Method for simultaneously injecting a fuel gas and an oxygen-rich gas into a unit

A method for simultaneously injecting a fuel gas and an oxygen-rich gas into a unit, comprising:

• providing a burner (1) which comprises
• a primary nozzle (2) for injecting the oxygen-rich gas, the primary nozzle being designed as a supersonic nozzle having a convergent portion (6) and a divergent portion (7) which adjoin each other at a radius of a narrowest cross-section (8), and
• a coaxial nozzle (3) having an annular outlet opening (4) for injecting the fuel gas located at an end face (5) of the burner (1), the coaxial nozzle being designed as a subsonic nozzle and being arranged coaxial to the primary nozzle (2);
• injecting the fuel gas, in the form of hydrogen or in the form of a fuel-gas mixture of hydrogen and a hydrocarbon-containing gas, at a fixed inlet pressure and a fixed inlet volumetric flow rate with respect to a planned thermal power of the burner (1);
• and
• varying an inlet pressure and an inlet volumetric flow rate of the oxygen-rich gas, thereby switching operation of the burner between a design state and a non-adapted state,
• wherein the design state of the burner is defined by a design inlet pressure and design inlet volumetric flow rate that lead to a pressure at the outlet of the primary nozzle to correspond to an ambient pressure, whereby the oxygen-rich gas exits from the primary nozzle with a maximum impulse flow, and
• wherein the non-adapted state of the burner is
• an over-expanded state characterized by an inlet pressure being smaller than the design inlet pressure, or
• an under-expanded state characterized by an inlet pressure being greater than the design inlet pressure.