Catalytic methane

Gasification technologies for the production of high heat-value gas do not all depend entirely on catalytic methanation, that is, the direct addition of hydrogen to coal under pressure to form methane. 

Catalytic methanation processes include (/) fixed or fluidized catalyst-bed reactors where temperature rise is controlled by heat exchange or by direct cooling using product gas recycle (2) through wall-cooled reactor where temperature is controlled by heat removal through the walls of catalyst-filled tubes (J) tube-wall reactors where a nickel—aluminum alloy is flame-sprayed and treated to form a Raney-nickel catalyst bonded to the reactor tube heat-exchange surface and (4) slurry or Hquid-phase (oil) methanation. 

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 ... 

Design and Operation of Catalytic Methanation in the HYGAS Pilot Plant... 

Catalytic methanation in the Hygas pilot plant, design and operation of. 123... 

Design and operation of catalytic methanation in the Hygas pilot... 

The use of carbon-based catalysts offers certain advantages over metal catalysts due to their availability, durability, and low cost. In contrast to the metal-based catalysts, carbon catalysts are sulfur resistant and can withstand much higher temperatures. Muradov [98,99] screened a variety of carbon materials and demonstrated that the efficient catalytic methane decomposition can be accomplished over high surface area carbons at temperatures... 

Production of Carbon Filaments by Catalytic Methane Decomposition 176... 

At the outset, this section will address studies related to the catalytic methane decomposition step and then subsequently describe the work undertaken on the combined step-wise reforming (two step) process. 

Catalytic methane decomposition has received considerable attention in recent years. The reaction has been investigated for two main applications (a) production of hydrogen and (b) synthesis of carbon filaments. The important conditions necessary for clean hydrogen production are as follows ... 

Catalytic methanation. This is a process for removing carbon monoxide from gas streams or for producing methane by the reaction... 

A convenient method to produce porous surfaces is the anodic oxidation of aluminum plates. Such microstructured aluminum platelets have been coated by wet impregnation with Pt-, V- and Zr-precursors [35], and tested under catalytic methane combustion conditions. The conversion rate of oxygen followed directly the platinum content in the catalysts. These data were well reproducible even after five different runs. 

Catalytic Methane Combustion and Methods for Sample Preparation... 

In the case of catalytic methane combustion, aluminum was chosen as an appropriate material for the catalyst wafers since anodic oxidation of aluminum can be used to obtain porous surfaces. Such micro structured aluminum platelets were coated by wet impregnation with Pt, V and Zr precursors [50],... 

G. Veser, J. Frauhammer, Modeling steady state and ignition during catalytic methane oxidation in a monolith reactor. Chem. Eng. Sci.,... 

Of particular interest are catalytic methane decomposition reactions producing special (e.g. filamentous) forms of carbon. For example, researchers have reported catalytic decomposition of methane over Ni catalyst at 500°C with the production of hydrogen and whisker carbon26 and concentrated solar radiation was used to thermally decompose methane into hydrogen and filamentous carbon.27 The advantages of this system included efficient heat transfer due to direct irradiation of the catalyst, and C02-free operation. 

A small modification of the above design, in which the catalyst in the form of granules or pellets is placed in an annular basket made of wire mesh fitted close to the reactor wall, has also been examined. The use of such an annular basket-type reactor has been reported by Tajbl et al. (1967), Relyea and Perlmutter (1968), and Lakshmanan and Rouleau (1970). The basic features of this reactor are the same as the ones described above. The reactor has been used to carry out high-pressure, high-temperature catalytic methanation of mixtures of carbon monoxide/hydrogen and carbon dioxide/hydrogen. 

A catalyst composed of 10 wt % nickel on y -alumina is used to promote the catalytic methanation... 

CO is converted to C02 in the HT and LT shift over standard catalysts. C02 is removed in a scrubbing unit, which is normally either the BASF-aMDEA or the UOP-Benfield process. Remaining carbonoxides are reconverted to methane in the catalytic methanation to trace ppm levels. 

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