The development of highly effective metal-zeolite bifunctional catalysts for the hydroisomerization of n-alkanes is a paramount strategy to produce second-generation biofuels with high quality.In this study,polyhexame...The development of highly effective metal-zeolite bifunctional catalysts for the hydroisomerization of n-alkanes is a paramount strategy to produce second-generation biofuels with high quality.In this study,polyhexamethylene biguanide hydrochloride(PHMB)is precisely added to the initial gel to synthesize nanosized ZSM-23 zeolites(Z23-x PH).Due to orientation adsorption and steric hindrance effects of PHMB,each sample of Z23-x PH demonstrates enhanced mesoporosity in comparison with the conventional Z23-C zeolite.Furthermore,the Bronsted acid density of the Z23-x PH samples is also signifi cantly reduced due to a reduction in the distribution of framework Al at T2-T5 sites.The corresponding Pd/23-C and Pd/Z23-x PH bifunctional catalysts with 0.5 wt%Pd loading for n-hexadecane hydroisomerization are prepared by incorporating ZSM-23 zeolites as acid supports.According to the catalytic test results,the suitable addition of PHMB can effectively promote the iso-hexadecane yield.The Pd/Z23-2PH catalyst with an n_(PHMB)/n(_Si)molar ratio of 0.002 demonstrates the highest maximum iso-hexadecane yield of 74.1%at an n-hexadecane conversion of 88.3%.Therefore,the employment of PHMB has provided a simple route for the development of highly effective Pd/ZSM-23 catalysts for n-alkane hydroisomerization.展开更多
The anaerobic digestion(AD)disposal of stover and cattle manure is of great significance to the development of low-carbon economy and green energy in China,but it will also have an impact on the environment,and the de...The anaerobic digestion(AD)disposal of stover and cattle manure is of great significance to the development of low-carbon economy and green energy in China,but it will also have an impact on the environment,and the degree of influence is different for various raw materials.In this study,life cycle assessment(LCA)methods were applied to analyze and compare the impact of corn stovers biogas projects(CSBP)and dairy manure biogas projects(DMBP)on the environment during the whole operation stage.The results of inventory analysis were evaluated by ReCiPe2016 Hierarchy(H)mid-point(problem-oriented)and end-point(destruction-oriented)method,respectively.The results showed that the net energy efficiency of CSBP was higher(763.903 kW·h/FU)and the greenhouse gas(GHG)emission reduction of DMBP was more(5541.418 kg CO_(2)-eq/FU).The anaerobic digestion(AD)units have the greatest environmental impacts,and human carcinogenic toxicity is the largest environmental impact category(1.16-1.43 PE).The key to reducing environmental impact is reducing the input of chemical substances and the waste of electric energy.Both CSBP and DMBP have a favorable impact on ecosystem quality and resources,and CSBP is more beneficial to the environment(-10.297 Pt).Co-digestion is an important measure to reduce the environmental damage from biogas projects.These research results provide theoretical support for the selection of raw materials for large-scale biogas projects in China,provide technical basis for reducing the impact of actual operation on the environment,and promote the resource utilization of agricultural waste and carbon dioxide emission reduction and sequestration.展开更多
基金funded by the National Key Research and Development Project,Intergovernmental International Science and Technology Innovation Cooperation Key Project(No.2018YFE0108800)National Natural Science Foundation of China(No.22278115)Heilongjiang Province Natural Science Foundation(No.YQ2021B010).
文摘The development of highly effective metal-zeolite bifunctional catalysts for the hydroisomerization of n-alkanes is a paramount strategy to produce second-generation biofuels with high quality.In this study,polyhexamethylene biguanide hydrochloride(PHMB)is precisely added to the initial gel to synthesize nanosized ZSM-23 zeolites(Z23-x PH).Due to orientation adsorption and steric hindrance effects of PHMB,each sample of Z23-x PH demonstrates enhanced mesoporosity in comparison with the conventional Z23-C zeolite.Furthermore,the Bronsted acid density of the Z23-x PH samples is also signifi cantly reduced due to a reduction in the distribution of framework Al at T2-T5 sites.The corresponding Pd/23-C and Pd/Z23-x PH bifunctional catalysts with 0.5 wt%Pd loading for n-hexadecane hydroisomerization are prepared by incorporating ZSM-23 zeolites as acid supports.According to the catalytic test results,the suitable addition of PHMB can effectively promote the iso-hexadecane yield.The Pd/Z23-2PH catalyst with an n_(PHMB)/n(_Si)molar ratio of 0.002 demonstrates the highest maximum iso-hexadecane yield of 74.1%at an n-hexadecane conversion of 88.3%.Therefore,the employment of PHMB has provided a simple route for the development of highly effective Pd/ZSM-23 catalysts for n-alkane hydroisomerization.
基金supported by the National Key Research and Development Program of China(Grant No.2023YFE0106000)the National Natural Science Foundation of China(Grant No.52206234).
文摘The anaerobic digestion(AD)disposal of stover and cattle manure is of great significance to the development of low-carbon economy and green energy in China,but it will also have an impact on the environment,and the degree of influence is different for various raw materials.In this study,life cycle assessment(LCA)methods were applied to analyze and compare the impact of corn stovers biogas projects(CSBP)and dairy manure biogas projects(DMBP)on the environment during the whole operation stage.The results of inventory analysis were evaluated by ReCiPe2016 Hierarchy(H)mid-point(problem-oriented)and end-point(destruction-oriented)method,respectively.The results showed that the net energy efficiency of CSBP was higher(763.903 kW·h/FU)and the greenhouse gas(GHG)emission reduction of DMBP was more(5541.418 kg CO_(2)-eq/FU).The anaerobic digestion(AD)units have the greatest environmental impacts,and human carcinogenic toxicity is the largest environmental impact category(1.16-1.43 PE).The key to reducing environmental impact is reducing the input of chemical substances and the waste of electric energy.Both CSBP and DMBP have a favorable impact on ecosystem quality and resources,and CSBP is more beneficial to the environment(-10.297 Pt).Co-digestion is an important measure to reduce the environmental damage from biogas projects.These research results provide theoretical support for the selection of raw materials for large-scale biogas projects in China,provide technical basis for reducing the impact of actual operation on the environment,and promote the resource utilization of agricultural waste and carbon dioxide emission reduction and sequestration.
