ABSTRACT
Light paraffin hydroisomerization processes convert linear paraffins into branched paraffins of the same carbon number. Hydroisomerization is performed in the presence of hydrogen, which regulates the hydrogenation-dehydrogenation equilibrium and limits reactions leading to coking. Butane hydroisomerization produces isobutane and is usually employed in conjunction with aliphatic alkylation. Light naphtha hydroisomerization is employed to increase the octane number of light naphtha, which is then called “isomerate,” to be used as blendstock for motor gasoline. Hydroisomerization is performed in fixed bed reactors. Butane hydroisomerization and light naphtha hydroisomerization are two separate processes, but the process designs are nearly the same. The reaction chemistry of hydroisomerization is the same as that described for hydrocracking. Butane and light naphtha hydroisomerization catalysts are bifunctional catalysts. When the light naphtha composition is known, the likely fuel properties for any of the different hydroisomerization technologies can be estimated from performance data and the fuel properties.
