Coordinated control method of air preheater bypass damper and economizer bypass damper

摘要

PROBLEM TO BE SOLVED: To early raise a denitrification inlet gas temperature while cooperating a control of an economizer bypass damper and an air preheater bypass damper and to prevent a low temperature end corrosion of the preheater. SOLUTION: After a boiler is started from a stop state, opening of the air preheater bypass damper 12 is conducted by an air preheater bypass damper opening command 41. After an air preheater mean temperature 24 exceeds a set value, air preheater bypass damper correcting opening commands 33, 35a are added to an air preheater bypass damper opening command 31 to obtain an air preheater bypass damper opening command 39, thereby regulating the opening of the damper 12. Simultaneously, an economizer bypass damper correcting opening commands 51, 53 are added to an economizer bypass damper opening command 49 to obtain an economizer bypass damper opening command 20, thereby regulating the opening of the economizer damper 10.