ENERGY & FUELS
·
2021
·
IF 3.605
Xianwen Cheng,Qiyu Huang,Dongxu Zhang,Yang Lyu,Wei Wang,Rongbin Li,Yijie Wang,Qiuchen Wang
In order to evaluate the influence of asphaltene polarity on the behaviors of hydrates, four subfractions with different polarities fractionated from asphaltenes are used for hydrate nucleation, growth, and dissociation experiments. It is found that the subfraction with higher polarity shows a higher self-aggregate tendency in emulsions and tends to adsorb less at the oil–water interface, which is mainly caused by its larger C/H ratio and higher aromaticity. The addition of asphaltenes increases the induction time of hydrates, and this effect is strengthened in the emulsion with the less polar subfraction. The calculation results of total gas consumption indicate that the amount of formed hydrate decreases with the increase of asphaltenes, especially in the emulsion with the higher polarity subfraction. Moreover, asphaltene subfractions are observed to accelerate the dissociation process of hydrates.
研究领域:
石油化学
·
胶体与界面科学
·
能源材料
·
流体力学
·
相变过程
✓ 已验证
DOI
高影响因子
Journal of Marine Science and Engineering
·
2022
·Vol. 10
·期 4
·548
·
IF 2.744
Haopeng Zeng,Yu Zhang,Lei Zhang,Zhaoyang Chen,Xiaosen Li
Most resources of natural gas hydrate (NGH) exist in marine sediments where salts and sea mud are involved. It is of great importance to investigate the effects of salts and sea mud on NGH formation kinetics. In this study, the mixture of silica sand and montmorillonite was used to mimic sea mud. The effects of the NaCl concentration of pore water and montmorillonite content on methane hydrate formation were studied. A low NaCl concentration of 0.2 mol/L and a low montmorillonite content range of 10–25 wt% is beneficial to reduce the induction time of hydrate formation. The high NaCl concentration and high content of montmorillonite will significantly increase the induction time. The average induction time for the experiments with the NaCl concentrations of 0, 0.2, 0.6, and 1.2 mol/L is 20.99, 8.11, 15.74, and 30.88 h, respectively. In the pure silica sand, the NaCl concentration of 0.2 mol/L can improve the final water conversion. In the experiments with pure water, the water conversion increases with the increase of the montmorillonite content due to the improvement of the dispersion of montmorillonite to water. The water conversion of the experiments in pure water with the montmorillonite contents of 0, 10, 25 and 40 wt% is 12.14% (±1.06%), 24.68% (±1.49%), 29.59% (±2.30%), and 32.57% (±1.64%), respectively. In the case of both montmorillonite and NaCl existing, there is a complicated change in the water conversion. In general, the increase of the NaCl concentration enhances the inhibition of hydrate formation and reduces the final water conversion, which is the key factor affecting the final water conversion. The average water conversion of the experiments under the NaCl concentrations of 0, 0.2, 0.6 and 1.2 mol/L is 24.74, 15.14, 8.85, and 5.74%, respectively.Keywords:methane hydrate;NaCl concentration;montmorillonite;hydrate formation kinetic
研究领域:
化学工程
·
地质学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Hong-Nan Chen,Yi-Fei Sun,Ming-Long Wang,Jin-Rong Zhong,Dan Rao,Chang-Yu Sun,Guang-Jin Chen
CO 2 hydrate provides an important alternative solution for CO 2 geological sequestration. However, fingering flow of liquid CO 2 and hydrate membrane effect can severely restrict flowing CO 2 conversion to hydrate. Here we report an enhanced CO 2 hydrate sequestration method via CO 2 -H 2 O emulsion injection, and its effectiveness has been proven in a three-dimensional system. Compared to liquid injection, emulsion injection demonstrated higher displacement efficiency of pore water and larger sweep area, finally increasing CO 2 sequestration density by 142 %. The highly dispersed CO 2 micro-droplets significantly increase CO 2 -H 2 O contact capability and weakens the hydrate membrane effect, thereby greatly increasing the rate and quantity of hydrate conversion. For different water contents, the highest CO 2 sequestration density of 148 kg/m 3 is achieved at 40 % water content, with hydrated CO 2 accounting for 71.45 %. The excellent performance of CO 2 -H 2 O emulsion provides a green and high-efficient approach to CO 2 hydrate sequestration.
研究领域:
环境科学
·
地质学
✓ 已验证
产品关联
DOI
高影响因子
CRYSTENGCOMM
·
2021
·Vol. 23
·期 48
·8588-8600
·
IF 3.545
Jing Zhang,Wenjun Zhang,Christine V. Putnis,Lijun Wang
As one of the most ubiquitous biominerals, calcium oxalate (CaOx) exhibits different hydrate phases. Although the monohydrate (whewellite, COM) is the thermodynamically favorable phase at ambient temperatures, the metastable dihydrate (weddellite, COD) can still stably exist in pathological mineralization but the stabilization mechanisms remain unclear. Herein, the in situ phase transformation of nano-sized COD to COM in the presence of citrate (CA) and zinc ions (Zn2+) as stabilizers was observed by time-resolved atomic force microscopy (AFM) and Raman spectroscopy. By a combination of zeta potential measurement, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), we demonstrate that CA can form a protective layer on the surface of nano-sized COD crystals to inhibit aggregation and delay the phase transformation of COD to COM. Due to the stabilizing/destabilizing effect of CA on the specific faces of COD, atypical-shaped COD crystals form. In addition, Zn2+ can substitute Ca2+ sites within the COD unit cell, shrinking the COD structure by compressing the “zeolite-like” channels to reduce weakly-bonded interchannel H2O molecules. This generates relatively smaller and more stable COD crystals with a typical pyramid shape to further retard COM formation. The obtained results provide new insights into modulating the stability of the metastable CaOx phases for potential control over pathological mineralization.
研究领域:
生物矿化
·
病理学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Xue Zou,Mucong Zi,Tiantian Wu,Yuanxin Yao,Caifeng Yang,Daoyi Chen
Kinetic hydrate inhibitors (KHIs) have gradually gained more attention in the natural gas and oil transportation field due to their remarkable inhibition performance at low dosages. However, the inhibition performance of most commercial KHIs is poor under high subcooling conditions. In this work, a radical polymerization method was used to synthesize four new KHIs by introducing the 1-vinylimidazole (VI) or vinylacetate (VAc) monomer. These newly-synthesized copolymer KHIs were characterized by Fourier Transform Infrared, 1 H nuclear magnetic resonance, and gel permeation chromatography, respectively. The cloud point of HY-201 is remarkably as high as 92.3 °C and the four KHIs are all biodegradable. Under subcooling of 10 K and 15 K, the inhibitory performance of four new KHIs and three commercial KHIs on hydrate nucleation and growth are as follows: PVP < Luvicap EG < Inhibex 501 < HY-101 < HY-201 < HY-301 < HY-401. In addition, the hydrate volume fraction of the four new KHIs at the optimal concentration of 15 K subcooling for 12 h was 13.3 %, 1.7 %, 2.4 %, and 2.1 %, respectively, which did not exceed 1/3 of the tested commercial KHIs. Further, the novel mechanism hypothesis is proposed as follows: the surface charge of the hydrate nuclei is neutralized by KHIs, and the hydrate nuclei aggregates, hindering the gas from entering the hydrate. In addition, the strong entanglement and adsorption of KHIs molecules with better inhibition performance make the hydrate lose the space for growth and expansion. Overall results highlight the great application prospects of these new KHIs in natural gas transmission based on the remarkable inhibition performance under high subcooling conditions.
研究领域:
石油与天然气工程
·
化学工程
·
材料科学
·
环境友好材料
·
流体输送
✓ 已验证
DOI
高影响因子
LANGMUIR
·
2020
·
IF 3.557
Guangchun Song,Yuanxing Ning,Yuxing Li,Wuchang Wang
In oil industry, the coexistence of hydrate and wax can result in a severe challenge to subsea flow assurance. In order to study the effects of wax on hydrate growth at the oil–water interface, a series of microexperiments were conducted in a self-made reactor, where hydrates gradually nucleated and grew on the surface of a water droplet immersed in wax-containing oil. According to the micro-observations, hydrate shells formed at the oil–water interface in the absence of kinetic hydrate inhibitor (KHI). The roughness and growth rate of hydrate shells were analyzed, and the effects of wax were investigated. In addition, vertical growth of the hydrate shell was observed in the presence of wax, and a mechanism was proposed for illustration. In the presence of KHI, small hydrate crystals formed separately at the oil–water interface instead of hydrate shells. The presence of KHI reduced the growth rate of hydrates and changed the wettability of hydrates. Moreover, the presence of wax showed no obvious effect on the effectiveness of KHI under experimental conditions.
研究领域:
石油工程
·
化学工程
✓ 已验证
DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2016
·
IF 2.196
Jia-nan Zheng,Ming-jun Yang,Yu Liu,Da-yong Wang,Yong-chen Song
Cyclopentane (CP) is considered to be a potential co-guest molecule in carbon dioxide (CO 2 ) hydrate-based desalination. The experimental thermodynamic data of CO 2 -CP hydrates were measured for a salt solution, where CP was chosen as a hydrate promoter. Seven experimental cases (62 cycles) were studied with different molar ratios of CP/water (0, 0.0025, 0.005, 0.0075, 0.01, 0.02, and 0.03). Hydrate phase equilibrium data were generated using an isochoric method, and the hydrate saturations were calculated based on gas uptake. The results indicated that the increase in CP concentration significantly decreased the CO 2 hydrate equilibrium pressure to a certain limit; the hydrate saturation also decreased during this process. Also, it was determined that CP encouraged the formation of s-II double CO 2 -CP hydrates, which are different from s-I simple CO 2 hydrate. The CO 2 -CP guest provides a strengthened stability and moderate hydrate phase equilibrium conditions for hydrate-based desalination. The recommended optimal molar ratio of CP is 0.01 when the increase in equilibrium was more than 10 K, and the decrease in hydrate saturation was less than 2%.
研究领域:
化学工程
·
环境科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2023
·
IF 15.1
Yaning Kong,Fei Wang,Guodong Zhang,Xiaolin Wang
It is anticipated to achieve safe, economical, and high-density hydrogen storage via hydrate, but sluggish formation kinetics of H 2 hydrate and low hydrogen storage capacity limit its application, and appropriate kinetic promoters are required to improve the situation. In this work, three nano promoters were prepared by soap-free emulsion polymerization method, the functional groups of -SO 3 − , –COO − and -N(CH 3 ) 3 + were separately immobilized on nano spheres to produce the nano promoters of -SO 3 − @PSNS, –COO − @PSNS and -N(CH 3 ) 3 + @PSNS, and their influence on the formation kinetics of mixed H 2 /THF hydrate was evaluated, while the performance of conventional kinetic promoters of methane hydrate was also estimated for comparison. It was found that the formation kinetics of mixed H 2 /THF hydrate was enhanced in the presence of nano promoters, which improve early growth of H 2 /THF hydrate and later water-to-hydrate conversion, leading to large hydrogen storage capacity. -SO 3 − @PSNS causes H 2 /THF hydrate to be looser and performs the best among the three nano promoters, hydrogen storage capacity in -SO 3 − @PSNS system is up to 0.467 wt% at 12 MPa, which increase by 39.8% comparing with that in pure THF system, and satisfactory hydrogen storage capacity of 0.303 wt% was also obtained under milder condition (7 MPa). For conventional kinetic promoters, L-methionine performs the best and shows similar promotion effect like -SO 3 − @PSNS, but it is excluded for large-scale industrial application when taking its high cost and perishable nature into consideration, whereas this scenario is improved by the proposed nano promoters.
研究领域:
化学工程
·
能源科学
✓ 已验证
DOI
高影响因子
FUEL
·
2024
·
IF 6.7
Yuhuan Bu,Zilong Lu,Chang Lu,Huajie Liu,Shenglai Guo,Hexing Liu,Rui Ma,Zhen Zhang,Mengran Xu
Deepwater cementing technology holds non-negligible significance in ensuring the safe exploitation of deepwater oil and gas resources, and maintaining stability of hydrate formations is crucial for deepwater cementing. Traditional solutions primarily focus on reducing the cement’s hydration heat evolution but fail to effectively address the issue of hydrate dissociation. Therefore, our previous work outlined the design and optimization of a novel hydrate dissociation inhibitor, PVCap/dmapma, and its physical synthesis and evaluation are explored in this study. The method of molecular simulation and experimental study was utilized to establish an evaluation method of hydrate dissociation inhibitor under cementing environment, to investigate the hydrate decomposition inhibitory, and to determine the relatively optimal synthesis conditions and process. PVCap/dmapma exhibits excellent ability to delay the hydrate dissociation, and no adverse effects on cement thickening and mechanical properties compared to Lecithin. Our findings provide a certain theoretical foundation for the development of hydrate dissociation inhibitors for cementing and hold significant implications for ensuring the safe exploitation of deepwater oil and gas resources.
研究领域:
石油工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL THERMODYNAMICS
·
2024
·
IF 2.2
Jing Xia,Zhigao Sun
Thermodynamic inhibitors may be used to inhibit hydrate formation in industry. Alcohol substances, due to their hydrophilic hydroxyl groups in their molecular structure, are prone to form hydrogen bond with water molecules to inhibit hydrate formation. In this work, sec -butyl alcohol is chosen to study the effects on CO 2 hydrate dissociation equilibrium conditions, where the step-heating method is utilized to obtain hydrate equilibrium conditions. The equilibrium curve of carbon dioxide hydrate dissociation moves to the region of lower temperatures or higher pressures. The higher mass fraction of sec -butyl alcohol, the better effect of inhibiting hydrate formation. Sec-butyl alcohol can be used as a thermodynamic hydrate inhibitor.
研究领域:
化学工程
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2022
·
IF 4.654
Changhong Yu,Cheng Yue,Baojiang Sun,Xin Yang,Jiakai Ji,Zilong Meng,Litao Chen
Hydrate can easily form and cause plugging in offshore oil and gas pipelines. As the managing strategy moves from full avoidance to dynamic control, antiagglomerants (AAs) could be an economical and efficient option for hydrate management. Searching for new efficient hydrate AAs is always needed. In this work, the antiagglomerating performances of 57 commercial chemicals, including cationic surfactants, zwitterionic surfactants, nonionic surfactants, and polymers, to methane hydrate in an oil–gas–water system were evaluated by using a rocking-cell apparatus. The slider-moving trajectories were recorded during hydrate formation. The performances of AAs were evaluated based on the slider-moving profiles at various hydrate fractions. It was found that cocamidopropyl dimethylamine, a nonionic surfactant that is labeled as an A class AA, could fully avoid hydrate plugging when the hydrate fraction was under 18.76%. The slider-moving trajectory in the full range of the cell indicated that the hydrate was well-dispersed in the liquid phase. Besides, 23 chemicals mainly from cationic and zwitterionic surfactants, which are labeled as B class AAs, could partially avoid hydrate plugging at various hydrate fractions (10.96–19.92%). The slider could move in a partial range of the cell, indicating that the hydrate may agglomerate and accumulate at the end of the cell. The rest of the chemicals were labeled as class C AAs, with which the slider was fully stuck. The working mechanism is discussed for an insightful understanding on the antiagglomerating performances of the screened AAs. Chemicals with a combined presence of an amide group and an amine group exhibit great potential for hydrate antiagglomeration, while the hydrogen-bonding ability of the hydrophilic amine headgroup may be adversely affected by the incorporation of anions.
研究领域:
化学工程
·
能源科学
·
材料科学
✓ 已验证
DOI
高影响因子
Geoenergy Science and Engineering
·
2023
·
IF 0
Hengfeng Shan,Youhong Sun,Bing Li,Yifeng Shen,Yun Qi,Guobiao Zhang
Hydraulic fracturing has been proven useful for improving the gas production efficiency of low-permeability hydrate reservoirs. However, no specific fracturing fluid system exists for marine hydrate reservoirs. Applying conventional water-based fracturing fluids in low-temperature (<293.2 K) marine hydrate reservoirs can lead to difficulties in gel-breaking and hydrate instability caused by external additives. In this study, we developed two water-based fracturing fluid systems that exhibited good gel-breaking performance at low temperatures (278.2–288.2 K), one comprising ammonium persulfate (APS), ferrous sulfate (FeSO 4 ), and citric acid (CA), the other APS and triethanolamine (TEA). In addition, we investigated the influence of crosslinking and gel-breaking reactions of the fracturing fluids on the methane hydrate phase equilibrium . The breaking time of the APS-FeSO4-CA system at 278.2K, 283.2K, and 288.2K was 30 min, 75 min, and 120 min respectively. On the other hand, the APS-TEA system accomplished the same task in 3 h, 6 h, and 10 h respectively. Furthermore, methane hydrate phase-equilibrium data showed that the fracturing fluid's three states, base fluid (BF), fracturing fluid gel (FFG), and gel-breaking liquid (GBL), all exerted an inhibitory effect on the phase equilibrium, with the hydrate suppression temperature (ΔT) ranging from 0.4 to 1.0 K. The differences in their inhibitory effect were primarily related to the micromorphology of the hydroxypropyl guar gum (HPG) molecules and the number of active hydroxyl (-OH) groups in the solution. Cryo-scanning electron microscopy (SEM) measurements revealed that the micromorphology of HPG in BF, FFG, and GBL transformed from regular ribbon-like structures to 3-D network structures and then to hole-containing, short ribbon-like structures. FFG formed a regular 3-D network structure after adding crosslinking agents to the BF. The ΔT values reversed from FFG < BF to FFG > BF when the HPG concentration increased from 0.3 wt% to 0.5 wt%, possibly due to the difference in the HPG molecules' water adsorption capacity before and after crosslinking. The broken HPG molecules with OH − groups in the solution were transformed into residues after gel-breaking, decreasing the GBL's inhibitory effect. Therefore, our results indicated that micromorphology variations could cause differences in the HPG molecules' water adsorption capacity, ultimately leading to ΔT differences. Based on our findings, the gel-breaking fracturing fluid systems we developed demonstrated potential for optimizing hydraulic fracturing in marine hydrate reservoirs.
研究领域:
石油工程
·
化学工程
✓ 已验证
DOI
危险品化学品经营许可证（带存储）