scholarly journals Localized Electroconvection at Ion-Exchange Membranes with Heterogeneous Surface Charge

2021 ◽  
Author(s):  
Felix Stockmeier ◽  
Daniel Felder ◽  
Steffen Eser ◽  
Malte Habermann ◽  
Petar Peric ◽  
...  
Keyword(s):  
Energy Demand ◽  
Scale Up ◽  
Limiting Current ◽  
Surface Charges ◽  
Economic Operation ◽  
Limiting Current Density ◽  
Space Time Yield ◽  
Desalination Plants ◽  
Rotational Direction ◽  
Letter Pattern

Abstract Operating electrochemical membrane processes beyond the limiting current density bears the potential to decrease the investment cost of desalination plants significantly. However, while there are strategies for successfully reducing energy demand by shortening the plateau region, their influence on the formation of electroconvection is still unknown. This study demonstrates control over the electroconvective vortices' rotational direction and position using a surface patterning method. We compare the development of electroconvection at two membranes modified with patterns of different surface charges. We analyze the electroconvective vortex field's build-up, the vortices' rotational direction, and structural stability in the steady-state. Finally, we showcase the control possibilities by enforcing a specific structure along an asymmetric letter pattern. Such tailor-made patterns have the potential to diminish the plateau region's energy loss completely. Furthermore, the scale-up of these membranes to industrial processes will allow the economic operation in the overlimiting regime, significantly increasing their space-time yield.

scholarly journals Limiting Current Density of Oxygen Reduction under Ultrathin Electrolyte Layers: From the Micrometer Range to Monolayers

2021 ◽  
Vol 8 (4) ◽  
pp. 712-718
Author(s):  
Xiankang Zhong ◽  
Matthias Schulz (née Uebel) ◽  
Chun‐Hung Wu ◽  
Martin Rabe ◽  
Andreas Erbe ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Current Density ◽  
Limiting Current ◽  
Limiting Current Density

scholarly journals A Theoretical Study on Reversible Solid Oxide Cells as Key Enablers of Cyclic Conversion between Electrical Energy and Fuel

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4517
Author(s):  
Saheli Biswas ◽  
Shambhu Singh Rathore ◽  
Aniruddha Pramod Kulkarni ◽  
Sarbjit Giddey ◽  
Sankar Bhattacharya
Keyword(s):  
Energy Demand ◽  
Electrode Materials ◽  
Scale Up ◽  
High Capacity ◽  
Electrical Energy ◽  
Solid Oxide ◽  
Lower Efficiency ◽  
Internal Reforming ◽  
Fuels And Chemicals ◽  
The Cost

Reversible solid oxide cells (rSOC) enable the efficient cyclic conversion between electrical and chemical energy in the form of fuels and chemicals, thereby providing a pathway for long-term and high-capacity energy storage. Amongst the different fuels under investigation, hydrogen, methane, and ammonia have gained immense attention as carbon-neutral energy vectors. Here we have compared the energy efficiency and the energy demand of rSOC based on these three fuels. In the fuel cell mode of operation (energy generation), two different routes have been considered for both methane and ammonia; Routes 1 and 2 involve internal reforming (in the case of methane) or cracking (in the case of ammonia) and external reforming or cracking, respectively. The use of hydrogen as fuel provides the highest round-trip efficiency (62.1%) followed by methane by Route 1 (43.4%), ammonia by Route 2 (41.1%), methane by Route 2 (40.4%), and ammonia by Route 1 (39.2%). The lower efficiency of internal ammonia cracking as opposed to its external counterpart can be attributed to the insufficient catalytic activity and stability of the state-of-the-art fuel electrode materials, which is a major hindrance to the scale-up of this technology. A preliminary cost estimate showed that the price of hydrogen, methane and ammonia produced in SOEC mode would be ~1.91, 3.63, and 0.48 $/kg, respectively. In SOFC mode, the cost of electricity generation using hydrogen, internally reformed methane, and internally cracked ammonia would be ~52.34, 46.30, and 47.11 $/MWh, respectively.

scholarly journals Demineralization of Rehydrated Cheese Whey by Electrodialysis. Effects of deashing rates and solid concentration on limiting current density.

1991 ◽  
Vol 17 (5) ◽  
pp. 1006-1011 ◽  
Author(s):  
Yasunobu Hiraoka ◽  
Akira Tomizawa ◽  
Tatsuki Oguchi ◽  
Etsuko Suzuki ◽  
Masanobu Koutake
Keyword(s):  
Current Density ◽  
Cheese Whey ◽  
Limiting Current ◽  
Solid Concentration ◽  
Limiting Current Density

Polarization Characteristics to Wear Ratio of Anti-Fouling Paint

2015 ◽  
Vol 1110 ◽  
pp. 179-184
Author(s):  
Kyung Man Moon ◽  
Dong Hyun Park ◽  
Yun Hae Kim ◽  
Tae Sil Baek
Keyword(s):  
Current Density ◽  
Corrosion Potential ◽  
Wear Test ◽  
Life Time ◽  
Point Of View ◽  
Limiting Current ◽  
Limiting Current Density ◽  
Wear Ratio ◽  
Polarization Characteristics ◽  
Lower Variation

Recently, anti-fouling paints which does not include the poison components such as tin (Sn) free, copper (Cu) free have been increasingly developed in order to decrease the contamination of marine environment. Moreover, the wear ratios of these anti-fouling paints are very important problem to prolong their life time in economical and environmental point of view. In this study, four types of anti-fouling paints as self-polishing type were investigated on the relationship between their polarization characteristics and wear ratios. Relationship between wear ratio and variation ratio of polarization resistance measured in corrosion potential was not well matched with each other. However, there was a good agreement between the wear ratio and variation ratio of diffusion limiting current density, for example, the higher or the lower variation ratio of diffusion limiting current density, wear ratio also increased or decreased respectively. Consequently, it is suggested that we can qualitatively expect the life time and wear degree of anti-fouling paint by only measuring the polarization characteristics before the wear test is practically performed in the field.Keywords: Anti-fouling paint, Self-polishing type, Polarization characteristics, Wear ratio, Diffusion limiting current density, Corrosion Potential

Limiting current density in a crossed-field nanogap

2001 ◽  
Vol 64 (1) ◽  
Author(s):  
L. K. Ang ◽  
T. J. T. Kwan ◽  
Y. Y. Lau
Keyword(s):  
Current Density ◽  
Limiting Current ◽  
Limiting Current Density

scholarly journals Achieving Net Zero Carbon Dioxide by Sequestering Biomass Carbon

2020 ◽  
Author(s):  
Jeffrey Amelse
Keyword(s):  
Carbon Dioxide ◽  
Carbon Cycle ◽  
Co2 Emissions ◽  
Energy Demand ◽  
Co2 Sequestration ◽  
Fossil Fuels ◽  
Scale Up ◽  
Biomass Carbon ◽  
Net Zero ◽  
The World

Mitigation of global warming requires an understanding of where energy is produced and consumed, the magnitude of carbon dioxide generation, and proper understanding of the Carbon Cycle. The latter leads to the distinction between and need for both CO2 and biomass CARBON sequestration. Short reviews are provided for prior technologies proposed for reducing CO2 emissions from fossil fuels or substituting renewable energy, focusing on their limitations. None offer a complete solution. Of these, CO2 sequestration is poised to have the largest impact. We know how to do it. It will just cost money, and scale-up is a huge challenge. Few projects have been brought forward to semi-commercial scale. Transportation accounts for only about 30% of U.S. overall energy demand. Biofuels penetration remains small, and thus, they contribute a trivial amount of overall CO2 reduction, even though 40% of U.S. corn and 30% of soybeans are devoted to their production. Bioethanol is traced through its Carbon Cycle and shown to be both energy inefficient, and an inefficient use of biomass carbon. Both biofuels and CO2 sequestration reduce FUTURE CO2 emissions from continued use of fossil fuels. They will not remove CO2 ALREADY in the atmosphere. The only way to do that is to break the Carbon Cycle by growing biomass from atmospheric CO2 and sequestering biomass CARBON. Theoretically, sequestration of only a fraction of the world’s tree leaves, which are renewed every year, can get the world to Net Zero CO2 without disturbing the underlying forests.

scholarly journals Uncoupling Foam Fractionation and Foam Adsorption for Enhanced Biosurfactant Synthesis and Recovery

2020 ◽  
Vol 8 (12) ◽  
pp. 2029
Author(s):  
Christian C. Blesken ◽  
Tessa Strümpfler ◽  
Till Tiso ◽  
Lars M. Blank
Keyword(s):  
Scale Up ◽  
Recovery Process ◽  
Downstream Processing ◽  
Biosurfactant Production ◽  
Foam Fractionation ◽  
Pseudomonas Putida Kt2440 ◽  
Culture Volume ◽  
Product Removal ◽  
Fractionation Column ◽  
Space Time Yield

The production of biosurfactants is often hampered by excessive foaming in the bioreactor, impacting system scale-up and downstream processing. Foam fractionation was proposed to tackle this challenge by combining in situ product removal with a pre-purification step. In previous studies, foam fractionation was coupled to bioreactor operation, hence it was operated at suboptimal parameters. Here, we use an external fractionation column to decouple biosurfactant production from foam fractionation, enabling continuous surfactant separation, which is especially suited for system scale-up. As a subsequent product recovery step, continuous foam adsorption was integrated into the process. The configuration is evaluated for rhamnolipid (RL) or 3-(3-hydroxyalkanoyloxy)alkanoic acid (HAA, i.e., RL precursor) production by recombinant non-pathogenic Pseudomonas putida KT2440. Surfactant concentrations of 7.5 gRL/L and 2.0 gHAA/L were obtained in the fractionated foam. 4.7 g RLs and 2.8 g HAAs could be separated in the 2-stage recovery process within 36 h from a 2 L culture volume. With a culture volume scale-up to 9 L, 16 g RLs were adsorbed, and the space-time yield (STY) increased by 31% to 0.21 gRL/L·h. We demonstrate a well-performing process design for biosurfactant production and recovery as a contribution to a vital bioeconomy.

scholarly journals Research on Economic Operation Strategy of CHP Microgrid Considering Renewable Energy Sources and Integrated Energy Demand Response

2019 ◽  
Vol 11 (18) ◽  
pp. 4825 ◽  
Author(s):  
Jun Dong ◽  
Shilin Nie ◽  
Hui Huang ◽  
Peiwen Yang ◽  
Anyuan Fu ◽  
...  
Keyword(s):  
Renewable Energy ◽  
Demand Response ◽  
Energy Demand ◽  
Renewable Energy Sources ◽  
Rapid Development ◽  
Utilization Efficiency ◽  
Energy Output ◽  
Mixed Integer ◽  
Energy Structure ◽  
Economic Operation

Renewable energy resources (RESs) play an important role in the upgrading and transformation of the global energy structure. However, the question of how to improve the utilization efficiency of RESs and reduce greenhouse gas emissions is still a challenge. Combined heating and power (CHP) is one effective solution and has experienced rapid development. Nevertheless, with the large scale of RESs penetrating into the power system, CHP microgrid economic operation faces great challenges. This paper proposes a CHP microgrid system that contains renewable energy with considering economy, the environment, and system flexibility, and the ultimate goal is to minimize system operation cost and carbon dioxide emissions (CO2) cost. Due to the volatility of renewable energy output, the fuzzy C-means (FCM) and clustering comprehensive quality (CCQ) models were first introduced to generate clustering scenarios of the renewable energy output and evaluate the clustering results. In addition, for the sake of improving the flexibility and reliability of the CHP microgrid, this paper considers the battery and integrated energy demand response (IEDR). Moreover, the strategy choices of microgrid operators under the condition of grid-connected and islanded based on environment and interest aspects are also developed, which have rarely been involved in previous studies. Finally, this stochastic optimization problem is transformed into a mixed integer linear programming (MILP), which simplifies the calculation process, and the results show that the operation mode under different conditions will have a great impact on microgrid economic and environmental benefits.

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