Optimization of a MCFC Hybrid System for Combined Production of Electricity and Hydrogen

2009 ◽  
Author(s):  
Vittorio Verda ◽  
Flavio Nicolin
Keyword(s):  
Fuel Cell ◽  
Unit Cost ◽  
Hybrid Plant ◽  
Operating Conditions ◽  
Molten Carbonate Fuel Cell ◽  
Molten Carbonate ◽  
Fuel Cell Performance ◽  
Micro Gas Turbine ◽  
Pressure Swing ◽  
Economic Objective

In this paper, a hybrid plant obtained by integrating a molten carbonate fuel cell stack with a micro gas turbine and a steam reformer is considered. The system also produces hydrogen through a pressure swing absorption system. The aim of this work is the multi-objective optimisation of the system, considering energy and economic objective functions. Possible off-design operating conditions accounting for degradation of the fuel cell performance and time variation in the biogas composition are considered, as well as variation in the ambient temperature. The results show that the operating temperature of the fuel cell is a crucial design parameter as its value strongly affects the plant efficiency, its lifetime and the unit cost of electricity.

Thermo-Kinetic Representation and Transient Simulation of a Molten Carbonate Fuel Cell

2005 ◽  
Author(s):  
Brian C. Carroll ◽  
Thomas M. Kiehne ◽  
Michael D. Lukas
Keyword(s):  
Fuel Cell ◽  
Cell Model ◽  
Operating Conditions ◽  
Molten Carbonate Fuel Cell ◽  
System Level ◽  
Transient Temperature ◽  
Molten Carbonate ◽  
Fuel Cell Performance ◽  
Fuel Reformation ◽  
Carbonate Fuel Cell

There are a growing number of models in the literature dealing with the transient behavior of fuel cells. However, few, if any, employ fundamental kinetic theory to model the fuel reformation process while simultaneously simulating fuel cell behavior from a transient, system-level perspective. Thus a comprehensive, transient fuel cell model has been developed that includes all the relevant thermodynamics, chemistry, and electrical characteristics of actual fuel cell operation. The model tracks the transient temperature response of a fuel cell stack, chemical specie concentrations of exhaust gases, efficiency of the fuel reformation equipment, and electrical output characteristics. Model results provide a concise, parametric evaluation of the influence of operating conditions and user-controlled parameters on fuel cell performance. The model is validated against transient Molten Carbonate fuel cell (MCFC) data from a subscale stack.

Performance Evaluation of a Molten Carbonate Fuel Cell/Micro Gas Turbine Hybrid System With Oxy-Combustion Carbon Capture

2017 ◽  
Author(s):  
Ji Ho Ahn ◽  
Tong Seop Kim
Keyword(s):  
Carbon Dioxide ◽  
Fuel Cell ◽  
Gas Turbine ◽  
Hybrid System ◽  
Carbon Capture ◽  
Molten Carbonate Fuel Cell ◽  
Design Parameters ◽  
Molten Carbonate ◽  
Micro Gas Turbine ◽  
Carbonate Fuel Cell

Owing to the increasing consumption of fossil fuels and emission of greenhouse gases, interests in highly efficient and low carbon emitting power systems are growing fast. Several research groups have been suggesting advanced systems based on fuel cells and have also been applying carbon capture and storage technology to satisfy the demand for clean energy. In this study, the performance of a hybrid system, which is a combination of a molten carbonate fuel cell (MCFC) with oxy-combustion carbon capture and an indirectly fired micro gas turbine (MGT) was predicted. A 2.5MW MCFC system that is used in commercial applications was used as the reference system so that the results of the study could be applicable to practical situations. The ambient pressure type hybrid system was modeled by referring to the design parameters of an MGT that is currently being developed. A semi-closed type design characterized by flow recirculation was adopted for this hybrid system. A part of the recirculating gas is converted into liquefied carbon dioxide and captured for storage at the carbon separation unit. Almost 100% carbon dioxide capture is possible with this system. In these systems, the output power of the fuel cell is larger than in the normal hybrid system without carbon capture because the partial pressure of carbon dioxide increases. The increased cell power partially compensates for the power loss due to the carbon capture and MGT power reduction. The dependence of net system efficiency of the oxy-hybrid on compressor pressure ratio is marginal, especially beyond an optimal value.

Performance Evaluation of a Molten Carbonate Fuel Cell/Micro Gas Turbine Hybrid System With Oxy-Combustion Carbon Capture

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Ji Ho Ahn ◽  
Tong Seop Kim
Keyword(s):  
Carbon Dioxide ◽  
Fuel Cell ◽  
Gas Turbine ◽  
Hybrid System ◽  
Carbon Capture ◽  
Molten Carbonate Fuel Cell ◽  
Design Parameters ◽  
Molten Carbonate ◽  
Micro Gas Turbine ◽  
Carbonate Fuel Cell

Owing to the increasing consumption of fossil fuels and emission of greenhouse gases, interests in highly efficient and low carbon emitting power systems are growing fast. Several research groups have been suggesting advanced systems based on fuel cells and have also been applying carbon capture and storage technology to satisfy the demand for clean energy. In this study, the performance of a hybrid system, which is a combination of a molten carbonate fuel cell (MCFC) with oxy-combustion carbon capture and an indirectly fired micro gas turbine (MGT), was predicted. A 2.5 MW MCFC system that is used in commercial applications was used as the reference system so that the results of the study could be applied to practical situations. The ambient pressure type hybrid system was modeled by referring to the design parameters of an MGT that is currently being developed. A semi-closed type design characterized by flow recirculation was adopted for this hybrid system. A part of the recirculating gas is converted into liquefied carbon dioxide and captured for storage at the carbon separation unit (CSU). Almost 100% carbon dioxide capture is possible with this system. In these systems, the output power of the fuel cell is larger than in the normal hybrid system without carbon capture because the partial pressure of carbon dioxide increases. The increased cell power partially compensates for the power loss due to the carbon capture and MGT power reduction. The dependence of net system efficiency of the oxy-hybrid on compressor pressure ratio is marginal, especially beyond an optimal value.

Performance Enhancement of a Molten Carbonate Fuel Cell/Micro Gas Turbine Hybrid System With Carbon Capture by Off-Gas Recirculation

2018 ◽  
Author(s):  
Ji Ho Ahn ◽  
Ji Hun Jeong ◽  
Tong Seop Kim
Keyword(s):  
Fuel Cell ◽  
Gas Turbine ◽  
Hybrid System ◽  
Carbon Capture ◽  
Molten Carbonate Fuel Cell ◽  
Human Society ◽  
Molten Carbonate ◽  
Micro Gas Turbine ◽  
Gas Recirculation ◽  
Carbonate Fuel Cell

The demand for clean energy continues to increase as the human society becomes more aware of environmental challenges such as global warming. Various power systems based on high-temperature fuel cells have been proposed, especially hybrid systems combining a fuel cell with a gas turbine, and research on carbon capture and storage technology to prevent the emission of greenhouse gases is already underway. This study suggests a new method to innovatively enhance the efficiency of a molten carbonate fuel cell/micro gas turbine hybrid system including carbon capture. The key technology adopted to improve the net cycle efficiency is off-gas recirculation. The hybrid system incorporating oxy-combustion capture was devised, and its performance was compared with that of a post-combustion system based on a hybrid system. A molten carbonate fuel cell system based on a commercial unit was modeled. Externally supplied water for reforming was not needed as a result of the presence of the water vapor in the recirculated anode off-gas. The analyses confirmed that the thermal efficiencies of all the systems (MCFC stand-alone, hybrid, hybrid with oxy-combustion capture, hybrid with post-combustion capture) were significantly improved by introducing the off-gas recirculation. In particular, the largest efficiency improvement was observed for the oxy-combustion hybrid system. Its efficiency is over 57% and is even higher than that of the post-combustion hybrid system.

Off-Design Performance Analysis of a Hybrid System Based on an Existing Molten Fuel Cell Stack

2003 ◽  
Vol 125 (4) ◽  
pp. 986-993 ◽  
Author(s):  
P. Bedont ◽  
O. Grillo ◽  
A. F. Massardo
Keyword(s):  
Fuel Cell ◽  
Gas Turbine ◽  
Hybrid System ◽  
Load Condition ◽  
Molten Carbonate Fuel Cell ◽  
Molten Carbonate ◽  
Utilization Factor ◽  
Micro Gas Turbine ◽  
Fixed Design ◽  
Stack Model

This paper addresses the off-design analysis of a hybrid system (HS) based on the coupling of an existing Ansaldo Fuel Cells (formerly Ansaldo Ricerche) molten carbonate fuel cell (MCFC) stack (100 kW) and a micro gas turbine. The MCFC stack model at fixed design conditions has previously been presented by the authors. The present work refers to an off-design stack model, taking into account the influence of the reactor layout, current density, air and fuel utilization factor, CO2 recycle loop, cell operating temperature, etc. Finally, the design and off-design model of the whole hybrid system is presented. Efficiency at part load condition is presented and discussed, taking into account all the constraints for the stack and the micro gas turbine, with particular emphasis on CO2 recycle control.

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