Intrinsic rate equations were derived for the steam reforming of methane, accompanied by water. Methane steam reforming kinetics over niysz anodematerials for solid oxide fuelcells. Reactions i and iii are endothermic, but the water gas shift reaction is exothermic. Methane steam reforming kinetics over niysz anodematerials. Kinetics study and modelling of steam methane reforming process over a nioal 2o 3 catalyst in an adiabatic packed bed reactor s. The observed reaction rate was measured on catalyst extrudates to determine diffusion effects within the porous structure of the. Methane steam reforming kinetics over niysz anodematerials for solid oxide fuelcells mogensen, david publication date. Particularly for enginefuel production, air may be present as a reaction component.
Introduction steam methane reforming smr is a major hydrogen production process with more than 70 years of history. The true kinetics of methane steam reforming was measured in powder of nial 2 o 3 catalyst octolyst 1001 from degussa at different temperatures 733890 k for several operating conditions. The first units commissioned in the 1930s were run on light hydrocarbon feedstock at atmospheric pressure l, it took until 1962 for a 15atm steam reformer to come onstream in the united kingdom using liquid hydrocarbon feedstock 24. A comparison of 11 kinetics based on both industrial steammethane reforming catalysts and niysz for sofcs showed that they were. Intrinsic kinetics intrinsic rate equations were derived for the steam reforming of methane, accompanied by watergas shift on a ni mga1204 catalyst. The simulation and optimal project of the commercial process requires information on the intrinsic kinetics. Intrinsic rate equations were derived for the steam reforming of methane, accompanied by watergas shift on a ni mga1204 catalyst. Steam methane reforming process first, water must be heated in a furnace to produce steam. Steam methane reforming is a catalytic process that involves a reaction between natural gas or other light hydrocarbons and steam. Global kinetics of methane total oxidation, dry reforming and partial oxidation appl. Experiments were carried out varying the steam to methane ratio in the feed gas from 1 to 10 and.
Methane steam reforming over an niysz solid oxide fuel. Kinetics, catalysis and mechanism of methane steam. For more than 40 years the catalyzed hydroearbonsteam reforming reaction has been of commercial value. A considerable effort has been put into investigations of the kinetics of methane steam reforming. In smr, methane reacts with steam under 325 bar pressure 1 bar 14. Comparison of catalyst geometries for methane steam reforming.
Kinetic rate data for steam methane reforming smr coupled with water gas shift wgs over an 18 wt. Steam reforming of methane in metalfoam filled reactor. Title rate equation of steammethane reforming reaction on ni. Kinetics, catalysis and mechanism of methane steam reforming. The reaction takes place in a single chamber where the methane is partially oxidized. The reaction pathways and kinetics of steam methane reforming smr over ni111 are investigated using plane wave density functional theory. Steam reforming, partial oxidation and autothermal reforming are the primary methods used for the production of h 2 by using hydrocarbons source. Measurements of effective diffusivities of the gases present in methane steam reforming have been carried out by using the steadystate technique over wide ranges of temperature and pressure in a modified wickekallenbach wk type. Steam methane reforming is the most common and economical way to make hydrogen. Thus, the first reforming step catalytically reacts methane the chief chemical constituent of natural gas to form hydrogen and carbon monoxide in an endothermic heat. Experiments have been carried out to study the kinetics of the methane steam reforming, accompanied by the reverse water gas shift reaction over a commercial. Therefore, in the present work a previously developed kinetic model for methane steam reforming over nialumina catalysts 46 has been. Surface reaction kinetics for oxidation and reforming of h2. Under such circumstance, rh seems to be more advantageous than.
Steammethane reforming kinetics detailed chemistry reduced chemistry userdefined kinetic rates output quantities methane conversion hydrogen yield process fluid temperature tube wall temperature tube side physics 3 ch4 mass fraction h2 mass fraction process temperature. Methane steam reforming kinetics for a rhodiumbased. Surface reaction kinetics of steam and co 2reforming as w ell as oxidation of methane over nickelbased catalysts karla herrera delgado 1, lubow maier 2, steffen tischer 2, alexander zellner. Autothermal reforming atr uses oxygen and carbon dioxide or steam in a reaction with methane to form syngas. Surface reaction kinetics of steam and co2reforming as. The experiments were performed in a plug flow reactor under the conditions of diffusion limitations and away from the equilibrium conditions. Kinetics study and modelling of steam methane reforming process. The reactor employed for the study was made of 7 mm i. Kinetics of steam reforming over a nialumina catalyst. A simulation study of the steam reforming of methaneina. The reaction kinetics depend upon the partial pressure of the steam. The reaction scheme studied is as follows 15, 19, 21, 3235. Al 2 o 3 catalyst, to find out the reaction kinetics of the steam methane reforming process while keeping in mind the condition of diffusion limitations and far from the equilibrium conditions.
New reaction rate constants were determined for this catalyst. In contrast to the steam reforming reactions, the fuel cell reactions are exothermic, because of heat production within the cell caused by the internal resistances. Abstractmethane steam reforming is the key reaction to produce synthesis gas and hydrogen at the industrial scale. Xu and froments model includes both the positive and negative effect of the partial pressure of steam on the reaction kinetics, as it covered both the ranges of partial pressure of steam presented in the previous research. Steam reforming of hydrocarbons on noble metal catalysts. Experiments were carried out varying the steam to methane ratio in the feed gas from 1 to 10. Steam reforming of methane over a commercially available, nickelalumina catalyst was experimentally studied.
Methane steam reforming, methanation and watergas shift. Surface reaction kinetics of steam and co 2 reforming as w ell as oxidation of methane over nickelbased catalysts karla herrera delgado 1, lubow maier 2, steffen tischer 2, alexander zellner. Kinetics providing detailed information of elementary reaction steps for this system, namely microkinetics, has. To investigate the further kinetics, lin et al 6 regarded the smr as. The reactions for the two simultaneous smr mechanisms are shown as equations 1 and 2. Methane steam reforming over an niysz solid oxide fuel cell. Pdf the steammethane reforming reaction on a niysz yttriastabilized zirconia cermet was experimentally investigated in the temperature range of.
Hydrogen production by steam reforming chemical engineering. The simulation and optimal design of the commercial process requires information on the intrinsic kinetics. Mahmud school of chemical and process engineering, the university of leeds, ls2 9jt, uk. The amount of catalyst charge in the reactor was around 0. Fbcr was used for detailed modelling of the catalyst beds considering rigorous intraparticle mass and heat transport. Kinetics study and modelling of steam methane reforming. The thermochemical data are used to develop a microkinetic model of smr that allows for the investigation of reforming pathways and the most abundant reaction intermediates on the catalyst surface at industrially relevant temperatures and pressures. Title rate equation of steammethane reforming reaction on niysz.
Methane steam reforming involves two reversible reactions. Methane steam reforming is the key reaction to produce synthesis gas and hydrogen at the industrial scale. These reactions are also involved in other processes proposed for the production of hydrogen, such as solar driven methane 12 or carbonaceous material steam reforming,14 or autothermal reforming using partial oxidation of hydrocarbons 1518. Comparison of catalyst geometries for methane steam. Kjersti omdahl christensen steam reforming of methane on. Important intermediates such as adsorbed hco and cooh species are included in the kinetic model. Steam methane reforming simulation hydrogen production hysys tutorial p sims. The kinetics of catalytic steam reforming of methane over an niysz anode of a solid oxide fuel cell sofc have been investigated with the cell placed in a stack configuration. The process involves reforming natural gas in a continuous catalytic process in which the major reaction is the formation of carbon monoxide and hydrogen from methane and steam. Steam reforming of methane in a synthesis gas from biomass. Methane steam reforming reaction behaviour in a packed.
Coupled simulations in steam methane reformers using cfd. The reaction mechanism consists of 52 reactions with 6 gas phase species and surface species. Here the kinetics of methane steam reforming over a rhodiumbased catalyst is. Steam methane reforming over nibased pellettype and ptnial2o3 structured platetype catalyst. May 19, 2011 steam methane reforming simulation hydrogen production hysys tutorial p sims. Methane steam reforming on solid catalysts is the wellestablished commercial process for the production of hydrogen and synthesis gas.
In order to decrease the degree of conversion, a single cell stack with reduced area was used. Coupled simulations in steam methane reformers using cfd and. Bradford and vannice studied the mechanism and kinetics of dry reforming. Steam and hydrocarbon enter the reactor as feedstock, and hydrogen and carbon dioxide are generated at the end of the process. Kinetics providing detailed information of elementary reaction steps for this. In addition to the maturity of the technology, natural gas reforming is also the most economical among all hydrogen production pathways. Langmuir hinshelwood lh kinetics, first order fo reaction with respect to methane, and power law pl expressions with respect to the composing gases. Methane steam reforming an overview sciencedirect topics.
Pdf rate equation of steammethane reforming reaction on ni. Reaction kinetics of the co2 reforming of methane mark. A comparison of 11 kinetics based on both industrial steam methane reforming catalysts and niysz for sofcs showed that they 4. Pdf kinetics study and modelling of steam methane reforming. In general there are two approaches to internal reforming, and these are usually referred to as direct dir and indirect iir internal reforming. Pdf surface reaction kinetics of steam and co2reforming. Due to its maturity, high efficiency, and relatively low cost, steam reforming is considered a viable. The chemical kinetics for steam reforming was found in 59. Pdf kinetic rate data for steam methane reforming smr coupled with water gas shift wgs. In the overall steam methane reforming smr reaction, methane reacts with steam at high temperatures and moderate pressures in catalystfilled tubes to generate synthesis gas, a mixture of hydrogen, carbon monoxide and some carbon dioxide. On the catalytic aspects of steammethane reforming a.
Thermodynamic analysis helped in reducing the number of possible mechanisms. Methane steam reforming over an niysz solid oxide fuel cell anode in stack configuration d. The superheated steam is mixed with natural gas in the reforming reaction, producing hydrogen gas and carbon monoxide. Surface reaction kinetics for oxidation and reforming of. May 01, 2010 in the overall steam methane reforming smr reaction, methane reacts with steam at high temperatures and moderate pressures in catalystfilled tubes to generate synthesis gas, a mixture of hydrogen, carbon monoxide and some carbon dioxide. Onsite hydrogen generation by steam methane reforming.
Computational investigation of thermochemistry and kinetics. In order to produce valuable syngas, industrial processes of dry reforming of methane and steam reforming of methane must be further developed. The reaction pathways of methane steam reforming on nickel catalyst are described 34 elementary steps as following, adsorption of reactant r1r2, activation of methane without oxygen r3r10, activation of methane with oxygen r11r18, dissociation of water r19r22 and the surface reaction to. Advanced modelling and optimisation of natural gas. Various rate models were fitted to the experimental data by numerically integrating the rate equations. Even in steamreforming, air can advantageously be added to the reaction system, as steamreforming is extremely endothermic at high temperatures.
Computational investigation of thermochemistry and. The kinetics of methane steam reforming over a ni o catalyst. Steam reforming is endothermicthat is, heat must be supplied to the process for the reaction to proceed. Title rate equation of steammethane reforming reaction on. Kinetics providing detailed information of elementary reaction steps for this system, namely micro kinetics, has not yet been fully addressed. Methane steam reforming kinetics for a rhodiumbased catalyst. The steammethane reforming reaction on niysz yttriaa stabilized zirconia cermet was experimentally investigated in the temperature range of 650 to 750 we examined the effects of the partial pressures of methane and steam in the supply gas on the reaction rate. In the reforming reaction, natural gas is mixed with steam, heated to over 1,500 degrees fahrenheit, and reacted with nickel catalyst to produce hydrogen h. The feed composition was kept constant to avoid a change in mechanism associated with composition changes. Numerical study of methane dry reforming reaction in a. Steammethane reforming at low temperature on nickelbased catalysts.
Amongst all the available processes steam methane reforming smr is the most established and commonly used process to produce syngas on a large scale. Conventional wisdom showed that steam methane reforming included more than two reactions, through which both co and co 2 were formed during the hydrogen production 5. Steam methane reforming simulation hydrogen production. Methane steam reforming reaction behaviour in a packed bed. In steammethane reforming, methane reacts with steam under 325 bar pressure 1 bar 14. The intrinsic kinetics and diffusion behaviour of methane steam reforming have been investigated in this work. The reaction pathways of methane steam reforming on nickel catalyst are described 34 elementary steps as following, adsorption of reactant r1r2, activation of methane without oxygen r3r10, activation of methane with oxygen r11r18, dissociation of water r19r22 and the surface reaction to form products co 2. The primary reformer is a heat exchanger its function is to heat up process gas catalyst and reaction in the tubes combustion on the shell side dominant heat transfer by radiation. Carbon monoxide from the reforming reaction interacts with water again to produce more hydrogen and carbon dioxide. The kinetics of the co 2 reforming of methane was investigated in the temperature range 700850c at normal pressure with a 1. The reaction system considered in this work is given for reactions as follows. A large number of detailed reaction mechanisms were considered.