Arabian Journal of Geosciences
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2021
·Vol. 14
·期 8
·1-12
·
IF 1.827
Ding Kangle,Liu Yan,Guan Fujia,Yu Zhenzhen,Wu Yi
Sulfate reduction by activated carbon (AC), a model compound for solid bitumen (pyrobitumen) without gas generative potential, was studied experimentally for the first time. The simulation experiments show that hydrogen sulfide (H 2 S) is produced from hydrothermal reduction of calcium sulfate (CaSO 4 ) by AC at elevated temperatures. This result demonstrates that water can also act as a hydrogen source for H 2 S generation in addition to hydrocarbons. The formation mechanism of H 2 S may undergo a three-stage sequential process with calcium sulfide (CaS) as the unstable intermediate. The reactivity of carbon is thermodynamically higher than that of methane at ≥ 150 o C but lower than that of ethane or propane in sedimentary basins. Carbon-initiated sulfate reduction follows a zero–order reaction with an apparent activation energy E a of 172.36 kJ/mol. When extrapolated to the temperature range of typical oil and gas reservoirs (100–200 o C), the order of the rate constant is determined as propane > ethane > solid bitumen > methane in the TSR of CaSO 4 . Although solid bitumen contributes little to hydrocarbon gas generation, H 2 S derived from carbon-initiated sulfate reduction may act as an indispensable catalyst for the consequent alteration of methane by TSR in deep buried gas reservoirs with high dryness coefficient.
研究领域:
地质学
·
化学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2025
·
IF 6.2
Mengen Hu,Lei Liu,Zhen Wang,Xian Dang,Chengwan Yang,Xinyang Li,Ming Li,Xiaoye Hu,Yue Li,Zhulin Huang,Xinghong Zhang
The pure phase and ultrafine WB 2 powders were successfully synthesized using a liquid phase precursor synergized with boro/carbothermal reduction method. Subsequently, dense WB 2 -SiC composites (99.5%) were fabricated through hot pressing sintering. The effects of La 2 O 3 additive on the densification, mechanical properties, and ablation resistance of WB 2 -SiC composites were systematically investigated. The ablation behavior of the composites was evaluated using a plasma flame. The results indicate that the mass ablation rate of WB 2 -SiC-La 2 O 3 is 0.463 mg/s, and the linear ablation rate is 0.311 μm/s when exposed to a 2273 K plasma flame for 60 s. The excellent ablation resistance is attributed to the reaction between La 2 O 3 and SiO 2 at high temperature, which generates La 2 Si 2 O 7 , effectively pinned in the glassy phase to inhibit the volatilization of B 2 O 3 . Furthermore, La 2 O 3 also reacts with B 2 O 3 and SiO 2 to generate a highly viscous B-Si-O-La protective layer, which blocks the ingress of oxygen.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
产品关联
DOI
高影响因子
Applied Water Science
·
2022
·Vol. 12
·期 11
·1-9
·
IF 5.411
Chen Gangling,Zhang Jianying,Geng Miaomiao,Sunarso Jaka,Wong Ngie Hing,Ma Tianlin,Wang Yujie,Chen Guihua
The support for the membrane is the basis for the preparation and application of the zeolite membrane. Moreover, its cost and properties directly determine the performance of the zeolite membrane and its industrial applications. A novel porous silicon carbide (SiC) support for zeolite membrane bonded with needle-like mullite (3Al 2 O 3 ·2SiO 2 ) was prepared using SiC powders as the raw material and kaolin, Al(OH) 3 , and AlF 3 as the needle-like mullite precursor additives via an in situ high-temperature reactions in an air atmosphere. Effects of the support material composition and the sintering temperature on the sintering behavior, pore structure, permeability, and microstructure of the resultant supports were extensively investigated. The needle-like mullite formation consumed silicon oxide (SiO 2 ) and generated a rigid skeleton structure with a good pore structure and bonding phase. Hence, the porous SiC support exhibited high porosity, with relatively large pore size and mechanical strength, which helped improve the support performance. Notably, the porous SiC support sintered at 1480 °C with in situ inter-particle needle-like mullite bonding exhibited excellent filtration and permeability performance. The porous support materials and methods used in this work are suitable for designing and preparing a novel porous SiC support for zeolite membranes.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
NUCLEAR ENGINEERING AND DESIGN
·
2020
·
IF 1.62
Shijiao Zhao,Jingtao Ma,Xuping Lin,Xing Cheng,Xingyu Zhao,Shaochang Hao,Ziqiang Li,Changsheng Deng,Bing Liu
Zirconia (ZrO 2 ) microspheres are of great interest as a surrogate precursor material for preparation of uranium nitride (UN) microspheres in High Temperature Reactor (HTR). However, the crystallite transformation of ZrO 2 microspheres in cooling process causes cracking of the microspheres. In our study, crack-free nanocrystalline ZrO 2 microspheres were obtained. The tetragonal phase was stabilized at room temperature without doping any stabilizing additives. Firstly, gel microspheres were prepared through internal gelation process. Subsequent heat treatment of gel microspheres in nitrogen was conducted. The effect of heat treatment was investigated by using simultaneous thermogravimetric analysis and differential scanning calorimetric analysis (TGA/DSC). By using X-ray diffraction (XRD), optical microscopy, and field-emission scanning electron microscopy (FE-SEM), the phase compositions, morphology and microstructures of the heat treated microspheres were characterized. The ZrO 2 microspheres treated at 800 °C exhibit room-stabilized tetragonal zirconia phase, with uniform size of 650 ± 15 μm, good sphericity of 1.02 ± 0.01, and relatively high crush strength 122.5 ± 13.8 N/sphere. Finally, a preliminary nitridation was conducted. Those room-stabilized tetragonal zirconia microspheres can be used as a good surrogate precursor for subsequent preparation of nitride microspheres.
研究领域:
材料科学
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核能工程
✓ 已验证
DOI
高影响因子
ACS Catalysis
·
2024
·
IF 11.3
Yuanjie Xu,Jikang Yao,Hongqiao Lin,Qian Lv,Bo Liu,Lizhi Wu,Li Tan,Yihu Dai,Xupeng Zong,Yu Tang
Enhancing catalyst durability is a critical concern in the partial oxidation of methane (POM) to syngas since the reaction is operated at high temperatures (>600 °C). Alongside sintering and coke deposition, the deactivation of the supported Ni catalyst is often due to the in situ oxidation of active metallic nanoparticles into inactive cations during the POM reaction. Herein, a Ni/BN catalyst was developed by introducing functional CeOx as a promoter to stabilize the Ni sites. The optimized 4Ni/7.5Ce/BN catalyst, comprising 4 wt % Ni and 7.5 wt % Ce on BN, exhibits enhanced stability during continuous testing at 600 °C for 125 h without any deactivation, which is comparable to that of noble metal catalysts. Comprehensive investigations reveal that maintaining the metallic state of Ni under reaction atmosphere is crucial for the stability of the catalyst. The construction of CeOx on BN effectively inhibits migration and oxidation of the catalytically active Ni0 species.
研究领域:
化学工程
·
催化材料科学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 93
·51184-51193
·
IF 3.708
Qing Zhang,Tao Wu,Peng Zhang,Ruijuan Qi,Rong Huang,Xuefeng Song,Lian Gao
Hydrogen reduction of hierarchical spinel intermediates that were synthesized by a facile hydrothermal method results in Ni/γ-Al2O3 nanocomposites with Ni nanoparticles (∼5.5 nm) well dispersed and embedded in nanoflakes of the hollow Al2O3 microspheres. The good dispersion of small metal nanoparticles and strong metal–support interactions that resulted from decomposition of spinel intermediates during reduction are essential for the efficient and sustainable high temperature dry reforming of methane (DRM) catalysis. The high surface area (170 m2 g−1) composite catalysts show coke and sintering resistance in long term DRM catalysis at 750 °C, the highest temperature ever tested for hierarchical nanostructures. Ni loadings and the calcination temperatures of the spinel intermediate are investigated for their effect on the morphology and the catalytic performance of the final catalysts. It is interesting that some initially non-active control catalysts can be activated during long term testing.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）