STUDY ON THE POSSIBLE EXISTENCE OF MULTIPLICITY FEATURES IN ETHENE HYDROGENATION OVER PLATINUM BOEHMITE CATALYSTS

Abstract

The possible existence of multiplicity features, including ignition and extinction phenomena, are examined in ethene hydrogenation over a very short fixed bed of platinum/boehmite catalysts. Ethene hydrogenation is compared with carbon monoxide oxidation for which it has been claimed in several studies that multiple steady states can occur within the kinetic region. In our experiments an important experimental parameters is the size of the catalyst charge in the reactor. In ethene hydrogenation the multiplicity feature cannot be observed below a certain size of catalyst charge. On the other hand, in carbon monoxide oxidation this multiplicity can be observed regardless of catalyst charge size. From our observations, it is concluded that the multiplicity in ethene hydrogenation cannot be attributed to a purely kinetic process, but it results from the interaction of the chemical reaction and the heat transfer process.