Patent ID: 9541280
Date: 2017-01-10
CPC Classifications: F22B,F23C,F23N

Claim:
1. An apparatus comprising: a steam generator structure defining a gas flow path reaching through heat exchange chambers including a steam-generating chamber and a preheating chamber downstream of the steam-generating chamber; a burner arranged to inject primary reactants, including fuel and combustion air, into the steam-generating chamber; a once-through water line having a) a preheating portion reaching through the preheating chamber, b) a first branch that receives preheated water from the preheating portion and reaches within the steam-generating chamber in a first serpentine configuration of turns and sections that reach oppositely back and forth end-to-end between the turns, and c) a second branch that receives preheated water from the preheating portion in parallel with the first branch and reaches within the steam-generating chamber in a second serpentine configuration of turns and sections that reach oppositely back and forth end-to-end between the turns, with the second serpentine configuration located downstream relative to the gas flow path of the first serpentine configuration; and a fuel injector arranged to inject staged fuel into the steam-generating chamber at a staged location downstream of the first serpentine configuration.