geometry optimization of a commercial annular rql combustor of a micro gas turbine for use with natural gas and vegetal oils

Abstract A new annular RQL combustion chamber of an 80 kWel Elliott TA80R micro gas turbine was designed and validated by means of CFD simulations of natural gas combustion on modified geometries to overcome known failures at low running hours (around 2500 hrs) caused by overheating. This work provides the results of the design optimization on some geometrical parameters for fuel injection, air-fuel mixing and mixture combustion. Moreover, the new design considered simplified manufacturability and flow optimization to reduce emission while maintaining similar temperatures and efficiencies. The new combustor can easily be built with affordable overall gross costs € guaranteeing similar TIT with respect to the original geometry and with a considerable reduction of NOx emission

Measuring Injectors Fouling in Internal Combustion Engines through Imaging

Abstract The use of liquid fuels derived from biomass in internal combustion engines, based on direct fuel injection, involves the formation of a large amount of carbon deposits on the tip of injectors which significantly influence emissions and engine performance. Currently most of the research activities are focused on the physical and chemical evaluation of deposits, using GC/MS (gas chromatography/mass spectrometry) analysis of alcoholic solutions with dissolved samples and FESEM (Field Emission Scanning Electron Microscopy) and EDS (Energy Dispersive X-ray Spectroscopy) analysis to characterize their microstructures. There are few methodologies to quantify the temporal fouling on the injectors in order to define a correlation between fouling, fuel and engine performance. The development of a methodology to compare the different effects of fouling obtained diversifying the fuel input of a direct injection engine is the aim of this work. The methodology is based on photography and post-processing of images to obtain a pixel count linked to a fouling index. The effect of lighting and visual angle is taken into account and a preliminary qualitative evaluation of the performance of the methodology is carried out. This methodology was also carried out to determine the minimum number of photos required to quantify the deposit independently by the orientation

Development of a tool to optimize economic and environmental feasibility of food waste chains

11 figures, 6 tables.-- Supplementary information available.The Sustainable Development Goal 12.3 focuses on food and its inedible parts that exit the supply chain and thus are lost or wasted. This work addresses the food waste problem by presenting the development of a tool to design business models to reduce the production of food waste. This has been developed within the LIFE16 project iRexfo, coordinated by the University of Perugia. The tool aims at transferring the results obtained in a pilot region (Umbria, Italy) to 4 other regions in Europe. It has been coded in Python and has a graphical user interface (GUI) to insert inputs and display outputs. The GUI has been developed in FLASK and it is hosted in the website of PythonAnywhere. A case study on the application of the software is also presented, mainly based on data retrieved in the Umbria region, Italy. Together with economic analysis, also, environmental assessment is performed.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. i-REXFO LIFE (LIFE16ENV/IT/000547) is a project funded by the EU under the LIFE 2016 program. This work has been partially funded by the GTCLC-NEG project that has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 101018756.Peer reviewe

Evaluation of the effect of pressure and heat transfer on the efficiency of a batch fuel reactor, using Iron-based Oxygen Carrier with a CFD model

19 figures, 4 tables.Coupling a Chemical Looping Combustor fed with biofuels with a turbo expander is a promising Negative Emissions Technology (NET) to realize climate neutral targets in China and Europe. This is also an example of Bioenergy with Carbon Capture and Storage (BECCS) technology. To realize it, we need a Pressurized Chemical Looping Combustion process (PCLC). In this work, a Eulerian-Lagrangian hybrid model is developed in Barracuda-VRTM software, incorporating chemical reactions to predict the performance of a Fuel Reactor using Fe2O3 as oxygen carrier and syngas as fuel, under different pressures, ranging from 1 bar to 20 bars. The model predicted the conversion efficiency of syngas reduction using an iron-based oxygen carrier (Fe2O3/Al2O3). The results show, that the increase in pressure promotes the conversion of CO and inhibits the conversion of H2. When the two gases are considered together, the increase in pressure promotes the reaction between syngas and Fe2O3 and reduces the demand for Fe2O3 oxygen carrier per unit of syngas Lower Heating Value and so also the inventory of the reactor. Increasing temperatures promotes both the reaction of H2 and CO with Fe2O3. Dealing with CO conversion, this is more affected by pressure changes and temperature changes than H2. This represents important information for Fuel Reactor design, scale up and optimization. Further validation is neded in batch and continuous pressurised plants.This work has been funded by the GTCLC-NEG project that has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 101018756.Peer reviewe

Bioenergy with Carbon Capture and Storage (BECCS) developed by coupling a Pressurised Chemical Looping combustor with a turbo expander: How to optimize plant efficiency

18 figures, 6 tables.-- Supplementary information available.Carbon Capture and Storage is a technology of paramount importance for the fulfillment of the Sustainable Development Goal 7 (Affordable and Clean Energy) and the Sustainable Development Goal 5 (Climate Action). The European Union is moving rapidly towards low carbon technologies, for instance via the Energy Union Strategy. Coupling biofuels and carbon capture and storage to decarbonize the power and the industrial sector can be done through the development of BECCS (Bioenergy with Carbon Capture and Storage). Chemical Looping combustion is one of the cheapest way to capture CO2. A Chemical Looping Combustion (CLC) plant can be coupled with a turbo expander to convert energy to power, but it has to work in pressurised conditions. The effect of pressure on the chemical reactions and on fluidised bed hydrodynamics, at the moment, is not completely clear. The aim of this review is to summarize the most important highlights in this field and also provide an original method to optimize power plant efficiency. The main objective of our research is that to design a pressurised Chemical Looping Combustion plant which can be coupled to a turbo expander. To achieve this we need to start from the characteristics of the turbo expander itself (eg. the Turbine Inlet Temperature and the compression ratio) and then design the chemical looping combustor with a top down approach. Once the air and the fuel reactor have been dimensioned and the oxygen carrier inventory and circulation rate have been identified, the paper proposes a final optimization procedure based on two energy balances applied to the two reactors. The results of this work propose an optimization methodology and guidelines to be used for the design of pressurised chemical looping reactors to be coupled with turbo expanders for the production of power with carbon negative emissions.This work has been funded by the GTCLC-NEG project that has received funding from the European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska-Curie grant agreement No. 101018756.Peer reviewe

Food waste anaerobic digestion in Umbria region (Italy): scenario analysis on the use of digestate through LCA

The project irexfo LIFE16 deals mainly with food waste and expired food prevention and reduction, but also with its valorization in biogas plants. Due to legal aspects the cycle of food waste needs to be closed returning the anaerobic digestate to the soil and so providing fertilizer for the cultivation and production of new crops. This is not possible at the moment in Italy because of the Decree of the 25th February 2016 on the disposal of digestate produced from raw materials which are not considered biomasses. The EU Regulation of 2019/1009 of the European Parliament and of the council of the 5th of June 2019, identifies some Component Materials Categories (CMCs), which can be considered as fertilizers; among them we find digestate other than fresh crop digestate, which includes digestate produced from bio-waste and another category on food industry wastes. For this reason, it is meaningful to compare the two possible alternatives: use of food waste digestate as it is in the field and use of food waste digestate after composting it (as currently required by the Italian law)

Due casi di studio: Porta Latina e Castro Pretorio

L’attività qui presentata è una prima sintesi di una ricerca dal titolo: “Le Mura Aureliane: conoscenza, ricognizione, progetto” che coinvolge ricercatori di settori disciplinari diversi del Dipartimento di Architettura dell’Università Roma Tre e prende le mosse da una tesi di laurea Magistrale in Architettura/Restauro discussa presso la Facoltà di Architettura nell’ottobre 2012. Grazie ad un accordo di collaborazione con la Sovraintendenza Capitolina ai Beni Culturali, ed in particolare con l’Unità Operativa “Monumenti di Roma: scavi, restauri, Siti UNESCO” diretta da Francesco Giovanetti, ed al gruppo di lavoro per le “Attività tecnico-scientifiche e valorizzazione dei monumenti archeologici medievali e moderni del suburbio” coordinato da Maria Gabriella Cimino, si stanno sviluppando studi e ricerche volti ad applicare nuovi metodi di rilievo, catalogazione e monitoraggio della Mura al fine della loro conoscenza e conservazione. Il caso di studio è quello di un tratto delle Mura Aureliane lungo circa cento metri lineari presso Porta Latina che comprende, oltre alla porta stessa, le due torri semicircolari (K1 a ovest e J20 ad est) e la torre J19 ad est verso Porta Metronia. Il lavoro è stato strutturato a partire da una campagna di rilevamento tradizionale integrato con il laser scanner 3D che ha permesso di realizzare un modello tridimensionale collegato ad una banca dati sviluppata in ambiente GIS. Le indagini sulla consistenza attuale sono state confrontate con la documentazione storica, sia grafica che descrittiva, consentendo di chiarire alcuni aspetti della storia costruttiva del monumento ancora non sufficientemente definita. La procedura proposta potrà servire da modello per un’attività conoscitiva e pre-progettuale estesa all’intero circuito murario basata su criteri di economicità, precisione, completezza e implementabilità

Le Mura Aureliane: dal rilievo 3D al GIS

Il progredire delle tecnologie digitali ha avuto negli ultimi anni un impatto notevole nelle tradizionali attività di rilievo e documentazione del costruito storico, specialmente quelle svolte in ambito archeologico, grazie all’uso del 3D Survey e dei GIS. Questo è vero soprattutto per lo studio di un monumento imponente e multiforme come quello delle Mura Aureliane, un complesso di dimensioni inusuali (uno sviluppo di quasi 19 km per un volume costruito di oltre 1 milione di metri cubi) con un uso senza soluzione di continuità per oltre 1600 anni, sul quale esiste un’imponente documentazione (cartografica, iconografica, bibliografica, ecc.) non ancora strutturata in un sistema integrato. Questo studio, di cui si presenta una prima sintesi, prende l’avvio dalla ricerca dipartimentale e dalle attività didattiche a cui si è fatto riferimento in un altro intervento al convegno e propone un sistema complessivo di documentazione ed archiviazione delle analisi sull’intero circuito murario, che utilizza le metodologie di 3D Survey e GIS, integrate tra loro, sulla base di alcune esperienze sperimentate nel campo del rilievo archeologico