絡(luò)合吸收—生物還原兩段式煙氣脫硝系統(tǒng)的性能研究與參數(shù)優(yōu)化
發(fā)布時間：2019-06-28 09:38
【摘要】：隨著經(jīng)濟的發(fā)展和物質(zhì)生活水平的不斷提高,人民對環(huán)境質(zhì)量的要求也越來越高。作為大氣主要污染物之一的氮氧化物,會造成包括酸雨、霧霾、臭氧層破壞等在內(nèi)的一系列環(huán)境問題,因此它的治理也日趨得到各級政府的高度重視,國家也為此出臺了一系列政策法規(guī)來限制氮氧化物的排放。針對火電廠大氣污染物的排放,要求新建鍋爐(65t/h以上)的氮氧化物排放濃度不超過100mg/m3。針對工業(yè)鍋爐煙氣的排放,新建鍋爐的氮氧化物排放限值提出了更高的要求,一般地區(qū)要求不高于300 mg/m3(特別地區(qū)要求不高于200 mg/m3)。因此,如何研究并開發(fā)具有脫銷效率高,投資運行費用低的煙氣脫硝技術(shù)一直是我國脫硝技術(shù)研發(fā)需要努力的方向。化學(xué)吸收-生物還原技術(shù)(CABR)是當前很有應(yīng)用前景的生物脫硝技術(shù)。其原理是利用Fe(Ⅱ)EDTA吸收煙氣中的NO,生成含氮絡(luò)合物Fe(Ⅱ)EDTA-NO。生成Fe(Ⅱ)EDTA-NO需要通過脫氮菌將其還原為N2,并實現(xiàn)Fe(Ⅱ)EDTA的再生。由于煙氣中一般含有一定量的氧氣,部分Fe(Ⅱ)EDTA會被氧化為Fe(Ⅲ)EDTA,因此生物還原過程還包括鐵還原菌將Fe(Ⅲ)EDTA還原為Fe(Ⅱ)EDTA�；诠庹諏﹁F還原過程的影響,本文開展了一部分光照對鐵還原菌生物還原過程的影響研究,另外,為了讓CABR技術(shù)能更好地運用于實際生產(chǎn)中,本文建立了一套新型的絡(luò)合吸收-生物還原兩段式脫硝系統(tǒng),并對其掛膜時間和最大處理負荷與傳統(tǒng)的一體式脫硝系統(tǒng)進行了對比研究。最后本文就如何從削減運行成本的角度來對兩段式脫硝系統(tǒng)的運行參數(shù)優(yōu)化進行了探討。主要得到了以下一些結(jié)論:1.對比了光照培養(yǎng)與無光照培養(yǎng)下的Fe(Ⅲ)EDTA生物還原過程,無光照培養(yǎng)下的還原效率和還原速率更高。對造成兩者生物還原效率的差異性的原因進行探究,發(fā)現(xiàn)EDTA降解不是導(dǎo)致光照條件下還原效率下降的主要原因。利用分子生物學(xué)技術(shù)對比研究了兩者的微生物群落結(jié)構(gòu),高通量測序的結(jié)果顯示,無光照和光照培養(yǎng)的菌群有了較大差異;無光照培養(yǎng)下,菌群中的優(yōu)勢菌種中包含三種具有鐵還原能力的菌屬Bacteroides,Klebsiella,Desulfovibrio,三者合計占全部菌群的47.09%。光照條件下,菌群中的優(yōu)勢菌種中只有一種具有鐵還原能力的菌屬Desulfitobacterium,占全部菌群的12.4%。2.采用混合菌對新的絡(luò)合吸收-生物還原兩段式脫硝系統(tǒng)進行掛膜,比傳統(tǒng)的相繼用鐵還原菌和脫氮菌進行掛膜的時間更短。并且,新型的兩段式脫硝體系抗氧氣沖擊能力已大大提升,且在同等煙氣工況下處理負荷有較大提升。對高進氣量下NO脫除效率不高的原因進行分析,確定主要原因是體系中的脫氮菌和鐵還原菌的量不足。3.從削減運行成本的角度對新型的兩段式脫硝系統(tǒng)的運行參數(shù)優(yōu)化,確定葡萄糖采用連續(xù)補加方式優(yōu)于間歇補加方式,可以有效提高NO脫除效率,降低體系運行成本;系統(tǒng)在初始Fe(Ⅲ)EDTA濃度高于4mM的情況下,出口NO的濃度可以維持在40ppm以下;降低初始Fe(Ⅲ)EDTA濃度可以減小Na2EDTA的損耗速率,從而降低為補充Na2EDTA損耗所需的運行成本。
[Abstract]:With the development of economy and the improvement of the level of material life, the people's demand for environmental quality is getting higher and higher. As one of the main pollutants in the atmosphere, the nitrogen oxide can cause a series of environmental problems, including acid rain, haze, ozone layer destruction, etc., and therefore, it has become more and more highly valued by the governments at all levels. The state has also introduced a series of policies and regulations to limit the discharge of nitrogen oxides. For the discharge of atmospheric pollutants in the thermal power plant, the nitrogen oxide emission concentration of the new boiler (above 65t/ h) is required to not exceed 100 mg/ m3. In the light of the emission of the flue gas of the industrial boiler, the nitrogen oxide emission limit of the new boiler is higher, and the requirements of the general area are not higher than 300 mg/ m3 (the requirements of the special area are not higher than 200 mg/ m3). Therefore, how to study and develop the flue gas denitration technology with the high efficiency of removing the pin and the low cost of the investment operation has been the direction of the research and development of the denitration technology in China. Chemical absorption-bioreduction technology (CABR) is a promising bio-denitrification technology. The principle of the invention is to utilize the Fe (II) EDTA to absorb the NO in the flue gas to generate the nitrogen-containing complex Fe (II) EDTA-NO. The generation of Fe (鈪，
本文編號：2507193
[Abstract]:With the development of economy and the improvement of the level of material life, the people's demand for environmental quality is getting higher and higher. As one of the main pollutants in the atmosphere, the nitrogen oxide can cause a series of environmental problems, including acid rain, haze, ozone layer destruction, etc., and therefore, it has become more and more highly valued by the governments at all levels. The state has also introduced a series of policies and regulations to limit the discharge of nitrogen oxides. For the discharge of atmospheric pollutants in the thermal power plant, the nitrogen oxide emission concentration of the new boiler (above 65t/ h) is required to not exceed 100 mg/ m3. In the light of the emission of the flue gas of the industrial boiler, the nitrogen oxide emission limit of the new boiler is higher, and the requirements of the general area are not higher than 300 mg/ m3 (the requirements of the special area are not higher than 200 mg/ m3). Therefore, how to study and develop the flue gas denitration technology with the high efficiency of removing the pin and the low cost of the investment operation has been the direction of the research and development of the denitration technology in China. Chemical absorption-bioreduction technology (CABR) is a promising bio-denitrification technology. The principle of the invention is to utilize the Fe (II) EDTA to absorb the NO in the flue gas to generate the nitrogen-containing complex Fe (II) EDTA-NO. The generation of Fe (鈪，
本文編號：2507193
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