01614nas a2200253   4500008004100000022001400041245006500055210006500120260011000185300001400295490000700309520072400316653003601040653002701076653001301103653002401116653002101140653002101161100001901182700001901201700001901220700001901239856010201258       2012                        eng d  a0376-471000aCarbon dioxide capture using amine functionalized silica gel0 aCarbon dioxide capture using amine functionalized silica gel  aDR K S KRISHNAN MARG, PUSA CAMPUS, NEW DELHI 110 012, INDIAbNATL INST SCIENCE COMMUNICATION-NISCAIRcSEP  a1214-12220 v513 a<p>Commercially available silica gel is chemically modified for carbon dioxide capture. Calcinated silica gel of certain particle size functionalized with amine using two different methods, wet impregnation and grafting via silane chemistry has been employed as a porous media. The prepared material is characterized by Fourier transform infrared, scanning electron microscopy, energy dispersive analysis of X-rays, thermogravimetry and N-2 physisorption techniques. Gas uptake measurements have been carried out to ascertain the CO2 capture capacity of the amine functionalized material. The experiments have been carried out at moderate pressure and temperature range to ascertain its potential for easy scale up.</p>10aAmine functionalized silica gel10aCarbon dioxide capture10agrafting10aPoly(ethyleneimine)10aSilane chemistry10aWet impregnation1 aSakpal, Tushar1 aKumar, Asheesh1 aKamble, Sanjay1 aKumar, Rajnish  uhttps://library.ncl.res.in/content/carbon-dioxide-capture-using-amine-functionalized-silica-gel-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-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-002138nas a2200241   4500008004100000022001400041245009000055210006900145260007100214300001400285490000600299520129500305653001501600653001601615653001501631653002901646653001801675100002601693700001901719700001901738700001901757856012001776       2015                        eng d  a2168-048500aCarbon dioxide sequestration: influence of porous media on hydrate formation kinetics0 aCarbon dioxide sequestration influence of porous media on hydrat  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJUN  a1205-12140 v33 a<p>In the present study, CO, sequestration by hydrate formation in porous sediments has been discussed. Two siliceous materials with high porosities, pumice and fire hardened red clay (FHRC), have been used as packing materials in a fixed bed setup to study hydrate formation kinetics. The results obtained using the aforementioned materials were compared with those obtained using silica sand and quartz. Carbon dioxide hydrate formation kinetics was studied at 3.0 MPa pressure and 274 K temperature. Two different types of experiments were conducted: (a) using a constant volume of water and (b) maintaining a constant bed height. These experiments were conducted using the different porous media individually as packing materials. It was observed that pumice as the porous medium showed better hydrate formation kinetics resulting in 46 mol % water to hydrate conversion in 5 h. Moreover, kinetics was enhanced with decrease in the bed height of pumice; this suggests that at field scale adaptation of CO, sequestration in geological formations, mass transfer limitations would be significant. The effects of particle size on hydrate formation kinetics were also investigated. It was observed that hydrate formation kinetics was enhanced with decrease in the particle size fraction.</p>10aBed height10aGas hydrate10agas uptake10aGeological sequestration10aParticle size1 aBhattacharjee, Gaurav1 aKumar, Asheesh1 aSakpal, Tushar1 aKumar, Rajnish  uhttps://library.ncl.res.in/content/carbon-dioxide-sequestration-influence-porous-media-hydrate-formation-kinetics-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-packing01845nas a2200229   4500008004100000022001400041245011200055210006900167260007700236300001200313490000600325520102600331653001501357653001301372653001501385653001301400653002401413100001901437700001901456700001901475856012101494       2015                        eng d  a2194-428800aInfluence of low-dosage hydrate inhibitors on methane clathrate hydrate formation and dissociation kinetics0 aInfluence of lowdosage hydrate inhibitors on methane clathrate h  aBOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANYbWILEY-V C H VERLAG GMBHcJUL  a717-7250 v33 a<p>This work investigates the effect of low-dosage hydrate inhibitors (LDHIs) on methane hydrate formation and dissociation. The hydrate inhibitors used in this study were the sodium salt of polyacrylic acid, a polysaccharide chitosan, and the linear sulfated polysaccharide i-carrageenan; the inhibiting behavior of these additives were compared with that of the commonly used hydrate inhibitor polyvinylpyrrolidone for methane hydrate formation. A LDHI concentration of 1wt% was found to increase the induction time relative to that at a LDHI concentration of 0.1wt%. Chitosan was found to be better than the others in reducing nucleation and the growth rate of the hydrate at a concentration of 1wt%. At a lower concentration of 0.1wt%, nucleation inhibition was minimal, however, growth inhibition was significant. The effect of these inhibitors on the decomposition rate of the hydrate was also studied, and the decomposition kinetics at a constant driving force in excess of three-phase equilibrium is reported.</p>10agas uptake10ahydrates10ainhibitors10akinetics10athermal stimulation1 aKumar, Asheesh1 aSakpal, Tushar1 aKumar, Rajnish  uhttps://library.ncl.res.in/content/influence-low-dosage-hydrate-inhibitors-methane-clathrate-hydrate-formation-and-001906nas 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<p>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.</p>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-001767nas a2200193   4500008004100000022001400041245009800055210006900153260007100222300001400293490000700307520103400314100001901348700001901367700002601386700001801412700001901430856012401449       2016                        eng d  a0888-588500aImpact of H2S impurity on carbon dioxide hydrate formation kinetics in fixed bed arrangements0 aImpact of H2S impurity on carbon dioxide hydrate formation kinet  a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcJUL  a7964-79720 v553 a<p>In the present work, a combination of silica sand and metallic sheets as a fixed bed media was used for carbon dioxide hydrate formation studies. Two metallic sheets, aluminum and brass, were incorporated into the fixed bed of silica sand to enhance heat transfer properties of the bed. The results obtained from this arrangement of metal sheets were compared with those obtained with a pure silica sand system. Both brass and aluminum systems were found to be good candidates to enhance gas hydrate formation kinetics compared to simply a sand system. Production of fuel gas from coal often contains a toxic gas, hydrogen sulfide (H2S). For the first time, the effect of H2S on the formation kinetics of CO2 + H-2 + H2S hydrates has been studied. It was observed that the presence of H2S does not affect the hydrate formation kinetics and total gas uptake in the presence of H2S is either as good as CO2 + H-2 hydrate or better. However, H2S impurity in the fuel gas mixture shows a corrosive effect on silica sand media.</p>1 aKumar, Asheesh1 aSakpal, Tushar1 aBhattacharjee, Gaurav1 aKumar, Anupam1 aKumar, Rajnish  uhttps://library.ncl.res.in/content/impact-h2s-impurity-carbon-dioxide-hydrate-formation-kinetics-fixed-bed-arrangements