Study on flue gas waste heat utilization system optimization of a new 1000MW unit

In this paper, the flue gas waste heat utilization system in a new 1000MW unit was as the research object, and the numerical simulations on the flue flow field and resistance characteristics of the low-temperature economizer for four operating conditions without guiding device or with three kind guiding devices was carried out by computational fluid dynamics software, and the correctness of the numerical simulation result was verified by the guaranteed value of the low-temperature economizer manufacturer. The results show that: The simulation result was basically consistent with the guaranteed value of the low-temperature economizer manufacturer, which was shown the correctness of the simulation calculation; the flue gas flow of low-temperature economizer without guiding device was unevenly distributed, with high-speed area and ash prone area; the additional guiding devices can reduce the inlet deflection angle of the low-temperature economizer, which can effectively reduce the speed deviation and improve the flow field distribution; The effect of flow equalization and resistance characteristics of the guiding devices first decreases and then increases with the number of guiding devices; The unreasonable selection of the number and position of the guiding devices will cause the flue gas to rush on the flue and cause the risk of flue vibration. In order to promote the realization of the transformation purpose, the improvement effect of the guiding devices should be simulated and calculated before the transformation.