Search results for "Pollution"
showing 10 items of 2765 documents
Performance of a RED system with ammonium hydrogen carbonate solutions
2016
The use of closed-loop salinity gradient power (SGP) technologies has been recently presented as a viable option to generate power using low-grade heat, by coupling a SGP unit with a thermally-driven regeneration process in a closed loop where artificial solutions can be adopted for the conversion of heat into power. Among these, the closed-loop reverse electrodialysis (RED) process presents a number of advantages such as the direct production of electricity, the extreme flexibility in operating conditions and the recently demonstrated large potentials for industrial scale-up. Ammonium hydrogen carbonate (NH4HCO3) is a salt suitable for such closed-loop RED process thanks to its particular …
REAPOWER – USE OF DESALINATION BRINE FOR POWER PRODUCTION THROUGH REVERSE ELECTRODIALYSIS
2015
Salinity gradient power (SGP) represents a viable renewable energy source associated with the mixing of two solutions of different salinities. Reverse electrodialysis (SGP-RE or RED) is a promising technology to exploit this energy source and directly generate electricity. However, although the principle of this technology is well known since several years, further R&D efforts are still necessary in order to explore the real potential of the SGP-RE process. With this regard, the aim of the REAPower project ( [GRAPHICS] ) is the development of an innovative system for power production by SGP-RE process, using sea (or brackish) water as a diluted solution and brine as a concentrate. The use o…
CFD analysis of the fluid flow behavior in a reverse electrodialysis stack
2012
Salinity Gradient Power by Reverse Electrodialysis (SGP-RE) technology allows the production of electricity from the different chemical potentials of two differently concentrated salty solutions flowing in alternate channels suitably separated by selective ion exchange membranes. In SGP-RE, as well as in conventional ElectroDialysis (ED) technology, the process performance dramatically depends on the stack geometry and the internal fluid dynamics conditions: optimizing the system geometry in order to guarantee lower pressure drops (DP) and uniform flow rates distribution within the channels is a topic of primary importance. Although literature studies on Computational Fluid Dynamics (CFD) a…
Reverse electrodialysis with NH4HCO3-water systems for heat-to-power conversion
2017
Abstract A Reverse ElectroDialysis Heat Engine (REDHE) system operating with “thermolytic” ammonium hydrogen-carbonate (NH4HCO3) aqueous solutions as working fluids is studied. The engine is constituted by (i) a RED unit to produce electric power by mixing the solutions at different salinity and (ii) a thermally-driven regeneration unit including a stripping and an absorption column to restore the initial salinity gradient thus closing the cycle. In the present work only the RED unit and the stripping column are taken into account. In particular, a simplified integrated process model for the whole cycle was developed: it consists of (i) a lumped parameter model for the RED unit validated wi…
CFD prediction of scalar transport in thin channels for reverse electrodialysis
2014
Reverse ElectroDialysis (RED) is a very promising technology allowing the electrochemical potential difference of a salinity gradient to be directly converted into electric energy. The fluid dynamics optimization of the thin channels used in RED is still an open problem. The present preliminary work focuses on the Computational Fluid Dynamics (CFD) simulation of the flow and concentration fields in these channels. In particular three different configurations were investigated: a channel unprovided with a spacer (empty channel) and two channels filled with spacers, one made of overlapped filaments the other of woven filaments. The transport of two passive scalars, representative of the ions …
Reactive crystallisation process for magnesium recovery from concentrated brines
2014
Seawater brines, generated either by natural or anthropic processes, often cause significant environmental issues related to their disposal. A clear example is the case of brines from desalination plants, which can have severe environmental impacts on the receiving water body. On the other side, brines can represent a rich and appealing source of raw materials, especially when they are very concentrated, as it happens with bitterns (i.e. exhausted brines) produced in saltworks. In particular, magnesium concentration can reach values up to 30-40 kg/m3 of brine, which is 20-30 times that of typical seawater. An experimental campaign has been carried out in the present work for assessing the p…
CO2 reduction exploiting RES for EV charging
2017
The world is facing an urgent need to reduce emissions, limiting pollution for a better quality of life. This objective has to be reached by all cities and governments worldwide. This paper focuses on the field of transportation, which is greatly responsible for air pollution, mainly in cities and urban areas such as towns, airports and seaports. The diffusion of electric vehicles (EVs) enables a significant reduction of air pollutants emitted by combustion engines; however, their recharge can affect the total pollution by their increasing energy demand. A solution is the use of Renewable Energy Sources (RES) to charge EVs. This paper analyzes the feasibility of integrating EVs and RES, foc…
A mobile application for assessment of air pollution exposure
2013
In this paper the architecture of a mobile air quality monitoring system is introduced. A mobile application will act as a personal assistant, monitoring and giving advices about gas pollutants daily exposure. Currently in development stage as part of a larger air quality monitoring system project, the application will enable users to monitor their daily exposure to gas pollutants by combining user location data and urban air quality information provided by the network of fixed monitoring stations of the city of Palermo.
Cardiovascular effects of occupational exposure to urban airborne pollution on a group of newsagents in the city of Palermo
2014
Aims: To verify the possible correlation between exposure to airborne particulate matter the average size less than 10 μm (PM 10) of a group of newsagents working in kiosks in Palermo and evidence of carotid intimal thickening. Materials and methods: data were collected relating to environmental monitoring of airborne pollutants. We have selected a sample of newsagents, who were submitted to some clinical investigations, including the carotid echo-color doppler examination. Results: The results show no correlation between the location of the kiosks, and the presence of intimal thickening. Conclusion: Exposition to urban pollutants in Palermo is likely homogenous in the different areas and c…
A DYNAMIC PERFORMANCE MANAGEMENT APPROACH TO ASSESS HOW DECENTRALISATION POLICIES MAY REDUCE ENVIRONMENTAL POLLUTION FROM MINES IN ZAMBIA
The economics of pollution in general and pollution control in particular is a relatively new branch of economic science. This has brought about economic and social interest due to the fact that most of the pollution is caused by economic activity such as mining. Pollution from mining has become a world-wide problem. While environmental problems vary in detail, it is a fact that mining emits damaging pollutants, a reason this study was undertaken. As a result of this, threats to the environment and human health continue to escalate. This research aimed at investigating how a Dynamic Performance Management approach, through System Dynamics, may support policy-makers and public managers in im…