Date of Award


Degree Type


Degree Name

Doctor of Philosophy


The Pseudoadiabatic Operation (PO) of a fixed-bed catalytic reactor is an operating regime in which the temperature profile is monotonically increasing with the axial coordinate. It can be achieved in co-currently cooled reactors where the heat transfer fluid is a non-boiling liquid. This mode of operation has intrinsic advantages with respect to the hot-spot temperature profile usually experienced by packed bed units for exothermic reactions, such as better control of the temperature distribution and much less parametric sensitivity.;The PO was demonstrated experimentally for the first time in a pilot-plant-scale unit converting methanol to hydrocarbons.;Theoretical developments of the PO concept are also summarized in the present report. It was shown that the transition between PO and hot-spot operation occurs through an intermediate regime, and this was also confirmed by the experiments.;Based on mathematical simulations of the reactor, analytical "a priori" criteria for the determination of the operating regime were obtained. Comparison of the PO reactor with countercurrently cooled units showed remarkable advantages of the novel concept.;The experimental reactor used in this study was 2 cm in diameter and 2 m long, and it utilized a ZSM-5-class zeolite catalyst. It was observed that Pseudoadiabatic temperature profiles were consistently obtained, and that the Pseudoadiabatic Operation was compatible with high methanol conversions (80 to 100%). Under these conditions, the quality of the hydrocarbon products was satisfactory, the liquid fraction having a RON of 95-97.;The reactor throughput was comparable with that of existing methanol conversion processes.;Finally, it was verified that the process was flexible enough to provide different product distributions under the operating conditions tested.



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