Methan, methane

Feedstocks are natural gas, refinery fuel gas, LPG and paraffinic naphthas. After elimination of CO2, the last traces of contaminants are converted to methane (methanation) or eliminated by adsorption on molecular sieves (PSA process). 

This reaction is an undesirable side reaction in the manufacture of hydrogen but utilised as a means of removing traces of carbon monoxide left at the end of the second stage reaction. The gases are passed over a nickel catalyst at 450 K when traces of carbon monoxide form methane. (Methane does not poison the catalyst in the Haber process -carbon monoxide Joes.)... 

When we consider sources of methane we have to add old methane methane that was formed millions of years ago but became trapped beneath the earth s surface to the new methane just de scribed Firedamp an explosion hazard to miners oc curs in layers of coal and is mostly methane Petroleum deposits formed by microbial decomposi tion of plant material under anaerobic conditions are always accompanied by pockets of natural gas which IS mostly methane... 

Chlorination of Methane. Methane can be chlorinated thermally, photochemicaHy, or catalyticaHy. Thermal chlorination, the most difficult method, may be carried out in the absence of light or catalysts. It is a free-radical chain reaction limited by the presence of oxygen and other free-radical inhibitors. The first step in the reaction is the thermal dissociation of the chlorine molecules for which the activation energy is about 84 kj/mol (20 kcal/mol), which is 33 kJ (8 kcal) higher than for catalytic chlorination. This dissociation occurs sufficiendy rapidly in the 400 to 500°C temperature range. The chlorine atoms react with methane to form hydrogen chloride and a methyl radical. The methyl radical in turn reacts with a chlorine molecule to form methyl chloride and another chlorine atom that can continue the reaction. The methane raw material may be natural gas, coke oven gas, or gas from petroleum refining. 

An analogous series of hydrocarbons, and one of the simplest, are the compounds known as the alkanes. In this series, the names of all the compounds end in -ane. The first compound in this series is methane. Methane s molecular formula is CH. Methane is a gas and is the principal ingredient in the mixture of gases known as natural gas. The next compound is this series is ethane, whose molecular formula is CjHj. It is also a gas present in natural gas, although in a much lower percentage than methane. The difference in the molecular formulas of methane and ethane is one carbon and two hydrogen atoms. 

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 ... 

It has been proposed that wood alcohol, CH3OH, a relatively inexpensive fuel to produce, be decomposed to produce methane. Methane is a natural gas commonly used for heating homes. Is foe decomposition of wood... 

They used a Ni-containing catalyst. In contrast to steam reforming of methane, methane partial oxidation is exothermic. However, the partial oxidation requires pure oxygen, which is produced in expensive air separation units that are responsible for up to 40% of the cost of a synthesis gas plant (2) (in contrast, the steam reforming process does not require pure oxygen). Therefore, the catalytic partial oxidation of methane did not attract much interest for nearly half a century, and steam reforming of methane remained the main commercial process for synthesis gas manufacture. 

Methane v Methane o Methane Methane Propane < Ethane > Acetylene Hydrogen a Carbon Monoxide... 

Stage 3 shifts the source of hydrocarbon for transportation and chemicals to methane. Methane currently is reformed at elevated temperatures and pressures to synthesis gas. This mixture of hydrogen and carbon monoxide can then be converted via the well-known technologies of methanol synthesis and Fischer-Tropsch synthesis to eventually produce a variety of chemicals and fuels. In this stage, focus... 

The presence of clusters of adsorbates has already been discussed for single-atom adsorbates, and Demontis and coworkers addressed this issue for methane (65). From the methane-methane RDF, clear evidence for... 

Adsorption isotherms of methane in silicalite have also been predicted in a number of calculation studies (62, 155, 156). Goodbody et al. (62) predicted a heat of adsorption of 18 kJ/mol and simulated the adsorption isotherm up to 650 bar. From the adsorption isotherm, they found that the sinusoidal pore volume contains more methane molecules at all pressures. Snurr et al. (155) performed GC-MC and MD simulations over a wide range of occupancies at several temperatures. The intermolecular zeolite-methane potential parameters were taken from previous MD studies (11, 87) and the methane-methane parameters from MD simulations were adjusted to fit experimental results for liquid methane (157). Electrostatic contributions were neglected on account of the all-silica framework, and methane was represented by a rigid, five-center model. 

We will explain how to do this by taking the specific example of methane. Methane has a central carbon atom which is a-bonded to four hydrogen atoms with each a-bond pointing to one of the comers of a tetrahedron. We therefore require four hybrid orbitals on the carbon atom which similarly point to the comers of a tetrahedron. Since the four bonds are indistinguishable, the four hybrids must be equivalent, that is to say they must be identical in all respects except for their orientation. For the reasons given in 11-2, they will be taken to be linear combinations of the atomic orbitals of carbon, which are... 

Vapor pressure of crude oils is primarily influenced by the presence or absence of light and intermediate hydrocarbons, particularly methane. Methane has much more effect than the same quantity of ethane, ethane more than propane, etc. The composition of a crude oil having a vapor pressure of 10 ... 

FIGURE 3.12 Methane-methane radial distribution functions calculated from successive 0.9 ns portions of the simulation, indicating ordering of the methane molecules during hydrate nucleation. (Reproduced from Moon, C., Taylor, P.C., Rodger, P.M., J. Am. Chem. Soc., 125, 4706 (2003). With permission from the American Chemical Society.)... 

In situ o — Rising 0 — Recycled methane f methane methane... 

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