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101.
Bin Han Xinwen Ou Zuqi Zhong Shujie Liang Hong Deng Zhang Lin 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(38)
Direct photoconversion of low‐concentration CO2 into a widely tunable syngas (i.e., CO/H2 mixture) provides a feasible outlet for the high value‐added utilization of anthropogenic CO2. However, in the low‐concentration CO2 photoreduction system, it remains a huge challenge to screen appropriate catalysts for efficient CO and H2 production, respectively, and provide a facile parameter to tune the CO/H2 ratio in a wide range. Herein, by engineering the metal sites on the covalent organic frameworks matrix, low‐concentration CO2 can be efficiently photoconverted into tunable syngas, whose CO/H2 ratio (1:19–9:1) is obviously wider than reported systems. Experiments and density functional theory calculations indicate that Fe sites serve as the H2 evolution sites due to the much stronger binding affinity to H2O, while Ni sites act as the CO production sites for the higher affinity to CO2. Notably, the widely tunable syngas can also be produced over other Fe/Ni‐based bimetal catalysts, regardless of their structures and supporting materials, confirming the significant role of the metal sites in regulating the selectivity of CO2 photoreduction and providing a modular design strategy for syngas production. 相似文献
102.
Sean G. Mueller Patrick J. Stallbaumer David A. Slade Susan M. Stagg-Williams 《Catalysis Letters》2005,103(1-2):69-74
Pt–Re supported on Ce0.52 Zr0.48 O2 was studied for the carbon dioxide reforming of methane at 800 °C. Diffuse reflectance fourier transform infrared spectroscopy and temperature programmed reduction studies suggest that Pt and Re segregation occurs during the reaction. The segregation results in an increase in the Pt sites available for CH4 decomposition and results in the bimetallic catalyst exhibiting an increase in the conversion of methane with time on stream. After 20 h of reaction, the CH4 conversion observed for the bimetallic catalyst was the same as the CH4 conversion observed for the monometallic catalyst. 相似文献
103.
由下行床热解和提升管(或输送床)气化组合形成的流化床两段气化将煤气化反应过程解耦为煤热解和半焦气化两个反应阶段,热解产物完全进入气化反应器,利用其中的高温环境和输送的半焦催化作用分别实现焦油的热裂解与催化裂解,完成低焦油气化。利用该流化床两段气化的10 kg/h级实验室工艺实验装置,以榆林烟煤为原料、水蒸气/氧气作为气化剂,变化过量氧气系数ER、蒸汽炭比S/C、热解及气化温度等参数,研究水蒸气/氧流化床两段煤气化制备低焦油合成气的特性。结果表明,流化床两段气化系统可实现稳定运行(实验3 h以上),在ER=0.36和S/C=0.15时,热解和气化的代表温度分别稳定在735℃和877℃,合成气的CO、CO2、H2、CH4、C n H m 和N2含量分别为14.33%、10.07%、18.39%、9.89%、1.82%和45.50%,相应的合成气产量达到1.8 m3/kg,低位热值8.99 MJ/m3,焦油含量0.437 g/m3,展示了制备低焦油合成气的技术特征。对于实际的长时间连续运行,更高的气化温度将使流化床两段气化具有更好的低焦油特性。 相似文献
104.
Novel and Ideal Zirconium-Based Dense Membrane Reactors for Partial Oxidation of Methane to Syngas 总被引:5,自引:0,他引:5
A novel and ideal dense catalytic membrane reactor for the reaction of partial oxidation of methane to syngas (POM) was constructed from the stable mixed conducting perovskite material of BaCo0.4Fe0.4Zr0.2O3– and the catalyst of LiLaNiO/-Al2O3. The POM reaction was performed successfully. Not only was a short induction period of 2 h obtained, but also a high catalytic performance of 96–98% CH4 conversion, 98–99% CO selectivity and an oxygen permeation flux of 5.4–5.8 mlcm–2min–1 (1.9–2.0 molm–2S–1Pa–1) at 850°C were achieved. Moreover, the reaction has been steadily carried out for more than 2200 h, and no interaction between the membrane material and the catalyst took place. 相似文献
105.
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107.
MnOx promotional effects on olefins synthesis directly from syngas over bimetallic Fe‐MnOx/SiO2 catalysts
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Zhengpai Zhang Weiwei Dai Xin‐Chao Xu Jun Zhang Bianfang Shi Jing Xu Weifeng Tu Yi‐Fan Han 《American Institute of Chemical Engineers》2017,63(10):4451-4464
The direct synthesis of lower olefins via the Fischer‐Tropsch reaction (FTO) has been performed over a series of Fe‐MnOx/SiO2 catalysts. The addition of MnOx could improve the dispersion of iron species, and promote the reduction of iron oxide during the activation and subsequent carburization. Moreover, the results of characterization demonstrated that MnOx could enhance the surface basicity of the catalysts due to electronic effects and promote the formation of iron carbides. For the first time, the intrinsic power‐law kinetics for FTO was obtained for both Fe20/SiO2 and Fe20‐Mn1/SiO2 catalysts. Kinetic parameters and structure characterizations indicated that MnOx could facilitate the CO dissociation on the catalyst surface, thus enhancing the adsorption strength and capacity of surface carbonaceous intermediates. The weak hydrogenation of carbonaceous species would boost the selectivities toward lower olefins. Finally, a plausible mechanism for FTO, involving the promotional effects of MnOx on Fe, has been proposed. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4451–4464, 2017 相似文献
108.
Thermodynamic analysis and optimization of RWGS processes for solar syngas production from CO2
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Marcus Wenzel Liisa Rihko‐Struckmann Kai Sundmacher 《American Institute of Chemical Engineers》2017,63(1):15-22
Process systems were investigated for syngas production from CO2 and renewable energy (solar) by the reverse water‐gas shift (RWGS) and the reverse water‐gas shift chemical looping (RWGS‐CL) process. Thermodynamic analysis and optimization was performed to maximize the solar‐to‐syngas (StS) efficiency ηStS. Special emphasis was laid on product gas separation. For RWGS‐CL, maximum StS efficiencies of 14.2 and 14.4% were achieved without and with heat integration, respectively. The StS efficiency is dictated by the low overall efficiency of H2 production. RWGS‐CL is most beneficial for the production of pure CO, where the StS efficiency is one percent point higher compared to that of the RWGS process with heat integration. Heat integration leads to significant reductions in external heat demand since most of the gas phase process heat can be integrated. The StS efficiencies for RWGS and RWGS‐CL achieve the same level as the reported values for solar thermochemical syngas production. © 2016 American Institute of Chemical Engineers AIChE J, 63: 15–22, 2017 相似文献
109.
介绍壳牌煤气化工艺流程中的合成气反吹系统的反吹介质可由洗涤后的粗合成气改为高温高压氮气。改造后 ,出气化装置的合成气组分既可满足下游装置的工艺要求 ,又可节省大量的工程投资 相似文献
110.