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Geert-jan Witkamp - One of the best experts on this subject based on the ideXlab platform.

  • Kinetics study of a dichlorotriazine reactive dye in Supercritical Carbon Dioxide
    The Journal of Supercritical Fluids, 2004
    Co-Authors: M. V. Fernandez Cid, GREERT FEYE WOERLEE, M. Van Der Kraan, W. J T Veugelers, Geert-jan Witkamp
    Abstract:

    The kinetics of the reaction between a dichlorotriazine reactive dye and methanol was studied in Supercritical Carbon Dioxide and in a solution of pure methanol. The experiments were carried out in a batch reactor at different temperatures between 333 and 393K and at 300bar when Supercritical Carbon Dioxide was the solvent medium. The rate constants and the parameters of the Arrhenius equation were determined and compared. A significant influence of the Supercritical Carbon Dioxide on the rate constants was found. The formation of methoxy-dye was faster over the whole temperature range in pure methanol than in Supercritical Carbon Dioxide. But the consecutive reaction, the formation of dimethoxy-dye, was considerably faster, up to 20 times, in Supercritical Carbon Dioxide than in pure methanol. Moreover, the lowest value for the activation energy, 50 ± 13kJmol−1, was found for the consecutive reaction in Supercritical Carbon Dioxide. In this paper new kinetic data for the methanolysis reaction of a dichlorotriazine reactive dye in Supercritical Carbon Dioxide are shown.

Liu Jun-cheng - One of the best experts on this subject based on the ideXlab platform.

  • Study on solubility of benzoic acid in Supercritical Carbon Dioxide with cosolvent
    Modern Chemical Industry, 2003
    Co-Authors: Liu Jun-cheng
    Abstract:

    The solubility of benzole acid in Supercritical Carbon Dioxide with ethanol, propanol, butanol and pentanol as co-solvent were measured respectively over 10.0 - 30.0 MPa and 35℃ and 50℃ . Results show that the cosolvent of ethanol, propanol, butanol and pentanol added into the Supercritical Carbon Dioxide can distinctly enhance the solubility of benzoic acid, and the enhancement will slightly weaken as the increase of Carbonic atomicity of the cosolvent. The effects of temperture and pressure on the solubility were also discussed, and the measured mole fractions of benzoic acid in Supercritical Carbon Dioxide were correlated with the model presented by Sovova equation.

  • The progress of study and application of Supercritical Carbon Dioxide microemulsion
    China Surfactant Detergent & Cosmetics, 2002
    Co-Authors: Liu Jun-cheng
    Abstract:

    The structure properties of surfactants,which can form Supercritical Carbon Dioxide microemulsions and the effect of cosurfactant on the formation of Supercritical Carbon Dioxide microemulsion are reviewed.Meanwhile,the application of current method of determination such as ultraviovisiblc absorbancc spcctroscopy,fouricr-transform infrarcd spcctroscopy,small-anglc ncutron scattcring and smallangle x-ray scattering to the study of formation and structure properties of Supercritical Carbon Dioxide microemulsion are introduced.Moreover,the application of Supercritical Carbon Dioxide microemulsions to the field of chemical reaction,extraction of biochemicals and metal ions,synthesis of materials and cleaning are also introduccd.

Weiqiang Song - One of the best experts on this subject based on the ideXlab platform.

  • Experimental Study on the Permeability Change of Sandstone Under Supercritical Carbon Dioxide Jet
    Journal of The Institution of Engineers : Series A, 2018
    Co-Authors: Weiqiang Song
    Abstract:

    The technology of drilling and completion with Supercritical Carbon Dioxide possesses broad prospects in unconventional oil and gas reservoir, such as in tight sandstone gas exploitation. The changing method of sandstone permeability under Supercritical Carbon Dioxide jet is highly related with the oil and gas recovery. Based on actual drilling and completion process, and with consideration of changing properties of Supercritical Carbon Dioxide, experiment was designed and conducted to test the changing method of sandstone permeability under Supercritical Carbon Dioxide jet with different jet parameters. The result shows: (1) when the jet pressure, jet temperature and the temperature of sandstone increases respectively, the permeability of sandstone would increase overall; (2) the permeability of sandstone increases firstly, then become a constant value with the growth of jet time. The present work provides experimental and theoretical basis for enhancing oil recovery in the field of Supercritical Carbon Dioxide drilling and completion.

  • wellbore collapse pressure analysis under Supercritical Carbon Dioxide drilling condition
    Journal of Petroleum Science and Engineering, 2018
    Co-Authors: Lu Ding, Hongjian Ni, M Li, Wentuo Li, Weiqiang Song
    Abstract:

    Abstract Compared with the conventional drilling methods, Supercritical Carbon Dioxide used in drilling and completion has considerable potentials and many advantages. However, it is found in the research and practice that there are yet many basic problems to be solved. Wellbore stability is one of them. Firstly, in this paper, on the basis of Span & Wagner equation, combined with unique physical properties of Supercritical Carbon Dioxide, parameters such as temperature and pressure in the wellbore while the Supercritical Carbon Dioxide drilling are calculated. Secondly, the heat and mass transfer effect between the Supercritical Carbon Dioxide and the formation has been studied, and the temperature change near the wellbore formation and stress change near the wellbore have been obtained. Thus, pore pressure change near the wellbore has been obtained. When the depth reaches 1500 m, the downhole temperature will be 12 K lower than the wellbore temperature, and the pore pressure will increase to 20 Mpa as the Supercritical Carbon Dioxide seeps into the formation. Thirdly, mechanical properties change rules when rocks are soaked in the Supercritical Carbon Dioxide are obtained through experiments. The compressive strength decreases by 64%, the elastic modulus increases by 153%, and the poisson ratio decreases by 8%. Based on the above research, the wellbore collapse pressure model has been established. It is revealed that the wellbore collapse pressure rises from 9.17 Mpa to 16.26 MPa with the increase of time, which is still lower than the bottom pressure and cannot lead to instability. Meanwhile, the bottom collapse failure index keeps positive and increases gradually with the increase of time. It means that there is no wellbore enlargement. Therefore, the results have verified the wellbore stability while the Supercritical Carbon Dioxide drilling. It has laid a solid foundation for the future development of Supercritical Carbon Dioxide drilling.

Kinya Sakanishi - One of the best experts on this subject based on the ideXlab platform.

  • Extraction of iron and calcium from low rank coal by Supercritical Carbon Dioxide with entrainers
    Journal of Supercritical Fluids, 2007
    Co-Authors: Yoshio Iwai, Yasuhiko Arai, Natsuki Okamoto, Shinpei Ohta, Kinya Sakanishi
    Abstract:

    Abstract Iron and calcium were extracted from low rank coal with Supercritical Carbon Dioxide and methanol, ethanol, acetic acid, acetyl acetone, ethanol and acetic acid, or acetyl acetone and water entrainers at 313.2 K and 15.0 MPa. The low rank coal used in this study was Berau coal from Indonesia. The addition of methanol, ethanol, or acetic acid entrainers in Supercritical Carbon Dioxide showed very limited effect on enhancement of the recovery rates of Fe. The recovery rates of Fe from dried coal by Supercritical Carbon Dioxide with acetyl acetone were low, however, the addition of acetyl acetone with water in Supercritical Carbon Dioxide remarkably enhanced the recovery rates of Fe. Water seems to play an important role in extracting Fe from coal with Supercritical Carbon Dioxide and acetyl acetone. On the other hand, the extraction rates of Ca with Supercritical Carbon Dioxide and water, methanol, ethanol, and acetyl acetone entrainers were very low. The addition of acetic acid with or without water in Supercritical Carbon Dioxide slightly enhanced the recovery rates of Ca. The addition of acetic acid with ethanol in Supercritical Carbon Dioxide remarkably enhanced the recovery rates of Ca. The effect of Carbon Dioxide flow rate and coal particle size on the recovery rates of Fe were examined. The recovery rate of Fe increased with increasing Carbon Dioxide flow rate and with decreasing particle size of the low rank coal.

  • Low temperature drying of low rank coal by Supercritical Carbon Dioxide with methanol as entrainer
    Journal of Supercritical Fluids, 2002
    Co-Authors: Yoshio Iwai, Yasutake Koujina, Yasuhiko Arai, Izumi Watanabe, Isao Mochida, Kinya Sakanishi
    Abstract:

    Abstract Berau coal as lignite was dried with Supercritical Carbon Dioxide. When methanol was added in Supercritical Carbon Dioxide as an entrainer, the extraction rate of water remarkably increased. Methanol added as an entrainer can reduce water contents to half of those of the coal dried with Supercritical Carbon Dioxide and thermally dried coal. The surface area and pore volume of coal slightly decreased with increase in the mole fraction of methanol added in Supercritical Carbon Dioxide. Flash pyrolysis was carried out at 740 °C for 5 s. The tar yield was significantly larger and the char yield was smaller for the coal dried with Supercritical Carbon Dioxide+methanol compared with those dried with Supercritical Carbon Dioxide only and dried thermally.

  • Physical properties of low rank coals dried with Supercritical Carbon Dioxide
    Journal of Supercritical Fluids, 2000
    Co-Authors: Yoshio Iwai, Tadaaki Murozono, Yasutake Koujina, Yasuhiko Arai, Kinya Sakanishi
    Abstract:

    Abstract Three coal samples from low rank coals (Berau and Taiheiyo) were prepared, such as raw coals, dried coals with Supercritical Carbon Dioxide, and thermally dried coals at 110°C. The physical properties of three samples were analysed by a FT-IR spectroscopy, BET surface area measurement, and solvent swelling with pyridine and methanol. The FT-IR spectra of Berau and Taiheiyo coals showed that the infrared absorption for the thermally dried coals was slightly different from those of the raw coals and coals dried with Supercritical Carbon Dioxide. The surface areas of Berau and Taiheiyo coals dried with Supercritical Carbon Dioxide were larger than thermally dried coals. The changes of structures in the coals may be minimized by drying with Supercritical Carbon Dioxide especially at higher pressures. From the swelling experiments with pyridine, the swelling ratio of Berau coal dried with Supercritical Carbon Dioxide was the highest and that of the thermally dried coal was the lowest among the samples. The swelling results of Taiheiyo coal showed almost the same tendency as those of Berau coal. This indicates that the swellability of low rank coals is enhanced by drying with Supercritical Carbon Dioxide.

M. V. Fernandez Cid - One of the best experts on this subject based on the ideXlab platform.

  • Kinetics study of a dichlorotriazine reactive dye in Supercritical Carbon Dioxide
    The Journal of Supercritical Fluids, 2004
    Co-Authors: M. V. Fernandez Cid, GREERT FEYE WOERLEE, M. Van Der Kraan, W. J T Veugelers, Geert-jan Witkamp
    Abstract:

    The kinetics of the reaction between a dichlorotriazine reactive dye and methanol was studied in Supercritical Carbon Dioxide and in a solution of pure methanol. The experiments were carried out in a batch reactor at different temperatures between 333 and 393K and at 300bar when Supercritical Carbon Dioxide was the solvent medium. The rate constants and the parameters of the Arrhenius equation were determined and compared. A significant influence of the Supercritical Carbon Dioxide on the rate constants was found. The formation of methoxy-dye was faster over the whole temperature range in pure methanol than in Supercritical Carbon Dioxide. But the consecutive reaction, the formation of dimethoxy-dye, was considerably faster, up to 20 times, in Supercritical Carbon Dioxide than in pure methanol. Moreover, the lowest value for the activation energy, 50 ± 13kJmol−1, was found for the consecutive reaction in Supercritical Carbon Dioxide. In this paper new kinetic data for the methanolysis reaction of a dichlorotriazine reactive dye in Supercritical Carbon Dioxide are shown.