The Experts below are selected from a list of 753 Experts worldwide ranked by ideXlab platform

Yao Ziwei - One of the best experts on this subject based on the ideXlab platform.

  • Development of Cryogenic chromatography using thermoelectric modules for the Separation of methyltin compounds
    IEEE Journal of Solid-state Circuits, 2003
    Co-Authors: Liu Jiemin, Liu Jingfu, Zhou Qunfang, Jiang Guibin, Yao Ziwei
    Abstract:

    A nonliquid Cryogenic gas chromatograph using thermoelectric modules for the Cryogenic Separation of low boiling-point compounds was developed. The new system included four thermoelectric modules, a U shape heat exchanger, a cold block, a temperature controller, and three aluminum sheets. The minimum operating temperature of the assembly was -10degreesC. This thermoelectric system was used to directly cool the capillary column, without any need for a traditional cryogen and had a small volume. The system was cost-effective and convenient to operate. It was successfully applied to the Separation of methyltin species.

  • Development of Cryogenic chromatography using thermoelectric modules for the Separation of methyltin compounds
    Journal of Separation Science, 2003
    Co-Authors: Liu Jiemin, Liu Jingfu, Zhou Qunfang, Jiang Guibin, Yao Ziwei
    Abstract:

    A nonliquid Cryogenic gas chromatograph using thermoelectric modules for the Cryogenic Separation of low boiling-point compounds was developed. The new system included four thermoelectric modules, a U shape heat exchanger, a cold block, a temperature controller, and three aluminum sheets. The minimum operating temperature of the assembly was -10°C. This thermoelectric system was used to directly cool the capillary column, without any need for a traditional cryogen and had a small volume. The system was cost-effective and convenient to operate. It was successfully applied to the Separation of methyltin species.

E. H. Dulf - One of the best experts on this subject based on the ideXlab platform.

  • Tracking and Disturbance Rejection in the 13C Cryogenic Separation Column
    Journal of Control Engineering and Applied Informatics, 2012
    Co-Authors: Cl. Festila, E. H. Dulf, M. Gligan
    Abstract:

    The Separation of carbon isotopes represents a major research area due to the numerous uses of the least abundant carbon isotope, 13C. One of the methods used for separating these isotopes is the Cryogenic distillation, in large counter-current columns. Such industrial plants represent a difficult problem in terms of automatic control, since they are characterized by nonlinearities, delay times and extremely severe control input constraints. The paper presents a simplified nonlinear model of the isotope Separation process as well as the control strategy for tracking and disturbance rejection. The tracking problem is solved based on a multi-loop design with a modified feedback linearization technique as an inner loop controller and an outer robust controller. The disturbance rejection solution consists of a new feed-forward compensator, derived from the classical approach used in feedback linearization techniques. The resulting control strategy achieves robust stability and robust performance for a certain amount of model uncertainties.

  • SACI - Predictive control of the multivariable time delay processes in an isotope Separation column
    2011 6th IEEE International Symposium on Applied Computational Intelligence and Informatics (SACI), 2011
    Co-Authors: E. H. Dulf, Bogdan Muresan, R. De Keyser, Clara M. Ionescu, Cl. Festila
    Abstract:

    The secondary processes in a pilot plant carbon isotope Cryogenic Separation column are multivariable time delay processes. In general, for these types of processes, Smith Predictor control schemes are frequently used, however they exhibit poor robustness due to the explicit use of the process model in the compensation loop and require additional control techniques to enhance robustness against modeling uncertainties. An alternative solution used in this paper is a predictive controller, with intrinsic time delay compensation. The simulations presented show that the predictive controller is also robust to significant time delay estimation errors, without further need to design additional filters for increasing robustness.

  • optimal control of the carbon isotopes Cryogenic Separation process
    Chemical and Biochemical Engineering Quarterly, 2010
    Co-Authors: Cl. Festila, E. H. Dulf
    Abstract:

    The most important demand in an efficient carbon isotope Separation is to keep the Cryogenic distillation column parameters at their required set points, despite disturbances or uncertainties. One of the key parameters is the column temperature that has a direct influence on the carbon Separation coefficient. The nonlinear model of the Separation process considers the top and bottom column temperature evolution and their influence on the isotope Separation rate. The optimal controller designed in this paper effectively maintains the column temperature at constant levels, rejecting disturbances, for a significant range of model uncertainties.

  • Fractional order models for a Cryogenic Separation column
    2010 IEEE International Conference on Automation Quality and Testing Robotics (AQTR), 2010
    Co-Authors: E. H. Dulf, R. Both, D. C. Dumitrache
    Abstract:

    The chemical processes developed in the 13C-isotope Separation plant are very complex and many details are not yet known in totality. The authors are concerned with the problem of developing effective and readily useful techniques for modeling and control of the isotope Separation plant. In the present paper is presented a variant of continuous linear model. Recent studies show that fractional control methods are widely used and that non integer models describe completely the distributed system's behavior. Based on these studies the authors propose two fractional models of the isotope Separation plant. The results are validated and compared by simulation, based on experimental data.

  • Feedback linearization control design for the 13C Cryogenic Separation column
    2010 IEEE International Conference on Automation Quality and Testing Robotics (AQTR), 2010
    Co-Authors: Cl. Festila, E. H. Dulf, Bogdan Muresan
    Abstract:

    The Separation of carbon isotopes represents a major research area due to the numerous uses of the least abundant carbon isotope, 13C. One of the methods used for separating these isotopes is the Cryogenic distillation, in large counter- current columns. Such industrial plants represent a difficult problem in terms of automatic control, since they are characterized by nonlinearities, large delay times and extremely severe control input constraints. The paper presents a control strategy based on a feedback linearization technique as an inner loop controller and a robust controller as the outer loop. The two are combined to result in a nonlinear robust control that achieves robust stability and robust performance for a certain amount of model uncertainties.

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

  • Development of Cryogenic chromatography using thermoelectric modules for the Separation of methyltin compounds
    IEEE Journal of Solid-state Circuits, 2003
    Co-Authors: Liu Jiemin, Liu Jingfu, Zhou Qunfang, Jiang Guibin, Yao Ziwei
    Abstract:

    A nonliquid Cryogenic gas chromatograph using thermoelectric modules for the Cryogenic Separation of low boiling-point compounds was developed. The new system included four thermoelectric modules, a U shape heat exchanger, a cold block, a temperature controller, and three aluminum sheets. The minimum operating temperature of the assembly was -10degreesC. This thermoelectric system was used to directly cool the capillary column, without any need for a traditional cryogen and had a small volume. The system was cost-effective and convenient to operate. It was successfully applied to the Separation of methyltin species.

  • Development of Cryogenic chromatography using thermoelectric modules for the Separation of methyltin compounds
    Journal of Separation Science, 2003
    Co-Authors: Liu Jiemin, Liu Jingfu, Zhou Qunfang, Jiang Guibin, Yao Ziwei
    Abstract:

    A nonliquid Cryogenic gas chromatograph using thermoelectric modules for the Cryogenic Separation of low boiling-point compounds was developed. The new system included four thermoelectric modules, a U shape heat exchanger, a cold block, a temperature controller, and three aluminum sheets. The minimum operating temperature of the assembly was -10°C. This thermoelectric system was used to directly cool the capillary column, without any need for a traditional cryogen and had a small volume. The system was cost-effective and convenient to operate. It was successfully applied to the Separation of methyltin species.

T. R. Reina - One of the best experts on this subject based on the ideXlab platform.

  • Membrane-based technologies for biogas upgrading: a review
    Environmental Chemistry Letters, 2020
    Co-Authors: Francisco M. Baena-moreno, Estelle Saché, Laura Pastor-pérez, T. R. Reina
    Abstract:

    Global warming caused by increasing CO_2 atmospheric levels is calling for sustainable fuels. For instance, biomethane produced by biogas upgrading is a promising source of green energy. Technologies to upgrade biogas include chemical absorption, water scrubbing, physical absorption, adsorption, Cryogenic Separation and membrane Separation. Historically, water scrubbing was preferred because of the simplicity of this operation. However, during the last decade, membrane Separation stood out due to its promising economic viability with investment costs of 3500–7500 €/(m^3/h) and operational costs of 7.5–12.5 €/(m^3/h). Here we review biogas upgrading by membrane Separation. We discuss gas permeation, membrane materials, membrane modules, process configurations and commercial biogas plants. Polymeric materials appear as most adequate for membranes aimed to upgrade biogas. Concerning membrane modules, hollow fibers are the cheapest (1.5–9 €/m^2). Multistage configurations provide high methane recovery, of 99%, and purity, of 95–99%, compared to single-stage configurations.

Cl. Festila - One of the best experts on this subject based on the ideXlab platform.

  • Predictive control of the multivariable time delay processes in an isotope Separation column
    2011 6th IEEE International Symposium on Applied Computational Intelligence and Informatics (SACI), 2011
    Co-Authors: E. H. Dulf, R. De Keyser, C. Ionescu, B. Muresan, Cl. Festila
    Abstract:

    The secondary processes in a pilot plant carbon isotope Cryogenic Separation column are multivariable time delay processes. In general, for these types of processes, Smith Predictor control schemes are frequently used, however they exhibit poor robustness due to the explicit use of the process model in the compensation loop and require additional control techniques to enhance robustness against modeling uncertainties. An alternative solution used in this paper is a predictive controller, with intrinsic time delay compensation. The simulations presented show that the predictive controller is also robust to significant time delay estimation errors, without further need to design additional filters for increasing robustness.

  • SACI - Predictive control of the multivariable time delay processes in an isotope Separation column
    2011 6th IEEE International Symposium on Applied Computational Intelligence and Informatics (SACI), 2011
    Co-Authors: E. H. Dulf, Bogdan Muresan, R. De Keyser, Clara M. Ionescu, Cl. Festila
    Abstract:

    The secondary processes in a pilot plant carbon isotope Cryogenic Separation column are multivariable time delay processes. In general, for these types of processes, Smith Predictor control schemes are frequently used, however they exhibit poor robustness due to the explicit use of the process model in the compensation loop and require additional control techniques to enhance robustness against modeling uncertainties. An alternative solution used in this paper is a predictive controller, with intrinsic time delay compensation. The simulations presented show that the predictive controller is also robust to significant time delay estimation errors, without further need to design additional filters for increasing robustness.

  • Level and pressure control in condenser of the 13C isotope Separation column
    2010 IEEE International Conference on Automation Quality and Testing Robotics (AQTR), 2010
    Co-Authors: Cl. Festila, E. H. Dulf, A. Baldea
    Abstract:

    The process of the 13C in Cryogenic Separation column is an intricate one. A lot of parameters must be kept constant at empirical values. From among these, the nitrogen level and the temperature in condenser are essential for the Separation process. In present, the liquid nitrogen level is controlled manually and any error of the operators can waste the final product. The paper proposes not only a system for liquid nitrogen level control, but also a second system able to decrease - due to the under-pressure - the evaporation temperature of liquid nitrogen in order to improve the Separation process. The paper analyzes the two systems as independent entities and the interinfluences are treated as disturbances. The analysis in the true MIMO frame is a future task.

  • Level and pressure control in condenser of the 13 C isotope Separation column
    2010 IEEE International Conference on Automation Quality and Testing Robotics (AQTR), 2010
    Co-Authors: Cl. Festila, E. H. Dulf, A. Baldea
    Abstract:

    The process of the 13C in Cryogenic Separation column is an intricate one. A lot of parameters must be kept constant at empirical values. From among these, the nitrogen level and the temperature in condenser are essential for the Separation process. In present, the liquid nitrogen level is controlled manually and any error of the operators can waste the final product. The paper proposes not only a system for liquid nitrogen level control, but also a second system able to decrease — due to the under-pressure — the evaporation temperature of liquid nitrogen in order to improve the Separation process. The paper analyzes the two systems as independent entities and the interinfluences are treated as disturbances. The analysis in the true MIMO frame is a future task.