One algorithm and one method for PNNI(Private Network to Network Interface) routing were presented. The algorithm is OIL (Older Is Leader) algorithms for Peer Group selection, and the method is the DOO (Distributed ob...One algorithm and one method for PNNI(Private Network to Network Interface) routing were presented. The algorithm is OIL (Older Is Leader) algorithms for Peer Group selection, and the method is the DOO (Distributed object-oriented) method for HDOS (Hierarchy Distributed-Object System), PNNI systems and IP(Internet Protocol) networks. Based on the specifications from ATM forum, and the creative ideas from Distributed System realization, this paper studies and analyzes the private ATM network environment. The OIL algorithm and the DOO method are both for PNNI routing protocol. Through the PNNI simulation, the availability and robustness are proved for the above two improvements.展开更多
A fuzzy requirement based strategy for QoS service in broadband networks was presented. With the analysis of QoS service in ATM networks and broadband IP networks, it gave a requirement based strategy for QoS service...A fuzzy requirement based strategy for QoS service in broadband networks was presented. With the analysis of QoS service in ATM networks and broadband IP networks, it gave a requirement based strategy for QoS service application with Fuzzy language evaluation principles. The requirement parameters are chosen according to the WANT/COST rule, and a fuzzy set is constructed to realize the fuzzy determinant. The simulation results show that it is useful to evaluate the QoS service in broadband networks, and to effectively simplify the access protocols and solve the billing issues in broadband networks.展开更多
In this study, inhibition of tall oil fatty acid hydrodeoxygenation(HDO) activity due to addition of rosin acid over sulfided Ni Mo/Al_2O_3 was investigated. Oleic acid and abietic acid were used as model compounds fo...In this study, inhibition of tall oil fatty acid hydrodeoxygenation(HDO) activity due to addition of rosin acid over sulfided Ni Mo/Al_2O_3 was investigated. Oleic acid and abietic acid were used as model compounds for fatty acid and rosin acid respectively in tall oil. After completion of each HDO experiment,the Ni Mo catalysts were recovered and used again under the same conditions. The results showed that the oleic acid HDO activity of sulfided catalysts was inhibited by addition of abietic acid due to competitive adsorption and increased coke deposition. The rate of carbon deposition on the catalysts increased when abietic acid was added to oleic acid feed. Moreover, the coke was in a more advanced form with higher stability for the catalysts exposed to both oleic acid and abietic acid. Furthermore, a clear correlation between the rate of coke formation and concentration of abietic acid was observed.展开更多
"H_(2)-free" HDO is a revolutionary route to circumvent the limitations of H_(2)-fed HDO reactors for biomass upgrading.This work demonstrates the viability of this economically appealing route when an adequ..."H_(2)-free" HDO is a revolutionary route to circumvent the limitations of H_(2)-fed HDO reactors for biomass upgrading.This work demonstrates the viability of this economically appealing route when an adequate catalyst is implemented.Herein,we have developed a new family of Pt catalysts supported on N-doped activated carbons for the H_(2)-free HDO process of guaiacol.Several N-donors have been used to tune the catalyst’s structural and electronic properties.As a general trend,the N-promoted samples are more selective towards oxygen-depleted products.The best performing material,namely Pt/PANI-AC reached outstanding guaiacol conversion values-ca.75% at 300℃ while displaying reasonable stability for multiple recycling operations.The advanced performance is ascribed to the modified electronic and acid-base properties which favor guaiacol activation and C-O cleavage,as well as the excellent dispersion of the Pt nano particles.展开更多
The Ni-Nb_(2)O_(5)nanocatalysts have been prepared by the solgel method,and the catalytic hydrodeoxygenation(HDO)performance of anisole as model compound is studied.The results show that Nb exists as amorphous Nb_(2)O...The Ni-Nb_(2)O_(5)nanocatalysts have been prepared by the solgel method,and the catalytic hydrodeoxygenation(HDO)performance of anisole as model compound is studied.The results show that Nb exists as amorphous Nb_(2)O_(5)species,which can promote Ni dispersion.The addition of Nb_(2)O_(5)increases the acidity of the catalyst.However,when the content of niobium is high,there is an inactive Nb-Ni-O mixed phase.The size and morphology of Ni grains in catalysts are different due to the difference of Nb/Ni molar ratio.The Ni_(0.9)Nb_(0.1)sample has the largest surface area of 170.8 m^(2)·g^(-1)among the catalysts prepared in different Nb/Ni molar ratios,which is mainly composed of spherical nanoparticles and crack pores.The HDO of anisole follows the reaction route of the hydrogenation HYD route.The Ni_(0.9)Nb_(0.1)catalyst displayed a higher HDO performance for anisole than Ni catalyst.The selectivity to cyclohexane over the Ni_(0.9)Nb_(0.1)sample is about 10 times that of Ni catalyst at 220℃and 3 MPa H_(2).The selectivity of cyclohexane is increased with the increase of reaction temperature.The anisole is almost completely transformed into cyclohexane at 240℃,3 MPa H_(2)and 4 h.展开更多
Biomass is considered the largest renewable energy source and an important alternative for biofuel production.The fast pyrolysis of biomass is an economical and advantageous to get bio-oil.However,bio-oil has a large ...Biomass is considered the largest renewable energy source and an important alternative for biofuel production.The fast pyrolysis of biomass is an economical and advantageous to get bio-oil.However,bio-oil has a large amount of oxygenated compounds and needs upgrade.The catalytic process of HDO(hydrodeoxygenation)is the most efficient way to remove oxygen from the bio-oil.In this paper,it was studied the HDO phenol(300℃and 35 atm)on catalysts based on cobalt or copper oxides supported on HBeta zeolite.The catalysts were characterized by XRD(X-ray diffraction),FTIR(infrared spectroscopy)and NH3-TPD(desorption of ammonia).The results showed the presence of CO304(cobalt oxide)and CuO(copper oxide).The measurements showed the presence of acid sites weak,moderate and strong and that the impregnation of the metal oxide modifying the acidity of the support.The results showed the following order HDO conversion:CoHBeta〉CuHBeta〉HBeta.The presence of the cobalt or copper catalysts contributes to the increase in conversion due to hydrogenation.All catalysts were selective to benzene,but only the impregnated catalysts showed selectivity to cyclohexane and cyclohexene.展开更多
To extend the practical application of biomass upgrading conversion to liquid fuel,it is crucial to develop highly catalytic and reversible nonprecious metal catalysts.Herein,we propose a high-throughput density funct...To extend the practical application of biomass upgrading conversion to liquid fuel,it is crucial to develop highly catalytic and reversible nonprecious metal catalysts.Herein,we propose a high-throughput density functional theory(DFT)approach to design a high-efficiency catalyst for the selective electrocatalytic upgrading of vanillin via hydrodeoxygenation(HDO).The optimal pyridinic and pyrrolic nitrogen carbon transition metal(TM)-based monolayers exhibit excellent activity for producing2-methoxy-4-methylphenol(MMP)from vanillin.The pyridinic and pyrrolic nitrogen carbon substrates can provide unique sites to support TM atoms,and TM-pyridinic or pyrrolic N moieties serve as catalytic activity sites for the electrocatalytic upgrading of vanillin.Our DFT calculations suggest that the pyridinic N@TM(TM=Zr,Ru,Rh,Os and Ir)and pyrrolic N@TM(TM=Rh and Os)catalysts possess high activity for MMP synthesized from vanillin,and they have a relatively small limiting potential(U_(L))of the rate-determining step.A new route reaction path was used to explore the activity of metal nitrogendoped carbon catalysts,finding that a single metal atom through strong electron correlation between metal and N_(4)C_(8)sites can improve the activity of the vanillin HDO process.Our results show that pyridinic N@Ir and pyrrolic N@Rh with limiting potential(U_(L))of 0.04 and 0.29 V are the most preferable candidate catalysts for the vanillin HDO process.The high stability and relatively low|U_(L)|for vanillin electrocatalytic upgrading are the best candidate electrocatalysts.This work proposes new ideas for designing and developing novel catalysts for selective HDO of biomass under real conditions.展开更多
In-line hydro-treatment of bio-oil vapor from fast pyrolysis of lignocellulosic biomass （hydro-pyrolysis of biomass） is studied as a method of upgrading the liquefied bio-oil for a possible precursor to green fuels....In-line hydro-treatment of bio-oil vapor from fast pyrolysis of lignocellulosic biomass （hydro-pyrolysis of biomass） is studied as a method of upgrading the liquefied bio-oil for a possible precursor to green fuels. The nobel metal （Pt） and non-noble metal catalysts （Mo2C and WC） were compared at 500 ℃ and atmospheric pressure which are same as the reaction conditions for fast pyrolysis of biomass. Results indicated that under the pyrolysis conditions, the major components, such as acids and carbonyls, of the fast pyrolysis bio-oil can be completely and partially hydrogenated to form hydrocarbons, an ideal fossil fuel blend, in the hydro-treated bio-oil. The carbide catalysts perform equally well as the Pt catalyst regarding to the aliphatic and aromatic hydrocarbon formation （ca. 60%）, showing the feasibility of using the cheap non-noble catalysts for hydro-pyrolysis of biomass.展开更多
Bio-oil from biomass pyrolysis cannot directly substitute traditional fuel due to compositional deficiencies.Catalytic hydrodeoxygenation(HDO)is the critical and efficient step to upgrade crude bio-oil to high-quality...Bio-oil from biomass pyrolysis cannot directly substitute traditional fuel due to compositional deficiencies.Catalytic hydrodeoxygenation(HDO)is the critical and efficient step to upgrade crude bio-oil to high-quality bio-jet fuel by lowering the oxygen content and increasing the heating value.However,the hydrocracking reaction tends to reduce the liquid yield and increase the gas yield,causing carbon loss and producing hydrocarbons with a short carbon-chain.To obtain high-yield bio-jet fuel,the elucidation of the conversion process of biomass catalytic HDO is important in providing guidance for metal catalyst design and optimization of reaction conditions.Considering the complexity of crude bio-oil,this review aimed to investigate the catalytic HDO pathways with model compounds that present typical bio-oil components.First,it provided a comprehensive summary of the impact of physical and electronic structures of both noble and non-noble metals that include monometallic and bimetallic supported catalysts on regulating the conversion pathways and resulting product selectivity.The subsequent first principle calculations further corroborated reaction pathways of model compounds in atom-level on different catalyst surfaces with the experiments above and illustrated the favored C-O/C-O scission orders thermodynamically and kinetically.Then,it discussed hydrogenation effects of different H-donors(such as hydrogen and methane)and catalysts deactivation for economical and industrial consideration.Based on the descriptions above and recent researches,it also elaborated on catalytic HDO of biomass and bio-oil with multi-functional catalysts.Finally,it presented the challenges and future prospective of biomass catalytic HDO.展开更多
文摘One algorithm and one method for PNNI(Private Network to Network Interface) routing were presented. The algorithm is OIL (Older Is Leader) algorithms for Peer Group selection, and the method is the DOO (Distributed object-oriented) method for HDOS (Hierarchy Distributed-Object System), PNNI systems and IP(Internet Protocol) networks. Based on the specifications from ATM forum, and the creative ideas from Distributed System realization, this paper studies and analyzes the private ATM network environment. The OIL algorithm and the DOO method are both for PNNI routing protocol. Through the PNNI simulation, the availability and robustness are proved for the above two improvements.
基金National‘86 3’ High Technolgy Plan!(86 3-317-0 1-0 1-0 1-99)
文摘A fuzzy requirement based strategy for QoS service in broadband networks was presented. With the analysis of QoS service in ATM networks and broadband IP networks, it gave a requirement based strategy for QoS service application with Fuzzy language evaluation principles. The requirement parameters are chosen according to the WANT/COST rule, and a fuzzy set is constructed to realize the fuzzy determinant. The simulation results show that it is useful to evaluate the QoS service in broadband networks, and to effectively simplify the access protocols and solve the billing issues in broadband networks.
基金Formas (Contracts: 239-2012-1584 and 239-2014-164) and Preem for the financial support
文摘In this study, inhibition of tall oil fatty acid hydrodeoxygenation(HDO) activity due to addition of rosin acid over sulfided Ni Mo/Al_2O_3 was investigated. Oleic acid and abietic acid were used as model compounds for fatty acid and rosin acid respectively in tall oil. After completion of each HDO experiment,the Ni Mo catalysts were recovered and used again under the same conditions. The results showed that the oleic acid HDO activity of sulfided catalysts was inhibited by addition of abietic acid due to competitive adsorption and increased coke deposition. The rate of carbon deposition on the catalysts increased when abietic acid was added to oleic acid feed. Moreover, the coke was in a more advanced form with higher stability for the catalysts exposed to both oleic acid and abietic acid. Furthermore, a clear correlation between the rate of coke formation and concentration of abietic acid was observed.
基金provided by the Department of Chemical and Process Engineering at the University of Surrey and the EPSRC grant EP/R512904/1the Royal Society Research Grant RSGR1180353financial support from Ministerio de Economía,Industria y Competitividad(Spain)through project MAT2016-80285-P。
文摘"H_(2)-free" HDO is a revolutionary route to circumvent the limitations of H_(2)-fed HDO reactors for biomass upgrading.This work demonstrates the viability of this economically appealing route when an adequate catalyst is implemented.Herein,we have developed a new family of Pt catalysts supported on N-doped activated carbons for the H_(2)-free HDO process of guaiacol.Several N-donors have been used to tune the catalyst’s structural and electronic properties.As a general trend,the N-promoted samples are more selective towards oxygen-depleted products.The best performing material,namely Pt/PANI-AC reached outstanding guaiacol conversion values-ca.75% at 300℃ while displaying reasonable stability for multiple recycling operations.The advanced performance is ascribed to the modified electronic and acid-base properties which favor guaiacol activation and C-O cleavage,as well as the excellent dispersion of the Pt nano particles.
基金Major Science and Technology Project of Yunnan Province(202102AE090042)National Natural Science Foundation of China(21766016)+1 种基金the Science and Technology Talent and Platform Program of Yunnan Provincial Science and Technology Department(202005AF150037)the financial support of Taif University Researchers Supporting Project(TURSP-2020/27),Taif University,Taif,Saudi Arabia。
文摘The Ni-Nb_(2)O_(5)nanocatalysts have been prepared by the solgel method,and the catalytic hydrodeoxygenation(HDO)performance of anisole as model compound is studied.The results show that Nb exists as amorphous Nb_(2)O_(5)species,which can promote Ni dispersion.The addition of Nb_(2)O_(5)increases the acidity of the catalyst.However,when the content of niobium is high,there is an inactive Nb-Ni-O mixed phase.The size and morphology of Ni grains in catalysts are different due to the difference of Nb/Ni molar ratio.The Ni_(0.9)Nb_(0.1)sample has the largest surface area of 170.8 m^(2)·g^(-1)among the catalysts prepared in different Nb/Ni molar ratios,which is mainly composed of spherical nanoparticles and crack pores.The HDO of anisole follows the reaction route of the hydrogenation HYD route.The Ni_(0.9)Nb_(0.1)catalyst displayed a higher HDO performance for anisole than Ni catalyst.The selectivity to cyclohexane over the Ni_(0.9)Nb_(0.1)sample is about 10 times that of Ni catalyst at 220℃and 3 MPa H_(2).The selectivity of cyclohexane is increased with the increase of reaction temperature.The anisole is almost completely transformed into cyclohexane at 240℃,3 MPa H_(2)and 4 h.
文摘Biomass is considered the largest renewable energy source and an important alternative for biofuel production.The fast pyrolysis of biomass is an economical and advantageous to get bio-oil.However,bio-oil has a large amount of oxygenated compounds and needs upgrade.The catalytic process of HDO(hydrodeoxygenation)is the most efficient way to remove oxygen from the bio-oil.In this paper,it was studied the HDO phenol(300℃and 35 atm)on catalysts based on cobalt or copper oxides supported on HBeta zeolite.The catalysts were characterized by XRD(X-ray diffraction),FTIR(infrared spectroscopy)and NH3-TPD(desorption of ammonia).The results showed the presence of CO304(cobalt oxide)and CuO(copper oxide).The measurements showed the presence of acid sites weak,moderate and strong and that the impregnation of the metal oxide modifying the acidity of the support.The results showed the following order HDO conversion:CoHBeta〉CuHBeta〉HBeta.The presence of the cobalt or copper catalysts contributes to the increase in conversion due to hydrogenation.All catalysts were selective to benzene,but only the impregnated catalysts showed selectivity to cyclohexane and cyclohexene.
基金financially supported by the National Key R&D Program of China(No.2022YFA1505700)the National Natural Science Foundation of China(Nos.22205232,51971157 and 21601187)+2 种基金the Natural Science Foundation of Fujian Province(No.2023J01310231)XinJiang Tianshan Talent Program(No.2022SNGGNT104)support by High-performance Computing Platform of Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China。
文摘To extend the practical application of biomass upgrading conversion to liquid fuel,it is crucial to develop highly catalytic and reversible nonprecious metal catalysts.Herein,we propose a high-throughput density functional theory(DFT)approach to design a high-efficiency catalyst for the selective electrocatalytic upgrading of vanillin via hydrodeoxygenation(HDO).The optimal pyridinic and pyrrolic nitrogen carbon transition metal(TM)-based monolayers exhibit excellent activity for producing2-methoxy-4-methylphenol(MMP)from vanillin.The pyridinic and pyrrolic nitrogen carbon substrates can provide unique sites to support TM atoms,and TM-pyridinic or pyrrolic N moieties serve as catalytic activity sites for the electrocatalytic upgrading of vanillin.Our DFT calculations suggest that the pyridinic N@TM(TM=Zr,Ru,Rh,Os and Ir)and pyrrolic N@TM(TM=Rh and Os)catalysts possess high activity for MMP synthesized from vanillin,and they have a relatively small limiting potential(U_(L))of the rate-determining step.A new route reaction path was used to explore the activity of metal nitrogendoped carbon catalysts,finding that a single metal atom through strong electron correlation between metal and N_(4)C_(8)sites can improve the activity of the vanillin HDO process.Our results show that pyridinic N@Ir and pyrrolic N@Rh with limiting potential(U_(L))of 0.04 and 0.29 V are the most preferable candidate catalysts for the vanillin HDO process.The high stability and relatively low|U_(L)|for vanillin electrocatalytic upgrading are the best candidate electrocatalysts.This work proposes new ideas for designing and developing novel catalysts for selective HDO of biomass under real conditions.
文摘In-line hydro-treatment of bio-oil vapor from fast pyrolysis of lignocellulosic biomass （hydro-pyrolysis of biomass） is studied as a method of upgrading the liquefied bio-oil for a possible precursor to green fuels. The nobel metal （Pt） and non-noble metal catalysts （Mo2C and WC） were compared at 500 ℃ and atmospheric pressure which are same as the reaction conditions for fast pyrolysis of biomass. Results indicated that under the pyrolysis conditions, the major components, such as acids and carbonyls, of the fast pyrolysis bio-oil can be completely and partially hydrogenated to form hydrocarbons, an ideal fossil fuel blend, in the hydro-treated bio-oil. The carbide catalysts perform equally well as the Pt catalyst regarding to the aliphatic and aromatic hydrocarbon formation （ca. 60%）, showing the feasibility of using the cheap non-noble catalysts for hydro-pyrolysis of biomass.
基金supported by the National Natural Science Foundation of China(Grant No.52236011).
文摘Bio-oil from biomass pyrolysis cannot directly substitute traditional fuel due to compositional deficiencies.Catalytic hydrodeoxygenation(HDO)is the critical and efficient step to upgrade crude bio-oil to high-quality bio-jet fuel by lowering the oxygen content and increasing the heating value.However,the hydrocracking reaction tends to reduce the liquid yield and increase the gas yield,causing carbon loss and producing hydrocarbons with a short carbon-chain.To obtain high-yield bio-jet fuel,the elucidation of the conversion process of biomass catalytic HDO is important in providing guidance for metal catalyst design and optimization of reaction conditions.Considering the complexity of crude bio-oil,this review aimed to investigate the catalytic HDO pathways with model compounds that present typical bio-oil components.First,it provided a comprehensive summary of the impact of physical and electronic structures of both noble and non-noble metals that include monometallic and bimetallic supported catalysts on regulating the conversion pathways and resulting product selectivity.The subsequent first principle calculations further corroborated reaction pathways of model compounds in atom-level on different catalyst surfaces with the experiments above and illustrated the favored C-O/C-O scission orders thermodynamically and kinetically.Then,it discussed hydrogenation effects of different H-donors(such as hydrogen and methane)and catalysts deactivation for economical and industrial consideration.Based on the descriptions above and recent researches,it also elaborated on catalytic HDO of biomass and bio-oil with multi-functional catalysts.Finally,it presented the challenges and future prospective of biomass catalytic HDO.
