Batch Reactors Homogeneous Mass-Action Kinetics

1 BATCH REACTORS (HOMOGENEOUS MASS-ACTION KINETICS) 

The basic equations governing elementary chemical kinetics were introduced and discussed in Chapter 9. However, the discussion there is primarily concerned with how the molar production of chemical species (i.e., wk) depends on elementary reactions, which in turn depend on the species composition and the thermodynamic state of the gases. The objective here is to impose further constraints on the system to describe certain physical situations. Specifically, we consider the imposition of various combinations of fixed temperature, volume, and pressure. 

The mass conservation of species for a batch reactor, which is characterized by a fixed amount of mass, is given simply as 

If the temperature is not specified, then it must be determined via the solution of an energy balance. The energy balance for a system is written generally as 

Consider a simple constant-volume reactor or bomb, with no external work done on the system. Assume, however, that heat can be transferred to the system at a rate given by Newton s law of cooling as 

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The primary objective of this chapter is to develop low-dimensional representations of chemically reacting flow situations. Specifically these include batch reactors (corresponding to homogeneous mass-action kinetics), plug-flow reactors (PFR), perfectly stirred reactors (PSR), and one-dimensional flames. The derivations also serve to illustrate the approach that is taken to derive appropriate systems of equations for other low-dimensional circumstances or flow situations. 

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