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This paper proposes a novel combined cooling, heating, and power (CCHP) system integrated with molten carbonate fuel cell (MCFC), integrated solar gas-steam combined cycle (ISCC), and double-effect absorption lithium bromide refrigeration (DEALBR) system. According to the principle of energy cascade utilization, part of the high-temperature waste gas discharged by MCFC is led to the heat recovery steam generator (HRSG) for further waste heat utilization, and the other part of the high-temperature waste gas is led to the MCFC cathode to produce CO 3 2−, and solar energy is used to replace part of the heating load of a high-pressure economizer in HRSG. Aspen Plus software is used for modeling, and the effects of key factors on the system performances are analyzed and evaluated by using the exergy analysis method. The results show that the new CCHP system can produce 494.1 MW of electric power, 7557.09 kW of cooling load and 57,956.25 kW of heating load. Both the exergy efficiency and the energy efficiency of the new system are 61.69% and 61.64%, respectively. Comparing the research results of new system with similar systems, it is found that the new CCHP system has better ability to do work, lower CO 2 emission, and can meet the cooling load, heating load and electric power requirements of the user side at the same time. • A novel CCHP system coupling MCFC and ISCC system is proposed in this paper. • The effects of key factors on the system performances are analyzed and evaluated. • Performance variation rules of the new system with the change of DNI are revealed. • The new system performances are obviously improved compared with similar systems. [ABSTRACT FROM AUTHOR]

Hydrogen is rapidly turning into one of the essential energy carriers for future sustainable energy systems. The main reason for this is the possibility of off-peak excess power production and storage of renewable stations such as wind farms, photovoltaic plants, etc. For hydrogen (itself) or its sub-productions methanol, ammonia, etc. Such energy systems are so-called power2X technologies. For hydrogen and other biogases, using a fuel cell is a promising method for returning the fuel to the power grid or electric cars in the form of electricity. In this paper, a novel hybrid energy system consisting of a molten carbonate fuel cell (MCFC) and different options to generate hydrogen from the waste heat of the MCFC is investigated. The system consists of two scenarios of weather using proton exchange membrane electrolyzer (PEME) of vanadium chloride (VCL) cycle. The article presents a comprehensive thermodynamic, economic, and environmental analysis of the system optimized by tri-objective optimization (as an innovative optimization) methods. The aim of the optimization task here is to minimize the costs and emissions while maximizing efficiency. A parametric study is conducted to see the effect of different design parameters on the system's performance. Results demonstrate that fuel utilization factor, stack temperature, and current density have the most critical effect on the system performance. In addition, the system coupled with the VCL cycle exhibits better performance than the system with PEME. In addition, at the optimized point, the efficiency, cost rate, and emission become 69.28%, 3.73 ($/GJ), and 1.16 kg/kWh, respectively. In addition, the produced hydrogen in VCL and PEME are 585 kg/day and 293 kg/day respectively. • The hybrid system based on gasifier and MCFC is modeled from 4E perspectives. • The cutting-edge tri-objective optimization is considered to minimize cost and emission and maximize the efficiency. • Two novel methods of producing hydrogen from waste heat is presented and analyzed in detail. • In optimum conditions, the exegetic efficiency and unit product cost become 69.28% and 3.73 ($/GJ) respectively. [ABSTRACT FROM AUTHOR]

Due to a high conductivity of about 0.1 S·cm−1, Li-Na-K carbonate eutectic and Sm-doped ceria composite material is a good electrolyte candidate for hybrid fuel cells operating between 500 °C and 600 °C. The present paper aims at a deeper understanding of the species and mechanisms involved in the ionic transport through impedance spectroscopy and thermal analyses, in oxidizing and reducing atmospheres, wet and dry, and during two heating/cooling cycles. Complementary structural analyses of post-mortem phases allowed us to evidence the irreversible partial transformation of molten carbonates into hydrogenated species, when water and/or hydrogen are added in the surrounding atmospheres. Furthermore, this modification was avoided by adding CO2 in anodic and/or cathodic compartments. Finally, a mechanistic model of such composite electrical behavior is suggested, according to the surrounding atmospheres used. It leads to the conclusions that cells based on this kind of electrolyte would preferably operate in molten carbonate fuel cell conditions, than in solid oxide fuel cell conditions, and confirms the name of "Hybrid Fuel Cells" instead of Intermediate Temperature (or even Low Temperature) Solid Oxide Fuel Cells. [ABSTRACT FROM AUTHOR]

The world power sector is going to change over from its conventional large scale power systems to novel small scale efficient ones, where the fuel cell technology is a promising option. In this paper, a novel tri-generation system based on MCFC is presented for power, hydrogen and freshwater production. The Solid Oxide Electrolyzer Cell (SOEC) is employed for hydrogen production and Multiple Effect Distillation (MED) system is used for freshwater generation to recover the MCFC waste heat. Comprehensive exergoeconomic evaluation and tri-objective optimization is conducted considering exergy efficiency, product cost and CO 2 emission as the objectives. Besides the operating conditions and optimal design variables are determined for single-objective optimizations. The results show that, tri-generation system yields at least 4.5 % gain in exergetic efficiency compared to the standalone MCFC. From the parametric study it is revealed that, higher values of hydrogen production is reached for lower fuel utilization factor and stack temperature and higher current densities. Meanwhile, higher values of freshwater is attained with higher steam to carbon ratio, fuel utilization factor, stack temperature, and lower current density values. The tri-objective optimization results demonstrated that the minimum cost and emissions can be reached to 9.37 $/GJ, and 1.425 ton/MWh, respectively while the maximum efficiency is 46.54% at the best point. [Display omitted] • A novel MCFC-based tri-generation system for power, hydrogen and freshwater is proposed. • Exergy, exergoeconomic and environmental analyses are performed on the proposed system. • Tri-objective optimization is conducted to determine the best operating conditions. • Unit product cost of 9.37 $/GJ is obtained under tri-objective optimal operating conditions. • Higher stack temperature brings about higher hydrogen and freshwater production. [ABSTRACT FROM AUTHOR]

In the present paper, a novel combined cooling, heating and power cycle is studied. In the cycle, three technologies of molten carbonate fuel cell, Stirling engine (Alpha type) and Kalina power generation cycle are combined. The Stirling engine and Kalina cycle are used to recover heat from the stack gases of the molten carbonate fuel cell. Also, the condenser of the Kalina cycle is used to supply heating, while the cooling load is produced by an absorption chiller. In analyzing this cycle, a parametric study and a sensitivity analysis are presented to investigate the cycle from thermodynamic and environmental points of views. The analyses are carried out by selecting 7 design parameters, which four-most important parameters include current density, air to fuel ratio at the fuel cell input, fuel cell input pressure and the temperature ratio at the Stirling engine. The results showed that the combined cycle saves up to 45% fuel in comparison to the conventional systems. The overall and electrical efficiencies of the cycle can reach more than 70% and 50%, respectively. Furthermore, carbon monoxide and carbon dioxide yearly reduction for 6000 h of operation is 15 tons and 225 tons, respectively. • Designing a novel Eco-friendly combined cooling heating and power cycle. • Saving fuel by up to 45% in comparison with the conventional systems. • Attaining overall and electrical efficiencies of more than 70% and 50%. • Reduction in CO and CO 2 by up to 15 tons and 225 tons in 6000 h of operation. [ABSTRACT FROM AUTHOR]

In this paper a coal-fired power plant with CO 2 capture by integrating MCFC (molten carbonate fuel cell) system is studied. Aspen Plus software is used to establish the overall system model. The thermal and economic performances of the new hybrid system are investigated and compared with the benchmark system of coal-fired power plant without CO 2 capture and the benchmark system with CO 2 capture by using the MEA (Mono ethanol amine) method. The effects of the key parameters on the thermal and economic performances of the new hybrid system are studied. The research results show that compared with the benchmark system without CO 2 capture, the efficiency of the new hybrid system is increased and the maximum CO 2 capture rate can be 96.21%. While ensuring the high CO 2 capture rate, the total efficiency of the new system with CO 2 capture can be improved by4.05 percent points. Compared with the conventional CO 2 capture method with the MEA, the CO 2 capture method based on the electrochemical method of MCFC proposed in this paper has the obvious thermal performance advantage, however, its economic performance should be further improved. Achievements in this paper will provide the valuable reference for CO 2 capture of coal-fired power plant with low energy consumption. [ABSTRACT FROM AUTHOR]

Abstract In this paper, a novel molten carbonate fuel cell hybrid power generation process with using solar parabolic dish thermal energy is proposed. The process contains MCFC, Oxy-fuel and Rankine power generation cycles. The Rankine power generation cycles utilized various types of working fluid to emphasize taking advantage of the cycles in different thermodynamic conditions. The required hot and cold energies are provided from solar dish parabolic thermal hot and liquefied natural gas (LNG) cold energies, respectively. The carbon dioxide (CO 2) from MCFC effluent stream is captured from the process at liquid state. The process total heat integrated and in this regards, no need to any hot and cold external sources with the net electrical power generation. The energy and exergy analysis are conducted to determine the approaches to improve the process performance. This integrated structure consumed 2.30 × 106 kg h−1 of air and 2.67 × 106 kg h−1 of LNG to generate 292597 kW of net power. The products of this integrated structure are 6.25 × 104 kg h−1 of condensates, 183 kg h−1 of water vapor, 2.20 × 106 kg h−1 of MCFC effluent stream, 2.60 × 106 kg h−1 of natural gas and 1.10 × 105 kg h−1 of CO 2 in liquid state. The presented new integrated structure has overall thermal efficiency of 73.14% and total exergy efficiency of 63.19%. Also, sensitivity analysis is performed for determination of the process key parameters which affected the process operating performance. Highlights • A hybrid power generation, carbon dioxide capturing and liquefaction process is developed. • The system includes molten carbonate fuel cell, solar parabolic dish, Oxy-fuel and Rankine power generation cycles. • The overall exergy efficiency of the system is obtained 63.19%. • Sensitivity analysis of the integrated system is conducted. [ABSTRACT FROM AUTHOR]

The integrated system of a solid oxide fuel cell and molten carbonate fuel cell theoretically has very good potential for power generation with carbon dioxide utilization. However, the control strategy of such a system needs to be considered for efficient operation. In this paper, a control structure design for an integrated fuel cell system is performed based on economic optimization to select manipulated variables, controlled variables and control configurations. The objective (cost) function includes a carbon tax to get an optimal trade-off between power generation and carbon dioxide emission, and constraints include safe operation. This study focuses on the top-down economic analysis which is the first part of the design procedure. Three actively constrained regions as a function of the main disturbances, namely, the fuel and steam feed rates, are identified; each region represents different sets of active constraints. Under nominal operating conditions, the system operates in region I. However, operating the fuel cell system in region I and II can use the same structure, but in region III, a different control structure is required. [ABSTRACT FROM AUTHOR]

Molten Carbonate Fuel Cell (MCFC) has been emerging as a promising renewable power system. It is still challenging to operate the MCFC to meet its varying demands because of its nonlinearity and complex dynamics. This paper proposes a novel MCFC operation framework based on PID auto-tuning control. A case study is presented to illustrate the applicability of the strategy with some comments. [ABSTRACT FROM AUTHOR]

This paper studies a gas-steam combined cycle system with CO2 capture by integrating the MCFC (molten carbonate fuel cell). With the Aspen plus software, this paper builds the model of the overall MCFC-GT hybrid system with CO2 capture and analyzes the effects of the key parameters on the performances of the overall system. The result shows that compared with the gas-steam combined cycle system without CO2 capture, the efficiency of the new system with CO2 capture does not decrease obviously and keeps the same efficiency with the original gas steam combined cycle system when the carbon capture percentage is 45%. When the carbon capture percentage reaches up to 85%, the efficiency of the new system is about 54.96%, only 0.67 percent points lower than that of the original gas-steam combined cycle system. The results show that the new system has an obvious superiority of thermal performance. However, its technical economic performance needs be improved with the technical development of MCFC and ITM (oxygen ion transfer membrane). Achievements from this paper will provide the useful reference for CO2 capture with lower energy consumption from the traditional power generation system. [ABSTRACT FROM AUTHOR]

Abstract: One of the most promising technologies for stationary power applications is the Molten Carbonate Fuel Cell (MCFC). This is due to its high efficiency, low emissions and the medium–high operating temperature. This high temperature allows for hybridization with other power generation technologies where the bottoming cycle recovers part of the heat in the fuel cell exhaust stream, hence resulting in highly efficient hybrid systems. The current MCFC hybrid system designs use microturbines as bottoming cycle. This paper presents the integration of a MCFC with a bottoming Humid Air Turbine (HAT) instead of the conventional microturbine. The HAT cycle, even if still under development, provides a relatively simple and inexpensive solution to increase the power output of the microturbine. An indirect integration between the MCFC and the HAT cycle is chosen aiming to simplify the layout and operation of the new system and considering that the necessary modifications to be performed in the microturbine are relatively simple (and therefore the additional equipment is expected to be relatively economical). The results presented in this paper show the potential of this MCFC–HAT combination with an increase of the net power output of 6 percentage points and an efficiency increase of 3 percentage points from the high efficiency conventional hybrid system (MCFC–MGT). An economic analysis as function of the MCFC investment cost is presented showing a break-even-cost of 2092 €/kW improving the estimated for the MCFC–MGT. [Copyright &y& Elsevier]

The paper presents recent advances in Poland in the field of high temperature fuel cells. The achievements in the materials development, manufacturing of advanced cells, new fabrication techniques, modified electrodes and electrolytes and applications are presented. The work of the Polish teams active in the field of solid oxide fuel cells (SOFC) and molten carbonate fuel cell (MCFC) is presented and discussed. The review is oriented towards presenting key achievements in the technology at the scale from microstructure up to a complete power system based on electrochemical fuel oxidation. National efforts are covering wide range of aspects both in the fundamental research and the applied research. The review present the areas of (i) novel materials for SOFC including ZrO 2 -based electrolytes, CeO 2 -based electrolytes, Bi 2 O 3 based electrolytes and proton conducting electrolytes, (ii) cathode materials including thermal shock resistant composite cathode material and silver-containing composites, (iii) anode materials, (iv) metallic interconnects for SOFC, (v) novel fabrication techniques, (vi) pilot scale SOFC, including electrolyte supported SOFC (ES-SOFC) and anode supported SOFC (AS-SOFC), (vii) metallic supported SOFC (MS-SOFC), (viii) direct carbon SOFC (DC-SOFC), (ix) selected application of SOFC, (x) advances in MCFC and their applications, (xi) advances in numerical methods for simulation and optimization of electrochemical systems. [ABSTRACT FROM AUTHOR]

Biomass, integral to life, is one of the main energy sources that modern technologies could widely develop, overcoming inefficient and pollutant uses. The sugarcane bagasse is one of the more abundant biomass. Moreover, the fluctuating sugar and energy prices force the sugarcane companies to implement improved power plants. Thanks to a multiyear collaboration between University of Rome and University of Piura and Chiclayo, this paper investigates, starting from the real data of an old sugarcane plant, the energy efficiency of the plant. Furthermore, it explores possible improvements as higher temperature and pressure Rankine cycles and innovative configurations based on gasifier plus hot gas conditioning and gas turbine or molten carbonate fuel cells. Even if the process of sugar extraction from sugarcane and the relative Rankine cycles power plants are well documented in literature, this paper shows that innovative power plant configurations can increase the bagasse-based cogeneration potential. Sugarcane companies can become electricity producers, having convenience in the use of sugarcane leaves and trash (when it is feasible). The worldwide implementation of advanced power plants, answering to a market competition, will improve significantly the renewable electricity produced, reducing CO2 emissions, and increasing economic and social benefits. [Copyright &y& Elsevier]

High temperature fuel cell technologies, solid oxide fuel cells (SOFCs) and molten carbonate fuel cells (MCFCs), are considered for their potential application to carbon dioxide emission control. Both technologies feature electrochemical oxidisation of natural gas reformed fuels, avoiding the mixture of air and fuel flows and dilution with nitrogen and oxygen of the oxidised products; a preliminary analysis shows how the different mechanism of ion transport attributes each technology a specific advantage for the application to CO2 separation. The paper then compares in the first part the most promising cycle configurations based on high efficiency integrated SOFC/gas turbine “hybrid” cycles, where CO2 is separated with absorption systems or with the eventual adoption of a second SOFC module acting as an “afterburner”. The second part of the paper discusses how a MCFC plant could be “retrofitted” to a conventional fossil-fuel power station, giving the possibility of draining the majority of CO2 from the stack exhaust while keeping the overall cycle electrical efficiency approximately unchanged. [Copyright &y& Elsevier]

• A novel integrated gas turbine, MCFC and ORC system with CO 2 recovery is proposed. • The exergy utilization diagram (EUD) methodology is applied to reveal the energy conversion process more clearly. • The temperature matching of the new system is optimized in this paper. • When the CO 2 capture rate is 0.85, the thermal efficiency of the new system is 62.34% and the exergy efficiency is 60.08%. A huge amount of energy is consumed by recovering CO 2 in the gas turbine (GT) exhaust gas with the traditional method because of the low CO 2 concentration. A new system integrated with gas turbine, MCFC and ORC with CO 2 capture is proposed in this article. CO 2 in the gas turbine exhaust gas is concentrated by the MCFC electrochemical reaction. Compared with traditional CO 2 capture methods, it effectively decreases the energy consumption of CO 2 capture. The mid-temperature exhaust gas heat is recovered by two stages organic Rankine cycle systems. The influences of the major parameters on the new system performance are deeply studied. Also, the thermal and economic performances of the new system are compared with those of the reference system without CO 2 capture and with CO 2 capture based on the traditional mono-ethanol ammine (MEA) method. The results show that, when the CO 2 capture rate is 0.85, the thermal efficiency of the new system is 62.34%, 3 percentage points higher than that of the gas steam combined cycle system without CO 2 capture; and the exergy efficiency is 60.08%, 2.47 percentage points higher than that of the gas steam combined cycle system without CO 2 capture. Its economic performance will be improved with the reduction of the MCFC cost in the future. [ABSTRACT FROM AUTHOR]

Fuel cell and electrolysis depend critically on catalysis. Haldor Topsøe has been a leader in this field and initiated many innovations. The paper reviews the types of fuel cells, electrolyzers, and the thermodynamic aspects involved, and then discusses the technology from the viewpoint of available feedstocks. Important phenomena that determine the stability of the devices, such as carbon deposition and sulfur poisoning, are reviewed as well. Although fuel cells are still awaiting their commercial breakthrough, high-temperature electrolysis in combination with the catalytic synthesis undoubtedly has potential in sustainable energy scenarios. [ABSTRACT FROM AUTHOR]

In this paper, a new Integrated Gasification Combined Cycle (IGCC) system with less CO 2 emission by integrating a Molten Carbonate Fuel Cell (MCFC) to capture CO 2 has been proposed. The performance of the new system is compared with other three systems: a conventional IGCC system without CO 2 capture, an IGCC system with pre-combustion capture and an IGCC system with oxy-fuel combustion capture. In addition, the effects of the key parameters of MCFC such as CO 2 utilization factor, fuel utilization factor and the operating temperature of MCFC on the new system performance have been analyzed and compared. The results show that when the CO 2 capture rate is 88%, the efficiency of the new system is about 47.31%, 2.97% higher than that of the IGCC without CO 2 capture, 10.45% higher than the IGCC system with pre-combustion CO 2 capture, and 12.55% higher than the IGCC system with oxy-fuel combustion CO 2 capture. Though the new system has an obvious superiority of thermal performance, its technical economic performance needs be improved with the technical development of MCFC. The research achievements will provide a new way for further study on CO 2 capture from IGCC system with lower energy penalty. [ABSTRACT FROM AUTHOR]

In this paper the results of an on-site experimental analysis carried out on a Molten Carbonate Fuel Cell (MCFC) fed by different fuels (hydrogen, landfill gas and different mixtures of them) are presented. The examined MCFC is one of the experimental devices of an innovative power plant located at the urban landfill of Giugliano in Campania (Naples, Italy). Here, electricity is produced through four cogenerative reciprocating engines and one cogenerative gas turbine fed by landfill gas, operating since 2003. At the same site, two different fuel cells are installed for scientific purposes. During the considered experimental campaign, the MCFC is initially supplied by hydrogen for testing the system at the best operating conditions. Afterward, the fuel cell is fed by mixtures of different ratios of hydrogen and reformed landfill gas. For this reason, the system is equipped with an external reformer and a suitable gas cleaning. In order to analyse the system energy performance under varying electricity loads (obtained through an electronic device), several tests were carried out. In addition, several stress tests were also performed aiming at analysing the system endurance when fed by landfill gas. The experimental results concerning the produced electric currents and voltages show satisfactory performance of the system, while the obtained operating temperatures and cell reliability still need to be improved. [ABSTRACT FROM AUTHOR]

Various supercritical carbon dioxide (S–CO 2 ) cycles for a power conversion system of a Molten Carbonate Fuel Cell (MCFC) hybrid system are studied in this paper. Re-Compressing Brayton (RCB) cycle, Simple Recuperated Brayton (SRB) cycle and Simple Recuperated Transcritical (SRT) cycle layouts were selected as candidates for this study. In addition, a novel concept of S–CO 2 cycle which combines Brayton cycle and Rankine cycle is proposed and intensively studied with other S–CO 2 layouts. A parametric study is performed to optimize the total system to be compact and to achieve wider operating range. Performances of each S–CO 2 cycle are compared in terms of the thermal efficiency, net electricity of the MCFC hybrid system and approximate total volumes of each S–CO 2 cycle. As a result, performance and total physical size of S–CO 2 cycle can be better understood for MCFC S–CO 2 hybrid system and especially, newly suggested S–CO 2 cycle shows some success. [ABSTRACT FROM AUTHOR]

In this paper a generalized model, based on system-level approach, for predicting the High Temperature Fuel Cells (HTFCs) behavior and performance is presented. The system-level model allows to forecast the HTFC performance under different operating conditions (cell temperature, anode off-gas recirculation, reactants temperatures, fuel and oxidant utilization factors, etc.) and cell design (tubular and planar configurations and with co-flow, counter-flow and cross-flow arrangements). Mass and energy balances are solved by considering both the electrochemical (i.e. electro-oxidation of hydrogen) and thermochemical reactions (i.e. reforming and shifting reactions) which occur in the anode and cathode sides and by applying different equations systems to take into account the type of fuel cell (MCFC or SOFC). The ability of the proposed model in the HTFCs performance prediction is pointed out by the model validation carried out by using experimental data and by analyzing the impact of the model calibration parameters on the cell voltage calculation carried out by means of a sensitivity analysis. Numerical results show that the model allows to characterize the behavior of the HTFCs with a good approximation so, thanks to the simplicity of the simulation procedure and to the small computational time efforts, it can be a useful tool for predicting the performance of hybrid power plants or more complex systems in which the fuel cell is one of the main components. [ABSTRACT FROM AUTHOR]

In order to increase the lifetime and performance of the molten carbonate fuel cell, it is compulsory to control the corrosion and dissolution of the state of the art porous nickel oxide cathode. A protective coating constituted by more stable oxides appears to be the best approach. Previous research on CeO 2 coatings obtained by DC reactive magnetron sputtering to protect the Molten carbonate fuel cell cathode gave promising results but it was necessary to improve the coating adhesion. In this paper Atomic Layer Deposition, producing high quality, homogeneous and conformal layers, was used to obtain thin layers of CeO 2 (20 nm and 120 nm) deposited over porous nickel. CeO 2 -Ni coated samples were tested as cathodes in Li 2 CO 3 -K 2 CO 3 (62-38 mol %) eutectic mixture under standard cathode atmosphere (CO 2 /air 30:70 vol. %). Structural and morphological characterizations of the nickel coated cathode before and after electrochemical tests in the molten carbonate melt are reported together with the Open Circuit Potential evolution all over 230 h for both the bare porous nickel and the CeO 2 -coated samples. [ABSTRACT FROM AUTHOR]

In the world of alternative energy sources, the Molten Carbonate Fuel Cell (MCFC) is one of the promising technologies for the efficient conversion of hydrogen or hydrocarbons to power and heat. One of the main issues for optimizing this device is the control of the dissolution of the state-of-the-art porous nickel oxide cathode. A protective coating by more stable metal oxides seems to be one of the best solutions. In this paper, ultra-thin layers of TiO2 (50 nm), Co3O4 (50 nm) and CeO2 (20 nm) were deposited on porous nickel substrates, by a sequential CVD technique, known as Atomic Layer Deposition (ALD), producing high quality, homogeneous and conformal layers. The electrochemical behavior and morphological features of the three coated samples were compared in a Li2CO3-K2CO3 (62-38 mol%) eutectic melt under a standard cathode atmosphere (CO2/air 30:70 vol%) for 230 h. Finally, the respective advantages and drawbacks of Co3O4, TiO2 and CeO2 coatings are pointed out. [ABSTRACT FROM AUTHOR]

Abstract: In this paper a novel integrated plant, designed for the co-production of electricity and synthetic natural gas (SNG), has been proposed as suitable strategy for renewable energy storage and CO2 emission control. The hydrogen generation by electrolysis and its use for SNG production is the approach chosen for the energy storage (chemical storage), while the CO2 control is performed by using (or recycling) the CO2, concentrated in the anode exhausts of a molten carbonate fuel cell, in the chemical processes of the plant (coal hydrogasification and SNG production processes). The proposed HyCRESt plant, acronym of Hydrogasification of Coal for Renewable Energy Storage, consists of three main sections: i) the hydrogasification island, in which the coal is gasified in hydrogen environment to a methane rich fuel gas stream (syngas); ii) the power island, in which the syngas is used as fuel for the electric power generation by using a molten carbonate fuel cell (MCFC) power unit; iii) the SNG island, in which the syngas is converted into a synthetic natural gas stream. The plant performance, in terms of co-production efficiency, CO2 avoided and fuel saving, has been evaluated by means of thermochemical and electrochemical models able to predict energy and mass balances. Results have pointed out that the co-production of electric and chemical powers allows to achieve system efficiencies greater than 55% with fuel saving values higher than 6% and CO2 avoided ranging from 20% (only electric power generation) to 120% (only SNG generation). [Copyright &y& Elsevier]

Abstract: One of the main issues for optimizing the molten carbonate fuel cell (MCFC) is the control of the corrosion and dissolution of the state-of-the-art porous nickel oxide cathode. A protective coating constituted by more stable oxides seems to be the best solution. In this paper, very thin layers of TiO2 (50 and 300 nm) are processed by a sequential CVD technique, Atomic Layer Deposition (ALD), which produces high quality, homogeneous and conformal layers. Structural, morphological and electrochemical behaviors of TiO2-coated samples are tested in a Li2CO3–K2CO3 (62:38 mol%) eutectic melt under a standard cathode atmosphere: CO2/air (70:30 bar%). Ni solubility is determined by ICP-AES. The protective role of TiO2 layers and the consequent decrease in Ni solubility have been clearly evidenced. [Copyright &y& Elsevier]

Molten Carbonate Fuel Cells (MCFC) offer several advantages that are accelerating the research and development effort. Recent advances include improved materials, new fabrication techniques and new designs, flow configurations and applications. Nevertheless, several factors are holding back large scale implementation of fuel cells, especially in distributed energy generation, a major one being their long response time to changing parameters. Whereas alternative mathematical models of the molten carbonate fuel cell stack have been developed over the last decade, there are no reported analyses of regarding the application of models for emergency scenarios such as fuel cell malfunctions. This paper presents the 0D model of MCFC, calibrated to the appropriate available experimental data. This study investigates a generic molten fuel cell stack with nominal power output of 1 kWel. As daily, weekly and monthly variations in the electrical power load are expected, there is a need to develop numerical tools to predict the unit's performance with high accuracy. Hence, a fully physical dynamic model of an MCFC stack was developed and implemented in Aspen HYSYS 10 modeling software to enable predictive analysis of the dynamic response. The model is used to simulate a number of few malfunctions with 5. 66% broken cells in the stack. Losses of performance are obtained, manifested by rising operating temperature and falling power output. Moreover, a number of emergency operation scenarios were investigated, such as sudden loss of electric load, fuel and oxidiant supply. The presented model exhibits high accuracy and accounts for thermal and electrochemical processes and parameters. The paper presents the methodology used in the study to analyze the sensitivity of key scenarios such as load changes and emergencies. Further functionality of the model, which was validated using real operating data, is discussed. • Dynamic model of a Molten Carbonate Fuel Cell 1 kW stackis proposed. • The model was calibrated to the appropriate available experimental data. • The load changes and emergency situations were examined. [ABSTRACT FROM AUTHOR]

The paper presents a mathematical model of a molten carbonate fuel cell with a catalyst in the anode channel. The modeled system is fueled by methane. The system includes a model of the steam reforming process occurring in the anode channel of the MCFC fuel cell and the model of the cell itself. A reduced order model was used to describe the operation of the molten carbonate fuel cell, whereas a kinetic model describes the methane steam reforming. The calculations of the reforming were done in Aspen HYSYS software. Four values of the steam-to-carbon ratio (2.0, 2.5, 3.0, and 3.5) were used to analyze the performance of the reforming process. In the first phase, the reaction kinetics model was based on data from the literature. [ABSTRACT FROM AUTHOR]

Abstract: A good portion of greenhouse gas emissions is caused by the energy used in the built environment. Emission reduction goals may be achieved by combining cogeneration with fuel cells (FC). This paper investigates electricity production costs for FC based cogeneration systems with recent data for Swedish conditions. The types of FCs that are investigated are proton exchange membrane FC and molten carbonate FC. Based solely on cost, FC based cogeneration systems cannot compete with conventional systems. However, our results show that Molten Carbonate FC based cogeneration systems will be profitable by 2020. To compete with conventional systems, the capital cost, lifetime and efficiency of FCs must be improved. Creation of a reasonably broad market is essential since it will greatly help to reduce capital costs and operation and maintenance (O&M) costs, the dominating parts of the overall costs according to the analysis. [Copyright &y& Elsevier]

Abstract: This work presents a comparative analysis of hybrid systems based on molten carbonate fuel cells and making use of closed-cycle externally-heated bottoming systems. Two options are considered: reciprocating (Stirling) engines and supercritical carbon dioxide turbines. These two engines share the common feature of working on closed cycles with pure fluids (H2 and CO2 respectively) but, at the same time, they differ in their internal structure: Stirling engines make use of volumetric machinery whereas the supercritical carbon dioxide gas turbine (SCO2) is composed by turbomachinery. In both cases, the working fluid is subjected to very high pressures and temperatures in the range of 50–200 bar and 40–650 °C. A brief description of both bottoming systems is provided in the first sections of this article along with their expected performance in on-design and off-design (part-load) operation. The analysis of each system is therefore split into three stages. First, the most relevant features of the models of performance are discussed. Then, a comparison is shown for on-design operation aiming to evaluate the maximum efficiency attainable by the proposed engines. Finally, an analysis of off-design operation is presented. The final section of paper concludes that hybrid systems based on atmospheric fuel cells and externally heated closed-cycle bottoming engines have the potential to outperform conventional pressurised fuel cell plus gas turbine hybrids while avoiding the demanding operating conditions on the fuel cell topping system of the latter configuration. [Copyright &y& Elsevier]

Abstract: In spite of its slow commercial deployment, fuel cells are amongst the most efficient and environmentally friendly electric power generators. The case of Molten Carbonate Fuel Cells is even more interesting since, in addition to these features that are common to all fuel cells, these systems can be used as active carbon capture devices due to their capability to migrate carbon dioxide from one electrode (cathode) to another (anode). In this context, this work presents the operation of a fuel cell of this type coupled to a combined heat and power plant based on gas reciprocating engines as typically used in wastewater treatment plants. The biogas produced in the water sludge digestion process is burnt in the reciprocating engines, whose exhaust gases are mixed with air and blown into the fuel cell cathode. The carbon dioxide contained in this stream is conveyed in the form of carbonate ions (CO3 =) through the electrolyte to the anode where it reacts with the hydrogen fuel, being released as carbon dioxide. The exhaust gases from the anode comprise carbon dioxide, water steam and a small fraction of unspent hydrogen fuel. The combustion of the latter species with pure oxygen followed by a cooling process permits separating a gaseous stream of pure carbon dioxide from a liquid stream of water. The interest of this carbon sequestration system is twofold. On one hand this system captures CO2 and, at the same time, generates electricity as opposed to conventional systems based on amines or other sorbents which exhibit high power consumption. On the other hand, the avoided CO2 can be traded in a potential carbon trading system. Nevertheless, in spite of the undisputable thermodynamic and environmental benefits, the very high capital cost of the fuel cell might bring about a lack of economic interest in comparison with the standard reference plant using gas engines only. Thus, this paper reviews different configuration based on fuel cells and provides an interesting economic assessment with respect to these novel proposals. More in particular, it is shown that using fuel cells is not economically attractive presently given the low commercial maturity of these devices though, in a near future where higher technology readiness levels are expected, a definite advantage over conventional facilities is envisaged. [Copyright &y& Elsevier]

Abstract: This paper introduces the special issue of this Journal dedicated to the “International Workshop on Molten Carbonates and Related Topics”, IWMC2011. Molten carbonates are mostly known as electrolytes in molten carbonate fuel cells (MCFCs). Many advances have been reached in the last decade on the development of such electrochemical generators. MCFCs can be considered as a mature technology close to the real market. However, new materials and approaches are necessary to increase their performance and lower their costs. Lately, molten carbonates are also used for CO2 capture with ambitious industrial projects and a growing interest in many countries, in particular in Europe. Furthermore, molten carbonates are also seriously considered in direct carbon fuel cells (DCFCs), directly as electrolytes or as media to feed solid oxide fuel cells with solid carbon fuel. Noteworthy is the astonishing research activity on composite fuel cells combining molten carbonates with solid oxide fuel cells. All these promising topics and others are briefly described emphasising their novelty. [Copyright &y& Elsevier]

Abstract: Nickel cathode is transformed to lithiated nickel oxide by oxidation and lithiation during the conditioning process for molten carbonate fuel cells. In the lithiation process, the amount of lithium inserted into nickel oxide depends on the oxygen and CO2 composition and this affects the performance of nickel cathode. In this paper, CO2 interruption technique was applied to investigate the effects of CO2 interruption on the lithiation of nickel oxide. During the CO2 interruption for 24 h in cathode operating at 20 mA/cm2, the carbonate ion in electrolyte was decomposed into oxygen and CO2. With the additional oxygen on cathode surface, Ni2+ is oxidized to Ni3+ with formation of cation vacancy in NiO. The lithium content of cathode increased from 3.0 at.% to 17.4 at.% (over-lithiation) and hence LiNiO2 phase was formed in the cathode. Cathode surface area is increased by a decrease in NiO particle size with the formation of micropores. The morphological change in cathode enhanced its electrochemical performance in the single cell. Cell voltage of the single cell that has been subjected to CO2 interruption at 120 mA/cm2 was enhanced by 300 mV, due primarily to the reduction in the internal resistance from 2.0 to 0.8 Ω cm2 and also in the charge transfer resistance from 3.0 to 1.1 Ω cm2. [Copyright &y& Elsevier]

Abstract: The paper reports the main results of an investigation on biogas reforming process developed for an integration with high temperature fuel cells systems. Experimental activities have been developed to determine performances of a nickel catalyst in different biogas reforming conditions have been investigated. Attention has been addressed toward the effect of gasifier agents (CO2, H2O and O2) on outlet stream composition and carbon deposition on catalytic surface. Previously, the carbon formation rate in dry and steam reforming reactions apply to a biogas stream (CH4/CO2–60/40vol%) has been evaluated using Aspen plus chemical processor simulator in order to define the operative conditions limit and to selected the best one. A mathematical model, based on experimental data, has been developed to compare the polarization curves of a MCFC mono-cell fed with three different syngas compositions obtained by biogas reforming section in order to find out the best operational conditions for the two integrated systems (MCFC/fuel processor). A parallel trend of the the polarization curves have been obtained due to the assumptions considered for the model developing, as: (i) inlet gas composition effects on ohmic and activation loses are negligible; (ii) diffusional losses are dependent by gas compositions; (iii) diffusional losses are negligible in the graphic sections characterized by low current density. [Copyright &y& Elsevier]

Abstract: This work is divided into two main sections. First, a review of the most frequently used approaches to molten carbonate fuel cell modelling is presented. The models available in literature are found to be classified in three different groups which are carefully described in the paper. Then the models are compared and their ability to predict fuel cell performance far from the design point is tested. It is concluded that even though some models seem to be accurate close to a reference point, their estimates differ largely far from these working conditions. Accordingly, a model is selected amongst those previously reviewed and its capacity to replicate real fuel cell performance is checked against experimental data available in open literature. Such validation confirms that the model is fully satisfactory as it is able to predict fuel cell performance within less than 1.0–1.5% deviation for a wide variety of test setups. This remarkable accuracy is further reinforced by the fact that the model does not rely on experimental information (known a priori) about the system being modelled. The work also introduces an interesting approach to estimate average gas compositions to be used when evaluating Nernst potential. This approach is based on arithmetic and logarithmic means for cathode and anode respectively and it proves to yield accurate results. Overall, the work provides researchers willing to construct their own models of performance with a valuable guide to assess them in such process. [Copyright &y& Elsevier]

Abstract: This paper describes the numerical modelling of a key material-stability issue within the realm of Molten Carbonate Fuel Cells (MCFC). Differential models have been developed for the 2D and 3D distributions of current density as well as peroxide and carbon dioxide concentrations. By suitable variations of the integration domain – based on the agglomerate concept – one can describe the morphological and attending electrocatalytic evolution of porous NiO electrodes. On the basis of electrochemical data recorded during the operation of a laboratory MCFC, we have shown that this model is able to rationalise the evolution of cathode conditions leading to both improvements of electrocatalytic performance – such as lithiation – and degradation – such as agglomeration –. [Copyright &y& Elsevier]

Abstract: Carbon dioxide is more and more pointed out as one of the factors mostly responsible of climate changes. As a consequence the reduction of CO2 emissions, especially in the energy generation field, is becoming a worldwide must. This paper presents an overview on the main issues that are expected to affect, from this standpoint, power generation scenario and a spur for a critical comparison among ways to capture CO2 by proposing new aspects to be considered within the evaluation criteria. In particular attention is drawn on the fully innovative opportunities that are offered by Molten Carbonate Fuel Cells (MCFCs) as a unique option suitable to effectively combine carbon capture from thermal plants and typical benefits of hydrogen and fuel cell power generation. As an example, such a new option is compared with one of the most common technologies forecast for reducing carbon dioxide emissions and relevant results are shortly presented. [Copyright &y& Elsevier]

Abstract: A proposal for high efficiency hybrid systems based on molten carbonate fuel cells is presented in this paper. This proposal is based on adopting a closed cycle bottoming gas turbine using supercritical carbon dioxide as working fluid as opposed to open cycle hot air turbines typically used in this type of power generators. First, both bottoming cycles are compared for the same operating conditions, showing that their performances do not differ as much as initially expected, even if the initial objective of reducing compression work is accomplished satisfactorily. In view of these results, a profound review of research and industrial literature is carried out in order to determine realistic specifications for the principal components of the bottoming systems. From this analysis, it is concluded that an appropriate set of specifications must be developed for each bottoming cycle as the performances of compressor, turbine and recuperator differ significantly from one working fluid to another. Thus, when the operating conditions are updated, the performances of the resulting systems show a remarkable advantage of carbon dioxide based systems over conventional air units. Actually, the proposed hybrid system shows its capability to achieve 60% net efficiency, what represents a 10% increase with respect to the reference system. [Copyright &y& Elsevier]

Abstract: Recently, along with the growth in economic development, there has been a dramatic accompanying increase in the amount of sludge and organic waste. The disposal of such is a significant problem. Moreover, there is also an increased in the consumption of electricity along with economic growth. Although new energy development, such as fuel cells, has been promoted to solve the problem of power consumption, there has been little corresponding promotion relating to the disposal of sludge and organic waste. Generally, methane fermentation comprises the primary organic waste fuel used in gasification systems. However, the methane fermentation method takes a long time to obtain the fuel gas, and the quality of the obtained gas is unstable. On the other hand, gasification by molten salt is undesirable because the molten salt in the gasification gas corrodes the piping and turbine blades. Therefore, a gasification system is proposed by which the sludge and organic waste are gasified by molten salt. Moreover, molten carbonate fuel cells (MCFC) are needed to refill the MCFC electrolyte volatilized in the operation. Since the gasification gas is used as an MCFC fuel, MCFC electrolyte can be provided with the fuel gas. This paper elucidates the fundamental characteristics of sludge and organic waste gasification. A crucible filled with the molten salt comprising 62 Li2CO3/38 K2CO3, is installed in the reaction vessel, and can be set to an arbitrary temperature in a gas atmosphere. In this instance, the gasifying agent gas is CO2. Sludge or the rice is supplied as organic waste into the molten salt, and is gasified. The chemical composition of the gasification gas is analyzed by a CO/CO2 meter, a HC meter, and a SO x meter gas chromatography. As a result, although sludge can generate CO and H2 near the chemical equilibrium value, all of the sulfur in the sludge is not fixed in the molten salt, because the sludge floats on the surface of the carbonate by the specific gravity of sludge lighter than the carbonate, and is not completely converted into CO and H2. Moreover, the rice also shows good characteristics as a gasifying agent. Consequently, there is high expectation to using the organic waste as a molten salt gasifying agent. However, this requires lengthening the contact time between the organic waste and the molten salt. [Copyright &y& Elsevier]

Abstract: This paper presents an investigation of the gas distribution in a large-scale stack such as a 200-kW internal reforming (IR) molten-carbonate fuel cell (MCFC) stack. The gas flow scheme is important for the performance of the cell and for the temperature distribution. In order to supply gas to each cell uniformly and to achieve a reasonable temperature distribution, we have proposed a large-scale stack divided into four blocks from the point of view of the gas flow scheme. In our proposal, each block consists of 55 cells, 9 internal reforming units, and 1 internal manifold. The flow variation was examined by measurements on an element, numerical analysis, and measurements on a stack. We have found that (i) the flow variation among the four blocks is 1.5% or less and can be made better by using an orifice plate; (ii) the flow variation along the stacking direction in each block is within ±1%; (iii) improvement of the flow distribution in the reforming unit affects the uniformity of the temperature distribution in the cell area. These results can improve the prospects for 200kW stacks. [Copyright &y& Elsevier]

Abstract: The paper presents a set of two-dimensional molten carbonate fuel cell mathematical models, considering the electrical, mass and heat transfer characteristics of a molten carbonate fuel cell. A dynamic simulation model was built under the VC++ environment. The steady state and dynamic simulation results for a cross-flow molten carbonate fuel cell were obtained using the simulation model. The results are appropriate for the design and operation of molten carbonate fuel cells. [Copyright &y& Elsevier]

Abstract: This paper presents a personal view of the status and research needs of the MCFC and other molten-salt fuel cells. After an overview of current MCFC performance, compared with performance and cost of other fuel cells, improvements in power density and lifetime as well as cost reduction are identified as key priorities to accelerate the commercialization of the MCFC. In spite of its unfavorable public image (compared to, in particular, PEMFC and planar SOFC) MCFC technology has progressed steadily and cost reduction has been significant. Large-scale commercialization, especially in the distributed generation and cogeneration market, remains a possibility but its chances are highly dependent on a forceful and consistent energy policy, for example taking into account the externalities associated with various modes of electric power production from fossil fuels. In spite of steady improvements in performance, important defects in fundamental knowledge remain about wetting properties, oxygen reduction kinetics, corrosion paths and control mechanisms. These must be addressed to stimulate further simplification of design and find solutions to lifetime issues. Recently, alternative concepts of molten-salt fuel cells have been capturing attention. The direct carbon fuel cell (DCFC), reviving an old concept, has caught the attention of energy system analysts and some important advances have been made in this technology. Direct CO and CH4 oxidation have also been a focus of study. Finally, the potential of nanotechnology for high-temperature fuel cells should not be a priori excluded. [Copyright &y& Elsevier]

Abstract: Biomass gasification, integrated with molten carbonate fuel cell (MCFC) represents an alternative to the direct use of fossil fuel energy. Integration of both technologies has been under investigation for quite long time [Kivisaari T, Bjorbom P, Sylwan C. Power Sources 2002;104:115–24]. Fuel cell technology is one of the most interesting energy conversion system offering nearly zero emissions, flexibility of operation and high conversion efficiency. Another area of growing interest in energy systems is the use of biomass as a replacement for fossil fuels. In this study, atmospheric gasification technology was selected rather than pressurized gasification, used on most analysis, because the latter is considered not fully developed and a wide spread consensus has yet to be reached for medium-small application [EC project No. ENK5-CT-2002-20647 WP8.2 Report; April 2004]. A hot gas clean-up process was selected to prevent any liquid waste streams from leaving the plant and any steam from condensation in the syngas. Type and amount of impurities, chosen for the study, cover a broad range of practical interest. This paper analyzes an atmospheric gasifier system coupled with an MCFC through a specifically tailored high temperature clean-up process. Tar removal, gas clean-up and syngas compression are the major process blocks involved in such a process. The investment costs estimated are higher than previously published data due to the complexity involved. Further optimization of the steam gasifier to maximize content and to minimize tar formation is recommended to render the process more economical attractive. [Copyright &y& Elsevier]

Abstract: LiFeO2–LiCoO2–NiO ternary materials are considered as more viable alternatives to lithiated NiO, in solving the cathode dissolution problem of the Molten Carbonate Fuel Cell (MCFC). This paper presents a detailed description of fabrication and characterization of LiFeO2–LiCoO2–NiO porous gas diffusion cathodes for MCFC, together with a brief discussion on the limitations and trends observed in cathode optimization. Several LiFeO2–LiCoO2–NiO ternary compositions and a LiFeO2–NiO binary composition, were fabricated into porous cathodes by tape casting and sintering. The sintered cathodes were subjected to phase analysis, electrical conductivity and pore structural characterization. A bimodal pore structure, appropriate for the MCFC cathode, could be achieved in sintered cathodes prepared using poreformers and sub-micron size powders. The amount of poreformers significantly influences the pore structure and the electrical conductivity of sintered cathodes. Furthermore, this study indicates the nature of the compromise to be made between the electrical conductivity, phase purity, pore structure and porosity in optimization cathodes for the MCFC application. [Copyright &y& Elsevier]

Abstract: Ternary compositions of LiFeO2, LiCoO2 and NiO are expected to posses desirable characteristics for the Molten Carbonate Fuel Cell (MCFC) cathode application. This paper presents a detailed description of the synthesis of LiFeO2–LiCoO2–NiO powders as well as dense sintered materials together with a brief discussion on the common aspects and trends observed in the characterization of these materials for MCFC cathode application. Feasibility of two wet-chemical powder preparation techniques, the Pechini method and the glycine–nitrate method, was investigated to obtain powders with characteristics appropriate for cathode fabrication. Materials in the LiFeO2–NiO binary system and five ternary sub-systems, each with a constant molar ratio of LiFeO2/NiO while varying LiCoO2 content, were studied. Powders with characteristics appropriate for MCFC cathode fabrication could be obtained by the Pechini method. The particle size of LiFeO2–LiCoO2–NiO powders considerably depends on the calcination temperature and the material composition. The electrical conductivity study reveals the ability of preparing LiFeO2–LiCoO2–NiO materials with adequate electrical conductivity for MCFC cathode application. [Copyright &y& Elsevier]

Fuel cells are still a new technology, and the scientific community is in dire need for reliable data on their environmental performance. In this paper a multi-criteria life cycle assessment of a prototype molten carbonate fuel cells plant is performed; the results are subject to a systematic sensitivity analysis and compared to those for three natural gas turbine plants. Results indicate an overall good environmental performance, even when compared to modern gas turbines. Possible further improvements should focus on reducing the requirement for the employed metals (e.g. Ni, Cr), as well as increasing fuel cell life time and centralising the natural gas reforming phase. [Copyright &y& Elsevier]

Abstract: A study performed in LiCoO2-rich LiCoO2–LiFeO2–NiO ternary materials for the molten carbonate fuel cell (MCFC) cathodes is reported in this paper. LiCoO2–LiFeO2–NiO ternary materials are considered as more viable alternatives to lithiated NiO, however, the work reported so far has mainly been focused on ternary compositions rich in LiFeO2 or NiO. The present work was carried out by investigating the electrical conductivity and microstructural characteristics of the new materials first in the form of bulk pellets and then in ex situ sintered porous-gas-diffusion (PGD) cathodes. The material study reveals the ability of preparing LiCoO2–LiFeO2–NiO ternary compositions with adequate electrical conductivity by controlling the LiCoO2 content. A bimodal pore structure, appropriate for the MCFC cathode, could be achieved in sintered cathodes prepared with fine powders and pore formers. Further, the cathode fabrication study indicates the nature of the compromise to be made between the electrical conductivity, phase purity, pore structure and porosity in optimization cathodes for MCFC application. The study shows the possibility of preparing LiCoO2-rich LiCoO2–LiFeO2–NiO cathodes with promising electrical and pore structural characteristics for the MCFC. [Copyright &y& Elsevier]

The purpose of the study presented in this paper was to find out the feasibility of integrating a 50 MW fuel cell system, fed by gas from a coal gasifier, with an existing network for distribution of heat and power. The work presented is the results of the technical evaluation of a 50 MW coal fired high-temperature fuel cell power plant. The overall system can be divided into four subsystems including: coal gasification, gas cleaning, power generation and heat recovery.The final system, a entrained flow gasifier combined with standard low-temperature gas cleanup and SOFC, resulted in an overall electrical efficiency of about 47%, and an overall efficiency close to 85%. [Copyright &y& Elsevier]

Many concerns have been raised about the mechanism of cathode reaction in molten carbonate fuel cell (MCFC). The chemical behavior of oxide species at cathode in molten carbonate is a key for understanding the process of cathode reactions. In this paper, the variety and role of the oxide species in both bulk and thin-film of basic molten carbonates were investigated by using a novel in-situ Raman spectroscopy. The results indicated that the dominant oxide species under basic conditions was peroxide ion, and it was possible to transform into the oxygen of crystalline lattice during the lithium-doped process. It was demonstrated that in-situ Raman spectroscopic technique was a promising tool to elucidate the mechanism of electrode reaction in molecular level in the MCFC condition. [Copyright &y& Elsevier]

• A hybrid MCFC-MSP-CHP was proposed and exergetically assessed. • The system produced 110.5 MW power, 271.7 kgmole/h methanol, and hot water. • Overall exergy & energy efficiencies were found 58.4 and 83.7%. • 23% of the overall exergy destruction occurred in the combustion chamber. • A thorough sensitivity analysis was performed to examine the interactive effects. The object of this paper is to develop and exergetically assess a multi-generation system comprised of a Molten Carbonate Fuel Cell (MCFC) coupled with Steam Methane Reforming (SMR), Methanol Synthesis Process (MSP) with distillation process, and combined heat and power cycle (CHP) including gas turbine, Rankine cycle (RC), Organic Rankine Cycle (ORC) and District Heating (DH) line. The combination of the MCFC, CHP and MSP can be considered as an innovative breakthrough in the field of energy systems, in light of the fact that the reforming compartment can mutually feed both MCFC and MSP, and the whole process can simultaneously produce electricity, pure methanol and hot water. The SMR at 800 kPa and 600 °C was applied to produce synthetic gas required by MCFC and MSP. The simulation was performed by Aspen Hysys, considering several operational conditions and the best was selected according to exergetic performance assessment. The structure produced 110,544 kW net electricity (34% MCFC, 33.4% gas turbine, 18.4% RC and 14.2% ORC), pure methanol (99.9%) at 271.7 kgmole/h, and hot water at 80 °C and 65398.7 kgmole/h. About 23% and 21% of the overall destructed exergy belonged to combustion chamber and MCFC, respectively. The overall exergy destruction, exergy efficiency and energy efficiency of the integrated system were obtained 116,353 kW, 58.4% and 83.7%, respectively. Finally, the performance of the proposed hybrid system was compared with similar studies and it was found that the hybrid MCFC-MSP-CHP system can outstandingly enhance the overall efficiency and reduce CO 2 emissions. [ABSTRACT FROM AUTHOR]