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With the development of the world economy, the energy crisis and environmental pollution have become global issues. Polygeneration systems, which have the advantages of energy saving and high efficiency, can alleviate them. This work proposed a novel combined cooling, heating, and power system structure composed of a gas turbine cycle, a supercritical CO2 (sCO2) cycle, an absorption refrigeration chiller, a steam generator, an organic Rankine cycle (ORC), and additional thermoelectric generator modules. The techno-economic-environmental performance of the proposed system was discussed through a comparative study of different integrated system structures. A parametric study was also conducted to analyze the effects of important decision variables, and then a multi-objective optimization was conducted to further study the system performance from different objectives. Finally, two different system structures were compared based on the optimal results. The results showed that the thermal efficiency was increased by 0.3% with the presence of a thermoelectric generator under design conditions, but it resulted in a higher cost rate of 0.45 $/h and larger emissions of approximately 0.19 kt CO2,eq. The optimal results revealed that the system had thermal efficiency of 67.88%, exergy efficiency of 42.62%, total cost rate of 10.60 $/h, and total emissions of 923.55 kt CO2,eq. Furthermore, a comparative study found that the proposed system structure exhibited excellent thermodynamic performance but worse economic performance than the integration of the sCO2 cycle and ORC.
Shukun Wang; Lu Zhang; Chao Liu; Zuming Liu; Song Lan; Qibin Li; Xiaonan Wang. Techno-economic-environmental evaluation of a combined cooling heating and power system for gas turbine waste heat recovery. Energy 2021, 231, 120956 .
AMA StyleShukun Wang, Lu Zhang, Chao Liu, Zuming Liu, Song Lan, Qibin Li, Xiaonan Wang. Techno-economic-environmental evaluation of a combined cooling heating and power system for gas turbine waste heat recovery. Energy. 2021; 231 ():120956.
Chicago/Turabian StyleShukun Wang; Lu Zhang; Chao Liu; Zuming Liu; Song Lan; Qibin Li; Xiaonan Wang. 2021. "Techno-economic-environmental evaluation of a combined cooling heating and power system for gas turbine waste heat recovery." Energy 231, no. : 120956.
Lubricant plays an important role in thermodynamic systems to lubricate the sliding surfaces. However, the mixing of working fluid and lubricant will significantly affect the heat transfer capacity of the system. Therefore, molecular dynamics simulations are employed to investigate the effects of lubricant PEC4 on the evaporation and boiling processes of R1234ze(E) in this paper. The results indicate that the evaporation and boiling process of R1234ze(E) is suppressed by the addition of PEC4 molecules. Additionally, PEC4 molecules will gradually replace R1234ze(E) molecules to absorb on Cu surface with the increase of PEC4 mass fraction. Then, an oil film will be formed on Cu surface and weaken the heat transfer capacity at the fluid–solid interface. The thermal resistance length is employed to evaluate the heat transfer capacity of the system. The result shows that the increase of the mass fraction of PEC4 will lead to an increase of temperature jump and thermal resistance length, which weakens the heat transfer capacity. Moreover, the strong attractive interactions between PEC4 and Cu substrate will lead to the formation of oil film on the Cu surface during the evaporation and boiling processes, which will result in heat transfer deterioration.
Shouyin Cai; Chuang Wu; Xiaoxiao Li; Qibin Li. Effects of lubricant on evaporation and boiling processes of R1234ze(E): A molecular dynamics study. Applied Thermal Engineering 2021, 193, 117009 .
AMA StyleShouyin Cai, Chuang Wu, Xiaoxiao Li, Qibin Li. Effects of lubricant on evaporation and boiling processes of R1234ze(E): A molecular dynamics study. Applied Thermal Engineering. 2021; 193 ():117009.
Chicago/Turabian StyleShouyin Cai; Chuang Wu; Xiaoxiao Li; Qibin Li. 2021. "Effects of lubricant on evaporation and boiling processes of R1234ze(E): A molecular dynamics study." Applied Thermal Engineering 193, no. : 117009.
Pour point depressant is one of the effective approaches to improve the low temperature fluidity of high-wax crude oil. Understanding the gelation of waxy oil on the pipe wall and the mechanism of pour point depressant is of great significance for the transportation of crude oil. In this work, molecular dynamics simulations were employed to investigate the effects of ethylene-vinyl acetate (EVA) on the gelation of the waxy oil at different temperatures (283 K, 293 K, 303 K and 313 K) and to get insight into the wax deposition on a micro-level. The results showed that the network structures of wax crystals formed at the solid wall with temperature of 283 K, 293 K and 303 K, which caused the gelation of waxy crude oil. The wax crystals tended to be arranged horizontally near the wall and vertically away from the wall surface. Actually, the crystallization of wax molecules can not be prevented by EVA. However, the pour point of oil system was reduced by the EVA which prevented the wax crystal deposition and changed the shape of wax crystal.
Qibin Li; Xinxin Deng; Yang Liu; Qinglin Cheng; Chao Liu. Gelation of waxy crude oil system with ethylene-vinyl acetate on solid surface: A molecular dynamics study. Journal of Molecular Liquids 2021, 331, 115816 .
AMA StyleQibin Li, Xinxin Deng, Yang Liu, Qinglin Cheng, Chao Liu. Gelation of waxy crude oil system with ethylene-vinyl acetate on solid surface: A molecular dynamics study. Journal of Molecular Liquids. 2021; 331 ():115816.
Chicago/Turabian StyleQibin Li; Xinxin Deng; Yang Liu; Qinglin Cheng; Chao Liu. 2021. "Gelation of waxy crude oil system with ethylene-vinyl acetate on solid surface: A molecular dynamics study." Journal of Molecular Liquids 331, no. : 115816.
For ensuring the safe and stable operation of waxy crude oil pipeline transportation, in this research, the molecular dynamics model was established to characterize the deposition and wall sticking behavior of waxy crude oil multiphase system pipeline transportation. The equal density interpolation fitting method was proposed to determine the wall contact angle of simulation results. Through verification, the error between the simulation results and the experimental results measured by Dos Santos et al. (2006) was less than 5%, which showed that the established model was accurate and reliable. Using the established model, the deposition and wall sticking behavior of waxy crude oil nucleated clusters was simulated. It was found that the nucleated clusters would first adhere to the wall surface to form the solidified oil layer. Then, the wax and asphaltene molecules would diffuse to the deposit layer, and the oil molecules in the solidified oil layer reverse diffused to the direction of the oil flow. With the adhering and spreading degree of clusters on the wall surface increasing, the deposit layer gradually aged, and the gelled deposit layer with a higher density and hardness would form. On this basis, the micro influence mechanism of the surface free energy was studied. It was found that the higher the surface free energy, the more hydrophilic the pipeline wall was, and the higher the adhesion degree would be. Moreover, based on the ABF sampling and the potential of mean force calculations, the selective deposition process of waxy crude oil deposited on the sedimentary layer was studied. The micro information on the deposition sites, the binding conformation, and the binding energy of different molecules in clusters deposited on different molecules in sedimentary layer were analyzed. The investigations in this study could provide theoretical support for paraffin removal and control, which could ensure the safe and stable operation of the waxy crude oil production system.
Yifan Gan; Qinglin Cheng; Shengli Chu; Zhihua Wang; Guohua Luan; Wei Sun; Shuang Wang; Chao Liu; Qibin Li; Yang Liu. Molecular Dynamics Simulation of Waxy Crude Oil Multiphase System Depositing and Sticking on Pipeline Inner Walls and the Micro Influence Mechanism of Surface Physical–Chemical Characteristics. Energy & Fuels 2021, 35, 4012 -4028.
AMA StyleYifan Gan, Qinglin Cheng, Shengli Chu, Zhihua Wang, Guohua Luan, Wei Sun, Shuang Wang, Chao Liu, Qibin Li, Yang Liu. Molecular Dynamics Simulation of Waxy Crude Oil Multiphase System Depositing and Sticking on Pipeline Inner Walls and the Micro Influence Mechanism of Surface Physical–Chemical Characteristics. Energy & Fuels. 2021; 35 (5):4012-4028.
Chicago/Turabian StyleYifan Gan; Qinglin Cheng; Shengli Chu; Zhihua Wang; Guohua Luan; Wei Sun; Shuang Wang; Chao Liu; Qibin Li; Yang Liu. 2021. "Molecular Dynamics Simulation of Waxy Crude Oil Multiphase System Depositing and Sticking on Pipeline Inner Walls and the Micro Influence Mechanism of Surface Physical–Chemical Characteristics." Energy & Fuels 35, no. 5: 4012-4028.
The performances of multilayer Hex-star phosphorene (HP) for the CO2 removal from natural gas were investigated by molecular simulation combined with real adsorbed solution theory (RAST). The influences of pressure (0.01–3.0 MPa), molar fraction of CO2 in bulk gas (0.05, 0.1, 0.2, 0.3, 0.4) and pre-adsorbed water content (0.0–9.9 mmol g−1) in adsorbents were thoroughly discussed at 300 K. The adsorption isotherms of both CO2 and CH4 predicted by RAST agree well with the simulation data. The adsorption selectivity calculations indicate that the multilayer HP exhibits an excellent separation performance under high pressure and high CO2 concentration. Meanwhile, under the low CO2 concentration, resulting from the sieving effect and stronger interactions between CO2 and water molecules, the CO2 selectivity can be significantly improved without impact of CO2 loading by pre-adsorbing some water molecules in the multilayer HP. This work suggests that the HP can act as a promising material for natural gas purification.
Guangping Lei; Qibin Li; Hantao Liu; Yayun Zhang. Selective adsorption of CO2 by Hex-star phosphorene from natural gas: Combining molecular simulation and real adsorbed solution theory. Chemical Engineering Science 2020, 231, 116283 .
AMA StyleGuangping Lei, Qibin Li, Hantao Liu, Yayun Zhang. Selective adsorption of CO2 by Hex-star phosphorene from natural gas: Combining molecular simulation and real adsorbed solution theory. Chemical Engineering Science. 2020; 231 ():116283.
Chicago/Turabian StyleGuangping Lei; Qibin Li; Hantao Liu; Yayun Zhang. 2020. "Selective adsorption of CO2 by Hex-star phosphorene from natural gas: Combining molecular simulation and real adsorbed solution theory." Chemical Engineering Science 231, no. : 116283.
The organic flash cycle is an efficient low-grade energy conversion technology. However, a large space is left for the organic flash cycle to improve the useful energy output due to the throttling processes. To utilize the thermal energy before the low-pressure throttling process in the organic flash cycle driven by the geothermal energy, an ammonia-water absorption refrigeration cycle is adopted to generate cooling by using this part of heat, thereby forming a novel geothermal combined cooling and power (Geo-CCP) system. Eight different organic flash cycle working fluids are investigated, including n-Nonane, n-Octane, n-Heptane, Cyclopentane, i-Pentane, n-Pentane, R365mfc, and R245fa. Detailed thermodynamic modeling, thermoeconomic analysis, parametric analysis, system optimization, and exergy analysis are carried out for the proposed system. The results show that the total product unit cost and exergy efficiency of the proposed systems are 6.52–11.03% lower and 4.10–5.31%pt (percentage point) higher than those of the geothermal separate cooling and power systems. Among the eight considered organic fluids, the n-Nonane brings the lowest total product unit cost and highest exergy efficiency to the Geo-CCP system (11.20 $·GJ−1 and 37.58%). Exergy analysis indicates that the flasher and condenser-I have the first and second highest exergy destructions.
Chuang Wu; Xiaoxiao Xu; Qibin Li; Xiaoxiao Li; Lang Liu; Chao Liu. Performance assessment and optimization of a novel geothermal combined cooling and power system integrating an organic flash cycle with an ammonia-water absorption refrigeration cycle. Energy Conversion and Management 2020, 227, 113562 .
AMA StyleChuang Wu, Xiaoxiao Xu, Qibin Li, Xiaoxiao Li, Lang Liu, Chao Liu. Performance assessment and optimization of a novel geothermal combined cooling and power system integrating an organic flash cycle with an ammonia-water absorption refrigeration cycle. Energy Conversion and Management. 2020; 227 ():113562.
Chicago/Turabian StyleChuang Wu; Xiaoxiao Xu; Qibin Li; Xiaoxiao Li; Lang Liu; Chao Liu. 2020. "Performance assessment and optimization of a novel geothermal combined cooling and power system integrating an organic flash cycle with an ammonia-water absorption refrigeration cycle." Energy Conversion and Management 227, no. : 113562.
The phase transition of fluid on the solid surface plays an important role in engineering, while the mechanism of phase transition is still need to be studied in depth. Therefore, molecular dynamics simulations were employed to investigate the evaporation of different mole fraction of Ar/Kr mixtures on several wettability Pt substrates (weak hydrophobic surface, hydrophilic and weak hydrophobic mixed surface, hydrophilic and strong hydrophobic mixed surface, hydrophilic surface) at 200 K. The kinetic energy of fluid atoms and the interaction energy between Pt and fluid atoms were employed to understand the evaporation process. The vapor film boiling was observed in the systems with the mole fraction of Ar to be 100%, 75% and 50%. This leads to the heat flux significantly decreasing and heat transfer deterioration. The addition of Kr atoms will alleviate and prevent vapor film boiling of Ar atoms. Besides, the more the mole fraction of Kr in the system, the less possibility of Kr atoms can evaporate from the evaporation region. The strong hydrophobic surface would lead to the bubble generated earlier than weak hydrophobic surface. And the earlier generated bubble on hydrophilic and strong hydrophobic mixed surface will enhance the evaporation process than that on hydrophilic and weak hydrophobic mixed surface.
Shouyin Cai; Qibin Li; Wenjie Li; Lu Zhang; Xiangyang Liu. Effects of mole fraction and surface wettability on evaporation of Ar/Kr mixtures: A molecular dynamics study. Journal of Molecular Liquids 2020, 319, 114189 .
AMA StyleShouyin Cai, Qibin Li, Wenjie Li, Lu Zhang, Xiangyang Liu. Effects of mole fraction and surface wettability on evaporation of Ar/Kr mixtures: A molecular dynamics study. Journal of Molecular Liquids. 2020; 319 ():114189.
Chicago/Turabian StyleShouyin Cai; Qibin Li; Wenjie Li; Lu Zhang; Xiangyang Liu. 2020. "Effects of mole fraction and surface wettability on evaporation of Ar/Kr mixtures: A molecular dynamics study." Journal of Molecular Liquids 319, no. : 114189.
The evaporation of Ar/Kr mixtures on platinum surface at 150 K.
Shouyin Cai; Qibin Li; Chao Liu; Lu Zhang. Evaporation of Ar/Kr mixtures on platinum surface: a molecular dynamics study. Physical Chemistry Chemical Physics 2020, 22, 16157 -16164.
AMA StyleShouyin Cai, Qibin Li, Chao Liu, Lu Zhang. Evaporation of Ar/Kr mixtures on platinum surface: a molecular dynamics study. Physical Chemistry Chemical Physics. 2020; 22 (28):16157-16164.
Chicago/Turabian StyleShouyin Cai; Qibin Li; Chao Liu; Lu Zhang. 2020. "Evaporation of Ar/Kr mixtures on platinum surface: a molecular dynamics study." Physical Chemistry Chemical Physics 22, no. 28: 16157-16164.
Understanding the micro-mechanism of lignin gasification in supercritical water is meaningful for improving the energy conversion efficiency of biomass. In this work, the molecular model of guaiacyl dimer lignin with γ-O-4 linkages is built and the gasification processes of it in supercritical water at 9 different temperatures between 2000 K and 6000 K are studied by ReaxFF molecular dynamics simulations for the first time. The cleavage mechanism of γ-O-4 lignin and the generation pathways of gases were analyzed. During the gasification process of γ-O-4 lignin, H2 and CO are abundantly generated, while supercritical water contributes the most H and O molecules for them. Temperature are found to play important role in the products and rate of the cleavage of lignin.
Xiangyang Liu; Tao Wang; Jianchun Chu; Maogang He; Qibin Li; Ying Zhang. Understanding lignin gasification in supercritical water using reactive molecular dynamics simulations. Renewable Energy 2020, 161, 858 -866.
AMA StyleXiangyang Liu, Tao Wang, Jianchun Chu, Maogang He, Qibin Li, Ying Zhang. Understanding lignin gasification in supercritical water using reactive molecular dynamics simulations. Renewable Energy. 2020; 161 ():858-866.
Chicago/Turabian StyleXiangyang Liu; Tao Wang; Jianchun Chu; Maogang He; Qibin Li; Ying Zhang. 2020. "Understanding lignin gasification in supercritical water using reactive molecular dynamics simulations." Renewable Energy 161, no. : 858-866.
The utilization of renewable energy and waste heat recovery can effectively alleviate the ongoing energy crisis and environmental pollution. The organic Rankine cycle has been proven to be reliable in converting low-to-medium-grade waste heat to power. The fluid selection is a crucial factor in the organic Rankine cycle design procedure, because the cycle performance depends mainly on the thermophysical properties of the working fluid. In this study, the optimal selection principle, based on environmental and economic criteria, for 14 different working fluids is proposed, considering a heat-source temperature range of from 90 to 230 °C. Electricity production cost and reduction of greenhouse gas emissions were selected as the objective functions. Through carbon footprint analysis, the greenhouse gas emissions generated by the organic Rankine cycle were investigated. Then, parametric studies were performed to analyze the matching relationship between the heat-source temperatures and corresponding fluids. The results demonstrate that for organic Rankine cycles with low-global warming potential (GWP) fluids, the construction phase generates the majority of the total emissions, approximately 66.24–90.21%. For high-GWP fluids, such as R134a and R245fa, the majority of the emissions are generated during the operation phase and include approximately 481.17 tons and 374.47 tons CO2,eq, respectively. From the viewpoint of environmental benefits, R600a exhibited the highest emission reduction, approximately 9531.06 tons CO2,eq, followed by R152a, R600, and R245fa, at a heat-source temperature of 150 °C. The matching relationship study indicated that the optimal temperature ranges for R601 are 363–384 K and 481–503 K, based on the maximum emission reductions. Regarding the economic analysis, the suitable temperature range corresponding to the best economic performance for R245fa was 363–468 K. Finally, correlations based on the best environmental benefits between the heat-source temperatures and optimal fluids were provided.
Shukun Wang; Chao Liu; Qibin Li; Lang Liu; Erguang Huo; Cheng Zhang. Selection principle of working fluid for organic Rankine cycle based on environmental benefits and economic performance. Applied Thermal Engineering 2020, 178, 115598 .
AMA StyleShukun Wang, Chao Liu, Qibin Li, Lang Liu, Erguang Huo, Cheng Zhang. Selection principle of working fluid for organic Rankine cycle based on environmental benefits and economic performance. Applied Thermal Engineering. 2020; 178 ():115598.
Chicago/Turabian StyleShukun Wang; Chao Liu; Qibin Li; Lang Liu; Erguang Huo; Cheng Zhang. 2020. "Selection principle of working fluid for organic Rankine cycle based on environmental benefits and economic performance." Applied Thermal Engineering 178, no. : 115598.
Linxing Zhang; Qibin Li; Sen Tian; Guang Hong. Corrigendum to “Molecular Dynamics Simulation of the Cu/Au Nanoparticles Alloying Process”. Journal of Nanomaterials 2020, 2020, 1 -1.
AMA StyleLinxing Zhang, Qibin Li, Sen Tian, Guang Hong. Corrigendum to “Molecular Dynamics Simulation of the Cu/Au Nanoparticles Alloying Process”. Journal of Nanomaterials. 2020; 2020 ():1-1.
Chicago/Turabian StyleLinxing Zhang; Qibin Li; Sen Tian; Guang Hong. 2020. "Corrigendum to “Molecular Dynamics Simulation of the Cu/Au Nanoparticles Alloying Process”." Journal of Nanomaterials 2020, no. : 1-1.
Residential demand response is vital for the efficiency of power system. It has attracted much attention from both academic and industry in recent years. Accurate short-term load forecasting is a fundamental task for demand response. While short-term forecasting for aggregated load data has been extensively studied, load forecasting for individual residential users is still challenging due to the dynamic and stochastic characteristic of single users’ electricity consumption behaviors, i.e., the variability of the residential activities. To address this challenge, this paper presents a short-term residential load forecasting framework, which makes use of the spatio-temporal correlation existing in appliances’ load data through deep learning. Multiple time series are conducted in the framework to describe electricity consumption behaviors and their internal spatio-temporal relationship. And a method based on deep neural network and iterative ResBlock is proposed to learn the correlation among different electricity consumption behaviors for short-term load forecasting. Experiments based on real world measurements have been conducted to evaluate the performance of the proposed forecasting approach. The results show that both the appliances’ load data and iterative ResBlocks can help to improve the forecasting performance. Compared with existing methods, measurements on Root Mean Squared Error, Mean Absolute Error and Mean Absolute Percentage Error for the proposed approach are reduced by 3.89%-20.00%, 2.18%-22.58% and 0.69%-32.78%. In addition, further experiments are conducted to evaluate the impact of using appliances' load data, iterative ResBlocks as well as other factors for the proposed approach.
Ye Hong; Yingjie Zhou; Qibin Li; Wenzheng Xu; Xiujuan Zheng. A Deep Learning Method for Short-Term Residential Load Forecasting in Smart Grid. IEEE Access 2020, 8, 55785 -55797.
AMA StyleYe Hong, Yingjie Zhou, Qibin Li, Wenzheng Xu, Xiujuan Zheng. A Deep Learning Method for Short-Term Residential Load Forecasting in Smart Grid. IEEE Access. 2020; 8 (99):55785-55797.
Chicago/Turabian StyleYe Hong; Yingjie Zhou; Qibin Li; Wenzheng Xu; Xiujuan Zheng. 2020. "A Deep Learning Method for Short-Term Residential Load Forecasting in Smart Grid." IEEE Access 8, no. 99: 55785-55797.
The ionic liquids have great potential in the field of energy and power engineering for their thermophysical properties can be modified by changing the types of anion and cation. In this paper, molecular dynamics simulations are employed to investigate the molecular characteristics of 1-Butyl-3-methyl tetra-fluoroborate [BMIM][BF4] ionic liquid and its blends with water on the Pt surface. The results show that the number of [BMIM][BF4] ionic liquid near Pt surface slightly decreases with the molar ratio of water molecules increasing. And mobility of anions and cations of [BMIM][BF4] ionic liquid are strengthened by the addition of water. Additionally, the thermal conductivity and viscosity of [BMIM][BF4] ionic liquid are weakened with water blended. A hypothesis that water replacing the [BF4]− to form the hydrogen bond with [BMIM]+ is proposed to explain the weakening of viscosity of the mixture system. And the Pt surface will strengthen the viscosity and thermal conductivity of [BMIM][BF4]/water mixtures in the vertical direction of the substrate.
Shouyin Cai; Qibin Li; Maoxiang Li; Chao Liu. Molecular characteristics of [BMIM][BF4] ionic liquids and water mixtures on the Pt surface. Journal of Molecular Liquids 2020, 304, 112782 .
AMA StyleShouyin Cai, Qibin Li, Maoxiang Li, Chao Liu. Molecular characteristics of [BMIM][BF4] ionic liquids and water mixtures on the Pt surface. Journal of Molecular Liquids. 2020; 304 ():112782.
Chicago/Turabian StyleShouyin Cai; Qibin Li; Maoxiang Li; Chao Liu. 2020. "Molecular characteristics of [BMIM][BF4] ionic liquids and water mixtures on the Pt surface." Journal of Molecular Liquids 304, no. : 112782.
The refrigerants mixture has a great perspective in the thermal engineering, while the evaporation of refrigerants mixture still needs to be studied in depth. Therefore, molecular dynamics simulations were employed to investigate the evaporation process of the following refrigerants, pure refrigerant R32, R152a and R32/R152a mixtures (with mole ratio of 1:1, 3:1, and 1:3), on the Pt surface at 220 K, 250 K and 350 K, respectively. The results showed that R32 is more likely to evaporate than R152a in the simulated systems under the same conditions. The Pt substrate absorbs more R32 molecules than R152a molecules. Besides, the nucleate boiling and film boiling are found in the systems evaporating at 350 K. The results also suggest that the existence of R152a molecules will alleviate the boiling of R32 molecules, owing to the higher boiling point of R152a and the weaker adsorption capacity of R152a on the Pt surface. And the R32/R152a mixture systems own better cooling capacity than that of pure R32 and pure R152a systems.
Shouyin Cai; Qibin Li; Chao Liu; Yingjie Zhou. Evaporation of R32/R152a mixtures on the Pt surface: A molecular dynamics study. International Journal of Refrigeration 2020, 113, 156 -163.
AMA StyleShouyin Cai, Qibin Li, Chao Liu, Yingjie Zhou. Evaporation of R32/R152a mixtures on the Pt surface: A molecular dynamics study. International Journal of Refrigeration. 2020; 113 ():156-163.
Chicago/Turabian StyleShouyin Cai; Qibin Li; Chao Liu; Yingjie Zhou. 2020. "Evaporation of R32/R152a mixtures on the Pt surface: A molecular dynamics study." International Journal of Refrigeration 113, no. : 156-163.
Shale gas is a multicomponent mixtures stored in nanoporous, which consists mainly of methane (CH4) and ethane (C2H6). The transport property of shale gas in clay nanoporous is a fundamental issue not only for accelerating exploitation of shale gas, but also for grasping the diffusivity mechanism of gas mixture in nanostructures. In this work, the transport property of CH4 and C2H6 in K-illite nanoporous of shale is investigated by molecule dynamics combined with the Fick’s First Law. The equilibrium molecular dynamics (EMD) is utilized to calculate the binary Onsager coefficients. Thermodynamics factor, the Self-, Maxwell-Stefan (MS) and transport diffusion coefficient of CH4-C2H6 is estimated and the effects of pressure, temperature and apertures are analyzed. The results show that the diffusion of gas in the confined space is satisfied with the linear law. The self-diffusion coefficient of CH4 is greater than that of C2H6, owing to the surface diffusivity of C2H6 is lower than that of CH4. The MS and transport diffusion coefficient of CH4 is lower than that of C2H6. High pressure can inhibit the diffusivity of alkanes. The larger aperture and higher temperature can enhance the diffusivity property. The reduction rate of transport diffusion selectivity for C2H6 over CH4 decreases with the increasing aperture width. With the increasing width of apertures, C2H6 has a better diffusivity owing to the interaction of gas molecule and wall surface. The competitive diffusion of C2H6 and CH4 is more sensitive to the formation conditions of temperature and pressure and the transport selectivity of C2H6 over CH4 can be used to assess the diffusivity capacity between binary mixture gases in nanoporous. It is expected that this work can accommodate the secure and efficient exploitation of shale gas in nanoporous with significant insights and quantitative predictions regarding the formation conditions of temperature and pressure.
Lu Zhang; Chao Liu; Yang Liu; Qibin Li; Qinglin Cheng; Shouyin Cai. Transport Property of Methane and Ethane in K-Illite Nanopores of Shale: Insights from Molecular Dynamic Simulations. Energy & Fuels 2020, 34, 1710 -1719.
AMA StyleLu Zhang, Chao Liu, Yang Liu, Qibin Li, Qinglin Cheng, Shouyin Cai. Transport Property of Methane and Ethane in K-Illite Nanopores of Shale: Insights from Molecular Dynamic Simulations. Energy & Fuels. 2020; 34 (2):1710-1719.
Chicago/Turabian StyleLu Zhang; Chao Liu; Yang Liu; Qibin Li; Qinglin Cheng; Shouyin Cai. 2020. "Transport Property of Methane and Ethane in K-Illite Nanopores of Shale: Insights from Molecular Dynamic Simulations." Energy & Fuels 34, no. 2: 1710-1719.
This paper proposes a novel combined cooling and power (CCP) system based on a regenerative supercritical carbon dioxide Brayton cycle (sCO2 cycle) and an ammonia-water absorption refrigeration cycle (ARC) for engine waste heat recovery. In the proposed system, the supercritical carbon dioxide Brayton cycle absorbs the waste heat of the internal combustion engine to generate power, and the absorption refrigeration cycle utilizes the low-grade energy in the supercritical carbon dioxide turbine exhaust to provide cooling. Firstly, energy and exergy analysis is performed on the combined cooling and power system. Then, detailed parametric analysis is carried out to study the effects of key parameters, such as the compressor outlet pressure, turbine inlet temperature, generator hot-end temperature difference, and evaporator temperature on the exergy efficiency and total product unit cost. Finally, the non-dominated sorting genetic algorithm II is adopted for multi-objective optimization to obtain the maximum exergy efficiency and the minimum total product unit cost. Multi-objective optimization results reveal that better thermodynamic and economic performances can be obtained by lowering the evaporator temperature. Compared with the single regenerative supercritical carbon dioxide system, the proposed system can increase the exergy efficiency by 2.29–2.54%pt (percentage point), and the thermal efficiency by 8.16–18.93%pt, but might increase the total product unit cost. Under different evaporator temperatures (−10–10 °C), the proposed system can generate 248.19–253.90 kW of net power output, accounting for 8.48–8.67% of the rated power output of the engine, and produce 70.57–168.86 kW of cooling capacity by consuming 0.445–0.532 kW of pump work. In addition, exergy destruction analyses indicate that the components in the bottoming ARC generally have less exergy destructions.
Chuang Wu; Xiaoxiao Xu; Qibin Li; Jun Li; Shunsen Wang; Chao Liu. Proposal and assessment of a combined cooling and power system based on the regenerative supercritical carbon dioxide Brayton cycle integrated with an absorption refrigeration cycle for engine waste heat recovery. Energy Conversion and Management 2020, 207, 112527 .
AMA StyleChuang Wu, Xiaoxiao Xu, Qibin Li, Jun Li, Shunsen Wang, Chao Liu. Proposal and assessment of a combined cooling and power system based on the regenerative supercritical carbon dioxide Brayton cycle integrated with an absorption refrigeration cycle for engine waste heat recovery. Energy Conversion and Management. 2020; 207 ():112527.
Chicago/Turabian StyleChuang Wu; Xiaoxiao Xu; Qibin Li; Jun Li; Shunsen Wang; Chao Liu. 2020. "Proposal and assessment of a combined cooling and power system based on the regenerative supercritical carbon dioxide Brayton cycle integrated with an absorption refrigeration cycle for engine waste heat recovery." Energy Conversion and Management 207, no. : 112527.
The heat capacity of working fluid can be enhanced through the mutual transformation between thermal energy and surface energy during the absorption and separation process of fluid molecules in porous materials. In this paper, molecular simulation (molecular dynamics and grand canonical Monte Carlo) methods were used to study the absorption and energy storage properties of R1234yf, R1234ze(z), R32 and their mixtures in Co-MOF-74. In order to evaluate the properties of thermal energy storage of metal organic heat carriers (MOHCs), the enthalpy difference (ΔhMOHCs) of MOHCs was calculated. ΔhMOHCs consists of the enthalpy of pure organic fluid (∆hFluid), the energy change of metal organic framework (MOF) nanoparticles ((∫c
Qibin Li; Shouyin Cai; Chao Liu. Molecular simulation of energy storage of R1234yf, R1234ze(z), R32, and their mixtures in Co-MOF-74 materials. Chinese Science Bulletin 2019, 65, 633 -640.
AMA StyleQibin Li, Shouyin Cai, Chao Liu. Molecular simulation of energy storage of R1234yf, R1234ze(z), R32, and their mixtures in Co-MOF-74 materials. Chinese Science Bulletin. 2019; 65 (7):633-640.
Chicago/Turabian StyleQibin Li; Shouyin Cai; Chao Liu. 2019. "Molecular simulation of energy storage of R1234yf, R1234ze(z), R32, and their mixtures in Co-MOF-74 materials." Chinese Science Bulletin 65, no. 7: 633-640.
The adsorption of hydrogen sulfide in gas reservoir cores is important to natural gas industry for predicting the sulfur content. Here, the adsorption of hydrogen sulfide in the calcite pore is investigated using molecular simulations. The results show that the absolute adsorption amount of H2S increases with the increasing of the pressure. However, the absolute adsorption amount decreases with the increasing of temperature. The adsorption capacity of H2S on the calcite surface can be well described by the combination of Langmuir equation and Clausius-Clapeyron equation. In order to investigate the effect of hydrogen bond on adsorption, a method of computing the hydrogen bond of H2S is proposed. The number of the average hydrogen bond per H2S molecules increases with the increasing of pressure. Furthermore, the existence of calcite surface will affect the distribution of hydrogen bond. This will order the structures of H2S molecules near the calcite surface and break the hydrogen bonds.
Shouyin Cai; Qibin Li; Chao Liu; Xiangyang Liu. The adsorption of hydrogen sulfide in calcite pores: A molecular simulation study. Journal of Molecular Liquids 2019, 299, 112253 .
AMA StyleShouyin Cai, Qibin Li, Chao Liu, Xiangyang Liu. The adsorption of hydrogen sulfide in calcite pores: A molecular simulation study. Journal of Molecular Liquids. 2019; 299 ():112253.
Chicago/Turabian StyleShouyin Cai; Qibin Li; Chao Liu; Xiangyang Liu. 2019. "The adsorption of hydrogen sulfide in calcite pores: A molecular simulation study." Journal of Molecular Liquids 299, no. : 112253.
As a prominent technology for recovering low-grade waste heat, supercritical organic Rankine cycle (ORC) exhibits a better performance due to the higher endothermic temperature and better thermal match with the heat source. The irreversibility in system can be reduced greatly when the zeotropic mixtures are used as working fluid to match the heat source and sink profiles. Affected by the fluctuations in waste heat sources, there is a challenge for ORC to recovery waste heat. An improved dynamic model of supercritical ORC using zeotropic mixture R134a/R32 as working fluid is developed and dynamic behaviors of supercritical ORC are analyzed. It is found that an abnormal fluctuation may occur in some parameters due to the effects around pseudo-critical point and thermal inertia of the heater. A fitting correlation to predict the response time based on different heat transfer coefficients of heater is found. Besides, three dynamic regimes are defined to investigate the effects of heat source frequencies and system thermal inertia on the dynamic response. As the heat source frequency increases or the heat exchange in the heater is enhanced, the fluctuation amplitude of the pressure decreases in the heater.
Xiaoxue Chen; Chao Liu; Qibin Li; Xurong Wang; Shukun Wang. Dynamic behavior of supercritical organic Rankine cycle using zeotropic mixture working fluids. Energy 2019, 191, 116576 .
AMA StyleXiaoxue Chen, Chao Liu, Qibin Li, Xurong Wang, Shukun Wang. Dynamic behavior of supercritical organic Rankine cycle using zeotropic mixture working fluids. Energy. 2019; 191 ():116576.
Chicago/Turabian StyleXiaoxue Chen; Chao Liu; Qibin Li; Xurong Wang; Shukun Wang. 2019. "Dynamic behavior of supercritical organic Rankine cycle using zeotropic mixture working fluids." Energy 191, no. : 116576.
Sintering is an important approach for the alloying of different metals, which is affected by factors such as temperature, grain size, and material properties. And it represents a complex thermodynamic process. This paper had adopted the molecular dynamics methods to investigate the evolution process of nanostructure during the sintering of Cu and Au nanoparticles. The changes in crystalline during the nanosintering process were observed, and the radial distribution function of atoms, the shrinkage ratio, and the sintering neck of the systems were discussed. The initial sintering temperature and melting temperature of the system were obtained; at the same time, the characteristics of the sintering neck with changes in temperature during the nanosintering process were revealed.
Linxing Zhang; Qibin Li; Sen Tian; Guang Hong. Molecular Dynamics Simulation of the Cu/Au Nanoparticle Alloying Process. Journal of Nanomaterials 2019, 2019, 1 -7.
AMA StyleLinxing Zhang, Qibin Li, Sen Tian, Guang Hong. Molecular Dynamics Simulation of the Cu/Au Nanoparticle Alloying Process. Journal of Nanomaterials. 2019; 2019 ():1-7.
Chicago/Turabian StyleLinxing Zhang; Qibin Li; Sen Tian; Guang Hong. 2019. "Molecular Dynamics Simulation of the Cu/Au Nanoparticle Alloying Process." Journal of Nanomaterials 2019, no. : 1-7.