PTQ Q3 2026 Issue

Static temperature (C)

1.97e+03 1.78e+03 1.00e+01 2.06e+02 4.03e+02 5.99e+02 7.96e+02 9.92e+02 1.19e+03 1.38e+03 1.58e+03

2.00e+03 1.97e+03 1.65e+03 1.69e+03 1.72e+03 1.76e+03 1.79e+03 1.83e+03 1.86e+03 1.90e+03 1.93e+03

Figure 7 Temperature contour profile of wall burner (front view)

prompting an evaluation of burner performance under cur - rent operating conditions. As part of this investigation, CFD simulations were conducted to assess flame characteris- tics and verify consistency with the design case. The study focused on characterising flame behaviour and heat flux dis- tribution in the fired heater burners. Key burner performance parameters such as flame shape, length, width, and temper- ature contours were quantified, and potential risks, including flame impingement on adjacent burners, furnace walls, or radiant tubes, were assessed. Such conditions could other - wise lead to localised overheating, tube metal temperature excursions, coking, or premature tube failure. A three-dimensional model incorporating actual burner geometry, fuel-air injection configuration, and radiation heat transfer was developed to realistically capture the multi-physics. The furnace has two burner configurations, namely floor-mounted burners and wall-fired burners, which were evaluated independently to understand their respec - tive flame envelopes and interaction with the surrounding tube bank and furnace architecture. The simulations provided spatial distributions of velocity, temperature, and species concentration, enabling the pre - diction of flame trajectory under design. The CFD results (see Figures 6 and 7 ) indicated that for both burner types, the predicted flame length and width remained well within the allowable design envelope. Adequate clearance was maintained from adjacent burners and radiation tubes, and no flame impingement or excessive localised heat flux was observed under the evaluated conditions. These findings provided confidence that the burner arrangement and flame characteristics under operating con- ditions are well within the design limits and are unlikely to be responsible for the observed decline in furnace efficiency. Conclusion The presented case studies demonstrate how CFD served as a critical diagnostic and design validation tool across diverse refinery systems. In the trickle bed reactor analysis, CFD enabled quantitative benchmarking of distributor designs, correlating improved liquid distribution with a lower maldis - tribution index validated through experiments.

tank circulation were shown to facilitate rapid dispersion and effective bulk mixing, thereby providing a technically robust basis for implementation. The CFD study played a key role in establishing confidence in the proposed configuration, enabling the team to proceed directly to a commercial trial without the need for additional experimental validation. The scheme was subsequently demonstrated successfully at one of the Indian Oil Corporation Limited ( IOCL) refinery locations with the potential benefit of approximately INR2,500-3,000 per MT through product quality upgradation, with no addi - tional capital investment. Case study D: Burner profile study for refinery furnaces Industrial fired heaters and furnaces are energy-intensive units in which burner performance governs flame stabil- ity, heat flux distribution and pollutant formation (NOx, CO, unburnt hydrocarbons). Conventional burner design and troubleshooting rely largely on empirical correlations or costly plant trials, offering limited insight into the coupled effects of turbulence, chemical kinetics, and radiative heat transfer. CFD provides a physics-based approach to simulate flow, mixing, combustion, and heat transfer within realistic fur - nace geometries, enabling the prediction of temperature, species distribution, and heat flux profiles under varied oper- ating conditions. Such simulations support burner evaluation with regard to fuel optimisation and emission reduction, and assess the risks related to flame impingement or localised tube overheating without interrupting plant operation. A decline in efficiency was observed in a refinery furnace, Figure 6 Temperature contour profile of hearth/floor burner (front view)

PTQ Q3 2026