The patented ZEECO® FREE JET® burner is engineered for superior steam generation for Once Through Steam Generators (OTSG) applications. Designed with advanced computer simulations and real-world testing, the FREE JET is an ultra-low NOx burner capable of operating at low excess air with single burner capacities of 40 to 400 MMBtu/hr. It can also fire various fuel compositions, including hydrogen, without the need for external flue gas recirculation.