1,721,000 research outputs found
Methanol and Fuel Cell for Cold Ironing Achieving Emission Reduction and Its Economic Assessment
No full textThe completely shipping sector is engaged toward the reduction of greenhouse gas emission. Both IMO and the EU already set their pathways along the GHG strategy aiming to reach a shipping sector fully carbon neutral. The two regulatory bodies issued a first set of requirements with further ones under preparation. High-Speed units will be indeed also involved by these efforts in a very specific way, considering their very peculiar operation profiles. In order to improve the carbon footprint for a high-speed craft, a reference unit (e.g. 50mt in length) is considered, engaging innovative technologies and new fuels. Being the port infrastructures also part of the sustainable mobility, the interaction between the ship and the harbor facilities are also considered. Ships at berth generate their electricity depending on their own auxiliary engines, emitting air pollutants and creating noise. This makes ports a major and growing source of pollution. Therefore, using fuel cell, main aims of this paper are the shore-side power concept economic analysis and the shore-side power and environmental effect
Ammonia as an Alternative Fuel on a Mega-Yacht: An Analysis of Case Studies Using Different Fuel Cell Technologies
No full textTo meet the aim of emission reduction and decarbonization, the study of alternatives to traditional fuels and thermal machines is increasing, in favour of new technologies, such as Fuel Cells (FCs) and batteries, and the use of innovative fuels, such as methanol, hydrogen and ammonia. In this study, the possibility of using ammonia as a hydrogen carrier for FCs has been investigated. In particular, both direct ammonia-fueled FCs (SOFC, AFC) and indirectly fueled FCs (PEMFC) have been considered. The case study of a 64 m length mega-yacht has been considered and the effects of the installation on board of these new technologies on the general arrangements have been evaluated. Different power configurations are proposed to allow both a hybrid and fully electric propulsion to reach zero-emission conditions. A fuel control strategy is also proposed to support the wide load variation
State of the art of high temperature fuel cells in maritime applications
No full textThe paper aims to make the state of the art on the applications of Fuel Cells (FCs) in maritime applications. It synthetically describes the Solid Oxide Fuel Cells and Molten Carbonate Fuel Cells technologies highlighting critical issues and advantages dealing with the maritime sectors. Several projects have been described in literature, the main focus are the assessments of potential for FC use, rules development, feasibility studies and concept design for testing FCs in various vessels. Low temperature FCs, in particular PEMFC fuelled by H2, are suitable for small and medium applications, high temperature FCs (HTFCs) for larger ones. The main conclusions are that no fundamental obstacles for the integration of FC-systems into commercial ships exist as well as no fundamental obstacles with respect to safety
Techno-Economic Comparison of Dual-fuel Marine Engine Waste Energy Recovery Systems
No full textNowadays alternative and innovative energy recovery solutions are adopted on board ships to reduce fuel consumption and harmful emissions. According to this, the present work compares the engine exhaust gas waste heat recovery and hybrid turbocharger technologies, which are used to improve the efficiency of a dual-fuel four-stroke (DF) marine engine. Both solutions aim to satisfy partly or entirely the ship’s electrical and/or thermal loads. For the engine exhaust gas waste heat recovery, two steam plant schemes are considered: the single steam pressure and the variable layout (single or dual steam pressure plant). In both cases, a heat recovery steam generator is used for the electric power energy generation through a steam turbine. The hybrid turbocharger is used to provide a part of the ship’s electric loads as well. The thermodynamic mathematical models of DF engines, integrated with the energy recovery systems, are developed in a Matlab-Simulink environment, allowing the comparison in terms of performance at different engine loads and fuels, which are Natural Gas (NG) and High Fuel Oil (HFO). The use of NG always involves better efficiency of the system for all the engine working conditions. It results that the highest efficiency value achievable is 56% at 50% maximum continuous rating (MCR) engine load
3D data integration for the digital reconstruction of cultural heritage monuments
No full textThe ancient city centers often contain traces of monuments almost completely disappeared, whose few remains are hidden by modern buildings. This is the case for many monumental buildings of the Roman period in Italian cities, that have almost disappeared over time being gradually dismantled for the reusing their construction materials, leaving space to a dense urbanization. Knowledge of such monuments is often approximate and based on historical memories of various kinds. In such situations, three-dimensional surveys and digital 3D modelling reconstructions can be of great support for scientific-archaeological research and for providing a scientifically supported image of cultural heritage sites.This paper shows the work on the emblematic example of the late Roman Circus of Milan, an impressive monument of about 450x85 meters, built when Mediolanum used to be capital of the Western Roman Empire (286-402 A. D). This fact is nowadays almost unknown to most citizens of Milan. The diachronic reconstruction approach is used in order to show the monument in his current state and in his presumed past aspect. The reconstruction is based on a proper mix of quantitative data originated by 3D surveys at present time, and historical sources like ancient maps, drawings, archaeological reports, archaeological restrictions decrees and old photographs. In this panorama, the georeferenced acquired data of the remains play a key role in order to validate the previous reconstruction of the building and to define some fixed points to hypothesize a reliable reconstruction of the area in different historical periods. The experimental activity is defined by the project Cultural Heritage Through Time - CHT2 (http://cht2-project. eu), funded in the framework of the Joint Programming Initiative on Cultural Heritage (JPI-CH) of the European Commission
4D reconstruction by multi-source data fusion: The case of the hidden Roman Circus in Milan
No full textFerry ships: A cost/environmental comparison of innovative solutions for the electric power generation in port
No full textIn order to cope with continuously increasing environmental demands, the maritime sector is
investigating alternative solutions for the power generation on board. These solutions include both alternative
fuel, such as Liquefied Natural Gas (LNG) and hydrogen, and green technologies, such as fuel cells (FC) and
batteries. Although in-port emissions are responsible of a small percentage of the overall emissions, ports constitute sources of concentrated ship harmful emissions, potentially very dangerous for the human health. Moreover,the environmental regulations suggest switching present marine fuels as soon as possible. In this frame, this work investigates innovative solutions for the electric power generation in port for passenger ships in terms of cost and environmental benefits. These can be shore power solutions (such as cold ironing) and on-board solutions (such as dual fuel, fuel cell and others). The results show that some solutions could be more competitive than others according to specific operating conditions. The aim of the study is to identify the most eco-friendly and promising solutions. The cost analysis methodology takes into account the efficiency, fuel costs, operating and maintenance costs and the initial investment costs. The environmental comparison considers the emissions of nitrogen and sulphur oxides, carbon monoxide and dioxide, particulate matter and hydrocarbon
13X Ex-Cu zeolite performance characterization towards H2S removal for biogas use in molten carbonate fuel cells
No full textA 13X zeolite modified with Cu ions (13X Ex-Cu) by means of an innovative technique was employed as adsorbent for H2S removal from biogas, to obtain a desulfurized fuel suitable for molten carbonate fuel cell systems. Sorbent performance was characterized over a wide range of operating conditions typical of biogas mixtures (high H2S content - 200 and 1000 ppmv; CH4 (60%)/CO2 (40%) matrices) and compared to several conventional sorbents. A sensitivity performance analysis was conducted, varying parameters as space velocity, reactor temperature, gas matrix composition and particles size, finalized to identify the optimal conditions for the studied application.
13X Ex-Cu zeolite showed high potentiality for H2S uptake, specifically lowering space velocity, increasing reactor temperature and in presence of high methane concentration in the gas mixture, with adsorption capacity of 40 mg/g under specific and optimized conditions. By means of B.E.T. and XRD analyses, it was demonstrated that the obtained enhanced performance is due to the presence of a large amount of Cu2+ ions, guaranteed by the innovative synthesis procedure, able to realize an efficient physical-chemical adsorption mechanism
Performance Assessment of the Heat Recovery System of a 12 MW SOFC-Based Generator on Board a Cruise Ship through a 0D Model
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