Application: Most of the implemented legislation requires limiting benzene concentration in the gasoline pool. This has increased the demand for high-performance C5 and C6 naphtha isomerization technology because of its ability to reduce the benzene concentration in the gasoline pool while maintaining or increasing the pool octane. The UOP Penex process has served as the primary isomerization technology for upgrading C5 / C6 light straight-run naphtha.
Description: UOP’s innovative hydrogen-once-through (HOT) Penex process results in subtantial savings in capital equipment and utility costs by eliminating the need for a product separator or recycle-gas compressor. The Penex process is a fixed-bed process that uses high-activity chloride-promoted catalysts to isomerize C5 / C6 paraffins to higher-octanebranched components. The reaction conditions promote isomerization and minimize hydrocracking.
Typically, two reactors, in series flow, are used to achieve high onstream efficiency. The catalyst can be replaced in one reactor while operation continues in the other. The stabilizer separates light gas from the reactor effluent.
Products: For typical C5 / C6 feeds, equilibrium will limit the product to 83 to 86 RONC on a single hydrocarbon pass basis. To achieve higher octane, UOP offers several schemes in which lower octane components are separated from the reactor effluent and recycled back to the reactors. These recycle modes of operation can lead to product octane as high as 93 RONC, depending on feed quality.
Penex process: Octane 86
Penex process/DIH: Octane 90
Penex process/Molex process: Octane 91
DIP/Penex process/DIH: Octane 93
Feed: Penex process can process feeds with high levels of C6 cyclics and C7 components. In addition, feeds with substantial levels of benzene can be processed without the need for a separate saturation section.