Pressurized chemical-looping combustion of coal using an iron ore as oxygen carrier in a pilot-scale unit

Abstract Chemical looping combustion (CLC) of coal is established as a new concept for inherent CO2 separation with the advantages of low cost and high conversion efficiency. A pilot-scale unit consisting of two fluidized bed reactors was constructed and operated to study the performance of pressurized chemical-looping combustion (PCLC). Experiments were conducted using Shenhua bituminous coal as fuel and MAC iron ore as oxygen carrier at three different operation pressures (0.1, 0.3 and 0.5 MPa) and the unit has been operated for totally 19 h with steady coal-feeding, about 13.5 h of which were realized under stable operation. The results showed that PCLC of coal demonstrated many remarkable advantages over the conventional CLC of coal, in terms of the improvement of carbon conversion in the fuel reactor, CO2 concentration of exhaust gas and combustion efficiency. At the operating pressure of 0.5 MPa, the CO2 concentration, carbon conversion and combustion efficiency reached very high values of 97.2, 84.7 and 95.5% respectively. The potential of low-cost iron ore as oxygen carrier for commercial coal-fueled CLC unit was also examined. The loss of oxygen carrier due to fine particles leaving the reactors increased with the increase of operation pressure and no agglomeration of oxygen carrier particles occurred during these tests. The oxygen carrier used in PCLC tests were also characterized by SEM-EDX and BET analysis to further emphasis on the effects of operation pressures and runtime.

[1]  Jun Xiao,et al.  Multicycle Study on Chemical-Looping Combustion of Simulated Coal Gas with a CaSO4 Oxygen Carrier in a Fluidized Bed Reactor , 2008 .

[2]  Wei-Ping Pan,et al.  Investigation of chemical looping combustion by solid fuels. 1. Process analysis , 2006 .

[3]  S. Bhattacharya,et al.  Use of Fe2O3-Containing Industrial Wastes As the Oxygen Carrier for Chemical-Looping Combustion of Coal: Effects of Pressure and Cycles , 2011 .

[4]  Anders Lyngfelt,et al.  Chemical-looping combustion in a 300 W continuously operating reactor system using a manganese-based oxygen carrier , 2006 .

[5]  Xiaoping Chen,et al.  Air blown partial gasification of coal in a pilot plant pressurized spout-fluid bed reactor , 2007 .

[6]  Duane D. Miller,et al.  Evaluation of reaction mechanism of coal-metal oxide interactions in chemical-looping combustion , 2010 .

[7]  Juan Adánez,et al.  Development of Cu-based oxygen carriers for chemical-looping combustion , 2004 .

[8]  Anders Lyngfelt,et al.  Batch testing of solid fuels with ilmenite in a 10 kWth chemical-looping combustor , 2010 .

[9]  M. Yazdanpanah,et al.  Construction and operation of a 10 kW CLC unit with circulation configuration enabling independent solid flow control , 2011 .

[10]  Juan Adánez,et al.  Ilmenite as oxygen carrier in a chemical looping combustion system with coal , 2011 .

[11]  A. Abad,et al.  Mapping of the range of operational conditions for Cu-, Fe-, and Ni-based oxygen carriers in chemical-looping combustion , 2007 .

[12]  Anders Lyngfelt,et al.  Solid fuels in chemical-looping combustion , 2008 .

[13]  A. Hoteit,et al.  Experimental investigation of CLC coal combustion with nickel based particles in a fluidized bed , 2012 .

[14]  Juan Adánez,et al.  Syngas combustion in a chemical-looping combustion system using an impregnated Ni-based oxygen carrier , 2009 .

[15]  Anders Lyngfelt,et al.  Natural minerals as oxygen carriers for chemical looping combustion in a dual circulating fluidized bed system , 2009 .

[16]  Craig Hawthorne,et al.  Use of ilmenite as an oxygen carrier in chemical looping combustion-batch and continuous dual fluidized bed investigation , 2011 .

[17]  Rui Xiao,et al.  Characterization and kinetics of reduction of CaSO4 with carbon monoxide for chemical-looping combustion , 2011 .

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

[19]  E. A. Goldstein,et al.  Chemical kinetics of copper oxide reduction with carbon monoxide , 2011 .

[20]  Jun Xiao,et al.  Chemical-Looping Combustion of Biomass in a 10 kWth Reactor with Iron Oxide As an Oxygen Carrier , 2009 .

[21]  Anders Lyngfelt,et al.  Solid fuels in chemical-looping combustion using a NiO-based oxygen carrier , 2009 .

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

[23]  Wei-Ping Pan,et al.  Investigation of Chemical Looping Combustion by Solid Fuels. 2. Redox Reaction Kinetics and Product Characterization with Coal, Biomass, and Solid Waste as Solid Fuels and CuO as an Oxygen Carrier , 2006 .

[24]  Jun Xiao,et al.  Chemical-looping combustion of methane with CaSO4 oxygen carrier in a fixed bed reactor , 2008 .

[25]  Chang-Keun Yi,et al.  Demonstration of inherent CO2 separation and no NOx emission in a 50kW chemical-looping combustor: Continuous reduction and oxidation experiment , 2005 .

[26]  Wenguang Zheng,et al.  Pressurized Chemical-Looping Combustion of Chinese Bituminous Coal: Cyclic Performance and Characterization of Iron Ore-Based Oxygen Carrier , 2010 .

[27]  Kunlei Liu,et al.  Oxygen carriers for chemical looping combustion of solid fuels , 2009 .

[28]  T. Mattisson,et al.  Redox investigation of some oxides of transition-state metals, Ni, Cu, Fe, and Mn Supported on SiO2 , 2005 .

[29]  A. Lyngfelt,et al.  Comparison of iron-, nickel-, copper- and manganese-based oxygen carriers for chemical-looping combustion , 2004 .

[30]  Chiranjib Saha,et al.  Comparison of CuO and NiO as oxygen carrier in chemical looping combustion of a Victorian brown coal , 2011 .

[31]  Kunlei Liu,et al.  Effect of Ash on Oxygen Carriers for the Application of Chemical Looping Combustion to a High Carbon Char , 2011 .

[32]  Rui Xiao,et al.  Reactivity of a CaSO4-oxygen carrier in chemical-looping combustion of methane in a fixed bed reactor , 2009 .

[33]  S. Bhattacharya,et al.  Chemical looping combustion of Victorian brown coal using NiO oxygen carrier , 2011 .

[34]  Anders Lyngfelt,et al.  160 hours of chemical-looping combustion in a 10 kW reactor system with a NiO-based oxygen carrier , 2008 .

[35]  Rui Xiao,et al.  Pressurized chemical-looping combustion of coal with an iron ore-based oxygen carrier , 2010 .

[36]  Stuart A. Scott,et al.  In situ gasification and CO2 separation using chemical looping with a Cu-based oxygen carrier: Performance with bituminous coals , 2010 .

[37]  Jun Xiao,et al.  Effect of Temperature on Reduction of CaSO4 Oxygen Carrier in Chemical-Looping Combustion of Simulated Coal Gas in a Fluidized Bed Reactor , 2008 .

[38]  Anders Lyngfelt,et al.  The use of petroleum coke as fuel in a 10 kWth chemical-looping combustor , 2008 .

[39]  Stuart A. Scott,et al.  In situ gasification of coal using steam with chemical looping: a technique for isolating CO2 from burning a solid fuel , 2006 .

[40]  Anders Lyngfelt,et al.  Design and Operation of a 10 kWth Chemical-Looping Combustor for Solid Fuels - Testing with South African Coal , 2008 .

[41]  Stuart A. Scott,et al.  In situ gasification of a solid fuel and CO2 separation using chemical looping , 2006 .

[42]  Anders Lyngfelt,et al.  Solid fuels in chemical-looping combustion using oxide scale and unprocessed iron ore as oxygen carriers , 2009 .