Design and operation assessment of an oxyfuel fluidized bed combustor

Abstract Oxyfuel combustion is a promising alternative for CO 2 capture. While this has been proven in pulverized fuel (PF) burners, research in fluidized bed (FB) reactors is still scarce. Our work aims to increase the knowledge about this technology. To this purpose, a 95 kW th FB oxyfuel combustion test rig has been erected. Its main characteristics are described in this paper, giving detailed information on the subsystems: the FB reactor, the fuel and oxidant supplies, and ancillaries. Plant flexibility is emphasized. It allows to operate under different CO 2 /O 2 ratios, and to recycle CO 2 from the flue gases. Both the processes design and monitoring are supported by simulations that have been validated against experimental data, regarding fluid dynamics, combustion, and heat transfer. Finally, the performance of the facility has been tested both with coal alone and blended with biomass. CO 2 concentrations over 90% (dry basis) in the flue gases have been obtained. Comparison of air and oxygen combustion tests and operational recommendations are discussed, confirming the feasibility of the FB oxyfuel technology for CO 2 capture purposes.

[1]  Simulation of a full-scale pressurized fluidized bed combustor by using semi-empirical pilot plant correlations , 1998 .

[2]  Paolo Bolzern,et al.  A model of a bubbling fluidized bed combustor oriented to char mass estimation , 2000, IEEE Transactions on Control Systems Technology.

[3]  Andrew Drescher,et al.  Arching in hoppers: I. Arching theories and bulk material flow properties , 1995 .

[4]  Edward J. Anthony,et al.  Emissions of SO2 and NOx during Oxy−Fuel CFB Combustion Tests in a Mini-Circulating Fluidized Bed Combustion Reactor , 2010 .

[5]  Fabrizio Scala,et al.  Flue gas desulfurization under simulated oxyfiring fluidized bed combustion conditions: The influence of limestone attrition and fragmentation , 2010 .

[6]  Behdad Moghtaderi,et al.  An overview on oxyfuel coal combustion—State of the art research and technology development , 2009 .

[7]  Bo G Leckner,et al.  Fluidized bed combustion , 2013 .

[8]  P. N. Rowe,et al.  Prediction of bubble size in a gas fluidised bed , 1976 .

[9]  C. Y. Wen,et al.  Estimation of bubble diameter in gaseous fluidized beds , 1975 .

[10]  C. Wen.  Mechanics of Fluidization , 1966 .

[11]  Edward J. Anthony,et al.  Experimental Study of Oxy-Fuel Combustion and Sulfur Capture in a Mini-CFBC , 2007 .

[12]  Wojciech Nowak,et al.  Fuel conversion from oxy-fuel combustion in a circulating fluidized bed , 2006 .

[13]  Luis M. Romeo,et al.  Enhanced coal gasification heated by unmixed combustion integrated with an hybrid system of SOFC/GT , 2008 .

[14]  J. R. Howard.  Fluidized Bed Technology: Principles and Applications, , 1989 .

[15]  Borja Arias,et al.  Effect of biomass blending on coal ignition and burnout during oxy-fuel combustion , 2008 .

[16]  P. A. Jensen,et al.  Oxy-fuel combustion of solid fuels , 2010 .

[17]  A. Lyngfelt,et al.  A fluidized-bed combustion process with inherent CO2 separation; Application of chemical-looping combustion , 2001 .

[18]  RajenderKumar Gupta,et al.  Oxy-fuel combustion technology for coal-fired power generation , 2005 .

[19]  E. J. Anthony,et al.  Fluidized bed combustion systems integrating CO2 capture with CaO. , 2005, Environmental science & technology.

[20]  Hermann Hofbauer,et al.  Operating experience with chemical looping combustion in a 120 kW dual circulating fluidized bed (DCFB) unit , 2009 .

[21]  P. Basu.  Combustion and gasification in fluidized beds , 2006 .

[22]  Robin W. Hughes,et al.  Design, Process Simulation, and Construction of an Atmospheric Dual Fluidized Bed Combustion System for In Situ CO2 Capture Using High-temperature Sorbents , 2005 .

[23]  He Yurong,et al.  Size segregation of binary mixture of solids in bubbling fluidized beds , 2003 .