Cover
Vol. 1 No. 1 (2025): ETES

Published: December 31, 2025

Pages: 82-89

Research Article

A Novel Approach to Improve Octane Number and Reduce Sulfur Emissions in Regular Gasoline by Selective Naphtha Blending at Al-Diwaniyah Refinery

Ahmed Qasim Hamaddy* 1 Muhanad Mohan 1 Nazar Qasim 2 Wameeth Raad 1 Akeel Ibrahim 1 Abdul Kareem Salah 1
1Ministry of oil, Midland Refineries Company, Al-Diwaniyah Refinery, Al-Diwaniyah, Iraq
2Ministry of oil, Oil Products Distribution Company, Kirkuk, Iraq
History
  • Received: November 11, 2025
  • Revised: December 26, 2025
  • Accepted: December 28, 2025
  • Available Online: December 31, 2025
DOI

https://doi.org/10.65505/ETES-25-0012

Abstract

ABSTRACT  This paper proposes a low CAPEX selective blending strategy to upgrade regular gasoline quality in Diwaniyah Refinery. It tests the hypothesis that segregating heavy naphtha from the gasoline pool and blending light naphtha only with imported high octane gasoline can increase octane number (RON) and reduce sulfur content while decreasing import requirements. Four volumetric cases were evaluated: the refinery’s current practice (72 vol% imported gasoline + 28 vol% mixed naphtha) and three alternatives replacing mixed naphtha with light naphtha at 72/28, 67/33, and 62/38 vol%. Blends were prepared at ambient conditions and characterized using ASTM D2699 (RON) and ASTM D5453 (sulfur content). Replacing mixed naphtha with light naphtha at the same import ratio increased RON from 82.5 to 84.5 and reduced sulfur content from 157 to 70 ppm. Further reductions in imported high octane gasoline to 67 and 62 vol% maintained sulfur content below 100 ppm (77 and 87 ppm), with RON values of 83.5 and 80.5, respectively. These results were confirmed by Aspen Hysys simulation and ANOVA, indicating that heavy naphtha exerts the strongest negative effect on quality of regular gasoline. The proposed segregation requires only modifications to pipeline routes, enabling improved fuel quality and compliance with sulfur standards while reducing the need for imported gasoline in smaller refineries.

Keywords

References

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