PTQ Q3 2025 Issue

• LK-HK fractionation section : Very hard and severe fouling was noted; valve openings were choked. Moving downward in this section, the fouling severity increased. Heavy solid deposits were observed in the HK draw chimney tray. • HK-LGO fractionation zone : All trays were found clean and intact, with no signs of corrosion or fouling. • LGO PA, LGO-HGO fractionation, and HGO PA sections : Trays showed good mechanical integrity, with no fouling material present. • The HGO wash bed was also found to be clean. As a result of these observations, a total of 25 trays from the HN to HK zones were replaced with new Superflux trays to improve fouling resistance. Post-replacement, significant improvements were observed in overall column parameters, including sectional and overall column differential pressure (DP), which remained stable at approximately 0.4 Kg/cm² at equivalent throughput levels. Table 4 shows the DP profile of the column’s top section after replacing the trays. After two years of operation, at the end of 2022, the col - umn was opened and inspected. All trays were found in good condition without fouling (see Figure 7 ). A slight pitting was observed in the top few trays. In the HN-LK section, minor deposits were observed on the tray deck, displaying a black - ish colour. Analysis of these deposits indicated a very small phosphorus content, less than 2% by weight. The low con - centration of phosphorus compared to the 2018 shutdown clearly indicates the effective flushing of salts from the tray deck, which is attributed to the fouling-resistant properties of the Superflux trays. Conclusion This article discussed the successful collaboration between NEL and Koch-Glitsch in troubleshooting and resolving fouling challenges in their crude distillation column. As the first column to process petroleum in any refinery, the crude column’s performance is critical, influencing overall refinery throughput and feed to downstream units. Identifying the root cause of fouling required a thorough review of column operations, data analysis, and interpretation. To maintain column operation and throughput at desired levels, the intermediate solutions developed by NEL were instrumental. In addressing long-term fouling concerns, the utilisation of fouling-resistant tray technology emerged as an effective solution. This intervention significantly improved

Figure 6 Superflux tray with fixed valves to reduce resi - dence time of solids on tray deck reliability and extended run lengths, showcasing the advan - tages of tailored solutions for specific operational challenges. The findings presented contribute to the broader under - standing of the troubleshooting process, the solutions to maintain column operation, and fouling mitigation strategies in crude distillation columns. They underscore the combined importance of innovative solutions and advanced tray tech - nologies in enhancing performance and reliability. We acknowledge the gamma scan conducted by the Board of Radiation & Isotope Technology (BRIT) to confirm the location of foul - ing in the crude column. SUPERFLUX is a mark of Koch-Glitsch. References 1 Scott Hebert and Neil Sandford, Koch-Glitsch LP, “Considering Moving to Fixed Valves,” Chemical Engineering Progress (CEP), May 2016. Abhijit Gogoi is Head Process at Nayara Energy Limited, Vadinar, India, with more than 24 years of experience in crude distillation, hydrotreating/ hydrocracking, hydrogen generation, naphtha reforming, isomerisation, visbreaking, and sweetening technologies. Neil Sandford is a Global Technology Leader at Koch-Glitsch in Wichita, Kansas, with expertise in process modelling for debottlenecking, trou - bleshooting, and energy-saving objectives in distillation, absorption, and liquid-liquid extraction process units. Sandeep Yadav is Process and Application Leader at Koch Engineered Solutions India Pvt. Ltd. in Mumbai. He has more than 20 years of experience in troubleshooting, debottlenecking, and designing frac - tionation processes, including dividing wall columns and mass transfer equipment.

Figure 7 Superflux tray after two-year column operation

PTQ Q3 2025