| 摘要 |
PURPOSE:To make it possible to suppress easily the NOx value within a set allowable value and maintain a prescribed high temperature by the constitution that an air flow rate adjustment device and oxygen flow rate adjustment device receive signals from a calculator and send signals to an air control damper and oxygen control valve respectively to adjust the openings of the damper and valve. CONSTITUTION:An air flow rate indication and adjustment device 26 indicate the air flow rate when it receives output signals from a calculator 11 and at the same time adjusts the openings of an air control damper 14. Likewise an oxygen flow rate indicator 27 indicates the oxygen flow rate and at the same time adjusts the opening of an oxygen control valve 5. That is, when the concentration of the NOx in the exhaust gas by a NOx meter is in excess of a set allowable value for an air ratio when the ratio is over lambda1( 0.7) at which NOx value is at minimum, the rate of oxygen enrichment is fixed and the air ratio is reduced. Conversely when the air ratio is below lambda1 and the concentration of NOx by the NOx meter 5 is over the above-mentioned set allowable value, the rare of oxygen enrichment is fixed and the ratio is raised. And, when the temperature in a furnace 6, that is the temperature on a thermometer 4, is in excess of a set allowable value, the air ratio is fixed and the rare of oxygen enrichment is reduced, and conversely when the temperature falls below the set allowable value, the air ratio is fixed and the rare of oxygen enrichment is raised. |
