Gas Oil Conversion to Fuels and Petrochemicals

Over the years, the petrochemical manufacturer has continuously studied and contemplated the use of gas oil as a major feedstock to steam cracking for ethylene production. The interest in gas oil arose because of the declining availability of natural gas liquids in the United States, the desire to sidestep the competition with gasoline for naphtha supplies, and the increasing technical competence in processing gas oil in steam crackers.

Since the use of gas oil to manufacture ethylene would result in substantial coproduct yields of gasoline and fuel oil, it was recognized that the ability to optimize profits would depend on the degree to which petrochemical production was integrated with petroleum refining for fuels. An integrated facility would have the maximum flexibility to manipulate feedstocks and products as economic conditions oscillated.

In an integrated petrochemical and fuels manufacturing facility, vacuum gas oil could be utilized in a number of processing options which include:

• Direct blending into residual fuel oil.
• Hydrodesulfurization and then blending into residual fuel oil to lower its sulfur content.
• Catalytic cracking aimed mainly at supplementing or replacing gasoline production from naphtha.
• Hydrocracking to yield additional naphtha which would be used for gasoline production, thereby freeing straight run naphtha for petrochemical use.
• Hydrodesulfurization before use as steam cracker feedstock to manufacture ethylene, propylene, and other coproducts

To obtain meaningful perspectives on the use of gas oil, SRI International analyzed many major processing options of a chemical refinery, and they are presented in this report.