Exploring the Possibility of Using Molten Carbonate Fuel Cell for the Flexible Coproduction of Hydrogen and Power

Fuel cells are electrochemical devices that are conventionally used to convert the chemical energy of fuels into electricity while producing heat as a byproduct. High temperature fuel cells such as molten carbonate fuel cells and solid oxide fuel cells produce significant amounts of heat that can be used for internal reforming of fuels such as natural gas to produce gas mixtures which are rich in hydrogen, while also producing electricity. This opens up the possibility of using high temperature fuel cells in systems designed for flexible coproduction of hydrogen and power at very high system efficiency. In a previous study, the flowsheet software Cycle-Tempo has been used to determine the technical feasibility of a solid oxide fuel cell system for flexible coproduction of hydrogen and power by running the system at different fuel utilization factors (between 60 and 95%). Lower utilization factors correspond to higher hydrogen production while at a higher fuel utilization, standard fuel cell operation is achieved. This study uses the same basis to investigate how a system with molten carbonate fuel cells performs in identical conditions also using Cycle-Tempo. A comparison is made with the results from the solid oxide fuel cell study.

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Performance Comparison of Internal Reforming Against External Reforming in a Solid Oxide Fuel Cell, Gas Turbine Hybrid System

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.1788689 ◽

2005 ◽

Vol 127 (1) ◽

pp. 86-90 ◽

Cited By ~ 20

Author(s):

Eric A. Liese ◽

Randall S. Gemmen

Keyword(s):

Fuel Cells ◽

Fuel Cell ◽

Solid Oxide Fuel Cell ◽

Hybrid System ◽

Waste Heat ◽

Performance Comparison ◽

Solid Oxide ◽

Oxide Fuel ◽

Internal Reforming ◽

Hybrid Configuration

Solid Oxide Fuel Cell (SOFC) developers are presently considering both internal and external reforming fuel cell designs. Generally, the endothermic reforming reaction and excess air through the cathode provide the cooling needed to remove waste heat from the fuel cell. Current information suggests that external reforming fuel cells will require a flow rate twice the amount necessary for internal reforming fuel cells. The increased airflow could negatively impact system performance. This paper compares the performance among various external reforming hybrid configurations and an internal reforming hybrid configuration. A system configuration that uses the reformer to cool a cathode recycle stream is introduced, and a system that uses interstage external reforming is proposed. Results show that the thermodynamic performance of these proposed concepts are an improvement over a base-concept external approach, and can be better than an internal reforming hybrid system, depending on the fuel cell cooling requirements.

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Solid Oxide Fuel Cell - A Future Source of Power and Heat Generation

Materials Science Forum ◽

10.4028/www.scientific.net/msf.757.217 ◽

2013 ◽

Vol 757 ◽

pp. 217-241 ◽

Cited By ~ 5

Author(s):

Pankaj Kalra ◽

Rajeev Garg ◽

Ajay Kumar

Keyword(s):

Fuel Cells ◽

Fuel Cell ◽

Solid Oxide Fuel Cell ◽

Internal Combustion Engines ◽

Electrical Energy ◽

Solid Oxide ◽

Intermediate Step ◽

Oxide Fuel ◽

Power Sources ◽

Internal Reforming

Fuel cells are devices for electrochemically converting the chemical energy of a fuel gas into electrical energy and heat without the need for direct combustion as an intermediate step. The main advantages of fuel cells are that they rely on the high conversion efficiency and low environmental impact than traditional energy conversion systems. One promising fuel cell type, Solid oxide Fuel Cell, has all the components in the solid phase utilises nano-ceramic composite materials and operates at elevated temperatures in the range 500-1000°C. It has suitable perspectives to replace their classical counterparts for the distributed generation of electrical energy with small and medium power sources. The inherent advantages of such high temperature fuel cells are internal reforming of methane and waste heat production at high temperatures which lower the demands on the fuel processing system and lead to higher efficiency compared with low temperature fuel cells. Using natural gas as feed, an electric efficiency of more than 88% has been predicted. On the other hand, considerable research is going on to reduce the operating temperatures between 600°C to 800°C to increase life-time and thereby reduce costs. These can be achieved only by using electrolytes with proper ionic conductivity at the intermediate temperatures. In addition, this technology does not produce significant amounts of pollutants such as nitrogen oxides compared with internal combustion engines. Solid oxide fuel cells are seen as ideal energy sources in transport, stationary, and distributed power generators.

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Performance Comparison of Internal and External Reforming for Hybrid SOFC-GT Applications by Using 1D Real-Time Fuel Cell Mode

Volume 3: Coal, Biomass, Hydrogen, and Alternative Fuels; Cycle Innovations; Electric Power; Industrial and Cogeneration; Organic Rankine Cycle Power Systems ◽

10.1115/gt2019-91920 ◽

2019 ◽

Cited By ~ 1

Author(s):

Hao Chen ◽

Chen Yang ◽

Nana Zhou ◽

Nor Farida Harun ◽

David Tucker

Keyword(s):

Fuel Cells ◽

Fuel Cell ◽

Natural Gas ◽

Solid Oxide Fuel Cells ◽

Real Time ◽

Hybrid System ◽

Solid Oxide ◽

Oxide Fuel ◽

Fuel Utilization ◽

Internal Reforming

Abstract Solid oxide fuel cells integrated with gas turbine (SOFC-GT) systems are considered among the most promising power generation units, not only because of the high efficiency, low emissions and carbon capture ability, but also the flexibility to use different kinds of fuels such as natural gas, syngas and biogas directly. In the case of natural gas, Previous researches have demonstrated that solid oxide fuel cells possess the ability to utilize natural gas directly by reforming it inside the anode because of the high operating temperature. But the major problem of internal reforming is that it increases the temperature gradient at the leading edge of fuel cell which may lead to high thermal stress and damage the cells. On the other side, external reforming requires an additional reformer outside of fuel cell, which may increase the investment costs. Also, the amount of air needed to cool the fuel cell is doubled, compared with internal reforming. A full comparison between internal reforming and external reforming of the pressurized SOFC is needed for the hybrids application. In this paper, a real time equilibrium reformer model based on minimization of Gibbs free energy was built to couple with 1D real time solid oxide fuel cell model. An internal on-anode reforming SOFC stack configuration for hybrid SOFC-GT system application was compared with external reforming configurations with 800K, 900K and 1000K reforming temperatures. The results show that internal reforming provides better performance of SOFC stack in the case of high fuel utilization. However, the external reforming showed a higher stack efficiency and smaller stack size compared with on-anode reforming when keeping a relatively lower SOFC stack fuel utilization, necessarily for high hybrid efficiency. Results indicated that external and internal reforming of fuel needs to be optimized depending on different design conditions of the entire hybrid system in terms of efficiency and investment cost. This paper shows that the hybrid system provides the opportunities for thermal integration on performance and efficiency improvement over fuel cell anode reforming.

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Gas Turbine Cycles With Solid Oxide Fuel Cells—Part II: A Detailed Study of a Gas Turbine Cycle With an Integrated Internal Reforming Solid Oxide Fuel Cell

Journal of Energy Resources Technology ◽

10.1115/1.2906459 ◽

1994 ◽

Vol 116 (4) ◽

pp. 312-318 ◽

Cited By ~ 19

Author(s):

S. P. Harvey ◽

H. J. Richter

Keyword(s):

Power Generation ◽

Fuel Cells ◽

High Temperature ◽

Fuel Cell ◽

Solid Oxide Fuel Cells ◽

Solid Oxide Fuel Cell ◽

Energy Conversion ◽

Gas Turbine ◽

Solid Oxide ◽

Oxide Fuel

In conventional energy conversion processes, the fuel combustion is usually highly irreversible, and is thus responsible for the low overall efficiency of the power generation process. The energy conversion efficiency can be improved if immediate contact of air and fuel is prevented. One means to prevent this immediate contact is the use of fuel cell technology. Significant research is currently being undertaken to develop fuel cells for large-scale power production. High-temperature solid oxide fuel cells (SOFC) have many features that make them attractive for utility and industrial applications. However, in view of their high operating temperatures and the incomplete nature of the fuel oxidation process, such fuel cells must be combined with conventional power generation technology to develop power plant configurations that are both functional and efficient. Most fuel cell cycles proposed in the literature use a high-temperature fuel cell running at ambient pressure and a steam bottoming cycle to recover the waste heat generated by the fuel cell. With such cycles, the inherent flexibility and shorter start-up time characteristics of the fuel cell are lost. In Part I of this paper (Harvey and Richter, 1994), a pressurized cycle using a solid oxide fuel cell and an integrated gas turbine bottoming cycle was presented. The cycle is simpler than most cycles with steam bottoming cycles and more suited to flexible power generation. In this paper, we will discuss this cycle in more detail, with an in-depth discussion of all cycle component characteristics and losses. In particular, we will make use of the fuel cell’s internal fuel reforming capability. The optimal cycle parameters were obtained based on calculations performed using Aspen Technology’s ASPEN PLUS process simulation software and a fuel cell simulator developed by Argonne National Laboratory (Ahmed et al., 1991). The efficiency of the proposed cycle is 68.1 percent. A preliminary economic assessment of the cycle shows that it should compare favorably with a state-of-the-art combined cycle plant on a cost per MWe basis.

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Integrated Cr and S poisoning of a La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) cathode for solid oxide fuel cells

RSC Advances ◽

10.1039/d0ra09239h ◽

2021 ◽

Vol 11 (1) ◽

pp. 7-14

Author(s):

Cheng Cheng Wang ◽

Mortaza Gholizadeh ◽

Bingxue Hou ◽

Xincan Fan

Keyword(s):

Fuel Cells ◽

Fuel Cell ◽

Solid Oxide Fuel Cells ◽

Solid Oxide Fuel Cell ◽

Solid Oxide ◽

Cell Performance ◽

Oxide Fuel ◽

Performance Deterioration

Strontium segregation in a La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) electrode reacts with Cr and S in a solid oxide fuel cell (SOFC), which can cause cell performance deterioration.

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Coupling effects of fuel reforming process and fuel utilization on the system performance of a natural gas solid oxide fuel cell/gas turbine hybrid system

International Journal of Energy Research ◽

10.1002/er.7006 ◽

2021 ◽

Author(s):

Hao Chen ◽

Chen Yang ◽

Biao Zhang ◽

Nana Zhou ◽

Nor Farida Harun ◽

...

Keyword(s):

Fuel Cell ◽

Natural Gas ◽

Solid Oxide Fuel Cell ◽

Gas Turbine ◽

Hybrid System ◽

System Performance ◽

Solid Oxide ◽

Oxide Fuel ◽

Fuel Utilization ◽

Fuel Reforming

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A robust and active hybrid catalyst for facile oxygen reduction in solid oxide fuel cells

Energy & Environmental Science ◽

10.1039/c6ee03656b ◽

2017 ◽

Vol 10 (4) ◽

pp. 964-971 ◽

Cited By ~ 90

Author(s):

Yu Chen ◽

Yan Chen ◽

Dong Ding ◽

Yong Ding ◽

YongMan Choi ◽

...

Keyword(s):

Fuel Cells ◽

Fuel Cell ◽

Solid Oxide Fuel Cells ◽

Solid Oxide Fuel Cell ◽

Oxygen Reduction ◽

Electrocatalytic Activity ◽

Solid Oxide ◽

Oxide Fuel ◽

Hybrid Catalyst ◽

Fuel Cell Cathode

A hybrid catalyst coating dramatically enhances the electrocatalytic activity and durability of a solid oxide fuel cell cathode.

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Application of an Anode Model to Investigate Physical Parameters in an Internal Reforming Solid-Oxide Fuel Cell

Journal of Fuel Cell Science and Technology ◽

10.1115/1.1895925 ◽

2005 ◽

Vol 2 (2) ◽

pp. 136-140 ◽

Cited By ~ 8

Author(s):

Eric S. Greene ◽

Maria G. Medeiros ◽

Wilson K. S. Chiu

Keyword(s):

Fuel Cell ◽

Solid Oxide Fuel Cell ◽

Structural Parameters ◽

Porous Electrode ◽

Cell Voltage ◽

Solid Oxide ◽

Physical Parameters ◽

Oxide Fuel ◽

Internal Reforming ◽

Porous Anode

A one-dimensional model of chemical and mass transport phenomena in the porous anode of a solid-oxide fuel cell, in which there is internal reforming of methane, is presented. Macroscopically averaged porous electrode theory is used to model the mass transfer that occurs in the anode. Linear kinetics at a constant temperature are used to model the reforming and shift reactions. Correlations based on the Damkohler number are created to relate anode structural parameters and thickness to a nondimensional electrochemical conversion rate and cell voltage. It is shown how these can be applied in order to assist the design of an anode.

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