Currently,as environmental pollution becomes increasingly severe,flue gas denitrification has emerged as a significant area of research.With the advancement of modern industry and the improvement of living standards,a...Currently,as environmental pollution becomes increasingly severe,flue gas denitrification has emerged as a significant area of research.With the advancement of modern industry and the improvement of living standards,air pollution has gained growing attention.Sulfur dioxide and nitrogen oxides(NO_(x))have become major contributors to air pollution,posing serious harm to the environment.Consequently,flue gas desulfurization and denitrification technologies have become key research focuses in industrial development.This paper explores the selection of agricultural waste carbon sources and their pretreatment methods.It provides an in-depth analysis of the significance of agricultural waste carbon sources in flue gas denitrification,focusing on their performance and mechanisms.The study also discusses the role of agricultural waste carbon sources in flue gas denitrification,aiming to offer new research perspectives for relevant stakeholders.展开更多
To improve the denitrification performance of carbon-based materials for sintering flue gas,we prepared a composite catalyst comprising coconut shell activated carbon(AC)modified by thermal oxidation air.The microstru...To improve the denitrification performance of carbon-based materials for sintering flue gas,we prepared a composite catalyst comprising coconut shell activated carbon(AC)modified by thermal oxidation air.The microstructure,the specific surface area,the pore volume,the crystal structure,and functional groups presented in the prepared Cu2O/AC catalysts were thoroughly characterized.By using scanning electron microscopy(SEM),nitrogen adsorption/desorption isotherms,Fourier-transform infrared(FTIR)spectroscopy and X-ray diffractometry(XRD),the effects of Cu2O loading and calcination temperature on Cu2O/AC catalysts were investigated at low temperature(150℃).The research shows that Cu on the Cu2O/AC catalyst is in the form of Cu2O with good crystalline performance and is spherical and uniformly dispersed on the AC surface.The loading of Cu2O increases the active sites and the specific surface area of the reaction gas contact,which is conducive to the rapid progress of the carbon monoxide selective catalytic reduction(CO-SCR)reaction.When the loading of Cu2O was 8%and the calcination temperature was 500℃,the removal rate of NOx facilitated by the Cu2O/AC catalyst reached 97.9%.These findings provide a theoretical basis for understanding the denitrification of sintering flue gas.展开更多
In accordance with the cerium-lanthanum ratio of fluorocerium ores in the mineralogy of the Baiyun Ebo process, the (Ce,La)CO<sub>3</sub>F grains were synthesised by hydrothermal method using pure material...In accordance with the cerium-lanthanum ratio of fluorocerium ores in the mineralogy of the Baiyun Ebo process, the (Ce,La)CO<sub>3</sub>F grains were synthesised by hydrothermal method using pure material to simulate bastnaesite minerals, and used as NH<sub>3</sub>-SCR denitrification catalysts. The activity results showed that the synthetic (Ce,La)CO<sub>3</sub>F was roasted at 500<span><span><span style="font-family:;" "=""><span style="white-space:nowrap;">˚</span>C</span></span></span><span><span><span style="font-family:;" "="">, and the NOx conversion was 27% at 200</span></span></span><span><span><span style="font-family:;" "=""><span style="white-space:nowrap;">˚</span>C</span></span></span><span><span><span style="font-family:;" "="">. The NH<sub>3</sub></span></span></span><span><span><span style="font-family:;" "="">-</span></span></span><span><span><span style="font-family:;" "="">SCR catalytic activity of the synthesised (Ce,La)CO<sub>3</sub>F was improved by loaded transition metal Mn. The best catalyst was found to be produced by impregnating (Ce,La)CO<sub>3</sub>F with 1 mol/L manganese nitrate solution, with a NOx conversion of 80% at 250</span></span></span><span><span><span style="font-family:;" "=""><span style="white-space:nowrap;">˚</span>C</span></span></span><span><span><span style="font-family:;" "="">. The loading of Mn resulted in the appearance of numerous well-dispersed MnOx species on the catalyst surface, the dispersion of Ce<sub>7</sub>O<sub>12</sub> species was also greatly enhanced, and the reduction in grain size indicated that Mn<sup>n+</sup> entered into the (Ce,La)CO<sub>3</sub>F lattice causing lattice shrinkage. The number of acidic sites on the catalyst surface and the redox capacity were enhanced. The amount of Ce<sup>3+</sup> in the catalyst was also enhanced by the introduction of Mn<sup>n+</sup>, but the proportion of adsorbed oxygen decreased, which indicated that the introduction of Mn<sup>n+</sup> was detrimental to the increase in the proportion of adsorbed oxygen. The reaction mechanisms of the (Ce,La)CO<sub>3</sub>F and Mn/(Ce,La)CO<sub>3</sub>F catalysts were investigated by <i>in-situ</i> Fourier transform infrared spectroscopy (FTIR). The results showed that catalysts followed the E-R and L-H mechanisms. When loaded with Mn, the main reactive species in the L-H mechanism were the </span></span></span><span><span><span style="font-family:;" "=""><span></span></span></span></span><span><span><span style="font-family:;" "=""><span> </span>(ad) species on the Br<span style="white-space:nowrap;">ø</span>nsted acidic site and the O-Ce<sup>3+</sup>-O-NO, O-Mn<sup>3+</sup>-O-NO species. The main reactive species for the E-R mechanism were NH<sub>3</sub>/</span></span></span><span><span><span style="font-family:;" "=""><span></span></span></span></span><span><span><span style="font-family:;" "=""><span> </span>(ad) species and NO. The </span></span></span><span><span><span style="font-family:;" "=""><span></span></span></span></span><span><span><span style="font-family:;" "=""><span> </span>(ad) species on the Br<span style="white-space:nowrap;">ø</span>nsted acidic sites act as the main reactive NH3</span></span></span><span><span><sub><span style="font-family:;" "=""> </span></sub></span></span><span><span><span style="font-family:;" "="">(g) adsorbing species, bonded to the Ce<sup>4+</sup> in the carrier (Ce,La)CO<sub>3</sub>F to participate in the acid cycle reaction. The introduction of Mn<sup>n+</sup> increases the number of Br<span style="white-space:nowrap;">ø</span>nsted acidic sites on the catalyst surface, and acts as an adsorption site for NO, to react with NO to generate more monodentate nitrate species, to participate in the redox cycle reactions. The above results indicated that Mn<sup>n+</sup> and (Ce,La)CO<sub>3</sub>F have a good mutual promotion effect, which makes the loaded catalyst have excellent performance, which provides a theoretical basis for the high value utilization of bastnaesite</span></span></span><span><span><span style="font-family:;" "="">.</span></span></span>展开更多
文摘Currently,as environmental pollution becomes increasingly severe,flue gas denitrification has emerged as a significant area of research.With the advancement of modern industry and the improvement of living standards,air pollution has gained growing attention.Sulfur dioxide and nitrogen oxides(NO_(x))have become major contributors to air pollution,posing serious harm to the environment.Consequently,flue gas desulfurization and denitrification technologies have become key research focuses in industrial development.This paper explores the selection of agricultural waste carbon sources and their pretreatment methods.It provides an in-depth analysis of the significance of agricultural waste carbon sources in flue gas denitrification,focusing on their performance and mechanisms.The study also discusses the role of agricultural waste carbon sources in flue gas denitrification,aiming to offer new research perspectives for relevant stakeholders.
基金Open Fund of Key Laboratory of Ministry of Education for Metallurgical Emission Reduction and Comprehensive Utilization of Resources,China(No.JKF19-08)General Project of Science and Technology Plan of Yunnan Science and Technology Department,China(No.2019FB077)+1 种基金Industrialization Cultivation Project of Scientific Research Fund of Yunnan Provincial Department of Education,China(No.2016CYH07)Top Young Talents of Yunnan Ten Thousand Talents Plan,China(No.YNWR-QNBJ-2019-263)。
文摘To improve the denitrification performance of carbon-based materials for sintering flue gas,we prepared a composite catalyst comprising coconut shell activated carbon(AC)modified by thermal oxidation air.The microstructure,the specific surface area,the pore volume,the crystal structure,and functional groups presented in the prepared Cu2O/AC catalysts were thoroughly characterized.By using scanning electron microscopy(SEM),nitrogen adsorption/desorption isotherms,Fourier-transform infrared(FTIR)spectroscopy and X-ray diffractometry(XRD),the effects of Cu2O loading and calcination temperature on Cu2O/AC catalysts were investigated at low temperature(150℃).The research shows that Cu on the Cu2O/AC catalyst is in the form of Cu2O with good crystalline performance and is spherical and uniformly dispersed on the AC surface.The loading of Cu2O increases the active sites and the specific surface area of the reaction gas contact,which is conducive to the rapid progress of the carbon monoxide selective catalytic reduction(CO-SCR)reaction.When the loading of Cu2O was 8%and the calcination temperature was 500℃,the removal rate of NOx facilitated by the Cu2O/AC catalyst reached 97.9%.These findings provide a theoretical basis for understanding the denitrification of sintering flue gas.
文摘In accordance with the cerium-lanthanum ratio of fluorocerium ores in the mineralogy of the Baiyun Ebo process, the (Ce,La)CO<sub>3</sub>F grains were synthesised by hydrothermal method using pure material to simulate bastnaesite minerals, and used as NH<sub>3</sub>-SCR denitrification catalysts. The activity results showed that the synthetic (Ce,La)CO<sub>3</sub>F was roasted at 500<span><span><span style="font-family:;" "=""><span style="white-space:nowrap;">˚</span>C</span></span></span><span><span><span style="font-family:;" "="">, and the NOx conversion was 27% at 200</span></span></span><span><span><span style="font-family:;" "=""><span style="white-space:nowrap;">˚</span>C</span></span></span><span><span><span style="font-family:;" "="">. The NH<sub>3</sub></span></span></span><span><span><span style="font-family:;" "="">-</span></span></span><span><span><span style="font-family:;" "="">SCR catalytic activity of the synthesised (Ce,La)CO<sub>3</sub>F was improved by loaded transition metal Mn. The best catalyst was found to be produced by impregnating (Ce,La)CO<sub>3</sub>F with 1 mol/L manganese nitrate solution, with a NOx conversion of 80% at 250</span></span></span><span><span><span style="font-family:;" "=""><span style="white-space:nowrap;">˚</span>C</span></span></span><span><span><span style="font-family:;" "="">. The loading of Mn resulted in the appearance of numerous well-dispersed MnOx species on the catalyst surface, the dispersion of Ce<sub>7</sub>O<sub>12</sub> species was also greatly enhanced, and the reduction in grain size indicated that Mn<sup>n+</sup> entered into the (Ce,La)CO<sub>3</sub>F lattice causing lattice shrinkage. The number of acidic sites on the catalyst surface and the redox capacity were enhanced. The amount of Ce<sup>3+</sup> in the catalyst was also enhanced by the introduction of Mn<sup>n+</sup>, but the proportion of adsorbed oxygen decreased, which indicated that the introduction of Mn<sup>n+</sup> was detrimental to the increase in the proportion of adsorbed oxygen. The reaction mechanisms of the (Ce,La)CO<sub>3</sub>F and Mn/(Ce,La)CO<sub>3</sub>F catalysts were investigated by <i>in-situ</i> Fourier transform infrared spectroscopy (FTIR). The results showed that catalysts followed the E-R and L-H mechanisms. When loaded with Mn, the main reactive species in the L-H mechanism were the </span></span></span><span><span><span style="font-family:;" "=""><span></span></span></span></span><span><span><span style="font-family:;" "=""><span> </span>(ad) species on the Br<span style="white-space:nowrap;">ø</span>nsted acidic site and the O-Ce<sup>3+</sup>-O-NO, O-Mn<sup>3+</sup>-O-NO species. The main reactive species for the E-R mechanism were NH<sub>3</sub>/</span></span></span><span><span><span style="font-family:;" "=""><span></span></span></span></span><span><span><span style="font-family:;" "=""><span> </span>(ad) species and NO. The </span></span></span><span><span><span style="font-family:;" "=""><span></span></span></span></span><span><span><span style="font-family:;" "=""><span> </span>(ad) species on the Br<span style="white-space:nowrap;">ø</span>nsted acidic sites act as the main reactive NH3</span></span></span><span><span><sub><span style="font-family:;" "=""> </span></sub></span></span><span><span><span style="font-family:;" "="">(g) adsorbing species, bonded to the Ce<sup>4+</sup> in the carrier (Ce,La)CO<sub>3</sub>F to participate in the acid cycle reaction. The introduction of Mn<sup>n+</sup> increases the number of Br<span style="white-space:nowrap;">ø</span>nsted acidic sites on the catalyst surface, and acts as an adsorption site for NO, to react with NO to generate more monodentate nitrate species, to participate in the redox cycle reactions. The above results indicated that Mn<sup>n+</sup> and (Ce,La)CO<sub>3</sub>F have a good mutual promotion effect, which makes the loaded catalyst have excellent performance, which provides a theoretical basis for the high value utilization of bastnaesite</span></span></span><span><span><span style="font-family:;" "="">.</span></span></span>
