Operational Modes and Bioreactor Concepts

Reactor operation includes discontinuous and continuous operations, steady-state and transient-state modes, and a group of intermediate modes that can be referred to collectively as semicontinuous operation. The modes of operation are compared in Fig. 3.30. 

A discontinuous stirred tank reactor (DCSTR) with ideal mixing conditions has no concentration profile in space. The process is, however, time dependent and thus has a concentration/time profile (c/t). 

A semicontinuous reactor (SCSTR) operation has most of the characteristics of a DCSTR in space, and the eft profile is typically as shown in Fig. 3.30 (see also Figs. 3.32 and 3.33). 

A continuous stirred tank reactor (CSTR) with ideal mixing has a uniform concentration both in time and space. As an important consequence, the concentration at the output (c ) is the same as that prevailing in the reactor 

The ideal continuous plug flow reactor (CPFR) has no profile at any point of the tube in the steady state. The process, however, advances along the tube, and so shows a longitudinal concentration variation. The profile of a CPFR in space is identical to the profile of a DCSTR in time in case of a constant volume process this fact is of great importance for process design ( kinetic similarity ). 

---