Characteristics study on hydrates formation from gas mixture under ionic liquid together with kinetic hydrate inhibitors

doi:10.11949/0438-1157.20230087

Abstract

Abstract:

To recognize the synergistic inhibition of ionic liquids, the effects of N-butyl-N-methylpyrrolidine tetrafluoroborate ([BMP][BF₄]), two kinetic inhibitors (KHIs) (poly(N-vinylpyrrolidone) (PVP) and poly(N-vinylcaprolactam) (PVCap) ) and binary mixtures of KHI with [BMP][BF₄] on the hydrate formation process from methane/ethane/propane ternary mixture were investigated by using the isothermal isochoric method. By analyzing the time-dependent variation of pressure and gas phase composition, it was found that synthesized natural gas hydrate grew in a two-step way. At a high subcooling degree (>10℃) and stirring rate (1000 r/min), those tested additives failed when used alone, while an enhanced inhibition performance of PVCap was observed with the assistance of [BMP][BF₄]. Both powder X-ray diffraction and laser Raman spectroscopy test results show that the hydrate samples formed in all systems have sⅠ and sⅡ structures at the same time. The addition of inhibitors mainly affects the relative content of the two crystal structures and the cage occupancy of each guest molecule. Finally, a synergistic inhibition mechanism was proposed.

Key words: kinetic hydrate inhibitor, hydrate, ionic liquid, polymer, mechanism

摘要：

利用等温恒容法实验考察了一种高性能离子液体N-丁基-N-甲基吡咯烷四氟硼酸盐（［BMP］［BF₄］）、两种动力学抑制剂（KHIs）［聚乙烯基吡咯烷酮（PVP）和聚乙烯己内酰胺（PVCap）］及［BMP］［BF₄］与KHI的二元混合物对甲烷/乙烷/丙烷三元混合气体水合物生成动力学过程的影响规律。通过分析压力和气相组分变化规律，发现混合气体水合物呈现两步骤生长模式。在高过冷度（>10℃）和高搅拌速率（1000 r/min）条件下，单一添加剂基本失效，而［BMP］［BF₄］可较好协助增强PVCap的抑制性能。粉末X射线衍射和激光拉曼光谱测试结果均显示，所有体系中形成的水合物样品结构同时存在sⅠ型和sⅡ型，抑制剂的添加主要影响两种晶体结构的相对含量和各客体分子的笼子占有率。最后探讨了协同抑制机理。

关键词: 动力学抑制剂, 水合物, 离子液体, 聚合物, 机理

CLC Number:

TK 123

Zhen LONG, Jinhang WANG, Yong HE, Deqing LIANG. Characteristics study on hydrates formation from gas mixture under ionic liquid together with kinetic hydrate inhibitors[J]. CIESC Journal, 2023, 74(4): 1703-1711.

龙臻, 王谨航, 何勇, 梁德青. 离子液体与动力学抑制剂作用下混合气体水合物生成特性研究[J]. 化工学报, 2023, 74(4): 1703-1711.

Figures/Tables 9

Fig.1 Schematic diagram of high-pressure gas hydrate reaction

Fig.2 Pressure versus temperature curve during CH4/C2H6/C3H8 hydrate formation process with 1.0%（mass） PVPK90

Fig.3 Typical changes of pressure and temperature versus time during CH4/C2H6/C3H8 hydrate formed with 1.0%（mass） PVPK90 aqueous solution

Fig.4 Changes of pressure and temperature versus time during CH4/C2H6/C3H8 hydrate formed with pure water and 1.0%（mass） different inhibitors

Table 1 Gas compositions in vapor phase and hydrate phase at the end of reaction and total gas consumption in the presence of water or various inhibitors

体系	水合物相组分浓度/%(mol)			耗气量/mmol	气相组分浓度/%（mol)
体系	CH₄	C₂H₆	C₃H₈	耗气量/mmol	CH₄	C₂H₆	C₃H₈
纯水	83.77	10.13	6.1	86.5	99.41	0.54	0.05
[BMP][BF₄]	85.07	8.92	6.01	86.4	98.23	1.65	0.12
PVPK90	83.05	10.48	6.47	81.2	99.16	0.77	0.07
PVCap	82.80	10.57	6.63	78.4	98.91	0.97	0.12
PVPK90+[BMP][BF₄]	83.77	9.99	6.24	84.4	99.06	0.88	0.06
PVPCap+[BMP][BF₄]	52.78	23.37	23.85	20.2	96.82	2.83	0.32

Fig.5 PXRD patterns of CH4/C2H6/C3H8 hydrate formed in the presence of different additives

Fig.6 Typical Raman spectrum of CH4/C2H6/C3H8 hydrate formed with pure water （800—1200 cm-1: C—C region； 2800—3000 cm-1: C—H region； 3000—3400 cm-1： O—H region）

Table 2 Ratios of molecular diameters to cage diameters for some guest molecules［1］

客体分子	客体分子直径/Å	sⅠ型水合物		sⅡ型水合物
客体分子	客体分子直径/Å	5¹²	5¹²6²	5¹²	5¹²6⁴
CH₄	4.36	0.855	0.744	0.868	0.655
C₂H₆	5.5	1.08	0.939	1.1	0.826
C₃H₈	6.28	1.23	1.07	1.25	0.943

Fig.7 Raman spectrum of CH4/C2H6/C3H8 hydrate formed in the presence of different inhibitors

References 46

1	Sloan E D, Koh C A. Clathrate Hydrates of Natural Gases[M]. 3rd ed. Boca Raton, FL: CRC Press/Taylor & Francis, 2008.
2	Song Y C, Yang L, Zhao J F, et al. The status of natural gas hydrate research in China: a review[J]. Renewable and Sustainable Energy Reviews, 2014, 31: 778-791.
3	Boswell R, Collett T S. Current perspectives on gas hydrate resources[J]. Energy & Environmental Science, 2011, 4(4): 1206-1215.
4	Hammerschmidt E G. Formation of gas hydrates in natural gas transmission lines[J]. Industrial & Engineering Chemistry, 1934, 26(8): 851-855.
5	张剑波, 王志远, 刘书杰, 等. 深水气井测试过程中水合物流动障碍防治方法[J]. 石油勘探与开发, 2020, 47(6): 1256-1264.
	Zhang J B, Wang Z Y, Liu S J, et al. A method for preventing hydrates from blocking flow during deep-water gas well testing[J]. Petroleum Exploration and Development, 2020, 47(6): 1256-1264.
6	Wang Y H, Fan S S, Lang X M. Reviews of gas hydrate inhibitors in gas-dominant pipelines and application of kinetic hydrate inhibitors in China[J]. Chinese Journal of Chemical Engineering, 2019, 27(9): 2118-2132.
7	李锐, 宁伏龙, 张凌, 等. 低剂量水合物抑制剂的研究进展[J]. 石油化工, 2018, 47(2): 203-210.
	Li R, Ning F L, Zhang L, et al. Progress in the research of the low dosage hydrate inhibitors[J]. Petrochemical Technology, 2018, 47(2): 203-210.
8	陈玉川, 史博会, 李文庆, 等. 水合物动力学抑制剂的作用机理研究进展[J]. 化工进展, 2018, 37(5): 1726-1743.
	Chen Y C, Shi B H, Li W Q, et al. Progress of influence mechanism of kinetic hydrate inhibitors[J]. Chemical Industry and Engineering Progress, 2018, 37(5): 1726-1743.
9	董三宝, 田茂琳, 徐遥远, 等. 天然气水合物防聚剂研究进展[J]. 广东化工, 2021, 48(10): 82-85.
	Dong S B, Tian M L, Xu Y Y, et al. Progress in the investigation of natural gas hydrate anti-agglomerants[J]. Guangdong Chemical Industry, 2021, 48(10): 82-85.
10	Salmin D C, Estanga D, Koh C A. Review of gas hydrate anti-agglomerant screening techniques[J]. Fuel, 2022, 319: 122862.
11	Kelland M A, Dirdal E G, Ree L H S. Solvent synergists for improved kinetic hydrate inhibitor performance of poly(N-vinylcaprolactam)[J]. Energy & Fuels, 2020, 34(2): 1653-1663.
12	Xu S R, Fan S S, Fang S T, et al. Excellent synergy effect on preventing CH₄ hydrate formation when glycine meets polyvinylcaprolactam[J]. Fuel, 2017, 206: 19-26.
13	Lee W, Shin J Y, Cha J H, et al. Inhibition effect of ionic liquids and their mixtures with poly(N-vinylcaprolactam) on methane hydrate formation[J]. Journal of Industrial and Engineering Chemistry, 2016, 38: 211-216.
14	Rogers R D, Seddon K R. Ionic liquids: solvents of the future?[J]. Science, 2003, 302(5646): 792-793.
15	Xiao C W, Adidharma H. Dual function inhibitors for methane hydrate[J]. Chemical Engineering Science, 2009, 64(7): 1522-1527.
16	Xiao C W, Wibisono N, Adidharma H. Dialkylimidazolium halide ionic liquids as dual function inhibitors for methane hydrate[J]. Chemical Engineering Science, 2010, 65(10): 3080-3087.
17	Zare M, Kondori J, Zendehboudi S, et al. PC-SAFT/UNIQUAC model assesses formation condition of methane hydrate in the presence of imidazolium-based ionic liquid systems[J]. Fuel, 2020, 266: 116757.
18	Tariq M, Connor E, Thompson J, et al. Doubly dual nature of ammonium-based ionic liquids for methane hydrates probed by rocking-rig assembly[J]. RSC Advances, 2016, 6(28): 23827-23836.
19	Cha J H, Ha C, Kang S P, et al. Thermodynamic inhibition of CO₂ hydrate in the presence of morpholinium and piperidinium ionic liquids[J]. Fluid Phase Equilibria, 2016, 413: 75-79.
20	Long Z, Zhou X B, Shen X D, et al. Phase equilibria and dissociation enthalpies of methane hydrate in imidazolium ionic liquid aqueous solutions[J]. Industrial & Engineering Chemistry Research, 2015, 54(46): 11701-11708.
21	Nasir Q, Suleman H, Elsheikh Y A. A review on the role and impact of various additives as promoters/inhibitors for gas hydrate formation[J]. Journal of Natural Gas Science and Engineering, 2020, 76: 103211.
22	Farhadian A, Shadloo A, Zhao X, et al. Challenges and advantages of using environmentally friendly kinetic gas hydrate inhibitors for flow assurance application: a comprehensive review[J]. Fuel, 2023, 336: 127055.
23	Kim K S, Kang J W, Kang S P. Tuning ionic liquids for hydrate inhibition[J]. Chemical Communications, 2011, 47(22): 6341-6343.
24	Kang S P, Kim E S, Shin J Y, et al. Unusual synergy effect on methane hydrate inhibition when ionic liquid meets polymer[J]. RSC Advances, 2013, 3(43): 19920-19923.
25	Shen X D, Zhou X B, Liang D Q. Kinetic effects of ionic liquids on methane hydrate[J]. Energy & Fuels, 2019, 33(2): 1422-1432.
26	Shen X D, Shi L L, Long Z, et al. Experimental study on the kinetic effect of N-butyl-N-methylpyrrolidinium bromide on CO₂ hydrate[J]. Journal of Molecular Liquids, 2016, 223: 672-677.
27	任俊杰, 龙臻, 梁德青. 离子液体与PVP K90复合抑制剂对甲烷水合物的生成影响[J]. 化工学报, 2020, 71(11): 5256-5264.
	Ren J J, Long Z, Liang D Q. Effect of complex inhibitors containing ionic liquids and PVP K90 on formation of methane hydrate[J]. CIESC Journal, 2020, 71(11): 5256-5264.
28	Ren J J, Lu Z L, Long Z, et al. Experimental study on the kinetic effect of N-butyl-N-methylpyrrolidinium tetrafluoroborate and poly(N-vinyl-caprolactam) on CH₄ hydrate formation[J]. RSC Advances, 2020, 10(26): 15320-15327.
29	Lee D, Go W, Seo Y. Experimental and computational investigation of methane hydrate inhibition in the presence of amino acids and ionic liquids[J]. Energy, 2019, 182: 632-640.
30	Del Villano L, Kelland M A. An investigation into the kinetic hydrate inhibitor properties of two imidazolium-based ionic liquids on Structure Ⅱ gas hydrate[J]. Chemical Engineering Science, 2010, 65(19): 5366-5372.
31	Kang S P, Jung T, Lee J W. Macroscopic and spectroscopic identifications of the synergetic inhibition of an ionic liquid on hydrate formations[J]. Chemical Engineering Science, 2016, 143: 270-275.
32	Qureshi M F, Atilhan M, Altamash T, et al. Gas hydrate prevention and flow assurance by using mixtures of ionic liquids and synergent compounds: combined kinetics and thermodynamic approach[J]. Energy & Fuels, 2016, 30(4): 3541-3548.
33	Long Z, Zhou X B, Lu Z L, et al. Kinetic inhibition performance of N-vinyl caprolactam/isopropylacrylamide copolymers on methane hydrate formation[J]. Energy, 2022, 242: 123056.
34	Redlich O, Kwong J N S. On the thermodynamics of solutions; an equation of state; fugacities of gaseous solutions[J]. Chemical Reviews, 1949, 44(1): 233-244.
35	Chen G J, Guo T M. A new approach to gas hydrate modelling[J]. Chemical Engineering Journal, 1998, 71(2): 145-151.
36	Uchida T, Moriwaki M, Takeya S, et al. Two-step formation of methane-propane mixed gas hydrates in a batch-type reactor[J]. AIChE Journal, 2004, 50(2): 518-523.
37	Uchida T, Takeya S, Kamata Y, et al. Spectroscopic measurements on binary, ternary, and quaternary mixed-gas molecules in clathrate structures[J]. Industrial & Engineering Chemistry Research, 2007, 46(14): 5080-5087.
38	Kumar R, Linga P, Moudrakovski I, et al. Structure and kinetics of gas hydrates from methane/ethane/propane mixtures relevant to the design of natural gas hydrate storage and transport facilities[J]. AIChE Journal, 2008, 54(8): 2132-2144.
39	Daraboina N, Ripmeester J, Walker V K, et al. Natural gas hydrate formation and decomposition in the presence of kinetic inhibitors (3): Structural and compositional changes[J]. Energy & Fuels, 2011, 25(10): 4398-4404.
40	Cha M J, Shin K, Seo Y, et al. Catastrophic growth of gas hydrates in the presence of kinetic hydrate inhibitors[J]. The Journal of Physical Chemistry A, 2013, 117(51): 13988-13995.
41	Sharifi H, Englezos P. Accelerated hydrate crystal growth in the presence of low dosage additives known as kinetic hydrate inhibitors[J]. Journal of Chemical & Engineering Data, 2015, 60(2): 336-342.
42	Takeya S, Ripmeester J A. Anomalous preservation of CH₄ hydrate and its dependence on the morphology of hexagonal ice[J]. ChemPhysChem, 2010, 11(1): 70-73.
43	Subramanian S, Sloan E D. Trends in vibrational frequencies of guests trapped in clathrate hydrate cages[J]. The Journal of Physical Chemistry B, 2002, 106(17): 4348-4355.
44	Yagasaki T, Matsumoto M, Tanaka H. Adsorption mechanism of inhibitor and guest molecules on the surface of gas hydrates[J]. Journal of the American Chemical Society, 2015, 137(37): 12079-12085.
45	Xu J F, Li L W, Liu J X, et al. The molecular mechanism of the inhibition effects of PVCaps on the growth of sI hydrate: an unstable adsorption mechanism[J]. Physical Chemistry Chemical Physics, 2018, 20(12): 8326-8332.
46	Castillo-Borja F, Bravo-Sánchez U I. Molecular dynamics simulation study of the performance of different inhibitors for methane hydrate growth[J]. Journal of Molecular Liquids, 2021, 337: 116510.

[1]	Qi WANG, Bin ZHANG, Xiaoxin ZHANG, Hujian WU, Haitao ZHAN, Tao WANG. Synthesis of isoxepac and 2-ethylanthraquinone catalyzed by chloroaluminate-triethylamine ionic liquid/P₂O₅ [J]. CIESC Journal, 2023, 74(S1): 245-249.
[2]	Ruimin CHE, Wenqiu ZHENG, Xiaoyu WANG, Xin LI, Feng XU. Research progress on homogeneous processing of cellulose in ionic liquids [J]. CIESC Journal, 2023, 74(9): 3615-3627.
[3]	Minghao SONG, Fei ZHAO, Shuqing LIU, Guoxuan LI, Sheng YANG, Zhigang LEI. Multi-scale simulation and study of volatile phenols removal from simulated oil by ionic liquids [J]. CIESC Journal, 2023, 74(9): 3654-3664.
[4]	Shaoqi YANG, Shuheng ZHAO, Lungang CHEN, Chenguang WANG, Jianjun HU, Qing ZHOU, Longlong MA. Hydrodeoxygenation of lignin-derived compounds to alkanes in Raney Ni-protic ionic liquid system [J]. CIESC Journal, 2023, 74(9): 3697-3707.
[5]	Junfeng LU, Huaiyu SUN, Yanlei WANG, Hongyan HE. Molecular understanding of interfacial polarization and its effect on ionic liquid hydrogen bonds [J]. CIESC Journal, 2023, 74(9): 3665-3680.
[6]	Jiali ZHENG, Zhihui LI, Xinqiang ZHAO, Yanji WANG. Kinetics of ionic liquid catalyzed synthesis of 2-cyanofuran [J]. CIESC Journal, 2023, 74(9): 3708-3715.
[7]	Lei WU, Jiao LIU, Changcong LI, Jun ZHOU, Gan YE, Tiantian LIU, Ruiyu ZHU, Qiuli ZHANG, Yonghui SONG. Catalytic microwave pyrolysis of low-rank pulverized coal for preparation of high value-added modified bluecoke powders containing carbon nanotubes [J]. CIESC Journal, 2023, 74(9): 3956-3967.
[8]	Meisi CHEN, Weida CHEN, Xinyao LI, Shangyu LI, Youting WU, Feng ZHANG, Zhibing ZHANG. Advances in silicon-based ionic liquid microparticle enhanced gas capture and conversion [J]. CIESC Journal, 2023, 74(9): 3628-3639.
[9]	Yepin CHENG, Daqing HU, Yisha XU, Huayan LIU, Hanfeng LU, Guokai CUI. Application of ionic liquid-based deep eutectic solvents for CO₂ conversion [J]. CIESC Journal, 2023, 74(9): 3640-3653.
[10]	Lizhi WANG, Qiancheng HANG, Yeling ZHENG, Yan DING, Jiaji CHEN, Qing YE, Jinlong LI. Separation of methyl propionate + methanol azeotrope using ionic liquid entrainers [J]. CIESC Journal, 2023, 74(9): 3731-3741.
[11]	Jie CHEN, Yongsheng LIN, Kai XIAO, Chen YANG, Ting QIU. Study on catalytic synthesis of sec-butanol by tunable choline-based basic ionic liquids [J]. CIESC Journal, 2023, 74(9): 3716-3730.
[12]	Zehao MI, Er HUA. DFT and COSMO-RS theoretical analysis of SO₂ absorption by polyamines type ionic liquids [J]. CIESC Journal, 2023, 74(9): 3681-3696.
[13]	Rubin ZENG, Zhongjie SHEN, Qinfeng LIANG, Jianliang XU, Zhenghua DAI, Haifeng LIU. Study of the sintering mechanism of Fe₂O₃ nanoparticles based on molecular dynamics simulation [J]. CIESC Journal, 2023, 74(8): 3353-3365.
[14]	Xudong YU, Qi LI, Niancu CHEN, Li DU, Siying REN, Ying ZENG. Phase equilibria and calculation of aqueous ternary system KCl + CaCl₂ + H₂O at 298.2, 323.2, and 348.2 K [J]. CIESC Journal, 2023, 74(8): 3256-3265.
[15]	Linqi YAN, Zhenlei WANG. Multi-step predictive soft sensor modeling based on STA-BiLSTM-LightGBM combined model [J]. CIESC Journal, 2023, 74(8): 3407-3418.