CO2 from direct air capture as carbon feedstock for Fischer-Tropsch chemicals and fuels: Energy and economic analysis

The investigated plant concept integrates the direct air capture technology with the Fischer-Tropsch synthesis. 250 kt/h of air, with a CO2 concentration of 400 ppm, are used as feedstock to produce the synthetic hydrocarbons. The direct air capture is modelled as a high-temperature calcium recovery loop process. An alkaline electrolyser and a reverse water-gas shift reactor produce the required syngas. The Fischer-Tropsch products distribution is described by a carbide model developed for a Co-Pt/ɣAl2O3 catalyst for alkanes and alkenes of carbon number C1-C70. Five integration scenarios are analysed. In the base case, the energy demand of the direct air capture process is supplied with natural gas from the distribution grid. In improved configurations, the effect of Fischer-Tropsch off-gas recirculation to the reverse water-gas shift and/or the direct air capture units is explored, excluding the need of fossil fuel. An electrified direct air capture solution is also included. In the analysed scenarios, the highest system efficiency corresponds to 36.3 %, while the maximum carbon dioxide conversion is of 68.3 %. The maximum waxes production corresponds to 8.7 t/h. Lastly, capital and operating plant costs are allocated in an economic investigation, considering different market electricity costs and financial risk values. In a medium financial risk scenario (interest rate: 7.5 %), the minimum Fischer-Tropsch waxes production cost corresponds to 6.3 €/kgwax, reaching 5.05 €/kgwax at an interest rate of 0%. Lastly, the effect of learning curves over the production cost at the year 2030 and 2050 is included

Energy performance of Power-to-Liquid applications integrating biogas upgrading, reverse water gas shift, solid oxide electrolysis and Fischer-Tropsch technologies

Power-to-liquid (P2L) pathways represent a possible solution for the conversion of carbon dioxide into synthetic value-added products. The present work analyses different power-to-liquid options for the synthesis of Fischer-Tropsch (FT) fuels and chemicals. The FT section is integrated into a complete carbon capture and utilization route. The involved processes are a biogas upgrading unit for CO2 recovery, a reverse water gas shift, a solid oxide electrolyser and a Fischer-Tropsch reactor.The upgrading plant produces about 1 ton/h of carbon dioxide. The recovered CO2 is fed to either a reverse water gas shift reactor or a solid oxide electrolysis unit operating in co-electrolysis mode for the generation of syngas. The produced syngas is fed to a Fischer-Tropsch reactor at 501 K and 25 bar for the synthesis of the Fischer-Tropsch products, which are further separated into different classes based on their boiling point to yield light gas, naphtha, middle distillates, light waxes and heavy waxes. The developed process model uses a detailed carbide kinetic model to describe the formation of paraffins and olefins based on real experimental data. The effect of Fischer-Tropsch off-gas recirculation has been studied against a one-through option. Finally, energy integration of each configuration plant is provided. Results from process simulations show that the best model configurations reach a plant efficiency of 81.1% in the case of solid oxide electrolyser as syngas generator, and 71.8% in the case of reverse water gas shift option, with a global carbon reduction potential of 79.4% and 81.7%, respectively

A GIS Open-Data Co-Simulation Platform for Photovoltaic Integration in Residential Urban Areas

The rising awareness of environmental issues and the increase of renewable energy sources (RES) has led to a shift in energy production toward RES, such as photovoltaic (PV) systems, and toward a distributed generation (DG) model of energy production that requires systems in which energy is generated, stored, and consumed locally. In this work, we present a methodology that integrates geographic information system (GIS)-based PV potential assessment procedures with models for the estimation of both energy generation and consumption profiles. In particular, we have created an innovative infrastructure that co-simulates PV integration on building rooftops together with an analysis of households’ electricity demand. Our model relies on high spatiotemporal resolution and considers both shadowing effects and real-sky conditions for solar radiation estimation. It integrates methodologies to estimate energy demand with a high temporal resolution, accounting for realistic populations with realistic consumption profiles. Such a solution enables concrete recommendations to be drawn in order to promote an understanding of urban energy systems and the integration of RES in the context of future smart cities. The proposed methodology is tested and validated within the municipality of Turin, Italy. For the whole municipality, we estimate both the electricity absorbed from the residential sector (simulating a realistic population) and the electrical energy that could be produced by installing PV systems on buildings’ rooftops (considering two different scenarios, with the former using only the rooftops of residential buildings and the latter using all available rooftops). The capabilities of the platform are explored through an in-depth analysis of the obtained results. Generated power and energy profiles are presented, emphasizing the flexibility of the resolution of the spatial and temporal results. Additional energy indicators are presented for the self-consumption of produced energy and the avoidance of CO2 emission

Ancient pathogen-driven adaptation triggers increased susceptibility to non-celiac wheat sensitivity in present-day European populations

Details of sequence profiles for each NCWS subject. (XLSX 47 kb

"Non vi ha vera storia senza la critica discussione, né discussione critica senza esame delle fonti originali". Gli studi eruditi negli archivi milanesi dall'età napoleonica al primo decennio postunitario

ITALIANO: Il saggio analizza l’atteggiamento tenuto dagli archivisti e dalle autorità pubbliche verso la valorizzazione in chiave storica della documentazione governativa milanese, lungo un arco cronologico che dall’età napoleonica giunge sino alla seconda metà dell’Ottocento. La ricerca si sviluppa in un continuo confronto tra le norme e le prassi in materia di consultazione dei documenti e il contesto politico e culturale nel quale operarono i direttori Luca Peroni, Giuseppe Viglezzi e Luigi Osio. / ENGLISH: The paper analyses the attitude of archivists and public authorities towards the use and appreciation of documents from the government archives of Milan in historical research, from the Napoleonic era to the second half of the nineteenth century. The study unfolds by adopting a constant comparative approach between the rules and practices concerning the consultation of documents and the political and cultural context during the directorships of Luca Peroni, Giuseppe Viglezzi and Luigi Osio

Hydrogen blending into the gas distribution grid: the case study of a small municipality

Hydrogen blending into the gas network may offer an alternative concept for the storage of the exceeding energy from renewable power sources, improving the flexibility of the energy system through the integration of the electricity and gas networks. This scenario foresees the use of electrolyzers to convert power into hydrogen gas. The gas grid could both provide storage and act as the transport facility of the produced gas, taking advantage of the robustness and extensiveness of an already existing energy infrastructure. In this work, a steady state and multi-species thermal-fluid-dynamic model of the gas network is applied to a portion of the Italian distribution network, located in EmiliaRomagna, covering a surface of 2,900 ha and having a throughput of 8.25 MSm3 /year of natural gas. The receiving potential capacity of the existing infrastructure is assessed with respect to hydrogen injection. Fluid-dynamic effects of the hydrogen blending are considered and commented. The maximum allowable percentage of injectable hydrogen is calculated on a nodal basis, referring to the actual gas network configuration. The current Italian regulation on distributed injection (DM 19/02/2007) of gases into the natural gas network only allows injecting gases having nearly the same quality of natural gas (UNI-EN 437), thus excluding any blending practice. However, in the simulated scenario here proposed, it is assumed that gas quality requirements are on the network as a whole (i.e., after blending of hydrogen in the grid) rather than at the single injection point. By exploiting the qualitytracking feature of the model, the constraint of quality assessment at the injection point is thus relaxed. Once the blending limit is known for each node, the amount of injectable hydrogen is calculated accordingly, taking into account the amount of natural gas already flowing through the node itself. The node with the major injection capability is the designated one for the injection and used for the simulation of the case study. Finally, a comparison between the ‘base case’ and the ‘maximum hydrogen injection case’ is presented and discussed showing how hydrogen blending into the gas grid may lead to a reduction on the fossil natural gas supply of up to 2,1%