The post-combustion technology of circulating fluidized beds (CFBs) can largely reduce the emission of nitrogen oxides (NOx) in the process of combustion, significantly reducing the removal cost of NOx. To explore the potential of the combined removal of NOx and SO2 emissions under post-combustion technology, experiments were conducted on a 0.1 MWth circulating fluidized bed test platform. This paper focuses on the effect of temperature in CFB with limestone addition on NOx and SO2 emissions under post-combustion technology combined with sorbent injection into the furnace. The low-cost combined removal of NOx and SO2 can be realized by denitrification in the furnace and through secondary desulfurization in the furnace and post-combustion chamber. In the optimized experimental condition, with combustion temperatures at 845 ◦C and sorbent addition in the furnace under post-combustion, the emission of NOx can be reduced to 47.10 mg/Nm3(@6%O2), and meanwhile, the emission of SO2 can be reduced to 92.09 mg/Nm3. Sulfur removal efficiency is higher under lower temperatures in a weakly reducing atmosphere. The reaction of sulfur fixation occurred in the post-combustion chamber and caused the particle size of fly ashes at the tail flue to become bigger and the sulfur content in the fly ash at the tail flue to increase. At 845–905 ◦C, the combustion temperature had a bigger effect on the SO2 emission than the NOx with sorbent addition in the furnace under post-combustion.
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