02238nas a2200253   4500008004100000022001400041245012400055210006900179260010600248300001200354490000700366520128200373653002701655653001701682653001701699653001901716653001901735653002201754100002101776700002301797700001901820700001901839856012601858       2013                        eng d  a0360-544200aHBGS (hydrate based gas separation) process for carbon dioxide capture employing an unstirred reactor with cyclopentane0 aHBGS hydrate based gas separation process for carbon dioxide cap  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcDEC  a252-2590 v633 a<p>The effect of CP (cyclopentane) as a promoter/additive, in the HBGS (hydrate based gas separation) process for pre-combustion gas mixture was investigated by employing an unstirred reactor configuration. Gas uptake measurements were performed at two different temperatures (275.7 K and 285.7 K) and at an experimental pressure of 6.0 MPa to determine the kinetics of hydrate formation. Experiments were conducted with three different volumes (7.5, 15 and 22 ml) of CP and based on induction time and the rate of hydrate growth, 15 ml of CP was determined to be the optimal volume for carbon dioxide capture at 6.0 MPa and 275.7 K. In addition, the effect of a kinetic promoter, SDS (sodium dodecyl sulfate), was investigated. Surprisingly, no improvement in kinetic performance was observed at 6.0 MPa and 275.7 K in the presence of SDS and CP. From the study, it was found that at the optimal 15 ml CP (CP layer thickness of 1.8 mm), the average composition of carbon dioxide in the hydrate phase was 90.36 mol% with a separation factor of 17.82. Furthermore, the unstirred reactor also yielded better kinetic performance over the stirred tank reactor with the unstirred reactor having a 2.28 times higher average gas uptake. (C) 2013 Elsevier Ltd. All rights reserved.</p>10aCarbon dioxide capture10aCyclopentane10aGas hydrates10aGas separation10aPre-combustion10aUnstirred reactor1 aHo, Leong, Chuan1 aBabu, Ponnivalavan1 aKumar, Rajnish1 aLinga, Praveen  uhttps://library.ncl.res.in/content/hbgs-hydrate-based-gas-separation-process-carbon-dioxide-capture-employing-unstirred-001987nas a2200265   4500008004100000022001400041245010200055210006900157260009000226300001000316490000700326520103300333653002701366653001701393653001901410653002201429653001901451653001901470100002301489700001501512700002901527700001901556700001901575856012701594       2013                        eng d  a0021-961400aHydrate phase equilibrium of ternary gas mixtures containing carbon dioxide, hydrogen and propane0 aHydrate phase equilibrium of ternary gas mixtures containing car  a24-28 OVAL RD, LONDON NW1 7DX, ENGLANDbACADEMIC PRESS LTD- ELSEVIER SCIENCE LTDcJUN  a58-630 v613 a<p>Hydrate phase equilibrium of the ternary guest mixtures containing carbon dioxide, hydrogen and propane at two different compositions were determined. Addition of mole composition of 2.5% propane to the fuel gas (CO2 (40%)/H-2 (60%)) mixture reduces the hydrate formation conditions by 66% at the temperature of 278.4 K. A Clausius-Clapeyron plot for the experimental results was plotted and from the slope, the enthalpy of hydrate dissociation was calculated. The enthalpy of dissociation of the mixed hydrate formed from a ternary gas mixture containing mole composition 38.1% CO2, 59.4% H-2 and 2.5% C3H8 was found to be 110 kJ.mol(-1) and hence it was concluded that the mixed hydrate formed structure II (sII) hydrates. Whereas for the ternary gas mixture containing mole composition 80.0% CO2, 18.8% H-2, and 1.2% C3H8, the enthalpy of dissociation of the mixed hydrate was found to be 78 kJ.mol(-1) and hence we believe the mixed hydrate formed structure I (sI) hydrate. (C) 2013 Elsevier Ltd. All rights reserved.</p>10aCarbon dioxide capture10aGas hydrates10aGlobal warming10aPhase equilibrium10aPre-combustion10aThermodynamics1 aBabu, Ponnivalavan1 aYang, Ting1 aVeluswamy, Hari, Prakash1 aKumar, Rajnish1 aLinga, Praveen  uhttps://library.ncl.res.in/content/hydrate-phase-equilibrium-ternary-gas-mixtures-containing-carbon-dioxide-hydrogen-and-002058nas a2200241   4500008004100000022001400041245009300055210006900148260009900217300001200316490000800328520118700336653002701523653002201550653001301572653001501585653001601600100001901616700001901635700001901654700001901673856012401692       2013                        eng d  a0016-236100aInfluence of contact medium and surfactants on carbon dioxide clathrate hydrate kinetics0 aInfluence of contact medium and surfactants on carbon dioxide cl  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLANDbELSEVIER SCI LTDcMAR  a664-6710 v1053 a<p>Carbon dioxide (CO2) hydrate formation kinetic was investigated in a fixed bed crystallizer at constant pressure (3.55 MPa) and temperature (274 K). Porous media of three different silica gels were used, with a mesh size of 60-120, 100-200 and 230-400 having different surface area. The observed trends indicate that silica gel with larger surface area leads to higher gas consumption as well as reduces the induction time. The effect of pore diameter and particle size distribution has already been reported in a previous study [1]. In this study the effect of additives on hydrate formation kinetics were also investigated. The additives studied were nonionic surfactant Tween-80 (T-80), cationic dodecyltrimethylammonium chloride (DTACl) and anionic Sodium Dodecyl Sulphate (SDS). Out of the three surfactants used in this study, SDS was found to be most effective in enhancing the rate of hydrate formation as well as reducing the induction time. The current result shows significant improvement in water to hydrate conversion in silica gel media compared to quiescent water or surfactant-water system under similar conditions. (C) 2012 Elsevier Ltd. All rights reserved.</p>10aCarbon dioxide capture10aClathrate hydrate10akinetics10aSilica gel10aSurfactants1 aKumar, Asheesh1 aSakpal, Tushar1 aLinga, Praveen1 aKumar, Rajnish  uhttps://library.ncl.res.in/content/influence-contact-medium-and-surfactants-carbon-dioxide-clathrate-hydrate-kinetics-002452nas a2200229   4500008004100000022001400041245014500055210006900200260009900269300001200368490000700380520154800387653002701935653001701962653001901979653001901998653001502017100002302032700001902055700001902074856012902093       2013                        eng d  a1750-583600aMedium pressure hydrate based gas separation (HBGS) process for pre-combustion capture of carbon dioxide employing a novel fixed bed reactor0 aMedium pressure hydrate based gas separation HBGS process for pr  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLANDbELSEVIER SCI LTDcSEP  a206-2140 v173 a<p>This work presents an effective medium pressure hydrate based gas separation (HBGS) process for pre-combustion carbon dioxide capture in a novel fixed bed column. 2.5 mol% propane was added to the fuel gas mixture as an additive to decrease the operating pressure of the HBGS process. Hydrate formation kinetics was investigated at three different pressures (4.5, 5.5 and 6.0 MPa respectively) and at 274.15 K. The performance of silica sand and silica gel as a medium was evaluated. In silica sand bed, multiple nucleation events were observed. In silica gel bed, the gas uptake and water conversion to hydrates was significantly low at any given driving force than that obtained in silica sand bed. Experiments at different water saturation levels (50, 75 and 100%) in silica sand bed were investigated at 6.0 MPa and 274.15 K. It was found that at 50% water saturation, gas consumed for hydrate formation and water conversion to hydrates was almost three times that at 100% saturation. Water to hydrate conversions of up to 64.3% was achieved after 4 h of hydrate formation for the 50% water saturated silica sand bed. Our study presents an opportunity to scale up the HBGS process for CO2 capture with enhanced kinetics by employing a fixed bed reactor configuration. Decomposition experiments at a driving force of Delta T of 10 K and 23K were carried out to recover the gas consumed for hydrate formation and it was found that Delta T of 23 K was sufficient to recover the hydrated gas. (C) 2013 Elsevier Ltd. All rights reserved.</p>10aCarbon dioxide capture10aGas hydrates10aGlobal warming10aPre-combustion10aSeparation1 aBabu, Ponnivalavan1 aKumar, Rajnish1 aLinga, Praveen  uhttps://library.ncl.res.in/content/medium-pressure-hydrate-based-gas-separation-hbgs-process-pre-combustion-capture-carbon-002035nas a2200181   4500008004100000022001400041245010300055210006900158260007100227300001400298490000700312520132600319100001501645700002301660700001901683700001901702856013201721       2013                        eng d  a1528-748300aMorphology of carbon dioxide-hydrogen-cyclopentane hydrates with or without sodium dodecyl sulfate0 aMorphology of carbon dioxidehydrogencyclopentane hydrates with o  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAY  a2047-20590 v133 a<p>In this study, effects of cyclopentane (CP) and sodium dodecyl sulfate (SDS) on the hydrate formation morphology were investigated. A gas mixture of 40.0 mol % carbon dioxide and 60.0 mol % hydrogen was used in an unstirred system with subcooling as the driving force. Experimental pressure is at 6.0 MPa and experimental temperatures used are at 275.65 and 277.65 K (Delta T = 15.15 and 13.15 K). Formation of hydrates started at the cyclopentane-liquid water interface. Cloud-like, equiaxed skewed dendritic, equiaxed orthogonal dendritic, long dendritic, and cactus-like crystals could be observed for the experiments in the absence of surfactants. Rapid hydrate formation was observed for the experiments with 0.9 mL CP with or without the presence of surfactants compared to the experiments with 0.45 mL CP system at the same experimental conditions. The addition of SDS had led to a change in the hydrate crystal morphology, forming fiber-like crystals from the hydrate layer. Hydrates had also shown affinity to metal surfaces and tend to grow rapidly because of better heat transfer capacity. Gas uptake measurements were found to correlate well with the morphological observations. On the basis of the morphological observations, the mechanism of the CO2-H-2-CP system in an unstirred system is presented.</p>1 aLim, Yu-An1 aBabu, Ponnivalavan1 aKumar, Rajnish1 aLinga, Praveen  uhttps://library.ncl.res.in/content/morphology-carbon-dioxide-hydrogen-cyclopentane-hydrates-or-without-sodium-dodecyl-sulfate-001724nas a2200169   4500008004100000022001400041245012200055210006900177260007100246300001600317490000700333520102400340100002301364700001901387700001901406856012901425       2013                        eng d  a0013-936X00aNew porous material to enhance the kinetics of clathrate process: application to precombustion carbon dioxide capture0 aNew porous material to enhance the kinetics of clathrate process  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcNOV  a13191-131980 v473 a<p>In this work, the performance of a new porous medium, polyurethane (PU) foam in a fixed bed reactor for carbon dioxide separation from fuel gas mixture using the hydrate based gas separation process is evaluated. The kinetics of hydrate formation in the presence of 2.5 mol % propane as thermodynamic promoter was investigated at 4.5, 5.5, and 6.0 MPa and 274.2 K. Significantly higher gas consumption and water conversion to hydrate was achieved when PU foam was employed. PU foam as a porous medium can help convert 54% of water to hydrate in two hours of hydrate formation. In addition the induction times were very low (&lt;3.67 min at 6.0 MPa). A normalized rate of hydrate formation of 64.48 (+/- 3.82) mol.min(-1).m(-3) was obtained at 6.0 MPa and 274.2 K. Based on a morphological study, the mechanism of hydrate formation from water dispersed in interstitial pore space of the porous medium is presented. Finally, we propose a four step operation of the hydrate based gas separation process to scale up.</p>1 aBabu, Ponnivalavan1 aKumar, Rajnish1 aLinga, Praveen  uhttps://library.ncl.res.in/content/new-porous-material-enhance-kinetics-clathrate-process-application-precombustion-carbon-002025nas a2200229   4500008004100000022001400041245010400055210006900159260010600228300001200334490000700346520114500353653002701498653002301525653001901548653001901567653001901586100002301605700001901628700001901647856012901666       2013                        eng d  a0360-544200aPre-combustion capture of carbon dioxide in a fixed bed reactor using the clathrate hydrate process0 aPrecombustion capture of carbon dioxide in a fixed bed reactor u  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcFEB  a364-3730 v503 a<p>Hydrate based gas separation (HBGS) process with silica sand and silica gel as contact medium was employed to capture CO2 from fuel gas mixture. Gas uptake measurement at three different pressures (7.5, 8.5 and 9.0 MPa) and 274.15 K were conducted for hydrate formation kinetics and overall conversion of water to hydrate, rate of hydrate formation were determined. Water conversion of up to 36% was achieved with silica sand bed compared to 13% conversion in the silica gel bed. Effect of driving force on the rate of hydrate formation and gas consumption was significant in silica sand bed whereas it was found to be insignificant in silica gel bed. Hydrate dissociation experiments by thermal stimulation (at constant pressure) alone and a combination of depressurization and thermal stimulation were carried out for complete recovery of the hydrated gas. A driving force of 23 K was found to be sufficient to recover all the hydrated gas within 1 h. This study indicates that silica sand can be an effective porous media for separation of CO2 from fuel gas when compared to silica gel. (C) 2012 Elsevier Ltd. All rights reserved.</p>10aCarbon dioxide capture10aClathrate hydrates10aGas separation10aGlobal warming10aPre-combustion1 aBabu, Ponnivalavan1 aKumar, Rajnish1 aLinga, Praveen  uhttps://library.ncl.res.in/content/pre-combustion-capture-carbon-dioxide-fixed-bed-reactor-using-clathrate-hydrate-process-002291nas 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-002186nas a2200241   4500008004100000022001400041245009100055210006900146260009900215300001200314490000800326520131600334653001501650653001701665653002201682653002101704653001401725653002101739100002901760700001901789700001901808856011701827       2014                        eng d  a0306-261900aHydrogen storage in clathrate hydrates: Current state of the art and future directions0 aHydrogen storage in clathrate hydrates Current state of the art   aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLANDbELSEVIER SCI LTDcJUN  a112-1320 v1223 a<p>Hydrogen is looked upon as the next generation clean energy carrier, search for an efficient material and method for storing hydrogen has been pursued relentlessly. Improving hydrogen storage capacity to meet DOE targets has been challenging and research efforts are continuously put forth to achieve the set targets and to make hydrogen storage a commercially realizable process. This review comprehensively summarizes the state of the art experimental work conducted on the storage of hydrogen as hydrogen clathrates both at the molecular level and macroscopic level. It identifies future directions and challenges for this exciting area of research. Hydrogen storage capacities of different clathrate structures - sI, sII, sH, sVI and semi clathrates have been compiled and presented. In addition, promising new approaches for increasing hydrogen storage capacity have been described. Future directions for achieving increased hydrogen storage and process scale up have been outlined. Despite few limitations in storing hydrogen in the form of clathrates, this domain receives prominent attention due to more environmental-friendly method of synthesis, easy recovery of molecular hydrogen with minimum energy requirement, and improved safety of the process. (C) 2014 Elsevier Ltd. All rights reserved.</p>10aClathrates10aGas hydrates10aHydrogen hydrates10aHydrogen storage10aPromoters10aStorage capacity1 aVeluswamy, Hari, Prakash1 aKumar, Rajnish1 aLinga, Praveen  uhttps://library.ncl.res.in/content/hydrogen-storage-clathrate-hydrates-current-state-art-and-future-directions-002258nas a2200229   4500008004100000022001400041245015800055210006900213260010600282300001200388490000700400520133500407653002701742653002201769653001701791653002001808100002301828700001701851700001901868700001901887856012201906       2014                        eng d  a0360-544200aImpact of experimental pressure and temperature on semiclathrate hydrate formation for pre-combustion capture of CO2 using tetra-n-butyl ammonium nitrate0 aImpact of experimental pressure and temperature on semiclathrate  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcDEC  a458-4640 v783 a<p>TBANO(3) (tetra-n-butyl ammonium nitrate) is a promising liquid phase promoter for capturing CO2 via HBGS (hydrate based gas separation) technology. In this study, the impact of experimental pressure and temperature on formation of mixed CO2-H-2-TBANO(3) semiclathrate hydrate for the optimum 1.0 mol% TBANO(3) reported by Babu et al. [1] was investigated. Experimental pressures of 3.0, 4.5 and 6.0 MPa and temperatures of 274.2, 276.2 and 278.2 K were employed. Irrespective of the experimental pressure, shorter induction time was observed for experiments conducted at 274.2 K when compared to the experiments at other temperatures. At a given pressure, the total gas uptake increased with increase in experimental temperature. Similarly at a given temperature, the total gas uptake increases with an increase in pressure. Higher rate of hydrate formation was observed at experimental pressure of 6.0 MPa than at 3.0 and 4.5 MPa irrespective of the experimental temperature. The CO2 composition in hydrate was between 87.5 and 93.2 mol%. Finally, the gas consumption for 1.0 mol% TBANO(3) as promoter was much higher than other promoters of quaternary salts like tetra-n-butyl ammonium bromide and tetra-n-butyl ammonium fluoride at comparable concentration and driving force. (C) 2014 Elsevier Ltd. All rights reserved.</p>10aCarbon dioxide capture10aClathrate process10aGas hydrates10aSemi-clathrates1 aBabu, Ponnivalavan1 aDatta, Stuti1 aKumar, Rajnish1 aLinga, Praveen  uhttps://library.ncl.res.in/content/impact-experimental-pressure-and-temperature-semiclathrate-hydrate-formation-pre-002006nas a2200181   4500008004100000022001400041245012600055210006900181260007100250300001400321490000700335520127600342100001901618700001901637700001901656700001901675856013001694       2014                        eng d  a0888-588500aImpact of fly ash impurity on the hydrate-based gas separation process for carbon dioxide capture from a flue gas mixture0 aImpact of fly ash impurity on the hydratebased gas separation pr  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJUN  a9849-98590 v533 a<p>The hydrate-based gas separation (HBGS) process for gas mixtures of CO2 + N-2 (flue gas) and CO2 + H-2 (fuel gas) has proven to be very efficient and highly selective for CO2 capture. In addition to CO2 and N-2, flue gas from coal-based thermal power stations can contain impurities such as nitrogen oxides (NOx), sulfur oxides (SOx), and fly ash. In this work, the impact of fly ash on the HBGS process efficiency was investigated. Tetrahydrofuran (THF, 1 mol %) was used as a thermodynamic promoter, and sodium dodecyl sulfate (SDS) and sodium dodecyl benzenesulfonate (SDBS) (anionic surfactants) were used as kinetic promoters. Whereas the use of THF in the HBGS process reduces the operating pressure significantly, both SDS and SDBS were found to enhance the rate of hydrate formation. It was observed that the hydrate equilibrium conditions did not change in the presence of fly ash. However, the presence of fly ash enhanced the separation efficiency of the HBGS process by reducing the induction time and increasing the kinetics of hydrate formation. Therefore, the presence of fly ash in a flue gas mixture is not detrimental to the HBGS process, which is a positive factor for the capture and geological sequestration of CO2 in the form of gas hydrates.</p>1 aKumar, Asheesh1 aSakpal, Tushar1 aLinga, Praveen1 aKumar, Rajnish  uhttps://library.ncl.res.in/content/impact-fly-ash-impurity-hydrate-based-gas-separation-process-carbon-dioxide-capture-flue-002022nas a2200313   4500008004100000022001400041245012300055210006900178260009900247300001400346490000700360520092100367653002701288653002201315653001701337653001901354653001401373653003501387100002301422700002001445700001901465700001901484700001201503700001601515700001701531700001701548700001101565856013201576       2014                        eng d  a1876-610200aImpact of pressure and temperature on tetra-n-butyl ammonium bromide semi-clathrate process for carbon dioxide capture0 aImpact of pressure and temperature on tetranbutyl ammonium bromi  aSara Burgerhartstraat 25, Po Box 211, 1000 AE Amsterdam, NetherlandsbElsevier Science BVcMAY  a1780-17830 v613 a<p>The pre-combustion capture of CO2 in an IGCC power plant employing the hydrate based gas separation (HBGS) process is a novel method currently receiving attention around the world. Tetra-n-butyl ammonium bromide (TBAB) is a promoter that has been shown to improve the efficiency of hydrate formation. In this study, the effect of temperature and pressure on 0.3 mol% TBAB solution is investigated. The induction time for the experiments conducted at 6.0 MPa and 274.8 K was found to be lower, while nucleation became increasingly random as temperature is increased and pressure is reduced. Total gas uptake and normalized rate of hydrate formation (NR5) is also the highest for the experiments conducted at 6.0 MPa and 274.8 K. However, it was found that the hydrate phase CO2 composition remains relatively constant at both reduced temperatures and pressures. (C) 2014 The Authors. Published by Elsevier Ltd.</p>10aCarbon dioxide capture10aClathrate process10aGas hydrates10aGas separation10aPromoters10atetra-n-butyl ammonium bromide1 aBabu, Ponnivalavan1 aChin, Weng, Inn1 aKumar, Rajnish1 aLinga, Praveen1 aYan, J.1 aLee, D., J.1 aChou, S., K.1 aDesideri, U.1 aLi, H.  uhttps://library.ncl.res.in/content/impact-pressure-and-temperature-tetra-n-butyl-ammonium-bromide-semi-clathrate-process-carbon01990nas a2200181   4500008004100000022001400041245012600055210006900181260007100250300001400321490000700335520125300342100002301595700002001618700001901638700001901657856013201676       2014                        eng d  a0888-588500aSystematic evaluation of tetra-n-butyl ammonium bromide (TBAB) for carbon dioxide capture employing the clathrate process0 aSystematic evaluation of tetranbutyl ammonium bromide TBAB for c  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR  a4878-48870 v533 a<p>Hydrate based gas separation (HBGS) process for the precombustion capture of CO2 from a fuel gas mixture is a novel method being investigated among the carbon capture and sequestration techniques to reduce CO2 emissions. The efficiency of the HGBS process can be improved by using promoters that reduce the formation pressure of mixed gas hydrates. In this study the effect of tetra-n-butyl ammonium bromide (TBAB) was systematically investigated at a constant temperature of 279.2 K and pressure of 6.0 MPa for different TBAB concentrations of 0.3, 1.0, 1.5, 2.0, and 3.0 mol %, respectively. The 0.3 mol % solutions had a relatively longer average induction time of 20.1 min but exhibited the highest total normalized gas uptake of 0.0104 (+/- 0.0004) mol of gas/mol of water and highest separation factor of 41.51 (+/- 6.391). On the other hand, the 1.0 mol % solution had very short average induction time (&lt;0.5 min) and it had the highest hydrate growth rate of 60.8 (+/- 9.89) mol of gas. min(-1).m(-3), with the separation factor of 13.78 (+/- 3.30). Gas solubility measurements and microscopic images of the hydrate formation were also presented to provide greater insights into the effect of TBAB concentration on the gas uptake.</p>1 aBabu, Ponnivalavan1 aChin, Weng, Inn1 aKumar, Rajnish1 aLinga, Praveen  uhttps://library.ncl.res.in/content/systematic-evaluation-tetra-n-butyl-ammonium-bromide-tbab-carbon-dioxide-capture-employing-002059nas a2200193   4500008004100000022001400041245017900055210006900234260007100303300001400374490000700388520124600395100002301641700001901664700001701683700001901700700001901719856012701738       2014                        eng d  a0013-936X00aThermodynamic and kinetic verification of tetra-n-butyl ammonium nitrate (TBANO(3)) as a promoter for the clathrate process applicable to precombustion carbon dioxide capture0 aThermodynamic and kinetic verification of tetranbutyl ammonium n  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcMAR  a3550-35580 v483 a<p>In this study, tetra-n-butyl ammonium nitrate (TBANO(3)) is evaluated as a promoter for precombustion capture of CO2 via hydrate formation. New hydrate phase equilibrium data for fuel gas (CO2/H-2) mixture in presence of TBANO(3) of various concentrations of 0.5, 1.0, 2.0, 3.0, and 3.7 mol % was determined and presented. Heat of hydrate dissociation was calculated using Clausius-Clapeyron equation and as the concentration of TBANO(3) increases, the heat of hydrate dissociation also increases. Kinetic performance of TBANO(3) as a promoter at different concentrations was evaluated at 6.0 MPa and 274.2 K. Based on induction time, gas uptake, separation factor, hydrate phase CO2 composition, and rate of hydrate growth, 1.0 mol % TBANO(3) solution was found to be the optimum concentration at the experimental conditions of 6.0 MPa and 274.2 K for gas hydrate formation. A 93.0 mol % CO2 rich stream can be produced with a gas uptake of 0.0132 mol of gas/mol of water after one stage of hydrate formation in the presence of 1.0 mol % TBANO(3) solution. Solubility measurements and microscopic images of kinetic measurements provide further insights to understand the reason for 1.0 mol % TBANO(3) to be the optimum concentration.</p>1 aBabu, Ponnivalavan1 aYao, Minghuang1 aDatta, Stuti1 aKumar, Rajnish1 aLinga, Praveen  uhttps://library.ncl.res.in/content/thermodynamic-and-kinetic-verification-tetra-n-butyl-ammonium-nitrate-tbano3-promoter-002012nas a2200229   4500008004100000022001400041245016100055210006900216260010600285300001200391490000800403520106200411653002701473653001701500653002201517653001701539653004301556100002301599700001901622700001901641856012201660       2014                        eng d  a0009-250900aUnusual behavior of propane as a co-guest during hydrate formation in silica sand: potential application to seawater desalination and carbon dioxide capture0 aUnusual behavior of propane as a coguest during hydrate formatio  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcSEP  a342-3510 v1173 a<p>We report an unusual behavior of hydrate formation in silica sand with gas mixtures containing propane as a co-guest. Based on morphology study we observed that propane as a co-guest has the ability to draw water dispersed in silica sand to the hydrate formation region and showed a tendency to result in drastic hydrate growth due to the migration of water molecules to the gas phase region. Hydrate nucleation occurred in the interstitial pore space between the silica sand particles and hydrate growth occurred in the gas phase above the silica sand bed and to sustain the hydrate growth, dispersed water was drawn towards the hydrate growth front. In addition, we elucidated the effect of sand bed height to maximize the growth rates utilizing this behavior that results in enhanced kinetics. We propose conceptual designs for utilizing this behavior of propane as a co-guest in sand for seawater desalination and an innovative approach to simultaneously capture carbon dioxide and desalinate seawater. (C) 2014 Elsevier Ltd. All rights reserved.</p>10aCarbon dioxide capture10aDesalination10aEnhanced kinetics10aGas hydrates10aPropane hydrate: pre-combusuon capture1 aBabu, Ponnivalavan1 aKumar, Rajnish1 aLinga, Praveen  uhttps://library.ncl.res.in/content/unusual-behavior-propane-co-guest-during-hydrate-formation-silica-sand-potential-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-packing01880nas a2200253   4500008004100000022001400041245010400055210006900159260010600228300001200334490000700346520093600353653002701289653002201316653001701338653001901355653001601374653002701390100002301417700001901440700001901459700002001478856012801498       2015                        eng d  a0360-544200aReview of the hydrate based gas separation (HBGS) process for carbon dioxide pre-combustion capture0 aReview of the hydrate based gas separation HBGS process for carb  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcJUN  a261-2790 v853 a<p>In this work, a systematic review of the literature work done so far on the use of hydrate crystallization as a basis to develop data for the hydrate based gas separation (HBGS) process for the capture of CO2 from fuel gas mixtures is presented. Such a gas mixture may arise in integrated gasification combined cycle (IGCC) power plants. A thorough assessment of the thermodynamic, kinetic factors and economic aspects of the HBGS process and critical comments are presented. Compared with competing technologies, high CO2 capacity and the use of water as a solvent are key advantages for the HBGS process for CO2 capture. Furthermore, in this review, a snapshot of the current state-of-the-art is presented and further research and development opportunities and pathways for commercializing the HBGS process for pre-combustion capture of CO2 from IGCC power plants are discussed. (C) 2015 Elsevier Ltd. All rights reserved.</p>10aCarbon dioxide capture10aClathrate process10aGas hydrates10aGas separation10aIGCC plants10aPre-combustion capture1 aBabu, Ponnivalavan1 aLinga, Praveen1 aKumar, Rajnish1 aEnglezos, Peter  uhttps://library.ncl.res.in/content/review-hydrate-based-gas-separation-hbgs-process-carbon-dioxide-pre-combustion-capture-001808nas 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-hydrate02289nas a2200289   4500008004100000022001400041245009800055210006900153260006900222300001200291490000800303520126100311653001901572653002201591653001701613653002401630653002001654653002701674100002901701700002601730700002301756700001901779700002601798700002601824700001901850856013001869       2016                        eng d  a1385-894700aRapid methane hydrate formation to develop a cost effective large scale energy storage system0 aRapid methane hydrate formation to develop a cost effective larg  aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcAPR  a161-1730 v2903 a<p>Natural gas (NG) is the cleanest burning fossil fuel and its usage can significantly reduce CO2 emissions from power plants. With its widespread use, there is an ever increasing need to develop technologies to store NG on a large scale. NG storage via clathrate hydrates is the best option for a large scale storage system because of its non-explosive nature, mild storage conditions, high volumetric capacity and being an environmentally benign process. In this work, we demonstrate a new method to achieve rapid methane hydrate formation in an unstirred tank reactor configuration (UTR) at moderate temperature and pressure conditions employing tetrahydrofuran (THF) as a promoter. For the first time, THF is reported to act both as a thermodynamic and an excellent kinetic promoter for methane hydrate formation. We demonstrate a multi-scale experimental validation of our method to a volumetric sample scale-up factor of 120 and internal reactor diameter scale-up factor of 10. Further, new insights on the dissociation behavior of the hydrates are reported. There is a competitive edge for storing NG via clathrate hydrates compared to compressed natural gas storage both in terms of cost and safety. (C) 2016 Elsevier B.V. All rights reserved.</p>10aEnergy storage10aEnhanced kinetics10aGas hydrates10aNatural gas storage10aTetrahydrofuran10aUnstirred tank reactor1 aVeluswamy, Hari, Prakash1 aWong, Alison, Jia Hui1 aBabu, Ponnivalavan1 aKumar, Rajnish1 aKulprathipanja, Santi1 aRangsunvigit, Pramoch1 aLinga, Praveen  uhttps://library.ncl.res.in/content/rapid-methane-hydrate-formation-develop-cost-effective-large-scale-energy-storage-system-0