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

2005 ◽  
Vol 127 (1) ◽  
pp. 86-90 ◽  
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.

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

2013 ◽  
Vol 757 ◽  
pp. 217-241 ◽  
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.

scholarly journals The Exergy Costs of Electrical Power, Cooling, and Waste Heat from a Hybrid System Based on a Solid Oxide Fuel Cell and an Absorption Refrigeration System

Energies ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3476 ◽  
Author(s):  
V. Rangel-Hernandez ◽  
C. Torres ◽  
A. Zaleta-Aguilar ◽  
M. Gomez-Martinez
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Hybrid System ◽  
Waste Heat ◽  
Electrical Power ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Absorption Refrigeration ◽  
Absorption Refrigeration System ◽  
The Impact

This paper applies the Exergy Cost Theory (ECT) to a hybrid system based on a 500 kWe solid oxide fuel cell (SOFC) stack and on a vapor-absorption refrigeration (VAR) system. To achieve this, a model comprised of chemical, electrochemical, thermodynamic, and thermoeconomic equations is developed using the software, Engineering Equation Solver (EES). The model is validated against previous works. This approach enables the unit exergy costs (electricity, cooling, and residues) to be computed by a productive structure defined by components, resources, products, and residues. Most importantly, it allows us to know the contribution of the environment and of the residues to the unit exergy cost of the product of the components. Finally, the simulation of different scenarios makes it possible to analyze the impact of stack current density, fuel use, temperature across the stack, and anode gas recirculation on the unit exergy costs of electrical power, cooling, and residues.

Performance Comparison of Internal Reforming Against External Reforming in a SOFC, Gas Turbine Hybrid System

2003 ◽  
Author(s):  
Eric A. Liese ◽  
Randall S. Gemmen
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Waste Heat ◽  
Performance Comparison ◽  
Internal Reforming ◽  
Base Concept ◽  
Thermodynamic Performance ◽  
Cell Current ◽  
Hybrid Configuration ◽  
Better Than

Solid Oxide Fuel Cell (SOFC) manufacturers 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 is introduced that uses interstage external reforming. Results show that that the thermodynamic performance of an interstage reforming system is an improvement over a base-concept external approach, and may be slightly better than the hybrid with an internal reforming fuel cell.

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

2021 ◽  
Vol 9 ◽  
Author(s):  
Utkarsh Shikhar ◽  
Kas Hemmes ◽  
Theo Woudstra
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Fuel Utilization ◽  
Molten Carbonate ◽  
Internal Reforming ◽  
Molten Carbonate Fuel Cells

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.

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

2019 ◽  
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.

Sign in / Sign up

Export Citation Format

Share Document