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Remarkably reducing carbon loss and H2 consumption on Ni–Ga intermetallic compounds in deoxygenation of methyl esters to hydrocarbons

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Journal of Energy Chemistry 2020年第2期29卷 194-208页

作者： Ning Zhao Ying Zheng Jixiang Chen Tianjin Key Laboratory of Applied Catalysis Science and Technology Department of Catalysis Science and EngineeringSchool of Chemical Engineering and TechnologyTianjin UniversityTianjin 300350China

Ni–Ga alloy(Ni/Ga atomic ratio of 8),Ni3Ga and Ni5Ga3 intermetallic compounds(IMCs)catalysts were prepared from Ni–Mg-Al-Ga layered double hydroxides(LDHs)for the deoxygenation of methyl esters to hydrocarbons.In the alloy and IMCs,the presence of Ga reduced the surface Ni atom density,and the charge transfer from Ga to Ni increased the electron density of Ni.In the deoxygenation of methyl laurate,the Ni catalyst gave a complete hydrogenolysis of methyl laurate to CH4at 330°C and 3.0 MPa,while the presence of Ga promoted the HDO pathway and suppressed C–C bond hydrogenolysis and methanation.The Ni5Ga3 catalyst exhibited the best desired performance.Even at 400°C,it gave the yield of C11 and C12 hydrocarbons of ~99%,and the selectivity to CH4(SCH4) was only 2.4%.In the deoxygenation of methyl octanoate and methyl palmitate,the Ni5Ga3 catalyst also gave the yield of hydrocarbons above95%.Reactivity evaluation and methyl propionate-TPD and TPSR results indicate that the C–OCH3 bond instead of the O–CH3 one was cleaved on both Ni and bimetallic Ni–Ga catalysts.It is highlighted that methanol,derived from the C–OCH3 bond hydrogenolysis,mainly decomposed to CO and H2 on IMCs,while it was converted to methane on metallic Ni and alloy.It is of great significance that H2 could be yielded from the methyl ester itself.In short,the utilization of Ni–Ga IMCs can effectively reduce carbon loss and H2 consumption,all of which are ascribed to the geometric and electronic effects of Ga.

关键词： Ni–Ga intermetallic compounds Methyl ester Decarbonylation/decarboxylation Hydrodeoxygenation C–C bond hydrogenolysis Methanation

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Selective hydrogenation of acetylene on SiO_2-supported Ni-Ga alloy and intermetallic compound

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Journal of Energy Chemistry 2019年第2期28卷 40-49页

作者： Lei Wang Fengxu Li Yanjun chen Jixiang Chen Tianjin Key Laboratory of Applied Catalysis Science and Technology Department of Catalysis Science and EngineeringSchool of Chemical Engineering and TechnologyTianjin University

Ni/Si O_2 and bimetallic Ni_xGa/SiO_2 catalysts with different Ni/Ga atomic ratios(x = 10～2) were investigated for the selective hydrogenation of acetylene.It was found that Ni_xGa/SiO_2 showed higher selectivity to ethylene than Ni/Si O_2.This is attributed to the formation Ni-Ga alloy and Ni3 Ga intermetallic compound(IMC) where there was a charge transfer from Ga to Ni,which is favorable for reducing the adsorption strength and amount of ethylene on Ni atoms.As a result,the over-hydrogenation,the C–C bond hydrogenolysis and the polymerization were suppressed,and subsequently the selectivity to ethylene was enhanced.With the decrease of Ni/Ga atomic ratio,the activity and stability of the Ni_xGa/SiO_2 catalysts increased first and then decreased,while the ethylene selectivity tended to increase.Ni_5 Ga/SiO_2 exhibited the best performance.Under the conditions of 180 °C,0.1 MPa,and a reactant(1.0 vol% acetylene,5.0 vol% H_2 and 94 vol% N_2) with the space velocity of 36,000 m L h^(-1) g^(-1),the acetylene conversion maintained at 100% on Ni_5 Ga/SiO_2 during 120 h time on stream and the selectivity to ethylene was 75%～81%after reaction for 68 h.It was also found that the formation of Ni-Ga alloy and Ni_3 Ga IMC suppressed the incorporation of carbon to form NiCx,subsequently enhancing the catalyst stability.Additionally,with increasing the Ga content,the catalyst acid amount and strength tended to increase,which promoted the polymerization and carbon deposition and so the catalyst deactivation.

关键词： Selective hydrogenation Acetylene Ni-Ga alloy Ni3Ga intermetallic compound

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Carbon-coated Ni-Co alloy catalysts:preparation and performance for in-situ aqueous phase hydrodeoxygenation of methyl palmitate to hydrocarbons using methanol as the hydrogen donor

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Frontiers of Chemical Science and Engineering 2022年第4期16卷 443-460页

作者： Yinteng Shi Lin Ai Haonan Shi Xiaoyu Gu Yujun Han Jixiang Chen Tianjin Key Laboratory of Applied Catalysis Science and Technology Department of Catalysis Science and EngineeringSchool of Chemical Engineering and TechnologyTianjin UniversityTianjin 300350China

Carbon-coated Ni,Co and Ni-Co alloy catalysts were prepared by the carbonization of the metal doped resorcinol-formaldehyde resins synthesized by the one-pot extended Stöber method.It was found that the introduction of Co remarkably reduced the carbon microsphere size.The metallic Ni,Co,and Ni-Co alloy particles(mainly 10-12 nm)were uniformly distributed in carbon microspheres.A charge transfer from Ni to Co appeared in the Ni-Co alloy.Compared with those of metallic Ni and Co,the d-band center of the Ni-Co alloy shifted away from and toward the Fermi level,respectively.In the in-situ aqueous phase hydrodeoxygenation of methyl palmitate with methanol as the hydrogen donor at 330℃,the decarbonylation/decarboxylation pathway dominated on all catalysts.The Ni-Co@C catalysts gave higher activity than the Ni@C and Co@C catalysts,and the yields of n-pentadecane and n-C6-n-C16 reached 71.6%and 92.6%,respectively.The excellent performance of Ni-Co@C is attributed to the electronic interactions between Ni and Co and the small carbon microspheres.Due to the confinement effect of carbon,the metal particles showed high resistance to sintering under harsh hydrothermal conditions.Catalyst deactivation is due to the carbonaceous deposition,and the regeneration with CO_(2) recovered the catalyst reactivity.

关键词： Stöber method carbon-coated Ni-Co alloy in-situ hydrodeoxygenation methyl palmitate decarbonylation decarboxylation

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Numerical investigation of Weber number and gravity effects on fluid flow and heat transfer of successive droplets impacting liquid film

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Science China(Technological Sciences) 2023年第2期66卷 548-559页

作者： WANG jixiang QIAN Jian chen Xia LI EnHui chen YongPing College of Electrical Energy and Power EngineeringYangzhou UniversityYangzhou 225009China Department of Mechanical and Aerospace Engineering The Hong Kong University of Science and TechnologyHong Kong 999077China Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application School of Environmental Science and EngineeringSuzhou University of Science and TechnologySuzhou 215009China Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education School of Energy and EnvironmentSoutheast UniversityNanjing 210096China Beijing Institute of Electronic Engineering Beijing 100854China

Droplet-based high heat flux dissipation technique under multi-gravitational environments has gained increasing research attention due to the increased requirements of heat dissipation in advanced air-/space-borne electronics.In this paper,a threedimensional model was developed to investigate the impact of continuous droplets on liquid film under various Weber numbers and gravity loads.In other words,the effects of Weber number and gravity load on the flow and heat transfer characteristics were investigated.The results demonstrated that the dissipated heat flux was positively correlated with both Weber number and gravity load.A large Weber number indicated larger kinetic energy of a droplet,leading to a greater disturbance on the impacted film area.When the Weber number was doubled,the average wall heat flux could be enhanced by 36.3%.In addition,the heat flux could be boosted by 5.4%when the gravity load ranged from 0 to 1g.Moreover,a weightless condition suppressed the vapor escape rates on the heating wall where the volume fraction of the vapor on the wall could increase by 20%under 0g,leading to deteriorated heat transfer performance.The novelty in this paper lies in the accurate three-dimensional modeling of an aerospaceoriented droplet impacting two-phase heat transfer and fluid dynamics,associating macro-scale thermal performance to microscale thermophysics mechanisms.The findings of this study could guide the development of aerospace-borne spray cooling facilities for advanced aerospace thermal management.

关键词： multiple droplets impact phase-change heat transfer multiphase fluid dynamics weightlessness hyper-gravity

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Psychosomatic symptoms affect radiotherapy setup errors in early breast cancer patients

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Chinese Journal of Cancer Research 2021年第3期33卷 323-330页

作者： Yi He Chang Gao Ying Pang Jixiang Chen Lili Tang Key Laboratory of Carcinogenesis and Translational Research(Ministry of Educatdon/Beijing) Department of Psycho-oncologyPeking University Cancer Hospital&InstituteBeijing 100142China National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital Department of OutpatientChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing 100021China Key Laboratory of Carcinogenesis and Translational Research(Ministry of Education/Beijing) Department of Radiation OncologyPeking University Cancer Hospital&InstituteBeijing 100142China

Objective: To examine the trajectory of psychosomatic symptoms and to explore the impact of psychosomatic symptoms on setup error in patients undergoing breast cancer radiotherapy.Methods: A total of 102 patients with early breast cancer who received initial radiotherapy were consecutively recruited. The M.D. Anderson Symptom Inventory(MDASI) and three different anxiety scales, i.e., the Self-Rating Anxiety Scale(SAS), State-Trait Anxiety Inventory(STAI), and Anxiety Sensitivity Index(ASI), were used in this study. The radiotherapy setup errors were measured in millimetres by comparing the real-time isocratic verification film during radiotherapy with the digitally reconstructed radiograph(DRR). Patients completed the assessment at three time points: before the initial radiotherapy(T1), before the middle radiotherapy(T2), and before the last radiotherapy(T3).Results: The SAS and STAI-State scores of breast cancer patients at T1 were significantly higher than those at T2 and T3(F=24.44, P<0.001;F=30.25, P<0.001). The core symptoms of MDASI were positively correlated with anxiety severity. The setup errors of patients with high SAS scores were greater than those of patients with low anxiety levels at T1(Z=-2.01, P=0.044). We also found that higher SAS scores were associated with a higher risk of radiotherapy setup errors at T1(B=0.458, P<0.05).Conclusions: This study seeks to identify treatment-related psychosomatic symptoms and mitigate their impact on patients and treatment. Patients with early breast cancer experienced the highest level of anxiety before the initial radiotherapy, and then, anxiety levels declined. Patients with high somatic symptoms of anxiety may have a higher risk of radiotherapy setup errors.

关键词： Psychosomatic symptom anxiety setup error radiotherapy breast cancer

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Efficient hydrothermal deoxygenation of methyl palmitate to diesel-like hydrocarbons on carbon encapsulated Ni–Sn intermetallic compounds with methanol as hydrogen donor

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Frontiers of Chemical Science and Engineering 2023年第2期17卷 139-155页

作者： Haonan Shi Xiaoyu Gu Yinteng Shi Dandan Wang Sihao Shu Zhongze Wang Jixiang Chen Tianjin Key Laboratory of Applied Catalysis Science and Technology Department of Catalysis Science and EngineeringSchool of Chemical Engineering and TechnologyTianjin UniversityTianjin 300350China

Porous carbon-encapsulated Ni and Ni-Sn intermetallic compound catalysts were prepared by the one-pot extended Stöber method followed by carbonization and tested for in-situ hydrothermal deoxygenation of methyl palmitate with methanol as the hydrogen donor.During the catalyst preparation,Sn doping reduces the size of carbon spheres,and the formation of Ni-Sn intermetallic compounds restrain the graphitization,contributing to larger pore volume and pore diameter.Consequently,a more facile mass transfer occurs in carbon-encapsulated Ni-Sn intermetallic compound catalysts than in carbonencapsulated Ni catalysts.During the in-situ hydrothermal deoxygenation,the synergism between Ni and Sn favors palmitic acid hydrogenation to a highly reactive hexadecanal that easily either decarbonylate to n-pentadecane or is hydrogenated to hexadecanol.At high reaction temperature,hexadecanol undergoes dehydrogenation-decarbonylation,generating n-pentadecane.Also,the C-C bond hydrolysis and methanation are suppressed on Ni-Sn intermetallic compounds,favorable for increasing the carbon yield and reducing the H_(2) consumption.The npentadecane and n-hexadecane yields reached 88.1%and 92.8%on carbon-encapsulated Ni_(3) Sn_(2) intermetallic compound at 330℃.After washing and H_(2) reduction,the carbon-encapsulated Ni_(3) Sn_(2) intermetallic compound remains stable during three recycling cycles.This is ascribed to the carbon confinement that effectively suppresses the sintering and loss of metal particles under harsh hydrothermal conditions.

关键词： extended Stöber method carbon encapsulated Ni-Sn intermetallic compounds confinement in-situ hydrothermal deoxygenation hydrogenation decarbonylation

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Flexible ureteroscopic treatment of kidney stones: How do the new laser systems change our concepts?

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Asian Journal of Urology 2024年第2期11卷 156-168页

作者： Simin Yu Linhu Liu Ya Li Liang Zhou Jixiang Chen Hong Li Kunjie Wang Department of Urology Institute of Urology(Laboratory of Reconstructive Urology)West China HospitalSichuan UniversityChengduSichuanChina

Objective: Flexible ureteroscopy (fURS) has become a widely accepted and effective technique for treating kidney stones. With the development of new laser systems, the fURS approach has evolved significantly. This literature review aims to examine the current state of knowledge on fURS treatment of kidney stones, with a particular focus on the impact of the latest laser technologies on clinical outcomes and patient safety.Methods: We conducted a search of the PubMed/PMC, Web of Science Core Collection, Scopus, Embase (Ovid), and Cochrane Databases for all randomized controlled trial articles on laser lithotripsy in September 2023 without time restriction.Results: We found a total of 22 relevant pieces of literature. Holmium laser has been used for intracavitary laser lithotripsy for nearly 30 years and has become the golden standard for the treatment of urinary stones. However, the existing holmium laser cannot completely powder the stone, and the retropulsion of the stone after the laser emission and the thermal damage to the tissue have caused many problems for clinicians. The introduction of thulium fiber laser and Moses technology brings highly efficient dusting lithotripsy effect through laser innovation, limiting pulse energy and broadening pulse frequency.Conclusion: While the holmium:yttrium-aluminum-garnet laser remains the primary choice for endoscopic laser lithotripsy, recent technological advancements hint at a potential new gold standard. Parameter range, retropulsion effect, laser fiber adaptability, and overall system performance demand comprehensive attention. The ablation efficacy of high-pulse-frequency devices relies on precise targeting, which may pose practical challenges.

关键词： Laser lithotripsy Urolithiasis Thulium laser Holmium:yttrium-aluminum-garnet Moses effect

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Thioetherification of isoprene and butanethiol on transition metal phosphides

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Journal of Energy Chemistry 2018年第3期27卷 930-939页

作者： Tianyu Ren Mingfeng Li Yang Chu Jixiang Chen Tianjin Key Laboratory of Applied Catalysis Science and Technology Department of Catalysis Science and Engineering School of Chemical Engineering and Technology Tianjin University Research Institute of Petroleum Processing SINOPEC

Thioetherification between mercaptan and diolefin is an efficient process to remove mercaptans in FCC gasoline at mild condition, during which the selective hydrogenation of diolefin to monoolefin is also expected. Here, Si O2 supported transition metal（Fe, Co, Ni, Mo and W） phosphides were tested for the thioetherification of isoprene and butanethiol on a fixed-bed reactor at 120℃ and 1.5 MPa H2, and their structure before and after reaction was characterized by means of XRD, HRTEM, N2 sorption, CO chemisorption, NH3-TPD, XPS and TG. It was found that, among different metal phosphides, Mo P/Si O2 showed the best performance, and the optimal nominal Mo P loading was 25%. Apart from the nature of metal, the density of metal and acid sites determined the catalyst performance. Metal site was mainly responsible for hydrogenation of isoprene, while acid site dominantly contributed to the thioetherification and the polymerization of olefins. Moreover, a balance between metallic and acidic functions is required to arrive at a desired performance. Excessive metal sites or acid sites led to the over-hydrogenation of isoprene or the severe polymerization of olefins, respectively. 25%Mo P/Si O2 was tested for 37 h time on stream, and butanethiol conversion maintained at 100%; although isoprene conversion remarkably decreased, the selectivity to isopentenes exceeded 80% after reaction for 11 h. We suggest that the deactivation of Mo P/Si O2 is mainly ascribed to the butanethiol poisoning and the carbonaceous deposit, especially the former.

关键词： Transition metal phosphides Bifunctional catalyst Thioetherification Selective hydrogenation Catalyst deactivation

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Effect of a second metal(Co,Fe, Mo and W) on performance of Ni_2P/SiO_2 for hydrodeoxygenation of methyl laurate

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Journal of Energy Chemistry 2016年第3期25卷 418-426页

作者： Zhengyi Pan Rijie Wang Ziyang Nie Jixiang Chen Tianjin Key Laboratory of Applied Catalysis Science and Technology Department of Catalysis Science and Engineering School of Chemical Engineering and Technology Tianjin University

NiP/SiOand bimetallic Ni MP/Si O2(M = Co, Fe, Mo, W; Ni/M atomic ratio=5) catalysts were prepared by the temperature-programmed reduction method. The catalysts and their precursors were characterized by means of UV–Vis DRS, H-TPR, XRD, TEM, CO chemisorption and NH-TPD. Their performance for the deoxygenation of methyl laurate was tested on a fixed-bed reactor. The results show that the main phase was NiP in all catalysts, and M(M = Co, Fe, Mo, W) entered the lattice of NiP forming solid solution. Different from Fe and Co, the introduction of Mo and W into NiP/SiOreduced the phosphide particle size and increased the acid amount. In the deoxygenation reaction, the turnover frequency of methyl laurate increased on the catalysts in the order of NiMoP/SiO, NiP/SiO, Ni WP/Si O2, NiFeP/SiOand NiCoP/SiO, which is influenced by the size of phosphide particles and the interaction between Ni and M(M = Fe, Co, Mo or W). The introduction of the second metal(especially Mo and W) into NiP/SiOpromoted the hydrodeoxygenation pathway. This is mainly attributed to the interaction between Ni and the second metal. Finally, the Ni MoP/SiOcatalyst was tested at 340 oC, 3 MPa, methyl laurate WHSV of 14 h-1and H/methyl laurate molar ratio of 25 for 132 h, and its deactivation took place. We found that the catalyst deactivation mainly resulted from carbonaceous deposit rather than the sintering of metal phosphide crystallites.

关键词： Bimetallic phosphide Solid solution Methyl laurate Hydrodeoxygenation Decarbonylation

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Control Strategies of Large-scale Residential Air Conditioning Loads Participating in Demand Response Programs

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CSEE Journal of Power and Energy Systems 2022年第3期8卷 880-893页

作者： jixiang Wang Xingying chen Jun Xie Shuyang Xu Kun Yu Lei Gan College of Energy and Electrical Engineering Hohai UniversityNanjing 211100China

Residential air conditioning(RAC)loads have great potential to be included in demand response(DR)programs.This paper studies large-scale RAC loads participating in DR programs,such as modeling,parameters identification,DR characteristics and control strategies.First,an aggregate model of large-scale RAC loads are established based on the buildings’performance with heat storage and insulation,avoiding the calculation of a single RAC model.Then,parameters of the aggregate model are identified based on the RACs’power and outdoor temperatures.Based on the aggregate model,DR characteristics of RAC loads are analyzed,including the dynamic relationship between power,outdoor and indoor temperature,and the potential of DR combined with the users’comfort.Next,the DR control strategies adapted for large-scale RAC loads are established by adjusting the temperature set-points.The DR strategies consider users’comfort and calculate the control signals of each RAC load according to the DR power,including adjustment temperature and adjustment time,which are sent to each RAC load for execution.In the DR process,the control center does not need to obtain the users’indoor temperature,which is conducive to protecting the users’privacy.DR strategies of RAC loads when the control degree within/beyond the DR potential are both proposed,and a load recovery control strategy is also introduced.Finally,the effectiveness and accuracy of the proposed model and DR control strategies are verified by simulation results.

关键词： Control strategies demand response direct load control parameters identification residential air conditioning loads

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