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Zhao, Ruikai
Publications (3 of 3) Show all publications
Yue, Z., Li, Z., Shuai, D., Zhao, R., Xianhua, N. & Yinan, L. (2019). Effect of Nanobubble Evolution on Hydrate Process: A Review. JOURNAL OF THERMAL SCIENCE, 28(5), 948-961
Open this publication in new window or tab >>Effect of Nanobubble Evolution on Hydrate Process: A Review
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2019 (English)In: JOURNAL OF THERMAL SCIENCE, ISSN 1003-2169, Vol. 28, no 5, p. 948-961Article, review/survey (Refereed) Published
Abstract [en]

As a huge reserve for potential energy, natural gas hydrates (NGHs) are attracting increasingly extra attentions, and a series of researches on gas recovery from NGHs sediments have been carried out. But the slow formation and dissociation kinetics of NGHs is a major bottleneck in the applications of NGHs technology. Previous studies have shown that nanobubbles, which formed from melt hydrates, have significant promotion effects on dissociation and reformation dynamics of gas hydrates. Nanobubbles can persist for a long time in liquids, disaccording with the standpoint of classical thermodynamic theories, thus they can participate in the hydrate process. Based on different types of hydrate systems (gas + water, gas +water +inhibitors/promoters, gas + water + hydrophilic/hydrophobic surface), the effects of nanobubble evolution on nucleation, dissociation, reformation process and "memory effect" of gas hydrates are discussed in this paper. Researches on the nanobubbles in hydrate process are also summarized and prospected in this study.

Place, publisher, year, edition, pages
SPRINGER, 2019
Keywords
gas hydrates, nanobubbles, memory effect, hydrate process, RIJK SE, 1994, WATER RESEARCH, V28, P465
National Category
Energy Systems
Identifiers
urn:nbn:se:kth:diva-260163 (URN)10.1007/s11630-019-1181-x (DOI)000483700900010 ()2-s2.0-85069934365 (Scopus ID)
Note

QC 20190927

Available from: 2019-09-27 Created: 2019-09-27 Last updated: 2019-09-27Bibliographically approved
Li, S., Deng, S., Zhao, R., Zhao, L., Xu, W., Yuan, X. & Guo, Z. (2019). Entropy analysis on energy-consumption process and improvement method of temperature/vacuum swing adsorption (TVSA) cycle. Energy, 179, 876-889
Open this publication in new window or tab >>Entropy analysis on energy-consumption process and improvement method of temperature/vacuum swing adsorption (TVSA) cycle
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2019 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 179, p. 876-889Article in journal (Refereed) Published
Abstract [en]

CO2 adsorption capture, which could be driven by various forms of energy, has been widely studied in recent years due to the equipment is easy to control with low energy consumption required. However, the existing research on the energy-efficiency aspects of temperature/vacuum swing adsorption (TVSA) for CO2 capture are primarily focus on the quantification of input energy in specific cases. As a classical concept in thermodynamics, entropy has been widely applied in researches on the energy conversion process, which could benefit an in-depth understanding on the mechanism of "heatgeneralized chemical energy" conversion. However, an integrated thermodynamic research framework, which could clarify how to conduct a reasonable energy-consumption analysis of TVSA, has not been established yet. In this paper, a simplified thermodynamic cycle of 4-step TVSA was established, with the assumption of CO2 in adsorbed phase as loop fluid. With the application of the thermodynamic research framework proposed in this paper, the entropy analysis on the thermodynamic cycle was conducted. This study is concerned with application of thermodynamics concept to the CO2 adsorption engineering, which is mainly based on classical thermodynamics but also relying on adsorption physics to supply insight into the energy conversion and energy-efficient mechanism of TVSA technologies.

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2019
Keywords
CO2 capture, Adsorption, Carbon pump cycle, Entropy generation, Heat recovery
National Category
Energy Systems
Identifiers
urn:nbn:se:kth:diva-255407 (URN)10.1016/j.energy.2019.05.027 (DOI)000472813800075 ()
Note

QC 20190814

Available from: 2019-08-14 Created: 2019-08-14 Last updated: 2019-08-14Bibliographically approved
Zhao, R., Liu, L., Zhao, L., Deng, S., Li, S., Zhang, Y. & Li, H. (2019). Thermodynamic exploration of temperature vacuum swing adsorption for direct air capture of carbon dioxide in buildings. Energy Conversion and Management, 183, 418-426
Open this publication in new window or tab >>Thermodynamic exploration of temperature vacuum swing adsorption for direct air capture of carbon dioxide in buildings
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2019 (English)In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 183, p. 418-426Article in journal (Refereed) Published
Abstract [en]

Abrupt climate change such as the loss of Arctic sea-ice area urgently needs negative emissions technologies. The potential application of direct air capture of carbon dioxide from indoor air and outdoor air in closed buildings or crowded places has been discussed in this paper. From the aspects of carbon reduction and indoor comfort, the ventilation system integrating a capture device is of great value in practical use. For ultra-dilute carbon dioxide sources, many traditional separation processes have no cost advantages, but adsorption technologies such as temperature vacuum swing adsorption is one of suitable methods. Thermodynamic exploration has been investigated regarding minimum separation work and second-law efficiency at various concentrations in the air. The influence of concentration, adsorption temperature, desorption temperature and desorption pressure on the energy efficiency has also been evaluated. Results show that the minimum separation work for the level of 400 ppm is approximately 20 kJ/mol. The optimal second-law efficiencies are 44.57%, 37.55% and 31.60%, respectively for 3000 ppm, 2000 ppm and 1000 ppm. It means that a high energy-efficiency capture device in buildings merits attention in the exploration of the possibility of approaching negative carbon buildings.

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2019
Keywords
Thermodynamics, Second-law efficiency, NETs, Direct air capture, TVSA, Buildings
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-246239 (URN)10.1016/j.enconman.2019.01.009 (DOI)000459837600034 ()2-s2.0-85060286434 (Scopus ID)
Note

QC 20190403

Available from: 2019-04-03 Created: 2019-04-03 Last updated: 2019-04-04Bibliographically approved
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