Reheat type exhaust gas boiler

Abstract

A known reheat type exhaust gas boiler of the type having superheaters and reheaters disposed in parallel in the most upstream portion of an exhaust gas boiler main body, is improved by simplifying the structure and providing more effective recovery of heat from the exhaust gas. The superheaters and reheaters are divided into a plurality of stages. A high-temperature side superheater and a high-temperature side reheater are disposed in parallel in the most upstream portion of the gas flow. A low-temperature side reheater is disposed on the downstream side of the high-temperature side superheater, while a low-temperature side superheater is disposed on the downstream side of the high-temperature side reheater. The high-temperature side superheater and the high-temperature side reheater are formed so as to have an identical heat transfer tube outer diameter, an identical tube pitch in the transverse direction of the main body, an identical tube pitch in the longitudinal direction and an identical number of tube rows in the longitudinal direction. Likewise, the low-temperature side reheater and the low-temperature side superheater are formed so as to have an identical heater transfer tube outer diameter, an identical tube pitch in the transverse direction of the main body, an identical tube pitch in the longitudinal direction and an identical number of tube rows in the longitudinal direction.