A recent survey, illustrates how North America refiners are meeting the Tier 3 regulations. The majority of refiners are meeting the regulations by increasing hydrotreating severity either with pre-treating FCC feed or post-treating FCC naphtha. This option increases the refinery H2 consumption and reduces the run length of these hydrotreaters. For some refiners, pre-treating FCC feed is still not sufficient and can sometimes present a heat balance challenge for the FCC unit. While post-treating is effective for reducing the sulfur content, it saturates aromatics and olefins resulting in octane loss in the FCC naphtha. This can be exacerbated at refineries that consume an increased diet of shale‐derived crudes, which are naturally light and produce low sulfur, but also low octane, gasoline This paper examines case studies to highlight a few different options around the FCC units for maximizing overall refinery octane: Case 1) Feed and operational changes to maximize LPG olefins to Alkylation Unit and improve octane; Case 2) Undercutting FCC naphtha to reduce post-treat requirement and improve octane; Case 3) Catalytic solution to maximize LPG olefins to Alkylation Unit and improve octane; Case 4) Additives to boost LPG olefins to Alkylation Unit and improve octane; Case 5) Gasoline Sulfur Reduction (GSR®) Technology to reduce post-treat requirement and preserve octane ; and Case 6) Combining multiple approaches. Source: Grace Catalagram, Fall 2017, p.8.
Image: Industry Survey on Meeting Tier 3 Regulations
TCGR Note: Interestingly, the demand for 93 octane has risen from 7.8% back to 11.3% market share since 2008 in the U.S. (EIA). To meet CAFÉ (mileage) standards, has been for automobile have to use smaller turbocharged gasoline engines. Each refiners solution will likely be site specific but the two (2) best options are using could be a butylene C4= specific FCC catalyst to boost alkylation production and additives such as Grace’s D-Prism to reduce sulfur.