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Q&A

These digital transcripts are meant to share information on process safety practices in order to help improve process safety performance and awareness throughout industry. The goal is to capture and share knowledge that could be used by other companies or sites when developing new process safety practices or improving existing ones. The documents being shared have been used by an industry member, but this does not mean it should be used or that it will produce similar results at any other site. Rather, it is an option to consider when implementing or adjusting programs and practices at a site.

BY THEMSELVES, THESE DIGITAL TRANSCRIPTS ARE NOT STANDARDS OR RECOMMENDED PRACTICES. THEY ARE NOT INTENDED TO REPLACE SOUND ENGINEERING JUDGMENT. THEY DO NOT PRECLUDE THE USE OF ALTERNATIVE METHODS THAT COMPLY WITH LEGAL REQUIREMENTS. A SUBJECT MATTER EXPERT SHOULD BE CONSULTED PRIOR TO DETERMINING WHETHER A PRACTICE CAN BE USED IN ANY SPECIFIC SITUATION.

(2016) Question 25: For refinery complexes considering grassroots or brownfield expansion of gas oil conversion capacity, what are your typical capital expenditure (capex) costs and relative refinery margin improvement between FCC (fluid catalytic cracking) and hydrocracking? What are the key technology features that impact your economic decision? What are the crucial considerations that, if they include both technologies, to allow for future integration, especially around the changing gasoline/diese

In general, Marathon’s economic viewpoint is that hydrocrackers have better projected margins going forward than FCCUs, as they maximize higher valued ULSD over gasoline and have higher volume expansion (see Figure 1). This is driven by many factors mentioned in the primary response and is particularly attractive when ULSD is strong relative to gasoline and when natural gas or hydrogen) is inexpensive. Each company has a different viewpoint on this topic, so the opinion will vary somewhat across the industry.

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(2016) Question 26: We are interested in minimizing our black oil production from the FCC by recycling heavy cycle oil and/or slurry to our FCC feed hydrotreater for aromatic saturation and further cracking. Do you have any experience with this operating mode or recommendations for reduced slurry make via optimization of an FCC pretreat unit?

Limiting the discussion to HCO, if phenanthrene or anthracene are hydrotreated, one ring readily saturates and a second ring is relatively easy to saturate. A three-ring aromatic with one terminal ring saturated readily opens the saturated ring in an FCC riser, which makes a diesel boiling range diaromatic. If two rings are saturated, gasoline can be produced from this ring opening. As long as the molecule is linear (not Poly condensed), the saturated ring can enter the zeolite cage.

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