Presents detailed information and study cases on experiments on hydrotreating catalysts for the petroleum industry Catalytic hydrotreating HDT is a process used in the petroleum refining industry for upgrading hydrocarbon streamsremoving impurities eliminating metals converting asphaltene molecules and hydrocracking heavy fractions. The major applications of HDT in refinery operations include feed pretreatment for conversion processes posthydrotreating distillates and upgrading heavy crude oil