Theoretical equation was established for calculating the conversion of carbon monoxide in the primary flue gas into carbon dioxide by contacting the primary flue gas with the secondarily introduced fresh air. The experimental results confirmed the usefulness of this equation.
Though the combustion mechanism of the briquet （22 holes） may be much complicated, the mechanism of combustion could be simplified by careful attention upon the gas phase reaction ; the considerable extent of carbon monoxide in the primary flue gas could be converted into carbon dioxide by the intimate contact with hot fresh secondary air which was heat exchanged during it's introduction through the pipe installed at the center or the side of the briquet furnace.
The gas treating experiment was made to decrease the carbon monoxide content in the flue gas by using ash-briquet. The ash-briquet was placed on the upper part of burning briquets. The gas analysis showed the following ; when temperature of ash-briquet was below about 600 ℃, adsorption of carbon monoxide and dioxide into the porous briquet was verified. As the temperature went up to about 600 ℃ desorption of the gases from the ash-briquet was observed.