Hydrocarbon conversion processes evolution

However, the detailed description of the FT product distribution together with the reactant conversion is a very important task for the industrial practice, being an essential prerequisite for the industrialization of the process. In this work, a detailed kinetic model developed for the FTS over a cobalt-based catalyst is presented that represents an evolution of the model published previously by some of us.10 Such a model has been obtained on the basis of experimental data collected in a fixed bed microreactor under conditions relevant to industrial operations (temperature, 210-235°C pressure, 8-25 bar H2/CO feed molar ratio, 1.8-2.7 gas hourly space velocity, (GHSV) 2,000-7,000 cm3 (STP)/h/gcatalyst), and it is able to predict at the same time both the CO and H2 conversions and the hydrocarbon distribution up to a carbon number of 49. The model does not presently include the formation of alcohols and C02, whose selectivity is very low in the FTS on cobalt-based catalysts. 

Decationation of the process of conversion of the Bronsted to Lewis acid sites that takes place in the temperature range of 400-500° as a result of the evolution of water can be visualized as shown in Fig. 8. The Bronsted acid sites are shown by (A), the Bronsted base by (B), and the Lewis acid site by (C). The specific molecular locale of the Lewis acid site is the three-coordinated aluminum. It can act as an acceptor of H or of one electron. As an acceptor of the H ion it may play an important role in initiating the carbonium type of reactions of the hydrocarbons by facilitating carbonium ion formation. On the other hand, it is also an electron acceptor. Turkevich and Stamires have shown this when they studied the ESR of triphenylamine (an electron donor) on a variety of zeolites. They found that the amount of electron transfer increased... 

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