| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the deterioration of catalyst for a denitration device, the corrosion of equipment and wasteful consumption of ammonium by connecting one end of an exhaust gas recirculation duct to an air supplying duct and connecting the other end of the same to an economizer bypass duct. SOLUTION: One end of an exhaust gas recirculation duct 26 is connected to an air supply duct 5 and the other end of the same is connected to an economizer bypass duct 14. According to this method, the flow speed of exhaust gas, flowing through the economizer bypass duct 14, is increased by the suction of the exhaust gas recirculation duct 26 and the main stream of exhaust gas is formed in the economizer bypass duct 14. Therefore, even when the total amount of exhaust gas, flowing through a rear heat transfer wall 3, is reduced upon the low load of a boiler, an exhaust gas temperature at the inlet port of a denitration device 18 can be increased by increasing the opening degree of a bypass damper 15 for the economizer bypass duct 14 and conducting the high-temperature exhaust gas from a gas mixer 17 into the exhaust gas duct 13. According to this method, the deterioration of catalyst and the corrosion of equipment are prevented and, further, the wasteful consumption of ammonium can be prevented.</p> |
