1,721,056 research outputs found
A Circular Approach for Making Fischer–Tropsch E-fuels and E-chemicals From Biogas Plants in Europe
Full text linkIn a mature circular economy model of carbon material, no fossil compound is extracted from the underground. Hence, the C1 molecule from non-fossil sources such as biogas, biomass, or carbon dioxide captured from the air represents the raw material to produce various value-added products through carbon capture and utilization routes. Accordingly, the present work investigates the utilization of the full potential of biogas and digestate waste streams derived from anaerobic digestion processes available at the European level to generate synthetic Fischer–Tropsch products focusing on the wax fraction. This study estimates a total amount of available carbon dioxide of 33.9 MtCO2/y from the two above-mentioned sources. Of this potential, 10.95 MtCO2/y is ready-to-use as separated CO2 from operating biogas-upgrading plants. Similarly, the total amount of ready-to-use wet digestate corresponds to 29.1 Mtdig/y. Moreover, the potential out-take of Fischer–Tropsch feedstock was evaluated based on process model results. Utilizing the full biogas plants’ carbon potential available in Europe, a total of 10.1 Mt/h of Fischer–Tropsch fuels and 3.86 Mt/h of Fischer–Tropsch waxes can be produced, covering up to 79% of the global wax demand. Utilizing only the streams derived from biomethane plants (installed in Europe), 136 ton/h of FT liquids and 48 ton/h of FT wax can be generated, corresponding to about 8% of the global wax demand. Finally, optimal locations for cost-effective Fischer–Tropsch wax production were also identified
Dynamic modeling and thermal management of a Power-to-Power system with hydrogen storage in microporous adsorbent materials
No full textThe increasing penetration of distributed renewable energy sources involves the development of efficient energy storage solutions. Hydrogen is a viable alternative, or complement, to electric batteries for long-term and high-capacity storage. This article assesses the benefits of hydrogen storage in microporous adsorption materials at room temperature. The integrated Power-to-Power system dynamic behavior is modelled. We assessed the system performance looking at hydrogen adsorption in four porous materials (MSC-30, IRMOF-1, NU-110, and C/Be2) at room temperature for high-storage capacity. Hydrogen storage in an empty pressurized vessel by means of mechanical compression only is evaluated for comparison of the previous cases. The best performance in terms of tank volume size and round-trip efficiency are obtained by adopting adsorbent materials as follows: C/Be2 > IRMOF-1 > NU-110 > MSC-30 > empty storage. Indeed, under the same operating conditions, the volume size of the storage tank is reduced by 38 to 88% compared to the empty vessel, and the round-trip efficiency gain ranges between 0.6 and 2.8 percentage points according to the properties of the adsorbent material. Finally, by filling the storage tank with adsorbent materials the DOE targets are met at a pressure from 45% (MSC-30) to 83% (C/Be2) lower than in an empty tank
Solar-Powered Rankine Cycle Assisted by an Innovative Calcium Looping Process as an Energy Storage System
Full text linkSolar 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%
Energy and environmental analysis of a flexible Power-to-X plant based on Reversible Solid Oxide Cells (rSOCs) for an urban district
Full text linkThis study proposes the modeling and the performance assessment of a grid-connected Reversible Solid Oxide Cell (rSOC) plant that is the core system of a polygeneration flexible hub between the national electric grid and the local microgrid of an urban residential district. The system is designed to integrate a thermal storage unit based on phase change material with the rSOC stack by mzedeans of heat pipes. At times of low electricity price, the plant produces hydrogen via electrolysis fed preferentially by a dedicated wind farm. Hydrogen is stored as compressed gas and used for the public transportation and electricity production during peak-demand hours. The goal of the study is to investigate the performance and environmental indicators of this novel rSOC configuration and to identify which operating strategy best fits with the analyzed district application. The operating points of the overall system are mapped with a steady-state model and interfaced with thermal storage and loads by a time-resolved dynamic model. The feasible schedules of the system are defined considering the rSOC switching dynamics between fuel cell and electrolysis, and constraints on plant self-sufficiency for both heat and hydrogen vectors. Simulations at different levels of hydrogen demand for mobility (ranging between 10 and 1,000 ton/year) were performed. Results showed an annual efficiency range of 55–70% (including heat to DH) of the polygeneration plant. The environmental analysis showed that the rSOC plant emits 5–50% less CO2 than the current energy system (gas boilers, grid electricity, diesel buses), when electrolysis is fed by grid-electricity with the present UK carbon intensity in case of wind power shortages
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Prevalence and risk factors for Helicobacter Pylori (HP) infection in a recently developed area in northern Italy.
No full textItalian Journal of Gastroenterology 1995; 27 Suppl. 1: 99-100
Hepatitis A infection in a recently industrialized rural region: seroprevalence and relationship with socio-economic conditions.
No full textERYTHROCYTE POTASSIUM CONTENT AND ACID-BASE-EQUILIBRIUM IN PATIENTS WITH HEPATIC CIRRHOSIS - EFFECT OF ORAL POTASSIUM-CHLORIDE ADMINISTRATION
No full textTowards Near-zero Energy Buildings: Lessons Learnt from the RE-cognition project
No full textThe building sector is accountable for the 40% of the energy consumed and 36% of carbon emissions in the EU. At the same time, ambitious energy targets are required for a substantial reduction of greenhouse gas emissions in the forthcoming years. To tackle this challenge, a possible approach consists in boosting the adoption of Renewable Energy Sources (RES) at the places where energy is consumed (decentralized approach), minimizing carbon emissions. Hence, the path towards near-zero Energy Buildings (nZEBs) is regarded as one of the most viable solutions to meet the de-carbonization goal. However, a certain technological and policy-driven push is required for improving the actual inefficient European building stock. In this context, the RE-cognition project proposes an ICT (information and communications technologies) integration framework on top of established and ad-hoc designed renewable energy technologies. This paper presents how such an integration framework can be applied to a real building. The case study is a facility located in Turin, Italy, known as Energy Center, where companies, public administration and university researchers are hosted. Here, the existing photovoltaic system (PV), ground-source heat pump (GSHP) and district heating substation (DH) are coupled with a newly developed Latent Heat Thermal Storage (LHTS) and an innovative micro turbine for the cogeneration of heat and power (m-CHP). Results discuss the insights gained in advancing this pilot site towards an effective near-zero Energy Building
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