1,495 research outputs found
Matteo Ricci filosofo. Appunti per una ricerca
No full textIl saggio intende analizzare la formazione letterario-filosofica di Matteo Ricci ricevuta a Roma presso il Collegio Romano, il contesto filosofico cinese nel quale Ricci operò e i contributi filosofici di Ricci alla cultura cinese
Modeling the carbonator of a Ca-looping process for CO 2 capture from power plant flue gas
No full textThe calcium-looping process is a promising technique for CO2 capture from coal-fired power plants and for reducing GHG emissions from the power generation sector. This paper presents a calculation model of the carbonator, the key reactor of the Ca-looping process, where CO2 is captured as a result of its reaction with CaO. The model presented is based on the Kunii–Levenspiel theory for circulating fluidized bed and on the recent findings on the properties of CaO as a CO2 sorbent, while taking into account the effects of coal ash and sulfur species.
This model can be used for process optimization and for the prediction of the performance of power plants based on the Ca-looping process. Also presented in this paper are the results of a sensitivity analysis of the primary parameters that influence the performance of the carbonator. These results confirm the feasibility of the Ca-looping process with reactors of reasonable size for industrial applications and highlight the importance of the properties of the Ca-based sorbent as they highly affect the carbonator's performance
On the effects of syngas clean-up temperature in IGCCs
No full textThis paper deals with the thermodynamic analysis of an IGCC power plant with hot syngas clean-up, where sulfur, particulate matter and trace contaminants are removed without cooling the syngas down to near-ambient temperature. With particular attention to the simulation of the desulfurization unit, adopting a regenerative process using a ZnO-based sorbent, a range of clean-up temperatures was investigated in order to evaluate its effects on overall plant performance. The study reveals the attractive chance of achieving overall electric efficiencies around 50%. However, a limited sensitivity of IGCC efficiency on desulfurization temperature was also obtained, since no significant improvements were accomplished for temperatures over 400°C. In order to support and better understand the results, a second law analysis was also carried out for the assessed cases. In addition, the effects of syngas clean-up temperature on the design and operation of the main IGCC processes and components, which can be relevant, were discussed.</jats:p
Terre di mezzo: il cinema di Matteo Garrone.
No full textIl saggio indaga la “terra di mezzo”, per citare il titolo del primo lungometraggio di Matteo Garrone del 1996, in cui
trova il proprio orizzonte d’elezione tutto il cinema dell’autore romano, con le creature che lo abitano, i luoghi che lo punteggiano, ma anche per lo stile che lo connota. Terra di mezzo estetica tra vero e falso, realismo e artificio, bellezza e bruttezza; terra di mezzo etica tra virtù e abiezione, moralità e immoralità, decenza e indecenza; terra di mezzo esistenziale tra giovinezza e vecchiaia, età infantile e condizione adulta, vita e morte
Optimisation of ship-based CO2 transport chains from Southern Europe to the North Sea
No full textAmong the technologies for climate change mitigation, carbon capture and storage is considered as a technically and economically viable option to reduce CO2 emissions from hard-to-abate industrial sectors. When it comes to CO2 logistics, ship-based chains are emerging as an attractive alternative to other CO2 transport modes (e.g., pipelines), as these could exhibit lower operational risk, higher infrastructural flexibility, and lower costs. This work provides insights into the cost of optimal ship-based CO2 transport chains at a European level, by proposing a detailed economic model of CO2 transport by ship, including all the echelons of the infrastructure (i.e., liquefaction, buffer storage, loading, ship, conditioning, and unloading). The final aim is to determine the minimum CO2 transport cost from Southern Europe to North Sea sequestration. Different unloading scenarios (port-to-port, port-to-floating storage and injection, and port-to-direct offshore unloading) and carbon reduction targets are investigated. The minimum unitary transport cost is 26 €/t of CO2 for transporting 103 Mt/y
Decarbonization of cement production by electrification
No full textThis study presents the techno-economic assessment of four electrified cement plants: i) using direct electrification and plasma technologies (eC-pK case); ii) consisting of indirect electrification via H2 combustion and oxycombustion of alternative fuels (OC-HK); iii) combining direct electrification, alternative fuels combustion and post-combustion CO2 capture (eC-afK); iv) consisting in the electrification of the hydraulic Calcium Hydro Silicate production process (e-hCHS). Process modeling in Aspen Plus is used to estimate mass and energy balances and calculate techno-economic key performance indicators. The study finds that all the electrified alternatives achieve high levels of equivalent CO2 emissions avoidance (87.2%-101.8%), with a trade-off between the electricity demand (604-1341 kWh/tclk) and the amount of captured CO2 to be handled by the transport & storage infrastructure (357-834 kgCO2/tclk). With an electricity price of 50 euro/MWh, the partially electrified alternatives (OC-HK, eC-afK) showed competitive additional cost of clinker (87 euro/tclk) and cost of avoided CO2 (101 euro/tCO2) against a benchmark case, though higher than the cost of the best CO2 capture technologies from the literature. The eC-pK case resulted in lower economic performance associated mainly to the higher price of electricity per unit of final energy supplied compared to alternative fuels
Improved flexibility and economics of Calcium Looping power plants by thermochemical energy storage
No full textIn this work, a Calcium looping (CaL) system including high temperature sorbent storage is presented, allowing to reduce the size of the calciner and the associated capital-intensive equipment (ASU and CPU). Reduction of the capital costs is particularly important for power plants with low capacity factors, which is becoming increasingly frequent for fossil fuel power plants in electric energy mixes with increasing share of intermittent renewables. The process assessment is performed by: (i) defining pulverized coal power plant (PCPP) with CaL capture system with and without sorbent storage and their mass and energy balances at nominal load; (ii) defining a simple method to predict the performance of the plant at part-load; (iii) defining the economic model, including functions for the estimation of the plant equipment cost; (iv) performing yearly simulations of the systems to calculate yearly electricity production, CO 2 emissions and levelized cost of electricity for different sizes of the calcination line and the storage system and (v) performing sensitivity analysis with different power production plans and carbon taxes. With this process, optimal size of the calciner and of the storage system minimizing the cost of electricity have been found. The optimal plant design was found to correspond to a solids storage system sized to manage the weekly cycling and a calciner line sized on the average weekly load. However, to avoid excessively large solids storage system, sizing the calciner on the average daily load and the storage system to manage the daily cycling appears more feasible from the logistic viewpoint and leads to minor economic penalty compared with the optimal plant design. For the selected case sized on the daily cycling, reduction of the cost of CO 2 avoided between 16% and 26% have been obtained compared to the reference CaL plant without solids storage, for representative medium and low capacity factor scenarios respectively
A Mathematical Tool for Optimising Carbon Capture, Utilisation and Sequestration Plants for e-MeOH Production
No full textCarbon capture, utilisation, and sequestration is key for the decarbonisation of hard-to-abate industries, as it allows avoiding the direct release of CO2 to the atmosphere and generating carbon-based products. However, for these products to be truly carbon-neutral, intermittent renewable electricity must be deployed at scale, leading to the necessity of optimising flexible plants with potential for local buffer storages, geological sequestration, and conversion units. The scope of this work is to provide a mathematical framework for the economic optimisation of a carbon capture, utilisation, and sequestration system, to decarbonise a cement plant located in the Puglia region (Italy), via CO2 geological confinement and/or power and CO2-to-methanol conversion. The final aim is to determine the optimal sizing and cost of the process units of the plant, depending on economic conditions such as the methanol sale price and different perspective costs scenarios. The main outcome is an economic convenience of geological sequestration, as opposed to utilisation, while a long-term scenario would allow for a cost-effective production of methanol when the sale price is above 550 EUR/t
Development of metal/ceramic membranes for hydrogen purification at medium/high temperatures
No full textThe aim of the PhD activity (completely developed at CNR-ICMATE, Padova Research Area) was the development of planar and thin membranes for hydrogen separation for high temperature processes (400°C, metal membranes) and medium temperature processes (< 150°C, zeolite membranes), supported by porous ceramic substrates. Metallic membranes were deposited by PVD processes and zeolite membranes were grown onto ceramic substrate by hydrothermal synthesis. Advantages of PVD techniques are exposed in the PVD chapter of the thesis. PVD deposition is particularly useful in case of metal alloys, since co-sputtering of metals can hinder the inter-metallics formation in the alloy and allows a fine tuning of the chosen stoichiometry.
A goal of the work was to develop new composite membranes combining porous substrates, having fine pore size and smooth surfaces, with a new deposition technique, HiPIMS (High Power Impulse Magnetron Sputtering), to deposit very thin and dense palladium-based membranes (Pd-Ag 77-23 wt%) to reduce the thickness and thus the palladium content, in order to fulfil the targets of the U.S. Department of Energy (DoE), in term of costs of membranes and hydrogen flux.
A further goal of the activity was the investigation of new and promising alloys, mainly palladium-free alloys, with a focus on vanadium based alloys, to meet the new guidelines established by European Community about critical elements. We studied a binary alloy (V90Pd10) and a ternary alloy (V84.2Ni10.5Ti5.3, an alloy whose properties have been predicted by a computational screening approach), both prepared for the first time by PVD processes (the main preparation process involve arc melting).
In order to compare different membranes and flow mechanism, a parallel research activity involved the preparation of thin membranes of zeolites, grown directly onto a porous ceramic substrate. Among the various zeolite structures available, hydroxy-sodalite is the best choice to prepare hydrogen separation membranes, thanks to the pore size compatible with the size of hydrogen molecule. Hydroxy-sodalite membranes are already reported in literature, but our aim was the preparation of reliable zeolite membranes in only one hydrothermal step, simplifying the synthetic approach.
Once membranes were prepared, hydrogen permeation measurements were performed in test station entirely developed at CNR-ICMATE (experimental layout and Labview interface), to gather information about the hydrogen permeance and H2/N2 selectivity of membranes
Analysis of direct carbon fuel cell (DCFC) based coal fired power cycles with CO2 capture
No full textASME GT2012-6977
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