Daoping LIU - Academia.edu (original) (raw)
Papers by Daoping LIU
SSRN Electronic Journal, 2021
CO2 hydrate slurry, a kind of two-phase fluid, is made of CO2 hydrate particles suspended in liqu... more CO2 hydrate slurry, a kind of two-phase fluid, is made of CO2 hydrate particles suspended in liquid water. It is considered as a good candidate in cool storage or secondary refrigerant due to its high latent heat for phase change. In this paper, the state of art of CO2 hydrate slurry research is reviewed, the main focuses include its characteristics of the formation dynamics, and its characteristics of flow and heat transfer. Meanwhile, a novel apparatus is introduced to continuously produce CO2 hydrate slurry for cool storage application. Challenges in the technology are discussed and measures of promoting the application of CO2 hydrate slurry in cool storage are suggested.
Journal of Molecular Liquids, 2021
Abstract Understanding and controlling the growth of CO2 hydrates is critical for a variety of in... more Abstract Understanding and controlling the growth of CO2 hydrates is critical for a variety of industrial applications, such as sequestration of greenhouse gases. Due to the excellent physical and chemical properties, metal nanoclusters are widely used as additives in hydrate experiments. However, little is known about the molecular mechanism of this process. In this study, molecular dynamics (MD) simulation was performed at 260 K and 30 MPa by adding different types of metal particles (Cu, Fe and Ag) and different mass fractions (0.2 wt%, 0.5 wt%, 0.8 wt%, 1.0 wt% and 1.3 wt%) to study the growth kinetics of the CO2 hydrate system containing pre-placed hydrate crystal cells. Simulation results showed that the presence of these metal particles has a mixed effect on the growth kinetics, and the extent of the effect seems to varies with different additives and also with the concentration of the metal particles used. It was observed that Cu particles had the most obvious promoting effect on hydrate growth. When the mass fraction of Cu particles was between 0.2 wt% and 1.0 wt%, the rate of hydrate formation increased, especially at the mass fraction of 1.0 wt%. The growth rate of CO2 hydrate was almost 50% higher than that of pure water system at this concentration. In addition, Fe particles had a medium effect on promoting CO2 hydrate growth. Ag particles had no obvious effect on CO2 hydrate growth. Results show that the addition of metal particles with high specific surface areas greatly increases the mass and heat transfer among the gas, liquid and hydrate phases, which is conducive to the growth of CO2 hydrate.
Environmental Engineering and Management Journal, 2011
Journal of Molecular Liquids, 2020
Chinese Journal of Chemical Engineering, 2019
Applied Catalysis B: Environmental, 2019
Nanoscale, 2019
The grand challenge leading to use of electrocatalysts is the degradation of active species which... more The grand challenge leading to use of electrocatalysts is the degradation of active species which results in poor durability and long-term performances. Studying the origin of active metal particle stabilization...
Chemical Engineering Journal, 2019
Abstract A gelatinous dry solution (GDS) was prepared by blending sodium dodecyl sulfate solution... more Abstract A gelatinous dry solution (GDS) was prepared by blending sodium dodecyl sulfate solution, gellan gum powder, and hydrophobic silica nanoparticles in air at a high speed. It is essentially a pile of free-flowing micro surfactant droplets supported by a gelling agent. The GDS has the dispersion characteristics of dry water, activity of the surfactant solution and stability of the gel. The flour-like droplets can provide abundant micro channels for gas transfer, a considerable surface area for gas–liquid contact and stable gel-like structure for repeated hydrate formation. Multi-cycle methane consumption experiments were conducted in a stainless steel vessel at 5.0–8.1 MPa and 273.2 K, in order to study the repeated kinetics of methane hydrate formation in GDS. The results demonstrated that the dispersed GDS facilitated rapid and reversible methane storage in clathrate hydrate by enhancing the gas–liquid contact and the stability of the regular droplets. Methane uptake (152.2–163.2 m3·m−3) and maximum uptake rates (4.522–5.690 m3·m−3·min−1) were achieved in the first storage cycle at the experimental pressures. GDS maintained relatively high methane storage capacities (114.3–118.0 m3·m−3) until the ninth cycle, and the capacities only were attenuated by 24.92–27.70% with respect to the first cycle at the above pressures. A hypothesis of “droplets breakage by released gas” was proposed to illustrate the attenuation of gas storage capacity of the droplets.
Applied Thermal Engineering, 2017
Investigated the structure of bubble pump to solve the problems of low efficiency. A bubble pum... more Investigated the structure of bubble pump to solve the problems of low efficiency. A bubble pump with variable cross-section lift tube (BPVC) was proposed. The lifting performance of BPVC was studied. BPVC had better working characteristics when the heating power was 200~500W.
Applied Thermal Engineering, 2016
The cone-mouthed multiple lift-tube bubble pump has a good ability in lifting working fluid. The ... more The cone-mouthed multiple lift-tube bubble pump has a good ability in lifting working fluid. The ideal flow regime for the experiments is basically slug flow. Pumping effectiveness could be as high as 13.89% with additional risers. Increasing the number of riser will not result in lifting capacity and efficiency in direct proportion.
Chemical Engineering Science, 2016
Challenges of Power Engineering and Environment, 2007
ABSTRACT Natural gas hydrates can be formed and stored at much more moderate thermodynamic condit... more ABSTRACT Natural gas hydrates can be formed and stored at much more moderate thermodynamic conditions compared to conventional gas storage media that make it as a new means of transportation and storage for natural gas. In this work, an experimental investigation of natural gas hydrate formation has been conducted in a high-pressure water-spraying reactor, which is cooled by the circulation water through an external cooling jacket. The process of hydrate formation can be observed visually through a pair of glass windows and recorded by a digital video. The characteristics of gas hydrate formation by water spraying under different conditions were determined by the development of pressure combined with temperature. The results showed that the induction time of hydrate formation can be greatly shortened by water spraying. Solution with appropriate surfactant SDS was found to increase the formation rate obviously and the mechanism was discussed.
2010 14th International Heat Transfer Conference, Volume 2, 2010
Gas hydrates are solid, crystalline, ice-like compounds composed of water and guest molecules. Th... more Gas hydrates are solid, crystalline, ice-like compounds composed of water and guest molecules. The formation of gas hydrates is a complex process with heat and mass transfer in gas, liquid and solid. Increasing the hydrates formation rate and the storage capacity, reducing hydrate induction time are main technical barriers for the application of gas hydrate. A one-dimensional numerical model of heat transfer during gas hydrate film formation on gas-liquid interface is investigated by analyzing the process of static system. According to the rate of gas consumed, the relation between the thickness of hydrate film and time can be obtained. The temperature distribution of different phase in the system is analyzed and the effect of temperature distribution of water is confirmed. The result indicates that it is effective to accelerate the rate of hydrate formation by enhancing the heat transfer in water phase.
Advanced Materials Research, 2012
A one-dimensional mathematical model of mass transfer during CO2 gas hydrate film formation at th... more A one-dimensional mathematical model of mass transfer during CO2 gas hydrate film formation at the boundary between the gas and water is established by analyzing the process of the static system. According to the model, we can get the concentration distribution of free CO2 in the hydrate film along with the time, and the conversion rate of hydrate with time can also be obtained. The results calculated at specific experiment condition in the system are analyzed. It indicates that the conversion rate can reach about 85% after 10 hours under static condition with 3.5MPa pressure and 0.5°C temperature by pure water when the initial reaction liquid depth is 20 mm
Journal of Thermal Analysis and Calorimetry, 2010
Energy Conversion and Management, 2011
SSRN Electronic Journal, 2021
CO2 hydrate slurry, a kind of two-phase fluid, is made of CO2 hydrate particles suspended in liqu... more CO2 hydrate slurry, a kind of two-phase fluid, is made of CO2 hydrate particles suspended in liquid water. It is considered as a good candidate in cool storage or secondary refrigerant due to its high latent heat for phase change. In this paper, the state of art of CO2 hydrate slurry research is reviewed, the main focuses include its characteristics of the formation dynamics, and its characteristics of flow and heat transfer. Meanwhile, a novel apparatus is introduced to continuously produce CO2 hydrate slurry for cool storage application. Challenges in the technology are discussed and measures of promoting the application of CO2 hydrate slurry in cool storage are suggested.
Journal of Molecular Liquids, 2021
Abstract Understanding and controlling the growth of CO2 hydrates is critical for a variety of in... more Abstract Understanding and controlling the growth of CO2 hydrates is critical for a variety of industrial applications, such as sequestration of greenhouse gases. Due to the excellent physical and chemical properties, metal nanoclusters are widely used as additives in hydrate experiments. However, little is known about the molecular mechanism of this process. In this study, molecular dynamics (MD) simulation was performed at 260 K and 30 MPa by adding different types of metal particles (Cu, Fe and Ag) and different mass fractions (0.2 wt%, 0.5 wt%, 0.8 wt%, 1.0 wt% and 1.3 wt%) to study the growth kinetics of the CO2 hydrate system containing pre-placed hydrate crystal cells. Simulation results showed that the presence of these metal particles has a mixed effect on the growth kinetics, and the extent of the effect seems to varies with different additives and also with the concentration of the metal particles used. It was observed that Cu particles had the most obvious promoting effect on hydrate growth. When the mass fraction of Cu particles was between 0.2 wt% and 1.0 wt%, the rate of hydrate formation increased, especially at the mass fraction of 1.0 wt%. The growth rate of CO2 hydrate was almost 50% higher than that of pure water system at this concentration. In addition, Fe particles had a medium effect on promoting CO2 hydrate growth. Ag particles had no obvious effect on CO2 hydrate growth. Results show that the addition of metal particles with high specific surface areas greatly increases the mass and heat transfer among the gas, liquid and hydrate phases, which is conducive to the growth of CO2 hydrate.
Environmental Engineering and Management Journal, 2011
Journal of Molecular Liquids, 2020
Chinese Journal of Chemical Engineering, 2019
Applied Catalysis B: Environmental, 2019
Nanoscale, 2019
The grand challenge leading to use of electrocatalysts is the degradation of active species which... more The grand challenge leading to use of electrocatalysts is the degradation of active species which results in poor durability and long-term performances. Studying the origin of active metal particle stabilization...
Chemical Engineering Journal, 2019
Abstract A gelatinous dry solution (GDS) was prepared by blending sodium dodecyl sulfate solution... more Abstract A gelatinous dry solution (GDS) was prepared by blending sodium dodecyl sulfate solution, gellan gum powder, and hydrophobic silica nanoparticles in air at a high speed. It is essentially a pile of free-flowing micro surfactant droplets supported by a gelling agent. The GDS has the dispersion characteristics of dry water, activity of the surfactant solution and stability of the gel. The flour-like droplets can provide abundant micro channels for gas transfer, a considerable surface area for gas–liquid contact and stable gel-like structure for repeated hydrate formation. Multi-cycle methane consumption experiments were conducted in a stainless steel vessel at 5.0–8.1 MPa and 273.2 K, in order to study the repeated kinetics of methane hydrate formation in GDS. The results demonstrated that the dispersed GDS facilitated rapid and reversible methane storage in clathrate hydrate by enhancing the gas–liquid contact and the stability of the regular droplets. Methane uptake (152.2–163.2 m3·m−3) and maximum uptake rates (4.522–5.690 m3·m−3·min−1) were achieved in the first storage cycle at the experimental pressures. GDS maintained relatively high methane storage capacities (114.3–118.0 m3·m−3) until the ninth cycle, and the capacities only were attenuated by 24.92–27.70% with respect to the first cycle at the above pressures. A hypothesis of “droplets breakage by released gas” was proposed to illustrate the attenuation of gas storage capacity of the droplets.
Applied Thermal Engineering, 2017
Investigated the structure of bubble pump to solve the problems of low efficiency. A bubble pum... more Investigated the structure of bubble pump to solve the problems of low efficiency. A bubble pump with variable cross-section lift tube (BPVC) was proposed. The lifting performance of BPVC was studied. BPVC had better working characteristics when the heating power was 200~500W.
Applied Thermal Engineering, 2016
The cone-mouthed multiple lift-tube bubble pump has a good ability in lifting working fluid. The ... more The cone-mouthed multiple lift-tube bubble pump has a good ability in lifting working fluid. The ideal flow regime for the experiments is basically slug flow. Pumping effectiveness could be as high as 13.89% with additional risers. Increasing the number of riser will not result in lifting capacity and efficiency in direct proportion.
Chemical Engineering Science, 2016
Challenges of Power Engineering and Environment, 2007
ABSTRACT Natural gas hydrates can be formed and stored at much more moderate thermodynamic condit... more ABSTRACT Natural gas hydrates can be formed and stored at much more moderate thermodynamic conditions compared to conventional gas storage media that make it as a new means of transportation and storage for natural gas. In this work, an experimental investigation of natural gas hydrate formation has been conducted in a high-pressure water-spraying reactor, which is cooled by the circulation water through an external cooling jacket. The process of hydrate formation can be observed visually through a pair of glass windows and recorded by a digital video. The characteristics of gas hydrate formation by water spraying under different conditions were determined by the development of pressure combined with temperature. The results showed that the induction time of hydrate formation can be greatly shortened by water spraying. Solution with appropriate surfactant SDS was found to increase the formation rate obviously and the mechanism was discussed.
2010 14th International Heat Transfer Conference, Volume 2, 2010
Gas hydrates are solid, crystalline, ice-like compounds composed of water and guest molecules. Th... more Gas hydrates are solid, crystalline, ice-like compounds composed of water and guest molecules. The formation of gas hydrates is a complex process with heat and mass transfer in gas, liquid and solid. Increasing the hydrates formation rate and the storage capacity, reducing hydrate induction time are main technical barriers for the application of gas hydrate. A one-dimensional numerical model of heat transfer during gas hydrate film formation on gas-liquid interface is investigated by analyzing the process of static system. According to the rate of gas consumed, the relation between the thickness of hydrate film and time can be obtained. The temperature distribution of different phase in the system is analyzed and the effect of temperature distribution of water is confirmed. The result indicates that it is effective to accelerate the rate of hydrate formation by enhancing the heat transfer in water phase.
Advanced Materials Research, 2012
A one-dimensional mathematical model of mass transfer during CO2 gas hydrate film formation at th... more A one-dimensional mathematical model of mass transfer during CO2 gas hydrate film formation at the boundary between the gas and water is established by analyzing the process of the static system. According to the model, we can get the concentration distribution of free CO2 in the hydrate film along with the time, and the conversion rate of hydrate with time can also be obtained. The results calculated at specific experiment condition in the system are analyzed. It indicates that the conversion rate can reach about 85% after 10 hours under static condition with 3.5MPa pressure and 0.5°C temperature by pure water when the initial reaction liquid depth is 20 mm
Journal of Thermal Analysis and Calorimetry, 2010
Energy Conversion and Management, 2011