01906nas a2200241 4500008004100000022001400041245010400055210006900159260011000228300001200338490000700350520101900357653000901376653002301385653002001408653001601428653002101444100001901465700001901484700001501503700001901518856012701537 2015 eng d a0008-404200aMethane hydrate formation in a test sediment of sand and clay at various levels of water saturation0 aMethane hydrate formation in a test sediment of sand and clay at a65 AURIGA DR, SUITE 203, OTTAWA, ON K2E 7W6, CANADAbCANADIAN SCIENCE PUBLISHING, NRC RESEARCH PRESScAUG a874-8810 v933 a

Kinetics of methane hydrate formation with different ratios of silica sand and clay and different water saturations were studied. At suitable temperature and methane gas pressure, water in the void spaces of silica sand packing and intercalated area of clay were converted into hydrate. It was observed that the rate of hydrate formation increases with higher void space in the packing, and addition of clay in test sediment decreases water to hydrate conversion as well as rate of hydrate formation. Maximum water to hydrate conversion of 60.0% was achieved in pure silica sand bed at 75% water saturation. Presence of fine clay particles is expected to reduce the void spaces and thus may hinder effective mass transfer of hydrate forming gases in the bed. However, it is also possible that the bentonite clay used in this work may actually inhibit hydrate growth. Additional experiments in stirred tank reactor were carried out to understand the inhibiting effect of bentonite clay for hydrate formation.

10aclay10aformation kinetics10amethane hydrate10aSilica sand10awater saturation1 aKumar, Asheesh1 aSakpal, Tushar1 aRoy, Sudip1 aKumar, Rajnish uhttps://library.ncl.res.in/content/methane-hydrate-formation-test-sediment-sand-and-clay-various-levels-water-saturation-002325nas a2200289 4500008004100000020004100041245008300082210006900165260012400234520125600358653001901614653002001633653003001653653002701683653001601710100001601726700003101742700001901773700002301792700002201815700002901837700001801866700001301884700001501897700001401912856010901926 2016 eng d a978-81-322-2773-1; 978-81-322-2771-700aRole of Rhamnolipid: A biosurfactant in methane gas hydrate formation kinetics0 aRole of Rhamnolipid A biosurfactant in methane gas hydrate forma a7th Floor, Vijaya Building, 17, Barakhamba Rd, New Delhi, 110 001, IndiabSardar Swaran Singh Natl Inst Bio-EnergycFEB3 a

Naturally occurring methane gas hydrate is a vast source of methane gas which is trapped in crystalline ice-like structure present in permafrost regions and under the sea in outer continental margins. It is purposed that total amount of carbon in the form of methane hydrates is almost twice the carbon content in all the fossil fuel reserves put together, and hence these are supposed to be the future potential energy resource. This paper investigates the laboratory investigations on effect of a biosurfactant rhamnolipid on methane hydrate formation kinetics. Rhamnolipid was produced by Pseudomonas aeruginosa strain A11. The presence of P. aeruginosa has been reported in Gulf of Mexico gas hydrate samples. Biosurfactant reduced the surface tension of water from 72 to 36 mN/m with CMC of 70 mg/L. The biosurfactant dose is studied at two different concentrations in the solution at 100 and 1000 ppm. Kinetic of hydrate formation and growth is compared at 0, 100, and 1000 ppm of rhamnolipid showing that rhamnolipid acts as a hydrate promoter at these concentrations. Thus, small dosages of rhamnolipids produced by P. aeruginosa strain A11 must clearly affect the gas hydrate formation kinetics in natural sites (as in Gulf of Mexico).

10aInduction time10amethane hydrate10aPotential energy resource10aPseudomonas aeruginosa10aRhamnolipid1 aArora, Amit1 aCameotra, Swaranjit, Singh1 aKumar, Rajnish1 aSingh, Anil, Kumar1 aKumar, Pushpendra1 aBalomajumder, Chandrajit1 aLaik, Sukumar1 aKumar, S1 aKhanal, SK1 aYadav, YK uhttps://library.ncl.res.in/content/role-rhamnolipid-biosurfactant-methane-gas-hydrate-formation-kinetics02708nas a2200313 4500008004100000022001400041245011000055210006900165260000900234300001100243490000800254520170900262653001601971653001301987653001902000653002002019653002102039653002402060653001202084100002602096700002202122700002002144700002402164700002102188700002002209700001502229700001902244856013102263 2019 eng d a0306-261900aMethane recovery from marine gas hydrates: a bench scale study in presence of low dosage benign additives0 aMethane recovery from marine gas hydrates a bench scale study in cNOV  a1135660 v2533 a

De-pressurization is one approach which has been found to be economically feasible for methane recovery from marine hydrates. Hydrate dissociation being an endothermic process suggests that de-pressurization alone would not be sufficient and some additional stimulation would be required for sustained production from one such reservoir. Thermal stimulation may overcome the challenge posed by the endothermic dissociation process; however, economically it may not be ideal. A possible way out is to use thermal stimulation, but at relatively low temperatures as compared to conventional practice. This would be economical and can be accomplished in the presence of small doses of additives mixed in with the water stream used for thermal stimulation. In the present study, a number of benign additives were identified which when used in low concentrations enhance the kinetics of methane hydrate dissociation compared to pure water. Additives were first shortlisted from a wide potential pool using quantum mechanical calculations. These additives were later tested for their efficacy in stirred tank reactor to quickly identify the best additives for the job and few selected additives were then studied in a larger bench scale setup (fixed bed configuration) where they were injected in the form of an additive-water stream to dissociate already formed hydrates. Factors such as toxicity of the additive, fluidity of additive-water stream, foam formation on mixing of additive with water, etc. were also taken into account. An energy and efficiency analysis revealed that reported additives enhance the energy ratio and thermal efficiency of the process as compared to pure water stimulation.

10aBench scale10akinetics10aMarine hydrate10amethane hydrate10aMethane recovery10aNatural gas hydrate10aProcess1 aBhattacharjee, Gaurav1 aChoudhary, Nilesh1 aBarmecha, Vivek1 aKushwaha, Omkar, S.1 aPande, Nawal, K.1 aChugh, Parivesh1 aRoy, Sudip1 aKumar, Rajnish uhttps://library.ncl.res.in/content/methane-recovery-marine-gas-hydrates-bench-scale-study-presence-low-dosage-benign-additives