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Wei-yi LIU, Yong CHEN, Miao WANG, Han-jing ZHANG. Research Progress on the Effect of Salts on the Stability of Methane Hydrate[J]. Rock and Mineral Analysis, 2018, 37(2): 111-120. doi: 10.15898/j.cnki.11-2131/td.201706110098
Citation: Wei-yi LIU, Yong CHEN, Miao WANG, Han-jing ZHANG. Research Progress on the Effect of Salts on the Stability of Methane Hydrate[J]. Rock and Mineral Analysis, 2018, 37(2): 111-120. doi: 10.15898/j.cnki.11-2131/td.201706110098
shu

Research Progress on the Effect of Salts on the Stability of Methane Hydrate

  • 1.

    School of Geosciences, China University of Petroleum, Qingdao 266580, China

  • 2.

    Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China

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Received Date:  11 June 2017
Revised Date:  09 February 2018
Accepted Date:  21 March 2018
    Abstract
  • The thickness of the methane hydrate stable zone is mainly controlled by the stability of methane hydrate. The temperature, pressure, pore water salinity, and gas component affect the thickness of the hydrate stable zone. The formation of methane hydrate is closely related to the formation of water. Various salt ions in formation water (Cl-, Na+, Mg2+, SO42-, Ca2+, and transition metals Fe, Mn, Cu, Co, Ni) can affect the formation and decomposition conditions of natural gas hydrate. Therefore, studying the effect of salts on the stability of methane hydrates is helpful to better understand the reservoir-forming conditions of methane hydrate. The effects of chloride, sulfate and carbonate on the stability of methane hydrate are evaluated in this paper. With the increase of salinity, the phase equilibrium curve of methane hydrate migrates to low temperature and high pressure under the same salinity condition. The inhibitory effects of different salts and anion and cation on methane hydrate are summarized. Under conditions of the same concentration and different types of salts, when the concentration of salt ranges from 1 to 1.5 mol/L, the inhibition effect of salt on methane hydrate is MgCl2 > CaCl2 > NaCl > KCl. When the concentration of salt is larger than 1.5 mol/L, the inhibitory effect of CaCl2 on methane hydrate is stronger. The inhibitory effect of anions on methane hydrate is controversial, and the inhibitory effect of Mg2+ on methane hydrate is the strongest. From available research results, there is still a gap between the existing data and the actual geological conditions. It is necessary to strengthen the detailed study on chloride-sulfate-carbonate-methane-water systems under actual experimental conditions. It is proposed that the combination of the high-voltage visual reaction chamber with Micro Laser Raman Spectroscopy is likely to accurately obtain the stable temperature and pressure conditions of gas hydrate formation, clarify the inhibitory effect of cations and anions, and understand how salts and ion affect the formation of hydrate and its stability, which will provide reference for the future exploration and development of hydrate.
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    • References
  • [1] Sloan Jr E D, Koh C.Clathrate Hydrates of Natural Gases (The Third Edition)[M].New York:CRC Press, 2007:1-2.

    Google Scholar

    [2] Udachin K A, Ripmeester J A.A complex clathrate hydrate structure showing bimodal guest hydration[J].Nature, 1999, 397:420-423. doi: 10.1038/17097

    CrossRef Google Scholar

    [3] Sloan Jr E D, Koh C.Clathrate Hydrates of Natural Gases (The Second Edition)[M].New York:CRC Press, 1998:223-224.

    Google Scholar

    [4] Kvenvolden K A, Lorenson T D.The global occurrence of natural gas hydrates[J].American Geophysical Union, 2001, 124:3-18.

    Google Scholar

    [5] Milkov A V.Global estimates of hydrate-bound gas in marine sediments:How much is really out there?[J].Earth-Science Reviews, 2004, 66(3):183-197.

    Google Scholar

    [6] Song Y, Yang L, Zhao J, et al.The status of natural gas hydrate research in China:A review[J].Renewable and Sustainable Energy Reviews, 2014, 31:778-791. doi: 10.1016/j.rser.2013.12.025

    CrossRef Google Scholar

    [7] 何勇, 苏正, 吴能友.海底天然气水合物稳定带厚度的影响因素[J].海洋地质前沿, 2012, 28(5):43-47.

    Google Scholar

    He Y, Su Z, Wu N Y.Factors influencing the thickness of gas hydrate stability zone in marine sediments[J].Marine Geology Frontiers, 2012, 28(5):43-47.

    Google Scholar

    [8] Sun C Y, Li W Z, Yang X, et al.Progress in research of gas hydrate[J].Chinese Journal of Chemical Engineering, 2011, 19(1):151-162. doi: 10.1016/S1004-9541(09)60192-0

    CrossRef Google Scholar

    [9] 宋海斌, 耿建华, Wang How-Kin, 等.南海北部东沙海域天然气水合物的初步研究[J].地球物理学报, 2001, 44(5):687-695.

    Google Scholar

    Song H B, Geng J H, Wang H K, et al.A preliminary study of gas hydrates in Dongsha region north of South China Sea[J].Chinese Journal of Geophysics, 2001, 44(5):687-695.

    Google Scholar

    [10] Lu S M.A global survey of gas hydrate development and reserves:Specifically in the marine field[J].Renewable and Sustainable Energy Reviews, 2015, 41(C):884-900.

    Google Scholar

    [11] Nisbet E G, Piper D J W.Giant submarine landslides[J].Nature, 1998, 392(6674):329-330. doi: 10.1038/32765

    CrossRef Google Scholar

    [12] Bains S, Corfield R M, Norris R D.Mechanisms of climate warming at the end of the Paleocene[J].Science, 1999, 285(5428):724-727. doi: 10.1126/science.285.5428.724

    CrossRef Google Scholar

    [13] Matsumoto R, Uchida T, Waseda A, et al. Occurrence, Structure and Composition of Natural Gas Hydrate Recovered from the Blake Ridge, Northwest Atlantic[R]. Proceedings of Ocean Drill Program Science Results, 2000: 13-28.https://www.sciencedirect.com/science/article/pii/S0025322707001387

    Google Scholar

    [14] Kvenvolden K A, Lorenson T D. The Global Occurrence of Natural Gas Hydrate[R]//Natural Gas Hydrates: Occurrence, Distribution, and Detection[J]. 2001: 3-18.http://onlinelibrary.wiley.com/book/10.1029/GM124

    Google Scholar

    [15] 金春爽, 汪集旸, 张光学.南海天然气水合物稳定带的影响因素[J].矿床地质, 2005, 24(4):388-397.

    Google Scholar

    Jin C S, Wang J Y, Zhang G X.Factors affecting natural gas hydrate stability zone in the South China Sea[J].Mineral Deposits, 2005, 24(4):388-397.

    Google Scholar

    [16] 王宏斌, 梁劲, 龚跃华, 等.基于天然气水合物地震数据计算南海北部陆坡海底热流[J].现代地质, 2005, 19(1):67-73.

    Google Scholar

    Wang H B, Liang J, Gong Y H, et al.Estimation of the heat flow in the northern of the South China Sea based on the seismic data of gas hydrate[J].Geoscience, 2005, 19(1):67-73.

    Google Scholar

    [17] 张金华, 魏伟, 张吝文.海底天然气水合物相平衡及稳定带的影响分析[J].化学工程与装备, 2011(1):39-42.

    Google Scholar

    Zhang J H, Wei W, Zhang L W.Analysis of phase equilibrium and stability zone of gas hydrate in submarine[J].Chemical Engineering & Equipment, 2011(1):39-42.

    Google Scholar

    [18] Booth J S, Winters W J, Dillon W P, et al.Major Occurrences and Reservoir Concepts of Marine Clathrate Hydrates:Implications of Field Evidence[M].London:Woods Hole Coastal and Marine Science Center, 1998:113-127.

    Google Scholar

    [19] 许威, 邱楠生, 孙长宇, 等.不同因素对天然气水合物稳定带厚度的影响[J].天然气地球科学, 2010, 21(3):528-534.

    Google Scholar

    Xu W, Qiu N S, Sun C Y, et al.Different factors on the thickness of gas hydrate stability zone[J].Natural Gas Geoscience, 2010, 21(3):528-534.

    Google Scholar

    [20] Milkov A V, Sassen R.Thickness of the gas hydrate stability zone, Gulf of Mexico continental slope[J].Marine and Petroleum Geology, 2000, 17(9):981-991. doi: 10.1016/S0264-8172(00)00051-9

    CrossRef Google Scholar

    [21] Milkov A V, Sassen R.Economic geology of offshore gas hydrate accumulations and provinces[J].Marine & Petroleum Geology, 2002, 19(1):1-11.

    Google Scholar

    [22] 杨顶辉, Xu Wenyue.盐度对甲烷气水合物系统的影响[J].中国科学(D辑), 2007, 37(10):1370-1381.

    Google Scholar

    Yang D H, Xu W Y.Effects of salinity on methane hydrate system[J].Scientia Sinica (Terrae), 2007, 37(10):1370-1381.

    Google Scholar

    [23] Handa Y P.Effect of hydrostatic pressure and salinity on the stability of gas hydrates[J].Journal of Physical Chemistry, 1990, 94:2652-2657. doi: 10.1021/j100369a077

    CrossRef Google Scholar

    [24] Sylva T Y, Kinoshita C K, Masutani S M.Inhibiting effects of transition metal salts on methane hydrate stability[J].Chemical Engineering Science, 2016, 155:10-15. doi: 10.1016/j.ces.2016.06.028

    CrossRef Google Scholar

    [25] Sun S C, Kong Y Y, Zhang Y, et al.Phase equilibrium of methane hydrate in silica sand containing chloride salt solution[J].The Journal of Chemical Thermodynamics, 2015, 90:116-121. doi: 10.1016/j.jct.2015.06.030

    CrossRef Google Scholar

    [26] Villard M.Sur les hydrates de méthane et d'éthylène[J].Comptes Rendus, 1888, 107:257.

    Google Scholar

    [27] Deaton W M, Frost Jr E M. Gas Hydrates and Their Relation to the Operation of Natural-gas Pipe Lines[R]. Bureau of Mines, Amarillo, TX (USA): Helium Research Center, 1946.

    Google Scholar

    [28] de Roo J L, Peters C J, Lichtenthaler R N, et al.Occurrence of methane hydrate in saturated and unsaturated solutions of sodium chloride and water in dependence of temperature and pressure[J].AIChE Journal, 1983, 29(4):651-657. doi: 10.1002/(ISSN)1547-5905

    CrossRef Google Scholar

    [29] Millero F J, Feistel R, Wright D G, et al.The com-position of standard seawater and the definition of the reference-composition salinity scale[J].Deep Sea Research Part Ⅰ:Oceanographic Research Papers, 2008, 55(1):50-72. doi: 10.1016/j.dsr.2007.10.001

    CrossRef Google Scholar

    [30] Aparicio-González A, Duarte C M, Tovar-Sánchez A.Trace metals in deep ocean waters:A review[J].Journal of Marine Systems, 2012, 100:26-33.

    Google Scholar

    [31] Ross M J, Toczylkin L S.Hydrate dissociation pressures for methane or ethane in the presence of aqueous solutions of triethylene glycol[J].Journal of Chemical and Engineering Data, 1992, 37(4):488-491. doi: 10.1021/je00008a026

    CrossRef Google Scholar

    [32] Kang S P, Chun M K, Lee H.Phase equilibria of methane and carbon dioxide hydrates in the aqueous MgCl2 solutions[J].Fluid Phase Equilibria, 1998, 147(1):229-238.

    Google Scholar

    [33] Jager M D, Sloan E D.The effect of pressure on methane hydration in pure water and sodium chloride solutions[J].Fluid Phase Equilibria, 2001, 185(1):89-99.

    Google Scholar

    [34] van der Waals J H, Platteeuw J C. Clathrate Solutions[M]//Prigogine Ⅰ: Advances in Chemical Physics Ⅱ. New York, 1959.

    Google Scholar

    [35] Duan Z, Li D, Chen Y, et al.The influence of temper-ature, pressure, salinity and capillary force on the formation of methane hydrate[J].Geoscience Frontiers, 2011, 2(2):125-135. doi: 10.1016/j.gsf.2011.03.009

    CrossRef Google Scholar

    [36] Tishchenko P, Hensen C, Wallmann K, et al.Calculation of the stability and solubility of methane hydrate in seawater[J].Chemical Geology, 2005, 219(1):37-52.

    Google Scholar

    [37] Chin H Y, Lee B S, Chen Y P, et al.Prediction of phase equilibrium of methane hydrates in the presence of ionic liquids[J].Industrial & Engineering Chemistry Research, 2013, 52(47):16985-16992.

    Google Scholar

    [38] Parrish W R, Prausnitz J M.Dissociation pressures of gas hydrates formed by gas mixtures[J].Industrial & Engineering Chemistry Process Design and Development, 1972, 11(1):26-35.

    Google Scholar

    [39] Rashid S, Fayazi A, Harimi B, et al.Evolving a robust approach for accurate prediction of methane hydrate formation temperature in the presence of salt inhibitor[J].Journal of Natural Gas Science & Engineering, 2014, 18(2):194-204.

    Google Scholar

    [40] Ng H J, Robinson D B.Hydrate formation in systems containing methane, ethane, propane, carbon dioxide or hydrogen sulfide in the presence of methanol[J].Fluid Phase Equilibria, 1985, 21(1-2):145-155. doi: 10.1016/0378-3812(85)90065-2

    CrossRef Google Scholar

    [41] Lee S Y, Holder G D.Model for gas hydrate equilibria using a variable reference chemical potential:Part 1[J].AIChE Journal, 2002, 48(1):161-167. doi: 10.1002/(ISSN)1547-5905

    CrossRef Google Scholar

    [42] Englezos P, Bishnoi P R.Prediction of gas hydrate formation conditions in aqueous electrolyte solutions[J].AIChE Journal, 1988, 34(10):1718-1721. doi: 10.1002/(ISSN)1547-5905

    CrossRef Google Scholar

    [43] Shabani M M, Rashtchian D, Ghotbi C, et al.Prediction of hydrate formation for the systems containing single and mixed electrolyte solutions[J].Iranian Journal of Chemistry and Chemical Engineering, 2007, 26(1):35-45.

    Google Scholar

    [44] Javanmardi J, Moshfeghian M, Maddox R N.Simple method for predicting gas-hydrate-forming conditions in aqueous mixed-electrolyte solutions[J].Energy & Fuels, 1998, 12(2):219-222.

    Google Scholar

    [45] Javanmardi J, Moshfeghian M.A new approach for prediction of gas hydrate formation conditions in aqueous electrolyte solutions[J].Fluid Phase Equilibria, 2000, 168(2):135-148. doi: 10.1016/S0378-3812(99)00322-2

    CrossRef Google Scholar

    [46] 孙长宇, 黄强, 陈光进.气体水合物形成的热力学与动力学研究进展[J].化工学报, 2006, 57(5):1031-1039.

    Google Scholar

    Sun C Y, Huang Q, Chen G J.Progress of thermodynamics and kinetics of gas hydrate formation[J].Journal of Chemical Industry and Engineering (China), 2006, 57(5):1031-1039.

    Google Scholar

    [47] Palermo T, Arla D, Borregales M, et al. Study of the Agglomeration between Hydrate Particles in Oil Using Differential Scanning Calorimetry (DSC)[C]//Proceedings of the Fifth International Conference on Gas Hydrates. 2005: 12-16.https://www.sciencedirect.com/science/article/pii/S0009250908003539

    Google Scholar

    [48] Dalmazzone D, Hamed N, Dalmazzone C.DSC measure-ments and modelling of the kinetics of methane hydrate formation in water-in-oil emulsion[J].Chemical Engineering Science, 2009, 64(9):2020-2026. doi: 10.1016/j.ces.2009.01.028

    CrossRef Google Scholar

    [49] Thatai S, Khurana P, Prasad S, et al.Plasmonic detection of Cd2+ ions using surface-enhanced Raman scattering active core-shell nanocomposite[J].Talanta, 2015, 134:568-575. doi: 10.1016/j.talanta.2014.11.024

    CrossRef Google Scholar

    [50] Bonales L J, Muñoz-Iglesias V, Santamaría-Pérez D, et al.Quantitative Raman spectroscopy as a tool to study the kinetics and formation mechanism of carbonates[J].Spectrochimica Acta Part A:Molecular and Biomolecular Spectroscopy, 2013, 116:26-30. doi: 10.1016/j.saa.2013.06.121

    CrossRef Google Scholar

    [51] Sum A K, Burruss R C, Sloan E D.Measurement of clathrate hydrates via Raman spectroscopy[J].The Journal of Physical Chemistry B, 1997, 101(38):7371-7377. doi: 10.1021/jp970768e

    CrossRef Google Scholar

    [52] Subramanian S, Sloan Jr E D.Molecular measurements of methane hydrate formation[J].Fluid Phase Equilibria, 1999, 158-160:813-820. doi: 10.1016/S0378-3812(99)00134-X

    CrossRef Google Scholar

    [53] Chazallon B, Focsa C, Charlou J L, et al.A comparative Raman spectroscopic study of natural gas hydrates collected at different geological sites[J].Chemical Geology, 2007, 244(1):175-185.

    Google Scholar

    [54] Uchida A, Jagendorf A T, Hibino T, et al.Effects of hydrogen peroxide and nitric oxide on both salt and heat stress tolerance in rice[J].Plant Science, 2002, 163(3):515-523. doi: 10.1016/S0168-9452(02)00159-0

    CrossRef Google Scholar

    [55] 陈勇, 周瑶琪.天然流体包裹体中甲烷水合物生成条件原位变温拉曼光谱研究[J].光谱学与光谱分析, 2007, 27(8):1547-1550.

    Google Scholar

    Chen Y, Zhou Y Q.In situ temperature-dependent Raman spectroscopic on methane hydrate formation in natural fluid inclusion[J].Spectroscopy and Spectral Analysis, 2007, 27(8):1547-1550.

    Google Scholar

    [56] 吕万军, I-Ming Chou, Robert C.Burruss, 等.拉曼光谱原位观测水合物形成后的饱和甲烷浓度[J].地球化学, 2005, 34(2):187-192.

    Google Scholar

    Lü W J, Chou I M, Burruss R C, et al.In situ observation of variation of methane concentration in water during the growth of hydrate using Raman spectroscopy[J].Geochemica, 2005, 34(2):187-192.

    Google Scholar

    [57] Hesse R.Pore-water anomalies in gas hydrate-bearing sediments of the deeper continental margins:Facts and problems[J].Journal of Inclusion Phenomena and Macrocyclic Chemistry, 1990, 8(1):117-138.

    Google Scholar

    [58] 马燕. 盐溶液体系中天然气水合物稳定性的研究[D]. 淄博: 山东理工大学, 2011.

    Google Scholar

    Ma Y. Study on the Stability of Natural Gas Hydrates in the Salt Solution System[D]. Zibo: Shandong University of Technology, 2011.

    Google Scholar

    [59] Maekawa T.Equilibrium conditions for gas hydrates of methane and ethane mixtures in pure water and sodium chloride solution[J].Geochemical Journal, 2001, 35(1):59-66. doi: 10.2343/geochemj.35.59

    CrossRef Google Scholar

    [60] Lu H, Matsumoto R.Experimental studies on the possible influences of composition changes of pore water on the stability conditions of methane hydrate in marine sediments[J].Marine Chemistry, 2005, 93(2):149-157.

    Google Scholar

    [61] Kharrat M, Dalmazzone D.Experimental determination of stability conditions of methane hydrate in aqueous calcium chloride solutions using high pressure differential scanning calorimetry[J].The Journal of Chemical Thermodynamics, 2003, 35(9):1489-1505. doi: 10.1016/S0021-9614(03)00121-6

    CrossRef Google Scholar

    [62] Atik Z, Windmeier C, Oellrich L R.Experimental gas hydrate dissociation pressures for pure methane in aqueous solutions of MgCl2 and CaCl2 and for a (methane+ethane) gas mixture in an aqueous solution of (NaCl+MgCl2)[J].Journal of Chemical & Engineering Data, 2006, 51(5):1862-1867.

    Google Scholar

    [63] Mohammadi A H, Afzal W, Richon D.Gas hydrates of methane, ethane, propane, and carbon dioxide in the presence of single NaCl, KCl, and CaCl2 aqueous solutions:Experimental measurements and predictions of dissociation conditions[J].The Journal of Chemical Thermodynamics, 2008, 40(12):1693-1697. doi: 10.1016/j.jct.2008.06.015

    CrossRef Google Scholar

    [64] Mohammadi A H, Kraouti I, Richon D.Methane hydrate phase equilibrium in the presence of NaBr, KBr, CaBr2, K2CO3, and MgCl2 aqueous solutions:Experimental measurements and predictions of dissociation conditions[J].The Journal of Chemical Thermodynamics, 2009, 41(6):779-782. doi: 10.1016/j.jct.2009.01.004

    CrossRef Google Scholar

    [65] Lu H, Matsumoto R, Tsuji Y, et al.Anion plays a more important role than cation in affecting gas hydrate stability in electrolyte solution?-A recognition from experimental results[J].Fluid Phase Equilibria, 2001, 178(1):225-232.

    Google Scholar

    [66] 宋永臣, 杨明军, 刘瑜, 等.离子对甲烷水合物相平衡的影响[J].化工学报, 2009(6):1362-1366.

    Google Scholar

    Song Y C, Yang M J, Liu Y, et al.Influence of ions on phase equilibrium of methane hydrate[J].Journal of Chemical Industry and Engineering, 2009(6):1362-1366.

    Google Scholar

    [67] Berecz E, Balla-Achs M.Gas Hydrates[M].New York:Elsevier Science Publishing Company, 1983.

    Google Scholar

    [68] Liu C L, Ye Y G, Sun S C, et al.Experimental studies on the P-T stability conditions and influencing factors of gas hydrate in different systems[J].Science China (Earth Sciences), 2013, 56(4):594-600. doi: 10.1007/s11430-012-4564-3

    CrossRef Google Scholar

    [69] Dholabhai P D, Englezos P, Kalogerakis N, et al.Equilibrium conditions for methane hydrate formation in aqueous mixed electrolyte solutions[J].The Canadian Journal of Chemical Engineering, 1991, 69(3):800-805. doi: 10.1002/cjce.v69:3

    CrossRef Google Scholar

    [70] 刘伟, 金翔龙, 初凤友, 等.海底天然气水合物相平衡的影响因素[J].海洋地质前沿, 2011, 27(5):16-23.

    Google Scholar

    Liu W, Jin X L, Chu F Y, et al.Research on influencing factors of gas hydrate phase equilibrium in marine sediments[J].Marine Geology Frontiers, 2011, 27(5):16-23.

    Google Scholar

    [71] Pieroen A P.Gas hydrates-approximate relations between heat of formation, composition and equilibrium temperature lowering by "inhibitors"[J].Recueil des Travaux Chimiques des Pays-Bas, 1955, 74(8):995-1002.

    Google Scholar

    [72] Dickens G R, Quinby-Hunt M S.Methane hydrate stability in pore water:A simple theoretical approach for geophysical applications[J].Journal of Geophysical Research:Solid Earth, 1997, 102(B1):773-783. doi: 10.1029/96JB02941

    CrossRef Google Scholar

    [73] 黄子卿.电解质溶液理论导论[M].北京:科学出版社, 1983:49-51.

    Google Scholar

    Huang Z Q.Introduction of Theoretical Electrolyte Solution[M].Beijing:Science Press, 1983:49-51.

    Google Scholar

    [74] Sabil K M, Duarte A R C, Zevenbergen J, et al.Kinetic of formation for single carbon dioxide and mixed carbon dioxide and tetrahydrofuran hydrates in water and sodium chloride aqueous solution[J].International Journal of Greenhouse Gas Control, 2010, 4(5):798-805. doi: 10.1016/j.ijggc.2010.05.010

    CrossRef Google Scholar

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