Low Temperature Steam Reforming Of Methane Research Articles

Novel Ni–Ru/CeO2 catalysts for low-temperature steam reforming of methane

Upgrading of biogas and biomethane into H2-rich streams by steam reforming is regarded as an effective strategy to reduce fossil fuel consumption contributing to the transition towards a green energy system. In this context, novel reactor configurations such as membrane reactors appear a promising route for process intensification, but they require novel catalysts more active at low temperatures, stable, and resistant to coke formation. In this work, we prepared and tested structured catalysts characterized by a low Ni content (7 wt%) and a very low Ru content (≤1 wt%) supported on ceria and deposed onto SiC monoliths. Catalysts were tested at low temperatures (<600 °C), i.e. at temperatures suitable for applications in Pd-based membrane reactors. Fresh and used catalysts were characterized by ICP-MS, N2 physisorption, XRD, TEM, SEM-EDS, XPS and H2-TPR to identify the physicochemical properties affecting the catalytic activity. The catalysts showed good activity towards methane reforming, stable performance, and good resistance to coke formation. Ruthenium affects both the intrinsic catalytic activity and the resistance to the inhibiting effect of steam on the reaction rate. This is related to improved redox properties due to the intimacy between the active metals and their strong-metal-support-interaction with the ceria. Finally, our catalysts show self-activation under reaction conditions, which is an interesting property for applications.

Highly Active Catalysts Based on the Rh4(CO)12 Cluster Supported on Ce0.5Zr0.5 and Zr Oxides for Low-Temperature Methane Steam Reforming

Syngas and Hydrogen productions from methane are industrially carried out at high temperatures (900 °C). Nevertheless, low-temperature steam reforming can be an alternative for small-scale plants. In these conditions, the process can also be coupled with systems that increase the overall efficiency such as hydrogen purification with membranes, microreactors or enhanced reforming with CO2 capture. However, at low temperature, in order to get conversion values close to the equilibrium ones, very active catalysts are needed. For this purpose, the Rh4(CO)12 cluster was synthetized and deposited over Ce0.5Zr0.5O2 and ZrO2 supports, prepared by microemulsion, and tested in low-temperature steam methane reforming reactions under different conditions. The catalysts were active at 750 °C at low Rh loadings (0.05%) and outperformed an analogous Rh-impregnated catalyst. At higher Rh concentrations (0.6%), the Rh cluster deposited on Ce0.5Zr0.5 oxide reached conversions close to the equilibrium values and good stability over long reaction time, demonstrating that active phases derived from Rh carbonyl clusters can be used to catalyze steam reforming reactions. Conversely, the same catalyst suffered from a fast deactivation at 500 °C, likely related to the oxidation of the Rh phase due to the oxygen-mobility properties of Ce. Indeed, at 500 °C the Rh-based ZrO2-supported catalyst was able to provide stable results with higher conversions. The effects of different pretreatments were also investigated: at 500 °C, the catalysts subjected to thermal treatment, both under N2 and H2, proved to be more active than those without the H2 treatment. In general, this work highlights the possibility of using Rh carbonyl-cluster-derived supported catalysts in methane reforming reactions and, at low temperature, it showed deactivation phenomena related to the presence of reducible supports.

Integrated Design and Control of Various Hydrogen Production Flowsheet Configurations via Membrane Based Methane Steam Reforming.

This work focuses on the development and implementation of an integrated process design and control framework for a membrane-based hydrogen production system based on low temperature methane steam reforming. Several alternative flowsheet configurations consisted of either integrated membrane reactor modules or successive reactor and membrane separation modules are designed and assessed by considering economic and controller dynamic performance criteria simultaneously. The design problem is expressed as a non-linear dynamic optimization problem incorporating a nonlinear dynamic model for the process system and a linear model predictive controller aiming to maintain the process targets despite the effect of disturbances. The large dimensionality of the disturbance space is effectively addressed by focusing on disturbances along the direction that causes the maximum process variability revealed by the analysis of local sensitivity information for the process system. Design results from a multi-objective optimization study, where only the annualized equipment and operational costs are minimized, are used as reference case in order to evaluate the proposed design framework. Optimization results demonstrate the controller’s ability to track the imposed setpoint changes and alleviate the effects of multiple simultaneous disturbances. Also, significant economic improvements are observed by the implementation of the integrated design and control framework compared to the traditional design methodology, where process and controller design are performed sequentially.

Low temperature steam reforming of methane using metal oxide promoted Ni-Ce0.8Zr0.2O2 catalysts in a compact reformer

Metal oxide (MgO, CaO, and La2O3) promoted Ni-Ce0.8Zr0.2O2 catalysts have been applied for low-temperature steam reforming of methane (SRM), and the promoter effect was investigated. The addition of the metal oxides improved the basicity which enhances the resistance coke formation and catalytic activity. Among the prepared catalysts, the Ni-La2O3-Ce0.8Zr0.2O2 catalyst exhibited high activity and stability at a very high gas hourly space velocity of 621,704 h−1. This was mainly due to high dispersion of Ni, strong basicity of La2O3, and strong interaction between Ni and La2O3.

Investigating the simultaneous process design and control of a membrane reactor for hydrogen production via methane steam reforming

In the present work, the simultaneous process design and control of a membrane reactor for H2 production via methane steam reforming (MSR) is performed. The problem is stated as a non-linear optimization problem with non-linear constraints, which includes economic and controllability criteria in the objective function. A linear model predictive controller (MPC) is implemented to enforce the desired dynamic performance. Utilizing this methodology two pre-defined process flowsheets for H2 production through the low temperature MSR, utilizing palladium-based membranes, are optimally designed based on economic criteria in the form of annualized capital and operating cost, and controllability criteria, in the form of the sum of squared errors during dynamic transitions. The first flowsheet is consisted of an integrated membrane reactor (IMR), whereas the second flowsheet under consideration is consisted of a cascaded arrangement between a reactor and a membrane module in series (CRM). Several other auxiliary processes such as heat exchangers, splitters, and mixers are employed. Rigorous nonlinear dynamic models have been developed assuming one dimensional transport and pseudo-homogenous conditions in the reaction zone in order to emulate the plant dynamics, whereas a linearized version of it is used by the MPC algorithm. Optimization results demonstrate the ability of the integrated process and control design framework to achieve a superior operating performance for a range of several factors affecting the operating conditions of the reactor.

Low Temperature Methane Steam Reforming for SOFC

The properties of flowerlike microspheres ceria based nickel catalyst for low temperature methane steam reforming (SMR) were studied. The ceria microspheres were prepared by hydrothermal method. Catalyst of nano-sized nickel oxide particles based on flowerlike cerium oxide microspheres with high disperse were prepared to achieve simultaneous dehydrogenation of methane and water molecules on multi-active sites. The catalyst was characterized by means of Scanning Electronic Microscope (SEM), X-ray diffraction (XRD). Results showed that this special catalyst NiO/CeO2 had high activity and stability for SMR reaction below 600oC. The stability of the catalyst reached more than 1000 hours. The conversation of methane under 590oC was above 90%. The tests of the influence of different H2O/CH4 mole ratios on activity and selectivity of catalyst showed that 1.5~2.5 ratios was an ideal choice. During the running of micro-tube methane steam reformer with this catalyst, the methane conversion of 556oC kept over 25mol.%.

Ultra-low loading Ru/γ-Al2O3: A highly active and stable catalyst for low temperature solar thermal reforming of methane

Converting solar radiation into chemical energy is an attractive method to increase the energy content of methane by driving endothermic upgrading processes, such as methane steam reforming. Although such solar thermochemical conversions would increase natural gas product yields and reduce greenhouse gas emissions, current costs of solar facilities are prohibitively high. Parabolic troughs, which are a mature and relatively inexpensive form of solar concentrator, are limited to temperatures of ca. 400–600°C. In this regime, commercial methane steam reforming Ni-based catalysts have low activity and rapidly deactivate due to oxidation and coking. Catalysts based on platinum group metals are much more active and stable but their high cost limits their use. Here, we investigate Ru-based catalysts with ultra-low metal loadings for low-temperature methane steam reforming. We show that a Ru/γ-Al2O3 (0.15wt% loading) catalyst outperforms the commercial (12wt% Ni) catalyst by two orders of magnitude in terms of methane conversion normalized by metal loading. Systematic evaluation of catalytic performance over a range of Ru loadings and operating conditions shows a pronounced optimum in catalytic activity versus metal loading. Characterization studies reveal a strong correlation between the catalytic activity and the Ru nanoparticle size distribution. The catalyst features excellent stability at industrially relevant conditions and low steam-to-carbon ratios, making it an attractive option for low-temperature solar reforming of methane.

Experimental Research on Low-Temperature Methane Steam Reforming Technology in a Chemically Recuperated Gas Turbine

Under the operating parameters of a chemically recuperated gas turbine (CRGT), the low-temperature methane steam reforming test bench is designed and built; systematic experimental studies about fuel steam reforming are conducted. Four different reforming forms are employed, including catalyst-only reforming, plasma-only reforming, piecewise synergistic reforming, and parallel synergistic reforming. A better reforming form for CRGT was determined by analyzing the effect of methane space velocity, steam-to-carbon ratio of fuel reforming (S/C), wall temperature, and plasma input power. All of the above factors had an effect on the reforming performance, but a direct and significant effect separately on effective carbon recovery rate, total enthalpy increasing rate, methane conversion, and fuel heating value increasing rate. The effective carbon recovery rate was taken as the chief indicator for choosing the right operating conditions, determining a best methane space velocity of 680 mL/(gcat·h). With the increase of S/C, total enthalpy increasing rate had a significant improvement; wall temperature had a positive effect on reforming, especially in synergistic catalysis. The effect of input power was linked with wall temperature in parallel synergistic reforming, with a greater effect at a higher temperature. Combining the experimental results with the theory analysis, parallel synergistic reforming is best, with a methane conversion of 51.23% and total enthalpy increasing rate of 25.73% at a wall temperature of 500 °C, an input power of 84.53 W, and an S/C value of 2.

Low Temperature Methane Steam Reforming: Catalytic Activity and Coke Deposition Study

Low temperature steam reforming combined with hydrogen-selective membrane offers significant advantages in terms of energy conservation, reduction of GHG emissions and low cost operation. In this study, Ni supported on La/CeO2-ZrO2 is evaluated under steam reforming at temperature <550 C. The catalyst is highly active in steam reforming of methane and water gas shift reaction. Stability test at simulated biogas steam reforming was conducted and the catalyst showed extremely stable performance for long time on stream (90 h) and very low amount of carbonaceous deposits, as determined by TPO and TPH. The above characteristics demonstrate that this catalyst is a potential candidate for use in membrane reactors operating at low temperature for the one-step production of pure hydrogen.

Modelling and Simulation of a Membrane Reactor for the Low Temperature Methane Steam Reforming

Modelling and Simulation of a Membrane Reactor for the Low Temperature Methane Steam Reforming

Ni-Based Catalysts for Low Temperature Methane Steam Reforming: Recent Results on Ni-Au and Comparison with Other Bi-Metallic Systems

Steam reforming of light hydrocarbons provides a promising method for hydrogen production. Ni-based catalysts are so far the best and the most commonly used catalysts for steam reforming because of their acceptably high activity and significantly lower cost in comparison with alternative precious metal-based catalysts. However, nickel catalysts are susceptible to deactivation from the deposition of carbon, even when operating at steam-to-carbon ratios predicted to be thermodynamically outside of the carbon-forming regime. Reactivity and deactivation by carbon formation can be tuned by modifying Ni surfaces with a second metal, such as Au through alloy formation. In the present review, we summarize the very recent progress in the design, synthesis, and characterization of supported bimetallic Ni-based catalysts for steam reforming. The progress in the modification of Ni with noble metals (such as Au and Ag) is discussed in terms of preparation, characterization and pretreatment methods. Moreover, the comparison with the effects of other metals (such as Sn, Cu, Co, Mo, Fe, Gd and B) is addressed. The differences of catalytic activity, thermal stability and carbon species between bimetallic and monometallic Ni-based catalysts are also briefly shown.

Low Temperature Methane Steam Reforming for Hydrogen Production for Fuel Cells

Thus, it is necessary to develop low temperature process to decrease the material cost for the reformer tube. Moreover, if the low temperature process is possible, the lifetime of the re-former tube will be extended considerably. Previously, we have reported that it is possible to operate SRM at 548

Promotion of Methane Steam Reforming Using Ruthenium-Dispersed Microporous Alumina Membrane Reactor

Abstract A membrane reactor with the microporous ruthenium-dispersed alumina membrane is effective in promoting low temperature methane steam reforming. In the temperature range of 300–500 °C, the membrane reactor attained the methane conversion with a twice as large as the equilibrium value by the selective removal of hydrogen from the reaction system.