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![Energy densities of ammonia and other common fuels [5].](publication/347258594/figure/tbl1/AS:1023071926374401@1620930763102/Energy-densities-of-ammonia-and-other-common-fuels-5.png)
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Ammonia has strong potentialities as sustainable fuel for energy applications. NH3 is carbon free and can be synthetized from renewable energy sources (RES). In Solid Oxide Fuel Cells, NH3 reacts electrochemically thereby avoiding the production of typical combustion pollutants such as NOx. In this study, an ammonia-fueled solid oxide fuel cells (S...
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... ammonia is produced from natural gas but a pathway for the production of green ammonia can be designed based on hydrogen from electrolysis or biogas [3,4]. Table 1 compares ammonia with the most common fuels. Ammonia is characterized by a volumetric energy density significantly higher than compressed natural gas at 250 bar, with gravimetric energy density more than halved with respect to fossil fuels but greater than methanol. ...Context 2
... BOR was set to one, meaning that all the air coming from the cathode outlet goes into the after burner. The ADR approach was fixed to 20 • C. Table 10 reports main results of the system operation under nominal condition. The stack energy balance requires an oxygen use of 0.17, corresponding to a specific air flow rate of 2.93 Nl h −1 cm FC −2 . ...Context 3
... lambda of the after burner is 9.78, as a consequence of flowing all cathodic exhausts into the after burner. Table 11 reports gas compositions for all pipes. Please note that hydrogen is completely oxidized in the after burner and off-gases contain only oxygen, nitrogen, and water (steam). ...Context 4
... LCOE, according to the procedure detailed in Section 2.3, results in 0.221 $ kWh −1 for nominal design conditions. The capital cost of each component and relative quote for a 100 kW system is reported in Table 14. The most significant share of the cost fall in the stack and in the inverter. ...Context 5
... most significant share of the cost fall in the stack and in the inverter. It is notable that low temperature heat exchange has a much higher cost that the high temperature one due to the higher exchange area required to complete heat transfer at lower temperature (see aHE values in Table 12). ...Context 6
... LCOE, according to the procedure detailed in Section 2.3, results in 0.221 $ kWh −1 for nominal design conditions. The capital cost of each component and relative quote for a 100 kW system is reported in Table 14. The most significant share of the cost fall in the stack and in the inverter. ...Context 7
... most significant share of the cost fall in the stack and in the inverter. It is notable that low temperature heat exchange has a much higher cost that the high temperature one due to the higher exchange area required to complete heat transfer at lower temperature (see a HE values in Table 12). TOT 94,790.50 ...Similar publications
An increasing demand in the marine industry to reduce emissions led to investigations into more efficient power conversion using fuels with sustainable production pathways. Solid Oxide Fuel Cells (SOFCs) are under consideration for long-range shipping, because of its high efficiency, low pollutant emissions, and fuel flexibility. SOFC systems also...
Citations
... The operational and maintenance costs were taken as 18.7% of the total initial investment. 48 The formula to calculate the electric work from the SOFC is dened in eqn (2). 49 ...
... h represents the energy conversion efficiency of the SOFC, which is approximately 52.1%. 48 The term _ m is the mass ow rate of ammonia coming into the system, and LHV is the low heating value of ammonia, which is 18.7 MJ kg −1 . 50 _ W out is the power output from the fuel cell. ...
A techno-economic assessment was carried out for a novel system that combines anaerobic digestion, electrodialysis, electrochemical ammonia stripping, vacuum membrane distillation, and a direct ammonia-fed solid oxide fuel cell to generate electricity from sewage treatment. Traditional wastewater treatment systems focus primarily on removing contaminants with limited resource recovery opportunities. The current study presented an innovative wastewater treatment system designed to address the limitations of conventional plants. An assessment was performed to determine the scalability of the proposed system to effectively produce ammonia from municipal wastewater, which can be further used for electricity generation. The levelized costs of ammonia (LCOA) and electricity (LCOE) were determined along with the net present value, payback period, return on investment and benefit-cost ratio. Detailed evaluations of the cost and performance of each processing unit indicated that long-term cost savings can be achieved despite substantial initial capital investment. The proposed system can produce ammonia at 0.11 Mt per year, which can further generate around 254.58 GWh of electricity per year. The findings demonstrated that at a discount rate of 5% and assuming plant life to be 25 years, LCOA and LCOE were estimated at US 0.16 per kWh of electricity, respectively. A sensitivity analysis was conducted by varying the discount rate (0–20%), which demonstrated that ammonia production was comparatively more financially stable at high discount rates under a certain threshold. The study provided a model for modern wastewater treatment plants aiming for energy neutrality and resource recovery, aligning with global sustainability goals. Future research can explore renewable energy integration with the assessed system to sustain long-term operations.
... In 2018, Perna et al. 79 developed an ammonia-based CHP system that incorporated an ammonia fuel cell, a hydrogen separator from exhaust gases, and hydrogen compression and storage to yield heat, power, and hydrogen. In 2020, Barelli et al. 80 presented a contemporary concept and design for an NH 3 −SOFC system consisting of six cells, performing thermodynamic analyses to evaluate its viability. These studies and experiments underscore the potential of NH 3 SOFC technology for portable energy systems ( Table 2; however, significant efforts are still required to bring this technology to commercial viability. ...
Conventional technologies primarily powered by fossil fuels have led to significant environmental issues. Hydrogen, which is a carbon-free fuel, has emerged as a substantial energy sector in recent years. However, challenges related to its storage and long-distance transportation remain obstacles to its widespread use. Conversely, with its superior energy density (12.9 MJ L −1) compared to hydrogen (5.6 MJ L −1), ammonia is more amenable to transport and offers a CO 2-free alternative that is versatile enough for various power generation systems. In this context, solid oxide fuel cell (SOFC) technology stands out as an effective solution for directly converting ammonia into electrical energy with high efficiency. However, the progress of this technology is hampered by the sluggish kinetics of the chemical and electrochemical processes occurring at the anodes and catalysts, limiting its commercialization. This review covers the fundamental principles, thermodynamics, and kinetics of the ammonia dissociation reaction, offering a comprehensive overview of how these factors influence the electrochemical performance and long-term durability of direct ammonia fuel cells at both the single-cell and stack levels. Furthermore, it provides critical insights for improving performance and mechanistic understanding while establishing a conceptual framework for the design of electrodes for ammonia-powered SOFC.
... Based on these indications, this work assumes full conversion of ammonia in the cracking unit, with only trace levels of ammonia present in the outlet stream, consistent with assumptions made in other energy studies. 17,[47][48][49]57 The reactor representing the FC is modeled as an R-STOIC reactor, where the reaction and the corresponding conversion are explicitly defined. 51 This reactor simulates the reaction between hydrogen and oxygen to produce water and generate energy. ...
In the context of the near-future hydrogen economy, ammonia is regarded as one of the most promising hydrogen carriers in the short-to-medium term. As part of the broader transition to a new energy paradigm, the well-established and extensive ammonia infrastructure can serve as a platform for green hydrogen transportation, storage, and utilization. This study analyzes various process configurations integrated with different types of fuel cells for ammonia utilization through Aspen Plus simulations. The evaluation focuses on overall energetic efficiency (ranging from 31.20 to 51.50% depending on the adopted configuration), autothermality (42.00 to 100.00%, based on the adopted process configuration), and emissions from external heat sources (0.03–0.07 kgCO2/kWh). Assessments are conducted parametrically across different fuel cell efficiencies (50.0–65.0%). Results suggest that high-temperature PEMFC and direct ammonia solid oxide fuel cells (SOFCs) offer a balance between overall efficiency (40.2–51.5 and 35.00–52.0%, respectively) and feasibility of achieving autothermal operations under nitrogen dilution (up to 25.0%). Considering technological maturity and operational lifespan, high-temperature PEMFCs and SOFCs emerge as a promising component for such integrated systems.
... As all energy projects aim to reduce the cost of energy production, the value of the localized cost of energy (LCOE) is estimated to compare between the two proposed systems, with reference to the specific unit of energy, as shown in Eq.18. LCOE is a measure of the average net present cost of electricity produced from a specific energy source over its lifetime [18,66,67]: ...
The maritime industry is actively seeking sustainable solutions to reduce ship emissions and enhance energy efficiency. This study explores the use of alternative fuels and renewable energy sources, focusing on the potential environmental and economic benefits of combining natural gas (NG) fuel with Flettner rotor (FR) technology. The research employs technical, environmental, and economic models to evaluate various scenarios integrating NG fuel with FR in alternative propulsion systems. It investigates three propulsion configurations for LNG vessels: diesel engine (DE-FR), dual fuel diesel engine (DFE-FR), and combined gas and steam turbine engines (COGAS-FR). Results indicate that utilizing six Flettner rotors produces 1.254 MW, resulting in fuel savings of 3.49% to 4.49%, along with notable emission reductions. The COGAS-FR system emerges as the most environmentally friendly option, enhancing energy efficiency by 4.68% based on current ship standards. From an economic perspective, transitioning to the DFE-FR system is identified as an optimal eco-friendly choice, leading to a 9.85% reduction in the levelized energy cost compared to DE-FR. However, it is noteworthy that the COGAS-FR system has the most significant environmental impact, with a cost-effectiveness of $10,954.6 per ton.
... Lastly, the voltage is (11), where for the OCV, the Nernst voltage was used. ASR is the area-specific resistance and K is a parameter that considers the impact of Uf in the performances based on experimental results-as evidenced in previous experimental work [38]. ...
Biogas presents a renewable fuel source with substantial potential for reducing carbon emissions in the energy sector. Exploring this potential in the farming sector is crucial for fostering the development of small-scale distributed biogas facilities, leveraging indigenous resources while enhancing energy efficiency. The establishment of distributed biogas plants bolsters the proportion of renewable energy in the energy matrix, necessitating efficient power generation technologies. Given their proximity to bio-waste production sites like farms and digesters, optimising combined heat and power generation systems is imperative for energy self-sufficiency. Small-scale biogas facilities demand specific power generation technologies capable of achieving notable efficiencies, ranging from 40% to 55%. This study focuses on employing Solid Oxide Fuel Cells (SOFCs) in biogas-to-power systems and investigates the theoretical operation of SOFCs with fuel mixtures resulting from different biogas lean upgrading pathways. Therefore, starting from ten mixtures including CH4, CO2, H2, H2O, N2, and O2, the study proposes a method to assess their impact on the electrochemical performance, degradation, and energy equilibrium of SOFC units. The model embeds thermodynamic equilibrium, the Nernst potential, and energy balance, enabling a comprehensive comparison across these three analytical domains. The findings underscore the unsuitability of dry biogas and dry biomethane due to the potential risk of carbon deposition. Moreover, mixtures incorporating CO2, with or without H2, present significant thermal balance challenges.
... A high efficient and environmentally friendly energy converter for fuels with relatively high volumetric energy densities such as liquid hydrocarbons or ammonia is needed. An energy converter with promising high efficiencies and no NOx emissions even for ammonia utilization [17] is the solid oxide fuel cell (SOFC). The SOFC has a high fuel flexibility and is able to utilize hydrogen, ammonia, and hydrocarbons with high electrical efficiencies [18][19][20]. ...
The high volumetric energy density and easy storage capability of liquid hydrocarbons such as bio-diesel or diesel are needed for power generation in several applications such as ships and isolated or rural areas which only have limited access to other power grids. Solid oxide fuel cells (SOFCs) can in theory utilize such fuels in a high efficient manner, which could reduce greenhouse gas emissions and energy demand. However, SOFC systems able to directly utilize diesel are rather complex to design and monitor, leading to several possible causes of system lifetime reduction. To avoid an enhanced reduction of the system lifetime, the operating conditions of all components must be optimized and monitored in detail. However, detailed monitoring and identification of the cause of performance loss are challenging using conventional system monitoring methods. Therefore, here we (i) show the concept and characterization of a SOFC system operating under steam-and auto-thermal diesel reforming conditions, (ii) demonstrated the applicability of advanced methods to monitor complex SOFC systems, which are applied on the 30 cell SOFC stack during system operation and (iii) analyzed the efficiency potential of the SOFC within the developed system. The results present in this work are favorable to accelerate commercialization.
... This has the benefit of simplifying the fuel infrastructure. Ammonia is also becoming a deeply investigated topic by the scientific community [85][86][87]. ...
Solid oxide fuel cell (SOFC) systems are spreading worldwide and, for limited applications, also in the transport sector where high power rates are required. In this context, this paper investigates the performance of a six-cell SOFC stack by means of experimental tests at different power levels. The experimental campaign is based on two different stages: the heating phase, useful for leading the system temperature to approximately 750 °C, and the test stage, in which the experimental activities are properly carried out with varying input parameters, such as the DC current load. In addition, a detailed post-processing activity is conducted to investigate the main performance that could be used in the scale-up processes to design and size a SOFC-based system for transportation. The experimental results concern the electrical power, which reaches 165 W, roughly 27 W for each cell and with 52% electrical efficiency, as well as the theoretical thermal power and efficiency, useful for cogeneration processes, with maximum values of 80 W and 25%, respectively, achieved at maximum load. This discussion then shifts to an in-depth analysis of the possible applications of SOFCs in sustainable mobility, particularly in the maritime and aviation industries. The complexities of the issues presented underscore the field’s multidisciplinary nature, ranging from materials science to system integration, and environmental science to regulatory standards. The findings presented could be useful to scientists, engineers, policymakers, and industry stakeholders working on the development and commercialization of SOFC systems in the sustainable transportation sectors.
... In vehicles using ammonia combustion, NO X emissions range from 0 to 6 ppm, depending on the combustion temperature and catalyst used [158]. With the technology of using ammonia as a fuel for fuel cells, there are no emissions of nitrogen oxides [143]. This type of technology would be more beneficial in terms of reducing NO X in the atmosphere. ...
... In the case of using a dual-fuel compression ignition engine with ammonia and diesel, the concentration of unburned ammonia in wet exhaust ranged from 7 ppm for the diesel-only case to 14,800 ppm for the maximum contribution of ammonia energy (84.2% of the energy input) [164]. Using solid oxide fuel cells, ammonia emissions have been observed in the range of 40-250 ppm [143]. It is important to note that SOFC-based systems typically use an additional post-reaction gas afterburner, such as a catalytic burner, where the ammonia can further decompose. ...
The main purpose of the article is to present a comprehensive and critical review of the challenges and risks associated with the use of green ammonia as an alternative fuel in land transport. The review is motivated by the clear trend toward phasing out fossil fuel vehicles and replacing them with emission-free alternatives. Topics covered include safety aspects such as safety of powering of vehicles, the production of green ammonia, the use of ammonia in the context of various fuel solutions (combustion engines and fuel cell engines), and the discussion of ammonia-powered vehicles in the context of air pollution. The paper offers new insights into identifying the challenges and obstacles that may arise in the case of the massive use of green ammonia as a fuel for land transport. In addition, the review presents the latest information on the technological readiness of the necessary infrastructure for the production, transport, storage, and utilization of green ammonia in internal combustion or electric engines.
... An ammonia-fuelled engine produces NO X during the combustion, whereas an SOFC system fuelled by ammonia avoids most NO X formation by producing N 2 as the main nitrogen-containing product [112]. Several investigations concluded that an SOFC running directly on ammonia shows similar [114][115][116] or even higher [30,117,118] efficiency than hydrogen. Frandsen et al. [119] demonstrated with a multiphysics 3D stack model and cell experiments that internal cracking is very fast at typical operating conditions, anode recirculation appears feasible, and only negligible reforming in heat exchangers will occur. ...
The marine industry must reduce emissions to comply with recent and future regulations. Solid oxide fuel cells (SOFCs) are seen as a promising option for efficient power generation on ships with reduced emissions. However, it is unclear how the devices can be integrated and how this affects the operation of the ship economically and environmentally. This paper reviews studies that consider SOFC for marine applications. First, this article discusses noteworthy developments in SOFC systems, including power plant options and fuel possibilities. Next, it presents the design drivers for a marine power plant and explores how an SOFC system performs. Hereafter, the possibilities for integrating the SOFC system with the ship are examined, also considering economic and environmental impact. The review shows unexplored potential to successfully integrate SOFC with thermal and electrical systems in marine vessels. Additionally, it is identified that there are still possibilities to improve marine SOFC systems, for which a holistic approach is needed for design at cell, stack, module, and system level. Nevertheless, it is expected that hybridisation is needed for a technically and economically feasible ship. Despite its high cost, SOFC systems could significantly reduce GHG, NOX, SOX, PM, and noise emissions in shipping.
... Barelli et al. [31] conducted an experimental test and designed a system for operating an SOFC-based power system using ammonia as a fuel. The study demonstrates the feasibility and potential of using ammonia as a fuel for SOFCs, which could have implications for the development of sustainable energy systems. ...
Ammonia is being considered as a promising alternative to hydrogen fuel in solid oxide fuel cells (SOFCs) due to its stability and ease of storage and transportation. This study investigates the feasibility of using ammonia fuel in a tubular SOFC for shipborne unmanned aerial vehicles (UAVs). The paper develops a 3D model of a tubular-anode-supported SOFC single cell and conducts numerical simulations to analyze the impact of different operating conditions on SOFC performance. The study optimizes the SOFC’s performance by adjusting its working parameters and overall structure, revealing that increasing temperature and porosity enhance performance, but excessively high values can cause deterioration and instability in the cell. The study also finds that the cathode-supported (CS)-SOFC outperforms the anode-supported (AS)-SOFC, mainly due to its thicker cathode layer, providing better sealing and oxygen supply, resulting in a more uniform current density distribution. The paper provides valuable insights into the potential use of ammonia fuel for shipborne UAVs and offers a foundation for future research and development in the field of SOFCs. The results indicate that increasing the temperature and porosity of the SOFC can enhance battery performance, but excessive values can cause deterioration and instability in the cell. The study also highlights the impact of different operating conditions on SOFC performance, with a significant performance improvement observed in the range of 0.6–0.8 V. Additionally, the CS-SOFC outperforms the AS-SOFC due to its thicker cathode layer, but both have significant potential for development.
