How much octane will be destroyed with Tier 3 —
How much octane will be destroyed when the heat is turned up on gasoline desulfurizers to make 10 ppm sulfur gasoline?
This critical question was studied thoroughly in paper studies during development of the Tier 3 standard. It was known this number would have big impact on the costs for Tier 3 compliance.
But the answer in the paper studies was based on vendor estimates which were known to be highly uncertain.
In its linear programming (LP) and cost studies, EPA estimated the incremental octane destruction for Tier 3 gasoline, versus Tier 2, to be 0.5 AKI (AKI = anti-knock index = (RON+MON)/2)) octane units.
In September 2013, EPA commissioned an independent peer review of its modeling and cost analysis. The peer review pointed to large uncertainties in the estimated technical performance and costs of naphtha desulfurization process. The following excerpt is taken from that peer review:
“FCC Naphtha Desulfurization Technology Review –Technical data for FCC naphtha desulfurization processes were provided to the EPA by four well-known refining process technology suppliers. This information contains widely varying levels of technical completeness. The EPA Model heavily relies on information from the technology vendors that provide the least amount of technical detail, especially Vendor number one. Conclusions that are reached by the vendors who provided only minimal technical back-up are difficult to support, especially when these conclusions appear to be divergent from typical industry experience. “
It also pointed to weaknesses in capital cost estimation and in accounting for differences in feed quality, especially those caused by differences in the extent of FCC feed hydrotreating in the US refineries.
During the Tier 3 phase in, 2015-2019, conventional wisdom said the incremental octane destruction for Tier 3, versus Tier 2, would be 0.5. This became a well-accepted belief. But it had no foundation. Nobody could point to any hard data supporting that conventional wisdom.
Starting in 2015, our client group did pilot plant studies and field tests, using modern analytical tools and models, to measure octane loss in deep desulfurization of FCC gasoline. Our results show typical octane loss in North American refineries will be 2.5, that’s 5 times higher than has been expected.
All the data, analysis, and models from our 3-year Tier 3 research project are in our multi-client annual reports which are available to anyone at a small fraction of the cost of the work. If you believe Tier 3 is important to your company, then your company should get our reports! Please contact George Hoekstra, firstname.lastname@example.org +1 630 330-8159, and request an offer letter and Table of Contents.