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Microscopic study on the key process and influence of efficient synthesis of natural gas hydrate by in situ Raman analysis of water microstructure in different systems with temperature drop 被引量:1
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作者 Wei Zhang Chun-Gang Xu +2 位作者 Xiao-Sen Li Zhuo-Yi Huang Zhao-Yang Chen 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第7期317-333,I0008,共18页
Gas hydrate technology has considerable potential in many fields.However,due to the lack of understanding of the micro mechanism of hydrate formation,it has not been commercially applied so far.Gas hydrate formation i... Gas hydrate technology has considerable potential in many fields.However,due to the lack of understanding of the micro mechanism of hydrate formation,it has not been commercially applied so far.Gas hydrate formation is essentially a gas-liquid-solid phase transition of water and gas molecules at a certain temperature and pressure.The key to the hydrate formation is the transformation of water molecule from disordered arrangement to ordered arrangement.In this process,weakly hydrogen bonded water will be correspondingly converted to strongly hydrogen bonded water.Through in situ Raman analysis and experiments,the position change of the corresponding peaks of the strongly hydrogen bonded water and the weakly hydrogen bonded water was compared in this work,and the key microscopic process and influence of gas hydrate formation in different systems were comprehensively studied and summarized.It is found that,with the decrease of temperature,the OAH of the weakly hydrogen bonded water remains unchanged when the temperature drops to a certain value,which is the key to the transformation of water into cage hydrate rather than ice.The conversion from the weakly hydrogen bonded water to the strongly hydrogen bonded water is closely related to the gas-liquid interface force,the hydrophilicity/hydrophobicity of the promoter,the ionization degree of liquid,and the electrostatic field of the system.Among the four most common promoters,tetrahydrofuran(THF)has the highest efficiency in promoting methane(CH4)hydrate formation.Therefore,this study provides a scientific direction and basis for the development of high efficient hydrate formation promoters,which can effectively weaken the hydrogen bond of weakly hydrogen bonded water and promote the conversion of weakly hydrogen bonded water to strongly hydrogen bonded water. 展开更多
关键词 HYDRATE CONVERSION Hydrogen bonded water PROMOTER Micro mechanism
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Investigation of the hydrate formation process in fine sediments by a binary CO2/N2 gas mixture 被引量:2
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作者 Xiaoya Zang Lihua Wan Deqing Liang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2019年第9期2157-2163,共7页
To obtain the fundamental data of CO2/N2 gas mixture hydrate formation kinetics and CO2 separation and sequestration mechanisms,the gas hydrate formation process by a binary CO2/N2 gas mixture(50:50)in fine sediments(... To obtain the fundamental data of CO2/N2 gas mixture hydrate formation kinetics and CO2 separation and sequestration mechanisms,the gas hydrate formation process by a binary CO2/N2 gas mixture(50:50)in fine sediments(150–250μm)was investigated in a semibatch vessel at variable temperatures(273,275,and 277 K)and pressures(5.8–7.8 MPa).During the gas hydrate reaction process,the changes in the gaseous phase composition were determined by gas chromatography.The results indicate that the gas hydrate formation process of the binary CO2/N2 gas mixture in fine sediments can be reduced to two stages.Firstly,the dissolved gas containing a large amount of CO2 formed gas hydrates,and then gaseous N2 participated in the gas hydrate formation.In the second stage,all the dissolved gas was consumed.Thus,both gaseous CO2 and N2 diffused into sediment.The first stage in different experiments lasted for 5–15 h,and>60%of the gas was consumed in this period.The gas consumption rate was greater in the first stage than in the second stage.After the completion of gas hydrate formation,the CO2 content in the gas hydrate was more than that in the gas phase.This indicates that CO2 formed hydrate easily than N2 in the binary mixture.Higher operating pressures and lower temperatures increased the gas consumption rate of the binary gas mixture in gas hydrate formation. 展开更多
关键词 GAS HYDRATE FORMATION SEDIMENTS CO2/N2 MIXTURE
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Investigation of the methane hydrate surface area during depressurization-induced dissociation in hydrate-bearing porous media 被引量:1
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作者 Xuke Ruan Xiao-Sen Li 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2021年第4期324-334,共11页
The surface area of hydrate during dissociation in porous media is essentially important for the kinetics of hydrate dissociation.In this study,the methane hydrate surface area was investigated by the comparison resul... The surface area of hydrate during dissociation in porous media is essentially important for the kinetics of hydrate dissociation.In this study,the methane hydrate surface area was investigated by the comparison results of experiments and numerical simulations during hydrate decomposition in porous media.The experiments of methane hydrate depressurizationinduced dissociation were performed in a 1D high pressure cell filled with glass beads,an improved and valid 1D corescale numerical model was developed to simulate gas production.Two conceptual models for hydrate dissociation surface area were proposed based on the morphology of hydrate in porous media,which formed the functional form of the hydrate dissociation surface area with porosity,hydrate saturation and the average radius of sand sediment particles.With the establishment of numerical model for depressurizationinduced hydrate dissociation in porous media,the cumulative gas productions were modeling and compared with the experimental data at the different hydrate saturations.The results indicated that the proposed prediction equations are valid for the hydrate dissociation surface area,and the graincoating surface area model performs well at lower hydrate saturation for hydrate dissociation simulation,whereas at higher hydrate saturation,the hydrate dissociation simulation from the porefilling surface area model is more reasonable.Finally,the sensitivity analysis showed that the hydrate dissociation surface area has a significant impact on the cumulative gas production. 展开更多
关键词 Surface area Methane hydrate Hydrate dissociation Hydrate morphology DEPRESSURIZATION
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Research progress in hydrate-based technologies and processes in China:A review 被引量:7
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作者 Chungang Xu Xiaosen Li +3 位作者 Kefeng Yan Xuke Ruan Zhaoyang Chen Zhiming Xia 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2019年第9期1998-2013,共16页
Natural gas hydrate(NGH) is considered as an alternative energy resource in the future as it is proven to contain about 2 times carbon resources of those contained in the fossil energy on Earth. Gas hydrate technology... Natural gas hydrate(NGH) is considered as an alternative energy resource in the future as it is proven to contain about 2 times carbon resources of those contained in the fossil energy on Earth. Gas hydrate technology is a new technology which can be extensively used in methane production from NGH, gas separation and purification, gas transportation, sea–water desalination, pipeline safety and phase change energy storage, etc. Since the 1980s, the gas hydrate technology has become a research hotspot worldwide because of its relatively economic and environmental friendly characteristics. China is a big energy consuming country with coal as a dominant energy.With the development of the society, energy shortage and environmental pollution are becoming great obstacles to the progress of the country. Therefore, in order to ensure the sustainable development of the society, it is of great significance to develop and utilize NGH and vigorously develop the gas hydrate technology. In this paper,the research advances in hydrate-based processes in China are comprehensively reviewed from different aspects,mainly including gas separation and purification, hydrate formation inhibition, sea–water desalination and methane exploitation from NGH by CH4–CO2 replacement. We are trying to show the relevant research in China, and at the same time, summarize the characteristics of the research and put forward the corresponding problems in a technical way. 展开更多
关键词 GAS HYDRATE NATURAL GAS hydrate(NGH) CO2 SEPARATION HYDRATE formation INHIBITION CH4-CO2 REPLACEMENT
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Last glacial terrestrial vegetation record of leaf wax n-alkanols in the northern South China Sea:Contrast to scenarios from longchain n-alkanes 被引量:1
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作者 Shengyi Mao Guodong Jia +4 位作者 Xiaowei Zhu Nengyou Wu Daidai Wu Hongxiang Guan Lihua Liu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2022年第8期22-30,共9页
Long-chain n-alkanols and n-alkanes in core sediments from the northern South China Sea(SCS)were measured to make a comparison during terrestrial vegetation reconstruction from~42 ka to~7 ka.The results showed that te... Long-chain n-alkanols and n-alkanes in core sediments from the northern South China Sea(SCS)were measured to make a comparison during terrestrial vegetation reconstruction from~42 ka to~7 ka.The results showed that terrestrial vegetation record from long-chain n-alkanes matched well with previous studies in nearby cores,showing that more C_(4)plants developed during the Last Glacial Maximum(LGM)and C_(3)plants dominated in the interglacial period.However,these scenarios were not revealed by terrestrial vegetation reconstruction using long-chain n-alkanols,which showed C_(3)plant expansion during the LGM.The discrepancy during the interglacial period could be attributed to the aerobic degradation of functionalized long-chain n-alkanols in the oxygen-rich bottom water,resulting in poor preservation of terrestrial vegetation signals.On the other hand,the different advantages of functionalized n-alkanols and non-functional n-alkanes to record local and distal vegetation signals,respectively,may offer a potential explanation for the contradiction during the LGM when the SCS was characterized by low-oxygen deep water.Nevertheless,large variations on n-alkyl lipid compositions in C_(3)/C_(4)plants could play a part in modulating sedimentary long-chain n-alkanols and n-alkanes toward different vegetation signals,thereby suggesting that caution must be taken in respect to the terrestrial vegetation reconstruction using long-chain n-alkanes and long-chain n-alkanols. 展开更多
关键词 South China Sea long-chain n-alkanols long-chain n-alkanes Last Glacial Maximum terrestrial vegetation record
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Lipid biomarker composition in surface sediments from the Carlsberg Ridge near the Tianxiu Hydrothermal Field
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作者 Shengyi Mao Hongxiang Guan +5 位作者 Lihua Liu Xiqiu Han Xueping Chen Juan Yu Yongge Sun Yejian Wang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2021年第8期53-64,共12页
Hydrothermal venting has a profound effect on the chemical and biological properties of local and distal seawater and sediments. In this study, lipid biomarkers were analyzed to examine the potential influence of hydr... Hydrothermal venting has a profound effect on the chemical and biological properties of local and distal seawater and sediments. In this study, lipid biomarkers were analyzed to examine the potential influence of hydrothermal activity on the fate of organic matter(OM) in surface sediments around Tianxiu Hydrothermal Field in the Carlsberg Ridge(CR), Northwest Indian Ocean. By comparing the biomarker distributions of the samples with that of other typical hydrothermal sediments in the mid ocean ridge, it is shown that the location of the samples is not affected by the hydrothermal activity. The relatively low abundances of terrestrial n-alkyl lipids and riverine1,15-C_(32) diol suggested a minor contribution of terrigenous OM to the study area. The bacteria contributed predominantly to sedimentary marine OM;however, other marine source organisms, e.g., eukaryotes(i.e.,phytoplankton and fungi) could not be completely neglected. The marine-originated biomarkers showed significantly variable distributions between the two sediments, suggesting different dynamic physical and biogeochemical processes controlling the fate of marine OM. This study identified various diagnostic biomarkers(5,5-diethyl alkanes, diols and β-OH FAs), which may have significant environmental implications for future works in this region. 展开更多
关键词 Carlsberg Ridge Tianxiu Hydrothermal Field surface sediments biomarkers
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A Short-Cut Design Technique to Batch Distillation Column
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作者 Wenfeng Hao 《Advances in Chemical Engineering and Science》 2019年第3期263-279,共17页
The effects of equipment parameters of batch distillation column on the yield proportion are discussed and analyzed, the relations between maximal yield proportion and the column equipment parameters are correlated, w... The effects of equipment parameters of batch distillation column on the yield proportion are discussed and analyzed, the relations between maximal yield proportion and the column equipment parameters are correlated, which not only can be used to appraise rationality of the design parameters of the columns being employed and which but also can be used to new batch distillation column design. Under the assistance of the separation difficulty defined in this paper, the minimum number of theoretical plates is determined by the limit loss proportion method given, and further the actual number of theoretical plates and the height for the batch distillation are calculated by using the redundancy coefficient found to complete the whole design of the batch distillation as shown in the computational sample. Research showed that the actual number of theoretical plates and the height of batch distillation column with the column diameter 0.6 m are 17 and 5.1 m in alcohol mixture separation system of the sample proposed. Moreover, the approach can be extended to the design of batch distillation column with a separation system of multi-component liquid mixture after those adjacent components are treated as numerous binary component systems. 展开更多
关键词 Design Technique BATCH DISTILLATION COLUMN Separation DIFFICULTY REDUNDANCY Coefficient Theoretical Plate
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