Chapter 6 - Catalytic Cracking

Abstract

The concept of catalytic cracking is the same as that of thermal cracking, but it differs by the use of a catalyst that is not, in theory, consumed in the process. It is one of several applications used in a refinery that employ a catalyst to improve process efficiency and product slate. Catalytic cracking has a number of advantages over thermal cracking. This process produces less residuum and more useful gas oil constituents than thermal cracking. Finally, the process has considerable flexibility, permitting the manufacture of both motor gasoline and aviation gasoline. It can also accommodate variation in the gas oil production to meet changes in the fuel oil market. Furthermore two advances in the technology of moving bed catalytic cracking have greatly changed way it is operated, in comparison to the early processes. The more important of these advances was the introduction of crystalline aluminosilicate cracking catalysts, but the development of techniques to reduce catalyst attrition and metal erosion in moving bed cracking units has also been useful. In general, bio-feedstocks, catalytic cracker catalysts, or blends thereof achieve acceptable product yields and selectivity. As bio-feedstock use in the catalytic cracking units continues toward commercialization, the market potential will begin to allow catalyst manufacturers to allocate resources for more tailored catalyst development, greatly improving the yield and quality of desired products.