| 摘要 |
PURPOSE:To prevent NOX and the like from being abruptly increased in a title method wherein two sets of burners are alternately combusted and combustion air is preheated with waste gas heat by supplying fuel upon starting of combustion, performed when a burner is changed over, after starting of supply of combustion air, and after a predetermined time. CONSTITUTION:When a fuel is combusted by a burner 7a and waste gas is exhausted by the other burner 7b, a fuel changeover valve F1 associated with the burner 7a and a combustion air changeover valve A1 are opened while a waste gas changeover valve E1 is closed and the burner 7b is reversely changed over in its valve. Then, when the combustion burner is changed over, a fuel changeover valve F1 associated with the burner 7a is closed and thereafter the combustion air changeover valve A1 are closed and simultaneously a waste gas changeover valve E2 associated with the burner 7b is closed and the waste gas changeover valve E1 and the combustion air changeover valve A2 are opened. Then, after a predetermined delay time since the combustion air changeover valve A2 is opened, the combustion changeover valve F2 is opened and a fuel is supplied to a fuel injection nozzle 16b to start combustion. |
