Analysis of Dry Reforming as direct route for gas phase CO2 conversion. The past, the present and future of catalytic DRM technologies

Transition to low carbon societies requires advanced catalysis and reaction engineering to pursue green routes for fuels and chemicals production as well as CO2 conversion. This comprehensive review provides a fresh perspective on the dry reforming of methane reaction (DRM) which constitutes a straightforward approach for effective CO2 conversion to added value syngas. The bottleneck for the implementation of this process at industrial scale is the development of highly active and robust heterogeneous catalysts able to overcome the CO2 activation barrier and deliver sufficient amount of the upgrading products at the desired operation conditions. Also, its high energy demand due to the endothermic nature of the reaction imposes extra difficulties. This review critically discusses the recent progresses on catalysts design ranging from traditional metal-supported catalysts to advanced structured and nanostructured systems with promising performance. The main advantages and culprits of the different catalytic systems are introduced aiming to inspire the catalysis community to further refine these formulations towards the development of “supercatalysts” for DRM. Besides the design of increasingly complex catalyst morphologies as well as other promising alternatives aiming at reducing the energy consumption of the process or tackle deactivation through reactor design are introduced

Catalytic Tri-reforming of Biomass-Derived Syngas to Produce Desired H2:CO Ratios for Fuel Applications

This study focuses on upgrading biomass derived syngas for the synthesis of liquid fuels using Fischer-Tropsch synthesis (FTS). The process includes novel gasification of biomass via a tri-reforming process which involves a synergetic combination of CO2 reforming, steam reforming, and partial oxidation of methane. Typical biomass-derived syngas H2:CO is 1:1 and contains tars that deactivate FT catalyst. This innovation allows for cost-effective one-step production of syngas in the required H2:CO of 2:1 with reduction of tars for use in the FTS. To maximize the performance of the tri-reforming catalyst, an attempt to control oxygen mobility, thermal stability, dispersion of metal, resistance to coke formation, and strength of metal interaction with support is investigated by varying catalyst synthesis parameters. These synthesis variables include Ce and Zr mixed oxide support ratios, amount Mg and Ni loading, and the preparation of the catalyst. Reaction conditions were also varied to determine the influences reaction temperature, gas composition, and GHSV have on the catalyst performance. Testing under controlled reaction conditions and the use of several catalyst characterization techniques (BET, XRD, TPR, XAFS, SEM-EDS, XPS) were employed to better explain the effects of the synthesis parameters. Applications of the resulting data were used to design proof of concept solar powered BTL plant. This paper highlights the performance of the tri-reforming catalyst under various reaction conditions and explains results using catalyst characterization

Quo Vadis Dry Reforming of Methane?—A Review on Its Chemical, Environmental, and Industrial Prospects

In recent years, the catalytic dry reforming of methane (DRM) has increasingly come into academic focus. The interesting aspect of this reaction is seemingly the conversion of CO2 and methane, two greenhouse gases, into a valuable synthesis gas (syngas) mixture with an otherwise unachievable but industrially relevant H2/CO ratio of one. In a possible scenario, the chemical conversion of CO2 and CH4 to syngas could be used in consecutive reactions to produce synthetic fuels, with combustion to harness the stored energy. Although the educts of DRM suggest a superior impact of this reaction to mitigate global warming, its potential as a chemical energy converter and greenhouse gas absorber has still to be elucidated. In this review article, we will provide insights into the industrial maturity of this reaction and critically discuss its applicability as a cornerstone in the energy transition. We derive these insights from assessing the current state of research and knowledge on DRM. We conclude that the entire industrial process of syngas production from two greenhouse gases, including heating with current technologies, releases at least 1.23 moles of CO2 per mol of CO2 converted in the catalytic reaction. Furthermore, we show that synthetic fuels derived from this reaction exhibit a negative carbon dioxide capturing efficiency which is similar to burning methane directly in the air. We also outline potential applications and introduce prospective technologies toward a net-zero CO2 strategy based on DRM

Electrochemical promotion of a dispersed Ni catalyst for H2 production via partial oxidation of methanol

This study reports the electrochemical promotion (EPOC) of Ni particles dispersed in a diamond-like carbon (DLC) matrix. A Ni-DLC (Ni/C molar ratio of 0.1) catalyst film was prepared on a K-βAl2O3 (K+-conductor) solid electrolyte by cathodic arc deposition (CAD). This physical vapour deposition (PVD) technique allows to decrease the metal loading used in the solid electrolyte cell and to electrochemically activate dispersed Ni particles in the methanol partial oxidation (POM) reaction by in-situ controlling the coverage of K+ ions electrochemically transferred to the catalyst surface. As compared with a pure Ni layer prepared by the same technique, the Ni-DLC catalyst film shows a higher specific activity and an improved oxidation resistance under EPOC working reaction conditions. The possibility of electrochemically activate (with a negligible energy consumption) dispersed particles of a non-noble metal catalyst (closely related to commercially catalyst formulations) is of great interest for a further commercialization step of the EPOC phenomena in H2 production reactions and in other catalytic systems.Este estudio informa sobre la promoción electroquímica (EPOC) de partículas de Ni dispersas en una matriz de carbono tipo diamante (DLC). Se preparó una película catalizadora de Ni-DLC (relación molar Ni/C de 0,1) sobre un electrolito sólido de K-βAl2O3 (conductor de K+) mediante deposición por arco catódico (CAD). Esta técnica de deposición física de vapor (PVD) permite disminuir la carga metálica utilizada en la celda de electrolito sólido y activar electroquímicamente las partículas de Ni dispersas en la reacción de oxidación parcial del metanol (POM) mediante el control in situ de la cobertura de iones K+ transferidos electroquímicamente a la superficie del catalizador. En comparación con una capa de Ni pura preparada mediante la misma técnica, la película catalizadora de Ni-DLC muestra una mayor actividad específica y una mejor resistencia a la oxidación en condiciones de reacción de trabajo EPOC. La posibilidad de activar electroquímicamente (con un consumo de energía insignificante) partículas dispersas de un catalizador de metal no noble (estrechamente relacionado con las formulaciones de los catalizadores comerciales) es de gran interés para un posterior paso de comercialización del fenómeno EPOC en reacciones de producción de H2 y en otros sistemas catalíticos

Micro-structured functional catalytic eramic hollow fibre membrane reactor for methane conversion

The most significant issue associated with the oxidative methane conversion processes is the use of pure oxygen, which is extremely expensive. By using a dense oxygen permeable membrane reactor, a possible decrease in the air separation cost can be expected due to the elimination of oxygen plants. Besides, higher reaction yields can be attained due to the selective dosing of oxygen into the reaction zone. This thesis focuses on the development and potential application of functional micro-structured catalytic ceramic hollow fibre membrane reactor (CHFMR) in oxidative methane conversion to syngas (known as partial oxidation of methane (POM)) and to ethane and ethylene (known as oxidative coupling of methane (OCM)). As the membrane reactor performance is crucially dependant on the oxygen permeation rate and good contact between oxygen and methane, two types of membrane reactor designs were proposed in this study. The first design involves the development of CHFMR that consists of two layers i.e.: an outer oxygen separation layer and an inner catalytic substrate layer, known as dual-layer catalytic hollow fibre membrane reactor (DL-CHFMR). The DL-CHFMR was fabricated via a novel single-step co-extrusion and co-sintering technique, in which the thickness and the composition of each functional layer can be controlled in order to improve reactor performance. The second design involves the development of CHFMR with an outer dense separation layer integrated with conical-shaped microchannels open at the inner surface, created via a viscous fingering induced phase inversion technique. Besides substantially reducing resistance across the membrane, the microchannels can also act as a structured substrate where catalyst can be deposited for the catalytic reaction to take place, forming a catalytic hollow fibre membrane microreactor (CHFMMR). Although the CHFMRs discussed in this study are designed particularly for POM and OCM, there are general advantages of such membrane structures and reactor designs for improving the overall reaction performance. Therefore, these reactor designs can be transferred to other important catalytic reactions.Open Acces

電場印加反応場における二酸化炭素を用いた触媒的低温メタン転換

早大学位記番号:新7513早稲田大

Sensitivity analysis and process optimization for biomass processing in an integrated gasifier-solid oxide fuel cell system

Hydrogen (H2) production from biomass is always attractive due to its carbon–neutral nature. However, the high energy requirement in biomass gasification and the processing of synthesis gas (syngas) has become the primary concern of the application of this technique. The combined gasifier-solid oxide fuel cell (SOFC) system shows promising potential for significant energy efficiency improvement. However, there is still space to optimize the performance of such combined systems. A novel zero-dimensional (0D) mass-transfer-based model was developed to find the optimal operating parameters for H2 production and to maximize the power density. Coal, sugarcane bagasse, and marine algae were used as feeds to analyze the effects of relevant parameters. A sensitivity analysis of the operational conditions was undertaken to better understand the characteristic trends associated with the maximum power and H2 production. This work optimized the conditions respected with the power density. It was found that the highest power density could be achieved by manipulating operating variables. It is concluded that marine algae have the highest power output but the lowest system efficiency due to high moisture and ash content. Coal produces low power output than biomasses. Hence, sugarcane bagasse is the most efficient feedstock for integrated gasifier-SOFC systems

Synthesis and characterization of graphene nanosheets supported platinum nanocomposite as catalyst for methanol oxidation

Platinum (Pt) is a noble metal catalyst that is most frequently used as the anode catalyst in direct methanol fuel cell (DMFC) because of its superior catalytic activity performance as compared to other metal catalysts. Besides the merit, Pt catalyst is expensive and also contributes to the problem of Pt poisoning by carbon monoxide (CO) during the methanol oxidation which can reduce the performance of DMFC. The use of carbonaceous material which is graphene nanosheets (GNS) as catalyst support for Pt catalyst can reduce the cost and enhance the catalytic property. Since the GNS have large surface area, the Pt nanoparticles can be dispersed uniformly onto the surface of GNS. Therefore, the main objective of this research is to synthesis and characterize the GNS supported Pt catalyst nanocomposite for methanol oxidation in DMFC. The nanocomposite from GNS and Pt catalyst precursor was fabricated by chemical reduction method using sodium borohydride as reducing agent. The physiochemical properties of the prepared graphene oxide nanosheets, GNS and the catalytic activity performance of GNS/Pt nanocomposite catalyst were successfully studied. Extensive characterization of the produced GNS as catalyst support in terms of morphology, structure, thermal stability and electrical conductivity property were conducted. The results showed that the prepared GNS possess high electrical conductivity of 7.65 S cm-1 thus indicated a highly potential catalyst support. HRTEM and FESEM analysis showed well-dispersed Pt nanoparticles on the surface of GNS with small average particle size around 3.33 nm obtained. The findings were consistent with the XRD data (~4.47 nm) obtained. The catalytic activities of GNS/Pt nanocomposites were measured by cyclic voltammogram. The electrochemical surface area (ECSA) of GNS/Pt nanocomposite catalyst was 0.36 cm2 larger than Vulcan XC-72/Pt (0.25 cm2) and graphite/Pt (0.14 cm2) catalysts. It has been found that GNS/Pt nanocomposite catalyst has better catalytic activity and high stability than Vulcan XC-72/Pt and graphite/Pt catalysts for methanol oxidation reaction. As a conclusion, the GNS/Pt nanocomposite catalyst fabricated in this study possesses appropriate characteristics to be used as anode catalyst in DMFC system