02291nas a2200253   4500008004100000022001400041245014900055210006900204260010600273300001200379490000700391520130600398653002701704653002201731653002201753653001701775653002701792653001401819100002301833700001801856700001901874700001901893856012501912       2014                        eng d  a0360-544200aEnhanced kinetics for the clathrate process in a fixed bed reactor in the presence of liquid promoters for pre-combustion carbon dioxide capture0 aEnhanced kinetics for the clathrate process in a fixed bed react  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcJUN  a664-6730 v703 a<p>In this work, we present enhanced kinetics of hydrate formation for the clathrate process in the presence of two liquid promoters namely THF (tetrahydrofuran) and TBAB (tetra-n-butyl ammonium bromide) in a FBR (fixed bed reactor) for pre-combustion capture of CO2. Silica sand was used as a medium to capture CO2 from CO2/H-2 gas mixture by hydrate crystallisation. Experiments were performed at different temperatures (274.2 K and 279.2 K) and 6.0 MPa to determine the total gas uptake, induction time and rate of hydrate formation. The observed trends indicated that higher driving force resulted in higher gas consumption and significantly reduced induction time. For the same driving force, higher gas consumption and shorter induction time was achieved by THF as compared to TBAB. 5.53 mol% THF attained higher gas consumption than 1.0 mol% THF whereas 3.0 mol% TBAB attained lower gas consumption than 0.3 mol% TBAB. A highest gas uptake of 51.95 (+/- 5.183) mmol of gas/mol of water and a highest rate of 51.21(+/- 8.91) mol.min(-1).m(-3) were obtained for 5.53 mol% THF at 6.0 MPa and 279.2 K. Overall, this study indicated better hydrate formation kinetics with the use of THF in an FBR configuration for CO2 capture from a fuel gas mixture. (C) 2014 Elsevier Ltd. All rights reserved.</p>10aCarbon dioxide capture10aClathrate process10aFixed bed reactor10aGas hydrates10aPre-combustion capture10aPromoters1 aBabu, Ponnivalavan1 aHo, Chie, Yin1 aKumar, Rajnish1 aLinga, Praveen  uhttps://library.ncl.res.in/content/enhanced-kinetics-clathrate-process-fixed-bed-reactor-presence-liquid-promoters-pre-000609nas a2200157   4500008004100000245010700041210006900148260000800217300001000225490000800235100001900243700001900262700001900281700001900300856013200319       2015                        eng d00aEnhanced carbon dioxide hydrate formation kinetics in a fixed bed reactor filled with metallic packing0 aEnhanced carbon dioxide hydrate formation kinetics in a fixed be  cJAN  a78-850 v1221 aKumar, Asheesh1 aSakpal, Tushar1 aLinga, Praveen1 aKumar, Rajnish  uhttps://library.ncl.res.in/content/enhanced-carbon-dioxide-hydrate-formation-kinetics-fixed-bed-reactor-filled-metallic-packing01808nas a2200181   4500008004100000245014400041210006900185260000800254300001400262490000700276520110100283100001901384700002701403700002601430700001901456700001901475856013201494       2016                        eng d00aEffect of additives on formation and decomposition kinetics of methane clathrate hydrates: application in energy storage and transportation0 aEffect of additives on formation and decomposition kinetics of m  cNOV  a2160-21670 v943 aMethane gas storage and transportation via clathrate hydrates is proposed to be a potential solution for large-scale energy storage. In this work, we study the formation and decomposition kinetics of methane hydrates (MH) in a laboratory-scale unstirred crystallizer. The present investigation demonstrates comparative studies of hydrate formation and dissociation kinetics in the presence of tetrahydrofuran (55.6 and 27.8mmol/mol, 5.56 and 2.78mol% THF) and sodium dodecyl sulphate (1mg/g, 0.1wt% SDS). Moreover, the storage capacity and hydrate formation kinetics in both the systems are discussed. In a recent work, enhanced methane hydrate growth in the presence of THF at close to atmospheric conditions was demonstrated. The emphasis of the current work is to study the stability of hydrates to understand dissociation kinetics by measuring the rate of hydrate decomposition at different temperatures. Hydrate stability measurements were performed at -8, -3, 2, 10, and 20 degrees C to study the decomposition rates of MH and self-preservation in presence of the two additives THF and SDS.1 aKumar, Asheesh1 aKushwaha, Omkar, Singh1 aRangsunvigit, Pramoch1 aLinga, Praveen1 aKumar, Rajnish  uhttps://library.ncl.res.in/content/effect-additives-formation-and-decomposition-kinetics-methane-clathrate-hydrates-application02922nas a2200265   4500008004100000022001400041245013800055210006900193260009900262300001200361490000800373520191900381653002102300653002402321653001902345653001502364653002002379653002202399100002902421700001802450700001902468700002602487700001902513856012402532       2016                        eng d  a0016-236100aEnhanced clathrate hydrate formation kinetics at near ambient temperatures and moderate pressures: Application to natural gas storage0 aEnhanced clathrate hydrate formation kinetics at near ambient te  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLANDbELSEVIER SCI LTDcOCT  a907-9190 v1823 a<p>SNG (solidified natural gas) technology via clathrate hydrates is a potential method for large scale stationary storage of natural gas. Clathrate hydrate formation kinetics in presence of methane and 5.6 mol% tetrahydrofuran (THF) was investigated in an unstirred reactor configuration at moderate pressure and temperature conditions. It is well known that the presence of THF generally improves the thermodynamic stability of the resulting hydrate. In order to study the scale-up potential of this approach, kinetics of hydrate growth at temperatures close to ambient conditions and moderate pressures is required. Hydrate formation experiments were performed at three different temperatures - 283.2 K, 288.2 K and 293.2 K and at experimental pressures of 7.2 MPa, 5.0 and 3.0 MPa. Further, we report a synergistic effect of kinetic promotion of mixed methane hydrate formation by coupling THF and sodium dodecyl sulfate (SDS) at 293.2 K. For the first time, we observe rapid mixed methane/THF hydrate formation kinetics at 293.2 K in presence of just 100 ppm sodium dodecyl sulfate surfactant with methane gas uptake of 3.45 (+/- 0.17) kmol/m(3) of water in 1 h. This is also the first study to demonstrate such rapid hydrate formation kinetics with significant methane storage capacity at temperature of 293.2 K (closer to the ambient temperature). Further, substantial methane gas uptake of 3.52 (+/- 0.13) kmol/m(3) of water is possible even at reduced experimental pressure of 3.0 MPa and 283.2 K in 2 h. Minimal energy requirement in an unstirred reactor for mixed methane/THF hydrate formation storage can propel the SNG technology for large scale commercial deployment. Further improvement in the process can be achieved by optimizing the cooling requirement through innovative reactor design and operating the process in a semi-batch or continuous mode. (C) 2016 Elsevier Ltd. All rights reserved.</p>10aMethane hydrates10aNatural gas storage10aRapid kinetics10asurfactant10aTetrahydrofuran10aUnstirred reactor1 aVeluswamy, Hari, Prakash1 aKumar, Sharad1 aKumar, Rajnish1 aRangsunvigit, Pramoch1 aLinga, Praveen  uhttps://library.ncl.res.in/content/enhanced-clathrate-hydrate-formation-kinetics-near-ambient-temperatures-and-moderate01692nas a2200169   4500008004100000245014600041210006900187260000800256300001600264490000800280520102800288100001901316700002001335700001901355700001901374856012901393       2016                        eng d00aExperimental investigation to elucidate why tetrahydrofuran rapidly promotes methane hydrate formation kinetics: applicable to energy storage0 aExperimental investigation to elucidate why tetrahydrofuran rapi  cDEC  a29062-290680 v1203 aMethane storage as SNG (solidified natural gas) in the form of clathrate hydrates is an emerging, economically feasible and environmentally benign technology for large scale storage. Mixed tetrahydrofuran (THF)-methane (CH4) hydrates offer a paradigm shift to milder storage conditions and faster hydrate formation kinetics, providing a promising scenario to scale up the SNG technology. In this work, we synthesize mixed THF-CH4 hydrates in a high pressure microdifferential scanning calorimeter (HP mu-DSC) to elucidate the two-step hydrate formation mechanism of mixed THF-CH4 hydrate identifying the synergism between THF and CH4. Heat flow change during hydrate formation and dissociation of mixed THF-CH4 hydrates formed in the presence of 5.56 mol % THF (stoichiometric composition) were monitored. The two step-mechanism of mixed THF-CH4 hydrate formation was further confirmed by the pressure-temperature profile and visual observations with a sample volume scale -up of about 350 times that of mu-DSC experiments.1 aKumar, Asheesh1 aDaraboina, Nagu1 aKumar, Rajnish1 aLinga, Praveen  uhttps://library.ncl.res.in/content/experimental-investigation-elucidate-why-tetrahydrofuran-rapidly-promotes-methane-hydrate