Multi-mode equipment set and use thereof

An equipment set comprising a burner, a valve unit (100), an oxidant-gas source (110) and a reducing-gas source (120):

• the burner comprising a multitude of injectors for injecting fluid jets into a downstream combustion zone, including:
• at least one first injector (11),
• a second injector (21) surrounding the at least one first injector (11), and
• a third injector (31) surrounding the second injector (21),
• wherein:
• the second injector (21) is fluidly connected to a source of a fuel,
• the third injector (31) is fluidly connected to a source of a combustion oxidant, and
• the at least one first injector (11) is equipped with a laval nozzle for supersonic fluid injection into the combustion zone, the at least one first injector (11) being fluidly connected, via the valve unit (100), to the oxidant-gas source (110) and to the reducing-gas source (120), the valve unit (100) being adapted to switch between the following modes of fluid supply to the at least one first injector (11):
• a first mode during which neither oxidant gas nor reducing gas is supplied to the at least one first injector for supersonic injection into the combustion zone,
• a second mode during which oxidant gas is supplied from the oxidant-gas source (110) to at least one of the at least one first injectors (11) for supersonic injection of the oxidant gas into the combustion zone, and
• a third mode during which reducing gas from the reducing-gas source (120) is supplied to at least one of the at least one first injectors (11) for supersonic injection of the reducing gas into the combustion zone.