| 1. |
- Li, Shuangjun, et al.
(författare)
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Cyclic performance evaluation of CO2 adsorption using polyethylene terephthalate plastic-waste-derived activated carbon
- 2023
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Ingår i: Fuel. - : ELSEVIER SCI LTD. - 0016-2361 .- 1873-7153. ; 331
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Tidskriftsartikel (refereegranskat)abstract
- Polyethylene terephthalate (PET) plastic-waste-derived activated carbons have recently been developed and exhibit excellent CO(2 )adsorption uptake. However, the CO2-adsorption performance of such recycled materials has only been considered on a basic characterization level and has not yet been evaluated in carbon capture cycles, thereby making biased analyses inevitable. Consequently, a whole chain including the material, process, and cycle is essential for comprehensively analyzing and evaluating novel CO2 adsorbents. Therefore, in this study, various CO2-capture cycles using PET plastic-waste-derived activated carbon adsorbents were numerically simulated, the cyclic CO2-adsorption performances were evaluated, and the application scenario was optimized. A methodology for evaluating the cyclic CO2-adsorption performance of PET plastic-waste-derived activated carbon was proposed for CO(2 )capture. The results suggested that the temperature/vacuum swing adsorption cycle was superior and that its maximum exergy efficiency reached 32.90%.
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| 2. |
- Li, Shuangjun, et al.
(författare)
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Entropy analysis on energy-consumption process and improvement method of temperature/vacuum swing adsorption (TVSA) cycle
- 2019
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Ingår i: Energy. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0360-5442 .- 1873-6785. ; 179, s. 876-889
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 3. |
- Yue, Zhang, et al.
(författare)
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Effect of Nanobubble Evolution on Hydrate Process : A Review
- 2019
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Ingår i: JOURNAL OF THERMAL SCIENCE. - : SPRINGER. - 1003-2169 .- 1993-033X. ; 28:5, s. 948-961
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Forskningsöversikt (refereegranskat)abstract
- 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.
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| 4. |
- Zhao, Ruikai, et al.
(författare)
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A comprehensive performance evaluation of temperature swing adsorption for post-combustion carbon dioxide capture
- 2019
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Ingår i: Renewable & sustainable energy reviews. - : Elsevier. - 1364-0321 .- 1879-0690. ; 114
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Tidskriftsartikel (refereegranskat)abstract
- Carbon dioxide capture from the post-combustion flue gas via temperature swing adsorption is supposed to be a valid technology to mitigate carbon emissions. With regard to the adsorbent development and process improvement, the technologies of temperature swing adsorption for post-combustion carbon dioxide capture have been reviewed and compared in terms of fixed bed, fluidized bed and moving bed. A comprehensive evaluation framework of fixed-bed temperature swing adsorption for CO2 capture has been established. In a four-step fixed-bed cycle, a shortcut model has been utilized. Four typical adsorbent materials, such as activated carbon, zeolite 13X, zeolite NaUSY and Mg-MOF-74, have been chosen in this assessment. The comparative study has been conducted under the same operating conditions, from four aspects using eight performance indicators. Results indicate that Mg-MOF-74 and zeolite 13X reveal excellent performance among the four selected adsorbents. Thereinto, Mg-MOF-74 performs well at four indicators including purity, productivity, specific thermal energy consumption and second-law efficiency; zeolite 13X excels in the other four indicators such as selectivity, recovery, minimum separation work and capture cost. Future work will complete a thorough assessment criterion in evaluating the TSA process for CO2 capture.
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| 5. |
- Zhao, Ruikai, et al.
(författare)
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Comparative study on energy efficiency of moving-bed adsorption for carbon dioxide capture by two evaluation methods
- 2021
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Ingår i: Sustainable Energy Technologies and Assessments. - : ELSEVIER. - 2213-1388 .- 2213-1396. ; 44
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Tidskriftsartikel (refereegranskat)abstract
- Because of the fast heat transfer and the low pressure drop, the technology of moving-bed adsorption for carbon dioxide capture is gathering the momentum in the last decade. The primary aim of this paper is to investigate the influence of various parameters on the energy-efficiency performance of moving-bed adsorption for CO2 capture. The relevant parameters involve desorption temperature, desorption pressure, CO2 capture rate and CO(2 )mole fraction of flue gas. The energy efficiency assessment of moving bed is performed and compared in the light of the minimum separation work and the second-law efficiency. Moreover, two evaluation approaches, which are the thermodynamic carbon pump model and regeneration separation model, are employed and compared as well. Results indicate that the values of minimum separation work for CO(2 )capture by moving bed, which are calculated by regeneration separation model, are about 15% higher than those of thermodynamic carbon pump model under the same conditions. Furthermore, the second-law efficiencies of both models are approximately 10% under the given conditions. It is also found that the regeneration separation model is closer to real status owing to the additional consideration of the adsorption isotherm equilibrium data.
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| 6. |
- Zhao, Ruikai, et al.
(författare)
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Energy-saving pathway exploration of CCS integrated with solar energy : Literature research and comparative analysis
- 2015
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Ingår i: Energy Conversion and Management. - : Elsevier BV. - 0196-8904 .- 1879-2227. ; 102, s. 66-80
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Tidskriftsartikel (refereegranskat)abstract
- One of main technical barriers to a large-scale application of carbon capture and storage (CCS) technology is a significant amount of required energy, e.g., regeneration heat of solvent in the chemical absorption system. Thus, energy consumption and corresponding high operation cost become two primary challenges for the promotion of CCS technology. Meanwhile, energy from the solar source in various forms has already been successfully used as an effective alternative supply in the industrial section for drying, heating and even cooling. Thus, integrating solar energy utilization into the CCS process could be a reasonable option for a sustainable development. A comparative analysis of CCS integrated with solar energy was presented in this paper based on the existing researches. The current status on typical configuration structure, feature and energy-efficiency performance of integrating options is reviewed for post-combustion, pre-combustion and oxygen-combustion systems. Based on these typical CO2 capture systems, a theoretical analysis is conducted for an energy-efficient comparison. Then four typical structures of the post-combustion system, which are highlighted in the review, are chosen as comparative objects for energy-saving and techno-economic evaluation. The results show that systems with a solar-assisted thermal energy and power generation have comparative advantages in term of carbon emission intensity, but the economic cost is increased under the current conditions of the equipment price. Compared to that of baseline case, carbon emission intensity of the case integrated with solar Organic Rankine Cycle can be reduced with a maximum decline of 9.73%, meanwhile the levelized costs of electricity increases 0.01 USD/kW h correspondingly.
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| 7. |
- Zhao, Ruikai, et al.
(författare)
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Solar-assisted pressure-temperature swing adsorption for CO2 capture : Effect of adsorbent materials
- 2018
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Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier. - 0927-0248 .- 1879-3398. ; 185, s. 494-504
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Tidskriftsartikel (refereegranskat)abstract
- Because of the ability to utilize the low-grade solar thermal energy for regeneration, a CO2 capture system characterized by solar-assisted pressure temperature swing adsorption (SOL-PTSA) is studied on the effects of adsorbent materials. A detailed cycle description is firstly presented within the diagram of adsorption isotherm for the energy-efficiency analysis. Typical adsorbent materials, including zeolites and chemical adsorbent, are assessed in terms of sensible heat and latent heat, etc. Then, the energy consumption and the second-law efficiency, which can be considered as lumped indicators from such material parameters, are chosen as performance indicators as well. The influence of separation temperature, desorption temperature, CO2 concentration and CO2 adsorption pressure on system performance are finally obtained. For the chosen three adsorbent materials, the energy consumption of SOL-PTSA system is at the range of 25.96-87.76 kJ/mol, and the corresponding second law efficiencies are at the range of 9.18-26.89%. The effect of adsorbent materials on the energy-efficiency of SOL-PTSA system mainly depends on specific heat, CO2 working capacity and cycle design. In addition, the integration options of solar energy into PTSA technology are also discussed from the standpoint of the utilization of solar grade heat due to two energy loads required for PTSA's operation.
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| 8. |
- Zhao, Ruikai, et al.
(författare)
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Techno-economic analysis of carbon capture from a coal-fired power plant integrating solar-assisted pressure-temperature swing adsorption (PTSA)
- 2019
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Ingår i: Journal of Cleaner Production. - : ELSEVIER SCI LTD. - 0959-6526 .- 1879-1786. ; 214, s. 440-451
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a techno-economic study to seek the feasibility about the proposed system that integrating solar-assisted pressure-temperature swing adsorption (PTSA) into an 800MWe coal-fired power plant. Solar energy has the potential to supply thermal energy demand for carbon capture, which can avoid the energy consumption of the traditional method such as the steam extraction. The performance of the proposed system is largely affected by the climatic conditions and solar collector's types. The assessment criteria include carbon emission intensity (CEO, levelized cost of electricity (LCOE) and cost of CO2 avoidance (COA). By the parametric analysis, the results show that CEI of the novel system with solar thermal collectors is approximately 2g/kWh lower than that of the referenced power plant with CO2 adsorption capture. In addition, CEI of the novel system can be further decrease with the decline of desorption temperature, adsorption pressure and desorption pressure. For the sake of lower LCOE and COA, the prices of the power plant capacity, adsorbents and solar collectors should be reduced. Specifically, LCOE of the system with evacuated tube collector will be lower than that of the reference system with CO2 capture as the price of solar field is lower than 46.08 USD/m2.
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| 9. |
- Zhao, Ruikai, et al.
(författare)
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Thermodynamic analysis on carbon dioxide capture by Electric Swing Adsorption (ESA) technology
- 2018
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Ingår i: Journal of CO2 Utilization. - : Elsevier. - 2212-9820 .- 2212-9839. ; 26, s. 388-396
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Tidskriftsartikel (refereegranskat)abstract
- This study explores the impacts of materials, such as adsorbents and electrodes, on the energy efficiency of a 4-step ESA cycle for CO2 capture. Three types of adsorbents including activated carbon honeycomb monolith (ACHM) and two hybrid adsorbents are compared, and two kinds of electrodes such as aluminum and brass are combined for comparative analysis. Process description of ESA cycle, including feed, electrification, electrification with purge and cooling, is presented via the adsorption isotherm diagram. By the theory of thermodynamic carbon pump, sensitivity analysis of cycle parameters is evaluated in terms of the second-law efficiency (Eff(2nd)) and the electrical heating efficiency (Eff(ele)). The results show that Eff(2nd) of the employed adsorbents is in the range of 1.17%-6.15%, and Effele of the selected electrodes is between 27.46% and 60.91%. Among the three adsorbents, Eff(2nd) of ACHM is the lowest one compared to the others. Similarly, Effele of the combination with brass is superior to that of the groups with aluminum. However, the actual efficiency of ESA cycle is the production of both Eff(2nd) and Eff(ele), which is approximately 1.03%-3.66%. Typical measures are proposed to reduce the heat loss of the adsorbents and electrodes as well for future work.
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| 10. |
- Zhao, Ruikai, et al.
(författare)
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Thermodynamic exploration of temperature vacuum swing adsorption for direct air capture of carbon dioxide in buildings
- 2019
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Ingår i: Energy Conversion and Management. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0196-8904 .- 1879-2227. ; 183, s. 418-426
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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