The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Hui Wang - One of the best experts on this subject based on the ideXlab platform.

  • apparent kinetics of a gas liquid liquid System of bunsen reaction with iodine toluene solution for hydrogen production through h2s splitting cycle
    International Journal of Hydrogen Energy, 2015
    Co-Authors: Ji Li, Armin Moniri, Hui Wang
    Abstract:

    Abstract A chemical splitting cycle of H2S to produce H2 for sustainable oil sands bitumen upgrading was recently developed in our research group which includes three reactions (Wang, H. Hydrogen production from a chemical cycle of H2S splitting. International Journal of Hydrogen Energy 2007; 32:3907–14): H2S + H2SO4 → S + SO2 + 2H2O (H2S Oxidation) (1) 2H2O + I2+SO2 → H2SO4 + 2HI (Bunsen Reaction) (2) 2HI → H2 + I2 (HI decomposition) (3) With iodine provided by iodine-toluene solution, the Bunsen reaction can be conducted at room temperature. Compared with the General Atomics stoichiometry and operation condition for the sulfur–iodine cycle, this modification can minimize or avoid problems such as side reactions, corrosion and iodine deposition. In addition, it reduces the unnecessary transportation of the excessive cycling agents in the cycle. This work studies the apparent reaction rate of the Bunsen reaction in a gas–liquid–liquid Multiphase System resulted from the presence of toluene in a closed, fixed-volume batch reactor using the initial rate analysis method. The reaction rate was found to be the first order with respect to SO2 and I2, respectively. The temperature effect on the reaction rate showed activation energy of 6.02 kJ/mol, which suggests that the rate-controlling step of the Bunsen reaction in the gas–liquid–liquid System is the step of SO2 absorption into the liquid phases. The variation of operating conditions including toluene/water volume ratio, agitation speed, and temperature confirmed the mass transfer rate-limiting step.

  • apparent kinetics of a gas liquid liquid System of bunsen reaction with iodine toluene solution for hydrogen production through h2s splitting cycle
    International Journal of Hydrogen Energy, 2015
    Co-Authors: Ji Li, Armin Moniri, Hui Wang
    Abstract:

    Abstract A chemical splitting cycle of H2S to produce H2 for sustainable oil sands bitumen upgrading was recently developed in our research group which includes three reactions (Wang, H. Hydrogen production from a chemical cycle of H2S splitting. International Journal of Hydrogen Energy 2007; 32:3907–14): H2S + H2SO4 → S + SO2 + 2H2O (H2S Oxidation) (1) 2H2O + I2+SO2 → H2SO4 + 2HI (Bunsen Reaction) (2) 2HI → H2 + I2 (HI decomposition) (3) With iodine provided by iodine-toluene solution, the Bunsen reaction can be conducted at room temperature. Compared with the General Atomics stoichiometry and operation condition for the sulfur–iodine cycle, this modification can minimize or avoid problems such as side reactions, corrosion and iodine deposition. In addition, it reduces the unnecessary transportation of the excessive cycling agents in the cycle. This work studies the apparent reaction rate of the Bunsen reaction in a gas–liquid–liquid Multiphase System resulted from the presence of toluene in a closed, fixed-volume batch reactor using the initial rate analysis method. The reaction rate was found to be the first order with respect to SO2 and I2, respectively. The temperature effect on the reaction rate showed activation energy of 6.02 kJ/mol, which suggests that the rate-controlling step of the Bunsen reaction in the gas–liquid–liquid System is the step of SO2 absorption into the liquid phases. The variation of operating conditions including toluene/water volume ratio, agitation speed, and temperature confirmed the mass transfer rate-limiting step.

Zhao Wang - One of the best experts on this subject based on the ideXlab platform.

  • a unified gas kinetic scheme for continuum and rarefied flows vi dilute disperse gas particle Multiphase System
    Journal of Computational Physics, 2019
    Co-Authors: Chang Liu, Zhao Wang
    Abstract:

    Abstract In this paper, a unified gas-kinetic scheme (UGKS) for Multiphase dilute gas-particle System is proposed. The UGKS Multiphase (UGKS-M) is a finite volume method, which captures flow physics in the regimes from collisionless multispecies transport to the two-fluid hydrodynamic Navier-Stokes (NS) solution with the variation of Knudsen number, and from granular flow regime to dusty gas dynamics with the variation of Stokes number. The reason for preserving the multiscale nature in UGKS-M is mainly coming from the direct modeling of the flow physics in the scales of discrete cell size and time step, where the ratio of the time step to the particle collision time determines flow behavior in different regimes. For the particle phase, the time evolution solution of the kinetic model equation is used in the construction of numerical flux, which takes into account the particle transport, collision, and acceleration. The gas phase is assumed to be in the continuum flow regime and evolves numerically by the gas-kinetic scheme (GKS), which is a subset of the UGKS for the Navier-Stokes solutions. The interaction between the gas and particle phase is calculated based on a velocity space mapping method, which solves accurately the kinetic acceleration process. The stability of UGKS-M is determined by the CFL condition only. With the inclusion of the material temperature evolution equation of solid particles, once the total energy loss in inelastic collision transfers into particle material thermal energy, the UGKS-M conserves the total mass, momentum, and energy for the whole Multiphase System. In the numerical tests, the UGKS-M shows multiscale property in capturing the particle trajectory crossing (PTC), particle wall reflecting phenomena, and vortex-induced segregation of inertial particles under different Stokes numbers. The scheme is also applied to simulate shock induced fluidization problem, where the simulation results agree well with experimental measurements.

Ji Li - One of the best experts on this subject based on the ideXlab platform.

  • apparent kinetics of a gas liquid liquid System of bunsen reaction with iodine toluene solution for hydrogen production through h2s splitting cycle
    International Journal of Hydrogen Energy, 2015
    Co-Authors: Ji Li, Armin Moniri, Hui Wang
    Abstract:

    Abstract A chemical splitting cycle of H2S to produce H2 for sustainable oil sands bitumen upgrading was recently developed in our research group which includes three reactions (Wang, H. Hydrogen production from a chemical cycle of H2S splitting. International Journal of Hydrogen Energy 2007; 32:3907–14): H2S + H2SO4 → S + SO2 + 2H2O (H2S Oxidation) (1) 2H2O + I2+SO2 → H2SO4 + 2HI (Bunsen Reaction) (2) 2HI → H2 + I2 (HI decomposition) (3) With iodine provided by iodine-toluene solution, the Bunsen reaction can be conducted at room temperature. Compared with the General Atomics stoichiometry and operation condition for the sulfur–iodine cycle, this modification can minimize or avoid problems such as side reactions, corrosion and iodine deposition. In addition, it reduces the unnecessary transportation of the excessive cycling agents in the cycle. This work studies the apparent reaction rate of the Bunsen reaction in a gas–liquid–liquid Multiphase System resulted from the presence of toluene in a closed, fixed-volume batch reactor using the initial rate analysis method. The reaction rate was found to be the first order with respect to SO2 and I2, respectively. The temperature effect on the reaction rate showed activation energy of 6.02 kJ/mol, which suggests that the rate-controlling step of the Bunsen reaction in the gas–liquid–liquid System is the step of SO2 absorption into the liquid phases. The variation of operating conditions including toluene/water volume ratio, agitation speed, and temperature confirmed the mass transfer rate-limiting step.

  • apparent kinetics of a gas liquid liquid System of bunsen reaction with iodine toluene solution for hydrogen production through h2s splitting cycle
    International Journal of Hydrogen Energy, 2015
    Co-Authors: Ji Li, Armin Moniri, Hui Wang
    Abstract:

    Abstract A chemical splitting cycle of H2S to produce H2 for sustainable oil sands bitumen upgrading was recently developed in our research group which includes three reactions (Wang, H. Hydrogen production from a chemical cycle of H2S splitting. International Journal of Hydrogen Energy 2007; 32:3907–14): H2S + H2SO4 → S + SO2 + 2H2O (H2S Oxidation) (1) 2H2O + I2+SO2 → H2SO4 + 2HI (Bunsen Reaction) (2) 2HI → H2 + I2 (HI decomposition) (3) With iodine provided by iodine-toluene solution, the Bunsen reaction can be conducted at room temperature. Compared with the General Atomics stoichiometry and operation condition for the sulfur–iodine cycle, this modification can minimize or avoid problems such as side reactions, corrosion and iodine deposition. In addition, it reduces the unnecessary transportation of the excessive cycling agents in the cycle. This work studies the apparent reaction rate of the Bunsen reaction in a gas–liquid–liquid Multiphase System resulted from the presence of toluene in a closed, fixed-volume batch reactor using the initial rate analysis method. The reaction rate was found to be the first order with respect to SO2 and I2, respectively. The temperature effect on the reaction rate showed activation energy of 6.02 kJ/mol, which suggests that the rate-controlling step of the Bunsen reaction in the gas–liquid–liquid System is the step of SO2 absorption into the liquid phases. The variation of operating conditions including toluene/water volume ratio, agitation speed, and temperature confirmed the mass transfer rate-limiting step.

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

  • a unified gas kinetic scheme for continuum and rarefied flows vi dilute disperse gas particle Multiphase System
    Journal of Computational Physics, 2019
    Co-Authors: Chang Liu, Zhao Wang
    Abstract:

    Abstract In this paper, a unified gas-kinetic scheme (UGKS) for Multiphase dilute gas-particle System is proposed. The UGKS Multiphase (UGKS-M) is a finite volume method, which captures flow physics in the regimes from collisionless multispecies transport to the two-fluid hydrodynamic Navier-Stokes (NS) solution with the variation of Knudsen number, and from granular flow regime to dusty gas dynamics with the variation of Stokes number. The reason for preserving the multiscale nature in UGKS-M is mainly coming from the direct modeling of the flow physics in the scales of discrete cell size and time step, where the ratio of the time step to the particle collision time determines flow behavior in different regimes. For the particle phase, the time evolution solution of the kinetic model equation is used in the construction of numerical flux, which takes into account the particle transport, collision, and acceleration. The gas phase is assumed to be in the continuum flow regime and evolves numerically by the gas-kinetic scheme (GKS), which is a subset of the UGKS for the Navier-Stokes solutions. The interaction between the gas and particle phase is calculated based on a velocity space mapping method, which solves accurately the kinetic acceleration process. The stability of UGKS-M is determined by the CFL condition only. With the inclusion of the material temperature evolution equation of solid particles, once the total energy loss in inelastic collision transfers into particle material thermal energy, the UGKS-M conserves the total mass, momentum, and energy for the whole Multiphase System. In the numerical tests, the UGKS-M shows multiscale property in capturing the particle trajectory crossing (PTC), particle wall reflecting phenomena, and vortex-induced segregation of inertial particles under different Stokes numbers. The scheme is also applied to simulate shock induced fluidization problem, where the simulation results agree well with experimental measurements.

Kai Sundmacher - One of the best experts on this subject based on the ideXlab platform.

  • cyclic operation of a semi batch reactor for the hydroformylation of long chain olefins and integration in a continuous production process
    Chemical Engineering Journal, 2019
    Co-Authors: Kai Sundmacher, Michael Jokiel, Karsten Ratze, Nikolas Maximilian Kaiser
    Abstract:

    Abstract The transition to renewable feedstocks in chemicals production requires innovative processes which are able to exploit the special properties of the feed material while still maintaining high process performance. Flexible semi-batch processes offer the advantage of dynamic adaptation to changing process requirements but suffer in terms of automation and production capacity where continuous processes excel. Combining the flexibility of a semi-batch reactor with the reliability of a continuous downstream process is the motivation for the application of a repeatedly operated semi-batch reactor (RSBR) concept to the hydroformylation of 1-dodecene in a n-decane/DMF thermomorphic Multiphase System (TMS). In order to predict the dynamic process behavior, a detailed dynamic process model is introduced and compared to a corresponding steady-state model. In addition, the RSBR concept is embedded in a miniplant process to prove its feasibility and convergence to a cyclic steady-state experimentally. Finally, the collected experimental data is compared to the results from the dynamic process model indicating accurate predictions of the integral process behavior.

  • helically coiled segmented flow tubular reactor for the hydroformylation of long chain olefins in a thermomorphic Multiphase System
    Chemical Engineering Journal, 2019
    Co-Authors: Michael Jokiel, Kai Sundmacher, Nicolas Maximilian Kaiser, Peter Kovats, Michael Mansour, Katharina Zahringer, K D P Nigam
    Abstract:

    Abstract To intensify new or existing chemical processes, novel reactor designs have to be developed. For a homogeneously catalyzed Multiphase model reaction, the hydroformylation of 1-dodecene, Kaiser et al. [13] theoretically derived a promising tandem reactor System applying a model-based rector synthesis and dimensioning approach. The reactor tandem, consisting of a helically coiled tubular reactor (HCTR) followed by a continuously stirred tank reactor (CSTR), was constructed and firstly operated within this work. For the validation of the reactor design methodology, a comprehensive hydrodynamic study focusing on the HCTR was performed. Different complementary techniques were used to investigate the geometry influences on mixing and the gas-liquid mass transfer, and liquid phase mixing in smaller model geometries. Since the same Reynolds-number and flow regime in the model geometries and the HCTR were ensured, the transfer of the results between these geometries was possible. The outcome confirms, that the geometrical parameter only minor influence the excellent mixing properties of coiled tubes and the helix geometry has enhanced gas-liquid mass transfer rates. In a next step, the HCTR + CSTR-tandem was operated with closed catalyst recycle and optimized reaction parameters. Thereby, full conversion of 1-dodecene and a selectivity of up to 0.70 to the linear aldehyde, tridecanal, were achieved. These values match the predictions of the numerical calculations and are higher than published results for this process. The outcomes of this study confirm the assumptions made by Kaiser et al. [13] during the reactor dimensioning and validate the reactor network design approach.

  • surrogate modeling for liquid liquid equilibria using a parameterization of the binodal curve
    Processes, 2019
    Co-Authors: Christian Kunde, Tobias Kesler, Steffen Linke, Kevin Mcbride, Kai Sundmacher, Achim Kienle
    Abstract:

    Computational effort and convergence problems can pose serious challenges when employing advanced thermodynamic models in process simulation and optimization. Data-based surrogate modeling helps to overcome these problems at the cost of additional modeling effort. The present work extends the range of methods for efficient data-based surrogate modeling of liquid–liquid equilibria. A new model formulation is presented that enables smaller surrogates with box-constrained input domains and reduced input dimensions. Sample data are generated efficiently by using numerical continuation. The new methods are demonstrated for the surrogate modeling and optimization of a process for the hydroformylation of 1-decene in a thermomorphic Multiphase System.