Gas hydrate-caused pipeline plugging is an industrial nuisance for petroleum flow assurance that calls for technological innovations.Traditional thermodynamic inhibitors such as glycols and inorganic salts suffer from...Gas hydrate-caused pipeline plugging is an industrial nuisance for petroleum flow assurance that calls for technological innovations.Traditional thermodynamic inhibitors such as glycols and inorganic salts suffer from high dosing,environmental unfriendliness,corrosiveness,and economical burden.The development and use of kinetic hydrate inhibitors(KHIs),mostly polymeric compounds,with their inhibiting effects on hydrate nucleation and growth are considered an effective and economically viable chemical treatment for hydrate prevention.However,the actual performance of a KHI candidate is dependent on various factors including its chemical structure,molecular weight,spatial configuration,effective concentration,pressure and temperature,evaluation methods,use of other additives,etc.This review provides a short but systematic overview of the fundamentals of natural gas hydrates,the prevailing categories of polymeric kinetic hydrate inhibitors with proposed inhibition mechanisms,and the various synergists studied for boosting the KHI performance.Further research endeavors are in need to unveil the KHI working modes under different conditions.The conjunctive use of KHIs and synergists may facilitate the commercial application of effective KHIs to tackle the hydrate plugging problem in the oil and gas flow assurance practices.展开更多
Natural gas hydrates easily form in pipelines,causing potential safety issues during oil and gas production and transportation.Injecting gas hydrate inhibitors is one of the most effective methods for preventing gas h...Natural gas hydrates easily form in pipelines,causing potential safety issues during oil and gas production and transportation.Injecting gas hydrate inhibitors is one of the most effective methods for preventing gas hydrate formation or aggregation.However,some thermodynamic hydrate inhibitors are toxic and harmful to the environment,whereas degradation of kinetic inhibitors is difficult.Therefore,environmentally friendly and easily biodegradable novel green inhibitors have been proposed and investigated.This paper provides a short but systematic review of the inhibitory performance of amino acids,antifreeze proteins,and ionic liquids.For different hydrate formation systems,the influences of the inhibitor type,structure,and concentration on the inhibitory effects are summarized.The mechanism of green inhibitors as kinetic inhibitors is also discussed.The progress described here will facilitate further developments of such green inhibitors for gas hydrate formation.展开更多
Gas hydrate reserves are potential source of clean energy having low molecular weight hydrocarbons trapped in water cages.In this work,we report how organic compounds of different chain lengths and hydrophilicities wh...Gas hydrate reserves are potential source of clean energy having low molecular weight hydrocarbons trapped in water cages.In this work,we report how organic compounds of different chain lengths and hydrophilicities when used in small concentration may modify hydrate growth and either act as hydrate inhibitors or promoters.Hydrate promoters foster the hydrate growth kinetics and are used in novel applications such as methane storage as solidified natural gas,desalination of sea water and gas separation.On the other hand,gas hydrate inhibitors are used in oil and gas pipelines to alter the rate at which gas hydrate nucleates and grows.Inhibitors such as methanol and ethanol which form strong hydrogen bond with water have been traditionally used as hydrate inhibitors.However,due to relatively high volatility a significant portion of these inhibitors ends up in gas stream and brings further complexity to the safe transportation of natural gas.In this study,organic additives such as oxalic acid,succinic acid and L-aspartic acid(all three)having––COOH group(s)with aspartic acid having an additional––NH2 group,are investigated for gas hydrate promotion/inhibition behavior.These compounds are polar in nature and thus have significant solubility in liquid water;the presence of weak acidic and water loving(carboxylic/amine groups)moieties makes these organic acids an excellent candidate for further study.This study would pave ways to identify a novel(read better)promoter/inhibitor for gas hydrate formation.Suitable thermodynamic conditions were generated in a stirred tank reactor coupled with cooling system;comparison of gas hydrate formation kinetics with and without additives were carried out to identify the effect of these acids on the formation and growth of hydrates.The possible mechanisms by which these additives inhibit or promote the hydrate growth are also discussed.展开更多
The development of environmental friendly low dose hydrate inhibitors like kinetic hydrate inhibitors(KHIs)is of great significance for the flow assurance in oil&gas production and transportation.In this work,a co...The development of environmental friendly low dose hydrate inhibitors like kinetic hydrate inhibitors(KHIs)is of great significance for the flow assurance in oil&gas production and transportation.In this work,a combined molecular dynamic simulation and experimental verification approach was adopted to increase the efficiency of KHIs development.The inhibition effect of a series of copolymers(N-vinylpyrrolidone and N-acrylate)on hydrate growth was studied by using both molecular dynamics simulation and experimental approaches.The simulation results demonstrated that introduction of hydrophobic ester and butyl group in PVP is beneficial for the inhibition.The length of the alkyl chain of ester group played an important role in improving inhibition performance.PVP-A,the one being introduced butyl ester group into PVP gets the best inhibition effect.In addition,inhibitors can restrict methane bubbles to re-dissolve into the liquid phase,thereby inhibiting the growth of methane hydrate.Increasing the interaction between KHIs and methane can also improve the inhibitory effect of KHIs.The experimental results confirm the reliability of the molecular dynamics simulation.展开更多
基金Supported by China Postdoctoral Science Foundation Funded Project(2017M620050)
文摘Gas hydrate-caused pipeline plugging is an industrial nuisance for petroleum flow assurance that calls for technological innovations.Traditional thermodynamic inhibitors such as glycols and inorganic salts suffer from high dosing,environmental unfriendliness,corrosiveness,and economical burden.The development and use of kinetic hydrate inhibitors(KHIs),mostly polymeric compounds,with their inhibiting effects on hydrate nucleation and growth are considered an effective and economically viable chemical treatment for hydrate prevention.However,the actual performance of a KHI candidate is dependent on various factors including its chemical structure,molecular weight,spatial configuration,effective concentration,pressure and temperature,evaluation methods,use of other additives,etc.This review provides a short but systematic overview of the fundamentals of natural gas hydrates,the prevailing categories of polymeric kinetic hydrate inhibitors with proposed inhibition mechanisms,and the various synergists studied for boosting the KHI performance.Further research endeavors are in need to unveil the KHI working modes under different conditions.The conjunctive use of KHIs and synergists may facilitate the commercial application of effective KHIs to tackle the hydrate plugging problem in the oil and gas flow assurance practices.
基金Supported by National Key Research and Development Plan of China(2017YFC0307306)the National Natural Science Foundation of China(51876211)
文摘Natural gas hydrates easily form in pipelines,causing potential safety issues during oil and gas production and transportation.Injecting gas hydrate inhibitors is one of the most effective methods for preventing gas hydrate formation or aggregation.However,some thermodynamic hydrate inhibitors are toxic and harmful to the environment,whereas degradation of kinetic inhibitors is difficult.Therefore,environmentally friendly and easily biodegradable novel green inhibitors have been proposed and investigated.This paper provides a short but systematic review of the inhibitory performance of amino acids,antifreeze proteins,and ionic liquids.For different hydrate formation systems,the influences of the inhibitor type,structure,and concentration on the inhibitory effects are summarized.The mechanism of green inhibitors as kinetic inhibitors is also discussed.The progress described here will facilitate further developments of such green inhibitors for gas hydrate formation.
基金the Department of Science and Technology, Science and Engineering Research Board, India for the project grant EMR/2017/000810the Department of Science and Technology-Science and Engineering Research Board, India for the award of National Postdoctoral Fellowship (Principal Investigator) and project grant DST-SERB-PDF-2017/003075
文摘Gas hydrate reserves are potential source of clean energy having low molecular weight hydrocarbons trapped in water cages.In this work,we report how organic compounds of different chain lengths and hydrophilicities when used in small concentration may modify hydrate growth and either act as hydrate inhibitors or promoters.Hydrate promoters foster the hydrate growth kinetics and are used in novel applications such as methane storage as solidified natural gas,desalination of sea water and gas separation.On the other hand,gas hydrate inhibitors are used in oil and gas pipelines to alter the rate at which gas hydrate nucleates and grows.Inhibitors such as methanol and ethanol which form strong hydrogen bond with water have been traditionally used as hydrate inhibitors.However,due to relatively high volatility a significant portion of these inhibitors ends up in gas stream and brings further complexity to the safe transportation of natural gas.In this study,organic additives such as oxalic acid,succinic acid and L-aspartic acid(all three)having––COOH group(s)with aspartic acid having an additional––NH2 group,are investigated for gas hydrate promotion/inhibition behavior.These compounds are polar in nature and thus have significant solubility in liquid water;the presence of weak acidic and water loving(carboxylic/amine groups)moieties makes these organic acids an excellent candidate for further study.This study would pave ways to identify a novel(read better)promoter/inhibitor for gas hydrate formation.Suitable thermodynamic conditions were generated in a stirred tank reactor coupled with cooling system;comparison of gas hydrate formation kinetics with and without additives were carried out to identify the effect of these acids on the formation and growth of hydrates.The possible mechanisms by which these additives inhibit or promote the hydrate growth are also discussed.
基金received from the the National Natural Science Foundation of China(21776301,U20B6005)。
文摘The development of environmental friendly low dose hydrate inhibitors like kinetic hydrate inhibitors(KHIs)is of great significance for the flow assurance in oil&gas production and transportation.In this work,a combined molecular dynamic simulation and experimental verification approach was adopted to increase the efficiency of KHIs development.The inhibition effect of a series of copolymers(N-vinylpyrrolidone and N-acrylate)on hydrate growth was studied by using both molecular dynamics simulation and experimental approaches.The simulation results demonstrated that introduction of hydrophobic ester and butyl group in PVP is beneficial for the inhibition.The length of the alkyl chain of ester group played an important role in improving inhibition performance.PVP-A,the one being introduced butyl ester group into PVP gets the best inhibition effect.In addition,inhibitors can restrict methane bubbles to re-dissolve into the liquid phase,thereby inhibiting the growth of methane hydrate.Increasing the interaction between KHIs and methane can also improve the inhibitory effect of KHIs.The experimental results confirm the reliability of the molecular dynamics simulation.
