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showing 10 items of 3263 documents
STUDIO DI UN AMMORTIZZATORE ELETTROMAGNETICO A RECUPERO DI ENERGIA
2013
Questo lavoro ha come obiettivo principale lo studio teorico e con supporto di software F.E.M. di un dispositivo che consenta recupero energetico da una sospensione automobilistica. In sostituzione allo smorzatore viscoso, che dissipa l’energia cinetica del veicolo a seguito dell’attraversamento di strade sconnesse o ostacoli più marcati, si è usato uno smorzatore elettromagnetico che svolga le funzioni dello smorzatore viscoso consentendo un recupero di energia elettrica. Lo smorzatore elettromagnetico è di tipo a magneti permanenti e il suo funzionamento si basa sul fenomeno dell’induzione elettromagnetica. Il modello matematico descrive il funzionamento dello smorzatore, restituendo i va…
Photocatalytic process intensification by coupling with pervaporation
2011
The integration of photocatalysis with a membrane separation process, in particular pervaporation, permits the recovery of valuable intermediate compounds (aromatic aldehydes) while they are produced avoiding their further degradation in the reactive ambient. In this way the yield and the conversion are enhanced. The coupling of the two processes is straightforward and the integration is complete even maintaining pervaporation and photocatalysis in two separate apparatuses provided that the process stream is continuously recycled at a sufficiently high flow rate. Additional advantages are: higher degree of purification of the aldehyde in the powder-free product stream, semicontinuous produc…
PMRs Utilizing Non–Pressure-Driven Membrane Techniques
2018
In the present chapter it is shown how photocatalytic membrane reactors utilizing membrane processes, which are not pressure driven, can exploit various mechanisms to obtain a substantial improvement of the process. The fundamentals of this particular type of membrane reactors are reviewed including the effects of the most important parameters and the methods and rules of coupling photocatalysis and membrane separation. The survey of the studies on photocatalytic membrane reactors (PMRs) utilizing pervaporation, dialysis, membrane contactors and membrane distillation offers the opportunity of discussing the advantages with respect to PMRs adopting pressure driven membrane processes. Indeed,…
Photocatalytic ozonation:Maximization of the reaction rate and control of undesired by-products
2014
In theso-calledphotocatalyticozonation(PO)synergisticeffectsbetweenphotocatalysisandozonation enhance therateofoxidationoforganiccompounds,thereforethisintegratedprocessisverypromising for useinwatertreatment.Inthepresentwork,itisdemonstratedthattheimprovementthatcanbe obtained bytheintegratedprocessincomparisonwiththeuncoupledprocessesdependsontherelative weight between photocatalysis and ozonation. In this respect, it has been found that a relatively low rate of photocatalysis (0.3 times the rate of ozonation)issufficienttogetthehighestsynergyandtomaximize the performancesintheoxidationofformate,theadoptedmodelorganiccompound.Thebenefitsof the couplingofphotocatalysistoozonationarenotlimi…
Modelling and bench scale investigation of inclined dense jets
2002
Hierarchical modelling of electrodialysis desalination process
2017
In recent years, thanks to the development of ion exchange membranes (IEMs) manufacturing industry, Electrodialysis (ED) is spreading as a viable alternative to the more common membrane desalination processes. Therefore, many research efforts have been recently devoted to studying this process both via experimental and modelling activities. In the present work a novel mathematical model for ED was developed using a multi-scale approach. This method allows to build a hierarchical simulation tool that is able to gauge the impact of all the phenomena involved in the process. The lower-hierarchy model describes the behaviour of the elementary unit of an ED stack, namely cell pair. This model is…
RED Heat-to-Power: conversione di calore di scarto in energia elettrica mediante elettrodialisi inversa a ciclo chiuso
2016
La produzione di energia da gradienti salini si sta affermando come una valida alternativa alle tradizionali fonti di energia rinnovabili. In particolare l’elettrodialisi inversa (RED) è di certo tra le tecnologie più promettenti per effettuare la conversione di gradienti salini in energia utile. Un recente sviluppo è l’utilizzo del processo RED a ciclo chiuso con soluzioni saline artificiali, nel quale le soluzioni in uscita dall’unità RED vengono rigenerate all’interno di un’unità di rigenerazione termica, che ripristina il gradiente salino iniziale. L’utilizzo del sistema a ciclo chiuso premette dunque di convertire calore a bassa temperatura (e.g. calore di scarto a T <70-100°C) in e…
Ion Exchange Membrane deformation and its relevance in Reverse ElectroDialysis
2017
Reverse electrodialysis (RED) is an innovative electro-membrane technology for electric energy generation from two salt solutions with different concentration. This different concentration is the driving force to a selective movement of ions from the concentrate channel to the dilute one oriented by Ion Exchange Membranes (IEMs). Typically, RED stack are made by piling alternatively cation exchange membranes and anion exchange membranes with the aid of spacers or profiles built on the membrane surface. Two electrodic compartments are placed at the two ends of the stack, where the ion flux generated is converted into an electric current able to circulate through an external load connected to…
Coupling CFD simulation with a simplified process model for reverse electrodialysis units
2017
Salinity gradient between two solutions is a renewable source of energy. Among the technologies able to exploit the salinity gradient, reverse electrodialysis (RED) is an electrochemical process for electrical power generation through direct conversion. Ion exchange membranes, piled alternately and separated by net spacers or membrane profiles, are the key elements of a RED stack. A multiplex phenomenology occurs in RED units; Ohmic and non-Ohmic (due to concentration changes) voltage losses and pressure drop are the main issues, and the membrane/channel configuration is crucial for the stack performance. In this framework, mathematical modelling can be a powerful tool for predictive purpos…