Solar-Powered Rankine Cycle Assisted by an Innovative Calcium Looping Process as an Energy Storage System

Solar energy is an intermittent resource, and thus an energy storage system is required for practical applications of the collected solar irradiance. This work deals with the integration of a thermo-chemical energy storage (TCES) system based on the calcium looping (CaL) process with a concentrated solar tower power (CSP) plant. The objective of this work is the integration of a conventional 320 MWe Rankine cycle with a direct calcination for energy harvesting. Particularly, this work addresses the use of CO2 as the working fluid of a compressed-gas energy storage (CGES) system for hybrid energy storage with the CaL process. The hybrid TC/CG-ES (thermo-chemical/compressed-gas energy storage) system can increase the competitiveness of the CSP with respect to conventional fossil-based power plants leading to a reduction in CO2 emissions. The thermal integration with the calcium looping (CaL) system is optimized by means of the pinch analysis methodology. The obtained results show a reduction in the electrical efficiency of about four percentage points with respect to the conventional Rankine power cycle without the CSP unit: the net electrical efficiency reduces from 43.7% to 39.5% while the global (thermal and electrical) efficiency of the plant reaches the peak value of 51.5% when low enthalpy energy is recovered (e.g., district heating network, district cooling network). This paper highlights the importance of the thermochemical CaO based material. With a conversion of CaO to CaCO3 of 80% the storage efficiency is defined as the ratio of the energy released during the carbonation and the CO2 expansion to the energy collected by the solar field and required during the CO2 compression, which is 87.3%

Circulating microRNAs found dysregulated in ex-exposed asbestos workers and pleural mesothelioma patients as potential new biomarkers

Malignant pleural mesothelioma (MPM), a fatal cancer, is an occupational disease mostly affecting workers ex-exposed to asbestos fibers. The asbestos, a cancerogenic mineral of different chemical composition, was widely employed in western Countries in industrial manufactures of different types. MPM may arise after a long latency period, up to five decades. MPM is resistant to conventional chemo- and radio-therapies. Altogether, these data indicate that the identification of new and specific markers are of a paramount importance for an early diagnosis and treatment of MPM. In recent years, microRNAs expression was found dysregulated in patients, both in cancer cells and sera, affected by tumors of different histotypes, including MPM. Cell and circulanting microRNAs, found to be dysregulated in this neoplasia, were proposed as new biomarkers. It has been reported that circulating microRNAs are stable in biological fluids and could be employed as potential MPM biomarkers. In this investigation, circulating microRNAs (miR) from serum samples of MPM patients and workers ex-exposed to asbestos fibers (WEA) and healthy subjects (HS) were comparatively analyzed by microarray and RT-qPCR technologies. Our results allowed (i) to select MiR-3665, an endogenous stable microRNA, as the internal control to quantify in our analyses circulating miRNAs; to detect (ii) miR-197-3p, miR-1281 and miR 32-3p up-regulated in MPM compared to HS; (iii) miR-197-3p and miR-32-3p up-regulated in MPM compared to WEA; (iv) miR-1281 up-regulated in both MPM and WEA compared to HS. In conclusion, three circulating up-regulated microRNAs, i.e. miR-197-3p, miR-1281 and miR-32-3p are proposed as potential new MPM biomarker

Sorption enhanced steam methane reforming in a bubbling fluidized bed reactor: Simulation and analysis by the CPFD method

This work reports the modelling and simulation results of a bubbling fluidized bed reactor using the Computational Particle Fluid Dynamics (CPFD) method of the Barracuda® software. The reactor under investigation is the carbonator installed in the ENEA ZECOMIX research infrastructure, where Steam Methane Reforming (SMR) happens simultaneous with CO2 capture via solid sorbents. In this intensified process, namely Sorption Enhanced Steam Methane Reforming (SE-SMR), steam methane reforming is coupled with high temperature CO2 sorption and calcium looping (CaL) process, in order to increase the H2 yield, beyond thermodynamic limits. Currently, the reactor is operated in batch mode and is used also for sorbent regeneration, by switching the fluidizing gas flow from steam/methane to oxy-burner combustion products. With the aim of studying the process when it is operated as a closed loop, in this paper the reactor is continuously fed by a fresh sorbent flow and a riser/calciner reactor for sorbent regeneration, to be connected with the carbonator, has been sized. The continuous circulation of solid material between the two reactors ensures the maintenance of different operating temperatures and therefore greater operational optimization. The numerical analysis presented in this paper will serve as a valid support for the experimental activities. For this purpose, a sensitivity study on the SE-SMR process has been conducted, by varying the main operating conditions (e.g. sorbent conversion, sorbent/catalyst ratio, fluidizing gas flow), to evaluate the hydrogen purity yield. Two different kinetic mechanisms have been compared for the gas phase reactions. A post-processing routine has been written, in order to analyze bubbles sizes and velocities inside the fluidized environment. The effect of sorbent and catalyst particles segregation has been also investigated. The same modelling approach has been used for the sizing of the fast riser calciner reactor

A water cooled, high power, dielectric barrier discharge reactor for CO2 plasma dissociation and valorization studies

Aiming at the energy efficient use and valorization of carbon dioxide in the framework of decarbonization studies and hydrogen research, a novel dielectric barrier discharge (DBD) reactor has been designed, constructed and developed. This test rig with water cooled electrodes is capable of a plasma power tunable in a wide range from 20W to 2 kW per unit. The reactor was designed to be ready for catalysts and membrane integration aiming at a broad range plasma conditions and processes, including low to moderate high pressures (0.05–2 bar). In this paper, preliminary studies on the highly endothermic dissociation of CO2, into O2 and CO, in a pure, inert, and noble gas mixture flow are presented. These initial experiments were performed in a geometry with a 3 mm plasma gap in a chamber volume of 40cm3, where the process pressure was varied from few 200 mbar to 1 bar, using pure CO2, and diluted in N2. Initial results confirmed the well-known trade-off between conversion rate (up to 60%) and energy efficiency (up to 35%) into the dissociation products, as measured downstream of the reactor system. Improving conversion rate, energy efficiency and the trade-off curve can be further accomplished by tuning the plasma operating parameters (e.g. the gas flow and system geometry). It was found that the combination of a high-power, water-cooled plasma reactor, together with electronic and waveform diagnostic, optical emission and mass spectroscopies provides a convenient experimental framework for studies on the chemical storage of fast electric power transients and surges

Realizzazione di un impianto di pirolisi e gassificazione di combustibili solidi per la produzione di syngas ad alto contenuto di idrogeno e basso impatto ambientale

Il presente documento costituisce una prima bozza di studio progettuale relativo ad un impianto di trattamento termico per combustibili solidi con particolare attenzione all’utilizzo del carbone, con una tecnologia combinata di pirolisi (tamburo rotante) e gassificazione (letto fluido). Scopo dell’impianto è fornire informazioni utili all’approfondimento delle tematiche scientifiche affrontate nella piattaforma Zecomix, nei processi di gassificazione e carbonatazione con utilizzo di diverse tipologie di carbone e di reagenti e/o catalizzatori. Sarà inoltre utilizzato come ‘test rig’ per lo studio di un ciclo integrato pirolisi/gassificazione/combustione per l’ottimizzazione della produzione di syngas ad alto contenuto di idrogeno da carbone, a basso impatto ambientale. L’impianto denominato VAL.CH.I.RI.A (VALorizzazione CHar, Impianto RIcerche Avanzate) sarà costituito dai componenti minimi rappresentati nel P&I allegato e parte integrante del presente studio. La versatilità dell’impianto permetterà l’utilizzo dello stesso anche studiando il comportamento di combustibili non convenzionali come biomasse e miscele carbone /biomasse. Sarà inoltre possibile utilizzare i vari componenti in modo separato ed in modo integrato come riportato di seguito: - alimentazione – pirolisi – torcia; - alimentazione – gassificazione – torcia; - alimentazione – pirolisi – gassificazione – torcia. La pressione di esercizio sarà prossima a quella atmosferica per facilitare la esecuzione delle prove e la realizzazione strutturale della componentistica. Esso verrà realizzato presso il Centro Ricerche ENEA Casaccia in prossimità della piattaforma Zecomix e, al fine di ottimizzare il suo utilizzo, verrà costruito su skid di facile allocazione e spostamento in loco

Modeling and Simulation of an Oxygen-Blown Bubbling Fluidized Bed Gasifier using the Computational Particle-Fluid Dynamics (CPFD) Approach

Fluidized beds are conventional components of many industrial processes, such as coal gasification for energy generation and syngas production. Numerical simulations help to properly design and understand the complex multiphase flows occurring in these reactors. Two modeling approaches are usually adopted to simulate multiphase flows: the two fluids Eulerian-Eulerian model and the continuous/discrete Eulerian-Lagrangian model. Since fluidized beds account for an extremely large number of particles, tracking each of them could not assure to get results within a reasonable computational time. The Computational Particle-Fluid Dynamics (CPFD) approach, which belongs to the Eulerian-Lagrangian models class, groups together particles with similar key parameters (e.g. composition, size) into computational units (parcels). Parcel collisions are modeled by an isotropic solid stress function, depending on solid volume fraction. In this paper, the bubbling fluidized bed (BFB) upstream gasifier of the EU research infrastructure ZECOMIX (Zero Emissions of Carbon with Mixed technologies) has been simulated using a CPFD approach via Barracuda® software. The effect of different fluidizing agent injection strategies on bed bubbling and mixing, for non-reacting cases, has been studied. The numerical results for a reacting case have been compared to the available experimental data, gathered during the coal gasification campaign. The model has proved to be very useful in the choice of the more efficient injection configuration that assures a more effective contact of the gas with the solid bed and a good bubbling fluidization regime, together with a satisfactory prediction of the outlet gas composition. The numerical approach has turned out to be robust and time-saving and allowed to dramatically reduce the computational cost with respect the classical two fluids Eulerian-Eulerian models

One-pot synthesis of ni0.05 ce0.95 o2−δ catalysts with nanocubes and nanorods morphology for co2 methanation reaction and in operando drift analysis of intermediate species

The valorization of CO2 via renewable energy sources allows one to obtain carbon-neutral fuels through its hydrogenation, like methane. In this study, Ni0.05 Ce0.95 O2−δ catalysts were prepared using a simple one-pot hydrothermal method yielding nanorod and nanocube particles to be used for the methanation reaction. Samples were characterized by XRD, BET, TEM, H2-TPR, and H2-TPD experiments. The catalytic activity tests revealed that the best performing catalyst was Ni0.05 Ce0.95 O2−δ, with nanorod morphology, which gave a CO2 conversion of 40% with a selectivity of CH4 as high as 93%, operating at 325◦ C and a GHSV of 240,000 cm3 h−1 g−1 . However, the lower activation energy was found for Ni0.05 Ce0.95 O2−δ catalysts with nanocube morphology. Furthermore, an in operando diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analysis was performed flowing CO2:H2 or CO:H2 mixture, showing that the main reaction pathway, for the CO2 methanation, is the direct hydrogenation of formate intermediate

Antifibrotic treatment response and prognostic predictors in patients with idiopathic pulmonary fibrosis and exposed to occupational dust

BACKGROUND: Idiopathic Pulmonary Fibrosis (IPF) is an aggressive interstitial lung disease with an unpredictable course. Occupational dust exposure may contribute to IPF onset, but its impact on antifibrotic treatment and disease prognosis is still unknown. We evaluated clinical characteristics, respiratory function and prognostic predictors at diagnosis and at 12 month treatment of pirfenidone or nintedanib in IPF patients according to occupational dust exposure. METHODS: A total of 115 IPF patients were recruited. At diagnosis, we collected demographic, clinical characteristics, occupational history. Pulmonary function tests were performed and two prognostic indices [Gender, Age, Physiology (GAP) and Composite Physiologic Index (CPI)] calculated, both at diagnosis and after the 12 month treatment. The date of long-term oxygen therapy (LTOT) initiation was recorded during the entire follow-up (mean = 37.85, range 12-60 months). RESULTS: At baseline, patients exposed to occupational dust [≥ 10 years (n = 62)] showed a lower percentage of graduates (19.3% vs 54.7%; p = 0.04) and a higher percentage of asbestos exposure (46.8% vs 18.9%; p 0.002) than patients not exposed [< 10 years (n = 53)]. Both at diagnosis and after 12 months of antifibrotics, no significant differences for respiratory function and prognostic predictors were found. The multivariate analysis confirmed that occupational dust exposure did not affect neither FVC and DLCO after 12 month therapy nor the timing of LTOT initiation. CONCLUSION: Occupational dust exposure lasting 10 years or more does not seem to influence the therapeutic effects of antifibrotics and the prognostic predictors in patients with IPF

Avviamento del gassificatore della piattaforma Zecomix: fluidizzazione della fase di sostegno

Nel presente lavoro vengono riportate i primi risultati sperimentali ottenuti dalla piattaforma sperimentale Zecomix. È stata proposta una procedura di start-up del gassificatore che ha consentito di definire le grandezze operative principali: portata di carbone, portata della fase di sostegno, velocità di fluidizzazione del letto, temperatura di ingresso dell’agente fluidizzante. Il raggiungimento di un buon grado di fluidizzazione consente un alto grado di combustione e gassificazione del carbone alimentato. A tal fine è stata calcolata la portata di aria affinché il materiale di sostegno scelto (olivina) raggiunga un buon grado di fluidizzazione, u=2.5umf, durante la combustione e gassificazione ad una temperatura di 800 °C. I risultati ottenuti sulle prime prove di fluidizzazione, in accordo con quanto previsto dalla teoria, mostrano che nel letto si è instaura un buon regime di fluidizzazione necessario per la contemporanea combustione e gassificazione del carbone in condizioni di ‘autotermicità’. Per minimizzare il consumo del combustibile ausiliario (metano) è stata fatta la scelta operativa di aggiungere durante il warm-up del gassificatore, il 10% in massa di carbone e poi gradualmente aumentare l’alimentazione di combustibile fino al valore stechiometrico. In questa fase, si è notato come l’aumento della temperatura dell’aria di fluidizzazione Tf è un indice dell’aumento della temperatura media all’interno del gassificatore. La temperatura Tf, infatti, cresce principalmente, grazie alla presenza di uno scambiatore di calore economizzatore che trasferisce il calore sensibile del gas all’uscita del gassificatore e l’aria di fluidizzazione. Il principale risultato ottenuto durante le prove di avviamento del reattore mostra come per ottenere un buon grado di fluidizzazione la temperatura di ingresso dell’aria di fluidizzazione Tf debba raggiungere un plateau tra 300 °C e 350 °C. Tenuto conto di questo importante risultato, il bilancio di energia del gassificatore consente di determinarne l’Equivalence Ratio (ER) necessario per il calcolo sia della portata di vapore che di quella dell’ossigeno durante la gassificazione del carbone. Il bruciatore ausiliario è posto al di sopra della superficie del letto in modo che quando il letto è fluidizzato i solidi vengono in contatto con il fronte di fiamma e vengono riscaldati. Quindi è necessario sapere la quantità di olivina che bisogna caricare e quindi l’altezza del letto quando questo risulta fluidizzato. Da un bilancio di forze risulta che l’altezza del letto durante lo start-up, T=500 °C, e durante la gassificazione rimane circa costante a 67 cm. In seguito grazie all’elevata capacità termica dell’olivina così riscaldata è possibile raggiungere la temperatura operativa con un supporto minimo, o nullo, da parte del bruciatore di start-up. Sono necessarie dalle 3 alle 5 ore per portare il letto da temperatura ambiente alla temperatura di 500 °C-600°C. Il risultato principale delle prove di fluidizzazione è che l’istaurarsi del regime di fluidizzazione l‘eye-on-the-process’ è sulla temperatura al di sopra della griglia e la temperatura di ingresso dell’aria di fluidizzazione