000 cp at standard temperature and pressure, using a selected fluid at supercritical conditions. A reaction portion of the system and method delivers lightweight, volatile hydrocarbons to an associated contacting unit which operates in mixed subcritical/supercritical or supercritical modes. Using thermal diffusion, multiphase contact, or a momentum generating pressure gradient, the contacting unit separates the reaction products into portions that are viable for use or sale without further conventional refining and hydro-processing techniques.

Direct energy recovery from primary and secondary sludges by supercritical water oxidation.

PubMed

Svanström, M; Modell, M; Tester, J

2004-01-01

Supercritical water oxidation (SCWO) oxidizes organic and biological materials virtually completely to benign products without the need for stack gas scrubbing. Heavy metals are recovered as stabilized solid, along with the sand and clay that is present in the feed. The technology has been under development for twenty years. The major obstacle to commercialization has been developing reactors that are not clogged by inorganic solid deposits. That problem has been solved by using tubular reactors with fluid velocities that are high enough to keep solids in suspension. Recently, system designs have been created that reduce the cost of processing sewage sludges below that of incineration. At 10 wt- % dry solids, sludge can be oxidized with virtually complete recovery of the sludge heating value as hot water or high-pressure steam. Liquid carbon dioxide of high purity can be recovered from the gaseous effluent and excess oxygen can be recovered for recycle. The net effect is to reduce the stack to a harmless vent with minimal flow rate of a clean gas. Complete simulations have been developed using physical property models that accurately simulate the thermodynamic properties of sub- and supercritical water in mixtures with O2, N2, CO2, and organics. Capital and operating cost estimates are given for sewage sludge treatment, which are less costly than incineration. The scenario of direct recovery of energy from sludges has inherent benefits compared to other gasification or liquefaction options.

Ultra-high performance supercritical fluid chromatography-mass spectrometry procedure for analysis of monosaccharides from plant gum binders.

PubMed

Pauk, Volodymyr; Pluháček, Tomáš; Havlíček, Vladimír; Lemr, Karel

2017-10-09

The ultra-high performance supercritical fluid chromatography-mass spectrometry (UHPSFC/MS) procedure for analysis of native monosaccharides was developed. Chromatographic conditions were investigated to separate a mixture of four hexoses, three pentoses, two deoxyhexoses and two uronic acids. Increasing water content in methanol modifier to 5% and formic acid to 4% improved peak shapes of neutral monosaccharides and allowed complete elution of highly polar uronic acids in a single run. An Acquity HSS C18SB column outperformed other three tested stationary phases (BEH (silica), BEH 2-ethylpyridine, CSH Fluoro-Phenyl) in terms of separation of isomers and analysis time (4.5 min). Limits of detection were in the range 0.01-0.12 ng μL -1 . Owing to separation of anomers, identification of critical pairs (arabinose-xylose and glucose-galactose) was possible. Feasibility of the new method was demonstrated on plant-derived polysaccharide binders. Samples of watercolor paints, painted paper and three plant gums widely encountered in painting media (Arabic, cherry and tragacanth) were decomposed prior the analysis by microwave-assisted hydrolysis at 40 bar initial pressure using 2 mol L -1 trifluoroacetic acid. Among tested temperatures, 120 °C ensured appropriate hydrolysis efficiency for different types of gum and avoided excessive degradation of labile monosaccharides. Procedure recovery tested on gum Arabic was 101% with an RSD below 8%. Aqueous hydrolysates containing monosaccharides in different ratios specific to each type of plant gum were diluted or analyzed directly. Filtration of samples before hydrolysis reduced interferences from a paper support and identification of gum Arabic in watercolor-painted paper samples was demonstrated. Successful identification of pure gum Arabic was confirmed for sample quantities as little as 1 μg. Two classification approaches were compared and principal component analysis was superior to analysis based on peak area

4. STEAM PLANT MARINE BOILERS WEST OF STEAM PLANT AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. STEAM PLANT MARINE BOILERS WEST OF STEAM PLANT AND SOUTH OF ORIGINAL STEAM PLANT BOILERS, FROM SOUTH. November 13, 1990 - Crosscut Steam Plant, North side Salt River near Mill Avenue & Washington Street, Tempe, Maricopa County, AZ

Conceptual design of a thermalhydraulic loop for multiple test geometries at supercritical conditions named Supercritical Phenomena Experimental Test Apparatus (SPETA)

NASA Astrophysics Data System (ADS)

Adenariwo, Adepoju

The efficiency of nuclear reactors can be improved by increasing the operating pressure of current nuclear reactors. Current CANDU-type nuclear reactors use heavy water as coolant at an outlet pressure of up to 11.5 MPa. Conceptual SuperCritical Water Reactors (SCWRs) will operate at a higher coolant outlet pressure of 25 MPa. Supercritical water technology has been used in advanced coal plants and its application proves promising to be employed in nuclear reactors. To better understand how supercritical water technology can be applied in nuclear power plants, supercritical water loops are used to study the heat transfer phenomena as it applies to CANDU-type reactors. A conceptual design of a loop known as the Supercritical Phenomena Experimental Apparatus (SPETA) has been done. This loop has been designed to fit in a 9 m by 2 m by 2.8 m enclosure that will be installed at the University of Ontario Institute of Technology Energy Research Laboratory. The loop include components to safely start up and shut down various test sections, produce a heat source to the test section, and to remove reject heat. It is expected that loop will be able to investigate the behaviour of supercritical water in various geometries including bare tubes, annulus tubes, and multi-element-type bundles. The experimental geometries are designed to match the fluid properties of Canadian SCWR fuel channel designs so that they are representative of a practical application of supercritical water technology in nuclear plants. This loop will investigate various test section orientations which are the horizontal, vertical, and inclined to investigate buoyancy effects. Frictional pressure drop effects and satisfactory methods of estimating hydraulic resistances in supercritical fluid shall also be estimated with the loop. Operating limits for SPETA have been established to be able to capture the important heat transfer phenomena at supercritical conditions. Heat balance and flow calculations have

Anomalous sorption of supercritical fluids on polymer thin films.

PubMed

Wang, Xiaochu; Sanchez, Isaac C

2006-10-24

Unusual sorption has been reported in thin polymer films exposed to near-critical CO2. When the supercritical fluid approaches the critical point, the film appears to thicken, but it is not clear whether the film swells or there is an adsorption layer on the film surface. A combination of the gradient theory of inhomogeneous systems and the Sanchez-Lacombe equation of state has been used to investigate this phenomenon. It is shown analytically that surface adsorption on an attractive surface is proportional to the compressibility of the fluid. We have also investigated numerically the sorption of supercritical CO2 on poly(dimethylsiloxane) and polyisobutylene, and supercritical 1,1-difluoroethane on polystyrene. By calculating the Gibbs adsorption and adsorption layer thickness of the supercritical fluids, we found in all cases (different substrates, different supercritical fluids) that maximum adsorption occurs when the supercritical fluid is near its compressibility maximum.

The influence of ultra-pasteurization by indirect heating versus direct steam injection on skim and 2% fat milks.

PubMed

Lee, A P; Barbano, D M; Drake, M A

2017-03-01

Fluid milk is traditionally pasteurized by high temperature, short time (HTST) pasteurization, which requires heating to at least 72°C for 15 s. Ultra-pasteurization (UP) extends milk shelf life and is defined as heating to at least 138°C for 2 s. The UP process can be done by indirect heating (IND) or by direct steam injection (DSI). The influence of these 2 UP methods on milk flavor has not been widely investigated. The objective of this study was to compare the effect of HTST, IND-UP, and DSI-UP on sensory perception of fluid milk. Raw skim and standardized 2% milks were pasteurized at 140°C for 2.3 s by IND or DSI or by HTST (78°C, 15 s) and homogenized at 20.7 MPa. The processed milks were stored in light-shielded opaque high-density polyethylene containers at 4°C and examined by descriptive analysis and microbial analysis on d 3, 7, and 14. Furosine and serum protein denaturation analyses were performed on d 0 and 14 as an indicator of heat treatment. Last, consumer acceptance testing was conducted at d 10, with adults (n = 250) and children (ages 8 to13 y, n = 100) who were self-reported consumers of skim or 2% milk; consumers only received samples for either skim or 2% milk. The entire experiment was repeated in triplicate. Milks treated by HTST had lower cooked flavor than either UP milk. Milks heated by DSI-UP were characterized by sulfur or eggy and cooked flavors, whereas IND-UP milks had higher sweet aromatic and sweet taste compared with DSI-UP milk. Aromatic flavor intensities of all milks decreased across 14 d of storage. Furosine concentrations and serum protein denaturation were highest for the IND treatments, followed by DSI and HTST. Furosine content in both skim and 2% milk increased with time, but the increase was faster in IND-UP skim milk. Adult and child consumers preferred HTST milk over either UP milk, regardless of fat content. Ultra-pasteurization by IND or DSI did not affect consumer acceptance at 10 d postprocessing, but

Supercritical fuel injection system

NASA Technical Reports Server (NTRS)

Marek, C. J.; Cooper, L. P. (Inventor)

1980-01-01

a fuel injection system for gas turbines is described including a pair of high pressure pumps. The pumps provide fuel and a carrier fluid such as air at pressures above the critical pressure of the fuel. A supercritical mixing chamber mixes the fuel and carrier fluid and the mixture is sprayed into a combustion chamber. The use of fuel and a carrier fluid at supercritical pressures promotes rapid mixing of the fuel in the combustion chamber so as to reduce the formation of pollutants and promote cleaner burning.

Exfoliation Propensity of Oxide Scale in Heat Exchangers Used for Supercritical CO2 Power Cycles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sabau, Adrian S; Shingledecker, John P.; Kung, Steve

2016-01-01

Supercritical CO2 (sCO2) Brayton cycle systems offer the possibility of improved efficiency in future fossil energy power generation plants operating at temperatures of 650 C and above. As there are few data on the oxidation/corrosion behavior of structural alloys in sCO2 at these temperatures, modeling to predict the propensity for oxide exfoliation is not well developed, thus hindering materials selection for these novel cycles. The ultimate goal of this effort is to provide needed data on scale exfoliation behavior in sCO2 for confident alloy selection. To date, a model developed by ORNL and EPRI for the exfoliation of oxide scalesmore » formed on boiler tubes in high-temperature, high-pressure steam has proven useful for managing exfoliation in conventional steam plants. A major input provided by the model is the ability to predict the likelihood of scale failure and loss based on understanding of the evolution of the oxide morphologies and the conditions that result in susceptibility to exfoliation. This paper describes initial steps taken to extend the existing model for exfoliation of steam-side oxide scales to sCO2 conditions. The main differences between high-temperature, high-pressure steam and sCO2 that impact the model involve (i) significant geometrical differences in the heat exchangers, ranging from standard pressurized tubes seen typically in steam-producing boilers to designs for sCO2 that employ variously-curved thin walls to create shaped flow paths for extended heat transfer area and small channel cross-sections to promote thermal convection and support pressure loads; (ii) changed operating characteristics with sCO2 due to the differences in physical and thermal properties compared to steam; and (iii) possible modification of the scale morphologies, hence properties that influence exfoliation behavior, due to reaction with carbon species from sCO2. The numerical simulations conducted were based on an assumed sCO2 operating schedule and

Supercritical fluid technology: concepts and pharmaceutical applications.

PubMed

Deshpande, Praful Balavant; Kumar, G Aravind; Kumar, Averineni Ranjith; Shavi, Gopal Venkatesh; Karthik, Arumugam; Reddy, Meka Sreenivasa; Udupa, Nayanabhirama

2011-01-01

In light of environmental apprehension, supercritical fluid technology (SFT) exhibits excellent opportunities to accomplish key objectives in the drug delivery sector. Supercritical fluid extraction using carbon dioxide (CO(2)) has been recognized as a green technology. It is a clean and versatile solvent with gas-like diffusivity and liquid-like density in the supercritical phase, which has provided an excellent alternative to the use of chemical solvents. The present commentary provides an overview of different techniques using supercritical fluids and their future opportunity for the drug delivery industry. Some of the emerging applications of SFT in pharmaceuticals, such as particle design, drug solubilization, inclusion complex, polymer impregnation, polymorphism, drug extraction process, and analysis, are also covered in this review. The data collection methods are based on the recent literature related to drug delivery systems using SFT platforms. SFT has become a much more versatile and environmentally attractive technology that can handle a variety of complicated problems in pharmaceuticals. This cutting-edge technology is growing predominantly to surrogate conventional unit operations in relevance to the pharmaceutical production process. Supercritical fluid technology has recently drawn attention in the field of pharmaceuticals. It is a distinct conception that utilizes the solvent properties of supercritical fluids above their critical temperature and pressure, where they exhibit both liquid-like and gas-like properties, which can enable many pharmaceutical applications. For example, the liquid-like properties provide benefits in extraction processes of organic solvents or impurities, drug solubilization, and polymer plasticization, and the gas-like features facilitate mass transfer processes. It has become a much more versatile and environmentally attractive technology that can handle a variety of complicated problems in pharmaceuticals. This review is

General corrosion properties of modified PNC1520 austenitic stainless steel in supercritical water as a fuel cladding candidate material for supercritical water reactor

NASA Astrophysics Data System (ADS)

Nakazono, Y.; Iwai, T.; Abe, H.

2010-03-01

The Super-Critical Water-cooled Reactor (SCWR) has been designed and investigated because of its high thermal efficiency and plant simplification. There are some advantages including the use of a single phase coolant with high enthalpy but there are numerous potential problems, particularly with materials. As the operating temperature of supercritical water reactor will be between 280°C and 620°C with a pressure of 25MPa, the selection of materials is difficult and important. Austenitic stainless steels were selected for possible use in supercritical water systems because of their corrosion resistance and radiation resistance. The PNC1520 austenitic stainless steel developed by Japan Atomic Energy Agency (JAEA) as a nuclear fuel cladding material for a Na-cooled fast breeder reactor. The corrosion data of PNC1520 in supercritical water (SCW) is required but does not exist. The purpose of the present study is to research the corrosion properties for PNC1520 austenitic stainless steel in supercritical water. The supercritical water corrosion test was performed for the standard PNC1520 (1520S) and the Ti-additional type of PNC1520 (1520Ti) by using a supercritical water autoclave. Corrosion tests on the austenitic 1520S and 1520Ti steels in supercritical water were performed at 400, 500 and 600°C with exposures up to 1000h. The amount of weight gain, weight loss and weight of scale were evaluated after the corrosion test in supercritical water for both austenitic steels. After 1000h corrosion test performed, the weight gains of both austenitic stainless steels were less than 2 g/m2 at 400°C and 500°C . But both weight gain and weight loss of 1520Ti were larger than those of 1520S at 600°C . By increasing the temperature to 600°C, the surface of 1520Ti was covered with magnetite formed in supercritical water and dissolution of the steel alloying elements has been observed. In view of corrosion, 1520S may have larger possibility than 1520Ti to adopt a

On-line coupling of supercritical fluid extraction and chromatographic techniques.

PubMed

Sánchez-Camargo, Andrea Del Pilar; Parada-Alfonso, Fabián; Ibáñez, Elena; Cifuentes, Alejandro

2017-01-01

This review summarizes and discusses recent advances and applications of on-line supercritical fluid extraction coupled to liquid chromatography, gas chromatography, and supercritical fluid chromatographic techniques. Supercritical fluids, due to their exceptional physical properties, provide unique opportunities not only during the extraction step but also in the separation process. Although supercritical fluid extraction is especially suitable for recovery of non-polar organic compounds, this technique can also be successfully applied to the extraction of polar analytes by the aid of modifiers. Supercritical fluid extraction process can be performed following "off-line" or "on-line" approaches and their main features are contrasted herein. Besides, the parameters affecting the supercritical fluid extraction process are explained and a "decision tree" is for the first time presented in this review work as a guide tool for method development. The general principles (instrumental and methodological) of the different on-line couplings of supercritical fluid extraction with chromatographic techniques are described. Advantages and shortcomings of supercritical fluid extraction as hyphenated technique are discussed. Besides, an update of the most recent applications (from 2005 up to now) of the mentioned couplings is also presented in this review. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Theoretical models for supercritical fluid extraction.

PubMed

Huang, Zhen; Shi, Xiao-Han; Jiang, Wei-Juan

2012-08-10

For the proper design of supercritical fluid extraction processes, it is essential to have a sound knowledge of the mass transfer mechanism of the extraction process and the appropriate mathematical representation. In this paper, the advances and applications of kinetic models for describing supercritical fluid extraction from various solid matrices have been presented. The theoretical models overviewed here include the hot ball diffusion, broken and intact cell, shrinking core and some relatively simple models. Mathematical representations of these models have been in detail interpreted as well as their assumptions, parameter identifications and application examples. Extraction process of the analyte solute from the solid matrix by means of supercritical fluid includes the dissolution of the analyte from the solid, the analyte diffusion in the matrix and its transport to the bulk supercritical fluid. Mechanisms involved in a mass transfer model are discussed in terms of external mass transfer resistance, internal mass transfer resistance, solute-solid interactions and axial dispersion. The correlations of the external mass transfer coefficient and axial dispersion coefficient with certain dimensionless numbers are also discussed. Among these models, the broken and intact cell model seems to be the most relevant mathematical model as it is able to provide realistic description of the plant material structure for better understanding the mass-transfer kinetics and thus it has been widely employed for modeling supercritical fluid extraction of natural matters. Copyright © 2012 Elsevier B.V. All rights reserved.

Development of Ultra-high Purity (UHP) Fe-Based Alloys with High Creep and Oxidation Resistance for A-USC Technology

NASA Astrophysics Data System (ADS)

Hamdani, Fethi; Das, Nishith K.; Shoji, Tetsuo

2018-06-01

The design of ultra-high purity (UHP) Fe-based model alloys for advanced ultra-supercritical (A-USC) technology is attempted in this work. Creep testing has been performed in air at 700 °C and a stress level of 150 MPa. Analysis of the fracture surface and cross section of the crept specimen was performed. To evaluate the oxidation resistance in A-USC conditions, oxidation testing was performed in supercritical water (SCW) at 700 °C and 25 MPa. Weight gain (WG) measurements and meticulous characterization of the oxide scale were carried out. Based on thermodynamics and density functional theory calculations, some reactive elements in the Fe-Cr-Ni system were designated to promote precipitation strengthening and to improve the hydrogen-accelerated oxidation resistance. The addition of a 2 wt pct Mo into Fe-22Cr-22Ni-0.6Nb wt pct-based matrix did not significantly improve the creep resistance. The addition of 0.26 wt pct Zr coupled with cold working was effective for improving creep properties. The Mo-modified model alloy showed almost the same WG value as SUS310, while the Zr-modified alloy showed a higher WG value. Meanwhile, a Cr-enriched continuous oxide layer was formed at the oxidation front of the Zr-modified alloy and SUS310S after exposure to SCW conditions.

Development of Ultra-high Purity (UHP) Fe-Based Alloys with High Creep and Oxidation Resistance for A-USC Technology

NASA Astrophysics Data System (ADS)

Hamdani, Fethi; Das, Nishith K.; Shoji, Tetsuo

2018-03-01

The design of ultra-high purity (UHP) Fe-based model alloys for advanced ultra-supercritical (A-USC) technology is attempted in this work. Creep testing has been performed in air at 700 °C and a stress level of 150 MPa. Analysis of the fracture surface and cross section of the crept specimen was performed. To evaluate the oxidation resistance in A-USC conditions, oxidation testing was performed in supercritical water (SCW) at 700 °C and 25 MPa. Weight gain (WG) measurements and meticulous characterization of the oxide scale were carried out. Based on thermodynamics and density functional theory calculations, some reactive elements in the Fe-Cr-Ni system were designated to promote precipitation strengthening and to improve the hydrogen-accelerated oxidation resistance. The addition of a 2 wt pct Mo into Fe-22Cr-22Ni-0.6Nb wt pct-based matrix did not significantly improve the creep resistance. The addition of 0.26 wt pct Zr coupled with cold working was effective for improving creep properties. The Mo-modified model alloy showed almost the same WG value as SUS310, while the Zr-modified alloy showed a higher WG value. Meanwhile, a Cr-enriched continuous oxide layer was formed at the oxidation front of the Zr-modified alloy and SUS310S after exposure to SCW conditions.

Supercritical water oxidation of products of human metabolism

NASA Technical Reports Server (NTRS)

Tester, Jefferson W.; Orge A. achelling, Richard K. ADTHOMASSON; Orge A. achelling, Richard K. ADTHOMASSON

1986-01-01

Although the efficient destruction of organic material was demonstrated in the supercritical water oxidation process, the reaction kinetics and mechanisms are unknown. The kinetics and mechanisms of carbon monoxide and ammonia oxidation in and reaction with supercritical water were studied experimentally. Experimental oxidation of urine and feces in a microprocessor controlled system was performed. A minaturized supercritical water oxidation process for space applications was design, including preliminary mass and energy balances, power, space and weight requirements.

Advanced Supercritical Carbon Dioxide Brayton Cycle Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, Mark; Sienicki, James; Moisseytsev, Anton

2015-10-21

Fluids operating in the supercritical state have promising characteristics for future high efficiency power cycles. In order to develop power cycles using supercritical fluids, it is necessary to understand the flow characteristics of fluids under both supercritical and two-phase conditions. In this study, a Computational Fluid Dynamic (CFD) methodology was developed for supercritical fluids flowing through complex geometries. A real fluid property module was implemented to provide properties for different supercritical fluids. However, in each simulation case, there is only one species of fluid. As a result, the fluid property module provides properties for either supercritical CO 2 (S-CO 2)more » or supercritical water (SCW). The Homogeneous Equilibrium Model (HEM) was employed to model the two-phase flow. HEM assumes two phases have same velocity, pressure, and temperature, making it only applicable for the dilute dispersed two-phase flow situation. Three example geometries, including orifices, labyrinth seals, and valves, were used to validate this methodology with experimental data. For the first geometry, S-CO 2 and SCW flowing through orifices were simulated and compared with experimental data. The maximum difference between the mass flow rate predictions and experimental measurements is less than 5%. This is a significant improvement as previous works can only guarantee 10% error. In this research, several efforts were made to help this improvement. First, an accurate real fluid module was used to provide properties. Second, the upstream condition was determined by pressure and density, which determines supercritical states more precise than using pressure and temperature. For the second geometry, the flow through labyrinth seals was studied. After a successful validation, parametric studies were performed to study geometric effects on the leakage rate. Based on these parametric studies, an optimum design strategy for the see-through labyrinth seals was

Nested subcritical flows within supercritical systems

NASA Technical Reports Server (NTRS)

Hendricks, R. C.; Braun, M. J.; Wheeler, R. L., III; Mullen, R. L.

1985-01-01

In supercritical systems the design inlet and outlet pressures are maintained above the thermaodynamic critical pressure P sub C. Designers rely on this simple rule of thumb to circumvent problems associated with a subcritical pressure regime nested within the supercritical pressure system along with the uncertainties in heat transfer, fluid mechanics, and thermophysical property variations. The simple rule of thumb is adequate in many low-power designs but is inadequate for high-performance turbomachines and linear systems, where nested two-phase regions can exist. Examples for a free-jet expansion with backpressure greater than P sub C and a rotor (bearing) with ambient pressure greater than P sub C illustrate the existence of subcritical pressure regimes nested within supercritical systems.

8. TURBINE DECK (UPPER FLOOR) INSIDE STEAM PLANT, SHOWING STEAM ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. TURBINE DECK (UPPER FLOOR) INSIDE STEAM PLANT, SHOWING STEAM TURBINES AND GENERATORS, LOOKING NORTH. November 13, 1990 - Crosscut Steam Plant, North side Salt River near Mill Avenue & Washington Street, Tempe, Maricopa County, AZ

Effects of supercritical carbon dioxide sterilization on polysaccharidic membranes for surgical applications.

PubMed

Scognamiglio, F; Blanchy, M; Borgogna, M; Travan, A; Donati, I; Bosmans, J W A M; Foulc, M P; Bouvy, N D; Paoletti, S; Marsich, E

2017-10-01

Sterilization methods such as ɣ-irradiation, steam sterilization and ethylene oxide gas treatment can have negative effects on molecular structure and properties of polysaccharide-based biomaterials. In this perspective, the use of supercritical carbon dioxide (scCO 2 ) has been proposed as an alternative method for biomaterial sterilization. In this work, chemical, mechanical and biological properties of polysaccharidic membranes for surgical applications were investigated after sterilization by scCO 2 . Four sets of sterilizing conditions were considered and SEC analyses were performed in order to identify the one with lower impact on the polysaccharidic matrix of membranes (alginate). Mechanical tests showed that the resistance of membranes was slightly affected after sterilization. Biological analyses proved the biocompatibility of the sterilized membranes both in vitro and in a preliminary in vivo test. Overall, this study points out that this sterilization technique can be successfully employed to achieve an effective and safe sterilization of polysaccharidic membranes for surgical use. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of supercritical carbon dioxide decaffeination on volatile components of green teas.

PubMed

Lee, S; Park, M K; Kim, K H; Kim, Y-S

2007-09-01

Volatile components in regular and decaffeinated green teas were isolated by simultaneous steam distillation and solvent extraction (SDE), and then analyzed by GC-MS. A total of 41 compounds, including 8 alcohols, 15 terpene-type compounds, 10 carbonyls, 4 N-containing compounds, and 4 miscellaneous compounds, were found in regular and decaffeinated green teas. Among them, linalool and phenylacetaldehyde were quantitatively dominant in both regular and decaffeinated green teas. By a decaffeination process using supercritical carbon dioxide, most volatile components decreased. The more caffeine was removed, the more volatile components were reduced in green teas. In particular, relatively nonpolar components such as terpene-type compounds gradually decreased according to the decaffeination process. Aroma-active compounds in regular and decaffeinated green teas were also determined and compared by aroma extract dilution analysis (AEDA). Most greenish and floral flavor compounds such as hexanal, (E)-2-hexenal, and some unknown compounds disappeared or decreased after the decaffeination process.

Optimization of power-cycle arrangements for Supercritical Water cooled Reactors (SCWRs)

NASA Astrophysics Data System (ADS)

Lizon-A-Lugrin, Laure

The world energy demand is continuously rising due to the increase of both the world population and the standard of life quality. Further, to assure both a healthy world economy as well as adequate social standards, in a relatively short term, new energy-conversion technologies are mandatory. Within this framework, a Generation IV International Forum (GIF) was established by the participation of 10 countries to collaborate for developing nuclear power reactors that will replace the present technology by 2030. The main goals of these nuclear-power reactors are: economic competitiveness, sustainability, safety, reliability and resistance to proliferation. As a member of the GIF, Canada has decided to orient its efforts towards the design of a CANDU-type Super Critical Water-cooled Reactor (SCWR). Such a system must run at a coolant outlet temperature of about 625°C and at a pressure of 25 MPa. It is obvious that at such conditions the overall efficiency of this kind of Nuclear Power Plant (NPP) will compete with actual supercritical water-power boilers. In addition, from a heat-transfer viewpoint, the use of a supercritical fluid allows the limitation imposed by Critical Heat Flux (CHF) conditions, which characterize actual technologies, to be removed. Furthermore, it will be also possible to use direct thermodynamic cycles where the supercritical fluid expands right away in a turbine without the necessity of using intermediate steam generators and/or separators. This work presents several thermodynamic cycles that could be appropriate to run SCWR power plants. Improving both thermal efficiency and mechanical power constitutes a multi-objective optimization problem and requires specific tools. To this aim, an efficient and robust evolutionary algorithm, based on genetic algorithm, is used and coupled to an appropriate power plant thermodynamic simulation model. The results provide numerous combinations to achieve a thermal efficiency higher than 50% with a

5. STEAM PLANT COOLING TOWER LOCATED WEST OF STEAM PLANT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. STEAM PLANT COOLING TOWER LOCATED WEST OF STEAM PLANT BUILDING, FROM SOUTH. SHOWS CURRENT LEVEL OF DISREPAIR. December 4, 1990 - Crosscut Steam Plant, North side Salt River near Mill Avenue & Washington Street, Tempe, Maricopa County, AZ

Steam trap monitor

DOEpatents

Ryan, M.J.

1987-05-04

A steam trap monitor positioned downstream of a steam trap in a closed steam system includes a first sensor (a hot finger) for measuring the energy of condensate and a second sensor (a cold finger) for measuring the total energy of condensate and steam in the line. The hot finger includes one or more thermocouples for detecting condensate level and energy, while the cold finger contains a liquid with a lower boiling temperature than that of water. Vapor pressure from the liquid is used to do work such as displacing a piston or bellow in providing an indication of total energy (steam + condensate) of the system. Processing means coupled to and responsive to outputs from the hot and cold fingers subtracts the former from the latter to provide an indication of the presence of steam downstream from the trap indicating that the steam trap is malfunctioning. 2 figs.

Analysis of experimental characteristics of multistage steam-jet electors of steam turbines

NASA Astrophysics Data System (ADS)

Aronson, K. E.; Ryabchikov, A. Yu.; Brodov, Yu. M.; Brezgin, D. V.; Zhelonkin, N. V.; Murmanskii, I. B.

2017-02-01

A series of questions for specification of physical gas dynamics model in flow range of steam-jet unit and ejector computation methodology, as well as functioning peculiarities of intercoolers, was formulated based on analysis of experimental characteristics of multistage team-jet steam turbines. It was established that coefficient defining position of critical cross-section of injected flow depends on characteristics of the "sound tube" zone. Speed of injected flow within this tube may exceed that of sound, and pressure jumps in work-steam decrease at the same time. Characteristics of the "sound tube" define optimal axial sizes of the ejector. According to measurement results, the part of steam condensing in the first-stage coolant constitutes 70-80% of steam amount supplied into coolant and is almost independent of air content in steam. Coolant efficiency depends on steam pressure defined by operation of steam-jet unit of ejector of the next stage after coolant of steam-jet stage, temperature, and condensing water flow. As a rule, steam entering content of steam-air mixture supplied to coolant is overheated with respect to saturation temperature of steam in the mixture. This should be taken into account during coolant computation. Long-term operation causes changes in roughness of walls of the ejector's mixing chamber. The influence of change of wall roughness on ejector characteristic is similar to the influence of reverse pressure of the steam-jet stage. Until some roughness value, injection coefficient of the ejector stage operating in superlimiting regime hardly changed. After reaching critical roughness, the ejector switches to prelimiting operating regime.

Surfactant/Supercritical Fluid Cleaning of Contaminated Substrates

NASA Technical Reports Server (NTRS)

White, Gary L.

1997-01-01

CFC's and halogenated hydrocarbon solvents have been the solvents of choice to degrease and otherwise clean precision metal parts to allow proper function. Recent regulations have, however, rendered most of these solvents unacceptable for these purposes. New processes which are being used or which have been proposed to replace these solvents usually either fail to remove water soluble contaminants or produce significant aqueous wastes which must then be disposed of. In this work, a new method for cleaning surfaces will be investigated. Solubility of typical contaminants such as lubricating greases and phosphatizing bath residues will be studied in several surfactant/supercritical fluid solutions. The effect of temperature, pressure, and the composition of the cleaning mixture on the solubility of oily, polar, and ionic contaminants will be investigated. A reverse micellar solution in a supercritical light hydrocarbon solvent will be used to clean samples of industrial wastes. A reverse micellar solution is one where water is dissolved into a non-polar solvent with the aid of a surfactant. The solution will be capable of dissolving both water-soluble contaminants and oil soluble contaminants. Once the contaminants have been dissolved into the solution they will be separated from the light hydrocarbon and precipitated by a relatively small pressure drop and the supercritical solvent will be available for recycle for reuse. The process will be compared to the efficacy of supercritical CO2 cleaning by attempting to clean the same types of substrates and machining wastes with the same contaminants using supercritical CO2. It is anticipated that the supercritical CO2 process will not be capable of removing ionic residues.

Supercritical synthesis of biodiesel.

PubMed

Bernal, Juana M; Lozano, Pedro; García-Verdugo, Eduardo; Burguete, M Isabel; Sánchez-Gómez, Gregorio; López-López, Gregorio; Pucheault, Mathieu; Vaultier, Michel; Luis, Santiago V

2012-07-23

The synthesis of biodiesel fuel from lipids (vegetable oils and animal fats) has gained in importance as a possible source of renewable non-fossil energy in an attempt to reduce our dependence on petroleum-based fuels. The catalytic processes commonly used for the production of biodiesel fuel present a series of limitations and drawbacks, among them the high energy consumption required for complex purification operations and undesirable side reactions. Supercritical fluid (SCF) technologies offer an interesting alternative to conventional processes for preparing biodiesel. This review highlights the advances, advantages, drawbacks and new tendencies involved in the use of supercritical fluids (SCFs) for biodiesel synthesis.

Downhole steam quality measurement

DOEpatents

Lee, D.O.; Montoya, P.C.; Muir, J.F.; Wayland, J.R. Jr.

1985-06-19

The present invention relates to an empirical electrical method for remote sensing of steam quality utilizing flow-through grids which allow measurement of the electrical properties of a flowing two-phase mixture. The measurement of steam quality in the oil field is important to the efficient application of steam assisted recovery of oil. Because of the increased energy content in higher quality steam it is important to maintain the highest possible steam quality at the injection sandface. The effectiveness of a steaming operation without a measure of steam quality downhole close to the point of injection would be difficult to determine. Therefore, a need exists for the remote sensing of steam quality.

Effect of supercritical fluid density on nanoencapsulated drug particle size using the supercritical antisolvent method.

PubMed

Kalani, Mahshid; Yunus, Robiah

2012-01-01

The reported work demonstrates and discusses the effect of supercritical fluid density (pressure and temperature of supercritical fluid carbon dioxide) on particle size and distribution using the supercritical antisolvent (SAS) method in the purpose of drug encapsulation. In this study, paracetamol was encapsulated inside L-polylactic acid, a semicrystalline polymer, with different process parameters, including pressure and temperature, using the SAS process. The morphology and particle size of the prepared nanoparticles were determined by scanning electron microscopy and transmission electron microscopy. The results revealed that increasing temperature enhanced mean particle size due to the plasticizing effect. Furthermore, increasing pressure enhanced molecular interaction and solubility; thus, particle size was reduced. Transmission electron microscopy images defined the internal structure of nanoparticles. Thermal characteristics of nanoparticles were also investigated via differential scanning calorimetry. Furthermore, X-ray diffraction pattern revealed the changes in crystallinity structure during the SAS process. In vitro drug release analysis determined the sustained release of paracetamol in over 4 weeks.

Effect of supercritical fluid density on nanoencapsulated drug particle size using the supercritical antisolvent method

PubMed Central

Kalani, Mahshid; Yunus, Robiah

2012-01-01

The reported work demonstrates and discusses the effect of supercritical fluid density (pressure and temperature of supercritical fluid carbon dioxide) on particle size and distribution using the supercritical antisolvent (SAS) method in the purpose of drug encapsulation. In this study, paracetamol was encapsulated inside L-polylactic acid, a semicrystalline polymer, with different process parameters, including pressure and temperature, using the SAS process. The morphology and particle size of the prepared nanoparticles were determined by scanning electron microscopy and transmission electron microscopy. The results revealed that increasing temperature enhanced mean particle size due to the plasticizing effect. Furthermore, increasing pressure enhanced molecular interaction and solubility; thus, particle size was reduced. Transmission electron microscopy images defined the internal structure of nanoparticles. Thermal characteristics of nanoparticles were also investigated via differential scanning calorimetry. Furthermore, X-ray diffraction pattern revealed the changes in crystallinity structure during the SAS process. In vitro drug release analysis determined the sustained release of paracetamol in over 4 weeks. PMID:22619552

Study on influence of three kinds of stress on crack propagation in butt welds of spiral coil waterwall for ultra supercritical boiler

NASA Astrophysics Data System (ADS)

Yan, Zhenrong; Si, Jun

2017-09-01

The spiral coil waterwall is the main pressure parts and the core functional components of Ultra Supercritical Boiler. In the process of operation, the spiral coil waterwall is under the combined action of welding residual stress, installation defects stress and working fluid stress, Cracks and crack propagation are easy to occur in butt welds with defects. In view of the early cracks in the butt welds of more T23 water cooled walls, in this paper, the influence of various stresses on the crack propagation in the butt welds of spiral coil waterwall was studied by numerical simulation. Firstly, the welding process of T23 water cooled wall tube was simulated, and the welding residual stress field was obtained. Then,on the basis, put the working medium load on the spiral coil waterwall, the supercoated stress distribution of the welding residual stress and the stress of the working medium is obtained. Considering the bending moment formed by stagger joint which is the most common installation defects, the stress field distribution of butt welds in T23 water-cooled wall tubes was obtained by applying bending moment on the basis of the stress field of the welding residual stress and the working medium stress. The results show that, the welding residual stress is small, the effect of T23 heat treatment after welding to improve the weld quality is not obvious; The working medium load plays a great role in the hoop stress of the water cooled wall tube, and promotes the cracks in the butt welds; The axial stress on the water cooled wall tube produced by the installation defect stress is obvious, the stagger joint, and other installation defects are the main reason of crack propagation of spiral coil waterwall. It is recommended that the control the bending moment resulting from the stagger joint not exceed 756.5 NM.

Numerical Simulation of Hydrothermal Salt Separation Process and Analysis and Cost Estimating of Shipboard Liquid Waste Disposal

DTIC Science & Technology

2007-06-01

possible means to improve a variety of processes: supercritical water in steam Rankine cycles (fossil-fuel powered plants), supercritical carbon ... dioxide and supercritical water in advanced nuclear power plants, and oxidation in supercritical water for use in destroying toxic military wastes and...destruction technologies are installed in a class of ship. Additionally, the properties of one waste water destruction medium, supercritical

On high suppression of NO x and CO emissions in gas-turbine plants with combined gas-and-steam cycles

NASA Astrophysics Data System (ADS)

Ivanov, A. A.; Ermakov, A. N.; Shlyakhov, R. A.

2010-12-01

In this work are given results of analyzing processes of production of nitrogen oxides (NO x ) and afterburning of CO when firing natural gas at combined-cycle gas-turbine plants. It is shown that for suppressing emissions of the said microcomponents it is necessary to lower temperature in hot local zones of the flame in which NOx is formed, and, in so doing, to avoid chilling of cold flame zones that prevents afterburning of CO. The required lowering of the combustion temperature can be provided by combustion of mixtures of methane with steam, with high mixing uniformity that ensures the same and optimum fraction of the steam "ballast" in each microvolume of the flame. In addition to chilling, the steam ballast makes it possible to maintain a fairly high concentration of hydroxil radicals in the flame zone as well, and this provides high burning out of fuel and reduction in carbon monoxide emissions (active steam ballast). Due to this fact the fraction of steam when firing its mixtures with methane in a gas-turbine plant can be increased up to the weight ratio 4: 1. In this case, the concentrations of NO x and CO in emissions can be reduced to ultra-low values (less than 3 ppm).

Effects of Gravity on Supercritical Water Oxidation (SCWO) Processes

NASA Technical Reports Server (NTRS)

Hegde, Uday; Hicks, Michael

2013-01-01

The effects of gravity on the fluid mechanics of supercritical water jets are being studied at NASA to develop a better understanding of flow behaviors for purposes of advancing supercritical water oxidation (SCWO) technologies for applications in reduced gravity environments. These studies provide guidance for the development of future SCWO experiments in new experimental platforms that will extend the current operational range of the DECLIC (Device for the Study of Critical Liquids and Crystallization) Facility on board the International Space Station (ISS). The hydrodynamics of supercritical fluid jets is one of the basic unit processes of a SCWO reactor. These hydrodynamics are often complicated by significant changes in the thermo-physical properties that govern flow behavior (e.g., viscosity, thermal conductivity, specific heat, compressibility, etc), particularly when fluids transition from sub-critical to supercritical conditions. Experiments were conducted in a 150 ml reactor cell under constant pressure with water injections at various flow rates. Flow configurations included supercritical jets injected into either sub-critical or supercritical water. Profound gravitational influences were observed, particularly in the transition to turbulence, for the flow conditions under study. These results will be presented and the parameters of the flow that control jet behavior will be examined and discussed.

Supercritical carbon dioxide for textile applications and recent developments

NASA Astrophysics Data System (ADS)

Eren, H. A.; Avinc, O.; Eren, S.

2017-10-01

In textile industry, supercritical carbon dioxide (scCO2), possessing liquid-like densities, mostly find an application on textile dyeing processes such as providing hydrophobic dyes an advantage on dissolving. Their gas-like low viscosities and diffusion properties can result in shorter dyeing periods in comparison with the conventional water dyeing process. Supercritical carbon dioxide dyeing is an anhydrous dyeing and this process comprises the usage of less energy and chemicals when compared to conventional water dyeing processes leading to a potential of up to 50% lower operation costs. The advantages of supercritical carbon dioxide dyeing method especially on synthetic fiber fabrics hearten leading textile companies to alter their dyeing method to this privileged waterless dyeing technology. Supercritical carbon dioxide (scCO2) waterless dyeing is widely known and applied green method for sustainable and eco-friendly textile industry. However, not only the dyeing but also scouring, desizing and different finishing applications take the advantage of supercritical carbon dioxide (scCO2). In this review, not only the principle, advantages and disadvantages of dyeing in supercritical carbon dioxide but also recent developments of scCO2 usage in different textile processing steps such as scouring, desizing and finishing are explained and commercial developments are stated and summed up.

Chemical Reactions in Supercritical Carbon Dioxide

NASA Astrophysics Data System (ADS)

Wai, Chien M.; Hunt, Fred; Ji, Min; Chen, Xiaoyuan

1998-12-01

Utilizing supercritical fluids as environmentally benign solvents for chemical synthesis is one of the new approaches in the "greening" of chemistry. Carbon dioxide is the most widely used gas for supercritical fluid studies because of its moderate critical constants, nontoxic nature, and availability in pure form. One unique property of supercritical carbon dioxide (sc-CO2) is its high solubility for fluorinated compounds. Thus sc-CO2 can be used to replace Freons that are conventionally used as solvents for synthesis of perfluoro-polymers. Another property of sc-CO2 is its miscibility with gases such as H2. Heterogeneous reactions involving these gases may become homogeneous reactions in sc-CO2. Reactions in sc-CO2 may offer several advantages including controlling phase behavior and products, increasing speed of reactions, and obtaining specific reaction channels. This paper describes the following nine types of chemical reactions reported in the literature utilizing sc-CO2 as a solvent to illustrate the unique properties of the supercritical fluid reaction systems: (i) hydrogenation and hydroformylation, (ii) synthesis of organometallic compounds, (iii) metal chelation and extraction, (iv) preparation of inorganic nanoparticles, (v) stereo-selectivity of lipase-catalyzed reactions, (vi) asymmetric catalytic hydrogenation, (vii) polymerization, (viii) Diels-Alder reaction, and (ix) free radical reactions.

Field-portable supercritical CO{sub 2} extractor

DOEpatents

Wright, B.W.; Zemanian, T.S.; Robins, W.H.; Woodcock, L.J.

1997-06-10

The present invention is an apparatus for extracting organic compounds from solid materials. A generator vessel has a removable closure for receiving a solid or liquid solvent which is heated with a resistive heating element to a gaseous or supercritical phase. The removable closure is unencumbered because the side wall is penetrated with an outlet for the gaseous or supercritical solvent. The generator vessel further has a pressure transducer that provides an electronic signal related to pressure of the gaseous or supercritical solvent. The apparatus of the present invention further includes at least one extraction cell having a top and a bottom and a wall extending there between, wherein the bottom is sealably penetrated by an inlet for gaseous or supercritical solvent received through a manifold connected to the outlet, the top having an easy-open removable closure cap, and the wall having an outlet port. Finally, a permeable sample cartridge is included for holding the solid materials and to provide radial-flow of the extraction fluid, which is placed within the extraction cell. 10 figs.

Field-portable supercritical CO.sub.2 extractor

DOEpatents

Wright, Bob W.; Zemanian, Thomas S.; Robins, William H.; Woodcock, Leslie J.

1997-01-01

The present invention is an apparatus for extracting organic compounds from solid materials. A generator vessel has a removable closure for receiving a solid or liquid solvent which is heated with a resistive heating element to a gaseous or supercritical phase. The removable closure is unencumbered because the side wall is penetrated with an outlet for the gaseous or supercritical solvent. The generator vessel further has a pressure transducer that provides an electronic signal related to pressure of the gaseous or supercritical solvent. The apparatus of the present invention further includes at least one extraction cell having a top and a bottom and a wall extending therebetween, wherein the bottom is sealably penetrated by an inlet for gaseous or supercritical solvent received through a manifold connected to the outlet, the top having an easy-open removable closure cap, and the wall having an outlet port. Finally, a permeable sample cartridge is included for holding the solid materials and to provide radial-flow of the extraction fluid, which is placed within the extraction cell.

Hydrothermal Synthesis of Metal Oxide Nanoparticles in Supercritical Water

PubMed Central

Hayashi, Hiromichi; Hakuta, Yukiya

2010-01-01

This paper summarizes specific features of supercritical hydrothermal synthesis of metal oxide particles. Supercritical water allows control of the crystal phase, morphology, and particle size since the solvent's properties, such as density of water, can be varied with temperature and pressure, both of which can affect the supersaturation and nucleation. In this review, we describe the advantages of fine particle formation using supercritical water and describe which future tasks need to be solved. PMID:28883312

Steam trap monitor

DOEpatents

Ryan, Michael J.

1988-01-01

A steam trap monitor positioned downstream of a steam trap in a closed steam system includes a first sensor (the combination of a hot finger and thermocouple well) for measuring the energy of condensate and a second sensor (a cold finger) for measuring the total energy of condensate and steam in the line. The hot finger includes one or more thermocouples for detecting condensate level and energy, while the cold finger contains a liquid with a lower boiling temperature than that of water. Vapor pressure from the liquid is used to do work such as displacing a piston or bellows in providing an indication of total energy (steam+condensate) of the system. Processing means coupled to and responsive to outputs from the thermocouple well hot and cold fingers subtracts the condensate energy as measured by the hot finger and thermocouple well from the total energy as measured by the cold finger to provide an indication of the presence of steam downstream from the trap indicating that the steam trap is malfunctioning.

14. STEAM CABINETS & SITZ BATH IN STEAM ROOM. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. STEAM CABINETS & SITZ BATH IN STEAM ROOM. - Hot Springs National Park, Bathhouse Row, Fordyce Bathhouse: Mechanical & Piping Systems, State Highway 7, 1 mile north of U.S. Highway 70, Hot Springs, Garland County, AR

Supercritical Fluid Processing of Propellant Polymers

DTIC Science & Technology

1991-01-01

coffee decaffeination , spice extraction, and lipids purification. The processing principles have also long been well known and practiced in the...rn PL-TR-91 -3003 AD: AD-A234 285 Final Report Supercritical Fluid Processing for the period of Propellant Polymers September 1989 to September 1990...PROJECT TASK I’Ac K UNIT ELEMENT NO. NO. P:~53Co O 62302F 5730 0055 3𔃻U-- 11. TITLE (Include Security Classification) Supercritical Fluid Processing

Structural behavior of supercritical fluids under confinement

NASA Astrophysics Data System (ADS)

Ghosh, Kanka; Krishnamurthy, C. V.

2018-01-01

The existence of the Frenkel line in the supercritical regime of a Lennard-Jones (LJ) fluid shown through molecular dynamics (MD) simulations initially and later corroborated by experiments on argon opens up possibilities of understanding the structure and dynamics of supercritical fluids in general and of the Frenkel line in particular. The location of the Frenkel line, which demarcates two distinct physical states, liquidlike and gaslike within the supercritical regime, has been established through MD simulations of the velocity autocorrelation (VACF) and radial distribution function (RDF). We, in this article, explore the changes in the structural features of supercritical LJ fluid under partial confinement using atomistic walls. The study is carried out across the Frenkel line through a series of MD simulations considering a set of thermodynamics states in the supercritical regime (P =5000 bar, 240 K ≤T ≤1500 K ) of argon well above the critical point. Confinement is partial, with atomistic walls located normal to z and extending to "infinity" along the x and y directions. In the "liquidlike" regime of the supercritical phase, particles are found to be distributed in distinct layers along the z axis with layer spacing less than one atomic diameter and the lateral RDF showing amorphous-like structure for specific spacings (packing frustration) and non-amorphous-like structure for other spacings. Increasing the rigidity of the atomistic walls is found to lead to stronger layering and increased structural order. For confinement with reflective walls, layers are found to form with one atomic diameter spacing and the lateral RDF showing close-packed structure for the smaller confinements. Translational order parameter and excess entropy assessment confirms the ordering taking place for atomistic wall and reflective wall confinements. In the "gaslike" regime of the supercritical phase, particle distribution along the spacing and the lateral RDF exhibit features

Structural behavior of supercritical fluids under confinement.

PubMed

Ghosh, Kanka; Krishnamurthy, C V

2018-01-01

The existence of the Frenkel line in the supercritical regime of a Lennard-Jones (LJ) fluid shown through molecular dynamics (MD) simulations initially and later corroborated by experiments on argon opens up possibilities of understanding the structure and dynamics of supercritical fluids in general and of the Frenkel line in particular. The location of the Frenkel line, which demarcates two distinct physical states, liquidlike and gaslike within the supercritical regime, has been established through MD simulations of the velocity autocorrelation (VACF) and radial distribution function (RDF). We, in this article, explore the changes in the structural features of supercritical LJ fluid under partial confinement using atomistic walls. The study is carried out across the Frenkel line through a series of MD simulations considering a set of thermodynamics states in the supercritical regime (P=5000 bar, 240K≤T≤1500K) of argon well above the critical point. Confinement is partial, with atomistic walls located normal to z and extending to "infinity" along the x and y directions. In the "liquidlike" regime of the supercritical phase, particles are found to be distributed in distinct layers along the z axis with layer spacing less than one atomic diameter and the lateral RDF showing amorphous-like structure for specific spacings (packing frustration) and non-amorphous-like structure for other spacings. Increasing the rigidity of the atomistic walls is found to lead to stronger layering and increased structural order. For confinement with reflective walls, layers are found to form with one atomic diameter spacing and the lateral RDF showing close-packed structure for the smaller confinements. Translational order parameter and excess entropy assessment confirms the ordering taking place for atomistic wall and reflective wall confinements. In the "gaslike" regime of the supercritical phase, particle distribution along the spacing and the lateral RDF exhibit features not

Supercritical Fluid Infusion of Iron Additives in Polymeric Matrices

NASA Technical Reports Server (NTRS)

Nazem, Negin; Taylor, Larry T.

1999-01-01

The objective of this project was the experimentation to measure preparation of iron nanophases within polymeric matrices via supercritical fluid infusion of iron precursors followed by thermal reduction. Another objective was to determine if supercritical CO2 could infuse into the polymer. The experiment is described along with the materials, and the supercritical fluid infusion and cure procedures. X-ray photoelectron spectra and transmission electron micrographs were obtained. The results are summarized in charts, and tables.

Supercritical and Transcritical Real-Fluid Mixing in Diesel Engine Applications

DTIC Science & Technology

2015-09-01

ARL-RP-0551 ● SEP 2015 US Army Research Laboratory Supercritical and Transcritical Real-Fluid Mixing in Diesel Engine...ARL-RP-0551 ● SEP 2015 US Army Research Laboratory Supercritical and Transcritical Real-Fluid Mixing in Diesel Engine Applications by...COVERED (From - To) 1 January 2014–30 September 2014 4. TITLE AND SUBTITLE Supercritical and Transcritical Real-Fluid Mixing in Diesel Engine

Widom Lines in Binary Mixtures of Supercritical Fluids.

PubMed

Raju, Muralikrishna; Banuti, Daniel T; Ma, Peter C; Ihme, Matthias

2017-06-08

Recent experiments on pure fluids have identified distinct liquid-like and gas-like regimes even under supercritical conditions. The supercritical liquid-gas transition is marked by maxima in response functions that define a line emanating from the critical point, referred to as Widom line. However, the structure of analogous state transitions in mixtures of supercritical fluids has not been determined, and it is not clear whether a Widom line can be identified for binary mixtures. Here, we present first evidence for the existence of multiple Widom lines in binary mixtures from molecular dynamics simulations. By considering mixtures of noble gases, we show that, depending on the phase behavior, mixtures transition from a liquid-like to a gas-like regime via distinctly different pathways, leading to phase relationships of surprising complexity and variety. Specifically, we show that miscible binary mixtures have behavior analogous to a pure fluid and the supercritical state space is characterized by a single liquid-gas transition. In contrast, immiscible binary mixture undergo a phase separation in which the clusters transition separately at different temperatures, resulting in multiple distinct Widom lines. The presence of this unique transition behavior emphasizes the complexity of the supercritical state to be expected in high-order mixtures of practical relevance.

Determination of major aromatic constituents in vanilla using an on-line supercritical fluid extraction coupled with supercritical fluid chromatography.

PubMed

Liang, Yanshan; Liu, Jiaqi; Zhong, Qisheng; Shen, Lingling; Yao, Jinting; Huang, Taohong; Zhou, Ting

2018-04-01

An on-line supercritical fluid extraction coupled with supercritical fluid chromatography method was developed for the determination of four major aromatic constituents in vanilla. The parameters of supercritical fluid extraction were systematically investigated using single factor optimization experiments and response surface methodology by a Box-Behnken design. The modifier ratio, split ratio, and the extraction temperature and pressure were the major parameters which have significant effects on the extraction. While the static extraction time, dynamic extraction time, and recycle time had little influence on the compounds with low polarity. Under the optimized conditions, the relative extraction efficiencies of all the constituents reached 89.0-95.1%. The limits of quantification were in the range of 1.123-4.747 μg. The limits of detection were in the range of 0.3368-1.424 μg. The recoveries of the four analytes were in the range of 76.1-88.9%. The relative standard deviations of intra- and interday precision ranged from 4.2 to 7.6%. Compared with other off-line methods, the present method obtained higher extraction yields for all four aromatic constituents. Finally, this method has been applied to the analysis of vanilla from different sources. On the basis of the results, the on-line supercritical fluid extraction-supercritical fluid chromatography method shows great promise in the analysis of aromatic constituents in natural products. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transport relaxation processes in supercritical fluids

NASA Astrophysics Data System (ADS)

Jonas, J.

The technique for solubility measurements of solids in compressed supercritical fluids using NMR and theoretical analysis of experimental data on collision induced scattering were examined. Initial tests for a determination of solid solubilities in supercritical fluids without mixing were previously described and these preparations have continued. Super critical carbon dioxide dissolving naphthalene, for which solubility data is already available (M. McHugh, M.E. Paulaitis, J. Chem. Eng. Data, Vol. 25 (4), 1980) is being studied. This initial testing of the NMR technique for measuring solubilities in a well characterized system should prove very valuable for our later determinations with the proposed mixing probe. Systematic experimental studies of collision induced spectra in several supercritical fluids using both Raman and Rayleigh scattering are continued. The experimental work on SF6 and CH4 was finished and the experimental data testing of the various theoretical models for collision induced scattering is being analyzed.

Rapid method for quantification of seven synthetic pigments in colored Chinese steamed buns using UFLC-MS/MS without SPE.

PubMed

Gao, He-Gang; Gong, Wen-Jie; Zhao, Yong-Gang

2015-01-01

Synthetic pigments are still used instead of natural pigments in many foods and their residues in food could be an important risk to human health. A simple and rapid analytical method combining the low-cost extraction protocol with ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC-MS/MS) was developed for the simultaneous determination of seven synthetic pigments used in colored Chinese steamed buns. For the first time, ethanol/ammonia solution/water (7:2:1, v/v/v) was used as extraction solution for the synthetic pigments in colored Chinese steamed buns. The results showed that the property of the extraction solution used in this method was more effective than critic acid solution, which is used in the polyamide adsorption method. The limits of quantification for the seven synthetic pigments ranged from 0.15 to 0.50 μg/kg. The present method was successfully applied to samples of colored Chinese steamed buns for food-safety risk monitoring in Zhejiang Province, China. The results found sunset yellow pigment in six out of 300 colored Chinese steamed buns (from 0.50 to 32.6 μg/kg).

The NASA supercritical-wing technology

NASA Technical Reports Server (NTRS)

Bartlett, D. W.; Patterson, J. C., Jr.

1978-01-01

A number of high aspect ratio supercritical wings in combination with a representative wide body type fuselage were tested in the Langley 8 foot transonic pressure tunnel. The wing parameters investigated include aspect ratio, sweep, thickness to chord ratio, and camber. Subsequent to these initial series of tests, a particular wing configuration was selected for further study and development. Tests on the selected wing involved the incorporation of a larger inboard trailing edge extension, an inboard leading edge extension, and flow through nacelles. Range factors for the various supercritical wing configurations are compared with those for a reference wide body transport configuration.

Supercritical carbon dioxide-based sterilization of decellularized heart valves

PubMed Central

Hennessy, Ryan S.; Jana, Soumen; Tefft, Brandon J.; Helder, Meghana R.; Young, Melissa D.; Hennessy, Rebecca R.; Stoyles, Nicholas J.; Lerman, Amir

2017-01-01

Objective The goal of this research project encompasses finding the most efficient and effective method of decellularized tissue sterilization. Background Aortic tissue grafts have been utilized to repair damaged or diseased valves. Although, the tissues for grafting are collected aseptically, it does not eradicate the risk of contamination nor disease transfer. Thus, sterilization of grafts is mandatory. Several techniques have been applied to sterilize grafts; however, each technique shows drawbacks. In this study, we compared several sterilization techniques: supercritical carbon dioxide, electrolyzed water, gamma radiation, ethanol-peracetic acid, and hydrogen peroxide for impact on the sterility and mechanical integrity of porcine decellularized aortic valves. Methods Valve sterility was characterized by histology, microbe culture, and electron microscopy. Uniaxial tensile testing was conducted on the valve cusps along their circumferential orientation to study these sterilization techniques on their integrity. Results Ethanol-peracetic acid and supercritical carbon dioxide treated valves were found to be sterile. The tensile strength of supercritical carbon dioxide treated valves (4.28 ± 0.22 MPa) was higher to those valves treated with electrolyzed water, gamma radiation, ethanol-peracetic acid and hydrogen peroxide (1.02 ± 0.15, 1.25 ± 0.25, 3.53 ± 0.41 and 0.37 ± 0.04 MPa, respectively). Conclusions Superior sterility and integrity were found in the decellularized porcine aortic valves with supercritical carbon dioxide sterilization. This sterilization technique may hold promise for other decellularized soft tissues. Summary Sterilization of grafts is essential. Supercritical carbon dioxide, electrolyzed water, gamma radiation, ethanol-peracetic acid, and hydrogen peroxide techniques were compared for impact on sterility and mechanical integrity of porcine decellularized aortic valves. Ethanol-peracetic acid and supercritical carbon dioxide treated

Supercritical carbon dioxide-based sterilization of decellularized heart valves.

PubMed

Hennessy, Ryan S; Jana, Soumen; Tefft, Brandon J; Helder, Meghana R; Young, Melissa D; Hennessy, Rebecca R; Stoyles, Nicholas J; Lerman, Amir

2017-02-01

The goal of this research project encompasses finding the most efficient and effective method of decellularized tissue sterilization. Aortic tissue grafts have been utilized to repair damaged or diseased valves. Although, the tissues for grafting are collected aseptically, it does not eradicate the risk of contamination nor disease transfer. Thus, sterilization of grafts is mandatory. Several techniques have been applied to sterilize grafts; however, each technique shows drawbacks. In this study, we compared several sterilization techniques: supercritical carbon dioxide, electrolyzed water, gamma radiation, ethanol-peracetic acid, and hydrogen peroxide for impact on the sterility and mechanical integrity of porcine decellularized aortic valves. Valve sterility was characterized by histology, microbe culture, and electron microscopy. Uniaxial tensile testing was conducted on the valve cusps along their circumferential orientation to study these sterilization techniques on their integrity. Ethanol-peracetic acid and supercritical carbon dioxide treated valves were found to be sterile. The tensile strength of supercritical carbon dioxide treated valves (4.28 ± 0.22 MPa) was higher to those valves treated with electrolyzed water, gamma radiation, ethanol-peracetic acid and hydrogen peroxide (1.02 ± 0.15, 1.25 ± 0.25, 3.53 ± 0.41 and 0.37 ± 0.04 MPa, respectively). Superior sterility and integrity were found in the decellularized porcine aortic valves with supercritical carbon dioxide sterilization. This sterilization technique may hold promise for other decellularized soft tissues. Sterilization of grafts is essential. Supercritical carbon dioxide, electrolyzed water, gamma radiation, ethanol-peracetic acid, and hydrogen peroxide techniques were compared for impact on sterility and mechanical integrity of porcine decellularized aortic valves. Ethanol-peracetic acid and supercritical carbon dioxide treated valves were found to be sterile using histology, microbe

Supercritical Water Process for the Chemical Recycling of Waste Plastics

NASA Astrophysics Data System (ADS)

Goto, Motonobu

2010-11-01

The development of chemical recycling of waste plastics by decomposition reactions in sub- and supercritical water is reviewed. Decomposition reactions proceed rapidly and selectively using supercritical fluids compared to conventional processes. Condensation polymerization plastics such as PET, nylon, and polyurethane, are relatively easily depolymerized to their monomers in supercritical water. The monomer components are recovered in high yield. Addition polymerization plastics such as phenol resin, epoxy resin, and polyethylene, are also decomposed to monomer components with or without catalysts. Recycling process of fiber reinforced plastics has been studied. Pilot scale or commercial scale plants have been developed and are operating with sub- and supercritical fluids.

Supercritical convection, critical heat flux, and coking characteristics of propane

NASA Technical Reports Server (NTRS)

Rousar, D. C.; Gross, R. S.; Boyd, W. C.

1984-01-01

The heat transfer characteristics of propane at subcritical and supercritical pressure were experimentally evaluated using electrically heated Monel K-500 tubes. A design correlation for supercritical heat transfer coefficient was established using the approach previously applied to supercritical oxygen. Flow oscillations were observed and the onset of these oscillations at supercritical pressures was correlated with wall-to-bulk temperature ratio and velocity. The critical heat flux measured at subcritical pressure was correlated with the product of velocity and subcooling. Long duration tests at fixed heat flux conditions were conducted to evaluate coking on the coolant side tube wall and coking rates comparable to RP-1 were observed.

LOX droplet vaporization in a supercritical forced convective environment

NASA Technical Reports Server (NTRS)

Hsiao, Chia-Chun; Yang, Vigor

1993-01-01

Modern liquid rocket engines often use liquid oxygen (LOX) and liquid hydrogen (LH2) as propellants to achieve high performance, with the engine operational conditions in the supercritical regimes of the propellants. Once the propellant exceeds its critical state, it essentially becomes a puff of dense fluid. The entire field becomes a continuous medium, and no distinct interfacial boundary between the liquid and gas exists. Although several studies have been undertaken to investigate the supercritical droplet behavior at quiescent conditions, very little effort has been made to address the fundamental mechanisms associated with LOX droplet vaporization in a supercritical, forced convective environment. The purpose is to establish a theoretical framework within which supercritical droplet dynamics and vaporization can be studied systematically by means of an efficient and robust numerical algorithm.

Downhole steam injector

DOEpatents

Donaldson, A. Burl; Hoke, Donald E.

1983-01-01

An improved downhole steam injector has an angled water orifice to swirl the water through the device for improved heat transfer before it is converted to steam. The injector also has a sloped diameter reduction in the steam chamber to throw water that collects along the side of the chamber during slant drilling into the flame for conversion to steam. In addition, the output of the flame chamber is beveled to reduce hot spots and increase efficiency, and the fuel-oxidant inputs are arranged to minimize coking.

Electrodeposition of germanium from supercritical fluids.

PubMed

Ke, Jie; Bartlett, Philip N; Cook, David; Easun, Timothy L; George, Michael W; Levason, William; Reid, Gillian; Smith, David; Su, Wenta; Zhang, Wenjian

2012-01-28

Several Ge(II) and Ge(IV) compounds were investigated as possible reagents for the electrodeposition of Ge from liquid CH(3)CN and CH(2)F(2) and supercritical CO(2) containing as a co-solvent CH(3)CN (scCO(2)) and supercritical CH(2)F(2) (scCH(2)F(2)). For Ge(II) reagents the most promising results were obtained using [NBu(n)(4)][GeCl(3)]. However the reproducibility was poor and the reduction currents were significantly less than the estimated mass transport limited values. Deposition of Ge containing films was possible at high cathodic potential from [NBu(n)(4)][GeCl(3)] in liquid CH(3)CN and supercritical CO(2) containing CH(3)CN but in all cases they were heavily contaminated by C, O, F and Cl. Much more promising results were obtained using GeCl(4) in liquid CH(2)F(2) and supercritical CH(2)F(2). In this case the reduction currents were consistent with mass transport limited reduction and bulk electrodeposition produced amorphous films of Ge. Characterisation by XPS showed the presence of low levels of O, F and C, XPS confirmed the presence of Ge together with germanium oxides, and Raman spectroscopy showed that the as deposited amorphous Ge could be crystallised by the laser used in obtaining the Raman measurements.

Chemical deposition methods using supercritical fluid solutions

DOEpatents

Sievers, Robert E.; Hansen, Brian N.

1990-01-01

A method for depositing a film of a desired material on a substrate comprises dissolving at least one reagent in a supercritical fluid comprising at least one solvent. Either the reagent is capable of reacting with or is a precursor of a compound capable of reacting with the solvent to form the desired product, or at least one additional reagent is included in the supercritical solution and is capable of reacting with or is a precursor of a compound capable of reacting with the first reagent or with a compound derived from the first reagent to form the desired material. The supercritical solution is expanded to produce a vapor or aerosol and a chemical reaction is induced in the vapor or aerosol so that a film of the desired material resulting from the chemical reaction is deposited on the substrate surface. In an alternate embodiment, the supercritical solution containing at least one reagent is expanded to produce a vapor or aerosol which is then mixed with a gas containing at least one additional reagent. A chemical reaction is induced in the resulting mixture so that a film of the desired material is deposited.

Improved Sterilization of Sensitive Biomaterials with Supercritical Carbon Dioxide at Low Temperature

PubMed Central

Bernhardt, Anne; Wehrl, Markus; Paul, Birgit; Hochmuth, Thomas; Schumacher, Matthias; Schütz, Kathleen; Gelinsky, Michael

2015-01-01

The development of bio-resorbable implant materials is rapidly going on. Sterilization of those materials is inevitable to assure the hygienic requirements for critical medical devices according to the medical device directive (MDD, 93/42/EG). Biopolymer-containing biomaterials are often highly sensitive towards classical sterilization procedures like steam, ethylene oxide treatment or gamma irradiation. Supercritical CO2 (scCO2) treatment is a promising strategy for the terminal sterilization of sensitive biomaterials at low temperature. In combination with low amounts of additives scCO2 treatment effectively inactivates microorganisms including bacterial spores. We established a scCO2 sterilization procedure under addition of 0.25% water, 0.15% hydrogen peroxide and 0.5% acetic anhydride. The procedure was successfully tested for the inactivation of a wide panel of microorganisms including endospores of different bacterial species, vegetative cells of gram positive and negative bacteria including mycobacteria, fungi including yeast, and bacteriophages. For robust testing of the sterilization effect with regard to later application of implant materials sterilization all microorganisms were embedded in alginate/agarose cylinders that were used as Process Challenge Devices (PCD). These PCD served as surrogate models for bioresorbable 3D scaffolds. Furthermore, the impact of scCO2 sterilization on mechanical properties of polysaccharide-based hydrogels and collagen-based scaffolds was analyzed. The procedure was shown to be less compromising on mechanical and rheological properties compared to established low-temperature sterilization methods like gamma irradiation and ethylene oxide exposure as well as conventional steam sterilization. Cytocompatibility of alginate gels and scaffolds from mineralized collagen was compared after sterilization with ethylene oxide, gamma irradiation, steam sterilization and scCO2 treatment. Human mesenchymal stem cell viability and

Contents Changes of Triterpenic Acids, Nucleosides, Nucleobases, and Saccharides in Jujube (Ziziphus jujuba) Fruit During the Drying and Steaming Process.

PubMed

Guo, Sheng; Duan, Jin-Ao; Zhang, Ying; Qian, Dawei; Tang, Yuping; Zhu, Zhenhua; Wang, Hanqing

2015-12-12

Chinese jujube (Ziziphus jujuba), a medicinal and edible plant, is widely consumed in Asian countries owing to the remarkable health activities of its fruits. To facilitate selection of the suitable processing method for jujube fruits, in this study their contents of triterpenic acids, nucleosides, nucleobases and saccharides after drying and steaming treatment were determined using ultra-high performance liquid chromatography and high performance liquid chromatography coupled with evaporative light scattering detector methods. The results showed that except for sucrose, the content levels of most analytes were increasing in the jujube fruits during drying treatment at 45 °C. The levels of cyclic nucleotides such as adenosine 3',5'-cyclic monophosphate and guanosine 3',5'-cyclic monophosphate, were significantly decreased after the fruits were steamed. Therefore, owing to the bioactivities of these components for human health, the dried fruits would be the better choice as medicinal material or functional food, and dried jujube fruit should not be further steamed.

High Density Thermal Energy Storage with Supercritical Fluids

NASA Technical Reports Server (NTRS)

Ganapathi, Gani B.; Wirz, Richard

2012-01-01

A novel approach to storing thermal energy with supercritical fluids is being investigated, which if successful, promises to transform the way thermal energy is captured and utilized. The use of supercritical fluids allows cost-affordable high-density storage with a combination of latent heat and sensible heat in the two-phase as well as the supercritical state. This technology will enhance penetration of several thermal power generation applications and high temperature water for commercial use if the overall cost of the technology can be demonstrated to be lower than the current state-of-the-art molten salt using sodium nitrate and potassium nitrate eutectic mixtures.

Selective free radical reactions using supercritical carbon dioxide.

PubMed

Cormier, Philip J; Clarke, Ryan M; McFadden, Ryan M L; Ghandi, Khashayar

2014-02-12

We report herein a means to modify the reactivity of alkenes, and particularly to modify their selectivity toward reactions with nonpolar reactants (e.g., nonpolar free radicals) in supercritical carbon dioxide near the critical point. Rate constants for free radical addition of the light hydrogen isotope muonium to ethylene, vinylidene fluoride, and vinylidene chloride in supercritical carbon dioxide are compared over a range of pressures and temperatures. Near carbon dioxide's critical point, the addition to ethylene exhibits critical speeding up, while the halogenated analogues display critical slowing. This suggests that supercritical carbon dioxide as a solvent may be used to tune alkene chemistry in near-critical conditions.

Prospects of Supercritical Fluids in Realizing Graphene-Based Functional Materials.

PubMed

Padmajan Sasikala, Suchithra; Poulin, Philippe; Aymonier, Cyril

2016-04-13

Supercritical-fluids science and technology predate all the approaches that are currently established for graphene production by several decades in advanced materials design. However, it has only recently been proposed as a plausible approach for graphene processing. Since then, supercritical fluids have emerged into contention as an alternative to existing technologies because of their scalability and versatility in processing graphene materials, which include composites, aerogels, and foams. Here, an overview is presented of such materials prepared through supercritical fluids from an advanced materials science standpoint, with a discussion on their fundamental properties and technological applications. The benefits of supercritical-fluid processing over conventional liquid-phase processing are presented. The benefits include not only better performances for advanced applications but also environmental issues associated with the synthesis process. Nevertheless, the limitations of supercritical-fluid processing are also stressed, along with challenges that are still faced toward the achievement of the great expectations from graphene materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DNS of High Pressure Supercritical Combustion

NASA Astrophysics Data System (ADS)

Chong, Shao Teng; Raman, Venkatramanan

2016-11-01

Supercritical flows have always been important to rocket motors, and more recently to aircraft engines and stationary gas turbines. The purpose of the present study is to understand effects of differential diffusion on reacting scalars using supercritical isotropic turbulence. Focus is on fuel and oxidant reacting in the transcritical region where density, heat capacity and transport properties are highly sensitive to variations in temperature and pressure. Reynolds and Damkohler number vary as a result and although it is common to neglect differential diffusion effects if Re is sufficiently large, this large variation in temperature with heat release can accentuate molecular transport differences. Direct numerical simulations (DNS) for one step chemistry reaction between fuel and oxidizer are used to examine the differential diffusion effects. A key issue investigated in this paper is if the flamelet progress variable approach, where the Lewis number is usually assumed to be unity and constant for all species, can be accurately applied to simulate supercritical combustion.

Steam generator support system

DOEpatents

Moldenhauer, James E.

1987-01-01

A support system for connection to an outer surface of a J-shaped steam generator for use with a nuclear reactor or other liquid metal cooled power source. The J-shaped steam generator is mounted with the bent portion at the bottom. An arrangement of elongated rod members provides both horizontal and vertical support for the steam generator. The rod members are interconnected to the steam generator assembly and a support structure in a manner which provides for thermal distortion of the steam generator without the transfer of bending moments to the support structure and in a like manner substantially minimizes forces being transferred between the support structure and the steam generator as a result of seismic disturbances.

Supercritical Fluid Extraction of Bioactive Compounds from Plant Materials.

PubMed

Wrona, Olga; Rafińska, Katarzyna; Możeński, Cezary; Buszewski, Bogusław

2017-11-01

There has been growing interest in the application of supercritical solvents over the last several years, many of the applications industrial in nature. The purpose of plant material extraction is to obtain large amounts of extract rich in the desired active compounds in a time-sensitive and cost-effective manner. The productivity and profitability of a supercritical fluid extraction (SFE) process largely depends on the selection of process parameters, which are elaborated upon in this paper. Carbon dioxide (CO2) is the most desirable solvent for the supercritical extraction of natural products. Its near-ambient critical temperature makes it suitable for the extraction of thermolabile components without degradation. A new approach has been adopted for SFE in which the solubility of nonpolar supercritical CO2 can be enhanced by the addition of small amounts of cosolvent.

METHOD FOR THE SUPERCRITICAL FLUID EXTRACTION OF SOILS/SEDIMENTS

EPA Science Inventory

Supercritical fluid extraction has been publicized as an extraction method which has several advantages over conventional methods, and it is expected to result in substantial cost and labor savings. This study was designed to evaluate the feasibility of using supercritical fluid ...

Steam generator support system

DOEpatents

Moldenhauer, J.E.

1987-08-25

A support system for connection to an outer surface of a J-shaped steam generator for use with a nuclear reactor or other liquid metal cooled power source is disclosed. The J-shaped steam generator is mounted with the bent portion at the bottom. An arrangement of elongated rod members provides both horizontal and vertical support for the steam generator. The rod members are interconnected to the steam generator assembly and a support structure in a manner which provides for thermal distortion of the steam generator without the transfer of bending moments to the support structure and in a like manner substantially minimizes forces being transferred between the support structure and the steam generator as a result of seismic disturbances. 4 figs.

Supercritical-Fluid Extraction of Oil From Tar Sands

NASA Technical Reports Server (NTRS)

Compton, L. E.

1982-01-01

New supercritical solvent mixtures have been laboratory-tested for extraction of oil from tar sands. Mixture is circulated through sand at high pressure and at a temperature above critical point, dissolving organic matter into the compressed gas. Extract is recovered from sand residues. Low-temperature super-critical solvents reduce energy consumption and waste-disposal problems.

Functioning efficiency of intermediate coolers of multistage steam-jet ejectors of steam turbines

NASA Astrophysics Data System (ADS)

Aronson, K. E.; Ryabchikov, A. Yu.; Brodov, Yu. M.; Zhelonkin, N. V.; Murmanskii, I. B.

2017-03-01

Designs of various types of intermediate coolers of multistage ejectors are analyzed and thermal effectiveness and gas-dynamic resistance of coolers are estimated. Data on quantity of steam condensed from steam-air mixture in stage I of an ejector cooler was obtained on the basis of experimental results. It is established that the amount of steam condensed in the cooler constitutes 0.6-0.7 and is almost independent of operating steam pressure (and, consequently, of steam flow) and air amount in steam-air mixture. It is suggested to estimate the amount of condensed steam in a cooler of stage I based on comparison of computed and experimental characteristics of stage II. Computation taking this hypothesis for main types of mass produced multistage ejectors into account shows that 0.60-0.85 of steam amount should be condensed in stage I of the cooler. For ejectors with "pipe-in-pipe" type coolers (EPO-3-200) and helical coolers (EO-30), amount of condensed steam may reach 0.93-0.98. Estimation of gas-dynamic resistance of coolers shows that resistance from steam side in coolers with built-in and remote pipe bundle constitutes 100-300 Pa. Gas-dynamic resistance of "pipein- pipe" and helical type coolers is significantly higher (3-6 times) compared with pipe bundle. However, performance by "dry" (atmospheric) air is higher for ejectors with relatively high gas-dynamic resistance of coolers than those with low resistance at approximately equal operating flow values of ejectors.

Supercritical fluid chromatography for lipid analysis in foodstuffs.

PubMed

Donato, Paola; Inferrera, Veronica; Sciarrone, Danilo; Mondello, Luigi

2017-01-01

The task of lipid analysis has always challenged separation scientists, and new techniques in chromatography were often developed for the separation of lipids; however, no single technique or methodology is yet capable of affording a comprehensive screening of all lipid species and classes. This review acquaints the role of supercritical fluid chromatography within the field of lipid analysis, from the early developed capillary separations based on pure CO 2 , to the most recent techniques employing packed columns under subcritical conditions, including the niche multidimensional techniques using supercritical fluids in at least one of the separation dimensions. A short history of supercritical fluid chromatography will be introduced first, from its early popularity in the late 1980s, to the sudden fall and oblivion until the last decade, experiencing a regain of interest within the chromatographic community. Afterwards, the subject of lipid nomenclature and classification will be briefly dealt with, before discussing the main applications of supercritical fluid chromatography for food analysis, according to the specific class of lipids. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A universal salt model based on under-ground precipitation of solid salts due to supercritical water `out-salting'

NASA Astrophysics Data System (ADS)

Rueslåtten, H.; Hovland, M. T.

2010-12-01

One of the common characteristics of planets Earth and Mars is that both host water (H2O) and large accumulations of salt. Whereas Earth’s surface-environment can be regarded as ‘water-friendly’ and ‘salt hostile’, the reverse can be said for the surface of Mars. This is because liquid water is stable on Earth, and the atmosphere transports humidity around the globe, whereas on planet Mars, liquid water is unstable, rendering the atmosphere dry and, therefore, ‘salt-friendly’. The riddle as to how the salt accumulated in various locations on those two planets, is one of long-lasting and great debate. The salt accumulations on Earth are traditionally termed ‘evaporites’, meaning that they formed as a consequence of the evaporation of large masses of seawater. How the accumulations on Mars formed is much harder to explain, as an ocean only existed briefly. Although water molecules and OH-groups may exist in abundance in bound form (crystal water, adsorbed water, etc.), the only place where free water is expected to be stable on Mars is within underground faults, fractures, and crevices. Here it likely occurs as brine or in the form of ice. Based on these conditions, a key to understanding the accumulation of large deposits of salt on both planets is linked to how brines behave in the subsurface when pressurized and heated beyond their supercritical point. At depths greater than about 3 km (P>300 bars) water will no longer boil in a steam phase. Rather, it becomes supercritical and will attain the phase of supercritical water vapor (SCRIW) with a specific gravity of typically 0.3 g/cm3. An important characteristic of SCRIW is its inability to dissolve the common sea salts. The salt dissolved in the brines will therefore precipitate as solid particles when brines (seawater on the Earth) move into the supercritical P&T-domain (T>400°C, P>300 bars). Numerical modeling of a hydrothermal system in the Atlantis II Deep of the Red Sea indicates that a

Physical properties of the benchmark models program supercritical wing

NASA Technical Reports Server (NTRS)

Dansberry, Bryan E.; Durham, Michael H.; Bennett, Robert M.; Turnock, David L.; Silva, Walter A.; Rivera, Jose A., Jr.

1993-01-01

The goal of the Benchmark Models Program is to provide data useful in the development and evaluation of aeroelastic computational fluid dynamics (CFD) codes. To that end, a series of three similar wing models are being flutter tested in the Langley Transonic Dynamics Tunnel. These models are designed to simultaneously acquire model response data and unsteady surface pressure data during wing flutter conditions. The supercritical wing is the second model of this series. It is a rigid semispan model with a rectangular planform and a NASA SC(2)-0414 supercritical airfoil shape. The supercritical wing model was flutter tested on a flexible mount, called the Pitch and Plunge Apparatus, that provides a well-defined, two-degree-of-freedom dynamic system. The supercritical wing model and associated flutter test apparatus is described and experimentally determined wind-off structural dynamic characteristics of the combined rigid model and flexible mount system are included.

Synthesis and characterization of nanocrystalline mesoporous zirconia using supercritical drying.

PubMed

Tyagi, Beena; Sidhpuria, Kalpesh; Shaik, Basha; Jasra, Raksh Vir

2006-06-01

Synthesis of nano-crystalline zirconia aerogel was done by sol-gel technique and supercritical drying using n-propanol solvent at and above supercritical temperature (235-280 degrees C) and pressure (48-52 bar) of n-propanol. Zirconia xerogel samples have also been prepared by conventional thermal drying method to compare with the super critically dried samples. Crystalline phase, crystallite size, surface area, pore volume, and pore size distribution were determined for all the samples in detail to understand the effect of gel drying methods on these properties. Supercritical drying of zirconia gel was observed to give thermally stable, nano-crystalline, tetragonal zirconia aerogels having high specific surface area and porosity with narrow and uniform pore size distribution as compared to thermally dried zirconia. With supercritical drying, zirconia samples show the formation of only mesopores whereas in thermally dried samples, substantial amount of micropores are observed along with mesopores. The samples prepared using supercritical drying yield nano-crystalline zirconia with smaller crystallite size (4-6 nm) as compared to higher crystallite size (13-20 nm) observed with thermally dried zirconia.

Steamer of steam circulation system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onodera, M.

1986-09-23

A conveyor steamer is described which consists of: a room enclosed with heat-insulated walls, floor, and ceiling, the room having an entrance and an exit for goods to be steamed, a conveyor means for carrying the goods to be steamed, the conveyor means traversing into the entrance of the room, through the room, and out of the exit of the room; a source of heated primary steam; first pipe means, arranged beneath the conveyor means, for jetting the heated primary steam upwardly from across the floor of the room; second pipe means disposed across the entire ceiling of the roommore » arranged above the conveyor means, for scavenging spent steam from across the entire ceiling of the room; and an ejector-condenser means, interconnected between the first pipe means, the source of primary heated steam and the second pipe means, for mixing the spent steam from the second pipe means with the heated primary steam in the first pipe means; whereby the spent steam mixed with the heated primary steam is caused to recirculate in the first pipe means through the room, thus saving energy and consuming less heated primary steam so that cost reductions will result.« less

Supercritical solvent extraction of oil sand bitumen

NASA Astrophysics Data System (ADS)

Imanbayev, Ye. I.; Ongarbayev, Ye. K.; Tileuberdi, Ye.; Mansurov, Z. A.; Golovko, A. K.; Rudyk, S.

2017-08-01

The supercritical solvent extraction of bitumen from oil sand studied with organic solvents. The experiments were performed in autoclave reactor at temperature above 255 °C and pressure 29 atm with stirring for 6 h. The reaction resulted in the formation of coke products with mineral part of oil sands. The remaining products separated into SARA fractions. The properties of the obtained products were studied. The supercritical solvent extraction significantly upgraded extracted natural bitumen.

Advanced Stimulated Scattering Measurements in Supercritical Fluids

DTIC Science & Technology

2006-09-01

supercritical fluid measurement techniques. Ajay Agrawal, optical diagnostics. Mel Roquemore, turbine engines. Fred Schauer, pulse detonation propulsion...Lett. 87, 233902 (2001). 11. R. W. Gammon, H. L. Swinney, and H. Z. Cummins, "Brillouin scattering in carbon dioxide in the critical region," Phys. Rev...Stimulated Scattering Measurements in Supercritical F49620-03-C-0015 Fluids 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) 5d

Supercritical extraction of lycopene from tomato industrial wastes with ethane.

PubMed

Nobre, Beatriz P; Gouveia, Luisa; Matos, Patricia G S; Cristino, Ana F; Palavra, António F; Mendes, Rui L

2012-07-11

Supercritical fluid extraction of all-E-lycopene from tomato industrial wastes (mixture of skins and seeds) was carried out in a semi-continuous flow apparatus using ethane as supercritical solvent. The effect of pressure, temperature, feed particle size, solvent superficial velocity and matrix initial composition was evaluated. Moreover, the yield of the extraction was compared with that obtained with other supercritical solvents (supercritical CO₂ and a near critical mixture of ethane and propane). The recovery of all-E-lycopene increased with pressure, decreased with the increase of the particle size in the initial stages of the extraction and was not practically affected by the solvent superficial velocity. The effect of the temperature was more complex. When the temperature increased from 40 to 60 °C the recovery of all-E-lycopene increased from 80 to 90%. However, for a further increase to 80 °C, the recovery remained almost the same, indicating that some E-Z isomerization could have occurred, as well as some degradation of lycopene. The recovery of all-E-lycopene was almost the same for feed samples with different all-E-lycopene content. Furthermore, when a batch with a higher all-E-lycopene content was used, supercritical ethane and a near critical mixture of ethane and propane showed to be better solvents than supercritical CO₂ leading to a faster extraction with a higher recovery of the carotenoid.

Carotenoids microencapsulation by spray drying method and supercritical micronization.

PubMed

Janiszewska-Turak, Emilia

2017-09-01

Carotenoids are used as natural food colourants in the food industry. As unstable natural pigments they need protection. This protection can involve the microencapsulation process. There are numerous techniques that can be used for carotenoid protection, but two of them -spray drying and supercritical micronization - are currently the most commonly used. The objective of this paper is to describe these two techniques for carotenoid microencapsulation. In this review information from articles from the last five years was taken into consideration. Pigments described in the review are all carotenoids. Short summary of carotenoids sources was presented. For the spray drying technique, a review of carrier material and process conditions was made. Moreover, a short description of some of the most suitable processes involving supercritical fluids for carotenoids (astaxanthin, β-carotene, lutein and lycopene) encapsulation was given. These include the Supercritical Antisolvent process (SAS), Particles from Gas-Saturated Solutions (PGSS), Supercritical Fluid Extraction From an Emulsion (SFEE) and Solution Enhanced Dispersion by Supercritical fluids (SEDS). In most cases the studies, independently of the described method, were conducted on the laboratory scale. In some a scale-up was also tested. In the review a critical assessment of the used methods was made. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fundamental kinetics and mechanistic pathways for oxidation reactions in supercritical water

NASA Technical Reports Server (NTRS)

Webley, Paul A.; Tester, Jefferson W.

1988-01-01

Oxidation of the products of human metabolism in supercritical water has been shown to be an efficient way to accomplish the on-board water/waste recycling in future long-term space flights. Studies of the oxidation kinetics of methane to carbon dioxide in supercritical water are presented in this paper in order to enhance the fundamental understanding of the oxidation of human waste compounds in supercritical water. It is concluded that, although the elementary reaction models remain the best hope for simulating oxidation in supercritical water, several modifications to existing mechanisms need to be made to account for the role of water in the reaction mechanism.

System Modeling for Ammonia Synthesis Energy Recovery System

NASA Astrophysics Data System (ADS)

Bran Anleu, Gabriela; Kavehpour, Pirouz; Lavine, Adrienne; Ammonia thermochemical Energy Storage Team

2015-11-01

An ammonia thermochemical energy storage system is an alternative solution to the state-of-the-art molten salt TES system for concentrating solar power. Some of the advantages of this emerging technology include its high energy density, no heat losses during the storage duration, and the possibility of long storage periods. Solar energy powers an endothermic reaction to disassociate ammonia into hydrogen and nitrogen, which can be stored for future use. The reverse reaction is carried out in the energy recovery process; a hydrogen-nitrogen mixture flowing through a catalyst bed undergoes the exothermic ammonia synthesis reaction. The goal is to use the ammonia synthesis reaction to heat supercritical steam to temperatures on the order of 650°C as required for a supercritical steam Rankine cycle. The steam will flow through channels in a combined reactor-heat exchanger. A numerical model has been developed to determine the optimal design to heat supercritical steam while maintaining a stable exothermic reaction. The model consists of a transient one dimensional concentric tube counter-flow reactor-heat exchanger. The numerical model determines the inlet mixture conditions needed to achieve various steam outlet conditions.

Environmentally Friendly Replacement of Mature 200 MW Coal-Fired Power Blocks with 2 Boilers Working on One 500 MW Class Steam Turbine Generator (2on1 Unit Concept)

NASA Astrophysics Data System (ADS)

Grzeszczak, Jan; Grela, Łukasz; Achter, Thomas

2017-12-01

The paper covers problems of the owners of a fleet of long-operated conventional power plants that are going to be decommissioned soon in result of failing to achieve new admissible emissions levels or exceeding pressure elements design lifetime. Energoprojekt-Katowice SA, Siemens AG and Rafako SA presents their joint concept of the solution which is a 2on1 concept - replacing two unit by two ultra-supercritical boilers feeding one turbine. Polish market has been taken as an example.

Supercritical Fluid Facilitated Growth of Copper and Aluminum Oxide Nanoparticles

ERIC Educational Resources Information Center

Williams, Geoffrey L.; Vohs, Jason K.; Brege, Jonathan J.; Fahlman, Bradley D.

2005-01-01

Supercritical fluids (SCFs) possess properties that are intermediate between liquids and gases. The combination of supercritical fluid technology with advanced characterization techniques such as electron microscopy provided a practical and rewarding undergraduate laboratory experiment.

Geologic controls on supercritical geothermal resources above magmatic intrusions

PubMed Central

Scott, Samuel; Driesner, Thomas; Weis, Philipp

2015-01-01

A new and economically attractive type of geothermal resource was recently discovered in the Krafla volcanic system, Iceland, consisting of supercritical water at 450 °C immediately above a 2-km deep magma body. Although utilizing such supercritical resources could multiply power production from geothermal wells, the abundance, location and size of similar resources are undefined. Here we present the first numerical simulations of supercritical geothermal resource formation, showing that they are an integral part of magma-driven geothermal systems. Potentially exploitable resources form in rocks with a brittle–ductile transition temperature higher than 450 °C, such as basalt. Water temperatures and enthalpies can exceed 400 °C and 3 MJ kg−1, depending on host rock permeability. Conventional high-enthalpy resources result from mixing of ascending supercritical and cooler surrounding water. Our models reproduce the measured thermal conditions of the resource discovered at Krafla. Similar resources may be widespread below conventional high-enthalpy geothermal systems. PMID:26211617

Supercritical fluid technology: a promising approach in pharmaceutical research.

PubMed

Girotra, Priti; Singh, Shailendra Kumar; Nagpal, Kalpana

2013-02-01

Supercritical fluids possess the unique properties of behaving like liquids and gases, above their critical point. Supercritical fluid technology has recently emerged as a green and novel technique for various processes such as solubility enhancement of poorly soluble drugs, plasticization of polymers, surface modification, nanosizing and nanocrystal modification, and chromatographic extraction. Research interest in this area has been fuelled because of the numerous advantages that the technology offers over the conventional methods. This work aims to review the merits, demerits, and various processes such as rapid expansion of supercritical solutions (RESS), particles from gas saturated solutions (PGSS), gas antisolvent process (GAS), supercritical antisolvent process (SAS) and polymerization induced phase separation (PIPS), that have enabled this technology to considerably raise the interest of researchers over the past two decades. An insight has been given into the numerous applications of this technology in pharmaceutical industry and the future challenges which must be appropriately dealt with to make it effective on a commercial scale.

Simultaneous Graphite Exfoliation and N Doping in Supercritical Ammonia.

PubMed

Sasikala, Suchithra Padmajan; Huang, Kai; Giroire, Baptiste; Prabhakaran, Prem; Henry, Lucile; Penicaud, Alain; Poulin, Philippe; Aymonier, Cyril

2016-11-16

We report the exfoliation of graphite and simultaneous N doping of graphene by two methods: supercritical ammonia treatment and liquid-phase exfoliation with NH 4 OH. While the supercritical ammonia allowed N doping at a level of 6.4 atom % in 2 h, the liquid-phase exfoliation with NH 4 OH allowed N doping at a level of 2.7 atom % in 6 h. The N doped graphene obtained via the supercritical ammonia route had few layers (<5) and showed large lateral flake size (∼8 μm) and low defect density (I D /I G < 0.6) in spite of their high level of N doping. This work is the first demonstration of supercritical ammonia as an exfoliation agent and N doping precursor for graphene. Notably, the N doped graphene showed electrocatalytic activity toward oxygen reduction reaction with high durability and good methanol tolerance compared to those of commercial Pt/C catalyst.

Geologic controls on supercritical geothermal resources above magmatic intrusions.

PubMed

Scott, Samuel; Driesner, Thomas; Weis, Philipp

2015-07-27

A new and economically attractive type of geothermal resource was recently discovered in the Krafla volcanic system, Iceland, consisting of supercritical water at 450 °C immediately above a 2-km deep magma body. Although utilizing such supercritical resources could multiply power production from geothermal wells, the abundance, location and size of similar resources are undefined. Here we present the first numerical simulations of supercritical geothermal resource formation, showing that they are an integral part of magma-driven geothermal systems. Potentially exploitable resources form in rocks with a brittle-ductile transition temperature higher than 450 °C, such as basalt. Water temperatures and enthalpies can exceed 400 °C and 3 MJ kg(-1), depending on host rock permeability. Conventional high-enthalpy resources result from mixing of ascending supercritical and cooler surrounding water. Our models reproduce the measured thermal conditions of the resource discovered at Krafla. Similar resources may be widespread below conventional high-enthalpy geothermal systems.

Design of experimental system for supercritical CO2 fracturing under confining pressure conditions

NASA Astrophysics Data System (ADS)

Wang, H.; Lu, Q.; Li, X.; Yang, B.; Zheng, Y.; Shi, L.; Shi, X.

2018-03-01

Supercritical CO2 has the characteristics of low viscosity, high diffusion and zero surface tension, and it is considered as a new fluid for non-polluting and non-aqueous fracturing which can be used for shale gas development. Fracturing refers to a method of utilizing the high-pressure fluid to generate fractures in the rock formation so as to improve the oil and gas flow conditions and increase the oil and gas production. In this article, a new type of experimental system for supercritical CO2 fracturing under confining pressure conditions is designed, which is based on characteristics of supercritical CO2, shale reservoir and down-hole environment. The experimental system consists of three sub-systems, including supercritical CO2 generation system, supercritical CO2 fracturing system and data analysis system. It can be used to simulate supercritical CO2 fracturing under geo-stress conditions, thus to study the rock initiation pressure, the formation of the rock fractures, fractured surface morphology and so on. The experimental system has successfully carried out a series of supercritical CO2 fracturing experiments. The experimental results confirm the feasibility of the experimental system and the high efficiency of supercritical CO2 in fracturing tight rocks.

Supercritical Water Mixture (SCWM) Experiment

NASA Technical Reports Server (NTRS)

Hicks, Michael C.; Hegde, Uday G.

2012-01-01

The subject presentation, entitled, Supercritical Water Mixture (SCWM) Experiment, was presented at the International Space Station (ISS) Increment 33/34 Science Symposium. This presentation provides an overview of an international collaboration between NASA and CNES to study the behavior of a dilute aqueous solution of Na2SO4 (5% w) at near-critical conditions. The Supercritical Water Mixture (SCWM) investigation, serves as important precursor work for subsequent Supercritical Water Oxidation (SCWO) experiments. The SCWM investigation will be performed in DECLICs High Temperature Insert (HTI) for the purpose of studying critical fluid phenomena at high temperatures and pressures. The HTI includes a completely sealed and integrated test cell (i.e., Sample Cell Unit SCU) that will contain approximately 0.3 ml of the aqueous test solution. During the sequence of tests, scheduled to be performed in FY13, temperatures and pressures will be elevated to critical conditions (i.e., Tc = 374C and Pc = 22 MPa) in order to observe salt precipitation, precipitate agglomeration and precipitate transport in the presence of a temperature gradient without the influences of gravitational forces. This presentation provides an overview of the motivation for this work, a description of the DECLIC HTI hardware, the proposed test sequences, and a brief discussion of the scientific research objectives.

Charting the landscape of supercritical string theory.

PubMed

Hellerman, Simeon; Swanson, Ian

2007-10-26

Special solutions of string theory in supercritical dimensions can interpolate in time between theories with different numbers of spacetime dimensions and different amounts of world sheet supersymmetry. These solutions connect supercritical string theories to the more familiar string duality web in ten dimensions and provide a precise link between supersymmetric and purely bosonic string theories. Dimension quenching and c duality appear to be natural concepts in string theory, giving rise to large networks of interconnected theories.

Kern River steam expansion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rintoul, B.

1970-09-15

The newest addition to Getty Oil Co.'s imposing array of steam equipment at Kern River is a 240-million-btu-per-hr boiler. This boiler is almost 5 times more powerful than the previous largest piece of steam-generating hardware in use in the field. The huge boiler went into operation in Aug. on the Canfield Fee property on Sec. 29, 28S-28E. It is being used to furnish steam for 60 wells in a displacement project. The components that have made Getty Oil Co. the leading steamer at Kern River and the field, in turn, the world capital for oil-field steam operations include shallow wells,more » steam generators, and--since last year--a computer. There are more than 4,500 oil wells in the Kern River field, including more than 2,600 on Getty Oil properties. Getty Oil's steam operations involve 2,469 producing wells and 151 injection wells, including 2,167 producing wells in stimulation projects and 302 producing wells in displacement projects. The Kern River drilling program for 1970 consists of 313 wells of which 179 are steam-injection wells for the expansion of displacement projects. Wells are shallow, drilled mainly to the Kern River Series sands at an average depth of 900 ft, with a few drilled to the China Grade zone at an average depth of 1,300 ft. To furnish steam for the massive Kern River program, Getty Oil has assembled a force of 96 steam generators.« less

Application of supercritical fluid carbon dioxide to the extraction and analysis of lipids.

PubMed

Lee, Jae Won; Fukusaki, Eiichiro; Bamba, Takeshi

2012-10-01

Supercritical carbon dioxide (SCCO(2)) is an ecofriendly supercritical fluid that is chemically inert, nontoxic, noninflammable and nonpolluting. As a green material, SCCO(2) has desirable properties such as high density, low viscosity and high diffusivity that make it suitable for use as a solvent in supercritical fluid extraction, an effective and environment-friendly analytical method, and as a mobile phase for supercritical fluid chromatography, which facilitates high-throughput, high-resolution analysis. Furthermore, the low polarity of SCCO(2) is suitable for the extraction and analysis of hydrophobic compounds. The growing concern surrounding environmental pollution has triggered the development of green analysis methods based on the use of SCCO(2) in various laboratories and industries. SCCO(2) is becoming an effective alternative to conventional organic solvents. In this review, the usefulness of SCCO(2) in supercritical fluid extraction and supercritical fluid chromatography for the extraction and analysis of lipids is described.

Organic syntheses employing supercritical carbon dioxide as a reaction solvent

NASA Technical Reports Server (NTRS)

Barstow, Leon E. (Inventor); Ward, Glen D. (Inventor); Bier, Milan (Inventor)

1993-01-01

Chemical reactions are readily carried out using supercritical carbon dioxide as the reaction medium. Supercritical carbon dioxide is of special value as a reaction medium in reactions for synthesizing polypeptides, for sequencing polypeptides, or for amino acid analysis.

Organic syntheses employing supercritical carbon dioxide as a reaction solvent

NASA Technical Reports Server (NTRS)

Barstow, Leon E. (Inventor); Ward, Glen D. (Inventor); Bier, Milan (Inventor)

1991-01-01

Chemical reactions are readily carried out using supercritical carbon dioxide as the reaction medium. Supercritical carbon dioxide is of special value as a reaction medium in reactions for synthesizing polypeptides, for sequencing polypeptides, or for amino acid analysis.

Extraction of metals using supercritical fluid and chelate forming legand

DOEpatents

Wai, Chien M.; Laintz, Kenneth E.

1998-01-01

A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated .beta.-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated .beta.-diketone and a trialkyl phosphate, or a fluorinated .beta.-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated .beta.-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process.

Extraction of metals using supercritical fluid and chelate forming ligand

DOEpatents

Wai, C.M.; Laintz, K.E.

1998-03-24

A method of extracting metalloid and metal species from a solid or liquid material by exposing the material to a supercritical fluid solvent containing a chelating agent is described. The chelating agent forms chelates that are soluble in the supercritical fluid to allow removal of the species from the material. In preferred embodiments, the extraction solvent is supercritical carbon dioxide and the chelating agent is a fluorinated {beta}-diketone. In especially preferred embodiments the extraction solvent is supercritical carbon dioxide, and the chelating agent comprises a fluorinated {beta}-diketone and a trialkyl phosphate, or a fluorinated {beta}-diketone and a trialkylphosphine oxide. Although a trialkyl phosphate can extract lanthanides and actinides from acidic solutions, a binary mixture comprising a fluorinated {beta}-diketone and a trialkyl phosphate or a trialkylphosphine oxide tends to enhance the extraction efficiencies for actinides and lanthanides. The method provides an environmentally benign process for removing contaminants from industrial waste without using acids or biologically harmful solvents. The method is particularly useful for extracting actinides and lanthanides from acidic solutions. The chelate and supercritical fluid can be regenerated, and the contaminant species recovered, to provide an economic, efficient process. 7 figs.

Supercritical fluid processing: opportunities for new resist materials and processes

NASA Astrophysics Data System (ADS)

Gallagher-Wetmore, Paula M.; Ober, Christopher K.; Gabor, Allen H.; Allen, Robert D.

1996-05-01

Over the past two decades supercritical fluids have been utilized as solvents for carrying out separations of materials as diverse as foods, polymers, pharmaceuticals, petrochemicals, natural products, and explosives. More recently they have been used for non-extractive applications such as recrystallization, deposition, impregnation, surface modification, and as a solvent alternative for precision parts cleaning. Today, supercritical fluid extraction is being practiced in the foods and beverage industries; there are commercial plants for decaffeinating coffee and tea, extracting beer flavoring agents from hops, and separating oils and oleoresins from spices. Interest in supercritical fluid processing of polymers has grown over the last ten years, and many new purification, fractionation, and even polymerization techniques have emerged. One of the most significant motivations for applying this technology to polymers has been increased performance demands. More recently, with increasing scrutiny of traditional solvents, supercritical fluids, and in particular carbon dioxide, are receiving widespread attention as 'environmentally conscious' solvents. This paper describes several examples of polymers applications, including a few involving photoresists, which demonstrate that as next- generation advanced polymer systems emerge, supercritical fluids are certain to offer advantages as cutting edge processing tools.

Fast determination of alkylphenol ethoxylates in leafy vegetables using a modified quick, easy, cheap, effective, rugged, and safe method and ultra-high performance supercritical fluid chromatography-tandem mass spectrometry.

PubMed

Jiang, Ze-Jun; Cao, Xiao-Lin; Li, Hui; Zhang, Chan; Abd El-Aty, A M; Jin, Fen; Shao, Hua; Jin, Mao-Jun; Wang, Shan-Shan; She, Yong-Xin; Wang, Jing

2017-11-24

In the present study, a quick and sensitive method was developed for simultaneous determination of nonylphenol ethoxylates (NPxEOs) and octylphenol ethoxylates (OPxEOs) (x=2-20) in three leafy vegetables, including cabbage, lettuce, and spinach using a modified "QuEChERS" method and ultra-high performance supercritical fluid chromatography-tandem mass spectrometry (UHPSFC-MS/MS) with scheduled multiple reaction monitoring (MRM). Under optimized conditions, the 38 target analytes were analyzed within a short period of time (5 min). The linearities of the matrix-matched standard calibrations were satisfactory with coefficients of determination (R 2 )>0.99 and the limits of detection (LOD) and quantification (LOQ) were in between 0.02-0.27 and 0.18-1.75μgkg -1 , respectively. The recovery of all target analytes spiked at three (low, medium, and high) fortification levels in various leafy vegetables were ranged from 72.8-122.6% with relative standard deviation (RSD) ≤18.3%. The method was successfully applied to market samples and the target analytes were found in all monitored samples, with total concentrations of 0-8.67μgkg -1 and 15.75-95.75μgkg -1 for OPxEOs and NPxEOs (x=2-20), respectively. In conclusion, the newly developed UHPSFC-ESI-MS/MS method is rapid and versatile and could be extrapolated for qualitative and quantitative analysis of APxEOs in other leafy vegetables. Copyright © 2017 Elsevier B.V. All rights reserved.

Continuous production of biodiesel under supercritical methyl acetate conditions: Experimental investigation and kinetic model.

PubMed

Farobie, Obie; Matsumura, Yukihiko

2017-10-01

In this study, biodiesel production by using supercritical methyl acetate in a continuous flow reactor was investigated for the first time. The aim of this study was to elucidate the reaction kinetics of biodiesel production by using supercritical methyl. Experiments were conducted at various reaction temperatures (300-400°C), residence times (5-30min), oil-to-methyl acetate molar ratio of 1:40, and a fixed pressure of 20MPa. Reaction kinetics of biodiesel production with supercritical methyl acetate was determined. Finally, biodiesel yield obtained from this method was compared to that obtained with supercritical methanol, ethanol, and MTBE (methyl tertiary-butyl ether). The results showed that biodiesel yield with supercritical methyl acetate increased with temperature and time. The developed kinetic model was found to fit the experimental data well. The reactivity of supercritical methyl acetate was the lowest, followed by that of supercritical MTBE, ethanol, and methanol, under the same conditions. Copyright © 2017. Published by Elsevier Ltd.

NASA supercritical airfoils: A matrix of family-related airfoils

NASA Technical Reports Server (NTRS)

Harris, Charles D.

1990-01-01

The NASA supercritical airfoil development program is summarized in a chronological fashion. Some of the airfoil design guidelines are discussed, and coordinates of a matrix of family related supercritical airfoils ranging from thicknesses of 2 to 18 percent and over a design lift coefficient range from 0 to 1.0 are presented.

Steaming Clean

ERIC Educational Resources Information Center

Hoverson, Rick

2006-01-01

Schools can provide a cleaner, more healthful school environment by simply combining heat and water. Steam vapor systems use only tap water with no chemicals added. Low-pressure (12 psi to 65 psi) steam vapor sanitizes and deodorizes. This process can then be used safely in many situations, but is especially suited for restrooms and food-service…

DEMONSTRATION BULLETIN STEAM ENHANCED REMEDIATION STEAM TECH ENVIRONMENTAL SERVICES, INC.

EPA Science Inventory

Steam Enhanced Remediation is a process in which steam is injected into the subsurface to recover volatile and semivolatile organic contaminants. It has been applied successfully to recover contaminants from soil and aquifers and at a fractured granite site. This SITE demonstra...

Study on Trailing Edge Ramp of Supercritical Airfoil

DTIC Science & Technology

2016-03-30

7 th Asia-Pacific International Symposium on Aerospace Technology, 25 – 27 November 2015, Cairns Study on Trailing Edge Ramp of Supercritical...China Abstract Trailing edge flow control method could improve the performance of supercritical airfoil with a small modification on the original...airfoil. In this paper, a ramp of 2%~7% chord length is sliced near the trailing edge to improve airfoil performance. The trailing edge ramp is

Scour in supercritical flow

DOT National Transportation Integrated Search

1988-10-01

Scour in supercritical flow is one extreme aspect of the effects of velocity on scour. Analysis of the case of scour in a long contraction shows that if all other independent variables are kept constant (1) some finite velocity is necessary to have a...

Titania nanospheres from supercritical fluids.

PubMed

Darr, J A; Kellici, S; Rehman, I U

2005-06-01

Surfactant-coated amorphous titania nanospheres have been synthesised using templating 'water-in-supercritical carbon dioxide' emulsion droplets; the process represents a clean and controlled method for the manufacture of high-purity nanoparticles.

Use and practice of achiral and chiral supercritical fluid chromatography in pharmaceutical analysis and purification.

PubMed

Lemasson, Elise; Bertin, Sophie; West, Caroline

2016-01-01

The interest of pharmaceutical companies for complementary high-performance chromatographic tools to assess a product's purity or enhance this purity is on the rise. The high-throughput capability and economic benefits of supercritical fluid chromatography, but also the "green" aspect of CO2 as the principal solvent, render supercritical fluid chromatography very attractive for a wide range of pharmaceutical applications. The recent reintroduction of new robust instruments dedicated to supercritical fluid chromatography and the progress in stationary phase technology have also greatly benefited supercritical fluid chromatography. Additionally, it was shown several times that supercritical fluid chromatography could be orthogonal to reversed-phase high-performance liquid chromatography and could efficiently compete with it. Supercritical fluid chromatography is an adequate tool for small molecules of pharmaceutical interest: synthetic intermediates, active pharmaceutical ingredients, impurities, or degradation products. In this review, we first discuss about general chromatographic conditions for supercritical fluid chromatography analysis to better suit compounds of pharmaceutical interest. We also discuss about the use of achiral and chiral supercritical fluid chromatography for analytical purposes and the recent applications in these areas. The use of preparative supercritical fluid chromatography by pharmaceutical companies is also covered. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supercritical fluid technology for enhanced drug delivery and heterogeneous catalysis

NASA Astrophysics Data System (ADS)

Pathak, Pankaj

In recent years there has been great interest in the properties of supercritical fluids (SCFs) and applications of supercritical fluid technology in chemistry, material sciences and many other areas. In our laboratory, we have applied supercritical fluid namely CO2, as a medium for pharmaceutical processing and also for heterogeneous catalysis. The method used for pharmaceutical processing is based on the Rapid Expansion of supercritical solutions into a liquid SOLVent (RESOLV). We have used this method for the preparation of nanoparticles from various anti-inflammatory (Ibuprofen and Naproxen), anti-fungal (Amphotericin B) and anti-cancer (Paclitaxel) drugs. The anticancer drug nanoparticle formulations were further used for in vitro biological evaluation. In this dissertation, results from the preparation, characterization and biological evaluation of nanoscale drug particles are reported. The effect of experimental conditions on the properties of the nanoparticles prepared via our RESOLV method is discussed. In addition we have used supercritical CO2 as a medium for photoreduction of CO2 using dispersed TiO 2 or metal coated-TiO2 nanoparticles encapsulated in nanoscale cavities of perfluorinated ionomer membranes. These catalytic films are also stable chemically and photochemically, reusable in repeated reactions. The results from the characterization of the nanoparticles and the use of films using different catalysts are presented and discussed.

Steam Pyrolysis of Polyimides: Effects of Steam on Raw Material Recovery.

PubMed

Kumagai, Shogo; Hosaka, Tomoyuki; Kameda, Tomohito; Yoshioka, Toshiaki

2015-11-17

Aromatic polyimides (PIs) have excellent thermal stability, which makes them difficult to recycle, and an effective way to recycle PIs has not yet been established. In this work, steam pyrolysis of the aromatic PI Kapton was performed to investigate the recovery of useful raw materials. Steam pyrolysis significantly enhanced the gasification of Kapton at 900 °C, resulting in 1963.1 mL g(-1) of a H2 and CO rich gas. Simultaneously, highly porous activated carbon with a high BET surface area was recovered. Steam pyrolysis increased the presence of polar functional groups on the carbon surface. Thus, it was concluded that steam pyrolysis shows great promise as a recycling technique for the recovery of useful synthetic gases and activated carbon from PIs without the need for catalysts and organic solvents.

Reaction kinetics of cellulose hydrolysis in subcritical and supercritical water

NASA Astrophysics Data System (ADS)

Olanrewaju, Kazeem Bode

The uncertainties in the continuous supply of fossil fuels from the crisis-ridden oil-rich region of the world is fast shifting focus on the need to utilize cellulosic biomass and develop more efficient technologies for its conversion to fuels and chemicals. One such technology is the rapid degradation of cellulose in supercritical water without the need for an enzyme or inorganic catalyst such as acid. This project focused on the study of reaction kinetics of cellulose hydrolysis in subcritical and supercritical water. Cellulose reactions at hydrothermal conditions can proceed via the homogeneous route involving dissolution and hydrolysis or the heterogeneous path of surface hydrolysis. The work is divided into three main parts. First, the detailed kinetic analysis of cellulose reactions in micro- and tubular reactors was conducted. Reaction kinetics models were applied, and kinetics parameters at both subcritical and supercritical conditions were evaluated. The second major task was the evaluation of yields of water soluble hydrolysates obtained from the hydrolysis of cellulose and starch in hydrothermal reactors. Lastly, changes in molecular weight distribution due to hydrothermolytic degradation of cellulose were investigated. These changes were also simulated based on different modes of scission, and the pattern generated from simulation was compared with the distribution pattern from experiments. For a better understanding of the reaction kinetics of cellulose in subcritical and supercritical water, a series of reactions was conducted in the microreactor. Hydrolysis of cellulose was performed at subcritical temperatures ranging from 270 to 340 °C (tau = 0.40--0.88 s). For the dissolution of cellulose, the reaction was conducted at supercritical temperatures ranging from 375 to 395 °C (tau = 0.27--0.44 s). The operating pressure for the reactions at both subcritical and supercritical conditions was 5000 psig. The results show that the rate-limiting step in

Geological model of supercritical geothermal reservoir related to subduction system

NASA Astrophysics Data System (ADS)

Tsuchiya, Noriyoshi

2017-04-01

Following the Great East Japan Earthquake and the accident at the Fukushima Daiichi Nuclear power station on 3.11 (11th March) 2011, geothermal energy came to be considered one of the most promising sources of renewable energy for the future in Japan. The temperatures of geothermal fields operating in Japan range from 200 to 300 °C (average 250 °C), and the depths range from 1000 to 2000 m (average 1500 m). In conventional geothermal reservoirs, the mechanical behavior of the rocks is presumed to be brittle, and convection of the hydrothermal fluid through existing network is the main method of circulation in the reservoir. In order to minimize induced seismicity, a rock mass that is "beyond brittle" is one possible candidate, because the rock mechanics of "beyond brittle" material is one of plastic deformation rather than brittle failure. Supercritical geothermal resources could be evaluated in terms of present volcanic activities, thermal structure, dimension of hydrothermal circulation, properties of fracture system, depth of heat source, depth of brittle factures zone, dimension of geothermal reservoir. On the basis of the GIS, potential of supercritical geothermal resources could be characterized into the following four categories. 1. Promising: surface manifestation d shallow high temperature, 2 Probability: high geothermal gradient, 3 Possibility: Aseismic zone which indicates an existence of melt, 4 Potential : low velocity zone which indicates magma input. Base on geophysical data for geothermal reservoirs, we have propose adequate tectonic model of development of the supercritical geothermal reservoirs. To understand the geological model of a supercritical geothermal reservoir, granite-porphyry system, which had been formed in subduction zone, was investigated as a natural analog of the supercritical geothermal energy system. Quartz veins, hydrothermal breccia veins, and glassy veins are observed in a granitic body. The glassy veins formed at 500-550 �

Chemical Composition Analysis of Extracts from Ficus Hirta Using Supercritical Fluid

NASA Astrophysics Data System (ADS)

Deng, S. B.; Chen, J. P.; Chen, Y. Z.; Yu, C. Q.; Yang, Y.; Wu, S. H.; Chen, C. Z.

2018-05-01

Ficus hirta was extracted by supercritical carbon dioxide. The volatile chemical components of extracts were analyzed using gas chromatography-mass spectrometry (GC-MS). The percentage of products extracted by Supercritical Fluid Extraction(SFE) was 2.5%. Nineteen volatile compounds were identified. The main volatile components were Elemicin, Psoralen, Palmitic acid, Bergapten, α-Linolenic acid, Medicarpin, Retinoic Acid, Maackiain, and Squalene. The method is simple and quick, and can be used for the preliminary analysis of chemical constituents of supercritical extracts of Ficus hirta.

Horizontal steam generator thermal-hydraulics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ubra, O.; Doubek, M.

1995-09-01

Horizontal steam generators are typical components of nuclear power plants with pressure water reactor type VVER. Thermal-hydraulic behavior of horizontal steam generators is very different from the vertical U-tube steam generator, which has been extensively studied for several years. To contribute to the understanding of the horizontal steam generator thermal-hydraulics a computer program for 3-D steady state analysis of the PGV-1000 steam generator has been developed. By means of this computer program, a detailed thermal-hydraulic and thermodynamic study of the horizontal steam generator PGV-1000 has been carried out and a set of important steam generator characteristics has been obtained. Themore » 3-D distribution of the void fraction and 3-D level profile as functions of load and secondary side pressure have been investigated and secondary side volumes and masses as functions of load and pressure have been evaluated. Some of the interesting results of calculations are presented in the paper.« less

Enhancement of enzymatic saccharification of Eucalyptus globulus: steam explosion versus steam treatment.

PubMed

Martin-Sampedro, Raquel; Revilla, Esteban; Villar, Juan C; Eugenio, Maria E

2014-09-01

Steam explosion and steam pre-treatment have proved capable of enhancing enzymatic saccharification of lignocellulosic materials. However, until now, these methods had not been compared under the same operational conditions and using the same raw material. Both pre-treatments lead to increased yields in the saccharification of Eucalyptus globulus; but results have been better with steam pre-treatments, despite the more accessible surface of exploded samples. The reason for this finding could be enzymatic inhibition: steam explosion causes a more extensive extraction of hemicelluloses and releases a greater amount of degradation products which can inhibit enzymatic action. Enzymatic inhibition is also dependent on the amount and chemical structure of lignin, which was also a contributing factor to the lower enzymatic yields obtained with the most severe pre-treatment. Thus, the highest yields (46.7% glucose and 73.4% xylose yields) were obtained after two cycle of steam treatment, of 5 and 3 min, at 183°C. Copyright © 2014 Elsevier Ltd. All rights reserved.

Loss of feed flow, steam generator tube rupture and steam line break thermohydraulic experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mendler, O J; Takeuchi, K; Young, M Y

1986-10-01

The Westinghouse Model Boiler No. 2 (MB-2) steam generator test model at the Engineering Test Facility in Tampa, Florida, was reinstrumented and modified for performing a series of tests simulating steam generator accident transients. The transients simulated were: loss of feed flow, steam generator tube rupture, and steam line break events. This document presents a description of (1) the model boiler and the associated test facility, (2) the tests performed, and (3) the analyses of the test results.

Supercritical Fluid Chromatography/Fourier Transform Infrared Spectroscopy Of Food Components

NASA Astrophysics Data System (ADS)

Calvey, Elizabeth M.; Page, Samuel W.; Taylor, Larry T.

1989-12-01

Supercritical fluid (SF) technologies are being investigated extensively for applications in food processing. The number of SF-related patents issued testifies to the level of interest. Among the properties of materials at temperatures and pressures above their critical points (supercritical fluids) is density-dependent solvating power. Supercritical CO2 is of particular interest to the food industry because of its low critical temperature (31.3°C) and low toxicity. Many of the components in food matrices react or degrade at elevated temperatures and may be adversely affected by high temperature extractions. Likewise, these components may not be amenable to GC analyses. Our SF research has been in the development of methods employing supercritical fluid chromatography (SFC) and extraction (SFE) coupled to a Fourier transform infrared (FT-IR) spectrometer to investigate food composition. The effects of processing techniques on the isomeric fatty acid content of edible oils and the analysis of lipid oxidation products using SFC/FT-IR with a flow-cell interface are described.

The Invisibility of Steam

ERIC Educational Resources Information Center

Greenslade, Thomas B., Jr.

2014-01-01

Almost everyone "knows" that steam is visible. After all, one can see the cloud of white issuing from the spout of a boiling tea kettle. In reality, steam is the gaseous phase of water and is invisible. What you see is light scattered from the tiny droplets of water that are the result of the condensation of the steam as its temperature…

Steam Turbines

NASA Technical Reports Server (NTRS)

1981-01-01

Turbonetics Energy, Inc.'s steam turbines are used as power generating systems in the oil and gas, chemical, pharmaceuticals, metals and mining, and pulp and paper industries. The Turbonetics line benefited from use of NASA research data on radial inflow steam turbines and from company contact with personnel of Lewis Research Center, also use of Lewis-developed computer programs to determine performance characteristics of turbines.

STEAM GENERATOR FOR NUCLEAR REACTOR

DOEpatents

Kinyon, B.W.; Whitman, G.D.

1963-07-16

The steam generator described for use in reactor powergenerating systems employs a series of concentric tubes providing annular passage of steam and water and includes a unique arrangement for separating the steam from the water. (AEC)

Supercritical water oxidation of landfill leachate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Shuzhong, E-mail: s_z_wang@yahoo.cn; Guo Yang; Chen Chongming

2011-09-15

Highlights: > Thermal analysis of NH{sub 3} in supercritical water oxidation reaction. > Research on the catalytic reaction of landfill leachate by using response surface method. > Kinetic research of supercritical water oxidation of NH{sub 3} with and without MnO{sub 2} catalyst. - Abstract: In this paper, ammonia as an important ingredient in landfill leachate was mainly studied. Based on Peng-Robinson formulations and Gibbs free energy minimization method, the estimation of equilibrium composition and thermodynamic analysis for supercritical water oxidation of ammonia (SCWO) was made. As equilibrium is reached, ammonia could be totally oxidized in SCW. N{sub 2} is themore » main product, and the formation of NO{sub 2} and NO could be neglected. The investigation on SCWO of landfill leachate was conducted in a batch reactor at temperature of 380-500 deg. C, reaction time of 50-300 s and pressure of 25 MPa. The effect of reaction parameters such as oxidant equivalent ratio, reaction time and temperature were investigated. The results showed that COD and NH{sub 3} conversion improved as temperature, reaction time and oxygen excess increased. Compared to organics, NH{sub 3} is a refractory compound in supercritical water. The conversion of COD and NH{sub 3} were higher in the presence of MnO{sub 2} than that without catalyst. The interaction between reaction temperature and time was analyzed by using response surface method (RSM) and the results showed that its influence on the NH{sub 3} conversion was relatively insignificant in the case without catalyst. A global power-law rate expression was regressed from experimental data to estimate the reaction rate of NH{sub 3}. The activation energy with and without catalyst for NH{sub 3} oxidation were 107.07 {+-} 8.57 kJ/mol and 83.22 {+-} 15.62 kJ/mol, respectively.« less

Particle Formation and Product Formulation Using Supercritical Fluids.

PubMed

Knez, Željko; Knez Hrnčič, Maša; Škerget, Mojca

2015-01-01

Traditional methods for solids processing involve either high temperatures, necessary for melting or viscosity reduction, or hazardous organic solvents. Owing to the negative impact of the solvents on the environment, especially on living organisms, intensive research has focused on new, sustainable methods for the processing of these substances. Applying supercritical fluids for particle formation may produce powders and composites with special characteristics. Several processes for formation and design of solid particles using dense gases have been studied intensively. The unique thermodynamic and fluid-dynamic properties of supercritical fluids can be used also for impregnation of solid particles or for the formation of solid powderous emulsions and particle coating, e.g., for formation of solids with unique properties for use in different applications. We give an overview of the application of sub- and supercritical fluids as green processing media for particle formation processes and present recent advances and trends in development.

ENGINEERING BULLETIN: SUPERCRITICAL WATER OXIDATION

EPA Science Inventory

This engineering bulletin presents a description and status of supercritical water oxidation technology, a summary of recent performance tests, and the current applicability of this emerging technology. This information is provided to assist remedial project managers, contractors...

Experimental study on the liquefaction of cellulose in supercritical ethanol

NASA Astrophysics Data System (ADS)

Peng, Jinxing; Liu, Xinyuan; Bao, Zhenbo

2018-03-01

Cellulose is the major composition of solid waste for producing biofuel; cellulose liquefaction is helpful for realizing biomass supercritical liquefaction process. This paper is taking supercritical ethanol as the medium, liquefied cellulose with the intermittence installation of high press cauldron. Experiments have studied technical condition and the technology parameter of cellulose liquefaction in supercritical ethanol, and the pyrolysis mechanism was analysed based on the pyrolysis product. Results show that cellulose can be liquefied, can get good effect through appropriate technology condition. Under not catalyst, highest liquefaction rate of cellulose can reach 73.5%. The composition of the pyrolysis product was determined by GC-MS.

Large Eddy Simulation of a Supercritical Turbulent Mixing Layer

NASA Astrophysics Data System (ADS)

Sheikhi, Reza; Hadi, Fatemeh; Safari, Mehdi

2017-11-01

Supercritical turbulent flows are relevant to a wide range of applications such as supercritical power cycles, gas turbine combustors, rocket propulsion and internal combustion engines. Large eddy simulation (LES) analysis of such flows involves solving mass, momentum, energy and scalar transport equations with inclusion of generalized diffusion fluxes. These equations are combined with a real gas equation of state and the corresponding thermodynamic mixture variables. Subgrid scale models are needed for not only the conventional convective terms but also the additional high pressure effects arising due to the nonlinearity associated with generalized diffusion fluxes and real gas equation of state. In this study, LES is carried out to study the high pressure turbulent mixing of methane with carbon dioxide in a temporally developing mixing layer under supercritical condition. LES results are assessed by comparing with data obtained from direct numerical simulation (DNS) of the same layer. LES predictions agree favorably with DNS data and represent several key supercritical turbulent flow features such as high density gradient regions. Supported by DOE Grant SC0017097; computational support is provided by DOE National Energy Research Scientific Computing Center.

Supercritical fluid processing of drug nanoparticles in stable suspension.

PubMed

Pathak, Pankaj; Meziani, Mohammed J; Desai, Tarang; Foster, Charles; Diaz, Julian A; Sun, Ya-Ping

2007-07-01

Significant effort has been directed toward the development of drug formulation and delivery techniques, especially for the drug of no or poor aqueous solubility. Among various strategies to address the solubility issue, the reduction of drug particle sizes to the nanoscale has been identified as a potentially effective and broadly applicable approach. Complementary to traditional methods, supercritical fluid techniques have found unique applications in the production and processing of drug particles. Here we report the application of a newly developed supercritical fluid processing technique, Rapid Expansion of a Supercritical Solution into a Liquid Solvent, to the nanosizing of potent antiparasitic drug Amphotericin B particles. A supercritical carbon dioxide-cosolvent system was used for the solubilization and processing of the drug. The process produced well-dispersed nanoscale Amphotericin B particles suspended in an aqueous solution, and the suspension was intrinsically stable or could be further stabilized in the presence of water-soluble polymers. The properties of the drug nanoparticles were found to be dependent on the type of cosolvent used. The results on the use of dimethyl sulfoxide and methanol as cosolvents and their effects on the properties of nanosized Amphotericin B particles are presented and discussed.

Uncertainty Analysis of Heat Transfer to Supercritical Hydrogen in Cooling Channels

NASA Technical Reports Server (NTRS)

Locke, Justin M.; Landrum, D. Brian

2005-01-01

Sound understanding of the cooling efficiency of supercritical hydrogen is crucial to the development of high pressure thrust chambers for regeneratively cooled LOX/LH2 rocket engines. This paper examines historical heat transfer correlations for supercritical hydrogen and the effects of uncertainties in hydrogen property data. It is shown that uncertainty due to property data alone can be as high as 10%. Previous heated tube experiments with supercritical hydrogen are summarized, and data from a number of heated tube experiments are analyzed to evaluate conditions for which the available correlations are valid.

Coiled tubing drilling with supercritical carbon dioxide

DOEpatents

Kolle , Jack J.

2002-01-01

A method for increasing the efficiency of drilling operations by using a drilling fluid material that exists as supercritical fluid or a dense gas at temperature and pressure conditions existing at a drill site. The material can be used to reduce mechanical drilling forces, to remove cuttings, or to jet erode a substrate. In one embodiment, carbon dioxide (CO.sub.2) is used as the material for drilling within wells in the earth, where the normal temperature and pressure conditions cause CO.sub.2 to exist as a supercritical fluid. Supercritical carbon dioxide (SC--CO.sub.2) is preferably used with coiled tube (CT) drilling equipment. The very low viscosity SC--CO.sub.2 provides efficient cooling of the drill head, and efficient cuttings removal. Further, the diffusivity of SC--CO.sub.2 within the pores of petroleum formations is significantly higher than that of water, making jet erosion using SC--CO.sub.2 much more effective than water jet erosion. SC--CO.sub.2 jets can be used to assist mechanical drilling, for erosion drilling, or for scale removal. A choke manifold at the well head or mud cap drilling equipment can be used to control the pressure within the borehole, to ensure that the temperature and pressure conditions necessary for CO.sub.2 to exist as either a supercritical fluid or a dense gas occur at the drill site. Spent CO.sub.2 can be vented to the atmosphere, collected for reuse, or directed into the formation to aid in the recovery of petroleum.

Steam cooling system for a gas turbine

DOEpatents

Wilson, Ian David; Barb, Kevin Joseph; Li, Ming Cheng; Hyde, Susan Marie; Mashey, Thomas Charles; Wesorick, Ronald Richard; Glynn, Christopher Charles; Hemsworth, Martin C.

2002-01-01

The steam cooling circuit for a gas turbine includes a bore tube assembly supplying steam to circumferentially spaced radial tubes coupled to supply elbows for transitioning the radial steam flow in an axial direction along steam supply tubes adjacent the rim of the rotor. The supply tubes supply steam to circumferentially spaced manifold segments located on the aft side of the 1-2 spacer for supplying steam to the buckets of the first and second stages. Spent return steam from these buckets flows to a plurality of circumferentially spaced return manifold segments disposed on the forward face of the 1-2 spacer. Crossover tubes couple the steam supply from the steam supply manifold segments through the 1-2 spacer to the buckets of the first stage. Crossover tubes through the 1-2 spacer also return steam from the buckets of the second stage to the return manifold segments. Axially extending return tubes convey spent cooling steam from the return manifold segments to radial tubes via return elbows.

SUPERCRITICAL FLUID EXTRACTION OF POLYCYCLIC AROMATIC HYDROCARBON MIXTURES FROM CONTAMINATED SOILS

EPA Science Inventory

Highly contaminated (with PAHs) topsoils were extracted with supercritical CO₂ to determine the feasibility and mechanism of supercritical fluid extraction (SFE). Effect of SCF density, temperature, cosolvent type and amount, and of slurrying the soil with water were ...

Step-wise supercritical extraction of carbonaceous residua

DOEpatents

Warzinski, Robert P.

1987-01-01

A method of fractionating a mixture containing high boiling carbonaceous material and normally solid mineral matter includes processing with a plurality of different supercritical solvents. The mixture is treated with a first solvent of high critical temperature and solvent capacity to extract a large fraction as solute. The solute is released as liquid from solvent and successively treated with other supercritical solvents of different critical values to extract fractions of differing properties. Fractionation can be supplemented by solute reflux over a temperature gradient, pressure let down in steps and extractions at varying temperature and pressure values.

Geothermal steam condensate reinjection

NASA Technical Reports Server (NTRS)

Chasteen, A. J.

1974-01-01

Geothermal electric generating plants which use condensing turbines and generate and excess of condensed steam which must be disposed of are discussed. At the Geysers, California, the largest geothermal development in the world, this steam condensate has been reinjected into the steam reservoir since 1968. A total of 3,150,000,000 gallons of steam condensate has been reinjected since that time with no noticeable effect on the adjacent producing wells. Currently, 3,700,000 gallons/day from 412 MW of installed capacity are being injected into 5 wells. Reinjection has also proven to be a satisfactory method of disposing of geothermal condensate a Imperial Valley, California, and at the Valles Caldera, New Mexico.

Effects of Natural Osmolytes on the Protein Structure in Supercritical CO2: Molecular Level Evidence.

PubMed

Monhemi, Hassan; Housaindokht, Mohammad Reza; Nakhaei Pour, Ali

2015-08-20

Protein instability in supercritical CO2 limits the application of this green solvent in enzyme-catalyzed reactions. CO2 molecules act as a protein denaturant at high pressure under supercritical conditions. Here, for the first time, we show that natural osmolytes could stabilize protein conformation in supercritical CO2. Molecular dynamics simulation is used to monitor the effects of adding different natural osmolytes on the conformation and dynamics of chymotrypsin inhibitor 2 (CI2) in supercritical CO2. Simulations showed that CI2 is denatured at 200 bar in supercritical CO2, which is in agreement with experimental observations. Interestingly, the protein conformation remains native after addition of ∼1 M amino acid- and sugar-based osmolyte models. These molecules stabilize protein through the formation of supramolecular self-assemblies resulting from macromolecule-osmolyte hydrogen bonds. Nevertheless, trimethylamine N-oxide, which is known as a potent osmolyte for protein stabilization in aqueous solutions, amplifies protein denaturation in supercritical CO2. On the basis of our structural analysis, we introduce a new mechanism for the osmolyte effect in supercritical CO2, an "inclusion mechanism". To the best of our knowledge, this is the first study that introduces the application of natural osmolytes in a supercritical fluid and describes mechanistic insights into osmolyte action in nonaqueous media.

Supercritical Carbon Dioxide and Its Potential as a Life-Sustaining Solvent in a Planetary Environment

PubMed Central

Budisa, Nediljko; Schulze-Makuch, Dirk

2014-01-01

Supercritical fluids have different properties compared to regular fluids and could play a role as life-sustaining solvents on other worlds. Even on Earth, some bacterial species have been shown to be tolerant to supercritical fluids. The special properties of supercritical fluids, which include various types of selectivities (e.g., stereo-, regio-, and chemo-selectivity) have recently been recognized in biotechnology and used to catalyze reactions that do not occur in water. One suitable example is enzymes when they are exposed to supercritical fluids such as supercritical carbon dioxide: enzymes become even more stable, because they are conformationally rigid in the dehydrated state. Furthermore, enzymes in anhydrous organic solvents exhibit a “molecular memory”, i.e., the capacity to “remember” a conformational or pH state from being exposed to a previous solvent. Planetary environments with supercritical fluids, particularly supercritical carbon dioxide, exist, even on Earth (below the ocean floor), on Venus, and likely on Super-Earth type exoplanets. These planetary environments may present a possible habitat for exotic life. PMID:25370376

Supercritical carbon dioxide and its potential as a life-sustaining solvent in a planetary environment.

PubMed

Budisa, Nediljko; Schulze-Makuch, Dirk

2014-08-08

Supercritical fluids have different properties compared to regular fluids and could play a role as life-sustaining solvents on other worlds. Even on Earth, some bacterial species have been shown to be tolerant to supercritical fluids. The special properties of supercritical fluids, which include various types of selectivities (e.g., stereo-, regio-, and chemo-selectivity) have recently been recognized in biotechnology and used to catalyze reactions that do not occur in water. One suitable example is enzymes when they are exposed to supercritical fluids such as supercritical carbon dioxide: enzymes become even more stable, because they are conformationally rigid in the dehydrated state. Furthermore, enzymes in anhydrous organic solvents exhibit a "molecular memory", i.e., the capacity to "remember" a conformational or pH state from being exposed to a previous solvent. Planetary environments with supercritical fluids, particularly supercritical carbon dioxide, exist, even on Earth (below the ocean floor), on Venus, and likely on Super-Earth type exoplanets. These planetary environments may present a possible habitat for exotic life.

High-efficiency condenser of steam from a steam-gas mixture

NASA Astrophysics Data System (ADS)

Milman, O. O.; Krylov, V. S.; Ptakhin, A. V.; Kondratev, A. V.; Yankov, G. G.

2017-12-01

The design of a module for a high-efficiency condenser of steam with a high content (up to 15%) of noncondensable gases (NCGs) with a nearly constant steam-gas mixture (SGM) velocity during the condensation of steam has been developed. This module provides the possibility to estimate the operational efficiency of six condenser zones during the motion of steam from the inlet to the SGM suction point. Some results of the experimental tests of the pilot high-efficiency condenser module are presented. The dependence of the average heat transfer coefficient k¯ on the volumetric NCG concentration v¯ has been derived. It is shown that the high-efficiency condenser module can provide a moderate decrease in k¯ from 4400-4600 to 2600-2800 W/(m2 K) at v¯ ≈ 0.5-9.0%. The heat transfer coefficient distribution over different module zones at a heat duty close to its nominal value has been obtained. From this distribution, it can be seen that the average heat transfer coefficient decreases to 2600 W/(m2 K) at an NCG concentration v¯ = 7.5%, but the first condenser sections ( 1- 3) retain high values of k¯ at a level of no lower than 3200 W/(m2 K), and the last sections operate less well, having k¯ at a level of 1700 W/(m2 K). The dependence of the average heat transfer coefficient on the water velocity in condenser tubes has been obtained at a nearly nominal duty such that the extrapolation of this dependence to the water velocity of 2 m/s may be expected to give k¯ = 5000 W/(m2 K) for relatively pure steam, but an increase in k¯ at v¯ = 8% will be smaller. The effect of the gas removal device characteristic on the operation of the high-efficiency condenser module is described. The design developed for the steam condenser of a gas-turbine plant with a power of 25 MW, a steam flow rate of 40.2 t/h, and a CO2 concentration of up to 12% with consideration for the results of performed studies is presented.

More steam for Kern River

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rintoul, B.

1973-02-01

While production generally is declining elsewhere in California, the Kern River field continues to post gains. The field last year produced at an all-time high for the second year in a row, putting out at least 1.5 million bbl more than in its previous peak year. There is every reason to believe that gains will continue through this year. Steam is in the factor that underlies Kern River's resurgence, and Getty Oil Co., the field's premier steamer, recently added to its already imposing array of steam-generating equipment a pair of large boilers, each capable of generating 240 million btus permore » hr. Along with expansion of the steaming effort the company also expanded its water-treating facilities, making sure there will be plenty of feed water to fuel the steam generators at work in the field. The new boilers are being used to furnish steam to 136 wells in a steam displacement project. The purpose of going to a larger generator has been to gain higher efficiency. The components that have made Getty Oil the leading steamer at Kern River and the field, in turn, the world capital for oil-field steam operations include shallow wells, steam generators and--since 1969--a computer. The entire project is described in detail.« less

Simultaneous destraction and desulfurization of Illinois coals with supercritical ethanol

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, B.C.

1983-01-01

Various Illinois coals (with Illinois number6 being the main one) are liquefied with various supercritical solvents (ethanol being the main solvent) at 543-598 K, system pressures of 6.99-24.23 MPa, flow rates of 3.0-7.5 ml/min, reaction time of 0-180 minutes, and coal particle sizes of 0.36-0.85 mm to 1.00-2.36 mm to systematically investigate the effects of flow rates, reaction time, coal particle size, temperature, pressure, coal characteristics (by using different Illinois coals), supercritical medium (by using different solvents), and the addition of potassium hydroxide. The % weight loss of coal and the % sulfur removal during destraction and desulfurization of coalmore » are functions of the flow rate, the reaction time, the coal particle size, temperature, pressure and the supercritical solvent. Temperature, pressure and the supercritical medium are the most important parameters in controlling the % weight loss of coal and the % sulfur removal. The % weight loss of coal can be related to a power law and fits quite nicely into a second order kinetic model. The % sulfur removal also follows a second order kinetic model. A secondary reaction is observed during the destraction process, which implies that destraction, and possibly desulfurization, of coal is a multistep reaction including a physical extraction step where the major portion of the coal and sulfur was removed and then followed by a chemical reaction. Supercritical ethanol definitely enhances the removal of sulfur compounds from coal. The enhanced selectivity by supercritical ethanol is greatest at a pressure just above the critical pressure of ethanol. Finally, addition of a base such as potassium hydroxide enhances both % weight loss of coal and the % sulfur removal.« less

Modification of electrochemically deposited apatite using supercritical water.

PubMed

Ban, S; Hasegawa, J

2001-12-01

Supercritical water was used as a modification method of electrochemically deposited apatite on pure titanium. The apatites were coated on a commercially pure titanium plate using a hydrothermal-electrochemical method. A constant direct current at 12.5 mA/cm2 was loaded for 1 hr at 25, 60, 100, 150 and 200 degrees C in an electrolyte containing calcium and phosphate ions. The deposited apatite on the titanium substrate was stored in supercritical water at 450 degrees C under 45 MPa for 8 hr. With this treatment, the crystallinity of the apatites increased, sharp edges of the deposited apatites were rounded off, and the bonding strength of the titanium substrate to the deposited apatites significantly increased. On the other hand, weight loss in 0.01 N HCl decreased and the weight gain rate in a simulated body fluid also decreased with this treatment. It is suggested that the modification using supercritical water improved the mechanical strength of the deposited apatite, but worsened its bioactivity.

Supercritical Fluid Chromatography--Theoretical Background and Applications on Natural Products.

PubMed

Hartmann, Anja; Ganzera, Markus

2015-11-01

The use of supercritical fluid chromatography for natural product analysis as well as underlying theoretical mechanisms and instrumental requirements are summarized in this review. A short introduction focusing on the historical development of this interesting separation technique is followed by remarks on the current instrumental design, also describing possible detection modes and useable stationary phases. The overview on relevant applications is grouped based on their basic intention, may it be (semi)preparative or purely analytical. They indicate that supercritical fluid chromatography is still primarily considered for the analysis of nonpolar analytes like carotenoids, fatty acids, or terpenes. The low polarity of supercritical carbon dioxide, which is used with modifiers almost exclusively as a mobile phase today, combined with high efficiency and fast separations might explain the popularity of supercritical fluid chromatography for the analysis of these compounds. Yet, it has been shown that more polar natural products (e.g., xanthones, flavonoids, alkaloids) are separable too, with the same (if not superior) selectivity and reproducibility than established approaches like HPLC or GC. Georg Thieme Verlag KG Stuttgart · New York.

Isoprene/methyl acrylate Diels-Alder reaction in supercritical carbon dioxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, B.; Akgerman, A.

1999-12-01

The Diels-Alder reaction between isoprene and methyl acrylate was carried out in supercritical carbon dioxide in the temperature range 110--140 C and the pressure range 95.2--176.9 atm in a 300 cm{sup 3} autoclave. The high-pressure phase behavior of the reaction mixture in the vicinity of its critical region was determined in a mixed vessel with a sight window to ensure that all the experiments were performed in the supercritical single-phase region. Kinetic data were obtained at different temperatures, pressures, and reaction times. It was observed that in the vicinity of the critical point the reaction rate constant decreases with increasingmore » pressure. It was also determined that the reaction selectivity does not change with operating conditions. Transition-state theory was used to explain the effect of pressure on reaction rate and product selectivity. Additional experiments were conducted at constant temperature but different phase behaviors (two-phase region, liquid phase, supercritical phase) by adjusting the initial composition and pressure. It was shown that the highest reaction rate is in the supercritical region.« less

Treatment of municipal sewage sludge in supercritical water: A review.

PubMed

Qian, Lili; Wang, Shuzhong; Xu, Donghai; Guo, Yang; Tang, Xingying; Wang, Laisheng

2016-02-01

With increasing construction of wastewater treatment plants and stricter policies, municipal sewage sludge (MSS) disposal has become a serious problem. Treatment of MSS in supercritical water (SCW) can avoid the pre-drying procedure and secondary pollution of conventional methods. SCW treatment methods can be divided into supercritical water gasification (SCWG), supercritical water partial oxidation (SCWPO) and supercritical water oxidation (SCWO) technologies with increasing amounts of oxidants. Hydrogen-rich gases can be generated from MSS by SCWG or SCWPO technology using oxidants less than stoichiometric ratio while organic compounds can be completely degraded by SCWO technology with using an oxidant excess. For SCWG and SCWPO technologies, this paper reviews the influences of different process variables (MSS properties, moisture content, temperature, oxidant amount and catalysts) on the production of gases. For SCWO technology, this paper reviews research regarding the removal of organics with or without hydrothermal flames and the changes in heavy metal speciation and risk. Finally, typical systems for handling MSS are summarized and research needs and challenges are proposed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Solubility and conversion of carbamazepine polymorphs in supercritical carbon dioxide.

PubMed

Bettini, R; Bonassi, L; Castoro, V; Rossi, A; Zema, L; Gazzaniga, A; Giordano, F

2001-06-01

The aim of this work was to investigate whether mixtures of carbamazepine polymorphs could be processed in supercritical (SC) CO(2) in order to obtain the pure stable crystalline phase. To accomplish this goal the solubility of carbamazepine polymorphs I and III in supercritical CO(2) was first assessed using a low solvent flux dynamic method. Mixtures of Form I and Form III were processed in dynamic or static conditions in SC-CO(2). Differential scanning calorimetry, Fourier transformed infrared spectroscopy, and powder X-ray diffractometry were used to analyse solid samples in terms of polymorph composition. It was found that Form I and Form III of carbamazepine have different solubility in supercritical CO(2) at 55 degrees C above 300 bar. Due to the transformation of the metastable form, conversion of Form I into Form III can be carried out on a binary mixture of the two polymorphs by treating the mixture at 55 degrees C and 350 bar, under both static and dynamic conditions, via its solubilization in supercritical CO(2).

Supercritical Fluid Spray Application Process for Adhesives and Primers

DTIC Science & Technology

2003-03-01

The basic scheme of SFE process consists of three steps. A solvent, typically carbon dioxide, first is heated and pressurized to a supercritical...passivation step to remove contaminants and to prevent recontamination. Bok et al. (25) describe a pressure pulsation mechanism to stimulate improved...in as a liquid, and then it is heated to above its critical temperature to become a supercritical fluid. The sample is injected and dissolved into

STEAM by Design

ERIC Educational Resources Information Center

Keane, Linda; Keane, Mark

2016-01-01

We live in a designed world. STEAM by Design presents a transdisciplinary approach to learning that challenges young minds with the task of making a better world. Learning today, like life, is dynamic, connected and engaging. STEAM (Science, Technology, Environment, Engineering, Art, and Math) teaching and learning integrates information in…

Hydrogel Nanoparticles from Supercritical Technology for Pharmaceutical and Seismological Applications

NASA Astrophysics Data System (ADS)

Hemingway, Melinda Graham

This research focuses on hydrogel nanoparticle formation using miniemulsion polymerization and supercritical carbon dioxide. Hydrogel nanopowder is produced by a novel combination of inverse miniemulsion polymerization and supercritical drying (MPSD) methods. Three drying methods of miniemulsions are examined: (1) a conventional freeze drying technique, and (2) two supercritical drying techniques: (2a) supercritical fluid injection into miniemulsions, and (2b) the polymerized miniemulsion injection into supercritical fluid. Method 2b can produce non-agglomerated hydrogel nanoparticles that are free of solvent or surfactant (Chapter 2). The optimized MPSD method was applied for producing an extended release drug formulation with mucoadhesive properties. Drug nanoparticles of mesalamine, were produced using supercritical antisolvent technology and encapsulation within two hydrogels, polyacrylamide and poly(acrylic acid-co-acrylamide). The encapsulation efficiency and release profile of drug nanoparticles is compared with commercial ground mesalamine particles. The loading efficiency is influenced by morphological compatibility (Chapter 3). The MPSD method was extended for encapsulation of zinc oxide nanoparticles for UV protection in sunscreens (Chapter 4). ZnO was incorporated into the inverse miniemulsion during polymerization. The effect of process parameters are examined on absorbency of ultraviolet light and transparency of visible light. For use of hydrogel nanoparticles in a seismological application, delayed hydration is needed. Supercritical methods extend MPSD so that a hydrophobic coating can be applied on the particle surface (Chapter 5). Multiple analysis methods and coating materials were investigated to elucidate compatibility of coating material to polyacrylamide hydrogel. Coating materials of poly(lactide), poly(sulphone), poly(vinyl acetate), poly(hydroxybutyrate), Geluice 50-13, Span 80, octadecyltrichlorosilane, and perfluorobutane sulfate (PFBS

Topics in Chemical Instrumentation--An Introduction to Supercritical Fluid Chromatography: Part 1: Principles and Instrumentation.

ERIC Educational Resources Information Center

Palmieri, Margo D.

1988-01-01

Identifies the properties and characteristics of supercritical fluids. Discusses the methodology for supercritical fluid chromatography including flow rate, plate height, column efficiency, viscosity, and other factors. Reviews instruments, column types, and elution conditions. Lists supercritical fluid data for 22 compounds, mostly organic. (MVL)

Modeling Solvation in Supercritical CO2.

PubMed

Ingrosso, Francesca; Ruiz-López, Manuel F

2017-10-06

In recent decades, a microscopic understanding of solute-solvent intermolecular interactions has been key to advances in technologies based on supercritical carbon dioxide. In many cases, computational work has provided the impetus for new discoveries, shedding new light on important concepts such as the local structure around the solute in the supercritical medium, the influence of the peculiar properties of the latter on the molecular behavior of dissolved substances and, importantly, CO 2 -philicity. In this Review, the theoretical work that has been relevant to these developments is surveyed and, by presenting some crucial open questions, the possible routes to achieving further progress based on the interplay between theory and experiments is discussed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

21 CFR 880.6880 - Steam sterilizer.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Steam sterilizer. 880.6880 Section 880.6880 Food... § 880.6880 Steam sterilizer. (a) Identification. A steam sterilizer (autoclave) is a device that is intended for use by a health care provider to sterilize medical products by means of pressurized steam. (b...

Experimental study of elliptical jet from sub to supercritical conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muthukumaran, C. K.; Vaidyanathan, Aravind, E-mail: aravind7@iist.ac.in

2014-04-15

The jet mixing at supercritical conditions involves fluid dynamics as well as thermodynamic phenomena. All the jet mixing studies at critical conditions to the present date have focused only on axisymmetric jets. When the liquid jet is injected into supercritical environment, the thermodynamic transition could be well understood by considering one of the important fluid properties such as surface tension since it decides the existence of distinct boundary between the liquid and gaseous phase. It is well known that an elliptical liquid jet undergoes axis-switching phenomena under atmospheric conditions due to the presence of surface tension. The experimental investigations weremore » carried out with low speed elliptical jet under supercritical condition. Investigation of the binary component system with fluoroketone jet and N{sub 2} gas as environment shows that the surface tension force dominates for a large downstream distance, indicating delayed thermodynamic transition. The increase in pressure to critical state at supercritical temperature is found to expedite the thermodynamic transition. The ligament like structures has been observed rather than droplets for supercritical pressures. However, for the single component system with fluoroketone jet and fluoroketone environment shows that the jet disintegrates into droplets as it is subjected to the chamber conditions even for the subcritical pressures and no axis switching phenomenon is observed. For a single component system, as the pressure is increased to critical state, the liquid jet exhibits gas-gas like mixing behavior and that too without exhibiting axis-switching behavior.« less

Research activities on supercritical fluid science in food biotechnology.

PubMed

Khosravi-Darani, Kianoush

2010-06-01

This article serves as an overview, introducing the currently popular area of supercritical fluids and their uses in food biotechnology. Within each application, and wherever possible, the basic principles of the technique, as well as a description of the history, instrumentation, methodology, uses, problems encountered, and advantages over the traditional, non-supercritical methods are given. Most current commercial application of the supercritical extraction involve biologically-produced materials; the technique may be particularly relevant to the extraction of biological compounds in cases where there is a requirement for low-temperature processing, high mass-transfer rates, and negligible carrying over of the solvent into the final product. Special applications to food processing include the decaffeination of green coffee beans, the production of hops extracts, the recovery of aromas and flavors from herbs and spices, the extraction and fractionation of edible oils, and the removal of contaminants, among others. New advances, in which the extraction is combined with reaction or crystallization steps, may further increase the attractiveness of supercritical fluids in the bioprocess industries. To develop and establish a novel and effective alternative to heating treatment, the lethal action of high hydrostatic pressure CO(2) on microorganisms, with none or only a minimal heating process, has recently received a great deal of attention.

Lipidomics by Supercritical Fluid Chromatography

PubMed Central

Laboureur, Laurent; Ollero, Mario; Touboul, David

2015-01-01

This review enlightens the role of supercritical fluid chromatography (SFC) in the field of lipid analysis. SFC has been popular in the late 1980s and 1990s before almost disappearing due to the commercial success of liquid chromatography (LC). It is only 20 years later that a regain of interest appeared when new commercial instruments were introduced. As SFC is fully compatible with the injection of extracts in pure organic solvent, this technique is perfectly suitable for lipid analysis and can be coupled with either highly universal (UV or evaporative light scattering) or highly specific (mass spectrometry) detection methods. A short history of the use of supercritical fluids as mobile phase for the separation oflipids will be introduced first. Then, the advantages and drawbacks of SFC are discussed for each class of lipids (fatty acyls, glycerolipids, glycerophospholipids, sphingolipids, sterols, prenols, polyketides) defined by the LIPID MAPS consortium. PMID:26090714

Experimental study of elliptical jet from supercritical to subcritical conditions using planar laser induced fluorescence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muthukumaran, C. K.; Vaidyanathan, Aravind, E-mail: aravind7@iist.ac.in

2015-03-15

The study of fluid jet dynamics at supercritical conditions involves strong coupling between fluid dynamic and thermodynamic phenomena. Beyond the critical point, the liquid-vapor coexistence ceases to exist, and the fluid exists as a single phase known as supercritical fluid with its properties that are entirely different from liquids and gases. At the critical point, the liquids do not possess surface tension and latent heat of evaporation. Around the critical point, the fluid undergoes large changes in density and possesses thermodynamic anomaly like enhancement in thermal conductivity and specific heat. In the present work, the transition of the supercritical andmore » near-critical elliptical jet into subcritical as well as supercritical environment is investigated experimentally with nitrogen and helium as the surrounding environment. Under atmospheric condition, a liquid jet injected from the elliptical orifice exhibits axis switching phenomena. As the injection temperature increases, the axis switching length also increases. Beyond the critical temperature, the axis switching is not observed. The investigation also revealed that pressure plays a major role in determining the thermodynamic transition of the elliptical jet only for the case of supercritical jet injected into subcritical chamber conditions. At larger pressures, the supercritical jet undergoes disintegration and formation of droplets in the subcritical environment is observed. However, for supercritical jet injection into supercritical environment, the gas-gas like mixing behavior is observed.« less

Apparatus and methods of reheating gas turbine cooling steam and high pressure steam turbine exhaust in a combined cycle power generating system

DOEpatents

Tomlinson, Leroy Omar; Smith, Raub Warfield

2002-01-01

In a combined cycle system having a multi-pressure heat recovery steam generator, a gas turbine and steam turbine, steam for cooling gas turbine components is supplied from the intermediate pressure section of the heat recovery steam generator supplemented by a portion of the steam exhausting from the HP section of the steam turbine, steam from the gas turbine cooling cycle and the exhaust from the HP section of the steam turbine are combined for flow through a reheat section of the HRSG. The reheated steam is supplied to the IP section inlet of the steam turbine. Thus, where gas turbine cooling steam temperature is lower than optimum, a net improvement in performance is achieved by flowing the cooling steam exhausting from the gas turbine and the exhaust steam from the high pressure section of the steam turbine in series through the reheater of the HRSG for applying steam at optimum temperature to the IP section of the steam turbine.

Remediation of Contaminated Soils By Supercritical Carbon Dioxide Extraction

NASA Astrophysics Data System (ADS)

Ferri, A.; Zanetti, M. C.; Banchero, M.; Fiore, S.; Manna, L.

The contaminants that can be found in soils are many, inorganic, like heavy metals, as well as organic. Among the organic contaminants, oil and coal refineries are responsi- ble for several cases of soil contamination with PAHs (Polycyclic Aromatic Hydrocar- bons). Polynuclear aromatic hydrocarbons (PAHs) have toxic, carcinogenic and mu- tagenic effects. Limits have been set on the concentration of most contaminants, and growing concern is focusing on soil contamination issues. USA regulations set the maximum acceptable level of contamination by PAHs equal to 40 ppm at residential sites and 270 ppm at industrial sites. Stricter values are usually adopted in European Countries. Supercritical carbon dioxide extraction is a possible alternative technology to remove volatile organic compounds from contaminated soils. Supercritical fluid extraction (SFE) offers many advantages over conventional solvent extraction. Super- critical fluids combine gaseous properties as a high diffusion coefficient, and liquid properties as a high solvent power. The solvent power is strongly pressure-dependent near supercritical conditions: selective extractions are possible without changing the solvent. Solute can be separate from the solvent depressurising the system; therefore, it is possible to recycle the solvent and recover the contaminant. Carbon dioxide is frequently used as supercritical fluid, because it has moderate critical conditions, it is inert and available in pure form. In this work, supercritical fluid extraction technology has been used to remove a polynuclear aromatic hydrocarbon from contaminated soils. The contaminant choice for the experiment has been naphthalene since several data are available in literature. G. A. Montero et al. [1] studied soil remediation with supercrit- ical carbon dioxide extraction technology; these Authors have found that there was a mass-transfer limitation. In the extraction vessel, the mass transfer coefficient in- creases with the

Development and validation of an ultra-performance convergence chromatography method for the quality control of Angelica gigas Nakai.

PubMed

Kim, Hyo Seon; Chun, Jin Mi; Kwon, Bo-In; Lee, A-Reum; Kim, Ho Kyoung; Lee, A Yeong

2016-10-01

Ultra-performance convergence chromatography, which integrates the advantages of supercritical fluid chromatography and ultra high performance liquid chromatography technologies, is an environmentally friendly analytical method that uses dramatically reduced amounts of organic solvents. An ultra-performance convergence chromatography method was developed and validated for the quantification of decursinol angelate and decursin in Angelica gigas using a CSH Fluoro-Phenyl column (2.1 mm × 150 mm, 1.7 μm) with a run time of 4 min. The method had an improved resolution and a shorter analysis time in comparison to the conventional high-performance liquid chromatography method. This method was validated in terms of linearity, precision, and accuracy. The limits of detection were 0.005 and 0.004 μg/mL for decursinol angelate and decursin, respectively, while the limits of quantitation were 0.014 and 0.012 μg/mL, respectively. The two components showed good regression (correlation coefficient (r 2 ) > 0.999), excellent precision (RSD < 2.28%), and acceptable recoveries (99.75-102.62%). The proposed method can be used to efficiently separate, characterize, and quantify decursinol angelate and decursin in Angelica gigas and its related medicinal materials or preparations, with the advantages of a shorter analysis time, greater sensitivity, and better environmental compatibility. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimization of Root Section for Ultra-long Steam Turbine Rotor Blade

NASA Astrophysics Data System (ADS)

Hála, Jindřich; Luxa, Martin; Šimurda, David; Bobčík, Marek; Novák, Ondřej; Rudas, Bartoloměj; Synáč, Jaroslav

2018-04-01

This study presents the comparison of aerodynamic performances of two successive designs of the root profiles for the ultra-long rotor blade equipped with a straight fir-tree dovetail. Since aerodynamic and strength requirements laid upon the root section design are contradictory, it is necessary to aerodynamically optimize the design within the limits given by the foremost strength requirements. The most limiting criterion of the static strength is the size of the blade cross-section, which is determined by the number of blades in a rotor and also by the shape and size of a blade dovetail. The aerodynamic design requires mainly the zero incidence angle at the inlet of a profile and in the ideal case ensures that the load does not exceed a limit load condition. Moreover, the typical root profile cascades are transonic with supersonic exit Mach number, therefore, the shape of a suction side and a trailing edge has to respect transonic expansion of a working gas. In this paper, the two variants of root section profile cascades are compared and the aerodynamic qualities of both variants are verified using CFD simulation and two mutually independent experimental methods of measurements (optical and pneumatic).

Supercritical fluids in separation science--the dreams, the reality and the future.

PubMed

Smith, R M

1999-09-24

The last 20 years have seen an intense interest in the use of supercritical fluids in separation science. This started with the introduction of commercial instruments first for packed and then for capillary chromatography and it looked as if this would be a technique to rival gas-liquid chromatography and HPLC. The activity developed quite rapidly into packed column supercritical fluid separations then into supercritical fluid extraction. However, in recent years there has been a decline in publications. These later techniques continue to be used but are now principally applied to a limited group of applications where they offer significant advantages over alternative techniques. This review looks back over this period and analyses how these methods were developed and the fluids, detectors and applications that were examined. It suggests why many of the initial applications have vanished and why the initial apparent promise was not fulfilled. The rise and fall of supercritical fluids represents a lesson in the way analysts approach new techniques and how we might view other new separation developments at the end of this millennium. The review looks forward to the future of supercritical fluids and their role at the end of the first century of separation science. Probably the most important idea that supercritical fluids have brought to separation science is a recognition that there is unity in the separation methods and that a continuum exists from gases to liquids.

[Studies on technology of supercritical-CO2 fluid extraction for volatile oils and saikosaponins in Bupleurum chinense DC].

PubMed

Ge, F H; Li, Y; Xie, J M; Li, Q; Ma, G J; Chen, Y H; Lin, Y C; Li, X F

2000-03-01

To study the technology of supercritical-CO2 fluid extraction (SFE-CO2) for the volatile oils and saikosaponins in Bupleurum chinense. Exploring the effects of pressure, temperature, extraction time, flow rate of CO2 and entrainers on the yield of the oils and saikosaponin-contained extracts; determining the optimum conditions for SFE-CO2; analyzing the oils by GC/MS and comparing the technology of SFE-CO2 with that of traditional steam distillation. The optimum extraction conditions turned out to be--for volatile oils: pressure (EP) = 20 MPa, temperature (ET) = 30 degrees C, isolator I pressure (1P-I) = 12 MPa, temperature(1T-I) = 65 degrees C, isolator II pressure (1P-II) = 6 MPa, temperature (1T-II) = 40 degrees C, extraction time = 4 hours, and CO2 flow rate = 10-20 kg.(h.kg)-1 crude drug; for saikosaponins: EP = 30 MPa, ET = 65 degrees C, 1P I = 12 MPa, 1T I = 55 degrees C, 1P II = 6 MPa, 1T II = 43 degrees C, extraction time = 3 hours, entrainer = 60% ethanol, and CO2 flow rate = 20-25 kg.(h.kg)-1 crude drug. SFE-CO2 excels the traditional steam distillation in raising yield and reducing extraction time. The oils are composed of 22 constituents including caproaldehyde, and the saikosaponins can only be extracted with the help of entrainers under higher pressure and temperature.

Downhole steam quality measurement

DOEpatents

Lee, David O.; Montoya, Paul C.; Muir, James F.; Wayland, Jr., J. Robert

1987-01-01

An empirical method for the remote sensing of steam quality that can be easily adapted to downhole steam quality measurements by measuring the electrical properties of two-phase flow across electrode grids at low frequencies.

Plasma microreactor in supercritical xenon and its application to diamondoid synthesis

NASA Astrophysics Data System (ADS)

Oshima, F.; Stauss, S.; Ishii, C.; Pai, D. Z.; Terashima, K.

2012-10-01

The generation of plasmas in a microreactor is demonstrated in xenon from atmospheric pressure up to supercritical conditions. Ac high voltage at a frequency of 15 kHz was applied across a 25-µm discharge gap between a tungsten wire and a fused silica micro-capillary tube in a coaxial configuration. Using this continuous flow supercritical fluid microreactor, it was possible to synthesize diamantane and other diamondoids up to nonamantane, using adamantane as a precursor and seed. It is anticipated that plasmas generated in supercritical fluid microreactors may not only allow faster fabrication of diamondoids, but also offer opportunities for the fabrication of other nanomaterials.

Supercritical-fluid extraction and chromatography-mass spectrometry for analysis of mycotoxins

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, R.D.; Udseth, H.R.

1982-07-01

The use of direct supercritical-fluid injection-mass spectrometry for the rapid analysis of mycotoxins of the tricothecene group is demonstrated. A solution containing diacetoxyscirpenol or T-2 toxin is injected into a fluid consisting primarily of pentane or carbon dioxide and is rapidly brought to supercritical conditions. Direct injection of the fluid stream into a chemical ionization source allows thermally labile compounds to be analyzed. Under these conditions trichothecene mass spectra showing significant (M + 1)/sup +/ ions and distinctive fragmentation patterns are obtained. Detection limits are in the subnanogram range. Direct analysis from complex substrates using selective supercritical-fluid extraction is proposed.more » 4 figures.« less

Solid-state chemistry and particle engineering with supercritical fluids in pharmaceutics.

PubMed

Pasquali, Irene; Bettini, Ruggero; Giordano, Ferdinando

2006-03-01

The present commentary aims to review the modern and innovative strategies in particle engineering by the supercritical fluid technologies and it is principally concerned with the aspects of solid-state chemistry. Supercritical fluids based processes for particle production have been proved suitable for controlling solid-state, morphology and particle size of pharmaceuticals, in some cases on an industrial scale. Supercritical fluids should be considered in a prominent position in the development processes of drug products for the 21st century. In this respect, this innovative technology will help in meeting the more and more stringent requirements of regulatory authorities in terms of solid-state characterisation and purity, and environmental acceptability.

Hyphenation of ultra high performance supercritical fluid chromatography with atmospheric pressure chemical ionisation high resolution mass spectrometry: Part 1. Study of the coupling parameters for the analysis of natural non-polar compounds.

PubMed

Duval, Johanna; Colas, Cyril; Pecher, Virginie; Poujol, Marion; Tranchant, Jean-François; Lesellier, Eric

2017-08-04

An analytical method based on Ultra-High-Performance Supercritical Fluid Chromatography (UHPSFC) coupled with Atmospheric Pressure Chemical Ionization - High-resolution mass spectrometry (APCI-Q-TOF-HRMS) was developed for compounds screening from oily samples. The hyphenation was made using a commercial UHPLC device coupled to a CO 2 pump in order to perform the chromatographic analysis. An adaptation of the injection system for compressible fluids was accomplished for this coupling: this modification of the injection sequence was achieved to prevent unusual variations of the injected volume related to the use of a compressible fluid. UHPSFC-HRMS hyphenation was optimized to enhance the response of the varied compounds from a seed extract (anthraquinones, free fatty acids, diacylglycerols, hydroxylated triacylglycerols and triacylglycerols). No split was used prior to the APCI ionization source, allowing introducing all the compounds in the spectrometer, ensuring a better sensitivity for minor compounds. The effects of a mechanical make-up (T-piece) added before this ionization source was discussed in terms of standard deviation of response, response intensity and fragmentation percentage. The location of the T-piece with regards to the backpressure regulator (BPR), the flow rate and the nature of the make-up solvent were studied. Results show that the effects of the studied parameters depend on the nature of the compounds, whereas the make-up addition favours the robustness of the mass response (quantitative aspect). Copyright © 2017 Elsevier B.V. All rights reserved.

Using supercritical fluids to refine hydrocarbons

DOEpatents

Yarbro, Stephen Lee

2014-11-25

This is a method to reactively refine hydrocarbons, such as heavy oils with API gravities of less than 20.degree. and bitumen-like hydrocarbons with viscosities greater than 1000 cp at standard temperature and pressure using a selected fluid at supercritical conditions. The reaction portion of the method delivers lighter weight, more volatile hydrocarbons to an attached contacting device that operates in mixed subcritical or supercritical modes. This separates the reaction products into portions that are viable for use or sale without further conventional refining and hydro-processing techniques. This method produces valuable products with fewer processing steps, lower costs, increased worker safety due to less processing and handling, allow greater opportunity for new oil field development and subsequent positive economic impact, reduce related carbon dioxide, and wastes typical with conventional refineries.

Supercritical Wing Technology: A Progress Report on Flight Evaluations

NASA Technical Reports Server (NTRS)

1972-01-01

The papers in this compilation were presented at the NASA Symposium on "Supercritical Wing Technology: A Progress Report on Flight Evaluation" held at the NASA Flight Research Center, Edwards, Calif., on February 29, 1972. The purpose of the symposium was to present timely information on flight results obtained with the F-8 and T-2C supercritical wing configurations, discuss comparisons with wind-tunnel predictions, and project [ ] flight programs planned for the F-8 and F-III (TACT) airplanes.

Buffet characteristics of the F-8 supercritical wing airplane

NASA Technical Reports Server (NTRS)

Deangelis, V. M.; Monaghan, R. C.

1977-01-01

The buffet characteristics of the F-8 supercritical wing airplane were investigated. Wing structural response was used to determine the buffet characteristics of the wing and these characteristics are compared with wind tunnel model data and the wing flow characteristics at transonic speeds. The wingtip accelerometer was used to determine the buffet onset boundary and to measure the buffet intensity characteristics of the airplane. The effects of moderate trailing edge flap deflections on the buffet onset boundary are presented. The supercritical wing flow characteristics were determined from wind tunnel and flight static pressure measurements and from a dynamic pressure sensor mounted on the flight test airplane in the vicinity of the shock wave that formed on the upper surface of the wing at transonic speeds. The comparison of the airplane's structural response data to the supercritical flow characteristics includes the effects of a leading edge vortex generator.

Formation of indomethacin-saccharin cocrystals using supercritical fluid technology.

PubMed

Padrela, Luis; Rodrigues, Miguel A; Velaga, Sitaram P; Matos, Henrique A; de Azevedo, Edmundo Gomes

2009-08-12

The main objective of the present work is to check the feasibility of supercritical fluid (SCF) technologies in the screening and design of cocrystals (novel crystalline solids). The cocrystal formation tendencies in three different SCF techniques, focusing on distinct supercritical fluid properties - solvent, anti-solvent and atomization enhancer - were investigated. The effect of processing parameters on the cocrystal formation behaviour and particle properties in these techniques was also studied. A recently reported indomethacin-saccharin (IND-SAC) cocrystalline system was our model system. A 1:1 molar ratio of indomethacin (gamma-form) and saccharin was used as a starting material. The SCF techniques employed in the study include the CSS technique (cocrystallization with supercritical solvent), the SAS technique (supercritical anti-solvent), and the AAS technique (atomization and anti-solvent). The resulting cocrystalline phase was identified using differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier transform-Raman (FT-Raman). The particle morphologies and size distributions were determined using scanning electron microscopy (SEM) and aerosizer, respectively. The pure IND-SAC cocrystals were obtained from SAS and AAS processes, whilst partial to no cocrystal formation occurred in the CSS process. However, no remarkable differences were observed in terms of cocrystal formation at different processing conditions in SAS and AAS processes. Particles from CSS processes were agglomerated and large, whilst needle-to-block-shaped and spherical particles were obtained from SAS and AAS processes, respectively. The particle size distribution of these particles was 0.2-5microm. Particulate IND-SAC cocrystals with different morphologies and sizes (nano-to-micron) were produced using supercritical fluid techniques. This work demonstrates the potential of SCF technologies as screening methods for cocrystals with possibilities for particle

Dehydrating and Sterilizing Wastes Using Supercritical CO2

NASA Technical Reports Server (NTRS)

Brown, Ian J.

2006-01-01

A relatively low-temperature process for dehydrating and sterilizing biohazardous wastes in an enclosed life-support system exploits (1) the superior mass-transport properties of supercritical fluids in general and (2) the demonstrated sterilizing property of supercritical CO2 in particular. The wastes to be treated are placed in a chamber. Liquid CO2, drawn from storage at a pressure of 850 psi (approx.=5.9 MPa) and temperature of 0 C, is compressed to pressure of 2 kpsi (approx.=14 MPa) and made to flow into the chamber. The compression raises the temperature to 10 C. The chamber and its contents are then further heated to 40 C, putting the CO2 into a supercritical state, in which it kills microorganisms in the chamber. Carrying dissolved water, the CO2 leaves the chamber through a back-pressure regulator, through which it is expanded back to the storage pressure. The expanded CO2 is refrigerated to extract the dissolved water as ice, and is then returned to the storage tank at 0 C

Helicity in supercritical temporal mixing layers

NASA Technical Reports Server (NTRS)

Bellan, J.; Okong'o, N.

2003-01-01

Databases of transitional states obtained from Direct Numerical Simulations (DNS) of temporal, supercritical mixing layers for two species systems, 02/H2 and C7Hle/N2, are analyzed to elucidate species-specific turbulence aspects.

Historical background and design evolution of the transonic aircraft technology supercritical wing

NASA Technical Reports Server (NTRS)

Ayers, T. G.; Hallissy, J. B.

1981-01-01

Two dimensional wind tunnel test results obtained for supercritical airfoils indicated that substantial improvements in aircraft performance at high subsonic speeds could be achieved by shaping the airfoil to improve the supercritical flow above the upper surface. Significant increases in the drag divergence Mach number, the maximum lift coefficient for buffer onset, and the Mach number for buffet onset at a given lift coefficient were demonstrated for the supercritical airfoil, as compared with a NACA 6 series airfoil of comparable thickness. These trends were corroborated by results from three dimensional wind tunnel and flight tests. Because these indicated extensions of the buffet boundaries could provide significant improvements in the maneuverability of a fighter airplane, an exploratory wind tunnel investigation was initiated which demonstrated that significant aerodynamic improvements could be achieved from the direct substitution of a supercritical airfoil on a variable wing sweep multimission airplane model.

Safety Picks up "STEAM"

ERIC Educational Resources Information Center

Roy, Ken

2016-01-01

This column shares safety information for the classroom. STEAM subjects--science, technology, engineering, art, and mathematics--are essential for fostering students' 21st-century skills. STEAM promotes critical-thinking skills, including analysis, assessment, categorization, classification, interpretation, justification, and prediction, and are…

Cyclic steaming in heavy oil diatomite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, M.; Beatty, F.D.

1995-12-31

Chevron currently uses cyclic steaming as a recovery method to produce economically its heavy oil diatomite resource in the Cymric field, San Joaquin Valley, California. A highly instrumented, cyclically steaming well from this field was simulated in this study to delineate important production mechanisms, to optimize operations, and to improve reservoir management. The model was constrained, as much as possible, by the available measured data. Results show that fluid flow from the well to the reservoir is primarily through the hydraulic fracture induced by the injected steam. Parameters with unique importance to modeling cyclic steaming in diatomites are: (1) inducedmore » fracture dimension (length and height), (2) matrix permeability, (3) oil/water capillary pressure, (4) grid size perpendicular to fracture face, and (5) producing bottomhole pressures. Additionally, parameters important for conventional steam injection processes, such as relative permeabilities and injected steam volume, quality, and rate, are important for diatomites also. Oil production rates and steam/oil ratios calculated by this model compare reasonably with field data.« less

Enhanced mechanical, thermal, and electric properties of graphene aerogels via supercritical ethanol drying and high-temperature thermal reduction.

PubMed

Cheng, Yehong; Zhou, Shanbao; Hu, Ping; Zhao, Guangdong; Li, Yongxia; Zhang, Xinghong; Han, Wenbo

2017-05-03

Graphene aerogels with high surface areas, ultra-low densities and thermal conductivities have been prepared to exploit their wide applications from pollution adsorption to energy storage, supercapacitor, and thermal insulation. However, the low mechanical properties, poor thermal stability and electric conductivity restrict these aerogels' applications. In this paper, we prepared mechanically strong graphene aerogels with large BET surface areas, low thermal conductivities, high thermal stability and electric conductivities via hydrothermal reduction and supercritical ethanol drying. Annealing at 1500 °C resulted in slightly increased thermal conductivity and further improvement in mechanical properties, oxidation temperature and electric conductivity of the graphene aerogel. The large BET surface areas, together with strong mechanical properties, low thermal conductivities, high thermal stability and electrical conductivities made these graphene aerogels feasible candidates for use in a number of fields covering from batteries to sensors, electrodes, lightweight conductor and insulation materials.

Steam jet mill-a prospective solution to industrial exhaust steam and solid waste.

PubMed

Zhang, Mingxing; Chen, Haiyan

2018-04-20

Bulk industrial solid wastes occupy a lot of our resources and release large amounts of toxic and hazardous substances to the surrounding environment, demanding innovative strategies for grinding, classification, collection, and recycling for economically ultrafine powder. A new technology for grinding, classification, collection, and recycling solid waste is proposed, using the superheated steam produced from the industrial exhaust steam to disperse, grind, classify, and collect the industrial solid waste. A large-scale steam jet mill was designed to operate at an inlet steam temperature 230-300 °C and an inlet pressure of 0.2-0.6 MPa. A kind of industrial solid waste fluidized-bed combustion ashes was used to grinding tests at different steam temperatures and inlet pressures. The total process for grinding, classification, and collection is drying. Two kinds of particle sizes are obtained. One particle size is d 50  = 4.785 μm, and another particle size is d 50  = 8.999 μm. For particle size d 50  = 8.999 μm, the inlet temperature is 296 °C and an inlet pressure is 0.54 MPa for the grinding chamber. The steam flow is 21.7 t/h. The yield of superfine powder is 73 t/h. The power consumption is 3.76 kW h/t. The obtained superfine powder meets the national standard S95 slag. On the basis of these results, a reproducible and sustainable industrial ecological protocol using steam produced by industrial exhaust heat coupled to solid waste recycling is proposed, providing an efficient, large-scale, low-cost, promising, and green method for both solid waste recovery and industrial exhaust heat reutilization.

49 CFR 229.105 - Steam generator number.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Steam generator number. 229.105 Section 229.105..., DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Steam Generators § 229.105 Steam generator number. An identification number shall be marked on the steam generator's...

[Supercritical and near-critical fluid solvents assisted reaction and separation processes].

PubMed

Song, R; Zeng, J; Zhong, B

2001-11-01

The tunability of supercritical and near-critical fluid (S/NCF) solvents offers environmental improvements and economic advantages from improved performances and flexibility for separation and reaction processes through density changes or cosolvents. The paper reviews the sustainable reaction and separation processes in S/NCF solvents such as supercritical carbon dioxide and near-critical water.

Preparation and Physicochemical Properties of Vinblastine Microparticles by Supercritical Antisolvent Process

PubMed Central

Zhang, Xiaonan; Zhao, Xiuhua; Zu, Yuangang; Chen, Xiaoqiang; Lu, Qi; Ma, Yuliang; Yang, Lei

2012-01-01

The objective of the study was to prepare vinblastine microparticles by supercritical antisolvent process using N-methyl-2-pyrrolidone as solvent and carbon dioxide as antisolvent and evaluate its physicochemical properties. The effects of four process variables, pressure, temperature, drug concentration and drug solution flow rate, on drug particle formation during the supercritical antisolvent process, were investigated. Particles with a mean particle size of 121 ± 5.3 nm were obtained under the optimized process conditions (precipitation temperature 60 °C, precipitation pressure 25 MPa, vinblastine concentration 2.50 mg/mL and vinblastine solution flow rate 6.7 mL/min). The vinblastine was characterized by scanning electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, mass spectrometry and dissolution test. It was concluded that physicochemical properties of crystalline vinblastine could be improved by physical modification, such as particle size reduction and generation of amorphous state using the supercritical antisolvent process. Furthermore, the supercritical antisolvent process was a powerful methodology for improving the physicochemical properties of vinblastine. PMID:23202916

Rhabdomyolysis and exercise-associated hyponatremia in ultra-bikers and ultra-runners.

PubMed

Chlíbková, Daniela; Knechtle, Beat; Rosemann, Thomas; Tomášková, Ivana; Novotný, Jan; Žákovská, Alena; Uher, Tomáš

2015-01-01

Exercise-associated hyponatremia (EAH), rhabdomyolysis and renal failure appear to be a unique problem in ultra-endurance racers. We investigated the combined occurrence of EAH and rhabdomyolysis in seven different ultra-endurance races and disciplines (i.e. multi-stage mountain biking, 24-h mountain biking, 24-h ultra-running and 100-km ultra-running). Two (15.4%) ultra-runners (man and woman) from hyponatremic ultra-athletes (n = 13) and four (4%) ultra-runners (four men) from the normonatremic group (n = 100) showed rhabdomyolysis following elevated blood creatine kinase (CK) levels > 10,000 U/L without the development of renal failure and the necessity of a medical treatment. Post-race creatine kinase, plasma and urine creatinine significantly increased, while plasma [Na(+)] and creatine clearance decreased in hyponatremic and normonatremic athletes, respectively. The percentage increase of CK was higher in the hyponatremic compared to the normonatremic group (P < 0.05). Post-race CK levels were higher in ultra-runners compared to mountain bikers (P < 0.01), in faster normonatremic (P < 0.05) and older and more experienced hyponatremic ultra-athletes (P < 0.05). In all finishers, pre-race plasma [K(+)] was related to post-race CK (P < 0.05). Hyponatremic ultra-athletes tended to develop exercise-induced rhabdomyolysis more frequently than normonatremic ultra-athletes. Ultra-runners tended to develop rhabdomyolysis more frequently than mountain bikers. We found no association between post-race plasma [Na(+)] and CK concentration in both hypo- and normonatremic ultra-athletes.

High-resolution imaging of the supercritical antisolvent process

NASA Astrophysics Data System (ADS)

Bell, Philip W.; Stephens, Amendi P.; Roberts, Christopher B.; Duke, Steve R.

2005-06-01

A high-magnification and high-resolution imaging technique was developed for the supercritical fluid antisolvent (SAS) precipitation process. Visualizations of the jet injection, flow patterns, droplets, and particles were obtained in a high-pressure vessel for polylactic acid and budesonide precipitation in supercritical CO2. The results show two regimes for particle production: one where turbulent mixing occurs in gas-like plumes, and another where distinct droplets were observed in the injection. Images are presented to demonstrate the capabilities of the method for examining particle formation theories and for understanding the underlying fluid mechanics, thermodynamics, and mass transport in the SAS process.

Effect of essential oil and supercritical carbon dioxide extract from the root of Angelica gigas on human EEG activity.

PubMed

Sowndhararajan, Kandhasamy; Seo, Min; Kim, Minju; Kim, Heeyeon; Kim, Songmun

2017-08-01

The present study aimed to investigate the effect of inhalation of essential oil (EO) and supercritical carbon dioxide extract (SC-CO 2 ) from the root of A. gigas on human electroencephalographic (EEG) activity. For this purpose, the EO was obtained from the root of A. gigas by steam distillation and SC-CO 2 was obtained at 50 °C and 400 bar for 1 h. The EEG readings were recorded using the QEEG-8 system from 8 electrode sites according to the International 10-20 system. In the EEG study, the absolute low beta (left temporal and left parietal) activity significantly increased during the inhalation of EO. In the case of SC-CO 2 inhalation, there was no significant change in absolute waves. The results revealed that the EO of A. gigas root produced significant changes in the absolute low beta activity and these changes may enhance the language learning abilities of human brain. Copyright © 2017. Published by Elsevier Ltd.

Widom line, dynamical crossover, and percolation transition of supercritical oxygen via molecular dynamics simulations.

PubMed

Raman, Abhinav S; Li, Huiyong; Chiew, Y C

2018-01-07

Supercritical oxygen, a cryogenic fluid, is widely used as an oxidizer in jet propulsion systems and is therefore of paramount importance in gaining physical insights into processes such as transcritical and supercritical vaporization. It is well established in the scientific literature that the supercritical state is not homogeneous but, in fact, can be demarcated into regions with liquid-like and vapor-like properties, separated by the "Widom line." In this study, we identified the Widom line for oxygen, constituted by the loci of the extrema of thermodynamic response functions (heat capacity, volumetric thermal expansion coefficient, and isothermal compressibility) in the supercritical region, via atomistic molecular dynamics simulations. We found that the Widom lines derived from these response functions all coincide near the critical point until about 25 bars and 15-20 K, beyond which the isothermal compressibility line begins to deviate. We also obtained the crossover from liquid-like to vapor-like behavior of the translational diffusion coefficient, shear viscosity, and rotational relaxation time of supercritical oxygen. While the crossover of the translational diffusion coefficient and shear viscosity coincided with the Widom lines, the rotational relaxation time showed a crossover that was largely independent of the Widom line. Further, we characterized the clustering behavior and percolation transition of supercritical oxygen molecules, identified the percolation threshold based on the fractal dimension of the largest cluster and the probability of finding a cluster that spans the system in all three dimensions, and found that the locus of the percolation threshold also coincided with the isothermal compressibility Widom line. It is therefore clear that supercritical oxygen is far more complex than originally perceived and that the Widom line, dynamical crossovers, and percolation transitions serve as useful routes to better our understanding of the

Widom line, dynamical crossover, and percolation transition of supercritical oxygen via molecular dynamics simulations

NASA Astrophysics Data System (ADS)

Raman, Abhinav S.; Li, Huiyong; Chiew, Y. C.

2018-01-01

Supercritical oxygen, a cryogenic fluid, is widely used as an oxidizer in jet propulsion systems and is therefore of paramount importance in gaining physical insights into processes such as transcritical and supercritical vaporization. It is well established in the scientific literature that the supercritical state is not homogeneous but, in fact, can be demarcated into regions with liquid-like and vapor-like properties, separated by the "Widom line." In this study, we identified the Widom line for oxygen, constituted by the loci of the extrema of thermodynamic response functions (heat capacity, volumetric thermal expansion coefficient, and isothermal compressibility) in the supercritical region, via atomistic molecular dynamics simulations. We found that the Widom lines derived from these response functions all coincide near the critical point until about 25 bars and 15-20 K, beyond which the isothermal compressibility line begins to deviate. We also obtained the crossover from liquid-like to vapor-like behavior of the translational diffusion coefficient, shear viscosity, and rotational relaxation time of supercritical oxygen. While the crossover of the translational diffusion coefficient and shear viscosity coincided with the Widom lines, the rotational relaxation time showed a crossover that was largely independent of the Widom line. Further, we characterized the clustering behavior and percolation transition of supercritical oxygen molecules, identified the percolation threshold based on the fractal dimension of the largest cluster and the probability of finding a cluster that spans the system in all three dimensions, and found that the locus of the percolation threshold also coincided with the isothermal compressibility Widom line. It is therefore clear that supercritical oxygen is far more complex than originally perceived and that the Widom line, dynamical crossovers, and percolation transitions serve as useful routes to better our understanding of the

Non-equilibrium condensation of supercritical carbon dioxide in a converging-diverging nozzle

NASA Astrophysics Data System (ADS)

Ameli, Alireza; Afzalifar, Ali; Turunen-Saaresti, Teemu

2017-03-01

Carbon dioxide (CO2) is a promising alternative as a working fluid for future energy conversion and refrigeration cycles. CO2 has low global warming potential compared to refrigerants and supercritical CO2 Brayton cycle ought to have better efficiency than today’s counter parts. However, there are several issues concerning behaviour of supercritical CO2 in aforementioned applications. One of these issues arises due to non-equilibrium condensation of CO2 for some operating conditions in supercritical compressors. This paper investigates the non-equilibrium condensation of carbon dioxide in the course of an expansion from supercritical stagnation conditions in a converging-diverging nozzle. An external look-up table was implemented, using an in-house FORTRAN code, to calculate the fluid properties in supercritical, metastable and saturated regions. This look-up table is coupled with the flow solver and the non-equilibrium condensation model is introduced to the solver using user defined expressions. Numerical results are compared with the experimental measurements. In agreement with the experiment, the distribution of Mach number in the nozzle shows that the flow becomes supersonic in upstream region near the throat where speed of sound is minimum also the equilibrium reestablishment occurs at the outlet boundary condition.

[Supercritical CO2 extraction and component analysis of Aesculus wilsonii seed oil].

PubMed

Chen, Guang-Yu; Shi, Zhao-Hua; Li, Hai-Chi; Ge, Fa-Huan; Zhan, Hua-Shu

2013-03-01

To research the optimal extraction process of supercritical CO2 extraction and analyze the component of the oil extracted from Aesculus wilsonii seed. Using the yield of Aesculus wilsonii seed oil as the index, optimized supercritical CO2 extraction parameter by orthogonal experiment methodology and analysed the compounds of Aesculus wilsonii seed oil by GC-MS. The optimal parameters of the supercritical CO2 extraction of the oil extracted from Aesculus wilsoniit seed were determined: the extraction pressure was 28 MPa and the temperature was 38 degrees C, the separation I pressure was 12 MPa and the temperature was 40 degrees C, the separation II pressure was 5 MPa and the temperature was 40 degrees C, the extraction time was 110 min. The average extraction rate of Aesculus wilsonii seed oil was 1.264%. 26 kinds of compounds were identified by GC-MS in Aesculus wilsonii seed oil extracted by supercritical CO2. The main components were fatty acids. Comparing with the petroleum ether extraction, the supercritical CO2 extraction has higher extraction rate, shorter extraction time, more clarity oil. The kinds of fatty acids with high amounts in Aesculus wilsonii seed oil is identical in general, the kinds of fatty acids with low amounts in Aesculus wilsonii seed oil have differences.

Supercritical Brayton Cycle Nuclear Power System Concepts

NASA Astrophysics Data System (ADS)

Wright, Steven A.

2007-01-01

Both the NASA and DOE have programs that are investigating advanced power conversion cycles for planetary surface power on the moon or Mars, and for next generation nuclear power plants on earth. The gas Brayton cycle offers many practical solutions for space nuclear power systems and was selected as the nuclear power system of choice for the NASA Prometheus project. An alternative Brayton cycle that offers high efficiency at a lower reactor coolant outlet temperature is the supercritical Brayton cycle (SCBC). The supercritical cycle is a true Brayton cycle because it uses a single phase fluid with a compressor inlet temperature that is just above the critical point of the fluid. This paper describes the use of a supercritical Brayton cycle that achieves a cycle efficiency of 26.6% with a peak coolant temperature of 750 K and for a compressor inlet temperature of 390 K. The working fluid uses a clear odorless, nontoxic refrigerant C318 perflurocarbon (C4F8) that always operates in the gas phase. This coolant was selected because it has a critical temperature and pressure of 388.38 K and 2.777 MPa. The relatively high critical temperature allows for efficient thermal radiation that keeps the radiator mass small. The SCBC achieves high efficiency because the loop design takes advantage of the non-ideal nature of the coolant equation of state just above the critical point. The lower coolant temperature means that metal fuels, uranium oxide fuels, and uranium zirconium hydride fuels with stainless steel, ferretic steel, or superalloy cladding can be used with little mass penalty or reduction in cycle efficiency. The reactor can use liquid-metal coolants and no high temperature heat exchangers need to be developed. Indirect gas cooling or perhaps even direct gas cooling can be used if the C4F8 coolant is found to be sufficiently radiation tolerant. Other fluids can also be used in the supercritical Brayton cycle including Propane (C3H8, Tcritical = 369 K) and Hexane (C6

Initial instability of round liquid jet at subcritical and supercritical environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muthukumaran, C. K.; Vaidyanathan, Aravind, E-mail: aravind7@iist.ac.in

2016-07-15

In the present experimental work, the behavior of laminar liquid jet in its own vapor as well as supercritical fluid environment is conducted. Also the study of liquid jet injection into nitrogen (N{sub 2}) environment is carried out at supercritical conditions. It is expected that the injected liquid jet would undergo thermodynamic transition to the chamber condition and this would alter the behavior of the injected jet. Moreover at such conditions there is a strong dependence between thermodynamic and fluid dynamic processes. Thus the thermodynamic transition has its effect on the initial instability as well as the breakup nature ofmore » the injected liquid jet. In the present study, the interfacial disturbance wavelength, breakup characteristics, and mixing behavior are analysed for the fluoroketone liquid jet that is injected into N{sub 2} environment as well as into its own vapor at subcritical to supercritical conditions. It is observed that at subcritical chamber conditions, the injected liquid jet exhibits classical liquid jet characteristics with Rayleigh breakup at lower Weber number and Taylor breakup at higher Weber number for both N{sub 2} and its own environment. At supercritical chamber conditions with its own environment, the injected liquid jet undergoes sudden thermodynamic transition to chamber conditions and single phase mixing characteristics is observed. However, the supercritical chamber conditions with N{sub 2} as ambient fluid does not have significant effect on the thermodynamic transition of the injected liquid jet.« less

Fast copper extraction from printed circuit boards using supercritical carbon dioxide.

PubMed

Calgaro, C O; Schlemmer, D F; da Silva, M D C R; Maziero, E V; Tanabe, E H; Bertuol, D A

2015-11-01

Technological development and intensive marketing support the growth in demand for electrical and electronic equipment (EEE), for which printed circuit boards (PCBs) are vital components. As these devices become obsolete after short periods, waste PCBs present a problem and require recycling. PCBs are composed of ceramics, polymers, and metals, particularly Cu, which is present in highest percentages. The aim of this study was to develop an innovative method to recover Cu from the PCBs of old mobile phones, obtaining faster reaction kinetics by means of leaching with supercritical CO2 and co-solvents. The PCBs from waste mobile phones were characterized, and evaluation was made of the reaction kinetics during leaching at atmospheric pressure and using supercritical CO2 with H2O2 and H2SO4 as co-solvents. The results showed that the PCBs contained 34.83 wt% of Cu. It was found that the supercritical extraction was 9 times faster, compared to atmospheric pressure extraction. After 20 min of supercritical leaching, approximately 90% of the Cu contained in the PCB was extracted using a 1:20 solid:liquid ratio and 20% of H2O2 and H2SO4 (2.5 M). These results demonstrate the efficiency of the process. Therefore the supercritical CO2 employment in the PCBs recycling is a promising alternative and the CO2 is environmentally acceptable and reusable. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ultra-trace level analysis of morpholine, cyclohexylamine, and diethylaminoethanol in steam condensate by gas chromatography with multi-mode inlet, and flame ionization detection.

PubMed

Luong, J; Shellie, R A; Cortes, H; Gras, R; Hayward, T

2012-03-16

Steam condensate water treatment is a vital and integral part of the overall cooling water treatment process. Steam condensate often contains varying levels of carbon dioxide and oxygen which acts as an oxidizer. Carbon dioxide forms corrosive carbonic acid when dissolved in condensed steam. To neutralize the harmful effect of the carbonic acid, volatile amine compounds such as morpholine, cyclohexylamine, and diethylaminoethanol are often employed as part of a strategy to control corrosion in the water treatment process. Due to the high stability of these compounds in a water matrix, the indirect addition of such chemicals into the process via steam condensate often results in their presence throughout the process and even into the final product. It is therefore important to understand the impact of these chemicals and their fate within a chemical plant. The ability to analyze such compounds by gas chromatography has historically been difficult due to the lack of chromatographic system inertness at the trace level concentrations especially in an aqueous matrix. Here a highly sensitive, practical, and reliable gas chromatographic approach is described for the determination of morpholine, cyclohexylamine, and diethylaminoethanol in steam condensate at the part-per-billion (ppb) levels. The approach does not require any sample enrichment or derivatization. The technique employs a multi-mode inlet operating in pulsed splitless mode with programmed inlet temperature for sample introduction, an inert base-deactivated capillary column for solute separation and flame ionization detection. Chromatographic performance was further enhanced by the incorporation of 2-propanol as a co-solvent. Detection limits for morpholine, cyclohexylamine, diethylaminoethanol were established to be 100 ppb (v/v), with relative standard deviations (RSD) of less than 6% at the 95% confidence level (n=20) and a percent recovery of 96% or higher for the solutes of interest over a range of 0

Impregnation of Fenofibrate on mesoporous silica using supercritical carbon dioxide.

PubMed

Bouledjouidja, Abir; Masmoudi, Yasmine; Van Speybroeck, Michiel; Schueller, Laurent; Badens, Elisabeth

2016-02-29

Low oral bioavailability can be circumvented by the formulation of the poorly water soluble drug in ordered mesoporous silica (OMS-L-7). Fenofibrate is an orally administered, poorly water-soluble active pharmaceutical ingredient (API), used clinically to lower lipid levels. Fenofibrate was loaded into silica using two methods: incipient wetness and supercritical impregnation. This study investigates the impact of loading and the impact of varying supercritical carbon dioxide (scCO2) processing conditions. The objective is to enhance Fenofibrate loading into silica while reducing degree of the drug crystallinity, so as to increase the drug's dissolution rate and its bioavailability. The comparison of both impregnation processes was made in terms of impregnation yields and duration as well as physical characterization of the drug. While incipient wetness method led to a Fenofibrate loading up to 300 mgdrug/gsilica in 48 h of impregnation, the supercritical impregnation method yielded loading up to 485 mgdrug/gsilica in 120 min of impregnation duration, at 16 MPa and 308 K, with a low degree of crystallinity (about 1%) comparable to the crystallinity observed via the solvent method. In addition to the enhancement of impregnation efficiency, the supercritical route provides a solvent-free alternative for impregnation. Copyright © 2015 Elsevier B.V. All rights reserved.

Vapor generator steam drum spray head

DOEpatents

Fasnacht, Jr., Floyd A.

1978-07-18

A typical embodiment of the invention provides a combination feedwater and "cooldown" water spray head that is centrally disposed in the lower portion of a nuclear power plant steam drum. This structure not only discharges the feedwater in the hottest part of the steam drum, but also increases the time required for the feedwater to reach the steam drum shell, thereby further increasing the feedwater temperature before it contacts the shell surface, thus reducing thermal shock to the steam drum structure.

Process for treating effluent from a supercritical water oxidation reactor

DOEpatents

Barnes, Charles M.; Shapiro, Carolyn

1997-01-01

A method for treating a gaseous effluent from a supercritical water oxidation reactor containing entrained solids is provided comprising the steps of expanding the gas/solids effluent from a first to a second lower pressure at a temperature at which no liquid condenses; separating the solids from the gas effluent; neutralizing the effluent to remove any acid gases; condensing the effluent; and retaining the purified effluent to the supercritical water oxidation reactor.

Process for treating effluent from a supercritical water oxidation reactor

DOEpatents

Barnes, C.M.; Shapiro, C.

1997-11-25

A method for treating a gaseous effluent from a supercritical water oxidation reactor containing entrained solids is provided comprising the steps of expanding the gas/solids effluent from a first to a second lower pressure at a temperature at which no liquid condenses; separating the solids from the gas effluent; neutralizing the effluent to remove any acid gases; condensing the effluent; and retaining the purified effluent to the supercritical water oxidation reactor. 6 figs.

Methods for producing films using supercritical fluid

DOEpatents

Yonker, Clement R.; Fulton, John L.

2004-06-15

A method for forming a continuous film on a substrate surface that involves depositing particles onto a substrate surface and contacting the particle-deposited substrate surface with a supercritical fluid under conditions sufficient for forming a continuous film from the deposited particles. The particles may have a mean particle size of less 1 micron. The method may be performed by providing a pressure vessel that can contain a compressible fluid. A particle-deposited substrate is provided in the pressure vessel and the compressible fluid is maintained at a supercritical or sub-critical state sufficient for forming a film from the deposited particles. The T.sub.g of particles may be reduced by subjecting the particles to the methods detailed in the present disclosure.

Enzyme microheterogeneous hydration and stabilization in supercritical carbon dioxide.

PubMed

Silveira, Rodrigo L; Martínez, Julian; Skaf, Munir S; Martínez, Leandro

2012-05-17

Supercritical carbon dioxide is a promising green-chemistry solvent for many enzyme-catalyzed chemical reactions, yet the striking stability of some enzymes in such unconventional environments is not well understood. Here, we investigate the stabilization of the Candida antarctica Lipase B (CALB) in supercritical carbon dioxide-water biphasic systems using molecular dynamics simulations. The preservation of the enzyme structure and optimal activity depend on the presence of small amounts of water in the supercritical dispersing medium. When the protein is at least partially hydrated, water molecules bind to specific sites on the enzyme surface and prevent carbon dioxide from penetrating its catalytic core. Strikingly, water and supercritical carbon dioxide cover the protein surface quite heterogeneously. In the first solvation layer, the hydrophilic residues at the surface of the protein are able to pin down patches of water, whereas carbon dioxide solvates preferentially hydrophobic surface residues. In the outer solvation shells, water molecules tend to cluster predominantly on top of the larger water patches of the first solvation layer instead of spreading evenly around the remainder of the protein surface. For CALB, this exposes the substrate-binding region of the enzyme to carbon dioxide, possibly facilitating diffusion of nonpolar substrates into the catalytic funnel. Therefore, by means of microheterogeneous solvation, enhanced accessibility of hydrophobic substrates to the active site can be achieved, while preserving the functional structure of the enzyme. Our results provide a molecular picture on the nature of the stability of proteins in nonaqueous media.

Steampunk: Full Steam Ahead

ERIC Educational Resources Information Center

Campbell, Heather M.

2010-01-01

Steam-powered machines, anachronistic technology, clockwork automatons, gas-filled airships, tentacled monsters, fob watches, and top hats--these are all elements of steampunk. Steampunk is both speculative fiction that imagines technology evolved from steam-powered cogs and gears--instead of from electricity and computers--and a movement that…

The latent heat of vaporization of supercritical fluids

NASA Astrophysics Data System (ADS)

Banuti, Daniel; Raju, Muralikrishna; Hickey, Jean-Pierre; Ihme, Matthias

2016-11-01

The enthalpy of vaporization is the energy required to overcome intermolecular attractive forces and to expand the fluid volume against the ambient pressure when transforming a liquid into a gas. It diminishes for rising pressure until it vanishes at the critical point. Counterintuitively, we show that a latent heat is in fact also required to heat a supercritical fluid from a liquid to a gaseous state. Unlike its subcritical counterpart, the supercritical pseudoboiling transition is spread over a finite temperature range. Thus, in addition to overcoming intermolecular attractive forces, added energy simultaneously heats the fluid. Then, considering a transition from a liquid to an ideal gas state, we demonstrate that the required enthalpy is invariant to changes in pressure for 0 < p < 3pcr . This means that the classical pressure-dependent latent heat is merely the equilibrium part of the phase transition. The reduction at higher pressures is compensated by an increase in a nonequilibrium latent heat required to overcome residual intermolecular forces in the real fluid vapor during heating. At supercritical pressures, all of the transition occurs at non-equilibrium; for p -> 0 , all of the transition occurs at equilibrium.

7 CFR 29.3058 - Steam-dried.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Steam-dried. 29.3058 Section 29.3058 Agriculture... Steam-dried. The condition of unfermented tobacco as customarily prepared for storage by means of a redrying machine or other steam-conditioning equipment. [24 FR 8771, Oct. 29, 1959. Redesignated at 47 FR...

Supercritical/Solid Catalyst (SSC)

ScienceCinema

Ginosar, Daniel; Fox, Robert; Bright, Patricia

2018-05-23

INL's patented, continuous-flow Supercritical/Solid Catalyst (SSC) produces the highest ASTM-quality B-100 biodiesel from waste fats, oils, and greases at the site of waste generation. SSC delivers low-cost transportation fuel, avoids significant landfill costs for municipalities, and reduces potent methane and other emissions produced in landfills from these wastes. You can learn more about INL's energy research programs at http://www.facebook.com/idahonationallaboratory.

Supercritical/Solid Catalyst (SSC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ginosar, Daniel; Fox, Robert; Bright, Patricia

2010-05-28

INL's patented, continuous-flow Supercritical/Solid Catalyst (SSC) produces the highest ASTM-quality B-100 biodiesel from waste fats, oils, and greases at the site of waste generation. SSC delivers low-cost transportation fuel, avoids significant landfill costs for municipalities, and reduces potent methane and other emissions produced in landfills from these wastes. You can learn more about INL's energy research programs at http://www.facebook.com/idahonationallaboratory.

Model-free adaptive control of advanced power plants

DOEpatents

Cheng, George Shu-Xing; Mulkey, Steven L.; Wang, Qiang

2015-08-18

A novel 3-Input-3-Output (3.times.3) Model-Free Adaptive (MFA) controller with a set of artificial neural networks as part of the controller is introduced. A 3.times.3 MFA control system using the inventive 3.times.3 MFA controller is described to control key process variables including Power, Steam Throttle Pressure, and Steam Temperature of boiler-turbine-generator (BTG) units in conventional and advanced power plants. Those advanced power plants may comprise Once-Through Supercritical (OTSC) Boilers, Circulating Fluidized-Bed (CFB) Boilers, and Once-Through Supercritical Circulating Fluidized-Bed (OTSC CFB) Boilers.

High-Pressure Liquid Chromatograph with Mass Spectrometric Detection for Analysis of Supercritical Fuels Pyrolysis Products

DTIC Science & Technology

2006-08-01

conditions will necessarily be supercritical fluids . These temperatures and pressures will also cause the fuel to undergo pyrolytic reactions, which...Spectrometric Detection for 5a. CONTRACT NUMBER Analysis of Supercritical Fuels Pyrolysis Products 5b. GRANT NUMBER FA9550-05-1-0253 5c... supercritical pyrolysis experiments with the model fuels 1-methylnaphthalene and toluene. The HPLC/UV/MS instrument facilitated the identification of fifteen 5

Supercritical Fluid Extraction of Bacterial and Archaeal Lipid Biomarkers from Anaerobically Digested Sludge

PubMed Central

Hanif, Muhammad; Atsuta, Yoichi; Fujie, Koichi; Daimon, Hiroyuki

2012-01-01

Supercritical fluid extraction (SFE) was used in the analysis of bacterial respiratory quinone (RQ), bacterial phospholipid fatty acid (PLFA), and archaeal phospholipid ether lipid (PLEL) from anaerobically digested sludge. Bacterial RQ were determined using ultra performance liquid chromatography (UPLC). Determination of bacterial PLFA and archaeal PLEL was simultaneously performed using gas chromatography-mass spectrometry (GC-MS). The effects of pressure, temperature, and modifier concentration on the total amounts of RQ, PLFA, and PLEL were investigated by 23 experiments with five settings chosen for each variable. The optimal extraction conditions that were obtained through a multiple-response optimization included a pressure of 23.6 MPa, temperature of 77.6 °C, and 10.6% (v/v) of methanol as the modifier. Thirty nine components of microbial lipid biomarkers were identified in the anaerobically digested sludge. Overall, the SFE method proved to be more effective, rapid, and quantitative for simultaneously extracting bacterial and archaeal lipid biomarkers, compared to conventional organic solvent extraction. This work shows the potential application of SFE as a routine method for the comprehensive analysis of microbial community structures in environmental assessments using the lipid biomarkers profile. PMID:22489140

[Research of the essential oil of Plumeria rubra var. actifolia from Laos by supercritical carbon dioxide extraction].

PubMed

Xiao, Xin-Yu; Cui, Long-Hai; Zhou, Xin-Xin; Wu, Yan; Ge, Fa-Huan

2011-05-01

The orthogonal test and the supercritical carbon dioxide fluid extraction were used for optimizing the extraction of the essential oil from Plumeria rubra var. actifolia for the first time. Compared with the steam distillation, the optimal operation parameter of extraction was as follows: extraction pressure 25 MPa, extraction temperature 45 degrees C; separator I pressure 12 MPa, separator I temperature 55 degrees C; separator II pressure 6 MPa, separator II temperature 30 degrees C. Under this condition the yield of the essential oil was 5.8927%. The components were separated and identified by GC-MS. 53 components of Plumeria rubra var. actifolia measured by SFE method were identified and determined by normalization method. The main components were 1, 6, 10-dodecatrien-3-ol, 3, 7, 11-trimethyl, benzoic acid, 2-hydroxy-, phenylmethyl ester, 1, 2-benzenedicarboxylic acid, bis(2-methylpropyl) ester,etc.. 1, 2-Benzenedicarboxylic acid, bis (2-methylpropyl) este. took up 66.11% of the total amount, and there was much difference of the results from SD method.

Supercritical-Multiple-Solvent Extraction From Coal

NASA Technical Reports Server (NTRS)

Corcoran, W.; Fong, W.; Pichaichanarong, P.; Chan, P.; Lawson, D.

1983-01-01

Large and small molecules dissolve different constituents. Experimental apparatus used to test supercritical extraction of hydrogen rich compounds from coal in various organic solvents. In decreasing order of importance, relevant process parameters were found to be temperature, solvent type, pressure, and residence time.

Two-structured solid particle model for predicting and analyzing supercritical extraction performance.

PubMed

Samadi, Sara; Vaziri, Behrooz Mahmoodzadeh

2017-07-14

Solid extraction process, using the supercritical fluid, is a modern science and technology, which has come in vogue regarding its considerable advantages. In the present article, a new and comprehensive model is presented for predicting the performance and separation yield of the supercritical extraction process. The base of process modeling is partial differential mass balances. In the proposed model, the solid particles are considered twofold: (a) particles with intact structure, (b) particles with destructed structure. A distinct mass transfer coefficient has been used for extraction of each part of solid particles to express different extraction regimes and to evaluate the process accurately (internal mass transfer coefficient was used for the intact-structure particles and external mass transfer coefficient was employed for the destructed-structure particles). In order to evaluate and validate the proposed model, the obtained results from simulations were compared with two series of available experimental data for extraction of chamomile extract with supercritical carbon dioxide, which had an excellent agreement. This is indicative of high potentiality of the model in predicting the extraction process, precisely. In the following, the effect of major parameters on supercritical extraction process, like pressure, temperature, supercritical fluid flow rate, and the size of solid particles was evaluated. The model can be used as a superb starting point for scientific and experimental applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Running Out of Steam.

ERIC Educational Resources Information Center

Kumar, Promod

2000-01-01

Explains why schools should evaluate whether their older steam-heating systems are still cost-effective, or need to be repaired or replaced. The symptoms of deterioration are listed along with discussions on repair or replacement decision making on three areas of steam heating systems: boilers; distribution system; and terminal equipment. (GR)

Diffusion coefficients of phenylbutazone in supercritical CO2 and in ethanol.

PubMed

Kong, Chang Yi; Watanabe, Kou; Funazukuri, Toshitaka

2013-03-01

The diffusion coefficients D(12) of phenylbutazone at infinite dilution in supercritical CO(2) were measured by the chromatographic impulse response (CIR) method. The measurements were carried out over the temperature range from 308.2 to 343.2 K at pressures up to 40.0 MPa. In addition, the D(12) data of phenylbutazone at infinite dilution in ethanol were also measured by the Taylor dispersion method at 298.2-333.2K and at atmospheric pressure. The D(12) value of phenylbutazone increased from 4.45×10(-10) m(2) s(-1) at 298.2 K and 0.1 MPa in ethanol to about 1.43×10(-8) m(2) s(-1) at 343.2 K and 14.0 MPa in supercritical CO(2). It was found that all diffusion data of phenylbutazone measured in this study in supercritical CO(2) and in ethanol can be satisfactorily represented by the hydrodynamic equation over a wide range of fluid viscosity from supercritical state to liquid state with average absolute relative deviation of 5.4% for 112 data points. Copyright © 2013 Elsevier B.V. All rights reserved.

Supercritical waste oxidation of aqueous wastes

NASA Technical Reports Server (NTRS)

Modell, M.

1986-01-01

For aqueous wastes containing 1 to 20 wt% organics, supercritical water oxidation is less costly than controlled incineration or activated carbon treatment and far more efficient than wet oxidation. Above the critical temperature (374 C) and pressure (218 atm) of water, organic materials and gases are completely miscible with water. In supercritical water oxidation, organics, air and water are brought together in a mixture at 250 atm and temperatures above 400 C. Organic oxidation is initiated spontaneously at these conditions. The heat of combustion is released within the fluid and results in a rise in temperature 600 to 650 C. Under these conditions, organics are destroyed rapidly with efficiencies in excess of 99.999%. Heteroatoms are oxidized to acids, which can be precipitated out as salts by adding a base to the feed. Examples are given for process configurations to treat aqueous wastes with 10 and 2 wt% organics.

A general strategy for the ultrafast surface modification of metals.

PubMed

Shen, Mingli; Zhu, Shenglong; Wang, Fuhui

2016-12-07

Surface modification is an essential step in engineering materials that can withstand the increasingly aggressive environments encountered in various modern energy-conversion systems and chemical processing industries. However, most traditional technologies exhibit disadvantages such as slow diffusion kinetics, processing difficulties or compatibility issues. Here, we present a general strategy for the ultrafast surface modification of metals inspired by electromigration, using aluminizing austenitic stainless steel as an example. Our strategy facilitates the rapid formation of a favourable ductile surface layer composed of FeCrAl or β-FeAl within only 10 min compared with several hours in conventional processes. This result indicates that electromigration can be used to achieve the ultrafast surface modification of metals and can overcome the limitations of traditional technologies. This strategy could be used to aluminize ultra-supercritical steam tubing to withstand aggressive oxidizing environments.

A general strategy for the ultrafast surface modification of metals

PubMed Central

Shen, Mingli; Zhu, Shenglong; Wang, Fuhui

2016-01-01

Surface modification is an essential step in engineering materials that can withstand the increasingly aggressive environments encountered in various modern energy-conversion systems and chemical processing industries. However, most traditional technologies exhibit disadvantages such as slow diffusion kinetics, processing difficulties or compatibility issues. Here, we present a general strategy for the ultrafast surface modification of metals inspired by electromigration, using aluminizing austenitic stainless steel as an example. Our strategy facilitates the rapid formation of a favourable ductile surface layer composed of FeCrAl or β-FeAl within only 10 min compared with several hours in conventional processes. This result indicates that electromigration can be used to achieve the ultrafast surface modification of metals and can overcome the limitations of traditional technologies. This strategy could be used to aluminize ultra-supercritical steam tubing to withstand aggressive oxidizing environments. PMID:27924909

7 CFR 29.3548 - Steam-dried.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Steam-dried. 29.3548 Section 29.3548 Agriculture... Type 95) § 29.3548 Steam-dried. The condition of unfermented tobacco as customarily prepared for storage by means of a redrying machine or other steam-conditioning equipment. [30 FR 9207, July 23, 1965...

7 CFR 29.1060 - Steam-dried.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Steam-dried. 29.1060 Section 29.1060 Agriculture... Type 92) § 29.1060 Steam-dried. The condition of unfermented tobacco as customarily prepared for storage by means of a redrying machine or other steam-conditioning equipment. [42 FR 21092, Apr. 25, 1977...

7 CFR 29.2300 - Steam-dried.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Steam-dried. 29.2300 Section 29.2300 Agriculture... INSPECTION Standards Official Standard Grades for Virginia Fire-Cured Tobacco (u.s. Type 21) § 29.2300 Steam... machine or other steam-conditioning equipment. [37 FR 13521, July 11, 1972. Redesignated at 51 FR 40406...

7 CFR 29.2552 - Steam-dried.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Steam-dried. 29.2552 Section 29.2552 Agriculture...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2552 Steam-dried. The condition of unfermented tobacco as customarily prepared for storage by means of a redrying machine or other steam...

Welding Metallurgy of Nickel-Based Superalloys for Power Plant Construction

NASA Astrophysics Data System (ADS)

Tung, David C.

Increasing the steam temperature and pressure in coal-fired power plants is a perpetual goal driven by the pursuit of increasing thermal cycle efficiency and reducing fuel consumption and emissions. The next target steam operating conditions, which are 760°C (1400°F) and 35 MPa (5000 psi) are known as Advanced Ultra Supercritical (AUSC), and can reduce CO2 emissions up to 13% but this cannot be achieved with traditional power plant construction materials. The use of precipitation-strengthened Nickel-based alloys (superalloys) is required for components which will experience the highest operating temperatures. The leading candidate superalloys for power plant construction are alloys 740H, 282, and 617. Superalloys have excellent elevated temperature properties due to careful microstructural design which is achieved through very specific heat treatments, often requiring solution annealing or homogenization at temperatures of 1100 °C or higher. A series of postweld heat treatments was investigated and it was found that homogenization steps before aging had no noticeable effect on weld metal microhardness, however; there were clear improvements in weld metal homogeneity. The full abstract can be viewed in the document itself.

Supercritical multicomponent solvent coal extraction

NASA Technical Reports Server (NTRS)

Corcoran, W. H.; Fong, W. S.; Pichaichanarong, P.; Chan, P. C. F.; Lawson, D. D. (Inventor)

1983-01-01

The yield of organic extract from the supercritical extraction of coal with larger diameter organic solvents such as toluene is increased by use of a minor amount of from 0.1 to 10% by weight of a second solvent such as methanol having a molecular diameter significantly smaller than the average pore diameter of the coal.

Cleaning With Supercritical CO2

NASA Technical Reports Server (NTRS)

Herzstock, James J.

1990-01-01

Supercritical carbon dioxide effective industrial cleaning agent. Replaces conventional halocarbon solvents for degreasing parts becoming coated with oil during such manufacturing procedures as forming and machining. Presents none of environmental threats and occupational hazards associated with halocarbon solvents. Spontaneously evaporates after use and leaves no waste to be disposed of. Evaporated gas readily collected and recycled.

Process for purifying geothermal steam

DOEpatents

Li, Charles T.

1980-01-01

Steam containing hydrogen sulfide is purified and sulfur recovered by passing the steam through a reactor packed with activated carbon in the presence of a stoichiometric amount of oxygen which oxidizes the hydrogen sulfide to elemental sulfur which is adsorbed on the bed. The carbon can be recycled after the sulfur has been recovered by vacuum distillation, inert gas entrainment or solvent extraction. The process is suitable for the purification of steam from geothermal sources which may also contain other noncondensable gases.

Process for purifying geothermal steam

DOEpatents

Li, C.T.

Steam containing hydrogen sulfide is purified and sulfur recovered by passing the steam through a reactor packed with activated carbon in the presence of a stoichiometric amount of oxygen which oxidizes the hydrogen sulfide to elemental sulfur which is adsorbed on the bed. The carbon can be recycled after the sulfur has been recovered by vacuum distillation, inert gas entrainment or solvent extraction. The process is suitable for the purification of steam from geothermal sources which may also contain other noncondensable gases.

Dynamics, thermodynamics and structure of liquids and supercritical fluids: crossover at the Frenkel line

NASA Astrophysics Data System (ADS)

Fomin, Yu D.; Ryzhov, V. N.; Tsiok, E. N.; Proctor, J. E.; Prescher, C.; Prakapenka, V. B.; Trachenko, K.; Brazhkin, V. V.

2018-04-01

We review recent work aimed at understanding dynamical and thermodynamic properties of liquids and supercritical fluids. The focus of our discussion is on solid-like transverse collective modes, whose evolution in the supercritical fluids enables one to discuss the main properties of the Frenkel line separating rigid liquid-like and non-rigid gas-like supercritical states. We subsequently present recent experimental evidence of the Frenkel line showing that structural and dynamical crossovers are seen at a pressure and temperature corresponding to the line as predicted by theory and modelling. Finally, we link dynamical and thermodynamic properties of liquids and supercritical fluids by the new calculation of liquid energy governed by the evolution of solid-like transverse modes. The disappearance of those modes at high temperature results in the observed decrease of heat capacity.

[Optimization for supercritical CO2 extraction with response surface methodology of Prunus armeniaca oil].

PubMed

Chen, Fei-Fei; Wu, Yan; Ge, Fa-Huan

2012-03-01

To optimize the extraction conditions of Prunus armeniaca oil by Supercritical CO2 extraction and identify its components by GC-MS. Optimized of SFE-CO extraction by response surface methodology and used GC-MS to analysis Prunus armeniaca oil compounds. Established the model of an equation for the extraction rate of Prunus armeniaca oil by supercritical CO2 extraction, and the optimal parameters for the supercritical CO2 extraction determined by the equation were: the extraction pressure was 27 MPa, temperature was 39 degrees C, the extraction rate of Prunus armeniaca oil was 44.5%. 16 main compounds of Prunus armeniaca oil extracted by supercritical CO2 were identified by GC-MS, unsaturated fatty acids were 92.6%. This process is simple, and can be used for the extraction of Prunus armeniaca oil.

Supercritical Carbon Dioxide Extraction of Selected Herbal Leaves: An Overview

NASA Astrophysics Data System (ADS)

Hamid, I. A. Abd; Ismail, N.; Rahman, N. Abd

2018-05-01

Supercritical fluid extraction of carbon dioxide (SC-CO2) is one of new alternative extraction method that has been widely used to isolate bioactive components from variety of plant materials. The method was proved to be clean and safe, compatible for the extraction of edible products such as spices, food additives, medicines and nutritional supplement products compared to traditional extraction techniques such as solvent extraction, hydro distillation and steam distillation. The SC-CO2 extraction was known as highly influenced by its process parameter such as temperature and pressure for obtaining maximum yield. Therefore, a clear review on the optimum range of temperature and pressure for herbal leaves extraction using SC-CO2 is necessary for future reference. The aim of this work is to analyze the effect of temperature and pressure of SC-CO2 process without modifier on extraction yield of some selected herbal leaves i.e clubmoss, drumstick leaves, kratom leaves, mallee and myrtle leaves. The values of investigated parameters were; pressure from 8.9 to 50 MPa and temperature from 35 to 80°C. The results showed that the highest extraction yields were obtained when the pressure and temperature were above 30 MPa and 40°C. The interaction between pressure and temperature for SC-CO2 extraction of plant leaves are crucial since the values cannot be very high or very low in order to preserve the quality of the extracts.

Supercritical Fluid Extraction of Pyrrolidine Alkaloid from Leaves of Piper amalago L.

PubMed Central

Filho, L. C.; Faiões, V. S.; Cunha-Júnior, E. F.; Torres-Santos, E. C.; Cortez, D. A. G.

2017-01-01

Supercritical fluid extraction was used to extract the alkaloid N-[7-(3′,4′-methylenedioxyphenyl)-2(Z),4(Z)-heptadienoyl]pyrrolidine from leaves of Piper amalago L. A three-level orthogonal array design matrix, OAD OA9(34), was used for optimization of the parameters of supercritical extraction of the alkaloid, employing supercritical carbon dioxide: extraction time (20, 40, and 60 min), temperature (40, 50, and 60°C), pressure (150, 200, and 250 bar), and the use of cosolvents (ethanol, methanol, and propyleneglycol). All parameters had significant effect on the alkaloid yield. The alkaloid yield after 60 min of extraction without cosolvents at 9 different conditions (32) in terms of temperature (40, 50, and 60°C) and pressure (150, 200, and 250 bar) was also evaluated. The optimal yield (≈3.8 mg g−1) was obtained with supercritical CO2 + methanol (5% v : v) at 40°C and 200 bar for 60 min of extraction. PMID:28539966

Extraction of aucubin from seeds of Eucommia ulmoides Oliv. using supercritical carbon dioxide.

PubMed

Li, Hui; Hu, Jiangyu; Ouyang, Hui; Li, Yanan; Shi, Hui; Ma, Chengjin; Zhang, Yongkang

2009-01-01

Supercritical CO2 was used as solvent for the extraction of aucubin from the seeds of Eucommia ulmoides Oliv. The co-solvent composition was tested and extraction conditions were optimized. Results showed that the best co-solvent was a water-ethanol mixture (1 + 3, v/v), and the highest yield was obtained when the extraction was performed under 26 MPa at extraction and separation temperatures of 55 and 30 degrees C for 120 min, using 6 mL co-solvent/g material at a CO2 flow rate of 20 L/h. In a comparison of the supercritical CO2 and Soxhlet extraction methods, the Soxhlet method needed 3 h to extract 10 g material, whereas the supercritical CO2 extraction technique needed only 2 h to extract 100 g material, thus showing a high extraction capability. The supercritical CO2 extraction produced a higher yield, with a lower cost for the extraction. Owing to the advantages of low extraction temperature, high yield, and ease of separating the product from the solvent, supercritical CO2 extraction is likely to be developed into an ideal technique for the extraction of aucubin, a compound with thermal instability, from the seeds of this plant.

Supercritical separation process for complex organic mixtures

DOEpatents

Chum, Helena L.; Filardo, Giuseppe

1990-01-01

A process is disclosed for separating low molecular weight components from complex aqueous organic mixtures. The process includes preparing a separation solution of supercritical carbon dioxide with an effective amount of an entrainer to modify the solvation power of the supercritical carbon dioxide and extract preselected low molecular weight components. The separation solution is maintained at a temperature of at least about 70.degree. C. and a pressure of at least about 1,500 psi. The separation solution is then contacted with the organic mixtures while maintaining the temperature and pressure as above until the mixtures and solution reach equilibrium to extract the preselected low molecular weight components from the organic mixtures. Finally, the entrainer/extracted components portion of the equilibrium mixture is isolated from the separation solution.

Supercritical separation process for complex organic mixtures

DOEpatents

Chum, H.L.; Filardo, G.

1990-10-23

A process is disclosed for separating low molecular weight components from complex aqueous organic mixtures. The process includes preparing a separation solution of supercritical carbon dioxide with an effective amount of an entrainer to modify the solvation power of the supercritical carbon dioxide and extract preselected low molecular weight components. The separation solution is maintained at a temperature of at least about 70 C and a pressure of at least about 1,500 psi. The separation solution is then contacted with the organic mixtures while maintaining the temperature and pressure as above until the mixtures and solution reach equilibrium to extract the preselected low molecular weight components from the organic mixtures. Finally, the entrainer/extracted components portion of the equilibrium mixture is isolated from the separation solution. 1 fig.

Experimental research of heterogeneous nuclei in superheated steam

NASA Astrophysics Data System (ADS)

Bartoš, Ondřej; Kolovratník, Michal; Šmíd, Bohuslav; Hrubý, Jan

2016-03-01

A mobile steam expansion chamber has been developed to investigate experimentally homogeneous and heterogeneous nucleation processes in steam, both in the laboratory and at power plants using the steam withdrawn from the steam turbine. The purpose of the device is to provide new insight into the physics of nonequilibrium wet steam formation, which is one of the factors limiting the efficiency and reliability of steam turbines. The expanded steam or a mixture of steam with a non-condensable gas rapidly expands in the expansion chamber. Due to adiabatic cooling, the temperature drops below the dew point of the steam at a given pressure. When reaching a sufficiently high supersaturation, droplets are nucleated. By tuning the supersaturation in the so-called nucleation pulse, particles of various size ranges can be activated. This fact is used in the present study to measure the aerosol particles present in the air. Homogeneous nucleation was negligible in this case. The experiment demonstrates the functionality of the device, data acquisition system and data evaluation methods.

Supercritical solvent coal extraction

NASA Technical Reports Server (NTRS)

Compton, L. E. (Inventor)

1984-01-01

Yields of soluble organic extract are increased up to about 50% by the supercritical extraction of particulate coal at a temperature below the polymerization temperature for coal extract fragments (450 C.) and a pressure from 500 psig to 5,000 psig by the conjoint use of a solvent mixture containing a low volatility, high critical temperature coal dissolution catalyst such as phenanthrene and a high volatility, low critical temperature solvent such as toluene.

Thermochemically recuperated and steam cooled gas turbine system

DOEpatents

Viscovich, Paul W.; Bannister, Ronald L.

1995-01-01

A gas turbine system in which the expanded gas from the turbine section is used to generate the steam in a heat recovery steam generator and to heat a mixture of gaseous hydrocarbon fuel and the steam in a reformer. The reformer converts the hydrocarbon gas to hydrogen and carbon monoxide for combustion in a combustor. A portion of the steam from the heat recovery steam generator is used to cool components, such as the stationary vanes, in the turbine section, thereby superheating the steam. The superheated steam is mixed into the hydrocarbon gas upstream of the reformer, thereby eliminating the need to raise the temperature of the expanded gas discharged from the turbine section in order to achieve effective conversion of the hydrocarbon gas.

49 CFR 230.21 - Steam locomotive number change.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotive number change. 230.21 Section 230... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General Recordkeeping Requirements § 230.21 Steam locomotive number change. When a steam locomotive number is changed...

Exp6-polar thermodynamics of dense supercritical water

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bastea, S; Fried, L E

2007-12-13

We introduce a simple polar fluid model for the thermodynamics of dense supercritical water based on a Buckingham (exp-6) core and point dipole representation of the water molecule. The proposed exp6-polar thermodynamics, based on ideas originally applied to dipolar hard spheres, performs very well when tested against molecular dynamics simulations. Comparisons of the model predictions with experimental data available for supercritical water yield excellent agreement for the shock Hugoniot, isotherms and sound speeds, and are also quite good for the self-diffusion constant and relative dielectric constant. We expect the present approach to be also useful for other small polar moleculesmore » and their mixtures.« less

Optical steam quality measurement system and method

DOEpatents

Davidson, James R.; Partin, Judy K.

2006-04-25

An optical measurement system is presented that offers precision on-line monitoring of the quality of steam. Multiple wavelengths of radiant energy are passed through the steam from an emitter to a detector. By comparing the amount of radiant energy absorbed by the flow of steam for each wavelength, a highly accurate measurement of the steam quality can be determined on a continuous basis in real-time. In an embodiment of the present invention, the emitter, comprises three separate radiant energy sources for transmitting specific wavelengths of radiant energy through the steam. In a further embodiment, the wavelengths of radiant energy are combined into a single beam of radiant energy for transmission through the steam using time or wavelength division multiplexing. In yet a further embodiment, the single beam of radiant energy is transmitted using specialized optical elements.

A biocompatible tissue scaffold produced by supercritical fluid processing for cartilage tissue engineering.

PubMed

Kim, Su Hee; Jung, Youngmee; Kim, Soo Hyun

2013-03-01

Supercritical fluids are used in various industrial fields, such as the food and medical industries, because they have beneficial physical and chemical properties and are also nonflammable and inexpensive. In particular, supercritical carbon dioxide (ScCO(2)) is attractive due to its mild critical temperature, pressure values, and nontoxicity. Poly(L-lactide-co-ɛ-caprolactone) (PLCL), which is a biocompatible, biodegradable, and very elastic polymer, has been used in cartilage tissue engineering. However, organic solvents, such as chloroform or dichloromethane, are usually used for the fabrication of a PLCL scaffold through conventional methods. This leads to a cytotoxic effect and long processing time for removing solvents. To alleviate these problems, supercritical fluid processing is introduced here. In this study, we fabricated a mechano-active PLCL scaffold by supercritical fluid processing for cartilage tissue engineering, and we compared it with a scaffold made by a conventional solvent-casting method in terms of physical and biological performance. Also, to examine the optimum condition for preparing scaffolds with ScCO(2), we investigated the effects of pressure, temperature, and the depressurization rate on PLCL foaming. The PLCL scaffolds produced by supercritical fluid processing had a homogeneously interconnected porous structure, and they exhibited a narrow pore size distribution. Also, there was no cytotoxicity of the scaffolds made with ScCO(2) compared to the scaffolds made by the solvent-pressing method. The scaffolds were seeded with chondrocytes, and they were subcutaneously implanted into nude mice for up to 4 weeks. In vivo accumulation of extracellular matrix of cell-scaffold constructs demonstrated that the PLCL scaffold made with ScCO(2) formed a mature and well-developed cartilaginous tissue compared to the PLCL scaffold formed by solvent pressing. Consequently, these results indicated that the PLCL scaffolds made by supercritical fluid

Geological Model of Supercritical Geothermal Reservoir on the Top of the Magma Chamber

NASA Astrophysics Data System (ADS)

Tsuchiya, N.

2017-12-01

We are conducting supercritical geothermal project, and deep drilling project named as "JBBP: Japan Beyond Brittle Project" The temperatures of geothermal fields operating in Japan range from 200 to 300 °C (average 250 °C), and the depths range from 1000 to 2000 m (average 1500 m). In conventional geothermal reservoirs, the mechanical behavior of the rocks is presumed to be brittle, and convection of the hydrothermal fluid through existing network is the main method of circulation in the reservoir. In order to minimize induced seismicity, a rock mass that is "beyond brittle" is one possible candidate, because the rock mechanics of "beyond brittle" material is one of plastic deformation rather than brittle failure. To understand the geological model of a supercritical geothermal reservoir, granite-porphyry system, which had been formed in subduction zone, was investigated as a natural analog of the supercritical geothermal energy system. Quartz veins, hydrothermal breccia veins, and glassy veins are observed in a granitic body. The glassy veins formed at 500-550 °C under lithostatic pressures, and then pressures dropped drastically. The solubility of silica also dropped, resulting in formation of quartz veins under a hydrostatic pressure regime. Connections between the lithostatic and hydrostatic pressure regimes were key to the formation of the hydrothermal breccia veins, and the granite-porphyry system provides useful information for creation of fracture clouds in supercritical geothermal reservoirs. A granite-porphyry system, associated with hydrothermal activity and mineralization, provides a suitable natural analog for studying a deep-seated geothermal reservoir where stockwork fracture systems are created in the presence of supercritical geothermal fluids. I describe fracture networks and their formation mechanisms using petrology and fluid inclusion studies in order to understand this "beyond brittle" supercritical geothermal reservoir, and a geological

Size-selective separation of polydisperse gold nanoparticles in supercritical ethane.

PubMed

Williams, Dylan P; Satherley, John

2009-04-09

The aim of this study was to use supercritical ethane to selectively disperse alkanethiol-stabilized gold nanoparticles of one size from a polydisperse sample in order to recover a monodisperse fraction of the nanoparticles. A disperse sample of metal nanoparticles with diameters in the range of 1-5 nm was prepared using established techniques then further purified by Soxhlet extraction. The purified sample was subjected to supercritical ethane at a temperature of 318 K in the pressure range 50-276 bar. Particles were characterized by UV-vis absorption spectroscopy, TEM, and MALDI-TOF mass spectroscopy. The results show that with increasing pressure the dispersibility of the nanoparticles increases, this effect is most pronounced for smaller nanoparticles. At the highest pressure investigated a sample of the particles was effectively stripped of all the smaller particles leaving a monodisperse sample. The relationship between dispersibility and supercritical fluid density for two different size samples of alkanethiol-stabilized gold nanoparticles was considered using the Chrastil chemical equilibrium model.

Processing of Materials for Regenerative Medicine Using Supercritical Fluid Technology.

PubMed

García-González, Carlos A; Concheiro, Angel; Alvarez-Lorenzo, Carmen

2015-07-15

The increase in the world demand of bone and cartilage replacement therapies urges the development of advanced synthetic scaffolds for regenerative purposes, not only providing mechanical support for tissue formation, but also promoting and guiding the tissue growth. Conventional manufacturing techniques have severe restrictions for designing these upgraded scaffolds, namely, regarding the use of organic solvents, shearing forces, and high operating temperatures. In this context, the use of supercritical fluid technology has emerged as an attractive solution to design solvent-free scaffolds and ingredients for scaffolds under mild processing conditions. The state-of-the-art on the technological endeavors for scaffold production using supercritical fluids is presented in this work with a critical review on the key processing parameters as well as the main advantages and limitations of each technique. A special stress is focused on the strategies suitable for the incorporation of bioactive agents (drugs, bioactive glasses, and growth factors) and the in vitro and in vivo performance of supercritical CO2-processed scaffolds.

Structural Evolution of Supercritical CO2 across the Frenkel Line.

PubMed

Bolmatov, Dima; Zav'yalov, D; Gao, M; Zhernenkov, Mikhail

2014-08-21

Here, we study structural properties of the supercritical carbon dioxide and discover the existence of persistent medium-range order correlations, which make supercritical carbon dioxide nonuniform and heterogeneous on an intermediate length scale. We report on the CO2 heterogeneity shell structure where, in the first shell, both carbon and oxygen atoms experience gas-like-type interactions with short-range order correlations while within the second shell, oxygen atoms essentially exhibit a liquid-like type of interactions due to localization of transverse-like phonon packets. Importantly, we highlight a catalytic role of atoms inside of the nearest-neighbor heterogeneity shell in providing a mechanism for diffusion and proving the existence of an additional thermodynamic boundary in the supercritical carbon dioxide on an intermediate length scale. Finally, we discuss important implications for answering the intriguing question whether Venus may have had CO2 oceans and urge for an experimental detection of this persistent local-order heterogeneity.

An investigation of supercritical-CO2 copper electroplating parameters for application in TSV chips

NASA Astrophysics Data System (ADS)

Chuang, Ho-Chiao; Lai, Wei-Hong; Sanchez, Jorge

2015-01-01

This study uses supercritical electroplating for the filling of through silicon vias (TSVs) in chips. The present study utilizes the inductively coupled plasma reactive ion etching (ICP RIE) process technique to etch the TSVs and discusses different supercritical-CO2 electroplating parameters, such as the supercritical pressure, the electroplating current density’s effect on the TSV Cu pillar filling time, the I-V curve, the electrical resistance and the hermeticity. In addition, the results for all the tests mentioned above have been compared to results from traditional electroplating techniques. For the testing, we will first discuss the hermeticity of the TSV Cu pillars, using a helium leaking test apparatus to assess the vacuum sealing of the fabricated TSV Cu pillars. In addition, this study also conducts tests for the electrical properties, which include the measurement of the electrical resistance of the TSV at both ends in the horizontal direction, followed by the passing of a high current (10 A, due to probe limitations) to check if the TSV can withstand it without burnout. Finally, the TSV is cut in half in cross-section to observe the filling of Cu pillars by the supercritical electroplating and check for voids. The important characteristic of this study is the use of the supercritical electroplating process without the addition of any surfactants to aid the filling of the TSVs, but by taking advantage of the high permeability and low surface tension of supercritical fluids to achieve our goal. The results of this investigation point to a supercritical pressure of 2000 psi and a current density of 3 A dm-2 giving off the best electroplating filling and hermeticity, while also being able to withstand a high current of 10 A, with a relatively short electroplating time of 3 h (when compared to our own traditional dc electroplating).

Thermodynamic analysis of steam-injected advanced gas turbine cycles

NASA Astrophysics Data System (ADS)

Pandey, Devendra; Bade, Mukund H.

2017-12-01

This paper deals with thermodynamic analysis of steam-injected gas turbine (STIGT) cycle. To analyse the thermodynamic performance of steam-injected gas turbine (STIGT) cycles, a methodology based on pinch analysis is proposed. This graphical methodology is a systematic approach proposed for a selection of gas turbine with steam injection. The developed graphs are useful for selection of steam-injected gas turbine (STIGT) for optimal operation of it and helps designer to take appropriate decision. The selection of steam-injected gas turbine (STIGT) cycle can be done either at minimum steam ratio (ratio of mass flow rate of steam to air) with maximum efficiency or at maximum steam ratio with maximum net work conditions based on the objective of plants designer. Operating the steam injection based advanced gas turbine plant at minimum steam ratio improves efficiency, resulting in reduction of pollution caused by the emission of flue gases. On the other hand, operating plant at maximum steam ratio can result in maximum work output and hence higher available power.

Separation of supercritical slab-fluids to form aqueous fluid and melt components in subduction zone magmatism.

PubMed

Kawamoto, Tatsuhiko; Kanzaki, Masami; Mibe, Kenji; Matsukage, Kyoko N; Ono, Shigeaki

2012-11-13

Subduction-zone magmatism is triggered by the addition of H(2)O-rich slab-derived components: aqueous fluid, hydrous partial melts, or supercritical fluids from the subducting slab. Geochemical analyses of island arc basalts suggest two slab-derived signatures of a melt and a fluid. These two liquids unite to a supercritical fluid under pressure and temperature conditions beyond a critical endpoint. We ascertain critical endpoints between aqueous fluids and sediment or high-Mg andesite (HMA) melts located, respectively, at 83-km and 92-km depths by using an in situ observation technique. These depths are within the mantle wedge underlying volcanic fronts, which are formed 90 to 200 km above subducting slabs. These data suggest that sediment-derived supercritical fluids, which are fed to the mantle wedge from the subducting slab, react with mantle peridotite to form HMA supercritical fluids. Such HMA supercritical fluids separate into aqueous fluids and HMA melts at 92 km depth during ascent. The aqueous fluids are fluxed into the asthenospheric mantle to form arc basalts, which are locally associated with HMAs in hot subduction zones. The separated HMA melts retain their composition in limited equilibrium with the surrounding mantle. Alternatively, they equilibrate with the surrounding mantle and change the major element chemistry to basaltic composition. However, trace element signatures of sediment-derived supercritical fluids remain more in the melt-derived magma than in the fluid-induced magma, which inherits only fluid-mobile elements from the sediment-derived supercritical fluids. Separation of slab-derived supercritical fluids into melts and aqueous fluids can elucidate the two slab-derived components observed in subduction zone magma chemistry.

Separation of supercritical slab-fluids to form aqueous fluid and melt components in subduction zone magmatism

PubMed Central

Kawamoto, Tatsuhiko; Kanzaki, Masami; Mibe, Kenji; Ono, Shigeaki

2012-01-01

Subduction-zone magmatism is triggered by the addition of H2O-rich slab-derived components: aqueous fluid, hydrous partial melts, or supercritical fluids from the subducting slab. Geochemical analyses of island arc basalts suggest two slab-derived signatures of a melt and a fluid. These two liquids unite to a supercritical fluid under pressure and temperature conditions beyond a critical endpoint. We ascertain critical endpoints between aqueous fluids and sediment or high-Mg andesite (HMA) melts located, respectively, at 83-km and 92-km depths by using an in situ observation technique. These depths are within the mantle wedge underlying volcanic fronts, which are formed 90 to 200 km above subducting slabs. These data suggest that sediment-derived supercritical fluids, which are fed to the mantle wedge from the subducting slab, react with mantle peridotite to form HMA supercritical fluids. Such HMA supercritical fluids separate into aqueous fluids and HMA melts at 92 km depth during ascent. The aqueous fluids are fluxed into the asthenospheric mantle to form arc basalts, which are locally associated with HMAs in hot subduction zones. The separated HMA melts retain their composition in limited equilibrium with the surrounding mantle. Alternatively, they equilibrate with the surrounding mantle and change the major element chemistry to basaltic composition. However, trace element signatures of sediment-derived supercritical fluids remain more in the melt-derived magma than in the fluid-induced magma, which inherits only fluid-mobile elements from the sediment-derived supercritical fluids. Separation of slab-derived supercritical fluids into melts and aqueous fluids can elucidate the two slab-derived components observed in subduction zone magma chemistry. PMID:23112158

Comparative Study on the Effects of Boiling, Steaming, Grilling, Microwaving and Superheated Steaming on Quality Characteristics of Marinated Chicken Steak

PubMed Central

Choi, Yun-Sang; Kim, Young-Boong; Jeon, Ki-Hong; Kim, Eun-Mi; Sung, Jung-Min; Kim, Hyun-Wook

2016-01-01

The effects of five different cooking methods (boiling, steaming, grilling, microwaving, and superheated steaming) on proximate composition, pH, color, cooking loss, textural properties, and sensory characteristics of chicken steak were studied. Moisture content and lightness value (L*-value) were higher in superheated steam cooked chicken steak than that of the other cooking treatments such as boiling, steaming, grilling and microwaving cooking (p<0.05), whereas protein content, redness value (a*-value), hardness, gumminess, and chewiness of superheated steam cooked chicken steak was lower than that in the other cooking treatments (p<0.05). Fat content and ash content, springiness, and cohesiveness were not significantly different among the chicken steak cooked using various methods (p>0.05). Among the sensory characteristics, tenderness score, juiciness score and overall acceptability score were the highest for the superheated steam samples (p<0.05), whereas no difference in flavor scores were observed among the other treatments (p>0.05). These results show that marinated chicken steak treated with superheated steam in a preheated 250℃ oven and 380℃ steam for 5 min until core temperature reached 75℃ improved the quality characteristics and sensory properties the best. Therefore, superheated steam was useful to improve cooked chicken steak. PMID:27499656

A Procedure for the supercritical fluid extraction of coal samples, with subsequent analysis of extracted hydrocarbons

USGS Publications Warehouse

Kolak, Jonathan J.

2006-01-01

Introduction: This report provides a detailed, step-by-step procedure for conducting extractions with supercritical carbon dioxide (CO2) using the ISCO SFX220 supercritical fluid extraction system. Protocols for the subsequent separation and analysis of extracted hydrocarbons are also included in this report. These procedures were developed under the auspices of the project 'Assessment of Geologic Reservoirs for Carbon Dioxide Sequestration' (see http://pubs.usgs.gov/fs/fs026-03/fs026-03.pdf) to investigate possible environmental ramifications associated with CO2 storage (sequestration) in geologic reservoirs, such as deep (~1 km below land surface) coal beds. Supercritical CO2 has been used previously to extract contaminants from geologic matrices. Pressure-temperature conditions within deep coal beds may render CO2 supercritical. In this context, the ability of supercritical CO2 to extract contaminants from geologic materials may serve to mobilize noxious compounds from coal, possibly complicating storage efforts. There currently exists little information on the physicochemical interactions between supercritical CO2 and coal in this setting. The procedures described herein were developed to improve the understanding of these interactions and provide insight into the fate of CO2 and contaminants during simulated CO2 injections.

Supercritical Fluid Extraction of Metal Chelate: A Review.

PubMed

Ding, Xin; Liu, Qinli; Hou, Xiongpo; Fang, Tao

2017-03-04

Supercritical fluid extraction (SFE), as a new green extraction technology, has been used in extracting various metal species. The solubilities of chelating agents and corresponding metal chelates are the key factors which influence the efficiency of SFE. Other main properties of them such as stability and selectivity are also reviewed. The extraction mechanisms of mainly used chelating agents are explained by typical examples in this paper. This is the important aspect of SFE of metal ions. Moreover, the extraction efficiencies of metal species also depend on other factors such as temperature, pressure, extraction time and matrix effect. The two main complexation methods namely in-situ and on-line chelating SFE are described in detail. As an efficient chelating agent, tributyl phosphate-nitric acid (TBP-HNO 3 ) complex attracts much attention. The SFE of metal ions, lanthanides and actinides as well as organometallic compounds are also summarized. With the proper selection of ligands, high efficient extraction of metal species can be obtained. As an efficient sample analysis method, supercritical fluid chromatography (SFC) is introduced in this paper. Recently, the extraction method combining ionic liquids (ILs) with supercritical fluid has been becoming a novel technology for treating metal ions. The kinetics related to SFE of metal species is discussed with some specific examples.

Thermochemically recuperated and steam cooled gas turbine system

DOEpatents

Viscovich, P.W.; Bannister, R.L.

1995-07-11

A gas turbine system is described in which the expanded gas from the turbine section is used to generate the steam in a heat recovery steam generator and to heat a mixture of gaseous hydrocarbon fuel and the steam in a reformer. The reformer converts the hydrocarbon gas to hydrogen and carbon monoxide for combustion in a combustor. A portion of the steam from the heat recovery steam generator is used to cool components, such as the stationary vanes, in the turbine section, thereby superheating the steam. The superheated steam is mixed into the hydrocarbon gas upstream of the reformer, thereby eliminating the need to raise the temperature of the expanded gas discharged from the turbine section in order to achieve effective conversion of the hydrocarbon gas. 4 figs.

Hockey-stick steam generator for LMFBR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hallinan, G.J.; Svedlund, P.E.

1981-01-01

This paper presents the criteria and evaluation leading to the selection of the Hockey Stick Steam Generator Concept and subsequent development of that concept for LMFBR application. The selection process and development of the Modular Steam Generator (MSG) is discussed, including the extensive test programs that culminated in the manufacture and test of a 35 MW(t) Steam Generator. The design of the CRBRP Steam Generator is described, emphasizing the current status and a review of the critical structural areas. CRBRP steam generator development tests are evaluated, with a discussion of test objectives and rating of the usefulness of test resultsmore » to the CRBRP prototype design. Manufacturing experience and status of the CRBRP prototype and plant units is covered. The scaleup of the Hockey Stick concept to large commercial plant application is presented, with an evaluation of scaleup limitations, transient effects, and system design implications.« less

[Optimization of supercritical fluid extraction of bioactive components in Ligusticum chuanxiong by orthogonal array design].

PubMed

Hu, Li-Cui; Wu, Xun; Yang, Xue-Dong

2013-10-01

With the yields of ferulic acid, coniferylferulate, Z-ligustilide, senkyunolide A, butylidenephthalide, butylphthalide, senkyunolide I, senkyunolide H, riligustilide, levistolide A, and total pharmacologically active ingredient as evaluation indexes, the extraction of Ligusticum chuanxiong by supercritical fluid technology was investigated through an orthogonal experiment L9 (3(4)). Four factors, namely temperature, pressure, flow rate of carbon dioxide, co-solvent concentration of the supercritical fluid, were investigated and optimized. Under the optimized conditions, namely 65 degrees C of temperature, 35 MPa of pressure, 1 L x min(-1) of CO2 flow rate, 8% of co-solvent concetration, supercritical fluid extraction could achieve a better yield than the conventional reflux extraction using methanol. And the supercritical fluid extraction process was validated to be stable and reliable.

Liposomes Size Engineering by Combination of Ethanol Injection and Supercritical Processing.

PubMed

Santo, Islane Espirito; Campardelli, Roberta; Albuquerque, Elaine Cabral; Vieira De Melo, Silvio A B; Reverchon, Ernesto; Della Porta, Giovanna

2015-11-01

Supercritical fluid extraction using a high-pressure packed tower is proposed not only to remove the ethanol residue from liposome suspensions but also to affect their size and distribution leading the production of nanosomes. Different operating pressures, temperatures, and gas to liquid ratios were explored and ethanol was successfully extracted up to a value of 400 ppm; liposome size and distribution were also reduced by the supercritical processing preserving their integrity, as confirmed by Z-potential data and Trasmission Electron Microscopy observations. Operating at 120 bar and 38°C, nanosomes with a mean diameter of about 180 ± 40 nm and good storage stability were obtained. The supercritical processing did not interfere on drug encapsulation, and no loss of entrapped drug was observed when the water-soluble fluorescein was loaded as a model compound. Fluorescein encapsulation efficiency was 30% if pure water was used during the supercritical extraction as processing fluid; whereas an encapsulation efficiency of 90% was obtained if the liposome suspension was processed in water/fluorescein solution. The described technology is easy to scale up to an industrial production and merge in one step the solvent extraction, liposome size engineering, and an excellent drug encapsulation in a single operation unit. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Laboratory testing of a supercritical helium pump for a magnetic refrigerator

NASA Technical Reports Server (NTRS)

Wang, Pao-Lien

1988-01-01

A supercritical helium testing system for a magnetic refrigerator has been built. Details of the supercritical helium pump, the test system, and the test instrumentation are given. Actual pump tests were not run during this ASEE term because of delivery problems associated with the required pump flow meter. Consequently, efforts were directed on preliminary design of the magnetic refrigeration system for the pump. The first concern with the magnetic refrigerator design was determining how to effectively make use of the pump. A method to incorporate the supercritical helium pump into a magnetic refrigerator was determined by using a computer model. An illustrated example of this procedure is given to provide a tool for sizing the magnetic refrigerator system as a function of the pump size. The function of the computer model and its operation are also outlined and discussed.

Disinfection of Cystoscopes by Subatmospheric Steam and Steam and Formaldehyde at 80°C

PubMed Central

Alder, V. G.; Gingell, J. C.; Mitchell, J. P.

1971-01-01

A new method of disinfection adapted for endoscopic instruments uses low temperature steam at 80°C or steam and formaldehyde at 80°C. The process has considerable advantages over existing methods and more closely approaches the ideal requirements. ImagesFIG. 3FIG. 4FIG. 5 PMID:5569551

Experimental trim drag values for conventional and supercritical wings. M.S. Thesis

NASA Technical Reports Server (NTRS)

Jacobs, P. F.

1981-01-01

Supercritical wings were studied to determine whether they incur higher trim drag values at cruise conditions than wide body technology wings. Relative trim drag increments were measured in an experimental wind tunnel investigation. The tests utilized high aspect ratio supercritical wing and a wide body wing in conjunction with five different horizontal tail configurations, mounted on a representative wide body fuselage. The three low tail configurations and two T tail configurations were chosen to measure the effects on horizontal tail size, location, and camber on the trim drag increments for the two wings. The increase in performance (lift to drag ratio) for supercritical wing over the wide body wing was 11 percent for both the optimum low tail and T tail configurations.

7 CFR 160.8 - Steam distilled wood turpentine.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 7 Agriculture 3 2014-01-01 2014-01-01 false Steam distilled wood turpentine. 160.8 Section 160.8... STANDARDS FOR NAVAL STORES General § 160.8 Steam distilled wood turpentine. The designation “steam distilled wood turpentine” shall refer to the kind of spirits of turpentine obtained by steam distillation from...

7 CFR 160.8 - Steam distilled wood turpentine.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 7 Agriculture 3 2012-01-01 2012-01-01 false Steam distilled wood turpentine. 160.8 Section 160.8... STANDARDS FOR NAVAL STORES General § 160.8 Steam distilled wood turpentine. The designation “steam distilled wood turpentine” shall refer to the kind of spirits of turpentine obtained by steam distillation from...

7 CFR 160.8 - Steam distilled wood turpentine.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 7 Agriculture 3 2013-01-01 2013-01-01 false Steam distilled wood turpentine. 160.8 Section 160.8... STANDARDS FOR NAVAL STORES General § 160.8 Steam distilled wood turpentine. The designation “steam distilled wood turpentine” shall refer to the kind of spirits of turpentine obtained by steam distillation from...

49 CFR 230.21 - Steam locomotive number change.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Steam locomotive number change. 230.21 Section 230... Recordkeeping Requirements § 230.21 Steam locomotive number change. When a steam locomotive number is changed... all documentation related to the steam locomotive by showing the old and new numbers: Old No. 000 New...

7 CFR 160.8 - Steam distilled wood turpentine.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 3 2010-01-01 2010-01-01 false Steam distilled wood turpentine. 160.8 Section 160.8... STANDARDS FOR NAVAL STORES General § 160.8 Steam distilled wood turpentine. The designation “steam distilled wood turpentine” shall refer to the kind of spirits of turpentine obtained by steam distillation from...

7 CFR 160.8 - Steam distilled wood turpentine.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 7 Agriculture 3 2011-01-01 2011-01-01 false Steam distilled wood turpentine. 160.8 Section 160.8... STANDARDS FOR NAVAL STORES General § 160.8 Steam distilled wood turpentine. The designation “steam distilled wood turpentine” shall refer to the kind of spirits of turpentine obtained by steam distillation from...

49 CFR 229.105 - Steam generator number.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Steam generator number. 229.105 Section 229.105....105 Steam generator number. An identification number shall be marked on the steam generator's separator and that number entered on FRA Form F 6180-49A. ...

49 CFR 229.105 - Steam generator number.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Steam generator number. 229.105 Section 229.105....105 Steam generator number. An identification number shall be marked on the steam generator's separator and that number entered on FRA Form F 6180-49A. ...

Widom Delta of Supercritical Gas-Liquid Coexistence.

PubMed

Ha, Min Young; Yoon, Tae Jun; Tlusty, Tsvi; Jho, Yongseok; Lee, Won Bo

2018-04-05

Density fluctuations and the Widom line are of great importance in understanding the critical phenomena and the behaviors of supercritical fluids (SCFs). We report on the direct classification of liquid-like and gas-like molecules coexisting in the SCF, identified by machine learning analysis on simulation data. The deltoid coexistence region encloses the Widom line and may therefore be termed the Widom delta. Number fractions of gas-like and liquid-like particles are found to undergo continuous transition across the delta, following a simplified two-state model. These fractions are closely related to the magnitude of supercritical anomaly, which originates from the fluctuation between the two types. This suggests a microscopic view of the SCF as a mixture of liquid-like and gas-like structures, providing an integrative explanation to the anomalous behaviors near the critical point and the Widom line.

The STEAM Project

NASA Astrophysics Data System (ADS)

von Schéele, F.; Steam Team

The proposed satellite project "Stratosphere-Troposphere Exchange And climate Monitor" (STEAM) is dedicated to the investigation of chemical, dynamical, and radiative processes in the upper troposphere and lower stratosphere (UT/LS) altitude range and their links with the Earth climate and stratosphere evolution. The main objectives are to provide vertically and horizontally resolved information on the global distributions of UT/LS key species such as H2O, O3, and CO, and global fields of O3, H2O and halogen compounds responsible for the O3 destruction like ClO in the stratosphere. The UT/LS region plays an important role in the Earth's climate system. Despite its importance there is still a lack of accurate, height-resolved data from the UT/LS. Confronting 3-D climate and chemical-transport models with STEAM observations will improve our knowledge of this atmospheric region. Furthermore, it will be important to continue monitoring the evolution of the stratosphere regarding the expected decline of halogen compounds and recovery of the ozone layer. STEAM consists of a microwave limb-sounding instrument, operating in the 320-360 GHz range to sound the UT/LS and in the 485-505 GHz range to sound the stratosphere, and an optical instrument. By sounding the Earth atmosphere's limb from 5 to 28 km employing a new technique with 8 simultaneous measurements, STEAM will produce a global dataset of UT/LS key species with high vertical (1.5-2.5 km) and horizontal (30-50 km) resolution. The sub-mm band will cover 15 to 40 km. An optical instrument, co-aligned with the mm-wave band, will support micro-wave measurements with cloud indications and in addition provide stratospheric ozone, and aerosol and cloud property measurements. STEAM, planned for a launch in 2008, will be a collaboration between laboratories, industry and agencies in several countries. The Odin heritage of the project (e.g. microwave and optical instruments) provides technical maturity and will help to keep

Preparing silica aerogel monoliths via a rapid supercritical extraction method.

PubMed

Carroll, Mary K; Anderson, Ann M; Gorka, Caroline A

2014-02-28

A procedure for the fabrication of monolithic silica aerogels in eight hours or less via a rapid supercritical extraction process is described. The procedure requires 15-20 min of preparation time, during which a liquid precursor mixture is prepared and poured into wells of a metal mold that is placed between the platens of a hydraulic hot press, followed by several hours of processing within the hot press. The precursor solution consists of a 1.0:12.0:3.6:3.5 x 10(-3) molar ratio of tetramethylorthosilicate (TMOS):methanol:water:ammonia. In each well of the mold, a porous silica sol-gel matrix forms. As the temperature of the mold and its contents is increased, the pressure within the mold rises. After the temperature/pressure conditions surpass the supercritical point for the solvent within the pores of the matrix (in this case, a methanol/water mixture), the supercritical fluid is released, and monolithic aerogel remains within the wells of the mold. With the mold used in this procedure, cylindrical monoliths of 2.2 cm diameter and 1.9 cm height are produced. Aerogels formed by this rapid method have comparable properties (low bulk and skeletal density, high surface area, mesoporous morphology) to those prepared by other methods that involve either additional reaction steps or solvent extractions (lengthier processes that generate more chemical waste).The rapid supercritical extraction method can also be applied to the fabrication of aerogels based on other precursor recipes.

Preparing Silica Aerogel Monoliths via a Rapid Supercritical Extraction Method

PubMed Central

Gorka, Caroline A.

2014-01-01

A procedure for the fabrication of monolithic silica aerogels in eight hours or less via a rapid supercritical extraction process is described. The procedure requires 15-20 min of preparation time, during which a liquid precursor mixture is prepared and poured into wells of a metal mold that is placed between the platens of a hydraulic hot press, followed by several hours of processing within the hot press. The precursor solution consists of a 1.0:12.0:3.6:3.5 x 10-3 molar ratio of tetramethylorthosilicate (TMOS):methanol:water:ammonia. In each well of the mold, a porous silica sol-gel matrix forms. As the temperature of the mold and its contents is increased, the pressure within the mold rises. After the temperature/pressure conditions surpass the supercritical point for the solvent within the pores of the matrix (in this case, a methanol/water mixture), the supercritical fluid is released, and monolithic aerogel remains within the wells of the mold. With the mold used in this procedure, cylindrical monoliths of 2.2 cm diameter and 1.9 cm height are produced. Aerogels formed by this rapid method have comparable properties (low bulk and skeletal density, high surface area, mesoporous morphology) to those prepared by other methods that involve either additional reaction steps or solvent extractions (lengthier processes that generate more chemical waste).The rapid supercritical extraction method can also be applied to the fabrication of aerogels based on other precursor recipes. PMID:24637334

STEAM Enacted: A Case Study of a Middle School Teacher Implementing STEAM Instructional Practices

ERIC Educational Resources Information Center

Herro, Danielle; Quigley, Cassie

2016-01-01

This paper examines the implementation practices of a 6th grade middle school teacher enacting STEAM (science, technology, engineering, art and math) teaching in his classroom after participating in a 45-hour STEAM professional development. Case study is used to detail the process, successes, and challenges. Project-based learning, technology…

Optimization and Comparison of Direct and Indirect Supercritical Carbon Dioxide Power Plant Cycles for Nuclear Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Edwin A. Harvego; Michael G. McKellar

2011-11-01

There have been a number of studies involving the use of gases operating in the supercritical mode for power production and process heat applications. Supercritical carbon dioxide (CO2) is particularly attractive because it is capable of achieving relatively high power conversion cycle efficiencies in the temperature range between 550 C and 750 C. Therefore, it has the potential for use with any type of high-temperature nuclear reactor concept, assuming reactor core outlet temperatures of at least 550 C. The particular power cycle investigated in this paper is a supercritical CO2 Recompression Brayton Cycle. The CO2 Recompression Brayton Cycle can bemore » used as either a direct or indirect power conversion cycle, depending on the reactor type and reactor outlet temperature. The advantage of this cycle when compared to the helium Brayton cycle is the lower required operating temperature; 550 C versus 850 C. However, the supercritical CO2 Recompression Brayton Cycle requires an operating pressure in the range of 20 MPa, which is considerably higher than the required helium Brayton cycle operating pressure of 8 MPa. This paper presents results of analyses performed using the UniSim process analyses software to evaluate the performance of both a direct and indirect supercritical CO2 Brayton Recompression cycle for different reactor outlet temperatures. The direct supercritical CO2 cycle transferred heat directly from a 600 MWt reactor to the supercritical CO2 working fluid supplied to the turbine generator at approximately 20 MPa. The indirect supercritical CO2 cycle assumed a helium-cooled Very High Temperature Reactor (VHTR), operating at a primary system pressure of approximately 7.0 MPa, delivered heat through an intermediate heat exchanger to the secondary indirect supercritical CO2 Brayton Recompression cycle, again operating at a pressure of about 20 MPa. For both the direct and indirect cycles, sensitivity calculations were performed for reactor outlet

Evaluation of on-line chelant addition to PWR steam generators. Steam generator cleaning project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tvedt, T.J.; Wallace, S.L.; Griffin, F. Jr.

1983-09-01

The investigation of chelating agents for continuous water treatment of secondary loops of PWR steam generators were conducted in two general areas: the study of the chemistry of chelating agents and the study of materials compatability with chelating agents. The thermostability of both EDTA and HEDTA metal chelates in All Volatile Treatment (AVT) water chemistry were shown to be greater than or equal to the thermostability of EDTA metal chelates in phosphate-sulfite water chemistry. HEDTA metal chelates were shown to have a much greater stability than EDTA metal chelates. Using samples taken from the EDTA metal chelate thermostability study andmore » from the Commonwealth Research Corporation (CRC) model steam generators (MSG), EDTA decomposition products were determined. Active metal surfaces were shown to become passivated when exposed to EDTA and HEDTA concentrations as high as 0.1% w/w in AVT. Trace amounts of iron in the water were found to increase the rate of passivation. Material balance and visual inspection data from CRC model steam generators showed that metal was transported through and cleaned from the MSG's. The Inconel 600 tubes of the salt water fouled model steam generators experienced pitting corrosion. Results of this study demonstrates the feasibility of EDTA as an on-line water treatment additive to maintain nuclear steam generators in a clean condition.« less

The enigmatic ultra-long run-out of seafloor density driven flows

NASA Astrophysics Data System (ADS)

Dorrell, R. M.

2017-12-01

Dilute, particulate-laden, density-driven flows - turbidity currents - are a predominant mechanism for transporting sediment from source to sink in deep marine environments. These flows sculpt channels on the seafloor and, as evidenced by a wealth of bathymetric data, can travel for >1000km, forming some of the largest sedimentary landforms on the planet. For turbidity currents to travel such large dsitances, sediment must be self-maintained in suspension, i.e., be in a state of autosuspension. It has been shown that such self-maintained sediment suspensions can only occur whilst inertial forces are greater than gravitational forces, entailing supercritical flow. This conclusion is paradoxical, as inertia dominated flows rapidly entrain fluid, thereby thickening and slowing to become subcritical. However, current theory can only truly be applied to the proximal upper slope regions of seafloor channels where incised flows are fully confined. This contrasts with the distal reaches of long run out turbidity current systems, where the flow is only partially confined through self-channelization. Here it is shown that overspill of partially confined flow has a significant effect on the hydro- and morphodynamics of turbidity current systems. A new model is derived that shows that channel overspill acts to negate the effects of ambient fluid entrainment: a dynamic balance that limits increases in flow depth and maintains supercritical flow throughout the channel. In the new model mass, momentum and energy conservation is modulated by flow overspill onto channel banks, necessarily requiring description of the vertical structure of the flow. Analysis of continuously stratified steady state flow dynamics shows that the integration of overspill and stratification is necessary to enable maintained autosuspension and thus predict the ultra-long run-out of turbidity currents.

Supercritical Saltwater Spray for Marine Cloud Brightening (MCB)

NASA Astrophysics Data System (ADS)

Neukermans, A.; Cooper, G. F.; Foster, J.; Galbraith, L. K.; Johnston, D.; Ormond, B.; Wang, Q.

2012-12-01

Solar Radiation Management (SRM), including both stratospheric sulfur aerosol delivery and MCB, has emerged as the leading contender for geoengineering. Field research in MCB would require a technique capable of producing 1017 salt nuclei/sec from a single source on a seagoing vessel. Spraying supercritical saltwater has emerged as a viable technology, at least for research purposes. Under optimum conditions a single 50-μm nozzle produces 1014 suitable nuclei/sec. Power consumption is high (1-2 MW), but 95% of the required energy is in the form of heat that can probably be obtained from wasted ship-engine heat. While its implementation is conceptually simple, the corrosive nature of supercritical saltwater makes the material requirements very demanding. Progress on this work is detailed.

Forensic applications of supercritical fluid chromatography - mass spectrometry.

PubMed

Pauk, Volodymyr; Lemr, Karel

2018-06-01

Achievements of supercritical fluid chromatography with mass spectrometric detection made in the field of forensic science during the last decade are reviewed. The main topics include analysis of traditional drugs of abuse (e.g. cannabis, methamphetamine) as well as new psychoactive substances (synthetic cannabinoids, cathinones and phenethylamines), doping agents (anabolic steroids, stimulants, diuretics, analgesics etc.) and chemical warfare agents. Control of food authenticity, detection of adulteration and identification of toxic substances in food are also pointed out. Main aspects of an analytical workflow, such as sample preparation, separation and detection are discussed. A special attention is paid to the performance characteristics and validation parameters of supercritical fluid chromatography-mass spectrometric methods in comparison with other separation techniques. Copyright © 2018 Elsevier B.V. All rights reserved.

Inhibition effect in supercritical water oxidation of hydroquinone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thammanayakatip, C.; Oshima, Yoshito; Koda, Seiichiro

1998-05-01

In the oxidation reactions of hydroquinone under a supercritical conditions (temperature of 683 K and pressure of 24.5 MPa), the conversion was found to become saturated despite the very fast initial reaction. This behavior was quite different from that under a subcritical condition (temperature of 633 K and pressure of 24.5 MPa). Under both conditions, p-benzoquinone was found to be an important intermediate. The yield of CO{sub 2} was very small, which indicates a strong inhibition effect of hydroquinone and/or its derivatives. These inhibition phenomena should be taken into account very carefully in the application of supercritical water oxidation formore » treating waste organic materials where a complete decomposition is very important.« less

Supercritical fluid regeneration of adsorbents

NASA Astrophysics Data System (ADS)

Defilippi, R. P.; Robey, R. J.

1983-05-01

The results of a program to perform studies supercritical (fluid) carbon dioxide (SCF CO2) regeneration of adsorbents, using samples of industrial wastewaters from manufacturing pesticides and synthetic solution, and to estimate the economics of the specific wastewater treatment regenerations, based on test data are given. Processing costs for regenerating granular activated carbon GAC) for treating industrial wastewaters depend on stream properties and regeneration throughput.

Use of liquid/supercritical CO2 extraction process for butanol recovery from fermentation broth

USDA-ARS?s Scientific Manuscript database

In order for butanol fermentation to be a viable option, it is essential to recover it from fermentation broth using economical alternate in-situ product recovery techniques such as liquid/supercritical CO2 extraction as compared to distillation. This technique (liquid CO2 extraction & supercritical...

Driving Forces Controlling Host-Guest Recognition in Supercritical Carbon Dioxide Solvent.

PubMed

Ingrosso, Francesca; Altarsha, Muhannad; Dumarçay, Florence; Kevern, Gwendal; Barth, Danielle; Marsura, Alain; Ruiz-López, Manuel F

2016-02-24

The formation of supramolecular host-guest complexes is a very useful and widely employed tool in chemistry. However, supramolecular chemistry in non-conventional solvents such as supercritical carbon dioxide (scCO2 ), one of the most promising sustainable solvents, is still in its infancy. In this work, we explored a successful route to the development of green processes in supercritical CO2 by combining a theoretical approach with experiments. We were able to synthesize and characterize an inclusion complex between a polar aromatic molecule (benzoic acid) and peracetylated-β-cyclodextrin, which is soluble in the supercritical medium. This finding opens the way to wide, environmental friendly, applications of scCO2 in many areas of chemistry, including supramolecular synthesis, reactivity and catalysis, micro and nano-particle formation, molecular recognition, as well as enhanced extraction processes with increased selectivity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Benchmark of ReaxFF force field for subcritical and supercritical water.

PubMed

Manzano, Hegoi; Zhang, Weiwei; Raju, Muralikrishna; Dolado, Jorge S; López-Arbeloa, Iñigo; van Duin, Adri C T

2018-06-21

Water in the subcritical and supercritical states has remarkable properties that make it an excellent solvent for oxidation of hazardous chemicals, waste separation, and green synthesis. Molecular simulations are a valuable complement to experiments in order to understand and improve the relevant sub- and super-critical reaction mechanisms. Since water molecules under these conditions can act not only as a solvent but also as a reactant, dissociative force fields are especially interesting to investigate these processes. In this work, we evaluate the capacity of the ReaxFF force field to reproduce the microstructure, hydrogen bonding, dielectric constant, diffusion, and proton transfer of sub- and super-critical water. Our results indicate that ReaxFF is able to simulate water properties in these states in very good quantitative agreement with the existing experimental data, with the exception of the static dielectric constant that is reproduced only qualitatively.

The effect of supercritical helium natural convection on the temperature stabilityin a cryogenic system

NASA Astrophysics Data System (ADS)

Sun, Y.; Zhou, G.; Li, K. R.; Li, Q.; Pan, W.

2017-12-01

With high specific heat and density, supercritical helium can be used to reduce the temperature oscillationand improve temperature stabilityin the low temperature conditions. However, the natural convection ofthe supercritical helium has a complex influence on the suppression of the temperature oscillation. In this paper,a transient three-dimensional numerical simulation is carried out for the natural convection in the cylinder to analyze the effect of natural convection on transferring of temperature oscillation.According to the results of numerical calculation, a cryogenic system cooled by GM cryocooler is designed tostudy the influence of natural convection of supercritical helium on temperature oscillation suppression.

The ultrasonic-enhanced factor of mass-transfer coefficient in the supercritical carbon dioxide extraction

NASA Astrophysics Data System (ADS)

Luo, Benyi; Lu, Yigang

2008-10-01

Based on several hypotheses about the process of supercritical carbon dioxide extraction, the onflow around the solute granule is figured out by the Navier-Stocks equation. In combination with the Higbie’s solute infiltration model, the link between the mass-transfer coefficient and the velocity of flow is found. The mass-transfer coefficient with the ultrasonical effect is compared with that without the ultrasonical effect, and then a new parameter named the ultrasonic-enhanced factor of mass-transfer coefficient is brought forward, which describes the mathematical model of the supercritical carbon dioxide extraction process enhanced by ultrasonic. The model gives out the relationships among the ultrasonical power, the ultrasonical frequency, the radius of solute granule and the ultrasonic-enhanced factor of mass-transfer coefficient. The results calculated by this model fit well with the experimental data, including the extraction of Coix Lacryma-jobi Seed Oil (CLSO) and Coix Lacryma-jobi Seed Ester (CLSE) from coix seeds and the extraction of Eicosapentaenoic Acid (EPA) and Docosahexaenoic Acid (DHA) from the alga by means of the ultrasonic-enhanced supercritical carbon dioxide extraction (USFE) and the supercritical carbon dioxide extraction (SFE) respectively. This proves the rationality of the ultrasonic-enhanced factor model. The model provides a theoretical basis for the application of ultrasonic-enhanced supercritical fluid extraction technique.

Supercritical fluid extraction of 11C-labeled metabolites in tissue using supercritical ammonia.

PubMed

Jacobson, G B; Moulder, R; Lu, L; Bergström, M; Markides, K E; Långström, B

1997-02-01

Supercritical fluid extraction (SFE) of 11C-labeled tracer compounds and their metabolites from biological tissue was performed using supercritical ammonia in an attempt to develop a rapid extraction procedure that allowed subsequent analysis of the labeled metabolites. Metabolites were extracted from kidneys and brain in rats given in vivo injections of the radiotracers O-[2-11C]acetyl-L-carnitine and N-[11C]methylpiperidyl benzilate, respectively. Only a minimal sample pretreatment of the tissue was necessary, i.e., cutting into 10-20 pieces and mixing with the drying agent Hydromatrix, before it was loaded into the extraction vessel. Extraction efficiency was measured for SFE at temperatures over the range of 70-150 degrees C and a pressure of 400 bar. For O-[2-11C]acetyl-L-carnitine, 66% of the radioactivity was trapped in the collected fractions and 12% remained in the extraction vessel. For the more lipophilic N-[11C]methylpiperidyl benzilate, 93% of the activity was collected and less than 1% remained in the extraction vessel. Labeled metabolites were analyzed by LC and also, in the case, of O-[2-11C]acetyl-L-carnitine by LC/MS. The complete extraction procedure, from removal of the biological tissue until an extract was ready for analysis, was 25 min, corresponding to about one half-life of the radionuclide 11C.

Variable effect of steam injection level on beef muscles: semitendinosus and biceps femoris cooked in convection-steam oven.

PubMed

Zając, Marzena; Kącik, Sławomir; Palka, Krystyna; Widurek, Paweł

2015-01-01

Combi ovens are used very often in restaurants to heat up food. According to the producers the equipment allows to cook meat portions which are more tender and flavoursome comparing to conventional cooking techniques. Beef steaks from muscles semitendinosus and biceps femoris were cooked in convection-steam oven at three humidity levels: 10, 60 and 100%. Chemical composition, including total and insoluble collagen content and cook losses were analysed along with the texture and colour parameters. M. biceps femoris was the hardest and the most chewy at 100% steam saturation level and hardness measured for m. semitendinosus was the lowest at 10% of vapour injection. Changing the steam conditions in the oven chamber did not affect the detectable colour differences of m. biceps femoris, but it was significant for m. semitendinosus. Applying 100% steam saturation caused higher cook losses and the increase of insoluble collagen fractions in both analysed muscles. The results are beneficial for caterers using steam-convection ovens in terms of providing evidence that the heating conditions should be applied individually depending on the muscle used. The tenderness of m. semitendinosus muscle cooked at 10% steam saturation level was comparable to the tenderness obtained for the same muscle aged for 10 days and cooked with 100% steam saturation. Steaks from m. biceps femoris muscle should be cooked with maximum 60% saturation level to obtain higher tenderness.

In situ analysis of chemical components induced by steaming between fresh ginseng, steamed ginseng, and red ginseng.

PubMed

In, Gyo; Ahn, Nam-Geun; Bae, Bong-Seok; Lee, Myoung-Woo; Park, Hee-Won; Jang, Kyoung Hwa; Cho, Byung-Goo; Han, Chang Kyun; Park, Chae Kyu; Kwak, Yi-Seong

2017-07-01

The chemical constituents of Panax ginseng are changed by processing methods such as steaming or sun drying. In the present study, the chemical change of Panax ginseng induced by steaming was monitored in situ . Samples were separated from the same ginseng root by incision during the steaming process, for in situ monitoring. Sampling was sequentially performed in three stages; FG (fresh ginseng) → SG (steamed ginseng) → RG (red ginseng) and 60 samples were prepared and freeze dried. The samples were then analyzed to determine 43 constituents among three stages of P. ginseng . The results showed that six malonyl-ginsenoside (Rg1, Rb1, Rb3, Rc, Rd, Rb2) and 15 amino acids were decreased in concentration during the steaming process. In contrast, ginsenoside-Rh1, 20( S )-Rg2, 20( S, R )-Rg3 and Maillard reaction product such as AF (arginine-fructose), AFG (arginine-fructose-glucose), and maltol were newly generated or their concentrations were increased. This study elucidates the dynamic changes in the chemical components of P. ginseng when the steaming process was induced. These results are thought to be helpful for quality control and standardization of herbal drugs using P. ginseng and they also provide a scientific basis for pharmacological research of processed ginseng (Red ginseng).

Measurement of diffusion in fluid systems: Applications to the supercritical fluid region

NASA Astrophysics Data System (ADS)

Bruno, Thomas J.

1994-04-01

The experimental procedures that are applicable to the measurement of diffusion in supercritical fluid solutions are reviewed. This topic is of great importance to the proper design of advanced aircraft and turbine fuels, since the fuels on these aircraft may sometimes operate under supercritical fluid conditions. More specifically, we will consider measurements of the binary interaction diffusion coefficient D exp 12 of a solute (species 1) and the solvent (species 2). In this discussion, the supercritical fluid is species 2, and the solute, species 1, will be at a relatively low concentration, sometimes approaching infinite dilution. After a brief introduction to the concept of diffusion, we will discuss in detail the use of chromatographic methods, and then briefly treat light scattering, nuclear magnetic resonance spectra, and physical methods.

[Study on the dynamic model with supercritical CO2 fluid extracting the lipophilic components in Panax notoginseng].

PubMed

Duan, Xian-Chun; Wang, Yong-Zhong; Zhang, Jun-Ru; Luo, Huan; Zhang, Heng; Xia, Lun-Zhu

2011-08-01

To establish a dynamics model for extracting the lipophilic components in Panax notoginseng with supercritical carbon dioxide (CO2). Based on the theory of counter-flow mass transfer and the molecular mass transfer between the material and the supercritical CO2 fluid under differential mass-conservation equation, a dynamics model was established and computed to compare forecasting result with the experiment process. A dynamics model has been established for supercritical CO2 to extract the lipophilic components in Panax notoginseng, the computed result of this model was consistent with the experiment process basically. The supercritical fluid extract dynamics model established in this research can expound the mechanism in the extract process of which lipophilic components of Panax notoginseng dissolve the mass transfer and is tallied with the actual extract process. This provides certain instruction for the supercritical CO2 fluid extract' s industrialization enlargement.

Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials

PubMed Central

Stadie, Nicholas P.; Callini, Elsa; Mauron, Philippe; Borgschulte, Andreas; Züttel, Andreas

2015-01-01

Supercritical fluid extraction and drying methods are well established in numerous applications for the synthesis and processing of porous materials. Herein, nitrogen is presented as a novel supercritical drying fluid for specialized applications such as in the processing of reactive porous materials, where carbon dioxide and other fluids are not appropriate due to their higher chemical reactivity. Nitrogen exhibits similar physical properties in the near-critical region of its phase diagram as compared to carbon dioxide: a widely tunable density up to ~1 g ml-1, modest critical pressure (3.4 MPa), and small molecular diameter of ~3.6 Å. The key to achieving a high solvation power of nitrogen is to apply a processing temperature in the range of 80-150 K, where the density of nitrogen is an order of magnitude higher than at similar pressures near ambient temperature. The detailed solvation properties of nitrogen, and especially its selectivity, across a wide range of common target species of extraction still require further investigation. Herein we describe a protocol for the supercritical nitrogen processing of porous magnesium borohydride. PMID:26066492

Equations for calculating the properties of dissociated steam

NASA Astrophysics Data System (ADS)

Aminov, R. Z.; Gudym, A. A.

2017-08-01

The equations of state for dissociated steam have been developed in the temperature and pressure ranges of 1250-2300 K and 0.01-10.00 MPa for calculating thermodynamic processes in thermal power units operating on high-temperature steam. These equations are based on the property tables for dissociated steam derived at a reference temperature of 0 K. It is assumed that the initial substance is steam, the dissociation of which—in accordance with the most likely chemical reactions—results in formation of molecules of hydrogen, oxygen, steam, hydroxyl, and atoms of oxygen and hydrogen. Differential thermodynamic correlations, considering a change in the chemical potential and the composition of the mixture, during the steam dissociation are used. A reference temperature of 0.01°C used in the calculation of parameters of nondissociated steam has been adopted to predict processes in thermal power units without matching the reference temperatures and to account for transformation of dissociated steam into its usual form for which there is the international system of equations with the water triple point of 0.01°C taken as the reference. In the investigated region, the deviation of dissociated steam properties from those of nondissociated steam, which increases with decreasing the pressure or increasing the temperature, was determined. For a pressure of 0.02 MPa and a temperature of 2200 K, these deviations are 512 kJ/kg for the enthalpy, 0.2574 kJ/(kg K) for the entropy, and 3.431 kJ/(kg K) for the heat capacity at constant pressure. The maximum deviation of the dissociated steam properties calculated by the developed equations from the handbook values that these equations are based on does not exceed 0.03-0.05%.

Operational experience with the supercritical helium during the TF coils tests campaign of SST-1

NASA Astrophysics Data System (ADS)

Panchal, Rohitkumar Natvarlal; Patel, Rakesh; Tank, Jignesh; Mahesuria, Gaurang; Sonara, Dashrath; Tanna, Vipul; Patel, Jayant; Srikanth, G. L. N.; Singh, Manoj; Patel, Ketan; Christian, Dikens; Garg, Atul; Bairagi, Nitn; Gupta, Manoj Kumar; Nimavat, Hiren; Shah, Pankil; Sharma, Rajiv; Pradhan, Subrata

2012-06-01

Under the 'SST-1 mission mandate' recently, all the sixteen Steady State Superconducting Tokamak (SST-1) Toroidal Field (TF) magnets have been successfully tested at their nominal currents of 10000 A in cold under supercritical helium (SHe) flow conditions. The TF magnets test campaign have begun in an experimental cryostat since June 2010 with the SST-1 Helium cryogenics facility, which is a 1.3 kW at 4.5 K helium refrigerator-cum-liquefier (HRL) system. The HRL provides ~300 g-s-1supercritical helium (SHe) with cold circulator (CC) as well as ~ 60 g-s-1 without cold circulator to fulfill the forced flow cooling requirements of SST- 1 magnets. In case of single TF coil tests, we can adjust HRL process parameters such that an adequate amount of required supercritical helium is available without the cold circulator. In this paper, the complete process is describing the Process Flow Diagram (PFD) of 1.3 kW at 4.5 K HRL, techniques to generate supercritical helium without using the cold-circulator and the results of the cooldown, steady state characteristics and experience of supercritical helium operations during the TF coils test campaign have been discussed.

Steam-assisted hot-pressing of construction plywood

Treesearch

Ronald W. Jokerst; Robert L. Geimer

1994-01-01

This study was designed to determine if steam injection pressing used for fiberboard, particleboard, and flakeboard could be adapted to the pressing of plywood. Plywood panels were fabricated with and without adhesive and then pressed to determine the effects of steam injection Lime, steam injection pressure, and press pressure on heat transfer rate, moisture...

Dehumidification System with Steam Permeability Films

NASA Astrophysics Data System (ADS)

Ishikwa, Masaaki; Sekimori, Souji; Ogiwara, Shigeaki; Ochiai, Tetsunari; Hirata, Tetsuo

In a factory with a clean room facility in cold regions, dew-condensation on walls of the facility is one of the most serious problems in winter. In this study, a new dehumidification system in which a steam permeability film is located between humid air in a clean room and dry air from outside to exchange steam is proposed. This system can treat a lot of humid air with small energy only for driving fans to flow air. Some films are examined in two kinds of steam exchangers; double tube type and flat p1ate type. Steam permeability resistance and therma1 resistance of each film are first obtained in a double tube type exchanger. An analytica1 model for a flat plate type exchanger is then proposed, which shows good agreement with experimental data. Steam and heat transfer characteristics of a flat plate type exchanger are also evaluated experimentally. One film on a flat plate type exchanger shows dehumidification capacity of 0.033g/s(=120g/h )with its area of 2.232m2.

Steam distillation extraction of ginger essential oil: Study of the effect of steam flow rate and time process

NASA Astrophysics Data System (ADS)

Fitriady, Muhammad Arifuddin; Sulaswatty, Anny; Agustian, Egi; Salahuddin, Aditama, Deska Prayoga Fauzi

2017-01-01

In Indonesia ginger was usually used as a seasoning for dishes, an ingredient for beverage and a source of herbal medicines. Beside raw usage, ginger can be processed to obtain the essential oil which has many advantages such as proven to be an active antimicrobial and having an antioxidant ability. There are a lot of methods to extract essential oil from ginger, one of which is steam distillation. The aim of the current study was to investigate the effect of variation of time process and steam flow rate in the yield on ginger essential oil steam distillation extraction process. It was found that the best operation condition was 0.35 ml/s as the steam flow rate which yields 2.43% oil. The optimum time process was predicted at 7.5 hours. The composition of the oil was varied depend on the flow rate and every flow rate has its own major component contained in the oil. Curcumene composition in the oil was increased as increased steam flow rate applied, but the composition of camphene was decreased along with the increasing steam flow rate.

Steam reformer with catalytic combustor

DOEpatents

Voecks, Gerald E.

1990-03-20

A steam reformer is disclosed having an annular steam reforming catalyst bed formed by concentric cylinders and having a catalytic combustor located at the center of the innermost cylinder. Fuel is fed into the interior of the catalytic combustor and air is directed at the top of the combustor, creating a catalytic reaction which provides sufficient heat so as to maintain the catalytic reaction in the steam reforming catalyst bed. Alternatively, air is fed into the interior of the catalytic combustor and a fuel mixture is directed at the top. The catalytic combustor provides enhanced radiant and convective heat transfer to the reformer catalyst bed.

Steam reformer with catalytic combustor

NASA Technical Reports Server (NTRS)

Voecks, Gerald E. (Inventor)

1990-01-01

A steam reformer is disclosed having an annular steam reforming catalyst bed formed by concentric cylinders and having a catalytic combustor located at the center of the innermost cylinder. Fuel is fed into the interior of the catalytic combustor and air is directed at the top of the combustor, creating a catalytic reaction which provides sufficient heat so as to maintain the catalytic reaction in the steam reforming catalyst bed. Alternatively, air is fed into the interior of the catalytic combustor and a fuel mixture is directed at the top. The catalytic combustor provides enhanced radiant and convective heat transfer to the reformer catalyst bed.

Origin and transport of chloride in superheated geothermal steam

USGS Publications Warehouse

Truesdell, A.H.; Haizlip, J.R.; Armannsson, H.; D'Amore, F.

1989-01-01

Hydrogen chloride (HCl) is a known component of some volcanic gases and volcanic-related hydrothermal systems. It has recently been discovered in superheated steam in exploited geothermal systems, usually as a result of HCl-induced corrosion of well casing and steam gathering systems. Evaluation of four geothermal systems (Tatun, Taiwan; Krafla, Iceland; Larderello, Italy and The Geysers, USA) which produce CI-bearing steam provides evidence for the presence of Cl as HCl and the natural reservoir conditions which can produce HCl-bearing steam. Theoretical calculations defining the physical and chemical conditions of the reservoir liquid which can produce HCl-bearing steam are presented. The main factors are pH, temperature and Cl concentration. Lower pH, higher temperature and higher chlorinity allow more HCl to be volatilized with steam. In order to reach the surface in steam, the HCl cannot contact liquid water in which it is more soluble, essentially limiting transport to superheated steam. Temperature, pH and Cl concentration of reservoir liquids in each of the geothermal systems evaluated combine differently to produce HCl-bearing steam. ?? 1989.

Comparative evaluation of surface and downhole steam-generation techniques

NASA Astrophysics Data System (ADS)

Hart, C.

The application of heat to reservoirs containing high API gravity oils can substantially improve recovery. Although steam injection is currently the principal thermal recovery method, heat transmission losses associated with delivery of the steam from the surface generators to the oil bearing formation has limited conventional steam injection to shallow reservoirs. The objective of the Department of Energy's Project DEEP STEAM is to develop the technology required to economically produce heavy oil from deep reservoirs. The tasks included in this effort are the development and evaluation of thermally efficient delivery systems and downhole steam generation systems. The technical and economic performance of conventional surface steam drives, which are strongly influenced by heat losses are compared. The selection of a preferred technology based upon either total efficiency or cost is found to be strongly influenced by reservoir depth, steam mass flow rate, and sandface steam quality.

Recuperative supercritical carbon dioxide cycle

DOEpatents

Sonwane, Chandrashekhar; Sprouse, Kenneth M; Subbaraman, Ganesan; O'Connor, George M; Johnson, Gregory A

2014-11-18

A power plant includes a closed loop, supercritical carbon dioxide system (CLS-CO.sub.2 system). The CLS-CO.sub.2 system includes a turbine-generator and a high temperature recuperator (HTR) that is arranged to receive expanded carbon dioxide from the turbine-generator. The HTR includes a plurality of heat exchangers that define respective heat exchange areas. At least two of the heat exchangers have different heat exchange areas.

Scaling considerations for a multi-megawatt class supercritical CO2 brayton cycle and commercialization.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fleming, Darryn D.; Holschuh, Thomas Vernon,; Conboy, Thomas M.

2013-11-01

Small-scale supercritical CO2 demonstration loops are successful at identifying the important technical issues that one must face in order to scale up to larger power levels. The Sandia National Laboratories supercritical CO2 Brayton cycle test loops are identifying technical needs to scale the technology to commercial power levels such as 10 MWe. The small size of the Sandia 1 MWth loop has demonstration of the split flow loop efficiency and effectiveness of the Printed Circuit Heat Exchangers (PCHXs) leading to the design of a fully recuperated, split flow, supercritical CO2 Brayton cycle demonstration system. However, there were many problems thatmore » were encountered, such as high rotational speeds in the units. Additionally, the turbomachinery in the test loops need to identify issues concerning the bearings, seals, thermal boundaries, and motor controller problems in order to be proved a reliable power source in the 300 kWe range. Although these issues were anticipated in smaller demonstration units, commercially scaled hardware would eliminate these problems caused by high rotational speeds at small scale. The economic viability and development of the future scalable 10 MWe solely depends on the interest of DOE and private industry. The Intellectual Property collected by Sandia proves that the ~10 MWe supercritical CO2 power conversion loop to be very beneficial when coupled to a 20 MWth heat source (either solar, geothermal, fossil, or nuclear). This paper will identify a commercialization plan, as well as, a roadmap from the simple 1 MWth supercritical CO2 development loop to a power producing 10 MWe supercritical CO2 Brayton loop.« less

Numerical investigation on cryogenic liquid jet under transcritical and supercritical conditions

NASA Astrophysics Data System (ADS)

Li, Liang; Xie, Maozhao; Wei, Wu; Jia, Ming; Liu, Hongsheng

2018-01-01

Cryogenic fluid injection and mixing under transcritical and supercritical conditions is numerically investigated with emphasis on the difference of the mechanism and characteristics between the two injections. A new solver is developed which is capable of handling the nonideality of the equation of state and the anomalies in fluid transport properties and is incorporated into the CFD software OpenFOAM. The new solver has been validated against available experimental data and exhibits a good performance. Computational results indicates that the differences between transcritical and supercritical injections are mainly induced by the pseudo-boiling phenomenon, resulting in that the transcritical jet has a longer cold liquid core and an isothermal expansion occurs at the surface of the cold core. The thickness of the supercritical mixing layer and its increase value along the jet direction are greater than its transcritical counterpart. The high-temperature jet whose initial temperature is above the pseudo-boiling temperature has the ability of enhancing the mixing of the jet with the surrounding gas.

Subcritical and supercritical interplanetary shocks - Magnetic field and energetic particle observations

NASA Technical Reports Server (NTRS)

Bavassano-Cattaneo, M. B.; Tsurutani, B. T.; Smith, E. J.; Lin, R. P.

1986-01-01

A study of 34 forward interplanetary shocks observed by ISEE 3 during 1978 and 1979 has been conducted. Magnetic field and high-energy particle data have been used, and for each shock the first critical Mach number has been determined. The first surprising result is that the majority of the observed shocks appear to be supercritical, and consistent with their supercritical character, many shocks have a foot and/or an overshoot in the magnetic field structure. Large-amplitude low-frequency waves (period of about 20 s in the spacecraft frame) are commonly observed upstream of all supercritical shocks (except for a few quasi-perpendicular shocks) and also upstream of the few subcritical shocks. Intense particle events are frequently observed at many shocks: spikes at quasi-perpendicular shocks and energetic storm particle events associated with quasi-parallel shocks can be comparably intense. The correlation of the high-energy particle peak flux with various shock parameters is in agreement with the acceleration mechanisms proposed by previous studies.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holcomb, Gordon R.

A presentation of the US-UK Phase 3 Task 1 Oxidation in Supercritical Fluids. Includes slides on Supercritical Steam, sCO 2 Power Cycles – Indirect, sCO 2 Power Cycles – Direct, Experimental Exposures, Alloys, Why Si, Results—Ni-xCr Alloys (5-24Cr), Fatigue Crack Growth$-$Experiment, and Alloys and Samples, Fatigue Crack Growth—Results (H282).

Valorization of horse manure through catalytic supercritical water gasification.

PubMed

Nanda, Sonil; Dalai, Ajay K; Gökalp, Iskender; Kozinski, Janusz A

2016-06-01

The organic wastes such as lignocellulosic biomass, municipal solid waste, sewage sludge and livestock manure have attracted attention as alternative sources of energy. Cattle manure, a waste generated in surplus amounts from the feedlot, has always been a chief environmental concern. This study is focused on identifying the candidacy of horse manure as a next generation feedstock for biofuel production through supercritical water gasification. The horse manure was gasified in supercritical water to examine the effects of temperature (400-600°C), biomass-to-water ratio (1:5 and 1:10) and reaction time (15-45min) at a pressure range of 23-25MPa. The horse manure and resulting biochar were characterized through carbon-hydrogen-nitrogen-sulfur (CHNS), inductively coupled plasma-mass spectrometry (ICP-MS), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy and scanning electron microscopy (SEM). The effects of alkali catalysts such as NaOH, Na2CO3 and K2CO3 at variable concentrations (1-2wt%) were investigated to maximize the hydrogen yields. Supercritical water gasification of horse manure with 2wt% Na2CO3 at 600°C and 1:10 biomass-to-water ratio for 45min revealed maximum hydrogen yields (5.31mmol/g), total gas yields (20.8mmol/g) with greater carbon conversion efficiency (43.1%) and enhanced lower heating value of gas products (2920kJ/Nm(3)). The manure-derived biochars generated at temperatures higher than 500°C also demonstrated higher thermal stability (weight loss <34%) and larger carbon content (>70wt%) suggesting their application in enhancing soil fertility and carbon sequestration. The results propose that supercritical water gasification could be a proficient remediation technology for horse manure to generate hydrogen-rich gas products. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mathematical modeling of control system for the experimental steam generator

NASA Astrophysics Data System (ADS)

Podlasek, Szymon; Lalik, Krzysztof; Filipowicz, Mariusz; Sornek, Krzysztof; Kupski, Robert; Raś, Anita

2016-03-01

A steam generator is an essential unit of each cogeneration system using steam machines. Currently one of the cheapest ways of the steam generation can be application of old steam generators came from army surplus store. They have relatively simple construction and in case of not so exploited units - quite good general conditions, and functionality of mechanical components. By contrast, electrical components and control systems (mostly based on relay automatics) are definitely obsolete. It is not possible to use such units with cooperation of steam bus or with steam engines. In particular, there is no possibility for automatically adjustment of the pressure and the temperature of the generated steam supplying steam engines. Such adjustment is necessary in case of variation of a generator load. The paper is devoted to description of improvement of an exemplary unit together with construction of the measurement-control system based on a PLC. The aim was to enable for communication between the steam generator and controllers of the steam bus and steam engines in order to construction of a complete, fully autonomic and maintenance-free microcogeneration system.

SMUVS: Spitzer Matching survey of the UltraVISTA ultra-deep Stripes

NASA Astrophysics Data System (ADS)

Caputi, Karina; Ashby, Matthew; Fazio, Giovanni; Huang, Jiasheng; Dunlop, James; Franx, Marijn; Le Fevre, Olivier; Fynbo, Johan; McCracken, Henry; Milvang-Jensen, Bo; Muzzin, Adam; Ilbert, Olivier; Somerville, Rachel; Wechsler, Risa; Behroozi, Peter; Lu, Yu

2014-12-01

We request 2026.5 hours to homogenize the matching ultra-deep IRAC data of the UltraVISTA ultra-deep stripes, producing a final area of ~0.6 square degrees with the deepest near- and mid-IR coverage existing in any such large area of the sky (H, Ks, [3.6], [4.5] ~ 25.3-26.1 AB mag; 5 sigma). The UltraVISTA ultra-deep stripes are contained within the larger COSMOS field, which has a rich collection of multi-wavelength, ancillary data, making it ideal to study different aspects of galaxy evolution with high statistical significance and excellent redshift accuracy. The UltraVISTA ultra-deep stripes are the region of the COSMOS field where these studies can be pushed to the highest redshifts, but securely identifying high-z galaxies, and determining their stellar masses, will only be possible if ultra-deep mid-IR data are available. Our IRAC observations will allow us to: 1) extend the galaxy stellar mass function at redshifts z=3 to z=5 to the intermediate mass regime (M~5x10^9-10^10 Msun), which is critical to constrain galaxy formation models; 2) gain a factor of six in the area where it is possible to effectively search for z>=6 galaxies and study their properties; 3) measure, for the first time, the large-scale structure traced by an unbiased galaxy sample at z=5 to z=7, and make the link to their host dark matter haloes. This cannot be done in any other field of the sky, as the UltraVISTA ultra-deep stripes form a quasi-contiguous, regular-shape field, which has a unique combination of large area and photometric depth. 4) provide a unique resource for the selection of secure z>5 targets for JWST and ALMA follow up. Our observations will have an enormous legacy value which amply justifies this new observing-time investment in the COSMOS field. Spitzer cannot miss this unique opportunity to open up a large 0.6 square-degree window to the early Universe.

Pulsed Laser Ablation Synthesis of Diamond Molecules in Supercritical Fluids

NASA Astrophysics Data System (ADS)

Nakahara, Sho; Stauss, Sven; Miyazoe, Hiroyuki; Shizuno, Tomoki; Suzuki, Minoru; Kataoka, Hiroshi; Sasaki, Takehiko; Terashima, Kazuo

2010-09-01

Nanocarbon materials have been synthesized by pulsed laser ablation (532 nm; 52 J/cm2; 7 ns; 10 Hz) of highly oriented pyrolytic graphite in adamantane-dissolved supercritical xenon at a temperature T = 290.2 K and pressure p = 5.86 MPa. Micro-Raman spectroscopy of the products revealed the presence of hydrocarbons possessing sp3 hybridized bonds also found in diamond structures. The synthesis of diamantane was confirmed by gas chromatography-mass spectrometry. The same measurements also indicate the possible synthesis of other diamondoids up to octamantane. Thus, laser ablation in supercritical fluids is proposed as one practical method of synthesizing diamondoids.

Polyester Fabric's Fluorescent Dyeing in Supercritical Carbon Dioxide and its Fluorescence Imaging.

PubMed

Xiong, Xiaoqing; Xu, Yanyan; Zheng, Laijiu; Yan, Jun; Zhao, Hongjuan; Zhang, Juan; Sun, Yanfeng

2017-03-01

As one of the most important coumarin-like dyes, disperse fluorescent Yellow 82 exhibits exceptionally large two-photon effects. Here, it was firstly introduced into the supercritical CO 2 dyeing polyester fabrics in this work. Results of the present work showed that the dyeing parameters such as the dyeing time, pressure and temperature had remarkable influences on the color strength of fabrics. The optimized dyeing condition in supercritical CO 2 dyeing has been proposed that the dyeing time was 60 min; the pressure was 25 MPa and the temperature was 120 °C. As a result, acceptable products were obtained with the wash and rub fastness rating at 5 or 4-5. The polyester fabrics dyed with fluorescent dyes can be satisfied for the requirement of manufacturing warning clothing. Importantly, the confocal microscopy imaging technology was successfully introduced into textile fields to observe the distribution and fluorescence intensity of disperse fluorescent Yellow 82 on polyester fabrics. As far as we know, this is the first report about supercritical CO 2 dyeing polyester fabrics based on disperse fluorescent dyes. It will be very helpful for the further design of new fluorescent functional dyes suitable for supercritical CO 2 dyeing technique.

Apparatus and methods for supplying auxiliary steam in a combined cycle system

DOEpatents

Gorman, William G.; Carberg, William George; Jones, Charles Michael

2002-01-01

To provide auxiliary steam, a low pressure valve is opened in a combined cycle system to divert low pressure steam from the heat recovery steam generator to a header for supplying steam to a second combined cycle's steam turbine seals, sparging devices and cooling steam for the steam turbine if the steam turbine and gas turbine lie on a common shaft with the generator. Cooling steam is supplied the gas turbine in the combined cycle system from the high pressure steam turbine. Spent gas turbine cooling steam may augment the low pressure steam supplied to the header by opening a high pressure valve whereby high and low pressure steam flows are combined. An attemperator is used to reduce the temperature of the combined steam in response to auxiliary steam flows above a predetermined flow and a steam header temperature above a predetermined temperature. The auxiliary steam may be used to start additional combined cycle units or to provide a host unit with steam turbine cooling and sealing steam during full-speed no-load operation after a load rejection.

Improved Supercritical-Solvent Extraction of Coal

NASA Technical Reports Server (NTRS)

Compton, L.

1982-01-01

Raw coal upgraded by supercritical-solvent extraction system that uses two materials instead of one. System achieved extraction yields of 20 to 49 weight percent. Single-solvent yields are about 25 weight percent. Experimental results show extraction yields may be timedependent. Observed decreases in weight of coal agreed well with increases in ash content of residue.

Novel micronisation β-carotene using rapid expansion supercritical solution with co-solvent

NASA Astrophysics Data System (ADS)

Kien, Le Anh

2017-09-01

Rapid expansion of supercritical solution (RESS) is the most common approach of pharmaceutical pacticle forming methods using supercritical fluids. The RESS method is a technology producing a small solid product with a very narrow particle size distribution, organic solvent-free particles. This process is also simple and easy to control the operating parameters in comparision with other ways based on supercritical techniques. In this study, β-carotene, a strongly colored red-orange pigment abundant in plants and fruits, has been forming by RESS. In addition, the size and morphology effect of four different RESS parameters including co-solvent, extraction temperature, and extraction pressure and expansion nozzle temperature has surveyed. The particle size distribution has been determined by using laser diffraction experiment. SEM has conducted to analyze the surface structure, DSC and FTIR for thermal and chemical structure analysis.

49 CFR 230.65 - Steam blocking view of engine crew.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Steam blocking view of engine crew. 230.65 Section... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Steam Leaks § 230.65 Steam blocking view of engine crew. The steam locomotive owner and/or...

Imitative modeling automatic system Control of steam pressure in the main steam collector with the influence on the main Servomotor steam turbine

NASA Astrophysics Data System (ADS)

Andriushin, A. V.; Zverkov, V. P.; Kuzishchin, V. F.; Ryzhkov, O. S.; Sabanin, V. R.

2017-11-01

The research and setting results of steam pressure in the main steam collector “Do itself” automatic control system (ACS) with high-speed feedback on steam pressure in the turbine regulating stage are presented. The ACS setup is performed on the simulation model of the controlled object developed for this purpose with load-dependent static and dynamic characteristics and a non-linear control algorithm with pulse control of the turbine main servomotor. A method for tuning nonlinear ACS with a numerical algorithm for multiparametric optimization and a procedure for separate dynamic adjustment of control devices in a two-loop ACS are proposed and implemented. It is shown that the nonlinear ACS adjusted with the proposed method with the regulators constant parameters ensures reliable and high-quality operation without the occurrence of oscillations in the transient processes the operating range of the turbine loads.

BWR Steam Dryer Alternating Stress Assessment Procedures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morante, R. J.; Hambric, S. A.; Ziada, S.

2016-12-01

This report presents an overview of Boiling Water Reactor (BWR) steam dryer design; the fatigue cracking failures that occurred at the Quad Cities (QC) plants and their root causes; a history of BWR Extended Power Uprates (EPUs) in the USA; and a discussion of steam dryer modifications/replacements, alternating stress mechanisms on steam dryers, and structural integrity evaluations (static and alternating stress).

Supercritical Water Oxidation Total Organic Carbon (TOC) Analysis

EPA Pesticide Factsheets

The work presented here is the evaluation of the modified wet‐oxidation method described as Supercritical Water Oxidation (SCWO) for the analysis of total organic carbon (TOC) in very difficult oil/gas produced water sample matrices.

Supercritical fluid extraction and processing of foods

USDA-ARS?s Scientific Manuscript database

Consumers are aware of the processing techniques used to manufacture food and health supplements and are concerned about the impact of those processes on their health and the environment. Processes that use supercritical fluids as an alternative to solvents that are used to extract nutrients and bio...

NUCLEAR FLASH TYPE STEAM GENERATOR

DOEpatents

Johns, F.L.; Gronemeyer, E.C.; Dusbabek, M.R.

1962-09-01

A nuclear steam generating apparatus is designed so that steam may be generated from water heated directly by the nuclear heat source. The apparatus comprises a pair of pressure vessels mounted one within the other, the inner vessel containing a nuclear reactor heat source in the lower portion thereof to which water is pumped. A series of small ports are disposed in the upper portion of the inner vessel for jetting heated water under pressure outwardly into the atmosphere within the interior of the outer vessel, at which time part of the jetted water flashes into steam. The invention eliminates the necessity of any intermediate heat transfer medium and components ordinarily required for handling that medium. (AEC)

On-line supercritical fluid extraction-supercritical fluid chromatography-mass spectrometry of polycyclic aromatic hydrocarbons in soil.

PubMed

Wicker, A Paige; Carlton, Doug D; Tanaka, Kenichiro; Nishimura, Masayuki; Chen, Vivian; Ogura, Tairo; Hedgepeth, William; Schug, Kevin A

2018-06-01

On-line supercritical fluid extraction - supercritical fluid chromatography - mass spectrometry (SFE-SFC-MS) has been applied for the determination of polycyclic aromatic hydrocarbons (PAHs) in soil. The purpose of this study was to develop and validate the first on-line SFE-SFC-MS method for the quantification of PAHs in various types of soil. By coupling the sample extraction on-line with chromatography and detection, sample preparation is minimized, diminishing sample loss and contamination, and significantly decreasing the required extraction time. Parameters for on-line extraction coupled to chromatographic analysis were optimized. The method was validated for concentrations of 10-1500 ng of PAHs per gram of soil in Certified Reference Material (CRM) sediment, clay, and sand with R 2  ≥ 0.99. Limits of detection (LOD) were found in the range of 0.001-5 ng/g, and limits of quantification (LOQ) in the range of 5-15 ng/g. The method developed in this study can be effectively applied to the study of PAHs in the environment, and may lay the foundation for further applications of on-line SFE-SFC-MS. Copyright © 2018 Elsevier B.V. All rights reserved.

Cogeneration steam turbines from Siemens: New solutions

NASA Astrophysics Data System (ADS)

Kasilov, V. F.; Kholodkov, S. V.

2017-03-01

The Enhanced Platform system intended for the design and manufacture of Siemens AG turbines is presented. It combines organizational and production measures allowing the production of various types of steam-turbine units with a power of up to 250 MWel from standard components. The Enhanced Platform designs feature higher efficiency, improved reliability, better flexibility, longer overhaul intervals, and lower production costs. The design features of SST-700 and SST-900 steam turbines are outlined. The SST-700 turbine is used in backpressure steam-turbine units (STU) or as a high-pressure cylinder in a two-cylinder condensing turbine with steam reheat. The design of an SST-700 single-cylinder turbine with a casing without horizontal split featuring better flexibility of the turbine unit is presented. An SST-900 turbine can be used as a combined IP and LP cylinder (IPLPC) in steam-turbine or combined-cycle power units with steam reheat. The arrangements of a turbine unit based on a combination of SST-700 and SST-900 turbines or SST-500 and SST-800 turbines are presented. Examples of this combination include, respectively, PGU-410 combinedcycle units (CCU) with a condensing turbine and PGU-420 CCUs with a cogeneration turbine. The main equipment items of a PGU-410 CCU comprise an SGT5-4000F gas-turbine unit (GTU) and STU consisting of SST-700 and SST-900RH steam turbines. The steam-turbine section of a PGU-420 cogeneration power unit has a single-shaft turbine unit with two SST-800 turbines and one SST-500 turbine giving a power output of N el. STU = 150 MW under condensing conditions.

Modern supercritical fluid technology for food applications.

PubMed

King, Jerry W

2014-01-01

This review provides an update on the use of supercritical fluid (SCF) technology as applied to food-based materials. It advocates the use of the solubility parameter theory (SPT) for rationalizing the results obtained when employing sub- and supercritical media to food and nutrient-bearing materials and for optimizing processing conditions. Total extraction and fractionation of foodstuffs employing SCFs are compared and are illustrated by using multiple fluids and unit processes to obtain the desired food product. Some of the additional prophylactic benefits of using carbon dioxide as the processing fluid are explained and illustrated with multiple examples of commercial products produced using SCF media. I emphasize the role of SCF technology in the context of environmentally benign and sustainable processing, as well as its integration into an overall biorefinery concept. Conclusions are drawn in terms of current trends in the field and future research that is needed to secure new applications of the SCF platform as applied in food science and technology.

Isolation of essential oil from different plants and herbs by supercritical fluid extraction.

PubMed

Fornari, Tiziana; Vicente, Gonzalo; Vázquez, Erika; García-Risco, Mónica R; Reglero, Guillermo

2012-08-10

Supercritical fluid extraction (SFE) is an innovative, clean and environmental friendly technology with particular interest for the extraction of essential oil from plants and herbs. Supercritical CO(2) is selective, there is no associated waste treatment of a toxic solvent, and extraction times are moderate. Further, supercritical extracts were often recognized of superior quality when compared with those produced by hydro-distillation or liquid-solid extraction. This review provides a comprehensive and updated discussion of the developments and applications of SFE in the isolation of essential oils from plant matrices. SFE is normally performed with pure CO(2) or using a cosolvent; fractionation of the extract is commonly accomplished in order to isolate the volatile oil compounds from other co-extracted substances. In this review the effect of pressure, temperature and cosolvent on the extraction and fractionation procedure is discussed. Additionally, a comparison of the extraction yield and composition of the essential oil of several plants and herbs from Lamiaceae family, namely oregano, sage, thyme, rosemary, basil, marjoram and marigold, which were produced in our supercritical pilot-plant device, is presented and discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

Experiences with industrial solar process steam generation in Jordan

NASA Astrophysics Data System (ADS)

Krüger, Dirk; Berger, Michael; Mokhtar, Marwan; Willwerth, Lisa; Zahler, Christian; Al-Najami, Mahmoud; Hennecke, Klaus

2017-06-01

At the Jordanian pharmaceuticals manufacturing company RAM Pharma a solar process heat supply has been constructed by Industrial Solar GmbH in March 2015 and operated since then (Figure 1). The collector field consists of 394 m² of linear Fresnel collectors supplying saturated steam to the steam network at RAM Pharma at about 6 bar gauge. In the frame of the SolSteam project funded by the German Federal Ministry for Economic Affairs and Energy (BMWi) the installation has been modified introducing an alternative way to separate water and steam by a cyclone. This paper describes the results of experiments with the cyclone and compares the operation with a steam drum. The steam production of the solar plant as well as the fuel demand of the steam boiler are continuously monitored and results are presented in this paper.

Estimation of lifespan and economy parameters of steam-turbine power units in thermal power plants using varying regimes

NASA Astrophysics Data System (ADS)

Aminov, R. Z.; Shkret, A. F.; Garievskii, M. V.

2016-08-01

The use of potent power units in thermal and nuclear power plants in order to regulate the loads results in intense wear of power generating equipment and reduction in cost efficiency of their operation. We review the methodology of a quantitative assessment of the lifespan and wear of steam-turbine power units and estimate the effect of various operation regimes upon their efficiency. To assess the power units' equipment wear, we suggest using the concept of a turbine's equivalent lifespan. We give calculation formulae and an example of calculation of the lifespan of a steam-turbine power unit for supercritical parameters of steam for different options of its loading. The equivalent lifespan exceeds the turbine's assigned lifespan only provided daily shutdown of the power unit during the night off-peak time. We obtained the engineering and economical indices of the power unit operation for different loading regulation options in daily and weekly diagrams. We proved the change in the prime cost of electric power depending on the operation regimes and annual daily number of unloading (non-use) of the power unit's installed capacity. According to the calculation results, the prime cost of electric power for the assumed initial data varies from 11.3 cents/(kW h) in the basic regime of power unit operation (with an equivalent operation time of 166700 hours) to 15.5 cents/(kW h) in the regime with night and holiday shutdowns. The reduction of using the installed capacity of power unit at varying regimes from 3.5 to 11.9 hours per day can increase the prime cost of energy from 4.2 to 37.4%. Furthermore, repair and maintenance costs grow by 4.5% and by 3 times, respectively, in comparison with the basic regime. These results indicate the need to create special maneuverable equipment for working in the varying section of the electric load diagram.

Supplementary steam - A viable hydrogen power generation concept

NASA Technical Reports Server (NTRS)

Wright, D. E.; Lee, J. C.

1979-01-01

Technical and economic aspects of a supplementary steam generation for peaking power applications are discussed. Preliminary designs of the hydrogen/oxygen combustors to be used for such applications are described. The integration of the hydrogen/oxygen steam-generating equipment into a typical coal-fired steam station is studied. The basic steam generation system was designed as a 20 MW supplementary system to be added to the existing 160 MW system. An analysis of the operating and design requirements of the supplementary system is conducted. Estimates were made for additional steam and fuel supply lines and for additional control required to operate the combustors and to integrate the combustor system into the facility.

Techniques, applications and future prospects of diamond anvil cells for studying supercritical water systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, Jr., R.L.; Fang, Z.; Tohoku)

In this review, diamond anvil type cells (DACs) are reviewed as a method for studying supercritical water systems. The hydrothermal DAC provides easy and safe experimental access to high pressure (30-3000 MPa) and high temperature (400-800 C) regions and the device allows exploration of supercritical systems at high density (400-1200 kg/m{sup 3}), which is usually difficult or costly with batch or flow systems. In the first part of this review, characteristics of DACs regarding anvil type, DAC type, anvil alignment, heating, analytical methods, pressure and temperature determination, gasket, loading, physical size are discussed with emphasis on DACs that can bemore » used to generate conditions of interest for understanding supercritical water systems. In the second part of this review, applications and key findings of studies on supercritical water systems from geology, chemical, biomass, energy, environmental, polymer, and materials related fields are discussed. Some of the key findings determined with DAC are related to the dissolution or existence of phases at conditions of high temperature and high pressure, however, DAC has been used in many quantitative studies to determine fundamental properties such as speeds of sound, phase behavior, solubilities, partition coefficients and viscosities. Future prospects for DAC as a method for exploring supercritical water systems include combination of DAC with transmission electron microscopy (TEM) for studying nanostructures, use of high-speed streak cameras to study high-speed reactions, combustions, and energetic materials, use of time-dependent loads to study kinetics, precipitation and crystallization phenomena, the use of DAC with synchrotron radiation to follow reaction and material processes in situ, and the many modifications that can be made to DAC anvils and rapid heating methods such as lasers and masers used in conjunction with in situ techniques. The DAC is a highly versatile instrument and should find

Swirl-Stabilized Injector Flow and Combustion Dynamics for Liquid Propellants at Supercritical Conditions

DTIC Science & Technology

2007-02-08

was employed to study the vapor cavitation during liquid carbon dioxide expansion through a sharp-orifice nozzle. Numerical experiments demonstrated...Combustion Dynamics for 6b. GRANT NUMBER Liquid Propellants at Supercritical Conditions FA9550-04-1-0014 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT...fundamental knowledge of supercritical combustion of liquid propellants under conditions representative of contemporary rocket engines. Both shear and

Heat transfer during condensation of steam from steam-gas mixtures in the passive safety systems of nuclear power plants

NASA Astrophysics Data System (ADS)

Portnova, N. M.; Smirnov, Yu B.

2017-11-01

A theoretical model for calculation of heat transfer during condensation of multicomponent vapor-gas mixtures on vertical surfaces, based on film theory and heat and mass transfer analogy is proposed. Calculations were performed for the conditions implemented in experimental studies of heat transfer during condensation of steam-gas mixtures in the passive safety systems of PWR-type reactors of different designs. Calculated values of heat transfer coefficients for condensation of steam-air, steam-air-helium and steam-air-hydrogen mixtures at pressures of 0.2 to 0.6 MPa and of steam-nitrogen mixture at the pressures of 0.4 to 2.6 MPa were obtained. The composition of mixtures and vapor-to-surface temperature difference were varied within wide limits. Tube length ranged from 0.65 to 9.79m. The condensation of all steam-gas mixtures took place in a laminar-wave flow mode of condensate film and turbulent free convection in the diffusion boundary layer. The heat transfer coefficients obtained by calculation using the proposed model are in good agreement with the considered experimental data for both the binary and ternary mixtures.

Applications of supercritical fluid extraction (SFE) of palm oil and oil from natural sources.

PubMed

Akanda, Mohammed Jahurul Haque; Sarker, Mohammed Zaidul Islam; Ferdosh, Sahena; Manap, Mohd Yazid Abdul; Ab Rahman, Nik Norulaini Nik; Ab Kadir, Mohd Omar

2012-02-10

Supercritical fluid extraction (SFE), which has received much interest in its use and further development for industrial applications, is a method that offers some advantages over conventional methods, especially for the palm oil industry. SC-CO₂ refers to supercritical fluid extraction (SFE) that uses carbon dioxide (CO₂) as a solvent which is a nontoxic, inexpensive, nonflammable, and nonpolluting supercritical fluid solvent for the extraction of natural products. Almost 100% oil can be extracted and it is regarded as safe, with organic solvent-free extracts having superior organoleptic profiles. The palm oil industry is one of the major industries in Malaysia that provides a major contribution to the national income. Malaysia is the second largest palm oil and palm kernel oil producer in the World. This paper reviews advances in applications of supercritical carbon dioxide (SC-CO₂) extraction of oils from natural sources, in particular palm oil, minor constituents in palm oil, producing fractionated, refined, bleached, and deodorized palm oil, palm kernel oil and purified fatty acid fractions commendable for downstream uses as in toiletries and confectionaries.

Supercritical water oxidation for wastewater treatment Preliminary study of urea destruction

NASA Technical Reports Server (NTRS)

Timberlake, S. H.; Hong, G. T.; Simson, M.; Modell, M.

1982-01-01

Supercritical water oxidation is being investigated as a method of treating spacecraft wastewater for recycle. In this process, oxidation is conducted in an aqueous phase maintained above the critical temperature (374 C) and pressure (215 bar) of water. Organic materials are oxidized with efficiencies greater than 99.99 percent in residence times of less than 1 minute. This paper presents preliminary results for urea destruction. Above 650 C, urea can be completely broken down to nitrogen gas, carbon dioxide and water by supercritical water oxidation, without the use of a specific catalyst.

Thermoelastic steam turbine rotor control based on neural network

NASA Astrophysics Data System (ADS)

Rzadkowski, Romuald; Dominiczak, Krzysztof; Radulski, Wojciech; Szczepanik, R.

2015-12-01

Considered here are Nonlinear Auto-Regressive neural networks with eXogenous inputs (NARX) as a mathematical model of a steam turbine rotor for controlling steam turbine stress on-line. In order to obtain neural networks that locate critical stress and temperature points in the steam turbine during transient states, an FE rotor model was built. This model was used to train the neural networks on the basis of steam turbine transient operating data. The training included nonlinearity related to steam turbine expansion, heat exchange and rotor material properties during transients. Simultaneous neural networks are algorithms which can be implemented on PLC controllers. This allows for the application neural networks to control steam turbine stress in industrial power plants.

Gases in steam from Cerro Prieto geothermal wells with a discussion of steam/gas ratio measurements

USGS Publications Warehouse

Nehring, N.L.; Fausto, L.J.J.

1979-01-01

As part of a joint USGS-CFE geochemical study of Cerro Prieto, steam samples were collected for gas analyses in April, 1977. Analyses of the major gas components of the steam were made by wet chemistry (for H2O,CO2,H2S and NH3) and by gas chromatography (He,H2,Ar,O2,N2 and hydrocarbons). The hydrocarbon gases in Cerro Prieto steam closely resemble hydrocarbons in steam from Larderello, Italy and The Geysers, California which, although they are vapor-dominated rather than hot-water geothermal systems, also have sedimentary aquifer rocks. These sedimentary geothermal hydrocarbons are characterized by the presence of branched C4-6 compounds and a lack of unsaturated compounds other than benzene. Relatively large amounts of benzene may be characteristic of high-temperature geothermal systems. All hydrocarbons in these gases other than methane most probably originate from the thermal metamorphosis of organic matter contained in the sediments. ?? 1979.

Phytochemical composition of fractions isolated from ten Salvia species by supercritical carbon dioxide and pressurized liquid extraction methods.

PubMed

Šulniūtė, Vaida; Pukalskas, Audrius; Venskutonis, Petras Rimantas

2017-06-01

Ten Salvia species, S. amplexicaulis, S. austriaca, S. forsskaolii S. glutinosa, S. nemorosa, S. officinalis, S. pratensis, S. sclarea, S. stepposa and S. verticillata were fractionated using supercritical carbon dioxide and pressurized liquid (ethanol and water) extractions. Fifteen phytochemicals were identified using commercial standards (some other compounds were identified tentatively), 11 of them were quantified by ultra high pressure chromatography (UPLC) with quadruple and time-of-flight mass spectrometry (Q/TOF, TQ-S). Lipophilic CO 2 extracts were rich in tocopherols (2.36-10.07mg/g), while rosmarinic acid was dominating compound (up to 30mg/g) in ethanolic extracts. Apigenin-7-O-β-d-glucuronide, caffeic and carnosic acids were quantitatively important phytochemicals in the majority other Salvia spp. Antioxidatively active constituents were determined by using on-line high-performance liquid chromatography (HPLC) analysis combined with 2,2'-diphenyl-1-picrylhydrazyl (DPPH) assay (HPLC-DPPH). Development of high pressure isolation process and comprehensive characterisation of phytochemicals in Salvia spp. may serve for their wider applications in functional foods and nutraceuticals. Copyright © 2016 Elsevier Ltd. All rights reserved.

Analysis of Supercritical-Extracted Chelated Metal Ions From Mixed Organic-Inorganic Samples

NASA Technical Reports Server (NTRS)

Sinha, Mahadeva P. (Inventor)

1996-01-01

Organic and inorganic contaminants of an environmental sample are analyzed by the same GC-MS instrument by adding an oxidizing agent to the sample to oxidize metal or metal compounds to form metal ions. The metal ions are converted to chelate complexes and the chelate complexes are extracted into a supercritical fluid such as CO2. The metal chelate extract after flowing through a restrictor tube is directly injected into the ionization chamber of a mass spectrometer, preferably containing a refractory metal filament such as rhenium to fragment the complex to release metal ions which are detected. This provides a fast, economical method for the analysis of metal contaminants in a sample and can be automated. An organic extract of the sample in conventional or supercritical fluid solvents can be detected in the same mass spectrometer, preferably after separation in a supercritical fluid chromatograph.

MALEIC ANHYDRIDE HYDROGENATION OF PD/AL2O3 CATALYST UNDER SUPERCRITICAL CO2 MEDIUM

EPA Science Inventory

Hydrogenation of maleic anhydride (MA) to either y-butyrolactone of succinic anhydride over simple Pd/Al2O3 impregnated catalyst in supercritical CO2 medium has been studied at different temperatures and pressures. A comparison of the supercritical CO2 medium reaction with the c...

Solute Nucleation and Growth in Supercritical Fluid Mixtures

NASA Technical Reports Server (NTRS)

Smedley, Gregory T.; Wilemski, Gerald; Rawlins, W. Terry; Joshi, Prakash; Oakes, David B.; Durgin, William W.

1996-01-01

This research effort is directed toward two primary scientific objectives: (1) to determine the gravitational effect on the measurement of nucleation and growth rates near a critical point and (2) to investigate the nucleation process in supercritical fluids to aid in the evaluation and development of existing theoretical models and practical applications. A nucleation pulse method will be employed for this investigation using a rapid expansion to a supersaturated state that is maintained for approximately 1 ms followed by a rapid recompression to a less supersaturated state that effectively terminates nucleation while permitting growth to continue. Nucleation, which occurs during the initial supersaturated state, is decoupled from growth by producing rapid pressure changes. Thermodynamic analysis, condensation modeling, apparatus design, and optical diagnostic design necessary for the initiation of a theoretical and experimental investigation of naphthalene nucleation from supercritical CO2 have been completed.

Spontaneous Ignition of Hydrothermal Flames in Supercritical Ethanol Water Solutions

NASA Technical Reports Server (NTRS)

Hicks, Michael C.; Hegde, Uday G.; Kojima, Jun J.

2017-01-01

Results are reported from recent tests where hydrothermal flames spontaneously ignited in a Supercritical Water Oxidation (SCWO) Test Cell. Hydrothermal flames are generally categorized as flames that occur when appropriate concentrations of fuel and oxidizer are present in supercritical water (SCW); i.e., water at conditions above its critical point (218 atm and 374 C). A co-flow injector was used to inject fuel, comprising an aqueous solution of 30-vol to 50-vol ethanol, and air into a reactor held at constant pressure and filled with supercritical water at approximately 240 atm and 425 C. Hydrothermal flames auto-ignited and quickly stabilized as either laminar or turbulent diffusion flames, depending on the injection velocities and test cell conditions. Two orthogonal views, one of which provided a backlit shadowgraphic image, provided visual observations. Optical emission measurements of the steady state flame were made over a spectral range spanning the ultraviolet (UV) to the near infrared (NIR) using a high-resolution, high-dynamic-range spectrometer. Depending on the fuel air flow ratios varying degrees of sooting were observed and are qualitatively compared using light absorption comparisons from backlit images.

Antioxidant effects of supercritical fluid garlic extracts in sunflower oil.

PubMed

Bravi, Elisabetta; Perretti, Giuseppe; Falconi, Caterina; Marconi, Ombretta; Fantozzi, Paolo

2017-01-01

Lipid oxidation causes changes in quality attributes of vegetable oils. Synthetic antioxidants have been used to preserve oils; however, there is interest in replacing them with natural ones. Garlic and its thiosulfinate compound allicin are known for their antioxidant activities. This study assesses a novel formulation, the supercritical fluid extract of garlic, on sunflower oil oxidation during an accelerated shelf-life test. Three quality parameters (free acidity, peroxide values, and p-anisidine values) were evaluated in each of the six oil samples. The samples included sunflower oil alone, sunflower oil supplemented with BHT, the undiluted supercritical fluid extract of garlic, and sunflower oils supplemented with three levels of garlic extract. The oils were also investigated for their antioxidant properties using the DPPH and the FRAP assays. The results were compared with the effect of the synthetic BHT. Our results underlined that the highest level of garlic extract may be superior, or at least comparable, with BHT in preserving sunflower oil. The oxidative degradation of oily samples can be limited by using supercritical fluid extract of garlic as it is a safe and an effective natural antioxidant formulation. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

[Defective function of bioindicators for steam sterilization].

PubMed

Botzenhart, K; Merkt-Kinzler, M

1990-05-01

It can be shown, that under certain conditions commercially available indicators with Bacillus stearothermophilus and packages of native spores from soil prepared according to DIN 58 946/4 react differently to treatment in a lab-type steam sterilizer. The differences were most evident when incomplete evacuation of air had to be supposed. These results lead to the conclusion that some bioindicators are not able to show the inefficient function of steam sterilizers caused by local residuals of air. This may be caused by the properties of the selected strain, by the conditions of growth and preparation of the spores and by the culture medium used after exposition. The results of our experiments as well as the resistance of mesophilic spore forming bacilli against dry heat described by other authors make it necessary to test the resistance of bioindicators for steam sterilization not only against steam according to DIN 58946/4 but also against dry heat or mixtures of steam and air.

Brush Seals for Improved Steam Turbine Performance

NASA Technical Reports Server (NTRS)

Turnquist, Norman; Chupp, Ray; Baily, Fred; Burnett, Mark; Rivas, Flor; Bowsher, Aaron; Crudgington, Peter

2006-01-01

GE Energy has retrofitted brush seals into more than 19 operating steam turbines. Brush seals offer superior leakage control compared to labyrinth seals, owing to their compliant nature and ability to maintain very tight clearances to the rotating shaft. Seal designs have been established for steam turbines ranging in size from 12 MW to over 1200 MW, including fossil, nuclear, combined-cycle and industrial applications. Steam turbines present unique design challenges that must be addressed to ensure that the potential performance benefits of brush seals are realized. Brush seals can have important effects on the overall turbine system that must be taken into account to assure reliable operation. Subscale rig tests are instrumental to understanding seal behavior under simulated steam-turbine operating conditions, prior to installing brush seals in the field. This presentation discusses the technical challenges of designing brush seals for steam turbines; subscale testing; performance benefits of brush seals; overall system effects; and field applications.

NIST/ASME Steam Properties Database

National Institute of Standards and Technology Data Gateway

SRD 10 NIST/ASME Steam Properties Database (PC database for purchase)   Based upon the International Association for the Properties of Water and Steam (IAPWS) 1995 formulation for the thermodynamic properties of water and the most recent IAPWS formulations for transport and other properties, this updated version provides water properties over a wide range of conditions according to the accepted international standards.

K-65-12.8 condensing steam turbine

NASA Astrophysics Data System (ADS)

Valamin, A. E.; Kultyshev, A. Yu.; Gol'dberg, A. A.; Sakhnin, Yu. A.; Bilan, V. N.; Stepanov, M. Yu.; Polyaeva, E. N.; Shekhter, M. V.; Shibaev, T. L.

2016-11-01

A new condensing steam turbine K-65-12.8 is considered, which is the continuation of the development of the steam turbine family of 50-70 MW and the fresh steam pressure of 12.8 MPa, such as twocylinder T-50-12.8 and T-60/65-12.8 turbines. The turbine was developed using the modular design. The design and the main distinctive features of the turbine are described, such as a single two-housing cylinder with the steam flow loop; the extraction from the blading section for the regeneration, the inner needs, and heating; and the unification of some assemblies of serial turbines with shorter time of manufacture. The turbine uses the throttling steam distribution; steam from a boiler is supplied to a turbine through a separate valve block consisting of a central shut-off valve and two side control valves. The blading section of a turbine consists of 23 stages: the left flow contains ten stages installed in the inner housing and the right flow contains 13 stages with diaphragm placed in holders installed in the outer housing. The disks of the first 16 stages are forged together with a rotor, and the disks of the rest stages are mounted. Before the two last stages, the uncontrolled steam extraction is performed for the heating of a plant with the heat output of 38-75 GJ/h. Also, a turbine has five regenerative extraction points for feed water heating and the additional steam extraction to a collector for the inner needs with the consumption of up to 10 t/h. The feasibility parameters of a turbine plant are given. The main solutions for the heat flow diagram and the layout of a turbine plant are presented. The main principles and features of the microprocessor electro hydraulic control and protection system are formulated.

Production of D-lactic acid from sugarcane bagasse using steam-explosion

NASA Astrophysics Data System (ADS)

Sasaki, Chizuru; Okumura, Ryosuke; Asakawa, Ai; Asada, Chikako; Nakamura, Yoshitoshi

2012-03-01

This study investigated the production of D-lactic acid from unutilized sugarcane bagasse using steam explosion pretreatment. The optimal steam pressure for a steaming time of 5 min was determined. By enzymatic saccharification using Meicellase, the highest recovery of glucose from raw bagasse, 73.7%, was obtained at a steam pressure of 20 atm. For residue washed with water after steam explosion, the glucose recovery increased up to 94.9% at a steam pressure of 20 atm. These results showed that washing with water is effective in removing enzymatic reaction inhibitors. After steam pretreatment (steam pressure of 20 atm), D-lactic acid was produced by Lactobacillus delbrueckii NBRC 3534 from the enzymatic hydrolyzate of steam-exploded bagasse and washed residue. The conversion rate of D-lactic acid obtained from the initial glucose concentration was 66.6% for the hydrolyzate derived from steam-exploded bagasse and 90.0% for that derived from the washed residue after steam explosion. These results also demonstrated that the hydrolyzate of steam-exploded bagasse (without washing with water) contains fermentation inhibitors and washing with water can remove them.

[Chemical constituents from supercritical CO2 extraction of Schisandra chinensis].

PubMed

Zhu, Hong-yan; Lin, Hai-cheng; Wang, Guo-li; Zhang, Lian-xue

2014-11-01

To study the chemical constituents from the supercritical CO2 extraction of Schisandra chinensis. The compounds were separated and purified by conventional column chromatography and their structures were identified by spectroscopic methods. Nine compounds were isolated from the supercritical CO2 extraction of Schisandra chinensis, and their structures were identified as chrysophanol(1),schisandrin B(2), β-sitosterol(3), schisandrin C(4),schisandrol A(5), angeloylgomisin H(6), daucosterol(7) 1, 5-dimethyl citrate (8), and shikimic acid (9). Compounds 1, 8 and 9 are isolated from Schisandra chinensis for the first time,and compound 1 as an anthraquinone is isolated from this genus for the first time.

Supercritical fluid chromatography: a promising alternative to current bioanalytical techniques.

PubMed

Dispas, Amandine; Jambo, Hugues; André, Sébastien; Tyteca, Eva; Hubert, Philippe

2018-01-01

During the last years, chemistry was involved in the worldwide effort toward environmental problems leading to the birth of green chemistry. In this context, green analytical tools were developed as modern Supercritical Fluid Chromatography in the field of separative techniques. This chromatographic technique knew resurgence a few years ago, thanks to its high efficiency, fastness and robustness of new generation equipment. These advantages and its easy hyphenation to MS fulfill the requirements of bioanalysis regarding separation capacity and high throughput. In the present paper, the technical aspects focused on bioanalysis specifications will be detailed followed by a critical review of bioanalytical supercritical fluid chromatography methods published in the literature.

The wavenumbers of supercritical surface-tension-driven Benard convection

NASA Technical Reports Server (NTRS)

Koschmieder, E. L.; Switzer, D. W.

1992-01-01

The cell size or the wavenumbers of supercritical hexagonal convection cells in primarily surface-tension-driven convection on a uniformly heated plate has been studied experimentally in thermal equilibrium in thin layers of silicone oil of large aspect ratio. It has been found that the cell size decreases with increased temperature difference in the slightly supercritical range, and that the cell size is unique within the experimental error. It has also been observed that the cell size reaches a minimum and begins to increase at larger temperature differences. This reversal of the rate of change of the wavenumber with temperature difference is attributed to influences of buoyancy on the fluid motion. The consequences of buoyancy have been tested with three fluid layers of different depth.

Performance of the supercritical helium cooling loop for the JET divertor cryopump

DOE Office of Scientific and Technical Information (OSTI.GOV)

Obert, W.; Mayaux, C.; Barth, K.

1996-12-31

A supercritical helium cooling loop for the two JET divertor cryopumps has been tested, commissioned and is operational practically uninterrupted for over one year. Operation experience under a number of different boundary and transient conditions have been obtained. The flow of the supercritical helium (6 g/s, 2.7 bar) is driven by the main compressor of the JET helium refrigerator passing a heat exchanger where it is subcooled to 4.1 K before entering the two cryopumps which are an assembly of two 60 m long and 20 mm diameter corrugated stainless steel tubes. By using a dedicated cold ejector which ismore » driven by the main flow and where the expansion from 12 bar to 2.7 bar takes place increases the flow of supercritical helium up to {approximately}17 g/s. The steady state thermal load to the cooling loop of the cryopump is < 80 W but during transient conditions in particular due to nuclear heating in the active phase of JET considerably higher transient heat loads can be accepted by the loop. Details about the steady state and transient thermal conditions as well as the cooldown and warm up behavior of the loop and the interaction of the supercritical loop with the operation of other plant equipment will be discussed in the paper.« less

Fixation of compressive deformation in wood by pre-steaming

Treesearch

M. Inoue; N. Sekino; T. Morooka; R.M. Rowell; M. Norimoto

2008-01-01

Wood block specimens pre-steamed at 120-220 °C for 5-20 min were compressed in the radial direction. The recovery of set decreased with increasing pre-steaming temperature and time. The reduction of set recovery correlated with the amount of weight loss in steaming irrespective of pre-steaming temperature and time. The weight loss for the highest level of...

Model-based minimization algorithm of a supercritical helium loop consumption subject to operational constraints

NASA Astrophysics Data System (ADS)

Bonne, F.; Bonnay, P.; Girard, A.; Hoa, C.; Lacroix, B.; Le Coz, Q.; Nicollet, S.; Poncet, J.-M.; Zani, L.

2017-12-01

Supercritical helium loops at 4.2 K are the baseline cooling strategy of tokamaks superconducting magnets (JT-60SA, ITER, DEMO, etc.). This loops work with cryogenic circulators that force a supercritical helium flow through the superconducting magnets in order that the temperature stay below the working range all along their length. This paper shows that a supercritical helium loop associated with a saturated liquid helium bath can satisfy temperature constraints in different ways (playing on bath temperature and on the supercritical flow), but that only one is optimal from an energy point of view (every Watt consumed at 4.2 K consumes at least 220 W of electrical power). To find the optimal operational conditions, an algorithm capable of minimizing an objective function (energy consumption at 5 bar, 5 K) subject to constraints has been written. This algorithm works with a supercritical loop model realized with the Simcryogenics [2] library. This article describes the model used and the results of constrained optimization. It will be possible to see that the changes in operating point on the temperature of the magnet (e.g. in case of a change in the plasma configuration) involves large changes on the cryodistribution optimal operating point. Recommendations will be made to ensure that the energetic consumption is kept as low as possible despite the changing operating point. This work is partially supported by EUROfusion Consortium through the Euratom Research and Training Program 20142018 under Grant 633053.

Critical size of crystalline ZrO(2) nanoparticles synthesized in near- and supercritical water and supercritical isopropyl alcohol.

PubMed

Becker, Jacob; Hald, Peter; Bremholm, Martin; Pedersen, Jan S; Chevallier, Jacques; Iversen, Steen B; Iversen, Bo B

2008-05-01

Nanocrystalline ZrO(2) samples with narrow size distributions and mean particle sizes below 10 nm have been synthesized in a continuous flow reactor in near and supercritical water as well as supercritical isopropyl alcohol using a wide range of temperatures, pressures, concentrations and precursors. The samples were comprehensively characterized by powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS), and the influence of the synthesis parameters on the particle size, particle size distribution, shape, aggregation and crystallinity was studied. On the basis of the choice of synthesis parameters either monoclinic or tetragonal zirconia phases can be obtained. The results suggest a critical particle size of 5-6 nm for nanocrystalline monoclinic ZrO(2) under the present conditions, which is smaller than estimates reported in the literature. Thus, very small monoclinic ZrO(2) particles can be obtained using a continuous flow reactor. This is an important result with respect to improvement of the catalytic properties of nanocrystalline ZrO(2).

Critical and supercritical flows in two unstable, mountain rivers, Toutle river system, Washington

USGS Publications Warehouse

Simon, Andrew; Hardison, J. H.

1994-01-01

Critical and supercritical flows are generally considered to be rare occurrences in natural river channels. This paper presents data and results pertaining to the existence of measured critical and supercritical flows at gaging stations on the North Fork Toutle River (NFT) and Toutle River main stem (TR). The data set includes 930 discharge measurements made by the staff of the U.S. Geological Survey, Cascades Volcano Observatory, between 1980 and 1989.

Optical wet steam monitor

DOEpatents

Maxey, Lonnie C.; Simpson, Marc L.

1995-01-01

A wet steam monitor determines steam particle size by using laser doppler velocimeter (LDV) device to produce backscatter light. The backscatter light signal is processed with a spectrum analyzer to produce a visibility waveform in the frequency domain. The visibility waveform includes a primary peak and a plurality of sidebands. The bandwidth of at least the primary frequency peak is correlated to particle size by either visually comparing the bandwidth to those of known particle sizes, or by digitizing the waveform and comparing the waveforms electronically.

Natural gas-assisted steam electrolyzer

DOEpatents

Pham, Ai-Quoc; Wallman, P. Henrik; Glass, Robert S.

2000-01-01

An efficient method of producing hydrogen by high temperature steam electrolysis that will lower the electricity consumption to an estimated 65 percent lower than has been achievable with previous steam electrolyzer systems. This is accomplished with a natural gas-assisted steam electrolyzer, which significantly reduces the electricity consumption. Since this natural gas-assisted steam electrolyzer replaces one unit of electrical energy by one unit of energy content in natural gas at one-quarter the cost, the hydrogen production cost will be significantly reduced. Also, it is possible to vary the ratio between the electricity and the natural gas supplied to the system in response to fluctuations in relative prices for these two energy sources. In one approach an appropriate catalyst on the anode side of the electrolyzer will promote the partial oxidation of natural gas to CO and hydrogen, called Syn-Gas, and the CO can also be shifted to CO.sub.2 to give additional hydrogen. In another approach the natural gas is used in the anode side of the electrolyzer to burn out the oxygen resulting from electrolysis, thus reducing or eliminating the potential difference across the electrolyzer membrane.

Adsorption behaviors of supercritical Lennard-Jones fluid in slit-like pores.

PubMed

Li, Yingfeng; Cui, Mengqi; Peng, Bo; Qin, Mingde

2018-05-18

Understanding the adsorption behaviors of supercritical fluid in confined space is pivotal for coupling the supercritical technology and the membrane separation technology. Based on grand canonical Monte Carlo simulations, the adsorption behaviors of a Lennard-Jones (LJ) fluid in slit-like pores at reduced temperatures over the critical temperature, T c *  = 1.312, are investigated; and impacts of the wall-fluid interactions, the pore width, and the temperature are taken into account. It is found that even if under supercritical conditions, the LJ fluid can undergo a "vapor-liquid phase transition" in confined space, i.e., the adsorption density undergoes a sudden increase with the bulk density. A greater wall-fluid attractive potential, a smaller pore width, and a lower temperature will bring about a stronger confinement effect. Besides, the adsorption pressure reaches a local minimum when the bulk density equals to a certain value, independent of the wall-fluid potential or pore width. The insights in this work have both practical and theoretical significances. Copyright © 2018 Elsevier Inc. All rights reserved.

Apparatus and method for acoustic monitoring of steam quality and flow

DOEpatents

Sinha, Dipen N.; Pantea, Cristian

2016-09-13

An apparatus and method for noninvasively monitoring steam quality and flow and in pipes or conduits bearing flowing steam, are described. By measuring the acoustic vibrations generated in steam-carrying conduits by the flowing steam either by direct contact with the pipe or remotely thereto, converting the measured acoustic vibrations into a frequency spectrum characteristic of the natural resonance vibrations of the pipe, and monitoring the amplitude and/or the frequency of one or more chosen resonance frequencies, changes in the steam quality in the pipe are determined. The steam flow rate and the steam quality are inversely related, and changes in the steam flow rate are calculated from changes in the steam quality once suitable calibration curves are obtained.

Blended polymer materials extractable with supercritical carbon dioxide

NASA Astrophysics Data System (ADS)

Cai, Mei

Supercritical carbon dioxide is drawing more and more attention because of its unique solvent properties along with being environmentally friendly. Historically most of the commercial interests of supercritical carbon dioxide extraction are in the food industry, pharmaceutical industry, environmental preservation and polymer processing. Recently attention has shifted from the extraction of relatively simple molecules to more complex systems with a much broader range of physical and chemical transformations. However the available data show that a lot of commercially valuable substances are not soluble in supercritical carbon dioxide due to their polar structures. This fact really limits the application of SCF extraction technology to much broader industrial applications. Therefore, the study of a polymer's solubility in a given supercritical fluid and its thermodynamic behavior becomes one of the most important research topics. The major objective of this dissertation is to develop a convenient and economic way to enhance the polymer's solubility in supercritical carbon dioxide. Further objective is to innovate a new process of making metal casting parts with blended polymer materials developed in this study. The key technique developed in this study to change a polymer's solubility in SCF CO2 is to thermally blend a commercially available and CO2 non-soluble polymer material with a low molecular weight CO2 soluble organic chemical that acts as a co-solute. The mixture yields a plastic material that can be completely solubilized in SCF CO2 over a range of temperatures and pressures. It also exhibits a variety of physical properties (strength, hardness, viscosity, etc.) depending on variations in the mixture ratio. The three organic chemicals investigated as CO2 soluble materials are diphenyl carbonate, naphthalene, and benzophenone. Two commercial polymers, polyethylene glycol and polystyrene, have been investigated as CO2 non-soluble materials. The chemical

Modeling and Simulation of U-tube Steam Generator

NASA Astrophysics Data System (ADS)

Zhang, Mingming; Fu, Zhongguang; Li, Jinyao; Wang, Mingfei

2018-03-01

The U-tube natural circulation steam generator was mainly researched with modeling and simulation in this article. The research is based on simuworks system simulation software platform. By analyzing the structural characteristics and the operating principle of U-tube steam generator, there are 14 control volumes in the model, including primary side, secondary side, down channel and steam plenum, etc. The model depends completely on conservation laws, and it is applied to make some simulation tests. The results show that the model is capable of simulating properly the dynamic response of U-tube steam generator.

Supercritical fluid extraction and direct fluid injection mass spectrometry for the determination of trichothecene mycotoxins in wheat samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalinoski, H.T.; Udseth, H.R.; Wright, B.W.

1986-10-01

The application of on-line supercritical fluid extraction with chemical ionization mass spectrometry and collision induced dissociation tandem mass spectrometry for the rapid identification of parts-per-million levels of several trichothecene mycotoxins is demonstrated. Supercritical carbon dioxide is shown to allow identification of mycotoxins with minimum sample handling in complex natural matrices (e.g., wheat). Tandem mass spectrometry techniques are employed for unambiguous identification of compounds of varying polarity, and false positives from isobaric compounds are avoided. Capillary column supercritical fluid chromatography-mass spectrometry of a supercritical fluid extract of the same sample was also performed and detection limits in the parts-per-billion range appearmore » feasible.« less

[Effectiveness and limits of the cleaners steam in hospitals].

PubMed

Meunier, O; Meistermann, C; Schwebel, A

2009-05-01

We assessed bactericidal activity of the cleaners steam used for the bio-cleaning of the hospital surfaces. We performed of samples (Rodac) before and after use of cleaner steam and compared with bactericidal effect of disinfecting detergent used in hospital for surfaces. We studied this effectiveness for different time of steam contact. Finally, we wanted to prove, by air sampling, that aero-bio-contamination was possible generated by using cleaners steam. We show that bactericidal effect of the cleaner steam is superior of some tested disinfecting detergent, for the treatment of one square meter till 2 min. This effectiveness diminishes to be just identical in that some disinfecting detergent when use of the cleaner steam is up to two or four square meters surfaces till 2 min. On the other hand, the cleaner steam is less efficient in terms of bacterial destruction when the time of contact steam-soil is superior in 2 min for six square meter surface. The air bacterial pollution, generated by the use of the cleaner steam, is restricted and not significantly augmented if measured in 44 cm above the soil in the course of cleaning. The cleaner steam is indeed a very good equipment for the cleaning of surfaces but it is necessary to respect a time of minimal contact of 2 min for four square meters surfaces treaties to acquire an antibacterial effect at least so important as that acquired with used disinfecting detergent. The disinfection of surfaces is then user-dependent and the time of requested contact is can be not compatible with hospital obligations.

Enantioselective ultra high performance liquid and supercritical fluid chromatography: The race to the shortest chromatogram.

PubMed

Ciogli, Alessia; Ismail, Omar H; Mazzoccanti, Giulia; Villani, Claudio; Gasparrini, Francesco

2018-03-01

The ever-increasing need for enantiomerically pure chiral compounds has greatly expanded the number of enantioselective separation methods available for the precise and accurate measurements of the enantiomeric purity. The introduction of chiral stationary phases for liquid chromatography in the last decades has revolutionized the routine methods to determine enantiomeric purity of chiral drugs, agrochemicals, fragrances, and in general of organic and organometallic compounds. In recent years, additional efforts have been placed on faster, enantioselective analytical methods capable to fulfill the high throughput requirements of modern screening procedures. Efforts in this field, capitalizing on improved chromatographic particle technology and dedicated instrumentation, have led to highly efficient separations that are routinely completed on the seconds time scale. An overview of the recent achievements in the field of ultra-high-resolution chromatography on column packed with chiral stationary phases, both based on sub-2 μm fully porous and sub-3 μm superficially porous particles, will be given, with an emphasis on very recent studies on ultrafast chiral separations. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supercritical fluid chromatography for separation and preparation of tautomeric 7-epimeric spiro oxindole alkaloids from Uncaria macrophylla.

PubMed

Yang, Wenzhi; Zhang, Yibei; Pan, Huiqin; Yao, Changliang; Hou, Jinjun; Yao, Shuai; Cai, Luying; Feng, Ruihong; Wu, Wanying; Guo, Dean

2017-02-05

Increasing challenge arising from configurational interconversion in aqueous solvent renders it rather difficult to isolate high-purity tautomeric reference standards and thus largely hinders the holistic quality control of traditional Chinese medicine (TCM). Spiro oxindole alkaloids (SOAs), as the markers for the medicinal Uncaria herbs, can easily isomerize in polar or aqueous solvent via a retro-Mannich reaction. In the present study, supercritical fluid chromatography (SFC) is utilized to separate and isolate two pairs of 7-epimeric SOAs, including rhynchophylline (R) and isorhynchophylline (IR), corynoxine (C) and corynoxine B (CB), from Uncaria macrophylla. Initially, the solvent that can stabilize SOA epimers was systematically screened, and acetonitrile was used to dissolve and as the modifier in SFC. Then, key parameters of ultra-high performance SFC (ultra-performance convergence chromatography, UPC 2 ), comprising stationary phase, additive in modifier, column temperature, ABPR pressure, and flow rate, were optimized in sequence. Two isocratic UPC 2 methods were developed on the achiral Torus 1-AA and Torus Diol columns, suitable for UV and MS detection, respectively. MCI gel column chromatography fractionated the U. macrophylla extract into two mixtures (R/IR and C/CB). Preparative SFC, using a Viridis Prep Silica 2-EP OBD column and acetonitrile-0.2% diethylamine in CO 2 as the mobile phase, was finally employed for compound purification. As a result, the purity of four SOA compounds was all higher than 95%. Different from reversed-phase HPLC, SFC, by use of water-free mobile phase (inert CO 2 and aprotic modifier), provides a solution to rapid analysis and isolation of tautomeric reference standards for quality control of TCM. Copyright © 2016 Elsevier B.V. All rights reserved.

Extraction of α-humulene-enriched oil from clove using ultrasound-assisted supercritical carbon dioxide extraction and studies of its fictitious solubility.

PubMed

Wei, Ming-Chi; Xiao, Jianbo; Yang, Yu-Chiao

2016-11-01

Clove buds are used as a spice and food flavoring. In this study, clove oil and α-humulene was extracted from cloves using supercritical carbon dioxide extraction with and without ultrasound assistance (USC-CO2 and SC-CO2, respectively) at different temperatures (32-50°C) and pressures (9.0-25.0MPa). The results of these extractions were compared with those of heat reflux extraction and steam distillation methods conducted in parallel. The extracts obtained using these four techniques were analyzed using gas chromatography and gas chromatography/mass spectrometry (GC/MS). The results demonstrated that the USC-CO2 extraction procedure may extract clove oil and α-humulene from clove buds with better yields and shorter extraction times than conventional extraction techniques while utilizing less severe operating parameters. Furthermore, the experimental fictitious solubility data obtained using the dynamic method were well correlated with density-based models, including the Chrastil model, the Bartle model and the Kumar and Johnston model. Copyright © 2016 Elsevier Ltd. All rights reserved.

Intermolecular interactions and the thermodynamic properties of supercritical fluids.

PubMed

Yigzawe, Tesfaye M; Sadus, Richard J

2013-05-21

The role of different contributions to intermolecular interactions on the thermodynamic properties of supercritical fluids is investigated. Molecular dynamics simulation results are reported for the energy, pressure, thermal pressure coefficient, thermal expansion coefficient, isothermal and adiabatic compressibilities, isobaric and isochoric heat capacities, Joule-Thomson coefficient, and speed of sound of fluids interacting via both the Lennard-Jones and Weeks-Chandler-Andersen potentials. These properties were obtained for a wide range of temperatures, pressures, and densities. For each thermodynamic property, an excess value is determined to distinguish between attraction and repulsion. It is found that the contributions of intermolecular interactions have varying effects depending on the thermodynamic property. The maxima exhibited by the isochoric and isobaric heat capacities, isothermal compressibilities, and thermal expansion coefficient are attributed to interactions in the Lennard-Jones well. Repulsion is required to obtain physically realistic speeds of sound and both repulsion and attraction are necessary to observe a Joule-Thomson inversion curve. Significantly, both maxima and minima are observed for the isobaric and isochoric heat capacities of the supercritical Lennard-Jones fluid. It is postulated that the loci of these maxima and minima converge to a common point via the same power law relationship as the phase coexistence curve with an exponent of β = 0.32. This provides an explanation for the terminal isobaric heat capacity maximum in supercritical fluids.

Recovery of cobalt from spent lithium-ion batteries using supercritical carbon dioxide extraction.

PubMed

Bertuol, Daniel A; Machado, Caroline M; Silva, Mariana L; Calgaro, Camila O; Dotto, Guilherme L; Tanabe, Eduardo H

2016-05-01

Continuing technological development decreases the useful lifetime of electronic equipment, resulting in the generation of waste and the need for new and more efficient recycling processes. The objective of this work is to study the effectiveness of supercritical fluids for the leaching of cobalt contained in lithium-ion batteries (LIBs). For comparative purposes, leaching tests are performed with supercritical CO2 and co-solvents, as well as under conventional conditions. In both cases, sulfuric acid and H2O2 are used as reagents. The solution obtained from the supercritical leaching is processed using electrowinning in order to recover the cobalt. The results show that at atmospheric pressure, cobalt leaching is favored by increasing the amount of H2O2 (from 0 to 8% v/v). The use of supercritical conditions enable extraction of more than 95wt% of the cobalt, with reduction of the reaction time from 60min (the time employed in leaching at atmospheric pressure) to 5min, and a reduction in the concentration of H2O2 required from 8 to 4% (v/v). Electrowinning using a leach solution achieve a current efficiency of 96% and a deposit with cobalt concentration of 99.5wt%. Copyright © 2016 Elsevier Ltd. All rights reserved.

Oil shale extraction using super-critical extraction

NASA Technical Reports Server (NTRS)

Compton, L. E. (Inventor)

1983-01-01

Significant improvement in oil shale extraction under supercritical conditions is provided by extracting the shale at a temperature below 400 C, such as from about 250 C to about 350 C, with a solvent having a Hildebrand solubility parameter within 1 to 2 Hb of the solubility parameter for oil shale bitumen.

US PWR steam generator management: An overview

DOE Office of Scientific and Technical Information (OSTI.GOV)

Welty, C.S. Jr.

1997-02-01

This paper provides an overview on the status of steam generator management activities in US PWRs, and includes: (1) an overview of the impact of steam generator problems; (2) a brief discussion of historical damage trends and the current damage mechanism of most concern; (3) a discussion of the elements of {open_quotes}steam generator management{close_quotes}; and (4) a description of the approach being followed to implement a degradation-specific protocol for tubing inspection and repair. This paper was prepared in conjunction with another paper presented during the Plenary Session of this Conference, {open_quotes}Steam Generator Degradation: Current Mitigation Strategies for Controlling Corrosion{close_quotes}, andmore » is provided as a supplement to that material.« less

Fast fluidized bed steam generator

DOEpatents

Bryers, Richard W.; Taylor, Thomas E.

1980-01-01

A steam generator in which a high-velocity, combustion-supporting gas is passed through a bed of particulate material to provide a fluidized bed having a dense-phase portion and an entrained-phase portion for the combustion of fuel material. A first set of heat transfer elements connected to a steam drum is vertically disposed above the dense-phase fluidized bed to form a first flow circuit for heat transfer fluid which is heated primarily by the entrained-phase fluidized bed. A second set of heat transfer elements connected to the steam drum and forming the wall structure of the furnace provides a second flow circuit for the heat transfer fluid, the lower portion of which is heated by the dense-phase fluidized bed and the upper portion by the entrained-phase fluidized bed.

Method and apparatus for dissociating metals from metal compounds extracted into supercritical fluids

DOEpatents

Wai, Chien M.; Hunt, Fred H.; Smart, Neil G.; Lin, Yuehe

2000-01-01

A method for dissociating metal-ligand complexes in a supercritical fluid by treating the metal-ligand complex with heat and/or reducing or oxidizing agents is described. Once the metal-ligand complex is dissociated, the resulting metal and/or metal oxide form fine particles of substantially uniform size. In preferred embodiments, the solvent is supercritical carbon dioxide and the ligand is a .beta.-diketone such as hexafluoroacetylacetone or dibutyldiacetate. In other preferred embodiments, the metals in the metal-ligand complex are copper, silver, gold, tungsten, titanium, tantalum, tin, or mixtures thereof. In preferred embodiments, the reducing agent is hydrogen. The method provides an efficient process for dissociating metal-ligand complexes and produces easily-collected metal particles free from hydrocarbon solvent impurities. The ligand and the supercritical fluid can be regenerated to provide an economic, efficient process.

46 CFR 50.05-20 - Steam-propelled motorboats.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Steam-propelled motorboats. 50.05-20 Section 50.05-20... Application § 50.05-20 Steam-propelled motorboats. (a) The requirements covering design of the propelling... than 40 feet in length and which are propelled by machinery driven by steam shall be in accordance with...

Chemistry of Earth's Putative Steam Atmosphere

NASA Astrophysics Data System (ADS)

Fegley, B.; Schaefer, L.

2007-12-01

The concept of a steam atmosphere generated by impact devolatilization of planetesimals accreted during Earth's formation is over 20 years old (Matsui and Abe, 1986; Lange and Ahrens, 1982). Surprisingly, with the possible exception of a few qualitative remarks, no one has critically assessed this scenario. We use thermochemical equilibrium and, where relevant, thermochemical kinetic calculations to model the chemistry of the "steam" atmosphere produced by impact volatilization of different types of accreting material. We present results for our nominal conditions (1500 K, total P = 100 bar). We also studied the effects of variable temperature and total pressure. The composition of the accreting material is modeled using average compositions of the Orgueil CI chondrite, the Murchison CM2 chondrite, the Allende CV3 chondrite, average ordinary (H, L, LL) chondrites, and average enstatite (EH, EL) chondrites. The major gases released from CI and CM chondritic material are H2O, CO2, H2, H2S, CO, CH4, and SO2 in decreasing order of abundance. About 10% of the atmosphere is CO2. The major gases released from CV chondritic material are CO2, H2O, CO, H2, and SO2 in decreasing order of abundance. About 20% of the total atmosphere is steam. The major gases released from average ordinary chondritic material are H2, CO, H2O, CO2, CH4, H2S, and N2 in decreasing order of abundance. The "steam" atmosphere is predominantly H2 + CO with steam being about 10% of the total atmosphere. The major gases released from EH chondritic material are H2, CO, H2O, CO2, N2, and CH4 in decreasing order of abundance. The "steam" atmosphere is predominantly H2 + CO with about 10% of the total atmosphere as steam. This work was supported by the NASA Astrobiology and Origins Programs.

Optical wet steam monitor

DOEpatents

Maxey, L.C.; Simpson, M.L.

1995-01-17

A wet steam monitor determines steam particle size by using laser doppler velocimeter (LDV) device to produce backscatter light. The backscatter light signal is processed with a spectrum analyzer to produce a visibility waveform in the frequency domain. The visibility waveform includes a primary peak and a plurality of sidebands. The bandwidth of at least the primary frequency peak is correlated to particle size by either visually comparing the bandwidth to those of known particle sizes, or by digitizing the waveform and comparing the waveforms electronically. 4 figures.

Rapid Determination of Two Triterpenoid Acids in Chaenomelis Fructus Using Supercritical Fluid Extraction On-line Coupled with Supercritical Fluid Chromatography.

PubMed

Zhang, Xiaotian; Ji, Feng; Li, Yueqi; He, Tian; Han, Ya; Wang, Daidong; Lin, Zongtao; Chen, Shizhong

2018-01-01

In this study, an on-line supercritical fluid extraction (SFE) and supercritical fluid chromatography (SFC) method was developed for the rapid determination of oleanoic acid and ursolic acid in Chaenomelis Fructus. After optimization of the conditions, the two triterpenoid acids was obtained by SFE using 20% methanol as a modifier at 35°C in 8 min. They were resolved on a Shim-pack UC-X Diol column (4.6 × 150 mm, 3 μm) in 14 min (0 - 10 min, 5 - 10%; 10 - 14 min, 10% methanol in CO 2 ) with a backpressure of 15 MPa at 40°C. The on-line SFE-SFC method could be completed within 40 min (10.79 mg/g dry plant, R s = 2.36), while the ultrasound-assisted extraction and HPLC method required at least 90 min (3.55 mg/g dry plant, R s = 1.92). This on-line SFE-SFC method is powerful to simplify the pre-processing and quantitative analysis of natural products.

RETRAN analysis of multiple steam generator blow down caused by an auxiliary feedwater steam-line break

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feltus, M.A.

1987-01-01

Analysis results for multiple steam generator blow down caused by an auxiliary feedwater steam-line break performed with the RETRAN-02 MOD 003 computer code are presented to demonstrate the capabilities of the RETRAN code to predict system transient response for verifying changes in operational procedures and supporting plant equipment modifications. A typical four-loop Westinghouse pressurized water reactor was modeled using best-estimate versus worst case licensing assumptions. This paper presents analyses performed to evaluate the necessity of implementing an auxiliary feedwater steam-line isolation modification. RETRAN transient analysis can be used to determine core cooling capability response, departure from nucleate boiling ratio (DNBR)more » status, and reactor trip signal actuation times.« less

Evaluation of supercritical cryogen storage and transfer systems for future NASA missions

NASA Technical Reports Server (NTRS)

Arif, Hugh; Aydelott, John C.; Chato, David J.

1990-01-01

Conceptual designs of Space Transportation Vehicles (STV), and their orbital servicing facilities, that utilize supercritical, single phase, cryogenic propellant were established and compared with conventional subcritical, two phases, STV concepts. The analytical study was motivated by the desire to avoid fluid management problems associated with the storage, acquisition and transfer of subcritical liquid oxygen and hydrogen propellants in the low gravity environment of space. Although feasible, the supercritical concepts suffer from STV weight penalties and propellant resupply system power requirements which make the concepts impractical.

Evaluation of supercritical cryogen storage and transfer systems for future NASA missions

NASA Technical Reports Server (NTRS)

Arif, Hugh; Aydelott, John C.; Chato, David J.

1989-01-01

Conceptual designs of Space Transportation Vehicles (STV), and their orbital servicing facilities, that utilize supercritical, single phase, cryogenic propellants were established and compared with conventional subcritical, two phase, STV concepts. The analytical study was motivated by the desire to avoid fluid management problems associated with the storage, acquisition and transfer of subcritical liquid oxygen and hydrogen propellants in the low gravity environment of space. Although feasible, the supercritical concepts suffer from STV weight penalties and propellant resupply system power requirements which make the concepts impractical.

Triticonazole enantiomers: Separation by supercritical fluid chromatography and the effect of the chromatographic conditions.

PubMed

He, Jianfeng; Fan, Jun; Yan, Yilun; Chen, Xiaodong; Wang, Tai; Zhang, Yaomou; Zhang, Weiguang

2016-11-01

Enantiomeric pairs of triticonazole have been successfully separated by supercritical fluid chromatography coupled with a tris(3,5-dimethylphenylcarbamoyl) cellulose-coated chiral stationary phase in this work. The effects of co-solvent, dissolution solvent, flow rate, backpressure, and column temperature have been studied in detail with respect to retention, selectivity, and resolution of triticonazole. As indicated, the co-solvents mostly affected the retention factors and resolution, due to the different molecular structure and polarity. In addition, the dissolution solvents, namely, chloromethanes and alcohols, have been also important for enantioseparation because of the different interaction with stationary phase. Higher flow rate and backpressure led to faster elution of the triticonazole molecules, and the change of column temperature showed slight effect on the resolution of triticonazole racemate. Moreover, a comparative separation experiment between supercritical fluid chromatography and high performance liquid chromatography revealed that chiral supercritical fluid chromatography gave the 3.5 times value of R s /t R2 than high performance liquid chromatography, which demonstrated that supercritical fluid chromatography had much higher separation efficiency. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In Situ Steam Fracture Experiments.

DTIC Science & Technology

1984-12-31

pressure and tempera- ture data for use in validation of multi-phase flow models describing - condensation/vaporization, heat-transfer, and fluid/vapor...provide an excellent base for development and/or verification of steam-fracture models for low- permeability materials where heat transfer is significant...representative of post-shot cavity conditions. Steam flow tests have been performed at S-CUBED in a 3-meter long by 20-centimeter diameter sand column. In

Supercritical nonlinear parametric dynamics of Timoshenko microbeams

NASA Astrophysics Data System (ADS)

Farokhi, Hamed; Ghayesh, Mergen H.

2018-06-01

The nonlinear supercritical parametric dynamics of a Timoshenko microbeam subject to an axial harmonic excitation force is examined theoretically, by means of different numerical techniques, and employing a high-dimensional analysis. The time-variant axial load is assumed to consist of a mean value along with harmonic fluctuations. In terms of modelling, a continuous expression for the elastic potential energy of the system is developed based on the modified couple stress theory, taking into account small-size effects; the kinetic energy of the system is also modelled as a continuous function of the displacement field. Hamilton's principle is employed to balance the energies and to obtain the continuous model of the system. Employing the Galerkin scheme along with an assumed-mode technique, the energy terms are reduced, yielding a second-order reduced-order model with finite number of degrees of freedom. A transformation is carried out to convert the second-order reduced-order model into a double-dimensional first order one. A bifurcation analysis is performed for the system in the absence of the axial load fluctuations. Moreover, a mean value for the axial load is selected in the supercritical range, and the principal parametric resonant response, due to the time-variant component of the axial load, is obtained - as opposed to transversely excited systems, for parametrically excited system (such as our problem here), the nonlinear resonance occurs in the vicinity of twice any natural frequency of the linear system; this is accomplished via use of the pseudo-arclength continuation technique, a direct time integration, an eigenvalue analysis, and the Floquet theory for stability. The natural frequencies of the system prior to and beyond buckling are also determined. Moreover, the effect of different system parameters on the nonlinear supercritical parametric dynamics of the system is analysed, with special consideration to the effect of the length-scale parameter.

Didanosine polymorphism in a supercritical antisolvent process.

PubMed

Bettini, R; Menabeni, R; Tozzi, R; Pranzo, M B; Pasquali, I; Chierotti, M R; Gobetto, R; Pellegrino, L

2010-04-01

Solid-state properties of active ingredients are crucial in pharmaceutical development owing to their significant clinical and economical implications. In the present work we investigated the solid-state properties and the solubility in water of didanosine, DDI, re-crystallized from a dimethylsulfoxide solution using supercritical CO(2) as an antisolvent (SAS process) for comparison with the commercially available drug product. We also applied modern solid-state NMR (SS NMR) techniques, namely 2D (1)H DQ CRAMPS (Combined Rotation And Multiple Pulse Spectroscopy) and (1)H-(13)C on- and off-resonance CP (cross polarization) FSLG-HETCOR experiments, known for providing reliable information about (1)H-(1)H and (1)H-(13)C intra- and intermolecular proximities, in order to address polymorphism issues arising from the crystallization of a new form in the supercritical process. A new polymorph of didanosine was obtained from the supercritical antisolvent process and characterized by means of 1D and 2D multinuclear ((1)H, (13)C, (15)N) SS NMR. The particle size of the new crystal phase was reduced by varying the antisolvent density through a pressure increase. The structural differences between the commercial product and the SAS re-crystallized DDI are highlighted by X-ray diffractometry and well described by solid-state NMR. The carbon C6 (13)C chemical shift suggests that both commercial and re-crystallized didanosine samples are in the enol form. The analysis of homo- and heteronuclear proximities obtained by means of 2D NMR experiments shows that commercial and SAS re-crystallized DDI possess very similar molecular conformation and hydrogen bond network, but different packing. The new polymorph proved to be a metastable form at ambient conditions, showing higher solubility in water and lower stability to mechanical stress. 2009 Wiley-Liss, Inc. and the American Pharmacists Association

49 CFR 230.63 - Smoke box, steam pipes and pressure parts.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Smoke box, steam pipes and pressure parts. 230.63... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Steam Pipes § 230.63 Smoke box, steam pipes and pressure parts. The smoke box, steam pipes and...

Application of supercritical antisolvent method in drug encapsulation: a review

PubMed Central

Kalani, Mahshid; Yunus, Robiah

2011-01-01

The review focuses on the application of supercritical fluids as antisolvents in the pharmaceutical field and demonstrates the supercritical antisolvent method in the use of drug encapsulation. The main factors for choosing the solvent and biodegradable polymer to produce fine particles to ensure effective drug delivery are emphasized and the effect of polymer structure on drug encapsulation is illustrated. The review also demonstrates the drug release mechanism and polymeric controlled release system, and discusses the effects of the various conditions in the process, such as pressure, temperature, concentration, chemical compositions (organic solvents, drug, and biodegradable polymer), nozzle geometry, CO2 flow rate, and the liquid phase flow rate on particle size and its distribution. PMID:21796245

First direct observations linking confined supercritical turbidity currents to their depositional architecture and facies characteristics

NASA Astrophysics Data System (ADS)

Hage, S.; Cartigny, M.; Hughes Clarke, J. E.; Clare, M. A.; Sumner, E.; Hubbard, S. M.; Talling, P.; Lintern, G.; Stacey, C.; Vardy, M. E.; Hunt, J.; Vendettuoli, D.; Yokokawa, M.; Hizzett, J. L.; Vellinga, A. J.; Azpiroz, M.

2017-12-01

Turbidity currents transfer globally significant amounts of sediment via submarine channels from the continental margin to deep submarine fans. Submarine channel inception is thought to result from erosive, supercritical turbidity currents that are common in proximal settings of the marine realm. Recent monitoring of submarine processes have provided the first measurements of supercritical turbidity currents (Hughes Clarke, 2016), demonstrating that they drive the upstream migration of crescentic bedforms in confined submarine channels. Although upstream-migrating bedforms are common in confined channels across the world's oceans, there is considerable debate over the type of deposits that they produce. It is important to understand what types of deposit record these supercritical bedforms to potentially identify them from geological archives. For the first time, we combine direct measurements from supercritical field-scale turbidity currents with the facies and depositional architecture resulting from such flows. We show how the subsurface architecture evolves in a highly active channel at Squamish submarine delta, British Columbia, Canada. Repeated upstream migration of bedforms is found to create two main deposit geometries. First, regular back-stepping beds result from flow deceleration on the slightly-inclined sides of the bedforms. Second, lens-shaped scour fills composed of massive deposits result from erosion of the back-stepping beds by subsequent turbidity currents. We relate our findings to a range of ancient outcrop studies to demonstrate that supercritical flows are common in proximal settings through the geological record. This study provides the first direct observation-based model to identify confined supercritical turbidity currents and their associated upslope-migrating bedforms in the sedimentary record. This is important for correctly identifying the proximal sites of ancient submarine channels that served as past conduits for globally

Review of surface steam sterilization for validation purposes.

PubMed

van Doornmalen, Joost; Kopinga, Klaas

2008-03-01

Sterilization is an essential step in the process of producing sterile medical devices. To guarantee sterility, the process of sterilization must be validated. Because there is no direct way to measure sterility, the techniques applied to validate the sterilization process are based on statistical principles. Steam sterilization is the most frequently applied sterilization method worldwide and can be validated either by indicators (chemical or biological) or physical measurements. The steam sterilization conditions are described in the literature. Starting from these conditions, criteria for the validation of steam sterilization are derived and can be described in terms of physical parameters. Physical validation of steam sterilization appears to be an adequate and efficient validation method that could be considered as an alternative for indicator validation. Moreover, physical validation can be used for effective troubleshooting in steam sterilizing processes.

Nucleosynthesis inside Supernova-Driven Supercritical Accretion Disks

NASA Astrophysics Data System (ADS)

Fujimoto, Shin-Ichirou; Arai, Kenzo; Matsuba, Ryuichi; Hashimoto, Masa-Aki; Koike, Osamu; Mineshige, Shin

2001-06-01

We have investigated nucleosynthesis in a supercritical accretion disk around a compact object of 1.4Msolar, using the self-similar solution of an optically thick advection dominated flow. Supercritical accretion is expected to occur in a supernova with fallback material accreting onto a new-born compact object. It has been found that appreciable nuclear reactions take place even for a reasonable value of the viscosity parameter, αvissimeq 0.01, when the accretion rate dot{m}=dot{M}c2/(16LEdd) > 105, where LEdd is the Eddington luminosity. If dot{m} ge 4 × 106, all heavy elements are destroyed to 4He through photodisintegrations at the inner part of the disk. Even 4He is also disintegrated to protons and neutrons near the inner edge when dot{m} ge 2 × 107. If the fallback matter of the supernova explosion has the composition of a helium-rich layer of the progenitor, a considerable amount of 44Ti could be ejected via a jet from the disk.

Supercritical Water Experimental Setup for µSR

NASA Astrophysics Data System (ADS)

Liu, Guangdong; Chen, Yanggang; Morrison, Alexander H.; Koda, Akihiro; Percival, Paul W.; Ghandi, Khashayar

The Canadian design for Generation IV nuclear reactors uses supercritical water (SCW, water above its critical point of 374 °C, 221 bar (1 bar = 100 kPa)) as the coolant. Supercritical water-cooled reactors (SCWRs) are designed towards sustainability, economic benefits, improved safety, and longer lifespan. Despite the potential advantages of SCWRs, we know very little about the kinetics of radiolysis products that are formed in them because of the limitations of experimental instruments under the extreme conditions of SCW. The radiolysis products can accumulate over time and create a very corrosive environment. Our group has developed and tested an apparatus suitable for muon spin rotation (µSR) studies of water and aqueous solutions up to 550 °C and 250 bar, close to the conditions at the reactor outlet of the proposed Canadian SCWR design (625 °C and 250 bar). The reaction kinetics information obtained from our setup, together with computer simulations, will aid us in developing chemical control strategies to minimize corrosion in SCWRs.

Patterns of variability in supercritical hadronic systems

NASA Astrophysics Data System (ADS)

Petropoulou, M.; Mastichiadis, A.

2018-07-01

A unique and often overlooked property of a source loaded with relativistic protons is that it can become supercritical, i.e. it can undergo an abrupt transition from a radiatively inefficient to a radiatively efficient state once its proton energy density exceeds a certain threshold. In this paper, we investigate the temporal variability of hadronic systems in this hardly explored regime. We show that there exists a range of proton densities that prevent the system from reaching a steady state, but drive it instead in a quasi-periodic mode. The escaping radiation then exhibits limit cycles, even if all physical parameters are held constant in time. We extend our analysis to cases where the proton injection rate varies with time and explore the variability patterns of escaping radiation as the system moves in and out from the supercritical regime. We examine the relevance of our results to the variability of the prompt gamma-ray burst emission and show that, at least on a phenomenological level, some interesting analogies exist.

Method of steam reforming methanol to hydrogen

DOEpatents

Beshty, Bahjat S.

1990-01-01

The production of hydrogen by the catalyzed steam reforming of methanol is accomplished using a reformer of greatly reduced size and cost wherein a mixture of water and methanol is superheated to the gaseous state at temperatures of about 800.degree. to about 1,100.degree. F. and then fed to a reformer in direct contact with the catalyst bed contained therein, whereby the heat for the endothermic steam reforming reaction is derived directly from the superheated steam/methanol mixture.

Effect of sub- and supercritical CO2 treatment on the properties of Pseudomonas cepacia lipase.

PubMed

Chen, Dawei; Zhang, Houjin; Xu, Jing; Yan, Yunjun

2013-07-10

In this work, we have investigated the influences of sub- and supercritical CO2 treatment on the properties of Pseudomonas cepacia lipase (PCL), including its esterification and transesterification activities, structural changes and stability. Results demonstrated that exposure time to subcritical CO2 treatment had a negative effect on PCL transesterification activity whereas exposure time to supercritical CO2 treatment had a positive effect. But generally, most compressed treatments significantly enhanced PCL esterification activity. Conformational analysis by FT-IR and fluorescence emission spectra revealed that enhanced activities after supercritical CO2 treatment were correlated with the secondary and tertiary structural changes of PCL. Secondary structure changes also appeared to be responsible for enhancement of PCL activities by subcritical CO2 treatment. Compared to native PCL, treated PCL's esterification activity significantly decreased in hydrophilic organic media, while transesterification activity significantly increased in tert-amyl alcohol and acetone. After supercritical treatment, the thermal stability of PCL significantly decreased in esterification reactions, however, there was no significant difference in transesterification reactions. Copyright © 2013 Elsevier Inc. All rights reserved.

Multifuel industrial steam generation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mesko, J.E.

An inefficient, unreliable steam generation and distribution system at the Red River Army Depot (Texarkana, Tex.), a major industrial facility of the federal government, was replaced with a modern, multifuel-burning steam plant. In the new plant, steam is generated by three high-pressure field-erected boilers burning 100 percent coal, 100 percent refuse, or any combination of the two, while maintaining particulate emissions, SO{sub 2} concentration, and NO{sub x} and chlorine levels at or better than clean air standards. The plant, which has been in operation since 1986, is now part of the Army's Energy/Environment Showcase for demonstrating innovative technology to publicmore » and private operators. When the project began, the Red River depot faced several operational problems. Existing No. 2 oil- and gas- fired boilers in three separate boiler plants were inefficient, unreliable, and difficult to maintain. Extra boilers often had to be leased to provide for needed capacity. In addition, the facility had large quantities of waste to dispose of.« less

A flow-through column electrolytic cell for supercritical fluid chromatography.

PubMed

Yamamoto, Kazuhiro; Ueki, Tatsuya; Higuchi, Naoyuki; Takahashi, Kouji; Kotani, Akira; Hakamata, Hideki

2017-10-01

A novel flow-through column electrolytic cell was proposed as a detector to obtain current signals for supercritical fluid chromatography. The electrochemical cell consisted of two electrodes and its holder, and a working and a counter electrode were fabricated from 192 carbon strings, which were composed of 400 carbon fibers of 10 μm in diameter filled into a heat-shrinkable tube. These electrodes were placed in the center of a holder made from polyether ether ketone blocks and they were separated by polytetrafluoroethylene membrane filters. To evaluate the sensitivity of this cell, a standard solution of ferrocene was injected into the supercritical fluid chromatography system connected to the electrolytic cell. The ferrocene was eluted through a silica gel column using a mixture of a mobile phase of supercritical CO 2 and a modifier of methanol containing ammonium acetate. The current peak area of ferrocene correlated to the ferrocene concentration in the range of 10-400 μmol/L (r = 0.999). Moreover, the limit of detection on the column estimated from a signal-to-noise ratio of 3 was 9.8  × 10 -13  mol. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A three step supercritical process to improve the dissolution rate of eflucimibe.

PubMed

Rodier, Elisabeth; Lochard, Hubert; Sauceau, Martial; Letourneau, Jean-Jacques; Freiss, Bernard; Fages, Jacques

2005-10-01

The aim of this study is to improve the dissolution properties of a poorly-soluble active substance, Eflucimibe by associating it with gamma-cyclodextrin. To achieve this objective, a new three-step process based on supercritical fluid technology has been proposed. First, Eflucimibe and cyclodextrin are co-crystallized using an anti-solvent process, dimethylsulfoxide being the solvent and supercritical carbon dioxide being the anti-solvent. Second, the co-crystallized powder is held in a static mode under supercritical conditions for several hours. This is the maturing step. Third, in a final stripping step, supercritical CO(2) is flowed through the matured powder to extract the residual solvent. The coupling of the first two steps brings about a significant synergistic effect to improve the dissolution rate of the drug. The nature of the entity obtained at the end of each step is discussed and some suggestions are made as to what happens in these operations. It is shown the co-crystallization ensures a good dispersion of both compounds and is rather insensitive to the operating parameters tested. The maturing step allows some dissolution-recrystallization to occur thus intensifying the intimate contact between the two compounds. Addition of water is necessary to make maturing effective as this is governed by the transfer properties of the medium. The stripping step allows extraction of the residual solvent but also removes some of the Eflucimibe which is the main drawback of this final stage.

Cytotoxic Deoxypodophyllotoxin Can Be Extracted in High Purity from Anthriscus sylvestris Roots by Supercritical Carbon Dioxide.

PubMed

Seegers, Christel L C; Tepper, Pieter G; Setroikromo, Rita; Quax, Wim J

2018-05-01

Deoxypodophyllotoxin is present in the roots of Anthriscus sylvestris . This compound is cytotoxic on its own, but it can also be converted into podophyllotoxin, which is in high demand as a precursor for the important anticancer drugs etoposide and teniposide. In this study, deoxypodophyllotoxin is extracted from A. sylvestris roots by supercritical carbon dioxide extraction. The process is simple and scalable. The supercritical carbon dioxide method extracts 75 - 80% of the total deoxypodophyllotoxin content, which is comparable to a single extraction by traditional Soxhlet. However, less polar components are extracted. The activity of the supercritical carbon dioxide extract containing deoxypodophyllotoxin was assessed by demonstrating that the extract arrests A549 and HeLa cells in the G 2 /M phase of the cell cycle. We conclude that biologically active deoxypodophyllotoxin can be extracted from A. sylvestris by supercritical carbon dioxide extraction. The method is solvent free and more sustainable compared to traditional methods. Georg Thieme Verlag KG Stuttgart · New York.

High-power ultrasonic system for the enhancement of mass transfer in supercritical CO2 extraction processes

NASA Astrophysics Data System (ADS)

Riera, Enrique; Blanco, Alfonso; García, José; Benedito, José; Mulet, Antonio; Gallego-Juárez, Juan A.; Blasco, Miguel

2010-01-01

Oil is an important component of almonds and other vegetable substrates that can show an influence on human health. In this work the development and validation of an innovative, robust, stable, reliable and efficient ultrasonic system at pilot scale to assist supercritical CO2 extraction of oils from different substrates is presented. In the extraction procedure ultrasonic energy represents an efficient way of producing deep agitation enhancing mass transfer processes because of some mechanisms (radiation pressure, streaming, agitation, high amplitude vibrations, etc.). A previous work to this research pointed out the feasibility of integrating an ultrasonic field inside a supercritical extractor without losing a significant volume fraction. This pioneer method enabled to accelerate mass transfer and then, improving supercritical extraction times. To commercially develop the new procedure fulfilling industrial requirements, a new configuration device has been designed, implemented, tested and successfully validated for supercritical fluid extraction of oil from different vegetable substrates.

[Colorectal cancer preventive effect of combined administration of phenolic acids and supercritical extracts from Angelica sinensis].

PubMed

Peng, Yu; Zhao, Bo-Chen; Kang, Qian; Liu, Jia; Chen, Cheng; Li, Bing-Shao; Xie, Yuan-Ping; Wu, Qing

2018-03-01