New Microsoft Word Document (4) - FIELD OF THE INVENTION...

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FIELD OF THE INVENTION The invention relates to a catalytic reforming process for converting a heavy cracked naphtha to gasoline. In particular the invention relates to a process which makes use of a large pore catalyst which is both effective and demonstrates a reduced aging rate, particularly when processing heavy cracked naphtha. BACKGROUND OF THE INVENTION The subject of the invention is an improvement in a catalytic reforming process. Catalytic reforming is a refining process that uses selected operating conditions and selected catalyst to convert naphthenes and paraffins to aromatics and isoparaffins. Hydrocarbon molecules are predominantly rearranged without altering the number of carbon atoms in the molecule. Petroleum is subjected to fractional distillation in fractional distillation towers including a pipe still, a vacuum pipe still and associated distillation towers. The resulting fractions range from the lightest hydrocarbon vapors including methane, ethane, ethylene, propane, and propylene to a heavy vacuum residuum having an initial boiling point of 1100° F. Intermediate between propane/propylene and the heavy vacuum residuum fractions are a number of intermediate fractions. The cut points of each of those intermediate fractions is determined by refinery configuration and product demand. These intermediate fractions include naphtha, kerosene, diesel. gas oil and vacuum gas oil. Any of these fractions which is taken directly from the fractional distillation of crude petroleum is referred to as "straight run." A large body of technology has been developed for the conversion of one intermediate fraction to another. Converted fractions are by definition not straight run and are referred to as coker or cracked. Converted fractions differ from straight run fractions, particularly in the distribution of suibstituent components in the fraction. The substituent components include paraffins, naphthenes and aromatics. In the catalytic reforming process, a hydrocarbon fraction containing paraffins and naphthenes is contacted with a catalyst which promotes the dehydrogenation of naphthenes to aromatics; isomerization of paraffins and naphthenes; hydrocraeking of naphthenes and paraffins and other reactions to produce an octane enhanced liquid and hydrogen. Catalysts effective in carrying on these reactions are referred to as dual function catalysts because they exhibit the capability of both selectively cracking and hydrogenating. Dual function catalysts often demonstrate high initial activity. However, these catalysts are particularly susceptible to decline in
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activity in part due to deposition of coke on the catalyst. When the activity declines below a certain level, which depends on the product desired and the plant capabilities then the catalyst must be regenerated. This often results in substantial down time. Catalyst activity over time, referred to as stability, is therefore
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This note was uploaded on 02/17/2011 for the course CHEM ENGG 101 taught by Professor Mister during the Spring '11 term at University of Engineering & Technology.

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New Microsoft Word Document (4) - FIELD OF THE INVENTION...

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