Fluidized Bed Reactor Models Considering Detailed Flow

7 FLUIDIZED BED REACTOR MODELS CONSIDERING DETAILED FLOW PATTERNS 

Each term in this equation has the dimension [kmol A/mjs]. As in Section 12.3, in statistically stationary flow, fluctuations of the variables around the averaged or mean values can be described by the transient term in this and the following equations. The second term represents the transport of the species by convection in the three dimensions Zj, the third that by molecular diffusion, and the fourth term is the interfacial transfer from the solid to the gas phase. The superscript 5 in the fourth term refers to surface conditions of the solid. 

Values for the interphase mass transfer coefficient kgA can be calculated from y rcorrelations (see Chapter 3). Specific correlations for fluidized beds can be found in Perry [1984]. 

The solution of the continuity equations for the species requires the knowledge of the local gas and solids volume fractions % and e pressures P and Ps, temperatures Tg and T and velocities Ug and Us. These can be calculated from the total continuity equations and the momentum and energy equations. In the absence of accumulation of species on the solid  

The solid phase shear stress tensor r is defined by  

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Fluidized Bed Reactor Models Considering Detailed Flow Patterns Catalytic Cracking of Vacuum Gas Oil... 

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