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Post-stroke cognitive impairment (PSCI) is one of the most common complications after stroke. In recent years, as a complementary alternative therapy, many systematic reviews (SRs) and meta-analysis (MAs) have reported the efficacy and safety of acupuncture in improving cognitive function in patients with PSCI, but the quality of evidence is unknown and therefore needs to be evaluated comprehensively.We aimed to evaluate the SRs of acupuncture for patients with PSCI, to summarize the evidence quality of SRs to provide scientific evidence.We searched for relevant SRs and MAs in seven databases up to March 22, 2022. Two reviewers independently completed literature retrieval, screening, and data extraction. We used A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR 2) to evaluate the methodological quality; the Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool to determine the strength of evidence; and the ROBIS tool to assess RoB.We identified 14 SRs. The methodological quality of all SRs was low (2/14) or very low (12/14). GRADE results showed 13 were moderate quality (26%), 5 were low quality (10%), and 32 were very-low quality (64%). RoB showed that one SR had a low risk and 13 had a high risk. Moderate quality results showed that combined acupuncture therapy was superior to western medicine or cognitive rehabilitation training in improving cognitive function, the total response rate, and the daily living ability of patients with PSCI.Based on the evidence, acupuncture appears to be effective and safe in improving cognitive function for patients with PSCI, but the overall quality of SRs is not high. High-quality randomized controlled trials are needed to confirm the effectiveness and safety of acupuncture on the cognitive function of patients with PSCI.PROSPERO CRD42022315441.

Coal bed methane has been considered as an important energy resource. One major difficulty of purifying coal bed methane comes from the similar physical properties of CH4 and N2. The ZIF-8/water-glycol slurry was used as a medium to separate coal bed methane by fluidifying the solid adsorbent material. The sorption equilibrium experiment of binary mixture (CH4/N2) and slurry was conducted. The selectivity of CH4 to N2 is within the range of 2–6, which proved the feasibility of the slurry separation method. The modified Langmuir equation was used to describe the gas-slurry phase equilibrium behavior, and the calculated results were in good agreement with the experimental data. A continuous absorption–adsorption and desorption process on the separation of CH4/N2 in slurry is proposed and its mathematical model is also developed. Sensitivity analysis is conducted to determine the operation conditions and the energy performance of the proposed process was also evaluated. Feed gas contains 30 mol% of methane and the methane concentration in product gas is 95.46 mol% with the methane recovery ratio of 90.74%. The total energy consumption for per unit volume of product gas is determined as 1.846 kWh Nm−3. Experimental results and process simulation provide basic data for the design and operation of pilot and industrial plant.

We conducted the removal of hydrocarbons and concentrating of H2 from the tail gas of diesel hydrogenation (tail gas for short) using hydrate separation method. Based on the preliminary separation results, it is necessary to apply hydrate thermodynamic promoter to further improve the separation efficiency. In order to avoid the introduction of new impurity, we added propane (C3H8), one component of tail gas, in the feed gas as the hydrate promoter by reverse thinking, because it runs counter to the hydrocarbons removal from tail gas. The formation equilibrium conditions of tail gas hydrates were measured, and the enthalpy of hydrates equilibrium dissociation was calculated by the Clausius–Clapeyron equation. The results show that the addition of C3H8 significantly decreases the formation equilibrium pressure of tail gas hydrates at the same temperature. It indicates that C3H8 indeed performs as a thermodynamic promoter for tail gas hydrates. Consequently, the driving force for hydrates formation increases, and more hydrates form at the equilibrium state. As a result, the total removal rate of hydrocarbons and the recovery rate of H2 are both increased, while the concentration of H2 in equilibrium gas almost keeps unchanged. The results demonstrate that the addition of C3H8 behaves as an inducer to enclose relatively more hydrocarbons into hydrate phase, and it also accelerates the hydrates formation rate at the same time. This work presents a new research idea, i.e., cast a small fish for a big one, for the flexible and optimum application of hydrate separation technology.

In this work, the mixed porous liquid–solid made of zeolitic imidazolate framework-8 (ZIF-8), 2-methylimidazole (mIm), glycol, and water was first used in a pilot-scale packed system for CO2 captur...

Recovery of H2 and N2 from the tail gases of the ammonia synthesis plant could significantly improve the ammonia output and economic benefits. In this work, we measured the formation conditions of ...

Biogas is one of the green energy resources. To enhance usage of biogas (64.0 mol % CH4/CO2) and reduce the greenhouse effect, CH4 purification by the hydrate-based gas separation (HBGS) technology...

In teleost fish, sex steroids are involved in sex determination, sex differentiation, and fertility. Cyp17a1 (Cytochrome P450 family 17 subfamily A member 1) is thought to play essential roles in fish steroidogenesis. Therefore, to further understand its roles in steroidogenesis, sex determination, and fertility in fish, we constructed a cyp17a1 gene mutant in Nile tilapia (Oreochromis niloticus). In XX fish, mutation of the cyp17a1 gene led to a female-to-male sex reversal with a significant decline in 17β-estradiol (E2) and testosterone (T) production, and ectopic expression of male-biased markers (Dmrt1 and Gsdf) in gonads from the critical window of sex determination. Sex reversal was successfully rescued via T or E2 administration, and ovarian characteristics were maintained after termination of E2 supplementation in the absence of endogenous estrogen production in cyp17a1–/– XX fish. Likewise, deficiencies in T and 11-ketotestosterone (11-KT) production in both cyp17a1–/– XX sex-reversed males and cyp17a1–/– XY mutants resulted in meiotic initiation delays, vas deferens obstruction and sterility due to excessive apoptosis and abnormal mitochondrial morphology. However, 11-KT treatment successfully rescued the dysspermia to produce normal sperm in cyp17a1–/– male fish. Significant increases in gonadotropic hormone (gth) and gth receptors in cyp17a1–/– mutants may excessively upregulate steroidogenic gene expression in Leydig cells through a feedback loop. Taken together, our findings demonstrate that Cyp17a1 is indispensable for E2 production, which is fundamental for female sex determination and differentiation in XX tilapia. Additionally, Cyp17a1 is essential for T and 11-KT production, which further promotes spermatogenesis and fertility in XY males.

Background Heart failure (HF) is the final stage of cardiovascular disease development, and clinical studies on acupuncture for the treatment of HF are increasing. However, the efficacy and safety of these acupuncture methods are unclear. The purpose of this study is to conduct a meta-analysis of the relevant randomized controlled trials (RCTs) to explain their efficacy and safety through high-quality evidence. Methods The databases of the Cochrane Library, PubMed, Web of Science, SinoMed, China National Knowledge Infrastructure (CNKI), Wan-fang, and VIP will be searched from inception date to June 2021. The search will not be restricted by language. This study will include RCTs of various acupuncture methods for HF. Study selection, data extraction, and research quality assessments will be conducted independently by two researchers. The primary outcome is the efficacy rate and heart function, the secondary outcomes are quality of life scores, rehospitalization, and adverse reactions/events. The software RevMan 5.3 and Aggregate Data Drug Information System (ADDIS) will be used for network meta-analysis (NMA). Risk of bias, meta-regression, subgroup analysis, and sensitivity analysis will be performed, and the quality of evidence will be assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework. Discussion This study will confirm the efficacy and safety of acupuncture in improving the clinical symptoms and heart function of HF, or elucidate which method of acupuncture is better suited to this purpose.

Study on the gas hydrates in porous medium has great significance to the formation, accumulation and exploitation of natural gas hydrate (NGH). Consequently, we investigated the formation/dissociation of ethane hydrate in a sub-millimeter sized capillary in this work, and observed the appearance and kinetic rate during the hydrate formation/dissociation process. The dissociation equilibria of ethane hydrate in capillary was measured first, then the influences of hydrate memory effect (dissociation temperature and time) and degree of subcooling on ethane hydrate formation were obtained, respectively. The results demonstrate that hydrate forms more difficultly in capillary than in conventional macro-reactor because of the fluid resistance effect and poor mass transfer of gas-liquid. The appearance and formation kinetics of ethane hydrate are greatly influenced by the memory effect and subcooling degree. The morphology of ethane hydrate formation on the bubble surface in water bulk phase shows that “bridge effect” occurs during the hydrate formation and growth in capillary.

The structural transition of methane-ethane gas hydrates is generally observed during the forming process; however, it has seldom been reported during the dissociation process. Study on the dissociation behavior of methane-ethane hydrate below ice point has important implications on gas storage and transportation. It was also be helpful for the natural gas hydrate production by depressurization in permafrost zones. The dissociation of a series of methane-ethane hydrate samples at atmospheric pressure and temperatures below ice point (272.15–269.15 K) was performed, and the influence of gas composition and temperature on the structural transition was examined using in situ Raman spectroscopy. The hydrate structures were found to transition from structure I to structure II over a methane composition range of 50–68 mol%. The hydrates remained as sI or sII type compounds, and no structural transition occurred during the dissociation when the methane content in methane-ethane gas mixture was decreased to a certain amount (

The high efficiency separation of ethane from natural gas becomes significant due to the occurrence of revolution in shale gas. Herein a new approach of continuous sorption separation was developed...

The separation and utilization of coal bed methane have great research and economic significances. Consequently, we investigated the two-stage separation of CH4/N2 binary gas mixture, an analogue of coal bed methane, using hydrate separating method in this work. In order to realize green environmental protection and promote the popularization of hydrate separation method, two biological additives, i.e., tea polyphenol and catechin, were applied to recovery CH4 by forming bioclathrates. The influences of tea polyphenol and catechin on hydrates thermodynamic phase equilibria, kinetic hydration rate, gas storage capacity and separation effects were systematically studied. The results show that these two bio-additives could significantly increase the formation rate and gas storage capacity of hydrates in comparison with pure water system. In addition, the recovery of CH4 and separation factor are also enhanced in the presence of bio-promoters. Therefore, the formation of bioclathrates is helpful to protect environment, and promote the industrial application of the hydrate separation technology.

CH4 purification and CO2 removal by hydrate-based separation method from the simulated biogas (64 mol % CH4/CO2) were investigated in tetrabutylammonium bromide (TBAB) solution. Three different hyd...

The toxicity of hydrate inhibitors used in the field has attracted more attention. A natural material, i.e., whey protein, was assessed to act as kinetic hydrate inhibitors (KHIs) in a sapphire cell and an autoclave equipped with particle video microscope (PVM) and focused beam reflectance measurement (FBRM) probes. The pressure dropping method was utilized to estimate the hydrate induction time, and the results demonstrate that the hydrate inhibition performance of whey protein is superior to that of the commercial KHI, polyvinylpyrrolidone. The induction time for the pure water system was found to increase linearly with the increase in the dosage of whey protein until it reached approximately 2.5 wt%. As it is usually inevasible to apply KHIs under conditions of high water contents, the feasibility of whey protein as a KHI in the (oil + water) system with and without an emulsifier of Tween 20 was evaluated. A small amount of oil was found to have no obvious influence on the induction time for the system with whey protein under the circumstances without the addition of emulsifier. When Tween 20 was added, the induction time obviously increased under the same operating conditions, which could be attributed to the emulsifier–protein interactions in aqueous solutions. The oil drops decrease and are distributed more evenly with the increasing dosage of Tween 20 under the PVM and FBRM probes measurement. Additionally, the particles decrease during the hydrate formation process. This work presents a natural KHI and gives the inhibition discipline in a high-water-content system.

Alkyl polyglucosides have attracted great research interests as environmental-friendly biological surfactants. Consequently, we investigated the effects of n-hexyl polyglucoside and octyl-decyl pol...

[C8min] BF4 was used in this work to combine with TBAB or THF for the investigation about thermodynamic and kinetic additives on CO2 and CH4/CO2 hydrates. The results show that [C8min] BF4 has the inhibition effect on the equilibrium of hydrate formation. About the kinetic study, [C8min] BF4 could improve the rate of CO2 hydrate formation and increase the gas uptake in hydrate phase. At the same time, the combination of TBAB and [C8min] BF4 could increase the mole friction of CH4 in residual gas comparing with the data in THF solution. CH4 separation efficiency was strongly enhanced. Since that the size of CO2 and CH4 molecules are similar, CH4 and CO2 could form the similar hydrate, so the recovery of CH4 from biogas decreases lightly. The CH4 content in biogas can purified from 67 mol% to 77 mol% after one-stage hydrate formation. In addition, the combination of THF and [C8min] BF4 do not have obvious promoting effect on CH4 separation comparing with the gas separation results in pure THF solution.

The effects of mung starch on methane hydrate formation equilibria/rate and gas storage capacity were investigated in this work. Mung starch at three concentrations of 100, 500, and 800 ppm were tested comparing with the pure water. The results show that mung starch has slight thermodynamic promotion effect on methane hydrate formation, because it decreases the gas-liquid-hydrate three-phase equilibria pressure at the same temperature. The formation rate and gas storage capacity of methane hydrate in the presence of mung starch were studied at 8.0 MPa and 275.15 K–281.15 K. The results demonstrate that mung starch significantly accelerates methane hydrate formation rate. It could shorten the induction time and reaction time of methane hydration process. In addition, the gas storage capacity of methane hydrate is also increased greatly. The solubility data of methane indicate that mung starch indeed plays a role of solubility enhancement. The green and environmental friendly characteristics of mung starch could be helpful to promote the application of hydrate-based technology.

CH4 concentration and CO2 separation from biogas (CH4/CO2) by an one-stage hydrate formation was supposed to be a prospective and economical practicable technology compared with traditional gas sep...

In our previous work, a novel slurry approach that suspends zeolitic imidazolate framework-8 (ZIF-8) in solvents (glycol and glycol-2-methylimidazole) for CO2 capture was reported. This approach can efficiently remove CO2 from gas mixtures at normal pressure/temperature. In this work, a system with water coexistence was investigated for real CO2 capture application purposes. Our results show that the structure of the recovered ZIF-8 collapses in the presence of water during the CO2 capture process; however, ZIF-8 can keep its full crystallinity and gas adsorption/separation properties with 5 wt % mIm or more in liquid. Selectivity of CO2/CH4 reaches 76, and its value increases to 190 when 40 wt % mIm was added after four cycling times. Adding suitable mIm can protect the ZIF-8 structure in the environment containing CO2 and water.

It was documented that 17α, 20β-dihydroxy-4-pregnen-3-one (DHP), a fish specific progestin, might play critical roles in spermatogenesis, sperm maturation and spermiation partially through activating nuclear receptor (Pgr). However, no direct evidence is available to demonstrate the functions of DHP in fish spermatogenesis. To further elucidate the roles of DHP in teleosts, we generated a pgr homozygous mutant line in XY Nile tilapia (Oreochromis niloticus). Pgr gene mutation resulted in the development of a smaller, thinner testis and a lower GSI compared with normal testis. Pgr gene knockout led to irregular arrangement of spermatogenic cysts, decline of sperm count and sperm motility. Significant decrease of spermatocytes and spermatozoa was observed, which was further proved by the PCNA and Ph3 staining. Real-time PCR analysis demonstrated that mutation of pgr gene resulted in a significant up-regulation of steroidogenesis-related genes of cyp17a, cyp11b2, StAR, scc, 20β-HSD, and sf1, and down-regulation of fshb, fshr, oct4, sycp3, cdk1, prm, cyclinB1, cyclinB2 and cdc25 genes. Furthermore, both Immunohistochemistry and Western blotting experiments revealed a remarkable increase of Cyp17a1, Cyp17a2 and Cyp11b2 expressions in the pgr-/- testis. EIA measurement showed that an evident increase of 11-KT level was found in the pgr-/- XY fish. There was a significant increase in the mortality of offspring when crossing pgr-/- XY fish with wild type XX fish. Increased TUNEL staining and enhanced apoptosis maker gene (bax) expressions were also observed. Taken together, our data suggested that DHP-activated physiology via pgr is crucial for the fertility in the XY tilapia.

CO2 replacement is considered as a promising method for the simultaneous development of natural gas hydrate and CO2 sequestration. The addition of small molecular gases, such as N2 and H2, into the injected gas can increase the gas recovery ratio and prevent CO2 liquefaction. Based on previous studies, this work presents methane hydrate exploitation using the CO2/H2 continuous injection-production mode. The mechanism combines gas sweep with CH4/CO2 replacement. A series of experiments were carried out to optimize the injected gas composition and flow rate, which have a significant effect on the rate of CH4 hydrate decomposition, amount of CO2 sequestration, and cost. The compositions of the injected gases had little effect on the recovery rate when a relatively higher flow rate was employed. A balance between CH4 production and CO2 sequestration was established when the CO2 mole fraction was slightly

By dispersing zeolitic imidazolate framework-8 (ZIF-8) in different liquids composed of water, glycol, and 2-methylimidazole (mIm), a series of ZIF-8/water-glycol-mIm slurries were formed. The sorption isotherms of CO2 in these slurries, as well as in aqueous solution of mIm, were measured in the temperature range from 293.15 to 313.15 K. Next, the enthalpies of CO2 sorption in these slurries were correspondingly determined using the Clausius-Clapeyron equation. At the same time, the sorption kinetics and regeneration performances of the slurries were investigated. The results show that CO2 absorption in aqueous mIm solutions is dominated by chemical absorption, while in the ZIF-8/mIm-water-glycol slurry, CO2 uptake is determined by both chemical absorption and physical adsorption. Increasing ZIF-8 content in slurry can significantly increase the sorption capacity and decrease the sorption heat by increasing the physical adsorption contribution. Increasing ZIF-8 content can even increase the sorption rate within a certain content range. Although the presence of glycol decreases the sorption capacity and increases viscosity to a certain extent, it also significantly decreases the desorption heat. By considering sorption capacity, desorption heat, and viscosity, a particular ZIF-8 slurry recipe, i.e., solid fraction of 15–25.0 wt% and liquid composition of approximately mIm 25 wt% + water 40 wt% + glycol 35 wt%, is recommended, for which the CO2 sorption capacity can reach 1.6 mol/L (higher than that of some alkanol amine solutions) under ambient pressure and 313.15 K, while the desorption heat could be as low as 32 kJ/mol. The structure of ZIF-8 can remain intact in the CO2 capture process in the presence of mIm, i.e., the slurry could be regenerated perfectly.

The effects of temperature, pressure, initial promoter concentration and coal seam gas/liquid ratio on the separation of methane from coal seam gas were experimentally investigated. Low temperature, high pressure and high promoter concentration lead to high separation efficiency and high recovery rate of CH4, but reduce the CH4 capture selectivity in hydrate. Experimental simulation of a three-stage separation shows that CH4 can be concentrated from 34.6 to 81.3 mol% in the dissociated gas, while its content is only 7.2 mol% in the residual gas. An innovative model was established to predict the separation performance. The modeling results reasonably match the experimental data in predicting the effects of different influential factors, with an average relative deviation of 2.83%, the maximum relative deviation 11.2%, and the average relative variance 0.1044. The modeling results of a three-stage separation process include 81.0 mol% of CH4 in the final dissociated gas and 5.5 mol% of CH4 in the final residual gas. The recovery rate of CH4 was 90.1 mol% and the separation factor was 73.0.

Carbon-based materials, including graphene, porous carbon, and nanotubes, have been widely used as conductive additives to reduce the resistance in semiconductive anode materials of lithium-ion batteries (LIBs) toward better performance and the alleviated battery overheat problem. However, these additives are usually denounced for their low lithium-ion capacity. Moreover, emergence of vacant defect and heteroatom incorporation would open a sizable energy gap accompanied by reduced conductance. Here, by selecting MoS2 as a prototype system, we proclaim the utilization of emerging borophene as the conductive additive in terms of its low ion-transport barrier and robust metallic conductivity against defects and external doping in addition to its high Li-storage capacity. We found that substantial electrons transfer from MoS2 to borophene, producing strong electronic coupling that conduces to favorable interface bonding in combination with improved Li affinity. Incorporation of borophene also compensates the ...

The hydrate separation method for recovering hydrogen and ethylene from fluid catalytic cracking (FCC) dry gas was systematical investigated. We experimentally investigated the effects of different influential factors (temperature, pressure, the initial promoter concentration, the initial gas/liquid ratio) on the separation. The presence of the thermodynamic promoter reduces the hydrate formation pressure, but it also reduces the separation efficiency. The hydrate based separation method is efficient in the rough separation of FCC dry gas. After one stage separation, the concentration of H 2 was increased from 31.08% to 53.81% and the concentration of C 2 H 4 was increased from 47.17% to 75.91%. We propose an innovative model to calculate the separation results and the effects of different influential factors on the separation is well represented by the model. The average relative deviation (ARD) was 6.52%. In three stage separation computation, the concentration of H 2 was enhanced to 57.69% in H 2 rich gas and the concentration of C 2 H 4 was enhanced to 85.79% in C 2 H 4 rich gas. The recovery rate was 99.99% for H 2 and 83.77% for C 2 H 4 . The separation factor was 753.97 for H 2 and 37.39 for C 2 H 4 .

The conventional hydrate promoters and inhibitors, such as tetrahydrofuran (THF), sodium dodecyl sulfate (SDS) and methanol, have the common disadvantages of chemical substances, i.e., pungent flavor, corrosivity, toxicity and anti-degradability. It severely pollutes the environment and limits the application of hydrate-based technologies. Consequently, it is necessary to develop new and green substances as the hydrate promoters or inhibitors. In this work, L-arginine and isooctyl glucoside were used as bio-additives for CH 4 hydrate to form bio-hydrate. The effects of L-arginine and isooctyl glucoside on the formation thermodynamics and kinetics of CH 4 hydrate were investigated first. Then, the equilibrium separation of CH 4 /N 2 via hydrates formation was conducted in isooctyl glucoside solution. The results show that formation pressure of CH 4 hydrate in L-arginine solution is higher than that in pure water at the same temperature. Isooctyl glycosidase can greatly accelerate the hydration rate and increase the gas storage capacity of hydrate. In the separation of CH 4 /N 2 , the recovery of CH 4 and gas storage capacity of hydrate are significantly increased after adding isooctyl glucoside in water. In conclusion, L-arginine can be used as hydrate inhibitor to replace conventional alcohols in the inhibition of hydrates formation. Isooctyl glycosidase is an effective kinetic promoter of hydrate, which is suitable for CH 4 storage in hydrate, and separation of CH 4 -containing gas mixture via hydrates formation. This work provides two environment friendly bio-additives for hydrate, which will definitely promote the development and application of hydrate research.

Pipe plugging and cracking caused by gas hydrate blockage is the major problem in oil/gas flow assurance, especially in deep subsea pipelines. Thermodynamic inhibitors(THIs) are one of the effective methods to inhibit the formation of gas hydrate. This work evaluates the thermodynamic inhibition effect of D-sorbitol, a polyhydroxy compound, for both methane ( C H 4 ) and carbon dioxide ( C O 2 ) hydrates. The gas-liquid-hydrate equilibrium (GLHE) conditions for C H 4 and C O 2 were measured by the isothermal pressure search method in the presence of aqueous D-sorbitol solutions (1.00, 2.00, 3.00 mol%). The equilibrium pressure change ( Δ P ) and hydrate dissociation enthalpies ( Δ H d i s s ) were used to reflect the thermodynamic effects of D-sorbitol on C H 4 and C O 2 hydrates. The Δ P data show that D-sorbitol has an obvious inhibition impact on C H 4 and C O 2 hydrates formation. Compared with deionized water system, C H 4 hydrate GLHE pressure increased by 11.6, 25.0, 41.4%, while C O 2 hydrate GLHE pressure increased by 10.1, 18.6, 32.7% in 1.00, 2.00, 3.00 mol% D-sorbitol solutions, respectively. The Δ H d i s s data demonstrate that D-sorbitol does not participate in the formation of the hydrate crystal structure. Chen-Guo hydrate thermodynamic model and Wilson activity model were applied to predict the GLHE conditions of both C H 4 and C O 2 hydrates in the presence of D-sorbitol. The calculated results can well match the experimental values. The average relative deviations (ARD) between calculated and experimental data for C H 4 and C O 2 hydrate are less than 2.39% and 3.76%, respectively. D-sorbitol is a non-toxic and environment-friendly compound. The results in this work indicate that D-sorbitol can be applied to flow assurance strategies for hydrate blockage prevention.

A large amount of fluid catalytic cracking (FCC) dry gas, which contains high concentrations of ethylene and hydrogen, is used as low heat value fuel or simply flared every year, resulting in not only a waste of resources but also greenhouse gas emission. This study provides a continuous hydrate separation technology to solve this problem. The FCC dry gas flow was continuously separated into two gas flows: a C 2 H 4 -rich, low H 2 stream and a residual gas stream with low C 2 H 4 and high H 2 contents. This paper experimentally investigated the effects of temperature and the concentration of tetra butyl ammonium bromide (TBAB) on the hydrate forming pressure of FCC dry gas, the time evolution of the gas compositions and the gas flow rates during long-term operation of the hydrate-based separation, and the effects of different influential factors on the separation. The concentration of C 2 H 4 was increased from 47.17% to 71.56%, and the maximum recovery rate of C 2 H 4 reached 90.47%. The maximum separation factor of ethylene was 8.13. The concentration of H 2 was increased from 31.08% to 63.60%, and the maximum recovery rate of H 2 was 91.45%. The maximum separation factor of hydrogen was 8.87.

In this work, a calculation model of CO2 solubility in equilibrium with hydrate was developed on the base of the Patel-Teja equation of state and Chen-Guo hydrate model. The solubility of CO2 in water and NaCl solution in equilibrium with hydrate were calculated respectively under the temperature window of 273.95 K to 282.55 K and the pressure window of 2.0 MPa to 8.0 MPa. The comparisons between the calculating and experimental values show that the average absolute deviations percentages (AADP) are 2.12% for the CO2/H2O system and 2.31% for the CO2/NaCl/H2O system, respectively. It demonstrates that the model proposed in this work could well predict the solubility of CO2 in NaCl solution in equilibrium with hydrate. This article is protected by copyright. All rights reserved

Carbon dioxide (CO2) is often used as a process fluid in oil and gas reservoirs for enhancing the oil recovery. The interfacial tension of CO2 with hydrocarbons is an important thermophysical property for the design of such processes. The systematical measurements of equilibrium interfacial tensions for systems of (CO2 + single n-alkane) are currently scarce. In this work, the interfacial tensions of 11 (CO2 + n-alkane) binary systems were measured by the pendant drop method at temperatures of (323.15 and 353.15) K. The carbon number of n-alkane ranged from 10 to 20. The influences of temperature, pressure, and chain length of n-alkane on the interfacial tension were investigated. Additionally, the density gradient theory was applied to compute the surface tensions of these binary mixtures combined with the Patel–Teja equation of state plus volume translation approach. The calculation results are in good agreement with the experimental data.