Experimental methods for the determination of coke formation and

Experimental Methods for the Determination of Coke Formation and Deactivation Kinetics of Heterogeneous Catalysts 

Frequently the kinetic description of catalyst deactivation and coke formation is complicated by instationary reaction conditions prevailing during the respective experiments. In this paper two experimental methods are presented.which enable the determination of such kinetics avoiding this problem 4 Use of a concentration controled continuously operated recycle reactor 4 Experimentation at the thermodynamic equilibrium of the main reaction to determine the coke formation kinetics at well defined operating conditions 

The deactivation kinetics presented in this paper was evaluated on the basis of results from concentration-controlled experiments.Jn this experiments the feed composition of a continuously operated recyde reactor was adjusted by a control algorithm. keeping the product composition constant during the time on stream,despite of catalyst deactivation. 

This way an immediate calculation of actual activity was possibie ithout previous knowledge of the stationary kinetics of the reaction system. 

As gaschromatography. with its discontinuous integration results (calculated by a PC-XT computer) was applied for the analysis of the reaction,a conventional control-algorithm could not be used instead a model-based algorithm had been implemented.Fig 3 shows a flow sheet of this algorithm.lt consists of the actual process and a simplified model of the reaction and reactor. The chemical reaction taking place in the reactor is perfectly described by the feed composition c0, having 

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