Time variable simulated moving bed process

DETAILED DESCRIPTION According to this invention, the flow rates through the various individual sorbent compartments of a simulated chromatographic moving bed system are controlled to modify the specific steady state waveform characteristics of the process.
These modifications differentiate the process of this invention from conventional SMB processes The steady state waveform is modified by any combination of: (1) Operating the recirculation flow rates in a non-constant manner as a function of time within a given compartment or column during a step, (2) Operating inlet flows in a non-constant manner as a function of time during a step, and/or (3) Operating outlet flows in a non-constant manner as a function of time during a step.
The resulting process may be regarded as a "Time Variable Simulated Moving Bed" process (TVSMB).
Controlling such a process requires special procedures.
Highly responsive computer interaction monitoring and flow control devices are preferred.
It is recognized, however, that the benefits of this invention could be realized to some extent through the use of manual control procedures.
The claimed process involves the recognition that during any given step in a SMB process, the optimum flow rates in the system are time variable The basic recirculation flow rate for any SMB process; e.
g.
, the separation of fructose from a fructose-glucose solution, may be expressed as a function of time, B(t), where t elapses from t=0 to t=T.
The mathematical expression of this function may be derived from theoretical and/or empirical considerations, and it may be optimized through experience.
In any event, B(t) may be either graphically or mathematically expressed and may be encoded in conventional fashion in a microprocessor or other mechanical, electrical, or electromechanical controller.
This controller can be interfaced with one or more variable speed pumps or comparable flow control devices to maintain the desired recirculation flow rate at each instant of elapsed time during a step