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.

Gasification and Fuel Cell Integration With Bottoming Turbine Cycle: Performances of a Hybrid Plant for Electricity Production

2003 ◽  
Author(s):  
P. Lunghi ◽  
R. Burzacca
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Energy Production ◽  
Waste Heat ◽  
Molten Carbonate Fuel Cell ◽  
Sensitivity Analyses ◽  
Electricity Production ◽  
Operating Pressure ◽  
Molten Carbonate ◽  
Gasification Process

The increasing need of energy resources along with the growing environmental interest promote the creation of new concepts in the field of energy production and management strategies. The development of high temperature fuel cells, suitable for stationary energy production, is one of the most promising aspects, able to bring a significant change in the power generation scenario. One of the most important features for fuel cells is the potential coupling with advanced gasification systems, thus enabling the possibility of energy recovery from waste, RDF (Refuse Derived Fuel) and biomass. The gasification process transfers the energetic value of the original solid fuel to a gaseous product rich in hydrogen, carbon monoxide and dioxide, and other compounds. A post-gasification treatment removes tars, particulates, impurities and makes the gas suitable for power production in a fuel cell unit. In this work an example of an innovative plant for biomass utilization has been considered. The plant includes a gasification section and a Molten Carbonate Fuel Cell unit, coupled with a hot gas cleanup system. For gasification technology, a recent typology was considered involving an indirect heating system such as the Battelle process. Gaseous streams conveyed to the cell after the conditioning processes were considered. In order to achieve higher efficiencies, a bottoming cycle has been added. It comprises a turbine power plant integrated with the gasification and fuel cell lay-out. In the turbine cycle air is compressed in the operating pressure and internally heated by the waste heat of the fuel cell and of the gasification process. The expanded air is then used in the combustion reactor of the gasification system. The proposed plant allows high electric efficiency and high flexibility in choosing for air compression ratio and unit size; sensitivity analyses were performed.

Conversion of Syngas From Biomass in Solid Oxide Fuel Cells

2006 ◽  
Author(s):  
Ju¨rgen Karl ◽  
Nadine Frank ◽  
Sotiris Karellas ◽  
Mathilde Saule ◽  
Ulrich Hohenwarter
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Liquid Metal ◽  
Waste Heat ◽  
Heat Pipes ◽  
Economic Feasibility ◽  
Small Scale ◽  
Cell Systems ◽  
Exhaust Heat ◽  
Integrated Gasification

Conversion of biomass in syngas by means of indirect gasification offers the option to improve the economic situation of any fuel cell systems due to lower costs for feedstock and higher power revenues in many European countries. The coupling of an indirect gasification of biomass and residues with highly efficient SOFC systems is therefore a promising technology for reaching economic feasibility of small decentralized combined heat and power production (CHP). The predicted efficiency of common high temperature fuel cell systems with integrated gasification of solid feedstock is usually significantly lower than the efficiency of fuel cells operated with hydrogen or methane. Additional system components like the gasifier, as well as the gas cleaning reduce this efficiency. Hence common fuel cell systems with integrated gasification of biomass will hardly reach electrical efficiencies above 30 percent. An extraordinary efficient combination is achieved in case that the fuel cells waste heat is used in an indirect gasification system. A simple combination of a SOFC and an allothermal gasifier enables then electrical efficiencies above 50%. But this systems requires an innovative cooling concept for the fuel cell stack. Another significant question is the influence of impurities on the fuel cells degradation. The European Research Project ‘BioCellus’ focuses on both questions — the influence of the biogenious syngas on the fuel cells and an innovative cooling concept based on liquid metal heat pipes. First experiments showed that in particular higher hydrocarbons — the so-called tars — do not have an significant influence on the performance of SOFC membranes. The innovative concept of the TopCycle comprises to heat an indirect gasifier with the exhaust heat of the fuel cell by means of liquid metal heat pipes. Internal cooling of the stack and the recirculation of waste heat increases the system efficiency significantly. This concept promises electrical efficiencies of above 50 percent even for small-scale systems without any combined processes.

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.

Performance Analysis on SOFC-HCCI Engine Hybrid System

2012 ◽  
Author(s):  
Sung Ho Park ◽  
Young Duk Lee ◽  
Sang Gyu Kang ◽  
Kook Young Ahn
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Hybrid Systems ◽  
Hybrid System ◽  
Gas Turbines ◽  
Waste Heat ◽  
Metal Catalyst ◽  
Molten Carbonate ◽  
Hcci Engine ◽  
Ci Engines

Fuel cell systems are currently regarded as a promising type of energy conversion system. Various types of fuel cell have been developed and investigated worldwide for portable, automotive, and stationary applications. In particular, in the case of large-scale stationary applications, the high-temperature fuel cells known as the molten carbonate fuel cell (MCFC) and the solid oxide fuel cell (SOFC) have been used as a power source due to their higher efficiency compared to low-temperature fuel cells. Because SOFCs have many advantages, including a high power density, low corrosion, and operability without a metal catalyst, many efforts to develop a SOFC hybrid system have been undertaken. SOFC hybrid systems with a gas turbine or engine show improved system efficiency through their utilization of waste heat and unreacted fuel. Especially, the internal combustion engine has the advantage of robustness, easy maintenance, and a low cost compared to gas turbines, this type is more adaptable for use in a hybrid system with a SOFC. However, the engine should be operated stably at a high air fuel ratio because the SOFC anode exhaust gas has a low fuel concentration. The homogeneous charge compression ignition (HCCI) engine has both the advantages of SI and CI engines. Moreover, the lean burn characteristics of the HCCI engine make it a strong candidate for SOFC hybrid systems. The objective of this work is to develop a novel cycle composed of a SOFC and a HCCI engine. In order to optimize the SOFC-HCCI hybrid system, a system analysis is conducted here using the commercial software Aspen Plus®. The SOFC model is validated with experimental data. The engine model is developed based on an empirical equation that considers the ignition delay time. The performance of the hybrid system is compared with that of a SOFC stand-alone system to confirm the optimization of the system. This study will be useful for the development of a new type of hybrid system which uses a fuel cell and an optimized system.

Power Cycle Integration and Efficiency Increase of Molten Carbonate Fuel Cell Systems

2005 ◽  
Vol 3 (4) ◽  
pp. 375-383 ◽  
Author(s):  
Petar Varbanov ◽  
Jiří Klemeš ◽  
Ramesh K. Shah ◽  
Harmanjeet Shihn
Keyword(s):  
Fuel Cells ◽  
High Temperature ◽  
Fuel Cell ◽  
Gas Turbines ◽  
Waste Heat ◽  
Combined Cycle ◽  
Molten Carbonate Fuel Cell ◽  
Steam Turbines ◽  
Molten Carbonate ◽  
Carbonate Fuel Cell

A new view is presented on the concept of the combined cycle for power generation. Traditionally, the term “combined cycle” is associated with using a gas turbine in combination with steam turbines to better utilize the exergy potential of the burnt fuel. This concept can be broadened, however, to the utilization of any power-generating facility in combination with steam turbines, as long as this facility also provides a high-temperature waste heat. Such facilities are high temperature fuel cells. Fuel cells are especially advantageous for combined cycle applications since they feature a remarkably high efficiency—reaching an order of 45–50% and even close to 60%, compared to 30–35% for most gas turbines. The literature sources on combining fuel cells with gas and steam turbines clearly illustrate the potential to achieve high power and co-generation efficiencies. In the presented work, the extension to the concept of combined cycle is considered on the example of a molten carbonate fuel cell (MCFC) working under stationary conditions. An overview of the process for the MCFC is given, followed by the options for heat integration utilizing the waste heat for steam generation. The complete fuel cell combined cycle (FCCC) system is then analyzed to estimate the potential power cost levels that could be achieved. The results demonstrate that a properly designed FCCC system is capable of reaching significantly higher efficiency compared to the standalone fuel cell system. An important observation is that FCCC systems may result in economically competitive power production units, comparable with contemporary fossil power stations.

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.

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.

Conversion of Syngas From Biomass in Solid Oxide Fuel Cells

2009 ◽  
Vol 6 (2) ◽  
Author(s):  
Jurgen Karl ◽  
Nadine Frank ◽  
Sotirios Karellas ◽  
Mathilde Saule ◽  
Ulrich Hohenwarter
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Liquid Metal ◽  
Waste Heat ◽  
Heat Pipes ◽  
Solid Oxide ◽  
Small Scale ◽  
Oxide Fuel ◽  
Cell Systems ◽  
Integrated Gasification

Conversion of biomass in syngas by means of indirect gasification offers the option to improve the economic situation of any fuel cell system due to lower costs for feedstock and higher power revenues in many European countries. The coupling of an indirect gasification of biomass and residues with highly efficient solid oxide fuel cell (SOFC) systems is therefore a promising technology for reaching economic feasibility of small decentralized combined heat and power production (CHP).The predicted efficiency of common high temperature fuel cell systems with integrated gasification of solid feedstock is usually significantly lower than the efficiency of fuel cells operated with hydrogen or methane. Additional system components like the gasifier as well as the gas cleaning reduce this efficiency. Hence common fuel cell systems with integrated gasification of biomass will hardly reach electrical efficiencies above 30%. An extraordinary efficient combination is achieved in case that the fuel cells waste heat is used in an indirect gasification system. A simple combination of a SOFC and an allothermal gasifier enables then electrical efficiencies above 50%. However, this system requires an innovative cooling concept for the fuel cell stack. Another significant question is the influence of impurities on the fuel cell degradation. The European Research Project “BioCellus” focuses on both questions—the influence of the biogenous syngas on the fuel cells and an innovative cooling concept based on liquid metal heat pipes. First experiments showed that, in particular, higher hydrocarbons—the so-called tars—do not have any significant influence on the performance of SOFC membranes. The innovative concept of the TopCycle comprises to heat an indirect gasifier with the exhaust heat of the fuel cell by means of liquid metal heat-pipes. Internal cooling of the stack and the recirculation of waste heat increases the system efficiency significantly. This concept promises electrical efficiencies of above 50% even for small-scale systems without any combined processes.

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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