Refining Processes Handbook
Filled with handy process flow diagrams, this comprehensive reference covers the technologies and operations of petroleum refineries and provides material on operating a jointly owned and operated refinery.
TABLE OF CONTENTS Refining Processes Handbook
Chapter Four: Gasoline Manufacturing Processes
CATALYTIC REFORMING
Catalytic reforming of heavy naphtha is a key process in the production of gasoline. The major components of petroleum naphthas are paraffins, naphthenes, and aromatic hydrocarbons. The relative amount of these hydrocarbons depend on the origin of the crude oil. The aromatic content of the reforming feed is usually below 20% of the total hydrocarbons whereas the paraffins and naphthenes vary between 10 and 70% depending on the origin of the crude oil.
The aim of catalytic reforming is to transform, as much as possible, hydrocarbons with low octane to hydrocarbons with high octane. The chemical reactions that lead to these changes are guided by a catalyst under well-defined operating conditions.
From the octane view point, the best hydrocarbon fuels for an internal combustion engine are isoparaffinic and aromatic hydrocarbons. For example, the aromatic hydrocarbons from C 7 to C 10 have research octane numbers (RON) of 118 to 171, whereas the corresponding cyclohexanes have octane numbers of 43 to 104. A similar comparison can be made between isoparaffins and normal paraffins.
The chemical reactions of catalytic reforming are grouped according to the respective hydrocarbon type.
REFORMING REACTIONS
Dehydrogenation
The naphthenic hydrocarbons are dehydrogenated to form aromatics (see Figure 4 1). The reaction is extremely fast, and the yields obtained are almost those predicted by thermodynamics. Also, the reaction is endothermic, ? H 50 kCal/mole. Dehydrogenation reactions are very important, because they increase the octane number and the reactions produce hydrogen. The only...
Copyright 2003 under license agreement with Books24x7
