采用底渣灰碱-磁改性催化H2O2脱除NO

NO removal of H2O2 catalyzed by bottom ash alkali-magnetic modification

我国作为煤炭大国,燃煤电厂底渣灰的产量一直居高不下,虽然应用领域广泛但利用率却不高,为了提高其利用率,提出一种高效价廉的处理烟气中NO的新技术,达到"以废治污"的目的。采用碱磁改性的工艺制备底渣非均相类Fenton催化剂,在固定床实验平台上进行快速氧化脱除NO实验研究。通过X射线荧光光谱分析仪(XRF),X射线衍射仪(XRD),扫描电子显微镜(SEM),傅氏转换红外线光谱分析仪(FTIR)等表征方法考察碱磁改性过程对于底渣灰的化学成分、晶体结构、微观形貌及表面官能团的影响。实验研究了反应温度、H2O2溶液质量分数、NO体积分数以及是否通入SO2等反应条件对于NO脱除效率的影响,并通过电子顺磁共振技术(ESR)分析了非均相类Fenton体系脱除NO的机理。结果表明:在最佳反应条件(温度为80℃,H2O2为6%,NO为500×10^-6,未通入SO2)下NO的脱除效率达到了86%;碱磁改性后电厂锅炉底渣中铁含量明显提升有利于催化反应的进行;晶体的种类没有发生变化但FeOX的强度升高石英的强度降低利于催化反应;底渣的表面变得更加粗糙多孔,内部FeOX明显暴露出来,增加了与H2O2的接触面积;表面有利官能团含量增多,与实验结果相符合;反应温度、H2O2溶液质量分数、NO体积分数和SO2对NO的脱除有很大的影响;·OH自由基的强氧化作用是类Fenton体系脱除NO的主要原因。

As a large coal-producing country,the production of bottom ash is high in China.Although there are many application areas of bottom ash,the amount of bottom application is very limited.In order to improve its utilization,it proposes a new and efficient technology for treating NO in flue gas,achieving the goal of using waste to treat waste.The heterogeneous Fenton catalyst was prepared by alkali modification process,and NO was removed from the fixed bed reactor.The influence of alkali magnetic modification process on bottom ash was investigated by using X-ray fluorescence spectrometry(XRF),X-ray diffraction(XRD),scanning electron microscopy(SEM) and Fourier transform infrared spectrometry(FTIR).The effects of reaction temperature,H2O2 concentration,NO gas concentration and whether SO2 was introduced on the NO removal efficiency were investigated experimentally,and the mechanism of non-homogeneous Fenton removal of NO was analyzed by ESR.The results show that the removal efficiency of NO can reach 86% under the optimal reaction conditions(T=80 ℃,c(H2O2)=6%,c(NO)=500×10^-6,no SO2).After the alkaline magnetic modification,the iron content in the bottom ash was obviously improved,which is beneficial to the catalytic reaction.The type of crystal did not change,but the strength of FeOX increased,the strength of quartz decreased,which is favorable for the catalytic reaction.The surface of the bottom ash became more rough and porous.The internal FeOX was obviously exposed,increased the contact area with H2O2.The surface favorable functional group content was increased,which is consistent with the experimental results.The reaction temperature,H2O2 solution concentration,NO concentration and SO2 had a great influence on the removal of NO.The strong oxidation of ·OH radical is the main reason for the removal of NO in Fenton-like system.