厌氧氨氧化烟气脱硝工艺的探讨

摘要

Traditional biological flue gas denitrification process which is mainly based on denitrification has advantages of high removal efficiency,simple equipment,low running cost and so on. However,this process needs adding additional electron donors which may increase the running cost. Besides,this process may release greenhouse gas like nitrous oxide. New biological flue gas denitrification process based on anaerobic ammonia oxidation (Anammox) can solve the above problems. In this review,according to the nitrogen cycle,nitrogen gas is the same end products by denitrification and Anammox,which means Anammox might be also used for the removal of nitric oxide in flue gas. Referring to metabolism model of Anammox reaction,the possibility of treating with flue gas using Anammox process was discussed and partly proved by some studies. Considering mass transfer and biological reaction,the feasible pathway and some key questions were presented and analyzed. This review pointed out that nitric oxide can react with ammonium to form the product hydrazine. Then,hydrazine can be hydrolyzed to nitrogen gas. All these steps above can happen in Anammox reaction, which can be used to remove nitric oxide in flue gas. Considering the huge amount of flue gas,the possible pathway to treat with nitric oxide in flue gas is using chemical absorption that nitric oxide can be absorbed and transferred into liquid phase. Then,nitric oxide can be converted to nitrogen gas by Anammox reaction. The key questions that removing nitric oxide in flue gas by Anammox process include process of chemical absorption and culturing of microorganisms. The chemical absorption includes selection and regeneration of absorbents. The culturing of microorganisms includes the symbiosis of microbial community.%以反硝化作用为基础的生物法烟气脱硝工艺具有脱硝效率较高、工艺设备简单、建设运行成本低等优点,但是也存在需要外加电子供体、释放温室气体(一氧化二氮)等问题.以厌氧氨氧化作用为基础开发的新型生物法烟气脱硝工艺有望解决以上问题.本文从氮素循环角度出发,指出了厌氧氨氧化作用和反硝化作用在生物脱硝方面具有相似性.以厌氧氨氧化的生化反应模型为依据,探讨了厌氧氨氧化烟气脱硝工艺的可行性,并提供了相应的事实依据.以传质和反应过程为基础,分析了厌氧氨氧化烟气脱硝工艺可能的实现途径和面临的关键问题.文中指出,利用厌氧氨氧化作用可将铵和一氧化氮转化为联氨,联氨进一步分解为氮气,从而实现烟气脱硝.考虑到烟气处理量大的特点,厌氧氨氧化烟气脱硝工艺的实现途径是先通过化学吸收将气相中的一氧化氮转移至液相,而后通过厌氧氨氧化反应实现氮素的脱除.厌氧氨氧化烟气脱硝工艺所面临的关键问题主要是相态转移问题和菌种培养问题,涉及化学吸收剂的选择和再生、脱氮菌群的协同培养等.