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Direct synthesis of dimethyl carbonate over rare earth oxide supported catalyst

JIANG Qi, CHENG Jiye, GAO Zhiqin

《化学科学与工程前沿（英文）》 2007年第1卷第3期页码 300-303 doi: 10.1007/s11705-007-0055-z

摘要： Solid base catalysts for the direct synthesis of dimethyl carbonate (DMC) from carbon dioxide, methanol, and propylene oxide were prepared by loading KCl and KCO on the surface of LaO, YO, CeO and NdO. The catalysts were characterized by thermogravimetric analysis (TGA) and X-ray diffraction (XRD) techniques. The catalytic activities were efficiently influenced by the preparation conditions. The optimal loading amount of KCO is 17.6% (mass) for KCl-KCO/YO and 22.2% for other catalysts. Supports affected the activity of catalyst. KCl-KCO/NdO exhibited the highest activity. The activity of KCl-KCO/YO increased with the increase of calcination temperature in the range of 800ºC–900ºC. The formation of KYO, YOCl or YO species probably promoted the catalysts.

关键词： thermogravimetric analysis increase KCl-KCO/NdO catalytic KCl-KCO/YO

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Corrosion behavior of Fe–Cr–Ni based alloys exposed to molten MgCl₂–KCl–NaCl salt with over-added

《化学科学与工程前沿（英文）》 2023年第17卷第10期页码 1608-1619 doi: 10.1007/s11705-023-2349-1

摘要： MgCl₂–NaCl–KCl salts mixture shows great potential as a high-temperature (> 700 °C) thermal energy storage material in next-generation concentrated solar power plants. Adding Mg into molten MgCl₂–NaCl–KCl salt as a corrosion inhibitor is one of the most effective and cost-effective methods to mitigate the molten salt corrosion of commercial Fe–Cr–Ni alloys. However, it is found in this work that both stainless steel 310 and Incoloy 800H samples were severely corroded after 500 h immersion test at 700 °C when the alloy samples directly contacted with the over-added Mg in the liquid form. The corrosion attack is different from the classical impurity-driven corrosion in molten chloride salts found in previous work. Microscopic analysis indicates that Ni preferentially leaches out of alloy matrix due to the tendency to form MgNi₂/Mg₂Ni compounds. The Ni-depletion leads to the formation of a porous corrosion layer on both alloys, with the thickness around 204 µm (stainless steel 310) and 1300 µm (Incoloy 800H), respectively. These results suggest that direct contact of liquid Mg with Ni-containing alloys should be avoided during using Mg as a corrosion inhibitor for MgCl₂–NaCl–KCl or other chlorides for high temperature heat storage and transfer.

关键词： concentrated solar power (CSP) Mg corrosion inhibitor Mg–Ni intermetallic salt purification thermal energy storage (TES)

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Modeling of specific structure crystallization coupling with dissolution

Yuanhui JI, Hongliang QIAN, Chang LIU, Xiaohua LU, Xin FENG, Xiaoyan JI,

《化学科学与工程前沿（英文）》 2010年第4卷第1期页码 52-56 doi: 10.1007/s11705-009-0301-7

摘要： In this paper, the research framework for specific structure crystallization modeling has been proposed in which four steps are required in order to investigate the rigorous crystallization modeling by thermodynamics. The first is the activity coefficient model of the solution, the second is Solid-Liquid equilibrium, the third and fourth are the dissolution and crystallization kinetics modeling, respectively. Our investigations show that the mechanisms of complex structure formation and microphase transition can be analyzed by combining the dissolution and crystallization kinetics modeling. Moreover, the formation mechanism of the porous KCl has been analyzed, which may provide a reference for the porous structure formation in the advanced material synthesis.

关键词： structure crystallization activity coefficient reference KCl dissolution