Title : Reduction of CO2 emissions in integrated VGO & diesel hydrotreater with energy reduction strategies & innovations
Abstract:
The Diesel Hydrotreater Unit (DHT) plays a crucial role in producing high-quality diesel by removing impurities and improving feedstock properties. As sustainability and cost-effectiveness become priorities, refineries are actively exploring strategies to enhance energy efficiency and minimize carbon emissions.
The DHT at HPCL (Hindustan Petroleum Corporation Limited) is uniquely complexed as an Integrated VGO & Diesel Hydrotreater Unit, processing both Vacuum Gas Oil (VGO) and diesel in separate reactors. There are two parallel trains of operation, one is having Vacuum Gas Oil as feed and the other one having Raw Diesel as feed. This integration increases operational intensity and energy consumption, making efficiency improvements particularly impactful.
This paper presents a set of impactful operational optimization initiatives undertaken in the Integrated Diesel Hydrotreater (DHT) unit, aimed at improving energy efficiency, reducing operating costs, and minimizing environmental impact. Key measures included hot feed maximization to reduce cold feed dependency, and the successful shutdown of one furnace through strategic operational adjustments without compromising throughput. Additional steps such as gas-to-oil ratio optimization, significant flare reduction, and stripping steam optimization were implemented to further enhance system efficiency. Export naphtha reduction was achieved by optimizing fractionator overhead conditions, while operational changes in the Sour Water Stripper (SWS) and Fractionator led to a substantial reduction in steam consumption—by nearly 80 tons per day.
Importantly, these improvements were realized without incurring any additional capital expenditure, making them highly cost-effective and immediately impactful. The absence of investment requirements enhances the attractiveness of these measures, especially from an operational sustainability standpoint. While this abstract highlights some of the most significant actions taken, it is important to note that several other optimizations were also implemented across the unit, each contributing cumulatively to the enhanced performance, energy conservation, and environmental responsibility of the DHT.
By implementing these changes—without any capital investment in new equipment or pipelines—annual savings of over 6,000 SRFT and CO2 reduction of around 19000 kg/hr were achieved annually. Beyond cost reduction, these initiatives align with broader sustainability goals by minimizing environmental impact while maintaining high operational performance.
In conclusion, optimizing energy usage in an Integrated DHT unit through strategic operational changes not only strengthens cost leadership but also advances sustainability in refining. These initiatives highlight the importance of continuous improvement and innovation in driving more efficient and environmentally responsible refinery operations.
