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Esfahan Refinery | Credit: Quds Online (June 15, 2021)

Esfahan Oil Refinery, also known as Isfahan Oil Refinery is Iran's second-largest and most product-diverse refinery, with current capacity of 375,000-420,000 bpd. Commissioned in 1979 involving American Fluor and German Thyssen/Krupp design, it underwent major expansion and quality upgrade programs worth €2.7 billion. The refinery produces Euro 4/5 standard fuels, supplies 20%+ of national petroleum products, and operates advanced water recycling systems. Ongoing RHU and RFCC projects will significantly increase gasoline production by 2026-2027. 

Feedstock & Capacity

Primary Feedstock is Iranian light crude oil from Maroon-Shadegan oil field in Khuzestan Province​ transported via 430-kilometer pipeline from Maroon field.

Most commonly cited curde oil processing capacity is 375,000 bpd consisting in three atmospheric distillation units with an individual nameplate capacity of 125,000 bpd each. A recent source (page dated June 11, 2024) mentions that the current refining capacity of Isfahan Petrorefinery is 420,000 bpd, which includes the production capacity of 13 million liters per day of Euro 5 and super gasoline and 26 million liters per day of Euro 4 diesel.

Current Operating Units

• Atmospheric Distillation Units (ADU/CDU): 3 units × 125,000 bpd = 375,000 bpd total
• Vacuum Distillation Unit (VDU)
• Visbreaker: Converts heavy residues
• Naphtha Hydrotreater (NHT)
• LPG Recovery Unit
• Catalytic Reforming Unit (CRU)
• Continuous Catalytic Regenerator (CCR)
• Isomax (Hydrocracker)
• Hydrogen Production Units (H₂ Production)
• Isomerization Unit
• Sulfur Recovery Units (SRU)
• Utilities and Supporting Systems

Plant Capabilities Upgrading Activities

By Jan 2017, capacity additions aimed at boosting the quantity and quality of fuel output included a 62,000-b/d naphtha treater, a 32,000-b/d continuous catalytic reformer (CCR), and 27,000-b/d isomerization unit.

Recent additions (2024-2025) include a kerosene Treatment Unit commissioned September 2025 for upgrading kerosene to Euro 5 standard (19,000 bpd capacity), and a Diesel Hydrotreater (DHT) adding 16 million liters/day of Euro 5 diesel production.

Ongoing/Planned Projects (2024-2027)​

1. RHU (Residue Hydrotreatment Unit): Desulfurization of atmospheric distillation tower bottoms
   • Will add ~12.5 million liters/day gasoline and ~1 million liters/day diesel​
   • Expected to help balance Iran's fuel consumption by 2026-2027​
2. RFCC (Residue Fluidized Catalytic Cracking Unit): Fluid bed catalytic cracking
   • Designed to reduce fuel oil production and increase light products​
   • Will add 600,000 t/y of propylene output in 2026.

Environmental and Water Management

Advanced Water Treatment:​

• Wastewater Treatment Capacity: 13,500 m³/day reuse water treatment​
• Oily Wastewater Treatment: 5,600 m³/day​
• Sanitary Sewage: 190 m³/day​
• CCRO (High Concentration Reverse Osmosis): Achieves 85% water recovery​
• Ultrafiltration (UF) and Reverse Osmosis (RO): First refinery in Iran to use UF technology at scale (900 m³/hr capacity)​
• Sources water from Shahin Shahr municipal wastewater, treats and reuses for cooling towers and utilities

Strategic Importance

• National Supply: Provides 20-24% of Iran's total petroleum products​
• Product Diversity: Widest range of petroleum products among Iranian refineries​
• Integrated Operations: Supplies platformate feedstock to adjacent Isfahan Petrochemical complex

References

1. MAPNA Group. Package C Project For The Development Of Isfahan Refinery
2. Monenco Group. 2007-2011 Isfahan Refinery Upgrading Project (Package C) 
3. Madyar Global Energy And Water Treatment Co. Isfahan Oil Refinery, Oily Water & Sanitary System (Commenced in 2018, Status: finished)
4. Oil&Gas Journal. Iran lets contract for Esfahan refinery project (Jan 17, 2017)
5. Asalem Municipality. Package C project of Isfahan refinery development (Start date: Feb 18, 2020, End date: Mar 20, 2021)  
6. Financial Tribune. Isfahan Oil Refinery to Become Petro-Refinery Holding Company (Mar 16, 2023)
7. Absun Energy. Esfahan Oil Refining Co., Sanitary Wastewater Treatment Plant (Sep 11, 2023)​
8. Absun Energy. Esfahan Oil Refining Co. (Nov 28, 2023)
9. Rahbord Energy. Developmental Projects on a Global Scale for Value Chains in Isfahan Petrorefinery (Jun 11, 2024)​
10. National Iranian Oil Refining and Distribution Company. Refineries (Apr 14, 2025).  ​
11. EnergyPress Iran. Saving water with advanced technology; Isfahan refinery's green step in the midst of crisis (Aug 11, 2025) ​
12. Tehran Times. NIORDC to boost refining capacity by 180,000 bpd, launch 3 fuel quality improvement projects (Sep 1, 2025).​
13. SHANA Petro Energy Information Network. Isfahan Refinery upgrades kerosene to Euro-5 standard (Sep 6, 2025) 
14. Energypress Iran. Get to know one of the largest refineries in Iran: Isfahan Oil Refinery (Sep 7, 2025) ​​