Catalytic Steam Cracking of Heavy Oil Feedstocks: A Review

In view of the worsening quality of crude oil, the use of unconventional petroleum feedstocks (heavy oils, bitumens, residues, etc.) in processing is becoming increasingly important. The processing of heavy oil feedstocks (HOF) requires the development of new effective techniques that will lead to an increase in the yield of light fractions, suppression of coke formation, and saturation of liquid products with hydrogen. At the same time, the capital and operating costs of the process should be minimized because the cost of production and transportation for HOF is several times higher than for light and middle oils. The present review summarizes the results of studies of the catalytic steam cracking of HOF—a potential alternative to conventional HOF upgrading based on carbon rejection (thermal cracking, visbreaking, catalytic cracking) or hydrogen addition (hydrocracking). The main differences of this process from HOF upgrading with water (aqueous pyrolysis in sub- or supercritical water), the peculiarities of the catalytic steam cracking depending on the process conditions and the type of catalyst, and possible mechanisms of water participation in the process were discussed.