Decentralized combined heat and power production by two-stage biomass gasification and solid oxide fuel cells

To investigate options for increasing the electrical efficiency of decentralized combined heat and power (CHP) plants fuelled with biomass compared to conventional technology, this research explored the performance of an alternative plant design based on thermal biomass gasification and solid oxide fuel cells (SOFC). Based on experimental data from a demonstrated 0.6 MWth two-stage gasifier, a model of the gasifier plant was developed and calibrated. Similarly, an SOFC model was developed using published experimental data. Simulation of a 3 MWth plant combining two-stage biomass gasification and SOFCs predicted a net electrical efficiency of 44.9% (LHV (lower heating value)) when 1.4 MWe power was produced. The work had significant focus on providing a highly accurate model of the complete plant. A sensitivity analysis revealed that the SOFC operating temperature, SOFC fuel utilization factor, carbon conversion factor in the gasifier and the efficiency of the DC/AC inverter were the most influential parameters in the model. Thus, a detailed study of the practical values of these parameters was conducted to determine the performance of the plant with the lowest possible uncertainty. The SOFC fuel utilization will in practice be based on a balance between efficiency and lifetime of the SOFC and is thus a decision of the plant design.

[1]  Masoud Rokni,et al.  Thermodynamic Performance Study of Biomass Gasification, Solid Oxide Fuel Cell and Micro Gas Turbine Hybrid Systems , 2010 .

[2]  Brian Elmegaard,et al.  DNA – A General Energy System Simulation Tool , 2005 .

[3]  R. Kee,et al.  A general mathematical model for analyzing the performance of fuel-cell membrane-electrode assemblies , 2003 .

[4]  Kyriakos D. Panopoulos,et al.  Integrated CHP with autothermal biomass gasification and SOFC–MGT , 2008 .

[5]  Emmanuel Kakaras,et al.  High temperature solid oxide fuel cell integrated with novel allothermal biomass gasification: Part II: Exergy analysis , 2006 .

[6]  Nigel P. Brandon,et al.  Modelling system efficiencies and costs of two biomass-fuelled SOFC systems , 2004 .

[7]  E. Kakaras,et al.  Exergetic analysis of solid oxide fuel cell and biomass gasification integration with heat pipes , 2008 .

[8]  Emmanuel Kakaras,et al.  High temperature solid oxide fuel cell integrated with novel allothermal biomass gasification: Part I: Modelling and feasibility study , 2006 .

[9]  J. Smith,et al.  Introduction to chemical engineering thermodynamics , 1949 .

[10]  Elfinn Larsen,et al.  High tar reduction in a two-stage gasifier , 2000 .

[11]  Brian Elmegaard,et al.  Exergy analysis and optimization of a biomass gasification, solid oxide fuel cell and micro gas turbine hybrid system. , 2011 .

[12]  U. Hohenwarter,et al.  High temperature electrolyte supported Ni-GDC/YSZ/LSM SOFC operation on two-stage Viking gasifier product gas , 2007 .

[13]  Sotirios Karellas,et al.  An innovative biomass gasification process and its coupling with microturbine and fuel cell systems , 2008 .

[14]  Jai-Woh Kim,et al.  The Effect of Anode Thickness on the Performance of Anode-Supported Solid Oxide Fuel Cells , 1999 .

[15]  Tilman J. Schildhauer,et al.  Biomass-integrated gasification fuel cell systems – Part 1: Definition of systems and technical analysis , 2009 .

[16]  Brian Elmegaard,et al.  Thermodynamic analysis of small-scale dimethyl ether (DME) and methanol plants based on the efficien , 2011 .

[17]  Mogens Bjerg Mogensen,et al.  Solid Oxide Fuel Cell (SOFC) Development in Denmark , 2007 .

[18]  Mogens Bjerg Mogensen,et al.  Solid oxide fuel cell development at Topsoe Fuel Cell and Risø , 2006 .

[19]  Torben Kvist Jensen,et al.  Validation of a continuous combined heat and power (CHP) operation of a two-stage biomass gasifier , 2006 .

[20]  Tak-Hyoung Lim,et al.  Operating characteristics of a 5 kW class anode-supported planar SOFC stack for a fuel cell/gas turbine hybrid system , 2008 .

[21]  Tilman J. Schildhauer,et al.  Biomass-integrated gasification fuel cell systems - Part 2: Economic analysis , 2009 .

[22]  N. Woudstra,et al.  Alternative system designs of biomass gasification SOFC/GT hybrid systems , 2011 .

[23]  Vincenzo Antonucci,et al.  Thermodynamic analysis of SOFC fuelled by biomass-derived gas , 1994 .

[24]  Shinji Kimijima,et al.  Performance analysis of the SOFC–MGT hybrid system with gasified biomass fuel , 2007 .

[25]  W. Cǒté,et al.  Principles of Wood Science and Technology: I Solid Wood , 1977 .

[26]  David Kennedy,et al.  Computer simulation of a biomass gasification-solid oxide fuel cell power system using Aspen Plus , 2010 .

[27]  Paola Costamagna,et al.  Modeling of Solid Oxide Heat Exchanger Integrated Stacks and Simulation at High Fuel Utilization , 1998 .

[28]  S. Chan,et al.  A complete polarization model of a solid oxide fuel cell and its sensitivity to the change of cell component thickness , 2001 .

[29]  Jesper Ahrenfeldt,et al.  The design, construction and operation of a 75kW two-stage gasifier , 2006 .