drop by 20-25%. This provides additional operating margin, enabling a 5-10% increase in throughput within existing hardware constraints. Simultaneously, streamlined vapour–liquid traffic reduces reflux requirements by 10-15% while maintaining product specifications. Lower overhead dew points (reduced by 10-15°C) minimise water condensation and associated HCl corrosion. Continuous self- washing through wash oil circulation prevents the accumulation of salts and solids, extending tray life and improving the reliability of ageing units. Reduced corrosion also lowers consumption of neutralising chemicals and amine-based treatment systems, improving overall operational stability. The scheme delivers substantial energy and environmental benefits, achieving ~7,400 MTOE/year energy savings and reducing CO₂ emissions by ~24,000 tonnes per year, primarily through lower steam generation and reduced utility demand. From an economic perspective, the configuration delivers annual savings of approximately INR 18 crores, driven primarily by steam savings (~14 TPH) and reduced power consumption (~355 kW). With an estimated capital investment of ~INR 45 crores, covering ejectors, pumps, separators, and associated modifications, the payback period is approximately three years, achievable within a 30-45 day turnaround window (see Tables 3 and 4 ). Conclusion For existing refinery units, full-scale rebuilds are often constrained by economics and downtime. The proposed retrofit introduces a partition-based decoupling of steam-assisted stripping and steam-free rectification, integrated with optimised wash oil circulation through chimney tray modifications and targeted nozzle additions, enabling implementation within typical turnaround windows while retaining existing column infrastructure. The Bombay High crude case, representative of a ~8 MMTPA refinery, demonstrates substantial performance gains, including ~40% reduction in steam consumption and ~16% reduction in power usage, translating to annual
savings of approximately INR 18 crores. While these benefits are significant for light crudes (API > 38), the advantages become even more pronounced for heavier crudes with more dominating quantities of bottoms, where steam-intensive stripping dominates energy consumption. The proposed configuration delivers enhanced thermal efficiency, greater steam savings, reduced vapour load, and improved hydraulic performance, enabling higher throughput gains, particularly under challenging feed conditions. The integration of dry rectification and enhanced wash oil circulation improves yield recovery, operational flexibility, and equipment reliability, while simultaneously mitigating coking and corrosion-related limitations. “ The integration of dry rectification and enhanced wash oil circulation improves yield recovery, operational flexibility, and equipment reliability, while simultaneously mitigating coking and corrosion-related limitations ” From a revamp standpoint, the configuration requires minimal structural modifications, allowing practical implementation in brownfield units with low capital intensity and high return on investment. Although demonstrated in the context of Indian refineries, the concept is broadly applicable to existing refinery assets worldwide, offering a scalable pathway toward energy efficiency, emissions reduction, and improved operational resilience under evolving refining challenges.
VIEW REFERENCES
Ramanayya Gorle g.ramanayya@eil.co.in Grandhi Srivardhan srivardhan.g@eil.co.in
Narendra Kumar Paladugu pnarendra.kumar@eil.co.in Anil Kumar akumar@eil.co.in
Refining India
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