Graphene is a two-dimensional form of crystalline carbon, either a single layer of carbon atoms forming a hexagonal lattice or several coupled layers of this honeycomb structure. Graphene is a parent form of all graphitic structures of carbon. However, the field of graphene science and technology is relatively new. Progress depends not only on the basic science but also on the development of new ways to produce graphene on an industrial scale. The present study is focused primarily upon the thermal transport characteristics of graphene nanoribbons. The thermal transport characteristics of graphene nanoribbons are studied using molecular dynamics simulations and by experimental measurements. A specific heat flux is imposed through the graphene nanoribbon. The graphene nanoribbon is considered as a single layer of carbon atoms with each atom bound to three neighbors in a honeycomb structure. The thermal conductivity is determined from the temperature gradient obtained and the heat flux imposed. The present study aims to provide a fundamental understanding of the thermal transport properties of graphene nanoribbons. Particular emphasis is placed upon the effect of various factors on the thermal conductivity of graphene nanoribbons under different conditions. the results indicate that the mean free path of phonons depends on the nanoribbon structure and dimensions. The thermal conductivity increases with increasing nanoribbon length. Graphene nanoribbons offer tremendous promise for providing enhanced transport performance. Graphene undergoes a metallic-to-semiconducting transition as the nanoribbon width decreases. The properties of graphene nanoribbons are highly dependent on their width and edge structure. The graphene nanoribbons can be derived through the longitudinal splitting of carbon nanotubes.Keywords: Graphene nanoribbons; Graphitic structures; Carbon nanotubes; Carbon nanofibers; Thermal properties; Thermal conductivity

Computational fluid dynamics simulations are carried out to better understand how to manage thermally coupled reactors for conducting simultaneous endothermic and exothermic reactions. Particular emphasis is placed upon the mechanisms involved in the heat transfer processes in thermally coupled reactors for hydrogen production by steam reforming. The effects of catalyst layer thickness on the enthalpy of reaction, methanol conversion, and hydrogen yield are delineated. The oxidation and reforming reaction rates involved in the endothermic and exothermic processes are determined. Contour maps denoting temperature, enthalpy, and species mole fractions are constructed and design recommendations are made. The results indicate that the waste heat can efficiently be recovered in a low-temperature region, although the reactivity of a steam reforming reaction is low in such a region. The steam reforming device is configured as to be heated by part of the combustion heat to cause a steam reforming reaction in the device. The steam reforming reaction is endothermic and is therefore typically carried out in an externally heated steam reforming reactor. The incorporation of a simultaneous exothermic reaction to provide an improved heat source can provide a typical heat flux of roughly an order of magnitude above the convective heat flux. Structured catalysts offer heat transfer benefits and extra activity, which is more effective in the inlet zone of the steam reformer. The metallic support is formed substantially to have the same shape as the reactor wall and is arranged in a direct heat conduction relationship with the reactor wall. Desirably all of the tubes contain the same proportions of structured catalyst and particulate catalyst, which provides the benefits of the higher activity, higher heat transfer, and low pressure drop of the structured catalyst at the inlet end and the benefit of the stronger particulate catalyst at the outlet end. Heat transport is more efficient when catalyzed hardware is used in the steam reforming process.Keywords: Heat transfer; Heat management; Heat fluxes; Heat losses; Heat resistances; Heat exchange

In conventional fuel cells, a predominantly diffusive heat and mass transport is established in the diffusion layer. However, conventional fuel cells cannot ensure a heat and mass transport from the porous diffusion layer to the catalytic reaction layer that is sufficiently uniform for this purpose. The present study aims to provide a methodology for determining the characteristics of heat and mass transport in catalytic reaction layers. Numerical simulations are performed using computational fluid dynamics to better understand the characteristics of heat and mass transport in catalytic reaction layers of thermally integrated reformers. The present study aims to provide a fundamental understanding of the heat and mass transport in catalytic reaction layers of thermally integrated reformers. Particular emphasis is placed upon the dimensionless quantities involved in thermally integrated reformer with different catalytic reaction layer structures. The results indicate that a vapor-liquid equilibrium exists when the escape tendency of the specie from liquid to a vapor phase is exactly balanced with the escape phase at the same temperature and pressure. It may be beneficial to utilize the thermodynamic work potential provided by the transfer of heat to drive the separation process in the desired direction. If a chamber partition operates below its maximum heat transfer flux capability, this flux often can be increased by augmenting adjacent latent energy transfer which transfers through the partition as sensible energy. The external balance establishes the net enthalpy offset and therefore the temperature difference and the net amount of liquid that may be evaporated or condensed. A pure diffusive heat and mass transport would lead to an uneven reaction density or current density in the catalytic reaction layer, on account of a corresponding lack of uniformity in the heat and mass transport in the same catalytic reaction layer. A high pressure-drop in the thermally integrated reformer is to be avoided, since a high-pressure drop is associated with correspondingly high-power losses, which in turn results in a low overall efficiency. The conduit surface may vary along the general direction of flow to provide the zones either intermittently or preferably continuously as with an undulating membrane surface. When tubular membranes are employed, which membranes are preferably circular in cross section, the zones are preferably provided by circumferential furrowing.Keywords: Integrated reformers; Temperature differences; Membrane surfaces; Dimensionless quantities; Heat transport; Mass transport

Microchannel reactor designs suffer from a fundamental limitation resulting from the flow configuration in which a reacting stream flows parallel to a heat transfer surface through which the majority of heat is transferred perpendicular to the direction of fluid flow. The present study aims to provide a unique microchannel fluid processing system for performing chemical reactions with temperature control. The present study relates to a unique method for performing reversible endothermic, exothermic reactions, and competing reactions. The method comprises flowing reactants through a reaction channel in thermal contact with a heat exchange channel, and conducting heat in support of the reaction between the reactants and fluid flowing through the heat exchange channel to substantially raise or lower the temperature of the reactants as they travel through the reaction channel.  Particular emphasis is placed upon how to provide improved conversion and selectivity in chemical reactions, provide chemical reactor systems that are compact, and provide thermally efficient chemical reactor systems. The distribution characteristics of temperature and species in micro-structured heat-exchanger reactors are investigated and the reactor performance is evaluated by performing numerical simulations using computational fluid dynamics. The results indicate that microchannel technology is capable of high heat and mass transfer coefficients between a bulk reaction fluid and the catalytic heat exchange surface. Carbon monoxide output from the fuel processor is controlled over the operating range of the processor. When the reaction in the reaction chamber is a reversible exothermic reaction, heat is generated in the reaction chamber and transferred to the heat exchange fluid. Microchannel reactors offer less resistance to heat and mass transfer thus creating the opportunity for dramatic reductions in process hardware volume. While a steam reforming catalyst in the form of a powder or pellets is appropriate in larger devices, diminished performance may result in the form of a powder or pellets in miniature devices and reactors. The steam reforming catalyst contains a suitable amount of at least one metal oxide and cerium to contribute to high methanol conversion properties. The shift reaction increases hydrogen yield while reducing carbon monoxide. Microchannel reactors offer the advantage of exceptional heat exchange integration and can be utilized for approaching optimum temperature trajectories for exothermic, reversible reactions. Keywords: Distribution characteristics; Chemical kinetics; Temperature trajectories; Fluid streams; Thermal gradients; Reaction selectivity

There are significant problems with current methanol steam reformer approaches as applied to vapor phase heterogeneous catalysis. There remains a need for further development in methanol steam reformer processes and systems. The present study aims to provide an improved reactor system and process for the carrying out of vapor phase heterogeneous reactions. The effect of temperature on the methanol mole fraction and effective factor is investigated for a microchannel methanol steam reformer with different shapes of the cross section of the process microchannel. Particular emphasis is placed upon the heat and mass characteristics involved in vapor phase heterogeneous reaction processes in methanol steam reformers. The results indicate that the steam reforming catalyst is adapted to produce a reformate stream from the feed stream, which is delivered to the reforming region at an elevated temperature and pressure. The fuel stream tends to vary in composition and type depending upon the mechanisms used to produce heat. Methanol is a particularly well-suited carbon-containing feedstock for steam reforming reactions. Methanol steam reforming typically takes place at a lower temperature than when other carbon-containing feedstocks are reformed. A methanol steam reforming catalyst is additionally or alternatively not pyrophoric. A benefit of a low temperature shift catalyst is that the reforming catalyst beds do not need to be shielded or otherwise isolated from contact with air to prevent spontaneous oxidation of the catalyst. Improving heat flux from tubular reactor outer environment to inner environment is a critical step to increase reactor efficiency. Smaller diameter catalytic reactors can offer several advantages of improving heat transfer from external heat source to reaction mixture in the tube, enhancing tube life-time by reducing thermal gradients, reducing metal material use, and being applicable for compact steam reformer systems. Keywords: Heterogeneous catalysis; Vapor phases; Reaction processes; Diffusion coefficients; Heat fluxes; Support structures

The use of nanofluids in a wide variety of applications is promising, but poor suspension stability of nanoparticles in the solution hinders the further development of nanofluids applications. The present study aims to provide a fundamental understanding of the thermal and viscosity properties of inhomogeneous fluids with suspended graphene nanoparticles. A graphite material is exfoliated to form graphene particles, and the effect of nanoparticle volume fraction on the material properties of inhomogeneous fluids with suspended graphene nanoparticles is investigated at different temperatures or under oxidation conditions. Particular emphasis is placed upon the effect of nanoparticle volume fraction on the material properties of inhomogeneous fluids with suspended graphene nanoparticles. The results indicate that the bottom-up approach produces low quantities with high quality and large flakes whereas the top-down approach yields a high concentration of suspended flakes with a low yield of mono-layer graphene. Smaller dispersions result in ease of addition of graphene to other desirable emulsions to enhance the uniform coating matrix for protection attributes graphene can provide to the coating. The pressure drop allows the liquid precursor to flow and homogenizes the pass-through liquid of the liquid precursor that contains thin layers of graphene. The phonon Raman scattering changes are correlated with structural changes and defects associated with the hydroxyl and epoxy groups in the basal plane and a variety of alkyl and oxygen-containing functional groups terminating the edges. Graphene-containing nanofluids provide several advantages over the conventional fluids, including thermal conductivities far above those of traditional solid-liquid suspensions, a nonlinear relationship between thermal conductivity and concentration, strongly temperature-dependent thermal conductivity, and a significant increase in critical heat flux. Stability of the nanoparticle suspension is especially essential for practical industrial applications. Introduction of nanoparticles to the fluid changes density, thermal conductivity viscosity, and specific heat. The functionalization process decreases enhancements in thermal conductivity due to formation of surface oxides. In development of nanofluids for heat transfer a fine balance needs to be obtained between increases in thermal conductivity and viscosity. Keywords: Graphene; Nanoparticles; Thermal properties; Viscosity properties; Fluids; Graphite

The effect of wall material thermal conductivity on butane flame stability is investigated for microscale gas fired burners. The present study aims to provide a fundamental understanding of the butane flame stability of microscale gas fired burners at different wall material thermal conductivities. Particular emphasis is placed upon the stability limits over a range of equivalence ratios and the effect of wall material thermal conductivity on the butane flame stability. The results indicate that the wall material thermal conductivity is vital in determining the butane flame stability of the gas fired burners, as the walls are responsible for the majority of the upstream heat transfer as well as the external heat losses. The most effective way of increasing the lean stability limits of the burner is an increase in primary stream inlet temperature. Completing the combustion process near homogeneous stoichiometric conditions, by intensifying the mixing process, may increase nitrogen oxides emissions. To ensure that the combustion process of the furnace is not adversely affected by the presence of the device, the device should not adversely interfere with the flow of products of combustion away from the combustion zone for each burner. Low wall thermal conductivities result in large axial wall-temperature gradients and high maximum temperatures. High wall thermal conductivity leads to uniform temperature profiles without hotspots. Low wall thermal conductivities cause the flame to shift downstream. Increasing wall thermal conductivity has little effect on flame location unless there are significant external heat losses. Typical ceramics allow maximum external heat loss coefficients. Materials with lower wall thermal conductivities limit the upstream heat transfer. Materials with higher wall thermal conductivities result in enhanced heat transfer to the surroundings. The inlet flow velocity plays a competing role in flame stability. There is only a relatively narrow envelope of flow rates within which combustion can be stabilized. The maximum fluid temperature exceeds the adiabatic flame temperature of butane-air mixture computed for room temperature. Keywords: Burners; Combustion; Emissions; Extinction; Flames; Stability

Catalytic reactors for carrying out endothermic or exothermic reactions are of great importance in the particular examples being reactors for the endothermic steam reforming of methanol and reactors for the exothermic catalytic combustion reaction. The present study aims to provide a fundamental understanding of the exothermic and endothermic reaction characteristics and operation methods of integrated combustion-reforming reactors. Particular emphasis is placed upon the simultaneous implementation of the endothermic steam reforming and the heat-supplying exothermic catalytic combustion such that the thermal stability of the reaction system is increased. The effect of catalyst layer thickness on the reaction characteristics is investigated in order to understand how to design and operate such reactors with high efficiency. The results indicate that unique jet design features can be implemented in order to suppress homogeneous combustion and promote heterogeneous catalytic combustion on the channel wall. Diffusion within these small pores in the catalyst layers is typically Knudsen in nature for gas phase systems, whereby the molecules collide with the walls of the pores more frequently than with other gas phase molecules. The composition in the combustion chamber is reacted to produce sufficient heat to sustain the micro-combustion process without energy input. The combustion and reforming processes can be stably and efficiently operated at lower temperatures, without the need for energy input to sustain or even to start the combustion process. Since a palladium component is alloyed with the zinc, generation of carbon monoxide due to the methanol decomposition reaction is suppressed. Direct heating is of considerable advantage as it largely overcomes the problems encountered with reaction rates being limited by the rate of heat transfer through the tube wall especially near the reformer entrance. The conventional methods are suitable for large scale hydrogen gas production, but they are not adequate for middle to small scale hydrogen gas production. As the channel dimension nears the quench diameter or drops below, the contribution of the unwanted gas phase homogeneous combustion reaction is reduced.Keywords: Catalytic reactors; Reaction characteristics; Heat exchange; Carbon monoxide; Partial oxidation; Thermal stability

Carbon nanotubes are excellent candidates for the development of nano-reinforced polymer composite materials. However, assurance of homogeneous dispersion, interfacial compatibility between the carbon nanotube and the polymer, and exfoliation of the aggregates of carbon nanotubes, are required for the successful integration of carbon nanotubes into nanocomposites. The present study is focused primarily upon the electrical and mechanical properties of catalytically-grown multi-walled carbon nanotube-reinforced epoxy composite materials. Particular emphasis is placed upon the effect of carbon loading on the electrical conductivity and the influence of temperature on the loss factor and modulus for the composite materials. The results indicate that the electrical properties of the composite would not be changed from those of the bulk polymer until the average distance between the carbon nanotubes is reduced such that either electron tunneling through the polymer or physical contacts may be formed. Among the challenges introduced in the fabrication of carbon nanotube-filled polymer composites is the necessity to creatively control and make use of surface interactions between carbon nanotubes and polymeric chains in order to obtain an adequate dispersion throughout the matrix without destroying the integrity of the carbon nanotubes. Frequency domain material properties are therefore limited to applications where strains are small and stress is approximately linear with strain and the strain rate. Frequency domain material properties become irrelevant if the material exhibits nonlinear elastic behavior or is subjected to large strains. Depending on the type of polymers in the matrix, above a certain temperature limit, degradation starts or cross-linking starts. The deformed elastic body possess an amount of potential energy equal to the initial amount of potential energy minus the amount of energy irreversibly dissipated. The modulus and loss factor variables of a damping material are highly dependent upon the temperature of the damping material and the vibration frequency. Because of their viscoelastic nature, the stress and strain in viscoelastic materials are not in phase, and, in fact, exhibit hysteresis. The resonant frequency is related to the modulus of the catalytically-grown multi-walled carbon nanotube-reinforced epoxy composite.Keywords: Composite materials; Electrical properties; Mechanical properties; Carbon nanotubes; Electrical conductivity; Loss modulus

The present study is focused primarily upon the fluid mechanics of microchannel reactors for synthesis gas production. The effect of surface features on the reactor performance is explored for the steam reforming reaction. The conversion rate is used to compare the reactor performance of different configurations. For the purpose of comparison, a baseline case is modeled which is a straight channel of the same dimensions as those for the cases with surface features in terms of channel length, channel width, and gap size. The reactor performance with surface features is quantitatively measured using different enhancement factors. The results indicate that the surface features are preferably at oblique angles, neither parallel nor perpendicular to the direction of net flow past a surface. Flow boiling can achieve very high convective heat transfer coefficients, and that coupled with the isothermal fluid allows the heat transfer wall to remain at quasi-constant temperature along the flow direction. Due to the existence of vapor slugs, severe flow and pressure oscillation may occur in microchannel boiling. Critical heat flux occurs when the temperature difference reaches a point where the heat transfer rate changes from nucleate and bubbly flow to local dry out and gas phase resistance starts to dominate heat transfer. As the momentum is increased at higher Reynolds numbers, the relative vorticity or angular force to spin the fluid also increases and thus the number of contacts or collisions with or near the active surface feature walls is also increased. The performance enhancement of the active surface features relative to a corresponding featureless or flat or smooth wall is typically improved as the residence time is decreased.Fluid mechanics of microchannel reactors for synthesis gas productionJunjie ChenDepartment of Energy and Power Engineering, School of Mechanical and Power Engineering, Henan Polytechnic University, Jiaozuo, Henan, 454000, P.R. ChinaCorresponding author, E-mail address: [email protected] present study is focused primarily upon the fluid mechanics of microchannel reactors for synthesis gas production. The effect of surface features on the reactor performance is explored for the steam reforming reaction. The conversion rate is used to compare the reactor performance of different configurations. For the purpose of comparison, a baseline case is modeled which is a straight channel of the same dimensions as those for the cases with surface features in terms of channel length, channel width, and gap size. The reactor performance with surface features is quantitatively measured using different enhancement factors. The results indicate that the surface features are preferably at oblique angles, neither parallel nor perpendicular to the direction of net flow past a surface. Flow boiling can achieve very high convective heat transfer coefficients, and that coupled with the isothermal fluid allows the heat transfer wall to remain at quasi-constant temperature along the flow direction. Due to the existence of vapor slugs, severe flow and pressure oscillation may occur in microchannel boiling. Critical heat flux occurs when the temperature difference reaches a point where the heat transfer rate changes from nucleate and bubbly flow to local dry out and gas phase resistance starts to dominate heat transfer. As the momentum is increased at higher Reynolds numbers, the relative vorticity or angular force to spin the fluid also increases and thus the number of contacts or collisions with or near the active surface feature walls is also increased. The performance enhancement of the active surface features relative to a corresponding featureless or flat or smooth wall is typically improved as the residence time is decreased.Keywords: Fluid mechanics; Microchannel reactors; Surface features; Synthesis gas; Catalyst deactivation; Energy efficiency1. IntroductionA synthesis gas product is a product comprising primarily carbon monoxide and hydrogen. Reformed hydrocarbons may be further reacted in one or more shift reactors to form additional hydrogen in the process stream and separated in a separation unit, such as a pressure swing adsorption unit, to form a hydrogen product [1, 2]. Synthesis gas is conventionally used to produce synthesis gas products such as synthetic crude, or further upgraded to form intermediate or end products [3, 4]. The synthesis gas may also be used to produce one or more oxygenates, for example, ethers and alcohols. Synthesis gas can be produced from methane-containing feedstocks by any number of primary synthesis gas generation reactors [5, 6]. For example, synthesis gas can be produced in a steam methane reformer, an endothermic reactor where reaction is carried out either in heat exchange reactors, or by other means where substantial heat may be transferred to the reacting fluid, such as in the case of autothermal reforming, where a portion of the feedstock is combusted inside the reactor to provide heat for steam reforming either subsequently or in the same location as the combustion [7, 8]. Synthesis gas can also be produced from methane-containing feedstocks by dry reforming, catalytic or thermal partial oxidation and other processes.Various feedstocks can be used to produce synthesis gas and industry desires to process multiple feedstocks [9, 10]. Industry desires the ability to change from one feedstock to another during operation without shutting down the reactor [11, 12]. For example, a synthesis gas producer may desire to use natural gas for six months, naphtha for three months, and then a mixture of natural gas and naphtha for two months [13, 14]. Industry desires to process different feedstocks at optimal energy efficiency while avoiding carbon formation in the primary synthesis gas reactor [15, 16]. In addition to being able to process multiple feedstocks, industry desires to be able to process a feedstock where the composition, particularly the light hydrocarbon concentration in the feedstock, varies over time [17, 18]. For example, synthesis gas may be produced from a refinery off-gas where the light hydrocarbon concentration varies depending upon the refinery operation [19, 20]. If the feedstock contains higher hydrocarbons than methane, that is, hydrocarbons having two or more carbon atoms are used in the steam reforming process, the risk for catalyst deactivation by carbon deposition in the primary synthesis gas generation reactor is increased [21, 22]. Industry desires to avoid carbon formation in the synthesis gas generation reactor.In order to reduce the risk of carbon deposition in the primary synthesis gas generation reactor, hydrogen and synthesis gas production processes may employ at least one catalytic reactor prior to the primary synthesis gas generation reactor where the catalytic reactor is operated at conditions less prone to hydrocarbon cracking than the primary synthesis gas generation reactor [23, 24]. These reactors positioned before the primary synthesis gas generation reactors are referred to as pre-reformers [25, 26]. Pre-reformers can be operated adiabatically or convectively heated by indirect heat transfer with combustion products gases from the primary synthesis gas generation reactor [27, 28]. The activity of the catalyst in the pre-reformer may degrade with use. Industry desires to compensate for the degradation of the pre-reforming catalyst through operational changes to avoid carbon formation in the primary synthesis gas generation reactor while maintaining optimal energy efficiency of the overall process [29, 30]. In hydrogen and synthesis gas production processes employing pre-reformers and steam methane reformers, the hydrocarbon feedstock may be mixed with hydrogen for a resultant stream having one to five percent hydrogen by volume, and subsequently subjected to a hydrodesulphurization pretreatment to remove Sulphur [31, 32]. The hydrocarbon feedstock may also be treated to remove olefins in a hydrogenation reactor. In case hydrogen is present in the feedstock, additional hydrogen might not be added [33, 34]. For steam reforming of heavy naphtha, hydrogen concentrations as high as about 50 percent by volume of hydrogen are known where the mixture is subsequently pretreated in a hydrodesulphurization unit and a hydrogenation reactor [35, 36]. Even higher hydrogen concentrations are possible depending on the feedstock provided.The feedstock, after pretreating, is combined with superheated steam to form mixed feed having a prescribed steam-to-carbon molar ratio [37, 38]. The steam-to-carbon molar ratio is the ratio of the molar flow rate of steam in the mixed feed to the molar flow rate of hydrocarbon-based carbon in the mixed feed. The steam-to-carbon molar ratio for steam methane reforming of natural gas typically ranges from 2 to 5, but can be as low as 1.5. The steam-to-carbon molar ratio is generally higher for steam methane reforming of feedstock containing a greater number of higher hydrocarbons, for example, propane, butane, propane and butane mixtures, and naphtha. Higher steam flow rates are used to suppress carbon formation and enhance the steam reforming reaction. However, higher steam-to-carbon molar ratios disadvantageously decrease the energy efficiency of the reforming process. Industry desires to improve the energy efficiency of steam-hydrocarbon reforming systems [39, 40]. A significant disadvantage which inhibits the wider use of fuel cells is the lack of a widespread hydrogen infrastructure. Hydrogen has a relatively low volumetric efficiency and is more difficult to store and transport than the hydrocarbon fuels currently used in most power generation systems. One way to overcome this difficulty is the use of reformers to convert the hydrocarbons to a hydrogen-rich gas stream that can be used as a feed for fuel cells [41, 42]. Fuel reforming processes, such as steam reforming, partial oxidation, and autothermal reforming, can be used to convert hydrocarbon fuels into a hydrogen rich gas. In addition to the desired product hydrogen, undesirable byproduct compounds such as carbon dioxide and carbon monoxide are found in the product gas. For many uses, such as fuel for proton exchange membrane or alkaline fuel cells, these contaminants reduce the value of the product gas in part due to the sensitivity of proton exchange membrane fuel cells to carbon monoxide and sulfur [43, 44]. In a conventional steam reforming process, a hydrocarbon feed is vaporized, mixed with steam, and passed over a steam reforming catalyst. The majority of the feed hydrocarbon is converted to a mixture of hydrogen, carbon monoxide, and carbon dioxide. The reforming product gas is typically fed to a water-gas shift bed in which much of the carbon monoxide is reacted with steam to form carbon dioxide and hydrogen [45, 46]. However, water-gas shift beds tend to be large complex units that are typically sensitive to air, further complicating their startup and operation.The present study is focused primarily upon the method and apparatus for steam reforming methanol. Carbon monoxide, carbon dioxide and mixtures thereof, can be removed from the hydrogen-rich reformate by subjecting the hydrogen-rich reformate to one or more of a water gas shift reaction, methanation, and selective oxidation. The present design provides a method of generating electricity comprising the steps of reducing the sulfur content of the sulfur-containing hydrocarbon fuel, catalytically converting the reduced-sulfur hydrocarbon fuel to hydrocarbons, steam reforming the mixture of hydrocarbons at a steam reforming temperature in a catalyst bed to produce a reformate comprising hydrogen and carbon dioxide, fixing at least a portion of the carbon dioxide in the reformate with a carbon dioxide fixing material in the catalyst bed to produce a hydrogen-rich reformate, and feeding the hydrogen-rich reformate to an anode of a fuel cell, wherein the fuel cell consumes a portion of the hydrogen rich reformate and produces electricity, an anode tail gas and a cathode tail gas. The method can further include the step of feeding at least a portion of the tail gases to a combustor or anode tail gas oxidizer to produce an exhaust gas for use in the steam reforming of sulfur-containing hydrocarbon fuels. Optionally, but preferably, the method further includes the step of reducing the amount of carbon monoxide and carbon dioxide in the hydrogen-rich reformate by subjecting the hydrogen-rich reformate to one or more of a water gas shift reaction, methanation and selective oxidation. An integrated system in which tail gas from the fuel cell and hydrogen storage system is used to provide heat needed to reform the feed fuel and regenerate the calcium oxide bed. This study aims to feed the hydrogen-rich reformate to an anode of a fuel cell, wherein the fuel cell consumes a portion of the hydrogen-rich reformate and produces electricity, an anode tail gas, and a cathode tail gas. Particular emphasis is placed upon a fuel cell configured to receive the hydrogen-rich reformate from the fuel processor and wherein the fuel cell consumes a portion of the hydrogen-rich reformate and produces electricity, an anode tail gas, and a cathode tail gas.2. MethodsThe microchannel reactor is illustrated schematically in Figure 1 for the steam reforming process. A catalytic reaction channel is a channel containing a catalyst, where the catalyst may be heterogeneous or homogeneous. A homogeneous catalyst may be co-flowing with the reactants. Microchannel apparatus is similarly characterized, except that a catalyst-containing reaction channel is not required. The sides of a microchannel are defined by reaction channel walls. These walls are preferably made of a hard material such as a ceramic, an iron-based alloy such as steel, or a Ni-based, Co-based, or Fe-based superalloy [47, 48]. They also may be made from plastic, glass, or other metal such as copper, aluminum and the like. The choice of material for the walls of the reaction channel may depend on the reaction for which the reactor is intended. In some cases, reaction chamber walls are comprised of a stainless steel or Inconel® which is durable and has good thermal conductivity [49, 50]. The alloys should be low in sulfur, and in some cases are subjected to a desulfurization treatment prior to formation of an aluminide. Typically, reaction channel walls are formed of the material that provides the primary structural support for the microchannel apparatus. Microchannel apparatus can be made by known methods, and in some cases are made by laminating interleaved plates, and preferably where shims designed for reaction channels are interleaved with shims designed for heat exchange. Some microchannel apparatus includes at least 10 layers laminated in a device, where each of these layers contain at least 10 channels; the device may contain other layers with less channels.