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Fluidized beds flow models

Differential Equations for Fluidized Bed Gasifier Model. In a hydrodynamical sense, the processes in fluidized bed gasifiers involve the interaction of a system of particles with flowing gas. The motion of these particles and gas is, at least in principle, completely described by the Navier-Stokes equations for the gas and by the Newtonian equations of motion for the particles. Solution of these equations together with... [Pg.160]

A number of fluidized bed reactor model versions are based on the cross sectional averaged two-phase transport equations as presented in sect 3.4.7. Bue to the vigorous particle flow the fluidized beds are essentially isothermal, so no energy balance is generally required . In addition, the necessary species mass (mole) balance can be deduced from (3.498). The solids are considered... [Pg.902]

Implicit Fractional Step Method for Solving the Two-Fluid Granular Flow Model Equations Applied to Fluidized Bed Flow... [Pg.1070]

Andres, M. B., Chen, Z., Grace, J. R., Elnashaie, S. S. E. H., Jim Lim, C., Rakib, M., et al. (2009). Comparison of fluidized bed flow regimes for steam methane reforming in membrane reactors a simulation study. Chemical Engineering Science, 64, 3598—3613. Ayturk, M. E., Kazantzis, N. K., Ma, Y. H. (2009). Modeling and performance assessment of Pd- and Pd/Au-based catalytic membrane reactors for hydrogen production. Energy Environmental Science, 2, 430—438. [Pg.52]

Abba lA, Grace JR, Bi HT. Thompson ML. Spanning the flow regimes generic fluidized-bed reactor model. AIChE Journal 2003 49 1838-1848. [Pg.94]

Two basic approaches are often used for fluidized bed reactor modeling. One approach is based on computational fluid dynamics developed on the basis of the mass, momentum, and energy balance or the first principle coupled with reaction kinetics (see Chapter 9). Another approach is based on phenomenological models that capture the main features of the flow with simplifications by assumption. The flow patterns of plug flow, CSTR (continuous-stirred tank reactor). [Pg.319]

Fluidized Bed Reactor Models Considering Detailed Flow Patterns Catalytic Cracking of Vacuum Gas Oil... [Pg.718]

FLUIDIZED BED REACTOR MODELS CONSIDERING DETAILED FLOW PATTERNS... [Pg.744]

At this time, we are unsure as to whether a packed-bed reactor (shell-and-tube type, modeled as a plug flow reactor) or a fluidized-bed reactor (modeled as an isothermal plug flow reactor with 10% feed gas... [Pg.1125]

The performance of fluidized-bed reactors is not approximated by either the well-stirred or plug-flow idealized models. The solid phase tends to be well-mixed, but the bubbles lead to the gas phase having a poorer performance than well mixed. Overall, the performance of a fluidized-bed reactor often lies somewhere between the well-stirred and plug-flow models. [Pg.58]

Wen, C. Y. and L. H. Chen, "Flow Modeling Coneepts of Fluidized Beds," n Handbook of Fluids in Motion, N. P. Cheremisinoff (Editor), Butterworth Publishers, Ann Arbor, MI, 1983. [Pg.487]

The effectiveness of a fluidized bed as a ehemical reactor depends to a large extent on the amount of convective and diffusive transfer between bubble gas and emulsion phase, since reaction usually occurs only when gas and solids are in contact. Often gas in the bubble cloud complex passes through the reactor in plug flow with little back mixing, while the solids are assumed to be well mixed. Actual reactor models depend greatly on kinetics and fluidization characteristics and become too complex to treat here. [Pg.35]

Knowledge of these types of reaetors is important beeause some industrial reaetors approaeh the idealized types or may be simulated by a number of ideal reaetors. In this ehapter, we will review the above reaetors and their applieations in the ehemieal proeess industries. Additionally, multiphase reaetors sueh as the fixed and fluidized beds are reviewed. In Chapter 5, the numerieal method of analysis will be used to model the eoneentration-time profiles of various reaetions in a bateh reaetor, and provide sizing of the bateh, semi-bateh, eontinuous flow stirred tank, and plug flow reaetors for both isothermal and adiabatie eonditions. [Pg.220]

As mentioned in Section 11.3, fluidized-bed reactors are difficult to scale. One approach is to build a cold-flow model of the process. This is a unit in which the solids are fluidized to simulate the proposed plant, but at ambient temperature and with plain air as the fluidizing gas. The objective is to determine the gas and solid flow patterns. Experiments using both adsorbed and nonadsorbed tracers can be used in this determination. The nonadsorbed tracer determines the gas-phase residence time using the methods of Chapter 15. The adsorbed tracer also measures time spent on the solid surface, from which the contact time distribution can be estimated. See Section 15.4.2. [Pg.430]


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See also in sourсe #XX -- [ Pg.452 , Pg.453 , Pg.454 ]




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Fluidized Bed Reactor Models Considering Detailed Flow

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Models fluidized bed

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