Title : Achieving net zero through diesel isotherming® excellence: A case study in sustainability, energy efficiency, and plant optimization at HPCL Mumbai refinery
Abstract:
The Diesel Hydro Processing Unit at HPCL Mumbai Refinery was successfully revamped to incorporate DuPont™ IsoTherming® Clean Fuel Technology, converting it into India’s first Diesel IsoTherming® Unit (DIU). This strategic transformation was aimed at producing Ultra-Low Suflur Diesel (ULSD) (<10 wppm) from high suflur feeds like SRD and LCO, while also enabling operational efficiency, energy conservation, and reduced emissions. Following the revamp, the plant’s capacity was enhanced by 133% (from 4,950 TPD to 6,825 TPD), while ensuring compliance with Euro VI fuel norms.
A major turnaround (TA) in 2024 served as a Launchpad for a series of energy efficiency and optimization initiatives. Furnace decoking, exchanger cleaning, and enhancement of the catalyst system led to significant improvements in heat integration and reactor performance. Operational strategies such as optimized Isotherming® pump RPM, recycle flow control, and gas-to-oil ratio reduction helped to reduce energy demand and improve thermal efficiency without any capital expenditure.
Challenges like high backwash frequency of filters causing off-spec diesel, exchanger fouling, and reactor pressure drop issues were successfully addressed. HPCL R&D developed HP-Ducer, a proprietary chemical that reduced the reactor differential pressure (DP), thereby improving unit reliability, reducing pump vibration, and enabling higher throughput. Control logic improvements (2oo3 trip voting) and real-time monitoring enhanced plant safety and availability.
These initiatives resulted in an annual energy savings of over 5,722 SRFT and CO? emission reduction of 4,957 tons/year, with no new equipment or piping required. Additionally, stripping steam and power optimization further contributed to lowering the unit’s energy intensity.
The case study demonstrates how a revamp backed by operational excellence and in-house innovation can deliver measurable environmental and economic benefits. The success of the DIU is a model for global refineries aiming to achieve sustainability goals, improve energy efficiency, and align with net-zero targets without large-scale investments
