refining india 2025 Role of nuclear gauges in delayed coking and ebullated bed hydrocrackers
David Williams berthold
In the dynamic landscape of petroleum refining, where efficiency, safety, and max- imising capacity are paramount, precise process measurements play a pivotal role. As refineries worldwide, including those in India, gear up for 2025’s ambitious energy goals by processing heavier and more com- plex feedstocks, the demand for reliable instrumentation intensifies.¹ India’s refining capacity is projected to exceed 400 million tons by 2025, with a focus on resid upgrading to meet rising demand for cleaner fuels and reduce import dependencies. Key units like delayed cokers (DCUs) and ebullated bed hydrocrackers are central to this strategy, but they pre- sent challenges, such as foaming, fouling, vapour holdup, and catalyst deactivation. Traditional measurement techniques often falter in these environments due to high temperatures, pressures, and multi- phase conditions. Advanced nuclear (radi- ometric) gauges offer a solution, providing non-invasive, repeatable data on density, level, and phase boundaries.² This article explores the principles of nuclear gaug- ing, its applications in DCUs and ebullated bed hydrocrackers, quantifiable benefits for Indian refineries, regulatory compliance, and strategic implications for sustainable operations. Nuclear Gauges: Principles and Industrial Relevance Nuclear gauges operate based on gamma attenuation, where gamma rays from a sealed source (such as Cs-137 or Co-60) pass through process material, and the detected attenuation correlates to density or level via the Beer-Lambert law.² These systems are non-intrusive and immune to temperature, pressure, vapour, or fouling, making them ideal for heavy oil processing. A typical setup includes a source-detector pair or vertical array for profiling, with scin- tillation detectors ensuring high sensitivity and stability. In Indian refineries, where crude flexibility and resid upgrading are priorities, nuclear gauges are increasingly relevant.¹ They enable real-time monitoring in harsh envi- ronments, supporting units like DCUs at HPCL Visakh, IOCL Panipat, and Reliance Jamnagar, and hydrocrackers at BPCL Mumbai and IOCL Vadodara.
Benefits and case studies for Indian refineries
Nuclear gauges deliver quantifiable impacts in Indian contexts: Benefit category Quantified impact (typical)
Description
Coke drum operation
+5-10% increase in drum fill utilisation
Optimises fill levels, boosts
throughput 7,8
Cycle optimisation
1-2 fewer switchover-related delays per week
Minimises downtime, enhances efficiency 6 Prevents entrainment, extends life 16 Improves reaction stability, yields 12
Hydrocracker stability Vapour hold-up insight
15-25% reduction in catalyst losses per cycle
Enables tuning of quench flows and
H 2 /oil ratios
Carbon monitoring Enhanced reliability
Early detection of fouling zones or upsets
Reduces maintenance, predicts issues 15
Avoids bed collapse, foam-overs,
Boosts safety, operational uptime
emergency shutdowns
Optimised catalyst exchange
Improves scheduling based on
Lowers costs, increases conversion
real-time behaviour
Increased throughput
Reduces downtime, maximises cycle efficiency
Aligns with India’s capacity goals Supports cleaner fuels production
Improved conversion yield
Better phase control for effective contact
Operational safety
Non-invasive, eliminates intrusive maintenance Complies with standards
Table 1
Figure 1 Series of density detectors mounted along the hydrocracker reactor
References 1 International Energy Agency (IEA). (2021). World Energy Outlook: India Energy Outlook. 2 Knoll, G. F. (2010). Radiation Detection and Measurement, 4th Edition. Wiley. 3 Jechura, J. (1998). Tutorial: Delayed Coking Fundamentals . Coking.com. 4 Thermo Fisher Scientific. (n.d.). Neutron backscatter versus gamma transmission analysis for coke drum level. 5 International Atomic Energy Agency (IAEA). (2005). Technical data on nucleonic gauges . 6 Berthold Technologies. (2021). Optimizing the critical level measurements in delayed coker units. Digital Refining . 7 Williams, B. (2017). Up or Down? Understanding nuclear gauges on Delayed Cokers . Refining Community. 8 Foster Wheeler. (2018). Delayed Coking – Best Practices for Operations and Safety, World Refining Association. 9 Berthold Technologies. (2025). Nuclear level devices on coke drums . 10 Digital Refining. (2023). Nuclear gauges and alternative level technologies in critical refinery applications. 11 Stratiev, D. (2022). The synergy between ebullated bed vacuum residue hydrocracking and fluid catalytic cracking processes in modern refining - commercial experience. ResearchGate. 12 Chevron Lummus Global. (2020). LC-Fining Technology Overview and Operating Guidelines , Licensing Brochure. 13 European Patent Office. (1995). Ebullated bed process with recycle eductor. 14 AquaEnergy Expo. (2023). Refinery Process. 15 Vivas Baez, J. (2021). Descriptors for deciphering the deactivation phenomena of vacuum gasoil hydrocracking catalysts. HAL Theses. 16 UOP Honeywell. (2019). Resid Hydrocracking and Catalyst Management, Technical Bulletin TB-8753. 17 Robinson, P. R. (n.d.). Clean liquid fuels from direct coal liquefaction. CiteSeerX.
mates control, extending run lengths and minimising downtime. Desalting synergy mitigates salt-induced fouling, with nuclear gauges ensuring sta- bility despite residuals.³ Case studies, like Lukoil’s unit, show 93% conversion with optimised catalyst use and fewer shutdowns.¹¹ , ¹⁰ Refineries like Reliance Jamnagar and IOCL Vadodara report reduced catalyst losses and improved yields, aligning with expansions at Panipat and Paradip.¹⁰ Conclusion As India advances toward crude flexibility and resid conversion, nuclear gauges trans- form bottleneck units into high-efficiency assets. By optimising cycles, catalyst man- agement, and stability – complemented by desalting – they drive capacity gains, cost savings, and safety. Refineries investing in these innovations future-proof operations, supporting sustainable growth and global competitiveness in 2025 and beyond. DID you know? Nuclear-level gauges, using gamma transmission, provide precise, non- contact detection, compensating for density variations and temperature fluctuations
scatter or radar struggle with foam, build- up, and calibration drifts.⁴ Nuclear-level gauges, using gamma transmission, provide precise, non-contact detection, compen- sating for density variations and tempera- ture fluctuations.⁵ These systems allow operators to track coke bed height, monitor foam growth, and optimise fill levels to 90-95% capac- ity, extending cycles and reducing switcho- ver frequency.⁶ Studies show 5-10% throughput increases without additional investments.⁷ , ⁸ Stability reduces anti-foam chemical use, cutting costs and environmental impact.⁹ In desalting contexts, where salt removal pre- vents corrosion and fouling, nuclear gauges handle contaminated feeds robustly.³ Real- world applications report 7% throughput gains and enhanced cycle efficiency.¹⁰ Application in Ebullated Bed Hydrocrackers: Monitoring Density Profiles Ebullated bed hydrocrackers (such as LC-Fining, H-Oil) upgrade vacuum resid by fluidising catalyst with hydrogen and oil, achieving up to 90% conversion of high- metal, high-sulphur feeds.¹¹ , ¹² Maintaining bed dynamics is complex, requiring con- trol of expansion (20-50% above settled height) to avoid settling or entrainment.¹³ Vertical nuclear density gauge arrays profile the reactor : high-density ebullated zone, intermediate liquid, fluctuating foam, and low-density vapour.¹⁴ This detects vapour hold-up, asphaltene build-up, and fouling, enabling adjustments to quench flows and H₂/oil ratios.¹² Reliable measurements support cat- alyst management : periodic addition/ withdrawal as metals and coke deactivate particles.¹⁵ , ¹⁶ Density data signals compac- tion, reducing consumption by 10-20% via targeted changes.¹⁷ Level gauging auto-
Application in Delayed Coking Units: Managing Drum Level and Foam
Delayed coking converts heavy residuals into lighter products through thermal crack- ing at 450-500°C. Feedstock is fed into coke drums, where vapours rise and coke accumulates, operating in batch cycles with alternating filling and decoking.³ Accurate level monitoring is crucial to track liquid, foam, and solid layers, preventing underfill- ing (lost capacity) or overfilling (foam carry- over, fouling, shutdowns). Traditional methods like neutron back-
Contact: david.williams@berthold-us.com
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