Methane reaction with steam

After this preliminary study, we measured the rates of methane reaction with steam (i.e., r values in the r+ > r region), and the rates of carbon monoxide hydrogenation [i.e., ( —r) values in the r+ < region] at 470, 530, 600, and 700°C (84). In these experiments the PCH4 and Pco values did not exceed 0.2 and 0.1 atm, respectively therefore, (27 7) and (278) were applicable. Variations in catalytic activity were taken into account on the basis of control experiments. 

Chemical Use. Both natural gas and natural gas Hquids are used as feedstocks in the chemical industry. The largest chemical use of methane is through its reactions with steam to produce mixtures of carbon monoxide and hydrogen (qv). This overall endothermic reaction is represented as... 

Na.tura.1 Ga.s Reforma.tion. In the United States, most hydrogen is presently produced by natural gas reformation or methane—steam reforming. In this process, methane mixed with steam is typically passed over a nickel oxide catalyst at an elevated temperature. The reforming reaction is... 

The synthesis gas for methanation, containing hydrogen and carbon oxides, is produced by gasification of coal by partial oxidation and/or by the reaction with steam. 

Steam, at high temperatures (975-1375 K) is mixed with methane gas in a reactor with a Ni-based catalyst at pressures of 3-25 bar to yield carbon monoxide (CO) and hydrogen (H ). Steam reforming is the process by which methane and other hydrocarbons in natural gas are converted into hydrogen and carbon monoxide by reaction with steam over a nickel catalyst on a ceramic support. The hydrogen and carbon monoxide are used as initial material for other industrial processes. 

The SMR process consists of two steps. The first is the reformation process in which methane mixed with steam is passed over a catalyst bed at high temperature and pressure to form a mixture of hydrogen and carbon monoxide (reaction 1.1), called syngas. The second step is the shift reaction in which carbon monoxide from the first stage reacts with additional steam to release carbon dioxide and more hydrogen (reaction 1.2). 

All these cells are anodically combusting hydrogen, although MCFCs and SOFCs may be supplied with methane or carbon monoxide from which by internal reforming and/or shift reaction with steam within the cell the hydrogen may be generated in situ (98-100). 

Light hydrocarbons ranging from natural gas (methane) to naphtha (max. Cn) undergo reaction with steam over a catalyst according to Equation (35) which is usually... 

Hydrogen is manufactured from methane by either steam reforming (reaction with steam) or partial oxidation (reaction with oxygen). Both processes are endothermic. What reactor temperature and pressure would you expect to be optimal for these processes What constraints might apply ... 

Methane reacts with steam in the presence of a supported nickel catalyst to produce a mixture of CO and H2, also known as synthesis gas or syngas as represented by Equation 2.1. This reaction is also referred to as steam methane reforming (SMR) and is a widely practiced technology for industrial production of H2. However, the SMR is not really just one reaction as indicated in Equation 2.1 but involves contributions from several different catalyzed reactions such as water-gas shift... 

Hydrogenation of oxides of carbon and the reverse reaction (e.g., methane reforming with steam) Nickel... 

Methane is reformed by reaction with steam according to reactions Ri - R4 on page 632. Determine the equilibrium composition at 600 K, 2 bar, of a reaction mixture whose feed consists of a methane-water mixture at molar ratio 1 2. 

P.3.2.3 Kinetics The reaction given by Equation 9.22a describes methane reforming with steam, whereas Equation 9.22b describes the water-gas shift reaction. The kinetic expression used for the CH4 reforming reaction shall be given by the following simple relation ... 

On-ceU reforming aUows the SOFC to run on alternative fuels and helps to reduce the temperatures of the SOFC. In the case of steam-methane reforming, reformation occurs on the surface of the Ni in a Ni-YSZ anode. The methane reacts with steam to form H2 and CO by an endothermic reaction ... 

Avd et cd. investigated combined catalytic combustion and steam reforming but also quasi-autothermal reforming of methane in fixed catalyst beds. Two different catalyst formulations were used to combine the combustion reaction with steam reforming, namely a nickel catalyst for steam reforming and a platinum catalyst for methane combustion. The two catalysts were assumed to be placed into two serial... 

Hydrocarbons are converted into a mixture of hydrogen and oxides of carbon by reaction with steam over steam reforming catalysts. The reforming reaction is endothermic and the catalysts are packed into narrow tubes, which are heated in a furnace. The reforming furnace is commonly known as a reformer. An efficient methane steam reforming process was developed by 1936 and was first used on a large scale in North America during World War Two as shown in Ta-... 

The Fischer-Tropsch reaction is essentially that of Eq. XVIII-54 and is of great importance partly by itself and also as part of a coupled set of processes whereby steam or oxygen plus coal or coke is transformed into methane, olefins, alcohols, and gasolines. The first step is to produce a mixture of CO and H2 (called water-gas or synthesis gas ) by the high-temperature treatment of coal or coke with steam. The water-gas shift reaction CO + H2O = CO2 + H2 is then used to adjust the CO/H2 ratio for the feed to the Fischer-Tropsch or synthesis reactor. This last process was disclosed in 1913 and was extensively developed around 1925 by Fischer and Tropsch [268]. 

Another hydrogenation process utilizes internally generated hydrogen for hydroconversion in a single-stage, noncatalytic, fluidized-bed reactor (41). Biomass is converted in the reactor, which is operated at about 2.1 kPa, 800°C, and residence times of a few minutes with steam-oxygen injection. About 95% carbon conversion is anticipated to produce a medium heat value (MHV) gas which is subjected to the shift reaction, scmbbing, and methanation to form SNG. The cold gas thermal efficiencies are estimated to be about 60%. 

Reduction of sulfur dioxide by methane is the basis of an Allied process for converting by-product sulfur dioxide to sulfur (232). The reaction is carried out in the gas phase over a catalyst. Reduction of sulfur dioxide to sulfur by carbon in the form of coal has been developed as the Resox process (233). The reduction, which is conducted at 550—800°C, appears to be promoted by the simultaneous reaction of the coal with steam. The reduction of sulfur dioxide by carbon monoxide tends to give carbonyl sulfide [463-58-1] rather than sulfur over cobalt molybdate, but special catalysts, eg, lanthanum titanate, have the abiUty to direct the reaction toward producing sulfur (234). 

In a typical PAFC system, methane passes through a reformer with steam from the coolant loop of the water-cooled fuel cell. Heat for the reforming reaction is generated by combusting the depleted fuel. The reformed natural gas contains typically 60 percent H9, 20 percent CO, and 20 percent H9O. Because the platinum catalyst in the PAFC can tolerate only about 0.5 percent CO, this fuel mixture is passed through a water gas shift reactor before being fed to the fuel cell. 

Catalytic methanation is the reverse of the steam reforming reaction. Hydrogen reacts with carbon monoxide and carbon dioxide, converting them to methane. Methanation reactions are exothermic, and methane yield is favored at lower temperatures ... 

Fuel reforming is popular way for hydrogen production for fuel cell use. Hydrocarbons are used for the fuel resource. Methane (CH4) steam reforming process consists of the following two gas phase reactions with various catalysts. 

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