Methane migration

The cold seeps of methane migration along the geologic faults or permeable stratigraphic horizons provide concentrations in excess of... 

Coupled coal-methane-water process has been an active research area in China for a long time due to its utmost importance to mine safety and productivity and the traditional importance of coal mining in Chinese energy industry. In this review only some of the recent works on mathematical modelling on methane migration and water burst problems are highlighted due to space limit. 

The methane migration during coal mining is caused by loss of the in-situ equilibrium between the coal skeleton stress and methane pressure. The interactions between coal deformation and methane migration have several aspects effective stress change in coal seams due to excavation and mining, porosity change and methane content increase,... 

Zhao (1994) presented a model of coupled coal deformation and methane migration based on a consolidation theory of elastic medium with Darcy fluid flow and the Terzaghi effective stress law, and its numerical solution technique and applications to practical problems. Works using similar approaches were also reported in Liang et al. (1995,1996), Sun and Xian (1999), Ding et al. 

Methane migrated into a house via a backfilled mineshaft in Haydock, Lancashire, UK (Barry and Raybould, 1988)... 

Historically there have also been incidents of methane migrating from coal mines and causing explosions in coal mining areas in the UK. 

Box 4.3 Estimate of methane migration in groundwater (Hooker and Bannon, 1993)... 

Q is the volume of methane migrating from the source through this pathway. 

With 4,4-diarylcyclohexenones, the di-Tc-methane rearrangement occcurs. In compounds in which the two aryl groups are substituted differently, it is found that substituents which stabilize radical character favor migration. Thus, the p-cyanophenyl substituent migrates in preference to the phenyl substituent in 4 ... 

The unobserved di-ir-methane rearrangement and the observed a + n hydrogen migration route are as follows ... 

Hixson<27) prepared the deuterio compound (31) and found that photolysis produced only compound (32) resulting from a di-n--methane rearrangement and not from a hydrogen migration ... 

Propose an explanation of why the photorearrangement of compound (14) takes place via a hydrogen migration while the rearrangement of compound (30) takes place via a di-ir-methane reaction. 

Again the di-7r-methane reaction is regiospecific but this time it is competing with phenyl migration,... 

There are a number of major industrial problems in the operation of the steam reforming of methane. These include the formation of carbon on the surface of the catalyst, the sulphidation of the catalyst by the H2S impurity in commercial natural gas, and the decline of catalytic activity due to Ostwald ripening of the supported catalyst particles by migration of catalyst atoms from the smaller to the larger particles, as the temperature is increased. A consideration of the thermodynamics of the principal reaction alone would suggest that the reaction shifts more favourably to the completion of the reaction as the temperature is increased. 

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