Effect of metals on carburization during catalytic cracking

Abstract

1. The authors have studied the effects of a number of metals on carburization during catalytic cracking and on the distribution of coke deposits over the catalyst particle cross-section. 2. Nickel, copper, and cobalt cause maximum deposition of coke on the catalyst. With 0.5–0.7 wt.% of one of these metals in the catalyst, the yield of coke is 3–3.5 times greater than in the case of the fresh aluminosilicate catalyst. 3. With up to 0.8–0.1 wt.% of chromium, molybdenum, or vanadium and up to 0.01 wt.% of cobalt in the catalyst, coke formation during catalytic cracking decreases. 4. The coke is distributed irregularly over the cross section of the catalyst bead; this nonuniformity increases with the metal content of the catalyst. Metals which promote carburization lead to greater nonuniformity of coke deposition over the diameters of the catalyst granules.