Abstract:

Aiming at the NO _x removal efficiency and microbial community structure change of chemical absorption-biological reduction integrated system (CABR) cooperated with the adjusting NO _x oxidation ratio under different oxygen volume frations, the effect mechanism of oxygen on the CABR system was studied. Results showed that when the NO _x oxidation ratio in the simulated flue gas was adjusted to 50% and the oxygen volume fration in the flue gas was in the range of 0—8%, the NO _x removal efficiency of CABR system was stable above 99%. When the oxygen volume fration reached 10%, the denitration efficiency of the system could still exceed 94%. The detection of EPS content showed that when the oxygen volume fration increased from 0 to 5%, the PN/PS value in LB-EPS increased from 1.72 to 2.18, and the PN/PS value in TB-EPS decreased from 1.21 to 0.706. High-throughput sequencing results indicated that Proteobacteria was the dominant phylum under different oxygen volume frations, and its relative abundance reached 55.0%—85.7%. Proteobacteria was a typical phylum with aerobic denitrification capacity, which ensured the stability of denitration performance of the system. In conclusion, the oxygen volume fration had little influence on the denitration effect of the CABR method cooperated with adjusting NO _x oxidation ratio, which provided a new idea for the removal of NO _x in the flue gas.

Key words: nitrogen oxides, O₂ volume fration, NO _x oxidation ratio, chemical absorption-biological reduction, microbial community analysis

摘要：

针对调节NO _x 氧化度协同化学吸收-生物还原法在不同氧气体积分数下的NO _x 去除性能及微生物群落结构的动态变化，研究了氧气体积分数对该体系的影响机制。结果表明，调节模拟烟气中NO _x 氧化度为50%时，烟气中包含的氧气体积分数在0~8%的范围内，化学吸收-生物还原（CABR）体系的脱硝效率稳定在99%以上；当氧气体积分数达到10%时，系统脱硝效率仍可超过94%。EPS含量检测显示，氧体积分数从0增加至5%，导致LB-EPS中PN/PS值由1.72上升到2.18，TB-EPS中PN/PS值从1.21降至0.706。高通量测序结果表明，不同氧气体积分数下微生物的优势菌门均为Proteobacteria，其相对丰度达到55.0%~85.7%，它是典型的具有好氧反硝化能力的菌门，这保证了该系统脱硝性能的稳定。综上所述，氧体积分数对调节NO _x 氧化度协同CABR集成系统的脱硝效果影响较小，为烟气中NO _x 的去除提供了新的思路。

关键词: 氮氧化物, O₂体积分数, NO _x 氧化度, 化学吸收-生物还原, 微生物群落分析