Overall economical performance of 1 000 MW class ultra-supercritical unit with double-reheat cycle

By analyzing the factors affecting the economical performance of 1 000 MW class ultra-supercritical double-reheat units, combing with the case study on economical performance difference between the single-reheat units and double-reheat units, the actual performance of the double-reheat units was evaluated according to the performance acceptance test results of sample units. The results show that, as a result of series of optimizations to the regenerative system design, pipe pressure drop reduction, flue gas heat recovery, boiler efficiency enhancement and auxiliary power ratio reduction (besides the advantages of thermal cycle and parameters), the in-service 1 000 MW class ultra-supercritical double-reheat units' design coal consumption rate is 5.7% lower than that of the same scale single-reheat units. The application of double-reheat cycle, steam parameters improvement and regenerative system optimization greatly reduces the unit's heat rate, which is the major reason for overall performance improvement of the double-reheat units. The overall economical performance of domestic in-service 1 000 MW class double-reheat units meets the design requirement, and has achieved the best level of coal-fired units at present.