ABSTRACT
The terms hydrotreating, hydroprocessing, hydrocracking, and hydrodesulfurization are used rather loosely in the industry because, in the processes hydrodesulfurization and hydrocracking, cracking and desulfurization operations occur simultaneously and it is relative as to which predominates. In this text, hydrotreat-ing refers to a relatively mild operation whose primary purpose is to saturate olefins and/or reduce the sulfur and/or nitrogen content (and not to change the boiling range) of the feed. Hydrocracking refers to processes whose primary pur-pose is to reduce the boiling range and in which most of the feed is converted to products with boiling ranges lower than that of the feed. Hydrotreating and hydrocracking set the two ends of the spectrum and those processes with a sub-stantial amount of sulfur and/or nitrogen removal and a significant change in boiling range of the products versus the feed are called hydroprocessing in this text.
