CHEN 3102 Lecture Notes - Lecture 48: Mecha, Volumetric Flow Rate, Exothermic Process
7 Apr 2015
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Rxns for targeted applications occur in a reactor. Semibatch: accumulation = (flow in or out, but not both) + generation. Key assumption: entering fluid is instantly mixed with all reactant volume. Simplify: steady state, single rxn, constant density. Key assumption: zero axial mixing like a bunch of mini cstrs that don"t mix with each other. Variable volume can use same eqns, just take into account the expansion/contraction. Expansion/contrction upon rxn accounts for change in volume w/ parameter. Can apply design eqns with modified volumetric flow rate. If no recycle stream --> imperfect mixing -- >pfr if infinite recycle ratio (r --> infinity) --> perfect mixing --> cstr. Mass moves in 2 ways: convection, uc. If you can"t predefine a system (don"t have blueprint, can"t look @ actual equipment) Residence time distribution function, f(t) this is by definition. It has to be normalized to equal 1. Cstr: we can only lump the density and heat capacity together under some assumptions.
