Preliminary design of AR/SOFC cogeneration energy system using livestock waste

Abstract This paper reports on a sizing procedure for integrated Anaerobic Reactor/Solid Oxide Fuel Cell cogeneration energy system powered by livestock waste, in order to meet the provisions of Industry 4.0, connected to the new paradigm of Agriculture 4.0. The algorithm accounts on two main computational blocks, associated to the biogas production plant and to the SOFC energy unit respectively. A numerical modeling is performed to dimension the anaerobic digester and the biogas production deriving, as well as to dimension the energy unit and determine its techno-energy performance when it is fed by the previous biogas. An application of the algorithm is made to a mid-size livestock farm, in order to valorize the biomass waste produced in situ

Demonstration of a kW-scale solid oxide fuel cell-calciner for power generation and production of calcined materials

Carbonate looping (CaL) has been shown to be less energy-intensive when compared to mature carbon capture technologies. Further reduction in the efficiency penalties can be achieved by employing a more efficient source of heat for the calcination process, instead of oxy-fuel combustion. In this study, a kW-scale solid oxide fuel cell (SOFC)-integrated calciner was designed and developed to evaluate the technical feasibility of simultaneously generating power and driving the calcination process using the high-grade heat of the anode off-gas. Such a system can be integrated with CaL systems, or employed as a negative-emission technology, where the calcines are used to capture CO2 from the atmosphere. The demonstration unit consisted of a planar SOFC stack, operating at 750 °C, and a combined afterburner/calciner to combust hydrogen slip from the anode off-gas, and thermally decompose magnesite, dolomite, and limestone. The demonstrator generated up to 2 kWel,DC power, achieved a temperature in the range of 530–550 °C at the inlet of the afterburner, and up to 678 °C in the calciner, which was sufficient to demonstrate full calcination of magnesite, and partial calcination of dolomite. However, in order to achieve the temperature required for calcination of limestone, further scale-up and heat integration are needed. These results confirmed technical feasibility of the SOFC-calciner concept for production of calcined materials either for the market or for direct air capture (DAC)

Sensitivity analysis and process optimization for biomass processing in an integrated gasifier-solid oxide fuel cell system

Hydrogen (H2) production from biomass is always attractive due to its carbon–neutral nature. However, the high energy requirement in biomass gasification and the processing of synthesis gas (syngas) has become the primary concern of the application of this technique. The combined gasifier-solid oxide fuel cell (SOFC) system shows promising potential for significant energy efficiency improvement. However, there is still space to optimize the performance of such combined systems. A novel zero-dimensional (0D) mass-transfer-based model was developed to find the optimal operating parameters for H2 production and to maximize the power density. Coal, sugarcane bagasse, and marine algae were used as feeds to analyze the effects of relevant parameters. A sensitivity analysis of the operational conditions was undertaken to better understand the characteristic trends associated with the maximum power and H2 production. This work optimized the conditions respected with the power density. It was found that the highest power density could be achieved by manipulating operating variables. It is concluded that marine algae have the highest power output but the lowest system efficiency due to high moisture and ash content. Coal produces low power output than biomasses. Hence, sugarcane bagasse is the most efficient feedstock for integrated gasifier-SOFC systems

Technical and economical evaluation of Power-to-Methane technologies, based on green H2 and biogenic CO2

The topic of this PhD thesis is focused on the techno-economic analysis of energy systems for the production of green fuels, such as hydrogen (H2) and biomethane (CH4), exploiting Renewable Energy Sources (RES) and biogenic CO2. In the frame of the Sardinia energy scenario, one of the biggest islands in Italy, the only one without a natural gas grid and, at the same time, a high availability of renewable resources, the present thesis offers a contribution to find a solution for the future decarbonization of the island. The contribution of the present study refers to the production, transport, distribution, and final economic analysis of green fuels to support the energy transition and can also be a model for other isolated energy systems. The analysis carried out allowed the evaluation of the effectiveness and economic feasibility of such innovative technologies, Power-to-Hydrogen and Power-to-Methane. With the focus on the Power-to-Methane system, different layouts have been designed to perform a comprehensive analysis of various solutions. Systems based on commercially mature or innovative technologies are analysed throughout the development of models using MATLAB software. Hydrogen is produced using RES and electric energy from the grid and converted to biomethane through biological methanation processes (BHM), employing the CO2 resulting from the biogas upgrading in anaerobic digestion plants. Two different solutions have been analysed: a BHM process with the injection of CO2 and H2, and a BHM process with the injection of Biogas and H2. Evaluation of the optimal location for the Power-to-Methane system was carried out to find the more profitable way of transporting the CH4 produced. Variations on the reference layout allow getting a comprehensive view of different approaches and integrations, with the common objective to find the solution with the lowest Levelized Cost of Biomethane (LCOBM) value. In addition, another interesting solution studied is the inclusion of a BHM process in a Hydrogen Valley, with a focus on the economic and environmental benefits. Depending on the chosen configuration, the minimum LCOBM was between 2.27 and 2.85 €/Nm3, in the case of polymeric electrolyser membrane technology (PEM) with 56% of energy from RES and alkaline electrolyser (AEL) with 75% of energy from RES, respectively. Finally, including such a system in the Sardinia energy scenario, can provide a contribution of about 44% to the forecast natural gas consumption in 2050

Solid Oxide Fuel Cells: Numerical and Experimental Approaches

Solid oxide fuel cell (SOFC) is a promising electrochemical technology that can produce electrical and thermal power with outstanding efficiencies. A systematic synergetic approach between experimental measurements and modelling theory has proved to be instrumental to evaluate performance and correct behaviour of a chemical process, like the ones occurring in SOFC. For this purpose, starting from SIMFC (SIMulation of Fuel Cells) code set-up by PERT-UNIGE (Process Engineering Research Group) for Molten Carbonate Fuel Cells [1], a new code has been set-up for SOFCs based on local mass, energy, charge and momentum balances. This code takes into account the proper reactions occurring in the SOFC as well as new geometries and kinetics thanks to experiments carried out on single cells and stack in ENEA laboratories of C.R. Casaccia and VTT Fuel Cell Lab in Finland. In particular using an innovative experimental setup it has been possible to study experimentally the influence of a multicomponent mixtures on the performance of SOFC and also validate locally a 2-D model developed starting from SIMFC code. The results obtained are good, showing a good agreement between experimental and numerical results. The obtained results are encouraging further studies which allow the model validation on a greater quantity of data and under a wider range of operating conditions

Process intensification of fuel synthesis and electrolysis

”As more renewable energy is added to the electric grid, energy storage becomes a high priority. Suggestions have been made for energy storage in the form of fuel and chemicals. Currently, Solid Oxide Electrolysis systems can operate in endothermic mode and reduce the electrical requirement by supplying heat. Fuel synthesis from syngas is exothermic and can supply heat. However, the temperature mismatch in the normal operation of the electrolysis step and fuel synthesis step makes the direct utilization of this heat impossible. This work explores possibilities of alternate arrangements of coupling electrochemical systems and chemical synthesis. This work also explores potential for heat integration between the electrolysis and synthesis steps. This is done through exploring higher temperature fuel synthesis systems, and a new intermediate temperature electrolysis system. The successful use of a Mo₂C/HZSM-5 catalyst for ethylene production is shown. Analysis of potential benefits and limitations of each technological approach are examined. The breakeven carbon pricing for the hybrid energy system production of chemicals to be competitive with fossil-fuel based chemical production is calculated”--Abstract, page iii

Carbon capture, utilization, and storage (CCUS) and how to accelerate the development and commercialization of carbon base products in the European and US market

L'abstract è presente nell'allegato / the abstract is in the attachmen