A review of recent developments in hydrogen production via biogas dry reforming

Chemical looping technology enables achievement of the simultaneous feedstock conversion and product separation without additional processes via circulating solid intermediates (so-called oxygen/ni...

Chemical Looping Conversion of Gaseous and Liquid Fuels for Chemical Production: A Review

Chemical‐Looping Conversion of Methane: A Review

Yttrium modified Ni-based double-layered hydroxides were tested as novel catalysts in dry methane reforming. The catalysts were characterized by XRF, BET analysis, XRD, TPR-H2, TPD-CO2, TGA/DSC-MS, H2 chemisorption and TEM. Co-precipitation with yttrium (III) nitrate hexahydrate resulted in increased specific surface area, smaller Ni crystallite size, enhanced reducibility, and higher distribution of weak and medium basic sites as compared to Y-free material. The DRM catalytic tests, carried out in the temperature range of 850–600 °C, led to a significant improvement of activity, with the 1.5 wt % Y-promoted catalyst being the most efficient in converting both CH4 and CO2. Moreover, the 10 h test at 700 °C further confirmed enhanced stability for this HTNi-Y1.5 catalyst. Higher CO2 conversion than CH4 conversion and less CO compared to H2 proves that side reactions are occurring simultaneously.

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Yttrium promoted Ni-based double-layered hydroxides for dry methane reforming

Methane (CH4) is the major component of currently abundant natural gas and a prominent green-house gas. Steam reforming of methane (SRM) is an important technology for the conversion of CH4 into H2 and syngas. To improve the catalytic activity and coking resistance of SRM catalysts, great efforts (including the addition of promoters, development of advanced supports, and structural modification, etc.) have been made with considerable progress in the past decade. Meanwhile, a series of novel processes have been explored for more efficient and energy-saving SRM. In this scenario, a comprehensive review on the recent advances in SRM is necessary to provide a constructive insight into the development of SRM technology, however, is still lacking. Herein, the improvements in catalyst construction for conventional SRM and the newly developed SRM processes in the past decade are presented and analyzed. First, the critical issues of SRM catalysts are briefly introduced. Then, the recent research advances of the most popular Ni based catalysts and the catalysts based on the other non-noble metals (Co, Cu, Mo etc.) and the efficient but costly noble metals (Au, Pt, Pd, Rh, Ru etc.) are discussed. Furthermore, the development of the representative modified SRM processes, including thermo-photo hybrid SRM, sorbent enhanced SRM, oxidative SRM, chemical looping SRM, plasma and electrical-field enhanced SRM, is demonstrated, and their advantages and limits are compared. Finally, a critical perspective is provided to enlighten future work on this significant area.

Steam reforming of methane: Current states of catalyst design and process upgrading

In this work, the modification of Ni/SBA-16 oxygen carrier (OC) with yttrium promoter is investigated. The yttrium promoted Ni-based oxygen carrier was synthesized via co-impregnation method and applied in chemical looping steam methane reforming (CL-SMR) process, which is used for the production of clean energy carrier. The reaction temperature (500–750 °C), Y loading (2.5–7.4 wt. %), steam/carbon molar ratio (1–5), Ni loading (10–30 wt. %) and life time of OCs over 16 cycles at 650 °C were studied to investigate and optimize the structure of OC and process temperature with maximizing average methane conversion and hydrogen production yield. The synthesized OCs were characterized by multiples techniques. The results of X-ray powder diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX) of reacted OCs showed that the presence of Y particles on the surface of OCs reduces the coke formation. The smaller NiO species were found for the yttrium promoted OC and therefore the distribution of Ni particles was improved. The reduction-oxidation (redox) results revealed that 25Ni-2.5Y/SBA-16 OC has the highest catalytic activity of about 99.83% average CH4 conversion and 85.34% H2 production yield at reduction temperature of 650 °C with the steam to carbon molar ratio of 2.

Hydrogen Production from Cyclic Chemical Looping Steam Methane Reforming over Yttrium Promoted Ni/SBA-16 Oxygen Carrier

Chemical-looping steam methane reforming (CL-SMR) is based on oxidation–reduction cycles through a solid–gas reaction with an oxygen carrier (OC) for producing high purity hydrogen or synthesis gas. In this study, Ce promoted Ni-based OC was synthesized via co-impregnation method and applied in this process. The presence of CeO2 nanoparticles in the framework of nickel oxide doped SBA-16 oxygen carrier could significantly improve the uniformity and distribution of nickel oxide nanoparticles duo to the restrictional influence of the SBA-16 framework and the strong interaction of nickel and cerium. The reaction temperature (500–750 °C), Ce loading percentage (3.9–23.3 wt. %) and Ni loading percentage (10–30 wt. %) were studied in order to investigate and optimize the catalyst structure and process temperature with maximizing the average CH4 conversion and H2 production yield in this process. The synthesized oxygen carriers were characterized by X-ray powder diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) techniques. The redox results revealed that 20Ni-11.6Ce/S16 oxygen carrier had the high catalytic activity of about 100% average CH4 conversion and 86.98% H2 production yield at reduction temperature of 700 °C.

Synthesis and characterization of cerium promoted Ni/SBA-16 oxygen carrier in cyclic chemical looping steam methane reforming

In this study, yttrium-incorporated SBA-16 supported nickel-based oxygen carriers (OCs) were prepared and evaluated for syngas production in chemical looping steam methane reforming (CL-SMR) process. The mesoporous silica-based support was synthesized by pH-adjustment hydrothermal procedure and then it was impregnated with NiO particles. The influence of pH adjustment in the synthesis step, yttrium loading and nickel weight percentage are investigated on the physicochemical analysis and catalytic performances of OCs. The pH value exhibited significant effect on the formation of well-ordered mesostructure and substitution of yttrium ions within the structure of SBA-16. Thus, a zeolite like mesostructure of Si-Y is formed at the optimal pH value of 5.4. The results revealed that smaller dimensions and higher dispersion of nickel impregnated particles were formed by incorporation of Y2O3 species into the structure of SBA-16. The calcined OCs are tested in CL-SMR process in the temperature range of 500–750 °C. In addition, the performance of optimum OCs through 16 redox cycles are also investigated to study the activity, coke resistance and structural changes over the process time. The results demonstrated that 25.5NiO/Y(40)SBA-16(5.4) OC has the best performance in respect to catalytic activity and structural properties.

Synthesis, characterization and application of Ni-based oxygen carrier supported on novel yttrium-incorporated SBA-16 for efficient hydrogen production via chemical looping steam methane reforming

Hydrogen, as a clean energy carrier, could be produced aided by cyclic oxidation-reduction of oxygen carriers (OCs) in contact with carbonaceous fuel in chemical looping steam methane reforming (CL-SMR) process. In this study, the cerium was incorporated into the SBA-16 support structure to synthesize the Ni/Ce-SBA-16 OC. The supports were synthesized using hydrothermal method followed by impregnation of Ni and characterized via low and wide angle X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), coupled with energy dispersive X-ray (EDX) spectroscopy, and transmission electron micrograph (TEM) techniques. In addition, the effect of various Si/Ce molar ratios (20–60) in the support structure, Ni loading (10–30 wt %), reaction temperature (500–750 °C), and life time of optimal oxygen carrier over 16 cycles were investigated. The results of wide angle XRD and SEM revealed that the incorporation of CeO2 in the channels of SBA-16 caused the formation of nickel metallic particles with smaller size and prevents the coke formation. The results showed that OC with 15 wt % Ni and Si/Ce molar ratio of 40 (15Ni/Ce-SBA-16(40)) has the best performance when compared with other OCs in terms of catalytic activity and structural properties. The methane conversion of about 99.7% was achieved at 700 °C using 15Ni/Ce-SBA-16(40) OC. We anticipate that the strategy can be extended to investigate a variety of novel modified mesoporous silica as the supporting material for the Ni based OCs.

Sanaz Daneshmand-Jahromi

Papers

Hydrogen Production from Cyclic Chemical Looping Steam Methane Reforming over Yttrium Promoted Ni/SBA-16 Oxygen Carrier

Synthesis and characterization of cerium promoted Ni/SBA-16 oxygen carrier in cyclic chemical looping steam methane reforming

Synthesis, characterization and application of Ni-based oxygen carrier supported on novel yttrium-incorporated SBA-16 for efficient hydrogen production via chemical looping steam methane reforming

Synthesis and Application of Cerium-Incorporated SBA-16 Supported Ni-Based Oxygen Carrier in Cyclic Chemical Looping Steam Methane Reforming

A review of chemical looping combustion technology: Fundamentals, and development of natural, industrial waste, and synthetic oxygen carriers