超临界 CO2萃取辣椒籽油的动力学研究简

A mathematical model for extraction of red pepper seed oil with supercritical CO2 was proposed. Some factors influencing the process were investigated, including operation pressure, temperature and extraction yield Xe （%）. The model was solved by the method of weighted residuals and used to simulate the process numerically. The kinetic equation is expressed as Xe =-16.8606exp（-t/9.98177） ＋ 16.95457 and the simulation results are in excellent agreement with the experimental data. The optimal operating parameters are 30 MPa, 318 K and 60 min.     

Effect of sodium content on the interaction between Ni and support and catalytic performance for syngas methanation over Ni/Zr–Yb–O catalysts

In this paper, Ni/Zr–Yb–O catalysts with different sodium contents are prepared by a co-precipitation method, using aqueous Na₂CO₃ solution as a precipitant, and the effect of sodium on the catalyst structure and catalytic performance for syngas methanation is extensively investigated using five Ni/Zr–Yb–O catalysts, containing 0, 0.5, 1.5, 4.5 and 13.5 wt% Na⁺, those are denoted as Cat-1, Cat-2, Cat-3, Cat-4 and Cat-5 respectively. It is found that the interaction between Ni and support determines the catalytic performance of Ni/Zr–Yb–O and the residual sodium content negatively affects the interaction between Ni and support. Cat-1 exhibits an excellent catalytic performance. During a long run time of 380 h, no deactivation is observed and both CO conversion and CH₄ selectivity maintain a level above 90%. However, Cat-3 and Cat-5 suffer rapid deactivation under the same reaction condition. The characterization results indicate the strong interaction between Ni and support enables Cat-1 to possess well dispersed Ni species, resistance to sintering and carbon deposition and thus the excellent catalytic performance. However, the presence of sodium ions over Ni/Zr–Yb–O degrades the interaction between Ni and support and the catalytic performance, especially for the stability. The relative weak interaction between Ni and support results in severe sintering of both ZrO₂ and Ni under the reaction condition, carbon deposition and the poor catalytic performance.     

9%Ni钢及其在LNG储罐建造中的焊接简

9％Ni钢是含镍量为8．5％～10％Fe—Ni系低碳马氏体型超低温钢,在-196℃具有优异的强韧性,广泛应用于大型液化天然气储罐等低温设备的建造。9％Ni钢通过合理的合金设计、先进的冶炼技术和严格的热处理保证其优异的低温韧性。克服了在大型LNG储罐建造过程中主要出现的孤坑裂纹、横焊打底焊道贯穿裂纹和气孔等焊接缺陷。结合大型LNG储罐工程建设实例,对9％Ni钢及其焊接工艺和焊接工艺评定要点进行归纳分析。     

冬季轮胎概况简

介绍冬季轮胎的市场、技术、新产品和试验场测试情况。冬季轮胎市场主要为欧洲、北美、新西兰和日本等,欧洲部分国家强制性规定使用冬季轮胎,2012年日本冬季轮胎销售量同比增长4.3%,达到2304.3万条。冬季轮胎技术以普利司通、米其林、倍耐力和诺基亚技术为代表。2013年世界大型轮胎公司推出多款性能优异的冬季轮胎。试验场测试对冬季轮胎市场和研制具有指导意义。     

Hydrogenation of silicon tetrachloride in microwave plasma简

This study investigated the hydrogenation of silicon tetrachloride （SIC14） in microwave plasma. A new launcher of argon （Ar） and hydrogen （Ha） plasma was introduced to produce a non-thermodynamic equilibrium activation plasma. The plasma state exhibited a characteristic temperature related to the equilibrium constant, which was termed ＂Reactive Temperature＂ in this study. Thus, the hydrogenation of SIC14 in the plasma could easily be handled with high conversion ratio and very high selectivity to trichlorosilane （SiHC13）. The effects of SiC14/Ar and H2/Ar ratios on the conversion were also investigated using a mathematical model developed to determine the op- timum experimental parameters. The highest hydrogenation conversion ratio was produced at a H2/SiCl4 molar ratio of 1, with mixtures of SICl4 and H2 to Ar molar ratio of 1.2 to 1.4. In this plasma, the special system pressure and incident power were required for the highest energy efficiency of hydrogenating SIC14, while the optimum system pressure varies from 26.6 to 40 kPa depending on input power, and the optimum feed gas （He and SiCI4） molar en- ergy input was about 350 kJ. mo1-1.     

Performance of EDAB-HCl acid blended system as fracturing fluids in oil fields简

Due to the high price and formation damage of the guargum fracturing fluid, many oilfields are more and more interested in surfactant based fracturing fluids. The rheological properties of erucicamide dimethyl amidopropyl betaine （EDAB）-HC1 acid blended system and its suitability as fracturing fluid were investigated in this work. The effects of pH, concentration of EDAB, and temperature on the rheological properties of the blended system were studied. The results show that addition of EDAB improved the viscosity of the system from less than 10 mPa. s to about 400 mPa. s, which could retard the acid-rock reaction to about one half at 60℃ and one quarter at 90℃ comparing to straight HC1 acid, suggesting that there is sufficient time for the blended fluid to react with formation rock when it is used as fracturing fluid in an oil field. Core flow tests demonstrated that the EDAB-acid blended fluid could divert itself from high permeability formation core to low permeability one, thus ensuring proper acid placement in the target reservoirs.     

La2O3助剂对甲烷干燥重整催化剂 Ni-γ-Al2O3支撑作用的研究简

The nature of support and type of active metal affect catalytic performance. In this work, the effect of using La203 as promoter and support for Ni/γ-A1203 catalysts in dry reforming of methane was investigated. The reforming reactions were carried out at atmosphenc pressure in the temperature range of 500-2700℃. The activity and stability of the catalyst, carbon formation, and syngas （H2/CO） ratio were determined. Various techniques were applied for characterization of both fresh and used catalysts. Addition of La2O3 to the catalyst matrix improved the dispersion of Ni and adsorption of CO2, thus its activity and stability enhanced.     

Catalytic CO2 Methanation: Providing Optimal Test Conditions for Kinetic Investigations

In the context of using renewable energies and recycling climate-changing gases, methanation of CO₂ provides one possibility. However, volatile availability of renewable energies for hydrogen production and fluctuating CO₂ streams from different sources lead to enhanced demand in investigating the influence of dynamic process operation on the catalyst performance, including detailed kinetic characterization. Reliable kinetic measurements require isothermal temperature control and absence of macrokinetic diffusion limitations. Both were investigated in this work while the determination of steady-state kinetic parameters is part of ongoing studies. Furthermore, a detailed analysis with respect to the long-term-stability of the nickel-based catalyst was performed.     

CO2 Methanation on Nickel Catalysts Supported on Mesoporous High‐Surface‐Area MgSiO3

Nickel catalysts prepared on high‐surface‐area mesoporous MgSiO₃ were synthesized and applied in methanation of CO₂. N₂ adsorption analysis confirmed the presence of the mesoporous structure on the synthesized samples and revealed that the increase in nickel content resulted in a shift of the pore size distributions to smaller pore sizes. Temperature‐programmed reduction analysis illustrated an improvement in reducibility of the catalysts by a higher nickel content. Catalytic results indicated enhanced CO₂ conversion with the increase in nickel percentage up to 15 wt %. The catalysts with higher percentage of nickel provided lower CO₂ conversion and CH₄ selectivity. The %15Ni/MgSiO₃ catalyst exhibited high catalytic stability under optimized conditions.     

Cerium-promoted Ni/SiO2 catalyst for CO methanation

Ce-promoted Ni catalysts were developed and applied in a CO methanation reaction. The 10%Ni/SiO₂ catalyst exhibits poor initial CO conversion (32.8%) and rapid deactivation with the highest methane selectivity during CO the methanation reaction. In contrast, the 4%Ce–10%Ni/SiO₂ catalyst shows dramatically increased initial CO conversion, which is up to 90.7%. Additionally, the apparent activation energy, Ea value, of 4%Ce–10%Ni/SiO₂ was calculated to be 102.2 kJ/mol according to the Arrhenius equation, which is much lower than that of the 10%Ni/SiO₂ catalyst, which was 139.1 kJ/mol. Based on various characterization results, it is found that the added Ce significantly improves the dispersion of the supported nickel, suppresses the sintering of nickel particles, and forms more adsorbed CO species of three-fold carbonyl species, resulting in higher CO conversion and good stability during the CO methanation reaction.     

Effects of penta-coordinated Al3+ sites and Ni defective sites on Ni/Al2O3 for CO methanation

Engineering sophisticated structure of Al₂O₃ and controlling the structure of counterpart metal active sites remain challenges to achieve a high catalytic-performance in heterogeneous catalysis. Herein, we present a confinement strategy to stabilize homogeneous Ni by penta-coordinated Al³⁺ anchoring sites in Al₂O₃. This approach is involved in using a metal–organic framework as host to load Ni²⁺ ions, by the aim of producing a confined Ni/Al₂O₃ catalyst after a standard calcination. Metal–support interaction between Ni and Al₂O₃ was tailored to be medium to avoid the formation of inactive NiAl₂O₄, which favors the generation of more available Ni active sites accessible to the reactants. The resultant Ni/Al₂O₃ exhibited superior catalytic performance in comparison with the control Ni/Al₂O₃ in CO methanation owing to the presence of defective sites on sufficient Ni⁰ surface. Furthermore, the presence of oxygen vacancies on Al₂O₃ and hydrogen spillover contributed toward excellent coke resistance properties in the reaction.     

Co负载量对Co/TiO2催化CO2甲烷化性能影响

采用沉淀-沉积法制备出w(Co)=10%、15%、20%和25%的Co/TiO_2催化剂,并用于催化CO_2甲烷化反应。通过XRD、TEM、N_2吸附-脱附、H_2程序升温还原(H_2-TPR)和CO_2程序升温脱附(CO_2-TPD)对催化剂进行了表征与测试。结果表明,Co的负载影响了催化剂中Co3O4晶粒尺寸、比表面积、孔径以及催化剂的还原性能,且Co物种与TiO_2载体发生了强相互作用。其中,w(Co)=20%的Co/TiO_2催化剂中Co颗粒平均尺寸约为8nm,比表面积及孔径分别为40.9 m2/g和6.96 nm,且Co分散度达10.1%,从而更有利于CO_2甲烷化反应。此外,w(Co)=20%的Co/TiO_2催化剂表面具有最大的中强碱位量(28μmol/g),从而可活化更多的CO_2。活性测试结果表明,当反应温度为400℃、压力0.5 MPa、原料气空速3 600 m L/(g·h)、V(H_2)/V(CO_2)=4时,w(Co)=20%的Co/TiO_2催化剂的活性最好,其CO_2转化率和CH_4选择性可分别达到69.9%和98.3%,且在20 h内保持稳定。     

Novel hierarchical Ni/MgO catalyst for highly efficient CO methanation in a fluidized bed reactor

A facile synthesis of the hierarchical Ni/MgO catalyst is reported, with extremely fine dispersion of Ni nanoparticles (NPs) and high surface oxygen mobility. The hierarchical Ni/MgO catalyst exhibits higher activity for CH₄ formation than that prepared by the impregnation method. The enhanced activity and thermal stability of the hierarchical Ni/MgO catalyst is attributed to hierarchical MgO particles with a multilayer structure and high surface oxygen mobility. This induces better metal‐support interactions, high Ni dispersion to prevent Ni NPs sintering, and the high surface oxygen mobility provides a high resistance to carbon deposition. Compared to the impregnated Ni/MgO catalyst, the hierarchical Ni/MgO catalyst exhibits a better fluidization quality and a higher attrition‐resistance in a fluidized‐bed reactor. This approach to improve the catalytic activity by creation of hierarchical Ni/MgO particles is encouraging for the design of novel catalysts for synthetic natural gas production, especially from the perspective of matching catalysts with fluidized‐bed reactors. © 2017 American Institute of Chemical Engineers AIChE J, 63: 2141–2152, 2017     

A Short Review on Ni-Catalyzed Methanation of CO2: Reaction Mechanism,Catalyst Deactivation,Dynamic Operation

Today, the use of renewable energies and recycling of climate-changing gases are increasingly important. In this context, coupling of methanation with small, decentralized CO₂ sources such as biogas plants provides one possibility. However, fluctuating availability of renewables for hydrogen production in combination with small storage volumes result in an enhanced demand for dynamic process operation. This leads to new research challenges with respect to the required catalysts and the overall process design. To draw reliable conclusions about the catalytic performance under dynamic process operation, the mechanism of the methanation reaction as well as typical deactivation procedures of the catalyst applied under steady-state conditions have to be reviewed thoroughly.     

Modeling of Catalytic CO2 Methanation Using Smart Computational Schemes

An analyzing tool as a sustainable method to combine CO₂ capture and production of CH₄ by utilizing CO₂ as a feedstock is proposed. The impact of incorporating metallic promoters such as Fe, La, Ce, and Co to an Al₂O₃-supported catalyst containing Ni as the first metal in the CO₂ methanation was modeled. Smart models were employed to analyze the CO₂ conversion and CH₄ selectivity in CH₄ production from CO₂. The genetic programming (GP) model provides a mathematical framework for the estimation of CO₂ conversion and CH₄ selectivity. The model inputs are catalyst surface area, temperature, H₂/CO₂ ratio, gas-hourly space velocity, and catalyst pore volume and diameter. The results confirm that the GP model estimates the CO₂ conversion and CH₄ selectivity very well.     

静电纺丝法制备高活性多孔Ni/SiO2甲烷化催化剂

以三嵌段共聚物P123为模板剂,采用静电纺丝法制备了多孔Ni/SiO₂催化剂,考察其在CO甲烷化中的催化性能。采用N₂物理吸脱附测试、扫描电子显微镜（SEM）、X射线衍射（XRD）、H₂-程序升温还原（H₂-TPR）、透射电子显微镜（TEM）、热重分析（TGA）对催化剂的结构性质进行表征。结果表明,静电纺丝法制备的多孔Ni/SiO₂催化剂活性组分Ni在SiO₂载体纤维上高度分散,比表面积大,Ni颗粒尺寸小,金属与载体相互作用强,在CO甲烷化反应中表现出优异的催化活性和稳定性。在温度450℃,压力0.1 MPa,质量空速15000 ml/（g·h）条件下,多孔Ni/SiO₂催化剂CO转化率最高可达96.4%,CH₄选择性可达86.4%。此方法为工业上制备高催化活性且无须二次成型的甲烷化催化剂提供了新思路。