Fe(Ⅱ)EDTA吸收-微生物还原体系处理烟气中NO试验  

Evaluation of Fe(Ⅱ)EDTA absorption-biological reduction integrated process on removal of NO from flue gas in lab-scale

作　　者：刘楠[1] 吴成志[1] 刘芸[1] 蔡灵琳[1] 李伟[1,2] 

机构地区：[1]浙江大学环境工程研究所,浙江杭州310027 [2]浙江省工业锅炉炉窑烟气污染控制工程技术研究中心,浙江杭州311202

出　　处：《浙江大学学报（工学版）》2011年第12期2196-2201,共6页Journal of Zhejiang University：Engineering Science

基　　金：国家"863"高技术研究发展计划资助项目(2006AA06Z345)

摘　　要：针对目前烟气脱硝技术的缺陷,采用络合吸收结合生物还原的方法处理烟气中NO,在该过程中,NO与Fe(Ⅱ)EDTA络合,进而由微生物将NO还原为N2;其中烟气中的O2能够迅速氧化吸收NO的活性成分Fe(Ⅱ)EDTA为Fe(Ⅲ)EDTA,而它可被微生物再生为Fe(Ⅱ)EDTA,使络合吸收剂得到有效再生,用以循环利用.在稳态运行条件下,该过程的NO去除率可达90%,而直接生物法仅为29%的去除率,单纯的络合吸收法在相同条件下经过5h的运行,吸收液已无法对NO进行有效的吸收.另外,分离出了能够将Fe(Ⅱ)EDTA-NO中的NO还原为N2的脱氮菌Pseudomonas sp.,以及将Fe(Ⅲ)EDTA还原为Fe(Ⅱ)EDTA的铁还原菌Escherichia coli,并研究了它们对Fe(Ⅱ)EDTA-NO或Fe(Ⅲ)EDTA的还原情况,结果表明其还原率均可达到90%以上.For the current shortcomings of flue gas denitrification technologies, a chemical absorption- biological reduction integrated approach was developed to achieve the NOx removal from the flue gas. In this integrated process, NO is chelated by Fe（ Ⅱ ）EDTA in scrubbing liquid and subsequently reduced to N2 by denitrification bacteria. Fe（ Ⅲ） EDTA formed via oxidation by oxygen in flue gas is simultaneously and biologically reduced back to Fe （ Ⅱ ）EDTA by dedicated iron-reducing bacteria. Thus the absorbent complex can be regenerated effectively for recycling. The possibilities of this process for NO removal were studied. The comparison with NO removal in different ways was investigated in a glass column. The scrubbing and biological regeneration were simultaneously carried out after adapting the microorganisms to the packed tower. And the experiments of Fe（ Ⅱ ）EDTA-NO and Fe（ Ⅱ ）EDTA reduction by bacterium were also studied in 100 mL glass serum vials under anaerobic conditions, which were filled with sterile medium and inoculated with dedicated bacterium strain. During the steady state operation, the integrated approach for the NO removal can be achieved to 90%, in comparison with 29% by the water-based biofilter. Moreover, full breakthrough of NO was observed in the scrubbing process after 5 h of operation at the same condition. Additionally, two dedicated bacterial strains （a Fe （Ⅱ）EDTA-NO reducing bacterium, Pseudomonas sp. and Fe （m）EDTA reducing one, Escherichia coli ） were isolated and characterized. It is investigated that 90% of Fe（Ⅲ ）EDTA and Fe（ Ⅱ ）EDTA-NO can be reduced by these two bacterial strains respectively. Hence, it is possible that the chemical of Fe（ Ⅱ ）EDTA could be regenerated and recycled to the system. Above all, it is positive that this chemical absorption-biological reduction integrated approach is used for NO removal.

关 键 词：NOx 烟气 络合吸收 微生物 Fe(Ⅱ)EDTA 

分 类 号：X703.5[环境科学与工程—环境工程]