Achieving Uniform Combustion: A Case Study on Optimized Airflow Distribution in Fired Heaters

Combustion efficiency in fired heaters depends significantly on uniform airflow distribution across burners. Uneven airflow can lead to inconsistent combustion, reduced efficiency, and increased emissions. Recognizing this challenge, T Solutions India (TSI) conducted a comprehensive CFD modelling & analysis to optimize the combustion air duct of a fired heater system. This case study outlines the analysis, design improvements, and results achieved.

Challenges Identified

The primary issue was airflow inconsistency in the hot air duct, leading to uneven firing across burners. The existing duct system extended from the Forced Draft (FD) fan through the Air Preheater (APH) to individual burners. Variations in airflow distribution created inefficiencies in combustion, requiring precise intervention.

CFD Analysis

To address this, TSI performed a detailed Computational Fluid Dynamics (CFD) simulation and analysis of the entire air duct system. The analysis highlighted areas of airflow deviation and pinpointed bottlenecks affecting uniformity. Key observations included uneven airflow in the finger ducts and significant deviations in the main ducts, resulting in suboptimal burner performance.

Proposed Design Modifications

Based on the CFD findings, TSI recommended two critical design changes:

1. Installation of Baffle Plates: Strategically placed baffle plates within the finger ducts ensured balanced airflow distribution across burners.
2. Addition of Perforated Plates: These were installed in the main ducts to smooth out airflow irregularities, achieving a more uniform mass flow rate.

Results Achieved

The design modifications delivered remarkable improvements:

• Airflow deviations were reduced to within ±2% of the mean flow, significantly enhancing combustion uniformity.
• Overall system efficiency increased due to consistent firing across all burners, reducing energy loss and emissions.

Conclusion

This case study demonstrates how precise CFD analysis and thoughtful design modifications can transform combustion efficiency in industrial systems. TSI’s expertise in airflow optimization has set a benchmark for enhancing operational performance while ensuring environmental compliance. By addressing airflow distribution challenges with data-driven insights and innovative solutions, TSI achieved a sustainable, high-performing fired heater system.