Method and apparatus for improved process control in combustion applications

A method for process control in a steelmaking combustion application, the method comprising:

• a) scanning off-gas produced by a steelmaking combustion application with a laser, the step of scanning comprising:
• i) targeting the off-gas with laser light corresponding to at least one CO absorption, and at least one H2O absorption, the laser light having a modulation frequency greater than the absorption line width of the targeted CO and H2O produced by the steelmaking combustion application;
• and
• ii) refraining from shining laser light on the off-gas during an off-interval,
• b) detecting transmitted laser light of step i),
• c) analyzing the detected laser light for select CO and H2O absorption lines;
• d) measuring background radiation during the off-interval;
• e) determining the CO concentration from the CO and H2O absorption lines and from the measured background radiation;
• and
• f) adjusting select inputs of the combustion application in response to the CO concentration.