DeltaChartToday's stringent environmental regulations often require Electric Power Plants to operate at much lower O2 levels than in the past.  Good combustion across the furnace becomes critical under these conditions.  CO measurement is a proven way to inform the plant of combustion conditions.  As you can see from the figure to the left, the operating zone for optimum combustion is a narrow region.
CO is a byproduct of incomplete combustion which increases rapidly when combustion occurs in a fuel rich environment.  Traditionally, in-situ O2 probes have been used to measure duct O2 after the combustion Zone.  This method of measurement can be effective for determining overall low O2 set point, but has proven to be very ineffective for burner tuning, and for maintaining optimum boiler performance.
One of the largest error inducing issues for O2 probes is in–furnace leakage.  On balanced draft units, air is pulled in through, cracks and openings in ductwork.  This air enters after the primary combustion zone, and causes the O2 probes to read high.  Since there is 21% O2 in air, the error offset on the O2 probes due to leakage can be great.  However, since the air leaking in has zero PPM of CO, the effects of the leakage on the CO measurement are negligible.  Therefore, the CO measurement offers true measurement for determining burner and boiler performance. Accurate and continuous measurement of CO is a critical tool for maintaining maximum boiler performance.  DMCC-CO monitors are a proven way to improve combustion - reduce NOx, LOI and slagging as well as improve efficiency.