11 research outputs found
EAFGAS off-gas gas analysis system:
No full textTo be completed after deposition of patent applicatio
Green Shipping: Abatement of Marine Engine Emissions Using an Integrated Catalyst/Srubber Technology
No full textIn the present contribution we report results concerning the abatement of emissions of marine engines which is of a major concerns in terms of contribution to the total emissions due to transportation.
A combined catalytic/scrubber technology capable of effectively reducing NOx, SOx, HC, CO and PM emissions from a marine engine is described. The system has been first investigated in a laboratory micro- plant and to obtain necessary data to dimension a real prototype (1.5MW engine power). The real plant has been used for over one month period studying the effects of S-content and engine load conditions. Very high SOx, PM, HC, CO and substantial NOx conversions have been obtained, showing the feasibility of this integrated technology for marine engines. The advantages and the drawbacks will be discussed
Air Pollution from Mobile Sources: Formation and effects and Abatement Strategies
No full textAn overview of the issue of air pollution from mobile sources is presented in the present chapter. The chapter is divided into three sections. The first section contains a general introduction on specific aspects of air pollution from internal combustion engines. The topics covered include a description of the primary and secondary pollutants formed and their adverse effects on health and the environment; the mechanisms of pollutant formation and, consequently, the factors which affect their formation; and a historical perspective of the legislative measures progressively introduced over the years. Finally, a brief description of the abatement strategies which may be generally adopted will be given (primary methods v secondary methods). The second section describes the state-of-the-art pollution abatement technologies for gasoline, lean-burn and diesel engines. The third section describes aspects related to pollution abatement in the marine sector. Air pollution abatement from ships is of high current interest due the recent and on-going introduction of legislation in the area. The specific problems associated with the marine sector are described, along with the strategies/technologies adopted to affront these problems. However, thanks in part to the success achieved, there has been a shift in emphasis of the focus of the problem, which has evolved from gasoline-fuelled engines, to diesel and lean-burn gasoline engines to, more recently, off-road vehicles and marine engines. The present contribution will centre on the development of emission abatement from road vehicles, which have been largely responsible for the technological advances made in the field; and marine engines, which have recently become the subject of attention and can be considered to represent the challenge for the future. The situation regarding off-road vehicles will not be specifically considered as related solutions are derived from the above quoted areas. The contribution is based on a seminar held at the summer school of the International Ph. D in Environmental Science and Engineering, Cagliary, September 2008
Green shipping: Marine engine pollution abatement using a combined catalyst/seawater scrubber system. 1. Effect of catalyst
No full textA marine engine pollution abatement system was constructed and tested on a 1.5 MW auxiliary marine engine. The integrated system, designed to abate all of the currently legislated emissions from marine engines, consisted of a monolithic Pt/Al2O3 oxidation catalyst and a seawater scrubber, both of suitable dimensions for the engine size. The test results obtained showed the general validity of the approach adopted, as significant abatement of emissions was achieved. However, under the conditions used, the system showed some limitations with regard to the sulphur content of the fuel. On the basis of the results obtained, the system can be used with fuel sulphur content of up to 0.4%, while problems were encountered when a fuel with a sulphur content of 2.0% was used. Whereas the catalytic section operated satisfactorily, fine tuning of the scrubber operating conditions is necessary to improve abatement of NOx and increase the range of fuel sulphur which can be used with the system
Green shipping: Marine engine pollution abatement using a combined catalyst/seawater scrubber system. 1. Effect of catalyst
No full textA marine engine pollution abatement system was constructed and tested on a 1.5 MW auxiliary marine engine. The integrated system, designed to abate all of the currently legislated emissions from marine engines, consisted of a
monolithic Pt/Al2O3 oxidation catalyst and a seawater scrubber, both of suitable dimensions for the engine size. The test results obtained showed the general validity of the approach adopted, as significant abatement of emissions was achieved. However, under the conditions used, the system showed some limitations with regard to the sulphur content of the fuel. On the basis of the results obtained, the system can be used with fuel sulphur content of up to 0.4%,while problems were encountered when a fuel with a sulphur content of 2.0% was used. Whereas the catalytic section operated satisfactorily, fine tuning of the scrubber operating conditions is necessary to improve abatement of NOx and increase the range of fuel sulphur which can be used with the system
Effect of the support on activity of silver catalysts for the selective reduction of NO by propene
No full textUse of zirconia, ceria–zirconia and ceria supports for Ag-based lean deNOx catalysts lowers the temperature range of activity by about 150–200K with respect to Al2O3-supported analogues. Ex situ characterisation of the catalysts indicates that this remarkable effect is associated with a role of the support rather than Ag dispersion. The crucial role of the support is further evidenced by suppression of CO formation over these catalysts and by significant support-related differences when SO2 is added tothe feed. The presence of ceria in the formulation results in an initial resistance to the deactivating effectof SO2; while the use of both zirconia and ceria–zirconia facilitates reactivation after sulphur poisoning
Green cork-based innovative resilient and insulating materials: Acoustic, thermal and mechanical characterization
No full textNowadays, efficient thermal insulation is a principal requirement for buildings and, accordingly, huge amounts of insulators are applied in the constructions, particularly for external walls, radiant floor, etc. Acoustic insulation is another of the most stringent parameters to be taken into account both in the construction of new buildings or their rejuvenation in order to obtain good internal comfort. On the other hand, the use of bio-derived construction materials is gaining stronger and stronger interest. Cork has a low density (120-240 kg m-3) and can be regarded as a hydrophobic and viscoelastic material, with good thermal and acoustic insulation properties. With respect to wood, it presents good resistance to microbial activity and water. Last but not least is the negative carbon fingerprint of cork-based materials. Recently a new class of polymer - inorganic oxides - cork composites has been reported, which features enhanced thermal and acoustic properties with respect to traditional commercial composites and that maintains, at the same time, all the favorable properties of conventional cork-base composites
Epitaxial Growth of Hexagonal Boron Nitride on Ir(111)
No full textThe formation of a hexagonal boron nitride (h-BN) layer through dissociation of borazine (B3N3H6) molecules on Ir(111) has been investigated by a combination of X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure, temperature-programmed desorption, and lowenergy electron diffraction
Integration of catalytic technology into marine engine pollution abatement system
No full text2009/2010La ricerca condotta nel presente lavoro di tesi è stata condotta nell’ambito del progetto ECOMOS. Il progetto consiste in ricerca di base e ricerca applicata e lo scopo del lavoro era sviluppate tecnologie innovative per l’abbattimento degli inquinanti gassosi prodotti da motori marini. In tal senso il lavoro è stato condotto su due filoni principali:
- Uno riguardante la ricerca di base, in cui sono stati verificati gli effetti del supporto su catalizzatori a base di argento operanti in condizioni di miscela magra utilizzando un idroreattore catalitico.
- Uno riguardante la ricerca applicata, che ha richiesto l’analisi e razionalizzazione dello stato dell’arte circa l’abbattimento delle emissioni gassose inquinanti nel settore marino allo scopo di proporre un modello di sistema integrato per l’abbattimento; la verifica della fattibilità della proposta utilizzando catalizzatori modello a base di platino; lo studio del disegno e la costruzione di un impianto micro pilota su scala di laboratorio per l’abbattimento delle emissioni di un motore marino facente uso di catalizzatori a base di Pt/Al2O3 ed infine la realizzazione di un impianto pilota con la collaborazione di Cetena.
I principali risultati ottenuti possono essere riassunti in:
- Ricerca di base:
o Il supporto risulta avere un forte effetto sull’attività catalitica
o L’attività catalitica può essere modificata scegliendo l’opportuno supporto
o La resistenza all’avvelenamento provocato dalla presenza di zolfo nei gas può essere aumentata tramite l’introduzione di zirconia nel supporti, ma ulteriori test sono necessari per razionalizzare completamente quanto osservato
- Ricerca applicata:
o Il catalizzatore a base di platino supportato su allumina, Pt/Al2O3, ha dimostrato di essere stabile ed attivo anche in presenza di elevate concentrazioni di SO2 nella fase gassosa suggerendo la possibilità di utilizzo nel settore marino.
o È stato identificato un inaspettato fenomeno di condensazione, per la cui completa caratterizzazione sono richiesti ulteriori test.
o Acqua ed anidride carbonica hanno effetti limitati sull’ossidazione dell’ossido di azoto mentre sopprimono la reazione di condensazione.
o La presenza di idrocarburi sopprime l’ossidazione di NO
o I test sull’impianto pilota di laboratorio hanno dimostrato che il catalizzatore scelto è attivo nell’ossidazione di NO, ma si conferma la necessità di ossidare prima tutti gli HC.
o È stata confermata la necessità di ossidare No ad NO2 qualora si vogliano abbattere le emissioni di ossidi di azoto tramite assorbimento in acqua di mare mentre si è confermata l’efficacia per l’abbattimento di SO2.
o L’impianto di laboratorio ha consentito il dimensionamento del catalizzatore per l’impianto pilota.
o I problemi riscontrati nell’impianto di laboratorio hanno suggerito modifiche che sono state applicate all’impianto pilota.The research conducted in the present thesis was carried out within the framework of the ECOMOS project. The project consists of basic and applied research and overall scope of the work was to develop novel marine pollution abatement technologies. Accordingly, the work was carried out along two main directions:
- fundamental research, in which the effect of the support on lean deNOx activity of Ag-based catalyst were investigated using a catalytic microreactor;
- and applied research, which involved a recognition and rationalization of the state of the art in marine pollution abatement to purpose a model of integrated system; the verification of the feasibility of the purpose, using a model Pt catalyst; the study of the design, of the layout and the construction and testing of a laboratory-scale plant for the abatement of emissions from marine engines using Pt / Al2O3 catalysts and the dimensioning of a pilot plant in collaboration with Cetena.
The main results found on the two directions are summarized in the following lists:
- Basic studies: HC SCR on Ag based catalyst:
The support effect is clearly evidenced as a main contributor to catalytic activity;
The activity can be tuned by using appropriate supports;
The resistance to sulphur poisoning can be improved by the introduction of zirconia in the support, but further test are needed to fully address this observation;
- Fundamental studies:
The Pt/Al2O3 catalyst tested in the microreactor demonstrated activity and stablity even in the presence of high SO2 concentration suggesting the possibility of its use in the marine sector;
An unexpected phenomenon was found, the condensation process in which NOx are dissolved in SO3 mists, which need further studies to be completely elucidated;
H2O and CO2 have only small negative influence on the NO oxidation but suppress the condensation;
HC suppress NO oxidation, the necessity of oxidising the HC before NO oxidation becomes effective, has been demonstrated;
Pilot plant tests revealed that the Ecocat catalyst is active for NO oxidation but the need to oxidise all the carbonaceous species was again confirmed;
The monolith has an activity comparable to that found in the microreactor studies using model mixtures. In this way activities of powdered catalysts could be related to honeycomb analogues;
The need to oxidize NO to NO2 to favour the absorption into the scrubber was confirmed;
The scrubber effectively abates SOx;
The problems of crusting and the excessive pressure drop found in the micro scrubber provided indications on how to modify the pilot plant;
The real plant design and construction has been completed, in cooperation with the industrial partners;
The catalytic section was designed and completed;
The pilot plant is now ready for the tests.XXIII Ciclo198
