Fibrous substrate-based hydroprocessing catalysts and associated methods

Catalysts are disclosed comprising fibrous substrates having silica-containing fibers with diameters generally from about 1 to about 50 microns, which act effectively as "micro cylinders." Such catalysts can dramatically improve physical surface area, for example per unit length of a reactor or reaction zone. At least a portion of the silica, originally present in the silica-containing fibers of a fibrous material used to form the fibrous substrate, is converted to a zeolite (e.g., having a SiO2/Al2O3 ratio of at least about 150) that remains deposited on these fibers. The fibrous substrates possess important properties, for example in terms of acidity, which are useful in hydroprocessing (e.g., hydrotreating or hydrocracking) applications.