The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform

Joshua S. Dranoff - One of the best experts on this subject based on the ideXlab platform.

  • Modeling the thermal cracking of ethane and propane in a non-isothermal vertical Pneumatic Transport reactor
    Industrial & Engineering Chemistry Research, 1992
    Co-Authors: Hiroki Koyama, Joshua S. Dranoff
    Abstract:

    A model has been formulated for noncatalytic thermal cracking of ethane and propane in a non-isothermal, adiabatic, vertical, Pneumatic Transport reactor. This model takes into consideration hydrodynamic properties of the gas-solid mixture, gas-particle heat transfer, and a kinetic scheme involving 81 radical reactions among 11 molecules and 11 radicals. Simulations of ethane cracking at a fixed conversion show that the particle diameter and solid to hydrocarbon ratio have the greatest effect on reactor performance; an optimum particle diameter of 50 μm was found

J.m. Beeckmans - One of the best experts on this subject based on the ideXlab platform.

  • pressure gradient and particle adhesion in the Pneumatic Transport of cohesive fine powders
    International Journal of Multiphase Flow, 2000
    Co-Authors: F Wang, Jesse Zhu, J.m. Beeckmans
    Abstract:

    Pneumatic Transport of Group C 20 μm glass beads was studied in a 31.7 mm vertical line, along with 66 μm Group A glass beads for comparison. Pressure gradients along the riser were measured and the Zenz type state diagrams were constructed for both type of particle. For Group C particles, the results show that the Zenz diagram has the usual characteristic form, but the minimum pressure gradient is much lower and is positioned at a significantly higher gas velocity. Multiple layers of Group C particles were found to adhere to the column wall, while only a fraction of the column inner surface was covered by the 66 μm particles. The effects of the electrostatics effect during solids conveying was also examined through the addition of anti-static particles and was shown to be less significant for the finer particles. This is because the tube inner surface is entirely covered by the particulates, which reduces the charging since only like materials are then in contact.

  • Solids volume fraction at the injection point in a Pneumatic Transport line
    Powder Technology, 1991
    Co-Authors: J.m. Beeckmans
    Abstract:

    Abstract The standard mass-flux equation for a Pneumatic Transport line predicts an infinite solids volume fraction at the point of injection of particles, where they have zero velocity in the direction of the axis of the conduit. This anomaly is resolved, and an equation is derived for volume fraction of solids in the vicinity of the injection point for uniformly accelerated particles.

Xu Cong - One of the best experts on this subject based on the ideXlab platform.

  • One-dimensional Model of a Multiple-unit Pneumatic Transport Reactor for Producing Titanium Tetrachloride——II. Simulated Results on Reactor Behavior
    The Chinese Journal of Process Engineering, 2005
    Co-Authors: Xu Cong
    Abstract:

    The multiple-unit Pneumatic Transport reactor is an innovative reactor suitable for gas-solid reaction system to avoid adhesion and agglomeration or enhance mass transfer rate. The effects of initial oxygen concentration, initial chlorine concentration and initial ratio of petrocoke to ore on the characteristics and behaviors of the multiple-unit Pneumatic Transport reactor for producing titanium tetrachloride are simulated and analyzed. It is found that the conversion of high grade titania feedstock (HGTF) can be enhanced by increasing the initial concentrations of oxygen and chlorine. But CaCl2 and MgCl2 can not be efficiently diluted by petrocoke while the initial concentration of oxygen is greater enough, and the conversion of HGTF can not be further enhanced by increasing initial concentration of chlorine that is excessively high. Moreover, the limiting conversion of HGTF exists for initial ratio of petrocoke to ore, and the heat balance for MPTB can not be achieved between 973 K and 1373 K while the initial concentration of oxygen or the initial ratio of petrocoke to ore are lower than a certain value.

  • One-dimensional Modeling of Multiple-unit Pneumatic Transport Reactor for Producing Titanium Tetrachloride——I. Mathematical Model
    The Chinese Journal of Process Engineering, 2004
    Co-Authors: Xu Cong
    Abstract:

    The multiple-unit Pneumatic Transport reactor is an innovative reactor, which consists of multiple units of a Pneumatic Transport riser and a dense-phase turbulent bed. It can be used as a reactor for gas-solid reaction system to avoid adhesion and agglomeration and enhance mass transfer rate. In this paper, a one-dimensional model has been established to describe the behavior of multiple-unit Pneumatic Transport reactor for producing titanium tetrachloride, in which the bubble assemblage model is used to calculate the reactant gas mass transfer rate from the bubble phase to the emulsion phase, and the particle-size distribution along vertical axis is determined by a population balance. Some important parameters such as reaction temperature, composition of solid particles, composition of gas phase, elutriation rate of solid and efficiency of reaction etc. can be solved from the model.

Hiroki Koyama - One of the best experts on this subject based on the ideXlab platform.

  • Modeling the thermal cracking of ethane and propane in a non-isothermal vertical Pneumatic Transport reactor
    Industrial & Engineering Chemistry Research, 1992
    Co-Authors: Hiroki Koyama, Joshua S. Dranoff
    Abstract:

    A model has been formulated for noncatalytic thermal cracking of ethane and propane in a non-isothermal, adiabatic, vertical, Pneumatic Transport reactor. This model takes into consideration hydrodynamic properties of the gas-solid mixture, gas-particle heat transfer, and a kinetic scheme involving 81 radical reactions among 11 molecules and 11 radicals. Simulations of ethane cracking at a fixed conversion show that the particle diameter and solid to hydrocarbon ratio have the greatest effect on reactor performance; an optimum particle diameter of 50 μm was found

O. Molerus - One of the best experts on this subject based on the ideXlab platform.

  • Pneumatic Transport of coarse grained particles in horizontal pipes
    Powder Technology, 1999
    Co-Authors: O. Molerus, U. Heucke
    Abstract:

    Pneumatic Transport in horizontal pipes takes place under turbulent pipe flow conditions, which means that the influence of the fluid density on the state of flow is significant. The aerodynamic resistance of coarse grained particles also depends on the density of the carrier fluid. Experimental evidence for the role of fluid mechanics is thus obtained only through the vast variation of the static pressure. Therefore, the theoretical considerations presented in this paper start with our own experimental results, obtained at static pressures in the range of 1 to 20 bars. The breakdown of the steady-state conveying at low fluid velocities (plugging limit) is identified as a specific indirect interaction between the fluid and the particles. The theory, as well as our own experimental results, reveal the decisive role of the slip velocity between the two phases for both types of Pneumatic Transport, namely the strand flow type and the fully suspended type. It shows that the pressure gradient due to the fluid manifests the most peculiar feature of the problem in the form of the self-sustained particle Transport. A unified representation of both types of particle Transport allows the reliable prediction of the type of Transport observed in plant practice, and a prediction of the pressure drop that is to be envisaged.

  • Overview: Pneumatic Transport of solids
    Powder Technology, 1996
    Co-Authors: O. Molerus
    Abstract:

    In the introduction of the paper the most significant advantages, disadvantages and pitfalls are summarized which characterize Pneumatic conveying technology. Historical remarks indicate a surprisingly high standard of Pneumatic Transport design which has been achieved already during the 19th century. The discussion of the development of prediction procedures for pressure drop and state of flow is used in order to show the development in the technology itself. Horizontal, as well as vertical upwards conveying, is taken into consideration. Unsteady states of flow, for example, plug flow in the form of naturally occurring plugs, is shown to be feasible in the case of coarse-grained particles with rather smooth surfaces. The various principles of plug forming devices for the Transport of fine-grained, and, hence, compressible bulk material are mentioned. The use of synergetic effects is demonstrated for vibration-induced Pneumatic conveying.