Fe（II）/γ-Al2O3 powders synthesized using the dipping method were produced from a mixed aqueous solution containing aluminium oxide （γ-Al2O3） and iron（II）-precursor （FeSO4）, and used for photoFenton degradati...Fe（II）/γ-Al2O3 powders synthesized using the dipping method were produced from a mixed aqueous solution containing aluminium oxide （γ-Al2O3） and iron（II）-precursor （FeSO4）, and used for photoFenton degradation of phthalocyanine dyes （PCs） under ultraviolet （UV） irradiation in an up-flow fluidized bed. The catalysts were characterized by XRD, ESCA, BET, EDS and SEM. The results showed that Fe2＋ ion was compounded on the γ-Al2O3 carder. The effects of different reaction parameters such as catalyst activity, dosage and solution pH on the decolorization of PCs were assessed. Results indicated that maximum decolorization （more than 95%） of PCs occurred with 20 wt% Fe（II）/γ-Al2O3 catalyst （dosage of 60 g/L） using a combination of UV irradiation and heterogeneous Fenton system. The degradation efficiency of PCs increases as pH decreases, exhibiting a maximum efficiency at pH 3.5. The recycled catalyst was capable of repeating three runs without a significant decrease in treatment efficiency, and this demonstrated the stability and reusability of catalyst.展开更多
The work is devoted to the study of combustion of brown coal,pine sawdust,and their mixtures in a fluidized bed of catalyst at 600-750℃.It is shown that an increase in the content of sawdust in a mixture with brown c...The work is devoted to the study of combustion of brown coal,pine sawdust,and their mixtures in a fluidized bed of catalyst at 600-750℃.It is shown that an increase in the content of sawdust in a mixture with brown coal leads to an increase in the burnout degree of solid fuel from 94.4%to 99.9%,while the emission of greenhouse gases in the form of CO_(2)CO and NOxis reduced(CO_(2)from the biomass is not included in the balance).The high content of alkaline earth metal oxides(CaO and MgO)in the mineral part of brown coal,sawdust,and their mixtures eliminates the emission of sulfur oxides and the slagging of heat-exchange surfaces during the combustion in a fluidized bed of catalyst.The optimal temperature,when the highest burnout degree of the above fuels is achieved in the combustion is 750℃.It is also shown that the increase in temperature and the content of sawdust in the composition of the fuel mixtures has a positive effect on the economic and environmental process indicators.展开更多
Waste fluidized catalytic cracking(FCC)catalysts contain strategic metals with high recycling value,and eff ective treatment of these waste catalysts is crucial for resource recovery and environmental protection.In th...Waste fluidized catalytic cracking(FCC)catalysts contain strategic metals with high recycling value,and eff ective treatment of these waste catalysts is crucial for resource recovery and environmental protection.In this study,a leaching process of“oxidation treatment–alkali roasting–wet mill leaching”was proposed for the extraction of tungsten(W)and molybdenum(Mo)valuable metals from spent FCC catalysts,and a technological pathway suitable for industrial production was explored through a detailed investigation of the conversion mechanism and process optimization.After the pretreatment by oxidation and roasting at 600℃for 4 h,the optimal conditions for alkali roasting were found to be 950℃with the addition of three times the theoretical amount of alkali(Na_(2)CO_(3)),which ensured full conversion and avoided the generation of impurities.Through one-factor exploration and response surface optimization,the average leaching rate for W and Mo reached 87.23%and 99.50%,respectively,under the wet mill leaching conditions of a 200-mesh particle size,liquid–solid ratio of 2.79,a wet milling time of 1.18 h,a pellet ratio of 6.44:1,and a roasting time of 114.61 min.It was observed that both heating leaching and wet mill leaching could achieve full extraction with a relatively small liquid–solid ratio,thereby minimizing the production and discharge of waste liquid.The formation of nickel tungstate(NiWO_(4))was identified as the main factor limiting the leaching of W,and it was found that increasing the oxygen content during the roasting process could improve the leaching efficiency.This study provides practical guidance and a scientific basis for the environmentally friendly and resource-efficient utilization of spent FCC catalysts.展开更多
The fluidized-bed polymerization process has been in use for decades. From the manufacturer＇s perspective it is desirable to improve technology without major modification of the reactor system. Therefore, in order to...The fluidized-bed polymerization process has been in use for decades. From the manufacturer＇s perspective it is desirable to improve technology without major modification of the reactor system. Therefore, in order to meet the demand for new products or more efficient reactor operation, manufacturers prefer to improve the catalyst system in the most cost effective manner. Using polypropylene production as an example, some recent advances in fluidized-bed polymerization technology are presented.展开更多
To investigate the gas-solid flow pattern of a combustor-style fluid catalytic cracking regenerator, a laboratory-scale regenerator was designed. In scaling down from an actual regenerator, large-diameter hydrodynamic...To investigate the gas-solid flow pattern of a combustor-style fluid catalytic cracking regenerator, a laboratory-scale regenerator was designed. In scaling down from an actual regenerator, large-diameter hydrodynamic effects were taken into consideration. These considerations are the novelties of the present study. Applying the Eulerian-Eulerian approach, a three-dimensional computational fluid dynamics （CFD） model of the regenerator was developed. Using this model, various aspects of the hydrodynamic behavior that are potentially effective in catalyst regeneration were investigated. The CFD simulation results show that at various sections the gas-solid flow patterns exhibit different behavior because of the asymmetric location of the catalyst inlets and the lift outlets. The ratio of the recirculated catalyst to spent catalyst determines the quality of the spent and recirculated catalyst mixing and distribution because the location and quality of vortices change in the lower part of the combustor. The simulation results show that recirculated catalyst considerably reduces the air bypass that disperses the catalyst particles widely over the cross section. Decreasing the velocity of superficial air produces a complex flow pattern whereas the variation in catalyst mass flux does not alter the flow pattern significantly as the flow is dilute.展开更多
文摘Fe（II）/γ-Al2O3 powders synthesized using the dipping method were produced from a mixed aqueous solution containing aluminium oxide （γ-Al2O3） and iron（II）-precursor （FeSO4）, and used for photoFenton degradation of phthalocyanine dyes （PCs） under ultraviolet （UV） irradiation in an up-flow fluidized bed. The catalysts were characterized by XRD, ESCA, BET, EDS and SEM. The results showed that Fe2＋ ion was compounded on the γ-Al2O3 carder. The effects of different reaction parameters such as catalyst activity, dosage and solution pH on the decolorization of PCs were assessed. Results indicated that maximum decolorization （more than 95%） of PCs occurred with 20 wt% Fe（II）/γ-Al2O3 catalyst （dosage of 60 g/L） using a combination of UV irradiation and heterogeneous Fenton system. The degradation efficiency of PCs increases as pH decreases, exhibiting a maximum efficiency at pH 3.5. The recycled catalyst was capable of repeating three runs without a significant decrease in treatment efficiency, and this demonstrated the stability and reusability of catalyst.
基金funded by the Ministry of Science and Higher Education of the Russian Federation,within the governmental order for the Boreskov Institute of Catalysis(project AAAA-A21-121011390007-7)The economic assessment and Environmental impact calculation were performed as part of the Tyumen University state assignment[project No.FEWZ2021–0014(Scientific and technical foundations and applied solutions for integrated energy and thermal processing of biomass to ensure environmentally friendly technologies in energy industry and metallurgy)]。
文摘The work is devoted to the study of combustion of brown coal,pine sawdust,and their mixtures in a fluidized bed of catalyst at 600-750℃.It is shown that an increase in the content of sawdust in a mixture with brown coal leads to an increase in the burnout degree of solid fuel from 94.4%to 99.9%,while the emission of greenhouse gases in the form of CO_(2)CO and NOxis reduced(CO_(2)from the biomass is not included in the balance).The high content of alkaline earth metal oxides(CaO and MgO)in the mineral part of brown coal,sawdust,and their mixtures eliminates the emission of sulfur oxides and the slagging of heat-exchange surfaces during the combustion in a fluidized bed of catalyst.The optimal temperature,when the highest burnout degree of the above fuels is achieved in the combustion is 750℃.It is also shown that the increase in temperature and the content of sawdust in the composition of the fuel mixtures has a positive effect on the economic and environmental process indicators.
基金financially supported by the Young Elite Scientists Sponsorship Program by the Beijing Association for Science and Technology(No.BYESS2023070)Major R&D special projects in Yichun City(No.40009016202301)the Horizontal project of Jiangxi Minmetals Gao'an Non-ferrous Metal Co.,Ltd.(No.40053001202430)。
文摘Waste fluidized catalytic cracking(FCC)catalysts contain strategic metals with high recycling value,and eff ective treatment of these waste catalysts is crucial for resource recovery and environmental protection.In this study,a leaching process of“oxidation treatment–alkali roasting–wet mill leaching”was proposed for the extraction of tungsten(W)and molybdenum(Mo)valuable metals from spent FCC catalysts,and a technological pathway suitable for industrial production was explored through a detailed investigation of the conversion mechanism and process optimization.After the pretreatment by oxidation and roasting at 600℃for 4 h,the optimal conditions for alkali roasting were found to be 950℃with the addition of three times the theoretical amount of alkali(Na_(2)CO_(3)),which ensured full conversion and avoided the generation of impurities.Through one-factor exploration and response surface optimization,the average leaching rate for W and Mo reached 87.23%and 99.50%,respectively,under the wet mill leaching conditions of a 200-mesh particle size,liquid–solid ratio of 2.79,a wet milling time of 1.18 h,a pellet ratio of 6.44:1,and a roasting time of 114.61 min.It was observed that both heating leaching and wet mill leaching could achieve full extraction with a relatively small liquid–solid ratio,thereby minimizing the production and discharge of waste liquid.The formation of nickel tungstate(NiWO_(4))was identified as the main factor limiting the leaching of W,and it was found that increasing the oxygen content during the roasting process could improve the leaching efficiency.This study provides practical guidance and a scientific basis for the environmentally friendly and resource-efficient utilization of spent FCC catalysts.
文摘The fluidized-bed polymerization process has been in use for decades. From the manufacturer＇s perspective it is desirable to improve technology without major modification of the reactor system. Therefore, in order to meet the demand for new products or more efficient reactor operation, manufacturers prefer to improve the catalyst system in the most cost effective manner. Using polypropylene production as an example, some recent advances in fluidized-bed polymerization technology are presented.
文摘To investigate the gas-solid flow pattern of a combustor-style fluid catalytic cracking regenerator, a laboratory-scale regenerator was designed. In scaling down from an actual regenerator, large-diameter hydrodynamic effects were taken into consideration. These considerations are the novelties of the present study. Applying the Eulerian-Eulerian approach, a three-dimensional computational fluid dynamics （CFD） model of the regenerator was developed. Using this model, various aspects of the hydrodynamic behavior that are potentially effective in catalyst regeneration were investigated. The CFD simulation results show that at various sections the gas-solid flow patterns exhibit different behavior because of the asymmetric location of the catalyst inlets and the lift outlets. The ratio of the recirculated catalyst to spent catalyst determines the quality of the spent and recirculated catalyst mixing and distribution because the location and quality of vortices change in the lower part of the combustor. The simulation results show that recirculated catalyst considerably reduces the air bypass that disperses the catalyst particles widely over the cross section. Decreasing the velocity of superficial air produces a complex flow pattern whereas the variation in catalyst mass flux does not alter the flow pattern significantly as the flow is dilute.
