Effect of the synthesis conditions of Ni/Al2O3 catalysts on the biogas decomposition to produce H2-rich gas and carbon nanofibers
Abstract The utilization of biogas as carbon source for the co-production of filamentous-like materials and syngas is proposed. Catalysts with different Ni:Al molar ratios, Al 2 O 3 supports and preparation methods were synthesized. The suitability of the catalysts was analyzed considering activity, stability and carbon yield. Catalysts showed a good performance and similar results according to syngas compositions were obtained. However, some differences related to stability over time and carbon yields were detected. TPR analysis and TEM micrographs of the fresh catalysts revealed the presence of two different Ni particles: large Ni particles with low metal support interaction (MSI) that favoured the formation of encapsulating carbon and small Ni particles inserted in the Al 2 O 3 structure with a greater MSI that lead to nanofilamentous carbons formation. Generally both kinds of Ni particles were observed in all catalysts, however their relative abundance was dramatically affected by the Al 2 O 3 employed, the preparation method and the Ni:Al molar ratio.
Comparative Studies of Non‐noble Metal Modified Mesoporous M‐Ni‐CaO‐ZrO2 (M=Fe, Co, Cu) Catalysts for Simulated Biogas Dry Reforming
The present work is aimed to improve the performance of Ni-based catalysts for biogas dry reforming by adding a second non-noble metal (Fe, Co, Cu) into a previously studied mesoporous Ni-CaO-ZrO2 nanocomposite. Biogas was simulated with equivalent methane and carbon dioxide for the dry reforming reaction. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2 adsorption, temperature-programmed reduction (TPR), thermogravimetric analysis (TGA), and transmission electron microscopy (TEM) measurements were taken to characterize the structural and textual properties of the bimetallic catalysts as well as the accumulated carbon deposition. The addition of Fe leads to a less ordering growth of mesopores of Fe-Ni-CaO-ZrO2 sample, and the existence of Cu results in a relatively larger portion of free NiO in Cu-Ni-CaO-ZrO2. Compared with Fe and Cu, the presence of Co could efficiently form a beneficial dual metal effect and enhance the strong metal support interaction between Ni and CaO-ZrO2, thus enhancing the activity and stability of the catalyst in biogas dry reforming reaction.
Experimental study on ground vibration of blasting the boulder with tandem shaped charging warhead
Hazardous effects of blasting the boulder with the new breaking-blasting equipment-tandem shaped charging warhead are mainly air shock wave, seismic wave and blast slung shot. Blast-induced ground vibration is one of the inevitable effects and may cause substantial damage to nearby structures. Started from the formation process and mechanism of ground vibration to study the seismic wave, the research attained curve of vibration velocity of monitoring points by TC-4850 and carried out differential and fast Fourier transform analysis of the curve. And the results concluded that blasting vibration with tandem shaped charging warhead mainly comes from prime charge; the attenuation law can be predicted by Sadev’s Formula. Explosion vibration frequency range is 20-150 Hz, while with the increase of distance from the blasting center, blasting vibration intensity attenuates rapidly, vibration duration increases and vibration frequency gradually reduces. Compared with general rock blasting, its attenuation rate of blasting vibration is faster with higher frequency and smaller impact on buildings, but the harm effects should not be ignored for the special application environment.