Low NOx Burner Design and Analysis for Conceptual Design of Oxygen-Based PC Boiler

The objective of the low NOx burner design and analysis task of the Conceptual Design of Oxygen-Based PC Boiler study is to optimize the burner design to ensure stable ignition, to provide safe operation, and to minimize pollutant formation. The burners were designed and analyzed using the Fluent computer program. Four burner designs were developed: (1) with no over-fire gas (OFG) and 65% flue gas recycle, (2) with 20% OFG and 65% flue gas recycle, (3) with no OFG and 56% flue gas recycle and (4) with 20% OFG and 56% flue gas recycle. A 3-D Fluent simulation was made of a single wall-fired burner and horizontal portion of the furnace from the wall to the center. Without primary gas swirl, coal burnout was relatively small, due to the low oxygen content of the primary gas stream. Consequently, the burners were modified to include primary gas swirl to bring the coal particles in contact with the secondary gas. An optimal primary gas swirl was chosen to achieve sufficient burnout