| 摘要 |
The invention relates to a flame tube boiler with a hydraulically coupled preheating system for the combustion air. With this system, it is possible to achieve exhaust gas temperatures of 100 DEG C - possibly even 90 DEG C - when using natural gas for firing and thus to save an additional 2 to 3 percent of fuel. If the boiler is fired exclusively using natural gas, the heat exchangers of the preheating system for the combustion air are expediently formed by ribbed tubes, which have a low draught loss on the flue-gas side or combustion-air side and take up less space. If the boiler is fired alternately with natural gas and heavy oil, the primary heat exchanger (that supplied with flue gas) is designed as a double-tube or bare-tube construction (tube coil construction) because of the greater risk of fouling and only the secondary heat exchanger (supplied with combustion air) consists of ribbed tubes. The preheating system for the combustion air can also be designed as a multi-part system, each subsystem of which operates on the heat pipe principle. <IMAGE> |
