Catalytic naphtha reforming

Abstract

Catalytic naphtha reforming (CNR) process was pioneered by UOP in the late 1940s to meet the burgeoning demand for high-octane motor fuels and has been a pivotal unit in petroleum refineries all over the world since its inception. The CNR process is specifically designed to convert naphtha to high-octane gasoline blending components called reformate. The low-octane components that usually have octane number in the range of 40–65 in naphtha, such as normal paraffins (n-paraffins), are converted into isoparaffins (i-paraffins) and naphthenes, and naphthenes are converted to aromatics in catalytic reformers to enhance the octane number of gasoline blends up to 90–105. In order to elaborate the dependency of octane number on chemical structure, numerous hydrocarbons are compared in Table 6.1 with respect to their research octane numbers. In general, aromatics possess the highest octane number, followed by naphthenes, olefins, and n-paraffins having the lowest octane number among other hydrocarbons listed. One of the essential characteristics of the CNR process is that it is the primary source of aromatics, such as benzene, toluene, and xylene (BTX) with more than 50 vol.% of production volume on worldwide basis. Moreover, it produces hydrogen as a by-product (also called net gas as a mixture of hydrogen, methane, ethane, and trace propanes), which can be utilized in hydrogen-consuming processes (i.e., hydrocracking, hydrotreating, hydrogenation, etc.) refinery-wide.