富氧气氛下受热面改造的经济性分析

Economy analysis for heating surface retrofits under oxygen-rich atmosphere

富氧气氛下由于烟气量的减少以及锅炉热效率提高所带来的燃料量的减少使得烟气中的粉尘量得到一定的降低,为电站锅炉水平烟道烟气流速的提高带来了可能。增加烟气流速虽然强化了传热,但同时也增大了风机的电耗。采用基于初投资分摊费用和经营成本的动态费用分析法对不同烟气流速下对流受热面的换热进行经济性分析。计算结果表明,最佳工况比空气燃烧方式下的烟道更加紧凑,但是流速超过一定范围之后带来的引风机耗电量的增加超过了流速增加所带来的强化换热的收益,因此是不经济的。采用动态费用法为富氧燃烧方式下对流受热面最佳流速的选择提供依据,对新型富氧燃烧锅炉换热器的设计具有一定的指导意义。

Reduction in the amount of flue gas and fuel due to higher boiler thermal efficiency under oxygen-rieh atmosphere results in dust decrease in the exhaust gas, which makes it possible to improve flue gas velocity for utility boilers. However, though flue gas velocity increasing may strengthen heat transfer, the power consumption of induced fans would also increase at the same time. The dynamic cost method based on initial investment and operation cost was used to conduct economy analysis for heating surfaces at different flue gas velocities. The results indicated that the flue was more compact under the optimal working condition than at the air cond3ustion mode. However, when the flue gas velocity exceeded some limit, the increase in power consumption of the induced fan would exceed the profit obtained from heat transfer strengthening.