Small Scale Reforming Separation Systems with Nanomembrane Reactors for Direct Fuel Cell Applications

2010 ◽  
Vol 12 ◽  
pp. 105-113 ◽  
Author(s):  
Savvas Vasileiadis ◽  
Zoe Ziaka
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Product Yield ◽  
Cell System ◽  
Membrane Reactors ◽  
Inorganic Membrane ◽  
Small Scale ◽  
Reaction Products ◽  
Molten Carbonate ◽  
Fuel Gas

Our recent communication focuses on small scale and nanoscale type engineering applications of alumina inorganic membrane reactors and reactor-permeator systems for the conversion of renewable and non-renewable hydrocarbons and methane rich streams into hydrogen rich gas for direct inner application and operation of fuel cell systems. This study elaborates on new nanomembrane reactors for the steam-methane/hydrocarbon reforming and water gas shift reactions, including work in the synthesis, manufacturing, modeling and operation of such microreaction systems. The projected small scale reactors, separators and overall reaction systems are of current significance in the area of multifunctional microreactor and nanoreactor design and operation in connection with the operation of fuel cells for transportation, stationary, and portable power generation applications. An added advantage of such systems is the reactive and separative operations of the fuel cell membrane-processor which are combined to convert the hydrocarbon with steam to valuable fuel gas for continuous fuel cell operation. Moreover, the nanomembrane systems under development have the unique characteristics to perform multiple operations per unit volume, such as to utilize beneficial equilibrium shift principles in reactant conversion and product yield through the removal of permselective species (i.e., hydrogen) via the inorganic membrane out of the conversion/reaction zone. In this way, improved hydrogen and product yields can be achieved which exceed the equilibrium calculated yields. Simultaneously, the reaction products, such as synthesis gas (i.e., H2, CO and CO2) at the reactor exit can be used as fuel in mostly solid oxide and molten carbonate fuel cells. The role of the alumina nanomembrane is also in the main conversion and upgrading sections of these feedstocks in order to overcome existing heat and mass transfer limitations and increase the overall efficiency of the microreactor-fuel cell system.

FULL SCALE EXPERIMENT AND NUMERICAL ANALYSIS FOR THE PERFORMANCE OF HEAT EXCHANGER IN MOLTEN CARBONATE FUEL CELLS

2016 ◽  
Vol 40 (5) ◽  
pp. 799-810
Author(s):  
Seon-Hwa Kim ◽  
Byeong-Keun Choi ◽  
Young-Su An
Keyword(s):  
Heat Exchanger ◽  
Fuel Cell ◽  
Flow Characteristics ◽  
Cell System ◽  
Molten Carbonate Fuel Cell ◽  
Molten Carbonate ◽  
Fuel Gas ◽  
Operation Conditions ◽  
Scale Down ◽  
Scale Experiment

This study presents a numerical simulation of heat transfer and flow characteristics of the heat exchanger in molten carbonate fuel cell system. In this study, the actual size of the heat exchanger was simulated in order to avoid errors that can occur from the scale-down test, also the simulation gas (air) was verified with the heat duty of 800,000 kcal/hr. It is analyzed by using a commercial heat exchanger calculation code based upon the test condition. It is found that a reasonable agreement is obtained from comparison between the predicted results and the measured data. Furthermore, the verified similarity was presented in this analysis. In particular, the simulation gas used for the shell side service for the heat exchanger is obtained through the combustion calculation, i.e. by using a flow rate of the fuel gas. In addition, the performance of the heat exchanger is predicted under various conditions in the fuel cell operation conditions by the numerical model.

Modeling of a Methane Fuelled Direct Carbon Fuel Cell System

2010 ◽  
Vol 7 (6) ◽  
Author(s):  
K. Hemmes ◽  
M. Houwing ◽  
N. Woudstra
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Cell System ◽  
Molten Carbonate Fuel Cell ◽  
Total System ◽  
Molten Carbonate ◽  
Heating Value ◽  
Carbon Particles ◽  
Direct Carbon Fuel Cell ◽  
Air Stream

Direct Carbon Fuel Cells (DCFCs) have great thermodynamic advantages over other high temperature fuel cells such as molten carbonate fuel cell (MCFC) and solid oxide fuel cell. They can have 100% fuel utilization, no Nernst loss (at the anode), and the CO2 produced at the anode is not mixed with other gases and is ready for re-use or sequestration. So far only studies have been reported on cell development. In this paper we study in particular the integration of the production of clean and reactive carbon particles from methane as a fuel for the direct carbon fuel cell. In the thermal decomposition process heat is upgraded to chemical energy in the carbon and hydrogen produced. The hydrogen is seen as a product as well as the power and heat. Under the assumptions given the net system electric efficiencies are 22.9% (based on methane lower heating value, LHV) and 20.7% (higher heating value, HHV). The hydrogen production efficiencies are 65.5% (based on methane LHV) and 59.1% (HHV), which leads to total system efficiencies of 88.4% (LHV) and 79.8% (HHV). Although a pure CO2 stream is produced at the anode outlet, which is seen as a large advantage of DCFC systems, this advantage is unfortunately reduced due to the need for CO2 in the cathode air stream. Due to the applied assumed constraint that the cathode outlet stream should at least contain 4% CO2 for the proper functioning of the cathode, similar to MCFC cathodes, a major part of the pure CO2 has to be mixed with incoming air. Further optimization of the DCFC and the system is needed to obtain a larger fraction of the output streams as pure CO2 for sequestration or re-use.

Comparative Analysis of Hybrid Cycles Based on Molten Carbonate and Solid Oxide Fuel Cells

2001 ◽  
Author(s):  
Stefano Campanari ◽  
Ennio Macchi
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Gas Turbines ◽  
Solid Oxide ◽  
Molten Carbonate Fuel Cell ◽  
Small Scale ◽  
Oxide Fuel ◽  
Molten Carbonate ◽  
Successful Operation ◽  
Hybrid Plants

High temperature fuel cells are experiencing an increasing amount of attention thanks to the successful operation of prototype plants, including a multi-MW Molten Carbonate Fuel Cell (MCFC) demonstration plant and a hybrid Solid Oxide Fuel Cell (SOFC) gas turbine power plant. Both MCFCs and SOFCs are currently considered attractive for the integration with gas turbines in more complex “hybrid” plants, with projected performances that largely exceed combined cycles efficiencies even at a small-scale size and with an extremely low environmental impact. This paper compares the performances of MCFC and SOFC hybrid cycles. The comparison shows some advantages for the SOFC hybrid cycle in terms of plant simplicity and moderately higher efficiency.

Operation of Carbonate Fuel Cell (MCFC) Using Syngas

2011 ◽  
Author(s):  
Joseph McInerney ◽  
Hossein Ghezel-Ayagh ◽  
Robert Sanderson ◽  
Jennifer Hunt
Keyword(s):  
Power Generation ◽  
Fuel Cells ◽  
Fuel Cell ◽  
Natural Gas ◽  
High Efficiency ◽  
Cell System ◽  
System Level ◽  
Molten Carbonate ◽  
Fuel Cell Stack ◽  
Internal Reforming

High temperature fuel cells, such as Molten Carbonate Fuel Cells (MCFC), are prime candidates for power generation using natural gas. Currently MCFC-based products are available for on-site power generation using natural gas and methane-rich biogas. These systems use the most advanced stack configuration utilizing internal reforming of methane. The in-situ reforming within the fuel cell anode provides many operational benefits including stack cooling at high current densities. Syngas from a variety of sources such as coal, biomass and renewables are anticipated to play a key role in the future landscape of power generation. MCFC is capable of utilizing syngss to produce electric power at a very high efficiency. However, because of the differences in the gas compositions between natural-gas and syngas, the fuel cell stack and system designs need to be modified for syngas fuels. The purpose of this study is to develop the design modifications at both the stack and system level needed for operation of internal reforming MCFC using low-methane content syngas without major design changes from the commercial product design. The net outcome of the investigation is a fuel cell system which meets the goals of being able to operate on low methane syngas within thermo-mechanical requirements of the fuel cell stack components. In this paper, we will describe the approach for modification of MCFC design and operating parameters for operation under syngas using both system level modeling and stack level mathematical modeling.

Electrochemical Carbon Separation in a SOFC-MCFC Poly-Generation Plant With Near-Zero Emissions

2017 ◽  
Author(s):  
Luca Mastropasqua ◽  
Stefano Campanari ◽  
Jack Brouwer
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Carbon Capture ◽  
Large Scale ◽  
High Efficiency ◽  
Molten Carbonate Fuel Cell ◽  
Small Scale ◽  
Total Efficiency ◽  
Molten Carbonate

High temperature fuel cells have been studied as a suitable solution for Carbon Capture and Storage (CCS) purposes at a large scale (>100 MW). However, their modularity and high efficiency at small-scale make them an interesting solution for Carbon Capture and Utilisation at the distributed generation scale when coupled to appropriate use of CO2 (i.e., for industrial uses, local production of chemicals etc.). These systems could be used within low carbon micro-grids to power small communities in which multiple power generating units of diverse nature supply multiple products such as electricity, cooling, heating and chemicals (i.e., hydrogen and CO2). The present work explores fully electrochemical power systems capable of producing a highly pure CO2 stream and hydrogen. In particular, the proposed system is based upon integrating a Solid Oxide Fuel Cell (SOFC) with a Molten Carbonate Fuel Cell (MCFC). The use of these high temperature fuel cells has already been separately applied in the past for CCS applications. However, their combined use is yet unexplored. Moreover, both industry and US national laboratories have expressed their interest in this solution. The reference configuration proposed envisions the direct supply of the SOFC anode outlet to a burner which, using the cathode depleted air outlet, completes the oxidation of the unconverted species. The outlet of the burner is then fed to the MCFC cathode inlet which separates the CO2 from the stream. Both the SOFC and MCFC anode inlets are supplied with pre-reformed and desulfurized natural gas. The MCFC anode outlet, which is characterised by a high concentration of CO2, is fed to a CO2 separation line in which a two-stage Water Gas Shift (WGS) reactor and a PSA/membrane system respectively convert the remaining CO into H2 and remove the H2 from the exhaust stream. This has the significant advantage of achieving the required CO2 purity for liquefaction and long-range transportation without requiring the need of cryogenic or distillation plants. Moreover, the highly pure H2 stream can either be sold as transportation fuel or a valuable chemical. Furthermore, different configurations are considered with the final aim of increasing the Carbon Capture Ratio (CCR) and maximising the electrical efficiency. Moreover, the optimal power ratio between SOFC and MCFC stacks is also explored. Complete simulation results are presented, discussing the proposed plant mass and energy balances and showing the most attractive configurations from the point of view of total efficiency and CCR.

scholarly journals Some CHP Options for Wood-Fired Fuel Cells

Volume 1 ◽  
2004 ◽  
Author(s):  
D. R. McIlveen-Wright ◽  
J. T. McMullan ◽  
D. J. Guiney
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Phosphoric Acid ◽  
Waste Heat ◽  
Sensitivity Analyses ◽  
Small Scale ◽  
Selling Price ◽  
Molten Carbonate ◽  
Capital Costs ◽  
Economic Analyses

The possibility of integrating biomass gasifiers with fuel cells has already been explored and shown to offer a method for using renewable energy to generate electricity at a small scale. A preliminary study of applying such a system for use in an isolated community and for several selected buildings has been made and the results of these studies reported earlier. In this study wood gasification integrated with fuel cell (WGIFC) systems in CHP configurations for five building systems with different energy demand profiles, are assessed. These are a hospital, a hotel, a leisure centre, a multi-residential community and a university hall of residence. Heat and electricity use profiles for typical examples of these buildings were obtained and the WGIFC system scaled to the power demand. Detailed technical, environmental and economic analyses of each version are made, using the ECLIPSE process simulation package. Various factors influencing the economic viability of each application are examined and a sensitivity analysis for each system produced. The WGIFC system was modelled for two different types of fuel cell, the Molten Carbonate and the Phosphoric Acid. In each case an oxygen-fired gasification system is proposed, in order to eliminate the need for a methane reformer. Technical, environmental and economic analyses of each version were made, using ECLIPSE. Since fuel cell lifetimes are not yet precisely known, economics for a range of fuel cell lifetimes have been produced. While the wood-fired Phosphoric Acid Fuel Cell (WFPAFC) system was found to have low electrical efficiency (13–16%), the wood-fired Molten Carbonate Fuel Cell (WFMCFC) system was found to be quite efficient for electricity generation (24 to 27%). Much of the waste heat could be recovered for the WFPAFC, so that the overall efficiency was 64 to 67%, and some waste heat, but potentially of higher grade, could be recovered by the WFMCFC to give an overall energy efficiency of 60 to 63%. The capital costs of both systems are still expected to be very high, but the examination of wood fuel prices, fuel cell costs, fuel cell lifetime and waste heat selling prices on the break-even selling price for electricity, as well as comparative sensitivity analyses, can help identify which other factors would have the main impacts on the system economics.

Electrochemical Carbon Separation in a SOFC–MCFC Polygeneration Plant With Near-Zero Emissions

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Luca Mastropasqua ◽  
Stefano Campanari ◽  
Jack Brouwer
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Power Systems ◽  
Carbon Capture ◽  
High Efficiency ◽  
Carbon Capture And Storage ◽  
Molten Carbonate Fuel Cell ◽  
Small Scale ◽  
Total Efficiency ◽  
Molten Carbonate

The modularity and high efficiency at small-scale make high temperature (HT) fuel cells an interesting solution for carbon capture and utilization at the distributed generation (DG) scale when coupled to appropriate use of CO2 (i.e., for industrial uses, local production of chemicals, etc.). The present work explores fully electrochemical power systems capable of producing a highly pure CO2 stream and hydrogen. In particular, the proposed system is based upon integrating a solid oxide fuel cell (SOFC) with a molten carbonate fuel cell (MCFC). The use of these HT fuel cells has already been separately applied in the past for carbon capture and storage (CCS) applications. However, their combined use is yet unexplored. The reference configuration proposed envisions the direct supply of the SOFC anode outlet to a burner which, using the cathode depleted air outlet, completes the oxidation of the unconverted species. The outlet of the burner is then fed to the MCFC cathode inlet, which separates the CO2 from the stream. This layout has the significant advantage of achieving the required CO2 purity for liquefaction and long-range transportation without requiring the need of cryogenic or distillation plants. Furthermore, different configurations are considered with the final aim of increasing the carbon capture ratio (CCR) and maximizing the electrical efficiency. Moreover, the optimal power ratio between SOFC and MCFC stacks is also explored. Complete simulation results are presented, discussing the proposed plant mass and energy balances and showing the most attractive configurations from the point of view of total efficiency and CCR.

scholarly journals Stacking Up

2003 ◽  
Vol 125 (06) ◽  
pp. 36-39 ◽  
Author(s):  
Michael R. Von Spakovsky
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Clean Energy ◽  
Proton Exchange ◽  
Small Scale ◽  
Molten Carbonate ◽  
Cell Systems ◽  
Exhaust Heat ◽  
The Future

This article reviews that efficiency on a small scale and a means of curbing emissions make fuel cells an investment for the future. The Connecticut Clean Energy Fund put up the $1.25 million to purchase the fuel cell-power plant from a local company, Fuel Cell Energy Inc., in Danbury. The motive for funding fuel cells goes beyond boosting for local industry, though. As pressures mount on available resources and the environment, fuel cell systems can play a major role in the future of stationary and mobile power generation. Many adherents believe that fuel cell systems promise to provide benefits in a variety of applications. Systems based on PEM and direct methanol technology promise to make power more portable and convenient, and proton exchange membrane (PEM) technology also promises to provide a more efficient, cleaner technology for the automotive industry. PEM, phosphoric acid, molten carbonate, and solid oxide fuel cells are likely to be applied in cogeneration applications that use the exhaust heat.

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