WorldWideScience

Sample records for technology supercritical carbon

  1. EVALUATION OF SUPERCRITICAL CARBON DIOXIDE TECHNOLOGY TO REDUCE SOLVENT IN SPRAY COATING APPLICATIONS

    Science.gov (United States)

    This evaluation, part of the Pollution Prevention Clean Technology Demonstration (CTD) Program, addresses the product quality, waste reduction, and economic issues of spray paint application using supercritical carbon dioxide (CO2). Anion Carbide has developed this technology and...

  2. EVALUATION OF SUPERCRITICAL CARBON DIOXIDE TECHNOLOGY TO REDUCE SOLVENT IN SPRAY COATING APPLICATIONS

    Science.gov (United States)

    This evaluation, part of the Pollution Prevention Clean Technology Demonstration (CTD) Program, addresses the product quality, waste reduction, and economic issues of spray paint application using supercritical carbon dioxide (CO2). Anion Carbide has developed this technology and...

  3. Supercritical carbon dioxide (SC-CO2 as a clean technology for palm kernel oil extraction

    Directory of Open Access Journals (Sweden)

    Norhuda I

    2009-04-01

    Kyoto Protocol. Keywords: By-product, Solvent extraction, Kyoto protocol, Supercritical Carbon Dioxide, Palm Kernel Oil Received: 13 July 2008 / Received in revised form: 17 February 2009, Accepted: 28 February 2009, Published online: 12 March 2009

  4. The Application of the Supercritical Carbon Dioxide Fluid Extraction Technology on the Extraction of Micro Amount of Uranium

    Institute of Scientific and Technical Information of China (English)

    SONG; Zhi-jun; YU; Zhen; LIANG; Xiao-hu; DING; You-qian

    2012-01-01

    <正>The characteristic of solid radioactive wastes containing less 1% uranium, such as mine tailings, contaminated soil and sludge, is complex matrix and irregular surface. The traditional treatment technology usually consumes a lot of chemical reagents and produces a large amount of secondary wastes. The supercritical fluid has the advantage of high diffusivity, low viscosity, and liquid-like solvating capability, which enable the supercritical carbon dioxide fluid extraction (SFE) technology to be a alternative method to extract micro amount of uranium from solid radioactive wastes.

  5. Supercritical carbon dioxide and polymers : an interplay of science and technology

    NARCIS (Netherlands)

    Picchioni, Francesco

    The increasing use of supercritical carbon dioxide (scCO(2)) as a green solvent for polymer synthesis and processing reflects a still growing interest at academic and industrial level. The peculiar characteristics of scCO(2), namely its plasticizing effect on polymeric structures and the enhanced

  6. SEMICONDUCTOR TECHNOLOGY Supercritical carbon dioxide process for releasing stuck cantilever beams

    Science.gov (United States)

    Yu, Hui; Chaoqun, Gao; Lei, Wang; Yupeng, Jing

    2010-10-01

    The multi-SCCO2 (supercritical carbon dioxide) release and dry process based on our specialized SCCO2 semiconductor process equipment is investigated and the releasing mechanism is discussed. The experiment results show that stuck cantilever beams were held up again under SCCO2 high pressure treatment and the repeatability of this process is nearly 100%.

  7. Drying of supercritical carbon dioxide with membrane processes

    NARCIS (Netherlands)

    Lohaus, Theresa; Scholz, Marco; Koziara, Beata T.; Benes, N.E.; Wessling, Matthias

    2015-01-01

    In supercritical extraction processes regenerating the supercritical fluid represents the main cost constraint. Membrane technology has potential for cost efficient regeneration of water-loaded supercritical carbon dioxide. In this study we have designed membrane-based processes to dehydrate water-l

  8. Loading amorphous Asarone in mesoporous silica SBA-15 through supercritical carbon dioxide technology to enhance dissolution and bioavailability.

    Science.gov (United States)

    Zhang, Zhengzan; Quan, Guilan; Wu, Qiaoli; Zhou, Chan; Li, Feng; Bai, Xuequn; Li, Ge; Pan, Xin; Wu, Chuanbin

    2015-05-01

    The aim of this study was to load amorphous hydrophobic drug into ordered mesoporous silica (SBA-15) by supercritical carbon dioxide technology in order to improve the dissolution and bioavailability of the drug. Asarone was selected as a model drug due to its lipophilic character and poor bioavailability. In vitro dissolution and in vivo bioavailability of the obtained Asarone-SBA-15 were significantly improved as compared to the micronized crystalline drug. This study offers an effective, safe, and environmentally benign means of solving the problems relating to the solubility and bioavailability of hydrophobic molecules.

  9. Supercritical fluid technology

    Energy Technology Data Exchange (ETDEWEB)

    Penninger, J.M.L.; McHugh, M.A.; Radosz, M.; Krukonis, V.J.

    1985-01-01

    This book presents the state-of-the-art in the science and technology of supercritical fluid (scf) processing. Current research as described in the book, focuses on developments in equations of state for binary and multicomponent mixtures (including polymer solutions), solubility measurements at near-critical conditions, measurements of critical properties of binary mixtures and their correlation with equations of state. Progress in thermodynamics, coupled with advances in the design and construction of high pressure equipment, has opened up a wide avenue of commercial application (e.g. decaffeination of coffee beans, extractions of flavours and spices, purification of pharmaceutical products, separations of polymeric materials, deodorization and deacidification of vegetable oils, fractionation of fatty acids, coal liquefaction, wood delignitication, etc.)

  10. Recuperative supercritical carbon dioxide cycle

    Science.gov (United States)

    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.

  11. Pulsed discharge plasmas in supercritical carbon dioxide

    OpenAIRE

    Kiyan, Tsuyoshi; Uemura, A.; Tanaka, K.; Zhang, C. H.; Namihira, Takao; Sakugawa, Takashi; Katsuki, Sunao; Akiyama, Hidenori; Roy, B.C.; Sasaki, M.; Goto, M.; キヤン, ツヨシ; ナミヒラ, タカオ; サクガワ, タカシ; カツキ, スナオ

    2005-01-01

    In recent years, several studies about electrical discharge plasma in supercritical carbon dioxide (CO2) have been carried out. One of the unique characteristics of supercritical fluid is a large density fluctuation near the critical point that can result in marked dramatic changes of thermal conductivity. Therefore, the electrical discharge plasma produced in supercritical fluid has unique features and reactions unlike those of normal plasma produced in gas phase. In our experiments, two typ...

  12. Antifouling foldable acrylic IOLs loaded with norfloxacin by aqueous soaking and by supercritical carbon dioxide technology.

    Science.gov (United States)

    González-Chomón, Clara; Braga, Mara E M; de Sousa, Herminio C; Concheiro, Angel; Alvarez-Lorenzo, Carmen

    2012-10-01

    Cataracts treatment usually involves the extraction of the opaque crystalline lens and its replacement by an intraocular lens (IOL). A serious complication is the occurrence of endophthalmitis, a post-surgery infection mainly caused by Staphylococcus epidermidis, Staphylococcus aureus, and Pseudomonas aeruginosa. IOLs having the ability to load and to release norfloxacin in a controlled way and at efficient therapeutic levels may help to overcome these issues. In this work, acrylic hydrogels combining 2-hydroxyethyl methacrylate (HEMA) and 2-butoxyethyl methacrylate (BEM) at various ratios were prepared to attain biocompatible networks that can be foldable even in the dry state and thus insertable through minor ocular incision, and that load therapeutic amounts of norfloxacin. Acrylamide (AAm) and methacrylic acid (MAAc) were also incorporated as functional comonomers in small proportions. Water sorption, contact angle, protein adsorption, and optical properties of the networks were characterized. BEM notably decreased the T(g) of the networks, but also the loading by immersion in aqueous solution (presoaking). Then, a scCO(2)-based impregnation/deposition (SSI) method was implemented to improve the uptake of the drug. Loading capacities were discussed in terms of the comonomers composition and the employed method and operational conditions. The networks prepared with HEMA/BEM 20:80 vol/vol and processed with supercritical fluids combine adequate mechanical properties, biocompatibility and norfloxacin loading/release, and seem to be suitable for developing norfloxacin-eluting IOLs. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Thermodynamic properties of supercritical carbon dioxide: Widom and Frenkel lines

    Science.gov (United States)

    Fomin, Yu. D.; Ryzhov, V. N.; Tsiok, E. N.; Brazhkin, V. V.

    2015-02-01

    Supercritical fluids are widely used in a number of important technological applications, yet the theoretical progress in the field has been rather moderate. Fairly recently, a new understanding of the liquidlike and gaslike properties of supercritical fluids has come to the fore, particularly with the advent of the Widom and Frenkel lines that aim to demarcate different physical properties on the phase diagram. Here, we report the results of a computational study of supercritical carbon dioxide, one of the most important fluids in the chemical industry. We study the response functions of CO2 in the supercritical state and calculate the locations of their maxima (Widom lines). We also report the preliminary calculations of the Frenkel line, the line of crossover of microscopic dynamics of particles. Our insights are relevant to physical processes in the atmosphere of Venus and its evolution.

  14. Estimation of the Isotherms of Phenol on Activated Carbons and Polymeric Adsorbents under Supercritical Condition

    Institute of Scientific and Technical Information of China (English)

    奚红霞; 谢兰英; 李祥斌; 李忠

    2003-01-01

    A method named as "volume-expanding and pressure-reducing adsorption" is proposed. It can be used to measure the isotherms under supercritical condition. The adsorption isotherms of phenol on activated carbons and polymeric adsorbents are estimated and compared respectively for the systems of "phenol-activated carbon-supercritical fluid CO2" and "phenol-polymeric adsorbent-supercritical fluid CO2". The results show that the amount of phenol adsorbed on the activated carbons and the polymeric adsorbents under the supercritical condition is much less than that under the general condition, which can be utilized to develop a technology regenerating the activated carbon with supercritical fluid. Moreover, the effects of ethyl alcohol, used as the third component, on the isotherms of phenol on the activated carbons and polymeric adsorbents under the supercritical condition are also investigated.

  15. Water in supercritical carbon dioxide dyeing

    Directory of Open Access Journals (Sweden)

    Zheng Lai-Jiu

    2015-01-01

    Full Text Available This paper investigates the effect of water serving as entrainer on the dyeing of wool fabrics in supercritical carbon dioxide. Compared with previous supercritical dyeing methods, addition of water makes the dyeing process more effective under low temperature and low pressure. During dyeing process, dyestuff can be uniformly distributed on fabrics’s surface due to water interaction, as a result coloration is enhanced while color difference is decreased.

  16. Supercritical carbon dioxide hop extraction

    Directory of Open Access Journals (Sweden)

    Pfaf-Šovljanski Ivana I.

    2005-01-01

    Full Text Available The hop of Magnum cultivar was extracted using supercritical carbon dioxide (SFE-as extractant. Extraction was carried out in the two steps: the first one being carried out at 150 bar and 40°C for 2.5 h (Extract A, and the second was the extraction of the same hop sample at 300 bar and 40°C for 2.5 h (Extract B. Extraction kinetics of the system hop-SFE-CO2 was investigated. Two of four most common compounds of hop aroma (α-humulene and β-caryophyllene were detected in Extract A. Isomerised α-acids and β-acids were detected too. a-Acid content in Extract B was high (that means it is a bitter variety of hop. Mathematical modeling using empirical model characteristic time model and simple single sphere model has been performed on Magnum cultivar extraction experimental results. Characteristic time model equations, best fitted experimental results. Empirical model equation, fitted results well, while simple single sphere model equation poorly approximated the results.

  17. Pharmaceutical applications of supercritical carbon dioxide.

    Science.gov (United States)

    Kaiser, C S; Römpp, H; Schmidt, P C

    2001-12-01

    The appearance of a supercritical state was already observed at the beginning of the 19th century. Nevertheless, the industrial extraction of plant and other natural materials started about twenty years ago with the decaffeination of coffee. Today carbon dioxide is the most common gas for supercritical fluid extraction in food and pharmaceutical industry. Since pure supercritical carbon dioxide is a lipophilic solvent, mixtures with organic solvents, especially alcohols, are used to increase the polarity of the extraction fluid; more polar compounds can be extracted in this way. The main fields of interest are the extraction of vegetable oils from plant material in analytical and preparative scale, the preparation of essential oils for food and cosmetic industry and the isolation of substances of pharmaceutical relevance. Progress in research was made by the precise measurement of phase equilibria data by means of different methods. Apart from extraction, supercritical fluid chromatography was introduced in the field of analytics, as well as micro- and nanoparticle formation using supercritical fluids as solvent or antisolvent. This review presents pharmaceutical relevant literature of the last twenty years with special emphasis on extraction of natural materials.

  18. Diiodination of Alkynes in supercritical Carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    李金恒; 谢叶香; 尹笃林; 江焕峰

    2003-01-01

    A general,green and efficient method for the synthesis of transdiiodoalkenes in CO2(sc) has been developed.Trans-diiodoalkenes were obtained stereospecifically in quantitative yields via diiodination of both electron-rich and electron-deficient alkynes in the presence of KI,Ce(SO4)2 and water in supercritical carbon dioxide [CO2(sc)]at 40℃.

  19. 牛蒡根挥发油超临界CO2萃取的工艺研究%Technology for volatile oil extraction from the root of Arctium Lappa L.using supercrit-ical carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    窦德宇; 柳春燕; 杨丽芬

    2013-01-01

      目的:对超临界CO2流体萃取牛蒡根挥发油的工艺条件进行研究。方法:通过单因素试验研究萃取温度、萃取压力、萃取时间对萃取率的影响,并采用正交试验设计优化工艺条件。结果:最佳萃取条件为萃取温度45℃、萃取压力25 MPa、萃取时间1.5h,在此条件下,超临界CO2流体萃取牛蒡根挥发油的萃取率为2.92%。结论:超临界CO2流体萃取牛蒡根挥发油具有较高的萃取率,最佳条件为萃取温度45℃、萃取压力25 MPa、萃取时间1.5 h,且萃取温度对萃取率有显著影响。%  Objective:To study the technology for extracting volatile oil from the root of Arctium Lappa L.using supercritical carbon dioxide. Methods:By single factor test,the effects on the yield were examined con-cerning the extraction temperature,pressure and time.Orthogonal experi-ment was used to optimize the extraction technology.Results:The optimal temperature was 45 ℃,pressure at 25 MPa and duration for 1.5 h.Such conditions had led to a yield of volatile oil by 2.92%.Conclusion:Ex-traction of volatile oil from root of Arctium Lappa L.using supercritical carbon dioxide can be productive under the optimum conditions described above.Of the three factors,extraction temperature may greatly affect the extraction yield of volatile oil.

  20. Remediation of Contaminated Soils By Supercritical Carbon Dioxide Extraction

    Science.gov (United States)

    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

  1. Dye solubility in supercritical carbon dioxide fluid

    Directory of Open Access Journals (Sweden)

    Yan Jun

    2015-01-01

    Full Text Available Supercritical carbon dioxide fluid is an alternative solvent for the water of the traditional dyeing. The solubility of dyestuff affects greatly the dyeing process. A theoretical model for predicting the dye solubility is proposed and verified experimentally. The paper concludes that the pressure has a greater impact on the dyestuff solubility than temperature, and an optimal dyeing condition is suggested for the highest distribution coefficient of dyestuff.

  2. Supercritical fluids technology for clean biofuel production

    Institute of Scientific and Technical Information of China (English)

    Dongsheng Wen; H.Jiang; Kai Zhang

    2009-01-01

    Biofuels are liquid or gaseous fuels that are predominantly produced from biomass for transport sector applications.As biofuels are renewable,sustainable,carbon neutral and environmentally benign,they have been proposed as promising alternative fuels for gasoline and diesel engines.This paper reviews state-of-the-art application of the supercritical fluid(SCF)technique in biofuels production that includes biodiesel from vegetable oils via the transesterification process,bio-hydrogen from the gasification and bio-oil from the lique-faction of biomass,with biodiesel production as the main focus. The global biofuel situation and biofuel economics are also reviewed.The SCF has been shown to be a promising technique for future large-scale biofuel production,especially for biodiesel production from waster oil and fat.Compared with conventional biofuel production methods,the SCF technology possesses a number of advantages that includes fast inetics,high fuel production rate,ease of continuous operation and elimination of the necessity of catalysts.The harsh operation environment,i.e. the high temperature and high pressure,and its request on the materials and associated cost are the main concerns for its wide application.

  3. Use of supercritical carbon dioxide extraction

    Energy Technology Data Exchange (ETDEWEB)

    Taniguchi, Masayuki (Niigata Univ., Faculty of Engineering, Niigata, (Japan))

    1989-09-25

    Supercritical fluid extraction is a novel diffusion and separation technique which exploits simultaneously the increase of vapor pressure and the difference of chemical affinities of fluids near the critical point. A solvent which is used as the supercritical fluid has the following features: the critical point exists in the position of relatively ease of handling, the solvent is applicable to the extraction of a physiological active substance of thermal instability. Carbon dioxide as the solvent is non-flammable, non-corrosive, non-toxic, cheap, and readily available of high purity. The results of studies on the use of supercritical carbon dioxide (SC-CO{sub 2}) as a solvent for natural products in the fermentation and food industries, were collected. SC-CO{sub 2} extraction are used in many fields, examples for the application are as follows: removal of organic solvents from antibiotics; extraction of vegetable oils contained in wheat germ oil, high quality mustard seeds, rice bran and so on; brewing of sake using rice and rice-koji; use as a non-aqueous medium for the synthesis of precursors of the Aspartame; and use in sterilization. 66 refs., 17 figs., 21 tabs.

  4. A comparison between molten carbonate fuel cells based hybrid systems using air and supercritical carbon dioxide Brayton cycles with state of the art technology

    Science.gov (United States)

    Sánchez, D.; Muñoz de Escalona, J. M.; Chacartegui, R.; Muñoz, A.; Sánchez, T.

    A proposal for high efficiency hybrid systems based on molten carbonate fuel cells is presented in this paper. This proposal is based on adopting a closed cycle bottoming gas turbine using supercritical carbon dioxide as working fluid as opposed to open cycle hot air turbines typically used in this type of power generators. First, both bottoming cycles are compared for the same operating conditions, showing that their performances do not differ as much as initially expected, even if the initial objective of reducing compression work is accomplished satisfactorily. In view of these results, a profound review of research and industrial literature is carried out in order to determine realistic specifications for the principal components of the bottoming systems. From this analysis, it is concluded that an appropriate set of specifications must be developed for each bottoming cycle as the performances of compressor, turbine and recuperator differ significantly from one working fluid to another. Thus, when the operating conditions are updated, the performances of the resulting systems show a remarkable advantage of carbon dioxide based systems over conventional air units. Actually, the proposed hybrid system shows its capability to achieve 60% net efficiency, what represents a 10% increase with respect to the reference system.

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

    Energy Technology Data Exchange (ETDEWEB)

    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 roadmap 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 features

  6. Solubility of climbazole and triclocarban in supercritical carbon dioxide: Measurement and correlation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chan Ik [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Seoul 151-744 (Korea, Republic of); Department of Cosmeceutical Science, Daegu Hanny University, Gyeongsangbuk-do 712-230 (Korea, Republic of); Shin, Moon Sam [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Seoul 151-744 (Korea, Republic of); Kim, Hwayong [School of Chemical and Biological Engineering and Institute of Chemical Processes, Seoul National University, Seoul 151-744 (Korea, Republic of)], E-mail: hwayongk@snu.ac.kr

    2009-01-15

    The supercritical technology has been considered as an appropriate alternative for separation of biomaterials from cosmetic, food, and pharmaceutical products. The solid solubility of biological compounds is the most important thermodynamic parameter in the supercritical extraction and purification. The equilibrium solubility of two biocides, climbazole, and triclocarban was measured in supercritical carbon dioxide with static method in the pressure range from (10 to 40) MPa and at temperatures equal to (313.2, 323.2, and 333.2) K. The experimental data were correlated by Peng-Robinson equation of state and quasi-chemical nonrandom lattice fluid model.

  7. Hydrogel Nanoparticles from Supercritical Technology for Pharmaceutical and Seismological Applications

    Science.gov (United States)

    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

  8. Carbon dioxide-based supercritical fluids as IC manufacturing solvents

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, J.B.; Davenhall, L.B.; Taylor, C.M.V.; Sivils, L.D.; Pierce, T.; Tiefert, K.

    1999-05-11

    The production of integrated circuits (IC's) involves a number of discrete steps which utilize hazardous or regulated solvents and generate large waste streams. ES&H considerations associated with these chemicals have prompted a search for alternative, more environmentally benign solvent systems. An emerging technology for conventional solvent replacement is the use of supercritical fluids based on carbon dioxide (CO{sub 2}). Research work, conducted at Los Alamos in conjunction with the Hewlett-Packard Company, has lead to the development of a CO{sub 2}-based supercritical fluid treatment system for the stripping of hard-baked photoresists. This treatment system, known as Supercritical CO{sub 2} Resist Remover, or CORR, uses a two-component solvent composed of a nonhazardous, non-regulated compound, dissolved in supercritical CO{sub 2}. The solvent/treatment system has been successfully tested on metallized Si wafers coated with negative and positive photoresist, the latter both before and after ion-implantation. A description of the experimental data will be presented. Based on the initial laboratory results, the project has progressed to the design and construction of prototype, single-wafer photoresist-stripping equipment. The integrated system involves a closed-loop, recirculating cycle which continuously cleans and regenerates the CO{sub 2}, recycles the dissolved solvent, and separates and concentrates the spent resist. The status of the current design and implementation strategy of a treatment system to existing IC fabrication facilities will be discussed. Additional remarks will be made on the use of a SCORR-type system for the cleaning of wafers prior to processing.

  9. Supercritical fluids technology in bioprocess industries: A review

    Directory of Open Access Journals (Sweden)

    Kianoush Khosravi Darani

    2009-12-01

    Full Text Available This article reviews the fundamentals of supercritical fluid (SCF science and moves on to the biotechnological applications of them e.g. removal of biostatic agents from fermentation broths, SCF disruption of microorganisms, destruction of industrial waste, the gas-antisolvent crystallization and micron-size particle formation. Also gaining ground is enzymatic catalysis in supercritical carbon dioxide (SC-CO2, which offers the possibility of integrated synthesis product recovery processes. The paper is structured as follows: first, the effects of dense SC-CO2 on the extraction of biomaterials and disruption of cells are thoroughly reported and discussed. Then the application of SC-CO2 in particle formation and modifications of biopolymers and enzymes are described. In general, the article is focused on potential bio-industrial applications and future research needs of the SCF technology. Keywords: Biotechnology, Supercritical Fluids (SCF, disruption, inactivation, extraction, downstream, particle formation Received: 10 October 2009 / Received in revised form: 30 January 2010, Accepted: 30 January 2010, Published online: 10 March 2010

  10. Metal Nanoparticles Preparation In Supercritical Carbon Dioxide Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Harry W. Rollins

    2004-04-01

    The novel optical, electronic, and/or magnetic properties of metal and semiconductor nanoparticles have resulted in extensive research on new methods for their preparation. An ideal preparation method would allow the particle size, size distribution, crystallinity, and particle shape to be easily controlled, and would be applicable to a wide variety of material systems. Numerous preparation methods have been reported, each with its inherent advantages and disadvantages; however, an ideal method has yet to emerge. The most widely applied methods for nanoparticle preparation include the sonochemical reduction of organometallic reagents,(1&2) the solvothermal method of Alivisatos,(3) reactions in microemulsions,(4-6) the polyol method (reduction by alcohols),(7-9) and the use of polymer and solgel materials as hosts.(10-13) In addition to these methods, there are a variety of methods that take advantage of the unique properties of a supercritical fluid.(14&15) Through simple variations of temperature and pressure, the properties of a supercritical fluid can be continuously tuned from gas-like to liquid-like without undergoing a phase change. Nanoparticle preparation methods that utilize supercritical fluids are briefly reviewed below using the following categories: Rapid Expansion of Supercritical Solutions (RESS), Reactive Supercritical Fluid Processing, and Supercritical Fluid Microemulsions. Because of its easily accessible critical temperature and pressure and environmentally benign nature, carbon dioxide is the most widely used supercritical solvent. Supercritical CO2 is unfortunately a poor solvent for many polar or ionic species, which has impeded its use in the preparation of metal and semiconductor nanoparticles. We have developed a reactive supercritical fluid processing method using supercritical carbon dioxide for the preparation of metal and metal sulfide particles and used it to prepare narrowly distributed nanoparticles of silver (Ag) and silver sulfide

  11. Extraction of olive oil with supercritical carbon dioxide / Ilana Geerdts

    OpenAIRE

    Geerdts, Ilana

    2005-01-01

    The principal objective of this study was to extract olive oil from the fruit of Olea europaea by means of supercritical carbon dioxide (sc-C02) as an alternative to traditional methods. Extractions were performed on a laboratory scale supercritical fluid extractor of the latest design, featuring three mutually independent flow systems and extremely high flow rates. A number of extraction runs based on a statistical design was performed to establish the conditions (time, pressu...

  12. Some Organic Reactions in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    JIANG Huan-feng; YANG Xiao-yue; LI Guo-ping; ZOU Gang

    2004-01-01

    Organic reactions in supercritical carbon dioxide (scCO2) have facilitated great progress in recent years 1. ScCO2, as an environmentally friendly reaction medium, may be a substitute for volatile and toxic organic solvents and show some special advantages. Firstly, CO2 is inexpensive,nonflammable, nontoxic and chemical inert under many conditions. Secondly, scCO2 possesses hybrid properties of both liquid and gas, to the advantage of some reactions involving gaseous reagents. Control of the solvent density by variation of the temperature and pressure enables the solvent properties to be "tuned" to reactants. Finally, separating of CO2 from the reaction mixture is energy-efficient and simple. Here we disclose our new work on some organic reactions involving small molecules in scCO2.The results showed that the upper reactions in scCO2 could be carried out smoothly and thepressure of CO2 had a remarkable effect on the conversion and selectivity.

  13. Promising flame retardant textile in supercritical carbon dioxide

    Science.gov (United States)

    Since carbon dioxide is non-toxic, non-flammable and cost-effective, supercritical carbon dioxide (scCO2) is widely used in textile dyeing applications. Due to its environmentally benign character, scCO2 is considered in green chemistry as a substitute for organic solvents in chemical reactions. O...

  14. Cobalt carbonyl catalyzed olefin hydroformylation in supercritical carbon dioxide

    Science.gov (United States)

    Rathke, Jerome W.; Klingler, Robert J.

    1993-01-01

    A method of olefin hydroformylation is provided wherein an olefin reacts with a carbonyl catalyst and with reaction gases such as hydrogen and carbon monoxide in the presence of a supercritical reaction solvent, such as carbon dioxide. The invention provides higher yields of n-isomer product without the gas-liquid mixing rate limitation seen in conventional Oxo processes using liquid media.

  15. Synthesis pf dimethyl carbonate in supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Ballivet-Tkatchenko, D.; Plasseraud, L. [Universite de Bourgogne-UFR Sciences et Techniques, Dijon (France). Lab. de Synthese et Electrosynthese Organometalliques]. E-mail: ballivet@u-bourgogne.fr; Ligabue, R.A. [Pontificia Univ. Catolica do Rio Grande do Sul, Porto Alegre, RS (Brazil). Dept. de Quimica Pura

    2006-01-15

    The reactivity of carbon dioxide with methanol to form dimethyl carbonate was studied in the presence of the n-butylmethoxytin compounds n-Bu{sub 3}SnOCH{sub 3}, n-Bu{sub 2}Sn(OCH{sub 3}){sub 2}, and [n-Bu{sub 2}(CH{sub 3}O)Sn]{sub 2}O. The reaction occurred under solventless conditions at 423 K and was produced by an increase in CO{sub 2} pressure. This beneficial effect is primarily attributed to phase behavior. The mass transfer under liquid-vapor biphasic conditions was not limiting when the system reached the supercritical state for a CO{sub 2} pressure higher than 16 MPa. Under these conditions, CO{sub 2} acted as a reactant and a solvent. (author)

  16. Synthesis of dimethyl carbonate in supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    D. Ballivet-Tkatchenko

    2006-03-01

    Full Text Available The reactivity of carbon dioxide with methanol to form dimethyl carbonate was studied in the presence of the n-butylmethoxytin compounds n-Bu3SnOCH3, n-Bu2Sn(OCH32 , and [n-Bu2(CH3OSn]2 O. The reaction occurred under solventless conditions at 423 K and was produced by an increase in CO2 pressure. This beneficial effect is primarily attributed to phase behavior. The mass transfer under liquid-vapor biphasic conditions was not limiting when the system reached the supercritical state for a CO2 pressure higher than 16 MPa. Under these conditions, CO2 acted as a reactant and a solvent.

  17. Mini-Review:Green sustainable processes using supercritical fluid carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    RAMSEY Edward; SUN Qiubai; ZHANG Zhiqiang; ZHANG Chongmin; GOU Wei

    2009-01-01

    Environmentally benign carbon dioxide offers significant potential in its supercritical fluid phase to replace current reliance on a range of hazardous,relatively expensive and environmentally damaging organic solvents that are used on an extensive global basis.The unique combination of the physical properties of supercritical fluids are being exploited and further researched to continue the development and establishment of high efficiency,compact plant to provide energy and water efficient manufacturing processes.This mini-review is focused on the use and potential applications of supercritical fluid carbon dioxide for a selected range of key and emerging industrial processes as a sustainable alternative to totally eliminate or greatly reduce the requirement of numerous conventional organic solvents.Examples of the industries include:chemical extraction and purification,synthetic chemical reactions including polymerization and inorganic catalytic processes.Biochemical reactions involving enzymes,particle size engineering,textile dyeing and advanced material manufacture provide further illustrations of vital industrial activities where supercritical fluid technology processes are being implemented or developed.Some aspects relating to the economics of sustainable supercritical fluid carbon dioxide processes are also considered.

  18. Mini-review: green sustainable processes using supercritical fluid carbon dioxide.

    Science.gov (United States)

    Ramsey, Edward; Sun, Qiubai; Zhang, Zhiqiang; Zhang, Chongmin; Gou, Wei

    2009-01-01

    Environmentally benign carbon dioxide offers significant potential in its supercritical fluid phase to replace current reliance on a range of hazardous, relatively expensive and environmentally damaging organic solvents that are used on an extensive global basis. The unique combination of the physical properties of supercritical fluids are being exploited and further researched to continue the development and establishment of high efficiency, compact plant to provide energy and water efficient manufacturing processes. This mini-review is focused on the use and potential applications of supercritical fluid carbon dioxide for a selected range of key and emerging industrial processes as a sustainable alternative to totally eliminate or greatly reduce the requirement of numerous conventional organic solvents. Examples of the industries include: chemical extraction and purification, synthetic chemical reactions including polymerization and inorganic catalytic processes. Biochemical reactions involving enzymes, particle size engineering, textile dyeing and advanced material manufacture provide further illustrations of vital industrial activities where supercritical fluid technology processes are being implemented or developed. Some aspects relating to the economics of sustainable supercritical fluid carbon dioxide processes are also considered.

  19. Determination of binary diffusion coefficients in supercritical carbon dioxide with supercritical fluid chromatography (SFC)

    Energy Technology Data Exchange (ETDEWEB)

    Dahmen, N.; Duelberg, A.; Schneider, G.M. (Bochum Univ. (Germany, F.R.). Lehrstuhl fuer Physikalische Chemie 2)

    1990-03-01

    Binary diffusion coefficient D{sub 12} in supercritical carbon dioxide were determined in a Supercritical Fluid Chromatography (SFC) apparatus by the peak broadening method (PBM). Some cyclic and linear ketones were investigated as a function of pressure between 9.5 and 18 MPa at about 314 K corresponding to densities form 513 to 820 kg m{sup -3}. The resulting D{sub 12} values are of the order of 10{sup -8} m{sup 2} s{sup -1} and lnD{sub 12} decreases about linearly with increasing density {rho} of the CO{sub 2}. (orig.).

  20. Supercritical carbon dioxide-based sterilization of decellularized heart valves.

    Science.gov (United States)

    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

  1. Advanced Supercritical Carbon Dioxide Brayton Cycle Development

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Mark [Univ. of Wisconsin, Madison, WI (United States); Sienicki, James [Argonne National Lab. (ANL), Argonne, IL (United States); Moisseytsev, Anton [Argonne National Lab. (ANL), Argonne, IL (United States); Nellis, Gregory [Univ. of Wisconsin, Madison, WI (United States); Klein, Sanford [Univ. of Wisconsin, Madison, WI (United States)

    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 CO2 (S-CO2) 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-CO2 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

  2. Supercritical fluid technology for energy and environmental applications

    CERN Document Server

    Anikeev, Vladimir

    2014-01-01

    Supercritical Fluid Technology for Energy and Environmental Applications covers the fundamental principles involved in the preparation and characterization of supercritical fluids (SCFs) used in the energy production and other environmental applications. Energy production from diversified resources - including renewable materials - using clean processes can be accomplished using technologies like SCFs. This book is focused on critical issues scientists and engineers face in applying SCFs to energy production and environmental protection, the innovative solutions they have found, and the challenges they need to overcome. The book also covers the basics of sub- and supercritical fluids, like the thermodynamics of phase and chemical equilibria, mathematical modeling, and process calculations. A supercritical fluid is any substance at a temperature and pressure above its critical point where distinct liquid and gas phases do not exist. At this state the compound demonstrates unique properties, which can be "fine...

  3. Supercritical carbon dioxide: a solvent like no other

    Directory of Open Access Journals (Sweden)

    Jocelyn Peach

    2014-08-01

    Full Text Available Supercritical carbon dioxide (scCO2 could be one aspect of a significant and necessary movement towards green chemistry, being a potential replacement for volatile organic compounds (VOCs. Unfortunately, carbon dioxide has a notoriously poor solubilising power and is famously difficult to handle. This review examines attempts and breakthroughs in enhancing the physicochemical properties of carbon dioxide, focusing primarily on factors that impact solubility of polar and ionic species and attempts to enhance scCO2 viscosity.

  4. Preparation of drug delivery systems using supercritical fluid technology.

    Science.gov (United States)

    Kompella, U B; Koushik, K

    2001-01-01

    Small changes in temperature and pressure near the critical region induce dramatic changes in the density and solubility of supercritical fluids, thereby facilitating the use of environmentally benign agents such as CO2 for their solvent and antisolvent properties in processing a wide variety of materials. While supercritical fluid technologies have been in commercial use in the food and chromatography industries for several years, only recently has this technology made inroads in the formulation of drug delivery systems. This review summarizes some of the recent applications of supercritical fluid technology in the preparation of drug delivery systems. Drugs containing polymeric particles, plain drug particles, solute-containing liposomes, and inclusion complexes of drug and carrier have been formulated using this technology. Also, polymer separation using this technology is enabling the selection of a pure fraction of a polymer, thereby allowing a more precise control of drug release from polymeric delivery systems.

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

    Energy Technology Data Exchange (ETDEWEB)

    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 roadmap 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 features

  6. Solubilities of sub- and supercritical carbon dioxide in polyester resins

    NARCIS (Netherlands)

    Nalawade, SP; Picchioni, F; Janssen, LPBM; Patil, VE; Keurentjes, JTF; Staudt, R; Nalawade, Sameer P.; Patil, Vishal E.; Keurentjes, Jos T.F.

    In supercritical carbon dioxide (CO2) assisted polymer processes the solubility of CO2 in a polymer plays a vital role. The higher the amount of CO2 dissolved in a polymer the higher is the viscosity reduction of the polymer. Solubilities Of CO2 in polyester resins based on propoxylated bisphenol

  7. Stability of wheat germ oil obtained by supercritical carbon dioxide ...

    African Journals Online (AJOL)

    심정은

    with 1,3-regiospecific lipase at different temperatures (40 to 70°C) to produce diglycerides and ... Key words: Supercritical carbon dioxide, wheat germ oil, ethanolysis, .... Methanol (1 mL), replacing the extract, was used as the blank. The.

  8. Supercritical carbon dioxide process for pasteurization of fruit juices

    Science.gov (United States)

    Supercritical carbon dioxide (SCCO2) nonthermal processing inactivates microorganisms in juices using non-toxic and non-reactive CO2. However, data is lacking on the inactivation of E. coli K12 and L. plantarum in apple cider using pilot plant scale SCCO2 equipment. For this study, pasteurized pres...

  9. Extraction of heavy oil by supercritical carbon dioxide

    DEFF Research Database (Denmark)

    Rudyk, Svetlana Nikolayevna; Spirov, Pavel; Søgaard, Erik Gydesen

    2010-01-01

    The present study deals with the extraction of heavy oil by supercritical carbon dioxide at the pressure values changing from 16 to 56 MPa at the fixed value of temperature: 60oC. The amount of the recovered liquid phase of oil was calculated as a percentage of the extracted amount to the initial...

  10. Solubilities of ferrocene and acetylferrocene in supercritical carbon dioxide

    DEFF Research Database (Denmark)

    Kazemi, Somayeh; Belandria, Veronica; Janssen, Nico

    2012-01-01

    In this work, the solubilities of ferrocene and acetylferrocene in supercritical carbon dioxide (scCO2) were measured using an analytical method in a quasi-flow apparatus. High-performance liquid chromatography was applied through an online sampling procedure to determine the concentration...

  11. Green dyeing of cotton fabrics by supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    Zhang Juan

    2015-01-01

    Full Text Available Green dyeing process with zero waste water emission is a hot topic recently. This paper reveals that supercritical carbon dioxide is the best candidate for this purpose. Effects of thermodynamic parameters, such as enthalpy and entropy of activation, on dyeing process are studied experimentally.

  12. Solubilities of sub- and supercritical carbon dioxide in polyester resins

    NARCIS (Netherlands)

    Nalawade, SP; Picchioni, F; Janssen, LPBM; Patil, VE; Keurentjes, JTF; Staudt, R; Nalawade, Sameer P.; Patil, Vishal E.; Keurentjes, Jos T.F.

    2006-01-01

    In supercritical carbon dioxide (CO2) assisted polymer processes the solubility of CO2 in a polymer plays a vital role. The higher the amount of CO2 dissolved in a polymer the higher is the viscosity reduction of the polymer. Solubilities Of CO2 in polyester resins based on propoxylated bisphenol (P

  13. Aerobic Oxidation of Methyl Vinyl Ketone in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    OUYANG,Xiao-Yue(欧阳小月); JIANG,Huan-Feng(江焕峰); CHENG,Jin-Sheng(程金生); ZHANG,Qun-Jian(张群健)

    2002-01-01

    Aerobic oxidation of methyl vinyl ketone to acetal in supercritical carbon dioxide are achieved in high conversion and high selectivity when oxygen pressure reaches 0.5MPa. The effects of cocatalysts,additive, pressure and temperature of the reaction are studied in detail.

  14. Synthesis of fatty acid starch esters in supercritical carbon dioxide

    NARCIS (Netherlands)

    Muljana, Henky; van der Knoop, Sjoerd; Keijzer, Danielle; Picchioni, Francesco; Janssen, Leon P. B. M.; Heeres, Hero J.

    2010-01-01

    This manuscript describes an exploratory study on the synthesis of fatty acid/potato starch esters using supercritical carbon dioxide (scCO(2)) as the solvent. The effects of process variables such as pressure (6-25 MPa), temperature (120-150 degrees C) and various basic catalysts and fatty acid der

  15. Industrial applications and current trends in supercritical fluid technologies

    Directory of Open Access Journals (Sweden)

    Gamse Thomas

    2005-01-01

    Full Text Available Supercritical fluids have a great potential for wide fields of processes Although CO2 is still one of the most used supercritical gases, for special purposes propane or even fluorinated-chlorinated fluids have also been tested. The specific characteristics of supercritical fluids behaviour were analyzed such as for example the solubilities of different components and the phase equilibria between the solute and solvent. The application at industrial scale (decaffeinating of tea and coffee, hop extraction or removal of pesticides from rice, activity in supercritical extraction producing total extract from the raw material or different fractions by using the fractionated separation of beverages (rum, cognac, whisky, wine, beer cider, of citrus oils and of lipids (fish oils, tall oil were also discussed. The main interest is still for the extraction of natural raw materials producing food ingredients, nutraceuticals and phytopharmaceuticals but also cleaning purposes were tested such as the decontamination of soils the removal of residual solvents from pharmaceutical products, the extraction of flame retardants from electronic waste or precision degreasing and cleaning of mechanical and electronic parts. An increasing interest obviously exists for impregnation purposes based on supercritical fluids behaviour, as well as for the dying of fibres and textiles. The production of fine particles in the micron and submicron range, mainly for pharmaceutical products is another important application of supercritical fluids. Completely new products can be produced which is not possible under normal conditions. Supercritical fluid technology has always had to compete with the widespread opinion that these processes are very expensive due to very high investment costs in comparison with classical low-pressure equipment. Thus the opinion is that these processes should be restricted to high-added value products. A cost estimation for different plant sizes and

  16. Supercritical Carbon Dioxide Extraction of Benzene in Poly(vinyl acetate) and Polystyrene

    OpenAIRE

    佐々木, 正和; 滝嶌, 繁樹; 舛岡, 弘勝

    1989-01-01

    In order to test the applicability of the supercritical fluid extraction technique to the separation of impurities in polymers, separation of benzene from two polymers of poly(vinyl acetate) and polystyrene was carried out using supercritical carbon dioxide. Figure 1 shows a schematic diagram of the supercritical fluid extraction apparatus. It consists of the following sections: (1) compression of carbon dioxide, (2) extraction, and (3) control and measurement of carbon dioxide flow rates...

  17. Preparation of Aromatic Polycarbonate Nanoparticles using Supercritical Carbon Dioxide

    Science.gov (United States)

    Lee, Jun-Young; Song, Cheong-Hun; Kim, Joong-In; Kim, Jung-Hyun

    2002-04-01

    A novel synthetic process for producing aromatic polycarbonate (PC) nanoparticles using supercritical CO2 was developed. The objective of the present research work was to synthesize high molecular weight PC nanoparticles using transesterification between bisphenol-A (BPA) and diphenyl carbonate (DPC) in supercritical CO2 which is an excellent plasticizing agent and a good solvent for phenol, a by-product of the reaction. Poly(propylene oxide)-poly(ethylene oxide)-poly(propylene oxide) tri-block copolymer with CO2-phobic anchor and CO2-philic tail group was used as a stabilizer for the preparation of stable dispersions of BPA-DPC mixture in a CO2 continuous phase. As the reaction was proceeding, phenol formed from the reaction was dissolved and diffused into supercritical CO2 phase. The PC nanoparticles were isolated by simple venting of the supercritical CO2 from the reactor. Spherical morphology of PC particles was confirmed by scanning electron microscopy. Particle size and morphology of PC particles were modified upon variation of the process conditions. The resulting PC particles with a nano-size of 30-140 nm have a high molecular weight ( M w) of 3.1×105 (g/mol).

  18. Preparation and characterization of foxtail millet bran oil using subcritical propane and supercritical carbon dioxide extraction

    National Research Council Canada - National Science Library

    Shi, Yuzhong; Ma, Yuxiang; Zhang, Ruitin; Ma, Hanjun; Liu, Benguo

    2015-01-01

    ...), supercritical carbon dioxide extraction (SCE) and subcritical propane extraction (SPE) and analyzed the yield, physicochemical property, fatty acid profile, tocopherol composition, oil oxidative stability in this study...

  19. Fractionation for Biodiesel Purification Using Supercritical Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Chao-Yi Wei

    2014-02-01

    Full Text Available In recent years, biodegradable and alternative biodiesel has attracted increased attention worldwide. Producing biodiesel from biomass involves critical separation and purification technology. Conventional technologies such as gravitational settling, decantation, filtration, water washing, acid washing, organic solvent washing and absorbent applications are inefficient, less cost effective and environmentally less friendly. In this study supercritical carbon dioxide (SC-CO2 with few steps and a low environmental impact, was used for biodiesel fractionation from impure fatty acid methyl ester (FAME solution mixes. The method is suitable for application in a variety of biodiesel production processes requiring subsequent stages of purification. The fractionation and purification was carried out using continuous SC-CO2 fractionation equipment, consisting of three columns filled with stainless steel fragments. A 41.85% FAME content solution mix was used as the raw material in this study. Variables were a temperature range of 40–70 °C, pressure range of 10–30 MPa, SC-CO2 flow rate range of 7–21 mL/min and a retention time range of 30–90 min. The Taguchi method was used to identify optimal operating conditions. The results show that a separated FAME content of 99.94% was verified by GC-FID under optimal fractionation conditions, which are a temperature of 40 °C of, a pressure level of 30MPa and a flow rate of 7 mL/min of SC-CO2 for a retention time of 90 min.

  20. Treating of cement during with supercritical fluid carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Min; Shin, Tae Wook; Whang, Jooho; Park Kwan Heun [Department of Nuclear Engineering, Kyunghee University, Yongin (Korea, Republic of)

    1999-07-01

    The main curing reactions of a portland cement are the formation of portlandite, Ca(OH){sub 2}, and calcium silicate hydrates, CSH. In nature, the cement extracts CO{sub 2} from air and convert the calcium hydroxide and CSH to calcium carbonate(CaCO{sub 3}), calcite. This process forms chemically stable and mechanically enhanced cement. By exposing an OPC to supercritical CO{sub 2}(SCCO2), the carbonate reaction was greatly accelerated. XRD analysis of compressive strength showed the mechanical enhancement.

  1. Birch Bark Dry Extract by Supercritical Fluid Technology: Extract Characterisation and Use for Stabilisation of Semisolid Systems

    Directory of Open Access Journals (Sweden)

    Markus Armbruster

    2017-03-01

    Full Text Available Triterpene compounds like betulin, betulinic acid, erythrodiol, oleanolic acid and lupeol are known for many pharmacological effects. All these substances are found in the outer bark of birch. Apart from its pharmacological effects, birch bark extract can be used to stabilise semisolid systems. Normally, birch bark extract is produced for this purpose by extraction with organic solvents. Employing supercritical fluid technology, our aim was to develop a birch bark dry extract suitable for stabilisation of lipophilic gels with improved properties while avoiding the use of toxic solvents. With supercritical carbon dioxide, three different particle formation methods from supercritical solutions have been tested. First, particle deposition was performed from a supercritical solution in an expansion chamber. Second, the Rapid Expansion of Supercritical Solutions (RESS method was used for particle generation. Third, a modified RESS-procedure, forming the particles directly into the thereby gelated liquid, was developed. All three methods gave yields from 1% to 5.8%, depending on the techniques employed. The triterpene composition of the three extracts was comparable: all three gave more stable oleogels compared to the use of an extract obtained by organic solvent extraction. Characterizing the rheological behaviour of these gels, a faster gelling effect was seen together with a lower concentration of the extract required for the gel formation with the supercritical fluid (SCF-extracts. This confirms the superiority of the supercritical fluid produced extracts with regard to the oleogel forming properties.

  2. Solubility of the sesquiterpene alcohol patchoulol in supercritical carbon dioxide.

    Science.gov (United States)

    Hybertson, Brooks M

    2007-01-01

    The solubility of the sesquiterpene alcohol patchoulol in supercritical carbon dioxide was measured at P ranging from 10.0 MPa to 25.0 MPa and T of 40.0 and 50.0 °C using a simple microsampling type apparatus with a 100.5 µL sample loop to remove aliquots for off-line analysis. The system was first validated using vanillin with off-line spectrophotometric analysis, then utilized for patchoulol measurements with off-line GC-MS analysis. The measured solubility of patchoulol in supercritical CO(2) ranged from mole fractions of 0.43 × 10(-3) at 10.0 MPa and 50.0 °C to 9.45 × 10(-3) at 25.0 MPa and 40.0 °C.

  3. A supercritical oxidation system for the determination of carbon isotope ratios in marine dissolved organic carbon

    NARCIS (Netherlands)

    Le Clercq, Martijn; Van der Plicht, Johannes; Meijer, Harro A.J.

    1998-01-01

    An analytical oxidation system employing supercritical oxidation has been developed. It is designed to measure concentration and the natural carbon isotope ratios (C-13, C-14) Of dissolved organic carbon (DOC) and is especially suited for marine samples. The oxidation takes place in a ceramic tube a

  4. Palladium-Catalyzed Carbonylation of Primary Amines in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    李金恒; 江焕峰; 陈鸣才

    2001-01-01

    The chemoselectity of the palladimm-catalyzed carbonylation of amines was affected by the addition of MeOH in supercritical carbon dioxide. The results show different selectivity in supercritical carbon dioxide CO2(sc) from that in alcohol.Methyl carbamate and its derivatives were obtained in high yields in CO2(sc).

  5. Metal Ions Extraction with Glucose Derivatives as Chelating Reagents in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    Guo Chen YANG; Hai Jian YANG

    2006-01-01

    A series of glucose derivatives have been used as chelating reagents to extract metal ions in supercritical carbon dioxide. With perfluoro-1-octanesulfonic acid tetraethylammonium salt as additive, glucose derivatives were selective for Sr2+ and Pb2+ extraction in supercritical carbon dioxide.

  6. 超临界 CO2萃取废弃油基钻屑的实验研究%Experimental study on waste oil-based drilling cuttings by utilizing supercritical carbon dioxide extraction technology

    Institute of Scientific and Technical Information of China (English)

    李赵; 杜国勇; 朱盟翔; 杨露; 涂雯雯

    2016-01-01

    In this paper ,supercritical carbon dioxide was used as an extracting agent to recovery the oil from the oil‐based drilling cuttings .By setting the residual oil contents as the main evaluation index , the effect of several factors including extracting pressure , extracting temperature , and extracting time were investigated .The results showed that the residual oil content was 0 .748% when the extracting pressure was 25 MPa ,the extracting temperature was 50 ℃ ,and the extracting time was 100 min .This extraction technology shows a favorable treatment efficiency .%采用超临界CO2为萃取剂,以萃取后油基钻屑的残油率为主要评价指标,研究了不同萃取条件(萃取压力、萃取温度、萃取时间)对废弃油基钻屑萃取的影响。实验结果表明,当萃取温度为50℃、萃取时间为100 m in、萃取压力为25 M Pa时,残油率为0.748%,此萃取工艺展现出了良好的处理效果。

  7. Histidine-catalyzed synthesis of cyclic carbonates in supercritical carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The coupling reaction of carbon dioxide with epoxides was investigated using naturally occurring α-amino acids as the catalyst in supercritical carbon dioxide and it was found that L-histidine is the most active catalyst.In the presence of 0.8 mol% of L-histidine at 130°C under 8 MPa of CO2,the reaction of carbon dioxide with epoxides proceeded smoothly,affording corresponding cyclic carbonates in good to excellent yields.

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

    Energy Technology Data Exchange (ETDEWEB)

    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 the 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.

  9. Forsterite Carbonation in Wet Supercritical CO2 and Sodium Citrate

    Science.gov (United States)

    Qiu, L.; Schaef, T.; Wang, Z.; Miller, Q.; McGrail, P.

    2013-12-01

    Lin Qiu1*, Herbert T. Schaef2, Zhengrong Wang1, Quin R.S. Miller3, BP McGrail2 1. Yale University, New Haven, CT, USA 2. Pacific Northwest National Laboratory, Richland, WA, USA 3. University of Wyoming, Laramie, WY, USA Geologic reservoirs for managing carbon emissions (mostly CO2) have expanded over the last 5 years to include unconventional formations including basalts and fractured shales. Recently, ~1000 metric tons of CO2 was injected into the Columbia River Basalt (CRB) in Eastern Washington as part of the Wallula Pilot Project, Big Sky Regional Carbon Partnership. Based on reservoir conditions, the injected CO2 is present as a supercritical fluid that dissolves into the formation water over time, and reacts with basalt components to form carbonate minerals. In this paper, we discuss mineral transformation reactions occurring when the forsterite (Mg2SiO4) is exposed to wet scCO2 in equilibrium with pure water and sodium citrate solutions. Forsterite was selected as it is an important olivine group mineral present in igneous and mafic rocks. Citrate was selected as it has been shown to enhance mineral dissolution and organic ligands are possible degradation products of the microbial communities present in the formational waters of the CRB. For the supercritical phase, transformation reactions were examined by in situ high pressure x-ray diffraction (HXRD) in the presence of supercritical carbon dioxide (scCO2) in contact with water and sodium citrate solutions at conditions relevant to carbon sequestration. Experimental results show close-to-complete dissolution of forsterite in contact with scCO2 equilibrated with pure water for 90 hours (90 bar and 50°C). Under these conditions, thin films of water coated the mineral surface, providing a mechanism for silicate dissolution and transport of cations necessary for carbonate formation. The primary crystalline component initially detected with in situ HXRD was the hydrated magnesium carbonate, nesquehonite [Mg

  10. Solubilities of some hydroxyxanthone derivatives in supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Ghiasvand, A.R.; Hosseini, M.; Sharghi, H.; Yamini, Y.; Shamsipur, M.

    1999-12-01

    The equilibrium solubilities of four hydroxyxanthone derivatives have been measured in supercritical carbon dioxide using a simple and reliable static method. The measurements were performed in the pressure range 74.0--354.6 bar at the temperatures 32, 45, 55, 65, and 75 C. The order of solubility observed for the compounds used was discussed in terms of their possible intra- and intermolecular H-bonds and polarities. The measured solubilities were correlated using a semiempirical model. The calculated results show satisfactory agreement with the experimental data.

  11. Supercritical fluids as a green technology for the pretreatment of lignocellulosic biomass.

    Science.gov (United States)

    Daza Serna, L V; Orrego Alzate, C E; Cardona Alzate, C A

    2016-01-01

    One of the main drawbacks for using lignocellulosic biomass is related to its recalcitrance. The pretreatment of lignocellulosic biomass plays an important role for delignification and crystallinity reduction purposes. In this work rice husk (RH) was submitted to supercritical pretreatment at 80°C and 270 bar with the aim to determine the effect on lignin content, crystallinity as well as enzymatic digestibility. The yields obtained were compared with dilute sulfuric acid pretreatment as base case. Additionally a techno-economic and environmental comparison of the both pretreatment technologies was performed. The results show a lignin content reduction up to 90.6% for the sample with 75% moisture content using a water-ethanol mixture. The results for crystallinity and enzymatic digestibility demonstrated that no reductions were reached. Supercritical pretreatment presents the best economical and environmental performance considering the solvents and carbon dioxide recycling.

  12. Supercritical CO2-driven,periodic patterning on one-dimensionals carbon nanomaterials

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    One-dimensional carbon nano-materials,in particular carbon nanotubes (CNTs) and carbon nanofibers (CNFs),are of scientific and technological interest due to their satisfactory properties and ability to serve as templates for directed assembly.In this work,linear high density polyethylene (PE) was periodically decorated on CNTs and CNFs using a supercritical carbon dioxide (scCO2)antisolvent-induced polymer epitaxy (SAIPE) method,leading to nano-hybrid shish-kebab (NHSK) structures.The formation mechanism of different morphologies of PE lamellae on CNTs and CNFs has been discussed.Palladium nanoparticles were synthesized and immobilized on the PE/CNF NHSK structure with the assistance of scCO2.The obtained hierarchical nano-hybrid architecture may find applications in microfabrication and other related fields.

  13. Characteristics modeling for supercritical circulating fluidized bed boiler working in oxy-combustion technology

    Science.gov (United States)

    Balicki, Adrian; Bartela, Łukasz

    2014-06-01

    Among the technologies which allow to reduce greenhouse gas emission, mainly carbon dioxide, special attention deserves the idea of `zeroemission' technology based on boilers working in oxy-combustion technology. In the paper the results of analyses of the influence of changing two quantities, namely oxygen share in oxidant produced in the air separation unit, and oxygen share in oxidant supplied to the furnace chamber on the selected characteristics of a steam boiler including the degree of exhaust gas recirculation, boiler efficiency and adiabatic flame temperature, was examined. Due to the possibility of the integration of boiler model with carbon dioxide capture, separation and storage installation, the subject of the analysis was also to determine composition of the flue gas at the outlet of a moisture condensation installation. Required calculations were made using a model of a supercritical circulating fluidized bed boiler working in oxy-combustion technology, which was built in a commercial software and in-house codes.

  14. Supercritical fluid attachment of palladium nanoparticles on aligned carbon nanotubes.

    Science.gov (United States)

    Ye, Xiang-Rong; Lin, Yuehe; Wai, Chien M; Talbot, Jan B; Jin, Sungho

    2005-06-01

    Nanocomposite materials consisting of Pd nanoparticles deposited on aligned multi-walled carbon nanotubes have been fabricated through hydrogen reduction of palladium-beta-diketone precursor in supercritical carbon dioxide. The supercritical fluid processing allowed deposition of high-density Pd nanoparticles (approximately 5-10 nm) on both as-grown (unfunctionalized) and functionalized (using HNO3 oxidation) nanotubes. However, the wet processing for functionalization results in pre-agglomerated, bundle-shaped nanotubes, thus significantly reducing the effective surface area for Pd particle deposition, although the bundling provides more secure, lock-in-place positioning of nanotubes and Pd catalyst particles. The nanotube bundling is substantially mitigated by Pd nanoparticle deposition on the unfunctionalized and geometrically separated nanotubes, which provides much higher catalyst surface area. Such nanocomposite materials utilizing geometrically secured and aligned nanotubes can be useful for providing much enhanced catalytic activities to chemical and electrochemical reactions (e.g., fuel cell reactions), and eliminate the need for tedious catalyst recovery process after the reaction is completed.

  15. Synthesis of biodiesel from edible and non-edible oils in supercritical alcohols and enzymatic synthesis in supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Vivek Rathore; Giridhar Madras [Indian Institute of Science, Bangalore (India). Department of Chemical Engineering

    2007-12-15

    Biodiesel is an attractive alternative fuel because it is environmentally friendly and can be synthesized from edible and non-edible oils. The synthesis of biodiesel from edible oils like palm oil and groundnut oil and from crude non-edible oils like Pongamia pinnata and Jatropha curcas was investigated in supercritical methanol and ethanol without using any catalyst from 200 to 400{sup o}C at 200 bar. The variables affecting the conversion during transesterification, such as molar ratio of alcohol to oil, temperature and time were investigated in supercritical methanol and ethanol. Biodiesel was also synthesized enzymatically with Novozym-435 lipase in presence of supercritical carbon dioxide. The effect of reaction variables such as temperature, molar ratio, enzyme loading and kinetics of the reaction was investigated for enzymatic synthesis in supercritical carbon dioxide. Very high conversions (>80%) were obtained within 10 min and nearly complete conversions were obtained at within 40 min for the synthesis of biodiesel in supercritical alcohols. However, conversions of only 60-70% were obtained in the enzymatic synthesis even after 8 h. 48 refs., 8 figs., 1 tab.

  16. Applications of supercritical fluid technology to pollution prevention and waste minimization

    Energy Technology Data Exchange (ETDEWEB)

    Turner, R.J. [Environmental Protection Agency, Cincinnati, OH (United States)

    1995-10-01

    One approach to the prevention of pollution and the reduction of worker exposure from conventional solvents is the use of less hazardous substitutes. One of the more novel substitutes is carbon dioxide. Although carbon dioxide is a gas at ordinary conditions, it can be liquified by application of pressure. In its supercritical state, it exhibits good solvent properties. Separation of the carbon dioxide from the extracted materials can be accomplished by pressure reduction, adsorption onto activated carbon, or with a membrane process, e.g., decaffeination of coffee. This paper presents a brief overview of the university and federal laboratory collaborative efforts focusing on processes using supercritical carbon dioxide as a substitute for hazardous solvents. The SCCO2 technology applications under this program include extraction of natural pharmaceutical materials, phase-transfer catalysis, solvent replacement in chemical synthesis, temperature-solubility relationships, and separation of organic materials from soils and slurries. A paper on the extraction of heavy metals with SCCO2 was presented by Ataai et.al. at the 87th National Meeting, A&WMA. This work is also supported by the EPA.

  17. Improved manometric setup for the accurate determination of supercritical carbon dioxide sorption

    NARCIS (Netherlands)

    Van Hemert, P.; Bruining, H.; Rudolph, E.S.J.; Wolf, K.H.A.A.; Maas, J.G.

    2009-01-01

    An improved version of the manometric apparatus and its procedures for measuring excess sorption of supercritical carbon dioxide are presented in detail with a comprehensive error analysis. An improved manometric apparatus is necessary for accurate excess sorption measurements with supercritical car

  18. Improved manometric setup for the accurate determination of supercritical carbon dioxide sorption

    NARCIS (Netherlands)

    Van Hemert, P.; Bruining, H.; Rudolph, E.S.J.; Wolf, K.H.A.A.; Maas, J.G.

    2009-01-01

    An improved version of the manometric apparatus and its procedures for measuring excess sorption of supercritical carbon dioxide are presented in detail with a comprehensive error analysis. An improved manometric apparatus is necessary for accurate excess sorption measurements with supercritical car

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

    Science.gov (United States)

    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.

  20. CFD Analysis of a supercritical carbon dioxide compressor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Gu; Lee, Jeong Ik; Ahn, Yoon Han; Lee, Jek Young; Cha, Jae Eun; Addad, Yacine [KAIST, Daejeon (Korea, Republic of)

    2012-10-15

    The supercritical carbon dioxide Brayton cycle is considered as an attractive cycle for the next generation nuclear systems. It was identified that the compressor can achieve very small compressing work as operating conditions become closer to the critical point. Smaller amount of input work contributes to the enhancement of overall net cycle efficiency. Comparing to traditional water vapor cycle and helium cycle, the S CO{sup 2} cycle has relatively much less volume and component size. Therefore, S CO{sup 2} cycle can be used for many purposes such as nuclear ship propulsion where volume requirement is strict, or a small nuclear reactor when it is constructed on geographically limited area One of the main factors for determining the supercritical Brayton cycle efficiency is the performance of turbomachineries. Many research organizations already obtained experimental data of S CO{sup 2} cycle turbomachineries, but the amount of data is still limited. Our research team is conducting a S CO{sup 2} compressor test to obtain fundamental data for advanced compressor design and measure the performance of the compressor near the critical point. The S CO{sup 2} compressor testing loop is specially designed to test main compressor of the loop. The S CO{sup 2} fluid shows the properties of gases and liquids at the same time, but its behavior is closer to the liquid rather than gas near the critical point. Therefore, we are performing compressor test with canned motor pump which is unique from other previous studies.

  1. Palladium-Catalyzed Addition of Carbon Monoxide and Carbon Tetrachloride to 1-Octene in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    张群健; 孙均华; 江焕峰; 欧阳小月; 程金生

    2003-01-01

    The Pd-catalyzed addition of carbon monoxide and carbon tetrachloride to 1-octene gave coadduct [alkyl 2-( 2, 2, 2-trichloroethyl)octanoate] as the major product in supercritical carbon dioxide by using pyridine as the base. It was found that the selectivity and the yield of coadduct were greatly affected by the pressure of carbon dioxide, the reaction temperature and the amounts of alcohol and base used.

  2. Synthesis and Characterization of Cobalt-Carbon Core-Shell Microspheres in Supercritical Carbon Dioxide System

    Institute of Scientific and Technical Information of China (English)

    Jun-song Yang; Qian-wang Chen

    2008-01-01

    The synthesis of cobalt-carbon core-shell microspheres in supercritical carbon dioxide system was investigated. Cobalt-carbon core-shell microspheres with diameter of about 1μm were prepared at 350℃ for 12 h in a closed vessel containing an appropriate amount of bis(cyclopentadienyl)cobalt powder and dry ice.Characterization by a variety of techniques,including X-ray powder diffraction,X-ray photoelectron spectroscopy,Transmission electron microscope,Fourier transform infrared spectrum and Raman spectroscopy analysis reveals that each cobalt-carbon core-shell microsphere is made up of an amorphous cobalt core with diameter less than 1 μm and an amorphous carbon shell with thickness of about 200 nm.The possible growth mechanism of cobalt-carbon core-shell microspheres is discussed,based on the pyrolysis of bis(cyclopentadienyl)cobalt in supercritical carbon dioxide and the deposition of carbon or carbon clusters with odd electrons on the surface of magnetic cobalt cores due to magnetic attraction.Magnetic measurements show 141.41 emu/g of saturation magnetization of a typical sample,which is lower than the 168 emu/g of the corresponding metal cobalt bulk material.This is attributed to the considerable mass of the carbon shell and amorphous nature of the magnetic core.Control of magnetism in the cobalt-carbon core-shell microspheres was achieved by annealing treatments.

  3. Supercritical carbon dioxide extraction of Mentha pulegium L. essential oil.

    Science.gov (United States)

    Aghel, Nasrin; Yamini, Yadollah; Hadjiakhoondi, Abbas; Pourmortazavi, Seied Mahdi

    2004-02-06

    The dependence of Mentha pulegium L. (pennyroyal) essential oil composition, obtained by supercritical carbon dioxide (SC-CO(2)), with the following parameters: pressure, temperature, extraction time (dynamic), and modifier (methanol) was studied. The results were also compared with those obtained by conventional hydrodistillation method in laboratory conditions. Regarding the percentages of menthone (30.3%) and pulegone (52.0%), the optimum SFE results were obtained at the following experimental conditions: pressure=100atm, T=35 degrees C, dynamic time=10min, and V(modifier)=0mul. The results of hydrodistillation showed that the major components of M. pulegium L. were pulegone (37.8%), menthone (20.3%), and piperitenone (6.8%). The evaluation of the composition of each extract was performed by gas chromatography-mass spectrometry.

  4. Extraction of Genistein from Sophora flavescens with Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Han, Chang-Nam; Kang, Choon-Hyoung [Chonnam National University, Gwangju (Korea, Republic of)

    2015-08-15

    This study was directed to finding an optimum extraction condition of genistein from the S. flavescens with supercritical carbon dioxide as a solvent. In this effort, effects of the extraction conditions including pressure, temperature and a co-solvent on the extraction efficiency were investigated. The aqueous ethanol and methanol solutions were used as co-solvents while the tested operating pressure and temperature ranges were from 200 bar to 300 bar and from 308.15 K to 323.15 K, respectively. The concentration of genistein was determined by means of HPLC equipped with a UV detector. From the results, it was observed that an increase in pressure led to the higher extraction efficiency. Further, methanol showed better performance as a co-solvent than ethanol. The DPPH radical scavenging activities were measured to compare antioxidant activities of S. flavescens extracts.

  5. Selective hydrogenation of phenol in supercritical carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    ZOU Gang; JIANG Huan-feng; ZHAO Yah; YIN Ji-xiang; SHI Chao-feng

    2004-01-01

    Liquid phase hydrogenation of phenol over Pt/C catalysts was investigated under conventional conditions and supercritical carbon dioxide (scCO2). The equivalent ration of hydrogen to phenol shows a significant effect on the product selectivity. Hydrogenation of phenol in different solvents was also studied, the experimental results show that polarity of solvents influences the yield of cyclohexanone remarkably, scCO2 has the highest one. Catalytic hydrogenation of phenol in scCO2 or sub-scCO2 was emphatically researched. The result is that near the critical point of CO2 phenol has higher reaction activity than that of normal organic solvents, cyclohexanone has 47% in yield and 87% in selectivity.

  6. Catalytic Formation of Propylene Carbonate from Supercritical Carbon Dioxide/Propylene Oxide Mixture

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Propylene carbonate was synthesized from supercritical carbon dioxide (SC-CO2)/ propylene oxide mixture with phthalocyaninatoaluminium chloride (ClAlPc)/ tetrabutylammon-ium bromide (n-Bu4NBr) as catalyst. The high rate of reaction was attributed to rapid diffusion and the high miscibility of propylene oxide in SC-CO2 under employed conditions. Various reaction periods present different formation rate of propylene carbonate, mainly due to the existence of phase change during the reaction. The experimental results demonstrate that SC-CO2 could be used as not only an environmentally benign solvent but also a carbon precursor in synthesis.

  7. Experimental study on heat transfer characteristics of supercritical carbon dioxide in horizontal tube

    Institute of Scientific and Technical Information of China (English)

    Jing LV; Meng FU; Na QIN; Bin DONG

    2008-01-01

    The heat transfer characteristics of supercrit-ical carbon dioxide in a horizontal tube with water in the vertical cross flow form were experimentally investi-gated. The results indicate that the changes of inlet pres-sure, mass flow rate, and cooling water flow rate have major effects on heat transfer performance. The varia-tions of Reynolds number and Prandtl number were obtained in counter flow and vertical cross flow. The four conventional correlations for convection heat transfer of supercritical carbon dioxide were verified by the experi-mental data in this study and the correlation agree with this experimental condition was determined.

  8. SUPERCRITICAL FLUID TECHNOLOGY: NASCENT CONTRIVANCE FOR PHARMACEUTICAL PRODUCT DEVELOPMENT

    Directory of Open Access Journals (Sweden)

    B.S. Wakure*, A.V. Yadav , N.M. Bhatia and M.A. Salunke

    2012-07-01

    Full Text Available A supercritical fluid (SF can be defined as a dense non condensable fluid. A fluid reaches the supercritical status when its temperature and pressure exceed the relevant critical temperature and pressure. At the critical point only a single phase exists which has some properties typical of liquids (density and some of gases (viscosity, compressibility, and mass diffusion coefficient. For pharmaceutical applications, the most widely used SF is carbon dioxide (more than 98% of the applications have been developed using this fluid because of its low and easily accessible critical temperature (31.2◦C and pressure (7.4MPa, non-flammability, non-toxicity and inexpensiveness. The physical and thermal properties of SCFs fall between those of the pure liquid and gas. SCFs offer liquid-like densities, gas-like viscosities, gas-like compressibility properties and higher diffusivities than liquids. The properties of SCFs, such as polarity, viscosity, and diffusivity, can be altered several-fold by varying the operating temperature and/or pressure during the process. This flexibility is enabling the use of SCFs for various applications in the food and pharmaceutical industries, with the drug delivery system design being a more recent addition.

  9. Evidence for Carbonate Surface Complexation during Forsterite Carbonation in Wet Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Loring, John S.; Chen, Jeffrey; Benezeth Ep Gisquet, Pascale; Qafoku, Odeta; Ilton, Eugene S.; Washton, Nancy M.; Thompson, Christopher J.; Martin, Paul F.; McGrail, B. Peter; Rosso, Kevin M.; Felmy, Andrew R.; Schaef, Herbert T.

    2015-07-14

    Continental flood basalts are attractive formations for geologic sequestration of carbon dioxide because of their reactive divalent-cation containing silicates, such as forsterite (Mg2SiO4), suitable for long-term trapping of CO2 mineralized as metal carbonates. The goal of this study was to investigate at a molecular level the carbonation products formed during the reaction of forsterite with supercritical CO2 (scCO2) as a function of the concentration of H2O adsorbed to the forsterite surface. Experiments were performed at 50 °C and 90 bar using an in situ IR titration capability, and post-reaction samples were examined by ex situ techniques, including SEM, XPS, FIB-TEM, TGA-MS, and MAS-NMR. Carbonation products and reaction extents varied greatly with adsorbed H2O. We show for the first time evidence of Mg-carbonate surface complexation under wet scCO2 conditions. Carbonate is found to be coordinated to Mg at the forsterite surface in a predominately bidentate fashion at adsorbed H2O concentrations below 27 µmol/m2. Above this concentration and up to 76 µmol/m2, monodentate coordinated complexes become dominant. Beyond a threshold adsorbed H2O concentration of 76 µmol/m2, crystalline carbonates continuously precipitate as magnesite, and the particles that form are hundreds of times larger than the estimated thicknesses of the adsorbed water films of about 7 to 15 Å. At an applied level, these results suggest that mineral carbonation in scCO2 dominated fluids near the wellbore and adjacent to caprocks will be insignificant and limited to surface complexation, unless adsorbed H2O concentrations are high enough to promote crystalline carbonate formation. At a fundamental level, the surface complexes and their dependence on adsorbed H2O concentration give insights regarding forsterite dissolution processes and magnesite nucleation and growth.

  10. Silicate Carbonation Processes in Water-Bearing Supercritical CO2 Fluids: Implications for Geologic Carbon Sequestration

    Science.gov (United States)

    Miller, Q. R.; Schaef, T.; Thompson, C.; Loring, J. S.; Windisch, C. F.; Bowden, M. E.; Arey, B. W.; McGrail, P.

    2012-12-01

    Global climate change is viewed by many as an anthropogenic phenomenon that could be mitigated through a combination of conservation efforts, alternative energy sources, and the development of technologies capable of reducing carbon dioxide (CO2) emissions. Continued increases of atmospheric CO2 concentrations are projected over the next decade, due to developing nations and growing populations. One economically favorable option for managing CO2 involves subsurface storage in deep basalt formations. The silicate minerals and glassy mesostasis basalt components act as metal cation sources, reacting with the CO2 to form carbonate minerals. Most prior work on mineral reactivity in geologic carbon sequestration settings involves only aqueous dominated reactions. However, in most sequestration scenarios, injected CO2 will reside as a buoyant fluid in contact with the sealing formation (caprock) and slowly become water bearing. Comparatively little laboratory research has been conducted on reactions occurring between minerals in the host rock and the wet scCO2. In this work, we studied the carbonation of wollastonite [CaSiO3] exposed to variably wet supercritical CO2 (scCO2) at a range of temperatures (50, 55 and 70 °C) and pressures (90,120 and 160 bar) in order to gain insight into reaction processes. Mineral transformation reactions were followed by two novel in situ high pressure techniques, including x-ray diffraction that tracked the rate and extents of wollastonite conversion to calcite. Increased dissolved water concentrations in the scCO2 resulted in increased carbonation approaching ~50 wt. %. Development of thin water films on the mineral surface were directly observed with infrared (IR) spectroscopy and indirectly with 18O isotopic labeling techniques (Raman spectroscopy). The thin water films were determined to be critical for facilitating carbonation processes in wet scCO2. Even in extreme low water conditions, the IR technique detected the formation of

  11. Preparation of Dispersed Platinum Nanoparticles on a Carbon Nanostructured Surface Using Supercritical Fluid Chemical Deposition

    Directory of Open Access Journals (Sweden)

    Mineo Hiramatsu

    2010-03-01

    Full Text Available We have developed a method of forming platinum (Pt nanoparticles using a metal organic chemical fluid deposition (MOCFD process employing a supercritical fluid (SCF, and have demonstrated the synthesis of dispersed Pt nanoparticles on the surfaces of carbon nanowalls (CNWs, two-dimensional carbon nanostructures, and carbon nanotubes (CNTs. By using SCF-MOCFD with supercritical carbon dioxide as a solvent of metal-organic compounds, highly dispersed Pt nanoparticles of 2 nm diameter were deposited on the entire surface of CNWs and CNTs. The SCF-MOCFD process proved to be effective for the synthesis of Pt nanoparticles on the entire surface of intricate carbon nanostructures with narrow interspaces.

  12. Evidence for Carbonate Surface Complexation during Forsterite Carbonation in Wet Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Loring, John S.; Chen, Jeffrey; Benezeth, Pascale; Qafoku, Odeta; Ilton, Eugene S.; Washton, Nancy M.; Thompson, Christopher J.; Martin, Paul F.; McGrail, B. Peter; Rosso, Kevin M.; Felmy, Andrew R.; Schaef, Herbert T.

    2015-06-16

    Continental flood basalts are attractive formations for geologic sequestration of carbon dioxide because of their reactive divalent-cation containing silicates, such as forsterite (Mg2SiO4), suitable for long-term trapping of CO2 mineralized as metal carbonates. The goal of this study was to investigate at a molecular level the carbonation products formed during the reaction of forsterite with supercritical CO2 (scCO2) as a function of the concentration of H2O adsorbed to the forsterite surface. Experiments were performed at 50 °C and 90 bar using an in situ IR titration capability, and post-reaction samples were examined by ex situ techniques, including SEM, XPS, FIB-TEM, TGA-MS, and MAS-NMR. Carbonation products and reaction extents varied greatly with adsorbed H2O. We show for the first time evidence of Mg-carbonate surface complexation under wet scCO2 conditions. Carbonate is found to be coordinated to Mg at the forsterite surface in a predominately bidentate fashion at adsorbed H2O concentrations below 27 µmol/m2. Above this concentration and up to 76 µmol/m2, monodentate coordinated complexes become dominant. Beyond a threshold adsorbed H2O concentration of 76 µmol/m2, crystalline carbonates continuously precipitate as magnesite, and the particles that form are hundreds of times larger than the estimated thicknesses of the adsorbed water films of about 7 to 15 Å. At an applied level, the implication of these results is that mineral trapping in scCO2 dominated fluids will be insignificant and limited to surface complexation unless adsorbed H2O concentrations are high enough to promote crystalline carbonate formation. At a fundamental level, the surface complexes and their dependence on adsorbed H2O concentration give insights regarding forsterite dissolution processes and magnesite nucleation and growth.

  13. Nanoparticles in the pharmaceutical industry and the use of supercritical fluid technologies for nanoparticle production.

    Science.gov (United States)

    Sheth, Pratik; Sandhu, Harpreet; Singhal, Dharmendra; Malick, Waseem; Shah, Navnit; Kislalioglu, M Serpil

    2012-05-01

    is limited. Carbon dioxide, which is the only supercritical fluid that is preferentially used in pharmaceutical processes, is not a good solvent for many Active Pharmaceutical Ingredients (API). Various researchers have modified the RESS process to overcome its solubilizing limitations, by introducing RESOLV, RESAS, and RESS-SC. Overall, all RESS based processes are difficult to scale up. The SAS processes are based on decreasing the solvent power of a polar organic solvent in which the substrate (API & polymer of interest) is dissolved, by saturating it with carbon dioxide (CO2) at supercritical conditions. CO2 causes precipitation and recrystalization of the drug. SAS is scalable and can be applied to a wide variety of APIs and polymers. Minor modifications of basic SAS process include GAS, ASES, SAS-DEM and SAS-EM. Processes where SCF is used as an anti solvent and dispersing agent include SEDS, SAA, and A-SAIS. The mechanisms and applications of these processes were briefly discussed. In PGSS, CO2 is dissolved in organic solutions or melted compounds and it is successfully used for manufacturing drug products as well as for drying purposes. The two widely used methods, PGSSdrying and CAN-BD SCF, were also included in discussions. Among the limitations of the techniques involved, the poor solvent power of CO2, the cost and necessity of voluminous usage of the CO2 can be mentioned. There is still confusion in contribution of each variable on the particle morphology and properties regardless of the number of mechanistic studies available. The advantages of especially SAS and PGSS based techniques are the production of the nano or micro sized spherical particles with smooth surfaces and narrow particle size distribution. Regardless of its advantages, the reasons why 25 years of active research, and more than 10 years of process development could not promote the use of (SCF) technology, and produced only few commercial drug products, necessitate further evaluation of

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    Nediljko Budisa

    2014-08-01

    Full Text Available 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.

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

    Science.gov (United States)

    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.

  17. Industrial applications and current trends in supercritical fluid technologies

    OpenAIRE

    Gamse Thomas

    2005-01-01

    Supercritical fluids have a great potential for wide fields of processes Although CO2 is still one of the most used supercritical gases, for special purposes propane or even fluorinated-chlorinated fluids have also been tested. The specific characteristics of supercritical fluids behaviour were analyzed such as for example the solubilities of different components and the phase equilibria between the solute and solvent. The application at industrial scale (decaffeinating of tea and coffee, hop...

  18. Continuous Process for the Etching, Rinsing and Drying of MEMS Using Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Min, Seon Ki; Han, Gap Su; You, Seong-sik [Korea University of Technology and Education, Cheonan (Korea, Republic of)

    2015-10-15

    The previous etching, rinsing and drying processes of wafers for MEMS (microelectromechanical system) using SC-CO{sub 2} (supercritical-CO{sub 2}) consists of two steps. Firstly, MEMS-wafers are etched by organic solvent in a separate etching equipment from the high pressure dryer and then moved to the high pressure dryer to rinse and dry them using SC-CO{sub 2}. We found that the previous two step process could be applied to etch and dry wafers for MEMS but could not confirm the reproducibility through several experiments. We thought the cause of that was the stiction of structures occurring due to vaporization of the etching solvent during moving MEMS wafer to high pressure dryer after etching it outside. In order to improve the structure stiction problem, we designed a continuous process for etching, rinsing and drying MEMS-wafers using SC-CO{sub 2} without moving them. And we also wanted to know relations of states of carbon dioxide (gas, liquid, supercritical fluid) to the structure stiction problem. In the case of using gas carbon dioxide (3 MPa, 25 .deg. C) as an etching solvent, we could obtain well-treated MEMS-wafers without stiction and confirm the reproducibility of experimental results. The quantity of rinsing solvent used could be also reduced compared with the previous technology. In the case of using liquid carbon dioxide (3 MPa, 5 .deg. C), we could not obtain well-treated MEMS-wafers without stiction due to the phase separation of between liquid carbon dioxide and etching co-solvent(acetone). In the case of using SC-CO{sub 2} (7.5 Mpa, 40 .deg. C), we had as good results as those of the case using gas-CO{sub 2}. Besides the processing time was shortened compared with that of the case of using gas-CO{sub 2}.

  19. Inactivation of E. coli K12 in buffered peptone water and apple cider by pilot-plant scale supercritical carbon dioxide system

    Science.gov (United States)

    There is increasing interest in non-thermal processing to inactivate foodborne pathogens and background microflora in juice products. Non-thermal pasteurization ensures safety and may offer better quality products than thermal pasteurization. Of non-thermal technologies, use of supercritical carbon ...

  20. Solubility correlation of anthraquinone derivatives in supercritical carbon dioxide

    Science.gov (United States)

    Alwi, Ratna Surya; Tamura, Kazuhiro; Tanaka, Tatsuro; Shimizu, Keisuke

    2017-05-01

    In this work, solubilites of anthraquinone dyestuffs in supercritical carbon dioxide (sc-CO2) were correlated by semiempirical models, expressed in terms of CO2 density. All solubility data used, experimentally measured by us, and were described in details elsewhere; namely, 1,4-diaminoanthraquinone and 1,4-bis(ethylamino)anthraquinone [J. Chem. Thermo-dyn. 74, 119-125 (2014)]; 1-amino-4-hydroxyanthraquinone and 1-hydroxy-4-nitroanthraquionone [Dyes Pigm.113, 351-356 (2015)]; 1,4-diamino-2,3-dichloroanthraquinone and 1,8-dihydroxy-4,5-dinitroanthraquinone [J. Chem. Eng. Data 60, 3046-3052 (2015)], and 1-aminoanthraquinone and 1-nitroanthraquinone [J. Chem. Thermodyn. 104, 162-168 (2017)]. It was found that 1-aminoanthraquinone shows the highest solubility at 383,15 K and pressure of 25 MPa, and the solubility of anthraquinone derivatives in sc-CO2 changed by the substituent groups. Satisfactory agreement between the experimental data used and calculated solubilities of the anthraquinone derivatives was obtained.

  1. Computational Fluid Dynamics Analysis of Supercritical Carbon Dioxide Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae W.; Kim, Nam H.; Suh, Kune Y. [Seoul National University, Seoul (Korea, Republic of); Kim, Seung O. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2007-07-01

    The supercritical carbon dioxide (SCO{sub 2}) gas turbine Brayton cycle has been not only adopted in the secondary loop of the Generation IV nuclear energy systems but also planned to be installed in the high efficiency power conversion cycles of the nuclear fusion reactors. The potential beneficiaries include the Korea Advanced Liquid Metal Reactor (KALIMER), the Korea Superconducting Tokamak Advanced Research (KSTAR) as well as the International Thermonuclear Experimental Reactor (ITER). The reason for these welcomed applications is that the cycle can achieve the overall energy conversion efficiency as high as 45%. The SCO{sub 2} turbine efficiency is one of the major parameters affecting the overall Brayton cycle efficiency. Thus, optimal turbine design determines the economics of the Generation IV as well as the future nuclear fission and fusion energy industry. Seoul National University has recently been working on the SCO{sub 2} based Modular Optimized Brayton Integral System (MOBIS). MOBIS includes the Gas Advanced Turbine Operation Study (GATOS), the Loop Operating Brayton Optimization Study (LOBOS), the Nonsteady Operation Multidimensional Online Simulator (NOMOS), and the Turbine Advanced Compressor Operation Study (TACOS). This paper presents results from GATOS.

  2. Computational Fluid Dynamics Analysis of Supercritical Carbon Dioxide Turbine

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae W.; Kim, Nam H.; Suh, Kune Y. [Seoul National University, Seoul (Korea, Republic of); Kim, Seung O. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2006-07-01

    The supercritical carbon dioxide (SCO{sub 2}) gas turbine Brayton cycle has been not only adopted in the secondary loop of the Generation IV nuclear energy systems but also planned to be installed in the high efficiency power conversion cycles of the nuclear fusion reactors. The potential beneficiaries include the Korea Advanced Liquid Metal Reactor (KALIMER), Korea Superconducting Tokamak Advanced Research (KSTAR) and International Thermonuclear Experimental Reactor (ITER). The reason for these welcomed applications is that the cycle can achieve the overall energy conversion efficiency as high as 45%. The SCO{sub 2} turbine efficiency is one of the major parameters affecting the overall Brayton cycle efficiency. Thus, optimal turbine design determines the economics of the Generation IV as well as the future nuclear fission and fusion energy industry. Seoul National University has recently been working on the SCO{sub 2} based Modular Optimized Brayton Integral System (MOBIS). MOBIS includes the Gas Advanced Turbine Operation Study (GATOS), the Loop Operating Brayton Optimization Study (LOBOS), the Nonsteady Operation Multidimensional Online Simulator (NOMOS), and the Turbine Advanced Compressor Operation Study (TACOS). This paper presents first results from GATOS.

  3. Supercritical Carbon Dioxide-Assisted Decellularization of Aorta and Cornea.

    Science.gov (United States)

    Guler, Selcan; Aslan, Bahar; Hosseinian, Pezhman; Aydin, Halil Murat

    2017-09-01

    Tissue engineering approaches utilize both natural and synthetic materials in the repair and regeneration processes. A naturally sourced material for this purpose is required to be free from any antigenic matter such as cells or cellular components. Decellularization of tissues may be achieved through chemical or physical removal agents. Supercritical carbon dioxide (sc-CO2) has been used on the purpose of removing bioburden from tissues and offers an alternative to the traditionally used treatment methods. In addition to many advantages it offers with regard to the successful decellularization of tissues, it is known to have a sterilization effect. This study provides an insight into sc-CO2-assisted decellularization trials of corneal and aortic tissues. Results showed that high pressure of the fluid bursts the cells during the treatment and rapid depressurization was found to be effective in the removal of the cells from the tissues. sc-CO2 decellularization offers significantly reduced treatment times, complete decellularization, and preserved extracellular matrix structure.

  4. Low temperature synthesis of fibres composed of carbon-nickel nanoparticles in super-critical carbon dioxide

    Science.gov (United States)

    Hasumura, Takashi; Fukuda, Takahiro; Whitby, Raymond L. D.; Aschenbrenner, Ortrud; Maekawa, Toru

    2010-06-01

    We show that fibres composed of carbon-nickel nanoparticles are self-assembled by mixing nickelocene and oxygen with super-critical carbon dioxide in a dc electric field. The fibres grow in the direction of the electric field and the growth rate increases with an increase in the strength of the electric field. We also irradiate the fibres with electron beams and find that crystallized nickel particles are captured by carbon particles. The present result suggests that a low temperature method of creating carbon-metal hybrid nanostructures may be developed by mixing metallocene and trigger molecules with super-critical fluids subjected to a dc electric field.

  5. Enhancing Phenolic Contents and Antioxidant Potentials of Antidesma thwaitesianum by Supercritical Carbon Dioxide Extraction

    Directory of Open Access Journals (Sweden)

    Warut Poontawee

    2015-01-01

    Full Text Available Supercritical fluid extraction (SFE has increasingly gained attention as an alternative technique for extraction of natural products without leaving toxic residues in extracts. Antidesma thwaitesianum Muell. Arg. (Phyllanthaceae, or ma mao, has been reported to exhibit antioxidant health benefits due to its phenolic constituents. To determine whether SFE technique could impact on phenolic contents and associated antioxidant potentials, ripe fruits of Antidesma thwaitesianum (Phyllanthaceae were extracted using supercritical carbon dioxide (SC-CO2 and conventional solvents (ethanol, water. The results showed that the SC-CO2 extract contained significantly higher yield, total phenolic, flavonoid, and proanthocyanidin contents than those obtained from ethanol and water. It also demonstrated the greatest antioxidant activities as assessed by ABTS radical cation decolorization, DPPH radical scavenging, and ferric reducing antioxidant power (FRAP assays. Further analysis using high-performance liquid chromatography with diode array and mass spectrometry detectors (HPLC-DAD/MSD revealed the presence of catechin as a major phenolic compound of Antidesma thwaitesianum (Phyllanthaceae, with the maximum amount detected in the SC-CO2 extract. These data indicate that SFE technology improves both quantity and quality of Antidesma thwaitesianum fruit extract. The findings added more reliability of using this technique to produce high added value products from this medicinal plant.

  6. Lignin depolymerisation in supercritical carbon dioxide/acetone/water fluid for the production of aromatic chemicals.

    Science.gov (United States)

    Gosselink, Richard J A; Teunissen, Wouter; van Dam, Jan E G; de Jong, Ed; Gellerstedt, Göran; Scott, Elinor L; Sanders, Johan P M

    2012-02-01

    Valorisation of lignin plays a key role in further development of lignocellulosic biorefinery processes the production of biofuels and bio-based materials. In the present study, organosolv hardwood and wheat straw lignins were converted in a supercritical fluid consisting of carbon dioxide/acetone/water (300-370°C, 100bar) to a phenolic oil consisting of oligomeric fragments and monomeric aromatic compounds with a total yield of 10-12% based on lignin. These yields are similar to the state-of-the-art technologies such as base-catalysed thermal processes applied for lignin depolymerisation. Addition of formic acid increases the yield of monomeric aromatic species by stabilizing aromatic radicals. Supercritical depolymerisation of wheat straw and hardwood lignin yielded monomeric compounds in different compositions with a maximum yield of 2.0% for syringic acid and 3.6% for syringol, respectively. The results of the present study showed that under the applied conditions competition occurred between lignin depolymerisation and recondensation of fragments.

  7. Desorption of toluene from modified clays using supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    Carneiro D. G. P.

    2004-01-01

    Full Text Available The main objective of this work is to study the regeneration capacity of modified clays using supercritical fluid. These modified clays are used as organic compound adsorvents. The experimental step was done using a packed column with the clay contaminated by toluene. The results obtained showed the influence of the density of the supercritical CO2 and of the organic modifier in the desorption process. These data were modeled with first- and second-order models. Better results were obtained using the second-order model. This study makes possible the scale-up of the desorption process for regeneration of solid matrices using supercritical fluids.

  8. Evidence for Carbonate Surface Complexation during Forsterite Carbonation in Wet Supercritical Carbon Dioxide.

    Science.gov (United States)

    Loring, John S; Chen, Jeffrey; Bénézeth, Pascale; Qafoku, Odeta; Ilton, Eugene S; Washton, Nancy M; Thompson, Christopher J; Martin, Paul F; McGrail, B Peter; Rosso, Kevin M; Felmy, Andrew R; Schaef, Herbert T

    2015-07-14

    Continental flood basalts are attractive formations for geologic sequestration of carbon dioxide because of their reactive divalent-cation containing silicates, such as forsterite (Mg2SiO4), suitable for long-term trapping of CO2 mineralized as metal carbonates. The goal of this study was to investigate at a molecular level the carbonation products formed during the reaction of forsterite with supercritical CO2 (scCO2) as a function of the concentration of H2O adsorbed to the forsterite surface. Experiments were performed at 50 °C and 90 bar using an in situ IR titration capability, and postreaction samples were examined by ex situ techniques, including scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), focused ion beam transmission electron microscopy (FIB-TEM), thermal gravimetric analysis mass spectrometry (TGA-MS), and magic angle spinning nuclear magnetic resonance (MAS NMR). Carbonation products and reaction extents varied greatly with adsorbed H2O. We show for the first time evidence of Mg-carbonate surface complexation under wet scCO2 conditions. Carbonate is found to be coordinated to Mg at the forsterite surface in a predominately bidentate fashion at adsorbed H2O concentrations below 27 μmol/m(2). Above this concentration and up to 76 μmol/m(2), monodentate coordinated complexes become dominant. Beyond a threshold adsorbed H2O concentration of 76 μmol/m(2), crystalline carbonates continuously precipitate as magnesite, and the particles that form are hundreds of times larger than the estimated thicknesses of the adsorbed water films of about 7 to 15 Å. At an applied level, these results suggest that mineral carbonation in scCO2 dominated fluids near the wellbore and adjacent to caprocks will be insignificant and limited to surface complexation, unless adsorbed H2O concentrations are high enough to promote crystalline carbonate formation. At a fundamental level, the surface complexes and their dependence on adsorbed H2O

  9. Supercritical fluid (SCF) technologies: Assessment of applicability to installation restoration processes

    Science.gov (United States)

    1994-03-01

    USAEC has conducted an evaluation of supercritical fluid (SCF) technologies for their applicability to treatment of explosives, chlorinated hydrocarbons, and metals in soils, water, and/or waste sludge media. Off-specification explosives and propellants that have traditionally been open burned or openly detonated were also examined. Supercritical fluids are substances which have been heated and compressed to above their critical temperatures and pressures and which possess unique transport and mass transfer properties. Supercritical fluid extraction (SFE) uses the solvating properties of supercritical fluids to extract one or more organic components from a mixture into a supercritical solvent (commonly CO2). The concentrated extract stream may then be recycled, reclaimed, or destroyed by other methods.

  10. A New Process for Synthesis of Dimethyl Carbonate from Ethylene Carbonate and Methanol without any Catalyst under Supercritical Conditions

    Institute of Scientific and Technical Information of China (English)

    Xiu Juan FENG; Xiao Gang LI; Ren HE; Hui ZHOU

    2005-01-01

    Dimethyl carbonate was synthesized by transesterification reaction between ethylene carbonate and methanol under supercritical conditions without any catalyst. Experimental results showed that the residence time and the molar ratio of methanol to ethylene carbonate all can affect the conversion of ethylene carbonate. When the molar ratio of methanol to ethylene carbonate was 8:1, 81.2 % conversion can be achieved at 9.0 MPa and 250℃ after 8 h.

  11. Extraction/fractionation and deacidification of wheat germ oil using supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    P. Zacchi

    2006-03-01

    Full Text Available Wheat germ oil was obtained by mechanical pressing using a small-scale screw press and by supercritical extraction in a pilot plant. With this last method, different pressures and temperatures were tested and the tocopherol concentration in the extract was monitored during extraction. Then supercritical extracted oil as well as commercial pressed oil were deacidified in a countercurrent column using supercritical carbon dioxide as solvent under different operating conditions. Samples of extract, refined oil and feed oil were analyzed for free fatty acids (FFA and tocopherol contents. The results show that oil with a higher tocopherol content can be obtained by supercritical extraction-fractionation and that FFA can be effectively removed by countercurrent rectification while the tocopherol content is only slightly reduced.

  12. Measurement and theoretical analysis of the adsorption of supercritical methane on superactivated carbon

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Adsorption/desorption isotherms of supercritical methane on superactivated carbon have been measured in the range of 0 10 MPa and 233 333 K (20 K interval). The reversibility of the physical adsorption process is acknowledged. The heat of adsorption of 16.5 kJ/mol is determined from the isotherms, and a new modeling strategy for isotherms with maximum is presented. The model yields fits to the experimental isotherms with precision of ±2%, maintaining the constancy of the characteristic energy of adsorption. The exponent of the model equation expresses the pore size distribution feature of the adsorbent. The density of the supercritical adsorbate is evaluated as a parameter of the model. It is shown that the conventional isotherm theory works too at supercritical condition if the limit state of supercritical adsorption is introduced into isotherm modeling.

  13. Measurement and theoretical analysis of the adsorption of supercritical methane on superactivated carbon

    Institute of Scientific and Technical Information of China (English)

    周理; 李明; 周亚平

    2000-01-01

    Adsorption/desorption isotherms of supercritical methane on superactivated carbon have been measured in the range of 0-10 MPa and 233-333 K (20 K interval). The reversibility of the physical adsorption process is acknowledged. The heat of adsorption of 16.5 kJ/mol is determined from the isotherms, and a new modeling strategy for isotherms with maximum is presented. The model yields fits to the experimental isotherms with precision of ?%, maintaining the constancy of the characteristic energy of adsorption. The exponent of the model equation expresses the pore size distribution feature of the adsorbent. The density of the supercritical adsor-bate is evaluated as a parameter of the model. It is shown that the conventional isotherm theory works too at supercritical condition if the limit state of supercritical adsorption is introduced into isotherm modeling.

  14. 超临界条件下苯酚在活性炭和聚合物吸附剂上吸附等温线的测定%Estimation of the Isotherms of Phenol on Activated Carbons and Polymeric Adsorbents under Supercritical Condition

    Institute of Scientific and Technical Information of China (English)

    奚红霞; 谢兰英; 李祥斌; 李忠

    2003-01-01

    A method named as "volume-expanding and pressure-reducing adsorption" is proposed. It can be usedto measure the isotherms under supercritical condition. The adsorption isotherms of phenol on activated carbonsand polymeric adsorbents are estimated and compared respectively for the systems of "phenol-activated carbon-supercritical fluid CO2" and "phenol-polymeric adsorbent-supercritical fluid CO2". The results show that theamount of phenol adsorbed on the activated carbons and the polymeric adsorbents under the supercritical conditionis much less than that under the general condition, which can be utilized to develop a technology regenerating theactivated carbon with supercritical fluid. Moreover, the effects of ethyl alcohol, used as the third component, on theisotherms of phenol on the activated carbons and polymeric adsorbents under the supercritical condition are alsoinvestigated.

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

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    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 be-tween 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 fac-tor of mass-transfer coefficient is brought forward, which describes the mathe-matical 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 extrac-tion 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.

  16. Characteristics modeling for supercritical circulating fluidized bed boiler working in oxy-combustion technology

    Directory of Open Access Journals (Sweden)

    Balicki Adrian

    2014-06-01

    Full Text Available Among the technologies which allow to reduce greenhouse gas emission, mainly carbon dioxide, special attention deserves the idea of ‘zeroemission’ technology based on boilers working in oxy-combustion technology. In the paper the results of analyses of the influence of changing two quantities, namely oxygen share in oxidant produced in the air separation unit, and oxygen share in oxidant supplied to the furnace chamber on the selected characteristics of a steam boiler including the degree of exhaust gas recirculation, boiler efficiency and adiabatic flame temperature, was examined. Due to the possibility of the integration of boiler model with carbon dioxide capture, separation and storage installation, the subject of the analysis was also to determine composition of the flue gas at the outlet of a moisture condensation installation. Required calculations were made using a model of a supercritical circulating fluidized bed boiler working in oxy-combustion technology, which was built in a commercial software and in-house codes.

  17. Combined extraction processes of lipid from chlorella vulgaris microalgae: microwave prior to supercritical carbon dioxide extraction

    OpenAIRE

    Farid Chemat; Frederic Charton; Céline Dejoye; Maryline Abert Vian; Guy Lumia; Christian Bouscarle

    2011-01-01

    Extraction yields and fatty acid profiles from freeze-dried Chlorella vulgaris by microwave pretreatment followed by supercritical carbon dioxide (MW-SCCO2) extraction were compared with those obtained by supercritical carbon dioxide extraction alone (SCCO2). Work performed with pressure range of 20–28 Mpa and temperature interval of 40–70 °C, gave the highest extraction yield (w/w dry weight) at 28 MPa/40 °C. MW-SCCO2 allowed to obtain the highest extraction yield (4.73%) compared to SCCO2 e...

  18. Direct synthesis of dimethyl carbonate and propylene glycol using potassium bicarbonate as catalyst in supercritical CO2

    National Research Council Canada - National Science Library

    Yicun Wen; Rui Zhang; Yu Cang; Jianchao Zhang; Lixiao Liu; Xuhong Guo; Bin Fan

    2015-01-01

    The improved one-pot synthesis of dimethyl carbonate and propylene glycol from propylene oxide, supercritical carbon dioxide, and methanol with potassium bicarbonate as the catalyst has been reported in this paper...

  19. Selective Extraction of Uranium from Liquid or Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Farawila, Anne F.; O' Hara, Matthew J.; Wai, Chien M.; Taylor, Harry Z.; Liao, Yu-Jung

    2012-07-31

    Current liquid-liquid extraction processes used in recycling irradiated nuclear fuel rely on (1) strong nitric acid to dissolve uranium oxide fuel, and (2) the use of aliphatic hydrocarbons as a diluent in formulating the solvent used to extract uranium. The nitric acid dissolution process is not selective. It dissolves virtually the entire fuel meat which complicates the uranium extraction process. In addition, a solvent washing process is used to remove TBP degradation products, which adds complexity to the recycling plant and increases the overall plant footprint and cost. A liquid or supercritical carbon dioxide (l/sc -CO2) system was designed to mitigate these problems. Indeed, TBP nitric acid complexes are highly soluble in l/sc -CO2 and are capable of extracting uranium directly from UO2, UO3 and U3O8 powders. This eliminates the need for total acid dissolution of the irradiated fuel. Furthermore, since CO2 is easily recycled by evaporation at room temperature and pressure, it eliminates the complex solvent washing process. In this report, we demonstrate: (1) A reprocessing scheme starting with the selective extraction of uranium from solid uranium oxides into a TBP-HNO3 loaded Sc-CO2 phase, (2) Back extraction of uranium into an aqueous phase, and (3) Conversion of recovered purified uranium into uranium oxide. The purified uranium product from step 3 can be disposed of as low level waste, or mixed with enriched uranium for use in a reactor for another fuel cycle. After an introduction on the concept and properties of supercritical fluids, we first report the characterization of the different oxides used for this project. Our extraction system and our online monitoring capability using UV-Vis absorbance spectroscopy directly in sc-CO2 is then presented. Next, the uranium extraction efficiencies and kinetics is demonstrated for different oxides and under different physical and chemical conditions: l/sc -CO2 pressure and temperature, TBP/HNO3 complex used

  20. Degradation of lindane and hexachlorobenzene in supercritical carbon dioxide using palladium nanoparticles stabilized in microcellular high-density polyethylene.

    Science.gov (United States)

    Wu, Bei-Zen; Chen, GuanYu; Yak, HwaKwang; Liao, Weisheng; Chiu, KongHwa; Peng, Shie-Ming

    2016-06-01

    Palladium nanoparticles stabilized in microcellular high-density polyethylene prepared through supercritical foaming, supercritical impregnation, and H2 reduction are used for the hydrodechlorination of lindane and hexachlorobenzene in supercritical carbon dioxide below 100 °C. Both lindane and hexachlorobenzene can be almost 100% transformed to cyclohexane in 1 h. Reaction intermediates, such as lower chlorinated products or benzene, are not observed or exist in trace amount indicating that most of them may undergo reactions without leaving the metal surface.

  1. Recovery of gold from spent matrices using supercritical carbon dioxide / Pieter Gideon van Zyl

    OpenAIRE

    2007-01-01

    The feasibility of recovering gold preloaded onto activated carbon by supercritical carbon dioxide (sc-CO2) was investigated in view of the actuality of a more environmentally friendly process for the retrieval of gold from real-world matrices (ion-exchange resin, cellulose, activated carbon) than the harsh elution methods currently employed. Several complexes of gold(I) and gold(III) were synthesised and characterised (AA, uv/visible), and their solubility in sc-CO2 investi...

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

    Energy Technology Data Exchange (ETDEWEB)

    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 be 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 temperature

  3. Carbonation of Rock Minerals by Supercritical Carbon Dioxide at 250 degrees C.

    Energy Technology Data Exchange (ETDEWEB)

    Sugama, T.; Ecker, L.; Butcher, T.

    2010-06-01

    Wet powder-samples of five rock minerals, granite, albite, hornblende, diorite, and biotite mica, were exposed in supercritical carbon dioxide (scCO2) for 3 days at 250 C under 17.23 MPa pressure, and then the susceptibility of the various crystalline phases present in these mineral structures to reactions with hot scCO2 was investigated by XRD and FT-IR. The anorthite present in diorite was identified as the most vulnerable phase to carbonation. In contrast, biotite displayed a great resistance, although its phase was transformed hydrothermally to sanidine and quartz. Granite comprised of two phases, anorthoclase-type albite and quartz. The carbonation of former phase led to the formation of amorphous sodium and potassium carbonates coexisting with the clay-like by-products of the carbonation reaction. The reactivity of quartz to scCO2 was minimal, if any. Among these rock minerals, only hornblende formed crystalline carbonation products, such as calcite and magnesite after exposure, reflecting the likelihood of an increase in its volume. Based upon the feldspar ternary diagram, the carbonation rate of various different minerals in the plagioclase feldspar family depended primarily on the amount of anorthite. On the other hand, alkali feldspar minerals involving anorthoclase-type albite and sanidine had a lower reactivity with scCO2, compared with that of plagioclase feldspar minerals.

  4. Corrosion of Candidate High Temperature Alloys in Supercritical Carbon Dioxide

    Science.gov (United States)

    Parks, Curtis J.

    The corrosion resistance of three candidate alloys is tested in supercritical carbon dioxide (S-CO2) at different levels of temperature and pressure for up to 3000 hours. The purpose of the testing is to evaluate the compatibility of different engineering alloys in S-CO2 for use in a S-CO 2 Brayton cycle. The three alloys used are austenitic stainless steel 316, iron-nickel-base superalloy 718, and nickel-base superalloy 738. Each alloy is exposed to four combinations of temperature and pressure, consisting of either 550°C or 700°C at either 15 or 25 MPa for up to 1500 hours. At each temperature, an additional sample set is tested for 3000 hours and experienced an increase in pressure from 15 MPa to 25 MPa after 1500 hours of testing. All three alloys are successful in producing a protective oxide layer at the lower temperature of 550°C based on the logarithmic weight gain trends. At the higher temperature of 700°C, 316SS exhibits unfavourable linear weight gain trends at both pressures of 15 and 25 MPa. In comparison, IN-718 and IN-738 performs similarly in producing a protective oxide layer illustrated through a power weight gain relation. The effect of pressure is most pronounced at the operating temperature of 700°C, where the higher pressure of 25 MPa results in an increased rate of oxide formation. SEM analysis exposes a thin film oxide for both IN-718 and IN-738 but severe intergranular corrosion is exhibited by IN-738. Based on the testing conducted, both alloys show favourable characteristics for use in S-CO 2 conditions up to 700°C, but further testing is required to characterize the effect of the intergranular corrosion on the stability of oxide in IN-738. 316SS provided favourable results for use in temperatures of 550°C, but the protective oxide deteriorated at an operating temperature of 700°C.

  5. Supercritical carbon dioxide extracted extracellular matrix material from adipose tissue.

    Science.gov (United States)

    Wang, Jun Kit; Luo, Baiwen; Guneta, Vipra; Li, Liang; Foo, Selin Ee Min; Dai, Yun; Tan, Timothy Thatt Yang; Tan, Nguan Soon; Choong, Cleo; Wong, Marcus Thien Chong

    2017-06-01

    Adipose tissue is a rich source of extracellular matrix (ECM) material that can be isolated by delipidating and decellularizing the tissue. However, the current delipidation and decellularization methods either involve tedious and lengthy processes or require toxic chemicals, which may result in the elimination of vital proteins and growth factors found in the ECM. Hence, an alternative delipidation and decellularization method for adipose tissue was developed using supercritical carbon dioxide (SC-CO2) that eliminates the need of any harsh chemicals and also reduces the amount of processing time required. The resultant SC-CO2-treated ECM material showed an absence of nuclear content but the preservation of key proteins such as collagen Type I, collagen Type III, collagen Type IV, elastin, fibronectin and laminin. In addition, other biological factors such as glycosaminoglycans (GAGs) and growth factors such as basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) were also retained. Subsequently, the resulting SC-CO2-treated ECM material was used as a bioactive coating on tissue culture plastic (TCP). Four different cell types including adipose tissue-derived mesenchymal stem cells (ASCs), human umbilical vein endothelial cells (HUVECs), immortalized human keratinocyte (HaCaT) cells and human monocytic leukemia cells (THP-1) were used in this study to show that the SC-CO2-treated ECM coating can be potentially used for various biomedical applications. The SC-CO2-treated ECM material showed improved cell-material interactions for all cell types tested. In addition, in vitro scratch wound assay using HaCaT cells showed that the presence of SC-CO2-treated ECM material enhanced keratinocyte migration whilst the in vitro cellular studies using THP-1-derived macrophages showed that the SC-CO2-treated ECM material did not evoke pro-inflammatory responses from the THP-1-derived macrophages. Overall, this study shows the efficacy of SC-CO2

  6. 超临界二氧化碳在核反应堆系统中的应用%Applications of Supercritical Carbon Dioxide in Nuclear Reactor System

    Institute of Scientific and Technical Information of China (English)

    黄彦平; 王俊峰

    2012-01-01

    The applications of supercritical carbon dioxide Brayton cycle in nuclear reactor systems have attracted worldwide attention in recent years. In this paper, the advantages of employing supercritical carbon dioxide Brayton cycle in nuclear reactors were analyzed based on its fundamental conception. The investigations on supercritical carbon dioxide Brayton cycle were reviewed. The potential application area of supercritical carbon dioxide in Chinese advanced nuclear energy technology were analyzed and discussed, and some associated suggestions were proposed.%基于超临界二氧化碳布雷顿循环的基本原理,分析其应用于核反应堆系统的主要优势,介绍目前国际上超临界二氧化碳应用于核反应堆系统的相关研究进展,对超临界二氧化碳工质在我国未来先进核能技术研发中潜在的应用对象进行探讨,并提出相关建议.

  7. A novel method of preparing metallic Janus silica particles using supercritical carbon dioxide

    NARCIS (Netherlands)

    Yang, Qiuyan; de Vries, Marcel H; Picchioni, Francesco; Loos, Katja

    2013-01-01

    In this study, we demonstrate a novel fabrication method to prepare metallic Janus silica particles by embedding nanosized silica particles on a spherical polystyrene (PS) substrate in supercritical carbon dioxide (sc CO2), followed by labelling with gold nanoparticles on the exposed part of the

  8. 179 Extraction of Coal-tar Pitch by Supercritical Carbon Dioxide ...

    African Journals Online (AJOL)

    Meyer

    Extraction of Coal-tar Pitch by Supercritical Carbon Dioxide. .... methanol in vials that were cooled with a mixture of ice and sodium chloride to avoid the loss of .... The data produced by our experiments may be utilised in a kinetic study of the.

  9. A novel method of preparing metallic Janus silica particles using supercritical carbon dioxide

    NARCIS (Netherlands)

    Yang, Qiuyan; de Vries, Marcel H; Picchioni, Francesco; Loos, Katja

    2013-01-01

    In this study, we demonstrate a novel fabrication method to prepare metallic Janus silica particles by embedding nanosized silica particles on a spherical polystyrene (PS) substrate in supercritical carbon dioxide (sc CO2), followed by labelling with gold nanoparticles on the exposed part of the sil

  10. Fractionation of whey protein isolate with supercritical carbon dioxide – process modeling and cost estimation

    Science.gov (United States)

    An economical and environmentally friendly whey protein fractionation process was developed using supercritical carbon dioxide (sCO2) as an acid to produce enriched fractions of alpha-lactalbumin (alpha-La) and beta-lactoglobulin (beta-Lg) from a commercial whey protein isolate (WPI) containing 55% ...

  11. Efficacy of supercritical carbon dioxide for nonthermal inactivation of Escherichia coli K12 in apple cider

    Science.gov (United States)

    This study evaluated the efficacy of a supercritical carbon dioxide (SCCO2) system with a gas-liquid porous metal contactor for eliminating Escherichia coli K12 in apple cider. Pasteurized, preservative-free apple cider was inoculated with E. coli K12 and processed using the SCCO2 system at CO2 conc...

  12. SELECTIVE HYDROGENATION OF ANHYDRIDES TO LACTONES UNDER SUPERCRITICAL CARBON DIOXIDE MEDIUM

    Science.gov (United States)

    Selective Hydrogenation of Anhydrides to Lactones Under Supercritical Carbon Dioxide MediumEndalkachew Sahle-Demessie Unnikrishnan R PillaiU.S. EPA , 26 W. Martin Luther King Dr. Cincinnati, OH 45268 Phone: 513-569-7739Fax: 513-569-7677Abstract:Hydrogenat...

  13. Green application of flame retardant cotton fabric using supercritical carbon dioxide

    Science.gov (United States)

    Due to its environmentally benign character, supercritical carbon dioxide (scCO2) is considered in green chemistry as a substitute for organic solvents in chemical reactions. In this poster, an innovative approach for preparation of flame retardant woven and nonwoven fabrics were obtained by utiliz...

  14. Highly water-soluble multi-walled carbon nanotubes amine-functionalized by supercritical water oxidation.

    Science.gov (United States)

    Chun, Kyoung-Yong; Moon, In-Kyu; Han, Joo-Hee; Do, Seung-Hoe; Lee, Jin-Seo; Jeon, Seong-Yun

    2013-11-07

    Multi-walled carbon nanotubes (MWNTs) have been amine-functionalized by eco-friendly supercritical water oxidation. The facilely functionalized MWNTs have high solubility (~84 mg L(-1)) in water and 78% transmittance at 30-fold dilution. The Tyndall effect is also shown for several liquids.

  15. Lignin depolymerisation in supercritical carbon dioxide/acetone/water fluid for the production of aromatic chemicals

    NARCIS (Netherlands)

    Gosselink, R.J.A.; Teunissen, W.; Dam, van J.E.G.; Jong, de E.; Gellerstedt, G.; Scott, E.L.; Sanders, J.P.M.

    2012-01-01

    Valorisation of lignin plays a key role in further development of lignocellulosic biorefinery processes the production of biofuels and bio-based materials. In the present study, organosolv hardwood and wheat straw lignins were converted in a supercritical fluid consisting of carbon dioxide/acetone/w

  16. Palladium-catalyzed homo-coupling of boronic acids with supported reagents in supercritical carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    Lei Zhou; Qiu Xiang Xu; Huan Feng Jiang

    2007-01-01

    Palladium-catalyzed homo-coupling of arylboronic acids could proceed smoothly with a commercially available resin functionlised by phosphino or amino group as the ligand in supercritical carbon dioxide thereby offering a simple and efficient protocol for the synthesis of symmetrical bi-aryl molecules and their higher homologues.

  17. Determination of Partial Molar Volumes of EPA and DHA Ethyl Esters in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The use of supercritical-fluid chromatography for determining partial molar volumes of ethyl esters of cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and cis -4,7,10,13,16,19- docosa-hexaenoic acid (DHA) in supercritical carbon dioxide is presented and discussed. Partial molar volumes of EPA and DHA esters are obtained from the variation of the retention properties with the density of mobile phase at 313.15 K, 323.15 K, 333.15 K and in the pressure range from 9 MPa to 21 MPa.

  18. Supercritical CO 2 -philic nanoparticles suitable for determining the viability of carbon sequestration in shale

    KAUST Repository

    Xu, Yisheng

    2015-01-01

    © The Royal Society of Chemistry. A fracture spacing less than a decimeter is probably required for the successful sequestration of CO2 in shale. Tracer experiments using inert nanoparticles could determine if a fracturing this intense has been achieved. Here we describe the synthesis of supercritical CO2-philic nanoparticles suitable for this application. The nanoparticles are ~50 nm in diameter and consist of iron oxide (Fe3O4) and silica (SiO2) cores functionalized with a fluorescent polymeric corona. The nanoparticles stably disperse in supercritical carbon dioxide (scCO2) and are detectable to concentrations of 10 ppm. This journal is

  19. Isomeric enhancement of davanone from natural davana oil aided by supercritical carbon dioxide.

    Science.gov (United States)

    Coleman, William Monroe; Dube, Michael Frances; Ashraf-Khorassani, Mehdi; Taylor, Larry Thomas

    2007-04-18

    The chemical nature of davanone isolated from natural davana oil via packed column preparative supercritical fluid chromatography with a carbon dioxide-based mobile phase has been defined. Analyses used to characterize davanone included nuclear magnetic resonance spectroscopy, optical rotation, mass spectrometry, headspace solid-phase microextraction, enantiomeric purity via gas chromatography (GC), and GC-coupled olfactometry. For comparison, natural davana oil was subjected to the same types of measurements. The enriched davanone sample was nearly 100% optically pure. This indicates that fractionation of the davana oil with supercritical fluids at near room temperature had little effect on the optical integrity of the sample.

  20. Deptermination of Partial Molar Volumes of EPA and DHA Ethyl Esters in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    MeiHUANG; XianDaWANG; 等

    2002-01-01

    The use of supercritical-fluid shromatogrphy for determining partial molar volumes of ethyl esters of cis-5,8,11,14,17-eicosapentaenoic acid (EPA) and cis-4,7,10,13,16,19-docosa-hexaenoic acid(DHA) in supercritical carbon dioxide is presented and discussed. Partial molar volumes of EPA and DHA esters are obtained from the variation of the retention properties with the density of mobile phase at 313.15K,323.15K,333.15K and in the pressure range from 9 MPa to 21 MPa.

  1. Water as a Direct Hydrogen Donor in Supercritical Carbon Di-oxide: A Novel and Efficient Zn-H2O-CO2 System for Chemo selective Reduction of Nitrobenzenes to Anilines

    Institute of Scientific and Technical Information of China (English)

    JIANG Huan-Feng; DONG Yao-Sen

    2008-01-01

    An eco-friendly and cheap Zn-H2O-CO2 system was presented for chemoselective reduction of nitrobenzenes to anilines with high yields (80%-97% isolated yields) in supercritical carbon dioxide. This process brings together the very important green chemistry technologies--the use of carbon dioxide as a solvent and the use of water as a hydrogen donor.

  2. NMR study comparing capillary trapping in Berea sandstone of air, carbon dioxide, and supercritical carbon dioxide after imbibition of water

    Science.gov (United States)

    Prather, Cody A.; Bray, Joshua M.; Seymour, Joseph D.; Codd, Sarah L.

    2016-02-01

    Nuclear magnetic resonance (NMR) techniques were used to study the capillary trapping mechanisms relevant to carbon sequestration. Capillary trapping is an important mechanism in the initial trapping of supercritical CO2 in the pore structures of deep underground rock formations during the sequestration process. Capillary trapping is considered the most promising trapping option for carbon sequestration. NMR techniques noninvasively monitor the drainage and imbibition of air, CO2, and supercritical CO2 with DI H2O at low capillary numbers in a Berea sandstone rock core under conditions representative of a deep underground saline aquifer. Supercritical CO2 was found to have a lower residual nonwetting (NW) phase saturation than that of air and CO2. Supercritical CO2 behaves differently than gas phase air or CO2 and leads to a reduction in capillary trapping. NMR relaxometry data suggest that the NW phase, i.e., air, CO2, or supercritical CO2, is preferentially trapped in larger pores. This is consistent with snap-off conditions being more favorable in macroscale pores, as NW fluids minimize their contact area with the solid and hence prefer larger pores.

  3. Extraction of copper ions by supercritical carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Complexation combined with supercritical fluid extraction was used to extract Cu2+ in this study. The effects of pressure, temperature, volume of CO2 on the efficiency of extraction were systematically investigated. At the optimum condition a 57.32% recovery was achieved. Addition of suitable amount of methanol(v/v = 5 % ) to the supercritical CO2 can increase in the extraction of Cu2+ (72.69 %, RSD = 2.12 %, n = 3). And the recovery can further increase in the presence of non-ionic surfactant Triton X-100 because of its function of solubilization. Surfactant was first used in the extraction of metal ions in the present study, and the results are satisfied (90.52%, RSD=2.20%, n =3).

  4. Design of Supercritical Carbon Dioxide Compressor Testing Loop

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Seong Gu; Lee, Jeong Ik; Ahn, Yoon Han; Lee, Je Kyoung [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Yoon, Ho Joon; Addad, Yacine [KUSTAR, Abu Dhabi (United Arab Emirates)

    2012-05-15

    For small and medium-sized reactors and Generation IV reactors such as sodium-cooled fast reactor are recently under development actively. The supercritical CO{sub 2} Brayton cycle is considered as an attractive cycle for the above mentioned nuclear systems. This is because the supercritical CO{sub 2} Brayton cycle (S-CO{sub 2} cycle) is especially effective to reduce the volume of power generation system, which occupies 1.5{approx}2 times more space than the primary nuclear system in general. Comparing to traditional water-vapor cycle and helium cycle, the S-CO{sub 2} system has relatively much less volume and component size. Therefore, S-CO{sub 2} cycle can be used for many purposes such as nuclear ship propulsion where volume requirement is strict, or a small nuclear reactor when it is constructed on geographically limited area

  5. Critical review of supercritical carbon dioxide extraction of selected oil seeds

    Directory of Open Access Journals (Sweden)

    Sovilj Milan N.

    2010-01-01

    Full Text Available Supercritical carbon dioxide extraction, as a relatively new separation technique, can be used as a very efficient process in the production of essential oils and oleoresins from many of plant materials. The extracts from these materials are a good basis for the new pharmaceutical products and ingredients in the functional foods. This paper deals with supercritical carbon dioxide extraction of selected oil seeds which are of little interest in classical extraction in the food industry. In this article the process parameters in the supercritical carbon dioxide extraction, such as pressure, temperature, solvent flow rate, diameter of gound materials, and moisture of oil seed were presented for the following seeds: almond fruits, borage seed, corn germ, grape seed, evening primrose, hazelnut, linseed, pumpkin seed, walnut, and wheat germ. The values of investigated parameters in supercritical extraction were: pressure from 100 to 600 bar, temperature from 10 to 70oC, diameter of grinding material from 0.16 to 2.0 mm, solvent flow used from 0.06 to 30.0 kg/h, amount of oil in the feed from 10.0 to 74.0%, and moisture of oil seed from 1.1 to 7.5%. The yield and quality of the extracts of all the oil seeds as well as the possibility of their application in the pharmaceutical and food, industries were analyzed.

  6. Eco-Friendly Disperse Dyeing and Functional Finishing of Nylon 6 Using Supercritical Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Tarek Abou Elmaaty

    2015-08-01

    Full Text Available In this work, a supercritical carbon dioxide assembly was successfully constructed for dyeing Nylon6 fabric. Primary experiments were carried out to confirm the possibility of bringing the dyeing up to factory scale. A series of disperse azo dyes with potential antibacterial activity were applied to dye the fabric under our study in supercritical carbon dioxide (scCO2. The factors affecting the dyeing conditions (i.e., dye concentration, time, temperature and pressure and functional properties were discussed and compared with those in aqueous dyeing. The comparison revealed that elimination of auxiliary chemicals such as salt, carrier or dispersing agent has no diverse effect on dyeing. The color strength of the dyed fabric evaluated by using K/S measurements increased by increasing dye concentration from 2% to 6% owf. (on weight of fabric. The nylon6 fabrics dyed in supercritical carbon dioxide have good fastness properties, and especially light fastness compared with conventional exhaustion dyeing. Antibacterial activity of the dyed samples under supercritical conditions was evaluated and the results showed excellent antibacterial efficiency.

  7. Catalytic nanoreactors in continuous flow: hydrogenation inside single-walled carbon nanotubes using supercritical CO2.

    Science.gov (United States)

    Chamberlain, Thomas W; Earley, James H; Anderson, Daniel P; Khlobystov, Andrei N; Bourne, Richard A

    2014-05-25

    One nanometre wide carbon nanoreactors are utilised as the reaction vessel for catalytic chemical reactions on a preparative scale. Sub-nanometre ruthenium catalytic particles which are encapsulated solely within single-walled carbon nanotubes offering a unique reaction environment are shown to be active when embedded in a supercritical CO2 continuous flow reactor. A range of hydrogenation reactions were tested and the catalyst displayed excellent stability over extended reaction times.

  8. Palladium-Catalyzed Oxidation of Dihydromyrcene to Citronellal in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    RAN, Xue-Guang(冉学光); JIANG, Huan-Feng(江焕峰); ZHU, Xin-Hai(朱新海)

    2004-01-01

    Citronellal was the major product of catalytic oxidation of dihydromyrcene with oxygen using the catalyst comprised of (MeCN)2PdClNO2 and CuCl2 in a tertiary alcohol in supercritical carbon dioxide. It was found that the chemoselectivity of the reaction and the yield of citronellal were greatly affected by the pressure of carbon dioxide, the reaction temperature and the molar ratio of Pd/Cu.

  9. Measurements of mixtures with carbon dioxide under supercritical conditions using commercial high pressure equipment

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Luciana L.P.R. de; Rutledge, Luis Augusto Medeiros; Moreno, Eesteban L.; Hovell, Ian; Rajagopal, Krishnaswamy [Universidade Federal do Rio de Janeiro (LATCA-EQ-UFRJ), RJ (Brazil). Escola de Quimica. Lab. de Termodinamica e Cinetica Aplicada

    2012-07-01

    There is a growing interest in studying physical properties of binary and multicomponent fluid mixtures with supercritical carbon dioxide (CO{sub 2}) over an extended range of temperature and pressure. The estimation of properties such as density, viscosity, saturation pressure, compressibility, solubility and surface tension of mixtures is important in design, operation and control as well as optimization of chemical processes especially in extractions, separations, catalytic and enzymatic reactions. The phase behaviour of binary and multicomponent mixtures with supercritical CO{sub 2} is also important in the production and refining of petroleum where mixtures of paraffin, naphthene and aromatics with supercritical fluids are often encountered. Petroleum fluids can present a complex phase behaviour in the presence of CO{sub 2}, where two-phase (VLE and LLE) and three phase regions (VLLE) might occur within ranges of supercritical conditions of temperature and pressure. The objective of this study is to develop an experimental methodology for measuring the phase behaviour of mixtures containing CO{sub 2} in supercritical regions, using commercial high-pressure equipment. (author)

  10. Study on elution ability of salicylic acid on ion exchange resins in supercritical carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    Ping YUAN; Jianguo CAI; Junjie GONG; Xiu DENG

    2009-01-01

    The elution ability of salicylic acid on ion exchange resins in supercritical carbon dioxide has been studied. Some factors influencing elution recovery,including entrainer, temperature, pressure and the flow rate of supercritical fluid CO2 are discussed in this work.The addition of a small amount of entrainer, such as ethanol, triethanolamine and their mixture to supercritical CO2 can cause dramatic effects on the elution ability. The results show that the salicylic acid can be only slightly eluted from the resin with supercritical CO2 alone with temperatures ranging from 307.15 to 323.15K and pressures ranging from 10 to 30MPa. Meanwhile, with the same T, P conditions, 40.58% and 73.08% salicylic acid can be eluted from the ion exchange resin with ethanol and ethanol + triethanolamine as the entrainer, respec-tively. An improved PR equation of state with VDWl mixing rules is used to calculate the elution recovery of salicylic acid in supercritical CO2 and the results agree well with the experimental data.

  11. Multiphase fluid-rock reactions among supercritical carbon dioxide, brine, aquifer, and caprock: relevance to geologic sequestration of carbon

    Energy Technology Data Exchange (ETDEWEB)

    Kaszuba, J. P. (John P.); Janecky, D. R. (David R.); Snow, M. G. (Marjorie G.)

    2004-01-01

    The reactive behavior of a multiphase fluid (supercritical CO{sub 2} and brine) under physical-chemical conditions relevant to geologic storage and sequestration in a carbon repository is largely unknown. Experiments were conducted in a flexible cell hydrothermal apparatus to evaluate multiphase fluid-rock (aquifer plus caprock) reactions that may impact repository integrity.

  12. WaiGao Qiao: taking supercritical technology to new heights

    Energy Technology Data Exchange (ETDEWEB)

    Kessel, W.; Weiss, G.; Kawa, P. [Alstom, Stuttgart (Germany)

    2006-06-15

    In their first two years of commercial life the two supercritical boilers of Wai Gao Qiao Phase II, at 900 MWe each the largest operating coal fired units in China and the largest tangentially fired bituminous coal fired boilers in the world have performed reliably and efficiently. 11 figs., 1 tab.

  13. Supercritical Water Gasification of Biomass: A Literature and Technology Overview

    NARCIS (Netherlands)

    Yakaboylu, O.; Harinck, J.; Smit, K.G.; De Jong, W.

    2014-01-01

    The supercritical water gasification process is an alternative to both conventional gasification as well as anaerobic digestion as it does not require drying and the process takes place at much shorter residence times; a few minutes at most. The drastic changes in the thermo-physical properties of w

  14. Microbial potential for carbon and nutrient cycling in a geogenic supercritical carbon dioxide reservoir.

    Science.gov (United States)

    Freedman, Adam J E; Tan, BoonFei; Thompson, Janelle R

    2017-06-01

    Microorganisms catalyze carbon cycling and biogeochemical reactions in the deep subsurface and thus may be expected to influence the fate of injected supercritical (sc) CO2 following geological carbon sequestration (GCS). We hypothesized that natural subsurface scCO2 reservoirs, which serve as analogs for the long-term fate of sequestered scCO2 , harbor a 'deep carbonated biosphere' with carbon cycling potential. We sampled subsurface fluids from scCO2 -water separators at a natural scCO2 reservoir at McElmo Dome, Colorado for analysis of 16S rRNA gene diversity and metagenome content. Sequence annotations indicated dominance of Sulfurospirillum, Rhizobium, Desulfovibrio and four members of the Clostridiales family. Genomes extracted from metagenomes using homology and compositional approaches revealed diverse mechanisms for growth and nutrient cycling, including pathways for CO2 and N2 fixation, anaerobic respiration, sulfur oxidation, fermentation and potential for metabolic syntrophy. Differences in biogeochemical potential between two production well communities were consistent with differences in fluid chemical profiles, suggesting a potential link between microbial activity and geochemistry. The existence of a microbial ecosystem associated with the McElmo Dome scCO2 reservoir indicates that potential impacts of the deep biosphere on CO2 fate and transport should be taken into consideration as a component of GCS planning and modelling. © 2017 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

  15. Preparation of Chitosan-Based Hemostatic Sponges by Supercritical Fluid Technology

    Directory of Open Access Journals (Sweden)

    Hu-Fan Song

    2014-03-01

    Full Text Available Using ammonium bicarbonate (AB particles as a porogen, chitosan (CS-based hemostatic porous sponges were prepared in supercritical carbon dioxide due to its low viscosity, small surface tension, and good compatibility with organic solvent. Fourier transform infrared spectroscopy (FTIR spectra demonstrated that the chemical compositions of CS and poly-(methyl vinyl ether-co-maleic anhydride (PVM/MA were not altered during the phase inversion process. The morphology and structure of the sponge after the supercritical fluid (SCF process were observed by scanning electron microscopy (SEM. The resulting hemostatic sponges showed a relatively high porosity (about 80% with a controllable pore size ranging from 0.1 to 200 µm. The concentration of PVM/MA had no significant influence on the porosity of the sponges. Comparative experiments on biological assessment and hemostatic effect between the resulting sponges and Avitene® were also carried out. With the incorporation of PVM/MA into the CS-based sponges, the water absorption rate of the sponges increased significantly, and the CS-PVM/MA sponges showed a similar water absorption rate (about 90% to that of Avitene®. The results of the whole blood clotting experiment and animal experiment also demonstrated that the clotting ability of the CS-PVM/MA sponges was similar to that of Avitene®. All these results elementarily verified that the sponges prepared in this study were suitable for hemostasis and demonstrated the feasibility of using SCF-assisted phase inversion technology to produce hemostatic porous sponges.

  16. Valorization of olive pomace through combination of biocatalysis with supercritical fluid technology

    OpenAIRE

    Nogueira, João Humberto Gonçalves Francisco

    2015-01-01

    A supercritical carbon dioxide (scCO2) based oil extraction method was implemented on olive pomace (alperujo), and an oil yield of 25,5 +/- 0,8% (goil/gdry residue) was obtained. By Soxhlet extraction with hexane, an oil extraction yield of 28,9 +/- 0,8 % was obtained, which corresponds to an efficiency of 88,4 +/- 4,8 % for the supercritical method. The scCO2 extraction process was optimized for operating conditions of 50 MPa and 348,15 K, for which an oil loading of 32,60 g oil/kg CO2 was c...

  17. Supercritical CO2 Extraction of Rice Bran Oil -the Technology, Manufacture, and Applications.

    Science.gov (United States)

    Sookwong, Phumon; Mahatheeranont, Sugunya

    2017-06-01

    Rice bran is a good source of nutrients that have large amounts of phytochemicals and antioxidants. Conventional rice bran oil production requires many processes that may deteriorate and degrade these valuable substances. Supercritical CO2 extraction is a green alternative method for producing rice bran oil. This work reviews production of rice bran oil by supercritical carbon dioxide (SC-CO2) extraction. In addition, the usefulness and advantages of SC-CO2 extracted rice bran oil for edible oil and health purpose is also described.

  18. Methods for synthesizing diethyl carbonate from ethanol and supercritical carbon dioxide by one-pot or two-step reactions in the presence of potassium carbonate

    OpenAIRE

    Gasc, Fabien; Thiebaud-Roux, Sophie; Mouloungui, Zephirin

    2009-01-01

    Carbon dioxide sequestration was studied by synthesizing diethyl carbonate (DEC) from ethanol and CO2 under supercritical conditions in the presence of potassium carbonate as a base. The co-reagent was ethyl iodide or a concentrated strong acid. This sequestration reaction occurs in two steps, which were studied separately and in a one-pot reaction. An organic-inorganic carbonate hybrid, potassium ethyl carbonate (PEC) is generated at the end of the first step. This intermediate was character...

  19. Amino Acid Synthesis in a Supercritical Carbon Dioxide - Water System

    OpenAIRE

    2009-01-01

    Mars is a CO2-abundant planet, whereas early Earth is thought to be also CO2-abundant. In addition, water was also discovered on Mars in 2008. From the facts and theory, we assumed that soda fountains were present on both planets, and this affected amino acid synthesis. Here, using a supercritical CO2/liquid H2O (10:1) system which mimicked crust soda fountains, we demonstrate production of amino acids from hydroxylamine (nitrogen source) and keto acids (oxylic acid sources). In this research...

  20. Fiscal 1996 investigational research on the chemical process technology using supercritical fluids; 1996 nendo chorinkai ryutai wo riyoshita kagaku process gijutsu ni kansuru chosa kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    Importance was studied of making a research on the chemical process technology using the supercritical fluid. As for its effect on global warming, the amount of CO2 emission was compared during the operation between the conventional process and the process using the supercritical fluid, the CO2 reduction rate and amount were trially calculated, and a CO2 reduction of a several ten thousand ton scale in carbon conversion was predicted. As to hazardous materials and the reaction of waste retrieval, it was made clear that the process using the supercritical fluid was valid also for objects for which the chemical process used to be impossible, which indicates a possibility of the widening field of application. Concerning its effect on the energy conservation, energy reduction of several ten thousand tons in heavy oil conversion was predicted by replacing all the existing processes with supercritical fluids. Relating to the recycling, with the use of supercritical fluids, the process is possible which produces higher quality and yield and fewer unnecessary products such as char than the conventional process. 197 refs., 102 figs., 71 tabs.

  1. Green biodiesel production: a review on feedstock, catalyst, monolithic reactor, and supercritical fluid technology

    Directory of Open Access Journals (Sweden)

    Rizo Edwin Gumba

    2016-09-01

    Full Text Available The advancement of alternative energy is primarily catalyzed by the negative environmental impacts and energy depletion caused by the excessive usage of fossil fuels. Biodiesel has emerged as a promising substitute to petrodiesel because it is biodegradable, less toxic, and reduces greenhouse gas emission. Apart from that, biodiesel can be used as blending component or direct replacements for diesel fuel in automotive engines. A diverse range of methods have been reported for the conversion of renewable feedstocks (vegetable oil or animal fat into biodiesel with transesterification being the most preferred method. Nevertheless, the cost of producing biodiesel is higher compared to fossil fuel, thus impeding its commercialization potentials. The limited source of reliable feedstock and the underdeveloped biodiesel production route have prevented the full-scale commercialization of biodiesel in many parts of the world. In a recent development, a new technology that incorporates monoliths as support matrices for enzyme immobilization in supercritical carbon dioxide (SC-CO2 for continuous biodiesel production has been proposed to solve the problem. The potential of SC-CO2 system to be applied in enzymatic reactors is not well documented and hence the purpose of this review is to highlight the previous studies conducted as well as the future direction of this technology.

  2. Mathematical modeling and simulation of gel drying with supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    ALEKSANDAR ORLOVIC

    2005-02-01

    Full Text Available Mathematical models of alumina/silica gel supercritical drying with carbon dioxide were studied using supercritical drying experimental data. An alumina/silica gel with zinc chloride was synthesized and dried with superciritical carbon dioxide, and its weight change wasmonitored as a function of drying time. The pore size distribution of the obtained aerogel was determined using the BET method and nitrogen adsorption/desorption. Themathematical model of the supercritical drying of the wet gel was represented as unsteady and one-dimensional diffusion of solvent through the aerogel pores filled with supercitical carbon dioxide. Parallel pore model and pores in series model were developed on the basis of the measured porous structure of the aerogel. It was found that these models which use different effective diffusivity value for each pore size were in much better agreement with the experimental data than models which use an overall effective diffusivity. The local effective diffusivity coefficients were calculated using different tortuosity values for each pore size, and they were distributed according to the pore size distribution data. Model simulations of the superciritical drying with carbon dioxide confirmed that the drying temperature and gel particle diameter have a significant influence on the drying time.

  3. Implementing supercritical water oxidation technology in a lunar base environmental control/life support system

    Science.gov (United States)

    Meyer Sedej, M.

    1985-01-01

    A supercritical water oxidation system (SCWOS) offers several advantages for a lunar base environmental control/life support system (ECLSS) compared to an ECLSS based on Space Station technology. In supercritically heated water (630 K, 250 atm) organic materials mix freely with oxygen and undergo complete combustion. Inorganic salts lose solubility and precipitate out. Implementation of SCWOS can make an ECLSS more efficient and reliable by elimination of several subsystems and by reduction in potential losses of life support consumables. More complete closure of the total system reduces resupply requirements from the earth, a crucial cost item in maintaining a lunar base.

  4. Design and Test of Drilling and Completion Experimental System with Supercritical Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Du Yu-Kun

    2013-06-01

    Full Text Available Supercritical Carbon dioxide (SC-CO2 has many excellent properties, such as high rock-breaking efficiency, strong dissolved performance and good displacement efficiency. It is a high-efficiency fluid to exploit coal-bed methane, shale gas, heavy oil, low permeability reservoirs and other unconventional oil and gas reservoirs. Using SC-CO2 jet to break formation rock assisted the drill bit can get several times the penetration rate of conventional drilling and effectively enhance the oil recovery while achieving an initiative reduction of greenhouse gas by storing the CO2 underground in the proper unconventional reservoirs. The functions and process of drilling and completion experimental system are designed based on the SC-CO2 fluid properties and the actual operation conditions. Tests find that the remote control of the system is reliable, pressurization process is steady, sealing and operating performances are excellent. The system can effectively simulate the actual drilling and completion process with SC-CO2. The rock-breaking performance of SC-CO2 is much better than high pressure water jet which verifies the application superiority of SC-CO2 in rock-breaking drilling. The research lays basis for the development of SC-CO2 drilling and completion technology.

  5. Supercritical carbon dioxide extraction of carotenoids from pumpkin (Cucurbita spp.): a review.

    Science.gov (United States)

    Durante, Miriana; Lenucci, Marcello Salvatore; Mita, Giovanni

    2014-04-21

    Carotenoids are well known for their nutritional properties and health promoting effects representing attractive ingredients to develop innovative functional foods, nutraceutical and pharmaceutical preparations. Pumpkin (Cucurbita spp.) flesh has an intense yellow/orange color owing to the high level of carotenoids, mainly α-carotene, β-carotene, β-cryptoxanthin, lutein and zeaxanthin. There is considerable interest in extracting carotenoids and other bioactives from pumpkin flesh. Extraction procedures able to preserve nutritional and pharmacological properties of carotenoids are essential. Conventional extraction methods, such as organic solvent extraction (CSE), have been used to extract carotenoids from plant material for a long time. In recent years, supercritical carbon dioxide (SC-CO2) extraction has received a great deal of attention because it is a green technology suitable for the extraction of lipophylic molecules and is able to give extracts of high quality and totally free from potentially toxic chemical solvents. Here, we review the results obtained so far on SC-CO2 extraction efficiency and quali-quantitative composition of carotenoids from pumpkin flesh. In particular, we consider the effects of (1) dehydration pre-treatments; (2) extraction parameters (temperature and pressure); the use of water, ethanol and olive oil singularly or in combination as entrainers or pumpkin seeds as co-matrix.

  6. DISSOLUTION OF METAL OXIDES AND SEPARATION OF URANIUM FROM LANTHANIDES AND ACTINIDES IN SUPERCRITICAL CARBON DIOXIDE

    Energy Technology Data Exchange (ETDEWEB)

    Donna L. Quach; Bruce J. Mincher; Chien M. Wai

    2013-10-01

    This paper investigates the feasibility of extracting and separating uranium from lanthanides and other actinides by using supercritical fluid carbon dioxide (sc-CO2) as a solvent modified with tri-n-butylphosphate (TBP) for the development of a counter current stripping technique, which would be a more efficient and environmentally benign technology for spent nuclear fuel reprocessing compared to traditional solvent extraction. Several actinides (U, Pu, and Np) and europium were extracted in sc-CO2 modified with TBP over a range of nitric acid concentrations and then the actinides were exposed to reducing and complexing agents to suppress their extractability. According to this study, uranium/europium and uranium/plutonium extraction and separation in sc-CO2 modified with TBP is successful at nitric acid concentrations of less than 6 M and at nitric acid concentrations of less than 3 M with acetohydroxamic acid or oxalic acid, respectively. A scheme for recycling uranium from spent nuclear fuel by using sc-CO2 and counter current stripping columns is presented.

  7. Supercritical Carbon Dioxide Extraction of Carotenoids from Pumpkin (Cucurbita spp.: A Review

    Directory of Open Access Journals (Sweden)

    Miriana Durante

    2014-04-01

    Full Text Available Carotenoids are well known for their nutritional properties and health promoting effects representing attractive ingredients to develop innovative functional foods, nutraceutical and pharmaceutical preparations. Pumpkin (Cucurbita spp. flesh has an intense yellow/orange color owing to the high level of carotenoids, mainly α-carotene, β-carotene, β-cryptoxanthin, lutein and zeaxanthin. There is considerable interest in extracting carotenoids and other bioactives from pumpkin flesh. Extraction procedures able to preserve nutritional and pharmacological properties of carotenoids are essential. Conventional extraction methods, such as organic solvent extraction (CSE, have been used to extract carotenoids from plant material for a long time. In recent years, supercritical carbon dioxide (SC-CO2 extraction has received a great deal of attention because it is a green technology suitable for the extraction of lipophylic molecules and is able to give extracts of high quality and totally free from potentially toxic chemical solvents. Here, we review the results obtained so far on SC-CO2 extraction efficiency and quali-quantitative composition of carotenoids from pumpkin flesh. In particular, we consider the effects of (1 dehydration pre-treatments; (2 extraction parameters (temperature and pressure; the use of water, ethanol and olive oil singularly or in combination as entrainers or pumpkin seeds as co-matrix.

  8. Formation of reverse micelles in supercritical carbon dioxide and its thermodynamics

    Institute of Scientific and Technical Information of China (English)

    WEN Zhen; DANG Zhi; ZONG Minhua; ZHU Zhixin

    2007-01-01

    The solubilization behavior of methyl orange as a solvation probe in multiple systems composed of supercritical carbon dioxide,surfactants and co-solvents,is studied.It is coneluded that some surfactants,such as sodium bis-(2-ethylhexyl)sulfosuccinate(AOT)and isooctyl phenol polyethoxylate (TX-10),could form reverse micelles in supercritical carbon dioxide under the action of butanol.The formation of reverse micelles is a spontaneous process thermodynamically.Specifically for the nonionic surfactant TX-10,the formation of reverse micelles is dependent on the entropy increase in the system,while for the anionic surfactant AOT,the micellization is mainly dominated by the increase in enthalpy at higher temperatures,but by the increase in entropy at lower temperatures.

  9. Microwave Effect for Glycosylation Promoted by Solid Super Acid in Supercritical Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Takahiko Maeda

    2009-12-01

    Full Text Available The effects of microwave irradiation (2.45 GHz, 200 W on glycosylation promoted by a solid super acid in supercritical carbon dioxide was investigated with particular attention paid to the structure of the acceptor substrate. Because of the symmetrical structure and high diffusive property of supercritical carbon dioxide, microwave irradiation did not alter the temperature of the reaction solution, but enhanced reaction yield when aliphatic acceptors are employed. Interestingly, the use of a phenolic acceptor under the same reaction conditions did not show these promoting effects due to microwave irradiation. In the case of aliphatic diol acceptors, the yield seemed to be dependent on the symmetrical properties of the acceptors. The results suggest that microwave irradiation do not affect the reactivity of the donor nor promoter independently. We conclude that the effect of acceptor structure on glycosylation yield is due to electric delocalization of hydroxyl group and dielectrically symmetric structure of whole molecule.

  10. Enhanced metal recovery through oxidation in liquid and/or supercritical carbon dioxide

    KAUST Repository

    Blanco, Mario

    2017-08-24

    Process for enhanced metal recovery from, for example, metal-containing feedstock using liquid and/or supercritical fluid carbon dioxide and a source of oxidation. The oxidation agent can be free of complexing agent. The metal-containing feedstock can be a mineral such as a refractory mineral. The mineral can be an ore with high sulfide content or an ore rich in carbonaceous material. Waste can also be used as the metal-containing feedstock. The metal-containing feedstock can be used which is not subjected to ultrafine grinding. Relatively low temperatures and pressures can be used. The metal-containing feedstock can be fed into the reactor at a temperature below the critical temperature of the carbon dioxide, and an exotherm from the oxidation reaction can provide the supercritical temperature. The oxidant can be added to the reactor at a rate to maintain isothermal conditions in the reactor. Minimal amounts of water can be used as an extractive medium.

  11. Development of a Supercritical Carbon Dioxide Brayton Cycle: Improving PBR Efficiency and Testing Material Compatibility - 2004 Annual Report

    Energy Technology Data Exchange (ETDEWEB)

    Chang Oh; Thomas Lillo; William Windes; Terry Totemeier; Richard Moore

    2004-10-01

    The U.S. and other countries address major challenges related to energy security and the environmental impacts of fossil fuels. Solutions to these issues include carbon-free electricity generation and hydrogen production for fuel cell car, fertilizer synthesis, petroleum refining, and other applications. The Very High Temperature Gas Reactor (HTGR) has been recognized as a promising technology for high efficiency electricity generation and high temperature process heat applications. Therefore, the U.S. needs to make the HTGR intrinsically safe and proliferation-resistant. The U.S. and the world, however, must still overcome certain technical issues and the cost barrier before it can be built in the U.S. The establishment of a nuclear power cost goal of 3.3 cents/kWh is desirable in order to compete with fossil combined-cycle, gas turbine power generation. This goal requires approximately a 30% reduction in power cost for state-of-the-art nuclear plants. It has been demonstrated that this large cost differential can be overcome only by technology improvements that lead to a combination of better efficiency and more compatible reactor materials. The objectives of this research are (1) to develop a supercritical carbon dioxide Brayton cycle in the secondary power conversion side that can be applied to some Generation-IV reactors such as the HTGR and supercritical water reactor, (2) to improve the plant net efficiency by using the carbon dioxide Brayton cycle, and (3) to test material compatibility at high temperatures and pressures. The reduced volumetric flow rate of carbon dioxide due to higher density compared to helium will reduce compression work, which eventually increase turbine work enhancing the plant net efficiency.

  12. Generic supercritical water technology; Generic technology to shite no chorinkaisui riyo gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Arai, K.; Ajiri, M.; Inomata, H.; Smith, R.; Hakuta, Y. [Tohoku University, Sendai (Japan). Faculty of Engineering; Yokoyama, C. [Tohoku University, Sendai (Japan). The Institute forChemical Reaction Science; Chin, L. [New Energy and Industrial Technology Development Organization, Tokyo, (Japan)

    1997-02-01

    This paper describes the measurement and analysis for clarifying solution structure of supercritical water and exhibition mechanism of solvent functions. It also describes the development of new processes using supercritical water as reaction solvent. The PVT measurements were conducted in the supercritical region using pure water and NaCl aqueous solution, to confirm the reduction of molar volume of the electrolyte solution. The hydration structure was examined in the supercritical aqueous solution by the molecular dynamic simulation. As a result, presence of hydrogen bond structure, where the contribution of two branching hydrogen bond can not be ignored, was suggested under the supercritical condition. Characteristics of supercritical aqueous solutions are analyzed through in-situ Raman and scattered X-ray spectral measurements. Moreover, this paper introduces developments of some processes in the supercritical water, such as decomposition of wasted polymers, recovery of chemical materials, reforming of heavy hydrocarbons by contact hydrogenation, and synthesis of fine powders of metal oxide by reaction crystallization.

  13. Polyphenol-Retaining Decaffeinated Cocoa Powder Obtained by Supercritical Carbon Dioxide Extraction and Its Antioxidant Activity

    OpenAIRE

    Kinji Kobori; Yuto Maruta; Shigeru Mineo; Toru Shigematsu; Masao Hirayama

    2013-01-01

    Cocoa beans contain many functional ingredients such as theobromine and polyphenols, but also contain a relatively high amount of caffeine, which can negatively impact human health. It is therefore desirable to reduce caffeine levels in cocoa powder used to make chocolate or cocoa beverages while retaining functional ingredients. We have established conditions for supercritical carbon dioxide (SCCO2) extraction that remove 80.1% of the caffeine from cocoa powder while retaining theobromine (9...

  14. Separation of Erucic Acid from Rape-Seed Oil Using Supercritical Carbon Dioxide with Entrainer

    Institute of Scientific and Technical Information of China (English)

    云志; 钱仁渊; 等

    2002-01-01

    Separation of erucic acid from rape-seed oil using supercritical carbon dioxide with entrainer was carried on a pilot column with an inner diameter 14 mm and an effective total height 2.2m.Experiments were focused on the effects of entrainers.i.e.acetone.ethanol and ethyl acetate,on the extraction.It is showed that entrainers made selectivity lower,but separation time shorter.

  15. Supercritical Fluid Carbon Dioxide in the Extraction of Lanolin and Its Alcohol

    Institute of Scientific and Technical Information of China (English)

    林苗; 陈小立; 杨勇

    2003-01-01

    The use of supercritical fluid carbon dioxide (SFCO2) in extraction of lanolin and its alcohol is superior to the conventional solvent extraction method. Its distinctive advantages include high extractive ratio, nontoxic and nonflammable solvents, and minimal by -product pollution. The resulting refined lanolin and its alcohol have light color and little odor, and can be used as raw materials for high grade cosmetic products.

  16. One Step Preparation of Controlled Drug Release Systems in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    CAO Liqin; WANG Chengwei; CHEN Liuping

    2009-01-01

    Drug delivery systems based on copolymers of N-isopropylacrylamide were fn-st prepared by a one step method, in which supercritical carbon dioxide was simultaneously used as a polymerization medium and an impregnation agent. The obtained microspheres were characterized by scanning electronic microscopy (SEM), differential scan-ning calorimetry (DSC), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The release effect of the in situ prepared microgels impregnated with ibuprofen was presented through in vitro release simulation.

  17. Efficiency of water removal from water/ethanol mixtures using supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    M. A. Rodrigues

    2006-06-01

    Full Text Available Techniques involving supercritical carbon dioxide have been successfully used for the formation of drug particles with controlled size distributions. However, these processes show some limitations, particularly in processing aqueous solutions. A diagram walking algorithm based on available experimental data was developed to evaluate the effect of ethanol on the efficiency of water removal processes under different process conditions. Ethanol feeding was the key parameter resulting in a tenfold increase in the efficiency of water extraction.

  18. Solubility and Phase Behavior of CL20 and RDX in Supercritical Carbon Dioxide

    Science.gov (United States)

    2004-12-01

    can be evaluated using a cubic equation of state such as the Redlich - Kwong -Soave or the Peng-Robinson equations. In this work, the Peng-Robinson...biphenyl in supercritical carbon dioxide. The applicability of the estimation techniques employed for the critical properties for CL20 was established...25, 326. Modell, M., Reid, R.C., 1983, Thermodynamics and Its Applications , (2nd ed., Prentice Hall Publishing, Englewood Cliffs, NJ). Morris

  19. Amino Acid Synthesis in a Supercritical Carbon Dioxide - Water System

    Directory of Open Access Journals (Sweden)

    Akiyoshi Hoshino

    2009-06-01

    Full Text Available Mars is a CO2-abundant planet, whereas early Earth is thought to be also CO2-abundant. In addition, water was also discovered on Mars in 2008. From the facts and theory, we assumed that soda fountains were present on both planets, and this affected amino acid synthesis. Here, using a supercritical CO2/liquid H2O (10:1 system which mimicked crust soda fountains, we demonstrate production of amino acids from hydroxylamine (nitrogen source and keto acids (oxylic acid sources. In this research, several amino acids were detected with an amino acid analyzer. Moreover, alanine polymers were detected with LC-MS. Our research lights up a new pathway in the study of life’s origin.

  20. Antimicrobial Cream Formulated with Supercritical Carbon Dioxide Extract of Tuberose Flowers Arrests Growth of Staphylococcus aureus.

    Science.gov (United States)

    Ghosh, Probir Kumar; Bhattacharjee, Paramita; Das, Satadal

    2016-01-01

    Antimicrobial potency of herbal extracts is well known. The review of patents and research articles revealed that several herbal extracts have been employed in the formulation of topical products such as creams, exclusive of the cream reported in the present study. 0ur previous study has established antimicrobial potency of supercritical carbon dioxide extracts of tuberose flowers, better known for its sweet fragrance. The present work focuses on formulating a topical antimicrobial herbal cream with methyl eugenol (principal antimicrobial compound) rich - supercritical carbon dioxide extract of tuberose flowers, having good combination of phytochemical and antimicrobial potencies. Supercritical carbon dioxide parameters such as temperature, pressure and time were optimized using full factorial experimental design to obtain methyl eugenol-rich extracts. A cream was formulated using the extract having the best combination of phytochemical and antimicrobial potencies and was assayed further for in vitro antimicrobial potency; physiochemical and sensory properties. Two commercial antimicrobial cream samples were used as reference samples in the study. The extract obtained at 40°C, 10 MPa, 135 min at 1 L min-1 flow rate of gaseous C02 showed the best combination of phytochemical and antimicrobial potencies and was used for formulation of herbal creams. The cream formulated with 5% w/w of extract arrested growth of the common human skin pathogen Staphylococcus aureus and showed stable physiochemical properties and high sensory appeal for a year. The cream could be considered as a 'finished herbal product&' in compliance with the World Health 0rganization guidelines.

  1. A review of enzymatic transesterification of microalgal oil-based biodiesel using supercritical technology.

    Science.gov (United States)

    Taher, Hanifa; Al-Zuhair, Sulaiman; Al-Marzouqi, Ali H; Haik, Yousef; Farid, Mohammed M

    2011-01-01

    Biodiesel is considered a promising replacement to petroleum-derived diesel. Using oils extracted from agricultural crops competes with their use as food and cannot realistically satisfy the global demand of diesel-fuel requirements. On the other hand, microalgae, which have a much higher oil yield per hectare, compared to oil crops, appear to be a source that has the potential to completely replace fossil diesel. Microalgae oil extraction is a major step in the overall biodiesel production process. Recently, supercritical carbon dioxide (SC-CO(2)) has been proposed to replace conventional solvent extraction techniques because it is nontoxic, nonhazardous, chemically stable, and inexpensive. It uses environmentally acceptable solvent, which can easily be separated from the products. In addition, the use of SC-CO(2) as a reaction media has also been proposed to eliminate the inhibition limitations that encounter biodiesel production reaction using immobilized enzyme as a catalyst. Furthermore, using SC-CO(2) allows easy separation of the product. In this paper, conventional biodiesel production with first generation feedstock, using chemical catalysts and solvent-extraction, is compared to new technologies with an emphasis on using microalgae, immobilized lipase, and SC-CO(2) as an extraction solvent and reaction media.

  2. A Review of Enzymatic Transesterification of Microalgal Oil-Based Biodiesel Using Supercritical Technology

    Science.gov (United States)

    Taher, Hanifa; Al-Zuhair, Sulaiman; Al-Marzouqi, Ali H.; Haik, Yousef; Farid, Mohammed M.

    2011-01-01

    Biodiesel is considered a promising replacement to petroleum-derived diesel. Using oils extracted from agricultural crops competes with their use as food and cannot realistically satisfy the global demand of diesel-fuel requirements. On the other hand, microalgae, which have a much higher oil yield per hectare, compared to oil crops, appear to be a source that has the potential to completely replace fossil diesel. Microalgae oil extraction is a major step in the overall biodiesel production process. Recently, supercritical carbon dioxide (SC-CO2) has been proposed to replace conventional solvent extraction techniques because it is nontoxic, nonhazardous, chemically stable, and inexpensive. It uses environmentally acceptable solvent, which can easily be separated from the products. In addition, the use of SC-CO2 as a reaction media has also been proposed to eliminate the inhibition limitations that encounter biodiesel production reaction using immobilized enzyme as a catalyst. Furthermore, using SC-CO2 allows easy separation of the product. In this paper, conventional biodiesel production with first generation feedstock, using chemical catalysts and solvent-extraction, is compared to new technologies with an emphasis on using microalgae, immobilized lipase, and SC-CO2 as an extraction solvent and reaction media. PMID:21915372

  3. Recovery of cobalt from spent lithium-ion batteries using supercritical carbon dioxide extraction.

    Science.gov (United States)

    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%.

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

    Science.gov (United States)

    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 CO2 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 CO2 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 CO2 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 CO2 dyeing technique.

  5. Recycling high-performance carbon fiber reinforced polymer composites using sub-critical and supercritical water

    Science.gov (United States)

    Knight, Chase C.

    Carbon fiber reinforced plastics (CFRP) are composite materials that consist of carbon fibers embedded in a polymer matrix, a combination that yields materials with properties exceeding the individual properties of each component. CFRP have several advantages over metals: they offer superior strength to weight ratios and superior resistance to corrosion and chemical attack. These advantages, along with continuing improvement in manufacturing processes, have resulted in rapid growth in the number of CFRP products and applications especially in the aerospace/aviation, wind energy, automotive, and sporting goods industries. Due to theses well-documented benefits and advancements in manufacturing capabilities, CFRP will continue to replace traditional materials of construction throughout several industries. However, some of the same properties that make CFRP outstanding materials also pose a major problem once these materials reach the end of service life. They become difficult to recycle. With composite consumption in North America growing by almost 5 times the rate of the US GDP in 2012, this lack of recyclability is a growing concern. As consumption increases, more waste will inevitably be generated. Current composite recycling technologies include mechanical recycling, thermal processing, and chemical processing. The major challenge of CFRP recycling is the ability to recover materials of high-value and preserve their properties. To this end, the most suitable technology is chemical processing, where the polymer matrix can be broken down and removed from the fiber, with limited damage to the fibers. This can be achieved using high concentration acids, but such a process is undesirable due to the toxicity of such materials. A viable alternative to acid is water in the sub-critical and supercritical region. Under these conditions, the behavior of this abundant and most environmentally friendly solvent resembles that of an organic compound, facilitating the breakdown

  6. Generation of Microcellular Biodegradable Polycaprolactone Foams in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    Xu Qun; Ren Xian-wen; Chang Yu-ning; Yu Long; Wang Jing-wu

    2004-01-01

    Present now the application of microcellular polymeric materials in biomedical field is growing rapidly, as that of guided tissue regeneration and cell transplantation. As far as guided tissue regeneration is concerned, porous implants are used as size selective membrane to promote the growth of a special tissue in a healing site. Ideally, the implant should be inherently biocompatible,have well-defined cell size and be resorbable with appropriate biodegradation rates.Poly(a-caprolactone) (PCL) is a kind of materials suit for the demands above. PCL is biocompatible and biodegradable aliphatic polyester which is nontoxic for living organisms and bioresorbable after a period of implantation. Because of its unique combination of biocompatibility, permeability and biodegradability, PCL and some of its copolymer with lactides and glycolide have been widely applied in medicine as artificial skin, artificial bone and containers for sustained drug release.Goel and Beckman have reported a new method to generate microcellular poly(methy l methacrylate) foams in which the samples are saturated with CO2 under a series of supercritical (SC)conditions, and then the system is rapidly depressurized to atmospheric pressure at constant temperature. Unlike traditional methods, it reduces glass-transition temperature (Tg) of the mixture to below the experimental temperature rather than directly heat the system above Tg. In this process of nucleation, no phase separation occurs as well as no phase boundary meets, so the cellular structure of the foam can be retained better.In this work, we have generated PCL foams by using supercritical CO2. Because of the low glass transition temperature (Tg = -60 ℃) of PCL far below the ice point, the experimental temperature in our study is much higher than Tg, which is different from the studies by others before. A series of variable factors on the foam structure as saturation temperature, saturation pressure, saturation time and depressurization

  7. Supercritical Carbon Dioxide and Microwave-Assisted Extraction of Functional Lipophilic Compounds from Arthrospira platensis

    Directory of Open Access Journals (Sweden)

    Diego A. Esquivel-Hernández

    2016-05-01

    Full Text Available Arthrospira platensis biomass was used in order to obtain functional lipophilic compounds through green extraction technologies such as supercritical carbon dioxide fluid extraction (SFE and microwave-assisted extraction (MAE. The temperature (T factor was evaluated for MAE, while for SFE, pressure (P, temperature (T, and co-solvent (ethanol (CS were evaluated. The maximum extraction yield of the obtained oleoresin was (4.07% ± 0.14% and (4.27% ± 0.10% for SFE and MAE, respectively. Extracts were characterized by gas chromatography mass spectrometry (GC-MS and gas chromatography flame ionization detector (GC-FID. The maximum contents of functional lipophilic compounds in the SFE and MAE extracts were: for carotenoids 283 ± 0.10 μg/g and 629 ± 0.13 μg/g, respectively; for tocopherols 5.01 ± 0.05 μg/g and 2.46 ± 0.09 μg/g, respectively; and for fatty acids 34.76 ± 0.08 mg/g and 15.88 ± 0.06 mg/g, respectively. In conclusion, the SFE process at P 450 bar, T 60 °C and CS 53.33% of CO2 produced the highest yield of tocopherols, carotenoids and fatty acids. The MAE process at 400 W and 50 °C gives the best extracts in terms of tocopherols and carotenoids. For yield and fatty acids, the MAE process at 400 W and 70 °C produced the highest values. Both SFE and MAE showed to be suitable green extraction technologies for obtaining functional lipophilic compounds from Arthrospira platensis.

  8. Supercritical Carbon Dioxide and Microwave-Assisted Extraction of Functional Lipophilic Compounds from Arthrospira platensis

    Science.gov (United States)

    Esquivel-Hernández, Diego A.; López, Víctor H.; Rodríguez-Rodríguez, José; Alemán-Nava, Gibrán S.; Cuéllar-Bermúdez, Sara P.; Rostro-Alanis, Magdalena; Parra-Saldívar, Roberto

    2016-01-01

    Arthrospira platensis biomass was used in order to obtain functional lipophilic compounds through green extraction technologies such as supercritical carbon dioxide fluid extraction (SFE) and microwave-assisted extraction (MAE). The temperature (T) factor was evaluated for MAE, while for SFE, pressure (P), temperature (T), and co-solvent (ethanol) (CS) were evaluated. The maximum extraction yield of the obtained oleoresin was (4.07% ± 0.14%) and (4.27% ± 0.10%) for SFE and MAE, respectively. Extracts were characterized by gas chromatography mass spectrometry (GC-MS) and gas chromatography flame ionization detector (GC-FID). The maximum contents of functional lipophilic compounds in the SFE and MAE extracts were: for carotenoids 283 ± 0.10 μg/g and 629 ± 0.13 μg/g, respectively; for tocopherols 5.01 ± 0.05 μg/g and 2.46 ± 0.09 μg/g, respectively; and for fatty acids 34.76 ± 0.08 mg/g and 15.88 ± 0.06 mg/g, respectively. In conclusion, the SFE process at P 450 bar, T 60 °C and CS 53.33% of CO2 produced the highest yield of tocopherols, carotenoids and fatty acids. The MAE process at 400 W and 50 °C gives the best extracts in terms of tocopherols and carotenoids. For yield and fatty acids, the MAE process at 400 W and 70 °C produced the highest values. Both SFE and MAE showed to be suitable green extraction technologies for obtaining functional lipophilic compounds from Arthrospira platensis. PMID:27164081

  9. Biodiesel Production Using Supercritical Methanol with Carbon Dioxide and Acetic Acid

    Directory of Open Access Journals (Sweden)

    Chao-Yi Wei

    2013-01-01

    Full Text Available Transesterification of oils and lipids in supercritical methanol is commonly carried out in the absence of a catalyst. In this work, supercritical methanol, carbon dioxide, and acetic acid were used to produce biodiesel from soybean oil. Supercritical carbon dioxide was added to reduce the reaction temperature and increase the fats dissolved in the reaction medium. Acetic acid was added to reduce the glycerol byproduct and increase the hydrolysis of fatty acids. The Taguchi method was used to identify optimal conditions in the biodiesel production process. With an optimal reaction temperature of 280°C, a methanol-to-oil ratio of 60, and an acetic acid-to-oil ratio of 3, a 97.83% yield of fatty acid methyl esters (FAMEs was observed after 90 min at a reaction pressure of 20 MPa. While the common approach to biodiesel production results in a glycerol byproduct of about 10% of the yield, the practices reported in this research can reduce the glycerol byproduct by 30.2% and thereby meet international standards requiring a FAME content of >96%.

  10. Microcellular foaming of silicone rubber with supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Hong, In-Kwon; Lee, Sangmook [Dankook University, Youngin (Korea, Republic of)

    2014-01-15

    In spite of great concern on the industrial application of microcellular silicone rubber foams, such as in electric and medical devices, only a few works can be found about the foaming of silicone rubber. In this study, microcellular silicone rubber foams with a cell size of 12 µm were successfully prepared with curing by heat and foaming by supercritical CO{sub 2} as a green blowing agent. The microcellular silicone rubber foams exhibited a well-defined cell structure and a uniform cell size distribution. The crosslinking and foaming of silicone rubber was carried out separately. After foaming, the silicone rubber foam was cross-linked again to stabilize the foam structure and further improve its mechanical properties. Foaming process of cross-linked silicone rubber should be designed carefully based on the viscoelastic properties because of its elastic volume recovery in the atmosphere. The basic crosslinking condition for small cell size and high cell density was obtained after investigating the rheological behavior during crosslinking.

  11. Solubility of Paclitaxel in Mixtures of Dichloromethane and Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    LUO Nin; LU Yingmei; JIANG Yanbin

    2011-01-01

    Phase behavior of paclitaxel in solvent mixtures of dichloromethane and supercritical carbon dioxide was investigated using a supercritical phase monitor.Cloud point pressures were determined as a function of temperature,pressure and paclitaxel content from 313.1 to 343.1K and pressures up to 33.52 MPa.The ternary mixtures exhibit a typical lower critical solution temperature behavior.When paclitaxel content increases,the single-phase region shrinks in size.Three cubic equations of state(Redlich-Kworng,Soave-Redlich-Kwong and Peng-Robinson equation of state) coupled with the van der Waals one-fluid mixing rules were selected to correlate the experimental data.The results indicate that SRK EOS coupled with two binary interaction parameters kij and lij can predict paclitaxel solubility for the best fit of experimental data.

  12. Extraction of essential oil from Pimpinella anisum using supercritical carbon dioxide and comparison with hydrodistillation.

    Science.gov (United States)

    Yamini, Yadollah; Bahramifar, Nader; Sefidkon, Fatemeh; Saharkhiz, Mohamad Jamal; Salamifar, Ehsan

    2008-02-15

    Supercritical fluid extraction (SFE) of essential oil from Pimpinella anisum, using carbon dioxide as a solvent is presented in this work. An orthogonal array design OA9 (3(4)) was applied to select the optimum extraction condition. The effects of pressure, temperature, dynamic extraction time and methanol volume on the extraction efficiency were investigated by the three-level orthogonal array design. Results show that pressure has a significant effect on the extraction efficiency. The extract obtained from P. anisum by using supercritical fluid extraction was compared with the essential oil obtained by hydrodistillation, considering both quantity and quality of the product. SFE products were found to be of markedly different composition, compared with the corresponding hydrodistilated oil. The total amount of extractable substances obtained in SFE (7.5%) is higher than that obtained by hydrodistillation (3.1%) and SFE is faster than hydrodistillation method.

  13. Purification of Single-Wall carbon nanotubes by heat treatment and supercritical extraction

    Directory of Open Access Journals (Sweden)

    Mariana Bertoncini

    2011-09-01

    Full Text Available Arc discharge is the most practical method for the synthesis of single wall carbon nanotubes (SWCNT. However, the production of SWCNT by this technique has low selectivity and yield, requiring further purification steps. This work is a study of purification of SWCNT by heat treatment in an inert atmosphere followed by supercritical fluid extraction. The raw arc discharge material was first heat-treated at 1250 °C under argon. The nanotubes were further submitted to an extraction process using supercritical CO2 as solvent. A surfactant (tributylphosphate, TBP and a chelating agent (hexafluoroacetylacetone, HFA were used together to eliminate metallic impurities from the remaining arc discharge catalysts. Analysis of Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES showed an efficient removal of iron and cobalt (>80%. The purified nanotubes were further analyzed by TGA and Raman spectroscopy.

  14. A supercritical fluid-based coating technology. 2: solubility considerations.

    Science.gov (United States)

    Ribeiro Dos Santos, I; Thies, C; Richard, J; Le Meurlay, D; Gajan, V; VandeVelde, V; Benoit, J-P

    2003-01-01

    Solubility measurements of candidate coating materials have been performed in supercritical (SC) CO(2) so as to select appropriate coating materials for implementation of a solvent-free coating process previously described. Solubility of lipidic compounds such as waxes (paraffin, beeswax, Carnauba wax), pure triglycerides (tricaprin, trimyristin, tripalmitin, tristearin) and mixture of glycerides and fatty acid esters (Gelucire) in SC CO(2) were evaluated in a static mode under different temperature and pressure conditions, ranging from 13-52 degrees C and from 50-220 bar, whether the CO(2)was in its liquid or SC state. It was shown that the compounds which are mixtures of various components give rise to a selective extraction of the lower melting point components, as evidenced from thermal analysis of soluble and insoluble fractions of the coating materials.

  15. Glycerol conversion into value added chemicals over bimetallic catalysts in supercritical carbon dioxide

    Science.gov (United States)

    Hidayati, Luthfiana N.; Sudiyarmanto, Adilina, Indri B.

    2017-01-01

    Development of alternative energy from biomass encourage the experiments and production of biodiesel lately. Biodiesel industries widely expand because biodiesel as substitute of fossil fuel recognized as promising renewable energy. Glycerol is a byproduct of biodiesel production, which is resulted 10% wt average every production. Meanwhile, carbon dioxide is a gas that is very abundant amount in the atmosphere. Glycerol and carbon dioxide can be regarded as waste, possibly will produce value-added chemical compounds through chemically treated. In this preliminary study, conversion of glycerol and carbon dioxide using bimetallic catalyst Ni-Sn with various catalyst supports : MgO, γ-Al2O3, and hydrotalcite. Catalysts which have been prepared, then physically characterized by XRD, surface area and porosity analysis, and thermal gravity analysis. Catalytic test performance using supercritical carbon dioxide conditions. Furthermore, the products were analyzed by GC. The final product mostly contained of propylene glycol and glycerol carbonate.

  16. Fischer-Tropsch synthesis in supercritical phase carbon dioxide: Recycle rates

    Science.gov (United States)

    Soti, Madhav

    With increasing oil prices and attention towards the reduction of anthropogenic CO2, the use of supercritical carbon dioxide for Fischer Tropsch Synthesis (FTS) is showing promise in fulfilling the demand of clean liquid fuels. The evidence of consumption of carbon dioxide means that it need not to be removed from the syngas feed to the Fischer Tropsch reactor after the gasification process. Over the last five years, research at SIUC have shown that FTS in supercritical CO2reduces the selectivities for methane, enhances conversion, reduces the net CO2produces in the coal to liquid fuels process and increase the life of the catalyst. The research has already evaluated the impact of various operating and feed conditions on the FTS for the once through process. We believe that the integration of unreacted feed recycle would enhance conversion, increase the yield and throughput of liquid fuels for the same reactor size. The proposed research aims at evaluating the impact of recycle of the unreacted feed gas along with associated product gases on the performance of supercritical CO2FTS. The previously identified conditions will be utilized and various recycle ratios will be evaluated in this research once the recycle pump and associated fittings have been integrated to the supercritical CO2FTS. In this research two different catalysts (Fe-Zn-K, Fe-Co-Zn-K) were analyzed under SC-FTS in different recycle rate at 350oC and 1200 psi. The use of recycle was found to improve conversion from 80% to close to 100% with both catalysts. The experiment recycle rate at 4.32 and 4.91 was clearly surpassing theoretical recycle curve. The steady state reaction rate constant was increased to 0.65 and 0.8 min-1 for recycle rate of 4.32 and 4.91 respectively. Carbon dioxide selectivity was decreased for both catalyst as it was converting to carbon monoxide. Carbon dioxide consumption was increased from 0.014 to 0.034 mole fraction. This concluded that CO2is being used in the system and

  17. The Analysis of Activated Carbon Regeneration Technologies

    Institute of Scientific and Technical Information of China (English)

    姚芳

    2014-01-01

    A series of methods for activated carbon regeneration were briefly introduced.Such as thermal regeneration,chemical regeneration,biochemical regeneration,and newly supercritical fluid regeneration, electrochemical regeneration,light-catalyzed regeneration,and microwave radiation method,and the developing trend of activated carbon regeneration was predicted.

  18. THE PHASE BEHAVIOR OF FLUORINATED DIOLS, DIVINYL ADIPATE, AND A FLUORINATED POLYESTER IN SUPERCRITICAL CARBON DIOXIDE. (R828131)

    Science.gov (United States)

    The use of supercritical carbon dioxide as a reaction medium for polyester synthesis is hindered by the low solubility of diols in CO2. However, it has been previously demonstrated that fluorinated compounds can exhibit greater miscibility with carbon dioxide than t...

  19. Extraction of betulin from bark of Betula platyphylla by supercritical carbon dioxide extraction

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yu-hong; YU Tao; WANG Yang

    2003-01-01

    Betulin, which is a medicinal pentacyclic triterpene, is abundant in the bark of white birch (Betula platyphlly). The bark of birch was collected at Tayuan Forest Farm of Jiagedaqi, Heilongjiang Province in September 2000. Supercritical fluid extraction (SFE) that is a new separation technology has been used for the processing pharmaceutical and natural products. In this paper, the extraction of betulin from the bark of birch by supercritical CO2 extraction was studied. The authors investigated and analyzed a few parameters such as modifier dosage, extraction pressure and extraction temperature. The optimal extraction conditions showed that the modifier dosage used for per gram bark powder was 1.5 mL, the extraction pressure was at 20 Mpa, and the extraction temperature was at 55 ℃. The velocity of flow of liquid CO2 was at 10 kg/h. The pressure and temperature in separation vessel were at 5.5 Mpa and 50 ℃, respectively.

  20. Phase Equilibria Measurement of Binary Mixture for the Propoxylated Neopentyl Glycol Diacrylate in Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Hun-Soo [Chonnam National University, Yeosu (Korea, Republic of)

    2016-04-15

    Experimental data are reported on the phase equilibrium of propoxylated neopentyl glycol diacrylate in supercritical carbon dioxide. Phase equilibria data were measured in static method at a temperature of (313.2, 333.2, 353.2, 373.2 and 393.2) K and at pressures up to 27.82 MPa. At a constant pressure, the solubility of propoxylated neopentyl glycol diacrylate for the (carbon dioxide + propoxylated neopentyl glycol diacrylate) system increases as temperature increases. The (carbon dioxide + propoxylated neopentyl glycol diacrylate) system exhibits type-I phase behavior. The experimental result for the (carbon dioxide + propoxylated neopentyl glycol diacrylate) system is correlated with Peng- Robinson equation of state using mixing rule. The critical property of propoxylated neopentyl glycol diacrylate is predicted with Joback and Lyderson method.

  1. Numerical Comparison of Thermalhydraulic Aspects of Supercritical Carbon Dioxide and Subcritical Water-Based Natural Circulation Loop

    Directory of Open Access Journals (Sweden)

    Milan Krishna Singha Sarkar

    2017-02-01

    Full Text Available Application of the supercritical condition in reactor core cooling needs to be properly justified based on the extreme level of parameters involved. Therefore, a numerical study is presented to compare the thermalhydraulic performance of supercritical and single-phase natural circulation loops under low-to-intermediate power levels. Carbon dioxide and water are selected as respective working fluids, operating under an identical set of conditions. Accordingly, a three-dimensional computational model was developed, and solved with an appropriate turbulence model and equations of state. Large asymmetry in velocity and temperature profiles was observed in a single cross section due to local buoyancy effect, which is more prominent for supercritical fluids. Mass flow rate in a supercritical loop increases with power until a maximum is reached, which subsequently corresponds to a rapid deterioration in heat transfer coefficient. That can be identified as the limit of operation for such loops to avoid a high temperature, and therefore, the use of a supercritical loop is suggested only until the appearance of such maxima. Flow-induced heat transfer deterioration can be delayed by increasing system pressure or lowering sink temperature. Bulk temperature level throughout the loop with water as working fluid is higher than supercritical carbon dioxide. This is until the heat transfer deterioration, and hence the use of a single-phase loop is prescribed beyond that limit.

  2. Numerical comparison of thermal hydraulic aspects of supercritical carbon dioxide and subcritical water-based natural circulation loop

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, Milan Krishna Singhar; Basu, Dipankar Narayan [Dept. of Mechanical Engineering, Indian Institute of Technology Guwahati, Guwahati (India)

    2017-02-15

    Application of the supercritical condition in reactor core cooling needs to be properly justified based on the extreme level of parameters involved. Therefore, a numerical study is presented to compare the thermalhydraulic performance of supercritical and single-phase natural circulation loops under low-to-intermediate power levels. Carbon dioxide and water are selected as respective working fluids, operating under an identical set of conditions. Accordingly, a three-dimensional computational model was developed, and solved with an appropriate turbulence model and equations of state. Large asymmetry in velocity and temperature profiles was observed in a single cross section due to local buoyancy effect, which is more prominent for supercritical fluids. Mass flow rate in a supercritical loop increases with power until a maximum is reached, which subsequently corresponds to a rapid deterioration in heat transfer coefficient. That can be identified as the limit of operation for such loops to avoid a high temperature, and therefore, the use of a supercritical loop is suggested only until the appearance of such maxima. Flow-induced heat transfer deterioration can be delayed by increasing system pressure or lowering sink temperature. Bulk temperature level throughout the loop with water as working fluid is higher than supercritical carbon dioxide. This is until the heat transfer deterioration, and hence the use of a single-phase loop is prescribed beyond that limit.

  3. New dimension of slow food movement using supercritical fluid technology and methods to influence society by effective marketing strategies.

    Science.gov (United States)

    Uzel, Ruhan Aşkın

    2016-07-01

    Although slow food movement is a well-known movement nowadays, in order to make it more widespread to the society, necessity to develop and to adapt new techniques has become inevitable for healthier consumption age. For this purpose, possibility of increased usage of healthy foods with addition of natural extracts using new techniques came out from relevant questionaries applied to people of different age groups. In this study, specific properties of supercritical carbon dioxide at distinct temperatures and water in subcritical conditions were used to obtain extracts rich in water-soluble organic compounds. Experiments were carried out at pressures of 10, 20, 30, and 40 MPa and temperatures ranging from 40 to 200 ℃ with and without modifier for 2 h of extraction time. The flow rate was kept at 4 and 1 ml/min for CO2 and water, respectively. The highest water-soluble organic compound recovery yield was 78.10%. Results were supported by marketing strategies to announce this new application and products to the society. Group of sample questions was prepared to investigate (a) frequency of staple food usage, (b) the brand names and relevant reasons that bring up consumers to buy specifically same branded products, (c) knowledge about the ingredients and how advertising effects purchasing decision, etc. Finally, efficiency increase in slow food consumption was proved with supercritical fluid technology to draw attention to the health of consumers with newer and functional healthy foods. © The Author(s) 2015.

  4. Experimental study on heat transfer of supercritical carbon dioxide in a long silica-based porous-media tube

    Science.gov (United States)

    Hsieh, Jui-Ching; Lin, David T. W.; Lee, Bo-Heng; Chung, Ming-Che

    2017-03-01

    The heat transfer phenomena of supercritical carbon dioxide were experimentally investigated in a vertical tube containing silica-based porous media. The experiment was conducted at various levels of static pressure, flow rates, and initial wall temperatures as well as with silica sand of porous media in a long test section to study the heat transfer characteristics of supercritical carbon dioxide (CO2). The results indicated that the average heat transfer coefficient and outlet temperature at an initial wall temperature of 150 °C were higher and lower than that of 200 °C. The heat transfer performance was significantly influenced by flow rate of supercritical CO2. The porous media was provided large heat exchange surface between particles and CO2 to increase the heat transfer coefficient, especially when small diameter of particles. When the inlet temperature was higher than the pseudocritical temperature, the heat transfer coefficient sharply dropped when x/L ≥ 0.5, because of the development of a thermal boundary and the decrease of CO2 thermophysical properties of CO2 in a far pseudocritical temperature. When the pseudocritical temperature was higher than the inlet temperature of the fluid, the local heat transfer coefficient was affected by a thermal boundary and thermophysical properties of CO2 in pseudocritical point at a higher initial wall temperature or lower supercritical pressure when x/L ≤ 0.75; only the thermophysical properties of supercritical CO2 in pseudocritical point played a pivotal role when x/L > 0.75 at a lower initial wall temperature or higher supercritical pressure. In the present study, the supercritical pressure of 10.5 MPa constituted an optimal operating condition for supercritical CO2 a long silica-based porous-media tube because of the high heat transfer performance at 150 and 200 °C.

  5. Supercritical carbon dioxide extraction of oil from Clanis bilineata ...

    African Journals Online (AJOL)

    AJL

    2012-02-16

    % (w/w) of ... carbon dioxide extraction method (Model: HA 420-40-96, Jiangsu. Huaan Scientific ... pressure, 25 MPa; temperature, 35°C and time, 60 min. ... The organic layer was dried over anhydrous Na2SO4. The fatty acid.

  6. Antifeedant activity of xanthohumol and supercritical carbon dioxide extract of spent hops against stored product pests.

    Science.gov (United States)

    Jackowski, J; Hurej, M; Rój, E; Popłoński, J; Kośny, L; Huszcza, E

    2015-08-01

    Xanthohumol, a prenylated flavonoid from hops, and a supercritical carbon dioxide extract of spent hops were studied for their antifeedant activity against stored product insect pests: Sitophilus granarius L., Tribolium confusum Duv. and Trogoderma granarium Everts. Xanthohumol exhibited medium deterrent activity against the adults of S. granarius L. and larvae of T. confusum Duv. The spent hops extract was more active than xanthohumol towards the adults of T. confusum Duv. The potential application of the crude spent hops extract as a feeding deterrent against the stored product pests is proposed.

  7. Continuous reactions in supercritical carbon dioxide: problems, solutions and possible ways forward.

    Science.gov (United States)

    Han, Xue; Poliakoff, Martyn

    2012-02-21

    This Tutorial Review focuses on supercritical carbon dioxide (scCO(2)), and discusses some of the problems that have frustrated its wide use on an industrial scale. It gives some recent examples where strategies have been developed to reduce the energy requirements, including sequential reactions and gas-expanded liquids. It then describes a number of cases where scCO(2) offers real chemical advantages over more conventional solvents, for example by controlled phase separation, tunable selectivity, oxidation and on-line analysis and self-optimisation. Overall, this review indicates where scCO(2) could deliver value in the future.

  8. Task Order 20: Supercritical Carbon Dioxide Brayton Cycle Energy Conversion Study

    Energy Technology Data Exchange (ETDEWEB)

    Murray, Paul [AREVA Federal Services, LLC, Charlotte, NC (United States); Lindsay, Edward [AREVA Federal Services, LLC, Charlotte, NC (United States); McDowell, Michael [AREVA Federal Services, LLC, Charlotte, NC (United States); Huang, Megan [AREVA Federal Services, LLC, Charlotte, NC (United States)

    2015-04-23

    AREVA Inc. developed this study for the US Department of Energy (DOE) office of Nuclear Energy (NE) in accordance with Task Order 20 Statement of Work (SOW) covering research and development activities for the Supercritical Carbon Dioxide (sCO2) Brayton Cycle energy conversion. The study addresses the conversion of sCO2 heat energy to electrical output by use of a Brayton Cycle system and focuses on the potential of a net efficiency increase via cycle recuperation and recompression stages. The study also addresses issues and study needed to advance development and implementation of a 10 MWe sCO2 demonstration project.

  9. Glycerol Dehydration to Acrolein Catalyzed by ZSM‐5 Zeolite in Supercritical Carbon Dioxide Medium

    Science.gov (United States)

    Zou, Bin; Ren, Shoujie

    2016-01-01

    Abstract Supercritical carbon dioxide (SC‐CO2) has been used for the first time as a reaction medium for the dehydration of glycerol to acrolein catalyzed by a solid acid. Unprecedented catalyst stability over 528 hours of time‐on‐stream was achieved and the rate of coke deposition on the zeolite catalyst was the lowest among extensive previous studies, showing potential for industrial application. Coking pathways in SC‐CO2 were also elucidated for future development. The results have potential implications for other dehydration reactions catalyzed by solid acids. PMID:27796088

  10. Effect of pressure of supercritical carbon dioxide on morphology of wool fibers during dyeing process

    Directory of Open Access Journals (Sweden)

    Zheng Lai-Jiu

    2015-01-01

    Full Text Available In this paper, the effect of pressure release rate on dyeing of wool fibers was studied in the supercritical carbon dioxide dyeing. Surface morphology, chemical composition and color difference at different pressure release rates were investigated by employing scanning electron microscope, color matching, and measuring instrument. Experiment data reveal that wool fibers are easy to be damaged with increasing pressure release rate. Fiber’s surface brightness varies also with the pressure release rate. The phenomena are theoretically explained using Bernoulli's principle.

  11. Study on the Phase Behavior of Coating Matrix in Supercritical or Sub—critical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    曹维良; 徐金龙; 张敬畅

    2003-01-01

    The high-pressure phase behavior of coating -solvent-supercritical or sub-critical carbon dioxide system was investigated experimentally.The coating matrix used was 108-acrylic resin at concentration raging from 10% to 50%(by mass) in mixtures with n-butyl acetate ,The experiments were conducted in a high-pressure view cell for temperatures from 35℃to 65 ℃ and for pressures from 3.0 MPa to 8.0 MPa ,The effect of temperature,pressure and content of every component on the phase behavior of the systems was observed,Finally ,the ternary phase diagram for resin-solvent-CO2 was plotted.

  12. Carbon Farming as a Carbon Negative Technology

    Science.gov (United States)

    Anderson, C.; Laird, D.; Hayes, D. J.

    2015-12-01

    Carbon farms have a pivotal role in national and international efforts to mitigate and adapt to climate change. A carbon farm in its broadest sense is one that reduces greenhouse gas (GHG) emissions or captures and holds carbon in vegetation and soils. Their capacity to remove carbon from the air and store it safely and permanently, while providing additional human and ecosystem benefits, means they could contribute significantly to national efforts to stabilize or reduce GHGs. We examine carbon farms in the context of corn and soybean production agriculture. We illustrate, using Iowa data but with relevance across United States corn and soybean production, the potential for carbon farms to reduce human GHG emissions and sequester carbon permanently at a rate that has meaningful impact on global greenhouse gas concentration. Carbon has been viewed as a next generation cash crop in Iowa for over a decade. The carbon farm perspective, however, goes beyond carbon as cash crop to make carbon the center of an entire farm enterprise. The transformation is possible through slight adjustment crop practices mixed with advances in technology to sequester carbon through biochar. We examine carbon balance of Iowa agriculture given only the combination of slight reduction in fertilizer and sequestration by biochar. We find the following. Iowa carbon farms could turn Iowa agriculture into a carbon sink. The estimated range of GHG reduction by statewide implementation of carbon farms is 19.46 to 90.27 MMt CO2-equivalent (CO2-e), while the current agricultural CO2-e emission estimate is 35.38 MMt CO2-e. Iowa carbon farm GHG reduction would exceed Iowa GHG reduction by wind energy (8.7 MMt CO2-e) and could exceed combined reductions from wind energy and corn grain ethanol (10.7 MMt CO2-e; 19.4 MMt CO2-e combined). In fact, Iowa carbon farms alone could exceed GHG reduction from national corn grain ethanol production (39.6 MMt CO2-e). A carbon price accessible to agricultural

  13. Infinite dilution partial molar volumes of platinum(II) 2,4-pentanedionate in supercritical carbon dioxide.

    Science.gov (United States)

    Kong, Chang Yi; Siratori, Tomoya; Funazukuri, Toshitaka; Wang, Guosheng

    2014-10-03

    The effects of temperature and density on retention of platinum(II) 2,4-pentanedionate in supercritical fluid chromatography were investigated at temperatures of 308.15-343.15K and pressure range from 8 to 40MPa by the chromatographic impulse response method with curve fitting. The retention factors were utilized to derive the infinite dilution partial molar volumes of platinum(II) 2,4-pentanedionate in supercritical carbon dioxide. The determined partial molar volumes were small and positive at high pressures but exhibited very large and negative values in the highly compressible near critical region of carbon dioxide.

  14. Supercritical Fluid Synthesis and Characterization of Catalytic Metal Nanoparticles on Carbon Nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Xiangrong; Lin, Yuehe; Wang, Chong M.; Engelhard, Mark H.; Wang, Yong; Wai, Chien M.

    2004-02-27

    A rapid, convenient and environmentally benign method has been developed for the fabrication of metal nanoparticle/multiwall carbon nanotube (MWCNT) composites. Nanoparticles of palladium, rhodium and ruthenium are deposited onto functionalized MWCNTs through a simple hydrogen reduction of metal-?-diketone precursors in supercritical carbon dioxide, and are characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analyses. These highly dispersed nanoparticles, with a narrow range of size distribution and good adhesion on MWCNT surfaces, are expected to exhibit promising catalytic properties for a variety of chemical reactions. Preliminary experiments demonstrate that Pd nanoparticles supported on MWCNTs are effective catalysts for hydrogenation of olefins in carbon dioxide. The Pd nanoparticle?MWCNT composite also shows a high electrocatalytic activity in oxygen reduction for potential fuel cell application.

  15. Utilization of supercritical carbon dioxide to produce milk protein fractions

    Science.gov (United States)

    The nutritional, functional and bioactive properties of the individual whey proteins are appreciated by health-conscious consumers, yet few methods have been developed to produce these proteins to satisfy demand. The methods that are available are relatively new technologies that have not been prove...

  16. Insights into Silicate Carbonation Processes in Water-Bearing Supercritical CO2 Fluids

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Quin RS; Thompson, Christopher J.; Loring, John S.; Windisch, Charles F.; Bowden, Mark E.; Hoyt, David W.; Hu, Jian Z.; Arey, Bruce W.; Rosso, Kevin M.; Schaef, Herbert T.

    2013-07-01

    Long-term geologic storage of carbon dioxide (CO2) is considered an integral part to moderating CO2 concentrations in the atmosphere and subsequently minimizing effects of global climate change. Although subsurface injection of CO2 is common place in certain industries, deployment at the scale required for emission reduction is unprecedented and therefore requires a high degree of predictability. Accurately modeling geochemical processes in the subsurface requires experimental derived data for mineral reactions occurring between the CO2, water, and rocks. Most work in this area has focused on aqueous-dominated systems in which dissolved CO2 reacts to form crystalline carbonate minerals. Comparatively little laboratory research has been conducted on reactions occurring between minerals in the host rock and the wet supercritical fluid phase. In this work, we studied the carbonation of wollastonite [CaSiO3] exposed to variably hydrated supercritical CO2 (scCO2) at a range of temperatures (50, 55 and 70 °C) and pressures (90,120 and 160 bar) that simulate conditions in geologic repositories. Mineral transformation reactions were followed by three novel in situ high pressure techniques, including x-ray diffraction that tracked the rate and extents of wollastonite conversion to calcite. Increased dissolved water concentrations in the supercritical CO2 resulted in increased silicate carbonation approaching ~50 wt. %. Development of thin water films on the mineral surface were directly observed with infrared spectroscopy and determined to be critical for facilitating carbonation processes. Even in extreme low water conditions, magic angle spinning nuclear magnetic resonance detected formation of Q3 [Si(OSi)3OH] and Q4 [Si(OSi)4] amorphous silica species. Unlike the thick (<10 μm) passivating silica layers observed in the fully water saturated scCO2 experiments, images obtained from a focused ion beam sectioned sample indicted these coatings were chemically wollastonite

  17. Carbon Fiber Technology Facility (CFTF)

    Data.gov (United States)

    Federal Laboratory Consortium — Functionally within the MDF, ORNL operates DOE’s unique Carbon Fiber Technology Facility (CFTF)—a 42,000 ft2 innovative technology facility and works with leading...

  18. Development of a Supercritical Carbon Dioxide Brayton Cycle: Improving VHTR Efficiency and Testing Material Compatibility - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Chang H. Oh

    2006-06-01

    Generation IV reactors will need to be intrinsically safe, having a proliferation-resistant fuel cycle and several advantages relative to existing light water reactor (LWR). They, however, must still overcome certain technical issues and the cost barrier before it can be built in the U.S. The establishment of a nuclear power cost goal of 3.3 cents/kWh is desirable in order to compete with fossil combined-cycle, gas turbine power generation. This goal requires approximately a 30 percent reduction in power cost for stateof-the-art nuclear plants. It has been demonstrated that this large cost differential can be overcome only by technology improvements that lead to a combination of better efficiency and more compatible reactor materials. The objectives of this research are (1) to develop a supercritical carbon dioxide Brayton cycle in the secondary power conversion side that can be applied to the Very-High-Temperature Gas-Cooled Reactor (VHTR), (2) to improve the plant net efficiency by using the carbon dioxide Brayton cycle, and (3) to test material compatibility at high temperatures and pressures. The reduced volumetric flow rate of carbon dioxide due to higher density compared to helium will reduce compression work, which eventually increase plant net efficiency.

  19. In situ infrared spectroscopic study of brucite carbonation in dry to water-saturated supercritical carbon dioxide.

    Science.gov (United States)

    Loring, John S; Thompson, Christopher J; Zhang, Changyong; Wang, Zheming; Schaef, Herbert T; Rosso, Kevin M

    2012-05-17

    In geologic carbon sequestration, whereas part of the injected carbon dioxide will dissolve into host brine, some will remain as neat to water saturated supercritical CO(2) (scCO(2)) near the well bore and at the caprock, especially in the short term life cycle of the sequestration site. Little is known about the reactivity of minerals with scCO(2) containing variable concentrations of water. In this study, we used high-pressure infrared spectroscopy to examine the carbonation of brucite (Mg(OH)(2)) in situ over a 24 h reaction period with scCO(2) containing water concentrations between 0% and 100% saturation, at temperatures of 35, 50, and 70 °C, and at a pressure of 100 bar. Little or no detectable carbonation was observed when brucite was reacted with neat scCO(2). Higher water concentrations and higher temperatures led to greater brucite carbonation rates and larger extents of conversion to magnesium carbonate products. The only observed carbonation product at 35 °C was nesquehonite (MgCO(3)·3H(2)O). Mixtures of nesquehonite and magnesite (MgCO(3)) were detected at 50 °C, but magnesite was more prevalent with increasing water concentration. Both an amorphous hydrated magnesium carbonate solid and magnesite were detected at 70 °C, but magnesite predominated with increasing water concentration. The identity of the magnesium carbonate products appears strongly linked to magnesium water exchange kinetics through temperature and water availability effects.

  20. Combined Extraction Processes of Lipid from Chlorella vulgaris Microalgae: Microwave Prior to Supercritical Carbon Dioxide Extraction

    Directory of Open Access Journals (Sweden)

    Farid Chemat

    2011-12-01

    Full Text Available Extraction yields and fatty acid profiles from freeze-dried Chlorella vulgaris by microwave pretreatment followed by supercritical carbon dioxide (MW-SCCO2 extraction were compared with those obtained by supercritical carbon dioxide extraction alone (SCCO2. Work performed with pressure range of 20–28 Mpa and temperature interval of 40–70 °C, gave the highest extraction yield (w/w dry weight at 28 MPa/40 °C. MW-SCCO2 allowed to obtain the highest extraction yield (4.73% compared to SCCO2 extraction alone (1.81%. Qualitative and quantitative analyses of microalgae oil showed that palmitic, oleic, linoleic and α-linolenic acid were the most abundant identified fatty acids. Oils obtained by MW-SCCO2 extraction had the highest concentrations of fatty acids compared to SCCO2 extraction without pretreatment. Native form, and microwave pretreated and untreated microalgae were observed by scanning electronic microscopy (SEM. SEM micrographs of pretreated microalgae present tearing wall agglomerates. After SCCO2, microwave pretreated microalgae presented several micro cracks; while native form microalgae wall was slightly damaged.

  1. High Pressure Vapor-Liquid Equilibrium of Supercritical Carbon Dioxide + n-Hexane System

    Institute of Scientific and Technical Information of China (English)

    YU Jinglin; TIAN Yiling; ZHU Rongjiao; LIU Zhihua

    2006-01-01

    Vapor-liquid equilibrium data of supercritical carbon dioxide + n-hexane system were measured at 313.15 K,333.15 K,353.15 K,and 373.15 K and their molar volumes and densities were measured both in the subcritical and supercritical regions ranging from 2.15 to 12.63 MPa using a variable-volume autoclave.The thermodynamic properties including mole fractions,densities,and molar volumes of the system were calculated with an equation of state by Heilig and Franck,in which a repulsion term and a square-well potential attraction term for intermolecular interaction was used.The pairwise combination rule was used to calculate the square-well molecular interaction potential and three adjustable parameters (ω,kε,kσ) were obtained.The Heilig-Franck equation of state is found to have good correlation with binary vapor-liquid equilibrium data of the carbon dioxide + n-hexane system.

  2. Experimental Study on Cooling Heat Transfer of Supercritical Carbon Dioxide Inside Horizontal Micro-Fin Tubes

    Science.gov (United States)

    Kuwahara, Ken; Higashiiu, Shinya; Ito, Daisuke; Koyama, Shigeru

    This paper deals with the experimental study on cooling heat transfer of supercritical carbon dioxide inside micro-fin tubes. The geometrical parameters in micro-fin tubes used in the present study are 6.02 mm in outer diameter, 4.76 mm to 5.11 mm in average inner diameter, 0.15 mm to 0.24 mm in fin height, 5 to 25 in helix angle, 46 to 52 in number of fins and 1.4 to 2.3 in area expansion ratio. Heat transfer coefficients were measured at 8-10 MPa in pressure, 360-690 kg/(m2•s) in mass velocity and 20-75 °C in CO2 temperature. The measured heat transfer coefficients of micro-fin tubes were 1.4 to 2 times higher than those of the smooth tube having 4.42 in inner diameter. The predicted heat transfer coefficients using the correlation equation, which was developed for single-phase turbulent fluid flow inside micro-fin-tubes, showed large deviations to the measured values. The new correlation to predict cooling heat transfer coefficient of supercritical carbon dioxide inside micro-fin tubes was developed taking into account the shape of fins based on experimental data empirically. This correlation equation agreed within ±20% of almost all of the experimental data.

  3. Combined extraction processes of lipid from Chlorella vulgaris microalgae: microwave prior to supercritical carbon dioxide extraction.

    Science.gov (United States)

    Dejoye, Céline; Vian, Maryline Abert; Lumia, Guy; Bouscarle, Christian; Charton, Frederic; Chemat, Farid

    2011-01-01

    Extraction yields and fatty acid profiles from freeze-dried Chlorella vulgaris by microwave pretreatment followed by supercritical carbon dioxide (MW-SCCO(2)) extraction were compared with those obtained by supercritical carbon dioxide extraction alone (SCCO(2)). Work performed with pressure range of 20-28 Mpa and temperature interval of 40-70 °C, gave the highest extraction yield (w/w dry weight) at 28 MPa/40 °C. MW-SCCO(2) allowed to obtain the highest extraction yield (4.73%) compared to SCCO(2) extraction alone (1.81%). Qualitative and quantitative analyses of microalgae oil showed that palmitic, oleic, linoleic and α-linolenic acid were the most abundant identified fatty acids. Oils obtained by MW-SCCO(2) extraction had the highest concentrations of fatty acids compared to SCCO(2) extraction without pretreatment. Native form, and microwave pretreated and untreated microalgae were observed by scanning electronic microscopy (SEM). SEM micrographs of pretreated microalgae present tearing wall agglomerates. After SCCO(2), microwave pretreated microalgae presented several micro cracks; while native form microalgae wall was slightly damaged.

  4. Sedative and hypnotic effects of supercritical carbon dioxide fluid extraction from Schisandra chinensis in mice

    Directory of Open Access Journals (Sweden)

    Hongyan Zhu

    2016-10-01

    Full Text Available Schisandra chinensis is a traditional Chinese medicine that has been used for treating insomnia and neurasthenia for centuries. Lignans, which are considered to be the bioactive components, are apt to be extracted by supercritical carbon dioxide. This study was conducted to investigate the sedative and hypnotic activities of the supercritical carbon dioxide fluid extraction of S. chinensis (SFES in mice and the possible mechanisms. SFES exhibited an obvious sedative effect on shortening the locomotor activity in mice in a dose-dependent (10–200 mg/kg manner. SFES (50 mg/kg, 100 mg/kg, and 200 mg/kg, intragstrically showed a strong hypnotic effect in synergy with pentobarbital in mouse sleep, and reversal of insomnia induced by caffeine, p-chlorophenylalanine and flumazenil by decreasing sleep latency, sleep recovery, and increasing sleeping time. In addition, it produced a synergistic effect with 5-hydroxytryptophan (2.5 mg/kg, intraperitoneally. The behavioral pharmacological results suggest that SFES has significant sedative and hypnotic activities, and the mechanisms might be relevant to the serotonergic and γ-aminobutyric acid (GABAergic system.

  5. Water/oil repellent property of polyester fabrics after supercritical carbon dioxide finishing

    Directory of Open Access Journals (Sweden)

    Xu Yan-Yan

    2015-01-01

    Full Text Available The strong permeability and driving force of supercritical carbon dioxide renders it an ideal medium for fabrics finishing. This paper is to use supercritical carbon dioxide medium with a solution of organic fluorine to fabricate water/oil repellent polyester fabrics. A series of characterization methods including Fourier transform infrared spectrometry, energy dispersive spectrometry, and scanning electron microscopy were carried out to evaluate the fabrics finishing. Fourier transform infrared spectrometry showed that the transmittance peak appeared at 1202.4 and 1147.4 cm-1, indicating the presence of -CF2- group on the surface of polyester fabrics. The results of energy dispersive spectrometer and scanning electron microscopy showed that the fluorine was evenly distributed on the fibers surface. In addition, a series of physical properties were detected, including contact angel, air permeability, breaking strength, and wearing resistance. The average water and hexadecane contact angles were 147.58° and 143.78°, respectively. Compared with the initial fabrics, the treated one has little change in air permeability, while its strength increased greatly. The treated fabrics gained good water/oil repellent properties while keeping good air permeability and improving mechanical property.

  6. Heterogeneous polymerizations in supercritical carbon dioxide continuous phases

    Energy Technology Data Exchange (ETDEWEB)

    DeSimone, J.M.; Maury, E.E.; Combes, J.R.; Menceloglu, Y.Z. [Univ. of North Carolina, Chapel Hill, NC (United States)

    1993-12-31

    Heterogeneous emulsion polymerizations are important industrial methods for the synthesis of various polymeric materials. These processes generally use water as the dispersing medium. The authors propose to utilize carbon dioxide as the dispersing medium which would make the polymer recovery easier and would circumvent the contamination of water. In CO{sub 2} - based emulsion process one can have either a hydrophilic dispersed phase (hydrophilic monomer) or a hydrophobic dispersed phase (hydrophobic monomer). The surfactant has to be designed to partition itself at the CO{sub 2} - monomer/polymer interface and the initiator has to be soluble in the dispersing medium. The design of the initiator and graft copolymer surfactants will be presented. One example of a graft copolymer is a copolymer of poly(ethylene oxide) macromonomer synthesized by living anionic polymerization and a fluoroacrylate monomer resulting in a graft copolymer having hydrophilic grafts and a {open_quotes}CO{sub 2}-philic{close_quotes} backbone (due to the fluorine chains). The phase behavior of these surfactants will be discussed at the meeting.

  7. In Situ Molecular Spectroscopic Evidence for CO2 Intercalation into Montmorillonite in Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Loring, John S.; Schaef, Herbert T.; Turcu, Romulus VF; Thompson, Christopher J.; Miller, Quin RS; Martin, Paul F.; Hu, Jian Z.; Hoyt, David W.; Qafoku, Odeta; Ilton, Eugene S.; Felmy, Andrew R.; Rosso, Kevin M.

    2012-04-25

    The interaction of anhydrous supercritical CO2 (scCO2) with both kaolinite and ~1W (i.e. close to but less than one layer of hydration) calcium-saturated montmorillonite was investigated under conditions relevant to geologic carbon sequestration (50 °C and 90 bar). The CO2 molecular environment was probed in situ using a combination of three novel high-pressure techniques: X-ray diffraction, magic angle spinning nuclear magnetic resonance spectroscopy and attenuated total reflection infrared spectroscopy. We report the first direct evidence that the expansion of montmorillonite under scCO2 conditions is due to CO2 migration into the interlayer. Intercalated CO2 molecules are rotationally constrained and do not appear to react with waters to form bicarbonate or carbonic acid. In contrast, CO2 does not intercalate into kaolinite. The findings show that predicting the seal integrity of caprock will have complex dependence on clay mineralogy and hydration state.

  8. In situ molecular spectroscopic evidence for CO2 intercalation into montmorillonite in supercritical carbon dioxide.

    Science.gov (United States)

    Loring, John S; Schaef, Herbert T; Turcu, Romulus V F; Thompson, Christopher J; Miller, Quin R S; Martin, Paul F; Hu, Jianzhi; Hoyt, David W; Qafoku, Odeta; Ilton, Eugene S; Felmy, Andrew R; Rosso, Kevin M

    2012-05-08

    The interaction of anhydrous supercritical CO(2) (scCO(2)) with both kaolinite and ~1W (i.e., close to but less than one layer of hydration) calcium-saturated montmorillonite was investigated under conditions relevant to geologic carbon sequestration (50 °C and 90 bar). The CO(2) molecular environment was probed in situ using a combination of three novel high-pressure techniques: X-ray diffraction, magic angle spinning nuclear magnetic resonance spectroscopy, and attenuated total reflection infrared spectroscopy. We report the first direct evidence that the expansion of montmorillonite under scCO(2) conditions is due to CO(2) migration into the interlayer. Intercalated CO(2) molecules are rotationally constrained and do not appear to react with waters to form bicarbonate or carbonic acid. In contrast, CO(2) does not intercalate into kaolinite. The findings show that predicting the seal integrity of caprock will have complex dependence on clay mineralogy and hydration state.

  9. Synthesis of soybean oil-based polymeric surfactants in supercritical carbon dioxide and investigation of their surface properties

    Science.gov (United States)

    This paper reports the preparation of polymeric surfactants (HPSO) via a two-step synthetic procedure: polymerization of soybean oil (PSO) in supercritical carbon dioxide and followed by hydrolysis of PSO with a base. HPSO was characterized and identified by using a combination of FTIR, 1H NMR, 13C...

  10. HYDROGENATION OF POLYCYCLIC AROMATIC COMPOUNDS USING NI SUPPORT ON H-BETA ZEOLITE IN SUPERCRITICAL CARBON DIOXIDE

    Science.gov (United States)

    The primary rationale for use of supercritical carbon dioxide as a solvent in hydrogenation is the elimination of mass transfer limitations, through enhancement of the solubility of hydrogen at the reaction locus. Hydrogenation of anthracene was performed using NiHB-zeolite catal...

  11. Influence of pre-treatment on enzymatic degumming of apocynum venetum bast fibers in supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    Gao Shi-Hui

    2015-01-01

    Full Text Available Pre-treatment of apocynum venetum bast fibers in supercritical carbon dioxide can improve the efficiency of enzymatic degumming of apocynum venetum bast fiber. This paper studies experimentally effect of pressure and degumming time on degradation rate, the results can be used for optimal design of degumming.

  12. Precipitation polymerization of hydrophobically modified polyelectrolyte poly(AA-co-ODA) in supercritical carbon dioxide and solution rheology properties

    Science.gov (United States)

    Zhang, Huaiping; Li, Wei; Cao, Qing; Chen, Mingcai

    2014-05-01

    Hydrophobically modified (HM) polyelectrolytes were prepared by using precipitation polymerization of acrylic acid (AA) and octadecyl acrylate (ODA) in various molar ratios in supercritical carbon dioxide. The product was obtained in the form of a white powder and the micrographs show aggregates of primary particles properties.

  13. PALM KERNEL OIL SOLUBITY EXAMINATION AND ITS MODELING IN EXTRACTION PROCESS USING SUPERCRITICAL CARBON DIOXIDE

    Directory of Open Access Journals (Sweden)

    Wahyu Bahari Setianto

    2013-11-01

    Full Text Available Application of  supercritical carbon dioxide (SC-CO2 to vegetable oil extraction became an attractive technique due to its high solubility, short extraction time and simple purification. The method is considered as earth friendly technology due to the absence of chemical usage. Solubility of solute-SC-CO2 is an important data for application of the SC-CO2 extraction. In this work, the equilibrium solubility of the palm kernel oil (PKO in SC-CO2 has been examined using extraction curve analysis. The examinations were performed at temperature and pressure ranges of  323.15 K to 353.15 K and 20.7 to 34.5 MPa respectively. It was obtained that the experimental solubility were from 0.0160 to 0.0503 g oil/g CO2 depend on the extraction condition. The experimental solubility data was well correlated with a solvent density based model with absolute percent deviation of 0.96. PENENTUAN KELARUTAN MINYAK INTI KELAPA SAWIT DAN PEMODELAN EKSTRAKSI DENGAN KARBON DIOKSIDA SUPERKRITIK. Sehubungan dengan kelarutan yang tinggi, waktu ekstraksi yang pendek dan pemurnian hasil yang mudah, aplikasi karbon dioksida superkritis (SC-CO2 pada ekstraksi minyak nabati menjadi sebuah teknik ekstraksi yang menarik. Karena tanpa penggunaan bahan kimia, metode ekstraksi ini dianggap sebagai teknologi yang ramah lingkungan. Kelarutan zat terlarut pada SC-CO2 merupakan data yang penting dalam aplikasi SC-CO2 pada proses ekstraksi.  Pada penelitian ini,  kelarutan kesetimbangan dari minyak biji sawit (PKO dalam SC-CO2 telah diuji dengan mengunakan analisa kurva proses ekstraksi. Pengujian kelarutan tersebut dilakukan pada rentang suhu 323,15 K sampai 353,15 K dan rentang tekanan 20,7 MPa sampai 34,5 MPa. Hasil analisa menunjukkan bahwa kelarutan kesetimbangan hasil percobaan  PKO pada SC-CO2 adalah 0.0160 g minyak/g CO2 sampai 0,0503 g minyak/g CO2 tergantung pada kondisi ekstraksi. Data kelarutan kesetimbangan hasil percobaan  telah dikorelasaikan dengan baik menggunakan

  14. Measurement and correlation study of silymarin solubility in supercritical carbon dioxide with and without a cosolvent using semi-empirical models and back-propagation artificial neural networks

    Directory of Open Access Journals (Sweden)

    Gang Yang

    2017-09-01

    Full Text Available The solubility data of compounds in supercritical fluids and the correlation between the experimental solubility data and predicted solubility data are crucial to the development of supercritical technologies. In the present work, the solubility data of silymarin (SM in both pure supercritical carbon dioxide (SCCO2 and SCCO2 with added cosolvent was measured at temperatures ranging from 308 to 338 K and pressures from 8 to 22 MPa. The experimental data were fit with three semi-empirical density-based models (Chrastil, Bartle and Mendez-Santiago and Teja models and a back-propagation artificial neural networks (BPANN model. Interaction parameters for the models were obtained and the percentage of average absolute relative deviation (AARD% in each calculation was determined. The correlation results were in good agreement with the experimental data. A comparison among the four models revealed that the experimental solubility data were more fit with the BPANN model with AARDs ranging from 1.14% to 2.15% for silymarin in pure SCCO2 and with added cosolvent. The results provide fundamental data for designing the extraction of SM or the preparation of its particle using SCCO2 techniques.

  15. Preparation of microcellular composites with biomimetic structure via supercritical fluid technology

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A new microcellular composite material with a biomimetic structure has been prepared via the supercritical fluid (SCF) technology. The resultant material has a clear biomimetic structure like bamboo and wood. The skin region is enriched with oriented high-strength thermotropic liquid crystal polymer fibrils, while the core region with polystyrene (PS) micro-cells. The diameter and density of micro- cells can be controlled by the processing parameters such as temperature and pressure. And the skin thickness can be controlled conveniently by varying the composition of polystyrene and liquid crystal polymer.

  16. [The extraction technology of epigoitri from isatidis radix by supercritical CO2 fluid].

    Science.gov (United States)

    Nian, Si-Hui; Liu, Chun-Yun; Liu, Li-Min; Yang, Li-Fen

    2013-07-01

    To study the extraction technology of epigoitri from Isatidis Radix by supercritical CO2 fluid. The effects of pressure, temperature, time, concentration and dosage of alcohol were studied by single factor analysis and orthogonal test. The optimized conditions were as follows: The pressure was 20 MPs, the temperature was 50 degrees C, the time was 2 h, concentration of alcohol was 100%, dosage was 80 mL. The content of epigoitri in the extract could reach 38.63% under the above conditions. This method is simple, rapid and it is suitable for the extraction of epigoitri from Isatidis Radix.

  17. Removal of residual chlorine from Indiana 5 coal by supercritical carbon dioxide extraction

    Energy Technology Data Exchange (ETDEWEB)

    Kocher, B.S.; Azzam, F.O.; Lee, S. (University of Akron, Akron, OH (United States). Dept. of Chemical Engineering)

    1994-01-01

    The perchloroethylene coal desulfurization process has unique advantages as a precombustion coal cleaning process, that include high cleaning efficiencies, mild process conditions, minimal output of undesirable byproducts, and cost effectiveness. However, the use of perchloroethylene in the process renders an important process engineering problem of complete recovery and reuse of perchloroethylene, thus requiring a 'zero discharge' condition of the solvent. Therefore, the treated coal must be stripped of any residual perchloroethylene. Carbon dioxide (CO[sub 2]) in its supercritical state has been investigated for its ability to remove chlorine from Indiana 5 coal, that has been desulfurized by the perchloroethylene (PCE) process. The reduction of Cl content from a PCE treated and filtered coal has been as high as 78% by mass. The experiments have been carried out following a statistical experimental design and the discerning characteristics of the process have been identified. The solvent density and extraction conditions can be tailored in such a way as to optimally remove C from the coal without any detrimental effects on the coal matrix. The supercritical CO[sub 2] extraction process can be successfully implemented to the PCE coal cleaning process by replacing energy intensive steps of steam stripping and vacuum drying. 6 refs., 3 figs., 3 tabs.

  18. Dynamic modelling and simulation of CSP plant based on supercritical carbon dioxide closed Brayton cycle

    Science.gov (United States)

    Hakkarainen, Elina; Sihvonen, Teemu; Lappalainen, Jari

    2017-06-01

    Supercritical carbon dioxide (sCO2) has recently gained a lot of interest as a working fluid in different power generation applications. For concentrated solar power (CSP) applications, sCO2 provides especially interesting option if it could be used both as the heat transfer fluid (HTF) in the solar field and as the working fluid in the power conversion unit. This work presents development of a dynamic model of CSP plant concept, in which sCO2 is used for extracting the solar heat in Linear Fresnel collector field, and directly applied as the working fluid in the recuperative Brayton cycle; these both in a single flow loop. We consider the dynamic model is capable to predict the system behavior in typical operational transients in a physically plausible way. The novel concept was tested through simulation cases under different weather conditions. The results suggest that the concept can be successfully controlled and operated in the supercritical region to generate electric power during the daytime, and perform start-up and shut down procedures in order to stay overnight in sub-critical conditions. Besides the normal daily operation, the control system was demonstrated to manage disturbances due to sudden irradiance changes.

  19. Process improvements for the supercritical in situ transesterification of carbonized algal biomass.

    Science.gov (United States)

    Levine, Robert B; Bollas, Alexandra; Savage, Phillip E

    2013-05-01

    This work focuses on the production of biodiesel from wet, lipid-rich algal biomass using a two-step process involving hydrothermal carbonization (HTC) and supercritical in situ transesterification (SC-IST). Algal hydrochars produced by HTC were reacted in supercritical ethanol to determine the effects of reaction temperature, time, ethanol loading, water content, and pressure on the yield of fatty acid ethyl esters (FAEE). Reaction temperatures above 275 °C resulted in substantial thermal decomposition of unsaturated FAEE, thereby reducing yields. At 275 °C, time and ethanol loading had a positive impact on FAEE yield while increasing reaction water content and pressure reduced yields. FAEE yields as high as 79% with a 5:1 ethanol:fatty acid (EtOH:FA) molar ratio (150 min) and 89% with a 20:1 EtOH:FA molar ratio (180 min) were achieved. This work demonstrates that nearly all lipids within algal hydrochars can be converted into biodiesel through SC-IST with only a small excess of alcohol.

  20. Synthesis and crystallization of titanium dioxide in supercritical carbon dioxide (scCO2)

    Science.gov (United States)

    Kaleva, A.; Heinonen, S.; Nikkanen, J.-P.; Levänen, E.

    2017-02-01

    In this work, a simple and low-temperature method to synthesize titanium dioxide (TiO2) particles with supercritical carbon dioxide is presented. The particles were synthesized by measuring 5 ml of tetra-n-butyl orthotitanate precursor to the supercritical chamber. The pressure was maintained at 15.0 MPafor all experiments. Reaction temperatures used were 50 °C or 70 °C. After reaching treatment parameters 10 ml of deionized water was introduced to the chamber with a co-solvent pump. A mixer was used inside the chamber to ensure proper mixing of water and precursor. Reaction times of 10, 60 and 300 min were used. Characterization of the particle crystal phase was determined by X-ray diffraction, differential scanning calorimetry and transmission electron microscopy. The specific surface areas were measured with nitrogen adsorption tests (BET). The results showed that the particles synthesized with reaction times of 10 and 60 min contained brookite as the crystalline phase. With longer reaction time of 300 min the phase shifted to anatase. In most experiments there was also significant amount of amorphous phase present. The specific surface areas varied between 274.3–566.6 m2/g.

  1. Investigation on adsorption and regeneration performances of multi-walled carbon nanotubes by supercritical water technique

    Institute of Scientific and Technical Information of China (English)

    HE Jin-mei; HUANG Yu-dong; MENG Ling-hui; ZHAO Jin-hua; SUN De-zhi

    2009-01-01

    In this paper,adsorption and regeneration characteristics of multi-walled carbon nanotubes (MWNTs)used as adsorbent were investigated for the removal of l,3-benzenediol(BDO)from water by the supercritical water(SCW)technique.FTIR,XPS,SEM and dispersion stability tests were used to characterize the structure and surface morphology of CNTs.The results showed that CNTs surfaces were slishfly activated and strongly etched in supercritical water system.The adsorption capacity of SCW-treated CNTs was hisher than that of raw CNTs.The adsorbed amounts for treated CNTs and raw CNTs samples at the same initial concentra-tion of 60 mg/L were ca.16.42 and 7.30 mg/g,respectively.The BDO adsorption of treated CNTs Was due to the physical adsorption.The experimental data fit Freundlich isotherm model better than Langmuir one.The loaded adsorbent could be efficiently desorbed and regenerated by SCW technique.Therefore,SCW is a promis-ing and environmentally friendly technique for the improvement of adsorption and regeneration of CNTs.

  2. Safety Control on the Chocking Process of Supercritical Carbon Dioxide Pipeline

    Directory of Open Access Journals (Sweden)

    Qing Zhao

    2014-09-01

    Full Text Available Transportation safety of supercritical CO2 pipeline is a key aspect of carbon capture and storage (CCS. For reducing the high pressure in supercritical pipeline when accidental cases arise, man-made release will be applied using chocking process. The downstream parameters of chocking process can be predicted based on the adiabatic process assumption. In the critical chocking process, the critical velocity at outlet is sonic. A chocking pipe can be designed for buffering between different chocking orifices according to the length of turbulence area produced by jetting momentum. For the effect of noise hazard produced by large jetting velocity, a muffler can be applied at the outlet of final stage orifice to atmosphere. For the influence of impurities on the chocking process of anthropogenic CO2 pipeline, the presence of SO2 as an impurity is helpful for increasing the downstream temperatures through the chocking device to prevent the frozen hazard, whereas the presence of N2 as an impurity indicates a lower downstream temperature. The higher initial temperature can prevent the dry ice formation at the outlet of vent pipe when the multistage chocking is applied.

  3. Optimization of the Supercritical Carbon Dioxide Separation of Bergapten from Bergamot Essential Oil.

    Science.gov (United States)

    Sicari, Vincenzo

    2017-07-31

    The possibility of following traditional cold-press extraction with the post process continuous separation ofbergapten from bergamot essential oil was investigated. A fractionation tower was used in an experiment in which cold-pressed bergamot oil was extracted in a continuous countercurrent process by supercritical carbon dioxide under different conditions. Bergapten is fairly soluble in CO₂ in its supercritical phase, in particular at a density of 277.90 kg⋅m(–3), corresponding to a pressure of 8 MPa and temperature of 40°C. Under these conditions, an extract with 0.198% bergapten was obtained, a figure slightly below the percentage of bergapten contained in cold-pressed oil (0.21%). However, at densities below 200 kg⋅m(–3), the amount of bergapten in the extracted oil was negligible. Of all tested conditions for separation, the best was found to be at a pressure of 8 MPa and temperature of 70°C, conditions under which bergapten was not detected. The results of the experiment showed that bergapten, and the non-volatile fraction in general, was extracted only in small quantities and was not extracted at all with at a CO₂ pressure of 8 MPa.

  4. Protolytic carbon film technology

    Energy Technology Data Exchange (ETDEWEB)

    Renschler, C.L.; White, C.A.

    1996-04-01

    This paper presents a technique for the deposition of polyacrylonitrile (PAN) on virtually any surface allowing carbon film formation with only the caveat that the substrate must withstand carbonization temperatures of at least 600 degrees centigrade. The influence of processing conditions upon the structure and properties of the carbonized film is discussed. Electrical conductivity, microstructure, and morphology control are also described.

  5. In Situ Infrared Spectroscopic Study of Forsterite Carbonation in Wet Supercritical CO2

    Energy Technology Data Exchange (ETDEWEB)

    Loring, John S.; Thompson, Christopher J.; Wang, Zheming; Joly, Alan G.; Sklarew, Deborah S.; Schaef, Herbert T.; Ilton, Eugene S.; Rosso, Kevin M.; Felmy, Andrew R.

    2011-07-19

    Carbonation reactions are central to the prospect of CO2 trapping by mineralization in geologic reservoirs. In contrast to the relevant aqueous-mediated reactions, little is known about the propensity for carbonation in the long-term partner fluid: water-containing supercritical carbon dioxide (‘wet’ scCO2). We employed in situ mid-infrared spectroscopy to follow the reaction of a model silicate mineral (forsterite, Mg2SiO4) for 24 hr with wet scCO2 at 50°C and 180 atm, using water concentrations corresponding to 0%, 55%, 95%, and 136% saturation. Results show a dramatic dependence of reactivity on water concentration and the presence of liquid water on the forsterite particles. Exposure to neat scCO2 showed no detectable carbonation reaction. At 55% and 95% water saturation, a liquid-like thin water film was detected on the forsterite particles; less than 1% of the forsterite transformed, mostly within the first 3 hours of exposure to the fluid. At 136% saturation, where an (excess) liquid water film approximately several nanometers thick was intentionally condensed on the forsterite, the carbonation reaction proceeded continuously for 24 hr with 10% to 15% transformation. Our collective results suggest constitutive links between water concentration, water film formation, reaction rate and extent, and reaction products in wet scCO2.

  6. Direct synthesis of dimethyl carbonate and propylene glycol using potassium bicarbonate as catalyst in supercritical CO2

    OpenAIRE

    Wen Yicun; Zhang Rui; Cang Yu; Zhang Jianchao; Liu Lixiao; Guo Xuhong; Fan Bin

    2015-01-01

    The improved one-pot synthesis of dimethyl carbonate and propylene glycol from propylene oxide, supercritical carbon dioxide, and methanol with potassium bicarbonate as the catalyst has been reported in this paper. As far as we know, it is the first time to use potassium bicarbonate only as the catalyst in the production process which is simple and cheap. Satisfactory conversion rate of propylene oxide and yield of the products could be achieved at the optimized conditions with quite a small ...

  7. Fiscal 1995 research investigation on chemical process technology using supercritical fluid; 1995 nendo chorinkai ryutai wo riyoshita kagaku process gijutsu ni kansuru chosa kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    With relation to the supercritical fluid utilization technology, conducted in fiscal 1995 were collection of basic data, extraction of R and D subjects and survey/analysis of application fields based on the literature survey and overseas field survey. From the research results, the following were selected as research subjects: as to the clean/recycling process technology, non-selection cascade treatment process of mixed waste plastics, hazardous waste treatment process, and radioactive waste treatment process. As to the unused resource utilization process technology, the supercritical submerged combustion power generation process, heavy hydrocarbon resource reutilization process, biomass synthetic utilization process, and carbon dioxide reutilization process. As to the next generation reaction process technology, the simple reaction process, de-organic solvent process, chemical materialization process for methane, and reaction separation combined process. As the innovative material process technology, the plastic forming process, high-functional materials, high-efficiency energy conversion materials, and heightening of function of solid wastes. 537 refs., 116 figs., 54 tabs.

  8. Extraction of curcumin from Curcuma longa L. using ultrasound assisted supercritical carbon dioxide

    Science.gov (United States)

    Kimthet, Chhouk; Wahyudiono, Kanda, Hideki; Goto, Motonobu

    2017-05-01

    Curcumin is one of phenolic compounds, which has been recently shown to have useful pharmacological properties such as anti-inflammatory, anti-bacterial, anti-carcinogenic, antifungal, and antimicrobial activities. The objective of this research is to extract the curcumin from Curcuma longa L. using ultrasound assisted supercritical carbon dioxide extraction (USC-CO2). The extraction was performed at 50°C, 25 MPa, CO2 flow rate of 3 mL/min with 10% cosolvent. The result of extraction, thermogravimetry (TG), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) showed that ultrasound power could disrupt cell wall and release the target compounds from Curcuma longa L. USC-CO2 could provide higher curcumin content in the extracts and faster extraction compared to SC-CO2 extraction without ultrasound.

  9. Dynamical analysis of high-pressure supercritical carbon dioxide jet in well drilling

    Institute of Scientific and Technical Information of China (English)

    DU Yu-kun; WANG Rui-he; NI Hong-jian; HUANG Zhi-yuan; LI Mu-kun

    2013-01-01

    This paper presents the design of an experimental setup and mathematical and physical models to determine the dynamical characteristics of the high-pressure supercritical carbon dioxide (SC-CO2) jet with a highly potential applications in the well drilling.The effects of three major factors on the wellbore dynamical characteristics of the high-pressure SC-CO2 jet,i.e.,the nozzle diameter,the standoff distance and the jet pressure are determined.It is indicated that the pressure of CO2 reduces severely in the SC-CO2 jet impact process.It is also found that the bottom-hole pressure and the temperature increase as the nozzle diameter increases but decrease with the increase of the standoff distance.The higher the jet pressure at the wellbore inlet is,the higher the pressure and the lower the temperature at the bottom-hole will be.

  10. Supercritical extraction of pupunha (Guilielma speciosa oil in a fixed bed using carbon dioxide

    Directory of Open Access Journals (Sweden)

    Araújo M.E.

    2000-01-01

    Full Text Available The pupunha (Guilielma speciosa is the fruit of a palm tree typical of the Brazilian Northern region, whose stem is used as a source of heart of palm. The fruit, which is about 65% pulp, is a source of oil and carotenes. In the present work, an analysis of the kinetics of supercritical extraction of oil from the pupunha pulp is presented. Carbon dioxide was used as solvent. The extractions were carried out at 25 MPa and 323 K and 30 MPa and 318 K. The chemical composition of the extracts in terms of fatty acids was determined by gas chromatography. The amount of oleic acid, a saturated fatty acid, in the CO2 extracts was larger than that in the extract obtained with hexane. The overall extraction curves were modeled using the single-parameter model proposed in the literature to describe the desorption of toluene from activated coal.

  11. Separation of cashew (Anacardium occidentale L.) nut shell liquid with supercritical carbon dioxide.

    Science.gov (United States)

    Smith, R L; Malaluan, R M; Setianto, W B; Inomata, H; Arai, K

    2003-05-01

    Cashew nut shell liquid (CNSL) represents the largest readily available bioresource of alkenyl phenolic compounds. In this work, separation of CNSL from the pericarp of the cashew nut with supercritical carbon dioxide was studied. In the initial extractions with CO(2) at 40-60 degrees C and at pressures from 14.7 to 29.4 MPa, low yields were obtained. However, when the extractions were performed with one or more intermediate depressurization steps, the yield of CNSL increased to as high as 94%. Most of the oil did not separate from the shell during the depressurization step, but was obtained during the subsequent repressurization. The CNSL extract had a clear light brownish pink color and exhibited no evidence of polymerization or degradation. The pressure profile extraction method proposed in this work increases the possible CNSL extraction yields and greatly reduces the amount of CO(2) required for CNSL separation.

  12. Extraction of cashew (Anacardium occidentale) nut shell liquid using supercritical carbon dioxide.

    Science.gov (United States)

    Patel, Rajesh N; Bandyopadhyay, Santanu; Ganesh, Anuradda

    2006-04-01

    This work investigated the extraction of cashew nut shell liquid (CNSL) using supercritical carbon dioxide (SC-CO(2)). Effects of process parameters such as extraction pressure, temperature and flow rate of SC-CO(2) were investigated. The yield of CNSL increased with increase in pressure, temperature and mass flow rate of SC-CO(2). However, under different operating conditions, the composition of CNSL varied. The study of physical properties and chemical composition of the oil obtained through super critical fluid extraction (SCFE) showed better quality as compared to the CNSL obtained through thermal route. Experimental results were compared with diffusion based mass transfer model. Based on this simple model, extraction time was optimized.

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

    Science.gov (United States)

    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.

  14. Radiation effects on the foaming of atactic polypropylene with supercritical carbon dioxide

    Science.gov (United States)

    Yang, Chenguang; Zhe, Xing; Zhang, Mingxing; Wang, Mouhua; Wu, Guozhong

    2017-02-01

    Atactic polypropylene (PP) samples with melt flow indices (MFI) of 7.0 g/10 min were irradiated and then foamed with supercritical carbon dioxide (scCO2). A detailed investigation was carried out to understand the effect of radiation on the scCO2 foaming of polypropylene. Variations in the molecular weight, branching degree, crystallinity, and melting and crystallization temperatures of irradiated PP were investigated. The cell diameter, cell density, volume expansion ratio and foaming rate were analyzed in detail under different conditions. It was found that the cell structure of PP foam became more uniform and the foaming temperature window increased to 10 °C. This compares favorably to the 4 °C observed with pristine atactic PP. The best cell morphology was observed at a dose of 30 kGy. The corresponding average diameter and cell density were 16.4 μ m and 5.7×107 cells/cm3, respectively.

  15. Dissolution-Induced Nanowire Synthesis on Hot-Dip Galvanized Surface in Supercritical Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Aaretti Kaleva

    2017-07-01

    Full Text Available In this study, we demonstrate a rapid treatment method for producing a needle-like nanowire structure on a hot-dip galvanized sheet at a temperature of 50 °C. The processing method involved only supercritical carbon dioxide and water to induce a reaction on the zinc surface, which resulted in growth of zinc hydroxycarbonate nanowires into flower-like shapes. This artificial patina nanostructure predicts high surface area and offers interesting opportunities for its use in industrial high-end applications. The nanowires can significantly improve paint adhesion and promote electrochemical stability for organic coatings, or be converted to ZnO nanostructures by calcining to be used in various semiconductor applications.

  16. Improved adhesion performances of aramid fibers with vinyl epoxy via supercritical carbon dioxide modification

    Science.gov (United States)

    Qin, M. L.; Kong, H. J.; Yu, M. H.; Teng, C. Q.

    2017-06-01

    In this paper, aramid fibers were treated under supercritical carbon dioxide (SCCO2) with isocyanate terminated liquid nitrile rubber to improve the adhesion performances of vinyl epoxy composites. The interfacial shear strength (IFSS) of vinyl epoxy composites was investigated by micro-bond test. The results indicate that the surface modification of aramid fibers in SCCO2 was an efficient method to increase the adhesion performances between fibers and vinyl epoxy. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) were adopted to investigate the surface structure and composition of aramid fibers. The flexural strength and interlaminar shear strength (ILSS) of treated aramid fibers/vinyl epoxy composites was improved by 18.1% and 28.9% compared with untreated aramid fibers, respectively. Furthermore, the fractured surfaces of the composites were observed by SEM, which showed that the interfacial adhesion of composites has been remarkably changed.

  17. Binary Diffusion Coefficients of Platinum(II) Acetylacetonate in Supercritical Carbon Dioxide.

    Science.gov (United States)

    Kong, Chang Yi; Siratori, Tomoya; Wang, Guosheng; Sako, Takeshi; Funazukuri, Toshitaka

    2013-11-14

    Binary diffusion coefficients (D12) and retention factors (k) of platinum(II) acetylacetonate at infinitesimal concentration in supercritical (sc) carbon dioxide (CO2) were measured by the chromatographic impulse response method with a poly(ethylene glycol) coated capillary column at temperatures from (308.15 to 343.15) K and pressures from (8.5 to 40.0) MPa, and D12 in liquid ethanol at temperatures from (298.15 to 333.15) K and atmospheric pressure by the Taylor dispersion method. As has been seen for our previously reported data on other metal complexes measured in sc CO2 and organic solvents, the D12 data in sc CO2 and liquid ethanol were represented by a function of temperature and solvent viscosity. The D12 values for metal complexes were not related to the solute molecular weights. The k values in sc CO2 were expressed by a function of temperature and CO2 density.

  18. Mechanical behaviour of cyclic olefin copolymer/exfoliated graphite nanoplatelets nanocomposites foamed through supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    A. Biani

    2016-12-01

    Full Text Available A cycloolefin copolymer matrix was melt mixed with exfoliated graphite nanoplatelets (xGnP and the resulting nanocomposites were foamed by supercritical carbon dioxide. The density of the obtained foams decreased with the foaming pressure. Moreover, xGnP limited the cell growth during the expansion process thus reducing the cell diameter (from 1.08 to 0.22 mm with an XGnP amount of 10 wt% at 150 bar and increasing the cell density (from 12 to 45 cells/mm2 with a nanofiller content of 10 wt% at 150 bar. Electron microscopy observations of foams evidenced exfoliation and orientation of the nanoplatelets along the cell walls. Quasi-static compressive tests and tensile creep tests on foams clearly indicated that xGnP improved the modulus (up to a factor of 10 for a xGnP content of 10 wt% and the creep stability.

  19. Catalytic functionalization of methane and light alkanes in supercritical carbon dioxide.

    Science.gov (United States)

    Fuentes, M Ángeles; Olmos, Andrea; Muñoz, Bianca K; Jacob, Kane; González-Núñez, M Elena; Mello, Rossella; Asensio, Gregorio; Caballero, Ana; Etienne, Michel; Pérez, Pedro J

    2014-08-25

    The development of catalytic methods for the effective functionalization of methane yet remains a challenge. The best system known to date is the so-called Catalytica Process based on the use of platinum catalysts to convert methane into methyl bisulfate with a TOF rate of 10(-3) s. In this contribution, we report a series of silver complexes containing perfluorinated tris(indazolyl)borate ligands that catalyze the functionalization of methane into ethyl propionate upon reaction with ethyl diazoacetate (EDA) by using supercritical carbon dioxide (scCO2) as the reaction medium. The employment of this reaction medium has also allowed the functionalization of ethane, propane, butane, and isobutane.

  20. Depolymerization of Poly(bisphenol A carbonate) in Subcritical and Supercritical Toluene

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The depolymerization of poly(bisphenol A carbonate)(PC) in subcritical and supercritical toluene was studied. The experimental parameters, which influence the depolymerization reaction such as temperature (570-633 K), pressure (4.0-7.0 MPa), reaction time (5-60 min), and toluene to PC weight ratio (3.0-11.0), were investigated, and the reaction products were determined by GC, GC/MS and FT-IR spectrometer. It was found that the main product of the depolymerization reaction was bisphenol A(BPA). BPA accounted for over 55.7% of the depolymerization products at reaction temperature 613 K, pressure 5.0-6.0 MPa, reaction time 15 min and toluene/PC weight ratio of around 7.0.

  1. Dry Air Cooler Modeling for Supercritical Carbon Dioxide Brayton Cycle Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Moisseytsev, A. [Argonne National Lab. (ANL), Argonne, IL (United States); Sienicki, J. J. [Argonne National Lab. (ANL), Argonne, IL (United States); Lv, Q. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-07-28

    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 (sCO2) Brayton cycles. The modeling can now be utilized to optimize and simulate sCO2 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 sCO2 Brayton cycle is that it enables 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

  2. Life cycle analysis of geothermal power generation with supercritical carbon dioxide

    Science.gov (United States)

    Frank, Edward D.; Sullivan, John L.; Wang, Michael Q.

    2012-09-01

    Life cycle analysis methods were employed to model the greenhouse gas emissions and fossil energy consumption associated with geothermal power production when supercritical carbon dioxide (scCO2) is used instead of saline geofluids to recover heat from below ground. Since a significant amount of scCO2 is sequestered below ground in the process, a constant supply is required. We therefore combined the scCO2 geothermal power plant with an upstream coal power plant that captured a portion of its CO2 emissions, compressed it to scCO2, and transported the scCO2 by pipeline to the geothermal power plant. Emissions and energy consumption from all operations spanning coal mining and plant construction through power production were considered, including increases in coal use to meet steam demand for the carbon capture. The results indicated that the electricity produced by the geothermal plant more than balanced the increase in energy use resulting from carbon capture at the coal power plant. The effective heat rate (BTU coal per total kW h of electricity generated, coal plus geothermal) was comparable to that of traditional coal, but the ratio of life cycle emissions from the combined system to that of traditional coal was 15% when 90% carbon capture efficiency was assumed and when leakage from the surface was neglected. Contributions from surface leakage were estimated with a simple model for several hypothetical surface leakage rates.

  3. Extraction of hydrocarbons from high-maturity Marcellus Shale using supercritical carbon dioxide

    Science.gov (United States)

    Jarboe, Palma B.; Philip A. Candela,; Wenlu Zhu,; Alan J. Kaufman,

    2015-01-01

    Shale is now commonly exploited as a hydrocarbon resource. Due to the high degree of geochemical and petrophysical heterogeneity both between shale reservoirs and within a single reservoir, there is a growing need to find more efficient methods of extracting petroleum compounds (crude oil, natural gas, bitumen) from potential source rocks. In this study, supercritical carbon dioxide (CO2) was used to extract n-aliphatic hydrocarbons from ground samples of Marcellus shale. Samples were collected from vertically drilled wells in central and western Pennsylvania, USA, with total organic carbon (TOC) content ranging from 1.5 to 6.2 wt %. Extraction temperature and pressure conditions (80 °C and 21.7 MPa, respectively) were chosen to represent approximate in situ reservoir conditions at sample depth (1920−2280 m). Hydrocarbon yield was evaluated as a function of sample matrix particle size (sieve size) over the following size ranges: 1000−500 μm, 250−125 μm, and 63−25 μm. Several methods of shale characterization including Rock-Eval II pyrolysis, organic petrography, Brunauer−Emmett−Teller surface area, and X-ray diffraction analyses were also performed to better understand potential controls on extraction yields. Despite high sample thermal maturity, results show that supercritical CO2 can liberate diesel-range (n-C11 through n-C21) n-aliphatic hydrocarbons. The total quantity of extracted, resolvable n-aliphatic hydrocarbons ranges from approximately 0.3 to 12 mg of hydrocarbon per gram of TOC. Sieve size does have an effect on extraction yield, with highest recovery from the 250−125 μm size fraction. However, the significance of this effect is limited, likely due to the low size ranges of the extracted shale particles. Additional trends in hydrocarbon yield are observed among all samples, regardless of sieve size: 1) yield increases as a function of specific surface area (r2 = 0.78); and 2) both yield and surface area increase with increasing

  4. Extraction fatty acid as a source to produce biofuel in microalgae Chlorella sp. and Spirulina sp. using supercritical carbon dioxide

    Science.gov (United States)

    Tai, Do Chiem; Hai, Dam Thi Thanh; Vinh, Nguyen Hanh; Phung, Le Thi Kim

    2016-06-01

    In this research, the fatty acids of isolated microalgae were extracted by some technologies such as maceration, Soxhlet, ultrasonic-assisted extraction and supercritical fluid extraction; and analyzed for biodiesel production using GC-MS. This work deals with the extraction of microalgae oil from dry biomass by using supercritical fluid extraction method. A complete study at laboratory of the influence of some parameters on the extraction kinetics and yields and on the composition of the oil in terms of lipid classes and profiles is proposed. Two types of microalgae were studied: Chlorella sp. and Spirulina sp. For the extraction of oil from microalgae, supercritical CO2 (SC-CO2) is regarded with interest, being safer than n-hexane and offering a negligible environmental impact, a short extraction time and a high-quality final product. Whilst some experimental papers are available on the supercritical fluid extraction (SFE) of oil from microalgae, only limited information exists on the kinetics of the process. These results demonstrate that supercritical CO2 extraction is an efficient method for the complete recovery of the neutral lipid phase.

  5. Supercritical Carbon Dioxide Power Generation System Definition: Concept Definition and Capital Cost Estimate

    Energy Technology Data Exchange (ETDEWEB)

    Stoddard, Larry [Black & Veatch, Kansas City, MO (United States); Galluzzo, Geoff [Black & Veatch, Kansas City, MO (United States); Andrew, Daniel [Black & Veatch, Kansas City, MO (United States); Adams, Shannon [Black & Veatch, Kansas City, MO (United States)

    2016-06-30

    The Department of Energy’s (DOE’s) Office of Renewable Power (ORP) has been tasked to provide effective program management and strategic direction for all of the DOE’s Energy Efficiency & Renewable Energy’s (EERE’s) renewable power programs. The ORP’s efforts to accomplish this mission are aligned with national energy policies, DOE strategic planning, EERE’s strategic planning, Congressional appropriation, and stakeholder advice. ORP is supported by three renewable energy offices, of which one is the Solar Energy Technology Office (SETO) whose SunShot Initiative has a mission to accelerate research, development and large scale deployment of solar technologies in the United States. SETO has a goal of reducing the cost of Concentrating Solar Power (CSP) by 75 percent of 2010 costs by 2020 to reach parity with base-load energy rates, and 30 percent further reductions by 2030. The SunShot Initiative is promoting the implementation of high temperature CSP with thermal energy storage allowing generation during high demand hours. The SunShot Initiative has funded significant research and development work on component testing, with attention to high temperature molten salts, heliostats, receiver designs, and high efficiency high temperature supercritical CO2 (sCO2) cycles. DOE retained Black & Veatch to support SETO’s SunShot Initiative for CSP solar power tower technology in the following areas: 1. Concept definition, including costs and schedule, of a flexible test facility to be used to test and prove components in part to support financing. 2. Concept definition, including costs and schedule, of an integrated high temperature molten salt (MS) facility with thermal energy storage and with a supercritical CO2 cycle generating approximately 10MWe. 3. Concept definition, including costs and schedule, of an integrated high temperature falling particle facility with thermal energy storage and with a supercritical CO2 cycle

  6. 超临界流体技术制各类胡萝卜素纳米颗粒%Carotenoids particle formation by supercritical fluid technologies

    Institute of Scientific and Technical Information of China (English)

    全灿; Johan Carlfors; Charlotta Turner

    2009-01-01

    Based on the solubility in supercritical CO2, two strategies in which CO2 plays different roles are used to make quercetine and astaxanthin particles by supercritical fluid technologies. The experimental results showed that micronized quercetine particles with mean particle size of 1.0-1.5 um can be made via solution enhanced dis-persion by supercritical fluids (SEDS) process, in which CO2 worked as turbulent anti-solvent; while for astaxan-thin, micronized particles with mean particle size of 0.3-0.8 um were also made successfully by rapid expansion supercritical solution (RESS) process.

  7. The Role of H2O in the Carbonation of Forsterite in Supercritical CO2

    Energy Technology Data Exchange (ETDEWEB)

    Kwak, Ja Hun; Hu, Jian Z.; Turcu, Romulus VF; Rosso, Kevin M.; Ilton, Eugene S.; Wang, Chong M.; Sears, Jesse A.; Engelhard, Mark H.; Felmy, Andrew R.; Hoyt, David W.

    2011-07-01

    The water concentration dependence of forsterite carbonation in supercritical CO2 (scCO2) at 80°C and 76 bars was investigated by a combination of NMR, XRD, TEM and XPS. Reaction products were not detected using scCO2 alone without added H2O. When trace amounts of water were included, limited reaction was observed. Below saturation, reaction products were a mixture of partially hydrated/hydroxylated magnesium carbonates and hydroxylated silica species that were mainly in an amorphous state, forming a non-resolved layer on the forsterite surface. At water concentrations above saturation, where forsterite was in contact with both a CO2-saturated aqueous fluid and a water-saturated scCO2 fluid, solid reaction products were magnesite (MgCO3) and an amorphous polymerized SiO2 dominated by Q4, and to a lesser extent by Q3 silica coordination. Formation of these phases implies H2O initially bound in precursor hydrated/hydroxylated reaction products was liberated, inducing further reaction. Hence, for a given fluid/mineral ratio there is a water threshold above which a significant portion of the water serves in a catalytic role where more extensive carbonation reaction occurs. Defining the role of water, even in low water content environments, is therefore critical to determining the long term impact of CO2 reactivity in the subsurface.

  8. Drying Using Supercritical Fluid Technology as a Potential Method for Preparation of Chitosan Aerogel Microparticles.

    Science.gov (United States)

    Obaidat, Rana M; Tashtoush, Bassam M; Bayan, Mohammad F; Al Bustami, Rana T; Alnaief, Mohammad

    2015-12-01

    Supercritical fluid technology offers several advantages in preparation of microparticles. These include uniformity in particle size, morphology, and drug distribution without degradation of the product. One of the recent advantages is preparation of porous aerogel carrier with proper aerodynamic properties. In this study, we aimed to prepare chitosan aerogel microparticles using supercritical fluid (SCF) technology and compare that with microparticles produced by freeze drying (FD). Loading the prepared carriers with a model drug (salbutamol) was also performed. Comparisons of the particle properties and physicochemical characterizations were undertaken by evaluating particle size, density, specific surface area, and porosity. In vitro drug release studies were also investigated. The effect of many variables, such as molecular weight of chitosan oligomers, concentrations of chitosan, and concentrations of tripolyphosphate on the release, were also investigated. Chitosan aerogels were efficiently produced by SCF technology with an average particle size of 10 μm with a tapped density values around 0.12 g/mL, specific surface area (73-103) m(2)/g, and porosity (0.20-0.29) cc/g. Whereas, microparticles produced by FD method were characterized as cryogels with larger particle size (64 microns) with clear cracking at the surface. Sustained release profile was achieved for all prepared microparticles of salbutamol produced by the aforementioned methods as compared with pure drug. The results also demonstrates that chitosan molecular weight, polymer concentration, and tripolyphosphate concentration affected the release profile of salbutamol from the prepared microparticles. In conclusion, SCF technology was able to produce chitosan aerogel microparticles loaded with salbutamol that could be suitable for pulmonary drug delivery system.

  9. Effect of supercritical carbon dioxide pasteurization on natural microbiota, texture, and microstructure of fresh-cut coconut.

    Science.gov (United States)

    Ferrentino, Giovanna; Balzan, Sara; Dorigato, Andrea; Pegoretti, Alessandro; Spilimbergo, Sara

    2012-05-01

    The objective of the present study was the evaluation of the effectiveness of supercritical carbon dioxide (SC-CO(2)) as a nonthermal technology for the pasteurization of fresh-cut coconut, as an example of ready-to-eat and minimally processed food. First, the inactivation kinetics of microbiota on coconut were determined using SC-CO(2) treatments (pressures at 8 and 12 MPa, temperatures from 24 to 45 °C, treatment times from 5 to 60 min). Second, the effects of SC-CO(2) on the hardness and microstructure of fresh-cut coconut processed at the optimal conditions for microbial reduction were investigated. SC-CO(2) treatment of 15 min at 45 °C and 12 MPa induced 4 log CFU/g reductions of mesophilic microorganisms, lactic acid bacteria, total coliforms, and yeasts and molds. The hardness of coconut was not affected by the treatment but the samples developed an irregular and disorderly microstructure. Results suggested the potential of SC-CO(2) in preserving fresh-cut fruits and ready-to-eat products. © 2012 Institute of Food Technologists®

  10. Optimization of supercritical carbon dioxide extraction of essential oil from Dracocephalum kotschyi Boiss: An endangered medicinal plant in Iran.

    Science.gov (United States)

    Nejad-Sadeghi, Masoud; Taji, Saeed; Goodarznia, Iraj

    2015-11-27

    Extraction of the essential oil from a medicinal plant called Dracocephalum kotschyi Boiss was performed by green technology of supercritical carbon dioxide (SC-CO2) extraction. A Taguchi orthogonal array design with an OA16 (4(5)) matrix was used to evaluate the effects of five extraction variables: pressure of 150-310bar, temperature of 40-60°C, average particle size of 250-1000μm, CO2 flow rate of 2-10ml/s and dynamic extraction time of 30-100min. The optimal conditions to obtain the maximum extraction yield were at 240bar, 60°C, 500μm, 10ml/s and 100min. The extraction yield under the above conditions was 2.72% (w/w) which is more than two times the maximum extraction yield that has been reported for this plant in the literature using traditional extraction techniques. Results from analysis of variance (ANOVA) indicated that the CO2 flow rate and the extraction time were the most significant factors on the extraction yield by percentage contribution of 44.27 and 28.86, respectively. Finally, the chemical composition of the essential oil was evaluated by using gas chromatography-mass spectroscopy (GC-MS). Citral, p-mentha-1,3,8-triene, D-3-carene and methyl geranate were the major components identified.

  11. Extraction and isotopic analysis of medium molecular weight hydrocarbons from Murchison using supercritical carbon dioxide

    Science.gov (United States)

    Gilmour, Iain; Pillinger, Colin

    1993-03-01

    The large variety of organic compounds present in carbonaceous chondrites poses particular problems in their analysis not the least of which is terrestrial contamination. Conventional analytical approaches employ simple chromatographic techniques to fractionate the extractable compounds into broad classes of similar chemical structure. However, the use of organic solvents and their subsequent removal by evaporation results in the depletion or loss of semi-volatile compounds as well as requiring considerable preparative work to assure solvent purity. Supercritical fluids have been shown to provide a powerful alternative to conventional liquid organic solvents used for analytical extractions. A sample of Murchison from the Field Museum was analyzed. Two interior fragments were used; the first (2.85 g) was crushed in an agate pestel and mortar to a grain size of ca. 50-100 micron, the second (1.80 g) was broken into chips 3-8 mm in size. Each sample was loaded into a stainless steel bomb and placed in the extraction chamber of an Isco supercritical fluid extractor maintained at 35 C. High purity (99.9995 percent) carbon dioxide was used and was pressurized using an Isco syringe pump. The samples were extracted dynamically by flowing CO2 under pressure through the bomb and venting via a 50 micron fused filica capillary into 5 mls of hexane used as a collection solvent. The hexane was maintained at a temperature of 0.5 C. A series of extractions were done on each sample using CO2 of increasing density. The principal components extracted in each fraction are summarized.

  12. Extraction and isotopic analysis of medium molecular weight hydrocarbons from Murchison using supercritical carbon dioxide

    Science.gov (United States)

    Gilmour, Iain; Pillinger, Colin

    1993-01-01

    The large variety of organic compounds present in carbonaceous chondrites poses particular problems in their analysis not the least of which is terrestrial contamination. Conventional analytical approaches employ simple chromatographic techniques to fractionate the extractable compounds into broad classes of similar chemical structure. However, the use of organic solvents and their subsequent removal by evaporation results in the depletion or loss of semi-volatile compounds as well as requiring considerable preparative work to assure solvent purity. Supercritical fluids have been shown to provide a powerful alternative to conventional liquid organic solvents used for analytical extractions. A sample of Murchison from the Field Museum was analyzed. Two interior fragments were used; the first (2.85 g) was crushed in an agate pestel and mortar to a grain size of ca. 50-100 micron, the second (1.80 g) was broken into chips 3-8 mm in size. Each sample was loaded into a stainless steel bomb and placed in the extraction chamber of an Isco supercritical fluid extractor maintained at 35 C. High purity (99.9995 percent) carbon dioxide was used and was pressurized using an Isco syringe pump. The samples were extracted dynamically by flowing CO2 under pressure through the bomb and venting via a 50 micron fused filica capillary into 5 mls of hexane used as a collection solvent. The hexane was maintained at a temperature of 0.5 C. A series of extractions were done on each sample using CO2 of increasing density. The principal components extracted in each fraction are summarized.

  13. Extraction of microalgae derived lipids with supercritical carbon dioxide in an industrial relevant pilot plant.

    Science.gov (United States)

    Lorenzen, Jan; Igl, Nadine; Tippelt, Marlene; Stege, Andrea; Qoura, Farah; Sohling, Ulrich; Brück, Thomas

    2017-06-01

    Microalgae are capable of producing up to 70% w/w triglycerides with respect to their dry cell weight. Since microalgae utilize the greenhouse gas CO2, they can be cultivated on marginal lands and grow up to ten times faster than terrestrial plants, the generation of algae oils is a promising option for the development of sustainable bioprocesses, that are of interest for the chemical lubricant, cosmetic and food industry. For the first time we have carried out the optimization of supercritical carbon dioxide (SCCO2) mediated lipid extraction from biomass of the microalgae Scenedesmus obliquus and Scenedesmus obtusiusculus under industrrially relevant conditions. All experiments were carried out in an industrial pilot plant setting, according to current ATEX directives, with batch sizes up to 1.3 kg. Different combinations of pressure (7-80 MPa), temperature (20-200 °C) and CO2 to biomass ratio (20-200) have been tested on the dried biomass. The most efficient conditions were found to be 12 MPa pressure, a temperature of 20 °C and a CO2 to biomass ratio of 100, resulting in a high extraction efficiency of up to 92%. Since the optimized CO2 extraction still yields a crude triglyceride product that contains various algae derived contaminants, such as chlorophyll and carotenoids, a very effective and scalable purification procedure, based on cost efficient bentonite based adsorbers, was devised. In addition to the sequential extraction and purification procedure, we present a consolidated online-bleaching procedure for algae derived oils that is realized within the supercritical CO2 extraction plant.

  14. Fixed Bed Adsorption of Drugs on Silica Aerogel from Supercritical Carbon Dioxide Solutions

    OpenAIRE

    Giuseppe Caputo

    2013-01-01

    Supercritical adsorption coupled with the high adsorption capacity of silica aerogel allows the preparation of a new kind of delivery systems of poor water soluble drugs. In order to overcome drawbacks of conventional techniques where the use of liquid solvents can cause the fracture of aerogel porous structure, in this work a new adsorption process of drugs from a supercritical mixture is proposed. Adsorption takes place from a fluid solution of the drug in supercritical CO2 and ethanol as c...

  15. Direct synthesis of dimethyl carbonate and propylene glycol using potassium bicarbonate as catalyst in supercritical CO2

    Directory of Open Access Journals (Sweden)

    Wen Yicun

    2015-03-01

    Full Text Available The improved one-pot synthesis of dimethyl carbonate and propylene glycol from propylene oxide, supercritical carbon dioxide, and methanol with potassium bicarbonate as the catalyst has been reported in this paper. As far as we know, it is the first time to use potassium bicarbonate only as the catalyst in the production process which is simple and cheap. Satisfactory conversion rate of propylene oxide and yield of the products could be achieved at the optimized conditions with quite a small amount of by-products. Our new method offers an attractive choice for the production of dimethyl carbonate in large-scale industry efficiently and environmental friendly.

  16. Silicate Carbonation in Supercritical CO2 Containing Dissolved H2O: An in situ High Pressure X-Ray Diffraction Study

    Energy Technology Data Exchange (ETDEWEB)

    Schaef, Herbert T.; Miller, Quin RS; Thompson, Christopher J.; Loring, John S.; Bowden, Mark E.; Arey, Bruce W.; McGrail, B. Peter; Rosso, Kevin M.

    2013-06-30

    Technological advances have been significant in recent years for managing environmentally harmful emissions (mostly CO2) resulting from combustion of fossil fuels. Deep underground geologic formations are emerging as reasonable options for long term storage of CO2 but mechanisms controlling rock and mineral stability in contact with injected supercritical fluids containing water are relatively unknown. In this paper, we discuss mineral transformation reactions occurring between supercritical CO2 containing water and the silicate minerals forsterite (Mg2SiO4), wollastonite (CaSiO3), and enstatite (MgSiO3). This study utilizes newly developed in situ high pressure x-ray diffraction (HXRD) and in situ infra red (IR) to examine mineral transformation reactions. Forsterite and enstatite were selected as they are important minerals present in igneous and mafic rocks and have been the subject of a large number of aqueous dissolution studies that can be compared with non-aqueous fluid tests in this study. Wollastonite, classified as a pyroxenoid (similar to a pyroxene), was chosen as a suitably fast reacting proxy for examining silicate carbonation processes associated with a wet scCO2 fluid as related to geologic carbon sequestration. The experiments were conducted under modest pressures (90 to 160 bar), temperatures between 35° to 70° C, and varying concentrations of dissolved water. Under these conditions scCO2 contains up to 3,500 ppm dissolved water.

  17. Solubility of α-Tocopheryl Succinate in Supercritical Carbon Dioxide Using Offline HPLC-MS/MS Analysis.

    Science.gov (United States)

    Hybertson, Brooks M

    2007-05-01

    The solubility of the vitamin E-related compound α-tocopheryl succinate in supercritical carbon dioxide was measured at pressures ranging from (15.0 to 30.0) MPa and temperatures of (40 and 50) °C using a simple microsampling type apparatus with a 100.5 μL sample loop to remove aliquots and collect them in ethanol for off line analysis. α-Tocopheryl succinate concentrations in the collected samples were measured using HPLC-MS/MS analysis. The solubility of α-tocopheryl succinate in supercritical carbon dioxide ranged from mole fractions of 0.28 × 10(-5) at 15.0 MPa and 50 °C to 2.56 × 10(-5) at 30.0 MPa and 50 °C.

  18. Predictions of heat transfer coefficients of supercritical carbon dioxide using the overlapped type of local neural network

    Energy Technology Data Exchange (ETDEWEB)

    Junghui Chen; Kuan-Po Wang [Chung-Yuan Christian University (China). Dept. of Chemical Engineering; Ming-Tsai Liang [I-Shou University (China). Dept. of Chemical Engineering

    2005-06-01

    An overlapped type of local neural network is proposed to improve accuracy of the heat transfer coefficient estimation of the supercritical carbon dioxide. The idea of this work is to use the network to estimate the heat transfer coefficient for which there is no accurate correlation model due to the complexity of the thermo-physical properties involved around the critical region. Unlike the global approximation network (e.g. backpropagation network) and the local approximation network (e.g. the radial basis function network), the proposed network allows us to match the quick changes in the near-critical local region where the rate of heat transfer is significantly increased and to construct the global smooth perspective far away from that local region. Based on the experimental data for carbon dioxide flowing inside a heated tube at the supercritical condition, the proposed network significantly outperformed some the conventional correlation method and the traditional network models. (Author)

  19. Photocatalytic and chemical oxidation of organic compounds in supercritical carbon dioxide. Progress report for FY97

    Energy Technology Data Exchange (ETDEWEB)

    Blake, D.M.; Bryant, D.L.; Reinsch, V.

    1997-09-30

    'The background for the project is briefly reviewed and the work done during the nine months since funding was received is documented. Work began in January, 1997. A post doctoral fellow joined the team in April. The major activities completed this fiscal year were: staffing the project, design of the experimental system, procurement of components, assembly of the system. preparation of the Safe Operating Procedure and ES and H compliance, pressure testing, establishing data collection and storage methodology, and catalyst preparation. Objective The objective of the project is to develop new chemistry for the removal of organic contaminants from supercritical carbon dioxide. This has application in processes used for continuous cleaning and extraction of parts and waste materials. A secondary objective is to increase the fundamental understanding of photocatalytic chemistry. Cleaning and extraction using supercritical carbon dioxide (scCO{sub 2}) can be applied to the solution of a wide range of environmental and pollution prevention problems in the DOE complex. Work is being done that explores scCO{sub 2} in applications ranging from cleaning contaminated soil to cleaning components constructed from plutonium. The rationale for use of scCO{sub 2} are based on the benign nature, availability and low cost, attractive solvent properties, and energy efficient separation of the extracted solute from the solvent by moderate temperature or pressure changes. To date, R and D has focussed on the methods and applications of the extraction steps of the process. Little has been done that addresses methods to polish the scCO{sub 2} for recycle in the cleaning or extraction operations. In many applications it will be desirable to reduce the level of contamination from that which would occur at steady state operation of a process. This proposal addresses chemistry to achieve that. This would be an alternative to removing a fraction of the contaminated scCO{sub 2} for

  20. The Effect of Hydrous Supercritical Carbon Dioxide on the Mohr Coulomb Failure Envelope in Boise Sandstone

    Science.gov (United States)

    Choens, R. C., II; Dewers, T. A.; Ilgen, A.; Espinoza, N.; Aman, M.

    2016-12-01

    Experimental rock deformation was used to quantify the relationship between supercritical carbon dioxide (scCO2), water vapor, and failure strength in an analog for Tertiary sandstone saline formation reservoirs. Storing large volumes of carbon dioxide in depleted petroleum reservoirs and deep saline aquifers over geologic time is an important tool in mitigating effects of climate change. Carbon dioxide is injected as a supercritical phase, where it forms a buoyant plume. At brine-plume interfaces, scCO2 dissolves over time into the brine, lowering pH and perturbing the local chemical environment. Previous work has shown that the resulting geochemical changes at mineral-fluid interfaces can alter rock mechanical properties, generally causing a decrease in strength. Additionally, water from the native brine can dissolve into the scCO2 plume where it is present as humidity. This study investigates the effect of hydrous scCO2 and CO2-saturated brine on shear failure of Boise sandstone. Samples are held in a hydrostatic pressure vessel at 2250 PSI confining pressure (PC) and 70 C, and scCO2 at specific humidity is circulated through the core for 24 hours at 2000 PSI and 70 C. Experiments are conducted at relative humidity levels of 0, 14, 28, 42, 56, 70, 84, 98, and 100% relative humidity. After the scCO2 core flood is finished, triaxial compression experiments are conducted on the samples at room temperature and an axial strain rate of 10-5 sec-1. Experiments are conducted at 500, 1000, and 1500 PSI PC. The results demonstrate that water present as humidity in scCO2 can reduce failure strength and lower slopes of the Mohr-Coulomb failure envelope. These effects increase with increasing humidity, as dry scCO2 does not affect rock strength, and may be influenced by capillary condensation of water films from humid scCO2. The reductions in failure strength seen in this study could be important in predicting reservoir response to injection, reservoir caprock integrity, and

  1. Quantum Chemical Study of Supercritical Carbon Dioxide Effects on Combustion Kinetics.

    Science.gov (United States)

    Masunov, Artëm E; Wait, Elizabeth E; Atlanov, Arseniy A; Vasu, Subith S

    2017-05-18

    In oxy-fuel combustion, the pure oxygen (O2), diluted with CO2 is used as oxidant instead air. Hence, the combustion products (CO2 and H2O) are free from pollution by nitrogen oxides. Moreover, high pressures result in the near-liquid density of CO2 at supercritical state (sCO2). Unfortunately, the effects of sCO2 on the combustion kinetics are far from being understood. To assist in this understanding, in this work we are using quantum chemistry methods. Here we investigate potential energy surfaces of important combustion reactions in the presence of the carbon dioxide molecule. All transition states and reactant and product complexes are reported for three reactions: H2CO + HO2 → HCO + H2O2 (R1), 2HO2 → H2O2 + O2 (R2), and CO + OH → CO2 + H (R3). In reaction R3, covalent binding of CO2 to the OH radical and then the CO molecule opens a new pathway, including hydrogen transfer from oxygen to carbon atoms followed by CH bond dissociation. Compared to the bimolecular OH + CO mechanism, this pathway reduces the activation barrier by 5 kcal/mol and is expected to accelerate the reaction. In the case of hydroperoxyl self-reaction 2HO2 → H2O2 + O2 the intermediates, containing covalent bonds to CO2 are found not to be competitive. However, the spectator CO2 molecule can stabilize the cyclic transition state and lower the barrier by 3 kcal/mol. Formation of covalent intermediates is also discovered in the H2CO + HO2 → HCO + H2O2 reaction, but these species lead to substantially higher activation barriers, which makes them unlikely to play a role in hydrogen transfer kinetics. The van der Waals complexation with carbon dioxide also stabilizes the transition state and reduces the reaction barrier. These results indicate that the CO2 environment is likely to have a catalytic effect on combustion reactions, which needs to be included in kinetic combustion mechanisms in supercritical CO2.

  2. Biodiesel production with continuous supercritical process: non-catalytic transesterification and esterification with or without carbon dioxide.

    Science.gov (United States)

    Tsai, Yu-Ting; Lin, Ho-mu; Lee, Ming-Jer

    2013-10-01

    The non-catalytic transesterification of refined sunflower oil with supercritical methanol, in the presence of carbon dioxide, was conducted in a tubular reactor at temperatures from 553.2 to 593.2K and pressures up to 25.0 MPa. The FAME yield can be achieved up to about 0.70 at 593.2 K and 10.0 MPa in 23 min with methanol:oil of 25:1 in molar ratio. The effect of adding CO2 on the FAME yield is insignificant. The kinetic behavior of the non-catalytic esterification and transesterification of oleic acid or waste cooking oil (WCO) with supercritical methanol was also investigated. By using the supercritical process, the presence of free fatty acid (FFA) in WCO gives positive contribution to FAME production. The FAME yield of 0.90 from WCO can be achieved in 13 min at 573.2K. The kinetic data of supercritical transesterification and esterifaication were correlated well with a power-law model. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Supercritical Carbon Dioxide-Assisted Process for Well-Dispersed Silicon/Graphene Composite as a Li ion Battery Anode

    OpenAIRE

    2016-01-01

    The silicon (Si)/graphene composite has been touted as one of the most promising anode materials for lithium ion batteries. However, the optimal fabrication method for this composite remains a challenge. Here, we developed a novel method using supercritical carbon dioxide (scCO2) to intercalate Si nanoparticles into graphene nanosheets. Silicon was modified with a thin layer of polyaniline, which assisted the dispersion of graphene sheets by introducing π-π interaction. Using scCO2, well-disp...

  4. Solubilities of some recently synthesized 1,8-dihydroxy-9,10-anthraquinone derivatives in supercritical carbon dioxide.

    Science.gov (United States)

    Fat'hi, M R; Yamini, Y; Sharghi, H; Shamsipur, M

    1999-04-01

    The solubility of four recently synthesized 1,8-dihydroxy-9,10-anthraquinone derivatives, as potential complexing agents in some extraction and membrane transport experiments, have been measured in supercritical carbon dioxide. The measurements were carried out in the pressure range 120-400 atm at temperatures 35, 45, 55, 65, and 75 degrees C. The measured solubilities were correlated using the model proposed by Chrastil. The calculated results show good agreement with the experimental data.

  5. Optimizing supercritical carbon dioxide in the inactivation of bacteria in clinical solid waste by using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Hossain, Md. Sohrab [Department of Environmental Technology, School of Industrial Technology, Universiti Sains Malaysia, 11800 Penang (Malaysia); Nik Ab Rahman, Nik Norulaini [School of Distance Education, Universiti Sains Malaysia, 11800 Penang (Malaysia); Balakrishnan, Venugopal [Institute for Research in Molecular Medicine, Universiti Sains Malaysia, 11800 Penang (Malaysia); Alkarkhi, Abbas F.M. [Department of Environmental Technology, School of Industrial Technology, Universiti Sains Malaysia, 11800 Penang (Malaysia); Ahmad Rajion, Zainul [School of Dental Science, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan (Malaysia); Ab Kadir, Mohd Omar, E-mail: akmomar@usm.my [Department of Environmental Technology, School of Industrial Technology, Universiti Sains Malaysia, 11800 Penang (Malaysia)

    2015-04-15

    Highlights: • Supercritical carbon dioxide sterilization of clinical solid waste. • Inactivation of bacteria in clinical solid waste using supercritical carbon dioxide. • Reduction of the hazardous exposure of clinical solid waste. • Optimization of the supercritical carbon dioxide experimental conditions. - Abstract: Clinical solid waste (CSW) poses a challenge to health care facilities because of the presence of pathogenic microorganisms, leading to concerns in the effective sterilization of the CSW for safe handling and elimination of infectious disease transmission. In the present study, supercritical carbon dioxide (SC-CO{sub 2}) was applied to inactivate gram-positive Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, and gram-negative Escherichia coli in CSW. The effects of SC-CO{sub 2} sterilization parameters such as pressure, temperature, and time were investigated and optimized by response surface methodology (RSM). Results showed that the data were adequately fitted into the second-order polynomial model. The linear quadratic terms and interaction between pressure and temperature had significant effects on the inactivation of S. aureus, E. coli, E. faecalis, and B. subtilis in CSW. Optimum conditions for the complete inactivation of bacteria within the experimental range of the studied variables were 20 MPa, 60 °C, and 60 min. The SC-CO{sub 2}-treated bacterial cells, observed under a scanning electron microscope, showed morphological changes, including cell breakage and dislodged cell walls, which could have caused the inactivation. This espouses the inference that SC-CO{sub 2} exerts strong inactivating effects on the bacteria present in CSW, and has the potential to be used in CSW management for the safe handling and recycling-reuse of CSW materials.

  6. Coupling a Supercritical Carbon Dioxide Brayton Cycle to a Helium-Cooled Reactor.

    Energy Technology Data Exchange (ETDEWEB)

    Middleton, Bobby [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pasch, James Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Kruizenga, Alan Michael [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Walker, Matthew [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

    2016-01-01

    This report outlines the thermodynamics of a supercritical carbon dioxide (sCO2) recompression closed Brayton cycle (RCBC) coupled to a Helium-cooled nuclear reactor. The baseline reactor design for the study is the AREVA High Temperature Gas-Cooled Reactor (HTGR). Using the AREVA HTGR nominal operating parameters, an initial thermodynamic study was performed using Sandia's deterministic RCBC analysis program. Utilizing the output of the RCBC thermodynamic analysis, preliminary values of reactor power and of Helium flow rate through the reactor were calculated in Sandia's HelCO2 code. Some research regarding materials requirements was then conducted to determine aspects of corrosion related to both Helium and to sCO2 , as well as some mechanical considerations for pressures and temperatures that will be seen by the piping and other components. This analysis resulted in a list of materials-related research items that need to be conducted in the future. A short assessment of dry heat rejection advantages of sCO2> Brayton cycles was also included. This assessment lists some items that should be investigated in the future to better understand how sCO2 Brayton cycles and nuclear can maximally contribute to optimizing the water efficiency of carbon free power generation

  7. Dissolution-rate enhancement of fenofibrate by adsorption onto silica using supercritical carbon dioxide.

    Science.gov (United States)

    Sanganwar, Ganesh P; Gupta, Ram B

    2008-08-06

    Dissolution rate of a poorly water-soluble drug, fenofibrate, is increased by adsorbing the drug onto silica. The adsorption is achieved by first dissolving the drug in supercritical carbon dioxide and then depressurizing the solution onto silica. Loadings of up to 27.5 wt.% drug onto silica are obtained. Since solvents are not used in the loading process, the fenofibrate/silica formulation is free of any residual solvent, and carbon dioxide is freely removed upon depressurization. The formulation is characterized using infrared spectroscopy, ultraviolet spectroscopy, X-ray diffraction, differential scanning calorimetry and scanning electron microscopy. Based on in vitro dissolution study, a significant increase in the dissolution rate (approximately 80% drug release in 20 min) of drug-silica formulation is observed as compared to micronized fenofibrate (approximately 20% drug release in 20 min), which can be attributed to increase in the surface area and decrease in the crystallinity of drug after adsorption onto silica. Two different formulations are compared: (A) amorphous fenofibrate/silica and (B) slightly crystalline fenofibrate/silica. The second formulation is found to be more stable on storage.

  8. Application and Progress of Research on Supercritical Fluid Extraction Technology%超临界萃取技术研究现状与应用

    Institute of Scientific and Technical Information of China (English)

    周也; 田震; 王丽雯

    2012-01-01

    Bac technology of extraction and kground of supercritical fluid extraction technology was introduced and overview of the supercritical fluid extraction was also introduced. Focused on the method of enhanced industrial applications of supercritical fluid extraction technology.%简要介绍了超临界萃取技术的背景,并对超临界萃取技术做相关概述。着重介绍了强化萃取的方法和超临界萃取技术的工业应用。

  9. Relative permeabilities of supercritical CO2 and brine in carbon sequestration by a two-phase lattice Boltzmann method

    Science.gov (United States)

    Xie, Jian.-Fei.; He, S.; Zu, Y. Q.; Lamy-Chappuis, B.; Yardley, B. W. D.

    2017-08-01

    In this paper, the migration of supercritical carbon dioxide (CO2) in realistic sandstone rocks under conditions of saline aquifers, with applications to the carbon geological storage, has been investigated by a two-phase lattice Boltzmann method (LBM). Firstly the digital images of sandstone rocks were reproduced utilizing the X-ray computed microtomography (micro-CT), and high resolutions (up to 2.5 μm) were applied to the pore-scale LBM simulations. For the sake of numerical stability, the digital images were "cleaned" by closing the dead holes and removing the suspended particles in sandstone rocks. In addition, the effect of chemical reactions occurred in the carbonation process on the permeability was taken into account. For the wetting brine and non-wetting supercritical CO2 flows, they were treated as the immiscible fluids and were driven by pressure gradients in sandstone rocks. Relative permeabilities of brine and supercritical CO2 in sandstone rocks were estimated. Particularly the dynamic saturation was applied to improve the reliability of the calculations of the relative permeabilities. Moreover, the effects of the viscosity ratio of the two immiscible fluids and the resolution of digital images on the relative permeability were systematically investigated.

  10. Supercritical fluid extraction

    Science.gov (United States)

    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.

  11. Sustainable Production of Cannabinoids with Supercritical Carbon Dioxide Technologies

    NARCIS (Netherlands)

    Perrotin-Brunel, H.

    2011-01-01

    This thesis concerns the production of natural compounds from plant material for pharmaceutical and food applications. It describes the production (extraction and isolation) of cannabinoids, the active components present in cannabis. Many cannabinoids have medicinal properties but not all cannabinoi

  12. Production of polyhydroxyalkanoates from spent coffee grounds oil obtained by supercritical fluid extraction technology.

    Science.gov (United States)

    Cruz, Madalena V; Paiva, Alexandre; Lisboa, Pedro; Freitas, Filomena; Alves, Vítor D; Simões, Pedro; Barreiros, Susana; Reis, Maria A M

    2014-04-01

    Spent coffee grounds (SCG) oil was obtained by supercritical carbon dioxide (scCO2) extraction in a pilot plant apparatus, with an oil extraction yield of 90% at a 35kgkg(-1) CO2/SCG ratio. Cupriavidus necator DSM 428 was cultivated in 2L bioreactor using extracted SCG oil as sole carbon source for production of polyhydroxyalkanoates. The culture reached a cell dry weight of 16.7gL(-1) with a polymer content of 78.4% (w/w). The volumetric polymer productivity and oil yield were 4.7gL(-1)day(-1) and 0.77gg(-1), respectively. The polymer produced was a homopolymer of 3-hydroxybutyrate with an average molecular weight of 2.34×10(5) and a polydispersity index of 1.2. The polymer exhibited brittle behaviour, with very low elongation at break (1.3%), tensile strength at break of 16MPa and Young's Modulus of 1.0GPa. Results show that SCG can be a bioresource for polyhydroxyalkanoates production with interesting properties. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Selective hydrogenation of citral over Au-based bimetallic catalysts in supercritical carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Selective hydrogenation of citral was investigated over Au-based bimetallic catalysts in the environmentally benign supercritical carbon dioxide (scCO2) medium.The catalytic performances were different in citral hydrogenation when Pd or Ru was mixed (physically and chemically) with Au.Compared with the corresponding monometallic catalyst,the total conversion and the selectivity to citronellal (CAL) were significantly enhanced over TiO2 supported Pd and Au bimetallic catalysts (physically and chemically mixed);however,the conversion and selectivity did not change when Ru was physically mixed with Au catalyst compared to the monometallic Ru/TiO2,and the chemically mixed Ru-Au/TiO2 catalyst did not show any activity.The effect of CO2 pressure on the conversion of citral and product selectivity was significantly different over the Au/TiO2,Pd-Au/TiO2,and Pd/TiO2 catalysts.It was assumed to be ascribed to the difference in the interactions between Au,Pd nanoparticles and CO2 under different CO2 pressures.

  14. Hanford/Rocky Flats collaboration on development of supercritical carbon dioxide extraction to treat mixed waste

    Energy Technology Data Exchange (ETDEWEB)

    Hendrickson, D.W.; Biyani, R.K. [Westinghouse Hanford Co., Richland, WA (United States); Brown, C.M.; Teter, W.L. [Kaiser-Hill Co., Golden, CO (United States)

    1995-11-01

    Proposals for demonstration work under the Department of Energy`s Mixed Waste Focus Area, during the 1996 through 1997 fiscal years included two applications of supercritical carbon dioxide to mixed waste pretreatment. These proposals included task RF15MW58 of Rocky Flats and task RL46MW59 of Hanford. Analysis of compatibilities in wastes and work scopes yielded an expectation of substantial collaboration between sites whereby Hanford waste streams may undergo demonstration testing at Rocky Flats, thereby eliminating the need for test facilities at Hanford. This form of collaboration is premised the continued deployment at Rocky Flats and the capability for Hanford samples to be treated at Rocky Flats. The recent creation of a thermal treatment contract for a facility near Hanford may alleviate the need to conduct organic extraction upon Rocky Flats wastes by providing a cost effective thermal treatment alternative, however, some waste streams at Hanford will continue to require organic extraction. Final site waste stream treatment locations are not within the scope of this document.

  15. Isolation of anacardic acid from natural cashew nut shell liquid (CNSL) using supercritical carbon dioxide.

    Science.gov (United States)

    Philip, Joseph Y N; Da Cruz Francisco, José; Dey, Estera S; Buchweishaija, Joseph; Mkayula, Lupituko L; Ye, Lei

    2008-10-22

    Solvent extracted cashew nut shell liquid (CNSL), conventionally known as natural CNSL, is a mixture of several alkenyl phenols. One of these alkenyl phenols is anacardic acid, which is present at the highest concentration. In view of anticipated industrial applications of anacardic acid, the objective of this work was to isolate anacardic acid from natural CNSL by supercritical carbon dioxide (scCO 2). In this study, the solubility data for natural CNSL in scCO 2 under a range of operating conditions of pressure (100, 200, and 300 bar), temperature (40 and 50 degrees C), and CO 2 flow rate (5, 10, and 15 g min (-1)) were established. The best scCO 2 working conditions were found to be 50 degrees C and 300 bar at a flow rate of 5 g min (-1) CO 2. Using 3 g of sample (CNSL/solid adsorbent = 1/2) under these scCO 2 conditions, it was possible to quantitatively isolate high purity anacardic acid from crude natural CNSL (82% of total anacardic acid) within 150 min. The anacardic acid isolated by scCO 2 was analyzed by different spectroscopic techniques (UV-vis, FT-IR, and (1)H NMR) and HPLC analysis, indicating that the anacardic acid isolated by scCO 2 has better quality than that obtained through a conventional method involving several chemical conversion steps.

  16. Efficacy of supercritical carbon dioxide for nonthermal inactivation of Escherichia coli K12 in apple cider.

    Science.gov (United States)

    Yuk, Hyun-Gyun; Geveke, David J; Zhang, Howard Q

    2010-03-31

    This study evaluated the efficacy of a supercritical carbon dioxide (SCCO(2)) system with a gas-liquid porous metal contactor for eliminating Escherichia coli K12 in apple cider. Pasteurized, preservative-free apple cider was inoculated with E. coli K12 and processed using the SCCO(2) system at CO(2) concentrations of 0-10% (wt.%, g CO(2)/100g product), outlet temperatures of 34, 38, and 42 degrees C, a system pressure of 7.6 MPa, and a flow rate of 1L/min. Increased CO(2) concentrations and temperatures significantly (Pcider. SEM observations showed morphological changes in the cell envelope after SCCO(2) processing. At a processing condition of 8% and 38 degrees C, the reduction of E. coli was 6.03 log and the sublethal injury of the survivors was 84%. The regrowth or survival of E. coli in SCCO(2) processed apple cider was not observed during storage for 28 days at 4, 8, and 20 degrees C. Thus this study showed the potential of SCCO(2) processing with a gas-liquid porous metal contactor for the nonthermal pasteurization of apple cider. Copyright 2009. Published by Elsevier B.V.

  17. Hydrogenation of Anthracene in Supercritical Carbon Dioxide Solvent Using Ni Supported on Hβ-Zeolite Catalyst

    Directory of Open Access Journals (Sweden)

    Ashraf Aly Hassan

    2012-01-01

    Full Text Available Catalytic hydrogenation of anthracene was studied over Ni supported on Hβ-zeolite catalyst under supercritical carbon dioxide (sc-CO2 solvent. Hydrogenation of anthracene in sc-CO2 yielded 100% conversion at 100 °C, which is attributed to the reduced mass transfer limitations, and increased solubility of H2 and substrate in the reaction medium. The total pressure of 7 MPa was found to be optimum for high selectivity of octahydroanthracene (OHA. The conversion and selectivity for OHA increased with an increase in H2 partial pressure, which is attributed to higher concentration of hydrogen atoms at higher H2 pressures. The selectivity reduced the pressure below 7 MPa because of enhanced desorption of the tetrahydro-molecules and intermediates from Ni active sites, due to higher solubility of the surface species in sc-CO2. The selectivity of OHA increased with the increase in catalyst weight and reaction time. The rate of hydrogenation of anthracene was compared with that found for napthalene and phenanthrene. The use of acetonitrile as co-solvent or expanded liquid with CO2 decreased the catalytic activity.

  18. Supercritical carbon dioxide extraction of methylxanthines from maté tea leaves

    Directory of Open Access Journals (Sweden)

    Saldaña M.D.A.

    2000-01-01

    Full Text Available Methylxanthines are alkaloids found in natural products such as tea, coffee and guaraná. These alkaloids are commonly used in cola drinks and pharmaceutical products due principally to their stimulant and diuretic effects on the human organism. In this work, experimental data on the supercritical CO2 extraction of caffeine, theophylline and theobromine from herbal maté tea, a beverage traditionally consumed by the gauchos of southern Brazil, the Argentine, Paraguay and Uruguay, were obtained using high pressure extraction equipment that allows adequate control of temperature and pressure. The continuous extraction/fractionation of maté tea leaves, Ilex paraguariensis in natura using carbon dioxide was carried out at 313.2 and 343.2 K and pressures of 13.8 and 25.5 MPa. Extraction/fractionation curves revealed the large influence of temperature and pressure on extraction yield. CO2 was also found to show a higher selectivity for caffeine than for theophylline and theobromine.

  19. Supercritical Carbon Dioxide Assisted Processing of Silica/PMMA Nanocomposite Foams

    Science.gov (United States)

    Rende, Deniz; Schadler, Linda S.; Ozisik, Rahmi

    2012-02-01

    Polymer nanocomposite foams receive considerable attention in both scientific and industrial communities. These structures are defined as closed or open cells (pores) surrounded by bulk material and are widely observed in nature in the form of bone structure, sponge, corals and natural cork. Inspired by these materials, polymer nanocomposite foams are widely used in advanced applications, such as bone scaffolds, food packaging and transportation materials due to their lightweight and enhanced mechanical, thermal, and electrical properties compared to bulk polymer foams. The presence of the nanosized fillers facilitates heterogeneous bubble nucleation as a result, the number of bubbles increases while the average bubble size decreases. Therefore, the foam morphology can be controlled by the size, concentration, and surface chemistry of the nanofiller. In the current study, we used supercritical carbon dioxide as a foaming agent for silica/poly(methyl methacrylate), PMMA, foams. The silica nanoparticles were chemically modified by fluoroalkane chains to make them CO2-philic. The surface coverage was controlled via tethering density, and the effect of silica surface coverage and concentration on foam morphology was investigated through scanning electron microscopy and image processing. Results indicated that nanofiller concentration and filler surface chemistry (CO2-philicity) had tremendous effect on foam morphology but surface coverage did not have any effect.

  20. Supercritical Carbon Dioxide Extraction of Bioactive Compounds from Ampelopsis grossedentata Stems: Process Optimization and Antioxidant Activity

    Directory of Open Access Journals (Sweden)

    Da Sun

    2011-10-01

    Full Text Available Supercritical carbon dioxide (SC-CO2 extraction of bioactive compounds including flavonoids and phenolics from Ampelopsis grossedentata stems was carried out. Extraction parameters such as pressure, temperature, dynamic time and modifier, were optimized using an orthogonal array design of L9 (34, and antioxidant activities of the extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH free radical scavenging assay and ferrous ion chelating (FIC assay. The best conditions obtained for SC-CO2 extraction of flavonoids was 250 bar, 40 °C, 50 min, and with a modifier of methanol/ethanol (1:3, v/v, and that for phenolics extraction was 250 bar, 40 °C, 50 min, and with a modifier of methanol/ethanol (1:1, v/v. Meantime, flavonoids and phenolics were found to be mainly responsible for the DPPH scavenging activity of the extracts, but not for the chelating activity on ferrous ion according to Pearson correlation analysis. Furthermore, several unreported flavonoids such as apigenin, vitexin, luteolin, etc., have been detected in the extracts from A. grossedentata stems.

  1. Polyphenol-Retaining Decaffeinated Cocoa Powder Obtained by Supercritical Carbon Dioxide Extraction and Its Antioxidant Activity

    Directory of Open Access Journals (Sweden)

    Kinji Kobori

    2013-10-01

    Full Text Available Cocoa beans contain many functional ingredients such as theobromine and polyphenols, but also contain a relatively high amount of caffeine, which can negatively impact human health. It is therefore desirable to reduce caffeine levels in cocoa powder used to make chocolate or cocoa beverages while retaining functional ingredients. We have established conditions for supercritical carbon dioxide (SCCO2 extraction that remove 80.1% of the caffeine from cocoa powder while retaining theobromine (94.1% and polyphenols (84.7%. The antioxidant activity of the decaffeinated cocoa powder (DCP made with this optimized SCCO2 extraction method was 85.3% that of non-processed cocoa powder. The total procyanidin and total polyphenol concentrations of the DCPs resulting from various SCCO2 extractions showed a significant positive correlation with oxygen radical absorbance capacity (ORAC. The correlation coefficient between total polyphenols and ORAC was higher than that between total procyanidins and ORAC; thus, the concentration of total polyphenols might be a greater factor in the antioxidant activity of DCP. These results indicate that we could remove large quantities of caffeine from conventional high-cocoa products while retaining the functional benefits of high polyphenol content. This SCCO2 extraction method is expected to be applicable high-cocoa products, such as dark chocolate.

  2. Polyphenol-Retaining Decaffeinated Cocoa Powder Obtained by Supercritical Carbon Dioxide Extraction and Its Antioxidant Activity.

    Science.gov (United States)

    Kobori, Kinji; Maruta, Yuto; Mineo, Shigeru; Shigematsu, Toru; Hirayama, Masao

    2013-10-14

    Cocoa beans contain many functional ingredients such as theobromine and polyphenols, but also contain a relatively high amount of caffeine, which can negatively impact human health. It is therefore desirable to reduce caffeine levels in cocoa powder used to make chocolate or cocoa beverages while retaining functional ingredients. We have established conditions for supercritical carbon dioxide (SCCO₂) extraction that remove 80.1% of the caffeine from cocoa powder while retaining theobromine (94.1%) and polyphenols (84.7%). The antioxidant activity of the decaffeinated cocoa powder (DCP) made with this optimized SCCO₂ extraction method was 85.3% that of non-processed cocoa powder. The total procyanidin and total polyphenol concentrations of the DCPs resulting from various SCCO₂ extractions showed a significant positive correlation with oxygen radical absorbance capacity (ORAC). The correlation coefficient between total polyphenols and ORAC was higher than that between total procyanidins and ORAC; thus, the concentration of total polyphenols might be a greater factor in the antioxidant activity of DCP. These results indicate that we could remove large quantities of caffeine from conventional high-cocoa products while retaining the functional benefits of high polyphenol content. This SCCO₂ extraction method is expected to be applicable high-cocoa products, such as dark chocolate.

  3. Chemical Composition and Antioxidant/Antimicrobial Activities in Supercritical Carbon Dioxide Fluid Extract of Gloiopeltis tenax

    Directory of Open Access Journals (Sweden)

    Jiaojiao Zheng

    2012-11-01

    Full Text Available Gloiopeltis tenax (G. tenax is widely distributed along the Chinese coastal areas and is commonly used in the treatment of diarrhea and colitis. This study aimed at investigating the bioactivities of the volatile constituents in G. tenax. We extracted the essential constituents of G. tenax by supercritical carbon dioxide extraction (CO2-SFE, then identified and analyzed the constituents by gas chromatography-mass spectrometry (GC-MS. In total, 30 components were identified in the G. tenax extract. The components showed remarkable antioxidant activity (radical scavenging activity of 2,2-diphenyl-1-picrylhydrazyl (DPPH, lipid peroxidation inhibition capacity (in a β-carotene/linoleic acid-coupled oxidation reaction, and hydroxyl radical-scavenging activity (by deoxyribose degradation by iron-dependent hydroxyl radical, compared to butylated hydroxytoluene. In microdilution assays, G. tenax extracts showed a moderate inhibitory effects on Staphyloccocus aureus (minimum inhibitory concentration (MIC = 3.9 mg/mL, Enterococcus faecalis (7.8 mg/mL, Pseudomonas aeruginosa (15.6 mg/mL, and Escherichia coli (3.9 mg/mL. Antioxidant and antimicrobial activities of G. tenax were related to the active chemical composition. These results suggest that the CO2-SFE extract from G. tenax has potential to be used as a natural antioxidant and antimicrobial agent in food processing.

  4. Clay exfoliation and polymer/clay aerogels by supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    Simona eLongo

    2013-11-01

    Full Text Available Supercritical carbon dioxide (scCO2 treatments of a montmorillonite (MMT intercalated with ammonium cations bearing two long hydrocarbon tails (organo-modified MMT, OMMT led to OMMT exfoliation, with loss of the long-range order in the packing of the hydrocarbon tails and maintenance of the long-range order in the clay layers. The intercalated and the derived exfoliated OMMT have been deeply characterized, mainly by X-ray diffraction analyses. Monolithic composite aerogels, with large amounts of both intercalated and exfoliated OMMT and including the nanoporous-crystalline δ form of syndiotactic polystyrene (s-PS, have been prepared, by scCO2 extractions of s-PS-based gels. Also for high OMMT content, the gel and aerogel preparation procedures occur without re-aggregation of the exfoliated clay, which is instead observed for other kinds of polymer processing. Aerogels with the exfoliated OMMT have more even dispersion of the clay layers, higher elastic modulus and larger surface area than aerogels with the intercalated OMMT. Extremely light materials with relevant transport properties could be prepared. Moreover, s-PS-based aerogels with exfoliated OMMT could be helpful for the handling of exfoliated clay minerals.

  5. Supercritical carbon dioxide interpolymer complexes improve survival of B. longum Bb-46 in simulated gastrointestinal fluids.

    Science.gov (United States)

    Thantsha, Mapitsi S; Cloete, Thomas E; Moolman, Francis S; Labuschagne, Philip W

    2009-01-31

    Gastric acidity is the main factor affecting viability of probiotics in the gastrointestinal tract (GIT). This study investigated the survival in simulated gastrointestinal fluids of Bifidobacterium longum Bb-46 encapsulated in interpolymer complexes formed in supercritical carbon dioxide (scCO(2)). Bacteria were exposed sequentially to simulated gastric fluid (SGF, pH 2) for 2 h and simulated intestinal fluid (SIF, pH 6.8) for 6 or 24 h. Total encapsulated bacteria were determined by suspending 1 g of product in SIF for 6 h at 37 degrees C prior to plating out. Plates were incubated anaerobically at 37 degrees C for 72 h. The interpolymer complex displayed pH-responsive release properties, with little to no release in SGF and substantial release in SIF. There was a limited reduction in viable counts at the end of exposure period due to encapsulation. Protection efficiency of the interpolymer complex was improved by addition of glyceryl monostearate (GMS). Gelatine capsules delayed release of bacteria from the interpolymer complex thus minimizing time of exposure to the detrimental conditions. Use of poly(caprolactone) (PCL), ethylene oxide-propylene oxide triblock copolymer (PEO-PPO-PEO) decreased the protection efficiency of the matrix. Interpolymer complex encapsulation showed potential for protection of probiotics and therefore for application in food and pharmaceuticals.

  6. Chemical composition of Nigella sativa L. seed extracts obtained by supercritical carbon dioxide.

    Science.gov (United States)

    Tiruppur Venkatachallam, Suresh Kumar; Pattekhan, Hajimalang; Divakar, Soundar; Kadimi, Udaya Sankar

    2010-12-01

    Chemical composition of black cumin (Nigella sativa L.) seed extracts obtained by supercritical carbon dioxide at two different conditions that result in total extract (28 MPa/50°C, SFE 1) and major volatile part (12 MPa/40°C, SFE 2) and essential oil obtained by hydrodistillation of SFE-1 (HD SFE). SFE have been carried out to characterize the compounds and the variation of quinones and phenolics. The extracts were analysed by GC and GC-MS and the presence of phenolic compounds was further confirmed by 2D HSQCT (1)H and (13)C NMR spectroscopy. Forty-seven volatile compounds were detected where sixteen compounds were reported for the first time in the oil of this seed. Moreover, thymoquinone (TQ), dithymoquinone (DTQ), thymohydroquinone (THQ) and thymol (THY) were the major phenolic compounds. It can be concluded that the chemical composition of extracts obtained by SC CO2 extraction of the seeds showed better recovery of phenolic compounds than HD SFE and proved the occurrence of thermally labile or photosensitive bioactive volatiles of four major quinonic phenol compounds.

  7. Grafting of poly (lactic acid) with maleic anhydride using supercritical carbon dioxide

    Science.gov (United States)

    Khankrua, R.; Pivsa-Art, S.; Hiroyuki, H.; Suttiruengwong, S.

    2015-07-01

    The aim of this work was to modify poly lactic acid (PLA) via free radical grafting with maleic anhydride (MA) by using supercritical carbon dioxide (SCCO2). Benzoyl peroxide (BPO) was used as an initiator. The solubility of MA in SCCO2 was first determined to estimate the suitable grafting conditions and equilibrium. From the solubility study of MA in SCCO2, it was found that the solubility of MA in SCCO2 increased with the increasing pressure and dissolution time. PLA films were first prepared by compression molding. The ratio of MA to BPO was 2:1. The reaction temperature and pressure were 70°C and 100 bar respectively. The grafting reaction and the degree of grafting were characterized by nuclear magnetic resonance (NMR) spectroscopy and titration, respectively. Scanning electron microscope (SEM) technique and contact angle were used to confirm the changes in physical properties of PLA film grafted MA. NMR spectrum indicated that the grafting of MA onto PLA was successively achieved. Degree of grafting by using SCCO2 was as high as 0.98%. This provided rather high grafting degree compared with other processes. SEM pictures showed the rough surface structure on modified PLA film. In addition, contact angle results showed an improvement of the hydrophilicity by maleic anhydride grafting onto polymers.

  8. Supercritical carbon dioxide extraction of porogens for the preparation of ultralow-dielectric-constant films

    Energy Technology Data Exchange (ETDEWEB)

    Toney, Michael F

    2003-06-20

    Supercritical carbon dioxide (SCCO2) extraction of a CO{sub 2}-soluble poly(propylene glycol) (PPG) porogen from poly(methylsilsesquioxane) (PMSSQ) cured to temperatures adequate to initiate matrix condensation, but still below the decomposition temperature of the porogen is demonstrated to produce nanoporous, ultralow dielectric constant thin films. Both closed and open cell porous structures were prepared simply by varying the porogen load in the organic/inorganic hybrid films. The porogen loads investigated in the present work ranged from 25-55 wt.%. Structural characterization of the samples conducted using transmission electron microscope (TEM), small angle X-ray scattering (SAXS) and Fourier transform infrared spectroscopy (FTIR) confirms the successful extraction of the porogen from the PMSSQ matrix at relatively low temperatures ({le} 200 C). The standard thermal decomposition process is performed at much higher temperatures (typically in the range of 400 C-450 C). The values of dielectric constants and refractive indices measured are in good agreement with the structural properties of these samples.

  9. Counter flow induced draft cooling tower option for supercritical carbon dioxide Brayton cycle

    Energy Technology Data Exchange (ETDEWEB)

    Pidaparti, Sandeep R., E-mail: sandeep.pidaparti@gmail.com [Georgia Institute of Technology, George W. Woodruff School of Mechanical Engineering, Atlanta, GA 30332 (United States); Moisseytsev, Anton; Sienicki, James J. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Ranjan, Devesh, E-mail: devesh.ranjan@me.gatech.edu [Georgia Institute of Technology, George W. Woodruff School of Mechanical Engineering, Atlanta, GA 30332 (United States)

    2015-12-15

    Highlights: • A code was developed to investigate the various aspects of using cooling tower for S-CO{sub 2} Brayton cycles. • Cooling tower option to reject heat is quantitatively compared to the direct water cooling and dry air cooling options. • Optimum water conditions resulting in minimal plant capital cost per unit power consumption are calculated. - Abstract: A simplified qualitative analysis was performed to investigate the possibility of using counter flow induced draft cooling tower option to reject heat from the supercritical carbon dioxide Brayton cycle for advanced fast reactor (AFR)-100 and advanced burner reactor (ABR)-1000 plants. A code was developed to estimate the tower dimensions, power and water consumption, and to perform economic analysis. The code developed was verified against a vendor provided quotation and is used to understand the effect of ambient air and water conditions on the design of cooling tower. The calculations indicated that there exists optimum water conditions for given ambient air conditions which will result in minimum power consumption, thereby increasing the cycle efficiency. A cost-based optimization technique is used to estimate the optimum water conditions which will improve the overall plant economics. A comparison of different cooling options for the S-CO{sub 2} cycle indicated that the cooling tower option is a much more practical and economical option compared to the dry air cooling or direct water cooling options.

  10. Preparation of conductive polypyrrole (PPy) composites under supercritical carbon dioxide conditions

    Institute of Scientific and Technical Information of China (English)

    LI Gang; LIAO Xia; SUN Xinghua; YU Jian; HE Jiasong

    2007-01-01

    Electrically conductive composites were prepared via the chemical oxidative polymerization of the pyrrole monomer in polystyrene (PS) and zinc neutralized sulfonated polystyrene (Zn-SPS) films under supercritical carbon dioxide (SC-CO2) conditions.The strong swelling effect of SCCO2 made polypyrrole (PPy) particles not only form on the surface,but also become incorporated into the film,resulting in a homogeneous structure with a relatively higher conductivity.By comparison,the composite prepared in aqueous solutions shows a skin-core structure and a conductivity of 3 to 4 orders of magnitude lower than that of the former due to the diffusion-controlled process of the pyrrole monomer.The percolation thresholds of PS/PPy and Zn-SPS/PPy composites were 6.2% and 2.7% of the volume fraction of PPy,respectively,much lower than the theoretically predicted value of 16%.Moreover,the conductive composites prepared under SC-CO2 conditions showed higher thermal stability,especially in the high-temperature region.

  11. Destruction of OPA from munitions demilitarization in supercritical water oxidation: kinetics of total organic carbon disappearance.

    Science.gov (United States)

    Veriansyah, Bambang; Kim, Jae-Duck; Lee, Jong-Chol; Hong, Deasik

    2006-01-01

    The destruction of OPA from munitions demilitarization has been accomplished in supercritical water oxidation (SCWO) with oxygen as oxidant in an isothermal continuous-flow reactor. The experiments were conducted at a temperature of 689-887 K and a fixed pressure of 25 MPa, with a residence time that ranged from 7 s to 14 s. The destruction efficiency was measured by total organic carbon (TOC) conversion. At the reaction condition, the initial TOC concentrations of OPA were varied from 1.41 mmol/L to 19.57 mmol/L and the oxygen concentrations were varied from 15.03 mmol/L to 81.85 mmol/L. Experimental data showed that all the TOC conversions were >80% under the above experimental conditions. The kinetics of TOC disappearance, which is essential for the design, optimization, and control of reliable commercial SCWO reactor was developed by taking into account the dependence of the oxidant and TOC concentration on the reaction rate. A global TOC disappearance rates expression was regressed from the data of 38 experiments, to a 95% confidence level. The resulting activation energy was determined to be 44.01 +/- 1.52 kJ/mol, and the pre-exponential factor was (1.67 +/- 0.45) x 10(2) L(1.14) mmol(-0.14) s(-1). The reaction orders for the TOC and the oxidant were 0.98 +/- 0.01 and 0.16 +/- 0.02, respectively.

  12. Supercritical carbon dioxide (SC-CO2) extraction of essential oil from Swietenia mahagoni seeds

    Science.gov (United States)

    Norodin, N. S. M.; Salleh, L. M.; Hartati; Mustafa, N. M.

    2016-11-01

    Swietenia mahagoni (Mahogany) is a traditional plant that is rich with bioactive compounds. In this study, process parameters such as particle size, extraction time, solvent flowrate, temperature and pressure were studied on the extraction of essential oil from Swietenia mahagoni seeds by using supercritical carbon dioxide (SC-CO2) extraction. Swietenia mahagoni seeds was extracted at a pressure of 20-30 MPa and a temperature of 40-60°C. The effect of particle size on overall extraction of essential oil was done at 30 MPa and 50°C while the extraction time of essential oil at various temperatures and at a constant pressure of 30 MPa was studied. Meanwhile, the effect of flowrate CO2 was determined at the flowrate of 2, 3 and 4 ml/min. From the experimental data, the extraction time of 120 minutes, particle size of 0.5 mm, the flowrate of CO2 of 4 ml/min, at a pressure of 30 MPa and the temperature of 60°C were the best conditions to obtain the highest yield of essential oil.

  13. Hanford/Rocky Flats collaboration on development of supercritical carbon dioxide extraction to treat mixed waste

    Energy Technology Data Exchange (ETDEWEB)

    Hendrickson, D.W.; Biyani, R.K. [Westinghouse Hanford Co., Richland, WA (United States); Brown, C.M.; Teter, W.L. [Kaiser-Hill Co., Golden, CO (United States)

    1995-11-01

    Proposals for demonstration work under the Department of Energy`s Mixed Waste Focus Area, during the 1996 through 1997 fiscal years included two applications of supercritical carbon dioxide to mixed waste pretreatment. These proposals included task RF15MW58 of Rocky Flats and task RL46MW59 of Hanford. Analysis of compatibilities in wastes and work scopes yielded an expectation of substantial collaboration between sites whereby Hanford waste streams may undergo demonstration testing at Rocky Flats, thereby eliminating the need for test facilities at Hanford. This form of collaboration is premised the continued deployment at Rocky Flats and the capability for Hanford samples to be treated at Rocky Flats. The recent creation of a thermal treatment contract for a facility near Hanford may alleviate the need to conduct organic extraction upon Rocky Flats wastes by providing a cost effective thermal treatment alternative, however, some waste streams at Hanford will continue to require organic extraction. Final site waste stream treatment locations are not within the scope of this document.

  14. Electroless Ni-B deposition from an emulsified supercritical carbon dioxide bath

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hung-Yu; Chung, Sung-Ting; Chuang, Yan-Chi [Department of Materials Science and Engineering, National Chung Kung University, Tainan 70101, Taiwan (China); Tsai, Wen-Ta, E-mail: wttsai@mail.ncku.edu.t [Department of Materials Science and Engineering, National Chung Kung University, Tainan 70101, Taiwan (China)

    2010-10-01

    The electroless deposition of boron-containing Ni (EN-B) film from a supercritical carbon dioxide (sc-CO{sub 2}) bath was introduced. The deposition rate in sc-CO{sub 2} bath was one order of magnitude lower than that at ambient pressure without the presence of sc-CO{sub 2}. A more uniform chemical composition of the EN-B film could be obtained if it was deposited in the sc-CO{sub 2} bath. X-ray diffraction analyses revealed that the as-deposited film was amorphous in nature, despite of the deposition condition. Deposition defects such as cracks and voids could be avoided if the deposition was conducted in the sc-CO{sub 2} bath. Crystallization and boride precipitation were found after heat treatment at 400 {sup o}C for 1 h. The EN-B film deposited from the sc-CO{sub 2} bath had a higher hardness as compared with that of the normal EN-B coating. A substantial increase in hardness was obtained due to boride precipitation.

  15. Microstructure and Electrical Conductivity of CNTs/PMMA Nanocomposite Foams Foaming by Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    YUAN Huan; XIONG Yuanlu; LUO Guoqiang; LI Meijuan; SHEN Qiang; ZHANG Lianmeng

    2016-01-01

    The carbon nanotubes (CNTs)/ polymethylmethacrylate (PMMA) nanocomposite foams were prepared by the anti-solvent precipitation and supercritical foaming method. The morphology and the electrical conductivity of the foams with different kinds of CNTs were investigated. The experimental results showed that all the foams had uniform cell structure, and the cell size changed from 1.9 to 10 μm when the foaming temperature ranged from 50℃ to 95℃. With small cell size (1.9-4.0 μm), the conductivities of the foams were 3.34×10-6-4.16×10-6 S/cm compared with the solid matrix since the introduction of micro cells did not destroy the conductive network. However, when the cell size was biger (4.5-10 μm), the aspect ratio of the CNTs played the dominant role of the conductivity. The foams with short CNTs had higher conductivity, since the short CNTs were hard to stretch and snap by the cells and can well-dispersed in the cell wall and cell edges. The results of this work provided a novel material design method for conductive foams based on the rule of both microstructure and aspect ratio of the CNTs.

  16. Fabrication of water-repellent cellulose fiber coated with magnetic nanoparticles under supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Xu Shengjie; Shen Danping; Wu Peiyi, E-mail: peiyiwu@fudan.edu.cn [Fudan University, State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Laboratory of Advanced Materials (China)

    2013-04-15

    Hematite nanoparticle-coated magnetic composite fiber was prepared in supercritical carbon dioxide (scCO{sub 2}). With the help of scCO{sub 2}, cellulose did not need to be dissolved and regenerated and it could be in any form (e.g., cotton wool, filter paper, textile, etc.). The penetrating and swelling effect of scCO{sub 2}, the slowing reaction rate of weak alkalis, and the template effect of cellulose fibers were discovered to be the key factors for the fabrication of ordered cellulose/Fe{sub 2}O{sub 3} composite fibers. The structures of the composite fibers as well as the layers of Fe{sub 2}O{sub 3} particles were characterized by means of scanning/transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman investigation. It was found that {alpha}-Fe{sub 2}O{sub 3} granules which ranged from 30 to 85 nm with average diameter around 55 nm would be generated on the surface of cellulose fibers via potassium acetate, while irregular square prisms (ranged from 200 to 600 nm) which were composed of smaller nanoparticles ({approx}10 nm) would be fabricated via urea. And, the obtained composite was highly water repellent with superparamagnetic or ferromagnetic properties.

  17. Isolation and characterization of lecithin from squid (Todarodes pacificus) viscera deoiled by supercritical carbon dioxide extraction.

    Science.gov (United States)

    Uddin, Md Salim; Kishimura, Hideki; Chun, Byung-Soo

    2011-03-01

    Marine lecithin was isolated and characterized from squid (Todarodes pacificus) viscera residues deoiled by supercritical carbon dioxide (SC-CO(2)) extraction. SC-CO(2) extraction was carried out to extract the oil from squid viscera at different temperatures (35 to 45 °C) and pressures (15 to 25 MPa). The extraction yield was higher at highest temperature and pressure. The major phospholipids of squid viscera lecithin were quantified by high-performance liquid chromatography (HPLC). Phosphatidylcholine (PC; 80.5% ± 0.7%) and phosphatidylethanolamine (PE; 13.2% ± 0.2%) were the main phospholipids. Thin layer chromatography (TLC) was performed to purify the individual phospholipids. The fatty acid compositions of lecithin, PC and PE were analyzed by gas chromatography (GC). A significant amount of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were present in both phospholipids of PC and PE. Emulsions of lecithin in water were prepared through the use of a homogenizer. The oxidative stability of squid viscera lecithin was high in spite of its high concentration of long-chain polyunsaturated fatty acids. Squid viscera are discarded as a waste by fish processing industry. Since lecithin from squid viscera contains higher amounts of polyunsaturated fatty acids, it may have promising effect to use in food, pharmaceutical, and cosmetic industries.

  18. Cobalt-Mediated Radical Polymerization of Vinyl Acetate and Acrylonitrile in Supercritical Carbon Dioxide.

    Science.gov (United States)

    Kermagoret, Anthony; Chau, Ngoc Do Quyen; Grignard, Bruno; Cordella, Daniela; Debuigne, Antoine; Jérôme, Christine; Detrembleur, Christophe

    2016-03-01

    Cobalt-mediated radical polymerization (CMRP) of vinyl acetate (VAc) is successfully achieved in supercritical carbon dioxide (scCO2). CMRP of VAc is conducted using an alkyl-cobalt(III) adduct that is soluble in scCO2. Kinetics studies coupled to visual observations of the polymerization medium highlight that the melt viscosity and PVAc molar mass (Mn) are key parameters that affect the CMRP in scCO2. It is noticed that CMRP is controlled for Mn up to 10 000 g mol(-1), but loss of control is progressively observed for higher molar masses when PVAc precipitates in the polymerization medium. Low molar mass PVAc macroinitiator, prepared by CMRP in scCO2, is then successfully used to initiate the acrylonitrile polymerization. PVAc-b-PAN block copolymer is collected as a free flowing powder at the end of the process although the dispersity of the copolymer increases with the reaction time. Although optimization is required to decrease the dispersity of the polymer formed, this CMRP process opens new perspectives for macromolecular engineering in scCO2 without the utilization of fluorinated comonomers or organic solvents.

  19. Parametric study of Fischer-Tropsch synthesis in supercritical phase carbon dioxide

    Science.gov (United States)

    Gautam, Jitendra

    The results from studies on Fischer Tropsch synthesis wherein syngas was dissolved in CO2 are presented. The syngas generally used was typical of that obtained from coal gasification, i.e. CO:H2 of one. Under these conditions Co-based catalysts without any water gas shift catalyst does not perform well while Fe -- based catalysts have been found to be useful. However, the Fe based catalysts have a propensity towards CO2 selectivity via the primary FT reaction, Boudouard reaction and the water gas shift reaction. The use of CO2 as a solvent was found to suppress the CO2 and CH4 selectivity while enhancing the hydrocarbon selectivity and CO conversion when FT synthesis was conducted using coal derived syngas on Fe-Zn-K catalysts. The effects were found to be significantly pronounced at pressures higher than or equal to 1200 psig. It should be noted that CO2 is supercritical at pressures higher than 1070 psig and 31.4 °C. The effect of CO2 partial pressure, reactor pressure, reaction temperature, catalyst loading and H 2:CO ratio in syngas on the liquid product distribution was evaluated. Some of the notable findings include product tenability by varying temperature and pressure as well as varying the CO2 partial pressure and the syngas composition. Increasing the reactor pressure was found to favor longer chain growth. In addition, it was noted that the ratio between CO2:syngas in the reaction mixture is an important factor in the liquid product distribution. A higher value of the ratio is seen to favor hydrocarbon synthesis, while a lower value of the ratio favors oxygenate production particularly pentanols and butanols. In addition, the data on the once through fractionation of the products utilizing the solubilities in supercritical CO2 and pressure tuning were encouraging. It was found that the products can be easily fractionated into narrow carbon chain length distributions downstream of the reactor by simply reducing the pressures in each collection vessel. It

  20. Determination of Parameters for the Supercritical Extraction of Antioxidant Compounds from Green Propolis Using Carbon Dioxide and Ethanol as Co-Solvent

    Science.gov (United States)

    Barreto, Gabriele de Abreu; Costa, Samantha Serra; Silva, Rejane Pina Dantas; da Silva, Danielle Figuerêdo; Brandão, Hugo Neves; da Rocha, José Luiz Carneiro; Nunes, Silmar Baptista; Umsza-Guez, Marcelo Andres

    2015-01-01

    The aim of this study was to determine the best processing conditions to extract Brazilian green propolis using a supercritical extraction technology. For this purpose, the influence of different parameters was evaluated such as S/F (solvent mass in relation to solute mass), percentage of co-solvent (1 and 2% ethanol), temperature (40 and 50°C) and pressure (250, 350 and 400 bar) using supercritical carbon dioxide. The Global Yield Isotherms (GYIs) were obtained through the evaluation of the yield, and the chemical composition of the extracts was also obtained in relation to the total phenolic compounds, flavonoids, antioxidant activity and 3,5-diprenyl-4-hydroxicinnamic acid (Artepillin C) and acid 4-hydroxycinnamic (p-coumaric acid). The best results were identified at 50°C, 350 bar, 1% ethanol (co-solvent) and S/F of 110. These conditions, a content of 8.93±0.01 and 0.40±0.05 g/100 g of Artepillin C and p-coumaric acid, respectively, were identified indicating the efficiency of the extraction process. Despite of low yield of the process, the extracts obtained had high contents of relevant compounds, proving the viability of the process to obtain green propolis extracts with important biological applications due to the extracts composition. PMID:26252491

  1. Supercritical Carbon Dioxide Extraction of Organic Matter from Petroleum Source Rocks and Its Implications

    Institute of Scientific and Technical Information of China (English)

    沈忠民; 周光甲; 等

    1996-01-01

    Organic matter was experimentally extracted by supercritical fluids(CO2+1% isopropanol)from petroleum source rocks of different thermo-maturities at different buried depths in the same stratigraphic unit in the Dongying Basin.The results show that supercritical fluid extraction(SFE)is more effective than Soxhlet extraction(SE),with higher amounts and greater varieties of hydrocarbons and soluble organic matter becoming extractive.The supercritical CO2 extraction is therefore considered more valuable in evaluation of petroleum source rocks and oil resources,particularly those of immature types.

  2. Optimization of supercritical carbon dioxide extraction of Piper Betel Linn leaves oil and total phenolic content

    Science.gov (United States)

    Aziz, A. H. A.; Yunus, M. A. C.; Arsad, N. H.; Lee, N. Y.; Idham, Z.; Razak, A. Q. A.

    2016-11-01

    Supercritical Carbon Dioxide (SC-CO2) Extraction was applied to extract piper betel linn leaves. The piper betel leaves oil was used antioxidant, anti-diabetic, anticancer and antistroke. The aim of this study was to optimize the conditions of pressure, temperature and flowrate for oil yield and total phenolic content. The operational conditions of SC-CO2 studied were pressure (10, 20, 30 MPa), temperature (40, 60, 80 °C) and flowrate carbon dioxide (4, 6, 8 mL/min). The constant parameters were average particle size and extraction regime, 355pm and 3.5 hours respectively. First order polynomial expression was used to express the extracted oil while second order polynomial expression was used to express the total phenolic content and the both results were satisfactory. The best conditions to maximize the total extraction oil yields and total phenolic content were 30 MPa, 80 °C and 4.42 mL/min leading to 7.32% of oil and 29.72 MPa, 67.53 °C and 7.98 mL/min leading to 845.085 mg GAE/g sample. In terms of optimum condition with high extraction yield and high total phenolic content in the extracts, the best operating conditions were 30 MPa, 78 °C and 8 mL/min with 7.05% yield and 791.709 mg gallic acid equivalent (GAE)/g sample. The most dominant condition for extraction of oil yield and phenolic content were pressure and CO2 flowrate. The results show a good fit to the proposed model and the optimal conditions obtained were within the experimental range with the value of R2 was 96.13% for percentage yield and 98.52% for total phenolic content.

  3. Functional Ginger Extracts from Supercritical Fluid Carbon Dioxide Extraction via In Vitro and In Vivo Assays: Antioxidation, Antimicroorganism, and Mice Xenografts Models

    Directory of Open Access Journals (Sweden)

    Chih-Chen Lee

    2013-01-01

    Full Text Available Supercritical fluid carbon dioxide extraction technology was developed to gain the active components from a Taiwan native plant, Zingiber officinale (ginger. We studied the biological effects of ginger extracts via multiple assays and demonstrated the biofunctions in each platform. Investigations of ginger extracts indicated antioxidative properties in dose-dependant manners on radical scavenging activities, reducing powers and metal chelating powers. We found that ginger extracts processed moderate scavenging values, middle metal chelating levels, and slight ferric reducing powers. The antibacterial susceptibility of ginger extracts on Staphylococcus aureus, Streptococcus sobrinus, S. mutans, and Escherichia coli was determined with the broth microdilution method technique. The ginger extracts had operative antimicroorganism potentials against both Gram-positive and Gram-negative bacteria. We further discovered the strong inhibitions of ginger extracts on lethal carcinogenic melanoma through in vivo xenograft model. To sum up, the data confirmed the possible applications as medical cosmetology agents, pharmaceutical antibiotics, and food supplements.

  4. Functional ginger extracts from supercritical fluid carbon dioxide extraction via in vitro and in vivo assays: antioxidation, antimicroorganism, and mice xenografts models.

    Science.gov (United States)

    Lee, Chih-Chen; Chiou, Li-Yu; Wang, Jheng-Yang; Chou, Sin-You; Lan, John Chi-Wei; Huang, Tsi-Shu; Huang, Kuo-Chuan; Wang, Hui-Min

    2013-01-01

    Supercritical fluid carbon dioxide extraction technology was developed to gain the active components from a Taiwan native plant, Zingiber officinale (ginger). We studied the biological effects of ginger extracts via multiple assays and demonstrated the biofunctions in each platform. Investigations of ginger extracts indicated antioxidative properties in dose-dependant manners on radical scavenging activities, reducing powers and metal chelating powers. We found that ginger extracts processed moderate scavenging values, middle metal chelating levels, and slight ferric reducing powers. The antibacterial susceptibility of ginger extracts on Staphylococcus aureus, Streptococcus sobrinus, S. mutans, and Escherichia coli was determined with the broth microdilution method technique. The ginger extracts had operative antimicroorganism potentials against both Gram-positive and Gram-negative bacteria. We further discovered the strong inhibitions of ginger extracts on lethal carcinogenic melanoma through in vivo xenograft model. To sum up, the data confirmed the possible applications as medical cosmetology agents, pharmaceutical antibiotics, and food supplements.

  5. Quality Attributes of Fresh-Cut Coconut after Supercritical Carbon Dioxide Pasteurization

    Directory of Open Access Journals (Sweden)

    Giovanna Ferrentino

    2013-01-01

    Full Text Available The impact of supercritical CO2 (SC-CO2 process on the quality attributes of fresh-cut coconut has been investigated to establish the acceptability of SC-CO2 treated products by the consumers. Two process conditions, previously identified as optimal to reduce the microbial content of the product, were studied: 12 MPa, 40°C, 30 min and 12 MPa, 45°C, 15 min. The results highlighted that both conditions induced some effects on product attributes. After 30 min of treatment at 12 MPa and 40°C a decrease of lightness (8%, pH (13%, fat content (24%, total phenol content (29%, flavonoid compounds (49%, antioxidant capacity (30% and an increase of dry matter (11% and titratable acidity (51.1% were observed while polyphenol oxidase (PPO exhibited 35% and 98.5% inactivation. Peroxidase enzyme activity increased by 77.8% and 30.4% at 12 MPa, 40°C, 30 min and 12 MPa, 45°C, 15 min, respectively. Sensory evaluations revealed no significant differences in appearance, texture, taste, and aroma of treated fresh-cut coconut compared to the untreated. The study confirms the feasibility of SC-CO2 process for the pasteurization of fresh fruits with a firm structure and opens the door to the possibility of exploiting such a technology at industrial level.

  6. Electrochemistry in supercritical fluids

    Science.gov (United States)

    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

  7. Electrochemistry in supercritical fluids.

    Science.gov (United States)

    Branch, Jack A; Bartlett, Philip N

    2015-12-28

    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.

  8. Improved Sterilization of Sensitive Biomaterials with Supercritical Carbon Dioxide at Low Temperature: e0129205

    National Research Council Canada - National Science Library

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

    2015-01-01

    ... 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...

  9. Wettability of supercritical carbon dioxide/water/quartz systems: simultaneous measurement of contact angle and interfacial tension at reservoir conditions.

    Science.gov (United States)

    Saraji, Soheil; Goual, Lamia; Piri, Mohammad; Plancher, Henry

    2013-06-11

    Injection of carbon dioxide in deep saline aquifers is considered as a method of carbon sequestration. The efficiency of this process is dependent on the fluid-fluid and rock-fluid interactions inside the porous media. For instance, the final storage capacity and total amount of capillary-trapped CO2 inside an aquifer are affected by the interfacial tension between the fluids and the contact angle between the fluids and the rock mineral surface. A thorough study of these parameters and their variations with temperature and pressure will provide a better understanding of the carbon sequestration process and thus improve predictions of the sequestration efficiency. In this study, the controversial concept of wettability alteration of quartz surfaces in the presence of supercritical carbon dioxide (sc-CO2) was investigated. A novel apparatus for measuring interfacial tension and contact angle at high temperatures and pressures based on Axisymmetric Drop Shape Analysis with no-Apex (ADSA-NA) method was developed and validated with a simple system. Densities, interfacial tensions, and dynamic contact angles of CO2/water/quartz systems were determined for a wide range of pressures and temperatures relevant to geological sequestration of CO2 in the subcritical and supercritical states. Image analysis was performed with ADSA-NA method that allows the determination of both interfacial tensions and contact angles with high accuracy. The results show that supercritical CO2 alters the wettability of quartz surface toward less water-wet conditions compared to subcritical CO2. Also we observed an increase in the water advancing contact angles with increasing temperature indicating less water-wet quartz surfaces at higher temperatures.

  10. Supercritical fluid carbon dioxide extraction and liquid chromatographic separation with electrochemical detection of methylmercury from biological samples

    Science.gov (United States)

    Simon, N.S.

    1997-01-01

    Using the coupled methods presented in this paper, methylmercury can be accurately and rapidly extracted from biological samples by modified supercritical fluid carbon dioxide and quantitated using liquid chromatography with reductive electrochemical detection. Supercritical fluid carbon dioxide modified with methanol effectively extracts underivatized methylmercury from certified reference materials Dorm-1 (dogfish muscle) and Dolt-2 (dogfish liver). Calcium chloride and water, with a ratio of 5:2 (by weight), provide the acid environment required for extracting methylmercury from sample matrices. Methylmercury chloride is separated from other organomercury chloride compounds using HPLC. The acidic eluent, containing 0.06 mol L-1 NaCl, insures the presence of methylmercury chloride and facilitates the reduction of mercury on a glassy carbon electrode. If dual glassy carbon electrodes are used, a positive peak is observed at -0.65 to -0.70 V and a negative peak is observed at -0.90V with the organomercury compounds that were tested. The practical detection limit for methylmercury is 5 X 10-8 mol L-1 (1 X 10-12 tool injected) when a 20 ??L injection loop is used.

  11. Genomic insights into growth and survival of supercritical-CO2 tolerant bacterium MIT0214 under conditions associated with geologic carbon dioxide sequestration

    Science.gov (United States)

    Peet, K. C.; Freedman, A. J.; Hernandez, H.; Thompson, J. R.

    2011-12-01

    Carbon capture and storage (CCS) of CO2 has the potential to significantly reduce the emissions of greenhouse gasses associated with fossil fuel combustion. The largest potential for storing captured CO2 in the United Sates is in deep geologic saline formations. Currently, little is known about the effects of CO2 storage on biologically active microbial communities found in the deep earth biosphere. Therefore, to investigate how deep earth microbial communities will be affected by the storage of CO2 we have enriched for a microbial consortium from the saline formation waters of the Frio 2 project site (Texas Gulf Coast) that is capable of growth in nutrient media under a supercritical CO2 headspace (Hernandez, et al). The cultivation of actively growing cells in an environment containing scCO2 is unexpected based on previous experimental evidence of microbial sterilization attributed to the acidic, desiccating, and solvent-like properties of scCO2. We have isolated strain MIT0214 from this supercritical CO2 based enrichment and have sequenced its genome using the Illumina platform followed by de novo assembly of reads and targeted Sanger sequencing to reduce gaps in the draft assembly. The genome of strain MIT0214 is approximately 5,551,062 base pairs with 35% GC-content and is most similar to nonpathogenic Bacillus cereus strain ATCC 14597. Annotation of the draft assembly of the MIT0214 genome by the Rapid Annotation using Subsystem Technology (RAST) server revealed 5538 coding sequences where 4145 of the coding sequences were assigned putative functions. These functions were enriched in cell wall and capsule formation, phage/prophage and plasmids, gene regulation and signaling, and nitrogen and sulfur metabolism relative to the genome of the most closely-related surface-isolated B. cereus reference (ATCC 14597) and in total 773,416 bp of the MIT0214 genome content was distinct from the B. cereus reference. Notably, this set of distinct sequences were most

  12. Carbon Capture: A Technology Assessment

    Science.gov (United States)

    2013-10-21

    time. The absence of a significant market for the novel technologies put them at a further disadvantage . This is similar to the situation for CO2...the overall CCS process applied to a power plant or other industrial process. The CO2 produced from carbon in the fossil fuels or biomass feedstock...Air or Oxygen Fossil Fuels; Biomass USEFUL PRODUCTS (e.g., electricity, fuels, chemicals, hydrogen) CO2 CO2 Capture & Compress CO2 Transport CO2

  13. NERI Quarterly Progress Report -- April 1 - June 30, 2005 -- Development of a Supercritical Carbon Dioxide Brayton Cycle: Improving PBR Efficiency and Testing Material Compatibility

    Energy Technology Data Exchange (ETDEWEB)

    Chang Oh

    2005-07-01

    The objective of this research is to improve a helium Brayton cycle and to develop a supercritical carbon dioxide Brayton cycle for the Pebble Bed Reactor (PBR) that can also be applied to the Fast Gas-Cooled Reactor (FGR) and the Very-High-Temperature Gas-Cooled Reactor (VHTR). The proposed supercritical carbon dioxide Brayton cycle will be used to improve the PBR, FGR, and VHTR net plant efficiency. Another objective of this research is to test materials to be used in the power conversion side at supercritical carbon dioxide conditions. Generally, the optimized Brayton cycle and balance of plant (BOP) to be developed from this study can be applied to Generation-IV reactor concepts. Particularly, we are interested in VHTR because it has a good chance of being built in the near future.

  14. DETERMINATION OF ROCK-BREAKING PERFORMANCE OF HIGH-PRESSURE SUPERCRITICAL CARBON DIOXIDE JET

    Institute of Scientific and Technical Information of China (English)

    DU Yu-kun; WANG Rui-he; NI Hong-jian; LI Mu-kun; SONG Wei-qiang; SONG Hui-fang

    2012-01-01

    In this study,a well-designcd cxperimental setup is used to determine the rock-breaking performance of a high-pressure supercritical carbon dioxide (SC-CO2) jet.Its rock-breaking performance is first compared with that of a high-pressure water jet under the same operation conditions.The effects of five major factors that affect the rock-breaking performance of the high-pressure SC-CO2 jet,i.e.,the nozzle diameter,the standoff distance,the jet pressure,the rock compressive strength and the jet temperature are experimentally determined.The experimental results indicate that the rock-breaking performance of the SC-CO2 jet is significantly improved over the high-pressure water jet.It is also found that the rock-breaking performance of the SC-CO2 jet is improved with the increase of the nozzle diameter or the standoff distance,until the nozzle diameter or the standoff distance reaches a certain critical value and after that it begins to deteriorate.The rock-breaking performance of the SC-CO2 jet improves monotonically with the increase of the jet pressure,while it shows a monotonic deterioration with the increase of the rock compressive strength.In addition,it is found that,under the same working conditions,the SC-CO2 jet can always provide a better rock-breaking performance than the subcritical liquid CO2 jet.

  15. Iridium-catalyzed enantioselective hydrogenation of imines in supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Kainz, S.; Brinkmann, A.; Leitner, W.; Pfaltz, A.

    1999-07-14

    Supercritical carbon dioxide (scCO{sub 2}) was shown to be a reaction medium with unique properties for highly efficient iridium-catalyzed enantioselective hydrogenation of prochiral imines. Cationic iridium(I) complexes with chiral phosphinodihydrooxazoles, modified with perfluoroalkyl groups in the ligand or in the anion, were synthesized and tested in the hydrogenation of N-(1-phenylethylidene)aniline. Both the side chains and the lipophilic anions increased the solubility, but the choice of the anion also had a dramatic effect on the enantioselectivity with tetrakis-3,5-bis(trifluoromethyl)phenylborate (BARF) leading to the highest asymmetric induction. (R)-N-phenyl-1-phenylethylamine was formed quantitatively within 1 h in scCO{sub 2}[d(CO{sub 2}) = 0.75 g mL{sup {minus}1}] at 40 C and a H{sub 2} pressure of 30 bar with enantiomeric excesses of up to 81% using 0.078 mol % catalyst. The use of scCO{sub 2} instead of conventional solvents such as CH{sub 2}Cl{sub 2} allowed the catalyst loading to be lowered significantly owing to a change in the rate profile of the reaction. the homogeneous nature of the catalytically active species under the reaction conditions was demonstrated and was found to depend strongly on the composition of the reaction mixture and especially on the presence of the substrate. Utilizing the selective extractive properties of scCO{sub 2}, the product could be readily separated from the catalyst, which could be recycled several times without significant loss of activity and enantioselectivity. High-pressure FT-IR and NMR investigations revealed that the reactivity of the products to form the corresponding carbamic acids plays an important role for the application of this new methodology.

  16. Supercritical carbon dioxide-processed resorbable polymer nanocomposites for bone graft substitute applications

    Science.gov (United States)

    Baker, Kevin C.

    Numerous clinical situations necessitate the use of bone graft materials to enhance bone formation. While autologous and allogenic materials are considered the gold standards in the setting of fracture healing and spine fusion, their disadvantages, which include donor site morbidity and finite supply have stimulated research and development of novel bone graft substitute materials. Among the most promising candidate materials are resorbable polymers, composed of lactic and/or glycolic acid. While the characteristics of these materials, such as predictable degradation kinetics and biocompatibility, make them an excellent choice for bone graft substitute applications, they lack mechanical strength when synthesized with the requisite porous morphology. As such, porous resorbable polymers are often reinforced with filler materials. In the presented work, we describe the use of supercritical carbon dioxide (scCO2) processing to create porous resorbable polymeric constructs reinforced by nanostructured, organically modified Montmorillonite clay (nanoclay). scCO2 processing simultaneously disperses the nanoclay throughout the polymeric matrix, while imparting a porous morphology to the construct conducive to facilitating cellular infiltration and neoangiogenesis, which are necessary components of bone growth. With the addition of as little as 2.5wt% of nanoclay, the compressive strength of the constructs nearly doubles putting them on par with human cortico-cancellous bone. Rheological measurements indicate that the dominant mode of reinforcement of the nanocomposite constructs is the restriction of polymer chain mobility. This restriction is a function of the positive interaction between polymer chains and the nanoclay. In vivo inflammation studies indicate biocompatibility of the constructs. Ectopic osteogenesis assays have determined that the scCO2-processed nanocomposites are capable of supporting growth-factor induced bone formation. scCO 2-processed resorbable

  17. Study of mass transfer in supercritical carbon dioxide (SCCO2) using optical methods

    Science.gov (United States)

    Hu, M.; Benning, R.; Ertunç, Ö.; Delgado, A.; Nercissian, V.; Berger, M.

    2017-06-01

    The purpose of this work is to design and develop a type of experiment setup that would enable the direct observation of steady diffusion process in situ. Two different optical methods - shadowgraph and shearing interferometry - were used for the first time to visualise and quantitatively analyse the diffusion around a droplet of organic substance in supercritical carbon dioxide (SCCO2) as well as in its direct vicinity. We constructed and tested a cylindrical high-pressure chamber and an experiment system with a high speed camera. The solute/solvent combination of DL-α-tocopherol/SCCO2 was applied using shadowgraph. The diffusion coefficients at temperatures of 40o C, 50o C and 60o C and pressures between 75 bar and 90 bar were calculated based on the displacement of the droplet contour in the captured images. The shearing interferometry with a Wollaston-prism was then applied not only for the combination of DL-α-tocopherol/SCCO2, but also for other substances in SCCO2, for example for a type of rose oil and lubricant oil as well as for acetone, benzene, toluene and naphthalene. The changes of the refractive index gradient were directly measured and evaluated with the interferograms; afterwards changes of the density gradients and the diffusion coefficients were determined. We propose then a multivariate regression model to capture the relationship between the diffusion coefficient, the pressure and the temperature. To minimize the influence of gravity-driven convections in the solvent during diffusion, the experiments were also carried out under microgravity condition, i.e. in two parabolic flight campaigns.

  18. Fractionation of Whey Protein Isolate with Supercritical Carbon Dioxide—Process Modeling and Cost Estimation

    Directory of Open Access Journals (Sweden)

    Andrew McAloon

    2011-12-01

    Full Text Available An economical and environmentally friendly whey protein fractionation process was developed using supercritical carbon dioxide (sCO2 as an acid to produce enriched fractions of α-lactalbumin (α-LA and β-lactoglobulin (β-LG from a commercial whey protein isolate (WPI containing 20% α-LA and 55% β-LG, through selective precipitation of α-LA. Pilot-scale experiments were performed around the optimal parameter range (T = 60 to 65 °C, P = 8 to 31 MPa, C = 5 to 15% (w/w WPI to quantify the recovery rates of the individual proteins and the compositions of both fractions as a function of processing conditions. Mass balances were calculated in a process flow-sheet to design a large-scale, semi-continuous process model using SuperproDesigner® software. Total startup and production costs were estimated as a function of processing parameters, product yield and purity. Temperature, T, pressure, P, and concentration, C, showed conflicting effects on equipment costs and the individual precipitation rates of the two proteins, affecting the quantity, quality, and production cost of the fractions considerably. The highest α-LA purity, 61%, with 80% α-LA recovery in the solid fraction, was obtained at T = 60 °C, C = 5% WPI, P = 8.3 MPa, with a production cost of $8.65 per kilogram of WPI treated. The most profitable conditions resulted in 57%-pure α-LA, with 71% α-LA recovery in the solid fraction and 89% β-LG recovery in the soluble fraction, and production cost of $5.43 per kilogram of WPI treated at T = 62 °C, C = 10% WPI and P = 5.5 MPa. The two fractions are ready-to-use, new food ingredients with a pH of 6.7 and contain no residual acid or chemical contaminants.

  19. Anxiolytic activity of a supercritical carbon dioxide extract of Souroubea sympetala (Marcgraviaceae).

    Science.gov (United States)

    Mullally, Martha; Kramp, Kari; Cayer, Chris; Saleem, Ammar; Ahmed, Fida; McRae, Calum; Baker, John; Goulah, Andrew; Otorola, Marco; Sanchez, Pablo; Garcia, Mario; Poveda, Luis; Merali, Zul; Durst, Tony; Trudeau, Vance L; Arnason, John Thor

    2011-02-01

    The purpose of this work was to develop an extraction technique to yield a betulinic acid-(BA) enriched extract of the traditional anti-anxiety plant Souroubea sympetala Gilg (Marcgraviaceae). Five extraction techniques were compared: supercritical carbon dioxide extraction (SCE), conventional solvent extraction with ethyl acetate (EtOAc), accelerated solvent extraction (ASE), ultrasonic assisted extraction (UAE) and soxhlet extraction (Sox). The EtOAc and SCE extraction methods resulted in BA-enriched extracts, with BA concentrations of 6.78 ± 0.2 and 5.54 ± 0.2 mg/g extract, respectively, as determined by HPLC-APCI-MS. The bioactivity of the BA-enriched extracts was compared in the elevated plus maze (EPM), a validated rodent anxiety behaviour assay. Rats orally administered a 75 mg/kg dose of SCE extract exhibited anxiolysis as compared with vehicle controls, with a 50% increase in the percent time spent in the open arms, a 73% increase in unprotected head dips and a 42% decrease in percent time spent in the closed arms. No significant differences were observed between the SCE and EtOAc extracts for these measures, but the animals dosed with SCE extract had significantly more unprotected head dips than those dosed with the EtOAc extract. The SCE extract demonstrated a dose-response in the EPM, with a trend toward decreased anxiety at 25 mg/kg, and significant anxiolysis was only observed at 75 mg/kg dose. This study demonstrates that SCE can be used to generate a betulinic acid-enriched extract with significant anxiolysis in vivo. Further, the study provides a scientific basis for the ethnobotanical use of this traditional medicine and a promising lead for a natural health product to treat anxiety.

  20. Carbon nanotubes-supported palladium nanoparticles for the Suzuki reaction in supercritical carbon dioxide:A facile method for the synthesis of tetrasubstituted olefins

    Institute of Scientific and Technical Information of China (English)

    ZHOU Lei; ZHANG WeiDe; JIANG HuanFeng

    2008-01-01

    A facile and efficient method for the synthesis of tetrasubstituted olefins in supercritical carbon dioxide was developed by using carbon nanotubes-supported palladium nanoparticles (Pd/CNTs) as the cata-lyst. Compared with common Pd/C, Pd/CNTs could more effectively catalyze the reaction of di-bromo-substituted olefins with boronic acids, affording the corresponding tetrasubstituted olefins with moderate to good yields. This environmentally benign route with an easy-to-handle catalyst provides an appealing alternative to the currently available methods.

  1. Carbon nanotubes-supported palladium nanoparticles for the Suzuki reaction in supercritical carbon dioxide: A facile method for the synthesis of tetrasubstituted olefins

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A facile and efficient method for the synthesis of tetrasubstituted olefins in supercritical carbon dioxide was developed by using carbon nanotubes-supported palladium nanoparticles (Pd/CNTs) as the catalyst. Compared with common Pd/C, Pd/CNTs could more effectively catalyze the reaction of dibromo-substituted olefins with boronic acids, affording the corresponding tetrasubstituted olefins with moderate to good yields. This environmentally benign route with an easy-to-handle catalyst provides an appealing alternative to the currently available methods.

  2. Optimized process for recovery of glass- and carbon fibers with retained mechanical properties by means of near- and supercritical fluids

    DEFF Research Database (Denmark)

    Sokoli, Hülya U.; Beauson, Justine; Simonsen, Morten E.

    2017-01-01

    on the resin degradation efficiency and the quality of the recovered glass and carbon fibers. Supercritical acetone at 260 ºC, 60 bar and a c/s ratio up to 2.1 g/mL could achieve nearly complete degradation of the resin. The glass fibers were recovered with up to 89% retained tensile strength compared...... to the virgin glass fibers. The use of near-critical water reduced the tensile strength of the glass fibers by up to 65%, whereas the carbon fibers were recovered with retained tensile strength compared to the virgin carbon fibers using water or acetone.......Degradation of hybrid fiber composites using near-critical water or supercritical acetone has been investigated in this study. Process parameters such as temperature (T= 260-300 ºC), pressure (p = 60-300 bar) and composite/solvent (c/s = 0.29-2.1 g/mL) ratio were varied to determine the effect...

  3. Evaluation of supercritical fluid technology as preparative technique of benzocaine-cyclodextrin complexes--comparison with conventional methods.

    Science.gov (United States)

    Al-Marzouqi, Ali H; Jobe, Baboucarr; Dowaidar, Ali; Maestrelli, Francesca; Mura, Paola

    2007-01-17

    The objective of this study was to investigate the effect of the preparation method on the physico-chemical properties of complexes prepared between beta-cyclodextrin (beta-Cyd) and benzocaine (BZC). In particular, the effectiveness of a new technique based on supercritical carbon dioxide (SC CO(2)) for preparing solid drug-cyclodextrin complexes was investigated and compared to other more conventional methods such as kneading (KN), co-evaporation (COE), co-grinding (GR) and sealed-heating (S.H.). Effects of temperature, pressure and exposure time on the properties of complexes prepared by SC CO(2) technology were also studied. The different systems were characterized by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), powder X-ray diffractometry (PXRD) and dissolution test according to the dispersed amount method. The co-grinding (GR) method resulted in amorphous products while other methods led to crystalline or partially amorphous products depending on both the method and its experimental conditions. SC CO(2) method revealed to be an effective technique for preparing solid systems between beta-cyclodextrin and benzocaine, avoiding the use of organic solvents (and problems of their complete removal) and allowing an easy scale-up of the process. As for the influence of the experimental conditions in promoting the solid-state drug-carrier interaction when using the SC CO(2) method, temperature seemed to play the major role, whereas pressure and exposure times had more limited effects. Dissolution tests confirmed a limited but favourable effect in increasing the exposure time, while indicated a possible interaction effect between temperature and pressure in influencing the dissolution performance of the final product. The best product obtained by the SC CO(2) method showed dissolution properties similar to those of the co-ground product and only slightly lower than the system obtained by sealed-heating, which was the most

  4. Adsorption equilibrium of citric acid from supercritical carbon dioxide/ethanol on cyano column

    Institute of Scientific and Technical Information of China (English)

    Huisheng L; Guoqing Wang; Minhua Zhang; Zhongfeng Geng; Miao Yang; Yanpeng Sun

    2015-01-01

    Supercritical adsorption equilibrium has a significant role in defining supercritical adsorption behavior. In this paper, the adsorption equilibrium of citric acid from supercritical CO2/ethanol on a cyano column was systemat-ical y investigated with the elution by characteristic point method. Equilibrium loading was obtained at 313.15 K and 321.15 K with supercritical CO2/ethanol densities varying from 0.7068 g·cm−3 to 0.8019 g·cm−3. The exper-imental results showed that the adsorption capacity of citric acid decreased with increasing temperature and in-creasing density of the supercritical CO2/ethanol mobile phase. The adsorption equilibrium data were fitted wel by the Quadratic Hill isotherm model and the isotherms showed anti-Langmuir behavior. The monolayer satura-tion adsorption capacity of citric acid is in the range of 44.54 mg·cm−3 to 64.66 mg·cm−3 with an average value of 56.86 mg·cm−3.

  5. Fixed Bed Adsorption of Drugs on Silica Aerogel from Supercritical Carbon Dioxide Solutions

    Directory of Open Access Journals (Sweden)

    Giuseppe Caputo

    2013-01-01

    Full Text Available Supercritical adsorption coupled with the high adsorption capacity of silica aerogel allows the preparation of a new kind of delivery systems of poor water soluble drugs. In order to overcome drawbacks of conventional techniques where the use of liquid solvents can cause the fracture of aerogel porous structure, in this work a new adsorption process of drugs from a supercritical mixture is proposed. Adsorption takes place from a fluid solution of the drug in supercritical CO2 and ethanol as cosolvent. A fixed bed adsorption plant has been developed to allow fast mixing of fluid phase and effective contact in the adsorption column. The use of ethanol as cosolvent allows to overcome the limitation of supercritical adsorption due to low solubility of many drugs in supercritical CO2. Adsorption isotherms were measured for one-model substance, nimesulide, at 40°C, and breakthrough curve was experimentally obtained. The drug loading of the drug into silica aerogel was up to 9 wt%. The drug composite was characterized using scanning electron microscopy, and release kinetics of the adsorbed drug were also evaluated by in vitro dissolution tests. The dissolution of nimesulide from loaded aerogel is much faster than dissolution of crystalline nimesulide. Around 80% of nimesulide dissolves from the aerogel within 6 minutes, whereas dissolving 80% of the crystalline drug takes about 90 min.

  6. The effect of oxidation treatment with supercritical water/hydrogen peroxide system on intersurface performance for polyacrylonitrile-based carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Linghui; Fan, Dapeng; Zhang, Chunhua; Jiang, Zaixing [School of Chemical Engineering and Technology, Harbin Institute of Technology, P.O. Box 410, Harbin 150001 (China); Huang, Yudong, E-mail: ydhuang.hit1@yahoo.com.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, P.O. Box 410, Harbin 150001 (China)

    2013-05-15

    In order to improve the interfacial properties between carbon fibers and epoxy matrix, supercritical water and hydrogen peroxide were used as oxidation medium for the oxidation treatment for carbon fibers. Analysis results of X-ray photoelectron spectroscopy suggest that the oxygen content on the carbon fibers’ surfaces increases by these oxidation treatments. Scanning electron microscope and atomic force microscopy images indicate that the surface appearance of oxidized carbon fibers obviously changed. The maximal interlaminar shear strength and interface shear strength of carbon fiber/epoxy resin composite in which the fibers were treated by the supercritical water and hydrogen peroxide systems reaches 70.46 MPa and 106.66 MPa, increases by 13.4% and 29.6% respectively compared with untreated carbon fibers.

  7. The effect of oxidation treatment with supercritical water/hydrogen peroxide system on intersurface performance for polyacrylonitrile-based carbon fibers

    Science.gov (United States)

    Meng, Linghui; Fan, Dapeng; Zhang, Chunhua; Jiang, Zaixing; Huang, Yudong

    2013-05-01

    In order to improve the interfacial properties between carbon fibers and epoxy matrix, supercritical water and hydrogen peroxide were used as oxidation medium for the oxidation treatment for carbon fibers. Analysis results of X-ray photoelectron spectroscopy suggest that the oxygen content on the carbon fibers' surfaces increases by these oxidation treatments. Scanning electron microscope and atomic force microscopy images indicate that the surface appearance of oxidized carbon fibers obviously changed. The maximal interlaminar shear strength and interface shear strength of carbon fiber/epoxy resin composite in which the fibers were treated by the supercritical water and hydrogen peroxide systems reaches 70.46 MPa and 106.66 MPa, increases by 13.4% and 29.6% respectively compared with untreated carbon fibers.

  8. Flightweight Carbon Nanotube Magnet Technology

    Science.gov (United States)

    Chapman, J. N.; Schmidt, H. J.; Ruoff, R. S.; Chandrasekhar, V.; Dikin, D. A.; Litchford, R. J.

    2003-01-01

    Virtually all plasma-based systems for advanced airborne/spaceborne propulsion and power depend upon the future availability of flightweight magnet technology. Unfortunately, current technology for resistive and superconducting magnets yields system weights that tend to counteract the performance advantages normally associated with advanced plasma-based concepts. The ongoing nanotechnology revolution and the continuing development of carbon nanotubes (CNT), however, may ultimately relieve this limitation in the near future. Projections based on recent research indicate that CNTs may achieve current densities at least three orders of magnitude larger than known superconductors and mechanical strength two orders of magnitude larger than steel. In fact, some published work suggests that CNTs are superconductors. Such attributes imply a dramatic increase in magnet performance-to-weight ratio and offer real hope for the construction of true flightweight magnets. This Technical Publication reviews the technology status of CNTs with respect to potential magnet applications and discusses potential techniques for using CNT wires and ropes as a winding material and as an integral component of the containment structure. The technology shortfalls are identified and a research and technology strategy is described that addresses the following major issues: (1) Investigation and verification of mechanical and electrical properties, (2) development of tools for manipulation and fabrication on the nanoscale, (3) continuum/molecular dynamics analysis of nanotube behavior when exposed to practical bending and twisting loads, and (4) exploration of innovative magnet fabrication techniques that exploit the natural attributes of CNTs.

  9. Enzyme-assisted supercritical fluid extraction: an alternative and green technology for non-extractable polyphenols.

    Science.gov (United States)

    Mushtaq, Muhammad; Sultana, Bushra; Akram, Sumia; Anwar, Farooq; Adnan, Ahmad; Rizvi, Syed S H

    2017-03-22

    This contribution proposes an enzyme-assisted eco-friendly process for the extraction of non-extractable polyphenols (NEPPs) from black tea leftover (BTLO), an underutilized tea waste. BTLO hydrolyzed with various enzyme formulations was extracted using supercritical carbon dioxide and ethanol as co-solvent (SC-CO2 + EtOH). A conventional solvent extraction (CSE) was performed using EtOH + H2O (80:20, v/v) for comparison purposes. The results revealed that hydrolysis of BTLO with 2.9% (w/w) kemzyme at 45 °C and pH 5.4 for 98 min improved the liberation of NEPPs offering 5-fold higher extract yield (g/100 g) as compared with non-treated BTLO. In vitro antioxidant evaluation and LC-MS characterization of extracts revealed the presence of phenolic acids (mainly caffeic and para-coumaric acid) of high antioxidant value. Scanning electron micrograph of the hydrolyzed BTLO samples indicated noteworthy changes in the ultrastructure of BTLO. Moreover, polyphenol extracts obtained by SC-CO2 + EtOH extraction were found to be cleaner and richer in polyphenols as compared to CSE. The devised enzyme-assisted SC-CO2 + EtOH extraction process in the present work can be explored as an effective biotechnological mean for the optimal recovery of antioxidant polyphenols. Graphical abstract Enzymatic pretreatment can effectively liberate non-extractable polyphenols (NEPPs) while hydrolyzing the cellulosic and hemicellulosic framework of black tea left overs (BTLO).

  10. Mineral Carbonation in Wet Supercritical CO2: An in situ High-Pressure Magic Angle Spinning Nuclear Magnetic Resonance Study

    Science.gov (United States)

    Turcu, R. V.; Hoyt, D. H.; Sears, J. A.; Rosso, K. M.; Felmy, A. R.; Hu, J. Z.

    2011-12-01

    Understanding the mechanisms and kinetics of mineral carbonation reactions relevant to sequestering carbon dioxide as a supercritical fluid (scCO2) in geologic formations is crucial for accurately predicting long-term storage risks. In situ probes that provide molecular-level information at geologically relevant temperatures and pressures are highly desirable and challenging to develop. Magic angle spinning nuclear magnetic resonance (MAS NMR) is a powerful tool for obtaining detailed molecular structure and dynamics information of a system regardless whether the system is in a solid, a liquid, a gaseous, a supercritical state, or a mixture thereof. However, MAS NMR under scCO2 conditions has never been realized due to the tremendous technical difficulties of achieving and maintaining high pressure within a fast spinning MAS sample rotor. In this work, we report development of a unique high pressure MAS NMR capability capable of handling fluid pressure exceeding 170 bars and temperatures up to 80°C, and its application to mineral carbonation in scCO2 under geologically relevant temperatures and pressures. Mineral carbonation reactions of the magnesium silicate mineral forsterite and the magnesium hydroxide brucite reacted with scCO2 (up to 170 bar) and containing variable content of H2O (at, below, and above saturation in scCO2) were investigated at 50 to 70°C. In situ 13C MAS NMR spectra show peaks corresponding to the reactants, intermediates, and the magnesium carbonation products in a single spectrum. For example, Figure 1 shows the reaction dynamics, i.e., the formation and conversion of reaction intermediates, i.e., HCO3- and nesquehonite, to magnesite as a function of time at 70°C. This capability offers a significant advantage over traditional ex situ 13C MAS experiments on similar systems, where, for example, CO2 and HCO3- are not directly observable.

  11. Corrosion in Supercritical carbon Dioxide: Materials, Environmental Purity, Surface Treatments, and Flow Issues

    Energy Technology Data Exchange (ETDEWEB)

    Sridharan, Kumar; Anderson, Mark

    2013-12-10

    The supercritical CO{sub 2} Brayton cycle is gaining importance for power conversion in the Generation IV fast reactor system because of its high conversion efficiencies. When used in conjunction with a sodium fast reactor, the supercritical CO{sub 2} cycle offers additional safety advantages by eliminating potential sodium-water interactions that may occur in a steam cycle. In power conversion systems for Generation IV fast reactors, supercritical CO{sub 2} temperatures could be in the range of 30°C to 650°C, depending on the specific component in the system. Materials corrosion primarily at high temperatures will be an important issue. Therefore, the corrosion performance limits for materials at various temperatures must be established. The proposed research will have four objectives centered on addressing corrosion issues in a high-temperature supercritical CO{sub 2} environment: Task 1: Evaluation of corrosion performance of candidate alloys in high-purity supercritical CO{sub 2}: The following alloys will be tested: Ferritic-martensitic Steels NF616 and HCM12A, austenitic alloys Incoloy 800H and 347 stainless steel, and two advanced concept alloys, AFA (alumina forming austenitic) steel and MA754. Supercritical CO{sub 2} testing will be performed at 450°C, 550°C, and 650°C at a pressure of 20 MPa, in a test facility that is already in place at the proposing university. High purity CO{sub 2} (99.9998%) will be used for these tests. Task 2: Investigation of the effects of CO, H{sub 2}O, and O{sub 2} impurities in supercritical CO{sub 2} on corrosion: Impurities that will inevitably present in the CO{sub 2} will play a critical role in dictating the extent of corrosion and corrosion mechanisms. These effects must be understood to identify the level of CO{sub 2} chemistry control needed to maintain sufficient levels of purity to manage corrosion. The individual effects of important impurities CO, H{sub 2}O, and O{sub 2} will be investigated by adding them

  12. Moisture content and particle size of dehydrated egg yolk affect lipid and cholesterol extraction using supercritical carbon dioxide.

    Science.gov (United States)

    Froning, G W; Wehling, R L; Cuppett, S; Niemann, L

    1998-11-01

    Egg yolk was spray-dried under conditions to produce a small particle size powder and a large particle size powder. Particle size was determined using a Nikon Optiophot microscope. Spray-dried egg yolk was also adjusted to various moisture levels as follows: control (2 to 4% moisture), 7% moisture, and 12% moisture. Supercritical carbon dioxide extraction (SCE) of each of these moisture treatments at 45 C/306 atm using 30 g CO2/g of sample was completed. For the particle size study, 45 g CO2/g of sample at 45 C/306 atm was utilized. Particle size exhibited a significant effect on cholesterol and lipids extracted using SCE. As moisture content of dried egg yolk increased to 7%, there was a significant increase in lipids extracted using supercritical carbon dioxide. Moisture content had no significant effect on cholesterol extraction. After extracting SCE higher moisture spray-dried egg yolk, sponge cake volume was significantly reduced compared to that of the control. The reduced sponge cake volume may be due to protein denaturation.

  13. Panax ginseng Fraction F3 Extracted by Supercritical Carbon Dioxide Protects against Oxidative Stress in ARPE-19 Cells.

    Science.gov (United States)

    Yang, Chao-Chin; Chen, Chiu-Yuan; Wu, Chun-Chi; Koo, Malcolm; Yu, Zer-Ran; Wang, Be-Jen

    2016-10-13

    In our previous work, the ethanolic extract of Panax ginseng C. A. Meyer was successively partitioned using supercritical carbon dioxide at pressures in series to yield residue (R), F1, F2, and F3 fractions. Among them, F3 contained the highest deglycosylated ginsenosides and exerted the strongest antioxidant and anti-inflammatory activities. The aim of this study was to investigate the protective effects of P. ginseng fractions against cellular oxidative stress induced by hydrogen peroxide (H₂O₂). Viability of adult retinal pigment epithelium-19 (ARPE-19) cells was examined after treatments of different concentrations of fractions followed by exposure to H₂O₂. Oxidative levels (malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), and reactive oxygen species (ROS)) and levels of activity of antioxidant enzymes were assessed. Results showed that F3 could dose-dependently protected ARPE-19 cells against oxidative injury induced by H₂O₂. F3 at a level of 1 mg/mL could restore the cell death induced by H₂O₂ of up to 60% and could alleviate the increase in cellular oxidation (MDA, 8-OHdG, and ROS) induced by H₂O₂. Moreover, F3 could restore the activities of antioxidant enzymes suppressed by H₂O₂. In conclusion, F3 obtained using supercritical carbon dioxide fractionation could significantly increase the antioxidant capacity of P. ginseng extract. The antioxidant capacity was highly correlated with the concentration of F3.

  14. Micronization processes by supercritical fluid technologies: a short review on process design (2008-2012 - doi: 10.4025/actascitechnol.v35i4.18819

    Directory of Open Access Journals (Sweden)

    Jose Vladimir de Oliveira

    2013-10-01

    Full Text Available Several micronization processes based on supercritical fluids have been developed. These processes can be classified according to the role of the supercritical fluid in the process: solvent, solute or co-solvent, and anti-solvent. Application of supercritical fluids as alternative to traditional micronization methods and the growing demand of the industrial sector for new technologies motivated this review. In this context, the objective of this work was to present the operating principles of the micronization process by means of supercritical fluids and the effects of the main process variables on particles characteristics. The review continues with an update of current experimental data presented in the literature in the period from 2008 to 2012.   

  15. Characterization of Ketoprofen/Methyl-β-Cyclodextrin Complexes Prepared Using Supercritical Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Mauro Banchero

    2013-01-01

    Full Text Available Complexes of methyl-β-cyclodextrin and ketoprofen, a crystalline anti-inflammatory drug with poor water solubility, have been prepared for the first time in the presence of supercritical CO2 at 40°C and 20 MPa. The supercritical treatment allows these pharmaceutical formulations to be prepared without the use of any auxiliary agents or organic solvents. The treated samples were characterized through differential scanning calorimetry, X-ray diffractometry, and the Fourier transform infrared spectroscopy to exclude the presence of crystalline drug and check the formation of the complexes. The increase of the drug dissolution rate was investigated performing in vitro release tests in aqueous solutions. The results showed that the supercritical treatment can be an efficient method to obtain inclusion complexes with enhanced release kinetics. The operating methods of the release tests, that is, the “tablet method” or the “dispersed amount method,” affected both the dissolution rate and its dependence on the drug amount in the samples. On the contrary, the variation of the pH of the dissolution medium did not show any effect on the release rate of the supercritical complexes.

  16. Carbon nanotubes: A promising catalyst support material for supercritical water gasification of biomass waste

    NARCIS (Netherlands)

    Vlieger, de D.J.M.; Thakur, D.B.; Lefferts, L.; Seshan, K.

    2012-01-01

    Supercritical water (SCW) as a reaction medium is especially promising for the production of renewable chemicals from biomass. Stability issues of catalyst support materials in SCW are a major setback for these reactions and hinder the further development and industrial exploitation of this techniqu

  17. Supercritical carbon dioxide (CO2) assisted preparation of hydrogen-bonded interpolymer complexes

    CSIR Research Space (South Africa)

    Labuschagne, Philip W

    2010-10-01

    Full Text Available The use of supercritical CO2 as medium in polymer processing eliminates many of disadvantages associated with other means of processing, i.e. high temperatures or toxic solvents. The “soft” processing conditions make CO2 specifically suitable...

  18. Development and characterization of ordered, highly oriented, composite laminates using supercritical carbon dioxide

    Science.gov (United States)

    Caskey, Terrence Colin

    This thesis describes the development and subsequent characterization of a series of oriented, highly ordered laminated composite materials. These laminated composite materials all possess order over varying length-scales from angstrom level molecular chain orientation to macro-scale order in woven fabrics. In each case, supercritical carbon dioxide (SC CO2) is used as a unique reaction medium and processing aid allowing for the development of structures not previously attainable with standard techniques. The goal of this research is two-fold, the first goal involves the proof of concept, exhibiting the ability to attain novel composite structures using unique SC CO2 chemistries and processes. The second goal of this research is aimed at developing a thorough understanding of how these unique structures and morphologies translate into an overall mechanical response for the material. This work will be divided into three distinct but interrelated projects. The first project involves the development of a unique SC CO2 assisted solvent welding technique. This technique is then applied towards the fabrication of a quasi-isotropic laminate comprised of a series of solvent-welded uniaxially-oriented linear low density polyethylene films (LLDPE). The geometry of this laminate is designed to exploit the improved strength and rigidity of uniaxially oriented LLDPE films while suppressing undesireable transverse properties. The second project to be addressed in this project involves the development of fiber-reinforced composites with unique nano-scale morphologies. The long-range order in these composites has profound effects on both the individual fiber properties as well as the overall composite properties. The final project of interest in this work involves the development of intercalated silicate nano-composites with high clay content. In order to achieve the desired morphologies it is necessary to create polymer/clay nano-composites with very high clay content

  19. Supercritical water

    CERN Document Server

    Marcus, Yizhak

    2012-01-01

    Discover the many new and emerging applications of supercritical water as a green solvent Drawing from thousands of original research articles, this book reviews and summarizes what is currently known about the properties and uses of supercritical water. In particular, it focuses on new and emerging applications of supercritical water as a green solvent, including the catalytic conversion of biomass into fuels and the oxidation of hazardous materials. Supercritical Water begins with an introduction that defines supercritical fluids in general. It then defines supercritical wa

  20. Nonthermal inactivation of Escherichia coli K12 in buffered peptone water using a pilot-plant scale supercritical carbon dioxide system with gas-liquid porous metal contractor

    Science.gov (United States)

    This study evaluated the effectiveness of a supercritical carbon dioxide (SCCO2) system, with a gas-liquid CO2 contactor, for reducing Escherichia coli K12 in diluted buffered peptone water. 0.1% (w/v) buffered peptone water inoculated with E. coli K12 was processed using the SCCO2 system at CO2 con...

  1. Nonthermal processing of orange juice using a pilot-plant scale supercritical carbon dioxide system with a gas-liquid metal contactor

    Science.gov (United States)

    To evaluate the effect of pilot-plant scale, non-thermal supercritical carbon dioxide (SCCO2) processing on the safety and the quality of orange juice (OJ), SCCO2 processed juice was compared with untreated fresh juice and equivalently thermal processed juice in terms of lethality. SCCO2 processing ...

  2. Fractionation of whey protein isolate with supercritical carbon dioxide to produce enriched alpha-lactalbumin and beta-lactoglobulin food ingredients

    Science.gov (United States)

    A potentially economical and environmentally friendly whey protein fractionation process was developed using supercritical carbon dioxide (SCO2) as an acid to produce enriched fractions of alpha-lactalbumin (a-LA) and beta-lactoglobulin (b-LG) from whey protein isolate. To prepare the fractions, so...

  3. Design and evaluation of a high temperature/pressure supercritical carbon dioxide direct tubular receiver for concentrating solar power applications

    Science.gov (United States)

    Ortega, Jesus Daniel

    This work focuses on the development of a solar power thermal receiver for a supercritical-carbon dioxide (sCO2), Brayton power-cycle to produce ~1 MWe. Closed-loop sCO2 Brayton cycles are being evaluated in combination with concentrating solar power to provide higher thermal-to-electric conversion efficiencies relative to conventional steam Rankine cycles. High temperatures (923--973 K) and pressures (20--25 MPa) are required in the solar receiver to achieve thermal efficiencies of ~50%, making concentrating solar power (CSP) technologies a competitive alternative to current power generation methods. In this study, the CSP receiver is required to achieve an outlet temperature of 923 K at 25 MPa or 973 K at 20 MPa to meet the operating needs. To obtain compatible receiver tube material, an extensive material review was performed based the ASME Boiler and Pressure Vessel Code, ASME B31.1 and ASME B313.3 codes respectively. Subsequently, a thermal-structural model was developed using a commercial computational fluid (CFD) dynamics and structural mechanics software for designing and analyzing the tubular receiver that could provide the heat input for a ~2 MWth plant. These results were used to perform an analytical cumulative damage creep-fatigue analysis to estimate the work-life of the tubes. In sequence, an optical-thermal-fluid model was developed to evaluate the resulting thermal efficiency of the tubular receiver from the NSTTF heliostat field. The ray-tracing tool SolTrace was used to obtain the heat-flux distribution on the surfaces of the receiver. The K-ω SST turbulence model and P-1 radiation model used in Fluent were coupled with SolTrace to provide the heat flux distribution on the receiver surface. The creep-fatigue analysis displays the damage accumulated due to the cycling and the permanent deformation of the tubes. Nonetheless, they are able to support the required lifetime. The receiver surface temperatures were found to be within the safe

  4. Nanotechnology and supercritical fluids | Hamidreza | Journal of ...

    African Journals Online (AJOL)

    Several techniques have been proposed to produce nanomaterials using ... of the supercritical based techniques applied to the production of nanoparticles materials. Keywords: Supercritical fluids; Nanoparticles; SCF technology; RESS; SAS.

  5. Comparative study on the quality of oil extracted from two tucumã varieties using supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    Bárbara Elizabeth Teixeira COSTA

    2016-01-01

    Full Text Available Abstract The vast Amazon region has considerable territorial peculiarities and plant species diversity, sometimes from the same botanical family, which can exhibit significant differences in physicochemical properties. From this diversity, two species stand out – Amazonas tucumã (Astrocaryum aculeatum Meyer and Pará tucumã (Astrocaryum vulgare Mart.. The research focus is to analyze, comparatively, these oleaginous fruits, their similarities, particularities and potentials regarding the oil quality extracted from two tucumã varieties from the states of Amazonas and Pará, obtained using supercritical carbon dioxide, under different extraction parameters. The results demonstrate the biometric particularities of each species, highlighting the Amazon fruit, which also showed higher oil yield using supercritical CO2 extraction. The fatty acid quality and profile aspects of the oils show their unsaturated predominance, considering carotenoid content and how the extraction temperature can influence the nutritional quality of the oils. The statistical analyses indicated that the Amazon tucumã oil is superior to the Pará tucumã oil. However, in terms of added value both oils have potential applications in various industrial segments.

  6. Extraction of semivolatile organic compounds from high-efficiency particulate air (HEPA) filters by supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Schilling, J.B.

    1997-09-01

    Supercritical fluid extraction (SFE) using unmodified carbon dioxide has been explored as an alternative method for the extraction of semivolatile organic compounds from high-efficiency particulate air (HEPA) filters. HEPA filters provide the final stage of containment on many exhaust systems in US Department of Energy (DOE) facilities by preventing the escape of chemical and radioactive materials entrained in the exhausted air. The efficiency of the filters is tested by the manufacturer and DOE using dioctylphthalate (DOP), a substance regulated by the US Environmental Protection Agency under the Resource Conservation and Recovery Act. Therefore, the filters must be analyzed for semivolatile organics before disposal. Ninety-eight acid, base, and neutral semivolatile organics were spiked onto blank HEPA material and extracted using SFE, Soxhlet, automated Soxhlet, and sonication techniques. The SFE conditions were optimized using a Dionex SFE-703 instrument. Average recoveries for the 98 semivolatile compounds are 82.7% for Soxhlet, 74.0% for sonication, 70.2% for SFE, and 62.9% for Soxtec. Supercritical fluid extraction reduces the extraction solvent volume to 10--15 mL, a factor of 20--30 less than Soxhlet and more than 5 times less than Soxtec and sonication. Extraction times of 30--45 min are used compared to 16--18 h for Soxhlet extraction.

  7. Numerical simulation of the solvate structures of acetylsalicylic acid in supercritical carbon dioxide containing polar co-solvents

    Science.gov (United States)

    Petrenko, V. E.; Antipova, M. L.; Gurina, D. L.; Odintsova, E. G.; Kumeev, R. S.; Golubev, V. A.

    2016-07-01

    Hydrogen-bonded complexes of acetylsalicylic acid with polar co-solvents in supercritical carbon dioxide, modified by methanol, ethanol, and acetone of 0.03 mole fraction concentration, are studied by numerical methods of classical molecular dynamics simulation and quantum chemical calculations. The structure, energy of formation, and lifetime of hydrogen-bonded complexes are determined, along with their temperature dependences (from 318 to 388 K at constant density of 0.7 g cm-3). It is shown that the hydrogen bonds between acetylsalicylic acid and methanol are most stable at 318 K and are characterized by the highest value of absolute energy. At higher supercritical temperatures, however, the longest lifetime is observed for acetylsalicylic acid-ethanol complexes. These results correlate with the known literature experimental data showing that the maximum solubility of acetylsalicylic acid at density values close to those considered in this work and at temperatures of 318 and 328 K is achieved when using methanol and ethanol as co-solvents, respectively.

  8. Molecular dynamics simulation of diffusion coefficients and structural properties of some alkylbenzenes in supercritical carbon dioxide at infinite dilution.

    Science.gov (United States)

    Wang, Jinyang; Zhong, Haimin; Feng, Huajie; Qiu, Wenda; Chen, Liuping

    2014-03-14

    The binary infinite dilute diffusion coefficients, D₁₂(∞), of some alkylbenzenes (Ph-C(n), from Ph-H to Ph-C12) from 313 K to 333 K at 15 MPa in supercritical carbon dioxide (scCO2) have been studied by molecular dynamics (MD) simulation. The MD values agree well with the experimental ones, which indicate MD simulation technique is a powerful way to predict and obtain diffusion coefficients of solutes in supercritical fluids. Besides, the local structures of Ph-C(n)/CO2 fluids are further investigated by calculating radial distribution functions and coordination numbers. It qualitatively convinces that the first solvation shell of Ph-C(n) in scCO2 is significantly influenced by the structure of Ph-C(n) solute. Meanwhile, the mean end-to-end distance, the mean radius of gyration and dihedral angle distribution are calculated to gain an insight into the structural properties of Ph-C(n) in scCO2. The abnormal trends of radial distribution functions and coordination numbers can be reasonably explained in term of molecular flexibility. Moreover, the computed results of dihedral angle clarify that flexibility of long-chain Ph-C(n) is the result of internal rotation of C-C single bond (σ(c-c)) in alkyl chain. It is interesting that compared with n-alkane, because of the existence of benzene ring, the flexibility of alkyl chain in Ph-C(n) with same carbon atom number is significantly reduced, as a result, the carbon chain dependence of diffusion behaviors for long-chain n-alkane (n ≥ 5) and long-chain Ph-C(n) (n ≥ 4) in scCO2 are different.

  9. Gasification Mechanism of Carbon with Supercritical Water at Very High Pressures: Effects on H2 Production.

    Science.gov (United States)

    Martin-Sanchez, Nicolas; Salvador, Francisco; Sanchez-Montero, M Jesus; Izquierdo, Carmen

    2014-08-07

    The scarce data concerning the gasification of carbonaceous solids with supercritical water (SCW) suggest the great potential of this method to produce a valuable green fuel such as H2. However, the extraordinary properties of SCW have not been properly applied to H2 production because the mechanism that governs gasification under these conditions remains unclear. Here, we present a study in which this reaction is explored within the largest pressure range ever assayed in this field, from 1 to 1000 bar. The amplitude of the experimental conditions investigated highlights the various pathways that govern gasification with steam and SCW. Under supercritical conditions, the clusters formed around the superficial groups of the solid reduce the energetic requirements for gasification and generate CO2 as a primary product of the reaction. Consequently, gasification with SCW is significantly faster than that using steam, and the produced gases are richer and more appropriate to obtain pure H2.

  10. Structure of phosphate fluorosurfactant based reverse micelles in supercritical carbon dioxide

    OpenAIRE

    Senapati, S; Keiper, J. S.; de Simone, J. M.; Wignall, G. D.; Melnichenko, Y. B.; Frielinghaus, H; Berkowitz, M. L.

    2002-01-01

    The existence of microemulsions in the system composed of phosphate-based fluorosurfactant, water, and supercritical CO2 is demonstrated by small-angle neutron scattering experiments. A computer simulation study performed on a reverse micelle created in this system shows that the micelle remains stable over a 4 ns time period of the simulation. While the data obtained from the experiments provide information about the size of the reverse micelle, the data obtained from the simulations provide...

  11. Literature survey of heat transfer and hydraulic resistance of water, carbon dioxide, helium and other fluids at supercritical and near-critical pressures

    Energy Technology Data Exchange (ETDEWEB)

    Pioro, I.L.; Duffey, R.B

    2003-04-01

    This survey consists of 430 references, including 269 Russian publications and 161 Western publications devoted to the problems of heat transfer and hydraulic resistance of a fluid at near-critical and supercritical pressures. The objective of the literature survey is to compile and summarize findings in the area of heat transfer and hydraulic resistance at supercritical pressures for various fluids for the last fifty years published in the open Russian and Western literature. The analysis of the publications showed that the majority of the papers were devoted to the heat transfer of fluids at near-critical and supercritical pressures flowing inside a circular tube. Three major working fluids are involved: water, carbon dioxide, and helium. The main objective of these studies was the development and design of supercritical steam generators for power stations (utilizing water as a working fluid) in the 1950s, 1960s, and 1970s. Carbon dioxide was usually used as the modeling fluid due to lower values of the critical parameters. Helium, and sometimes carbon dioxide, were considered as possible working fluids in some special designs of nuclear reactors. (author)

  12. Thermodynamics and Phase Behavior of Miscible Polymer Blends in the Presence of Supercritical Carbon Dioxide

    Science.gov (United States)

    Young, Nicholas Philip

    The design of environmentally-benign polymer processing techniques is an area of growing interest, motivated by the desire to reduce the emission of volatile organic compounds. Recently, supercritical carbon dioxide (scCO 2) has gained traction as a viable candidate to process polymers both as a solvent and diluent. The focus of this work was to elucidate the nature of the interactions between scCO2 and polymers in order to provide rational insight into the molecular interactions which result in the unexpected mixing thermodynamics in one such system. The work also provides insight into the nature of pairwise thermodynamic interactions in multicomponent polymer-polymer-diluent blends, and the effect of these interactions on the phase behavior of the mixture. In order to quantify the strength of interactions in the multicomponent system, the binary mixtures were characterized individually in addition to the ternary blend. Quantitative analysis of was made tractable through the use of a model miscible polymer blend containing styrene-acrylonitrile copolymer (SAN) and poly(methyl methacrylate) (dPMMA), a mixture which has been considered for a variety of practical applications. In the case of both individual polymers, scCO2 is known to behave as a diluent, wherein the extent of polymer swelling depends on both temperature and pressure. The solubility of scCO 2 in each polymer as a function of temperature and pressure was characterized elsewhere. The SAN-dPMMA blend clearly exhibited lower critical solution temperature behavior, forming homogeneous mixtures at low temperatures and phase separating at elevated temperature. These measurements allowed the determination of the Flory-Huggins interaction parameter chi23 for SAN (species 2) and dPMMA (species 3) as a function of temperature at ambient pressure, in the absence of scCO2 (species 1). Characterization of the phase behavior of the multicomponent (ternary) mixture was also carried out by SANS. An in situ SANS

  13. 超临界CO2技术在PP中应用进展%Application Progress of Supercritical CO2 Technology for Polypropylene

    Institute of Scientific and Technical Information of China (English)

    李峰; 康鹏; 金滟

    2012-01-01

    The application of the supercritical CO2 technology to polypropylene in grafting modification, crystallizing modification, microporous foamed material, processing and composite material at home and abroad is reviewed. And the application prospect of the supercritical CO2 technology is predicted.%综述了超临界CO2(SC-CO2)技术在聚丙烯(PP)接枝改性、结晶改性、PP微发泡材料、加工和复合材料等方面应用,并展望了SC-CO2技术在PP中的应用前景.

  14. Extraction of volatile oil from aromatic plants with supercritical carbon dioxide: experiments and modeling.

    Science.gov (United States)

    Coelho, Jose P; Cristino, Ana F; Matos, Patrícia G; Rauter, Amélia P; Nobre, Beatriz P; Mendes, Rui L; Barroso, João G; Mainar, Ana; Urieta, Jose S; Fareleira, João M N A; Sovová, Helena; Palavra, António F

    2012-09-05

    An overview of the studies carried out in our laboratories on supercritical fluid extraction (SFE) of volatile oils from seven aromatic plants: pennyroyal (Mentha pulegium L.), fennel seeds (Foeniculum vulgare Mill.), coriander (Coriandrum sativum L.), savory (Satureja fruticosa Béguinot), winter savory (Satureja montana L.), cotton lavender (Santolina chamaecyparisus) and thyme (Thymus vulgaris), is presented. A flow apparatus with a 1 L extractor and two 0.27 L separators was built to perform studies at temperatures ranging from 298 to 353 K and pressures up to 30.0 MPa. The best compromise between yield and composition compared with hydrodistillation (HD) was achieved selecting the optimum experimental conditions of extraction and fractionation. The major differences between HD and SFE oils is the presence of a small percentage of cuticular waxes and the relative amount of thymoquinone, an oxygenated monoterpene with important biological properties, which is present in the oils from thyme and winter savory. On the other hand, the modeling of our data on supercritical extraction of volatile oil from pennyroyal is discussed using Sovová's models. These models have been applied successfully to the other volatile oil extractions. Furthermore, other experimental studies involving supercritical CO(2) carried out in our laboratories are also mentioned.

  15. Extraction of Volatile Oil from Aromatic Plants with Supercritical Carbon Dioxide: Experiments and Modeling

    Directory of Open Access Journals (Sweden)

    Helena Sovová

    2012-09-01

    Full Text Available An overview of the studies carried out in our laboratories on supercritical fluid extraction (SFE of volatile oils from seven aromatic plants: pennyroyal (Mentha pulegium L., fennel seeds (Foeniculum vulgare Mill., coriander (Coriandrum sativum L., savory (Satureja fruticosa Béguinot, winter savory (Satureja montana L., cotton lavender (Santolina chamaecyparisus and thyme (Thymus vulgaris, is presented. A flow apparatus with a 1 L extractor and two 0.27 L separators was built to perform studies at temperatures ranging from 298 to 353 K and pressures up to 30.0 MPa. The best compromise between yield and composition compared with hydrodistillation (HD was achieved selecting the optimum experimental conditions of extraction and fractionation. The major differences between HD and SFE oils is the presence of a small percentage of cuticular waxes and the relative amount of thymoquinone, an oxygenated monoterpene with important biological properties, which is present in the oils from thyme and winter savory. On the other hand, the modeling of our data on supercritical extraction of volatile oil from pennyroyal is discussed using Sovová’s models. These models have been applied successfully to the other volatile oil extractions. Furthermore, other experimental studies involving supercritical CO2 carried out in our laboratories are also mentioned.

  16. Corrosion of Structural Materials for Advanced Supercritical Carbon- Dioxide Brayton Cycle

    Energy Technology Data Exchange (ETDEWEB)

    Sridharan, Kumar [Univ. of Wisconsin, Madison, WI (United States)

    2017-05-13

    The supercritical carbon-dioxide (referred to as SC-CO2 hereon) Brayton cycle is being considered for power conversion systems for a number of nuclear reactor concepts, including the sodium fast reactor (SFR), fluoride saltcooled high temperature reactor (FHR), and high temperature gas reactor (HTGR), and several types of small modular reactors (SMR). The SC-CO2 direct cycle gas fast reactor has also been recently proposed. The SC-CO2 Brayton cycle (discussed in Chapter 1) provides higher efficiencies compared to the Rankine steam cycle due to less compression work stemming from higher SC-CO2 densities, and allows for smaller components size, fewer components, and simpler cycle layout. For example, in the case of a SFR using a SC-CO2 Brayton cycle instead of a steam cycle would also eliminate the possibility of sodium-water interactions. The SC-CO2 cycle has a higher efficiency than the helium Brayton cycle, with the additional advantage of being able to operate at lower temperatures and higher pressures. In general, the SC-CO2 Brayton cycle is well-suited for any type of nuclear reactor (including SMR) with core outlet temperature above ~ 500°C in either direct or indirect versions. In all the above applications, materials corrosion in high temperature SC-CO2 is an important consideration, given their expected lifetimes of 20 years or longer. Our discussions with National Laboratories and private industry early on in this project indicated materials corrosion to be one of the significant gaps in the implementation of SC-CO2 Brayton cycle. Corrosion can lead to a loss of effective load-bearing wall thickness of a component and can potentially lead to the generation of oxide particulate debris which can lead to three-body wear in turbomachinery components. Another environmental degradation effect that is rather unique to CO2 environment is the possibility

  17. A vibrational spectroscopic study of structure evolution of water dissolved in supercritical carbon dioxide under isobaric heating.

    Science.gov (United States)

    Oparin, R; Tassaing, T; Danten, Y; Besnard, M

    2004-06-08

    A combination of Raman scattering spectroscopy and infrared absorption was applied to investigate the structural evolution of water dissolved in supercritical carbon dioxide under isobaric heating (T=40-340 degrees C, P=250 bar). Quantitative analysis of experimental spectra allowed us to determine that at relatively moderate temperatures water dissolved in CO(2)-rich phase exists only under monomeric form (solitary water surrounding by CO(2) molecules), but hydrogen-bonded species, namely, dimers, begin to appear upon heating. At the same time, the ratio of dimers to monomers concentration increases with further temperature increase and at temperatures close to the temperature of total miscibility of the mixture (T=366 degrees C, P=250 bar), water dimers only are present in the CO(2)-rich phase. (c) 2004 American Institute of Physics.

  18. New polyimide-polyoxometalate nanocomposite materials with nanoporous structure and ultra-low dielectric constant, formed in supercritical carbon dioxide

    Science.gov (United States)

    Keshtov, Mukhamed; Said-Galiev, Ernest; Kochurov, Vitaliy; Khokhlov, Alexei

    2012-07-01

    Vinyltrimethoxysilane interaction with K8(SiW11O39) obtained polyoxometalate (Bu4N)4[SiW11O39{(CH2 = CH-Si)2O}](SiW11-CH = CH2). Synthesized two new fluorinated aromatic polyimide in two stages with a dielectric constant (k) in the range 2.70-2.75. On the basis of poly(amic acids) and a mixture of thermal imidization polyoxometalate obtained polyimide/polyoxometalate composite film. It was found that with increasing polyoxometalate in a mixture of 0 to 20 wt% the dielectric constant decreases from 2,75 to 1,70. Nanoporous materials with ultra-low dielectric constant in the range 1.31-1.64 in combination with high thermal (T10% = 536-570°C in N2) and mechanical characteristics using supercritical carbon dioxide have been developed on the basis of the obtained polyimide/polyoxometalate composite films.

  19. Comparison between the essential oil and supercritical Carbon Dioxide extraction of Mentha Piperita L. cultivated in Iran

    Directory of Open Access Journals (Sweden)

    Aghel N

    2002-08-01

    Full Text Available The chemical compositions of the essential oils and the volatile concentrate of Mentha piperita L. (Labiatae obtained by supercritical carbon dioxide extraction (SFE at 35°C and 100 atm were compared using GC/MS. Whereas twenty four components were identified in the essential oil, only seven compounds, including the main compounds of the peppermint oil were isolated by the SFE. The percent of major components of the oil and the extract were: Menthol (31.53 and 48.39, Menthone (23.37 and 26.68 and Isomenthone (11.11 and 6.58, respectively. From these results it may concluded that the SFE method supply a selective essential oil extract.

  20. Application of response surface methodology to optimise supercritical carbon dioxide extraction of essential oil from Cyperus rotundus Linn.

    Science.gov (United States)

    Wang, Hongwu; Liu, Yanqing; Wei, Shoulian; Yan, Zijun

    2012-05-01

    Supercritical fluid extraction with carbon dioxide (SC-CO2 extraction) was performed to isolate essential oils from the rhizomes of Cyperus rotundus Linn. Effects of temperature, pressure, extraction time, and CO2 flow rate on the yield of essential oils were investigated by response surface methodology (RSM). The oil yield was represented by a second-order polynomial model using central composite rotatable design (CCRD). The oil yield increased significantly with pressure (poil yield from the response surface equation was predicted to be 1.82% using an extraction temperature of 37.6°C, pressure of 294.4bar, extraction time of 119.8 min, and CO2 flow rate of 20.9L/h.

  1. In situ generation of biodegradable poly(ρ-dioxanone) micro-particles by polymerization in supercritical carbon dioxide

    Institute of Scientific and Technical Information of China (English)

    Tian Qiang Wang; Xiu Li Zhao; Jian Yuan Hao

    2011-01-01

    Ring-opening suspension polymerization of p-dioxanone (PDO) in supercritical carbon dioxide (scCO2) was investigated in the presence of poly(caprolactone)-perfluropolyether-poly(caprolactone) (PCL-PFPE-PCL). The molecular weight, yield and particle morphology of poly(p-dioxanone) (PPDO) were studied. The stabilizer was effective to stabilize the ring-opening polymerization (ROP) of PDO in SCCO2, leading to the formation of resorbable microparticles in a "one pot" procedure. The mean size of PPDO microparticles obtained from suspension polymerizations was sensitive to the rate of agitation and the stabilizer concentration. The method to generate PPDO microparticles has overcome its unprocessable drawback with common organic solvents and provided new product form for biomedical applications.

  2. Solubility prediction of disperse dyes in supercritical carbon dioxide and ethanol as co-solvent using neural network

    Institute of Scientific and Technical Information of China (English)

    Ahmad KhazaiePoul; M Soleimani; S Salahi

    2016-01-01

    Nowadays artificial neural networks (ANNs) with strong ability have been applied widely for prediction of non-linear phenomenon. In this work an optimized ANN with 7 inputs that consist of temperature, pressure, critical temperature, critical pressure, density, molecular weight and acentric factor has been used for solubility predic-tion of three disperse dyes in supercritical carbon dioxide (SC-CO2) and ethanol as co-solvent. It was shown how a multi-layer perceptron network can be trained to represent the solubility of disperse dyes in SC-CO2. Numeric Sensitivity Analysis and Garson equation were utilized to find out the degree of effectiveness of different input variables on the efficiency of the proposed model. Results showed that our proposed ANN model has correlation coefficient, Nash–Sutcliffe model efficiency coefficient and discrepancy ratio about 0.998, 0.992, and 1.053 respectively.

  3. The influence of dissolved H2O content in supercritical carbon dioxide to the inclusion complexes formation of ketoprofen/β-cyclodextrin

    Science.gov (United States)

    Goenawan, Joshua; Trisanti, P. N.; Sumarno

    2015-12-01

    This work studies the relation between dissolved H2O content in supercritical carbon dioxide (SC-CO2) with the formation of ketoprofen (KP)/β-cyclodextrin(CD) inclusion complexes. The process involves a physical mixture of these two compounds into contact with the supercritical carbon dioxide which had been previously saturated with H2O over a certain duration. The pressure used for saturation process is 130 bar and saturation temperature was ranged between 30 °C to 50 °C. The inclusion process was achieved by keeping it for 2 hours at 160 bar and 200 bar with inclusion temperature of 50 °C. The results enable us to suggest explanations for the inclusion formation. The inclusion complexes can be formed by contacting the dissolved H2O in SC-CO2 to the physical mixture of KP and CD. An increase in the temperature of saturation process resulted in an increase of dissolved H2O content in the supercritical carbon dioxide. The increasing levels of this water soluble resulted an increase in the inclusion complexes that has been formed. The formation of inclusion complexes includes the water molecules enhancing the emptying of the CD cavities and being replaced by KP, towards a more stable energy state. The drug release used for analyzing the dissolution rate of the KP/CD complexes. The results vary from 79,85% to 99,98% after 45 minutes which is above the rate that has been assigned by Farmakope Indonesia at 70% dissolution rate for KP. The use of SC-CO2 offers a new methods for increasing the rate of dissolution of drugs that are hydrophobic such as KP. CO2 used as a supercritical fluid because of its relatively low cost, easily obtainable supercritical conditions, and lack of toxicity. The material samples were characterized by DSC and Spectrophotometer UV-vis technique.

  4. Supercritical Technologies for the Valorization of Wine Industry By-Products

    OpenAIRE

    Duba, Kurabachew Simon

    2015-01-01

    This study aim at the valorization of wine industry by products; particularly on the extraction and characterization of grape seeds oil using supercritical CO2 (SC-CO2) and polyphenols from grape skins and defatted grape seeds using subcritical water (SW) and then, modeling of the kinetics of extractions and process economic analysis. The overall objective of the work is to develop recovery strategies for wine-making wastes in order to reduce their environmental impact and to valorize them in...

  5. Supercritical Combustion of Liquid Oxygen and Hydrocarbon for Staged-Combustion Cycle Engine Technology Development

    Science.gov (United States)

    2009-06-30

    Flows," J. Comput. Phys. 101, 104(1992). P.K. Kundu and I.M. Cohen, Fluid Mechanics , 2nd ed. (San Diego, California, 2001). S. Wang and V. Yang...various underlying mechanisms dictating the fluid atomization and energy-transfer behaviors; and 3) to identify and prioritize key injector design...present numerical analysis is able to capture many unique mechanisms dictating supercritical fluid injection and mixing dynamics, including thermodynamic

  6. ENGINEERING BULLETIN: SUPERCRITICAL WATER OXIDATION

    Science.gov (United States)

    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...

  7. Supercritical carbon dioxide as an innovative reaction medium for selective oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Loeker, F.; Leitner, W. [Max-Planck-Institut fuer Kohlenforschung, Muelheim an der Ruhr (Germany)

    1998-12-31

    Although the catalytic efficiency of all catalytic oxidation processes studied in scCO{sub 2} up to now is far from being satisfactory, the principle possibility to carry out such reactions in this medium is clearly evident. Future research in our group will be directed towards the development of homogeneous and heterogeneous catalysts that are adopted to the special requirements of both the oxidation process and the supercritical reaction medium. Preliminary results from these studies regarding the epoxidation of olefins with molecular oxygen as oxidant will be presented on the conference poster. (orig.)

  8. Carotenoids, Fatty Acid Composition and Heat Stability of Supercritical Carbon Dioxide-Extracted-Oleoresins

    OpenAIRE

    Antonella Leone; Lucia Leo; Cristiano Longo

    2012-01-01

    The risk of chronic diseases has been shown to be inversely related to tomato intake and the lycopene levels in serum and tissue. Cis-isomers represent approximately 50%–80% of serum lycopene, while dietary lycopene maintains the isomeric ratio present in the plant sources with about 95% of all-trans-lycopene. Supercritical CO2 extraction (S-CO2) has been extensively developed to extract lycopene from tomato and tomato processing wastes, for food or pharmaceutical industries, also by using ad...

  9. Development of a Sterile Amniotic Membrane Tissue Graft Using Supercritical Carbon Dioxide

    Science.gov (United States)

    2015-03-04

    manipulated with small changes in temperature and pressure, thus making supercritical fluids applicable to many industrial and labo- ratory processes.12–14 Of...Regenerative Medicine, U.S. Army Institute of Surgical Research, JBSA Fort Sam Houston, Texas. TISSUE ENGINEERING: Part C Volume 21, Number 7, 2015 ª Mary...Regenerative Medicine U.S. Army Institute of Surgical Research JBSA Fort Sam Houston, TX 78234 E-mail: robert.j.christy12.civ@mail.mil Received: May 27, 2014

  10. Preliminary evaluation of polymer-based drug composite microparticle production by coacervate desolvation with supercritical carbon dioxide.

    Science.gov (United States)

    Yasuji, Takehiko; Haslam, John; Kajiyama, Atsushi; McIntosh, Michelle P; Rajewski, Roger A

    2006-03-01

    Drug/polymer particles incorporating phenytoin in polyvinylpyrrolidone (PVP) were prepared by desolvation of coacervates sprayed through an ultrasonic converging-diverging nozzle into supercritical (SC) carbon dioxide. The mean diameter of the particles produced and the crystallinity of phenytoin in the drug/polymer particles were evaluated with an Aerosizer DSP Particle Size Analyzer and powder X-ray diffraction, respectively. The drug release properties from the composite particles were evaluated using the USP 24 Method 2 rotational paddle method with UV detection. Spraying PVP in ethanol solution into SC carbon dioxide did not produce particles. However, a PVP coacervate in a mixture of ethanol and hexanes had lower viscosity than the solution, and spraying the coacervate into SC carbon dioxide through an ultrasonic converging-diverging nozzle produced micron sized particles. The use of a coacervate containing phenytoin and PVP likely led to increased interaction between drug and polymer and the composite particles contained amorphous phenytoin. The drug content in the composite particles approached theoretical values. The drug release rates from the composite particles produced from the coacervate were faster than those from particles produced by conventional SC methods and complete release was observed.

  11. [Technology of extraction of essential oil from leaves of Vitex negundo L. var. heterophylla (Franch.) Rehd. by supercritical CO2 apparatus].

    Science.gov (United States)

    Xie, Jianchun; Sun, Baoguo; Zheng, Fuping; Yu, Min

    2005-12-01

    By the designation of mono-factor experiments and orthogonal multifactor experiments, influences of extraction temperature, extraction pressure, CO2 flow rate and extraction times on the yield of oil from the leaves of Vitex negundo L. var. heterophylla (Franch.) Rehd. in the supercritical CO2 extraction process were investigated. The obtained optimal extraction technology was: the extraction pressure: 22 MPa; the extraction temperature: 45 degrees C; the CO2 flow rate: 25 L/h and the extraction time: 3h. The oil yield on the above supercritical CO2 extraction conditions was 3.22%.

  12. A high-pressure atomic force microscope for imaging in supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Lea, A. S.; Higgins, S. R.; Knauss, K. G.; Rosso, K. M.

    2011-01-01

    A high-pressure atomic force microscope(AFM) that enables in situ, atomic scale measurements of topography of solid surfaces in contact with supercritical CO2 (scCO2) fluids has been developed. This apparatus overcomes the pressure limitations of the hydrothermal AFM and is designed to handle pressures up to 100 atm at temperatures up to ~350 K. A standard optically-based cantilever deflection detection system was chosen. When imaging in compressible supercritical fluids such as scCO2, precise control of pressure and temperature in the fluid cell is the primary technical challenge. Noise levels and imaging resolution depend on minimization of fluid density fluctuations that change the fluidrefractive index and hence the laser path. We demonstrate with our apparatus in situ atomic scale imaging of a calcite (CaCO3) mineral surface in scCO2; both single, monatomic steps and dynamic processes occurring on the (101¯4) surface are presented. Finally, this new AFM provides unprecedented in situ access to interfacial phenomena at solid–fluid interfaces under pressure.

  13. Thermoeconomic Analysis and Optimization of a New Combined Supercritical Carbon Dioxide Recompression Brayton/Kalina Cycle

    Directory of Open Access Journals (Sweden)

    S. Mohammad S. Mahmoudi

    2016-10-01

    Full Text Available A new combined supercritical CO2 recompression Brayton/Kalina cycle (SCRB/KC is proposed. In the proposed system, waste heat from a supercritical CO2 recompression Brayton cycle (SCRBC is recovered by a Kalina cycle (KC to generate additional electrical power. The performances of the two cycles are simulated and compared using mass, energy and exergy balances of the overall systems and their components. Using the SPECO (Specific Exergy Costing approach and employing selected cost balance equations for the components of each system, the total product unit costs of the cycles are obtained. Parametric studies are performed to investigate the effects on the SCRB/KC and SCRBC thermodynamic and thermoeconomic performances of key decision parameters. In addition, considering the exergy efficiency and total product unit cost as criteria, optimization is performed for the SCRBC and SCRB/KC using Engineering Equation Solver software. The results indicate that the maximum exergy efficiency of the SCRB/KC is higher than that of the SCRBC by up to 10%, and that the minimum total product unit cost of the SCRB/KC is lower than that of the SCRBC by up to 4.9%.

  14. 超临界CO2法制备褪黑素脂质体的工艺优化%Technology optimization of melatonin liposome using supercritical CO2

    Institute of Scientific and Technical Information of China (English)

    赵少杰; 叶盛英; 欧春凤; 郑森鸿

    2014-01-01

    Melatonin is an indole hormone produced by the pineal gland of mammals and humans. It can improve sleep, immune regulation, anti-oxidant and free radical scavenging, anti-tumor, lower blood pressure, regulate heart rate, protection of cardiovascular cells, kidneys, liver and other effects. Melatonin nutrient application in the food industry is greatly limited due to low solubility in water. When melatonin is made into liposomes, it’s solubility in polar solvent is increased. However, the current preparing methods of melatonin liposomes are complicated, result in the low entrapment rate, high cost, and use too much organic solvent. From 1970s, supercritical fluids technology has been used in liposomal preparation because of its friendliness, nontoxicity to the environment and its solvent-free liposomes and industrial-scale of liposome production. Phospholipid, cholesterol and melatonin can be solvated by supercritical carbon dioxide concurrently with a certain proportion of ethanol under higher pressure. The liposomes can be obtained when the pressure is reduced to release CO2. The homogeneous super-critical solution is expanded and simultaneously mixed with the aqueous phase to yield liposomes encapsulating the lipid soluble drugs under the lower pressure. The experiment was conducted to enhance the bioavailability of melatonin by improving entrapment rate in this study. The response surface methodology was used to optimize the technical conditions of supercritical carbon dioxide method for the preparation of melatonin liposome. The entrapment rate of melatonin liposome as a major index was optimized based on the ethanol concentration, supercritical temperature and time by response surface methodology using single factor experiments. The applicability of the quadratic-multinomial-mathematical model developed based on the response surface methodology was verified. The results indicated that the highest entrapment rate of melatonin liposome was reached to 83

  15. Possible use of the carbohydrates present in tomato pomace and in byproducts of the supercritical carbon dioxide lycopene extraction process as biomass for bioethanol production.

    Science.gov (United States)

    Lenucci, Marcello S; Durante, Miriana; Anna, Montefusco; Dalessandro, Giuseppe; Piro, Gabriella

    2013-04-17

    This study provides information about the carbohydrate present in tomato pomace (skins, seeds, and vascular tissues) as well as in the byproducts of the lycopene supercritical carbon dioxide extraction (SC-CO₂) such as tomato serum and exhausted matrix and reports their conversion into bioethanol. The pomace, constituting approximately 4% of the tomato fruit fresh weight, and the SC-CO₂-exhausted matrix were enzyme saccharified with 0.1% Driselase leading to sugar yields of ~383 and ~301 mg/g dw, respectively. Aliquots of the hydrolysates and of the serum (80% tomato sauce fw) were fermented by Saccharomyces cerevisiae . The bioethanol produced from each waste was usually >50% of the calculated theoretical amount, with the exception of the exhausted matrix hydolysate, where a sugar concentration >52.8 g/L inhibited the fermentation process. Furthermore, no differences in the chemical solubility of cell wall polysaccharides were evidenced between the SC-CO₂-lycopene extracted and unextracted matrices. The deduced glycosyl linkage composition and the calculated amount of cell wall polysaccharides remained similar in both matrices, indicating that the SC-CO₂ extraction technology does not affect their structure. Therefore, tomato wastes may well be considered as potential alternatives and low-cost feedstock for bioethanol production.

  16. Environmentally benign formation of polymeric microspheres by rapid expansion of supercritical carbon dioxide solution with a nonsolvent.

    Science.gov (United States)

    Matsuyama, K; Mishima, K; Umemoto, H; Yamaguchi, S

    2001-10-15

    A novel method is reported for forming polymer microparticles, which reduce atmospheric emissions of environmentally harmful volatile organic compounds such as toluene and xylene used as paint solvent in paint industry. The polymer microparticles have formed through rapid expansion from supercritical solution with a nonsolvent (RESS-N). Solubilization of poly(styrene)-b-(poly(methyl methacrylate)-co-poly (glycidyl methacrylate)) copolymer(PS-b-(PMMA-co-PGMA), MW = 5000, PS/PMMA/PGMA = 2/5/3), poly(ethylene glycol) (PEG, M. W = 4000), bisphenol A type epoxy resin (EP, MW = 3000), poly(methyl methacrylate) (PMMA; MW = 15000, 75000, 120000), and poly(oxyalkylene) alkylphenyl ether (MW = 4000) in carbon dioxide (CO2) was achieved with the use of small alcohols as cosolvents. The solubility of the PS-b-(PMMA-co-PGMA) is extremely low in either CO2 or ethanol but becomes 20 wt % in a mixture of the two. Because ethanol is a nonsolvent for the polymer, it can be used as a cosolvent in rapid expansion from supercritical solution to produce 1-3 microm particles that do not agglomerate. Obtained polymer particles by RESS-N were applied as powder coatings. The resulting coatings have a smooth and coherent film. The particle size distribution of microspheres was controlled by changing the polymer concentration, preexpansion pressure, temperature, and injection distance. The feed compositions were more effective than the other factors in controlling the particle size. The polymeric microparticles formed by RESS-N method can be utilized to make the thin coating film without anytoxic organic solvents and/or surfactants.

  17. Analysis of non-phthalates plasticizers on porous graphitic carbon by supercritical fluid chromatography using evaporative light scattering detection.

    Science.gov (United States)

    Vaccher, Claude; Decaudin, Bertrand; Sautou, Valérie; Lecoeur, Marie

    2014-09-12

    The analysis of several plasticizers, widely used in the production of medical devices, was investigated on porous graphitic carbon (PGC) stationary phase in supercritical fluid chromatography (SFC) with an evaporative light scattering detector (ELSD). Due to strong interaction of compounds with the PGC support, solvents of strong eluotropic strength were added to the CO2 supercritical fluid. The effect of alkyl chain (pentane, hexane, heptane) and chlorinated (CH2Cl2, CHCl3, CCl4) solvents was studied on the retention and on the ELSD detection of plasticizers. A co-solvent mixture composed of CHCl3/heptane, eluted under gradient mode, allowed a significant improvement of the ELSD response compared to the use of each solvent individually. Then, a central composite design (CCD) was implemented to optimize both the separation and the detection of plasticizers. The parameters involved were the outlet pressure, the gradient slope, the co-solvent composition and the drift tube temperature of the ELSD. After optimization, baseline separation of plasticizers was achieved in 7min and best signal-to-noise ratios were obtained with outlet pressure and drift tube temperature of ELSD set at 200bar and 31°C, respectively. The co-solvent mixture was also composed of CHCl3/heptane (35/65 v/v) and a gradient from 15 to 60% of co-solvent in 2.2min was employed. The results demonstrated that CCD is a powerful tool for the optimization of SFC/ELSD method and the response surface model analysis can provide statistical understandings of the significant factors required to achieve optimal separation and ELSD sensitivity.

  18. Application of aluminum-supported Pd, Rh, and Rh-Pd nanoparticles in supercritical carbon dioxide system for hydrodebromination of polybrominated diphenyl ethers.

    Science.gov (United States)

    Wu, Ben-Zen; Sun, Yu-Jie; Chen, Yan-Hua; Yak, Hwa Kwang; Yu, Jya-Jyun; Liao, Weisheng; Chiu, KongHwa; Peng, Shie-Ming

    2016-08-01

    Al-powder-supported Pd, Rh, and Rh-Pd catalysts were synthesized through a spontaneous redox reaction in aqueous solutions. These catalysts hydrodebrominated 4- and 4,4'-bromodiphenyl ethers in supercritical carbon dioxide at 200 atm CO2 containing 10 atm H2 and 80 °C in 1 h. Diphenyl ether was the major product of Pd/Al. Rh/Al and Rh-Pd/Al further hydrogenated two benzene rings of diphenyl ether to form dicyclohexyl ether. The hydrogenolysis of CO bonds on diphenyl ether over Rh/Al and Rh-Pd/Al was observed to generate cyclohexanol and cyclohexane (Rh-Pd/Al among three catalysts is suggested to be used for ex situ degradation of polybrominated diphenyl ethers in supercritical carbon dioxide. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. 超临界条件下烯烃氢甲酰化的研究进展%The Process of Hydroformylation of Olefins in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    周海军; 张业; 谢鲜梅; 陈小平

    2011-01-01

    综述了超临界CO2下烯烃氢甲酰化反应的研究进展,分析比较了均相和多相体系下催化反应的特点,并结合分离以及催化剂的回收利用等内容,对于该反应技术的未来发展与应用提出展望。%The Process of Hydroformylation of Olefins in Supercritical Carbon Dioxide. In this work, taking the reactions of homogeneous catalysis and heterogeneous catalysis, recent research progress about the catalyst recovery and utilization in Supercritical Carbon Dioxide were reviewed. Finally, the developing trends are discussed.

  20. Wheat germ oil extracted by supercritical carbon dioxide with ethanol: Fatty acid composition

    Directory of Open Access Journals (Sweden)

    Parczewska-Plesnar, B.

    2016-09-01

    Full Text Available In this work, supercritical fluid extraction (SFE using CO2 with ethanol as entrainer was performed at a temperature of 40 oC under a pressure of 21 MPa. For comparison, a similar extraction without the entrainer was carried out. The extraction yield of wheat germ using supercritical CO2 with ethanol was slightly higher (10.7 wt% than that of extraction without the entrainer (9.9 wt%. Fractions of SFE extracts were collected separately during the experiments and the composition of fatty acids in each fraction was analyzed. The SFE extracted oils were rich (63.4-71.3% in the most valuable polyunsaturated fatty acids (PUFA and their content in all collected fractions was approximately constant. Similar PUFA contents were found in the reference samples of oils extracted by n-hexane (66.2-67.0%, while the commercial cold-pressed oil contained significantly less PUFA (60.2%. These results show a higher nutritional value of the oil obtained by extraction with supercritical CO2 than cold pressed oil which is generally considered to be very valuable.En este trabajo, la extracción con fluidos supercríticos (SFE usando CO2 con etanol como agente de arrastre se realizó a 40 °C bajo una presión de 21 MPa. Se ha llevado a cabo la comparación con una extracción similar sin agente de arrastre. El rendimiento de la extracción de germen de trigo usando CO2 supercrítico con etanol fue ligeramente mayor (10,7% en peso que la de extracción sin agente de arrastre (9,9% en peso. Se recogieron por separado fracciones de extractos SFE durante los experimentos y se analizó la composición de ácidos grasos en cada fracción. Los aceites extraídos mediante SFE eran ricos en los ácidos grasos poliinsaturados más valiosos (63,4-71,3%, (PUFA y su contenido en todas las fracciones recogidas fue aproximadamente constante. Un contenido similar de PUFA fueron encontrados en muestras de referencia de los aceites extraídos con n-hexano (66,2-67,0%, mientras que el

  1. Subcritical and supercritical technology for the production of second generation bioethanol.

    Science.gov (United States)

    Rostagno, Mauricio A; Prado, Juliana M; Mudhoo, Ackmez; Santos, Diego T; Forster-Carneiro, Tânia; Meireles, M Angela A

    2015-01-01

    There is increased interest in reducing our reliance on fossil fuels and increasing the share of renewable raw materials in our energy supply chain due to environmental and economic concerns. Ethanol is emerging as a potential alternative to liquid fuels due to its eco-friendly characteristics and relatively low production costs. As ethanol is currently produced from commodities also used for human and animal consumption, there is an urgent need of identifying renewable raw materials that do not pose a competitive problem. Lignocellulosic agricultural residues are an ideal choice since they can be effectively hydrolyzed to fermentable sugars and integrated in the context of a biorefinery without competing with the food supply chain. However, the conventional hydrolysis methods still have major issues that need to be addressed. These issues are related to the processing rate and generation of fermentation inhibitors, which can compromise the quality of the product and the cost of the process. As the knowledge of the processes taking place during hydrolysis of agricultural residues is increasing, new techniques are being exploited to overcome these drawbacks. This review gives an overview of the state-of-the-art of hydrolysis with subcritical and supercritical water in the context of reusing agricultural residues for the production of suitable substrates to be processed during the fermentative production of bioethanol. Presently, subcritical and/or supercritical water hydrolysis has been found to yield low sugar contents mainly due to concurrent competing degradation of sugars during the hydrothermal processes. In this line of thinking, the present review also revisits the recent applications and advances to provide an insight of future research trends to optimize on the subcritical and supercritical process kinetics.

  2. Numerical Study on the Heat Transfer of Carbon Dioxide in Horizontal Straight Tubes under Supercritical Pressure.

    Directory of Open Access Journals (Sweden)

    Mei Yang

    Full Text Available Cooling heat transfer of supercritical CO2 in horizontal straight tubes with wall is numerically investigated by using FLUENT. The results show that almost all models are able to present the trend of heat transfer qualitatively, and the stand k-ε with enhanced wall treatment model shows the best agreement with the experimental data, followed by LB low Re turbulence model. Then further studies are discussed on velocity, temperature and turbulence distributions. The parameters which are defined as the criterion of buoyancy effect on convection heat transfer are introduced to judge the condition of the fluid. The relationships among the inlet temperature, outlet temperature, the mass flow rate, the heat flux and the diameter are discussed and the difference between the cooling and heating of CO2 are compared.

  3. Theoretical Studies on Critical Properties of Binary System with Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new expression of mixing rule is suggested according to the Mayson′s mixing rule in this paper, which adopts the Redlich-Kwong cubic equation of state and the modified Chueh-Prausnitz method to calculate the experiment critical points of six binary mixtures CO2+toluene, CO2+cyclohexane, CO2+n-butanal, CO2+i-butanal, CO2+methanol, CO2+ethanol. The coefficients of interaction parameter in the expression of mixing rule were optimized from experimental data. The calculated results of critical temperature and critical pressure meet the experiment data well. The maximum relative errors of temperature and pressure between the calculation results and experiment data are 1.493% and 5.2236% respectively, indicating that the proposed expression of mixing rule is reasonable. This may provide a fundamental method for studying and predicting the properties of supercritical fluids.

  4. Numerical Study on the Heat Transfer of Carbon Dioxide in Horizontal Straight Tubes under Supercritical Pressure.

    Science.gov (United States)

    Yang, Mei

    2016-01-01

    Cooling heat transfer of supercritical CO2 in horizontal straight tubes with wall is numerically investigated by using FLUENT. The results show that almost all models are able to present the trend of heat transfer qualitatively, and the stand k-ε with enhanced wall treatment model shows the best agreement with the experimental data, followed by LB low Re turbulence model. Then further studies are discussed on velocity, temperature and turbulence distributions. The parameters which are defined as the criterion of buoyancy effect on convection heat transfer are introduced to judge the condition of the fluid. The relationships among the inlet temperature, outlet temperature, the mass flow rate, the heat flux and the diameter are discussed and the difference between the cooling and heating of CO2 are compared.

  5. Isolation of Bioactive Compounds from Sunflower Leaves (Helianthus annuus L.) Extracted with Supercritical Carbon Dioxide.

    Science.gov (United States)

    El Marsni, Zouhir; Torres, Ascension; Varela, Rosa M; Molinillo, José M G; Casas, Lourdes; Mantell, Casimiro; Martinez de la Ossa, Enrique J; Macias, Francisco A

    2015-07-22

    The work described herein is a continuation of our initial studies on the supercritical fluid extraction (SFE) with CO2 of bioactive substances from Helianthus annuus L. var. Arianna. The selected SFE extract showed high activity in the wheat coleoptile bioassay, in Petri dish phytotoxicity bioassays, and in the hydroponic culture of tomato seeds. Chromatographic fractionations of the extracts and a spectroscopic analysis of the isolated compounds showed 52 substances belonging to 10 different chemical classes, which were mainly sesquiterpene lactones, diterpenes, and flavonoids. Heliannuol M (31), helivypolides K and L (36, 37), and helieudesmanolide B (38) are described for the first time in the literature. Metabolites have been tested in the etiolated wheat coleoptile bioassay with good results in a noteworthy effect on germination. The most active compounds were also tested on tomato seeds, heliannuol A (30) and leptocarpin (45) being the most active, with values similar to those of the commercial herbicide.

  6. Ranking of enabling technologies for oxy-fuel based carbon capture

    Energy Technology Data Exchange (ETDEWEB)

    Ochs, T.L.; Oryshchyn, D.L.; Ciferno, J.P.

    2007-06-01

    The USDOE National Energy Technology Laboratory (NETL) has begun a process to identify and rank enabling technologies that have significant impacts on pulverized coal oxy-fuel systems. Oxy-fuel combustion has been identified as a potential method for effectively capturing carbon in coal fired power plants. Presently there are a number of approaches for carbon capture via oxy-fuel combustion and it is important to order those approaches so that new research can concentrate on those technologies with high potentials to substantially lower the cost of reduced carbon electricity generation. NETL evaluates these technologies using computer models to determine the energy use of each technology and the potential impact of improvements in the technologies on energy production by a power plant. Near-term sub-critical boiler technologies are targeted for this analysis because: • most of the world continues to build single reheat sub-critical plants; • the overwhelming number of coal fired power plants requiring retrofit for CO2 capture are sub-critical plants. In addition, even in the realm of new construction, subcritical plants are common because they are well understood, easy to operate and maintain, fuel tolerant, and reliable. Following the initial investigation into sub-critical oxy-fuel technology, future investigations will move into the supercritical range.

  7. Enhancement of cemented waste forms by supercritical CO{sub 2} carbonation of standard portland cements

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, J.B.; Carey, J.; Taylor, C.M.V.

    1997-08-01

    We are conducting experiments on an innovative transformation concept, using a traditional immobilization technique, that may significantly reduce the volume of hazardous or radioactive waste requiring transport and long-term storage. The standard practice for the stabilization of radioactive salts and residues is to mix them with cements, which may include additives to enhance immobilization. Many of these wastes do not qualify for underground disposition, however, because they do not meet disposal requirements for free liquids, decay heat, head-space gas analysis, and/or leachability. The treatment method alters the bulk properties of a cemented waste form by greatly accelerating the natural cement-aging reactions, producing a chemically stable form having reduced free liquids, as well as reduced porosity, permeability and pH. These structural and chemical changes should allow for greater actinide loading, as well as the reduced mobility of the anions, cations, and radionuclides in aboveground and underground repositories. Simultaneously, the treatment process removes a majority of the hydrogenous material from the cement. The treatment method allows for on-line process monitoring of leachates and can be transported into the field. We will describe the general features of supercritical fluids, as well as the application of these fluids to the treatment of solid and semi-solid waste forms. some of the issues concerning the economic feasibility of industrial scale-up will be addressed, with particular attention to the engineering requirements for the establishment of on-site processing facilities. Finally, the initial results of physical property measurements made on portland cements before and after supercritical fluid processing will be presented.

  8. Neutron scattering characterization of homopolymers and graft-copolymer micelles in supercritical carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Chillura-Martino, D; Triolo, R. [Palermo Univ. (Italy). Ist. di Chimica Fisica; McClain, J.B. [North Carolina Univ., Chapel Hill, NC (United States)] [and others

    1995-12-31

    Supercritical fluids are becoming an attractive alternative to the liquid solvents traditionally used as polymerization media. As the synthesis proceeds, a wide range of colloidal aggregates form, but there has hitherto been no way to measure such structures directly. We have applied small-angle neutron scattering (SANS) to characterize such systems, and although SCF polymerizations are carried out at high pressures, the penetrating power of the neutron beam means that typical cell windows are virtually transparent. Systems studied include molecules soluble in CO{sub 2} (e.g. polyfluoro-octyl acrylate or PFOA) and this polymer has previously been shown to exhibit a positive second virial coefficient (A{sub 2}). Other CO{sub 2}-soluble polymers include hexafluoro-polypropylene oxide (HFPPO), which appears to have a second virial coefficient which is close to zero (10{sup 4}A{sub 2} {approx_equal} 0 +{+-} 0.2 cm{sup 3} g{sup -2} mol). Polydimethylsiloxane (PDMS), is soluble on the molecular level only in the limit of dilute solution and seems to form aggregates as the concentration increases (c > 0.01 g cm{sup -3}). Other polymers (e.g. polystyrene) are insoluble in CO{sub 2}, though polymerizations may be accomplished via the use of PS-PFOA blockcopolymer stabilizers, which are also amenable to SANS characterization, and have been shown to form micelles in CO{sub 2}. Other amphiphilic surfactant molecules that form micelles include PFOA-polyethylene oxide (PFOA-PEO) graft copolymers, which swell as the CO{sub 2} medium is saturated with water. These systems have been characterized by SANS, by taking advantage of the different contrast options afforded by substituting D{sub 2}O for H{sub 2}O. This paper illustrates the utility of SANS to measure molecular dimensions, thermodynamic variables, molecular weights, micelle structures etc. in supercritical CO{sub 2}.

  9. A supercritical fluid-based coating technology. 3: preparation and characterization of bovine serum albumin particles coated with lipids.

    Science.gov (United States)

    Ribeiro Dos Santos, I; Richard, J; Thies, C; Pech, B; Benoit, J-P

    2003-01-01

    Solvent-free microparticles, loaded with bovine serum albumin as a model protein, were produced using a novel supercritical (SC) fluid-based coating technology. Coating material consists either of trimyristin (Dynasan 114) or of Gelucire 50-02. Microparticles obtained were characterized as regards their morphology, protein content and in vitro release profile. A discontinuous coating made of micro-needles of trimyristin led to an initial burst release of approximately 70% in 30 min. However, a prolonged release of the BSA could be achieved in a phosphate buffer solution at 37 degrees C over a 24 h period from particles coated with Gelucire 50-02. Furthermore, it was shown that BSA does not undergo any degradation after SC CO(2) treatment under the conditions used in the coating process.

  10. Supercritical Fluid Reactions for Coal Processing

    Energy Technology Data Exchange (ETDEWEB)

    Charles A. Eckert

    1997-11-01

    Exciting opportunities exist for the application of supercritical fluid (SCF) reactions for the pre-treatment of coal. Utilizing reactants which resemble the organic nitrogen containing components of coal, we developed a method to tailor chemical reactions in supercritical fluid solvents for the specific application of coal denitrogenation. The tautomeric equilibrium of a Schiff base was chosen as one model system and was investigated in supercritical ethane and cosolvent modified supercritical ethane. The Diels-Alder reaction of anthracene and 4-phenyl-1,2,4-triazoline-3,5-dione (PTAD) was selected as a second model system, and it was investigated in supercritical carbon dioxide.

  11. Comparison of the Anti-Inflammatory Activities of Supercritical Carbon Dioxide versus Ethanol Extracts from Leaves of Perilla frutescens Britt. Radiation Mutant.

    Science.gov (United States)

    Jin, Chang Hyun; Park, Han Chul; So, Yangkang; Nam, Bomi; Han, Sung Nim; Kim, Jin-Baek

    2017-02-17

    In this study, we aimed to compare supercritical carbon dioxide extraction and ethanol extraction for isoegomaketone (IK) content in perilla leaf extracts and to identify the optimal method. We measured the IK concentration using HPLC and inflammatory mediators in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells from the extracts. The IK concentration was 10-fold higher in perilla leaf extracts by supercritical carbon dioxide extraction (SFE) compared with that in perilla leaf extracts by ethanol extraction (EE). When the extracts were treated in LPS-induced RAW 264.7 cells at 25 μg/mL, the SFE inhibited the expression of inflammatory mediators such as nitric oxide (NO), monocyte chemoattractant protein-1 (MCP-1), interleutkin-6 (IL-6), interferon-β (IFN-β), and inducible nitric oxide synthase (iNOS) to a much greater extent compared with EE. Taken together, supercritical carbon dioxide extraction is considered the optimal process for obtaining high IK content and anti-inflammatory activities in leaf extracts from the P. frutescens Britt. radiation mutant.

  12. Numerical analysis of air-foil shaped fin performance in printed circuit heat exchanger in a supercritical carbon dioxide power cycle

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Ho [Department of Mechanical Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Kwon, Jin Gyu [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Yoon, Sung Ho [Korea Institute of Nuclear Nonproliferation and Control, Daejeon 305-348 (Korea, Republic of); Park, Hyun Sun, E-mail: hejsunny@postech.ac.kr [Division of Advanced Nuclear Engineering, POSTECH, Pohang 790-784 (Korea, Republic of); Kim, Moo Hwan [Korea Institute of Nuclear Safety, Daejeon 305-338 (Korea, Republic of); Cha, Jae Eun [Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of)

    2015-07-15

    Highlights: • Staggered arrangement affects the pressure drop but does not significantly affect to the heat transfer. • The total pressure drop is reduced, but the amount of acceleration pressure drop increases while that of frictional pressure drop decreases as the horizontal number increases. • For the vertical number, the total pressure drop decreases more largely than the horizontal number. • The objective function shows that the fully staggered arrangement shows best performance. - Abstract: One of the key issues of the PCHE technology in the supercritical CO{sub 2} Brayton cycle is to achieve an efficient and compact designs to be able to enhance heat transfer and reduce pressure drop. The issue is challenging due to the complex configuration of micro-channels in the PCHE. In this study, an innovative micro-channel equipped with an array of airfoil fins is analyzed to evaluate its performance. In so doing, sensitivity analysis with various design parameters is performed to configure the optimal arrangement of airfoil fins by using CFD analysis for Supercritical Carbon dioxide Integral Experimental Loop (SCIEL) in Korean Atomic Energy Research Institute (KAERI). Dominant geometric parameters of the fin arrangement that affects to the thermal and hydraulic performances are the horizontal, vertical and staggered pitches. ANSYS ICEM CFD and ANSYS CFX are used for the grid generation and the computational calculation. CO{sub 2} properties are used by using REFPROF software database. The inlet temperature of the hot side is 618 K and that of the cold side is 585 K. The reference mass flow rate is set as 1.2 g/s for the vertical number of 2.0, which is the Reynolds number of about 30,000. The mass flow rate changes from 0.4 to 4.8 g/s in order to investigate the Reynolds number effect. The k-ε model is selected as the turbulence model. In conclusions, the results show that the optimal arrangement of airfoil fins can be examined in terms of an objective

  13. Technological Development in Carbon Sequestration at Petrobras

    Energy Technology Data Exchange (ETDEWEB)

    Castello Branco, R.; Vazquez Sebastian, G.; Murce, T.; Cunha, P.; Dino, R.; Sartori Santarosa, C.

    2007-07-01

    Petrobras defined, in its mission, the intention to act in a safe and profitable way, with social and environmental responsibility. In its vision, the company decided to be an oil and energy company, taking into account climate change mitigation. These changes were partially caused, without the company's knowledge, for many years, by the burning of fossil fuels. Among many technologies available for this mitigation, carbon sequestration is the one that, in a short space of time, can avoid the collapse of earth's climate. In order to meet this carbon sequestration challenge, there has been established, at CENPES, three strategies for its technological development: (i) establishment of a Systemic Project for Carbon Sequestration within the scope of the Environmental Technology Program - PROAMB; (ii) creation of a Group of Carbon Sequestration Technologies for Climate Change Mitigation - formation of team and qualification program, which includes the realization of the International Seminar on Carbon Sequestration and Climate Change at Petrobras in October 2006; and (iii) Implementation of the Technological Network of Technologies for Climate Change Mitigation. (auth)

  14. Novel polymer composites from waste ethylene-propylene-diene-monomer rubber by supercritical CO2 foaming technology.

    Science.gov (United States)

    Jeong, Keuk Min; Hong, Yeo Joo; Saha, Prosenjit; Park, Seong Ho; Kim, Jin Kuk

    2014-11-01

    In this study, a composite has been prepared by mixing waste rubber, such as ethylene-propylene-diene-monomer and low-density poly ethylene foaming, with supercritical carbon dioxide. In order to optimise the foaming process of the waste ethylene-propylene-diene-monomer-low-density poly ethylene composite, the variations of pressure and temperature on the foamed Microcell formation were studied. As indicated in scanning electron microscope photographs, the most uniform microcellular pattern was found at 200 bar and 100 °C using 30% by weight of waste ethylene-propylene-diene-monomer. Carbon dioxide could not be dissolved uniformly during foaming owing to extensive cross-linking of the waste ethylene-propylene-diene-monomer used for the composite. As a result the presence of un-uniform microcells after foaming were observed in the composite matrix to impart inferior mechanical properties of the composite. This problem was solved with uniform foaming by increasing the cross-link density of low-density poly ethylene using 1.5 parts per hundred dicumyl peroxide that enhances composite tensile and compressive strength up to 57% and 15%, respectively. The composite has the potential to be used as a foaming mat for artificial turf.

  15. Review of supercritical CO2 power cycle technology and current status of research and development

    Directory of Open Access Journals (Sweden)

    Yoonhan Ahn

    2015-10-01

    Full Text Available The supercritical CO2 (S-CO2 Brayton cycle has recently been gaining a lot of attention for application to next generation nuclear reactors. The advantages of the S-CO2 cycle are high efficiency in the mild turbine inlet temperature region and a small physical footprint with a simple layout, compact turbomachinery, and heat exchangers. Several heat sources including nuclear, fossil fuel, waste heat, and renewable heat sources such as solar thermal or fuel cells are potential application areas of the S-CO2 cycle. In this paper, the current development progress of the S-CO2 cycle is introduced. Moreover, a quick comparison of various S-CO2 layouts is presented in terms of cycle performance.

  16. Carotenoids, Fatty Acid Composition and Heat Stability of Supercritical Carbon Dioxide-Extracted-Oleoresins

    Directory of Open Access Journals (Sweden)

    Antonella Leone

    2012-03-01

    Full Text Available The risk of chronic diseases has been shown to be inversely related to tomato intake and the lycopene levels in serum and tissue. Cis-isomers represent approximately 50%–80% of serum lycopene, while dietary lycopene maintains the isomeric ratio present in the plant sources with about 95% of all-trans-lycopene. Supercritical CO2 extraction (S-CO2 has been extensively developed to extract lycopene from tomato and tomato processing wastes, for food or pharmaceutical industries, also by using additional plant sources as co-matrices. We compared two S-CO2-extracted oleoresins (from tomato and tomato/hazelnut matrices, which showed an oil-solid bi-phasic appearance, a higher cis-lycopene content, and enhanced antioxidant ability compared with the traditional solvent extracts. Heat-treating, in the range of 60–100 °C, led to changes in the lycopene isomeric composition and to enhanced antioxidant activity in both types of oleoresins. The greater stability has been related to peculiar lycopene isomer composition and to the lipid environment. The results indicate these oleoresins are a good source of potentially healthful lycopene.

  17. Supercritical carbon dioxide pretreatment of corn stover and switchgrass for lignocellulosic ethanol production.

    Science.gov (United States)

    Narayanaswamy, Naveen; Faik, Ahmed; Goetz, Douglas J; Gu, Tingyue

    2011-07-01

    Supercritical CO(2) (SC-CO(2)), a green solvent suitable for a mobile lignocellulosic biomass processor, was used to pretreat corn stover and switchgrass at various temperatures and pressures. The CO(2) pressure was released as quickly as possible by opening a quick release valve during the pretreatment. The biomass was hydrolyzed after pretreatment using cellulase combined with β-glucosidase. The hydrolysate was analyzed for the amount of glucose released. Glucose yields from corn stover samples pretreated with SC-CO(2) were higher than the untreated sample's 12% glucose yield (12 g/100g dry biomass) and the highest glucose yield of 30% was achieved with SC-CO(2) pretreatment at 3500 psi and 150°C for 60 min. The pretreatment method showed very limited improvement (14% vs. 12%) in glucose yield for switchgrass. X-ray diffraction results indicated no change in crystallinity of the SC-CO(2) treated corn stover when compared to the untreated, while SEM images showed an increase in surface area.

  18. Molecular Simulation Study of Montmorillonite in Contact with Variably Wet Supercritical Carbon Dioxide

    KAUST Repository

    Kadoura, Ahmad Salim

    2017-03-07

    We perform grand canonical Monte Carlo simulations to study the detailed molecular mechanism of intercalation behavior of CO2 in Na-, Ca-, and Mg- montmorillonite exposed to variably hydrated supercritical CO2 at 323.15 K and 90 bar, The simulations indicate that the intercalation of CO2 strongly depends on the relative humidity (RH). The intercalation of CO2 in the dehydrated interlayer is inhibited, followed by the swelling of the interlayer region due to uptake of water and CO2 as the RH increases. In all of the hydrated clay samples, the amount of the intercalated CO2 generally decreases as a function of increasing RH, which is attributed mainly to the weakening of the interaction between CO2 and clay. At low RH values, Ca- and Mg- montmorillonite are relatively more efficient in capturing CO2. The amount of CO2 trapped in all clay samples shows similar values above RH of similar to 60%. Molecular dynamics simulations show that the diffusion coefficient of each species generally increases with increasing RH due to the associated expansion of the interlayer distance of the clay. For all the hydrated samples, the diffusion coefficients of CO2 and water in the interlayers are mostly comparable due to the fact that CO2 molecules are well solvated. The diffusion of CO2 in each hydration state is mostly independent of the type of cation in accordance with the fact that CO2 molecules hardly migrate into the first hydration shell of the interlayer cations.

  19. Carotenoids, fatty acid composition and heat stability of supercritical carbon dioxide-extracted-oleoresins.

    Science.gov (United States)

    Longo, Cristiano; Leo, Lucia; Leone, Antonella

    2012-01-01

    The risk of chronic diseases has been shown to be inversely related to tomato intake and the lycopene levels in serum and tissue. Cis-isomers represent approximately 50%-80% of serum lycopene, while dietary lycopene maintains the isomeric ratio present in the plant sources with about 95% of all-trans-lycopene. Supercritical CO(2) extraction (S-CO(2)) has been extensively developed to extract lycopene from tomato and tomato processing wastes, for food or pharmaceutical industries, also by using additional plant sources as co-matrices. We compared two S-CO(2)-extracted oleoresins (from tomato and tomato/hazelnut matrices), which showed an oil-solid bi-phasic appearance, a higher cis-lycopene content, and enhanced antioxidant ability compared with the traditional solvent extracts. Heat-treating, in the range of 60-100 °C, led to changes in the lycopene isomeric composition and to enhanced antioxidant activity in both types of oleoresins. The greater stability has been related to peculiar lycopene isomer composition and to the lipid environment. The results indicate these oleoresins are a good source of potentially healthful lycopene.

  20. Enzyme-aided extraction of lycopene from high-pigment tomato cultivars by supercritical carbon dioxide.

    Science.gov (United States)

    Lenucci, Marcello Salvatore; De Caroli, Monica; Marrese, Pier Paolo; Iurlaro, Andrea; Rescio, Leonardo; Böhm, Volker; Dalessandro, Giuseppe; Piro, Gabriella

    2015-03-01

    This work reports a novel enzyme-assisted process for lycopene concentration into a freeze-dried tomato matrix and describes the results of laboratory scale lycopene supercritical CO2 (SC-CO2) extractions carried out with untreated (control) and enzyme-digested matrices. The combined use of food-grade commercial plant cell-wall glycosidases (Celluclast/Novozyme plus Viscozyme) allows to increase lycopene (∼153%) and lipid (∼137%) concentration in the matrix and rises substrate load onto the extraction vessel (∼46%) compared to the control. The addition of an oleaginous co-matrix (hazelnut seeds) to the tomato matrix (1:1 by weight) increases CO2 diffusion through the highly dense enzyme-treated matrix bed and provides lipids that are co-extracted increasing lycopene yield. Under the same operative conditions (50 MPa, 86 °C, 4 mL min(-1) SC-CO2 flow) extraction yield from control and Celluclast/Novozyme+Viscozyme-treated tomato matrix/co-matrix mixtures was similar, exceeding 75% after 4.5h of extraction. However, the total extracted lycopene was ∼3 times higher in enzyme-treated matrix than control.

  1. A nanosystem for water-insoluble drugs prepared by a new technology, nanoparticulation using a solid lipid and supercritical fluid.

    Science.gov (United States)

    Park, Joo Won; Yun, Jeong Min; Lee, Eun Seong; Youn, Yu Seok; Kim, Kab Sig; Oh, Young Taik; Oh, Kyung Teak

    2013-11-01

    While the number and diversity of lead compounds has increased with the development of science technologies, ca. 90 % of new chemical entities under development have shown low aqueous solubility, classified as class II or IV of the biopharmaceutics classification system (BCS). The low aqueous solubility hinders their clinical translations due to low bioavailability and dissolution-limited absorption of orally-administered drugs. Several technologies have been employed to improve the solubility of poorly water-soluble drugs. In this paper, a new method of nanoparticulation using fat and a supercritical fluid (NUFS) for the formulation of hydrophobic drugs was applied to solve the low solubility problem. A typical BCS class II drug, itraconazole, was selected and formulated with hydroxypropyl methylcellulose, emulsification, and anticoagulating agents for NUFS. The non-spherical itraconazole nanoparticles prepared by NUFS were ~300-500 nm in size with a ~15-fold improved dissolution rate compared to non-nanoparticles of itraconazole (i.e., raw itraconazole). In addition, a high drug content of ~46 % by weight and a drug loading efficiency greater than 85 % were achieved. Therefore, the new technology for nano-platforms could be a promising solution for solubilization of poorly water-soluble drugs, resulting in improved bioavailability.

  2. Antioxidants from grape seed using supercritical carbon dioxide; Obtencion de antioxidantes a partir de pepitas de uva mediante extraccion con fluidas superciriticas, SFE

    Energy Technology Data Exchange (ETDEWEB)

    Acilu, M.; Berganza, J.; Brettes, P.

    2003-07-01

    The wine-producing industry produces large amount of solid waste annually. Grape seeds represent a large percentage of this solid waste, the production of vegetable oil and energy being the more usual added value. As it is known, grape seeds contain huge amounts of phenolic compounds and have been highly researched owing to their antoxidant properties. The aim of this article is to present the extraction results of these compounds from grape seeds using supercritical carbon dioxide. Before doing the final experiments in the pilot plant of supercritical fluids, the following variables were evaluated using analytical equipment: time extraction, pressure, temperature, amount, nature and method used for adding the modifiers, as well as pre-treatment and amount of raw material. The results showed that the recovery of phenolic compounds from real materials is lower than the recovery obtained with the standards, and that maximum extraction is achieved with monomeric compounds, mainly with epichatechin. (Author)

  3. Recent Progress in the Development of Supercritical Carbon Dioxide-Soluble Metal Ion Extractants: Aggregation, Extraction, and Solubility Properties of Silicon-Substituted Alkylenediphosphonic Acids

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, Mark L.; McAlister, Daniel R.; Stepinski, Dominique C.; Zalupski, Peter R.; Dzilawa, Julie A.; Barrans, Richard E.; Hess, J.N.; Rubas, Audris V.; Chiarizia, Renato; Lubbers, Christopher M.; Scurto, Aaron M.; Brennecke, Joan F.; Herlinger, Albert W.

    2003-09-11

    Partially esterified alkylenediphosphonic acids (DPAs) have been shown to be effective reagents for the extraction of actinide ions from acidic aqueous solution into conventional organic solvents. Efforts to employ these compounds in supercritical fluid extraction have been hampered by their modest solubility in unmodified supercritical carbon dioxide (SC-CO2). In an effort to design DPAs that are soluble in SC-CO2, a variety of silicon-substituted alkylenediphosphonic acids have been prepared and characterized, and their behavior compared with that of conventional alkyl-substituted reagents. Silicon substitution is shown to enhance the CO2-philicity of the reagents, while other structural features, in particular, the number of methylene groups bridging the phosphorus atoms of the extractant, are shown to exert a significant influence on their aggregation and extraction properties. The identification of DPAs combining desirable extraction properties with adequate solubility in SC-CO2 is shown to be facilitated by the application of molecular connectivity indices.

  4. Continuous-flow Heck synthesis of 4-methoxybiphenyl and methyl 4-methoxycinnamate in supercritical carbon dioxide expanded solvent solutions

    Directory of Open Access Journals (Sweden)

    Phei Li Lau

    2013-12-01

    Full Text Available The palladium metal catalysed Heck reaction of 4-iodoanisole with styrene or methyl acrylate has been studied in a continuous plug flow reactor (PFR using supercritical carbon dioxide (scCO2 as the solvent, with THF and methanol as modifiers. The catalyst was 2% palladium on silica and the base was diisopropylethylamine due to its solubility in the reaction solvent. No phosphine co-catalysts were used so the work-up procedure was simplified and the green credentials of the reaction were enhanced. The reactions were studied as a function of temperature, pressure and flow rate and in the case of the reaction with styrene compared against a standard, stirred autoclave reaction. Conversion was determined and, in the case of the reaction with styrene, the isomeric product distribution was monitored by GC. In the case of the reaction with methyl acrylate the reactor was scaled from a 1.0 mm to 3.9 mm internal diameter and the conversion and turnover frequency determined. The results show that the Heck reaction can be effectively performed in scCO2 under continuous flow conditions with a palladium metal, phosphine-free catalyst, but care must be taken when selecting the reaction temperature in order to ensure the appropriate isomer distribution is achieved. Higher reaction temperatures were found to enhance formation of the branched terminal alkene isomer as opposed to the linear trans-isomer.

  5. Microscopic structure and interaction analysis for supercritical carbon dioxide-ethanol mixtures: a Monte Carlo simulation study.

    Science.gov (United States)

    Xu, Wenhao; Yang, Jichu; Hu, Yinyu

    2009-04-01

    Configurational-bias Monte Carlo simulations in the isobaric-isothermal ensemble using the TraPPE-UA force field were performed to study the microscopic structures and molecular interactions of mixtures containing supercritical carbon dioxide (scCO(2)) and ethanol (EtOH). The binary vapor-liquid coexisting curves were calculated at 298.17, 333.2, and 353.2 K and are in excellent agreement with experimental results. For the first time, three important interactions, i.e., EtOH-EtOH hydrogen bonding, EtOH-CO(2) hydrogen bonding, and EtOH-CO(2) electron donor-acceptor (EDA) bonding, in the mixtures were fully analyzed and compared. The EtOH mole fraction, temperature, and pressure effect on the three interactions was investigated and then explained by the competition of interactions between EtOH and CO(2) molecules. Analysis of the microscopic structures indicates a strong preference for the formation of EtOH-CO(2) hydrogen-bonded tetramers and pentamers at higher EtOH compositions. The distribution of aggregation sizes and types shows that a very large EtOH-EtOH hydrogen-bonded network exists in the mixtures, while only linear EtOH-CO(2) hydrogen-bonded and EDA-bonded dimers and trimers are present. Further analysis shows that EtOH-CO(2) EDA complex is more stable than the hydrogen-bonded one.

  6. A computer simulation study on self- and cross-aggregation of multiple polar species in supercritical carbon dioxide.

    Science.gov (United States)

    Xu, Wenhao; Yang, Jichu

    2010-04-29

    The effect of hydrogen-bond cooperativity on self- and cross-aggregation of multiple polar species in supercritical carbon dioxide was investigated using both ab initio calculations and Monte Carlo simulations. Ab initio calculations indicate that hydrogen-bond cooperativity has a significant impact on the cluster size, but does not greatly influence the composition of clusters. The microscopic structures in the ethanol + CO(2) and acetic acid + CO(2) binary mixtures were first studied using Monte Carlo simulations with a strict set of criteria for hydrogen bonding, and a satisfactory agreement with experimental data was achieved. The state of microscopic phase separation in the ethanol + water + CO(2) and acetic acid + water + CO(2) ternary mixtures was then extensively investigated, indicating that the size and composition of aggregates are strongly dependent on the mixing ratio. Moreover, hydrogen-bond cooperativity must be considered to acquire more thorough understanding of the hydration process. On the basis of the detailed distributions of aggregate size and structure, a new two-staged hydration mechanism was finally proposed for the ternary solutions.

  7. Cytotoxic Activity of Kenaf Seed Oils from Supercritical Carbon Dioxide Fluid Extraction towards Human Colorectal Cancer (HT29) Cell Lines.

    Science.gov (United States)

    Abd Ghafar, Siti Aisyah; Ismail, Maznah; Saiful Yazan, Latifah; Fakurazi, Sharida; Ismail, Norsharina; Chan, Kim Wei; Md Tahir, Paridah

    2013-01-01

    Kenaf (Hibiscus cannabinus) from the family Malvaceae, is a valuable fiber plant native to India and Africa and is currently planted as the fourth commercial crop in Malaysia. Kenaf seed oil contains alpha-linolenic acid, phytosterol such as β -sitosterol, vitamin E, and other antioxidants with chemopreventive properties. Kenaf seeds oil (KSO) was from supercritical carbon dioxide extraction fluid (SFE) at 9 different permutations of parameters based on range of pressures from 200 to 600 bars and temperature from 40 to 80°C. They were 200/40, 200/60, 200/80, 400/40, 400/60, 400/80, 600/40, 600/60, and 600/80. Extraction from 9 parameters of KSO-SFE was screened for cytotoxicity towards human colorectal cancer cell lines (HT29) and mouse embryonic fibroblast (NIH/3T3) cell lines using MTS assay. KSO-SFE at 600/40 showed the strongest cytotoxicity towards HT29 with IC50 of 200 µg/mL. The IC50 for NIH/3T3 was not detected even at highest concentration employed. Cell cycle analysis showed a significant increase in the accumulation of KSO-SFE-treated cells at sub-G1 phase, indicating the induction of apoptosis by KSO-SFE. Further apoptosis induction was confirmed by Annexin V/PI and AO/PI staining.

  8. Determination of Oleanolic and Ursolic Acids in Hedyotis diffusa Using Hyphenated Ultrasound-Assisted Supercritical Carbon Dioxide Extraction and Chromatography

    Directory of Open Access Journals (Sweden)

    Ming-Chi Wei

    2015-01-01

    Full Text Available Oleanolic acid (OA and ursolic acid (UA were extracted from Hedyotis diffusa using a hyphenated procedure of ultrasound-assisted and supercritical carbon dioxide (HSC–CO2 extraction at different temperatures, pressures, cosolvent percentages, and SC–CO2 flow rates. The results indicated that these parameters significantly affected the extraction yield. The maximal yields of OA (0.917 mg/g of dry plant and UA (3.540 mg/g of dry plant were obtained at a dynamic extraction time of 110 min, a static extraction time of 15 min, 28.2 MPa, and 56°C with a 12.5% (v/v cosolvent (ethanol/water = 82/18, v/v and SC–CO2 flowing at 2.3 mL/min (STP. The extracted yields were then analyzed by high performance liquid chromatography (HPLC to quantify the OA and UA. The present findings revealed that H. diffusa is a potential source of OA and UA. In addition, using the hyphenated procedure for extraction is a promising and alternative process for recovering OA and UA from H. diffusa at high concentrations.

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

    Science.gov (United States)

    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.

  10. Transient analysis of subcritical/supercritical carbon dioxide based natural circulation loop with end heat exchangers: experimental study

    Science.gov (United States)

    Yadav, Ajay Kumar; Ramgopal, Maddali; Bhattacharyya, Souvik

    2017-09-01

    Carbon dioxide (CO2) based natural circulation loops (NCLs) has gained attention due to its compactness with higher heat transfer rate. In the present study, experimental investigations have been carried out to capture the transient behaviour of a CO2 based NCL operating under subcritical as well as supercritical conditions. Water is used as the external fluid in cold and hot heat exchangers. Results are obtained for various inlet temperatures (323-353 K) of water in the hot heat exchanger and a fixed inlet temperature (305 K) of cooling water in the cold heat exchanger. Effect of loop operating pressure (50-90 bar) on system performance is also investigated. Effect of loop tilt in two different planes (XY and YZ) is also studied in terms of transient as well as steady state behaviour of the loop. Results show that the time required to attain steady state decreases as operating pressure of the loop increases. It is also observed that the change in temperature of loop fluid (CO2) across hot or cold heat exchanger decreases as operating pressure increases.

  11. Supercritical carbon dioxide-assisted rapid synthesis of few-layer black phosphorus for hydrogen peroxide sensing.

    Science.gov (United States)

    Yan, Shancheng; Wang, Bojun; Wang, Zhulan; Hu, Dong; Xu, Xin; Wang, Junzhuan; Shi, Yi

    2016-06-15

    Solutions with large-scale dispersions of 2D black phosphorus (BP), often referred to as phosphorene, are obtained through solvent exfoliation. But, rapid phosphorene synthesis remains a challenge. Furthermore, although the chemical sensing capability of BP-based sensors has been theoretically predicted, its experimental verification remains lacking. In this study, we demonstrate the use of supercritical carbon dioxide-assisted rapid synthesis (5h) of few-layer BP. In addition, we construct a non-enzymatic hydrogen peroxide (H2O2) sensor based on few-layer BP for the first time to utilize BP degradation under ambient conditions. The proposed H2O2 sensor exhibits a considerably lower detection limit of 1 × 10(-7) M compared with the general detection limit of 1 × 10(-7) M-5 × 10(-5)M via electrochemical methods. Overall, the results of this study will not only expand the coverage of BP research but will also identify the important sensing characteristics of BP.

  12. Porous poly(D,L-lactic acid) foams with tunable structure and mechanical anisotropy prepared by supercritical carbon dioxide.

    Science.gov (United States)

    Floren, Michael; Spilimbergo, Sara; Motta, Antonella; Migliaresi, Claudio

    2011-11-01

    The design and tunability of tissue scaffolds, such as pore size and geometry, is crucial to the success of an engineered tissue replacement. Moreover, the mechanical nature of a tissue scaffold should display properties similar to the tissue of interest; therefore, tunability of the foam mechanical properties is desirable. Polymeric foams prepared using supercritical carbon dioxide as a blowing agent has emerged in recent years as a promising technique to prepare porous scaffolds. While a number of groups have reported on the tailoring of scaffold morphologies by using gas foaming techniques, few have considered the effects of such processing conditions on the physical and mechanical anisotropy achieved. The aim of this study was to demonstrate the tunability of the structure and mechanical anisotropy of foams prepared using a variety of different gas foaming conditions. Porous poly(D,L lactic acid) foams were prepared by the systematic adjustment of processing conditions, namely pressure, temperature and venting time, resulting in an extensive range of scaffold morphologies. Characterization of sample anisotropy was achieved by mechanical evaluation of foam specimens both longitudinal and transverse to the foaming direction. The obtained mechanical properties demonstrated a strong dependence of the processing conditions on mechanical anisotropy and performance. Furthermore, results indicate that factors other than pore geometry may be necessary to define the mechanical behavior of the foam specimens. The favorable compressive moduli, coupled with large degrees of anisotropy, suggests these foams may have suitable application as scaffolds for bone tissue engineering.

  13. Extraction of lycopene from tomato skin with supercritical carbon dioxide: effect of operating conditions and solubility analysis.

    Science.gov (United States)

    Topal, Ummihan; Sasaki, Mitsuru; Goto, Motonobu; Hayakawa, Kiro

    2006-07-26

    Supercritical carbon dioxide (SCCO2) extraction of lycopene from waste tomato skins was investigated. The experiments were carried out at pressures and temperatures ranging from 20 to 50 MPa and 313 to 373 K, respectively, without any modifiers. The flow rate of CO2 was maintained at 2.5 mL/min for 330 min extraction time. Solvent flow rate effect was examined for CO2 flow rates from 1.5 to 4.5 mL/min. The extracts were analyzed by high-performance liquid chromatography and UV-visible spectroscopy. The results showed that with optimized operating conditions, the maximum yield of lycopene (1.18 mg of lycopene/g of sample) was obtained at 40 MPa, 373 K, and 2.5 mL of CO2/min. Chromatographic analysis indicated that lycopene was extracted from tomato skin with negligible degradation at the optimum conditions and the amount extracted represented more than 94% of the total carotenoid content of the sample. The solubility of lycopene was modeled by use of the Chrastil equation.

  14. Supercritical Carbon Dioxide-Assisted Process for Well-Dispersed Silicon/Graphene Composite as a Li ion Battery Anode

    Science.gov (United States)

    Lee, Sang Ha; Park, Sengyoen; Kim, Min; Yoon, Dohyeon; Chanthad, Chalathorn; Cho, Misuk; Kim, Jaehoon; Park, Jong Hyeok; Lee, Youngkwan

    2016-01-01

    The silicon (Si)/graphene composite has been touted as one of the most promising anode materials for lithium ion batteries. However, the optimal fabrication method for this composite remains a challenge. Here, we developed a novel method using supercritical carbon dioxide (scCO2) to intercalate Si nanoparticles into graphene nanosheets. Silicon was modified with a thin layer of polyaniline, which assisted the dispersion of graphene sheets by introducing π-π interaction. Using scCO2, well-dispersed Si/graphene composite was successfully obtained in a short time under mild temperature. The composite showed high cycle performance (1,789 mAh/g after 250 cycles) and rate capability (1,690 mAh/g at a current density of 4,000 mA/g). This study provides a new approach for cost-effective and scalable preparation of a Si/graphene composite using scCO2 for a highly stable lithium battery anode material. PMID:27535108

  15. Supercritical Carbon Dioxide-Assisted Process for Well-Dispersed Silicon/Graphene Composite as a Li ion Battery Anode

    Science.gov (United States)

    Lee, Sang Ha; Park, Sengyoen; Kim, Min; Yoon, Dohyeon; Chanthad, Chalathorn; Cho, Misuk; Kim, Jaehoon; Park, Jong Hyeok; Lee, Youngkwan

    2016-08-01

    The silicon (Si)/graphene composite has been touted as one of the most promising anode materials for lithium ion batteries. However, the optimal fabrication method for this composite remains a challenge. Here, we developed a novel method using supercritical carbon dioxide (scCO2) to intercalate Si nanoparticles into graphene nanosheets. Silicon was modified with a thin layer of polyaniline, which assisted the dispersion of graphene sheets by introducing π-π interaction. Using scCO2, well-dispersed Si/graphene composite was successfully obtained in a short time under mild temperature. The composite showed high cycle performance (1,789 mAh/g after 250 cycles) and rate capability (1,690 mAh/g at a current density of 4,000 mA/g). This study provides a new approach for cost-effective and scalable preparation of a Si/graphene composite using scCO2 for a highly stable lithium battery anode material.

  16. Fatty Acid Composition and Antioxidant Activity of Tea (Camellia sinensis L. Seed Oil Extracted by Optimized Supercritical Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Ping Xu

    2011-11-01

    Full Text Available Seeds are another product in addition to leaves (raw materials for teas of tea (Camellia sinensis L. plant. The great increase of tea consumption in recent years raises the challenge of finding commercial applications for tea seeds. In the present study, supercritical carbon dioxide (SC-CO2 extraction edible oil from tea seed was carried out, response surface methodology (RSM was used to optimize processing parameters including time (20–90 min, temperature (35–45 °C and pressure (50–90 MPa. The fatty acid composition and antioxidant activity of the extracted oil was also investigated. The highest yield of oil (29.2 ± 0.6% was obtained under optimal SC-CO2 extraction conditions (45 °C, 89.7 min and 32 MPa, respectively, which was significantly higher (p < 0.05 than that (25.3 ± 1.0% given by Soxhlet extraction. Meanwhile, tea seed oil extracted by SC-CO2 contained approximately 80% unsaturated fatty acids and showed a much stronger scavenging ability on the DPPH radical than that extracted by Soxhlet. SC-CO2 is a promising alternative for efficient extraction of edible oil from tea seed. Moreover, tea seed oil extracted by SC-CO2 is highly edible and has good antioxidant activity, and therefore may play a potential role as a health-promoting food resource in human diets.

  17. Characterization of lecithin isolated from anchovy (Engraulis japonica) residues deoiled by supercritical carbon dioxide and organic solvent extraction.

    Science.gov (United States)

    Lee, Seung-Mi; Asaduzzaman, A K M; Chun, Byung-Soo

    2012-07-01

    Lecithin was isolated and characterized from anchovy (Engraulis japonica) deoiled residues using supercritical carbon dioxide (SC-CO(2)) at a semibatch flow extraction process and an organic solvent (hexane) extraction. SC-CO(2) extraction was carried out to extract oil from anchovy at different temperatures (35 to 45 °C) and pressures (15 to 25 MPa). Extraction yield of oil was influenced by physical properties of SC-CO(2) with temperature and pressure changes. The major phospholipids of anchovy lecithin were quantitatively analyzed by high-performance liquid chromatography. Phosphatidylcholine (PC) (68%± 1.00%) and phosphatidylethanolamine (PE) (29%± 0.50%) were the main phospholipids. Thin layer chromatography was performed to purify the individual phospholipids. The fatty acid compositions of lecithin, PC, and PE were analyzed by gas chromatography. A significant amount of eicosapentaenoic acid and docosahexaenoic acid were present in both phospholipids of PC and PE. Emulsions of lecithin in water were prepared through the use of a homogenizer. Oxidative stability of anchovy lecithin was high in spite of its high concentration of long-chain polyunsaturated fatty acids. Lecithin can be totally metabolized by humans, so is well tolerated by humans and nontoxic when ingested. Lecithin from anchovy contain higher amounts of ω-3 fatty acids especially EPA and DHA, it may have positive outcome to use in food and pharmaceutical industries. © 2012 Institute of Food Technologists®

  18. Stability of niosomes with encapsulated vitamin D3 and ferrous sulfate generated using a novel supercritical carbon dioxide method.

    Science.gov (United States)

    Wagner, Michael E; Spoth, Katherine A; Kourkoutis, Lena F; Rizvi, Syed S H

    2016-12-01

    Niosomes were prepared using a novel supercritical carbon dioxide based method to simultaneously encapsulate ferrous sulfate and vitamin D3 as hydrophilic and hydrophobic cargo, respectively. Vesicle particle size was determined to be bimodal with peak diameters of 1.44 ± 0.16 μm and 7.21 ± 0.64 μm, with the smaller peak comprising 98.8% of the total niosomal volume. Encapsulation efficiency of ferrous sulfate was 25.1 ± 0.2% and encapsulation efficiency of vitamin D3 was 95.9 ± 1.47%. Physical stability of the produced niosomes was assessed throughout a storage period of 21 days. Niosomes showed good physical stability at 20 °C, but storage at 4 °C showed an initial burst release, indicating possible rupture of the niosomal membrane. The Korsmeyer-Peppas equation was used to model the release of ferrous sulfate over time at both storage temperatures.

  19. Comparison of Polymer Networks Synthesized by Conventional Free Radical and RAFT Copolymerization Processes in Supercritical Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Patricia Pérez-Salinas

    2017-05-01

    Full Text Available There is a debate in the literature on whether or not polymer networks synthesized by reversible deactivation radical polymerization (RDRP processes, such as reversible addition-fragmentation radical transfer (RAFT copolymerization of vinyl/divinyl monomers, are less heterogeneous than those synthesized by conventional free radical copolymerization (FRP. In this contribution, the syntheses by FRP and RAFT of hydrogels based on 2-hydroxyethylene methacrylate (HEMA and ethylene glycol dimethacrylate (EGDMA in supercritical carbon dioxide (scCO2, using Krytox 157 FSL as the dispersing agent, and the properties of the materials produced, are compared. The materials were characterized by differential scanning calorimetry (DSC, swelling index (SI, infrared spectroscopy (FTIR and scanning electron microscopy (SEM. Studies on ciprofloxacin loading and release rate from hydrogels were also carried out. The combined results show that the hydrogels synthesized by FRP and RAFT are significantly different, with apparently less heterogeneity present in the materials synthesized by RAFT copolymerization. A ratio of experimental (Mcexp to theoretical (Mctheo molecular weight between crosslinks was established as a quantitative tool to assess the degree of heterogeneity of a polymer network.

  20. Cytotoxic Activity of Kenaf Seed Oils from Supercritical Carbon Dioxide Fluid Extraction towards Human Colorectal Cancer (HT29 Cell Lines

    Directory of Open Access Journals (Sweden)

    Siti Aisyah Abd Ghafar

    2013-01-01

    Full Text Available Kenaf (Hibiscus cannabinus from the family Malvaceae, is a valuable fiber plant native to India and Africa and is currently planted as the fourth commercial crop in Malaysia. Kenaf seed oil contains alpha-linolenic acid, phytosterol such as β-sitosterol, vitamin E, and other antioxidants with chemopreventive properties. Kenaf seeds oil (KSO was from supercritical carbon dioxide extraction fluid (SFE at 9 different permutations of parameters based on range of pressures from 200 to 600 bars and temperature from 40 to 80°C. They were 200/40, 200/60, 200/80, 400/40, 400/60, 400/80, 600/40, 600/60, and 600/80. Extraction from 9 parameters of KSO-SFE was screened for cytotoxicity towards human colorectal cancer cell lines (HT29 and mouse embryonic fibroblast (NIH/3T3 cell lines using MTS assay. KSO-SFE at 600/40 showed the strongest cytotoxicity towards HT29 with IC50 of 200 µg/mL. The IC50 for NIH/3T3 was not detected even at highest concentration employed. Cell cycle analysis showed a significant increase in the accumulation of KSO-SFE-treated cells at sub-G1 phase, indicating the induction of apoptosis by KSO-SFE. Further apoptosis induction was confirmed by Annexin V/PI and AO/PI staining.

  1. Supercritical Synthesis of Biodiesel

    Directory of Open Access Journals (Sweden)

    Michel Vaultier

    2012-07-01

    Full Text Available 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.

  2. 超临界二氧化碳萃取三孢布拉霉中的番茄红素%Supercritical Carbon Dioxide Extraction of Lycopene from Blakeslea trispora

    Institute of Scientific and Technical Information of China (English)

    王世娟; 欧阳华勇

    2011-01-01

    [ Objective ] The purpose of the study was to introduce the new extraction technology of lycopene farom Blakeslea trispora. [ Method ] The lycopene was extracted from B. trispora by supercritical carbon dioxide extraction technology and the influence of extraction time, extraction temperature, extraction pressure and flow rate of carbon dioxide on the extraction rate was studied. [ Result ] After the filtered fermentation broth was pretreated with 95% alcohol, the extraction rate of lycopene was highest when the extraction time was 3 h; its extraction rate was highest when the extraction temperature was 45 ℃ and then its extraction rate was decreasing along with the ascending of temperature; the optimum extraction pressure was 45 MPa and the optimum flow rate of carbon dioxide was 20 L/h. [ Conclusion] The optimum technology for extracting lycopene from B. trispora by supercritical carbon dioxide extraction technology was as follows: the pressure was 45 MPa, the temperature was 45 ℃ and the flow rate of carbon dioxide was 20 L/h. Under this condition, the yield rate of lycopene could reach 76%.%[目的]介绍三孢布拉霉中番茄红素的萃取新工艺.[方法]采用超临界二氧化碳流体萃取技术萃取三孢布拉霉中的番茄红素,研究萃取时间、萃取温度、萃取压力及二氧化碳流量对萃取率的影响.[结果]过滤后的发酵液用95%乙醇预处理后萃取3 h时番茄红素的萃取率最高;萃取温度为45℃时番茄红素的萃取率最高,之后随温度升高番茄红素的萃取率下降;最佳萃取压力为45 MPa;最佳二氧化碳流量为20 L/h.[结论]超临界二氧化碳萃取三孢布拉霉中番茄红素的最佳工艺为:压力45 MPa,温度45℃,二氧化碳流量20L/h,此条件下番茄红素的得率可达76%.

  3. [Research progress on biochar carbon sequestration technology].

    Science.gov (United States)

    Jiang, Zhi-Xiang; Zheng, Hao; Li, Feng-Min; Wang, Zhen-Yu

    2013-08-01

    Biochar is a fine-grained and porous material, which is produced by pyrolyzing biomass under anaerobic or oxygen-limiting condition. Due to the aromatic structure, it is resistant to the biotic and abiotic degradation which makes biochar production a promising carbon sequestration technology, and it has attracted widespread attention. Factors including biochar production, biochar stability in soil and the response of plant growth and soil organic carbon to the biochar addition can influence the carbon sequestration potential of biochar. Through exploring the mechanisms of biochar carbon sequestration, the influence of these factors was studied. Furthermore, the research progress of carbon sequestration potential and its economic viability were examined. Finally, aiming at the knowledge gaps in the influencing factors as well as the relationship between these factors, some further research needs were proposed for better application of biochar in China.

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

    Science.gov (United States)

    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.

  5. Preparation of (Ti, Sn)O2 Nano-Composite Photocatalyst by Supercritical Fluid Dry Combination Technology

    Institute of Scientific and Technical Information of China (English)

    Jingchang ZHANG; Qing LI; Weiliang CAO

    2005-01-01

    A series of TiO2-SnO2 nano-sized composite photo-catalysts containing Sn (9.3%~30.1%) were prepared from TiCl4and SnCl4.5H2O by using sol-gel, supercritical fluid dry and solid-phase reaction (SCFD) combination technology.Characterizations with X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier Transform Infrared Spectroscopy (FTIR) showed that, in addition to anatase type TiO2, a new active phase (Ti, Sn)O2 (with particle size of 2.0~4.3 nm) formed, and there were no SnO2 crystals observed in the range of the doping concentration studied. Photo-catalytic reaction of phenol was used as a model reaction to evaluate the catalytic activities of the obtained catalysts. Compared with pure TiO2 or Ti-Sn catalyst prepared with general sol-gel method, Ti-Sn nanocomposite photo-catalyst thus obtained showed significant improvement in catalytic activity. The photo-catalytic degradation rate of phenol could reach as high as 93.5% after 7 h. The preparation conditions of the new phase (Ti, Sn)O2 were investigated and its catalytic mechanism was proposed. The photo-catalytic particles prepared using SCFD combination technology exhibited small particle size, large surface area and high activity.

  6. Supercritical fluid processing: opportunities for new resist materials and processes

    Science.gov (United States)

    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.

  7. Subcritical and supercritical water oxidation of organic, wet wastes for carbon cycling in regenerative life support systems

    Science.gov (United States)

    Ronsse, Frederik; Lasseur, Christophe; Rebeyre, Pierre; Clauwaert, Peter; Luther, Amanda; Rabaey, Korneel; Zhang, Dong Dong; López Barreiro, Diego; Prins, Wolter; Brilman, Wim

    2016-07-01

    For long-term human spaceflight missions, one of the major requirements is the regenerative life support system which has to be capable of recycling carbon, nutrients and water from both solid and liquid wastes generated by the crew and by the local production of food through living organisms (higher plants, fungi, algae, bacteria, …). The European Space Agency's Life Support System, envisioned by the MELiSSA project, consists of a 5 compartment artificial ecosystem, in which the waste receiving compartment (so-called compartment I or briefly 'CI') is based on thermophilic fermentation. However, as the waste generated by the crew compartment and food production compartment contain typical plant fibres (lignin, cellulose and hemicellulose), these recalcitrant fibres end up largely unaffected in the digestate (sludge) generated in the C-I compartment. Therefore, the C-I compartment has to be supplemented with a so-called fibre degradation unit (in short, FDU) for further oxidation or degradation of said plant fibres. A potential solution to degrading these plant fibres and other recalcitrant organics is their oxidation, by means of subcritical or supercritical water, into reusable CO2 while retaining the nutrients in an organic-free liquid effluent. By taking advantage of the altered physicochemical properties of water above or near its critical point (647 K, 22.1 MPa) - including increased solubility of non-polar compounds and oxygen, ion product and diffusivity - process conditions can be created for rapid oxidation of C into CO2. In this research, the oxidizer is provided as a hydrogen peroxide solution which, at elevated temperature, will dissociated into O2. The purpose of this study is to identify ideal process conditions which (a) ensure complete oxidation of carbon, (b) retaining the nutrients other than C in the liquid effluent and (c) require as little oxidizer as possible. Experiments were conducted on a continuous, tubular heated reactor and on batch

  8. In Situ Infrared Spectroscopic Study of Brucite Carbonation in Dry to Water-Saturated Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Loring, John S.; Thompson, Christopher J.; Zhang, Changyong; Wang, Zheming; Schaef, Herbert T.; Rosso, Kevin M.

    2012-04-25

    In geologic carbon sequestration, while part of the injected carbon dioxide will dissolve into host brine, some will remain as neat to water saturated super critical CO2 (scCO2) near the well bore and at the caprock, especially in the short-term life cycle of the sequestration site. Little is known about the reactivity of minerals with scCO2 containing variable concentrations of water. In this study, we used high-pressure infrared spectroscopy to examine the carbonation of brucite (Mg(OH)2) in situ over a 24 hr reaction period with scCO2 containing water concentrations between 0% and 100% saturation, at temperatures of 35, 50, and 70 °C, and at a pressure of 100 bar. Little or no detectable carbonation was observed when brucite was reacted with neat scCO2. Higher water concentrations and higher temperatures led to greater brucite carbonation rates and larger extents of conversion to magnesium carbonate products. The only observed carbonation product at 35 °C was nesquehonite (MgCO3 • 3H2O). Mixtures of nesquehonite and magnesite (MgCO3) were detected at 50 °C, but magnesite was more prevalent with increasing water concentration. Both an amorphous hydrated magnesium carbonate solid and magnesite were detected at 70 °C, but magnesite predominated with increasing water concentration. The identity of the magnesium carbonate products appears strongly linked to magnesium water exchange kinetics through temperature and water availability effects.

  9. Hydrodynamics and Mass Transfer Performance in Supercritical Fluid Extraction Columns

    Institute of Scientific and Technical Information of China (English)

    石冰洁; 张泽廷; 等

    2002-01-01

    New models for describing hydrodynamics and mass transfer performance in supercritical fluid extraction columns were proposed.Those models were proved by experimental data,which were obtained in supercritical fluid extraction packed column,spray column and sieve tray column respectively.The inner diameter of those columns areΦ25mm,These experimental systems include supercritical carbon dioxideisopropanol-water and supercritical carbon dioxide-ethanol-water,in which supercritical carbon dioxide was dispersed phase,and another was continuous phase.The extraction processes were operated with continuous countercurrent flow.The predicted values are agreed well with experimental data.

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

    Directory of Open Access Journals (Sweden)

    Anne Bernhardt

    Full Text Available 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

  11. Comparison of large scale purification processes of naproxen enantiomers by chromatography using methanol-water and methanol-supercritical carbon dioxide mobile phases.

    Science.gov (United States)

    Kamarei, Fahimeh; Vajda, Péter; Guiochon, Georges

    2013-09-20

    This paper compares two methods used for the preparative purification of a mixture of (S)-, and (R)-naproxen on a Whelk-O1 column, using either high performance liquid chromatography or supercritical fluid chromatography. The adsorption properties of both enantiomers were measured by frontal analysis, using methanol-water and methanol-supercritical carbon dioxide mixtures as the mobile phases. The measured adsorption data were modeled, providing the adsorption isotherms and their parameters, which were derived from the nonlinear fit of the isotherm models to the experimental data points. The model used was a Bi-Langmuir isotherm, similar to the model used in many enantiomeric separations. These isotherms were used to calculate the elution profiles of overloaded elution bands, assuming competitive Bi-Langmuir behavior of the two enantiomers. The analysis of these profiles provides the basis for a comparison between supercritical fluid chromatographic and high performance liquid chromatographic preparative scale separations. It permits an illustration of the advantages and disadvantages of these methods and a discussion of their potential performance.

  12. Comparison of anti-inflammatory activity of extracts with supercritical carbon dioxide from radiation mutant perilla frutescens(L.) Britton and wild-type

    Energy Technology Data Exchange (ETDEWEB)

    Park, Han Chul; So, Yang Kang; Kim, Jin Baek; Jin, Chang Hyun [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Yuk, Hong Sun [Dept. of Food and Nutrition, Chungnam National University Daejeon (Korea, Republic of)

    2016-11-15

    In previous study, the radiation mutant Perilla frutescens (L.) Britton with a higher anti-inflammatory activity was selected. The extracts were obtained from the mutant and wildtype using a supercritical carbon dioxide technique. This study aimed to compare the antiinflammatory activities between the mutant supercritical extract (MSE) and wild-type supercritical extract (WSE). The contents of isoegomaketone (IK) of MSE and WSE were measured through an HPLC analysis. MSE contained IK contents approximately 7-fold higher than those of WSE. To compare the anti-inflammatory activities of MSE and WSE, the expression levels of the mRNA and protein of pro-inflammatory mediators were measured in lipopolysaccharide (LPS)-induced RAW264.7 cells. As a result, MSE inhibited the expression levels of the mRNA and protein of pro-inflammatory mediators, including inducible nitric oxide synthase (iNOS), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and monocyte chemoattractant protein-1 (MCP-1) to a much greater extent than did WSE. Taken together, MSE had more IK contents and higher antiinflammatory activities than WSE. Therefore, MSE is proposed based on its therapeutic potential in the prevention of inflammatory disease.

  13. Tourism Transport, Technology, and Carbon Dioxide Emissions

    NARCIS (Netherlands)

    Peeters, P.M.

    2010-01-01

    Technological development from horse-drawn carriages to the new Airbus A380 has led to a remarkable increase in both the capacity and speed of tourist travel. This development has an endogenous systemic cause and will continue to increase carbon dioxide emissions/energy consumption if left

  14. Tourism Transport, Technology, and Carbon Dioxide Emissions

    NARCIS (Netherlands)

    Peeters, P.M.

    2010-01-01

    Technological development from horse-drawn carriages to the new Airbus A380 has led to a remarkable increase in both the capacity and speed of tourist travel. This development has an endogenous systemic cause and will continue to increase carbon dioxide emissions/energy consumption if left unchecked

  15. Fundamental study of CO2-H2O-mineral interactions for carbon sequestration, with emphasis on the nature of the supercritical fluid-mineral interface.

    Energy Technology Data Exchange (ETDEWEB)

    Bryan, Charles R.; Dewers, Thomas A.; Heath, Jason E.; Wang, Yifeng; Matteo, Edward N.; Meserole, Stephen P.; Tallant, David Robert

    2013-09-01

    In the supercritical CO2-water-mineral systems relevant to subsurface CO2 sequestration, interfacial processes at the supercritical fluid-mineral interface will strongly affect core- and reservoir-scale hydrologic properties. Experimental and theoretical studies have shown that water films will form on mineral surfaces in supercritical CO2, but will be thinner than those that form in vadose zone environments at any given matric potential. The theoretical model presented here allows assessment of water saturation as a function of matric potential, a critical step for evaluating relative permeabilities the CO2 sequestration environment. The experimental water adsorption studies, using Quartz Crystal Microbalance and Fourier Transform Infrared Spectroscopy methods, confirm the major conclusions of the adsorption/condensation model. Additional data provided by the FTIR study is that CO2 intercalation into clays, if it occurs, does not involve carbonate or bicarbonate formation, or significant restriction of CO2 mobility. We have shown that the water film that forms in supercritical CO2 is reactive with common rock-forming minerals, including albite, orthoclase, labradorite, and muscovite. The experimental data indicate that reactivity is a function of water film thickness; at an activity of water of 0.9, the greatest extent of reaction in scCO2 occurred in areas (step edges, surface pits) where capillary condensation thickened the water films. This suggests that dissolution/precipitation reactions may occur preferentially in small pores and pore throats, where it may have a disproportionately large effect on rock hydrologic properties. Finally, a theoretical model is presented here that describes the formation and movement of CO2 ganglia in porous media, allowing assessment of the effect of pore size and structural heterogeneity on capillary trapping efficiency. The model results also suggest possible engineering approaches for optimizing trapping capacity and for

  16. Supercritical Fluid Facilitated Growth of Copper and Aluminum Oxide Nanoparticles

    Science.gov (United States)

    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.

  17. Transient nature of rhizosphere carbon elucidated by supercritical freon-22 extraction and 13C NMR analysis

    Science.gov (United States)

    Filipe G. Sanchez; Maurice M. Bursey

    2002-01-01

    The region immediately adjacent to established roots of mature trees has been termed the "reoccurring rhizosphere" and it has been hypothesized that organic matter input from fine root turnover, root exudates and sloughing may result in a build up of the soil carbon in this region. The "reoccurring rhizosphere" for first-, second- and third-order...

  18. Enzyme-assisted supercritical carbon dioxide extraction of black pepper oleoresin for enhanced yield of piperine-rich extract.

    Science.gov (United States)

    Dutta, Sayantani; Bhattacharjee, Paramita

    2015-07-01

    Black pepper (Piper nigrum L.), the King of Spices is the most popular spice globally and its active ingredient, piperine, is reportedly known for its therapeutic potency. In this work, enzyme-assisted supercritical carbon dioxide (SC-CO2) extraction of black pepper oleoresin was investigated using α-amylase (from Bacillus licheniformis) for enhanced yield of piperine-rich extract possessing good combination of phytochemical properties. Optimization of the extraction parameters (without enzyme), mainly temperature and pressure, was conducted in both batch and continuous modes and the optimized conditions that provided the maximum yield of piperine was in the batch mode, with a sample size of 20 g of black pepper powder (particle diameter 0.42 ± 0.02 mm) at 60 °C and 300 bar at 2 L/min of CO2 flow. Studies on activity of α-amylase were conducted under these optimized conditions in both batch and continuous modes, with varying amounts of lyophilized enzyme (2 mg, 5 mg and 10 mg) and time of exposure of the enzyme to SC-CO2 (2.25 h and 4.25 h). The specific activity of the enzyme increased by 2.13 times when treated in the continuous mode than in the batch mode (1.25 times increase). The structural changes of the treated enzymes were studied by (1)H NMR analyses. In case of α-amylase assisted extractions of black pepper, both batch and continuous modes significantly increased the yields and phytochemical properties of piperine-rich extracts; with higher increase in batch mode than in continuous.

  19. OPTIMISATION OF SUPERCRITICAL FLUID EXTRACTION OF ASTAXANTHIN FROM PENAEUS MONODON WASTE USING ETHANOL-MODIFIED CARBON DIOXIDE

    Directory of Open Access Journals (Sweden)

    SHAZANA A. RADZALI

    2016-05-01

    Full Text Available Some studies demonstrated that astaxanthin surpasses the antioxidant benefits of beta-carotene, zeaxanthin, canthaxanthin, vitamin C, and vitamin E. Penaeus monodon (Tiger shrimp is one of the most valuable traded crustacean products in which astaxanthin can be found in its by-products. The extraction of thermolabile compound like carotenoids at lower temperatures through supercritical carbon dioxide (SC-CO2 can reduce the potential isomerization and degradation of the extraction product. In this study, astaxanthin had been extracted using SC-CO2 with 15% (v/v ethanol as an entrainer and the recovered astaxanthin was analyzed using High performance liquid chromatography (HPLC. A central composite design (CCD was employed to study the effect of three SC-CO2 parameters namely temperature (X1 from 40 to 80°C, pressure (X2 from 150 to 250 bar and extraction flow rate (X3 from 1 to 3 ml/min on the astaxanthin complex yield, (Y1 and free astaxanthin content, (Y2. The nonlinear regression equations were significantly (p0.9261, which had no indication of lack of fit. The results indicated that a combined set of values of temperature (56.88°C, pressure (215.68 bar and extraction flow rate (1.89 ml/min was predicted to provide the optimum region in terms of astaxanthin complex yield, (58.50 ± 2.62 µg/g and free astaxanthin content (12.20 ± 4.16 µg/g studied.

  20. Effect of Supercritical Carbon Dioxide Extraction Parameters on the Biological Activities and Metabolites Present in Extracts from Arthrospira platensis

    Science.gov (United States)

    Esquivel-Hernández, Diego A.; Rodríguez-Rodríguez, José; Cuéllar-Bermúdez, Sara P.; García-Pérez, J. Saúl; Mancera-Andrade, Elena I.; Núñez-Echevarría, Jade E.; Ontiveros-Valencia, Aura; Rostro-Alanis, Magdalena; García-García, Rebeca M.; Torres, J. Antonio; Chen, Wei Ning; Parra-Saldívar, Roberto

    2017-01-01

    Arthrospira platensis was used to obtain functional extracts through supercritical carbon dioxide extraction (SFE-CO2). Pressure (P), temperature (T), co-solvent (CX), static extraction (SX), dispersant (Di) and dynamic extraction (DX) were evaluated as process parameters through a Plackett–Burman design. The maximum extract yield obtained was 7.48 ± 0.15% w/w. The maximum contents of bioactive metabolites in extracts were 0.69 ± 0.09 µg/g of riboflavin, 5.49 ± 0.10 µg/g of α-tocopherol, 524.46 ± 0.10 µg/g of β-carotene, 1.44 ± 0.10 µg/g of lutein and 32.11 ± 0.12 mg/g of fatty acids with 39.38% of palmitic acid, 20.63% of linoleic acid and 30.27% of γ-linolenic acid. A. platensis extracts had an antioxidant activity of 76.47 ± 0.71 µg GAE/g by Folin–Ciocalteu assay, 0.52 ± 0.02, 0.40 ± 0.01 and 1.47 ± 0.02 µmol TE/g by DPPH, FRAP and TEAC assays, respectively. These extracts showed antimicrobial activity against Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922 and Candida albicans ATCC 10231. Overall, co-solvent was the most significant factor for all measured effects (p < 0.05). Arthrospira platensis represents a sustainable source of bioactive compounds through SFE using the following extraction parameters P: 450 bar, CX: 11 g/min, SX: 15 min, DX: 25 min, T: 60 °C and Di: 35 g. PMID:28604646

  1. Organoclay dispersion in linear low-density polyethylene and maleated linear low-density polyethylene via supercritical carbon dioxide processing

    Science.gov (United States)

    Factor, Matthew John

    Research into polymer-clay nanocomposites (PCN’s) has been ongoing for decades as a result of the property enhancements offered by clay. To fully exploit these property enhancements, organically modified clays (organoclays) are utilized to promote clay delamination by reducing the disparity between the hydrophilicity of the clay and the hydrophobicity of the highly used polyolefin polymer. Since the organic modification of organoclays can degrade at temperatures typical to many polymers during melt-mix processing, this work utilizes the low-temperature processing fluid supercritical carbon dioxide (scCO2 ) to disperse an organoclay into the highly used polymer LLDPE and ascertains the associated processing conditions for achieving this goal. Investigations into the LLDPE resin size, scCO2 processing time, scCO2 capability and the processing component compatibility were undertaken to better understand the important parameters to achieving organoclay dispersion, in terms of infusion and intercalation/exfoliation behavior. A LLDPE pellet resin showed improved dispersion and obtainable information over that of a granule resin, securing the choice of resin for subsequent experiments. Experiments undertaken with pellet resin exhibited that a 1-hr processing time was insufficient for organoclay infusion into LLDPE, however when infusion occurs, intercalation/exfoliation can be affected by scCO 2. Increasing the compatibility of LLDPE with clay and the processing fluid revealed that the increased compatibility had altered the effect of scCO2. Further analysis with the 93A-infused samples was conducted in order to gain a better understanding of the effect of scCO2 processing, such as the quantity and size of clay particles dispersed and changes to the polymer incurred by processing.

  2. In vivo antioxidant activity of Pinus koraiensis nut oil obtained by optimised supercritical carbon dioxide extraction.

    Science.gov (United States)

    Chen, Xiaoqiang; Zhang, Ying; Wang, Zhenyu; Zu, Yuangang

    2011-11-01

    In this study, an orthogonal array design OA₉ (3⁴) was employed to optimise the conditions of supercritical carbon dioxide (SC-CO₂) extraction of Pinus koraiensis nut oil. The effects of pressure, temperature and extraction time on the oil yield were investigated. Next, the fatty acid composition of the oil was examined by gas chromatography-mass spectrometry (GC-MS). The in vivo antioxidant activity of the oil was determined by estimating the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), total antioxidant capacity (T-AOC) and the content of malondialdehyde (MDA) in rats fed with a high-fat diet. The results showed that extraction pressure and time were the main variables that influenced the oil yields. The optimal conditions with which to obtain highest yield of oil were determined to be 5760.83 psi, 50°C and 3.0 h (extraction yield was 458.5 g kg⁻¹); nine compounds, constituting about 99.98% of the total oil, were identified. The most abundant polyunsaturated fatty acids identified in the oil, linoleic acid and α-linolenic acid, constituted 41.79% and 15.62% of the oil, respectively. Moreover, the results on their antioxidant activities showed that the oil could improve the activities of SOD, GSH-Px and T-AOC, and reduce the content of MDA significantly, in the serum. These results indicate that P. koraiensis nut oil obtained by SC-CO₂ extraction had excellent antioxidant activities.

  3. Supercritical carbon dioxide extraction of seed oil from winter melon (Benincasa hispida) and its antioxidant activity and fatty acid composition.

    Science.gov (United States)

    Bimakr, Mandana; Rahman, Russly Abdul; Taip, Farah Saleena; Adzahan, Noranizan Mohd; Sarker, Md Zaidul Islam; Ganjloo, Ali

    2013-01-15

    In the present study, supercritical carbon dioxide (SC-CO(2)) extraction of seed oil from winter melon (Benincasa hispida) was investigated. The effects of process variables namely pressure (150-300 bar), temperature (40-50 °C) and dynamic extraction time (60-120 min) on crude extraction yield (CEY) were studied through response surface methodology (RSM). The SC-CO(2) extraction process was modified using ethanol (99.9%) as co-solvent. Perturbation plot revealed the significant effect of all process variables on the CEY. A central composite design (CCD) was used to optimize the process conditions to achieve maximum CEY. The optimum conditions were 244 bar pressure, 46 °C temperature and 97 min dynamic extraction time. Under these optimal conditions, the CEY was predicted to be 176.30 mg-extract/g-dried sample. The validation experiment results agreed with the predicted value. The antioxidant activity and fatty acid composition of crude oil obtained under optimized conditions were determined and compared with published results using Soxhlet extraction (SE) and ultrasound assisted extraction (UAE). It was found that the antioxidant activity of the extract obtained by SC-CO(2) extraction was strongly higher than those obtained by SE and UAE. Identification of fatty acid composition using gas chromatography (GC) showed that all the extracts were rich in unsaturated fatty acids with the most being linoleic acid. In contrast, the amount of saturated fatty acids extracted by SE was higher than that extracted under optimized SC-CO(2) extraction conditions.

  4. Nutritional Quality and Physicochemical Characteristics of Defatted Bovine Liver Treated by Supercritical Carbon Dioxide and Organic Solvent

    Science.gov (United States)

    Kang, Sung-Won; Kim, Hye-Min; Rahman, M. Shafiur; Kim, Ah-Na; Yang, Han-Sul

    2017-01-01

    Defatted bovine liver (DBL) is a potential source of protein and minerals. Supercritical carbon dioxide (SC-CO2) and a traditional organic solvent method were used to remove lipid from bovine liver, and the quality characteristics of a control bovine liver (CBL), bovine liver defatted by SC-CO2 (DBLSC-CO2) at different pressures, and bovine liver defatted by organic solvent (DBL-OS) were compared. The DBLSC-CO2 samples had significantly higher (p<0.05) protein, amino acid, carbohydrate, and fiber contents than CBL and DBL-OS. There was a higher yield of lipid from CBL when using SC-CO2 than the organic solvent method. SDS-PAGE analysis demonstrated that the CBL and DBLSC-CO2 had protein bands of a similar intensity and area, whereas DBL-OS appeared extremely poor bands or no bands due to the degradation of proteins, particularly in the 50 to 75 kDa and 20 to 25 kDa molecular weight ranges. In addition, DBLSC-CO2 was shown to have superior functional properties in terms of total soluble content, water and oil absorption, and foaming and emulsification properties. Therefore, SC-CO2 treatment offers a nutritionally and environmentally friendly approach for the removal of lipid from high protein food sources. In addition, SC-CO2 may be a better substitute of traditional organic solvent extraction for producing more stable and high quality foods with high-protein, fat-free, and low calorie contents. PMID:28316468

  5. Supercritical Carbon Dioxide Extraction of Coronene in the Presence of Perchlorate for In Situ Chemical Analysis of Martian Regolith

    Science.gov (United States)

    McCaig, Heather C.; Stockton, Amanda; Crilly, Candice; Chung, Shirley; Kanik, Isik; Lin, Ying; Zhong, Fang

    2016-09-01

    The analysis of the organic compounds present in the martian regolith is essential for understanding the history and habitability of Mars, as well as studying the signs of possible extant or extinct life. To date, pyrolysis, the only technique that has been used to extract organic compounds from the martian regolith, has not enabled the detection of unaltered native martian organics. The elevated temperatures required for pyrolysis extraction can cause native martian organics to react with perchlorate salts in the regolith and possibly result in the chlorohydrocarbons that have been detected by in situ instruments. Supercritical carbon dioxide (SCCO2) extraction is an alternative to pyrolysis that may be capable of delivering unaltered native organic species to an in situ detector. In this study, we report the SCCO2 extraction of unaltered coronene, a representative polycyclic aromatic hydrocarbon (PAH), from martian regolith simulants, in the presence of 3 parts per thousand (ppth) sodium perchlorate. PAHs are a class of nonpolar molecules of astrobiological interest and are delivered to the martian surface by meteoritic infall. We also determined that the extraction efficiency of coronene was unaffected by the presence of perchlorate on the regolith simulant, and that no sodium perchlorate was extracted by SCCO2. This indicates that SCCO2 extraction can provide de-salted samples that could be directly delivered to a variety of in situ detectors. SCCO2 was also used to extract trace native fluorescent organic compounds from the martian regolith simulant JSC Mars-1, providing further evidence that SCCO2 extraction may provide an alternative to pyrolysis to enable the delivery of unaltered native organic compounds to an in situ detector on a future Mars rover.

  6. Effect of Supercritical Carbon Dioxide Extraction Parameters on the Biological Activities and Metabolites Present in Extracts from Arthrospira platensis

    Directory of Open Access Journals (Sweden)

    Diego A. Esquivel-Hernández

    2017-06-01

    Full Text Available Arthrospira platensis was used to obtain functional extracts through supercritical carbon dioxide extraction (SFE-CO2. Pressure (P, temperature (T, co-solvent (CX, static extraction (SX, dispersant (Di and dynamic extraction (DX were evaluated as process parameters through a Plackett–Burman design. The maximum extract yield obtained was 7.48 ± 0.15% w/w. The maximum contents of bioactive metabolites in extracts were 0.69 ± 0.09 µg/g of riboflavin, 5.49 ± 0.10 µg/g of α-tocopherol, 524.46 ± 0.10 µg/g of β-carotene, 1.44 ± 0.10 µg/g of lutein and 32.11 ± 0.12 mg/g of fatty acids with 39.38% of palmitic acid, 20.63% of linoleic acid and 30.27% of γ-linolenic acid. A. platensis extracts had an antioxidant activity of 76.47 ± 0.71 µg GAE/g by Folin–Ciocalteu assay, 0.52 ± 0.02, 0.40 ± 0.01 and 1.47 ± 0.02 µmol TE/g by DPPH, FRAP and TEAC assays, respectively. These extracts showed antimicrobial activity against Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Escherichia coli ATCC 25922 and Candida albicans ATCC 10231. Overall, co-solvent was the most significant factor for all measured effects (p < 0.05. Arthrospira platensis represents a sustainable source of bioactive compounds through SFE using the following extraction parameters P: 450 bar, CX: 11 g/min, SX: 15 min, DX: 25 min, T: 60 °C and Di: 35 g.

  7. Supercritical Carbon Dioxide Extraction of Seed Oil from Winter Melon (Benincasa hispida and Its Antioxidant Activity and Fatty Acid Composition

    Directory of Open Access Journals (Sweden)

    Ali Ganjloo

    2013-01-01

    Full Text Available In the present study, supercritical carbon dioxide (SC-CO2 extraction of seed oil from winter melon (Benincasa hispida was investigated. The effects of process variables namely pressure (150–300 bar, temperature (40–50 °C and dynamic extraction time (60–120 min on crude extraction yield (CEY were studied through response surface methodology (RSM. The SC-CO2 extraction process was modified using ethanol (99.9% as co-solvent. Perturbation plot revealed the significant effect of all process variables on the CEY. A central composite design (CCD was used to optimize the process conditions to achieve maximum CEY. The optimum conditions were 244 bar pressure, 46 °C temperature and 97 min dynamic extraction time. Under these optimal conditions, the CEY was predicted to be 176.30 mg-extract/g-dried sample. The validation experiment results agreed with the predicted value. The antioxidant activity and fatty acid composition of crude oil obtained under optimized conditions were determined and compared with published results using Soxhlet extraction (SE and ultrasound assisted extraction (UAE. It was found that the antioxidant activity of the extract obtained by SC-CO2 extraction was strongly higher than those obtained by SE and UAE. Identification of fatty acid composition using gas chromatography (GC showed that all the extracts were rich in unsaturated fatty acids with the most being linoleic acid. In contrast, the amount of saturated fatty acids extracted by SE was higher than that extracted under optimized SC-CO2 extraction conditions.

  8. 超临界流体输运技术在缓/控释药物制备中的应用%Applications of Supercritical Fluid Transport Technology in Preparation of Controlled-Release Drug Delivery Systems

    Institute of Scientific and Technical Information of China (English)

    倪敏; 徐琴琴; 徐刚; 王恩俊; 银建中

    2011-01-01

    Among the research of new pharmaceutic dosage forms, controlled-release drug delivery system is a very important issue nowdays. In this field, processes using supercritical fluid technology are mostly " clean" process leading to " clean" products. Meanwhile, inorganic porous materials are emerging as a new category of host/guest systems due to some interesting features such as their biological stability and their drug-releasing properties. This review summarizes the applications of supereritical fluid transport technology in preparation of controlled-release drug delivery system in recent years and pays more attention on the method using supercritical fluid as the solvent and inorganic mesoporous materials as the support to prepare this controlled-release drug delivery system. The technical principle, development of technological process and the main influence factors are discussed here besides the drug release experiments and the comparison with the traditional methods. It shows clearly the advantages and disadvantages of various processes, and sums up the superiority of the supercritical transport technology in preparing controlled-release drug delivery system. Although this technique has lots of advantages, as for the papers delivered at present, the research on supercritical fluid transport technology is just at its initial stage of development because there are so many factors influencing the experimental resuhs and these factors are sometimes link-coupled. It is still challenging to make the preparation controllable. It indicates that the diffusion and penetration of the supercritical carbon dioxide drug solution in porous materials, the surface chemical and physical adsorption mechanism should be focused on as well as the controlled drug release mechanism, thermodynamic model and process dynamic.%缓/控释药物制剂作为一种新药剂是药学研究的热点。本文对近年来超临界流体技术在缓/控释药物系统制备中的研

  9. Optimization and evaluation of foxtail millet (Setaria italica bran oil by supercritical carbon dioxide extraction

    Directory of Open Access Journals (Sweden)

    Pang, M.

    2015-12-01

    Full Text Available A Box-Behnken central composite design combined with the response surface methodology (RSM was used to optimize the parameters of a supercritical fluid extraction (SFE of foxtail millet bran oil (FMBO. Results showed that a maximum oil yield of 7.97% was achieved under the optimal conditions with an extracting pressure of 30.03MPa, extracting temperature of 47.93 °C; and an extraction time of 2.3 h. The quality of the oil obtained from SFE and solvent extraction (SE was evaluated by proximate analysis to include physicochemical properties, fatty acids and sterol compounds. The FBMO obtained from SFE showed a much lower phospholipid (0.188 mg/g content and a preferable color compared to the oil from SE, while it contained a higher content of total sterols, 1.55%. The thermal gravimetric analysis results showed one major regime of weight loss over a temperature range of 300–500 °C. The results show that FBMO obtained by SFE can be a promising nutritional source for food fortification and is understood to have more potentially healthy biological properties.Un diseño Box-Behnken combinado con la metodología de superficie de respuesta (RSM se usó para optimizar los parámetros de extracción mediante fluido supercrítico (SFE de aceite de salvado de mijo (FMBO. Los resultados mostraron que un rendimiento máximo de extracción de aceite del 7,97% se logró en las condiciones óptimas correspondientes a una presión de 30.03MPa, una temperatura 47.93 °C y un tiempo 2,3H. Además, se evaluó la calidad del aceite obtenido por SFE y mediante extracción con disolvente (SE a partir de un análisis proximal que incluye propiedades fisicoquímicas, ácidos grasos y esteroles. El aceite de FBMO obtenido mediante SFE mostró un contenido mucho menor de fosfolípidos (0.188 mg/g y un color mas aceptable que el aceite de la SE, mientras que contenía un mayor contenido de esteroles totales: 1,55%. El resultado del análisis térmico gravimétrico mostr

  10. Capillary pressure-saturation relations for supercritical CO2 and brine in limestone/dolomite sands: implications for geologic carbon sequestration in carbonate reservoirs.

    Science.gov (United States)

    Wang, Shibo; Tokunaga, Tetsu K

    2015-06-16

    In geologic carbon sequestration, capillary pressure (Pc)-saturation (Sw) relations are needed to predict reservoir processes. Capillarity and its hysteresis have been extensively studied in oil-water and gas-water systems, but few measurements have been reported for supercritical (sc) CO2-water. Here, Pc-Sw relations of scCO2 displacing brine (drainage), and brine rewetting (imbibition) were studied to understand CO2 transport and trapping behavior under reservoir conditions. Hysteretic drainage and imbibition Pc-Sw curves were measured in limestone sands at 45 °C under elevated pressures (8.5 and 12.0 MPa) for scCO2-brine, and in limestone and dolomite sands at 23 °C (0.1 MPa) for air-brine using a new computer programmed porous plate apparatus. scCO2-brine drainage and imbibition curves shifted to lower Pc relative to predictions based on interfacial tension, and therefore deviated from capillary scaling predictions for hydrophilic interactions. Fitting universal scaled drainage and imbibition curves show that wettability alteration resulted from scCO2 exposure over the course of months-long experiments. Residual trapping of the nonwetting phases was determined at Pc = 0 during imbibition. Amounts of trapped scCO2 were significantly larger than for those for air, and increased with pressure (depth), initial scCO2 saturation, and time. These results have important implications for scCO2 distribution, trapping, and leakage potential.

  11. Dispersion of Multiwall Carbon Nanotubes in Organic Solvents through Hydrothermal Supercritical Condition

    Directory of Open Access Journals (Sweden)

    Krishnegowda Jagadish

    2015-01-01

    Full Text Available Multiwall carbon nanotube (MWCNT composite materials require careful formulation of processing methods to ultimately realize the desired properties. Until now, controlled dispersion of MWCNT remains a challenge, due to strong van der Waals binding energies associated with the MWCNT aggregates. In the present study, an effort has been made to disperse MWCNTs in organic solvents like dichloromethane, ethanol, isopropyl alcohol, and hexane through hydrothermal reaction. Dichloromethane is considered the best solvent for the dispersion of MWCNTs. The characterizations were carried out to find the dispersion design, particle size, and stabilization, which clearly indicate that the desired properties of MWCNTs have been achieved.

  12. A Review on the Effects of Supercritical Carbon Dioxide on Enzyme Activity

    Directory of Open Access Journals (Sweden)

    Marie Zarevúcka

    2010-01-01

    Full Text Available Different types of enzymes such as lipases, several phosphatases, dehydrogenases, oxidases, amylases and others are well suited for the reactions in SC-CO2. The stability and the activity of enzymes exposed to carbon dioxide under high pressure depend on enzyme species, water content in the solution and on the pressure and temperature of the reaction system. The three-dimensional structure of enzymes may be significantly altered under extreme conditions, causing their denaturation and consequent loss of activity. If the conditions are less adverse, the protein structure may be largely retained. Minor structural changes may induce an alternative active protein state with altered enzyme activity, specificity and stability.

  13. Controlling Foam Morphology of Poly(methyl methacrylate via Surface Chemistry and Concentration of Silica Nanoparticles and Supercritical Carbon Dioxide Process Parameters

    Directory of Open Access Journals (Sweden)

    Deniz Rende

    2013-01-01

    Full Text Available Polymer nanocomposite foams have received considerable attention because of their potential use in advanced applications such as bone scaffolds, food packaging, and transportation materials due to their low density and enhanced mechanical, thermal, and electrical properties compared to traditional polymer foams. In this study, silica nanofillers were used as nucleating agents and supercritical carbon dioxide as the foaming agent. The use of nanofillers provides an interface upon which CO2 nucleates and leads to remarkably low average cell sizes while improving cell density (number of cells per unit volume. In this study, the effect of concentration, the extent of surface modification of silica nanofillers with CO2-philic chemical groups, and supercritical carbon dioxide process conditions on the foam morphology of poly(methyl methacrylate, PMMA, were systematically investigated to shed light on the relative importance of material and process parameters. The silica nanoparticles were chemically modified with tridecafluoro-1,1,2,2-tetrahydrooctyl triethoxysilane leading to three different surface chemistries. The silica concentration was varied from 0.85 to 3.2% (by weight. The supercritical CO2 foaming was performed at four different temperatures (40, 65, 75, and 85°C and between 8.97 and 17.93 MPa. By altering the surface chemistry of the silica nanofiller and manipulating the process conditions, the average cell diameter was decreased from 9.62±5.22 to 1.06±0.32 μm, whereas, the cell density was increased from 7.5±0.5×108 to 4.8±0.3×1011 cells/cm3. Our findings indicate that surface modification of silica nanoparticles with CO2-philic surfactants has the strongest effect on foam morphology.

  14. Recycling technology of emitted carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Arakawa, Hironori [National Inst. of Materials and Chemical Research (NIMC), Ibaraki (Japan)

    1993-12-31

    Ways to halt global warming are being discussed worldwide. Global warming is an energy problem which is mainly attributed to the large volumes of carbon dioxide (CO{sub 2}) released into the atmosphere from the rapid increase in energy consumption since the Industrial Revolution. The basic solution to the problem, therefore, is to cut consumption of fossil fuels. To this end, it is important to promote energy conservation by improving the fuel efficiency of machines, as well as shift to energy sources that do not emit carbon dioxide and develop related technologies. If current trends in economic growth continue in the devloping world as well as the developed countries, there can be no doubt that energy consumption will increase. Therefore, alongside energy conservation and the development of alternative energies, the importance of technologies to recover and fix CO{sub 2} will increase in the fight against global warming.

  15. Experimental Adsorption Isotherm of Methane onto Activated Carbon at Sub- and Supercritical Temperatures

    KAUST Repository

    Rahman, Kazi Afzalur

    2010-11-11

    This paper presents the experimentally measured adsorption isotherm data for methane onto the pitch-based activated carbon type Maxsorb III for temperatures ranging from (120 to 220) K and pressures up to 1.4 MPa. These data are useful to study adsorbed natural gas (ANG) storage systems when the low temperature natural gas regasified from the liquid phase is considered to charge in the storage chamber. Adsorption parameters were evaluated from the isotherm data using the Tóth and Dubinin-Astakhov models. The isosteric heat of adsorption, which is concentration- and temperature-dependent, is extracted from the data. The Henry\\'s law coefficients for the methane/Maxsorb III pairs are evaluated at various temperatures. © 2010 American Chemical Society.

  16. Influence of the reactant carbon-hydrogen-oxygen composition on the key products of the direct gasification of dewatered sewage sludge in supercritical water.

    Science.gov (United States)

    Gong, Miao; Zhu, Wei; Fan, Yujie; Zhang, Huiwen; Su, Ying

    2016-05-01

    The supercritical water gasification of ten different types of dewatered sewage sludges was investigated to understand the relationship between sludge properties and gasification products. Experiments were performed in a high-pressure autoclave at 400°C for 60 min. Results showed that gasification of sewage sludge in supercritical water consists mainly of a gasification reaction, a carbonization reaction and a persistent organic pollutants synthesis reaction. Changes in the reactant C/H/O composition have significant effects on the key gasification products. Total gas production increased with increasing C/H2O of the reactant. The char/coke content increased with increasing C/H ratio of the reactant. A decrease in the C/O ratio of the reactant led to a reduction in polycyclic aromatic hydrocarbon formation. This means that we can adjust the reactant C/H/O composition by adding carbon-, hydrogen-, and oxygen-containing substances such as coal, algae and H2O2 to optimize hydrogen production and to inhibit an undesired by-product formation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Chemical composition and bioactivity of Citrus medica L. cv. Diamante essential oil obtained by hydrodistillation, cold-pressing and supercritical carbon dioxide extraction.

    Science.gov (United States)

    Menichini, Federica; Tundis, Rosa; Bonesi, Marco; de Cindio, Bruno; Loizzo, Monica R; Conforti, Filomena; Statti, Giancarlo A; Menabeni, Roberta; Bettini, Ruggero; Menichini, Francesco

    2011-04-01

    The chemical composition of the essential oil of Citrus medica L. cv. Diamante peel obtained by hydrodistillation, cold-pressing and supercritical carbon dioxide extraction techniques was determined by GC/MS analysis. Forty-six components were fully characterised. Limonene and γ-terpinene were the major components of the oils obtained by hydrodistillation (HD) and cold-pressing (CP), while citropten was the major constituent in the oil obtained by supercritical carbon dioxide extraction (SFE). Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities were evaluated. The essential oil obtained by hydrodistillation exerted the highest inhibitory activity against BChE (IC₅₀ value of 154.6 µg mL⁻¹) and AChE (IC₅₀ value of 171.3 µg mL⁻¹. Interestingly, the oil obtained by cold-pressing exhibited a selective inhibitory activity against AChE. The essential oils have also been evaluated for the inhibition of NO production in LPS induced RAW 264.7 macrophages. The oil obtained by hydrodistillation exerted a significant inhibition of NO production with an IC₅₀ value of 17 µg mL⁻¹ (IC₅₀ of positive control 53 µg mL⁻¹).

  18. Carbon Dioxide Reduction Technology Trade Study

    Science.gov (United States)

    Jeng, Frank F.; Anderson, Molly S.; Abney, Morgan B.

    2011-01-01

    For long-term human missions, a closed-loop atmosphere revitalization system (ARS) is essential to minimize consumables. A carbon dioxide (CO2) reduction technology is used to reclaim oxygen (O2) from metabolic CO2 and is vital to reduce the delivery mass of metabolic O2. A key step in closing the loop for ARS will include a proper CO2 reduction subsystem that is reliable and with low equivalent system mass (ESM). Sabatier and Bosch CO2 reduction are two traditional CO2 reduction subsystems (CRS). Although a Sabatier CRS has been delivered to International Space Station (ISS) and is an important step toward closing the ISS ARS loop, it recovers only 50% of the available O2 in CO2. A Bosch CRS is able to reclaim all O2 in CO2. However, due to continuous carbon deposition on the catalyst surface, the penalties of replacing spent catalysts and reactors and crew time in a Bosch CRS are significant. Recently, technologies have been developed for recovering hydrogen (H2) from Sabatier-product methane (CH4). These include methane pyrolysis using a microwave plasma, catalytic thermal pyrolysis of CH4 and thermal pyrolysis of CH4. Further, development in Sabatier reactor designs based on microchannel and microlith technology could open up opportunities in reducing system mass and enhancing system control. Improvements in Bosch CRS conversion have also been reported. In addition, co-electrolysis of steam and CO2 is a new technology that integrates oxygen generation and CO2 reduction functions in a single system. A co-electrolysis unit followed by either a Sabatier or a carbon formation reactor based on Bosch chemistry could improve the overall competitiveness of an integrated O2 generation and CO2 reduction subsystem. This study evaluates all these CO2 reduction technologies, conducts water mass balances for required external supply of water for 1-, 5- and 10-yr missions, evaluates mass, volume, power, cooling and resupply requirements of various technologies. A system

  19. Corrosion in supercritical fluids

    Energy Technology Data Exchange (ETDEWEB)

    Propp, W.A.; Carleson, T.E.; Wai, Chen M.; Taylor, P.R.; Daehling, K.W.; Huang, Shaoping; Abdel-Latif, M.

    1996-05-01

    Integrated studies were carried out in the areas of corrosion, thermodynamic modeling, and electrochemistry under pressure and temperature conditions appropriate for potential applications of supercritical fluid (SCF) extractive metallurgy. Carbon dioxide and water were the primary fluids studied. Modifiers were used in some tests; these consisted of 1 wt% water and 10 wt% methanol for carbon dioxide and of sulfuric acid, sodium sulfate, ammonium sulfate, and ammonium nitrate at concentrations ranging from 0.00517 to 0.010 M for the aqueous fluids. The materials studied were Types 304 and 316 (UNS S30400 and S31600) stainless steel, iron, and AISI-SAE 1080 (UNS G10800) carbon steel. The thermodynamic modeling consisted of development of a personal computer-based program for generating Pourbaix diagrams at supercritical conditions in aqueous systems. As part of the model, a general method for extrapolating entropies and related thermodynamic properties from ambient to SCF conditions was developed. The experimental work was used as a tool to evaluate the predictions of the model for these systems. The model predicted a general loss of passivation in iron-based alloys at SCF conditions that was consistent with experimentally measured corrosion rates and open circuit potentials. For carbon-dioxide-based SCFs, measured corrosion rates were low, indicating that carbon steel would be suitable for use with unmodified carbon dioxide, while Type 304 stainless steel would be suitable for use with water or methanol as modifiers.

  20. Predicting the supercritical carbon dioxide extraction of oregano bract essential oil

    Directory of Open Access Journals (Sweden)

    Abdolreza Moghadassi

    2011-10-01

    Full Text Available The extraction of essential oils using compressed carbon dioxide is a modern technique offering significant advantagesover more conventional methods, especially in particular applications. The prediction of extraction efficiency is a powerful toolfor designing and optimizing the process. The current work proposed a new method based on the artificial neural network(ANN for the estimation of the extraction efficiency of the essential oil oregano bract. In addition, the work used the backpropagationlearning algorithm, incorporating different training methods. The required data were collected; pre-treating wasused for ANN training. The accuracy and trend stability of the trained networks were verified according to their ability to predictunseen data. The Levenberg-Marquardt algorithm has been found to be the most suitable algorithm, with the appropriatenumber of neurons (i.e., ten neurons in the hidden layer and a minimum average absolute relative error (i.e., 0.019164. Inaddition, some excellent predictions with maximum error of 0.039313 were observed. The results demonstrated the ANN’scapability to predict the measured data. The ANN model performance was also compared to a suitable mathematical model,thereby confirming the superiority of the ANN model.

  1. Method to remove poisonous chlorine compounds using supercritical carbon dioxide. Chorinkai tansan gas wo mochiita yudoku enso kagobutsu no jokyoho

    Energy Technology Data Exchange (ETDEWEB)

    Ikushima, Y. (Government Industrial Research Institute, Tohoku, Sendai (Japan))

    1989-12-15

    This paper describes a method to extract and remove selectively poisonous chlorine compounds from aqueous solution using supercritical CO2. This method is characterized in that it extracts and separates only chlorine compounds in short time under a moderate condition, and removes it without a need of whatever post-treatment. The supercritical CO2 pressure was 80 kg/cm[sup 2], and the extraction temperature was 40[degree]C. The supercritical CO2 extracted 70% to 80% by weight of trichloroethylene and tetrachloroethylene in 15 to 30 minutes, almost all of 1,2-dichloroethane and 1,1,1-trichloroethane in one hour, and about 70% by weight of benzil chloride after 90 minutes. When the supercritical CO2 extraction was carried out for a dilute chlorine compound at 1000 ppm for three hours, the concentrations of trichloroethylene and tetrachloroethylene in the aqueous solution decreased down to several ppm, with no other substances than chlorine compounds detected in the extracts. This proves that no water has been extracted at all. 5 figs., 1 tab.

  2. Novel supercritical carbon dioxide impregnation technique for the production of amorphous solid drug dispersions: a comparison to hot melt extrusion.

    Science.gov (United States)

    Potter, Catherine; Tian, Yiwei; Walker, Gavin; McCoy, Colin; Hornsby, Peter; Donnelly, Conor; Jones, David S; Andrews, Gavin P

    2015-05-04

    The formulation of BCS Class II drugs as amorphous solid dispersions has been shown to provide advantages with respect to improving the aqueous solubility of these compounds. While hot melt extrusion (HME) and spray drying (SD) are among the most common methods for the production of amorphous solid dispersions (ASDs), the high temperatures often required for HME can restrict the processing of thermally labile drugs, while the use of toxic organic solvents during SD can impact on end-product toxicity. In this study, we investigated the potential of supercritical fluid impregnation (SFI) using carbon dioxide as an alternative process for ASD production of a model poorly water-soluble drug, indomethacin (INM). In doing so, we produced ASDs without the use of organic solvents and at temperatures considerably lower than those required for HME. Previous studies have concentrated on the characterization of ASDs produced using HME or SFI but have not considered both processes together. Dispersions were manufactured using two different polymers, Soluplus and polyvinylpyrrolidone K15 using both SFI and HME and characterized for drug morphology, homogeneity, presence of drug-polymer interactions, glass transition temperature, amorphous stability of the drug within the formulation, and nonsink drug release to measure the ability of each formulation to create a supersaturated drug solution. Fully amorphous dispersions were successfully produced at 50% w/w drug loading using HME and 30% w/w drug loading using SFI. For both polymers, formulations containing 50% w/w INM, manufactured via SFI, contained the drug in the γ-crystalline form. Interestingly, there were lower levels of crystallinity in PVP dispersions relative to SOL. FTIR was used to probe for the presence of drug-polymer interactions within both polymer systems. For PVP systems, the nature of these interactions depended upon processing method; however, for Soluplus formulations this was not the case. The area under

  3. In situ study of CO₂ and H₂O partitioning between Na-montmorillonite and variably wet supercritical carbon dioxide.

    Science.gov (United States)

    Loring, John S; Ilton, Eugene S; Chen, Jeffrey; Thompson, Christopher J; Martin, Paul F; Bénézeth, Pascale; Rosso, Kevin M; Felmy, Andrew R; Schaef, Herbert T

    2014-06-03

    Shale formations play fundamental roles in large-scale geologic carbon sequestration (GCS) aimed primarily to mitigate climate change and in smaller-scale GCS targeted mainly for CO2-enhanced gas recovery operations. Reactive components of shales include expandable clays, such as montmorillonites and mixed-layer illite/smectite clays. In this study, in situ X-ray diffraction (XRD) and in situ infrared (IR) spectroscopy were used to investigate the swelling/shrinkage and H2O/CO2 sorption of Na(+)-exchanged montmorillonite, Na-SWy-2, as the clay is exposed to variably hydrated supercritical CO2 (scCO2) at 50 °C and 90 bar. Measured d001 values increased in stepwise fashion and sorbed H2O concentrations increased continuously with increasing percent H2O saturation in scCO2, closely following previously reported values measured in air at ambient pressure over a range of relative humidities. IR spectra show H2O and CO2 intercalation, and variations in peak shapes and positions suggest multiple sorbed types of H2O and CO2 with distinct chemical environments. Based on the absorbance of the asymmetric CO stretching band of the CO2 associated with the Na-SWy-2, the sorbed CO2 concentration increases dramatically at sorbed H2O concentrations from 0 to 4 mmol/g. Sorbed CO2 then sharply decreases as sorbed H2O increases from 4 to 10 mmol/g. With even higher sorbed H2O concentrations as saturation of H2O in scCO2 was approached, the concentration of sorbed CO2 decreased asymptotically. Two models, one involving space filling and the other a heterogeneous distribution of integral hydration states, are discussed as possible mechanisms for H2O and CO2 intercalations in montmorillonite. The swelling/shrinkage of montmorillonite could affect solid volume, porosity, and permeability of shales. Consequently, the results may aid predictions of shale caprock integrity in large-scale GCS as well as methane transmissivity in enhanced gas recovery operations.

  4. A Review of Enzymatic Transesterification of Microalgal Oil-Based Biodiesel Using Supercritical Technology

    Directory of Open Access Journals (Sweden)

    Hanifa Taher

    2011-01-01

    In this paper, conventional biodiesel production with first generation feedstock, using chemical catalysts and solvent-extraction, is compared to new technologies with an emphasis on using microalgae, immobilized lipase, and SC-CO2 as an extraction solvent and reaction media.

  5. Supercritical Carbon Dioxide-Soluble Ligands for Extracting Actinide Metal Ions from Porous Solids

    Energy Technology Data Exchange (ETDEWEB)

    Joan Brennecke; Mark Dietz; Richard Barrans; Alabert Herlinger

    2003-07-03

    Numerous types of actinide-bearing waste materials are found throughout the DOE complex. Most of these wastes consist of large volumes of non-hazardous materials contaminated with relatively small quantities of actinide elements. Separation of these wastes into their inert and radioactive components would dramatically reduce the costs of stabilization and disposal. For example, the DOE is responsible for decontaminating concrete within 7000 surplus contaminated buildings. The best technology now available for removing surface contamination from concrete involves removing the surface layer by grit blasting, which produces a large volume of blasting residue containing a small amount of radioactive material. Disposal of this residue is expensive because of its large volume and fine particulate nature. Considerable cost savings would result from separation of the radioactive constituents and stabilization of the concrete dust. Similarly, gas diffusion plants for uranium enrichment contain valuable high-purity nickel in the form of diffusion barriers. Decontamination is complicated by the extremely fine pores in these barriers, which are not readily accessible by most cleaning techniques. A cost-effect method for the removal of radioactive contaminants would release this valuable material for salvage.

  6. Continuous catalytic hydrogenation of polyaromatic hydrocarbon compounds in hydrogen-supercritical carbon dioxide.

    Science.gov (United States)

    Yuan, Tao; Fournier, Anick R; Proudlock, Raymond; Marshall, William D

    2007-03-15

    A continuous hydrogenation device was evaluated for the detoxification of selected tri-, tetra-, or pentacyclic polyaromatic hydrocarbon (PAH) compounds {anthracene, phenanthrene, chrysene, and benzo[a]pyrene (B[a]P)} by hydrogenation. A substrate stream in hexane, 0.05-1.0% (w/v), was mixed with hydrogen-carbon dioxide (H2-CO2, 5-30% v/v) and delivered to a heated reactor column (25 cm x 1 cm) containing palladium supported on gamma alumina (Pd0/gamma-Al2O3) that was terminated with a capillary restrictor. The flow rate from the reactor, approximately 800 mL min(-1) decompressed gas, corresponded to 4 mL min(-1) fluid under the operating conditions of the trials. Reaction products were recovered by passing the reactor effluent through hexane. At 90 degrees C, the anthracene or phenanthrene substrate was hydrogenated only partially to octahydro and dodecahydro species and contained only a minor quantity of totally hydrogenated products. For substrates with increasing numbers of fused aromatic rings, the hydrogenation efficiency was decreased further. However, at an increasing temperature (90-150 degrees C) and increasing mobile phase flow rate (20.68 MPa corresponding to 2100 mL min(-1) decompressed gas), B[a]P and chrysene were hydrogenated, virtuallytotally, to their corresponding perhydro analogues (eicosahydrobenzo[a]pyrenes and octadecahydrochrysenes), respectively. That this approach might be useful for decontaminating soil extracts was supported by companion in vitro trials in which the substrate and products were assayed for mutagenic activity with five bacterial strains that are auxotrophic for histidine (Salmonella typhimurium TA98, TA100, TA1535, and TA1537) or tryptophan (Escherichia coliWP2 uvrA), using the bacterial reverse mutation assay (modified Ames test). Generally, substantial increases in revertant colony counts were not observed with any of the strains following exposure to the hydrogenation products in the absence or presence of the 10 or 30

  7. In Situ Study of CO2 and H2O Partitioning Between Na-Montmorillonite and Variably Wet Supercritical Carbon Dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Loring, John S.; Ilton, Eugene S.; Chen, Jeffrey; Thompson, Christopher J.; Martin, Paul F.; Benezeth, Pascale; Rosso, Kevin M.; Felmy, Andrew R.; Schaef, Herbert T.

    2014-06-03

    Shale formations play fundamental roles in large-scale geologic carbon sequestration (GCS) aimed primarily to mitigate climate change, and in smaller-scale GCS targeted mainly for CO2-enhanced gas recovery operations. In both technologies, CO2 is injected underground as a supercritical fluid (scCO2), where interactions with shale minerals could influence successful GCS implementation. Reactive components of shales include expandable clays, such as montmorillonites and mixed-layer illite/smectite clays. In this work, we used in situ X-ray diffraction (XRD) and in situ infrared (IR) spectroscopy to investigate the swelling/shrinkage and water/CO2 sorption of a pure montmorillonite, Na-SWy-2, when the clay is exposed to variably hydrated scCO2 at 50 °C and 90 bar. Measured interlayer spacings and sorbed water concentrations at varying levels of scCO2 hydration are similar to previously reported values measured in air at ambient pressure over a range of relative humidities. IR spectra show evidence of both water and CO2 intercalation, and variations in peak shapes and positions suggest multiple sorbed types with distinct chemical environments. Based on the intensity of the asymmetric CO stretching band of the CO2 associated with the Na-SWy-2, we observed a significant increase in sorbed CO2 as the clay expands from a 0W to a 1W state, suggesting that water props open the interlayer so that CO2 can enter. However, as the clay transitions from a 1W to a 2W state, CO2 desorbs sharply. These observations were placed in the context of two conceptual models concerning hydration mechanisms for expandable clays and were also discussed in light of recent theoretical studies on CO2-H2O-clay interactions. The swelling/shrinkage of expandable clays could affect solid volume, porosity, and permeability of shales. Consequently, the results from this work could aid predictions of shale caprock integrity in large-scale GCS, as well as methane transmissivity in enhanced gas recovery

  8. Enhancement of the dissolution rate and bioavailability of fenofibrate by a melt-adsorption method using supercritical carbon dioxide

    Directory of Open Access Journals (Sweden)

    Cha KH

    2012-10-01

    Full Text Available Kwang-Ho Cha,1,3 Kyung-Jin Cho,3 Min-Soo Kim,4 Jeong-Soo Kim,3 Hee Jun Park,1,3 Junsung Park,1,3 Wonkyung Cho,1,3 Jeong-Sook Park,3 Sung-Joo Hwang1,21Yonsei Institute of Pharmaceutical Sciences, 2College of Pharmacy, Yonsei University, Incheon, Republic of Korea; 3College of Pharmacy, Chungnam National University, Daejeon, Republic of Korea; 4Department of Pharmaceutical Engineering, Inje University, Gimhae, Republic of KoreaBackground: The aim of this study was to enhance the bioavailability of fenofibrate, a poorly water-soluble drug, using a melt-adsorption method with supercritical CO2.Methods: Fenofibrate was loaded onto Neusilin® UFL2 at different weight ratios of fenofibrate to Neusilin UFL2 by melt-adsorption using supercritical CO2. For comparison, fenofibrate-loaded Neusilin UFL2 was prepared by solvent evaporation and hot melt-adsorption methods. The fenofibrate formulations prepared were characterized by differential scanning calorimetry, powder x-ray diffractometry, specific surface area, pore size distribution, scanning electron microscopy, and energy-dispersive x-ray spectrometry. In vitro dissolution and in vivo bioavailability were also investigated.Results: Fenofibrate was distributed into the pores of Neusilin UFL2 and showed reduced crystal formation following adsorption. Supercritical CO2 facilitated the introduction of fenofibrate into the pores of Neusilin UFL2. Compared with raw fenofibrate, fenofibrate from the prepared powders showed a significantly increased dissolution rate and better bioavailability. In particular, the area under the drug concentration-time curve and maximal serum concentration of the powders prepared using supercritical CO2 were 4.62-fold and 4.52-fold greater than the corresponding values for raw fenofibrate.Conclusion: The results of this study highlight the usefulness of the melt-adsorption method using supercritical CO2 for improving the bioavailability of fenofibrate.Keywords: fenofibrate

  9. FAW Technology Strategies of Low-Carbon Passenger Car

    Institute of Scientific and Technical Information of China (English)

    Li Jun

    2012-01-01

    Author analyzed the global background of low-carbon technology around the world,a technology & economy analysis model called TOS was developed in the paper,author analyzed technology paths for low-carbon Car in China based on the current technologies available and technologies to he developed in China,3 possible paths are presented based on the analysis,author also explained the FAW BlueWay technology strategies for low carbon cars both for short mid and long term objectives.Author concludes the paper with illustration of powertrain lineup for FAW BlueWay Technologies.

  10. Supercritical-assistant liquid crystal template approach to synthesize mesoporous titania/multiwalled carbon nanotube composites with high visible-light driven photocatalytic performance

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chen; Li, Youji, E-mail: bcclyj@163.com; Xu, Peng; Li, Ming; Huo, Pingxiang

    2014-12-15

    Graphical abstract: We investigate the influence of mesoporous titania content upon the visible-light driven photocatalytic performance of MPT/MWCNTs in phenol degradation. - Highlights: • MPT/MWCNTs were fabricated by liquid-crystal template in supercritical CO{sub 2}. • MPT/MWCNTs show high visible-light driven photoactivity for phenol degradation. • MPT/MWCNTs also show high reusable photoactivity under visible irradiation. • MPT content can control visible-light driven photoactivity of MPT/MWCNTs. • MPT is not easily broken away from from MPT/MWCNT composites. - Abstract: Mesoporous titania (MPT) was deposited onto multiwalled carbon nanotubes (MWCNTs) by deposition of titanium sol containing liquid-crystal template with assistant of supercritical CO{sub 2}. The products were characterized with various analytical techniques to determine their structural, morphological, optical absorption and photocatalytic properties. The results indicate that in photocatalytic degradation of phenol under visible light, the mixtures or composites of MPT and MWCNT show the high efficiency because of synergies between absorbing visible light, releasing electrons and facilitating transfer of charge carriers of MWCNTs and providing activated centers of MPT. Because of the mutual constraint between MPT and MWCNTs on the photocatalytic efficiency, the optimal loading of MPT in MPT/MWCNT-3 for phenol degradation is 48%. Because the intimate contact between MWCNTs and MPT is more beneficial to electron transformation, photoactivity of mixture is lower than that of composites with high reusable performance. The optimum conditions of phenol degradation were obtained.

  11. Solvation structure and dynamics of cis- and trans-1,2 dichloroethene isomers in supercritical carbon dioxide. A molecular dynamics simulation study.

    Science.gov (United States)

    Dellis, Dimitris; Skarmoutsos, Ioannis; Samios, Jannis

    2011-10-27

    Molecular dynamics simulation techniques have been employed to investigate the solvation structure and dynamics in dilute mixtures of cis- and trans-1,2-dichloroethene in supercritical carbon dioxide. The calculations were performed for state points along a near-critical isotherm (1.02 T(c)) over a wide range of densities, using new developed optimized potential models for both isomers. The similarities and differences in the solvation structures around each isomer have been presented and discussed. The local density augmentation and enhancement factors of CO(2) around the isomers have been found significantly larger than the corresponding values for pure supercritical CO(2). The dynamic local density reorganization has been investigated and related to previously proposed relaxation mechanisms. The density dependence of the calculated self-diffusion coefficients has revealed the existence of a plateau in the region of 0.7-1.1 ρ(c), where the local density augmentation exhibits the maximum value. The reorientational dynamics of the C═C bond vector have been also studied, exhibiting significant differences between the two isomers in the case of the second-order Legendre time correlation functions.

  12. Rapid and Green Separation of Mono- and Diesters of Monochloropropanediols by Ultrahigh Performance Supercritical Fluid Chromatography-Mass Spectrometry Using Neat Carbon Dioxide as a Mobile Phase.

    Science.gov (United States)

    Jumaah, Firas; Jędrkiewicz, Renata; Gromadzka, Justyna; Namieśnik, Jacek; Essén, Sofia; Turner, Charlotta; Sandahl, Margareta

    2017-09-20

    This study demonstrates the effect of column selectivity and density of supercritical carbon dioxide (SC-CO2) on the separation of monochloropropanediol (MCPD) esters, known as food toxicants, using SC-CO2 without addition of cosolvent in ultrahigh performance supercritical fluid chromatography-mass spectrometry (UHPSFC-MS). This study shows that over 20 2-monochloropropanediol (2-MCPD) and 3-monochloropropanediol (3-MCPD) mono- and diesters are separated on a 2-picolylamine column in less than 12 min. The presence and position of a hydroxyl group in the structure, the number of unsaturated bonds, and the acyl chain length play a significant role in the separation of MCPD esters. The flow rate, backpressure, and column oven temperature, which affect the density of the mobile phase, were shown to have a substantial impact on retention, efficiency, and selectivity. The developed method was successfully applied for the determination of MCPD esters in refined oils and showed a close to excellent green analysis score using the Analytical Eco-Scale.

  13. Supercritical fluid extraction with carbon nanotubes as a solid collection trap for the analysis of polycyclic aromatic hydrocarbons and their derivatives.

    Science.gov (United States)

    Han, Yehua; Ren, Limin; Xu, Kai; Yang, Fan; Li, Yongfeng; Cheng, Tingting; Kang, Xiaomeng; Xu, Chunming; Shi, Quan

    2015-05-22

    A supercritical fluid extraction (SFE) method with an online solid collection trap has been developed for the quantitative analysis of 16 polycyclic aromatic hydrocarbons (PAHs) and 15 typical PAH derivatives in solid matrix. Compared with liquid trapping and C18 solid-phase trapping, multi-walled carbon nanotubes (CNTs) were proved to be the most efficient trapping sorbent for the collection of PAHs and their nitro-, oxy- and alkyl-derivatives. The proposed extraction-collection procedure was systematically optimized in terms of pressure, temperature, extraction time, trapping materials, supercritical fluid flow rate, co-solvent type, and co-solvent percentage, taking into account the interaction between these variables. The whole extraction process could be completed in 15min followed by GC-MS analysis. Quantitative recoveries of PAHs and their derivatives from spiked soil samples (50ngg(-1)) were obtained in the range of 62.9-111.8% with the precisions (RSD, intra-day) ranged from 1.9% to 13.7%. The developed SFE method with online CNTs trapping followed by GC-MS analysis has been demonstrated to be an efficient way for quantitative analysis of trace-level PAHs and their nitro-, oxy-, and alkyl-derivatives in soil samples.

  14. Basic Engineering Research for D and D of R Reactor Storage Pond Sludge: Electrokinetics, Carbon Dioxide Extraction, and Supercritical Water Oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Michael A. Matthews; David A. Bruce,; Thomas A. Davis; Mark C. Thies; John W. Weidner; Ralph E. White

    2002-04-01

    Large quantities of mixed low level waste (MLLW) that fall under the Toxic Substances Control Act (TSCA) exist and will continue to be generated during D and D operations at DOE sites across the country. The standard process for destruction of MLLW is incineration, which has an uncertain future. The extraction and destruction of PCBs from MLLW was the subject of this research Supercritical Fluid Extraction (SFE) with carbon dioxide with 5% ethanol as cosolvent and Supercritical Waster Oxidation (SCWO) were the processes studied in depth. The solid matrix for experimental extraction studies was Toxi-dry, a commonly used absorbent made from plant material. PCB surrogates were 1.2,4-trichlorobenzene (TCB) and 2-chlorobiphenyl (2CBP). Extraction pressures of 2,000 and 4,000 psi and temperatures of 40 and 80 C were studied. Higher extraction efficiencies were observed with cosolvent and at high temperature, but pressure little effect. SCWO treatment of the treatment of the PCB surrogates resulted in their destruction below detection limits.

  15. Enhanced oral bioavailability of silymarin using liposomes containing a bile salt: preparation by supercritical fluid technology and evaluation in vitro and in vivo.

    Science.gov (United States)

    Yang, Gang; Zhao, Yaping; Zhang, Yongtai; Dang, Beilei; Liu, Ying; Feng, Nianping

    2015-01-01

    The aim of this investigation was to develop a procedure to improve the dissolution and bioavailability of silymarin (SM) by using bile salt-containing liposomes that were prepared by supercritical fluid technology (ie, solution-enhanced dispersion by supercritical fluids [SEDS]). The process for the preparation of SM-loaded liposomes containing a bile salt (SM-Lip-SEDS) was optimized using a central composite design of response surface methodology with the ratio of SM to phospholipids (w/w), flow rate of solution (mL/min), and pressure (MPa) as independent variables. Particle size, entrapment efficiency (EE), and drug loading (DL) were dependent variables for optimization of the process and formulation variables. The particle size, zeta potential, EE, and DL of the optimized SM-Lip-SEDS were 160.5 nm, -62.3 mV, 91.4%, and 4.73%, respectively. Two other methods to produce SM liposomes were compared to the SEDS method. The liposomes obtained by the SEDS method exhibited the highest EE and DL, smallest particle size, and best stability compared to liposomes produced by the thin-film dispersion and reversed-phase evaporation methods. Compared to the SM powder, SM-Lip-SEDS showed increased in vitro drug release. The in vivo AUC(0-t) of SM-Lip-SEDS was 4.8-fold higher than that of the SM powder. These results illustrate that liposomes containing a bile salt can be used to enhance the oral bioavailability of SM and that supercritical fluid technology is suitable for the preparation of liposomes.

  16. U.S. program on materials technology for ultra-supercritical coal power plants

    Science.gov (United States)

    Viswanathan, R.; Henry, J. F.; Tanzosh, J.; Stanko, G.; Shingledecker, J.; Vitalis, B.; Purgert, R.

    2005-06-01

    The efficiency of conventional fossil power plants is a strong function of the steam temperature and pressure. Research to increase both has been pursued worldwide, since the energy crisis in the 1970s. The need to reduce CO2 emissions has recently provided an additional incentive to increase efficiency. More recently, interest has been evinced in advanced combustion technologies utilizing oxygen instead of air for combustion. The main enabling technology in achieving the above goals is the development of stronger high temperature materials. Extensive research-and-development programs have resulted in numerous high-strength alloys for heavy section piping and for tubing needed to build boilers. The study reported on here is aimed at identifying, evaluating, and qualifying the materials needed for the construction of the critical components of coal-fired boilers that are capable of operating with steam at temperatures of 760 °C (1400 °F) and pressures of 35 MPa (5000 psi). The economic viability of such a plant has been explored. Candidate alloys applicable to various ranges of temperatures have been identified. Stress rupture tests have been completed on the base metal and on welds to a number of alloys. Steamside oxidation tests in an autoclave at 650 °C (1200 °F) and 800 °C (1475 °F) have been completed. Fireside corrosion tests have been conducted under conditions simulating those of waterwalls and superheater/reheater tubes. The weldability and fabricability of the alloys have been investigated. The capabilities of various overlay coatings and diffusion coatings have been examined. This article provides a status report on the progress achieved to date on this project.

  17. An experimental investigation of supercritical heat transfer in a three-rod bundle equipped with wire-wrap and grid spacers and cooled by carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Eter, Ahmad, E-mail: eng.eter@yahoo.com; Groeneveld, Dé, E-mail: degroeneveld@gmail.com; Tavoularis, Stavros, E-mail: stavros.tavoularis@uottawa.ca

    2016-07-15

    Highlights: • Heat transfer at supercritical pressures was studied experimentally in a three-rod bundle equipped with wire-wrap spacers or grid spacers. • Heat transfer deterioration occurred near the heated inlet under certain conditions. • Normal heat transfer was generally comparable to that in a tube and the predictions of a correlation. - Abstract: Heat transfer measurements in a three-rod bundle equipped with wire-wrap and grid spacers were obtained at supercritical pressures in the Supercritical University of Ottawa Loop (SCUOL). The tests were performed using carbon dioxide, as a surrogate fluid for water, flowing upwards for wide ranges of conditions, including conditions equivalent to the nominal and near-normal operating conditions of the proposed Canadian Super-Critical Water-Cooled Reactor. The test section contained three heated rods and three unheated rod segments with an outer diameter of 10 mm and a pitch-to-diameter ratio of 1.14; the heated length was 1500 mm. Detailed surface temperature measurements along and around the three heated rods were collected using internally traversed thermocouples. The following ranges of test conditions were covered, with equivalent water conditions given inside parentheses: pressure from 6.6 to 8.36 MPa (19.7–25 MPa); inlet temperature from 11 to 30 °C (330–371 °C); mass flux from 200 to 1175 kg m{sup −2} s{sup −1} (340–1822 kg m{sup −2} s{sup −1}); and wall heat flux from 1 to 175 kW m{sup −2} (11–1847 kW m{sup −2}). For one set of tests, the heated rods were fitted with a 1.3 mm OD wire wrap, having an axial pitch of 200 mm along the entire heated length; for a second set, the heated rods were fitted with grid spacers having a 5.3% flow blockage and located at 500 mm axial intervals. The effects of spacer configuration on heat transfer at supercritical pressures were documented and analyzed. The observed experimental trends were compared to those obtained in a experiment in a heated

  18. Supercritical Phase Equilibria Modeling of Glyceride Mixtures and Carbon Dioxide Using the Group Contribution EoS

    Directory of Open Access Journals (Sweden)

    Tiziana Fornari

    2011-01-01

    Experimental data was obtained in a countercurrent packed extraction column at pressures ranging from 16 to 25 MPa and temperatures from 313 to 368 K. The GC-EoS model was applied in a completely predictive manner to simulate the phase equilibria behavior of the multistage separation process. The chemical analysis of the glyceride mixture allowed a significant simplification of its complex composition and thus, a simple and satisfactory simulation of the supercritical extraction process was achieved.

  19. Production of all trans-beta-carotene by using impinging flow of supercritical carbon dioxide anti-solvent pulverization.

    Science.gov (United States)

    Shen, Yi-Chen; Chng, Lee-Muei; Wang, Yuan-Chuen; Shieh, Chwen-Jen; Lin, Kuo-Li; Hsu, Shih-Lan; Chou, Hong-Nong; Chang, Chieh-Ming J

    2012-12-28

    This work investigated column elution chromatography coupled with supercritical anti-solvent precipitation to produce carotenoid rich microsized particulates from microalgal Dunaliella salina species. The extract contained carotenoids ranging from 61.3 mg/g(salina) to 72.5 mg/g(salina) using ultrasonic stirred ethyl ether or tetrahydrofuran (THF) extraction. When 10 L of ethyl alcohol was employed to elute the THF extract, purity of trans-β-carotene is 823.6 mg/g with a recovery of 86.2%. It was found that the supercritical anti-solvent of THF solution at 160 bar and 318 K produced powdered particulates with a purity of carotenoids above 90%. Subsequently, a central composite response surface design method was used to design supercritical anti-solvent precipitation of carotenoid-rich THF solution. This was accomplished by increasing the pressure from 140 bar to 180 bar and the time from 40 min to 60 min at a feed flow rate of 0.2 mL/min. A CO(2) flow rate of 15 L/min and a temperature of 318 K were also used to determine the effects on purity and recovery of trans-β-carotene. The combined process produced micronized precipitates with a mean particle size ranging from 3.5 μm to 19 μm and the purity of trans-β-carotene attained was 926.8 mg/g with a recovery of 54%.

  20. Supercritical Fluid Technology and Chemical Process Intensification%超临界流体技术与化工过程强化

    Institute of Scientific and Technical Information of China (English)

    张珺; 邵凡

    2011-01-01

    化工过程强化是通过减小设备体积、简化工艺或提高设备生产能力达到提高效率、减少废弃物的排放、降低成本、降低物耗等的目的.与传统方法相比,超临界流体技术作为一种新兴的技术提高了效率、简化了工艺、节约了材料、无二次污染,达到了过程强化的目的.介绍了超临界流体技术的优势,从而得到过程强化的效果.%Chemical process intensification can increase efficiency, reduce waste discharge, reduce cost and reduce material consumptions by reducing equipment volume, simplifying process and improving equipment production capacity. Compared with traditional method, supercritical fluid technology as a new technique can improve efficiency, simplify process, save materials and eliminate secondary pollution to reach the purpose of process intensification. In this paper, advantages of supercritical fluid technology was introduced, and effect of process intensification was discussed.