US 12753916 B2 / Oct 6, 2026

Refractory block for low NOx burners with internal flue gas recirculation

A refractory apparatus may include a refractory block comprising a heat shield. The refractory block can include a group of flue gas ports that acts as a gateway for flue gas produced due to combustion downstream of a burner. A suction created in the burner drives the flue gas into the burner through the flue gas ports. A group of staged risers can be housed within the refractory block. The staged risers are protected in staged fuel riser housings in the refractory block. A discharge cone is located in the refractory block for flame stabilization in the burner.