Operating experience with chemical looping combustion in a 120kW dual circulating fluidized bed (DCFB) unit

In this study, first operating experience with a 120kW chemical looping pilot rig is presented. The dual circulating fluidized bed reactor system and its auxiliary units are discussed. Two different oxygen carries, i.e. ilmenite, which is a natural iron titanium ore and a designed Ni-based particle, are tested in the CLC unit. The pilot rig is fueled with H-2, CO and CH4 respectively at a fuel power of 65-145kW. High solids circulation, very low solids residence time and low solids inventory are observed during operation. Due to the scalability of the design concept, these characteristics should be quite similar to those of commercial CLC power plants. Ilmenite shows a high potential for the combustion of H-2 rich gases (e.g. from coal gasification with steam). The H-2 conversion is quite high but there is still a high potential for further improvement. The Ni-based oxygen carrier achieves the thermodynamic maximum H-2 and CO conversion and also very high CH4 conversion. A variation of the air/fuel ratio and the reaction temperature indicates that the Ni/NiO ratio of the particle has a high influence on the performance of the chemical looping combustor. (C) 2009 Vienna University of Technology. Published by Elsevier Ltd. All rights reserved.