Analysis and demonstration of a control concept for a heat integrated simulated moving bed reactor

Successful operation of a simulated moving bed reactor requires a strategy to control switching of the inlet and outlet positions between different fixed-bed segments. This is due to the narrow operation window in which an ignited state can be maintained and complete conversion is assured in exothermal irreversible reactions. This work compares three control concepts, which are either based on monitoring the reaction front or the leading thermal front. Another feature investigated is the length of the observation time considering a single switching period and a complete cycle. For the concept favored some efforts regarding parameterization are made. The wider range of temperature set-points applicable can be related to stability limits of an associated hypothetical true moving bed reactor. Responses to step inputs in feed concentration and total flow rate are investigated experimentally in order to evaluate the performance of the controller suggested. An ignited state of the reactor could be maintained successfully for 3.5 days.

► We investigated three control concepts for the switching time of an adiabatic SMBR.
► Number of sensors and different temperature fronts were considered.
► Range of temperature set-points identified.
► Proper disturbance rejection of suggested concept.
► Experimental work confirmed robust reactor control.