Abstract
Cis- and trans-decalin were reacted over cracking catalysts to study the formation of aromatics in a particular fraction of the liquid products obtained in the fluid catalytic cracking process (FCC). A batch, fluidized bed CREC riser simulator reactor was used at 673 and 723 K and contact times varied from 3 to 15 s. Cis-decalin was much more reactive. Despite differences induced and measured in their accessibility indices, the catalysts led to similar activity profiles, suggesting that diffusion restrictions do not prevail. Products were C1-C12 hydrocarbons while coke was very low. Isomerization, cracking, hydrogen transfer, ring opening, ring contraction and alkylation reactions occurred and products from the various reactions were observed at very short reaction times. Bicyclic C10 naphthenics and alkyl-substituted C7-C11 aromatics or naphtheno-aromatics were the most important products. A reaction mechanism with three initial routes (isomerization, ring opening and direct hydrogen transfer reactions) was proposed.
Highlights
The fluid catalytic cracking of hydrocarbons (FCC) is a key refining process that converts complex mixtures of lowvalue heavy hydrocarbons into high-value light products with high efficiency and integration with other process units inA neat worldwide trend to add more residual hydrocarbon cuts boiling over 803 K into vacuum gasVol 23, No 7, 2012 oils (VGO), which are the typical feedstocks in fluid catalytic cracking process (FCC), can be observed, and at present technologies exist that can process full resid feedstocks.[2]
It is in this scene that opportunities exist to generate new catalysts to produce less aromatics in FCC, probably diverting from conventional Y zeolite, making it necessary to know about the mechanisms of aromatics formation in the LCO range
The conversion of decalin at high temperatures of 673723 K over laboratory deactivated compound FCC catalysts, which only differed in their accessibility properties, is not subjected to diffusion restrictions, reactions proceeding mainly on the Y zeolite component
Summary
The fluid catalytic cracking of hydrocarbons (FCC) is a key refining process that converts complex mixtures of lowvalue heavy hydrocarbons into high-value light products with high efficiency and integration with other process units inA neat worldwide trend to add more residual hydrocarbon cuts boiling over 803 K into vacuum gasVol 23, No 7, 2012 oils (VGO), which are the typical feedstocks in FCC, can be observed, and at present technologies exist that can process full resid feedstocks.[2]. According to the observed product yields, most important reactions are those of isomerization, cracking, hydrogen transfer, ring contraction, ring opening and, to a lower extent, alkylation.
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