The effect of different binders on light hydrocarbon aromatization performance of the HZSM-5 catalyst was investigated. Physicochemical properties of the catalysts, such as the specific surface area, pore volume and a...The effect of different binders on light hydrocarbon aromatization performance of the HZSM-5 catalyst was investigated. Physicochemical properties of the catalysts, such as the specific surface area, pore volume and acidity, etc., were characterized to correlate with their aromatization performance data. The results showed that the pore structure of Al2O3 could significantly affect the catalyst performance. As the accessible pore diameter of the catalyst increased from 8.0 nm to 9.0 nm, the light aromatics yield increased by 2.7 percentage points, while the operating time of the catalyst nearly doubled. In addition, catalysts prepared with SiO2 and aluminum phosphate was more active and stable than that prepared with Al2O3, of which the light aromatics yield enhanced 6---8 percentage points and the rtm length, or seivice eife run length nearly doubled.展开更多
Currently,the conversion of waste plastics into high-value products via catalytic pyrolysis enables the advancement of plastics’open-loop recycling.However,enhancing selectivity remains a critical challenge.This stud...Currently,the conversion of waste plastics into high-value products via catalytic pyrolysis enables the advancement of plastics’open-loop recycling.However,enhancing selectivity remains a critical challenge.This study introduces a novel approach to catalytic pyrolysis,utilizing a combination of MCM-41 and modified gallium-based HZSM-5 catalysts,to achieve exceptional selectivity for aromatic liquid-phase products from linear low-density polyethylene.Firstly,to enhance the probability of dehydroaromatization optimization,the type and proportion of metal active sites within the HZSM-5 catalyst are fine-tuned,which would establish equilibrium with acid sites,resulting in a remarkable 15.72%increase in the selectivity of aromatic hydrocarbons.Secondly,to enhance the accessibility of volatiles to active sites,mesoporous MCM-41 with cracking capabilities is introduced.The doping ratio of MCM-41 is meticulously controlled to facilitate the diffusion of cracked volatiles to the active centers of modified gallium-based HZSM-5,enabling efficient reforming reactions.Experimental findings demonstrate that MCM-41 significantly enhances the dehydroaromatization activity of the modified gallium-based HZSM-5 catalyst.Under the influence of MCM-41:Zr_(2)Ga_(3)/HZSM-5=1:2 catalyst,the selectivity for aromatic hydrocarbons reaches an impressive 93.11%,with a notable 60.01%selectivity for benzene,toluene,ethylbenzene,and xylene.Lastly,this study proposes a plausible pathway for the generation of high-value aromatic hydrocarbons using the combined catalyst.展开更多
文摘The effect of different binders on light hydrocarbon aromatization performance of the HZSM-5 catalyst was investigated. Physicochemical properties of the catalysts, such as the specific surface area, pore volume and acidity, etc., were characterized to correlate with their aromatization performance data. The results showed that the pore structure of Al2O3 could significantly affect the catalyst performance. As the accessible pore diameter of the catalyst increased from 8.0 nm to 9.0 nm, the light aromatics yield increased by 2.7 percentage points, while the operating time of the catalyst nearly doubled. In addition, catalysts prepared with SiO2 and aluminum phosphate was more active and stable than that prepared with Al2O3, of which the light aromatics yield enhanced 6---8 percentage points and the rtm length, or seivice eife run length nearly doubled.
基金National Natural Science Foundation of China(Grant No.22078278)Hunan Innovative Talent Project(Grant No.2022RC1111)Key Project of Hunan Provincial Education Department(Grant No.22A0131).
文摘Currently,the conversion of waste plastics into high-value products via catalytic pyrolysis enables the advancement of plastics’open-loop recycling.However,enhancing selectivity remains a critical challenge.This study introduces a novel approach to catalytic pyrolysis,utilizing a combination of MCM-41 and modified gallium-based HZSM-5 catalysts,to achieve exceptional selectivity for aromatic liquid-phase products from linear low-density polyethylene.Firstly,to enhance the probability of dehydroaromatization optimization,the type and proportion of metal active sites within the HZSM-5 catalyst are fine-tuned,which would establish equilibrium with acid sites,resulting in a remarkable 15.72%increase in the selectivity of aromatic hydrocarbons.Secondly,to enhance the accessibility of volatiles to active sites,mesoporous MCM-41 with cracking capabilities is introduced.The doping ratio of MCM-41 is meticulously controlled to facilitate the diffusion of cracked volatiles to the active centers of modified gallium-based HZSM-5,enabling efficient reforming reactions.Experimental findings demonstrate that MCM-41 significantly enhances the dehydroaromatization activity of the modified gallium-based HZSM-5 catalyst.Under the influence of MCM-41:Zr_(2)Ga_(3)/HZSM-5=1:2 catalyst,the selectivity for aromatic hydrocarbons reaches an impressive 93.11%,with a notable 60.01%selectivity for benzene,toluene,ethylbenzene,and xylene.Lastly,this study proposes a plausible pathway for the generation of high-value aromatic hydrocarbons using the combined catalyst.
