Role of Critical Gas Saturation in Methane Production from Hydrate Dissociation at the Pore-Network Scale

2004 ◽  
Author(s):  
Ioannis N. Tsimpanogiannis ◽  
Peter C. Lichtner
Keyword(s):  
Methane Production ◽  
Pore Network ◽  
Hydrate Dissociation ◽  
Gas Saturation ◽  
Network Scale ◽  
Critical Gas Saturation

scholarly journals Study of the Critical Pore Radius That Results in Critical Gas Saturation during Methane Hydrate Dissociation at the Single-Pore Scale: Analytical Solutions for Small Pores and Potential Implications to Methane Production from Geological Media

Energies ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 210
Author(s):  
Ioannis Nikolaos Tsimpanogiannis ◽  
Emmanuel Stamatakis ◽  
Athanasios Konstantinos Stubos
Keyword(s):  
Porous Media ◽  
Analytical Solutions ◽  
Methane Production ◽  
Methane Hydrate ◽  
Pore Radius ◽  
Hydrate Dissociation ◽  
Gas Saturation ◽  
Dissociation Temperature ◽  
Critical Gas Saturation ◽  
Pore Body

We examine the critical pore radius that results in critical gas saturation during pure methane hydrate dissociation within geologic porous media. Critical gas saturation is defined as the fraction of gas volume inside a pore system when the methane gas phase spans the system. Analytical solutions for the critical pore radii are obtained for two, simple pore systems consisting of either a single pore-body or a single pore-body connected with a number of pore-throats. Further, we obtain critical values for pore sizes above which the production of methane gas is possible. Results shown in the current study correspond to the case when the depression of the dissociation temperature (due to the presence of small-sized pores; namely, with a pore radius of less than 100 nm) is considered. The temperature shift due to confinement in porous media is estimated through the well-known Gibbs-Thompson equation. The particular results are of interest to geological media and particularly in the methane production from the dissociation of natural hydrate deposits within off-shore oceanic or on-shore permafrost locations. It is found that the contribution of the depression of the dissociation temperature on the calculated values of the critical pore sizes for gas production is limited to less than 10% when compared to our earlier study where the porous media effects have been ignored.

Deterioration caused by dimensional change in stone (EBD pathology): the role of the organic matter — pore network — salt combination

2018 ◽  
Vol 34 ◽  
pp. 198-207
Author(s):  
Josep Gisbert Aguilar ◽  
Oscar Buj Fandos ◽  
Blanca Bauluz Lázaro ◽  
Fausto Peddis ◽  
Francesco Cuccuru
Keyword(s):  
Organic Matter ◽  
Dimensional Change ◽  
Pore Network

scholarly journals Increasing sulfate levels show a differential impact on synthetic communities comprising different methanogens and a sulfate reducer

2019 ◽  
Vol 16 (154) ◽  
pp. 20190129 ◽  
Author(s):  
Jing Chen ◽  
Matthew J. Wade ◽  
Jan Dolfing ◽  
Orkun S. Soyer
Keyword(s):  
Microbial Communities ◽  
Methane Production ◽  
System Stability ◽  
Sulfate Reducer ◽  
Differential Impact ◽  
Sulfate Reducers ◽  
Hydrogenotrophic Methanogens ◽  
The Stability ◽  
The Impact

Methane-producing microbial communities are of ecological and biotechnological interest. Syntrophic interactions among sulfate reducers and aceto/hydrogenotrophic and obligate hydrogenotrophic methanogens form a key component of these communities, yet, the impact of these different syntrophic routes on methane production and their stability against sulfate availability are not well understood. Here, we construct model synthetic communities using a sulfate reducer and two types of methanogens representing different methanogenesis routes. We find that tri-cultures with both routes increase methane production by almost twofold compared to co-cultures and are stable in the absence of sulfate. With increasing sulfate, system stability and productivity decreases and does so faster in communities with aceto/hydrogenotrophic methanogens despite the continued presence of acetate. We show that this is due to a shift in the metabolism of these methanogens towards co-utilization of hydrogen with acetate. These findings indicate the important role of hydrogen dynamics in the stability and productivity of syntrophic communities.

Methane production in cattle and sheep fed grass silage plus a barley based concentrate

1994 ◽  
Vol 1994 ◽  
pp. 126-126
Author(s):  
C.J. Newbold ◽  
A.R. Moss ◽  
G.S. Mollinson
Keyword(s):  
Global Warming ◽  
Greenhouse Gases ◽  
Methane Production ◽  
Limited Attention ◽  
Grass Silage ◽  
Cattle And Sheep

Increasing concern over the role of greenhouse gases in global warming has lead to a renewed interest in the production of methane by ruminants. Sheep are routinely used to study digestibility, however their use as a model to study methane production by cattle has received only limited attention (Blaxter and Wainman, 1964). The objective of the current study was to establish whether differences in methane production exist between sheep and cattle and to measure the magnitude of these differences under various dietary situations.

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