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Unformatted text preview: CBE 320 December 8, 2009 Transport Phenomena Problem Session XV Part B: Mass Transport 1. Reaction in a packed bed reactor. A tubular packed bed reactor (radius R ) contains stationary catalyst particles that cause species A to react via A → products as illustrated in the figure below. v z = constant R = - k ’’a c A 1 A ( ) z v z = constant c z=0 = c A A0 ( ) Although the reaction is actually heterogeneous, the apparent homogeneous reaction rate (occurring over a volume containing many particles) is given by R A =- ( k ′′ 1 a ) c A , where a is the surface area per unit volume. The presence of the particles causes the velocity profile to be uniform (i.e., v z = constant). Assuming that the inlet concentration of A in inert liquid B is c A , that diffusion is negligible relative to convection (in which case the convective molar flux can be written N A,z = c A v z ), that the process occurs at constant temperature, and that mass transfer limitations to reaction are negligible, use a shell...
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This note was uploaded on 05/06/2010 for the course CBE 320 taught by Professor Staff during the Fall '08 term at University of Wisconsin.
- Fall '08