Methane reforming reactions

Interestingly, this situation is very different when we consider activation of NH3 or H2O by coadsorbed O. This would typically occur in the Ostwald reaction that oxidizes ammonia to NO or the methane reforming reaction in which CH4 reacts with O2 or H2O to give CO, CO2, and H2. 

Methane reforming reaction is accomplished under the action of heat collected from mirror concentrator of solar light. The mixture of CO and H2 produced in this reaction can be stored and then, when necessary, converted into high-potential heat (with the temperature up to 950 K) in the methanation catalytic reactor. The efficiency of solar-to-chemical energy conversion as high as... 

Because Pd-alloy membranes operate at high temperatures in the range of WGS reaction and on the lower end of methane reforming reaction, they can be used in a membrane reactor configuration for the simultaneous separation of hydrogen. As discussed earlier,... 

Here iii " and mout denote the mass flow rate of the mixture entering from the inlet and leaving from the outlet respectively. Rate of consumption and rate of production of each species A is denoted by m sed and mv d. These rates include the flux of reactants, which take part in electrochemical reactions, across the chan-nel/electrode interfaces and also the consumption and production of species due to methane reforming reaction on the anode side. Both hydrogen and carbon monoxide electrochemistry was considered and it was assumed that n2, the fraction of the current that is produced from H2 oxidation, is known. Thus the specie consump-... 

For the steam reforming reaction (10.20) at the anode, some formulae describing the reaction rate have been proposed [11, 12], To model the steam reforming reaction, it is better to measure the reaction rate for the methane reforming reaction using a practical Ni/YSZ cermet. In the present calculations, the following empirical formula is used as the reaction rate ... 

The reactor can operate with either a liquid-phase reaction or a gas-phase reaction. In both types, temperature is very important. With a gas-phase reaction, the operating pressure is also a critical design variable because the kinetic reaction rates in most gas-phase reactions depend on partial pressures of reactants and products. For example, in ammonia synthesis (N2 + 3H2 O 2NH3), the gas-phase reactor is operated at high pressure because of LeChatelier s principle, namely that reactions with a net decrease in moles should be mn at high pressure. The same principle leads to the conclusion that the steam-methane reforming reaction to form synthesis gas (CH4 + H20 O CO + 3 H2) should be conducted at low pressure. 

The methane reforming reactions have been among the first reactions to be proposed and analyzed for chemical energy transport. The main energy carrying step is the steam/methane reaction... 

These reactions increase the heating value of the gas product, since methane has a high heat of combustion. However, these reactions are very slow except under high pressure and in the presence of a catalyst. Another source of the methane in the syngas is the pyrolysis process. Reaction R-4.11 is the reverse steam methane reforming reaction. All reactions that produce methane are exothermic reactions. 

Fig. 12 Methane reforming reaction at the anode of a molten carbonate fuel cell. The reaction between fuel and water takes place in the outer part of the anode, the produced hydrogen reacts at the interface anode-electrolyte.

In the hydrogen production from fossil fiiels, if it is chemical to chemical conversion such as by tire steam-coal gasification reaction or by tire steam-methane reforming reaction, there is no such thermodynamic limitation by the Carnot efficiency. 

Tokyo Tech also conducted a conceptual design study on a long-life multipurpose small-size fast reactor with a medium-temperature hydrogen production system using the sorption-enhanced steam-methane reforming reaction [9],... 

Light hydrocarbons, mainly methane or products deriving from methane reforming reactions (see Sect. 2.1)... 

Autothermal reforming is a combination of partial oxidation and steam reforming carried out in a single reactor. The endothermic heat of reaction for the steam methane reforming reaction is supplied by partial oxidation of the hydrocarbon feedstock in the first section of the reactor. 

Catalyst deactivation and resistance to coking are two important issues of the methane reforming reaction with CO2 over Ni based catalysts because of their potential industrial application. Chen and Wren (9) and Bhattacharya and Chang (10) have recently proposed that the nickel aluminate spinel produced by interaction between nickel and alumina has a positive effect on the suppression of carbon deposition in CO2 reforming of methane. On the other hand, the formation of various types of nickel silicate species between the nickel and the support, attributed to the strong metal-support interaction, has been reported in Ni-silica catalysts (11,12). From these conclusions, it seems interesting to study the influence of Ni-silica interaction on carbon deposition. 

Regeneration of Ni and Ni-Cr/AliOs Catalysts for Methane Reforming Reactions... 

The flattening of the current-voltage curves at higher current densities (see Fig. 9) is caused by the temperature increase in the stack during operation under load. This is more pronounced in the curve for methane operation, because at lower current densities the cooling due to the methane reforming reaction at the anode still dominates the temperature profile. 

For many applications (e.g. fuel cells) it is essential to remove the CO, any residual methane or water, and CO2 produced by the water-gas shift reaction. The typical steam-methane reformer reaction has an exit stream with 70% to 80% H2. A multiple... 

Zirconia, lanthana, and ceria have been recently reported as promoters of methane reforming reactions. Incorporation of a 5 wt% ZrOg to a base Ni/SiOg catalyst resulted in excellent performance for the reforming of methane with a CO2+ O2 mixture in a fluidised bed reactor. A conversion of CH4 near thermodynamic equilibrium and low Hg/CO ratio (l

catalyst deactivation for 10 h on-stream, in a most energy efficient and safe manner. It has been argued that Zr02 could promote the dispersion of Ni on the silica substrate, which has a direct effect on its reduction behaviour, COg adsorption and catalytic... 

Methane steam reforming is a chemical process to produce hydrogen and synthesis gas mixture by combination of steam and methane in a reformer at appropriate temperature and pressure in presence of suitable metal-based catalysts [4], In recent years hydrogen economy has become an interest of the world, methane reforming reaction will play an important role in future hydrogen economy and new applications of synthesis gas mixture [5],... 

As noted above, heat must here be provided to the feed side to sustain the methane reforming reaction. The first option is a high temperature heat source (e.g., gases from fuel combustion) through a dedicated heat transfer surface (Fig. 10.13a). Various plant layouts are possible, employing different oxidants and fuel examples include oxy-combustion of the membrane retentate, or natural gas and hydrogen combustion with high temperature gas turbine flue gas or with fresh... 

A selective membrane device can be integrated into a reaction environment in two different ways directly inside the reaction environment, or assembled in a series of reaction units according to an open architecture. In the following sections, these two configurations are described and evaluated with a steam methane reforming reaction used as an example to elucidate benefits and drawbacks. 

Mbodji, M., Commenge, J. M., Falk, L., Di Marco, D., Rossigno, F., Prost, L., et al. (2012). Steam methane reforming reaction process intensification by using a milistructured reactor experimental setup and model validation for global kinetic rate estimation. Chemical Engineering Journal, 207, 871—884. 

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